Programs & Examples On #Brainfuck

Brainfuck (bf) is an esoteric, Turing-complete programming language famous for its minimalistic, eight-character syntax.

What is the worst programming language you ever worked with?

LabVIEW (is that even considered a language?)

It was horrible. If you want to broaden the term, HTML sucks too, as does XML.

Can a foreign key refer to a primary key in the same table?

Other answers have given clear enough examples of a record referencing another record in the same table.

There are even valid use cases for a record referencing itself in the same table. For example, a point of sale system accepting many tenders may need to know which tender to use for change when the payment is not the exact value of the sale. For many tenders that's the same tender, for others that's domestic cash, for yet other tenders, no form of change is allowed.

All this can be pretty elegantly represented with a single tender attribute which is a foreign key referencing the primary key of the same table, and whose values sometimes match the respective primary key of same record. In this example, the absence of value (also known as NULL value) might be needed to represent an unrelated meaning: this tender can only be used at its full value.

Popular relational database management systems support this use case smoothly.

Take-aways:

  1. When inserting a record, the foreign key reference is verified to be present after the insert, rather than before the insert.

  2. When inserting multiple records with a single statement, the order in which the records are inserted matters. The constraints are checked for each record separately.

  3. Certain other data patterns, such as those involving circular dependences on record level going through two or more tables, cannot be purely inserted at all, or at least not with all the foreign keys enabled, and they have to be established using a combination of inserts and updates (if they are truly necessary).

In PHP with PDO, how to check the final SQL parametrized query?

I check Query Log to see the exact query that was executed as prepared statement.

Get list of filenames in folder with Javascript

I use the following (stripped-down code) in Firefox 69.0 (on Ubuntu) to read a directory and show the image as part of a digital photo frame. The page is made in HTML, CSS, and JavaScript, and it is located on the same machine where I run the browser. The images are located on the same machine as well, so there is no viewing from "outside".

var directory = <path>;
var xmlHttp = new XMLHttpRequest();
xmlHttp.open('GET', directory, false); // false for synchronous request
xmlHttp.send(null);
var ret = xmlHttp.responseText;
var fileList = ret.split('\n');
for (i = 0; i < fileList.length; i++) {
    var fileinfo = fileList[i].split(' ');
    if (fileinfo[0] == '201:') {
        document.write(fileinfo[1] + "<br>");
        document.write('<img src=\"' + directory + fileinfo[1] + '\"/>');
    }
}

This requires the policy security.fileuri.strict_origin_policy to be disabled. This means it might not be a solution you want to use. In my case I deemed it ok.

Working with select using AngularJS's ng-options

In CoffeeScript:

#directive
app.directive('select2', ->
    templateUrl: 'partials/select.html'
    restrict: 'E'
    transclude: 1
    replace: 1
    scope:
        options: '='
        model: '='
    link: (scope, el, atr)->
        el.bind 'change', ->
            console.log this.value
            scope.model = parseInt(this.value)
            console.log scope
            scope.$apply()
)
<!-- HTML partial -->
<select>
  <option ng-repeat='o in options'
          value='{{$index}}' ng-bind='o'></option>
</select>

<!-- HTML usage -->
<select2 options='mnuOffline' model='offlinePage.toggle' ></select2>

<!-- Conclusion -->
<p>Sometimes it's much easier to create your own directive...</p>

Why was the name 'let' chosen for block-scoped variable declarations in JavaScript?

The most likely possibility is that it was the most idiomatic choice. Not only is it easy to speak, but rather intuitive to understand. Some could argue, even more so than var.

But I reckon there's a little more history to this.

From Wikipedia:

Dana Scott's LCF language was a stage in the evolution of lambda calculus into modern functional languages. This language introduced the let expression, which has appeared in most functional languages since that time.

State-full imperative languages such as ALGOL and Pascal essentially implement a let expression, to implement restricted scope of functions, in block structures.

I would like to believe this was an inspiration too, for the let in Javascript.

Where can I set path to make.exe on Windows?

The path is in the registry but usually you edit through this interface:

  1. Go to Control Panel -> System -> System settings -> Environment Variables.
  2. Scroll down in system variables until you find PATH.
  3. Click edit and change accordingly.
  4. BE SURE to include a semicolon at the end of the previous as that is the delimiter, i.e. c:\path;c:\path2
  5. Launch a new console for the settings to take effect.

Define global constants

I have another way to define global constants. Because if we defined in ts file, if build in production mode it is not easy to find constants to change value.

export class SettingService  {

  constructor(private http: HttpClient) {

  }

  public getJSON(file): Observable<any> {
      return this.http.get("./assets/configs/" + file + ".json");
  }
  public getSetting(){
      // use setting here
  }
}

In app folder, i add folder configs/setting.json

Content in setting.json

{
    "baseUrl": "http://localhost:52555"
}

In app module add APP_INITIALIZER

   {
      provide: APP_INITIALIZER,
      useFactory: (setting: SettingService) => function() {return setting.getSetting()},
      deps: [SettingService],
      multi: true
    }

with this way, I can change value in json file easier. I also use this way for constant error/warning messages.

What is @RenderSection in asp.net MVC

If

(1) you have a _Layout.cshtml view like this

<html>
    <body>
        @RenderBody()

    </body>
    <script type="text/javascript" src="~/lib/layout.js"></script>
    @RenderSection("scripts", required: false)
</html>

(2) you have Contacts.cshtml

@section Scripts{
    <script type="text/javascript" src="~/lib/contacts.js"></script>

}
<div class="row">
    <div class="col-md-6 col-md-offset-3">
        <h2>    Contacts</h2>
    </div>
</div>

(3) you have About.cshtml

<div class="row">
    <div class="col-md-6 col-md-offset-3">
        <h2>    Contacts</h2>
    </div>
</div>

On you layout page, if required is set to false "@RenderSection("scripts", required: false)", When page renders and user is on about page, the contacts.js doesn't render.

    <html>
        <body><div>About<div>             
        </body>
        <script type="text/javascript" src="~/lib/layout.js"></script>
    </html>

if required is set to true "@RenderSection("scripts", required: true)", When page renders and user is on ABOUT page, the contacts.js STILL gets rendered.

<html>
    <body><div>About<div>             
    </body>
    <script type="text/javascript" src="~/lib/layout.js"></script>
    <script type="text/javascript" src="~/lib/contacts.js"></script>
</html>

IN SHORT, when set to true, whether you need it or not on other pages, it will get rendered anyhow. If set to false, it will render only when the child page is rendered.

Declaring & Setting Variables in a Select Statement

Coming from SQL Server as well, and this really bugged me. For those using Toad Data Point or Toad for Oracle, it's extremely simple. Just putting a colon in front of your variable name will prompt Toad to open a dialog where you enter the value on execute.

SELECT * FROM some_table WHERE some_column = :var_name;

What is ViewModel in MVC?

A lot of big examples, let me explain in clear and crispy way.

ViewModel = Model that is created to serve the view.

ASP.NET MVC view can't have more than one model so if we need to display properties from more than one models into the view, it is not possible. ViewModel serves this purpose.

View Model is a model class that can hold only those properties that is required for a view. It can also contains properties from more than one entities (tables) of the database. As the name suggests, this model is created specific to the View requirements.

Few examples of View Models are below

  • To list data from more than entities in a view page – we can create a View model and have properties of all the entities for which we want to list data. Join those database entities and set View model properties and return to the View to show data of different entities in one tabular form
  • View model may define only specific fields of a single entity that is required for the View.

ViewModel can also be used to insert, update records into more than one entities however the main use of ViewModel is to display columns from multiple entities (model) into a single view.

The way of creating ViewModel is same as creating Model, the way of creating view for the Viewmodel is same as creating view for Model.

Here is a small example of List data using ViewModel.

Hope this will be useful.

Importing xsd into wsdl

You have a couple of problems here.

First, the XSD has an issue where an element is both named or referenced; in your case should be referenced.

Change:

<xsd:element name="stock" ref="Stock" minOccurs="1" maxOccurs="unbounded"/> 

To:

<xsd:element name="stock" type="Stock" minOccurs="1" maxOccurs="unbounded"/> 

And:

  • Remove the declaration of the global element Stock
  • Create a complex type declaration for a type named Stock

So:

<xsd:element name="Stock">
    <xsd:complexType>

To:

<xsd:complexType name="Stock">

Make sure you fix the xml closing tags.

The second problem is that the correct way to reference an external XSD is to use XSD schema with import/include within a wsdl:types element. wsdl:import is reserved to referencing other WSDL files. More information is available by going through the WS-I specification, section WSDL and Schema Import. Based on WS-I, your case would be:

INCORRECT: (the way you showed it)

<?xml version="1.0" encoding="UTF-8"?>
<definitions targetNamespace="http://stock.com/schemas/services/stock/wsdl"
    .....xmlns:external="http://stock.com/schemas/services/stock"
    <import namespace="http://stock.com/schemas/services/stock" location="Stock.xsd" />
    <message name="getStockQuoteResp">
        <part name="parameters" element="external:getStockQuoteResponse" />
    </message>
</definitions>

CORRECT:

<?xml version="1.0" encoding="UTF-8"?>
<definitions targetNamespace="http://stock.com/schemas/services/stock/wsdl"
    .....xmlns:external="http://stock.com/schemas/services/stock"
    <types>
        <schema xmlns="http://www.w3.org/2001/XMLSchema">
            <import namespace="http://stock.com/schemas/services/stock" schemaLocation="Stock.xsd" />             
        </schema>
    </types>
    <message name="getStockQuoteResp">
        <part name="parameters" element="external:getStockQuoteResponse" />
    </message>
</definitions>

SOME processors may support both syntaxes. The XSD you put out shows issues, make sure you first validate the XSD.

It would be better if you go the WS-I way when it comes to WSDL authoring.

Other issues may be related to the use of relative vs. absolute URIs in locating external content.

How can I remove the top and right axis in matplotlib?

This is the suggested Matplotlib 3 solution from the official website HERE:

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 2*np.pi, 100)
y = np.sin(x)

ax = plt.subplot(111)
ax.plot(x, y)

# Hide the right and top spines
ax.spines['right'].set_visible(False)
ax.spines['top'].set_visible(False)

# Only show ticks on the left and bottom spines
ax.yaxis.set_ticks_position('left')
ax.xaxis.set_ticks_position('bottom')

plt.show()

enter image description here

What is Options +FollowSymLinks?

How does the server know that it should pull image.png from the /pictures folder when you visit the website and browse to the /system/files/images folder in your web browser? A so-called symbolic link is the guy that is responsible for this behavior. Somewhere in your system, there is a symlink that tells your server "If a visitor requests /system/files/images/image.png then show him /pictures/image.png."

And what is the role of the FollowSymLinks setting in this?

FollowSymLinks relates to server security. When dealing with web servers, you can't just leave things undefined. You have to tell who has access to what. The FollowSymLinks setting tells your server whether it should or should not follow symlinks. In other words, if FollowSymLinks was disabled in our case, browsing to the /system/files/images/image.png file would return depending on other settings either the 403 (access forbidden) or 404 (not found) error.

http://www.maxi-pedia.com/FollowSymLinks

How to add an element to Array and shift indexes?

The most simple way of doing this is to use an ArrayList<Integer> and use the add(int, T) method.

List<Integer> list = new ArrayList<Integer>();
list.add(1);
list.add(2);
list.add(3);
list.add(4);
list.add(5);
list.add(6);

// Now, we will insert the number
list.add(4, 87);

error LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStartup

You appear to have no main function, which is supposed to be the entry-point for your program.

How to delete object from array inside foreach loop?

Be careful with the main answer.

with

[['id'=>1,'cat'=>'vip']
,['id'=>2,'cat'=>'vip']
,['id'=>3,'cat'=>'normal']

and calling the function

foreach($array as $elementKey => $element) {
    foreach($element as $valueKey => $value) {
        if($valueKey == 'cat' && $value == 'vip'){
            //delete this particular object from the $array
            unset($array[$elementKey]);
        } 
    }
}

it returns

[2=>['id'=>3,'cat'=>'normal']

instead of

[0=>['id'=>3,'cat'=>'normal']

It is because unset does not re-index the array.

It reindexes. (if we need it)

$result=[];
foreach($array as $elementKey => $element) {
    foreach($element as $valueKey => $value) {
        $found=false;
        if($valueKey === 'cat' && $value === 'vip'){
            $found=true;
            $break;
        } 
        if(!$found) {
           $result[]=$element;
        }
    }
}

Adding Google Play services version to your app's manifest?

It is probably that your library is not linked to project properly or that you have older google-play-services library version so conflict appears and Eclipse got stupid.. :S

No you don't need to add anything in integers.xml. When you link properly Google-play-services library to your project reference android:value="@integer/google_play_services_version" will be found and you are ready to go. When you add library to your project just do one more clean so funny Eclipse environment sweep-out things properly.

If you hardcode somewhere this number when next play version come you would need to update it. And if you forget that, you will spend time again looking for bug.. :S

Hope it helped. ;)

Numpy: Divide each row by a vector element

Pythonic way to do this is ...

np.divide(data.T,vector).T

This takes care of reshaping and also the results are in floating point format. In other answers results are in rounded integer format.

#NOTE: No of columns in both data and vector should match

How can I use a C++ library from node.js?

There is a fresh answer to that question now. SWIG, as of version 3.0 seems to provide javascript interface generators for Node.js, Webkit and v8.

I've been using SWIG extensively for Java and Python for a while, and once you understand how SWIG works, there is almost no effort(compared to ffi or the equivalent in the target language) needed for interfacing C++ code to the languages that SWIG supports.

As a small example, say you have a library with the header myclass.h:

#include<iostream>

class MyClass {
        int myNumber;
public:
        MyClass(int number): myNumber(number){}
        void sayHello() {
                std::cout << "Hello, my number is:" 
                << myNumber <<std::endl;
        }
};

In order to use this class in node, you simply write the following SWIG interface file (mylib.i):

%module "mylib"
%{
#include "myclass.h"
%}
%include "myclass.h"

Create the binding file binding.gyp:

{
  "targets": [
    {
      "target_name": "mylib",
      "sources": [ "mylib_wrap.cxx" ]
    }
  ]
}

Run the following commands:

swig -c++ -javascript -node mylib.i
node-gyp build

Now, running node from the same folder, you can do:

> var mylib = require("./build/Release/mylib")
> var c = new mylib.MyClass(5)
> c.sayHello()
Hello, my number is:5

Even though we needed to write 2 interface files for such a small example, note how we didn't have to mention the MyClass constructor nor the sayHello method anywhere, SWIG discovers these things, and automatically generates natural interfaces.

Timeout a command in bash without unnecessary delay

My problem was maybe a bit different : I start a command via ssh on a remote machine and want to kill the shell and childs if the command hangs.

I now use the following :

ssh server '( sleep 60 && kill -9 0 ) 2>/dev/null & my_command; RC=$? ; sleep 1 ; pkill -P $! ; exit $RC'

This way the command returns 255 when there was a timeout or the returncode of the command in case of success

Please note that killing processes from a ssh session is handled different from an interactive shell. But you can also use the -t option to ssh to allocate a pseudo terminal, so it acts like an interactive shell

Use <Image> with a local file

It works exactly as you expect it to work. There's a bug https://github.com/facebook/react-native/issues/282 that prevents it from working correctly.

If you have node_modules (with react_native) in the same folder as the xcode project, you can edit node_modules/react-native/packager/packager.js and make this change: https://github.com/facebook/react-native/pull/286/files . It'll work magically :)

If your react_native is installed somewhere else and the patch doesn't work, comment on https://github.com/facebook/react-native/issues/282 to let them know about your setup.

How do I remove diacritics (accents) from a string in .NET?

I often use an extenstion method based on another version I found here (see Replacing characters in C# (ascii)) A quick explanation:

  • Normalizing to form D splits charactes like è to an e and a nonspacing `
  • From this, the nospacing characters are removed
  • The result is normalized back to form C (I'm not sure if this is neccesary)

Code:

using System.Linq;
using System.Text;
using System.Globalization;

// namespace here
public static class Utility
{
    public static string RemoveDiacritics(this string str)
    {
        if (null == str) return null;
        var chars =
            from c in str.Normalize(NormalizationForm.FormD).ToCharArray()
            let uc = CharUnicodeInfo.GetUnicodeCategory(c)
            where uc != UnicodeCategory.NonSpacingMark
            select c;

        var cleanStr = new string(chars.ToArray()).Normalize(NormalizationForm.FormC);

        return cleanStr;
    }

    // or, alternatively
    public static string RemoveDiacritics2(this string str)
    {
        if (null == str) return null;
        var chars = str
            .Normalize(NormalizationForm.FormD)
            .ToCharArray()
            .Where(c=> CharUnicodeInfo.GetUnicodeCategory(c) != UnicodeCategory.NonSpacingMark)
            .ToArray();

        return new string(chars).Normalize(NormalizationForm.FormC);
    }
}

How do I remove quotes from a string?

str_replace('"', "", $string);
str_replace("'", "", $string);

I assume you mean quotation marks?

Otherwise, go for some regex, this will work for html quotes for example:

preg_replace("/<!--.*?-->/", "", $string);

C-style quotes:

preg_replace("/\/\/.*?\n/", "\n", $string);

CSS-style quotes:

preg_replace("/\/*.*?\*\//", "", $string);

bash-style quotes:

preg-replace("/#.*?\n/", "\n", $string);

Etc etc...

invalid conversion from 'const char*' to 'char*'

string::c.str() returns a string of type const char * as seen here

A quick fix: try casting printfunc(num,addr,(char *)data.str().c_str());

While the above may work, it is undefined behaviour, and unsafe.

Here's a nicer solution using templates:

char * my_argument = const_cast<char*> ( ...c_str() );

What is the best way to use a HashMap in C++?

Here's a more complete and flexible example that doesn't omit necessary includes to generate compilation errors:

#include <iostream>
#include <unordered_map>

class Hashtable {
    std::unordered_map<const void *, const void *> htmap;

public:
    void put(const void *key, const void *value) {
            htmap[key] = value;
    }

    const void *get(const void *key) {
            return htmap[key];
    }

};

int main() {
    Hashtable ht;
    ht.put("Bob", "Dylan");
    int one = 1;
    ht.put("one", &one);
    std::cout << (char *)ht.get("Bob") << "; " << *(int *)ht.get("one");
}

Still not particularly useful for keys, unless they are predefined as pointers, because a matching value won't do! (However, since I normally use strings for keys, substituting "string" for "const void *" in the declaration of the key should resolve this problem.)

Full width image with fixed height

If you don't want to lose the ratio of your image, then don't bother with height:300px; and just use width:100%;.

If the image is too large, then you will have to crop it using an image editor.

How to make Python script run as service?

I offer two recommendations:

supervisord

1) Install the supervisor package (more verbose instructions here):

sudo apt-get install supervisor

2) Create a config file for your daemon at /etc/supervisor/conf.d/flashpolicyd.conf:

[program:flashpolicyd]
directory=/path/to/project/root
environment=ENV_VARIABLE=example,OTHER_ENV_VARIABLE=example2
command=python flashpolicyd.py
autostart=true
autorestart=true

3) Restart supervisor to load your new .conf

supervisorctl update
supervisorctl restart flashpolicyd

systemd (if currently used by your Linux distro)

[Unit]
Description=My Python daemon

[Service]
Type=simple
ExecStart=/usr/bin/python3 /opt/project/main.py
WorkingDirectory=/opt/project/
Environment=API_KEY=123456789
Environment=API_PASS=password
Restart=always
RestartSec=2

[Install]
WantedBy=sysinit.target

Place this file into /etc/systemd/system/my_daemon.service and enable it using systemctl daemon-reload && systemctl enable my_daemon && systemctl start my_daemon --no-block.

To view logs:

systemctl status my_daemon

Change working directory in my current shell context when running Node script

There is no built-in method for Node to change the CWD of the underlying shell running the Node process.

You can change the current working directory of the Node process through the command process.chdir().

var process = require('process');
process.chdir('../');

When the Node process exists, you will find yourself back in the CWD you started the process in.

What is the point of the diamond operator (<>) in Java 7?

This line causes the [unchecked] warning:

List<String> list = new LinkedList();

So, the question transforms: why [unchecked] warning is not suppressed automatically only for the case when new collection is created?

I think, it would be much more difficult task then adding <> feature.

UPD: I also think that there would be a mess if it were legally to use raw types 'just for a few things'.

Regular expression negative lookahead

A negative lookahead says, at this position, the following regex can not match.

Let's take a simplified example:

a(?!b(?!c))

a      Match: (?!b) succeeds
ac     Match: (?!b) succeeds
ab     No match: (?!b(?!c)) fails
abe    No match: (?!b(?!c)) fails
abc    Match: (?!b(?!c)) succeeds

The last example is a double negation: it allows a b followed by c. The nested negative lookahead becomes a positive lookahead: the c should be present.

In each example, only the a is matched. The lookahead is only a condition, and does not add to the matched text.

Use jQuery to get the file input's selected filename without the path

Here is how I do it, it works pretty well.

In your HTML do:

<input type="file" name="Att_AttributeID" onchange="fileSelect(event)" class="inputField" />

Then in your js file create a simple function:

function fileSelect(id, e){
    console.log(e.target.files[0].name);
}

If you're doing multiple files, you should also be able to get the list by looping over this:

e.target.files[0].name

How to call Stored Procedures with EntityFramework?

This is what I recently did for my Data Visualization Application which has a 2008 SQL Database. In this example I am recieving a list returned from a stored procedure:

public List<CumulativeInstrumentsDataRow> GetCumulativeInstrumentLogs(RunLogFilter filter)
    {
        EFDbContext db = new EFDbContext();
        if (filter.SystemFullName == string.Empty)
        {
            filter.SystemFullName = null;
        }
        if (filter.Reconciled == null)
        {
            filter.Reconciled = 1;
        }
        string sql = GetRunLogFilterSQLString("[dbo].[rm_sp_GetCumulativeInstrumentLogs]", filter);
        return db.Database.SqlQuery<CumulativeInstrumentsDataRow>(sql).ToList();
    }

And then this extension method for some formatting in my case:

public string GetRunLogFilterSQLString(string procedureName, RunLogFilter filter)
        {
            return string.Format("EXEC {0} {1},{2}, {3}, {4}", procedureName, filter.SystemFullName == null ? "null" : "\'" + filter.SystemFullName + "\'", filter.MinimumDate == null ? "null" : "\'" + filter.MinimumDate.Value + "\'", filter.MaximumDate == null ? "null" : "\'" + filter.MaximumDate.Value + "\'", +filter.Reconciled == null ? "null" : "\'" + filter.Reconciled + "\'");

        }

How to draw an empty plot?

There is an interest in your solution that plot.new() hasn't though: in the empty plot you "draw" you can write text at specified coordinates with text(x = ..., y = ..., your_text).

Convert ascii value to char

for (int i = 0; i < 5; i++){
    int asciiVal = rand()%26 + 97;
    char asciiChar = asciiVal;
    cout << asciiChar << " and ";
}

Bootstrap Navbar toggle button not working

If you will change the ID then Toggle will not working same problem was with me i just change

<div class="collapse navbar-collapse" id="defaultNavbar1">
    <ul class="nav navbar-nav">

id="defaultNavbar1" then toggle is working

How to work with string fields in a C struct?

On strings and memory allocation:

A string in C is just a sequence of chars, so you can use char * or a char array wherever you want to use a string data type:

typedef struct     {
  int number;
  char *name;
  char *address;
  char *birthdate;
  char gender;
} patient;

Then you need to allocate memory for the structure itself, and for each of the strings:

patient *createPatient(int number, char *name, 
  char *addr, char *bd, char sex) {

  // Allocate memory for the pointers themselves and other elements
  // in the struct.
  patient *p = malloc(sizeof(struct patient));

  p->number = number; // Scalars (int, char, etc) can simply be copied

  // Must allocate memory for contents of pointers.  Here, strdup()
  // creates a new copy of name.  Another option:
  // p->name = malloc(strlen(name)+1);
  // strcpy(p->name, name);
  p->name = strdup(name);
  p->address = strdup(addr);
  p->birthdate = strdup(bd);
  p->gender = sex;
  return p;
}

If you'll only need a few patients, you can avoid the memory management at the expense of allocating more memory than you really need:

typedef struct     {
  int number;
  char name[50];       // Declaring an array will allocate the specified
  char address[200];   // amount of memory when the struct is created,
  char birthdate[50];  // but pre-determines the max length and may
  char gender;         // allocate more than you need.
} patient;

On linked lists:

In general, the purpose of a linked list is to prove quick access to an ordered collection of elements. If your llist contains an element called num (which presumably contains the patient number), you need an additional data structure to hold the actual patients themselves, and you'll need to look up the patient number every time.

Instead, if you declare

typedef struct llist
{
  patient *p;
  struct llist *next;
} list;

then each element contains a direct pointer to a patient structure, and you can access the data like this:

patient *getPatient(list *patients, int num) {
  list *l = patients;
  while (l != NULL) {
    if (l->p->num == num) {
      return l->p;
    }
    l = l->next;
  }
  return NULL;
}

Remove all whitespace from C# string with regex

Fastest and general way to do this (line terminators, tabs will be processed as well). Regex powerful facilities don't really needed to solve this problem, but Regex can decrease performance.

                       new string
                           (stringToRemoveWhiteSpaces
                                .Where
                                (
                                    c => !char.IsWhiteSpace(c)
                                )
                                .ToArray<char>()
                           )

OR

                       new string
                           (stringToReplaceWhiteSpacesWithSpace
                                .Select
                                (
                                    c => char.IsWhiteSpace(c) ? ' ' : c
                                )
                                .ToArray<char>()
                           )

Set Background cell color in PHPExcel

function cellColor($cells,$color){
    global $objPHPExcel;

    $objPHPExcel->getActiveSheet()->getStyle($cells)->getFill()->applyFromArray(array(
        'type' => PHPExcel_Style_Fill::FILL_SOLID,
        'startcolor' => array(
             'rgb' => $color
        )
    ));
}

cellColor('B5', 'F28A8C');
cellColor('G5', 'F28A8C');
cellColor('A7:I7', 'F28A8C');
cellColor('A17:I17', 'F28A8C');
cellColor('A30:Z30', 'F28A8C');

enter image description here

Iterating over Numpy matrix rows to apply a function each?

Use numpy.apply_along_axis(). Assuming your matrix is 2D, you can use like:

import numpy as np
mymatrix = np.matrix([[11,12,13],
                      [21,22,23],
                      [31,32,33]])
def myfunction( x ):
    return sum(x)

print np.apply_along_axis( myfunction, axis=1, arr=mymatrix )
#[36 66 96]

Visual Studio Code compile on save

Select Preferences -> Workspace Settings and add the following code, If you have Hot reload enabled, then the changes reflect immediately in the browser

{
    "files.exclude": {
        "**/.git": true,
        "**/.DS_Store": true,
        "**/*.js.map": true,
        "**/*.js": {"when": "$(basename).ts"}
    },
    "files.autoSave": "afterDelay",
    "files.autoSaveDelay": 1000
}

Center form submit buttons HTML / CSS

I'm assuming that the buttons are supposed to be next to each other on the same line, they should not each be centered using the 'auto' margin, but placed inside a div with a defined width that has a margin '0 auto':

CSS:

#centerbuttons{
   width:250px; 
   margin:0 auto;
}       

HTML (after removing the margin properties from your buttons' CSS):

<div id="centerbuttons">
     <input value="Search" title="Search" type="submit"> 
     <input value="I'm Feeling Lucky" title="I'm Feeling Lucky" name="lucky" type="submit">
</div>

Hide HTML element by id

If you want to do it via javascript rather than CSS you can use:

var link = document.getElementById('nav-ask');
link.style.display = 'none'; //or
link.style.visibility = 'hidden';

depending on what you want to do.

Send email with PHP from html form on submit with the same script

You can also use mandrill app to send the mail in php. You will get the API from https://mandrillapp.com/api/docs/index.php.html where you can find the complete details about emails sended and other details.

How to horizontally center an element

HTML:

<div id="outer">
  <div id="inner">
  </div>
</div>

CSS:

#outer{
  width: 500px;
  background-color: #000;
  height: 500px
}
#inner{
  background-color: #333;
  margin: 0 auto;
  width: 50%;
  height: 250px;
}

Fiddle.

Single vs double quotes in JSON

you can use ast.literal_eval()

>>> import ast
>>> s = "{'username':'dfdsfdsf'}"
>>> ast.literal_eval(s)
{'username': 'dfdsfdsf'}

prevent refresh of page when button inside form clicked

Let getData() return false. This will fix it.

<form method="POST">
    <button name="data" onclick="return getData()">Click</button>
</form>

How to store Configuration file and read it using React

If you used Create React App, you can set an environment variable using a .env file. The documentation is here:

https://facebook.github.io/create-react-app/docs/adding-custom-environment-variables

Basically do something like this in the .env file at the project root.

REACT_APP_NOT_SECRET_CODE=abcdef

Note that the variable name must start with REACT_APP_

You can access it from your component with

process.env.REACT_APP_NOT_SECRET_CODE

Filtering by Multiple Specific Model Properties in AngularJS (in OR relationship)

If you're open to use third party libraries,'Angular Filters' with a nice collection of filters may be useful:

https://github.com/a8m/angular-filter#filterby

collection | filterBy: [prop, nested.prop, etc..]: search

nodeJS - How to create and read session with express

Steps I did:

  1. Include the angular-cookies.js file in the HTML!
  2. Init cookies as being NOT http-only in server-side app.'s:

    app.configure(function(){
       //a bunch of stuff
       app.use(express.cookieSession({secret: 'mySecret', store: store, cookie: cookieSettings}));```
    
  3. Then in client-side services.jss I put ['ngCookies'] in like this:

    angular.module('swrp', ['ngCookies']).//etc

  4. Then in controller.js, in my function UserLoginCtrl, I have $cookies in there with $scope at the top like so:

    function UserLoginCtrl($scope, $cookies, socket) {

  5. Lastly, to get the value of a cookie inside the controller function I did:

    var mySession = $cookies['connect.sess'];

Now you can send that back to the server from the client. Awesome. Wish they would've put this in the Angular.js documentation. I figured it out by just reading the actual code for angular-cookies.js directly.

Passing properties by reference in C#

This is covered in section 7.4.1 of the C# language spec. Only a variable-reference can be passed as a ref or out parameter in an argument list. A property does not qualify as a variable reference and hence cannot be used.

Can't install any packages in Node.js using "npm install"

I found the there is a certificate expired issue with:

npm set registry https://registry.npmjs.org/

So I made it http, not https :-

npm set registry http://registry.npmjs.org/

And have no problems so far.

Variables as commands in bash scripts

I am not sure, but it might be worth running an eval on the commands first.

This will let bash expand the variables $TAR_CMD and such to their full breadth(just as the echo command does to the console, which you say works)

Bash will then read the line a second time with the variables expanded.

eval $TAR_CMD | $ENCRYPT_CMD | $SPLIT_CMD 

I just did a Google search and this page looks like it might do a decent job at explaining why that is needed. http://fvue.nl/wiki/Bash:_Why_use_eval_with_variable_expansion%3F

How to select a CRAN mirror in R

You could also disable all graphical menus by running this or placing it in your Rprofile

options(menu.graphics = FALSE)

How to change scroll bar position with CSS?

Try this out. Hope this helps

<div id="single" dir="rtl">
    <div class="common">Single</div>
</div>

<div id="both" dir="ltr">
    <div class="common">Both</div>
</div>



#single, #both{
    width: 100px;
    height: 100px;
    overflow: auto;
    margin: 0 auto;
    border: 1px solid gray;
}


.common{
    height: 150px;
    width: 150px;
}

Is it possible to disable scrolling on a ViewPager

The answer of slayton works fine. If you want to stop swiping like a monkey you can override a OnPageChangeListener with

@Override public void onPageScrollStateChanged(final int state) { 
        switch (state) { 
            case ViewPager.SCROLL_STATE_SETTLING: 
                mPager.setPagingEnabled(false); 
                break; 
            case ViewPager.SCROLL_STATE_IDLE: 
                mPager.setPagingEnabled(true); 
                break; 
        } 
    }

So you can only swipe side by side

spring autowiring with unique beans: Spring expected single matching bean but found 2

If you have 2 beans of the same class autowired to one class you shoud use @Qualifier (Spring Autowiring @Qualifier example).

But it seems like your problem comes from incorrect Java Syntax.

Your object should start with lower case letter

SuggestionService suggestion;

Your setter should start with lower case as well and object name should be with Upper case

public void setSuggestion(final Suggestion suggestion) {
    this.suggestion = suggestion;
}

Check if a value is in an array or not with Excel VBA

This Question was asked here: VBA Arrays - Check strict (not approximative) match

Sub test()
    vars1 = Array("Examples")
    vars2 = Array("Example")
    If IsInArray(Range("A1").value, vars1) Then
        x = 1
    End If

    If IsInArray(Range("A1").value, vars2) Then
        x = 1
    End If
End Sub

Function IsInArray(stringToBeFound As String, arr As Variant) As Boolean
    IsInArray = Not IsError(Application.Match(stringToBeFound, arr, 0))
End Function

Understanding checked vs unchecked exceptions in Java

Just to point out that if you throw a checked exception in a code and the catch is few levels above, you need to declare the exception in the signature of each method between you and the catch. So, encapsulation is broken because all functions in the path of throw must know about details of that exception.

Can I force pip to reinstall the current version?

--force-reinstall

doesn't appear to force reinstall using python2.7 with pip-1.5

I've had to use

--no-deps --ignore-installed

error : expected unqualified-id before return in c++

Just for the sake of people who landed here for the same reason I did:

Don't use reserved keywords

I named a function in my class definition delete(), which is a reserved keyword and should not be used as a function name. Renaming it to deletion() (which also made sense semantically in my case) resolved the issue.

For a list of reserved keywords: http://en.cppreference.com/w/cpp/keyword

I quote: "Since they are used by the language, these keywords are not available for re-definition or overloading. "

How to vertically align elements in a div?

Wow, this problem is popular. It's based on a misunderstanding in the vertical-align property. This excellent article explains it:

Understanding vertical-align, or "How (Not) To Vertically Center Content" by Gavin Kistner.

“How to center in CSS” is a great web tool which helps to find the necessary CSS centering attributes for different situations.


In a nutshell (and to prevent link rot):

  • Inline elements (and only inline elements) can be vertically aligned in their context via vertical-align: middle. However, the “context” isn’t the whole parent container height, it’s the height of the text line they’re in. jsfiddle example
  • For block elements, vertical alignment is harder and strongly depends on the specific situation:
    • If the inner element can have a fixed height, you can make its position absolute and specify its height, margin-top and top position. jsfiddle example
    • If the centered element consists of a single line and its parent height is fixed you can simply set the container’s line-height to fill its height. This method is quite versatile in my experience. jsfiddle example
    • … there are more such special cases.

Running two projects at once in Visual Studio

Go to Solution properties ? Common Properties ? Startup Project and select Multiple startup projects.

Solution properties dialog

Node Sass couldn't find a binding for your current environment

For people that switched to nvm from system node, if you haven't removed the ~/.npm and ~/.node-gyp folder this problem can arise since perhaps the node version within ~/.node-gyp could be different.

In any case those folders should be removed.

WPF - add static items to a combo box

Here is the code from MSDN and the link - Article Link, which you should check out for more detail.

<ComboBox Text="Is not open">
    <ComboBoxItem Name="cbi1">Item1</ComboBoxItem>
    <ComboBoxItem Name="cbi2">Item2</ComboBoxItem>
    <ComboBoxItem Name="cbi3">Item3</ComboBoxItem>
</ComboBox>

How to return a value from pthread threads in C?

You are returning a reference to ret which is a variable on the stack.

Oracle get previous day records

Simple solution and understanding

To answer the question:

SELECT field,datetime_field 
FROM database
WHERE TO_CHAR(date_field, 'YYYYMMDD') = TO_CHAR(SYSDATE-1, 'YYYYMMDD');

Some explanation

If you have a field that is not in date format but want to compare using date i.e. field is considered as date but in number format e.g. 20190823 (YYYYMMDD)

SELECT * FROM YOUR_TABLE WHERE ID_DATE = TO_CHAR(SYSDATE-1, 'YYYYMMDD') 

If you have a field that is in date/timestamp format and you need to compare, Just change the format

SELECT TO_CHAR(SYSDATE-1, 'YYYY-MM-DD HH24:MI:SS')  FROM DUAL

IF you want to return it to date format

SELECT TO_DATE(TO_CHAR(SYSDATE-1, 'YYYY-MM-DD HH24:MI:SS'), 'YYYY-MM-DD HH24:MI:SS') AS NEW_DATE  FROM DUAL

Conclusion.

With this knowledge you can convert the filed you want to compare to a YYYYMMDD or YYYY-MM-DD or any year-month-date format then compare with the same sysdate format.

mysql error 1364 Field doesn't have a default values

Run mysql console:

mysql -u your_username -p

, select database:

USE your_database;

and run (also from mysql console):

SET GLOBAL sql_mode='';

That will turn off strict mode and mysql won't complain any more.

To make things clear: your database definition says "this field must have default value defined", and by doing steps from above you say to MySql "neah, just ignore it". So if you just want to do some quick fix locally this solution is ok. But generally you should investigate in your database definition and check if field really needs default value and if so set it. And if default value is not needed this requirement should be removed to have clean situation.

Better solution without exluding fields from Binding

You should not use your domain models in your views. ViewModels are the correct way to do it.

You need to map your domain model's necessary fields to viewmodel and then use this viewmodel in your controllers. This way you will have the necessery abstraction in your application.

If you never heard of viewmodels, take a look at this.

My C# application is returning 0xE0434352 to Windows Task Scheduler but it is not crashing

I was referencing a mapped drive and I found that the mapped drives are not always available to the user account that is running the scheduled task so I used \\IPADDRESS instead of MAPDRIVELETTER: and I am up and running.

Spring JSON request getting 406 (not Acceptable)

<dependency>
    <groupId>com.fasterxml.jackson.jaxrs</groupId>
    <artifactId>jackson-jaxrs-base</artifactId>
    <version>2.6.3</version>
</dependency>

How to edit a JavaScript alert box title?

No, it is not possible. You can use a custom javascript alert box.

Found a nice one using jQuery

jQuery Alert Dialogs (Alert, Confirm, & Prompt Replacements)

Check if a JavaScript string is a URL

If you can change the input type, I think this solution would be much easier:

You can simple use type="url" in your input and the check it with checkValidity() in js

E.g:

your.html

<input id="foo" type="url">

your.js

// The selector is JQuery, but the function is plain JS
$("#foo").on("keyup", function() {
    if (this.checkValidity()) {
        // The url is valid
    } else {
        // The url is invalid
    }
});

Does svn have a `revert-all` command?

There is a command

svn revert -R .

OR
you can use the --depth=infinity, which is actually same as above:

svn revert --depth=infinity 

svn revert is inherently dangerous, since its entire purpose is to throw away data—namely, your uncommitted changes. Once you've reverted, Subversion provides no way to get back those uncommitted changes

Is it possible to style a select box?

Simple solution is Warp your select box inside a div, and style the div matching your design. Set opacity:0 to select box, it will make the select box invisible. Insert a span tag with jQuery and change its value dynamically if user change drop down value. Total demonstration shown in this tutorial with code explanation. Hope it will solve your problem.

JQuery Code looks like similar to this.

 <script>
   $(document).ready(function(){
     $('.dropdown_menu').each(function(){
       var baseData = $(this).find("select option:selected").html();
       $(this).prepend("<span>" + baseData + "</span>");
     });

     $(".dropdown_menu select").change(function(e){
       var nodeOne = $(this).val();
       var currentNode = $(this).find("option[value='"+ nodeOne +"']").text();
       $(this).parents(".dropdown_menu").find("span").text(currentNode);
     });
   });
</script>

Unsigned values in C

Assign a int -1 to an unsigned: As -1 does not fit in the range [0...UINT_MAX], multiples of UINT_MAX+1 are added until the answer is in range. Evidently UINT_MAX is pow(2,32)-1 or 429496725 on OP's machine so a has the value of 4294967295.

    unsigned int a = -1;

The "%x", "%u" specifier expects a matching unsigned. Since these do not match, "If a conversion specification is invalid, the behavior is undefined. If any argument is not the correct type for the corresponding conversion specification, the behavior is undefined." C11 §7.21.6.1 9. The printf specifier does not change b.

    printf("%x\n", b);  // UB
    printf("%u\n", b);  // UB

The "%d" specifier expects a matching int. Since these do not match, more UB.

    printf("%d\n", a);  // UB

Given undefined behavior, the conclusions are not supported.


both cases, the bytes are the same (ffffffff).

Even with the same bit pattern, different types may have different values. ffffffff as an unsigned has the value of 4294967295. As an int, depending signed integer encoding, it has the value of -1, -2147483647 or TBD. As a float it may be a NAN.

what is unsigned word for?

unsigned stores a whole number in the range [0 ... UINT_MAX]. It never has a negative value. If code needs a non-negative number, use unsigned. If code needs a counting number that may be +, - or 0, use int.


Update: to avoid a compiler warning about assigning a signed int to unsigned, use the below. This is an unsigned 1u being negated - which is well defined as above. The effect is the same as a -1, but conveys to the compiler direct intentions.

unsigned int a = -1u;

Check if null Boolean is true results in exception

as your variable bool is pointing to a null, you will always get a NullPointerException, you need to initialize the variable first somewhere with a not null value, and then modify it.

Convert.ToDateTime: how to set format

DateTime doesn't have a format. the format only applies when you're turning a DateTime into a string, which happens implicitly you show the value on a form, web page, etc.

Look at where you're displaying the DateTime and set the format there (or amend your question if you need additional guidance).

Unsupported major.minor version 52.0 when rendering in Android Studio

Also, if issue appears while executing ./gradlew command, setting java home in gradle.properties file, solves this issue:

org.gradle.java.home=/usr/java/jdk1.8.0_45/

How to execute .sql file using powershell?

with 2008 Server 2008 and 2008 R2

Add-PSSnapin -Name SqlServerCmdletSnapin100, SqlServerProviderSnapin100

with 2012 and 2014

Push-Location
Import-Module -Name SQLPS -DisableNameChecking
Pop-Location

Post-increment and pre-increment within a 'for' loop produce same output

This is one of my favorite interview questions. I'll explain the answer first, and then tell you why I like the question.

Solution:

The answer is that both snippets print the numbers from 0 to 4, inclusive. This is because a for() loop is generally equivalent to a while() loop:

for (INITIALIZER; CONDITION; OPERATION) {
    do_stuff();
}

Can be written:

INITIALIZER;
while(CONDITION) {
    do_stuff();
    OPERATION;
}

You can see that the OPERATION is always done at the bottom of the loop. In this form, it should be clear that i++ and ++i will have the same effect: they'll both increment i and ignore the result. The new value of i is not tested until the next iteration begins, at the top of the loop.


Edit: Thanks to Jason for pointing out that this for() to while() equivalence does not hold if the loop contains control statements (such as continue) that would prevent OPERATION from being executed in a while() loop. OPERATION is always executed just before the next iteration of a for() loop.


Why it's a Good Interview Question

First of all, it takes only a minute or two if a candidate tells the the correct answer immediately, so we can move right on to the next question.

But surprisingly (to me), many candidates tell me the loop with the post-increment will print the numbers from 0 to 4, and the pre-increment loop will print 0 to 5, or 1 to 5. They usually explain the difference between pre- and post-incrementing correctly, but they misunderstand the mechanics of the for() loop.

In that case, I ask them to rewrite the loop using while(), and this really gives me a good idea of their thought processes. And that's why I ask the question in the first place: I want to know how they approach a problem, and how they proceed when I cast doubt on the way their world works.

At this point, most candidates realize their error and find the correct answer. But I had one who insisted his original answer was right, then changed the way he translated the for() to the while(). It made for a fascinating interview, but we didn't make an offer!

Hope that helps!

Complex numbers usage in python

The following example for complex numbers should be self explanatory including the error message at the end

>>> x=complex(1,2)
>>> print x
(1+2j)
>>> y=complex(3,4)
>>> print y
(3+4j)
>>> z=x+y
>>> print x
(1+2j)
>>> print z
(4+6j)
>>> z=x*y
>>> print z
(-5+10j)
>>> z=x/y
>>> print z
(0.44+0.08j)
>>> print x.conjugate()
(1-2j)
>>> print x.imag
2.0
>>> print x.real
1.0
>>> print x>y

Traceback (most recent call last):
  File "<pyshell#149>", line 1, in <module>
    print x>y
TypeError: no ordering relation is defined for complex numbers
>>> print x==y
False
>>> 

jQuery - adding elements into an array

var ids = [];

    $(document).ready(function($) {    
    $(".color_cell").bind('click', function() {
        alert('Test');

        ids.push(this.id);       
    });
});

ASP.NET MVC Razor render without encoding

You can also use the WriteLiteral method

ReactJS map through Object

Do you get an error when you try to map through the object keys, or does it throw something else.

Also note when you want to map through the keys you make sure to refer to the object keys correctly. Just like this:

{ Object.keys(subjects).map((item, i) => (
   <li className="travelcompany-input" key={i}>
     <span className="input-label">key: {i} Name: {subjects[item]}</span>
    </li>
))}

You need to use {subjects[item]} instead of {subjects[i]} because it refers to the keys of the object. If you look for subjects[i] you will get undefined.

"Keep Me Logged In" - the best approach

Security Notice: Basing the cookie off an MD5 hash of deterministic data is a bad idea; it's better to use a random token derived from a CSPRNG. See ircmaxell's answer to this question for a more secure approach.

Usually I do something like this:

  1. User logs in with 'keep me logged in'
  2. Create session
  3. Create a cookie called SOMETHING containing: md5(salt+username+ip+salt) and a cookie called somethingElse containing id
  4. Store cookie in database
  5. User does stuff and leaves ----
  6. User returns, check for somethingElse cookie, if it exists, get the old hash from the database for that user, check of the contents of cookie SOMETHING match with the hash from the database, which should also match with a newly calculated hash (for the ip) thus: cookieHash==databaseHash==md5(salt+username+ip+salt), if they do, goto 2, if they don't goto 1

Off course you can use different cookie names etc. also you can change the content of the cookie a bit, just make sure it isn't to easily created. You can for example also create a user_salt when the user is created and also put that in the cookie.

Also you could use sha1 instead of md5 (or pretty much any algorithm)

How to iterate over a TreeMap?

    //create TreeMap instance
    TreeMap treeMap = new TreeMap();

    //add key value pairs to TreeMap
    treeMap.put("1","One");
    treeMap.put("2","Two");
    treeMap.put("3","Three");

    /*
      get Collection of values contained in TreeMap using
      Collection values()        
    */
    Collection c = treeMap.values();

    //obtain an Iterator for Collection
    Iterator itr = c.iterator();

    //iterate through TreeMap values iterator
    while(itr.hasNext())
      System.out.println(itr.next());

or:

   for (Map.Entry<K,V> entry : treeMap.entrySet()) {
        V value = entry.getValue();
        K key = entry.getKey();
   }

or:

   // Use iterator to display the keys and associated values
   System.out.println("Map Values Before: ");
   Set keys = map.keySet();
   for (Iterator i = keys.iterator(); i.hasNext();) {
     Integer key = (Integer) i.next();
     String value = (String) map.get(key);
     System.out.println(key + " = " + value);
   }

How to use onSavedInstanceState example please

This is for extra information.

Imagine this scenario

  1. ActivityA launch ActivityB.
  2. ActivityB launch a new ActivityAPrime by

    Intent intent = new Intent(getApplicationContext(), ActivityA.class);
    startActivity(intent);
    
  3. ActivityAPrime has no relationship with ActivityA.
    In this case the Bundle in ActivityAPrime.onCreate() will be null.

If ActivityA and ActivityAPrime should be the same activity instead of different activities, ActivityB should call finish() than using startActivity().

How do I expand the output display to see more columns of a pandas DataFrame?

Set column max width using:

pd.set_option('max_colwidth', 800)

This particular statement sets max width to 800px, per column.

Name node is in safe mode. Not able to leave

Try this

sudo -u hdfs hdfs dfsadmin -safemode leave

check status of safemode

sudo -u hdfs hdfs dfsadmin -safemode get

If it is still in safemode ,then one of the reason would be not enough space in your node, you can check your node disk usage using :

df -h

if root partition is full, delete files or add space in your root partition and retry first step.

Android textview outline text

outline effect can be achieved using shadow in TextView:

    android:shadowColor="#000000"
    android:shadowDx="1.5"
    android:shadowDy="1.3"
    android:shadowRadius="1.6"
    android:text="CCC"
    android:textAllCaps="true"
    android:textColor="@android:color/white"

Trim whitespace from a String

I think that substr() throws an exception if str only contains the whitespace.

I would modify it to the following code:

string trim(string& str)
{
    size_t first = str.find_first_not_of(' ');
    if (first == std::string::npos)
        return "";
    size_t last = str.find_last_not_of(' ');
    return str.substr(first, (last-first+1));
}

How to see which flags -march=native will activate?

You can use the -Q --help=target options:

gcc -march=native -Q --help=target ...

The -v option may also be of use.

You can see the documentation on the --help option here.

How to get a path to the desktop for current user in C#?

string path = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);

bootstrap 4 responsive utilities visible / hidden xs sm lg not working

Screen Size Class

-

  1. Hidden on all .d-none

  2. Hidden only on xs .d-none .d-sm-block

  3. Hidden only on sm .d-sm-none .d-md-block

  4. Hidden only on md .d-md-none .d-lg-block

  5. Hidden only on lg .d-lg-none .d-xl-block

  6. Hidden only on xl .d-xl-none

  7. Visible on all .d-block

  8. Visible only on xs .d-block .d-sm-none

  9. Visible only on sm .d-none .d-sm-block .d-md-none

  10. Visible only on md .d-none .d-md-block .d-lg-none

  11. Visible only on lg .d-none .d-lg-block .d-xl-none

  12. Visible only on xl .d-none .d-xl-block

Refer this link http://getbootstrap.com/docs/4.0/utilities/display/#hiding-elements

4.5 link: https://getbootstrap.com/docs/4.5/utilities/display/#hiding-elements

How do I get the real .height() of a overflow: hidden or overflow: scroll div?

I have just cooked up another solution for this, where it's not longer necessary to use a -much to high- max-height value. It needs a few lines of javascript code to calculate the inner height of the collapsed DIV but after that, it's all CSS.

1) Fetching and setting height

Fetch the inner height of the collapsed element (using scrollHeight). My element has a class .section__accordeon__content and I actually run this in a forEach() loop to set the height for all panels, but you get the idea.

document.querySelectorAll( '.section__accordeon__content' ).style.cssText = "--accordeon-height: " + accordeonPanel.scrollHeight + "px";

2) Use the CSS variable to expand the active item

Next, use the CSS variable to set the max-height value when the item has an .active class.

.section__accordeon__content.active {
  max-height: var(--accordeon-height);
}

Final example

So the full example goes like this: first loop through all accordeon panels and store their scrollHeight values as CSS variables. Next use the CSS variable as the max-height value on the active/expanded/open state of the element.

Javascript:

document.querySelectorAll( '.section__accordeon__content' ).forEach(
  function( accordeonPanel ) {
    accordeonPanel.style.cssText = "--accordeon-height: " + accordeonPanel.scrollHeight + "px";
  }
);

CSS:

.section__accordeon__content {
  max-height: 0px;
  overflow: hidden;
  transition: all 425ms cubic-bezier(0.465, 0.183, 0.153, 0.946);
}

.section__accordeon__content.active {
  max-height: var(--accordeon-height);
}

And there you have it. A adaptive max-height animation using only CSS and a few lines of JavaScript code (no jQuery required).

Hope this helps someone in the future (or my future self for reference).

Python Flask, how to set content type

Try like this:

from flask import Response
@app.route('/ajax_ddl')
def ajax_ddl():
    xml = 'foo'
    return Response(xml, mimetype='text/xml')

The actual Content-Type is based on the mimetype parameter and the charset (defaults to UTF-8).

Response (and request) objects are documented here: http://werkzeug.pocoo.org/docs/wrappers/

How to stop an animation (cancel() does not work)

To stop animation you may set such objectAnimator that do nothing, e.g.

first when manual flipping there is animation left to right:

flipper.setInAnimation(leftIn);
flipper.setOutAnimation(rightOut);

then when switching to auto flipping there's no animation

flipper.setInAnimation(doNothing);
flipper.setOutAnimation(doNothing);

doNothing = ObjectAnimator.ofFloat(flipper, "x", 0f, 0f).setDuration(flipperSwipingDuration);

best way to preserve numpy arrays on disk

Another possibility to store numpy arrays efficiently is Bloscpack:

#!/usr/bin/python
import numpy as np
import bloscpack as bp
import time

n = 10000000

a = np.arange(n)
b = np.arange(n) * 10
c = np.arange(n) * -0.5
tsizeMB = sum(i.size*i.itemsize for i in (a,b,c)) / 2**20.

blosc_args = bp.DEFAULT_BLOSC_ARGS
blosc_args['clevel'] = 6
t = time.time()
bp.pack_ndarray_file(a, 'a.blp', blosc_args=blosc_args)
bp.pack_ndarray_file(b, 'b.blp', blosc_args=blosc_args)
bp.pack_ndarray_file(c, 'c.blp', blosc_args=blosc_args)
t1 = time.time() - t
print "store time = %.2f (%.2f MB/s)" % (t1, tsizeMB / t1)

t = time.time()
a1 = bp.unpack_ndarray_file('a.blp')
b1 = bp.unpack_ndarray_file('b.blp')
c1 = bp.unpack_ndarray_file('c.blp')
t1 = time.time() - t
print "loading time = %.2f (%.2f MB/s)" % (t1, tsizeMB / t1)

and the output for my laptop (a relatively old MacBook Air with a Core2 processor):

$ python store-blpk.py
store time = 0.19 (1216.45 MB/s)
loading time = 0.25 (898.08 MB/s)

that means that it can store really fast, i.e. the bottleneck is typically the disk. However, as the compression ratios are pretty good here, the effective speed is multiplied by the compression ratios. Here are the sizes for these 76 MB arrays:

$ ll -h *.blp
-rw-r--r--  1 faltet  staff   921K Mar  6 13:50 a.blp
-rw-r--r--  1 faltet  staff   2.2M Mar  6 13:50 b.blp
-rw-r--r--  1 faltet  staff   1.4M Mar  6 13:50 c.blp

Please note that the use of the Blosc compressor is fundamental for achieving this. The same script but using 'clevel' = 0 (i.e. disabling compression):

$ python bench/store-blpk.py
store time = 3.36 (68.04 MB/s)
loading time = 2.61 (87.80 MB/s)

is clearly bottlenecked by the disk performance.

C-like structures in Python

Personally, I like this variant too. It extends @dF's answer.

class struct:
    def __init__(self, *sequential, **named):
        fields = dict(zip(sequential, [None]*len(sequential)), **named)
        self.__dict__.update(fields)
    def __repr__(self):
        return str(self.__dict__)

It supports two modes of initialization (that can be blended):

# Struct with field1, field2, field3 that are initialized to None.
mystruct1 = struct("field1", "field2", "field3") 
# Struct with field1, field2, field3 that are initialized according to arguments.
mystruct2 = struct(field1=1, field2=2, field3=3)

Also, it prints nicer:

print(mystruct2)
# Prints: {'field3': 3, 'field1': 1, 'field2': 2}

Numpy: Creating a complex array from 2 real ones?

There's of course the rather obvious:

Data[...,0] + 1j * Data[...,1]

Adding blank spaces to layout

Agree with all the answers......also,

    <TextView android:text=""
              android:layout_width="match_parent"
              android:layout_height="30dp"
              android:layout_weight="2" />

should work :) I am just messing with others as TextView is my favourite (waste of memory though!)

How to get a Fragment to remove itself, i.e. its equivalent of finish()?

See if your needs are met by a DialogFragment. DialogFragment has a dismiss() method. Much cleaner in my opinion.

How to convert int to date in SQL Server 2008

Reading through this helps solve a similar problem. The data is in decimal datatype - [DOB] [decimal](8, 0) NOT NULL - eg - 19700109. I want to get at the month. The solution is to combine SUBSTRING with CONVERT to VARCHAR.

    SELECT [NUM]
       ,SUBSTRING(CONVERT(VARCHAR, DOB),5,2) AS mob
    FROM [Dbname].[dbo].[Tablename] 

Execute php file from another php

Sounds like you're trying to execute the PHP code directly in your shell. Your shell doesn't speak PHP, so it interprets your PHP code as though it's in your shell's native language, as though you had literally run <?php at the command line.

Shell scripts usually start with a "shebang" line that tells the shell what program to use to interpret the file. Begin your file like this:

#!/usr/bin/env php
<?php
//Connection
function connection () {

Besides that, the string you're passing to exec doesn't make any sense. It starts with a slash all by itself, it uses too many periods in the path, and it has a stray right parenthesis.

Copy the contents of the command string and paste them at your command line. If it doesn't run there, then exec probably won't be able to run it, either.

Another option is to change the command you execute. Instead of running the script directly, run php and pass your script as an argument. Then you shouldn't need the shebang line.

exec('php name.php');

How to reset AUTO_INCREMENT in MySQL?

You can also use the syntax TRUNCATE table like this : TRUNCATE TABLE table_name

BEWARE!! TRUNCATE TABLE your_table will delete everything in your your_table!!

Setting TIME_WAIT TCP

A TCP connection is specified by the tuple (source IP, source port, destination IP, destination port).

The reason why there is a TIME_WAIT state following session shutdown is because there may still be live packets out in the network on their way to you (or from you which may solicit a response of some sort). If you were to re-create that same tuple and one of those packets showed up, it would be treated as a valid packet for your connection (and probably cause an error due to sequencing).

So the TIME_WAIT time is generally set to double the packets maximum age. This value is the maximum age your packets will be allowed to get to before the network discards them.

That guarantees that, before you're allowed to create a connection with the same tuple, all the packets belonging to previous incarnations of that tuple will be dead.

That generally dictates the minimum value you should use. The maximum packet age is dictated by network properties, an example being that satellite lifetimes are higher than LAN lifetimes since the packets have much further to go.

How to get changes from another branch

For other people coming upon this post on google. There are 2 options, either merging or rebasing your branch. Both works differently, but have similar outcomes.

The accepted answer is a rebase. This will take all the commits done to our-team and then apply the commits done to featurex, prompting you to merge them as needed.

One bit caveat of rebasing is that you lose/rewrite your branch history, essentially telling git that your branch did not began at commit 123abc but at commit 456cde. This will cause problems for other people working on the branch, and some remote tools will complain about it. If you are sure about what you are doing though, that's what the --force flag is for.

What other posters are suggesting is a merge. This will take the featurex branch, with whatever state it has and try to merge it with the current state of our-team, prompting you to do one, big, merge commit and fix all the merge errors before pushing to our-team. The difference is that you are applying your featurex commits before the our-team new commits and then fixing the differences. You also do not rewrite history, instead adding one commit to it instead of rewriting those that came before.

Both options are valid and can work in tandem. What is usually (by that I mean, if you are using widespread tools and methodology such as git-flow) done for a feature branch is to merge it into the main branch, often going through a merge-request, and solve all the conflicts that arise into one (or multiple) merge commits.

Rebasing is an interesting option, that may help you fix your branch before eventually going through a merge, and ease the pain of having to do one big merge commit.

Deep cloning objects

Whereas one approach is to implement the ICloneable interface (described here, so I won't regurgitate), here's a nice deep clone object copier I found on The Code Project a while ago and incorporated it into our code. As mentioned elsewhere, it requires your objects to be serializable.

using System;
using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;

/// <summary>
/// Reference Article http://www.codeproject.com/KB/tips/SerializedObjectCloner.aspx
/// Provides a method for performing a deep copy of an object.
/// Binary Serialization is used to perform the copy.
/// </summary>
public static class ObjectCopier
{
    /// <summary>
    /// Perform a deep copy of the object via serialization.
    /// </summary>
    /// <typeparam name="T">The type of object being copied.</typeparam>
    /// <param name="source">The object instance to copy.</param>
    /// <returns>A deep copy of the object.</returns>
    public static T Clone<T>(T source)
    {
        if (!typeof(T).IsSerializable)
        {
            throw new ArgumentException("The type must be serializable.", nameof(source));
        }

        // Don't serialize a null object, simply return the default for that object
        if (ReferenceEquals(self, null)) return default;

        using var Stream stream = new MemoryStream();
        IFormatter formatter = new BinaryFormatter();
        formatter.Serialize(stream, source);
        stream.Seek(0, SeekOrigin.Begin);
        return (T)formatter.Deserialize(stream);
    }
}

The idea is that it serializes your object and then deserializes it into a fresh object. The benefit is that you don't have to concern yourself about cloning everything when an object gets too complex.

In case of you prefer to use the new extension methods of C# 3.0, change the method to have the following signature:

public static T Clone<T>(this T source)
{
   // ...
}

Now the method call simply becomes objectBeingCloned.Clone();.

EDIT (January 10 2015) Thought I'd revisit this, to mention I recently started using (Newtonsoft) Json to do this, it should be lighter, and avoids the overhead of [Serializable] tags. (NB @atconway has pointed out in the comments that private members are not cloned using the JSON method)

/// <summary>
/// Perform a deep Copy of the object, using Json as a serialization method. NOTE: Private members are not cloned using this method.
/// </summary>
/// <typeparam name="T">The type of object being copied.</typeparam>
/// <param name="source">The object instance to copy.</param>
/// <returns>The copied object.</returns>
public static T CloneJson<T>(this T source)
{            
    // Don't serialize a null object, simply return the default for that object
    if (ReferenceEquals(self, null)) return default;

    // initialize inner objects individually
    // for example in default constructor some list property initialized with some values,
    // but in 'source' these items are cleaned -
    // without ObjectCreationHandling.Replace default constructor values will be added to result
    var deserializeSettings = new JsonSerializerSettings {ObjectCreationHandling = ObjectCreationHandling.Replace};

    return JsonConvert.DeserializeObject<T>(JsonConvert.SerializeObject(source), deserializeSettings);
}

A fatal error occurred while creating a TLS client credential. The internal error state is 10013

I found this here: https://port135.com/schannel-the-internal-error-state-is-10013-solved/

"Correct file permissions Correct the permissions on the c:\ProgramData\Microsoft\Crypto\RSA\MachineKeys folder:

Everyone Access: Special Applies to 'This folder only' Network Service Access: Read & Execute Applies to 'This folder, subfolders and files' Administrators Access: Full Control Applies to 'This folder, subfolder and files' System Access: Full control Applies to 'This folder, subfolder and Files' IUSR Access: Full Control Applies to 'This folder, subfolder and files' The internal error state is 10013 After these changes, restart the server. The 10013 errors should disappear."

How to Exit a Method without Exiting the Program?

If the function is a void, ending the function will return. Otherwise, you need to do an explicit return someValue. As Mark mentioned, you can also throw an exception. What's the context of your question? Do you have a larger code sample with which to show you some ways to exit the function?

Tri-state Check box in HTML?

Refering to @BoltClock answer, here is my solution for a more complex recursive method:

http://jsfiddle.net/gx7so2tq/2/

It might not be the most pretty solution but it works fine for me and is quite flexible.

I use two data objects defining the container:

data-select-all="chapter1"

and the elements itself:

data-select-some="chapter1"

Both having the same value. The combination of both data-objects within one checkbox allows sublevels, which are scanned recursively. Therefore two "helper" functions are needed to prevent the change-trigger.

Should I use Vagrant or Docker for creating an isolated environment?

Definitely Docker for the win!

As you may know Vagrant is for virtual machine management whereas Docker is for software containers management. If you are not aware of the difference, here is: A software container can share the same machine and kernel with other software containers. Using containers you save money because you don't waste resources on multiple operating systems (kernels), you can pack more software per server keeping a good degree of isolation.

Of course is a new discipline to care with its own pitfals and challenges.

Go for Docker Swarm if your requirements cross the single machine resources limit.

Execute Immediate within a stored procedure keeps giving insufficient priviliges error

you could use "AUTHID CURRENT_USER" in body of your procedure definition for your requirements.

Appending a vector to a vector

While saying "the compiler can reserve", why rely on it? And what about automatic detection of move semantics? And what about all that repeating of the container name with the begins and ends?

Wouldn't you want something, you know, simpler?

(Scroll down to main for the punchline)

#include <type_traits>
#include <vector>
#include <iterator>
#include <iostream>

template<typename C,typename=void> struct can_reserve: std::false_type {};

template<typename T, typename A>
struct can_reserve<std::vector<T,A>,void>:
    std::true_type
{};

template<int n> struct secret_enum { enum class type {}; };
template<int n>
using SecretEnum = typename secret_enum<n>::type;

template<bool b, int override_num=1>
using EnableFuncIf = typename std::enable_if< b, SecretEnum<override_num> >::type;
template<bool b, int override_num=1>
using DisableFuncIf = EnableFuncIf< !b, -override_num >;

template<typename C, EnableFuncIf< can_reserve<C>::value >... >
void try_reserve( C& c, std::size_t n ) {
  c.reserve(n);
}
template<typename C, DisableFuncIf< can_reserve<C>::value >... >
void try_reserve( C& c, std::size_t ) { } // do nothing

template<typename C,typename=void>
struct has_size_method:std::false_type {};
template<typename C>
struct has_size_method<C, typename std::enable_if<std::is_same<
  decltype( std::declval<C>().size() ),
  decltype( std::declval<C>().size() )
>::value>::type>:std::true_type {};

namespace adl_aux {
  using std::begin; using std::end;
  template<typename C>
  auto adl_begin(C&&c)->decltype( begin(std::forward<C>(c)) );
  template<typename C>
  auto adl_end(C&&c)->decltype( end(std::forward<C>(c)) );
}
template<typename C>
struct iterable_traits {
    typedef decltype( adl_aux::adl_begin(std::declval<C&>()) ) iterator;
    typedef decltype( adl_aux::adl_begin(std::declval<C const&>()) ) const_iterator;
};
template<typename C> using Iterator = typename iterable_traits<C>::iterator;
template<typename C> using ConstIterator = typename iterable_traits<C>::const_iterator;
template<typename I> using IteratorCategory = typename std::iterator_traits<I>::iterator_category;

template<typename C, EnableFuncIf< has_size_method<C>::value, 1>... >
std::size_t size_at_least( C&& c ) {
    return c.size();
}

template<typename C, EnableFuncIf< !has_size_method<C>::value &&
  std::is_base_of< std::random_access_iterator_tag, IteratorCategory<Iterator<C>> >::value, 2>... >
std::size_t size_at_least( C&& c ) {
    using std::begin; using std::end;
  return end(c)-begin(c);
};
template<typename C, EnableFuncIf< !has_size_method<C>::value &&
  !std::is_base_of< std::random_access_iterator_tag, IteratorCategory<Iterator<C>> >::value, 3>... >
std::size_t size_at_least( C&& c ) {
  return 0;
};

template < typename It >
auto try_make_move_iterator(It i, std::true_type)
-> decltype(make_move_iterator(i))
{
    return make_move_iterator(i);
}
template < typename It >
It try_make_move_iterator(It i, ...)
{
    return i;
}


#include <iostream>
template<typename C1, typename C2>
C1&& append_containers( C1&& c1, C2&& c2 )
{
  using std::begin; using std::end;
  try_reserve( c1, size_at_least(c1) + size_at_least(c2) );

  using is_rvref = std::is_rvalue_reference<C2&&>;
  c1.insert( end(c1),
             try_make_move_iterator(begin(c2), is_rvref{}),
             try_make_move_iterator(end(c2), is_rvref{}) );

  return std::forward<C1>(c1);
}

struct append_infix_op {} append;
template<typename LHS>
struct append_on_right_op {
  LHS lhs;
  template<typename RHS>
  LHS&& operator=( RHS&& rhs ) {
    return append_containers( std::forward<LHS>(lhs), std::forward<RHS>(rhs) );
  }
};

template<typename LHS>
append_on_right_op<LHS> operator+( LHS&& lhs, append_infix_op ) {
  return { std::forward<LHS>(lhs) };
}
template<typename LHS,typename RHS>
typename std::remove_reference<LHS>::type operator+( append_on_right_op<LHS>&& lhs, RHS&& rhs ) {
  typename std::decay<LHS>::type retval = std::forward<LHS>(lhs.lhs);
  return append_containers( std::move(retval), std::forward<RHS>(rhs) );
}

template<typename C>
void print_container( C&& c ) {
  for( auto&& x:c )
    std::cout << x << ",";
  std::cout << "\n";
};

int main() {
  std::vector<int> a = {0,1,2};
  std::vector<int> b = {3,4,5};
  print_container(a);
  print_container(b);
  a +append= b;
  const int arr[] = {6,7,8};
  a +append= arr;
  print_container(a);
  print_container(b);
  std::vector<double> d = ( std::vector<double>{-3.14, -2, -1} +append= a );
  print_container(d);
  std::vector<double> c = std::move(d) +append+ a;
  print_container(c);
  print_container(d);
  std::vector<double> e = c +append+ std::move(a);
  print_container(e);
  print_container(a);
}

hehe.

Now with move-data-from-rhs, append-array-to-container, append forward_list-to-container, move-container-from-lhs, thanks to @DyP's help.

Note that the above does not compile in clang thanks to the EnableFunctionIf<>... technique. In clang this workaround works.

How do I search for names with apostrophe in SQL Server?

That's:

SELECT * FROM Header 
WHERE (userID LIKE '%''%')

How to change the datetime format in pandas

Below code changes to 'datetime' type and also formats in the given format string. Works well!

df['DOB']=pd.to_datetime(df['DOB'].dt.strftime('%m/%d/%Y'))

What method in the String class returns only the first N characters?

I added this in my project just because where I'm using it is a high chance of it being used in loops, in a project hosted online hence I didn't want any crashes if I could manage it. The length fits a column I have. It's C#7

Just a one line:

 public static string SubStringN(this string Message, int Len = 499) => !String.IsNullOrEmpty(Message) ? (Message.Length >= Len ? Message.Substring(0, Len) : Message) : "";

Split a List into smaller lists of N size

How about this one? The idea was to use only one loop. And, who knows, maybe you're using only IList implementations thorough your code and you don't want to cast to List.

private IEnumerable<IList<T>> SplitList<T>(IList<T> list, int totalChunks)
{
    IList<T> auxList = new List<T>();
    int totalItems = list.Count();

    if (totalChunks <= 0)
    {
        yield return auxList;
    }
    else 
    {
        for (int i = 0; i < totalItems; i++)
        {               
            auxList.Add(list[i]);           

            if ((i + 1) % totalChunks == 0)
            {
                yield return auxList;
                auxList = new List<T>();                
            }

            else if (i == totalItems - 1)
            {
                yield return auxList;
            }
        }
    }   
}

"Gradle Version 2.10 is required." Error

What worked for me on Mint 17.03 which is base off Ubuntu 14.04

sudo add-apt-repository ppa:cwchien/gradle sudo apt-get update sudo apt-get install gradle

Reopen Android Studio. Go to Run/Debug Configuration and there should be an icon saying you need to Update gradle. Just click it.

Convert date to UTC using moment.js

As of : moment.js version 2.24.0

let's say you have a local date input, this is the proper way to convert your dateTime or Time input to UTC :

var utcStart = new moment("09:00", "HH:mm").utc();

or in case you specify a date

var utcStart = new moment("2019-06-24T09:00", "YYYY-MM-DDTHH:mm").utc();

As you can see the result output will be returned in UTC :

//You can call the format() that will return your UTC date in a string 
 utcStart.format(); 
//Result : 2019-06-24T13:00:00 

But if you do this as below, it will not convert to UTC :

var myTime = new moment.utc("09:00", "HH:mm"); 

You're only setting your input to utc time, it's as if your mentioning that myTime is in UTC, ....the output will be 9:00

CSS smooth bounce animation

In case you're already using the transform property for positioning your element (as I currently am), you can also animate the top margin:

.ball {
  animation: bounce 1s infinite alternate;
  -webkit-animation: bounce 1s infinite alternate;
}

@keyframes bounce {
  from {
    margin-top: 0;
  }
  to {
    margin-top: -15px;
  }
}

jQuery.active function

For anyone trying to use jQuery.active with JSONP requests (like I was) you'll need enable it with this:

jQuery.ajaxPrefilter(function( options ) {
    options.global = true;
});

Keep in mind that you'll need a timeout on your JSONP request to catch failures.

Capitalize or change case of an NSString in Objective-C

Here ya go:

viewNoteDateMonth.text  = [[displayDate objectAtIndex:2] uppercaseString];

Btw:
"april" is lowercase ? [NSString lowercaseString]
"APRIL" is UPPERCASE ? [NSString uppercaseString]
"April May" is Capitalized/Word Caps ? [NSString capitalizedString]
"April may" is Sentence caps ? (method missing; see workaround below)

Hence what you want is called "uppercase", not "capitalized". ;)

As for "Sentence Caps" one has to keep in mind that usually "Sentence" means "entire string". If you wish for real sentences use the second method, below, otherwise the first:

@interface NSString ()

- (NSString *)sentenceCapitalizedString; // sentence == entire string
- (NSString *)realSentenceCapitalizedString; // sentence == real sentences

@end

@implementation NSString

- (NSString *)sentenceCapitalizedString {
    if (![self length]) {
        return [NSString string];
    }
    NSString *uppercase = [[self substringToIndex:1] uppercaseString];
    NSString *lowercase = [[self substringFromIndex:1] lowercaseString];
    return [uppercase stringByAppendingString:lowercase];
}

- (NSString *)realSentenceCapitalizedString {
    __block NSMutableString *mutableSelf = [NSMutableString stringWithString:self];
    [self enumerateSubstringsInRange:NSMakeRange(0, [self length])
                             options:NSStringEnumerationBySentences
                          usingBlock:^(NSString *sentence, NSRange sentenceRange, NSRange enclosingRange, BOOL *stop) {
        [mutableSelf replaceCharactersInRange:sentenceRange withString:[sentence sentenceCapitalizedString]];
    }];
    return [NSString stringWithString:mutableSelf]; // or just return mutableSelf.
}

@end

Django ManyToMany filter()

another way to do this is by going through the intermediate table. I'd express this within the Django ORM like this:

UserZone = User.zones.through

# for a single zone
users_in_zone = User.objects.filter(
  id__in=UserZone.objects.filter(zone=zone1).values('user'))

# for multiple zones
users_in_zones = User.objects.filter(
  id__in=UserZone.objects.filter(zone__in=[zone1, zone2, zone3]).values('user'))

it would be nice if it didn't need the .values('user') specified, but Django (version 3.0.7) seems to need it.

the above code will end up generating SQL that looks something like:

SELECT * FROM users WHERE id IN (SELECT user_id FROM userzones WHERE zone_id IN (1,2,3))

which is nice because it doesn't have any intermediate joins that could cause duplicate users to be returned

In Unix, how do you remove everything in the current directory and below it?

Will delete all files/directories below the current one.

find -mindepth 1 -delete

If you want to do the same with another directory whose name you have, you can just name that

find <name-of-directory> -mindepth 1 -delete

If you want to remove not only the sub-directories and files of it, but also the directory itself, omit -mindepth 1. Do it without the -delete to get a list of the things that will be removed.

How to add percent sign to NSString

uese following code.

 NSString *searchText = @"Bhupi"
 NSString *formatedSearchText = [NSString stringWithFormat:@"%%%@%%",searchText];

will output: %Bhupi%

How to remove blank lines from a Unix file

You can sed's -i option to edit in-place without using temporary file:

 sed -i '/^$/d' file

Android ClassNotFoundException: Didn't find class on path

For those of you who are having this issue on Android Studio, I had the same problem after a merge and for some reason it even persisted after clean and invalidate cash/restart operations which was driving me crazy.

Turns out, it can be fixed by running gradle build once from command line. Simply run the following n the project directory:

./gradlew assemble clean
./gradlew assemble

I hope it'd save someone the time waste and frustration I had to go through.

Regex allow digits and a single dot

\d*\.\d*

Explanation:

\d* - any number of digits

\. - a dot

\d* - more digits.

This will match 123.456, .123, 123., but not 123

If you want the dot to be optional, in most languages (don't know about jquery) you can use

\d*\.?\d*

How to align linearlayout to vertical center?

use RelativeLayout inside LinearLayout

example:

<LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerVertical="true"
                android:text="Status"/>
        </RelativeLayout>
</LinearLayout>

Calling pylab.savefig without display in ipython

This is a matplotlib question, and you can get around this by using a backend that doesn't display to the user, e.g. 'Agg':

import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt

plt.plot([1,2,3])
plt.savefig('/tmp/test.png')

EDIT: If you don't want to lose the ability to display plots, turn off Interactive Mode, and only call plt.show() when you are ready to display the plots:

import matplotlib.pyplot as plt

# Turn interactive plotting off
plt.ioff()

# Create a new figure, plot into it, then close it so it never gets displayed
fig = plt.figure()
plt.plot([1,2,3])
plt.savefig('/tmp/test0.png')
plt.close(fig)

# Create a new figure, plot into it, then don't close it so it does get displayed
plt.figure()
plt.plot([1,3,2])
plt.savefig('/tmp/test1.png')

# Display all "open" (non-closed) figures
plt.show()

Delete entire row if cell contains the string X

I'd like to add to @MBK's answer. Although I found @MBK's answer to be very helpful in solving a similar problem, it'd be better if @MBK included a screenshot of how to filter a particular column.enter image description here

When using Spring Security, what is the proper way to obtain current username (i.e. SecurityContext) information in a bean?

For the last Spring MVC app I wrote, I didn't inject the SecurityContext holder, but I did have a base controller that I had two utility methods related to this ... isAuthenticated() & getUsername(). Internally they do the static method call you described.

At least then it's only in once place if you need to later refactor.

Why am I getting "Thread was being aborted" in ASP.NET?

This problem occurs in the Response.Redirect and Server.Transfer methods, because both methods call Response.End internally.

The solution for this problem is as follows.

For Server.Transfer, use the Server.Execute method instead.

Visit this link for download an example.

Simple JavaScript Checkbox Validation

You could use:

 if(!this.form.checkbox.checked)
{
    alert('You must agree to the terms first.');
    return false;
}

(demo page).

<input type="checkbox" name="checkbox" value="check"  />
<input type="submit" name="email_submit" value="submit" onclick="if(!this.form.checkbox.checked){alert('You must agree to the terms first.');return false}"  />
  • Returning false from an inline event handler will prevent the default action from taking place (in this case, submitting the form).
  • ! is the Boolean NOT operator.
  • this is the submit button because it is the element the event handler is attached to.
  • .form is the form the submit button is in.
  • .checkbox is the control named "checkbox" in that form.
  • .checked is true if the checkbox is checked and false if the checkbox is unchecked.

jquery: change the URL address without redirecting?

NOTE: history.pushState() is now supported - see other answers.

You cannot change the whole url without redirecting, what you can do instead is change the hash.

The hash is the part of the url that goes after the # symbol. That was initially intended to direct you (locally) to sections of your HTML document, but you can read and modify it through javascript to use it somewhat like a global variable.


If applied well, this technique is useful in two ways:

  1. the browser history will remember each different step you took (since the url+hash changed)
  2. you can have an address which links not only to a particular html document, but also gives your javascript a clue about what to do. That means you end up pointing to a state inside your web app.

To change the hash you can do:

document.location.hash = "show_picture";

To watch for hash changes you have to do something like:

window.onhashchange = function(){
    var what_to_do = document.location.hash;    
    if (what_to_do=="#show_picture")
        show_picture();
}

Of course the hash is just a string, so you can do pretty much what you like with it. For example you can put a whole object there if you use JSON to stringify it.

There are very good JQuery libraries to do advanced things with that.

How do I get the opposite (negation) of a Boolean in Python?

The accepted answer here is the most correct for the given scenario.

It made me wonder though about simply inverting a boolean value in general. It turns out the accepted solution here works as one liner, and there's another one-liner that works as well. Assuming you have a variable "n" that you know is a boolean, the easiest ways to invert it are:

n = n is False

which was my original solution, and then the accepted answer from this question:

n = not n

The latter IS more clear, but I wondered about performance and hucked it through timeit - and it turns out at n = not n is also the FASTER way to invert the boolean value.

adb shell su works but adb root does not

I have a rooted Samsung Galaxy Trend Plus (GT-S7580).

Running 'adb root' gives me the same 'adbd cannot run as root in production builds' error.

For devices that have Developer Options -> Root access, choose "ADB only" to provide adb root access to the device (as suggested by NgaNguyenDuy).

Then try to run the command as per the solution at Launch a script as root through ADB. In my case, I just wanted to run the 'netcfg rndis0 dhcp' command, and I did it this way:

adb shell "su -c netcfg rndis0 dhcp"

Please check whether you are making any mistakes while running it this way.

If it still does not work, check whether you rooted the device correctly. If still no luck, try installing a custom ROM such as Cyanogen Mod in order for 'adb root' to work.

Generating Random Number In Each Row In Oracle Query

Something like?

select t.*, round(dbms_random.value() * 8) + 1 from foo t;

Edit: David has pointed out this gives uneven distribution for 1 and 9.

As he points out, the following gives a better distribution:

select t.*, floor(dbms_random.value(1, 10)) from foo t;

How do I wrap text in a span?

You should use white-space with display table

Example:
    legend {
        display:table; /* Enable line-wrapping in IE8+ */
        white-space:normal; /* Enable line-wrapping in old versions of some other browsers */
    }

is not JSON serializable

class CountryListView(ListView):
     model = Country

    def render_to_response(self, context, **response_kwargs):

         return HttpResponse(json.dumps(list(self.get_queryset().values_list('code', flat=True))),mimetype="application/json") 

fixed the problem

also mimetype is important.

How to use HTTP.GET in AngularJS correctly? In specific, for an external API call?

No need to promise with $http, i use it just with two returns :

 myApp.service('dataService', function($http) {
   this.getData = function() {
      return $http({
          method: 'GET',
          url: 'https://www.example.com/api/v1/page',
          params: 'limit=10, sort_by=created:desc',
          headers: {'Authorization': 'Token token=xxxxYYYYZzzz'}
      }).success(function(data){
        return data;
      }).error(function(){
         alert("error");
         return null ;
      });
   }
 });

In controller

 myApp.controller('AngularJSCtrl', function($scope, dataService) {
     $scope.data = null;
     dataService.getData().then(function(response) {
         $scope.data = response;
     });
 }); 

one line if statement in php

use the ternary operator ?:

change this

<?php if ($requestVars->_name == '') echo $redText; ?>

with

<?php echo ($requestVars->_name == '') ? $redText : ''; ?>

In short

// (Condition)?(thing's to do if condition true):(thing's to do if condition false);

Getting visitors country from their IP

Try

  <?php
  //gives you the IP address of the visitors
  if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
      $ip = $_SERVER['HTTP_CLIENT_IP'];}
  else if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
      $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
  } else {
      $ip = $_SERVER['REMOTE_ADDR'];
  }

  //return the country code
  $url = "http://api.wipmania.com/$ip";
  $country = file_get_contents($url);
  echo $country;

  ?>

"This operation requires IIS integrated pipeline mode."

Your Application Pool is in classic mode but your Application need integrated mode to fire. change it to Integrated Mode:

  1. Open IIS Manager

  2. Application Pool

  3. Select pool that your app are run in it

  4. In right panel select Basic Setting

  5. Manage Pipeline Mode change to Integrated

PHP: How to get referrer URL?

$_SERVER['HTTP_REFERER'] will give you the referrer page's URL if there exists any. If users use a bookmark or directly visit your site by manually typing in the URL, http_referer will be empty. Also if the users are posting to your page programatically (CURL) then they're not obliged to set the http_referer as well. You're missing all _, is that a typo?

Return list of items in list greater than some value

You can use a list comprehension to filter it:

j2 = [i for i in j if i >= 5]

If you actually want it sorted like your example was, you can use sorted:

j2 = sorted(i for i in j if i >= 5)

or call sort on the final list:

j2 = [i for i in j if i >= 5]
j2.sort()

Remove all multiple spaces in Javascript and replace with single space

you all forget about quantifier n{X,} http://www.w3schools.com/jsref/jsref_regexp_nxcomma.asp

here best solution

str = str.replace(/\s{2,}/g, ' ');

How to extract text from an existing docx file using python-docx

you can try this also

from docx import Document

document = Document('demo.docx')
for para in document.paragraphs:
    print(para.text)

How to create a HTML Table from a PHP array?

This is one of de best, simplest and most efficient ways to do it. You can convert arrays to tables with any number of columns or rows. It takes the array keys as table header. No need of array_map.

function array_to_table($matriz) 
{   
   echo "<table>";

   // Table header
        foreach ($matriz[0] as $clave=>$fila) {
            echo "<th>".$clave."</th>";
        }

    // Table body
       foreach ($matriz as $fila) {
           echo "<tr>";
           foreach ($fila as $elemento) {
                 echo "<td>".$elemento."</td>";
           } 
          echo "</tr>";
       } 
   echo "</table>";}

Getting value of HTML text input

Yes, you can use jQuery to make this done, the idea is

Use a hidden value in your form, and copy the value from external text box to this hidden value just before submitting the form.

<form name="input" action="handle_email.php" method="post">
  <input type="hidden" name="email" id="email" />
  <input type="submit" value="Submit" />
</form> 

<script>
   $("form").submit(function() {
     var emailFromOtherTextBox = $("#email_textbox").val();
     $("#email").val(emailFromOtherTextBox ); 
     return true;
  });
</script>

also see http://api.jquery.com/submit/

Adding a custom header to HTTP request using angular.js

I took what you had, and added another X-Testing header

var config = {headers:  {
        'Authorization': 'Basic d2VudHdvcnRobWFuOkNoYW5nZV9tZQ==',
        'Accept': 'application/json;odata=verbose',
        "X-Testing" : "testing"
    }
};

$http.get("/test", config);

And in the Chrome network tab, I see them being sent.

GET /test HTTP/1.1
Host: localhost:3000
Connection: keep-alive
Accept: application/json;odata=verbose
X-Requested-With: XMLHttpRequest
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.22 (KHTML, like Gecko) Chrome/25.0.1364.172 Safari/537.22
Authorization: Basic d2VudHdvcnRobWFuOkNoYW5nZV9tZQ==
X-Testing: testing
Referer: http://localhost:3000/
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3

Are you not seeing them from the browser, or on the server? Try the browser tooling or a debug proxy and see what is being sent out.

How do I pull my project from github?

There are few steps to be followed (For Windows)

  1. Open Git Bash and generate ssh key Paste the text below, substituting in your GitHub email address.

    ssh-keygen -t rsa -b 4096 -C "[email protected]"

    This creates a new ssh key, using the provided email as a label.

    Generating public/private rsa key pair.

    When you're prompted to "Enter a file in which to save the key," press Enter. This accepts the default file location.

    Enter a file in which to save the key (/c/Users/you/.ssh/id_rsa):[Press enter]

    At the prompt, type a secure passphrase. For more information, see "Working with SSH key passphrases".

    Enter passphrase (empty for no passphrase): [Type a passphrase] Enter same passphrase again: [Type passphrase again]

  2. Add the key to SSH Agent

    Type the following in Git Bash (99999 is just an example) to see agent is up and running. eval $(ssh-agent -s) Agent pid 99999

    then type this.

    ssh-add ~/.ssh/id_rsa

    then Copy the SSH key to your clipboard using this command

    clip < ~/.ssh/id_rsa.pub

  3. Add the SSH Key to the Git Account

    In GitHib site, click on the image on top right corner, and select settings. In the subsequent page, click SSH and GPG keys option. This will open up the SSH key page. Click on the New SSH key. In the "Title" field, add a descriptive label for the new key. Paste your key into the "Key" field.

  4. Clone the Repository

    Open VS Code (or any IDE/CLI which has command prompt etc.). Go to the directory in which you want to clone, using cd commands, and type the below line. git config --global github.user yourGitUserName git config --global user.email your_email git clone [email protected]:yourGitUserName/YourRepoName.git

https://help.github.com/articles/adding-a-new-ssh-key-to-your-github-account/

What does enctype='multipart/form-data' mean?

when should we use it

Quentin's answer is right: use multipart/form-data if the form contains a file upload, and application/x-www-form-urlencoded otherwise, which is the default if you omit enctype.

I'm going to:

  • add some more HTML5 references
  • explain why he is right with a form submit example

HTML5 references

There are three possibilities for enctype:

How to generate the examples

Once you see an example of each method, it becomes obvious how they work, and when you should use each one.

You can produce examples using:

Save the form to a minimal .html file:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8"/>
  <title>upload</title>
</head>
<body>
<form action="http://localhost:8000" method="post" enctype="multipart/form-data">
  <p><input type="text" name="text1" value="text default">
  <p><input type="text" name="text2" value="a&#x03C9;b">
  <p><input type="file" name="file1">
  <p><input type="file" name="file2">
  <p><input type="file" name="file3">
  <p><button type="submit">Submit</button>
</form>
</body>
</html>

We set the default text value to a&#x03C9;b, which means a?b because ? is U+03C9, which are the bytes 61 CF 89 62 in UTF-8.

Create files to upload:

echo 'Content of a.txt.' > a.txt

echo '<!DOCTYPE html><title>Content of a.html.</title>' > a.html

# Binary file containing 4 bytes: 'a', 1, 2 and 'b'.
printf 'a\xCF\x89b' > binary

Run our little echo server:

while true; do printf '' | nc -l 8000 localhost; done

Open the HTML on your browser, select the files and click on submit and check the terminal.

nc prints the request received.

Tested on: Ubuntu 14.04.3, nc BSD 1.105, Firefox 40.

multipart/form-data

Firefox sent:

POST / HTTP/1.1
[[ Less interesting headers ... ]]
Content-Type: multipart/form-data; boundary=---------------------------735323031399963166993862150
Content-Length: 834

-----------------------------735323031399963166993862150
Content-Disposition: form-data; name="text1"

text default
-----------------------------735323031399963166993862150
Content-Disposition: form-data; name="text2"

a?b
-----------------------------735323031399963166993862150
Content-Disposition: form-data; name="file1"; filename="a.txt"
Content-Type: text/plain

Content of a.txt.

-----------------------------735323031399963166993862150
Content-Disposition: form-data; name="file2"; filename="a.html"
Content-Type: text/html

<!DOCTYPE html><title>Content of a.html.</title>

-----------------------------735323031399963166993862150
Content-Disposition: form-data; name="file3"; filename="binary"
Content-Type: application/octet-stream

a?b
-----------------------------735323031399963166993862150--

For the binary file and text field, the bytes 61 CF 89 62 (a?b in UTF-8) are sent literally. You could verify that with nc -l localhost 8000 | hd, which says that the bytes:

61 CF 89 62

were sent (61 == 'a' and 62 == 'b').

Therefore it is clear that:

  • Content-Type: multipart/form-data; boundary=---------------------------735323031399963166993862150 sets the content type to multipart/form-data and says that the fields are separated by the given boundary string.

    But note that the:

    boundary=---------------------------735323031399963166993862150
    

    has two less dadhes -- than the actual barrier

    -----------------------------735323031399963166993862150
    

    This is because the standard requires the boundary to start with two dashes --. The other dashes appear to be just how Firefox chose to implement the arbitrary boundary. RFC 7578 clearly mentions that those two leading dashes -- are required:

    4.1. "Boundary" Parameter of multipart/form-data

    As with other multipart types, the parts are delimited with a boundary delimiter, constructed using CRLF, "--", and the value of the "boundary" parameter.

  • every field gets some sub headers before its data: Content-Disposition: form-data;, the field name, the filename, followed by the data.

    The server reads the data until the next boundary string. The browser must choose a boundary that will not appear in any of the fields, so this is why the boundary may vary between requests.

    Because we have the unique boundary, no encoding of the data is necessary: binary data is sent as is.

    TODO: what is the optimal boundary size (log(N) I bet), and name / running time of the algorithm that finds it? Asked at: https://cs.stackexchange.com/questions/39687/find-the-shortest-sequence-that-is-not-a-sub-sequence-of-a-set-of-sequences

  • Content-Type is automatically determined by the browser.

    How it is determined exactly was asked at: How is mime type of an uploaded file determined by browser?

application/x-www-form-urlencoded

Now change the enctype to application/x-www-form-urlencoded, reload the browser, and resubmit.

Firefox sent:

POST / HTTP/1.1
[[ Less interesting headers ... ]]
Content-Type: application/x-www-form-urlencoded
Content-Length: 51

text1=text+default&text2=a%CF%89b&file1=a.txt&file2=a.html&file3=binary

Clearly the file data was not sent, only the basenames. So this cannot be used for files.

As for the text field, we see that usual printable characters like a and b were sent in one byte, while non-printable ones like 0xCF and 0x89 took up 3 bytes each: %CF%89!

Comparison

File uploads often contain lots of non-printable characters (e.g. images), while text forms almost never do.

From the examples we have seen that:

  • multipart/form-data: adds a few bytes of boundary overhead to the message, and must spend some time calculating it, but sends each byte in one byte.

  • application/x-www-form-urlencoded: has a single byte boundary per field (&), but adds a linear overhead factor of 3x for every non-printable character.

Therefore, even if we could send files with application/x-www-form-urlencoded, we wouldn't want to, because it is so inefficient.

But for printable characters found in text fields, it does not matter and generates less overhead, so we just use it.

adb devices command not working

Every answer I've read indicates the SUBSYSTEM=="usb". However, my (perhaps ancient) udev needed this to be changed to DRIVER=="usb". At last I can run the adb server as a non-root user... yay.

It can be instructive to look at the output of udevmonitor --env, followed by the output of

udevinfo -a -p <DEVICE_PATH_AS_REPORTED_BY-udevmonitor>

Java: How to read a text file

Just for fun, here's what I'd probably do in a real project, where I'm already using all my favourite libraries (in this case Guava, formerly known as Google Collections).

String text = Files.toString(new File("textfile.txt"), Charsets.UTF_8);
List<Integer> list = Lists.newArrayList();
for (String s : text.split("\\s")) {
    list.add(Integer.valueOf(s));
}

Benefit: Not much own code to maintain (contrast with e.g. this). Edit: Although it is worth noting that in this case tschaible's Scanner solution doesn't have any more code!

Drawback: you obviously may not want to add new library dependencies just for this. (Then again, you'd be silly not to make use of Guava in your projects. ;-)

How do you kill all current connections to a SQL Server 2005 database?

The reason that the approach that Adam suggested won't work is that during the time that you are looping over the active connections new one can be established, and you'll miss those. You could instead use the following approach which does not have this drawback:

-- set your current connection to use master otherwise you might get an error

use master
ALTER DATABASE YourDatabase SET SINGLE_USER WITH ROLLBACK IMMEDIATE 

--do you stuff here 

ALTER DATABASE YourDatabase SET MULTI_USER

"Insufficient Storage Available" even there is lot of free space in device memory

The memory may be in reserve by the OS to be used for running what you normally run (kind of like a swap file). You may be able to squeeze in another app or two by

  • Trying to install them right after a restart, or
  • By force closing some apps that are running (but that second option may not be a good idea -- see the first link),

But the only very good fix might be to

  • Repartition your SD card so that apps can be installed directly to it (see the second link).

Take a look at forum post It was bound to happen: low memory warning!.

The important part is:

The OS knows how much memory it needs to run the apps you already have. This is a perfect example.

Now you may be able to "fool" the OS by force closing some apps that are sitting in RAM. This will increase your "bucket" of memory which may let you install an app, but remember if you do these types of things you will only cause issues down the road.. lagg, error messages, etc. (because you are fooling the OS in thinking you have given it additional memory which in fact you did.. you only force closed).

Another good explanation of what is happening is in forum post Low Internal Memory.

The important part is:

The reason why your internal space is filling up is 3-fold. First, when an app is "moved" to the SD card, it isn't completely moved. Only portions of it actually go. Second, the Dalvik cache of the app is still stored on the internal memory (which takes up a substantial amount of space). Three, the data for apps and all your system settings are stored in the internal memory (yes, some apps use the SD card for portions of their data, but every app has data stored on the internal memory).

And the thread includes suggestions on what partitioning you can do to your SD card to allow 'moar apps'!

how to download image from any web page in java

If you want to save the image and you know its URL you can do this:

try(InputStream in = new URL("http://example.com/image.jpg").openStream()){
    Files.copy(in, Paths.get("C:/File/To/Save/To/image.jpg"));
}

You will also need to handle the IOExceptions which may be thrown.

Get user profile picture by Id

To get largest size of the image

https://graph.facebook.com/{userID}?fields=picture.width(720).height(720) 

or anything else you need as size. Based on experience, type=large is not the largest result you can obtain.

how to insert date and time in oracle?

Try this:

...(to_date('2011/04/22 08:30:00', 'yyyy/mm/dd hh24:mi:ss'));

What is two way binding?

Two-way binding means that any data-related changes affecting the model are immediately propagated to the matching view(s), and that any changes made in the view(s) (say, by the user) are immediately reflected in the underlying model. When app data changes, so does the UI, and conversely.

This is a very solid concept to build a web application on top of, because it makes the "Model" abstraction a safe, atomic data source to use everywhere within the application. Say, if a model, bound to a view, changes, then its matching piece of UI (the view) will reflect that, no matter what. And the matching piece of UI (the view) can safely be used as a mean of collecting user inputs/data, so as to maintain the application data up-to-date.

A good two-way binding implementation should obviously make this connection between a model and some view(s) as simple as possible, from a developper point of view.

It is then quite untrue to say that Backbone does not support two-way binding: while not a core feature of the framework, it can be performed quite simply using Backbone's Events though. It costs a few explicit lines of code for the simple cases; and can become quite hazardous for more complex bindings. Here is a simple case (untested code, written on the fly just for the sake of illustration):

Model = Backbone.Model.extend
  defaults:
    data: ''

View = Backbone.View.extend
  template: _.template("Edit the data: <input type='text' value='<%= data %>' />")

  events:
    # Listen for user inputs, and edit the model.
    'change input': @setData

  initialize: (options) ->
    # Listen for model's edition, and trigger UI update
    @listenTo @model, 'change:data', @render

  render: ->
    @$el.html @template(@model.attributes)
    @

  setData: (e) =>
    e.preventDefault()
    @model.set 'data', $(e.currentTarget).value()

model: new Model()
view = new View {el: $('.someEl'), model: model}

This is a pretty typical pattern in a raw Backbone application. As one can see, it requires a decent amount of (pretty standard) code.

AngularJS and some other alternatives (Ember, Knockout…) provide two-way binding as a first-citizen feature. They abstract many edge-cases under some DSL, and do their best at integrating two-way binding within their ecosystem. Our example would look something like this with AngularJS (untested code, see above):

<div ng-app="app" ng-controller="MainCtrl">
  Edit the data:
  <input name="mymodel.data" ng-model="mymodel.data">
</div>
angular.module('app', [])
  .controller 'MainCtrl', ($scope) ->
    $scope.mymodel = {data: ''}

Rather short!

But, be aware that some fully-fledged two-way binding extensions do exist for Backbone as well (in raw, subjective order of decreasing complexity): Epoxy, Stickit, ModelBinder

One cool thing with Epoxy, for instance, is that it allows you to declare your bindings (model attributes <-> view's DOM element) either within the template (DOM), or within the view implementation (JavaScript). Some people strongly dislike adding "directives" to the DOM/template (such as the ng-* attributes required by AngularJS, or the data-bind attributes of Ember).

Taking Epoxy as an example, one can rework the raw Backbone application into something like this (…):

Model = Backbone.Model.extend
  defaults:
    data: ''

View = Backbone.Epoxy.View.extend
  template: _.template("Edit the data: <input type='text' />")
  # or, using the inline form: <input type='text' data-bind='value:data' />

  bindings:
    'input': 'value:data'

  render: ->
    @$el.html @template(@model.attributes)
    @

model: new Model()
view = new View {el: $('.someEl'), model: model}

All in all, pretty much all "mainstream" JS frameworks support two-way binding. Some of them, such as Backbone, do require some extra work to make it work smoothly, but those are the same which do not enforce a specific way to do it, to begin with. So it is really about your state of mind.

Also, you may be interested in Flux, a different architecture for web applications promoting one-way binding through a circular pattern. It is based on the concept of fast, holistic re-rendering of UI components upon any data change to ensure cohesiveness and make it easier to reason about the code/dataflow. In the same trend, you might want to check the concept of MVI (Model-View-Intent), for instance Cycle.

How to get a value from a cell of a dataframe?

To get the full row's value as JSON (instead of a Serie):

row = df.iloc[0]

Use the to_json method like bellow:

row.to_json()

How to animate button in android?

Dependency

Add it in your root build.gradle at the end of repositories:

allprojects {
repositories {
    ...
    maven { url "https://jitpack.io" }
}}

and then add dependency dependencies { compile 'com.github.varunest:sparkbutton:1.0.5' }

Usage

XML

<com.varunest.sparkbutton.SparkButton
        android:id="@+id/spark_button"
        android:layout_width="40dp"
        android:layout_height="40dp"
        app:sparkbutton_activeImage="@drawable/active_image"
        app:sparkbutton_inActiveImage="@drawable/inactive_image"
        app:sparkbutton_iconSize="40dp"
        app:sparkbutton_primaryColor="@color/primary_color"
        app:sparkbutton_secondaryColor="@color/secondary_color" />

Java (Optional)

SparkButton button  = new SparkButtonBuilder(context)
            .setActiveImage(R.drawable.active_image)
            .setInActiveImage(R.drawable.inactive_image)
            .setDisabledImage(R.drawable.disabled_image)
            .setImageSizePx(getResources().getDimensionPixelOffset(R.dimen.button_size))
            .setPrimaryColor(ContextCompat.getColor(context, R.color.primary_color))
            .setSecondaryColor(ContextCompat.getColor(context, R.color.secondary_color))
            .build();

SQL, How to convert VARCHAR to bigint?

I think your code is right. If you run the following code it converts the string '60' which is treated as varchar and it returns integer 60, if there is integer containing string in second it works.

select CONVERT(bigint,'60') as seconds 

and it returns

60

Format Date/Time in XAML in Silverlight

In SL5 I found this to work:

<TextBlock Name="textBlock" Text="{Binding JustificationDate, StringFormat=dd-MMMM-yy hh:mm}">
<TextBlock Name="textBlock" Text="{Binding JustificationDate, StringFormat='Justification Date: \{0:dd-MMMM-yy hh:mm\}'}">

Oracle: Import CSV file

SQL Loader is the way to go. I recently loaded my table from a csv file,new to this concept,would like to share an example.

LOAD DATA
    infile '/ipoapplication/utl_file/LBR_HE_Mar16.csv'
    REPLACE
    INTO TABLE LOAN_BALANCE_MASTER_INT
    fields terminated by ',' optionally enclosed by '"'
    (
    ACCOUNT_NO,
    CUSTOMER_NAME,
    LIMIT,
    REGION

    )

Place the control file and csv at the same location on the server. Locate the sqlldr exe and invoce it.

sqlldr userid/passwd@DBname control= Ex : sqlldr abc/xyz@ora control=load.ctl

Hope it helps.

CALL command vs. START with /WAIT option

For exe files, I suppose the differences are nearly unimportant.
But to start an exe you don't even need CALL.

When starting another batch it's a big difference,
as CALL will start it in the same window and the called batch has access to the same variable context.
So it can also change variables which affects the caller.

START will create a new cmd.exe for the called batch and without /b it will open a new window.
As it's a new context, variables can't be shared.

Differences

Using start /wait <prog>
- Changes of environment variables are lost when the <prog> ends
- The caller waits until the <prog> is finished

Using call <prog>
- For exe it can be ommited, because it's equal to just starting <prog>
- For an exe-prog the caller batch waits or starts the exe asynchronous, but the behaviour depends on the exe itself.
- For batch files, the caller batch continues, when the called <batch-file> finishes, WITHOUT call the control will not return to the caller batch

Addendum:

Using CALL can change the parameters (for batch and exe files), but only when they contain carets or percent signs.

call myProg param1 param^^2 "param^3" %%path%%

Will be expanded to (from within an batch file)

myProg param1 param2 param^^3 <content of path>

Check whether an array is empty

In PHP, even if the individual items within an array or properties of an object are empty, the array or object will not evaluate to empty using the empty($subject) function. In other words, cobbling together a bunch of data that individually tests as "empty" creates a composite that is non-empty. Use the following PHP function to determine if the items in an array or properties of an object are empty:

function functionallyEmpty($o)
{
  if (empty($o)) return true;
  else if (is_numeric($o)) return false;
  else if (is_string($o)) return !strlen(trim($o)); 
  else if (is_object($o)) return functionallyEmpty((array)$o);

  // If it's an array!
  foreach($o as $element) 
    if (functionallyEmpty($element)) continue; 
    else return false; 

  // all good.
  return true;
}

Example Usage:

$subject = array('', '', '');

empty($subject); // returns false
functionallyEmpty($subject); // returns true

class $Subject {
    a => '',
    b => array()
}

$theSubject = new Subject();

empty($theSubject); // returns false
functionallyEmpty($theSubject); // returns true

Web scraping with Python

Use urllib2 in combination with the brilliant BeautifulSoup library:

import urllib2
from BeautifulSoup import BeautifulSoup
# or if you're using BeautifulSoup4:
# from bs4 import BeautifulSoup

soup = BeautifulSoup(urllib2.urlopen('http://example.com').read())

for row in soup('table', {'class': 'spad'})[0].tbody('tr'):
    tds = row('td')
    print tds[0].string, tds[1].string
    # will print date and sunrise

Unable to locate Spring NamespaceHandler for XML schema namespace [http://www.springframework.org/schema/security]

In my case, this was caused by custom manifest entries added by the maven-jar-plugin.

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-jar-plugin</artifactId>
    <version>2.6</version>
    <configuration>
        <archive>
            <index>true</index>
            <manifest>
                <addClasspath>true</addClasspath>
            </manifest>
            <manifestEntries>
                <git>${buildNumber}</git>
                <build-time>${timestamp}</build-time>
            </manifestEntries>
        </archive>
    </configuration>
</plugin>

Removing the following entries fixed the problem

<index>true</index>
<manifest>
    <addClasspath>true</addClasspath>
</manifest>

How to disable horizontal scrolling of UIScrollView?

Introduced in iOS 11 is a new property on UIScrollView

var contentLayoutGuide: UILayoutGuide

The documentation states that you:

Use this layout guide when you want to create Auto Layout constraints related to the content area of a scroll view.

Along with any other Autolayout constraints that you might be adding you will want to constrain the widthAnchor of the UIScrollView's contentLayoutGuide to be the same size as the "frame". You can use the frameLayoutGuide (also introduced in iOS 11) or any external width (such as your superView's.)

example:

NSLayoutConstraint.activate([
  scrollView.contentLayoutGuide.widthAnchor.constraint(equalTo: self.widthAnchor)
])

Documentation: https://developer.apple.com/documentation/uikit/uiscrollview/2865870-contentlayoutguide

how to delete default values in text field using selenium?

If you're looking for a solution from Selenium RC, you can use simply

// assuming 'selenium' is a healthy Selenium instance
selenium.type("someLocator", "");

How to print formatted BigDecimal values?

public static String currencyFormat(BigDecimal n) {
    return NumberFormat.getCurrencyInstance().format(n);
}

It will use your JVM’s current default Locale to choose your currency symbol. Or you can specify a Locale.

NumberFormat.getInstance(Locale.US)

For more info, see NumberFormat class.

Converting a sentence string to a string array of words in Java

The easiest and best answer I can think of is to use the following method defined on the java string -

String[] split(String regex)

And just do "This is a sample sentence".split(" "). Because it takes a regex, you can do more complicated splits as well, which can include removing unwanted punctuation and other such characters.

Find row where values for column is maximal in a pandas DataFrame

Both above answers would only return one index if there are multiple rows that take the maximum value. If you want all the rows, there does not seem to have a function. But it is not hard to do. Below is an example for Series; the same can be done for DataFrame:

In [1]: from pandas import Series, DataFrame

In [2]: s=Series([2,4,4,3],index=['a','b','c','d'])

In [3]: s.idxmax()
Out[3]: 'b'

In [4]: s[s==s.max()]
Out[4]: 
b    4
c    4
dtype: int64

What are projection and selection?

Projection: what ever typed in select clause i.e, 'column list' or '*' or 'expressions' that becomes under projection.

*selection:*what type of conditions we are applying on that columns i.e, getting the records that comes under selection.

For example:

  SELECT empno,ename,dno,job from Emp 
     WHERE job='CLERK'; 

in the above query the columns "empno,ename,dno,job" those comes under projection, "where job='clerk'" comes under selection

import httplib ImportError: No module named httplib

I had this issue when I was trying to make my Docker container smaller. It was because I'd installed Python 2.7 with:

apt-get install -y --no-install-recommends python

And I should not have included the --no-install-recommends flag:

apt-get install -y python

mysql delete under safe mode

You can trick MySQL into thinking you are actually specifying a primary key column. This allows you to "override" safe mode.

Assuming you have a table with an auto-incrementing numeric primary key, you could do the following:

DELETE FROM tbl WHERE id <> 0

Android Text over image

For this you can use only one TextView with android:drawableLeft/Right/Top/Bottom to position a Image to the TextView. Furthermore you can use some padding between the TextView and the drawable with android:drawablePadding=""

Use it like this:

<TextView
    android:id="@+id/textAndImage"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"

    android:drawableBottom="@drawable/yourDrawable"
    android:drawablePadding="10dp" 
    android:text="Look at the drawable below"/>

With this you don't need an extra ImageView. It's also possible to use two drawables on more than one side of the TextView.

The only problem you will face by using this, is that the drawable can't be scaled the way of an ImageView.

How to add header to a dataset in R?

You can do the following:

Load the data:

test <- read.csv(
          "http://archive.ics.uci.edu/ml/machine-learning-databases/breast-cancer-wisconsin/breast-cancer-wisconsin.data",
          header=FALSE)

Note that the default value of the header argument for read.csv is TRUE so in order to get all lines you need to set it to FALSE.

Add names to the different columns in the data.frame

names(test) <- c("A","B","C","D","E","F","G","H","I","J","K")

or alternative and faster as I understand (not reloading the entire dataset):

colnames(test) <- c("A","B","C","D","E","F","G","H","I","J","K")

Using JSON POST Request

Modern browsers do not currently implement JSONRequest (as far as I know) since it is only a draft right now. I have found someone who has implemented it as a library that you can include in your page: http://devpro.it/JSON/files/JSONRequest-js.html (please note that it has a few dependencies).

Otherwise, you might want to go with another JS library like jQuery or Mootools.

Using jQuery to compare two arrays of Javascript objects

Change array to string and compare

var arr = [1,2,3], 
arr2 = [1,2,3]; 
console.log(arr.toString() === arr2.toString());

iOS: Convert UTC NSDate to local Timezone

Convert your UTC date to Local Date

-(NSString *)getLocalDateTimeFromUTC:(NSString *)strDate
{
    NSDateFormatter *dtFormat = [[NSDateFormatter alloc] init];
    [dtFormat setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    [dtFormat setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"UTC"]];
    NSDate *aDate = [dtFormat dateFromString:strDate];

    [dtFormat setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    [dtFormat setTimeZone:[NSTimeZone systemTimeZone]];

    return [dtFormat stringFromDate:aDate];
}

Use Like This

NSString *localDate = [self getLocalDateTimeFromUTC:@"yourUTCDate"];

Apache: client denied by server configuration

I had this issue using Vesta CP and for me, the trick was remove .htaccess and try to access to any file again.

That resulted on regeneration of .htaccess file and then I was able to access to my files.

SQL not a single-group group function

Well the problem simply-put is that the SUM(TIME) for a specific SSN on your query is a single value, so it's objecting to MAX as it makes no sense (The maximum of a single value is meaningless).

Not sure what SQL database server you're using but I suspect you want a query more like this (Written with a MSSQL background - may need some translating to the sql server you're using):

SELECT TOP 1 SSN, SUM(TIME)
FROM downloads
GROUP BY SSN
ORDER BY 2 DESC

This will give you the SSN with the highest total time and the total time for it.

Edit - If you have multiple with an equal time and want them all you would use:

SELECT
SSN, SUM(TIME)
FROM downloads
GROUP BY SSN
HAVING SUM(TIME)=(SELECT MAX(SUM(TIME)) FROM downloads GROUP BY SSN))

What is the difference between --save and --save-dev?

People use npm on production to do wicked cool stuff, Node.js is an example of this, so you don't want all your dev tools being run.

If you are using gulp (or similar) to create build files to put on your server then it doesn't really matter.

Windows Task Scheduler doesn't start batch file task

I had the same problem and none of the solutions worked. When I checked the history I figured out the issue. I had this warning

Task Scheduler did not launch task "\TASK_NAME"  because instance "{34a206d4-7fce-3895-bfcd-2456f6ed6533}"  of the same task is already running.

In the settings tab there is a drop down option for "If the task is already running, then the following rule applies:" and the default is "Do not start a new instance". Change that to "Run a new instance in parallel" or "Stop the existing instance" based on what you actually need to be done.

I know it's an old thread and multiple solutions are good here, this is just what worked for me. Hope it helps.

Creating a file name as a timestamp in a batch job

I know this thread is old but I just want to add this here because it helped me alot trying to figure this all out and its clean. The nice thing about this is you could put it in a loop for a batch file that's always running. Server up-time log or something. That's what I use it for anyways. I hope this helps someone someday.

@setlocal enableextensions enabledelayedexpansion
@echo off

call :timestamp freshtime freshdate
echo %freshdate% - %freshtime% - Some data >> "%freshdate - Somelog.log"

:timestamp
set hour=%time:~0,2%
if "%hour:~0,1%" == " " set hour=0%hour:~1,1%
set min=%time:~3,2%
if "%min:~0,1%" == " " set min=0%min:~1,1%
set secs=%time:~6,2%
if "%secs:~0,1%" == " " set secs=0%secs:~1,1%
set FreshTime=%hour%:%min%:%secs%

set year=%date:~-4%
set month=%date:~4,2%
if "%month:~0,1%" == " " set month=0%month:~1,1%
set day=%date:~7,2%
if "%day:~0,1%" == " " set day=0%day:~1,1%
set FreshDate=%month%.%day%.%year%

Disable elastic scrolling in Safari

None of the 'overflow' solutions worked for me. I'm coding a parallax effect with JavaScript using jQuery. In Chrome and Safari on OSX the elastic/rubber-band effect was messing up my scroll numbers, since it actually scrolls past the document's height and updates the window variables with out-of-boundary numbers. What I had to do was check if the scrolled amount was larger than the actual document's height, like so:

$(window).scroll(
    function() {
        if ($(window).scrollTop() + $(window).height() > $(document).height()) return;
        updateScroll(); // my own function to do my parallaxing stuff
    }
);

How to get the squared symbol (²) to display in a string

No need to get too complicated. If all you need is ² then use the unicode representation.

http://en.wikipedia.org/wiki/Unicode_subscripts_and_superscripts

(which is how I assume you got the ² to appear in your question. )

Concat a string to SELECT * MySql

You cannot concatenate multiple fields with a string. You need to select a field instand of all (*).

Is it possible to use JS to open an HTML select to show its option list?

I had this problem...and found a workable solution.

I didn't want the select box to show until the user clicked on some plain HTML. So I overlayed the select element with opacity=.01. Upon clicking, I changed it back to opacity=100. This allowed me to hide the select, and when the user clicked the text the select appeared with the options showing.

How to delete rows in tables that contain foreign keys to other tables

You can alter a foreign key constraint with delete cascade option as shown below. This will delete chind table rows related to master table rows when deleted.

ALTER TABLE MasterTable
ADD CONSTRAINT fk_xyz 
FOREIGN KEY (xyz) 
REFERENCES ChildTable (xyz) ON DELETE CASCADE 

How to print from Flask @app.route to python console

I tried running @Viraj Wadate's code, but couldn't get the output from app.logger.info on the console.

To get INFO, WARNING, and ERROR messages in the console, the dictConfig object can be used to create logging configuration for all logs (source):

from logging.config import dictConfig
from flask import Flask


dictConfig({
    'version': 1,
    'formatters': {'default': {
        'format': '[%(asctime)s] %(levelname)s in %(module)s: %(message)s',
    }},
    'handlers': {'wsgi': {
        'class': 'logging.StreamHandler',
        'stream': 'ext://flask.logging.wsgi_errors_stream',
        'formatter': 'default'
    }},
    'root': {
        'level': 'INFO',
        'handlers': ['wsgi']
    }
})


app = Flask(__name__)

@app.route('/')
def index():
    return "Hello from Flask's test environment"

@app.route('/print')
def printMsg():
    app.logger.warning('testing warning log')
    app.logger.error('testing error log')
    app.logger.info('testing info log')
    return "Check your console"

if __name__ == '__main__':
    app.run(debug=True)

How to check which locks are held on a table

I use a Dynamic Management View (DMV) to capture locks as well as the object_id or partition_id of the item that is locked.

(MUST switch to the Database you want to observe to get object_id)

SELECT 
     TL.resource_type,
     TL.resource_database_id,
     TL.resource_associated_entity_id,
     TL.request_mode,
     TL.request_session_id,
     WT.blocking_session_id,
     O.name AS [object name],
     O.type_desc AS [object descr],
     P.partition_id AS [partition id],
     P.rows AS [partition/page rows],
     AU.type_desc AS [index descr],
     AU.container_id AS [index/page container_id]
FROM sys.dm_tran_locks AS TL
INNER JOIN sys.dm_os_waiting_tasks AS WT 
 ON TL.lock_owner_address = WT.resource_address
LEFT OUTER JOIN sys.objects AS O 
 ON O.object_id = TL.resource_associated_entity_id
LEFT OUTER JOIN sys.partitions AS P 
 ON P.hobt_id = TL.resource_associated_entity_id
LEFT OUTER JOIN sys.allocation_units AS AU 
 ON AU.allocation_unit_id = TL.resource_associated_entity_id;

Show a child form in the centre of Parent form in C#

As a sub form i think it's not gonna Start in the middle of the parent form until you Show it as a Dialog. .......... Form2.ShowDialog();

i was about to make About Form. and this is perfect that's i am searching for. and untill you close the About_form you cant Touch/click anythings of parents Form once you Click for About_Form (in my case) .Coz its Showing as Dialog