SyntaxFix

Programs & Examples On #Trojan

A trojan is a malicious program which is injected to or poses as a known application.

What is Persistence Context?

A persistent context represents the entities which hold data and are qualified to be persisted in some persistent storage like a database. Once we commit a transaction under a session which has these entities attached with, Hibernate flushes the persistent context and changes(insert/save, update or delete) on them are persisted in the persistent storage.

Convert seconds value to hours minutes seconds?

With Java 8, you can easily achieve time in String format from long seconds like,

LocalTime.ofSecondOfDay(86399L)

Here, given value is max allowed to convert (upto 24 hours) and result will be 

23:59:59

Pros : 1) No need to convert manually and to append 0 for single digit

Cons : work only for up to 24 hours

Splitting String and put it on int array

Java 8 offers a streams-based alternative to manual iteration:

int[] intArray = Arrays.stream(input.split(","))
    .mapToInt(Integer::parseInt)
    .toArray();

Be prepared to catch NumberFormatException if it's possible for the input to contain character sequences that cannot be converted to an integer.

There has been an error processing your request, Error log record number

When magento mode is default it showws such error Change magento mode to developer with

php bin/magento deploy:mode:set developer

then check your error on your browser and resolve that

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

I know it's an old thread I worked with above answer and had to add:

header('Access-Control-Allow-Methods: GET, POST, PUT');

So my header looks like:

header('Access-Control-Allow-Origin: *');
header("Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept");
header('Access-Control-Allow-Methods: GET, POST, PUT');

And the problem was fixed.

Validating Phone Numbers Using Javascript

 
<html>
<title>Practice Session</title>
<body>           
<form name="RegForm" onsubmit="return validate()" method="post">  
<p>Name: <input type="text" name="Name"> </p><br>        
<p>Contact: <input type="text" name="Telephone"> </p><br>   
<p><input type="submit" value="send" name="Submit"></p>          
</form> 
</body>
<script> 
function validate()                                    
{ 
var name = document.forms["RegForm"]["Name"];                
var phone = document.forms["RegForm"]["Telephone"];  
if (name.value == "")                                  
{ 
window.alert("Please enter your name."); 
name.focus();
return false;
}
else if(isNaN(name.value) /*"%d[10]"*/)
{
alert("name confirmed");
}
else{ 
window.alert("please enter character"); 
}   
if (phone.value == "")                           
{ 
window.alert("Please enter your telephone number."); 
phone.focus();
return false; 
} 
else if(!isNaN(phone.value) /*phone.value == isNaN(phone.value)*/)
{
alert("number confirmed");
}
else{
window.alert("please enter numbers only");
}   
}
</script> 
</html>

How to run php files on my computer

You have to run a web server (e.g. Apache) and browse to your localhost, mostly likely on port 80.

What you really ought to do is install an all-in-one package like XAMPP, it bundles Apache, MySQL PHP, and Perl (if you were so inclined) as well as a few other tools that work with Apache and MySQL - plus it's cross platform (that's what the 'X' in 'XAMPP' stands for).

Once you install XAMPP (and there is an installer, so it shouldn't be hard) open up the control panel for XAMPP and then click the "Start" button next to Apache - note that on applications that require a database, you'll also need to start MySQL (and you'll be able to interface with it through phpMyAdmin). Once you've started Apache, you can browse to http://localhost.

Again, regardless of whether or not you choose XAMPP (which I would recommend), you should just have to start Apache.

Difference between string and StringBuilder in C#

A String (System.String) is a type defined inside the .NET framework. The String class is not mutable. This means that every time you do an action to an System.String instance, the .NET compiler create a new instance of the string. This operation is hidden to the developer.

A System.Text.StringBuilder is class that represents a mutable string. This class provides some useful methods that make the user able to manage the String wrapped by the StringBuilder. Notice that all the manipulations are made on the same StringBuilder instance.

Microsoft encourages the use of StringBuilder because it is more effective in terms of memory usage.

How to display tables on mobile using Bootstrap?

You might also consider trying one of these approaches, since larger tables aren't exactly friendly on mobile even if it works:

http://elvery.net/demo/responsive-tables/

I'm partial to 'No More Tables' but that obviously depends on your application.

Show Error on the tip of the Edit Text Android

Simple way to implement this thing following this method

1st initial the EditText Field

  EditText editText = findViewById(R.id.editTextField);

When you done initialization. Now time to keep the imputed value in a variable

  final String userInput = editText.getText().toString();

Now Time to check the condition whether user fulfilled or not

  if (userInput.isEmpty()){
           editText.setError("This field need to fill up");
       
        }else{
         //Do what you want to do
      }

Here is an example how I did with my project

  private void sendMail() {
       final String userMessage = etMessage.getText().toString();
          if (userMessage.isEmpty()) {

            etMessage.setError("Write to us");

    }else{
       Toast.makeText(this, "You write to us"+etMessage, Toast.LENGTH_SHORT).show();
      }
   }

Hope it will help you.

HappyCoding

Is there a max array length limit in C++?

As many excellent answers noted, there are a lot of limits that depend on your version of C++ compiler, operating system and computer characteristics. However, I suggest the following script on Python that checks the limit on your machine.

It uses binary search and on each iteration checks if the middle size is possible by creating a code that attempts to create an array of the size. The script tries to compile it (sorry, this part works only on Linux) and adjust binary search depending on the success. Check it out:

import os

cpp_source = 'int a[{}]; int main() {{ return 0; }}'

def check_if_array_size_compiles(size):
        #  Write to file 1.cpp
        f = open(name='1.cpp', mode='w')
        f.write(cpp_source.format(m))
        f.close()
        #  Attempt to compile
        os.system('g++ 1.cpp 2> errors')
        #  Read the errors files
        errors = open('errors', 'r').read()
        #  Return if there is no errors
        return len(errors) == 0

#  Make a binary search. Try to create array with size m and
#  adjust the r and l border depending on wheather we succeeded
#  or not
l = 0
r = 10 ** 50
while r - l > 1:
        m = (r + l) // 2
        if check_if_array_size_compiles(m):
                l = m
        else:
                r = m

answer = l + check_if_array_size_compiles(r)
print '{} is the maximum avaliable length'.format(answer)

You can save it to your machine and launch it, and it will print the maximum size you can create. For my machine it is 2305843009213693951.

Redirecting from HTTP to HTTPS with PHP

On my AWS beanstalk server, I don't see $_SERVER['HTTPS'] variable. I do see $_SERVER['HTTP_X_FORWARDED_PROTO'] which can be either 'http' or 'https' so if you're hosting on AWS, use this:

if ($_SERVER['HTTP_HOST'] != 'localhost' and $_SERVER['HTTP_X_FORWARDED_PROTO'] != "https") {
    $location = 'https://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
    header('HTTP/1.1 301 Moved Permanently');
    header('Location: ' . $location);
    exit;
}

How do you use the Immediate Window in Visual Studio?

The Immediate window is used to debug and evaluate expressions, execute statements, print variable values, and so forth. It allows you to enter expressions to be evaluated or executed by the development language during debugging.

To display Immediate Window, choose Debug >Windows >Immediate or press Ctrl-Alt-I

enter image description here

Here is an example with Immediate Window:

int Sum(int x, int y) { return (x + y);}
void main(){
int a, b, c;
a = 5;
b = 7;
c = Sum(a, b);
char temp = getchar();}

add breakpoint

enter image description here

call commands

enter image description here

https://msdn.microsoft.com/en-us/library/f177hahy.aspx

How to refresh table contents in div using jquery/ajax

You can load HTML page partial, in your case is everything inside div#mytable.

setTimeout(function(){
   $( "#mytable" ).load( "your-current-page.html #mytable" );
}, 2000); //refresh every 2 seconds

more information read this http://api.jquery.com/load/

Update Code (if you don't want it auto-refresh)

<button id="refresh-btn">Refresh Table</button>

<script>
$(document).ready(function() {

   function RefreshTable() {
       $( "#mytable" ).load( "your-current-page.html #mytable" );
   }

   $("#refresh-btn").on("click", RefreshTable);

   // OR CAN THIS WAY
   //
   // $("#refresh-btn").on("click", function() {
   //    $( "#mytable" ).load( "your-current-page.html #mytable" );
   // });


});
</script>

Add Favicon with React and Webpack

Another alternative is

npm install react-favicon

And in your application you would just do:

   import Favicon from 'react-favicon';
   //other codes

    ReactDOM.render(
        <div>
            <Favicon url="/path/to/favicon.ico"/>
            // do other stuff here
        </div>
        , document.querySelector('.react'));

Getting the IP address of the current machine using Java

Posting here tested IP ambiguity workaround code from https://issues.apache.org/jira/browse/JCS-40 (InetAddress.getLocalHost() ambiguous on Linux systems):

/**
 * Returns an <code>InetAddress</code> object encapsulating what is most likely the machine's LAN IP address.
 * <p/>
 * This method is intended for use as a replacement of JDK method <code>InetAddress.getLocalHost</code>, because
 * that method is ambiguous on Linux systems. Linux systems enumerate the loopback network interface the same
 * way as regular LAN network interfaces, but the JDK <code>InetAddress.getLocalHost</code> method does not
 * specify the algorithm used to select the address returned under such circumstances, and will often return the
 * loopback address, which is not valid for network communication. Details
 * <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4665037">here</a>.
 * <p/>
 * This method will scan all IP addresses on all network interfaces on the host machine to determine the IP address
 * most likely to be the machine's LAN address. If the machine has multiple IP addresses, this method will prefer
 * a site-local IP address (e.g. 192.168.x.x or 10.10.x.x, usually IPv4) if the machine has one (and will return the
 * first site-local address if the machine has more than one), but if the machine does not hold a site-local
 * address, this method will return simply the first non-loopback address found (IPv4 or IPv6).
 * <p/>
 * If this method cannot find a non-loopback address using this selection algorithm, it will fall back to
 * calling and returning the result of JDK method <code>InetAddress.getLocalHost</code>.
 * <p/>
 *
 * @throws UnknownHostException If the LAN address of the machine cannot be found.
 */
private static InetAddress getLocalHostLANAddress() throws UnknownHostException {
    try {
        InetAddress candidateAddress = null;
        // Iterate all NICs (network interface cards)...
        for (Enumeration ifaces = NetworkInterface.getNetworkInterfaces(); ifaces.hasMoreElements();) {
            NetworkInterface iface = (NetworkInterface) ifaces.nextElement();
            // Iterate all IP addresses assigned to each card...
            for (Enumeration inetAddrs = iface.getInetAddresses(); inetAddrs.hasMoreElements();) {
                InetAddress inetAddr = (InetAddress) inetAddrs.nextElement();
                if (!inetAddr.isLoopbackAddress()) {

                    if (inetAddr.isSiteLocalAddress()) {
                        // Found non-loopback site-local address. Return it immediately...
                        return inetAddr;
                    }
                    else if (candidateAddress == null) {
                        // Found non-loopback address, but not necessarily site-local.
                        // Store it as a candidate to be returned if site-local address is not subsequently found...
                        candidateAddress = inetAddr;
                        // Note that we don't repeatedly assign non-loopback non-site-local addresses as candidates,
                        // only the first. For subsequent iterations, candidate will be non-null.
                    }
                }
            }
        }
        if (candidateAddress != null) {
            // We did not find a site-local address, but we found some other non-loopback address.
            // Server might have a non-site-local address assigned to its NIC (or it might be running
            // IPv6 which deprecates the "site-local" concept).
            // Return this non-loopback candidate address...
            return candidateAddress;
        }
        // At this point, we did not find a non-loopback address.
        // Fall back to returning whatever InetAddress.getLocalHost() returns...
        InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
        if (jdkSuppliedAddress == null) {
            throw new UnknownHostException("The JDK InetAddress.getLocalHost() method unexpectedly returned null.");
        }
        return jdkSuppliedAddress;
    }
    catch (Exception e) {
        UnknownHostException unknownHostException = new UnknownHostException("Failed to determine LAN address: " + e);
        unknownHostException.initCause(e);
        throw unknownHostException;
    }
}

Animate an element's width from 0 to 100%, with it and it's wrapper being only as wide as they need to be, without a pre-set width, in CSS3 or jQuery

Please check following snippet

_x000D_
_x000D_ 
 /* DEBUG */_x000D_
.lwb-col {_x000D_
    transition: box-shadow 0.5s ease;_x000D_
}_x000D_
.lwb-col:hover{_x000D_
    box-shadow: 0 15px 30px -4px rgba(136, 155, 166, 0.4);_x000D_
 _x000D_
}_x000D_
_x000D_
_x000D_
.lwb-col--link {_x000D_
    font-weight: 500;_x000D_
  position: relative;_x000D_
  display: inline-block;_x000D_
}_x000D_
.lwb-col--link::after{_x000D_
    border-bottom: 2px solid;_x000D_
    bottom: -3px;_x000D_
    content: "";_x000D_
    display: block;_x000D_
    left: 0;_x000D_
    position: absolute;_x000D_
    width: 100%;_x000D_
    color: #E5E9EC;_x000D_
_x000D_
}_x000D_
.lwb-col--link::before{_x000D_
    border-bottom: 2px solid;_x000D_
    bottom: -3px;_x000D_
    content: "";_x000D_
    display: block;_x000D_
    left: 0;_x000D_
    position: absolute;_x000D_
    width: 100%;_x000D_
    color: #57B0FB;_x000D_
    transform: scaleX(0);_x000D_
    _x000D_
_x000D_
}_x000D_
.lwb-col:hover .lwb-col--link::before {_x000D_
    border-color: #57B0FB;_x000D_
    display: block;_x000D_
    z-index: 2;_x000D_
    transition: transform 0.3s;_x000D_
    transform: scaleX(1);_x000D_
    transform-origin: left center;_x000D_
}
_x000D_ 
<div class="lwb-col">_x000D_
  <h2>Webdesign</h2>_x000D_
  <p>Steigern Sie Ihre Bekanntheit im Web mit individuellem &amp; professionellem Webdesign. Organisierte Codestruktur, sowie perfekte SEO Optimierung und jahrelange Erfahrung sprechen für uns.</p>_x000D_
<span class="lwb-col--link">Mehr erfahren</span>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Check whether an array is empty

I can't replicate that (php 5.3.6):

php > $error = array();
php > $error['something'] = false;
php > $error['somethingelse'] = false;
php > var_dump(empty($error));
bool(false)

php > $error = array();
php > var_dump(empty($error));
bool(true)
php >

exactly where are you doing the empty() call that returns true?

Failed to execute 'btoa' on 'Window': The string to be encoded contains characters outside of the Latin1 range.

I just ran into this problem myself.

First, modify your code slightly:

var download = "<?xml version=\"1.0\" encoding=\"utf-8\"?>"
                  +"<"+this.gamesave.tagName+">"
                  +this.xml.firstChild.innerHTML
                  +"</"+this.gamesave.tagName+">";

this.loader.src = "data:application/x-forcedownload;base64,"+
                  btoa(download);

Then use your favorite web inspector, put a breakpoint on the line of code that assigns this.loader.src, then execute this code:

for (var i = 0; i < download.length; i++) {
  if (download[i].charCodeAt(0) > 255) {
    console.warn('found character ' + download[i].charCodeAt(0) + ' "' + download[i] + '" at position ' + i);
  }
}

Depending on your application, replacing the characters that are out of range may or may not work, since you'll be modifying the data. See the note on MDN about unicode characters with the btoa method:

https://developer.mozilla.org/en-US/docs/Web/API/window.btoa

UICollectionView auto scroll to cell at IndexPath

this seemed to work for me, its similar to another answer but has some distinct differences:

- (void)viewDidLayoutSubviews
{     
   [self.collectionView layoutIfNeeded];
   NSArray *visibleItems = [self.collectionView indexPathsForVisibleItems];
   NSIndexPath *currentItem = [visibleItems objectAtIndex:0];
   NSIndexPath *nextItem = [NSIndexPath indexPathForItem:someInt inSection:currentItem.section];

   [self.collectionView scrollToItemAtIndexPath:nextItem atScrollPosition:UICollectionViewScrollPositionNone animated:YES];
}

How I can get web page's content and save it into the string variable

 
Webclient client = new Webclient();
string content = client.DownloadString(url);

Pass the URL of page who you want to get. You can parse the result using htmlagilitypack.

What are all the different ways to create an object in Java?

Within the Java language, the only way to create an object is by calling its constructor, be it explicitly or implicitly. Using reflection results in a call to the constructor method, deserialization uses reflection to call the constructor, factory methods wrap the call to the constructor to abstract the actual construction and cloning is similarly a wrapped constructor call.

Check if array is empty or null

User JQuery is EmptyObject to check whether array is contains elements or not.

var testArray=[1,2,3,4,5];
var testArray1=[];
console.log(jQuery.isEmptyObject(testArray)); //false
console.log(jQuery.isEmptyObject(testArray1)); //true

Oracle query to fetch column names

I find this one useful in Oracle:

SELECT 
    obj.object_name, 
    atc.column_name, 
    atc.data_type, 
    atc.data_length 
FROM 
    all_tab_columns atc,
    (SELECT 
        * 
     FROM 
         all_objects
     WHERE 
        object_name like 'GL_JE%'
        AND owner = 'GL'
        AND object_type in ('TABLE','VIEW')   
    ) obj
WHERE 
    atc.table_name = obj.object_name
ORDER BY 
    obj.object_name, 
    atc.column_name;

Update an outdated branch against master in a Git repo

Update the master branch, which you need to do regardless.

Then, one of:

  1. Rebase the old branch against the master branch. Solve the merge conflicts during rebase, and the result will be an up-to-date branch that merges cleanly against master.

  2. Merge your branch into master, and resolve the merge conflicts.

  3. Merge master into your branch, and resolve the merge conflicts. Then, merging from your branch into master should be clean.

None of these is better than the other, they just have different trade-off patterns.

I would use the rebase approach, which gives cleaner overall results to later readers, in my opinion, but that is nothing aside from personal taste.

To rebase and keep the branch you would:

git checkout <branch> && git rebase <target>

In your case, check out the old branch, then 

git rebase master

to get it rebuilt against master.

laravel 5.5 The page has expired due to inactivity. Please refresh and try again

This happens because you are using the default CSRV middleware from Laravel's installation. To solve, remove this line from your Kernel.php:

\App\Http\Middleware\VerifyCsrfToken::class,

This is fine if you are build an API. However, if you are building a website this is a security verification, so be aware of its risks.

Query to display all tablespaces in a database and datafiles

In oracle, generally speaking, there are number of facts that I will mention in following section:

  • Each database can have many Schema/User (Logical division).
  • Each database can have many tablespaces (Logical division).
  • A schema is the set of objects (tables, indexes, views, etc) that belong to a user.
  • In Oracle, a user can be considered the same as a schema.
  • A database is divided into logical storage units called tablespaces, which group related logical structures together. For example, tablespaces commonly group all of an application’s objects to simplify some administrative operations. You may have a tablespace for application data and an additional one for application indexes.

Therefore, your question, "to see all tablespaces and datafiles belong to SCOTT" is s bit wrong.

However, there are some DBA views encompass information about all database objects, regardless of the owner. Only users with DBA privileges can access these views: DBA_DATA_FILES, DBA_TABLESPACES, DBA_FREE_SPACE, DBA_SEGMENTS.

So, connect to your DB as sysdba and run query through these helpful views. For example this query can help you to find all tablespaces and their data files that objects of your user are located:

SELECT DISTINCT sgm.TABLESPACE_NAME , dtf.FILE_NAME
FROM DBA_SEGMENTS sgm
JOIN DBA_DATA_FILES dtf ON (sgm.TABLESPACE_NAME = dtf.TABLESPACE_NAME)
WHERE sgm.OWNER = 'SCOTT'

How can I change the Java Runtime Version on Windows (7)?

If you are using windows 10 or windows server 2012, the steps to change the java runtime version is this:

  1. Open regedit using 'Run'
  2. Navigate to HKEY_LOCAL_MACHINE -> SOFTWARE -> JavaSoft -> Java Runtime Environment
  3. Here you will see all the versions of java you installed on your PC. For me I have several versions of java 1.8 installed, so the folder displayed here are 1.8, 1.8.0_162 and 1.8.0_171
  4. Click the '1.8' folder, then double click the JavaHome and RuntimeLib keys, Change the version number inside to whichever Java version you want your PC to run on. For example, if the Value data of the key is 'C:\Program Files\Java\jre1.8.0_171', you can change this to 'C:\Program Files\Java\jre1.8.0_162'.
  5. You can then verify the version change by typing 'java -version' on the command line.

Can constructors throw exceptions in Java?

Yes, it can throw an exception and you can declare that in the signature of the constructor too as shown in the example below:

public class ConstructorTest
{
    public ConstructorTest() throws InterruptedException
    {
        System.out.println("Preparing object....");
        Thread.sleep(1000);
        System.out.println("Object ready");
    }

    public static void main(String ... args)
    {
        try
        {
            ConstructorTest test = new ConstructorTest();
        }
        catch (InterruptedException e)
        {
            System.out.println("Got interrupted...");
        }
    }
}

Starting a shell in the Docker Alpine container

Usually, an Alpine Linux image doesn't contain bash, Instead you can use /bin/ash, /bin/sh, ash or only sh.

/bin/ash

docker run -it --rm alpine /bin/ash

/bin/sh

docker run -it --rm alpine /bin/sh

ash

docker run -it --rm alpine ash

sh

docker run -it --rm alpine sh

I hope this information helps you.

Is it possible to create a remote repo on GitHub from the CLI without opening browser?

For all the Python 2.7.* users. There is a Python wrapper around the Github API that is currently on Version 3, called GitPython. Simply install using easy_install PyGithub or pip install PyGithub.

from github import Github
g = Github(your-email-addr, your-passwd)
repo = g.get_user().user.create_repo("your-new-repos-name")

# Make use of Repository object (repo)

The Repository object docs are here.

Passing an integer by reference in Python

Most cases where you would need to pass by reference are where you need to return more than one value back to the caller. A "best practice" is to use multiple return values, which is much easier to do in Python than in languages like Java.

Here's a simple example:

def RectToPolar(x, y):
    r = (x ** 2 + y ** 2) ** 0.5
    theta = math.atan2(y, x)
    return r, theta # return 2 things at once

r, theta = RectToPolar(3, 4) # assign 2 things at once

How to make g++ search for header files in a specific directory?

 
gcc -I/path -L/path

  • -I /path path to include, gcc will find .h files in this path

  • -L /path contains library files, .a, .so

Check whether a variable is a string in Ruby

I think you are looking for instance_of?. is_a? and kind_of? will return true for instances from derived classes. 

class X < String
end

foo = X.new

foo.is_a? String         # true
foo.kind_of? String      # true
foo.instance_of? String  # false
foo.instance_of? X       # true

Add a summary row with totals

If you are on SQL Server 2008 or later version, you can use the ROLLUP() GROUP BY function:

SELECT
  Type = ISNULL(Type, 'Total'),
  TotalSales = SUM(TotalSales)
FROM atable
GROUP BY ROLLUP(Type)
;

This assumes that the Type column cannot have NULLs and so the NULL in this query would indicate the rollup row, the one with the grand total. However, if the Type column can have NULLs of its own, the more proper type of accounting for the total row would be like in @Declan_K's answer, i.e. using the GROUPING() function:

SELECT
  Type = CASE GROUPING(Type) WHEN 1 THEN 'Total' ELSE Type END,
  TotalSales = SUM(TotalSales)
FROM atable
GROUP BY ROLLUP(Type)
;

How to connect to remote Oracle DB with PL/SQL Developer?

The problem is not the TNS file, in PLSQL Developer, if you don't have the oracle installation, you need to provide the location of the OCI.DLL file.

In PLSQL DEV app go to Tools-Preferences-Oracle/connections-OCI Library.

In my case I put the next address C:\Oracle\InstantClient-win32-11.2.0.1.0\oci.dll.

If have Weblogic app installed, I didnt tried but if you want try to put the next location

C:\Oracle\Middleware\wlserver_10.3\server\adr.

There isn't anything to compare. Nothing to compare, branches are entirely different commit histories

I wanted to copy commit history of "master" branch & overwrite the commit history of "main" branch .
The steps are:-

  1. git checkout master
  2. git branch main master -f
  3. git checkout main
  4. git push

To delete master branch:-

a. Locally:-

  1. git checkout main
  2. git branch -d master

b. Globally:-

  1. git push origin --delete master

Do Upvote it!

How to prevent Google Colab from disconnecting?

Well this is working for me -

run the following code in the console and it will prevent you from disconnecting. Ctrl+ Shift + i to open inspector view . Then go to console.

function ClickConnect(){
    console.log("Working"); 
    document.querySelector("colab-toolbar-button#connect").click() 
}
setInterval(ClickConnect,60000)

How to prevent google colab from disconnecting

How to use delimiter for csv in python

ok, here is what i understood from your question. You are writing a csv file from python but when you are opening that file into some other application like excel or open office they are showing the complete row in one cell rather than each word in individual cell. I am right??

if i am then please try this, 

import csv

with open(r"C:\\test.csv", "wb") as csv_file:
    writer = csv.writer(csv_file, delimiter =",",quoting=csv.QUOTE_MINIMAL)
    writer.writerow(["a","b"])

you have to set the delimiter = ","

Run class in Jar file

This is the right way to execute a .jar, and whatever one class in that .jar should have main() and the following are the parameters to it :

java -DLB="uk" -DType="CLIENT_IND" -jar com.fbi.rrm.rrm-batchy-1.5.jar

How do I generate random number for each row in a TSQL Select?

If you want to generate a random number between 1 and 14 inclusive.

SELECT CONVERT(int, RAND() * (14 - 1) + 1)

OR

SELECT ABS(CHECKSUM(NewId())) % (14 -1) + 1

Compute a confidence interval from sample data

Here a shortened version of shasan's code, calculating the 95% confidence interval of the mean of array a:

import numpy as np, scipy.stats as st

st.t.interval(0.95, len(a)-1, loc=np.mean(a), scale=st.sem(a))

But using StatsModels' tconfint_mean is arguably even nicer:

import statsmodels.stats.api as sms

sms.DescrStatsW(a).tconfint_mean()

The underlying assumptions for both are that the sample (array a) was drawn independently from a normal distribution with unknown standard deviation (see MathWorld or Wikipedia).

For large sample size n, the sample mean is normally distributed, and one can calculate its confidence interval using st.norm.interval() (as suggested in Jaime's comment). But the above solutions are correct also for small n, where st.norm.interval() gives confidence intervals that are too narrow (i.e., "fake confidence"). See my answer to a similar question for more details (and one of Russ's comments here).

Here an example where the correct options give (essentially) identical confidence intervals:

In [9]: a = range(10,14)

In [10]: mean_confidence_interval(a)
Out[10]: (11.5, 9.4457397432391215, 13.554260256760879)

In [11]: st.t.interval(0.95, len(a)-1, loc=np.mean(a), scale=st.sem(a))
Out[11]: (9.4457397432391215, 13.554260256760879)

In [12]: sms.DescrStatsW(a).tconfint_mean()
Out[12]: (9.4457397432391197, 13.55426025676088)

And finally, the incorrect result using st.norm.interval():

In [13]: st.norm.interval(0.95, loc=np.mean(a), scale=st.sem(a))
Out[13]: (10.23484868811834, 12.76515131188166)

Git vs Team Foundation Server

I think, the statement

everyone hates it except me

makes any further discussion waste: when you keep using Git, they will blame you if anything goes wrong.

Apart from this, for me Git has two advantages over a centralized VCS that I appreciate most (as partly described by Rob Sobers):

  • automatic backup of the whole repo: everytime someone pulls from the central repo, he/she gets a full history of the changes. When one repo gets lost: don't worry, take one of those present on every workstation.
  • offline repo access: when I'm working at home (or in an airplane or train), I can see the full history of the project, every single checkin, without starting up my VPN connection to work and can work like I were at work: checkin, checkout, branch, anything.

But as I said: I think that you're fighting a lost battle: when everyone hates Git, don't use Git. It could help you more to know why they hate Git instead of trying them to convince them.

If they simply don't want it 'cause it's new to them and are not willing to learn something new: are you sure that you will do successful development with that staff?

Does really every single person hate Git or are they influenced by some opinion leaders? Find the leaders and ask them what's the problem. Convince them and you'll convince the rest of the team.

If you cannot convince the leaders: forget about using Git, take the TFS. Will make your life easier.

How do you get the length of a string?

The easiest way: 

$('#selector').val().length

connecting to phpMyAdmin database with PHP/MySQL

 
$db = new mysqli('Server_Name', 'Name', 'password', 'database_name');

Where to find Application Loader app in Mac?

Now you can upload your app binary with the Transporter app.

You can download Transporter from Mac AppStore Here

Here apple mentioned its used for uploading.

How do I center align horizontal <UL> menu?

Here's a good article on how to do it in a pretty rock-solid way, without any hacks and full cross-browser support. Works for me:

--> http://matthewjamestaylor.com/blog/beautiful-css-centered-menus-no-hacks-full-cross-browser-support

undefined reference to `WinMain@16'

This error occurs when the linker can't find WinMain function, so it is probably missing. In your case, you are probably missing main too.

Consider the following Windows API-level program:

#define NOMINMAX
#include <windows.h>

int main()
{
    MessageBox( 0, "Blah blah...", "My Windows app!", MB_SETFOREGROUND );
}

Now let's build it using GNU toolchain (i.e. g++), no special options. Here gnuc is just a batch file that I use for that. It only supplies options to make g++ more standard:

C:\test> gnuc x.cpp

C:\test> objdump -x a.exe | findstr /i "^subsystem"
Subsystem               00000003        (Windows CUI)

C:\test> _

This means that the linker by default produced a console subsystem executable. The subsystem value in the file header tells Windows what services the program requires. In this case, with console system, that the program requires a console window.

This also causes the command interpreter to wait for the program to complete.

Now let's build it with GUI subsystem, which just means that the program does not require a console window:

C:\test> gnuc x.cpp -mwindows

C:\test> objdump -x a.exe | findstr /i "^subsystem"
Subsystem               00000002        (Windows GUI)

C:\test> _

Hopefully that's OK so far, although the -mwindows flag is just semi-documented.

Building without that semi-documented flag one would have to more specifically tell the linker which subsystem value one desires, and some Windows API import libraries will then in general have to be specified explicitly:

C:\test> gnuc x.cpp -Wl,-subsystem,windows

C:\test> objdump -x a.exe | findstr /i "^subsystem"
Subsystem               00000002        (Windows GUI)

C:\test> _

That worked fine, with the GNU toolchain.

But what about the Microsoft toolchain, i.e. Visual C++?

Well, building as a console subsystem executable works fine:

C:\test> msvc x.cpp user32.lib
x.cpp

C:\test> dumpbin /headers x.exe | find /i "subsystem" | find /i "Windows"
               3 subsystem (Windows CUI)

C:\test> _

However, with Microsoft's toolchain building as GUI subsystem does not work by default:

C:\test> msvc x.cpp user32.lib /link /subsystem:windows
x.cpp
LIBCMT.lib(wincrt0.obj) : error LNK2019: unresolved external symbol _WinMain@16 referenced in function ___tmainCRTStartu
p
x.exe : fatal error LNK1120: 1 unresolved externals

C:\test> _

Technically this is because Microsoft’s linker is non-standard by default for GUI subsystem. By default, when the subsystem is GUI, then Microsoft's linker uses a runtime library entry point, the function where the machine code execution starts, called winMainCRTStartup, that calls Microsoft's non-standard WinMain instead of standard main.

No big deal to fix that, though.

All you have to do is to tell Microsoft's linker which entry point to use, namely mainCRTStartup, which calls standard main:

C:\test> msvc x.cpp user32.lib /link /subsystem:windows /entry:mainCRTStartup
x.cpp

C:\test> dumpbin /headers x.exe | find /i "subsystem" | find /i "Windows"
               2 subsystem (Windows GUI)

C:\test> _

No problem, but very tedious. And so arcane and hidden that most Windows programmers, who mostly only use Microsoft’s non-standard-by-default tools, do not even know about it, and mistakenly think that a Windows GUI subsystem program “must” have non-standard WinMain instead of standard main. In passing, with C++0x Microsoft will have a problem with this, since the compiler must then advertize whether it's free-standing or hosted (when hosted it must support standard main).

Anyway, that's the reason why g++ can complain about WinMain missing: it's a silly non-standard startup function that Microsoft's tools require by default for GUI subsystem programs.

But as you can see above, g++ has no problem with standard main even for a GUI subsystem program.

So what could be the problem?

Well, you are probably missing a main. And you probably have no (proper) WinMain either! And then g++, after having searched for main (no such), and for Microsoft's non-standard WinMain (no such), reports that the latter is missing.

Testing with an empty source:

C:\test> type nul >y.cpp

C:\test> gnuc y.cpp -mwindows
c:/program files/mingw/bin/../lib/gcc/mingw32/4.4.1/../../../libmingw32.a(main.o):main.c:(.text+0xd2): undefined referen
ce to `WinMain@16'
collect2: ld returned 1 exit status

C:\test> _

What is the meaning of # in URL and how can I use that?

This is known as the "fragment identifier" and is typically used to identify a portion of an HTML document that sits within a fully qualified URL:

Fragment Identifier Wiki Page

Which comes first in a 2D array, rows or columns?

All depends on your visualization of the array. Rows and Columns are properties of visualization (probably in your imagination) of the array, not the array itself.

It's exactly the same as asking is number "5" red or green?

I could draw it red, I could draw it greed right? Color is not an integral property of a number. In the same way representing 2D array as a grid of rows and columns is not necessary for existence of this array.

2D array has just first dimention and second dimention, everything related to visualizing those is purely your flavour.

When I have char array char[80][25], I may like to print it on console rotated so that I have 25 rows of 80 characters that fits the screen without scroll.

I'll try to provide viable example when representing 2D array as rows and columns doesn't make sense at all: Let's say I need an array of 1 000 000 000 integers. My machine has 8GB of RAM, so I have enough memory for this, but if you try executing var a = new int[1000000000], you'll most likely get OutOfMemory exception. That's because of memory fragmentation - there is no consecutive block of memory of this size. Instead you you can create 2D array 10 000 x 100 000 with your values. Logically it is 1D array, so you'd like to draw and imagine it as a single sequence of values, but due to technical implementation it is 2D.

invalid byte sequence for encoding "UTF8"

If you need to store UTF8 data in your database, you need a database that accepts UTF8. You can check the encoding of your database in pgAdmin. Just right-click the database, and select "Properties".

But that error seems to be telling you there's some invalid UTF8 data in your source file. That means that the copy utility has detected or guessed that you're feeding it a UTF8 file.

If you're running under some variant of Unix, you can check the encoding (more or less) with the file utility.

$ file yourfilename
yourfilename: UTF-8 Unicode English text

(I think that will work on Macs in the terminal, too.) Not sure how to do that under Windows.

If you use that same utility on a file that came from Windows systems (that is, a file that's not encoded in UTF8), it will probably show something like this:

$ file yourfilename
yourfilename: ASCII text, with CRLF line terminators

If things stay weird, you might try to convert your input data to a known encoding, to change your client's encoding, or both. (We're really stretching the limits of my knowledge about encodings.)

You can use the iconv utility to change encoding of the input data.

iconv -f original_charset -t utf-8 originalfile > newfile

You can change psql (the client) encoding following the instructions on Character Set Support. On that page, search for the phrase "To enable automatic character set conversion".

How can I limit the visible options in an HTML <select> dropdown?

You can use the size attribute to make the <select> appear as a box instead of a dropdown. The number you use in the size attribute defines how many options are visible in the box without scrolling.

<select size="5">
    <option>1</option>
    <option>2</option>
    <option>3</option>
    <option>4</option>
    <option>5</option>
    <option>6</option>
    <option>7</option>
    <option>8</option>
    <option>9</option>
    <option>10</option>
    <option>11</option>
    <option>12</option>
</select>

You can’t apply this to a <select> and have it still appear as a drop-down list though. The browser/operating system will decide how many options should be displayed for drop-down lists, unless you use HTML, CSS and JavaScript to create a fake dropdown list.

makefiles - compile all c files at once

You need to take out your suffix rule (%.o: %.c) in favour of a big-bang rule. Something like this:

LIBS  = -lkernel32 -luser32 -lgdi32 -lopengl32
CFLAGS = -Wall

OBJ = 64bitmath.o    \
      monotone.o     \
      node_sort.o    \
      planesweep.o   \
      triangulate.o  \
      prim_combine.o \
      welding.o      \
      test.o         \
      main.o

SRCS = $(OBJ:%.o=%.c)

test: $(SRCS)
    gcc -o $@  $(CFLAGS) $(LIBS) $(SRCS)

If you're going to experiment with GCC's whole-program optimization, make sure that you add the appropriate flag to CFLAGS, above.

On reading through the docs for those flags, I see notes about link-time optimization as well; you should investigate those too.

Minimum 6 characters regex expression

Something along the lines of this?

<asp:TextBox id="txtUsername" runat="server" />

<asp:RegularExpressionValidator
    id="RegularExpressionValidator1"
    runat="server"
    ErrorMessage="Field not valid!"
    ControlToValidate="txtUsername"
    ValidationExpression="[0-9a-zA-Z]{6,}" />

Download file from web in Python 3

I hope I understood the question right, which is: how to download a file from a server when the URL is stored in a string type?

I download files and save it locally using the below code:

import requests

url = 'https://www.python.org/static/img/python-logo.png'
fileName = 'D:\Python\dwnldPythonLogo.png'
req = requests.get(url)
file = open(fileName, 'wb')
for chunk in req.iter_content(100000):
    file.write(chunk)
file.close()

How to clear the logs properly for a Docker container?

To remove/clear docker container logs we can use below command

$(docker inspect container_id|grep "LogPath"|cut -d """ -f4) or $(docker inspect container_name|grep "LogPath"|cut -d """ -f4)

Change image source with JavaScript

You've got a few changes (this assumes you indeed still want to change the image with an ID of IMG, if not use Shadow Wizard's solution).

Remove a.src and replace with a:

<script type="text/javascript">
function changeImage(a) {
    document.getElementById("img").src=a;
}
</script>

Change your onclick attributes to include a string of the new image source instead of a literal:

onclick='changeImage( "1772031_29_b.jpg" );'

Notice: Undefined offset: 0 in

You are asking for the value at key 0 of $votes. It is an array that does not contain that key.

The array $votes is not set, so when PHP is trying to access the key 0 of the array, it encounters an undefined offset for [0] and [1] and throws the error.

If you have an array:

$votes = array('1','2','3');

We can now access:

$votes[0];
$votes[1];
$votes[2];

If we try and access:

$votes[3];

We will get the error "Notice: Undefined offset: 3"

To prevent a memory leak, the JDBC Driver has been forcibly unregistered

I was having a similar problem, but additionally I was getting a Java Heap Space error anytime I modified/saved JSP pages with Tomcat server running, therefore the context were not fully recharged.

My versions were Apache Tomcat 6.0.29 and JDK 6u12.

Upgrading JDK to 6u21 as suggested in References section of URL http://wiki.apache.org/tomcat/MemoryLeakProtection solved the Java Heap Space problem (context now reloads OK) although JDBC Driver error still appears.

How to compile without warnings being treated as errors?

-Wall and -Werror compiler options can cause it, please check if those are used in compiler settings.

Can't build create-react-app project with custom PUBLIC_URL

Not sure why you aren't able to set it. In the source, PUBLIC_URL takes precedence over homepage

const envPublicUrl = process.env.PUBLIC_URL;
...
const getPublicUrl = appPackageJson =>
  envPublicUrl || require(appPackageJson).homepage;

You can try setting breakpoints in their code to see what logic is overriding your environment variable.

Using `date` command to get previous, current and next month

the following will do:

date -d "$(date +%Y-%m-1) -1 month" +%-m
date -d "$(date +%Y-%m-1) 0 month" +%-m
date -d "$(date +%Y-%m-1) 1 month" +%-m

or as you need:

LAST_MONTH=`date -d "$(date +%Y-%m-1) -1 month" +%-m`
NEXT_MONTH=`date -d "$(date +%Y-%m-1) 1 month" +%-m`
THIS_MONTH=`date -d "$(date +%Y-%m-1) 0 month" +%-m`

you asked for output like 9,10,11, so I used the %-m

%m (without -) will produce output like 09,... (leading zero)

this also works for more/less than 12 months:

date -d "$(date +%Y-%m-1) -13 month" +%-m

just try

date -d "$(date +%Y-%m-1) -13 month"

to see full result

Difference between logger.info and logger.debug

Just a clarification about the set of all possible levels, that are:

ALL < TRACE < DEBUG < INFO < WARN < ERROR < FATAL < OFF

How to use if statements in underscore.js templates?

To check for null values you could use _.isNull from official documentation

isNull_.isNull(object)

Returns true if the value of object is null.

_.isNull(null);
=> true
_.isNull(undefined);
=> false

Simulate Keypress With jQuery

The keypress event from jQuery is meant to do this sort of work. You can trigger the event by passing a string "keypress" to .trigger(). However to be more specific you can actually pass a jQuery.Event object (specify the type as "keypress") as well and provide any properties you want such as the keycode being the spacebar.

http://docs.jquery.com/Events/trigger#eventdata

Read the above documentation for more details.

Entity Framework Refresh context?

The best way to refresh entities in your context is to dispose your context and create a new one.

If you really need to refresh some entity and you are using Code First approach with DbContext class, you can use

    public static void ReloadEntity<TEntity>(
        this DbContext context, 
        TEntity entity)
        where TEntity : class
    {
        context.Entry(entity).Reload();
    }

To reload collection navigation properties, you can use

    public static void ReloadNavigationProperty<TEntity, TElement>(
        this DbContext context, 
        TEntity entity, 
        Expression<Func<TEntity, ICollection<TElement>>> navigationProperty)
        where TEntity : class
        where TElement : class
    {
        context.Entry(entity).Collection<TElement>(navigationProperty).Query();
    }

Reference: https://msdn.microsoft.com/en-us/library/system.data.entity.infrastructure.dbentityentry.reload(v=vs.113).aspx#M:System.Data.Entity.Infrastructure.DbEntityEntry.Reload

Prolog "or" operator, query

you can 'invoke' alternative bindings on Y this way:

...registered(X, Y), (Y=ct101; Y=ct102; Y=ct103).

Note the parenthesis are required to keep the correct execution control flow. The ;/2 it's the general or operator. For your restricted use you could as well choice the more idiomatic

...registered(X, Y), member(Y, [ct101,ct102,ct103]).

that on backtracking binds Y to each member of the list.

edit I understood with a delay your last requirement. If you want that Y match all 3 values the or is inappropriate, use instead

...registered(X, ct101), registered(X, ct102), registered(X, ct103).

or the more compact

...findall(Y, registered(X, Y), L), sort(L, [ct101,ct102,ct103]).

findall/3 build the list in the very same order that registered/2 succeeds. Then I use sort to ensure the matching.

...setof(Y, registered(X, Y), [ct101,ct102,ct103]).

setof/3 also sorts the result list

What are the rules for casting pointers in C?

You have a pointer to a char. So as your system knows, on that memory address there is a char value on sizeof(char) space. When you cast it up to int*, you will work with data of sizeof(int), so you will print your char and some memory-garbage after it as an integer.

How to compile C programming in Windows 7?

Compiling Programs on Windows 7:

You have to download configured Borland Compiler from http://www.4shared.com/get/Gs41_5yA/borland_for_graphics.html or http://dwij.co.in/graphics-c-programming-for-windows-7-borland-compiler/.

Put your Borland’s ‘bin’ folder into Environmental Variables.
Now go inside folder ‘bin’ & edit file bcc32.cfg as per your folder structure. This file contains settings of headers & libraries.

-I"D:\Borland\include;"
-L"D:\Borland\lib;D:\Borland\Lib\PSDK"

Now create any C/C++ Program say myprogram.cpp
Use following command to compile this bunch of code:

F:\>bcc32 myprogram.cpp

When or Why to use a "SET DEFINE OFF" in Oracle Database

By default, SQL Plus treats '&' as a special character that begins a substitution string. This can cause problems when running scripts that happen to include '&' for other reasons:

SQL> insert into customers (customer_name) values ('Marks & Spencers Ltd');
Enter value for spencers: 
old   1: insert into customers (customer_name) values ('Marks & Spencers Ltd')
new   1: insert into customers (customer_name) values ('Marks  Ltd')

1 row created.

SQL> select customer_name from customers;

CUSTOMER_NAME
------------------------------
Marks  Ltd

If you know your script includes (or may include) data containing '&' characters, and you do not want the substitution behaviour as above, then use set define off to switch off the behaviour while running the script:

SQL> set define off
SQL> insert into customers (customer_name) values ('Marks & Spencers Ltd');

1 row created.

SQL> select customer_name from customers;

CUSTOMER_NAME
------------------------------
Marks & Spencers Ltd

You might want to add set define on at the end of the script to restore the default behaviour.

IllegalArgumentException or NullPointerException for a null parameter?

If it's a setter method and null is being passed to it, I think it would make more sense to throw an IllegalArgumentException. A NullPointerException seems to make more sense in the case where you're attempting to actually use the null.

So, if you're using it and it's null, NullPointer. If it's being passed in and it's null, IllegalArgument.

Html.BeginForm and adding properties

As part of htmlAttributes,e.g.

Html.BeginForm(
    action, controller, FormMethod.Post, new { enctype="multipart/form-data"})

Or you can pass null for action and controller to get the same default target as for BeginForm() without any parameters:

Html.BeginForm(
    null, null, FormMethod.Post, new { enctype="multipart/form-data"})

How to get 2 digit year w/ Javascript?

 
var d = new Date();
var n = d.getFullYear();

Yes, n will give you the 4 digit year, but you can always use substring or something similar to split up the year, thus giving you only two digits:

var final = n.toString().substring(2);

This will give you the last two digits of the year (2013 will become 13, etc...)

If there's a better way, hopefully someone posts it! This is the only way I can think of. Let us know if it works!

How do I disable form fields using CSS?

You can't use CSS to disable Textbox. solution would be HTML Attribute.

disabled="disabled"

Convert dd-mm-yyyy string to date

The accepted answer kinda has a bug

var from = $("#datepicker").val().split("-")
var f = new Date(from[2], from[1] - 1, from[0])

Consider if the datepicker contains "77-78-7980" which is obviously not a valid date. This would result in:

var f = new Date(7980, 77, 77);
=> Date 7986-08-15T22:00:00.000Z

Which is probably not the desired result.

The reason for this is explained on the MDN site:

Where Date is called as a constructor with more than one argument, if values are greater than their logical range (e.g. 13 is provided as the month value or 70 for the minute value), the adjacent value will be adjusted. E.g. new Date(2013, 13, 1) is equivalent to new Date(2014, 1, 1).

A better way to solve the problem is:

const stringToDate = function(dateString) {
  const [dd, mm, yyyy] = dateString.split("-");
  return new Date(`${yyyy}-${mm}-${dd}`);
};

console.log(stringToDate('04-04-2019'));
// Date 2019-04-04T00:00:00.000Z

console.log(stringToDate('77-78-7980'));
// Invalid Date

This gives you the possibility to handle invalid input.

For example:

const date = stringToDate("77-78-7980");

if (date === "Invalid Date" || isNaN(date)) {
  console.log("It's all gone bad");
} else {
  // Do something with your valid date here
}

How to copy an object in Objective-C

I don't know the difference between that code and mine, but I have problems with that solution, so I read a little bit more and found that we have to set the object before return it. I mean something like:

#import <Foundation/Foundation.h>

@interface YourObject : NSObject <NSCopying>

@property (strong, nonatomic) NSString *name;
@property (strong, nonatomic) NSString *line;
@property (strong, nonatomic) NSMutableString *tags;
@property (strong, nonatomic) NSString *htmlSource;
@property (strong, nonatomic) NSMutableString *obj;

-(id) copyWithZone: (NSZone *) zone;

@end


@implementation YourObject


-(id) copyWithZone: (NSZone *) zone
{
    YourObject *copy = [[YourObject allocWithZone: zone] init];

    [copy setNombre: self.name];
    [copy setLinea: self.line];
    [copy setTags: self.tags];
    [copy setHtmlSource: self.htmlSource];

    return copy;
}

I added this answer because I have a lot of problems with this issue and I have no clue about why is it happening. I don't know the difference, but it's working for me and maybe it can be useful for others too : )

"Missing return statement" within if / for / while

That is illegal syntax. It is not an optional thing for you to return a variable. You MUST return a variable of the type you specify in your method.

public String myMethod()
{
    if(condition)
    {
       return x;
    }
}

You are effectively saying, I promise any class can use this method(public) and I promise it will always return a String(String).

Then you are saying IF my condition is true I will return x. Well that is too bad, there is no IF in your promise. You promised that myMethod will ALWAYS return a String. Even if your condition is ALWAYS true the compiler has to assume that there is a possibility of it being false. Therefore you always need to put a return at the end of your non-void method outside of any conditions JUST IN CASE all of your conditions fail.

public String myMethod()
{
    if(condition)
    {
       return x;
    }
  return ""; //or whatever the default behavior will be if all of your conditions fail to return.
}

Set element focus in angular way

The problem with your solution is that it does not work well when tied down to other directives that creates a new scope, e.g. ng-repeat. A better solution would be to simply create a service function that enables you to focus elements imperatively within your controllers or to focus elements declaratively in the html.

DEMO

JAVASCRIPT

Service

 .factory('focus', function($timeout, $window) {
    return function(id) {
      // timeout makes sure that it is invoked after any other event has been triggered.
      // e.g. click events that need to run before the focus or
      // inputs elements that are in a disabled state but are enabled when those events
      // are triggered.
      $timeout(function() {
        var element = $window.document.getElementById(id);
        if(element)
          element.focus();
      });
    };
  });

Directive

  .directive('eventFocus', function(focus) {
    return function(scope, elem, attr) {
      elem.on(attr.eventFocus, function() {
        focus(attr.eventFocusId);
      });

      // Removes bound events in the element itself
      // when the scope is destroyed
      scope.$on('$destroy', function() {
        elem.off(attr.eventFocus);
      });
    };
  });

Controller

.controller('Ctrl', function($scope, focus) {
    $scope.doSomething = function() {
      // do something awesome
      focus('email');
    };
  });

HTML

<input type="email" id="email" class="form-control">
<button event-focus="click" event-focus-id="email">Declarative Focus</button>
<button ng-click="doSomething()">Imperative Focus</button>

How to tell CRAN to install package dependencies automatically?

Another possibility is to select the Install Dependencies checkbox In the R package installer, on the bottom right:

enter image description here

What are the differences between Deferred, Promise and Future in JavaScript?

In light of apparent dislike for how I've attempted to answer the OP's question. The literal answer is, a promise is something shared w/ other objects, while a deferred should be kept private. Primarily, a deferred (which generally extends Promise) can resolve itself, while a promise might not be able to do so.

If you're interested in the minutiae, then examine Promises/A+.

So far as I'm aware, the overarching purpose is to improve clarity and loosen coupling through a standardized interface. See suggested reading from @jfriend00:

Rather than directly passing callbacks to functions, something which can lead to tightly coupled interfaces, using promises allows one to separate concerns for code that is synchronous or asynchronous.

Personally, I've found deferred especially useful when dealing with e.g. templates that are populated by asynchronous requests, loading scripts that have networks of dependencies, and providing user feedback to form data in a non-blocking manner.

Indeed, compare the pure callback form of doing something after loading CodeMirror in JS mode asynchronously (apologies, I've not used jQuery in a while): 

/* assume getScript has signature like: function (path, callback, context) 
   and listens to onload && onreadystatechange */
$(function () {
   getScript('path/to/CodeMirror', getJSMode);

   // onreadystate is not reliable for callback args.
   function getJSMode() {
       getScript('path/to/CodeMirror/mode/javascript/javascript.js', 
           ourAwesomeScript);
   };

   function ourAwesomeScript() {
       console.log("CodeMirror is awesome, but I'm too impatient.");
   };
});

To the promises formulated version (again, apologies, I'm not up to date on jQuery):

/* Assume getScript returns a promise object */
$(function () {
   $.when(
       getScript('path/to/CodeMirror'),
       getScript('path/to/CodeMirror/mode/javascript/javascript.js')
   ).then(function () {
       console.log("CodeMirror is awesome, but I'm too impatient.");
   });
});

Apologies for the semi-pseudo code, but I hope it makes the core idea somewhat clear. Basically, by returning a standardized promise, you can pass the promise around, thus allowing for more clear grouping.

css transform, jagged edges in chrome

Adding a 1px transparent border will trigger anti-aliasing

outline: 1px solid transparent;

Alternatively, add a 1px transparent box-shadow.

box-shadow: 0 0 1px rgba(255,255,255,0);

How to declare an array inside MS SQL Server Stored Procedure?

T-SQL doesn't support arrays that I'm aware of.

What's your table structure? You could probably design a query that does this instead:

select
month,
sum(sales)
from sales_table
group by month
order by month

Is there anyway to exclude artifacts inherited from a parent POM?

Redefine the dependency (in the child pom) with scope system pointing to an empty jar :

<dependency>
    <groupId>dependency.coming</groupId>
    <artifactId>from.parent</artifactId>
    <version>0</version>
    <scope>system</scope>
    <systemPath>${project.basedir}/empty.jar</systemPath>
</dependency>

The jar can contain just a single empty file :

touch empty.txt
jar cvf empty.txt

Generating random integer from a range

In this thread rejection sampling was already discussed, but I wanted to suggest one optimization based on the fact that rand() % 2^something does not introduce any bias as already mentioned above.

The algorithm is really simple:

  • calculate the smallest power of 2 greater than the interval length
  • randomize one number in that "new" interval
  • return that number if it is less than the length of the original interval
    • reject otherwise

Here's my sample code:

int randInInterval(int min, int max) {
    int intervalLen = max - min + 1;
    //now calculate the smallest power of 2 that is >= than `intervalLen`
    int ceilingPowerOf2 = pow(2, ceil(log2(intervalLen)));

    int randomNumber = rand() % ceilingPowerOf2; //this is "as uniform as rand()"

    if (randomNumber < intervalLen)
        return min + randomNumber;      //ok!
    return randInInterval(min, max);    //reject sample and try again
}

This works well especially for small intervals, because the power of 2 will be "nearer" to the real interval length, and so the number of misses will be smaller.

PS
Obviously avoiding the recursion would be more efficient (no need to calculate over and over the log ceiling..) but I thought it was more readable for this example.

Create local maven repository

If maven is not creating Local Repository i.e .m2/repository folder then try below step.

In your Eclipse\Spring Tool Suite, Go to Window->preferences-> maven->user settings-> click on Restore Defaults-> Apply->Apply and close

How to update Identity Column in SQL Server?

You can not update identity column.

SQL Server does not allow to update the identity column unlike what you can do with other columns with an update statement.

Although there are some alternatives to achieve a similar kind of requirement.

  • When Identity column value needs to be updated for new records

Use DBCC CHECKIDENT which checks the current identity value for the table and if it's needed, changes the identity value.

DBCC CHECKIDENT('tableName', RESEED, NEW_RESEED_VALUE)
  • When Identity column value needs to be updated for existing records

Use IDENTITY_INSERT which allows explicit values to be inserted into the identity column of a table.

SET IDENTITY_INSERT YourTable {ON|OFF}

Example:

-- Set Identity insert on so that value can be inserted into this column
SET IDENTITY_INSERT YourTable ON
GO
-- Insert the record which you want to update with new value in the identity column
INSERT INTO YourTable(IdentityCol, otherCol) VALUES(13,'myValue')
GO
-- Delete the old row of which you have inserted a copy (above) (make sure about FK's)
DELETE FROM YourTable WHERE ID=3
GO
--Now set the idenetity_insert OFF to back to the previous track
SET IDENTITY_INSERT YourTable OFF

Axios get access to response header fields

According to official docs:

This may help if you want the HTTP headers that the server responded with. All header names are lower cased and can be accessed using the bracket notation. Example: response.headers['content-type'] will give something like: headers: {},

How to represent empty char in Java Character class

 
char ch = Character.MIN_VALUE;

The code above will initialize the variable ch with the minimum value that a char can have (i.e. \u0000).

Warning: Failed propType: Invalid prop `component` supplied to `Route`

This is definitely a syntax issue, when it happened to me I discovered I typed

module.export = Component; instead of module.exports = Component;

Trim spaces from end of a NSString

A simple solution to only trim one end instead of both ends in Objective-C:

@implementation NSString (category)

/// trims the characters at the end
- (NSString *)stringByTrimmingSuffixCharactersInSet:(NSCharacterSet *)characterSet {
    NSUInteger i = self.length;
    while (i > 0 && [characterSet characterIsMember:[self characterAtIndex:i - 1]]) {
        i--;
    }
    return [self substringToIndex:i];
}

@end

And a symmetrical utility for trimming the beginning only:

@implementation NSString (category)

/// trims the characters at the beginning
- (NSString *)stringByTrimmingPrefixCharactersInSet:(NSCharacterSet *)characterSet {
    NSUInteger i = 0;
    while (i < self.length && [characterSet characterIsMember:[self characterAtIndex:i]]) {
        i++;
    }
    return [self substringFromIndex:i];
}

@end

Twitter Bootstrap and ASP.NET GridView

There are 2 steps to resolve this:

  1. Add UseAccessibleHeader="true" to Gridview tag:

    <asp:GridView ID="MyGridView" runat="server" UseAccessibleHeader="true">

  2. Add the following Code to the PreRender event:


Protected Sub MyGridView_PreRender(sender As Object, e As EventArgs) Handles MyGridView.PreRender
    Try
        MyGridView.HeaderRow.TableSection = TableRowSection.TableHeader
    Catch ex As Exception
    End Try
End Sub

Note setting Header Row in DataBound() works only when the object is databound, any other postback that doesn't databind the gridview will result in the gridview header row style reverting to a standard row again. PreRender works everytime, just make sure you have an error catch for when the gridview is empty.

How To have Dynamic SQL in MySQL Stored Procedure

I don't believe MySQL supports dynamic sql. You can do "prepared" statements which is similar, but different.

Here is an example:

mysql> PREPARE stmt FROM 
    -> 'select count(*) 
    -> from information_schema.schemata 
    -> where schema_name = ? or schema_name = ?'
;
Query OK, 0 rows affected (0.00 sec)
Statement prepared
mysql> EXECUTE stmt 
    -> USING @schema1,@schema2
+----------+
| count(*) |
+----------+
|        2 |
+----------+
1 row in set (0.00 sec)
mysql> DEALLOCATE PREPARE stmt;

The prepared statements are often used to see an execution plan for a given query. Since they are executed with the execute command and the sql can be assigned to a variable you can approximate the some of the same behavior as dynamic sql.

Here is a good link about this:

Don't forget to deallocate the stmt using the last line!

Good Luck!

Getting Checkbox Value in ASP.NET MVC 4

Since you are using Model.Name to set the value. I assume you are passing an empty view model to the View.

So the value for Remember is false, and sets the value on the checkbox element to false. This means that when you then select the checkbox, you are posting the value "false" with the form. When you don't select it, it doesn't get posted, so the model defaults to false. Which is why you are seeing a false value in both cases.

The value is only passed when you check the select box. To do a checkbox in Mvc use

@Html.CheckBoxFor(x => x.Remember)

or if you don't want to bind the model to the view.

@Html.CheckBox("Remember")

Mvc does some magic with a hidden field to persist values when they are not selected.

Edit, if you really have an aversion to doing that and want to generate the element yourself, you could do.

<input id="Remember" name="Remember" type="checkbox" value="true" @(Model.Remember ? "checked=\"checked\"" : "") />

Carousel with Thumbnails in Bootstrap 3.0

Bootstrap 4 (update 2019)

A multi-item carousel can be accomplished in several ways as explained here. Another option is to use separate thumbnails to navigate the carousel slides.

Bootstrap 3 (original answer)

This can be done using the grid inside each carousel item.

       <div id="myCarousel" class="carousel slide">
                <div class="carousel-inner">
                    <div class="item active">
                        <div class="row">
                            <div class="col-sm-3">..
                            </div>
                            <div class="col-sm-3">..
                            </div>
                            <div class="col-sm-3">..
                            </div>
                            <div class="col-sm-3">..
                            </div>
                        </div>
                        <!--/row-->
                    </div>
                    ...add more item(s)
                 </div>
        </div>

Demo example thumbnail slider using the carousel:
http://www.bootply.com/81478

Another example with carousel indicators as thumbnails: http://www.bootply.com/79859

AccessDenied for ListObjects for S3 bucket when permissions are s3:*

I got the same error when using policy as below, although i have "s3:ListBucket" for s3:ListObjects operation.

{
"Version": "2012-10-17",
"Statement": [
    {
        "Action": [
            "s3:ListBucket",
            "s3:GetObject",
            "s3:GetObjectAcl"
        ],
        "Resource": [
            "arn:aws:s3:::<bucketname>/*",
            "arn:aws:s3:::*-bucket/*"
        ],
        "Effect": "Allow"
    }
  ]
 }

Then i fixed it by adding one line "arn:aws:s3:::bucketname" 

{
"Version": "2012-10-17",
"Statement": [
    {
        "Action": [
            "s3:ListBucket",
            "s3:GetObject",
            "s3:GetObjectAcl"
        ],
        "Resource": [
             "arn:aws:s3:::<bucketname>",
            "arn:aws:s3:::<bucketname>/*",
            "arn:aws:s3:::*-bucket/*"
        ],
        "Effect": "Allow"
    }
 ]
}

Call a method of a controller from another controller using 'scope' in AngularJS

Here is good Demo in Fiddle how to use shared service in directive and other controllers through $scope.$on

HTML

<div ng-controller="ControllerZero">
    <input ng-model="message" >
    <button ng-click="handleClick(message);">BROADCAST</button>
</div>

<div ng-controller="ControllerOne">
    <input ng-model="message" >
</div>

<div ng-controller="ControllerTwo">
    <input ng-model="message" >
</div>

<my-component ng-model="message"></my-component>

JS

var myModule = angular.module('myModule', []);

myModule.factory('mySharedService', function($rootScope) {
    var sharedService = {};

    sharedService.message = '';

    sharedService.prepForBroadcast = function(msg) {
        this.message = msg;
        this.broadcastItem();
    };

    sharedService.broadcastItem = function() {
        $rootScope.$broadcast('handleBroadcast');
    };

    return sharedService;
});

By the same way we can use shared service in directive. We can implement controller section into directive and use $scope.$on

myModule.directive('myComponent', function(mySharedService) {
    return {
        restrict: 'E',
        controller: function($scope, $attrs, mySharedService) {
            $scope.$on('handleBroadcast', function() {
                $scope.message = 'Directive: ' + mySharedService.message;
            });
        },
        replace: true,
        template: '<input>'
    };
});

And here three our controllers where ControllerZero used as trigger to invoke prepForBroadcast

function ControllerZero($scope, sharedService) {
    $scope.handleClick = function(msg) {
        sharedService.prepForBroadcast(msg);
    };

    $scope.$on('handleBroadcast', function() {
        $scope.message = sharedService.message;
    });
}

function ControllerOne($scope, sharedService) {
    $scope.$on('handleBroadcast', function() {
        $scope.message = 'ONE: ' + sharedService.message;
    });
}

function ControllerTwo($scope, sharedService) {
    $scope.$on('handleBroadcast', function() {
        $scope.message = 'TWO: ' + sharedService.message;
    });
}

The ControllerOne and ControllerTwo listen message change by using $scope.$on handler.

The filename, directory name, or volume label syntax is incorrect inside batch

 
set myPATH="C:\Users\DEB\Downloads\10.1.1.0.4"
cd %myPATH%

  • The single quotes do not indicate a string, they make it starts: 'C:\ instead of C:\ so

  • %name% is the usual syntax for expanding a variable, the !name! syntax needs to be enabled using the command setlocal ENABLEDELAYEDEXPANSION first, or by running the command prompt with CMD /V:ON.

  • Don't use PATH as your name, it is a system name that contains all the locations of executable programs. If you overwrite it, random bits of your script will stop working. If you intend to change it, you need to do set PATH=%PATH%;C:\Users\DEB\Downloads\10.1.1.0.4 to keep the current PATH content, and add something to the end.

Spacing between elements

If you want vertical spacing between elements, use a margin.

Don't add extra elements if you don't need to.

How to generate a simple popup using jQuery

ONLY CSS POPUP LOGIC! TRY DO IT . EASY! I think this mybe be hack popular in future

            <a href="#openModal">OPEN</a>

            <div id="openModal" class="modalDialog">
                <div>
                    <a href="#close"  class="close">X</a>
                    <h2>MODAL</h2>

                </div>
            </div>


.modalDialog {
    position: fixed;
    font-family: Arial, Helvetica, sans-serif;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    background: rgba(0,0,0,0.8);
    z-index: 99999;
    -webkit-transition: opacity 400ms ease-in;
    -moz-transition: opacity 400ms ease-in;
    transition: opacity 400ms ease-in;
    display: none;
    pointer-events: none;
}

.modalDialog:target {
    display: block;
    pointer-events: auto;
}

.modalDialog > div {
    width: 400px;
    position: relative;
    margin: 10% auto;
    padding: 5px 20px 13px 20px;
    border-radius: 10px;
    background: #fff;
    background: -moz-linear-gradient(#fff, #999);
    background: -webkit-linear-gradient(#fff, #999);
    background: -o-linear-gradient(#fff, #999);
}

DOS: find a string, if found then run another script

We have two commands, first is "condition_command", second is "result_command". If we need run "result_command" when "condition_command" is successful (errorlevel=0):

condition_command && result_command

If we need run "result_command" when "condition_command" is fail:

condition_command || result_command

Therefore for run "some_command" in case when we have "string" in the file "status.txt":

find "string" status.txt 1>nul && some_command

in case when we have not "string" in the file "status.txt":

find "string" status.txt 1>nul || some_command

Difference between xcopy and robocopy

I have written lot of scripts to automate daily backups etc. Previously I used XCopy and then moved to Robocopy. Anyways Robocopy and XCopy both are frequently used in terms of file transfers in Windows. Robocopy stands for Robust File Copy. All type of huge file copying both these commands are used but Robocopy has added options which makes copying easier as well as for debugging purposes.

Having said that lets talk about features between these two.

  • Robocopy becomes handy for mirroring or synchronizing directories. It also checks the files in the destination directory against the files to be copied and doesn't waste time copying unchanged files.

  • Just like myself, if you are into automation to take daily backups etc, "Run Hours - /RH" becomes very useful without any interactions. This is supported by Robocopy. It allows you to set when copies should be done rather than the time of the command as with XCopy. You will see robocopy.exe process in task list since it will run background to monitor clock to execute when time is right to copy.

  • Robocopy supports file and directory monitoring with the "/MON" or "/MOT" commands.

  • Robocopy gives extra support for copying over the "archive" attribute on files, it supports copying over all attributes including timestamps, security, owner, and auditing information.

Hope this helps you.

using setTimeout on promise chain

 
.then(() => new Promise((resolve) => setTimeout(resolve, 15000)))

UPDATE:

when I need sleep in async function I throw in

await new Promise(resolve => setTimeout(resolve, 1000))

How do you reindex an array in PHP but with indexes starting from 1?

Duplicate removal and reindex an array:

<?php  
   $oldArray = array('0'=>'php','1'=>'java','2'=>'','3'=>'asp','4'=>'','5'=>'mysql');
   //duplicate removal
   $fillteredArray = array_filter($oldArray);
   //reindexing actually happens  here
   $newArray = array_merge($filteredArray);
   print_r($newArray);
?>

How to redirect stderr and stdout to different files in the same line in script?

Try this:

your_command 2>stderr.log 1>stdout.log

More information

The numerals 0 through 9 are file descriptors in bash. 0 stands for standard input, 1 stands for standard output, 2 stands for standard error. 3 through 9 are spare for any other temporary usage.

Any file descriptor can be redirected to a file or to another file descriptor using the operator >. You can instead use the operator >> to appends to a file instead of creating an empty one.

Usage:

file_descriptor > filename

file_descriptor > &file_descriptor

Please refer to Advanced Bash-Scripting Guide: Chapter 20. I/O Redirection.

How good is Java's UUID.randomUUID?

I'm not an expert, but I'd assume that enough smart people looked at Java's random number generator over the years. Hence, I'd also assume that random UUIDs are good. So you should really have the theoretical collision probability (which is about 1 : 3 × 10^38 for all possible UUIDs. Does anybody know how this changes for random UUIDs only? Is it 1/(16*4) of the above?)

From my practical experience, I've never seen any collisions so far. I'll probably have grown an astonishingly long beard the day I get my first one ;)

What is the difference between "is None" and "== None"

The answer is explained here.

To quote:

A class is free to implement comparison any way it chooses, and it can choose to make comparison against None mean something (which actually makes sense; if someone told you to implement the None object from scratch, how else would you get it to compare True against itself?).

Practically-speaking, there is not much difference since custom comparison operators are rare. But you should use is None as a general rule.

Join/Where with LINQ and Lambda

Daniel has a good explanation of the syntax relationships, but I put this document together for my team in order to make it a little simpler for them to understand. Hope this helps someoneenter image description here

Disable submit button on form submit

Want to submit value of button as well and prevent double form submit?

If you are using button of type submit and want to submit value of button as well, which will not happen if the button is disabled, you can set a form data attribute and test afterwards.

// Add class disableonsubmit to your form
    $(document).ready(function () {
        $('form.disableonsubmit').submit(function(e) {
            if ($(this).data('submitted') === true) {
                // Form is already submitted
                console.log('Form is already submitted, waiting response.');
                // Stop form from submitting again
                e.preventDefault();
            } else {
                // Set the data-submitted attribute to true for record
                $(this).data('submitted', true);
            }
        });
    });

How to draw a rounded Rectangle on HTML Canvas?

try to add this line , when you want to get rounded corners : ctx.lineCap = "round";

WCF timeout exception detailed investigation

I've just solved the problem.I found that the nodes in the App.config file have configed wrong.

<client>
<endpoint name="WCF_QtrwiseSalesService" binding="wsHttpBinding" bindingConfiguration="ws" address="http://cntgbs1131:9005/MyService/TGE.ISupplierClientManager" contract="*">
</endpoint>
</client>

<bindings>
    <wsHttpBinding>
        <binding name="ws" maxBufferPoolSize="2147483647" maxReceivedMessageSize="2147483647" messageEncoding="Text">
            <readerQuotas maxDepth="2147483647" maxStringContentLength="2147483647" maxArrayLength="2147483647" maxBytesPerRead="2147483647" maxNameTableCharCount="2147483647"/>
            <**security mode="None">**
                <transport clientCredentialType="None"></transport>
            </security>
        </binding>
    </wsHttpBinding>
</bindings>

Confirm your config in the node <security>,the attribute "mode" value is "None". If your value is "Transport",the error occurs.

How to get the current TimeStamp?

In Qt 4.7, there is the QDateTime::currentMSecsSinceEpoch() static function, which does exactly what you need, without any intermediary steps. Hence I'd recommend that for projects using Qt 4.7 or newer.

How to convert Strings to and from UTF8 byte arrays in Java

If you are using 7-bit ASCII or ISO-8859-1 (an amazingly common format) then you don't have to create a new java.lang.String at all. It's much much more performant to simply cast the byte into char:

Full working example:

for (byte b : new byte[] { 43, 45, (byte) 215, (byte) 247 }) {
    char c = (char) b;
    System.out.print(c);
}

If you are not using extended-characters like Ä, Æ, Å, Ç, Ï, Ê and can be sure that the only transmitted values are of the first 128 Unicode characters, then this code will also work for UTF-8 and extended ASCII (like cp-1252).

How to perform a sum of an int[] array

Your syntax and logic are incorrect in a number of ways. You need to create an index variable and use it to access the array's elements, like so:

int i = 0;        // Create a separate integer to serve as your array indexer.
while(i < 10) {   // The indexer needs to be less than 10, not A itself.
   sum += A[i];   // either sum = sum + ... or sum += ..., but not both
   i++;           // You need to increment the index at the end of the loop.
}

The above example uses a while loop, since that's the approach you took. A more appropriate construct would be a for loop, as in Bogdan's answer.

"The page you are requesting cannot be served because of the extension configuration." error message

In my case I needed to add MIME types for each file extension that I wanted to serve to web config:

<system.webServer>
    <staticContent>
      <mimeMap fileExtension=".shp" mimeType="application/octet-stream" />
      <mimeMap fileExtension=".dbf" mimeType="application/octet-stream" />
      <mimeMap fileExtension=".kml" mimeType="text/xml" />
    </staticContent>
    ...
</system.webServer>

"Multiple definition", "first defined here" errors

You should not include commands.c in your header file. In general, you should not include .c files. Rather, commands.c should include commands.h. As defined here, the C preprocessor is inserting the contents of commands.c into commands.h where the include is. You end up with two definitions of f123 in commands.h.

commands.h

#ifndef COMMANDS_H_
#define COMMANDS_H_

void f123();

#endif

commands.c

#include "commands.h"

void f123()
{
    /* code */
}

How to a convert a date to a number and back again in MATLAB

Use DATESTR

>> datestr(40189)
ans =
12-Jan-0110

Unfortunately, Excel starts counting at 1-Jan-1900. Find out how to convert serial dates from Matlab to Excel by using DATENUM

>> datenum(2010,1,11)
ans =
      734149
>> datenum(2010,1,11)-40189
ans =
      693960
>> datestr(40189+693960)
ans =
11-Jan-2010

In other words, to convert any serial Excel date, call

datestr(excelSerialDate + 693960)

EDIT

To get the date in mm/dd/yyyy format, call datestr with the specified format

excelSerialDate = 40189;
datestr(excelSerialDate + 693960,'mm/dd/yyyy')
ans =
01/11/2010

Also, if you want to get rid of the leading zero for the month, you can use REGEXPREP to fix things

excelSerialDate = 40189;
regexprep(datestr(excelSerialDate + 693960,'mm/dd/yyyy'),'^0','')
ans =
1/11/2010

Where is `%p` useful with printf?

The size of the pointer may be something different than that of int. Also an implementation could produce better than simple hex value representation of the address when you use %p.

Passing parameters to JavaScript files

might be very simple

for example 

<script src="js/myscript.js?id=123"></script>
<script>
    var queryString = $("script[src*='js/myscript.js']").attr('src').split('?')[1];
</script>

You can then convert query string into json like below

var json = $.parseJSON('{"' 
            + queryString.replace(/&/g, '","').replace(/=/g, '":"') 
            + '"}');

and then can use like 

console.log(json.id);

Express.js: how to get remote client address

Putting all together witk @kakopappa solution plus morgan logging of the client ip address:

morgan.token('client_ip', function getId(req) {
    return req.client_ip
});
const LOG_OUT = ':remote-addr - :remote-user [:date[clf]] ":method :url HTTP/:http-version" :status :res[content-length] ":referrer" ":user-agent" :client_ip'
self.app.use(morgan(LOG_OUT, {
    skip: function(req, res) { // custom logging: filter status codes
        return res.statusCode < self._options.logging.statusCode;
    }
}));

// could-flare, nginx and x-real-ip support
var getIpInfoMiddleware = function(req, res, next) {
    var client_ip;
    if (req.headers['cf-connecting-ip'] && req.headers['cf-connecting-ip'].split(', ').length) {
        var first = req.headers['cf-connecting-ip'].split(', ');
        client_ip = first[0];
    } else {
        client_ip = req.headers['x-forwarded-for'] || req.headers['x-real-ip'] || req.connection.remoteAddress || req.socket.remoteAddress || req.connection.socket.remoteAddress;
    }
    req.client_ip = client_ip;
    next();
};
self.app.use(getIpInfoMiddleware);

ORA-00979 not a group by expression

Include in the GROUP BY clause all SELECT expressions that are not group function arguments.

Creating temporary files in bash

You might want to look at mktemp

The mktemp utility takes the given filename template and overwrites a portion of it to create a unique filename. The template may be any filename with some number of 'Xs' appended to it, for example /tmp/tfile.XXXXXXXXXX. The trailing 'Xs' are replaced with a combination of the current process number and random letters.

For more details: man mktemp

How do I alter the precision of a decimal column in Sql Server?

Go to enterprise manager, design table, click on your field.

Make a decimal column

In the properties at the bottom there is a precision property

Any way to declare an array in-line?

You can create a method somewhere

public static <T> T[] toArray(T... ts) {
    return ts;
}

then use it

m(toArray("blah", "hey", "yo"));

for better look.

laravel Eloquent ORM delete() method

 
$model=User::where('id',$id)->delete();

HttpClient - A task was cancelled?

in my .net core 3.1 applications I am getting two problem where inner cause was timeout exception. 1, one is i am getting aggregate exception and in it's inner exception was timeout exception 2, other case was Task canceled exception

My solution is

catch (Exception ex)
            {
                if (ex.InnerException is TimeoutException)
                {
                    ex = ex.InnerException;
                }
                else if (ex is TaskCanceledException)
                {
                    if ((ex as TaskCanceledException).CancellationToken == null || (ex as TaskCanceledException).CancellationToken.IsCancellationRequested == false)
                    {
                        ex = new TimeoutException("Timeout occurred");
                    }
                }                
                Logger.Fatal(string.Format("Exception at calling {0} :{1}", url, ex.Message), ex);
            }

What is the default value for enum variable?

It is whatever member of the enumeration represents the value 0. Specifically, from the documentation:

The default value of an enum E is the value produced by the expression (E)0.

As an example, take the following enum:

enum E
{
    Foo, Bar, Baz, Quux
}

Without overriding the default values, printing default(E) returns Foo since it's the first-occurring element.

However, it is not always the case that 0 of an enum is represented by the first member. For example, if you do this:

enum F
{
    // Give each element a custom value
    Foo = 1, Bar = 2, Baz = 3, Quux = 0
}

Printing default(F) will give you Quux, not Foo.

If none of the elements in an enum G correspond to 0:

enum G
{
    Foo = 1, Bar = 2, Baz = 3, Quux = 4
}

default(G) returns literally 0, although its type remains as G (as quoted by the docs above, a cast to the given enum type).

PHP Session Destroy on Log Out Button

First give the link of logout.php page in that logout button.In that page make the code which is given below:

Here is the code:

<?php
 session_start();
 session_destroy();
?>

When the session has started, the session for the last/current user has been started, so don't need to declare the username. It will be deleted automatically by the session_destroy method.

How to style input and submit button with CSS?

When styling a input type submit use the following code.

   input[type=submit] {
    background-color: pink; //Example stlying
    }

ImageView - have height match width?

To set your ImageView equal to half the screen, you need to add the following to your XML for the ImageView:

<ImageView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_centerInParent="true"
    android:scaleType="fitXY"
    android:adjustViewBounds="true"/>

To then set the height equal to this width, you need to do it in code. In the getView method of your GridView adapter, set the ImageView height equal to its measured width:

mImageView.getLayoutParams().height = mImageView.getMeasuredWidth();

How do I write a compareTo method which compares objects?

if (s.compareTo(t) > 0) will compare string s to string t and return the int value you want.

    public int Compare(Object obj) // creating a method to compare {   
        Student s = (Student) obj; //creating a student object

        // compare last names
        return  this.lastName.compareTo(s.getLastName());    
    }

Now just test for a positive negative return from the method as you would have normally.

Cheers

MySQL select rows where left join is null

One of the best approach if you do not want to return any columns from table2 is to use the NOT EXISTS

SELECT  table1.id 
FROM    table1 T1
WHERE
  NOT EXISTS (SELECT *
              FROM table2 T2
              WHERE T1.id = T2.user_one
                  OR T1.id = T2.user_two)

Semantically this says what you want to query: Select every row where there is no matching record in the second table.

MySQL is optimized for EXISTS: It returns as soon as it finds the first matching record.

How to Convert double to int in C?

This is the notorious floating point rounding issue. Just add a very small number, to correct the issue.

double a;
a=3669.0;
int b;
b=a+ 1e-9;

Find integer index of rows with NaN in pandas dataframe

Here is another simpler take:

df = pd.DataFrame([[0,1,3,4,np.nan,2],[3,5,6,np.nan,3,3]])

inds = np.asarray(df.isnull()).nonzero()

(array([0, 1], dtype=int64), array([4, 3], dtype=int64))

Retrofit 2: Get JSON from Response body

add dependency for retrofit2 

compile 'com.google.code.gson:gson:2.6.2'
compile 'com.squareup.retrofit2:retrofit:2.0.2'
compile 'com.squareup.retrofit2:converter-gson:2.0.2'

create class for base url

public class ApiClient     
{
public static final String BASE_URL = "base_url";

private static Retrofit retrofit = null;

public static Retrofit getClient() {
    if (retrofit==null) {
        retrofit = new Retrofit.Builder()
                .baseUrl(BASE_URL)
                .addConverterFactory(GsonConverterFactory.create())
                .build();
    }
    return retrofit;
}

}

after that create class model to get value

public class ApprovalModel {

@SerializedName("key_parameter")
private String approvalName;
public String getApprovalName() {
    return approvalName;
}
}

create interface class

public interface ApiInterface { 
@GET("append_url")
Call<CompanyDetailsResponse> getCompanyDetails();
}

after that in main class

 if(Connectivity.isConnected(mContext)){
            final ProgressDialog mProgressDialog = new ProgressDialog(mContext);
            mProgressDialog.setIndeterminate(true);
            mProgressDialog.setMessage("Loading...");
            mProgressDialog.show();

            ApiInterface apiService =
                    ApiClient.getClient().create(ApiInterface.class);

            Call<CompanyDetailsResponse> call = apiService.getCompanyDetails();
            call.enqueue(new Callback<CompanyDetailsResponse>() {
                @Override
                public void onResponse(Call<CompanyDetailsResponse>call, Response<CompanyDetailsResponse> response) {
                    mProgressDialog.dismiss();
                    if(response!=null && response.isSuccessful()) {
                        List<CompanyDetails> companyList = response.body().getCompanyDetailsList();

                        if (companyList != null&&companyList.size()>0) {
                            for (int i = 0; i < companyList.size(); i++) {
                                Log.d(TAG, "" + companyList.get(i));
                            }
                         //get values
                        }else{
                            //show alert not get value
                        }
                    }else{
                        //show error message

                    }
                }

                @Override
                public void onFailure(Call<CompanyDetailsResponse>call, Throwable t) {
                    // Log error here since request failed
                    Log.e(TAG, t.toString());
                    mProgressDialog.dismiss();
                }
            });
        }else{
            //network error alert box

        }

Set mouse focus and move cursor to end of input using jQuery

Hope this help you:

var fieldInput = $('#fieldName');
var fldLength= fieldInput.val().length;
fieldInput.focus();
fieldInput[0].setSelectionRange(fldLength, fldLength);

Visual Studio setup problem - 'A problem has been encountered while loading the setup components. Canceling setup.'

A colleague found this MS auto-uninstall tool which has successfully uninstalled VS2008 for me and saved me hours of work!!

Hopefully this might be useful to others. Doesn't speak highly of MS's faith in their usual VS maintenance tools that they have to provide this as well!

swift 3.0 Data to String?

I came looking for the answer to the Swift 3 Data to String question and never got a good answer. After some fooling around I came up with this:

var testString = "This is a test string"
var somedata = testString.data(using: String.Encoding.utf8)
var backToString = String(data: somedata!, encoding: String.Encoding.utf8) as String!

'str' object has no attribute 'decode'. Python 3 error?

For Python3

html = """\\u003Cdiv id=\\u0022contenedor\\u0022\\u003E \\u003Ch2 class=\\u0022text-left m-b-2\\u0022\\u003EInformaci\\u00f3n del veh\\u00edculo de patente AA345AA\\u003C\\/h2\\u003E\\n\\n\\n\\n \\u003Cdiv class=\\u0022panel panel-default panel-disabled m-b-2\\u0022\\u003E\\n \\u003Cdiv class=\\u0022panel-body\\u0022\\u003E\\n \\u003Ch2 class=\\u0022table_title m-b-2\\u0022\\u003EInformaci\\u00f3n del Registro Automotor\\u003C\\/h2\\u003E\\n \\u003Cdiv class=\\u0022col-md-6\\u0022\\u003E\\n \\u003Clabel class=\\u0022control-label\\u0022\\u003ERegistro Seccional\\u003C\\/label\\u003E\\n \\u003Cp\\u003ESAN MIGUEL N\\u00b0 1\\u003C\\/p\\u003E\\n \\u003Clabel class=\\u0022control-label\\u0022\\u003EDirecci\\u00f3n\\u003C\\/label\\u003E\\n \\u003Cp\\u003EMAESTRO ANGEL D\\u0027ELIA 766\\u003C\\/p\\u003E\\n \\u003Clabel class=\\u0022control-label\\u0022\\u003EPiso\\u003C\\/label\\u003E\\n \\u003Cp\\u003EPB\\u003C\\/p\\u003E\\n \\u003Clabel class=\\u0022control-label\\u0022\\u003EDepartamento\\u003C\\/label\\u003E\\n \\u003Cp\\u003E-\\u003C\\/p\\u003E\\n \\u003Clabel class=\\u0022control-label\\u0022\\u003EC\\u00f3digo postal\\u003C\\/label\\u003E\\n \\u003Cp\\u003E1663\\u003C\\/p\\u003E\\n \\u003C\\/div\\u003E\\n \\u003Cdiv class=\\u0022col-md-6\\u0022\\u003E\\n \\u003Clabel class=\\u0022control-label\\u0022\\u003ELocalidad\\u003C\\/label\\u003E\\n \\u003Cp\\u003ESAN MIGUEL\\u003C\\/p\\u003E\\n \\u003Clabel class=\\u0022control-label\\u0022\\u003EProvincia\\u003C\\/label\\u003E\\n \\u003Cp\\u003EBUENOS AIRES\\u003C\\/p\\u003E\\n \\u003Clabel class=\\u0022control-label\\u0022\\u003ETel\\u00e9fono\\u003C\\/label\\u003E\\n \\u003Cp\\u003E(11)46646647\\u003C\\/p\\u003E\\n \\u003Clabel class=\\u0022control-label\\u0022\\u003EHorario\\u003C\\/label\\u003E\\n \\u003Cp\\u003E08:30 a 12:30\\u003C\\/p\\u003E\\n \\u003C\\/div\\u003E\\n \\u003C\\/div\\u003E\\n\\u003C\\/div\\u003E \\n\\n\\u003Cp class=\\u0022text-center m-t-3 m-b-1 hidden-print\\u0022\\u003E\\n \\u003Ca href=\\u0022javascript:window.print();\\u0022 class=\\u0022btn btn-default\\u0022\\u003EImprim\\u00ed la consulta\\u003C\\/a\\u003E \\u0026nbsp; \\u0026nbsp;\\n \\u003Ca href=\\u0022\\u0022 class=\\u0022btn use-ajax btn-primary\\u0022\\u003EHacer otra consulta\\u003C\\/a\\u003E\\n\\u003C\\/p\\u003E\\n\\u003C\\/div\\u003E"""

print(html.replace("\\/", "/").encode().decode('unicode_escape'))

UITableView example for Swift

In Swift 4.1 and Xcode 9.4.1

  1. Add UITableViewDataSource, UITableViewDelegate delegated to your class.

  2. Create table view variable and array.

  3. In viewDidLoad create table view.

  4. Call table view delegates

  5. Call table view delegate functions based on your requirement.

import UIKit
// 1
class yourViewController: UIViewController , UITableViewDataSource, UITableViewDelegate { 

// 2
var yourTableView:UITableView = UITableView()
let myArray = ["row 1", "row 2", "row 3", "row 4"]

override func viewDidLoad() {
    super.viewDidLoad()

    // 3
    yourTableView.frame = CGRect(x: 10, y: 10, width: view.frame.width-20, height: view.frame.height-200)
    self.view.addSubview(yourTableView)

    // 4
    yourTableView.dataSource = self
    yourTableView.delegate = self

}

// 5
// MARK - UITableView Delegates
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

    return myArray.count
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

var cell : UITableViewCell? = tableView.dequeueReusableCell(withIdentifier: "cell")
    if cell == nil {
        cell = UITableViewCell(style: UITableViewCellStyle.default, reuseIdentifier: "cell")
    }
    if self. myArray.count > 0 {
        cell?.textLabel!.text = self. myArray[indexPath.row]
    }
    cell?.textLabel?.numberOfLines = 0

    return cell!
}

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {

    return 50.0
}

If you are using storyboard, no need for Step 3.

But you need to create IBOutlet for your table view before Step 4.

How to check if a Java 8 Stream is empty?

This may be sufficient in many cases

stream.findAny().isPresent()

Android scale animation on view

Here is a code snip to do exactly that.

public void scaleView(View v, float startScale, float endScale) {
    Animation anim = new ScaleAnimation(
            1f, 1f, // Start and end values for the X axis scaling
            startScale, endScale, // Start and end values for the Y axis scaling
            Animation.RELATIVE_TO_SELF, 0f, // Pivot point of X scaling
            Animation.RELATIVE_TO_SELF, 1f); // Pivot point of Y scaling
    anim.setFillAfter(true); // Needed to keep the result of the animation
    anim.setDuration(1000);
    v.startAnimation(anim);
}

The ScaleAnimation constructor used here takes 8 args, 4 related to handling the X-scale which we don't care about (1f, 1f, ... Animation.RELATIVE_TO_SELF, 0f, ...).

The other 4 args are for the Y-scaling we do care about.

startScale, endScale - In your case, you'd use 0f, 0.6f.

Animation.RELATIVE_TO_SELF, 1f - This specifies where the shrinking of the view collapses to (referred to as the pivot in the documentation). Here, we set the float value to 1f because we want the animation to start growing the bar from the bottom. If we wanted it to grow downward from the top, we'd use 0f.

Finally, and equally important, is the call to anim.setFillAfter(true). If you want the result of the animation to stick around after the animation completes, you must run this on the animator before executing the animation.

So in your case, you can do something like this:

View v = findViewById(R.id.viewContainer);
scaleView(v, 0f, .6f);

How to find item with max value using linq?

With EF or LINQ to SQL:

var item = db.Items.OrderByDescending(i => i.Value).FirstOrDefault();

With LINQ to Objects I suggest to use morelinq extension MaxBy (get morelinq from nuget):

var item = items.MaxBy(i => i.Value);

How can bcrypt have built-in salts?

To make things even more clearer,

Registeration/Login direction ->

The password + salt is encrypted with a key generated from the: cost, salt and the password. we call that encrypted value the cipher text. then we attach the salt to this value and encoding it using base64. attaching the cost to it and this is the produced string from bcrypt:

$2a$COST$BASE64

This value is stored eventually.

What the attacker would need to do in order to find the password ? (other direction <- )

In case the attacker got control over the DB, the attacker will decode easily the base64 value, and then he will be able to see the salt. the salt is not secret. though it is random. Then he will need to decrypt the cipher text.

What is more important : There is no hashing in this process, rather CPU expensive encryption - decryption. thus rainbow tables are less relevant here.

How to change the Jupyter start-up folder

 
jupyter notebook --notebook-dir=%WORKING_DIR%,

where %WORKING_DIR% (H:\data\ML) - directory where you're going to work

It is the simplest one-line command way, IMHO

Detach (move) subdirectory into separate Git repository

Here is a small modification to CoolAJ86's "The Easy Way™" answer in order to split multiple sub folders (let's say sub1and sub2) into a new git repository.

The Easy Way™ (multiple sub folders)

  1. Prepare the old repo

    pushd <big-repo>
git filter-branch --tree-filter "mkdir <name-of-folder>; mv <sub1> <sub2> <name-of-folder>/" HEAD
git subtree split -P <name-of-folder> -b <name-of-new-branch>
popd

    Note: <name-of-folder> must NOT contain leading or trailing characters. For instance, the folder named subproject MUST be passed as subproject, NOT ./subproject/

    Note for windows users: when your folder depth is > 1, <name-of-folder> must have *nix style folder separator (/). For instance, the folder named path1\path2\subproject MUST be passed as path1/path2/subproject. Moreover don't use mvcommand but move.

    Final note: the unique and big difference with the base answer is the second line of the script "git filter-branch..."

  2. Create the new repo

    mkdir <new-repo>
pushd <new-repo>

git init
git pull </path/to/big-repo> <name-of-new-branch>

  3. Link the new repo to Github or wherever

    git remote add origin <[email protected]:my-user/new-repo.git>
git push origin -u master

  4. Cleanup, if desired

    popd # get out of <new-repo>
pushd <big-repo>

git rm -rf <name-of-folder>

    Note: This leaves all the historical references in the repository.See the Appendix in the original answer if you're actually concerned about having committed a password or you need to decreasing the file size of your .git folder.

Git - Pushing code to two remotes

In recent versions of Git you can add multiple pushurls for a given remote. Use the following to add two pushurls to your origin:

git remote set-url --add --push origin git://original/repo.git
git remote set-url --add --push origin git://another/repo.git

So when you push to origin, it will push to both repositories.

UPDATE 1: Git 1.8.0.1 and 1.8.1 (and possibly other versions) seem to have a bug that causes --add to replace the original URL the first time you use it, so you need to re-add the original URL using the same command. Doing git remote -v should reveal the current URLs for each remote.

UPDATE 2: Junio C. Hamano, the Git maintainer, explained it's how it was designed. Doing git remote set-url --add --push <remote_name> <url> adds a pushurl for a given remote, which overrides the default URL for pushes. However, you may add multiple pushurls for a given remote, which then allows you to push to multiple remotes using a single git push. You can verify this behavior below:

$ git clone git://original/repo.git
$ git remote -v
origin  git://original/repo.git (fetch)
origin  git://original/repo.git (push)
$ git config -l | grep '^remote\.'
remote.origin.url=git://original/repo.git
remote.origin.fetch=+refs/heads/*:refs/remotes/origin/*

Now, if you want to push to two or more repositories using a single command, you may create a new remote named all (as suggested by @Adam Nelson in comments), or keep using the origin, though the latter name is less descriptive for this purpose. If you still want to use origin, skip the following step, and use origin instead of all in all other steps.

So let's add a new remote called all that we'll reference later when pushing to multiple repositories:

$ git remote add all git://original/repo.git
$ git remote -v
all git://original/repo.git (fetch)               <-- ADDED
all git://original/repo.git (push)                <-- ADDED
origin  git://original/repo.git (fetch)
origin  git://original/repo.git (push)
$ git config -l | grep '^remote\.all'
remote.all.url=git://original/repo.git            <-- ADDED
remote.all.fetch=+refs/heads/*:refs/remotes/all/* <-- ADDED

Then let's add a pushurl to the all remote, pointing to another repository:

$ git remote set-url --add --push all git://another/repo.git
$ git remote -v
all git://original/repo.git (fetch)
all git://another/repo.git (push)                 <-- CHANGED
origin  git://original/repo.git (fetch)
origin  git://original/repo.git (push)
$ git config -l | grep '^remote\.all'
remote.all.url=git://original/repo.git
remote.all.fetch=+refs/heads/*:refs/remotes/all/*
remote.all.pushurl=git://another/repo.git         <-- ADDED

Here git remote -v shows the new pushurl for push, so if you do git push all master, it will push the master branch to git://another/repo.git only. This shows how pushurl overrides the default url (remote.all.url).

Now let's add another pushurl pointing to the original repository:

$ git remote set-url --add --push all git://original/repo.git
$ git remote -v
all git://original/repo.git (fetch)
all git://another/repo.git (push)
all git://original/repo.git (push)                <-- ADDED
origin  git://original/repo.git (fetch)
origin  git://original/repo.git (push)
$ git config -l | grep '^remote\.all'
remote.all.url=git://original/repo.git
remote.all.fetch=+refs/heads/*:refs/remotes/all/*
remote.all.pushurl=git://another/repo.git
remote.all.pushurl=git://original/repo.git        <-- ADDED

You see both pushurls we added are kept. Now a single git push all master will push the master branch to both git://another/repo.git and git://original/repo.git.

Adding System.Web.Script reference in class library

The ScriptIgnoreAttribute class is in the System.Web.Extensions.dll assembly (Located under Assemblies > Framework in the VS Reference Manager). You have to add a reference to that assembly in your class library project.

You can find this information at top of the MSDN page for the ScriptIgnoreAttribute class.

Can not deserialize instance of java.lang.String out of START_ARRAY token

The error is:

Can not deserialize instance of java.lang.String out of START_ARRAY token at [Source: line: 1, column: 1095] (through reference chain: JsonGen["platforms"])

In JSON, platforms look like this:

"platforms": [
    {
        "platform": "iphone"
    },
    {
        "platform": "ipad"
    },
    {
        "platform": "android_phone"
    },
    {
        "platform": "android_tablet"
    }
]

So try change your pojo to something like this:

private List platforms;

public List getPlatforms(){
    return this.platforms;
}

public void setPlatforms(List platforms){
    this.platforms = platforms;
}

EDIT: you will need change mobile_networks too. Will look like this:

private List mobile_networks;

public List getMobile_networks() {
    return mobile_networks;
}

public void setMobile_networks(List mobile_networks) {
    this.mobile_networks = mobile_networks;
}

Add up a column of numbers at the Unix shell

If you have R, you can use:

> ... | Rscript -e 'print(sum(scan("stdin")));'
Read 4 items
[1] 2232320

Since I'm comfortable with R, I actually have several aliases for things like this so I can use them in bash without having to remember this syntax. For instance:

alias Rsum=$'Rscript -e \'print(sum(scan("stdin")));\''

which let's me do

> ... | Rsum
Read 4 items
[1] 2232320

Inspiration: Is there a way to get the min, max, median, and average of a list of numbers in a single command?

Run multiple python scripts concurrently

You try the following ways to run the multiple python scripts:

  import os
  print "Starting script1"
  os.system("python script1.py arg1 arg2 arg3")
  print "script1 ended"
  print "Starting script2"
  os.system("python script2.py arg1 arg2 arg3")
  print "script2 ended"

Note: The execution of multiple scripts depends purely underlined operating system, and it won't be concurrent, I was new comer in Python when I answered it.

Update: I found a package: https://pypi.org/project/schedule/ Above package can be used to run multiple scripts and function, please check this and maybe on weekend will provide some example too.

i.e:

 import schedule
 import time
 import script1, script2

 def job():
     print("I'm working...")

 schedule.every(10).minutes.do(job)
 schedule.every().hour.do(job)
 schedule.every().day.at("10:30").do(job)
 schedule.every(5).to(10).days.do(job)
 schedule.every().monday.do(job)
 schedule.every().wednesday.at("13:15").do(job)

 while True:
     schedule.run_pending()
     time.sleep(1)

curl: (6) Could not resolve host: google.com; Name or service not known

Issues were:

  1. IPV6 enabled
  2. Wrong DNS server

Here is how I fixed it:

IPV6 Disabling

  • Open Terminal
  • Type su and enter to log in as the super user
  • Enter the root password
  • Type cd /etc/modprobe.d/ to change directory to /etc/modprobe.d/
  • Type vi disableipv6.conf to create a new file there
  • Press Esc + i to insert data to file
  • Type install ipv6 /bin/true on the file to avoid loading IPV6 related modules
  • Type Esc + : and then wq for save and exit
  • Type reboot to restart fedora
  • After reboot open terminal and type lsmod | grep ipv6
  • If no result, it means you properly disabled IPV6

Add Google DNS server

  • Open Terminal
  • Type su and enter to log in as the super user
  • Enter the root password
  • Type cat /etc/resolv.conf to check what DNS server your Fedora using. Mostly this will be your Modem IP address.
  • Now we have to Find a powerful DNS server. Luckily there is a open DNS server maintain by Google.
  • Go to this page and find out what are the "Google Public DNS IP addresses"
  • Today those are 8.8.8.8 and 8.8.4.4. But in future those may change.
  • Type vi /etc/resolv.conf to edit the resolv.conf file
  • Press Esc + i for insert data to file
  • Comment all the things in the file by inserting # at the begin of the each line. Do not delete anything because can be useful in future.

  • Type below two lines in the file

    nameserver 8.8.8.8
    nameserver 8.8.4.4

    -Type Esc + : and then wq for save and exit

  • Now you are done and everything works fine (Not necessary to restart).
  • But every time when you restart the computer your /etc/resolv.conf will be replaced by default. So I'll let you find a way to avoid that.

Here is my blog post about this: http://codeketchup.blogspot.sg/2014/07/how-to-fix-curl-6-could-not-resolve.html

How to Execute a Python File in Notepad ++?

In Notepad++, go to Run ? Run..., select the path and idle.py file of your Python installation:

C:\Python27\Lib\idlelib\idle.py

add a space and this:

"$(FULL_CURRENT_PATH)"

and here you are!

Video demostration:

https://www.youtube.com/watch?v=sJipYE1JT38

Find a file with a certain extension in folder

You could use the Directory class

 Directory.GetFiles(path, "*.txt", SearchOption.AllDirectories)

C++ Passing Pointer to Function (Howto) + C++ Pointer Manipulation

It might be easier for you to understand using Functionoids which are expressively neater and more powerful to use, see this excellent and highly recommended C++ FAQ lite, in particular, look at section 33.12 onwards, but nonetheless, read it from the start of that section to gain a grasp and understanding of it.

To answer your question:

typedef void (*foobar)() fubarfn;

void Fun(fubarfn& baz){
   fubarfn = baz;
   baz();
}

Edit:

  • & means the reference address
  • * means the value of what's contained at the reference address, called de-referencing

So using the reference, example below, shows that we are passing in a parameter, and directly modify it.

void FunByRef(int& iPtr){
    iPtr = 2;
}

int main(void){
    // ...
    int n;
    FunByRef(n);
    cout << n << endl; // n will have value of 2
}

Border Radius of Table is not working

This is my solution using the wrapper, just removing border-collapse might not be helpful always, because you might want to have borders.

_x000D_
_x000D_ 
.wrapper {_x000D_
  overflow: auto;_x000D_
  border-radius: 6px;_x000D_
  border: 1px solid red;_x000D_
}_x000D_
_x000D_
table {_x000D_
  border-spacing: 0;_x000D_
  border-collapse: collapse;_x000D_
  border-style: hidden;_x000D_
_x000D_
  width:100%;_x000D_
  max-width: 100%;_x000D_
}_x000D_
_x000D_
th, td {_x000D_
  padding: 10px;_x000D_
  border: 1px solid #CCCCCC;_x000D_
}
_x000D_ 
<div class="wrapper">_x000D_
  <table>_x000D_
    <thead>_x000D_
      <tr>_x000D_
        <th>Column 1</th>_x000D_
        <th>Column 2</th>_x000D_
        <th>Column 3</th>_x000D_
      </tr>_x000D_
    </thead>_x000D_
_x000D_
    <tbody>_x000D_
      <tr>_x000D_
        <td>Foo Bar boo</td>_x000D_
        <td>Lipsum</td>_x000D_
        <td>Beehuum Doh</td>_x000D_
      </tr>_x000D_
      <tr>_x000D_
        <td>Dolor sit</td>_x000D_
        <td>ahmad</td>_x000D_
        <td>Polymorphism</td>_x000D_
      </tr>_x000D_
      <tr>_x000D_
        <td>Kerbalium</td>_x000D_
        <td>Caton, gookame kyak</td>_x000D_
        <td>Corona Premium Beer</td>_x000D_
      </tr>_x000D_
    </tbody>_x000D_
  </table>  _x000D_
</div>
_x000D_
_x000D_
_x000D_

This article helped: https://css-tricks.com/table-borders-inside/

Servlet returns "HTTP Status 404 The requested resource (/servlet) is not available"

Please check context root cannot be empty.

If you're using eclipse:
right click, select properties, then web project settings. Check the context root cannot be empty

How do I print a double value with full precision using cout?

You can set the precision directly on std::cout and use the std::fixed format specifier.

double d = 3.14159265358979;
cout.precision(17);
cout << "Pi: " << fixed << d << endl;

You can #include <limits> to get the maximum precision of a float or double.

#include <limits>

typedef std::numeric_limits< double > dbl;

double d = 3.14159265358979;
cout.precision(dbl::max_digits10);
cout << "Pi: " << d << endl;

How can I print out C++ map values?

 
for(map<string, pair<string,string> >::const_iterator it = myMap.begin();
    it != myMap.end(); ++it)
{
    std::cout << it->first << " " << it->second.first << " " << it->second.second << "\n";
}

In C++11, you don't need to spell out map<string, pair<string,string> >::const_iterator. You can use auto

for(auto it = myMap.cbegin(); it != myMap.cend(); ++it)
{
    std::cout << it->first << " " << it->second.first << " " << it->second.second << "\n";
}

Note the use of cbegin() and cend() functions.

Easier still, you can use the range-based for loop:

for(auto elem : myMap)
{
   std::cout << elem.first << " " << elem.second.first << " " << elem.second.second << "\n";
}

JavaScript editor within Eclipse

Didn't use eclipse for a while, but there are ATF and Aptana.

Show/hide 'div' using JavaScript

Just Simple Function Need To implement Show/hide 'div' using JavaScript

<a id="morelink" class="link-more" style="font-weight: bold; display: block;" onclick="this.style.display='none'; document.getElementById('states').style.display='block'; return false;">READ MORE</a>


<div id="states" style="display: block; line-height: 1.6em;">
 text here text here text here text here text here text here text here text here text here text here text here text here text here text here text here text here text here text here text here text here  
    <a class="link-less" style="font-weight: bold;" onclick="document.getElementById('morelink').style.display='inline-block'; document.getElementById('states').style.display='none'; return false;">LESS INFORMATION</a>
    </div>

How to do a redirect to another route with react-router?

Easiest solution for web!

Up to date 2020
confirmed working with:

"react-router-dom": "^5.1.2"
"react": "^16.10.2"

Use the useHistory() hook!

import React from 'react';
import { useHistory } from "react-router-dom";


export function HomeSection() {
  const history = useHistory();
  const goLogin = () => history.push('login');

  return (
    <Grid>
      <Row className="text-center">          
        <Col md={12} xs={12}>
          <div className="input-group">
            <span className="input-group-btn">
              <button onClick={goLogin} type="button" />
            </span>
          </div>
        </Col>
      </Row>
    </Grid>
  );
}

append multiple values for one key in a dictionary

You can use setdefault. 

for line in list:  
    d.setdefault(year, []).append(value)

This works because setdefault returns the list as well as setting it on the dictionary, and because a list is mutable, appending to the version returned by setdefault is the same as appending it to the version inside the dictionary itself. If that makes any sense.

Custom ImageView with drop shadow

Okay, I don't foresee any more answers on this one, so what I ended up going with for now is just a solution for rectangular images. I've used the following NinePatch:

alt text

along with the appropriate padding in XML:

<ImageView
        android:id="@+id/image_test"
        android:background="@drawable/drop_shadow"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingLeft="6px"
        android:paddingTop="4px"
        android:paddingRight="8px"
        android:paddingBottom="9px"
        android:src="@drawable/pic1"
        />

to get a fairly good result:

alt text

Not ideal, but it'll do.

What are the advantages of NumPy over regular Python lists?

NumPy's arrays are more compact than Python lists -- a list of lists as you describe, in Python, would take at least 20 MB or so, while a NumPy 3D array with single-precision floats in the cells would fit in 4 MB. Access in reading and writing items is also faster with NumPy.

Maybe you don't care that much for just a million cells, but you definitely would for a billion cells -- neither approach would fit in a 32-bit architecture, but with 64-bit builds NumPy would get away with 4 GB or so, Python alone would need at least about 12 GB (lots of pointers which double in size) -- a much costlier piece of hardware!

The difference is mostly due to "indirectness" -- a Python list is an array of pointers to Python objects, at least 4 bytes per pointer plus 16 bytes for even the smallest Python object (4 for type pointer, 4 for reference count, 4 for value -- and the memory allocators rounds up to 16). A NumPy array is an array of uniform values -- single-precision numbers takes 4 bytes each, double-precision ones, 8 bytes. Less flexible, but you pay substantially for the flexibility of standard Python lists!

How to remove backslash on json_encode() function?

As HungryDB said the easier way for do that is:

$mystring = json_encode($my_json,JSON_UNESCAPED_SLASHES);

Have a look at your php version because this parameter has been added in version 5.4.0

json_encode documentation

How to format a Java string with leading zero?

In Java:

String zeroes="00000000";
String apple="apple";

String result=zeroes.substring(apple.length(),zeroes.length())+apple;

In Scala:

"Apple".foldLeft("00000000"){(ac,e)=>ac.tail+e}

You can also explore a way in Java 8 to do it using streams and reduce (similar to the way I did it with Scala). It's a bit different to all the other solutions and I particularly like it a lot.

Given final block not properly padded

This can also be a issue when you enter wrong password for your sign key.

How can I display two div in one line via css inline property

use inline-block instead of inline. Read more information here about the difference between inline and inline-block.

.inline { 
display: inline-block; 
border: 1px solid red; 
margin:10px;
}

DEMO

How to remove all line breaks from a string

On mac, just use \n in regexp to match linebreaks. So the code will be string.replace(/\n/g, ''), ps: the g followed means match all instead of just the first.

On windows, it will be \r\n.

How to set seekbar min and max value

 
    private static final int MIN_METERS = 100;
    private static final int JUMP_BY = 50;

    metersText.setText(meters+"");
    metersBar.setProgress((meters-MIN_METERS));
    metersBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
        @Override
        public void onStopTrackingTouch(SeekBar seekBar) {
            // TODO Auto-generated method stub
        }
        @Override
        public void onStartTrackingTouch(SeekBar seekBar) {
            // TODO Auto-generated method stub
        }
        @Override
        public void onProgressChanged(SeekBar seekBar, int progress,boolean fromUser) {
            progress = progress + MIN_METERS;
            progress = progress / JUMP_BY;
            progress = progress * JUMP_BY;
            metersText.setText((progress)+"");
        }
    });
}

What is and how to fix System.TypeInitializationException error?

i. Please check the InnerException property of the TypeInitializationException

ii. Also, this may occur due to mismatch between the runtime versions of the assemblies. Please verify the runtime versions of the main assembly (calling application) and the referred assembly

Change a Django form field to a hidden field

Firstly, if you don't want the user to modify the data, then it seems cleaner to simply exclude the field. Including it as a hidden field just adds more data to send over the wire and invites a malicious user to modify it when you don't want them to. If you do have a good reason to include the field but hide it, you can pass a keyword arg to the modelform's constructor. Something like this perhaps:

class MyModelForm(forms.ModelForm):
    class Meta:
        model = MyModel
    def __init__(self, *args, **kwargs):
        from django.forms.widgets import HiddenInput
        hide_condition = kwargs.pop('hide_condition',None)
        super(MyModelForm, self).__init__(*args, **kwargs)
        if hide_condition:
            self.fields['fieldname'].widget = HiddenInput()
            # or alternately:  del self.fields['fieldname']  to remove it from the form altogether.

Then in your view:

form = MyModelForm(hide_condition=True)

I prefer this approach to modifying the modelform's internals in the view, but it's a matter of taste.

Pass array to ajax request in $.ajax()

 
info = [];
info[0] = 'hi';
info[1] = 'hello';


$.ajax({
   type: "POST",
   data: {info:info},
   url: "index.php",
   success: function(msg){
     $('.answer').html(msg);
   }
});

NLTK and Stopwords Fail #lookuperror

 
import nltk
nltk.download()

Click on download button when gui prompted. It worked for me.(nltk.download('stopwords') doesn't work for me)

How can I run multiple curl requests processed sequentially?

According to the curl man page:

You can specify any amount of URLs on the command line. They will be fetched in a sequential manner in the specified order.

So the simplest and most efficient (curl will send them all down a single TCP connection [those to the same origin]) approach would be put them all on a single invocation of curl e.g.:

curl http://example.com/?update_=1 http://example.com/?update_=2

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/

Get current AUTO_INCREMENT value for any table

I believe you're looking for MySQL's LAST_INSERT_ID() function. If in the command line, simply run the following:

LAST_INSERT_ID();

You could also obtain this value through a SELECT query:

SELECT LAST_INSERT_ID();

How to create a temporary directory and get the path / file name in Python

To expand on another answer, here is a fairly complete example which can cleanup the tmpdir even on exceptions:

import contextlib
import os
import shutil
import tempfile

@contextlib.contextmanager
def cd(newdir, cleanup=lambda: True):
    prevdir = os.getcwd()
    os.chdir(os.path.expanduser(newdir))
    try:
        yield
    finally:
        os.chdir(prevdir)
        cleanup()

@contextlib.contextmanager
def tempdir():
    dirpath = tempfile.mkdtemp()
    def cleanup():
        shutil.rmtree(dirpath)
    with cd(dirpath, cleanup):
        yield dirpath

def main():
    with tempdir() as dirpath:
        pass # do something here

How to change default format at created_at and updated_at value laravel

You could use

protected $casts = [
    'created_at' => "datetime:Y-m-d\TH:iPZ",
];

in your model class or any format following this link https://www.php.net/manual/en/datetime.format.php

Redirect using AngularJS

Assuming you're not using html5 routing, try $location.path("route"). This will redirect your browser to #/route which might be what you want.

How to add chmod permissions to file in Git?

According to official documentation, you can set or remove the "executable" flag on any tracked file using update-index sub-command.

To set the flag, use following command:

git update-index --chmod=+x path/to/file

To remove it, use:

git update-index --chmod=-x path/to/file

Under the hood

While this looks like the regular unix files permission system, actually it is not. Git maintains a special "mode" for each file in its internal storage:

  • 100644 for regular files
  • 100755 for executable ones

You can visualize it using ls-file subcommand, with --stage option:

$ git ls-files --stage
100644 aee89ef43dc3b0ec6a7c6228f742377692b50484 0       .gitignore
100755 0ac339497485f7cc80d988561807906b2fd56172 0       my_executable_script.sh

By default, when you add a file to a repository, Git will try to honor its filesystem attributes and set the correct filemode accordingly. You can disable this by setting core.fileMode option to false:

git config core.fileMode false

Troubleshooting

If at some point the Git filemode is not set but the file has correct filesystem flag, try to remove mode and set it again:

git update-index --chmod=-x path/to/file
git update-index --chmod=+x path/to/file

Bonus

Starting with Git 2.9, you can stage a file AND set the flag in one command:

git add --chmod=+x path/to/file

How to set UICollectionViewCell Width and Height programmatically

An other way is to set the value directly in the flow layout 

    let layout = collectionView.collectionViewLayout as! UICollectionViewFlowLayout
    layout.itemSize = CGSize(width: size, height: size)

Hive: Filtering Data between Specified Dates when Date is a String

No need to extract the month and year.Just need to use the unix_timestamp(date String,format String) function.

For Example:

select yourdate_column
from your_table
where unix_timestamp(yourdate_column, 'yyyy-MM-dd') >= unix_timestamp('2014-06-02', 'yyyy-MM-dd')
and unix_timestamp(yourdate_column, 'yyyy-MM-dd') <= unix_timestamp('2014-07-02','yyyy-MM-dd')
order by yourdate_column limit 10;

Saving utf-8 texts with json.dumps as UTF8, not as \u escape sequence

Here's my solution using json.dump():

def jsonWrite(p, pyobj, ensure_ascii=False, encoding=SYSTEM_ENCODING, **kwargs):
    with codecs.open(p, 'wb', 'utf_8') as fileobj:
        json.dump(pyobj, fileobj, ensure_ascii=ensure_ascii,encoding=encoding, **kwargs)

where SYSTEM_ENCODING is set to:

locale.setlocale(locale.LC_ALL, '')
SYSTEM_ENCODING = locale.getlocale()[1]

How to use a WSDL

I would fire up Visual Studio, create a web project (or console app - doesn't matter).

For .Net Standard:

  1. I would right-click on the project and pick "Add Service Reference" from the Add context menu.
  2. I would click on Advanced, then click on Add Service Reference.
  3. I would get the complete file path of the wsdl and paste into the address bar. Then fire the Arrow (go button).
  4. If there is an error trying to load the file, then there must be a broken and unresolved url the file needs to resolve as shown below: enter image description here Refer to this answer for information on how to fix: Stackoverflow answer to: Unable to create service reference for wsdl file

If there is no error, you should simply set the NameSpace you want to use to access the service and it'll be generated for you.

For .Net Core

  1. I would right click on the project and pick Connected Service from the Add context menu.
  2. I would select Microsoft WCF Web Service Reference Provider from the list.
  3. I would press browse and select the wsdl file straight away, Set the namespace and I am good to go. Refer to the error fix url above if you encounter any error.

Any of the methods above will generate a simple, very basic WCF client for you to use. You should find a "YourservicenameClient" class in the generated code.

For reference purpose, the generated cs file can be found in your Obj/debug(or release)/XsdGeneratedCode and you can still find the dlls in the TempPE folder.

The created Service(s) should have methods for each of the defined methods on the WSDL contract.

Instantiate the client and call the methods you want to call - that's all there is!

YourServiceClient client = new YourServiceClient();
client.SayHello("World!");

If you need to specify the remote URL (not using the one created by default), you can easily do this in the constructor of the proxy client:

YourServiceClient client = new YourServiceClient("configName", "remoteURL");

where configName is the name of the endpoint to use (you will use all the settings except the URL), and the remoteURL is a string representing the URL to connect to (instead of the one contained in the config).

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

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

How to set breakpoints in inline Javascript in Google Chrome?

Using Visual Studio (2012) I had the same issue and switching to IIS Express solved the problem!

The script tag's type attribute did not factor into it.

For some reason the Visual Studio Development Server does not provide everything Chrome needs to enable the breakpoints.

Is there a good JSP editor for Eclipse?

As well as Amateras you could try Web Tools Project or Aptana. Although they will both give you way more than just a jsp editor.

Edit 2010/10/26 (comment from Simon Gibbs):

The Web Tools Project JSP editor is in the "Web Page Editor (Optional)" project.

Edit 2016/08/16 (extended comment from Dan Carter):

From Kepler (Eclipse 4.3.x) on, this is called "JSF Tools - Web Page Editor".

eclipse

how do I insert a column at a specific column index in pandas?

see docs: http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.insert.html

using loc = 0 will insert at the beginning

df.insert(loc, column, value)

df = pd.DataFrame({'B': [1, 2, 3], 'C': [4, 5, 6]})

df
Out: 
   B  C
0  1  4
1  2  5
2  3  6

idx = 0
new_col = [7, 8, 9]  # can be a list, a Series, an array or a scalar   
df.insert(loc=idx, column='A', value=new_col)

df
Out: 
   A  B  C
0  7  1  4
1  8  2  5
2  9  3  6

Android - default value in editText

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

example:

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

How to implement a confirmation (yes/no) DialogPreference?

That is a simple alert dialog, Federico gave you a site where you can look things up.

Here is a short example of how an alert dialog can be built.

new AlertDialog.Builder(this)
.setTitle("Title")
.setMessage("Do you really want to whatever?")
.setIcon(android.R.drawable.ic_dialog_alert)
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {

    public void onClick(DialogInterface dialog, int whichButton) {
        Toast.makeText(MainActivity.this, "Yaay", Toast.LENGTH_SHORT).show();
    }})
 .setNegativeButton(android.R.string.no, null).show();

java.net.ConnectException: Connection refused

I had the same problem with Mqtt broker called vernemq.but solved it by adding the following.

  1. $ sudo vmq-admin listener show

to show the list o allowed ips and ports for vernemq

  1. $ sudo vmq-admin listener start port=1885 -a 0.0.0.0 --mountpoint /appname --nr_of_acceptors=10 --max_connections=20000

to add any ip and your new port. now u should be able to connect without any problem.

Hope it solves your problem. enter image description here

Grant Select on all Tables Owned By Specific User

Well, it's not a single statement, but it's about as close as you can get with oracle:

BEGIN
   FOR R IN (SELECT owner, table_name FROM all_tables WHERE owner='TheOwner') LOOP
      EXECUTE IMMEDIATE 'grant select on '||R.owner||'.'||R.table_name||' to TheUser';
   END LOOP;
END;

Why are only a few video games written in Java?

Minor points first:

  • any productivity boost from Java is hypothetical. The syntax is almost identical to C++ so you're really just banking on savings from memory management and standard libraries. The libraries have little to offer games developers and memory management is a contentious issue due to garbage collection.

  • cross-platform "for free" is not as good as you think because few developers want to use OpenGL and several key platforms probably lack a good Java implementation or wrappers for their native libraries, whether for graphics, audio, networking, etc.

But mainly, the issue is backwards compatibility. Games developers moved to C++ from C and to C from assembly purely because the migration route was smooth. Each interoperates closely with the previous, and all their previous code was usable in the new language, often via a single compiler. Therefore migration was as slow or as fast as you liked. For example, some of our old headers in use today still have #ifdef WATCOMC in, and I don't think anybody has used the Watcom compiler here in a decade or more. There is a massive investment in old code and each bit is only replaced as needed. That process of replacing and upgrading bits and pieces from one game to the next is nowhere near as practical if you changed to a language that doesn't natively interoperate with your existing code. Yes, C++/Java interoperability is possible, but very impractical by comparison to simply writing "C with a bit of C++" or embedding asm blocks in C.

To properly supercede C++ as the game developers' language of choice, it must do one of two things:

  1. Be easily interoperable with existing legacy code, thus preserving investment and maintaining access to existing libraries and tools, OR
  2. Demonstrably show up-front enough of a productivity boost that the cost of rewriting all your own code (or reworking the interfaces into reusable components that can be used from that language) is more than covered.

Subjectively, I don't think Java meets either of those. A higher-level language might meet the 2nd, if someone is brave enough to be the pioneer. (EVE Online is probably the best example we have of Python being usable, but which uses a fork of the main Python language, many C++ components for performance, and even that is for a fairly undemanding game in modern terms.)

Checking if a textbox is empty in Javascript

onchange will work only if the value of the textbox changed compared to the value it had before, so for the first time it won't work because the state didn't change.

So it is better to use onblur event or on submitting the form.

_x000D_
_x000D_ 
function checkTextField(field) {_x000D_
  document.getElementById("error").innerText =_x000D_
    (field.value === "") ? "Field is empty." : "Field is filled.";_x000D_
}
_x000D_ 
<input type="text" onblur="checkTextField(this);" />_x000D_
<p id="error"></p>
_x000D_
_x000D_
_x000D_

(Or old live demo.)

How to join on multiple columns in Pyspark?

You should use & / | operators and be careful about operator precedence (== has lower precedence than bitwise AND and OR):

df1 = sqlContext.createDataFrame(
    [(1, "a", 2.0), (2, "b", 3.0), (3, "c", 3.0)],
    ("x1", "x2", "x3"))

df2 = sqlContext.createDataFrame(
    [(1, "f", -1.0), (2, "b", 0.0)], ("x1", "x2", "x3"))

df = df1.join(df2, (df1.x1 == df2.x1) & (df1.x2 == df2.x2))
df.show()

## +---+---+---+---+---+---+
## | x1| x2| x3| x1| x2| x3|
## +---+---+---+---+---+---+
## |  2|  b|3.0|  2|  b|0.0|
## +---+---+---+---+---+---+