Programs & Examples On #Uploader

Could not find module "@angular-devkit/build-angular"

In my case, the issue is, because of missing dependencies. The dependencies are missing, because I've forgotten to call:

npm install

After calling the above command, all required dependencies are loaded in node_modules, and that is no more issue

File Upload In Angular?

In Angular 2+, it is very important to leave the Content-Type empty. If you set the 'Content-Type' to 'multipart/form-data' the upload will not work !

upload.component.html

<input type="file" (change)="fileChange($event)" name="file" />

upload.component.ts

export class UploadComponent implements OnInit {
    constructor(public http: Http) {}

    fileChange(event): void {
        const fileList: FileList = event.target.files;
        if (fileList.length > 0) {
            const file = fileList[0];

            const formData = new FormData();
            formData.append('file', file, file.name);

            const headers = new Headers();
            // It is very important to leave the Content-Type empty
            // do not use headers.append('Content-Type', 'multipart/form-data');
            headers.append('Authorization', 'Bearer ' + 'eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9....');
            const options = new RequestOptions({headers: headers});

            this.http.post('https://api.mysite.com/uploadfile', formData, options)
                 .map(res => res.json())
                 .catch(error => Observable.throw(error))
                 .subscribe(
                     data => console.log('success'),
                     error => console.log(error)
                 );
        }
    }
}

React eslint error missing in props validation

Issue: 'id1' is missing in props validation, eslintreact/prop-types

<div id={props.id1} >
    ...
</div>

Below solution worked, in a function component:

let { id1 } = props;

<div id={id1} >
    ...
</div>

Hope that helps.

Reading Excel file using node.js

You can use read-excel-file npm.

In that, you can specify JSON Schema to convert XLSX into JSON Format.

const readXlsxFile = require('read-excel-file/node');

const schema = {
    'Segment': {
        prop: 'Segment',
        type: String
    },
    'Country': {
        prop: 'Country',
        type: String
    },
    'Product': {
        prop: 'Product',
        type: String
    }
}

readXlsxFile('sample.xlsx', { schema }).then(({ rows, errors }) => {
    console.log(rows);
});

File uploading with Express 4.0: req.files undefined

Here is what i found googling around:

var fileupload = require("express-fileupload");
app.use(fileupload());

Which is pretty simple mechanism for uploads

app.post("/upload", function(req, res)
{
    var file;

    if(!req.files)
    {
        res.send("File was not found");
        return;
    }

    file = req.files.FormFieldName;  // here is the field name of the form

    res.send("File Uploaded");


});

Node.js: what is ENOSPC error and how to solve?

On Linux, this is likely to be a limit on the number of file watches.

The development server uses inotify to implement hot-reloading. The inotify API allows the development server to watch files and be notified when they change.

The default inotify file watch limit varies from distribution to distribution (8192 on Fedora). The needs of the development server often exceeds this limit.

The best approach is to try increasing the file watch limit temporarily, then making that a permanent configuration change if you're happy with it. Note, though, that this changes your entire system's configuration, not just node.

To view your current limit:

sysctl fs.inotify.max_user_watches

To temporarily set a new limit:

# this limit will revert after reset
sudo sysctl fs.inotify.max_user_watches=524288
sudo sysctl -p
# now restart the server and see if it works

To set a permanent limit:

echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf
sudo sysctl -p

How to make a simple image upload using Javascript/HTML

Here's a simple example with no jQuery. Use URL.createObjectURL, which

creates a DOMString containing a URL representing the object given in the parameter

Then, you can simply set the src of the image to that url:

_x000D_
_x000D_
window.addEventListener('load', function() {
  document.querySelector('input[type="file"]').addEventListener('change', function() {
      if (this.files && this.files[0]) {
          var img = document.querySelector('img');
          img.onload = () => {
              URL.revokeObjectURL(img.src);  // no longer needed, free memory
          }

          img.src = URL.createObjectURL(this.files[0]); // set src to blob url
      }
  });
});
_x000D_
<input type='file' />
<br><img id="myImg" src="#">
_x000D_
_x000D_
_x000D_

Using Spring MVC Test to unit test multipart POST request

The method MockMvcRequestBuilders.fileUpload is deprecated use MockMvcRequestBuilders.multipart instead.

This is an example:

import static org.hamcrest.CoreMatchers.containsString;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mockito;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
import org.springframework.boot.test.mock.mockito.MockBean;
import org.springframework.mock.web.MockMultipartFile;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.ResultActions;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.result.MockMvcResultHandlers;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.multipart.MultipartFile;


/**
 * Unit test New Controller.
 *
 */
@RunWith(SpringRunner.class)
@WebMvcTest(NewController.class)
public class NewControllerTest {

    private MockMvc mockMvc;

    @Autowired
    WebApplicationContext wContext;

    @MockBean
    private NewController newController;

    @Before
    public void setup() {
        this.mockMvc = MockMvcBuilders.webAppContextSetup(wContext)
                   .alwaysDo(MockMvcResultHandlers.print())
                   .build();
    }

   @Test
    public void test() throws Exception {
       // Mock Request
        MockMultipartFile jsonFile = new MockMultipartFile("test.json", "", "application/json", "{\"key1\": \"value1\"}".getBytes());

        // Mock Response
        NewControllerResponseDto response = new NewControllerDto();
        Mockito.when(newController.postV1(Mockito.any(Integer.class), Mockito.any(MultipartFile.class))).thenReturn(response);

        mockMvc.perform(MockMvcRequestBuilders.multipart("/fileUpload")
                .file("file", jsonFile.getBytes())
                .characterEncoding("UTF-8"))
        .andExpect(status().isOk());

    }

}

Fatal error: Namespace declaration statement has to be the very first statement in the script in

There is a mistake in its source. Check out its source if you may. It reads like this

<?php
    class BulletProofException extends Exception{}

    namespace BulletProof;
    ....

That is insane. Personally, I'd say the code is well documented, and elegant, but the author missed a simple point; he declared the namespace within the class. Namespace whenever used should be the first statement.

Too bad I am not in Github; could have pulled a request otherwise :(

JQuery Validate input file type

One the elements are added, use the rules method to add the rules

//bug fixed thanks to @Sparky
$('input[name^="fileupload"]').each(function () {
    $(this).rules('add', {
        required: true,
        accept: "image/jpeg, image/pjpeg"
    })
})

Demo: Fiddle


Update

var filenumber = 1;
$("#AddFile").click(function () { //User clicks button #AddFile
    var $li = $('<li><input type="file" name="FileUpload' + filenumber + '" id="FileUpload' + filenumber + '" required=""/> <a href="#" class="RemoveFileUpload">Remove</a></li>').prependTo("#FileUploader");

    $('#FileUpload' + filenumber).rules('add', {
        required: true,
        accept: "image/jpeg, image/pjpeg"
    })

    filenumber++;
    return false;
});

YouTube API to fetch all videos on a channel

First, you need to get the ID of the playlist that represents the uploads from the user/channel:

https://developers.google.com/youtube/v3/docs/channels/list#try-it

You can specify the username with the forUsername={username} param, or specify mine=true to get your own (you need to authenticate first). Include part=contentDetails to see the playlists.

GET https://www.googleapis.com/youtube/v3/channels?part=contentDetails&forUsername=jambrose42&key={YOUR_API_KEY}

In the result "relatedPlaylists" will include "likes" and "uploads" playlists. Grab that "upload" playlist ID. Also note the "id" is your channelID for future reference.

Next, get a list of videos in that playlist:

https://developers.google.com/youtube/v3/docs/playlistItems/list#try-it

Just drop in the playlistId!

GET https://www.googleapis.com/youtube/v3/playlistItems?part=snippet%2CcontentDetails&maxResults=50&playlistId=UUpRmvjdu3ixew5ahydZ67uA&key={YOUR_API_KEY}

Can someone explain how to implement the jQuery File Upload plugin?

Check out the Image drag and drop uploader with image preview using dropper jquery plugin.

HTML

<div class="target" width="78" height="100"><img /></div>

JS

$(".target").dropper({
    action: "upload.php",

}).on("start.dropper", onStart);
function onStart(e, files){
console.log(files[0]);

    image_preview(files[0].file).then(function(res){
$('.dropper-dropzone').empty();
//$('.dropper-dropzone').css("background-image",res.data);
 $('#imgPreview').remove();        
$('.dropper-dropzone').append('<img id="imgPreview"/><span style="display:none">Drag and drop files or click to select</span>');
var widthImg=$('.dropper-dropzone').attr('width');
        $('#imgPreview').attr({width:widthImg});
    $('#imgPreview').attr({src:res.data});

    })

}

function image_preview(file){
    var def = new $.Deferred();
    var imgURL = '';
    if (file.type.match('image.*')) {
        //create object url support
        var URL = window.URL || window.webkitURL;
        if (URL !== undefined) {
            imgURL = URL.createObjectURL(file);
            URL.revokeObjectURL(file);
            def.resolve({status: 200, message: 'OK', data:imgURL, error: {}});
        }
        //file reader support
        else if(window.File && window.FileReader)
        {
            var reader = new FileReader();
            reader.readAsDataURL(file);
            reader.onloadend = function () {
                imgURL = reader.result;
                def.resolve({status: 200, message: 'OK', data:imgURL, error: {}});
            }
        }
        else {
            def.reject({status: 1001, message: 'File uploader not supported', data:imgURL, error: {}});
        }
    }
    else
        def.reject({status: 1002, message: 'File type not supported', error: {}});
    return def.promise();
}

$('.dropper-dropzone').mouseenter(function() {
 $( '.dropper-dropzone>span' ).css("display", "block");
});

$('.dropper-dropzone').mouseleave(function() {
 $( '.dropper-dropzone>span' ).css("display", "none");
});

CSS

.dropper-dropzone{
    width:78px;
padding:3px;
    height:100px;
position: relative;
}
.dropper-dropzone>img{
    width:78px;
    height:100px;
margin-top=0;
}

.dropper-dropzone>span {
    position: absolute;
    right: 10px;
    top: 20px;
color:#ccc;


}

.dropper .dropper-dropzone{

padding:3px !important    
}

Demo Jsfiddle

How to make <input type="file"/> accept only these types?

for powerpoint and pdf files:

<html>
<input type="file" placeholder="Do you have a .ppt?" name="pptfile" id="pptfile" accept="application/pdf,application/vnd.ms-powerpoint,application/vnd.openxmlformats-officedocument.presentationml.slideshow,application/vnd.openxmlformats-officedocument.presentationml.presentation"/>
</html>

ORA-00984: column not allowed here

Replace double quotes with single ones:

INSERT
INTO    MY.LOGFILE
        (id,severity,category,logdate,appendername,message,extrainfo)
VALUES  (
       'dee205e29ec34',
       'FATAL',
       'facade.uploader.model',
       '2013-06-11 17:16:31',
       'LOGDB',
       NULL,
       NULL
       )

In SQL, double quotes are used to mark identifiers, not string constants.

coercing to Unicode: need string or buffer, NoneType found when rendering in django admin

First, check that whatever you are returning via unicode is a String.

If it is not a string you can change it to a string like this (where self.id is an integer)

def __unicode__(self):
    return '%s' % self.id

following which, if it still doesn't work, restart your ./manage.py shell for the changes to take effect and try again. It should work.

Best Regards

how to get files from <input type='file' .../> (Indirect) with javascript

Based on Ray Nicholus's answer :

inputElement.onchange = function(event) {
   var fileList = inputElement.files;
   //TODO do something with fileList.  
}

using this will also work :

inputElement.onchange = function(event) {
   var fileList = event.target.files;
   //TODO do something with fileList.  
}

Jquery and HTML FormData returns "Uncaught TypeError: Illegal invocation"

In my case, there was a mistake in the list of the parameters was not well formed. So make sure the parameters are well formed. For e.g. correct format of parameters

data: {'reporter': reporter,'partner': partner,'product': product}

Using curl to upload POST data with files

The issue that lead me here turned out to be a basic user error - I wasn't including the @ sign in the path of the file and so curl was posting the path/name of the file rather than the contents. The Content-Length value was therefore 8 rather than the 479 I expected to see given the legnth of my test file.

The Content-Length header will be automatically calculated when curl reads and posts the file.

curl -i -H "Content-Type: application/xml" --data "@test.xml" -v -X POST https://<url>/<uri/

... < Content-Length: 479 ...

Posting this here to assist other newbies in future.

Setting PHP tmp dir - PHP upload not working

create php-file with:

<?php
    print shell_exec( 'whoami' );
?>

or

<?php echo exec('whoami'); ?>

try the output in your web-browser. if the output is not your user example: www-data then proceed to next step

open as root:

/etc/apache2/envvars

look for these lines:

export APACHE_RUN_USER=user-name

export APACHE_RUN_GROUP=group-name

example:

export APACHE_RUN_USER=www-data

export APACHE_RUN_GROUP=www-data

where:

username = your username that has access to the folder you are using group = group you've given read+write+execute access

change it to:

export APACHE_RUN_USER="username"

export APACHE_RUN_GROUP="group"

if your user have no access yet:

sudo chmod 775 -R "directory of folder you want to give r/w/x access"

Why is json_encode adding backslashes?

Can anyone tell me why json_encode adds slashes?

Forward slash characters can cause issues (when preceded by a < it triggers the SGML rules for "end of script element") when embedded in an HTML script element. They are escaped as a precaution.

Because when I try do use jQuery.parseJSON(response); in my js script, it returns null. So my guess it has something to do with the slashes.

It doesn't. In JSON "/" and "\/" are equivalent.

The JSON you list in the question is valid (you can test it with jsonlint). Your problem is likely to do with what happens to it between json_encode and parseJSON.

If a folder does not exist, create it

You can create the path if it doesn't exist yet with a method like the following:

using System.IO;

private void CreateIfMissing(string path)
{
  bool folderExists = Directory.Exists(Server.MapPath(path));
  if (!folderExists)
    Directory.CreateDirectory(Server.MapPath(path));
}

Clear text area

I agree with @Jakub Arnold's answer. The problem should be somewhere else. I could not figure out the problem but found a work around.

Wrap your concerned element with a parent element and cause its html to create a new element with the id you are concerned with. See below

<div id="theParent">
    <div id="vinanghinguyen_images_bbocde"></div>
</div>

'onSelect'    : function(event,ID,fileObj) {
 $("#theParent").html("<div id='vinanghinguyen_images_bbocde'></div>");
 $("#vinanghinguyen_result").hide();
 $(".uploadifyQueue").height(315);
}

Android file chooser

EDIT (02 Jan 2012):

I created a small open source Android Library Project that streamlines this process, while also providing a built-in file explorer (in case the user does not have one present). It's extremely simple to use, requiring only a few lines of code.

You can find it at GitHub: aFileChooser.


ORIGINAL

If you want the user to be able to choose any file in the system, you will need to include your own file manager, or advise the user to download one. I believe the best you can do is look for "openable" content in an Intent.createChooser() like this:

private static final int FILE_SELECT_CODE = 0;

private void showFileChooser() {
    Intent intent = new Intent(Intent.ACTION_GET_CONTENT); 
    intent.setType("*/*"); 
    intent.addCategory(Intent.CATEGORY_OPENABLE);

    try {
        startActivityForResult(
                Intent.createChooser(intent, "Select a File to Upload"),
                FILE_SELECT_CODE);
    } catch (android.content.ActivityNotFoundException ex) {
        // Potentially direct the user to the Market with a Dialog
        Toast.makeText(this, "Please install a File Manager.", 
                Toast.LENGTH_SHORT).show();
    }
}

You would then listen for the selected file's Uri in onActivityResult() like so:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    switch (requestCode) {
        case FILE_SELECT_CODE:
        if (resultCode == RESULT_OK) {
            // Get the Uri of the selected file 
            Uri uri = data.getData();
            Log.d(TAG, "File Uri: " + uri.toString());
            // Get the path
            String path = FileUtils.getPath(this, uri);
            Log.d(TAG, "File Path: " + path);
            // Get the file instance
            // File file = new File(path);
            // Initiate the upload
        }
        break;
    }
    super.onActivityResult(requestCode, resultCode, data);
}

The getPath() method in my FileUtils.java is:

public static String getPath(Context context, Uri uri) throws URISyntaxException {
    if ("content".equalsIgnoreCase(uri.getScheme())) {
        String[] projection = { "_data" };
        Cursor cursor = null;

        try {
            cursor = context.getContentResolver().query(uri, projection, null, null, null);
            int column_index = cursor.getColumnIndexOrThrow("_data");
            if (cursor.moveToFirst()) {
                return cursor.getString(column_index);
            }
        } catch (Exception e) {
            // Eat it
        }
    }
    else if ("file".equalsIgnoreCase(uri.getScheme())) {
        return uri.getPath();
    }

    return null;
} 

Convert Data URI to File then append to FormData

After playing around with a few things, I managed to figure this out myself.

First of all, this will convert a dataURI to a Blob:

function dataURItoBlob(dataURI) {
    // convert base64/URLEncoded data component to raw binary data held in a string
    var byteString;
    if (dataURI.split(',')[0].indexOf('base64') >= 0)
        byteString = atob(dataURI.split(',')[1]);
    else
        byteString = unescape(dataURI.split(',')[1]);

    // separate out the mime component
    var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];

    // write the bytes of the string to a typed array
    var ia = new Uint8Array(byteString.length);
    for (var i = 0; i < byteString.length; i++) {
        ia[i] = byteString.charCodeAt(i);
    }

    return new Blob([ia], {type:mimeString});
}

From there, appending the data to a form such that it will be uploaded as a file is easy:

var dataURL = canvas.toDataURL('image/jpeg', 0.5);
var blob = dataURItoBlob(dataURL);
var fd = new FormData(document.forms[0]);
fd.append("canvasImage", blob);

python exception message capturing

Updating this to something simpler for logger (works for both python 2 and 3). You do not need traceback module.

import logging

logger = logging.Logger('catch_all')

def catchEverythingInLog():
    try:
        ... do something ...
    except Exception as e:
        logger.error(e, exc_info=True)
        ... exception handling ...

This is now the old way (though still works):

import sys, traceback

def catchEverything():
    try:
        ... some operation(s) ...
    except:
        exc_type, exc_value, exc_traceback = sys.exc_info()
        ... exception handling ...

exc_value is the error message.

Only variables should be passed by reference

Just as you can't index the array immediately, you can't call end on it either. Assign it to a variable first, then call end.

$basenameAndExtension = explode('.', $file_name);
$ext = end($basenameAndExtension);

jQuery change method on input type="file"

is the ajax uploader refreshing your input element? if so you should consider using .live() method.

 $('#imageFile').live('change', function(){ uploadFile(); });

update:

from jQuery 1.7+ you should use now .on()

 $(parent_element_selector_here or document ).on('change','#imageFile' , function(){ uploadFile(); });

How can you integrate a custom file browser/uploader with CKEditor?

This is the approach I've used. It's quite straightforward, and works just fine.

In the CK editor root directory there is a file named config.js

I added this (you don't need the querystring stuff, this is just for our file manager). I also included some skinning and changing of the default buttons shown:

CKEDITOR.editorConfig = function(config) {

    config.skin = 'v2';
    config.startupFocus = false;
    config.filebrowserBrowseUrl = '/admin/content/filemanager.aspx?path=Userfiles/File&editor=FCK';
    config.filebrowserImageBrowseUrl = '/admin/content/filemanager.aspx?type=Image&path=Userfiles/Image&editor=FCK';
    config.toolbar_Full =
    [
        ['Source', '-', 'Preview', '-'],
        ['Cut', 'Copy', 'Paste', 'PasteText', 'PasteFromWord', '-', 'Print', 'SpellChecker'], //, 'Scayt' 
        ['Undo', 'Redo', '-', 'Find', 'Replace', '-', 'SelectAll', 'RemoveFormat'],
        '/',
        ['Bold', 'Italic', 'Underline', 'Strike', '-', 'Subscript', 'Superscript'],
        ['NumberedList', 'BulletedList', '-', 'Outdent', 'Indent', 'Blockquote'],
        ['JustifyLeft', 'JustifyCenter', 'JustifyRight', 'JustifyBlock'],
        ['Link', 'Unlink', 'Anchor'],
        ['Image', 'Flash', 'Table', 'HorizontalRule', 'SpecialChar'],
        '/',
        ['Styles', 'Format', 'Templates'],
        ['Maximize', 'ShowBlocks']
    ];

};

Then, our file manager calls this:

opener.SetUrl('somefilename');

How to call a Web Service Method?

The current way to do this is by using the "Add Service Reference" command. If you specify "TestUploaderWebService" as the service reference name, that will generate the type TestUploaderWebService.Service1. That class will have a method named GetFileListOnWebServer, which will return an array of strings (you can change that to be a list of strings if you like). You would use it like this:

string[] files = null;
TestUploaderWebService.Service1 proxy = null;
bool success = false;
try
{
    proxy = new TestUploaderWebService.Service1();
    files = proxy.GetFileListOnWebServer();
    proxy.Close();
    success = true;
}
finally
{
    if (!success)
    {
        proxy.Abort();
    }
}

P.S. Tell your instructor to look at "Microsoft: ASMX Web Services are a “Legacy Technology”", and ask why he's teaching out of date technology.

Dynamically set value of a file input

I am working on an angular js app, andhavecome across a similar issue. What i did was display the image from the db, then created a button to remove or keep the current image. If the user decided to keep the current image, i changed the ng-submit attribute to another function whihc doesnt require image validation, and updated the record in the db without touching the original image path name. The remove image function also changed the ng-submit attribute value back to a function that submits the form and includes image validation and upload. Also a bit of javascript to slide the into view to upload a new image.

Upload Progress Bar in PHP

You would need to use Javascript to create a progress bar. A simple Google search led me to this article: WebAppers Simple Javascript Progress Bar with CSS.

Dojo File Upload Progress Bar Widget is another option using the Dojo Javascript framework.

EDIT: Assuming your uploading a large number of images (such as a photo album), and POSTing them to your PHP script, you could use javascript to read the results back from the post and update the progress bar based on the number of images uploaded / total number of images. This has the side effect of only updating after each post has completed. Check out here for some info on how to post with JS.

Filter Extensions in HTML form upload

The accept attribute specifies a comma-separated list of content types (MIME types) that the target of the form will process correctly. Unfortunately this attribute is ignored by all the major browsers, so it does not affect the browser's file dialog in any way.

Format numbers in thousands (K) in Excel

The examples above use a 'K' an uppercase k used to represent kilo or 1000. According to wiki, kilo or 1000's should be represented in lower case. So, rather than £300K, use £300k or in a code example :-

[>=1000]£#,##0,"k";[red][<=-1000]-£#,##0,"k";0

Unable to create Android Virtual Device

This can happen when:

  • You have multiple copies of the Android SDK installed on your machine. You may be updating the available images and devices for one copy of the Android SDK, and trying to debug or run your application in another.

    If you're using Eclipse, take a look at your "Preferences | Android | SDK Location". Make sure it's the path you expect. If not, change the path to point to where you think the Android SDK is installed.

  • You don't have an Android device setup in your emulator as detailed in other answers on this page.

seek() function?

The seek function expect's an offset in bytes.

Ascii File Example:

So if you have a text file with the following content:

simple.txt

abc

You can jump 1 byte to skip over the first character as following:

fp = open('simple.txt', 'r')
fp.seek(1)
print fp.readline()
>>> bc

Binary file example gathering width :

fp = open('afile.png', 'rb')
fp.seek(16)
print 'width: {0}'.format(struct.unpack('>i', fp.read(4))[0])
print 'height: ', struct.unpack('>i', fp.read(4))[0]

Note: Once you call read you are changing the position of the read-head, which act's like seek.

How to hash some string with sha256 in Java?

In Java, MessageDigest class is used to calculate cryptographic hashing value. This class provides cryptographic hash function ( MD5, SHA-1 and SHA-256) to find hash value of text.

Code example for using SHA-256 algorithm.

public void printHash(String str) throws NoSuchAlgorithmException {

MessageDigest md=MessageDigest.getInstance("SHA-256");

byte[] sha256=md.digest(str.getBytes(StandardCharsets.UTF_8));

   for(byte b : sha256){

      System.out.printf("%02x",b);

  }
}

How to create a dynamic array of integers

dynamically allocate some memory using new:

int* array = new int[SIZE];

error: invalid initialization of non-const reference of type ‘int&’ from an rvalue of type ‘int’

C++03 3.10/1 says: "Every expression is either an lvalue or an rvalue." It's important to remember that lvalueness versus rvalueness is a property of expressions, not of objects.

Lvalues name objects that persist beyond a single expression. For example, obj , *ptr , ptr[index] , and ++x are all lvalues.

Rvalues are temporaries that evaporate at the end of the full-expression in which they live ("at the semicolon"). For example, 1729 , x + y , std::string("meow") , and x++ are all rvalues.

The address-of operator requires that its "operand shall be an lvalue". if we could take the address of one expression, the expression is an lvalue, otherwise it's an rvalue.

 &obj; //  valid
 &12;  //invalid

Allow all remote connections, MySQL

GRANT ALL ON *.* to user@'%' IDENTIFIED BY 'password'; 

Will allow a specific user to log on from anywhere.

It's bad because it removes some security control, i.e. if an account is compromised.

How to obtain the number of CPUs/cores in Linux from the command line?

You can also use Python! To get the number of physical cores:

$ python -c "import psutil; print(psutil.cpu_count(logical=False))"
4

To get the number of hyperthreaded cores:

$ python -c "import psutil; print(psutil.cpu_count(logical=True))"
8

Safely casting long to int in Java

A new method has been added with Java 8 to do just that.

import static java.lang.Math.toIntExact;

long foo = 10L;
int bar = toIntExact(foo);

Will throw an ArithmeticException in case of overflow.

See: Math.toIntExact(long)

Several other overflow safe methods have been added to Java 8. They end with exact.

Examples:

  • Math.incrementExact(long)
  • Math.subtractExact(long, long)
  • Math.decrementExact(long)
  • Math.negateExact(long),
  • Math.subtractExact(int, int)

Cannot insert explicit value for identity column in table 'table' when IDENTITY_INSERT is set to OFF

There is pre-mentioned OperationId in your query which should not be there as it is auto increamented

Insert table(OperationID,OpDescription,FilterID)
values (20,'Hierachy Update',1)

so your query will be

Insert table(OpDescription,FilterID)
values ('Hierachy Update',1)

Detecting a mobile browser

Depends on the use case. All mobile devices require a battery. If what you're after is compute power without draining the battery use the Battery Status API:

navigator.getBattery().then(battery => {
  battery.charging ? 'charging' : 'not charging';
});

If what you're looking for is presentational use matchMedia, which returns a Boolean value:

if (window.matchMedia("(min-width: 400px)").matches) {
  /* the viewport is at least 400 pixels wide */
} else {
  /* the viewport is less than 400 pixels wide */
}

Or combine them for an even better user experience on tablet devices.

Linker command failed with exit code 1 - duplicate symbol __TMRbBp

I had similar kind of problem when I added a framework to my project.

I have resolved the issue by removing the framework and again adding the framework to the project by dragging and dropping the framework file to the projects frameworks folder and selecting the Copy items if needed option.enter image description here

How to get PID by process name?

You can use psutil package:

Install

pip install psutil

Usage:

import psutil

process_name = "chrome"
pid = None

for proc in psutil.process_iter():
    if process_name in proc.name():
       pid = proc.pid

How to add an image in the title bar using html?

I tried in my angular7 project by writing these lines and worked.

<link rel="icon" type="image/x-icon" href="filepath/filename.ico">

please be noted that the image file should be in icon format (.ico)

How to count check-boxes using jQuery?

The following code worked for me.

$('input[name="chkGender[]"]:checked').length;

How to implement the Java comparable interface?

Possible alternative from the source code of Integer.compare method which requires API Version 19 is :

public int compareTo(Animal other) { return Integer.valueOf(this.year_discovered).compareTo(other.year_discovered); }

This alternative does not require you to use API version 19.

Build fat static library (device + simulator) using Xcode and SDK 4+

I've made this into an Xcode 4 template, in the same vein as Karl's static framework template.

I found that building static frameworks (instead of plain static libraries) was causing random crashes with LLVM, due to an apparent linker bug - so, I guess static libraries are still useful!

MySQL Database won't start in XAMPP Manager-osx

check the err log on your /Applications/XAMPP/xamppfiles/var/mysql/ with filename like your_machine_name.local.err, if you find something like: "Attempted to open a previously opened tablespace. Previous tablespace ... uses space ID"

the following works for me:

edit file:

/Applications/XAMPP/xamppfiles/etc/my.cnf

find the [mysqld] section, add one line:

innodb_force_recovery = 1

then run

sudo /Applications/XAMPP/bin/mysql.server start

everything is ok again.

and then the last step:

edit the my.cnf again and remove the line you just added :

innodb_force_recovery = 1

and restart mysql again. Otherwise all your tables will be read only

How do I determine k when using k-means clustering?

If you use MATLAB, any version since 2013b that is, you can make use of the function evalclusters to find out what should the optimal k be for a given dataset.

This function lets you choose from among 3 clustering algorithms - kmeans, linkage and gmdistribution.

It also lets you choose from among 4 clustering evaluation criteria - CalinskiHarabasz, DaviesBouldin, gap and silhouette.

Definition of int64_t

int64_t is guaranteed by the C99 standard to be exactly 64 bits wide on platforms that implement it, there's no such guarantee for a long which is at least 32 bits so it could be more.

§7.18.1.3 Exact-width integer types 1 The typedef name intN_t designates a signed integer type with width N , no padding bits, and a two’s complement representation. Thus, int8_t denotes a signed integer type with a width of exactly 8 bits.

how to open a url in python

with the webbrowser module

import webbrowser

webbrowser.open('http://example.com')  # Go to example.com

Inserting one list into another list in java?

Citing the official javadoc of List.addAll:

Appends all of the elements in the specified collection to the end of
this list, in the order that they are returned by the specified
collection's iterator (optional operation).  The behavior of this
operation is undefined if the specified collection is modified while
the operation is in progress.  (Note that this will occur if the
specified collection is this list, and it's nonempty.)

So you will copy the references of the objects in list to anotherList. Any method that does not operate on the referenced objects of anotherList (such as removal, addition, sorting) is local to it, and therefore will not influence list.

Android Percentage Layout Height

There is an attribute called android:weightSum.

You can set android:weightSum="2" in the parent linear_layout and android:weight="1" in the inner linear_layout.

Remember to set the inner linear_layout to fill_parent so weight attribute can work as expected.

Btw, I don't think its necesary to add a second view, altough I haven't tried. :)

<LinearLayout
    android:layout_height="fill_parent"
    android:layout_width="fill_parent"
    android:weightSum="2">

    <LinearLayout
        android:layout_height="fill_parent"
        android:layout_width="fill_parent"
        android:layout_weight="1">
    </LinearLayout>

</LinearLayout>

DSO missing from command line

DSO here means Dynamic Shared Object; since the error message says it's missing from the command line, I guess you have to add it to the command line.

That is, try adding -lpthread to your command line.

How to check if a python module exists without importing it

I came across this question while searching for a way to check if a module is loaded from the command line and would like to share my thoughts for the ones coming after me and looking for the same:

Linux/UNIX script file method: make a file module_help.py:

#!/usr/bin/env python

help('modules')

Then make sure it's executable: chmod u+x module_help.py

And call it with a pipe to grep:

./module_help.py | grep module_name

Invoke the built-in help system. (This function is intended for interactive use.) If no argument is given, the interactive help system starts on the interpreter console. If the argument is a string, then the string is looked up as the name of a module, function, class, method, keyword, or documentation topic, and a help page is printed on the console. If the argument is any other kind of object, a help page on the object is generated.

Interactive method: in the console load python

>>> help('module_name')

If found quit reading by typing q
To exit the python interactive session press Ctrl + D

Windows script file method also Linux/UNIX compatible, and better overall:

#!/usr/bin/env python

import sys

help(sys.argv[1])

Calling it from the command like:

python module_help.py site  

Would output:

Help on module site:

NAME site - Append module search paths for third-party packages to sys.path.

FILE /usr/lib/python2.7/site.py

MODULE DOCS http://docs.python.org/library/site

DESCRIPTION
...
:

and you'd have to press q to exit interactive mode.

Using it unknown module:

python module_help.py lkajshdflkahsodf

Would output:

no Python documentation found for 'lkajshdflkahsodf'

and exit.

How to decrypt Hash Password in Laravel

For compare hashed password with the plain text password string you can use the PHP password_verify

if(password_verify('1234567', $crypt_password_string)) {
    // in case if "$crypt_password_string" actually hides "1234567"
}

Eclipse internal error while initializing Java tooling

My issue was caused by some old Java projects using an old JRE System Library, so all I had to do was remove the old library and add the new one by right clicking the project -> Properties -> Java Build Path -> Libraries -> Add Library.

enter image description here

How to label scatterplot points by name?

For all those who don't have the option in Excel (like me), there is a macro which works and is explained here: https://www.get-digital-help.com/2015/08/03/custom-data-labels-in-x-y-scatter-chart/ Very useful

MacOSX homebrew mysql root password

  1. go to apple icon --> system preferences
  2. open Mysql
  3. in instances you will see "initialize Database"
  4. click on that
  5. you will be asked to set password for root --> set a strong password there
  6. use that password to login in mysql from next time

Hope this helps.

How to set a bitmap from resource

just replace this line

bm = BitmapFactory.decodeResource(null, R.id.image);

with

Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.YourImageName);

I mean to say just change null value with getResources() If you use this code in any button or Image view click event just append getApplicationContext() before getResources()..

Add a CSS border on hover without moving the element

add margin:-1px; which reduces 1px to each side. or if you need only for side you can do margin-left:-1px etc.

Sum columns with null values in oracle

The other answers regarding the use of nvl() are correct however none seem to address a more salient point:

Should you even have NULLs in this column?

Do they have a meaning other than 0?

This seems like a case where you should have a NOT NULL DEFAULT 0 on th ecolumn

C# Error "The type initializer for ... threw an exception

I tried your code:

CheckedListBox cb = new CheckedListBox();
for (var i = 1; i < 11; i++)
  cb.Items.Add("Item " + i, i % 3 == 0);

string fmt = RHelper.FormatQuery(cb);
Console.WriteLine(fmt);
Console.ReadLine();

It threw an exception at this line:

foreach (DataRowView item in chekedListBox.CheckedItems)

// Unable to cast object of type 'System.String' to type 'System.Data.DataRowView'.

Maybe you are also facing the same kind of problem. Instead of casting to DataRowView, try making the following changes:

foreach (var item in chekedListBox.CheckedItems)
{
    ID = ID + item.ToString(); // item["" + FieldName + ""];

Because items in CheckedListBox are of object type.

What is a PDB file?

Program Debug Database file (pdb) is a file format by Microsoft for storing debugging information.

When you build a project using Visual Studio or command prompt the compiler creates these symbol files.

Check Microsoft Docs

How to count lines of Java code using IntelliJ IDEA?

You can to use Count Lines of Code (CLOC)

On Settings -> External Tools add a new tool

  • Name: Count Lines of Code
  • Group: Statistics
  • Program: path/to/cloc
  • Parameters: $ProjectFileDir$ or $FileParentDir$

Flexbox Not Centering Vertically in IE

The original answer from https://github.com/philipwalton/flexbugs/issues/231#issuecomment-362790042

.flex-container{
min-height:100px;
display:flex;
align-items:center;
}

.flex-container:after{
content:'';
min-height:inherit;
font-size:0;
}

Send and Receive a file in socket programming in Linux with C/C++ (GCC/G++)

The most portable solution is just to read the file in chunks, and then write the data out to the socket, in a loop (and likewise, the other way around when receiving the file). You allocate a buffer, read into that buffer, and write from that buffer into your socket (you could also use send and recv, which are socket-specific ways of writing and reading data). The outline would look something like this:

while (1) {
    // Read data into buffer.  We may not have enough to fill up buffer, so we
    // store how many bytes were actually read in bytes_read.
    int bytes_read = read(input_file, buffer, sizeof(buffer));
    if (bytes_read == 0) // We're done reading from the file
        break;

    if (bytes_read < 0) {
        // handle errors
    }

    // You need a loop for the write, because not all of the data may be written
    // in one call; write will return how many bytes were written. p keeps
    // track of where in the buffer we are, while we decrement bytes_read
    // to keep track of how many bytes are left to write.
    void *p = buffer;
    while (bytes_read > 0) {
        int bytes_written = write(output_socket, p, bytes_read);
        if (bytes_written <= 0) {
            // handle errors
        }
        bytes_read -= bytes_written;
        p += bytes_written;
    }
}

Make sure to read the documentation for read and write carefully, especially when handling errors. Some of the error codes mean that you should just try again, for instance just looping again with a continue statement, while others mean something is broken and you need to stop.

For sending the file to a socket, there is a system call, sendfile that does just what you want. It tells the kernel to send a file from one file descriptor to another, and then the kernel can take care of the rest. There is a caveat that the source file descriptor must support mmap (as in, be an actual file, not a socket), and the destination must be a socket (so you can't use it to copy files, or send data directly from one socket to another); it is designed to support the usage you describe, of sending a file to a socket. It doesn't help with receiving the file, however; you would need to do the loop yourself for that. I cannot tell you why there is a sendfile call but no analogous recvfile.

Beware that sendfile is Linux specific; it is not portable to other systems. Other systems frequently have their own version of sendfile, but the exact interface may vary (FreeBSD, Mac OS X, Solaris).

In Linux 2.6.17, the splice system call was introduced, and as of 2.6.23 is used internally to implement sendfile. splice is a more general purpose API than sendfile. For a good description of splice and tee, see the rather good explanation from Linus himself. He points out how using splice is basically just like the loop above, using read and write, except that the buffer is in the kernel, so the data doesn't have to transferred between the kernel and user space, or may not even ever pass through the CPU (known as "zero-copy I/O").

How to add bootstrap to an angular-cli project

Just add these three lines in Head tag in index.html

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>

How do we use runOnUiThread in Android?

We use Worker Thread to make Apps smoother and avoid ANR's. We may need to update UI after the heavy process in worker Tread. The UI can only be updated from UI Thread. In such cases, we use Handler or runOnUiThread both have a Runnable run method that executes in UI Thread. The onClick method runs in UI thread so don't need to use runOnUiThread here.

Using Kotlin

While in Activity,

this.runOnUiThread {
      // Do stuff
}

From Fragment,

activity?.runOnUiThread {
      // Do stuff
}

Using Java,

this.runOnUiThread(new Runnable() {
     void run() {
         // Do stuff
     }
});

Print Html template in Angular 2 (ng-print in Angular 2)

That's how I've done it in angular2 (it is similar to that plunkered solution) In your HTML file:

<div id="print-section">
  // your html stuff that you want to print
</div>
<button (click)="print()">print</button>

and in your TS file :

print(): void {
    let printContents, popupWin;
    printContents = document.getElementById('print-section').innerHTML;
    popupWin = window.open('', '_blank', 'top=0,left=0,height=100%,width=auto');
    popupWin.document.open();
    popupWin.document.write(`
      <html>
        <head>
          <title>Print tab</title>
          <style>
          //........Customized style.......
          </style>
        </head>
    <body onload="window.print();window.close()">${printContents}</body>
      </html>`
    );
    popupWin.document.close();
}

UPDATE:

You can also shortcut the path and use merely ngx-print library for less inconsistent coding (mixing JS and TS) and more out-of-the-box controllable and secured printing cases.

Define make variable at rule execution time

In your example, the TMP variable is set (and the temporary directory created) whenever the rules for out.tar are evaluated. In order to create the directory only when out.tar is actually fired, you need to move the directory creation down into the steps:

out.tar : 
    $(eval TMP := $(shell mktemp -d))
    @echo hi $(TMP)/hi.txt
    tar -C $(TMP) cf $@ .
    rm -rf $(TMP)

The eval function evaluates a string as if it had been typed into the makefile manually. In this case, it sets the TMP variable to the result of the shell function call.

edit (in response to comments):

To create a unique variable, you could do the following:

out.tar : 
    $(eval $@_TMP := $(shell mktemp -d))
    @echo hi $($@_TMP)/hi.txt
    tar -C $($@_TMP) cf $@ .
    rm -rf $($@_TMP)

This would prepend the name of the target (out.tar, in this case) to the variable, producing a variable with the name out.tar_TMP. Hopefully, that is enough to prevent conflicts.

dotnet ef not found in .NET Core 3

I was having this problem after I installed the dotnet-ef tool using Ansible with sudo escalated previllage on Ubuntu. I had to add become: no for the Playbook task, then the dotnet-ef tool became available to the current user.

  - name: install dotnet tool dotnet-ef
    command: dotnet tool install --global dotnet-ef --version {{dotnetef_version}}
    become: no

What is the best way to convert seconds into (Hour:Minutes:Seconds:Milliseconds) time?

In VB.NET, but it's the same in C#:

Dim x As New TimeSpan(0, 0, 80)
debug.print(x.ToString())
' Will print 00:01:20

Cannot issue data manipulation statements with executeQuery()

To manipulate data you actually need executeUpdate() rather than executeQuery().

Here's an extract from the executeUpdate() javadoc which is already an answer at its own:

Executes the given SQL statement, which may be an INSERT, UPDATE, or DELETE statement or an SQL statement that returns nothing, such as an SQL DDL statement.

Freezing Row 1 and Column A at the same time

Select cell B2 and click "Freeze Panes" this will freeze Row 1 and Column A.

For future reference, selecting Freeze Panes in Excel will freeze the rows above your selected cell and the columns to the left of your selected cell. For example, to freeze rows 1 and 2 and column A, you could select cell B3 and click Freeze Panes. You could also freeze columns A and B and row 1, by selecting cell C2 and clicking "Freeze Panes".

Visual Aid on Freeze Panes in Excel 2010 - http://www.dummies.com/how-to/content/how-to-freeze-panes-in-an-excel-2010-worksheet.html

Microsoft Reference Guide (More Complicated, but resourceful none the less) - http://office.microsoft.com/en-us/excel-help/freeze-or-lock-rows-and-columns-HP010342542.aspx

How do I convert an NSString value to NSData?

NSString *str = @"helowrld";
// This converts the string to an NSData object
NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding];

you can take reference from this link

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

This takes care of nulls

var body = JObject.Parse("anyjsonString");

body?.SelectToken("path-string-prop")?.ToString();

body?.SelectToken("path-double-prop")?.ToObject<double>();

cocoapods - 'pod install' takes forever

As pointed out here git-remote-http process running in background. I goto this process from Activity Monitor and quitting this process resumed the pod process which was stuck on "Updating local specs repositories" after POD INSTALL

Sort a Custom Class List<T>

First things first, if the date property is storing a date, store it using a DateTime. If you parse the date through the sort you have to parse it for each item being compared, that's not very efficient...

You can then make an IComparer:

public class TagComparer : IComparer<cTag>
{
    public int Compare(cTag first, cTag second)
    {
        if (first != null && second != null)
        {
            // We can compare both properties.
            return first.date.CompareTo(second.date);
        }

        if (first == null && second == null)
        {
            // We can't compare any properties, so they are essentially equal.
            return 0;
        }

        if (first != null)
        {
            // Only the first instance is not null, so prefer that.
            return -1;
        }

        // Only the second instance is not null, so prefer that.
        return 1;
    }
}

var list = new List<cTag>();
// populate list.

list.Sort(new TagComparer());

You can even do it as a delegate:

list.Sort((first, second) =>
          {
              if (first != null && second != null)
                  return first.date.CompareTo(second.date);

              if (first == null && second == null)
                  return 0;

              if (first != null)
                  return -1;

              return 1;
          });

Using ping in c#

Imports System.Net.NetworkInformation


Public Function PingHost(ByVal nameOrAddress As String) As Boolean
    Dim pingable As Boolean = False
    Dim pinger As Ping
    Dim lPingReply As PingReply

    Try
        pinger = New Ping()
        lPingReply = pinger.Send(nameOrAddress)
        MessageBox.Show(lPingReply.Status)
        If lPingReply.Status = IPStatus.Success Then

            pingable = True
        Else
            pingable = False
        End If


    Catch PingException As Exception
        pingable = False
    End Try
    Return pingable
End Function

What's the difference between SHA and AES encryption?

SHA stands for Secure Hash Algorithm while AES stands for Advanced Encryption Standard. So SHA is a suite of hashing algorithms. AES on the other hand is a cipher which is used to encrypt. SHA algorithms (SHA-1, SHA-256 etc...) will take an input and produce a digest (hash), this is typically used in a digital signing process (produce a hash of some bytes and sign with a private key).

Using ORDER BY and GROUP BY together

You can try this

 SELECT tbl.* FROM (SELECT * FROM table ORDER BY timestamp DESC) as tbl
 GROUP BY tbl.m_id  

How do I add my new User Control to the Toolbox or a new Winform?

I found that user controls can exist in the same project.
As others have mentioned, AutoToolboxPopulate must be set to True.
Create the desired user control.
Select Build Solution.
If the new user control doesn't show up in the toolbox, close/open Visual Studio.
If the user controls still aren't showing up in the toolbox, right click on the toolbox and select Reset Toolbox. Then select Build Solution. If they still aren't there, restart Visual Studio.
There must not be any build errors when the solution is built, otherwise new toolbox items will not be added to the toolbox.

Get AVG ignoring Null or Zero values

NULL is already ignored so you can use NULLIF to turn 0 to NULL. Also you don't need DISTINCT and your WHERE on ActualTime is not sargable.

SELECT AVG(cast(NULLIF(a.SecurityW, 0) AS BIGINT)) AS Average1,
       AVG(cast(NULLIF(a.TransferW, 0) AS BIGINT)) AS Average2,
       AVG(cast(NULLIF(a.StaffW, 0) AS BIGINT))    AS Average3
FROM   Table1 a
WHERE  a.ActualTime >= '20130401'
       AND a.ActualTime < '20130501' 

PS I have no idea what Table2 b is in the original query for as there is no join condition for it so have omitted it from my answer.

How to delete multiple values from a vector?

UPDATE:

All of the above answers won't work for the repeated values, @BenBolker's answer using duplicated() predicate solves this:

full_vector[!full_vector %in% searched_vector | duplicated(full_vector)]

Original Answer: here I write a little function for this:

exclude_val<-function(full_vector,searched_vector){

      found=c()

      for(i in full_vector){  

        if(any(is.element(searched_vector,i))){
          searched_vector[(which(searched_vector==i))[1]]=NA
        }
        else{
          found=c(found,i)
        }
    }

    return(found)
}

so, let's say full_vector=c(1,2,3,4,1) and searched_vector=c(1,2,3).

exclude_val(full_vector,searched_vector) will return (4,1), however above answers will return just (4).

What is the return value of os.system() in Python?

Based on the answer of @AlokThakur (thanks!):

def run_system_command(command):
    return_value = os.system(command)
    # Calculate the return value code
    return_value = int(bin(return_value).replace("0b", "").rjust(16, '0')[:8], 2)
    if return_value != 0:
        raise RuntimeError(f'The system command\n{command}\nexited with return code {return_value}')

How to fetch the dropdown values from database and display in jsp

I made this in my code to do that

note: I am a beginner.

It is my jsp code.

<%
java.sql.Connection Conn = DBconnector.SetDBConnection(); /* make connector as you make in your code */
Statement st = null;
ResultSet rs = null;
st = Conn.createStatement();
rs = st.executeQuery("select * from department"); %>
<tr> 
    <td> 
        Student Major  : <select name ="Major">
        <%while(rs.next()){ %>
        <option value="<%=rs.getString(1)%>"><%=rs.getString(1)%></option>
                        <%}%>           
                         </select> 
   </td> 

How do I display the value of a Django form field in a template?

You can do this from the template with something like this:

{% if form.instance.some_field %}
      {{form.instance.some_field}}
{% else %}
      {{form.data.some_field}}
{% endif %}

This will display the instance value (if the form is created with an instance, you can use initial instead if you like), or else display the POST data such as when a validation error occurs.

What does ||= (or-equals) mean in Ruby?

b = 5
a ||= b

This translates to:

a = a || b

which will be

a = nil || 5

so finally

a = 5

Now if you call this again:

a ||= b
a = a || b
a = 5 || 5
a = 5

b = 6

Now if you call this again:

a ||= b
a = a || b
a = 5 || 6
a = 5 

If you observe, b value will not be assigned to a. a will still have 5.

Its a Memoization Pattern that is being used in Ruby to speed up accessors.

def users
  @users ||= User.all
end

This basically translates to:

@users = @users || User.all

So you will make a call to database for the first time you call this method.

Future calls to this method will just return the value of @users instance variable.

How to pass a null variable to a SQL Stored Procedure from C#.net code

    SQLParam = cmd.Parameters.Add("@RetailerID", SqlDbType.Int, 4)
    If p_RetailerID.Length = 0 Or p_RetailerID = "0" Then
        SQLParam.Value = DBNull.Value
    Else
        SQLParam.Value = p_RetailerID
    End If

How to add action listener that listens to multiple buttons

First, exend JFrame properly with a super() and a constructor then add actionlisteners to the frame and add the buttons.

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;


public class Calc extends JFrame implements ActionListener {
    JButton button1 = new JButton("1");
    JButton button2 = new JButton("2");

    public Calc()
    {
         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         setSize(100, 100);
         button1.addActionListener(this);
         button2.addActionListener(this);
         calcFrame.add(button1);
         calcFrame.add(button2);
    }
    public void actionPerformed(ActionEvent e)
    {
        Object source = e.getSource();
        if(source == button1)
        {
            \\button1 code here
        } else if(source == button2)
        {
            \\button2 code here
        }
    } 
    public static void main(String[] args)
    {

        JFrame calcFrame = new JFrame();
        calcFrame.setVisible(true);
    }
}

Windows Forms ProgressBar: Easiest way to start/stop marquee?

you can use a Timer (System.Windows.Forms.Timer).

Hook it's Tick event, advance then progress bar until it reaches the max value. when it does (hit the max) and you didn't finish the job, reset the progress bar value back to minimum.

...just like Windows Explorer :-)

How to add an element at the end of an array?

one-liner with streams

Stream.concat(Arrays.stream( array ), Stream.of( newElement )).toArray();

Effective method to hide email from spam bots

See Making email addresses safe from bots on a webpage?

I like the way Facebook and others render an image of your email address.

I have also used The Enkoder in the past - thought it was very good to be honest!

Autowiring fails: Not an managed Type

If anyone is strugling with the same problem I solved it by adding @EntityScan in my main class. Just add your model package to the basePackages property.

Unique Key constraints for multiple columns in Entity Framework

You need to define a composite key.

With data annotations it looks like this:

public class Entity
 {
   public string EntityId { get; set;}
   [Key]
   [Column(Order=0)]
   public int FirstColumn  { get; set;}
   [Key]
   [Column(Order=1)]
   public int SecondColumn  { get; set;}
 }

You can also do this with modelBuilder when overriding OnModelCreating by specifying:

modelBuilder.Entity<Entity>().HasKey(x => new { x.FirstColumn, x.SecondColumn });

Remove everything after a certain character

Worked for me:

      var first = regexLabelOut.replace(/,.*/g, "");

Access maven properties defined in the pom

You can parse the pom file with JDOM (http://www.jdom.org/).

Converting a date string to a DateTime object using Joda Time library

An simple method :

public static DateTime transfStringToDateTime(String dateParam, Session session) throws NotesException {
    DateTime dateRetour;
    dateRetour = session.createDateTime(dateParam);                 

    return dateRetour;
}

How do I pass a unique_ptr argument to a constructor or a function?

Yes you have to if you take the unique_ptr by value in the constructor. Explicity is a nice thing. Since unique_ptr is uncopyable (private copy ctor), what you wrote should give you a compiler error.

ThreadStart with parameters

As has already been mention in various answers here, the Thread class currently (4.7.2) provides several constructors and a Start method with overloads.

These relevant constructors for this question are:

public Thread(ThreadStart start);

and

public Thread(ParameterizedThreadStart start);

which either take a ThreadStart delegate or a ParameterizedThreadStart delegate.

The corresponding delegates look like this:

public delegate void ThreadStart();
public delegate void ParameterizedThreadStart(object obj);

So as can be seen, the correct constructor to use seems to be the one taking a ParameterizedThreadStart delegate so that some method conform to the specified signature of the delegate can be started by the thread.

A simple example for instanciating the Thread class would be

Thread thread = new Thread(new ParameterizedThreadStart(Work));

or just

Thread thread = new Thread(Work);

The signature of the corresponding method (called Work in this example) looks like this:

private void Work(object data)
{
   ...
}

What is left is to start the thread. This is done by using either

public void Start();

or

public void Start(object parameter);

While Start() would start the thread and pass null as data to the method, Start(...) can be used to pass anything into the Work method of the thread.

There is however one big problem with this approach: Everything passed into the Work method is cast into an object. That means within the Work method it has to be cast to the original type again like in the following example:

public static void Main(string[] args)
{
    Thread thread = new Thread(Work);

    thread.Start("I've got some text");
    Console.ReadLine();
}

private static void Work(object data)
{
    string message = (string)data; // Wow, this is ugly

    Console.WriteLine($"I, the thread write: {message}");
}



Casting is something you typically do not want to do.

What if someone passes something else which is not a string? As this seems not possible at first (because It is my method, I know what I do or The method is private, how should someone ever be able to pass anything to it?) you may possibly end up with exactly that case for various reasons. As some cases may not be a problem, others are. In such cases you will probably end up with an InvalidCastException which you probably will not notice because it simply terminates the thread.

As a solution you would expect to get a generic ParameterizedThreadStart delegate like ParameterizedThreadStart<T> where T would be the type of data you want to pass into the Work method. Unfortunately something like this does not exist (yet?).

There is however a suggested solution to this issue. It involves creating a class which contains both, the data to be passed to the thread as well as the method that represents the worker method like this:

public class ThreadWithState
{
    private string message;

    public ThreadWithState(string message)
    {
        this.message = message;
    }

    public void Work()
    {
        Console.WriteLine($"I, the thread write: {this.message}");
    }
}

With this approach you would start the thread like this:

ThreadWithState tws = new ThreadWithState("I've got some text");
Thread thread = new Thread(tws.Work);

thread.Start();

So in this way you simply avoid casting around and have a typesafe way of providing data to a thread ;-)

Closing Excel Application using VBA

Application.Quit 

Should do the trick.

How to pass a function as a parameter in Java?

Java 8 and above

Using Java 8+ lambda expressions, if you have a class or interface with only a single abstract method (sometimes called a SAM type), for example:

public interface MyInterface {
    String doSomething(int param1, String param2);
}

then anywhere where MyInterface is used, you can substitute a lambda expression:

class MyClass {
    public MyInterface myInterface = (p1, p2) -> { return p2 + p1; };
}

For example, you can create a new thread very quickly:

new Thread(() -> someMethod()).start();

And use the method reference syntax to make it even cleaner:

new Thread(this::someMethod).start();

Without lambda expressions, these last two examples would look like:

new Thread(new Runnable() { someMethod(); }).start();

Before Java 8

A common pattern would be to 'wrap' it within an interface, like Callable, for example, then you pass in a Callable:

public T myMethod(Callable<T> func) {
    return func.call();
}

This pattern is known as the Command Pattern.

Keep in mind you would be best off creating an interface for your particular usage. If you chose to go with callable, then you'd replace T above with whatever type of return value you expect, such as String.

In response to your comment below you could say:

public int methodToPass() { 
        // do something
}

public void dansMethod(int i, Callable<Integer> myFunc) {
       // do something
}

then call it, perhaps using an anonymous inner class:

dansMethod(100, new Callable<Integer>() {
   public Integer call() {
        return methodToPass();
   }
});

Keep in mind this is not a 'trick'. It's just java's basic conceptual equivalent to function pointers.

Only Add Unique Item To List

If your requirements are to have no duplicates, you should be using a HashSet.

HashSet.Add will return false when the item already exists (if that even matters to you).

You can use the constructor that @pstrjds links to below (or here) to define the equality operator or you'll need to implement the equality methods in RemoteDevice (GetHashCode & Equals).

How to Identify Microsoft Edge browser via CSS?

For Internet Explorer 

@media all and (-ms-high-contrast: none) {
        .banner-wrapper{
            background: rgba(0, 0, 0, 0.16)
         }
}

For Edge
@supports (-ms-ime-align:auto) {
    .banner-wrapper{
            background: rgba(0, 0, 0, 0.16);
         }
}

org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:transformClassesWithDexForDebug'

I have disabled Instant Run feature from the preferences and the issue was solved.

Send FormData with other field in AngularJS

This never gonna work, you can't stringify your FormData object.

You should do this:

this.uploadFileToUrl = function(file, title, text, uploadUrl){
   var fd = new FormData();
   fd.append('title', title);
   fd.append('text', text);
   fd.append('file', file);

     $http.post(uploadUrl, obj, {
       transformRequest: angular.identity,
       headers: {'Content-Type': undefined}
     })
  .success(function(){
    blockUI.stop();
  })
  .error(function(error){
    toaster.pop('error', 'Errore', error);
  });
}

Removing the title text of an iOS UIBarButtonItem

You can also use this:

UIBarButtonItem *temporaryBarButtonItem = [[UIBarButtonItem alloc] init];
temporaryBarButtonItem.title = @"";
self.navigationItem.backBarButtonItem = temporaryBarButtonItem;

[temporaryBarButtonItem release];

This works for me

Quoting backslashes in Python string literals

What Harley said, except the last point - it's not actually necessary to change the '/'s into '\'s before calling open. Windows is quite happy to accept paths with forward slashes.

infile = open('c:/folder/subfolder/file.txt')

The only time you're likely to need the string normpathed is if you're passing to to another program via the shell (using os.system or the subprocess module).

Openssl : error "self signed certificate in certificate chain"

Here is one-liner to verify certificate chain:

openssl verify -verbose -x509_strict -CAfile ca.pem cert_chain.pem

This doesn't require to install CA anywhere.

See How does an SSL certificate chain bundle work? for details.

javascript setTimeout() not working

If you want to pass a parameter to the delayed function:

    setTimeout(setTimer, 3000, param1, param2);

How can I do factory reset using adb in android?

You can send intent MASTER_CLEAR in adb:

adb shell am broadcast -a android.intent.action.MASTER_CLEAR

or as root

adb shell  "su -c 'am broadcast -a android.intent.action.MASTER_CLEAR'"

iCheck check if checkbox is checked

$('input').on('ifChanged', function(event) {
             if($(".checkbox").is(":checked")) {
                $value = $(this).val();
             }

             else if($(".checkbox").is(":not(:checked)")) {
                $value= $(this).val();
             }
        });

How to store decimal values in SQL Server?

DECIMAL(18,0) will allow 0 digits after the decimal point.

Use something like DECIMAL(18,4) instead that should do just fine!

That gives you a total of 18 digits, 4 of which after the decimal point (and 14 before the decimal point).

Difference between agile and iterative and incremental development

Some important and successfully executed software projects like Google Chrome and Mozilla Firefox are fine examples of both iterative and incremental software development.

I will quote fine ars technica article which describes this approach: http://arstechnica.com/information-technology/2010/07/chrome-team-sets-six-week-cadence-for-new-major-versions/

According to Chrome program manager Anthony Laforge, the increased pace is designed to address three main goals. One is to get new features out to users faster. The second is make the release schedule predictable and therefore easier to plan which features will be included and which features will be targeted for later releases. Third, and most counterintuitive, is to cut the level of stress for Chrome developers. Laforge explains that the shorter, predictable time periods between releases are more like "trains leaving Grand Central Station." New features that are ready don't have to wait for others that are taking longer to complete—they can just hop on the current release "train." This can in turn take the pressure off developers to rush to get other features done, since another release train will be coming in six weeks. And they can rest easy knowing their work isn't holding the train from leaving the station.<<

Python: Convert timedelta to int in a dataframe

Timedelta objects have read-only instance attributes .days, .seconds, and .microseconds.

Convert string into integer in bash script - "Leading Zero" number error

Since hours are always positive, and always 2 digits, you can set a 1 in front of it and subtract 100:

echo $((1$hour+1-100))

which is equivalent to

echo $((1$hour-99))

Be sure to comment such gymnastics. :)

Is there an equivalent to e.PageX position for 'touchstart' event as there is for click event?

Kinda late, but you need to access the original event, not the jQuery massaged one. Also, since these are multi-touch events, other changes need to be made:

$('#box').live('touchstart', function(e) {
  var xPos = e.originalEvent.touches[0].pageX;
});

If you want other fingers, you can find them in other indices of the touches list.

UPDATE FOR NEWER JQUERY:

$(document).on('touchstart', '#box', function(e) {
  var xPos = e.originalEvent.touches[0].pageX;
});

How do I do redo (i.e. "undo undo") in Vim?

CTRL+r

The "r" is lower-case.

How to check whether a pandas DataFrame is empty?

You can use the attribute df.empty to check whether it's empty or not:

if df.empty:
    print('DataFrame is empty!')

Source: Pandas Documentation

Error handling with try and catch in Laravel

You are inside a namespace so you should use \Exception to specify the global namespace:

try {

  $this->buildXMLHeader();

} catch (\Exception $e) {

    return $e->getMessage();
}

In your code you've used catch (Exception $e) so Exception is being searched in/as:

App\Services\PayUService\Exception

Since there is no Exception class inside App\Services\PayUService so it's not being triggered. Alternatively, you can use a use statement at the top of your class like use Exception; and then you can use catch (Exception $e).

Add new row to dataframe, at specific row-index, not appended?

The .before argument in dplyr::add_row can be used to specify the row.

dplyr::add_row(
  cars,
  speed = 0,
  dist = 0,
  .before = 3
)
#>    speed dist
#> 1      4    2
#> 2      4   10
#> 3      0    0
#> 4      7    4
#> 5      7   22
#> 6      8   16
#> ...

How to generate entire DDL of an Oracle schema (scriptable)?

The get_ddl procedure for a PACKAGE will return both spec AND body, so it will be better to change the query on the all_objects so the package bodies are not returned on the select.

So far I changed the query to this:

SELECT DBMS_METADATA.GET_DDL(REPLACE(object_type, ' ', '_'), object_name, owner)
FROM all_OBJECTS
WHERE (OWNER = 'OWNER1')
and object_type not like '%PARTITION'
and object_type not like '%BODY'
order by object_type, object_name;

Although other changes might be needed depending on the object types you are getting...

Save bitmap to location

Inside onActivityResult:

String filename = "pippo.png";
File sd = Environment.getExternalStorageDirectory();
File dest = new File(sd, filename);

Bitmap bitmap = (Bitmap)data.getExtras().get("data");
try {
     FileOutputStream out = new FileOutputStream(dest);
     bitmap.compress(Bitmap.CompressFormat.PNG, 90, out);
     out.flush();
     out.close();
} catch (Exception e) {
     e.printStackTrace();
}

Get original URL referer with PHP?

try this

(isset ($_SERVER['HTTP_CLIENT_IP']) ? 
    $_SERVER['HTTP_CLIENT_IP'] : 
    (isset ($_SERVER['HTTP_X_FORWARDED_FOR']) ? 
        $_SERVER['HTTP_X_FORWARDED_FOR'] : 
        $_SERVER['REMOTE_ADDR']
    )
)

How to make Regular expression into non-greedy?

The non-greedy regex modifiers are like their greedy counter-parts but with a ? immediately following them:

*  - zero or more
*? - zero or more (non-greedy)
+  - one or more
+? - one or more (non-greedy)
?  - zero or one
?? - zero or one (non-greedy)

What values can I pass to the event attribute of the f:ajax tag?

I just input some value that I knew was invalid and here is the output:

'whatToInput' is not a supported event for HtmlPanelGrid. Please specify one of these supported event names: click, dblclick, keydown, keypress, keyup, mousedown, mousemove, mouseout, mouseover, mouseup.

So values you can pass to event are

  • click
  • dblclick
  • keydown
  • mousedown
  • mousemove
  • mouseover
  • mouseup

Save current directory in variable using Bash?

I have the following in my .bash_profile:

function mark {
    export $1=`pwd`;
}

so anytime I want to remember a directory, I can just type, e.g. mark there .

Then when I want to go back to that location, I just type cd $there

Sending arrays with Intent.putExtra

This code sends array of integer values

Initialize array List

List<Integer> test = new ArrayList<Integer>();

Add values to array List

test.add(1);
test.add(2);
test.add(3);
Intent intent=new Intent(this, targetActivty.class);

Send the array list values to target activity

intent.putIntegerArrayListExtra("test", (ArrayList<Integer>) test);
startActivity(intent);

here you get values on targetActivty

Intent intent=getIntent();
ArrayList<String> test = intent.getStringArrayListExtra("test");

.htaccess mod_rewrite - how to exclude directory from rewrite rule

What you could also do is put a .htaccess file containing

RewriteEngine Off

In the folders you want to exclude from being rewritten (by the rules in a .htaccess file that's higher up in the tree). Simple but effective.

How to link an input button to a file select window?

You could use JavaScript and trigger the hidden file input when the button input has been clicked.

http://jsfiddle.net/gregorypratt/dhyzV/ - simple

http://jsfiddle.net/gregorypratt/dhyzV/1/ - fancier with a little JQuery

Or, you could style a div directly over the file input and set pointer-events in CSS to none to allow the click events to pass through to the file input that is "behind" the fancy div. This only works in certain browsers though; http://caniuse.com/pointer-events

addClass - can add multiple classes on same div?

$('.page-address-edit').addClass('test1 test2 test3');

Ref- jQuery

Prevent line-break of span element

white-space: nowrap is the correct solution but it will prevent any break in a line. If you only want to prevent line breaks between two elements it gets a bit more complicated:

<p>
    <span class="text">Some text</span>
    <span class="icon"></span>
</p>

To prevent breaks between the spans but to allow breaks between "Some" and "text" can be done by:

p {
    white-space: nowrap;
}

.text {
    white-space: normal;
}

That's good enough for Firefox. In Chrome you additionally need to replace the whitespace between the spans with an &nbsp;. (Removing the whitespace doesn't work.)

How do I create a branch?

Suppose you want to create a branch from a trunk name (as "TEST") then use:

svn cp -m "CREATE BRANCH TEST" $svn_url/trunk $svn_url/branches/TEST

C# using streams

Stream is just an abstraction (or a wrapper) over a physical stream of bytes. This physical stream is called the base stream. So there is always a base stream over which a stream wrapper is created and thus the wrapper is named after the base stream type ie FileStream, MemoryStream etc.

The advantage of the stream wrapper is that you get a unified api to interact with streams of any underlying type usb, file etc.

Why would you treat data as stream - because data chunks are loaded on-demand, we can inspect/process the data as chunks rather than loading the entire data into memory. This is how most of the programs deal with big files, for eg encrypting an OS image file.

Two Radio Buttons ASP.NET C#

Set the GroupName property of both radio buttons to the same value. You could also try using a RadioButtonGroup, which does this for you automatically.

How to use bootstrap datepicker

man you can use the basic Bootstrap Datepicker this way:

<!DOCTYPE html>
<head runat="server">
<title>Test Zone</title>
<link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css"/>
<link rel="stylesheet" type="text/css" href="Css/datepicker.css" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>
<script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
<script src="../Js/bootstrap-datepicker.js"></script>
<script type="text/javascript">
    $(document).ready(function () {
        $('#pickyDate').datepicker({
            format: "dd/mm/yyyy"
        });
    });
</script>

and inside body:

<body>
<div id="testDIV">
    <div class="container">
        <div class="hero-unit">
            <input  type="text" placeholder="click to show datepicker"  id="pickyDate"/>
        </div>
    </div>
</div>

datepicker.css and bootstrap-datepicker.js you can download from here on the Download button below "About" on the left side. Hope this help someone, greetings.

How do I manually create a file with a . (dot) prefix in Windows? For example, .htaccess

Go to command prompt, cd to the appropriate folder and type:

notepad .htaccess

After confirmation dialog the file will be created and you will be editing it directly. If you just want to create an empty file, try

echo. > .htaccess

How to pass List from Controller to View in MVC 3

  1. Create a model which contains your list and other things you need for the view.

    For example:

    public class MyModel
    {
        public List<string> _MyList { get; set; }
    }
    
  2. From the action method put your desired list to the Model, _MyList property, like:

    public ActionResult ArticleList(MyModel model)
    {
        model._MyList = new List<string>{"item1","item2","item3"};
        return PartialView(@"~/Views/Home/MyView.cshtml", model);
    }
    
  3. In your view access the model as follows

    @model MyModel
    foreach (var item in Model)
    {
       <div>@item</div>
    }
    

I think it will help for start.

What is the Python equivalent for a case/switch statement?

While the official docs are happy not to provide switch, I have seen a solution using dictionaries.

For example:

# define the function blocks
def zero():
    print "You typed zero.\n"

def sqr():
    print "n is a perfect square\n"

def even():
    print "n is an even number\n"

def prime():
    print "n is a prime number\n"

# map the inputs to the function blocks
options = {0 : zero,
           1 : sqr,
           4 : sqr,
           9 : sqr,
           2 : even,
           3 : prime,
           5 : prime,
           7 : prime,
}

Then the equivalent switch block is invoked:

options[num]()

This begins to fall apart if you heavily depend on fall through.

ASP.NET MVC get textbox input value

Another way by using ajax method:

View:

@Html.TextBox("txtValue", null, new { placeholder = "Input value" })
<input type="button" value="Start" id="btnStart"  />

<script>
    $(function () {
        $('#btnStart').unbind('click');
        $('#btnStart').on('click', function () {
            $.ajax({
                url: "/yourControllerName/yourMethod",
                type: 'POST',
                contentType: "application/json; charset=utf-8",
                dataType: 'json',
                data: JSON.stringify({
                    txtValue: $("#txtValue").val()
                }),
                async: false
            });
       });
   });
</script>

Controller:

[HttpPost]
public EmptyResult YourMethod(string txtValue)
{
    // do what you want with txtValue
    ...
}

Set up a scheduled job?

I had exactly the same requirement a while ago, and ended up solving it using APScheduler (User Guide)

It makes scheduling jobs super simple, and keeps it independent for from request-based execution of some code. Following is a simple example.

from apscheduler.schedulers.background import BackgroundScheduler

scheduler = BackgroundScheduler()
job = None

def tick():
    print('One tick!')\

def start_job():
    global job
    job = scheduler.add_job(tick, 'interval', seconds=3600)
    try:
        scheduler.start()
    except:
        pass

Hope this helps somebody!

What data type to use for hashed password field and what length?

for md5 vARCHAR(32) is appropriate. For those using AES better to use varbinary.

Android: How to handle right to left swipe gestures

I know its a bit late since 2012 but I hope it will help someone since I think it's a shorter and cleaner code than most of the answers:

view.setOnTouchListener((v, event) -> {
        
int action = MotionEventCompat.getActionMasked(event);

switch(action) {
    case (MotionEvent.ACTION_DOWN) :
        Log.d(DEBUG_TAG,"Action was DOWN");
        return true;

    case (MotionEvent.ACTION_MOVE) :
        Log.d(DEBUG_TAG,"Action was MOVE");
        return true;

    case (MotionEvent.ACTION_UP) :
        Log.d(DEBUG_TAG,"Action was UP");
        return true;

    case (MotionEvent.ACTION_CANCEL) :
        Log.d(DEBUG_TAG,"Action was CANCEL");
        return true;

    case (MotionEvent.ACTION_OUTSIDE) :
        Log.d(DEBUG_TAG,"Movement occurred outside bounds " +
                "of current screen element");
        return true;

    default :
        return super.onTouchEvent(event);
}
    });

of course you can leave only the relevant gestures to you.

src: https://developer.android.com/training/gestures/detector

How do I create a circle or square with just CSS - with a hollow center?

You can use special characters to make lots of shapes. Examples: http://jsfiddle.net/martlark/jWh2N/2/

_x000D_
_x000D_
<table>_x000D_
  <tr>_x000D_
    <td>hollow square</td>_x000D_
    <td>&#9633;</td>_x000D_
  </tr>_x000D_
  <tr>_x000D_
    <td>solid circle</td>_x000D_
    <td>&bull;</td>_x000D_
  </tr>_x000D_
  <tr>_x000D_
    <td>open circle</td>_x000D_
    <td>&#3664;</td>_x000D_
  </tr>_x000D_
_x000D_
</table>
_x000D_
_x000D_
_x000D_

enter image description here

Many more can be found here: HTML Special Characters

Include CSS and Javascript in my django template

First, create staticfiles folder. Inside that folder create css, js, and img folder.

settings.py

import os

PROJECT_DIR = os.path.dirname(__file__)

DATABASES = {
    'default': {
         'ENGINE': 'django.db.backends.sqlite3', 
         'NAME': os.path.join(PROJECT_DIR, 'myweblabdev.sqlite'),                        
         'USER': '',
         'PASSWORD': '',
         'HOST': '',                      
         'PORT': '',                     
    }
}

MEDIA_ROOT = os.path.join(PROJECT_DIR, 'media')

MEDIA_URL = '/media/'

STATIC_ROOT = os.path.join(PROJECT_DIR, 'static')

STATIC_URL = '/static/'

STATICFILES_DIRS = (
    os.path.join(PROJECT_DIR, 'staticfiles'),
)

main urls.py

from django.conf.urls import patterns, include, url
from django.conf.urls.static import static
from django.contrib import admin
from django.contrib.staticfiles.urls import staticfiles_urlpatterns
from myweblab import settings

admin.autodiscover()

urlpatterns = patterns('',
    .......
) + static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)

urlpatterns += staticfiles_urlpatterns()

template

{% load static %}

<link rel="stylesheet" href="{% static 'css/style.css' %}">

Incrementing a variable inside a Bash loop

while read -r country _; do
  if [[ $country = 'US' ]]; then
    ((USCOUNTER++))
    echo "US counter $USCOUNTER"
  fi
done < "$FILE"

What's the fastest way of checking if a point is inside a polygon in python

You can consider shapely:

from shapely.geometry import Point
from shapely.geometry.polygon import Polygon

point = Point(0.5, 0.5)
polygon = Polygon([(0, 0), (0, 1), (1, 1), (1, 0)])
print(polygon.contains(point))

From the methods you've mentioned I've only used the second, path.contains_points, and it works fine. In any case depending on the precision you need for your test I would suggest creating a numpy bool grid with all nodes inside the polygon to be True (False if not). If you are going to make a test for a lot of points this might be faster (although notice this relies you are making a test within a "pixel" tolerance):

from matplotlib import path
import matplotlib.pyplot as plt
import numpy as np

first = -3
size  = (3-first)/100
xv,yv = np.meshgrid(np.linspace(-3,3,100),np.linspace(-3,3,100))
p = path.Path([(0,0), (0, 1), (1, 1), (1, 0)])  # square with legs length 1 and bottom left corner at the origin
flags = p.contains_points(np.hstack((xv.flatten()[:,np.newaxis],yv.flatten()[:,np.newaxis])))
grid = np.zeros((101,101),dtype='bool')
grid[((xv.flatten()-first)/size).astype('int'),((yv.flatten()-first)/size).astype('int')] = flags

xi,yi = np.random.randint(-300,300,100)/100,np.random.randint(-300,300,100)/100
vflag = grid[((xi-first)/size).astype('int'),((yi-first)/size).astype('int')]
plt.imshow(grid.T,origin='lower',interpolation='nearest',cmap='binary')
plt.scatter(((xi-first)/size).astype('int'),((yi-first)/size).astype('int'),c=vflag,cmap='Greens',s=90)
plt.show()

, the results is this:

point inside polygon within pixel tolerance

Oracle SQL, concatenate multiple columns + add text

Try this:

SELECT 'I like ' || type_column_name || ' cake with ' || 
icing_column_name || ' and a ' fruit_column_name || '.' 
AS Cake_Column FROM your_table_name;

It should concatenate all that data as a single column entry named "Cake_Column".

Return JSON for ResponseEntity<String>

public ResponseEntity<?> ApiCall(@PathVariable(name = "id") long id) {
    JSONObject resp = new JSONObject();
    resp.put("status", 0);
    resp.put("id", id);

    return new ResponseEntity<String>(resp.toString(), HttpStatus.CREATED);
}

insert data from one table to another in mysql

INSERT INTO mt_magazine_subscription SELECT *
       FROM tbl_magazine_subscription 
       ORDER BY magazine_subscription_id ASC

how to set ulimit / file descriptor on docker container the image tag is phusion/baseimage-docker

I have tried many options and unsure as to why a few solutions suggested above work on one machine and not on others.

A solution that works and that is simple and can work per container is:

docker run --ulimit memlock=819200000:819200000 -h <docker_host_name> --name=current -v /home/user_home:/user_home -i -d -t docker_user_name/image_name

SQL Server® 2016, 2017 and 2019 Express full download

When you can't apply Juki's answer then after selecting the desired version of media you can use Fiddler to determine where the files are located.

SQL Server 2019 Express Edition (English):

SQL Server 2017 Express Edition (English):

SQL Server 2016 with SP2 Express Edition (English):

SQL Server 2016 with SP1 Express Edition (English):

And here is how to use Fiddler.

How to convert integers to characters in C?

In C, int, char, long, etc. are all integers.

They typically have different memory sizes and thus different ranges as in INT_MIN to INT_MAX. char and arrays of char are often used to store characters and strings. Integers are stored in many types: int being the most popular for a balance of speed, size and range.

ASCII is by far the most popular character encoding, but others exist. The ASCII code for an 'A' is 65, 'a' is 97, '\n' is 10, etc. ASCII data is most often stored in a char variable. If the C environment is using ASCII encoding, the following all store the same value into the integer variable.

int i1 = 'a';
int i2 = 97;
char c1 = 'a';
char c2 = 97;

To convert an int to a char, simple assign:

int i3 = 'b';
int i4 = i3;
char c3;
char c4;
c3 = i3;
// To avoid a potential compiler warning, use a cast `char`.
c4 = (char) i4; 

This warning comes up because int typically has a greater range than char and so some loss-of-information may occur. By using the cast (char), the potential loss of info is explicitly directed.

To print the value of an integer:

printf("<%c>\n", c3); // prints <b>

// Printing a `char` as an integer is less common but do-able
printf("<%d>\n", c3); // prints <98>

// Printing an `int` as a character is less common but do-able.
// The value is converted to an `unsigned char` and then printed.
printf("<%c>\n", i3); // prints <b>

printf("<%d>\n", i3); // prints <98>

There are additional issues about printing such as using %hhu or casting when printing an unsigned char, but leave that for later. There is a lot to printf().

One line if/else condition in linux shell scripting

It's not a direct answer to the question but you could just use the OR-operator

( grep "#SystemMaxUse=" journald.conf > /dev/null && sed -i 's/\#SystemMaxUse=/SystemMaxUse=50M/g' journald.conf ) || echo "This file has been edited. You'll need to do it manually."

Iterating over all the keys of a map

Here's some easy way to get slice of the map-keys.

// Return keys of the given map
func Keys(m map[string]interface{}) (keys []string) {
    for k := range m {
        keys = append(keys, k)
    }
    return keys
}

// use `Keys` func
func main() {
    m := map[string]interface{}{
        "foo": 1,
        "bar": true,
        "baz": "baz",
    }
    fmt.Println(Keys(m)) // [foo bar baz]
}

Heroku: How to push different local Git branches to Heroku/master

Heroku labs now offers a github add-on that let's you specify which branch to push.

See Heroku's write up on this beta feature.

You'll need to sign-up as a beta tester for the time-being.

How to choose the id generation strategy when using JPA and Hibernate


A while ago i wrote a detailed article about Hibernate key generators: http://blog.eyallupu.com/2011/01/hibernatejpa-identity-generators.html

Choosing the correct generator is a complicated task but it is important to try and get it right as soon as possible - a late migration might be a nightmare.

A little off topic but a good chance to raise a point usually overlooked which is sharing keys between applications (via API). Personally I always prefer surrogate keys and if I need to communicate my objects with other systems I don't expose my key (even though it is a surrogate one) – I use an additional ‘external key’. As a consultant I have seen more than once 'great' system integrations using object keys (the 'it is there let's just use it' approach) just to find a year or two later that one side has issues with the key range or something of the kind requiring a deep migration on the system exposing its internal keys. Exposing your key means exposing a fundamental aspect of your code to external constrains shouldn’t really be exposed to.

Running .sh scripts in Git Bash

If by any chance you've changed the default open for .sh files to a text editor like I had, you can just "bash .\yourscript.sh", provided you have git bash installed and in path.

Using FFmpeg in .net?

a few other managed wrappers for you to check out

Writing your own interop wrappers can be a time-consuming and difficult process in .NET. There are some advantages to writing a C++ library for the interop - particularly as it allows you to greatly simplify the interface that the C# code. However, if you are only needing a subset of the library, it might make your life easier to just do the interop in C#.

Get raw POST body in Python Flask regardless of Content-Type header

Use request.get_data() to get the raw data, regardless of content type. The data is cached and you can subsequently access request.data, request.json, request.form at will.

If you access request.data first, it will call get_data with an argument to parse form data first. If the request has a form content type (multipart/form-data, application/x-www-form-urlencoded, or application/x-url-encoded) then the raw data will be consumed. request.data and request.json will appear empty in this case.

Resetting a form in Angular 2 after submit

if anybody wants to clear out only a particular form control one can use

formSubmit(){
this.formName.patchValue({
         formControlName:''
          //or if one wants to change formControl to a different value on submit
          formControlName:'form value after submission'     
    });
}

How do you implement a re-try-catch?

simple

int MAX = 3;

int count = 0;
while (true) {
    try {
        ...

        break;
    } catch (Exception e) {
        if (count++ < MAX) {
            continue;
        }

        ...
        
        break;
    }
}

Log4j2 configuration - No log4j2 configuration file found

Eclipse will never see a file until you force a refresh of the IDE. Its a feature! So you can put the file all over the project and Eclipse will ignore it completely and throw these errors. Hit refresh in Eclipse project view and then it works.

iOS 10: "[App] if we're in the real pre-commit handler we can't actually add any new fences due to CA restriction"

To fix, I deleted the app from Simulator.

I also ran Clean first.

I do not think anything orientation-related triggered it. The biggest thing that changed before this symptom started is that a Swift framework started calling NSLog on worker threads instead of main thread.

Find specific string in a text file with VBS script

Wow, after few attempts I finally figured out how to deal with my text edits in vbs. The code works perfectly, it gives me the result I was expecting. Maybe it's not the best way to do this, but it does its job. Here's the code:

Option Explicit

Dim StdIn:  Set StdIn = WScript.StdIn
Dim StdOut: Set StdOut = WScript


Main()

Sub Main()

Dim objFSO, filepath, objInputFile, tmpStr, ForWriting, ForReading, count, text, objOutputFile, index, TSGlobalPath, foundFirstMatch
Set objFSO = CreateObject("Scripting.FileSystemObject")
TSGlobalPath = "C:\VBS\TestSuiteGlobal\Test suite Dispatch Decimal - Global.txt"
ForReading = 1
ForWriting = 2
Set objInputFile = objFSO.OpenTextFile(TSGlobalPath, ForReading, False)
count = 7
text=""
foundFirstMatch = false

Do until objInputFile.AtEndOfStream
    tmpStr = objInputFile.ReadLine
    If foundStrMatch(tmpStr)=true Then
        If foundFirstMatch = false Then
            index = getIndex(tmpStr)
            foundFirstMatch = true
            text = text & vbCrLf & textSubstitution(tmpStr,index,"true")
        End If
        If index = getIndex(tmpStr) Then
            text = text & vbCrLf & textSubstitution(tmpStr,index,"false")
        ElseIf index < getIndex(tmpStr) Then
            index = getIndex(tmpStr)
            text = text & vbCrLf & textSubstitution(tmpStr,index,"true")
        End If
    Else
        text = text & vbCrLf & textSubstitution(tmpStr,index,"false")
    End If
Loop
Set objOutputFile = objFSO.CreateTextFile("C:\VBS\NuovaProva.txt", ForWriting, true)
objOutputFile.Write(text)
End Sub


Function textSubstitution(tmpStr,index,foundMatch)
Dim strToAdd
strToAdd = "<tr><td><a href=" & chr(34) & "../../Logs/CF5.0_Features/Beginning_of_CF5.0_Features_TC" & CStr(index) & ".html" & chr(34) & ">Beginning_of_CF5.0_Features_TC" & CStr(index) & "</a></td></tr>"
If foundMatch = "false" Then
    textSubstitution = tmpStr
ElseIf foundMatch = "true" Then
    textSubstitution = strToAdd & vbCrLf & tmpStr
End If
End Function


Function getIndex(tmpStr)
Dim substrToFind, charAtPos, char1, char2
substrToFind = "<tr><td><a href=" & chr(34) & "../Test case "
charAtPos = len(substrToFind) + 1
char1 = Mid(tmpStr, charAtPos, 1)
char2 = Mid(tmpStr, charAtPos+1, 1)
If IsNumeric(char2) Then
    getIndex = CInt(char1 & char2)
Else
    getIndex = CInt(char1)
End If
End Function

Function foundStrMatch(tmpStr)
Dim substrToFind
substrToFind = "<tr><td><a href=" & chr(34) & "../Test case "
If InStr(tmpStr, substrToFind) > 0 Then
    foundStrMatch = true
Else
    foundStrMatch = false
End If
End Function

This is the original txt file

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
  <meta content="text/html; charset=UTF-8" http-equiv="content-type" />
  <title>Test Suite</title>
</head>
<body>
<table id="suiteTable" cellpadding="1" cellspacing="1" border="1" class="selenium"><tbody>
<tr><td><b>Test Suite</b></td></tr>
<tr><td><a href="../../Component/TC_Environment_setting">TC_Environment_setting</a></td></tr>
<tr><td><a href="../../Component/TC_Set_variables">TC_Set_variables</a></td></tr>
<tr><td><a href="../../Component/TC_Set_ID">TC_Set_ID</a></td></tr>
<tr><td><a href="../../Login/Log_in_Admin">Log_in_Admin</a></td></tr>
<tr><td><a href="../../Component/Set_Roles_Dispatch_Decimal">Set_Roles_Dispatch_Decimal</a></td></tr>
<tr><td><a href="../../Login/Log_ in_U1A1">Log_ in_U1A1</a></td></tr>
<tr><td><a href="../Test case 5 DD/Form1">Form1</a></td></tr>
<tr><td><a href="../Test case 5 DD/contrD1">contrD1</a></td></tr>
<tr><td><a href="../../Login/Logout">Logout</a></td></tr>
<tr><td><a href="../../Login/Log_ in_U1B1">Log_ in_U1B1</a></td></tr>
<tr><td><a href="../../Component/Search&OpenApp">Search&OpenApp</a></td></tr>
<tr><td><a href="../Test case 5 DD/FormEND">FormEND</a></td></tr>
<tr><td><a href="../../Component/Controllo END">Controllo END</a></td></tr>
<tr><td><a href="../../Login/Logout">Logout</a></td></tr>
<tr><td><a href="../../Login/Log_ in_U1A1">Log_ in_U1A1</a></td></tr>
<tr><td><a href="../Test case 6 DD/Form1">Form1</a></td></tr>
<tr><td><a href="../Test case 6 DD/contrD1">contrD1</a></td></tr>
<tr><td><a href="../../Login/Logout">Logout</a></td></tr>
<tr><td><a href="../../Login/Log_ in_U1B1">Log_ in_U1B1</a></td></tr>
<tr><td><a href="../../Component/Search&OpenApp">Search&OpenApp</a></td></tr>
<tr><td><a href="../Test case 5 DD/FormEND">FormEND</a></td></tr>
<tr><td><a href="../../Component/Controllo END">Controllo END</a></td></tr>
<tr><td><a href="../../Login/Logout">Logout</a></td></tr>
<tr><td><a href="../../Login/Log_ in_U1A1">Log_ in_U1A1</a></td></tr>
<tr><td><a href="../Test case 7 DD/Form1">Form1</a></td></tr>
<tr><td><a href="../../Component/Controllo DeadLetter">Controllo DeadLetter</a></td></tr>
<tr><td><a href="../../Login/Logout">Logout</a></td></tr>
<tr><td><a href="../../Component/Set_Roles_Dispatch_Decimal">Set_Roles_Dispatch_Decimal</a></td></tr>
<tr><td><a href="../../Login/Logout_BAC">Logout_BAC</a></td></tr>
</tbody></table>
</body>
</html>

And this is the result I'm expecting

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
  <meta content="text/html; charset=UTF-8" http-equiv="content-type" />
  <title>Test Suite</title>
</head>
<body>
<table id="suiteTable" cellpadding="1" cellspacing="1" border="1" class="selenium"><tbody>
<tr><td><b>Test Suite</b></td></tr>
<tr><td><a href="../../Component/TC_Environment_setting">TC_Environment_setting</a></td></tr>
<tr><td><a href="../../Component/TC_Set_variables">TC_Set_variables</a></td></tr>
<tr><td><a href="../../Component/TC_Set_ID">TC_Set_ID</a></td></tr>
<tr><td><a href="../../Login/Log_in_Admin">Log_in_Admin</a></td></tr>
<tr><td><a href="../../Component/Set_Roles_Dispatch_Decimal">Set_Roles_Dispatch_Decimal</a></td></tr>
<tr><td><a href="../../Login/Log_ in_U1A1">Log_ in_U1A1</a></td></tr>
<tr><td><a href="../../Logs/CF5.0_Features/Beginning_of_CF5.0_Features_TC5.html">Beginning_of_CF5.0_Features_TC5</a></td></tr>
<tr><td><a href="../Test case 5 DD/Form1">Form1</a></td></tr>
<tr><td><a href="../Test case 5 DD/Form1">Form1</a></td></tr>
<tr><td><a href="../Test case 5 DD/contrD1">contrD1</a></td></tr>
<tr><td><a href="../../Login/Logout">Logout</a></td></tr>
<tr><td><a href="../../Login/Log_ in_U1B1">Log_ in_U1B1</a></td></tr>
<tr><td><a href="../../Component/Search&OpenApp">Search&OpenApp</a></td></tr>
<tr><td><a href="../Test case 5 DD/FormEND">FormEND</a></td></tr>
<tr><td><a href="../../Component/Controllo END">Controllo END</a></td></tr>
<tr><td><a href="../../Login/Logout">Logout</a></td></tr>
<tr><td><a href="../../Login/Log_ in_U1A1">Log_ in_U1A1</a></td></tr>
<tr><td><a href="../../Logs/CF5.0_Features/Beginning_of_CF5.0_Features_TC6.html">Beginning_of_CF5.0_Features_TC6</a></td></tr>
<tr><td><a href="../Test case 6 DD/Form1">Form1</a></td></tr>
<tr><td><a href="../Test case 6 DD/contrD1">contrD1</a></td></tr>
<tr><td><a href="../../Login/Logout">Logout</a></td></tr>
<tr><td><a href="../../Login/Log_ in_U1B1">Log_ in_U1B1</a></td></tr>
<tr><td><a href="../../Component/Search&OpenApp">Search&OpenApp</a></td></tr>
<tr><td><a href="../../Component/Controllo END">Controllo END</a></td></tr>
<tr><td><a href="../../Login/Logout">Logout</a></td></tr>
<tr><td><a href="../../Login/Log_ in_U1A1">Log_ in_U1A1</a></td></tr>
<tr><td><a href="../../Logs/CF5.0_Features/Beginning_of_CF5.0_Features_TC7.html">Beginning_of_CF5.0_Features_TC7</a></td></tr>
<tr><td><a href="../Test case 7 DD/Form1">Form1</a></td></tr>
<tr><td><a href="../../Component/Controllo DeadLetter">Controllo DeadLetter</a></td></tr>
<tr><td><a href="../../Login/Logout">Logout</a></td></tr>
<tr><td><a href="../../Component/Set_Roles_Dispatch_Decimal">Set_Roles_Dispatch_Decimal</a></td></tr>
<tr><td><a href="../../Login/Logout_BAC">Logout_BAC</a></td></tr>
</tbody></table>
</body>
</html>

Where to put default parameter value in C++?

Although this is an "old" thread, I still would like to add the following to it:

I've experienced the next case:

  • In the header file of a class, I had
int SetI2cSlaveAddress( UCHAR addr, bool force );
  • In the source file of that class, I had
int CI2cHal::SetI2cSlaveAddress( UCHAR addr, bool force = false )
{
   ...
}

As one can see, I had put the default value of the parameter "force" in the class source file, not in the class header file.

Then I used that function in a derived class as follows (derived class inherited the base class in a public way):

SetI2cSlaveAddress( addr );

assuming it would take the "force" parameter as "false" 'for granted'.

However, the compiler (put in c++11 mode) complained and gave me the following compiler error:

/home/.../mystuff/domoproject/lib/i2cdevs/max6956io.cpp: In member function 'void CMax6956Io::Init(unsigned char, unsigned char, unsigned int)':
/home/.../mystuff/domoproject/lib/i2cdevs/max6956io.cpp:26:30: error: no matching function for call to 'CMax6956Io::SetI2cSlaveAddress(unsigned char&)'
/home/.../mystuff/domoproject/lib/i2cdevs/max6956io.cpp:26:30: note: candidate is:
In file included from /home/geertvc/mystuff/domoproject/lib/i2cdevs/../../include/i2cdevs/max6956io.h:35:0,
                 from /home/geertvc/mystuff/domoproject/lib/i2cdevs/max6956io.cpp:1:
/home/.../mystuff/domoproject/lib/i2cdevs/../../include/i2chal/i2chal.h:65:9: note: int CI2cHal::SetI2cSlaveAddress(unsigned char, bool)
/home/.../mystuff/domoproject/lib/i2cdevs/../../include/i2chal/i2chal.h:65:9: note:   candidate expects 2 arguments, 1 provided
make[2]: *** [lib/i2cdevs/CMakeFiles/i2cdevs.dir/max6956io.cpp.o] Error 1
make[1]: *** [lib/i2cdevs/CMakeFiles/i2cdevs.dir/all] Error 2
make: *** [all] Error 2

But when I added the default parameter in the header file of the base class:

int SetI2cSlaveAddress( UCHAR addr, bool force = false );

and removed it from the source file of the base class:

int CI2cHal::SetI2cSlaveAddress( UCHAR addr, bool force )

then the compiler was happy and all code worked as expected (I could give one or two parameters to the function SetI2cSlaveAddress())!

So, not only for the user of a class it's important to put the default value of a parameter in the header file, also compiling and functional wise it apparently seems to be a must!

Can you force a React component to rerender without calling setState?

There are a few ways to rerender your component:

The simplest solution is to use forceUpdate() method:

this.forceUpdate()

One more solution is to create not used key in the state(nonUsedKey) and call setState function with update of this nonUsedKey:

this.setState({ nonUsedKey: Date.now() } );

Or rewrite all current state:

this.setState(this.state);

Props changing also provides component rerender.

Difference between int and double

Short answer:

int uses up 4 bytes of memory (and it CANNOT contain a decimal), double uses 8 bytes of memory. Just different tools for different purposes.

rails 3 validation on uniqueness on multiple attributes

Multiple Scope Parameters:

class TeacherSchedule < ActiveRecord::Base
  validates_uniqueness_of :teacher_id, :scope => [:semester_id, :class_id]
end

http://apidock.com/rails/ActiveRecord/Validations/ClassMethods/validates_uniqueness_of

This should answer Greg's question.

How to pre-populate the sms body text via an html link

(Just a little bit of topic), but maybe if you searched you could stumble here... In markdown (tested with parsedown and on iOS / android) you could do :

   [Link](sms:phone_number,?&body=URL_encoded_body_text)
   //[send sms](sms:1234567890;?&body=my%20very%20interesting%20text)

Fixing npm path in Windows 8 and 10

When you're on Windows but running VS Code in Windows Subsystem for Linux like this

linux@user: /home$ code .

you actually want to install NodeJs on Linux with

linux@user: /home$ sudo apt install nodejs

Installing NodeJs on Windows, modifying PATH and restarting will get you no results.

How do I install cygwin components from the command line?

Old question, but still relevant. Here is what worked for me today (6/26/16).

From the bash shell:

lynx -source rawgit.com/transcode-open/apt-cyg/master/apt-cyg > apt-cyg
install apt-cyg /bin

Currency formatting in Python

If you are using OSX and have yet to set your locale module setting this first answer will not work you will receive the following error:

Traceback (most recent call last):File "<stdin>", line 1, in <module> File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/locale.py", line 221, in currency
raise ValueError("Currency formatting is not possible using "ValueError: Currency formatting is not possible using the 'C' locale.

To remedy this you will have to do use the following:

locale.setlocale(locale.LC_ALL, 'en_US')

StringIO in Python3

I hope this will meet your requirement

import PyPDF4
import io

pdfFile = open(r'test.pdf', 'rb')
pdfReader = PyPDF4.PdfFileReader(pdfFile)
pageObj = pdfReader.getPage(1)
pagetext = pageObj.extractText()

for line in io.StringIO(pagetext):
    print(line)

How to change the font and font size of an HTML input tag?

In your 'head' section, add this code:

<style>
input[type='text'] { font-size: 24px; }
</style>

Or you can only add the:

input[type='text'] { font-size: 24px; }

to a CSS file which can later be included.

You can also change the font face by using the CSS property: font-family

font-family: monospace;

So you can have a CSS code like this:

input[type='text'] { font-size: 24px; font-family: monospace; }

You can find further help at the W3Schools website.

I suggest you to have a look at the CSS3 specification. With CSS3 you can also load a font from the web instead of having the limitation to use only the most common fonts or tell the user to download the font you're using.

Vim for Windows - What do I type to save and exit from a file?

Instead of telling you how you could execute a certain command (Esc:wq), I can provide you two links that may help you with VIM:

However, the best way to learn Vim is not only using it for Git commits, but as a regular editor for your everyday work.

If you're not going to switch to Vim, it's nonsense to keep its commands in mind. In that case, go and set up your favourite editor to use with Git.

How to render a PDF file in Android

I used the below code to open and print the PDF using Wi-Fi. I am sending my whole code, and I hope it is helpful.

public class MainActivity extends Activity {

    int Result_code = 1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button mButton = (Button)findViewById(R.id.button1);

        mButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                 PrintManager printManager = (PrintManager)getSystemService(Context.PRINT_SERVICE);
                String jobName =  " Document";
                printManager.print(jobName, pda, null);
            }
        });
    }


    public void openDocument(String name) {

        Intent intent = new Intent(android.content.Intent.ACTION_VIEW);
        File file = new File(name);
        String extension = android.webkit.MimeTypeMap.getFileExtensionFromUrl(Uri.fromFile(file).toString());
        String mimetype = android.webkit.MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
        intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

        if (extension.equalsIgnoreCase("") || mimetype == null) {
            // if there is no extension or there is no definite mimetype, still try to open the file
            intent.setDataAndType(Uri.fromFile(file), "text/*");
        }
        else {
            intent.setDataAndType(Uri.fromFile(file), mimetype);
        }

        // custom message for the intent
        startActivityForResult((Intent.createChooser(intent, "Choose an Application:")), Result_code);
        //startActivityForResult(intent, Result_code);
        //Toast.makeText(getApplicationContext(),"There are no email clients installed.", Toast.LENGTH_SHORT).show();
    }


    @SuppressLint("NewApi")
    PrintDocumentAdapter pda = new PrintDocumentAdapter(){

        @Override
        public void onWrite(PageRange[] pages, ParcelFileDescriptor destination, CancellationSignal cancellationSignal, WriteResultCallback callback){
            InputStream input = null;
            OutputStream output = null;

            try {
                String filename = Environment.getExternalStorageDirectory()    + "/" + "Holiday.pdf";
                File file = new File(filename);
                input = new FileInputStream(file);
                output = new FileOutputStream(destination.getFileDescriptor());

                byte[] buf = new byte[1024];
                int bytesRead;

                while ((bytesRead = input.read(buf)) > 0) {
                     output.write(buf, 0, bytesRead);
                }

                callback.onWriteFinished(new PageRange[]{PageRange.ALL_PAGES});
            }
            catch (FileNotFoundException ee){
                //Catch exception
            }
            catch (Exception e) {
                //Catch exception
            }
            finally {
                try {
                    input.close();
                    output.close();
                }
                catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        @Override
        public void onLayout(PrintAttributes oldAttributes, PrintAttributes newAttributes, CancellationSignal cancellationSignal, LayoutResultCallback callback, Bundle extras){

            if (cancellationSignal.isCanceled()) {
                callback.onLayoutCancelled();
                return;
            }

           // int pages = computePageCount(newAttributes);

            PrintDocumentInfo pdi = new PrintDocumentInfo.Builder("Name of file").setContentType(PrintDocumentInfo.CONTENT_TYPE_DOCUMENT).build();

            callback.onLayoutFinished(pdi, true);
        }
    };
}

How to verify a Text present in the loaded page through WebDriver

Below code is most suitable way to verify a text on page. You can use any one out of 8 locators as per your convenience.

String Verifytext= driver.findElement(By.tagName("body")).getText().trim(); Assert.assertEquals(Verifytext, "Paste the text here which needs to be verified");

MYSQL order by both Ascending and Descending sorting

I don't understand what the meaning of ordering with the same column ASC and DESC in the same ORDER BY, but this how you can do it: naam DESC, naam ASC like so:

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

How do I get list of all tables in a database using TSQL?

SELECT sobjects.name
FROM sysobjects sobjects
WHERE sobjects.xtype = 'U'

Here is a list of other object types you can search for as well:

  • AF: Aggregate function (CLR)
  • C: CHECK constraint
  • D: Default or DEFAULT constraint
  • F: FOREIGN KEY constraint
  • L: Log
  • FN: Scalar function
  • FS: Assembly (CLR) scalar-function
  • FT: Assembly (CLR) table-valued function
  • IF: In-lined table-function
  • IT: Internal table
  • P: Stored procedure
  • PC: Assembly (CLR) stored-procedure
  • PK: PRIMARY KEY constraint (type is K)
  • RF: Replication filter stored procedure
  • S: System table
  • SN: Synonym
  • SQ: Service queue
  • TA: Assembly (CLR) DML trigger
  • TF: Table function
  • TR: SQL DML Trigger
  • TT: Table type
  • U: User table
  • UQ: UNIQUE constraint (type is K)
  • V: View
  • X: Extended stored procedure

String's Maximum length in Java - calling length() method

As mentioned in Takahiko Kawasaki's answer, java represents Unicode strings in the form of modified UTF-8 and in JVM-Spec CONSTANT_UTF8_info Structure, 2 bytes are allocated to length (and not the no. of characters of String).
To extend the answer, the ASM jvm bytecode library's putUTF8 method, contains this:

public ByteVector putUTF8(final String stringValue) {
    int charLength = stringValue.length();
    if (charLength > 65535) {   
   // If no. of characters> 65535, than however UTF-8 encoded length, wont fit in 2 bytes.
      throw new IllegalArgumentException("UTF8 string too large");
    }
    for (int i = 0; i < charLength; ++i) {
      char charValue = stringValue.charAt(i);
      if (charValue >= '\u0001' && charValue <= '\u007F') {
        // Unicode code-point encoding in utf-8 fits in 1 byte.
        currentData[currentLength++] = (byte) charValue;
      } else {
        // doesnt fit in 1 byte.
        length = currentLength;
        return encodeUtf8(stringValue, i, 65535);
      }
    }
    ...
}

But when code-point mapping > 1byte, it calls encodeUTF8 method:

final ByteVector encodeUtf8(final String stringValue, final int offset, final int maxByteLength /*= 65535 */) {
    int charLength = stringValue.length();
    int byteLength = offset;
    for (int i = offset; i < charLength; ++i) {
      char charValue = stringValue.charAt(i);
      if (charValue >= 0x0001 && charValue <= 0x007F) {
        byteLength++;
      } else if (charValue <= 0x07FF) {
        byteLength += 2;
      } else {
        byteLength += 3;
      }
    }
   ...
}

In this sense, the max string length is 65535 bytes, i.e the utf-8 encoding length. and not char count
You can find the modified-Unicode code-point range of JVM, from the above utf8 struct link.

Dynamically updating plot in matplotlib

Is there a way in which I can update the plot just by adding more point[s] to it...

There are a number of ways of animating data in matplotlib, depending on the version you have. Have you seen the matplotlib cookbook examples? Also, check out the more modern animation examples in the matplotlib documentation. Finally, the animation API defines a function FuncAnimation which animates a function in time. This function could just be the function you use to acquire your data.

Each method basically sets the data property of the object being drawn, so doesn't require clearing the screen or figure. The data property can simply be extended, so you can keep the previous points and just keep adding to your line (or image or whatever you are drawing).

Given that you say that your data arrival time is uncertain your best bet is probably just to do something like:

import matplotlib.pyplot as plt
import numpy

hl, = plt.plot([], [])

def update_line(hl, new_data):
    hl.set_xdata(numpy.append(hl.get_xdata(), new_data))
    hl.set_ydata(numpy.append(hl.get_ydata(), new_data))
    plt.draw()

Then when you receive data from the serial port just call update_line.

Syntax for an If statement using a boolean

You can change the value of a bool all you want. As for an if:

if randombool == True:

works, but you can also use:

if randombool:

If you want to test whether something is false you can use:

if randombool == False

but you can also use:

if not randombool:

Get most recent file in a directory on Linux

Shorted variant based on dmckee's answer:

ls -t | head -1

Redis - Connect to Remote Server

Orabig is correct.

You can bind 10.0.2.15 in Ubuntu (VirtualBox) then do a port forwarding from host to guest Ubuntu.

in /etc/redis/redis.conf

bind 10.0.2.15

then, restart redis:

sudo systemctl restart redis

It shall work!

How can I suppress the newline after a print statement?

There's some information on printing without newline here.

In Python 3.x we can use ‘end=’ in the print function. This tells it to end the string with a character of our choosing rather than ending with a newline. For example:

print("My 1st String", end=","); print ("My 2nd String.")

This results in:

My 1st String, My 2nd String.

In nodeJs is there a way to loop through an array without using array size?

Use Iterators...

var myarray = ['hello', ' hello again'];
processArray(myarray[Symbol.iterator](), () => {
    console.log('all done')
})
function processArray(iter, cb) {
    var curr = iter.next()
    if(curr.done)
        return cb()
    console.log(curr.value)
    processArray(iter, cb)
}

More in depth overview: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols

How to find all duplicate from a List<string>?

If you're looking for a more generic method:

public static List<U> FindDuplicates<T, U>(this List<T> list, Func<T, U> keySelector)
    {
        return list.GroupBy(keySelector)
            .Where(group => group.Count() > 1)
            .Select(group => group.Key).ToList();
    }

EDIT: Here's an example:

public class Person {
    public string Name {get;set;}
    public int Age {get;set;}
}

List<Person> list = new List<Person>() { new Person() { Name = "John", Age = 22 }, new Person() { Name = "John", Age = 30 }, new Person() { Name = "Jack", Age = 30 } };

var duplicateNames = list.FindDuplicates(p => p.Name);
var duplicateAges = list.FindDuplicates(p => p.Age);

foreach(var dupName in duplicateNames) {
    Console.WriteLine(dupName); // Will print out John
}

foreach(var dupAge in duplicateAges) {
    Console.WriteLine(dupAge); // Will print out 30
}

How to create PDFs in an Android app?

A bit late and I have not yet tested it yet myself but another library that is under the BSD license is Android PDF Writer.

Update I have tried the library myself. Works ok with simple pdf generations (it provide methods for adding text, lines, rectangles, bitmaps, fonts). The only problem is that the generated PDF is stored in a String in memory, this may cause memory issues in large documents.

What's "tools:context" in Android layout files?

This attribute helps to get the best knowledge of the activity associated with your layout. This is also useful when you have to add onClick handlers on a view using QuickFix.

tools:context=".MainActivity"

MongoDB: How to query for records where field is null or not set?

Seems you can just do single line:

{ "sent_at": null }

What are .a and .so files?

.a are static libraries. If you use code stored inside them, it's taken from them and embedded into your own binary. In Visual Studio, these would be .lib files.

.so are dynamic libraries. If you use code stored inside them, it's not taken and embedded into your own binary. Instead it's just referenced, so the binary will depend on them and the code from the so file is added/loaded at runtime. In Visual Studio/Windows these would be .dll files (with small .lib files containing linking information).

How can I tell gcc not to inline a function?

You want the gcc-specific noinline attribute.

This function attribute prevents a function from being considered for inlining. If the function does not have side-effects, there are optimizations other than inlining that causes function calls to be optimized away, although the function call is live. To keep such calls from being optimized away, put asm ("");

Use it like this:

void __attribute__ ((noinline)) foo() 
{
  ...
}

How do I create a comma-separated list from an array in PHP?

This is how I've been doing it:

$arr = array(1,2,3,4,5,6,7,8,9);

$string = rtrim(implode(',', $arr), ',');

echo $string;

Output:

1,2,3,4,5,6,7,8,9

Live Demo: http://ideone.com/EWK1XR

EDIT: Per @joseantgv's comment, you should be able to remove rtrim() from the above example. I.e:

$string = implode(',', $arr);

Most Useful Attributes

In our current project, we use

[ComVisible(false)]

It controls accessibility of an individual managed type or member, or of all types within an assembly, to COM.

More Info

json.decoder.JSONDecodeError: Extra data: line 2 column 1 (char 190)

You have two records in your json file, and json.loads() is not able to decode more than one. You need to do it record by record.

See Python json.loads shows ValueError: Extra data

OR you need to reformat your json to contain an array:

{
    "foo" : [
       {"name": "XYZ", "address": "54.7168,94.0215", "country_of_residence": "PQR", "countries": "LMN;PQRST", "date": "28-AUG-2008", "type": null},
       {"name": "OLMS", "address": null, "country_of_residence": null, "countries": "Not identified;No", "date": "23-FEB-2017", "type": null}
    ]
}

would be acceptable again. But there cannot be several top level objects.

jQuery: How can I show an image popup onclick of the thumbnail?

prettyPhoto is a jQuery lightbox clone. Not only does it support images, it also support for videos, flash, YouTube, iframes and ajax. It’s a full blown media lightbox

Set maxlength in Html Textarea

<p>
   <textarea id="msgc" onkeyup="cnt(event)" rows="1" cols="1"></textarea> 
</p> 
<p id="valmess2" style="color:red" ></p>

function cnt(event)
{ 
 document.getElementById("valmess2").innerHTML=""; // init and clear if b < max     
allowed character 

 a = document.getElementById("msgc").value; 
 b = a.length; 
 if (b > 400)
  { 
   document.getElementById("valmess2").innerHTML="the max length of 400 characters is 
reached, you typed in  " + b + "characters"; 
  } 
}

maxlength is only valid for HTML5. For HTML/XHTML you have to use JavaScript and/or PHP. With PHP you can use strlen for example.This example indicates only the max length, it's NOT blocking the input.

How do I save JSON to local text file

It's my solution to save local data to txt file.

_x000D_
_x000D_
function export2txt() {_x000D_
  const originalData = {_x000D_
    members: [{_x000D_
        name: "cliff",_x000D_
        age: "34"_x000D_
      },_x000D_
      {_x000D_
        name: "ted",_x000D_
        age: "42"_x000D_
      },_x000D_
      {_x000D_
        name: "bob",_x000D_
        age: "12"_x000D_
      }_x000D_
    ]_x000D_
  };_x000D_
_x000D_
  const a = document.createElement("a");_x000D_
  a.href = URL.createObjectURL(new Blob([JSON.stringify(originalData, null, 2)], {_x000D_
    type: "text/plain"_x000D_
  }));_x000D_
  a.setAttribute("download", "data.txt");_x000D_
  document.body.appendChild(a);_x000D_
  a.click();_x000D_
  document.body.removeChild(a);_x000D_
}
_x000D_
<button onclick="export2txt()">Export data to local txt file</button>
_x000D_
_x000D_
_x000D_

Get Category name from Post ID

echo '<p>'. get_the_category( $id )[0]->name .'</p>';

is what you maybe looking for.

How to specify jackson to only use fields - preferably globally

@since 2.10 version we can use JsonMapper.Builder and accepted answer could look like:

JsonMapper mapper = JsonMapper.builder()
    .visibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY)
    .visibility(PropertyAccessor.GETTER, JsonAutoDetect.Visibility.NONE)
    .visibility(PropertyAccessor.SETTER, JsonAutoDetect.Visibility.NONE)
    .visibility(PropertyAccessor.CREATOR, JsonAutoDetect.Visibility.NONE)
    .build();

ComboBox SelectedItem vs SelectedValue

I suspect that the SelectedItem property of the ComboBox does not change until the control has been validated (which occurs when the control loses focus), whereas the SelectedValue property changes whenever the user selects an item.

Here is a reference to the focus events that occur on controls:

http://msdn.microsoft.com/en-us/library/system.windows.forms.control.validated.aspx

Where can I download JSTL jar

If youre using Maven, here's something for your pom.xml file

<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>

Show SOME invisible/whitespace characters in Eclipse

Unfortunately, you can only turn on all invisible (whitespace) characters at the same time. I suggest you file an enhancement request but I doubt they will pick it up.

The text component in Eclipse is very complicated as it is and they are not keen on making them even worse.

[UPDATE] This has been fixed in Eclipse 3.7: Go to Window > Preferences > General > Editors > Text Editors

Click on the link "whitespace characters" to fine tune what should be shown.

Kudos go to John Isaacks

postgres: upgrade a user to be a superuser?

alter user username superuser;

Remove all elements contained in another array

The filter method should do the trick:

const myArray = ['a', 'b', 'c', 'd', 'e', 'f', 'g'];
const toRemove = ['b', 'c', 'g'];

// ES5 syntax
const filteredArray = myArray.filter(function(x) { 
  return toRemove.indexOf(x) < 0;
});

If your toRemove array is large, this sort of lookup pattern can be inefficient. It would be more performant to create a map so that lookups are O(1) rather than O(n).

const toRemoveMap = toRemove.reduce(
  function(memo, item) {
    memo[item] = memo[item] || true;
    return memo;
  },
  {} // initialize an empty object
);

const filteredArray = myArray.filter(function (x) {
  return toRemoveMap[x];
});

// or, if you want to use ES6-style arrow syntax:
const toRemoveMap = toRemove.reduce((memo, item) => ({
  ...memo,
  [item]: true
}), {});

const filteredArray = myArray.filter(x => toRemoveMap[x]);

How to alias a table in Laravel Eloquent queries (or using Query Builder)?

To use aliases on eloquent models modify your code like this:

Item
    ::from( 'items as items_alias' )
    ->join( 'attachments as att', DB::raw( 'att.item_id' ), '=', DB::raw( 'items_alias.id' ) )
    ->select( DB::raw( 'items_alias.*' ) )
    ->get();

This will automatically add table prefix to table names and returns an instance of Items model. not a bare query result. Adding DB::raw prevents laravel from adding table prefixes to aliases.

How to show row number in Access query like ROW_NUMBER in SQL

One way to do this with MS Access is with a subquery but it does not have anything like the same functionality:

SELECT a.ID, 
       a.AText, 
       (SELECT Count(ID) 
        FROM table1 b WHERE b.ID <= a.ID 
        AND b.AText Like "*a*") AS RowNo
FROM Table1 AS a
WHERE a.AText Like "*a*"
ORDER BY a.ID;

How to loop through an associative array and get the key?

While arguably being less clear this method is faster by roughly a factor of roughly 3.5 (At least on the box I used to test)

$foo = array(
    1 => "Value1",
    2 => "Value2",
    10 => "Value10"
);
while($bar = each($foo)){
    echo $bar[0] . " => " . $bar[1];
}

I would imagine that this is due to the fact the foreach copies the entire array before iterating over it.

error MSB6006: "cmd.exe" exited with code 1

I had the same problem today, while I was upgrading some VC6 project to VC2012.

In my case, it was because some of the operation in Custom Built Steps failed. In project properties, go to Custom Build Step, you can see there maybe some something in command line edit box. Open a windows prompt and paste the command to it. Run, check if there is something wrong and fix it.

If there is no command line in the project property Custom Built Step, maybe you should check properties of every single file of the project.

If the command line has some macro, replace it with an actual value.

Or you can echo the command in VS output window:

  • cd %(somedir)%
  • echo %(somedir)%

You won't miss it this way.

Placeholder in IE9

I think this is what you are looking for: jquery-html5-placeholder-fix

This solution uses feature detection (via modernizr) to determine if placeholder is supported. If not, adds support (via jQuery).

Why does corrcoef return a matrix?

You can use the following function to return only the correlation coefficient:

def pearson_r(x, y):
"""Compute Pearson correlation coefficient between two arrays."""

   # Compute correlation matrix
   corr_mat = np.corrcoef(x, y)

   # Return entry [0,1]
   return corr_mat[0,1]

Better naming in Tuple classes than "Item1", "Item2"

No, you can't name the tuple members.

The in-between would be to use ExpandoObject instead of Tuple.

Scala how can I count the number of occurrences in a list

scala collections do have count: list.count(_ == 2)

is inaccessible due to its protection level

The reason being you can not access protected member data through the instance of the class.

Reason why it is not allowed is explained in this blog

Is it possible to set the stacking order of pseudo-elements below their parent element?

Set the z-index of the :before or :after pseudo element to -1 and give it a position that honors the z-index property (absolute, relative, or fixed). This works because the pseudo element's z-index is relative to its parent element, rather than <html>, which is the default for other elements. Which makes sense because they are child elements of <html>.

The problem I was having (that lead me to this question and the accepted answer above) was that I was trying to use a :after pseudo element to get fancy with a background to an element with z-index of 15, and even when set with a z-index of 14, it was still being rendered on top of its parent. This is because, in that stacking context, it's parent has a z-index of 0.

Hopefully that helps clarify a little what's going on.

Difference between signed / unsigned char

Representation is the same, the meaning is different. e.g, 0xFF, it both represented as "FF". When it is treated as "char", it is negative number -1; but it is 255 as unsigned. When it comes to bit shifting, it is a big difference since the sign bit is not shifted. e.g, if you shift 255 right 1 bit, it will get 127; shifting "-1" right will be no effect.

Retrieve a Fragment from a ViewPager

For grabbing fragments out of a ViewPager there are a lot of answers on here and on other related SO threads / blogs. Everyone I have seen is broken, and they generally seem to fall into one of the two types listed below. There are some other valid solutions if you only want to grab the current fragment, like this other answer on this thread.

If using FragmentPagerAdapter see below. If using FragmentStatePagerAdapter its worth looking at this. Grabbing indexes that are not the current one in a FragmentStateAdapter is not as useful as by the nature of it these will be completely torn down went out of view / out of offScreenLimit bounds.

THE UNHAPPY PATHS

Wrong: Maintain your own internal list of fragments, added to when FragmentPagerAdapter.getItem() is called

  • Usually using a SparseArray or Map
  • Not one of the many examples I have seen accounts for lifecycle events so this solution is fragile. As getItem is only called the first time a page is scrolled to (or obtained if your ViewPager.setOffscreenPageLimit(x) > 0) in the ViewPager, if the hosting Activity / Fragment is killed or restarted then the internal SpaseArray will be wiped out when the custom FragmentPagerActivity is recreated, but behind the scenes the ViewPagers internal fragments will be recreated, and getItem will NOT be called for any of the indexes, so the ability to get a fragment from index will be lost forever. You can account for this by saving out and restoring these fragment references via FragmentManager.getFragment() and putFragment but this starts to get messy IMHO.

Wrong: Construct your own tag id matching what is used under the hood in FragmentPagerAdapter and use this to retrieve the page Fragments from the FragmentManager

  • This is better insomuch as it copes with the losing-fragment-references problem in the first internal-array solution, but as rightly pointed out in the answers above and elsewhere on the net - it feels hacky as its a private method internal to ViewPager that could change at any time or for any OS version.

The method thats recreated for this solution is

private static String makeFragmentName(int viewId, long id) {
    return "android:switcher:" + viewId + ":" + id;
}

A HAPPY PATH: ViewPager.instantiateItem()

A similar approach to getItem() above but non-lifecycle-breaking is to this is to hook into instantiateItem() instead of getItem() as the former will be called everytime that index is created / accessed. See this answer

A HAPPY PATH: Construct your own FragmentViewPager

Construct your own FragmentViewPager class from the source of the latest support lib and change the method used internally to generate the fragment tags. You can replace it with the below. This has the advantage that you know the tag creation will never change and your not relying on a private api / method, which is always dangerous.

/**
 * @param containerViewId the ViewPager this adapter is being supplied to
 * @param id pass in getItemId(position) as this is whats used internally in this class
 * @return the tag used for this pages fragment
 */
public static String makeFragmentName(int containerViewId, long id) {
    return "android:switcher:" + containerViewId + ":" + id;
}

Then as the doc says, when you want to grab a fragment used for an index just call something like this method (which you can put in the custom FragmentPagerAdapter or a subclass) being aware the result may be null if getItem has not yet been called for that page i.e. its not been created yet.

/**
 * @return may return null if the fragment has not been instantiated yet for that position - this depends on if the fragment has been viewed
 * yet OR is a sibling covered by {@link android.support.v4.view.ViewPager#setOffscreenPageLimit(int)}. Can use this to call methods on
 * the current positions fragment.
 */
public @Nullable Fragment getFragmentForPosition(int position)
{
    String tag = makeFragmentName(mViewPager.getId(), getItemId(position));
    Fragment fragment = getSupportFragmentManager().findFragmentByTag(tag);
    return fragment;
}

This is a simple solution and solves the issues in the other two solutions found everywhere on the web

Start an external application from a Google Chrome Extension?

You can't launch arbitrary commands, but if your users are willing to go through some extra setup, you can use custom protocols.

E.g. you have the users set things up so that some-app:// links start "SomeApp", and then in my-awesome-extension you open a tab pointing to some-app://some-data-the-app-wants, and you're good to go!

Toggle Class in React

Toggle function in react

At first you should create constructor like this

constructor(props) {
        super(props);
        this.state = {
            close: true,
        };
    }

Then create a function like this

yourFunction = () => {
        this.setState({
            close: !this.state.close,
        });
    };

then use this like

render() {
        const {close} = this.state;
        return (

            <Fragment>

                 <div onClick={() => this.yourFunction()}></div>

                 <div className={close ? "isYourDefaultClass" : "isYourOnChangeClass"}></div>

            </Fragment>
        )
    }
}

Please give better solutions

MYSQL Sum Query with IF Condition

Try with a CASE in this way :

SUM(CASE 
    WHEN PaymentType = "credit card" 
    THEN TotalAmount 
    ELSE 0 
END) AS CreditCardTotal,

Should give what you are looking for ...

ASP.net Repeater get current index, pointer, or counter

To display the item number on the repeater you can use the Container.ItemIndex property.

<asp:repeater id="rptRepeater" runat="server">
    <itemtemplate>
        Item <%# Container.ItemIndex + 1 %>| <%# Eval("Column1") %>
    </itemtemplate>
    <separatortemplate>
        <br />
    </separatortemplate>
</asp:repeater>

How long to brute force a salted SHA-512 hash? (salt provided)

There isn't a single answer to this question as there are too many variables, but SHA2 is not yet really cracked (see: Lifetimes of cryptographic hash functions) so it is still a good algorithm to use to store passwords in. The use of salt is good because it prevents attack from dictionary attacks or rainbow tables. Importance of a salt is that it should be unique for each password. You can use a format like [128-bit salt][512-bit password hash] when storing the hashed passwords.

The only viable way to attack is to actually calculate hashes for different possibilities of password and eventually find the right one by matching the hashes.

To give an idea about how many hashes can be done in a second, I think Bitcoin is a decent example. Bitcoin uses SHA256 and to cut it short, the more hashes you generate, the more bitcoins you get (which you can trade for real money) and as such people are motivated to use GPUs for this purpose. You can see in the hardware overview that an average graphic card that costs only $150 can calculate more than 200 million hashes/s. The longer and more complex your password is, the longer time it will take. Calculating at 200M/s, to try all possibilities for an 8 character alphanumberic (capital, lower, numbers) will take around 300 hours. The real time will most likely less if the password is something eligible or a common english word.

As such with anything security you need to look at in context. What is the attacker's motivation? What is the kind of application? Having a hash with random salt for each gives pretty good protection against cases where something like thousands of passwords are compromised.

One thing you can do is also add additional brute force protection by slowing down the hashing procedure. As you only hash passwords once, and the attacker has to do it many times, this works in your favor. The typical way to do is to take a value, hash it, take the output, hash it again and so forth for a fixed amount of iterations. You can try something like 1,000 or 10,000 iterations for example. This will make it that many times times slower for the attacker to find each password.

Get protocol + host name from URL

This is a bit obtuse, but uses urlparse in both directions:

import urlparse
def uri2schemehostname(uri):
    urlparse.urlunparse(urlparse.urlparse(uri)[:2] + ("",) * 4)

that odd ("",) * 4 bit is because urlparse expects a sequence of exactly len(urlparse.ParseResult._fields) = 6

echo that outputs to stderr

If you don't mind logging the message also to syslog, the not_so_ugly way is:

logger -s $msg

The -s option means: "Output the message to standard error as well as to the system log."

Count rows with not empty value

A simpler solution that works for me:

=COUNTIFS(A:A;"<>"&"")

It counts both numbers, strings, dates, etc that are not empty

Stylesheet not updating

I had same issue. One of the reasons was, my application was cached and I was performing local build.

I would prefer deleting the css file and re-adding it again with changes if none of the above comments work.