Laravel 4 with Sentry 2 add user to a group on Registration
Somehow, where you are using Sentry, you're not using its Facade, but the class itself. When you call a class through a Facade you're not really using statics, it's just looks like you are.
Do you have this:
use Cartalyst\Sentry\Sentry;
In your code?
Ok, but if this line is working for you:
$user = $this->sentry->register(array( 'username' => e($data['username']), 'email' => e($data['email']), 'password' => e($data['password']) ));
So you already have it instantiated and you can surely do:
$adminGroup = $this->sentry->findGroupById(5);
How to add CORS request in header in Angular 5
If you are like me and you are using a local SMS Gateway server and you make a GET request to an IP like 192.168.0.xx you will get for sure CORS error.
Unfortunately I could not find an Angular solution, but with the help of a previous replay I got my solution and I am posting an updated version for Angular 7 8 9
import {from} from 'rxjs';
getData(): Observable<any> {
return from(
fetch(
'http://xxxxx', // the url you are trying to access
{
headers: {
'Content-Type': 'application/json',
},
method: 'GET', // GET, POST, PUT, DELETE
mode: 'no-cors' // the most important option
}
));
}
Just .subscribe like the usual.
Hibernate Error executing DDL via JDBC Statement
I got this same error when i was trying to make a table with name "admin".
Then I used @Table annotation and gave table a different name like
@Table(name = "admins"). I think some words are reserved (like :- keywords in java) and you can not use them.
@Entity
@Table(name = "admins")
public class Admin extends TrackedEntity {
}
VueJs get url query
Current route properties are present in this.$route
, this.$router
is the instance of router object which gives the configuration of the router. You can get the current route query using this.$route.query
Possible to extend types in Typescript?
The keyword extends
can be used for interfaces and classes only.
If you just want to declare a type that has additional properties, you can use intersection type:
type UserEvent = Event & {UserId: string}
UPDATE for TypeScript 2.2, it's now possible to have an interface that extends object-like type, if the type satisfies some restrictions:
type Event = {
name: string;
dateCreated: string;
type: string;
}
interface UserEvent extends Event {
UserId: string;
}
It does not work the other way round - UserEvent
must be declared as interface, not a type
if you want to use extends
syntax.
And it's still impossible to use extend
with arbitrary types - for example, it does not work if Event
is a type parameter without any constraints.
Type of expression is ambiguous without more context Swift
The compiler can't figure out what type to make the Dictionary, because it's not homogenous. You have values of different types. The only way to get around this is to make it a [String: Any]
, which will make everything clunky as all hell.
return [
"title": title,
"is_draft": isDraft,
"difficulty": difficulty,
"duration": duration,
"cost": cost,
"user_id": userId,
"description": description,
"to_sell": toSell,
"images": [imageParameters, imageToDeleteParameters].flatMap { $0 }
] as [String: Any]
This is a job for a struct. It'll vastly simplify working with this data structure.
ASP.NET Core Identity - get current user
In .NET Core 2.0 the user already exists as part of the underlying inherited controller. Just use the User as you would normally or pass across to any repository code.
[Authorize(AuthenticationSchemes = JwtBearerDefaults.AuthenticationScheme, Policy = "TENANT")]
[HttpGet("issue-type-selection"), Produces("application/json")]
public async Task<IActionResult> IssueTypeSelection()
{
try
{
return new ObjectResult(await _item.IssueTypeSelection(User));
}
catch (ExceptionNotFound)
{
Response.StatusCode = (int)HttpStatusCode.BadRequest;
return Json(new
{
error = "invalid_grant",
error_description = "Item Not Found"
});
}
}
This is where it inherits it from
#region Assembly Microsoft.AspNetCore.Mvc.Core, Version=2.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60
// C:\Users\BhailDa\.nuget\packages\microsoft.aspnetcore.mvc.core\2.0.0\lib\netstandard2.0\Microsoft.AspNetCore.Mvc.Core.dll
#endregion
using System;
using System.IO;
using System.Linq.Expressions;
using System.Runtime.CompilerServices;
using System.Security.Claims;
using System.Text;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
using Microsoft.AspNetCore.Routing;
using Microsoft.Net.Http.Headers;
namespace Microsoft.AspNetCore.Mvc
{
//
// Summary:
// A base class for an MVC controller without view support.
[Controller]
public abstract class ControllerBase
{
protected ControllerBase();
//
// Summary:
// Gets the System.Security.Claims.ClaimsPrincipal for user associated with the
// executing action.
public ClaimsPrincipal User { get; }
Firebase Permission Denied
OK, but you don`t want to open the whole realtime database!
You need something like this.
{
/* Visit https://firebase.google.com/docs/database/security to learn more about security rules. */
"rules": {
".read": "auth.uid !=null",
".write": "auth.uid !=null"
}
}
or
{
"rules": {
"users": {
"$uid": {
".write": "$uid === auth.uid"
}
}
}
}
Re-render React component when prop changes
A friendly method to use is the following, once prop updates it will automatically rerender component:
render {
let textWhenComponentUpdate = this.props.text
return (
<View>
<Text>{textWhenComponentUpdate}</Text>
</View>
)
}
How to get current user in asp.net core
Most of the answers show how to best handle HttpContext
from the documentation, which is also what I went with.
I did want to mention that you'll want to check you project settings when debugging, the default is Enable Anonymous Authentication = true
.
onchange equivalent in angular2
We can use Angular event bindings to respond to any DOM event.
The syntax is simple. We surround the DOM event name in parentheses and assign a quoted template statement to it. -- reference
Since change
is on the list of standard DOM events, we can use it:
(change)="saverange()"
In your particular case, since you're using NgModel, you could break up the two-way binding like this instead:
[ngModel]="range" (ngModelChange)="saverange($event)"
Then
saverange(newValue) {
this.range = newValue;
this.Platform.ready().then(() => {
this.rootRef.child("users").child(this.UserID).child('range').set(this.range)
})
}
However, with this approach saverange()
is called with every keystroke, so you're probably better off using (change)
.
How to join multiple collections with $lookup in mongodb
You can actually chain multiple $lookup stages. Based on the names of the collections shared by profesor79, you can do this :
db.sivaUserInfo.aggregate([
{
$lookup: {
from: "sivaUserRole",
localField: "userId",
foreignField: "userId",
as: "userRole"
}
},
{
$unwind: "$userRole"
},
{
$lookup: {
from: "sivaUserInfo",
localField: "userId",
foreignField: "userId",
as: "userInfo"
}
},
{
$unwind: "$userInfo"
}
])
This will return the following structure :
{
"_id" : ObjectId("56d82612b63f1c31cf906003"),
"userId" : "AD",
"phone" : "0000000000",
"userRole" : {
"_id" : ObjectId("56d82612b63f1c31cf906003"),
"userId" : "AD",
"role" : "admin"
},
"userInfo" : {
"_id" : ObjectId("56d82612b63f1c31cf906003"),
"userId" : "AD",
"phone" : "0000000000"
}
}
Maybe this could be considered an anti-pattern because MongoDB wasn't meant to be relational but it is useful.
How to handle errors with boto3?
If you are calling the sign_up API (AWS Cognito) using Python3, you can use the following code.
def registerUser(userObj):
''' Registers the user to AWS Cognito.
'''
# Mobile number is not a mandatory field.
if(len(userObj['user_mob_no']) == 0):
mobilenumber = ''
else:
mobilenumber = userObj['user_country_code']+userObj['user_mob_no']
secretKey = bytes(settings.SOCIAL_AUTH_COGNITO_SECRET, 'latin-1')
clientId = settings.SOCIAL_AUTH_COGNITO_KEY
digest = hmac.new(secretKey,
msg=(userObj['user_name'] + clientId).encode('utf-8'),
digestmod=hashlib.sha256
).digest()
signature = base64.b64encode(digest).decode()
client = boto3.client('cognito-idp', region_name='eu-west-1' )
try:
response = client.sign_up(
ClientId=clientId,
Username=userObj['user_name'],
Password=userObj['password1'],
SecretHash=signature,
UserAttributes=[
{
'Name': 'given_name',
'Value': userObj['given_name']
},
{
'Name': 'family_name',
'Value': userObj['family_name']
},
{
'Name': 'email',
'Value': userObj['user_email']
},
{
'Name': 'phone_number',
'Value': mobilenumber
}
],
ValidationData=[
{
'Name': 'email',
'Value': userObj['user_email']
},
]
,
AnalyticsMetadata={
'AnalyticsEndpointId': 'string'
},
UserContextData={
'EncodedData': 'string'
}
)
except ClientError as error:
return {"errorcode": error.response['Error']['Code'],
"errormessage" : error.response['Error']['Message'] }
except Exception as e:
return {"errorcode": "Something went wrong. Try later or contact the admin" }
return {"success": "User registered successfully. "}
error.response['Error']['Code'] will be InvalidPasswordException, UsernameExistsException etc. So in the main function or where you are calling the function, you can write the logic to provide a meaningful message to the user.
An example for the response (error.response):
{
"Error": {
"Message": "Password did not conform with policy: Password must have symbol characters",
"Code": "InvalidPasswordException"
},
"ResponseMetadata": {
"RequestId": "c8a591d5-8c51-4af9-8fad-b38b270c3ca2",
"HTTPStatusCode": 400,
"HTTPHeaders": {
"date": "Wed, 17 Jul 2019 09:38:32 GMT",
"content-type": "application/x-amz-json-1.1",
"content-length": "124",
"connection": "keep-alive",
"x-amzn-requestid": "c8a591d5-8c51-4af9-8fad-b38b270c3ca2",
"x-amzn-errortype": "InvalidPasswordException:",
"x-amzn-errormessage": "Password did not conform with policy: Password must have symbol characters"
},
"RetryAttempts": 0
}
}
For further reference :
https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/cognito-idp.html#CognitoIdentityProvider.Client.sign_up
How to add a constant column in a Spark DataFrame?
In spark 2.2 there are two ways to add constant value in a column in DataFrame:
1) Using lit
2) Using typedLit
.
The difference between the two is that typedLit
can also handle parameterized scala types e.g. List, Seq, and Map
Sample DataFrame:
val df = spark.createDataFrame(Seq((0,"a"),(1,"b"),(2,"c"))).toDF("id", "col1")
+---+----+
| id|col1|
+---+----+
| 0| a|
| 1| b|
+---+----+
1) Using lit
: Adding constant string value in new column named newcol:
import org.apache.spark.sql.functions.lit
val newdf = df.withColumn("newcol",lit("myval"))
Result:
+---+----+------+
| id|col1|newcol|
+---+----+------+
| 0| a| myval|
| 1| b| myval|
+---+----+------+
2) Using typedLit
:
import org.apache.spark.sql.functions.typedLit
df.withColumn("newcol", typedLit(("sample", 10, .044)))
Result:
+---+----+-----------------+
| id|col1| newcol|
+---+----+-----------------+
| 0| a|[sample,10,0.044]|
| 1| b|[sample,10,0.044]|
| 2| c|[sample,10,0.044]|
+---+----+-----------------+
javascript Unable to get property 'value' of undefined or null reference
You can't access element like you did (document.frm_new_user_request
). You have to use the function getElementById
:
document.getElementById("frm_new_user_request")
So getting a value from an input could look like this:
var value = document.getElementById("frm_new_user_request").value
Also you can use some JavaScript framework, e.g. jQuery, which simplifies operations with DOM (Document Object Model) and also hides differences between various browsers from you.
Getting a value from an input using jQuery would look like this:
- input with ID "element":
var value = $("#element).value
- input with class "element":
var value = $(".element).value
Laravel csrf token mismatch for ajax POST Request
The best way to solve this problem "X-CSRF-TOKEN" is to add the following code to your main layout, and continue making your ajax calls normally:
In header
<meta name="csrf-token" content="{{ csrf_token() }}" />
In script
<script type="text/javascript">
$.ajaxSetup({
headers: {
'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
}
});
</script>
Fatal error: Call to a member function query() on null
put this line in parent construct : $this->load->database();
function __construct() {
parent::__construct();
$this->load->library('lib_name');
$model=array('model_name');
$this->load->model($model);
$this->load->database();
}
this way.. it should work..
How to get the current logged in user Id in ASP.NET Core
Until ASP.NET Core 1.0 RC1 :
It's User.GetUserId() from System.Security.Claims namespace.
Since ASP.NET Core 1.0 RC2 :
You now have to use UserManager.
You can create a method to get the current user :
private Task<ApplicationUser> GetCurrentUserAsync() => _userManager.GetUserAsync(HttpContext.User);
And get user information with the object :
var user = await GetCurrentUserAsync();
var userId = user?.Id;
string mail = user?.Email;
Note :
You can do it without using a method writing single lines like this string mail = (await _userManager.GetUserAsync(HttpContext.User))?.Email
, but it doesn't respect the single responsibility principle. It's better to isolate the way you get the user because if someday you decide to change your user management system, like use another solution than Identity, it will get painful since you have to review your entire code.
Spring Data JPA map the native query result to Non-Entity POJO
You can write your native or non-native query the way you want, and you can wrap JPQL query results with instances of custom result classes.
Create a DTO with the same names of columns returned in query and create an all argument constructor with same sequence and names as returned by the query.
Then use following way to query the database.
@Query("SELECT NEW example.CountryAndCapital(c.name, c.capital.name) FROM Country AS c")
Create DTO:
package example;
public class CountryAndCapital {
public String countryName;
public String capitalName;
public CountryAndCapital(String countryName, String capitalName) {
this.countryName = countryName;
this.capitalName = capitalName;
}
}
EntityType 'IdentityUserLogin' has no key defined. Define the key for this EntityType
By Changing The DbContext As Below;
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>();
modelBuilder.Conventions.Remove<ManyToManyCascadeDeleteConvention>();
}
Just adding in OnModelCreating
method call to base.OnModelCreating(modelBuilder); and it becomes fine. I am using EF6.
Special Thanks To #The Senator
android.content.Context.getPackageName()' on a null object reference
I had the same problem trying to show a Toast in a fragment.
After some debugging I found out that I was removing the fragment before calling:
Toast.makeText(getContext(), "text", Toast.LENGTH_SHORT).show();
Because the fragment had been removed, the context became null, causing the exception.
Simple solution: call the getContext()
before removing the fragment.
LoDash: Get an array of values from an array of object properties
_x000D_
_x000D_
const users = [{
id: 12,
name: 'Adam'
},{
id: 14,
name: 'Bob'
},{
id: 16,
name: 'Charlie'
},{
id: 18,
name: 'David'
}
]
const userIds = _.values(users);
console.log(userIds); //[12, 14, 16, 18]
_x000D_
_x000D_
_x000D_
How to extend available properties of User.Identity
For anyone that finds this question looking for how to access custom properties in ASP.NET Core 2.1 - it's much easier: You'll have a UserManager, e.g. in _LoginPartial.cshtml, and then you can simply do (assuming "ScreenName" is a property that you have added to your own AppUser which inherits from IdentityUser):
@using Microsoft.AspNetCore.Identity
@using <namespaceWhereYouHaveYourAppUser>
@inject SignInManager<AppUser> SignInManager
@inject UserManager<AppUser> UserManager
@if (SignInManager.IsSignedIn(User)) {
<form asp-area="Identity" asp-page="/Account/Logout" asp-route-returnUrl="@Url.Action("Index", "Home", new { area = "" })"
method="post" id="logoutForm"
class="form-inline my-2 my-lg-0">
<ul class="nav navbar-nav ml-auto">
<li class="nav-item">
<a class="nav-link" asp-area="Identity" asp-page="/Account/Manage/Index" title="Manage">
Hello @((await UserManager.GetUserAsync(User)).ScreenName)!
<!-- Original code, shows Email-Address: @UserManager.GetUserName(User)! -->
</a>
</li>
<li class="nav-item">
<button type="submit" class="btn btn-link nav-item navbar-link nav-link">Logout</button>
</li>
</ul>
</form>
} else {
<ul class="navbar-nav ml-auto">
<li class="nav-item"><a class="nav-link" asp-area="Identity" asp-page="/Account/Register">Register</a></li>
<li class="nav-item"><a class="nav-link" asp-area="Identity" asp-page="/Account/Login">Login</a></li>
</ul>
}
Multipart File Upload Using Spring Rest Template + Spring Web MVC
The Multipart File Upload worked after following code modification to Upload using RestTemplate
LinkedMultiValueMap<String, Object> map = new LinkedMultiValueMap<>();
map.add("file", new ClassPathResource(file));
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.MULTIPART_FORM_DATA);
HttpEntity<LinkedMultiValueMap<String, Object>> requestEntity = new HttpEntity<LinkedMultiValueMap<String, Object>>(
map, headers);
ResponseEntity<String> result = template.get().exchange(
contextPath.get() + path, HttpMethod.POST, requestEntity,
String.class);
And adding MultipartFilter to web.xml
<filter>
<filter-name>multipartFilter</filter-name>
<filter-class>org.springframework.web.multipart.support.MultipartFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>multipartFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
Laravel Eloquent Join vs Inner Join?
Probably not what you want to hear, but a "feeds" table would be a great middleman for this sort of transaction, giving you a denormalized way of pivoting to all these data with a polymorphic relationship.
You could build it like this:
<?php
Schema::create('feeds', function($table) {
$table->increments('id');
$table->timestamps();
$table->unsignedInteger('user_id');
$table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
$table->morphs('target');
});
Build the feed model like so:
<?php
class Feed extends Eloquent
{
protected $fillable = ['user_id', 'target_type', 'target_id'];
public function user()
{
return $this->belongsTo('User');
}
public function target()
{
return $this->morphTo();
}
}
Then keep it up to date with something like:
<?php
Vote::created(function(Vote $vote) {
$target_type = 'Vote';
$target_id = $vote->id;
$user_id = $vote->user_id;
Feed::create(compact('target_type', 'target_id', 'user_id'));
});
You could make the above much more generic/robust—this is just for demonstration purposes.
At this point, your feed items are really easy to retrieve all at once:
<?php
Feed::whereIn('user_id', $my_friend_ids)
->with('user', 'target')
->orderBy('created_at', 'desc')
->get();
No serializer found for class org.hibernate.proxy.pojo.javassist.Javassist?
I've the same problem right now.
check if you fix fetch in lazy with a @jsonIQgnore
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name="teachers")
@JsonIgnoreProperties("course")
Teacher teach;
Just delete the "(fetch=...)" or the annotation "@jsonIgnore" and it will work
@ManyToOne
@JoinColumn(name="teachers")
@JsonIgnoreProperties("course")
Teacher teach;
No function matches the given name and argument types
Your function has a couple of smallint
parameters.
But in the call, you are using numeric literals that are presumed to be type integer
.
A string literal or string constant ('123'
) is not typed immediately. It remains type "unknown" until assigned or cast explicitly.
However, a numeric literal or numeric constant is typed immediately. Per documentation:
A numeric constant that contains neither a decimal point nor an
exponent is initially presumed to be type integer
if its value
fits in type integer
(32 bits); otherwise it is presumed to be type
bigint
if its value fits in type bigint
(64 bits); otherwise it is
taken to be type numeric
. Constants that contain decimal points and/or
exponents are always initially presumed to be type numeric
.
More explanation and links in this related answer:
Solution
Add explicit casts for the smallint
parameters or quote them.
Demo
CREATE OR REPLACE FUNCTION f_typetest(smallint)
RETURNS bool AS 'SELECT TRUE' LANGUAGE sql;
Incorrect call:
SELECT * FROM f_typetest(1);
Correct calls:
SELECT * FROM f_typetest('1');
SELECT * FROM f_typetest(smallint '1');
SELECT * FROM f_typetest(1::int2);
SELECT * FROM f_typetest('1'::int2);
db<>fiddle here
Old sqlfiddle.
ASP.NET MVC - Attaching an entity of type 'MODELNAME' failed because another entity of the same type already has the same primary key value
i mange to fix the issue by updating state. when you trigger find or any other query operation on the same record sate has been updated with modified so we need to set status to Detached then you can fire your update change
ActivityEntity activity = new ActivityEntity();
activity.name="vv";
activity.ID = 22 ; //sample id
var savedActivity = context.Activities.Find(22);
if (savedActivity!=null)
{
context.Entry(savedActivity).State = EntityState.Detached;
context.SaveChanges();
activity.age= savedActivity.age;
activity.marks= savedActivity.marks;
context.Entry(activity).State = EntityState.Modified;
context.SaveChanges();
return activity.ID;
}
Ignore fields from Java object dynamically while sending as JSON from Spring MVC
I know I'm a bit late to the party, but I actually ran into this as well a few months back. All of the available solutions weren't very appealing to me (mixins? ugh!), so I ended up creating a new library to make this process cleaner. It's available here if anyone would like to try it out: https://github.com/monitorjbl/spring-json-view.
The basic usage is pretty simple, you use the JsonView
object in your controller methods like so:
import com.monitorjbl.json.JsonView;
import static com.monitorjbl.json.Match.match;
@RequestMapping(method = RequestMethod.GET, value = "/myObject")
@ResponseBody
public void getMyObjects() {
//get a list of the objects
List<MyObject> list = myObjectService.list();
//exclude expensive field
JsonView.with(list).onClass(MyObject.class, match().exclude("contains"));
}
You can also use it outside of Spring:
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import static com.monitorjbl.json.Match.match;
ObjectMapper mapper = new ObjectMapper();
SimpleModule module = new SimpleModule();
module.addSerializer(JsonView.class, new JsonViewSerializer());
mapper.registerModule(module);
mapper.writeValueAsString(JsonView.with(list)
.onClass(MyObject.class, match()
.exclude("contains"))
.onClass(MySmallObject.class, match()
.exclude("id"));
lambda expression join multiple tables with select and where clause
If I understand your questions correctly, all you need to do is add the .Where(m => m.r.u.UserId == 1):
var UserInRole = db.UserProfiles.
Join(db.UsersInRoles, u => u.UserId, uir => uir.UserId,
(u, uir) => new { u, uir }).
Join(db.Roles, r => r.uir.RoleId, ro => ro.RoleId, (r, ro) => new { r, ro })
.Where(m => m.r.u.UserId == 1)
.Select (m => new AddUserToRole
{
UserName = m.r.u.UserName,
RoleName = m.ro.RoleName
});
Hope that helps.
Oracle Trigger ORA-04098: trigger is invalid and failed re-validation
Cause: A trigger was attempted to be retrieved for execution and was found to be invalid. This also means that compilation/authorization failed for the trigger.
Action: Options are to resolve the compilation/authorization errors, disable the trigger, or drop the trigger.
Syntax
ALTER TRIGGER trigger Name DISABLE;
ALTER TRIGGER trigger_Name ENABLE;
How to show alert message in mvc 4 controller?
It is not possible to display alerts from the controller. Because MVC views and controllers are entirely separated from each other. You can only display information in the view only. So it is required to pass the information to be displayed from controller to view by using either ViewBag
, ViewData
or TempData
. If you are trying to display the content stored in TempData["Message"]
, It is possible to perform in the view page by adding few javascript lines.
<script>
alert(@TempData["Message"]);
</script>
Get current user id in ASP.NET Identity 2.0
I had the same issue. I am currently using Asp.net Core 2.2. I solved this problem with the following piece of code.
using Microsoft.AspNetCore.Identity;
var user = await _userManager.FindByEmailAsync(User.Identity.Name);
I hope this will be useful to someone.
How do I add button on each row in datatable?
I contribute with my settings for buttons: view, edit and delete.
The last column has data: null
At the end with the property defaultContent is added a string that HTML code. And since it is the last column, it is indicated with index -1 by means of the targets property when indicating the columns.
//...
columns: [
{ title: "", "data": null, defaultContent: '' }, //Si pone da error al cambiar de paginas la columna index con numero de fila
{ title: "Id", "data": "id", defaultContent: '', "visible":false },
{ title: "Nombre", "data": "nombre" },
{ title: "Apellido", "data": "apellido" },
{ title: "Documento", "data": "tipo_documento.siglas" },
{ title: "Numero", "data": "numero_documento" },
{ title: "Fec.Nac.", format: 'dd/mm/yyyy', "data": "fecha_nacimiento"}, //formato
{ title: "Teléfono", "data": "telefono1" },
{ title: "Email", "data": "email1" }
, { title: "", "data": null }
],
columnDefs: [
{
"searchable": false,
"orderable": false,
"targets": 0
},
{
width: '3%',
targets: 0 //la primer columna tendra una anchura del 20% de la tabla
},
{
targets: -1, //-1 es la ultima columna y 0 la primera
data: null,
defaultContent: '<div class="btn-group"> <button type="button" class="btn btn-info btn-xs dt-view" style="margin-right:16px;"><span class="glyphicon glyphicon-eye-open glyphicon-info-sign" aria-hidden="true"></span></button> <button type="button" class="btn btn-primary btn-xs dt-edit" style="margin-right:16px;"><span class="glyphicon glyphicon-pencil" aria-hidden="true"></span></button><button type="button" class="btn btn-danger btn-xs dt-delete"><span class="glyphicon glyphicon-remove glyphicon-trash" aria-hidden="true"></span></button></div>'
},
{ orderable: false, searchable: false, targets: -1 } //Ultima columna no ordenable para botones
],
//...
enter image description here
How to send data with angularjs $http.delete() request?
You can do an http DELETE via a URL like /users/1/roles/2. That would be the most RESTful way to do it.
Otherwise I guess you can just pass the user id as part of the query params? Something like
$http.delete('/roles/' + roleid, {params: {userId: userID}}).then...
Invalidating JSON Web Tokens
I'm a bit late here, but I think I have a decent solution.
I have a "last_password_change" column in my database that stores the date and time when the password was last changed. I also store the date/time of issue in the JWT. When validating a token, I check if the password has been changed after the token was issued and if it was the token is rejected even though it hasn't expired yet.
Mapping a JDBC ResultSet to an object
If you don't want to use any JPA provider such as OpenJPA or Hibernate, you can just give Apache DbUtils a try.
http://commons.apache.org/proper/commons-dbutils/examples.html
Then your code will look like this:
QueryRunner run = new QueryRunner(dataSource);
// Use the BeanListHandler implementation to convert all
// ResultSet rows into a List of Person JavaBeans.
ResultSetHandler<List<Person>> h = new BeanListHandler<Person>(Person.class);
// Execute the SQL statement and return the results in a List of
// Person objects generated by the BeanListHandler.
List<Person> persons = run.query("SELECT * FROM Person", h);
Get the current user, within an ApiController action, without passing the userID as a parameter
Hint lies in Webapi2 auto generated account controller
Have this property with getter defined as
public string UserIdentity
{
get
{
var user = UserManager.FindByName(User.Identity.Name);
return user;//user.Email
}
}
and in order to get UserManager - In WebApi2 -do as Romans (read as AccountController) do
public ApplicationUserManager UserManager
{
get { return HttpContext.Current.GetOwinContext().GetUserManager<ApplicationUserManager>(); }
}
This should be compatible in IIS and self host mode
MVC 5 Access Claims Identity User Data
Try this:
[Authorize]
public ActionResult SomeAction()
{
var identity = (ClaimsIdentity)User.Identity;
IEnumerable<Claim> claims = identity.Claims;
...
}
How to avoid page refresh after button click event in asp.net
I had the same problem with a button doing a page refresh before doing the actual button_click event (so the button had to be clicked twice).
This behavior happened after a server.transfer-command (server.transfer("testpage.aspx").
In this case, the solution was to replace the server.transfer-command with response-redirect (response.redirect("testpage.aspx").
For details on the differences between the two commands, see
Server.Transfer Vs. Response.Redirect
#1214 - The used table type doesn't support FULLTEXT indexes
Before MySQL 5.6 Full-Text Search is supported only with MyISAM Engine.
Therefore either change the engine for your table to MyISAM
CREATE TABLE gamemech_chat (
id bigint(20) unsigned NOT NULL auto_increment,
from_userid varchar(50) NOT NULL default '0',
to_userid varchar(50) NOT NULL default '0',
text text NOT NULL,
systemtext text NOT NULL,
timestamp datetime NOT NULL default '0000-00-00 00:00:00',
chatroom bigint(20) NOT NULL default '0',
PRIMARY KEY (id),
KEY from_userid (from_userid),
FULLTEXT KEY from_userid_2 (from_userid),
KEY chatroom (chatroom),
KEY timestamp (timestamp)
) ENGINE=MyISAM;
Here is SQLFiddle demo
or upgrade to 5.6 and use InnoDB Full-Text Search.
ASP.NET MVC 5 - Identity. How to get current ApplicationUser
The code of Ellbar works! You need only add using.
1 - using Microsoft.AspNet.Identity;
And... the code of Ellbar:
2 - string currentUserId = User.Identity.GetUserId();
ApplicationUser currentUser = db.Users.FirstOrDefault(x => x.Id == currentUserId);
With this code (in currentUser
), you work the general data of the connected user, if you want extra data... see this link
Caused By: java.lang.NoClassDefFoundError: org/apache/log4j/Logger
With the suggestions @jhadesdev and the explanations from others, I've found the issue here.
After adding the code to see what was visible to the various class loaders I found this:
All versions of log4j Logger:
zip:<snip>war/WEB-INF/lib/log4j-1.2.17.jar!/org/apache/log4j/Logger.class
All versions of log4j visible from the classloader of the OAuthAuthorizer class:
zip:<snip>war/WEB-INF/lib/log4j-1.2.17.jar!/org/apache/log4j/Logger.class
All versions of XMLConfigurator:
jar:<snip>com.bea.core.bea.opensaml2_1.0.0.0_6-1-0-0.jar!/org/opensaml/xml/XMLConfigurator.class
zip:<snip>war/WEB-INF/lib/ipp-java-aggcat-v1-devkit-1.0.2.jar!/org/opensaml/xml/XMLConfigurator.class
zip:<snip>war/WEB-INF/lib/xmltooling-1.3.1.jar!/org/opensaml/xml/XMLConfigurator.class
All versions of XMLConfigurator visible from the classloader of the OAuthAuthorizer class:
jar:<snip>com.bea.core.bea.opensaml2_1.0.0.0_6-1-0-0.jar!/org/opensaml/xml/XMLConfigurator.class
zip:<snip>war/WEB-INF/lib/ipp-java-aggcat-v1-devkit-1.0.2.jar!/org/opensaml/xml/XMLConfigurator.class
zip:<snip>war/WEB-INF/lib/xmltooling-1.3.1.jar!/org/opensaml/xml/XMLConfigurator.class
I noticed that another version of XMLConfigurator was possibly getting picked up.
I decompiled that class and found this at line 60 (where the error was in the original stack trace) private static final Logger log = Logger.getLogger(XMLConfigurator.class);
and that class was importing from org.apache.log4j.Logger
!
So it was this class that was being loaded and used. My fix was to rename the jar file that contained this file as I can't find where I explicitly or indirectly load it. Which may pose a problem when I actually deploy.
Thanks for all help and the much needed lesson on class loading.
Testing Spring's @RequestBody using Spring MockMVC
the following works for me,
mockMvc.perform(
MockMvcRequestBuilders.post("/api/test/url")
.contentType(MediaType.APPLICATION_JSON)
.content(asJsonString(createItemForm)))
.andExpect(status().isCreated());
public static String asJsonString(final Object obj) {
try {
return new ObjectMapper().writeValueAsString(obj);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
this is error ORA-12154: TNS:could not resolve the connect identifier specified?
run the below command in command prompt
tnsping Datasource
This should give a response like below
C:>tnsping *******
TNS Ping Utility for *** Windows: Version *** - Production on *****
Copyright (c) 1997, 2014, Oracle. All rights reserved.
Used parameter files:
c:\oracle*****
Used **** to resolve the alias
Attempting to contact (description=(address_list=(address=(protocol=tcp)(host=)(port=)))(connect_data=(server=)(service_name=)(failover_mode=(type=)(method=)(retries=)(delay=))))**
OK (**** msec)
Add the text 'Datasource=' in beginning and credentials at the end.
the final string should be
Data Source=(description=(address_list=(address=(protocol=tcp)(host=)(port=)))(connect_data=(server=)(service_name=)(failover_mode=(type=)(method=)(retries=)(delay=))));User Id=;Password=;**
Use this as the connection string to connect to oracle db.
Entity Framework change connection at runtime
Jim Tollan's answer works great, but I got the Error: Keyword not supported 'data source'.
To solve this problem I had to change this part of his code:
// add a reference to System.Configuration
var entityCnxStringBuilder = new EntityConnectionStringBuilder
(System.Configuration.ConfigurationManager
.ConnectionStrings[configNameEf].ConnectionString);
to this:
// add a reference to System.Configuration
var entityCnxStringBuilder = new EntityConnectionStringBuilder
{
ProviderConnectionString = new SqlConnectionStringBuilder(System.Configuration.ConfigurationManager
.ConnectionStrings[configNameEf].ConnectionString).ConnectionString
};
I'm really sorry. I know that I should't use answers to respond to other answers, but my answer is too long for a comment :(
How to get a URL parameter in Express?
This will work if your route looks like this: localhost:8888/p?tagid=1234
var tagId = req.query.tagid;
console.log(tagId); // outputs: 1234
console.log(req.query.tagid); // outputs: 1234
Otherwise use the following code if your route looks like this: localhost:8888/p/1234
var tagId = req.params.tagid;
console.log(tagId); // outputs: 1234
console.log(req.params.tagid); // outputs: 1234
How to upload file to server with HTTP POST multipart/form-data?
This simplistic version also works.
public void UploadMultipart(byte[] file, string filename, string contentType, string url)
{
var webClient = new WebClient();
string boundary = "------------------------" + DateTime.Now.Ticks.ToString("x");
webClient.Headers.Add("Content-Type", "multipart/form-data; boundary=" + boundary);
var fileData = webClient.Encoding.GetString(file);
var package = string.Format("--{0}\r\nContent-Disposition: form-data; name=\"file\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n{3}\r\n--{0}--\r\n", boundary, filename, contentType, fileData);
var nfile = webClient.Encoding.GetBytes(package);
byte[] resp = webClient.UploadData(url, "POST", nfile);
}
Add any extra required headers if needed.
Stored procedure or function expects parameter which is not supplied
In my case I received this exception even when all parameter values were correctly supplied but the type of command was not specified :
cmd.CommandType = System.Data.CommandType.StoredProcedure;
This is obviously not the case in the question above, but exception description is not very clear in this case, so I decided to specify that.
Add User to Role ASP.NET Identity
I had the same challenge. This is the solution I found to add users to roles.
internal class Security
{
ApplicationDbContext context = new ApplicationDbContext();
internal void AddUserToRole(string userName, string roleName)
{
var UserManager = new UserManager<ApplicationUser>(new UserStore<ApplicationUser>(context));
try
{
var user = UserManager.FindByName(userName);
UserManager.AddToRole(user.Id, roleName);
context.SaveChanges();
}
catch
{
throw;
}
}
}
How to set a header in an HTTP response?
In my Controller, I merely added an HttpServletResponse parameter and manually added the headers, no filter or intercept required and it works fine:
httpServletResponse.setHeader("Access-Control-Allow-Origin", "*");
httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET, OPTIONS");
httpServletResponse.setHeader("Access-Control-Allow-Headers","Origin, X-Requested-With, Content-Type, Accept, X-Auth-Token, X-Csrf-Token, WWW-Authenticate, Authorization");
httpServletResponse.setHeader("Access-Control-Allow-Credentials", "false");
httpServletResponse.setHeader("Access-Control-Max-Age", "3600");
SignalR - Sending a message to a specific user using (IUserIdProvider) *NEW 2.0.0*
This is how use SignarR in order to target a specific user (without using any provider):
private static ConcurrentDictionary<string, string> clients = new ConcurrentDictionary<string, string>();
public string Login(string username)
{
clients.TryAdd(Context.ConnectionId, username);
return username;
}
// The variable 'contextIdClient' is equal to Context.ConnectionId of the user,
// once logged in. You have to store that 'id' inside a dictionaty for example.
Clients.Client(contextIdClient).send("Hello!");
Unable to create a constant value of type Only primitive types or enumeration types are supported in this context
It's worth adding, since the OP's code sample doesn't provide enough context to prove otherwise, but I received this error as well on the following code:
public RetailSale GetByRefersToRetailSaleId(Int32 refersToRetailSaleId)
{
return GetQueryable()
.FirstOrDefault(x => x.RefersToRetailSaleId.Equals(refersToRetailSaleId));
}
Apparently, I cannot use Int32.Equals
in this context to compare an Int32 with a primitive int; I had to (safely) change to this:
public RetailSale GetByRefersToRetailSaleId(Int32 refersToRetailSaleId)
{
return GetQueryable()
.FirstOrDefault(x => x.RefersToRetailSaleId == refersToRetailSaleId);
}
Java escape JSON String?
org.json.simple.JSONObject.escape()
escapes quotes,, /, \r, \n, \b, \f, \t and other control characters.
import org.json.simple.JSONValue;
JSONValue.escape("test string");
Add pom.xml when using maven
<dependency>
<groupId>com.googlecode.json-simple</groupId>
<artifactId>json-simple</artifactId>
<scope>test</scope>
</dependency>
How to convert password into md5 in jquery?
Download and include this plugin
<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/3.1.2/rollups/md5.js"></script>
and use like
if(CryptoJS.MD5($("#txtOldPassword").val())) != oldPassword) {
}
//Following lines shows md5 value
//var hash = CryptoJS.MD5("Message");
//alert(hash);
Split a large dataframe into a list of data frames based on common value in column
You can just as easily access each element in the list using e.g. path[[1]]
. You can't put a set of matrices into an atomic vector and access each element. A matrix is an atomic vector with dimension attributes. I would use the list structure returned by split
, it's what it was designed for. Each list element can hold data of different types and sizes so it's very versatile and you can use *apply
functions to further operate on each element in the list. Example below.
# For reproducibile data
set.seed(1)
# Make some data
userid <- rep(1:2,times=4)
data1 <- replicate(8 , paste( sample(letters , 3 ) , collapse = "" ) )
data2 <- sample(10,8)
df <- data.frame( userid , data1 , data2 )
# Split on userid
out <- split( df , f = df$userid )
#$`1`
# userid data1 data2
#1 1 gjn 3
#3 1 yqp 1
#5 1 rjs 6
#7 1 jtw 5
#$`2`
# userid data1 data2
#2 2 xfv 4
#4 2 bfe 10
#6 2 mrx 2
#8 2 fqd 9
Access each element using the [[
operator like this:
out[[1]]
# userid data1 data2
#1 1 gjn 3
#3 1 yqp 1
#5 1 rjs 6
#7 1 jtw 5
Or use an *apply
function to do further operations on each list element. For instance, to take the mean of the data2
column you could use sapply like this:
sapply( out , function(x) mean( x$data2 ) )
# 1 2
#3.75 6.25
Implementing IDisposable correctly
Idisposable is implement whenever you want a deterministic (confirmed) garbage collection.
class Users : IDisposable
{
~Users()
{
Dispose(false);
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
// This method will remove current object from garbage collector's queue
// and stop calling finilize method twice
}
public void Dispose(bool disposer)
{
if (disposer)
{
// dispose the managed objects
}
// dispose the unmanaged objects
}
}
When creating and using the Users class use "using" block to avoid explicitly calling dispose method:
using (Users _user = new Users())
{
// do user related work
}
end of the using block created Users object will be disposed by implicit invoke of dispose method.
How to hide command output in Bash
A process normally has two outputs to screen: stdout (standard out), and stderr (standard error).
Normally informational messages go to sdout
, and errors and alerts go to stderr
.
You can turn off stdout
for a command by doing
MyCommand >/dev/null
and turn off stderr
by doing:
MyCommand 2>/dev/null
If you want both off, you can do:
MyCommand 2>&1 >/dev/null
The 2>&1
says send stderr to the same place as stdout.
How to use if, else condition in jsf to display image
For those like I who just followed the code by skuntsel and received a cryptic stack trace, allow me to save you some time.
It seems c:if
cannot by itself be followed by c:otherwise
.
The correct solution is as follows:
<c:choose>
<c:when test="#{some.test}">
<p>some.test is true</p>
</c:when>
<c:otherwise>
<p>some.test is not true</p>
</c:otherwise>
</c:choose>
You can add additional c:when
tests in as necessary.
Data was not saved: object references an unsaved transient instance - save the transient instance before flushing
You can't save things to Hibernate until you've also told Hibernate about all the other objects referenced by this newly saved object. So in this case, you're telling Hibernate about a User
, but haven't told it about the Country
.
You can solve problems like this in two ways.
Manually
Call session.save(country)
before you save the User
.
CascadeType
You can specify to Hibernate that this relationship should propagate some operations using CascadeType. In this case CascadeType.PERSIST would do the job, as would CascadeType.ALL.
Referencing existing countries
Based on your response to @zerocool though, you have a second problem, which is that when you have two User
objects with the same Country
, you are not making sure it's the same Country
. To do this, you have to get the appropriate Country
from the database, set it on the new user, and then save the User
. Then, both of your User
objects will refer to the same Country
, not just two Country
instances that happen to have the same name. Review the Criteria
API as one way of fetching existing instances.
How to generate and manually insert a uniqueidentifier in sql server?
Kindly check Column ApplicationId datatype in Table aspnet_Users , ApplicationId column datatype should be uniqueidentifier .
*Your parameter order is passed wrongly ,
Parameter @id should be passed as first argument, but in your script it is placed in second argument..*
So error is raised..
Please refere sample script:
DECLARE @id uniqueidentifier
SET @id = NEWID()
Create Table #temp1(AppId uniqueidentifier)
insert into #temp1 values(@id)
Select * from #temp1
Drop Table #temp1
How to generate and auto increment Id with Entity Framework
You have a bad table design. You can't autoincrement a string, that doesn't make any sense. You have basically two options:
1.) change type of ID to int
instead of string
2.) not recommended!!! - handle autoincrement by yourself. You first need to get the latest value from the database, parse it to the integer, increment it and attach it to the entity as a string again. VERY BAD idea
First option requires to change every table that has a reference to this table, BUT it's worth it.
How can I pass a username/password in the header to a SOAP WCF Service
Suppose you are calling a web service using HttpWebRequest and HttpWebResponse, because .Net client doest support the structure of the WSLD that your are trying to consume.
In that case you can add the security credentials on the headers like:
<soap:Envelpe>
<soap:Header>
<wsse:Security soap:mustUnderstand='true' xmlns:wsse='http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd' xmlns:wsu='http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd'><wsse:UsernameToken wsu:Id='UsernameToken-3DAJDJSKJDHFJASDKJFKJ234JL2K3H2K3J42'><wsse:Username>YOU_USERNAME/wsse:Username><wsse:Password Type='http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-username-token-profile-1.0#PasswordText'>YOU_PASSWORD</wsse:Password><wsse:Nonce EncodingType='http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0#Base64Binary'>3WSOKcKKm0jdi3943ts1AQ==</wsse:Nonce><wsu:Created>2015-01-12T16:46:58.386Z</wsu:Created></wsse:UsernameToken></wsse:Security>
</soapHeather>
<soap:Body>
</soap:Body>
</soap:Envelope>
You can use SOAPUI to get the wsse Security, using the http log.
Be careful because it is not a safe scenario.
SQL Server : converting varchar to INT
This question has got 91,000 views so perhaps many people are looking for a more generic solution to the issue in the title "error converting varchar to INT"
If you are on SQL Server 2012+ one way of handling this invalid data is to use TRY_CAST
SELECT TRY_CAST (userID AS INT)
FROM audit
On previous versions you could use
SELECT CASE
WHEN ISNUMERIC(RTRIM(userID) + '.0e0') = 1
AND LEN(userID) <= 11
THEN CAST(userID AS INT)
END
FROM audit
Both return NULL
if the value cannot be cast.
In the specific case that you have in your question with known bad values I would use the following however.
CAST(REPLACE(userID COLLATE Latin1_General_Bin, CHAR(0),'') AS INT)
Trying to replace the null character is often problematic except if using a binary collation.
How to pass parameters in GET requests with jQuery
The data parameter of ajax method allows you send data to server side.On server side you can request the data.See the code
var id=5;
$.ajax({
type: "get",
url: "url of server side script",
data:{id:id},
success: function(res){
console.log(res);
},
error:function(error)
{
console.log(error);
}
});
At server side receive it using $_GET variable.
$_GET['id'];
Pass Javascript variable to PHP via ajax
Alternatively, try removing "data" and making the URL "logtime.php?userID="+userId
I like Brian's answer better, this answer is just because you're trying to use URL parameter syntax in "data" and I wanted to demonstrate where you can use that syntax correctly.
Entity Framework 5 Updating a Record
I have added an extra update method onto my repository base class that's similar to the update method generated by Scaffolding. Instead of setting the entire object to "modified", it sets a set of individual properties. (T is a class generic parameter.)
public void Update(T obj, params Expression<Func<T, object>>[] propertiesToUpdate)
{
Context.Set<T>().Attach(obj);
foreach (var p in propertiesToUpdate)
{
Context.Entry(obj).Property(p).IsModified = true;
}
}
And then to call, for example:
public void UpdatePasswordAndEmail(long userId, string password, string email)
{
var user = new User {UserId = userId, Password = password, Email = email};
Update(user, u => u.Password, u => u.Email);
Save();
}
I like one trip to the database. Its probably better to do this with view models, though, in order to avoid repeating sets of properties. I haven't done that yet because I don't know how to avoid bringing the validation messages on my view model validators into my domain project.
Creating a SOAP call using PHP with an XML body
First off, you have to specify you wish to use Document Literal style:
$client = new SoapClient(NULL, array(
'location' => 'https://example.com/path/to/service',
'uri' => 'http://example.com/wsdl',
'trace' => 1,
'use' => SOAP_LITERAL)
);
Then, you need to transform your data into a SoapVar; I've written a simple transform function:
function soapify(array $data)
{
foreach ($data as &$value) {
if (is_array($value)) {
$value = soapify($value);
}
}
return new SoapVar($data, SOAP_ENC_OBJECT);
}
Then, you apply this transform function onto your data:
$data = soapify(array(
'Acquirer' => array(
'Id' => 'MyId',
'UserId' => 'MyUserId',
'Password' => 'MyPassword',
),
));
Finally, you call the service passing the Data parameter:
$method = 'Echo';
$result = $client->$method(new SoapParam($data, 'Data'));
How can I drop a table if there is a foreign key constraint in SQL Server?
You have to drop the constraint before drop your table.
You can use those queries to find all FKs in your table and find the FKs in the tables in which your table is used.
Declare @SchemaName VarChar(200) = 'Your Schema name'
Declare @TableName VarChar(200) = 'Your Table Name'
-- Find FK in This table.
SELECT
' IF EXISTS (SELECT * FROM sys.foreign_keys WHERE object_id =
OBJECT_ID(N''' +
'[' + OBJECT_SCHEMA_NAME(FK.parent_object_id) + '].[' + FK.name + ']'
+ ''') AND parent_object_id = OBJECT_ID(N''' +
'[' + OBJECT_SCHEMA_NAME(FK.parent_object_id) + '].[' +
OBJECT_NAME(FK.parent_object_id) + ']' + ''')) ' +
'ALTER TABLE ' + OBJECT_SCHEMA_NAME(FK.parent_object_id) +
'.[' + OBJECT_NAME(FK.parent_object_id) +
'] DROP CONSTRAINT ' + FK.name
, S.name , O.name, OBJECT_NAME(FK.parent_object_id)
FROM sys.foreign_keys AS FK
INNER JOIN Sys.objects As O
ON (O.object_id = FK.parent_object_id )
INNER JOIN SYS.schemas AS S
ON (O.schema_id = S.schema_id)
WHERE
O.name = @TableName
And S.name = @SchemaName
-- Find the FKs in the tables in which this table is used
SELECT
' IF EXISTS (SELECT * FROM sys.foreign_keys WHERE object_id =
OBJECT_ID(N''' +
'[' + OBJECT_SCHEMA_NAME(FK.parent_object_id) + '].[' + FK.name + ']'
+ ''') AND parent_object_id = OBJECT_ID(N''' +
'[' + OBJECT_SCHEMA_NAME(FK.parent_object_id) + '].[' +
OBJECT_NAME(FK.parent_object_id) + ']' + ''')) ' +
' ALTER TABLE ' + OBJECT_SCHEMA_NAME(FK.parent_object_id) +
'.[' + OBJECT_NAME(FK.parent_object_id) +
'] DROP CONSTRAINT ' + FK.name
, S.name , O.name, OBJECT_NAME(FK.parent_object_id)
FROM sys.foreign_keys AS FK
INNER JOIN Sys.objects As O
ON (O.object_id = FK.referenced_object_id )
INNER JOIN SYS.schemas AS S
ON (O.schema_id = S.schema_id)
WHERE
O.name = @TableName
And S.name = @SchemaName
How to show row number in Access query like ROW_NUMBER in SQL
One way to do this with MS Access is with a subquery but it does not have anything like the same functionality:
SELECT a.ID,
a.AText,
(SELECT Count(ID)
FROM table1 b WHERE b.ID <= a.ID
AND b.AText Like "*a*") AS RowNo
FROM Table1 AS a
WHERE a.AText Like "*a*"
ORDER BY a.ID;
TSQL CASE with if comparison in SELECT statement
Should be:
SELECT registrationDate,
(SELECT CASE
WHEN COUNT(*)< 2 THEN 'Ama'
WHEN COUNT(*)< 5 THEN 'SemiAma'
WHEN COUNT(*)< 7 THEN 'Good'
WHEN COUNT(*)< 9 THEN 'Better'
WHEN COUNT(*)< 12 THEN 'Best'
ELSE 'Outstanding'
END as a FROM Articles
WHERE Articles.userId = Users.userId) as ranking,
(SELECT COUNT(*)
FROM Articles
WHERE userId = Users.userId) as articleNumber,
hobbies, etc...
FROM USERS
Change UITableView height dynamically
Rob's solution is very nice, only thing that in his -(void)adjustHeightOfTableview
method the calling of
[self.view needsUpdateConstraints]
does nothing, it just returns a flag, instead calling
[self.view setNeedsUpdateConstraints]
will make the desired effect.
Cannot enqueue Handshake after invoking quit
You can use
debug: false,
Example:
//mysql connection
var dbcon1 = mysql.createConnection({
host: "localhost",
user: "root",
password: "",
database: "node5",
debug: false,
});
Can Flask have optional URL parameters?
You can write as you show in example, but than you get build-error.
For fix this:
- print app.url_map () in you root .py
- you see something like:
<Rule '/<userId>/<username>' (HEAD, POST, OPTIONS, GET) -> user.show_0>
and
<Rule '/<userId>' (HEAD, POST, OPTIONS, GET) -> .show_1>
- than in template you can
{{ url_for('.show_0', args) }}
and {{ url_for('.show_1', args) }}
Construct pandas DataFrame from items in nested dictionary
pd.concat
accepts a dictionary. With this in mind, it is possible to improve upon the currently accepted answer in terms of simplicity and performance by use a dictionary comprehension to build a dictionary mapping keys to sub-frames.
pd.concat({k: pd.DataFrame(v).T for k, v in user_dict.items()}, axis=0)
Or,
pd.concat({
k: pd.DataFrame.from_dict(v, 'index') for k, v in user_dict.items()
},
axis=0)
att_1 att_2
12 Category 1 1 whatever
Category 2 23 another
15 Category 1 10 foo
Category 2 30 bar
Decode UTF-8 with Javascript
Update @Albert's answer adding condition for emoji.
function Utf8ArrayToStr(array) {
var out, i, len, c;
var char2, char3, char4;
out = "";
len = array.length;
i = 0;
while(i < len) {
c = array[i++];
switch(c >> 4)
{
case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
// 0xxxxxxx
out += String.fromCharCode(c);
break;
case 12: case 13:
// 110x xxxx 10xx xxxx
char2 = array[i++];
out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));
break;
case 14:
// 1110 xxxx 10xx xxxx 10xx xxxx
char2 = array[i++];
char3 = array[i++];
out += String.fromCharCode(((c & 0x0F) << 12) |
((char2 & 0x3F) << 6) |
((char3 & 0x3F) << 0));
break;
case 15:
// 1111 0xxx 10xx xxxx 10xx xxxx 10xx xxxx
char2 = array[i++];
char3 = array[i++];
char4 = array[i++];
out += String.fromCodePoint(((c & 0x07) << 18) | ((char2 & 0x3F) << 12) | ((char3 & 0x3F) << 6) | (char4 & 0x3F));
break;
}
return out;
}
How to pass a textbox value from view to a controller in MVC 4?
Try the following in your view to check the output from each. The first one updates when the view is called a second time. My controller uses the key ShowCreateButton and has the optional parameter _createAction with a default value - you can change this to your key/parameter
@Html.TextBox("_createAction", null, new { Value = (string)ViewBag.ShowCreateButton })
@Html.TextBox("_createAction", ViewBag.ShowCreateButton )
@ViewBag.ShowCreateButton
Passing parameters to a JDBC PreparedStatement
There is a problem in your query..
statement =con.prepareStatement("SELECT * from employee WHERE userID = "+"''"+userID);
ResultSet rs = statement.executeQuery();
You are using Prepare Statement.. So you need to set your parameter using statement.setInt()
or statement.setString()
depending upon what is the type of your userId
Replace it with: -
statement =con.prepareStatement("SELECT * from employee WHERE userID = :userId");
statement.setString(userId, userID);
ResultSet rs = statement.executeQuery();
Or, you can use ?
in place of named value - :userId
..
statement =con.prepareStatement("SELECT * from employee WHERE userID = ?");
statement.setString(1, userID);
Using curl to upload POST data with files
The issue that lead me here turned out to be a basic user error - I wasn't including the @
sign in the path of the file and so curl was posting the path/name of the file rather than the contents. The Content-Length
value was therefore 8 rather than the 479 I expected to see given the legnth of my test file.
The Content-Length
header will be automatically calculated when curl reads and posts the file.
curl -i -H "Content-Type: application/xml" --data "@test.xml" -v -X POST https://<url>/<uri/
...
< Content-Length: 479
...
Posting this here to assist other newbies in future.
Loading and parsing a JSON file with multiple JSON objects
You have a JSON Lines format text file. You need to parse your file line by line:
import json
data = []
with open('file') as f:
for line in f:
data.append(json.loads(line))
Each line contains valid JSON, but as a whole, it is not a valid JSON value as there is no top-level list or object definition.
Note that because the file contains JSON per line, you are saved the headaches of trying to parse it all in one go or to figure out a streaming JSON parser. You can now opt to process each line separately before moving on to the next, saving memory in the process. You probably don't want to append each result to one list and then process everything if your file is really big.
If you have a file containing individual JSON objects with delimiters in-between, use How do I use the 'json' module to read in one JSON object at a time? to parse out individual objects using a buffered method.
Twitter Bootstrap and ASP.NET GridView
Add property of show header in gridview
<asp:GridView ID="dgvUsers" runat="server" **showHeader="True"** CssClass="table table-hover table-striped" GridLines="None"
AutoGenerateColumns="False">
and in columns add header template
<HeaderTemplate>
//header column names
</HeaderTemplate>
LDAP Authentication using Java
Following Code authenticates from LDAP using pure Java JNDI. The Principle is:-
- First Lookup the user using a admin or DN user.
- The user object needs to be passed to LDAP again with the user credential
- No Exception means - Authenticated Successfully. Else Authentication Failed.
Code Snippet
public static boolean authenticateJndi(String username, String password) throws Exception{
Properties props = new Properties();
props.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
props.put(Context.PROVIDER_URL, "ldap://LDAPSERVER:PORT");
props.put(Context.SECURITY_PRINCIPAL, "uid=adminuser,ou=special users,o=xx.com");//adminuser - User with special priviledge, dn user
props.put(Context.SECURITY_CREDENTIALS, "adminpassword");//dn user password
InitialDirContext context = new InitialDirContext(props);
SearchControls ctrls = new SearchControls();
ctrls.setReturningAttributes(new String[] { "givenName", "sn","memberOf" });
ctrls.setSearchScope(SearchControls.SUBTREE_SCOPE);
NamingEnumeration<javax.naming.directory.SearchResult> answers = context.search("o=xx.com", "(uid=" + username + ")", ctrls);
javax.naming.directory.SearchResult result = answers.nextElement();
String user = result.getNameInNamespace();
try {
props = new Properties();
props.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
props.put(Context.PROVIDER_URL, "ldap://LDAPSERVER:PORT");
props.put(Context.SECURITY_PRINCIPAL, user);
props.put(Context.SECURITY_CREDENTIALS, password);
context = new InitialDirContext(props);
} catch (Exception e) {
return false;
}
return true;
}
How to insert data into SQL Server
You have to set Connection property of Command object and use parametersized query instead of hardcoded SQL to avoid SQL Injection.
using(SqlConnection openCon=new SqlConnection("your_connection_String"))
{
string saveStaff = "INSERT into tbl_staff (staffName,userID,idDepartment) VALUES (@staffName,@userID,@idDepartment)";
using(SqlCommand querySaveStaff = new SqlCommand(saveStaff))
{
querySaveStaff.Connection=openCon;
querySaveStaff.Parameters.Add("@staffName",SqlDbType.VarChar,30).Value=name;
.....
openCon.Open();
querySaveStaff.ExecuteNonQuery();
}
}
Passing array in GET for a REST call
Instead of using http GET, use http POST. And JSON. Or XML
This is how your request stream to the server would look like.
POST /appointments HTTP/1.0
Content-Type: application/json
Content-Length: (calculated by your utility)
{users: [user:{id:id1}, user:{id:id2}]}
Or in XML,
POST /appointments HTTP/1.0
Content-Type: application/json
Content-Length: (calculated by your utility)
<users><user id='id1'/><user id='id2'/></users>
You could certainly continue using GET as you have proposed, as it is certainly simpler.
/appointments?users=1d1,1d2
Which means you would have to keep your data structures very simple.
However, if/when your data structure gets more complex, http GET and without JSON, your programming and ability to recognise the data gets very difficult.
Therefore,unless you could keep your data structure simple, I urge you adopt a data transfer framework. If your requests are browser based, the industry usual practice is JSON. If your requests are server-server, than XML is the most convenient framework.
JQuery
If your client is a browser and you are not using GWT, you should consider using jquery REST. Google on RESTful services with jQuery.
How do I update an entity using spring-data-jpa?
As what has already mentioned by others, the save()
itself contains both create and update operation.
I just want to add supplement about what behind the save()
method.
Firstly, let's see the extend/implement hierarchy of the CrudRepository<T,ID>
,
Ok, let's check the save()
implementation at SimpleJpaRepository<T, ID>
,
@Transactional
public <S extends T> S save(S entity) {
if (entityInformation.isNew(entity)) {
em.persist(entity);
return entity;
} else {
return em.merge(entity);
}
}
As you can see, it will check whether the ID is existed or not firstly, if the entity is already there, only update will happen by merge(entity)
method and if else, a new record is inserted by persist(entity)
method.
Comparing mongoose _id and strings
I faced exactly the same problem and i simply resolved the issue with the help of JSON.stringify()
as follow:-
if (JSON.stringify(results.userId) === JSON.stringify(AnotherMongoDocument._id)) {
console.log('This is never true');
}
First char to upper case
String toCamelCase(String string) {
StringBuffer sb = new StringBuffer(string);
sb.replace(0, 1, string.substring(0, 1).toUpperCase());
return sb.toString();
}
Hibernate: get entity by id
In getUserById
you shouldn't create a new object (user1) which isn't used. Just assign it to the already (but null) initialized user
. Otherwise Hibernate.initialize(user);
is actually Hibernate.initialize(null);
Here's the new getUserById
(I haven't tested this ;)):
public User getUserById(Long user_id) {
Session session = null;
Object user = null;
try {
session = HibernateUtil.getSessionFactory().openSession();
user = (User)session.load(User.class, user_id);
Hibernate.initialize(user);
} catch (Exception e) {
e.printStackTrace();
} finally {
if (session != null && session.isOpen()) {
session.close();
}
}
return user;
}
How to change the value of attribute in appSettings section with Web.config transformation
I do not like transformations to have any more info than needed. So instead of restating the keys, I simply state the condition and intention. It is much easier to see the intention when done like this, at least IMO. Also, I try and put all the xdt
attributes first to indicate to the reader, these are transformations and not new things being defined.
<appSettings>
<add xdt:Locator="Condition(@key='developmentModeUserId')" xdt:Transform="Remove" />
<add xdt:Locator="Condition(@key='developmentMode')" xdt:Transform="SetAttributes"
value="false"/>
</appSettings>
In the above it is much easier to see that the first one is removing the element. The 2nd one is setting attributes. It will set/replace any attributes you define here. In this case it will simply set value
to false
.
Is it fine to have foreign key as primary key?
Foreign keys are almost always "Allow Duplicates," which would make them unsuitable as Primary Keys.
Instead, find a field that uniquely identifies each record in the table, or add a new field (either an auto-incrementing integer or a GUID) to act as the primary key.
The only exception to this are tables with a one-to-one relationship, where the foreign key and primary key of the linked table are one and the same.
How to encrypt/decrypt data in php?
Foreword
Starting with your table definition:
- UserID
- Fname
- Lname
- Email
- Password
- IV
Here are the changes:
- The fields
Fname
, Lname
and Email
will be encrypted using a symmetric cipher, provided by OpenSSL,
- The
IV
field will store the initialisation vector used for encryption. The storage requirements depend on the cipher and mode used; more about this later.
- The
Password
field will be hashed using a one-way password hash,
Encryption
Cipher and mode
Choosing the best encryption cipher and mode is beyond the scope of this answer, but the final choice affects the size of both the encryption key and initialisation vector; for this post we will be using AES-256-CBC which has a fixed block size of 16 bytes and a key size of either 16, 24 or 32 bytes.
Encryption key
A good encryption key is a binary blob that's generated from a reliable random number generator. The following example would be recommended (>= 5.3):
$key_size = 32; // 256 bits
$encryption_key = openssl_random_pseudo_bytes($key_size, $strong);
// $strong will be true if the key is crypto safe
This can be done once or multiple times (if you wish to create a chain of encryption keys). Keep these as private as possible.
IV
The initialisation vector adds randomness to the encryption and required for CBC mode. These values should be ideally be used only once (technically once per encryption key), so an update to any part of a row should regenerate it.
A function is provided to help you generate the IV:
$iv_size = 16; // 128 bits
$iv = openssl_random_pseudo_bytes($iv_size, $strong);
Example
Let's encrypt the name field, using the earlier $encryption_key
and $iv
; to do this, we have to pad our data to the block size:
function pkcs7_pad($data, $size)
{
$length = $size - strlen($data) % $size;
return $data . str_repeat(chr($length), $length);
}
$name = 'Jack';
$enc_name = openssl_encrypt(
pkcs7_pad($name, 16), // padded data
'AES-256-CBC', // cipher and mode
$encryption_key, // secret key
0, // options (not used)
$iv // initialisation vector
);
Storage requirements
The encrypted output, like the IV, is binary; storing these values in a database can be accomplished by using designated column types such as BINARY
or VARBINARY
.
The output value, like the IV, is binary; to store those values in MySQL, consider using BINARY
or VARBINARY
columns. If this is not an option, you can also convert the binary data into a textual representation using base64_encode()
or bin2hex()
, doing so requires between 33% to 100% more storage space.
Decryption
Decryption of the stored values is similar:
function pkcs7_unpad($data)
{
return substr($data, 0, -ord($data[strlen($data) - 1]));
}
$row = $result->fetch(PDO::FETCH_ASSOC); // read from database result
// $enc_name = base64_decode($row['Name']);
// $enc_name = hex2bin($row['Name']);
$enc_name = $row['Name'];
// $iv = base64_decode($row['IV']);
// $iv = hex2bin($row['IV']);
$iv = $row['IV'];
$name = pkcs7_unpad(openssl_decrypt(
$enc_name,
'AES-256-CBC',
$encryption_key,
0,
$iv
));
Authenticated encryption
You can further improve the integrity of the generated cipher text by appending a signature that's generated from a secret key (different from the encryption key) and the cipher text. Before the cipher text is decrypted, the signature is first verified (preferably with a constant-time comparison method).
Example
// generate once, keep safe
$auth_key = openssl_random_pseudo_bytes(32, $strong);
// authentication
$auth = hash_hmac('sha256', $enc_name, $auth_key, true);
$auth_enc_name = $auth . $enc_name;
// verification
$auth = substr($auth_enc_name, 0, 32);
$enc_name = substr($auth_enc_name, 32);
$actual_auth = hash_hmac('sha256', $enc_name, $auth_key, true);
if (hash_equals($auth, $actual_auth)) {
// perform decryption
}
See also: hash_equals()
Hashing
Storing a reversible password in your database must be avoided as much as possible; you only wish to verify the password rather than knowing its contents. If a user loses their password, it's better to allow them to reset it rather than sending them their original one (make sure that password reset can only be done for a limited time).
Applying a hash function is a one-way operation; afterwards it can be safely used for verification without revealing the original data; for passwords, a brute force method is a feasible approach to uncover it due to its relatively short length and poor password choices of many people.
Hashing algorithms such as MD5 or SHA1 were made to verify file contents against a known hash value. They're greatly optimized to make this verification as fast as possible while still being accurate. Given their relatively limited output space it was easy to build a database with known passwords and their respective hash outputs, the rainbow tables.
Adding a salt to the password before hashing it would render a rainbow table useless, but recent hardware advancements made brute force lookups a viable approach. That's why you need a hashing algorithm that's deliberately slow and simply impossible to optimize. It should also be able to increase the load for faster hardware without affecting the ability to verify existing password hashes to make it future proof.
Currently there are two popular choices available:
- PBKDF2 (Password Based Key Derivation Function v2)
- bcrypt (aka Blowfish)
This answer will use an example with bcrypt.
Generation
A password hash can be generated like this:
$password = 'my password';
$random = openssl_random_pseudo_bytes(18);
$salt = sprintf('$2y$%02d$%s',
13, // 2^n cost factor
substr(strtr(base64_encode($random), '+', '.'), 0, 22)
);
$hash = crypt($password, $salt);
The salt is generated with openssl_random_pseudo_bytes()
to form a random blob of data which is then run through base64_encode()
and strtr()
to match the required alphabet of [A-Za-z0-9/.]
.
The crypt()
function performs the hashing based on the algorithm ($2y$
for Blowfish), the cost factor (a factor of 13 takes roughly 0.40s on a 3GHz machine) and the salt of 22 characters.
Validation
Once you have fetched the row containing the user information, you validate the password in this manner:
$given_password = $_POST['password']; // the submitted password
$db_hash = $row['Password']; // field with the password hash
$given_hash = crypt($given_password, $db_hash);
if (isEqual($given_hash, $db_hash)) {
// user password verified
}
// constant time string compare
function isEqual($str1, $str2)
{
$n1 = strlen($str1);
if (strlen($str2) != $n1) {
return false;
}
for ($i = 0, $diff = 0; $i != $n1; ++$i) {
$diff |= ord($str1[$i]) ^ ord($str2[$i]);
}
return !$diff;
}
To verify a password, you call crypt()
again but you pass the previously calculated hash as the salt value. The return value yields the same hash if the given password matches the hash. To verify the hash, it's often recommended to use a constant-time comparison function to avoid timing attacks.
Password hashing with PHP 5.5
PHP 5.5 introduced the password hashing functions that you can use to simplify the above method of hashing:
$hash = password_hash($password, PASSWORD_BCRYPT, ['cost' => 13]);
And verifying:
if (password_verify($given_password, $db_hash)) {
// password valid
}
See also: password_hash()
, password_verify()
Oracle (ORA-02270) : no matching unique or primary key for this column-list error
In my case the problem was cause by a disabled PK.
In order to enable it:
I look for the Constraint name with:
SELECT * FROM USER_CONS_COLUMNS WHERE TABLE_NAME = 'referenced_table_name';
Then I took the Constraint name in order to enable it with the following command:
ALTER TABLE table_name ENABLE CONSTRAINT constraint_name;
getting a checkbox array value from POST
Check out the implode() function as an alternative. This will convert the array into a list. The first param is how you want the items separated. Here I have used a comma with a space after it.
$invite = implode(', ', $_POST['invite']);
echo $invite;
Returning http status code from Web Api controller
For ASP.NET Web Api 2, this post from MS suggests to change the method's return type to IHttpActionResult
. You can then return a built in IHttpActionResult
implementation like Ok
, BadRequest
, etc (see here) or return your own implementation.
For your code, it could be done like:
public IHttpActionResult GetUser(int userId, DateTime lastModifiedAtClient)
{
var user = new DataEntities().Users.First(p => p.Id == userId);
if (user.LastModified <= lastModifiedAtClient)
{
return StatusCode(HttpStatusCode.NotModified);
}
return Ok(user);
}
Entity Framework code first unique column
Solution for EF4.3
Unique UserName
Add data annotation over column as:
[Index(IsUnique = true)]
[MaxLength(255)] // for code-first implementations
public string UserName{get;set;}
Unique ID
,
I have added decoration [Key] over my column and done.
Same solution as described here: https://msdn.microsoft.com/en-gb/data/jj591583.aspx
IE:
[Key]
public int UserId{get;set;}
Alternative answers
using data annotation
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Column("UserId")]
using mapping
mb.Entity<User>()
.HasKey(i => i.UserId);
mb.User<User>()
.Property(i => i.UserId)
.HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity)
.HasColumnName("UserId");
How to get Database Name from Connection String using SqlConnectionStringBuilder
this gives you the Xact;
System.Data.SqlClient.SqlConnectionStringBuilder connBuilder = new System.Data.SqlClient.SqlConnectionStringBuilder();
connBuilder.ConnectionString = connectionString;
string server = connBuilder.DataSource; //-> this gives you the Server name.
string database = connBuilder.InitialCatalog; //-> this gives you the Db name.
Symfony 2 EntityManager injection in service
For modern reference, in Symfony 2.4+, you cannot name the arguments for the Constructor Injection method anymore. According to the documentation You would pass in:
services:
test.common.userservice:
class: Test\CommonBundle\Services\UserService
arguments: [ "@doctrine.orm.entity_manager" ]
And then they would be available in the order they were listed via the arguments (if there are more than 1).
public function __construct(EntityManager $entityManager) {
$this->em = $entityManager;
}
SQL Add foreign key to existing column
In the future.
ALTER TABLE Employees
ADD UserID int;
ALTER TABLE Employees
ADD CONSTRAINT FK_ActiveDirectories_UserID FOREIGN KEY (UserID)
REFERENCES ActiveDirectories(id);
how to update the multiple rows at a time using linq to sql?
To update one column here are some syntax options:
Option 1
var ls=new int[]{2,3,4};
using (var db=new SomeDatabaseContext())
{
var some= db.SomeTable.Where(x=>ls.Contains(x.friendid)).ToList();
some.ForEach(a=>a.status=true);
db.SubmitChanges();
}
Option 2
using (var db=new SomeDatabaseContext())
{
db.SomeTable
.Where(x=>ls.Contains(x.friendid))
.ToList()
.ForEach(a=>a.status=true);
db.SubmitChanges();
}
Option 3
using (var db=new SomeDatabaseContext())
{
foreach (var some in db.SomeTable.Where(x=>ls.Contains(x.friendid)).ToList())
{
some.status=true;
}
db.SubmitChanges();
}
Update
As requested in the comment it might make sense to show how to update multiple columns. So let's say for the purpose of this exercise that we want not just to update the status
at ones. We want to update name
and status
where the friendid
is matching. Here are some syntax options for that:
Option 1
var ls=new int[]{2,3,4};
var name="Foo";
using (var db=new SomeDatabaseContext())
{
var some= db.SomeTable.Where(x=>ls.Contains(x.friendid)).ToList();
some.ForEach(a=>
{
a.status=true;
a.name=name;
}
);
db.SubmitChanges();
}
Option 2
using (var db=new SomeDatabaseContext())
{
db.SomeTable
.Where(x=>ls.Contains(x.friendid))
.ToList()
.ForEach(a=>
{
a.status=true;
a.name=name;
}
);
db.SubmitChanges();
}
Option 3
using (var db=new SomeDatabaseContext())
{
foreach (var some in db.SomeTable.Where(x=>ls.Contains(x.friendid)).ToList())
{
some.status=true;
some.name=name;
}
db.SubmitChanges();
}
Update 2
In the answer I was using LINQ to SQL and in that case to commit to the database the usage is:
db.SubmitChanges();
But for Entity Framework to commit the changes it is:
db.SaveChanges()
ALTER TABLE add constraint
ALTER TABLE `User`
ADD CONSTRAINT `user_properties_foreign`
FOREIGN KEY (`properties`)
REFERENCES `Properties` (`ID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION;
Issue with Task Scheduler launching a task
Thanks all,
I had the same issue. I have a task that runs via a generic user account not linked to a particular person. This user as somehow logged off the VM, when I was trying to fix it I was logged in as me and not that user.
Logging back in with that user fixed the issue!
How to get Map data using JDBCTemplate.queryForMap
queryForMap
is appropriate if you want to get a single row. You are selecting without a where
clause, so you probably want to queryForList
. The error is probably indicative of the fact that queryForMap
wants one row, but you query is retrieving many rows.
Check out the docs. There is a queryForList
that takes just sql; the return type is a
List<Map<String,Object>>
.
So once you have the results, you can do what you are doing. I would do something like
List results = template.queryForList(sql);
for (Map m : results){
m.get('userid');
m.get('username');
}
I'll let you fill in the details, but I would not iterate over keys in this case. I like to explicit about what I am expecting.
If you have a User
object, and you actually want to load User instances, you can use the queryForList
that takes sql and a class type
queryForList(String sql, Class<T> elementType)
(wow Spring has changed a lot since I left Javaland.)
what does "error : a nonstatic member reference must be relative to a specific object" mean?
CPMSifDlg::EncodeAndSend()
method is declared as non-static
and thus it must be called using an object of CPMSifDlg
. e.g.
CPMSifDlg obj;
return obj.EncodeAndSend(firstName, lastName, roomNumber, userId, userFirstName, userLastName);
If EncodeAndSend
doesn't use/relate any specifics of an object (i.e. this
) but general for the class CPMSifDlg
then declare it as static
:
class CPMSifDlg {
...
static int EncodeAndSend(...);
^^^^^^
};
Setting HttpContext.Current.Session in a unit test
The answer @Ro Hit gave helped me a lot, but I was missing the user credentials because I had to fake a user for authentication unit testing. Hence, let me describe how I solved it.
According to this, if you add the method
// using System.Security.Principal;
GenericPrincipal FakeUser(string userName)
{
var fakeIdentity = new GenericIdentity(userName);
var principal = new GenericPrincipal(fakeIdentity, null);
return principal;
}
and then append
HttpContext.Current.User = FakeUser("myDomain\\myUser");
to the last line of the TestSetup
method you're done, the user credentials are added and ready to be used for authentication testing.
I also noticed that there are other parts in HttpContext you might require, such as the .MapPath()
method. There is a FakeHttpContext available, which is described here and can be installed via NuGet.
Using .Select and .Where in a single LINQ statement
Did you add the Select()
after the Where()
or before?
You should add it after, because of the concurrency logic:
1 Take the entire table
2 Filter it accordingly
3 Select only the ID's
4 Make them distinct.
If you do a Select first, the Where clause can only contain the ID attribute because all other attributes have already been edited out.
Update: For clarity, this order of operators should work:
db.Items.Where(x=> x.userid == user_ID).Select(x=>x.Id).Distinct();
Probably want to add a .toList()
at the end but that's optional :)
org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing
I had a similar problem and although I made sure that referenced entities were saved first it keeps failing with the same exception.
After hours of investigation it turns out that the problem was because the "version" column of the referenced entity was NULL.
In my particular setup i was inserting it first in an HSQLDB(that was a unit test) a row like that:
INSERT INTO project VALUES (1,1,'2013-08-28 13:05:38','2013-08-28 13:05:38','aProject','aa',NULL,'bb','dd','ee','ff','gg','ii',NULL,'LEGACY','0','CREATED',NULL,NULL,1,'0',NULL,NULL,NULL,NULL,'0','0', NULL);
The problem of the above is the version column used by hibernate was set to null, so even if the object was correctly saved, Hibernate considered it as unsaved. When making sure the version had a NON-NULL(1 in this case) value the exception disappeared and everything worked fine.
I am putting it here in case someone else had the same problem, since this took me a long time to figure this out and the solution is completely different than the above.
How to select a single column with Entity Framework?
If you're fetching a single item only then, you need use select before your FirstOrDefault()/SingleOrDefault(). And you can use anonymous object of the required properties.
var name = dbContext.MyTable.Select(x => new { x.UserId, x.Name }).FirstOrDefault(x => x.UserId == 1)?.Name;
Above query will be converted to this:
Select Top (1) UserId, Name from MyTable where UserId = 1;
For multiple items you can simply chain Select after Where:
var names = dbContext.MyTable.Where(x => x.UserId > 10).Select(x => x.Name);
Use anonymous object inside Select if you need more than one properties.
Change primary key column in SQL Server
Necromancing.
It looks you have just as good a schema to work with as me...
Here is how to do it correctly:
In this example, the table name is dbo.T_SYS_Language_Forms, and the column name is LANG_UID
-- First, chech if the table exists...
IF 0 < (
SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_TYPE = 'BASE TABLE'
AND TABLE_SCHEMA = 'dbo'
AND TABLE_NAME = 'T_SYS_Language_Forms'
)
BEGIN
-- Check for NULL values in the primary-key column
IF 0 = (SELECT COUNT(*) FROM T_SYS_Language_Forms WHERE LANG_UID IS NULL)
BEGIN
ALTER TABLE T_SYS_Language_Forms ALTER COLUMN LANG_UID uniqueidentifier NOT NULL
-- No, don't drop, FK references might already exist...
-- Drop PK if exists
-- ALTER TABLE T_SYS_Language_Forms DROP CONSTRAINT pk_constraint_name
--DECLARE @pkDropCommand nvarchar(1000)
--SET @pkDropCommand = N'ALTER TABLE T_SYS_Language_Forms DROP CONSTRAINT ' + QUOTENAME((SELECT CONSTRAINT_NAME FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
--WHERE CONSTRAINT_TYPE = 'PRIMARY KEY'
--AND TABLE_SCHEMA = 'dbo'
--AND TABLE_NAME = 'T_SYS_Language_Forms'
----AND CONSTRAINT_NAME = 'PK_T_SYS_Language_Forms'
--))
---- PRINT @pkDropCommand
--EXECUTE(@pkDropCommand)
-- Instead do
-- EXEC sp_rename 'dbo.T_SYS_Language_Forms.PK_T_SYS_Language_Forms1234565', 'PK_T_SYS_Language_Forms';
-- Check if they keys are unique (it is very possible they might not be)
IF 1 >= (SELECT TOP 1 COUNT(*) AS cnt FROM T_SYS_Language_Forms GROUP BY LANG_UID ORDER BY cnt DESC)
BEGIN
-- If no Primary key for this table
IF 0 =
(
SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
WHERE CONSTRAINT_TYPE = 'PRIMARY KEY'
AND TABLE_SCHEMA = 'dbo'
AND TABLE_NAME = 'T_SYS_Language_Forms'
-- AND CONSTRAINT_NAME = 'PK_T_SYS_Language_Forms'
)
ALTER TABLE T_SYS_Language_Forms ADD CONSTRAINT PK_T_SYS_Language_Forms PRIMARY KEY CLUSTERED (LANG_UID ASC)
;
-- Adding foreign key
IF 0 = (SELECT COUNT(*) FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS WHERE CONSTRAINT_NAME = 'FK_T_ZO_SYS_Language_Forms_T_SYS_Language_Forms')
ALTER TABLE T_ZO_SYS_Language_Forms WITH NOCHECK ADD CONSTRAINT FK_T_ZO_SYS_Language_Forms_T_SYS_Language_Forms FOREIGN KEY(ZOLANG_LANG_UID) REFERENCES T_SYS_Language_Forms(LANG_UID);
END -- End uniqueness check
ELSE
PRINT 'FSCK, this column has duplicate keys, and can thus not be changed to primary key...'
END -- End NULL check
ELSE
PRINT 'FSCK, need to figure out how to update NULL value(s)...'
END
Referring to a Column Alias in a WHERE Clause
Came here looking something similar to that, but with a CASE WHEN, and ended using the where like this: WHERE (CASE WHEN COLUMN1=COLUMN2 THEN '1' ELSE '0' END) = 0
maybe you could use DATEDIFF
in the WHERE
directly.
Something like:
SELECT logcount, logUserID, maxlogtm
FROM statslogsummary
WHERE (DATEDIFF(day, maxlogtm, GETDATE())) > 120
SQL Server Group By Month
Now your query is explicitly looking at only payments for year = 2010, however, I think you meant to have your Jan/Feb/Mar actually represent 2009. If so, you'll need to adjust this a bit for that case. Don't keep requerying the sum values for every column, just the condition of the date difference in months. Put the rest in the WHERE clause.
SELECT
SUM( case when DateDiff(m, PaymentDate, @start) = 0
then Amount else 0 end ) AS "Apr",
SUM( case when DateDiff(m, PaymentDate, @start) = 1
then Amount else 0 end ) AS "May",
SUM( case when DateDiff(m, PaymentDate, @start) = 2
then Amount else 0 end ) AS "June",
SUM( case when DateDiff(m, PaymentDate, @start) = 3
then Amount else 0 end ) AS "July",
SUM( case when DateDiff(m, PaymentDate, @start) = 4
then Amount else 0 end ) AS "Aug",
SUM( case when DateDiff(m, PaymentDate, @start) = 5
then Amount else 0 end ) AS "Sep",
SUM( case when DateDiff(m, PaymentDate, @start) = 6
then Amount else 0 end ) AS "Oct",
SUM( case when DateDiff(m, PaymentDate, @start) = 7
then Amount else 0 end ) AS "Nov",
SUM( case when DateDiff(m, PaymentDate, @start) = 8
then Amount else 0 end ) AS "Dec",
SUM( case when DateDiff(m, PaymentDate, @start) = 9
then Amount else 0 end ) AS "Jan",
SUM( case when DateDiff(m, PaymentDate, @start) = 10
then Amount else 0 end ) AS "Feb",
SUM( case when DateDiff(m, PaymentDate, @start) = 11
then Amount else 0 end ) AS "Mar"
FROM
Payments I
JOIN Live L
on I.LiveID = L.Record_Key
WHERE
Year = 2010
AND UserID = 100
Create unique constraint with null columns
I think there is a semantic problem here. In my view, a user can have a (but only one) favourite recipe to prepare a specific menu. (The OP has menu and recipe mixed up; if I am wrong: please interchange MenuId and RecipeId below)
That implies that {user,menu} should be a unique key in this table. And it should point to exactly one recipe. If the user has no favourite recipe for this specific menu no row should exist for this {user,menu} key pair. Also: the surrogate key (FaVouRiteId) is superfluous: composite primary keys are perfectly valid for relational-mapping tables.
That would lead to the reduced table definition:
CREATE TABLE Favorites
( UserId uuid NOT NULL REFERENCES users(id)
, MenuId uuid NOT NULL REFERENCES menus(id)
, RecipeId uuid NOT NULL REFERENCES recipes(id)
, PRIMARY KEY (UserId, MenuId)
);
ASP.NET Setting width of DataBound column in GridView
I did a small demo for you. Demonstrating how to display long text.
In this example there is a column Name which may contain very long text. The boundField will display all content in a table cell and therefore the cell will expand as needed (because of the content)
The TemplateField will also be rendered as a cell BUT it contains a div which limits the width of any contet to eg 40px. So this column will have some kind of max-width!
<asp:GridView ID="gvPersons" runat="server" AutoGenerateColumns="False" Width="100px">
<Columns>
<asp:BoundField HeaderText="ID" DataField="ID" />
<asp:BoundField HeaderText="Name (long)" DataField="Name">
<ItemStyle Width="40px"></ItemStyle>
</asp:BoundField>
<asp:TemplateField HeaderText="Name (short)">
<ItemTemplate>
<div style="width: 40px; overflow: hidden; white-space: nowrap; text-overflow: ellipsis">
<%# Eval("Name") %>
</div>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
Here is my demo codeBehind
public partial class gridViewLongText : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
#region init and bind data
List<Person> list = new List<Person>();
list.Add(new Person(1, "Sam"));
list.Add(new Person(2, "Max"));
list.Add(new Person(3, "Dave"));
list.Add(new Person(4, "TabularasaVeryLongName"));
gvPersons.DataSource = list;
gvPersons.DataBind();
#endregion
}
}
public class Person
{
public int ID { get; set; }
public string Name { get; set; }
public Person(int _ID, string _Name)
{
ID = _ID;
Name = _Name;
}
}
SQL string value spanning multiple lines in query
What's the column "BIO" datatype? What database server (sql/oracle/mysql)?
You should be able to span over multiple lines all you want as long as you adhere to the character limit in the column's datatype (ie: varchar(200) ).
Try using single quotes, that might make a difference.
This works for me:
update table set mycolumn = 'hello world,
my name is carlos.
goodbye.'
where id = 1;
Also, you might want to put in checks for single quotes if you are concatinating the sql string together in C#. If the variable contains single quotes that could escape the code out of the sql statement, therefore, not doing all the lines you were expecting to see.
BTW, you can delimit your SQL statements with a semi colon like you do in C#, just as FYI.
How should I use try-with-resources with JDBC?
As others have stated, your code is basically correct though the outer try
is unneeded. Here are a few more thoughts.
DataSource
Other answers here are correct and good, such the accepted Answer by bpgergo. But none of the show the use of DataSource
, commonly recommended over use of DriverManager
in modern Java.
So for the sake of completeness, here is a complete example that fetches the current date from the database server. The database used here is Postgres. Any other database would work similarly. You would replace the use of org.postgresql.ds.PGSimpleDataSource
with an implementation of DataSource
appropriate to your database. An implementation is likely provided by your particular driver, or connection pool if you go that route.
A DataSource
implementation need not be closed, because it is never “opened”. A DataSource
is not a resource, is not connected to the database, so it is not holding networking connections nor resources on the database server. A DataSource
is simply information needed when making a connection to the database, with the database server's network name or address, the user name, user password, and various options you want specified when a connection is eventually made. So your DataSource
implementation object does not go inside your try-with-resources parentheses.
Nested try-with-resources
Your code makes proper used of nested try-with-resources statements.
Notice in the example code below that we also use the try-with-resources syntax twice, one nested inside the other. The outer try
defines two resources: Connection
and PreparedStatement
. The inner try
defines the ResultSet
resource. This is a common code structure.
If an exception is thrown from the inner one, and not caught there, the ResultSet
resource will automatically be closed (if it exists, is not null). Following that, the PreparedStatement
will be closed, and lastly the Connection
is closed. Resources are automatically closed in reverse order in which they were declared within the try-with-resource statements.
The example code here is overly simplistic. As written, it could be executed with a single try-with-resources statement. But in a real work you will likely be doing more work between the nested pair of try
calls. For example, you may be extracting values from your user-interface or a POJO, and then passing those to fulfill ?
placeholders within your SQL via calls to PreparedStatement::set…
methods.
Syntax notes
Trailing semicolon
Notice that the semicolon trailing the last resource statement within the parentheses of the try-with-resources is optional. I include it in my own work for two reasons: Consistency and it looks complete, and it makes copy-pasting a mix of lines easier without having to worry about end-of-line semicolons. Your IDE may flag the last semicolon as superfluous, but there is no harm in leaving it.
Java 9 – Use existing vars in try-with-resources
New in Java 9 is an enhancement to try-with-resources syntax. We can now declare and populate the resources outside the parentheses of the try
statement. I have not yet found this useful for JDBC resources, but keep it in mind in your own work.
ResultSet
should close itself, but may not
In an ideal world the ResultSet
would close itself as the documentation promises:
A ResultSet object is automatically closed when the Statement object that generated it is closed, re-executed, or used to retrieve the next result from a sequence of multiple results.
Unfortunately, in the past some JDBC drivers infamously failed to fulfill this promise. As a result, many JDBC programmers learned to explicitly close all their JDBC resources including Connection
, PreparedStatement
, and ResultSet
too. The modern try-with-resources syntax has made doing so easier, and with more compact code. Notice that the Java team went to the bother of marking ResultSet
as AutoCloseable
, and I suggest we make use of that. Using a try-with-resources around all your JDBC resources makes your code more self-documenting as to your intentions.
Code example
package work.basil.example;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.time.LocalDate;
import java.util.Objects;
public class App
{
public static void main ( String[] args )
{
App app = new App();
app.doIt();
}
private void doIt ( )
{
System.out.println( "Hello World!" );
org.postgresql.ds.PGSimpleDataSource dataSource = new org.postgresql.ds.PGSimpleDataSource();
dataSource.setServerName( "1.2.3.4" );
dataSource.setPortNumber( 5432 );
dataSource.setDatabaseName( "example_db_" );
dataSource.setUser( "scott" );
dataSource.setPassword( "tiger" );
dataSource.setApplicationName( "ExampleApp" );
System.out.println( "INFO - Attempting to connect to database: " );
if ( Objects.nonNull( dataSource ) )
{
String sql = "SELECT CURRENT_DATE ;";
try (
Connection conn = dataSource.getConnection() ;
PreparedStatement ps = conn.prepareStatement( sql ) ;
)
{
… make `PreparedStatement::set…` calls here.
try (
ResultSet rs = ps.executeQuery() ;
)
{
if ( rs.next() )
{
LocalDate ld = rs.getObject( 1 , LocalDate.class );
System.out.println( "INFO - date is " + ld );
}
}
}
catch ( SQLException e )
{
e.printStackTrace();
}
}
System.out.println( "INFO - all done." );
}
}
Insert current date into a date column using T-SQL?
To insert a new row into a given table (tblTable) :
INSERT INTO tblTable (DateColumn) VALUES (GETDATE())
To update an existing row :
UPDATE tblTable SET DateColumn = GETDATE()
WHERE ID = RequiredUpdateID
Note that when INSERT
ing a new row you will need to observe any constraints which are on the table - most likely the NOT NULL
constraint - so you may need to provide values for other columns eg...
INSERT INTO tblTable (Name, Type, DateColumn) VALUES ('John', 7, GETDATE())
get the selected index value of <select> tag in php
As you said..
$Gender = isset($_POST["gender"]); ' it returns a empty string
because, you haven't mention method type either use POST or GET, by default it will use GET method. On the other side, you are trying to retrieve your value by using POST method, but in the form you haven't mentioned POST method. Which means miss-match method will result for empty.
Try this code..
<form name="signup_form" action="./signup.php" onsubmit="return validateForm()" method="post">
<table>
<tr> <td> First Name </td><td> <input type="text" name="fname" size=10/></td></tr>
<tr> <td> Last Name </td><td> <input type="text" name="lname" size=10/></td></tr>
<tr> <td> Your Email </td><td> <input type="text" name="email" size=10/></td></tr>
<tr> <td> Re-type Email </td><td> <input type="text" name="remail"size=10/></td></tr>
<tr> <td> Password </td><td> <input type="password" name="paswod" size=10/> </td></tr>
<tr> <td> Gender </td><td> <select name="gender">
<option value="select"> Select </option>
<option value="male"> Male </option>
<option value="female"> Female </option></select></td></tr>
<tr> <td> <input type="submit" value="Sign up" id="signup"/> </td> </tr>
</table>
</form>
and on signup page
$Gender = $_POST["gender"];
i'm sure.. now, you will get the value..
Operand type clash: uniqueidentifier is incompatible with int
Sounds to me like at least one of those tables has defined UserID
as a uniqueidentifier
, not an int
. Did you check the data in each table? What does SELECT TOP 1 UserID FROM
each table yield? An int
or a GUID
?
EDIT
I think you have built a procedure based on all tables that contain a column named UserID. I think you should not have included the aspnet_Membership
table in your script, since it's not really one of "your" tables.
If you meant to design your tables around the aspnet_Membership
database, then why are the rest of the columns int
when that table clearly uses a uniqueidentifier
for the UserID
column?
Foreign key constraints: When to use ON UPDATE and ON DELETE
Do not hesitate to put constraints on the database. You'll be sure to have a consistent database, and that's one of the good reasons to use a database. Especially if you have several applications requesting it (or just one application but with a direct mode and a batch mode using different sources).
With MySQL you do not have advanced constraints like you would have in postgreSQL but at least the foreign key constraints are quite advanced.
We'll take an example, a company table with a user table containing people from theses company
CREATE TABLE COMPANY (
company_id INT NOT NULL,
company_name VARCHAR(50),
PRIMARY KEY (company_id)
) ENGINE=INNODB;
CREATE TABLE USER (
user_id INT,
user_name VARCHAR(50),
company_id INT,
INDEX company_id_idx (company_id),
FOREIGN KEY (company_id) REFERENCES COMPANY (company_id) ON...
) ENGINE=INNODB;
Let's look at the ON UPDATE clause:
- ON UPDATE RESTRICT : the default : if you try to update a company_id in table COMPANY the engine will reject the operation if one USER at least links on this company.
- ON UPDATE NO ACTION : same as RESTRICT.
- ON UPDATE CASCADE : the best one usually : if you update a company_id in a row of table COMPANY the engine will update it accordingly on all USER rows referencing this COMPANY (but no triggers activated on USER table, warning). The engine will track the changes for you, it's good.
- ON UPDATE SET NULL : if you update a company_id in a row of table COMPANY the engine will set related USERs company_id to NULL (should be available in USER company_id field). I cannot see any interesting thing to do with that on an update, but I may be wrong.
And now on the ON DELETE side:
- ON DELETE RESTRICT : the default : if you try to delete a company_id Id in table COMPANY the engine will reject the operation if one USER at least links on this company, can save your life.
- ON DELETE NO ACTION : same as RESTRICT
- ON DELETE CASCADE : dangerous : if you delete a company row in table COMPANY the engine will delete as well the related USERs. This is dangerous but can be used to make automatic cleanups on secondary tables (so it can be something you want, but quite certainly not for a COMPANY<->USER example)
- ON DELETE SET NULL : handful : if you delete a COMPANY row the related USERs will automatically have the relationship to NULL. If Null is your value for users with no company this can be a good behavior, for example maybe you need to keep the users in your application, as authors of some content, but removing the company is not a problem for you.
usually my default is: ON DELETE RESTRICT ON UPDATE CASCADE. with some ON DELETE CASCADE
for track tables (logs--not all logs--, things like that) and ON DELETE SET NULL
when the master table is a 'simple attribute' for the table containing the foreign key, like a JOB table for the USER table.
Edit
It's been a long time since I wrote that. Now I think I should add one important warning. MySQL has one big documented limitation with cascades. Cascades are not firing triggers. So if you were over confident enough in that engine to use triggers you should avoid cascades constraints.
MySQL triggers activate only for changes made to tables by SQL statements. They do not activate for changes in views, nor by changes to tables made by APIs that do not transmit SQL statements to the MySQL Server
==> See below the last edit, things are moving on this domain
Triggers are not activated by foreign key actions.
And I do not think this will get fixed one day. Foreign key constraints are managed by the InnoDb storage and Triggers are managed by the MySQL SQL engine. Both are separated. Innodb is the only storage with constraint management, maybe they'll add triggers directly in the storage engine one day, maybe not.
But I have my own opinion on which element you should choose between the poor trigger implementation and the very useful foreign keys constraints support. And once you'll get used to database consistency you'll love PostgreSQL.
12/2017-Updating this Edit about MySQL:
as stated by @IstiaqueAhmed in the comments, the situation has changed on this subject. So follow the link and check the real up-to-date situation (which may change again in the future).
How to pass datetime from c# to sql correctly?
I had many issues involving C# and SqlServer. I ended up doing the following:
- On SQL Server I use the DateTime column type
- On c# I use the .ToString("yyyy-MM-dd HH:mm:ss") method
Also make sure that all your machines run on the same timezone.
Regarding the different result sets you get, your first example is "July First" while the second is "4th of July" ...
Also, the second example can be also interpreted as "April 7th", it depends on your server localization configuration (my solution doesn't suffer from this issue).
EDIT: hh was replaced with HH, as it doesn't seem to capture the correct hour on systems with AM/PM as opposed to systems with 24h clock. See the comments below.
jQuery - Detect value change on hidden input field
Building off of Viktar's answer, here's an implementation you can call once on a given hidden input element to ensure that subsequent change events get fired whenever the value of the input element changes:
/**
* Modifies the provided hidden input so value changes to trigger events.
*
* After this method is called, any changes to the 'value' property of the
* specified input will trigger a 'change' event, just like would happen
* if the input was a text field.
*
* As explained in the following SO post, hidden inputs don't normally
* trigger on-change events because the 'blur' event is responsible for
* triggering a change event, and hidden inputs aren't focusable by virtue
* of being hidden elements:
* https://stackoverflow.com/a/17695525/4342230
*
* @param {HTMLInputElement} inputElement
* The DOM element for the hidden input element.
*/
function setupHiddenInputChangeListener(inputElement) {
const propertyName = 'value';
const {get: originalGetter, set: originalSetter} =
findPropertyDescriptor(inputElement, propertyName);
// We wrap this in a function factory to bind the getter and setter values
// so later callbacks refer to the correct object, in case we use this
// method on more than one hidden input element.
const newPropertyDescriptor = ((_originalGetter, _originalSetter) => {
return {
set: function(value) {
const currentValue = originalGetter.call(inputElement);
// Delegate the call to the original property setter
_originalSetter.call(inputElement, value);
// Only fire change if the value actually changed.
if (currentValue !== value) {
inputElement.dispatchEvent(new Event('change'));
}
},
get: function() {
// Delegate the call to the original property getter
return _originalGetter.call(inputElement);
}
}
})(originalGetter, originalSetter);
Object.defineProperty(inputElement, propertyName, newPropertyDescriptor);
};
/**
* Search the inheritance tree of an object for a property descriptor.
*
* The property descriptor defined nearest in the inheritance hierarchy to
* the class of the given object is returned first.
*
* Credit for this approach:
* https://stackoverflow.com/a/38802602/4342230
*
* @param {Object} object
* @param {String} propertyName
* The name of the property for which a descriptor is desired.
*
* @returns {PropertyDescriptor, null}
*/
function findPropertyDescriptor(object, propertyName) {
if (object === null) {
return null;
}
if (object.hasOwnProperty(propertyName)) {
return Object.getOwnPropertyDescriptor(object, propertyName);
}
else {
const parentClass = Object.getPrototypeOf(object);
return findPropertyDescriptor(parentClass, propertyName);
}
}
Call this on document ready like so:
$(document).ready(function() {
setupHiddenInputChangeListener($('myinput')[0]);
});
Append data to a POST NSURLRequest
If you don't wish to use 3rd party classes then the following is how you set the post body...
NSURL *aUrl = [NSURL URLWithString:@"http://www.apple.com/"];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:aUrl
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:60.0];
[request setHTTPMethod:@"POST"];
NSString *postString = @"company=Locassa&quality=AWESOME!";
[request setHTTPBody:[postString dataUsingEncoding:NSUTF8StringEncoding]];
NSURLConnection *connection= [[NSURLConnection alloc] initWithRequest:request
delegate:self];
Simply append your key/value pair to the post string
Object cannot be cast from DBNull to other types
Reason for the error: In an object-oriented programming language, null means the absence of a reference to an object. DBNull represents an uninitialized variant or nonexistent database column. Source:MSDN
Actual Code which I faced error:
Before changed the code:
if( ds.Tables[0].Rows[0][0] == null ) // Which is not working
{
seqno = 1;
}
else
{
seqno = Convert.ToInt16(ds.Tables[0].Rows[0][0]) + 1;
}
After changed the code:
if( ds.Tables[0].Rows[0][0] == DBNull.Value ) //which is working properly
{
seqno = 1;
}
else
{
seqno = Convert.ToInt16(ds.Tables[0].Rows[0][0]) + 1;
}
Conclusion: when the database value return the null value, we recommend to use the DBNull class instead of just specifying as a null like in C# language.
Can we pass an array as parameter in any function in PHP?
I composed this code as an example. Hope the idea works!
<?php
$friends = array('Robert', 'Louis', 'Ferdinand');
function greetings($friends){
echo "Greetings, $friends <br>";
}
foreach ($friends as $friend) {
greetings($friend);
}
?>
MySQL integer field is returned as string in PHP
This happens when PDO::ATTR_EMULATE_PREPARES
is set to true
on the connection.
Careful though, setting it to false
disallows the use of parameters more than once. I believe it also affects the quality of the error messages coming back.
Index (zero based) must be greater than or equal to zero
This can also happen when trying to throw an ArgumentException
where you inadvertently call the ArgumentException
constructor overload
public static void Dostuff(Foo bar)
{
// this works
throw new ArgumentException(String.Format("Could not find {0}", bar.SomeStringProperty));
//this gives the error
throw new ArgumentException(String.Format("Could not find {0}"), bar.SomeStringProperty);
}
How to get the groups of a user in Active Directory? (c#, asp.net)
My solution:
UserPrincipal user = UserPrincipal.FindByIdentity(new PrincipalContext(ContextType.Domain, myDomain), IdentityType.SamAccountName, myUser);
List<string> UserADGroups = new List<string>();
foreach (GroupPrincipal group in user.GetGroups())
{
UserADGroups.Add(group.ToString());
}
How to get last inserted id?
string insertSql =
"INSERT INTO aspnet_GameProfiles(UserId,GameId) VALUES(@UserId, @GameId)SELECT SCOPE_IDENTITY()";
int primaryKey;
using (SqlConnection myConnection = new SqlConnection(myConnectionString))
{
myConnection.Open();
SqlCommand myCommand = new SqlCommand(insertSql, myConnection);
myCommand.Parameters.AddWithValue("@UserId", newUserId);
myCommand.Parameters.AddWithValue("@GameId", newGameId);
primaryKey = Convert.ToInt32(myCommand.ExecuteScalar());
myConnection.Close();
}
This will work.
MySQL Insert into multiple tables? (Database normalization?)
try this
$sql= " INSERT INTO users (username, password) VALUES('test', 'test') ";
mysql_query($sql);
$user_id= mysql_insert_id();
if(!empty($user_id) {
$sql=INSERT INTO profiles (userid, bio, homepage) VALUES($user_id,'Hello world!', 'http://www.stackoverflow.com');
/* or
$sql=INSERT INTO profiles (userid, bio, homepage) VALUES(LAST_INSERT_ID(),'Hello world!', 'http://www.stackoverflow.com'); */
mysql_query($sql);
};
References
PHP
MYSQL
Mapping many-to-many association table with extra column(s)
As said before, with JPA, in order to have the chance to have extra columns, you need to use two OneToMany associations, instead of a single ManyToMany relationship.
You can also add a column with autogenerated values; this way, it can work as the primary key of the table, if useful.
For instance, the implementation code of the extra class should look like that:
@Entity
@Table(name = "USER_SERVICES")
public class UserService{
// example of auto-generated ID
@Id
@Column(name = "USER_SERVICES_ID", nullable = false)
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long userServiceID;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "USER_ID")
private User user;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "SERVICE_ID")
private Service service;
// example of extra column
@Column(name="VISIBILITY")
private boolean visibility;
public long getUserServiceID() {
return userServiceID;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public Service getService() {
return service;
}
public void setService(Service service) {
this.service = service;
}
public boolean getVisibility() {
return visibility;
}
public void setVisibility(boolean visibility) {
this.visibility = visibility;
}
}
DataGrid get selected rows' column values
DataGrid get selected rows' column values it can be access by below code. Here grid1 is name of Gride.
private void Edit_Click(object sender, RoutedEventArgs e)
{
DataRowView rowview = grid1.SelectedItem as DataRowView;
string id = rowview.Row[0].ToString();
}
Cannot add or update a child row: a foreign key constraint fails
I just had the same problem the solution is easy.
You are trying to add an id in the child table that does not exist in the parent table.
check well, because InnoDB has the bug that sometimes increases the auto_increment column without adding values, for example, INSERT ... ON DUPLICATE KEY
PostgreSQL Exception Handling
Use the DO statement, a new option in version 9.0:
DO LANGUAGE plpgsql
$$
BEGIN
CREATE TABLE "Logs"."Events"
(
EventId BIGSERIAL NOT NULL PRIMARY KEY,
PrimaryKeyId bigint NOT NULL,
EventDateTime date NOT NULL DEFAULT(now()),
Action varchar(12) NOT NULL,
UserId integer NOT NULL REFERENCES "Office"."Users"(UserId),
PrincipalUserId varchar(50) NOT NULL DEFAULT(user)
);
CREATE TABLE "Logs"."EventDetails"
(
EventDetailId BIGSERIAL NOT NULL PRIMARY KEY,
EventId bigint NOT NULL REFERENCES "Logs"."Events"(EventId),
Resource varchar(64) NOT NULL,
OldVal varchar(4000) NOT NULL,
NewVal varchar(4000) NOT NULL
);
RAISE NOTICE 'Task completed sucessfully.';
END;
$$;
Visual studio equivalent of java System.out
Try: Console.WriteLine
(type out
for a Visual Studio snippet)
Console.WriteLine(stuff);
Another way is to use System.Diagnostics.Debug.WriteLine
:
System.Diagnostics.Debug.WriteLine(stuff);
Debug.WriteLine
may suit better for Output window in IDE because it will be rendered for both Console and Windows applications. Whereas Console.WriteLine
won't be rendered in Output window but only in the Console itself in case of Console Application type.
Another difference is that Debug.WriteLine
will not print anything in Release configuration.
How to create a property for a List<T>
T
must be defined within the scope in which you are working. Therefore, what you have posted will work if your class is generic on T
:
public class MyClass<T>
{
private List<T> newList;
public List<T> NewList
{
get{return newList;}
set{newList = value;}
}
}
Otherwise, you have to use a defined type.
EDIT: Per @lKashef's request, following is how to have a List property:
private List<int> newList;
public List<int> NewList
{
get{return newList;}
set{newList = value;}
}
This can go within a non-generic class.
Edit 2:
In response to your second question (in your edit), I would not recommend using a list for this type of data handling (if I am understanding you correctly). I would put the user settings in their own class (or struct, if you wish) and have a property of this type on your original class:
public class UserSettings
{
string FirstName { get; set; }
string LastName { get; set; }
// etc.
}
public class MyClass
{
string MyClassProperty1 { get; set; }
// etc.
UserSettings MySettings { get; set; }
}
This way, you have named properties that you can reference instead of an arbitrary index in a list. For example, you can reference MySettings.FirstName
as opposed to MySettingsList[0]
.
Let me know if you have any further questions.
EDIT 3:
For the question in the comments, your property would be like this:
public class MyClass
{
public List<KeyValuePair<string, string>> MySettings { get; set; }
}
EDIT 4: Based on the question's edit 2, following is how I would use this:
public class MyClass
{
// note that this type of property declaration is called an "Automatic Property" and
// it means the same thing as you had written (the private backing variable is used behind the scenes, but you don't see it)
public List<KeyValuePair<string, string> MySettings { get; set; }
}
public class MyConsumingClass
{
public void MyMethod
{
MyClass myClass = new MyClass();
myClass.MySettings = new List<KeyValuePair<string, string>>();
myClass.MySettings.Add(new KeyValuePair<string, string>("SomeKeyValue", "SomeValue"));
// etc.
}
}
You mentioned that "the property still won't appear in the object's instance," and I am not sure what you mean. Does this property not appear in IntelliSense? Are you sure that you have created an instance of MyClass
(like myClass.MySettings
above), or are you trying to access it like a static property (like MyClass.MySettings
)?
Python variables as keys to dict
why you don't do the opposite :
fruitdict = {
'apple':1,
'banana':'f',
'carrot':3,
}
locals().update(fruitdict)
Update :
don't use the code above check the comment.
by the way why you don't mark the vars that you want to get i don't know
maybe like this:
# All the vars that i want to get are followed by _fruit
apple_fruit = 1
carrot_fruit = 'f'
for var in locals():
if var.endswith('fruit'):
you_dict.update({var:locals()[var])
Stop executing further code in Java
Either return;
from the method early, or throw
an exception.
There is no other way to prevent further code from being executed short of exiting the process completely.
converting json to string in python
json.dumps()
is much more than just making a string out of a Python object, it would always produce a valid JSON string (assuming everything inside the object is serializable) following the Type Conversion Table.
For instance, if one of the values is None
, the str()
would produce an invalid JSON which cannot be loaded:
>>> data = {'jsonKey': None}
>>> str(data)
"{'jsonKey': None}"
>>> json.loads(str(data))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 338, in loads
return _default_decoder.decode(s)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 366, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 382, in raw_decode
obj, end = self.scan_once(s, idx)
ValueError: Expecting property name: line 1 column 2 (char 1)
But the dumps()
would convert None
into null
making a valid JSON string that can be loaded:
>>> import json
>>> data = {'jsonKey': None}
>>> json.dumps(data)
'{"jsonKey": null}'
>>> json.loads(json.dumps(data))
{u'jsonKey': None}
How to use breakpoints in Eclipse
Put breakpoints - double click on the margin.
Run > Debug > Yes (if dialog appears), then use commands from Run menu or shortcuts - F5, F6, F7, F8.
Getting "unixtime" in Java
Java 8 added a new API for working with dates and times.
With Java 8 you can use
import java.time.Instant
...
long unixTimestamp = Instant.now().getEpochSecond();
Instant.now()
returns an Instant that represents the current system time. With getEpochSecond()
you get the epoch seconds (unix time) from the Instant
.
Relative frequencies / proportions with dplyr
Try this:
mtcars %>%
group_by(am, gear) %>%
summarise(n = n()) %>%
mutate(freq = n / sum(n))
# am gear n freq
# 1 0 3 15 0.7894737
# 2 0 4 4 0.2105263
# 3 1 4 8 0.6153846
# 4 1 5 5 0.3846154
From the dplyr vignette:
When you group by multiple variables, each summary peels off one level of the grouping. That makes it easy to progressively roll-up a dataset.
Thus, after the summarise
, the last grouping variable specified in group_by
, 'gear', is peeled off. In the mutate
step, the data is grouped by the remaining grouping variable(s), here 'am'. You may check grouping in each step with groups
.
The outcome of the peeling is of course dependent of the order of the grouping variables in the group_by
call. You may wish to do a subsequent group_by(am)
, to make your code more explicit.
For rounding and prettification, please refer to the nice answer by @Tyler Rinker.
C#: How do you edit items and subitems in a listview?
If you're looking for "in-place" editing of a ListView
's contents (specifically the subitems of a ListView in details view mode), you'll need to implement this yourself, or use a third-party control.
By default, the best you can achieve with a "standard" ListView
is to set it's LabelEdit
property to true to allow the user to edit the text of the first column of the ListView
(assuming you want to allow a free-format text edit).
Some examples (including full source-code) of customized ListView
's that allow "in-place" editing of sub-items are:
C# Editable ListView
In-place editing of ListView subitems
"VT-x is not available" when I start my Virtual machine
You might try reducing your base memory under settings to around 3175MB and reduce your cores to 1. That should work given that your BIOS is set for virtualization. Use the f12 key, security, virtualization to make sure that it is enabled. If it doesn't say VT-x that is ok, it should say VT-d or the like.
How to set label size in Bootstrap
In Bootstrap 3 they do not have separate classes for different styles of labels.
http://getbootstrap.com/components/
However, you can customize bootstrap classes that way. In your css file
.lb-sm {
font-size: 12px;
}
.lb-md {
font-size: 16px;
}
.lb-lg {
font-size: 20px;
}
Alternatively, you can use header tags to change the sizes. For example, here is a medium sized label and a small-sized label
_x000D_
_x000D_
<link href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
<h3>Example heading <span class="label label-default">New</span></h3>_x000D_
<h6>Example heading <span class="label label-default">New</span></h6>
_x000D_
_x000D_
_x000D_
They might add size classes for labels in future Bootstrap versions.
Jquery, set value of td in a table?
From:
it could be:
.html()
In an HTML document, .html()
can be used to get the contents of any element.
.text()
Unlike the .html()
method, .text()
can be used in both XML and HTML documents. The result of the .text()
method is a string containing the combined text of all matched elements.
.val()
The .val()
method is primarily used to get the values of form elements such as input
, select
and textarea
. When called on an empty collection, it returns undefined
.
Convert a python dict to a string and back
Convert dictionary into JSON (string)
import json
mydict = { "name" : "Don",
"surname" : "Mandol",
"age" : 43}
result = json.dumps(mydict)
print(result[0:20])
will get you:
{"name": "Don", "sur
Convert string into dictionary
back_to_mydict = json.loads(result)
What is ViewModel in MVC?
View model is same as your datamodel but you can add 2 or more data model classes in it. According to that you have to change your controller to take 2 models at once
How do you set up use HttpOnly cookies in PHP
You can use this in a header file.
// setup session enviroment
ini_set('session.cookie_httponly',1);
ini_set('session.use_only_cookies',1);
This way all future session cookies will use httponly.
How do I change JPanel inside a JFrame on the fly?
I suggest you to add both panel at frame creation, then change the visible panel by calling setVisible(true/false) on both.
When calling setVisible, the parent will be notified and asked to repaint itself.
How can I get LINQ to return the object which has the max value for a given property?
In case you don't want to use MoreLINQ and want to get linear time, you can also use Aggregate
:
var maxItem =
items.Aggregate(
new { Max = Int32.MinValue, Item = (Item)null },
(state, el) => (el.ID > state.Max)
? new { Max = el.ID, Item = el } : state).Item;
This remembers the current maximal element (Item
) and the current maximal value (Item
) in an anonymous type. Then you just pick the Item
property. This is indeed a bit ugly and you could wrap it into MaxBy
extension method to get the same thing as with MoreLINQ:
public static T MaxBy(this IEnumerable<T> items, Func<T, int> f) {
return items.Aggregate(
new { Max = Int32.MinValue, Item = default(T) },
(state, el) => {
var current = f(el.ID);
if (current > state.Max)
return new { Max = current, Item = el };
else
return state;
}).Item;
}
Different between parseInt() and valueOf() in java?
- In case of ValueOf -> it is creating an Integer object. not a primitive type and not a static method.
- In case of ParseInt.ParseFloat -> it return respective primitive type. and is a static method.
We should use any one depending upon our need. In case of ValueOf as it is instantiating an object. it will consume more resources if we only need value of some text then we should use parseInt,parseFloat etc.
Cropping an UIImage
Best solution for cropping an UIImage in Swift, in term of precision, pixels scaling ...:
private func squareCropImageToSideLength(let sourceImage: UIImage,
let sideLength: CGFloat) -> UIImage {
// input size comes from image
let inputSize: CGSize = sourceImage.size
// round up side length to avoid fractional output size
let sideLength: CGFloat = ceil(sideLength)
// output size has sideLength for both dimensions
let outputSize: CGSize = CGSizeMake(sideLength, sideLength)
// calculate scale so that smaller dimension fits sideLength
let scale: CGFloat = max(sideLength / inputSize.width,
sideLength / inputSize.height)
// scaling the image with this scale results in this output size
let scaledInputSize: CGSize = CGSizeMake(inputSize.width * scale,
inputSize.height * scale)
// determine point in center of "canvas"
let center: CGPoint = CGPointMake(outputSize.width/2.0,
outputSize.height/2.0)
// calculate drawing rect relative to output Size
let outputRect: CGRect = CGRectMake(center.x - scaledInputSize.width/2.0,
center.y - scaledInputSize.height/2.0,
scaledInputSize.width,
scaledInputSize.height)
// begin a new bitmap context, scale 0 takes display scale
UIGraphicsBeginImageContextWithOptions(outputSize, true, 0)
// optional: set the interpolation quality.
// For this you need to grab the underlying CGContext
let ctx: CGContextRef = UIGraphicsGetCurrentContext()
CGContextSetInterpolationQuality(ctx, kCGInterpolationHigh)
// draw the source image into the calculated rect
sourceImage.drawInRect(outputRect)
// create new image from bitmap context
let outImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()
// clean up
UIGraphicsEndImageContext()
// pass back new image
return outImage
}
Instructions used to call this function:
let image: UIImage = UIImage(named: "Image.jpg")!
let squareImage: UIImage = self.squareCropImageToSideLength(image, sideLength: 320)
self.myUIImageView.image = squareImage
Note: the initial source code inspiration written in Objective-C has been found on "Cocoanetics" blog.
How to receive serial data using android bluetooth
The issue with the null connection is related to the findBT() function. you must change the device name from "MattsBlueTooth" to your device name as well as confirm the UUID for your service/device. Use something like BLEScanner app to confrim both on Android.
What's the most concise way to read query parameters in AngularJS?
Good that you've managed to get it working with the html5 mode but it is also possible to make it work in the hashbang mode.
You could simply use:
$location.search().target
to get access to the 'target' search param.
For the reference, here is the working jsFiddle: http://web.archive.org/web/20130317065234/http://jsfiddle.net/PHnLb/7/
_x000D_
_x000D_
var myApp = angular.module('myApp', []);_x000D_
_x000D_
function MyCtrl($scope, $location) {_x000D_
_x000D_
$scope.location = $location;_x000D_
$scope.$watch('location.search()', function() {_x000D_
$scope.target = ($location.search()).target;_x000D_
}, true);_x000D_
_x000D_
$scope.changeTarget = function(name) {_x000D_
$location.search('target', name);_x000D_
}_x000D_
}
_x000D_
<div ng-controller="MyCtrl">_x000D_
_x000D_
<a href="#!/test/?target=Bob">Bob</a>_x000D_
<a href="#!/test/?target=Paul">Paul</a>_x000D_
_x000D_
<hr/> _x000D_
URL 'target' param getter: {{target}}<br>_x000D_
Full url: {{location.absUrl()}}_x000D_
<hr/>_x000D_
_x000D_
<button ng-click="changeTarget('Pawel')">target=Pawel</button>_x000D_
_x000D_
</div>
_x000D_
_x000D_
_x000D_
Use multiple custom fonts using @font-face?
You simply add another @font-face
rule:
@font-face {
font-family: CustomFont;
src: url('CustomFont.ttf');
}
@font-face {
font-family: CustomFont2;
src: url('CustomFont2.ttf');
}
If your second font still doesn't work, make sure you're spelling its typeface name and its file name correctly, your browser caches are behaving, your OS isn't messing around with a font of the same name, etc.
How to get exception message in Python properly
I too had the same problem. Digging into this I found that the Exception class has an args
attribute, which captures the arguments that were used to create the exception. If you narrow the exceptions that except will catch to a subset, you should be able to determine how they were constructed, and thus which argument contains the message.
try:
# do something that may raise an AuthException
except AuthException as ex:
if ex.args[0] == "Authentication Timeout.":
# handle timeout
else:
# generic handling
What is the boundary in multipart/form-data?
multipart/form-data contains boundary to separate name/value pairs. The boundary acts like a marker of each chunk of name/value pairs passed when a form gets submitted. The boundary is automatically added to a content-type of a request header.
The form with enctype="multipart/form-data" attribute will have a request header Content-Type : multipart/form-data; boundary --- WebKit193844043-h (browser generated vaue).
The payload passed looks something like this:
Content-Type: multipart/form-data; boundary=---WebKitFormBoundary7MA4YWxkTrZu0gW
-----WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name=”file”; filename=”captcha”
Content-Type:
-----WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name=”action”
submit
-----WebKitFormBoundary7MA4YWxkTrZu0gW--
On the webservice side, it's consumed in @Consumes("multipart/form-data") form.
Beware, when testing your webservice using chrome postman, you need to check the form data option(radio button) and File menu from the dropdown box to send attachment. Explicit provision of content-type as multipart/form-data throws an error. Because boundary is missing as it overrides the curl request of post man to server with content-type by appending the boundary which works fine.
See RFC1341 sec7.2 The Multipart Content-Type
Convert Python dict into a dataframe
As explained on another answer using pandas.DataFrame()
directly here will not act as you think.
What you can do is use pandas.DataFrame.from_dict
with orient='index'
:
In[7]: pandas.DataFrame.from_dict({u'2012-06-08': 388,
u'2012-06-09': 388,
u'2012-06-10': 388,
u'2012-06-11': 389,
u'2012-06-12': 389,
.....
u'2012-07-05': 392,
u'2012-07-06': 392}, orient='index', columns=['foo'])
Out[7]:
foo
2012-06-08 388
2012-06-09 388
2012-06-10 388
2012-06-11 389
2012-06-12 389
........
2012-07-05 392
2012-07-06 392
How to write a confusion matrix in Python?
This function creates confusion matrices for any number of classes.
def create_conf_matrix(expected, predicted, n_classes):
m = [[0] * n_classes for i in range(n_classes)]
for pred, exp in zip(predicted, expected):
m[pred][exp] += 1
return m
def calc_accuracy(conf_matrix):
t = sum(sum(l) for l in conf_matrix)
return sum(conf_matrix[i][i] for i in range(len(conf_matrix))) / t
In contrast to your function above, you have to extract the predicted classes before calling the function, based on your classification results, i.e. sth. like
[1 if p < .5 else 2 for p in classifications]
Using a BOOL property
There's no benefit to using properties with primitive types. @property
is used with heap allocated NSObjects
like NSString*
, NSNumber*
, UIButton*
, and etc, because memory managed accessors are created for free. When you create a BOOL
, the value is always allocated on the stack and does not require any special accessors to prevent memory leakage. isWorking
is simply the popular way of expressing the state of a boolean value.
In another OO language you would make a variable private bool working;
and two accessors: SetWorking
for the setter and IsWorking
for the accessor.
javascript getting my textbox to display a variable
_x000D_
_x000D_
function myfunction() {_x000D_
var first = document.getElementById("textbox1").value;_x000D_
var second = document.getElementById("textbox2").value;_x000D_
var answer = parseFloat(first) + parseFloat(second);_x000D_
_x000D_
var textbox3 = document.getElementById('textbox3');_x000D_
textbox3.value = answer;_x000D_
}
_x000D_
<input type="text" name="textbox1" id="textbox1" /> + <input type="text" name="textbox2" id="textbox2" />_x000D_
<input type="submit" name="button" id="button1" onclick="myfunction()" value="=" />_x000D_
<br/> Your answer is:--_x000D_
<input type="text" name="textbox3" id="textbox3" readonly="true" />
_x000D_
_x000D_
_x000D_
AttributeError: 'module' object has no attribute 'urlretrieve'
Suppose you have following lines of code
MyUrl = "www.google.com" #Your url goes here
urllib.urlretrieve(MyUrl)
If you are receiving following error message
AttributeError: module 'urllib' has no attribute 'urlretrieve'
Then you should try following code to fix the issue:
import urllib.request
MyUrl = "www.google.com" #Your url goes here
urllib.request.urlretrieve(MyUrl)
If (Array.Length == 0)
You can use
if (array == null || array.Length == 0)
OR
if (!(array != null && array.Length != 0))
NOTE!!!!! To insure that c# will implement the short circuit correctly; you have to compare that the object with NULL before you go to the children compare of the object.
C# 7.0 and above
if(!(array?.Length != 0))
Python: Open file in zip without temporarily extracting it
Vincent Povirk's answer won't work completely;
import zipfile
archive = zipfile.ZipFile('images.zip', 'r')
imgfile = archive.open('img_01.png')
...
You have to change it in:
import zipfile
archive = zipfile.ZipFile('images.zip', 'r')
imgdata = archive.read('img_01.png')
...
For details read the ZipFile
docs here.
Measuring the distance between two coordinates in PHP
Try this function out to calculate distance between to points of latitude and longitude
function calculateDistanceBetweenTwoPoints($latitudeOne='', $longitudeOne='', $latitudeTwo='', $longitudeTwo='',$distanceUnit ='',$round=false,$decimalPoints='')
{
if (empty($decimalPoints))
{
$decimalPoints = '3';
}
if (empty($distanceUnit)) {
$distanceUnit = 'KM';
}
$distanceUnit = strtolower($distanceUnit);
$pointDifference = $longitudeOne - $longitudeTwo;
$toSin = (sin(deg2rad($latitudeOne)) * sin(deg2rad($latitudeTwo))) + (cos(deg2rad($latitudeOne)) * cos(deg2rad($latitudeTwo)) * cos(deg2rad($pointDifference)));
$toAcos = acos($toSin);
$toRad2Deg = rad2deg($toAcos);
$toMiles = $toRad2Deg * 60 * 1.1515;
$toKilometers = $toMiles * 1.609344;
$toNauticalMiles = $toMiles * 0.8684;
$toMeters = $toKilometers * 1000;
$toFeets = $toMiles * 5280;
$toYards = $toFeets / 3;
switch (strtoupper($distanceUnit))
{
case 'ML'://miles
$toMiles = ($round == true ? round($toMiles) : round($toMiles, $decimalPoints));
return $toMiles;
break;
case 'KM'://Kilometers
$toKilometers = ($round == true ? round($toKilometers) : round($toKilometers, $decimalPoints));
return $toKilometers;
break;
case 'MT'://Meters
$toMeters = ($round == true ? round($toMeters) : round($toMeters, $decimalPoints));
return $toMeters;
break;
case 'FT'://feets
$toFeets = ($round == true ? round($toFeets) : round($toFeets, $decimalPoints));
return $toFeets;
break;
case 'YD'://yards
$toYards = ($round == true ? round($toYards) : round($toYards, $decimalPoints));
return $toYards;
break;
case 'NM'://Nautical miles
$toNauticalMiles = ($round == true ? round($toNauticalMiles) : round($toNauticalMiles, $decimalPoints));
return $toNauticalMiles;
break;
}
}
Then use the fucntion as
echo calculateDistanceBetweenTwoPoints('11.657740','77.766270','11.074820','77.002160','ML',true,5);
Hope it helps
Differences between Emacs and Vim
In your question, you haven't mentioned that you want it to program in Lisp! But as you have been commenting your answers, I have understood that you actually want a LISP programming interface.
For that precise task, simply forget about Vi. Emacs integration with LISP is wonderful! You should use SLIME. You will then have wonderful integration with the REPL, being able to eval
functions, buffers or files directly into a running interpreter in an emacs buffer and much more...
How to verify if a file exists in a batch file?
You can use IF EXIST to check for a file:
IF EXIST "filename" (
REM Do one thing
) ELSE (
REM Do another thing
)
If you do not need an "else", you can do something like this:
set __myVariable=
IF EXIST "C:\folder with space\myfile.txt" set __myVariable=C:\folder with space\myfile.txt
IF EXIST "C:\some other folder with space\myfile.txt" set __myVariable=C:\some other folder with space\myfile.txt
set __myVariable=
Here's a working example of searching for a file or a folder:
REM setup
echo "some text" > filename
mkdir "foldername"
REM finds file
IF EXIST "filename" (
ECHO file filename exists
) ELSE (
ECHO file filename does not exist
)
REM does not find file
IF EXIST "filename2.txt" (
ECHO file filename2.txt exists
) ELSE (
ECHO file filename2.txt does not exist
)
REM folders must have a trailing backslash
REM finds folder
IF EXIST "foldername\" (
ECHO folder foldername exists
) ELSE (
ECHO folder foldername does not exist
)
REM does not find folder
IF EXIST "filename\" (
ECHO folder filename exists
) ELSE (
ECHO folder filename does not exist
)
Iterating over and deleting from Hashtable in Java
You can use Enumeration
:
Hashtable<Integer, String> table = ...
Enumeration<Integer> enumKey = table.keys();
while(enumKey.hasMoreElements()) {
Integer key = enumKey.nextElement();
String val = table.get(key);
if(key==0 && val.equals("0"))
table.remove(key);
}
Illegal string offset Warning PHP
I solved this problem by using trim() function. the issue was with space.
so lets try
$unit_size = []; //please declare the variable type
$unit_size = exolode("x", $unit_size);
$width = trim ($unit_size[1] );
$height = trim ($unit_size[2] );
I hope this will help you.
What exactly is \r in C language?
Once upon a time, people had terminals like typewriters (with only upper-case letters, but that's another story). Search for 'Teletype', and how do you think tty
got used for 'terminal device'?
Those devices had two separate motions. The carriage return moved the print head back to the start of the line without scrolling the paper; the line feed character moved the paper up a line without moving the print head back to the beginning of the line. So, on those devices, you needed two control characters to get the print head back to the start of the next line: a carriage return and a line feed. Because this was mechanical, it took time, so you had to pause for long enough before sending more characters to the terminal after sending the CR and LF characters. One use for CR without LF was to do 'bold' by overstriking the characters on the line. You'd write the line out once, then use CR to start over and print twice over the characters that needed to be bold. You could also, of course, type X's over stuff that you wanted partially hidden, or create very dense ASCII art pictures with judicious overstriking.
On Unix, all the logic for this stuff was hidden in a terminal driver. You could use the stty
command and the underlying functions (in those days, ioctl()
calls; they were sanitized into the termios
interface by POSIX.1 in 1988) to tweak all sorts of ways that the terminal behaved.
Eventually, you got 'glass terminals' where the speeds were greater and and there were new idiosyncrasies to deal with - Hazeltine glitches and so on and so forth. These got enshrined in the termcap
and later terminfo
libraries, and then further encapsulated behind the curses
library.
However, some other (non-Unix) systems did not hide things as well, and you had to deal with CRLF in your text files - and no, this is not just Windows and DOS that were in the 'CRLF' camp.
Anyway, on some systems, the C library has to deal with text files that contain CRLF line endings and presents those to you as if there were only a newline at the end of the line. However, if you choose to treat the text file as a binary file, you will see the CR characters as well as the LF.
Systems like the old Mac OS (version 9 or earlier) used just CR (aka \r
) for the line ending. Systems like DOS and Windows (and, I believe, many of the DEC systems such as VMS and RSTS) used CRLF for the line ending. Many of the Internet standards (such as mail) mandate CRLF line endings. And Unix has always used just LF (aka NL or newline, hence \n
) for its line endings. And most people, most of the time, manage to ignore CR.
Your code is rather funky in looking for \r
. On a system compliant with the C standard, you won't see the CR unless the file is opened in binary mode; the CRLF or CR will be mapped to NL by the C runtime library.
HTML Button : Navigate to Other Page - Different Approaches
I make a link. A link is a link. A link navigates to another page. That is what links are for and everybody understands that. So Method 3 is the only correct method in my book.
I wouldn't want my link to look like a button at all, and when I do, I still think functionality is more important than looks.
Buttons are less accessible, not only due to the need of Javascript, but also because tools for the visually impaired may not understand this Javascript enhanced button well.
Method 4 would work as well, but it is more a trick than a real functionality. You abuse a form to post 'nothing' to this other page. It's not clean.
Single huge .css file vs. multiple smaller specific .css files?
Maybe take a look at compass, which is an open source CSS authoring framework.
It's based on Sass so it supports cool things like variables, nesting, mixins and imports. Especially imports are useful if you want to keep seperate smaller CSS files but have them combined into 1 automatically (avoiding multiple slow HTTP calls).
Compass adds to this a big set of pre-defined mixins that are easy for handling cross-browser stuff.
It's written in Ruby but it can easily be used with any system....
Get a particular cell value from HTML table using JavaScript
function Vcount() {
var modify = document.getElementById("C_name1").value;
var oTable = document.getElementById('dataTable');
var i;
var rowLength = oTable.rows.length;
for (i = 1; i < rowLength; i++) {
var oCells = oTable.rows.item(i).cells;
if (modify == oCells[0].firstChild.data) {
document.getElementById("Error").innerHTML = " * duplicate value";
return false;
break;
}
}
html cellpadding the left side of a cell
I choose to use both methods. Cellpadding on the table as a fallback in case the inline style doesn't stick and inline style for most clients.
_x000D_
_x000D_
<table cellpadding="5">_x000D_
<tr>_x000D_
<td style='padding:5px 10px 5px 5px'>Content</td>_x000D_
<td style='padding:5px 10px 5px 5px'>Content</td>_x000D_
</tr>_x000D_
</table>
_x000D_
_x000D_
_x000D_
How to check if a key exists in Json Object and get its value
Try
private boolean hasKey(JSONObject jsonObject, String key) {
return jsonObject != null && jsonObject.has(key);
}
try {
JSONObject jsonObject = new JSONObject(yourJson);
if (hasKey(jsonObject, "labelData")) {
JSONObject labelDataJson = jsonObject.getJSONObject("LabelData");
if (hasKey(labelDataJson, "video")) {
String video = labelDataJson.getString("video");
}
}
} catch (JSONException e) {
}
Submit button not working in Bootstrap form
Replace this
<button type="button" value=" Send" class="btn btn-success" type="submit" id="submit">
with
<button value=" Send" class="btn btn-success" type="submit" id="submit">
How can I select from list of values in SQL Server
If it is a list of parameters from existing SQL table, for example ID list from existing Table1, then you can try this:
select distinct ID
FROM Table1
where
ID in (1, 1, 1, 2, 5, 1, 6)
ORDER BY ID;
Or, if you need List of parameters as a SQL Table constant(variable), try this:
WITH Id_list AS (
select ID
FROM Table1
where
ID in (1, 1, 1, 2, 5, 1, 6)
)
SELECT distinct * FROM Id_list
ORDER BY ID;
Not able to launch IE browser using Selenium2 (Webdriver) with Java
To resolve this issue you have to do two things :
You will need to set a registry entry on the target computer so that
the driver can maintain a connection to the instance of Internet
Explorer it creates.
Change few settings of Internet Explorer browser on that machine
(where you desire to run automation).
1 . Setting Registry Key / Entry :
To set registry key or entry, you need to open "Registry Editor".
To open "Registry Editor" press windows button key + r alphabet key
which will open "Run Window" and then type "regedit" and press enter.
Or Press Windows button key and enter "regedit" at start menu and
press enter. Now depending upon your OS type whether 32/64 bit follow
the corresponding steps.
Windows 32 bit :
go to this location - "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl" and check for "FEATURE_BFCACHE" key.
Windows 64 bit :
go to this location - HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\Main\FeatureControl and check for "FEATURE_BFCACHE" key.
Please note that the FEATURE_BFCACHE subkey may or may not be present, and should be created if it is not present.
Important: Inside this key, create a DWORD value named iexplore.exe with the value of 0.
2 . Change Settings of Internet Explorer Browser :
Click on setting button and select "Internet options".
On "Internet options" window go to "Security" tab
Now select "Internet" option and unchecked the "Enable Protected Mode" check box and change the "Security level" to low.
Now select "Local Intranet" Option and change the "Security level" to low.
Now select "Trusted Sites" Option and change the "Security level" to low.
- Now click on "Apply" button , a warning pop up may appear click on "OK" button for warning and then on "OK" button on Internet Options window.
- After this restart the browser.
Selected tab's color in Bottom Navigation View
1. Inside res create folder with name color (like drawable)
2. Right click on color folder. Select
new-> color resource file-> create color.xml file (bnv_tab_item_foreground)
(Figure 1: File Structure)
3. Copy and paste bnv_tab_item_foreground
<android.support.design.widget.BottomNavigationView
android:id="@+id/navigation"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginEnd="0dp"
android:layout_marginStart="0dp"
app:itemBackground="@color/appcolor"//diffrent color
app:itemIconTint="@color/bnv_tab_item_foreground" //inside folder 2 diff colors
app:itemTextColor="@color/bnv_tab_item_foreground"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:menu="@menu/navigation" />
bnv_tab_item_foreground:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_checked="true" android:color="@color/white" />
<item android:color="@android:color/darker_gray" />
</selector>
Figure 1: File Structure:
ValueError: math domain error
You are trying to do a logarithm of something that is not positive.
Logarithms figure out the base after being given a number and the power it was raised to. log(0)
means that something raised to the power of 2
is 0
. An exponent can never result in 0
*, which means that log(0)
has no answer, thus throwing the math domain error
*Note: 0^0
can result in 0
, but can also result in 1
at the same time. This problem is heavily argued over.
What is a good pattern for using a Global Mutex in C#?
Neither Mutex nor WinApi CreateMutex() works for me.
An alternate solution:
static class Program
{
[STAThread]
static void Main()
{
if (SingleApplicationDetector.IsRunning()) {
return;
}
Application.Run(new MainForm());
SingleApplicationDetector.Close();
}
}
And the SingleApplicationDetector
:
using System;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Security.AccessControl;
using System.Threading;
public static class SingleApplicationDetector
{
public static bool IsRunning()
{
string guid = ((GuidAttribute)Assembly.GetExecutingAssembly().GetCustomAttributes(typeof(GuidAttribute), false).GetValue(0)).Value.ToString();
var semaphoreName = @"Global\" + guid;
try {
__semaphore = Semaphore.OpenExisting(semaphoreName, SemaphoreRights.Synchronize);
Close();
return true;
}
catch (Exception ex) {
__semaphore = new Semaphore(0, 1, semaphoreName);
return false;
}
}
public static void Close()
{
if (__semaphore != null) {
__semaphore.Close();
__semaphore = null;
}
}
private static Semaphore __semaphore;
}
Reason to use Semaphore instead of Mutex:
The Mutex class enforces thread identity, so a mutex can be released only by the thread that acquired it. By contrast, the Semaphore class does not enforce thread identity.
<< System.Threading.Mutex
Ref: Semaphore.OpenExisting()
Calling a javascript function in another js file
My idea is let two JavaScript call function through DOM.
The way to do it is simple ...
We just need to define hidden js_ipc html tag.
After the callee register click from the hidden js_ipc tag, then
The caller can dispatch the click event to trigger callee.
And the argument is save in the event that you want to pass.
When we need to use above way ?
Sometime, the two javascript code is very complicated to integrate and so many async code there. And different code use different framework but you still need to have a simple way to integrate them together.
So, in that case, it is not easy to do it.
In my project's implementation, I meet this case and it is very complicated to integrate. And finally I found out that we can let two javascript call each other through DOM.
I demonstrate this way in this git code. you can get it through this way. (Or read it from https://github.com/milochen0418/javascript-ipc-demo)
git clone https://github.com/milochen0418/javascript-ipc-demo
cd javascript-ipc-demo
git checkout 5f75d44530b4145ca2b06105c6aac28b764f066e
Anywhere, Here, I try to explain by the following simple case. I hope that this way can help you to integrate two different javascript code easier than before there is no any JavaScript library to support communication between two javascript file that made by different team.
<html>
<head>
<link rel="stylesheet" type="text/css" href="css/style.css" />
</head>
<body>
<div id="js_ipc" style="display:none;"></div>
<div id="test_btn" class="btn">
<a><p>click to test</p></a>
</div>
</body>
<script src="js/callee.js"></script>
<script src="js/caller.js"></script>
</html>
And the code
css/style.css
.btn {
background-color:grey;
cursor:pointer;
display:inline-block;
}
js/caller.js
function caller_add_of_ipc(num1, num2) {
var e = new Event("click");
e.arguments = arguments;
document.getElementById("js_ipc").dispatchEvent(e);
}
document.getElementById("test_btn").addEventListener('click', function(e) {
console.log("click to invoke caller of IPC");
caller_add_of_ipc(33, 22);
});
js/callee.js
document.getElementById("js_ipc").addEventListener('click', (e)=>{
callee_add_of_ipc(e.arguments);
});
function callee_add_of_ipc(arguments) {
let num1 = arguments[0];
let num2 = arguments[1];
console.log("This is callee of IPC -- inner-communication process");
console.log( "num1 + num2 = " + (num1 + num2));
}
How to access the elements of a 2D array?
Seems to work here:
>>> a=[[1,1],[2,1],[3,1]]
>>> a
[[1, 1], [2, 1], [3, 1]]
>>> a[1]
[2, 1]
>>> a[1][0]
2
>>> a[1][1]
1
jar not loaded. See Servlet Spec 2.3, section 9.7.2. Offending class: javax/servlet/Servlet.class
Exclusions and provided
dependencies will not work in child projects.
If you are using inheritance in Maven projects you must include this configuration on the parent pom.xml
file. You will have a <parent>...</parent>
section in your pom.xml if you are using inheritance. So you will have something like this in your parent pom.xml
:
<groupId>some.groupId</groupId>
<version>1.0</version>
<artifactId>someArtifactId</artifactId>
<packaging>pom</packaging>
<modules>
<module>child-module-1</module>
<module>child-module-2</module>
</modules>
<dependencies>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.1</version>
<scope>provided</scope>
</dependency>
</dependencies>
HTML5 Canvas vs. SVG vs. div
To add to this, I've been doing a diagram application, and initially started out with canvas. The diagram consists of many nodes, and they can get quite big. The user can drag elements in the diagram around.
What I found was that on my Mac, for very large images, SVG is superior. I have a MacBook Pro 2013 13" Retina, and it runs the fiddle below quite well. The image is 6000x6000 pixels, and has 1000 objects. A similar construction in canvas was impossible to animate for me when the user was dragging objects around in the diagram.
On modern displays you also have to account for different resolutions, and here SVG gives you all of this for free.
Fiddle: http://jsfiddle.net/knutsi/PUcr8/16/
Fullscreen: http://jsfiddle.net/knutsi/PUcr8/16/embedded/result/
var wiggle_factor = 0.0;
nodes = [];
// create svg:
var svg = document.createElementNS("http://www.w3.org/2000/svg", "svg");
svg.setAttribute('style', 'border: 1px solid black');
svg.setAttribute('width', '6000');
svg.setAttribute('height', '6000');
svg.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns:xlink",
"http://www.w3.org/1999/xlink");
document.body.appendChild(svg);
function makeNode(wiggle) {
var node = document.createElementNS("http://www.w3.org/2000/svg", "g");
var node_x = (Math.random() * 6000);
var node_y = (Math.random() * 6000);
node.setAttribute("transform", "translate(" + node_x + ", " + node_y +")");
// circle:
var circ = document.createElementNS("http://www.w3.org/2000/svg", "circle");
circ.setAttribute( "id","cir")
circ.setAttribute( "cx", 0 + "px")
circ.setAttribute( "cy", 0 + "px")
circ.setAttribute( "r","100px");
circ.setAttribute('fill', 'red');
circ.setAttribute('pointer-events', 'inherit')
// text:
var text = document.createElementNS("http://www.w3.org/2000/svg", "text");
text.textContent = "This is a test! ÅÆØ";
node.appendChild(circ);
node.appendChild(text);
node.x = node_x;
node.y = node_y;
if(wiggle)
nodes.push(node)
return node;
}
// populate with 1000 nodes:
for(var i = 0; i < 1000; i++) {
var node = makeNode(true);
svg.appendChild(node);
}
// make one mapped to mouse:
var bnode = makeNode(false);
svg.appendChild(bnode);
document.body.onmousemove=function(event){
bnode.setAttribute("transform","translate(" +
(event.clientX + window.pageXOffset) + ", " +
(event.clientY + window.pageYOffset) +")");
};
setInterval(function() {
wiggle_factor += 1/60;
nodes.forEach(function(node) {
node.setAttribute("transform", "translate("
+ (Math.sin(wiggle_factor) * 200 + node.x)
+ ", "
+ (Math.sin(wiggle_factor) * 200 + node.y)
+ ")");
})
},1000/60);
R apply function with multiple parameters
If your function have two vector variables and must compute itself on each value of them (as mentioned by @Ari B. Friedman) you can use mapply
as follows:
vars1<-c(1,2,3)
vars2<-c(10,20,30)
mult_one<-function(var1,var2)
{
var1*var2
}
mapply(mult_one,vars1,vars2)
which gives you:
> mapply(mult_one,vars1,vars2)
[1] 10 40 90
What is the simplest way to SSH using Python?
Your definition of "simplest" is important here - simple code means using a module (though "large external library" is an exaggeration).
I believe the most up-to-date (actively developed) module is paramiko. It comes with demo scripts in the download, and has detailed online API documentation. You could also try PxSSH, which is contained in pexpect. There's a short sample along with the documentation at the first link.
Again with respect to simplicity, note that good error-detection is always going to make your code look more complex, but you should be able to reuse a lot of code from the sample scripts then forget about it.
Batch files : How to leave the console window open
If that is really all the batch file is doing, remove the cmd /K
and add PAUSE
.
start /B /LOW /WAIT make package
PAUSE
Then, just point your shortcut to "My Batch File.bat"
...no need to run it with CMD /K
.
UPDATE
Ah, some new info...you're trying to do it from a pinned shortcut on the taskbar.
I found this, Adding Batch Files to Windows 7 Taskbar like the Vista/XP Quick Launch, with the relevant part below.
- First, pin a shortcut for
CMD.EXE
to the taskbar by hitting the start button, then type "cmd" in the search box, right-click the result and chose "Pin to Taskbar".
- Right-click the shortcut on the taskbar.
- You will see a list that includes "Command Prompt" and "Unpin this program from the taskbar".
- Right-click the icon for
CMD.EXE
and select Properties
.
- In the box for Target, go to the end of
"%SystemRoot%\system32\cmd.exe"
and type " /C "
and the path and name
of the batch file.
For your purposes, you can either:
Use /C
and put a PAUSE
at the end of your batch file.
OR
- Change the command line to use
/K
and remove the PAUSE
from your batch file.
How to secure an ASP.NET Web API
Update:
I have added this link to my other answer how to use JWT authentication for ASP.NET Web API here for anyone interested in JWT.
We have managed to apply HMAC authentication to secure Web API, and it worked okay. HMAC authentication uses a secret key for each consumer which both consumer and server both know to hmac hash a message, HMAC256 should be used. Most of the cases, hashed password of the consumer is used as a secret key.
The message normally is built from data in the HTTP request, or even customized data which is added to HTTP header, the message might include:
- Timestamp: time that request is sent (UTC or GMT)
- HTTP verb: GET, POST, PUT, DELETE.
- post data and query string,
- URL
Under the hood, HMAC authentication would be:
Consumer sends a HTTP request to web server, after building the signature (output of hmac hash), the template of HTTP request:
User-Agent: {agent}
Host: {host}
Timestamp: {timestamp}
Authentication: {username}:{signature}
Example for GET request:
GET /webapi.hmac/api/values
User-Agent: Fiddler
Host: localhost
Timestamp: Thursday, August 02, 2012 3:30:32 PM
Authentication: cuongle:LohrhqqoDy6PhLrHAXi7dUVACyJZilQtlDzNbLqzXlw=
The message to hash to get signature:
GET\n
Thursday, August 02, 2012 3:30:32 PM\n
/webapi.hmac/api/values\n
Example for POST request with query string (signature below is not correct, just an example)
POST /webapi.hmac/api/values?key2=value2
User-Agent: Fiddler
Host: localhost
Content-Type: application/x-www-form-urlencoded
Timestamp: Thursday, August 02, 2012 3:30:32 PM
Authentication: cuongle:LohrhqqoDy6PhLrHAXi7dUVACyJZilQtlDzNbLqzXlw=
key1=value1&key3=value3
The message to hash to get signature
GET\n
Thursday, August 02, 2012 3:30:32 PM\n
/webapi.hmac/api/values\n
key1=value1&key2=value2&key3=value3
Please note that form data and query string should be in order, so the code on the server get query string and form data to build the correct message.
When HTTP request comes to the server, an authentication action filter is implemented to parse the request to get information: HTTP verb, timestamp, uri, form data and query string, then based on these to build signature (use hmac hash) with the secret key (hashed password) on the server.
The secret key is got from the database with the username on the request.
Then server code compares the signature on the request with the signature built; if equal, authentication is passed, otherwise, it failed.
The code to build signature:
private static string ComputeHash(string hashedPassword, string message)
{
var key = Encoding.UTF8.GetBytes(hashedPassword.ToUpper());
string hashString;
using (var hmac = new HMACSHA256(key))
{
var hash = hmac.ComputeHash(Encoding.UTF8.GetBytes(message));
hashString = Convert.ToBase64String(hash);
}
return hashString;
}
So, how to prevent replay attack?
Add constraint for the timestamp, something like:
servertime - X minutes|seconds <= timestamp <= servertime + X minutes|seconds
(servertime: time of request coming to server)
And, cache the signature of the request in memory (use MemoryCache, should keep in the limit of time). If the next request comes with the same signature with the previous request, it will be rejected.
The demo code is put as here:
https://github.com/cuongle/Hmac.WebApi
load csv into 2D matrix with numpy for plotting
You can read a CSV file with headers into a NumPy structured array with np.genfromtxt. For example:
import numpy as np
csv_fname = 'file.csv'
with open(csv_fname, 'w') as fp:
fp.write("""\
"A","B","C","D","E","F","timestamp"
611.88243,9089.5601,5133.0,864.07514,1715.37476,765.22777,1.291111964948E12
611.88243,9089.5601,5133.0,864.07514,1715.37476,765.22777,1.291113113366E12
611.88243,9089.5601,5133.0,864.07514,1715.37476,765.22777,1.291120650486E12
""")
# Read the CSV file into a Numpy record array
r = np.genfromtxt(csv_fname, delimiter=',', names=True, case_sensitive=True)
print(repr(r))
which looks like this:
array([(611.88243, 9089.5601, 5133., 864.07514, 1715.37476, 765.22777, 1.29111196e+12),
(611.88243, 9089.5601, 5133., 864.07514, 1715.37476, 765.22777, 1.29111311e+12),
(611.88243, 9089.5601, 5133., 864.07514, 1715.37476, 765.22777, 1.29112065e+12)],
dtype=[('A', '<f8'), ('B', '<f8'), ('C', '<f8'), ('D', '<f8'), ('E', '<f8'), ('F', '<f8'), ('timestamp', '<f8')])
You can access a named column like this r['E']
:
array([1715.37476, 1715.37476, 1715.37476])
Note: this answer previously used np.recfromcsv to read the data into a NumPy record array. While there was nothing wrong with that method, structured arrays are generally better than record arrays for speed and compatibility.
Using regular expression in css?
Try my generic CSS regular expression
(([a-z]{5,6}.*?\))|([\d.+-]?)(?![a-z\s#.()%])(\d?\.?\d?)?[a-z\d%]+)|(url\([/"'][a-z:/.]*['")]\))|(rgb|hsl)a?\(\d+%?,?\s?\d+%?,?\s?\d+%?(,\s?\d+\.?\d?)?\)|(#(\w|[\d]){3,8})|([\w]{3,8}(?=.*-))
Demo https://regexr.com/4a22i
LINQ extension methods - Any() vs. Where() vs. Exists()
foreach (var item in model.Where(x => !model2.Any(y => y.ID == x.ID)).ToList())
{
enter code here
}
same work you also can do with Contains
secondly Where
is give you new list of values.
thirdly using Exist
is not a good practice, you can achieve your target from Any
and contains
like
EmployeeDetail _E = Db.EmployeeDetails.where(x=>x.Id==1).FirstOrDefault();
Hope this will clear your confusion.
Pip freeze vs. pip list
pip list
List installed packages: show ALL installed packages that even pip installed implictly
pip freeze
List installed packages: - list of packages that are installed using pip command
pip freeze has --all
flag to show all the packages.
Other difference is the output it renders, that you can check by running the commands.
How to run the sftp command with a password from Bash script?
I was recently asked to switch over from ftp to sftp, in order to secure the file transmission between servers. We are using Tectia SSH package, which has an option --password
to pass the password on the command line.
example : sftp --password="password" "userid"@"servername"
Batch example :
(
echo "
ascii
cd pub
lcd dir_name
put filename
close
quit
"
) | sftp --password="password" "userid"@"servername"
I thought I should share this information, since I was looking at various websites, before running the help command (sftp -h
), and was i surprised to see the password option.
Bat file to run a .exe at the command prompt
it is very simple code for executing notepad
bellow code type into a notepad and save to extension .bat Exapmle:notepad.bat
start "c:\windows\system32" notepad.exe
(above code "c:\windows\system32" is path where you kept your .exe program and notepad.exe is your .exe program file file)
enjoy!
do <something> N times (declarative syntax)
function doSomthing() {
...
}
Use it like so:
Array.from(Array(length).keys()).forEach(doSomthing);
Or
Array.from({ length }, (v, i) => i).forEach(doSomthing);
Or
// array start counting from 1
Array.from({ length }, (v, i) => ++i).forEach(doSomthing);
Loop through Map in Groovy?
When using the for loop, the value of s is a Map.Entry element, meaning that you can get the key from s.key and the value from s.value
Android ImageView Animation
You can also simply use the Rotate animation feature. That runs a specific animation, for a pre-determined amount of time, on an ImageView.
Animation rotate = AnimationUtils.loadAnimation([context], R.anim.rotate_picture);
splash.startAnimation(rotate);
Then create an animation XML file in your res/anim called rotate_picture with the content:
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
android:shareInterpolator="false">
<rotate
android:fromDegrees="0"
android:toDegrees="360"
android:duration="5000"
android:pivotX="50%"
android:pivotY="50%">
</rotate>
</set>
Now unfortunately, this will only run it once. You'll need a loop somewhere to make it repeat the animation while it's waiting. I experimented a little bit and got my program stuck in infinite loops, so I'm not sure of the best way to that. EDIT: Christopher's answer provides the info on how to make it loop properly, so removing my bad suggestion about separate threads!
How to join multiple collections with $lookup in mongodb
According to the documentation, $lookup can join only one external collection.
What you could do is to combine userInfo
and userRole
in one collection, as provided example is based on relational DB schema. Mongo is noSQL database - and this require different approach for document management.
Please find below 2-step query, which combines userInfo with userRole - creating new temporary collection used in last query to display combined data.
In last query there is an option to use $out and create new collection with merged data for later use.
create collections
db.sivaUser.insert(
{
"_id" : ObjectId("5684f3c454b1fd6926c324fd"),
"email" : "[email protected]",
"userId" : "AD",
"userName" : "admin"
})
//"userinfo"
db.sivaUserInfo.insert(
{
"_id" : ObjectId("56d82612b63f1c31cf906003"),
"userId" : "AD",
"phone" : "0000000000"
})
//"userrole"
db.sivaUserRole.insert(
{
"_id" : ObjectId("56d82612b63f1c31cf906003"),
"userId" : "AD",
"role" : "admin"
})
"join" them all :-)
db.sivaUserInfo.aggregate([
{$lookup:
{
from: "sivaUserRole",
localField: "userId",
foreignField: "userId",
as: "userRole"
}
},
{
$unwind:"$userRole"
},
{
$project:{
"_id":1,
"userId" : 1,
"phone" : 1,
"role" :"$userRole.role"
}
},
{
$out:"sivaUserTmp"
}
])
db.sivaUserTmp.aggregate([
{$lookup:
{
from: "sivaUser",
localField: "userId",
foreignField: "userId",
as: "user"
}
},
{
$unwind:"$user"
},
{
$project:{
"_id":1,
"userId" : 1,
"phone" : 1,
"role" :1,
"email" : "$user.email",
"userName" : "$user.userName"
}
}
])
Change select box option background color
Yes, you can set this by the opposite way:
select { /* desired background */ }
option:not(:checked) { background: #fff; }
Check it working bellow:
_x000D_
_x000D_
select {
margin: 50px;
width: 300px;
background: #ff0;
color: #000;
}
option:not(:checked) {
background-color: #fff;
}
_x000D_
<select>
<option val="">Select Option</option>
<option val="1">Option 1</option>
<option val="2">Option 2</option>
<option val="3">Option 3</option>
<option val="4">Option 4</option>
</select>
_x000D_
_x000D_
_x000D_
Push git commits & tags simultaneously
Maybe this helps someone:
git tag 0.0.1 # creates tag locally
git push origin 0.0.1 # pushes tag to remote
git tag --delete 0.0.1 # deletes tag locally
git push --delete origin 0.0.1 # deletes remote tag
How to find the Git commit that introduced a string in any branch?
Messing around with the same answers:
$ git config --global alias.find '!git log --color -p -S '
- ! is needed because other way, git do not pass argument correctly to -S. See this response
- --color and -p helps to show exactly "whatchanged"
Now you can do
$ git find <whatever>
or
$ git find <whatever> --all
$ git find <whatever> master develop
Using Address Instead Of Longitude And Latitude With Google Maps API
var geocoder;
var map;
function initialize() {
geocoder = new google.maps.Geocoder();
var latlng = new google.maps.LatLng(-34.397, 150.644);
var mapOptions = {
zoom: 8,
center: latlng
}
map = new google.maps.Map(document.getElementById('map'), mapOptions);
}
function codeAddress() {
var address = document.getElementById('address').value;
geocoder.geocode( { 'address': address}, function(results, status) {
if (status == 'OK') {
map.setCenter(results[0].geometry.location);
var marker = new google.maps.Marker({
map: map,
position: results[0].geometry.location
});
} else {
alert('Geocode was not successful for the following reason: ' + status);
}
});
}
<body onload="initialize()">
<div id="map" style="width: 320px; height: 480px;"></div>
<div>
<input id="address" type="textbox" value="Sydney, NSW">
<input type="button" value="Encode" onclick="codeAddress()">
</div>
</body>
Or refer to the documentation https://developers.google.com/maps/documentation/javascript/geocoding
How to rename a directory/folder on GitHub website?
As a newer user to git, I took the following approach. From the command line, I was able to rename a folder by creating a new folder, copying the files to it, adding and commiting locally and pushing. These are my steps:
$mkdir newfolder
$cp oldfolder/* newfolder
$git add newfolder
$git commit -m 'start rename'
$git push #New Folder appears on Github
$git rm -r oldfolder
$git commit -m 'rename complete'
$git push #Old Folder disappears on Github
Probably a better way, but it worked for me.
How do I declare an array with a custom class?
Your class:
class name {
public:
string first;
string last;
name() { } //Default constructor.
name(string a, string b){
first = a;
last = b;
}
};
Has an explicit constructor that requires two string parameters. Classes with no constructor written explicitly get default constructors taking no parameters. Adding the explicit one stopped the compiler from generating that default constructor for you.
So, if you wish to make an array of uninitialized objects, add a default constructor to your class so the compiler knows how to create them without providing those two string parameters - see the commented line above.
Detecting user leaving page with react-router
For react-router
2.4.0+
NOTE: It is advisable to migrate all your code to the latest react-router
to get all the new goodies.
As recommended in the react-router documentation:
One should use the withRouter
higher order component:
We think this new HoC is nicer and easier, and will be using it in
documentation and examples, but it is not a hard requirement to
switch.
As an ES6 example from the documentation:
import React from 'react'
import { withRouter } from 'react-router'
const Page = React.createClass({
componentDidMount() {
this.props.router.setRouteLeaveHook(this.props.route, () => {
if (this.state.unsaved)
return 'You have unsaved information, are you sure you want to leave this page?'
})
}
render() {
return <div>Stuff</div>
}
})
export default withRouter(Page)
Sum columns with null values in oracle
The other answers regarding the use of nvl() are correct however none seem to address a more salient point:
Should you even have NULLs in this column?
Do they have a meaning other than 0?
This seems like a case where you should have a NOT NULL DEFAULT 0 on th ecolumn
Excel - Shading entire row based on change of value
I have found a simple solution to banding by content at Pearson Software Consulting:
Let's say the header is from A1 to B1, table data is from A2 to B5, the controling cell is in the A column
- Make a new column, C
- At first the first row to color make the formula =true in the C2 cell
- In the second row make the formula =IF(A3=A2,C2,NOT(C2))
- Fill the column down to the last row
- Select the data range
- Select conditional formatting, choose Use a formula... and put =$C2 as the formula
"Auth Failed" error with EGit and GitHub
For you who, like me, already did setup you ssh-keys but still get the errors:
Make sure you did setup a push remote. It worked for me when I got both the Cannot get remote repository refs-problems ("... Passphrase for..." and "Auth fail" in the "Push..." dialog).
Provided that you already:
Setup your SSH keys with Github (Window > Preferences > General > Network Connections > SSH2)
Setup your local repository (you can follow this guide for that)
Created a Github repository (same guide)
... here's how you do it:
- Go to the Git Repositories view (Window > Show View > Other > Git Repositories)
- Expand your Repository and right click Remotes --> "Create Remote"
- "Remote Name": origin, "Configure push": checked --> click "OK"
- Click the "Change..." button
- Paste your git URI and select protocol ssh --> click "Finish"
- Now, click "Save and Push" and NOW you should get a password prompt --> enter the public key passphrase here (provided that you DID (and you should) setup a passphrase to your public key) --> click "OK"
- Now you should get a confirmation window saying "Pushed to YourRepository - origin" --> click "OK"
- Push to upstream, but this time use "Configured remote repository" as your Destination Git repository
- Go get yourself a well earned cup of coffee!
How do I add a .click() event to an image?
First of all, this line
<img src="http://soulsnatcher.bplaced.net/LDRYh.jpg" alt="unfinished bingo card" />.click()
You're mixing HTML and JavaScript. It doesn't work like that. Get rid of the .click()
there.
If you read the JavaScript you've got there, document.getElementById('foo')
it's looking for an HTML element with an ID of foo
. You don't have one. Give your image that ID:
<img id="foo" src="http://soulsnatcher.bplaced.net/LDRYh.jpg" alt="unfinished bingo card" />
Alternatively, you could throw the JS in a function and put an onclick in your HTML:
<img src="http://soulsnatcher.bplaced.net/LDRYh.jpg" alt="unfinished bingo card" onclick="myfunction()" />
I suggest you do some reading up on JavaScript and HTML though.
The others are right about needing to move the <img>
above the JS click binding too.
How to replace text of a cell based on condition in excel
You can use the Conditional Formatting to replace text and NOT effect any formulas. Simply go to the Rule's format where you will see Number, Font, Border and Fill.
Go to the Number tab and select CUSTOM
. Then simply type where it says TYPE
: what you want to say in QUOTES.
Example.. "OTHER"
Programmatically register a broadcast receiver
for LocalBroadcastManager
Intent intent = new Intent("any.action.string");
LocalBroadcastManager.getInstance(context).
sendBroadcast(intent);
and register in onResume
LocalBroadcastManager.getInstance(
ActivityName.this).registerReceiver(chatCountBroadcastReceiver, filter);
and Unregister it onStop
LocalBroadcastManager.getInstance(
ActivityName.this).unregisterReceiver(chatCountBroadcastReceiver);
and recieve it ..
mBroadcastReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
Log.e("mBroadcastReceiver", "onReceive");
}
};
where IntentFilter is
new IntentFilter("any.action.string")
How does HTTP_USER_AGENT work?
The user agent string is a text that the browsers themselves send to the webserver to identify themselves, so that websites can send different content based on the browser or based on browser compatibility.
Mozilla is a browser rendering engine (the one at the core of Firefox) and the fact that Chrome and IE contain the string Mozilla/4 or /5 identifies them as being compatible with that rendering engine.
Element-wise addition of 2 lists?
I haven't timed it but I suspect this would be pretty quick:
import numpy as np
list1=[1, 2, 3]
list2=[4, 5, 6]
list_sum = (np.add(list1, list2)).tolist()
[5, 7, 9]
Create a new file in git bash
If you are using the Git Bash shell, you can use the following trick:
> webpage.html
This is actually the same as:
echo "" > webpage.html
Then, you can use git add webpage.html
to stage the file.
Send mail via CMD console
Scenario:
Your domain: mydomain.com
Domain you wish to send to: theirdomain.com
1. Determine the mail server you're sending to.
Open a CMD prompt
Type
NSLOOKUP
set q=mx
theirdomain.com
Response:
Non-authoritative answer:
theirdomain.com MX preference = 50, mail exchanger = mail.theirdomain.com
Nslookup_big
EDIT
Be sure to type exit to terminate NSLOOKUP.
2. Connect to their mail server
SMTP communicates over port 25. We will now try to use TELNET to connect to their mail server "mail.theirdomain.com"
Open a CMD prompt
TELNET MAIL.THEIRDOMAIN.COM 25
You should see something like this as a response:
220 mx.google.com ESMTP 6si6253627yxg.6
Be aware that different servers will come up with different greetings but you should get SOMETHING. If nothing comes up at this point there are 2 possible problems. Port 25 is being blocked at your firewall, or their server is not responding. Try a different domain, if that works then it's not you.
3. Send an Email
Now, use simple SMTP commands to send a test email. This is very important, you CANNOT use the backspace key, it will work onscreen but not be interpreted correctly. You have to type these commands perfectly.
ehlo mydomain.com
mail from:<[email protected]>
rcpt to:<[email protected]>
data
This is a test, please do not respond
.
quit
So, what does that all mean?
EHLO - introduce yourself to the mail server HELO can also be used but EHLO tells the server to use the extended command set (not that we're using that).
MAIL FROM - who's sending the email. Make sure to place this is the greater than/less than brackets as many email servers will require this (Postini).
RCPT TO - who you're sending it to. Again you need to use the brackets. See Step #4 on how to test relaying mail!
DATA - tells the SMTP server that what follows is the body of your email. Make sure to hit "Enter" at the end.
. - the period alone on the line tells the SMTP server you're all done with the data portion and it's clear to send the email.
quit - exits the TELNET session.
4. Test SMTP relay
Testing SMTP relay is very easy, and simply requires a small change to the above commands. See below:
ehlo mydomain.com
mail from:<[email protected]>
rcpt to:<[email protected]>
data
This is a test, please do not respond
.
quit
See the difference? On the RCPT TO line, we're sending to a domain that is not controlled by the SMTP server we're sending to. You will get an immediate error is SMTP relay is turned off. If you're able to continue and send an email, then relay is allowed by that server.
fill an array in C#
int[] arr = Enumerable.Repeat(42, 10000).ToArray();
I believe that this does the job :)
How can I loop through all rows of a table? (MySQL)
Mr Purple's example I used in mysql trigger like that,
begin
DECLARE n INT DEFAULT 0;
DECLARE i INT DEFAULT 0;
Select COUNT(*) from user where deleted_at is null INTO n;
SET i=0;
WHILE i<n DO
INSERT INTO user_notification(notification_id,status,userId)values(new.notification_id,1,(Select userId FROM user LIMIT i,1)) ;
SET i = i + 1;
END WHILE;
end
urllib2.HTTPError: HTTP Error 403: Forbidden
NSE website has changed and the older scripts are semi-optimum to current website. This snippet can gather daily details of security. Details include symbol, security type, previous close, open price, high price, low price, average price, traded quantity, turnover, number of trades, deliverable quantities and ratio of delivered vs traded in percentage. These conveniently presented as list of dictionary form.
Python 3.X version with requests and BeautifulSoup
from requests import get
from csv import DictReader
from bs4 import BeautifulSoup as Soup
from datetime import date
from io import StringIO
SECURITY_NAME="3MINDIA" # Change this to get quote for another stock
START_DATE= date(2017, 1, 1) # Start date of stock quote data DD-MM-YYYY
END_DATE= date(2017, 9, 14) # End date of stock quote data DD-MM-YYYY
BASE_URL = "https://www.nseindia.com/products/dynaContent/common/productsSymbolMapping.jsp?symbol={security}&segmentLink=3&symbolCount=1&series=ALL&dateRange=+&fromDate={start_date}&toDate={end_date}&dataType=PRICEVOLUMEDELIVERABLE"
def getquote(symbol, start, end):
start = start.strftime("%-d-%-m-%Y")
end = end.strftime("%-d-%-m-%Y")
hdr = {'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11',
'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
'Referer': 'https://cssspritegenerator.com',
'Accept-Charset': 'ISO-8859-1,utf-8;q=0.7,*;q=0.3',
'Accept-Encoding': 'none',
'Accept-Language': 'en-US,en;q=0.8',
'Connection': 'keep-alive'}
url = BASE_URL.format(security=symbol, start_date=start, end_date=end)
d = get(url, headers=hdr)
soup = Soup(d.content, 'html.parser')
payload = soup.find('div', {'id': 'csvContentDiv'}).text.replace(':', '\n')
csv = DictReader(StringIO(payload))
for row in csv:
print({k:v.strip() for k, v in row.items()})
if __name__ == '__main__':
getquote(SECURITY_NAME, START_DATE, END_DATE)
Besides this is relatively modular and ready to use snippet.
Pointers in C: when to use the ampersand and the asterisk?
Put simply
&
means the address-of, you will see that in placeholders for functions to modify the parameter variable as in C, parameter variables are passed by value, using the ampersand means to pass by reference.
*
means the dereference of a pointer variable, meaning to get the value of that pointer variable.
int foo(int *x){
*x++;
}
int main(int argc, char **argv){
int y = 5;
foo(&y); // Now y is incremented and in scope here
printf("value of y = %d\n", y); // output is 6
/* ... */
}
The above example illustrates how to call a function foo
by using pass-by-reference, compare with this
int foo(int x){
x++;
}
int main(int argc, char **argv){
int y = 5;
foo(y); // Now y is still 5
printf("value of y = %d\n", y); // output is 5
/* ... */
}
Here's an illustration of using a dereference
int main(int argc, char **argv){
int y = 5;
int *p = NULL;
p = &y;
printf("value of *p = %d\n", *p); // output is 5
}
The above illustrates how we got the address-of y
and assigned it to the pointer variable p
. Then we dereference p
by attaching the *
to the front of it to obtain the value of p
, i.e. *p
.
What's the foolproof way to tell which version(s) of .NET are installed on a production Windows Server?
To determine your server's support for .NET Framework 4.5 and later versions (tested through 4.5.2): If you don't have Registry access on the server, but have app publish rights to that server, create an MVC 5 app with a trivial controller, like this:
using System.Web.Mvc;
namespace DotnetVersionTest.Controllers
{
public class DefaultController : Controller
{
public string Index()
{
return "simple .NET version test...";
}
}
}
Then in your Web.config, walk through the desired .NET Framework versions in the following section, changing the targetFramework
values as desired:
<system.web>
<customErrors mode="Off"/>
<compilation debug="true" targetFramework="4.5.2"/>
<httpRuntime targetFramework="4.5.2"/>
</system.web>
Publish each target to your server, then browse to <app deploy URL>/Default
. If your server supports the target framework, then the simple string will display from your trivial Controller. If not, you'll receive an error like the following:
So in this case, my target server doesn't yet support .NET Framework 4.5.2.
Haskell: Converting Int to String
Anyone who is just starting with Haskell and trying to print an Int, use:
module Lib
( someFunc
) where
someFunc :: IO ()
x = 123
someFunc = putStrLn (show x)
Getting the client IP address: REMOTE_ADDR, HTTP_X_FORWARDED_FOR, what else could be useful?
If you're behind a proxy, you should use X-Forwarded-For
: http://en.wikipedia.org/wiki/X-Forwarded-For
It is an IETF draft standard with wide support:
The X-Forwarded-For field is supported by most proxy servers,
including Squid, Apache mod_proxy, Pound, HAProxy, Varnish cache,
IronPort Web Security Appliance, AVANU WebMux, ArrayNetworks,
Radware's AppDirector and Alteon ADC, ADC-VX, and ADC-VA, F5 Big-IP,
Blue Coat ProxySG, Cisco Cache Engine, McAfee Web Gateway, Phion
Airlock, Finjan's Vital Security, NetApp NetCache, jetNEXUS, Crescendo
Networks' Maestro, Web Adjuster and Websense Web Security Gateway.
If not, here are a couple other common headers I've seen:
Classes vs. Modules in VB.NET
It is acceptable to use Module
. Module
is not used as a replacement for Class
. Module
serves its own purpose. The purpose of Module
is to use as a container for
- extension methods,
- variables that are not specific to any
Class
, or
- variables that do not fit properly in any
Class
.
Module
is not like a Class
since you cannot
- inherit from a
Module
,
- implement an
Interface
with a Module
,
- nor create an instance of a
Module
.
Anything inside a Module
can be directly accessed within the Module
assembly without referring to the Module
by its name. By default, the access level for a Module
is Friend
.
How to determine equality for two JavaScript objects?
- sort the objects (dictionary)
compare JSON string
function areTwoDictsEqual(dictA, dictB) {
function sortDict(dict) {
var keys = Object.keys(dict);
keys.sort();
var newDict = {};
for (var i=0; i<keys.length; i++) {
var key = keys[i];
var value = dict[key];
newDict[key] = value;
}
return newDict;
}
return JSON.stringify(sortDict(dictA)) == JSON.stringify(sortDict(dictB));
}
pandas create new column based on values from other columns / apply a function of multiple columns, row-wise
The answers above are perfectly valid, but a vectorized solution exists, in the form of numpy.select
. This allows you to define conditions, then define outputs for those conditions, much more efficiently than using apply
:
First, define conditions:
conditions = [
df['eri_hispanic'] == 1,
df[['eri_afr_amer', 'eri_asian', 'eri_hawaiian', 'eri_nat_amer', 'eri_white']].sum(1).gt(1),
df['eri_nat_amer'] == 1,
df['eri_asian'] == 1,
df['eri_afr_amer'] == 1,
df['eri_hawaiian'] == 1,
df['eri_white'] == 1,
]
Now, define the corresponding outputs:
outputs = [
'Hispanic', 'Two Or More', 'A/I AK Native', 'Asian', 'Black/AA', 'Haw/Pac Isl.', 'White'
]
Finally, using numpy.select
:
res = np.select(conditions, outputs, 'Other')
pd.Series(res)
0 White
1 Hispanic
2 White
3 White
4 Other
5 White
6 Two Or More
7 White
8 Haw/Pac Isl.
9 White
dtype: object
Why should numpy.select
be used over apply
? Here are some performance checks:
df = pd.concat([df]*1000)
In [42]: %timeit df.apply(lambda row: label_race(row), axis=1)
1.07 s ± 4.16 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)
In [44]: %%timeit
...: conditions = [
...: df['eri_hispanic'] == 1,
...: df[['eri_afr_amer', 'eri_asian', 'eri_hawaiian', 'eri_nat_amer', 'eri_white']].sum(1).gt(1),
...: df['eri_nat_amer'] == 1,
...: df['eri_asian'] == 1,
...: df['eri_afr_amer'] == 1,
...: df['eri_hawaiian'] == 1,
...: df['eri_white'] == 1,
...: ]
...:
...: outputs = [
...: 'Hispanic', 'Two Or More', 'A/I AK Native', 'Asian', 'Black/AA', 'Haw/Pac Isl.', 'White'
...: ]
...:
...: np.select(conditions, outputs, 'Other')
...:
...:
3.09 ms ± 17 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
Using numpy.select
gives us vastly improved performance, and the discrepancy will only increase as the data grows.
For Loop on Lua
Your problem is simple:
names = {'John', 'Joe', 'Steve'}
for names = 1, 3 do
print (names)
end
This code first declares a global variable called names
. Then, you start a for loop. The for loop declares a local variable that just happens to be called names
too; the fact that a variable had previously been defined with names
is entirely irrelevant. Any use of names
inside the for loop will refer to the local one, not the global one.
The for loop says that the inner part of the loop will be called with names = 1
, then names = 2
, and finally names = 3
. The for loop declares a counter that counts from the first number to the last, and it will call the inner code once for each value it counts.
What you actually wanted was something like this:
names = {'John', 'Joe', 'Steve'}
for nameCount = 1, 3 do
print (names[nameCount])
end
The [] syntax is how you access the members of a Lua table. Lua tables map "keys" to "values". Your array automatically creates keys of integer type, which increase. So the key associated with "Joe" in the table is 2 (Lua indices always start at 1).
Therefore, you need a for loop that counts from 1 to 3, which you get. You use the count variable to access the element from the table.
However, this has a flaw. What happens if you remove one of the elements from the list?
names = {'John', 'Joe'}
for nameCount = 1, 3 do
print (names[nameCount])
end
Now, we get John Joe nil
, because attempting to access values from a table that don't exist results in nil
. To prevent this, we need to count from 1 to the length of the table:
names = {'John', 'Joe'}
for nameCount = 1, #names do
print (names[nameCount])
end
The #
is the length operator. It works on tables and strings, returning the length of either. Now, no matter how large or small names
gets, this will always work.
However, there is a more convenient way to iterate through an array of items:
names = {'John', 'Joe', 'Steve'}
for i, name in ipairs(names) do
print (name)
end
ipairs
is a Lua standard function that iterates over a list. This style of for
loop, the iterator for loop, uses this kind of iterator function. The i
value is the index of the entry in the array. The name
value is the value at that index. So it basically does a lot of grunt work for you.
is there a function in lodash to replace matched item
Came across this as well and did it simply that way.
const persons = [{id: 1, name: "Person 1"}, {id:2, name:"Person 2"}];
const updatedPerson = {id: 1, name: "new Person Name"}
const updatedPersons = persons.map(person => (
person.id === updated.id
? updatedPerson
: person
))
If wanted we can generalize it
const replaceWhere = (list, predicate, replacement) => {
return list.map(item => predicate(item) ? replacement : item)
}
replaceWhere(persons, person => person.id === updatedPerson.id, updatedPerson)
How to get names of enum entries?
Another interesting solution found here is using ES6 Map:
export enum Type {
low,
mid,
high
}
export const TypeLabel = new Map<number, string>([
[Type.low, 'Low Season'],
[Type.mid, 'Mid Season'],
[Type.high, 'High Season']
]);
USE
console.log(TypeLabel.get(Type.low)); // Low Season
Initializing array of structures
This is quite simple:
my_data
is a before defined structure type.
So you want to declare an my_data
-array of some elements, as you would do with
char a[] = { 'a', 'b', 'c', 'd' };
So the array would have 4 elements and you initialise them as
a[0] = 'a', a[1] = 'b', a[1] = 'c', a[1] ='d';
This is called a designated initializer (as i remember right).
and it just indicates that data has to be of type my_dat
and has to be an array that needs to store so many my_data structures that there is a structure with each type member name Peter, James, John and Mike.
how to drop database in sqlite?
You can drop tables
by issuing an SQL Command as you would normally. If you want to drop the whole database you'll have to delete the file. You can delete the file located under
data/data/com.your.app.name/database/[databasefilename]
you can do this from the eclipse view called "FileBrowser" out of the "Android" Category for example. Or directly on your emulator or phone.
The difference between the Runnable and Callable interfaces in Java
As it was already mentioned here Callable is relatively new interface and it was introduced as a part of concurrency package. Both Callable and Runnable can be used with executors. Class Thread (that implements Runnable itself) supports Runnable only.
You can still use Runnable with executors. The advantage of Callable that you can send it to executor and immediately get back Future result that will be updated when the execution is finished. The same may be implemented with Runnable, but in this case you have to manage the results yourself. For example you can create results queue that will hold all results. Other thread can wait on this queue and deal with results that arrive.
Why I can't change directories using "cd"?
This combines the answer by Serge with an unrelated answer by David. It changes the directory, and then instead of forcing a bash shell, it launches the user's default shell. It however requires both getent
and /etc/passwd
to detect the default shell.
#!/usr/bin/env bash
cd desired/directory
USER_SHELL=$(getent passwd <USER> | cut -d : -f 7)
$USER_SHELL
Of course this still has the same deficiency of creating a nested shell.
Twitter Bootstrap Form File Element Upload Button
In respect of claviska answer - if you want to show uploaded file name in a basic file upload you can do it in inputs' onchange
event. Just use this code:
<label class="btn btn-default">
Browse...
<span id="uploaded-file-name" style="font-style: italic"></span>
<input id="file-upload" type="file" name="file"
onchange="$('#uploaded-file-name').text($('#file-upload')[0].value);" hidden>
</label>
This jquery JS code is responsible will retrieving uploaded file name:
$('#file-upload')[0].value
Or with vanilla JS:
document.getElementById("file-upload").value
Convert Pandas column containing NaNs to dtype `int`
If you absolutely want to combine integers and NaNs in a column, you can use the 'object' data type:
df['col'] = (
df['col'].fillna(0)
.astype(int)
.astype(object)
.where(df['col'].notnull())
)
This will replace NaNs with an integer (doesn't matter which), convert to int, convert to object and finally reinsert NaNs.
Querying data by joining two tables in two database on different servers
While I was having trouble join those two tables, I got away with doing exactly what I wanted by opening both remote databases at the same time. MySQL 5.6 (php 7.1) and the other MySQL 5.1 (php 5.6)
//Open a new connection to the MySQL server
$mysqli1 = new mysqli('server1','user1','password1','database1');
$mysqli2 = new mysqli('server2','user2','password2','database2');
//Output any connection error
if ($mysqli1->connect_error) {
die('Error : ('. $mysqli1->connect_errno .') '. $mysqli1->connect_error);
} else {
echo "DB1 open OK<br>";
}
if ($mysqli2->connect_error) {
die('Error : ('. $mysqli2->connect_errno .') '. $mysqli2->connect_error);
} else {
echo "DB2 open OK<br><br>";
}
If you get those two OKs on screen, then both databases are open and ready. Then you can proceed to do your querys.
$results = $mysqli1->query("SELECT * FROM video where video_id_old is NULL");
while($row = $results->fetch_array()) {
$theID = $row[0];
echo "Original ID : ".$theID." <br>";
$doInsert = $mysqli2->query("INSERT INTO video (...) VALUES (...)");
$doGetVideoID = $mysqli2->query("SELECT video_id, time_stamp from video where user_id = '".$row[13]."' and time_stamp = ".$row[28]." ");
while($row = $doGetVideoID->fetch_assoc()) {
echo "New video_id : ".$row["video_id"]." user_id : ".$row["user_id"]." time_stamp : ".$row["time_stamp"]."<br>";
$sql = "UPDATE video SET video_id_old = video_id, video_id = ".$row["video_id"]." where user_id = '".$row["user_id"]."' and video_id = ".$theID.";";
$sql .= "UPDATE video_audio SET video_id = ".$row["video_id"]." where video_id = ".$theID.";";
// Execute multi query if you want
if (mysqli_multi_query($mysqli1, $sql)) {
// Query successful do whatever...
}
}
}
// close connection
$mysqli1->close();
$mysqli2->close();
I was trying to do some joins but since I got those two DBs open, then I can go back and forth doing querys by just changing the connection $mysqli1
or $mysqli2
It worked for me, I hope it helps... Cheers
How to write inside a DIV box with javascript
You can use one of the following methods:
document.getElementById('log').innerHTML = "text";
document.getElementById('log').innerText = "text";
document.getElementById('log').textContent = "text";
For Jquery:
$("#log").text("text");
$("#log").html("text");
Programmatically Check an Item in Checkboxlist where text is equal to what I want
I tried adding dynamically created ListItem and assigning the selected value.
foreach(var item in yourListFromDB)
{
ListItem listItem = new ListItem();
listItem.Text = item.name;
listItem.Value = Convert.ToString(item.value);
listItem.Selected=item.isSelected;
checkedListBox1.Items.Add(listItem);
}
checkedListBox1.DataBind();
avoid using binding the DataSource as it will not bind the checked/unchecked from DB.
Accessing Object Memory Address
While it's true that id(object)
gets the object's address in the default CPython implementation, this is generally useless... you can't do anything with the address from pure Python code.
The only time you would actually be able to use the address is from a C extension library... in which case it is trivial to get the object's address since Python objects are always passed around as C pointers.
How to check for file lock?
You could call LockFile via interop on the region of file you are interested in. This will not throw an exception, if it succeeds you will have a lock on that portion of the file (which is held by your process), that lock will be held until you call UnlockFile or your process dies.
What's the purpose of git-mv?
There's another use I have for git mv
not mentioned above.
Since discovering git add -p
(git add's patch mode; see http://git-scm.com/docs/git-add), I like to use it to review changes as I add them to the index. Thus my workflow becomes (1) work on code, (2) review and add to index, (3) commit.
How does git mv
fit in? If moving a file directly then using git rm
and git add
, all changes get added to the index, and using git diff to view changes is less easy (before committing). Using git mv
, however, adds the new path to the index but not changes made to the file, thus allowing git diff
and git add -p
to work as usual.
git clone from another directory
It's as easy as it looks.
14:27:05 ~$ mkdir gittests
14:27:11 ~$ cd gittests/
14:27:13 ~/gittests$ mkdir localrepo
14:27:20 ~/gittests$ cd localrepo/
14:27:21 ~/gittests/localrepo$ git init
Initialized empty Git repository in /home/andwed/gittests/localrepo/.git/
14:27:22 ~/gittests/localrepo (master #)$ cd ..
14:27:35 ~/gittests$ git clone localrepo copyoflocalrepo
Cloning into 'copyoflocalrepo'...
warning: You appear to have cloned an empty repository.
done.
14:27:42 ~/gittests$ cd copyoflocalrepo/
14:27:46 ~/gittests/copyoflocalrepo (master #)$ git status
On branch master
Initial commit
nothing to commit (create/copy files and use "git add" to track)
14:27:46 ~/gittests/copyoflocalrepo (master #)$
BackgroundWorker vs background Thread
A background worker is a class that works in a separate thread, but it provides additional functionality that you don't get with a simple Thread (like task progress report handling).
If you don't need the additional features given by a background worker - and it seems you don't - then a Thread would be more appropriate.
It says that TypeError: document.getElementById(...) is null
Make sure the script is placed in the bottom of the BODY element of the document you're trying to manipulate, not in the HEAD element or placed before any of the elements you want to "get".
It does not matter if you import the script or if it's inline, the important thing is the placing. You don't have to put the command inside a function either; while it's good practice you can just call it directly, it works just fine.
Android ListView Text Color
Ok, here are some things that you should be clear about:
- The background color you are setting in your xml file is of the activity and not of the ListItems you are trying to define.
- Every list item has its own layout file which should be passed or inflated in case you are using complex layout for list item.
I'll try to explain this with a code sample:
****Lets start with ListItems layout** : save it in your res/layout
folder of you Android project with say **list_black_text.xml
<?xml version="1.0" encoding="utf-8"?>
<!-- Definig a container for you List Item-->
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:gravity="center_vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!-- Defining where should text be placed. You set you text color here-->
<TextView
android:id="@+id/list_content"
android:textColor="#000000"
android:gravity="center"
android:text="sample"
android:layout_margin="4dip"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>
Well, a simple layout with a TextView
to be precise. You must have an id assigned to TextView in order to use it.
Now coming to you screen/activity/chief layout, as I said you are defining background to your screen with android:background
attribute. I see you have defined a TextView there as well and I suspect you are trying to define content/list item there, which is not at all needed.
Here's your edited layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#FFFFFF">
<ListView
android:id="@android:id/list" android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
<!-- REMOVED TEXT VIEW, AND KEEPING BACKGROUND WHITE -->
</LinearLayout>
And lastly, most importantly, set your adapter.
setListAdapter(new ArrayAdapter<String>(
this, R.layout.list_black_text, R.id.list_content, listItems));
Notice the layout resource which we are passing to adapter R.layout.list_black_text
, and R.id.list_content
which is TextView ID we declared. I have also changed ArrayAdapter to String type since it's generic.
I hope this explains everything. Mark my answer accepted if you agree.
Messy but a good quick fix way
You can also do this with a quick fix if you do not want to go ahead with complex layout defining etc.
While instantiating the adapter declare an inner class to do this, here is the code sample:
ArrayAdapter<String> adapter=new ArrayAdapter<String>(
this, android.R.layout.simple_list_item_1, listItems){
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view =super.getView(position, convertView, parent);
TextView textView=(TextView) view.findViewById(android.R.id.text1);
/*YOUR CHOICE OF COLOR*/
textView.setTextColor(Color.BLUE);
return view;
}
};
/*SET THE ADAPTER TO LISTVIEW*/
setListAdapter(adapter);
How to get the nth occurrence in a string?
a simple solution just add string, character and idx:
function getCharIdx(str,char,n){
let r = 0
for (let i = 0; i<str.length; i++){
if (str[i] === char){
r++
if (r === n){
return i
}
}
}
}
RGB to hex and hex to RGB
A simple answer for rgb to hex
function rgbtohex(r,g,b){
return "#" + (Math.round(r) * 65536 + Math.round(g) * 256 + Math.round(b)).toString(16));
}
How can I find script's directory?
Try sys.path[0]
.
To quote from the Python docs:
As initialized upon program startup, the first item of this list, path[0]
, is the directory containing the script that was used to invoke the Python interpreter. If the script directory is not available (e.g. if the interpreter is invoked interactively or if the script is read from standard input), path[0]
is the empty string, which directs Python to search modules in the current directory first. Notice that the script directory is inserted before the entries inserted as a result of PYTHONPATH
.
Source: https://docs.python.org/library/sys.html#sys.path
How can I create a table with borders in Android?
To make 1dp collapse-border around every cell without writing a java code and without creating another xml layout with <shape...>
tag, you can try this solution:
In <TableLayout...>
add
android:background="#CCC"
and android:paddingTop="1dp"
and android:stretchColumns="0"
In <TableRow...>
add
android:background="#CCC"
and android:paddingBottom="1dp"
and android:paddingRight="1dp"
In every cell/child in TableRow, i.e. <TextView...>
add
android:background="#FFF"
and android:layout_marginLeft="1dp"
It is very important to follow paddings and margins as described. This solution will draw a 1dp border aka border-collapse property in (X)HTML/CSS.
Background color in <TableLayout...>
and <TableRow...>
represents a border line color and background in <TextView...>
fills a table cell. You can put some padding in cells if necessary.
An example is here:
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#CCC"
android:paddingTop="1dp"
android:stretchColumns="0"
android:id="@+id/tlTable01">
<TableRow
android:background="#CCC"
android:paddingBottom="1dp"
android:paddingRight="1dp">
<TextView
android:layout_marginLeft="1dp"
android:padding="5dp"
android:background="#FFF"
android:text="Item1"/>
<TextView
android:layout_marginLeft="1dp"
android:padding="5dp"
android:background="#FFF"
android:gravity="right"
android:text="123456"/>
</TableRow>
<TableRow
android:background="#CCC"
android:paddingBottom="1dp"
android:paddingRight="1dp">
<TextView
android:layout_marginLeft="1dp"
android:padding="5dp"
android:background="#FFF"
android:text="Item2"/>
<TextView
android:layout_marginLeft="1dp"
android:padding="5dp"
android:background="#FFF"
android:gravity="right"
android:text="456789"/>
</TableRow>
</TableLayout>
What exactly is std::atomic?
Each instantiation and full specialization of std::atomic<> represents a type that different threads can simultaneously operate on (their instances), without raising undefined behavior:
Objects of atomic types are the only C++ objects that are free from data races; that is, if one thread writes to an atomic object while another thread reads from it, the behavior is well-defined.
In addition, accesses to atomic objects may establish inter-thread synchronization and order non-atomic memory accesses as specified by std::memory_order
.
std::atomic<>
wraps operations that, in pre-C++ 11 times, had to be performed using (for example) interlocked functions with MSVC or atomic bultins in case of GCC.
Also, std::atomic<>
gives you more control by allowing various memory orders that specify synchronization and ordering constraints. If you want to read more about C++ 11 atomics and memory model, these links may be useful:
Note that, for typical use cases, you would probably use overloaded arithmetic operators or another set of them:
std::atomic<long> value(0);
value++; //This is an atomic op
value += 5; //And so is this
Because operator syntax does not allow you to specify the memory order, these operations will be performed with std::memory_order_seq_cst
, as this is the default order for all atomic operations in C++ 11. It guarantees sequential consistency (total global ordering) between all atomic operations.
In some cases, however, this may not be required (and nothing comes for free), so you may want to use more explicit form:
std::atomic<long> value {0};
value.fetch_add(1, std::memory_order_relaxed); // Atomic, but there are no synchronization or ordering constraints
value.fetch_add(5, std::memory_order_release); // Atomic, performs 'release' operation
Now, your example:
a = a + 12;
will not evaluate to a single atomic op: it will result in a.load()
(which is atomic itself), then addition between this value and 12
and a.store()
(also atomic) of final result. As I noted earlier, std::memory_order_seq_cst
will be used here.
However, if you write a += 12
, it will be an atomic operation (as I noted before) and is roughly equivalent to a.fetch_add(12, std::memory_order_seq_cst)
.
As for your comment:
A regular int
has atomic loads and stores. Whats the point of wrapping it with atomic<>
?
Your statement is only true for architectures that provide such guarantee of atomicity for stores and/or loads. There are architectures that do not do this. Also, it is usually required that operations must be performed on word-/dword-aligned address to be atomic std::atomic<>
is something that is guaranteed to be atomic on every platform, without additional requirements. Moreover, it allows you to write code like this:
void* sharedData = nullptr;
std::atomic<int> ready_flag = 0;
// Thread 1
void produce()
{
sharedData = generateData();
ready_flag.store(1, std::memory_order_release);
}
// Thread 2
void consume()
{
while (ready_flag.load(std::memory_order_acquire) == 0)
{
std::this_thread::yield();
}
assert(sharedData != nullptr); // will never trigger
processData(sharedData);
}
Note that assertion condition will always be true (and thus, will never trigger), so you can always be sure that data is ready after while
loop exits. That is because:
store()
to the flag is performed after sharedData
is set (we assume that generateData()
always returns something useful, in particular, never returns NULL
) and uses std::memory_order_release
order:
memory_order_release
A store operation with this memory order performs the release
operation: no reads or writes in the current thread can be reordered
after this store. All writes in the current thread are visible in
other threads that acquire the same atomic variable
sharedData
is used after while
loop exits, and thus after load()
from flag will return a non-zero value. load()
uses std::memory_order_acquire
order:
std::memory_order_acquire
A load operation with this memory order performs the acquire operation
on the affected memory location: no reads or writes in the current
thread can be reordered before this load. All writes in other threads
that release the same atomic variable are visible in the current
thread.
This gives you precise control over the synchronization and allows you to explicitly specify how your code may/may not/will/will not behave. This would not be possible if only guarantee was the atomicity itself. Especially when it comes to very interesting sync models like the release-consume ordering.
How to count items in JSON data
import json
json_data = json.dumps({
"result":[
{
"run":[
{
"action":"stop"
},
{
"action":"start"
},
{
"action":"start"
}
],
"find": "true"
}
]
})
item_dict = json.loads(json_data)
print len(item_dict['result'][0]['run'])
Convert it in dict.
Download File Using Javascript/jQuery
function downloadURI(uri, name)
{
var link = document.createElement("a");
// If you don't know the name or want to use
// the webserver default set name = ''
link.setAttribute('download', name);
link.href = uri;
document.body.appendChild(link);
link.click();
link.remove();
}
Check if your target browser(s) will run the above snippet smoothly:
http://caniuse.com/#feat=download
Remove a data connection from an Excel 2010 spreadsheet in compatibility mode
I had the same problem. Get the warning. Went to Data connections and deleted connection. Save, close reopen. Still get the warning.
I use a xp/vista menu plugin for classic menus. I found under data, get external data, properties, uncheck the save query definition. Save close and reopen.
That seemed to get rid of the warning.
Just removing the connection does not work. You have to get rid of the query.
Refresh Excel VBA Function Results
The Application.Volatile
doesn't work for recalculating a formula with my own function inside. I use the following function:
Application.CalculateFull
Read input numbers separated by spaces
By default, cin
reads from the input discarding any spaces. So, all you have to do is to use a do while
loop to read the input more than one time:
do {
cout<<"Enter a number, or numbers separated by a space, between 1 and 1000."<<endl;
cin >> num;
// reset your variables
// your function stuff (calculations)
}
while (true); // or some condition
How to get row count using ResultSet in Java?
I just made a getter method.
public int getNumberRows(){
try{
statement = connection.creatStatement();
resultset = statement.executeQuery("your query here");
if(resultset.last()){
return resultset.getRow();
} else {
return 0; //just cus I like to always do some kinda else statement.
}
} catch (Exception e){
System.out.println("Error getting row count");
e.printStackTrace();
}
return 0;
}
Why maven? What are the benefits?
Maven is a powerful project management tool that is based on POM (project object model). It is used for projects build, dependency and documentation.
It simplifies the build process like ANT. But it is too much advanced than ANT.
Maven helps to manage-
Builds,Documentation,Reporing,SCMs,Releases,Distribution.
- maven repository is a directory of packaged JAR file with pom.xml file. Maven searches for dependencies in the repositories.
Apply pandas function to column to create multiple new columns?
This is the correct and easiest way to accomplish this for 95% of use cases:
>>> df = pd.DataFrame(zip(*[range(10)]), columns=['num'])
>>> df
num
0 0
1 1
2 2
3 3
4 4
5 5
>>> def example(x):
... x['p1'] = x['num']**2
... x['p2'] = x['num']**3
... x['p3'] = x['num']**4
... return x
>>> df = df.apply(example, axis=1)
>>> df
num p1 p2 p3
0 0 0 0 0
1 1 1 1 1
2 2 4 8 16
3 3 9 27 81
4 4 16 64 256
How to create a temporary table in SSIS control flow task and then use it in data flow task?
Solution:
Set the property RetainSameConnection
on the Connection Manager
to True
so that temporary table created in one Control Flow task can be retained in another task.
Here is a sample SSIS package written in SSIS 2008 R2
that illustrates using temporary tables.
Walkthrough:
Create a stored procedure that will create a temporary table named ##tmpStateProvince
and populate with few records. The sample SSIS package will first call the stored procedure and then will fetch the temporary table data to populate the records into another database table. The sample package will use the database named Sora
Use the below create stored procedure script.
USE Sora;
GO
CREATE PROCEDURE dbo.PopulateTempTable
AS
BEGIN
SET NOCOUNT ON;
IF OBJECT_ID('TempDB..##tmpStateProvince') IS NOT NULL
DROP TABLE ##tmpStateProvince;
CREATE TABLE ##tmpStateProvince
(
CountryCode nvarchar(3) NOT NULL
, StateCode nvarchar(3) NOT NULL
, Name nvarchar(30) NOT NULL
);
INSERT INTO ##tmpStateProvince
(CountryCode, StateCode, Name)
VALUES
('CA', 'AB', 'Alberta'),
('US', 'CA', 'California'),
('DE', 'HH', 'Hamburg'),
('FR', '86', 'Vienne'),
('AU', 'SA', 'South Australia'),
('VI', 'VI', 'Virgin Islands');
END
GO
Create a table named dbo.StateProvince
that will be used as the destination table to populate the records from temporary table. Use the below create table script to create the destination table.
USE Sora;
GO
CREATE TABLE dbo.StateProvince
(
StateProvinceID int IDENTITY(1,1) NOT NULL
, CountryCode nvarchar(3) NOT NULL
, StateCode nvarchar(3) NOT NULL
, Name nvarchar(30) NOT NULL
CONSTRAINT [PK_StateProvinceID] PRIMARY KEY CLUSTERED
([StateProvinceID] ASC)
) ON [PRIMARY];
GO
Create an SSIS package using Business Intelligence Development Studio (BIDS)
. Right-click on the Connection Managers tab at the bottom of the package and click New OLE DB Connection...
to create a new connection to access SQL Server 2008 R2 database.
Click New...
on Configure OLE DB Connection Manager.
Perform the following actions on the Connection Manager dialog.
- Select
Native OLE DB\SQL Server Native Client 10.0
from Provider since the package will connect to SQL Server 2008 R2 database
- Enter the Server name, like
MACHINENAME\INSTANCE
- Select
Use Windows Authentication
from Log on to the server section or whichever you prefer.
- Select the database from
Select or enter a database name
, the sample uses the database name Sora
.
- Click
Test Connection
- Click
OK
on the Test connection succeeded message.
- Click
OK
on Connection Manager
The newly created data connection will appear on Configure OLE DB Connection Manager. Click OK
.
OLE DB connection manager KIWI\SQLSERVER2008R2.Sora
will appear under the Connection Manager tab at the bottom of the package. Right-click the connection manager and click Properties
Set the property RetainSameConnection
on the connection KIWI\SQLSERVER2008R2.Sora
to the value True
.
Right-click anywhere inside the package and then click Variables
to view the variables pane. Create the following variables.
A new variable named PopulateTempTable
of data type String
in the package scope SO_5631010
and set the variable with the value EXEC dbo.PopulateTempTable
.
A new variable named FetchTempData
of data type String
in the package scope SO_5631010
and set the variable with the value SELECT CountryCode, StateCode, Name FROM ##tmpStateProvince
Drag and drop an Execute SQL Task
on to the Control Flow tab. Double-click the Execute SQL Task to view the Execute SQL Task Editor.
On the General
page of the Execute SQL Task Editor, perform the following actions.
- Set the Name to
Create and populate temp table
- Set the Connection Type to
OLE DB
- Set the Connection to
KIWI\SQLSERVER2008R2.Sora
- Select
Variable
from SQLSourceType
- Select
User::PopulateTempTable
from SourceVariable
- Click
OK
Drag and drop a Data Flow Task
onto the Control Flow tab. Rename the Data Flow Task as Transfer temp data to database table
. Connect the green arrow from the Execute SQL Task to the Data Flow Task.
Double-click the Data Flow Task
to switch to Data Flow tab. Drag and drop an OLE DB Source
onto the Data Flow tab. Double-click OLE DB Source to view the OLE DB Source Editor.
On the Connection Manager
page of the OLE DB Source Editor, perform the following actions.
- Select
KIWI\SQLSERVER2008R2.Sora
from OLE DB Connection Manager
- Select
SQL command from variable
from Data access mode
- Select
User::FetchTempData
from Variable name
- Click
Columns
page
Clicking Columns
page on OLE DB Source Editor will display the following error because the table ##tmpStateProvince
specified in the source command variable does not exist and SSIS is unable to read the column definition.
To fix the error, execute the statement EXEC dbo.PopulateTempTable
using SQL Server Management Studio (SSMS) on the database Sora
so that the stored procedure will create the temporary table. After executing the stored procedure, click Columns
page on OLE DB Source Editor, you will see the column information. Click OK
.
Drag and drop OLE DB Destination
onto the Data Flow tab. Connect the green arrow from OLE DB Source to OLE DB Destination. Double-click OLE DB Destination
to open OLE DB Destination Editor.
On the Connection Manager
page of the OLE DB Destination Editor, perform the following actions.
- Select
KIWI\SQLSERVER2008R2.Sora
from OLE DB Connection Manager
- Select
Table or view - fast load
from Data access mode
- Select
[dbo].[StateProvince]
from Name of the table or the view
- Click
Mappings
page
Click Mappings
page on the OLE DB Destination Editor would automatically map the columns if the input and output column names are same. Click OK
. Column StateProvinceID
does not have a matching input column and it is defined as an IDENTITY
column in database. Hence, no mapping is required.
Data Flow tab should look something like this after configuring all the components.
Click the OLE DB Source
on Data Flow tab and press F4 to view Properties
. Set the property ValidateExternalMetadata
to False so that SSIS would not try to check for the existence of the temporary table during validation phase of the package execution.
Execute the query select * from dbo.StateProvince
in the SQL Server Management Studio (SSMS) to find the number of rows in the table. It should be empty before executing the package.
Execute the package. Control Flow shows successful execution.
In Data Flow tab, you will notice that the package successfully processed 6 rows. The stored procedure created early in this posted inserted 6 rows into the temporary table.
Execute the query select * from dbo.StateProvince
in the SQL Server Management Studio (SSMS) to find the 6 rows successfully inserted into the table. The data should match with rows founds in the stored procedure.
The above example illustrated how to create and use temporary table within a package.
How do I return the response from an asynchronous call?
Of course there are many approaches like synchronous request, promise, but from my experience I think you should use the callback approach. It's natural to asynchronous behavior of Javascript.
So, your code snippet can be rewrite a little different:
function foo() {
var result;
$.ajax({
url: '...',
success: function(response) {
myCallback(response);
}
});
return result;
}
function myCallback(response) {
// Does something.
}
C#: New line and tab characters in strings
StringBuilder sb = new StringBuilder();
sb.Append("Line 1");
sb.Append(System.Environment.NewLine); //Change line
sb.Append("\t"); //Add tabulation
sb.Append("Line 2");
using (StreamWriter sw = new StreamWriter("example.txt"))
{
sw.Write(sb.ToString());
}
You can find detailed documentation on TAB (and other escape character here).
What should my Objective-C singleton look like?
Per my other answer below, I think you should be doing:
+ (id)sharedFoo
{
static dispatch_once_t once;
static MyFoo *sharedFoo;
dispatch_once(&once, ^ { sharedFoo = [[self alloc] init]; });
return sharedFoo;
}
How to check if an integer is in a given range?
Google's Java Library Guava also implements Range:
import com.google.common.collect.Range;
Range<Integer> open = Range.open(1, 5);
System.out.println(open.contains(1)); // false
System.out.println(open.contains(3)); // true
System.out.println(open.contains(5)); // false
Range<Integer> closed = Range.closed(1, 5);
System.out.println(closed.contains(1)); // true
System.out.println(closed.contains(3)); // true
System.out.println(closed.contains(5)); // true
Range<Integer> openClosed = Range.openClosed(1, 5);
System.out.println(openClosed.contains(1)); // false
System.out.println(openClosed.contains(3)); // true
System.out.println(openClosed.contains(5)); // true
Scala: write string to file in one statement
Here's the modern, safe one liner:
java.nio.file.Files.write(java.nio.file.Paths.get("/tmp/output.txt"), "Hello world".getBytes());
nio is a modern IO library shipped by default with the JDK 9+ so no imports or dependencies required.
Convert seconds to HH-MM-SS with JavaScript?
Easy to follow version for noobies:
var totalNumberOfSeconds = YOURNUMBEROFSECONDS;
var hours = parseInt( totalNumberOfSeconds / 3600 );
var minutes = parseInt( (totalNumberOfSeconds - (hours * 3600)) / 60 );
var seconds = Math.floor((totalNumberOfSeconds - ((hours * 3600) + (minutes * 60))));
var result = (hours < 10 ? "0" + hours : hours) + ":" + (minutes < 10 ? "0" + minutes : minutes) + ":" + (seconds < 10 ? "0" + seconds : seconds);
console.log(result);
Making an array of integers in iOS
You can use a plain old C array:
NSInteger myIntegers[40];
for (NSInteger i = 0; i < 40; i++)
myIntegers[i] = i;
// to get one of them
NSLog (@"The 4th integer is: %d", myIntegers[3]);
Or, you can use an NSArray
or NSMutableArray
, but here you will need to wrap up each integer inside an NSNumber
instance (because NSArray
objects are designed to hold class instances).
NSMutableArray *myIntegers = [NSMutableArray array];
for (NSInteger i = 0; i < 40; i++)
[myIntegers addObject:[NSNumber numberWithInteger:i]];
// to get one of them
NSLog (@"The 4th integer is: %@", [myIntegers objectAtIndex:3]);
// or
NSLog (@"The 4th integer is: %d", [[myIntegers objectAtIndex:3] integerValue]);
Parameter "stratify" from method "train_test_split" (scikit Learn)
For my future self who comes here via Google:
train_test_split
is now in model_selection
, hence:
from sklearn.model_selection import train_test_split
# given:
# features: xs
# ground truth: ys
x_train, x_test, y_train, y_test = train_test_split(xs, ys,
test_size=0.33,
random_state=0,
stratify=ys)
is the way to use it. Setting the random_state
is desirable for reproducibility.
Setting UILabel text to bold
Use attributed string:
// Define attributes
let labelFont = UIFont(name: "HelveticaNeue-Bold", size: 18)
let attributes :Dictionary = [NSFontAttributeName : labelFont]
// Create attributed string
var attrString = NSAttributedString(string: "Foo", attributes:attributes)
label.attributedText = attrString
You need to define attributes.
Using attributed string you can mix colors, sizes, fonts etc within one text
EditText request focus
>>you can write your code like
if (TextUtils.isEmpty(username)) {
editTextUserName.setError("Please enter username");
editTextUserName.requestFocus();
return;
}
if (TextUtils.isEmpty(password)) {
editTextPassword.setError("Enter a password");
editTextPassword.requestFocus();
return;
}
Skip a submodule during a Maven build
It's possible to decide which reactor projects to build by specifying the -pl
command line argument:
$ mvn --help
[...]
-pl,--projects <arg> Build specified reactor projects
instead of all projects
[...]
It accepts a comma separated list of parameters in one of the following forms:
- relative path of the folder containing the POM
[groupId]:artifactId
Thus, given the following structure:
project-root [com.mycorp:parent]
|
+ --- server [com.mycorp:server]
| |
| + --- orm [com.mycorp.server:orm]
|
+ --- client [com.mycorp:client]
You can specify the following command line:
mvn -pl .,server,:client,com.mycorp.server:orm clean install
to build everything. Remove elements in the list to build only the modules you please.
EDIT: as blackbuild pointed out, as of Maven 3.2.1 you have a new -el
flag that excludes projects from the reactor, similarly to what -pl
does:
How to get a list of current open windows/process with Java?
The below program will be compatible with Java 9+ version only...
To get the CurrentProcess information,
public class CurrentProcess {
public static void main(String[] args) {
ProcessHandle handle = ProcessHandle.current();
System.out.println("Current Running Process Id: "+handle.pid());
ProcessHandle.Info info = handle.info();
System.out.println("ProcessHandle.Info : "+info);
}
}
For all running processes,
import java.util.List;
import java.util.stream.Collectors;
public class AllProcesses {
public static void main(String[] args) {
ProcessHandle.allProcesses().forEach(processHandle -> {
System.out.println(processHandle.pid()+" "+processHandle.info());
});
}
}
How to use a variable of one method in another method?
You can't. Variables defined inside a method are local to that method.
If you want to share variables between methods, then you'll need to specify them as member variables of the class. Alternatively, you can pass them from one method to another as arguments (this isn't always applicable).
Looks like you're using instance methods instead of static ones.
If you don't want to create an object, you should declare all your methods static, so something like
private static void methodName(Argument args...)
If you want a variable to be accessible by all these methods, you should initialise it outside the methods and to limit its scope, declare it private.
private static int[][] array = new int[3][5];
Global variables are usually looked down upon (especially for situations like your one) because in a large-scale program they can wreak havoc, so making it private will prevent some problems at the least.
Also, I'll say the usual: You should try to keep your code a bit tidy. Use descriptive class, method and variable names and keep your code neat (with proper indentation, linebreaks etc.) and consistent.
Here's a final (shortened) example of what your code should be like:
public class Test3 {
private static int[][] scores = new int[3][5];
private static void createScores() {
}
public static void main(String[] args){
createScores();
MD();
sumD();
}
}
Ideally, since you're using an array, you would create the array in the main method and pass it as an argument across each method, but explaining how that works is probably a whole new question on its own so I'll leave it at that.
Where does git config --global get written to?
I was also looking for the global .gitconfig
on my Windows machine and found this neat trick using git.
Do a: git config --global -e
and then, if you are lucky, you will get a text editor loaded with your global .gitconfig
file. Simply lookup the folder from there (or try a save as...), et voilà! :-)
How to fix/convert space indentation in Sublime Text?
I actually found it's better for my sanity to have user preferences to be defined like so:
"translate_tabs_to_spaces": true,
"tab_size": 2,
"indent_to_bracket": true,
"detect_indentation": false
The detect_indentation: false
is especially important, as it forces Sublime to honor these settings in every file, as opposed to the View -> Indentation
settings.
If you want to get fancy, you can also define a keyboard shortcut to automatically re-indent your code (YMMV) by pasting the following in Sublime -> Preferences -> Key Binding - User
:
[
{ "keys": ["ctrl+i"], "command": "reindent" }
]
and to visualize the whitespace:
"indent_guide_options": ["draw_active"],
"trim_trailing_white_space_on_save": true,
"ensure_newline_at_eof_on_save": true,
"draw_white_space": "all",
"rulers": [120],
how to get program files x86 env variable?
Another relevant environment variable is:
%ProgramW6432%
So, on a 64-bit machine running in 32-bit (WOW64) mode:
- echo %programfiles% ==> C:\Program Files (x86)
- echo %programfiles(x86)% ==> C:\Program Files (x86)
- echo %ProgramW6432% ==> C:\Program Files
From Wikipedia:
The %ProgramFiles% variable points to the Program Files directory,
which stores all the installed programs of Windows and others. The
default on English-language systems is "C:\Program Files". In 64-bit
editions of Windows (XP, 2003, Vista), there are also
%ProgramFiles(x86)%, which defaults to "C:\Program Files (x86)", and
%ProgramW6432%, which defaults to "C:\Program Files". The
%ProgramFiles% itself depends on whether the process requesting the
environment variable is itself 32-bit or 64-bit (this is caused by
Windows-on-Windows 64-bit redirection).
Reference: http://en.wikipedia.org/wiki/Environment_variable
IOS - How to segue programmatically using swift
You can use segue like this:
self.performSegueWithIdentifier("push", sender: self)
override func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {
if segue.identifier == "push" {
}
}
OwinStartup not firing
I think what some people were trying to get to above is that if you want to programatically make your OWIN server "come to life", you'd be calling something like this:
using Microsoft.Owin.Hosting;
IDisposable _server = WebApp.Start<StartupMethod>("http://+:5000");
// Start Accepting HTTP via all interfaces on port 5000
Once you make this call, you will see the call to StartupMethod() fire in the debugger
How do I deal with special characters like \^$.?*|+()[{ in my regex?
Escape with a double backslash
R treats backslashes as escape values for character constants. (... and so do regular expressions. Hence the need for two backslashes when supplying a character argument for a pattern. The first one isn't actually a character, but rather it makes the second one into a character.) You can see how they are processed using cat
.
y <- "double quote: \", tab: \t, newline: \n, unicode point: \u20AC"
print(y)
## [1] "double quote: \", tab: \t, newline: \n, unicode point: €"
cat(y)
## double quote: ", tab: , newline:
## , unicode point: €
Further reading: Escaping a backslash with a backslash in R produces 2 backslashes in a string, not 1
To use special characters in a regular expression the simplest method is usually to escape them with a backslash, but as noted above, the backslash itself needs to be escaped.
grepl("\\[", "a[b")
## [1] TRUE
To match backslashes, you need to double escape, resulting in four backslashes.
grepl("\\\\", c("a\\b", "a\nb"))
## [1] TRUE FALSE
The rebus
package contains constants for each of the special characters to save you mistyping slashes.
library(rebus)
OPEN_BRACKET
## [1] "\\["
BACKSLASH
## [1] "\\\\"
For more examples see:
?SpecialCharacters
Your problem can be solved this way:
library(rebus)
grepl(OPEN_BRACKET, "a[b")
Form a character class
You can also wrap the special characters in square brackets to form a character class.
grepl("[?]", "a?b")
## [1] TRUE
Two of the special characters have special meaning inside character classes: \
and ^
.
Backslash still needs to be escaped even if it is inside a character class.
grepl("[\\\\]", c("a\\b", "a\nb"))
## [1] TRUE FALSE
Caret only needs to be escaped if it is directly after the opening square bracket.
grepl("[ ^]", "a^b") # matches spaces as well.
## [1] TRUE
grepl("[\\^]", "a^b")
## [1] TRUE
rebus
also lets you form a character class.
char_class("?")
## <regex> [?]
Use a pre-existing character class
If you want to match all punctuation, you can use the [:punct:]
character class.
grepl("[[:punct:]]", c("//", "[", "(", "{", "?", "^", "$"))
## [1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE
stringi
maps this to the Unicode General Category for punctuation, so its behaviour is slightly different.
stri_detect_regex(c("//", "[", "(", "{", "?", "^", "$"), "[[:punct:]]")
## [1] TRUE TRUE TRUE TRUE TRUE FALSE FALSE
You can also use the cross-platform syntax for accessing a UGC.
stri_detect_regex(c("//", "[", "(", "{", "?", "^", "$"), "\\p{P}")
## [1] TRUE TRUE TRUE TRUE TRUE FALSE FALSE
Use \Q \E escapes
Placing characters between \\Q
and \\E
makes the regular expression engine treat them literally rather than as regular expressions.
grepl("\\Q.\\E", "a.b")
## [1] TRUE
rebus
lets you write literal blocks of regular expressions.
literal(".")
## <regex> \Q.\E
Don't use regular expressions
Regular expressions are not always the answer. If you want to match a fixed string then you can do, for example:
grepl("[", "a[b", fixed = TRUE)
stringr::str_detect("a[b", fixed("["))
stringi::stri_detect_fixed("a[b", "[")
How can I handle the warning of file_get_contents() function in PHP?
something like this:
public function get($curl,$options){
$context = stream_context_create($options);
$file = @file_get_contents($curl, false, $context);
$str1=$str2=$status=null;
sscanf($http_response_header[0] ,'%s %d %s', $str1,$status, $str2);
if($status==200)
return $file
else
throw new \Exception($http_response_header[0]);
}