Programs & Examples On #Countdownlatch

A countdown latch is a synchronization primitive that allows one or more threads to wait until a certain number of operations are completed on other threads.

How is CountDownLatch used in Java Multithreading?

From oracle documentation about CountDownLatch:

A synchronization aid that allows one or more threads to wait until a set of operations being performed in other threads completes.

A CountDownLatch is initialized with a given count. The await methods block until the current count reaches zero due to invocations of the countDown() method, after which all waiting threads are released and any subsequent invocations of await return immediately. This is a one-shot phenomenon -- the count cannot be reset.

A CountDownLatch is a versatile synchronization tool and can be used for a number of purposes.

A CountDownLatch initialized with a count of one serves as a simple on/off latch, or gate: all threads invoking await wait at the gate until it is opened by a thread invoking countDown().

A CountDownLatch initialized to N can be used to make one thread wait until N threads have completed some action, or some action has been completed N times.

public void await()
           throws InterruptedException

Causes the current thread to wait until the latch has counted down to zero, unless the thread is interrupted.

If the current count is zero then this method returns immediately.

public void countDown()

Decrements the count of the latch, releasing all waiting threads if the count reaches zero.

If the current count is greater than zero then it is decremented. If the new count is zero then all waiting threads are re-enabled for thread scheduling purposes.

Explanation of your example.

  1. You have set count as 3 for latch variable

    CountDownLatch latch = new CountDownLatch(3);
    
  2. You have passed this shared latch to Worker thread : Processor

  3. Three Runnable instances of Processor have been submitted to ExecutorService executor
  4. Main thread ( App ) is waiting for count to become zero with below statement

     latch.await();  
    
  5. Processor thread sleeps for 3 seconds and then it decrements count value with latch.countDown()
  6. First Process instance will change latch count as 2 after it's completion due to latch.countDown().

  7. Second Process instance will change latch count as 1 after it's completion due to latch.countDown().

  8. Third Process instance will change latch count as 0 after it's completion due to latch.countDown().

  9. Zero count on latch causes main thread App to come out from await

  10. App program prints this output now : Completed

How to show a dialog to confirm that the user wishes to exit an Android Activity?

I'd prefer to exit with double tap on the back button than with an exit Dialog.

In this solution, it show a toast when go back for the first time, warning that another back press will close the App. In this example less than 4 seconds.

private Toast toast;
private long lastBackPressTime = 0;

@Override
public void onBackPressed() {
  if (this.lastBackPressTime < System.currentTimeMillis() - 4000) {
    toast = Toast.makeText(this, "Press back again to close this app", 4000);
    toast.show();
    this.lastBackPressTime = System.currentTimeMillis();
  } else {
    if (toast != null) {
    toast.cancel();
  }
  super.onBackPressed();
 }
}

Token from: http://www.androiduipatterns.com/2011/03/back-button-behavior.html

How to get memory available or used in C#

System.Environment has WorkingSet- a 64-bit signed integer containing the number of bytes of physical memory mapped to the process context.

If you want a lot of details there is System.Diagnostics.PerformanceCounter, but it will be a bit more effort to setup.

Pandas : compute mean or std (standard deviation) over entire dataframe

You could convert the dataframe to be a single column with stack (this changes the shape from 5x3 to 15x1) and then take the standard deviation:

df.stack().std()         # pandas default degrees of freedom is one

Alternatively, you can use values to convert from a pandas dataframe to a numpy array before taking the standard deviation:

df.values.std(ddof=1)    # numpy default degrees of freedom is zero

Unlike pandas, numpy will give the standard deviation of the entire array by default, so there is no need to reshape before taking the standard deviation.

A couple of additional notes:

  • The numpy approach here is a bit faster than the pandas one, which is generally true when you have the option to accomplish the same thing with either numpy or pandas. The speed difference will depend on the size of your data, but numpy was roughly 10x faster when I tested a few different sized dataframes on my laptop (numpy version 1.15.4 and pandas version 0.23.4).

  • The numpy and pandas approaches here will not give exactly the same answers, but will be extremely close (identical at several digits of precision). The discrepancy is due to slight differences in implementation behind the scenes that affect how the floating point values get rounded.

Accessing a resource via codebehind in WPF

If you want to access a resource from some other class (i.g. not a xaml codebehind), you can use

Application.Current.Resources["resourceName"];

from System.Windows namespace.

How to add 30 minutes to a JavaScript Date object?

You could do this:

_x000D_
_x000D_
let thirtyMinutes = 30 * 60 * 1000; // convert 30 minutes to milliseconds_x000D_
let date1 = new Date();_x000D_
let date2 = new Date(date1.getTime() + thirtyMinutes);_x000D_
console.log(date1);_x000D_
console.log(date2);
_x000D_
_x000D_
_x000D_

Java program to find the largest & smallest number in n numbers without using arrays

import java.util.Scanner;

public class LargestSmallestNumbers {

    private static Scanner input;

    public static void main(String[] args) {
       int count,items;
       int newnum =0 ;
       int highest=0;
       int lowest =0;

       input = new Scanner(System.in);
       System.out.println("How many numbers you want to enter?");
       items = input.nextInt();

       System.out.println("Enter "+items+" numbers: ");


       for (count=0; count<items; count++){
           newnum = input.nextInt();               
           if (highest<newnum)
               highest=newnum;

           if (lowest==0)
               lowest=newnum;

           else if (newnum<=lowest)
               lowest=newnum;
           }

       System.out.println("The highest number is "+highest);
       System.out.println("The lowest number is "+lowest);
    }
}

python exception message capturing

You can try specifying the BaseException type explicitly. However, this will only catch derivatives of BaseException. While this includes all implementation-provided exceptions, it is also possibly to raise arbitrary old-style classes.

try:
  do_something()
except BaseException, e:
  logger.error('Failed to do something: ' + str(e))

IOS 7 Navigation Bar text and arrow color

It seems that Accessibility controls in the iOS Settings override pretty much everything you try to do color-wise to the navigation bar buttons. Make sure you have all the settings to the default positions (set increase contrast, bold text, button shapes, etc to off) otherwise you won't see anything change. Once I did it, all the color change code started working as expected. You might not need to turn them all off, but I didn't pursue it further.

How to transfer paid android apps from one google account to another google account

It's totally feasible now. Google now allow you to transfer Android apps between accounts. Please take a look at this link: https://support.google.com/googleplay/android-developer/checklist/3294213?hl=en

How to match a substring in a string, ignoring case

import re
if re.search('(?i)Mandy Pande:', line):
    ...

Python, how to check if a result set is empty?

Notice: This is for MySQLdb module in Python.

For a SELECT statement, there shouldn't be an exception for an empty recordset. Just an empty list ([]) for cursor.fetchall() and None for cursor.fetchone().

For any other statement, e.g. INSERT or UPDATE, that doesn't return a recordset, you can neither call fetchall() nor fetchone() on the cursor. Otherwise, an exception will be raised.

There's one way to distinguish between the above two types of cursors:

def yield_data(cursor):
    while True:
        if cursor.description is None:
            # No recordset for INSERT, UPDATE, CREATE, etc
            pass
        else:
            # Recordset for SELECT, yield data
            yield cursor.fetchall()
            # Or yield column names with
            # yield [col[0] for col in cursor.description]

        # Go to the next recordset
        if not cursor.nextset():
            # End of recordsets
            return

How to resolve Nodejs: Error: ENOENT: no such file or directory

I solved this error by simply creating a blank file at that location for which I got the error. If you are getting the error for a directory, You can try by creating empty directory also. All the best.

Hexadecimal string to byte array in C

I found this question by Googling for the same thing. I don't like the idea of calling sscanf() or strtol() since it feels like overkill. I wrote a quick function which does not validate that the text is indeed the hexadecimal presentation of a byte stream, but will handle odd number of hex digits:

uint8_t tallymarker_hextobin(const char * str, uint8_t * bytes, size_t blen)
{
   uint8_t  pos;
   uint8_t  idx0;
   uint8_t  idx1;

   // mapping of ASCII characters to hex values
   const uint8_t hashmap[] =
   {
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, //  !"#$%&'
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ()*+,-./
     0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, // 01234567
     0x08, 0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 89:;<=>?
     0x00, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x00, // @ABCDEFG
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // HIJKLMNO
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // PQRSTUVW
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // XYZ[\]^_
     0x00, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x00, // `abcdefg
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // hijklmno
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // pqrstuvw
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // xyz{|}~.
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00  // ........
   };

   bzero(bytes, blen);
   for (pos = 0; ((pos < (blen*2)) && (pos < strlen(str))); pos += 2)
   {
      idx0 = (uint8_t)str[pos+0];
      idx1 = (uint8_t)str[pos+1];
      bytes[pos/2] = (uint8_t)(hashmap[idx0] << 4) | hashmap[idx1];
   };

   return(0);
}

How to configure Spring Security to allow Swagger URL to be accessed without authentication

Adding this to your WebSecurityConfiguration class should do the trick.

@Configuration
public class WebSecurityConfiguration extends WebSecurityConfigurerAdapter {

    @Override
    public void configure(WebSecurity web) throws Exception {
        web.ignoring().antMatchers("/v2/api-docs",
                                   "/configuration/ui",
                                   "/swagger-resources/**",
                                   "/configuration/security",
                                   "/swagger-ui.html",
                                   "/webjars/**");
    }

}

Pass Javascript variable to PHP via ajax

Alternatively, try removing "data" and making the URL "logtime.php?userID="+userId

I like Brian's answer better, this answer is just because you're trying to use URL parameter syntax in "data" and I wanted to demonstrate where you can use that syntax correctly.

For..In loops in JavaScript - key value pairs

for...in will work for you.

for( var key in obj ) {
  var value = obj[key];
}

In modern JavaScript you can also do this:

for ( const [key,value] of Object.entries( obj ) ) {

}

Twig ternary operator, Shorthand if-then-else

You can use shorthand syntax as of Twig 1.12.0

{{ foo ?: 'no' }} is the same as {{ foo ? foo : 'no' }}
{{ foo ? 'yes' }} is the same as {{ foo ? 'yes' : '' }}

How to get the host name of the current machine as defined in the Ansible hosts file?

The necessary variable is inventory_hostname.

- name: Install this only for local dev machine
  pip: name=pyramid
  when: inventory_hostname == "local"

It is somewhat hidden in the documentation at the bottom of this section.

How to align a div inside td element using CSS class

div { margin: auto; }

This will center your div.

Div by itself is a blockelement. Therefor you need to define the style to the div how to behave.

Is it possible to ping a server from Javascript?

You can run the DOS ping.exe command from javaScript using the folowing:

function ping(ip)
{
    var input = "";
    var WshShell = new ActiveXObject("WScript.Shell");
    var oExec = WshShell.Exec("c:/windows/system32/ping.exe " + ip);

    while (!oExec.StdOut.AtEndOfStream)
    {
            input += oExec.StdOut.ReadLine() + "<br />";
    }
    return input;
}

Is this what was asked for, or am i missing something?

Call removeView() on the child's parent first

Ok, call me paranoid but I suggest:

  final android.view.ViewParent parent = view.getParent ();

  if (parent instanceof android.view.ViewManager)
  {
     final android.view.ViewManager viewManager = (android.view.ViewManager) parent;

     viewManager.removeView (view);
  } // if

casting without instanceof just seems wrong. And (thanks IntelliJ IDEA for telling me) removeView is part of the ViewManager interface. And one should not cast to a concrete class when a perfectly suitable interface is available.

How to `wget` a list of URLs in a text file?

If you also want to preserve the original file name, try with:

wget --content-disposition --trust-server-names -i list_of_urls.txt

Is there a short contains function for lists?

I came up with this one liner recently for getting True if a list contains any number of occurrences of an item, or False if it contains no occurrences or nothing at all. Using next(...) gives this a default return value (False) and means it should run significantly faster than running the whole list comprehension.

list_does_contain = next((True for item in list_to_test if item == test_item), False)

How to Generate Unique Public and Private Key via RSA

What I ended up doing is create a new KeyContainer name based off of the current DateTime (DateTime.Now.Ticks.ToString()) whenever I need to create a new key and save the container name and public key to the database. Also, whenever I create a new key I would do the following:

public static string ConvertToNewKey(string oldPrivateKey)
{

    // get the current container name from the database...

    rsa.PersistKeyInCsp = false;
    rsa.Clear();
    rsa = null;

    string privateKey = AssignNewKey(true); // create the new public key and container name and write them to the database...

       // re-encrypt existing data to use the new keys and write to database...

    return privateKey;
}
public static string AssignNewKey(bool ReturnPrivateKey){
     string containerName = DateTime.Now.Ticks.ToString();
     // create the new key...
     // saves container name and public key to database...
     // and returns Private Key XML.
}

before creating the new key.

An efficient way to Base64 encode a byte array?

Here is the code to base64 encode directly to byte array (tested to be performing +-10% of .Net Implementation, but allocates half the memory):

    static public void testBase64EncodeToBuffer()
    {
        for (int i = 1; i < 200; ++i)
        {
            // prep test data
            byte[] testData = new byte[i];
            for (int j = 0; j < i; ++j)
                testData[j] = (byte)(j ^ i);

            // test
            testBase64(testData);
        }
    }

    static void testBase64(byte[] data)
    {
        if (!appendBase64(data, 0, data.Length, false).SequenceEqual(System.Text.Encoding.ASCII.GetBytes(Convert.ToBase64String(data)))) throw new Exception("Base 64 encoding failed");
    }

    static public byte[] appendBase64(byte[] data
                              , int offset
                              , int size
                              , bool addLineBreaks = false)
    {
        byte[] buffer;
        int bufferPos = 0;
        int requiredSize = (4 * ((size + 2) / 3));
        // size/76*2 for 2 line break characters    
        if (addLineBreaks) requiredSize += requiredSize + (requiredSize / 38);

        buffer = new byte[requiredSize];

        UInt32 octet_a;
        UInt32 octet_b;
        UInt32 octet_c;
        UInt32 triple;
        int lineCount = 0;
        int sizeMod = size - (size % 3);
        // adding all data triplets
        for (; offset < sizeMod;)
        {
            octet_a = data[offset++];
            octet_b = data[offset++];
            octet_c = data[offset++];

            triple = (octet_a << 0x10) + (octet_b << 0x08) + octet_c;

            buffer[bufferPos++] = base64EncodingTable[(triple >> 3 * 6) & 0x3F];
            buffer[bufferPos++] = base64EncodingTable[(triple >> 2 * 6) & 0x3F];
            buffer[bufferPos++] = base64EncodingTable[(triple >> 1 * 6) & 0x3F];
            buffer[bufferPos++] = base64EncodingTable[(triple >> 0 * 6) & 0x3F];
            if (addLineBreaks)
            {
                if (++lineCount == 19)
                {
                    buffer[bufferPos++] = 13;
                    buffer[bufferPos++] = 10;
                    lineCount = 0;
                }
            }
        }

        // last bytes
        if (sizeMod < size)
        {
            octet_a = offset < size ? data[offset++] : (UInt32)0;
            octet_b = offset < size ? data[offset++] : (UInt32)0;
            octet_c = (UInt32)0; // last character is definitely padded

            triple = (octet_a << 0x10) + (octet_b << 0x08) + octet_c;

            buffer[bufferPos++] = base64EncodingTable[(triple >> 3 * 6) & 0x3F];
            buffer[bufferPos++] = base64EncodingTable[(triple >> 2 * 6) & 0x3F];
            buffer[bufferPos++] = base64EncodingTable[(triple >> 1 * 6) & 0x3F];
            buffer[bufferPos++] = base64EncodingTable[(triple >> 0 * 6) & 0x3F];

            // add padding '='
            sizeMod = size % 3;
            // last character is definitely padded
            buffer[bufferPos - 1] = (byte)'=';
            if (sizeMod == 1) buffer[bufferPos - 2] = (byte)'=';
        }
        return buffer;
    }

Running unittest with typical test directory structure

This way will let you run the test scripts from wherever you want without messing around with system variables from the command line.

This adds the main project folder to the python path, with the location found relative to the script itself, not relative to the current working directory.

import sys, os

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.realpath(__file__))))

Add that to the top of all your test scripts. That will add the main project folder to the system path, so any module imports that work from there will now work. And it doesn't matter where you run the tests from.

You can obviously change the project_path_hack file to match your main project folder location.

Save the console.log in Chrome to a file

On Linux (at least) you can set CHROME_LOG_FILE in the environment to have chrome write a log of the Console activity to the named file each time it runs. The log is overwritten every time chrome starts. This way, if you have an automated session that runs chrome, you don't have a to change the way chrome is started, and the log is there after the session ends.

export CHROME_LOG_FILE=chrome.log

How can I get the current class of a div with jQuery?

From now on is better to use the .prop() function instead of the .attr() one.

Here the jQuery documentation:

As of jQuery 1.6, the .attr() method returns undefined for attributes that have not been set. In addition, .attr() should not be used on plain objects, arrays, the window, or the document. To retrieve and change DOM properties, use the .prop() method.

var div1Class = $('#div1').prop('class');

What is the difference between .text, .value, and .value2?

Except first answer form Bathsheba, except MSDN information for:

.Value
.Value2
.Text

you could analyse these tables for better understanding of differences between analysed properties.

enter image description here

Access properties file programmatically with Spring?

How about PropertiesLoaderUtils?

Resource resource = new ClassPathResource("/my.properties");
Properties props = PropertiesLoaderUtils.loadProperties(resource);

How to install Openpyxl with pip

For me it worked as Kumar Jaggal but: steps 1, 2, 3, the same 4. py -m setup.py install

Getting unix timestamp from Date()

I dont know if you want to achieve that in js or java, in js the simplest way to get the unix timestampt (this is time in seconds from 1/1/1970) it's as follows:

var myDate = new Date();
console.log(+myDate); // +myDateObject give you the unix from that date

SOAP or REST for Web Services?

Don't overlook XML-RPC. If you're just after a lightweight solution then there's a great deal to be said for a protocol that can be defined in a couple of pages of text and implemented in a minimal amount of code. XML-RPC has been around for years but went out of fashion for a while - but the minimalist appeal seems to be giving it something of a revival of late.

How to print an unsigned char in C?

The range of char is 127 to -128. If you assign 212, ch stores -44 (212-128-128) not 212.So if you try to print a negative number as unsigned you get (MAX value of unsigned int)-abs(number) which in this case is 4294967252

So if you want to store 212 as it is in ch the only thing you can do is declare ch as

unsigned char ch;

now the range of ch is 0 to 255.

google-services.json for different productFlavors

So if you want to programmatically copy google-services.json file from all your variants into your root folder. When you switch to a specific variant here's a solution for you

android {
  applicationVariants.all { variant ->
    copy {
        println "Switches to $variant google-services.json"
        from "src/$variant"
        include "google-services.json"
        into "."
    }
  }
}

There's a caveat to this approach that is you need to have google-service.json file in each of your variants folder here's an example. variant image

SQL Server Operating system error 5: "5(Access is denied.)"

To get around the access denied issue, I started SSMS as administrator and that allowed me to attach a database from my local drive. The database was created in another SQL and windows instance.

Pass array to ajax request in $.ajax()

NOTE: Doesn't work on newer versions of jQuery.

Since you are using jQuery please use it's seralize function to serialize data and then pass it into the data parameter of ajax call:

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

var data_to_send = $.serialize(info);

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

How to pass an array into a SQL Server stored procedure

Based on my experience, by creating a delimited expression from the employeeIDs, there is a tricky and nice solution for this problem. You should only create an string expression like ';123;434;365;' in-which 123, 434 and 365 are some employeeIDs. By calling the below procedure and passing this expression to it, you can fetch your desired records. Easily you can join the "another table" into this query. This solution is suitable in all versions of SQL server. Also, in comparison with using table variable or temp table, it is very faster and optimized solution.

CREATE PROCEDURE dbo.DoSomethingOnSomeEmployees  @List AS varchar(max)
AS
BEGIN
  SELECT EmployeeID 
  FROM EmployeesTable
  -- inner join AnotherTable on ...
  where @List like '%;'+cast(employeeID as varchar(20))+';%'
END
GO

Winforms TableLayoutPanel adding rows programmatically

It's a weird design, but the TableLayoutPanel.RowCount property doesn't reflect the count of the RowStyles collection, and similarly for the ColumnCount property and the ColumnStyles collection.

What I've found I needed in my code was to manually update RowCount/ColumnCount after making changes to RowStyles/ColumnStyles.

Here's an example of code I've used:

    /// <summary>
    /// Add a new row to our grid.
    /// </summary>
    /// The row should autosize to match whatever is placed within.
    /// <returns>Index of new row.</returns>
    public int AddAutoSizeRow()
    {
        Panel.RowStyles.Add(new RowStyle(SizeType.AutoSize));
        Panel.RowCount = Panel.RowStyles.Count;
        mCurrentRow = Panel.RowCount - 1;
        return mCurrentRow;
    }

Other thoughts

  • I've never used DockStyle.Fill to make a control fill a cell in the Grid; I've done this by setting the Anchors property of the control.

  • If you're adding a lot of controls, make sure you call SuspendLayout and ResumeLayout around the process, else things will run slow as the entire form is relaid after each control is added.

MySQL the right syntax to use near '' at line 1 error

the problem is because you have got the query over multiple lines using the " " that PHP is actually sending all the white spaces in to MySQL which is causing it to error out.

Either put it on one line or append on each line :o)

Sqlyog must be trimming white spaces on each line which explains why its working.

Example:

$qr2="INSERT INTO wp_bp_activity
      (
            user_id,
 (this stuff)component,
     (is)      `type`,
    (a)        `action`,
  (problem)  content,
             primary_link,
             item_id,....

How to extract multiple JSON objects from one file?

Added streaming support based on the answer of @dunes:

import re
from json import JSONDecoder, JSONDecodeError

NOT_WHITESPACE = re.compile(r"[^\s]")


def stream_json(file_obj, buf_size=1024, decoder=JSONDecoder()):
    buf = ""
    ex = None
    while True:
        block = file_obj.read(buf_size)
        if not block:
            break
        buf += block
        pos = 0
        while True:
            match = NOT_WHITESPACE.search(buf, pos)
            if not match:
                break
            pos = match.start()
            try:
                obj, pos = decoder.raw_decode(buf, pos)
            except JSONDecodeError as e:
                ex = e
                break
            else:
                ex = None
                yield obj
        buf = buf[pos:]
    if ex is not None:
        raise ex

How to use ConcurrentLinkedQueue?

This is probably what you're looking for in terms of thread safety & "prettyness" when trying to consume everything in the queue:

for (YourObject obj = queue.poll(); obj != null; obj = queue.poll()) {
}

This will guarantee that you quit when the queue is empty, and that you continue to pop objects off of it as long as it's not empty.

How can I upgrade NumPy?

Because we have two NumPy installations in the system. One is installed by Homebrew and the second is installed by pip. So in order to solve the problem, we need to delete one and use the default NumPy install by OpenCV.

Check the path,

import numpy
print numpy.__path__

and manually delete it using rm.

java.math.BigInteger cannot be cast to java.lang.Long

Your error might be in this line:

List<Long> result = query.list();

where query.list() is returning a BigInteger List instead of Long list. Try to change it to.

List<BigInteger> result = query.list();

System.Windows.Markup.XamlParseException' occurred in PresentationFramework.dll?

When I had this problem, I had literally just forgot to fill in a parameter value in the XAML of the code.

For some reason though, the exception would send me to the CS of the WPF program rather than the XAML. No idea why.

boolean in an if statement

I think that your reasoning is sound. But in practice I have found that it is far more common to omit the === comparison. I think that there are three reasons for that:

  1. It does not usually add to the meaning of the expression - that's in cases where the value is known to be boolean anyway.
  2. Because there is a great deal of type-uncertainty in JavaScript, forcing a type check tends to bite you when you get an unexpected undefined or null value. Often you just want your test to fail in such cases. (Though I try to balance this view with the "fail fast" motto).
  3. JavaScript programmers like to play fast-and-loose with types - especially in boolean expressions - because we can.

Consider this example:

var someString = getInput();
var normalized = someString && trim(someString);  
// trim() removes leading and trailing whitespace

if (normalized) {
    submitInput(normalized);
}

I think that this kind of code is not uncommon. It handles cases where getInput() returns undefined, null, or an empty string. Due to the two boolean evaluations submitInput() is only called if the given input is a string that contains non-whitespace characters.

In JavaScript && returns its first argument if it is falsy or its second argument if the first argument is truthy; so normalized will be undefined if someString was undefined and so forth. That means that none of the inputs to the boolean expressions above are actually boolean values.

I know that a lot of programmers who are accustomed to strong type-checking cringe when seeing code like this. But note applying strong typing would likely require explicit checks for null or undefined values, which would clutter up the code. In JavaScript that is not needed.

Artisan migrate could not find driver

whilst sometimes you might have multiple php versions, you might also have a held-back version of php-mysql.. do a sudo dpkg -l | grep mysql | grep php and compare what you get from php -v

Get IFrame's document, from JavaScript in main document

The problem is that in IE (which is what I presume you're testing in), the <iframe> element has a document property that refers to the document containing the iframe, and this is getting used before the contentDocument or contentWindow.document properties. What you need is:

function GetDoc(x) {
    return x.contentDocument || x.contentWindow.document;
}

Also, document.all is not available in all browsers and is non-standard. Use document.getElementById() instead.

Change a Git remote HEAD to point to something besides master

See: http://www.kernel.org/pub/software/scm/git/docs/git-symbolic-ref.html

This sets the default branch in the git repository. You can run this in bare or mirrored repositories.

Usage:

$ git symbolic-ref HEAD refs/heads/<branch name>

How to change navigation bar color in iOS 7 or 6?

The complete code with version checking.

 if (NSFoundationVersionNumber > NSFoundationVersionNumber_iOS_6_1) {

    // do stuff for iOS 7 and newer
    [self.navigationController.navigationBar setBarTintColor:[UIColor yellowColor]];
}
else {

    // do stuff for older versions than iOS 7
    [self.navigationController.navigationBar setTintColor:[UIColor yellowColor]];
}

How to get Android GPS location

Excerpt:-

try 
        {
          cnt++;scnt++;now=System.currentTimeMillis();r=rand.nextInt(6);r++;
            loc=lm.getLastKnownLocation(best);
            if(loc!=null){lat=loc.getLatitude();lng=loc.getLongitude();}

            Thread.sleep(100);
            handler.sendMessage(handler.obtainMessage());
         } 
        catch (InterruptedException e) 
        {
            Toast.makeText(this, "Error="+e.toString(), Toast.LENGTH_LONG).show();
        }

As you can see above, a thread is running alongside main thread of user-interface activity which continuously displays GPS lat,long alongwith current time and a random dice throw.

IF you are curious then just check the full code: GPS Location with a randomized dice throw & current time in separate thread

Place API key in Headers or URL

I would not put the key in the url, as it does violate this loose 'standard' that is REST. However, if you did, I would place it in the 'user' portion of the url.

eg: http://[email protected]/myresource/myid

This way it can also be passed as headers with basic-auth.

Converting from IEnumerable to List

I use an extension method for this. My extension method first checks to see if the enumeration is null and if so creates an empty list. This allows you to do a foreach on it without explicitly having to check for null.

Here is a very contrived example:

IEnumerable<string> stringEnumerable = null;
StringBuilder csv = new StringBuilder();
stringEnumerable.ToNonNullList().ForEach(str=> csv.Append(str).Append(","));

Here is the extension method:

public static List<T> ToNonNullList<T>(this IEnumerable<T> obj)
{
    return obj == null ? new List<T>() : obj.ToList();
}

How to properly override clone method?

public class MyObject implements Cloneable, Serializable{   

    @Override
    @SuppressWarnings(value = "unchecked")
    protected MyObject clone(){
        ObjectOutputStream oos = null;
        ObjectInputStream ois = null;
        try {
            ByteArrayOutputStream bOs = new ByteArrayOutputStream();
            oos = new ObjectOutputStream(bOs);
            oos.writeObject(this);
            ois = new ObjectInputStream(new ByteArrayInputStream(bOs.toByteArray()));
            return  (MyObject)ois.readObject();

        } catch (Exception e) {
            //Some seriouse error :< //
            return null;
        }finally {
            if (oos != null)
                try {
                    oos.close();
                } catch (IOException e) {

                }
            if (ois != null)
                try {
                    ois.close();
                } catch (IOException e) {

                }
        }
    }
}

jQuery: Check if special characters exists in string

If you really want to check for all those special characters, it's easier to use a regular expression:

var str = $('#Search').val();
if(/^[a-zA-Z0-9- ]*$/.test(str) == false) {
    alert('Your search string contains illegal characters.');
}

The above will only allow strings consisting entirely of characters on the ranges a-z, A-Z, 0-9, plus the hyphen an space characters. A string containing any other character will cause the alert.

Maven plugin not using Eclipse's proxy settings

Eclipse by default does not know about your external Maven installation and uses the embedded one. Therefore in order for Eclipse to use your global settings you need to set it in menu Settings ? Maven ? Installations.

Scroll RecyclerView to show selected item on top

If you want to scroll automatic without show scroll motion then you need to write following code:

mRecyclerView.getLayoutManager().scrollToPosition(position);

If you want to display scroll motion then you need to add following code. =>Step 1: You need to declare SmoothScroller.

RecyclerView.SmoothScroller smoothScroller = new
                LinearSmoothScroller(this.getApplicationContext()) {
                    @Override
                    protected int getVerticalSnapPreference() {
                        return LinearSmoothScroller.SNAP_TO_START;
                    }
                };

=>step 2: You need to add this code any event you want to perform scroll to specific position. =>First you need to set target position to SmoothScroller.

smoothScroller.setTargetPosition(position);

=>Then you need to set SmoothScroller to LayoutManager.

mRecyclerView.getLayoutManager().startSmoothScroll(smoothScroller);

What REST PUT/POST/DELETE calls should return by a convention?

Forgive the flippancy, but if you are doing REST over HTTP then RFC7231 describes exactly what behaviour is expected from GET, PUT, POST and DELETE.

Update (Jul 3 '14):
The HTTP spec intentionally does not define what is returned from POST or DELETE. The spec only defines what needs to be defined. The rest is left up to the implementer to choose.

I didn't find "ZipFile" class in the "System.IO.Compression" namespace

System.IO.Compression is now available as a nuget package maintained by Microsoft.

To use ZipFile you need to download System.IO.Compression.ZipFile nuget package.

jQuery checkbox check/uncheck

Use prop() instead of attr() to set the value of checked. Also use :checkbox in find method instead of input and be specific.

Live Demo

$("#news_list tr").click(function() {
    var ele = $(this).find('input');
    if(ele.is(':checked')){
        ele.prop('checked', false);
        $(this).removeClass('admin_checked');
    }else{
        ele.prop('checked', true);
        $(this).addClass('admin_checked');
    }
});

Use prop instead of attr for properties like checked

As of jQuery 1.6, the .attr() method returns undefined for attributes that have not been set. To retrieve and change DOM properties such as the checked, selected, or disabled state of form elements, use the .prop() method

How can I start PostgreSQL server on Mac OS X?

When you install PostgreSQL using Homebrew,

brew install postgres

at the end of the output, you will see this methods to start the server:

To have launchd start postgresql at login:
    ln -sfv /usr/local/opt/postgresql/*.plist ~/Library/LaunchAgents
Then to load postgresql now:
    launchctl load ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
Or, if you don't want/need launchctl, you can just run:
    postgres -D /usr/local/var/postgres

I think this is the best way.

You can add an alias into your .profile file for convenience.

How do I get whole and fractional parts from double in JSP/Java?

http://www.java2s.com/Code/Java/Data-Type/Obtainingtheintegerandfractionalparts.htm

double num;
long iPart;
double fPart;

// Get user input
num = 2.3d;
iPart = (long) num;
fPart = num - iPart;
System.out.println("Integer part = " + iPart);
System.out.println("Fractional part = " + fPart);

Outputs:

Integer part = 2
Fractional part = 0.2999999999999998

How to restore PostgreSQL dump file into Postgres databases?

You didn't mention how your backup was made, so the generic answer is: Usually with the psql tool.

Depending on what pg_dump was instructed to dump, the SQL file can have different sets of SQL commands. For example, if you instruct pg_dump to dump a database using --clean and --schema-only, you can't expect to be able to restore the database from that dump as there will be no SQL commands for COPYing (or INSERTing if --inserts is used ) the actual data in the tables. A dump like that will contain only DDL SQL commands, and will be able to recreate the schema but not the actual data.

A typical SQL dump is restored with psql:

psql (connection options here) database  < yourbackup.sql

or alternatively from a psql session,

psql (connection options here) database
database=# \i /path/to/yourbackup.sql

In the case of backups made with pg_dump -Fc ("custom format"), which is not a plain SQL file but a compressed file, you need to use the pg_restore tool.

If you're working on a unix-like, try this:

man psql
man pg_dump
man pg_restore

otherwise, take a look at the html docs. Good luck!

What is aria-label and how should I use it?

It's an attribute designed to help assistive technology (e.g. screen readers) attach a label to an otherwise anonymous HTML element.

So there's the <label> element:

<label for="fmUserName">Your name</label>
<input id="fmUserName">

The <label> explicitly tells the user to type their name into the input box where id="fmUserName".

aria-label does much the same thing, but it's for those cases where it isn't practical or desirable to have a label on screen. Take the MDN example:

<button aria-label="Close" onclick="myDialog.close()">X</button>`

Most people would be able to infer visually that this button will close the dialog. A blind person using assistive technology might just hear "X" read aloud, which doesn't mean much without the visual clues. aria-label explicitly tells them what the button will do.

How to do a JUnit assert on a message in a logger

Using Jmockit (1.21) I was able to write this simple test. The test makes sure a specific ERROR message is called just once.

@Test
public void testErrorMessage() {
    final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger( MyConfig.class );

    new Expectations(logger) {{
        //make sure this error is happens just once.
        logger.error( "Something went wrong..." );
        times = 1;
    }};

    new MyTestObject().runSomethingWrong( "aaa" ); //SUT that eventually cause the error in the log.    
}

Android Writing Logs to text File

I have created a simple, lightweight class (about 260 LoC) that extends the standard android.util.Log implementation with file based logging:
Every log message is logged via android.util.Log and also written to a text file on the device.

You can find it on github:
https://github.com/volkerv/FileLog

How to create a link to a directory

Symbolic or soft link (files or directories, more flexible and self documenting)

#     Source                             Link
ln -s /home/jake/doc/test/2000/something /home/jake/xxx

Hard link (files only, less flexible and not self documenting)

#   Source                             Link
ln /home/jake/doc/test/2000/something /home/jake/xxx

More information: man ln


/home/jake/xxx is like a new directory. To avoid "is not a directory: No such file or directory" error, as @trlkly comment, use relative path in the target, that is, using the example:

  1. cd /home/jake/
  2. ln -s /home/jake/doc/test/2000/something xxx

OS X Terminal shortcut: Jump to beginning/end of line

Here I found a tweak for this, without any third party tool. This will make the following shortcut to work:

 fn + right: to go to the end of the line.
 fn + left: to go to the beginning of the line.
  • Open terminal preferences.(cmd + ,).
  • Go to your selected theme and then to the keyboard tab.

enter image description here

  • And add a new entry as following. enter image description here enter image description here

  • That's all. Now close and check.

    Hope it helps.

EDIT: Refer to the comment by @Maurice Gilden below for more insights.

Change the location of the ~ directory in a Windows install of Git Bash

Instead of modifying the global profile you could create the .bash_profile in your default $HOME directory (e.g. C:\Users\WhateverUser\.bash_profile) with the following contents:

export HOME="C:\my\projects\dir"
cd "$HOME" # if you'd like it to be the starting dir of the git shell

How to generate a GUID in Oracle?

You can use the SYS_GUID() function to generate a GUID in your insert statement:

insert into mytable (guid_col, data) values (sys_guid(), 'xxx');

The preferred datatype for storing GUIDs is RAW(16).

As Gopinath answer:

 select sys_guid() from dual
 union all
 select sys_guid() from dual
 union all 
 select sys_guid() from dual

You get

88FDC68C75DDF955E040449808B55601
88FDC68C75DEF955E040449808B55601
88FDC68C75DFF955E040449808B55601

As Tony Andrews says, differs only at one character

88FDC68C75DDF955E040449808B55601
88FDC68C75DEF955E040449808B55601
88FDC68C75DFF955E040449808B55601

Maybe useful: http://feuerthoughts.blogspot.com/2006/02/watch-out-for-sequential-oracle-guids.html

Open Url in default web browser

You should use Linking.

Example from the docs:

class OpenURLButton extends React.Component {
  static propTypes = { url: React.PropTypes.string };
  handleClick = () => {
    Linking.canOpenURL(this.props.url).then(supported => {
      if (supported) {
        Linking.openURL(this.props.url);
      } else {
        console.log("Don't know how to open URI: " + this.props.url);
      }
    });
  };
  render() {
    return (
      <TouchableOpacity onPress={this.handleClick}>
        {" "}
        <View style={styles.button}>
          {" "}<Text style={styles.text}>Open {this.props.url}</Text>{" "}
        </View>
        {" "}
      </TouchableOpacity>
    );
  }
}

Here's an example you can try on Expo Snack:

import React, { Component } from 'react';
import { View, StyleSheet, Button, Linking } from 'react-native';
import { Constants } from 'expo';

export default class App extends Component {
  render() {
    return (
      <View style={styles.container}>
       <Button title="Click me" onPress={ ()=>{ Linking.openURL('https://google.com')}} />
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
    paddingTop: Constants.statusBarHeight,
    backgroundColor: '#ecf0f1',
  },
});

Linux Script to check if process is running and act on the result

If you changed awk '{print $1}' to '{ $1=""; print $0}' you will get all processes except for the first as a result. It will start with the field separator (a space generally) but I don't recall killall caring. So:

#! /bin/bash

logfile="/var/oscamlog/oscam1check.log"

case "$(pidof oscam1 | wc -w)" in

0)  echo "oscam1 not running, restarting oscam1:     $(date)" >> $logfile
    /usr/local/bin/oscam1 -b -c /usr/local/etc/oscam1 -t /usr/local/tmp.oscam1 &
    ;;
2)  echo "oscam1 running, all OK:     $(date)" >> $logfile
    ;;
*)  echo "multiple instances of oscam1 running. Stopping & restarting oscam1:     $(date)" >> $logfile
    kill $(pidof oscam1 | awk '{ $1=""; print $0}')
    ;;
esac

It is worth noting that the pidof route seems to work fine for commands that have no spaces, but you would probably want to go back to a ps-based string if you were looking for, say, a python script named myscript that showed up under ps like

root 22415 54.0 0.4 89116 79076 pts/1 S 16:40 0:00 /usr/bin/python /usr/bin/myscript

Just an FYI

Laravel 5.4 ‘cross-env’ Is Not Recognized as an Internal or External Command

There is the same problem in Linux OS. The issue is related on Windows OS, but Homestead is a Ubuntu VM, and the solution posted works strongly good in others SO. I applied the commands sugested by flik, and the problems was solved. I only used the following commands

I only used the following commands

rm -rf node_modules
npm cache clear --force

After

npm install cross-env
npm install 
npm run watch

It's working fine on linux Fedora 25.

how to run mysql in ubuntu through terminal

You seem to just have begun using mysql.

Simple answer: for now use

mysql -u root -p password

Password is usually root by default. You may use other usernames if you have created other user using create user in mysql. For details use "help, help manage accounts, help create users" etc. If you dont want your password to be shown in open just press return key after "-p" and you will be prompted for password next. Hope this resolves the issue.

Fixed height and width for bootstrap carousel

Because some images could have less than 500px of height, it's better to keep the auto-adjust, so i recommend the following:

<div class="carousel-inner" role="listbox" style="max-width:900px; max-height:600px !important;">`

How to delete mysql database through shell command

Another suitable way:

$ mysql -u you -p
<enter password>

>>> DROP DATABASE foo;

When you use 'badidea' or 'thisisunsafe' to bypass a Chrome certificate/HSTS error, does it only apply for the current site?

The SSL errors are often thrown by network management software such as Cyberroam.

To answer your question,

you will have to enter badidea into Chrome every time you visit a website.

You might at times have to enter it more than once, as the site may try to pull in various resources before load, hence causing multiple SSL errors

What's the difference between JPA and Hibernate?

While JPA is the specification, Hibernate is the implementation provider that follows the rules dictated in the specification.

AngularJS - Trigger when radio button is selected

In newer versions of angular (I'm using 1.3) you can basically set the model and the value and the double binding do all the work this example works like a charm:

_x000D_
_x000D_
angular.module('radioExample', []).controller('ExampleController', ['$scope', function($scope) {_x000D_
  $scope.color = {_x000D_
    name: 'blue'_x000D_
  };_x000D_
}]);
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.15/angular.min.js"></script>_x000D_
<html>_x000D_
<body ng-app="radioExample">_x000D_
<form name="myForm" ng-controller="ExampleController">_x000D_
  <input type="radio" ng-model="color.name" value="red">  Red <br/>_x000D_
  <input type="radio" ng-model="color.name" value="green"> Green <br/>_x000D_
  <input type="radio" ng-model="color.name" value="blue"> Blue <br/>_x000D_
  <tt>color = {{color.name}}</tt><br/>_x000D_
 </form>_x000D_
  </body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

What is the purpose of meshgrid in Python / NumPy?

Actually the purpose of np.meshgrid is already mentioned in the documentation:

np.meshgrid

Return coordinate matrices from coordinate vectors.

Make N-D coordinate arrays for vectorized evaluations of N-D scalar/vector fields over N-D grids, given one-dimensional coordinate arrays x1, x2,..., xn.

So it's primary purpose is to create a coordinates matrices.

You probably just asked yourself:

Why do we need to create coordinate matrices?

The reason you need coordinate matrices with Python/NumPy is that there is no direct relation from coordinates to values, except when your coordinates start with zero and are purely positive integers. Then you can just use the indices of an array as the index. However when that's not the case you somehow need to store coordinates alongside your data. That's where grids come in.

Suppose your data is:

1  2  1
2  5  2
1  2  1

However, each value represents a 3 x 2 kilometer area (horizontal x vertical). Suppose your origin is the upper left corner and you want arrays that represent the distance you could use:

import numpy as np
h, v = np.meshgrid(np.arange(3)*3, np.arange(3)*2)

where v is:

array([[0, 0, 0],
       [2, 2, 2],
       [4, 4, 4]])

and h:

array([[0, 3, 6],
       [0, 3, 6],
       [0, 3, 6]])

So if you have two indices, let's say x and y (that's why the return value of meshgrid is usually xx or xs instead of x in this case I chose h for horizontally!) then you can get the x coordinate of the point, the y coordinate of the point and the value at that point by using:

h[x, y]    # horizontal coordinate
v[x, y]    # vertical coordinate
data[x, y]  # value

That makes it much easier to keep track of coordinates and (even more importantly) you can pass them to functions that need to know the coordinates.

A slightly longer explanation

However, np.meshgrid itself isn't often used directly, mostly one just uses one of similar objects np.mgrid or np.ogrid. Here np.mgrid represents the sparse=False and np.ogrid the sparse=True case (I refer to the sparse argument of np.meshgrid). Note that there is a significant difference between np.meshgrid and np.ogrid and np.mgrid: The first two returned values (if there are two or more) are reversed. Often this doesn't matter but you should give meaningful variable names depending on the context.

For example, in case of a 2D grid and matplotlib.pyplot.imshow it makes sense to name the first returned item of np.meshgrid x and the second one y while it's the other way around for np.mgrid and np.ogrid.

np.ogrid and sparse grids

>>> import numpy as np
>>> yy, xx = np.ogrid[-5:6, -5:6]
>>> xx
array([[-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5]])
>>> yy
array([[-5],
       [-4],
       [-3],
       [-2],
       [-1],
       [ 0],
       [ 1],
       [ 2],
       [ 3],
       [ 4],
       [ 5]])
       

As already said the output is reversed when compared to np.meshgrid, that's why I unpacked it as yy, xx instead of xx, yy:

>>> xx, yy = np.meshgrid(np.arange(-5, 6), np.arange(-5, 6), sparse=True)
>>> xx
array([[-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5]])
>>> yy
array([[-5],
       [-4],
       [-3],
       [-2],
       [-1],
       [ 0],
       [ 1],
       [ 2],
       [ 3],
       [ 4],
       [ 5]])

This already looks like coordinates, specifically the x and y lines for 2D plots.

Visualized:

yy, xx = np.ogrid[-5:6, -5:6]
plt.figure()
plt.title('ogrid (sparse meshgrid)')
plt.grid()
plt.xticks(xx.ravel())
plt.yticks(yy.ravel())
plt.scatter(xx, np.zeros_like(xx), color="blue", marker="*")
plt.scatter(np.zeros_like(yy), yy, color="red", marker="x")

enter image description here

np.mgrid and dense/fleshed out grids

>>> yy, xx = np.mgrid[-5:6, -5:6]
>>> xx
array([[-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5]])
>>> yy
array([[-5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5],
       [-4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4],
       [-3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3],
       [-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2],
       [-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1],
       [ 0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0],
       [ 1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1],
       [ 2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2],
       [ 3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3],
       [ 4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4],
       [ 5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5]])
       

The same applies here: The output is reversed compared to np.meshgrid:

>>> xx, yy = np.meshgrid(np.arange(-5, 6), np.arange(-5, 6))
>>> xx
array([[-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5],
       [-5, -4, -3, -2, -1,  0,  1,  2,  3,  4,  5]])
>>> yy
array([[-5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5],
       [-4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4],
       [-3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3],
       [-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2],
       [-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1],
       [ 0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0],
       [ 1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1],
       [ 2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2],
       [ 3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3],
       [ 4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4],
       [ 5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5]])
       

Unlike ogrid these arrays contain all xx and yy coordinates in the -5 <= xx <= 5; -5 <= yy <= 5 grid.

yy, xx = np.mgrid[-5:6, -5:6]
plt.figure()
plt.title('mgrid (dense meshgrid)')
plt.grid()
plt.xticks(xx[0])
plt.yticks(yy[:, 0])
plt.scatter(xx, yy, color="red", marker="x")

enter image description here

Functionality

It's not only limited to 2D, these functions work for arbitrary dimensions (well, there is a maximum number of arguments given to function in Python and a maximum number of dimensions that NumPy allows):

>>> x1, x2, x3, x4 = np.ogrid[:3, 1:4, 2:5, 3:6]
>>> for i, x in enumerate([x1, x2, x3, x4]):
...     print('x{}'.format(i+1))
...     print(repr(x))
x1
array([[[[0]]],


       [[[1]]],


       [[[2]]]])
x2
array([[[[1]],

        [[2]],

        [[3]]]])
x3
array([[[[2],
         [3],
         [4]]]])
x4
array([[[[3, 4, 5]]]])

>>> # equivalent meshgrid output, note how the first two arguments are reversed and the unpacking
>>> x2, x1, x3, x4 = np.meshgrid(np.arange(1,4), np.arange(3), np.arange(2, 5), np.arange(3, 6), sparse=True)
>>> for i, x in enumerate([x1, x2, x3, x4]):
...     print('x{}'.format(i+1))
...     print(repr(x))
# Identical output so it's omitted here.

Even if these also work for 1D there are two (much more common) 1D grid creation functions:

Besides the start and stop argument it also supports the step argument (even complex steps that represent the number of steps):

>>> x1, x2 = np.mgrid[1:10:2, 1:10:4j]
>>> x1  # The dimension with the explicit step width of 2
array([[1., 1., 1., 1.],
       [3., 3., 3., 3.],
       [5., 5., 5., 5.],
       [7., 7., 7., 7.],
       [9., 9., 9., 9.]])
>>> x2  # The dimension with the "number of steps"
array([[ 1.,  4.,  7., 10.],
       [ 1.,  4.,  7., 10.],
       [ 1.,  4.,  7., 10.],
       [ 1.,  4.,  7., 10.],
       [ 1.,  4.,  7., 10.]])
       

Applications

You specifically asked about the purpose and in fact, these grids are extremely useful if you need a coordinate system.

For example if you have a NumPy function that calculates the distance in two dimensions:

def distance_2d(x_point, y_point, x, y):
    return np.hypot(x-x_point, y-y_point)
    

And you want to know the distance of each point:

>>> ys, xs = np.ogrid[-5:5, -5:5]
>>> distances = distance_2d(1, 2, xs, ys)  # distance to point (1, 2)
>>> distances
array([[9.21954446, 8.60232527, 8.06225775, 7.61577311, 7.28010989,
        7.07106781, 7.        , 7.07106781, 7.28010989, 7.61577311],
       [8.48528137, 7.81024968, 7.21110255, 6.70820393, 6.32455532,
        6.08276253, 6.        , 6.08276253, 6.32455532, 6.70820393],
       [7.81024968, 7.07106781, 6.40312424, 5.83095189, 5.38516481,
        5.09901951, 5.        , 5.09901951, 5.38516481, 5.83095189],
       [7.21110255, 6.40312424, 5.65685425, 5.        , 4.47213595,
        4.12310563, 4.        , 4.12310563, 4.47213595, 5.        ],
       [6.70820393, 5.83095189, 5.        , 4.24264069, 3.60555128,
        3.16227766, 3.        , 3.16227766, 3.60555128, 4.24264069],
       [6.32455532, 5.38516481, 4.47213595, 3.60555128, 2.82842712,
        2.23606798, 2.        , 2.23606798, 2.82842712, 3.60555128],
       [6.08276253, 5.09901951, 4.12310563, 3.16227766, 2.23606798,
        1.41421356, 1.        , 1.41421356, 2.23606798, 3.16227766],
       [6.        , 5.        , 4.        , 3.        , 2.        ,
        1.        , 0.        , 1.        , 2.        , 3.        ],
       [6.08276253, 5.09901951, 4.12310563, 3.16227766, 2.23606798,
        1.41421356, 1.        , 1.41421356, 2.23606798, 3.16227766],
       [6.32455532, 5.38516481, 4.47213595, 3.60555128, 2.82842712,
        2.23606798, 2.        , 2.23606798, 2.82842712, 3.60555128]])
        

The output would be identical if one passed in a dense grid instead of an open grid. NumPys broadcasting makes it possible!

Let's visualize the result:

plt.figure()
plt.title('distance to point (1, 2)')
plt.imshow(distances, origin='lower', interpolation="none")
plt.xticks(np.arange(xs.shape[1]), xs.ravel())  # need to set the ticks manually
plt.yticks(np.arange(ys.shape[0]), ys.ravel())
plt.colorbar()

enter image description here

And this is also when NumPys mgrid and ogrid become very convenient because it allows you to easily change the resolution of your grids:

ys, xs = np.ogrid[-5:5:200j, -5:5:200j]
# otherwise same code as above

enter image description here

However, since imshow doesn't support x and y inputs one has to change the ticks by hand. It would be really convenient if it would accept the x and y coordinates, right?

It's easy to write functions with NumPy that deal naturally with grids. Furthermore, there are several functions in NumPy, SciPy, matplotlib that expect you to pass in the grid.

I like images so let's explore matplotlib.pyplot.contour:

ys, xs = np.mgrid[-5:5:200j, -5:5:200j]
density = np.sin(ys)-np.cos(xs)
plt.figure()
plt.contour(xs, ys, density)

enter image description here

Note how the coordinates are already correctly set! That wouldn't be the case if you just passed in the density.

Or to give another fun example using astropy models (this time I don't care much about the coordinates, I just use them to create some grid):

from astropy.modeling import models
z = np.zeros((100, 100))
y, x = np.mgrid[0:100, 0:100]
for _ in range(10):
    g2d = models.Gaussian2D(amplitude=100, 
                           x_mean=np.random.randint(0, 100), 
                           y_mean=np.random.randint(0, 100), 
                           x_stddev=3, 
                           y_stddev=3)
    z += g2d(x, y)
    a2d = models.AiryDisk2D(amplitude=70, 
                            x_0=np.random.randint(0, 100), 
                            y_0=np.random.randint(0, 100), 
                            radius=5)
    z += a2d(x, y)
    

enter image description here

Although that's just "for the looks" several functions related to functional models and fitting (for example scipy.interpolate.interp2d, scipy.interpolate.griddata even show examples using np.mgrid) in Scipy, etc. require grids. Most of these work with open grids and dense grids, however some only work with one of them.

How to check if click event is already bound - JQuery

The best way I see is to use live() or delegate() to capture the event in a parent and not in each child element.

If your button is inside a #parent element, you can replace:

$('#myButton').bind('click', onButtonClicked);

by

$('#parent').delegate('#myButton', 'click', onButtonClicked);

even if #myButton doesn't exist yet when this code is executed.

Removing viewcontrollers from navigation stack

Swift 5.1, Xcode 11

extension UINavigationController{
public func removePreviousController(total: Int){
    let totalViewControllers = self.viewControllers.count
    self.viewControllers.removeSubrange(totalViewControllers-total..<totalViewControllers - 1)
}}

Make sure to call this utility function after viewDidDisappear() of previous controller or viewDidAppear() of new controller

How to select data of a table from another database in SQL Server?

Try using OPENDATASOURCE The syntax is like this:

select * from OPENDATASOURCE ('SQLNCLI', 'Data Source=192.168.6.69;Initial Catalog=AnotherDatabase;Persist Security Info=True;User ID=sa;Password=AnotherDBPassword;MultipleActiveResultSets=true;' ).HumanResources.Department.MyTable    

Send email with PHPMailer - embed image in body

According to PHPMailer Manual, full answer would be :

$mail->AddEmbeddedImage(filename, cid, name);
//Example
$mail->AddEmbeddedImage('my-photo.jpg', 'my-photo', 'my-photo.jpg '); 

Use Case :

$mail->AddEmbeddedImage("rocks.png", "my-attach", "rocks.png");
$mail->Body = 'Embedded Image: <img alt="PHPMailer" src="cid:my-attach"> Here is an image!';

If you want to display an image with a remote URL :

$mail->addStringAttachment(file_get_contents("url"), "filename");

How to filter a RecyclerView with a SearchView

With Android Architecture Components through the use of LiveData this can be easily implemented with any type of Adapter. You simply have to do the following steps:

1. Setup your data to return from the Room Database as LiveData as in the example below:

@Dao
public interface CustomDAO{

@Query("SELECT * FROM words_table WHERE column LIKE :searchquery")
    public LiveData<List<Word>> searchFor(String searchquery);
}

2. Create a ViewModel object to update your data live through a method that will connect your DAO and your UI

public class CustomViewModel extends AndroidViewModel {

    private final AppDatabase mAppDatabase;

    public WordListViewModel(@NonNull Application application) {
        super(application);
        this.mAppDatabase = AppDatabase.getInstance(application.getApplicationContext());
    }

    public LiveData<List<Word>> searchQuery(String query) {
        return mAppDatabase.mWordDAO().searchFor(query);
    }

}

3. Call your data from the ViewModel on the fly by passing in the query through onQueryTextListener as below:

Inside onCreateOptionsMenu set your listener as follows

searchView.setOnQueryTextListener(onQueryTextListener);

Setup your query listener somewhere in your SearchActivity class as follows

private android.support.v7.widget.SearchView.OnQueryTextListener onQueryTextListener =
            new android.support.v7.widget.SearchView.OnQueryTextListener() {
                @Override
                public boolean onQueryTextSubmit(String query) {
                    getResults(query);
                    return true;
                }

                @Override
                public boolean onQueryTextChange(String newText) {
                    getResults(newText);
                    return true;
                }

                private void getResults(String newText) {
                    String queryText = "%" + newText + "%";
                    mCustomViewModel.searchQuery(queryText).observe(
                            SearchResultsActivity.this, new Observer<List<Word>>() {
                                @Override
                                public void onChanged(@Nullable List<Word> words) {
                                    if (words == null) return;
                                    searchAdapter.submitList(words);
                                }
                            });
                }
            };

Note: Steps (1.) and (2.) are standard AAC ViewModel and DAO implementation, the only real "magic" going on here is in the OnQueryTextListener which will update the results of your list dynamically as the query text changes.

If you need more clarification on the matter please don't hesitate to ask. I hope this helped :).

How do I wrap text in a span?

Try putting your text in another div inside your span:

i.e.

<span><div>some text</div></span>

.trim() in JavaScript not working in IE

I had a similar issue when trying to trim a value from an input and then ask if it was equal to nothing:

if ($(this).val().trim() == "")

However this threw a spanner in the works for IE6 - 8. Annoyingly enough I'd tried to var it up like so:

   var originalValue = $(this).val();

However, using jQuery's trim method, works perfectly for me in all browsers..

var originalValueTrimmed = $.trim($(this).val());              
            if (originalValueTrimmed  == "") { ... }

How do I make a Docker container start automatically on system boot?

The default restart policy is no.

For the created containers use docker update to update restart policy.

docker update --restart=always 0576df221c0b

0576df221c0b is the container id.

Installing mcrypt extension for PHP on OSX Mountain Lion

Another possibility for those who want to keep OS X as clean as possible, is to use vagrant [1] to define a php development environment. Vagrant can use VirtualBox [2] in headless mode (~3% of CPU on my 13-inch, Mid 2009 MacBook Pro) to run a virtual machine with the webserver and php and all.

To easily create the vagrant environment you can use this great tool https://puphpet.com/

  1. http://www.vagrantup.com/
  2. https://www.virtualbox.org/

How to print exact sql query in zend framework ?

Select objects have a __toString() method in Zend Framework.

From the Zend Framework manual:

$select = $db->select()
             ->from('products');

$sql = $select->__toString();
echo "$sql\n";

// The output is the string:
//   SELECT * FROM "products"

An alternative solution would be to use the Zend_Db_Profiler. i.e.

$db->getProfiler()->setEnabled(true);

// your code
$this->update($up_value,'customer_id ='.$userid.' and address_id <> '.$data['address_Id']); 

Zend_Debug::dump($db->getProfiler()->getLastQueryProfile()->getQuery());
Zend_Debug::dump($db->getProfiler()->getLastQueryProfile()->getQueryParams());
$db->getProfiler()->setEnabled(false);

http://framework.zend.com/manual/en/zend.db.select.html

Swift: Reload a View Controller

This might be a little late, but did you try calling loadView()?

In C - check if a char exists in a char array

You want

strchr (const char *s, int c)

If the character c is in the string s it returns a pointer to the location in s. Otherwise it returns NULL. So just use your list of invalid characters as the string.

How do I get my Python program to sleep for 50 milliseconds?

Use time.sleep():

import time
time.sleep(50 / 1000)

See the Python documentation: https://docs.python.org/library/time.html#time.sleep

How to get the innerHTML of selectable jquery element?

The parameter ui has a property called selected which is a reference to the selected dom element, you can call innerHTML on that element.

Your code $('.ui-selected').innerHTML tries to return the innerHTML property of a jQuery wrapper element for a dom element with class ui-selected

$(function () {
    $("#select-image").selectable({
        selected: function (event, ui) {
            var $variable = ui.selected.innerHTML; // or $(ui.selected).html()
            console.log($variable);
        }
    });
});

Demo: Fiddle

How do I hide the status bar in a Swift iOS app?

I actually figured this out myself. I'll add my solution as another option.

extension UIViewController {
    func prefersStatusBarHidden() -> Bool {
        return true
    }
}

How do I format a date in Jinja2?

You can use it like this in jinja template {{ row.session_start_date_time.strftime('%d-%m-%Y %H:%M:%S')}}

In this code the field name is row.session_start_date_time.

Remove json element

var json = { ... };
var key = "foo";
delete json[key]; // Removes json.foo from the dictionary.

You can use splice to remove elements from an array.

iPhone UIView Animation Best Practice

I have been using the latter for a lot of nice lightweight animations. You can use it crossfade two views, or fade one in in front of another, or fade it out. You can shoot a view over another like a banner, you can make a view stretch or shrink... I'm getting a lot of mileage out of beginAnimation/commitAnimations.

Don't think that all you can do is:

[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:myview cache:YES];

Here is a sample:

[UIView beginAnimations:nil context:NULL]; {
    [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
    [UIView setAnimationDuration:1.0];
    [UIView setAnimationDelegate:self];
    if (movingViewIn) {
// after the animation is over, call afterAnimationProceedWithGame
//  to start the game
        [UIView setAnimationDidStopSelector:@selector(afterAnimationProceedWithGame)];

//      [UIView setAnimationRepeatCount:5.0]; // don't forget you can repeat an animation
//      [UIView setAnimationDelay:0.50];
//      [UIView setAnimationRepeatAutoreverses:YES];

        gameView.alpha = 1.0;
        topGameView.alpha = 1.0;
        viewrect1.origin.y = selfrect.size.height - (viewrect1.size.height);
        viewrect2.origin.y = -20;

        topGameView.alpha = 1.0;
    }
    else {
    // call putBackStatusBar after animation to restore the state after this animation
        [UIView setAnimationDidStopSelector:@selector(putBackStatusBar)];
        gameView.alpha = 0.0;
        topGameView.alpha = 0.0;
    }
    [gameView setFrame:viewrect1];
    [topGameView setFrame:viewrect2];

} [UIView commitAnimations];

As you can see, you can play with alpha, frames, and even sizes of a view. Play around. You may be surprised with its capabilities.

How can I flush GPU memory using CUDA (physical reset is unavailable)

for the ones using python:

import torch, gc
gc.collect()
torch.cuda.empty_cache()

string comparison in batch file

Just put quotes around the Environment variable (as you have done) :
if "%DevEnvDir%" == "C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\"
but it's the way you put opening bracket without a space that is confusing it.

Works for me...

C:\if "%gtk_basepath%" == "C:\Program Files\GtkSharp\2.12\" (echo yes)
yes

Could not open input file: composer.phar

Initially, I was running php composer.phar self-update and got the same error message.

As a resolve, you should use composer command directly after install it.From the command prompt, just type composer and press enter.

If composer is installed correctly then you should able to see a lot of suggestion and command list from composer.

If you are up to this point then you should able to run composer self-update directly.

How can I find out what FOREIGN KEY constraint references a table in SQL Server?

The easiest way to get Primary Key and Foreign Key for a table is:

/*  Get primary key and foreign key for a table */
USE DatabaseName;

SELECT CONSTRAINT_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE CONSTRAINT_NAME LIKE 'PK%' AND
TABLE_NAME = 'TableName'

SELECT CONSTRAINT_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE CONSTRAINT_NAME LIKE 'FK%' AND
TABLE_NAME = 'TableName'

Reset textbox value in javascript

To set value

 $('#searchField').val('your_value');

to retrieve value

$('#searchField').val();

Xcode 5.1 - No architectures to compile for (ONLY_ACTIVE_ARCH=YES, active arch=x86_64, VALID_ARCHS=i386)

Add: Architectures: $(ARCHS_STANDARD_INCLUDING_64_BIT)

Valid architectures: arm64 armv7 armv7s

How to normalize a signal to zero mean and unit variance?

if your signal is in the matrix X, you make it zero-mean by removing the average:

X=X-mean(X(:));

and unit variance by dividing by the standard deviation:

X=X/std(X(:));

C - casting int to char and append char to char

int i = 100;
char c = (char)i;

There is no way to append one char to another. But you can create an array of chars and use it.

Create <div> and append <div> dynamically

var iDiv = document.createElement('div'),
    jDiv = document.createElement('div');
iDiv.id = 'block';
iDiv.className = 'block';
jDiv.className = 'block-2';
iDiv.appendChild(jDiv);
document.getElementsByTagName('body')[0].appendChild(iDiv);

Returning an empty array

A different way to return an empty array is to use a constant as all empty arrays of a given type are the same.

private static final File[] NO_FILES = {};
private static File[] bar(){
    return NO_FILES;
}

What causes: "Notice: Uninitialized string offset" to appear?

It means one of your arrays isn't actually an array.

By the way, your if check is unnecessary. If $varsCount is 0 the for loop won't execute anyway.

C# Test if user has write access to a folder

Here is a modified version of CsabaS's answer, which accounts for explicit deny access rules. The function goes through all FileSystemAccessRules for a directory, and checks if the current user is in a role which has access to a directory. If no such roles are found or the user is in a role with denied access, the function returns false. To check read rights, pass FileSystemRights.Read to the function; for write rights, pass FileSystemRights.Write. If you want to check an arbitrary user's rights and not the current one's, substitute the currentUser WindowsIdentity for the desired WindowsIdentity. I would also advise against relying on functions like this to determine if the user can safely use the directory. This answer perfectly explains why.

    public static bool UserHasDirectoryAccessRights(string path, FileSystemRights accessRights)
    {
        var isInRoleWithAccess = false;

        try
        {
            var di = new DirectoryInfo(path);
            var acl = di.GetAccessControl();
            var rules = acl.GetAccessRules(true, true, typeof(NTAccount));

            var currentUser = WindowsIdentity.GetCurrent();
            var principal = new WindowsPrincipal(currentUser);
            foreach (AuthorizationRule rule in rules)
            {
                var fsAccessRule = rule as FileSystemAccessRule;
                if (fsAccessRule == null)
                    continue;

                if ((fsAccessRule.FileSystemRights & accessRights) > 0)
                {
                    var ntAccount = rule.IdentityReference as NTAccount;
                    if (ntAccount == null)
                        continue;

                    if (principal.IsInRole(ntAccount.Value))
                    {
                        if (fsAccessRule.AccessControlType == AccessControlType.Deny)
                            return false;
                        isInRoleWithAccess = true;
                    }
                }
            }
        }
        catch (UnauthorizedAccessException)
        {
            return false;
        }
        return isInRoleWithAccess;
    }

XAMPP, Apache - Error: Apache shutdown unexpectedly

As I am working in a corporate environment where developers faces firewall issues, none of the other answers resolved my issue.

As the port is not used by Skype, but by some other internal applications, I followed the below steps to resolve the issue:

Step 1 - From the XAMPP Control Panel, under Apache, click the Config button, and select the Apache (httpd.conf).

Inside the httpd.conf file, somehow I found a line that says:

Listen 80

And change the 80 into any number / port you want. In my scenario I’m using port 8080.

Listen 8080

Still from the httpd.conf file, I found another line that says:

ServerName localhost:80

Change 80 to 8080.

ServerName localhost:8080

Step 2 - From the XAMPP Control Panel, under Apache, click the Config button again, but this time select the Apache (httpd-ssl.conf). Inside the httpd-ssl.conf file, find line that says

Listen 443

And change the 443 into any number / port you want. I’ll using 4433 as the new port number.

Listen 4433

Still from the httpd-ssl.conf file, find another line that says

<VirtualHost _default_:443>

ServerName localhost:443

And change 443 to 4433.

<VirtualHost _default_:4433>

ServerName localhost:4433

Remember to save the httpd.conf and httpd-ssl.conf files after performing some changes. Then restart the Apache service.

php foreach with multidimensional array

This would have been a comment under Brad's answer, but I don't have a high enough reputation.

Recently I found that I needed the key of the multidimensional array too, i.e., it wasn't just an index for the array, in the foreach loop.

In order to achieve that, you could use something very similar to the accepted answer, but instead split the key and value as follows

foreach ($mda as $mdaKey => $mdaData) {
    echo $mdaKey . ": " . $mdaData["value"];
}

Hope that helps someone.

In Java, what is the best way to determine the size of an object?

This answer is not related to Object size, but when you are using array to accommodate the objects; how much memory size it will allocate for the object.

So arrays, list, or map all those collection won't be going to store objects really (only at the time of primitives, real object memory size is needed), it will store only references for those objects.

Now the Used heap memory = sizeOfObj + sizeOfRef (* 4 bytes) in collection

  • (4/8 bytes) depends on (32/64 bit) OS

PRIMITIVES

int   [] intArray    = new int   [1]; will require 4 bytes.
long  [] longArray   = new long  [1]; will require 8 bytes.

OBJECTS

Object[] objectArray = new Object[1]; will require 4 bytes. The object can be any user defined Object.
Long  [] longArray   = new Long  [1]; will require 4 bytes.

I mean to say all the object REFERENCE needs only 4 bytes of memory. It may be String reference OR Double object reference, But depends on object creation the memory needed will vary.

e.g) If i create object for the below class ReferenceMemoryTest then 4 + 4 + 4 = 12 bytes of memory will be created. The memory may differ when you are trying to initialize the references.

 class ReferenceMemoryTest {
    public String refStr;
    public Object refObj;
    public Double refDoub; 
}

So when are creating object/reference array, all its contents will be occupied with NULL references. And we know each reference requires 4 bytes.

And finally, memory allocation for the below code is 20 bytes.

ReferenceMemoryTest ref1 = new ReferenceMemoryTest(); ( 4(ref1) + 12 = 16 bytes) ReferenceMemoryTest ref2 = ref1; ( 4(ref2) + 16 = 20 bytes)

Using parameters in batch files at Windows command line

Using parameters in batch files: %0 and %9

Batch files can refer to the words passed in as parameters with the tokens: %0 to %9.

%0 is the program name as it was called.
%1 is the first command line parameter
%2 is the second command line parameter
and so on till %9.

parameters passed in on the commandline must be alphanumeric characters and delimited by spaces. Since %0 is the program name as it was called, in DOS %0 will be empty for AUTOEXEC.BAT if started at boot time.

Example:

Put the following command in a batch file called mybatch.bat:

@echo off
@echo hello %1 %2
pause

Invoking the batch file like this: mybatch john billy would output:

hello john billy

Get more than 9 parameters for a batch file, use: %*

The Percent Star token %* means "the rest of the parameters". You can use a for loop to grab them, as defined here:

http://www.robvanderwoude.com/parameters.php

Notes about delimiters for batch parameters

Some characters in the command line parameters are ignored by batch files, depending on the DOS version, whether they are "escaped" or not, and often depending on their location in the command line:

commas (",") are replaced by spaces, unless they are part of a string in 
double quotes

semicolons (";") are replaced by spaces, unless they are part of a string in 
double quotes

"=" characters are sometimes replaced by spaces, not if they are part of a 
string in double quotes

the first forward slash ("/") is replaced by a space only if it immediately 
follows the command, without a leading space

multiple spaces are replaced by a single space, unless they are part of a 
string in double quotes

tabs are replaced by a single space

leading spaces before the first command line argument are ignored

How to get milliseconds from LocalDateTime in Java 8

To avoid ZoneId you can do:

LocalDateTime date = LocalDateTime.of(1970, 1, 1, 0, 0);

System.out.println("Initial Epoch (TimeInMillis): " + date.toInstant(ZoneOffset.ofTotalSeconds(0)).toEpochMilli());

Getting 0 as value, that's right!

Setting up a JavaScript variable from Spring model by using Thymeleaf

MAKE sure you have thymleaf on page already

//Use this in java
@Controller
@RequestMapping("/showingTymleafTextInJavaScript")
public String thankYou(Model model){
 model.addAttribute("showTextFromJavaController","dummy text");
 return "showingTymleafTextInJavaScript";
}


//thymleaf page  javascript page
<script>
var showtext = "[[${showTextFromJavaController}]]";
console.log(showtext);
</script>

How to detect when an @Input() value changes in Angular?

Here ngOnChanges will trigger always when your input property changes:

ngOnChanges(changes: SimpleChanges): void {
 console.log(changes.categoryId.currentValue)
}

Excel 2010 VBA - Close file No Save without prompt

If you're not wanting to save changes set savechanges to false

    Sub CloseBook2()
        ActiveWorkbook.Close savechanges:=False
    End Sub

for more examples, http://support.microsoft.com/kb/213428 and i believe in the past I've just used

    ActiveWorkbook.Close False

What's the easiest way to call a function every 5 seconds in jQuery?

Just a little tip for the first answer. If your function is already defined, reference the function but don't call it!!! So don't put any parentheses after the function name. Just like:

my_function(){};
setInterval(my_function,10000);

JavaScript: Alert.Show(message) From ASP.NET Code-behind

if you are using ScriptManager on the page then you can also try using this:

System.Web.UI.ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "AlertBox", "alert('Your Message');", true);

How to reduce the space between <p> tags?

<style type="text/css">
 p {margin-bottom: -1em;  margin-top: 0em;} 
</style>

This completely worked for me. Paragraphs were right below each other. When I used 0em for both the margins, there was still some space left in between the lines. I went for Developer tools in my browser, tried with -1em and it worked.

Accessing an SQLite Database in Swift

Sometimes, a Swift version of the "SQLite in 5 minutes or less" approach shown on sqlite.org is sufficient. The "5 minutes or less" approach uses sqlite3_exec() which is a convenience wrapper for sqlite3_prepare(), sqlite3_step(), sqlite3_column(), and sqlite3_finalize().

Swift 2.2 can directly support the sqlite3_exec() callback function pointer as either a global, non-instance procedure func or a non-capturing literal closure {}.

Readable typealias

typealias sqlite3 = COpaquePointer
typealias CCharHandle = UnsafeMutablePointer<UnsafeMutablePointer<CChar>>
typealias CCharPointer = UnsafeMutablePointer<CChar>
typealias CVoidPointer = UnsafeMutablePointer<Void>

Callback Approach

func callback(
    resultVoidPointer: CVoidPointer, // void *NotUsed 
    columnCount: CInt,               // int argc
    values: CCharHandle,             // char **argv     
    columns: CCharHandle             // char **azColName
    ) -> CInt {
    for  i in 0 ..< Int(columnCount) {
        guard let value = String.fromCString(values[i]) 
        else { continue }
        guard let column = String.fromCString(columns[i]) 
        else { continue }
        print("\(column) = \(value)")
    }
    return 0 // status ok
}

func sqlQueryCallbackBasic(argc: Int, argv: [String]) -> Int {
    var db: sqlite3 = nil 
    var zErrMsg:CCharPointer = nil
    var rc: Int32 = 0 // result code

    if argc != 3 {
        print(String(format: "ERROR: Usage: %s DATABASE SQL-STATEMENT", argv[0]))
        return 1
    }

    rc = sqlite3_open(argv[1], &db)
    if  rc != 0 {
        print("ERROR: sqlite3_open " + String.fromCString(sqlite3_errmsg(db))! ?? "" )
        sqlite3_close(db)
        return 1
    }

    rc = sqlite3_exec(db, argv[2], callback, nil, &zErrMsg)
    if rc != SQLITE_OK {
        print("ERROR: sqlite3_exec " + String.fromCString(zErrMsg)! ?? "")
        sqlite3_free(zErrMsg)
    }

    sqlite3_close(db)
    return 0
}

Closure Approach

func sqlQueryClosureBasic(argc argc: Int, argv: [String]) -> Int {
    var db: sqlite3 = nil 
    var zErrMsg:CCharPointer = nil
    var rc: Int32 = 0

    if argc != 3 {
        print(String(format: "ERROR: Usage: %s DATABASE SQL-STATEMENT", argv[0]))
        return 1
    }

    rc = sqlite3_open(argv[1], &db)
    if  rc != 0 {
        print("ERROR: sqlite3_open " + String.fromCString(sqlite3_errmsg(db))! ?? "" )
        sqlite3_close(db)
        return 1
    }

    rc = sqlite3_exec(
        db,      // database 
        argv[2], // statement
        {        // callback: non-capturing closure
            resultVoidPointer, columnCount, values, columns in

            for i in 0 ..< Int(columnCount) {
                guard let value = String.fromCString(values[i]) 
                else { continue }
                guard let column = String.fromCString(columns[i]) 
                else { continue }
                print("\(column) = \(value)")
            }
            return 0
        }, 
        nil, 
        &zErrMsg
    )

    if rc != SQLITE_OK {
        let errorMsg = String.fromCString(zErrMsg)! ?? ""
        print("ERROR: sqlite3_exec \(errorMsg)")
        sqlite3_free(zErrMsg)
    }
    sqlite3_close(db)
    return 0
}

To prepare an Xcode project to call a C library such as SQLite, one needs to (1) add a Bridging-Header.h file reference C headers like #import "sqlite3.h", (2) add Bridging-Header.h to Objective-C Bridging Header in project settings, and (3) add libsqlite3.tbd to Link Binary With Library target settings.

The sqlite.org's "SQLite in 5 minutes or less" example is implemented in a Swift Xcode7 project here.

XML shape drawable not rendering desired color

In drawable I use this xml code to define the border and background:

<shape xmlns:android="http://schemas.android.com/apk/res/android"> 
  <stroke android:width="4dp" android:color="#D8FDFB" /> 
  <padding android:left="7dp" android:top="7dp" 
    android:right="7dp" android:bottom="7dp" /> 
  <corners android:radius="4dp" /> 
  <solid android:color="#f0600000"/> 
</shape> 

WCF ServiceHost access rights

Another solution is to use the address

http://localhost:8732/Design_Time_Addresses/YOUR_ADDRESS .

.NET Framework (3.5) automatically register this address (http://*:8732/Design_Time_Addresses) for debugging scope. This is useful when you need to host services inside visual studio for debugging or testing. Don't use this on production...

Determining the last row in a single column

Old thread but I have found a simple way that seems to work

ws.getRange("A2").getNextDataCell(SpreadsheetApp.Direction.DOWN).getLastRow()

Is it possible to insert HTML content in XML document?

Please see this.

Text inside a CDATA section will be ignored by the parser.

http://www.w3schools.com/xml/dom_cdatasection.asp

This is will help you to understand the basics about XML

Does Git Add have a verbose switch

Well, like (almost) every console program for unix-like systems, git does not tell you anything if a command succeeds. It prints out something only if there's something wrong.

However if you want to be sure of what just happened, just type

git status

and see which changes are going to be committed and which not. I suggest you to use this before every commit, just to be sure that you are not forgetting anything.

Since you seem new to git, here is a link to a free online book that introduces you to git. It's very useful, it writes about basics as well as well known different workflows: http://git-scm.com/book

Simple way to create matrix of random numbers

You can drop the range(len()):

weights_h = [[random.random() for e in inputs[0]] for e in range(hiden_neurons)]

But really, you should probably use numpy.

In [9]: numpy.random.random((3, 3))
Out[9]:
array([[ 0.37052381,  0.03463207,  0.10669077],
       [ 0.05862909,  0.8515325 ,  0.79809676],
       [ 0.43203632,  0.54633635,  0.09076408]])

How to set header and options in axios?

Here is the Right way:-

_x000D_
_x000D_
axios.post('url', {"body":data}, {_x000D_
    headers: {_x000D_
    'Content-Type': 'application/json'_x000D_
    }_x000D_
  }_x000D_
)
_x000D_
_x000D_
_x000D_

Best way to initialize (empty) array in PHP

$myArray = []; 

Creates empty array.

You can push values onto the array later, like so:

$myArray[] = "tree";
$myArray[] = "house";
$myArray[] = "dog";

At this point, $myArray contains "tree", "house" and "dog". Each of the above commands appends to the array, preserving the items that were already there.

Having come from other languages, this way of appending to an array seemed strange to me. I expected to have to do something like $myArray += "dog" or something... or maybe an "add()" method like Visual Basic collections have. But this direct append syntax certainly is short and convenient.

You actually have to use the unset() function to remove items:

unset($myArray[1]); 

... would remove "house" from the array (arrays are zero-based).

unset($myArray); 

... would destroy the entire array.

To be clear, the empty square brackets syntax for appending to an array is simply a way of telling PHP to assign the indexes to each value automatically, rather than YOU assigning the indexes. Under the covers, PHP is actually doing this:

$myArray[0] = "tree";
$myArray[1] = "house";
$myArray[2] = "dog";

You can assign indexes yourself if you want, and you can use any numbers you want. You can also assign index numbers to some items and not others. If you do that, PHP will fill in the missing index numbers, incrementing from the largest index number assigned as it goes.

So if you do this:

$myArray[10] = "tree";
$myArray[20] = "house";
$myArray[] = "dog";

... the item "dog" will be given an index number of 21. PHP does not do intelligent pattern matching for incremental index assignment, so it won't know that you might have wanted it to assign an index of 30 to "dog". You can use other functions to specify the increment pattern for an array. I won't go into that here, but its all in the PHP docs.

Cheers,

-=Cameron

How to get named excel sheets while exporting from SSRS

Necromancing, just in case all the links go dark:

  1. Add a group to your report
    Also, be advised to set the sort order of the group expression here, so the tabs will be alphabetically sorted (or however you want it sorted).

    1. Add a group to your report

    • 'Zeilengruppe' means 'Target group'
    • 'Gruppeneigenschaften' means 'Group properties'
  2. Set the page break in the group properties 2. Set the page break in the group properties

    • 'Seitenumbruche' means 'Page break'
    • 'Zwischen den einzelnen Instanzen einer Gruppe' means 'Between the individual instances of a group'
  3. Now you need to set the PageName of the Tablix Member (group), NOT the PageName of the Tablix itselfs.
    If you got the right object, if will say "Tablix Member" (Tablix-Element in German) in the title box of the properties grid. If it's the wrong object, it will say only "table/tablix" (without member) in the property grid's title box.

  4. Note: If you get the tablix instead of the tablix member, it will put the same tab name in every tab, followed by a (tabNum)! If that happens, you now know what the problem is. Tablix Member

MultiTabExcelFile

How to Select Every Row Where Column Value is NOT Distinct

Just for fun, here's another way:

;with counts as (
    select CustomerName, EmailAddress,
      count(*) over (partition by EmailAddress) as num
    from Customers
)
select CustomerName, EmailAddress
from counts
where num > 1

Histogram Matplotlib

If you don't want bars you can plot it like this:

import numpy as np
import matplotlib.pyplot as plt

mu, sigma = 100, 15
x = mu + sigma * np.random.randn(10000)

bins, edges = np.histogram(x, 50, normed=1)
left,right = edges[:-1],edges[1:]
X = np.array([left,right]).T.flatten()
Y = np.array([bins,bins]).T.flatten()

plt.plot(X,Y)
plt.show()

histogram

How to run a C# console application with the console hidden

If you're interested in the output, you can use this function:

private static string ExecCommand(string filename, string arguments)
{
    Process process = new Process();
    ProcessStartInfo psi = new ProcessStartInfo(filename);
    psi.Arguments = arguments;
    psi.CreateNoWindow = true;
    psi.RedirectStandardOutput = true;
    psi.RedirectStandardError = true;
    psi.UseShellExecute = false;
    process.StartInfo = psi;

    StringBuilder output = new StringBuilder();
    process.OutputDataReceived += (sender, e) => { output.AppendLine(e.Data); };
    process.ErrorDataReceived += (sender, e) => { output.AppendLine(e.Data); };

    // run the process
    process.Start();

    // start reading output to events
    process.BeginOutputReadLine();
    process.BeginErrorReadLine();

    // wait for process to exit
    process.WaitForExit();

    if (process.ExitCode != 0)
        throw new Exception("Command " + psi.FileName + " returned exit code " + process.ExitCode);

    return output.ToString();
}

It runs the given command line program, waits for it to finish and returns the output as string.

Why aren't programs written in Assembly more often?

In addition to other people's answers of readability, maintainability, shorter code and therefore fewer bugs, and being much easier, I'll add an additional reason:

program speed.

Yes, in assembly you can hand tune your code to make use of every last cycle and make it as fast as is physically possible. However who has the time? If you write a not-completely-stupid C program, the compiler will do a really good job of optimizing for you. Probably making at least 95% of the optimizations you'd do by hand, without you having to worry about keeping track of any of it. There's definitely a 90/10 kind of rule here, where that last 5% of optimizations will end up taking up 95% of your time. So why bother?

How do I empty an input value with jQuery?

You could try:

$('input.class').removeAttr('value');
$('#inputID').removeAttr('value');

TransactionRequiredException Executing an update/delete query

The same exception occurred to me in a somewhat different situation. Since I've been searching here for an answer, maybe it'll help somebody.

I my case the exception has been happening because I called the (properly annotated) @Transactional method from a SERVICE CONSTRUCTOR... Since my idea was simply to make this method run at the start, I annotated it as following, and stopped calling in a wrong way. Exception is gone, and code is better :)

@EventListener(ContextRefreshedEvent.class)
@Transactional
public void methodName() {...}

@Transactional import: import org.springframework.transaction.annotation.Transactional;

RegEx to match stuff between parentheses

If s is your string:

s.replace(/^[^(]*\(/, "") // trim everything before first parenthesis
 .replace(/\)[^(]*$/, "") // trim everything after last parenthesis
 .split(/\)[^(]*\(/);      // split between parenthesis

Access Database opens as read only

on my pc I had the same problem and it was because in properties -> security I didn't have the ownership of the file...

transparent navigation bar ios

For those looking for OBJC solution, to be added in App Delegate didFinishLaunchingWithOptions method:

[[UINavigationBar appearance] setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
[UINavigationBar appearance].shadowImage = [UIImage new];
[UINavigationBar appearance].backgroundColor = [UIColor clearColor];
[UINavigationBar appearance].translucent = YES;

What are Keycloak's OAuth2 / OpenID Connect endpoints?

In version 1.9.0 json with all endpoints is at address /auth/realms/{realm}

  • Authorization Endpoint: /auth/realms/{realm}/account
  • Token Endpoint: /auth/realms/{realm}/protocol/openid-connect

SQL Query to search schema of all tables

Use this query :

SELECT 
    t.name AS table_name,
    SCHEMA_NAME(schema_id) AS schema_name,
    c.name AS column_name , *
FROM sys.tables AS t
    INNER JOIN sys.columns c ON t.OBJECT_ID = c.OBJECT_ID 
Where 
    ( c.name LIKE '%' + '<ColumnName>' + '%' )
    AND 
    ( t.type = 'U' ) -- Use This To Prevent Selecting System Tables

Android get current Locale, not default

As per official documentation ConfigurationCompat is deprecated in support libraries

You can consider using

LocaleListCompat.getDefault()[0].toLanguageTag() 0th position will be user preferred locale

To get Default locale at 0th position would be LocaleListCompat.getAdjustedDefault()

Reading Excel file using node.js

There are a few different libraries doing parsing of Excel files (.xlsx). I will list two projects I find interesting and worth looking into.

Node-xlsx

Excel parser and builder. It's kind of a wrapper for a popular project JS-XLSX, which is a pure javascript implementation from the Office Open XML spec.

node-xlsx project page

Example for parsing file

var xlsx = require('node-xlsx');

var obj = xlsx.parse(__dirname + '/myFile.xlsx'); // parses a file

var obj = xlsx.parse(fs.readFileSync(__dirname + '/myFile.xlsx')); // parses a buffer

ExcelJS

Read, manipulate and write spreadsheet data and styles to XLSX and JSON. It's an active project. At the time of writing the latest commit was 9 hours ago. I haven't tested this myself, but the api looks extensive with a lot of possibilites.

exceljs project page

Code example:

// read from a file
var workbook = new Excel.Workbook();
workbook.xlsx.readFile(filename)
    .then(function() {
        // use workbook
    });

// pipe from stream
var workbook = new Excel.Workbook();
stream.pipe(workbook.xlsx.createInputStream());

Fatal error: Call to a member function prepare() on null

In ---- model: Add use Jenssegers\Mongodb\Eloquent\Model as Eloquent;

Change the class ----- extends Model to class ----- extends Eloquent

Disable form auto submit on button click

Buttons like <button>Click to do something</button> are submit buttons.

Set type="button" to change that. type="submit" is the default (as specified by the HTML recommendation).

How to correctly iterate through getElementsByClassName

You could always use array methods:

var slides = getElementsByClassName("slide");
Array.prototype.forEach.call(slides, function(slide, index) {
    Distribute(slides.item(index));
});

How do I install SciPy on 64 bit Windows?

I have a 32-bit Python 3.5 on a 64-bit Windows 8.1 machine. I just tried almost every way I can find on Stack Overflow and no one works!

Then on here I found it. It says:

SciPy is software for mathematics, science, and engineering.

Requires numpy+mkl.

Install numpy+mkl before installing scipy.

mkl matters!! But nobody said anything about that before!

Then I installed mkl:

C:\Users\****\Desktop\a> pip install mkl_service-1.1.2-cp35-cp35m-win32.whl
Processing c:\users\****\desktop\a\mkl_service-1.1.2-cp35-cp35m-win32.whl
Installing collected packages: mkl-service
Successfully installed mkl-service-1.1.2

Then I installed SciPy:

C:\Users\****\Desktop\a>pip install scipy-0.18.1-cp35-cp35m-win32.whl
Processing c:\users\****\desktop\a\scipy-0.18.1-cp35-cp35m-win32.whl
Installing collected packages: scipy
Successfully installed scipy-0.18.1

It worked~ yeah :)

A tip: You can just google "whl_file_name.whl" to know where to download it~ :)

Update:

After all these steps you will find that you still can not use SciPy in Python 3. If you print "import scipy" you will find there are error messages, but don't worry, there is only one more thing to do. Here ——just comment out that line, simple and useful.

from numpy._distributor_init import NUMPY_MKL

I promise that it is the last thing to do :)

Enter image description here

PS: Before all these steps, you better install NumPy first. That's very simple using this command:

pip install numpy

How to convert a list into data table

you can use this extension method and call it like this.

DataTable dt =   YourList.ToDataTable();

public static DataTable ToDataTable<T>(this List<T> iList)
        {
            DataTable dataTable = new DataTable();
            PropertyDescriptorCollection propertyDescriptorCollection =
                TypeDescriptor.GetProperties(typeof(T));
            for (int i = 0; i < propertyDescriptorCollection.Count; i++)
            {
                PropertyDescriptor propertyDescriptor = propertyDescriptorCollection[i];
                Type type = propertyDescriptor.PropertyType;

                if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>))
                    type = Nullable.GetUnderlyingType(type);


                dataTable.Columns.Add(propertyDescriptor.Name, type);
            }
            object[] values = new object[propertyDescriptorCollection.Count];
            foreach (T iListItem in iList)
            {
                for (int i = 0; i < values.Length; i++)
                {
                    values[i] = propertyDescriptorCollection[i].GetValue(iListItem);
                }
                dataTable.Rows.Add(values);
            }
            return dataTable;
        }

Reliable way to convert a file to a byte[]

Not to repeat what everyone already have said but keep the following cheat sheet handly for File manipulations:

  1. System.IO.File.ReadAllBytes(filename);
  2. File.Exists(filename)
  3. Path.Combine(folderName, resOfThePath);
  4. Path.GetFullPath(path); // converts a relative path to absolute one
  5. Path.GetExtension(path);

Table row and column number in jQuery

Can you output that data in the cells as you are creating the table?

so your table would look like this:

<table>
  <thead>...</thead>
  <tbody>
    <tr><td data-row='1' data-column='1'>value</td>
      <td data-row='1' data-column='2'>value</td>
      <td data-row='1' data-column='3'>value</td></tr>

  <tbody>
</table>

then it would be a simple matter

$("td").click(function(event) {
   var row = $(this).attr("data-row");
   var col = $(this).attr("data-col");
}

Javascript - Append HTML to container element without innerHTML

This is what DocumentFragment was meant for.

var frag = document.createDocumentFragment();
var span = document.createElement("span");
span.innerHTML = htmldata;
for (var i = 0, ii = span.childNodes.length; i < ii; i++) {
    frag.appendChild(span.childNodes[i]);
}
element.appendChild(frag);

document.createDocumentFragment, .childNodes

Replace words in a string - Ruby

sentence.sub! 'Robert', 'Joe'

Won't cause an exception if the replaced word isn't in the sentence (the []= variant will).

How to replace all instances?

The above replaces only the first instance of "Robert".

To replace all instances use gsub/gsub! (ie. "global substitution"):

sentence.gsub! 'Robert', 'Joe'

The above will replace all instances of Robert with Joe.

Is it possible to append to innerHTML without destroying descendants' event listeners?

Unfortunately, assignment to innerHTML causes the destruction of all child elements, even if you're trying to append. If you want to preserve child nodes (and their event handlers), you'll need to use DOM functions:

function start() {
    var myspan = document.getElementById("myspan");
    myspan.onclick = function() { alert ("hi"); };

    var mydiv = document.getElementById("mydiv");
    mydiv.appendChild(document.createTextNode("bar"));
}

Edit: Bob's solution, from the comments. Post your answer, Bob! Get credit for it. :-)

function start() {
    var myspan = document.getElementById("myspan");
    myspan.onclick = function() { alert ("hi"); };

    var mydiv = document.getElementById("mydiv");
    var newcontent = document.createElement('div');
    newcontent.innerHTML = "bar";

    while (newcontent.firstChild) {
        mydiv.appendChild(newcontent.firstChild);
    }
}

Finding blocking/locking queries in MS SQL (mssql)

Use the script: sp_blocker_pss08 or SQL Trace/Profiler and the Blocked Process Report event class.

Create a Bitmap/Drawable from file path

you can't access your drawables via a path, so if you want a human readable interface with your drawables that you can build programatically.

declare a HashMap somewhere in your class:

private static HashMap<String, Integer> images = null;

//Then initialize it in your constructor:

public myClass() {
  if (images == null) {
    images = new HashMap<String, Integer>();
    images.put("Human1Arm", R.drawable.human_one_arm);
    // for all your images - don't worry, this is really fast and will only happen once
  }
}

Now for access -

String drawable = "wrench";
// fill in this value however you want, but in the end you want Human1Arm etc
// access is fast and easy:
Bitmap wrench = BitmapFactory.decodeResource(getResources(), images.get(drawable));
canvas.drawColor(Color .BLACK);
Log.d("OLOLOLO",Integer.toString(wrench.getHeight()));
canvas.drawBitmap(wrench, left, top, null);

Fixing Segmentation faults in C++

Yes, there is a problem with pointers. Very likely you're using one that's not initialized properly, but it's also possible that you're messing up your memory management with double frees or some such.

To avoid uninitialized pointers as local variables, try declaring them as late as possible, preferably (and this isn't always possible) when they can be initialized with a meaningful value. Convince yourself that they will have a value before they're being used, by examining the code. If you have difficulty with that, initialize them to a null pointer constant (usually written as NULL or 0) and check them.

To avoid uninitialized pointers as member values, make sure they're initialized properly in the constructor, and handled properly in copy constructors and assignment operators. Don't rely on an init function for memory management, although you can for other initialization.

If your class doesn't need copy constructors or assignment operators, you can declare them as private member functions and never define them. That will cause a compiler error if they're explicitly or implicitly used.

Use smart pointers when applicable. The big advantage here is that, if you stick to them and use them consistently, you can completely avoid writing delete and nothing will be double-deleted.

Use C++ strings and container classes whenever possible, instead of C-style strings and arrays. Consider using .at(i) rather than [i], because that will force bounds checking. See if your compiler or library can be set to check bounds on [i], at least in debug mode. Segmentation faults can be caused by buffer overruns that write garbage over perfectly good pointers.

Doing those things will considerably reduce the likelihood of segmentation faults and other memory problems. They will doubtless fail to fix everything, and that's why you should use valgrind now and then when you don't have problems, and valgrind and gdb when you do.

JavaScript: function returning an object

In JavaScript, most functions are both callable and instantiable: they have both a [[Call]] and [[Construct]] internal methods.

As callable objects, you can use parentheses to call them, optionally passing some arguments. As a result of the call, the function can return a value.

var player = makeGamePlayer("John Smith", 15, 3);

The code above calls function makeGamePlayer and stores the returned value in the variable player. In this case, you may want to define the function like this:

function makeGamePlayer(name, totalScore, gamesPlayed) {
  // Define desired object
  var obj = {
    name:  name,
    totalScore: totalScore,
    gamesPlayed: gamesPlayed
  };
  // Return it
  return obj;
}

Additionally, when you call a function you are also passing an additional argument under the hood, which determines the value of this inside the function. In the case above, since makeGamePlayer is not called as a method, the this value will be the global object in sloppy mode, or undefined in strict mode.

As constructors, you can use the new operator to instantiate them. This operator uses the [[Construct]] internal method (only available in constructors), which does something like this:

  1. Creates a new object which inherits from the .prototype of the constructor
  2. Calls the constructor passing this object as the this value
  3. It returns the value returned by the constructor if it's an object, or the object created at step 1 otherwise.
var player = new GamePlayer("John Smith", 15, 3);

The code above creates an instance of GamePlayer and stores the returned value in the variable player. In this case, you may want to define the function like this:

function GamePlayer(name,totalScore,gamesPlayed) {
  // `this` is the instance which is currently being created
  this.name =  name;
  this.totalScore = totalScore;
  this.gamesPlayed = gamesPlayed;
  // No need to return, but you can use `return this;` if you want
}

By convention, constructor names begin with an uppercase letter.

The advantage of using constructors is that the instances inherit from GamePlayer.prototype. Then, you can define properties there and make them available in all instances

What 'additional configuration' is necessary to reference a .NET 2.0 mixed mode assembly in a .NET 4.0 project?

I used this config:

<startup useLegacyV2RuntimeActivationPolicy="true">
    <supportedRuntime version="v2.0"/>
    <supportedRuntime version="v4.0"/>
</startup>

Worked for me

How to write :hover condition for a:before and a:after?

You can also restrict your action to just one class using the right pointed bracket (">"), as I have done in this code:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
  <style type="text/css">
    span {
    font-size:12px;
    }
    a {
        color:green;
    }
    .test1>a:hover span {
        display:none;
    }
    .test1>a:hover:before {
        color:red;
        content:"Apple";
    }
  </style>
</head>

<body>
  <div class="test1">
    <a href="#"><span>Google</span></a>
  </div>
  <div class="test2">
    <a href="#"><span>Apple</span></a>
  </div>
</body>

</html>

Note: The hover:before switch works only on the .test1 class

Comparison of DES, Triple DES, AES, blowfish encryption for data

Use AES.

In more details:

  • DES is the old "data encryption standard" from the seventies. Its key size is too short for proper security (56 effective bits; this can be brute-forced, as has been demonstrated more than ten years ago). Also, DES uses 64-bit blocks, which raises some potential issues when encrypting several gigabytes of data with the same key (a gigabyte is not that big nowadays).
  • 3DES is a trick to reuse DES implementations, by cascading three instances of DES (with distinct keys). 3DES is believed to be secure up to at least "2112" security (which is quite a lot, and quite far in the realm of "not breakable with today's technology"). But it is slow, especially in software (DES was designed for efficient hardware implementation, but it sucks in software; and 3DES sucks three times as much).
  • Blowfish is a block cipher proposed by Bruce Schneier, and deployed in some softwares. Blowfish can use huge keys and is believed secure, except with regards to its block size, which is 64 bits, just like DES and 3DES. Blowfish is efficient in software, at least on some software platforms (it uses key-dependent lookup tables, hence performance depends on how the platform handles memory and caches).
  • AES is the successor of DES as standard symmetric encryption algorithm for US federal organizations (and as standard for pretty much everybody else, too). AES accepts keys of 128, 192 or 256 bits (128 bits is already very unbreakable), uses 128-bit blocks (so no issue there), and is efficient in both software and hardware. It was selected through an open competition involving hundreds of cryptographers during several years. Basically, you cannot have better than that.

So, when in doubt, use AES.

Note that a block cipher is a box which encrypts "blocks" (128-bit chunks of data with AES). When encrypting a "message" which may be longer than 128 bits, the message must be split into blocks, and the actual way you do the split is called the mode of operation or "chaining". The naive mode (simple split) is called ECB and has issues. Using a block cipher properly is not easy, and it is more important than selecting between, e.g., AES or 3DES.

How can I list ALL grants a user received?

If you want more than just direct table grants (e.g., grants via roles, system privileges such as select any table, etc.), here are some additional queries:

System privileges for a user:

SELECT PRIVILEGE
  FROM sys.dba_sys_privs
 WHERE grantee = <theUser>
UNION
SELECT PRIVILEGE 
  FROM dba_role_privs rp JOIN role_sys_privs rsp ON (rp.granted_role = rsp.role)
 WHERE rp.grantee = <theUser>
 ORDER BY 1;

Direct grants to tables/views:

SELECT owner, table_name, select_priv, insert_priv, delete_priv, update_priv, references_priv, alter_priv, index_priv 
  FROM table_privileges
 WHERE grantee = <theUser>
 ORDER BY owner, table_name;

Indirect grants to tables/views:

SELECT DISTINCT owner, table_name, PRIVILEGE 
  FROM dba_role_privs rp JOIN role_tab_privs rtp ON (rp.granted_role = rtp.role)
 WHERE rp.grantee = <theUser>
 ORDER BY owner, table_name;

How to Update a Component without refreshing full page - Angular

To refresh the component at regular intervals I found this the best method. In the ngOnInit method setTimeOut function

ngOnInit(): void {
  setTimeout(() => { this.ngOnInit() }, 1000 * 10)
}
//10 is the number of seconds

Get a filtered list of files in a directory

use os.walk to recursively list your files

import os
root = "/home"
pattern = "145992"
alist_filter = ['jpg','bmp','png','gif'] 
path=os.path.join(root,"mydir_to_scan")
for r,d,f in os.walk(path):
    for file in f:
        if file[-3:] in alist_filter and pattern in file:
            print os.path.join(root,file)

How do disable paging by swiping with finger in ViewPager but still be able to swipe programmatically?

The simplest way is to setOnTouchListener and return true for ViewPager.

mPager.setOnTouchListener(new OnTouchListener()
    {           
        @Override
        public boolean onTouch(View v, MotionEvent event)
        {
            return true;
        }
    });

How can I create a text box for a note in markdown?

Use the admonition extension. For mkdocs, it can be configured in the mkdocs.yml file:

markdown_extensions:
    - admonition

Then insert the note in your md files as follows:

!!! note

     This is a note.

See an example here.

Getting title and meta tags from external website

<?php 

// ------------------------------------------------------ 

function curl_get_contents($url) {

    $timeout = 5; 
    $useragent = 'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:27.0) Gecko/20100101 Firefox/27.0'; 

    $ch = curl_init(); 
    curl_setopt($ch, CURLOPT_URL, $url); 
    curl_setopt($ch, CURLOPT_USERAGENT, $useragent); 
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout); 
    $data = curl_exec($ch); 
    curl_close($ch); 

    return $data; 
}

// ------------------------------------------------------ 

function fetch_meta_tags($url) { 

    $html = curl_get_contents($url); 
    $mdata = array(); 

    $doc = new DOMDocument();
    $doc->loadHTML($html);

    $titlenode = $doc->getElementsByTagName('title'); 
    $title = $titlenode->item(0)->nodeValue;

    $metanodes = $doc->getElementsByTagName('meta'); 
    foreach($metanodes as $node) { 
    $key = $node->getAttribute('name'); 
    $val = $node->getAttribute('content'); 
    if (!empty($key)) { $mdata[$key] = $val; } 
    }

    $res = array($url, $title, $mdata); 

    return $res;
}

// ------------------------------------------------------ 

?>

Android Recyclerview GridLayoutManager column spacing

class VerticalGridSpacingDecoration(private val spacing: Int) : RecyclerView.ItemDecoration() {

  override fun getItemOffsets(
    outRect: Rect,
    view: View,
    parent: RecyclerView,
    state: State
  ) {
    val layoutManager = parent.layoutManager as? GridLayoutManager
    if (layoutManager == null || layoutManager.orientation != VERTICAL) {
      return super.getItemOffsets(outRect, view, parent, state)
    }

    val spanCount = layoutManager.spanCount
    val position = parent.getChildAdapterPosition(view)
    val column = position % spanCount
    with(outRect) {
      left = if (column == 0) 0 else spacing / 2
      right = if (column == spanCount.dec()) 0 else spacing / 2
      top = if (position < spanCount) 0 else spacing
    }
  }
}

Delete specific values from column with where condition?

UPDATE myTable 
   SET myColumn = NULL 
 WHERE myCondition

Java. Implicit super constructor Employee() is undefined. Must explicitly invoke another constructor

As others have already mentioned you are required to provide a default constructor public Employee(){} in your Employee class.

What happens is that the compiler automatically provides a no-argument, default constructor for any class without constructors. If your class has no explicit superclass, then it has an implicit superclass of Object, which does have a no-argument constructor. In this case you are declaring a constructor in your class Employee therefore you must provide also the no-argument constructor.

Having said that Employee class should look like this:

Your class Employee

import java.util.Date;

public class Employee
{
      private String name, number;
      private Date date;

      public Employee(){} // No-argument Constructor

      public Employee(String name, String number, Date date)
      {
            setName(name);
            setNumber(number);
            setDate(date);
      }

      public void setName(String n)
      {
            name = n;
      }
      public void setNumber(String n)
      {
            number = n;
            // you can check the format here for correctness
      }
      public void setDate(Date d)
      {
            date = d;
      }

      public String getName()
      {
            return name;
      }
      public String getNumber()
      {
            return number;
      }
      public Date getDate()
      {
            return date;
      }
}

Here is the Java Oracle tutorial - Providing Constructors for Your Classes chapter. Go through it and you will have a clearer idea of what is going on.

How to URL encode in Python 3?

You misread the documentation. You need to do two things:

  1. Quote each key and value from your dictionary, and
  2. Encode those into a URL

Luckily urllib.parse.urlencode does both those things in a single step, and that's the function you should be using.

from urllib.parse import urlencode, quote_plus

payload = {'username':'administrator', 'password':'xyz'}
result = urlencode(payload, quote_via=quote_plus)
# 'password=xyz&username=administrator'

Eclipse - no Java (JRE) / (JDK) ... no virtual machine

The reason you get this error is because eclipse needs a JRE to launch, which it can't find. The first place it searches is the current directory, then the eclipse.ini file and then finally the system path. So if the it can't find the correct jvm(bit versions are different) through any of these three places, it cribs

The recommended way is to edit the eclipse.ini file and tell eclipse where exactly to look for the vm/jre, by including this line in the file:

-vm
[path to your java.exe] (which is generally under "C:\Program Files\Java\jre7\bin")

P.S. To edit the eclipse.ini, you may need to move the it, edit and then paste it back

Source:- wiki

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

You can also use a regular expression, for instance the following piece of code:

char *names
scanf("%m[^\n]", &names)

will get the whole line from stdin, allocating dynamically the amount of space that it takes. After that, of course, you have to free names.

how to include glyphicons in bootstrap 3

I think your particular problem isn't how to use Glyphicons but understanding how Bootstrap files work together.

Bootstrap requires a specific file structure to work. I see from your code you have this:

<link href="bootstrap.css" rel="stylesheet" media="screen">

Your Bootstrap.css is being loaded from the same location as your page, this would create a problem if you didn't adjust your file structure.

But first, let me recommend you setup your folder structure like so:

/css      <-- Bootstrap.css here
/fonts    <-- Bootstrap fonts here
/img
/js       <-- Bootstrap JavaScript here
index.html

If you notice, this is also how Bootstrap structures its files in its download ZIP.

You then include your Bootstrap file like so:

<link href="css/bootstrap.css" rel="stylesheet" media="screen">
or
<link href="./css/bootstrap.css" rel="stylesheet" media="screen">
or
<link href="/css/bootstrap.css" rel="stylesheet" media="screen">

Depending on your server structure or what you're going for.

The first and second are relative to your file's current directory. The second one is just more explicit by saying "here" (./) first then css folder (/css).

The third is good if you're running a web server, and you can just use relative to root notation as the leading "/" will be always start at the root folder.

So, why do this?

Bootstrap.css has this specific line for Glyphfonts:

@font-face {
    font-family: 'Glyphicons Halflings';
    src: url('../fonts/glyphicons-halflings-regular.eot');
    src: url('../fonts/glyphicons-halflings-regular.eot?#iefix') format('embedded-opentype'), url('../fonts/glyphicons-halflings-regular.woff') format('woff'), url('../fonts/glyphicons-halflings-regular.ttf') format('truetype'), url('../fonts/glyphicons-halflings-regular.svg#glyphicons-halflingsregular') format('svg');
}

What you can see is that that Glyphfonts are loaded by going up one directory ../ and then looking for a folder called /fonts and THEN loading the font file.

The URL address is relative to the location of the CSS file. So, if your CSS file is at the same location like this:

/fonts
Bootstrap.css
index.html

The CSS file is going one level deeper than looking for a /fonts folder.

So, let's say the actual location of these files are:

C:\www\fonts
C:\www\Boostrap.css
C:\www\index.html

The CSS file would technically be looking for a folder at:

C:\fonts

but your folder is actually in:

C:\www\fonts

So see if that helps. You don't have to do anything 'special' to load Bootstrap Glyphicons, except make sure your folder structure is set up appropriately.

When you get that fixed, your HTML should simply be:

<span class="glyphicon glyphicon-comment"></span>

Note, you need both classes. The first class glyphicon sets up the basic styles while glyphicon-comment sets the specific image.

How to concatenate a std::string and an int?

This problem can be done in many ways. I will show it in two ways:

  1. Convert the number to string using to_string(i).

  2. Using string streams.

    Code:

    #include <string>
    #include <sstream>
    #include <bits/stdc++.h>
    #include <iostream>
    using namespace std;
    
    int main() {
        string name = "John";
        int age = 21;
    
        string answer1 = "";
        // Method 1). string s1 = to_string(age).
    
        string s1=to_string(age); // Know the integer get converted into string
        // where as we know that concatenation can easily be done using '+' in C++
    
        answer1 = name + s1;
    
        cout << answer1 << endl;
    
        // Method 2). Using string streams
    
        ostringstream s2;
    
        s2 << age;
    
        string s3 = s2.str(); // The str() function will convert a number into a string
    
        string answer2 = "";  // For concatenation of strings.
    
        answer2 = name + s3;
    
        cout << answer2 << endl;
    
        return 0;
    }
    

laravel-5 passing variable to JavaScript

Standard PHP objects

The best way to provide PHP variables to JavaScript is json_encode. When using Blade you can do it like following:

<script>
    var bool = {!! json_encode($bool) !!};
    var int = {!! json_encode($int) !!};
    /* ... */
    var array = {!! json_encode($array_without_keys) !!};
    var object = {!! json_encode($array_with_keys) !!};
    var object = {!! json_encode($stdClass) !!};
</script>

There is also a Blade directive for decoding to JSON. I'm not sure since which version of Laravel but in 5.5 it is available. Use it like following:

<script>
    var array = @json($array);
</script>

Jsonable's

When using Laravel objects e.g. Collection or Model you should use the ->toJson() method. All those classes that implements the \Illuminate\Contracts\Support\Jsonable interface supports this method call. The call returns automatically JSON.

<script>
    var collection = {!! $collection->toJson() !!};
    var model = {!! $model->toJson() !!};
</script>

When using Model class you can define the $hidden property inside the class and those will be filtered in JSON. The $hidden property, as its name describs, hides sensitive content. So this mechanism is the best for me. Do it like following:

class User extends Model
{
    /* ... */

    protected $hidden = [
        'password', 'ip_address' /* , ... */
    ];

    /* ... */
}

And somewhere in your view

<script>
    var user = {!! $user->toJson() !!};
</script>

Comments in Markdown

This works on GitHub:

[](Comment text goes here)

The resulting HTML looks like:

<a href="Comment%20text%20goes%20here"></a>

Which is basically an empty link. Obviously you can read that in the source of the rendered text, but you can do that on GitHub anyway.

How to load an ImageView by URL in Android?

    private Bitmap getImageBitmap(String url) {
        Bitmap bm = null;
        try {
            URL aURL = new URL(url);
            URLConnection conn = aURL.openConnection();
            conn.connect();
            InputStream is = conn.getInputStream();
            BufferedInputStream bis = new BufferedInputStream(is);
            bm = BitmapFactory.decodeStream(bis);
            bis.close();
            is.close();
       } catch (IOException e) {
           Log.e(TAG, "Error getting bitmap", e);
       }
       return bm;
    } 

How to Initialize char array from a string

Here is obscure solution: define macro function:

#define Z(x) \
        (x==0 ? 'A' : \
        (x==1 ? 'B' : \
        (x==2 ? 'C' : '\0')))

char x[] = { Z(0), Z(1), Z(2) };

import android packages cannot be resolved

It seems that your eclipse-workspace (or at least your Project) is broken somehow.

Have you moved your android-sdk/Project recently? If it's not an Android Project anymore, try to look at Preferences->Android for a valid android sdk-location.

If this is correct, try to open a complete new Workspace, and import your sources with File->import->Android Project from existing Source.

If this still doesn't help, make a new android Project and copy the sources manually inside your Project from outside Eclipse. Re-open Eclipse after that, and make a Project->clean

c++ "Incomplete type not allowed" error accessing class reference information (Circular dependency with forward declaration)

If you will place your definitions in this order then the code will be compiled

class Ball;

class Player {
public:
    void doSomething(Ball& ball);
private:
};

class Ball {
public:
    Player& PlayerB;
    float ballPosX = 800;
private:

};

void Player::doSomething(Ball& ball) {
    ball.ballPosX += 10;                   // incomplete type error occurs here.
}

int main()
{
}

The definition of function doSomething requires the complete definition of class Ball because it access its data member.

In your code example module Player.cpp has no access to the definition of class Ball so the compiler issues an error.

Changing cell color using apache poi

For apache POI 3.9 you can use the code bellow:

HSSFCellStyle style = workbook.createCellStyle()
style.setFillForegroundColor(HSSFColor.YELLOW.index)
style.setFillPattern((short) FillPatternType.SOLID_FOREGROUND.ordinal())

The methods for 3.9 version accept short and you should pay attention to the inputs.

Struct like objects in Java

This is a question on Object Oriented Design, not Java the language. It's generally good practice to hide data types within the class and expose only the methods that are part of the class API. If you expose internal data types, you can never change them in the future. If you hide them, your only obligation to the user is the method's return and argument types.

UIButton title text color

In Swift:

Changing the label text color is quite different than changing it for a UIButton. To change the text color for a UIButton use this method:

self.headingButton.setTitleColor(UIColor(red: 107.0/255.0, green: 199.0/255.0, blue: 217.0/255.0), forState: UIControlState.Normal)

What is the difference between XAMPP or WAMP Server & IIS?

WAMP stands for Windows,Apache,Mysql,Php

XAMPP stands for X-os,Apache,Mysql,Php,Perl. (x-os means it can use for any operating system)

Advantages of XAMPP:

  • It is cross-platform software

  • It possesses many other essential modules such as phpMyAdmin, OpenSSL, MediaWiki, WordPress, Joomla and more.

  • it is easy to configure and use.

Advantages of WAMP:

  • It is easy to Use. (Changing Configuration)

  • WAMP is Available for both 64 bit and 32-bit system.

if you are running projects which have specific version requirements WAMP is better choice because you can switch between multiple versions. for example 7x and PHP 5x or Magento2.2.4 won't work on php7.2 but Magento2.3.needs php7.2 or up to work.

i suggest using laragon :

Laragon works out of the box with not only MySQL/MariaDB but also PostgreSQL & MongoDB. With Laragon, they are portable & reliable so you can focus on what matters Laragon is a portable, isolated, fast & powerful universal development environment for PHP, Node.js, Python, Java, Go, Ruby. It is fast, lightweight, easy-to-use and easy-to-extend.

Laragon is great for building and managing modern web applications. It is focused on performance - designed around stability, simplicity, flexibility and freedom.

Laragon is very lightweight and will stay as lean as possible. The core binary itself is less than 2MB and uses less than 4MB RAM when running.

Laragon doesn’t use Windows services. It has its own service orchestration which manages services asynchronously and non-blocking so you’ll find things run fast & smoothly with Laragon.

Advantages of Laragon:

  • Pretty URLs
    Use app.test instead of localhost/app.

  • Portable
    You can move Laragon folder around (to another disks, to another laptops, sync to Cloud,…) without any worries.

  • Isolated
    Laragon has an isolated environment with your OS - it will keep your system clean.

  • Easy Operation

    Unlike others which pre-config for you, Laragon auto-configsall the complicated things. That why you can add another versions of PHP, Python, Ruby, Java, Go, Apache, Nginx, MySQL, PostgreSQL, MongoDB,… effortlessly.

  • Modern & Powerful
    Laragon comes with modern architect which is suitable to build modern web apps. You can work with both Apache & Nginx as they are fully-managed. Also, Laragon makes things a lot easier:Wanna have a Wordpress CMS? Just 1 click.Wanna show your local project to customers? Just 1 click.Wanna enable/disable a PHP extension? Just 1 click.

How to run .jar file by double click on Windows 7 64-bit?

Had to try this:

  1. Open command prompt as admin
  2. Move to the file folder using cd command
  3. Type java.exe -jar *filename*.jar
  4. Press enter

The app should pop right after that.

Using import fs from 'fs'

If we are using TypeScript, we can update the type definition file by running the command npm install @types/node from the terminal or command prompt.

Difference between "as $key => $value" and "as $value" in PHP foreach

A very important place where it is REQUIRED to use the key => value pair in foreach loop is to be mentioned. Suppose you would want to add a new/sub-element to an existing item (in another key) in the $features array. You should do the following:

foreach($features as $key => $feature) {
    $features[$key]['new_key'] = 'new value';  
} 


Instead of this:

foreach($features as $feature) {
    $feature['new_key'] = 'new value';  
} 

The big difference here is that, in the first case you are accessing the array's sub-value via the main array itself with a key to the element which is currently being pointed to by the array pointer.

While in the second (which doesn't work for this purpose) you are assigning the sub-value in the array to a temporary variable $feature which is unset after each loop iteration.

How to remove unique key from mysql table

For those who don't know how to get index_name which mentioned in Devart's answer, or key_name which mentioned in Uday Sawant's answer, you can get it like this:

SHOW INDEX FROM table_name;

This will show all indexes for the given table, then you can pick name of the index or unique key that you want to remove.

Error: Local workspace file ('angular.json') could not be found

With recent version, without --migrate-only I got the repo updated.

I did ng update

The Angular CLI configuration format has been changed, and your existing configuration can be updated automatically by running the following command:

ng update @angular/cli
            Updating karma configuration
            Updating configuration
            Removing old config file (.angular-cli.json)
            Writing config file (angular.json)
            Some configuration options have been changed, please make sure to update any npm scripts which you may have modified.
DELETE .angular-cli.json
CREATE angular.json (3684 bytes)
UPDATE karma.conf.js (1040 bytes)
UPDATE src/tsconfig.spec.json (322 bytes)
UPDATE package.json (1340 bytes)
UPDATE tslint.json (3140 bytes)

How to add item to the beginning of List<T>?

Use the Insert method:

ti.Insert(0, initialItem);

Check number of arguments passed to a Bash script

You should add spaces between test condition:

if [ $# -ne 1 ]; 
    then echo "illegal number of parameters"
fi

I hope this helps.

Rails: select unique values from a column

Model.uniq.pluck(:rating)

# SELECT DISTINCT "models"."rating" FROM "models"

This has the advantages of not using sql strings and not instantiating models

Volatile vs Static in Java

In addition to other answers, I would like to add one image for it(pic makes easy to understand)

enter image description here

static variables may be cached for individual threads. In multi-threaded environment if one thread modifies its cached data, that may not reflect for other threads as they have a copy of it.

volatile declaration makes sure that threads won't cache the data and uses the shared copy only.

image source

What is the difference between Left, Right, Outer and Inner Joins?

Inner join: Only show rows, when has it data from both of the tables.

Outer join: (left/right): Show the all result from the left / right table with the paired row(s), if it exists or not.

Catching "Maximum request length exceeded"

You can solve this by increasing the maximum request length in your web.config:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <system.web>
        <httpRuntime maxRequestLength="102400" />
    </system.web>
</configuration>

The example above is for a 100Mb limit.