Programs & Examples On #Image scaling

The use of interpolation to spatially stretch or squeeze an image by manipulating the underlying image data -- directly, or through API or ABI calls.

How to scale a BufferedImage

As @Bozho says, you probably want to use getScaledInstance.

To understand how grph.scale(2.0, 2.0) works however, you could have a look at this code:

import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;


class Main {
    public static void main(String[] args) throws IOException {

        final int SCALE = 2;

        Image img = new ImageIcon("duke.png").getImage();

        BufferedImage bi = new BufferedImage(SCALE * img.getWidth(null),
                                             SCALE * img.getHeight(null),
                                             BufferedImage.TYPE_INT_ARGB);

        Graphics2D grph = (Graphics2D) bi.getGraphics();
        grph.scale(SCALE, SCALE);

        // everything drawn with grph from now on will get scaled.

        grph.drawImage(img, 0, 0, null);
        grph.dispose();

        ImageIO.write(bi, "png", new File("duke_double_size.png"));
    }
}

Given duke.png:
enter image description here

it produces duke_double_size.png:
enter image description here

Resizing an Image without losing any quality

See if you like the image resizing quality of this open source ASP.NET module. There's a live demo, so you can mess around with it yourself. It yields results that are (to me) impossible to distinguish from Photoshop output. It also has similar file sizes - MS did a good job on their JPEG encoder.

How to scale an Image in ImageView to keep the aspect ratio

Pass your ImageView and based on screen height and width you can make it

    public void setScaleImage(EventAssetValueListenerView view){
        // Get the ImageView and its bitmap
        Drawable drawing = view.getDrawable();
        Bitmap bitmap = ((BitmapDrawable)drawing).getBitmap();
        // Get current dimensions
        int width = bitmap.getWidth();
        int height = bitmap.getHeight();

        float xScale = ((float) 4) / width;
        float yScale = ((float) 4) / height;
        float scale = (xScale <= yScale) ? xScale : yScale;

        Matrix matrix = new Matrix();
        matrix.postScale(scale, scale);

        Bitmap scaledBitmap = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
        BitmapDrawable result = new BitmapDrawable(scaledBitmap);
        width = scaledBitmap.getWidth();
        height = scaledBitmap.getHeight();

        view.setImageDrawable(result);

        LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) view.getLayoutParams();
        params.width = width;
        params.height = height;
        view.setLayoutParams(params);
    }

HTML img scaling

The best way I know how to do this, is:

1) set overflow to scroll and that way the image would stay in but you can scroll to see it instead

2) upload a smaller image. Now there are plenty of programs out there when uploading (you'll need something like PHP or .net to do this btw) you can have it auto scale.

3) Living with it and setting the width and height, this although will make it look distorted but the right size will still result in the user having to download the full-sized image.

Good luck!

c# Image resizing to different size while preserving aspect ratio

Note: this code resizes and removes everything outside the aspect ratio instead of padding it..

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;

namespace MyPhotos.Common
{
    public class ThumbCreator
    {

        public enum VerticalAlign
        {
            Top,
            Middle,
            Bottom
        }

        public enum HorizontalAlign
        {
            Left,
            Middle,
            Right
        }

        public void Convert(string sourceFile, string targetFile, ImageFormat targetFormat, int height, int width, VerticalAlign valign, HorizontalAlign halign)
        {
            using (Image img = Image.FromFile(sourceFile))
            {
                using (Image targetImg = Convert(img, height, width, valign, halign))
                {
                    string directory = Path.GetDirectoryName(targetFile);
                    if (!Directory.Exists(directory))
                    {
                        Directory.CreateDirectory(directory);
                    }
                    if (targetFormat == ImageFormat.Jpeg)
                    {
                        SaveJpeg(targetFile, targetImg, 100);
                    }
                    else
                    {
                        targetImg.Save(targetFile, targetFormat);
                    }
                }
            }
        }

        /// <summary> 
        /// Saves an image as a jpeg image, with the given quality 
        /// </summary> 
        /// <param name="path">Path to which the image would be saved.</param> 
        // <param name="quality">An integer from 0 to 100, with 100 being the 
        /// highest quality</param> 
        public static void SaveJpeg(string path, Image img, int quality)
        {
            if (quality < 0 || quality > 100)
                throw new ArgumentOutOfRangeException("quality must be between 0 and 100.");


            // Encoder parameter for image quality 
            EncoderParameter qualityParam =
                new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
            // Jpeg image codec 
            ImageCodecInfo jpegCodec = GetEncoderInfo("image/jpeg");

            EncoderParameters encoderParams = new EncoderParameters(1);
            encoderParams.Param[0] = qualityParam;

            img.Save(path, jpegCodec, encoderParams);
        }

        /// <summary> 
        /// Returns the image codec with the given mime type 
        /// </summary> 
        private static ImageCodecInfo GetEncoderInfo(string mimeType)
        {
            // Get image codecs for all image formats 
            ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();

            // Find the correct image codec 
            for (int i = 0; i < codecs.Length; i++)
                if (codecs[i].MimeType == mimeType)
                    return codecs[i];
            return null;
        }

        public Image Convert(Image img, int height, int width, VerticalAlign valign, HorizontalAlign halign)
        {
            Bitmap result = new Bitmap(width, height);
            using (Graphics g = Graphics.FromImage(result))
            {
                g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                float ratio = (float)height / (float)img.Height;
                int temp = (int)((float)img.Width * ratio);
                if (temp == width)
                {
                    //no corrections are needed!
                    g.DrawImage(img, 0, 0, width, height);
                    return result;
                }
                else if (temp > width)
                {
                    //den e för bred!
                    int overFlow = (temp - width);
                    if (halign == HorizontalAlign.Middle)
                    {
                        g.DrawImage(img, 0 - overFlow / 2, 0, temp, height);
                    }
                    else if (halign == HorizontalAlign.Left)
                    {
                        g.DrawImage(img, 0, 0, temp, height);
                    }
                    else if (halign == HorizontalAlign.Right)
                    {
                        g.DrawImage(img, -overFlow, 0, temp, height);
                    }
                }
                else
                {
                    //den e för hög!
                    ratio = (float)width / (float)img.Width;
                    temp = (int)((float)img.Height * ratio);
                    int overFlow = (temp - height);
                    if (valign == VerticalAlign.Top)
                    {
                        g.DrawImage(img, 0, 0, width, temp);
                    }
                    else if (valign == VerticalAlign.Middle)
                    {
                        g.DrawImage(img, 0, -overFlow / 2, width, temp);
                    }
                    else if (valign == VerticalAlign.Bottom)
                    {
                        g.DrawImage(img, 0, -overFlow, width, temp);
                    }
                }
            }
            return result;
        }
    }
}

High Quality Image Scaling Library

Try the different values for Graphics.InterpolationMode. There are several typical scaling algorithms available in GDI+. If one of these is sufficient for your need, you can go this route instead of relying on an external library.

jQuery get mouse position within an element

If you make your parent element be "position: relative", then it will be the "offset parent" for the stuff you're tracking mouse events over. Thus the jQuery "position()" will be relative to that.

Running Git through Cygwin from Windows

call your (windows-)git with cygpath as parameter, in order to convert the "calling path". I m confused why that should be a problem.

How to validate phone number using PHP?

Since phone numbers must conform to a pattern, you can use regular expressions to match the entered phone number against the pattern you define in regexp.

php has both ereg and preg_match() functions. I'd suggest using preg_match() as there's more documentation for this style of regex.

An example

$phone = '000-0000-0000';

if(preg_match("/^[0-9]{3}-[0-9]{4}-[0-9]{4}$/", $phone)) {
  // $phone is valid
}

Java 8 Lambda filter by Lists

Look this:

List<Client> result = clients
    .stream()
    .filter(c -> 
        (users.stream().map(User::getName).collect(Collectors.toList())).contains(c.getName()))
        .collect(Collectors.toList());

How do I upload a file with metadata using a REST web service?

If your file and its metadata creating one resource, its perfectly fine to upload them both in one request. Sample request would be :

POST https://target.com/myresources/resourcename HTTP/1.1

Accept: application/json

Content-Type: multipart/form-data; 

boundary=-----------------------------28947758029299

Host: target.com

-------------------------------28947758029299

Content-Disposition: form-data; name="application/json"

{"markers": [
        {
            "point":new GLatLng(40.266044,-74.718479), 
            "homeTeam":"Lawrence Library",
            "awayTeam":"LUGip",
            "markerImage":"images/red.png",
            "information": "Linux users group meets second Wednesday of each month.",
            "fixture":"Wednesday 7pm",
            "capacity":"",
            "previousScore":""
        },
        {
            "point":new GLatLng(40.211600,-74.695702),
            "homeTeam":"Hamilton Library",
            "awayTeam":"LUGip HW SIG",
            "markerImage":"images/white.png",
            "information": "Linux users can meet the first Tuesday of the month to work out harward and configuration issues.",
            "fixture":"Tuesday 7pm",
            "capacity":"",
            "tv":""
        },
        {
            "point":new GLatLng(40.294535,-74.682012),
            "homeTeam":"Applebees",
            "awayTeam":"After LUPip Mtg Spot",
            "markerImage":"images/newcastle.png",
            "information": "Some of us go there after the main LUGip meeting, drink brews, and talk.",
            "fixture":"Wednesday whenever",
            "capacity":"2 to 4 pints",
            "tv":""
        },
] }

-------------------------------28947758029299

Content-Disposition: form-data; name="name"; filename="myfilename.pdf"

Content-Type: application/octet-stream

%PDF-1.4
%
2 0 obj
<</Length 57/Filter/FlateDecode>>stream
x+r
26S00SI2P0Qn
F
!i\
)%[email protected]
[
endstream
endobj
4 0 obj
<</Type/Page/MediaBox[0 0 595 842]/Resources<</Font<</F1 1 0 R>>>>/Contents 2 0 R/Parent 3 0 R>>
endobj
1 0 obj
<</Type/Font/Subtype/Type1/BaseFont/Helvetica/Encoding/WinAnsiEncoding>>
endobj
3 0 obj
<</Type/Pages/Count 1/Kids[4 0 R]>>
endobj
5 0 obj
<</Type/Catalog/Pages 3 0 R>>
endobj
6 0 obj
<</Producer(iTextSharp 5.5.11 2000-2017 iText Group NV \(AGPL-version\))/CreationDate(D:20170630120636+02'00')/ModDate(D:20170630120636+02'00')>>
endobj
xref
0 7
0000000000 65535 f 
0000000250 00000 n 
0000000015 00000 n 
0000000338 00000 n 
0000000138 00000 n 
0000000389 00000 n 
0000000434 00000 n 
trailer
<</Size 7/Root 5 0 R/Info 6 0 R/ID [<c7c34272c2e618698de73f4e1a65a1b5><c7c34272c2e618698de73f4e1a65a1b5>]>>
%iText-5.5.11
startxref
597
%%EOF

-------------------------------28947758029299--

Get an image extension from an uploaded file in Laravel

Yet another way to do it:

//Where $file is an instance of Illuminate\Http\UploadFile
$extension = $file->getClientOriginalExtension();

Get webpage contents with Python?

Also you can use faster_than_requests package. That's very fast and simple:

import faster_than_requests as r
content = r.get2str("http://test.com/")

Look at this comparison:

enter image description here

Accessing UI (Main) Thread safely in WPF

The best way to go about it would be to get a SynchronizationContext from the UI thread and use it. This class abstracts marshalling calls to other threads, and makes testing easier (in contrast to using WPF's Dispatcher directly). For example:

class MyViewModel
{
    private readonly SynchronizationContext _syncContext;

    public MyViewModel()
    {
        // we assume this ctor is called from the UI thread!
        _syncContext = SynchronizationContext.Current;
    }

    // ...

    private void watcher_Changed(object sender, FileSystemEventArgs e)
    {
         _syncContext.Post(o => DGAddRow(crp.Protocol, ft), null);
    }
}

JS: iterating over result of getElementsByClassName using Array.forEach

As already said, getElementsByClassName returns a HTMLCollection, which is defined as

[Exposed=Window]
interface HTMLCollection {
  readonly attribute unsigned long length;
  getter Element? item(unsigned long index);
  getter Element? namedItem(DOMString name);
};

Previously, some browsers returned a NodeList instead.

[Exposed=Window]
interface NodeList {
  getter Node? item(unsigned long index);
  readonly attribute unsigned long length;
  iterable<Node>;
};

The difference is important, because DOM4 now defines NodeLists as iterable.

According to Web IDL draft,

Objects implementing an interface that is declared to be iterable support being iterated over to obtain a sequence of values.

Note: In the ECMAScript language binding, an interface that is iterable will have “entries”, “forEach”, “keys”, “values” and @@iterator properties on its interface prototype object.

That means that, if you want to use forEach, you can use a DOM method which returns a NodeList, like querySelectorAll.

document.querySelectorAll(".myclass").forEach(function(element, index, array) {
  // do stuff
});

Note this is not widely supported yet. Also see forEach method of Node.childNodes?

App.settings - the Angular way?

It's not advisable to use the environment.*.ts files for your API URL configuration. It seems like you should because this mentions the word "environment".

Using this is actually compile-time configuration. If you want to change the API URL, you will need to re-build. That's something you don't want to have to do ... just ask your friendly QA department :)

What you need is runtime configuration, i.e. the app loads its configuration when it starts up.

Some other answers touch on this, but the difference is that the configuration needs to be loaded as soon as the app starts, so that it can be used by a normal service whenever it needs it.

To implement runtime configuration:

  1. Add a JSON config file to the /src/assets/ folder (so that is copied on build)
  2. Create an AppConfigService to load and distribute the config
  3. Load the configuration using an APP_INITIALIZER

1. Add Config file to /src/assets

You could add it to another folder, but you'd need to tell the CLI that it is an asset in the angular.json. Start off using the assets folder:

{
  "apiBaseUrl": "https://development.local/apiUrl"
}

2. Create AppConfigService

This is the service which will be injected whenever you need the config value:

@Injectable({
  providedIn: 'root'
})
export class AppConfigService {

  private appConfig: any;

  constructor(private http: HttpClient) { }

  loadAppConfig() {
    return this.http.get('/assets/config.json')
      .toPromise()
      .then(data => {
        this.appConfig = data;
      });
  }

  // This is an example property ... you can make it however you want.
  get apiBaseUrl() {

    if (!this.appConfig) {
      throw Error('Config file not loaded!');
    }

    return this.appConfig.apiBaseUrl;
  }
}

3. Load the configuration using an APP_INITIALIZER

To allow the AppConfigService to be injected safely, with config fully loaded, we need to load the config at app startup time. Importantly, the initialisation factory function needs to return a Promise so that Angular knows to wait until it finishes resolving before finishing startup:

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    HttpClientModule
  ],
  providers: [
    {
      provide: APP_INITIALIZER,
      multi: true,
      deps: [AppConfigService],
      useFactory: (appConfigService: AppConfigService) => {
        return () => {
          //Make sure to return a promise!
          return appConfigService.loadAppConfig();
        };
      }
    }
  ],
  bootstrap: [AppComponent]
})
export class AppModule { }

Now you can inject it wherever you need to and all the config will be ready to read:

@Component({
  selector: 'app-test',
  templateUrl: './test.component.html',
  styleUrls: ['./test.component.scss']
})
export class TestComponent implements OnInit {

  apiBaseUrl: string;

  constructor(private appConfigService: AppConfigService) {}

  ngOnInit(): void {
    this.apiBaseUrl = this.appConfigService.apiBaseUrl;
  }

}

I can't say it strongly enough, configuring your API urls as compile-time configuration is an anti-pattern. Use runtime configuration.

Truncating all tables in a Postgres database

Could you use dynamic SQL to execute each statement in turn? You would probably have to write a PL/pgSQL script to do this.

http://www.postgresql.org/docs/8.3/static/plpgsql-statements.html (section 38.5.4. Executing Dynamic Commands)

How to correctly use "section" tag in HTML5?

that’s just wrong: is not a wrapper. The element denotes a semantic section of your content to help construct a document outline. It should contain a heading. If you’re looking for a page wrapper element (for any flavour of HTML or XHTML), consider applying styles directly to the element as described by Kroc Camen. If you still need an additional element for styling, use a . As Dr Mike explains, div isn’t dead, and if there’s nothing else more appropriate, it’s probably where you really want to apply your CSS.

you can check this : http://html5doctor.com/avoiding-common-html5-mistakes/

cell format round and display 2 decimal places

I use format, Number, 2 decimal places & tick ' use 1000 separater ', then go to 'File', 'Options', 'Advanced', scroll down to 'When calculating this workbook' and tick 'set precision as displayed'. You get an error message about losing accuracy, that's good as it means it is rounding to 2 decimal places. So much better than bothering with adding a needless ROUND function.

socket.shutdown vs socket.close

Explanation of shutdown and close: Graceful shutdown (msdn)

Shutdown (in your case) indicates to the other end of the connection there is no further intention to read from or write to the socket. Then close frees up any memory associated with the socket.

Omitting shutdown may cause the socket to linger in the OSs stack until the connection has been closed gracefully.

IMO the names 'shutdown' and 'close' are misleading, 'close' and 'destroy' would emphasise their differences.

Creating an empty bitmap and drawing though canvas in Android

Do not use Bitmap.Config.ARGB_8888

Instead use int w = WIDTH_PX, h = HEIGHT_PX;

Bitmap.Config conf = Bitmap.Config.ARGB_4444; // see other conf types
Bitmap bmp = Bitmap.createBitmap(w, h, conf); // this creates a MUTABLE bitmap
Canvas canvas = new Canvas(bmp);

// ready to draw on that bitmap through that canvas

ARGB_8888 can land you in OutOfMemory issues when dealing with more bitmaps or large bitmaps. Or better yet, try avoiding usage of ARGB option itself.

php - How do I fix this illegal offset type error

I had a similar problem. As I got a Character from my XML child I had to convert it first to a String (or Integer, if you expect one). The following shows how I solved the problem.

foreach($xml->children() as $newInstr){
        $iInstrument = new Instrument($newInstr['id'],$newInstr->Naam,$newInstr->Key);
        $arrInstruments->offsetSet((String)$iInstrument->getID(), $iInstrument);
    }

How do I export (and then import) a Subversion repository?

I found an article about how to move svn repositories from a hosting service to another, and how to do local backups:

  1. Define where you will store your repositories:

    mkdir ~/repo
    MYREPO=/home/me/someplace ## you should use full path here
    
  2. Now create a empty svn repository with svnadmin create $MYREPO
  3. Create a hook file and make it executable:

    echo '#!/bin/sh' > $MYREPO/hooks/pre-revprop-change
    chmod +x $MYREPO/hooks/pre-revprop-change
    
  4. Now we can start importing the repository with svnsync, that will initialize a destination repository for synchronization from another repository:

    svnsync init file://$MYREPO http://your.svn.repo.here/
    
  5. And the finishing touch to transfer all pending revisions to the destination from the source with which it was initialized:

    svnsync sync file://$MYREPO
    

There now you have a local svn repository in the ~/repo directory.

Source:

python 2 instead of python 3 as the (temporary) default python?

Use python command to launch scripts, not shell directly. E.g.

  python2 /usr/bin/command

AFAIK this is the recommended method to workaround scripts with bad env interpreter line.

What is a "thread" (really)?

I am going to use a lot of text from the book Operating Systems Concepts by ABRAHAM SILBERSCHATZ, PETER BAER GALVIN and GREG GAGNE along with my own understanding of things.

Process

Any application resides in the computer in the form of text (or code).

We emphasize that a program by itself is not a process. A program is a passive entity, such as a file containing a list of instructions stored on disk (often called an executable file).

When we start an application, we create an instance of execution. This instance of execution is called a process. EDIT:(As per my interpretation, analogous to a class and an instance of a class, the instance of a class being a process. )

An example of processes is that of Google Chrome. When we start Google Chrome, 3 processes are spawned:

• The browser process is responsible for managing the user interface as well as disk and network I/O. A new browser process is created when Chrome is started. Only one browser process is created.

Renderer processes contain logic for rendering web pages. Thus, they contain the logic for handling HTML, Javascript, images, and so forth. As a general rule, a new renderer process is created for each website opened in a new tab, and so several renderer processes may be active at the same time.

• A plug-in process is created for each type of plug-in (such as Flash or QuickTime) in use. Plug-in processes contain the code for the plug-in as well as additional code that enables the plug-in to communicate with associated renderer processes and the browser process.

Thread

To answer this I think you should first know what a processor is. A Processor is the piece of hardware that actually performs the computations. EDIT: (Computations like adding two numbers, sorting an array, basically executing the code that has been written)

Now moving on to the definition of a thread.

A thread is a basic unit of CPU utilization; it comprises a thread ID, a program counter, a register set, and a stack.

EDIT: Definition of a thread from intel's website:

A Thread, or thread of execution, is a software term for the basic ordered sequence of instructions that can be passed through or processed by a single CPU core.

So, if the Renderer process from the Chrome application sorts an array of numbers, the sorting will take place on a thread/thread of execution. (The grammar regarding threads seems confusing to me)

My Interpretation of Things

A process is an execution instance. Threads are the actual workers that perform the computations via CPU access. When there are multiple threads running for a process, the process provides common memory.

EDIT: Other Information that I found useful to give more context

All modern day computer have more than one threads. The number of threads in a computer depends on the number of cores in a computer.

Concurrent Computing:

From Wikipedia:

Concurrent computing is a form of computing in which several computations are executed during overlapping time periods—concurrently—instead of sequentially (one completing before the next starts). This is a property of a system—this may be an individual program, a computer, or a network—and there is a separate execution point or "thread of control" for each computation ("process").

So, I could write a program which calculates the sum of 4 numbers:

(1 + 3) + (4 + 5)

In the program to compute this sum (which will be one process running on a thread of execution) I can fork another process which can run on a different thread to compute (4 + 5) and return the result to the original process, while the original process calculates the sum of (1 + 3).

How to tell if UIViewController's view is visible

For over-full-screen or over-context modal presentation, "is visible" could mean it is on top of the view controller stack or just visible but covered by another view controller.

To check if the view controller "is the top view controller" is quite different from "is visible", you should check the view controller's navigation controller's view controller stack.

I wrote a piece of code to solve this problem:

extension UIViewController {
    public var isVisible: Bool {
        if isViewLoaded {
            return view.window != nil
        }
        return false
    }

    public var isTopViewController: Bool {
        if self.navigationController != nil {
            return self.navigationController?.visibleViewController === self
        } else if self.tabBarController != nil {
            return self.tabBarController?.selectedViewController == self && self.presentedViewController == nil
        } else {
            return self.presentedViewController == nil && self.isVisible
        }
    }
}

Check if checkbox is checked with jQuery

use code below

<script>

$(document).ready(function () {
  $("[id$='chkSendMail']").attr("onchange", "ShowMailSection()");
}

function ShowMailSection() {
  if ($("[id$='chkSendMail'][type='checkbox']:checked").length >0){
      $("[id$='SecEmail']").removeClass("Hide");
  }
</script>

Mongoose delete array element in document and save

Since favorites is an array, you just need to splice it off and save the document.

var mongoose = require('mongoose'),
    Schema = mongoose.Schema;

var favorite = new Schema({
    cn: String,
    favorites: Array
});

module.exports = mongoose.model('Favorite', favorite);

exports.deleteFavorite = function (req, res, next) {
    if (req.params.callback !== null) {
        res.contentType = 'application/javascript';
    }
    // Changed to findOne instead of find to get a single document with the favorites.
    Favorite.findOne({cn: req.params.name}, function (error, doc) {
        if (error) {
            res.send(null, 500);
        } else if (doc) {
            var records = {'records': doc};
            // find the delete uid in the favorites array
            var idx = doc.favorites ? doc.favorites.indexOf(req.params.deleteUid) : -1;
            // is it valid?
            if (idx !== -1) {
                // remove it from the array.
                doc.favorites.splice(idx, 1);
                // save the doc
                doc.save(function(error) {
                    if (error) {
                        console.log(error);
                        res.send(null, 500);
                    } else {
                        // send the records
                        res.send(records);
                    }
                });
                // stop here, otherwise 404
                return;
            }
        }
        // send 404 not found
        res.send(null, 404);
    });
};

How get permission for camera in android.(Specifically Marshmallow)

This works for me, the source is here

int MY_PERMISSIONS_REQUEST_CAMERA=0;
// Here, this is the current activity
if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED)
{
     if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA))
     {

     }
     else
     {
          ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.CAMERA}, MY_PERMISSIONS_REQUEST_CAMERA );
          // MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
          // app-defined int constant. The callback method gets the
          // result of the request.
      }
}

The calling thread cannot access this object because a different thread owns it

For some reason Candide's answer didn't build. It was helpful, though, as it led me to find this, which worked perfectly:

System.Windows.Threading.Dispatcher.CurrentDispatcher.Invoke((Action)(() =>
{
   //your code here...
}));

Selecting an element in iFrame jQuery

If the case is accessing the IFrame via console, e. g. Chrome Dev Tools then you can just select the context of DOM requests via dropdown (see the picture).

Chrome Dev Tools - Selecting the iFrame

How to add a custom CA Root certificate to the CA Store used by pip in Windows?

Open Anaconda Navigator.

Go to File\Preferences.

Enable SSL verification Disable (not recommended)

or Enable and indicate SSL certificate path(Optional)

Update a package to a specific version:

Select Install on Top-Right

Select package click on tick

Mark for update

Mark for specific version installation

Click Apply

How to Alter Constraint

You can not alter constraints ever but you can drop them and then recreate.

Have look on this

ALTER TABLE your_table DROP CONSTRAINT ACTIVEPROG_FKEY1;

and then recreate it with ON DELETE CASCADE like this

ALTER TABLE your_table
add CONSTRAINT ACTIVEPROG_FKEY1 FOREIGN KEY(ActiveProgCode) REFERENCES PROGRAM(ActiveProgCode)
    ON DELETE CASCADE;

hope this help

Alternate table with new not null Column in existing table in SQL

The easiest way to do this is :

ALTER TABLE db.TABLENAME ADD COLUMN [datatype] NOT NULL DEFAULT 'value'

Ex : Adding a column x (bit datatype) to a table ABC with default value 0

ALTER TABLE db.ABC ADD COLUMN x bit NOT NULL DEFAULT 0

PS : I am not a big fan of using the table designer for this. Its so much easier being conventional / old fashioned sometimes. :). Hope this helps answer

rails 3 validation on uniqueness on multiple attributes

In Rails 2, I would have written:

validates_uniqueness_of :zipcode, :scope => :recorded_at

In Rails 3:

validates :zipcode, :uniqueness => {:scope => :recorded_at}

For multiple attributes:

validates :zipcode, :uniqueness => {:scope => [:recorded_at, :something_else]}

UITextField text change event

Swift 3 Version

yourTextField.addTarget(self, action: #selector(YourControllerName.textChanges(_:)), for: UIControlEvents.editingChanged)

And get the changes in here

func textChanges(_ textField: UITextField) {
    let text = textField.text! // your desired text here
    // Now do whatever you want.
}

Hope it helps.

How to scroll to top of a div using jQuery?

I don't know why but you have to add a setTimeout with at least for me 200ms:

setTimeout( function() {$("#DIV_ID").scrollTop(0)}, 200 );

Tested with Firefox / Chrome / Edge.

CREATE FILE encountered operating system error 5(failed to retrieve text for this error. Reason: 15105)

I had this issue on Windows 2003 with SQL 2005. I had to take ownership of the files as my Windows user account and I got the database to attache that way.

You have to right click on the file, select Properties, click OK to get past the information screen, click the Advanced button, select your account from the listing of available accounts or groups, apply that change, and Click OK on the Properties screen. Once you have done all that you will be able to manage the file permissions.

I logged into SSMS with Windows Authentication and I was able to attach the database without error.

Cheers!

Button Listener for button in fragment in android

Use your code

public class FragmentOne extends Fragment implements OnClickListener{

    View view;
    Fragment fragmentTwo;
    FragmentManager fragmentManager = getFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment_one, container, false);
        Button buttonSayHi = (Button) view.findViewById(R.id.buttonSayHi);
        buttonSayHi.setOnClickListener(this);
        return view;
    }

But I think is better handle the buttons in this way:

@Override
    public void onClick(View v) {
        switch(v.getId()){
            case R.id.buttonSayHi:
            /** Do things you need to..
               fragmentTwo = new FragmentTwo();

               fragmentTransaction.replace(R.id.frameLayoutFragmentContainer, fragmentTwo);
               fragmentTransaction.addToBackStack(null);

               fragmentTransaction.commit();  
            */
            break;
        }   
    }

Download and open PDF file using Ajax

This is how i solve this issue.
The answer of Jonathan Amend on this post helped me a lot.
The example below is simplified.

For more details, the above source code is able to download a file using a JQuery Ajax request (GET, POST, PUT etc). It, also, helps to upload parameters as JSON and to change the content type to application/json (my default).

The html source:

<form method="POST">
    <input type="text" name="startDate"/>
    <input type="text" name="endDate"/>
    <input type="text" name="startDate"/>
    <select name="reportTimeDetail">
        <option value="1">1</option>
    </select>
    <button type="submit"> Submit</button>
</form>  

A simple form with two input text, one select and a button element.

The javascript page source:

<script type="text/javascript" src="JQuery 1.11.0 link"></script>
<script type="text/javascript">
    // File Download on form submition.
    $(document).on("ready", function(){
        $("form button").on("click", function (event) {
            event.stopPropagation(); // Do not propagate the event.

            // Create an object that will manage to download the file.
            new AjaxDownloadFile({
                url: "url that returns a file",
                data: JSON.stringify($("form").serializeObject())
            });

            return false; // Do not submit the form.
        });
    });
</script>  

A simple event on button click. It creates an AjaxDownloadFile object. The AjaxDownloadFile class source is below.

The AjaxDownloadFile class source:

var AjaxDownloadFile = function (configurationSettings) {
    // Standard settings.
    this.settings = {
        // JQuery AJAX default attributes.
        url: "",
        type: "POST",
        headers: {
            "Content-Type": "application/json; charset=UTF-8"
        },
        data: {},
        // Custom events.
        onSuccessStart: function (response, status, xhr, self) {
        },
        onSuccessFinish: function (response, status, xhr, self, filename) {
        },
        onErrorOccured: function (response, status, xhr, self) {
        }
    };
    this.download = function () {
        var self = this;
        $.ajax({
            type: this.settings.type,
            url: this.settings.url,
            headers: this.settings.headers,
            data: this.settings.data,
            success: function (response, status, xhr) {
                // Start custom event.
                self.settings.onSuccessStart(response, status, xhr, self);

                // Check if a filename is existing on the response headers.
                var filename = "";
                var disposition = xhr.getResponseHeader("Content-Disposition");
                if (disposition && disposition.indexOf("attachment") !== -1) {
                    var filenameRegex = /filename[^;=\n]*=(([""]).*?\2|[^;\n]*)/;
                    var matches = filenameRegex.exec(disposition);
                    if (matches != null && matches[1])
                        filename = matches[1].replace(/[""]/g, "");
                }

                var type = xhr.getResponseHeader("Content-Type");
                var blob = new Blob([response], {type: type});

                if (typeof window.navigator.msSaveBlob !== "undefined") {
                    // IE workaround for "HTML7007: One or more blob URLs were revoked by closing the blob for which they were created. These URLs will no longer resolve as the data backing the URL has been freed.
                    window.navigator.msSaveBlob(blob, filename);
                } else {
                    var URL = window.URL || window.webkitURL;
                    var downloadUrl = URL.createObjectURL(blob);

                    if (filename) {
                        // Use HTML5 a[download] attribute to specify filename.
                        var a = document.createElement("a");
                        // Safari doesn"t support this yet.
                        if (typeof a.download === "undefined") {
                            window.location = downloadUrl;
                        } else {
                            a.href = downloadUrl;
                            a.download = filename;
                            document.body.appendChild(a);
                            a.click();
                        }
                    } else {
                        window.location = downloadUrl;
                    }

                    setTimeout(function () {
                        URL.revokeObjectURL(downloadUrl);
                    }, 100); // Cleanup
                }

                // Final custom event.
                self.settings.onSuccessFinish(response, status, xhr, self, filename);
            },
            error: function (response, status, xhr) {
                // Custom event to handle the error.
                self.settings.onErrorOccured(response, status, xhr, self);
            }
        });
    };
    // Constructor.
    {
        // Merge settings.
        $.extend(this.settings, configurationSettings);
        // Make the request.
        this.download();
    }
};

I created this class to added to my JS library. It is reusable. Hope that helps.

#1045 - Access denied for user 'root'@'localhost' (using password: YES)

Try the following code:

$cfg['Servers'][$i]['password'] = '';

if you see Password column field as 'No' for the 'root' user in Users Overview page of phpMyAdmin.

Get value from JToken that may not exist (best practices)

TYPE variable = jsonbody["key"]?.Value<TYPE>() ?? DEFAULT_VALUE;

e.g.

bool attachMap = jsonbody["map"]?.Value<bool>() ?? false;

How can I serve static html from spring boot?

I am using :: Spring Boot :: (v2.0.4.RELEASE) with Spring Framework 5

Spring Boot 2.0 requires Java 8 as a minimum version. Many existing APIs have been updated to take advantage of Java 8 features such as: default methods on interfaces, functional callbacks, and new APIs such as javax.time.

Static Content

By default, Spring Boot serves static content from a directory called /static (or /public or /resources or /META-INF/resources) in the classpath or from the root of the ServletContext. It uses the ResourceHttpRequestHandler from Spring MVC so that you can modify that behavior by adding your own WebMvcConfigurer and overriding the addResourceHandlers method.

By default, resources are mapped on /** and located on /static directory. But you can customize the static loactions programmatically inside our web context configuration class.

@Configuration @EnableWebMvc
public class Static_ResourceHandler implements WebMvcConfigurer {

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        // When overriding default behavior, you need to add default(/) as well as added static paths(/webapp).

        // src/main/resources/static/...
        registry
            //.addResourceHandler("/**") // « /css/myStatic.css
            .addResourceHandler("/static/**") // « /static/css/myStatic.css
            .addResourceLocations("classpath:/static/") // Default Static Loaction
            .setCachePeriod( 3600 )
            .resourceChain(true) // 4.1
            .addResolver(new GzipResourceResolver()) // 4.1
            .addResolver(new PathResourceResolver()); //4.1

        // src/main/resources/templates/static/...
        registry
            .addResourceHandler("/templates/**") // « /templates/style.css
            .addResourceLocations("classpath:/templates/static/");

        // Do not use the src/main/webapp/... directory if your application is packaged as a jar.
        registry
            .addResourceHandler("/webapp/**") // « /webapp/css/style.css
            .addResourceLocations("/");

        // File located on disk
        registry
            .addResourceHandler("/system/files/**")
            .addResourceLocations("file:///D:/");
    }
}
http://localhost:8080/handlerPath/resource-path+name
                    /static         /css/myStatic.css
                    /webapp         /css/style.css
                    /templates      /style.css

In Spring every request will go through the DispatcherServlet. To avoid Static file request through DispatcherServlet(Front contoller) we configure MVC Static content.

As @STEEL said static resources should not go through Controller. Thymleaf is a ViewResolver which takes the view name form controller and adds prefix and suffix to View Layer.

How to check if a string contains an element from a list in Python

It is better to parse the URL properly - this way you can handle http://.../file.doc?foo and http://.../foo.doc/file.exe correctly.

from urlparse import urlparse
import os
path = urlparse(url_string).path
ext = os.path.splitext(path)[1]
if ext in extensionsToCheck:
  print(url_string)

Get mouse wheel events in jQuery?

This worked for me:)

 //Firefox
 $('#elem').bind('DOMMouseScroll', function(e){
     if(e.originalEvent.detail > 0) {
         //scroll down
         console.log('Down');
     }else {
         //scroll up
         console.log('Up');
     }

     //prevent page fom scrolling
     return false;
 });

 //IE, Opera, Safari
 $('#elem').bind('mousewheel', function(e){
     if(e.originalEvent.wheelDelta < 0) {
         //scroll down
         console.log('Down');
     }else {
         //scroll up
         console.log('Up');
     }

     //prevent page fom scrolling
     return false;
 });

from stackoverflow

cordova run with ios error .. Error code 65 for command: xcodebuild with args:

I must add :

I had the same problem, it was coming from the fact that my teammate had a different version of cordova, and commited plugins on the repo with his version.

For all cordova plugins, I had to :

cordova plugin rm <plugin-name> 
cordova plugin add <plugin-name>

And ask my teammate to update his cordova to match my version

Eclipse C++ : "Program "g++" not found in PATH"

You need:

C:\cygnus\cygwin-b20\H-i586-cygwin32\bin

in the PATH.

and not

C:\cygnus\cygwin-b20\H-i586-cygwin32\bin\g++

as you wrote.

Why is Ant giving me a Unsupported major.minor version error

One possible cause of this is an incorrect JRE selected in the Ant build options. After right-clicking the build.xml and choosing 'Run As...' and then 'Ant Build...', make sure the correct JRE is chosen under the JRE Tab of the configuration options dialogue box. You will see a 'Separate JRE' option; make sure the appropriate jdk is chosen from the drop down before clicking 'Run'.

What are 'get' and 'set' in Swift?

The getting and setting of variables within classes refers to either retrieving ("getting") or altering ("setting") their contents.

Consider a variable members of a class family. Naturally, this variable would need to be an integer, since a family can never consist of two point something people.

So you would probably go ahead by defining the members variable like this:

class family {
   var members:Int
}

This, however, will give people using this class the possibility to set the number of family members to something like 0 or 1. And since there is no such thing as a family of 1 or 0, this is quite unfortunate.

This is where the getters and setters come in. This way you can decide for yourself how variables can be altered and what values they can receive, as well as deciding what content they return.

Returning to our family class, let's make sure nobody can set the members value to anything less than 2:

class family {
  var _members:Int = 2
  var members:Int {
   get {
     return _members
   }
   set (newVal) {
     if newVal >= 2 {
       _members = newVal
     } else {
       println('error: cannot have family with less than 2 members')
     }
   }
  }
}

Now we can access the members variable as before, by typing instanceOfFamily.members, and thanks to the setter function, we can also set it's value as before, by typing, for example: instanceOfFamily.members = 3. What has changed, however, is the fact that we cannot set this variable to anything smaller than 2 anymore.

Note the introduction of the _members variable, which is the actual variable to store the value that we set through the members setter function. The original members has now become a computed property, meaning that it only acts as an interface to deal with our actual variable.

Wait Until File Is Completely Written

When the file is writing in binary(byte by byte),create FileStream and above solutions Not working,because file is ready and wrotted in every bytes,so in this Situation you need other workaround like this: Do this when file created or you want to start processing on file

long fileSize = 0;
currentFile = new FileInfo(path);

while (fileSize < currentFile.Length)//check size is stable or increased
{
  fileSize = currentFile.Length;//get current size
  System.Threading.Thread.Sleep(500);//wait a moment for processing copy
  currentFile.Refresh();//refresh length value
}

//Now file is ready for any process!

How to change button color with tkinter

When you do self.button = Button(...).grid(...), what gets assigned to self.button is the result of the grid() command, not a reference to the Button object created.

You need to assign your self.button variable before packing/griding it. It should look something like this:

self.button = Button(self,text="Click Me",command=self.color_change,bg="blue")
self.button.grid(row = 2, column = 2, sticky = W)

Copy Data from a table in one Database to another separate database

SELECT ... INTO creates a new table. You'll need to use INSERT. Also, you have the database and owner names reversed.

INSERT INTO DB1.dbo.TempTable
SELECT * FROM DB2.dbo.TempTable

Get current AUTO_INCREMENT value for any table

Even though methai's answer is correct if you manually run the query, a problem occurs when 2 concurrent transaction/connections actually execute this query at runtime in production (for instance).

Just tried manually in MySQL workbench with 2 connections opened simultaneously:

CREATE TABLE translation (
  id BIGINT PRIMARY KEY AUTO_INCREMENT
);
# Suppose we have already 20 entries, we execute 2 new inserts:

Transaction 1:

21 = SELECT `AUTO_INCREMENT` FROM INFORMATION_SCHEMA.TABLES
     WHERE TABLE_SCHEMA = 'DatabaseName' AND TABLE_NAME = 'translation';

insert into translation (id) values (21);

Transaction 2:

21 = SELECT `AUTO_INCREMENT` FROM INFORMATION_SCHEMA.TABLES
     WHERE TABLE_SCHEMA = 'DatabaseName' AND TABLE_NAME = 'translation';

insert into translation (id) values (21);

# commit transaction 1;
# commit transaction 2;

Insert of transaction 1 is ok: Insert of transaction 2 goes in error: Error Code: 1062. Duplicate entry '21' for key 'PRIMARY'.

A good solution would be jvdub's answer because per transaction/connection the 2 inserts will be:

Transaction 1:

insert into translation (id) values (null);
21 = SELECT LAST_INSERT_ID();

Transaction 2:

insert into translation (id) values (null);
22 = SELECT LAST_INSERT_ID();

# commit transaction 1;
# commit transaction 2;

But we have to execute the last_insert_id() just after the insert! And we can reuse that id to be inserted in others tables where a foreign key is expected!

Also, we cannot execute the 2 queries as following:

insert into translation (id) values ((SELECT AUTO_INCREMENT FROM
    information_schema.TABLES WHERE TABLE_SCHEMA=DATABASE()
    AND TABLE_NAME='translation'));

because we actually are interested to grab/reuse that ID in other table or to return!

HTML Button : Navigate to Other Page - Different Approaches

I make a link. A link is a link. A link navigates to another page. That is what links are for and everybody understands that. So Method 3 is the only correct method in my book.

I wouldn't want my link to look like a button at all, and when I do, I still think functionality is more important than looks.

Buttons are less accessible, not only due to the need of Javascript, but also because tools for the visually impaired may not understand this Javascript enhanced button well.

Method 4 would work as well, but it is more a trick than a real functionality. You abuse a form to post 'nothing' to this other page. It's not clean.

Java8: HashMap<X, Y> to HashMap<X, Z> using Stream / Map-Reduce / Collector

Map<String, String> x;
Map<String, Integer> y =
    x.entrySet().stream()
        .collect(Collectors.toMap(
            e -> e.getKey(),
            e -> Integer.parseInt(e.getValue())
        ));

It's not quite as nice as the list code. You can't construct new Map.Entrys in a map() call so the work is mixed into the collect() call.

SELECT list is not in GROUP BY clause and contains nonaggregated column .... incompatible with sql_mode=only_full_group_by

Hi instead of taking all columns, just take what you need by using ANY_VALUE(column_name). It is working perfectly. Just check.

E.g.:

SELECT proof_type,any_value("customer_name") as customer_name
FROM `tbl_customer_pod_uploads`
WHERE `load_id` = '78' AND `status` = 'Active' GROUP BY `proof_type`

ExecuteReader requires an open and available Connection. The connection's current state is Connecting

Sorry for only commenting in the first place, but i'm posting almost every day a similar comment since many people think that it would be smart to encapsulate ADO.NET functionality into a DB-Class(me too 10 years ago). Mostly they decide to use static/shared objects since it seems to be faster than to create a new object for any action.

That is neither a good idea in terms of peformance nor in terms of fail-safety.

Don't poach on the Connection-Pool's territory

There's a good reason why ADO.NET internally manages the underlying Connections to the DBMS in the ADO-NET Connection-Pool:

In practice, most applications use only one or a few different configurations for connections. This means that during application execution, many identical connections will be repeatedly opened and closed. To minimize the cost of opening connections, ADO.NET uses an optimization technique called connection pooling.

Connection pooling reduces the number of times that new connections must be opened. The pooler maintains ownership of the physical connection. It manages connections by keeping alive a set of active connections for each given connection configuration. Whenever a user calls Open on a connection, the pooler looks for an available connection in the pool. If a pooled connection is available, it returns it to the caller instead of opening a new connection. When the application calls Close on the connection, the pooler returns it to the pooled set of active connections instead of closing it. Once the connection is returned to the pool, it is ready to be reused on the next Open call.

So obviously there's no reason to avoid creating,opening or closing connections since actually they aren't created,opened and closed at all. This is "only" a flag for the connection pool to know when a connection can be reused or not. But it's a very important flag, because if a connection is "in use"(the connection pool assumes), a new physical connection must be openend to the DBMS what is very expensive.

So you're gaining no performance improvement but the opposite. If the maximum pool size specified (100 is the default) is reached, you would even get exceptions(too many open connections ...). So this will not only impact the performance tremendously but also be a source for nasty errors and (without using Transactions) a data-dumping-area.

If you're even using static connections you're creating a lock for every thread trying to access this object. ASP.NET is a multithreading environment by nature. So theres a great chance for these locks which causes performance issues at best. Actually sooner or later you'll get many different exceptions(like your ExecuteReader requires an open and available Connection).

Conclusion:

  • Don't reuse connections or any ADO.NET objects at all.
  • Don't make them static/shared(in VB.NET)
  • Always create, open(in case of Connections), use, close and dispose them where you need them(f.e. in a method)
  • use the using-statement to dispose and close(in case of Connections) implicitely

That's true not only for Connections(although most noticable). Every object implementing IDisposable should be disposed(simplest by using-statement), all the more in the System.Data.SqlClient namespace.

All the above speaks against a custom DB-Class which encapsulates and reuse all objects. That's the reason why i commented to trash it. That's only a problem source.


Edit: Here's a possible implementation of your retrievePromotion-method:

public Promotion retrievePromotion(int promotionID)
{
    Promotion promo = null;
    var connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["MainConnStr"].ConnectionString;
    using (SqlConnection connection = new SqlConnection(connectionString))
    {
        var queryString = "SELECT PromotionID, PromotionTitle, PromotionURL FROM Promotion WHERE PromotionID=@PromotionID";
        using (var da = new SqlDataAdapter(queryString, connection))
        {
            // you could also use a SqlDataReader instead
            // note that a DataTable does not need to be disposed since it does not implement IDisposable
            var tblPromotion = new DataTable();
            // avoid SQL-Injection
            da.SelectCommand.Parameters.Add("@PromotionID", SqlDbType.Int);
            da.SelectCommand.Parameters["@PromotionID"].Value = promotionID;
            try
            {
                connection.Open(); // not necessarily needed in this case because DataAdapter.Fill does it otherwise 
                da.Fill(tblPromotion);
                if (tblPromotion.Rows.Count != 0)
                {
                    var promoRow = tblPromotion.Rows[0];
                    promo = new Promotion()
                    {
                        promotionID    = promotionID,
                        promotionTitle = promoRow.Field<String>("PromotionTitle"),
                        promotionUrl   = promoRow.Field<String>("PromotionURL")
                    };
                }
            }
            catch (Exception ex)
            {
                // log this exception or throw it up the StackTrace
                // we do not need a finally-block to close the connection since it will be closed implicitely in an using-statement
                throw;
            }
        }
    }
    return promo;
}

Scrolling a div with jQuery

Relatively-position your content div within a parent div having overflow:hidden. Make your up/down arrows move the top value of the content div. The following jQuery is untested. Let me know if you require any further assistance with it as a concept.

div.container {
  overflow:hidden;
  width:200px;
  height:200px;
}
div.content {
  position:relative;
  top:0;
}

<div class="container">
  <p>
    <a href="enablejs.html" class="up">Up</a> / 
    <a href="enablejs.html" class="dn">Down</a>
  </p>
  <div class="content">
    <p>Hello World</p>
  </div>
</div>

$(function(){
  $(".container a.up").bind("click", function(){
    var topVal = $(this).parents(".container").find(".content").css("top");
    $(this).parents(".container").find(".content").css("top", topVal-10);
  });

  $(".container a.dn").bind("click", function(){
    var topVal = $(this).parents(".container").find(".content").css("top");
    $(this).parents(".container").find(".content").css("top", topVal+10);
  });
});

text flowing out of div

Use

white-space: pre-line;

It will prevent text from flowing out of the div. It will break the text as it reaches the end of the div.

What is a stack trace, and how can I use it to debug my application errors?

Just to add to the other examples, there are inner(nested) classes that appear with the $ sign. For example:

public class Test {

    private static void privateMethod() {
        throw new RuntimeException();
    }

    public static void main(String[] args) throws Exception {
        Runnable runnable = new Runnable() {
            @Override public void run() {
                privateMethod();
            }
        };
        runnable.run();
    }
}

Will result in this stack trace:

Exception in thread "main" java.lang.RuntimeException
        at Test.privateMethod(Test.java:4)
        at Test.access$000(Test.java:1)
        at Test$1.run(Test.java:10)
        at Test.main(Test.java:13)

In jQuery how can I set "top,left" properties of an element with position values relative to the parent and not the document?

You could try jQuery UI's .position method.

$("#mydiv").position({
  of: $('#mydiv').parent(),
  my: 'left+200 top+200',
  at: 'left top'
});

Check the working demo.

How can I hash a password in Java?

While the NIST recommendation PBKDF2 has already been mentioned, I'd like to point out that there was a public password hashing competition that ran from 2013 to 2015. In the end, Argon2 was chosen as the recommended password hashing function.

There is a fairly well adopted Java binding for the original (native C) library that you can use.

In the average use-case, I don't think it does matter from a security perspective if you choose PBKDF2 over Argon2 or vice-versa. If you have strong security requirements, I recommend considering Argon2 in your evaluation.

For further information on the security of password hashing functions see security.se.

python filter list of dictionaries based on key value

Use filter, or if the number of dictionaries in exampleSet is too high, use ifilter of the itertools module. It would return an iterator, instead of filling up your system's memory with the entire list at once:

from itertools import ifilter
for elem in ifilter(lambda x: x['type'] in keyValList, exampleSet):
    print elem

What is the "right" JSON date format?

The following code has worked for me. This code will print date in DD-MM-YYYY format.

DateValue=DateValue.substring(6,8)+"-"+DateValue.substring(4,6)+"-"+DateValue.substring(0,4);

else, you can also use:

DateValue=DateValue.substring(0,4)+"-"+DateValue.substring(4,6)+"-"+DateValue.substring(6,8);

android adb turn on wifi via adb

I was in the same situation on a Samsung Mini II. I got around it eventually by holding down the power button until the "power off" menu appeared. From this menu it was possible to enable the network data connection.

Then signing in to my google account using @googlemail.com (rather than @gmail.com) seemed to do the trick. Though the change of address may just have given the phone time to warm up the 3g connection rather than making any real difference.

Java SSL: how to disable hostname verification

It should be possible to create custom java agent that overrides default HostnameVerifier:

import javax.net.ssl.*;
import java.lang.instrument.Instrumentation;

public class LenientHostnameVerifierAgent {
    public static void premain(String args, Instrumentation inst) {
        HttpsURLConnection.setDefaultHostnameVerifier(new HostnameVerifier() {
            public boolean verify(String s, SSLSession sslSession) {
                return true;
            }
        });
    }
}

Then just add -javaagent:LenientHostnameVerifierAgent.jar to program's java startup arguments.

pip install access denied on Windows

One additional thing that has not been covered in previous answers and that often cause issues on Windows and stopped me from installing some package despite running as admin is that you get the same permission denied error if there is another program that use some of the files you (or pip install) try to access. This is a really stupid "feature" of Windows that pops up many times, e.g. when trying to move some files.

In addition I have no clue how to figure out which program locks a particular file, so the easiest ting to do is to reboot and do the installation before starting anything, in particular before running e.g. Spyder or any other Python-based software. You can also try to close all programs, but it can be tricky to know which one actually holds a file. For a directory for example, it is enough that you have an Explorer window open at that directory.

How to align a div to the top of its parent but keeping its inline-block behaviour?

As others have said, vertical-align: top is your friend.

As a bonus here is a forked fiddle with added enhancements that make it work in Internet Explorer 6 and Internet Explorer 7 too ;)

Example: here

MongoDB: update every document on one field

Regardless of the version, for your example, the <update> is:

{  $set: { lastLookedAt: Date.now() / 1000 }  }

However, depending on your version of MongoDB, the query will look different. Regardless of version, the key is that the empty condition {} will match any document. In the Mongo shell, or with any MongoDB client:

$version >= 3.2:

db.foo.updateMany( {}, <update> )
  • {} is the condition (the empty condition matches any document)

3.2 > $version >= 2.2:

db.foo.update( {}, <update>, { multi: true } )
  • {} is the condition (the empty condition matches any document)
  • {multi: true} is the "update multiple documents" option

$version < 2.2:

db.foo.update( {}, <update>, false, true )
  • {} is the condition (the empty condition matches any document)
  • false is for the "upsert" parameter
  • true is for the "multi" parameter (update multiple records)

How to split a python string on new line characters

a.txt

this is line 1
this is line 2

code:

Python 3.4.0 (default, Mar 20 2014, 22:43:40) 
[GCC 4.6.3] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> file = open('a.txt').read()
>>> file
>>> file.split('\n')
['this is line 1', 'this is line 2', '']

I'm on Linux, but I guess you just use \r\n on Windows and it would also work

Efficient SQL test query or validation query that will work across all (or most) databases

After a little bit of research along with help from some of the answers here:

SELECT 1

  • H2
  • MySQL
  • Microsoft SQL Server (according to NimChimpsky)
  • PostgreSQL
  • SQLite

SELECT 1 FROM DUAL

  • Oracle

SELECT 1 FROM any_existing_table WHERE 1=0

or

SELECT 1 FROM INFORMATION_SCHEMA.SYSTEM_USERS

or

CALL NOW()

  • HSQLDB (tested with version 1.8.0.10)

    Note: I tried using a WHERE 1=0 clause on the second query, but it didn't work as a value for Apache Commons DBCP's validationQuery, since the query doesn't return any rows


VALUES 1 or SELECT 1 FROM SYSIBM.SYSDUMMY1

SELECT 1 FROM SYSIBM.SYSDUMMY1

  • DB2

select count(*) from systables

  • Informix

Is it possible to make input fields read-only through CSS?

Hope this will help.

    input[readonly="readonly"]
{
    background-color:blue;
}

reference:

http://jsfiddle.net/uzyH5/1/

How can I get the last character in a string?

Use the charAt method. This function accepts one argument: The index of the character.

var lastCHar = myString.charAt(myString.length-1);

Failed to create provisioning profile

I have had this error multiple times and what solves it for me is the following:

  1. In the list with the view of all certificates, right click on each row and move each certificate to trash (go to Xcode > Preferences > Choose account > Click View Details)
  2. Go to member center download the right certificates again and click on them so
  3. Restart Xcode
  4. Go to build settings and set the right Code signing for debug/release - you should be able to see an option on the row that says "Identities from profile..."

If this doesn't work then you should consider revoking your certificate and then create a new one and the do the steps above again.

Jquery each - Stop loop and return object

Try this ...

  someArray = new Array();
  someArray[0] = 't5';
  someArray[1] = 'z12';
  someArray[2] = 'b88';
  someArray[3] = 's55';
  someArray[4] = 'e51';
  someArray[5] = 'o322';
  someArray[6] = 'i22';
  someArray[7] = 'k954';  

  var test =  findXX('o322'); 
  console.log(test);



function findXX(word)
{  
  for(var i in someArray){


    if(someArray[i] == word)
    {
      return someArray[i]; //<---  stop the loop!
    }   
  }
}

What is fastest children() or find() in jQuery?

Here is a link that has a performance test you can run. find() is actually about 2 times faster than children().

Chrome on OSX10.7.6

Custom fonts and XML layouts (Android)

I'm 3 years late for the party :( However this could be useful for someone who might stumble upon this post.

I've written a library that caches Typefaces and also allow you to specify custom typefaces right from XML. You can find the library here.

Here is how your XML layout would look like, when you use it.

<com.mobsandgeeks.ui.TypefaceTextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/hello_world"
    geekui:customTypeface="fonts/custom_font.ttf" />

How to communicate between Docker containers via "hostname"

That should be what --link is for, at least for the hostname part.
With docker 1.10, and PR 19242, that would be:

docker network create --net-alias=[]: Add network-scoped alias for the container

(see last section below)

That is what Updating the /etc/hosts file details

In addition to the environment variables, Docker adds a host entry for the source container to the /etc/hosts file.

For instance, launch an LDAP server:

docker run -t  --name openldap -d -p 389:389 larrycai/openldap

And define an image to test that LDAP server:

FROM ubuntu
RUN apt-get -y install ldap-utils
RUN touch /root/.bash_aliases
RUN echo "alias lds='ldapsearch -H ldap://internalopenldap -LL -b
ou=Users,dc=openstack,dc=org -D cn=admin,dc=openstack,dc=org -w
password'" > /root/.bash_aliases
ENTRYPOINT bash

You can expose the 'openldap' container as 'internalopenldap' within the test image with --link:

 docker run -it --rm --name ldp --link openldap:internalopenldap ldaptest

Then, if you type 'lds', that alias will work:

ldapsearch -H ldap://internalopenldap ...

That would return people. Meaning internalopenldap is correctly reached from the ldaptest image.


Of course, docker 1.7 will add libnetwork, which provides a native Go implementation for connecting containers. See the blog post.
It introduced a more complete architecture, with the Container Network Model (CNM)

https://blog.docker.com/media/2015/04/cnm-model.jpg

That will Update the Docker CLI with new “network” commands, and document how the “-net” flag is used to assign containers to networks.


docker 1.10 has a new section Network-scoped alias, now officially documented in network connect:

While links provide private name resolution that is localized within a container, the network-scoped alias provides a way for a container to be discovered by an alternate name by any other container within the scope of a particular network.
Unlike the link alias, which is defined by the consumer of a service, the network-scoped alias is defined by the container that is offering the service to the network.

Continuing with the above example, create another container in isolated_nw with a network alias.

$ docker run --net=isolated_nw -itd --name=container6 -alias app busybox
8ebe6767c1e0361f27433090060b33200aac054a68476c3be87ef4005eb1df17

--alias=[]         

Add network-scoped alias for the container

You can use --link option to link another container with a preferred alias

You can pause, restart, and stop containers that are connected to a network. Paused containers remain connected and can be revealed by a network inspect. When the container is stopped, it does not appear on the network until you restart it.

If specified, the container's IP address(es) is reapplied when a stopped container is restarted. If the IP address is no longer available, the container fails to start.

One way to guarantee that the IP address is available is to specify an --ip-range when creating the network, and choose the static IP address(es) from outside that range. This ensures that the IP address is not given to another container while this container is not on the network.

$ docker network create --subnet 172.20.0.0/16 --ip-range 172.20.240.0/20 multi-host-network

$ docker network connect --ip 172.20.128.2 multi-host-network container2
$ docker network connect --link container1:c1 multi-host-network container2

Div 100% height works on Firefox but not in IE

I don't think IE supports the use of auto for setting height / width, so you could try giving this a numeric value (like Jarett suggests).

Also, it doesn't look like you are clearing your floats properly. Try adding this to your CSS for #container:

#container {
    height:100%;
    width:100%;
    overflow:hidden;
    /* for IE */
    zoom:1;
}

How to make a 3-level collapsing menu in Bootstrap?

Bootstrap 3 dropped native support for nested collapsing menus, but there's a way to re-enable it with a 3rd party script. It's called SmartMenus. It means adding three new resources to your page, but it seamlessly supports Bootstrap 3.x with multiple levels of menus for nested <ul>/<li> elements with class="dropdown-menu". It automatically displays the proper caret indicator as well.

<head>
   ...
   <script src=".../jquery.smartmenus.min.js"></script>
   <script src=".../jquery.smartmenus.bootstrap.min.js"></script>
   ...
   <link rel="stylesheet" href=".../jquery.smartmenus.bootstrap.min.css"/>
   ...
</head>

Here's a demo page: http://vadikom.github.io/smartmenus/src/demo/bootstrap-navbar-fixed-top.html

class method generates "TypeError: ... got multiple values for keyword argument ..."

The problem is that the first argument passed to class methods in python is always a copy of the class instance on which the method is called, typically labelled self. If the class is declared thus:

class foo(object):
  def foodo(self, thing=None, thong='not underwear'):
    print thing if thing else "nothing" 
    print 'a thong is',thong

it behaves as expected.

Explanation:

Without self as the first parameter, when myfoo.foodo(thing="something") is executed, the foodo method is called with arguments (myfoo, thing="something"). The instance myfoo is then assigned to thing (since thing is the first declared parameter), but python also attempts to assign "something" to thing, hence the Exception.

To demonstrate, try running this with the original code:

myfoo.foodo("something")
print
print myfoo

You'll output like:

<__main__.foo object at 0x321c290>
a thong is something

<__main__.foo object at 0x321c290>

You can see that 'thing' has been assigned a reference to the instance 'myfoo' of the class 'foo'. This section of the docs explains how function arguments work a bit more.

Call another rest api from my server in Spring-Boot

Modern Spring 5+ answer using WebClient instead of RestTemplate.

Configure WebClient for a specific web-service or resource as a bean (additional properties can be configured).

@Bean
public WebClient localApiClient() {
    return WebClient.create("http://localhost:8080/api/v3");
}

Inject and use the bean from your service(s).

@Service
public class UserService {

    private static final Duration REQUEST_TIMEOUT = Duration.ofSeconds(3);

    private final WebClient localApiClient;

    @Autowired
    public UserService(WebClient localApiClient) {
        this.localApiClient = localApiClient;
    }

    public User getUser(long id) {
        return localApiClient
                .get()
                .uri("/users/" + id)
                .retrieve()
                .bodyToMono(User.class)
                .block(REQUEST_TIMEOUT);
    }

}

Using request.setAttribute in a JSP page

If you want your requests to persists try this:

example: on your JSP or servlet page

request.getSession().setAttribute("SUBFAMILY", subFam);

and on any receiving page use the below lines to retrieve your session and data:

SubFamily subFam = (SubFamily)request.getSession().getAttribute("SUBFAMILY");

How to include duplicate keys in HashMap?

hashMaps can't have duplicate keys. That said, you can create a map with list values:

Map<Integer, List<String>>

However, using this approach will have performance implications.

Embed HTML5 YouTube video without iframe?

Yes. Youtube API is the best resource for this.

There are 3 way to embed a video:

  • IFrame embeds using <iframe> tags
  • IFrame embeds using the IFrame Player API
  • AS3 (and AS2*) object embeds DEPRECATED

I think you are looking for the second one of them:

IFrame embeds using the IFrame Player API

The HTML and JavaScript code below shows a simple example that inserts a YouTube player into the page element that has an id value of ytplayer. The onYouTubePlayerAPIReady() function specified here is called automatically when the IFrame Player API code has loaded. This code does not define any player parameters and also does not define other event handlers.

<div id="ytplayer"></div>

<script>
  // Load the IFrame Player API code asynchronously.
  var tag = document.createElement('script');
  tag.src = "https://www.youtube.com/player_api";
  var firstScriptTag = document.getElementsByTagName('script')[0];
  firstScriptTag.parentNode.insertBefore(tag, firstScriptTag);

  // Replace the 'ytplayer' element with an <iframe> and
  // YouTube player after the API code downloads.
  var player;
  function onYouTubePlayerAPIReady() {
    player = new YT.Player('ytplayer', {
      height: '390',
      width: '640',
      videoId: 'M7lc1UVf-VE'
    });
  }
</script>

Here are some instructions where you may take a look when starting using the API.


An embed example without using iframe is to use <object> tag:

<object width="640" height="360">
    <param name="movie" value="http://www.youtube.com/embed/yt-video-id?html5=1&amp;rel=0&amp;hl=en_US&amp;version=3"/
    <param name="allowFullScreen" value="true"/>
    <param name="allowscriptaccess" value="always"/>
    <embed width="640" height="360" src="http://www.youtube.com/embed/yt-video-id?html5=1&amp;rel=0&amp;hl=en_US&amp;version=3" class="youtube-player" type="text/html" allowscriptaccess="always" allowfullscreen="true"/>
</object>

(replace yt-video-id with your video id)

JSFIDDLE

Change font-weight of FontAwesome icons?

Webkit browsers support the ability to add "stroke" to fonts. This bit of style makes fonts look thinner (assuming a white background):

-webkit-text-stroke: 2px white;

Example on codepen here: http://codepen.io/mackdoyle/pen/yrgEH Some people are using SVG for a cross-platform "stroke" solution: http://codepen.io/CrocoDillon/pen/dGIsK

Search a string in a file and delete it from this file by Shell Script

This should do it:

sed -e s/deletethis//g -i *
sed -e "s/deletethis//g" -i.backup *
sed -e "s/deletethis//g" -i .backup *

it will replace all occurrences of "deletethis" with "" (nothing) in all files (*), editing them in place.

In the second form the pattern can be edited a little safer, and it makes backups of any modified files, by suffixing them with ".backup".

The third form is the way some versions of sed like it. (e.g. Mac OS X)

man sed for more information.

Identify if a string is a number

If you want to know if a string is a number, you could always try parsing it:

var numberString = "123";
int number;

int.TryParse(numberString , out number);

Note that TryParse returns a bool, which you can use to check if your parsing succeeded.

Is the buildSessionFactory() Configuration method deprecated in Hibernate

here are many APIs deprecated in the hibernate core framework.

we have created the session factory as below:

SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();

The method buildSessionFactory is deprecated from the hibernate 4 release and it is replaced with the new API. If you are using the hibernate 4.3.0 and above, your code has to be:

  1. Configuration configuration = new Configuration().configure();

  2. StandardServiceRegistryBuilder builder = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties());

  3. SessionFactory factory = configuration.buildSessionFactory(builder.build());

Class ServiceRegistryBuilder is replaced by StandardServiceRegistryBuilder from 4.3.0. It looks like there will be lot of changes in the 5.0 release. Still there is not much clarity on the deprecated APIs and the suitable alternatives to use. Every incremental release comes up with more deprecated API, they are in way of fine tuning the core framework for the release 5.0.

iOS 7 - Status bar overlaps the view

Vincent's answer edgesForExtendedLayout worked for me.

These macros help in determining os version making it easier

// 7.0 and above 
#define IS_DEVICE_RUNNING_IOS_7_AND_ABOVE() ([[[UIDevice currentDevice] systemVersion] compare:@"7.0" options:NSNumericSearch] != NSOrderedAscending) 

// 6.0, 6.0.x, 6.1, 6.1.x
#define IS_DEVICE_RUNNING_IOS_6_OR_BELOW() ([[[UIDevice currentDevice] systemVersion] compare:@"6.2" options:NSNumericSearch] != NSOrderedDescending) 

add these macros to prefix.pch file of your project and can be accessed anywhere

if(IS_DEVICE_RUNNING_IOS_7_AND_ABOVE())
{
 //some iOS 7 stuff
 self.edgesForExtendedLayout = UIRectEdgeNone;
}

if(IS_DEVICE_RUNNING_IOS_6_OR_BELOW())
{
 // some old iOS stuff
}

Swift Alamofire: How to get the HTTP response status code

you may check the following code for status code handler by alamofire

    let request = URLRequest(url: URL(string:"url string")!)    
    Alamofire.request(request).validate(statusCode: 200..<300).responseJSON { (response) in
        switch response.result {
        case .success(let data as [String:Any]):
            completion(true,data)
        case .failure(let err):
            print(err.localizedDescription)
            completion(false,err)
        default:
            completion(false,nil)
        }
    }

if status code is not validate it will be enter the failure in switch case

How to fix java.net.SocketException: Broken pipe?

This is caused by:

  • most usually, writing to a connection when the other end has already closed it;
  • less usually, the peer closing the connection without reading all the data that is already pending at his end.

So in both cases you have a poorly defined or implemented application protocol.

There is a third reason which I will not document here but which involves the peer taking deliberate action to reset rather than properly close the connection.

Creating a random string with A-Z and 0-9 in Java

You can easily do that with a for loop,

public static void main(String[] args) {
  String aToZ="ABCD.....1234"; // 36 letter.
  String randomStr=generateRandom(aToZ);

}

private static String generateRandom(String aToZ) {
    Random rand=new Random();
    StringBuilder res=new StringBuilder();
    for (int i = 0; i < 17; i++) {
       int randIndex=rand.nextInt(aToZ.length()); 
       res.append(aToZ.charAt(randIndex));            
    }
    return res.toString();
}

AngularJS : Initialize service with asynchronous data

You can use JSONP to asynchronously load service data. The JSONP request will be made during the initial page load and the results will be available before your application starts. This way you won't have to bloat your routing with redundant resolves.

You html would look like this:

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<script>

function MyService {
  this.getData = function(){
    return   MyService.data;
  }
}
MyService.setData = function(data) {
  MyService.data = data;
}

angular.module('main')
.service('MyService', MyService)

</script>
<script src="/some_data.php?jsonp=MyService.setData"></script>

How can I convert this foreach code to Parallel.ForEach?

Foreach loop:

  • Iterations takes place sequentially, one by one
  • foreach loop is run from a single Thread.
  • foreach loop is defined in every framework of .NET
  • Execution of slow processes can be slower, as they're run serially
    • Process 2 can't start until 1 is done. Process 3 can't start until 2 & 1 are done...
  • Execution of quick processes can be faster, as there is no threading overhead

Parallel.ForEach:

  • Execution takes place in parallel way.
  • Parallel.ForEach uses multiple Threads.
  • Parallel.ForEach is defined in .Net 4.0 and above frameworks.
  • Execution of slow processes can be faster, as they can be run in parallel
    • Processes 1, 2, & 3 may run concurrently (see reused threads in example, below)
  • Execution of quick processes can be slower, because of additional threading overhead

The following example clearly demonstrates the difference between traditional foreach loop and

Parallel.ForEach() Example

using System;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;
namespace ParallelForEachExample
{
    class Program
    {
        static void Main()
        {
            string[] colors = {
                                  "1. Red",
                                  "2. Green",
                                  "3. Blue",
                                  "4. Yellow",
                                  "5. White",
                                  "6. Black",
                                  "7. Violet",
                                  "8. Brown",
                                  "9. Orange",
                                  "10. Pink"
                              };
            Console.WriteLine("Traditional foreach loop\n");
            //start the stopwatch for "for" loop
            var sw = Stopwatch.StartNew();
            foreach (string color in colors)
            {
                Console.WriteLine("{0}, Thread Id= {1}", color, Thread.CurrentThread.ManagedThreadId);
                Thread.Sleep(10);
            }
            Console.WriteLine("foreach loop execution time = {0} seconds\n", sw.Elapsed.TotalSeconds);
            Console.WriteLine("Using Parallel.ForEach");
            //start the stopwatch for "Parallel.ForEach"
             sw = Stopwatch.StartNew();
            Parallel.ForEach(colors, color =>
            {
                Console.WriteLine("{0}, Thread Id= {1}", color, Thread.CurrentThread.ManagedThreadId);
                Thread.Sleep(10);
            }
            );
            Console.WriteLine("Parallel.ForEach() execution time = {0} seconds", sw.Elapsed.TotalSeconds);
            Console.Read();
        }
    }
}

Output

Traditional foreach loop
1. Red, Thread Id= 10
2. Green, Thread Id= 10
3. Blue, Thread Id= 10
4. Yellow, Thread Id= 10
5. White, Thread Id= 10
6. Black, Thread Id= 10
7. Violet, Thread Id= 10
8. Brown, Thread Id= 10
9. Orange, Thread Id= 10
10. Pink, Thread Id= 10
foreach loop execution time = 0.1054376 seconds

Using Parallel.ForEach example

1. Red, Thread Id= 10
3. Blue, Thread Id= 11
4. Yellow, Thread Id= 11
2. Green, Thread Id= 10
5. White, Thread Id= 12
7. Violet, Thread Id= 14
9. Orange, Thread Id= 13
6. Black, Thread Id= 11
8. Brown, Thread Id= 10
10. Pink, Thread Id= 12
Parallel.ForEach() execution time = 0.055976 seconds

Left join only selected columns in R with the merge() function

Nothing elegant but this could be another satisfactory answer.

merge(x = DF1, y = DF2, by = "Client", all.x=TRUE)[,c("Client","LO","CON")]

This will be useful especially when you don't need the keys that were used to join the tables in your results.

Regex allow a string to only contain numbers 0 - 9 and limit length to 45

A combination of both attempts is probably what you need:

^[0-9]{1,45}$

Most Pythonic way to provide global configuration variables in config.py?

please check out the IPython configuration system, implemented via traitlets for the type enforcement you are doing manually.

Cut and pasted here to comply with SO guidelines for not just dropping links as the content of links changes over time.

traitlets documentation

Here are the main requirements we wanted our configuration system to have:

Support for hierarchical configuration information.

Full integration with command line option parsers. Often, you want to read a configuration file, but then override some of the values with command line options. Our configuration system automates this process and allows each command line option to be linked to a particular attribute in the configuration hierarchy that it will override.

Configuration files that are themselves valid Python code. This accomplishes many things. First, it becomes possible to put logic in your configuration files that sets attributes based on your operating system, network setup, Python version, etc. Second, Python has a super simple syntax for accessing hierarchical data structures, namely regular attribute access (Foo.Bar.Bam.name). Third, using Python makes it easy for users to import configuration attributes from one configuration file to another. Fourth, even though Python is dynamically typed, it does have types that can be checked at runtime. Thus, a 1 in a config file is the integer ‘1’, while a '1' is a string.

A fully automated method for getting the configuration information to the classes that need it at runtime. Writing code that walks a configuration hierarchy to extract a particular attribute is painful. When you have complex configuration information with hundreds of attributes, this makes you want to cry.

Type checking and validation that doesn’t require the entire configuration hierarchy to be specified statically before runtime. Python is a very dynamic language and you don’t always know everything that needs to be configured when a program starts.

To acheive this they basically define 3 object classes and their relations to each other:

1) Configuration - basically a ChainMap / basic dict with some enhancements for merging.

2) Configurable - base class to subclass all things you'd wish to configure.

3) Application - object that is instantiated to perform a specific application function, or your main application for single purpose software.

In their words:

Application: Application

An application is a process that does a specific job. The most obvious application is the ipython command line program. Each application reads one or more configuration files and a single set of command line options and then produces a master configuration object for the application. This configuration object is then passed to the configurable objects that the application creates. These configurable objects implement the actual logic of the application and know how to configure themselves given the configuration object.

Applications always have a log attribute that is a configured Logger. This allows centralized logging configuration per-application. Configurable: Configurable

A configurable is a regular Python class that serves as a base class for all main classes in an application. The Configurable base class is lightweight and only does one things.

This Configurable is a subclass of HasTraits that knows how to configure itself. Class level traits with the metadata config=True become values that can be configured from the command line and configuration files.

Developers create Configurable subclasses that implement all of the logic in the application. Each of these subclasses has its own configuration information that controls how instances are created.

How to convert UTF-8 byte[] to string?

Converting a byte[] to a string seems simple but any kind of encoding is likely to mess up the output string. This little function just works without any unexpected results:

private string ToString(byte[] bytes)
{
    string response = string.Empty;

    foreach (byte b in bytes)
        response += (Char)b;

    return response;
}

@try - catch block in Objective-C

Objective-C is not Java. In Objective-C exceptions are what they are called. Exceptions! Don’t use them for error handling. It’s not their proposal. Just check the length of the string before using characterAtIndex and everything is fine....

Rounding SQL DateTime to midnight

In SQL Server 2008 and newer you can cast the DateTime to a Date, which removes the time element.

WHERE Orders.OrderStatus = 'Shipped'  
AND Orders.ShipDate >= (cast(GETDATE()-6 as date))  

In SQL Server 2005 and below you can use:

WHERE Orders.OrderStatus = 'Shipped'  
AND Orders.ShipDate >= DateAdd(Day, Datediff(Day,0, GetDate() -6), 0)

org.apache.catalina.LifecycleException: Failed to start component [StandardServer[8005]]A child container failed during start

Went through the various resources on the net but none of them helped then i deleted the existing server and added the same server again and now it is working fine and the steps are

Window>>ShowView>>Servers>>RightClick>>Delete

and then add the server again as you have added previously.

PHPMailer character encoding issues

The simplest way and will help you with is set CharSet to UTF-8

$mail->CharSet = "UTF-8"

Regex to validate date format dd/mm/yyyy

Notice:

Your regexp does not work for years that "are multiples of 4 and 100, but not of 400". Years that pass that test are not leap years. For example: 1900, 2100, 2200, 2300, 2500, etc. In other words, it puts all years with the format \d\d00 in the same class of leap years, which is incorrect. – MuchToLearn

So it works properly only for [1901 - 2099] (Whew)

dd/MM/yyyy:

Checks if leap year. Years from 1900 to 9999 are valid. Only dd/MM/yyyy

(^(((0[1-9]|1[0-9]|2[0-8])[\/](0[1-9]|1[012]))|((29|30|31)[\/](0[13578]|1[02]))|((29|30)[\/](0[4,6,9]|11)))[\/](19|[2-9][0-9])\d\d$)|(^29[\/]02[\/](19|[2-9][0-9])(00|04|08|12|16|20|24|28|32|36|40|44|48|52|56|60|64|68|72|76|80|84|88|92|96)$)

Catch a thread's exception in the caller thread in Python

pygolang provides sync.WorkGroup which, in particular, propagates exception from spawned worker threads to the main thread. For example:

#!/usr/bin/env python
"""This program demostrates how with sync.WorkGroup an exception raised in
spawned thread is propagated into main thread which spawned the worker."""

from __future__ import print_function
from golang import sync, context

def T1(ctx, *argv):
    print('T1: run ... %r' % (argv,))
    raise RuntimeError('T1: problem')

def T2(ctx):
    print('T2: ran ok')

def main():
    wg = sync.WorkGroup(context.background())
    wg.go(T1, [1,2,3])
    wg.go(T2)

    try:
        wg.wait()
    except Exception as e:
        print('Tmain: caught exception: %r\n' %e)
        # reraising to see full traceback
        raise

if __name__ == '__main__':
    main()

gives the following when run:

T1: run ... ([1, 2, 3],)
T2: ran ok
Tmain: caught exception: RuntimeError('T1: problem',)

Traceback (most recent call last):
  File "./x.py", line 28, in <module>
    main()
  File "./x.py", line 21, in main
    wg.wait()
  File "golang/_sync.pyx", line 198, in golang._sync.PyWorkGroup.wait
    pyerr_reraise(pyerr)
  File "golang/_sync.pyx", line 178, in golang._sync.PyWorkGroup.go.pyrunf
    f(pywg._pyctx, *argv, **kw)
  File "./x.py", line 10, in T1
    raise RuntimeError('T1: problem')
RuntimeError: T1: problem

The original code from the question would be just:

    wg = sync.WorkGroup(context.background())

    def _(ctx):
        shul.copytree(sourceFolder, destFolder)
    wg.go(_)

    # waits for spawned worker to complete and, on error, reraises
    # its exception on the main thread.
    wg.wait()

What is <scope> under <dependency> in pom.xml for?

.pom dependency scope can contain:

  • compile - available at Compile-time and Run-time
  • provided - available at Compile-time. (this dependency should be provided by outer container like OS...)
  • runtime - available at Run-time
  • test - test compilation and run time
  • system - is similar to provided but exposes <systemPath>path/some.jar</systemPath> to point on .jar
  • import - is available from Maven v2.0.9 for <type>pom</type> and it should be replaced by effective dependency from this file <dependencyManagement/>

jQuery attr('onclick')

As @Richard pointed out above, the onClick needs to have a capital 'C'.

$('#stop').click(function() {
     $('next').attr('onClick','stopMoving()');
}

WinError 2 The system cannot find the file specified (Python)

Popen expect a list of strings for non-shell calls and a string for shell calls.

Call subprocess.Popen with shell=True:

process = subprocess.Popen(command, stdout=tempFile, shell=True)

Hopefully this solves your issue.

This issue is listed here: https://bugs.python.org/issue17023

How to get info on sent PHP curl request

The request is printed in a request.txt with details

$ch = curl_init();
$f = fopen('request.txt', 'w');
curl_setopt_array($ch, array(
CURLOPT_URL            => $url, 
CURLOPT_RETURNTRANSFER => 1,
CURLOPT_FOLLOWLOCATION => 1,
CURLOPT_VERBOSE        => 1,
CURLOPT_STDERR         => $f,
));
$response = curl_exec($ch);
fclose($f);
curl_close($ch);

You can also use curl_getinfo() function.

Adding a newline character within a cell (CSV)

This question was answered well at Can you encode CR/LF in into CSV files?.

Consider also reverse engineering multiple lines in Excel. To embed a newline in an Excel cell, press Alt+Enter. Then save the file as a .csv. You'll see that the double-quotes start on one line and each new line in the file is considered an embedded newline in the cell.

Best way to convert strings to symbols in hash

Starting on Psych 3.0 you can add the symbolize_names: option

Psych.load("---\n foo: bar") # => {"foo"=>"bar"}

Psych.load("---\n foo: bar", symbolize_names: true) # => {:foo=>"bar"}

Note: if you have a lower Psych version than 3.0 symbolize_names: will be silently ignored.

My Ubuntu 18.04 includes it out of the box with ruby 2.5.1p57

SimpleXml to string

Here is a function I wrote to solve this issue (assuming tag has no attributes). This function will keep HTML formatting in the node:

function getAsXMLContent($xmlElement)
{
  $content=$xmlElement->asXML();

  $end=strpos($content,'>');
  if ($end!==false)
  {
    $tag=substr($content, 1, $end-1);

    return str_replace(array('<'.$tag.'>', '</'.$tag.'>'), '', $content);
  }
  else
    return '';
}


$string = "<element><child>Hello World</child></element>";
$xml = new SimpleXMLElement($string);

echo getAsXMLContent($xml->child); // prints Hello World

Could not locate Gemfile

You do not have Gemfile in a directory where you run that command. Gemfile is a file containing your gem settings for a current program.

forcing web-site to show in landscape mode only

@Golmaal really answered this, I'm just being a bit more verbose.

<style type="text/css">
    #warning-message { display: none; }
    @media only screen and (orientation:portrait){
        #wrapper { display:none; }
        #warning-message { display:block; }
    }
    @media only screen and (orientation:landscape){
        #warning-message { display:none; }
    }
</style>

....

<div id="wrapper">
    <!-- your html for your website -->
</div>
<div id="warning-message">
    this website is only viewable in landscape mode
</div>

You have no control over the user moving the orientation however you can at least message them. This example will hide the wrapper if in portrait mode and show the warning message and then hide the warning message in landscape mode and show the portrait.

I don't think this answer is any better than @Golmaal , only a compliment to it. If you like this answer, make sure to give @Golmaal the credit.

Update

I've been working with Cordova a lot recently and it turns out you CAN control it when you have access to the native features.

Another Update

So after releasing Cordova it is really terrible in the end. It is better to use something like React Native if you want JavaScript. It is really amazing and I know it isn't pure web but the pure web experience on mobile kind of failed.

How to get rid of the "No bootable medium found!" error in Virtual Box?

Follow the steps below:

1) Select your VM Instance. Go to Settings->Storage

2) Under the storage tree select the default image or "Empty"(which ever is present)

3) Under the attributes frame, click on the CD image and select "Choose a virtual CD/DVD disk file"

4) Browse and select the image file(iso or what ever format) from the system

5) Select OK.

Abishek's solution is correct. But the highlighted area in 2nd image could be misleading.

An exception of type 'System.NullReferenceException' occurred in myproject.DLL but was not handled in user code

It means you have a null reference somewhere in there. Can you debug the app and stop the debugger when it gets here and investigate? Probably img1 is null or ConfigurationManager.AppSettings.Get("Url") is returning null.

jQuery.parseJSON throws “Invalid JSON” error due to escaped single quote in JSON

I understand where the problem lies and when I look at the specs its clear that unescaped single quotes should be parsed correctly.

I am using jquery`s jQuery.parseJSON function to parse the JSON string but still getting the parse error when there is a single quote in the data that is prepared with json_encode.

Could it be a mistake in my implementation that looks like this (PHP - server side):

$data = array();

$elem = array();
$elem['name'] = 'Erik';
$elem['position'] = 'PHP Programmer';
$data[] = json_encode($elem);

$elem = array();
$elem['name'] = 'Carl';
$elem['position'] = 'C Programmer';
$data[] = json_encode($elem);

$jsonString = "[" . implode(", ", $data) . "]";

The final step is that I store the JSON encoded string into an JS variable:

<script type="text/javascript">
employees = jQuery.parseJSON('<?=$marker; ?>');
</script>

If I use "" instead of '' it still throws an error.

SOLUTION:

The only thing that worked for me was to use bitmask JSON_HEX_APOS to convert the single quotes like this:

json_encode($tmp, JSON_HEX_APOS);

Is there another way of tackle this issue? Is my code wrong or poorly written?

Thanks

ViewPager and fragments — what's the right way to store fragment's state?

A bit different opinion instead of storing the Fragments yourself just leave it to the FragmentManager and when you need to do something with the fragments look for them in the FragmentManager:

//make sure you have the right FragmentManager 
//getSupportFragmentManager or getChildFragmentManager depending on what you are using to manage this stack of fragments
List<Fragment> fragments = fragmentManager.getFragments();
if(fragments != null) {
   int count = fragments.size();
   for (int x = 0; x < count; x++) {
       Fragment fragment = fragments.get(x);
       //check if this is the fragment we want, 
       //it may be some other inspection, tag etc.
       if (fragment instanceof MyFragment) {
           //do whatever we need to do with it
       }
   }
}

If you have a lot of Fragments and the cost of instanceof check may be not what you want, but it is good thing to have in mind that the FragmentManager already keeps account of Fragments.

How to load/reference a file as a File instance from the classpath

Try getting hold of a URL for your classpath resource:

URL url = this.getClass().getResource("/com/path/to/file.txt")

Then create a file using the constructor that accepts a URI:

File file = new File(url.toURI());

How to get element value in jQuery

<ul id="unOrderedList">
<li value="2">Whatever</li>
.
.



 $('#unOrderedList li').click(function(){
      var value = $(this).attr('value');
     alert(value); 
  });

Your looking for the attribute "value" inside the "li" tag

Importing CSV data using PHP/MySQL

Database Connection:

 try {
        $conn = mysqli_connect($servername, $username, $password, $db);
        //echo "Connected successfully"; 
    } catch (exception $e) {
        echo "Connection failed: " . $e->getMessage();
    }

Code to read CSV file and upload to table in database.

   $file = fopen($filename, "r");
            while (($getData = fgetcsv($file, 10000, ",")) !== FALSE) {
                $sql = "INSERT into db_table 
                   values ('','" . $getData[1] . "','" . $getData[2] . "','" . $getData[3] . "','" . $getData[4] . "','" . $getData[5] . "','" . $getData[6] . "')";
                $result = mysqli_query($conn, $sql);
                if (!isset($result)) {
                    echo "<script type=\"text/javascript\">
                            alert(\"Invalid File:Please Upload CSV File. 
                            window.location = \"home.do\"
                          </script>";
                } else {
                    echo "<script type=\"text/javascript\">
                        alert(\"CSV File has been successfully Imported.\");
                        window.location = \"home.do\"
                    </script>";
                }
            }
            fclose($file);

Get free disk space

this works for me...

using System.IO;

private long GetTotalFreeSpace(string driveName)
{
    foreach (DriveInfo drive in DriveInfo.GetDrives())
    {
        if (drive.IsReady && drive.Name == driveName)
        {
            return drive.TotalFreeSpace;
        }
    }
    return -1;
}

good luck!

Creating self signed certificate for domain and subdomains - NET::ERR_CERT_COMMON_NAME_INVALID

The answers provided did not work for me (Chrome or Firefox) while creating PWA for local development and testing. DO NOT USE FOR PRODUCTION! I was able to use the following:

  1. Online certificate tools site with the following options:
    • Common Names: Add both the "localhost" and IP of your system e.g. 192.168.1.12
    • Subject Alternative Names: Add "DNS" = "localhost" and "IP" = <your ip here, e.g. 192.168.1.12>
    • "CRS" drop down options set to "Self Sign"
    • all other options were defaults
  2. Download all links
  3. Import .p7b cert into Windows by double clicking and select "install"/ OSX?/Linux?
  4. Added certs to node app... using Google's PWA example
    • add const https = require('https'); const fs = require('fs'); to the top of the server.js file
    • comment out return app.listen(PORT, () => { ... }); at the bottom of server.js file
    • add below https.createServer({ key: fs.readFileSync('./cert.key','utf8'), cert: fs.readFileSync('./cert.crt','utf8'), requestCert: false, rejectUnauthorized: false }, app).listen(PORT)

I have no more errors in Chrome or Firefox

Java - How do I make a String array with values?

Another way to create an array with String apart from

String[] strings =  { "abc", "def", "hij", "xyz" };

is to use split. I find this more readable if there are lots of Strings.

String[] strings =  "abc,def,hij,xyz".split(",");

or the following is good if you are parsing lines of strings from another source.

String[] strings =  ("abc\n" +
                     "def\n" +
                     "hij\n" +
                     "xyz").split("\n");

Implementing Singleton with an Enum (in Java)

In this Java best practices book by Joshua Bloch, you can find explained why you should enforce the Singleton property with a private constructor or an Enum type. The chapter is quite long, so keeping it summarized:

Making a class a Singleton can make it difficult to test its clients, as it’s impossible to substitute a mock implementation for a singleton unless it implements an interface that serves as its type. Recommended approach is implement Singletons by simply make an enum type with one element:

// Enum singleton - the preferred approach
public enum Elvis {
INSTANCE;
public void leaveTheBuilding() { ... }
}

This approach is functionally equivalent to the public field approach, except that it is more concise, provides the serialization machinery for free, and provides an ironclad guarantee against multiple instantiation, even in the face of sophisticated serialization or reflection attacks.

While this approach has yet to be widely adopted, a single-element enum type is the best way to implement a singleton.

Android - default value in editText

We wish there is a default value attribute in each view of android views or group view in future versions of SDK. but to overcome that, simply before submission, check if the view is empty equal true, then assign a default value

example:

   /* add 0 as default numeric value to a price field when skipped by a user,
                    in order to avoid parsing error of empty or improper format value. */
                    if (Objects.requireNonNull(edPrice.getText()).toString().trim().isEmpty())
                    edPrice.setText("0");

C++ create string of text and variables

See also boost::format:

#include <boost/format.hpp>

std::string var = (boost::format("somtext %s sometext %s") % somevar % somevar).str();

Java 8 Lambda Stream forEach with multiple statements

In the first case alternatively to multiline forEach you can use the peek stream operation:

entryList.stream()
         .peek(entry -> entry.setTempId(tempId))
         .forEach(updatedEntries.add(entityManager.update(entry, entry.getId())));

In the second case I'd suggest to extract the loop body to the separate method and use method reference to call it via forEach. Even without lambdas it would make your code more clear as the loop body is independent algorithm which processes the single entry so it might be useful in other places as well and can be tested separately.

Update after question editing. if you have checked exceptions then you have two options: either change them to unchecked ones or don't use lambdas/streams at this piece of code at all.

Which is the best library for XML parsing in java

Nikita's point is an excellent one: don't confuse mature with bad. XML hasn't changed much.

JDOM would be another alternative to DOM4J.

Updating a dataframe column in spark

Commonly when updating a column, we want to map an old value to a new value. Here's a way to do that in pyspark without UDF's:

# update df[update_col], mapping old_value --> new_value
from pyspark.sql import functions as F
df = df.withColumn(update_col,
    F.when(df[update_col]==old_value,new_value).
    otherwise(df[update_col])).

How to build a query string for a URL in C#?

I added the following method to my PageBase class.

protected void Redirect(string url)
    {
        Response.Redirect(url);
    }
protected void Redirect(string url, NameValueCollection querystrings)
    {
        StringBuilder redirectUrl = new StringBuilder(url);

        if (querystrings != null)
        {
            for (int index = 0; index < querystrings.Count; index++)
            {
                if (index == 0)
                {
                    redirectUrl.Append("?");
                }

                redirectUrl.Append(querystrings.Keys[index]);
                redirectUrl.Append("=");
                redirectUrl.Append(HttpUtility.UrlEncode(querystrings[index]));

                if (index < querystrings.Count - 1)
                {
                    redirectUrl.Append("&");
                }
            }
        }

        this.Redirect(redirectUrl.ToString());
    }

To call:

NameValueCollection querystrings = new NameValueCollection();    
querystrings.Add("language", "en");
querystrings.Add("id", "134");
this.Redirect("http://www.mypage.com", querystrings);

How do I initialize the base (super) class?

How do I initialize the base (super) class?

class SuperClass(object):
    def __init__(self, x):
        self.x = x

class SubClass(SuperClass):
    def __init__(self, y):
        self.y = y

Use a super object to ensure you get the next method (as a bound method) in the method resolution order. In Python 2, you need to pass the class name and self to super to lookup the bound __init__ method:

 class SubClass(SuperClass):
      def __init__(self, y):
          super(SubClass, self).__init__('x')
          self.y = y

In Python 3, there's a little magic that makes the arguments to super unnecessary - and as a side benefit it works a little faster:

 class SubClass(SuperClass):
      def __init__(self, y):
          super().__init__('x')
          self.y = y

Hardcoding the parent like this below prevents you from using cooperative multiple inheritance:

 class SubClass(SuperClass):
      def __init__(self, y):
          SuperClass.__init__(self, 'x') # don't do this
          self.y = y

Note that __init__ may only return None - it is intended to modify the object in-place.

Something __new__

There's another way to initialize instances - and it's the only way for subclasses of immutable types in Python. So it's required if you want to subclass str or tuple or another immutable object.

You might think it's a classmethod because it gets an implicit class argument. But it's actually a staticmethod. So you need to call __new__ with cls explicitly.

We usually return the instance from __new__, so if you do, you also need to call your base's __new__ via super as well in your base class. So if you use both methods:

class SuperClass(object):
    def __new__(cls, x):
        return super(SuperClass, cls).__new__(cls)
    def __init__(self, x):
        self.x = x

class SubClass(object):
    def __new__(cls, y):
        return super(SubClass, cls).__new__(cls)

    def __init__(self, y):
        self.y = y
        super(SubClass, self).__init__('x')

Python 3 sidesteps a little of the weirdness of the super calls caused by __new__ being a static method, but you still need to pass cls to the non-bound __new__ method:

class SuperClass(object):
    def __new__(cls, x):
        return super().__new__(cls)
    def __init__(self, x):
        self.x = x

class SubClass(object):
    def __new__(cls, y):
        return super().__new__(cls)
    def __init__(self, y):
        self.y = y
        super().__init__('x')

mysql query result in php variable

$query    =    "SELECT username, userid FROM user WHERE username = 'admin' ";
$result    =    $conn->query($query);

if (!$result) {
  echo 'Could not run query: ' . mysql_error();
  exit;
}

$arrayResult    =    mysql_fetch_array($result);

//Now you can access $arrayResult like this

$arrayResult['userid'];    // output will be userid which will be in database
$arrayResult['username'];  // output will be admin

//Note- userid and username will be column name of user table.

Where are logs located?

You should be checking the root directory and not the app directory.

Look in $ROOT/storage/laravel.log not app/storage/laravel.log, where root is the top directory of the project.

How do I assign ls to an array in Linux Bash?

This would print the files in those directories line by line.

array=(ww/* ee/* qq/*)
printf "%s\n" "${array[@]}"

How to fix: "HAX is not working and emulator runs in emulation mode"

For Windows.

In Android Studio:

Tools > Android > AVD Manager > Your Device > Pencil Icon> Show Advanced Settings > Memory and Storage > RAM > Set RAM to your preferred size.

In Control Panel:

Programs and Features > Intel Hardware Accelerated Execution Manager > Change > Set manually > Set RAM to your preferred size.

It is better for RAM sizes set in both places to be the same.

Calculating the SUM of (Quantity*Price) from 2 different tables

select orderID, sum(subtotal) as order_total from
(
    select orderID, productID, price, qty, price * qty as subtotal
    from product p inner join orderitem o on p.id = o.productID
    where o.orderID = @orderID
) t
group by orderID

ActionBarActivity: cannot be resolved to a type

This way work for me with Eclipse in Android developer tool from Google -righ click - property - java build path - add external JAR

point to: android-support-v7-appcompat.jar in /sdk/extras/android/support/v7/appcompat/libs

Then

import android.support.v7.app.ActionBarActivity;

SQL Server Pivot Table with multiple column aggregates

I used your own pivot as a nested query and came to this result:

SELECT
  [sub].[chardate],
  SUM(ISNULL([Australia], 0)) AS [Transactions Australia],
  SUM(CASE WHEN [Australia] IS NOT NULL THEN [TotalAmount] ELSE 0 END) AS [Amount Australia],
  SUM(ISNULL([Austria], 0)) AS [Transactions Austria],
  SUM(CASE WHEN [Austria] IS NOT NULL THEN [TotalAmount] ELSE 0 END) AS [Amount Austria]
FROM
(
  select * 
  from  mytransactions
  pivot (sum (totalcount) for country in ([Australia], [Austria])) as pvt
) AS [sub]
GROUP BY
  [sub].[chardate],
  [sub].[numericmonth]
ORDER BY 
  [sub].[numericmonth] ASC

Here is the Fiddle.

How to set image in circle in swift

import UIKit

class ViewController: UIViewController {
  @IBOutlet weak var image: UIImageView!

  override func viewDidLoad() {
    super.viewDidLoad()

    image.layer.borderWidth = 1
    image.layer.masksToBounds = false
    image.layer.borderColor = UIColor.black.cgColor
    image.layer.cornerRadius = image.frame.height/2
    image.clipsToBounds = true
}

If you want it on an extension

import UIKit

extension UIImageView {

    func makeRounded() {

        self.layer.borderWidth = 1
        self.layer.masksToBounds = false
        self.layer.borderColor = UIColor.black.cgColor
        self.layer.cornerRadius = self.frame.height / 2
        self.clipsToBounds = true
    }
}

That is all you need....

How to run a script at the start up of Ubuntu?

First of all, the easiest way to run things at startup is to add them to the file /etc/rc.local.

Another simple way is to use @reboot in your crontab. Read the cron manpage for details.

However, if you want to do things properly, in addition to adding a script to /etc/init.d you need to tell ubuntu when the script should be run and with what parameters. This is done with the command update-rc.d which creates a symlink from some of the /etc/rc* directories to your script. So, you'd need to do something like:

update-rc.d yourscriptname start 2

However, real init scripts should be able to handle a variety of command line options and otherwise integrate to the startup process. The file /etc/init.d/README has some details and further pointers.

How to disable back swipe gesture in UINavigationController on iOS 7

I found out setting the gesture to disabled only doesn't always work. It does work, but for me it only did after I once used the backgesture. Second time it wouldn't trigger the backgesture.

Fix for me was to delegate the gesture and implement the shouldbegin method to return NO:

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];

    // Disable iOS 7 back gesture
    if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
        self.navigationController.interactivePopGestureRecognizer.enabled = NO;
        self.navigationController.interactivePopGestureRecognizer.delegate = self;
    }
}

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];

    // Enable iOS 7 back gesture
    if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
        self.navigationController.interactivePopGestureRecognizer.enabled = YES;
        self.navigationController.interactivePopGestureRecognizer.delegate = nil;
    }
}

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
    return NO;
}

What's the difference between SHA and AES encryption?

SHA isn't encryption, it's a one-way hash function. AES (Advanced_Encryption_Standard) is a symmetric encryption standard.

AES Reference

Select by partial string from a pandas DataFrame

There are answers before this which accomplish the asked feature, anyway I would like to show the most generally way:

df.filter(regex=".*STRING_YOU_LOOK_FOR.*")

This way let's you get the column you look for whatever the way is wrote.

( Obviusly, you have to write the proper regex expression for each case )

What's the difference between INNER JOIN, LEFT JOIN, RIGHT JOIN and FULL JOIN?

INNER JOIN gets all records that are common between both tables based on the supplied ON clause.

LEFT JOIN gets all records from the LEFT linked and the related record from the right table ,but if you have selected some columns from the RIGHT table, if there is no related records, these columns will contain NULL.

RIGHT JOIN is like the above but gets all records in the RIGHT table.

FULL JOIN gets all records from both tables and puts NULL in the columns where related records do not exist in the opposite table.

Selecting empty text input using jQuery

I'd recommend:

$('input:text:not([value])')

How to get date, month, year in jQuery UI datepicker?

what about that simple way)

$(document).ready ->
 $('#datepicker').datepicker( dateFormat: 'yy-mm-dd',  onSelect: (dateStr) ->
    alert dateStr # yy-mm-dd
    #OR
    alert $("#datepicker").val(); # yy-mm-dd

How to create a directory and give permission in single command

According to mkdir's man page...

mkdir -m 777 dirname

How do I get a value of datetime.today() in Python that is "timezone aware"?

Another method to construct time zone aware datetime object representing current time:

import datetime
import pytz

pytz.utc.localize( datetime.datetime.utcnow() )  

You can install pytz from PyPI by running:

$ pipenv install pytz

"cannot be used as a function error"

You can't pass a function as a parameter. Simply remove it from estimatedPopulation() and replace it with 'float growthRate'. use this in your calculation instead of calling the function:

int estimatedPopulation (int currentPopulation, float growthRate)
{
    return (currentPopulation + currentPopulation * growthRate / 100);
}

and call it as:

int foo = estimatedPopulation (currentPopulation, growthRate (birthRate, deathRate));

C++, How to determine if a Windows Process is running?

You may find if a process (given its name or PID) is running or not by iterating over the running processes simply by taking a snapshot of running processes via CreateToolhelp32Snapshot, and by using Process32First and Process32Next calls on that snapshot.

Then you may use th32ProcessID field or szExeFile field of the resulting PROCESSENTRY32 struct depending on whether you want to search by PID or executable name. A simple implementation can be found here.

C# ASP.NET Single Sign-On Implementation

UltimateSAML SSO is an OASIS SAML v1.x and v2.0 specifications compliant .NET toolkit. It offers an elegant and easy way to add support for Single Sign-On and Single-Logout SAML to your ASP.NET, ASP.NET MVC, ASP.NET Core, Desktop, and Service applications. The lightweight library helps you provide SSO access to cloud and intranet websites using a single credentials entry.

Detailed UltimateSAML SSO review can be found here

Simple WPF RadioButton Binding?

I created an attached property based on Aviad's Answer which doesn't require creating a new class

public static class RadioButtonHelper
{
    [AttachedPropertyBrowsableForType(typeof(RadioButton))]
    public static object GetRadioValue(DependencyObject obj) => obj.GetValue(RadioValueProperty);
    public static void SetRadioValue(DependencyObject obj, object value) => obj.SetValue(RadioValueProperty, value);
    public static readonly DependencyProperty RadioValueProperty =
        DependencyProperty.RegisterAttached("RadioValue", typeof(object), typeof(RadioButtonHelper), new PropertyMetadata(new PropertyChangedCallback(OnRadioValueChanged)));

    private static void OnRadioValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if (d is RadioButton rb)
        {
            rb.Checked -= OnChecked;
            rb.Checked += OnChecked;
        }
    }

    public static void OnChecked(object sender, RoutedEventArgs e)
    {
        if (sender is RadioButton rb)
        {
            rb.SetCurrentValue(RadioBindingProperty, rb.GetValue(RadioValueProperty));
        }
    }

    [AttachedPropertyBrowsableForType(typeof(RadioButton))]
    public static object GetRadioBinding(DependencyObject obj) => obj.GetValue(RadioBindingProperty);
    public static void SetRadioBinding(DependencyObject obj, object value) => obj.SetValue(RadioBindingProperty, value);

    public static readonly DependencyProperty RadioBindingProperty =
        DependencyProperty.RegisterAttached("RadioBinding", typeof(object), typeof(RadioButtonHelper), new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, new PropertyChangedCallback(OnRadioBindingChanged)));

    private static void OnRadioBindingChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if (d is RadioButton rb && rb.GetValue(RadioValueProperty).Equals(e.NewValue))
        {
            rb.SetCurrentValue(RadioButton.IsCheckedProperty, true);
        }
    }
}

usage :

<RadioButton GroupName="grp1" Content="Value 1"
    helpers:RadioButtonHelper.RadioValue="val1" helpers:RadioButtonHelper.RadioBinding="{Binding SelectedValue}"/>
<RadioButton GroupName="grp1" Content="Value 2"
    helpers:RadioButtonHelper.RadioValue="val2" helpers:RadioButtonHelper.RadioBinding="{Binding SelectedValue}"/>
<RadioButton GroupName="grp1" Content="Value 3"
    helpers:RadioButtonHelper.RadioValue="val3" helpers:RadioButtonHelper.RadioBinding="{Binding SelectedValue}"/>
<RadioButton GroupName="grp1" Content="Value 4"
    helpers:RadioButtonHelper.RadioValue="val4" helpers:RadioButtonHelper.RadioBinding="{Binding SelectedValue}"/>

Merging Cells in Excel using C#

Excel.Application xl = new Excel.ApplicationClass();

Excel.Workbook wb = xl.Workbooks.Add(Excel.XlWBATemplate.xlWBATWorkshe et);

Excel.Worksheet ws = (Excel.Worksheet)wb.ActiveSheet;

ws.Cells[1,1] = "Testing";

Excel.Range range = ws.get_Range(ws.Cells[1,1],ws.Cells[1,2]);

range.Merge(true);

range.Interior.ColorIndex =36;

xl.Visible =true;

How to scroll to top of the page in AngularJS?

use: $anchorScroll();

with $anchorScroll property

In R, how to find the standard error of the mean?

The standard error is just the standard deviation divided by the square root of the sample size. So you can easily make your own function:

> std <- function(x) sd(x)/sqrt(length(x))
> std(c(1,2,3,4))
[1] 0.6454972

Check if a Postgres JSON array contains a string

Not smarter but simpler:

select info->>'name' from rabbits WHERE info->>'food' LIKE '%"carrots"%';

What are the most common font-sizes for H1-H6 tags

Headings are normally bold-faced; that has been turned off for this demonstration of size correspondence. MSIE and Opera interpret these sizes the same, but note that Gecko browsers and Chrome interpret Heading 6 as 11 pixels instead of 10 pixels/font size 1, and Heading 3 as 19 pixels instead of 18 pixels/font size 4 (though it's difficult to tell the difference even in a direct comparison and impossible in use). It seems Gecko also limits text to no smaller than 10 pixels.

Spin or rotate an image on hover

Here is my code, this flips on hover and flips back off-hover.

CSS:

.flip-container {
  background: transparent;
  display: inline-block;
}

.flip-this {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.6s;
  transform-style: preserve-3d;
}

.flip-container:hover .flip-this {
  transition: 0.9s;
  transform: rotateY(180deg);
}

HTML:

<div class="flip-container">
    <div class="flip-this">
        <img width="100" alt="Godot icon" src="https://upload.wikimedia.org/wikipedia/commons/thumb/6/6a/Godot_icon.svg/512px-Godot_icon.svg.png">
    </div>
</div>

Fiddle this

How to convert string to boolean in typescript Angular 4

You can use that:

let s: string = "true";
let b: boolean = Boolean(s);

Postman Chrome: What is the difference between form-data, x-www-form-urlencoded and raw

These are different Form content types defined by W3C. If you want to send simple text/ ASCII data, then x-www-form-urlencoded will work. This is the default.

But if you have to send non-ASCII text or large binary data, the form-data is for that.

You can use Raw if you want to send plain text or JSON or any other kind of string. Like the name suggests, Postman sends your raw string data as it is without modifications. The type of data that you are sending can be set by using the content-type header from the drop down.

Binary can be used when you want to attach non-textual data to the request, e.g. a video/audio file, images, or any other binary data file.

Refer to this link for further reading: Forms in HTML documents

Use a URL to link to a Google map with a marker on it

If working with Basic4Android and looking for an easy fix to the problem, try this it works both Google maps and Openstreet even though OSM creates a bit of a messy result and thanx to [yndolok] for the google marker

GooglemLoc="https://www.google.com/maps/place/"&[Latitude]&"+"&[Longitude]&"/@"&[Latitude]&","&[Longitude]&",15z" 

GooglemRute="https://www.google.co.ls/maps/dir/"&[FrmLatt]&","&[FrmLong]&"/"&[ToLatt]&","&[FrmLong]&"/@"&[ScreenX]&","&[ScreenY]&",14z/data=!3m1!4b1!4m2!4m1!3e0?hl=en"  'route ?hl=en

OpenStreetLoc="https://www.openstreetmap.org/#map=16/"&[Latitude]&"/"&[Longitude]&"&layers=N"

OpenStreetRute="https://www.openstreetmap.org/directions?engine=osrm_car&route="&[FrmLatt]&"%2C"&[FrmLong]&"%3B"&[ToLatt]&"%2C"&[ToLong]&"#Map=15/"&[ScreenX]&"/"&[Screeny]&"&layers=N"

SQL Server 2005 Setting a variable to the result of a select query

You could also just put the first SELECT in a subquery. Since most optimizers will fold it into a constant anyway, there should not be a performance hit on this.

Incidentally, since you are using a predicate like this:

CONVERT(...) = CONVERT(...)

that predicate expression cannot be optimized properly or use indexes on the columns reference by the CONVERT() function.

Here is one way to make the original query somewhat better:

DECLARE @ooDate datetime
SELECT @ooDate = OO.Date FROM OLAP.OutageHours AS OO where OO.OutageID = 1

SELECT 
  COUNT(FF.HALID)
FROM
  Outages.FaultsInOutages AS OFIO 
  INNER JOIN Faults.Faults as FF ON 
    FF.HALID = OFIO.HALID 
WHERE
  FF.FaultDate >= @ooDate AND
  FF.FaultDate < DATEADD(day, 1, @ooDate) AND
  OFIO.OutageID = 1

This version could leverage in index that involved FaultDate, and achieves the same goal.

Here it is, rewritten to use a subquery to avoid the variable declaration and subsequent SELECT.

SELECT 
  COUNT(FF.HALID)
FROM
  Outages.FaultsInOutages AS OFIO 
  INNER JOIN Faults.Faults as FF ON 
    FF.HALID = OFIO.HALID 
WHERE
  CONVERT(varchar(10), FF.FaultDate, 126) = (SELECT CONVERT(varchar(10), OO.Date, 126) FROM OLAP.OutageHours AS OO where OO.OutageID = 1) AND
  OFIO.OutageID = 1

Note that this approach has the same index usage issue as the original, because of the use of CONVERT() on FF.FaultDate. This could be remedied by adding the subquery twice, but you would be better served with the variable approach in this case. This last version is only for demonstration.

Regards.

IsNullOrEmpty with Object

object MyObject = null;

if (MyObject != null && !string.IsNullOrEmpty(MyObject.ToString())) { ... }

Entity framework code-first null foreign key

I have the same problem now , I have foreign key and i need put it as nullable, to solve this problem you should put

    modelBuilder.Entity<Country>()
        .HasMany(c => c.Users)
        .WithOptional(c => c.Country)
        .HasForeignKey(c => c.CountryId)
        .WillCascadeOnDelete(false);

in DBContext class I am sorry for answer you very late :)

Best way to import Observable from rxjs

Update for RxJS 6 (April 2018)

It is now perfectly fine to import directly from rxjs. (As can be seen in Angular 6+). Importing from rxjs/operators is also fine and it is actually no longer possible to import operators globally (one of major reasons for refactoring rxjs 6 and the new approach using pipe). Thanks to this treeshaking can now be used as well.

Sample code from rxjs repo:

import { Observable, Subject, ReplaySubject, from, of, range } from 'rxjs';
import { map, filter, switchMap } from 'rxjs/operators';

range(1, 200)
  .pipe(filter(x => x % 2 === 1), map(x => x + x))
  .subscribe(x => console.log(x));

Backwards compatibility for rxjs < 6?

rxjs team released a compatibility package on npm that is pretty much install & play. With this all your rxjs 5.x code should run without any issues. This is especially useful now when most of the dependencies (i.e. modules for Angular) are not yet updated.

Auto Resize Image in CSS FlexBox Layout and keeping Aspect Ratio?

In the second image it looks like you want the image to fill the box, but the example you created DOES keep the aspect ratio (the pets look normal, not slim or fat).

I have no clue if you photoshopped those images as example or the second one is "how it should be" as well (you said IS, while the first example you said "should")

Anyway, I have to assume:

If "the images are not resized keeping the aspect ration" and you show me an image which DOES keep the aspect ratio of the pixels, I have to assume you are trying to accomplish the aspect ratio of the "cropping" area (the inner of the green) WILE keeping the aspect ratio of the pixels. I.e. you want to fill the cell with the image, by enlarging and cropping the image.

If that's your problem, the code you provided does NOT reflect "your problem", but your starting example.

Given the previous two assumptions, what you need can't be accomplished with actual images if the height of the box is dynamic, but with background images. Either by using "background-size: contain" or these techniques (smart paddings in percents that limit the cropping or max sizes anywhere you want): http://fofwebdesign.co.uk/template/_testing/scale-img/scale-img.htm

The only way this is possible with images is if we FORGET about your second iimage, and the cells have a fixed height, and FORTUNATELY, judging by your sample images, the height stays the same!

So if your container's height doesn't change, and you want to keep your images square, you just have to set the max-height of the images to that known value (minus paddings or borders, depending on the box-sizing property of the cells)

Like this:

<div class="content">
  <div class="row">    
      <div class="cell">    
          <img src="http://lorempixel.com/output/people-q-c-320-320-2.jpg"/>
      </div>
      <div class="cell">    
          <img src="http://lorempixel.com/output/people-q-c-320-320-7.jpg"/>
      </div>
    </div>
</div>

And the CSS:

.content {
    background-color: green;
}

.row {
    display: -webkit-box;
    display: -moz-box;
    display: -ms-flexbox;
    display: -webkit-flex;
    display: flex;

    -webkit-box-orient: horizontal; 
    -moz-box-orient: horizontal;
    box-orient: horizontal;
    flex-direction: row;

    -webkit-box-pack: center;
    -moz-box-pack: center;
    box-pack: center;
    justify-content: center;

    -webkit-box-align: center;
    -moz-box-align: center;
    box-align: center;  
    align-items: center;

}

.cell {
    -webkit-box-flex: 1;
    -moz-box-flex: 1;
    box-flex: 1;
    -webkit-flex: 1 1 auto;
    flex: 1 1 auto;
    padding: 10px;
    border: solid 10px red;
    text-align: center;
    height: 300px;
    display: flex;
    align-items: center;
    box-sizing: content-box;
}
img {
    margin: auto;
    width: 100%;
    max-width: 300px;
    max-height:100%
}

http://jsfiddle.net/z25heocL/

Your code is invalid (opening tags are instead of closing ones, so they output NESTED cells, not siblings, he used a SCREENSHOT of your images inside the faulty code, and the flex box is not holding the cells but both examples in a column (you setup "row" but the corrupt code nesting one cell inside the other resulted in a flex inside a flex, finally working as COLUMNS. I have no idea what you wanted to accomplish, and how you came up with that code, but I'm guessing what you want is this.

I added display: flex to the cells too, so the image gets centered (I think display: table could have been used here as well with all this markup)

How to change default text file encoding in Eclipse?

Window -> Preferences -> General -> Workspace : Text file encoding

How do I get ASP.NET Web API to return JSON instead of XML using Chrome?

If you do this in the WebApiConfig you will get JSON by default, but it will still allow you to return XML if you pass text/xml as the request Accept header

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );

        var appXmlType = config.Formatters.XmlFormatter.SupportedMediaTypes.FirstOrDefault(t => t.MediaType == "application/xml");
        config.Formatters.XmlFormatter.SupportedMediaTypes.Remove(appXmlType);
    }
}

If you are not using the MVC project type and therefore did not have this class to begin with, see this answer for details on how to incorporate it.

IIS7 Settings File Locations

It sounds like you're looking for applicationHost.config, which is located in C:\Windows\System32\inetsrv\config.

Yes, it's an XML file, and yes, editing the file by hand will affect the IIS config after a restart. You can think of IIS Manager as a GUI front-end for editing applicationHost.config and web.config.

generate model using user:references vs user_id:integer

how does rails know that user_id is a foreign key referencing user?

Rails itself does not know that user_id is a foreign key referencing user. In the first command rails generate model Micropost user_id:integer it only adds a column user_id however rails does not know the use of the col. You need to manually put the line in the Micropost model

class Micropost < ActiveRecord::Base
  belongs_to :user
end

class User < ActiveRecord::Base
  has_many :microposts
end

the keywords belongs_to and has_many determine the relationship between these models and declare user_id as a foreign key to User model.

The later command rails generate model Micropost user:references adds the line belongs_to :user in the Micropost model and hereby declares as a foreign key.

FYI
Declaring the foreign keys using the former method only lets the Rails know about the relationship the models/tables have. The database is unknown about the relationship. Therefore when you generate the EER Diagrams using software like MySql Workbench you find that there is no relationship threads drawn between the models. Like in the following pic enter image description here

However, if you use the later method you find that you migration file looks like:

def change
    create_table :microposts do |t|
      t.references :user, index: true

      t.timestamps null: false
    end
    add_foreign_key :microposts, :users

Now the foreign key is set at the database level. and you can generate proper EER diagrams. enter image description here

jQuery 'input' event

Occurs when the text content of an element is changed through the user interface.

It's not quite an alias for keyup because keyup will fire even if the key does nothing (for example: pressing and then releasing the Control key will trigger a keyup event).

A good way to think about it is like this: it's an event that triggers whenever the input changes. This includes -- but is not limited to -- pressing keys which modify the input (so, for example, Ctrl by itself will not trigger the event, but Ctrl-V to paste some text will), selecting an auto-completion option, Linux-style middle-click paste, drag-and-drop, and lots of other things.

See this page and the comments on this answer for more details.

Cocoa Touch: How To Change UIView's Border Color And Thickness?

[self.view.layer setBorderColor: [UIColor colorWithRed:0.265 green:0.447 blue:0.767 alpha:1.0f].CGColor];

simple Jquery hover enlarge

Well I'm not exactly sure why your code is not working because I usually follow a different approach when trying to accomplish something similar.

But your code is erroring out.. There seems to be an issue with the way you are using scale I got the jQuery to actually execute by changing your code to the following.

$(document).ready(function(){
    $('img').hover(function() {
        $(this).css("cursor", "pointer");
        $(this).toggle({
          effect: "scale",
          percent: "90%"
        },200);
    }, function() {
         $(this).toggle({
           effect: "scale",
           percent: "80%"
         },200);

    });
});  

But I have always done it by using CSS to setup my scaling and transition..

Here is an example, hopefully it helps.

$(document).ready(function(){
    $('#content').hover(function() {
        $("#content").addClass('transition');

    }, function() {
        $("#content").removeClass('transition');
    });
});

http://jsfiddle.net/y4yAP/

Receiving login prompt using integrated windows authentication

I tried the above IIS configuration tricks and loopback registry hack, and I reviewed and recreated app pool permissions and a dozen other things and still wasn't able to get rid of the authentication loop running on my development workstation with IIS Express or IIS 7.5, from a local or remote browsing session. I received four 401.2 status responses and a blank page. The exact same site deployed to my IIS 8.5 staging server works flawlessly.

Finally I noticed markup in the Response Body that was rendered blank by the browser contained the default page for a successful log in. I determined that Custom Error handling for ASP.NET and HTTP for the 401 error was preventing/interfering with Windows Authentication my workstation but not the staging server. I spent several hours fiddling with this, but as soon as I removed custom handling for just the 401 error, the workstation was back to normal. I present this as yet one another way to shoot your own foot.

JavaScript check if value is only undefined, null or false

Boolean(val) === false. This worked for me to check if value was falsely.

Calculating distance between two geographic locations

    private static Double _MilesToKilometers = 1.609344;
    private static Double _MilesToNautical = 0.8684;


    /// <summary>
    /// Calculates the distance between two points of latitude and longitude.
    /// Great Link - http://www.movable-type.co.uk/scripts/latlong.html
    /// </summary>
    /// <param name="coordinate1">First coordinate.</param>
    /// <param name="coordinate2">Second coordinate.</param>
    /// <param name="unitsOfLength">Sets the return value unit of length.</param>
    public static Double Distance(Coordinate coordinate1, Coordinate coordinate2, UnitsOfLength unitsOfLength)
    {

        double theta = coordinate1.getLongitude() - coordinate2.getLongitude();
        double distance = Math.sin(ToRadian(coordinate1.getLatitude())) * Math.sin(ToRadian(coordinate2.getLatitude())) +
                       Math.cos(ToRadian(coordinate1.getLatitude())) * Math.cos(ToRadian(coordinate2.getLatitude())) *
                       Math.cos(ToRadian(theta));

        distance = Math.acos(distance);
        distance = ToDegree(distance);
        distance = distance * 60 * 1.1515;

        if (unitsOfLength == UnitsOfLength.Kilometer)
            distance = distance * _MilesToKilometers;
        else if (unitsOfLength == UnitsOfLength.NauticalMiles)
            distance = distance * _MilesToNautical;

        return (distance);

    }

Purpose of returning by const value?

It could be used as a wrapper function for returning a reference to a private constant data type. For example in a linked list you have the constants tail and head, and if you want to determine if a node is a tail or head node, then you can compare it with the value returned by that function.

Though any optimizer would most likely optimize it out anyway...

Which is the best Linux C/C++ debugger (or front-end to gdb) to help teaching programming?

You could try using Insight a graphical front-end for gdb written by Red Hat Or if you use GNOME desktop environment, you can also try Nemiver.

Incrementing in C++ - When to use x++ or ++x?

You explained the difference correctly. It just depends on if you want x to increment before every run through a loop, or after that. It depends on your program logic, what is appropriate.

An important difference when dealing with STL-Iterators (which also implement these operators) is, that it++ creates a copy of the object the iterator points to, then increments, and then returns the copy. ++it on the other hand does the increment first and then returns a reference to the object the iterator now points to. This is mostly just relevant when every bit of performance counts or when you implement your own STL-iterator.

Edit: fixed the mixup of prefix and suffix notation

How can I quickly and easily convert spreadsheet data to JSON?

Assuming you really mean easiest and are not necessarily looking for a way to do this programmatically, you can do this:

  1. Add, if not already there, a row of "column Musicians" to the spreadsheet. That is, if you have data in columns such as:

    Rory Gallagher      Guitar
    Gerry McAvoy        Bass
    Rod de'Ath          Drums
    Lou Martin          Keyboards
    Donkey Kong Sioux   Self-Appointed Semi-official Stomper
    

    Note: you might want to add "Musician" and "Instrument" in row 0 (you might have to insert a row there)

  2. Save the file as a CSV file.

  3. Copy the contents of the CSV file to the clipboard

  4. Go to http://www.convertcsv.com/csv-to-json.htm

  5. Verify that the "First row is column names" checkbox is checked

  6. Paste the CSV data into the content area

  7. Mash the "Convert CSV to JSON" button

    With the data shown above, you will now have:

    [
      {
        "MUSICIAN":"Rory Gallagher",
        "INSTRUMENT":"Guitar"
      },
      {
        "MUSICIAN":"Gerry McAvoy",
        "INSTRUMENT":"Bass"
      },
      {
        "MUSICIAN":"Rod D'Ath",
        "INSTRUMENT":"Drums"
      },
      {
        "MUSICIAN":"Lou Martin",
        "INSTRUMENT":"Keyboards"
      }
      {
        "MUSICIAN":"Donkey Kong Sioux",
        "INSTRUMENT":"Self-Appointed Semi-Official Stomper"
      }
    ]
    

    With this simple/minimalistic data, it's probably not required, but with large sets of data, it can save you time and headache in the proverbial long run by checking this data for aberrations and abnormalcy.

  8. Go here: http://jsonlint.com/

  9. Paste the JSON into the content area

  10. Pres the "Validate" button.

If the JSON is good, you will see a "Valid JSON" remark in the Results section below; if not, it will tell you where the problem[s] lie so that you can fix it/them.

Difference between CR LF, LF and CR line break types?

This is a good summary I found:

The Carriage Return (CR) character (0x0D, \r) moves the cursor to the beginning of the line without advancing to the next line. This character is used as a new line character in Commodore and Early Macintosh operating systems (OS-9 and earlier).

The Line Feed (LF) character (0x0A, \n) moves the cursor down to the next line without returning to the beginning of the line. This character is used as a new line character in UNIX based systems (Linux, Mac OSX, etc)

The End of Line (EOL) sequence (0x0D 0x0A, \r\n) is actually two ASCII characters, a combination of the CR and LF characters. It moves the cursor both down to the next line and to the beginning of that line. This character is used as a new line character in most other non-Unix operating systems including Microsoft Windows, Symbian OS and others.

Source

Windows 7 environment variable not working in path

My issue turned out to be embarrassingly simple:

Restart command prompt and the new variables should update

How to check if an element does NOT have a specific class?

reading through this 6yrs later and thought I'd also take a hack at it, also in the TIMTOWTDI vein...:D, hoping it isn't incorrect 'JS etiquette'.

I usually set up a var with the condition and then refer to it later on..i.e;

// var set up globally OR locally depending on your requirements
var hC;

function(el) {
  var $this = el;
  hC = $this.hasClass("test");

  // use the variable in the conditional statement
  if (!hC) {
    //
  }
}

Although I should mention that I do this because I mainly use the conditional ternary operator and want clean code. So in this case, all i'd have is this:

hC ? '' : foo(x, n) ;
   // OR -----------
!hC ? foo(x, n) : '' ;

...instead of this:

$this.hasClass("test") ? '' : foo(x, n) ;
   // OR -----------
(!$this.hasClass("test")) ? foo(x, n) : '' ;

How can I disable ARC for a single file in a project?

For Xcode 4.3 the easier way might be: Edit/Refactor/Convert to objective-C ARC, then check off the files you don't want to be converted. I find this way the same as using the compiler flag above.

How to sort an array based on the length of each element?

#created a sorting function to sort by length of elements of list
def sort_len(a):
    num = len(a)
    d = {}
    i = 0
    while i<num:
        d[i] = len(a[i])
        i += 1
    b = list(d.values())
    b.sort()
    c = []
    for i in b:
        for j in range(num):
            if j in list(d.keys()):
                if d[j] == i:
                    c.append(a[j])
                    d.pop(j)
    return c

How to escape double quotes in a title attribute

It may work with any character from the HTML Escape character list, but I had the same problem with a Java project. I used StringEscapeUtils.escapeHTML("Testing \" <br> <p>") and the title was <a href=".." title="Test&quot; &lt;br&gt; &lt;p&gt;">Testing</a>.

It only worked for me when I changed the StringEscapeUtils to StringEscapeUtils.escapeJavascript("Testing \" <br> <p>") and it worked in every browser.

PHP - warning - Undefined property: stdClass - fix?

Depending on whether you're looking for a member or method, you can use either of these two functions to see if a member/method exists in a particular object:

http://php.net/manual/en/function.method-exists.php

http://php.net/manual/en/function.property-exists.php

More generally if you want all of them:

http://php.net/manual/en/function.get-object-vars.php

Programmatically relaunch/recreate an activity?

Also depending on your situation, you may need getActivity().recreate(); instead of just recreate().

For example, you should use it if you are doing recreate() in the class which has been created inside class of activity.

onclick event pass <li> id or value

<li>s don't have a value - only form inputs do. In fact, you're not supposed to even include the value attribute in the HTML for <li>s.

You can rely on .innerHTML instead:

getPaging(this.innerHTML)

Or maybe the id:

getPaging(this.id);

However, it's easier (and better practice) to add the click handlers from JavaScript code, and not include them in the HTML. Seeing as you're already using jQuery, this can easily be done by changing your HTML to:

<li class="clickMe">1</li>
<li class="clickMe">2</li>

And use the following JavaScript:

$(function () {
    $('.clickMe').click(function () {
        var str = $(this).text();
        $('#loading-content').load('dataSearch.php?' + str, hideLoader);
    });
});

This will add the same click handler to all your <li class="clickMe">s, without requiring you to duplicate your onclick="getPaging(this.value)" code for each of them.

Search for all occurrences of a string in a mysql database

Not an elegant solution, but you could achieve it with a nested looping structure

// select tables from database and store in an array

// loop through the array
foreach table in database
{
    // select columns in the table and store in an array

    // loop through the array
    foreach column in table
    {
        // select * from table where column = url
    }
}

You could probably speed this up by checking which columns contain strings while building your column array, and also by combining all the columns per table in one giant, comma-separated WHERE clause.

Increment a Integer's int value?

AtomicInteger

Maybe this is of some worth also: there is a Java class called AtomicInteger.

This class has some useful methods like addAndGet(int delta) or incrementAndGet() (and their counterparts) which allow you to increment/decrement the value of the same instance. Though the class is designed to be used in the context of concurrency, it's also quite useful in other scenarios and probably fits your need.

final AtomicInteger count = new AtomicInteger( 0 ) ;
…
count.incrementAndGet();  // Ignoring the return value. 

Android Error - Open Failed ENOENT

With sdk, you can't write to the root of internal storage. This cause your error.

Edit :

Based on your code, to use internal storage with sdk:

final File dir = new File(context.getFilesDir() + "/nfs/guille/groce/users/nicholsk/workspace3/SQLTest");
dir.mkdirs(); //create folders where write files
final File file = new File(dir, "BlockForTest.txt");

How to use DISTINCT and ORDER BY in same SELECT statement?

2) Order by CreationDate is very important

The original results indicated that "test3" had multiple results...

It's very easy to start using MAX all the time to remove duplicates in Group By's... and forget or ignore what the underlying question is...

The OP presumably realised that using MAX was giving him the last "created" and using MIN would give the first "created"...

SQL Server 2008 R2 can't connect to local database in Management Studio

Your "SQL Server Browser" service has to be started too.

Browse to Computer Management > Services. how to browse to computer management

Find find "SQL Server Browser"

  1. set it to Automatic
  2. and also Manually start it (2)

how to edit sql server browser properties and start it

Hope it helps.

error LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStartup

If you are using Visual Studio. The reason you might be recieving this error may be because you originally created a new header file.h and then renamed it to file.cpp where you placed your main() function.

To fix the issue right click file.cpp -> click Properties go to
Configuration Properties -> General ->Item Type and change its value to C/C++ compiler instead of C/C++ header.

What does Docker add to lxc-tools (the userspace LXC tools)?

From the Docker FAQ:

Docker is not a replacement for lxc. "lxc" refers to capabilities of the linux kernel (specifically namespaces and control groups) which allow sandboxing processes from one another, and controlling their resource allocations.

On top of this low-level foundation of kernel features, Docker offers a high-level tool with several powerful functionalities:

  • Portable deployment across machines. Docker defines a format for bundling an application and all its dependencies into a single object which can be transferred to any docker-enabled machine, and executed there with the guarantee that the execution environment exposed to the application will be the same. Lxc implements process sandboxing, which is an important pre-requisite for portable deployment, but that alone is not enough for portable deployment. If you sent me a copy of your application installed in a custom lxc configuration, it would almost certainly not run on my machine the way it does on yours, because it is tied to your machine's specific configuration: networking, storage, logging, distro, etc. Docker defines an abstraction for these machine-specific settings, so that the exact same docker container can run - unchanged - on many different machines, with many different configurations.

  • Application-centric. Docker is optimized for the deployment of applications, as opposed to machines. This is reflected in its API, user interface, design philosophy and documentation. By contrast, the lxc helper scripts focus on containers as lightweight machines - basically servers that boot faster and need less ram. We think there's more to containers than just that.

  • Automatic build. Docker includes a tool for developers to automatically assemble a container from their source code, with full control over application dependencies, build tools, packaging etc. They are free to use make, maven, chef, puppet, salt, debian packages, rpms, source tarballs, or any combination of the above, regardless of the configuration of the machines.

  • Versioning. Docker includes git-like capabilities for tracking successive versions of a container, inspecting the diff between versions, committing new versions, rolling back etc. The history also includes how a container was assembled and by whom, so you get full traceability from the production server all the way back to the upstream developer. Docker also implements incremental uploads and downloads, similar to "git pull", so new versions of a container can be transferred by only sending diffs.

  • Component re-use. Any container can be used as an "base image" to create more specialized components. This can be done manually or as part of an automated build. For example you can prepare the ideal python environment, and use it as a base for 10 different applications. Your ideal postgresql setup can be re-used for all your future projects. And so on.

  • Sharing. Docker has access to a public registry (https://registry.hub.docker.com/) where thousands of people have uploaded useful containers: anything from redis, couchdb, postgres to irc bouncers to rails app servers to hadoop to base images for various distros. The registry also includes an official "standard library" of useful containers maintained by the docker team. The registry itself is open-source, so anyone can deploy their own registry to store and transfer private containers, for internal server deployments for example.

  • Tool ecosystem. Docker defines an API for automating and customizing the creation and deployment of containers. There are a huge number of tools integrating with docker to extend its capabilities. PaaS-like deployment (Dokku, Deis, Flynn), multi-node orchestration (maestro, salt, mesos, openstack nova), management dashboards (docker-ui, openstack horizon, shipyard), configuration management (chef, puppet), continuous integration (jenkins, strider, travis), etc. Docker is rapidly establishing itself as the standard for container-based tooling.

I hope this helps!

Does Python have an argc argument?

In python a list knows its length, so you can just do len(sys.argv) to get the number of elements in argv.

Prevent browser caching of AJAX call result

I use new Date().getTime(), which will avoid collisions unless you have multiple requests happening within the same millisecond:

$.get('/getdata?_=' + new Date().getTime(), function(data) {
    console.log(data); 
});

Edit: This answer is several years old. It still works (hence I haven't deleted it), but there are better/cleaner ways of achieving this now. My preference is for this method, but this answer is also useful if you want to disable caching for every request during the lifetime of a page.

How to fetch Java version using single line command in Linux

You can use --version and in that case it's not required to redirect to stdout

java --version | head -1 | cut -f2 -d' '

From java help

-version      print product version to the error stream and exit
--version     print product version to the output stream and exit

How can you determine a point is between two other points on a line segment?

The scalar product between (c-a) and (b-a) must be equal to the product of their lengths (this means that the vectors (c-a) and (b-a) are aligned and with the same direction). Moreover, the length of (c-a) must be less than or equal to that of (b-a). Pseudocode:

# epsilon = small constant

def isBetween(a, b, c):
    lengthca2  = (c.x - a.x)*(c.x - a.x) + (c.y - a.y)*(c.y - a.y)
    lengthba2  = (b.x - a.x)*(b.x - a.x) + (b.y - a.y)*(b.y - a.y)
    if lengthca2 > lengthba2: return False
    dotproduct = (c.x - a.x)*(b.x - a.x) + (c.y - a.y)*(b.y - a.y)
    if dotproduct < 0.0: return False
    if abs(dotproduct*dotproduct - lengthca2*lengthba2) > epsilon: return False 
    return True

How do you beta test an iphone app?

Using testflight :

1) create the ipa file by development certificate

2) upload the ipa file on testflight

3) Now, to identify the device to be tested on , add the device id on apple account and refresh your development certificate. Download the updated certificate and upload it on testflight website. Check the device id you are getting.

4) Now email the ipa file to the testers.

5) While downloading the ipa file, if the testers are not getting any warnings, this means the device token + provisioning profile has been verified. So, the testers can now download the ipa file on device and do the testing job...

How to link external javascript file onclick of button

It is totally possible, i did something similar based on the example of Mike Sav. That's the html page and ther shoul be an external test.js file in the same folder

example.html:

<html>
<button type="button" value="Submit" onclick="myclick()" >
Click here~!
<div id='mylink'></div>
</button>
<script type="text/javascript">
function myclick(){
    var myLink = document.getElementById('mylink');
    myLink.onclick = function(){
            var script = document.createElement("script");
            script.type = "text/javascript";
            script.src = "./test.js"; 
            document.getElementsByTagName("head")[0].appendChild(script);
            return false;
    }
    document.getElementById('mylink').click();
}
</script>
</html>

test.js:

alert('hello world')

Useful example of a shutdown hook in Java?

Shutdown Hooks are unstarted threads that are registered with Runtime.addShutdownHook().JVM does not give any guarantee on the order in which shutdown hooks are started.For more info refer http://techno-terminal.blogspot.in/2015/08/shutdown-hooks.html

Use space as a delimiter with cut command

You can also say:

cut -d\  -f 2

Note that there are two spaces after the backslash.