Programs & Examples On #Spatial index

Spatial Indexes are data structures used in SQL and other databases to enhance and optimize the execution of queries that use the data.

Java: Most efficient method to iterate over all elements in a org.w3c.dom.Document?

Basically you have two ways to iterate over all elements:

1. Using recursion (the most common way I think):

public static void main(String[] args) throws SAXException, IOException,
        ParserConfigurationException, TransformerException {

    DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory
        .newInstance();
    DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
    Document document = docBuilder.parse(new File("document.xml"));
    doSomething(document.getDocumentElement());
}

public static void doSomething(Node node) {
    // do something with the current node instead of System.out
    System.out.println(node.getNodeName());

    NodeList nodeList = node.getChildNodes();
    for (int i = 0; i < nodeList.getLength(); i++) {
        Node currentNode = nodeList.item(i);
        if (currentNode.getNodeType() == Node.ELEMENT_NODE) {
            //calls this method for all the children which is Element
            doSomething(currentNode);
        }
    }
}

2. Avoiding recursion using getElementsByTagName() method with * as parameter:

public static void main(String[] args) throws SAXException, IOException,
        ParserConfigurationException, TransformerException {

    DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory
            .newInstance();
    DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
    Document document = docBuilder.parse(new File("document.xml"));

    NodeList nodeList = document.getElementsByTagName("*");
    for (int i = 0; i < nodeList.getLength(); i++) {
        Node node = nodeList.item(i);
        if (node.getNodeType() == Node.ELEMENT_NODE) {
            // do something with the current element
            System.out.println(node.getNodeName());
        }
    }
}

I think these ways are both efficient.
Hope this helps.

{"<user xmlns=''> was not expected.} Deserializing Twitter XML

My issue was that the root element actually has a xmlns="abc123"

So had to make XmlRoot("elementname",NameSpace="abc123")

Multiline input form field using Bootstrap

I think the problem is that you are using type="text" instead of textarea. What you want is:

<textarea class="span6" rows="3" placeholder="What's up?" required></textarea>

To clarify, a type="text" will always be one row, where-as a textarea can be multiple.

understanding private setters

Yes, you are using encapsulation by using properties, but there are more nuances to encapsulation than just taking control over how properties are read and written. Denying a property to be set from outside the class can be useful both for robustness and performance.

An immutable class is a class that doesn't change once it's created, so private setters (or no setters at all) is needed to protect the properties.

Private setters came into more frequent use with the property shorthand that was instroduced in C# 3. In C# 2 the setter was often just omitted, and the private data accessed directly when set.

This property:

public int Size { get; private set; }

is the same as:

private int _size;
public int Size {
  get { return _size; }
  private set { _size = value; }
}

except, the name of the backing variable is internally created by the compiler, so you can't access it directly.

With the shorthand property the private setter is needed to create a read-only property, as you can't access the backing variable directly.

php hide ALL errors

To hide errors only from users but displaying logs errors in apache log

error_reporting(E_ALL);
ini_set('display_errors', 0);

1 - Displaying error only in log
2 - hide from users

Git: How do I list only local branches?

just the plain command

git branch

How to escape double quotes in a title attribute

There is at least one situation where using single quotes will not work and that is if you are creating the markup "on the fly" from JavaScript. You use single quotes to contain the string and then any property in the markup can have double quotes for its value.

JUnit Eclipse Plugin?

It's built in Eclipse since ages. Which Eclipse version are you using? How were you trying to create a new JUnit test case? It should be File > New > Other > Java - JUnit - JUnit Test Case (you can eventually enter Filter text "junit").

How can I open a link in a new window?

This is not a very nice fix but it works:

CSS:

.new-tab-opener
{
    display: none;
}

HTML:

<a data-href="http://www.google.com/" href="javascript:">Click here</a>
<form class="new-tab-opener" method="get" target="_blank"></form>

Javascript:

$('a').on('click', function (e) {    
    var f = $('.new-tab-opener');
    f.attr('action', $(this).attr('data-href'));
    f.submit();
});

Live example: http://jsfiddle.net/7eRLb/

How to create a JSON object

Although the other answers posted here work, I find the following approach more natural:

$obj = (object) [
    'aString' => 'some string',
    'anArray' => [ 1, 2, 3 ]
];

echo json_encode($obj);

How can a file be copied?

In Python, you can copy the files using


import os
import shutil
import subprocess

1) Copying files using shutil module

shutil.copyfile signature

shutil.copyfile(src_file, dest_file, *, follow_symlinks=True)

# example    
shutil.copyfile('source.txt', 'destination.txt')

shutil.copy signature

shutil.copy(src_file, dest_file, *, follow_symlinks=True)

# example
shutil.copy('source.txt', 'destination.txt')

shutil.copy2 signature

shutil.copy2(src_file, dest_file, *, follow_symlinks=True)

# example
shutil.copy2('source.txt', 'destination.txt')  

shutil.copyfileobj signature

shutil.copyfileobj(src_file_object, dest_file_object[, length])

# example
file_src = 'source.txt'  
f_src = open(file_src, 'rb')

file_dest = 'destination.txt'  
f_dest = open(file_dest, 'wb')

shutil.copyfileobj(f_src, f_dest)  

2) Copying files using os module

os.popen signature

os.popen(cmd[, mode[, bufsize]])

# example
# In Unix/Linux
os.popen('cp source.txt destination.txt') 

# In Windows
os.popen('copy source.txt destination.txt')

os.system signature

os.system(command)


# In Linux/Unix
os.system('cp source.txt destination.txt')  

# In Windows
os.system('copy source.txt destination.txt')

3) Copying files using subprocess module

subprocess.call signature

subprocess.call(args, *, stdin=None, stdout=None, stderr=None, shell=False)

# example (WARNING: setting `shell=True` might be a security-risk)
# In Linux/Unix
status = subprocess.call('cp source.txt destination.txt', shell=True) 

# In Windows
status = subprocess.call('copy source.txt destination.txt', shell=True)

subprocess.check_output signature

subprocess.check_output(args, *, stdin=None, stderr=None, shell=False, universal_newlines=False)

# example (WARNING: setting `shell=True` might be a security-risk)
# In Linux/Unix
status = subprocess.check_output('cp source.txt destination.txt', shell=True)

# In Windows
status = subprocess.check_output('copy source.txt destination.txt', shell=True)

Reading a text file with SQL Server

What does your text file look like?? Each line a record?

You'll have to check out the BULK INSERT statement - that should look something like:

BULK INSERT dbo.YourTableName
FROM 'D:\directory\YourFileName.csv'
WITH
(
  CODEPAGE = '1252',
  FIELDTERMINATOR = ';',
  CHECK_CONSTRAINTS
) 

Here, in my case, I'm importing a CSV file - but you should be able to import a text file just as well.

From the MSDN docs - here's a sample that hopefully works for a text file with one field per row:

BULK INSERT dbo.temp 
   FROM 'c:\temp\file.txt'
   WITH 
      (
         ROWTERMINATOR ='\n'
      )

Seems to work just fine in my test environment :-)

How to get the list of all printers in computer

Try this:

foreach (string printer in System.Drawing.Printing.PrinterSettings.InstalledPrinters)
{
    MessageBox.Show(printer);
}

Removing Spaces from a String in C?

#include<stdio.h>
#include<string.h>
main()
{
  int i=0,n;
  int j=0;
  char str[]="        Nar ayan singh              ";
  char *ptr,*ptr1;
  printf("sizeof str:%ld\n",strlen(str));
  while(str[i]==' ')
   {
     memcpy (str,str+1,strlen(str)+1);
   }
  printf("sizeof str:%ld\n",strlen(str));
  n=strlen(str);
  while(str[n]==' ' || str[n]=='\0')
    n--;
  str[n+1]='\0';
  printf("str:%s ",str);
  printf("sizeof str:%ld\n",strlen(str));
}

How to resolve "local edit, incoming delete upon update" message

Try to resolve the conflict using

svn resolve --accept=working PATH

How do I check if a string contains another string in Objective-C?

-(Bool)checkIf:(String)parentString containsSubstring:(String)checkString {
    NSRange textRange =[parentString rangeOfString:checkString];
    return textRange.location != NSNotFound // returns true if parent string contains substring else returns false
  }

using jquery $.ajax to call a PHP function

I developed a jQuery plugin that allows you to call any core PHP function or even user defined PHP functions as methods of the plugin: jquery.php

After including jquery and jquery.php in the head of our document and placing request_handler.php on our server we would start using the plugin in the manner described below.

For ease of use reference the function in a simple manner:

    var P = $.fn.php;

Then initialize the plugin:

P('init', 
{
    // The path to our function request handler is absolutely required
    'path': 'http://www.YourDomain.com/jqueryphp/request_handler.php',

    // Synchronous requests are required for method chaining functionality
    'async': false,

    // List any user defined functions in the manner prescribed here
            // There must be user defined functions with these same names in your PHP
    'userFunctions': {

        languageFunctions: 'someFunc1 someFunc2'
    }
});             

And now some usage scenarios:

// Suspend callback mode so we don't work with the DOM
P.callback(false);

// Both .end() and .data return data to variables
var strLenA = P.strlen('some string').end();
var strLenB = P.strlen('another string').end();
var totalStrLen = strLenA + strLenB;
console.log( totalStrLen ); // 25

// .data Returns data in an array
var data1 = P.crypt("Some Crypt String").data();
console.log( data1 ); // ["$1$Tk1b01rk$shTKSqDslatUSRV3WdlnI/"]

Demonstrating PHP function chaining:

var data1 = P.strtoupper("u,p,p,e,r,c,a,s,e").strstr([], "C,A,S,E").explode(",", [], 2).data();
var data2 = P.strtoupper("u,p,p,e,r,c,a,s,e").strstr([], "C,A,S,E").explode(",", [], 2).end();
console.log( data1, data2 );

Demonstrating sending a JSON block of PHP pseudo-code:

var data1 = 
        P.block({
    $str: "Let's use PHP's file_get_contents()!",
    $opts: 
    [
        {
            http: {
                method: "GET",
                header: "Accept-language: en\r\n" +
                        "Cookie: foo=bar\r\n"
            }
        }
    ],
    $context: 
    {
        stream_context_create: ['$opts']
    },
    $contents: 
    {
        file_get_contents: ['http://www.github.com/', false, '$context']
    },
    $html: 
    {
        htmlentities: ['$contents']
    }
}).data();
    console.log( data1 );

The backend configuration provides a whitelist so you can restrict which functions can be called. There are a few other patterns for working with PHP described by the plugin as well.

How to bind event listener for rendered elements in Angular 2?

In order to add an EventListener to an element in angular 2+, we can use the method listen of the Renderer2 service (Renderer is deprecated, so use Renderer2):

listen(target: 'window'|'document'|'body'|any, eventName: string, callback: (event: any) => boolean | void): () => void

Example:

export class ListenDemo implements AfterViewInit { 
   @ViewChild('testElement') 
   private testElement: ElementRef;
   globalInstance: any;       

   constructor(private renderer: Renderer2) {
   }

   ngAfterViewInit() {
       this.globalInstance = this.renderer.listen(this.testElement.nativeElement, 'click', () => {
           this.renderer.setStyle(this.testElement.nativeElement, 'color', 'green');
       });
    }
}

Note:

When you use this method to add an event listener to an element in the dom, you should remove this event listener when the component is destroyed

You can do that this way:

ngOnDestroy() {
  this.globalInstance();
}

The way of use of ElementRef in this method should not expose your angular application to a security risk. for more on this referrer to ElementRef security risk angular 2

When using .net MVC RadioButtonFor(), how do you group so only one selection can be made?

In my case, I had a collection of radio buttons that needed to be in a group. I just included a 'Selected' property in the model. Then, in the loop to output the radiobuttons just do...

@Html.RadioButtonFor(m => Model.Selected, Model.Categories[i].Title)

This way, the name is the same for all radio buttons. When the form is posted, the 'Selected' property is equal to the category title (or id or whatever) and this can be used to update the binding on the relevant radiobutton, like this...

model.Categories.Find(m => m.Title.Equals(model.Selected)).Selected = true;

May not be the best way, but it does work.

MySql Query Replace NULL with Empty String in Select

Some of these built in functions should work:

Coalesce
Is Null
IfNull

Programmatically find the number of cores on a machine

Note that "number of cores" might not be a particularly useful number, you might have to qualify it a bit more. How do you want to count multi-threaded CPUs such as Intel HT, IBM Power5 and Power6, and most famously, Sun's Niagara/UltraSparc T1 and T2? Or even more interesting, the MIPS 1004k with its two levels of hardware threading (supervisor AND user-level)... Not to mention what happens when you move into hypervisor-supported systems where the hardware might have tens of CPUs but your particular OS only sees a few.

The best you can hope for is to tell the number of logical processing units that you have in your local OS partition. Forget about seeing the true machine unless you are a hypervisor. The only exception to this rule today is in x86 land, but the end of non-virtual machines is coming fast...

Display loading image while post with ajax

This is very simple and easily manage.

jQuery(document).ready(function(){
jQuery("#search").click(function(){
    jQuery("#loader").show("slow");
    jQuery("#response_result").hide("slow");
    jQuery.post(siteurl+"/ajax.php?q="passyourdata, function(response){
        setTimeout("finishAjax('response_result', '"+escape(response)+"')", 850);
            });
});

})
function finishAjax(id,response){ 
      jQuery("#loader").hide("slow");   
      jQuery('#response_result').html(unescape(response));
      jQuery("#"+id).show("slow");      
      return true;
}

Use JAXB to create Object from XML String

If you already have the xml, and comes more than one attribute, you can handle it as follows:

String output = "<ciudads><ciudad><idCiudad>1</idCiudad>
<nomCiudad>BOGOTA</nomCiudad></ciudad><ciudad><idCiudad>6</idCiudad>
<nomCiudad>Pereira</nomCiudad></ciudads>";
DocumentBuilder db = DocumentBuilderFactory.newInstance()
    .newDocumentBuilder();
InputSource is = new InputSource();
is.setCharacterStream(new StringReader(output));

Document doc = db.parse(is);
NodeList nodes = ((org.w3c.dom.Document) doc)
    .getElementsByTagName("ciudad");

for (int i = 0; i < nodes.getLength(); i++) {           
    Ciudad ciudad = new Ciudad();
    Element element = (Element) nodes.item(i);

    NodeList name = element.getElementsByTagName("idCiudad");
    Element element2 = (Element) name.item(0);
    ciudad.setIdCiudad(Integer
        .valueOf(getCharacterDataFromElement(element2)));

    NodeList title = element.getElementsByTagName("nomCiudad");
    element2 = (Element) title.item(0);
    ciudad.setNombre(getCharacterDataFromElement(element2));

    ciudades.getPartnerAccount().add(ciudad);
}
}

for (Ciudad ciudad1 : ciudades.getPartnerAccount()) {
System.out.println(ciudad1.getIdCiudad());
System.out.println(ciudad1.getNombre());
}

the method getCharacterDataFromElement is

public static String getCharacterDataFromElement(Element e) {
Node child = e.getFirstChild();
if (child instanceof CharacterData) {
CharacterData cd = (CharacterData) child;

return cd.getData();
}
return "";
}

Run CSS3 animation only once (at page loading)

If I understand correctly that you want to play the animation on A only once youu have to add

animation-iteration-count: 1

to the style for the a.

How do I run Google Chrome as root?

STEP 1: cd /opt/google/chrome

STEP 2: edit google-chrome file. gedit google-chrome

STEP 3: find this line: exec -a "$0" "$HERE/chrome" "$@".

Mostly this line is in the end of google-chrome file.

Comment it out like this : #exec -a "$0" "$HERE/chrome" "$@"

STEP 4:add a new line at the same place.

exec -a "$0" "$HERE/chrome" "$@" --user-data-dir

STEP 5: save google-chrome file and quit. And then you can use chrome as root user. Enjoy it!

How to solve npm install throwing fsevents warning on non-MAC OS?

I also had the same issue though am using MacOS. The issue is kind of bug. I solved this issue by repeatedly running the commands,

sudo npm cache clean --force 
sudo npm uninstall 
sudo npm install

One time it did not work but when I repeatedly cleaned the cache and after uninstalling npm, reinstalling npm, the error went off. I am using Angular 8 and this issue is common

Favicon not showing up in Google Chrome

Upload your favicon.ico to the root directory of your website and that should work with Chrome. Some browsers disregard the meta tag and just use /favicon.ico

Go figure?.....

Submitting a multidimensional array via POST with php

I made a function which handles arrays as well as single GET or POST values

function subVal($varName, $default=NULL,$isArray=FALSE ){ // $isArray toggles between (multi)array or single mode

    $retVal = "";
    $retArray = array();

    if($isArray) {
        if(isset($_POST[$varName])) {
            foreach ( $_POST[$varName] as $var ) {  // multidimensional POST array elements
                $retArray[]=$var;
            }
        }
        $retVal=$retArray;
    }

    elseif (isset($_POST[$varName]) )  {  // simple POST array element
        $retVal = $_POST[$varName];
    }

    else {
        if (isset($_GET[$varName]) ) {
            $retVal = $_GET[$varName];    // simple GET array element
        }
        else {
            $retVal = $default;
        }
    }

    return $retVal;

}

Examples:

$curr_topdiameter = subVal("topdiameter","",TRUE)[3];
$user_name = subVal("user_name","");

changing permission for files and folder recursively using shell command in mac

You can just use the -R (recursive) flag.

chmod -R 777 /Users/Test/Desktop/PATH

ImportError: Couldn't import Django

You can use python3 to run file, if you don't want to use virtualenv.python3 manage.py runserver

To install python3 look at this page

How to install trusted CA certificate on Android device?

There is a MUCH easier solution to this than posted here, or in related threads. If you are using a webview (as I am), you can achieve this by executing a JAVASCRIPT function within it. If you are not using a webview, you might want to create a hidden one for this purpose. Here's a function that works in just about any browser (or webview) to kickoff ca installation (generally through the shared os cert repository, including on a Droid). It uses a nice trick with iFrames. Just pass the url to a .crt file to this function:

function installTrustedRootCert( rootCertUrl ){
    id = "rootCertInstaller";
    iframe = document.getElementById( id );
    if( iframe != null ) document.body.removeChild( iframe );
    iframe = document.createElement( "iframe" );
    iframe.id = id;
    iframe.style.display = "none";
    document.body.appendChild( iframe );
    iframe.src = rootCertUrl;
}

UPDATE:

The iframe trick works on Droids with API 19 and up, but older versions of the webview won't work like this. The general idea still works though - just download/open the file with a webview and then let the os take over. This may be an easier and more universal solution (in the actual java now):

 public static void installTrustedRootCert( final String certAddress ){
     WebView certWebView = new WebView( instance_ );
     certWebView.loadUrl( certAddress );
 }

Note that instance_ is a reference to the Activity. This works perfectly if you know the url to the cert. In my case, however, I resolve that dynamically with the server side software. I had to add a fair amount of additional code to intercept a redirection url and call this in a manner which did not cause a crash based on a threading complication, but I won't add all that confusion here...

Detect if a Form Control option button is selected in VBA

You should remove .Value from all option buttons because option buttons don't hold the resultant value, the option group control does. If you omit .Value then the default interface will report the option button status, as you are expecting. You should write all relevant code under commandbutton_click events because whenever the commandbutton is clicked the option button action will run.

If you want to run action code when the optionbutton is clicked then don't write an if loop for that.

EXAMPLE:

Sub CommandButton1_Click
    If OptionButton1 = true then
        (action code...)
    End if
End sub

Sub OptionButton1_Click   
    (action code...)
End sub

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!

Transparent background in JPEG image

JPEG can't support transparency because it uses RGB color space. If you want transparency use a format that supports alpha values. Example PNG is an image format that uses RGBA color space where (r = red, g = green, b = blue, a = alpha value). Alpha value is used as an opacity measure, 0% is fully transparent and 100% is completely opaque. pixel.

How can I make Jenkins CI with Git trigger on pushes to master?

Generic Webhook Trigger Plugin can be configured with filters to achieve this.

When configured with

  • A variable named ref and expression $.ref.
  • A filter with text $ref and filter expression like ^refs/heads/master$.

Then that job will trigger for every push to master. No polling.

You probably want more values from the webhook to actually perform the build. Just add more variables, with JSONPath, to pick what you need.

There are some use cases here: https://github.com/jenkinsci/generic-webhook-trigger-plugin/tree/master/src/test/resources/org/jenkinsci/plugins/gwt/bdd

CASE WHEN statement for ORDER BY clause

CASE is an expression - it returns a single scalar value (per row). It can't return a complex part of the parse tree of something else, like an ORDER BY clause of a SELECT statement.

It looks like you just need:

ORDER BY 
CASE WHEN TblList.PinRequestCount <> 0 THEN TblList.PinRequestCount END desc,
CASE WHEN TblList.HighCallAlertCount <> 0 THEN TblList.HighCallAlertCount END desc, 
Case WHEN TblList.HighAlertCount <> 0 THEN TblList.HighAlertCount END DESC,
CASE WHEN TblList.MediumCallAlertCount <> 0 THEN TblList.MediumCallAlertCount END DESC,
Case WHEN TblList.MediumAlertCount <> 0 THEN TblList.MediumAlertCount END DESC,
TblList.LastName ASC, TblList.FirstName ASC, TblList.MiddleName ASC

Or possibly:

ORDER BY 
CASE
   WHEN TblList.PinRequestCount <> 0 THEN TblList.PinRequestCount
   WHEN TblList.HighCallAlertCount <> 0 THEN TblList.HighCallAlertCount
   WHEN TblList.HighAlertCount <> 0 THEN TblList.HighAlertCount
   WHEN TblList.MediumCallAlertCount <> 0 THEN TblList.MediumCallAlertCount
   WHEN TblList.MediumAlertCount <> 0 THEN TblList.MediumAlertCount
END desc,
TblList.LastName ASC, TblList.FirstName ASC, TblList.MiddleName ASC

It's a little tricky to tell which of the above (or something else) is what you're looking for because you've a) not explained what actual sort order you're trying to achieve, and b) not supplied any sample data and expected results, from which we could attempt to deduce the actual sort order you're trying to achieve.


This may be the answer we're looking for:

ORDER BY 
CASE
   WHEN TblList.PinRequestCount <> 0 THEN 5
   WHEN TblList.HighCallAlertCount <> 0 THEN 4
   WHEN TblList.HighAlertCount <> 0 THEN 3
   WHEN TblList.MediumCallAlertCount <> 0 THEN 2
   WHEN TblList.MediumAlertCount <> 0 THEN 1
END desc,
CASE
   WHEN TblList.PinRequestCount <> 0 THEN TblList.PinRequestCount
   WHEN TblList.HighCallAlertCount <> 0 THEN TblList.HighCallAlertCount
   WHEN TblList.HighAlertCount <> 0 THEN TblList.HighAlertCount
   WHEN TblList.MediumCallAlertCount <> 0 THEN TblList.MediumCallAlertCount
   WHEN TblList.MediumAlertCount <> 0 THEN TblList.MediumAlertCount
END desc,
TblList.LastName ASC, TblList.FirstName ASC, TblList.MiddleName ASC

Limit number of characters allowed in form input text field

<input type="text" maxlength="5">

the maximum amount of letters that can be in the input is 5.

What does "Error: object '<myvariable>' not found" mean?

While executing multiple lines of code in R, you need to first select all the lines of code and then click on "Run". This error usually comes up when we don't select our statements and click on "Run".

Google Maps: how to get country, state/province/region, city given a lat/long value?

@Szkíta Had a great solution by creating a function that gets the address parts in a named array. Here is a compiled solution for those who want to use plain JavaScript.

Function to convert results to the named array:

function getAddressParts(obj) {

    var address = [];

    obj.address_components.forEach( function(el) {
        address[el.types[0]] = el.short_name;
    });

    return address;

} //getAddressParts()

Geocode the LAT/LNG values:

geocoder.geocode( { 'location' : latlng }, function(results, status) {

    if (status == google.maps.GeocoderStatus.OK) {
        var addressParts =  getAddressParts(results[0]);

        // the city
        var city = addressParts.locality;

        // the state
        var state = addressParts.administrative_area_level_1;
    }

});

Bind class toggle to window scroll event

Directives are not "inside the angular world" as they say. So you have to use apply to get back into it when changing stuff

setup script exited with error: command 'x86_64-linux-gnu-gcc' failed with exit status 1

error: command 'x86_64-linux-gnu-gcc' failed with exit status 1

Lot of time I got the same error when installing M2Crypto & pygraphviz and installed all the things mention in the approved answer. But this below line solved all my problems with the other packages in approved answer too.

sudo apt-get install libssl-dev swig
sudo apt-get install -y graphviz-dev

This swig package saved my life as the solution for M2Crypto and graphviz-dev for pygraphviz. I hope this will help someone.

Use URI builder in Android or create URL with variables

Excellent answer from above turned into a simple utility method.

private Uri buildURI(String url, Map<String, String> params) {

    // build url with parameters.
    Uri.Builder builder = Uri.parse(url).buildUpon();
    for (Map.Entry<String, String> entry : params.entrySet()) {
        builder.appendQueryParameter(entry.getKey(), entry.getValue());
    }

    return builder.build();
}

Postman addon's like in firefox

I liked PostMan, it was the main reason why I kept using Chrome, now I'm good with HttpRequester

https://addons.mozilla.org/En-us/firefox/addon/httprequester/?src=search

How to implement and do OCR in a C# project?

Here's one: (check out http://hongouru.blogspot.ie/2011/09/c-ocr-optical-character-recognition.html or http://www.codeproject.com/Articles/41709/How-To-Use-Office-2007-OCR-Using-C for more info)

using MODI;
static void Main(string[] args)
{
    DocumentClass myDoc = new DocumentClass();
    myDoc.Create(@"theDocumentName.tiff"); //we work with the .tiff extension
    myDoc.OCR(MiLANGUAGES.miLANG_ENGLISH, true, true);

    foreach (Image anImage in myDoc.Images)
    {
        Console.WriteLine(anImage.Layout.Text); //here we cout to the console.
    }
}

How to include a child object's child object in Entity Framework 5

A good example of using the Generic Repository pattern and implementing a generic solution for this might look something like this.

public IList<TEntity> Get<TParamater>(IList<Expression<Func<TEntity, TParamater>>> includeProperties)

{

    foreach (var include in includeProperties)
     {

        query = query.Include(include);
     }

        return query.ToList();
}

Why should I use core.autocrlf=true in Git?

Update 2:

Xcode 9 appears to have a "feature" where it will ignore the file's current line endings, and instead just use your default line-ending setting when inserting lines into a file, resulting in files with mixed line endings.

I'm pretty sure this bug didn't exist in Xcode 7; not sure about Xcode 8. The good news is that it appears to be fixed in Xcode 10.

For the time it existed, this bug caused a small amount of hilarity in the codebase I refer to in the question (which to this day uses autocrlf=false), and led to many "EOL" commit messages and eventually to my writing a git pre-commit hook to check for/prevent introducing mixed line endings.

Update:

Note: As noted by VonC, starting from Git 2.8, merge markers will not introduce Unix-style line-endings to a Windows-style file.

Original:

One little hiccup that I've noticed with this setup is that when there are merge conflicts, the lines git adds to mark up the differences do not have Windows line-endings, even when the rest of the file does, and you can end up with a file with mixed line endings, e.g.:

// Some code<CR><LF>
<<<<<<< Updated upstream<LF>
// Change A<CR><LF>
=======<LF>
// Change B<CR><LF>
>>>>>>> Stashed changes<LF>
// More code<CR><LF>

This doesn't cause us any problems (I imagine any tool that can handle both types of line-endings will also deal sensible with mixed line-endings--certainly all the ones we use do), but it's something to be aware of.

The other thing* we've found, is that when using git diff to view changes to a file that has Windows line-endings, lines that have been added display their carriage returns, thus:

    // Not changed

+   // New line added in^M
+^M
    // Not changed
    // Not changed

* It doesn't really merit the term: "issue".

MySQLi prepared statements error reporting

Completeness

You need to check both $mysqli and $statement. If they are false, you need to output $mysqli->error or $statement->error respectively.

Efficiency

For simple scripts that may terminate, I use simple one-liners that trigger a PHP error with the message. For a more complex application, an error warning system should be activated instead, for example by throwing an exception.

Usage example 1: Simple script

# This is in a simple command line script
$mysqli = new mysqli('localhost', 'buzUser', 'buzPassword');
$q = "UPDATE foo SET bar=1";
($statement = $mysqli->prepare($q)) or trigger_error($mysqli->error, E_USER_ERROR);
$statement->execute() or trigger_error($statement->error, E_USER_ERROR);

Usage example 2: Application

# This is part of an application
class FuzDatabaseException extends Exception {
}

class Foo {
  public $mysqli;
  public function __construct(mysqli $mysqli) {
    $this->mysqli = $mysqli;
  }
  public function updateBar() {
    $q = "UPDATE foo SET bar=1";
    $statement = $this->mysqli->prepare($q);
    if (!$statement) {
      throw new FuzDatabaseException($mysqli->error);
    }

    if (!$statement->execute()) {
      throw new FuzDatabaseException($statement->error);
    }
  }
}

$foo = new Foo(new mysqli('localhost','buzUser','buzPassword'));
try {
  $foo->updateBar();
} catch (FuzDatabaseException $e)
  $msg = $e->getMessage();
  // Now send warning emails, write log
}

How to solve a timeout error in Laravel 5

Execution is not related to laravel go to the php.ini file In php.ini file set max_execution_time=360 (time may be variable depends on need) if you want to increase execution of a specific page then write ini_set('max_execution_time',360) at top of page

otherwise in htaccess php_value max_execution_time 360

HTML button to NOT submit form

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

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

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

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

figure of imshow() is too small

I'm new to python too. Here is something that looks like will do what you want to

axes([0.08, 0.08, 0.94-0.08, 0.94-0.08]) #[left, bottom, width, height]
axis('scaled')`

I believe this decides the size of the canvas.

String.contains in Java

Thinking of a string as a set of characters, in mathematics the empty set is always a subset of any set.

How to add title to subplots in Matplotlib?

ax.set_title() should set the titles for separate subplots:

import matplotlib.pyplot as plt

if __name__ == "__main__":
    data = [1, 2, 3, 4, 5]

    fig = plt.figure()
    fig.suptitle("Title for whole figure", fontsize=16)
    ax = plt.subplot("211")
    ax.set_title("Title for first plot")
    ax.plot(data)

    ax = plt.subplot("212")
    ax.set_title("Title for second plot")
    ax.plot(data)

    plt.show()

Can you check if this code works for you? Maybe something overwrites them later?

Check if a key exists inside a json object

I change your if statement slightly and works (also for inherited obj - look on snippet)

if(!("merchant_id" in thisSession)) alert("yeah");

_x000D_
_x000D_
var sessionA = {_x000D_
  amt: "10.00",_x000D_
  email: "[email protected]",_x000D_
  merchant_id: "sam",_x000D_
  mobileNo: "9874563210",_x000D_
  orderID: "123456",_x000D_
  passkey: "1234",_x000D_
}_x000D_
_x000D_
var sessionB = {_x000D_
  amt: "10.00",_x000D_
  email: "[email protected]",_x000D_
  mobileNo: "9874563210",_x000D_
  orderID: "123456",_x000D_
  passkey: "1234",_x000D_
}_x000D_
_x000D_
_x000D_
var sessionCfromA = Object.create(sessionA); // inheritance_x000D_
sessionCfromA.name = 'john';_x000D_
_x000D_
_x000D_
if (!("merchant_id" in sessionA)) alert("merchant_id not in sessionA");_x000D_
if (!("merchant_id" in sessionB)) alert("merchant_id not in sessionB");_x000D_
if (!("merchant_id" in sessionCfromA)) alert("merchant_id not in sessionCfromA");_x000D_
_x000D_
if ("merchant_id" in sessionA) alert("merchant_id in sessionA");_x000D_
if ("merchant_id" in sessionB) alert("merchant_id in sessionB");_x000D_
if ("merchant_id" in sessionCfromA) alert("merchant_id in sessionCfromA");
_x000D_
_x000D_
_x000D_

What's the opposite of 'make install', i.e. how do you uninstall a library in Linux?

I know of few packages that support "make uninstall" but many more that support make install DESTDIR=xxx" for staged installs.

You can use this to create a package which you install instead of installing directly from the source. I had no luck with checkinstall but fpm works very well.

This can also help you remove a package previously installed using make install. You simply force install your built package over the make installed one and then uninstall it.

For example, I used this recently to deal with protobuf-3.3.0. On RHEL7:

make install DESTDIR=dest
cd dest
fpm -f -s dir -t rpm -n protobuf -v 3.3.0 \
 --vendor "You Not RedHat" \
 --license "Google?" \
 --description "protocol buffers" \
 --rpm-dist el7 \
 -m [email protected] \
 --url "http:/somewhere/where/you/get/the/package/oritssource" \
 --rpm-autoreqprov \
 usr

 sudo rpm -i -f protobuf-3.3.0-1.el7.x86_64.rpm
 sudo rpm -e protobuf-3.3.0      

Prefer yum to rpm if you can.

On Debian9:

make install DESTDIR=dest
cd dest
fpm -f -s dir -t deb -n protobuf -v 3.3.0 \
-C `pwd` \
--prefix / \
--vendor "You Not Debian" \
--license "$(grep Copyright ../../LICENSE)" \
--description "$(cat README.adoc)" \
--deb-upstream-changelog ../../CHANGES.txt \
 --url "http:/somewhere/where/you/get/the/package/oritssource" \
 usr/local/bin \
 usr/local/lib \
 usr/local/include

 sudo apt install -f *.deb
 sudo apt-get remove protobuf

Prefer apt to dpkg where you can.

I've also posted answer this here

C# : "A first chance exception of type 'System.InvalidOperationException'"

If you check Thrown for Common Language Runtime Exception in the break when an exception window (Ctrl+Alt+E in Visual Studio), then the execution should break while you are debugging when the exception is thrown.

This will probably give you some insight into what is going on.

Example of the exceptions window

How to determine the first and last iteration in a foreach loop?

You can use an anonymous function, too:

$indexOfLastElement = count($array) - 1;
array_walk($array, function($element, $index) use ($indexOfLastElement) {
    // do something
    if (0 === $index) {
        // first element‘s treatment
    }
    if ($indexOfLastElement === $index) {
        // last not least
    }
});

Three more things should be mentioned:

  • If your array isn‘t indexed strictly (numerically) you must pipe your array through array_values first.
  • If you need to modify the $element you have to pass it by reference (&$element).
  • Any variables from outside the anonymous function you need inside, you‘ll have to list them next to $indexOfLastElement inside the use construct, again by reference if needed.

What is the right way to write my script 'src' url for a local development environment?

Write the src tag for calling the js file as

<script type='text/javascript' src='../Users/myUserName/Desktop/myPage.js'></script>

This should work.

Is there any method to get the URL without query string?

Here's an approach using the URL() interface:

new URL(location.pathname, location.href).href

Where is Python language used?

All the languages you've mentioned are Turing Complete, so in theory there is nothing one can do and another can't. In practice of course, there are differences, especially in productivity and efficiency. Compared to C, C++ and Java, which are static typed, Python is a dynamic language and can help you write the same code in significantly fewer lines. Python has a moto "batteries included", which means that the standard library offers all the things needed to build a complex application. Other languages would need external libraries for this. On top of this, since Python is an old and mature language (older than Java), many external libraries (for game development and scientific calculations just to mention a few) have been evolved. So Python can be used to program desktop applications and in fact in some cases more efficiently than other traditional languages.

Python is also a scripting language. This means that you can easily and quickly write scripts and simple tests with it.

More recently python is also used for web frameworks. Since there is a big code base and many python programmers, this was a logical thing to do. These web frameworks follow the practice mainly introduced by Ruby on Rails.

Concatenating bits in VHDL

Here is an example of concatenation operator:

architecture EXAMPLE of CONCATENATION is
   signal Z_BUS : bit_vector (3 downto 0);
   signal A_BIT, B_BIT, C_BIT, D_BIT : bit;
begin
   Z_BUS <= A_BIT & B_BIT & C_BIT & D_BIT;
end EXAMPLE;

FileNotFoundError: [Errno 2] No such file or directory

You are using a relative path, which means that the program looks for the file in the working directory. The error is telling you that there is no file of that name in the working directory.

Try using the exact, or absolute, path.

Git SSH error: "Connect to host: Bad file number"

After having this problem myself, I found a solution that works for me:

Error message:

    ssh -v [email protected]
    OpenSSH_5.8p1, OpenSSL 1.0.0d 8 Feb 2011
    debug1: Connecting to github.com [207.97.227.239] port 22.
    debug1: connect to address 207.97.227.239 port 22: Connection timed out
    ssh: connect to host github.com port 22: Connection timed out
    ssh: connect to host github.com port 22: Bad file number

You will only see the bad file number message when on windows using the MINGGW shell. Linux users will just get Timed out.

Problem:

SSH is probably blocked on port 22. You can see this by typing

    $nmap -sS github.com -p 22
    Starting Nmap 5.35DC1 ( http://nmap.org ) at 2011-11-05 10:53 CET
    Nmap scan report for github.com (207.97.227.239)
    Host is up (0.10s latency).
    PORT   STATE    SERVICE
    22/tcp ***filtered*** ssh

    Nmap done: 1 IP address (1 host up) scanned in 2.63 seconds

As you can see the state is Filtered, which means something is blocking it. You can solve this by performing an SSH to port 443 (your firewall / isp will not block this). It is also important that you need to ssh to "ssh.github.com" instead of github.com. Otherwise, you will report to the webserver instead of the ssh server. Below are all the steps needed to solve this problem.

Solution:

(First of all make sure you generated your keys like explained on http://help.github.com/win-set-up-git/)

create file ~/.ssh/config (ssh config file located in your user directory. On windows probably %USERPROFILE%\.ssh\config

Paste the following code in it:

    Host github.com
    User git
    Hostname ssh.github.com
    PreferredAuthentications publickey
    IdentityFile ~/.ssh/id_rsa
    Port 443

Save the file.

Perform ssh like usual:

$ssh -T github.com 
    $Enter passphrase for key '.......... (you can smile now :))

Note that I do not have to supply the username or port number.

Android Crop Center of Bitmap

public static Bitmap resizeAndCropCenter(Bitmap bitmap, int size, boolean recycle) {
    int w = bitmap.getWidth();
    int h = bitmap.getHeight();
    if (w == size && h == size) return bitmap;
    // scale the image so that the shorter side equals to the target;
    // the longer side will be center-cropped.
    float scale = (float) size / Math.min(w,  h);
    Bitmap target = Bitmap.createBitmap(size, size, getConfig(bitmap));
    int width = Math.round(scale * bitmap.getWidth());
    int height = Math.round(scale * bitmap.getHeight());
    Canvas canvas = new Canvas(target);
    canvas.translate((size - width) / 2f, (size - height) / 2f);
    canvas.scale(scale, scale);
    Paint paint = new Paint(Paint.FILTER_BITMAP_FLAG | Paint.DITHER_FLAG);
    canvas.drawBitmap(bitmap, 0, 0, paint);
    if (recycle) bitmap.recycle();
    return target;
}

private static Bitmap.Config getConfig(Bitmap bitmap) {
    Bitmap.Config config = bitmap.getConfig();
    if (config == null) {
        config = Bitmap.Config.ARGB_8888;
    }
    return config;
}

Android: how to draw a border to a LinearLayout

Extend LinearLayout/RelativeLayout and use it straight on the XML

package com.pkg_name ;
...imports...
public class LinearLayoutOutlined extends LinearLayout {
    Paint paint;    

    public LinearLayoutOutlined(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
        setWillNotDraw(false) ;
        paint = new Paint();
    }
    public LinearLayoutOutlined(Context context, AttributeSet attrs) {
        super(context, attrs);
        // TODO Auto-generated constructor stub
        setWillNotDraw(false) ;
        paint = new Paint();
    }
    @Override
    protected void onDraw(Canvas canvas) {
        /*
        Paint fillPaint = paint;
        fillPaint.setARGB(255, 0, 255, 0);
        fillPaint.setStyle(Paint.Style.FILL);
        canvas.drawPaint(fillPaint) ;
        */

        Paint strokePaint = paint;
        strokePaint.setARGB(255, 255, 0, 0);
        strokePaint.setStyle(Paint.Style.STROKE);
        strokePaint.setStrokeWidth(2);  
        Rect r = canvas.getClipBounds() ;
        Rect outline = new Rect( 1,1,r.right-1, r.bottom-1) ;
        canvas.drawRect(outline, strokePaint) ;
    }

}

<?xml version="1.0" encoding="utf-8"?>

<com.pkg_name.LinearLayoutOutlined
   xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="vertical"
    android:layout_width=...
    android:layout_height=...
   >
   ... your widgets here ...

</com.pkg_name.LinearLayoutOutlined>

Before and After Suite execution hook in jUnit 4.x

As far as I know there is no mechanism for doing this in JUnit, however you could try subclassing Suite and overriding the run() method with a version that does provide hooks.

<script> tag vs <script type = 'text/javascript'> tag

You only need <script></script> Tag that's it. <script type="text/javascript"></script> is not a valid HTML tag, so for best SEO practice use <script></script>

ReactJS - How to use comments?

_x000D_
_x000D_
{/*_x000D_
   <Header />_x000D_
   <Content />_x000D_
   <MapList />_x000D_
   <HelloWorld />_x000D_
*/}
_x000D_
_x000D_
_x000D_

Table header to stay fixed at the top when user scrolls it out of view with jQuery

I wrote a plugin that does this. Ive been working on it for about a year now and I think it handles all the corner cases pretty well:

  • scrolling within a container with overflow
  • scrolling within a window
  • taking care of what happens when you resize the window
  • keeping your events bound to the header
  • most importantly it doesn't force you to change your table's css to make it work

Here are some demos/docs:
http://mkoryak.github.io/floatThead/

Java 8 Lambda function that throws exception?

If you have lombok, you can annotate your method with @SneakyThrows

SneakyThrow does not silently swallow, wrap into RuntimeException, or otherwise modify any exceptions of the listed checked exception types. The JVM does not check for the consistency of the checked exception system; javac does, and this annotation lets you opt out of its mechanism.

https://projectlombok.org/features/SneakyThrows

Returning binary file from controller in ASP.NET Web API

The overload that you're using sets the enumeration of serialization formatters. You need to specify the content type explicitly like:

httpResponseMessage.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");

What is the "hasClass" function with plain JavaScript?

Element.matches()

Instead of $(element).hasClass('example') in jQuery, you can use element.matches('.example') in plain JavaScript:

if (element.matches('.example')) {
  // Element has example class ...
}

View Browser Compatibility

OnItemClickListener using ArrayAdapter for ListView

i'm using arrayadpter ,using this follwed code i'm able to get items

String value = (String)adapter.getItemAtPosition(position);

listView.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
             String string=adapter.getItem(position);
             Log.d("**********", string);

        }
    });

Need a query that returns every field that contains a specified letter

I'll assume you meant more or less what you said, and you want to find keywords in your table that "contain the letter 'a' and the letter 'b'." Some of the solutions here give the answer to a different question.

To get keywords that contain both the letters 'a' and 'b' in them (as opposed to those that contain either letter), you can use 'ab' as the in the query below:

select
  keyword
from myTable
where not exists (
  select Nums26.i from Nums26
  where Nums26.i <= len(<matchsetstring>) -- or your dialect's equivalent for LEN()
  and keyword not like '%'+substring(<matchsetstring>,Nums26.i,1)+'%' -- adapt SUBSTRING to your dialect
);

The table named "Nums26" should contain a column "i" (indexed for efficiency) that contains each of the values 1 through 26 (or more if you might try to match more than letters). See below. Advice given by others applies with regard to upper/lower case. If your collation is case-sensitive, however, you can't simply specify 'aAbB' here as your , because that would request keywords that contain each of the four characters a, A, b, and B. You might use UPPER and match 'AB', perhaps.

create table nums26 (
  i int primary key
);
insert into nums26 values (1);
insert into nums26 select 1+i from nums26;
insert into nums26 select 2+i from nums26;
insert into nums26 select 4+i from nums26;
insert into nums26 select 8+i from nums26;
insert into nums26 select 16+i from nums26;

Difference between datetime and timestamp in sqlserver?

Datetime is a datatype.

Timestamp is a method for row versioning. In fact, in sql server 2008 this column type was renamed (i.e. timestamp is deprecated) to rowversion. It basically means that every time a row is changed, this value is increased. This is done with a database counter which automatically increase for every inserted or updated row.

For more information:

http://www.sqlteam.com/article/timestamps-vs-datetime-data-types

http://msdn.microsoft.com/en-us/library/ms182776.aspx

How to change XML Attribute

Using LINQ to xml if you are using framework 3.5:

using System.Xml.Linq;

XDocument xmlFile = XDocument.Load("books.xml"); 

var query = from c in xmlFile.Elements("catalog").Elements("book")    
            select c; 

foreach (XElement book in query) 
{
   book.Attribute("attr1").Value = "MyNewValue";
}

xmlFile.Save("books.xml");

How to disable compiler optimizations in gcc?

For gcc you want to omit any -O1 -O2 or -O3 options passed to the compiler or if you already have them you can append the -O0 option to turn it off again. It might also help you to add -g for debug so that you can see the c source and disassembled machine code in your debugger.

See also: http://sourceware.org/gdb/onlinedocs/gdb/Optimized-Code.html

How to disable a input in angular2

I think I figured out the problem, this input field is part of a reactive form (?), since you have included formControlName. This means that what you are trying to do by disabling the input field with is_edit is not working, e.g your attempt [disabled]="is_edit", which would in other cases work. With your form you need to do something like this:

toggle() {
  let control = this.myForm.get('name')
  control.disabled ? control.enable() : control.disable();
}

and lose the is_edit altogether.

if you want the input field to be disabled as default, you need to set the form control as:

name: [{value: '', disabled:true}]

Here's a plunker

How to stop a function

In this example, the line do_something_else() will not be executed if do_not_continue is True. Control will return, instead, to whichever function called some_function.

def some_function():
    if do_not_continue:
        return  # implicitly, this is the same as saying `return None` 
    do_something_else()

How do I install Maven with Yum?

For those of you that are looking for a way to install Maven in 2018:

$ sudo yum install maven

is supported these days.

Javascript variable access in HTML

<html>
<head>
<script>
    function putText() {
        var simpleText = "hello_world";
        var finalSplitText = simpleText.split("_");
        var splitText = finalSplitText[0];
        document.getElementById("destination").innerHTML = "I need the value of " + splitText + " variable here";
    }
</script>
</head>
<body onLoad = putText()>
    <a id="destination" href = test.html>I need the value of "splitText" variable here</a>
</body>
</html>

How to send data to COM PORT using JAVA?

The Java Communications API (also known as javax.comm) provides applications access to RS-232 hardware (serial ports): http://www.oracle.com/technetwork/java/index-jsp-141752.html

Can regular JavaScript be mixed with jQuery?

You can, but be aware of the return types with jQuery functions. jQuery won't always use the exact same JavaScript object type, although generally they will return subclasses of what you would expect to be returned from a similar JavaScript function.

Reading a plain text file in Java

This code I programmed is much faster for very large files:

public String readDoc(File f) {
    String text = "";
    int read, N = 1024 * 1024;
    char[] buffer = new char[N];

    try {
        FileReader fr = new FileReader(f);
        BufferedReader br = new BufferedReader(fr);

        while(true) {
            read = br.read(buffer, 0, N);
            text += new String(buffer, 0, read);

            if(read < N) {
                break;
            }
        }
    } catch(Exception ex) {
        ex.printStackTrace();
    }

    return text;
}

How long is the SHA256 hash?

It will be fixed 64 chars, so use char(64)

Upgrade python in a virtualenv

Step 1: Freeze requirement & take a back-up of existing env

pip freeze > requirements.txt
deactivate
mv env env_old

Step 2: Install Python 3.7 & activate virutal environment

sudo apt-get install python3.7-venv
python3.7 -m venv env
source env/bin/activate
python --version

Step 3: Install requirements

sudo apt-get install python3.7-dev
pip3 install -r requirements.txt

How to declare a variable in MySQL?

Use set or select

SET @counter := 100;
SELECT @variable_name := value;

example :

SELECT @price := MAX(product.price)
FROM product 

MVC 4 client side validation not working

In my case the validation itself was working (I could validate an element and retrieve a correct boolean value), but there was no visual output.

My fault was that I forgot this line @Html.ValidationMessageFor(m => ...)

The TS has this in his code and got me on the right track, but I put it in here as reference for others.

Migrating from VMWARE to VirtualBox

This error occurs because VMware has a bug that uses the absolute path of the disk file in certain situations.

If you look at the top of that small *.vmdk file you'll likely see an incorrect absolute path to the original VMDK file that needs to be corrected.

Cannot perform runtime binding on a null reference, But it is NOT a null reference

This error happens when you have a ViewBag Non-Existent in your razor code calling a method.

Controller

public ActionResult Accept(int id)
{
    return View();
}

razor:

<div class="form-group">
      @Html.LabelFor(model => model.ToId, "To", htmlAttributes: new { @class = "control-label col-md-2" })
     <div class="col-md-10">
           @Html.Flag(Model.from)
     </div>
</div>
<div class="form-group">
     <div class="col-md-10">
          <input value="@ViewBag.MaximounAmount.ToString()" />@* HERE is the error *@ 
     </div>
</div>

For some reason, the .net aren't able to show the error in the correct line.

Normally this causes a lot of wasted time.

Adding a column to an existing table in a Rails migration

If you have already run your original migration (before editing it), then you need to generate a new migration (rails generate migration add_email_to_users email:string will do the trick). It will create a migration file containing line: add_column :users, email, string Then do a rake db:migrate and it'll run the new migration, creating the new column.

If you have not yet run the original migration you can just edit it, like you're trying to do. Your migration code is almost perfect: you just need to remove the add_column line completely (that code is trying to add a column to a table, before the table has been created, and your table creation code has already been updated to include a t.string :email anyway).

How to prevent "The play() request was interrupted by a call to pause()" error?

I think they updated the html5 video and deprecated some codecs. It worked for me after removing the codecs.

In the below example:

_x000D_
_x000D_
<video>_x000D_
    <source src="sample-clip.mp4" type="video/mp4; codecs='avc1.42E01E, mp4a.40.2'">_x000D_
    <source src="sample-clip.webm" type="video/webm; codecs='vp8, vorbis'"> _x000D_
</video>_x000D_
_x000D_
    must be changed to_x000D_
_x000D_
<video>_x000D_
    <source src="sample-clip.mp4" type="video/mp4">_x000D_
    <source src="sample-clip.webm" type="video/webm">_x000D_
</video>
_x000D_
_x000D_
_x000D_

Graphviz's executables are not found (Python 3.4)

I'm using Windows 10, Python 3.6 on Anaconda 3 and have faced the same issue.

I've had it work by doing the following in sequence:

  1. From Anaconda Terminal: pip install pydotplus
  2. From Anaconda Terminal: conda install pydotplus
  3. From Anaconda Terminal: pip install graphviz
  4. From Anaconda Terminal: conda install graphviz
  5. Went to Windows Environment Varialbes, PATH, and added the location of my dot.exe file under graphviz directory in Anaconda.

worked fine after that.

AngularJS toggle class using ng-class

I made this work in this way:

<button class="btn" ng-click='toggleClass($event)'>button one</button>
<button class="btn" ng-click='toggleClass($event)'>button two</button>

in your controller:

$scope.toggleClass = function (event) {
    $(event.target).toggleClass('active');
}

Declare and initialize a Dictionary in Typescript

Typescript fails in your case because it expects all the fields to be present. Use Record and Partial utility types to solve it.

Record<string, Partial<IPerson>>

interface IPerson {
   firstName: string;
   lastName: string;
}

var persons: Record<string, Partial<IPerson>> = {
   "p1": { firstName: "F1", lastName: "L1" },
   "p2": { firstName: "F2" }
};

Explanation.

  1. Record type creates a dictionary/hashmap.
  2. Partial type says some of the fields may be missing.

Alternate.

If you wish to make last name optional you can append a ? Typescript will know that it's optional.

lastName?: string;

https://www.typescriptlang.org/docs/handbook/utility-types.html

Generating a UUID in Postgres for Insert statement?

The answer by Craig Ringer is correct. Here's a little more info for Postgres 9.1 and later…

Is Extension Available?

You can only install an extension if it has already been built for your Postgres installation (your cluster in Postgres lingo). For example, I found the uuid-ossp extension included as part of the installer for Mac OS X kindly provided by EnterpriseDB.com. Any of a few dozen extensions may be available.

To see if the uuid-ossp extension is available in your Postgres cluster, run this SQL to query the pg_available_extensions system catalog:

SELECT * FROM pg_available_extensions;

Install Extension

To install that UUID-related extension, use the CREATE EXTENSION command as seen in this this SQL:

CREATE EXTENSION IF NOT EXISTS "uuid-ossp";

Beware: I found the QUOTATION MARK characters around extension name to be required, despite documentation to the contrary.

The SQL standards committee or Postgres team chose an odd name for that command. To my mind, they should have chosen something like "INSTALL EXTENSION" or "USE EXTENSION".

Verify Installation

You can verify the extension was successfully installed in the desired database by running this SQL to query the pg_extension system catalog:

SELECT * FROM pg_extension;

UUID as default value

For more info, see the Question: Default value for UUID column in Postgres

The Old Way

The information above uses the new Extensions feature added to Postgres 9.1. In previous versions, we had to find and run a script in a .sql file. The Extensions feature was added to make installation easier, trading a bit more work for the creator of an extension for less work on the part of the user/consumer of the extension. See my blog post for more discussion.

Types of UUIDs

By the way, the code in the Question calls the function uuid_generate_v4(). This generates a type known as Version 4 where nearly all of the 128 bits are randomly generated. While this is fine for limited use on smaller set of rows, if you want to virtually eliminate any possibility of collision, use another "version" of UUID.

For example, the original Version 1 combines the MAC address of the host computer with the current date-time and an arbitrary number, the chance of collisions is practically nil.

For more discussion, see my Answer on related Question.

Eliminate space before \begin{itemize}

\renewcommand{\@listI}{%
\leftmargin=25pt
\rightmargin=0pt
\labelsep=5pt
\labelwidth=20pt
\itemindent=0pt
\listparindent=0pt
\topsep=0pt plus 2pt minus 4pt
\partopsep=0pt plus 1pt minus 1pt
\parsep=0pt plus 1pt
\itemsep=\parsep}

Soft Edges using CSS?

It depends on what type of fading you are looking for.

But with shadow and rounded corners you can get a nice result. Rounded corners because the bigger the shadow, the weirder it will look in the edges unless you balance it out with rounded corners.

http://jsfiddle.net/tLu7u/

also.. http://css3pie.com/

Injecting $scope into an angular service function()

Instead of trying to modify the $scope within the service, you can implement a $watch within your controller to watch a property on your service for changes and then update a property on the $scope. Here is an example you might try in a controller:

angular.module('cfd')
    .controller('MyController', ['$scope', 'StudentService', function ($scope, StudentService) {

        $scope.students = null;

        (function () {
            $scope.$watch(function () {
                return StudentService.students;
            }, function (newVal, oldVal) {
                if ( newValue !== oldValue ) {
                    $scope.students = newVal;
                }
            });
        }());
    }]);

One thing to note is that within your service, in order for the students property to be visible, it needs to be on the Service object or this like so:

this.students = $http.get(path).then(function (resp) {
  return resp.data;
});

Random number generator only generating one random number

Always get a positive random number.

 var nexnumber = Guid.NewGuid().GetHashCode();
        if (nexnumber < 0)
        {
            nexnumber *= -1;
        }

indexOf method in an object array?

I will prefer to use findIndex() method:

 var index = myArray.findIndex('hello','stevie');

index will give you the index number.

How to manually reload Google Map with JavaScript

Yes, you can 'refresh' a Google Map like this:

google.maps.event.trigger(map, 'resize');

This basically sends a signal to your map to redraw it.

Hope that helps!

How to deal with floating point number precision in JavaScript?

You can't represent most decimal fractions exactly with binary floating point types (which is what ECMAScript uses to represent floating point values). So there isn't an elegant solution unless you use arbitrary precision arithmetic types or a decimal based floating point type. For example, the Calculator app that ships with Windows now uses arbitrary precision arithmetic to solve this problem.

Disable color change of anchor tag when visited

You can't. You can only style the visited state.

For other people who find this, make sure that you have them in the right order:

a {color:#FF0000;}         /* Unvisited link  */
a:visited {color:#00FF00;} /* Visited link    */
a:hover {color:#FF00FF;}   /* Mouse over link */
a:active {color:#0000FF;}  /* Selected link   */

How to use mysql JOIN without ON condition?

There are several ways to do a cross join or cartesian product:

SELECT column_names FROM table1 CROSS JOIN table2;

SELECT column_names FROM table1, table2;

SELECT column_names FROM table1 JOIN table2;

Neglecting the on condition in the third case is what results in a cross join.

Comparing Class Types in Java

Check Class.java source code for equals()

public boolean equals(Object obj) {
  return this == obj;
}

Getting the first and last day of a month, using a given DateTime object

Here you can add one month for the first day of current month than delete 1 day from that day.

DateTime now = DateTime.Now;
var startDate = new DateTime(now.Year, now.Month, 1);
var endDate = startDate.AddMonths(1).AddDays(-1);

How to get input text length and validate user in javascript

JavaScript validation is not secure as anybody can change what your script does in the browser. Using it for enhancing the visual experience is ok though.

var textBox = document.getElementById("myTextBox");
var textLength = textBox.value.length;
if(textLength > 5)
{
    //red
    textBox.style.backgroundColor = "#FF0000";
}
else
{
    //green
    textBox.style.backgroundColor = "#00FF00";
}

Setting a PHP $_SESSION['var'] using jQuery

Whats you are looking for is jQuery Ajax. And then just setup a php page to process the request.

ASP.NET Core Get Json Array using IConfiguration

Add a level in your appsettings.json :

{
  "MySettings": {
    "MyArray": [
      "str1",
      "str2",
      "str3"
    ]
  }
}

Create a class representing your section :

public class MySettings
{
     public List<string> MyArray {get; set;}
}

In your application startup class, bind your model an inject it in the DI service :

services.Configure<MySettings>(options => Configuration.GetSection("MySettings").Bind(options));

And in your controller, get your configuration data from the DI service :

public class HomeController : Controller
{
    private readonly List<string> _myArray;

    public HomeController(IOptions<MySettings> mySettings)
    {
        _myArray = mySettings.Value.MyArray;
    }

    public IActionResult Index()
    {
        return Json(_myArray);
    }
}

You can also store your entire configuration model in a property in your controller, if you need all the data :

public class HomeController : Controller
{
    private readonly MySettings _mySettings;

    public HomeController(IOptions<MySettings> mySettings)
    {
        _mySettings = mySettings.Value;
    }

    public IActionResult Index()
    {
        return Json(_mySettings.MyArray);
    }
}

The ASP.NET Core's dependency injection service works just like a charm :)

gnuplot plotting multiple line graphs

I think your problem is your version numbers. Try making 8.1 --> 8.01, and so forth. That should put the points in the right order.

Alternatively, you could plot using X, where X is the column number you want, instead of using 1:X. That will plot those values on the y axis and integers on the x axis. Try:

plot "ls.dat" using 2 title 'Removed' with lines, \
     "ls.dat" using 3 title 'Added' with lines, \
     "ls.dat" using 4 title 'Modified' with lines

How do I compile jrxml to get jasper?

In eclipse,

  • Install Jaspersoft Studio for eclipse.
  • Right click the .jrxml file and select Open with JasperReports Book Editor
  • Open the Design tab for the .jrxml file.
  • On top of the window you can see the Compile Report icon.

How can I generate an INSERT script for an existing SQL Server table that includes all stored rows?

Just to share, I've developed my own script to do it. Feel free to use it. It generates "SELECT" statements that you can then run on the tables to generate the "INSERT" statements.

select distinct 'SELECT ''INSERT INTO ' + schema_name(ta.schema_id) + '.' + so.name + ' (' + substring(o.list, 1, len(o.list)-1) + ') VALUES ('
+ substring(val.list, 1, len(val.list)-1) + ');''  FROM ' + schema_name(ta.schema_id) + '.' + so.name + ';'
from    sys.objects so
join sys.tables ta on ta.object_id=so.object_id
cross apply
(SELECT '  ' +column_name + ', '
 from information_schema.columns c
 join syscolumns co on co.name=c.COLUMN_NAME and object_name(co.id)=so.name and OBJECT_NAME(co.id)=c.TABLE_NAME and co.id=so.object_id and c.TABLE_SCHEMA=SCHEMA_NAME(so.schema_id)
 where table_name = so.name
 order by ordinal_position
FOR XML PATH('')) o (list)
cross apply
(SELECT '''+' +case
         when data_type = 'uniqueidentifier' THEN 'CASE WHEN [' + column_name+'] IS NULL THEN ''NULL'' ELSE ''''''''+CONVERT(NVARCHAR(MAX),[' + COLUMN_NAME + '])+'''''''' END '
         WHEN data_type = 'timestamp' then '''''''''+CONVERT(NVARCHAR(MAX),CONVERT(BINARY(8),[' + COLUMN_NAME + ']),1)+'''''''''
         WHEN data_type = 'nvarchar' then 'CASE WHEN [' + column_name+'] IS NULL THEN ''NULL'' ELSE ''''''''+REPLACE([' + COLUMN_NAME + '],'''''''','''''''''''')+'''''''' END'
         WHEN data_type = 'varchar' then 'CASE WHEN [' + column_name+'] IS NULL THEN ''NULL'' ELSE ''''''''+REPLACE([' + COLUMN_NAME + '],'''''''','''''''''''')+'''''''' END'
         WHEN data_type = 'char' then 'CASE WHEN [' + column_name+'] IS NULL THEN ''NULL'' ELSE ''''''''+REPLACE([' + COLUMN_NAME + '],'''''''','''''''''''')+'''''''' END'
         WHEN data_type = 'nchar' then 'CASE WHEN [' + column_name+'] IS NULL THEN ''NULL'' ELSE ''''''''+REPLACE([' + COLUMN_NAME + '],'''''''','''''''''''')+'''''''' END'
         when DATA_TYPE='datetime' then 'CASE WHEN [' + column_name+'] IS NULL THEN ''NULL'' ELSE ''''''''+CONVERT(NVARCHAR(MAX),[' + COLUMN_NAME + '],121)+'''''''' END '
         when DATA_TYPE='datetime2' then 'CASE WHEN [' + column_name+'] IS NULL THEN ''NULL'' ELSE ''''''''+CONVERT(NVARCHAR(MAX),[' + COLUMN_NAME + '],121)+'''''''' END '
         when DATA_TYPE='geography' and column_name<>'Shape' then 'ST_GeomFromText(''POINT('+column_name+'.Lat '+column_name+'.Long)'') '
         when DATA_TYPE='geography' and column_name='Shape' then '''''''''+CONVERT(NVARCHAR(MAX),[' + COLUMN_NAME + '])+'''''''''
         when DATA_TYPE='bit' then '''''''''+CONVERT(NVARCHAR(MAX),[' + COLUMN_NAME + '])+'''''''''
         when DATA_TYPE='xml' then 'CASE WHEN [' + column_name+'] IS NULL THEN ''NULL'' ELSE ''''''''+REPLACE(CONVERT(NVARCHAR(MAX),[' + COLUMN_NAME + ']),'''''''','''''''''''')+'''''''' END '
         WHEN DATA_TYPE='image' then 'CASE WHEN [' + column_name+'] IS NULL THEN ''NULL'' ELSE ''''''''+CONVERT(NVARCHAR(MAX),CONVERT(VARBINARY(MAX),[' + COLUMN_NAME + ']),1)+'''''''' END '
         WHEN DATA_TYPE='varbinary' then 'CASE WHEN [' + column_name+'] IS NULL THEN ''NULL'' ELSE ''''''''+CONVERT(NVARCHAR(MAX),[' + COLUMN_NAME + '],1)+'''''''' END '
         WHEN DATA_TYPE='binary' then 'CASE WHEN [' + column_name+'] IS NULL THEN ''NULL'' ELSE ''''''''+CONVERT(NVARCHAR(MAX),[' + COLUMN_NAME + '],1)+'''''''' END '
         when DATA_TYPE='time' then 'CASE WHEN [' + column_name+'] IS NULL THEN ''NULL'' ELSE ''''''''+CONVERT(NVARCHAR(MAX),[' + COLUMN_NAME + '])+'''''''' END '
         ELSE 'CASE WHEN [' + column_name+'] IS NULL THEN ''NULL'' ELSE CONVERT(NVARCHAR(MAX),['+column_name+']) END' end
   + '+'', '
 from information_schema.columns c
 join syscolumns co on co.name=c.COLUMN_NAME and object_name(co.id)=so.name and OBJECT_NAME(co.id)=c.TABLE_NAME and co.id=so.object_id and c.TABLE_SCHEMA=SCHEMA_NAME(so.schema_id)
 where table_name = so.name
 order by ordinal_position
FOR XML PATH('')) val (list)
where   so.type = 'U'

How to overwrite existing files in batch?

If destination file is read only use /y/r

xcopy /y/r source.txt dest.txt

Git command to display HEAD commit id?

Use the command:

git rev-parse HEAD

For the short version:

git rev-parse --short HEAD

denied: requested access to the resource is denied : docker

It worked after I changed the "docker login https://hub.docker.com" to "docker login docker.io" and provided username & password.

Then follow below commands:

docker tag local-image:tagname new-repo:tagname

docker push new-repo:tagname

NOTE: "new-repo" will contain "Docker ID + Repo name"

Here I have created "ubuntu" repo in the Docker Hub before running below command.

Example:

docker tag alok/ubuntu:latest aloktiwari2007/ubuntu:latest

docker push aloktiwari2007/ubuntu:latest

When does Java's Thread.sleep throw InterruptedException?

Methods like sleep() and wait() of class Thread might throw an InterruptedException. This will happen if some other thread wanted to interrupt the thread that is waiting or sleeping.

Generate list of all possible permutations of a string

... and here is the C version:

void permute(const char *s, char *out, int *used, int len, int lev)
{
    if (len == lev) {
        out[lev] = '\0';
        puts(out);
        return;
    }

    int i;
    for (i = 0; i < len; ++i) {
        if (! used[i])
            continue;

        used[i] = 1;
        out[lev] = s[i];
        permute(s, out, used, len, lev + 1);
        used[i] = 0;
    }
    return;
}

Error :Request header field Content-Type is not allowed by Access-Control-Allow-Headers

Had the same problem, while differently from other answers in my case I use ASP.NET to develop the WebAPI server.

I already had Corps allowed and it worked for GET requests. To make POST requests work I needed to add 'AllowAnyHeader()' and 'AllowAnyMethod()' options to the list of Corp options.

Here are essential parts of related functions in Start class look like:

ConfigureServices method:

    services.AddCors(options =>
    {
        options.AddPolicy(name: MyAllowSpecificOrigins,
                          builder =>
                          {
                              builder
                                  .WithOrigins("http://localhost:4200")
                                  .AllowAnyHeader()
                                  .AllowAnyMethod()
                                  //.AllowCredentials()
                                  ;
                          });
    });

Configure method:

        app.UseCors(MyAllowSpecificOrigins);

Found this from:

Global Angular CLI version greater than local version

To answer one of the questions, it is necessary to have both a global and local install for the tools to work.

If you try to run ng serve on an application without the local install of the CLI (global install only), you will get the following error.

You have to be inside an Angular CLI project in order to use the serve command.

It will also print this message:

Please take the following steps to avoid issues:
"npm install --save-dev @angular/cli@latest"

Run that npm command to update the CLI locally, and avoid the warning that you are getting.

Other question: It looks like they do not have to be in sync, but it's probably best that they are in order to avoid any unusual behavior with the tool, or any inconsistencies with the code the tool generates.

Why do we need both the global install, and a local install?

The global install is needed to start a new application. The ng new <app-name> command is run using the global installation of the CLI. In fact, if you try to run ng new while inside the folder structure of an existing CLI application, you get this lovely error:

You cannot use the new command inside an Angular CLI project.

Other commands that can be run from the global install are ng help, ng get/set with the --global option, ng version, ng doc, and ng completion.

The local install of the CLI is used after an application has been built. This way, when new versions of the CLI are available, you can update your global install, and not affect the local install. This is good for the stability of a project. Most ng commands only make sense with the local version, like lint, build and serve, etc.

According to the CLI GitHub readme, to update the CLI you must update the global and local package. However, I have used the CLI where the global and local version vary without any trouble so far. If I ever run across an error related to having the global and local CLI versions out of sync, I will post that here.

Delete duplicate records from a SQL table without a primary key

delete sub from (select ROW_NUMBER() OVer(Partition by empid order by empid)cnt from employee)sub where sub.cnt>1

Datanode process not running in Hadoop

Follow these steps and your datanode will start again.

  1. Stop dfs.
  2. Open hdfs-site.xml
  3. Remove the data.dir and name.dir properties from hdfs-site.xml and -format namenode again.
  4. Then remove the hadoopdata directory and add the data.dir and name.dir in hdfs-site.xml and again format namenode.
  5. Then start dfs again.

PHP code to get selected text of a combo box

you can make a jQuery onChange event to get the text from the combobox when the user select one of them:

<script>    
     $( "select" )
     .change(function () {
     var str = "";
     $( "select option:selected" ).each(function() {
     str += $( this ).text() + " ";
     });
     $('#EvaluationName').val(str);
     })
     .change();
 </script>

When you select an option, it will save the text in an Input hidde

  <input type="hidden" id="EvaluationName" name="EvaluationName" value="<?= $Evaluation ?>" />

After that, when you submit the form, just catch up the value of the input

$Evaluation = $_REQUEST['EvaluationName'];

Then you can do wathever you want with the text, for instance save it in a session variable and send it to other page. etc.

Angular - How to apply [ngStyle] conditions

You can use an inline if inside your ngStyle:

[ngStyle]="styleOne?{'background-color': 'red'} : {'background-color': 'blue'}"

A batter way in my opinion is to store your background color inside a variable and then set the background-color as the variable value:

[style.background-color]="myColorVaraible"

Visual Studio Code Search and Replace with Regular Expressions

So, your goal is to search and replace?
According to the Official Visual Studio's keyboard shotcuts pdf, you can press Ctrl + H on Windows and Linux, or ??F on Mac to enable search and replace tool:

Visual studio code's search & replace tab If you mean to disable the code, you just have to put <h1> in search, and replace to ####.

But if you want to use this regex instead, you may enable it in the icon: .* and use the regex: <h1>(.+?)<\/h1> and replace to: #### $1.

And as @tpartee suggested, here is some more information about Visual Studio's engine if you would like to learn more:

Why isn't Python very good for functional programming?

Another reason not mentioned above is that many built-in functions and methods of built-in types modify an object but do not return the modified object. If those modified objects were returned, that would make functional code cleaner and more concise. For example, if some_list.append(some_object) returned some_list with some_object appended.

How do I get the Session Object in Spring?

I try with next code and work excellent

    import org.springframework.security.core.Authentication;
    import org.springframework.security.core.context.SecurityContextHolder;
    import org.springframework.stereotype.Controller;
    import org.springframework.ui.ModelMap;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;

    /**
     * Created by jaime on 14/01/15.
     */

    @Controller
    public class obteinUserSession {
        @RequestMapping(value = "/loginds", method = RequestMethod.GET)
        public String UserSession(ModelMap modelMap) {
            Authentication auth = SecurityContextHolder.getContext().getAuthentication();
            String name = auth.getName();
            modelMap.addAttribute("username", name);
            return "hellos " + name;
        }

How to pass List from Controller to View in MVC 3

You can use the dynamic object ViewBag to pass data from Controllers to Views.

Add the following to your controller:

ViewBag.MyList = myList;

Then you can acces it from your view:

@ViewBag.MyList

// e.g.
@foreach (var item in ViewBag.MyList) { ... }

How do I close a tkinter window?

Try this:

from Tkinter import *
import sys
def exitApp():
    sys.exit()
root = Tk()
Button(root, text="Quit", command=exitApp).pack()
root.mainloop()

Angular 2 - Setting selected value on dropdown list

I would like to add, [ngValue]="..." support strings, but you need to add simple quotes if it represents a number, like [ngValue]="'...'". It was to complement the Günter Zöchbauer answer.

How to track untracked content?

This question has been answered already, but thought I'd add to the mix what I found out when I got these messages.

I have a repo called playground that contains a number of sandbox apps. I added two new apps from a tutorial to the playground directory by cloning the tutorial's repo. The result was that the new apps' git stuff pointed to the tutorial's repo and not to my repo. The solution was to delete the .git directory from each of those apps' directories, mv the apps' directories outside the playground directory, and then mv them back and run git add .. After that it worked.

NTFS performance and large volumes of files and directories

100,000 should be fine.

I have (anecdotally) seen people having problems with many millions of files and I have had problems myself with Explorer just not having a clue how to count past 60-something thousand files, but NTFS should be good for the volumes you're talking.

In case you're wondering, the technical (and I hope theoretical) maximum number of files is: 4,294,967,295

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

If you ought to spare memory, read char by char and realloc each time. Performance will die, but you'll spare this 10 bytes.

Another good tradeoff is to read in a function (using a local variable) then copying. So the big buffer will be function scoped.

How to generate and manually insert a uniqueidentifier in sql server?

ApplicationId must be of type UniqueIdentifier. Your code works fine if you do:

DECLARE @TTEST TABLE
(
  TEST UNIQUEIDENTIFIER
)

DECLARE @UNIQUEX UNIQUEIDENTIFIER
SET @UNIQUEX = NEWID();

INSERT INTO @TTEST
(TEST)
VALUES
(@UNIQUEX);

SELECT * FROM @TTEST

Therefore I would say it is safe to assume that ApplicationId is not the correct data type.

How to access the ith column of a NumPy multidimensional array?

Although the question has been answered, let me mention some nuances.

Let's say you are interested in the first column of the array

arr = numpy.array([[1, 2],
                   [3, 4],
                   [5, 6]])

As you already know from other answers, to get it in the form of "row vector" (array of shape (3,)), you use slicing:

arr_col1_view = arr[:, 1]         # creates a view of the 1st column of the arr
arr_col1_copy = arr[:, 1].copy()  # creates a copy of the 1st column of the arr

To check if an array is a view or a copy of another array you can do the following:

arr_col1_view.base is arr  # True
arr_col1_copy.base is arr  # False

see ndarray.base.

Besides the obvious difference between the two (modifying arr_col1_view will affect the arr), the number of byte-steps for traversing each of them is different:

arr_col1_view.strides[0]  # 8 bytes
arr_col1_copy.strides[0]  # 4 bytes

see strides and this answer.

Why is this important? Imagine that you have a very big array A instead of the arr:

A = np.random.randint(2, size=(10000, 10000), dtype='int32')
A_col1_view = A[:, 1] 
A_col1_copy = A[:, 1].copy()

and you want to compute the sum of all the elements of the first column, i.e. A_col1_view.sum() or A_col1_copy.sum(). Using the copied version is much faster:

%timeit A_col1_view.sum()  # ~248 µs
%timeit A_col1_copy.sum()  # ~12.8 µs

This is due to the different number of strides mentioned before:

A_col1_view.strides[0]  # 40000 bytes
A_col1_copy.strides[0]  # 4 bytes

Although it might seem that using column copies is better, it is not always true for the reason that making a copy takes time too and uses more memory (in this case it took me approx. 200 µs to create the A_col1_copy). However if we needed the copy in the first place, or we need to do many different operations on a specific column of the array and we are ok with sacrificing memory for speed, then making a copy is the way to go.

In the case we are interested in working mostly with columns, it could be a good idea to create our array in column-major ('F') order instead of the row-major ('C') order (which is the default), and then do the slicing as before to get a column without copying it:

A = np.asfortranarray(A)   # or np.array(A, order='F')
A_col1_view = A[:, 1]
A_col1_view.strides[0]     # 4 bytes

%timeit A_col1_view.sum()  # ~12.6 µs vs ~248 µs

Now, performing the sum operation (or any other) on a column-view is as fast as performing it on a column copy.

Finally let me note that transposing an array and using row-slicing is the same as using the column-slicing on the original array, because transposing is done by just swapping the shape and the strides of the original array.

A[:, 1].strides[0]    # 40000 bytes
A.T[1, :].strides[0]  # 40000 bytes

Get the value of checked checkbox?

None of the above worked for me without throwing errors in the console when the box wasn't checked so I did something along these lines instead (onclick and the checkbox function are only being used for demo purposes, in my use case it's part of a much bigger form submission function):

_x000D_
_x000D_
function checkbox() {_x000D_
  var checked = false;_x000D_
  if (document.querySelector('#opt1:checked')) {_x000D_
     checked = true;_x000D_
  }_x000D_
  document.getElementById('msg').innerText = checked;_x000D_
}
_x000D_
<input type="checkbox" onclick="checkbox()" id="opt1"> <span id="msg">Click The Box</span>
_x000D_
_x000D_
_x000D_

What is the total amount of public IPv4 addresses?

According to Reserved IP addresses there are 588,514,304 reserved addresses and since there are 4,294,967,296 (2^32) IPv4 addressess in total, there are 3,706,452,992 public addresses.

And too many addresses in this post.

How to define partitioning of DataFrame?

Use the DataFrame returned by:

yourDF.orderBy(account)

There is no explicit way to use partitionBy on a DataFrame, only on a PairRDD, but when you sort a DataFrame, it will use that in it's LogicalPlan and that will help when you need to make calculations on each Account.

I just stumbled upon the same exact issue, with a dataframe that I want to partition by account. I assume that when you say "want to have the data partitioned so that all of the transactions for an account are in the same Spark partition", you want it for scale and performance, but your code doesn't depend on it (like using mapPartitions() etc), right?

Get Android Device Name

You can see answers at here Get Android Phone Model Programmatically

public String getDeviceName() {
   String manufacturer = Build.MANUFACTURER;
   String model = Build.MODEL;
   if (model.startsWith(manufacturer)) {
      return capitalize(model);
   } else {
      return capitalize(manufacturer) + " " + model;
   }
}


private String capitalize(String s) {
    if (s == null || s.length() == 0) {
        return "";
    }
    char first = s.charAt(0);
    if (Character.isUpperCase(first)) {
        return s;
    } else {
        return Character.toUpperCase(first) + s.substring(1);
    }
}

How to exclude records with certain values in sql select

One way:

SELECT DISTINCT sc.StoreId
FROM StoreClients sc
WHERE NOT EXISTS(
    SELECT * FROM StoreClients sc2 
    WHERE sc2.StoreId = sc.StoreId AND sc2.ClientId = 5)

WP -- Get posts by category?

You can use 'category_name' in parameters. http://codex.wordpress.org/Template_Tags/get_posts

Note: The category_name parameter needs to be a string, in this case, the category name.

Convert System.Drawing.Color to RGB and Hex Value

You could keep it simple and use the native color translator:

Color red = ColorTranslator.FromHtml("#FF0000");
string redHex = ColorTranslator.ToHtml(red);

Then break the three color pairs into integer form:

int value = int.Parse(hexValue, System.Globalization.NumberStyles.HexNumber);

Sorting dropdown alphabetically in AngularJS

var module = angular.module("example", []);

module.controller("orderByController", function ($scope) {
    $scope.orderByValue = function (value) {
        return value;
    };

    $scope.items = ["c", "b", "a"];
    $scope.objList = [
        {
            "name": "c"
        }, {
            "name": "b"
        }, {
            "name": "a"
        }];
        $scope.item = "b";
    });

http://jsfiddle.net/Nfv42/65/

Error sending json in POST to web API service

It require to include Content-Type:application/json in web api request header section when not mention any content then by default it is Content-Type:text/plain passes to request.

Best way to test api on postman tool.

Create nice column output in python

data = [['a', 'b', 'c'], ['aaaaaaaaaa', 'b', 'c'], ['a', 'bbbbbbbbbb', 'c']]

col_width = max(len(word) for row in data for word in row) + 2  # padding
for row in data:
    print "".join(word.ljust(col_width) for word in row)

a            b            c            
aaaaaaaaaa   b            c            
a            bbbbbbbbbb   c   

What this does is calculate the longest data entry to determine the column width, then use .ljust() to add the necessary padding when printing out each column.

Can I return the 'id' field after a LINQ insert?

Try this:

MyContext Context = new MyContext(); 
Context.YourEntity.Add(obj);
Context.SaveChanges();
int ID = obj._ID;

How do I change the text of a span element using JavaScript?

document.getElementById("myspan").textContent="newtext";

this will select dom-node with id myspan and change it text content to new text

Fatal error in launcher: Unable to create process using ""C:\Program Files (x86)\Python33\python.exe" "C:\Program Files (x86)\Python33\pip.exe""

I have similar problem when I reinstall my python, by uninstalling python3.7 and installing python3.8. But I solved it by removing the previous version of python directory. For me it was located here,

C:\Users\your-username\AppData\Local\Programs\Python

I deleted the folder named Python37 (for previous version) and keep Python38 (for updated version). This worked because python itself seems having a trouble on finding the right directory for your python scripts.

In vb.net, how to get the column names from a datatable

Do you have access to your database, if so just open it up and look up the column and use an SQL call to retrieve the needed.

A short example on a form to retrieve data from a database table:

Form contain only a GataGridView named DataGrid

Database name: DB.mdf

Table name: DBtable

Column names in table: Name as varchar(50), Age as int, Gender as bit.

Private Sub DatabaseTest_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    Public ConString As String = "Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Users\{username}\documents\visual studio 2010\Projects\Userapplication prototype v1.0\Userapplication prototype v1.0\Database\DB.mdf;" & "Integrated Security=True;User Instance=True"
    Dim conn As New SqlClient.SqlConnection
    Dim cmd As New SqlClient.SqlCommand
    Dim da As New SqlClient.SqlDataAdapter
    Dim dt As New DataTable
    Dim sSQL As String = String.Empty
    Try
        conn = New SqlClient.SqlConnection(ConString)
        conn.Open() 'connects to the database
        cmd.Connection = conn
        cmd.CommandType = CommandType.Text
        sSQL = "SELECT * FROM DBtable" 'Sql to be executed
        cmd.CommandText = sSQL 'makes the string a command
        da.SelectCommand = cmd 'puts the command into the sqlDataAdapter
        da.Fill(dt) 'populates the dataTable by performing the command above
        Me.DataGrid.DataSource = dt 'Updates the grid using the populated dataTable

        'the following is only if any errors happen:
        If dt.Rows.Count = 0 Then
            MsgBox("No record found!")
        End If
    Catch ex As Exception
        MsgBox(ErrorToString)
    Finally
        conn.Close() 'closes the connection again so it can be accessed by other users or programs
    End Try
End Sub

This will fetch all the rows and columns from your database table for review.
If you want to only fetch the names just change the sql call with: "SELECT Name FROM DBtable" this way the DataGridView will only show the column names.

I'm only a rookie but i would strongly advise to get rid of theses auto generate wizards. Using SQL you have full access to your database and what happens.
Also one last thing, if your database doesn't use SQLClient just change it to OleDB.

Example: "Dim conn As New SqlClient.SqlConnection" becomes: Dim conn As New OleDb.OleDbConnection

Bash script to calculate time elapsed

I find it very clean to use the internal variable "$SECONDS"

SECONDS=0 ; sleep 10 ; echo $SECONDS

How to redirect both stdout and stderr to a file

You can do it like that 2>&1:

 command > file 2>&1

Checking if a variable is an integer

Probably you are looking for something like this:

Accept "2.0 or 2.0 as an INT but reject 2.1 and "2.1"

num = 2.0

if num.is_a? String num = Float(num) rescue false end

new_num = Integer(num) rescue false

puts num

puts new_num

puts num == new_num

Reduce size of legend area in barplot

The cex parameter will do that for you.

a <- c(3, 2, 2, 2, 1, 2 )
barplot(a, beside = T,
        col = 1:6, space = c(0, 2))
legend("topright", 
       legend = c("a", "b", "c", "d", "e", "f"), 
       fill = 1:6, ncol = 2,
       cex = 0.75)

The plot

Change language for bootstrap DateTimePicker

you need to add the javascript language file,after the moment library, example:

<script type="text/javascript" src="js/moment/moment.js"></script>
<script type="text/javascript" src="js/moment/es.js"></script>

now you can set a language.

<script type="text/javascript">
$(function () {
  $('#datetimepicker1').datetimepicker({locale:'es'});
});
</script>

Here are all language: https://github.com/moment/moment

How to name and retrieve a stash by name in git?

Stashes are not meant to be permanent things like you want. You'd probably be better served using tags on commits. Construct the thing you want to stash. Make a commit out of it. Create a tag for that commit. Then roll back your branch to HEAD^. Now when you want to reapply that stash you can use git cherry-pick -n tagname (-n is --no-commit).

How to get value of a div using javascript

As I said in the comments, a <div> element does not have a value attribute. Although (very) bad, it can be accessed as:

console.log(document.getElementById('demo').getAttribute);

I suggest using HTML5 data-* attributes rather. Something like this:

<div id="demo" data-myValue="1">...</div>

in which case you could access it using:

element.getAttribute('data-myValue');
//Or using jQuery:
$('#demo').data('myValue');

Screen width in React Native

In React-Native we have an Option called Dimensions

Include Dimensions at the top var where you have include the Image,and Text and other components.

Then in your Stylesheets you can use as below,

ex: {
width: Dimensions.get('window').width,
height: Dimensions.get('window').height
}

In this way you can get the device window and height.

R - Markdown avoiding package loading messages

```{r results='hide', message=FALSE, warning=FALSE}
library(RJSONIO)
library(AnotherPackage)
```

see Chunk Options in the Knitr docs

HTML span align center not working?

On top of all the other explanations, I believe you're using equal "=" sign, instead of colon ":":

<span style="border:1px solid red;text-align=center">

It should be:

<span style="border:1px solid red;text-align:center">

Android XXHDPI resources

The DPI of the screen of the Nexus 10 is ±300, which is in the unofficial xhdpi range of 280-400.

Usually, devices use resources designed for their density. But there are exceptions, and exceptions might be added in the future. The Nexus 10 uses xxhdpi resources when it comes to launcher icons.

The standard quantised DPI for xxhdpi is 480 (which means screens with a DPI somewhere in the range of 400-560 are probably xxhdpi).

How to fix the error "Windows SDK version 8.1" was not found?

I realize this post is a few years old, but I just wanted to extend this to anyone still struggling through this issue.

The company I work for still uses VS2015 so in turn I still use VS2015. I recently started working on a RPC application using C++ and found the need to download the Win32 Templates. Like many others I was having this "SDK 8.1 was not found" issue. i took the following corrective actions with no luck.

  • I found the SDK through Micrsoft at the following link https://developer.microsoft.com/en-us/windows/downloads/sdk-archive/ as referenced above and downloaded it.
  • I located my VS2015 install in Apps & Features and ran the repair.
  • I completely uninstalled my VS2015 and reinstalled it.
  • I attempted to manually point my console app "Executable" and "Include" directories to the C:\Program Files (x86)\Microsoft SDKs\Windows Kits\8.1 and C:\Program Files (x86)\Microsoft SDKs\Windows\v8.1A\bin\NETFX 4.5.1 Tools.

None of the attempts above corrected the issue for me...

I then found this article on social MSDN https://social.msdn.microsoft.com/Forums/office/en-US/5287c51b-46d0-4a79-baad-ddde36af4885/visual-studio-cant-find-windows-81-sdk-when-trying-to-build-vs2015?forum=visualstudiogeneral

Finally what resolved the issue for me was:

  • Uninstalling and reinstalling VS2015.
  • Locating my installed "Windows Software Development Kit for Windows 8.1" and running the repair.
  • Checked my "C:\Program Files (x86)\Microsoft SDKs\Windows Kits\8.1" to verify the "DesignTime" folder was in fact there.
  • Opened VS created a Win32 Console application and comiled with no errors or issues

I hope this saves anyone else from almost 3 full days of frustration and loss of productivity.

Get next element in foreach loop

If the indexes are continuous:

foreach ($arr as $key => $val) {
   if (isset($arr[$key+1])) {
      echo $arr[$key+1]; // next element
   } else {
     // end of array reached
   }
}

How to get value from form field in django framework?

To retrieve data from form which send post request you can do it like this

def login_view(request):
    if(request.POST):
        login_data = request.POST.dict()
        username = login_data.get("username")
        password = login_data.get("password")
        user_type = login_data.get("user_type")
        print(user_type, username, password)
        return HttpResponse("This is a post request")
    else:
        return render(request, "base.html")

How can I increment a char?

def doubleChar(str):
    result = ''
    for char in str:
        result += char * 2
    return result

print(doubleChar("amar"))

output:

aammaarr

Creating a UICollectionView programmatically

You can handle custom cell in uicollection view see below code.enter image description here

- (void)viewDidLoad
{
  UINib *nib2 = [UINib nibWithNibName:@"YourCustomCell" bundle:nil];
    [CollectionVW registerNib:nib2 forCellWithReuseIdentifier:@"YourCustomCell"];


    UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
    [flowLayout setItemSize:CGSizeMake(200, 230)];
    flowLayout.minimumInteritemSpacing = 0;
    [flowLayout setScrollDirection:UICollectionViewScrollDirectionVertical];
    [CollectionVW setCollectionViewLayout:flowLayout];

    [CollectionVW reloadData];
}

#pragma mark - COLLECTIONVIEW
#pragma mark Collection View CODE

-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return 1;
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return Array.count;
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cellIdentifier = @"YourCustomCell";
    YourCustomCell *cell = (YourCustomCell *)[collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];

    cell.MainIMG.image=[UIImage imageNamed:[Array objectAtIndex:indexPath.row]];


    return cell;
}

-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
}

#pragma mark Collection view layout things
// Layout: Set cell size
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    CGSize mElementSize;
    mElementSize=CGSizeMake(kScreenWidth/3.4, 150);
    return mElementSize;
}


- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section
{
    return 5.0;
}

// Layout: Set Edges
- (UIEdgeInsets)collectionView: (UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section
{
    if (isIphone5 || isiPhone4)
    {
        return UIEdgeInsetsMake(15,15,5,15);  // top, left, bottom, right
    }
    else if (isIphone6)
    {
        return UIEdgeInsetsMake(15,15,5,15);  // top, left, bottom, right
    }
    else if (isIphone6P)
    {
        return UIEdgeInsetsMake(15,15,5,15);  // top, left, bottom, right
    }

    return UIEdgeInsetsMake(15,15,5,15);  // top, left, bottom, right
}

Capturing URL parameters in request.GET

This is another alternate solution that can be implemented:

In the URL configuration:

urlpatterns = [path('runreport/<str:queryparams>', views.get)]

In the views:

list2 = queryparams.split("&")

Grep only the first match and stop

My grep-a-like program ack has a -1 option that stops at the first match found anywhere. It supports the -m 1 that @mvp refers to as well. I put it in there because if I'm searching a big tree of source code to find something that I know exists in only one file, it's unnecessary to find it and have to hit Ctrl-C.

Calling a PHP function from an HTML form in the same file

Take a look at this example:

<!DOCTYPE HTML> 
<html>
<head>
</head>
<body> 

<?php
// define variables and set to empty values
$name = $email = $gender = $comment = $website = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {
   $name = test_input($_POST["name"]);
   $email = test_input($_POST["email"]);
   $website = test_input($_POST["website"]);
   $comment = test_input($_POST["comment"]);
   $gender = test_input($_POST["gender"]);
}

function test_input($data) {
   $data = trim($data);
   $data = stripslashes($data);
   $data = htmlspecialchars($data);
   return $data;
}
?>

<h2>PHP Form Validation Example</h2>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>"> 
   Name: <input type="text" name="name">
   <br><br>
   E-mail: <input type="text" name="email">
   <br><br>
   Website: <input type="text" name="website">
   <br><br>
   Comment: <textarea name="comment" rows="5" cols="40"></textarea>
   <br><br>
   Gender:
   <input type="radio" name="gender" value="female">Female
   <input type="radio" name="gender" value="male">Male
   <br><br>
   <input type="submit" name="submit" value="Submit"> 
</form>

<?php
echo "<h2>Your Input:</h2>";
echo $name;
echo "<br>";
echo $email;
echo "<br>";
echo $website;
echo "<br>";
echo $comment;
echo "<br>";
echo $gender;
?>

</body>
</html>

Is there a way to pass javascript variables in url?

Do you mean include javascript variable values in the query string of the URL?

Yes:

 window.location.href = "http://www.gorissen.info/Pierre/maps/googleMapLocation.php?lat="+var1+"&lon="+var2+"&setLatLon="+varEtc;

How to initialize a struct in accordance with C programming language standards

Structure in C can be declared and initialized like this:

typedef struct book
{
    char title[10];
    char author[10];
    float price;
} book;

int main() {
    book b1={"DS", "Ajay", 250.0};

    printf("%s \t %s \t %f", b1.title, b1.author, b1.price);

    return 0;
}

Error "library not found for" after putting application in AdMob

Running 'pod update' in my project fixed my problem with the 'library not found for -lSTPopup' error.

Remarking Trevor Panhorst's answer:

"Just be careful doing pod update if you don't use explicit versions in your pod file."

How to run certain task every day at a particular time using ScheduledExecutorService?

As with the present java SE 8 release with it's excellent date time API with java.time these kind of calculation can be done more easily instead of using java.util.Calendar and java.util.Date.

Now as a sample example for scheduling a task with your use case:

ZonedDateTime now = ZonedDateTime.now(ZoneId.of("America/Los_Angeles"));
ZonedDateTime nextRun = now.withHour(5).withMinute(0).withSecond(0);
if(now.compareTo(nextRun) > 0)
    nextRun = nextRun.plusDays(1);

Duration duration = Duration.between(now, nextRun);
long initalDelay = duration.getSeconds();

ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);            
scheduler.scheduleAtFixedRate(new MyRunnableTask(),
    initalDelay,
    TimeUnit.DAYS.toSeconds(1),
    TimeUnit.SECONDS);

The initalDelay is computed to ask the scheduler to delay the execution in TimeUnit.SECONDS. Time difference issues with unit milliseconds and below seems to be negligible for this use case. But you can still make use of duration.toMillis() and TimeUnit.MILLISECONDS for handling the scheduling computaions in milliseconds.

And also TimerTask is better for this or ScheduledExecutorService?

NO: ScheduledExecutorService seemingly better than TimerTask. StackOverflow has already an answer for you.

From @PaddyD,

You still have the issue whereby you need to restart this twice a year if you want it to run at the right local time. scheduleAtFixedRate won't cut it unless you are happy with the same UTC time all year.

As it is true and @PaddyD already has given a workaround(+1 to him), I am providing a working example with Java8 date time API with ScheduledExecutorService. Using daemon thread is dangerous

class MyTaskExecutor
{
    ScheduledExecutorService executorService = Executors.newScheduledThreadPool(1);
    MyTask myTask;
    volatile boolean isStopIssued;

    public MyTaskExecutor(MyTask myTask$) 
    {
        myTask = myTask$;

    }

    public void startExecutionAt(int targetHour, int targetMin, int targetSec)
    {
        Runnable taskWrapper = new Runnable(){

            @Override
            public void run() 
            {
                myTask.execute();
                startExecutionAt(targetHour, targetMin, targetSec);
            }

        };
        long delay = computeNextDelay(targetHour, targetMin, targetSec);
        executorService.schedule(taskWrapper, delay, TimeUnit.SECONDS);
    }

    private long computeNextDelay(int targetHour, int targetMin, int targetSec) 
    {
        LocalDateTime localNow = LocalDateTime.now();
        ZoneId currentZone = ZoneId.systemDefault();
        ZonedDateTime zonedNow = ZonedDateTime.of(localNow, currentZone);
        ZonedDateTime zonedNextTarget = zonedNow.withHour(targetHour).withMinute(targetMin).withSecond(targetSec);
        if(zonedNow.compareTo(zonedNextTarget) > 0)
            zonedNextTarget = zonedNextTarget.plusDays(1);

        Duration duration = Duration.between(zonedNow, zonedNextTarget);
        return duration.getSeconds();
    }

    public void stop()
    {
        executorService.shutdown();
        try {
            executorService.awaitTermination(1, TimeUnit.DAYS);
        } catch (InterruptedException ex) {
            Logger.getLogger(MyTaskExecutor.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
}

Note:

  • MyTask is an interface with function execute.
  • While stopping ScheduledExecutorService, Always use awaitTermination after invoking shutdown on it: There's always a likelihood your task is stuck / deadlocking and the user would wait forever.

The previous example I gave with Calender was just an idea which I did mention, I avoided exact time calculation and Daylight saving issues. Updated the solution on per the complain of @PaddyD

How to deal with certificates using Selenium?

Whenever I run into this issue with newer browsers, I just use AppRobotic Personal edition to click specific screen coordinates, or tab through the buttons and click.

Basically it's just using its macro functionality, but won't work on headless setups though.

How to create an array of 20 random bytes?

If you want a cryptographically strong random number generator (also thread safe) without using a third party API, you can use SecureRandom.

Java 6 & 7:

SecureRandom random = new SecureRandom();
byte[] bytes = new byte[20];
random.nextBytes(bytes);

Java 8 (even more secure):

byte[] bytes = new byte[20];
SecureRandom.getInstanceStrong().nextBytes(bytes);

How can I check if a JSON is empty in NodeJS?

If you have compatibility with Object.keys, and node does have compatibility, you should use that for sure.

However, if you do not have compatibility, and for any reason using a loop function is out of the question - like me, I used the following solution:

JSON.stringify(obj) === '{}'

Consider this solution a 'last resort' use only if must.

See in the comments "there are many ways in which this solution is not ideal".

I had a last resort scenario, and it worked perfectly.

Table fixed header and scrollable body

Now that “all” browsers support ES6, I’ve incorporated the various suggestions above into a JavaScript class that takes a table as an argument and makes the body scrollable. It lets the browser’s layout engine determine header and body cell widths, and then makes the column widths match each other.

The height of a table can be set explicitly, or made to fill the remaining part of the browser window, and provides callbacks for events such as viewport resizing and/or details elements opening or closing.

Multi-row header support is available, and is especially effective if the table uses the id/headers attributes for accessibility as specified in the WCAC Guidelines, which is not as onerous a requirement as it might seem.

The code does not depend on any libraries, but plays nicely with them if they are being used. (Tested on pages that use JQuery).

The code and sample usage are available on Github.

Hashing a string with Sha256

This work for me in .NET Core 3.1.
But not in .NET 5 preview 7.

using System;
using System.Security.Cryptography;
using System.Text;

namespace PortalAplicaciones.Shared.Models
{
    public class Encriptar
    {
        public static string EncriptaPassWord(string Password)
        {
            try
            {
                SHA256Managed hasher = new SHA256Managed();

                byte[] pwdBytes = new UTF8Encoding().GetBytes(Password);
                byte[] keyBytes = hasher.ComputeHash(pwdBytes);

                hasher.Dispose();
                return Convert.ToBase64String(keyBytes);
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message, ex);
            }
        }  
    }
}
 

How to pass a callback as a parameter into another function

You can use JavaScript CallBak like this:

var a;

function function1(callback) {
 console.log("First comeplete");
 a = "Some value";
 callback();
}
function function2(){
 console.log("Second comeplete:", a);
}


function1(function2);

Or Java Script Promise:

let promise = new Promise(function(resolve, reject) { 
  // do function1 job
  let a = "Your assign value"
  resolve(a);
});

promise.then(             

function(a) {
 // do function2 job with function1 return value;
 console.log("Second comeplete:", a);
},
function(error) { 
 console.log("Error found");
});

git checkout all the files

Other way which I found useful is:

git checkout <wildcard> 

Example:

git checkout *.html

More generally:

git checkout <branch> <filename/wildcard>

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

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

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

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

How to prevent Browser cache on Angular 2 site?

angular-cli resolves this by providing an --output-hashing flag for the build command (versions 6/7, for later versions see here). Example usage:

ng build --output-hashing=all

Bundling & Tree-Shaking provides some details and context. Running ng help build, documents the flag:

--output-hashing=none|all|media|bundles (String)

Define the output filename cache-busting hashing mode.
aliases: -oh <value>, --outputHashing <value>

Although this is only applicable to users of angular-cli, it works brilliantly and doesn't require any code changes or additional tooling.

Update

A number of comments have helpfully and correctly pointed out that this answer adds a hash to the .js files but does nothing for index.html. It is therefore entirely possible that index.html remains cached after ng build cache busts the .js files.

At this point I'll defer to How do we control web page caching, across all browsers?

Is Java a Compiled or an Interpreted programming language ?

Java implementations typically use a two-step compilation process. Java source code is compiled down to bytecode by the Java compiler. The bytecode is executed by a Java Virtual Machine (JVM). Modern JVMs use a technique called Just-in-Time (JIT) compilation to compile the bytecode to native instructions understood by hardware CPU on the fly at runtime.

Some implementations of JVM may choose to interpret the bytecode instead of JIT compiling it to machine code, and running it directly. While this is still considered an "interpreter," It's quite different from interpreters that read and execute the high level source code (i.e. in this case, Java source code is not interpreted directly, the bytecode, output of Java compiler, is.)

It is technically possible to compile Java down to native code ahead-of-time and run the resulting binary. It is also possible to interpret the Java code directly.

To summarize, depending on the execution environment, bytecode can be:

  • compiled ahead of time and executed as native code (similar to most C++ compilers)
  • compiled just-in-time and executed
  • interpreted
  • directly executed by a supported processor (bytecode is the native instruction set of some CPUs)

Invoking modal window in AngularJS Bootstrap UI using JavaScript

The AngularJS Bootstrap website hasn't been updated with the latest documentation. About 3 months ago pkozlowski-opensource authored a change to separate out $modal from $dialog commit is below:

https://github.com/angular-ui/bootstrap/commit/d7a48523e437b0a94615350a59be1588dbdd86bd

In that commit he added new documentation for $modal, which can be found below:

https://github.com/angular-ui/bootstrap/blob/d7a48523e437b0a94615350a59be1588dbdd86bd/src/modal/docs/readme.md.

Hope this helps!

Android Color Picker

I know the question is old, but if someone is looking for a great new android color picker that use material design I have forked an great project from github and made a simple-to-use android color picker dialog.

This is the project: Android Color Picker

Android Color Picker dialog

enter image description here

HOW TO USE IT

Adding the library to your project

The aar artifact is available at the jcenter repository. Declare the repository and the dependency in your build.gradle.

(root)

repositories {
    jcenter()
}

(module)

dependencies {
    compile 'com.pes.materialcolorpicker:library:1.0.2'
}

Use the library

Create a color picker dialog object

final ColorPicker cp = new ColorPicker(MainActivity.this, defaultColorR, defaultColorG, defaultColorB);

defaultColorR, defaultColorG, defaultColorB are 3 integer ( value 0-255) for the initialization of the color picker with your custom color value. If you don't want to start with a color set them to 0 or use only the first argument

Then show the dialog (when & where you want) and save the selected color

/* Show color picker dialog */
cp.show();

/* On Click listener for the dialog, when the user select the color */
Button okColor = (Button)cp.findViewById(R.id.okColorButton);

okColor.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
            
        /* You can get single channel (value 0-255) */
        selectedColorR = cp.getRed();
        selectedColorG = cp.getGreen();
        selectedColorB = cp.getBlue();
            
        /* Or the android RGB Color (see the android Color class reference) */
        selectedColorRGB = cp.getColor();

        cp.dismiss();
    }
});

That's all :)

Can't access to HttpContext.Current

Adding a bit to mitigate the confusion here. Even though Darren Davies' (accepted) answer is more straight forward, I think Andrei's answer is a better approach for MVC applications.

The answer from Andrei means that you can use HttpContext just as you would use System.Web.HttpContext.Current. For example, if you want to do this:

System.Web.HttpContext.Current.User.Identity.Name

you should instead do this:

HttpContext.User.Identity.Name

Both achieve the same result, but (again) in terms of MVC, the latter is more recommended.

Another good and also straight forward information regarding this matter can be found here: Difference between HttpContext.Current and Controller.Context in MVC ASP.NET.

Allowed memory size of 536870912 bytes exhausted in Laravel

Sometime limiting your data is also helpful, for example checkout the followings:

//This caused error:
print_r($request);

//This resolved issue:
print_r($request->all());




    

Load different application.yml in SpringBoot Test

Spring-boot framework allows us to provide YAML files as a replacement for the .properties file and it is convenient.The keys in property files can be provided in YAML format in application.yml file in the resource folder and spring-boot will automatically take it up.Keep in mind that the yaml format has to keep the spaces correct for the value to be read correctly.

You can use the @Value("${property}") to inject the values from the YAML files. Also Spring.active.profiles can be given to differentiate between different YAML for different environments for convenient deployment.

For testing purposes, the test YAML file can be named like application-test.yml and placed in the resource folder of the test directory.

If you are specifying the application-test.yml and provide the spring test profile in the .yml, then you can use the @ActiveProfiles('test') annotation to direct spring to take the configurations from the application-test.yml that you have specified.

@RunWith(SpringRunner.class)
@SpringBootTest(classes = ApplicationTest.class)
@ActiveProfiles("test")
public class MyTest {
 ...
}

If you are using JUnit 5 then no need for other annotations as @SpringBootTest already include the springrunner annotation. Keeping a separate main ApplicationTest.class enables us to provide separate configuration classes for tests and we can prevent the default configuration beans from loading by excluding them from a component scan in the test main class. You can also provide the profile to be loaded there.

@SpringBootApplication(exclude=SecurityAutoConfiguration.class)
public class ApplicationTest {
 
    public static void main(String[] args) {
        SpringApplication.run(ApplicationTest.class, args);
    }
}

Here is the link for Spring documentation regarding the use of YAML instead of .properties file(s): https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-external-config.html

HTML tag inside JavaScript

<div id="demo"></div>

<input type="submit" name="submit" id="submit" value="Submit" onClick="return empty()">


<script type="text/javascript">
        function empty()
        {
          var x;
          x = document.getElementById("feedbackpost").value;
          if (x == "")
           {
             var demo = document.getElementById("demo");
             demo.innerHTML =document.write='<h1>Hello member</h1>';
              return false;
           };
        }
    </script>

Regular expression to extract URL from an HTML link

You can use this.

<a[^>]+href=["'](.*?)["']

onclick="location.href='link.html'" does not load page in Safari

You can try this:

 <a href="link.html">
       <input type="button" value="Visit Page" />
    </a>

This will create button inside a link and it works on any browser

How do I update the password for Git?

I was pushing into the repository for the first time. So there was no HEAD defined.

The easiest way would be to:

git push -u origin master

It will then prompt for the password, and once you enter that it will be saved automatically, and you will be able to push.

Auto number column in SharePoint list

You can't add a new unique auto-generated ID to a SharePoint list, but there already is one there! If you edit the "All Items" view you will see a list of columns that do not have the display option checked.

There are quite a few of these columns that exist but that are never displayed, like "Created By" and "Created". These fields are used within SharePoint, but they are not displayed by default so as not to clutter up the display. You can't edit these fields, but you can display them to the user. if you check the "Display" box beside the ID field you will get a unique and auto-generated ID field displayed in your list.

Check out: Unique ID in SharePoint list

How can I check for IsPostBack in JavaScript?

Here is one way (put this in Page_Load):

if (this.IsPostBack)
{
    Page.ClientScript.RegisterStartupScript(this.GetType(),"PostbackKey","<script type='text/javascript'>var isPostBack = true;</script>");
}

Then just check that variable in the JS.

function to return a string in java

In Java, a String is a reference to heap-allocated storage. Returning "ans" only returns the reference so there is no need for stack-allocated storage. In fact, there is no way in Java to allocate objects in stack storage.

I would change to this, though. You don't need "ans" at all.

return String.format("%d:%d", mins, secs);

IIS7: A process serving application pool 'YYYYY' suffered a fatal communication error with the Windows Process Activation Service

I ran into this recently. Our organization restricts the accounts that run application pools to a select list of servers in Active Directory. I found that I had not added one of the machines hosting the application to the "Log On To" list for the account in AD.

What exactly is the function of Application.CutCopyMode property in Excel

There is a good explanation at https://stackoverflow.com/a/33833319/903783

The values expected seem to be xlCopy and xlCut according to xlCutCopyMode enumeration (https://msdn.microsoft.com/en-us/VBA/Excel-VBA/articles/xlcutcopymode-enumeration-excel), but the 0 value (this is what False equals to in VBA) seems to be useful to clear Excel data put on the Clipboard.

What is the maximum length of a Push Notification alert text?

According to the WWDC 713_hd_whats_new_in_ios_notifications. The previous size limit of 256 bytes for a push payload has now been increased to 2 kilobytes for iOS 8.

Source: http://asciiwwdc.com/2014/sessions/713?q=notification#1414.0

Sort Java Collection

To be super clear, Collection.sort(list, compartor) does not return anything so something like this list = Collection.sort(list, compartor); will throw an error (void cannot be converted to [list type]) and should instead be Collection.sort(list, compartor)

How to split a string in shell and get the last field

One way:

var1="1:2:3:4:5"
var2=${var1##*:}

Another, using an array:

var1="1:2:3:4:5"
saveIFS=$IFS
IFS=":"
var2=($var1)
IFS=$saveIFS
var2=${var2[@]: -1}

Yet another with an array:

var1="1:2:3:4:5"
saveIFS=$IFS
IFS=":"
var2=($var1)
IFS=$saveIFS
count=${#var2[@]}
var2=${var2[$count-1]}

Using Bash (version >= 3.2) regular expressions:

var1="1:2:3:4:5"
[[ $var1 =~ :([^:]*)$ ]]
var2=${BASH_REMATCH[1]}

is there something like isset of php in javascript/jQuery?

You can just:

if(variable||variable===0){
    //Yes it is set
    //do something
}
else {
    //No it is not set
    //Or its null
    //do something else 
}