Programs & Examples On #Editortemplates

Html attributes for EditorFor() in ASP.NET MVC

EditorFor works with metadata, so if you want to add html attributes you could always do it. Another option is to simply write a custom template and use TextBoxFor:

<%= Html.TextBoxFor(model => model.Control.PeriodType, 
    new { disabled = "disabled", @readonly = "readonly" }) %>    

How can I get a side-by-side diff when I do "git diff"?

You can do a side-by-side diff using sdiff as follows:

$ git difftool -y -x sdiff  HEAD^ | less

where HEAD^ is an example that you should replace with whatever you want to diff against.

I found this solution here where there are a couple of other suggestions also. However, this one answer's the OP's question succinctly and clearly.

See the man git-difftool for an explanation of the arguments.


Taking the comments on board, you can create a handy git sdiff command by writing the following executable script:

#!/bin/sh
git difftool -y -x "sdiff -w $(tput cols)" "${@}" | less

Save it as /usr/bin/git-sdiff and chmod +x it. Then you'll be able to do this:

$ git sdiff HEAD^

Extra Tip

As suggested in comments you can use icdiff to do what sdiff does with colored output:

$ more /usr/bin/git-sdiff
#!/bin/sh
git difftool -y -x "icdiff --cols=$(tput cols)" "${@}" | less

Cannot connect to Database server (mysql workbench)

My problem was that the MySQL server wasn't actually installed. I had run the MySQL Installer, but it didn't install the MySQL server.

I reran the installer, click "Add", and then added MySQL server to the list. Now it works fine.

MySQL wait_timeout Variable - GLOBAL vs SESSION

As noted by Riedsio, the session variables do not change after connecting unless you specifically set them; setting the global variable only changes the session value of your next connection.

For example, if you have 100 connections and you lower the global wait_timeout then it will not affect the existing connections, only new ones after the variable was changed.

Specifically for the wait_timeout variable though, there is a twist. If you are using the mysql client in the interactive mode, or the connector with CLIENT_INTERACTIVE set via mysql_real_connect() then you will see the interactive_timeout set for @@session.wait_timeout

Here you can see this demonstrated:

> ./bin/mysql -Bsse 'select @@session.wait_timeout, @@session.interactive_timeout, @@global.wait_timeout, @@global.interactive_timeout' 
70      60      70      60

> ./bin/mysql -Bsse 'select @@wait_timeout'                                                                                                 
70

> ./bin/mysql                                                                                                                               
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 11
Server version: 5.7.12-5 MySQL Community Server (GPL)

Copyright (c) 2009-2016 Percona LLC and/or its affiliates
Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> select @@wait_timeout;
+----------------+
| @@wait_timeout |
+----------------+
|             60 |
+----------------+
1 row in set (0.00 sec)

So, if you are testing this using the client it is the interactive_timeout that you will see when connecting and not the value of wait_timeout

Display open transactions in MySQL

You can use show innodb status (or show engine innodb status for newer versions of mysql) to get a list of all the actions currently pending inside the InnoDB engine. Buried in the wall of output will be the transactions, and what internal process ID they're running under.

You won't be able to force a commit or rollback of those transactions, but you CAN kill the MySQL process running them, which does essentially boil down to a rollback. It kills the processes' connection and causes MySQL to clean up the mess its left.

Here's what you'd want to look for:

------------
TRANSACTIONS
------------
Trx id counter 0 140151
Purge done for trx's n:o < 0 134992 undo n:o < 0 0
History list length 10
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0 0, not started, process no 17004, OS thread id 140621902116624
MySQL thread id 10594, query id 10269885 localhost marc
show innodb status

In this case, there's just one connection to the InnoDB engine right now (my login, running the show query). If that line were an actual connection/stuck transaction you'd want to terminate, you'd then do a kill 10594.

AVD Manager - Cannot Create Android Virtual Device

If you have changed the SDK Path somehow it will not be able to find the SDKs you installed even though it is listing them fine.

I solved by openig Android SDK Manager and in that dialog choosing the menu Tools -> Manage AVDs. And when you open Manage AVDs directly from the toolbar of Eclipse you should Refresh to see the AVD you created.

Group a list of objects by an attribute

Function<Student, List<Object>> compositKey = std ->
                Arrays.asList(std.stud_location());
        studentList.stream().collect(Collectors.groupingBy(compositKey, Collectors.toList()));

If you want to add multiple objects for group by you can simply add the object in compositKey method separating by a comma:

Function<Student, List<Object>> compositKey = std ->
                Arrays.asList(std.stud_location(),std.stud_name());
        studentList.stream().collect(Collectors.groupingBy(compositKey, Collectors.toList()));

Laravel 5.2 redirect back with success message

you can use this :

return redirect()->back()->withSuccess('IT WORKS!');

and use this in your view :

@if(session('success'))
    <h1>{{session('success')}}</h1>
@endif

Java Refuses to Start - Could not reserve enough space for object heap

It seems that for 32-bit servers there is a JVM limitation that cannot be overcome (unless you find a special 32-bit JVM that does not impose a 2GB limit or less).

This thread on The Server Side has more details including several people who tested out various JVMs on 32-bit architectures. IBM's JVM seems to allow 100 more MB but that's not really going to get you what you want.

http://www.theserverside.com/discussions/thread.tss?thread_id=26347

The "real" solution is to use a 64-bit server with a 64-bit JVM to get heaps larger than 2GB per process. However, it's important to also consider the impact of increasing your address size (not just the addressable space) by using a 64-bit JVM. There will likely be performance and memory impacts for processing using less than 4GB of memory.

Food for thought: do each of these jobs really require 2GB of memory? Is there any way for the jobs to be modified to run within 1.8GB so this limit is not a problem?

How to have Ellipsis effect on Text

<Text ellipsizeMode='tail' numberOfLines={2} style={{width:100}}>
    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam at cursus 
</Text>

Result: Lorem ipsum...

Binding an Image in WPF MVVM

Displaying an Image in WPF is much easier than that. Try this:

<Image Source="{Binding DisplayedImagePath}" HorizontalAlignment="Left" 
    Margin="0,0,0,0" Name="image1" Stretch="Fill" VerticalAlignment="Bottom" 
    Grid.Row="8" Width="200"  Grid.ColumnSpan="2" />

And the property can just be a string:

public string DisplayedImage 
{
    get { return @"C:\Users\Public\Pictures\Sample Pictures\Chrysanthemum.jpg"; }
}

Although you really should add your images to a folder named Images in the root of your project and set their Build Action to Resource in the Properties Window in Visual Studio... you could then access them using this format:

public string DisplayedImage 
{
    get { return "/AssemblyName;component/Images/ImageName.jpg"; }
}

UPDATE >>>

As a final tip... if you ever have a problem with a control not working as expected, simply type 'WPF', the name of that control and then the word 'class' into a search engine. In this case, you would have typed 'WPF Image Class'. The top result will always be MSDN and if you click on the link, you'll find out all about that control and most pages have code examples as well.


UPDATE 2 >>>

If you followed the examples from the link to MSDN and it's not working, then your problem is not the Image control. Using the string property that I suggested, try this:

<StackPanel>
    <Image Source="{Binding DisplayedImagePath}" />
    <TextBlock Text="{Binding DisplayedImagePath}" />
</StackPanel>

If you can't see the file path in the TextBlock, then you probably haven't set your DataContext to the instance of your view model. If you can see the text, then the problem is with your file path.


UPDATE 3 >>>

In .NET 4, the above Image.Source values would work. However, Microsoft made some horrible changes in .NET 4.5 that broke many different things and so in .NET 4.5, you'd need to use the full pack path like this:

<Image Source="pack://application:,,,/AssemblyName;component/Images/image_to_use.png">

For further information on pack URIs, please see the Pack URIs in WPF page on Microsoft Docs.

Xcode error: Code signing is required for product type 'Application' in SDK 'iOS 10.0'

Xcode 11.4

Click on: 1. Your project 2. Signing & Capabilities 3. Select your Team.

enter image description here

How to restrict SSH users to a predefined set of commands after login?

ssh follows the rsh tradition by using the user's shell program from the password file to execute commands.

This means that we can solve this without involving ssh configuration in any way.

If you don't want the user to be able to have shell access, then simply replace that user's shell with a script. If you look in /etc/passwd you will see that there is a field which assigns a shell command interpreter to each user. The script is used as the shell both for their interactive login ssh user@host as well as for commands ssh user@host command arg ....

Here is an example. I created a user foo whose shell is a script. The script prints the message my arguments are: followed by its arguments (each on a separate line and in angle brackets) and terminates. In the log in case, there are no arguments. Here is what happens:

webserver:~# ssh foo@localhost
foo@localhost's password:
Linux webserver [ snip ]
[ snip ]
my arguments are:
Connection to localhost closed.

If the user tries to run a command, it looks like this:

webserver:~# ssh foo@localhost cat /etc/passwd
foo@localhost's password:
my arguments are:
<-c>
<cat /etc/passwd>

Our "shell" receives a -c style invocation, with the entire command as one argument, just the same way that /bin/sh would receive it.

So as you can see, what we can do now is develop the script further so that it recognizes the case when it has been invoked with a -c argument, and then parses the string (say by pattern matching). Those strings which are allowed can be passed to the real shell by recursively invoking /bin/bash -c <string>. The reject case can print an error message and terminate (including the case when -c is missing).

You have to be careful how you write this. I recommend writing only positive matches which allow only very specific things, and disallow everything else.

Note: if you are root, you can still log into this account by overriding the shell in the su command, like this su -s /bin/bash foo. (Substitute shell of choice.) Non-root cannot do this.

Here is an example script: restrict the user into only using ssh for git access to repositories under /git.

#!/bin/sh

if [ $# -ne 2 ] || [ "$1" != "-c" ] ; then
  printf "interactive login not permitted\n"
  exit 1
fi

set -- $2

if [ $# != 2 ] ; then
  printf "wrong number of arguments\n"
  exit 1
fi

case "$1" in
  ( git-upload-pack | git-receive-pack )
    ;; # continue execution
  ( * )
    printf "command not allowed\n"
    exit 1
    ;;
esac

# Canonicalize the path name: we don't want escape out of
# git via ../ path components.

gitpath=$(readlink -f "$2")  # GNU Coreutils specific

case "$gitpath" in
  ( /git/* )
     ;; # continue execution
  ( * )
    printf "access denied outside of /git\n"
    exit 1
    ;;
esac

if ! [ -e "$gitpath" ] ; then
   printf "that git repo doesn't exist\n"
   exit 1
fi

"$1" "$gitpath"

Of course, we are trusting that these Git programs git-upload-pack and git-receive-pack don't have holes or escape hatches that will give users access to the system.

That is inherent in this kind of restriction scheme. The user is authenticated to execute code in a certain security domain, and we are kludging in a restriction to limit that domain to a subdomain. For instance if you allow a user to run the vim command on a specific file to edit it, the user can just get a shell with :!sh[Enter].

How to call C++ function from C?

I would do it in the following way:

(If working with MSVC, ignore the GCC compilation commands)

Suppose that I have a C++ class named AAA, defined in files aaa.h, aaa.cpp, and that the class AAA has a method named sayHi(const char *name), that I want to enable for C code.

The C++ code of class AAA - Pure C++, I don't modify it:

aaa.h

#ifndef AAA_H
#define AAA_H

class AAA {
    public:
        AAA();
        void sayHi(const char *name);
};

#endif

aaa.cpp

#include <iostream>

#include "aaa.h"

AAA::AAA() {
}

void AAA::sayHi(const char *name) {
    std::cout << "Hi " << name << std::endl;
}

Compiling this class as regularly done for C++. This code "does not know" that it is going to be used by C code. Using the command:

g++ -fpic -shared aaa.cpp -o libaaa.so

Now, also in C++, creating a C connector. Defining it in files aaa_c_connector.h, aaa_c_connector.cpp. This connector is going to define a C function, named AAA_sayHi(cosnt char *name), that will use an instance of AAA and will call its method:

aaa_c_connector.h

#ifndef AAA_C_CONNECTOR_H 
#define AAA_C_CONNECTOR_H 

#ifdef __cplusplus
extern "C" {
#endif

void AAA_sayHi(const char *name);

#ifdef __cplusplus
}
#endif


#endif

aaa_c_connector.cpp

#include <cstdlib>

#include "aaa_c_connector.h"
#include "aaa.h"

#ifdef __cplusplus
extern "C" {
#endif

// Inside this "extern C" block, I can implement functions in C++, which will externally 
//   appear as C functions (which means that the function IDs will be their names, unlike
//   the regular C++ behavior, which allows defining multiple functions with the same name
//   (overloading) and hence uses function signature hashing to enforce unique IDs),


static AAA *AAA_instance = NULL;

void lazyAAA() {
    if (AAA_instance == NULL) {
        AAA_instance = new AAA();
    }
}

void AAA_sayHi(const char *name) {
    lazyAAA();
    AAA_instance->sayHi(name);
}

#ifdef __cplusplus
}
#endif

Compiling it, again, using a regular C++ compilation command:

g++ -fpic -shared aaa_c_connector.cpp -L. -laaa -o libaaa_c_connector.so

Now I have a shared library (libaaa_c_connector.so), that implements the C function AAA_sayHi(const char *name). I can now create a C main file and compile it all together:

main.c

#include "aaa_c_connector.h"

int main() {
    AAA_sayHi("David");
    AAA_sayHi("James");

    return 0;
}

Compiling it using a C compilation command:

gcc main.c -L. -laaa_c_connector -o c_aaa

I will need to set LD_LIBRARY_PATH to contain $PWD, and if I run the executable ./c_aaa, I will get the output I expect:

Hi David
Hi James

EDIT:

On some linux distributions, -laaa and -lstdc++ may also be required for the last compilation command. Thanks to @AlaaM. for the attention

How to play YouTube video in my Android application?

This answer could be really late, but its useful.

You can play youtube videos in the app itself using android-youtube-player.

Some code snippets:

To play a youtube video that has a video id in the url, you simply call the OpenYouTubePlayerActivity intent

Intent intent = new Intent(null, Uri.parse("ytv://"+v), this, 
            OpenYouTubePlayerActivity.class);
startActivity(intent);

where v is the video id.

Add the following permissions in the manifest file:

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>

and also declare this activity in the manifest file:

<activity 
        android:name="com.keyes.youtube.OpenYouTubePlayerActivity"></activity>

Further information can be obtained from the first portions of this code file.

Hope that helps anyone!

How to call jQuery function onclick?

Please have a look at http://jsfiddle.net/2dJAN/59/

$("#submit").click(function () {
var url = $(location).attr('href');
$('#spn_url').html('<strong>' + url + '</strong>');
});

How can I remove all text after a character in bash?

trim off everything after the last instance of ":"

cat fileListingPathsAndFiles.txt | grep -o '^.*:'

and if you wanted to drop that last ":"

cat file.txt | grep -o '^.*:' | sed 's/:$//'

@kp123: you'd want to replace : with / (where the sed colon should be \/)

Simple DatePicker-like Calendar

this datepicker is an excellent solution. datepickers are a must if you want to avoid code injection.

Transfer git repositories from GitLab to GitHub - can we, how to and pitfalls (if any)?

If you want to migrate the repo including the wiki and all issues and milestones, you can use node-gitlab-2-github and GitLab to GitHub migration

How to Set AllowOverride all

enter code hereif you are using linux you have to edit the

`/etc/apache2/sites-available/000-default.conf`

under the Documentroot . add the following code

`<Directory /var/www/>
  AllowOverride all
  Require all granted
</Directory>` 

then ,

`sudo service apache2 restart`

and you have to enable the apache mod rewrite

`sudo a2enmod rewrite`

JS Client-Side Exif Orientation: Rotate and Mirror JPEG Images

Wunderbart's post worked for me combined with statler's improvements. Adding a few more comments and syntax cleanup, and also passing back the orientation value and I have the following code feel free to use. Just call readImageFile() function below and you get back the transformed image and the original orientation.

const JpegOrientation = [
    "NOT_JPEG",
    "NORMAL",
    "FLIP-HORIZ",
    "ROT180",
    "FLIP-HORIZ-ROT180",
    "FLIP-HORIZ-ROT270",
    "ROT270",
    "FLIP-HORIZ-ROT90",
    "ROT90"
];


//Provided a image file, determines the orientation of the file based on the EXIF information.
//Calls the "callback" function with an index into the JpegOrientation array. 
//If the image is not a JPEG, returns 0. If  the orientation value cannot be read (corrupted file?) return -1.
function getOrientation(file, callback) {
    
    const reader = new FileReader();
    reader.onload = (e) => {

        const view = new DataView(e.target.result);
        
        if (view.getUint16(0, false) !== 0xFFD8) {
            return callback(0);  //NOT A JPEG FILE
        }
        
        const length = view.byteLength;
        let offset = 2;
        while (offset < length) {
            
            if (view.getUint16(offset+2, false) <= 8)   //unknown?
                return callback(-1);
            
            const marker = view.getUint16(offset, false);
            offset += 2;
            if (marker === 0xFFE1) {
                
                if (view.getUint32(offset += 2, false) !== 0x45786966) 
                    return callback(-1); //unknown?
                

                const little = view.getUint16(offset += 6, false) === 0x4949;
                offset += view.getUint32(offset + 4, little);
                const tags = view.getUint16(offset, little);
                offset += 2;
                for (var i = 0; i < tags; i++) {
                    if (view.getUint16(offset + (i * 12), little) === 0x0112) {
                        return callback(view.getUint16(offset + (i * 12) + 8, little));   //found orientation code
                    }
                }
            }
            else if ((marker & 0xFF00) !== 0xFF00) {
                break;
            }
            else { 
                offset += view.getUint16(offset, false);
            }
        }
        
        return callback(-1); //unknown?
    };
    reader.readAsArrayBuffer(file);
}

//Takes a jpeg image file as base64 and transforms it back to original, providing the
//transformed image in callback.  If the image is not a jpeg or is already in normal orientation,
//just calls the callback directly with the source.
//Set type to the desired output type if transformed, default is image/jpeg for speed.
function resetOrientation(srcBase64, srcOrientation, callback, type = "image/jpeg") {
    
    if (srcOrientation <= 1) {  //no transform needed
        callback(srcBase64);
        return;
    }
    
    const img = new Image();    

    img.onload = () => {
        const width = img.width;
        const height = img.height;
        const canvas = document.createElement('canvas');
        const ctx = canvas.getContext("2d");

        // set proper canvas dimensions before transform & export
        if (4 < srcOrientation && srcOrientation < 9) {
            canvas.width = height;
            canvas.height = width;
        } else {
            canvas.width = width;
            canvas.height = height;
        }

        // transform context before drawing image
        switch (srcOrientation) {
              
              //case 1: normal, no transform needed
              
              case 2:  
                  ctx.transform(-1, 0, 0, 1, width, 0); 
                  break;
              case 3:
                  ctx.transform(-1, 0, 0, -1, width, height); 
                  break;
              case 4: 
                  ctx.transform(1, 0, 0, -1, 0, height); 
                  break;
              case 5: 
                  ctx.transform(0, 1, 1, 0, 0, 0); 
                  break;
              case 6: 
                  ctx.transform(0, 1, -1, 0, height, 0); 
                  break;
              case 7: 
                  ctx.transform(0, -1, -1, 0, height, width); 
                  break;
              case 8: 
                  ctx.transform(0, -1, 1, 0, 0, width); 
                  break;
              default: 
                  break;
        }

        // draw image
        ctx.drawImage(img, 0, 0);

        //export base64
        callback(canvas.toDataURL(type), srcOrientation);
    };

    img.src = srcBase64;
};


//Read an image file, providing the returned data to callback. If the image is jpeg
//and is transformed according to EXIF info, transform it first.
//The callback function receives the image data and the orientation value (index into JpegOrientation)
export function readImageFile(file, callback) {

    getOrientation(file, (orientation) => {

        console.log("Read file \"" + file.name + "\" with orientation: " + JpegOrientation[orientation]);

        const reader = new FileReader();
        reader.onload = () => {  //when reading complete

            const img = reader.result;
            resetOrientation(img, orientation, callback);
        };
        reader.readAsDataURL(file);  //start read
        
    });
}

Rounding a variable to two decimal places C#

You should use a form of Math.Round. Be aware that Math.Round defaults to banker's rounding (rounding to the nearest even number) unless you specify a MidpointRounding value. If you don't want to use banker's rounding, you should use Math.Round(decimal d, int decimals, MidpointRounding mode), like so:

Math.Round(pay, 2, MidpointRounding.AwayFromZero); // .005 rounds up to 0.01
Math.Round(pay, 2, MidpointRounding.ToEven);       // .005 rounds to nearest even (0.00) 
Math.Round(pay, 2);    // Defaults to MidpointRounding.ToEven

(Why does .NET use banker's rounding?)

SVN (Subversion) Problem "File is scheduled for addition, but is missing" - Using Versions

Avoid using Xcode to rename files in a folder reference. If you rename a file using Xcode, it will be marked for commit. If you later delete it before the commit, you will end up with this error.

How to use sed/grep to extract text between two words?

This might work for you (GNU sed):

sed '/Here/!d;s//&\n/;s/.*\n//;:a;/String/bb;$!{n;ba};:b;s//\n&/;P;D' file 

This presents each representation of text between two markers (in this instance Here and String) on a newline and preserves newlines within the text.

append to url and refresh page

Please check the below code :

/*Get current URL*/    
var _url = location.href; 
/*Check if the url already contains ?, if yes append the parameter, else add the parameter*/
_url = ( _url.indexOf('?') !== -1 ) ? _url+'&param='+value : _url+'?param='+value;
/*reload the page */
window.location.href = _url;

Nodemailer with Gmail and NodeJS

For me is working this way, using port and security (I had issues to send emails from gmail using PHP without security settings)

I hope will help someone.

var sendEmail = function(somedata){
  var smtpConfig = {
    host: 'smtp.gmail.com',
    port: 465,
    secure: true, // use SSL, 
                  // you can try with TLS, but port is then 587
    auth: {
      user: '***@gmail.com', // Your email id
      pass: '****' // Your password
    }
  };

  var transporter = nodemailer.createTransport(smtpConfig);
  // replace hardcoded options with data passed (somedata)
  var mailOptions = {
    from: '[email protected]', // sender address
    to: '[email protected]', // list of receivers
    subject: 'Test email', // Subject line
    text: 'this is some text', //, // plaintext body
    html: '<b>Hello world ?</b>' // You can choose to send an HTML body instead
  }

  transporter.sendMail(mailOptions, function(error, info){
    if(error){
      return false;
    }else{
      console.log('Message sent: ' + info.response);
      return true;
    };
  });
}

exports.contact = function(req, res){
   // call sendEmail function and do something with it
   sendEmail(somedata);
}

all the config are listed here (including examples)

How to plot an array in python?

if you give a 2D array to the plot function of matplotlib it will assume the columns to be lines:

If x and/or y is 2-dimensional, then the corresponding columns will be plotted.

In your case your shape is not accepted (100, 1, 1, 8000). As so you can using numpy squeeze to solve the problem quickly:

np.squeez doc: Remove single-dimensional entries from the shape of an array.

import numpy as np
import matplotlib.pyplot as plt

data = np.random.randint(3, 7, (10, 1, 1, 80))
newdata = np.squeeze(data) # Shape is now: (10, 80)
plt.plot(newdata) # plotting by columns
plt.show()

But notice that 100 sets of 80 000 points is a lot of data for matplotlib. I would recommend that you look for an alternative. The result of the code example (run in Jupyter) is:

Jupyter matplotlib plot

Query to list all users of a certain group

And the more complex query if you need to search in a several groups:

(&(objectCategory=user)(|(memberOf=CN=GroupOne,OU=Security Groups,OU=Groups,DC=example,DC=com)(memberOf=CN=GroupTwo,OU=Security Groups,OU=Groups,DC=example,DC=com)(memberOf=CN=GroupThree,OU=Security Groups,OU=Groups,DC=example,DC=com)))

The same example with recursion:

(&(objectCategory=user)(|(memberOf:1.2.840.113556.1.4.1941:=CN=GroupOne,OU=Security Groups,OU=Groups,DC=example,DC=com)(memberOf:1.2.840.113556.1.4.1941:=CN=GroupTwo,OU=Security Groups,OU=Groups,DC=example,DC=com)(memberOf:1.2.840.113556.1.4.1941:=CN=GroupThree,OU=Security Groups,OU=Groups,DC=example,DC=com)))

First Heroku deploy failed `error code=H10`

In my case, I forgot to set database env for deployment. you can set env by this command (I'm using mLab for MongoDB server)

heroku config:set MONGO_URI='mongodb://address'

What is the proper way to test if a parameter is empty in a batch file?

I test with below code and it is fine.

@echo off

set varEmpty=
if not "%varEmpty%"=="" (
    echo varEmpty is not empty
) else (
    echo varEmpty is empty
)
set varNotEmpty=hasValue
if not "%varNotEmpty%"=="" (
    echo varNotEmpty is not empty
) else (
    echo varNotEmpty is empty
)

How to read AppSettings values from a .json file in ASP.NET Core

With .NET Core 2.2, and in the simplest way possible...

public IActionResult Index([FromServices] IConfiguration config)
{
    var myValue = config.GetValue<string>("MyKey");
}

appsettings.json is automatically loaded and available through either constructor or action injection, and there's a GetSection method on IConfiguration as well. There isn't any need to alter Startup.cs or Program.cs if all you need is appsettings.json.

Which font is used in Visual Studio Code Editor and how to change fonts?

Since the VisualStudio has been updated now (2019). You can try on this method:

  • Go to File->Preference->Settings.
  • Go to Workspace tab and then Text Editor->Font
  • Under Font-Family form, put the font-family names you want to use separated by a comma For e.g I have put these fonts in my Workspace: Click to see my Workspace setting

Capture event onclose browser

Events onunload or onbeforeunload you can't use directly - they do not differ between window close, page refresh, form submit, link click or url change.

The only working solution is How to capture the browser window close event?

How do I execute cmd commands through a batch file?

This fixes some issues with Blorgbeard's answer (but is untested):

@echo off
cd /d "c:\Program files\IIS Express"
start "" iisexpress /path:"C:\FormsAdmin.Site" /port:8088 /clr:v2.0
timeout 10
start http://localhost:8088/default.aspx
pause

Checking version of angular-cli that's installed?

You can use npm list -global to list all the component versions currently installed on your system.
For viewing specific lists at different levels use --depth.

e.g:

npm list -global --depth 0

Generate a dummy-variable

Another way is to use mtabulate from qdapTools package, i.e.

df <- data.frame(var = sample(c("A", "B", "C"), 5, replace = TRUE))
  var
#1   C
#2   A
#3   C
#4   B
#5   B

library(qdapTools)
mtabulate(df$var)

which gives,

  A B C
1 0 0 1
2 1 0 0
3 0 0 1
4 0 1 0
5 0 1 0

Accessing a Dictionary.Keys Key through a numeric index

A dictionary may not be very intuitive for using index for reference but, you can have similar operations with an array of KeyValuePair:

ex. KeyValuePair<string, string>[] filters;

Regex replace (in Python) - a simpler way?

I believe that the best idea is just to capture in a group whatever you want to replace, and then replace it by using the start and end properties of the captured group.

regards

Adrián

#the pattern will contain the expression we want to replace as the first group
pat = "word1\s(.*)\sword2"   
test = "word1 will never be a word2"
repl = "replace"

import re
m = re.search(pat,test)

if m and m.groups() > 0:
    line = test[:m.start(1)] + repl + test[m.end(1):]
    print line
else:
    print "the pattern didn't capture any text"

This will print: 'word1 will never be a word2'

The group to be replaced could be located in any position of the string.

Call a url from javascript

You can make an AJAX request if the url is in the same domain, e.g., same host different application. If so, I'd probably use a framework like jQuery, most likely the get method.

$.get('http://someurl.com',function(data,status) {
      ...parse the data...
},'html');

If you run into cross domain issues, then your best bet is to create a server-side action that proxies the request for you. Do your request to your server using AJAX, have the server request and return the response from the external host.

Thanks to@nickf, for pointing out the obvious problem with my original solution if the url is in a different domain.

Copy to Clipboard for all Browsers using javascript

I spent a lot of time looking for a solution to this problem too. Here's what i've found thus far:

If you want your users to be able to click on a button and copy some text, you may have to use Flash.

If you want your users to press Ctrl+C anywhere on the page, but always copy xyz to the clipboard, I wrote an all-JS solution in YUI3 (although it could easily be ported to other frameworks, or raw JS if you're feeling particularly self-loathing).

It involves creating a textbox off the screen which gets highlighted as soon as the user hits Ctrl/CMD. When they hit 'C' shortly after, they copy the hidden text. If they hit 'V', they get redirected to a container (of your choice) before the paste event fires.

This method can work well, because while you listen for the Ctrl/CMD keydown anywhere in the body, the 'A', 'C' or 'V' keydown listeners only attach to the hidden text box (and not the whole body). It also doesn't have to break the users expectations - you only get redirected to the hidden box if you had nothing selected to copy anyway!

Here's what i've got working on my site, but check http://at.cg/js/clipboard.js for updates if there are any:

YUI.add('clipboard', function(Y) {


// Change this to the id of the text area you would like to always paste in to:

pasteBox = Y.one('#pasteDIV');


// Make a hidden textbox somewhere off the page.

Y.one('body').append('<input id="copyBox" type="text" name="result" style="position:fixed; top:-20%;" onkeyup="pasteBox.focus()">');
copyBox = Y.one('#copyBox');


// Key bindings for Ctrl+A, Ctrl+C, Ctrl+V, etc:

// Catch Ctrl/Window/Apple keydown anywhere on the page.
Y.on('key', function(e) {
    copyData();
        //  Uncomment below alert and remove keyCodes after 'down:' to figure out keyCodes for other buttons.
        //  alert(e.keyCode);
        //  }, 'body',  'down:', Y);
}, 'body',  'down:91,224,17', Y);

// Catch V - BUT ONLY WHEN PRESSED IN THE copyBox!!!
Y.on('key', function(e) {
    // Oh no! The user wants to paste, but their about to paste into the hidden #copyBox!!
    // Luckily, pastes happen on keyPress (which is why if you hold down the V you get lots of pastes), and we caught the V on keyDown (before keyPress).
    // Thus, if we're quick, we can redirect the user to the right box and they can unload their paste into the appropriate container. phew.
    pasteBox.select();
}, '#copyBox',  'down:86', Y);

// Catch A - BUT ONLY WHEN PRESSED IN THE copyBox!!!
Y.on('key', function(e) {
    // User wants to select all - but he/she is in the hidden #copyBox! That wont do.. select the pasteBox instead (which is probably where they wanted to be).
    pasteBox.select();
}, '#copyBox',  'down:65', Y);



// What to do when keybindings are fired:

// User has pressed Ctrl/Meta, and is probably about to press A,C or V. If they've got nothing selected, or have selected what you want them to copy, redirect to the hidden copyBox!
function copyData() {
    var txt = '';
    // props to Sabarinathan Arthanari for sharing with the world how to get the selected text on a page, cheers mate!
        if (window.getSelection) { txt = window.getSelection(); }
        else if (document.getSelection) { txt = document.getSelection(); }
        else if (document.selection) { txt = document.selection.createRange().text; }
        else alert('Something went wrong and I have no idea why - please contact me with your browser type (Firefox, Safari, etc) and what you tried to copy and I will fix this immediately!');

    // If the user has nothing selected after pressing Ctrl/Meta, they might want to copy what you want them to copy. 
        if(txt=='') {
                copyBox.select();
        }
    // They also might have manually selected what you wanted them to copy! How unnecessary! Maybe now is the time to tell them how silly they are..?!
        else if (txt == copyBox.get('value')) {
        alert('This site uses advanced copy/paste technology, possibly from the future.\n \nYou do not need to select things manually - just press Ctrl+C! \n \n(Ctrl+V will always paste to the main box too.)');
                copyBox.select();
        } else {
                // They also might have selected something completely different! If so, let them. It's only fair.
        }
}
});

Hope someone else finds this useful :]

Remove HTML Tags from an NSString on the iPhone

Here's a blog post that discusses a couple of libraries available for stripping HTML http://sugarmaplesoftware.com/25/strip-html-tags/ Note the comments where others solutions are offered.

Why doesn't calling a Python string method do anything unless you assign its output?

Example for String Methods

Given a list of filenames, we want to rename all the files with extension hpp to the extension h. To do this, we would like to generate a new list called newfilenames, consisting of the new filenames. Fill in the blanks in the code using any of the methods you’ve learned thus far, like a for loop or a list comprehension.

filenames = ["program.c", "stdio.hpp", "sample.hpp", "a.out", "math.hpp", "hpp.out"]
# Generate newfilenames as a list containing the new filenames
# using as many lines of code as your chosen method requires.
newfilenames = []
for i in filenames:
    if i.endswith(".hpp"):
        x = i.replace("hpp", "h")
        newfilenames.append(x)
    else:
        newfilenames.append(i)


print(newfilenames)
# Should be ["program.c", "stdio.h", "sample.h", "a.out", "math.h", "hpp.out"]

Sublime Text 2 Code Formatting

I can't speak for the 2nd or 3rd, but if you install Node first, Sublime-HTMLPrettify works pretty well. You have to setup your own key shortcut once it is installed. One thing I noticed on Windows, you may need to edit your path for Node in the %PATH% variable if it is already long (I think the limit is 1024 for the %PATH% variable, and anything after that is ignored.)

There is a Windows bug, but in the issues there is a fix for it. You'll need to edit the HTMLPrettify.py file - https://github.com/victorporof/Sublime-HTMLPrettify/issues/12

Two Radio Buttons ASP.NET C#

     <asp:RadioButtonList id="RadioButtonList1" runat="server">
        <asp:ListItem Selected="True">Metric</asp:ListItem>
        <asp:ListItem>US</asp:ListItem>
     </asp:RadioButtonList>

How can I print out all possible letter combinations a given phone number can represent?

In Java using recursion:

import java.util.LinkedList;
import java.util.List;

public class Main {  
    // Number-to-letter mappings in order from zero to nine
    public static String mappings[][] = {
        {"0"}, {"1"}, {"A", "B", "C"}, {"D", "E", "F"}, {"G", "H", "I"},
        {"J", "K", "L"}, {"M", "N", "O"}, {"P", "Q", "R", "S"}, 
        {"T", "U", "V"}, {"W", "X", "Y", "Z"}
    };

    public static void generateCombosHelper(List<String> combos, 
            String prefix, String remaining) {
        // The current digit we are working with
        int digit = Integer.parseInt(remaining.substring(0, 1));

        if (remaining.length() == 1) {
            // We have reached the last digit in the phone number, so add 
            // all possible prefix-digit combinations to the list
            for (int i = 0; i < mappings[digit].length; i++) {
                combos.add(prefix + mappings[digit][i]);
            }
        } else {
            // Recursively call this method with each possible new 
            // prefix and the remaining part of the phone number.
            for (int i = 0; i < mappings[digit].length; i++) {
                generateCombosHelper(combos, prefix + mappings[digit][i], 
                        remaining.substring(1));
            }
        }
    }

    public static List<String> generateCombos(String phoneNumber) {
        // This will hold the final list of combinations
        List<String> combos = new LinkedList<String>();

        // Call the helper method with an empty prefix and the entire 
        // phone number as the remaining part.
        generateCombosHelper(combos, "", phoneNumber);

        return combos;
    }

    public static void main(String[] args) {
        String phone = "3456789";
        List<String> combos = generateCombos(phone);

        for (String s : combos) {
            System.out.println(s);
        }
    }
}

Multiple Order By with LINQ

You can use the ThenBy and ThenByDescending extension methods:

foobarList.OrderBy(x => x.Foo).ThenBy( x => x.Bar)

Kotlin's List missing "add", "remove", Map missing "put", etc?

You can do with create new one like this.

var list1 = ArrayList<Int>()
var list2  = list1.toMutableList()
list2.add(item)

Now you can use list2, Thank you.

How do I return the response from an asynchronous call?

Js is a single threaded.

Browser can be divided into three parts:

1)Event Loop

2)Web API

3)Event Queue

Event Loop runs for forever i.e kind of infinite loop.Event Queue is where all your function are pushed on some event(example:click) this is one by one carried out of queue and put into Event loop which execute this function and prepares it self for next one after first one is executed.This means Execution of one function doesn't starts till the function before it in queue is executed in event loop.

Now let us think we pushed two functions in a queue one is for getting a data from server and another utilises that data.We pushed the serverRequest() function in queue first then utiliseData() function. serverRequest function goes in event loop and makes a call to server as we never know how much time it will take to get data from server so this process is expected to take time and so we busy our event loop thus hanging our page, that's where Web API come into role it take this function from event loop and deals with server making event loop free so that we can execute next function from queue.The next function in queue is utiliseData() which goes in loop but because of no data available it goes waste and execution of next function continues till end of the queue.(This is called Async calling i.e we can do something else till we get data)

Let suppose our serverRequest() function had a return statement in a code, when we get back data from server Web API will push it in queue at the end of queue. As it get pushed at end in queue we cannot utilise its data as there is no function left in our queue to utilise this data.Thus it is not possible to return something from Async Call.

Thus Solution to this is callback or promise.

A Image from one of the answers here, Correctly explains callback use... We give our function(function utilising data returned from server) to function calling server.

CallBack

 function doAjax(callbackFunc, method, url) {
  var xmlHttpReq = new XMLHttpRequest();
  xmlHttpReq.open(method, url);
  xmlHttpReq.onreadystatechange = function() {

      if (xmlHttpReq.readyState == 4 && xmlHttpReq.status == 200) {
        callbackFunc(xmlHttpReq.responseText);
      }


  }
  xmlHttpReq.send(null);

}

In my Code it is called as

function loadMyJson(categoryValue){
  if(categoryValue==="veg")
  doAjax(print,"GET","http://localhost:3004/vegetables");
  else if(categoryValue==="fruits")
  doAjax(print,"GET","http://localhost:3004/fruits");
  else 
  console.log("Data not found");
}

Javscript.info callback

Test credit card numbers for use with PayPal sandbox

A bit late in the game but just in case it helps anyone.

If you are testing using the Sandbox and on the payment page you want to test payments NOT using a PayPal account but using the "Pay with Debit or Credit Card option" (i.e. when a regular Joe/Jane, NOT PayPal users, want to buy your stuff) and want to save yourself some time: just go to a site like http://www.getcreditcardnumbers.com/ and get numbers from there. You can use any Expiry date (in the future) and any numeric CCV (123 works).

The "test credit card numbers" in the PayPal documentation are just another brick in their infuriating wall of convoluted stuff.

I got the url above from PayPal's tech support.

Tested using a simple Hosted button and IPN. Good luck.

Rename all files in a folder with a prefix in a single command

Situation:

We have certificate.key certificate.crt inside /user/ssl/

We want to rename anything that starts with certificate to certificate_OLD

We are now located inside /user

First, you do a dry run with -n:

rename -n "s/certificate/certificate_old/" ./ssl/*

Which returns:

rename(./ssl/certificate.crt, ./ssl/certificate_OLD.crt) rename(./ssl/certificate.key, ./ssl/certificate_OLD.key)

Your files will be unchanged this is just a test run.

Solution:

When your happy with the result of the test run it for real:

rename "s/certificate/certificate_OLD/" ./ssl/*

What it means:

`rename "s/ SOMETHING / SOMETING_ELSE " PATH/FILES

Tip:

If you are already on the path run it like this:

rename "s/certificate/certificate_OLD/" *

Or if you want to do this in any sub-directory starting with ss do:

rename -n "s/certificat/certificate_old/" ./ss*/*

You can also do:

rename -n "s/certi*/certificate_old/" ./ss*/*

Which renames anything starting with certi in any sub-directory starting with ss.

The sky is the limit.

Play around with regex and ALWAYS test this BEFORE with -n.

WATCH OUT THIS WILL EVEN RENAME FOLDER NAMES THAT MATCH. Better cd into the directory and do it there. USE AT OWN RISK.

How to view data saved in android database(SQLite)?

If you don't want to download anything, you can use sqlite3 tool which is provided with adb :

Examining sqlite3 databases from a remote shell

and :

Command Line Shell For SQLite

Hadoop/Hive : Loading data from .csv on a local machine

You can load local CSV file to Hive only if:

  1. You are doing it from one of the Hive cluster nodes.
  2. You installed Hive client on non-cluster node and using hive or beeline for upload.

Stop Excel from automatically converting certain text values to dates

Okay found a simple way to do this in Excel 2003 through 2007. Open a blank xls workbook. Then go to Data menu, import external data. Select your csv file. Go through the wizard and then in "column data format" select any column that needs to be forced to "text". This will import that entire column as a text format preventing Excel from trying to treat any specific cells as a date.

Sticky and NON-Sticky sessions

When your website is served by only one web server, for each client-server pair, a session object is created and remains in the memory of the web server. All the requests from the client go to this web server and update this session object. If some data needs to be stored in the session object over the period of interaction, it is stored in this session object and stays there as long as the session exists.

However, if your website is served by multiple web servers which sit behind a load balancer, the load balancer decides which actual (physical) web-server should each request go to. For example, if there are 3 web servers A, B and C behind the load balancer, it is possible that www.mywebsite.com/index.jsp is served from server A, www.mywebsite.com/login.jsp is served from server B and www.mywebsite.com/accoutdetails.php are served from server C.

Now, if the requests are being served from (physically) 3 different servers, each server has created a session object for you and because these session objects sit on three independent boxes, there's no direct way of one knowing what is there in the session object of the other. In order to synchronize between these server sessions, you may have to write/read the session data into a layer which is common to all - like a DB. Now writing and reading data to/from a db for this use-case may not be a good idea. Now, here comes the role of sticky-session.

If the load balancer is instructed to use sticky sessions, all of your interactions will happen with the same physical server, even though other servers are present. Thus, your session object will be the same throughout your entire interaction with this website.

To summarize, In case of Sticky Sessions, all your requests will be directed to the same physical web server while in case of a non-sticky loadbalancer may choose any webserver to serve your requests.

As an example, you may read about Amazon's Elastic Load Balancer and sticky sessions here : http://aws.typepad.com/aws/2010/04/new-elastic-load-balancing-feature-sticky-sessions.html

How can I select all elements without a given class in jQuery?

You can use the .not() method or :not() selector

Code based on your example:

$("ul#list li").not(".active") // not method
$("ul#list li:not(.active)")   // not selector

How to delete a specific file from folder using asp.net

This is how I delete files

if ((System.IO.File.Exists(fileName)))
                {
                    System.IO.File.Delete(fileName);
}

Also make sure that the file name you are passing in your delete, is the accurate path

EDIT

You could use the following event instead as well or just use the code in this snippet and use in your method

void GridView1_SelectedIndexChanged(Object sender, EventArgs e)
  {

    // Get the currently selected row using the SelectedRow property.
    GridViewRow row = CustomersGridView.SelectedRow;

    //Debug this line and see what value is returned if it contains the full path.
    //If it does not contain the full path then add the path to the string.
    string fileName = row.Cells[0].Text 

    if(fileName != null || fileName != string.empty)
    {
       if((System.IO.File.Exists(fileName))
           System.IO.File.Delete(fileName);

     }
  }

filtering NSArray into a new NSArray in Objective-C

Assuming that your objects are all of a similar type you could add a method as a category of their base class that calls the function you're using for your criteria. Then create an NSPredicate object that refers to that method.

In some category define your method that uses your function

@implementation BaseClass (SomeCategory)
- (BOOL)myMethod {
    return someComparisonFunction(self, whatever);
}
@end

Then wherever you'll be filtering:

- (NSArray *)myFilteredObjects {
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"myMethod = TRUE"];
    return [myArray filteredArrayUsingPredicate:pred];
}

Of course, if your function only compares against properties reachable from within your class it may just be easier to convert the function's conditions to a predicate string.

How to Set/Update State of StatefulWidget from other StatefulWidget in Flutter?

enter image description here

This examples shows calling a method

  1. Defined in Child widget from Parent widget.
  2. Defined in Parent widget from Child widget.

class ParentPage extends StatefulWidget {
  @override
  _ParentPageState createState() => _ParentPageState();
}

class _ParentPageState extends State<ParentPage> {
  final GlobalKey<ChildPageState> _key = GlobalKey();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text("Parent")),
      body: Center(
        child: Column(
          children: <Widget>[
            Expanded(
              child: Container(
                color: Colors.grey,
                width: double.infinity,
                alignment: Alignment.center,
                child: RaisedButton(
                  child: Text("Call method in child"),
                  onPressed: () => _key.currentState.methodInChild(), // calls method in child
                ),
              ),
            ),
            Text("Above = Parent\nBelow = Child"),
            Expanded(
              child: ChildPage(
                key: _key,
                function: methodInParent,
              ),
            ),
          ],
        ),
      ),
    );
  }

  methodInParent() => Fluttertoast.showToast(msg: "Method called in parent", gravity: ToastGravity.CENTER);
}

class ChildPage extends StatefulWidget {
  final Function function;

  ChildPage({Key key, this.function}) : super(key: key);

  @override
  ChildPageState createState() => ChildPageState();
}

class ChildPageState extends State<ChildPage> {
  @override
  Widget build(BuildContext context) {
    return Container(
      color: Colors.teal,
      width: double.infinity,
      alignment: Alignment.center,
      child: RaisedButton(
        child: Text("Call method in parent"),
        onPressed: () => widget.function(), // calls method in parent
      ),
    );
  }

  methodInChild() => Fluttertoast.showToast(msg: "Method called in child");
}

Get Hours and Minutes (HH:MM) from date

Following code shows current hour and minutes in 'Hour:Minutes' column for us.

SELECT  CONVERT(VARCHAR(5), GETDATE(), 108) + 
(CASE WHEN DATEPART(HOUR, GETDATE()) > 12 THEN ' PM'
    ELSE ' AM'
END) 'Hour:Minutes'

or

SELECT  Format(GETDATE(), 'hh:mm') + 
(CASE WHEN DATEPART(HOUR, GETDATE()) > 12 THEN ' PM'
    ELSE ' AM'
END) 'Hour:Minutes'

Find a line in a file and remove it

You want to do something like the following:

  • Open the old file for reading
  • Open a new (temporary) file for writing
  • Iterate over the lines in the old file (probably using a BufferedReader)
    • For each line, check if it matches what you are supposed to remove
    • If it matches, do nothing
    • If it doesn't match, write it to the temporary file
  • When done, close both files
  • Delete the old file
  • Rename the temporary file to the name of the original file

(I won't write the actual code, since this looks like homework, but feel free to post other questions on specific bits that you have trouble with)

How do I get the HTML code of a web page in PHP?

you can use the DomDocument method to get an individual HTML tag level variable too

$homepage = file_get_contents('https://www.example.com/');
$doc = new DOMDocument;
$doc->loadHTML($homepage);
$titles = $doc->getElementsByTagName('h3');
echo $titles->item(0)->nodeValue;

make a phone call click on a button

For those using AppCompact...Try this

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.content.Intent;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import android.net.Uri;

public class MainActivity extends AppCompatActivity {



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button startBtn = (Button) findViewById(R.id.db);
        startBtn.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                makeCall();
            }
        });

    }

    protected void makeCall() {
        EditText num = (EditText)findViewById(R.id.Dail);
        String phone = num.getText().toString();
        String d = "tel:" + phone ;
        Log.i("Make call", "");
        Intent phoneIntent = new Intent(Intent.ACTION_CALL);
        phoneIntent.setData(Uri.parse(d));
        try {
            startActivity(phoneIntent);
            finish();
            Log.i("Finished making a call", "");
        } catch (android.content.ActivityNotFoundException ex) {
            Toast.makeText(this, "Call faild, please try again later.", Toast.LENGTH_SHORT).show();
        }
    }

}

Then add this to your manifest,,,

 <uses-permission android:name="android.permission.CALL_PHONE" />

Hibernate dialect for Oracle Database 11g?

Use the Oracle 10g dialect. Also Hibernate 3.3.2+ is required for recent JDBC drivers (the internal class structure changed - symptoms will be whining about an abstract class).

Dialect of Oracle 11g is same as Oracle 10g (org.hibernate.dialect.Oracle10gDialect). Source: http://docs.jboss.org/hibernate/orm/3.6/reference/en-US/html/session-configuration.html#configuration-optional-dialects

How to automatically generate getters and setters in Android Studio

Android Studio & OSx :

Press cmd+n > Generate > Getter and Setter

Android Studio & Windows :

Press Alt + Insert > Generate > Getter and Setter

How do I close a tkinter window?

There is a simple one-line answer:

Write - exit() in the command

That's it!

Proper way to catch exception from JSON.parse

i post something into an iframe then read back the contents of the iframe with json parse...so sometimes it's not a json string

Try this:

if(response) {
    try {
        a = JSON.parse(response);
    } catch(e) {
        alert(e); // error in the above string (in this case, yes)!
    }
}

error C2220: warning treated as error - no 'object' file generated

Go to project properties -> configurations properties -> C/C++ -> treats warning as error -> No (/WX-).

jQuery Ajax Request inside Ajax Request

$.ajax({
    url: "<?php echo site_url('upToWeb/ajax_edit/')?>/" + id,
    type: "GET",
    dataType: "JSON",
    success: function (data) {
        if (data.web == 0) {
            if (confirm('Data product upToWeb ?')) {
                $.ajax({
                    url: "<?php echo site_url('upToWeb/set_web/')?>/" + data.id_item,
                    type: "post",
                    dataType: "json",
                    data: {web: 1},
                    success: function (respons) {
                        location.href = location.pathname;
                    },
                    error: function (xhr, ajaxOptions, thrownError) { // Ketika terjadi error
                        alert(xhr.responseText); // munculkan alert
                    }
                });
            }
        }
        else {
            if (confirm('Data product DownFromWeb ?')) {
                $.ajax({
                    url: "<?php echo site_url('upToWeb/set_web/')?>/" + data.id_item,
                    type: "post",
                    dataType: "json",
                    data: {web: 0},
                    success: function (respons) {
                        location.href = location.pathname;
                    },
                    error: function (xhr, ajaxOptions, thrownError) { // Ketika terjadi error
                        alert(xhr.responseText); // munculkan alert
                    }
                });
            }
        }
    },

    error: function (jqXHR, textStatus, errorThrown) {
        alert('Error get data from ajax');
    }

});

PowerShell - Start-Process and Cmdline Switches

Unless the OP is using PowerShell Community Extensions which does provide a Start-Process cmdlet along with a bunch of others. If this the case then Glennular's solution works a treat since it matches the positional parameters of pscx\start-process : -path (position 1) -arguments (positon 2).

Could not load type 'System.Runtime.CompilerServices.ExtensionAttribute' from assembly 'mscorlib

Could not load type 'System.Runtime.CompilerServices.ExtensionAttribute' from assembly mscorlib

Yes, this technically can go wrong when you execute code on .NET 4.0 instead of .NET 4.5. The attribute was moved from System.Core.dll to mscorlib.dll in .NET 4.5. While that sounds like a rather nasty breaking change in a framework version that is supposed to be 100% compatible, a [TypeForwardedTo] attribute is supposed to make this difference unobservable.

As Murphy would have it, every well intended change like this has at least one failure mode that nobody thought of. This appears to go wrong when ILMerge was used to merge several assemblies into one and that tool was used incorrectly. A good feedback article that describes this breakage is here. It links to a blog post that describes the mistake. It is rather a long article, but if I interpret it correctly then the wrong ILMerge command line option causes this problem:

  /targetplatform:"v4,c:\windows\Microsoft.NET\Framework\v4.0.30319"

Which is incorrect. When you install 4.5 on the machine that builds the program then the assemblies in that directory are updated from 4.0 to 4.5 and are no longer suitable to target 4.0. Those assemblies really shouldn't be there anymore but were kept for compat reasons. The proper reference assemblies are the 4.0 reference assemblies, stored elsewhere:

  /targetplatform:"v4,C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0"

So possible workarounds are to fall back to 4.0 on the build machine, install .NET 4.5 on the target machine and the real fix, to rebuild the project from the provided source code, fixing the ILMerge command.


Do note that this failure mode isn't exclusive to ILMerge, it is just a very common case. Any other scenario where these 4.5 assemblies are used as reference assemblies in a project that targets 4.0 is liable to fail the same way. Judging from other questions, another common failure mode is in build servers that were setup without using a valid VS license. And overlooking that the multi-targeting packs are a free download.

Using the reference assemblies in the c:\program files (x86) subdirectory is a rock hard requirement. Starting at .NET 4.0, already important to avoid accidentally taking a dependency on a class or method that was added in the 4.01, 4.02 and 4.03 releases. But absolutely essential now that 4.5 is released.

Re-ordering factor levels in data frame

Assuming your dataframe is mydf:

mydf$task <- factor(mydf$task, levels = c("up", "down", "left", "right", "front", "back"))

How do I determine if a port is open on a Windows server?

If telnet is not available, download PuTTY. It is a far superior Telnet, SSH, etc. client and will be useful in many situations, not just this one, especially if you are administering a server.

Check if certain value is contained in a dataframe column in pandas

You can simply use this:

'07311954' in df.date.values which returns True or False


Here is the further explanation:

In pandas, using in check directly with DataFrame and Series (e.g. val in df or val in series ) will check whether the val is contained in the Index.

BUT you can still use in check for their values too (instead of Index)! Just using val in df.col_name.values or val in series.values. In this way, you are actually checking the val with a Numpy array.

And .isin(vals) is the other way around, it checks whether the DataFrame/Series values are in the vals. Here vals must be set or list-like. So this is not the natural way to go for the question.

How to loop through a directory recursively to delete files with certain extensions

If you want to do something recursively, I suggest you use recursion (yes, you can do it using stacks and so on, but hey).

recursiverm() {
  for d in *; do
    if [ -d "$d" ]; then
      (cd -- "$d" && recursiverm)
    fi
    rm -f *.pdf
    rm -f *.doc
  done
}

(cd /tmp; recursiverm)

That said, find is probably a better choice as has already been suggested.

What is code coverage and how do YOU measure it?

Code coverage is a measurement of how many lines/blocks/arcs of your code are executed while the automated tests are running.

Code coverage is collected by using a specialized tool to instrument the binaries to add tracing calls and run a full set of automated tests against the instrumented product. A good tool will give you not only the percentage of the code that is executed, but also will allow you to drill into the data and see exactly which lines of code were executed during a particular test.

Our team uses Magellan - an in-house set of code coverage tools. If you are a .NET shop, Visual Studio has integrated tools to collect code coverage. You can also roll some custom tools, like this article describes.

If you are a C++ shop, Intel has some tools that run for Windows and Linux, though I haven't used them. I've also heard there's the gcov tool for GCC, but I don't know anything about it and can't give you a link.

As to how we use it - code coverage is one of our exit criteria for each milestone. We have actually three code coverage metrics - coverage from unit tests (from the development team), scenario tests (from the test team) and combined coverage.

BTW, while code coverage is a good metric of how much testing you are doing, it is not necessarily a good metric of how well you are testing your product. There are other metrics you should use along with code coverage to ensure the quality.

How to pass a callback as a parameter into another function

If you google for javascript callback function example you will get Getting a better understanding of callback functions in JavaScript

This is how to do a callback function:

function f() {
    alert('f was called!');
}

function callFunction(func) {
    func();
}

callFunction(f);

Simulate user input in bash script

You should find the 'expect' command will do what you need it to do. Its widely available. See here for an example : http://www.thegeekstuff.com/2010/10/expect-examples/

(very rough example)

#!/usr/bin/expect
set pass "mysecret"

spawn /usr/bin/passwd

expect "password: "
send "$pass"
expect "password: "
send "$pass"

Bootstrap 3 collapsed menu doesn't close on click

I had the similar issue but mine wouldn't stay open it would open/close quickly, I found that I had jquery-1.11.1.min.js loading before bootstrap.min.js. So I reversed the order of those 2 files and fixed my menu. Runs flawlessly now. Hope it helps

How do I set up curl to permanently use a proxy?

Curl will look for a .curlrc file in your home folder when it starts. You can create (or edit) this file and add this line:

proxy = yourproxy.com:8080

cancelling a handler.postdelayed process

Another way is to handle the Runnable itself:

Runnable r = new Runnable {
    public void run() {
        if (booleanCancelMember != false) {
            //do what you need
        }
    }
}

Link a .css on another folder

_x000D_
_x000D_
<link rel="stylesheet" type="text/css" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
_x000D_
.tree-view-com ul li {_x000D_
  position: relative;_x000D_
  list-style: none;_x000D_
}_x000D_
.tree-view-com .tree-view-child > li{_x000D_
  padding-bottom: 30px;_x000D_
}_x000D_
.tree-view-com .tree-view-child > li:last-of-type{_x000D_
  padding-bottom: 0px;_x000D_
}_x000D_
 _x000D_
.tree-view-com ul li a .c-icon {_x000D_
  margin-right: 10px;_x000D_
  position: relative;_x000D_
  top: 2px;_x000D_
}_x000D_
.tree-view-com ul > li > ul {_x000D_
  margin-top: 20px;_x000D_
  position: relative;_x000D_
}_x000D_
.tree-view-com > ul > li:before {_x000D_
  content: "";_x000D_
  border-left: 1px dashed #ccc;_x000D_
  position: absolute;_x000D_
  height: calc(100% - 30px - 5px);_x000D_
  z-index: 1;_x000D_
  left: 8px;_x000D_
  top: 30px;_x000D_
}_x000D_
.tree-view-com > ul > li > ul > li:before {_x000D_
  content: "";_x000D_
  border-top: 1px dashed #ccc;_x000D_
  position: absolute;_x000D_
  width: 25px;_x000D_
  left: -32px;_x000D_
  top: 12px;_x000D_
}
_x000D_
<div class="tree-view-com">_x000D_
    <ul class="tree-view-parent">_x000D_
        <li>_x000D_
            <a href=""><i class="fa fa-folder c-icon c-icon-list" aria-hidden="true"></i> folder</a>_x000D_
            <ul class="tree-view-child">_x000D_
                <li>_x000D_
                    <a href="" class="document-title">_x000D_
                        <i class="fa fa-folder c-icon" aria-hidden="true"></i>_x000D_
                        sub folder 1_x000D_
                    </a>_x000D_
                </li>_x000D_
                <li>_x000D_
                    <a href="" class="document-title">_x000D_
                        <i class="fa fa-folder c-icon" aria-hidden="true"></i>_x000D_
                        sub folder 2_x000D_
                    </a>_x000D_
                </li>_x000D_
                <li>_x000D_
                    <a href="" class="document-title">_x000D_
                        <i class="fa fa-folder c-icon" aria-hidden="true"></i>_x000D_
                        sub folder 3_x000D_
                    </a>_x000D_
                </li>_x000D_
            </ul>_x000D_
        </li>_x000D_
    </ul>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Forcing to download a file using PHP

A previous answer on this page describes how to use .htaccess to force all files of a certain type to download. However, the solution does not work with all file types across all browsers. This is a more reliable way:

<FilesMatch "\.(?i:csv)$">
  ForceType application/octet-stream
  Header set Content-Disposition attachment
</FilesMatch>

You might need to flush your browser cache to see this working correctly.

What is the difference between class and instance methods?

Also remember, the same idea applies to variables. You will come across terms like static, member, instance, class and so on when talking about variables the same as you would for methods/functions.

It seems the common term in the Obj-C community is ivar for instance variable, but I am not an Obj-C guy, yet.

How do I change the background of a Frame in Tkinter?

The root of the problem is that you are unknowingly using the Frame class from the ttk package rather than from the tkinter package. The one from ttk does not support the background option.

This is the main reason why you shouldn't do global imports -- you can overwrite the definition of classes and commands.

I recommend doing imports like this:

import tkinter as tk
import ttk

Then you prefix the widgets with either tk or ttk :

f1 = tk.Frame(..., bg=..., fg=...)
f2 = ttk.Frame(..., style=...)

It then becomes instantly obvious which widget you are using, at the expense of just a tiny bit more typing. If you had done this, this error in your code would never have happened.

Javascript use variable as object name

I think Shaz's answer for local variables is hard to understand, though it works for non-recursive functions. Here's another way that I think it's clearer (but it's still his idea, exact same behavior). It's also not accessing the local variables dynamically, just the property of the local variable.

Essentially, it's using a global variable (attached to the function object)

// Here's  a version of it that is more straight forward.
function doIt() {
    doIt.objname = {};
    var someObject = "objname";
    doIt[someObject].value = "value";    
    console.log(doIt.objname);
})();

Which is essentially the same thing as creating a global to store the variable, so you can access it as a property. Creating a global to do this is such a hack.

Here's a cleaner hack that doesn't create global variables, it uses a local variable instead.

function doIt() {
  var scope = {
     MyProp: "Hello"
  };
  var name = "MyProp";
  console.log(scope[name]);
}

See Javascript: interpret string as object reference?

How to simulate target="_blank" in JavaScript

You can extract the href from the a tag:

window.open(document.getElementById('redirect').href);

Credentials for the SQL Server Agent service are invalid

I've had this error as a result of trying to use a cloned VM that had the same SID as the domain. The two options to fix it were: sysprep (or rebuild) the database server OR dcpromo the DC down and back up to change the domain SID.

Extension methods must be defined in a non-generic static class

Extension method should be inside a static class. So please add your extension method inside a static class.

so for example it should be like this

public static class myclass
    {
        public static Byte[] ToByteArray(this Stream stream)
        {
            Int32 length = stream.Length > Int32.MaxValue ? Int32.MaxValue : Convert.ToInt32(stream.Length);
            Byte[] buffer = new Byte[length];
            stream.Read(buffer, 0, length);
            return buffer;
        }

    }

Does JSON syntax allow duplicate keys in an object?

Asking for purpose, there are different answers:

Using JSON to serialize objects (JavaScriptObjectNotation), each dictionary element maps to an indivual object property, so different entries defining a value for the same property has no meaning.

However, I came over the same question from a very specific use case: Writing JSON samples for API testing, I was wondering how to add comments into our JSON file without breaking the usability. The JSON spec does not know comments, so I came up with a very simple approach:

To use duplicate keys to comment our JSON samples. Example:

{ "property1" : "value1", "REMARK" : "... prop1 controls ...", "property2" : "value2", "REMARK" : "... value2 raises an exception ...", }

The JSON serializers which we are using have no problems with these "REMARK" duplicates and our application code simply ignores this little overhead.

So, even though there is no meaning on the application layer, these duplicates for us provide a valuable workaround to add comments to our testing samples without breaking the usability of the JSON.

undefined reference to WinMain@16 (codeblocks)

  1. You need to open the project file of your program and it should appear on Management panel.

  2. Right click on the project file, then select add file. You should add the 3 source code (secrypt.h, secrypt.cpp, and the trial.cpp)

  3. Compile and enjoy. Hope, I could help you.

How can I declare and use Boolean variables in a shell script?

Revised Answer (Feb 12, 2014)

the_world_is_flat=true
# ...do something interesting...
if [ "$the_world_is_flat" = true ] ; then
    echo 'Be careful not to fall off!'
fi

Original Answer

Caveats: https://stackoverflow.com/a/21210966/89391

the_world_is_flat=true
# ...do something interesting...
if $the_world_is_flat ; then
    echo 'Be careful not to fall off!'
fi

From: Using boolean variables in Bash

The reason the original answer is included here is because the comments before the revision on Feb 12, 2014 pertain only to the original answer, and many of the comments are wrong when associated with the revised answer. For example, Dennis Williamson's comment about bash builtin true on Jun 2, 2010 only applies to the original answer, not the revised.

Android Pop-up message

You can use Dialog to create this easily

create a Dialog instance using the context

Dialog dialog = new Dialog(contex);

You can design your layout as you like.

You can add this layout to your dialog by dialog.setContentView(R.layout.popupview);//popup view is the layout you created

then you can access its content (textviews, etc.) by using findViewById method

TextView txt = (TextView)dialog.findViewById(R.id.textbox);

you can add any text here. the text can be stored in the String.xml file in res\values.

txt.setText(getString(R.string.message));

then finally show the pop up menu

dialog.show();

more information http://developer.android.com/guide/topics/ui/dialogs.html

http://developer.android.com/reference/android/app/Dialog.html

Hibernate: How to set NULL query-parameter value with HQL?

For an actual HQL query:

FROM Users WHERE Name IS NULL

How to set up a Web API controller for multipart/form-data

check ur WebApiConfig and add this

GlobalConfiguration.Configuration.Formatters.XmlFormatter.SupportedMediaTypes.Clear();

How do I declare a namespace in JavaScript?

Sample:

var namespace = {};
namespace.module1 = (function(){

    var self = {};
    self.initialized = false;

    self.init = function(){
        setTimeout(self.onTimeout, 1000)
    };

    self.onTimeout = function(){
        alert('onTimeout')
        self.initialized = true;
    };

    self.init(); /* If it needs to auto-initialize, */
    /* You can also call 'namespace.module1.init();' from outside the module. */
    return self;
})()

You can optionally declare a local variable, same, like self and assign local.onTimeout if you want it to be private.

How do you read scanf until EOF in C?

I guess best way to do this is ...

int main()
{
    char str[100];
    scanf("[^EOF]",str);
    printf("%s",str);
    return 0;     
}

Removing trailing newline character from fgets() input

size_t ln = strlen(name) - 1;
if (*name && name[ln] == '\n') 
    name[ln] = '\0';

How to include a PHP variable inside a MySQL statement

That's the easy answer:

$query="SELECT * FROM CountryInfo WHERE Name = '".$name."'";

and you define $name whatever you want.
And another way, the complex way, is like that:

$query = " SELECT '" . $GLOBALS['Name'] . "' .* " .
         " FROM CountryInfo " .
         " INNER JOIN District " .
         " ON District.CountryInfoId = CountryInfo.CountryInfoId " .
         " INNER JOIN City " .
         " ON City.DistrictId = District.DistrictId " .
         " INNER JOIN '" . $GLOBALS['Name'] . "' " .
         " ON '" . $GLOBALS['Name'] . "'.CityId = City.CityId " .
         " WHERE CountryInfo.Name = '" . $GLOBALS['CountryName'] .
         "'";

Setting an int to Infinity in C++

Integers are inherently finite. The closest you can get is by setting a to int's maximum value:

#include <limits>

// ...

int a = std::numeric_limits<int>::max();

Which would be 2^31 - 1 (or 2 147 483 647) if int is 32 bits wide on your implementation.

If you really need infinity, use a floating point number type, like float or double. You can then get infinity with:

double a = std::numeric_limits<double>::infinity();

How to parse data in JSON format?

Following is simple example that may help you:

json_string = """
{
    "pk": 1, 
    "fa": "cc.ee", 
    "fb": {
        "fc": "", 
        "fd_id": "12345"
    }
}"""

import json
data = json.loads(json_string)
if data["fa"] == "cc.ee":
    data["fb"]["new_key"] = "cc.ee was present!"

print json.dumps(data)

The output for the above code will be:

{"pk": 1, "fb": {"new_key": "cc.ee was present!", "fd_id": "12345", 
 "fc": ""}, "fa": "cc.ee"}

Note that you can set the ident argument of dump to print it like so (for example,when using print json.dumps(data , indent=4)):

{
    "pk": 1, 
    "fb": {
        "new_key": "cc.ee was present!", 
        "fd_id": "12345", 
        "fc": ""
    }, 
    "fa": "cc.ee"
}

Create a map with clickable provinces/states using SVG, HTML/CSS, ImageMap

Sounds like you want a simple imagemap, I'd recommend to not make it more complex than it needs to be. Here's an article on how to improve imagemaps with svg. It's very easy to do clickable regions in svg itself, just add some <a> elements around the shapes you want to have clickable.

A couple of options if you need something more advanced:

Add Custom Headers using HttpWebRequest

IMHO it is considered as malformed header data.

You actually want to send those name value pairs as the request content (this is the way POST works) and not as headers.

The second way is true.

Should a function have only one return statement?

I lean towards using guard clauses to return early and otherwise exit at the end of a method. The single entry and exit rule has historical significance and was particularly helpful when dealing with legacy code that ran to 10 A4 pages for a single C++ method with multiple returns (and many defects). More recently, accepted good practice is to keep methods small which makes multiple exits less of an impedance to understanding. In the following Kronoz example copied from above, the question is what occurs in //Rest of code...?:

void string fooBar(string s, int? i) {

  if(string.IsNullOrEmpty(s) || i == null) return null;

  var res = someFunction(s, i);

  foreach(var r in res) {
      if(!r.Passed) return null;
  }

  // Rest of code...

  return ret;
}

I realise the example is somewhat contrived but I would be tempted to refactor the foreach loop into a LINQ statement that could then be considered a guard clause. Again, in a contrived example the intent of the code isn't apparent and someFunction() may have some other side effect or the result may be used in the // Rest of code....

if (string.IsNullOrEmpty(s) || i == null) return null;
if (someFunction(s, i).Any(r => !r.Passed)) return null;

Giving the following refactored function:

void string fooBar(string s, int? i) {

  if (string.IsNullOrEmpty(s) || i == null) return null;
  if (someFunction(s, i).Any(r => !r.Passed)) return null;

  // Rest of code...

  return ret;
}

What is the difference between a candidate key and a primary key?

John Woo's answer is correct, as far as it goes. Here are a few additional points.

A primary key is always one of the candidate keys. Fairly often, it's the only candidate.

A table with no candidate keys does not represent a relation. If you're using the relational model to help you build a good database, then every table you design will have at least one candidate key.

The relational model would be complete without the concept of primary key. It wasn't in the original presentation of the relational model. As a practical matter, the use of foreign key references without a declared primary key leads to a mess. It could be a logically correct mess, but it's a mess nonetheless. Declaring a primary key lets the DBMS help you enforce the data rules. Most of the time, having the DBMS help you enforce the data rules is a good thing, and well worth the cost.

Some database designers and some users have some mental confusion about whether the primary key identifies a row (record) in a table or an instance of an entity in the subject matter that the table represents. In an ideal world, it's supposed to do both, and there should be a one-for-one correspondence between rows in an entity table and instances of the corresponding entity.

In the real world, things get screwed up. Somebody enters the same new employee twice, and the employee ends up with two ids. Somebody gets hired, but the data entry slips through the cracks in some manual process, and the employee doesn't get an id, until the omission is corrected. A database that does not collapse the first time things get screwed up is more robust than one that does.

Django: Calling .update() on a single model instance retrieved by .get()?

Here's a mixin that you can mix into any model class which gives each instance an update method:

class UpdateMixin(object):
    def update(self, **kwargs):
        if self._state.adding:
            raise self.DoesNotExist
        for field, value in kwargs.items():
            setattr(self, field, value)
        self.save(update_fields=kwargs.keys())

The self._state.adding check checks to see if the model is saved to the database, and if not, raises an error.

(Note: This update method is for when you want to update a model and you know the instance is already saved to the database, directly answering the original question. The built-in update_or_create method featured in Platinum Azure's answer already covers the other use-case.)

You would use it like this (after mixing this into your user model):

user = request.user
user.update(favorite_food="ramen")

Besides having a nicer API, another advantage to this approach is that it calls the pre_save and post_save hooks, while still avoiding atomicity issues if another process is updating the same model.

newline character in c# string

They might be just a \r or a \n. I just checked and the text visualizer in VS 2010 displays both as newlines as well as \r\n.

This string

string test = "blah\r\nblah\rblah\nblah";

Shows up as

blah
blah
blah
blah

in the text visualizer.

So you could try

string modifiedString = originalString
    .Replace(Environment.NewLine, "<br />")
    .Replace("\r", "<br />")
    .Replace("\n", "<br />");

Is calculating an MD5 hash less CPU intensive than SHA family functions?

MD5 also benefits from SSE2 usage, check out BarsWF and then tell me that it doesn't. All it takes is a little assembler knowledge and you can craft your own MD5 SSE2 routine(s). For large amounts of throughput however, there is a tradeoff of the speed during hashing as opposed to the time spent rearranging the input data to be compatible with the SIMD instructions used.

What are all the different ways to create an object in Java?

There are five different ways to create an object in Java,

1. Using new keyword ? constructor get called

Employee emp1 = new Employee();

2. Using newInstance() method of Class ? constructor get called

Employee emp2 = (Employee) Class.forName("org.programming.mitra.exercises.Employee")
                                .newInstance();

It can also be written as

Employee emp2 = Employee.class.newInstance();

3. Using newInstance() method of Constructor ? constructor get called

Constructor<Employee> constructor = Employee.class.getConstructor();
Employee emp3 = constructor.newInstance();

4. Using clone() method ? no constructor call

Employee emp4 = (Employee) emp3.clone();

5. Using deserialization ? no constructor call

ObjectInputStream in = new ObjectInputStream(new FileInputStream("data.obj"));
Employee emp5 = (Employee) in.readObject();

First three methods new keyword and both newInstance() include a constructor call but later two clone and deserialization methods create objects without calling the constructor.

All above methods have different bytecode associated with them, Read Different ways to create objects in Java with Example for examples and more detailed description e.g. bytecode conversion of all these methods.

However one can argue that creating an array or string object is also a way of creating the object but these things are more specific to some classes only and handled directly by JVM, while we can create an object of any class by using these 5 ways.

How to POST the data from a modal form of Bootstrap?

You need to handle it via ajax submit.

Something like this:

$(function(){
    $('#subscribe-email-form').on('submit', function(e){
        e.preventDefault();
        $.ajax({
            url: url, //this is the submit URL
            type: 'GET', //or POST
            data: $('#subscribe-email-form').serialize(),
            success: function(data){
                 alert('successfully submitted')
            }
        });
    });
});

A better way would be to use a django form, and then render the following snippet:

<form>
    <div class="modal-body">
        <input type="email" placeholder="email"/>
        <p>This service will notify you by email should any issue arise that affects your plivo service.</p>
    </div>
    <div class="modal-footer">
        <input type="submit" value="SUBMIT" class="btn"/>
    </div>
</form>

via the context - example : {{form}}.

How to delete multiple values from a vector?

You can use setdiff.

Given

a <- sample(1:10)
remove <- c(2, 3, 5)

Then

> a
 [1] 10  8  9  1  3  4  6  7  2  5
> setdiff(a, remove)
[1] 10  8  9  1  4  6  7

error LNK2005: xxx already defined in MSVCRT.lib(MSVCR100.dll) C:\something\LIBCMT.lib(setlocal.obj)

If you VS solution contains several projects, select all of them in the right pane, and press "properties". Then go to C++ -> Code Generation and chose one Run Time library option for all of them

How can I find the product GUID of an installed MSI setup?

There is also a very helpful GUI tool called Product Browser which appears to be made by Microsoft or at least an employee of Microsoft.

It can be found on Github here Product Browser

I personally had a very easy time locating the GUID I needed with this.

How can I rollback an UPDATE query in SQL server 2005?

As already stated there is nothing you can do except restore from a backup. At least now you will have learned to always wrap statements in a transaction to see what happens before you decide to commit. Also, if you don't have a backup of your database this will also teach you to make regular backups of your database.

While we haven't been much help for your imediate problem...hopefully these answers will ensure you don't run into this problem again in the future.

Delete directory with files in it?

2 cents to add to THIS answer above, which is great BTW

After your glob (or similar) function has scanned/read the directory, add a conditional to check the response is not empty, or an invalid argument supplied for foreach() warning will be thrown. So...

if( ! empty( $files ) )
{
    foreach( $files as $file )
    {
        // do your stuff here...
    }
}

My full function (as an object method):

    private function recursiveRemoveDirectory( $directory )
    {
        if( ! is_dir( $directory ) )
        {
            throw new InvalidArgumentException( "$directory must be a directory" );
        }

        if( substr( $directory, strlen( $directory ) - 1, 1 ) != '/' )
        {
            $directory .= '/';
        }

        $files = glob( $directory . "*" );

        if( ! empty( $files ) )
        {
            foreach( $files as $file )
            {
                if( is_dir( $file ) )
                {
                    $this->recursiveRemoveDirectory( $file );
                }
                else
                {
                    unlink( $file );
                }
            }               
        }
        rmdir( $directory );

    } // END recursiveRemoveDirectory()

No tests found with test runner 'JUnit 4'

In my case the issue was the generics parameters:

public class TestClass<T extends Serializable> {

removing :

<T extends Serializable>

and the option was available again.

I'm using Junit4

increase legend font size ggplot2

You can also specify the font size relative to the base_size included in themes such as theme_bw() (where base_size is 11) using the rel() function.

For example:

ggplot(mtcars, aes(disp, mpg, col=as.factor(cyl))) +
  geom_point() +
  theme_bw() +
  theme(legend.text=element_text(size=rel(0.5)))

Setting Column width in Apache POI

With Scala there is a nice Wrapper spoiwo

You can do it like this:

Workbook(mySheet.withColumns(
      Column(autoSized = true),
      Column(width = new Width(100, WidthUnit.Character)),
      Column(width = new Width(100, WidthUnit.Character)))
    )

Use grep --exclude/--include syntax to not grep through certain files

Please take a look at ack, which is designed for exactly these situations. Your example of

grep -ircl --exclude=*.{png,jpg} "foo=" *

is done with ack as

ack -icl "foo="

because ack never looks in binary files by default, and -r is on by default. And if you want only CPP and H files, then just do

ack -icl --cpp "foo="

How to export a MySQL database to JSON?

as described in the link, it only returns (as I mentioned) 15 results. (fwiw, I checked these results against the 4000 I'm supposed to get, and these 15 are the same as the first 15 of the 4000)

That's because mysql restricts the length of the data returned by group concat to the value set in @@group_concat_max_len as soon as it gets to the that amount it truncates and returns what it's gotten so far.

You can set @@group_concat_max_len in a few different ways. reference The mysql documentation...

How do you remove all the options of a select box and then add one option and select it with jQuery?

Another way:

$('#select').empty().append($('<option>').text('---------').attr('value',''));

Under this link, there are good practices https://api.jquery.com/select/

How to dynamically allocate memory space for a string and get that string from user?

realloc is a pretty expensive action... here's my way of receiving a string, the realloc ratio is not 1:1 :

char* getAString()
{    
    //define two indexes, one for logical size, other for physical
    int logSize = 0, phySize = 1;  
    char *res, c;

    res = (char *)malloc(sizeof(char));

    //get a char from user, first time outside the loop
    c = getchar();

    //define the condition to stop receiving data
    while(c != '\n')
    {
        if(logSize == phySize)
        {
            phySize *= 2;
            res = (char *)realloc(res, sizeof(char) * phySize);
        }
        res[logSize++] = c;
        c = getchar();
    }
    //here we diminish string to actual logical size, plus one for \0
    res = (char *)realloc(res, sizeof(char *) * (logSize + 1));
    res[logSize] = '\0';
    return res;
}

Ternary operator in AngularJS templates

Update: Angular 1.1.5 added a ternary operator, so now we can simply write

<li ng-class="$first ? 'firstRow' : 'nonFirstRow'">

If you are using an earlier version of Angular, your two choices are:

  1. (condition && result_if_true || !condition && result_if_false)
  2. {true: 'result_if_true', false: 'result_if_false'}[condition]

item 2. above creates an object with two properties. The array syntax is used to select either the property with name true or the property with name false, and return the associated value.

E.g.,

<li class="{{{true: 'myClass1 myClass2', false: ''}[$first]}}">...</li>
 or
<li ng-class="{true: 'myClass1 myClass2', false: ''}[$first]">...</li>

$first is set to true inside an ng-repeat for the first element, so the above would apply class 'myClass1' and 'myClass2' only the first time through the loop.

With ng-class there is an easier way though: ng-class takes an expression that must evaluate to one of the following:

  1. a string of space-delimited class names
  2. an array of class names
  3. a map/object of class names to boolean values.

An example of 1) was given above. Here is an example of 3, which I think reads much better:

 <li ng-class="{myClass: $first, anotherClass: $index == 2}">...</li>

The first time through an ng-repeat loop, class myClass is added. The 3rd time through ($index starts at 0), class anotherClass is added.

ng-style takes an expression that must evaluate to a map/object of CSS style names to CSS values. E.g.,

 <li ng-style="{true: {color: 'red'}, false: {}}[$first]">...</li>

How to show a running progress bar while page is loading

Simple Steps, follow them and i guess it will solve your problem

Include these Css in your page,

.progress {
      position: relative;
      height: 2px;
      display: block;
      width: 100%;
      background-color: white;
      border-radius: 2px;
      background-clip: padding-box;
      /*margin: 0.5rem 0 1rem 0;*/
      overflow: hidden;

    }
    .progress .indeterminate {
background-color:black; }
    .progress .indeterminate:before {
      content: '';
      position: absolute;
      background-color: #2C67B1;
      top: 0;
      left: 0;
      bottom: 0;
      will-change: left, right;
      -webkit-animation: indeterminate 2.1s cubic-bezier(0.65, 0.815, 0.735, 0.395) infinite;
              animation: indeterminate 2.1s cubic-bezier(0.65, 0.815, 0.735, 0.395) infinite; }
    .progress .indeterminate:after {
      content: '';
      position: absolute;
      background-color: #2C67B1;
      top: 0;
      left: 0;
      bottom: 0;
      will-change: left, right;
      -webkit-animation: indeterminate-short 2.1s cubic-bezier(0.165, 0.84, 0.44, 1) infinite;
              animation: indeterminate-short 2.1s cubic-bezier(0.165, 0.84, 0.44, 1) infinite;
      -webkit-animation-delay: 1.15s;
              animation-delay: 1.15s; }

    @-webkit-keyframes indeterminate {
      0% {
        left: -35%;
        right: 100%; }
      60% {
        left: 100%;
        right: -90%; }
      100% {
        left: 100%;
        right: -90%; } }
    @keyframes indeterminate {
      0% {
        left: -35%;
        right: 100%; }
      60% {
        left: 100%;
        right: -90%; }
      100% {
        left: 100%;
        right: -90%; } }
    @-webkit-keyframes indeterminate-short {
      0% {
        left: -200%;
        right: 100%; }
      60% {
        left: 107%;
        right: -8%; }
      100% {
        left: 107%;
        right: -8%; } }
    @keyframes indeterminate-short {
      0% {
        left: -200%;
        right: 100%; }
      60% {
        left: 107%;
        right: -8%; }
      100% {
        left: 107%;
        right: -8%; } }

Then include the progress bar your body tag,

<div class="progress" id="PreLoaderBar">
        <div class="indeterminate"></div>
    </div>

then it will start as your page loads, and now what you have to do is just hide this when the page loads,or set the visibility to none, or hidden, using javascript,

document.onreadystatechange = function () {
            if (document.readyState === "complete") {
                console.log(document.readyState);
                document.getElementById("PreLoaderBar").style.display = "none";
            }
        }

Let me Know if you face any problems and also, you can add any type of progress bar you can easily find them, for this example i have used a indeterminate progress bar.

Why is char[] preferred over String for passwords?

Case String:

    String password = "ill stay in StringPool after Death !!!";
    // some long code goes
    // ...Now I want to remove traces of password
    password = null;
    password = "";
    // above attempts wil change value of password
    // but the actual password can be traced from String pool through memory dump, if not garbage collected

Case CHAR ARRAY:

    char[] passArray = {'p','a','s','s','w','o','r','d'};
    // some long code goes
    // ...Now I want to remove traces of password
    for (int i=0; i<passArray.length;i++){
        passArray[i] = 'x';
    }
    // Now you ACTUALLY DESTROYED traces of password form memory

How do I determine the current operating system with Node.js

var isWin64 = process.env.hasOwnProperty('ProgramFiles(x86)');

Is Unit Testing worth the effort?

Just today, I had to change a class for which a unit test has been written previously.
The test itself was well written and included test scenarios that I hadn't even thought about.
Luckily all of the tests passed, and my change was quickly verified and put into the test environment with confidence.

Why can't I change my input value in React even with the onChange listener

In React, the component will re-render (or update) only if the state or the prop changes.

In your case you have to update the state immediately after the change so that the component will re-render with the updates state value.

onTodoChange(event) {
        // update the state
    this.setState({name: event.target.value});
}

Difference between getContext() , getApplicationContext() , getBaseContext() and "this"

The question "what the Context is" is one of the most difficult questions in the Android universe.

Context defines methods that access system resources, retrieve application's static assets, check permissions, perform UI manipulations and many more. In essence, Context is an example of God Object anti-pattern in production.

When it comes to which kind of Context should we use, it becomes very complicated because except for being God Object, the hierarchy tree of Context subclasses violates Liskov Substitution Principle brutally.

This blog post (now from Wayback Machine) attempts to summarize Context classes applicability in different situations.

Let me copy the main table from that post for completeness:

+----------------------------+-------------+----------+---------+-----------------+-------------------+
|                            | Application | Activity | Service | ContentProvider | BroadcastReceiver |
+----------------------------+-------------+----------+---------+-----------------+-------------------+
| Show a Dialog              | NO          | YES      | NO      | NO              | NO                |
| Start an Activity          | NO¹         | YES      | NO¹     | NO¹             | NO¹               |
| Layout Inflation           | NO²         | YES      | NO²     | NO²             | NO²               |
| Start a Service            | YES         | YES      | YES     | YES             | YES               |
| Bind to a Service          | YES         | YES      | YES     | YES             | NO                |
| Send a Broadcast           | YES         | YES      | YES     | YES             | YES               |
| Register BroadcastReceiver | YES         | YES      | YES     | YES             | NO³               |
| Load Resource Values       | YES         | YES      | YES     | YES             | YES               |
+----------------------------+-------------+----------+---------+-----------------+-------------------+
  1. An application CAN start an Activity from here, but it requires that a new task be created. This may fit specific use cases, but can create non-standard back stack behaviors in your application and is generally not recommended or considered good practice.
  2. This is legal, but inflation will be done with the default theme for the system on which you are running, not what’s defined in your application.
  3. Allowed if the receiver is null, which is used for obtaining the current value of a sticky broadcast, on Android 4.2 and above.

screenshot

Adding an onclick event to a div element

maybe your script tab has some problem.

if you set type, must type="application/javascript".

<!DOCTYPE html>
<html>
    <head>
        <title>
            Hello
        </title>
    </head>
    <body>
        <div onclick="showMsg('Hello')">
            Click me show message
        </div>
        <script type="application/javascript">
            function showMsg(item) {
            alert(item);
        }
        </script>
    </body>
</html>

Git says remote ref does not exist when I delete remote branch

Given that the remote branch is remotes/origin/test you can use two ways:

git push origin --delete test

and

git branch -D -r origin/test

How to enable support of CPU virtualization on Macbook Pro?

Here is a way to check is virtualization is enabled or disabled by the firmware as suggested by this link in parallels.com.

How to check that Intel VT-x is supported in CPU:

  1. Open Terminal application from Application/Utilities

  2. Copy/paste command bellow

sysctl -a | grep machdep.cpu.features

  1. You may see output similar to:

Mac:~ user$ sysctl -a | grep machdep.cpu.features kern.exec: unknown type returned machdep.cpu.features: FPU VME DE PSE TSC MSR PAE MCE CX8 APIC SEP MTRR PGE MCA CMOV PAT CLFSH DS ACPI MMX FXSR SSE SSE2 SS HTT TM SSE3 MON VMX EST TM2 TPR PDCM

If you see VMX entry then CPU supports Intel VT-x feature, but it still may be disabled.

Refer to this link on Apple.com to enable hardware support for virtualization:

Creating PHP class instance with a string

have a look at example 3 from http://www.php.net/manual/en/language.oop5.basic.php

$className = 'Foo';
$instance = new $className(); // Foo()

postgres default timezone

Maybe not related to the question, but I needed to use CST, set the system timezone to the desired tz (America/...) and then in postgresql conf set the value of the timezone to 'localtime' and it worked as a charm, current_time printing the right time (Postgresql 9.5 on Ubuntu 16)

MySQL Error: : 'Access denied for user 'root'@'localhost'

Although a old one, I was getting the same error while setting up the mysql-8 zip version. Finally, switched to installer version which worked seamlessly. During installation, there is a prompt to setup the root password. Once set, it works for sure.

enter image description here

Proper use of 'yield return'

The usage of yield is similar to the keyword return, except that it will return a generator. And the generator object will only traverse once.

yield has two benefits:

  1. You do not need to read these values twice;
  2. You can get many child nodes but do not have to put them all in memory.

There is another clear explanation maybe help you.

Automatically create requirements.txt

Make sure to run pip3 for python3.7.

pip3 freeze >> yourfile.txt

Before executing the above command make sure you have created a virtual environment.

python3:

pip3 install virtualenv
python3 -m venv <myenvname> 

python2:

pip install virtualenv
virtualenv <myenvname>

After that put your source code in the directory. If you run the python file now, probably it won't launch if you are using non-native modules. You can install those modules by running pip3 install <module> or pip install <module>.

This will not affect you entire module list except the environment you are in.

Now you can execute the command at the top and now you have a requirements file which contains only the modules you installed in the virtual environment. Now you can run the command at the top.

I advise everyone to use environments as it makes things easier when it comes to stuff like this.

PostgreSQL next value of the sequences?

I tried this and it works perfectly

@Entity
public class Shipwreck {
  @Id
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "seq")
  @Basic(optional = false)
  @SequenceGenerator(name = "seq", sequenceName = "shipwreck_seq", allocationSize = 1)
  Long id;

....

CREATE SEQUENCE public.shipwreck_seq
    INCREMENT 1
    START 110
    MINVALUE 1
    MAXVALUE 9223372036854775807
    CACHE 1;

How do I debug Node.js applications?

Start your node process with --inspect flag.

node --inspect index.js

and then Open chrome://inspect in chrome. Click the "Open dedicated DevTools for Node" link or install this chrome extension for easily opening chrome DevTools.

For more info refer to this link

Pointer vs. Reference

My rule of thumb is:

Use pointers if you want to do pointer arithmetic with them (e.g. incrementing the pointer address to step through an array) or if you ever have to pass a NULL-pointer.

Use references otherwise.

package javax.mail and javax.mail.internet do not exist

For anyone still looking to use the aforementioned IMAP library but need to use gradle, simply add this line to your modules gradle file (not the main gradle file)

compile group: 'javax.mail', name: 'mail', version: '1.4.1'

The links to download the .jar file were dead for me, so had to go with an alternate route.

Hope this helps :)

Errno 10060] A connection attempt failed because the connected party did not properly respond after a period of time

As ping works, but telnetto port 80 does not, the HTTP port 80 is closed on your machine. I assume that your browser's HTTP connection goes through a proxy (as browsing works, how else would you read stackoverflow?). You need to add some code to your python program, that handles the proxy, like described here:

Using an HTTP PROXY - Python

Google Maps JavaScript API RefererNotAllowedMapError

There are lots of supposed solutions accross several years, and some don’t work any longer and some never did, thus my up-to-date take working per end of July 2018.

Setup:

Google Maps JavaScript API has to work properly with…

  • multiple domains calling the API: example.com and example.net
  • arbitrary subdomains: user22656.example.com, etc.
  • both secure and standard HTTP protocols: http://www.example.com/ and https://example.net/
  • indefinite path structure (i.e. a large number of different URL paths)

Solution:

  • Actually using the pattern from the placeholder: <https (or) http>://*.example.com/*.
  • Not omitting the protocol, but adding two entries per domain (one per protocol).
  • An additional entry for subdomains (with a *. leading the hostname).
  • I had the feeling that the RefererNotAllowedMapError error still appeared using the proper configuration (and having waited ample time). I deleted the credential key, repeated the request (now getting InvalidKeyMapError), created new credentials (using the exact same setup), and it worked ever since.
  • Adding mere protocol and domain seemed not to have included subdomains.
  • For one of the domains, the working configuration looks like this:

Screenshot from Google API configuration

(As text:)

Accept requests from these HTTP referrers (web sites)
    https://*.example.com/*
    https://example.com/*
    http://*.example.com/*
    http://example.com/*

how to print json data in console.log

{"success":true,"input_data":{"quantity-row_122":"1","price-row_122":" 35.1 "}}

console.dir() will do what you need. It will give you a hierarchical structure of the data.

success:function(data){
     console.dir(data);
}

like so

> Object
  > input_data: Object
      price-row_122: " 35.1 "
      quantity-row_122: "1"
    success: true

I don't think you need console.log(JSON.stringify(data)).

To get the data you can do this without stringify:

console.log(data.success); // true
console.log(data.input_data['quantity-row_122']) // "1"
console.log(data.input_data['price-row_122']) // " 35.1 "

Note

The value from input_data Object will be typeof "1": String, but you can convert to number(Int or Float) using ParseInt or ParseFloat, like so:

 typeof parseFloat(data.input_data['price-row_122'], 10) // "number"
 parseFloat(data.input_data['price-row_122'], 10) // 35.1

How do I declare an array with a custom class?

To default-initialize an array of Ts, T must be default constructible. Normally the compiler gives you a default constructor for free. However, since you declared a constructor yourself, the compiler does not generate a default constructor.

Your options:

  • add a default constructor to name, if that makes sense (I don't think so, but I don't know the problem domain);
  • initialize all the elements of the array upon declaration (you can do this because name is an aggregate);

      name someName[4] = { { "Arthur", "Dent" },
                           { "Ford", "Prefect" },
                           { "Tricia", "McMillan" },
                           { "Zaphod", "Beeblebrox" }
                         };
    
  • use a std::vector instead, and only add element when you have them constructed.

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

The point for diamond operator is simply to reduce typing of code when declaring generic types. It doesn't have any effect on runtime whatsoever.

The only difference if you specify in Java 5 and 6,

List<String> list = new ArrayList();

is that you have to specify @SuppressWarnings("unchecked") to the list (otherwise you will get an unchecked cast warning). My understanding is that diamond operator is trying to make development easier. It's got nothing to do on runtime execution of generics at all.

When should I write the keyword 'inline' for a function/method?

C++ inline is totally different to C inline.

#include <iostream>
extern inline int i[];
int i [5];
struct c {
  int function (){return 1;} //implicitly inline
  static inline int j = 3; //explicitly inline
};
int main() {
  c j;
  std::cout << i;
}

inline on its own affects the compiler, assembler and the linker. It is a directive to the compiler saying only emit a symbol for this function/data if it's used in the translation unit, and if it is, then like class methods, tell the assembler to store them in the section .section .text.c::function(),"axG",@progbits,c::function(),comdat or .section .bss.i,"awG",@nobits,i,comdat for data. Template instantiations also go in their own comdat groups.

This follows .section name, "flags"MG, @type, entsize, GroupName[, linkage]. For instance, the section name is .text.c::function(). axG means the section is allocatable, executable and in a group i.e. a group name will be specified (and there is no M flag so no entsize will be specified); @progbits means the section contains data and isn't blank; c::function() is the group name and the group has comdat linkage meaning that in all object files, all sections encountered with this group name tagged with comdat will be removed from the final executable except for 1 i.e. the compiler makes sure that there is only one definition in the translation unit and then tells the assembler to put it in its own group in the object file (1 section in 1 group) and then the linker will make sure that if any object files have a group with the same name, then only include one in the final .exe. The difference between inline and not using inline is now visible to the assembler and as a result the linker, because it's not stored in the regular .data or .text etc by the assembler due to their directives.

static inline in a class means this it a type definition and not declaration (allows static member to be defined in the class) and make it inline; it now behaves as above.

static inline at file scope only affects the compiler. It means to the compiler: only emit a symbol for this function/data if it's used in the translation unit and do so as a regular static symbol (store in.text /.data without .globl directive). To the assembler there is now no difference between static and static inline

extern inline is a declaration that means you must define this symbol in the translation unit or throw compiler error; if it's defined then treat it as a regular inline and to the assembler and linker there will be no difference between extern inline and inline, so this is a compiler guard only.

extern inline int i[];
extern int i[]; //allowed repetition of declaration with incomplete type, inherits inline property
extern int i[5]; //declaration now has complete type
extern int i[5]; //allowed redeclaration if it is the same complete type or has not yet been completed
extern int i[6]; //error, redeclaration with different complete type
int i[5]; //definition, must have complete type and same complete type as the declaration if there is a declaration with a complete type

The whole of the above without the error line collapses to inline int i[5]. Obviously if you did extern inline int i[] = {5}; then extern would be ignored due to the explicit definition through assignment.

inline on a namespace, see this and this

Best way to get the max value in a Spark dataframe column

I believe the best solution will be using head()

Considering your example:

+---+---+
|  A|  B|
+---+---+
|1.0|4.0|
|2.0|5.0|
|3.0|6.0|
+---+---+

Using agg and max method of python we can get the value as following :

from pyspark.sql.functions import max df.agg(max(df.A)).head()[0]

This will return: 3.0

Make sure you have the correct import:
from pyspark.sql.functions import max The max function we use here is the pySPark sql library function, not the default max function of python.

How to remove last n characters from every element in the R vector

The same may be achieved with the stringi package:

library('stringi')
char_array <- c("foo_bar","bar_foo","apple","beer")
a <- data.frame("data"=char_array, "data2"=1:4)
(a$data <- stri_sub(a$data, 1, -4)) # from the first to the last but 4th char
## [1] "foo_" "bar_" "ap"   "b" 

Best way to do a PHP switch with multiple values per case?

maybe

        switch ($variable) {
        case 0:
            exit;
            break;
        case (1 || 3 || 4 || 5 || 6):
            die(var_dump('expression'));
        default:
            die(var_dump('default'));
            # code...
            break;
    }

find filenames NOT ending in specific extensions on Unix?

$ find . -name \*.exe -o -name \*.dll -o -print

The first two -name options have no -print option, so they skipped. Everything else is printed.

How to fetch JSON file in Angular 2

I needed to load the settings file synchronously, and this was my solution:

export function InitConfig(config: AppConfig) { return () => config.load(); }

import { Injectable } from '@angular/core';

@Injectable()
export class AppConfig {
    Settings: ISettings;

    constructor() { }

    load() {
        return new Promise((resolve) => {
            this.Settings = this.httpGet('assets/clientsettings.json');
            resolve(true);
        });
    }

    httpGet(theUrl): ISettings {
        const xmlHttp = new XMLHttpRequest();
        xmlHttp.open( 'GET', theUrl, false ); // false for synchronous request
        xmlHttp.send( null );
        return JSON.parse(xmlHttp.responseText);
    }
}

This is then provided as a app_initializer which is loaded before the rest of the application.

app.module.ts

{
      provide: APP_INITIALIZER,
      useFactory: InitConfig,
      deps: [AppConfig],
      multi: true
    },

My httpd.conf is empty

The /etc/apache2/httpd.conf is empty in Ubuntu, because the Apache configuration resides in /etc/apache2/apache2.conf!

“httpd.conf is for user options.” No it isn't, it's there for historic reasons.

Using Apache server, all user options should go into a new *.conf-file inside /etc/apache2/conf.d/. This method should be "update-safe", as httpd.conf or apache2.conf may get overwritten on the next server update.

Inside /etc/apache2/apache2.conf, you will find the following line, which includes those files:

# Include generic snippets of statements
Include conf.d/

As of Apache 2.4+ the user configuration directory is /etc/apache2/conf-available/. Use a2enconf FILENAME_WITHOUT_SUFFIX to enable the new configuration file or manually create a symlink in /etc/apache2/conf-enabled/. Be aware that as of Apache 2.4 the configuration files must have the suffix .conf (e.g. conf-available/my-settings.conf);

Visual Studio Code always asking for git credentials

In general, you can use the built-in credential storage facilities:

git config --global credential.helper store

Or, if you're on Windows, you can use their credential system:

git config --global credential.helper wincred

Or, if you're on MacOS, you can use their credential system:

git config --global credential.helper osxkeychain

The first solution is optimal in most situations.

How to check the value given is a positive or negative integer?

To check a number is positive, negative or negative zero. Check its sign using Math.sign() method it will provide you -1,-0,0 and 1 on the basis of positive negative and negative zero or zero numbers

 Math.sign(-3) // -1
 Math.sign(3) // 1
 Math.sign(-0) // -0
 Math.sign(0) // 0

Directory.GetFiles: how to get only filename, not full path?

Use this to obtain only the filename.

Path.GetFileName(files[0]);

How to get name of calling function/method in PHP?

I needed something to just list the calling classes/methods (working on a Magento project).

While debug_backtrace provides tons of useful information, the amount of information it spewed out for the Magento installation was overwhelming (over 82,000 lines!) Since I was only concerned with the calling function and class, I worked this little solution up:

$callers = debug_backtrace();
foreach( $callers as $call ) {
    echo "<br>" . $call['class'] . '->' . $call['function'];
}

Django Rest Framework File Upload

You can generalize @Nithin's answer to work directly with DRF's existing serializer system by generating a parser class to parse specific fields which are then fed directly into the standard DRF serializers:

from django.http import QueryDict
import json
from rest_framework import parsers


def gen_MultipartJsonParser(json_fields):
    class MultipartJsonParser(parsers.MultiPartParser):

        def parse(self, stream, media_type=None, parser_context=None):
            result = super().parse(
                stream,
                media_type=media_type,
                parser_context=parser_context
            )
            data = {}
            # find the data field and parse it
            qdict = QueryDict('', mutable=True)
            for json_field in json_fields:
                json_data = result.data.get(json_field, None)
                if not json_data:
                    continue
                data = json.loads(json_data)
                if type(data) == list:
                    for d in data:
                        qdict.update({json_field: d})
                else:
                    qdict.update({json_field: data})

            return parsers.DataAndFiles(qdict, result.files)

    return MultipartJsonParser

This is used like:

class MyFileViewSet(ModelViewSet):
    parser_classes = [gen_MultipartJsonParser(['tags', 'permissions'])]
    #                                           ^^^^^^^^^^^^^^^^^^^
    #                              Fields that need to be further JSON parsed
    ....

How to find pg_config path

You can find the pg_config directory using its namesake:

$ pg_config --bindir
/usr/lib/postgresql/9.1/bin
$ 

Tested on Mac and Debian. The only wrinkle is that I can't see how to find the bindir for different versions of postgres installed on the same machine. It's fairly easy to guess though! :-)

Note: I updated my pg_config to 9.5 on Debian with:

sudo apt-get install postgresql-server-dev-9.5

Converting HTML to PDF using PHP?

If you wish to create a pdf from php, pdflib will help you (as some others suggested).

Else, if you want to convert an HTML page to PDF via PHP, you'll find a little trouble outta here.. For 3 years I've been trying to do it as best as I can.

So, the options I know are:

DOMPDF : php class that wraps the html and builds the pdf. Works good, customizable (if you know php), based on pdflib, if I remember right it takes even some CSS. Bad news: slow when the html is big or complex.

HTML2PS: same as DOMPDF, but this one converts first to a .ps (ghostscript) file, then, to whatever format you need (pdf, jpg, png). For me is little better than dompdf, but has the same speed problem.. but, better compatibility with CSS.

Those two are php classes, but if you can install some software on the server, and access it throught passthru() or system(), give a look to these too:

wkhtmltopdf: based on webkit (safari's wrapper), is really fast and powerful.. seems like this is the best one (atm) for converting html pages to pdf on the fly; taking only 2 seconds for a 3 page xHTML document with CSS2. It is a recent project, anyway, the google.code page is often updated.

htmldoc : This one is a tank, it never really stops/crashes.. the project looks dead since 2007, but anyway if you don't need CSS compatibility this can be nice for you.

How to change default text file encoding in Eclipse?

Nanda's answer wasn't enough in my setup. What I needed to do is:

  • Window > Preferences > General > Content Types
  • Select Text > HTML in the tree
  • Select all file associations, particularly .html
  • Input "UTF-8" in the text-field "default encoding"

Import / Export database with SQL Server Server Management Studio

Another solutions is - Backing Up and Restoring Database

Back Up the System Database

To back up the system database using Microsoft SQL Server Management Studio Express, follow the steps below:

  1. Download and install Microsoft SQL Server 2008 Management Studio Express from the Microsoft web site: http://www.microsoft.com/en-us/download/details.aspx?id=7593

  2. After Microsoft SQL Server Management Studio Express has been installed, launch the application to connect to the system database. The "Connect to Server" dialog box displays. In the "Server name:" field, enter the name of the Webtrends server on which the system database is installed. In the "Authentication:" field select "Windows Authentication" if logged into the Windows machine using the Webtrends service account or an account with rights to make changes to the system database. Otherwise, select "SQL Server Authentication" from the drop-down menu and enter the credentials for a SQL Server account which has the needed rights. Click "Connect" to connect to the database.

  3. Expand "Databases", right-click on "wt_sched" and select "Tasks" > "Back Up..." from the context menu. The "Back Up Database" dialog box displays. Under the "Source" section, ensure the "wt_sched" is selected for the "Database:" and "Backup type:" is "Full." Under "Backup set" provide a name, description and expiration date as needed and then select "Add..." under the "Destination" section and designate the file name and path where the backup will be saved. It may be necessary to select the "Overwrite all existing backup sets" option in the Options section if a backup already exists and is to be overwritten.
  4. Select "OK" to complete the backup process.

  5. Repeat the above steps for the "wtMaster" part of the database.

Restore the System Database

To restore the system database using Microsoft SQL Server Management Studio, follow the steps below:

  1. If you haven't already, download and install Microsoft SQL Server 2008 Management Studio Express from the Microsoft web site: http://www.microsoft.com/en-us/download/details.aspx?id=7593

  2. After Microsoft SQL Server Management Studio has been installed, launch the application to connect to the system database. The "Connect to Server" dialog box displays. In the "Server type:" field, select "Database Engine" (default). In the "Server name:" field, select "\WTSYSTEMDB" where is the name of the Webtrends server where the database is located. WTSYSTEMDB is the name of the database instance in a default installation. In the "Authentication:" field select "Windows Authentication" if logged into the Windows machine using the Webtrends service account or an account with rights to make changes to the system database. Otherwise, select "SQL Server Authentication" from the drop-down menu and enter the credentials for a SQL Server account which has the needed rights. Click "Connect" to connect to the database.

  3. Expand "Databases", right-click on "wt_sched" and select "Delete" from the context menu. Make sure "Delete backup and restore history information for databases" check-box is checked.

  4. Select "OK" to complete the deletion process.

  5. Repeat the above steps for the "wtMaster" part of the database.

  6. Right click on "Databases" and select "Restore Database..." from the context menu. In the "To database:" field type in "wt_sched". Select the "From device:" radio button. Click on the ellipse (...) to the right of the "From device:" text field. Click the "Add" button. Navigate to and select the backup file for "wt_sched". Select "OK" on the "Locate Backup File" form. Select "OK" on the "Specify Backup" form. Check the check-box in the restore column next to "wt_sched-Full Database Backup". Select "OK" on the "Restore Database" form.

  7. Repeat step 6 for the "wtMaster" part of the database.

Courtesy - http://kb.webtrends.com/articles/How_To/Backing-Up-and-Restoring-the-System-Database-using-MS-SQL-Management-Studio

How to exit in Node.js

As @Dominic pointed out, throwing an uncaught error is better practice instead of calling process.exit([code]):
process.exitCode = 1; throw new Error("my module xx condition failed");

Increase max execution time for php

PHP file (for example, my_lengthy_script.php)

ini_set('max_execution_time', 300); //300 seconds = 5 minutes

.htaccess file

<IfModule mod_php5.c>
php_value max_execution_time 300
</IfModule>

More configuration options

<IfModule mod_php5.c>
php_value post_max_size 5M
php_value upload_max_filesize 5M
php_value memory_limit 128M
php_value max_execution_time 300
php_value max_input_time 300
php_value session.gc_maxlifetime 1200
</IfModule>

If wordpress, set this in the config.php file,

define('WP_MEMORY_LIMIT', '128M');

If drupal, sites/default/settings.php

ini_set('memory_limit', '128M');

If you are using other frameworks,

ini_set('memory_limit', '128M');

You can increase memory as gigabyte.

ini_set('memory_limit', '3G'); // 3 Gigabytes

259200 means:-

( 259200/(60x60 minutes) ) / 24 hours ===> 3 Days

More details on my blog

What does file:///android_asset/www/index.html mean?

The URI "file:///android_asset/" points to YourProject/app/src/main/assets/.

Note: android_asset/ uses the singular (asset) and src/main/assets uses the plural (assets).

Suppose you have a file YourProject/app/src/main/assets/web_thing.html that you would like to display in a WebView. You can refer to it like this:

WebView webViewer = (WebView) findViewById(R.id.webViewer);
webView.loadUrl("file:///android_asset/web_thing.html");

The snippet above could be located in your Activity class, possibly in the onCreate method.

Here is a guide to the overall directory structure of an android project, that helped me figure out this answer.

What do "branch", "tag" and "trunk" mean in Subversion repositories?

Now that's the thing about software development, there's no consistent knowledge about anything, everybody seems to have it their own way, but that's because it is a relatively young discipline anyway.

Here's my plain simple way,

trunk - The trunk directory contains the most current, approved, and merged body of work. Contrary to what many have confessed, my trunk is only for clean, neat, approved work, and not a development area, but rather a release area.

At some given point in time when the trunk seems all ready to release, then it is tagged and released.

branches - The branches directory contains experiments and ongoing work. Work under a branch stays there until is approved to be merged into the trunk. For me, this is the area where all the work is done.

For example: I can have an iteration-5 branch for a fifth round of development on the product, maybe a prototype-9 branch for a ninth round of experimenting, and so on.

tags - The tags directory contains snapshots of approved branches and trunk releases. Whenever a branch is approved to merge into the trunk, or a release is made of the trunk, a snapshot of the approved branch or trunk release is made under tags.

I suppose with tags I can jump back and forth through time to points interest quite easily.

How to blur background images in Android

You can have a view with Background color as black and set alpha for the view as 0.7 or whatever as per your requirement.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/onboardingimg1">
    <View
        android:id="@+id/opacityFilter"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@android:color/black"
        android:layout_alignParentBottom="true"
        android:alpha="0.7">
    </View>


</RelativeLayout>

How is Pythons glob.glob ordered?

Please try this code:

sorted(glob.glob( os.path.join(path, '*.png') ),key=lambda x:float(re.findall("([0-9]+?)\.png",x)[0]))

How to return a html page from a restful controller in spring boot?

I'm not using Thymeleaf and the only way it worked for me was with @Controller in the class and

@RequestMapping(method = RequestMethod.GET, value = "/")
public String index() {
    return "index.html";
}

No authenticationScheme was specified, and there was no DefaultChallengeScheme found with default authentification and custom authorization

Many answer above are correct but same time convoluted with other aspects of authN/authZ. What actually resolves the exception in question is this line:

services.AddScheme<YourAuthenticationOptions, YourAuthenticationHandler>(YourAuthenticationSchemeName, options =>
    {
        options.YourProperty = yourValue;
    })

How to remove a row from JTable?

A JTable normally forms the View part of an MVC implementation. You'll want to remove rows from your model. The JTable, which should be listening for these changes, will update to reflect this removal. Hence you won't find removeRow() or similar as a method on JTable.

Java - Relative path of a file in a java web application

You may be able to simply access a pre-arranged file path on the system. This is preferable since files added to the webapp directory might be lost or the webapp may not be unpacked depending on system configuration.

In our server, we define a system property set in the App Server's JVM which points to the "home directory" for our app's external data. Of course this requires modification of the App Server's configuration (-DAPP_HOME=... added to JVM_OPTS at startup), we do it mainly to ease testing of code run outside the context of an App Server.

You could just as easily retrieve a path from the servlet config:

<web-app>
<context-param>
    <param-name>MyAppHome</param-name>
    <param-value>/usr/share/myapp</param-value>
</context-param>
...
</web-app>

Then retrieve this path and use it as the base path to read the file supplied by the client.

public class MyAppConfig implements ServletContextListener {

    // NOTE: static references are not a great idea, shown here for simplicity
    static File appHome;
    static File customerDataFile;

    public void contextInitialized(ServletContextEvent e) {

        appHome = new File(e.getServletContext().getInitParameter("MyAppHome"));
        File customerDataFile = new File(appHome, "SuppliedFile.csv");
    }
}

class DataProcessor {
    public void processData() {
        File dataFile = MyAppConfig.customerDataFile;
        // ...
    }
}

As I mentioned the most likely problem you'll encounter is security restrictions. Nothing guarantees webapps can ready any files above their webapp root. But there are generally simple methods for granting exceptions for specific paths to specific webapps.

Regardless of the code in which you then need to access this file, since you are running within a web application you are guaranteed this is initialized first, and can stash it's value somewhere convenient for the rest of your code to refer to, as in my example or better yet, just simply pass the path as a paramete to the code which needs it.

How can I programmatically determine if my app is running in the iphone simulator?

My answer is based on @Daniel Magnusson answer and comments of @Nuthatch and @n.Drake. and I write it to save some time for swift users working on iOS9 and onwards.

This is what worked for me:

if UIDevice.currentDevice().name.hasSuffix("Simulator"){
    //Code executing on Simulator
} else{
    //Code executing on Device
}

Custom HTTP headers : naming conventions

RFC6648 recommends that you assume that your custom header "might become standardized, public, commonly deployed, or usable across multiple implementations." Therefore, it recommends not to prefix it with "X-" or similar constructs.

However, there is an exception "when it is extremely unlikely that [your header] will ever be standardized." For such "implementation-specific and private-use" headers, the RFC says a namespace such as a vendor prefix is justified.

How can I use the apply() function for a single column?

Let me try a complex computation using datetime and considering nulls or empty spaces. I am reducing 30 years on a datetime column and using apply method as well as lambda and converting datetime format. Line if x != '' else x will take care of all empty spaces or nulls accordingly.

df['Date'] = df['Date'].fillna('')
df['Date'] = df['Date'].apply(lambda x : ((datetime.datetime.strptime(str(x), '%m/%d/%Y') - datetime.timedelta(days=30*365)).strftime('%Y%m%d')) if x != '' else x)

SQL Server: Error converting data type nvarchar to numeric

I was running into this error while converting from nvarchar to float.
What I had to do was to use the LEFT function on the nvarchar field.

Example: Left(Field,4)

Basically, the query will look like:

Select convert(float,left(Field,4)) from TABLE

Just ridiculous that SQL would complicate it to this extent, while with C# it's a breeze!
Hope it helps someone out there.

Creating a DateTime in a specific Time Zone in c#

You'll have to create a custom object for that. Your custom object will contain two values:

Not sure if there already is a CLR-provided data type that has that, but at least the TimeZone component is already available.

What is console.log?

console.log has nothing to do with jQuery. It is a common object/method provided by debuggers (including the Chrome debugger and Firebug) that allows a script to log data (or objects in most cases) to the JavaScript console.

Unused arguments in R

Change the definition of multiply to take additional unknown arguments:

multiply <- function(a, b, ...) {
  # Original code
}

Use .htaccess to redirect HTTP to HTTPs

None if this worked for me. First of all I had to look at my provider to see how they activate SSL in .htaccess my provider gives

<IfModule mod_rewrite.c>
   RewriteEngine On
   RewriteCond %{HTTP:HTTPS} !on
   RewriteRule (.*) https://%{SERVER_NAME}/$1 [QSA,L,R=301]
</IfModule>

But what took me days of research is I had to add to wp-config.php the following lines as my provided site is behind a proxy :

/**
 * Force le SSL
 */
define('FORCE_SSL_ADMIN', true);
if (strpos($_SERVER['HTTP_X_FORWARDED_PROTO'], 'https') !== false) $_SERVER['HTTPS']='on';

How do you add an SDK to Android Studio?

For those starting with an existing IDEA installation (IDEA 15 in my case) to which they're adding the Android SDK (and not starting formally speaking with Android Studio), ...

Download (just) the SDK to your filesystem (somewhere convenient to you; it doesn't matter where).

When creating your first project and you get to the Project SDK: bit (or adding the Android SDK ahead of time as you wish), navigate (New) to the root of what you exploded into the filesystem as suggested by some of the other answers here.

At that point you'll get a tiny dialog to confirm with:

Java SDK:     1.7            (e.g.)
Build target: Android 6.0    (e.g.)

You can click OK whereupon you'll see what you did as an option in the Project SDK: drop-down, e.g.:

Android API 23 Platform (java version "1.7.0_67")

php resize image on upload

You can use Imagine library also. It uses GD and Imagick.

Default settings Raspberry Pi /etc/network/interfaces

These are the default settings I have for /etc/network/interfaces (including WiFi settings) for my Raspberry Pi 1:

auto lo

iface lo inet loopback
iface eth0 inet dhcp

allow-hotplug wlan0
iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp

How to use Fiddler to monitor WCF service

Standard WCF Tracing/Diagnostics

If for some reason you are unable to get Fiddler to work, or would rather log the requests another way, another option is to use the standard WCF tracing functionality. This will produce a file that has a nice viewer.

Docs

See https://docs.microsoft.com/en-us/dotnet/framework/wcf/samples/tracing-and-message-logging

Configuration

Add the following to your config, make sure c:\logs exists, rebuild, and make requests:

  <system.serviceModel>
    <diagnostics>
      <!-- Enable Message Logging here. -->
      <!-- log all messages received or sent at the transport or service model levels -->
      <messageLogging logEntireMessage="true"
                      maxMessagesToLog="300"
                      logMessagesAtServiceLevel="true"
                      logMalformedMessages="true"
                      logMessagesAtTransportLevel="true" />
    </diagnostics>
  </system.serviceModel>

  <system.diagnostics>
    <sources>
      <source name="System.ServiceModel" switchValue="Information,ActivityTracing"
        propagateActivity="true">
        <listeners>
          <add name="xml" />
        </listeners>
      </source>
      <source name="System.ServiceModel.MessageLogging">
        <listeners>
          <add name="xml" />
        </listeners>
      </source>
    </sources>
    <sharedListeners>
      <add initializeData="C:\logs\TracingAndLogging-client.svclog" type="System.Diagnostics.XmlWriterTraceListener"
        name="xml" />
    </sharedListeners>
    <trace autoflush="true" />
  </system.diagnostics>

What is /var/www/html?

In the most shared hosts you can't set it.

On a VPS or dedicated server, you can set it, but everything has its price.

On shared hosts, in general you receive a Linux account, something such as /home/(your username)/, and the equivalent of /var/www/html turns to /home/(your username)/public_html/ (or something similar, such as /home/(your username)/www)

If you're accessing your account via FTP, you automatically has accessing the your */home/(your username)/ folder, just find the www or public_html and put your site in it.

If you're using absolute path in the code, bad news, you need to refactor it to use relative paths in the code, at least in a shared host.

Ansible: how to get output to display

Every Ansible task when run can save its results into a variable. To do this, you have to specify which variable to save the results into. Do this with the register parameter, independently of the module used.

Once you save the results to a variable you can use it later in any of the subsequent tasks. So for example if you want to get the standard output of a specific task you can write the following:

---
- hosts: localhost
  tasks:
    - shell: ls
      register: shell_result

    - debug:
        var: shell_result.stdout_lines

Here register tells ansible to save the response of the module into the shell_result variable, and then we use the debug module to print the variable out.

An example run would look like the this:

PLAY [localhost] ***************************************************************

TASK [command] *****************************************************************
changed: [localhost]

TASK [debug] *******************************************************************
ok: [localhost] => {
    "shell_result.stdout_lines": [
        "play.yml"
    ]
}

Responses can contain multiple fields. stdout_lines is one of the default fields you can expect from a module's response.

Not all fields are available from all modules, for example for a module which doesn't return anything to the standard out you wouldn't expect anything in the stdout or stdout_lines values, however the msg field might be filled in this case. Also there are some modules where you might find something in a non-standard variable, for these you can try to consult the module's documentation for these non-standard return values.

Alternatively you can increase the verbosity level of ansible-playbook. You can choose between different verbosity levels: -v, -vvv and -vvvv. For example when running the playbook with verbosity (-vvv) you get this:

PLAY [localhost] ***************************************************************

TASK [command] *****************************************************************
(...)
changed: [localhost] => {
    "changed": true,
    "cmd": "ls",
    "delta": "0:00:00.007621",
    "end": "2017-02-17 23:04:41.912570",
    "invocation": {
        "module_args": {
            "_raw_params": "ls",
            "_uses_shell": true,
            "chdir": null,
            "creates": null,
            "executable": null,
            "removes": null,
            "warn": true
        },
        "module_name": "command"
    },
    "rc": 0,
    "start": "2017-02-17 23:04:41.904949",
    "stderr": "",
    "stdout": "play.retry\nplay.yml",
    "stdout_lines": [
        "play.retry",
        "play.yml"
    ],
    "warnings": []
}

As you can see this will print out the response of each of the modules, and all of the fields available. You can see that the stdout_lines is available, and its contents are what we expect.

To answer your main question about the jenkins_script module, if you check its documentation, you can see that it returns the output in the output field, so you might want to try the following:

tasks:
  - jenkins_script:
      script: (...)
    register: jenkins_result

  - debug:
      var: jenkins_result.output

Java check if boolean is null

The only thing that can be a null is a non-primivite.

A boolean which can only hold TRUE or FALSE is a primitive. The TRUE/FALSE in memory are actually numbers (0 and 1)

0 = FALSE

1 = TRUE

So when you instantiate an object it will be null String str; // will equal null

On the other hand if you instaniate a primitive it will be assigned to 0 default.

boolean isTrue; // will be 0

int i; // will be 0

What steps are needed to stream RTSP from FFmpeg?

Another streaming command I've had good results with is piping the ffmpeg output to vlc to create a stream. If you don't have these installed, you can add them:

sudo apt install vlc ffmpeg

In the example I use an mpeg transport stream (ts) over http, instead of rtsp. I've tried both, but the http ts stream seems to work glitch-free on my playback devices.

I'm using a video capture HDMI>USB device that sets itself up on the video4linux2 driver as input. Piping through vlc must be CPU-friendly, because my old dual-core Pentium CPU is able to do the real-time encoding with no dropped frames. I've also had audio-sync issues with some of the other methods, where this method always has perfect audio-sync.

You will have to adjust the command for your device or file. If you're using a file as input, you won't need all that v4l2 and alsa stuff. Here's the ffmpeg|vlc command:

ffmpeg -thread_queue_size 1024 -f video4linux2 -input_format mjpeg -i /dev/video0 -r 30 -f alsa -ac 1 -thread_queue_size 1024 -i hw:1,0 -acodec aac -vcodec libx264 -preset ultrafast -crf 18 -s hd720 -vf format=yuv420p -profile:v main -threads 0 -f mpegts -|vlc -I dummy - --sout='#std{access=http,mux=ts,dst=:8554}'

For example, lets say your server PC IP is 192.168.0.10, then the stream can be played by this command:

ffplay http://192.168.0.10:8554
#or
vlc http://192.168.0.10:8554

Using MySQL with Entity Framework

Be careful using connector .net, Connector 6.6.5 have a bug, it is not working for inserting tinyint values as identity, for example:

create table person(
    Id tinyint unsigned primary key auto_increment,
    Name varchar(30)
);

if you try to insert an object like this:

Person p;
p = new Person();
p.Name = 'Oware'
context.Person.Add(p);
context.SaveChanges();

You will get a Null Reference Exception:

Referencia a objeto no establecida como instancia de un objeto.:
   en MySql.Data.Entity.ListFragment.WriteSql(StringBuilder sql)
   en MySql.Data.Entity.SelectStatement.WriteSql(StringBuilder sql)
   en MySql.Data.Entity.InsertStatement.WriteSql(StringBuilder sql)
   en MySql.Data.Entity.SqlFragment.ToString()
   en MySql.Data.Entity.InsertGenerator.GenerateSQL(DbCommandTree tree)
   en MySql.Data.MySqlClient.MySqlProviderServices.CreateDbCommandDefinition(DbProviderManifest providerManifest, DbCommandTree commandTree)
   en System.Data.Common.DbProviderServices.CreateCommandDefinition(DbCommandTree commandTree)
   en System.Data.Common.DbProviderServices.CreateCommand(DbCommandTree commandTree)
   en System.Data.Mapping.Update.Internal.UpdateTranslator.CreateCommand(DbModificationCommandTree commandTree)
   en System.Data.Mapping.Update.Internal.DynamicUpdateCommand.CreateCommand(UpdateTranslator translator, Dictionary`2 identifierValues)
   en System.Data.Mapping.Update.Internal.DynamicUpdateCommand.Execute(UpdateTranslator translator, EntityConnection connection, Dictionary`2 identifierValues, List`1 generatedValues)
   en System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter)
   en System.Data.EntityClient.EntityAdapter.Update(IEntityStateManager entityCache)
   en System.Data.Objects.ObjectContext.SaveChanges(SaveOptions options)
   en System.Data.Entity.Internal.InternalContext.SaveChanges()
   en System.Data.Entity.Internal.LazyInternalContext.SaveChanges()
   en System.Data.Entity.DbContext.SaveChanges()

Until now I haven't found a solution, I had to change my tinyint identity to unsigned int identity, this solved the problem but this is not the right solution.

If you use an older version of Connector.net (I used 6.4.4) you won't have this problem.

If someone knows about the solution, please contact me.

Cheers!

Oware

Changing directory in Google colab (breaking out of the python interpreter)

If you want to use the cd or ls functions , you need proper identifiers before the function names ( % and ! respectively) use %cd and !ls to navigate

.

!ls    # to find the directory you're in ,
%cd ./samplefolder  #if you wanna go into a folder (say samplefolder)

or if you wanna go out of the current folder

%cd ../      

and then navigate to the required folder/file accordingly

Binary Data in JSON String. Something better than Base64

The problem with UTF-8 is that it is not the most space efficient encoding. Also, some random binary byte sequences are invalid UTF-8 encoding. So you can't just interpret a random binary byte sequence as some UTF-8 data because it will be invalid UTF-8 encoding. The benefit of this constrain on the UTF-8 encoding is that it makes it robust and possible to locate multi byte chars start and end whatever byte we start looking at.

As a consequence, if encoding a byte value in the range [0..127] would need only one byte in UTF-8 encoding, encoding a byte value in the range [128..255] would require 2 bytes ! Worse than that. In JSON, control chars, " and \ are not allowed to appear in a string. So the binary data would require some transformation to be properly encoded.

Let see. If we assume uniformly distributed random byte values in our binary data then, on average, half of the bytes would be encoded in one bytes and the other half in two bytes. The UTF-8 encoded binary data would have 150% of the initial size.

Base64 encoding grows only to 133% of the initial size. So Base64 encoding is more efficient.

What about using another Base encoding ? In UTF-8, encoding the 128 ASCII values is the most space efficient. In 8 bits you can store 7 bits. So if we cut the binary data in 7 bit chunks to store them in each byte of an UTF-8 encoded string, the encoded data would grow only to 114% of the initial size. Better than Base64. Unfortunately we can't use this easy trick because JSON doesn't allow some ASCII chars. The 33 control characters of ASCII ( [0..31] and 127) and the " and \ must be excluded. This leaves us only 128-35 = 93 chars.

So in theory we could define a Base93 encoding which would grow the encoded size to 8/log2(93) = 8*log10(2)/log10(93) = 122%. But a Base93 encoding would not be as convenient as a Base64 encoding. Base64 requires to cut the input byte sequence in 6bit chunks for which simple bitwise operation works well. Beside 133% is not much more than 122%.

This is why I came independently to the common conclusion that Base64 is indeed the best choice to encode binary data in JSON. My answer presents a justification for it. I agree it isn't very attractive from the performance point of view, but consider also the benefit of using JSON with it's human readable string representation easy to manipulate in all programming languages.

If performance is critical than a pure binary encoding should be considered as replacement of JSON. But with JSON my conclusion is that Base64 is the best.

How to export data from Excel spreadsheet to Sql Server 2008 table

In SQL Server 2016 the wizard is a separate app. (Important: Excel wizard is only available in the 32-bit version of the wizard!). Use the MSDN page for instructions:

On the Start menu, point to All Programs, point toMicrosoft SQL Server , and then click Import and Export Data.
—or—
In SQL Server Data Tools (SSDT), right-click the SSIS Packages folder, and then click SSIS Import and Export Wizard.
—or—
In SQL Server Data Tools (SSDT), on the Project menu, click SSIS Import and Export Wizard.
—or—
In SQL Server Management Studio, connect to the Database Engine server type, expand Databases, right-click a database, point to Tasks, and then click Import Data or Export data.
—or—
In a command prompt window, run DTSWizard.exe, located in C:\Program Files\Microsoft SQL Server\100\DTS\Binn.

After that it should be pretty much the same (possibly with minor variations in the UI) as in @marc_s's answer.

Clear the cache in JavaScript

You can't clear the cache with javascript. A common way is to append the revision number or last updated timestamp to the file, like this:

myscript.123.js

or

myscript.js?updated=1234567890

Avoiding NullPointerException in Java

Rather than Null Object Pattern -- which has its uses -- you might consider situations where the null object is a bug.

When the exception is thrown, examine the stack trace and work through the bug.

C++: what regex library should I use?

You can also look at fast regex library that was developed at Yandex search engine for doing fast matches of thousands of patterns against huge amounts of data.

Real mouse position in canvas

Refer this question: The mouseEvent.offsetX I am getting is much larger than actual canvas size .I have given a function there which will exactly suit in your situation

Fast way to discover the row count of a table in PostgreSQL

How wide is the text column?

With a GROUP BY there's not much you can do to avoid a data scan (at least an index scan).

I'd recommend:

  1. If possible, changing the schema to remove duplication of text data. This way the count will happen on a narrow foreign key field in the 'many' table.

  2. Alternatively, creating a generated column with a HASH of the text, then GROUP BY the hash column. Again, this is to decrease the workload (scan through a narrow column index)

Edit:

Your original question did not quite match your edit. I'm not sure if you're aware that the COUNT, when used with a GROUP BY, will return the count of items per group and not the count of items in the entire table.

Stupid error: Failed to load resource: net::ERR_CACHE_MISS

We get err_cache_miss error while using the bowser. Its mean there may be a problem with your browser. It due the items in the cache may be unusable or some configurations are not configured correctly. You may get the solution to clear browser data or Check browser extensions and remove extensions which you felt cause the problem or Resetting your browser or Update your browser or Disabling cache system. These are some tricks to come out this error.

Remove non-utf8 characters from string

$text = iconv("UTF-8", "UTF-8//IGNORE", $text);

This is what I am using. Seems to work pretty well. Taken from http://planetozh.com/blog/2005/01/remove-invalid-characters-in-utf-8/

How to configure Eclipse build path to use Maven dependencies?

For newer Eclipse versions (>=Mars) right click on project > configure > convert to Maven project

Why is IoC / DI not common in Python?

I don't actually think that DI/IoC are that uncommon in Python. What is uncommon, however, are DI/IoC frameworks/containers.

Think about it: what does a DI container do? It allows you to

  1. wire together independent components into a complete application ...
  2. ... at runtime.

We have names for "wiring together" and "at runtime":

  1. scripting
  2. dynamic

So, a DI container is nothing but an interpreter for a dynamic scripting language. Actually, let me rephrase that: a typical Java/.NET DI container is nothing but a crappy interpreter for a really bad dynamic scripting language with butt-ugly, sometimes XML-based, syntax.

When you program in Python, why would you want to use an ugly, bad scripting language when you have a beautiful, brilliant scripting language at your disposal? Actually, that's a more general question: when you program in pretty much any language, why would you want to use an ugly, bad scripting language when you have Jython and IronPython at your disposal?

So, to recap: the practice of DI/IoC is just as important in Python as it is in Java, for exactly the same reasons. The implementation of DI/IoC however, is built into the language and often so lightweight that it completely vanishes.

(Here's a brief aside for an analogy: in assembly, a subroutine call is a pretty major deal - you have to save your local variables and registers to memory, save your return address somewhere, change the instruction pointer to the subroutine you are calling, arrange for it to somehow jump back into your subroutine when it is finished, put the arguments somewhere where the callee can find them, and so on. IOW: in assembly, "subroutine call" is a Design Pattern, and before there were languages like Fortran which had subroutine calls built in, people were building their own "subroutine frameworks". Would you say that subroutine calls are "uncommon" in Python, just because you don't use subroutine frameworks?)

BTW: for an example of what it looks like to take DI to its logical conclusion, take a look at Gilad Bracha's Newspeak Programming Language and his writings on the subject: