Programs & Examples On #Function coverage

How to select different app.config for several build configurations

I have solved this topic with the solution I have found here:

In short what they state there is: "by adding a post-build event.[...] We need to add the following:

if "Debug"=="$(ConfigurationName)" goto :nocopy
del "$(TargetPath).config"
copy "$(ProjectDir)\Release.config" "$(TargetPath).config"

How to save and extract session data in codeigniter

In CodeIgniter you can store your session value as single or also in array format as below:

If you want store any user’s data in session like userId, userName, userContact etc, then you should store in array:

'userId'  => $user->userId,
'userName' => $user->userName,
'userContact '  => $user->userContact 

Get in details with Example Demo :

Find first element by predicate

No, filter does not scan the whole stream. It's an intermediate operation, which returns a lazy stream (actually all intermediate operations return a lazy stream). To convince you, you can simply do the following test:

List<Integer> list = Arrays.asList(1, 10, 3, 7, 5);
int a =
            .peek(num -> System.out.println("will filter " + num))
            .filter(x -> x > 5)

Which outputs:

will filter 1
will filter 10

You see that only the two first elements of the stream are actually processed.

So you can go with your approach which is perfectly fine.

How do I format date value as yyyy-mm-dd using SSIS expression builder?

Correct expression is

"source " + (DT_STR,4,1252)DATEPART( "yyyy" , getdate() ) + "-" +
RIGHT("0" + (DT_STR,4,1252)DATEPART( "mm" , getdate() ), 2) + "-" +
RIGHT("0" + (DT_STR,4,1252)DATEPART( "dd" , getdate() ), 2) +".CSV"

AngularJS POST Fails: Response for preflight has invalid HTTP status code 404

For a Node.js app, in the server.js file before registering all of my own routes, I put the code below. It sets the headers for all responses. It also ends the response gracefully if it is a pre-flight "OPTIONS" call and immediately sends the pre-flight response back to the client without "nexting" (is that a word?) down through the actual business logic routes. Here is my server.js file. Relevant sections highlighted for Stackoverflow use.

// server.js

// ==================

// import the packages we need
var express    = require('express');
var app        = express();
var bodyParser = require('body-parser');
var morgan     = require('morgan');
var jwt        = require('jsonwebtoken'); // used to create, sign, and verify tokens

// ====================================================
// configure app to use bodyParser()
// this will let us get the data from a POST
app.use(bodyParser.urlencoded({ extended: true }));

// Logger

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

//Set CORS header and intercept "OPTIONS" preflight call from AngularJS
var allowCrossDomain = function(req, res, next) {
    res.header('Access-Control-Allow-Origin', '*');
    res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE');
    res.header('Access-Control-Allow-Headers', 'Content-Type');
    if (req.method === "OPTIONS") 

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

// =================================================

var route1 = require("./routes/route1");
var route2 = require("./routes/route2");
var error404 = require("./routes/error404");

// ======================================================

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


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

app.use("/api/v1/route1/", route1);
app.use("/api/v1/route2/", route2);
app.use('/', error404);

// =================

var port = process.env.PORT || 8080;        // set our port
console.log('API Active on port ' + port);

How to easily import multiple sql files into a MySQL database?

In Windows, open a terminal, go to the content folder and write:

copy /b *.sql all_files.sql

This concate all files in only one, making it really quick to import with PhpMyAdmin.

In Linux and macOS, as @BlackCharly pointed out, this will do the trick:

cat *.sql  > .all_files.sql

Important Note: Doing it directly should go well, but it could end up with you stuck in a loop with a massive output file getting bigger and bigger due to the system adding the file to itself. To avoid it, two possible solutions.

A) Put the result in a separate directory to be safe (Thanks @mosh):

mkdir concatSql
cat *.sql  > ./concatSql/all_files.sql

B) Concat them in a file with a different extension and then change it the name. (Thanks @William Turrell)

cat *.sql  > all_files.sql1
mv all_files.sql1 all_files.sql

Could not calculate build plan: Plugin org.apache.maven.plugins:maven-jar-plugin:2.3.2 or one of its dependencies could not be resolved

I solved it now. However it only is solved in Netbeans. Not sure why eclipse still won't take the settings.xml that is changed. The solution is however to remove/comment the User/Password param in settings.xml





PostgreSQL: Which version of PostgreSQL am I running?

If Select version() returns with Memo try using the command this way:

Select version::char(100) 


Select version::varchar(100)

Opening a .ipynb.txt File

What you have on your hands is an IPython Notebook file. (Now renamed to Jupyter Notebook

you can open it using the command ipython notebook filename.ipynb from the directory it is downloaded on to.

If you are on a newer machine, open the file as jupyter notebook filename.ipynb.

do not forget to remove the .txt extension.

the file has a series of python code/statements and markdown text that you can run/inspect/save/share. read more about ipython notebook from the website.

if you do not have IPython installed, you can do

pip install ipython

or check out installation instructions at the ipython website

How to add custom Http Header for C# Web Service Client consuming Axis 1.4 Web service

Here is what worked for me:

protected override System.Net.WebRequest GetWebRequest(Uri uri)
        HttpWebRequest request;
        request = (HttpWebRequest)base.GetWebRequest(uri);
        NetworkCredential networkCredentials =
        Credentials.GetCredential(uri, "Basic");
        if (networkCredentials != null)
            byte[] credentialBuffer = new UTF8Encoding().GetBytes(
            networkCredentials.UserName + ":" +
            request.Headers["Authorization"] =
            "Basic " + Convert.ToBase64String(credentialBuffer);
            request.Headers["Cookie"] = "BCSI-CS-2rtyueru7546356=1";
            request.Headers["Cookie2"] = "$Version=1";
            throw new ApplicationException("No network credentials");
        return request;

Don't forget to set this property:

service.Credentials = new NetworkCredential("username", "password");  

Cookie and Cookie2 are set in header because java service was not accepting the request and I was getting Unauthorized error.

WCF Service , how to increase the timeout?

The best way is to change any setting you want in your code.

Check out the below example:

using(WCFServiceClient client = new WCFServiceClient ())
    client.Endpoint.Binding.SendTimeout = new TimeSpan(0, 1, 30);

Linux command to translate DomainName to IP

Use this

$ dig +short

or this

$ host has address mail is handled by 30 mail is handled by 40 mail is handled by 50 mail is handled by 10 mail is handled by 20

adb command not found in linux environment

adb is in android-sdks/tools directory. You simply type this command: adb logcat.

If you want to your stack traces in a text file use this command: adb logcat > trace.txt. Now your traces are copied into that file.

If it is not working then go to android-sdks/platform-tools then put this command: ./adb logcat > trace.txt. Hope it will helps to you.

iterating quickly through list of tuples

I wonder whether the below method is what you want.

You can use defaultdict.

>>> from collections import defaultdict
>>> s = [('red',1), ('blue',2), ('red',3), ('blue',4), ('red',1), ('blue',4)]
>>> d = defaultdict(list)
>>> for k, v in s:
>>> sorted(d.items())
[('blue', [2, 4, 4]), ('red', [1, 3, 1])]

Connect to Oracle DB using sqlplus

Easy way (using XE):

1). Configure your tnsnames.ora

XE =

You can replace HOST.DOMAIN.COM with IP address, the TCP port by default is 1521 (ckeck it) and look that name of this configuration is XE

2). Using your app named sqlplus:

sqlplus SYSTEM@XE

SYSTEM should be replaced with an authorized USER, and put your password when prompt appear

3). See at firewall for any possibilities of some blocked TCP ports and fix it if appear

How does tuple comparison work in Python?

I had some confusion before regarding integer comparsion, so I will explain it to be more beginner friendly with an example

a = ('A','B','C') # see it as the string "ABC" b = ('A','B','D')

A is converted to its corresponding ASCII ord('A') #65 same for other elements

So, >> a>b # True you can think of it as comparing between string (It is exactly, actually)

the same thing goes for integers too.

x = (1,2,2) # see it the string "123" y = (1,2,3) x > y # False

because (1 is not greater than 1, move to the next, 2 is not greater than 2, move to the next 2 is less than three -lexicographically -)

The key point is mentioned in the answer above

think of it as an element is before another alphabetically not element is greater than an element and in this case consider all the tuple elements as one string.

Explode PHP string by new line

this php function explode string by newline

Attention : new line in Windows is \r\n and in Linux and Unix is \n
this function change all new lines to linux mode then split it.
pay attention that empty lines will be ignored

function splitNewLine($text) {
    return explode("\n",$code);


$a="\r\n\r\n\n\n\r\rsalam\r\nman khobam\rto chi\n\rche khabar\n\r\n\n\r\r\n\nbashe baba raftam\r\n\r\n\r\n\r\n";
print_r( splitNewLine($a) );


    [0] => salam
    [1] => man khobam
    [2] => to chi
    [3] => che khabar
    [4] => bashe baba raftam

Java : Cannot format given Object as a Date

This worked for me:

String dat="02/08/2017";
long date=new SimpleDateFormat("dd/MM/yyyy").parse(dat,newParsePosition(0)).getTime();
java.sql.Date dbDate=new java.sql.Date(date);

Query error with ambiguous column name in SQL

One of your tables has the same column name's which brings a confusion in the query as to which columns of the tables are you referring to. Copy this code and run it.

    v.VendorName, i.InvoiceID, iL.InvoiceSequence, iL.InvoiceLineItemAmount
FROM Vendors AS v
JOIN Invoices AS i ON (v.VendorID = .VendorID)
JOIN InvoiceLineItems AS iL ON (i.InvoiceID = iL.InvoiceID)
    I.InvoiceID IN
        (SELECT iL.InvoiceSequence 
         FROM InvoiceLineItems
         WHERE iL.InvoiceSequence > 1)
    V.VendorName, i.InvoiceID, iL.InvoiceSequence, iL.InvoiceLineItemAmount

Execution failed for task ':app:compileDebugAidl': aidl is missing

I had the same error i fixed it by going to the build.gradle (Module: app) and changed this line from :

 buildToolsVersion "23.0.0 rc1"

to :

buildToolsVersion "22.0.1"

You will need to go the SDK Manager and check if you have the 22.0.1 build tools. If not, you can use the right build tools but avoid the 23.0.0 rc1.

Determine a string's encoding in C#

Note: this was an experiment to see how UTF-8 encoding worked internally. The solution offered by vilicvane, to use a UTF8Encoding object that is initialised to throw an exception on decoding failure, is much simpler, and basically does the same thing.

I wrote this piece of code to differentiate between UTF-8 and Windows-1252. It shouldn't be used for gigantic text files though, since it loads the entire thing into memory and scans it completely. I used it for .srt subtitle files, just to be able to save them back in the encoding in which they were loaded.

The encoding given to the function as ref should be the 8-bit fallback encoding to use in case the file is detected as not being valid UTF-8; generally, on Windows systems, this will be Windows-1252. This doesn't do anything fancy like checking actual valid ascii ranges though, and doesn't detect UTF-16 even on byte order mark.

The theory behind the bitwise detection can be found here:

Basically, the bit range of the first byte determines how many after it are part of the UTF-8 entity. These bytes after it are always in the same bit range.

/// <summary>
/// Reads a text file, and detects whether its encoding is valid UTF-8 or ascii.
/// If not, decodes the text using the given fallback encoding.
/// Bit-wise mechanism for detecting valid UTF-8 based on
/// </summary>
/// <param name="docBytes">The bytes read from the file.</param>
/// <param name="encoding">The default encoding to use as fallback if the text is detected not to be pure ascii or UTF-8 compliant. This ref parameter is changed to the detected encoding.</param>
/// <returns>The contents of the read file, as String.</returns>
public static String ReadFileAndGetEncoding(Byte[] docBytes, ref Encoding encoding)
    if (encoding == null)
        encoding = Encoding.GetEncoding(1252);
    Int32 len = docBytes.Length;
    // byte order mark for utf-8. Easiest way of detecting encoding.
    if (len > 3 && docBytes[0] == 0xEF && docBytes[1] == 0xBB && docBytes[2] == 0xBF)
        encoding = new UTF8Encoding(true);
        // Note that even when initialising an encoding to have
        // a BOM, it does not cut it off the front of the input.
        return encoding.GetString(docBytes, 3, len - 3);
    Boolean isPureAscii = true;
    Boolean isUtf8Valid = true;
    for (Int32 i = 0; i < len; ++i)
        Int32 skip = TestUtf8(docBytes, i);
        if (skip == 0)
        if (isPureAscii)
            isPureAscii = false;
        if (skip < 0)
            isUtf8Valid = false;
            // if invalid utf8 is detected, there's no sense in going on.
        i += skip;
    if (isPureAscii)
        encoding = new ASCIIEncoding(); // pure 7-bit ascii.
    else if (isUtf8Valid)
        encoding = new UTF8Encoding(false);
    // else, retain given encoding. This should be an 8-bit encoding like Windows-1252.
    return encoding.GetString(docBytes);

/// <summary>
/// Tests if the bytes following the given offset are UTF-8 valid, and
/// returns the amount of bytes to skip ahead to do the next read if it is.
/// If the text is not UTF-8 valid it returns -1.
/// </summary>
/// <param name="binFile">Byte array to test</param>
/// <param name="offset">Offset in the byte array to test.</param>
/// <returns>The amount of bytes to skip ahead for the next read, or -1 if the byte sequence wasn't valid UTF-8</returns>
public static Int32 TestUtf8(Byte[] binFile, Int32 offset)
    // 7 bytes (so 6 added bytes) is the maximum the UTF-8 design could support,
    // but in reality it only goes up to 3, meaning the full amount is 4.
    const Int32 maxUtf8Length = 4;
    Byte current = binFile[offset];
    if ((current & 0x80) == 0)
        return 0; // valid 7-bit ascii. Added length is 0 bytes.
    Int32 len = binFile.Length;
    for (Int32 addedlength = 1; addedlength < maxUtf8Length; ++addedlength)
        Int32 fullmask = 0x80;
        Int32 testmask = 0;
        // This code adds shifted bits to get the desired full mask.
        // If the full mask is [111]0 0000, then test mask will be [110]0 0000. Since this is
        // effectively always the previous step in the iteration I just store it each time.
        for (Int32 i = 0; i <= addedlength; ++i)
            testmask = fullmask;
            fullmask += (0x80 >> (i+1));
        // figure out bit masks from level
        if ((current & fullmask) == testmask)
            if (offset + addedlength >= len)
                return -1;
            // Lookahead. Pattern of any following bytes is always 10xxxxxx
            for (Int32 i = 1; i <= addedlength; ++i)
                if ((binFile[offset + i] & 0xC0) != 0x80)
                    return -1;
            return addedlength;
    // Value is greater than the maximum allowed for utf8. Deemed invalid.
    return -1;

How to easily resize/optimize an image size with iOS?

To resize an image I have better (graphical) results by using this function in stead of DrawInRect:

- (UIImage*) reduceImageSize:(UIImage*) pImage newwidth:(float) pWidth
    float lScale = pWidth / pImage.size.width;
    CGImageRef cgImage = pImage.CGImage;
    UIImage   *lResult = [UIImage imageWithCGImage:cgImage scale:lScale
    return lResult;

Aspect ratio is taken care for automatically

Format ints into string of hex

''.join('%02x'%i for i in input)

How do I properly set the Datetimeindex for a Pandas datetime object in a dataframe?

You are not creating datetime index properly,

format = '%Y-%m-%d %H:%M:%S'
df['Datetime'] = pd.to_datetime(df['date'] + ' ' + df['time'], format=format)
df = df.set_index(pd.DatetimeIndex(df['Datetime']))

Could not read JSON: Can not deserialize instance of hello.Country[] out of START_OBJECT token

Another solution:

public class CountryInfoResponse {
  private List<Object> geonames;

Usage of a generic Object-List solved my problem, as there were other Datatypes like Boolean too.

@selector() in Swift?

For future readers, I found that I experienced a problem and was getting an unrecognised selector sent to instance error that was caused by marking the target func as private.

The func MUST be publicly visible to be called by an object with a reference to a selector.

Why is “while ( !feof (file) )” always wrong?

feof() is not very intuitive. In my very humble opinion, the FILE's end-of-file state should be set to true if any read operation results in the end of file being reached. Instead, you have to manually check if the end of file has been reached after each read operation. For example, something like this will work if reading from a text file using fgetc():

#include <stdio.h>

int main(int argc, char *argv[])
  FILE *in = fopen("testfile.txt", "r");

  while(1) {
    char c = fgetc(in);
    if (feof(in)) break;
    printf("%c", c);

  return 0;

It would be great if something like this would work instead:

#include <stdio.h>

int main(int argc, char *argv[])
  FILE *in = fopen("testfile.txt", "r");

  while(!feof(in)) {
    printf("%c", fgetc(in));

  return 0;

How can I clear the NuGet package cache using the command line?

You can use PowerShell too (same as me).

For example:

rm $env:LOCALAPPDATA\NuGet\Cache\*.nupkg

Or 'quiet' mode (without error messages):

rm $env:LOCALAPPDATA\NuGet\Cache\*.nupkg 2> $null

Importing a CSV file into a sqlite3 database table using Python

Based on Guy L solution (Love it) but can handle escaped fields.

import csv, sqlite3

def _get_col_datatypes(fin):
    dr = csv.DictReader(fin) # comma is default delimiter
    fieldTypes = {}
    for entry in dr:
        feildslLeft = [f for f in dr.fieldnames if f not in fieldTypes.keys()]        
        if not feildslLeft: break # We're done
        for field in feildslLeft:
            data = entry[field]

            # Need data to decide
            if len(data) == 0:

            if data.isdigit():
                fieldTypes[field] = "INTEGER"
                fieldTypes[field] = "TEXT"
        # TODO: Currently there's no support for DATE in sqllite

    if len(feildslLeft) > 0:
        raise Exception("Failed to find all the columns data types - Maybe some are empty?")

    return fieldTypes

def escapingGenerator(f):
    for line in f:
        yield line.encode("ascii", "xmlcharrefreplace").decode("ascii")

def csvToDb(csvFile,dbFile,tablename, outputToFile = False):

    # TODO: implement output to file

    with open(csvFile,mode='r', encoding="ISO-8859-1") as fin:
        dt = _get_col_datatypes(fin)

        reader = csv.DictReader(fin)

        # Keep the order of the columns name just as in the CSV
        fields = reader.fieldnames
        cols = []

        # Set field and type
        for f in fields:
            cols.append("\"%s\" %s" % (f, dt[f]))

        # Generate create table statement:
        stmt = "create table if not exists \"" + tablename + "\" (%s)" % ",".join(cols)
        con = sqlite3.connect(dbFile)
        cur = con.cursor()

        reader = csv.reader(escapingGenerator(fin))

        # Generate insert statement:
        stmt = "INSERT INTO \"" + tablename + "\" VALUES(%s);" % ','.join('?' * len(cols))

        cur.executemany(stmt, reader)

How to remove leading and trailing zeros in a string? Python

str.strip is the best approach for this situation, but more_itertools.strip is also a general solution that strips both leading and trailing elements from an iterable:


import more_itertools as mit

iterables = ["231512-n\n","  12091231000-n00000","alphanum0000", "00alphanum"]
pred = lambda x: x in {"0", "\n", " "}
list("".join(mit.strip(i, pred)) for i in iterables)
# ['231512-n', '12091231000-n', 'alphanum', 'alphanum']


Notice, here we strip both leading and trailing "0"s among other elements that satisfy a predicate. This tool is not limited to strings.

See also docs for more examples of

more_itertools is a third-party library installable via > pip install more_itertools.

correct quoting for cmd.exe for multiple arguments

Note the "" at the beginning and at the end!

Run a program and pass a Long Filename

cmd /c write.exe "c:\sample documents\sample.txt"

Spaces in Program Path

cmd /c ""c:\Program Files\Microsoft Office\Office\Winword.exe""

Spaces in Program Path + parameters

cmd /c ""c:\Program Files\demo.cmd"" Parameter1 Param2

Spaces in Program Path + parameters with spaces

cmd /k ""c:\batch files\demo.cmd" "Parameter 1 with space" "Parameter2 with space""

Launch Demo1 and then Launch Demo2

cmd /c ""c:\Program Files\demo1.cmd" & "c:\Program Files\demo2.cmd""

CMD.exe (Command Shell)

Java decimal formatting using String.format?

You want java.text.DecimalFormat.

DecimalFormat df = new DecimalFormat("0.00##");
String result = df.format(34.4959);

Collection that allows only unique items in .NET?

Just to add my 2 cents...

if you need a ValueExistingException-throwing HashSet<T> you can also create your collection easily:

public class ThrowingHashSet<T> : ICollection<T>
    private HashSet<T> innerHash = new HashSet<T>();

    public void Add(T item)
        if (!innerHash.Add(item))
            throw new ValueExistingException();

    public void Clear()

    public bool Contains(T item)
        return innerHash.Contains(item);

    public void CopyTo(T[] array, int arrayIndex)
        innerHash.CopyTo(array, arrayIndex);

    public int Count
        get { return innerHash.Count; }

    public bool IsReadOnly
        get { return false; }

    public bool Remove(T item)
        return innerHash.Remove(item);

    public IEnumerator<T> GetEnumerator()
        return innerHash.GetEnumerator();

    System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        return this.GetEnumerator();

this can be useful for example if you need it in many places...

How to stop app that node.js express 'npm start'

If is very simple, just kill the process..

localmacpro$ ps
  PID TTY           TIME CMD
 5014 ttys000    0:00.05 -bash
 6906 ttys000    0:00.29 npm   
 6907 ttys000    0:06.39 node /Users/roger_macpro/my-project/node_modules/.bin/webpack-dev-server --inline --progress --config build/
 6706 ttys001    0:00.05 -bash
 7157 ttys002    0:00.29 -bash

localmacpro$ kill -9 6907 6906

How to log in to phpMyAdmin with WAMP, what is the username and password?

In my case it was

username : root
password : mysql

Using : Wamp server 3.1.0

Filter data.frame rows by a logical condition

You could use the dplyr package:

filter(expr, cell_type == "hesc")
filter(expr, cell_type == "hesc" | cell_type == "bj fibroblast")

Flutter: RenderBox was not laid out


I used this code to fix the issue of displaying items in the horizontal list.

new Container(
      height: 20,
      child: Row(
        mainAxisAlignment: MainAxisAlignment.end,
        children: <Widget>[
            scrollDirection: Axis.horizontal,
            shrinkWrap: true,
            itemCount: array.length,
            itemBuilder: (context, index){
              return array[index];


I cannot comment Palehorse's answer so I added my own answer. Palehorse's logic is ok but efficiency can be bad with big data sets.

DELETE FROM some_child_table sct 
 WHERE exists (SELECT FROM some_Table st 
                WHERE sct.some_fk_fiel=st.some_id);

DELETE FROM some_table;

It is faster if you have indexes on columns and data set is bigger than few records.

How to show an empty view with a RecyclerView?

I added RecyclerView and alternative ImageView to the RelativeLayout:


        android:src="@mipmap/ic_active_jobs" />

    < xmlns:android=""
        android:layout_height="match_parent" />


and then in Adapter:

public int getItemCount() {
    if (mOrders.size() == 0) {
    } else {
    return mOrders.size();

Error loading MySQLdb Module 'Did you install mysqlclient or MySQL-python?'

I had this issue just recently even with using the python 3 compatible mysqlclient library and managed to solve my issue albeit in a bit of an unorthodox manner. If you are using MySQL 8, give this a try and see if it helps! :)

I simply made a copy of the libmysqlclient.21.dylib file located in my up-to-date installation of MySQL 8.0.13 which is was in /usr/local/mysql/lib and moved that copy under the same name to /usr/lib.

You will need to temporarily disable security integrity protection on your mac however to do this since you won't have or be able to change permissions to anything in /usr/lib without disabling it. You can do this by booting up into the recovery system, click Utilities on the menu at the top, and open up the terminal and enter csrutil disable into the terminal. Just remember to turn security integrity protection back on when you're done doing this! The only difference from the above process will be that you run csrutil enable instead.

You can find out more about how to disable and enable macOS's security integrity protection here.

MVC4 input field placeholder

By default, it does not. However, you can use the MVCHtml5Toolkit NuGet package that has HTML helpers that can output HTML5. For your example, after installing the toolkit you can then use the following HTML helper call:

@Html.Html5TextBoxFor(m => m.Email, InputTypes.InputType.Email)

This will output the following HTML:

<input id="Email" name="Email" placeholder="E-Mail" type="Email" value="">

As can be seen, the placeholder is now correctly rendered.

How do I create/edit a Manifest file?

In Visual Studio 2019 WinForm Projects, it is available under

Project Properties -> Application -> View Windows Settings (button)

enter image description here

force line break in html table cell

You could put the text into a div (or other container) with a width of 50%.

What is the "assert" function?

It is a function that will halt program execution if the value it has evaluated is false. Usually it is surrounded by a macro so that it is not compiled into the resultant binary when compiled with release settings.

It is designed to be used for testing the assumptions you have made. For example:

void strcpy(char* dest, char* src){
    //pointers shouldn't be null

    //copy string
    while(*dest++ = *src++);

The ideal you want is that you can make an error in your program, like calling a function with invalid arguments, and you hit an assert before it segfaults (or fails to work as expected)

How to set default Checked in checkbox ReactJS?

in addition to the correct answer you can just do :P

<input name="remember" type="checkbox" defaultChecked/>

How can you sort an array without mutating the original array?

Try the following

function sortCopy(arr) { 
  return arr.slice(0).sort();

The slice(0) expression creates a copy of the array starting at element 0.

How can I set multiple CSS styles in JavaScript?

@Mircea: It is very much easy to set the multiple styles for an element in a single statement. It doesn't effect the existing properties and avoids the complexity of going for loops or plugins.

   "style", "font-size: 100px; font-style: italic; color:#ff0000;");

BE CAREFUL: If, later on, you use this method to add or alter style properties, the previous properties set using 'setAttribute' will be erased.

Testing if a checkbox is checked with jQuery

function chkb(bool){
return 1;
return 0;

var statusNum=chkb($("#ans").is(':checked'));

statusNum will equal 1 if the checkbox is checked, and 0 if it is not.

EDIT: You could add the DOM to the function as well.

function chkb(el){
return 1;
return 0;

var statusNum=chkb($("#ans"));

How to concatenate text from multiple rows into a single text string in SQL server?

SELECT @name = ''
SELECT @Names = @Names + ',' + Names FROM People
SELECT SUBSTRING(2, @Names, 7998)

This puts the stray comma at the beginning.

However, if you need other columns, or to CSV a child table you need to wrap this in a scalar user defined field (UDF).

You can use XML path as a correlated subquery in the SELECT clause too (but I'd have to wait until I go back to work because Google doesn't do work stuff at home :-)

"Fade" borders in CSS

I know this is old but this seems to work well for me in 2020...

Using the border-image CSS property I was able to quickly manipulate the borders for this fading purpose.

Note: I don't think border-image works well with border-radius... I seen someone saying that somewhere but for this purpose it works well.

1 Liner:


 .bbdr_rfade_1      { border: 4px solid; border-image: linear-gradient(90deg, rgba(60,74,83,0.90), rgba(60,74,83,.00)) 1; border-left:none; border-top:none; border-right:none;  }


<div class = 'bbdr_rfade_1'>Oh I am so going to not up-vote this guy...</div>

Running Facebook application on localhost

None of the answers above worked for me. I am running on FB API 2.5. Mine was a combination of issues that lead to success once resolved

  1. Create a test app to ensure that it is maintained and managed as such and can be disabled when going live
  2. Read the error message properly :) - I had to enable "Web OAuth Login" WITH "Client OAuth Login"
  3. Use to find out what my current IP is
  4. Create an A record on my Domain i.e. that points to my current IP

It's probably not ideal as Dynamic IP's change and one could probably use DynDNS or something similar to make the IP more "static" but it worked for me

boolean in an if statement

In Javascript the idea of boolean is fairly ambiguous. Consider this:

 var bool = 0 
 if(bool){..} //evaluates to false

 if(//uninitialized var) //evaluates to false

So when you're using an if statement, (or any other control statement), one does not have to use a "boolean" type var. Therefore, in my opinion, the "=== true" part of your statement is unnecessary if you know it is a boolean, but absolutely necessary if your value is an ambiguous "truthy" var. More on booleans in javscript can be found here.

fatal: The current branch master has no upstream branch

For me the problem come from the name of my branch : "#name-of-my-branch", without "#" it's work fine!

Apache VirtualHost 403 Forbidden

This may be a permissions problem.

every single parent path to the virtual document root must be Readable, Writable, and Executable by the web server httpd user

according to this page about Apache 403 errors.

Since you're using Allow from all, your order shouldn't matter, but you might try switching it to Deny,Allow to set the default behavior to "allowing."

java.text.ParseException: Unparseable date

Update your format to:

SimpleDateFormat sdf=new SimpleDateFormat("E MMM dd hh:mm:ss Z yyyy");

Const in JavaScript: when to use it and is it necessary?

When it comes to the decision between let and const (both block scoped), always prefer const so that the usage is clear in the code. That way, if you try to redeclare the variable, you'll get an error. If there's no other choice but redeclare it, just switch for let. Note that, as Anthony says, the const values aren't immutable (for instances, a const object can have properties mutated).

When it comes to var, since ES6 is out, I never used it in production code and can't think of a use case for it. One point that might consider one to use it is JavaScript hosting - while let and const are not hoisted, var declaration is. Yet, beware that variables declared with var have a function scope, not a block scope («if declared outside any function, they will be globally available throughout the program; if declared within a function, they are only available within the function itself», in HackerRank - Variable Declaration Keywords). You can think of let as the block scoped version of var.

Merge r brings error "'by' must specify uniquely valid columns"

Rather give names of the column on which you want to merge:

exporttab <- merge(x=dwd_nogap, y=dwd_gap, by.x='x1', by.y='x2', fill=-9999)

What is the difference between json.dump() and json.dumps() in python?

The functions with an s take string parameters. The others take file streams.

Parsing jQuery AJAX response


var parsed_data = JSON.parse(data);

should result in the ability to access the data like you want.


should now show '1'

Maven2 property that indicates the parent directory

The following small profile worked for me. I needed such a configuration for CheckStyle, which I put into the config directory in the root of the project, so I can run it from the main module and from submodules.


It won't work for nested modules, but I'm sure it can be modified for that using several profiles with different exists's. (I have no idea why there should be "../.." in the verification tag and just ".." in the overriden property itself, but it works only in that way.)

What is the difference between rb and r+b modes in file objects

On Windows, 'b' appended to the mode opens the file in binary mode, so there are also modes like 'rb', 'wb', and 'r+b'. Python on Windows makes a distinction between text and binary files; the end-of-line characters in text files are automatically altered slightly when data is read or written. This behind-the-scenes modification to file data is fine for ASCII text files, but it’ll corrupt binary data like that in JPEG or EXE files. Be very careful to use binary mode when reading and writing such files. On Unix, it doesn’t hurt to append a 'b' to the mode, so you can use it platform-independently for all binary files.

Source: Reading and Writing Files

REST API Authentication

I've been using the JWT authentication. Works just fine in my application.

There is an authentication method that will require the user credentials. This method validates the credentials and returns an access token in case of success.

This token must be sent to every other method in my Web API in the header of the request.

It's pretty easy to implement, and very easy to test.

Android Studio - local path doesn't exist

If you have run into this problem while updating to android studio version 0.3.3 or 0.3.4 then you need to remove gradle 1.8 jars from android-studio/plugins/gradle/lib

rm android-studio/plugins/gradle/lib/gradle-*-1.8.jar 

Excel formula to reference 'CELL TO THE LEFT'

When creating a User Defined Function, I found out that the other answers involving the functions OFFSET and INDIRECT cannot be applied.

Instead, you have to use Application.Caller to refer to the cell the User Defined Function (UDF) has been used in. In a second step, you convert the column's index to the corresponding column's name.
Finally, you are able to reference the left cell using the active worksheet's Range function.

Function my_user_defined_function(argument1, argument2)
    ' Way to convert a column number to its name copied from StackOverflow
    ' Answer by Siddarth Rout (
    ' License (if applicable due to the small amount of code): CC BY-SA 3.0
    colName = Split(Cells(, (Application.Caller(1).Column - 1)).Address, "$")(1)

    rowNumber = Application.Caller(1).Row

    left_cell_value = ActiveSheet.Range(colName & rowNumber).Value

    ' Now do something with left_cell_value

Multiple Inheritance in C#

This is along the lines of Lawrence Wenham's answer, but depending on your use case, it may or may not be an improvement -- you don't need the setters.

public interface IPerson {
  int GetAge();
  string GetName();

public interface IGetPerson {
  IPerson GetPerson();

public static class IGetPersonAdditions {
  public static int GetAgeViaPerson(this IGetPerson getPerson) { // I prefer to have the "ViaPerson" in the name in case the object has another Age property.
    IPerson person = getPerson.GetPersion();
    return person.GetAge();
  public static string GetNameViaPerson(this IGetPerson getPerson) {
    return getPerson.GetPerson().GetName();

public class Person: IPerson, IGetPerson {
  private int Age {get;set;}
  private string Name {get;set;}
  public IPerson GetPerson() {
    return this;
  public int GetAge() {  return Age; }
  public string GetName() { return Name; }

Now any object that knows how to get a person can implement IGetPerson, and it will automatically have the GetAgeViaPerson() and GetNameViaPerson() methods. From this point, basically all Person code goes into IGetPerson, not into IPerson, other than new ivars, which have to go into both. And in using such code, you don't have to be concerned about whether or not your IGetPerson object is itself actually an IPerson.

$(document).ready equivalent without jQuery

Here's what I use, it's fast and covers all bases I think; works for everything except IE<9.

(() => { function fn() {
    // "On document ready" commands:
  if (document.readyState != 'loading') {fn()}
  else {document.addEventListener('DOMContentLoaded', fn)}

This seems to catch all cases:

  • fires immediately if the DOM is already ready (if the DOM is not "loading", but either "interactive" or "complete")
  • if the DOM is still loading, it sets up an event listener for when the DOM is available (interactive).

The DOMContentLoaded event is available in IE9 and everything else, so I personally think it's OK to use this. Rewrite the arrow function declaration to a regular anonymous function if you're not transpiling your code from ES2015 to ES5.

If you want to wait until all assets are loaded, all images displayed etc then use window.onload instead.

no default constructor exists for class

A default constructor is a constructor that either has no parameters, or if it has parameters, all the parameters have default values.

C++ passing an array pointer as a function argument

I'm guessing this will help.

When passed as functions arguments, arrays act the same way as pointers. So you don't need to reference them. Simply type: int x[] or int x[a] . Both ways will work. I guess its the same thing Konrad Rudolf was saying, figured as much.

Can't find keyplane that supports type 4 for keyboard iPhone-Portrait-NumberPad; using 3876877096_Portrait_iPhone-Simple-Pad_Default

I too had this problem after updating to the latest Xcode Beta. The settings on the simulator are refreshed, so the laptop (external) keyboard was being detected. If you simply press:

iOS Simulator -> Hardware -> Keyboard -> Connect Hardware Keyboard

so that the entry is UNchecked then the software keyboard will be displayed once again.

CSS: Truncate table cells, but fit as much as possible

The problem is the 'table-layout:fixed' which create evenly-spaced-fixed-width columns. But disabling this css-property will kill the text-overflow because the table will become as large as possible (and than there is noting to overflow).

I'm sorry but in this case Fred can't have his cake and eat it to.. unless the landlord gives Celldito less space to work with in the first place, Fred cannot use his..

Access-Control-Allow-Origin error sending a jQuery Post to Google API's

I solved the Access-Control-Allow-Origin error modifying the dataType parameter to dataType:'jsonp' and adding a crossDomain:true


    url: ''+key,
    data: myData,
    type: 'GET',
    crossDomain: true,
    dataType: 'jsonp',
    success: function() { alert("Success"); },
    error: function() { alert('Failed!'); },
    beforeSend: setHeader

How to Sign an Already Compiled Apk

fastest way is by signing with the debug keystore:

jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore ~/.android/debug.keystore app.apk androiddebugkey -storepass android

or on Windows:

jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore %USERPROFILE%/.android/debug.keystore test.apk androiddebugkey -storepass android

Convert varchar2 to Date ('MM/DD/YYYY') in PL/SQL

Easiest way is probably to convert from a VARCHAR to a DATE; then format it back to a VARCHAR again in the format you want;


An SQLfiddle to test with.

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

I had the same issue: if I doubleclick on a jar executable file, and my Java application does not start.

So tried to change manually also registry key, but it didn't help me. Tried to reinstall JDK newer/older without any result. (I have several versions of Java)

And I've solved it only using jarfix program. Jarfix automatically fixed .jar association problem on Windows system. (check regedit: PC\HKEY_CLASSES_ROOT\jarfile\shell\open\command)

What says Johann Nepomuk Löfflmann:

The root cause for the problem above is, that a program has stolen the .jar association. If you have installed the Java Runtime Environment the first time, the file type called "jar" is assigned to javaw.exe correctly. "jar" is an abbreviation for "java archive" and javaw.exe is the correct program to execute a .jar. However, on Windows any program can steal a file type at any time even if it is already associated with a program. Many zip/unzip programs prefer to do this, because a jar is stored in the .zip format. If you doubleclick on a .jar, your pack program opens the file, rather than javaw runs the program, because your pack program ignores the meta information which are also stored in a .jar. In the Oracle bug database there is the low-priority report 4912211 "add mechanism to restore hijacked .jar and .jnlp file extensions", but it has been closed as "Closed, Will Not Fix".

You may also miss the file connection with .jar if you are using a free OpenJDK without an installer.

Notice: my OS is Windows 10, but logic is the same for 7, 8 and so on.

Helpful links:

Traverse all the Nodes of a JSON Object Tree with JavaScript

The best solution for me was the following:

simple and without using any framework

    var doSomethingForAll = function (arg) {
       if (arg != undefined && arg.length > 0) {
   (item) {
                  // do something for item
                  doSomethingForAll (item.subitem)

How to stop/cancel 'git log' command in terminal?

You can hit the key q (for quit) and it should take you to the prompt.

Please see this link.

iOS 11, 12, and 13 installed certificates not trusted automatically (self signed)

This has happened to me also, after undating to IOS11 on my iPhone. When I try to connect to the corporate network it bring up the corporate cert and says it isn't trusted. I press the 'trust' button and the connection fails and the cert does not appear in the trusted certs list.

How to wrap async function calls into a sync function in Node.js or Javascript?

If function Fiber really turns async function sleep into sync

Yes. Inside the fiber, the function waits before logging ok. Fibers do not make async functions synchronous, but allow to write synchronous-looking code that uses async functions and then will run asynchronously inside a Fiber.

From time to time I find the need to encapsulate an async function into a sync function in order to avoid massive global re-factoring.

You cannot. It is impossible to make asynchronous code synchronous. You will need to anticipate that in your global code, and write it in async style from the beginning. Whether you wrap the global code in a fiber, use promises, promise generators, or simple callbacks depends on your preferences.

My objective is to minimize impact on the caller when data acquisition method is changed from sync to async

Both promises and fibers can do that.

How to force the browser to reload cached CSS and JavaScript files

Changing the filename will work. But that's not usually the simplest solution.

An HTTP cache-control header of 'no-cache' doesn't always work, as you've noticed. The HTTP 1.1 spec allows wiggle-room for user-agents to decide whether or not to request a new copy. (It's non-intuitive if you just look at the names of the directives. Go read the actual HTTP 1.1 spec for cache... it makes a little more sense in context.)

In a nutshell, if you want iron-tight cache-control use

Cache-Control: no-cache, no-store, must-revalidate

in your response headers.

How to align iframe always in the center

I think if you add margin: auto; to the div below it should work.

div#iframe-wrapper iframe {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    margin: auto;
    right: 100px;
    height: 100%;
    width: 100%;

SELECT only rows that contain only alphanumeric characters in MySQL

Try this

select count(*) from table where cast(col as double) is null;

SQL Statement using Where clause with multiple values

SELECT PersonName, songName, status
FROM table
WHERE name IN ('Holly', 'Ryan')

If you are using parametrized Stored procedure:

  1. Pass in comma separated string
  2. Use special function to split comma separated string into table value variable
  3. Use INNER JOIN ON t.PersonName = newTable.PersonName using a table variable which contains passed in names

How come I can't remove the blue textarea border in Twitter Bootstrap?

Work out computed styles via an inspector

For future reference you can work out computed styles via an inspector

Ineligible Devices section appeared in Xcode 6.x.x

I found the following useful:

  1. Connect to the new device, go to itunes, make sure you sync the device (you might have a certificate issue)
  2. Follow NateJC's advice (i.e. switch devices and switch back again)

Merge Two Lists in R

This is a very simple adaptation of the modifyList function by Sarkar. Because it is recursive, it will handle more complex situations than mapply would, and it will handle mismatched name situations by ignoring the items in 'second' that are not in 'first'.

appendList <- function (x, val) 
    stopifnot(is.list(x), is.list(val))
    xnames <- names(x)
    for (v in names(val)) {
        x[[v]] <- if (v %in% xnames && is.list(x[[v]]) && is.list(val[[v]])) 
            appendList(x[[v]], val[[v]])
        else c(x[[v]], val[[v]])

> appendList(first,second)
[1] 1 2

[1] 2 3

[1] 3 4

How can you use php in a javascript function

You can't run PHP code with Javascript. When the user recieves the page, the server will have evaluated and run all PHP code, and taken it out. So for example, this will work:

alert( <?php echo "\"Hello\""; ?> );

Because server will have evaluated it to this:


However, you can't perform any operations in PHP with it.


function Inc()
$num = 2;
echo $num;

Will simply have been evaluated to this:

function Inc()

If you wan't to call a PHP script, you'll have to call a different page which returns a value from a set of parameters.

This, for example, will work:


$num = $_POST["num"];
echo $num * 2;

Javascript(jQuery) (on another page):

$.post('script.php', { num: 5 }, function(result) { 

This should alert 10.

Good luck!

Edit: Just incrementing a number on the page can be done easily in jQuery like this:

Youtube autoplay not working on mobile devices with embedded HTML5 player

The code below was tested on iPhone, iPad (iOS13), Safari (Catalina). It was able to autoplay the YouTube video on all devices. Make sure the video is muted and the playsinline parameter is on. Those are the magic parameters that make it work.

<!DOCTYPE html>
        <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=2.0, minimum-scale=1.0, user-scalable=yes">
<!-- 1. The <iframe> (video player) will replace this <div> tag. -->
<div id="player"></div>

  // 2. This code loads the IFrame Player API code asynchronously.
  var tag = document.createElement('script');

  tag.src = "";
  var firstScriptTag = document.getElementsByTagName('script')[0];
  firstScriptTag.parentNode.insertBefore(tag, firstScriptTag);

  // 3. This function creates an <iframe> (and YouTube player)
  //    after the API code downloads.
  var player;
  function onYouTubeIframeAPIReady() {
    player = new YT.Player('player', {
      width: '100%',
      videoId: 'osz5tVY97dQ',
      playerVars: { 'autoplay': 1, 'playsinline': 1 },
      events: {
        'onReady': onPlayerReady

  // 4. The API will call this function when the video player is ready.
  function onPlayerReady(event) {;;

iPhone/iOS JSON parsing tutorial

try out with this fastest JSON framework JSONKit. it's faster than normal JSON framework.

How to get file path in iPhone app

Since it is your files in your app bundle, I think you can use pathForResource:ofType: to get the full pathname of your file.

Here is an example:

NSString* filePath = [[NSBundle mainBundle] pathForResource:@"your_file_name" 

Difference between RegisterStartupScript and RegisterClientScriptBlock?

Here's a simplest example from ASP.NET Community, this gave me a clear understanding on the concept....

what difference does this make?

For an example of this, here is a way to put focus on a text box on a page when the page is loaded into the browser—with Visual Basic using the RegisterStartupScript method:

Page.ClientScript.RegisterStartupScript(Me.GetType(), "Testing", _ 
"document.forms[0]['TextBox1'].focus();", True)

This works well because the textbox on the page is generated and placed on the page by the time the browser gets down to the bottom of the page and gets to this little bit of JavaScript.

But, if instead it was written like this (using the RegisterClientScriptBlock method):

Page.ClientScript.RegisterClientScriptBlock(Me.GetType(), "Testing", _
"document.forms[0]['TextBox1'].focus();", True)

Focus will not get to the textbox control and a JavaScript error will be generated on the page

The reason for this is that the browser will encounter the JavaScript before the text box is on the page. Therefore, the JavaScript will not be able to find a TextBox1.

Is there a reason for C#'s reuse of the variable in a foreach?

The compiler declares the variable in a way that makes it highly prone to an error that is often difficult to find and debug, while producing no perceivable benefits.

Your criticism is entirely justified.

I discuss this problem in detail here:

Closing over the loop variable considered harmful

Is there something you can do with foreach loops this way that you couldn't if they were compiled with an inner-scoped variable? or is this just an arbitrary choice that was made before anonymous methods and lambda expressions were available or common, and which hasn't been revised since then?

The latter. The C# 1.0 specification actually did not say whether the loop variable was inside or outside the loop body, as it made no observable difference. When closure semantics were introduced in C# 2.0, the choice was made to put the loop variable outside the loop, consistent with the "for" loop.

I think it is fair to say that all regret that decision. This is one of the worst "gotchas" in C#, and we are going to take the breaking change to fix it. In C# 5 the foreach loop variable will be logically inside the body of the loop, and therefore closures will get a fresh copy every time.

The for loop will not be changed, and the change will not be "back ported" to previous versions of C#. You should therefore continue to be careful when using this idiom.

Read input stream twice

You can wrap input stream with PushbackInputStream. PushbackInputStream allows to unread ("write back") bytes which were already read, so you can do like this:

public class StreamTest {
  public static void main(String[] args) throws IOException {
    byte[] bytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

    InputStream originalStream = new ByteArrayInputStream(bytes);

    byte[] readBytes = getBytes(originalStream, 3);
    printBytes(readBytes); // prints: 1 2 3

    readBytes = getBytes(originalStream, 3);
    printBytes(readBytes); // prints: 4 5 6

    // now let's wrap it with PushBackInputStream

    originalStream = new ByteArrayInputStream(bytes);

    InputStream wrappedStream = new PushbackInputStream(originalStream, 10); // 10 means that maximnum 10 characters can be "written back" to the stream

    readBytes = getBytes(wrappedStream, 3);
    printBytes(readBytes); // prints 1 2 3

    ((PushbackInputStream) wrappedStream).unread(readBytes, 0, readBytes.length);

    readBytes = getBytes(wrappedStream, 3);
    printBytes(readBytes); // prints 1 2 3


  private static byte[] getBytes(InputStream is, int howManyBytes) throws IOException {
    System.out.print("Reading stream: ");

    byte[] buf = new byte[howManyBytes];

    int next = 0;
    for (int i = 0; i < howManyBytes; i++) {
      next =;
      if (next > 0) {
        buf[i] = (byte) next;
    return buf;

  private static void printBytes(byte[] buffer) throws IOException {
    System.out.print("Reading stream: ");

    for (int i = 0; i < buffer.length; i++) {
      System.out.print(buffer[i] + " ");


Please note that PushbackInputStream stores internal buffer of bytes so it really creates a buffer in memory which holds bytes "written back".

Knowing this approach we can go further and combine it with FilterInputStream. FilterInputStream stores original input stream as a delegate. This allows to create new class definition which allows to "unread" original data automatically. The definition of this class is following:

public class TryReadInputStream extends FilterInputStream {
  private final int maxPushbackBufferSize;

  * Creates a <code>FilterInputStream</code>
  * by assigning the  argument <code>in</code>
  * to the field <code></code> so as
  * to remember it for later use.
  * @param in the underlying input stream, or <code>null</code> if
  *           this instance is to be created without an underlying stream.
  public TryReadInputStream(InputStream in, int maxPushbackBufferSize) {
    super(new PushbackInputStream(in, maxPushbackBufferSize));
    this.maxPushbackBufferSize = maxPushbackBufferSize;

   * Reads from input stream the <code>length</code> of bytes to given buffer. The read bytes are still avilable
   * in the stream
   * @param buffer the destination buffer to which read the data
   * @param offset  the start offset in the destination <code>buffer</code>
   * @aram length how many bytes to read from the stream to buff. Length needs to be less than
   *        <code>maxPushbackBufferSize</code> or IOException will be thrown
   * @return number of bytes read
   * @throws in case length is
  public int tryRead(byte[] buffer, int offset, int length) throws IOException {

    // NOTE: below reading byte by byte instead of "int bytesRead =, 0, maxBytesOfResponseToLog);"
    // because read() guarantees to read a byte

    int bytesRead = 0;

    int nextByte = 0;

    for (int i = 0; (i < length) && (nextByte >= 0); i++) {
      nextByte = read();
      if (nextByte >= 0) {
        buffer[offset + bytesRead++] = (byte) nextByte;

    if (bytesRead > 0) {
      ((PushbackInputStream) in).unread(buffer, offset, bytesRead);

    return bytesRead;


  public byte[] tryRead(int maxBytesToRead) throws IOException {

    ByteArrayOutputStream baos = new ByteArrayOutputStream(); // as ByteArrayOutputStream to dynamically allocate internal bytes array instead of allocating possibly large buffer (if maxBytesToRead is large)

    // NOTE: below reading byte by byte instead of "int bytesRead =, 0, maxBytesOfResponseToLog);"
    // because read() guarantees to read a byte

    int nextByte = 0;

    for (int i = 0; (i < maxBytesToRead) && (nextByte >= 0); i++) {
      nextByte = read();
      if (nextByte >= 0) {
        baos.write((byte) nextByte);

    byte[] buffer = baos.toByteArray();

    if (buffer.length > 0) {
      ((PushbackInputStream) in).unread(buffer, 0, buffer.length);

    return buffer;


  private void validateMaxLength(int length) throws IOException {
    if (length > maxPushbackBufferSize) {
      throw new IOException(
        "Trying to read more bytes than maxBytesToRead. Max bytes: " + maxPushbackBufferSize + ". Trying to read: " +


This class has two methods. One for reading into existing buffer (defintion is analogous to calling public int read(byte b[], int off, int len) of InputStream class). Second which returns new buffer (this may be more effective if the size of buffer to read is unknown).

Now let's see our class in action:

public class StreamTest2 {
  public static void main(String[] args) throws IOException {
    byte[] bytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

    InputStream originalStream = new ByteArrayInputStream(bytes);

    byte[] readBytes = getBytes(originalStream, 3);
    printBytes(readBytes); // prints: 1 2 3

    readBytes = getBytes(originalStream, 3);
    printBytes(readBytes); // prints: 4 5 6

    // now let's use our TryReadInputStream

    originalStream = new ByteArrayInputStream(bytes);

    InputStream wrappedStream = new TryReadInputStream(originalStream, 10);

    readBytes = ((TryReadInputStream) wrappedStream).tryRead(3); // NOTE: no manual call to "unread"(!) because TryReadInputStream handles this internally
    printBytes(readBytes); // prints 1 2 3

    readBytes = ((TryReadInputStream) wrappedStream).tryRead(3); 
    printBytes(readBytes); // prints 1 2 3

    readBytes = ((TryReadInputStream) wrappedStream).tryRead(3);
    printBytes(readBytes); // prints 1 2 3

    // we can also call normal read which will actually read the bytes without "writing them back"
    readBytes = getBytes(wrappedStream, 3);
    printBytes(readBytes); // prints 1 2 3

    readBytes = getBytes(wrappedStream, 3);
    printBytes(readBytes); // prints 4 5 6

    readBytes = ((TryReadInputStream) wrappedStream).tryRead(3); // now we can try read next bytes
    printBytes(readBytes); // prints 7 8 9

    readBytes = ((TryReadInputStream) wrappedStream).tryRead(3); 
    printBytes(readBytes); // prints 7 8 9



Best way to do multiple constructors in PHP

You could always add an extra parameter to the constructor called something like mode and then perform a switch statement on it...

class myClass 
    var $error ;
    function __construct ( $data, $mode )
        $this->error = false
        switch ( $mode )
            'id' : processId ( $data ) ; break ;
            'row' : processRow ( $data ); break ;
            default : $this->error = true ; break ;

     function processId ( $data ) { /* code */ }
     function processRow ( $data ) { /* code */ }

$a = new myClass ( $data, 'id' ) ;
$b = new myClass ( $data, 'row' ) ;
$c = new myClass ( $data, 'something' ) ;

if ( $a->error )
   exit ( 'invalid mode' ) ;
if ( $b->error )
   exit ('invalid mode' ) ;
if ( $c->error )
   exit ('invalid mode' ) ;

Also with that method at any time if you wanted to add more functionality you can just add another case to the switch statement, and you can also check to make sure someone has sent the right thing through - in the above example all the data is ok except for C as that is set to "something" and so the error flag in the class is set and control is returned back to the main program for it to decide what to do next (in the example I just told it to exit with an error message "invalid mode" - but alternatively you could loop it back round until valid data is found).

How to create a POJO?

When you aren't doing anything to make your class particularly designed to work with a given framework, ORM, or other system that needs a special sort of class, you have a Plain Old Java Object, or POJO.

Ironically, one of the reasons for coining the term is that people were avoiding them in cases where they were sensible and some people concluded that this was because they didn't have a fancy name. Ironic, because your question demonstrates that the approach worked.

Compare the older POD "Plain Old Data" to mean a C++ class that doesn't do anything a C struct couldn't do (more or less, non-virtual members that aren't destructors or trivial constructors don't stop it being considered POD), and the newer (and more directly comparable) POCO "Plain Old CLR Object" in .NET.

Best way to compare dates in Android

Calendar toDayCalendar = Calendar.getInstance();
Date date1 = toDayCalendar.getTime();

Calendar tomorrowCalendar = Calendar.getInstance();
Date date2 = tomorrowCalendar.getTime();

// date1 is a present date and date2 is tomorrow date

if ( date1.compareTo(date2) < 0 ) {

  //  0 comes when two date are same,
  //  1 comes when date1 is higher then date2
  // -1 comes when date1 is lower then date2


How to align an input tag to the center without specifying the width?

You need to put the text-align:center on the containing div, not on the input itself.

phpinfo() - is there an easy way for seeing it?

Use the command line.

touch /var/www/project1/html/phpinfo.php && echo '<?php phpinfo(); ?>' >> /var/www/project1/html/phpinfo.php && firefox --url localhost/project1/phpinfo.php

Something like that? Idk!

Determine if Android app is being used for the first time

I made a simple class to check if your code is running for the first time/ n-times!


Create a unique preferences

FirstTimePreference prefFirstTime = new FirstTimePreference(getApplicationContext());

Use runTheFirstTime, choose a key to check your event

if (prefFirstTime.runTheFirstTime("myKey")) {
    Toast.makeText(this, "Test myKey & coutdown: " + prefFirstTime.getCountDown("myKey"),

Use runTheFirstNTimes, choose a key and how many times execute

if(prefFirstTime.runTheFirstNTimes("anotherKey" , 5)) {
    Toast.makeText(this, "ciccia Test coutdown: "+ prefFirstTime.getCountDown("anotherKey"),
  • Use getCountDown() to better handle your code

How to open every file in a folder

you should try using os.walk

yourpath = 'path'

import os
for root, dirs, files in os.walk(yourpath, topdown=False):
    for name in files:
        print(os.path.join(root, name))
    for name in dirs:
        print(os.path.join(root, name))

.NET Events - What are object sender & EventArgs e?

The sender is the control that the action is for (say OnClick, it's the button).

The EventArgs are arguments that the implementor of this event may find useful. With OnClick it contains nothing good, but in some events, like say in a GridView 'SelectedIndexChanged', it will contain the new index, or some other useful data.

What Chris is saying is you can do this:

protected void someButton_Click (object sender, EventArgs ea)
    Button someButton = sender as Button;
    if(someButton != null)
        someButton.Text = "I was clicked!";

Best way to define private methods for a class in Objective-C

As other people said defining private methods in the @implementation block is OK for most purposes.

On the topic of code organization - I like to keep them together under pragma mark private for easier navigation in Xcode

@implementation MyClass 
// .. public methods

# pragma mark private 
// ...


Cut Corners using CSS

Another one solution: html:

<div class="background">
  <div class="container">Hello world!</div>


.background {
  position: relative;
  width: 50px;
  height: 50px;
  border-right: 150px solid lightgreen;
  border-bottom: 150px solid lightgreen;
  border-radius: 10px;
.background::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 0;
  height: 0;
  border: 25px solid lightgreen;
  border-top-color: transparent;
  border-left-color: transparent;
.container {
  position: absolute;
  padding-left: 25px;
  padding-top: 25px;
  font-size: 38px;
  font-weight: bolder;

Twig: in_array or similar possible within if statement?

another example following @jake stayman:

{% for key, item in row.divs %}
    {% if (key not in [1,2,9]) %} // eliminate element 1,2,9
        <li>{{ item }}</li>
    {% endif %}
{% endfor %}

Define preprocessor macro through CMake?

To do this for a specific target, you can do the following:

target_compile_definitions(my_target PRIVATE FOO=1 BAR=1)

You should do this if you have more than one target that you're building and you don't want them all to use the same flags. Also see the official documentation on target_compile_definitions.

Smart way to truncate long strings

Sometimes file names are numbered, where the index may be at the beginning or the end. So I wanted to shorten from the center of the string:

function stringTruncateFromCenter(str, maxLength) {
    const midChar = "…";      // character to insert into the center of the result
    var left, right;

    if (str.length <= maxLength) return str;

    // length of beginning part      
    left = Math.ceil(maxLength / 2);

    // start index of ending part   
    right = str.length - Math.floor(maxLength / 2) + 1;   

    return str.substr(0, left) + midChar + str.substring(right);

Be aware that I used a fill character here with more than 1 byte in UTF-8.

Java 8 List<V> into Map<K, V>

Here's another one in case you don't want to use Collectors.toMap()

Map<String, Choice> result =<String, Choice>::new, 
                           (m, c) -> m.put(c.getName(), c),
                           (m, u) -> {});

What's the simplest way to list conflicted files in Git?

Here is a fool-proof way:

grep -H -r "<<<<<<< HEAD" /path/to/project/dir

Does hosts file exist on the iPhone? How to change it?

This doesn't directly answer your question, but it does solve your problem...

What make of router do you have? Your router firmware may allow you to set DNS records for your local network. This is what I do with the Tomato firmware

Python convert csv to xlsx

Simple two line code solution using pandas

  import pandas as pd

  read_file = pd.read_csv ('File name.csv')
  read_file.to_excel ('File name.xlsx', index = None, header=True)

Oracle: If Table Exists


This function verifies that the input parameter string is a qualified SQL identifier of an existing SQL object.



DBFiddle Demo

How to bring a window to the front?

I had the same problem with bringing a JFrame to the front under Ubuntu (Java 1.6.0_10). And the only way I could resolve it is by providing a WindowListener. Specifically, I had to set my JFrame to always stay on top whenever toFront() is invoked, and provide windowDeactivated event handler to setAlwaysOnTop(false).

So, here is the code that could be placed into a base JFrame, which is used to derive all application frames.

public void setVisible(final boolean visible) {
  // make sure that frame is marked as not disposed if it is asked to be visible
  if (visible) {
  // let's handle visibility...
  if (!visible || !isVisible()) { // have to check this condition simply because super.setVisible(true) invokes toFront if frame was already visible
  // ...and bring frame to the front.. in a strange and weird way
  if (visible) {

public void toFront() {
  int state = super.getExtendedState();
  state &= ~JFrame.ICONIFIED;

Whenever your frame should be displayed or brought to front call frame.setVisible(true).

Since I moved to Ubuntu 9.04 there seems to be no need in having a WindowListener for invoking super.setAlwaysOnTop(false) -- as can be observed; this code was moved to the methods toFront() and setVisible().

Please note that method setVisible() should always be invoked on EDT.

CSS: How to align vertically a "label" and "input" inside a "div"?

Wrap the label and input in another div with a defined height. This may not work in IE versions lower than 8.

top:0; bottom:0; left:0; right:0;

How to find good looking font color if background color is known?

Okay, this is still not the best possible solution, but a nice point to start. I wrote a little Java app that calculates the contrast ratio of two colors and only processes colors with a ratio of 5:1 or better - this ratio and the formula I use has been released by the W3C and will probably replace the current recommendation (which I consider very limited). It creates a file in the current working dir named "chosen-font-colors.html", with the background color of your choice and a line of text in every color that passed this W3C test. It expects a single argument, being the background color.

E.g. you can call it like this

java FontColorChooser 33FFB4

then just open the generated HTML file in a browser of your choice and choose a color from the list. All colors given passed the W3C test for this background color. You can change the cut off by replacing 5 with a number of your choice (lower numbers allow weaker contrasts, e.g. 3 will only make sure contrast is 3:1, 10 will make sure it is at least 10:1) and you can also cut off to avoid too high contrasts (by making sure it is smaller than a certain number), e.g. adding

|| cDiff > 18.0

to the if clause will make sure contrast won't be too extreme, as too extreme contrasts can stress your eyes. Here's the code and have fun playing around with it a bit :-)


/* For text being readable, it must have a good contrast difference. Why?
 * Your eye has receptors for brightness and receptors for each of the colors
 * red, green and blue. However, it has much more receptors for brightness
 * than for color. If you only change the color, but both colors have the
 * same contrast, your eye must distinguish fore- and background by the
 * color only and this stresses the brain a lot over the time, because it
 * can only use the very small amount of signals it gets from the color
 * receptors, since the breightness receptors won't note a difference.
 * Actually contrast is so much more important than color that you don't
 * have to change the color at all. E.g. light red on dark red reads nicely
 * even though both are the same color, red.

public class FontColorChooser {
    int bred;
    int bgreen;
    int bblue;

    public FontColorChooser(String hexColor) throws NumberFormatException {
        int i;

        i = Integer.parseInt(hexColor, 16);
        bred = (i >> 16);
        bgreen = (i >> 8) & 0xFF;
        bblue = i & 0xFF;

    public static void main(String[] args) {
        FontColorChooser fcc;

        if (args.length == 0) {
            System.out.println("Missing argument!");
                "The first argument must be the background" +
                "color in hex notation."
                "E.g. \"FFFFFF\" for white or \"000000\" for black."
        try {
            fcc = new FontColorChooser(args[0]);
        } catch (Exception e) {
                args[0] + " is no valid hex color!"
        try {
        } catch (IOException e) {
            System.out.println("Failed to write output file!");

    public void start() throws IOException {
        int r;
        int b;
        int g;
        OutputStreamWriter out;

        out = new OutputStreamWriter(
            new FileOutputStream("chosen-font-colors.html"),

        // simple, not W3C comform (most browsers won't care), HTML header
        out.write("</title><style type=\"text/css\">\n");
        out.write("body { background-color:#");
        out.write(rgb2hex(bred, bgreen, bblue));
        out.write("; }\n</style></head>\n<body>\n");

        // try 4096 colors
        for (r = 0; r <= 15; r++) {
            for (g = 0; g <= 15; g++) {
                for (b = 0; b <= 15; b++) {
                    int red;
                    int blue;
                    int green;
                    double cDiff;

                    // brightness increasse like this: 00, 11,22, ..., ff
                    red = (r << 4) | r;
                    blue = (b << 4) | b;
                    green = (g << 4) | g;

                    cDiff = contrastDiff(
                        red, green, blue,
                        bred, bgreen, bblue
                    if (cDiff < 5.0) continue;
                    writeDiv(red, green, blue, out);

        // finalize HTML document


    private void writeDiv(int r, int g, int b, OutputStreamWriter out)
        throws IOException
        String hex;

        hex = rgb2hex(r, g, b);
        out.write("<div style=\"color:#" + hex + "\">");
        out.write("This is a sample text for color " + hex + "</div>\n");

    private double contrastDiff(
        int r1, int g1, int b1, int r2, int g2, int b2
    ) {
        double l1;
        double l2;

        l1 = ( 
            0.2126 * Math.pow((double)r1/255.0, 2.2) +
            0.7152 * Math.pow((double)g1/255.0, 2.2) +
            0.0722 * Math.pow((double)b1/255.0, 2.2) +
        l2 = ( 
            0.2126 * Math.pow((double)r2/255.0, 2.2) +
            0.7152 * Math.pow((double)g2/255.0, 2.2) +
            0.0722 * Math.pow((double)b2/255.0, 2.2) +

        return (l1 > l2) ? (l1 / l2) : (l2 / l1);

    private String rgb2hex(int r, int g, int b) {
        String rs = Integer.toHexString(r);
        String gs = Integer.toHexString(g);
        String bs = Integer.toHexString(b);
        if (rs.length() == 1) rs = "0" + rs;
        if (gs.length() == 1) gs = "0" + gs;
        if (bs.length() == 1) bs = "0" + bs;
        return (rs + gs + bs);

Loop through each cell in a range of cells when given a Range object

To make a note on Dick's answer, this is correct, but I would not recommend using a For Each loop. For Each creates a temporary reference to the COM Cell behind the scenes that you do not have access to (that you would need in order to dispose of it).

See the following for more discussion:

How do I properly clean up Excel interop objects?

To illustrate the issue, try the For Each example, close your application, and look at Task Manager. You should see that an instance of Excel is still running (because all objects were not disposed of properly).

A cleaner way to handle this is to query the spreadsheet using ADO:

How to center the text in PHPExcel merged cell

    /** Error reporting */
    ini_set('display_errors', TRUE);
    ini_set('display_startup_errors', TRUE);

    /** Include PHPExcel */
    require_once '../Classes/PHPExcel.php';

    $objPHPExcel = new PHPExcel();
    $sheet = $objPHPExcel->getActiveSheet();
    $sheet->setCellValueByColumnAndRow(0, 1, "test");
    $objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel2007');

A potentially dangerous Request.Form value was detected from the client

"A potentially dangerous Request.Form value was detected from the client"..

1) set httpRuntime requestValidationMode="2.0" requestPathInvalidCharacters="&lt;,&gt;,\" in web.config file

2) set validateRequest="false" in side pages tag in web.config file

    <httpRuntime requestValidationMode="2.0" requestPathInvalidCharacters="&lt;,&gt;,\"/>
 <pages controlRenderingCompatibilityVersion="3.5" clientIDMode="AutoID" validateRequest="false"/>

Laravel 4: how to "order by" using Eloquent ORM

If you are using post as a model (without dependency injection), you can also do:

$posts = Post::orderBy('id', 'DESC')->get();

Referring to a Column Alias in a WHERE Clause

If you don't want to list all your columns in CTE, another way to do this would be to use outer apply:

    s.logcount, s.logUserID, s.maxlogtm,
from statslogsummary as s
    outer apply (select datediff(day, s.maxlogtm, getdate()) as daysdiff) as a
where a.daysdiff > 120

Calling Python in PHP

Note that if you are using a virtual environment (as in shared hosting) then you must adjust your path to python, e.g: /home/user/mypython/bin/python ./cgi-bin/

Make a link open a new window (not tab)

I know that its bit old Q but if u get here by searching a solution so i got a nice one via jquery

  jQuery('a[target^="_new"]').click(function() {
    var width = window.innerWidth * 0.66 ;
    // define the height in
    var height = width * window.innerHeight / window.innerWidth ;
    // Ratio the hight to the width as the user screen ratio , 'newwindow', 'width=' + width + ', height=' + height + ', top=' + ((window.innerHeight - height) / 2) + ', left=' + ((window.innerWidth - width) / 2));


it will open all the <a target="_new"> in a new window


1st, I did some little changes in the original code now it open the new window perfectly followed the user screen ratio (for landscape desktops)

but, I would like to recommend you to use the following code that open the link in new tab if you in mobile (thanks to zvona answer in other question):

jQuery('a[target^="_new"]').click(function() {
    return openWindow(this.href);

function openWindow(url) {

    if (window.innerWidth <= 640) {
        // if width is smaller then 640px, create a temporary a elm that will open the link in new tab
        var a = document.createElement('a');
        a.setAttribute("href", url);
        a.setAttribute("target", "_blank");

        var dispatch = document.createEvent("HTMLEvents");
        dispatch.initEvent("click", true, true);

    else {
        var width = window.innerWidth * 0.66 ;
        // define the height in
        var height = width * window.innerHeight / window.innerWidth ;
        // Ratio the hight to the width as the user screen ratio , 'newwindow', 'width=' + width + ', height=' + height + ', top=' + ((window.innerHeight - height) / 2) + ', left=' + ((window.innerWidth - width) / 2));
    return false;

Adding attribute in jQuery

Add attribute as:


How do I get the SQLSRV extension to work with PHP, since MSSQL is deprecated?

Download Microsoft Drivers for PHP for SQL Server. Extract the files and use one of:

File                             Thread Safe         VC Bulid
php_sqlsrv_53_nts_vc6.dll           No                  VC6
php_sqlsrv_53_nts_vc9.dll           No                  VC9
php_sqlsrv_53_ts_vc6.dll            Yes                 VC6
php_sqlsrv_53_ts_vc9.dll            Yes                 VC9

You can see the Thread Safety status in phpinfo().

Add the correct file to your ext directory and the following line to your php.ini:


Use the filename of the file you used.

As Gordon already posted this is the new Extension from Microsoft and uses the sqlsrv_* API instead of mssql_*

On Linux you do not have the requisite drivers and neither the SQLSERV Extension.
Look at Connect to MS SQL Server from PHP on Linux? for a discussion on this.

In short you need to install FreeTDS and YES you need to use mssql_* functions on linux. see update 2

To simplify things in the long run I would recommend creating a wrapper class with requisite functions which use the appropriate API (sqlsrv_* or mssql_*) based on which extension is loaded.

Update 2: You do not need to use mssql_* functions on linux. You can connect to an ms sql server using PDO + ODBC + FreeTDS. On windows, the best performing method to connect is via PDO + ODBC + SQL Native Client since the PDO + SQLSRV driver can be incredibly slow.

What is the correct way to free memory in C#

Let's answer your questions one by one.

  1. Yes, you make a new object whenever this statement is executed, however, it goes "out of scope" when you exit the method and it is eligible for garbage collection.
  2. Well this would be the same as #1, except that you've used a string type. A string type is immutable and you get a new object every time you make an assignment.
  3. Yes the garbage collector collects the out of scope objects, unless you assign the object to a variable with a large scope such as class variable.
  4. Yes.
  5. The using statement only applies to objects that implement the IDisposable interface. If that is the case, by all means using is best for objects within a method's scope. Don't put Foo o at a larger scope unless you have a good reason to do so. It is best to limit the scope of any variable to the smallest scope that makes sense.

Unable to copy a file from obj\Debug to bin\Debug

Rename the assembly to a different name to solve this issue.

I get a "An attempt was made to load a program with an incorrect format" error on a SQL Server replication project

Change the value for Platform Target on your web project's property page to Any CPU.

enter image description here

Importing CSV File to Google Maps

We have now (jan2017) a csv layer import inside Google Maps itself.enter image description here

Google Maps > "Your Places" > "Open in My Maps"

REST API - Use the "Accept: application/json" HTTP Header

Basically I use Fiddler or Postman for testing API's.

In fiddler, in request header you need to specify instead of xml, html you need to change it to json. Eg: Accept: application/json. That should do the job.

Retrieving parameters from a URL

There is a new library called furl. I find this library to be most pythonic for doing url algebra. To install:

pip install furl


from furl import furl
f = furl("/abc?def='ghi'") 
print f.args['def']

SQL Server Configuration Manager not found

This path worked for me. on a 32 bit machine.

C:\Windows\System32\mmc.exe /32 C:\Windows\system32\SQLServerManager10.msc

What is the current choice for doing RPC in Python?

Since I've asked this question, I've started using python-symmetric-jsonrpc. It is quite good, can be used between python and non-python software and follow the JSON-RPC standard. But it lacks some examples.

Coarse-grained vs fine-grained

Coarse-grained granularity does not always mean bigger components, if you go by literally meaning of the word coarse, it means harsh, or not appropriate. e.g. In software projects management, if you breakdown a small system into few components, which are equal in size, but varies in complexities and features, this could lead to a coarse-grained granularity. In reverse, for a fine-grained breakdown, you would divide the components based on their cohesiveness of the functionalities each component is providing.

Characters allowed in GET parameter

"." | "!" | "~" | "*" | "'" | "(" | ")" are also acceptable [RFC2396]. Really, anything can be in a GET parameter if it is properly encoded.

Is there any option to limit mongodb memory usage?

This question has been asked a couple times ...

See this related question/answer (quoted below) ... how to release the caching which is used by Mongodb?

MongoDB will (at least seem) to use up a lot of available memory, but it actually leaves it up to the OS's VMM to tell it to release the memory (see Caching in the MongoDB docs.)

You should be able to release any and all memory by restarting MongoDB.

However, to some extent MongoDB isn't really "using" the memory.

For example from the MongoDB docs Checking Server Memory Usage ...

Depending on the platform you may see the mapped files as memory in the process, but this is not strictly correct. Unix top may show way more memory for mongod than is really appropriate. The Operating System (the virtual memory manager specifically, depending on OS) manages the memory where the "Memory Mapped Files" reside. This number is usually shown in a program like "free -lmt".

It is called "cached" memory.

MongoDB uses the LRU (Least Recently Used) cache algorithm to determine which "pages" to release, you will find some more information in these two questions ...

REST response code for invalid data

I would recommend 422. It's not part of the main HTTP spec, but it is defined by a public standard (WebDAV) and it should be treated by browsers the same as any other 4xx status code.

From RFC 4918:

The 422 (Unprocessable Entity) status code means the server understands the content type of the request entity (hence a 415(Unsupported Media Type) status code is inappropriate), and the syntax of the request entity is correct (thus a 400 (Bad Request) status code is inappropriate) but was unable to process the contained instructions. For example, this error condition may occur if an XML request body contains well-formed (i.e., syntactically correct), but semantically erroneous, XML instructions.

Checking if my Windows application is running

I really simplistic way I guess would be, for every exe that is running, you could create/open a file on disk in a known location (c:\temp) with a special name "yourapp.lock" and then just count how many of those there are.

A harder way, would be to open up some inter-process communication, or sockets, so with the process list you could interrogate each process to see if it was your application.

MVC 5 Access Claims Identity User Data

You can also do this.

IEnumerable<Claim> claims = ClaimsPrincipal.Current.Claims;

Show spinner GIF during an $http request in AngularJS?

.factory('authHttpResponseInterceptor', ['$q', function ($q) {
        return {
            request: function(config) {
                return config;
            response : function(response) {
                return response || $q.when(response);
            responseError: function(reason) {
                return $q.reject(reason);

 .config(['$routeProvider', '$locationProvider', '$translateProvider', '$httpProvider',
            function ($routeProvider, $locationProvider, $translateProvider, $httpProvider) {

in your Template
<div id="spinner"></div>


#spinner:after {
  border-radius: 50%;
  width: 10em;
  height: 10em;
  background-color: #A9A9A9;
  z-index: 10000;
  position: absolute;
  left: 50%;
  bottom: 100px;
@-webkit-keyframes load8 {
  0% {
    -webkit-transform: rotate(0deg);
    transform: rotate(0deg);
  100% {
    -webkit-transform: rotate(360deg);
    transform: rotate(360deg);
@keyframes load8 {
  0% {
    -webkit-transform: rotate(0deg);
    transform: rotate(0deg);
  100% {
    -webkit-transform: rotate(360deg);
    transform: rotate(360deg);

How to increment a pointer address and pointer's value?

        1) Both ++ and * have same precedence(priority), so the associativity comes into picture.
        2) in this case Associativity is from **Right-Left**

        important table to remember in case of pointers and arrays: 

        operators           precedence        associativity

    1)  () , []                1               left-right
    2)  *  , identifier        2               right-left
    3)  <data type>            3               ----------

        let me give an example, this might help;

        char **str;
        str = (char **)malloc(sizeof(char*)*2); // allocate mem for 2 char*
        str[0]=(char *)malloc(sizeof(char)*10); // allocate mem for 10 char
        str[1]=(char *)malloc(sizeof(char)*10); // allocate mem for 10 char

        strcpy(str[0],"abcd");  // assigning value
        strcpy(str[1],"efgh");  // assigning value

            cout<<*str<<endl;   // printing the string
            *str++;             // incrementing the address(pointer)
                                // check above about the prcedence and associativity

Android Studio update -Error:Could not run build action using Gradle distribution

I had the same problem and I Just Invalidate caches/restart

C# : Out of Memory exception

My Development Team resolved this situation:

We added the following Post-Build script into the .exe project and compiled again, setting the target to x86 and increasing by 1.5 gb and also x64 Platform target increasing memory using 3.2 gb. Our application is 32 bit.

Related URLs:


if exist "$(DevEnvDir)..\tools\vsvars32.bat" (
    call "$(DevEnvDir)..\tools\vsvars32.bat"
    editbin /largeaddressaware "$(TargetPath)"

Getting an element from a Set

Following can be an approach

   SharedPreferences se_get = getSharedPreferences("points",MODE_PRIVATE);
   Set<String> main = se_get.getStringSet("mydata",null);
   for(int jk = 0 ; jk < main.size();jk++)

Get: TypeError: 'dict_values' object does not support indexing when using python 3.2.3

In Python 3 the dict.values() method returns a dictionary view object, not a list like it does in Python 2. Dictionary views have a length, can be iterated, and support membership testing, but don't support indexing.

To make your code work in both versions, you could use either of these:

{names[i]:value for i,value in enumerate(d.values())}


values = list(d.values())
{name:values[i] for i,name in enumerate(names)}

By far the simplest, fastest way to do the same thing in either version would be:

dict(zip(names, d.values()))

Note however, that all of these methods will give you results that will vary depending on the actual contents of d. To overcome that, you may be able use an OrderedDict instead, which remembers the order that keys were first inserted into it, so you can count on the order of what is returned by the values() method.


Bear in mind that the GoogleFinance() function isn't working 100% in the new version of Google Sheets. For example, converting from USD to GBP using the formula GoogleFinance("CURRENCY:USDGBP") gives 0.603974 in the old version, but only 0.6 in the new one. Looks like there's a rounding error.

"X-UA-Compatible" content="IE=9; IE=8; IE=7; IE=EDGE"

If you support IE, for versions of Internet Explorer 8 and above, this:

<meta http-equiv="X-UA-Compatible" content="IE=9; IE=8; IE=7" />

Forces the browser to render as that particular version's standards. It is not supported for IE7 and below.

If you separate with semi-colon, it sets compatibility levels for different versions. For example:

<meta http-equiv="X-UA-Compatible" content="IE=7; IE=9" />

Renders IE7 and IE8 as IE7, but IE9 as IE9. It allows for different levels of backwards compatibility. In real life, though, you should only chose one of the options:

<meta http-equiv="X-UA-Compatible" content="IE=8" />

This allows for much easier testing and maintenance. Although generally the more useful version of this is using Emulate:

<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE8" />

For this:

<meta http-equiv="X-UA-Compatible" content="IE=Edge" />

It forces the browser the render at whatever the most recent version's standards are.

For more information, there is plenty to read about on MSDN,

C++ wait for user input

Several ways to do so, here are some possible one-line approaches:

  1. Use getch() (need #include <conio.h>).

  2. Use getchar() (expected for Enter, need #include <iostream>).

  3. Use cin.get() (expected for Enter, need #include <iostream>).

  4. Use system("pause") (need #include <iostream>).

    PS: This method will also print Press any key to continue . . . on the screen. (seems perfect choice for you :))

Edit: As discussed here, There is no completely portable solution for this. Question 19.1 of the comp.lang.c FAQ covers this in some depth, with solutions for Windows, Unix-like systems, and even MS-DOS and VMS.

ANTLR: Is there a simple example?

At you'll find an ANTLR java library with some useful helper classes and a few complete examples. It's ready to be used with maven and if you like eclipse and maven.

is a simple Expression language that can do multiply and add operations. has the corresponding unit tests for it. is an IRI parser that has been split into the three parts:

  1. parser grammar
  2. lexer grammar
  3. imported LexBasic grammar has the unit tests for it.

Personally I found this the most tricky part to get right. See

contains three more examples that have been created for a performance issue of ANTLR4 in an earlier version. In the meantime this issues has been fixed as the testcase shows.

Git adding files to repo

my problem (git on macOS) was solved by using sudo git instead of just git in all add and commit commands

What is the difference between `throw new Error` and `throw someObject`?

The following article perhaps goes into some more detail as to which is a better choice; throw 'An error' or throw new Error('An error'):

It suggests that the latter (new Error()) is more reliable, since browsers like Internet Explorer and Safari (unsure of versions) don't correctly report the message when using the former.

Doing so will cause an error to be thrown, but not all browsers respond the way you’d expect. Firefox, Opera, and Chrome each display an “uncaught exception” message and then include the message string. Safari and Internet Explorer simply throw an “uncaught exception” error and don’t provide the message string at all. Clearly, this is suboptimal from a debugging point of view.

LDAP server which is my base dn

Either you set LDAP_DOMAIN variable or you misconfigured it. Jump inside of ldap machine/container and run:

slapcat > backup.ldif

If it fails, check punctuation, quotes etc while you assigned variable "LDAP_DOMAIN" Otherwise you will find answer inside on backup.ldif file.

Changing button text onclick

There are lots of ways. And this should work too in all browsers and you don't have to use document.getElementById anymore since you're passing the element itself to the function.

<input type="button" value="Open Curtain" onclick="return change(this);" />

<script type="text/javascript">
function change( el )
    if ( el.value === "Open Curtain" )
        el.value = "Close Curtain";
        el.value = "Open Curtain";

Prevent screen rotation on Android

The easiest way I found to do this was to put


within onCreate, just after



protected void onCreate(Bundle savedInstanceState) {

Visual Studio can't 'see' my included header files

I encountered this issue, but the solutions provided didn't directly help me, so I'm sharing how I got myself into a similar situation and temporarily resolved it.

I created a new project within an existing solution and copy & pasted the Header and CPP file from another project within that solution that I needed to include in my new project through the IDE. Intellisense displayed an error suggesting it could not resolve the reference to the header file and compiling the code failed with the same error too.

After reading the posts here, I checked the project folder with Windows File Explorer and only the main.cpp file was found. For some reason, my copy and paste of the header file and CPP file were just a reference? (I assume) and did not physically copy the file into the new project file.

I deleted the files from the Project view within Visual Studio and I used File Explorer to copy the files that I needed to the project folder/directory. I then referenced the other solutions posted here to "include files in project" by showing all files and this resolved the problem.

It boiled down to the files not being physically in the Project folder/directory even though they were shown correctly within the IDE.

Please Note I understand duplicating code is not best practice and my situation is purely a learning/hobby project. It's probably in my best interest and anyone else who ended up in a similar situation to use the IDE/project/Solution setup correctly when reusing code from other projects - I'm still learning and I'll figure this out one day!

Get list from pandas dataframe column or row?

Example conversion:

Numpy Array -> Panda Data Frame -> List from one Panda Column

Numpy Array

data = np.array([[10,20,30], [20,30,60], [30,60,90]])

Convert numpy array into Panda data frame

dataPd = pd.DataFrame(data = data)
0   1   2
0  10  20  30
1  20  30  60
2  30  60  90

Convert one Panda column to list

pdToList = list(dataPd['2'])

Select and trigger click event of a radio button in jquery

In my case i had to load images on radio button click, I just uses the regular onclick event and it worked for me.

 <input type="radio" name="colors" value="{{}}" id="{{}}-option" class="color_radion"  onclick="return get_images(this, {{}})">

  function get_images(obj, color){


Why this line xmlns:android="" must be the first in the layout xml file?

xmlns:android This is start tag for define android namespace in Android. This is standerd convention define by android google developer. when you are using and layout default or custom, then must use this namespace.

Defines the Android namespace. This attribute should always be set to "".

From the <manifest> element documentation.

What is the difference between URI, URL and URN?

URI (Uniform Resource Identifier) according to Wikipedia:

a string of characters used to identify a resource.

URL (Uniform Resource Locator) is a URI that implies an interaction mechanism with resource. for example specifies the use of HTTP as the interaction mechanism. Not all URIs need to convey interaction-specific information.

URN (Uniform Resource Name) is a specific form of URI that has urn as it's scheme. For more information about the general form of a URI refer to

IRI (International Resource Identifier) is a revision to the definition of URI that allows us to use international characters in URIs.

jsonify a SQLAlchemy result set in Flask

Here's my answer if you're using the declarative base (with help from some of the answers already posted):

# in your models definition where you define and extend declarative_base()
from sqlalchemy.ext.declarative import declarative_base
Base = declarative_base()
Base.query = db_session.query_property()

# define a new class (call "Model" or whatever) with an as_dict() method defined
class Model():
    def as_dict(self):
        return { getattr(self, for c in self.__table__.columns }

# and extend both the Base and Model class in your model definition, e.g.
class Rating(Base, Model):
    ____tablename__ = 'rating'
    id = db.Column(db.Integer, primary_key=True)
    fullurl = db.Column(db.String())
    url = db.Column(db.String())
    comments = db.Column(db.Text)

# then after you query and have a resultset (rs) of ratings
rs = Rating.query.all()

# you can jsonify it with
s = json.dumps([r.as_dict() for r in rs], default=alchemyencoder)
print (s)

# or if you have a single row
r = Rating.query.first()

# you can jsonify it with
s = json.dumps(r.as_dict(), default=alchemyencoder)

# you will need this alchemyencoder where your are calling json.dumps to handle datetime and decimal format
# credit to Joonas @
def alchemyencoder(obj):
    """JSON encoder function for SQLAlchemy special classes."""
    if isinstance(obj,
        return obj.isoformat()
    elif isinstance(obj, decimal.Decimal):
        return float(obj)

Explain the "setUp" and "tearDown" Python methods used in test cases

You can use these to factor out code common to all tests in the test suite.

If you have a lot of repeated code in your tests, you can make them shorter by moving this code to setUp/tearDown.

You might use this for creating test data (e.g. setting up fakes/mocks), or stubbing out functions with fakes.

If you're doing integration testing, you can use check environmental pre-conditions in setUp, and skip the test if something isn't set up properly.

For example:

class TurretTest(unittest.TestCase):

    def setUp(self):
        self.turret_factory = TurretFactory()
        self.turret = self.turret_factory.CreateTurret()

    def test_turret_is_on_by_default(self):
        self.assertEquals(True, self.turret.is_on())

    def test_turret_turns_can_be_turned_off(self):
        self.assertEquals(False, self.turret.is_on())

how to remove the dotted line around the clicked a element in html

Its simple try below code --

outline: medium none !important;

If happy cheers! Good day

Java: unable to find valid certification path to requested target

Make sure that the have a valid certificate. you can check it via browser firstly https not secure if it works in browser it will work in java.

that is working for me

Bulk insert with SQLAlchemy ORM

Direct support was added to SQLAlchemy as of version 0.8

As per the docs, connection.execute(table.insert().values(data)) should do the trick. (Note that this is not the same as connection.execute(table.insert(), data) which results in many individual row inserts via a call to executemany). On anything but a local connection the difference in performance can be enormous.

Entity Framework - Include Multiple Levels of Properties

I'm going to add my solution to my particular problem. I had two collections at the same level I needed to include. The final solution looked like this.

var recipe = _bartendoContext.Recipes
    .Include(r => r.Ingredients)
    .ThenInclude(r => r.Ingredient)
    .Include(r => r.Ingredients)
    .ThenInclude(r => r.MeasurementQuantity)
    .FirstOrDefault(r => r.Id == recipeId);
if (recipe?.Ingredients == null) return 0m;
var abv = recipe.Ingredients.Sum(ingredient => ingredient.Ingredient.AlcoholByVolume * ingredient.MeasurementQuantity.Quantity);
return abv;

This is calculating the percent alcohol by volume of a given drink recipe. As you can see I just included the ingredients collection twice then included the ingredient and quantity onto that.

Removing the textarea border in HTML

This one is great:

<style type="text/css">
width: 100%;
height: 100%;
border-color: Transparent;     
<textarea class="test"></textarea>

How can I solve Exception in thread "main" java.lang.NullPointerException error

This is the problem

double a[] = null;

Since a is null, NullPointerException will arise every time you use it until you initialize it. So this:

a[i] = var;

will fail.

A possible solution would be initialize it when declaring it:

double a[] = new double[PUT_A_LENGTH_HERE]; //seems like this constant should be 7

IMO more important than solving this exception, is the fact that you should learn to read the stacktrace and understand what it says, so you could detect the problems and solve it.


This exception means there's a variable with null value being used. How to solve? Just make sure the variable is not null before being used.

at twoten.TwoTenB.(

This line has two parts:

  • First, shows the class and method where the error was thrown. In this case, it was at <init> method in class TwoTenB declared in package twoten. When you encounter an error message with SomeClassName.<init>, means the error was thrown while creating a new instance of the class e.g. executing the constructor (in this case that seems to be the problem).
  • Secondly, shows the file and line number location where the error is thrown, which is between parenthesis. This way is easier to spot where the error arose. So you have to look into file, line number 29. This seems to be a[i] = var;.

From this line, other lines will be similar to tell you where the error arose. So when reading this:

at javapractice.JavaPractice.main(

It means that you were trying to instantiate a TwoTenB object reference inside the main method of your class JavaPractice declared in javapractice package.

Iteration over std::vector: unsigned vs signed index variable

Consider whether you need to iterate at all

The <algorithm> standard header provides us with facilities for this:

using std::begin;  // allows argument-dependent lookup even
using std::end;    // if the container type is unknown here
auto sum = std::accumulate(begin(polygon), end(polygon), 0);

Other functions in the algorithm library perform common tasks - make sure you know what's available if you want to save yourself effort.

Laravel Soft Delete posts

Updated Version (Version 5.0 & Later):

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;

class Post extends Model {

    use SoftDeletes;

    protected $table = 'posts';

    // ...

When soft deleting a model, it is not actually removed from your database. Instead, a deleted_at timestamp is set on the record. To enable soft deletes for a model, specify the softDelete property on the model (Documentation).

For (Version 4.2):

use Illuminate\Database\Eloquent\SoftDeletingTrait; // <-- This is required

class Post extends Eloquent {

    use SoftDeletingTrait;

    protected $table = 'posts';

    // ...

Prior to Version 4.2 (But not 4.2 & Later)

For example (Using a posts table and Post model):

class Post extends Eloquent {

    protected $table = 'posts';
    protected $softDelete = true;
    // ...

To add a deleted_at column to your table, you may use the softDeletes method from a migration:

For example (Migration class' up method for posts table) :

 * Run the migrations.
 * @return void
public function up()
    Schema::create('posts', function(Blueprint $table)
        // more fields
        $table->softDeletes(); // <-- This will add a deleted_at field

Now, when you call the delete method on the model, the deleted_at column will be set to the current timestamp. When querying a model that uses soft deletes, the "deleted" models will not be included in query results. To soft delete a model you may use:

$model = Contents::find( $id );

Deleted (soft) models are identified by the timestamp and if deleted_at field is NULL then it's not deleted and using the restore method actually makes the deleted_at field NULL. To permanently delete a model you may use forceDelete method.

How can I convert this foreach code to Parallel.ForEach?

string[] lines = File.ReadAllLines(txtProxyListPath.Text);

// No need for the list
// List<string> list_lines = new List<string>(lines); 

Parallel.ForEach(lines, line =>
    //My Stuff

This will cause the lines to be parsed in parallel, within the loop. If you want a more detailed, less "reference oriented" introduction to the Parallel class, I wrote a series on the TPL which includes a section on Parallel.ForEach.

Add carriage return to a string

Environment.NewLine should be used as Dan Rigby said but there is one problem with the String.Empty. It will remain always empty no matter if it is read before or after it reads. I had a problem in my project yesterday with that. I removed it and it worked the way it was supposed to. It's better to declare the variable and then call it when it's needed. String.Empty will always keep it empty unless the variable needs to be initialized which only then should you use String.Empty. Thought I would throw this tid-bit out for everyone as I've experienced it.

git replace local version with remote version

This is the safest solution:

git stash

Now you can do whatever you want without fear of conflicts.

For instance:

git checkout origin/master

If you want to include the remote changes in the master branch you can do:

git reset --hard origin/master

This will make you branch "master" to point to "origin/master".

How to indent/format a selection of code in Visual Studio Code with Ctrl + Shift + F

I want to indent a specific section of code in Visual Studio Code:

  • Select the lines you want to indent, and
  • use Ctrl + ] to indent them.

If you want to format a section (instead of indent it):

  • Select the lines you want to format,
  • use Ctrl + K, Ctrl + F to format them.

Closing database connections in Java

Yes. You need to close the resultset, the statement and the connection. If the connection has come from a pool, closing it actually sends it back to the pool for reuse.

You typically have to do this in a finally{} block, such that if an exception is thrown, you still get the chance to close this.

Many frameworks will look after this resource allocation/deallocation issue for you. e.g. Spring's JdbcTemplate. Apache DbUtils has methods to look after closing the resultset/statement/connection whether null or not (and catching exceptions upon closing), which may also help.

Google Map API - Removing Markers

Following code might be useful if someone is using React and has a different component of Marker and want to remove marker from map.

export default function useGoogleMapMarker(props) {
  const [marker, setMarker] = useState();

  useEffect(() => {
    // ...code
    const marker = new maps.Marker({ position, map, title, icon });
    // ...code
    return () => marker.setMap(null); // to remove markers when unmounts
  }, []);

  return marker;

What is 'Context' on Android?

  • Context represents a handle to get environment data .
  • Context class itself is declared as abstract, whose implementation is provided by the android OS.
  • Context is like remote of a TV & channel's in the television are resources, services, etc. enter image description here

What can you do with it ?

  • Loading resource.
  • Launching a new activity.
  • Creating views.
  • Obtaining system service.

Ways to get context :

  • getApplicationContext()
  • getContext()
  • getBaseContext()enter image description hereenter image description here

Convert special characters to HTML in Javascript

The best way in my opinion is to use the browser's inbuilt HTML escape functionality to handle many of the cases. To do this simply create a element in the DOM tree and set the innerText of the element to your string. Then retrieve the innerHTML of the element. The browser will return an HTML encoded string.

function HtmlEncode(s)
  var el = document.createElement("div");
  el.innerText = el.textContent = s;
  s = el.innerHTML;
  return s;

Test run:




This method of escaping HTML is also used by the Prototype JS library though differently from the simplistic sample I have given.

Note: You will still need to escape quotes (double and single) yourself. You can use any of the methods outlined by others here.

What is the most efficient way to create HTML elements using jQuery?

This is not the correct answer for the question but still I would like to share this...

Using just document.createElement('div') and skipping JQuery will improve the performance a lot when you want to make lot of elements on the fly and append to DOM.

How to execute XPath one-liners from shell?

It bears mentioning that nokogiri itself ships with a command line tool, which should be installed with gem install nokogiri.

You might find this blog post useful.

How to open spss data files in excel?

In order to download that driver you must have a license to SPSS. For those who do not, there is an open source tool that is very much like SPSS and will allow you to import SAV files and export them to CSV.

Here's the software

And here are the steps to export the data.

Trying to load local JSON file to show data in a html page using JQuery


$("button").click( function() {
 $.getJSON( "article.json", function(obj) {
  $.each(obj, function(key, value) {
         $("ul").append("<li>""'s age is : "+value.age+"</li>");


<!DOCTYPE html>
    <meta charset="utf-8">
    <title>Tax Calulator</title>
    <script src="jquery-3.2.0.min.js" type="text/javascript"></script>
<script type="text/javascript" src="app.js"></script>


"a": {
"name": "Abra",
"age": 125,
"company": "Dabra"
"b": {
"name": "Tudak tudak",
"age": 228,
"company": "Dhidak dhidak"


var http = require('http');
var fs = require('fs');

function onRequest(request,response){
  if(request.method == 'GET' && request.url == '/') {
  } else if(request.method == 'GET' && request.url == '/jquery-3.2.0.min.js') {
  } else if(request.method == 'GET' && request.url == '/app.js') {
  else if(request.method == 'GET' && request.url == '/article.json') {

console.log("Server is running ....");

Server.js will run a simple node http server in your local to process the data.

Note don't forget toa dd jQuery library in your folder structure and change the version number accordingly in server.js and index.html

This is my running one

Creating a new user and password with Ansible

Generating random password for user

first need to define users variable then follow below


- name: Generate Passwords
  become: no
  local_action: command pwgen -N 1 8
  with_items: '{{ users }}'
  register: user_passwords

- name: Update User Passwords
    name: '{{ item.item }}'
    password: "{{ item.stdout | password_hash('sha512')}}"
    update_password: on_create
  with_items: '{{ user_passwords.results }}'

- name: Save Passwords Locally
  become: no
  local_action: copy content={{ item.stdout }} dest=./{{ item.item }}.txt
  with_items: '{{ user_passwords.results }}'

Jquery click event not working after append method


As of jQuery version 1.7+, the on() method is the new replacement for the bind(), live() and delegate() methods.


$(document).on("click", "a.new_participant_form" , function() {

Or for more information CHECK HERE

Eclipse : Maven search dependencies doesn't work

For me for this issue worked to:

  • remove ~/.m2
  • enable "Full Index Enabled" in maven repository view on central repository
  • "Rebuild Index" on central maven repository

After eclipse restart everything worked well.

How to connect to MySQL Database?

Looking at the code below, I tried it and found: Instead of writing DBCon = DBConnection.Instance(); you should put DBConnection DBCon - new DBConnection(); (That worked for me)

and instead of MySqlComman cmd = new MySqlComman(query, DBCon.GetConnection()); you should put MySqlCommand cmd = new MySqlCommand(query, DBCon.GetConnection()); (it's missing the d)

How to fix the Eclipse executable launcher was unable to locate its companion shared library for windows 7?

Had similar issue, which was a result of update. Please make sure that names of libraries mentioned in eclipse.ini and the actual names of these files on your disk match exactly.



Here is the post that I used to fix this issue on my system

How do I use a compound drawable instead of a LinearLayout that contains an ImageView and a TextView

You can use general compound drawable implementation, but if you need to define a size of drawable use this library:

Here is a small example of usage:

        android:text="Some text"
        app:compoundDrawableWidth="24dp" />

MySQL CONCAT returns NULL if any field contain NULL

To have the same flexibility in CONCAT_WS as in CONCAT (if you don't want the same separator between every member for instance) use the following:

SELECT CONCAT_WS("",affiliate_name,':',model,'-',ip,... etc)

What is the difference between buffer and cache memory in Linux?

Buffer is an area of memory used to temporarily store data while it's being moved from one place to another.

Cache is a temporary storage area used to store frequently accessed data for rapid access. Once the data is stored in the cache, future use can be done by accessing the cached copy rather than re-fetching the original data, so that the average access time is shorter.

Note: buffer and cache can be allocated on disk as well

UILabel with text of two different colors

Swift 4 and above: Inspired by anoop4real's solution, here's a String extension that can be used to generate text with 2 different colors.

extension String {

    func attributedStringForPartiallyColoredText(_ textToFind: String, with color: UIColor) -> NSMutableAttributedString {
        let mutableAttributedstring = NSMutableAttributedString(string: self)
        let range = mutableAttributedstring.mutableString.range(of: textToFind, options: .caseInsensitive)
        if range.location != NSNotFound {
            mutableAttributedstring.addAttribute(NSAttributedStringKey.foregroundColor, value: color, range: range)
        return mutableAttributedstring

Following example changes color of asterisk to red while retaining original label color for remaining text.

label.attributedText = "Enter username *".attributedStringForPartiallyColoredText("*", with: #colorLiteral(red: 1, green: 0, blue: 0, alpha: 1))

Does a `+` in a URL scheme/host/path represent a space?

use encodeURIComponent function to fix url, it works on Browser and node.js

res.redirect("/signin?email="+encodeURIComponent("[email protected]"));

> encodeURIComponent("")

PostgreSQL: export resulting data from SQL query to Excel/CSV

In PostgreSQL 9.4 to create to file CSV with the header in Ubuntu:

COPY (SELECT * FROM tbl) TO '/home/user/Desktop/result_sql.csv' WITH CSV HEADER;

Note: The folder must be writable.

JSON response parsing in Javascript to get key/value pair

Try the JSON Parser by Douglas Crockford at github. You can then simply create a JSON object out of your String variable as shown below:

var JSONText = '{"c":{"a":[{"name":"cable - black","value":2},{"name":"case","value":2}]},"o":{"v":[{"name":"over the ear headphones - white/purple","value":1}]},"l":{"e":[{"name":"lens cleaner","value":1}]},"h":{"d":[{"name":"hdmi cable","value":1},{"name":"hdtv essentials (hdtv cable setup)","value":1},{"name":"hd dvd \u0026 blue-ray disc lens cleaner","value":1}]}'

var JSONObject = JSON.parse(JSONText);
var c = JSONObject["c"];
var o = JSONObject["o"];

How exactly does the python any() function work?

It's because the iterable is

(x > 0 for x in list)

Note that x > 0 returns either True or False and thus you have an iterable of booleans.

How to detect if CMD is running as Administrator/has elevated privileges?

If you are running as a user with administrator rights then environment variable SessionName will NOT be defined and you still don't have administrator rights when running a batch file.

You should use "net session" command and look for an error return code of "0" to verify administrator rights.

Example; - the first echo statement is the bell character net session >nul 2>&1 if not %errorlevel%==0 (echo echo You need to start over and right-click on this file, echo then select "Run as administrator" to be successfull. echo.&pause&exit)

Get the current URL with JavaScript?

Open Developer Tools, type in the following in the console and press Enter.


Ex: Below is the screenshot of the result on the current page.

enter image description here

Grab what you need from here. :)

How can I change the user on Git Bash?

If you want to change the user at git Bash .You just need to configure particular user and email(globally) at the git bash.

$ git config --global "abhi"
$ git config --global "[email protected]"

Note: No need to delete the user from Keychain .

Input widths on Bootstrap 3

You don't have to give up simple css :)

.short { max-width: 300px; }
<input type="text" class="form-control short" id="...">