Programs & Examples On #Dompdf

An HTML to PDF converter written in PHP

file_put_contents: Failed to open stream, no such file or directory

There is definitly a problem with the destination folder path.

Your above error message says, it wants to put the contents to a file in the directory /files/grantapps/, which would be beyond your vhost, but somewhere in the system (see the leading absolute slash )

You should double check:

  • Is the directory /home/username/public_html/files/grantapps/ really present.
  • Contains your loop and your file_put_contents-Statement the absolute path /home/username/public_html/files/grantapps/

how to save DOMPDF generated content to file?

<?php
$content='<table width="100%" border="1">';
$content.='<tr><th>name</th><th>email</th><th>contact</th><th>address</th><th>city</th><th>country</th><th>postcode</th></tr>';
for ($index = 0; $index < 10; $index++) { 
$content.='<tr><td>nadim</td><td>[email protected]</td><td>7737033665</td><td>247 dehligate</td><td>udaipur</td><td>india</td><td>313001</td></tr>';
}
$content.='</table>';
//$html = file_get_contents('pdf.php');
if(isset($_POST['pdf'])){
    require_once('./dompdf/dompdf_config.inc.php');
    $dompdf = new DOMPDF;                        
    $dompdf->load_html($content);
    $dompdf->render();
    $dompdf->stream("hello.pdf");
}
?>
<html>
    <body>
        <form action="#" method="post">        
            <button name="pdf" type="submit">export</button>
        <table width="100%" border="1">
           <tr><th>name</th><th>email</th><th>contact</th><th>address</th><th>city</th><th>country</th><th>postcode</th></tr>         
            <?php for ($index = 0; $index < 10; $index++) { ?>
            <tr><td>nadim</td><td>[email protected]</td><td>7737033665</td><td>247 dehligate</td><td>udaipur</td><td>india</td><td>313001</td></tr>
            <?php } ?>            
        </table>        
        </form>        
    </body>
</html>

Hide div after a few seconds

jquery offers a variety of methods to hide the div in a timed manner that do not require setting up and later clearing or resetting interval timers or other event handlers. Here are a few examples.

Pure hide, one second delay

// hide in one second
$('#mydiv').delay(1000).hide(0); 

Pure hide, no delay

// hide immediately
$('#mydiv').delay(0).hide(0); 

Animated hide

// start hide in one second, take 1/2 second for animated hide effect
$('#mydiv').delay(1000).hide(500); 

fade out

// start fade out in one second, take 300ms to fade
$('#mydiv').delay(1000).fadeOut(300); 

Additionally, the methods can take a queue name or function as a second parameter (depending on method). Documentation for all the calls above and other related calls can be found here: https://api.jquery.com/category/effects/

Center the nav in Twitter Bootstrap

For anyone needing this for Bootstrap 3, it is now much easier.

The new nav-justified class can be used to center all of the navbar links..

http://www.bootply.com/g3g125MLGr

<div class="navbar">
  <ul class="nav nav-justified" id="myNav">
    <li><a href="#">Home</a></li>
    <li><a href="#">Link</a></li>
    <li><a href="#">Link</a></li>
    <li><a href="#">Link</a></li>
    <li><a href="#">Link</a></li>
    <li><a href="#">Link</a></li>
    <li><a href="#">Link</a></li>
  </ul>
</div>

Or with a little CSS you can center just the brand/logo, and keep the left/right links separate..

http://www.bootply.com/3iSOTAyumP

What is RSS and VSZ in Linux memory management

RSS is the Resident Set Size and is used to show how much memory is allocated to that process and is in RAM. It does not include memory that is swapped out. It does include memory from shared libraries as long as the pages from those libraries are actually in memory. It does include all stack and heap memory.

VSZ is the Virtual Memory Size. It includes all memory that the process can access, including memory that is swapped out, memory that is allocated, but not used, and memory that is from shared libraries.

So if process A has a 500K binary and is linked to 2500K of shared libraries, has 200K of stack/heap allocations of which 100K is actually in memory (rest is swapped or unused), and it has only actually loaded 1000K of the shared libraries and 400K of its own binary then:

RSS: 400K + 1000K + 100K = 1500K
VSZ: 500K + 2500K + 200K = 3200K

Since part of the memory is shared, many processes may use it, so if you add up all of the RSS values you can easily end up with more space than your system has.

The memory that is allocated also may not be in RSS until it is actually used by the program. So if your program allocated a bunch of memory up front, then uses it over time, you could see RSS going up and VSZ staying the same.

There is also PSS (proportional set size). This is a newer measure which tracks the shared memory as a proportion used by the current process. So if there were two processes using the same shared library from before:

PSS: 400K + (1000K/2) + 100K = 400K + 500K + 100K = 1000K

Threads all share the same address space, so the RSS, VSZ and PSS for each thread is identical to all of the other threads in the process. Use ps or top to view this information in linux/unix.

There is way more to it than this, to learn more check the following references:

Also see:

Write Base64-encoded image to file

import java.util.Base64;

.... Just making it clear that this answer uses the java.util.Base64 package, without using any third-party libraries.

String crntImage=<a valid base 64 string>

byte[] data = Base64.getDecoder().decode(crntImage);

try( OutputStream stream = new FileOutputStream("d:/temp/abc.pdf") ) 
{
   stream.write(data);
}
catch (Exception e) 
{
   System.err.println("Couldn't write to file...");
}

Axios Delete request with body and headers?

I had the same issue I solved it like that:

axios.delete(url, {data:{username:"user", password:"pass"}, headers:{Authorization: "token"}})

Assignment makes pointer from integer without cast

As others already noted, in one case you are attempting to return cString (which is a char * value in this context - a pointer) from a function that is declared to return a char (which is an integer). In another case you do the reverse: you are assigning a char return value to a char * pointer. This is what triggers the warnings. You certainly need to declare your return values as char *, not as char.

Note BTW that these assignments are in fact constraint violations from the language point of view (i.e. they are "errors"), since it is illegal to mix pointers and integers in C like that (aside from integral constant zero). Your compiler is simply too forgiving in this regard and reports these violations as mere "warnings".

What I also wanted to note is that in several answers you might notice the relatively strange suggestion to return void from your functions, since you are modifying the string in-place. While it will certainly work (since you indeed are modifying the string in-place), there's nothing really wrong with returning the same value from the function. In fact, it is a rather standard practice in C language where applicable (take a look at the standard functions like strcpy and others), since it enables "chaining" of function calls if you choose to use it, and costs virtually nothing if you don't use "chaining".

That said, the assignments in your implementation of compareString look complete superfluous to me (even though they won't break anything). I'd either get rid of them

int compareString(char cString1[], char cString2[]) { 
    // To lowercase 
    strToLower(cString1); 
    strToLower(cString2); 

    // Do regular strcmp 
    return strcmp(cString1, cString2); 
} 

or use "chaining" and do

int compareString(char cString1[], char cString2[]) { 
    return strcmp(strToLower(cString1), strToLower(cString2)); 
} 

(this is when your char * return would come handy). Just keep in mind that such "chained" function calls are sometimes difficult to debug with a step-by-step debugger.

As an additional, unrealted note, I'd say that implementing a string comparison function in such a destructive fashion (it modifies the input strings) might not be the best idea. A non-destructive function would be of a much greater value in my opinion. Instead of performing as explicit conversion of the input strings to a lower case, it is usually a better idea to implement a custom char-by-char case-insensitive string comparison function and use it instead of calling the standard strcmp.

Convert the values in a column into row names in an existing data frame

You can execute this in 2 simple statements:

row.names(samp) <- samp$names
samp[1] <- NULL

What is difference between arm64 and armhf?

armhf stands for "arm hard float", and is the name given to a debian port for arm processors (armv7+) that have hardware floating point support.

On the beaglebone black, for example:

:~$ dpkg --print-architecture
armhf

Although other commands (such as uname -a or arch) will just show armv7l

:~$ cat /proc/cpuinfo 
processor       : 0
model name      : ARMv7 Processor rev 2 (v7l)
BogoMIPS        : 995.32
Features        : half thumb fastmult vfp edsp thumbee neon vfpv3 tls
...

The vfpv3 listed under Features is what refers to the floating point support.

Incidentally, armhf, if your processor supports it, basically supersedes Raspbian, which if I understand correctly was mainly a rebuild of armhf with work arounds to deal with the lack of floating point support on the original raspberry pi's. Nowdays, of course, there's a whole ecosystem build up around Raspbian, so they're probably not going to abandon it. However, this is partly why the beaglebone runs straight debian, and that's ok even if you're used to Raspbian, unless you want some of the special included non-free software such as Mathematica.

How to check if image exists with given url?

$.ajax({
    url:'http://www.example.com/somefile.ext',
    type:'HEAD',
    error: function(){
            //do something depressing
    },
    success: function(){
            //do something cheerful :)
    }
});

from: http://www.ambitionlab.com/how-to-check-if-a-file-exists-using-jquery-2010-01-06

Is it possible to capture the stdout from the sh DSL command in the pipeline

You can try to use as well this functions to capture StdErr StdOut and return code.

def runShell(String command){
    def responseCode = sh returnStatus: true, script: "${command} &> tmp.txt" 
    def output =  readFile(file: "tmp.txt")

    if (responseCode != 0){
      println "[ERROR] ${output}"
      throw new Exception("${output}")
    }else{
      return "${output}"
    }
}

Notice:

&>name means 1>name 2>name -- redirect stdout and stderr to the file name

How to express a NOT IN query with ActiveRecord/Rails?

Can these forum ids be worked out in a pragmatic way? e.g. can you find these forums somehow - if that is the case you should do something like

Topic.all(:joins => "left join forums on (forums.id = topics.forum_id and some_condition)", :conditions => "forums.id is null")

Which would be more efficient than doing an SQL not in

Multipart File upload Spring Boot

In Controller, your method should be;

@RequestMapping(value = "/upload", method = RequestMethod.POST)
    public ResponseEntity<SaveResponse> uploadAttachment(@RequestParam("file") MultipartFile file, HttpServletRequest request) {
....

Further, you need to update application.yml (or application.properties) to support maximum file size and request size.

spring:
    http:
        multipart:
            max-file-size: 5MB
            max-request-size: 20MB

What is the point of "Initial Catalog" in a SQL Server connection string?

This is the initial database of the data source when you connect.

Edited for clarity:

If you have multiple databases in your SQL Server instance and you don't want to use the default database, you need some way to specify which one you are going to use.

In Angular, how to redirect with $location.path as $http.post success callback

Here is the changeLocation example from this article http://www.yearofmoo.com/2012/10/more-angularjs-magic-to-supercharge-your-webapp.html#apply-digest-and-phase

//be sure to inject $scope and $location
var changeLocation = function(url, forceReload) {
  $scope = $scope || angular.element(document).scope();
  if(forceReload || $scope.$$phase) {
    window.location = url;
  }
  else {
    //only use this if you want to replace the history stack
    //$location.path(url).replace();

    //this this if you want to change the URL and add it to the history stack
    $location.path(url);
    $scope.$apply();
  }
};

What exactly does Double mean in java?

Double is a wrapper class,

The Double class wraps a value of the primitive type double in an object. An object of type Double contains a single field whose type is double.

In addition, this class provides several methods for converting a double to a String and a String to a double, as well as other constants and methods useful when dealing with a double.

The double data type,

The double data type is a double-precision 64-bit IEEE 754 floating point. Its range of values is 4.94065645841246544e-324d to 1.79769313486231570e+308d (positive or negative). For decimal values, this data type is generally the default choice. As mentioned above, this data type should never be used for precise values, such as currency.

Check each datatype with their ranges : Java's Primitive Data Types.


Important Note : If you'r thinking to use double for precise values, you need to re-think before using it. Java Traps: double

Difference between Amazon EC2 and AWS Elastic Beanstalk

First off, EC2 and Elastic Compute Cloud are the same thing.

Next, AWS encompasses the range of Web Services that includes EC2 and Elastic Beanstalk. It also includes many others such as S3, RDS, DynamoDB, and all the others.

EC2

EC2 is Amazon's service that allows you to create a server (AWS calls these instances) in the AWS cloud. You pay by the hour and only what you use. You can do whatever you want with this instance as well as launch n number of instances.

Elastic Beanstalk

Elastic Beanstalk is one layer of abstraction away from the EC2 layer. Elastic Beanstalk will setup an "environment" for you that can contain a number of EC2 instances, an optional database, as well as a few other AWS components such as a Elastic Load Balancer, Auto-Scaling Group, Security Group. Then Elastic Beanstalk will manage these items for you whenever you want to update your software running in AWS. Elastic Beanstalk doesn't add any cost on top of these resources that it creates for you. If you have 10 hours of EC2 usage, then all you pay is 10 compute hours.

Running Wordpress

For running Wordpress, it is whatever you are most comfortable with. You could run it straight on a single EC2 instance, you could use a solution from the AWS Marketplace, or you could use Elastic Beanstalk.

What to pick?

In the case that you want to reduce system operations and just focus on the website, then Elastic Beanstalk would be the best choice for that. Elastic Beanstalk supports a PHP stack (as well as others). You can keep your site in version control and easily deploy to your environment whenever you make changes. It will also setup an Autoscaling group which can spawn up more EC2 instances if traffic is growing.

Here's the first result off of Google when searching for "elastic beanstalk wordpress": https://www.otreva.com/blog/deploying-wordpress-amazon-web-services-aws-ec2-rds-via-elasticbeanstalk/

Best way to encode Degree Celsius symbol into web page?

If using Java-JSP, What worked for me is to paste below in JSP page

<%@ page contentType="text/html; charset=UTF-8" %>

Curl Command to Repeat URL Request

If you want to add an interval before executing the cron the next time you can add a sleep

for i in {1..100}; do echo $i && curl "http://URL" >> /tmp/output.log && sleep 120; done

What are Transient and Volatile Modifiers?

volatile and transient keywords

1) transient keyword is used along with instance variables to exclude them from serialization process. If a field is transient its value will not be persisted.

On the other hand, volatile keyword is used to mark a Java variable as "being stored in main memory".

Every read of a volatile variable will be read from the computer's main memory, and not from the CPU cache, and that every write to a volatile variable will be written to main memory, and not just to the CPU cache.

2) transient keyword cannot be used along with static keyword but volatile can be used along with static.

3) transient variables are initialized with default value during de-serialization and there assignment or restoration of value has to be handled by application code.

For more information, see my blog:
http://javaexplorer03.blogspot.in/2015/07/difference-between-volatile-and.html

Lodash .clone and .cloneDeep behaviors

Thanks to Gruff Bunny and Louis' comments, I found the source of the issue.

As I use Backbone.js too, I loaded a special build of Lodash compatible with Backbone and Underscore that disables some features. In this example:

var clone = _.clone(data, true);

data[1].values.d = 'x';

I just replaced the Underscore build with the Normal build in my Backbone application and the application is still working. So I can now use the Lodash .clone with the expected behaviour.

Edit 2018: the Underscore build doesn't seem to exist anymore. If you are reading this in 2018, you could be interested by this documentation (Backbone and Lodash).

How can I count the occurrences of a string within a file?

This will output the number of lines that contain your search string.

grep -c "echo" FILE

This won't, however, count the number of occurrences in the file (ie, if you have echo multiple times on one line).

edit:

After playing around a bit, you could get the number of occurrences using this dirty little bit of code:

sed 's/echo/echo\n/g' FILE | grep -c "echo"

This basically adds a newline following every instance of echo so they're each on their own line, allowing grep to count those lines. You can refine the regex if you only want the word "echo", as opposed to "echoing", for example.

Laravel Password & Password_Confirmation Validation

You can use the confirmed validation rule.

$this->validate($request, [
    'name' => 'required|min:3|max:50',
    'email' => 'email',
    'vat_number' => 'max:13',
    'password' => 'required|confirmed|min:6',
]);

Converting a String to DateTime

Nobody seems to implemented an extension method. With the help of @CMS's answer:

Working and improved full source example is here: Gist Link

namespace ExtensionMethods {
    using System;
    using System.Globalization;

    public static class DateTimeExtensions {
        public static DateTime ToDateTime(this string s, 
                  string format = "ddMMyyyy", string cultureString = "tr-TR") {
            try {
                var r = DateTime.ParseExact(
                    s: s,
                    format: format,
                    provider: CultureInfo.GetCultureInfo(cultureString));
                return r;
            } catch (FormatException) {
                throw;
            } catch (CultureNotFoundException) {
                throw; // Given Culture is not supported culture
            }
        }

        public static DateTime ToDateTime(this string s, 
                    string format, CultureInfo culture) {
            try {
                var r = DateTime.ParseExact(s: s, format: format, 
                                        provider: culture);
                return r;
            } catch (FormatException) {
                throw;
            } catch (CultureNotFoundException) {
                throw; // Given Culture is not supported culture
            }

        }

    }
}

namespace SO {
    using ExtensionMethods;
    using System;
    using System.Globalization;

    class Program {
        static void Main(string[] args) {
            var mydate = "29021996";
            var date = mydate.ToDateTime(format: "ddMMyyyy"); // {29.02.1996 00:00:00}

            mydate = "2016 3";
            date = mydate.ToDateTime("yyyy M"); // {01.03.2016 00:00:00}

            mydate = "2016 12";
            date = mydate.ToDateTime("yyyy d"); // {12.01.2016 00:00:00}

            mydate = "2016/31/05 13:33";
            date = mydate.ToDateTime("yyyy/d/M HH:mm"); // {31.05.2016 13:33:00}

            mydate = "2016/31 Ocak";
            date = mydate.ToDateTime("yyyy/d MMMM"); // {31.01.2016 00:00:00}

            mydate = "2016/31 January";
            date = mydate.ToDateTime("yyyy/d MMMM", cultureString: "en-US"); 
            // {31.01.2016 00:00:00}

            mydate = "11/?????/1437";
            date = mydate.ToDateTime(
                culture: CultureInfo.GetCultureInfo("ar-SA"),
                format: "dd/MMMM/yyyy"); 
         // Weird :) I supposed dd/yyyy/MMMM but that did not work !?$^&*

            System.Diagnostics.Debug.Assert(
               date.Equals(new DateTime(year: 2016, month: 5, day: 18)));
        }
    }
}

Month name as a string

Use this :

Calendar cal=Calendar.getInstance();
SimpleDateFormat month_date = new SimpleDateFormat("MMMM");
String month_name = month_date.format(cal.getTime());

Month name will contain the full month name,,if you want short month name use this

 SimpleDateFormat month_date = new SimpleDateFormat("MMM");
 String month_name = month_date.format(cal.getTime());

Eclipse: All my projects disappeared from Project Explorer

Today 22-03-2016, I check again this question and using ECLIPSE MARS I solved with:

  • Having Eclipse opened, go on FILE -> RESTART

Go on same workspace and I have all project on "PROJECT EXPLORER"

Sometime also this operation, will solve (Clicking on Projects dor see all project!!)

 my problem

So Other solution is:

SOLUTION

Where is the php.ini file on a Linux/CentOS PC?

In your terminal/console (only Linux, in windows you need Putty)

ssh user@ip
php -i | grep "Loaded Configuration File"

And it will show you something like this Loaded Configuration File => /etc/php.ini.

ALTERNATIVE METHOD

You can make a php file on your website, which run: <?php phpinfo(); ?>, and you can see the php.ini location on the line with: "Loaded Configuration File".

Update This command gives the path right away

cli_php_ini=php -i | grep /.+/php.ini -oE  #ref. https://stackoverflow.com/a/15763333/248616
    php_ini="${cli_php_ini/cli/apache2}"   #replace cli by apache2 ref. https://stackoverflow.com/a/13210909/248616

How to run DOS/CMD/Command Prompt commands from VB.NET?

You Can try This To Run Command Then cmd Exits

Process.Start("cmd", "/c YourCode")

You Can try This To Run The Command And Let cmd Wait For More Commands

Process.Start("cmd", "/k YourCode")

What happened to the .pull-left and .pull-right classes in Bootstrap 4?

Back in 2016 when this question was originally asked, the answer was:

$('.pull-right').addClass('pull-xs-right').removeClass('pull-right')

But now the accepted answer should be Robert Went's.

Changing the row height of a datagridview

you can do that on RowAdded Event :

_data_grid_view.RowsAdded += new System.Windows.Forms.DataGridViewRowsAddedEventHandler(this._data_grid_view_RowsAdded);

private void _data_grid_view_RowsAdded(object sender, DataGridViewRowsAddedEventArgs e)
        {
            _data_grid_view.Rows[e.RowIndex].Height = 42;
        }

when a row add to the dataGridView it just change it height to 42.

javac option to compile all java files under a given directory recursively

javac command does not follow a recursive compilation process, so you have either specify each directory when running command, or provide a text file with directories you want to include:

javac -classpath "${CLASSPATH}" @java_sources.txt

Where to find 64 bit version of chromedriver.exe for Selenium WebDriver?

In the below mentioned link, ChromeDriver.exe for Windows 32 bit exist.

http://chromedriver.storage.googleapis.com/index.html?path=2.24/

It is working for me in Win7 64 bit.

Multiple WHERE Clauses with LINQ extension methods

you can use && and write all conditions in to the same where clause, or you can .Where().Where().Where()... and so on.

How to set cornerRadius for only top-left and top-right corner of a UIView?

Here is a short method implemented like this:

- (void)viewDidLoad {
    [super viewDidLoad];
    UIButton *openInMaps = [UIButton new];
    [openInMaps setFrame:CGRectMake(15, 135, 114, 70)];
    openInMaps = (UIButton *)[self roundCornersOnView:openInMaps onTopLeft:NO topRight:NO bottomLeft:YES bottomRight:NO radius:5.0];
}

- (UIView *)roundCornersOnView:(UIView *)view onTopLeft:(BOOL)tl topRight:(BOOL)tr bottomLeft:(BOOL)bl bottomRight:(BOOL)br radius:(float)radius {

    if (tl || tr || bl || br) {
        UIRectCorner corner = 0;
        if (tl) {corner = corner | UIRectCornerTopLeft;}
        if (tr) {corner = corner | UIRectCornerTopRight;}
        if (bl) {corner = corner | UIRectCornerBottomLeft;}
        if (br) {corner = corner | UIRectCornerBottomRight;}

        UIView *roundedView = view;
        UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:roundedView.bounds byRoundingCorners:corner cornerRadii:CGSizeMake(radius, radius)];
        CAShapeLayer *maskLayer = [CAShapeLayer layer];
        maskLayer.frame = roundedView.bounds;
        maskLayer.path = maskPath.CGPath;
        roundedView.layer.mask = maskLayer;
        return roundedView;
    }
    return view;
}

"The public type <<classname>> must be defined in its own file" error in Eclipse

You can't use 2 public class instances, you need to use one. Try using class (name) instead of public class (name)

How to multiply individual elements of a list with a number?

You can use built-in map function:

result = map(lambda x: x * P, S)

or list comprehensions that is a bit more pythonic:

result = [x * P for x in S]

Use Expect in a Bash script to provide a password to an SSH command

Mixing Bash and Expect is not a good way to achieve the desired effect. I'd try to use only Expect:

#!/usr/bin/expect
eval spawn ssh -oStrictHostKeyChecking=no -oCheckHostIP=no usr@$myhost.example.com

# Use the correct prompt
set prompt ":|#|\\\$"
interact -o -nobuffer -re $prompt return
send "my_password\r"
interact -o -nobuffer -re $prompt return
send "my_command1\r"
interact -o -nobuffer -re $prompt return
send "my_command2\r"
interact

Sample solution for bash could be:

#!/bin/bash
/usr/bin/expect -c 'expect "\n" { eval spawn ssh -oStrictHostKeyChecking=no -oCheckHostIP=no usr@$myhost.example.com; interact }'

This will wait for Enter and then return to (for a moment) the interactive session.

SVG drop shadow using css3

Probably an evolution, it appears that inline css filters works nicely on elements, in a certain way.

Declaring a drop-shadow css filter, in an svg element, in both a class or inline does NOT works, as specified earlier.

But, at least in Firefox, with the following wizardry:

Appending the filter declaration inline, with javascript, after DOM load.

_x000D_
_x000D_
// Does not works, with regular dynamic css styling:

shadow0.oninput = () => {
  rect1.style.filter = "filter:drop-shadow(0 0 " + shadow0.value + "rem black);"
}

// Okay! Inline styling, appending.

shadow1.oninput = () => {
  rect1.style += " ;filter:drop-shadow(0 0 " + shadow1.value + "rem black);"
  rect2.style += " ;filter:drop-shadow(0 0 " + shadow1.value + "rem black);"
}
_x000D_
<h2>Firefox only</h2>
<h4>
Does not works! 
<input id="shadow0" type="number" min="0" max="100" step="0.1">

 | Okay!
<input id="shadow1" type="number" min="0" max="100" step="0.1">

<svg viewBox="0 0 120 70">  
    <rect id="rect1" x="10" y="10" width="100" height="50" fill="#c66" />
    
    <!-- Inline style declaration does NOT works at svg level, no shadow at loading: -->
    <rect id="rect2" x="40" y="30" width="10" height="10" fill="#aaa" style="filter:drop-shadow(0 0 20rem black)" />
    
</svg>
_x000D_
_x000D_
_x000D_

enter image description here

Intersect Two Lists in C#

public static List<T> ListCompare<T>(List<T> List1 , List<T> List2 , string key )
{
    return List1.Select(t => t.GetType().GetProperty(key).GetValue(t))
                .Intersect(List2.Select(t => t.GetType().GetProperty(key).GetValue(t))).ToList();
}

Run an exe from C# code

I know this is well answered, but if you're interested, I wrote a library that makes executing commands much easier.

Check it out here: https://github.com/twitchax/Sheller.

How to check if a value exists in an object using JavaScript

I did a test with all these examples, and I ran this in Node.js v8.11.2. Take this as a guide to select your best choice.

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let i, tt;
    const obj = { a: 'test1', b: 'test2', c: 'test3', d: 'test4', e: 'test5', f: 'test6' };

console.time("test1")
i = 0;
for( ; i<1000000; i=i+1) {
  if (Object.values(obj).indexOf('test4') > -1) {
    tt = true;
  }
}
console.timeEnd("test1")

console.time("test1.1")
i = 0;
for( ; i<1000000 ; i=i+1) {
  if (~Object.values(obj).indexOf('test4')) {
    tt = true;
  }
}
console.timeEnd("test1.1")

console.time("test2")
i = 0;
for( ; i<1000000; i=i+1) {
  if (Object.values(obj).includes('test4')) {
    tt = true;
  }
}
console.timeEnd("test2")


console.time("test3")
i = 0;
for( ; i<1000000 ; i=i+1) {
  for(const item in obj) {
    if(obj[item] == 'test4') {
      tt = true;
      break;
    }
  }
}
console.timeEnd("test3")

console.time("test3.1")
i = 0;
for( ; i<1000000; i=i+1) {
  for(const [item, value] in obj) {
    if(value == 'test4') {
      tt = true;
      break;
    }
  }
}
console.timeEnd("test3.1")


console.time("test4")
i = 0;
for( ; i<1000000; i=i+1) {
  tt = Object.values(obj).some((val, val2) => {
    return val == "test4"
  });
}
console.timeEnd("test4")

console.time("test5")
i = 0;
for( ; i<1000000; i=i+1) {
  const arr = Object.keys(obj);
  const len = arr.length;
  let i2 = 0;
  for( ; i2<len ; i2=i2+1) {
    if(obj[arr[i2]] == "test4") {
      tt = true;
      break;
    }
  }
}
console.timeEnd("test5")
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Output on my server

test1:   272.325 ms
test1.1: 246.316 ms
test2:   251.98 0ms
test3:    73.284 ms
test3.1: 102.029 ms
test4:   339.299 ms
test5:    85.527 ms

Polymorphism: Why use "List list = new ArrayList" instead of "ArrayList list = new ArrayList"?

I think @tsatiz's answer is mostly right (programming to an interface rather than an implementation). However, by programming to the interface you won't lose any functionality. Let me explain.

If you declare your variable as a List<type> list = new ArrayList<type> you do not actually lose any functionality of the ArrayList. All you need to do is to cast your list down to an ArrayList. Here's an example:

List<String> list = new ArrayList<String>();
((ArrayList<String>) list).ensureCapacity(19);

Ultimately I think tsatiz is correct as once you cast to an ArrayList you're no longer coding to an interface. However, it's still a good practice to initially code to an interface and, if it later becomes necessary, code to an implementation if you must.

Hope that helps!

Single Line Nested For Loops

Below code for best examples for nested loops, while using two for loops please remember the output of the first loop is input for the second loop. Loop termination also important while using the nested loops

for x in range(1, 10, 1):
     for y in range(1,x):
             print y,
        print
OutPut :
1
1 2
1 2 3
1 2 3 4
1 2 3 4 5
1 2 3 4 5 6
1 2 3 4 5 6 7
1 2 3 4 5 6 7 8

Which rows are returned when using LIMIT with OFFSET in MySQL?

It will return 18 results starting on record #9 and finishing on record #26.

Start by reading the query from offset. First you offset by 8, which means you skip the first 8 results of the query. Then you limit by 18. Which means you consider records 9, 10, 11, 12, 13, 14, 15, 16....24, 25, 26 which are a total of 18 records.

Check this out.

And also the official documentation.

MySQL my.cnf performance tuning recommendations

Try starting with the Percona wizard and comparing their recommendations against your current settings one by one. Don't worry there aren't as many applicable settings as you might think.

https://tools.percona.com/wizard

Update circa 2020: Sorry, this tool reached it's end of life: https://www.percona.com/blog/2019/04/22/end-of-life-query-analyzer-and-mysql-configuration-generator/

Everyone points to key_buffer_size first which you have addressed. With 96GB memory I'd be wary of any tiny default value (likely to be only 96M!).

Stripping everything but alphanumeric chars from a string in Python

I just timed some functions out of curiosity. In these tests I'm removing non-alphanumeric characters from the string string.printable (part of the built-in string module). The use of compiled '[\W_]+' and pattern.sub('', str) was found to be fastest.

$ python -m timeit -s \
     "import string" \
     "''.join(ch for ch in string.printable if ch.isalnum())" 
10000 loops, best of 3: 57.6 usec per loop

$ python -m timeit -s \
    "import string" \
    "filter(str.isalnum, string.printable)"                 
10000 loops, best of 3: 37.9 usec per loop

$ python -m timeit -s \
    "import re, string" \
    "re.sub('[\W_]', '', string.printable)"
10000 loops, best of 3: 27.5 usec per loop

$ python -m timeit -s \
    "import re, string" \
    "re.sub('[\W_]+', '', string.printable)"                
100000 loops, best of 3: 15 usec per loop

$ python -m timeit -s \
    "import re, string; pattern = re.compile('[\W_]+')" \
    "pattern.sub('', string.printable)" 
100000 loops, best of 3: 11.2 usec per loop

PHP error: "The zip extension and unzip command are both missing, skipping."

On docker with image php:7.2-apache I just needed zip and unzip. No need for php-zip :

apt-get install zip unzip

or Dockerfile

RUN ["apt-get", "update"]
RUN ["apt-get", "install", "-y", "zip"]
RUN ["apt-get", "install", "-y", "unzip"]

Fill Combobox from database

string query = "SELECT column_name FROM table_name";      //query the database
SqlCommand queryStatus = new SqlCommand(query, myConnection);
sqlDataReader reader = queryStatus.ExecuteReader();                               
            
while (reader.Read())   //loop reader and fill the combobox
{
ComboBox1.Items.Add(reader["column_name"].ToString());
}

How to print the full NumPy array, without truncation?

The previous answers are the correct ones, but as a weaker alternative you can transform into a list:

>>> numpy.arange(100).reshape(25,4).tolist()

[[0, 1, 2, 3], [4, 5, 6, 7], [8, 9, 10, 11], [12, 13, 14, 15], [16, 17, 18, 19], [20, 21,
22, 23], [24, 25, 26, 27], [28, 29, 30, 31], [32, 33, 34, 35], [36, 37, 38, 39], [40, 41,
42, 43], [44, 45, 46, 47], [48, 49, 50, 51], [52, 53, 54, 55], [56, 57, 58, 59], [60, 61,
62, 63], [64, 65, 66, 67], [68, 69, 70, 71], [72, 73, 74, 75], [76, 77, 78, 79], [80, 81,
82, 83], [84, 85, 86, 87], [88, 89, 90, 91], [92, 93, 94, 95], [96, 97, 98, 99]]

How to select a node of treeview programmatically in c#?

TreeViewItem tempItem = new TreeViewItem();
TreeViewItem tempItem1 = new TreeViewItem(); 
tempItem =  (TreeViewItem) treeView1.Items.GetItemAt(0);    // Selecting the first of the top level nodes
tempItem1 = (TreeViewItem)tempItem.Items.GetItemAt(0);      // Selecting the first child of the first first level node
SelectedCategoryHeaderString = tempItem.Header.ToString();  // gets the header for the first top level node
SelectedCategoryHeaderString = tempItem1.Header.ToString(); // gets the header for the first child node of the first top level node
tempItem.IsExpanded = true;         //  will expand the first node

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured

It's happening because the @valerio-vaudi said.

Your problem is the dependency of spring batch spring-boot-starter-batch that has a spring-boot-starter-jdbc transitive maven dependency.

But you can resolve it set the primary datasource with your configuration

 @Primary
 @Bean(name = "dataSource")
 @ConfigurationProperties(prefix = "spring.datasource")
 public DataSource getDataSource() {
      return DataSourceBuilder.create().build();
 }

 @Bean
 public JdbcTemplate jdbcTemplate(DataSource dataSource) {
      return new JdbcTemplate(dataSource);
 }

Converting a Java Keystore into PEM Format

The keytool command will not allow you to export the private key from a key store. You have to write some Java code to do this. Open the key store, get the key you need, and save it to a file in PKCS #8 format. Save the associated certificate too.

KeyStore ks = KeyStore.getInstance("jks");
/* Load the key store. */
...
char[] password = ...;
/* Save the private key. */
FileOutputStream kos = new FileOutputStream("tmpkey.der");
Key pvt = ks.getKey("your_alias", password);
kos.write(pvt.getEncoded());
kos.flush();
kos.close();
/* Save the certificate. */
FileOutputStream cos = new FileOutputStream("tmpcert.der");
Certificate pub = ks.getCertificate("your_alias");
cos.write(pub.getEncoded());
cos.flush();
cos.close();

Use OpenSSL utilities to convert these files (which are in binary format) to PEM format.

openssl pkcs8 -inform der -nocrypt < tmpkey.der > tmpkey.pem
openssl x509 -inform der < tmpcert.der > tmpcert.pem

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

Summary: to get physical CPUs do this:

grep 'core id' /proc/cpuinfo | sort -u

to get physical and logical CPUs do this:

grep -c ^processor /proc/cpuinfo

/proc << this is the golden source of any info you need about processes and

/proc/cpuinfo << is the golden source of any CPU information.

Convert java.util.date default format to Timestamp in Java

Best one

String str_date=month+"-"+day+"-"+yr;
DateFormat formatter = new SimpleDateFormat("MM-dd-yyyy");
Date date = (Date)formatter.parse(str_date); 
long output=date.getTime()/1000L;
String str=Long.toString(output);
long timestamp = Long.parseLong(str) * 1000;

Bootstrap carousel width and height

I have created a responsive sample that works well for me and I find it to be quite simple have a look at my carousel-fill:

.carousel-fill {
    height: -o-calc(100vh - 165px) !important;
    height: -webkit-calc(100vh - 165px) !important;
    height: -moz-calc(100vh - 165px) !important;
    height: calc(100vh - 165px) !important;
    width: auto !important;
    overflow: hidden;
    display: inline-block;
    text-align: center;
}

.carousel-item {
    text-align: center !important;
}

my navigation height+footer are a hair less then 165px so that value works for me. take off a value that fits for you, I overrdide the .carousel-item from bootstrap so make sure by videos are centered.

my carousel looks like this, note the "carousel-fill" on the video tag.

<div>
        <div id="myCarousel" class="carousel slide carousel-fade text-center" data-ride="carousel">
            <!-- Indicators -->
            <ol class="carousel-indicators">
                <li data-target="#myCarousel" data-slide-to="0" class="active"></li>
                <li data-target="#myCarousel" data-slide-to="1"></li>
                <li data-target="#myCarousel" data-slide-to="2"></li>
                <li data-target="#myCarousel" data-slide-to="3"></li>
            </ol>

            <!-- Wrapper for slides -->
            <div class="carousel-inner">
                <div class="carousel-item active">
                    <video autoplay muted class="carousel-fill">
                        <source src="~/Video/CATSTrade.mp4" type="video/mp4">
                        Your browser does not support the video tag.
                    </video>
                    <div class="carousel-caption">
                        <h2>CATS IV Trade engine</h2>
                        <p>Automated trading for high ROI</p>
                    </div>
                </div>
                <div class="carousel-item">
                    <video muted loop class="carousel-fill">
                        <source src="~/Video/itrs.mp4" type="video/mp4">
                    </video>
                    <div class="carousel-caption">
                        <h2>Machine learning</h2>
                        <p>Machine learning specialist</p>
                    </div>
                </div>
                <div class="carousel-item">
                    <video muted loop class="carousel-fill">
                        <source src="~/Video/frequency.mp4" type="video/mp4">
                    </video>
                    <div class="carousel-caption">
                        <h3>Low latency development</h3>
                        <p>Create ultra fast systems with our consultants</p>
                    </div>
                </div>
                <div class="carousel-item">
                    <img src="~/Images/data pipeline faded.png" class="carousel-fill" />

                    <div class="carousel-caption">
                        <h3>Big Data</h3>
                        <p>Maintain, generate, and host big data</p>
                    </div>
                </div>
            </div>

            <!-- Left and right controls -->
            <a class="carousel-control-prev" href="#myCarousel" data-slide="prev">
                <span class="carousel-control-prev-icon" aria-hidden="true"></span>
                <span class="sr-only">Previous</span>
            </a>
            <a class="carousel-control-next" href="#myCarousel" data-slide="next">
                <span class="carousel-control-next-icon" aria-hidden="true"></span>
                <span class="sr-only">Next</span>
            </a>
        </div>
    </div>

in case some one needs to control the videos like i do, I start and stop the videos like this:

<script language="JavaScript" type="text/javascript">
        $(document).ready(function () {
            $('.carousel').carousel({ interval: 8000 })
            $('#myCarousel').on('slide.bs.carousel', function (args) {
                var videoList = document.getElementsByTagName("video");
                switch (args.from) {
                    case 0:
                        videoList[0].pause();
                        break;
                    case 1:
                        videoList[1].pause();
                        break;
                    case 2:
                        videoList[2].pause();
                        break;
                }
                switch (args.to) {
                    case 0:
                        videoList[0].play();

                        break;
                    case 1:
                        videoList[1].play();
                        break;
                    case 2:
                        videoList[2].play();
                        break;
                }
            })

        });
</script>

Can you have multiline HTML5 placeholder text in a <textarea>?

This can apparently be done by just typing normally,

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<textarea name="" id="" placeholder="Hello awesome world. I will break line now

Yup! Line break seems to work."></textarea>
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When is each sorting algorithm used?

The Wikipedia page on sorting algorithms has a great comparison chart.

http://en.wikipedia.org/wiki/Sorting_algorithm#Comparison_of_algorithms

C - freeing structs

free is not enough, free just marks the memory as unused, the struct data will be there until overwriting. For safety, set the pointer to NULL after free.

Ex:

if (testPerson) {
    free(testPerson);
    testPerson = NULL;
}

struct is similar like an array, it is a block of memory. You can access to struct member via its offset. The first struct's member is placed at offset 0 so the address of first struct's member is same as the address of struct.

How to use Select2 with JSON via Ajax request?

This is how I fixed my issue, I am getting data in data variable and by using above solutions I was getting error could not load results. I had to parse the results differently in processResults.

searchBar.select2({
            ajax: {
                url: "/search/live/results/",
                dataType: 'json',
                headers : {'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')},
                delay: 250,
                type: 'GET',
                data: function (params) {
                    return {
                        q: params.term, // search term
                    };
                },
                processResults: function (data) {
                    var arr = []
                    $.each(data, function (index, value) {
                        arr.push({
                            id: index,
                            text: value
                        })
                    })
                    return {
                        results: arr
                    };
                },
                cache: true
            },
            escapeMarkup: function (markup) { return markup; },
            minimumInputLength: 1
        });

How to get just one file from another branch

Or if you want all the files from another branch:

git checkout <branch name> -- .

Get current value when change select option - Angular2

There is a way to get the value from different options. check this plunker

component.html

<select class="form-control" #t (change)="callType(t.value)">
  <option *ngFor="#type of types" [value]="type">{{type}}</option>
</select>

component.ts

this.types = [ 'type1', 'type2', 'type3' ];

callType(value) {
  console.log(value);
  this.order.type = value;
}

HttpClient - A task was cancelled?

In my situation, the controller method was not made as async and the method called inside the controller method was async.

So I guess its important to use async/await all the way to top level to avoid issues like these.

Laravel Check If Related Model Exists

A Relation object passes unknown method calls through to an Eloquent query Builder, which is set up to only select the related objects. That Builder in turn passes unknown method calls through to its underlying query Builder.

This means you can use the exists() or count() methods directly from a relation object:

$model->relation()->exists(); // bool: true if there is at least one row
$model->relation()->count(); // int: number of related rows

Note the parentheses after relation: ->relation() is a function call (getting the relation object), as opposed to ->relation which a magic property getter set up for you by Laravel (getting the related object/objects).

Using the count method on the relation object (that is, using the parentheses) will be much faster than doing $model->relation->count() or count($model->relation) (unless the relation has already been eager-loaded) since it runs a count query rather than pulling all of the data for any related objects from the database, just to count them. Likewise, using exists doesn't need to pull model data either.

Both exists() and count() work on all relation types I've tried, so at least belongsTo, hasOne, hasMany, and belongsToMany.

How to deal with http status codes other than 200 in Angular 2

Yes you can handle with the catch operator like this and show alert as you want but firstly you have to import Rxjs for the same like this way

import {Observable} from 'rxjs/Rx';

return this.http.request(new Request(this.requestoptions))
            .map((res: Response) => {
                if (res) {
                    if (res.status === 201) {
                        return [{ status: res.status, json: res }]
                    }
                    else if (res.status === 200) {
                        return [{ status: res.status, json: res }]
                    }
                }
            }).catch((error: any) => {
                if (error.status === 500) {
                    return Observable.throw(new Error(error.status));
                }
                else if (error.status === 400) {
                    return Observable.throw(new Error(error.status));
                }
                else if (error.status === 409) {
                    return Observable.throw(new Error(error.status));
                }
                else if (error.status === 406) {
                    return Observable.throw(new Error(error.status));
                }
            });
    }

also you can handel error (with err block) that is throw by catch block while .map function,

like this -

...
.subscribe(res=>{....}
           err => {//handel here});

Update

as required for any status without checking particluar one you can try this: -

return this.http.request(new Request(this.requestoptions))
            .map((res: Response) => {
                if (res) {
                    if (res.status === 201) {
                        return [{ status: res.status, json: res }]
                    }
                    else if (res.status === 200) {
                        return [{ status: res.status, json: res }]
                    }
                }
            }).catch((error: any) => {
                if (error.status < 400 ||  error.status ===500) {
                    return Observable.throw(new Error(error.status));
                }
            })
            .subscribe(res => {...},
                       err => {console.log(err)} );

Detecting arrow key presses in JavaScript

Here's how I did it:

var leftKey = 37, upKey = 38, rightKey = 39, downKey = 40;
var keystate;
document.addEventListener("keydown", function (e) {
    keystate[e.keyCode] = true;
});
document.addEventListener("keyup", function (e) {
    delete keystate[e.keyCode];
});

if (keystate[leftKey]) {
//code to be executed when left arrow key is pushed.
}
if (keystate[upKey]) {
//code to be executed when up arrow key is pushed.
}
if (keystate[rightKey]) {
//code to be executed when right arrow key is pushed.
}
if (keystate[downKey]) {
//code to be executed when down arrow key is pushed.
}

How to add conditional attribute in Angular 2?

in angular-2 attribute syntax is

<div [attr.role]="myAriaRole">

Binds attribute role to the result of expression myAriaRole.

so can use like

[attr.role]="myAriaRole ? true: null"

How to save a pandas DataFrame table as a png

The following would need extensive customisation to format the table correctly, but the bones of it works:

import numpy as np
from PIL import Image, ImageDraw, ImageFont
import pandas as pd

df = pd.DataFrame({ 'A' : 1.,
                     'B' : pd.Series(1,index=list(range(4)),dtype='float32'),
                     'C' : np.array([3] * 4,dtype='int32'),
                     'D' : pd.Categorical(["test","train","test","train"]),
                     'E' : 'foo' })


class DrawTable():
    def __init__(self,_df):
        self.rows,self.cols = _df.shape
        img_size = (300,200)
        self.border = 50
        self.bg_col = (255,255,255)
        self.div_w = 1
        self.div_col = (128,128,128)
        self.head_w = 2
        self.head_col = (0,0,0)
        self.image = Image.new("RGBA", img_size,self.bg_col)
        self.draw = ImageDraw.Draw(self.image)
        self.draw_grid()
        self.populate(_df)
        self.image.show()
    def draw_grid(self):
        width,height = self.image.size
        row_step = (height-self.border*2)/(self.rows)
        col_step = (width-self.border*2)/(self.cols)
        for row in range(1,self.rows+1):
            self.draw.line((self.border-row_step//2,self.border+row_step*row,width-self.border,self.border+row_step*row),fill=self.div_col,width=self.div_w)
            for col in range(1,self.cols+1):
                self.draw.line((self.border+col_step*col,self.border-col_step//2,self.border+col_step*col,height-self.border),fill=self.div_col,width=self.div_w)
        self.draw.line((self.border-row_step//2,self.border,width-self.border,self.border),fill=self.head_col,width=self.head_w)
        self.draw.line((self.border,self.border-col_step//2,self.border,height-self.border),fill=self.head_col,width=self.head_w)
        self.row_step = row_step
        self.col_step = col_step
    def populate(self,_df2):
        font = ImageFont.load_default().font
        for row in range(self.rows):
            print(_df2.iloc[row,0])
            self.draw.text((self.border-self.row_step//2,self.border+self.row_step*row),str(_df2.index[row]),font=font,fill=(0,0,128))
            for col in range(self.cols):
                text = str(_df2.iloc[row,col])
                text_w, text_h = font.getsize(text)
                x_pos = self.border+self.col_step*(col+1)-text_w
                y_pos = self.border+self.row_step*row
                self.draw.text((x_pos,y_pos),text,font=font,fill=(0,0,128))
        for col in range(self.cols):
            text = str(_df2.columns[col])
            text_w, text_h = font.getsize(text)
            x_pos = self.border+self.col_step*(col+1)-text_w
            y_pos = self.border - self.row_step//2
            self.draw.text((x_pos,y_pos),text,font=font,fill=(0,0,128))
    def save(self,filename):
        try:
            self.image.save(filename,mode='RGBA')
            print(filename," Saved.")
        except:
            print("Error saving:",filename)




table1 = DrawTable(df)
table1.save('C:/Users/user/Pictures/table1.png')

The output looks like this:

enter image description here

Extracting extension from filename in Python

For simple use cases one option may be splitting from dot:

>>> filename = "example.jpeg"
>>> filename.split(".")[-1]
'jpeg'

No error when file doesn't have an extension:

>>> "filename".split(".")[-1]
'filename'

But you must be careful:

>>> "png".split(".")[-1]
'png'    # But file doesn't have an extension

Also will not work with hidden files in Unix systems:

>>> ".bashrc".split(".")[-1]
'bashrc'    # But this is not an extension

For general use, prefer os.path.splitext

WPF Timer Like C# Timer

The usual WPF timer is the DispatcherTimer, which is not a control but used in code. It basically works the same way like the WinForms timer:

System.Windows.Threading.DispatcherTimer dispatcherTimer = new System.Windows.Threading.DispatcherTimer();
dispatcherTimer.Tick += dispatcherTimer_Tick;
dispatcherTimer.Interval = new TimeSpan(0,0,1);
dispatcherTimer.Start();


private void dispatcherTimer_Tick(object sender, EventArgs e)
{
  // code goes here
}

More on the DispatcherTimer can be found here

Multiple lines of input in <input type="text" />

Use the textarea

<textarea name="textarea" style="width:250px;height:150px;"></textarea>

don't leave any space between the opening and closing tags Or Else This will leave some empty lines or spaces.

Why does datetime.datetime.utcnow() not contain timezone information?

Note that for Python 3.2 onwards, the datetime module contains datetime.timezone. The documentation for datetime.utcnow() says:

An aware current UTC datetime can be obtained by calling datetime.now(timezone.utc).

So, datetime.utcnow() doesn't set tzinfo to indicate that it is UTC, but datetime.now(datetime.timezone.utc) does return UTC time with tzinfo set.

So you can do:

>>> import datetime
>>> datetime.datetime.now(datetime.timezone.utc)
datetime.datetime(2014, 7, 10, 2, 43, 55, 230107, tzinfo=datetime.timezone.utc)

XDocument or XmlDocument

As mentioned elsewhere, undoubtedly, Linq to Xml makes creation and alteration of xml documents a breeze in comparison to XmlDocument, and the XNamespace ns + "elementName" syntax makes for pleasurable reading when dealing with namespaces.

One thing worth mentioning for xsl and xpath die hards to note is that it IS possible to still execute arbitrary xpath 1.0 expressions on Linq 2 Xml XNodes by including:

using System.Xml.XPath;

and then we can navigate and project data using xpath via these extension methods:

For instance, given the Xml document:

<xml>
    <foo>
        <baz id="1">10</baz>
        <bar id="2" special="1">baa baa</bar>
        <baz id="3">20</baz>
        <bar id="4" />
        <bar id="5" />
    </foo>
    <foo id="123">Text 1<moo />Text 2
    </foo>
</xml>

We can evaluate:

var node = xele.XPathSelectElement("/xml/foo[@id='123']");
var nodes = xele.XPathSelectElements(
"//moo/ancestor::xml/descendant::baz[@id='1']/following-sibling::bar[not(@special='1')]");
var sum = xele.XPathEvaluate("sum(//foo[not(moo)]/baz)");

Why does MSBuild look in C:\ for Microsoft.Cpp.Default.props instead of c:\Program Files (x86)\MSBuild? ( error MSB4019)

I just added VCTargetsPath={c:\...} as an environment variable to my Hudson job.

Python JSON serialize a Decimal object

In my Flask app, Which uses python 2.7.11, flask alchemy(with 'db.decimal' types), and Flask Marshmallow ( for 'instant' serializer and deserializer), i had this error, every time i did a GET or POST. The serializer and deserializer, failed to convert Decimal types into any JSON identifiable format.

I did a "pip install simplejson", then Just by adding

import simplejson as json

the serializer and deserializer starts to purr again. I did nothing else... DEciamls are displayed as '234.00' float format.

Javascript Thousand Separator / string format

Update (7 years later)

The reference cited in the original answer below was wrong. There is a built in function for this, which is exactly what kaiser suggests below: toLocaleString

So you can do:

(1234567.89).toLocaleString('en')              // for numeric input
parseFloat("1234567.89").toLocaleString('en')  // for string input

The function implemented below works, too, but simply isn't necessary.

(I thought perhaps I'd get lucky and find out that it was necessary back in 2010, but no. According to this more reliable reference, toLocaleString has been part of the standard since ECMAScript 3rd Edition [1999], which I believe means it would have been supported as far back as IE 5.5.)


Original Answer

According to this reference there isn't a built in function for adding commas to a number. But that page includes an example of how to code it yourself:

function addCommas(nStr) {
    nStr += '';
    var x = nStr.split('.');
    var x1 = x[0];
    var x2 = x.length > 1 ? '.' + x[1] : '';
    var rgx = /(\d+)(\d{3})/;
    while (rgx.test(x1)) {
            x1 = x1.replace(rgx, '$1' + ',' + '$2');
    }
    return x1 + x2;
}

Edit: To go the other way (convert string with commas to number), you could do something like this:

parseFloat("1,234,567.89".replace(/,/g,''))

deny directory listing with htaccess

For showing Forbidden error then include these lines in your .htaccess file:

Options -Indexes 

If we want to index our files and showing them with some information, then use:

IndexOptions -FancyIndexing

If we want for some particular extension not to show, then:

IndexIgnore *.zip *.css

How to iterate through range of Dates in Java?

You can try this:

OffsetDateTime currentDateTime = OffsetDateTime.now();
for (OffsetDateTime date = currentDateTime; date.isAfter(currentDateTime.minusYears(YEARS)); date = date.minusWeeks(1))
{
    ...
}

installing vmware tools: location of GCC binary?

First execute this

sudo apt-get install gcc binutils make linux-source

Then run again

/usr/bin/vmware-config-tools.pl

This is all you need to do. Now your system has the gcc make and the linux kernel sources.

convert HTML ( having Javascript ) to PDF using JavaScript

Copy and paste this in your site to provide a link which will convert the page to a PDF page.

<a href="javascript:void(window.open('http://www.htmltopdfconverter.net/?convert='+window.location))">Convert To PDF</a>

Regular vs Context Free Grammars

Regular grammar is either right or left linear, whereas context free grammar is basically any combination of terminals and non-terminals. Hence you can see that regular grammar is a subset of context-free grammar.

So for a palindrome for instance, is of the form,

S->ABA
A->something
B->something

You can clearly see that palindromes cannot be expressed in regular grammar since it needs to be either right or left linear and as such cannot have a non-terminal on both side.

Since regular grammars are non-ambiguous, there is only one production rule for a given non-terminal, whereas there can be more than one in the case of a context-free grammar.

System.Net.WebException: The remote name could not be resolved:

I had a similar issue when trying to access a service (old ASMX service). The call would work when accessing via an IP however when calling with an alias I would get the remote name could not be resolved.

Added the following to the config and it resolved the issue:

<system.net>
    <defaultProxy enabled="true">
    </defaultProxy>
</system.net>

jQuery .search() to any string

search() is a String method.

You are executing the attr function on every <li> element. You need to invoke each and use the this reference within.

Example:

$('li').each(function() {
    var isFound = $(this).attr('title').search(/string/i);
    //do something based on isFound...
});

Combining border-top,border-right,border-left,border-bottom in CSS

No, you cannot set them all in a single statement.
At the general case, you need at least three properties:

border-color: red green white blue;
border-style: solid dashed dotted solid;
border-width: 1px 2px 3px 4px;

However, that would be quite messy. It would be more readable and maintainable with four:

border-top:    1px solid  #ff0;
border-right:  2px dashed #f0F;
border-bottom: 3px dotted #f00;
border-left:   5px solid  #09f;

Looping through JSON with node.js

If you want to avoid blocking, which is only necessary for very large loops, then wrap the contents of your loop in a function called like this: process.nextTick(function(){<contents of loop>}), which will defer execution until the next tick, giving an opportunity for pending calls from other asynchronous functions to be processed.

How to multiply duration by integer?

int32 and time.Duration are different types. You need to convert the int32 to a time.Duration, such as time.Sleep(time.Duration(rand.Int31n(1000)) * time.Millisecond).

git: fatal: Could not read from remote repository

I solved this issue by restarting the terminal (open a new window/tab).

So if you don't really want/need to understand the underlying problem, test method is worth a try before digging deeper :)

How to Implement Custom Table View Section Headers and Footers with Storyboard

In iOS 6.0 and above, things have changed with the new dequeueReusableHeaderFooterViewWithIdentifier API.

I have written a guide (tested on iOS 9), which can be summarised as such:

  1. Subclass UITableViewHeaderFooterView
  2. Create Nib with the subclass view, and add 1 container view which contains all other views in the header/footer
  3. Register the Nib in viewDidLoad
  4. Implement viewForHeaderInSection and use dequeueReusableHeaderFooterViewWithIdentifier to get back the header/footer

How can I add a PHP page to WordPress?

You can add any php file in under your active themes folder like (/wp-content/themes/your_active_theme/) and then you can go to add new page from wp-admin and select this page template from page template options.

<?php
/*
 Template Name: Your Template Name
 */
?>

And there is one other way like you can include your file in functions.php and create shortcode from that and then you can put that shortcode in your page like this.

// CODE in functions.php 

function abc(){
 include_once('your_file_name.php');
}
add_shortcode('abc' , 'abc');

And then you can use this shortcode in wp-admin side page like this [abc].

How to make bootstrap column height to 100% row height?

@Alan's answer will do what you're looking for, but this solution fails when you use the responsive capabilities of Bootstrap. In your case, you're using the xs sizes so you won't notice, but if you used anything else (e.g. col-sm, col-md, etc), you'd understand.

Another approach is to play with margins and padding. See the updated fiddle: http://jsfiddle.net/jz8j247x/1/

.left-side {
  background-color: blue;
  padding-bottom: 1000px;
  margin-bottom: -1000px;
  height: 100%;
}
.something {
  height: 100%;
  background-color: red;
  padding-bottom: 1000px;
  margin-bottom: -1000px;
  height: 100%;
}
.row {
  background-color: green;
  overflow: hidden;
}

Can't Autowire @Repository annotated interface in Spring Boot

I had a similar problem but with a different cause:

In my case the problem was that in the interface defining the repository

public interface ItemRepository extends Repository {..}

I was omitting the types of the template. Setting them right:

public interface ItemRepository extends Repository<Item,Long> {..}

did the trick.

How can I get the current directory name in Javascript?

An interesting approach to get the dirname of the current URL is to make use of your browser's built-in path resolution. You can do that by:

  1. Create a link to ., i.e. the current directory
  2. Use the HTMLAnchorElement interface of the link to get the resolved URL or path equivalent to ..

Here's one line of code that does just that:

Object.assign(document.createElement('a'), {href: '.'}).pathname

In contrast to some of the other solutions presented here, the result of this method will always have a trailing slash. E.g. running it on this page will yield /questions/3151436/, running it on https://stackoverflow.com/ will yield /.

It's also easy to get the full URL instead of the path. Just read the href property instead of pathname.

Finally, this approach should work in even the most ancient browsers if you don't use Object.assign:

function getCurrentDir () {
    var link = document.createElement('a');
    link.href = '.';
    return link.pathname;
}

What is the difference between function and procedure in PL/SQL?

In dead simple way it makes this meaning.

Functions :

These subprograms return a single value; mainly used to compute and return a value.

Procedure :

These subprograms do not return a value directly; mainly used to perform an action.

Example Program:

CREATE OR REPLACE PROCEDURE greetings

BEGIN 

dbms_output.put_line('Hello World!');

END ;
/

Executing a Standalone Procedure :

A standalone procedure can be called in two ways:

• Using the EXECUTE keyword • Calling the name of procedure from a PL/SQL block

The procedure can also be called from another PL/SQL block:

BEGIN 
greetings;
END;
/

Function:

CREATE OR REPLACE FUNCTION totalEmployees 
RETURN number IS
total number(3) := 0;
BEGIN 
SELECT count(*) into total 
FROM employees;
RETURN total; 
END;
/

Following program calls the function totalCustomers from an another block

DECLARE 
c number(3);
BEGIN 
c := totalEmployees();
dbms_output.put_line('Total no. of Employees: ' || c);
END;
/

Use FontAwesome or Glyphicons with css :before

In the case of your list items there is a little CSS you can use to achieve the desired effect.

ul.icons li {
  position: relative;
  padding-left: -20px; // for example
}
ul.icons li i {
  position: absolute;
  left: 0;
}

I have tested this in Safari on OS X.

Switch firefox to use a different DNS than what is in the windows.host file

I wonder if you could write a custom rule for Fiddler to do what you want? IE uses no proxy, Firefox points to Fiddler, Fiddler uses custom rule to direct requests to the dev server...

http://www.fiddlertool.com/fiddler/

Cannot open database "test" requested by the login. The login failed. Login failed for user 'xyz\ASPNET'

I have not seen this mentioned in the previous issues, so let me throw out another possibility. It could be that IFItest is not reachable or simply does not exist. For example, if one has a number of configurations, each with its own database, it could be that the database name was not changed to the correct one for the current configuration.

How to rotate portrait/landscape Android emulator?

Officially it's Ctrl+F11 & Ctrl+F12 or KEYPAD 7 & KEYPAD 9.

In practise it's a bit quirky.

  1. Specifically it's Left Ctrl+F11 and Left Ctrl+F12 to switch to previous orientation and next orientation respectively.

  2. You have to release Ctrl before you can rotate again.

  3. KEYPAD 7 and KEYPAD 9 only work with Num Lock OFF (so they're acting as Home & PageUp rather than 7 & 9).

  4. The only orientations are vertically upright and rotated one quarter-turn anti-clockwise.

Maybe a bit too much info for such a simple question, but it drove me half-mad finding this out.

Note: This was tested on Android SDK R16 and a very old keyboard, modern keyboards may behave differently.

Simple regular expression for a decimal with a precision of 2

Try this

 (\\+|-)?([0-9]+(\\.[0-9]+))

It will allow positive and negative signs also.

jQuery ui datepicker with Angularjs

I think you are missing the Angular ui bootstrap dependency in your module declaration, like this:

angular.module('elnApp', ['ui.bootstrap'])

See the doc for Angular-ui-bootstrap.

Viewing my IIS hosted site on other machines on my network

First of all, try to connect to the LAN IP of your server. If IIS is set up with only one web site, chances are that your site is going to pop up.

If you want to access it by name, you would have to add an entry in the HOSTS file of every client PC you want to view the site with (not to 127.0.0.1 obviously, but to the local IP address of your server).

Also, your Firewall needs to be configured to accept incoming calls on Port 80.

This is usually the point where it makes more sense to set up a DNS service that you can register names like "mysite.dev" with centrally, without having to dabble with hosts files. But that's a different story, and belongs to superuser.com or serverfault.com.

Android - styling seek bar

I would extract drawables and xml from Android source code and change its color to red. Here is example how I completed this for mdpi drawables:

Custom red_scrubber_control.xml (add to res/drawable):

<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:drawable="@drawable/red_scrubber_control_disabled_holo" android:state_enabled="false"/>
    <item android:drawable="@drawable/red_scrubber_control_pressed_holo" android:state_pressed="true"/>
    <item android:drawable="@drawable/red_scrubber_control_focused_holo" android:state_selected="true"/>
    <item android:drawable="@drawable/red_scrubber_control_normal_holo"/>
</selector>

Custom: red_scrubber_progress.xml

<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >

    <item
        android:id="@android:id/background"
        android:drawable="@drawable/red_scrubber_track_holo_light"/>
    <item android:id="@android:id/secondaryProgress">
        <scale
            android:drawable="@drawable/red_scrubber_secondary_holo"
            android:scaleWidth="100%" />
    </item>
    <item android:id="@android:id/progress">
        <scale
            android:drawable="@drawable/red_scrubber_primary_holo"
            android:scaleWidth="100%" />
    </item>

</layer-list>

Then copy required drawables from Android source code, I took from this link

It is good to copy these drawables for each hdpi, mdpi, xhdpi. For example I use only mdpi:

Then using Photoshop change color from blue to red:

red_scrubber_control_disabled_holo.png: red_scrubber_control_disabled_holo

red_scrubber_control_focused_holo.png: red_scrubber_control_focused_holo

red_scrubber_control_normal_holo.png: red_scrubber_control_normal_holo

red_scrubber_control_pressed_holo.png: red_scrubber_control_pressed_holo

red_scrubber_primary_holo.9.png: red_scrubber_primary_holo.9

red_scrubber_secondary_holo.9.png: red_scrubber_secondary_holo.9

red_scrubber_track_holo_light.9.png: red_scrubber_track_holo_light.9

Add SeekBar to layout:

<SeekBar
    android:id="@+id/seekBar1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:progressDrawable="@drawable/red_scrubber_progress"
    android:thumb="@drawable/red_scrubber_control" />

Result:

enter image description here

How do I declare an array variable in VBA?

As pointed out by others, your problem is that you have not declared an array

Below I've tried to recreate your program so that it works as you intended. I tried to leave as much as possible as it was (such as leaving your array as a variant)

Public Sub Testprog()
    '"test()" is an array, "test" is not
    Dim test() As Variant
    'I am assuming that iCounter is the array size
    Dim iCounter As Integer

    '"On Error Resume Next" just makes us skip over a section that throws the error
    On Error Resume Next

    'if test() has not been assigned a UBound or LBound yet, calling either will throw an error
    '   without an LBound and UBound an array won't hold anything (we will assign them later)

    'Array size can be determined by (UBound(test) - LBound(test)) + 1
    If (UBound(test) - LBound(test)) + 1 > 0 Then
        iCounter = (UBound(test) - LBound(test)) + 1

        'So that we don't run the code that deals with UBound(test) throwing an error
        Exit Sub
    End If

    'All the code below here will run if UBound(test)/LBound(test) threw an error
    iCounter = 0

    'This makes LBound(test) = 0
    '   and UBound(test) = iCounter where iCounter is 0
    '   Which gives us one element at test(0)
    ReDim Preserve test(0 To iCounter)

    test(iCounter) = "test"
End Sub

Git update submodules recursively

In recent Git (I'm using v2.15.1), the following will merge upstream submodule changes into the submodules recursively:

git submodule update --recursive --remote --merge

You may add --init to initialize any uninitialized submodules and use --rebase if you want to rebase instead of merge.

You need to commit the changes afterwards:

git add . && git commit -m 'Update submodules to latest revisions'

jQuery check if it is clicked or not

Using jQuery, I would suggest a shorter solution.

var elementClicked;
$("element").click(function(){
   elementClicked = true;
});
if( elementClicked != true ) {
    alert("element not clicked");
}else{
    alert("element clicked");
}

("element" here is to be replaced with the actual name tag)

Deleting multiple elements from a list

Importing it only for this reason might be overkill, but if you happen to be using pandas anyway, then the solution is simple and straightforward:

import pandas as pd
stuff = pd.Series(['a','b','a','c','a','d'])
less_stuff = stuff[stuff != 'a']  # define any condition here
# results ['b','c','d']

Python Request Post with param data

params is for GET-style URL parameters, data is for POST-style body information. It is perfectly legal to provide both types of information in a request, and your request does so too, but you encoded the URL parameters into the URL already.

Your raw post contains JSON data though. requests can handle JSON encoding for you, and it'll set the correct Content-Type header too; all you need to do is pass in the Python object to be encoded as JSON into the json keyword argument.

You could split out the URL parameters as well:

params = {'sessionKey': '9ebbd0b25760557393a43064a92bae539d962103', 'format': 'xml', 'platformId': 1}

then post your data with:

import requests

url = 'http://192.168.3.45:8080/api/v2/event/log'

data = {"eventType": "AAS_PORTAL_START", "data": {"uid": "hfe3hf45huf33545", "aid": "1", "vid": "1"}}
params = {'sessionKey': '9ebbd0b25760557393a43064a92bae539d962103', 'format': 'xml', 'platformId': 1}

requests.post(url, params=params, json=data)

The json keyword is new in requests version 2.4.2; if you still have to use an older version, encode the JSON manually using the json module and post the encoded result as the data key; you will have to explicitly set the Content-Type header in that case:

import requests
import json

headers = {'content-type': 'application/json'}
url = 'http://192.168.3.45:8080/api/v2/event/log'

data = {"eventType": "AAS_PORTAL_START", "data": {"uid": "hfe3hf45huf33545", "aid": "1", "vid": "1"}}
params = {'sessionKey': '9ebbd0b25760557393a43064a92bae539d962103', 'format': 'xml', 'platformId': 1}

requests.post(url, params=params, data=json.dumps(data), headers=headers)

TypeError: unsupported operand type(s) for -: 'list' and 'list'

The operations needed to be performed, require numpy arrays either created via

np.array()

or can be converted from list to an array via

np.stack()

As in the above mentioned case, 2 lists are inputted as operands it triggers the error.

How to delete/remove nodes on Firebase

To remove a record.

 var db = firebase.database();                   
 var ref = db.ref(); 
 var survey=db.ref(path+'/'+path);    //Eg path is company/employee                
 survey.child(key).remove();          //Eg key is employee id

Convert a 1D array to a 2D array in numpy

You want to reshape the array.

B = np.reshape(A, (-1, 2))

where -1 infers the size of the new dimension from the size of the input array.

How to append output to the end of a text file

Use the >> operator to append text to a file.

What are libtool's .la file for?

According to http://blog.flameeyes.eu/2008/04/14/what-about-those-la-files, they're needed to handle dependencies. But using pkg-config may be a better option:

In a perfect world, every static library needing dependencies would have its own .pc file for pkg-config, and every package trying to statically link to that library would be using pkg-config --static to get the libraries to link to.

ImageMagick security policy 'PDF' blocking conversion

Adding to Stefan Seidel's answer.

Well, at least in Ubuntu 20.04.2 LTS or maybe in other versions you can't really edit the policy.xml file directly in a GUI way. Here is a terminal way to edit it.

  1. Open the policy.xml file in terminal by entering this command -

    sudo nano /etc/ImageMagick-6/policy.xml

  2. Now, directly edit the file in terminal, find <policy domain="coder" rights="none" pattern="PDF" /> and replace none with read|write as shown in the picture. Then press Ctrl+X to exit.

Edit in terminal

Visual Studio Expand/Collapse keyboard shortcuts

Collapse to definitions

CTRL + M, O

Expand all outlining

CTRL + M, X

Expand or collapse everything

CTRL + M, L

This also works with other languages like TypeScript and JavaScript

Conda version pip install -r requirements.txt --target ./lib

You can always try this:

/home/user/anaconda3/bin/pip install -r requirements.txt

This simply uses the pip installed in the conda environment. If pip is not preinstalled in your environment you can always run the following command

conda install pip

php mysqli_connect: authentication method unknown to the client [caching_sha2_password]

As of PHP 7.4, this is no longer an issue. Support for caching_sha2 authentication method has been added to mysqlnd.


Currently, PHP mysqli extension do not support new caching_sha2 authentication feature. You have to wait until they release an update.

Check related post from MySQL developers: https://mysqlserverteam.com/upgrading-to-mysql-8-0-default-authentication-plugin-considerations/

They didn't mention PDO, maybe you should try to connect with PDO.

Use python requests to download CSV

The following approach worked well for me. I also did not need to use csv.reader() or csv.writer() functions, which I feel makes the code cleaner. The code is compatible with Python2 and Python 3.

from six.moves import urllib

DOWNLOAD_URL = "https://raw.githubusercontent.com/gjreda/gregreda.com/master/content/notebooks/data/city-of-chicago-salaries.csv"
DOWNLOAD_PATH ="datasets\city-of-chicago-salaries.csv" 
urllib.request.urlretrieve(URL,DOWNLOAD_PATH)

Note - six is a package that helps in writing code that is compatible with both Python 2 and Python 3. For additional details regarding six see - What does from six.moves import urllib do in Python?

How to force a SQL Server 2008 database to go Offline

Go offline

USE master
GO
ALTER DATABASE YourDatabaseName
SET OFFLINE WITH ROLLBACK IMMEDIATE
GO

Go online

USE master
GO
ALTER DATABASE YourDatabaseName
SET ONLINE
GO

bash string equality

There's no difference, == is a synonym for = (for the C/C++ people, I assume). See here, for example.

You could double-check just to be really sure or just for your interest by looking at the bash source code, should be somewhere in the parsing code there, but I couldn't find it straightaway.

How to set python variables to true or false?

you have to use capital True and False not true and false

Limiting Powershell Get-ChildItem by File Creation Date Range

Fixed it...

Get-ChildItem C:\Windows\ -recurse -include @("*.txt*","*.pdf") |
Where-Object {$_.CreationTime -gt "01/01/2013" -and $_.CreationTime -lt "12/02/2014"} | 
Select-Object FullName, CreationTime, @{Name="Mbytes";Expression={$_.Length/1Kb}}, @{Name="Age";Expression={(((Get-Date) - $_.CreationTime).Days)}} | 
Export-Csv C:\search_TXT-and-PDF_files_01012013-to-12022014_sort.txt

JS strings "+" vs concat method

You can try with this code (Same case)

chaine1 + chaine2; 

I suggest you also (I prefer this) the string.concat method

link with target="_blank" does not open in new tab in Chrome

Learn from another guy:

<a onclick="window.open(this.href,'_blank');return false;" href="http://www.foracure.org.au">Some Other Site</a>

It makes sense to me.

How to get last inserted row ID from WordPress database?

just like this :

global $wpdb;
$table_name='lorem_ipsum';
$results = $wpdb->get_results("SELECT * FROM $table_name ORDER BY ID DESC LIMIT 1");
print_r($results[0]->id);

simply your selecting all the rows then order them DESC by id , and displaying only the first

How do I see if Wi-Fi is connected on Android?

This is an easier solution. See Stack Overflow question Checking Wi-Fi enabled or not on Android.

P.S. Do not forget to add the code to the manifest.xml file to allow permission. As shown below.

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

Converting <br /> into a new line for use in a text area

Try this one

<?php
    $text = "Hello <br /> Hello again <br> Hello again again <br/> Goodbye <BR>";
    $breaks = array("<br />","<br>","<br/>");  
    $text = str_ireplace($breaks, "\r\n", $text);  
?>  
<textarea><?php echo $text; ?></textarea>

Python can't find module in the same folder

Change your import in test.py to:

from .hello import hello1

jQuery - select all text from a textarea

Better way, with solution to tab and chrome problem and new jquery way

$("#element").on("focus keyup", function(e){

        var keycode = e.keyCode ? e.keyCode : e.which ? e.which : e.charCode;
        if(keycode === 9 || !keycode){
            // Hacemos select
            var $this = $(this);
            $this.select();

            // Para Chrome's que da problema
            $this.on("mouseup", function() {
                // Unbindeamos el mouseup
                $this.off("mouseup");
                return false;
            });
        }
    });

Java Keytool error after importing certificate , "keytool error: java.io.FileNotFoundException & Access Denied"

I was having the same problem while importing the certificate in local keystore. Whenever i issue the keytool command i got the following error.

Certificate was added to keystore keytool error: java.io.FileNotFoundException: C:\Program Files\Java\jdk1.8.0_151\jre\lib\security (Access is denied)

Following solution work for me.

1) make sure you are running command prompt in Rus as Administrator mode

2) Change your current directory to %JAVA_HOME%\jre\lib\security

3) then Issue the below command

keytool -import -alias "mycertificatedemo" -file "C:\Users\name\Downloads\abc.crt" -keystore cacerts

3) give the password changeit

4) enter y

5) you will see the following message on successful "Certificate was added to keystore"

Make sure you are giving the "cacerts" only in -keystore param value , as i was giving the full path like "C**:\Program Files\Java\jdk1.8.0_151\jre\lib\security**".

Hope this will work

Generate Java class from JSON?

I created a github project Json2Java that does this. https://github.com/inder123/json2java

Json2Java provides customizations such as renaming fields, and creating inheritance hierarchies.

I have used the tool to create some relatively complex APIs:

Gracenote's TMS API: https://github.com/inder123/gracenote-java-api

Google Maps Geocoding API: https://github.com/inder123/geocoding

Inserting data into a MySQL table using VB.NET

your str_carSql should be exactly like this:

str_carSql = "insert into members_car (car_id, member_id, model, color, chassis_id, plate_number, code) values (@id,@m_id,@model,@color,@ch_id,@pt_num,@code)"

Good Luck

Python slice first and last element in list

Just thought I'd show how to do this with numpy's fancy indexing:

>>> import numpy
>>> some_list = ['1', 'B', '3', 'D', '5', 'F']
>>> numpy.array(some_list)[[0,-1]]
array(['1', 'F'], 
      dtype='|S1')

Note that it also supports arbitrary index locations, which the [::len(some_list)-1] method would not work for:

>>> numpy.array(some_list)[[0,2,-1]]
array(['1', '3', 'F'], 
      dtype='|S1')

As DSM points out, you can do something similar with itemgetter:

>>> import operator
>>> operator.itemgetter(0, 2, -1)(some_list)
('1', '3', 'F')

Zip folder in C#

From the DotNetZip help file, http://dotnetzip.codeplex.com/releases/

using (ZipFile zip = new ZipFile())
{
   zip.UseUnicodeAsNecessary= true;  // utf-8
   zip.AddDirectory(@"MyDocuments\ProjectX");
   zip.Comment = "This zip was created at " + System.DateTime.Now.ToString("G") ; 
   zip.Save(pathToSaveZipFile);
}

Apache shutdown unexpectedly

i think the error is here

[pid 5384:tid 240] AH01909: RSA certificate configured for www.example.com:443 does NOT include an ID which matches the server name

or there is another app are using the port 80 try restarting your computer and only opening apache and see what happens

or try on reinstalling apache or using Ampps

How to concatenate string variables in Bash

If you want to append something like an underscore, use escape (\)

FILEPATH=/opt/myfile

This does not work:

echo $FILEPATH_$DATEX

This works fine:

echo $FILEPATH\\_$DATEX

How do I "un-revert" a reverted Git commit?

Reverting the revert will do the trick

For example,

If abcdef is your commit and ghijkl is the commit you have when you reverted the commit abcdef, then run:

git revert ghijkl

This will revert the revert

jquery - check length of input field?

If you mean that you want to enable the submit after the user has typed at least one character, then you need to attach a key event that will check it for you.

Something like:

$("#fbss").keypress(function() {
    if($(this).val().length > 1) {
         // Enable submit button
    } else {
         // Disable submit button
    }
});

delete all from table

You can also use truncate.

truncate table table_name;

How to set Oracle's Java as the default Java in Ubuntu?

I put the line:

export JAVA_HOME=/usr/lib/jvm/java-7-oracle

in my ~/.bashrc file.

/usr/lib/jvm/java7-oracle should be a symbolic link pointing to /usr/lib/jvm/java-7-oracle-[version number here].

The reason it's a symbolic link is that in case there's a new version of the JVM, you don't need to update your .bashrc file, it should automatically point to the new version.

If you want to set JAVA_HOME environment variables globally and at system level means use should set in /etc/environment file.

git stash apply version

Since version 2.11, it's pretty easy, you can use the N stack number instead of saying "stash@{n}". So now instead of using:

git stash apply "stash@{n}"

You can type:

git stash apply n

For example, in your list:

stash@{0}: WIP on design: f2c0c72... Adjust Password Recover Email
stash@{1}: WIP on design: f2c0c72... Adjust Password Recover Email
stash@{2}: WIP on design: eb65635... Email Adjust
stash@{3}: WIP on design: eb65635... Email Adjust

If you want to apply stash@{1} you could type:

git stash apply 1

Otherwise, you can use it even if you have some changes in your directory since 1.7.5.1, but you must be sure the stash won't overwrite your working directory changes if it does you'll get an error:

error: Your local changes to the following files would be overwritten by merge:
        file
Please commit your changes or stash them before you merge.

In versions prior to 1.7.5.1, it refused to work if there was a change in the working directory.


Git release notes:

The user always has to say "stash@{$N}" when naming a single element in the default location of the stash, i.e. reflogs in refs/stash. The "git stash" command learned to accept "git stash apply 4" as a short-hand for "git stash apply stash@{4}"

git stash apply" used to refuse to work if there was any change in the working tree, even when the change did not overlap with the change the stash recorded

What do Push and Pop mean for Stacks?

  • push = add to the stack
  • pop = remove from the stack

List all tables in postgresql information_schema

\dt information_schema.

from within psql, should be fine.

How to resize a VirtualBox vmdk file

Here's a way to resize your VirtualBox disk, regardless of whether it is a fixed format or dynamic format disk. Specifically, it prevents the error you had when you disk is fixed-format.


?? Backup the virtual disk. You never know what might go wrong.

On your host:

  1. Open a terminal window.

    On Windows: Open the command prompt cmd.

  2. Go to the directory with the virtual disk you want to resize. For example:

    cd "My VMs"
    
  3. Create a new VirtualBox disk with your desired filename, size (in megabytes) and format (either Standard (dynamic) or Fixed). For example, to create a 50 GB fixed-format disk called MyNewDisk.vdi:

    VBoxManage createmedium --filename "MyNewDisk.vdi" --size 50000 --variant Fixed
    

    If VBoxManage is not recognized as a command, specify the full path to it. It can be found in the VirtualBox installation directory. On Windows the above command would become:

    "C:\Program Files\Oracle\VirtualBox\VBoxManage.exe" createmedium
        --filename "MyNewDisk.vdi" --size 50000 --variant Fixed
    
  4. Copy the original disk to the new disk.

    VBoxManage clonemedium "MyOriginalDisk.vdi" "MyNewDisk.vdi" --existing
    
  5. The resize is done! You can check the properties of the new disk if you want:

    VBoxManage showmediuminfo "MyNewDisk.vdi"
    
  6. Change the virtual machine to use the new disk instead.

Next, on your guest OS you need to resize the partitions to use the newly available space.

Python 2.7: %d, %s, and float()

See String Formatting Operations:

%d is the format code for an integer. %f is the format code for a float.

%s prints the str() of an object (What you see when you print(object)).

%r prints the repr() of an object (What you see when you print(repr(object)).

For a float %s, %r and %f all display the same value, but that isn't the case for all objects. The other fields of a format specifier work differently as well:

>>> print('%10.2s' % 1.123) # print as string, truncate to 2 characters in a 10-place field.
        1.
>>> print('%10.2f' % 1.123) # print as float, round to 2 decimal places in a 10-place field.
      1.12

Joining 2 SQL SELECT result sets into one

SELECT table1.col_a, table1.col_b, table2.col_c 
  FROM table1 
  INNER JOIN table2 ON table1.col_a = table2.col_a

Changing case in Vim

See the following methods:

 ~    : Changes the case of current character

 guu  : Change current line from upper to lower.

 gUU  : Change current LINE from lower to upper.

 guw  : Change to end of current WORD from upper to lower.

 guaw : Change all of current WORD to lower.

 gUw  : Change to end of current WORD from lower to upper.

 gUaw : Change all of current WORD to upper.

 g~~  : Invert case to entire line

 g~w  : Invert case to current WORD

 guG : Change to lowercase until the end of document.

PHP MySQL Google Chart JSON - Complete Example

Some might encounter this error (I got it while implementing PHP-MySQLi-JSON-Google Chart Example):

You called the draw() method with the wrong type of data rather than a DataTable or DataView.

The solution would be: replace jsapi and just use loader.js with:

google.charts.load('current', {packages: ['corechart']}) and 
google.charts.setOnLoadCallback 

-- according to the release notes --> The version of Google Charts that remains available via the jsapi loader is no longer being updated consistently. Please use the new gstatic loader from now on.

HTML not loading CSS file

This may be a 'special' case but was fiddling with this piece of code:

ForceType application/x-httpd-php SetHandler application/x-httpd-php

As a quick test for extentionless file handling, when a similar problem occurred.

Some but not all php files thereafter treated the css files as php and thus succesfully loaded the css but not handled it as css, thus zero rules were executed when checking f12 style editor.

Perhaps something similar might occur to any-one else here and this tidbit might help.

Operation must use an updatable query. (Error 3073) Microsoft Access

(A little late to the party...)

The three ways I've gotten around this problem in the past are:

  1. Reference a text box on an open form
  2. DSum
  3. DLookup

How to stretch the background image to fill a div

You can use:

background-size: cover;

Or just use a big background image with:

background: url('../images/teaser.jpg') no-repeat center #eee;

When do you use POST and when do you use GET?

Use POST for destructive actions such as creation (I'm aware of the irony), editing, and deletion, because you can't hit a POST action in the address bar of your browser. Use GET when it's safe to allow a person to call an action. So a URL like:

http://myblog.org/admin/posts/delete/357

Should bring you to a confirmation page, rather than simply deleting the item. It's far easier to avoid accidents this way.

POST is also more secure than GET, because you aren't sticking information into a URL. And so using GET as the method for an HTML form that collects a password or other sensitive information is not the best idea.

One final note: POST can transmit a larger amount of information than GET. 'POST' has no size restrictions for transmitted data, whilst 'GET' is limited to 2048 characters.

std::string to float or double

My Problem:

  1. Locale independent string to double (decimal separator always '.')
  2. Error detection if string conversion fails

My solution (uses the Windows function _wcstod_l):

// string to convert. Note: decimal seperator is ',' here
std::wstring str = L"1,101";

// Use this for error detection
wchar_t* stopString;

// Create a locale for "C". Thus a '.' is expected as decimal separator
double dbl = _wcstod_l(str.c_str(), &stopString, _create_locale(LC_ALL, "C")); 

if (wcslen(stopString) != 0)
{
    // ... error handling ... we'll run into this because of the separator
}

HTH ... took me pretty long to get to this solution. And I still have the feeling that I don't know enough about string localization and stuff...

Project Links do not work on Wamp Server

You can follow all steps by @RiggsFolly thats is really good answer, If you do not want to create virtual host and want to use like previous localhost/example/ or something like that you can use answer by @Arunu

But if you still face problem please use this method,

  1. Locate your wamp folder (Eg. c:/Wamp/) where you have installed
  2. Goto Wamp/www/
  3. Open index.php file
  4. find this code $projectContents .= '<li><a href="'.($suppress_localhost ? 'http://' : '').$file.'">'.$file.'</a></li>';
  5. modify it add localhost after http:// $projectContents .= '<li><a href="'.($suppress_localhost ? 'http://localhost' : '').$file.'">'.$file.'</a></li>';
  6. Restart wamp server
  7. open localhost see the updated links

Hope you got your url like previous version of wamp server.

Matching special characters and letters in regex

let pattern = /^(?=.*[0-9])(?=.*[!@#$%^&*])(?=.*[a-z])(?=.*[A-Z])[a-zA-Z0-9!@#$%^&*]{6,16}$/;

//following will give you the result as true(if the password contains Capital, small letter, number and special character) or false based on the string format

let reee =pattern .test("helLo123@");   //true as it contains all the above

How to specify names of columns for x and y when joining in dplyr?

This is more a workaround than a real solution. You can create a new object test_data with another column name:

left_join("names<-"(test_data, "name"), kantrowitz, by = "name")

     name gender
1    john      M
2    bill either
3 madison      M
4    abby either
5     zzz   <NA>

Python - Count elements in list

just do len(MyList)

This also works for strings, tuples, dict objects.

What is the purpose of meshgrid in Python / NumPy?

meshgrid helps in creating a rectangular grid from two 1-D arrays of all pairs of points from the two arrays.

x = np.array([0, 1, 2, 3, 4])
y = np.array([0, 1, 2, 3, 4])

Now, if you have defined a function f(x,y) and you wanna apply this function to all the possible combination of points from the arrays 'x' and 'y', then you can do this:

f(*np.meshgrid(x, y))

Say, if your function just produces the product of two elements, then this is how a cartesian product can be achieved, efficiently for large arrays.

Referred from here

Make sure that the controller has a parameterless public constructor error

I had the same problem. I googled it for two days. At last I accidentally noticed that the problem was access modifier of the constructor of the Controller. I didn’t put the public key word behind the Controller’s constructor.

public class MyController : ApiController
    {
        private readonly IMyClass _myClass;

        public MyController(IMyClass myClass)
        {
            _myClass = myClass;
        }
    }

I add this experience as another answer maybe someone else made a similar mistake.

Android emulator doesn't take keyboard input - SDK tools rev 20

Here is some workaround that actually worked for me, it is the same solution as in the most popular answer - just add hw.keyboard=yes to config.ini but since this didn't work for me I additionally

  1. renamed config.ini (any name will do) to something like consssssfig.ini
  2. restarted emulator (obviously it didn't start)
  3. renamed config.ini back again
  4. (I am not sure if relevant) I added this new parameter (hw.keyboard=yes) at the beggining of config.ini file

IIS7 Settings File Locations

Also check this answer from here: Cannot manually edit applicationhost.config

The answer is simple, if not that obvious: win2008 is 64bit, notepad++ is 32bit. When you navigate to Windows\System32\inetsrv\config using explorer you are using a 64bit program to find the file. When you open the file using using notepad++ you are trying to open it using a 32bit program. The confusion occurs because, rather than telling you that this is what you are doing, windows allows you to open the file but when you save it the file's path is transparently mapped to Windows\SysWOW64\inetsrv\Config.

So in practice what happens is you open applicationhost.config using notepad++, make a change, save the file; but rather than overwriting the original you are saving a 32bit copy of it in Windows\SysWOW64\inetsrv\Config, therefore you are not making changes to the version that is actually used by IIS. If you navigate to the Windows\SysWOW64\inetsrv\Config you will find the file you just saved.

How to get around this? Simple - use a 64bit text editor, such as the normal notepad that ships with windows.

WCF error - There was no endpoint listening at

Different case but may help someone,

In my case Window firewall was enabled on Server,

Two thinks can be done,

1) Disable windows firewall (your on risk but it will get thing work)

2) Add port in inbound rule.

Thanks .

How to read data From *.CSV file using javascript?

$(function() {

      $("#upload").bind("click", function() {
            var regex = /^([a-zA-Z0-9\s_\\.\-:])+(.csv|.xlsx)$/;
            if (regex.test($("#fileUpload").val().toLowerCase())) {
              if (typeof(FileReader) != "undefined") {
                var reader = new FileReader();
                reader.onload = function(e) {
                    var customers = new Array();
                    var rows = e.target.result.split("\r\n");
                    for (var i = 0; i < rows.length - 1; i++) {
                      var cells = rows[i].split(",");
                      if (cells[0] == "" || cells[0] == undefined) {
                        var s = customers[customers.length - 1];
                        s.Ord.push(cells[2]);
                      } else {
                        var dt = customers.find(x => x.Number === cells[0]);
                        if (dt == undefined) {
                          if (cells.length > 1) {
                            var customer = {};
                            customer.Number = cells[0];
                            customer.Name = cells[1];
                            customer.Ord = new Array();

                            customer.Ord.push(cells[2]);
                            customer.Point_ID = cells[3];
                            customer.Point_Name = cells[4];
                            customer.Point_Type = cells[5];
                            customer.Set_ORD = cells[6];
                            customers.push(customer);
                          }
                        } else {
                          var dtt = dt;
                          dtt.Ord.push(cells[2]);

                        }
                      }
                    }

How to print something when running Puppet client?

You can run the client like this ...

puppet agent --test --debug --noop

with that command you get all the output you can get.

excerpt puppet agent help
* --test:
  Enable the most common options used for testing. These are 'onetime',
  'verbose', 'ignorecache', 'no-daemonize', 'no-usecacheonfailure',
  'detailed-exitcodes', 'no-splay', and 'show_diff'.

NOTE: No need to include --verbose when you use the --test|-t switch, it implies the --verbose as well.

MaxLength Attribute not generating client-side validation attributes

Try using the [StringLength] attribute:

[Required(ErrorMessage = "Name is required.")]
[StringLength(40, ErrorMessage = "Name cannot be longer than 40 characters.")]
public string Name { get; set; }

That's for validation purposes. If you want to set for example the maxlength attribute on the input you could write a custom data annotations metadata provider as shown in this post and customize the default templates.

Quickest way to convert a base 10 number to any base in .NET?

If anyone is seeking a VB option, this was based on Pavel's answer:

Public Shared Function ToBase(base10 As Long, Optional baseChars As String = "0123456789ABCDEFGHIJKLMNOPQRTSUVWXYZ") As String

    If baseChars.Length < 2 Then Throw New ArgumentException("baseChars must be at least 2 chars long")

    If base10 = 0 Then Return baseChars(0)

    Dim isNegative = base10 < 0
    Dim radix = baseChars.Length
    Dim index As Integer = 64 'because it's how long a string will be if the basechars are 2 long (binary)
    Dim chars(index) As Char '65 chars, 64 from above plus one for sign if it's negative

    base10 = Math.Abs(base10)


    While base10 > 0
        chars(index) = baseChars(base10 Mod radix)
        base10 \= radix

        index -= 1
    End While

    If isNegative Then
        chars(index) = "-"c
        index -= 1
    End If

    Return New String(chars, index + 1, UBound(chars) - index)

End Function

getting integer values from textfield

As You're getting values from textfield as jTextField3.getText();.

As it is a textField it will return you string format as its format says:

String getText()

      Returns the text contained in this TextComponent.

So, convert your String to Integer as:

int jml = Integer.parseInt(jTextField3.getText());

instead of directly setting

   int jml = jTextField3.getText();

How to know which is running in Jupyter notebook?

import sys
print(sys.executable)
print(sys.version)
print(sys.version_info)

Seen below :- output when i run JupyterNotebook outside a CONDA venv

/home/dhankar/anaconda2/bin/python
2.7.12 |Anaconda 4.2.0 (64-bit)| (default, Jul  2 2016, 17:42:40) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)]
sys.version_info(major=2, minor=7, micro=12, releaselevel='final', serial=0)
 

Seen below when i run same JupyterNoteBook within a CONDA Venv created with command --

conda create -n py35 python=3.5 ## Here - py35 , is name of my VENV

in my Jupyter Notebook it prints :-

/home/dhankar/anaconda2/envs/py35/bin/python
3.5.2 |Continuum Analytics, Inc.| (default, Jul  2 2016, 17:53:06) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)]
sys.version_info(major=3, minor=5, micro=2, releaselevel='final', serial=0)

also if you already have various VENV's created with different versions of Python you switch to the desired Kernel by choosing KERNEL >> CHANGE KERNEL from within the JupyterNotebook menu... JupyterNotebookScreencapture

Also to install ipykernel within an existing CONDA Virtual Environment -

http://ipython.readthedocs.io/en/stable/install/kernel_install.html#kernels-for-different-environments

Source --- https://github.com/jupyter/notebook/issues/1524

 $ /path/to/python -m  ipykernel install --help
 usage: ipython-kernel-install [-h] [--user] [--name NAME]
                          [--display-name DISPLAY_NAME]
                          [--profile PROFILE] [--prefix PREFIX]
                          [--sys-prefix]

Install the IPython kernel spec.

optional arguments: -h, --help show this help message and exit --user Install for the current user instead of system-wide --name NAME Specify a name for the kernelspec. This is needed to have multiple IPython kernels at the same time. --display-name DISPLAY_NAME Specify the display name for the kernelspec. This is helpful when you have multiple IPython kernels. --profile PROFILE Specify an IPython profile to load. This can be used to create custom versions of the kernel. --prefix PREFIX Specify an install prefix for the kernelspec. This is needed to install into a non-default location, such as a conda/virtual-env. --sys-prefix Install to Python's sys.prefix. Shorthand for --prefix='/Users/bussonniermatthias/anaconda'. For use in conda/virtual-envs.

How do I temporarily disable triggers in PostgreSQL?

PostgreSQL knows the ALTER TABLE tblname DISABLE TRIGGER USER command, which seems to do what I need. See ALTER TABLE.

Automatically enter SSH password with script

If you are doing this on a Windows system, you can use Plink (part of PuTTY).

plink your_username@yourhost -pw your_password

Convert numpy array to tuple

I was not satisfied, so I finally used this:

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

>>> tuple(a.reshape(1, -1)[0])
(1, 2, 3, 4, 5, 6)

I don't know if it's quicker, but it looks more effective ;)

Execute Insert command and return inserted Id in Sql

The following solution will work with sql server 2005 and above. You can use output to get the required field. inplace of id you can write your key that you want to return. do it like this

FOR SQL SERVER 2005 and above

    using(SqlCommand cmd=new SqlCommand("INSERT INTO Mem_Basic(Mem_Na,Mem_Occ) output INSERTED.ID VALUES(@na,@occ)",con))
    {
        cmd.Parameters.AddWithValue("@na", Mem_NA);
        cmd.Parameters.AddWithValue("@occ", Mem_Occ);
        con.Open();

        int modified =(int)cmd.ExecuteScalar();

        if (con.State == System.Data.ConnectionState.Open) 
            con.Close();

        return modified;
    }
}

FOR previous versions

    using(SqlCommand cmd=new SqlCommand("INSERT INTO Mem_Basic(Mem_Na,Mem_Occ)  VALUES(@na,@occ);SELECT SCOPE_IDENTITY();",con))
    {
        cmd.Parameters.AddWithValue("@na", Mem_NA);
        cmd.Parameters.AddWithValue("@occ", Mem_Occ);
        con.Open();

        int modified = Convert.ToInt32(cmd.ExecuteScalar());

        if (con.State == System.Data.ConnectionState.Open) con.Close();
            return modified;
    }
}

How can I create a dynamic button click event on a dynamic button?

You can create button in a simple way, such as:

Button button = new Button();
button.Click += new EventHandler(button_Click);

protected void button_Click (object sender, EventArgs e)
{
    Button button = sender as Button;
    // identify which button was clicked and perform necessary actions
}

But event probably will not fire, because the element/elements must be recreated at every postback or you will lose the event handler.

I tried this solution that verify that ViewState is already Generated and recreate elements at every postback,

for example, imagine you create your button on an event click:

    protected void Button_Click(object sender, EventArgs e)
    {
       if (Convert.ToString(ViewState["Generated"]) != "true")
        {
            CreateDynamicElements();
        }
    
    }

on postback, for example on page load, you should do this:

    protected void Page_Load(object sender, EventArgs e)
    {
        if (Convert.ToString(ViewState["Generated"]) == "true") {
            CreateDynamicElements();
        }
    }

In CreateDynamicElements() you can put all the elements you need, such as your button.

This worked very well for me.

public void CreateDynamicElements(){

    Button button = new Button();
    button.Click += new EventHandler(button_Click);

}

How to auto resize and adjust Form controls with change in resolution

..and to detect a change in resolution to handle it (once you're using Docking and Anchoring like SwDevMan81 suggested) use the SystemEvents.DisplaySettingsChanged event in Microsoft.Win32.

How to get file URL using Storage facade in laravel 5?

Take a look at this: How to use storage_path() to view an image in laravel 4 . The same applies to Laravel 5:

Storage is for the file system, and the most part of it is not accessible to the web server. The recommended solution is to store the images somewhere in the public folder (which is the document root), in the public/screenshots/ for example. Then when you want to display them, use asset('screenshots/1.jpg').

In Javascript/jQuery what does (e) mean?

Today I just wrote a post about "Why do we use the letters like “e” in e.preventDefault()?" and I think my answer will make some sense...

At first,let us see the syntax of addEventListener

Normally it will be: target.addEventListener(type, listener[, useCapture]);

And the definition of the parameters of addEventlistener are:

type :A string representing the event type to listen out for.

listener :The object which receives a notification (an object that implements the Event interface) when an event of the specified type occurs. This must be an object implementing the EventListener interface, or a JavaScript function.

(From MDN)

But I think there is one thing should be remarked: When you use Javascript function as the listener, the object that implements the Event interface(object event) will be automatically assigned to the "first parameter" of the function.So,if you use function(e) ,the object will be assigned to "e" because "e" is the only parameter of the function(definitly the first one !),then you can use e.preventDefault to prevent something....

let us try the example as below:

<p>Please click on the checkbox control.</p>
<form>
    <label for="id-checkbox">Checkbox</label>
    <input type="checkbox" id="id-checkbox"/>

    </div>
</form>
<script>
    document.querySelector("#id-checkbox").addEventListener("click", function(e,v){
         //var e=3;
         var v=5;
         var t=e+v;
         console.log(t);
        e.preventDefault();

    }, false);
</script>

the result will be : [object MouseEvent]5 and you will prevent the click event.

but if you remove the comment sign like :

<script>
       document.querySelector("#id-checkbox").addEventListener("click", function(e,v){
            var e=3;
            var v=5;
            var t=e+v;
            console.log(t);
            e.preventDefault();

       }, false);
   </script>

you will get : 8 and an error:"Uncaught TypeError: e.preventDefault is not a function at HTMLInputElement. (VM409:69)".

Certainly,the click event will not be prevented this time.Because the "e" was defined again in the function.

However,if you change the code to:

<script>
       document.querySelector("#id-checkbox").addEventListener("click", function(e,v){
            var e=3;
            var v=5;
            var t=e+v;
            console.log(t);
            event.preventDefault();

       }, false);
   </script>

every thing will work propertly again...you will get 8 and the click event be prevented...

Therefore, "e" is just a parameter of your function and you need an "e" in you function() to receive the "event object" then perform e.preventDefault(). This is also the reason why you can change the "e" to any words that is not reserved by js.

MySQL, Check if a column exists in a table with SQL

DO NOT put ALTER TABLE/MODIFY COLS or any other such table mod operations inside a TRANSACTION. Transactions are for being able to roll back a QUERY failure not for ALTERations...it will error out every time in a transaction.

Just run a SELECT * query on the table and check if the column is there...

Git cli: get user info from username

There are no "usernames" in Git.

When creating a commit with Git it uses the configuration values of user.name (the real name) and user.email (email address). Those config values can be overridden on the console by setting and exporting the environment variables GIT_{COMMITTER,AUTHOR}_{NAME,EMAIL}.

Git doesn't know anything about github's users, because github is not part of Git. So you're only left with an API call to github (I guess you could do that from the command line with a little scripting.)

Iteration ng-repeat only X times in AngularJs

All answers here seem to assume that items is an array. However, in AngularJS, it might as well be an object. In that case, neither filtering with limitTo nor array.slice will work. As one possible solution, you can convert your object to an array, if you don't mind losing the object keys. Here is an example of a filter to do just that:

myFilter.filter('obj2arr', function() {
    return function(obj) {
        if (typeof obj === 'object') {
            var arr = [], i = 0, key;
            for( key in obj ) {
                arr[i] = obj[key];
                i++;
            }
            return arr;
        }
        else {
            return obj;
        }

    };
});

Once it is an array, use slice or limitTo, as stated in other answers.

Difference between a theta join, equijoin and natural join

While the answers explaining the exact differences are fine, I want to show how the relational algebra is transformed to SQL and what the actual value of the 3 concepts is.

The key concept in your question is the idea of a join. To understand a join you need to understand a Cartesian Product (the example is based on SQL where the equivalent is called a cross join as onedaywhen points out);

This isn't very useful in practice. Consider this example.

Product(PName, Price)
====================
Laptop,   1500
Car,      20000
Airplane, 3000000


Component(PName, CName, Cost)
=============================
Laptop, CPU,    500
Laptop, hdd,    300
Laptop, case,   700
Car,    wheels, 1000

The Cartesian product Product x Component will be - bellow or sql fiddle. You can see there are 12 rows = 3 x 4. Obviously, rows like "Laptop" with "wheels" have no meaning, this is why in practice the Cartesian product is rarely used.

|    PNAME |   PRICE |  CNAME | COST |
--------------------------------------
|   Laptop |    1500 |    CPU |  500 |
|   Laptop |    1500 |    hdd |  300 |
|   Laptop |    1500 |   case |  700 |
|   Laptop |    1500 | wheels | 1000 |
|      Car |   20000 |    CPU |  500 |
|      Car |   20000 |    hdd |  300 |
|      Car |   20000 |   case |  700 |
|      Car |   20000 | wheels | 1000 |
| Airplane | 3000000 |    CPU |  500 |
| Airplane | 3000000 |    hdd |  300 |
| Airplane | 3000000 |   case |  700 |
| Airplane | 3000000 | wheels | 1000 |

JOINs are here to add more value to these products. What we really want is to "join" the product with its associated components, because each component belongs to a product. The way to do this is with a join:

Product JOIN Component ON Pname

The associated SQL query would be like this (you can play with all the examples here)

SELECT *
FROM Product
JOIN Component
  ON Product.Pname = Component.Pname

and the result:

|  PNAME | PRICE |  CNAME | COST |
----------------------------------
| Laptop |  1500 |    CPU |  500 |
| Laptop |  1500 |    hdd |  300 |
| Laptop |  1500 |   case |  700 |
|    Car | 20000 | wheels | 1000 |

Notice that the result has only 4 rows, because the Laptop has 3 components, the Car has 1 and the Airplane none. This is much more useful.

Getting back to your questions, all the joins you ask about are variations of the JOIN I just showed:

Natural Join = the join (the ON clause) is made on all columns with the same name; it removes duplicate columns from the result, as opposed to all other joins; most DBMS (database systems created by various vendors such as Microsoft's SQL Server, Oracle's MySQL etc. ) don't even bother supporting this, it is just bad practice (or purposely chose not to implement it). Imagine that a developer comes and changes the name of the second column in Product from Price to Cost. Then all the natural joins would be done on PName AND on Cost, resulting in 0 rows since no numbers match.

Theta Join = this is the general join everybody uses because it allows you to specify the condition (the ON clause in SQL). You can join on pretty much any condition you like, for example on Products that have the first 2 letters similar, or that have a different price. In practice, this is rarely the case - in 95% of the cases you will join on an equality condition, which leads us to:

Equi Join = the most common one used in practice. The example above is an equi join. Databases are optimized for this type of joins! The oposite of an equi join is a non-equi join, i.e. when you join on a condition other than "=". Databases are not optimized for this! Both of them are subsets of the general theta join. The natural join is also a theta join but the condition (the theta) is implicit.

Source of information: university + certified SQL Server developer + recently completed the MOO "Introduction to databases" from Stanford so I dare say I have relational algebra fresh in mind.

How can I change the font-size of a select option?

select[value="value"]{
   background-color: red;
   padding: 3px;
   font-weight:bold;
}

Detect if checkbox is checked or unchecked in Angular.js ng-change event

The state of the checkbox will be reflected on whatever model you have it bound to, in this case, $scope.answers[item.questID]

How can I make a JUnit test wait?

There is a general problem: it's hard to mock time. Also, it's really bad practice to place long running/waiting code in a unit test.

So, for making a scheduling API testable, I used an interface with a real and a mock implementation like this:

public interface Clock {
    
    public long getCurrentMillis();
    
    public void sleep(long millis) throws InterruptedException;
    
}

public static class SystemClock implements Clock {

    @Override
    public long getCurrentMillis() {
        return System.currentTimeMillis();
    }

    @Override
    public void sleep(long millis) throws InterruptedException {
        Thread.sleep(millis);
    }
    
}

public static class MockClock implements Clock {

    private final AtomicLong currentTime = new AtomicLong(0);
    

    public MockClock() {
        this(System.currentTimeMillis());
    }
    
    public MockClock(long currentTime) {
        this.currentTime.set(currentTime);
    }
    

    @Override
    public long getCurrentMillis() {
        return currentTime.addAndGet(5);
    }

    @Override
    public void sleep(long millis) {
        currentTime.addAndGet(millis);
    }
    
}

With this, you could imitate time in your test:

@Test
public void testExpiration() {
    MockClock clock = new MockClock();
    SomeCacheObject sco = new SomeCacheObject();
    sco.putWithExpiration("foo", 1000);
    clock.sleep(2000) // wait for 2 seconds
    assertNull(sco.getIfNotExpired("foo"));
}

An advanced multi-threading mock for Clock is much more complex, of course, but you can make it with ThreadLocal references and a good time synchronization strategy, for example.

How can I display a list view in an Android Alert Dialog?

Use the "import android.app.AlertDialog;" import and then you write

    String[] items = {"...","...."};             
    AlertDialog.Builder build = new AlertDialog.Builder(context);
    build.setItems(items, new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            //do stuff....
        }
    }).create().show();

What JSON library to use in Scala?

I use uPickle which has the big advantage that it will handle nested case classes automatically:

object SerializingApp extends App {

  case class Person(name: String, address: Address)

  case class Address(street: String, town: String, zipCode: String)

  import upickle.default._

  val john = Person("John Doe", Address("Elm Street 1", "Springfield", "ABC123"))

  val johnAsJson = write(john)
  // Prints {"name":"John Doe","address":{"street":"Elm Street 1","town":"Springfield","zipCode":"ABC123"}}
  Console.println(johnAsJson)

  // Parse the JSON back into a Scala object
  Console.println(read[Person](johnAsJson))  
}

Add this to your build.sbt to use uPickle:

libraryDependencies += "com.lihaoyi" %% "upickle" % "0.4.3"

Python "SyntaxError: Non-ASCII character '\xe2' in file"

Change the file character encoding,

put below line to top of your code always

# -*- coding: utf-8 -*-

In Perl, what is the difference between a .pm (Perl module) and .pl (Perl script) file?

At the very core, the file extension you use makes no difference as to how perl interprets those files.

However, putting modules in .pm files following a certain directory structure that follows the package name provides a convenience. So, if you have a module Example::Plot::FourD and you put it in a directory Example/Plot/FourD.pm in a path in your @INC, then use and require will do the right thing when given the package name as in use Example::Plot::FourD.

The file must return true as the last statement to indicate successful execution of any initialization code, so it's customary to end such a file with 1; unless you're sure it'll return true otherwise. But it's better just to put the 1;, in case you add more statements.

If EXPR is a bareword, the require assumes a ".pm" extension and replaces "::" with "/" in the filename for you, to make it easy to load standard modules. This form of loading of modules does not risk altering your namespace.

All use does is to figure out the filename from the package name provided, require it in a BEGIN block and invoke import on the package. There is nothing preventing you from not using use but taking those steps manually.

For example, below I put the Example::Plot::FourD package in a file called t.pl, loaded it in a script in file s.pl.

C:\Temp> cat t.pl
package Example::Plot::FourD;

use strict; use warnings;

sub new { bless {} => shift }

sub something { print "something\n" }

"Example::Plot::FourD"

C:\Temp> cat s.pl
#!/usr/bin/perl
use strict; use warnings;

BEGIN {
    require 't.pl';
}

my $p = Example::Plot::FourD->new;
$p->something;


C:\Temp> s
something

This example shows that module files do not have to end in 1, any true value will do.

Resetting a form in Angular 2 after submit

Now NgForm supports two methods: .reset() vs .resetForm() the latter also changes the submit state of the form to false reverting form and its controls to initial states.

How to get process ID of background process?

  • $$ is the current script's pid
  • $! is the pid of the last background process

Here's a sample transcript from a bash session (%1 refers to the ordinal number of background process as seen from jobs):

$ echo $$
3748

$ sleep 100 &
[1] 192

$ echo $!
192

$ kill %1

[1]+  Terminated              sleep 100

how to insert date and time in oracle?

Just use TO_DATE() function to convert string to DATE.

For Example:

create table Customer(
       CustId int primary key,
       CustName varchar(20),
       DOB date);

insert into Customer values(1,'Vishnu', TO_DATE('1994/12/16 12:00:00', 'yyyy/mm/dd hh:mi:ss'));

How to put attributes via XElement

Add XAttribute in the constructor of the XElement, like

new XElement("Conn", new XAttribute("Server", comboBox1.Text));

You can also add multiple attributes or elements via the constructor

new XElement("Conn", new XAttribute("Server", comboBox1.Text), new XAttribute("Database", combobox2.Text));

or you can use the Add-Method of the XElement to add attributes

XElement element = new XElement("Conn");
XAttribute attribute = new XAttribute("Server", comboBox1.Text);
element.Add(attribute);

How do I perform query filtering in django templates

The other option is that if you have a filter that you always want applied, to add a custom manager on the model in question which always applies the filter to the results returned.

A good example of this is a Event model, where for 90% of the queries you do on the model you are going to want something like Event.objects.filter(date__gte=now), i.e. you're normally interested in Events that are upcoming. This would look like:

class EventManager(models.Manager):
    def get_query_set(self):
        now = datetime.now()
        return super(EventManager,self).get_query_set().filter(date__gte=now)

And in the model:

class Event(models.Model):
    ...
    objects = EventManager()

But again, this applies the same filter against all default queries done on the Event model and so isn't as flexible some of the techniques described above.

List of IP Space used by Facebook

# Bloqueio facebook
for ip in `whois -h whois.radb.net '!gAS32934' | grep /`
do
  iptables -A FORWARD -p all -d $ip -j REJECT
done

javascript regex for special characters

How about this:-

var regularExpression = /^(?=.*[0-9])(?=.*[!@#$%^&*])[a-zA-Z0-9!@#$%^&*]{6,}$/;

It will allow a minimum of 6 characters including numbers, alphabets, and special characters

Create a List of primitive int?

Java Collection should be collections of Object only.

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

Integer is wrapper class of primitive data type int.

more from JAVA wrapper classes here!

U can directly save and get int to/from integerList as, integerList.add(intValue); int intValue = integerList.get(i)

Local file access with JavaScript

if you are using angularjs & aspnet/mvc, to retrieve json files, you have to allow mime type at web config

<staticContent>
    <remove fileExtension=".json" />
    <mimeMap fileExtension=".json" mimeType="application/json" />
  </staticContent>

What's the reason I can't create generic array types in Java?

The reason this is impossible is that Java implements its Generics purely on the compiler level, and there is only one class file generated for each class. This is called Type Erasure.

At runtime, the compiled class needs to handle all of its uses with the same bytecode. So, new T[capacity] would have absolutely no idea what type needs to be instantiated.

What is the difference between a 'closure' and a 'lambda'?

There is a lot of confusion around lambdas and closures, even in the answers to this StackOverflow question here. Instead of asking random programmers who learned about closures from practice with certain programming languages or other clueless programmers, take a journey to the source (where it all began). And since lambdas and closures come from Lambda Calculus invented by Alonzo Church back in the '30s before first electronic computers even existed, this is the source I'm talking about.

Lambda Calculus is the simplest programming language in the world. The only things you can do in it:?

  • APPLICATION: Applying one expression to another, denoted f x.
    (Think of it as a function call, where f is the function and x is its only parameter)
  • ABSTRACTION: Binds a symbol occurring in an expression to mark that this symbol is just a "slot", a blank box waiting to be filled with value, a "variable" as it were. It is done by prepending a Greek letter ? (lambda), then the symbolic name (e.g. x), then a dot . before the expression. This then converts the expression into a function expecting one parameter.
    For example: ?x.x+2 takes the expression x+2 and tells that the symbol x in this expression is a bound variable – it can be substituted with a value you supply as a parameter.
    Note that the function defined this way is anonymous – it doesn't have a name, so you can't refer to it yet, but you can immediately call it (remember application?) by supplying it the parameter it is waiting for, like this: (?x.x+2) 7. Then the expression (in this case a literal value) 7 is substituted as x in the subexpression x+2 of the applied lambda, so you get 7+2, which then reduces to 9 by common arithmetics rules.

So we've solved one of the mysteries:
lambda is the anonymous function from the example above, ?x.x+2.


In different programming languages, the syntax for functional abstraction (lambda) may differ. For example, in JavaScript it looks like this:

function(x) { return x+2; }

and you can immediately apply it to some parameter like this:

(function(x) { return x+2; })(7)

or you can store this anonymous function (lambda) into some variable:

var f = function(x) { return x+2; }

which effectively gives it a name f, allowing you to refer to it and call it multiple times later, e.g.:

alert(  f(7) + f(10)  );   // should print 21 in the message box

But you didn't have to name it. You could call it immediately:

alert(  function(x) { return x+2; } (7)  );  // should print 9 in the message box

In LISP, lambdas are made like this:

(lambda (x) (+ x 2))

and you can call such a lambda by applying it immediately to a parameter:

(  (lambda (x) (+ x 2))  7  )


OK, now it's time to solve the other mystery: what is a closure. In order to do that, let's talk about symbols (variables) in lambda expressions.

As I said, what the lambda abstraction does is binding a symbol in its subexpression, so that it becomes a substitutible parameter. Such a symbol is called bound. But what if there are other symbols in the expression? For example: ?x.x/y+2. In this expression, the symbol x is bound by the lambda abstraction ?x. preceding it. But the other symbol, y, is not bound – it is free. We don't know what it is and where it comes from, so we don't know what it means and what value it represents, and therefore we cannot evaluate that expression until we figure out what y means.

In fact, the same goes with the other two symbols, 2 and +. It's just that we are so familiar with these two symbols that we usually forget that the computer doesn't know them and we need to tell it what they mean by defining them somewhere, e.g. in a library or the language itself.

You can think of the free symbols as defined somewhere else, outside the expression, in its "surrounding context", which is called its environment. The environment might be a bigger expression that this expression is a part of (as Qui-Gon Jinn said: "There's always a bigger fish" ;) ), or in some library, or in the language itself (as a primitive).

This lets us divide lambda expressions into two categories:

  • CLOSED expressions: every symbol that occurs in these expressions is bound by some lambda abstraction. In other words, they are self-contained; they don't require any surrounding context to be evaluated. They are also called combinators.
  • OPEN expressions: some symbols in these expressions are not bound – that is, some of the symbols occurring in them are free and they require some external information, and thus they cannot be evaluated until you supply the definitions of these symbols.

You can CLOSE an open lambda expression by supplying the environment, which defines all these free symbols by binding them to some values (which may be numbers, strings, anonymous functions aka lambdas, whatever…).

And here comes the closure part:
The closure of a lambda expression is this particular set of symbols defined in the outer context (environment) that give values to the free symbols in this expression, making them non-free anymore. It turns an open lambda expression, which still contains some "undefined" free symbols, into a closed one, which doesn't have any free symbols anymore.

For example, if you have the following lambda expression: ?x.x/y+2, the symbol x is bound, while the symbol y is free, therefore the expression is open and cannot be evaluated unless you say what y means (and the same with + and 2, which are also free). But suppose that you also have an environment like this:

{  y: 3,
+: [built-in addition],
2: [built-in number],
q: 42,
w: 5  }

This environment supplies definitions for all the "undefined" (free) symbols from our lambda expression (y, +, 2), and several extra symbols (q, w). The symbols that we need to be defined are this subset of the environment:

{  y: 3,
+: [built-in addition],
2: [built-in number]  }

and this is precisely the closure of our lambda expression :>

In other words, it closes an open lambda expression. This is where the name closure came from in the first place, and this is why so many people's answers in this thread are not quite correct :P


So why are they mistaken? Why do so many of them say that closures are some data structures in memory, or some features of the languages they use, or why do they confuse closures with lambdas? :P

Well, the corporate marketoids of Sun/Oracle, Microsoft, Google etc. are to blame, because that's what they called these constructs in their languages (Java, C#, Go etc.). They often call "closures" what are supposed to be just lambdas. Or they call "closures" a particular technique they used to implement lexical scoping, that is, the fact that a function can access the variables that were defined in its outer scope at the time of its definition. They often say that the function "encloses" these variables, that is, captures them into some data structure to save them from being destroyed after the outer function finishes executing. But this is just made-up post factum "folklore etymology" and marketing, which only makes things more confusing, because every language vendor uses its own terminology.

And it's even worse because of the fact that there's always a bit of truth in what they say, which does not allow you to easily dismiss it as false :P Let me explain:

If you want to implement a language that uses lambdas as first-class citizens, you need to allow them to use symbols defined in their surrounding context (that is, to use free variables in your lambdas). And these symbols must be there even when the surrounding function returns. The problem is that these symbols are bound to some local storage of the function (usually on the call stack), which won't be there anymore when the function returns. Therefore, in order for a lambda to work the way you expect, you need to somehow "capture" all these free variables from its outer context and save them for later, even when the outer context will be gone. That is, you need to find the closure of your lambda (all these external variables it uses) and store it somewhere else (either by making a copy, or by preparing space for them upfront, somewhere else than on the stack). The actual method you use to achieve this goal is an "implementation detail" of your language. What's important here is the closure, which is the set of free variables from the environment of your lambda that need to be saved somewhere.

It didn't took too long for people to start calling the actual data structure they use in their language's implementations to implement closure as the "closure" itself. The structure usually looks something like this:

Closure {
   [pointer to the lambda function's machine code],
   [pointer to the lambda function's environment]
}

and these data structures are being passed around as parameters to other functions, returned from functions, and stored in variables, to represent lambdas, and allowing them to access their enclosing environment as well as the machine code to run in that context. But it's just a way (one of many) to implement closure, not the closure itself.

As I explained above, the closure of a lambda expression is the subset of definitions in its environment that give values to the free variables contained in that lambda expression, effectively closing the expression (turning an open lambda expression, which cannot be evaluated yet, into a closed lambda expression, which can then be evaluated, since all the symbols contained in it are now defined).

Anything else is just a "cargo cult" and "voo-doo magic" of programmers and language vendors unaware of the real roots of these notions.

I hope that answers your questions. But if you had any follow-up questions, feel free to ask them in the comments, and I'll try to explain it better.

MySQL : transaction within a stored procedure

Take a look at http://dev.mysql.com/doc/refman/5.0/en/declare-handler.html

Basically you declare error handler which will call rollback

START TRANSACTION;

DECLARE EXIT HANDLER FOR SQLEXCEPTION 
    BEGIN
        ROLLBACK;
        EXIT PROCEDURE;
    END;
COMMIT;

jQuery textbox change event doesn't fire until textbox loses focus?

Try the below Code:

$("#textbox").on('change keypress paste', function() {
  console.log("Handler for .keypress() called.");
});

ASP.NET MVC View Engine Comparison

I think this list should also include samples of each view engine so users can get a flavour of each without having to visit every website.

Pictures say a thousand words and markup samples are like screenshots for view engines :) So here's one from my favourite Spark View Engine

<viewdata products="IEnumerable[[Product]]"/>
<ul if="products.Any()">
  <li each="var p in products">${p.Name}</li>
</ul>
<else>
  <p>No products available</p>
</else>