Programs & Examples On #Ftell

ftell is a standard C library function which returns the current offset in a file or stream in relation to the first byte.

How to resolve the "EVP_DecryptFInal_ex: bad decrypt" during file decryption

I experienced a similar error reply while using the openssl command line interface, while having the correct binary key (-K). The option "-nopad" resolved the issue:

Example generating the error:

echo -ne "\x32\xc8\xde\x5c\x68\x19\x7e\x53\xa5\x75\xe1\x76\x1d\x20\x16\xb2\x72\xd8\x40\x87\x25\xb3\x71\x21\x89\xf6\xca\x46\x9f\xd0\x0d\x08\x65\x49\x23\x30\x1f\xe0\x38\x48\x70\xdb\x3b\xa8\x56\xb5\x4a\xc6\x09\x9e\x6c\x31\xce\x60\xee\xa2\x58\x72\xf6\xb5\x74\xa8\x9d\x0c" | openssl aes-128-cbc -d -K 31323334353637383930313233343536 -iv 79169625096006022424242424242424 | od -t x1

Result:

bad decrypt
140181876450560:error:06065064:digital envelope 
routines:EVP_DecryptFinal_ex:bad decrypt:../crypto/evp/evp_enc.c:535:
0000000 2f 2f 07 02 54 0b 00 00 00 00 00 00 04 29 00 00
0000020 00 00 04 a9 ff 01 00 00 00 00 04 a9 ff 02 00 00
0000040 00 00 04 a9 ff 03 00 00 00 00 0d 79 0a 30 36 38

Example with correct result:

echo -ne "\x32\xc8\xde\x5c\x68\x19\x7e\x53\xa5\x75\xe1\x76\x1d\x20\x16\xb2\x72\xd8\x40\x87\x25\xb3\x71\x21\x89\xf6\xca\x46\x9f\xd0\x0d\x08\x65\x49\x23\x30\x1f\xe0\x38\x48\x70\xdb\x3b\xa8\x56\xb5\x4a\xc6\x09\x9e\x6c\x31\xce\x60\xee\xa2\x58\x72\xf6\xb5\x74\xa8\x9d\x0c" | openssl aes-128-cbc -d -K 31323334353637383930313233343536 -iv 79169625096006022424242424242424 -nopad | od -t x1

Result:

0000000 2f 2f 07 02 54 0b 00 00 00 00 00 00 04 29 00 00
0000020 00 00 04 a9 ff 01 00 00 00 00 04 a9 ff 02 00 00
0000040 00 00 04 a9 ff 03 00 00 00 00 0d 79 0a 30 36 38
0000060 30 30 30 34 31 33 31 2f 2f 2f 2f 2f 2f 2f 2f 2f
0000100

Read from file or stdin

Note that what you want is to know if stdin is connected to a terminal or not, not if it exists. It always exists but when you use the shell to pipe something into it or read a file, it is not connected to a terminal.

You can check that a file descriptor is connected to a terminal via the termios.h functions:

#include <termios.h>
#include <stdbool.h>

bool stdin_is_a_pipe(void)
{
    struct termios t;
    return (tcgetattr(STDIN_FILENO, &t) < 0);
}

This will try to fetch the terminal attributes of stdin. If it is not connected to a pipe, it is attached to a tty and the tcgetattr function call will succeed. In order to detect a pipe, we check for tcgetattr failure.

Can pm2 run an 'npm start' script

Yes we can, now pm2 support npm start, --name to species app name.

pm2 start npm --name "app" -- start

In C#, why is String a reference type that behaves like a value type?

It is mainly a performance issue.

Having strings behave LIKE value type helps when writing code, but having it BE a value type would make a huge performance hit.

For an in-depth look, take a peek at a nice article on strings in the .net framework.

No notification sound when sending notification from firebase in android

I am able to play notification sound even if I send it from firebase console. To do that you just need to add key "sound" with value "default" in advance option.

How do I set up CLion to compile and run?

I met some problems in Clion and finally, I solved them. Here is some experience.

  1. Download and install MinGW
  2. g++ and gcc package should be installed by default. Use the MinGW installation manager to install mingw32-libz and mingw32-make. You can open MinGW installation manager through C:\MinGW\libexec\mingw-get.exe This step is the most important step. If Clion cannot find make, C compiler and C++ compiler, recheck the MinGW installation manager to make every necessary package is installed.
  3. In Clion, open File->Settings->Build,Execution,Deployment->Toolchains. Set MinGW home as your local MinGW file.
  4. Start your "Hello World"!

maven "cannot find symbol" message unhelpful

I had the same problem. The reason was that I had two JAR files were not added through the Maven dependency, so when I ran mvn compile, the console display the error error:

Symbol cannot be found,Class...".

To fix it:

  1. Remove the JAR files from build path
  2. Add to build path
  3. Run mvn compile

How to select option in drop down using Capybara

Here's the most concise way I've found (using capybara 3.3.0 and chromium driver):

all('#id-of-select option')[1].select_option

will select the 2nd option. Increment the index as needed.

^[A-Za-Z ][A-Za-z0-9 ]* regular expression?

^[A-Za-z](\W|\w)*

(\W|\w) will ensure that every subsequent letter is word(\w) or non word(\W)

instead of (\W|\w)* you can also use .* where . means absolutely anything just like (\w|\W)

jquery, domain, get URL

//If url is something.domain.com this returns -> domain.com
function getDomain() {
  return window.location.hostname.replace(/([a-zA-Z0-9]+.)/,"");
}

How can I specify the required Node.js version in package.json?

Just like said Ibam, engineStrict is now deprecated. But I've found this solution:

check-version.js:

import semver from 'semver';
import { engines } from './package';

const version = engines.node;
if (!semver.satisfies(process.version, version)) {
  console.log(`Required node version ${version} not satisfied with current version ${process.version}.`);
  process.exit(1);
}

package.json:

{
  "name": "my package",
  "engines": {
    "node": ">=50.9" // intentionally so big version number
  },
  "scripts": {
    "requirements-check": "babel-node check-version.js",
    "postinstall": "npm run requirements-check"
  }
}

Find out more here: https://medium.com/@adambisek/how-to-check-minimum-required-node-js-version-4a78a8855a0f#.3oslqmig4

.nvmrc

And one more thing. A dotfile '.nvmrc' can be used for requiring specific node version - https://github.com/creationix/nvm#nvmrc

But, it is only respected by npm scripts (and yarn scripts).

How can I record a Video in my Android App.?

Here is another example which is working

public class EnregistrementVideoStackActivity extends Activity implements SurfaceHolder.Callback {
    private SurfaceHolder surfaceHolder;
    private SurfaceView surfaceView;
    public MediaRecorder mrec = new MediaRecorder();
    private Button startRecording = null;

    File video;
    private Camera mCamera;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.camera_surface);
        Log.i(null , "Video starting");
        startRecording = (Button)findViewById(R.id.buttonstart);
        mCamera = Camera.open();
        surfaceView = (SurfaceView) findViewById(R.id.surface_camera);
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);
        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu)
    {
        menu.add(0, 0, 0, "StartRecording");
        menu.add(0, 1, 0, "StopRecording");
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item)
    {
        switch (item.getItemId())
        {
        case 0:
            try {
                startRecording();
            } catch (Exception e) {
                String message = e.getMessage();
                Log.i(null, "Problem Start"+message);
                mrec.release();
            }
            break;

        case 1: //GoToAllNotes
            mrec.stop();
            mrec.release();
            mrec = null;
            break;

        default:
            break;
        }
        return super.onOptionsItemSelected(item);
    }

    protected void startRecording() throws IOException 
    {
        mrec = new MediaRecorder();  // Works well
        mCamera.unlock();

        mrec.setCamera(mCamera);

        mrec.setPreviewDisplay(surfaceHolder.getSurface());
        mrec.setVideoSource(MediaRecorder.VideoSource.CAMERA);
        mrec.setAudioSource(MediaRecorder.AudioSource.MIC); 

        mrec.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_HIGH));
        mrec.setPreviewDisplay(surfaceHolder.getSurface());
        mrec.setOutputFile("/sdcard/zzzz.3gp"); 

        mrec.prepare();
        mrec.start();
    }

    protected void stopRecording() {
        mrec.stop();
        mrec.release();
        mCamera.release();
    }

    private void releaseMediaRecorder(){
        if (mrec != null) {
            mrec.reset();   // clear recorder configuration
            mrec.release(); // release the recorder object
            mrec = null;
            mCamera.lock();           // lock camera for later use
        }
    }

    private void releaseCamera(){
        if (mCamera != null){
            mCamera.release();        // release the camera for other applications
            mCamera = null;
        }
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        if (mCamera != null){
            Parameters params = mCamera.getParameters();
            mCamera.setParameters(params);
        }
        else {
            Toast.makeText(getApplicationContext(), "Camera not available!", Toast.LENGTH_LONG).show();
            finish();
        }
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        mCamera.stopPreview();
        mCamera.release();
    }
}

camera_surface.xml

<?xml version="1.0" encoding="UTF-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<SurfaceView
    android:id="@+id/surface_camera"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weight="1" />

<Button
    android:id="@+id/buttonstart"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/record_start" />

</RelativeLayout>

And of course include these permission in manifest:

<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

string to string array conversion in java

You could use string.chars().mapToObj(e -> new String(new char[] {e}));, though this is quite lengthy and only works with java 8. Here are a few more methods:

string.split(""); (Has an extra whitespace character at the beginning of the array if used before Java 8) string.split("|"); string.split("(?!^)"); Arrays.toString(string.toCharArray()).substring(1, string.length() * 3 + 1).split(", ");

The last one is just unnecessarily long, it's just for fun!

Apache Proxy: No protocol handler was valid

I tried to get an uwsgi:// working, but somehow the manual thought it was clear to me that I actually needed mod_proxy_uwsgi. It was not. Here is how you do it: How to compile mod_proxy_uwsgi or mod_uwsgi?

How to write a CSS hack for IE 11?

So I found my own solution to this problem in the end.

After searching through Microsoft documentation I managed to find a new IE11 only style msTextCombineHorizontal

In my test, I check for IE10 styles and if they are a positive match, then I check for the IE11 only style. If I find it, then it's IE11+, if I don't, then it's IE10.

Code Example: Detect IE10 and IE11 by CSS Capability Testing (JSFiddle)

I will update the code example with more styles when I discover them.

NOTE: This will almost certainly identify IE12 and IE13 as "IE11", as those styles will probably carry forward. I will add further tests as new versions roll out, and hopefully be able to rely again on Modernizr.

I'm using this test for fallback behavior. The fallback behavior is just less glamorous styling, it doesn't have reduced functionality.

How to use css style in php

I guess you have your css code in a database & you want to render a php file as a CSS. If that is the case...

In your html page:

<html>
<head>
   <!- head elements (Meta, title, etc) -->

   <!-- Link your php/css file -->
   <link rel="stylesheet" href="style.php" media="screen">
<head>

Then, within style.php file:

<?php
/*** set the content type header ***/
/*** Without this header, it wont work ***/
header("Content-type: text/css");


$font_family = 'Arial, Helvetica, sans-serif';
$font_size = '0.7em';
$border = '1px solid';
?>

table {
margin: 8px;
}

th {
font-family: <?=$font_family?>;
font-size: <?=$font_size?>;
background: #666;
color: #FFF;
padding: 2px 6px;
border-collapse: separate;
border: <?=$border?> #000;
}

td {
font-family: <?=$font_family?>;
font-size: <?=$font_size?>;
border: <?=$border?> #DDD;
}

Have fun!

Merging multiple PDFs using iTextSharp in c#.net

Using iTextSharp.dll

protected void Page_Load(object sender, EventArgs e)
{
    String[] files = @"C:\ENROLLDOCS\A1.pdf,C:\ENROLLDOCS\A2.pdf".Split(',');
    MergeFiles(@"C:\ENROLLDOCS\New1.pdf", files);
}
public void MergeFiles(string destinationFile, string[] sourceFiles)
{
    if (System.IO.File.Exists(destinationFile))
        System.IO.File.Delete(destinationFile);

    string[] sSrcFile;
    sSrcFile = new string[2];

    string[] arr = new string[2];
    for (int i = 0; i <= sourceFiles.Length - 1; i++)
    {
        if (sourceFiles[i] != null)
        {
            if (sourceFiles[i].Trim() != "")
                arr[i] = sourceFiles[i].ToString();
        }
    }

    if (arr != null)
    {
        sSrcFile = new string[2];

        for (int ic = 0; ic <= arr.Length - 1; ic++)
        {
            sSrcFile[ic] = arr[ic].ToString();
        }
    }
    try
    {
        int f = 0;

        PdfReader reader = new PdfReader(sSrcFile[f]);
        int n = reader.NumberOfPages;
        Response.Write("There are " + n + " pages in the original file.");
        Document document = new Document(PageSize.A4);

        PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(destinationFile, FileMode.Create));

        document.Open();
        PdfContentByte cb = writer.DirectContent;
        PdfImportedPage page;

        int rotation;
        while (f < sSrcFile.Length)
        {
            int i = 0;
            while (i < n)
            {
                i++;

                document.SetPageSize(PageSize.A4);
                document.NewPage();
                page = writer.GetImportedPage(reader, i);

                rotation = reader.GetPageRotation(i);
                if (rotation == 90 || rotation == 270)
                {
                    cb.AddTemplate(page, 0, -1f, 1f, 0, 0, reader.GetPageSizeWithRotation(i).Height);
                }
                else
                {
                    cb.AddTemplate(page, 1f, 0, 0, 1f, 0, 0);
                }
                Response.Write("\n Processed page " + i);
            }

            f++;
            if (f < sSrcFile.Length)
            {
                reader = new PdfReader(sSrcFile[f]);
                n = reader.NumberOfPages;
                Response.Write("There are " + n + " pages in the original file.");
            }
        }
        Response.Write("Success");
        document.Close();
    }
    catch (Exception e)
    {
        Response.Write(e.Message);
    }


}

How to check if a file exists in Documents folder?

Swift 2.0

This is how to check if the file exists using Swift

func isFileExistsInDirectory() -> Bool {
    let paths = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true)
    let documentsDirectory: AnyObject = paths[0]
    let dataPath = documentsDirectory.stringByAppendingPathComponent("/YourFileName")

    return NSFileManager.defaultManager().fileExistsAtPath(dataPath)
}

Remove a data connection from an Excel 2010 spreadsheet in compatibility mode

I had the same problem today. If after you delete all of the connections, the connection properties still live on. I clicked on properties, deleted the name by selecting the name window and deleting it.

A warning came up to verify I really wanted to do it. After selecting yes, it got rid of the connection. Save the workbook.

I am a hack at Excel but this seemed to work.

How to get CPU temperature?

It's depends on if your computer support WMI. My computer can't run this WMI demo too.

But I successfully get the CPU temperature via Open Hardware Monitor. Add the Openhardwaremonitor reference in Visual Studio. It's easier. Try this

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using OpenHardwareMonitor.Hardware;
namespace Get_CPU_Temp5
{
   class Program
   {
       public class UpdateVisitor : IVisitor
       {
           public void VisitComputer(IComputer computer)
           {
               computer.Traverse(this);
           }
           public void VisitHardware(IHardware hardware)
           {
               hardware.Update();
               foreach (IHardware subHardware in hardware.SubHardware) subHardware.Accept(this);
           }
           public void VisitSensor(ISensor sensor) { }
           public void VisitParameter(IParameter parameter) { }
       }
       static void GetSystemInfo()
       {
           UpdateVisitor updateVisitor = new UpdateVisitor();
           Computer computer = new Computer();
           computer.Open();
           computer.CPUEnabled = true;
           computer.Accept(updateVisitor);
           for (int i = 0; i < computer.Hardware.Length; i++)
           {
               if (computer.Hardware[i].HardwareType == HardwareType.CPU)
               {
                   for (int j = 0; j < computer.Hardware[i].Sensors.Length; j++)
                   {
                       if (computer.Hardware[i].Sensors[j].SensorType == SensorType.Temperature)
                               Console.WriteLine(computer.Hardware[i].Sensors[j].Name + ":" + computer.Hardware[i].Sensors[j].Value.ToString() + "\r");
                   }
               }
           }
           computer.Close();
       }
       static void Main(string[] args)
       {
           while (true)
           {
               GetSystemInfo();
           }
       }
   }
}

You need to run this demo as administrator.

You can see the tutorial here: http://www.lattepanda.com/topic-f11t3004.html

How to write a simple Java program that finds the greatest common divisor between two numbers?

public static int GCD(int x, int y) {   
    int r;
    while (y!=0) {
        r = x%y;
        x = y;
        y = r;
    }
    return x;
}

Convert a String of Hex into ASCII in Java

Check out Convert a string representation of a hex dump to a byte array using Java?

Disregarding encoding, etc. you can do new String (hexStringToByteArray("75546..."));

HTML button to NOT submit form

I think this is the most annoying little peculiarity of HTML... That button needs to be of type "button" in order to not submit.

<button type="button">My Button</button>

Update 5-Feb-2019: As per the HTML Living Standard (and also HTML 5 specification):

The missing value default and invalid value default are the Submit Button state.

How do I escape a string inside JavaScript code inside an onClick handler?

If it's going into an HTML attribute, you'll need to both HTML-encode (as a minimum: > to &gt; < to &lt and " to &quot;) it, and escape single-quotes (with a backslash) so they don't interfere with your javascript quoting.

Best way to do it is with your templating system (extending it, if necessary), but you could simply make a couple of escaping/encoding functions and wrap them both around any data that's going in there.

And yes, it's perfectly valid (correct, even) to HTML-escape the entire contents of your HTML attributes, even if they contain javascript.

How to add 10 days to current time in Rails

This definitely works and I use this wherever I need to add days to the current date:

Date.today + 5

How to check if spark dataframe is empty?

dataframe.limit(1).count > 0

This also triggers a job but since we are selecting single record, even in case of billion scale records the time consumption could be much lower.

From: https://medium.com/checking-emptiness-in-distributed-objects/count-vs-isempty-surprised-to-see-the-impact-fa70c0246ee0

How do I get the object if it exists, or None if it does not exist?

Without exception:

if SomeModel.objects.filter(foo='bar').exists():
    x = SomeModel.objects.get(foo='bar')
else:
    x = None

Using an exception:

try:
   x = SomeModel.objects.get(foo='bar')
except SomeModel.DoesNotExist:
   x = None

There is a bit of an argument about when one should use an exception in python. On the one hand, "it is easier to ask for forgiveness than for permission". While I agree with this, I believe that an exception should remain, well, the exception, and the "ideal case" should run without hitting one.

how to use javascript Object.defineProperty

Since you asked a similar question, let's take it to step by step. It's a bit longer, but it may save you much more time than I have spent on writing this:

Property is an OOP feature designed for clean separation of client code. For example, in some e-shop you might have objects like this:

function Product(name,price) {
  this.name = name;
  this.price = price;
  this.discount = 0;
}

var sneakers = new Product("Sneakers",20); // {name:"Sneakers",price:20,discount:0}
var tshirt = new Product("T-shirt",10);  // {name:"T-shirt",price:10,discount:0}

Then in your client code (the e-shop), you can add discounts to your products:

function badProduct(obj) { obj.discount+= 20; ... }
function generalDiscount(obj) { obj.discount+= 10; ... }
function distributorDiscount(obj) { obj.discount+= 15; ... }

Later, the e-shop owner might realize that the discount can't be greater than say 80%. Now you need to find EVERY occurrence of the discount modification in the client code and add a line

if(obj.discount>80) obj.discount = 80;

Then the e-shop owner may further change his strategy, like "if the customer is reseller, the maximal discount can be 90%". And you need to do the change on multiple places again plus you need to remember to alter these lines anytime the strategy is changed. This is a bad design. That's why encapsulation is the basic principle of OOP. If the constructor was like this:

function Product(name,price) {
  var _name=name, _price=price, _discount=0;
  this.getName = function() { return _name; }
  this.setName = function(value) { _name = value; }
  this.getPrice = function() { return _price; }
  this.setPrice = function(value) { _price = value; }
  this.getDiscount = function() { return _discount; }
  this.setDiscount = function(value) { _discount = value; } 
}

Then you can just alter the getDiscount (accessor) and setDiscount (mutator) methods. The problem is that most of the members behave like common variables, just the discount needs special care here. But good design requires encapsulation of every data member to keep the code extensible. So you need to add lots of code that does nothing. This is also a bad design, a boilerplate antipattern. Sometimes you can't just refactor the fields to methods later (the eshop code may grow large or some third-party code may depend on the old version), so the boilerplate is lesser evil here. But still, it is evil. That's why properties were introduced into many languages. You could keep the original code, just transform the discount member into a property with get and set blocks:

function Product(name,price) {
  this.name = name;
  this.price = price;
//this.discount = 0; // <- remove this line and refactor with the code below
  var _discount; // private member
  Object.defineProperty(this,"discount",{
    get: function() { return _discount; },
    set: function(value) { _discount = value; if(_discount>80) _discount = 80; }
  });
}

// the client code
var sneakers = new Product("Sneakers",20);
sneakers.discount = 50; // 50, setter is called
sneakers.discount+= 20; // 70, setter is called
sneakers.discount+= 20; // 80, not 90!
alert(sneakers.discount); // getter is called

Note the last but one line: the responsibility for correct discount value was moved from the client code (e-shop definition) to the product definition. The product is responsible for keeping its data members consistent. Good design is (roughly said) if the code works the same way as our thoughts.

So much about properties. But javascript is different from pure Object-oriented languages like C# and codes the features differently:

In C#, transforming fields into properties is a breaking change, so public fields should be coded as Auto-Implemented Properties if your code might be used in the separately compiled client.

In Javascript, the standard properties (data member with getter and setter described above) are defined by accessor descriptor (in the link you have in your question). Exclusively, you can use data descriptor (so you can't use i.e. value and set on the same property):

  • accessor descriptor = get + set (see the example above)
    • get must be a function; its return value is used in reading the property; if not specified, the default is undefined, which behaves like a function that returns undefined
    • set must be a function; its parameter is filled with RHS in assigning a value to property; if not specified, the default is undefined, which behaves like an empty function
  • data descriptor = value + writable (see the example below)
    • value default undefined; if writable, configurable and enumerable (see below) are true, the property behaves like an ordinary data field
    • writable - default false; if not true, the property is read only; attempt to write is ignored without error*!

Both descriptors can have these members:

  • configurable - default false; if not true, the property can't be deleted; attempt to delete is ignored without error*!
  • enumerable - default false; if true, it will be iterated in for(var i in theObject); if false, it will not be iterated, but it is still accessible as public

* unless in strict mode - in that case JS stops execution with TypeError unless it is caught in try-catch block

To read these settings, use Object.getOwnPropertyDescriptor().

Learn by example:

var o = {};
Object.defineProperty(o,"test",{
  value: "a",
  configurable: true
});
console.log(Object.getOwnPropertyDescriptor(o,"test")); // check the settings    

for(var i in o) console.log(o[i]); // nothing, o.test is not enumerable
console.log(o.test); // "a"
o.test = "b"; // o.test is still "a", (is not writable, no error)
delete(o.test); // bye bye, o.test (was configurable)
o.test = "b"; // o.test is "b"
for(var i in o) console.log(o[i]); // "b", default fields are enumerable

If you don't wish to allow the client code such cheats, you can restrict the object by three levels of confinement:

  • Object.preventExtensions(yourObject) prevents new properties to be added to yourObject. Use Object.isExtensible(<yourObject>) to check if the method was used on the object. The prevention is shallow (read below).
  • Object.seal(yourObject) same as above and properties can not be removed (effectively sets configurable: false to all properties). Use Object.isSealed(<yourObject>) to detect this feature on the object. The seal is shallow (read below).
  • Object.freeze(yourObject) same as above and properties can not be changed (effectively sets writable: false to all properties with data descriptor). Setter's writable property is not affected (since it doesn't have one). The freeze is shallow: it means that if the property is Object, its properties ARE NOT frozen (if you wish to, you should perform something like "deep freeze", similar to deep copy - cloning). Use Object.isFrozen(<yourObject>) to detect it.

You don't need to bother with this if you write just a few lines fun. But if you want to code a game (as you mentioned in the linked question), you should care about good design. Try to google something about antipatterns and code smell. It will help you to avoid situations like "Oh, I need to completely rewrite my code again!", it can save you months of despair if you want to code a lot. Good luck.

Button Center CSS

Another nice option is to use :

width: 40%;
margin-left: 30%;
margin-right: 30%

How to execute a * .PY file from a * .IPYNB file on the Jupyter notebook?

Maybe not very elegant, but it does the job:

exec(open("script.py").read())

Apple Mach-O Linker Error when compiling for device

Just ran into the same issue.

The solution (for me) = check your frameworks.

In my case I had added classes related to CoreData without "CoreData.framework". Adding it solved the MACH_O complaining.

Creating a new ArrayList in Java

Fixed the code for you:

ArrayList<Class> myArray= new ArrayList<Class>();

How to make Bootstrap Panel body with fixed height

HTML :

<div class="span4">
  <div class="panel panel-primary">
    <div class="panel-heading">jhdsahfjhdfhs</div>
    <div class="panel-body panel-height">fdoinfds sdofjohisdfj</div>
  </div>
</div>

CSS :

.panel-height {
  height: 100px; / change according to your requirement/
}

Replace string within file contents

with open("Stud.txt", "rt") as fin:
    with open("out.txt", "wt") as fout:
        for line in fin:
            fout.write(line.replace('A', 'Orange'))

collapse cell in jupyter notebook

UPDATE:

The newer jupyter-lab is a more modern and feature-rich interface which supports cell folding by default. See @intsco's answer below

Original answer:

The jupyter contrib nbextensions Python package contains a code-folding extension that can be enabled within the notebook. Follow the link (Github) for documentation.

To install using command line:

pip install jupyter_contrib_nbextensions
jupyter contrib nbextension install --user

To make life easier in managing them, I'd also recommend the jupyter nbextensions configurator package. This provides an extra tab in your Notebook interface from where you can easily (de)activate all installed extensions.

Installation:

pip install jupyter_nbextensions_configurator
jupyter nbextensions_configurator enable --user

Execute a stored procedure in another stored procedure in SQL server

If you only want to perform some specific operations by your second SP and do not require values back from the SP then simply do:

Exec secondSPName  @anyparams

Else, if you need values returned by your second SP inside your first one, then create a temporary table variable with equal numbers of columns and with same definition of column return by second SP. Then you can get these values in first SP as:

Insert into @tep_table
Exec secondSPName @anyparams

Update:

To pass parameter to second sp, do this:

Declare @id ID_Column_datatype 
Set @id=(Select id from table_1 Where yourconditions)

Exec secondSPName @id

Update 2:

Suppose your second sp returns Id and Name where type of id is int and name is of varchar(64) type.

now, if you want to select these values in first sp then create a temporary table variable and insert values into it:

Declare @tep_table table
(
  Id int,
  Name varchar(64)
)
Insert into @tep_table
Exec secondSP

Select * From @tep_table

This will return you the values returned by second SP.

Hope, this clear all your doubts.

Why do people use Heroku when AWS is present? What distinguishes Heroku from AWS?

The existing answers are broadly accurate:

  • Heroku is very easy to use and deploy to, can be easily configured for auto-deployment a repository (eg GitHub), has lots of third party add-ons and charges more per instance.

  • AWS has a wider range of competitively priced first party services including DNS, load balancing, cheap file storage and has enterprise features like being able to define security policies.

For the tl;dr skip to the end of this post.

AWS ElasticBeanstalk is an attempt to provide a Heroku-like autoscaling and easy deployment platform. As it uses EC2 instances (which it creates automatically) EB servers can do everything any other EC2 instance can do and it's cheap to run.

Deployment with EB is very slow; deploying an update can take 10-15 minutes per server and deploying to a larger cluster can take the best part of an hour - compared to just seconds to deploy an update on Heroku. Deployments on EB are not handled particularly seamlessly either, which may impose constraints on application design.

You can use all the services ElasticBeanstalk uses behind the scenes to build your own bespoke system (with CodeDeploy, Elastic Load Balancer, Auto Scaling Groups - and CodeCommit, CodeBuild and CodePipeline if you want to go all in) but you can definitely spend a good couple of weeks setting it up the the first time as it's fairly convoluted and slightly tricker than just configuring things in EC2.

AWS Lightsail offers a competitively priced hosting option, but doesn't help with deployment or scaling - it's really just a wrapper for their EC2 offering (but costs much more). It lets you automatically run a bash script on initial setup, which is nice touch but it's pricy compared to the cost of just setting up an EC2 instance (which you can also do programmatically).

Some thoughts on comparing (to try and answer the questions, albeit in a roundabout way):

  1. Don't underestimate how much work system administration is, including keeping everything you have installed up to date with security patches (and occasional OS updates).

  2. Don't underestimate how much of a benefit automatic deployment, auto-scaling, and SSL provisioning and configuration are.

    Automatic deployment when you update your Git repository is effortless with Heroku. It is near instant, graceful so there are no outages for end users and can be set to update only if the tests / Continuous Integration passes so you don't break your site if you deploy broken code.

    You can also use ElasticBeanstalk for automatic deployment, but be prepared to spend a week setting that up the first time - you may have to change how you deploy and build assets (like CSS and JS) to work with how ElasticBeanstalk handles deployments or build logic into your app to handle deployments.

    Be aware in estimating costs that for seamless deployment with no outage on EB you need to run multiple instances - EB rolls out updates to each server individually so that your service is not degraded - where as Heroku spins up a new dyno for you and just deprecates the old service until all the requests to it are done being handled (then it deletes it).

    Interestingly, the hosting cost of running multiple servers with EB can be cheaper than a single Heroku instance, especially once you include the cost of add-ons.

Some other issues not specifically asked about, but raised by other answers:

  1. Using a different provider for production and development is a bad idea.

    I am cringing that people are suggesting this. While ideally code should run just fine on any reasonable platform so it's as portable as possible, versions of software on each host will vary greatly and just because code runs in staging doesn't mean it will run in production (e.g. major Node.js/Ruby/Python/PHP/Perl versions can differ in ways that make code incompatible, often in silent ways that might not be caught even if you have decent test coverage).

    What is a good idea is to leverage something like Heroku for prototyping, smaller projects and microsites - so you can build and deploy things quickly without investing a lot of time in configuration and maintenance.

    Be sure to factor in the cost of running both production and pre-production instances when making that decision, not forgetting the cost of replicating the entire environment (including third party services such as data stores / add ons, installing and configuring SSL, etc).

  2. If using AWS, be wary of AWS pre-configured instances from vendors like Bitnami - they are a security nightmare. They can expose lots of notoriously vulnerable applications by default without mentioning it in the description.

    Consider instead just using a well supported mainstream distribution, such as Ubuntu or Debian (or CentOS if you need RPM support).

    Note: Amazon offer have their own distribution called Amazon Linux, which uses RPM, but it's EC2 specific and less well supported by third party/open source software.

  3. You could also setup an EC2 instance on AWS (or Lightsail) and configure with something like flynn or dokku on it - on which you could then deploy multiple sites easily, which can be worth it if you maintain a lot of services or want to be able to spin up new things easily. However getting it set up is not as automagic as just using Heroku and you can end up spending a lot of time configuring and maintaining it (to the point I've found deploying using Amazon clustering and Docker Swarm to be easier than setting them up; YMMV).

I have used AWS EC instances (alone and in clusters), Elastic Beanstalk and Lightsail and Heroku at the same time depending on the needs of the project I'm working on.

I hate spending time configuring services but my Heroku bill would be thousands per year if I used it for everything and AWS works out a fraction of the cost.

tl;dr

If money was never an issue I'd use Heroku for almost everything as it's a huge timesaver - but I'd still want to use AWS for more complicated projects where I need the flexibility and more advanced services that Heroku doesn't offer.

The ideal scenario for me would be if ElasticBeanstalk just worked more like Heroku - i.e. with easier configuration and quicker and a better deployment mechanism.

An example of a service that is almost this is now.sh, which actually uses AWS behind the scenes, but makes deployments and clustering as easy as it is on Heroku (with automatic SSL, DNS, graceful deployments, super-easy cluster setup and management).

I've used it quite lot for both Node.js app and Docker image deployments, the major caveat is the instances are shared (something reflected in their lower cost) and currently no option to buy dedicated instances. However their open source deployment tool 'now' can also be used to deploy to dedicated instances on AWS as well as Google Cloud and Azure.

How do I check what version of Python is running my script?

Your best bet is probably something like so:

>>> import sys
>>> sys.version_info
(2, 6, 4, 'final', 0)
>>> if not sys.version_info[:2] == (2, 6):
...    print "Error, I need python 2.6"
... else:
...    from my_module import twoPointSixCode
>>> 

Additionally, you can always wrap your imports in a simple try, which should catch syntax errors. And, to @Heikki's point, this code will be compatible with much older versions of python:

>>> try:
...     from my_module import twoPointSixCode
... except Exception: 
...     print "can't import, probably because your python is too old!"
>>>

100% width background image with an 'auto' height

Tim S. was much closer to a "correct" answer then the currently accepted one. If you want to have a 100% width, variable height background image done with CSS, instead of using cover (which will allow the image to extend out from the sides) or contain (which does not allow the image to extend out at all), just set the CSS like so:

body {
    background-image: url(img.jpg);
    background-position: center top;
    background-size: 100% auto;
}

This will set your background image to 100% width and allow the height to overflow. Now you can use media queries to swap out that image instead of relying on JavaScript.

EDIT: I just realized (3 months later) that you probably don't want the image to overflow; you seem to want the container element to resize based on it's background-image (to preserve it's aspect ratio), which is not possible with CSS as far as I know.

Hopefully soon you'll be able to use the new srcset attribute on the img element. If you want to use img elements now, the currently accepted answer is probably best.

However, you can create a responsive background-image element with a constant aspect ratio using purely CSS. To do this, you set the height to 0 and set the padding-bottom to a percentage of the element's own width, like so:

.foo {
    height: 0;
    padding: 0; /* remove any pre-existing padding, just in case */
    padding-bottom: 75%; /* for a 4:3 aspect ratio */
    background-image: url(foo.png);
    background-position: center center;
    background-size: 100%;
    background-repeat: no-repeat;
}

In order to use different aspect ratios, divide the height of the original image by it's own width, and multiply by 100 to get the percentage value. This works because padding percentage is always calculated based on width, even if it's vertical padding.

Styling the last td in a table with css

Javascript is the only viable way to do this client side (that is, CSS won't help you). In jQuery:

$("table td:last").css("border", "none");

How is the AND/OR operator represented as in Regular Expressions?

Not an expert in regex, but you can do ^((part1|part2)|(part1, part2))$. In words: "part 1 or part2 or both"

How to list all AWS S3 objects in a bucket using Java

Listing Keys Using the AWS SDK for Java

http://docs.aws.amazon.com/AmazonS3/latest/dev/ListingObjectKeysUsingJava.html

import java.io.IOException;
import com.amazonaws.AmazonClientException;
import com.amazonaws.AmazonServiceException;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.ListObjectsRequest;
import com.amazonaws.services.s3.model.ListObjectsV2Request;
import com.amazonaws.services.s3.model.ListObjectsV2Result;
import com.amazonaws.services.s3.model.ObjectListing;
import com.amazonaws.services.s3.model.S3ObjectSummary;

public class ListKeys {
    private static String bucketName = "***bucket name***";

    public static void main(String[] args) throws IOException {
        AmazonS3 s3client = new AmazonS3Client(new ProfileCredentialsProvider());
        try {
            System.out.println("Listing objects");
            final ListObjectsV2Request req = new ListObjectsV2Request().withBucketName(bucketName);
            ListObjectsV2Result result;
            do {               
               result = s3client.listObjectsV2(req);

               for (S3ObjectSummary objectSummary : 
                   result.getObjectSummaries()) {
                   System.out.println(" - " + objectSummary.getKey() + "  " +
                           "(size = " + objectSummary.getSize() + 
                           ")");
               }
               System.out.println("Next Continuation Token : " + result.getNextContinuationToken());
               req.setContinuationToken(result.getNextContinuationToken());
            } while(result.isTruncated() == true ); 

         } catch (AmazonServiceException ase) {
            System.out.println("Caught an AmazonServiceException, " +
                    "which means your request made it " +
                    "to Amazon S3, but was rejected with an error response " +
                    "for some reason.");
            System.out.println("Error Message:    " + ase.getMessage());
            System.out.println("HTTP Status Code: " + ase.getStatusCode());
            System.out.println("AWS Error Code:   " + ase.getErrorCode());
            System.out.println("Error Type:       " + ase.getErrorType());
            System.out.println("Request ID:       " + ase.getRequestId());
        } catch (AmazonClientException ace) {
            System.out.println("Caught an AmazonClientException, " +
                    "which means the client encountered " +
                    "an internal error while trying to communicate" +
                    " with S3, " +
                    "such as not being able to access the network.");
            System.out.println("Error Message: " + ace.getMessage());
        }
    }
}

How to determine the last Row used in VBA including blank spaces in between

If sheet contains unused area on the top, UsedRange.Rows.Count is not the maximum row.

This is the correct max row number.

maxrow = Sheets("..name..").UsedRange.Rows(Sheets("..name..").UsedRange.Rows.Count).Row

How do I get the last character of a string using an Excel function?

Looks like the answer above was a little incomplete try the following:-

=RIGHT(A2,(LEN(A2)-(LEN(A2)-1)))

Obviously, this is for cell A2...

What this does is uses a combination of Right and Len - Len is the length of a string and in this case, we want to remove all but one from that... clearly, if you wanted the last two characters you'd change the -1 to -2 etc etc etc.

After the length has been determined and the portion of that which is required - then the Right command will display the information you need.

This works well combined with an IF statement - I use this to find out if the last character of a string of text is a specific character and remove it if it is. See, the example below for stripping out commas from the end of a text string...

=IF(RIGHT(A2,(LEN(A2)-(LEN(A2)-1)))=",",LEFT(A2,(LEN(A2)-1)),A2)

MySQL set current date in a DATETIME field on insert

Using Now() is not a good idea. It only save the current time and date. It will not update the the current date and time, when you update your data. If you want to add the time once, The default value =Now() is best option. If you want to use timestamp. and want to update the this value, each time that row is updated. Then, trigger is best option to use.

  1. http://www.mysqltutorial.org/sql-triggers.aspx
  2. http://www.tutorialspoint.com/plsql/plsql_triggers.htm

These two toturial will help to implement the trigger.

How can I retrieve the remote git address of a repo?

The long boring solution, which is not involved with CLI, you can manually navigate to:

your local repo folder ? .git folder (hidden) ? config file

then choose your text editor to open it and look for url located under the [remote "origin"] section.

Converting date between DD/MM/YYYY and YYYY-MM-DD?

In case you need to convert an entire column of data (from pandas DataFrame), then first convert it (pandas Series) to the datetime format using to_datetime and finally use .dt.strftime:

def conv_dates_series(df, col, old_date_format, new_date_format):

    df[col] = pd.to_datetime(df[col], format=old_date_format).dt.strftime(new_date_format)

    return(df)

Sample usage:

import pandas as pd

test_df = pd.DataFrame({"Dates": ["1900-01-01", "1999-12-31"]})

old_date_format='%d/%m/%Y'
new_date_format='%Y-%m-%d'

conv_dates_series(test_df, "Dates", old_date_format, new_date_format)

jQuery: keyPress Backspace won't fire?

Use keyup instead of keypress. This gets all the key codes when the user presses something

Set focus and cursor to end of text input field / string w. Jquery

You can do this using Input.setSelectionRange, part of the Range API for interacting with text selections and the text cursor:

var searchInput = $('#Search');

// Multiply by 2 to ensure the cursor always ends up at the end;
// Opera sometimes sees a carriage return as 2 characters.
var strLength = searchInput.val().length * 2;

searchInput.focus();
searchInput[0].setSelectionRange(strLength, strLength);

Demo: Fiddle

scale fit mobile web content using viewport meta tag

ok, here is my final solution with 100% native javascript:

<meta id="viewport" name="viewport">

<script type="text/javascript">
//mobile viewport hack
(function(){

  function apply_viewport(){
    if( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent)   ) {

      var ww = window.screen.width;
      var mw = 800; // min width of site
      var ratio =  ww / mw; //calculate ratio
      var viewport_meta_tag = document.getElementById('viewport');
      if( ww < mw){ //smaller than minimum size
        viewport_meta_tag.setAttribute('content', 'initial-scale=' + ratio + ', maximum-scale=' + ratio + ', minimum-scale=' + ratio + ', user-scalable=no, width=' + mw);
      }
      else { //regular size
        viewport_meta_tag.setAttribute('content', 'initial-scale=1.0, maximum-scale=1, minimum-scale=1.0, user-scalable=yes, width=' + ww);
      }
    }
  }

  //ok, i need to update viewport scale if screen dimentions changed
  window.addEventListener('resize', function(){
    apply_viewport();
  });

  apply_viewport();

}());
</script>

Split Spark Dataframe string column into multiple columns

pyspark.sql.functions.split() is the right approach here - you simply need to flatten the nested ArrayType column into multiple top-level columns. In this case, where each array only contains 2 items, it's very easy. You simply use Column.getItem() to retrieve each part of the array as a column itself:

split_col = pyspark.sql.functions.split(df['my_str_col'], '-')
df = df.withColumn('NAME1', split_col.getItem(0))
df = df.withColumn('NAME2', split_col.getItem(1))

The result will be:

col1 | my_str_col | NAME1 | NAME2
-----+------------+-------+------
  18 |  856-yygrm |   856 | yygrm
 201 |  777-psgdg |   777 | psgdg

I am not sure how I would solve this in a general case where the nested arrays were not the same size from Row to Row.

How to auto-reload files in Node.js?

There was a recent thread about this subject on the node.js mailing list. The short answer is no, it's currently not possible auto-reload required files, but several people have developed patches that add this feature.

How do I set a conditional breakpoint in gdb, when char* x points to a string whose value equals "hello"?

You can use strcmp:

break x:20 if strcmp(y, "hello") == 0

20 is line number, x can be any filename and y can be any variable.

Find stored procedure by name

Option 1: In SSMS go to View > Object Explorer Details or press F7. Use the Search box. Finally in the displayed list right click and select Synchronize to find the object in the Object Explorer tree.

Object Explorer Details

Option 2: Install an Add-On like dbForge Search. Right click on the displayed list and select Find in Object Explorer.

enter image description here

How to create a new database after initally installing oracle database 11g Express Edition?

If you wish to create a new schema in XE, you need to create an USER and assign its privileges. Follow these steps:

  • Open the SQL*Plus Command-line
SQL> connect sys as sysdba
  • Enter the password
SQL> CREATE USER myschema IDENTIFIED BY Hga&dshja;
SQL> ALTER USER myschema QUOTA unlimited ON SYSTEM;
SQL> GRANT CREATE SESSION, CONNECT, RESOURCE, DBA TO myschema;
SQL> GRANT ALL PRIVILEGES TO myschema;

Now you can connect via Oracle SQL Developer and create your tables.

Find multiple files and rename them in Linux

If you just want to rename and don't mind using an external tool, then you can use rnm. The command would be:

#on current folder
rnm -dp -1 -fo -ssf '_dbg' -rs '/_dbg//' *

-dp -1 will make it recursive to all subdirectories.

-fo implies file only mode.

-ssf '_dbg' searches for files with _dbg in the filename.

-rs '/_dbg//' replaces _dbg with empty string.

You can run the above command with the path of the CURRENT_FOLDER too:

rnm -dp -1 -fo -ssf '_dbg' -rs '/_dbg//' /path/to/the/directory

The builds tools for v120 (Platform Toolset = 'v120') cannot be found

To add up to Louis answer:

Alternatively you can use the attribute ToolVersion="12.0" if you are using Visual Studio 2013 instead of using the ToolPath Attribute. Details visit http://msdn.microsoft.com/en-us/library/dd647548.aspx

So you are not forced to use absolute path.

How do I set up NSZombieEnabled in Xcode 4?

I find this alternative more convenient:

  1. Click the "Run Button Dropdown"
  2. From the list choose Profile
  3. The program "Instruments" should open where you can also choose Zombies
  4. Now you can interact with your app and try to cause the error
  5. As soon as the error happens you should get a hint on when your object was released and therefore deallocated.

Zombies

As soon as a zombie is detected you then get a neat "Zombie Stack" that shows you when the object in question was allocated and where it was retained or released:

Event Type    RefCt     Responsible Caller
Malloc            1     -[MyViewController loadData:]
Retain            2     -[MyDataManager initWithBaseURL:]
Release           1     -[MyDataManager initWithBaseURL:]
Release           0     -[MyViewController loadData:]
Zombie           -1     -[MyService prepareURLReuqest]

Advantages compared to using the diagnostic tab of the Xcode Schemes:

  1. If you forget to uncheck the option in the diagnostic tab there no objects will be released from memory.

  2. You get a more detailed stack that shows you in what methods your corrupt object was allocated / released or retained.

How to get "GET" request parameters in JavaScript?

If you already use jquery there is a jquery plugin that handles this:

http://plugins.jquery.com/project/query-object

How to do a case sensitive search in WHERE clause (I'm using SQL Server)?

In MySQL if You don't want to change the collation and want to perform case sensitive search then just use binary keyword like this:

SELECT * FROM table_name WHERE binary username=@search_parameter and binary password=@search_parameter

Jquery button click() function is not working

After making the id unique across the document ,You have to use event delegation

$("#container").on("click", "buttonid", function () {
  alert("Hi");
});

How to set environment via `ng serve` in Angular 6

You can try: ng serve --configuration=dev/prod

To build use: ng build --prod --configuration=dev

Hope you are using a different kind of environment.

How to format column to number format in Excel sheet?

Sorry to bump an old question but the answer is to count the character length of the cell and not its value.

CellCount = Cells(Row, 10).Value
If Len(CellCount) <= "13" Then
'do something
End If

hope that helps. Cheers

Changing file permission in Python

All the current answers clobber the non-writing permissions: they make the file readable-but-not-executable for everybody. Granted, this is because the initial question asked for 444 permissions -- but we can do better!

Here's a solution that leaves all the individual "read" and "execute" bits untouched. I wrote verbose code to make it easy to understand; you can make it more terse if you like.

import os
import stat

def remove_write_permissions(path):
    """Remove write permissions from this path, while keeping all other permissions intact.

    Params:
        path:  The path whose permissions to alter.
    """
    NO_USER_WRITING = ~stat.S_IWUSR
    NO_GROUP_WRITING = ~stat.S_IWGRP
    NO_OTHER_WRITING = ~stat.S_IWOTH
    NO_WRITING = NO_USER_WRITING & NO_GROUP_WRITING & NO_OTHER_WRITING

    current_permissions = stat.S_IMODE(os.lstat(path).st_mode)
    os.chmod(path, current_permissions & NO_WRITING)

Why does this work?

As John La Rooy pointed out,stat.S_IWUSR basically means "the bitmask for the user's write permissions". We want to set the corresponding permission bit to 0. To do that, we need the exact opposite bitmask (i.e., one with a 0 in that location, and 1's everywhere else). The ~ operator, which flips all the bits, gives us exactly that. If we apply this to any variable via the "bitwise and" operator (&), it will zero out the corresponding bit.

We need to repeat this logic with the "group" and "other" permission bits, too. Here we can save some time by just &'ing them all together (forming the NO_WRITING bit constant).

The last step is to get the current file's permissions, and actually perform the bitwise-and operation.

Hour from DateTime? in 24 hours format

Try this, if your input is string 
For example 

string input= "13:01";
string[] arry = input.Split(':');                  
string timeinput = arry[0] + arry[1];
private string Convert24To12HourInEnglish(string timeinput)

 {

DateTime startTime = new DateTime(2018, 1, 1, int.Parse(timeinput.Substring(0, 2)), 
int.Parse(timeinput.Substring(2, 2)), 0); 
return startTime.ToString("hh:mm tt");

}
out put: 01:01

Java substring: 'string index out of range'

if (itemdescription != null && itemdescription.length() > 0) {
    pstmt2.setString(3, itemdescription.substring(0, Math.min(itemdescription.length(), 38))); 
} else { 
    pstmt2.setString(3, "_"); 
}

How do I run a program with commandline arguments using GDB within a Bash script?

gdb -ex=r --args myprogram arg1 arg2

-ex=r is short for -ex=run and tells gdb to run your program immediately, rather than wait for you to type "run" at the prompt. Then --args says that everything that follows is the command and arguments, just as you'd normally type them at the commandline prompt.

Update Multiple Rows in Entity Framework from a list of ids

something like below

var idList=new int[]{1, 2, 3, 4};
using (var db=new SomeDatabaseContext())
{
    var friends= db.Friends.Where(f=>idList.Contains(f.ID)).ToList();
    friends.ForEach(a=>a.msgSentBy='1234');
    db.SaveChanges();
}

UPDATE:

you can update multiple fields as below

friends.ForEach(a =>
                      {
                         a.property1 = value1;
                         a.property2 = value2;
                      });

Get the second largest number in a list in linear time

You could always use sorted

>>> sorted(numbers)[-2]
74

Remove all whitespace in a string

try this.. instead of using re i think using split with strip is much better

def my_handle(self):
    sentence = ' hello  apple  '
    ' '.join(x.strip() for x in sentence.split())
#hello apple
    ''.join(x.strip() for x in sentence.split())
#helloapple

Writing files in Node.js

Here is the sample of how to read file csv from local and write csv file to local.

var csvjson = require('csvjson'),
    fs = require('fs'),
    mongodb = require('mongodb'),
    MongoClient = mongodb.MongoClient,
    mongoDSN = 'mongodb://localhost:27017/test',
    collection;

function uploadcsvModule(){
    var data = fs.readFileSync( '/home/limitless/Downloads/orders_sample.csv', { encoding : 'utf8'});
    var importOptions = {
        delimiter : ',', // optional 
        quote     : '"' // optional 
    },ExportOptions = {
        delimiter   : ",",
        wrap        : false
    }
    var myobj = csvjson.toSchemaObject(data, importOptions)
    var exportArr = [], importArr = [];
    myobj.forEach(d=>{
        if(d.orderId==undefined || d.orderId=='') {
            exportArr.push(d)
        } else {
            importArr.push(d)
        }
    })
    var csv = csvjson.toCSV(exportArr, ExportOptions);
    MongoClient.connect(mongoDSN, function(error, db) {
        collection = db.collection("orders")
        collection.insertMany(importArr, function(err,result){
            fs.writeFile('/home/limitless/Downloads/orders_sample1.csv', csv, { encoding : 'utf8'});
            db.close();
        });            
    })
}

uploadcsvModule()

How to empty a Heroku database

The complete answer is (for users with multi-db):

heroku pg:info - which outputs

=== HEROKU_POSTGRESQL_RED <-- this is DB
Plan Basic
Status available

heroku pg:reset HEROKU_POSTGRESQL_RED --confirm app_name

More information found in: https://devcenter.heroku.com/articles/heroku-postgresql

What's the best way to validate an XML file against an XSD file?

We build our project using ant, so we can use the schemavalidate task to check our config files:

<schemavalidate> 
    <fileset dir="${configdir}" includes="**/*.xml" />
</schemavalidate>

Now naughty config files will fail our build!

http://ant.apache.org/manual/Tasks/schemavalidate.html

Remove a CLASS for all child elements

You can also do like this :

  $("#table-filters li").parent().find('li').removeClass("active");

List all of the possible goals in Maven 2?

Lets make it very simple:

Maven Lifecycles: 1. Clean 2. Default (build) 3. Site

Maven Phases of the Default Lifecycle: 1. Validate 2. Compile 3. Test 4. Package 5. Verify 6. Install 7. Deploy

Note: Don't mix or get confused with maven goals with maven lifecycle.

See Maven Build Lifecycle Basics1

Can I call a function of a shell script from another shell script?

#vi function.sh

#!/bin/bash
f1() {
    echo "Hello $name"
}

f2() {
    echo "Enter your name: "
    read name
    f1
}
f2

#sh function.sh

Here function f2 will call function f1

Python sum() function with list parameter

In the last answer, you don't need to make a list from numbers; it is already a list:

numbers = [1, 2, 3]
numsum = sum(numbers)
print(numsum)

SQLAlchemy: What's the difference between flush() and commit()?

This does not strictly answer the original question but some people have mentioned that with session.autoflush = True you don't have to use session.flush()... And this is not always true.

If you want to use the id of a newly created object in the middle of a transaction, you must call session.flush().

# Given a model with at least this id
class AModel(Base):
   id = Column(Integer, primary_key=True)  # autoincrement by default on integer primary key

session.autoflush = True

a = AModel()
session.add(a)
a.id  # None
session.flush()
a.id  # autoincremented integer

This is because autoflush does NOT auto fill the id (although a query of the object will, which sometimes can cause confusion as in "why this works here but not there?" But snapshoe already covered this part).


One related aspect that seems pretty important to me and wasn't really mentioned:

Why would you not commit all the time? - The answer is atomicity.

A fancy word to say: an ensemble of operations have to all be executed successfully OR none of them will take effect.

For example, if you want to create/update/delete some object (A) and then create/update/delete another (B), but if (B) fails you want to revert (A). This means those 2 operations are atomic.

Therefore, if (B) needs a result of (A), you want to call flush after (A) and commit after (B).

Also, if session.autoflush is True, except for the case that I mentioned above or others in Jimbo's answer, you will not need to call flush manually.

Twitter Bootstrap 3, vertically center content

Option 1 is to use display:table-cell. You need to unfloat the Bootstrap col-* using float:none..

.center {
    display:table-cell;
    vertical-align:middle;
    float:none;
}

http://bootply.com/94394


Option 2 is display:flex to vertical align the row with flexbox:

.row.center {
   display: flex;
   align-items: center;
}

http://www.bootply.com/7rAuLpMCwr


Vertical centering is very different in Bootstrap 4. See this answer for Bootstrap 4 https://stackoverflow.com/a/41464397/171456

Creating a List of Lists in C#

I have been toying with this idea too, but I was trying to achieve a slightly different behavior. My idea was to make a list which inherits itself, thus creating a data structure that by nature allows you to embed lists within lists within lists within lists...infinitely!

Implementation

//InfiniteList<T> is a list of itself...
public class InfiniteList<T> : List<InfiniteList<T>>
{
    //This is necessary to allow your lists to store values (of type T).
    public T Value { set; get; }
}

T is a generic type parameter. It is there to ensure type safety in your class. When you create an instance of InfiniteList, you replace T with the type you want your list to be populated with, or in this instance, the type of the Value property.

Example

//The InfiniteList.Value property will be of type string
InfiniteList<string> list = new InfiniteList<string>();

A "working" example of this, where T is in itself, a List of type string!

//Create an instance of InfiniteList where T is List<string>
InfiniteList<List<string>> list = new InfiniteList<List<string>>();

//Add a new instance of InfiniteList<List<string>> to "list" instance.
list.Add(new InfiniteList<List<string>>());

//access the first element of "list". Access the Value property, and add a new string to it.
list[0].Value.Add("Hello World");

Principal Component Analysis (PCA) in Python

I posted my answer even though another answer has already been accepted; the accepted answer relies on a deprecated function; additionally, this deprecated function is based on Singular Value Decomposition (SVD), which (although perfectly valid) is the much more memory- and processor-intensive of the two general techniques for calculating PCA. This is particularly relevant here because of the size of the data array in the OP. Using covariance-based PCA, the array used in the computation flow is just 144 x 144, rather than 26424 x 144 (the dimensions of the original data array).

Here's a simple working implementation of PCA using the linalg module from SciPy. Because this implementation first calculates the covariance matrix, and then performs all subsequent calculations on this array, it uses far less memory than SVD-based PCA.

(the linalg module in NumPy can also be used with no change in the code below aside from the import statement, which would be from numpy import linalg as LA.)

The two key steps in this PCA implementation are:

  • calculating the covariance matrix; and

  • taking the eivenvectors & eigenvalues of this cov matrix

In the function below, the parameter dims_rescaled_data refers to the desired number of dimensions in the rescaled data matrix; this parameter has a default value of just two dimensions, but the code below isn't limited to two but it could be any value less than the column number of the original data array.


def PCA(data, dims_rescaled_data=2):
    """
    returns: data transformed in 2 dims/columns + regenerated original data
    pass in: data as 2D NumPy array
    """
    import numpy as NP
    from scipy import linalg as LA
    m, n = data.shape
    # mean center the data
    data -= data.mean(axis=0)
    # calculate the covariance matrix
    R = NP.cov(data, rowvar=False)
    # calculate eigenvectors & eigenvalues of the covariance matrix
    # use 'eigh' rather than 'eig' since R is symmetric, 
    # the performance gain is substantial
    evals, evecs = LA.eigh(R)
    # sort eigenvalue in decreasing order
    idx = NP.argsort(evals)[::-1]
    evecs = evecs[:,idx]
    # sort eigenvectors according to same index
    evals = evals[idx]
    # select the first n eigenvectors (n is desired dimension
    # of rescaled data array, or dims_rescaled_data)
    evecs = evecs[:, :dims_rescaled_data]
    # carry out the transformation on the data using eigenvectors
    # and return the re-scaled data, eigenvalues, and eigenvectors
    return NP.dot(evecs.T, data.T).T, evals, evecs

def test_PCA(data, dims_rescaled_data=2):
    '''
    test by attempting to recover original data array from
    the eigenvectors of its covariance matrix & comparing that
    'recovered' array with the original data
    '''
    _ , _ , eigenvectors = PCA(data, dim_rescaled_data=2)
    data_recovered = NP.dot(eigenvectors, m).T
    data_recovered += data_recovered.mean(axis=0)
    assert NP.allclose(data, data_recovered)


def plot_pca(data):
    from matplotlib import pyplot as MPL
    clr1 =  '#2026B2'
    fig = MPL.figure()
    ax1 = fig.add_subplot(111)
    data_resc, data_orig = PCA(data)
    ax1.plot(data_resc[:, 0], data_resc[:, 1], '.', mfc=clr1, mec=clr1)
    MPL.show()

>>> # iris, probably the most widely used reference data set in ML
>>> df = "~/iris.csv"
>>> data = NP.loadtxt(df, delimiter=',')
>>> # remove class labels
>>> data = data[:,:-1]
>>> plot_pca(data)

The plot below is a visual representation of this PCA function on the iris data. As you can see, a 2D transformation cleanly separates class I from class II and class III (but not class II from class III, which in fact requires another dimension).

enter image description here

Nested rows with bootstrap grid system?

Bootstrap Version 3.x

As always, read Bootstrap's great documentation:

3.x Docs: https://getbootstrap.com/docs/3.3/css/#grid-nesting

Make sure the parent level row is inside of a .container element. Whenever you'd like to nest rows, just open up a new .row inside of your column.

Here's a simple layout to work from:

<div class="container">
    <div class="row">
        <div class="col-xs-6">
            <div class="big-box">image</div>
        </div>
        <div class="col-xs-6">
            <div class="row">
                <div class="col-xs-6"><div class="mini-box">1</div></div>
                <div class="col-xs-6"><div class="mini-box">2</div></div>
                <div class="col-xs-6"><div class="mini-box">3</div></div>
                <div class="col-xs-6"><div class="mini-box">4</div></div>
            </div>
        </div>
    </div>
</div>

Bootstrap Version 4.0

4.0 Docs: http://getbootstrap.com/docs/4.0/layout/grid/#nesting

Here's an updated version for 4.0, but you should really read the entire docs section on the grid so you understand how to leverage this powerful feature

<div class="container">
  <div class="row">
    <div class="col big-box">
      image
    </div>

    <div class="col">
      <div class="row">
        <div class="col mini-box">1</div>
        <div class="col mini-box">2</div>
      </div>
      <div class="row">
        <div class="col mini-box">3</div>
        <div class="col mini-box">4</div>
      </div>
    </div>

  </div>
</div>

Demo in Fiddle jsFiddle 3.x | jsFiddle 4.0

Which will look like this (with a little bit of added styling):

screenshot

How large is a DWORD with 32- and 64-bit code?

Actually, on 32-bit computers a word is 32-bit, but the DWORD type is a leftover from the good old days of 16-bit.

In order to make it easier to port programs to the newer system, Microsoft has decided all the old types will not change size.

You can find the official list here: http://msdn.microsoft.com/en-us/library/aa383751(VS.85).aspx

All the platform-dependent types that changed with the transition from 32-bit to 64-bit end with _PTR (DWORD_PTR will be 32-bit on 32-bit Windows and 64-bit on 64-bit Windows).

Calculate the center point of multiple latitude/longitude coordinate pairs

If you want all points to be visible in the image, you'd want the extrema in latitude and longitude and make sure that your view includes those values with whatever border you want.

(From Alnitak's answer, how you calculate the extrema may be a little problematic, but if they're a few degrees on either side of the longitude that wraps around, then you'll call the shot and take the right range.)

If you don't want to distort whatever map that these points are on, then adjust the bounding box's aspect ratio so that it fits whatever pixels you've allocated to the view but still includes the extrema.

To keep the points centered at some arbitrary zooming level, calculate the center of the bounding box that "just fits" the points as above, and keep that point as the center point.

Server Document Root Path in PHP

$files = glob($_SERVER["DOCUMENT_ROOT"]."/myFolder/*");

The located assembly's manifest definition does not match the assembly reference

Had similar issue mentioned at this post "Any suggestions on how I figure out what is trying to reference this old version of this DLL file?"

Needed which assembly still refers old ODATA client 6.15.0 , the ildasm helped to narrow down for me (without base code access, only via deployed pkg at server).

Screen shot below for quick summary.

DeveloperPackge if don't have ildasm.exe https://www.microsoft.com/net/download/visual-studio-sdks

ildasm usage to resolve assembly mismatch issue

Getting an "ambiguous redirect" error

I just had this error in a bash script. The issue was an accidental \ at the end of the previous line that was giving an error.

How to remove a field completely from a MongoDB document?

you can also do this in aggregation by using project at 3.4

{$project: {"tags.words": 0} }

"git checkout <commit id>" is changing branch to "no branch"

If you checkout a commit sha directly, it puts you into a "detached head" state, which basically just means that the current sha that your working copy has checked out, doesn't have a branch pointing at it.

If you haven't made any commits yet, you can leave detached head state by simply checking out whichever branch you were on before checking out the commit sha:

git checkout <branch>

If you did make commits while you were in the detached head state, you can save your work by simply attaching a branch before or while you leave detached head state:

# Checkout a new branch at current detached head state:
git checkout -b newBranch

You can read more about detached head state at the official Linux Kernel Git docs for checkout.

How to validate an email address using a regular expression?

For a vivid demonstration, the following monster is pretty good but still does not correctly recognize all syntactically valid email addresses: it recognizes nested comments up to four levels deep.

This is a job for a parser, but even if an address is syntactically valid, it still may not be deliverable. Sometimes you have to resort to the hillbilly method of "Hey, y'all, watch ee-us!"

// derivative of work with the following copyright and license:
// Copyright (c) 2004 Casey West.  All rights reserved.
// This module is free software; you can redistribute it and/or
// modify it under the same terms as Perl itself.

// see http://search.cpan.org/~cwest/Email-Address-1.80/

private static string gibberish = @"
(?-xism:(?:(?-xism:(?-xism:(?-xism:(?-xism:(?-xism:(?-xism:\
s*\((?:\s*(?-xism:(?-xism:(?>[^()\\]+))|(?-xism:\\(?-xism:[^
\x0A\x0D]))|(?-xism:\s*\((?:\s*(?-xism:(?-xism:(?>[^()\\]+))
|(?-xism:\\(?-xism:[^\x0A\x0D]))|)+)*\s*\)\s*))+)*\s*\)\s*)+
|\s+)*[^\x00-\x1F\x7F()<>\[\]:;@\,.<DQ>\s]+(?-xism:(?-xism:\
s*\((?:\s*(?-xism:(?-xism:(?>[^()\\]+))|(?-xism:\\(?-xism:[^
\x0A\x0D]))|(?-xism:\s*\((?:\s*(?-xism:(?-xism:(?>[^()\\]+))
|(?-xism:\\(?-xism:[^\x0A\x0D]))|)+)*\s*\)\s*))+)*\s*\)\s*)+
|\s+)*)|(?-xism:(?-xism:(?-xism:\s*\((?:\s*(?-xism:(?-xism:(
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0D]))|)+)*\s*\)\s*))+)*\s*\)\s*)+|\s+)*<DQ>(?-xism:(?-xism:[
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s*)+|\s+)*))+)?(?-xism:(?-xism:(?-xism:\s*\((?:\s*(?-xism:(?
-xism:(?>[^()\\]+))|(?-xism:\\(?-xism:[^\x0A\x0D]))|(?-xism:
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sm:\\(?-xism:[^\x0A\x0D]))|)+)*\s*\)\s*))+)*\s*\)\s*)+|\s+)*
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ism:(?-xism:(?>[^()\\]+))|(?-xism:\\(?-xism:[^\x0A\x0D]))|)+
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-xism:[^\x0A\x0D]))|(?-xism:\s*\((?:\s*(?-xism:(?-xism:(?>[^
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)|(?-xism:\\(?-xism:[^\x0A\x0D]))|)+)*\s*\)\s*))+)*\s*\)\s*)
+|\s+)*)|(?-xism:(?-xism:(?-xism:\s*\((?:\s*(?-xism:(?-xism:
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(?:\s*(?-xism:(?-xism:(?>[^()\\]+))|(?-xism:\\(?-xism:[^\x0A
\x0D]))|)+)*\s*\)\s*))+)*\s*\)\s*)+|\s+)*\[(?:\s*(?-xism:(?-
xism:[^\[\]\\])|(?-xism:\\(?-xism:[^\x0A\x0D])))+)*\s*\](?-x
ism:(?-xism:\s*\((?:\s*(?-xism:(?-xism:(?>[^()\\]+))|(?-xism
:\\(?-xism:[^\x0A\x0D]))|(?-xism:\s*\((?:\s*(?-xism:(?-xism:
(?>[^()\\]+))|(?-xism:\\(?-xism:[^\x0A\x0D]))|)+)*\s*\)\s*))
+)*\s*\)\s*)+|\s+)*))))(?-xism:\s*\((?:\s*(?-xism:(?-xism:(?
>[^()\\]+))|(?-xism:\\(?-xism:[^\x0A\x0D]))|(?-xism:\s*\((?:
\s*(?-xism:(?-xism:(?>[^()\\]+))|(?-xism:\\(?-xism:[^\x0A\x0
D]))|)+)*\s*\)\s*))+)*\s*\)\s*)*)"
  .Replace("<DQ>", "\"")
  .Replace("\t", "")
  .Replace(" ", "")
  .Replace("\r", "")
  .Replace("\n", "");

private static Regex mailbox =
  new Regex(gibberish, RegexOptions.ExplicitCapture); 

SQL ON DELETE CASCADE, Which Way Does the Deletion Occur?

Cascade will work when you delete something on table Courses. Any record on table BookCourses that has reference to table Courses will be deleted automatically.

But when you try to delete on table BookCourses only the table itself is affected and not on the Courses

follow-up question: why do you have CourseID on table Category?

Maybe you should restructure your schema into this,

CREATE TABLE Categories 
(
  Code CHAR(4) NOT NULL PRIMARY KEY,
  CategoryName VARCHAR(63) NOT NULL UNIQUE
);

CREATE TABLE Courses 
(
  CourseID INT NOT NULL PRIMARY KEY,
  BookID INT NOT NULL,
  CatCode CHAR(4) NOT NULL,
  CourseNum CHAR(3) NOT NULL,
  CourseSec CHAR(1) NOT NULL,
);

ALTER TABLE Courses
ADD FOREIGN KEY (CatCode)
REFERENCES Categories(Code)
ON DELETE CASCADE;

How to send a POST request with BODY in swift

I've slightly edited SwiftDeveloper's answer, because it wasn't working for me. I added Alamofire validation as well.

let body: NSMutableDictionary? = [
    "name": "\(nameLabel.text!)",
    "phone": "\(phoneLabel.text!))"]

let url = NSURL(string: "http://server.com" as String)
var request = URLRequest(url: url! as URL)
request.httpMethod = "POST"
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
let data = try! JSONSerialization.data(withJSONObject: body!, options: JSONSerialization.WritingOptions.prettyPrinted)

let json = NSString(data: data, encoding: String.Encoding.utf8.rawValue)
if let json = json {
    print(json)
}
request.httpBody = json!.data(using: String.Encoding.utf8.rawValue)
let alamoRequest = Alamofire.request(request as URLRequestConvertible)
alamoRequest.validate(statusCode: 200..<300)
alamoRequest.responseString { response in

    switch response.result {
        case .success:
            ...
        case .failure(let error):
            ...
    }
}

How to get the hours difference between two date objects?

The simplest way would be to directly subtract the date objects from one another.

For example:

var hours = Math.abs(date1 - date2) / 36e5;

The subtraction returns the difference between the two dates in milliseconds. 36e5 is the scientific notation for 60*60*1000, dividing by which converts the milliseconds difference into hours.

Retrieve CPU usage and memory usage of a single process on Linux?

ps aux|awk  '{print $2,$3,$4}'|grep PID

where the first column is the PID,second column CPU usage ,third column memory usage.

Can I use wget to check , but not download

If you are in a directory where only root have access to write in system. Then you can directly use wget www.example.com/wget-test using a standard user account. So it will hit the url but because of having no write permission file won't be saved.. This method is working fine for me as i am using this method for a cronjob. Thanks.

sthx

Generating combinations in c++

A simple way using std::next_permutation:

#include <iostream>
#include <algorithm>
#include <vector>

int main() {
    int n, r;
    std::cin >> n;
    std::cin >> r;

    std::vector<bool> v(n);
    std::fill(v.end() - r, v.end(), true);

    do {
        for (int i = 0; i < n; ++i) {
            if (v[i]) {
                std::cout << (i + 1) << " ";
            }
        }
        std::cout << "\n";
    } while (std::next_permutation(v.begin(), v.end()));
    return 0;
}

or a slight variation that outputs the results in an easier to follow order:

#include <iostream>
#include <algorithm>
#include <vector>

int main() {
   int n, r;
   std::cin >> n;
   std::cin >> r;

   std::vector<bool> v(n);
   std::fill(v.begin(), v.begin() + r, true);

   do {
       for (int i = 0; i < n; ++i) {
           if (v[i]) {
               std::cout << (i + 1) << " ";
           }
       }
       std::cout << "\n";
   } while (std::prev_permutation(v.begin(), v.end()));
   return 0;
}

A bit of explanation:

It works by creating a "selection array" (v), where we place r selectors, then we create all permutations of these selectors, and print the corresponding set member if it is selected in in the current permutation of v.


You can implement it if you note that for each level r you select a number from 1 to n.

In C++, we need to 'manually' keep the state between calls that produces results (a combination): so, we build a class that on construction initialize the state, and has a member that on each call returns the combination while there are solutions: for instance

#include <iostream>
#include <iterator>
#include <vector>
#include <cstdlib>

using namespace std;

struct combinations
{
    typedef vector<int> combination_t;

    // initialize status
   combinations(int N, int R) :
       completed(N < 1 || R > N),
       generated(0),
       N(N), R(R)
   {
       for (int c = 1; c <= R; ++c)
           curr.push_back(c);
   }

   // true while there are more solutions
   bool completed;

   // count how many generated
   int generated;

   // get current and compute next combination
   combination_t next()
   {
       combination_t ret = curr;

       // find what to increment
       completed = true;
       for (int i = R - 1; i >= 0; --i)
           if (curr[i] < N - R + i + 1)
           {
               int j = curr[i] + 1;
               while (i <= R-1)
                   curr[i++] = j++;
               completed = false;
               ++generated;
               break;
           }

       return ret;
   }

private:

   int N, R;
   combination_t curr;
};

int main(int argc, char **argv)
{
    int N = argc >= 2 ? atoi(argv[1]) : 5;
    int R = argc >= 3 ? atoi(argv[2]) : 2;
    combinations cs(N, R);
    while (!cs.completed)
    {
        combinations::combination_t c = cs.next();
        copy(c.begin(), c.end(), ostream_iterator<int>(cout, ","));
        cout << endl;
    }
    return cs.generated;
}

test output:

1,2,
1,3,
1,4,
1,5,
2,3,
2,4,
2,5,
3,4,
3,5,
4,5,

Inserting into Oracle and retrieving the generated sequence ID

You can do this with a single statement - assuming you are calling it from a JDBC-like connector with in/out parameters functionality:

insert into batch(batchid, batchname) 
values (batch_seq.nextval, 'new batch')
returning batchid into :l_batchid;

or, as a pl-sql script:

variable l_batchid number;

insert into batch(batchid, batchname) 
values (batch_seq.nextval, 'new batch')
returning batchid into :l_batchid;

select :l_batchid from dual;

Making an image act like a button

It sounds like you want an image button:

<input type="image" src="logg.png" name="saveForm" class="btTxt submit" id="saveForm" />

Alternatively, you can use CSS to make the existing submit button use your image as its background.

In any case, you don't want a separate <img /> element on the page.

Mysql select distinct

You can use group by instead of distinct. Because when you use distinct, you'll get struggle to select all values from table. Unlike when you use group by, you can get distinct values and also all fields in table.

Check whether values in one data frame column exist in a second data frame

Use %in% as follows

A$C %in% B$C

Which will tell you which values of column C of A are in B.

What is returned is a logical vector. In the specific case of your example, you get:

A$C %in% B$C
# [1]  TRUE FALSE  TRUE  TRUE

Which you can use as an index to the rows of A or as an index to A$C to get the actual values:

# as a row index
A[A$C %in% B$C,  ]  # note the comma to indicate we are indexing rows

# as an index to A$C
A$C[A$C %in% B$C]
[1] 1 3 4  # returns all values of A$C that are in B$C

We can negate it too:

A$C[!A$C %in% B$C]
[1] 2   # returns all values of A$C that are NOT in B$C



If you want to know if a specific value is in B$C, use the same function:

  2 %in% B$C   # "is the value 2 in B$C ?"  
  # FALSE

  A$C[2] %in% B$C  # "is the 2nd element of A$C in B$C ?"  
  # FALSE

Mark error in form using Bootstrap

Generally showing the error near where the error occurs is best. i.e. if someone has an error with entering their email, you highlight the email input box.

This article has a couple good examples. http://uxdesign.smashingmagazine.com/2011/05/27/getting-started-with-defensive-web-design/

Also twitter bootstrap has some nice styling that helps with that (scroll down to the Validation states section) http://twitter.github.com/bootstrap/base-css.html#forms

Highlighting each input box is a bit more complicated, so the easy way would be to just put an bootstrap alert at the top with details of what the user did wrong. http://twitter.github.com/bootstrap/components.html#alerts

Detect Safari using jQuery

This will determine whether the browser is Safari or not.

if(navigator.userAgent.indexOf('Safari') !=-1 && navigator.userAgent.indexOf('Chrome') == -1)
{
    alert(its safari);
}else {
    alert('its not safari');
}

Show datalist labels but submit the actual value

I realize this may be a bit late, but I stumbled upon this and was wondering how to handle situations with multiple identical values, but different keys (as per bigbearzhu's comment).

So I modified Stephan Muller's answer slightly:

A datalist with non-unique values:

<input list="answers" name="answer" id="answerInput">
<datalist id="answers">
  <option value="42">The answer</option>
  <option value="43">The answer</option>
  <option value="44">Another Answer</option>
</datalist>
<input type="hidden" name="answer" id="answerInput-hidden">

When the user selects an option, the browser replaces input.value with the value of the datalist option instead of the innerText.

The following code then checks for an option with that value, pushes that into the hidden field and replaces the input.value with the innerText.

document.querySelector('#answerInput').addEventListener('input', function(e) {
    var input = e.target,   
        list = input.getAttribute('list'),
        options = document.querySelectorAll('#' + list + ' option[value="'+input.value+'"]'),
        hiddenInput = document.getElementById(input.getAttribute('id') + '-hidden');

    if (options.length > 0) {
      hiddenInput.value = input.value;
      input.value = options[0].innerText;
      }

});

As a consequence the user sees whatever the option's innerText says, but the unique id from option.value is available upon form submit. Demo jsFiddle

Unsetting array values in a foreach loop

Sorry for the late response, I recently had the same problem with PHP and found out that when working with arrays that do not use $key => $value structure, when using the foreach loop you actual copy the value of the position on the loop variable, in this case $image. Try using this code and it will fix your problem.

for ($i=0; $i < count($images[1]); $i++)
{

    if($images[1][$i] == 'http://i27.tinypic.com/29yk345.gif' ||

    $images[1][$i] == 'http://img3.abload.de/img/10nx2340fhco.gif' ||

    $images[1][$i] == 'http://i42.tinypic.com/9pp2456x.gif')

    {

        unset($images[1][$i]);

    }

}

var_dump($images);die();

Convert Json string to Json object in Swift 4

I used below code and it's working fine for me. :

let jsonText = "{\"userName\":\"Bhavsang\"}"
var dictonary:NSDictionary?
    
if let data = jsonText.dataUsingEncoding(NSUTF8StringEncoding) {
        
     do {
            dictonary =  try NSJSONSerialization.JSONObjectWithData(data, options: [.allowFragments]) as? [String:AnyObject]
        
            if let myDictionary = dictonary
              {
                  print(" User name is: \(myDictionary["userName"]!)")
              }
            } catch let error as NSError {
            
            print(error)
         }
}

how to automatically scroll down a html page?

here is the example using Pure JavaScript

_x000D_
_x000D_
function scrollpage() {  _x000D_
 function f() _x000D_
 {_x000D_
  window.scrollTo(0,i);_x000D_
  if(status==0) {_x000D_
      i=i+40;_x000D_
   if(i>=Height){ status=1; } _x000D_
  } else {_x000D_
   i=i-40;_x000D_
   if(i<=1){ status=0; }  // if you don't want continue scroll then remove this line_x000D_
  }_x000D_
 setTimeout( f, 0.01 );_x000D_
 }f();_x000D_
}_x000D_
var Height=document.documentElement.scrollHeight;_x000D_
var i=1,j=Height,status=0;_x000D_
scrollpage();_x000D_
</script>
_x000D_
<style type="text/css">_x000D_
_x000D_
 #top { border: 1px solid black;  height: 20000px; }_x000D_
 #bottom { border: 1px solid red; }_x000D_
_x000D_
</style>
_x000D_
<div id="top">top</div>_x000D_
<div id="bottom">bottom</div>
_x000D_
_x000D_
_x000D_

sed edit file in place

Versions of sed that support the -i option for editing a file in place write to a temporary file and then rename the file.

Alternatively, you can just use ed. For example, to change all occurrences of foo to bar in the file file.txt, you can do:

echo ',s/foo/bar/g; w' | tr \; '\012' | ed -s file.txt

Syntax is similar to sed, but certainly not exactly the same.

Even if you don't have a -i supporting sed, you can easily write a script to do the work for you. Instead of sed -i 's/foo/bar/g' file, you could do inline file sed 's/foo/bar/g'. Such a script is trivial to write. For example:

#!/bin/sh
IN=$1
shift
trap 'rm -f "$tmp"' 0
tmp=$( mktemp )
<"$IN" "$@" >"$tmp" && cat "$tmp" > "$IN"  # preserve hard links

should be adequate for most uses.

How to change the style of alert box?

I know this is an older post but I was looking for something similar this morning. I feel that my solution was much simpler after looking over some of the other solutions. One thing is that I use font awesome in the anchor tag.

I wanted to display an event on my calendar when the user clicked the event. So I coded a separate <div> tag like so:

<div id="eventContent" class="eventContent" style="display: none; border: 1px solid #005eb8; position: absolute; background: #fcf8e3; width: 30%; opacity: 1.0; padding: 4px; color: #005eb8; z-index: 2000; line-height: 1.1em;">
        <a style="float: right;"><i class="fa fa-times closeEvent" aria-hidden="true"></i></a><br />
        Event: <span id="eventTitle" class="eventTitle"></span><br />
        Start: <span id="startTime" class="startTime"></span><br />
        End: <span id="endTime" class="endTime"></span><br /><br />
</div>

I find it easier to use class names in my jquery since I am using asp.net.

Below is the jquery for my fullcalendar app.

<script>
    $(document).ready(function() {
        $('#calendar').fullCalendar({
            googleCalendarApiKey: 'APIkey',
            header: {
                left: 'prev,next today',
                center: 'title',
                right: 'month,agendaWeek,agendaDay'
            },
            events: {
                googleCalendarId: '@group.calendar.google.com'
            },
            eventClick: function (calEvent, jsEvent, view) {
                var stime = calEvent.start.format('MM/DD/YYYY, h:mm a');
                var etime = calEvent.end.format('MM/DD/YYYY, h:mm a');
                var eTitle = calEvent.title;
                var xpos = jsEvent.pageX;
                var ypos = jsEvent.pageY;
                $(".eventTitle").html(eTitle);
                $(".startTime").html(stime);
                $(".endTime").html(etime);
                $(".eventContent").css('display', 'block');
                $(".eventContent").css('left', '25%');
                $(".eventContent").css('top', '30%');
                return false;
            }
        });
        $(".eventContent").click(function() {
            $(".eventContent").css('display', 'none');
        });
    });
</script>

You must have your own google calendar id and api keys.

I hope this helps when you need a simple popup display.

Error starting Tomcat from NetBeans - '127.0.0.1*' is not recognized as an internal or external command

After following the steps from @Johnride, I still got the same error.

This fixed the problem:

Tools-> Options-> Select no proxy

source: https://www.youtube.com/watch?v=uI1j-8F8eN4

CSS display:inline property with list-style-image: property on <li> tags

I had similar problem, i solve using css ":before".. the code looks likes this:

.widgets li:before{
    content:"• ";
}

Node.js quick file server (static files over HTTP)

Below worked for me:

Create a file app.js with below contents:

// app.js

var fs = require('fs'),
    http = require('http');

http.createServer(function (req, res) {
  fs.readFile(__dirname + req.url, function (err,data) {
    if (err) {
      res.writeHead(404);
      res.end(JSON.stringify(err));
      return;
    }
    res.writeHead(200);
    res.end(data);
  });
}).listen(8080);

Create a file index.html with below contents:

Hi

Start a command line:

cmd

Run below in cmd:

node app.js

Goto below URL, in chrome:

http://localhost:8080/index.html

That's all. Hope that helps.

Source: https://nodejs.org/en/knowledge/HTTP/servers/how-to-serve-static-files/

Entity Framework and SQL Server View

Due to the above mentioned problems, I prefer table value functions.

If you have this:

CREATE VIEW [dbo].[MyView] AS SELECT A, B FROM dbo.Something

create this:

CREATE FUNCTION MyFunction() RETURNS TABLE AS RETURN (SELECT * FROM [dbo].[MyView])

Then you simply import the function rather than the view.

What is the best way to dump entire objects to a log in C#?

Based on @engineforce answer, I made this class that I'm using in a PCL project of a Xamarin Solution:

/// <summary>
/// Based on: https://stackoverflow.com/a/42264037/6155481
/// </summary>
public class ObjectDumper
{
    public static string Dump(object obj)
    {
        return new ObjectDumper().DumpObject(obj);
    }

    StringBuilder _dumpBuilder = new StringBuilder();

    string DumpObject(object obj)
    {
        DumpObject(obj, 0);
        return _dumpBuilder.ToString();
    }

    void DumpObject(object obj, int nestingLevel)
    {
        var nestingSpaces = "".PadLeft(nestingLevel * 4);

        if (obj == null)
        {
            _dumpBuilder.AppendFormat("{0}null\n", nestingSpaces);
        }
        else if (obj is string || obj.GetType().GetTypeInfo().IsPrimitive || obj.GetType().GetTypeInfo().IsEnum)
        {
            _dumpBuilder.AppendFormat("{0}{1}\n", nestingSpaces, obj);
        }
        else if (ImplementsDictionary(obj.GetType()))
        {
            using (var e = ((dynamic)obj).GetEnumerator())
            {
                var enumerator = (IEnumerator)e;
                while (enumerator.MoveNext())
                {
                    dynamic p = enumerator.Current;

                    var key = p.Key;
                    var value = p.Value;
                    _dumpBuilder.AppendFormat("{0}{1} ({2})\n", nestingSpaces, key, value != null ? value.GetType().ToString() : "<null>");
                    DumpObject(value, nestingLevel + 1);
                }
            }
        }
        else if (obj is IEnumerable)
        {
            foreach (dynamic p in obj as IEnumerable)
            {
                DumpObject(p, nestingLevel);
            }
        }
        else
        {
            foreach (PropertyInfo descriptor in obj.GetType().GetRuntimeProperties())
            {
                string name = descriptor.Name;
                object value = descriptor.GetValue(obj);

                _dumpBuilder.AppendFormat("{0}{1} ({2})\n", nestingSpaces, name, value != null ? value.GetType().ToString() : "<null>");

                // TODO: Prevent recursion due to circular reference
                if (name == "Self" && HasBaseType(obj.GetType(), "NSObject"))
                {
                    // In ObjC I need to break the recursion when I find the Self property
                    // otherwise it will be an infinite recursion
                    Console.WriteLine($"Found Self! {obj.GetType()}");
                }
                else
                {
                    DumpObject(value, nestingLevel + 1);
                }
            }
        }
    }

    bool HasBaseType(Type type, string baseTypeName)
    {
        if (type == null) return false;

        string typeName = type.Name;

        if (baseTypeName == typeName) return true;

        return HasBaseType(type.GetTypeInfo().BaseType, baseTypeName);
    }

    bool ImplementsDictionary(Type t)
    {
        return t is IDictionary;
    }
}

How to create a Multidimensional ArrayList in Java?

You can also do something like this ...

  • First create and Initialize the matrix or multidimensional arraylist

    ArrayList<ArrayList<Integer>> list; MultidimentionalArrayList(int x,int y) { list = new ArrayList<>(); for(int i=0;i<=x;i++) { ArrayList<Integer> temp = new ArrayList<>(Collections.nCopies(y+1,0)); list.add(temp); } }

    • Add element at specific position void add(int row,int column,int val) { list.get(row).set(column,val); // list[row][column]=val }

    This static matrix can be change into dynamic if check that row and column are out of bound. just insert extra temp arraylist for row

    • remove element

    int remove(int row, int column) { return list.get(row).remove(column);// del list[row][column] }

"Data too long for column" - why?

I had a similar problem when migrating an old database to a new version.

Switch the MySQL mode to not use STRICT.

SET @@global.sql_mode= 'NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION';

Error Code: 1406. Data too long for column - MySQL

What's the point of 'meta viewport user-scalable=no' in the Google Maps API

On many devices (such as the iPhone), it prevents the user from using the browser's zoom. If you have a map and the browser does the zooming, then the user will see a big ol' pixelated image with huge pixelated labels. The idea is that the user should use the zooming provided by Google Maps. Not sure about any interaction with your plugin, but that's what it's there for.

More recently, as @ehfeng notes in his answer, Chrome for Android (and perhaps others) have taken advantage of the fact that there's no native browser zooming on pages with a viewport tag set like that. This allows them to get rid of the dreaded 300ms delay on touch events that the browser takes to wait and see if your single touch will end up being a double touch. (Think "single click" and "double click".) However, when this question was originally asked (in 2011), this wasn't true in any mobile browser. It's just added awesomeness that fortuitously arose more recently.

How to append strings using sprintf?

I think you are looking for fmemopen(3):

#include <assert.h>
#include <stdio.h>

int main(void)
{
    char buf[128] = { 0 };
    FILE *fp = fmemopen(buf, sizeof(buf), "w");

    assert(fp);

    fprintf(fp, "Hello World!\n");
    fprintf(fp, "%s also work, of course.\n", "Format specifiers");
    fclose(fp);

    puts(buf);
    return 0;
}

If dynamic storage is more suitable for you use-case you could follow Liam's excellent suggestion about using open_memstream(3):

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    char *buf;
    size_t size;
    FILE *fp = open_memstream(&buf, &size);

    assert(fp);

    fprintf(fp, "Hello World!\n");
    fprintf(fp, "%s also work, of course.\n", "Format specifiers");
    fclose(fp);

    puts(buf);
    free(buf);
    return 0;
}

limit text length in php and provide 'Read more' link

This is what I use:

// strip tags to avoid breaking any html
$string = strip_tags($string);
if (strlen($string) > 500) {

    // truncate string
    $stringCut = substr($string, 0, 500);
    $endPoint = strrpos($stringCut, ' ');

    //if the string doesn't contain any space then it will cut without word basis.
    $string = $endPoint? substr($stringCut, 0, $endPoint) : substr($stringCut, 0);
    $string .= '... <a href="/this/story">Read More</a>';
}
echo $string;

You can tweak it further but it gets the job done in production.

ngOnInit not being called when Injectable class is Instantiated

Lifecycle hooks, like OnInit() work with Directives and Components. They do not work with other types, like a service in your case. From docs:

A Component has a lifecycle managed by Angular itself. Angular creates it, renders it, creates and renders its children, checks it when its data-bound properties change and destroy it before removing it from the DOM.

Directive and component instances have a lifecycle as Angular creates, updates, and destroys them.

Syntax for a single-line Bash infinite while loop

You can also make use of until command:

until ((0)); do foo; sleep 2; done

Note that in contrast to while, until would execute the commands inside the loop as long as the test condition has an exit status which is not zero.


Using a while loop:

while read i; do foo; sleep 2; done < /dev/urandom

Using a for loop:

for ((;;)); do foo; sleep 2; done

Another way using until:

until [ ]; do foo; sleep 2; done

How to fill Dataset with multiple tables?

Filling a DataSet with multiple tables can be done by sending multiple requests to the database, or in a faster way: Multiple SELECT statements can be sent to the database server in a single request. The problem here is that the tables generated from the queries have automatic names Table and Table1. However, the generated table names can be mapped to names that should be used in the DataSet.

SqlDataAdapter adapter = new SqlDataAdapter(
      "SELECT * FROM Customers; SELECT * FROM Orders", connection);
adapter.TableMappings.Add("Table", "Customer");
adapter.TableMappings.Add("Table1", "Order");

adapter.Fill(ds);

CSS Margin: 0 is not setting to 0

h1 {
margin-top:0;
padding-top: 0;}

It' s just a misunderstanding with h1 tag. You have to set h1 tag margin-top and padding-top to 0 (zero).

sprintf like functionality in Python

To insert into a very long string it is nice to use names for the different arguments, instead of hoping they are in the right positions. This also makes it easier to replace multiple recurrences.

>>> 'Coordinates: {latitude}, {longitude}'.format(latitude='37.24N', longitude='-115.81W')
'Coordinates: 37.24N, -115.81W'

Taken from Format examples, where all the other Format-related answers are also shown.

Container is running beyond memory limits

I had a really similar issue using HIVE in EMR. None of the extant solutions worked for me -- ie, none of the mapreduce configurations worked for me; and neither did setting yarn.nodemanager.vmem-check-enabled to false.

However, what ended up working was setting tez.am.resource.memory.mb, for example:

hive -hiveconf tez.am.resource.memory.mb=4096

Another setting to consider tweaking is yarn.app.mapreduce.am.resource.mb

How do I add python3 kernel to jupyter (IPython)

For the current Python Launcher

If you have Py3 installed but default to py2

py -3 -m pip install ipykernel
py -3 -m ipykernel install --user

If you have Py2 installed but default to py3

py -2 -m pip install ipykernel
py -2 -m ipykernel install --user

Where's my JSON data in my incoming Django request?

Something like this. It's worked: Request data from client

registerData = {
{% for field in userFields%}
  {{ field.name }}: {{ field.name }},
{% endfor %}
}


var request = $.ajax({
   url: "{% url 'MainApp:rq-create-account-json' %}",
   method: "POST",
   async: false,
   contentType: "application/json; charset=utf-8",
   data: JSON.stringify(registerData),
   dataType: "json"
});

request.done(function (msg) {
   [alert(msg);]
   alert(msg.name);
});

request.fail(function (jqXHR, status) {
  alert(status);
});

Process request at the server

@csrf_exempt
def rq_create_account_json(request):
   if request.is_ajax():
       if request.method == 'POST':
           json_data = json.loads(request.body)
           print(json_data)
           return JsonResponse(json_data)
   return HttpResponse("Error")

How should I call 3 functions in order to execute them one after the other?

In Javascript, there are synchronous and asynchronous functions.

Synchronous Functions

Most functions in Javascript are synchronous. If you were to call several synchronous functions in a row

doSomething();
doSomethingElse();
doSomethingUsefulThisTime();

they will execute in order. doSomethingElse will not start until doSomething has completed. doSomethingUsefulThisTime, in turn, will not start until doSomethingElse has completed.

Asynchronous Functions

Asynchronous function, however, will not wait for each other. Let us look at the same code sample we had above, this time assuming that the functions are asynchronous

doSomething();
doSomethingElse();
doSomethingUsefulThisTime();

The functions will be initialized in order, but they will all execute roughly at the same time. You can't consistently predict which one will finish first: the one that happens to take the shortest amount of time to execute will finish first.

But sometimes, you want functions that are asynchronous to execute in order, and sometimes you want functions that are synchronous to execute asynchronously. Fortunately, this is possible with callbacks and timeouts, respectively.

Callbacks

Let's assume that we have three asynchronous functions that we want to execute in order, some_3secs_function, some_5secs_function, and some_8secs_function.

Since functions can be passed as arguments in Javascript, you can pass a function as a callback to execute after the function has completed.

If we create the functions like this

function some_3secs_function(value, callback){
  //do stuff
  callback();
}

then you can call then in order, like this:

some_3secs_function(some_value, function() {
  some_5secs_function(other_value, function() {
    some_8secs_function(third_value, function() {
      //All three functions have completed, in order.
    });
  });
});

Timeouts

In Javascript, you can tell a function to execute after a certain timeout (in milliseconds). This can, in effect, make synchronous functions behave asynchronously.

If we have three synchronous functions, we can execute them asynchronously using the setTimeout function.

setTimeout(doSomething, 10);
setTimeout(doSomethingElse, 10);
setTimeout(doSomethingUsefulThisTime, 10);

This is, however, a bit ugly and violates the DRY principle[wikipedia]. We could clean this up a bit by creating a function that accepts an array of functions and a timeout.

function executeAsynchronously(functions, timeout) {
  for(var i = 0; i < functions.length; i++) {
    setTimeout(functions[i], timeout);
  }
}

This can be called like so:

executeAsynchronously(
    [doSomething, doSomethingElse, doSomethingUsefulThisTime], 10);

In summary, if you have asynchronous functions that you want to execute syncronously, use callbacks, and if you have synchronous functions that you want to execute asynchronously, use timeouts.

SQL Server CASE .. WHEN .. IN statement

It might be easier to read when written out in longhand using the 'simple case' e.g.

CASE DeviceID 
   WHEN '7  ' THEN '01'
   WHEN '10 ' THEN '01'
   WHEN '62 ' THEN '01'
   WHEN '58 ' THEN '01'
   WHEN '60 ' THEN '01'
   WHEN '46 ' THEN '01'
   WHEN '48 ' THEN '01'
   WHEN '50 ' THEN '01'
   WHEN '137' THEN '01'
   WHEN '139' THEN '01'
   WHEN '142' THEN '01'
   WHEN '143' THEN '01'
   WHEN '164' THEN '01'
   WHEN '8  ' THEN '02'
   WHEN '9  ' THEN '02'
   WHEN '63 ' THEN '02'
   WHEN '59 ' THEN '02'
   WHEN '61 ' THEN '02'
   WHEN '47 ' THEN '02'
   WHEN '49 ' THEN '02'
   WHEN '51 ' THEN '02'
   WHEN '138' THEN '02'
   WHEN '140' THEN '02'
   WHEN '141' THEN '02'
   WHEN '144' THEN '02'
   WHEN '165' THEN '02'
   ELSE 'NA' 
END AS clocking

...which kind makes me thing that perhaps you could benefit from a lookup table to which you can JOIN to eliminate the CASE expression entirely.

What's the actual use of 'fail' in JUnit test case?

I've used it in the case where something may have gone awry in my @Before method.

public Object obj;

@Before
public void setUp() {
    // Do some set up
    obj = new Object();
}

@Test
public void testObjectManipulation() {
    if(obj == null) {
        fail("obj should not be null");
     }

    // Do some other valuable testing
}

How to call another controller Action From a controller in Mvc

Let the resolver automatically do that.

Inside A controller:

public class AController : ApiController
{
    private readonly BController _bController;

    public AController(
    BController bController)
    {
        _bController = bController;
    }

    public httpMethod{
    var result =  _bController.OtherMethodBController(parameters);
    ....
    }

}

How can I check for existence of element in std::vector, in one line?

int elem = 42;
std::vector<int> v;
v.push_back(elem);
if(std::find(v.begin(), v.end(), elem) != v.end())
{
  //elem exists in the vector
} 

Is there any way I can define a variable in LaTeX?

This works for me: \newcommand{\variablename}{the text}

For eg: \newcommand\m{100}

So when you type " \m\ is my mark " in the source code,

the pdf output displays as :

100 is my mark

How to do something before on submit?

You can use onclick to run some JavaScript or jQuery code before submitting the form like this:

<script type="text/javascript">
    beforeSubmit = function(){
        if (1 == 1){
            //your before submit logic
        }        
        $("#formid").submit();            
    }
</script>
<input type="button" value="Click" onclick="beforeSubmit();" />

Converting string from snake_case to CamelCase in Ruby

Source: http://rubydoc.info/gems/extlib/0.9.15/String#camel_case-instance_method

For learning purpose:

class String
  def camel_case
    return self if self !~ /_/ && self =~ /[A-Z]+.*/
    split('_').map{|e| e.capitalize}.join
  end
end

"foo_bar".camel_case          #=> "FooBar"

And for the lowerCase variant:

class String
  def camel_case_lower
    self.split('_').inject([]){ |buffer,e| buffer.push(buffer.empty? ? e : e.capitalize) }.join
  end
end

"foo_bar".camel_case_lower          #=> "fooBar"

Programmatically change the height and width of a UIImageView Xcode Swift

The accepted answer in Swift 3:

let screenSize: CGRect = UIScreen.main.bounds
image.frame = CGRect(x: 0, y: 0, width: 50, height: screenSize.height * 0.2)

Equivalent of Math.Min & Math.Max for Dates?

How about:

public static T Min<T>(params T[] values)
{
    if (values == null) throw new ArgumentNullException("values");
    var comparer = Comparer<T>.Default;
    switch(values.Length) {
        case 0: throw new ArgumentException();
        case 1: return values[0];
        case 2: return comparer.Compare(values[0],values[1]) < 0
               ? values[0] : values[1];
        default:
            T best = values[0];
            for (int i = 1; i < values.Length; i++)
            {
                if (comparer.Compare(values[i], best) < 0)
                {
                    best = values[i];
                }
            }
            return best;
    }        
}
// overload for the common "2" case...
public static T Min<T>(T x, T y)
{
    return Comparer<T>.Default.Compare(x, y) < 0 ? x : y;
}

Works with any type that supports IComparable<T> or IComparable.

Actually, with LINQ, another alternative is:

var min = new[] {x,y,z}.Min();

How do I properly clean up Excel interop objects?

My solution

[DllImport("user32.dll")]
static extern int GetWindowThreadProcessId(int hWnd, out int lpdwProcessId);

private void GenerateExcel()
{
    var excel = new Microsoft.Office.Interop.Excel.Application();
    int id;
    // Find the Excel Process Id (ath the end, you kill him
    GetWindowThreadProcessId(excel.Hwnd, out id);
    Process excelProcess = Process.GetProcessById(id);

try
{
    // Your code
}
finally
{
    excel.Quit();

    // Kill him !
    excelProcess.Kill();
}

OpenCV with Network Cameras

rtsp protocol did not work for me. mjpeg worked first try. I assume it is built into my camera (Dlink DCS 900).

Syntax found here: http://answers.opencv.org/question/133/how-do-i-access-an-ip-camera/

I did not need to compile OpenCV with ffmpg support.

Concatenating variables in Bash

Try doing this, there's no special character to concatenate in bash :

mystring="${arg1}12${arg2}endoffile"

explanations

If you don't put brackets, you will ask to concatenate $arg112 + $argendoffile (I guess that's not what you asked) like in the following example :

mystring="$arg112$arg2endoffile"

The brackets are delimiters for the variables when needed. When not needed, you can use it or not.

another solution

(less portable : require bash > 3.1)

$ arg1=foo
$ arg2=bar
$ mystring="$arg1"
$ mystring+="12"
$ mystring+="$arg2"
$ mystring+="endoffile"
$ echo "$mystring"
foo12barendoffile

See http://mywiki.wooledge.org/BashFAQ/013

Installing ADB on macOS

Option 3 - Using MacPorts

Analoguously to the two options (homebrew / manual) posted by @brismuth, here's the MacPorts way:

  1. Install the Android SDK:

    sudo port install android
    
  2. Run the SDK manager:

    sh /opt/local/share/java/android-sdk-macosx/tools/android
    
  3. As @brismuth suggested, uncheck everything but Android SDK Platform-tools (optional)

  4. Install the packages, accepting licenses. Close the SDK Manager.

  5. Add platform-tools to your path; in MacPorts, they're in /opt/local/share/java/android-sdk-macosx/platform-tools. E.g., for bash:

    echo 'export PATH=$PATH:/opt/local/share/java/android-sdk-macosx/platform-tools' >> ~/.bash_profile
    
  6. Refresh your bash profile (or restart your terminal/shell):

    source ~/.bash_profile
    
  7. Start using adb:

    adb devices
    

Get row-index values of Pandas DataFrame as list?

To get the index values as a list/list of tuples for Index/MultiIndex do:

df.index.values.tolist()  # an ndarray method, you probably shouldn't depend on this

or

list(df.index.values)  # this will always work in pandas

Oracle: Import CSV file

Somebody asked me to post a link to the framework! that I presented at Open World 2012. This is the full blog post that demonstrates how to architect a solution with external tables.

Python: Importing urllib.quote

If you need to handle both Python 2.x and 3.x you can catch the exception and load the alternative.

try:
    from urllib import quote  # Python 2.X
except ImportError:
    from urllib.parse import quote  # Python 3+

You could also use the python compatibility wrapper six to handle this.

from six.moves.urllib.parse import quote

XPath: Get parent node from child node

This works in my case. I hope you can extract meaning out of it.

//div[text()='building1' and @class='wrap']/ancestor::tr/td/div/div[@class='x-grid-row-checker']

Can't bind to 'ngForOf' since it isn't a known property of 'tr' (final release)

In my case, the issue was that my teammate mentioned *ngfor in templates instead of *ngFor. Strange that there is no correct error to handle this issue (In Angular 4).

Use awk to find average of a column

Your specific error is with line 11:

awk 'BEGIN{sum+=$2}'

This is a line where awk is invoked, and its BEGIN block is specified - but you are already within a awk script, so you do not need to specify awk. Also you want to run sum+=$2 on each line of input, so you do not want it within a BEGIN block. Hence the line should simply read:

sum+=$2

You also do not need the lines:

x=sum
read name

the first just creates a synonym to sum named x and I'm not sure what the second does, but neither are needed.

This would make your awk script:

#!/bin/awk

### This script currently prints the total number of rows processed.
### You must edit this script to print the average of the 2nd column
### instead of the number of rows.

# This block of code is executed for each line in the file
{
    sum+=$2
    # The script should NOT print out a value for each line
}
# The END block is processed after the last line is read
END {
    # NR is a variable equal to the number of rows in the file
    print "Average: " sum/ NR
    # Change this to print the Average instead of just the number of rows
}

Jonathan Leffler's answer gives the awk one liner which represents the same fixed code, with the addition of checking that there are at least 1 lines of input (this stops any divide by zero error). If

Pass multiple optional parameters to a C# function

1.You can make overload functions.

SomeF(strin s){}   
SomeF(string s, string s2){}    
SomeF(string s1, string s2, string s3){}   

More info: http://csharpindepth.com/Articles/General/Overloading.aspx

2.or you may create one function with params

SomeF( params string[] paramArray){}
SomeF("aa","bb", "cc", "dd", "ff"); // pass as many as you like

More info: https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/params

3.or you can use simple array

Main(string[] args){}

How to configure CORS in a Spring Boot + Spring Security application?

Found an easy solution for Spring-Boot, Spring-Security and Java-based config:

@Configuration
@EnableWebSecurity
@EnableGlobalMethodSecurity(prePostEnabled = true)
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity httpSecurity) throws Exception {
        httpSecurity.cors().configurationSource(new CorsConfigurationSource() {
            @Override
            public CorsConfiguration getCorsConfiguration(HttpServletRequest request) {
                return new CorsConfiguration().applyPermitDefaultValues();
            }
        });
    }
}

Bootstrap fullscreen layout with 100% height

_x000D_
_x000D_
<section class="min-vh-100 d-flex align-items-center justify-content-center py-3">
  <div class="container">
    <div class="row justify-content-between align-items-center">
    x
    x
    x
    </div>
  </div>
</section>
_x000D_
_x000D_
_x000D_

How to copy a file from remote server to local machine?

I would recommend to use sftp, use this command sftp -oPort=7777 user@host where -oPort is custom port number of ssh , in case if u changed it to 7777, then u can use -oPort, else if use only port 22 then plain sftp user@host which asks for the password , then u can log in, and u can navigate to required location using cd /home/user then a simple command get table u can download it, If u want to download a directory/folder get -r someDirectory will do it. If u want the file permissions also to exist then get -Pr someDirectory. For uploading on to remote change get to put in above commands.

OnClick vs OnClientClick for an asp:CheckBox?

One solution is with JQuery:

$(document).ready(
    function () {
        $('#mycheckboxId').click(function () {
               // here the action or function to call
        });
    }
);

Only numbers. Input number in React

  • To stop typing, use onKeyPress not onChange .

  • Using event.preventDefault() inside onKeyPress means STOP the pressing event .

  • Since keyPress handler is triggered before onChange, you have to check the pressed key (event.keyCode), NOT the current value of input (event.target.value)

    onKeyPress(event) {
      const keyCode = event.keyCode || event.which;
      const keyValue = String.fromCharCode(keyCode);
      if (/\+|-/.test(keyValue))
        event.preventDefault();
    }
    

Demo below

_x000D_
_x000D_
const {Component} = React; _x000D_
_x000D_
class Input extends Component {_x000D_
  _x000D_
_x000D_
  onKeyPress(event) {_x000D_
   const keyCode = event.keyCode || event.which;_x000D_
   const keyValue = String.fromCharCode(keyCode);_x000D_
    if (/\+|-/.test(keyValue))_x000D_
      event.preventDefault();_x000D_
  }_x000D_
  render() {_x000D_
  _x000D_
   return (_x000D_
   <input style={{width: '150px'}} type="number" onKeyPress={this.onKeyPress.bind(this)} />_x000D_
_x000D_
   )_x000D_
  }_x000D_
 _x000D_
}_x000D_
_x000D_
ReactDOM.render(<Input /> , document.querySelector('#app'));
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>_x000D_
_x000D_
<section id="app"></section>
_x000D_
_x000D_
_x000D_

Laravel 5: Retrieve JSON array from $request

My jQuery ajax settings:

        $.ajax({
        headers: {'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')},
        url: url,
        dataType: "json",
        type: "post",
        data: params,
        success: function (resp){
            ....
        },
        error: responseFunc
    });

And now i am able to get the request via $request->all() in Laravel

dataType: "json"

is the important part in the ajax request to handle the response as an json object and not string.

How to set min-height for bootstrap container

Usually, if you are using bootstrap you can do this to set a min-height of 100%.

 <div class="container-fluid min-vh-100"></div>

this will also solve the footer not sticking at the bottom.

you can also do this from CSS with the following class

.stickDamnFooter{min-height: 100vh;}

if this class does not stick your footer just add position: fixed; to that same css class and you will not have this issue in a lifetime. Cheers.

Serialize form data to JSON

Found one possible helper:

https://github.com/theironcook/Backbone.ModelBinder

and for people who don't want to get in contact with forms at all: https://github.com/powmedia/backbone-forms

I will take a closer look at the first link and than give some feedback :)

Print array without brackets and commas

I used join() function like:

i=new Array("Hi", "Hello", "Cheers", "Greetings");
i=i.join("");

Which Prints:
HiHelloCheersGreetings


See more: Javascript Join - Use Join to Make an Array into a String in Javascript

Copy struct to struct in C

Also a good example.....

struct point{int x,y;};
typedef struct point point_t;
typedef struct
{
    struct point ne,se,sw,nw;
}rect_t;
rect_t temp;


int main()
{
//rotate
    RotateRect(&temp);
    return 0;
}

void RotateRect(rect_t *givenRect)
{
    point_t temp_point;
    /*Copy struct data from struct to struct within a struct*/
    temp_point = givenRect->sw;
    givenRect->sw = givenRect->se;
    givenRect->se = givenRect->ne;
    givenRect->ne = givenRect->nw;
    givenRect->nw = temp_point;
}

Max value of Xmx and Xms in Eclipse?

I have tried the following config for eclipse.ini:

org.eclipse.epp.package.jee.product
--launcher.defaultAction
openFile
--launcher.XXMaxPermSize
1024M
-showsplash
org.eclipse.platform
--launcher.XXMaxPermSize
1024m
--launcher.defaultAction
openFile
--launcher.appendVmargs
-vmargs
-Dosgi.requiredJavaVersion=1.6
-Xms128m
-Xmx2048m

Now eclipse performance is about 2 times faster then before.

You can also find a good help ref here: http://help.eclipse.org/indigo/index.jsp?topic=/org.eclipse.platform.doc.isv/reference/misc/runtime-options.html

How to customize <input type="file">?

first of all it's a container:

<div class="upload_file_container">
    Select file!
    <input type="file" name="photo" />
</div>

The second, it's a CSS style, if you want to real more customization, just keeping your eyes is open :)

.upload_file_container{
   width:100px;
   height:40px;
   position:relative;
   background(your img);
}

.upload_file_container input{
   width:100px;
   height:40px;
   position:absolute;
   left:0;
   top:0;
   cursor:pointer;
}

This example hasn't style for text inside the button, it depends on font-size, just correct the height and padding-top values for container

How to add to an existing hash in Ruby

You can use double splat operator which is available since Ruby 2.0:

h = { a: 1, b: 2 }
h = { **h, c: 3 }
p h
# => {:a=>1, :b=>2, :c=>3}

Update int column in table with unique incrementing values

declare @i int  = (SELECT ISNULL(MAX(interfaceID),0) + 1 FROM prices)


update prices
set interfaceID  = @i , @i = @i + 1
where interfaceID is null

should do the work

How to use a variable for a key in a JavaScript object literal?

Given code:

var thetop = 'top';
<something>.stop().animate(
    { thetop : 10 }, 10
);

Translation:

var thetop = 'top';
var config = { thetop : 10 }; // config.thetop = 10
<something>.stop().animate(config, 10);

As you can see, the { thetop : 10 } declaration doesn't make use of the variable thetop. Instead it creates an object with a key named thetop. If you want the key to be the value of the variable thetop, then you will have to use square brackets around thetop:

var thetop = 'top';
var config = { [thetop] : 10 }; // config.top = 10
<something>.stop().animate(config, 10);

The square bracket syntax has been introduced with ES6. In earlier versions of JavaScript, you would have to do the following:

var thetop = 'top';
var config = (
  obj = {},
  obj['' + thetop] = 10,
  obj
); // config.top = 10
<something>.stop().animate(config, 10);

Printing object properties in Powershell

Try this:

Write-Host ($obj | Format-Table | Out-String)

or

Write-Host ($obj | Format-List | Out-String)

How do I specify new lines on Python, when writing on files?

The same way with '\n', though you'd probably not need the '\r'. Is there a reason you have it in your Java version? If you do need/want it, you can use it in the same way in Python too.

Change connection string & reload app.config at run time

Yeah, when ASP.NET web.config gets updated, the whole application gets restarted which means the web.config gets reloaded.

Bootstrap 3: Using img-circle, how to get circle from non-square image?

I use these two methods depending on the usage. FIDDLE

<div class="img-div">
<img src="http://placekitten.com/g/400/200" />
</div>
<div class="circle-image"></div>

div.img-div{
    height:200px;
    width:200px;
    overflow:hidden;
    border-radius:50%;
}

.img-div img{
    -webkit-transform:translate(-50%);
    margin-left:100px;
}

.circle-image{
    width:200px;
    height:200px;
    border-radius:50%;
    background-image:url("http://placekitten.com/g/200/400");
    display:block;
    background-position-y:25% 
}

How to position a CSS triangle using ::after?

You can set triangle with position see this code for reference

.top-left-corner {
    width: 0px;
    height: 0px;
    border-top: 0px solid transparent;
    border-bottom: 55px solid transparent;
    border-left: 55px solid #289006;
    position: absolute;
    left: 0px;
    top: 0px;
}

How to get the integer value of day of week

The correct way to get the integer value of an Enum such as DayOfWeek as a string is:

DayOfWeek.ToString("d")

failed to lazily initialize a collection of role

Lazy exceptions occur when you fetch an object typically containing a collection which is lazily loaded, and try to access that collection.

You can avoid this problem by

  • accessing the lazy collection within a transaction.
  • Initalizing the collection using Hibernate.initialize(obj);
  • Fetch the collection in another transaction
  • Use Fetch profiles to select lazy/non-lazy fetching runtime
  • Set fetch to non-lazy (which is generally not recommended)

Further I would recommend looking at the related links to your right where this question has been answered many times before. Also see Hibernate lazy-load application design.

Is there a CSS selector by class prefix?

This is not possible with CSS selectors. But you could use two classes instead of one, e.g. status and important instead of status-important.

'namespace' but is used like a 'type'

if the error is

Line 26:
Line 27: @foreach (Customers customer in Model) Line 28: { Line 29:

give the full name space
like @foreach (Start.Models.customer customer in Model)

How to wait for a number of threads to complete?

You put all threads in an array, start them all, and then have a loop

for(i = 0; i < threads.length; i++)
  threads[i].join();

Each join will block until the respective thread has completed. Threads may complete in a different order than you joining them, but that's not a problem: when the loop exits, all threads are completed.

MySQL "ERROR 1005 (HY000): Can't create table 'foo.#sql-12c_4' (errno: 150)"

The referenced column must be an index of a single column or the first column in multi column index, and the same type and the same collation.

My two tables have the different collations. It can be shown by issuing show table status like table_name and collation can be changed by issuing alter table table_name convert to character set utf8.

Checking if a variable exists in javascript

if ( typeof variableName !== 'undefined' && variableName )
//// could throw an error if var doesnt exist at all

if ( window.variableName )
//// could be true if var == 0

////further on it depends on what is stored into that var
// if you expect an object to be stored in that var maybe
if ( !!window.variableName )
//could be the right way

best way => see what works for your case

How to enable CORS in apache tomcat

CORS support in Tomcat is provided via a filter. You need to add this filter to your web.xml file and configure it to match your requirements. Full details on the configuration options available can be found in the Tomcat Documentation.

How do I add a library path in cmake?

You had better use find_library command instead of link_directories. Concretely speaking there are two ways:

  1. designate the path within the command

    find_library(NAMES gtest PATHS path1 path2 ... pathN)

  2. set the variable CMAKE_LIBRARY_PATH

    set(CMAKE_LIBRARY_PATH path1 path2)
    find_library(NAMES gtest)

the reason is as flowings:

Note This command is rarely necessary and should be avoided where there are other choices. Prefer to pass full absolute paths to libraries where possible, since this ensures the correct library will always be linked. The find_library() command provides the full path, which can generally be used directly in calls to target_link_libraries(). Situations where a library search path may be needed include: Project generators like Xcode where the user can switch target architecture at build time, but a full path to a library cannot be used because it only provides one architecture (i.e. it is not a universal binary).

Libraries may themselves have other private library dependencies that expect to be found via RPATH mechanisms, but some linkers are not able to fully decode those paths (e.g. due to the presence of things like $ORIGIN).

If a library search path must be provided, prefer to localize the effect where possible by using the target_link_directories() command rather than link_directories(). The target-specific command can also control how the search directories propagate to other dependent targets.

How to call Stored Procedure in Entity Framework 6 (Code-First)?

All you have to do is create an object that has the same property names as the results returned by the stored procedure. For the following stored procedure:

    CREATE PROCEDURE [dbo].[GetResultsForCampaign]  
    @ClientId int   
    AS
    BEGIN
    SET NOCOUNT ON;

    SELECT AgeGroup, Gender, Payout
    FROM IntegrationResult
    WHERE ClientId = @ClientId
    END

create a class that looks like:

    public class ResultForCampaign
    {
        public string AgeGroup { get; set; }

        public string Gender { get; set; }

        public decimal Payout { get; set; }
    }

and then call the procedure by doing the following:

    using(var context = new DatabaseContext())
    {
            var clientIdParameter = new SqlParameter("@ClientId", 4);

            var result = context.Database
                .SqlQuery<ResultForCampaign>("GetResultsForCampaign @ClientId", clientIdParameter)
                .ToList();
    }

The result will contain a list of ResultForCampaign objects. You can call SqlQuery using as many parameters as needed.

Program to find prime numbers

Here is a solution with unit test:

The solution:

public class PrimeNumbersKata
    {
        public int CountPrimeNumbers(int n)
        {
            if (n < 0) throw new ArgumentException("Not valide numbre");
            if (n == 0 || n == 1) return 0;
            int cpt = 0;
            for (int i = 2; i <= n; i++)
            {
                if (IsPrimaire(i)) cpt++;
            }
            return cpt;
        }

        private bool IsPrimaire(int number)
        {

            for (int i = 2; i <= number / 2; i++)
            {
                if (number % i == 0) return false;
            }
            return true;
        }
    }

The tests:

[TestFixture]
    class PrimeNumbersKataTest
    {
        private PrimeNumbersKata primeNumbersKata;
        [SetUp]
        public void Init()
        {
            primeNumbersKata = new PrimeNumbersKata();
        }
        [TestCase(1,0)]
        [TestCase(0,0)]
        [TestCase(2,1)]
        [TestCase(3,2)]
        [TestCase(5,3)]
        [TestCase(7,4)]
        [TestCase(9,4)]
        [TestCase(11,5)]
        [TestCase(13,6)]
        public void CountPrimeNumbers_N_AsArgument_returnCountPrimes(int n, int expected)
        {
            //arrange
            //act
            var actual = primeNumbersKata.CountPrimeNumbers(n);
            //assert
            Assert.AreEqual(expected,actual);
        }

        [Test]
        public void CountPrimairs_N_IsNegative_RaiseAnException()
        {
            var ex = Assert.Throws<ArgumentException>(()=> { primeNumbersKata.CountPrimeNumbers(-1); });
            //Assert.That(ex.Message == "Not valide numbre");
             Assert.That(ex.Message, Is.EqualTo("Not valide numbre"));

        }
    }

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 safely call an async method in C# without await

This is called fire and forget, and there is an extension for that.

Consumes a task and doesn't do anything with it. Useful for fire-and-forget calls to async methods within async methods.

Install nuget package.

Use:

MyAsyncMethod().Forget();

Alternative for <blink>

If you're looking to re-enable the blink tag for your own browsing, you can install this simple Chrome extension I wrote: https://github.com/etlovett/Blink-Tag-Enabler-Chrome-Extension. It just hides and shows all <blink> tags on every page using setInterval.

Text overflow ellipsis on two lines

Use this if above is not working

 display: -webkit-box;
 max-width: 100%;
 margin: 0 auto;
 -webkit-line-clamp: 2;
 /* autoprefixer: off */
 -webkit-box-orient: vertical;
 /* autoprefixer: on */
 overflow: hidden;
 text-overflow: ellipsis;

sorting and paging with gridview asp.net

I found a much easier way, which allows you to still use the built in sorting/paging of the standard gridview...

create 2 labels. set them to be visible = false. I called mine lblSort1 and lblSortDirection1

then code 2 simple events... the page sorting, which writes to the text of the invisible labels, and the page index changing, which uses them...

Private Sub gridview_Sorting(sender As Object, e As GridViewSortEventArgs) Handles gridview.Sorting
lblSort1.Text = e.SortExpression
lblSortDirection1.Text = e.SortDirection
End Sub

Private Sub gridview_PageIndexChanging(sender As Object, e As GridViewPageEventArgs) Handles gridview.PageIndexChanging
    gridview.Sort(lblSort1.Text, CInt(lblSortDirection1.Text))
End Sub

this is a little sloppier than using global variables, but I've found with asp especially that global vars are, well, unreliable...

The easiest way to transform collection to array?

For example, you have collection ArrayList with elements Student class:

List stuList = new ArrayList();
Student s1 = new Student("Raju");
Student s2 = new Student("Harish");
stuList.add(s1);
stuList.add(s2);
//now you can convert this collection stuList to Array like this
Object[] stuArr = stuList.toArray();           // <----- toArray() function will convert collection to array

Bloomberg BDH function with ISIN

I had the same problem. Here's what I figured out:

=BDP(A1&"@BGN Corp", "Issuer_parent_eqy_ticker")

A1 being the ISINs. This will return the ticker number. Then just use the ticker number to get the price.

How to write text in ipython notebook?

Change the cell type to Markdown in the menu bar, from Code to Markdown. Currently in Notebook 4.x, the keyboard shortcut for such an action is: Esc (for command mode), then m (for markdown).

Add button to a layout programmatically

This line:

layout = (LinearLayout) findViewById(R.id.statsviewlayout);

Looks for the "statsviewlayout" id in your current 'contentview'. Now you've set that here:

setContentView(new GraphTemperature(getApplicationContext()));

And i'm guessing that new "graphTemperature" does not set anything with that id.

It's a common mistake to think you can just find any view with findViewById. You can only find a view that is in the XML (or appointed by code and given an id).

The nullpointer will be thrown because the layout you're looking for isn't found, so

layout.addView(buyButton);

Throws that exception.

addition: Now if you want to get that view from an XML, you should use an inflater:

layout = (LinearLayout) View.inflate(this, R.layout.yourXMLYouWantToLoad, null);

assuming that you have your linearlayout in a file called "yourXMLYouWantToLoad.xml"

Is there a math nCr function in python?

Do you want iteration? itertools.combinations. Common usage:

>>> import itertools
>>> itertools.combinations('abcd',2)
<itertools.combinations object at 0x01348F30>
>>> list(itertools.combinations('abcd',2))
[('a', 'b'), ('a', 'c'), ('a', 'd'), ('b', 'c'), ('b', 'd'), ('c', 'd')]
>>> [''.join(x) for x in itertools.combinations('abcd',2)]
['ab', 'ac', 'ad', 'bc', 'bd', 'cd']

If you just need to compute the formula, use math.factorial:

import math

def nCr(n,r):
    f = math.factorial
    return f(n) / f(r) / f(n-r)

if __name__ == '__main__':
    print nCr(4,2)

In Python 3, use the integer division // instead of / to avoid overflows:

return f(n) // f(r) // f(n-r)

Output

6

How to change color of Android ListView separator line?

Use android:divider="#FF0000" and android:dividerHeight="2px" for ListView.

<ListView 
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:divider="#0099FF"
android:dividerHeight="2px"/>

Java method to swap primitives

Try this magic

public static <T> void swap(T a, T b) {
    try {
        Field[] fields = a.getClass().getDeclaredFields();
        for (Field field : fields) {
            field.setAccessible(true);
            Object temp = field.get(a);
            field.set(a, field.get(b));
            field.set(b, temp);
        }
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    }
}

And test it!

    System.out.println("a:" + a);
    System.out.println("b:" + b);
    swap(a,b);
    System.out.println("a:" + a);
    System.out.println("b:" + b);

What does "exited with code 9009" mean during this build?

Error Code 9009 means error file not found. All the underlying reasons posted in the answers here are good inspiration to figure out why, but the error itself simply means a bad path.

Cannot install signed apk to device manually, got error "App not installed"

You don't have to uninstall the Google Play version if App Signing by Google Play is enabled for your app, follow the steps:
1. Make a signed version of your app with your release key
2. Go to Google Play Developer console
3. Create a closed track release (alpha or beta release) with the new signed version of your app
4. You can now download the apk signed by App Signing by Google Play, choose derived APKenter image description here

  1. Install the downloaded derived APK

The reason is App Signing by Google Play signs release apps with different keys, if you have an app installed from Play Store, and you want to test the new release version app (generated from Android Studio) in your phone, "App not installed" happens since the old version and the new version were signed by two different keys: one with App Signing by Google Play and one with your key.

How to Solve Max Connection Pool Error

Here's what u can also try....

run your application....while it is still running launch your command prompt

while your application is running type netstat -n on the command prompt. You should see a list of TCP/IP connections. Check if your list is not very long. Ideally you should have less than 5 connections in the list. Check the status of the connections.
If you have too many connections with a TIME_WAIT status it means the connection has been closed and is waiting for the OS to release the resources. If you are running on Windows, the default ephemeral port rang is between 1024 and 5000 and the default time it takes Windows to release the resource from TIME_WAIT status is 4 minutes. So if your application used more then 3976 connections in less then 4 minutes, you will get the exception you got.

Suggestions to fix it:

  1. Add a connection pool to your connection string.

If you continue to receive the same error message (which is highly unlikely) you can then try the following: (Please don't do it if you are not familiar with the Windows registry)

  1. Run regedit from your run command. In the registry editor look for this registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters:

Modify the settings so they read:

MaxUserPort = dword:00004e20 (10,000 decimal) TcpTimedWaitDelay = dword:0000001e (30 decimal)

This will increase the number of ports to 10,000 and reduce the time to release freed tcp/ip connections.

Only use suggestion 2 if 1 fails.

Thank you.

How to install a specific version of a package with pip?

Use ==:

pip install django_modeltranslation==0.4.0-beta2

How to download and save an image in Android

@Droidman post is pretty comprehensive. Volley works good with small data of few kbytes. When I tried to use the 'BasicImageDownloader.java' the Android Studio gave me warning that the AsyncTask class should to be static or there could be leaks. I used Volley in another test app and that kept crashing because of leaks so I am worried about using Volley for the image downloader (images can be few 100 kB).

I used Picasso and it worked well, there is small change (probably an update on Picasso) from what is posted above. Below code worked for me:

    public static void imageDownload(Context ctx, String url){
    Picasso.get().load(yourURL)
            .into(getTarget(url));
}
private static Target getTarget(final String url){

    Target target2 = new Target() {
        @Override
        public void onBitmapLoaded(final Bitmap bitmap, Picasso.LoadedFrom from) {
            new Thread(new Runnable() {

                @Override
                public void run() {

                    File file = new File(localPath + "/"+"YourImageFile.jpg");
                    try {
                        file.createNewFile();
                        FileOutputStream ostream = new FileOutputStream(file);
                        bitmap.compress(Bitmap.CompressFormat.JPEG, 80, ostream);
                        ostream.flush();
                        ostream.close();
                    } catch (IOException e) {
                        Log.e("IOException", e.getLocalizedMessage());
                    }
                }
            }).start();
        }

        @Override
        public void onBitmapFailed(Exception e, Drawable errorDrawable) {
        }

        @Override
        public void onPrepareLoad(Drawable placeHolderDrawable) {
        }
    };
    return target;
}

UTF-8 text is garbled when form is posted as multipart/form-data

Just use Apache commons upload library. Add URIEncoding="UTF-8" to Tomcat's connector, and use FileItem.getString("UTF-8") instead of FileItem.getString() without charset specified.

Hope this help.

How do I force my .NET application to run as administrator?

I implemented some code to do it manually:

using System.Security.Principal;
public bool IsUserAdministrator()
{
    bool isAdmin;
    try
    {
        WindowsIdentity user = WindowsIdentity.GetCurrent();
        WindowsPrincipal principal = new WindowsPrincipal(user);
        isAdmin = principal.IsInRole(WindowsBuiltInRole.Administrator);
    }
    catch (UnauthorizedAccessException ex)
    {
        isAdmin = false;
    }
    catch (Exception ex)
    {
        isAdmin = false;
    }
    return isAdmin;
}