Programs & Examples On #Falcon

Falcon is an open source, multi-paradigm programming language.

Appending to list in Python dictionary

Is there a more elegant way to write this code?

Use collections.defaultdict:

from collections import defaultdict

dates_dict = defaultdict(list)
for key, date in cur:
    dates_dict[key].append(date)

How to change background color in the Notepad++ text editor?

You may need admin access to do it on your system.

  1. Create a folder 'themes' in the Notepad++ installation folder i.e. C:\Program Files (x86)\Notepad++
  2. Search or visit pages like http://timtrott.co.uk/notepad-colour-schemes/ to download the favourite theme. It will be an SML file.
    • Note: I prefer Neon any day.
  3. Download the themes from the site and drag them to the themes folder.
    • Note: I was unable to copy-paste or create new files in 'themes' folder so I used drag and that worked.
  4. Follow the steps provided by @triforceofcourage to select the new theme in Notepad++ preferences.

jQuery select change event get selected option

I find this shorter and cleaner. Besides, you can iterate through selected items if there are more than one;

$('select').on('change', function () {
     var selectedValue = this.selectedOptions[0].value;
     var selectedText  = this.selectedOptions[0].text;
});

Laravel Eloquent get results grouped by days

You can filter the results based on formatted date using mysql (See here for Mysql/Mariadb help) and use something like this in laravel-5.4:

Model::selectRaw("COUNT(*) views, DATE_FORMAT(created_at, '%Y %m %e') date")
    ->groupBy('date')
    ->get();

How to read connection string in .NET Core?

Too late, but after reading all helpful answers and comments, I ended up using Microsoft.Extensions.Configuration.Binder extension package and play a little around to get rid of hardcoded configuration keys.

My solution:

IConfigSection.cs

public interface IConfigSection
{
}

ConfigurationExtensions.cs

public static class ConfigurationExtensions
{
    public static TConfigSection GetConfigSection<TConfigSection>(this IConfiguration configuration) where TConfigSection : IConfigSection, new()
    {
        var instance = new TConfigSection();
        var typeName = typeof(TConfigSection).Name;
        configuration.GetSection(typeName).Bind(instance);

        return instance;
    }
}

appsettings.json

{
   "AppConfigSection": {
      "IsLocal": true
   },
   "ConnectionStringsConfigSection": {
      "ServerConnectionString":"Server=.;Database=MyDb;Trusted_Connection=True;",
      "LocalConnectionString":"Data Source=MyDb.db",
   },
}

To access a strongly typed config, you just need to create a class for that, which implements IConfigSection interface(Note: class names and field names should exactly match section in appsettings.json)

AppConfigSection.cs

public class AppConfigSection: IConfigSection
{
    public bool IsLocal { get; set; }
}

ConnectionStringsConfigSection.cs

public class ConnectionStringsConfigSection : IConfigSection
{
    public string ServerConnectionString { get; set; }
    public string LocalConnectionString { get; set; }

    public ConnectionStringsConfigSection()
    {
        // set default values to avoid null reference if
        // section is not present in appsettings.json
        ServerConnectionString = string.Empty;
        LocalConnectionString = string.Empty;
    }
}

And finally, a usage example:

Startup.cs

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    public void ConfigureServices(IServiceCollection services)
    {
        // some stuff

        var app = Configuration.GetConfigSection<AppConfigSection>();
        var connectionStrings = Configuration.GetConfigSection<ConnectionStringsConfigSection>();

        services.AddDbContext<AppDbContext>(options =>
        {
            if (app.IsLocal)
            {
                options.UseSqlite(connectionStrings.LocalConnectionString);
            }
            else
            {
                options.UseSqlServer(connectionStrings.ServerConnectionString);
            }
        });

        // other stuff
    }
}

To make it neat, you can move above code into an extension method.

That's it, no hardcoded configuration keys.

Can you do a partial checkout with Subversion?

If you already have the full local copy, you can remove unwanted sub folders by using --set-depth command.

svn update --set-depth=exclude www

See: http://blogs.collab.net/subversion/sparse-directories-now-with-exclusion

The set-depth command support multipile paths.

Updating the root local copy will not change the depth of the modified folder.

To restore the folder to being recusively checkingout, you could use --set-depth again with infinity param.

svn update --set-depth=infinity www

angular-cli where is webpack.config.js file - new angular6 does not support ng eject

What I am thinking is having webpack would be easy when production release.

FYI : https://github.com/Piusha/ngx-lazyloading

How does numpy.histogram() work?

import numpy as np    
hist, bin_edges = np.histogram([1, 1, 2, 2, 2, 2, 3], bins = range(5))

Below, hist indicates that there are 0 items in bin #0, 2 in bin #1, 4 in bin #3, 1 in bin #4.

print(hist)
# array([0, 2, 4, 1])   

bin_edges indicates that bin #0 is the interval [0,1), bin #1 is [1,2), ..., bin #3 is [3,4).

print (bin_edges)
# array([0, 1, 2, 3, 4]))  

Play with the above code, change the input to np.histogram and see how it works.


But a picture is worth a thousand words:

import matplotlib.pyplot as plt
plt.bar(bin_edges[:-1], hist, width = 1)
plt.xlim(min(bin_edges), max(bin_edges))
plt.show()   

enter image description here

How to get request URI without context path?

With Spring you can do:

String path = new UrlPathHelper().getPathWithinApplication(request);

SQL select statements with multiple tables

Select * from people p, address a where  p.id = a.person_id and a.zip='97229';

Or you must TRY using JOIN which is a more efficient and better way to do this as Gordon Linoff in the comments below also says that you need to learn this.

SELECT p.*, a.street, a.city FROM persons AS p
JOIN address AS a ON p.id = a.person_id
WHERE a.zip = '97299';

Here p.* means it will show all the columns of PERSONS table.

javascript toISOString() ignores timezone offset

Using moment.js, you can use keepOffset parameter of toISOString:

toISOString(keepOffset?: boolean): string;

moment().toISOString(true)

Run certain code every n seconds

Save yourself a schizophrenic episode and use the Advanced Python scheduler: http://pythonhosted.org/APScheduler

The code is so simple:

from apscheduler.scheduler import Scheduler

sched = Scheduler()
sched.start()

def some_job():
    print "Every 10 seconds"

sched.add_interval_job(some_job, seconds = 10)

....
sched.shutdown()

Import file size limit in PHPMyAdmin

With WAMP, on Windows10, open

c:\wamp64\alias\phpmyadmin.conf

and change 128 by 256 at the end of these lines

  php_admin_value upload_max_filesize 128M
  php_admin_value post_max_size 128M

Restart WAMP

Authenticated HTTP proxy with Java

Most of the answer is in existing replies, but for me not quite. This is what works for me with java.net.HttpURLConnection (I have tested all the cases with JDK 7 and JDK 8). Note that you do not have to use the Authenticator class.

Case 1 : Proxy without user authentication, access HTTP resources

-Dhttp.proxyHost=myproxy -Dhttp.proxyPort=myport

Case 2 : Proxy with user authentication, access HTTP resources

-Dhttp.proxyHost=myproxy -Dhttp.proxyPort=myport -Dhttps.proxyUser=myuser -Dhttps.proxyPassword=mypass

Case 3 : Proxy without user authentication, access HTTPS resources (SSL)

-Dhttps.proxyHost=myproxy -Dhttps.proxyPort=myport 

Case 4 : Proxy with user authentication, access HTTPS resources (SSL)

-Dhttps.proxyHost=myproxy -Dhttps.proxyPort=myport -Dhttps.proxyUser=myuser -Dhttps.proxyPassword=mypass

Case 5 : Proxy without user authentication, access both HTTP and HTTPS resources (SSL)

-Dhttp.proxyHost=myproxy -Dhttp.proxyPort=myport -Dhttps.proxyHost=myproxy -Dhttps.proxyPort=myport 

Case 6 : Proxy with user authentication, access both HTTP and HTTPS resources (SSL)

-Dhttp.proxyHost=myproxy -Dhttp.proxyPort=myport -Dhttp.proxyUser=myuser -Dhttp.proxyPassword=mypass -Dhttps.proxyHost=myproxy -Dhttps.proxyPort=myport -Dhttps.proxyUser=myuser -Dhttps.proxyPassword=mypass

You can set the properties in the with System.setProperty("key", "value) too.

To access HTTPS resource you may have to trust the resource by downloading the server certificate and saving it in a trust store and then using that trust store. ie

 System.setProperty("javax.net.ssl.trustStore", "c:/temp/cert-factory/my-cacerts");
 System.setProperty("javax.net.ssl.trustStorePassword", "changeit");

applying css to specific li class

The CSS you have applies color #c1c1c1 to all <a> elements.

And it also applies color #c1c1c1 to the first <li> element.

Perhaps the code you posted is missing something because I don't see any other colors being defined.

How to get "their" changes in the middle of conflicting Git rebase?

You want to use:

git checkout --ours foo/bar.java
git add foo/bar.java

If you rebase a branch feature_x against main (i.e. running git rebase main while on branch feature_x), during rebasing ours refers to main and theirs to feature_x.

As pointed out in the git-rebase docs:

Note that a rebase merge works by replaying each commit from the working branch on top of the branch. Because of this, when a merge conflict happens, the side reported as ours is the so-far rebased series, starting with <upstream>, and theirs is the working branch. In other words, the sides are swapped.

For further details read this thread.

Excel formula to search if all cells in a range read "True", if not, then show "False"

=IF(COUNTIF(A1:D1,FALSE)>0,FALSE,TRUE)

(or you can specify any other range to look in)

Twitter bootstrap float div right

This does the trick, without the need to add an inline style

<div class="row-fluid">
    <div class="span6">
        <p>text left</p>
    </div>
    <div class="span6">
        <div class="pull-right">
            <p>text right</p>
        </div>
    </div>
</div>

The answer is in nesting another <div> with the "pull-right" class. Combining the two classes won't work.

using where and inner join in mysql

You can use as many joins as you want, however, the more you use the more it will impact performance

Convert NSData to String?

Objective-C

You can use (see NSString Class Reference)

- (id)initWithData:(NSData *)data encoding:(NSStringEncoding)encoding

Example:

NSString *myString = [[NSString alloc] initWithData:myData encoding:NSUTF8StringEncoding];

Remark: Please notice the NSData value must be valid for the encoding specified (UTF-8 in the example above), otherwise nil will be returned:

Returns nil if the initialization fails for some reason (for example if data does not represent valid data for encoding).

Prior Swift 3.0

String(data: yourData, encoding: NSUTF8StringEncoding)

Swift 3.0 Onwards

String(data: yourData, encoding: .utf8)

See String#init(data:encoding:) Reference

getting the last item in a javascript object

Let obj be your object. Exec:

(_ => _[Object.keys(_).pop()])( obj )

Write to Windows Application Event Log

Yes, there is a way to write to the event log you are looking for. You don't need to create a new source, just simply use the existent one, which often has the same name as the EventLog's name and also, in some cases like the event log Application, can be accessible without administrative privileges*.

*Other cases, where you cannot access it directly, are the Security EventLog, for example, which is only accessed by the operating system.

I used this code to write directly to the event log Application:

using (EventLog eventLog = new EventLog("Application")) 
{
    eventLog.Source = "Application"; 
    eventLog.WriteEntry("Log message example", EventLogEntryType.Information, 101, 1); 
}

As you can see, the EventLog source is the same as the EventLog's name. The reason of this can be found in Event Sources @ Windows Dev Center (I bolded the part which refers to source name):

Each log in the Eventlog key contains subkeys called event sources. The event source is the name of the software that logs the event. It is often the name of the application or the name of a subcomponent of the application if the application is large. You can add a maximum of 16,384 event sources to the registry.

Remove all special characters from a string in R?

Convert the Special characters to apostrophe,

Data  <- gsub("[^0-9A-Za-z///' ]","'" , Data ,ignore.case = TRUE)

Below code it to remove extra ''' apostrophe

Data <- gsub("''","" , Data ,ignore.case = TRUE)

Use gsub(..) function for replacing the special character with apostrophe

How to open a website when a Button is clicked in Android application?

Import import android.net.Uri;

Intent openURL = new Intent(android.content.Intent.ACTION_VIEW);
openURL.setData(Uri.parse("http://www.example.com"));
startActivity(openURL);

or it can be done using,

TextView textView = (TextView)findViewById(R.id.yourID);

textView.setOnClickListener(new OnClickListener() {
    public void onClick(View v) {
        Intent intent = new Intent();
        intent.setAction(Intent.ACTION_VIEW);
        intent.addCategory(Intent.CATEGORY_BROWSABLE);
        intent.setData(Uri.parse("http://www.typeyourURL.com"));
        startActivity(intent);
    } });

Argument of type 'X' is not assignable to parameter of type 'X'

In my case, strangely enough, I was missing the import of the class it was complaining about and my IDE didn't detect it.

How to extract duration time from ffmpeg output?

Best Solution: cut the export do get something like 00:05:03.22

ffmpeg -i input 2>&1 | grep Duration | cut -c 13-23

Does reading an entire file leave the file handle open?

The answer to that question depends somewhat on the particular Python implementation.

To understand what this is all about, pay particular attention to the actual file object. In your code, that object is mentioned only once, in an expression, and becomes inaccessible immediately after the read() call returns.

This means that the file object is garbage. The only remaining question is "When will the garbage collector collect the file object?".

in CPython, which uses a reference counter, this kind of garbage is noticed immediately, and so it will be collected immediately. This is not generally true of other python implementations.

A better solution, to make sure that the file is closed, is this pattern:

with open('Path/to/file', 'r') as content_file:
    content = content_file.read()

which will always close the file immediately after the block ends; even if an exception occurs.

Edit: To put a finer point on it:

Other than file.__exit__(), which is "automatically" called in a with context manager setting, the only other way that file.close() is automatically called (that is, other than explicitly calling it yourself,) is via file.__del__(). This leads us to the question of when does __del__() get called?

A correctly-written program cannot assume that finalizers will ever run at any point prior to program termination.

-- https://devblogs.microsoft.com/oldnewthing/20100809-00/?p=13203

In particular:

Objects are never explicitly destroyed; however, when they become unreachable they may be garbage-collected. An implementation is allowed to postpone garbage collection or omit it altogether — it is a matter of implementation quality how garbage collection is implemented, as long as no objects are collected that are still reachable.

[...]

CPython currently uses a reference-counting scheme with (optional) delayed detection of cyclically linked garbage, which collects most objects as soon as they become unreachable, but is not guaranteed to collect garbage containing circular references.

-- https://docs.python.org/3.5/reference/datamodel.html#objects-values-and-types

(Emphasis mine)

but as it suggests, other implementations may have other behavior. As an example, PyPy has 6 different garbage collection implementations!

Materialize CSS - Select Doesn't Seem to Render

Only this worked for me:

$(document).ready(function(){
    $('select').not('.disabled').formSelect();
});

Adding text to ImageView in Android

To draw text directly on canvas do the following:

  1. Create a member Paint object in myImageView constructor

    Paint mTextPaint = new Paint();
    
  2. Use canvas.drawText in your myImageView.onDraw() method:

    canvas.drawText("My fancy text", xpos, ypos, mTextPaint);
    

Explore Paint and Canvas class documentation to add fancy effects.

What Language is Used To Develop Using Unity

When you build for iPhone in Unity it does Ahead of Time (AOT) compilation of your mono assembly (written in C# or JavaScript) to native ARM code.

The authoring tool also creates a stub xcode project and references that compiled lib. You can add objective C code to this xcode project if there is native stuff you want to do that isn't exposed in Unity's environment yet (e.g. accessing the compass and/or gyroscope).

Jackson enum Serializing and DeSerializer

There are various approaches that you can take to accomplish deserialization of a JSON object to an enum. My favorite style is to make an inner class:

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.annotation.JsonProperty;
import org.hibernate.validator.constraints.NotEmpty;

import java.util.Arrays;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.Collectors;

import static com.fasterxml.jackson.annotation.JsonFormat.Shape.OBJECT;

@JsonFormat(shape = OBJECT)
public enum FinancialAccountSubAccountType {
  MAIN("Main"),
  MAIN_DISCOUNT("Main Discount");

  private final static Map<String, FinancialAccountSubAccountType> ENUM_NAME_MAP;
  static {
    ENUM_NAME_MAP = Arrays.stream(FinancialAccountSubAccountType.values())
      .collect(Collectors.toMap(
        Enum::name,
        Function.identity()));
  }

  private final String displayName;

  FinancialAccountSubAccountType(String displayName) {
    this.displayName = displayName;
  }

  @JsonCreator
  public static FinancialAccountSubAccountType fromJson(Request request) {
    return ENUM_NAME_MAP.get(request.getCode());
  }

  @JsonProperty("name")
  public String getDisplayName() {
    return displayName;
  }

  private static class Request {
    @NotEmpty(message = "Financial account sub-account type code is required")
    private final String code;
    private final String displayName;

    @JsonCreator
    private Request(@JsonProperty("code") String code,
                    @JsonProperty("name") String displayName) {
      this.code = code;
      this.displayName = displayName;
    }

    public String getCode() {
      return code;
    }

    @JsonProperty("name")
    public String getDisplayName() {
      return displayName;
    }
  }
}

Oracle (ORA-02270) : no matching unique or primary key for this column-list error

The scheme is correct, User.ID must be the primary key of User, Job.ID should be the primary key of Job and Job.UserID should be a foreign key to User.ID. Also, your commands appear to be syntactically correct.

So what could be wrong? I believe you have at least a Job.UserID which doesn't have a pair in User.ID. For instance, if all values of User.ID are: 1,2,3,4,6,7,8 and you have a value of Job.UserID of 5 (which is not among 1,2,3,4,6,7,8, which are the possible values of UserID), you will not be able to create your foreign key constraint. Solution:

delete from Job where UserID in (select distinct User.ID from User);

will delete all jobs with nonexistent users. You might want to migrate these to a copy of this table which will contain archive data.

How to retrieve checkboxes values in jQuery

If you want to insert the value of any checkbox immediately as it is being checked then this should work for you:

$(":checkbox").click(function(){
  $("#id").text(this.value)
})

Install specific branch from github using Npm

Another approach would be to add the following line to package.json dependencies:

"package-name": "user/repo#branch"

For example:

"dependencies": {
    ... other dependencies ...

    "react-native": "facebook/react-native#master"
}

And then do npm install or yarn install

MYSQL order by both Ascending and Descending sorting

You can do that in this way:

ORDER BY `products`.`product_category_id` DESC ,`naam` ASC

Have a look at ORDER BY Optimization

Understanding Bootstrap's clearfix class

When a clearfix is used in a parent container, it automatically wraps around all the child elements.

It is usually used after floating elements to clear the float layout.

When float layout is used, it will horizontally align the child elements. Clearfix clears this behaviour.

Example - Bootstrap Panels

In bootstrap, when the class panel is used, there are 3 child types: panel-header, panel-body, panel-footer. All of which have display:block layout but panel-body has a clearfix pre-applied. panel-body is a main container type whereas panel-header & panel-footer isn't intended to be a container, it is just intended to hold some basic text.

If floating elements are added, the parent container does not get wrapped around those elements because the height of floating elements is not inherited by the parent container.

So for panel-header & panel-footer, clearfix is needed to clear the float layout of elements: Clearfix class gives a visual appearance that the height of the parent container has been increased to accommodate all of its child elements.

 <div class="container">
    <div class="panel panel-default">
        <div class="panel-footer">
            <div class="col-xs-6">
                <input type="button" class="btn btn-primary"   value="Button1">
                <input type="button" class="btn btn-primary"   value="Button2">
                <input type="button" class="btn btn-primary"   value="Button3">
            </div>
        </div>
    </div>

    <div class="panel panel-default">
        <div class="panel-footer">
            <div class="col-xs-6">
                <input type="button" class="btn btn-primary"   value="Button1">
                <input type="button" class="btn btn-primary"   value="Button2">
                <input type="button" class="btn btn-primary"   value="Button3">
            </div>
            <div class="clearfix"/>
        </div>
    </div>
</div>

see an example photo here

jQuery / Javascript code check, if not undefined

I generally like the shorthand version:

if (!!wlocation) { window.location = wlocation; }

Pseudo-terminal will not be allocated because stdin is not a terminal

Try ssh -t -t(or ssh -tt for short) to force pseudo-tty allocation even if stdin isn't a terminal.

See also: Terminating SSH session executed by bash script

From ssh manpage:

-T      Disable pseudo-tty allocation.

-t      Force pseudo-tty allocation.  This can be used to execute arbitrary 
        screen-based programs on a remote machine, which can be very useful,
        e.g. when implementing menu services.  Multiple -t options force tty
        allocation, even if ssh has no local tty.

How can I remove leading and trailing quotes in SQL Server?

You can use following query which worked for me-

For updating-

UPDATE table SET colName= REPLACE(LTRIM(RTRIM(REPLACE(colName, '"', ''))), '', '"') WHERE...

For selecting-

SELECT REPLACE(LTRIM(RTRIM(REPLACE(colName, '"', ''))), '', '"') FROM TableName

Parsing command-line arguments in C

Try CLPP library. It's simple and flexible library for command line parameters parsing. Header-only and cross-platform. Uses ISO C++ and Boost C++ libraries only. IMHO it is easier than Boost.Program_options.

Library: http://sourceforge.net/projects/clp-parser/

26 October 2010 - new release 2.0rc. Many bugs fixed, full refactoring of the source code, documentation, examples and comments have been corrected.

How do I move a redis database from one server to another?

you can also use rdd

it can dump & restore a running redis server and allow filter/match/rename dumps keys

Is there a vr (vertical rule) in html?

There isn't, where would it go?

Use CSS to put a border-right on an element if you want something like that.

How can I send JSON response in symfony2 controller

Since Symfony 3.1 you can use JSON Helper http://symfony.com/doc/current/book/controller.html#json-helper

public function indexAction()
{
// returns '{"username":"jane.doe"}' and sets the proper Content-Type header
return $this->json(array('username' => 'jane.doe'));

// the shortcut defines three optional arguments
// return $this->json($data, $status = 200, $headers = array(), $context = array());
}

JQuery get data from JSON array

try this

$.getJSON(url, function(data){
    $.each(data.response.venue.tips.groups.items, function (index, value) {
        console.log(this.text);
    });
});

adding x and y axis labels in ggplot2

since the data ex1221new was not given, so I have created a dummy data and added it to a data frame. Also, the question which was asked has few changes in codes like then ggplot package has deprecated the use of

"scale_area()" and nows uses scale_size_area()
"opts()" has changed to theme()

In my answer,I have stored the plot in mygraph variable and then I have used

mygraph$labels$x="Discharge of materials" #changes x axis title
       mygraph$labels$y="Area Affected" # changes y axis title

And the work is done. Below is the complete answer.

install.packages("Sleuth2")
library(Sleuth2)
library(ggplot2)

ex1221new<-data.frame(Discharge<-c(100:109),Area<-c(120:129),NO3<-seq(2,5,length.out = 10))
discharge<-ex1221new$Discharge
area<-ex1221new$Area
nitrogen<-ex1221new$NO3
p <- ggplot(ex1221new, aes(discharge, area), main="Point")
mygraph<-p + geom_point(aes(size= nitrogen)) + 
  scale_size_area() + ggtitle("Weighted Scatterplot of Watershed Area vs. Discharge and Nitrogen Levels (PPM)")+
theme(
 plot.title =  element_text(color="Blue", size=30, hjust = 0.5), 

 # change the styling of both the axis simultaneously from this-
 axis.title = element_text(color = "Green", size = 20, family="Courier",)
 

   # you can change the  axis title from the code below
   mygraph$labels$x="Discharge of materials" #changes x axis title
   mygraph$labels$y="Area Affected" # changes y axis title
   mygraph



   

Also, you can change the labels title from the same formula used above -

mygraph$labels$size= "N2" #size contains the nitrogen level 

java.io.IOException: Broken pipe

You may have not set the output file.

Visual Studio 2017 errors on standard headers

If the problem is not solved by above answer, check whether the Windows SDK version is 10.0.15063.0.

Project -> Properties -> General -> Windows SDK Version -> select 10.0.15063.0

After this rebuild the solution.  

Access 2010 VBA query a table and iterate through results

DAO is native to Access and by far the best for general use. ADO has its place, but it is unlikely that this is it.

 Dim rs As DAO.Recordset
 Dim db As Database
 Dim strSQL as String

 Set db=CurrentDB

 strSQL = "select * from table where some condition"

 Set rs = db.OpenRecordset(strSQL)

 Do While Not rs.EOF

    rs.Edit
    rs!SomeField = "Abc"
    rs!OtherField = 2
    rs!ADate = Date()
    rs.Update

    rs.MoveNext
Loop

String contains another string

You can use .indexOf():

if(str.indexOf(substr) > -1) {

}

C# RSA encryption/decryption with transmission

well there are really enough examples for this, but anyway, here you go

using System;
using System.Security.Cryptography;

namespace RsaCryptoExample
{
  static class Program
  {
    static void Main()
    {
      //lets take a new CSP with a new 2048 bit rsa key pair
      var csp = new RSACryptoServiceProvider(2048);

      //how to get the private key
      var privKey = csp.ExportParameters(true);

      //and the public key ...
      var pubKey = csp.ExportParameters(false);

      //converting the public key into a string representation
      string pubKeyString;
      {
        //we need some buffer
        var sw = new System.IO.StringWriter();
        //we need a serializer
        var xs = new System.Xml.Serialization.XmlSerializer(typeof(RSAParameters));
        //serialize the key into the stream
        xs.Serialize(sw, pubKey);
        //get the string from the stream
        pubKeyString = sw.ToString();
      }

      //converting it back
      {
        //get a stream from the string
        var sr = new System.IO.StringReader(pubKeyString);
        //we need a deserializer
        var xs = new System.Xml.Serialization.XmlSerializer(typeof(RSAParameters));
        //get the object back from the stream
        pubKey = (RSAParameters)xs.Deserialize(sr);
      }

      //conversion for the private key is no black magic either ... omitted

      //we have a public key ... let's get a new csp and load that key
      csp = new RSACryptoServiceProvider();
      csp.ImportParameters(pubKey);

      //we need some data to encrypt
      var plainTextData = "foobar";

      //for encryption, always handle bytes...
      var bytesPlainTextData = System.Text.Encoding.Unicode.GetBytes(plainTextData);

      //apply pkcs#1.5 padding and encrypt our data 
      var bytesCypherText = csp.Encrypt(bytesPlainTextData, false);

      //we might want a string representation of our cypher text... base64 will do
      var cypherText = Convert.ToBase64String(bytesCypherText);


      /*
       * some transmission / storage / retrieval
       * 
       * and we want to decrypt our cypherText
       */

      //first, get our bytes back from the base64 string ...
      bytesCypherText = Convert.FromBase64String(cypherText);

      //we want to decrypt, therefore we need a csp and load our private key
      csp = new RSACryptoServiceProvider();
      csp.ImportParameters(privKey);

      //decrypt and strip pkcs#1.5 padding
      bytesPlainTextData = csp.Decrypt(bytesCypherText, false);

      //get our original plainText back...
      plainTextData = System.Text.Encoding.Unicode.GetString(bytesPlainTextData);
    }
  }
}

as a side note: the calls to Encrypt() and Decrypt() have a bool parameter that switches between OAEP and PKCS#1.5 padding ... you might want to choose OAEP if it's available in your situation

How to add a class with React.js?

Taken from their site.

render() {
  let className = 'menu';
  if (this.props.isActive) {
    className += ' menu-active';
  }
  return <span className={className}>Menu</span>
}

https://reactjs.org/docs/faq-styling.html

Maximum length for MySQL type text

Type       | Approx. Length     | Exact Max. Length Allowed
-----------------------------------------------------------
TINYTEXT   | 256 Bytes          |           255 characters
TEXT       |  64 Kilobytes      |        65,535 characters
MEDIUMTEXT |  16 Megabytes      |    16,777,215 characters
LONGTEXT   |   4 Gigabytes      | 4,294,967,295 characters

Basically, it's like:

"Exact Max. Length Allowed" = "Approx. Length" in bytes - 1

Note: If using multibyte characters (like Arabic, where each Arabic character takes 2 bytes), the column "Exact Max. Length Allowed" for TINYTEXT can hold be up to 127 Arabic characters (Note: space, dash, underscore, and other such characters, are 1-byte characters).

How to dynamically add a style for text-align using jQuery

You could also try the following to add an inline style to the element:

$(this).attr('style', 'text-align: center');

This should make sure that other styling rules aren't overriding what you thought would work. I believe inline styles usually get precedence.

EDIT: Also, another tool that may help you is Jash (http://www.billyreisinger.com/jash/). It gives you a javascript command prompt so you can ensure you easily test javascript statements and make sure you're selecting the right element, etc.

Why does JSON.parse fail with the empty string?

As an empty string is not valid JSON it would be incorrect for JSON.parse('') to return null because "null" is valid JSON. e.g.

JSON.parse("null");

returns null. It would be a mistake for invalid JSON to also be parsed to null.

While an empty string is not valid JSON two quotes is valid JSON. This is an important distinction.

Which is to say a string that contains two quotes is not the same thing as an empty string.

JSON.parse('""');

will parse correctly, (returning an empty string). But

JSON.parse('');

will not.

Valid minimal JSON strings are

The empty object '{}'

The empty array '[]'

The string that is empty '""'

A number e.g. '123.4'

The boolean value true 'true'

The boolean value false 'false'

The null value 'null'

How to ignore PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException?

Set validateTLSCertificates property to false for your JSoup command.

Jsoup.connect("https://google.com/").validateTLSCertificates(false).get();

Difference between Build Solution, Rebuild Solution, and Clean Solution in Visual Studio?

All I know is a Clean does not do what "make clean" used to do - if I Clean a solution I would expect it delete obj and bin files/folders such that it builds like is was a fresh checkout of the source. In my experience though I often find times where a Clean and Build or Rebuild still produces strange errors on source that is known to compile and what is required is a manual deletion of the bin/obj folders, then it will build.

is there a css hack for safari only NOT chrome?

It working 100% in safari..i tried

@media screen and (-webkit-min-device-pixel-ratio:0) 
{
::i-block-chrome, Class Name {your styles}
}

Height equal to dynamic width (CSS fluid layout)

It is possible without any Javascript :)

The HTML:

<div class='box'>
    <div class='content'>Aspect ratio of 1:1</div>
</div> 

The CSS:

.box {
    position: relative;
    width:    50%; /* desired width */
}

.box:before {
    content:     "";
    display:     block;
    padding-top: 100%; /* initial ratio of 1:1*/
}

.content {
    position: absolute;
    top:      0;
    left:     0;
    bottom:   0;
    right:    0;
}

/* Other ratios - just apply the desired class to the "box" element */
.ratio2_1:before{
    padding-top: 50%;
}
.ratio1_2:before{
    padding-top: 200%;
}
.ratio4_3:before{
    padding-top: 75%;
}
.ratio16_9:before{
    padding-top: 56.25%;
}

How to identify platform/compiler from preprocessor macros?

For Mac OS:

#ifdef __APPLE__

For MingW on Windows:

#ifdef __MINGW32__

For Linux:

#ifdef __linux__

For other Windows compilers, check this thread and this for several other compilers and architectures.

Passing event and argument to v-on in Vue.js

Depending on what arguments you need to pass, especially for custom event handlers, you can do something like this:

<div @customEvent='(arg1) => myCallback(arg1, arg2)'>Hello!</div>

Add my custom http header to Spring RestTemplate request / extend RestTemplate

You can pass custom http headers with RestTemplate exchange method as below.

HttpHeaders headers = new HttpHeaders();
headers.setAccept(Arrays.asList(new MediaType[] { MediaType.APPLICATION_JSON }));
headers.setContentType(MediaType.APPLICATION_JSON);
headers.set("X-TP-DeviceID", "your value");

HttpEntity<RestRequest> entityReq = new HttpEntity<RestRequest>(request, headers);

RestTemplate template = new RestTemplate();

ResponseEntity<RestResponse> respEntity = template
    .exchange("RestSvcUrl", HttpMethod.POST, entityReq, RestResponse.class);

EDIT : Below is the updated code. This link has several ways of calling rest service with examples

RestTemplate restTemplate = new RestTemplate();

HttpHeaders headers = new HttpHeaders();
headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
headers.setContentType(MediaType.APPLICATION_JSON);
headers.set("X-TP-DeviceID", "your value");

HttpEntity<String> entity = new HttpEntity<String>("parameters", headers);

ResponseEntity<Mall[]> respEntity = restTemplate.exchange(url, HttpMethod.POST, entity, Mall[].class);

Mall[] resp = respEntity.getBody();

How to use a calculated column to calculate another column in the same view

If you want to refer to calculated column on the "same query level" then you could use CROSS APPLY(Oracle 12c):

--Sample data:
CREATE TABLE tab(ColumnA NUMBER(10,2),ColumnB NUMBER(10,2),ColumnC NUMBER(10,2));

INSERT INTO tab(ColumnA, ColumnB, ColumnC) VALUES (2, 10, 2);
INSERT INTO tab(ColumnA, ColumnB, ColumnC) VALUES (3, 15, 6);
INSERT INTO tab(ColumnA, ColumnB, ColumnC) VALUES (7, 14, 3);
COMMIT;

Query:

SELECT
  ColumnA,
  ColumnB,
  sub.calccolumn1,
  sub.calccolumn1 / ColumnC AS calccolumn2
FROM tab t
CROSS APPLY (SELECT t.ColumnA + t.ColumnB AS calccolumn1 FROM dual) sub;

DBFiddle Demo


Please note that expression from CROSS APPLY/OUTER APPLY is available in other clauses too:

SELECT
  ColumnA,
  ColumnB,
  sub.calccolumn1,
  sub.calccolumn1 / ColumnC AS calccolumn2
FROM tab t
CROSS APPLY (SELECT t.ColumnA + t.ColumnB AS calccolumn1 FROM dual) sub
WHERE sub.calccolumn1 = 12;
-- GROUP BY ...
-- ORDER BY ...;

This approach allows to avoid wrapping entire query with outerquery or copy/paste same expression in multiple places(with complex one it could be hard to maintain).

Related article: The SQL Language’s Most Missing Feature

Scala best way of turning a Collection into a Map-by-key?

Scala 2.13+

instead of "breakOut"

c.map(t => (t.getP, t)).to(Mat)

Scroll to "View": https://www.scala-lang.org/blog/2017/02/28/collections-rework.html

python requests file upload

If upload_file is meant to be the file, use:

files = {'upload_file': open('file.txt','rb')}
values = {'DB': 'photcat', 'OUT': 'csv', 'SHORT': 'short'}

r = requests.post(url, files=files, data=values)

and requests will send a multi-part form POST body with the upload_file field set to the contents of the file.txt file.

The filename will be included in the mime header for the specific field:

>>> import requests
>>> open('file.txt', 'wb')  # create an empty demo file
<_io.BufferedWriter name='file.txt'>
>>> files = {'upload_file': open('file.txt', 'rb')}
>>> print(requests.Request('POST', 'http://example.com', files=files).prepare().body.decode('ascii'))
--c226ce13d09842658ffbd31e0563c6bd
Content-Disposition: form-data; name="upload_file"; filename="file.txt"


--c226ce13d09842658ffbd31e0563c6bd--

Note the filename="file.txt" parameter.

You can use a tuple for the files mapping value, with between 2 and 4 elements, if you need more control. The first element is the filename, followed by the contents, and an optional content-type header value and an optional mapping of additional headers:

files = {'upload_file': ('foobar.txt', open('file.txt','rb'), 'text/x-spam')}

This sets an alternative filename and content type, leaving out the optional headers.

If you are meaning the whole POST body to be taken from a file (with no other fields specified), then don't use the files parameter, just post the file directly as data. You then may want to set a Content-Type header too, as none will be set otherwise. See Python requests - POST data from a file.

Difference between Visual Basic 6.0 and VBA

VBA stands for Visual Basic for Applications and so is the small "for applications" scripting brother of VB. VBA is indeed available in Excel, but also in the other office applications.

With VB, one can create a stand-alone windows application, which is not possible with VBA.

It is possible for developers however to "embed" VBA in their own applications, as a scripting language to automate those applications.

Edit: From the VBA FAQ:

Q. What is Visual Basic for Applications?

A. Microsoft Visual Basic for Applications (VBA) is an embeddable programming environment designed to enable developers to build custom solutions using the full power of Microsoft Visual Basic. Developers using applications that host VBA can automate and extend the application functionality, shortening the development cycle of custom business solutions.

Note that VB.NET is even another language, which only shares syntax with VB.

Anchor links in Angularjs?

Works for me:

 <a onclick='return false;' href="" class="collapsed" role="button" data-toggle="collapse" data-parent="#accordion" ng-href="#profile#collapse{{$index}}"> blalba </a>

How to get Top 5 records in SqLite?

select price from mobile_sales_details order by price desc limit 5

Note: i have mobile_sales_details table

syntax

select column_name from table_name order by column_name desc limit size.  

if you need top low price just remove the keyword desc from order by

In Powershell what is the idiomatic way of converting a string to an int?

You can use the -as operator. If casting succeed you get back a number:

$numberAsString -as [int]

What is the difference between onBlur and onChange attribute in HTML?

I think it's important to note here that onBlur() fires regardless.

This is a helpful thread but the only thing it doesn't clarify is that onBlur() will fire every single time.

onChange() will only fire when the value is changed.

How to bind multiple values to a single WPF TextBlock?

You can use a MultiBinding combined with the StringFormat property. Usage would resemble the following:

<TextBlock>
    <TextBlock.Text>    
        <MultiBinding StringFormat="{}{0} + {1}">
            <Binding Path="Name" />
            <Binding Path="ID" />
        </MultiBinding>
    </TextBlock.Text>
</TextBlock>

Giving Name a value of Foo and ID a value of 1, your output in the TextBlock would then be Foo + 1.

Note: that this is only supported in .NET 3.5 SP1 and 3.0 SP2 or later.

HTML Script tag: type or language (or omit both)?

HTML4/XHTML1 requires

<script type="...">...</script>

HTML5 faces the fact that there is only one scripting language on the web, and allows

<script>...</script>

The latter works in any browser that supports scripting (NN2+).

Return array from function

neater:

function BlockID() {
  return {
    "s":"Images/Block_01.png",
    "g":"Images/Block_02.png",
    "C":"Images/Block_03.png",
    "d":"Images/Block_04.png"
   }
}

or just

var images = {
  "s":"Images/Block_01.png",
  "g":"Images/Block_02.png",
  "C":"Images/Block_03.png",
  "d":"Images/Block_04.png"
}

HTML Input="file" Accept Attribute File Type (CSV)

After my test, on ?macOS 10.15.7 Catalina?, the answer of ?Dom / Rikin Patel? cannot recognize the [.xlsx] file normally.

I personally summarized the practice of most of the existing answers and passed personal tests. Sum up the following answers:

accept=".csv, .xls, .xlsx, text/csv, application/csv,
text/comma-separated-values, application/csv, application/excel,
application/vnd.msexcel, text/anytext, application/vnd. ms-excel,
application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"

Get element type with jQuery

Use Nodename over tagName :

nodeName contains all functionalities of tagName, plus a few more. Therefore nodeName is always the better choice.

see DOM Core

How do I stop a program when an exception is raised in Python?

import sys

try:
    import feedparser
except:
    print "Error: Cannot import feedparser.\n" 
    sys.exit(1)

Here we're exiting with a status code of 1. It is usually also helpful to output an error message, write to a log, and clean up.

Changing the row height of a datagridview

You also need to change the resizable property to true

    dataGridView1.RowTemplate.Resizable = DataGridViewTriState.True;
    dataGridView1.RowTemplate.Height = 50;

Python append() vs. + operator on lists, why do these give different results?

append is appending an element to a list. if you want to extend the list with the new list you need to use extend.

>>> c = [1, 2, 3]
>>> c.extend(c)
>>> c
[1, 2, 3, 1, 2, 3]

Accessing a resource via codebehind in WPF

You may also use this.Resources["mykey"]. I guess that is not much better than your own suggestion.

Convert Base64 string to an image file?

That's an old thread, but in case you want to upload the image having same extension-

    $image = $request->image;
    $imageInfo = explode(";base64,", $image);
    $imgExt = str_replace('data:image/', '', $imageInfo[0]);      
    $image = str_replace(' ', '+', $imageInfo[1]);
    $imageName = "post-".time().".".$imgExt;
    Storage::disk('public_feeds')->put($imageName, base64_decode($image));

You can create 'public_feeds' in laravel's filesystem.php-

   'public_feeds' => [
        'driver' => 'local',
        'root'   => public_path() . '/uploads/feeds',
    ],

How to print environment variables to the console in PowerShell?

The following is works best in my opinion:

Get-Item Env:PATH
  1. It's shorter and therefore a little bit easier to remember than Get-ChildItem. There's no hierarchy with environment variables.
  2. The command is symmetrical to one of the ways that's used for setting environment variables with Powershell. (EX: Set-Item -Path env:SomeVariable -Value "Some Value")
  3. If you get in the habit of doing it this way you'll remember how to list all Environment variables; simply omit the entry portion. (EX: Get-Item Env:)

I found the syntax odd at first, but things started making more sense after I understood the notion of Providers. Essentially PowerShell let's you navigate disparate components of the system in a way that's analogous to a file system.

What's the point of the trailing colon in Env:? Try listing all of the "drives" available through Providers like this:

PS> Get-PSDrive

I only see a few results... (Alias, C, Cert, D, Env, Function, HKCU, HKLM, Variable, WSMan). It becomes obvious that Env is simply another "drive" and the colon is a familiar syntax to anyone who's worked in Windows.

You can navigate the drives and pick out specific values:

Get-ChildItem C:\Windows
Get-Item C:
Get-Item Env:
Get-Item HKLM:
Get-ChildItem HKLM:SYSTEM

Alter table to modify default value of column

ALTER TABLE {TABLE NAME}
ALTER COLUMN {COLUMN NAME} SET DEFAULT '{DEFAULT VALUES}'

example :

ALTER TABLE RESULT
ALTER COLUMN STATUS SET DEFAULT 'FAIL'

Chrome refuses to execute an AJAX script due to wrong MIME type

FYI, I've got the same error from Chrome console. I thought my AJAX function causing it, but I uncommented my minified script from /javascripts/ajax-vanilla.min.js to /javascripts/ajax-vanilla.js. But in reality the source file was at /javascripts/src/ajax-vanilla.js. So in Chrome you getting bad MIME type error even if the file cannot be found. In this case, the error message is described as text/plain bad MIME type.

href="file://" doesn't work

%20 is the space between AmberCRO SOP.

Try -

href="http://file:///K:/AmberCRO SOP/2011-07-05/SOP-SOP-3.0.pdf"

Or rename the folder as AmberCRO-SOP and write it as -

href="http://file:///K:/AmberCRO-SOP/2011-07-05/SOP-SOP-3.0.pdf"

What's the "average" requests per second for a production web application?

OpenStreetMap seems to have 10-20 per second

Wikipedia seems to be 30000 to 70000 per second spread over 300 servers (100 to 200 requests per second per machine, most of which is caches)

Geograph is getting 7000 images per week (1 upload per 95 seconds)

show all tags in git log

Note about tag of tag (tagging a tag), which is at the origin of your issue, as Charles Bailey correctly pointed out in the comment:

Make sure you study this thread, as overriding a signed tag is not as easy:

  • if you already pushed a tag, the git tag man page seriously advised against a simple git tag -f B to replace a tag name "A"
  • don't try to recreate a signed tag with git tag -f (see the thread extract below)

    (it is about a corner case, but quite instructive about tags in general, and it comes from another SO contributor Jakub Narebski):

Please note that the name of tag (heavyweight tag, i.e. tag object) is stored in two places:

  • in the tag object itself as a contents of 'tag' header (you can see it in output of "git show <tag>" and also in output of "git cat-file -p <tag>", where <tag> is heavyweight tag, e.g. v1.6.3 in git.git repository),
  • and also is default name of tag reference (reference in "refs/tags/*" namespace) pointing to a tag object.
    Note that the tag reference (appropriate reference in the "refs/tags/*" namespace) is purely local matter; what one repository has in 'refs/tags/v0.1.3', other can have in 'refs/tags/sub/v0.1.3' for example.

So when you create signed tag 'A', you have the following situation (assuming that it points at some commit)

  35805ce   <--- 5b7b4ead  <=== refs/tags/A
  (commit)       tag A
                 (tag)

Please also note that "git tag -f A A" (notice the absence of options forcing it to be an annotated tag) is a noop - it doesn't change the situation.

If you do "git tag -f -s A A": note that you force owerwriting a tag (so git assumes that you know what you are doing), and that one of -s / -a / -m options is used to force annotated tag (creation of tag object), you will get the following situation

  35805ce   <--- 5b7b4ea  <--- ada8ddc  <=== refs/tags/A
  (commit)       tag A         tag A
                 (tag)         (tag)

Note also that "git show A" would show the whole chain down to the non-tag object...

Create stacked barplot where each stack is scaled to sum to 100%

Chris Beeley is rigth, you only need the proportions by column. Using your data is:

 your_matrix<-( 
               rbind(
                       c(23,234,324), 
                       c(34,534,12), 
                       c(56,324,124), 
                       c(34,234,124),
                       c(123,534,654)
                    )
                )

 barplot(prop.table(your_matrix, 2) )

Gives:

enter image description here

How to check whether particular port is open or closed on UNIX?

Try (maybe as root)

lsof -i -P

and grep the output for the port you are looking for.

For example to check for port 80 do

lsof -i -P | grep :80

Command output redirect to file and terminal

In case somebody needs to append the output and not overriding, it is possible to use "-a" or "--append" option of "tee" command :

ls 2>&1 | tee -a /tmp/ls.txt
ls 2>&1 | tee --append /tmp/ls.txt

What's the difference between getRequestURI and getPathInfo methods in HttpServletRequest?

Let's break down the full URL that a client would type into their address bar to reach your servlet:

http://www.example.com:80/awesome-application/path/to/servlet/path/info?a=1&b=2#boo

The parts are:

  1. scheme: http
  2. hostname: www.example.com
  3. port: 80
  4. context path: awesome-application
  5. servlet path: path/to/servlet
  6. path info: path/info
  7. query: a=1&b=2
  8. fragment: boo

The request URI (returned by getRequestURI) corresponds to parts 4, 5 and 6.

(incidentally, even though you're not asking for this, the method getRequestURL would give you parts 1, 2, 3, 4, 5 and 6).

Now:

  • part 4 (the context path) is used to select your particular application out of many other applications that may be running in the server
  • part 5 (the servlet path) is used to select a particular servlet out of many other servlets that may be bundled in your application's WAR
  • part 6 (the path info) is interpreted by your servlet's logic (e.g. it may point to some resource controlled by your servlet).
  • part 7 (the query) is also made available to your servlet using getQueryString
  • part 8 (the fragment) is not even sent to the server and is relevant and known only to the client

The following always holds (except for URL encoding differences):

requestURI = contextPath + servletPath + pathInfo

The following example from the Servlet 3.0 specification is very helpful:


Note: image follows, I don't have the time to recreate in HTML:

enter image description here

App installation failed due to application-identifier entitlement

I solved this without deleting the app

With the project open in xcode. Project -> Build Settings -> Code Signing -> Provisioning Profiles (drop down) It is probably set to automatic and is choosing the wrong profile. Open the drop down and choose the correct one, then re-run the app.

New to unit testing, how to write great tests?

Try writing a Unit Test before writing the method it is going to test.

That will definitely force you to think a little differently about how things are being done. You'll have no idea how the method is going to work, just what it is supposed to do.

You should always be testing the results of the method, not how the method gets those results.

Changing CSS for last <li>

2015 Answer: CSS last-of-type allows you to style the last item.

ul li:last-of-type { color: red; }

Table fixed header and scrollable body

In my eyes, one of the best plugins for jQuery is DataTables.

It also has an extension for fixed header, and it is very easily implemented.

Taken from their site:

HTML:

<table id="example" class="display" cellspacing="0" width="100%">
    <thead>
        <tr>
            <th>Name</th>
            <th>Position</th>
            <th>Office</th>
            <th>Age</th>
            <th>Start date</th>
            <th>Salary</th>
        </tr>
    </thead>

    <tfoot>
        <tr>
            <th>Name</th>
            <th>Position</th>
            <th>Office</th>
            <th>Age</th>
            <th>Start date</th>
            <th>Salary</th>
        </tr>
    </tfoot>

    <tbody>
        <tr>
            <td>Tiger Nixon</td>
            <td>System Architect</td>
            <td>Edinburgh</td>
            <td>61</td>
            <td>2011/04/25</td>
            <td>$320,800</td>
        </tr>
        <tr>
            <td>Garrett Winters</td>
            <td>Accountant</td>
            <td>Tokyo</td>
            <td>63</td>
            <td>2011/07/25</td>
            <td>$170,750</td>
        </tr>
        <tr>
            <td>Ashton Cox</td>
            <td>Junior Technical Author</td>
            <td>San Francisco</td>
            <td>66</td>
            <td>2009/01/12</td>
            <td>$86,000</td>
        </tr>
  </tbody>
</table>

JavaScript:

$(document).ready(function() {
    var table = $('#example').DataTable();

    new $.fn.dataTable.FixedHeader( table );
} );

But the simplest you can have for just making a scrollable <tbody> is:

//configure table with fixed header and scrolling rows
$('#example').DataTable({
    scrollY: 400,
    scrollCollapse: true,
    paging: false,
    searching: false,
    ordering: false,
    info: false
});

Parse JSON with R

Here is the missing example

library(rjson)
url <- 'http://someurl/data.json'
document <- fromJSON(file=url, method='C')

Text not wrapping in p tag

add float: left property to the image.

#rb-menu-com li .submenu div img {
    border:1px solid #fff;
    float:left;
}

What's the difference between Sender, From and Return-Path?

The official RFC which defines this specification could be found here:

http://tools.ietf.org/html/rfc4021#section-2.1.2 (look at paragraph 2.1.2. and the following)

2.1.2. Header Field: From

Description:  
    Mailbox of message author  
[...]  
Related information:
    Specifies the author(s) of the message; that is, the mailbox(es)
    of the person(s) or system(s) responsible for the writing of the
    message. Defined as standard by RFC 822.

2.1.3. Header Field: Sender

Description:  
    Mailbox of message sender  
[...]  
Related information:
    Specifies the mailbox of the agent responsible for the actual
    transmission of the message.  Defined as standard by RFC 822.

2.1.22. Header Field: Return-Path

Description:
    Message return path
[...]  
Related information:
    Return path for message response diagnostics. See also RFC 2821
    [17]. Defined as standard by RFC 822.

Using global variables in a function

Python uses a simple heuristic to decide which scope it should load a variable from, between local and global. If a variable name appears on the left hand side of an assignment, but is not declared global, it is assumed to be local. If it does not appear on the left hand side of an assignment, it is assumed to be global.

>>> import dis
>>> def foo():
...     global bar
...     baz = 5
...     print bar
...     print baz
...     print quux
... 
>>> dis.disassemble(foo.func_code)
  3           0 LOAD_CONST               1 (5)
              3 STORE_FAST               0 (baz)

  4           6 LOAD_GLOBAL              0 (bar)
              9 PRINT_ITEM          
             10 PRINT_NEWLINE       

  5          11 LOAD_FAST                0 (baz)
             14 PRINT_ITEM          
             15 PRINT_NEWLINE       

  6          16 LOAD_GLOBAL              1 (quux)
             19 PRINT_ITEM          
             20 PRINT_NEWLINE       
             21 LOAD_CONST               0 (None)
             24 RETURN_VALUE        
>>> 

See how baz, which appears on the left side of an assignment in foo(), is the only LOAD_FAST variable.

How to convert milliseconds into human readable form?

This is a solution. Later you can split by ":" and take the values of the array

/**
 * Converts milliseconds to human readeable language separated by ":"
 * Example: 190980000 --> 2:05:3 --> 2days 5hours 3min
 */
function dhm(t){
    var cd = 24 * 60 * 60 * 1000,
        ch = 60 * 60 * 1000,
        d = Math.floor(t / cd),
        h = '0' + Math.floor( (t - d * cd) / ch),
        m = '0' + Math.round( (t - d * cd - h * ch) / 60000);
    return [d, h.substr(-2), m.substr(-2)].join(':');
}

var delay = 190980000;                   
var fullTime = dhm(delay);
console.log(fullTime);

How to remove the URL from the printing page?

Browser issue but can be solved by these:

<style type="text/css" media="print">
      @media print
      {
         @page {
           margin-top: 0;
           margin-bottom: 0;
         }
         body  {
           padding-top: 72px;
           padding-bottom: 72px ;
         }
      } 
</style>

react-router scroll to top on every transition

Here is another method.

For react-router v4 you can also bind a listener to change in history event, in the following manner:

let firstMount = true;
const App = (props) => {
    if (typeof window != 'undefined') { //incase you have server-side rendering too             
        firstMount && props.history.listen((location, action) => {
            setImmediate(() => window.scrollTo(0, 0)); // ive explained why i used setImmediate below
        });
        firstMount = false;
    }

    return (
        <div>
            <MyHeader/>            
            <Switch>                            
                <Route path='/' exact={true} component={IndexPage} />
                <Route path='/other' component={OtherPage} />
                // ...
             </Switch>                        
            <MyFooter/>
        </div>
    );
}

//mounting app:
render((<BrowserRouter><Route component={App} /></BrowserRouter>), document.getElementById('root'));

The scroll level will be set to 0 without setImmediate() too if the route is changed by clicking on a link but if user presses back button on browser then it will not work as browser reset the scroll level manually to the previous level when the back button is pressed, so by using setImmediate() we cause our function to be executed after browser is finished resetting the scroll level thus giving us the desired effect.

Resolve Javascript Promise outside function scope

simple:

var promiseResolve, promiseReject;

var promise = new Promise(function(resolve, reject){
  promiseResolve = resolve;
  promiseReject = reject;
});

promiseResolve();

How to get Android crash logs?

Here is another solution for Crash Log.

Android market has tool named "Crash Collector"

check following link for more information

http://kpbird.blogspot.com/2011/08/android-application-crash-logs.html

How to create exe of a console application

For .NET Core 2.2 you can publish the application and set the target to be a self-contained executable.

In Visual Studio right click your console application project. Select publish to folder and set the profile settings like so:

Visual Studio Publish Menu

You'll find your compiled code with the .exe in the publish folder.

Get The Current Domain Name With Javascript (Not the path, etc.)

If you wish a full domain origin, you can use this:

document.location.origin

And if you wish to get only the domain, use can you just this:

document.location.hostname

But you have other options, take a look at the properties in:

document.location

Disabling the button after once click

think simple

<button id="button1" onclick="Click();">ok</button>
<script>
    var buttonClick = false;
    function Click() {
        if (buttonClick) {
            return;
        }
        else {
            buttonClick = true;
            //todo
            alert("ok");
            //buttonClick = false;
        }
    }
</script>

if you want run once :)

Rails Object to hash

Swanand's answer is great.

if you are using FactoryGirl, you can use its build method to generate the attribute hash without the key id. e.g.

build(:post).attributes

How can I assign an ID to a view programmatically?

Yes, you can call setId(value) in any view with any (positive) integer value that you like and then find it in the parent container using findViewById(value). Note that it is valid to call setId() with the same value for different sibling views, but findViewById() will return only the first one.

XSLT getting last element

You need to put the last() indexing on the nodelist result, rather than as part of the selection criteria. Try:

(//element[@name='D'])[last()]

HttpURLConnection timeout settings

HttpURLConnection has a setConnectTimeout method.

Just set the timeout to 5000 milliseconds, and then catch java.net.SocketTimeoutException

Your code should look something like this:


try {
   HttpURLConnection.setFollowRedirects(false);
   HttpURLConnection con = (HttpURLConnection) new URL(url).openConnection();
   con.setRequestMethod("HEAD");

   con.setConnectTimeout(5000); //set timeout to 5 seconds

   return (con.getResponseCode() == HttpURLConnection.HTTP_OK);
} catch (java.net.SocketTimeoutException e) {
   return false;
} catch (java.io.IOException e) {
   return false;
}


How do I edit an incorrect commit message in git ( that I've pushed )?

The message from Linus Torvalds may answer your question:

Modify/edit old commit messages

Short answer: you can not (if pushed).


extract (Linus refers to BitKeeper as BK):

Side note, just out of historical interest: in BK you could.

And if you're used to it (like I was) it was really quite practical. I would apply a patch-bomb from Andrew, notice something was wrong, and just edit it before pushing it out.

I could have done the same with git. It would have been easy enough to make just the commit message not be part of the name, and still guarantee that the history was untouched, and allow the "fix up comments later" thing.

But I didn't.

Part of it is purely "internal consistency". Git is simply a cleaner system thanks to everything being SHA1-protected, and all objects being treated the same, regardless of object type. Yeah, there are four different kinds of objects, and they are all really different, and they can't be used in the same way, but at the same time, even if their encoding might be different on disk, conceptually they all work exactly the same.

But internal consistency isn't really an excuse for being inflexible, and clearly it would be very flexible if we could just fix up mistakes after they happen. So that's not a really strong argument.

The real reason git doesn't allow you to change the commit message ends up being very simple: that way, you can trust the messages. If you allowed people to change them afterwards, the messages are inherently not very trustworthy.


To be complete, you could rewrite your local commit history in order to reflect what you want, as suggested by sykora (with some rebase and reset --hard, gasp!)

However, once you publish your revised history again (with a git push origin +master:master, the + sign forcing the push to occur, even if it doesn't result in a "fast-forward" commit)... you might get into some trouble.

Extract from this other SO question:

I actually once pushed with --force to git.git repository and got scolded by Linus BIG TIME. It will create a lot of problems for other people. A simple answer is "don't do it".

Loop through files in a folder using VBA?

Try this one. (LINK)

Private Sub CommandButton3_Click()

Dim FileExtStr As String
Dim FileFormatNum As Long
Dim xWs As Worksheet
Dim xWb As Workbook
Dim FolderName As String
Application.ScreenUpdating = False
Set xWb = Application.ThisWorkbook
DateString = Format(Now, "yyyy-mm-dd hh-mm-ss")
FolderName = xWb.Path & "\" & xWb.Name & " " & DateString
MkDir FolderName
For Each xWs In xWb.Worksheets
    xWs.Copy
    If Val(Application.Version) < 12 Then
        FileExtStr = ".xls": FileFormatNum = -4143
    Else
        Select Case xWb.FileFormat
            Case 51:
                FileExtStr = ".xlsx": FileFormatNum = 51
            Case 52:
                If Application.ActiveWorkbook.HasVBProject Then
                    FileExtStr = ".xlsm": FileFormatNum = 52
                Else
                    FileExtStr = ".xlsx": FileFormatNum = 51
                End If
            Case 56:
                FileExtStr = ".xls": FileFormatNum = 56
            Case Else:
                FileExtStr = ".xlsb": FileFormatNum = 50
        End Select
    End If
    xFile = FolderName & "\" & Application.ActiveWorkbook.Sheets(1).Name & FileExtStr
    Application.ActiveWorkbook.SaveAs xFile, FileFormat:=FileFormatNum
    Application.ActiveWorkbook.Close False
Next
MsgBox "You can find the files in " & FolderName
Application.ScreenUpdating = True

End Sub

What is (x & 1) and (x >>= 1)?

It is similar to x = (x >> 1).

(operand1)(operator)=(operand2)  implies(=>)  (operand1)=(operand1)(operator)(operand2) 

It shifts the binary value of x by one to the right.

E.g.

int x=3;    // binary form (011) 
x = x >> 1; // zero shifted in from the left, 1 shifted out to the right:
            // x=1, binary form (001)

Access properties file programmatically with Spring?

As you know the newer versions of Spring don't use the PropertyPlaceholderConfigurer and now use another nightmarish construct called PropertySourcesPlaceholderConfigurer. If you're trying to get resolved properties from code, and wish the Spring team gave us a way to do this a long time ago, then vote this post up! ... Because this is how you do it the new way:

Subclass PropertySourcesPlaceholderConfigurer:

public class SpringPropertyExposer extends PropertySourcesPlaceholderConfigurer {

    private ConfigurableListableBeanFactory factory;

    /**
     * Save off the bean factory so we can use it later to resolve properties
     */
    @Override
    protected void processProperties(ConfigurableListableBeanFactory beanFactoryToProcess,
            final ConfigurablePropertyResolver propertyResolver) throws BeansException {
        super.processProperties(beanFactoryToProcess, propertyResolver);

        if (beanFactoryToProcess.hasEmbeddedValueResolver()) {
            logger.debug("Value resolver exists.");
            factory = beanFactoryToProcess;
        }
        else {
            logger.error("No existing embedded value resolver.");
        }
    }

    public String getProperty(String name) {
        Object propertyValue = factory.resolveEmbeddedValue(this.placeholderPrefix + name + this.placeholderSuffix);
        return propertyValue.toString();
    }
}

To use it, make sure to use your subclass in your @Configuration and save off a reference to it for later use.

@Configuration
@ComponentScan
public class PropertiesConfig {

    public static SpringPropertyExposer commonEnvConfig;

    @Bean(name="commonConfig")
    public static PropertySourcesPlaceholderConfigurer commonConfig() throws IOException {
        commonEnvConfig = new SpringPropertyExposer(); //This is a subclass of the return type.
        PropertiesFactoryBean commonConfig = new PropertiesFactoryBean();
        commonConfig.setLocation(new ClassPathResource("META-INF/spring/config.properties"));
        try {
            commonConfig.afterPropertiesSet();
        }
        catch (IOException e) {
            e.printStackTrace();
            throw e;
        }
        commonEnvConfig.setProperties(commonConfig.getObject());
        return commonEnvConfig;
    }
}

Usage:

Object value = PropertiesConfig.commonEnvConfig.getProperty("key.subkey");

Automatically deleting related rows in Laravel (Eloquent ORM)

There are 3 approaches to solving this:

1. Using Eloquent Events On Model Boot (ref: https://laravel.com/docs/5.7/eloquent#events)

class User extends Eloquent
{
    public static function boot() {
        parent::boot();

        static::deleting(function($user) {
             $user->photos()->delete();
        });
    }
}

2. Using Eloquent Event Observers (ref: https://laravel.com/docs/5.7/eloquent#observers)

In your AppServiceProvider, register the observer like so:

public function boot()
{
    User::observe(UserObserver::class);
}

Next, add an Observer class like so:

class UserObserver
{
    public function deleting(User $user)
    {
         $user->photos()->delete();
    }
}

3. Using Foreign Key Constraints (ref: https://laravel.com/docs/5.7/migrations#foreign-key-constraints)

$table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');

How to force remounting on React components?

Change the key of the component.

<Component key="1" />
<Component key="2" />

Component will be unmounted and a new instance of Component will be mounted since the key has changed.

edit: Documented on You Probably Don't Need Derived State:

When a key changes, React will create a new component instance rather than update the current one. Keys are usually used for dynamic lists but are also useful here.

If Radio Button is selected, perform validation on Checkboxes

You must use the equals operator not the assignment like

if(document.form1.radio1[0].checked == true) {
    alert("You have selected Option 1");
}

ng if with angular for string contains

Only the shortcut syntax worked for me *ngIf.

(I think it's the later versions that use this syntax if I'm not mistaken)

<div *ngIf="haystack.indexOf('needle') > -1">
</div>

or

<div *ngIf="haystack.includes('needle')">
</div>

How to convert list of key-value tuples into dictionary?

>>> dict([('A', 1), ('B', 2), ('C', 3)])
{'A': 1, 'C': 3, 'B': 2}

What is the "__v" field in Mongoose

Well, I can't see Tony's solution...so I have to handle it myself...


If you don't need version_key, you can just:

var UserSchema = new mongoose.Schema({
    nickname: String,
    reg_time: {type: Date, default: Date.now}
}, {
    versionKey: false // You should be aware of the outcome after set to false
});

Setting the versionKey to false means the document is no longer versioned.

This is problematic if the document contains an array of subdocuments. One of the subdocuments could be deleted, reducing the size of the array. Later on, another operation could access the subdocument in the array at it's original position.

Since the array is now smaller, it may accidentally access the wrong subdocument in the array.

The versionKey solves this by associating the document with the a versionKey, used by mongoose internally to make sure it accesses the right collection version.

More information can be found at: http://aaronheckmann.blogspot.com/2012/06/mongoose-v3-part-1-versioning.html

Best way to store chat messages in a database?

You could create a database for x conversations which contains all messages of these conversations. This would allow you to add a new Database (or server) each time x exceeds. X is the number conversations your infrastructure supports (depending on your hardware,...).

The problem is still, that there may be big conversations (with a lot of messages) on the same database. e.g. you have database A and database B an each stores e.g. 1000 conversations. It my be possible that there are far more "big" conversations on server A than on server B (since this is user created content). You could add a "master" database that contains a lookup, on which database/server the single conversations can be found (or you have a schema to assign a database from hash/modulo or something).

Maybe you can find real world architectures that deal with the same problems (you may not be the first one), and that have already been solved.

Recursive Fibonacci

int fib(int x) 
{
    if (x == 0)
      return 0;
    else if (x == 1 || x == 2) 
      return 1;
    else 
      return (fib(x - 1) + fib(x - 2));
}

What is the difference between dim and set in vba


However, I don't think this is what you're really asking.

Sometimes I use:

    Dim r as Range
    r = Range("A1")

This will never work. Without Set you will receive runtime error #91 Object variable or With block variable not set. This is because you must use Set to assign a variables value to an object reference. Then the code above will work.

I think the code below illustrates what you're really asking about. Let's suppose we don't declare a type and let r be a Variant type instead.

Public Sub test()
    Dim r
    debug.print TypeName(r)

    Set r = Range("A1")
    debug.print TypeName(r)

    r = Range("A1")
    debug.print TypeName(r)
End Sub

So, let's break down what happens here.

  1. r is declared as a Variant

    `Dim r` ' TypeName(r) returns "Empty", which is the value for an uninitialized variant
    
  2. r is set to the Range containing cell "A1"

    Set r = Range("A1") ' TypeName(r) returns "Range"
    
  3. r is set to the value of the default property of Range("A1").

    r = Range("A1") ' TypeName(r) returns "String"
    

In this case, the default property of a Range is .Value, so the following two lines of code are equivalent.

r = Range("A1")
r = Range("A1").Value

For more about default object properties, please see Chip Pearson's "Default Member of a Class".


As for your Set example:

Other times I use

Set r = Range("A1")

This wouldn't work without first declaring that r is a Range or Variant object... using the Dim statement - unless you don't have Option Explicit enabled, which you should. Always. Otherwise, you're using identifiers that you haven't declared and they are all implicitly declared as Variants.

How to set zoom level in google map

Your code below is zooming the map to fit the specified bounds:

addMarker(27.703402,85.311668,'New Road');
center = bounds.getCenter();
map.fitBounds(bounds);

If you only have 1 marker and add it to the bounds, that results in the closest zoom possible:

function addMarker(lat, lng, info) {
  var pt = new google.maps.LatLng(lat, lng);
  bounds.extend(pt);
}

If you keep track of the number of markers you have "added" to the map (or extended the bounds with), you can only call fitBounds if that number is greater than one. I usually push the markers into an array (for later use) and test the length of that array.

If you will only ever have one marker, don't use fitBounds. Call setCenter, setZoom with the marker position and your desired zoom level.

function addMarker(lat, lng, info) {
  var pt = new google.maps.LatLng(lat, lng);
  map.setCenter(pt);
  map.setZoom(your desired zoom);
}

_x000D_
_x000D_
html,
body,
#map {
  height: 100%;
  width: 100%;
  padding: 0;
  margin: 0;
}
_x000D_
<html>

<head>
  <script src="http://maps.google.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk" type="text/javascript"></script>
  <script type="text/javascript">
    var icon = new google.maps.MarkerImage("http://maps.google.com/mapfiles/ms/micons/blue.png", new google.maps.Size(32, 32), new google.maps.Point(0, 0), new google.maps.Point(16, 32));
    var center = null;
    var map = null;
    var currentPopup;
    var bounds = new google.maps.LatLngBounds();

    function addMarker(lat, lng, info) {
      var pt = new google.maps.LatLng(lat, lng);
      map.setCenter(pt);
      map.setZoom(5);
      var marker = new google.maps.Marker({
        position: pt,
        icon: icon,
        map: map
      });
      var popup = new google.maps.InfoWindow({
        content: info,
        maxWidth: 300
      });
      google.maps.event.addListener(marker, "click", function() {
        if (currentPopup != null) {
          currentPopup.close();
          currentPopup = null;
        }
        popup.open(map, marker);
        currentPopup = popup;
      });
      google.maps.event.addListener(popup, "closeclick", function() {
        map.panTo(center);
        currentPopup = null;
      });
    }

    function initMap() {
      map = new google.maps.Map(document.getElementById("map"), {
        center: new google.maps.LatLng(0, 0),
        zoom: 1,
        mapTypeId: google.maps.MapTypeId.ROADMAP,
        mapTypeControl: false,
        mapTypeControlOptions: {
          style: google.maps.MapTypeControlStyle.HORIZONTAL_BAR
        },
        navigationControl: true,
        navigationControlOptions: {
          style: google.maps.NavigationControlStyle.SMALL
        }
      });
      addMarker(27.703402, 85.311668, 'New Road');
      // center = bounds.getCenter();
      // map.fitBounds(bounds);

    }
  </script>
</head>

<body onload="initMap()" style="margin:0px; border:0px; padding:0px;">
  <div id="map"></div>
</body>

</html>
_x000D_
_x000D_
_x000D_

undefined reference to boost::system::system_category() when compiling

The above error is a linker error... the linker a program that takes one or more objects generated by a compiler and combines them into a single executable program.

You must add -lboost_system to you linker flags which indicates to the linker that it must look for symbols like boost::system::system_category() in the library libboost_system.so.

If you have main.cpp, either:

g++ main.cpp -o main -lboost_system

OR

g++ -c -o main.o main.cpp
g++ main.o -lboost_system

How to change current Theme at runtime in Android

If you want to change theme of an already existing activity, call recreate() after setTheme().

Note: don't call recreate if you change theme in onCreate(), to avoid infinite loop.

Make install, but not to default directories?

Since don't know which version of automake you can use DESTDIR environment variable.
See Makefile to be sure.

For example:

 export DESTDIR="$HOME/Software/LocalInstall" && make -j4 install

Sorting 1 million 8-decimal-digit numbers with 1 MB of RAM

If it is possible to read the input file more than once (your problem statement doesn't say it can't), the following should work. It is described in Benchley's book "Programming Perls." If we store each number in 8 bytes we can store 250,000 numbers in one megabyte. Use a program that makes 40 passes over the input file. On the first pass it reads into memory any integer between 0 and 249,999, sorts the (at most) 250,000 integers and writes them to the output file. The second pass sorts the integers from 250,000 to 499,999 and so on to the 40th pass, which sorts 9,750,000 to 9,999,999.

Java 8 stream's .min() and .max(): why does this compile?

This works because Integer::min resolves to an implementation of the Comparator<Integer> interface.

The method reference of Integer::min resolves to Integer.min(int a, int b), resolved to IntBinaryOperator, and presumably autoboxing occurs somewhere making it a BinaryOperator<Integer>.

And the min() resp max() methods of the Stream<Integer> ask the Comparator<Integer> interface to be implemented.
Now this resolves to the single method Integer compareTo(Integer o1, Integer o2). Which is of type BinaryOperator<Integer>.

And thus the magic has happened as both methods are a BinaryOperator<Integer>.

Is it possible to have SSL certificate for IP address, not domain name?

According to this answer, it is possible, but rarely used.

As for how to get it: I would tend to simply try and order one with the provider of your choice, and enter the IP address instead of a domain during the ordering process.

However, running a site on an IP address to avoid the DNS lookup sounds awfully like unnecessary micro-optimization to me. You will save a few milliseconds at best, and that is per visit, as DNS results are cached on multiple levels.

I don't think your idea makes sense from an optimization viewpoint.

SQL Server: Multiple table joins with a WHERE clause

SELECT p.Name, v.Name
FROM Production.Product p
JOIN Purchasing.ProductVendor pv
ON p.ProductID = pv.ProductID
JOIN Purchasing.Vendor v
ON pv.BusinessEntityID = v.BusinessEntityID
WHERE ProductSubcategoryID = 15
ORDER BY v.Name;

How to create a user in Django?

If you creat user normally, you will not be able to login as password creation method may b different You can use default signup form for that

from django.contrib.auth.forms import UserCreationForm

You can extend that also

from django.contrib.auth.forms import UserCreationForm

class UserForm(UserCreationForm):
    mobile = forms.CharField(max_length=15, min_length=10)
    email = forms.EmailField(required=True)
    class Meta:
        model = User
        fields = ['username', 'password', 'first_name', 'last_name', 'email', 'mobile' ]

Then in view use this class

class UserCreate(CreateView):
    form_class = UserForm
    template_name = 'registration/signup.html'
    success_url = reverse_lazy('list')

    def form_valid(self, form):
        user = form.save()

How to get a random number between a float range?

if you want generate a random float with N digits to the right of point, you can make this :

round(random.uniform(1,2), N)

the second argument is the number of decimals.

Compile/run assembler in Linux?

There is also FASM for Linux.

format ELF executable

segment readable executable

start:
mov eax, 4
mov ebx, 1
mov ecx, hello_msg
mov edx, hello_size
int 80h

mov eax, 1
mov ebx, 0
int 80h

segment readable writeable

hello_msg db "Hello World!",10,0
hello_size = $-hello_msg

It comiles with

fasm hello.asm hello

How to wait for a JavaScript Promise to resolve before resuming function?

You can do it manually. (I know, that that isn't great solution, but..) use while loop till the result hasn't a value

kickOff().then(function(result) {
   while(true){
       if (result === undefined) continue;
       else {
            $("#output").append(result);
            return;
       }
   }
});

How to trigger Jenkins builds remotely and to pass parameters

You can trigger Jenkins builds remotely and to pass parameters by using the following query.

JENKINS_URL/job/job-name/buildWithParameters?token=TOKEN_NAME&param_name1=value&param_name1=value

JENKINS_URL (can be) = https://<your domain name or server address>

TOKE_NAME can be created using configure tab

How to calculate age (in years) based on Date of Birth and getDate()

What about a solution with only date functions, not math, not worries about leap year

CREATE FUNCTION dbo.getAge(@dt datetime) 
RETURNS int
AS
BEGIN
    RETURN 
        DATEDIFF(yy, @dt, getdate())
        - CASE 
            WHEN 
                MONTH(@dt) > MONTH(GETDATE()) OR 
                (MONTH(@dt) = MONTH(GETDATE()) AND DAY(@dt) > DAY(GETDATE())) 
            THEN 1 
            ELSE 0 
        END
END

Add a reference column migration in Rails 4

if you like another alternate approach with up and down method try this:

  def up
    change_table :uploads do |t|
      t.references :user, index: true
    end
  end

  def down
    change_table :uploads do |t|
      t.remove_references :user, index: true
    end
  end

8080 port already taken issue when trying to redeploy project from Spring Tool Suite IDE

If you are using linux system, use the below command.

fuser -k some_port_number/tcp - that will kill that process.

Sample:-

fuser -k 8080/tcp

Second Option: Configure the tomcat to use a new port

How to connect html pages to mysql database?

HTML are markup languages, basically they are set of tags like <html>, <body>, which is used to present a website using , and as a whole. All these, happen in the clients system or the user you will be browsing the website.

Now, Connecting to a database, happens on whole another level. It happens on server, which is where the website is hosted.

So, in order to connect to the database and perform various data related actions, you have to use server-side scripts, like , , etc.

Now, lets see a snippet of connection using MYSQLi Extension of PHP

$db = mysqli_connect('hostname','username','password','databasename');

This single line code, is enough to get you started, you can mix such code, combined with HTML tags to create a HTML page, which is show data based pages. For example:

<?php
    $db = mysqli_connect('hostname','username','password','databasename');
?>
<html>
    <body>
          <?php
                $query = "SELECT * FROM `mytable`;";
                $result = mysqli_query($db, $query);
                while($row = mysqli_fetch_assoc($result)) {
                      // Display your datas on the page
                }
          ?>
    </body>
</html>

In order to insert new data into the database, you can use phpMyAdmin or write a INSERT query and execute them.

How to make a Qt Widget grow with the window size?

In Designer, activate the centralWidget and assign a layout, e.g. horizontal or vertical layout. Then your QFormLayout will automatically resize.

Image of Designer

Always make sure, that all widgets have a layout! Otherwise, automatic resizing will break with that widget!

See also

Controls insist on being too large, and won't resize, in QtDesigner

Where is jarsigner?

It's in the bin folder of your java JDK install (Java SE). If you only have the JRE installed you probably don't have it.

How to change heatmap.2 color range in R?

You could try to create your own color palette using the RColorBrewer package

my_palette <- colorRampPalette(c("green", "black", "red"))(n = 1000)

and see how this looks like. But I assume in your case only scaling would help if you really want to keep the black in "the middle". You can simply use my_palette instead of the redgreen()

I recommend that you check out the RColorBrewer package, they have pretty nice in-built palettes, and see interactive website for colorbrewer.

mongodb/mongoose findMany - find all documents with IDs listed in array

This code works for me just fine as of mongoDB v4.2 and mongoose 5.9.9:

const Ids = ['id1','id2','id3']
const results = await Model.find({ _id: Ids})

and the Ids can be of type ObjectId or String

Cannot read property 'length' of null (javascript)

I tried this:

if(capital !== null){ 
//Capital has something 
}

Fastest Way of Inserting in Entity Framework

Have you ever tried to insert through a background worker or task?

In my case, im inserting 7760 registers, distributed in 182 different tables with foreign key relationships ( by NavigationProperties).

Without the task, it took 2 minutes and a half. Within a Task ( Task.Factory.StartNew(...) ), it took 15 seconds.

Im only doing the SaveChanges() after adding all the entities to the context. (to ensure data integrity)

Changing Vim indentation behavior by file type

While you can configure Vim's indentation just fine using the indent plugin or manually using the settings, I recommend using a python script called Vindect that automatically sets the relevant settings for you when you open a python file. Use this tip to make using Vindect even more effective. When I first started editing python files created by others with various indentation styles (tab vs space and number of spaces), it was incredibly frustrating. But Vindect along with this indent file

Also recommend:

GIT commit as different user without email / or only email

The --author option doesn't work:

*** Please tell me who you are.

Run

  git config --global user.email "[email protected]"
  git config --global user.name "Your Name"

This does:

git -c user.name='A U Thor' -c [email protected] commit

Android - SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length

I have run into the same error entries in LogCat. In my case it's caused by the 3rd party keyboard I am using. When I change it back to Android keyboard, the error entry does not show up any more.

How to start a Process as administrator mode in C#

You probably need to set your application as an x64 app.

The IIS Snap In only works in 64 bit and doesn't work in 32 bit, and a process spawned from a 32 bit app seems to work to be a 32 bit process and the same goes for 64 bit apps.

Look at: Start process as 64 bit

How to run multiple DOS commands in parallel?

if you have multiple parameters use the syntax as below. I have a bat file with script as below:

start "dummyTitle" [/options] D:\path\ProgramName.exe Param1 Param2 Param3 
start "dummyTitle" [/options] D:\path\ProgramName.exe Param4 Param5 Param6 

This will open multiple consoles.

How do you make Vim unhighlight what you searched for?

            *:noh* *:nohlsearch*
:noh[lsearch]       Stop the highlighting for the 'hlsearch' option.  It
            is automatically turned back on when using a search
            command, or setting the 'hlsearch' option.
            This command doesn't work in an autocommand, because
            the highlighting state is saved and restored when
            executing autocommands |autocmd-searchpat|.
            Same thing for when invoking a user function.

I found it just under :help #, which I keep hitting all the time, and which highlights all the words on the current page like the current one.

How to style the <option> with only CSS?

I've played around with select items before and without overriding the functionality with JavaScript, I don't think it's possible in Chrome. Whether you use a plugin or write your own code, CSS only is a no go for Chrome/Safari and as you said, Firefox is better at dealing with it.

How to print jquery object/array

I was having similar problem and

var dataObj = JSON.parse(data);

console.log(dataObj[0].category); //will return Damskie
console.log(dataObj[1].category); //will return Meskie

This solved my problem. Thanks Selvakumar Arumugam

Including another class in SCSS

Another option could be using an Attribute Selector:

[class^="your-class-name"]{
  //your style here
}

Whereas every class starting with "your-class-name" uses this style.

So in your case, you could do it like so:

[class^="class"]{
  display: inline-block;
  //some other properties
  &:hover{
   color: darken(#FFFFFF, 10%);
 }  
}

.class-b{
  //specifically for class b
  width: 100px;
  &:hover{
     color: darken(#FFFFFF, 20%);
  }
}

More about Attribute Selectors on w3Schools

error LNK2001: unresolved external symbol (C++)

Sounds like you are using Microsoft Visual C++. If that is the case, then the most possibility is that you don't compile your two.cpp with one.cpp (one.cpp is the implementation for one.h).

If you are from command line (cmd.exe), then try this first: cl -o two.exe one.cpp two.cpp

If you are from IDE, right click on the project name from Solution Explore. Then choose Add, Existing Item.... Add one.cpp into your project.

How to open a local disk file with JavaScript?

Javascript cannot typically access local files in new browsers but the XMLHttpRequest object can be used to read files. So it is actually Ajax (and not Javascript) which is reading the file.

If you want to read the file abc.txt, you can write the code as:

var txt = '';
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function(){
  if(xmlhttp.status == 200 && xmlhttp.readyState == 4){
    txt = xmlhttp.responseText;
  }
};
xmlhttp.open("GET","abc.txt",true);
xmlhttp.send();

Now txt contains the contents of the file abc.txt.

How to show the Project Explorer window in Eclipse

For me it was like this...

Window->Show View->Other->General->Project Explorer

Or

Window->Open Perspective->Other->Java (default)

Why is using "for...in" for array iteration a bad idea?

Short answer: It's just not worth it.


Longer answer: It's just not worth it, even if sequential element order and optimal performance aren't required.


Long answer: It's just not worth it...

  • Using for (var property in array) will cause array to be iterated over as an object, traversing the object prototype chain and ultimately performing slower than an index-based for loop.
  • for (... in ...) is not guaranteed to return the object properties in sequential order, as one might expect.
  • Using hasOwnProperty() and !isNaN() checks to filter the object properties is an additional overhead causing it to perform even slower and negates the key reason for using it in the first place, i.e. because of the more concise format.

For these reasons an acceptable trade-off between performance and convenience doesn't even exist. There's really no benefit unless the intent is to handle the array as an object and perform operations on the object properties of the array.

Git - How to close commit editor?

Alternatives to Nano (might make your life easier):

On Windows, use notepad. In command prompt type:

git config core.editor notepad

On Ubuntu / Linux, use text editor (gedit). In terminal window type:

git config core.editor gedit

How to write to the Output window in Visual Studio?

Useful tip - if you use __FILE__ and __LINE__ then format your debug as:

"file(line): Your output here"

then when you click on that line in the output window Visual Studio will jump directly to that line of code. An example:

#include <Windows.h>
#include <iostream>
#include <sstream>

void DBOut(const char *file, const int line, const WCHAR *s)
{
    std::wostringstream os_;
    os_ << file << "(" << line << "): ";
    os_ << s;
    OutputDebugStringW(os_.str().c_str());
}

#define DBOUT(s)       DBOut(__FILE__, __LINE__, s)

I wrote a blog post about this so I always knew where I could look it up: https://windowscecleaner.blogspot.co.nz/2013/04/debug-output-tricks-for-visual-studio.html

Programmatically center TextView text

if your text size is small, you should make the width of your text view to be "fill_parent". After that, you can set your TextView Gravity to center :

TextView textView = new TextView(this);
textView.setText(message);
textView.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));
textView.setGravity(Gravity.CENTER);

How to remove duplicate objects in a List<MyObject> without equals/hashcode?

  1. override hashCode() and equals(..) using those 4 fields
  2. use new HashSet<Blog>(blogList) - this will give you a Set which has no duplicates by definition

Update: Since you can't change the class, here's an O(n^2) solution:

  • create a new list
  • iterate the first list
  • in an inner loop iterate the second list and verify if it has an element with the same fields

You can make this more efficient if you provide a HashSet data structure with externalized hashCode() and equals(..) methods.

How can I select all options of multi-select select box on click?

try this,

call a method selectAll() onclick and write a function of code as follows

function selectAll(){
    $("#id").find("option").each(function(this) {
    $(this).attr('selected', 'selected');
    });
}

target="_blank" vs. target="_new"

Caution - remember to always include the "quotes" - at least on Chrome, target=_blank (no quotes) is NOT THE SAME as target="_blank" (with quotes).

The latter opens each link in a new tab/window. The former (missing quotes) opens the first link you click in one new tab/window, then overwrites that same tab/window with each subsequent link you click (that's named also with the missing quotes).

Merge trunk to branch in Subversion

Last revision merged from trunk to branch can be found by running this command inside the working copy directory:

svn log -v --stop-on-copy

Get page title with Selenium WebDriver using Java

If you're using Selenium 2.0 / Webdriver you can call driver.getTitle() or driver.getPageSource() if you want to search through the actual page source.

What does the "yield" keyword do?

Yield is an object

A return in a function will return a single value.

If you want a function to return a huge set of values, use yield.

More importantly, yield is a barrier.

like barrier in the CUDA language, it will not transfer control until it gets completed.

That is, it will run the code in your function from the beginning until it hits yield. Then, it’ll return the first value of the loop.

Then, every other call will run the loop you have written in the function one more time, returning the next value until there isn't any value to return.

How to get current date in jquery?

You can add an extension method to javascript.

Date.prototype.today = function () {
    return ((this.getDate() < 10) ? "0" : "") + this.getDate() + "/" + (((this.getMonth() + 1) < 10) ? "0" : "") + (this.getMonth() + 1) + "/" + this.getFullYear();
}

RecyclerView vs. ListView

RecyclerView info

The RecyclerView was introduced with Android 5.0 (Lollipop). it is included in the Support Library. Thus, it is compatible with Android API Level 7.

Similarly to the ListView, RecyclerView’s main idea is to provide listing functionality in a performance friendly manner. The ‘Recycler’ part of this view’s name is not there by coincidence. The RecyclerView can actually recycle the items with which it’s currently working. The recycling process is done thanks to a pattern called View Holder.

Pros & Cons of RecyclerView

Pros:

  • integrated animations for adding, updating and removing items
  • enforces the recycling of views by using the ViewHolder pattern
  • supports both grids and lists
  • supports vertical and horizontal scrolling
  • can be used together with DiffUtil

Cons:

  • adds complexity
  • no OnItemClickListener

ListView info

The ListView has been around since the very beginning of Android. It was available even in API Level 1 and it has the same purpose as the RecyclerView.

The usage of the ListView is actually really simple. In this aspect, it’s not like its successor. The learning curve is smoother than the one for the RecyclerView. Thus, it is easier to grasp. We don’t have to deal with things like the LayoutManager, ItemAnimator or DiffUtil.

Pros & Cons of ListView

Pros:

  • simple usage
  • default adapters
  • available OnItemClickListener
  • it’s the foundation of the ExpandableListView

Cons:

  • doesn’t embrace the usage of the ViewHolder pattern

Is there functionality to generate a random character in Java?

My propose for generating random string with mixed case like: "DthJwMvsTyu".
This algorithm based on ASCII codes of letters when its codes a-z (97 to 122) and A-Z (65 to 90) differs in 5th bit (2^5 or 1 << 5 or 32).

random.nextInt(2): result is 0 or 1.

random.nextInt(2) << 5: result is 0 or 32.

Upper A is 65 and lower a is 97. Difference is only on 5th bit (32) so for generating random char we do binary OR '|' random charCaseBit (0 or 32) and random code from A to Z (65 to 90).

public String fastestRandomStringWithMixedCase(int length) {
    Random random = new Random();
    final int alphabetLength = 'Z' - 'A' + 1;
    StringBuilder result = new StringBuilder(length);
    while (result.length() < length) {
        final char charCaseBit = (char) (random.nextInt(2) << 5);
        result.append((char) (charCaseBit | ('A' + random.nextInt(alphabetLength))));
    }
    return result.toString();
}

C Program to find day of week given date

For Day of Week, years 2000 - 2099.

uint8_t rtc_DayOfWeek(uint8_t year, uint8_t month, uint8_t day)
{
    //static const uint8_t month_offset_table[] = {0, 3, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5}; // Typical table.

    // Added 1 to Jan, Feb. Subtracted 1 from each instead of adding 6 in calc below.

    static const uint8_t month_offset_table[] = {0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4};

    // Year is 0 - 99, representing years 2000 - 2099

    // Month starts at 0.

    // Day starts at 1.

    // Subtract 1 in calc for Jan, Feb, only in leap years.
    // Subtracting 1 from year has the effect of subtracting 2 in leap years, subtracting 1 otherwise.
    // Adding 1 for Jan, Feb in Month Table so calc ends up subtracting 1 for Jan, Feb, only in leap years.
    // All of this complication to avoid the check if it is a leap year.
    if (month < 2) {
        year--;
    }

    // Century constant is 6. Subtract 1 from Month Table, so difference is 7.

    // Sunday (0), Monday (1) ...

    return (day + month_offset_table[month] + year + (year >> 2)) % 7;

} /* end rtc_DayOfWeek() */

403 - Forbidden: Access is denied. ASP.Net MVC

I had the same issue (on windows server 2003), check in the IIS console if you have allowed ASP.NET v4 service extension (under IIS / ComputerName / Web Service extensions)

How to connect android wifi to adhoc wifi?

You are correct, but note that you can do it the other way around - use Android Wifi tethering that sets up the phone as a base station and connect to said base station from the laptop.

How to delete a row from GridView?

The default answer is to remove the item from whatever collection you're using as the GridView's DataSource.

If that option is undesirable then I recommend that you use the GridView's RowDataBound event to selectively set the row's (e.Row) Visible property to false.

Wait until all jQuery Ajax requests are done?

On the basis of @BBonifield answer, I wrote a utility function so that semaphore logic is not spread in all the ajax calls.

untilAjax is the utility function which invokes a callback function when all the ajaxCalls are completed.

ajaxObjs is a array of ajax setting objects [http://api.jquery.com/jQuery.ajax/].

fn is callback function

function untilAjax(ajaxObjs, fn) {
  if (!ajaxObjs || !fn) {
    return;
  }
  var ajaxCount = ajaxObjs.length,
    succ = null;

  for (var i = 0; i < ajaxObjs.length; i++) { //append logic to invoke callback function once all the ajax calls are completed, in success handler.
    succ = ajaxObjs[i]['success'];
    ajaxObjs[i]['success'] = function(data) { //modified success handler
      if (succ) {
        succ(data);
      }
      ajaxCount--;
      if (ajaxCount == 0) {
        fn(); //modify statement suitably if you want 'this' keyword to refer to another object
      }
    };
    $.ajax(ajaxObjs[i]); //make ajax call
    succ = null;
  };

Example: doSomething function uses untilAjax.

function doSomething() {
  // variable declarations
  untilAjax([{
    url: 'url2',
    dataType: 'json',
    success: function(data) {
      //do something with success data
    }
  }, {
    url: 'url1',
    dataType: 'json',
    success: function(data) {
      //do something with success data
    }
  }, {
    url: 'url2',
    dataType: 'json',
    success: function(response) {
      //do something with success data
    }
  }], function() {
    // logic after all the calls are completed.
  });
}

Border in shape xml

If you want make a border in a shape xml. You need to use:

For the external border,you need to use:

<stroke/>

For the internal background,you need to use:

<solid/>

If you want to set corners,you need to use:

<corners/>

If you want a padding betwen border and the internal elements,you need to use:

<padding/>

Here is a shape xml example using the above items. It works for me

<shape xmlns:android="http://schemas.android.com/apk/res/android"> 
  <stroke android:width="2dp" android:color="#D0CFCC" /> 
  <solid android:color="#F8F7F5" /> 
  <corners android:radius="10dp" />
  <padding android:left="2dp" android:top="2dp" android:right="2dp" android:bottom="2dp" />
</shape>

How to redirect the output of print to a TXT file

Redirect sys.stdout to an open file handle and then all printed output goes to a file:

import sys
filename  = open("outputfile",'w')
sys.stdout = filename
print "Anything printed will go to the output file"

How do I concatenate multiple C++ strings on one line?

In 5 years nobody has mentioned .append?

#include <string>

std::string s;
s.append("Hello world, ");
s.append("nice to see you, ");
s.append("or not.");

java SSL and cert keystore

First of all, there're two kinds of keystores.

Individual and General

The application will use the one indicated in the startup or the default of the system.

It will be a different folder if JRE or JDK is running, or if you check the personal or the "global" one.

They are encrypted too

In short, the path will be like:

$JAVA_HOME/lib/security/cacerts for the "general one", who has all the CA for the Authorities and is quite important.

What is the largest Safe UDP Packet Size on the Internet

I fear i incur upset reactions but nevertheless, to clarify for me if i'm wrong or those seeing this question and being interested in an answer:

my understanding of https://tools.ietf.org/html/rfc1122 whose status is "an official specification" and as such is the reference for the terminology used in this question and which is neither superseded by another RFC nor has errata contradicting the following:

theoretically, ie. based on the written spec., UDP like given by https://tools.ietf.org/html/rfc1122#section-4 has no "packet size". Thus the answer could be "indefinite"

In practice, which is what this questions likely seeked (and which could be updated for current tech in action), this might be different and I don't know.

I apologize if i caused upsetting. https://tools.ietf.org/html/rfc1122#page-8 The "Internet Protocol Suite" and "Architectural Assumptions" don't make clear to me the "assumption" i was on, based on what I heard, that the layers are separate. Ie. the layer UDP is in does not have to concern itself with the layer IP is in (and the IP layer does have things like Reassembly, EMTU_R, Fragmentation and MMS_R (https://tools.ietf.org/html/rfc1122#page-56))

SQL TRUNCATE DATABASE ? How to TRUNCATE ALL TABLES

No nonsense script this:

EXEC sp_MSForEachTable 'ALTER TABLE ? NOCHECK CONSTRAINT ALL'
EXEC sp_MSForEachTable 'DELETE FROM ?'
EXEC sp_MSForEachTable 'ALTER TABLE ? CHECK CONSTRAINT ALL'
EXEC sp_MSforeachtable 'DBCC CHECKIDENT ( ''?'', RESEED, 0)'
GO

Truncate will still not work if you have foreign keys in tables. This script will reset all identity columns as well.

How do I convert a Swift Array to a String?

If the array contains strings, you can use the String's join method:

var array = ["1", "2", "3"]

let stringRepresentation = "-".join(array) // "1-2-3"

In Swift 2:

var array = ["1", "2", "3"]

let stringRepresentation = array.joinWithSeparator("-") // "1-2-3"

This can be useful if you want to use a specific separator (hypen, blank, comma, etc).

Otherwise you can simply use the description property, which returns a string representation of the array:

let stringRepresentation = [1, 2, 3].description // "[1, 2, 3]"

Hint: any object implementing the Printable protocol has a description property. If you adopt that protocol in your own classes/structs, you make them print friendly as well

In Swift 3

  • join becomes joined, example [nil, "1", "2"].flatMap({$0}).joined()
  • joinWithSeparator becomes joined(separator:) (only available to Array of Strings)

In Swift 4

var array = ["1", "2", "3"]
array.joined(separator:"-")

plot different color for different categorical levels using matplotlib

With df.plot()

Normally when quickly plotting a DataFrame, I use pd.DataFrame.plot(). This takes the index as the x value, the value as the y value and plots each column separately with a different color. A DataFrame in this form can be achieved by using set_index and unstack.

import matplotlib.pyplot as plt
import pandas as pd

carat = [5, 10, 20, 30, 5, 10, 20, 30, 5, 10, 20, 30]
price = [100, 100, 200, 200, 300, 300, 400, 400, 500, 500, 600, 600]
color =['D', 'D', 'D', 'E', 'E', 'E', 'F', 'F', 'F', 'G', 'G', 'G',]

df = pd.DataFrame(dict(carat=carat, price=price, color=color))

df.set_index(['color', 'carat']).unstack('color')['price'].plot(style='o')
plt.ylabel('price')

plot

With this method you do not have to manually specify the colors.

This procedure may make more sense for other data series. In my case I have timeseries data, so the MultiIndex consists of datetime and categories. It is also possible to use this approach for more than one column to color by, but the legend is getting a mess.

How to add click event to a iframe with JQuery

You can use this code to bind click an element which is in iframe.

_x000D_
_x000D_
jQuery('.class_in_iframe',jQuery('[id="id_of_iframe"]')[0].contentWindow.document.body).on('click',function(){ _x000D_
 console.log("triggered !!")_x000D_
});
_x000D_
_x000D_
_x000D_

Shortcut for creating single item list in C#

Michael's idea of using extension methods leads to something even simpler:

public static List<T> InList<T>(this T item)
{
    return new List<T> { item };
}

So you could do this:

List<string> foo = "Hello".InList();

I'm not sure whether I like it or not, mind you...

What causes a java.lang.ArrayIndexOutOfBoundsException and how do I prevent it?

ArrayIndexOutOfBounds means you are trying to index a position within an array that is not allocated.

In this case:

String[] name = { "tom", "dick", "harry" };
for (int i = 0; i <= name.length; i++) {
    System.out.println(name[i]);
}
  • name.length is 3 since the array has been defined with 3 String objects.
  • When accessing the contents of an array, position starts from 0. Since there are 3 items, it would mean name[0]="tom", name[1]="dick" and name[2]="harry
  • When you loop, since i can be less than or equal to name.length, you are trying to access name[3] which is not available.

To get around this...

  • In your for loop, you can do i < name.length. This would prevent looping to name[3] and would instead stop at name[2]

    for(int i = 0; i<name.length; i++)

  • Use a for each loop

    String[] name = { "tom", "dick", "harry" }; for(String n : name) { System.out.println(n); }

  • Use list.forEach(Consumer action) (requires Java8)

    String[] name = { "tom", "dick", "harry" }; Arrays.asList(name).forEach(System.out::println);

  • Convert array to stream - this is a good option if you want to perform additional 'operations' to your array e.g. filter, transform the text, convert to a map etc (requires Java8)

    String[] name = { "tom", "dick", "harry" }; --- Arrays.asList(name).stream().forEach(System.out::println); --- Stream.of(name).forEach(System.out::println);

Add A Year To Today's Date

In case you want to add years to specific date besides today's date using either years, or months, or days. You can do the following

var christmas2000 = new Date(2000, 12, 25); 
christmas2000.setFullYear(christmas2000.getFullYear() + 5); // using year: next 5 years
christmas2000.setFullYear(christmas2000.getMonth() + 24); // using months: next 24 months
christmas2000.setFullYear(christmas2000.getDay() + 365); // using days: next 365 months

Detect iPad users using jQuery?

iPad Detection

You should be able to detect an iPad user by taking a look at the userAgent property:

var is_iPad = navigator.userAgent.match(/iPad/i) != null;

iPhone/iPod Detection

Similarly, the platform property to check for devices like iPhones or iPods:

function is_iPhone_or_iPod(){
     return navigator.platform.match(/i(Phone|Pod))/i)
}

Notes

While it works, you should generally avoid performing browser-specific detection as it can often be unreliable (and can be spoofed). It's preferred to use actual feature-detection in most cases, which can be done through a library like Modernizr.

As pointed out in Brennen's answer, issues can arise when performing this detection within the Facebook app. Please see his answer for handling this scenario.

Related Resources

How to force R to use a specified factor level as reference in a regression?

Others have mentioned the relevel command which is the best solution if you want to change the base level for all analyses on your data (or are willing to live with changing the data).

If you don't want to change the data (this is a one time change, but in the future you want the default behavior again), then you can use a combination of the C (note uppercase) function to set contrasts and the contr.treatments function with the base argument for choosing which level you want to be the baseline.

For example:

lm( Sepal.Width ~ C(Species,contr.treatment(3, base=2)), data=iris )

Return a `struct` from a function in C

struct var e2 address pushed as arg to callee stack and values gets assigned there. In fact, get() returns e2's address in eax reg. This works like call by reference.

How to delete a character from a string using Python

Strings are immutable. But you can convert them to a list, which is mutable, and then convert the list back to a string after you've changed it.

s = "this is a string"

l = list(s)  # convert to list

l[1] = ""    # "delete" letter h (the item actually still exists but is empty)
l[1:2] = []  # really delete letter h (the item is actually removed from the list)
del(l[1])    # another way to delete it

p = l.index("a")  # find position of the letter "a"
del(l[p])         # delete it

s = "".join(l)  # convert back to string

You can also create a new string, as others have shown, by taking everything except the character you want from the existing string.

What does git rev-parse do?

Just to elaborate on the etymology of the command name rev-parse, Git consistently uses the term rev in plumbing commands as short for "revision" and generally meaning the 40-character SHA1 hash for a commit. The command rev-list for example prints a list of 40-char commit hashes for a branch or whatever.

In this case the name might be expanded to parse-a-commitish-to-a-full-SHA1-hash. While the command has the several ancillary functions mentioned in Tuxdude's answer, its namesake appears to be the use case of transforming a user-friendly reference like a branch name or abbreviated hash into the unambiguous 40-character SHA1 hash most useful for many programming/plumbing purposes.

I know I was thinking it was "reverse-parse" something for quite a while before I figured it out and had the same trouble making sense of the terms "massaging" and "manipulation" :)

Anyway, I find this "parse-to-a-revision" notion a satisfying way to think of it, and a reliable concept for bringing this command to mind when I need that sort of thing. Frequently in scripting Git you take a user-friendly commit reference as user input and generally want to get it resolved to a validated and unambiguous working reference as soon after receiving it as possible. Otherwise input translation and validation tends to proliferate through the script.

Scroll to element on click in Angular 4

In Angular you can use ViewChild and ElementRef: give your HTML element a ref

<div #myDiv > 

and inside your component:

import { ViewChild, ElementRef } from '@angular/core';
@ViewChild('myDiv') myDivRef: ElementRef;

you can use this.myDivRef.nativeElement to get to your element

How do you overcome the svn 'out of date' error?

Thank you. That just resolved it for me. svn update --force /path to filename/

If your recent file in the local directory is the same, there are no prompts. If the file is different, it prompts for tf, mf etc... chosing mf (mine full) insures nothing is overwritten and I could commit when done.

Jay CompuMatter

What are Long-Polling, Websockets, Server-Sent Events (SSE) and Comet?

In the examples below the client is the browser and the server is the webserver hosting the website.

Before you can understand these technologies, you have to understand classic HTTP web traffic first.

Regular HTTP:

  1. A client requests a webpage from a server.
  2. The server calculates the response
  3. The server sends the response to the client.

HTTP

Ajax Polling:

  1. A client requests a webpage from a server using regular HTTP (see HTTP above).
  2. The client receives the requested webpage and executes the JavaScript on the page which requests a file from the server at regular intervals (e.g. 0.5 seconds).
  3. The server calculates each response and sends it back, just like normal HTTP traffic.

Ajax Polling

Ajax Long-Polling:

  1. A client requests a webpage from a server using regular HTTP (see HTTP above).
  2. The client receives the requested webpage and executes the JavaScript on the page which requests a file from the server.
  3. The server does not immediately respond with the requested information but waits until there's new information available.
  4. When there's new information available, the server responds with the new information.
  5. The client receives the new information and immediately sends another request to the server, re-starting the process.

Ajax Long-Polling

HTML5 Server Sent Events (SSE) / EventSource:

  1. A client requests a webpage from a server using regular HTTP (see HTTP above).
  2. The client receives the requested webpage and executes the JavaScript on the page which opens a connection to the server.
  3. The server sends an event to the client when there's new information available.

HTML5 SSE

HTML5 Websockets:

  1. A client requests a webpage from a server using regular http (see HTTP above).
  2. The client receives the requested webpage and executes the JavaScript on the page which opens a connection with the server.
  3. The server and the client can now send each other messages when new data (on either side) is available.

    • Real-time traffic from the server to the client and from the client to the server
    • You'll want to use a server that has an event loop
    • With WebSockets it is possible to connect with a server from another domain.
    • It is also possible to use a third party hosted websocket server, for example Pusher or others. This way you'll only have to implement the client side, which is very easy!
    • If you want to read more, I found these very useful: (article), (article) (tutorial).

HTML5 WebSockets

Comet:

Comet is a collection of techniques prior to HTML5 which use streaming and long-polling to achieve real time applications. Read more on wikipedia or this article.


Now, which one of them should I use for a realtime app (that I need to code). I have been hearing a lot about websockets (with socket.io [a node.js library]) but why not PHP ?

You can use PHP with WebSockets, check out Ratchet.

Convert Promise to Observable

1 Direct Execution / Conversion

Use from to directly convert a previously created Promise to an Observable.

import { from } from 'rxjs';

// getPromise() is called once, the promise is passed to the Observable
const observable$ = from(getPromise());

observable$ will be a hot Observable that effectively replays the Promises value to Subscribers.

It's a hot Observable because the producer (in this case the Promise) is created outside of the Observable. Multiple subscribers will share the same Promise. If the inner Promise has been resolved a new subscriber to the Observable will get its value immediately.

2 Deferred Execution On Every Subscribe

Use defer with a Promise factory function as input to defer the creation and conversion of a Promise to an Observable.

import { defer } from 'rxjs';

// getPromise() is called every time someone subscribes to the observable$
const observable$ = defer(() => getPromise());

observable$ will be a cold Observable.

It's a cold Observable because the producer (the Promise) is created inside of the Observable. Each subscriber will create a new Promise by calling the given Promise factory function.

This allows you to create an observable$ without creating and thus executing a Promise right away and without sharing this Promise with multiple subscribers. Each subscriber to observable$ effectively calls from(promiseFactory()).subscribe(subscriber). So each subscriber creates and converts its own new Promise to a new Observable and attaches itself to this new Observable.

3 Many Operators Accept Promises Directly

Most RxJS operators that combine (e.g. merge, concat, forkJoin, combineLatest ...) or transform observables (e.g. switchMap, mergeMap, concatMap, catchError ...) accept promises directly. If you're using one of them anyway you don't have to use from to wrap a promise first (but to create a cold observable you still might have to use defer).

// Execute two promises simultaneously
forkJoin(getPromise(1), getPromise(2)).pipe(
  switchMap(([v1, v2]) => v1.getPromise(v2)) // map to nested Promise
)

Check the documentation or implementation to see if the operator you're using accepts ObservableInput or SubscribableOrPromise.

type ObservableInput<T> = SubscribableOrPromise<T> | ArrayLike<T> | Iterable<T>;
// Note the PromiseLike ----------------------------------------------------v
type SubscribableOrPromise<T> = Subscribable<T> | Subscribable<never> | PromiseLike<T> | InteropObservable<T>;

The difference between from and defer in an example: https://stackblitz.com/edit/rxjs-6rb7vf

const getPromise = val => new Promise(resolve => {
  console.log('Promise created for', val);
  setTimeout(() => resolve(`Promise Resolved: ${val}`), 5000);
});

// the execution of getPromise('FROM') starts here, when you create the promise inside from
const fromPromise$ = from(getPromise('FROM'));
const deferPromise$ = defer(() => getPromise('DEFER'));

fromPromise$.subscribe(console.log);
// the execution of getPromise('DEFER') starts here, when you subscribe to deferPromise$
deferPromise$.subscribe(console.log);

How do you tell if a string contains another string in POSIX sh?

If you want a ksh only method that is as fast as "test", you can do something like:

contains() # haystack needle
{
    haystack=${1/$2/}
    if [ ${#haystack} -ne ${#1} ] ; then
        return 1
    fi
    return 0
}

It works by deleting the needle in the haystack and then comparing the string length of old and new haystacks.

c#: getter/setter

This means that the compiler defines a backing field at runtime. This is the syntax for auto-implemented properties.

More Information: Auto-Implemented Properties