Programs & Examples On #Trinidad

Trinidad is a JSF component library. It is a subproject of Apache MyFaces. The codebase was born as Oracle ADF Faces and was later donated to Apache by Oracle. The codebase is of high quality and supports features as partial page rendering (ajax), integrated clientside validation, Section 508 accessibility, LTR languages, etc.

How to avoid variable substitution in Oracle SQL Developer with 'trinidad & tobago'

this will work as you asked without CHAR(38):

update t set country = 'Trinidad and Tobago' where country = 'trinidad & '|| 'tobago';

create table table99(col1 varchar(40));
insert into table99 values('Trinidad &' || '  Tobago');
insert into table99 values('Trinidad &' || '  Tobago');
insert into table99 values('Trinidad &' || '  Tobago');
insert into table99 values('Trinidad &' || '  Tobago');
SELECT * FROM table99;

update table99 set col1 = 'Trinidad and Tobago' where col1 = 'Trinidad &'||'  Tobago';

Default nginx client_max_body_size

You can increase body size in nginx configuration file as

sudo nano /etc/nginx/nginx.conf

client_max_body_size 100M;

Restart nginx to apply the changes.

sudo service nginx restart

SSIS how to set connection string dynamically from a config file

Here's some background on the mechanism you should use, called Package Configurations: Understanding Integration Services Package Configurations. The article describes 5 types of configurations:

  • XML configuration file
  • Environment variable
  • Registry entry
  • Parent package variable
  • SQL Server

Here's a walkthrough of setting up a configuration on a Connection Manager: SQL Server Integration Services SSIS Package Configuration - I do realize this is using an environment variable for the connection string (not a great idea), but the basics are identical to using an XML file. The only step(s) you have to change in that walkthrough are the configuration type, and then a path.

How do you read scanf until EOF in C?

Scanf is pretty much always more trouble than it's worth. Here are two better ways to do what you're trying to do. This first one is a more-or-less direct translation of your code. It's longer, but you can look at it and see clearly what it does, unlike with scanf.

#include <stdio.h>
#include <ctype.h>
int main(void)
    char buf[1024], *p, *q;
    while (fgets(buf, 1024, stdin))
        p = buf;
        while (*p)
            while (*p && isspace(*p)) p++;
            q = p;
            while (*q && !isspace(*q)) q++;
            *q = '\0';
            if (p != q)
            p = q;
    return 0;

And here's another version. It's a little harder to see what this does by inspection, but it does not break if a line is longer than 1024 characters, so it's the code I would use in production. (Well, really what I would use in production is tr -s '[:space:]' '\n', but this is how you implement something like that.)

#include <stdio.h>
#include <ctype.h>
int main(void)
    int ch, lastch = '\0';
    while ((ch = getchar()) != EOF)
        if (!isspace(ch))
        if (!isspace(lastch))
        lastch = ch;
    if (lastch != '\0' && !isspace(lastch))
    return 0;

adb command not found in linux environment

For Fedora

sudo dnf install adb 

SQL command to display history of queries

You can look at the query cache: but it might not give you access to the actual queries and will be very hit-and-miss if it did work (subtle pun intended)

But MySQL Query Browser very likely maintains its own list of queries that it runs, outside of the MySQL engine. You would have to do the same in your app.

Edit: see dan m's comment leading to this: How to show the last queries executed on MySQL? looks sound.

Is there a method that tells my program to quit?

In Python 3 there is an exit() function:

elif choice == "q":

Java web start - Unable to load resource

Try using Janela or github to diagnose the problem.

What is the difference between Release and Debug modes in Visual Studio?

Well, it depends on what language you are using, but in general they are 2 separate configurations, each with its own settings. By default, Debug includes debug information in the compiled files (allowing easy debugging) while Release usually has optimizations enabled.

As far as conditional compilation goes, they each define different symbols that can be checked in your program, but they are language-specific macros.

How to get current working directory in Java?

If you want to get your current working directory then use the following line

System.out.println(new File("").getAbsolutePath());

Using ng-click vs bind within link function of Angular Directive

In this case, no need for a directive. This does the job :

<button ng-click="count = count + 1" ng-init="count=0">
  count: {{count}}


How to perform an SQLite query within an Android application?

Try this, this works for my code name is a String:

cursor = rdb.query(true, TABLE_PROFILE, new String[] { ID,
    ROLEID, NATIONALID, URL, IMAGEURL },                    
    LASTNAME + " like ?", new String[]{ name+"%" }, null, null, null, null);

How to show an empty view with a RecyclerView?

Use AdapterDataObserver in custom RecyclerView



enum class RecyclerViewEnum {


class RecyclerViewEmptyLoadingSupport : RecyclerView {

    var stateView: RecyclerViewEnum? = RecyclerViewEnum.LOADING
        set(value) {
            field = value
    var emptyStateView: View? = null
    var loadingStateView: View? = null

    constructor(context: Context) : super(context) {}

    constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {}

    constructor(context: Context, attrs: AttributeSet, defStyle: Int) : super(context, attrs, defStyle) {}

    private val dataObserver = object : AdapterDataObserver() {
        override fun onChanged() {

        override fun onItemRangeRemoved(positionStart: Int, itemCount: Int) {
            super.onItemRangeRemoved(positionStart, itemCount)

        override fun onItemRangeInserted(positionStart: Int, itemCount: Int) {
            super.onItemRangeInserted(positionStart, itemCount)

    override fun setAdapter(adapter: RecyclerView.Adapter<*>?) {

    fun onChangeState() {
        if (adapter?.itemCount == 0) {
            emptyStateView?.visibility = View.VISIBLE
            loadingStateView?.visibility = View.GONE
            [email protected] = View.GONE
        } else {
            emptyStateView?.visibility = View.GONE
            loadingStateView?.visibility = View.GONE
            [email protected] = View.VISIBLE

    private fun setState() {

        when (this.stateView) {
            RecyclerViewEnum.LOADING -> {
                loadingStateView?.visibility = View.VISIBLE
                [email protected] = View.GONE
                emptyStateView?.visibility = View.GONE

            RecyclerViewEnum.NORMAL -> {
                loadingStateView?.visibility = View.GONE
                [email protected] = View.VISIBLE
                emptyStateView?.visibility = View.GONE
            RecyclerViewEnum.EMPTY_STATE -> {
                loadingStateView?.visibility = View.GONE
                [email protected] = View.GONE
                emptyStateView?.visibility = View.VISIBLE


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android=""


            android:text="empty" />


            android:theme="@style/progressBarBlue" />

        android:layout_height="match_parent" />

in activity use this way:

recyclerView?.apply {
        layoutManager = GridLayoutManager(context, 2)
        emptyStateView = emptyView
        loadingStateView = loadingView
        adapter = adapterGrid

    // you can set LoadingView or emptyView manual
    recyclerView.stateView = RecyclerViewEnum.EMPTY_STATE
    recyclerView.stateView = RecyclerViewEnum.LOADING

How can JavaScript save to a local file?

Based on

var fileContent = "My epic novel that I don't want to lose.";
var bb = new Blob([fileContent ], { type: 'text/plain' });
var a = document.createElement('a'); = 'download.txt';
a.href = window.URL.createObjectURL(bb);;

Modified the original fiddle:

Auto-refreshing div with jQuery - setTimeout or another method?

Another modification:

function update() {
  $.get("response.php", function(data) {
    window.setTimeout(update, 10000);

The difference with this is that it waits 10 seconds AFTER the ajax call is one. So really the time between refreshes is 10 seconds + length of ajax call. The benefit of this is if your server takes longer than 10 seconds to respond, you don't get two (and eventually, many) simultaneous AJAX calls happening.

Also, if the server fails to respond, it won't keep trying.

I've used a similar method in the past using .ajax to handle even more complex behaviour:

function update() {
    type: 'GET',
    url: 'response.php',
    timeout: 2000,
    success: function(data) {
      window.setTimeout(update, 10000);
    error: function (XMLHttpRequest, textStatus, errorThrown) {
      $("#notice_div").html('Timeout contacting server..');
      window.setTimeout(update, 60000);

This shows a loading message while loading (put an animated gif in there for typical "web 2.0" style). If the server times out (in this case takes longer than 2s) or any other kind of error happens, it shows an error, and it waits for 60 seconds before contacting the server again.

This can be especially beneficial when doing fast updates with a larger number of users, where you don't want everyone to suddenly cripple a lagging server with requests that are all just timing out anyways.

A valid provisioning profile for this executable was not found... (again)

If none of above stated works then check for your device date, make sure your device date doesn't exceed profile expiry date i.e. not set to far future.

Toolbar overlapping below status bar

None of the answers worked for me, but this is what finally worked after i set android:fitSystemWindows on the root view(I set these in styles v21):

<item name="android:windowDrawsSystemBarBackgrounds">true</item>
<item name="android:windowTranslucentStatus">false</item>

Make sure you don't have the following line as AS puts it by default:

<item name="android:statusBarColor">@android:color/transparent</item>

Use of 'const' for function parameters

When I coded C++ for a living I consted everything I possibly could. Using const is a great way to help the compiler help you. For instance, const-ing your method return values can save you from typos such as:

foo() = 42

when you meant:

foo() == 42

If foo() is defined to return a non-const reference:

int& foo() { /* ... */ }

The compiler will happily let you assign a value to the anonymous temporary returned by the function call. Making it const:

const int& foo() { /* ... */ }

Eliminates this possibility.

Find the files that have been changed in last 24 hours

For others who land here in the future (including myself), add a -name option to find specific file types, for instance: find /var -name "*.php" -mtime -1 -ls

Replace a character at a specific index in a string?

this will work

   String myName="domanokz";
   String p=myName.replace(myName.charAt(4),'x');

Output : domaxokz

How to create timer in angular2

I faced a problem that I had to use a timer, but I had to display them in 2 component same time, same screen. I created the timerObservable in a service. I subscribed to the timer in both component, and what happened? It won't be synched, cause new subscription always creates its own stream.

What I would like to say, is that if you plan to use one timer at several places, always put .publishReplay(1).refCount() at the end of the Observer, cause it will publish the same stream out of it every time.


this.startDateTimer = Observable.combineLatest(this.timer, this.startDate$, (localTimer, startDate) => {
  return this.calculateTime(startDate);

Pylint, PyChecker or PyFlakes?

Well, I am a bit curious, so I just tested the three myself right after asking the question ;-)

Ok, this is not a very serious review, but here is what I can say:

I tried the tools with the default settings (it's important because you can pretty much choose your check rules) on the following script:

# by Daniel Rosengren modified by e-satis

import sys, time
stdout = sys.stdout


class Iterator(object) :

    def __init__(self):

        print 'Rendering...'
        for y in xrange(-39, 39):
            for x in xrange(-39, 39):
                if self.mandelbrot(x/40.0, y/40.0) :
                    stdout.write(' ')

    def mandelbrot(self, x, y):
        cr = y - 0.5
        ci = x
        zi = 0.0
        zr = 0.0

        for i in xrange(MAX_ITERATIONS) :
            temp = zr * zi
            zr2 = zr * zr
            zi2 = zi * zi
            zr = zr2 - zi2 + cr
            zi = temp + temp + ci

            if zi2 + zr2 > BAILOUT:
                return i

        return 0

t = time.time()
print '\nPython Elapsed %.02f' % (time.time() - t)

As a result:

  • PyChecker is troublesome because it compiles the module to analyze it. If you don't want your code to run (e.g, it performs a SQL query), that's bad.
  • PyFlakes is supposed to be light. Indeed, it decided that the code was perfect. I am looking for something quite severe so I don't think I'll go for it.
  • PyLint has been very talkative and rated the code 3/10 (OMG, I'm a dirty coder !).

Strong points of PyLint:

  • Very descriptive and accurate report.
  • Detect some code smells. Here it told me to drop my class to write something with functions because the OO approach was useless in this specific case. Something I knew, but never expected a computer to tell me :-p
  • The fully corrected code run faster (no class, no reference binding...).
  • Made by a French team. OK, it's not a plus for everybody, but I like it ;-)

Cons of Pylint:

  • Some rules are really strict. I know that you can change it and that the default is to match PEP8, but is it such a crime to write 'for x in seq'? Apparently yes because you can't write a variable name with less than 3 letters. I will change that.
  • Very very talkative. Be ready to use your eyes.

Corrected script (with lazy doc strings and variable names):

# by Daniel Rosengren, modified by e-satis
Module doctring

import time
from sys import stdout


def mandelbrot(dim_1, dim_2):
    function doc string
    cr1 = dim_1 - 0.5
    ci1 = dim_2
    zi1 = 0.0
    zr1 = 0.0

    for i in xrange(MAX_ITERATIONS) :
        temp = zr1 * zi1
        zr2 = zr1 * zr1
        zi2 = zi1 * zi1
        zr1 = zr2 - zi2 + cr1
        zi1 = temp + temp + ci1

        if zi2 + zr2 > BAILOUT:
            return i

    return 0

def execute() :
    func doc string
    print 'Rendering...'
    for dim_1 in xrange(-39, 39):
        for dim_2 in xrange(-39, 39):
            if mandelbrot(dim_1/40.0, dim_2/40.0) :
                stdout.write(' ')

START_TIME = time.time()
print '\nPython Elapsed %.02f' % (time.time() - START_TIME)

Thanks to Rudiger Wolf, I discovered pep8 that does exactly what its name suggests: matching PEP8. It has found several syntax no-nos that Pylint did not. But Pylint found stuff that was not specifically linked to PEP8 but interesting. Both tools are interesting and complementary.

Eventually I will use both since there are really easy to install (via packages or setuptools) and the output text is so easy to chain.

To give you a little idea of their output:


./ E401 multiple imports on one line
./ E302 expected 2 blank lines, found 1
./ E203 whitespace before ':'
./ E501 line too long (108 characters)
./ W291 trailing whitespace
./ E301 expected 1 blank line, found 3


************* Module python_mandelbrot
C: 15: Line too long (108/80)
C: 61: Line too long (85/80)
C:  1: Missing docstring
C:  5: Invalid name "stdout" (should match (([A-Z_][A-Z0-9_]*)|(__.*__))$)
C: 10:Iterator: Missing docstring
C: 15:Iterator.__init__: Invalid name "y" (should match [a-z_][a-z0-9_]{2,30}$)
C: 17:Iterator.__init__: Invalid name "x" (should match [a-z_][a-z0-9_]{2,30}$)

[...] and a very long report with useful stats like :


|                         |now   |previous |difference |
|nb duplicated lines      |0     |0        |=          |
|percent duplicated lines |0.000 |0.000    |=          |

What does MissingManifestResourceException mean and how to fix it?

Also the same error may occur when you put a new class into the source code of a designer created form's class.

This new class may be removed, and placed in a different cs file.

(At least in my case this was the problem...)

Crystal Reports - Adding a parameter to a 'Command' query

Try this:

Select Project_Name, ReleaseDate, TaskName
From DB_Table
Where Project_Name like '{?Pm-?Proj_Name}'
  And ReleaseDate >= currentdate

currentdate should be a valid database function or field to work. If you are using MS SQL Server, use GETDATE() instead.

If all you want is to filter records in a subreport based on a parameter from the main report, it might be easier to simply add the table to the subreport, and then create a Project_Name link between the main report and subreport. You can then use the Select Expert to filter the ReleaseDate as well.

Prevent screen rotation on Android

You can try This way

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android=""

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <activity android:name=".Login_Activity"
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />

How do I properly set the permgen size?

Don't put the environment configuration in catalina.bat/ Instead you should create a new file in CATALINA_BASE\bin\setenv.bat to keep your customizations separate of tomcat installation.

How to loop over files in directory and change path and add suffix to filename

You can use finds null separated output option with read to iterate over directory structures safely.

find . -type f -print0 | while IFS= read -r -d $'\0' file; 
  do echo "$file" ;

So for your case

find . -maxdepth 1 -type f  -print0 | while IFS= read -r -d $'\0' file; do
  for ((i=0; i<=3; i++)); do
    ./MyProgram.exe "$file" 'Logs/'"`basename "$file"`""$i"'.txt'


while IFS= read -r -d $'\0' file; do
  for ((i=0; i<=3; i++)); do
    ./MyProgram.exe "$file" 'Logs/'"`basename "$file"`""$i"'.txt'
done < <(find . -maxdepth 1 -type f  -print0)

will run the while loop in the current scope of the script ( process ) and allow the output of find to be used in setting variables if needed

react-native: command not found

Install react-native-cli with npm install -g react-native-cli. You may need to use sudo like sudo npm install -g react-native-cli

How to compare files from two different branches?

In order to compare two files in the git bash you need to use the command:

git diff <Branch name>..master -- Filename.extension   

This command will show the difference between the two files in the bash itself.

Python 3 ImportError: No module named 'ConfigParser'

This worked for me

cp /usr/local/lib/python3.5/ /usr/local/lib/python3.5/

In Java, how do I convert a byte array to a string of hex digits while keeping leading zeros?

static String toHex(byte[] digest) {
    String digits = "0123456789abcdef";
    StringBuilder sb = new StringBuilder(digest.length * 2);
    for (byte b : digest) {
        int bi = b & 0xff;
        sb.append(digits.charAt(bi >> 4));
        sb.append(digits.charAt(bi & 0xf));
    return sb.toString();

Add onClick event to document.createElement("th")

var newTH = document.createElement('th');
newTH.setAttribute("onclick", "removeColumn(#)");
newTH.setAttribute("id", "#");

function removeColumn(#){
// remove column #

How to Load an Assembly to AppDomain with all references recursively?

You need to invoke CreateInstanceAndUnwrap before your proxy object will execute in the foreign application domain.

 class Program
    static void Main(string[] args)
        AppDomainSetup domaininfo = new AppDomainSetup();
        domaininfo.ApplicationBase = System.Environment.CurrentDirectory;
        Evidence adevidence = AppDomain.CurrentDomain.Evidence;
        AppDomain domain = AppDomain.CreateDomain("MyDomain", adevidence, domaininfo);

        Type type = typeof(Proxy);
        var value = (Proxy)domain.CreateInstanceAndUnwrap(

        var assembly = value.GetAssembly(args[0]);
        // AppDomain.Unload(domain);

public class Proxy : MarshalByRefObject
    public Assembly GetAssembly(string assemblyPath)
            return Assembly.LoadFile(assemblyPath);
        catch (Exception)
            return null;
            // throw new InvalidOperationException(ex);

Also, note that if you use LoadFrom you'll likely get a FileNotFound exception because the Assembly resolver will attempt to find the assembly you're loading in the GAC or the current application's bin folder. Use LoadFile to load an arbitrary assembly file instead--but note that if you do this you'll need to load any dependencies yourself.

Base64 String throwing invalid character error

You say

The string is exactly what was written to the file (with the addition of a "\0" at the end, but I don't think that even does anything).

In fact, it does do something (it causes your code to throw a FormatException:"Invalid character in a Base-64 string") because the Convert.FromBase64String does not consider "\0" to be a valid Base64 character.

  byte[] data1 = Convert.FromBase64String("AAAA\0"); // Throws exception
  byte[] data2 = Convert.FromBase64String("AAAA");   // Works

Solution: Get rid of the zero termination. (Maybe call .Trim("\0"))


The MSDN docs for Convert.FromBase64String say it will throw a FormatException when

The length of s, ignoring white space characters, is not zero or a multiple of 4.


The format of s is invalid. s contains a non-base 64 character, more than two padding characters, or a non-white space character among the padding characters.

and that

The base 64 digits in ascending order from zero are the uppercase characters 'A' to 'Z', lowercase characters 'a' to 'z', numerals '0' to '9', and the symbols '+' and '/'.

Switch to selected tab by name in Jquery-UI Tabs

I had trouble getting any of the answers to work as they were based on the older versions of JQuery UI. We're using 1.11.4 (CDN Reference).

Here is my Fiddle with working code: I ended up splicing together bits from four or five different threads to get mine to work:


    //selects the tab index of the <li> relative to the div it is contained within
    $(".btn_tab3").click(function () {
        $( "#tabs" ).tabs( "option", "active", 2 );

    //selects the tab by id of the <li>
    $(".btn_tab3_id").click(function () {
      function selectTab(tabName) {
          $("#tabs").tabs("option", "active", $(tabName + "").index());


How can one use multi threading in PHP applications

pcntl_fork won't work in a web server environment if it has safe mode turned on. In this case, it will only work in the CLI version of PHP.

How does MySQL CASE work?

I wanted a simple example of the use of case that I could play with, this doesn't even need a table. This returns odd or even depending whether seconds is odd or even


Drop rows containing empty cells from a pandas DataFrame

Pythonic + Pandorable: df[df['col'].astype(bool)]

Empty strings are falsy, which means you can filter on bool values like this:

df = pd.DataFrame({
    'A': range(5),
    'B': ['foo', '', 'bar', '', 'xyz']
   A    B
0  0  foo
1  1     
2  2  bar
3  3     
4  4  xyz
0     True
1    False
2     True
3    False
4     True
Name: B, dtype: bool

   A    B
0  0  foo
2  2  bar
4  4  xyz

If your goal is to remove not only empty strings, but also strings only containing whitespace, use str.strip beforehand:

   A    B
0  0  foo
2  2  bar
4  4  xyz

Faster than you Think

.astype is a vectorised operation, this is faster than every option presented thus far. At least, from my tests. YMMV.

Here is a timing comparison, I've thrown in some other methods I could think of.

enter image description here

Benchmarking code, for reference:

import pandas as pd
import perfplot

df1 = pd.DataFrame({
    'A': range(5),
    'B': ['foo', '', 'bar', '', 'xyz']
    setup=lambda n: pd.concat([df1] * n, ignore_index=True),
        lambda df: df[df['B'].astype(bool)],
        lambda df: df[df['B'] != ''],
        lambda df: df[df['B'].replace('', np.nan).notna()],  # optimized 1-col
        lambda df: df.replace({'B': {'': np.nan}}).dropna(subset=['B']),  
    labels=['astype', "!= ''", "replace + notna", "replace + dropna", ],
    n_range=[2**k for k in range(1, 15)],

What is the best way to convert an array to a hash in Ruby


Ruby 2.1.0 is released today. And I comes with Array#to_h (release notes and ruby-doc), which solves the issue of converting an Array to a Hash.

Ruby docs example:

[[:foo, :bar], [1, 2]].to_h    # => {:foo => :bar, 1 => 2}

Python - AttributeError: 'numpy.ndarray' object has no attribute 'append'

Numpy arrays do not have an append method. Use the Numpy append function instead:

import numpy as np

array_3 = np.append(array_1, array_2, axis=n)
# you can either specify an integer axis value n or remove the keyword argument completely

For example, if array_1 and array_2 have the following values:

array_1 = np.array([1, 2])
array_2 = np.array([3, 4])

If you call np.append without specifying an axis value, like so:

array_3 = np.append(array_1, array_2)

array_3 will have the following value:

array([1, 2, 3, 4])

Else, if you call np.append with an axis value of 0, like so:

array_3 = np.append(array_1, array_2, axis=0)

array_3 will have the following value:

 array([[1, 2],
        [3, 4]]) 

More information on the append function here:

How to asynchronously call a method in Java

Java also provides a nice way of calling async methods. in java.util.concurrent we have ExecutorService that helps in doing the same. Initialize your object like this -

 private ExecutorService asyncExecutor = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());

and then call the function like-

asyncExecutor.execute(() -> {


How can I check if some text exist or not in the page using Selenium?


if content.find("text_to_search"): 
    print("text is present in the webpage")

Download the html page and use find()

Get Selected value from dropdown using JavaScript

Maybe it's the comma in your if condition.

function answers() {
var answer=document.getElementById("mySelect");
 if(answer[answer.selectedIndex].value == "To measure time.") {
  alert("That's correct!"); 

You can also write it like this.

function answers(){
 document.getElementById("mySelect").value!="To measure time."||(alert('That's correct!'))

How do I protect javascript files?

Google Closure Compiler, YUI compressor, Minify, /Packer/... etc, are options for compressing/obfuscating your JS codes. But none of them can help you from hiding your code from the users.

Anyone with decent knowledge can easily decode/de-obfuscate your code using tools like JS Beautifier. You name it.

So the answer is, you can always make your code harder to read/decode, but for sure there is no way to hide.

Facebook API "This app is in development mode"

App Review > Make {Your App} public? > Yes

Click app review and Turn on the Make your app Public toggle. Save changes

Python script to do something at the same time every day

APScheduler might be what you are after.

from datetime import date
from apscheduler.scheduler import Scheduler

# Start the scheduler
sched = Scheduler()

# Define the function that is to be executed
def my_job(text):
    print text

# The job will be executed on November 6th, 2009
exec_date = date(2009, 11, 6)

# Store the job in a variable in case we want to cancel it
job = sched.add_date_job(my_job, exec_date, ['text'])

# The job will be executed on November 6th, 2009 at 16:30:05
job = sched.add_date_job(my_job, datetime(2009, 11, 6, 16, 30, 5), ['text'])

You can just get it to schedule another run by building that into the function you are scheduling.

There is no tracking information for the current branch

I was trying the above examples and couldn't get them to sync with a (non-master) branch I had created on a different computer. For background, I created this repository on computer A (git v 1.8) and then cloned the repository onto computer B (git 2.14). I made all my changes on comp B, but when I tried to pull the changes onto computer A I was unable to do so, getting the same above error. Similar to the above solutions, I had to do:

git branch --set-upstream-to=origin/<my_repository_name> 
git pull

slightly different but hopefully helps someone

How do I read CSV data into a record array in NumPy?

In [329]: %time my_data = genfromtxt('one.csv', delimiter=',')
CPU times: user 19.8 s, sys: 4.58 s, total: 24.4 s
Wall time: 24.4 s

In [330]: %time df = pd.read_csv("one.csv", skiprows=20)
CPU times: user 1.06 s, sys: 312 ms, total: 1.38 s
Wall time: 1.38 s

When can I use a forward declaration?

None of the answers so far describe when one can use a forward declaration of a class template. So, here it goes.

A class template can be forwarded declared as:

template <typename> struct X;

Following the structure of the accepted answer,

Here's what you can and cannot do.

What you can do with an incomplete type:

  • Declare a member to be a pointer or a reference to the incomplete type in another class template:

    template <typename T>
    class Foo {
        X<T>* ptr;
        X<T>& ref;
  • Declare a member to be a pointer or a reference to one of its incomplete instantiations:

    class Foo {
        X<int>* ptr;
        X<int>& ref;
  • Declare function templates or member function templates which accept/return incomplete types:

    template <typename T>
       void      f1(X<T>);
    template <typename T>
       X<T>    f2();
  • Declare functions or member functions which accept/return one of its incomplete instantiations:

    void      f1(X<int>);
    X<int>    f2();
  • Define function templates or member function templates which accept/return pointers/references to the incomplete type (but without using its members):

    template <typename T>
       void      f3(X<T>*, X<T>&) {}
    template <typename T>
       X<T>&   f4(X<T>& in) { return in; }
    template <typename T>
       X<T>*   f5(X<T>* in) { return in; }
  • Define functions or methods which accept/return pointers/references to one of its incomplete instantiations (but without using its members):

    void      f3(X<int>*, X<int>&) {}
    X<int>&   f4(X<int>& in) { return in; }
    X<int>*   f5(X<int>* in) { return in; }
  • Use it as a base class of another template class

    template <typename T>
    class Foo : X<T> {} // OK as long as X is defined before
                        // Foo is instantiated.
    Foo<int> a1; // Compiler error.
    template <typename T> struct X {};
    Foo<int> a2; // OK since X is now defined.
  • Use it to declare a member of another class template:

    template <typename T>
    class Foo {
        X<T> m; // OK as long as X is defined before
                // Foo is instantiated. 
    Foo<int> a1; // Compiler error.
    template <typename T> struct X {};
    Foo<int> a2; // OK since X is now defined.
  • Define function templates or methods using this type

    template <typename T>
      void    f1(X<T> x) {}    // OK if X is defined before calling f1
    template <typename T>
      X<T>    f2(){return X<T>(); }  // OK if X is defined before calling f2
    void test1()
       f1(X<int>());  // Compiler error
       f2<int>();     // Compiler error
    template <typename T> struct X {};
    void test2()
       f1(X<int>());  // OK since X is defined now
       f2<int>();     // OK since X is defined now

What you cannot do with an incomplete type:

  • Use one of its instantiations as a base class

    class Foo : X<int> {} // compiler error!
  • Use one of its instantiations to declare a member:

    class Foo {
        X<int> m; // compiler error!
  • Define functions or methods using one of its instantiations

    void      f1(X<int> x) {}            // compiler error!
    X<int>    f2() {return X<int>(); }   // compiler error!
  • Use the methods or fields of one of its instantiations, in fact trying to dereference a variable with incomplete type

    class Foo {
        X<int>* m;            
        void method()            
            m->someMethod();      // compiler error!
            int i = m->someField; // compiler error!
  • Create explicit instantiations of the class template

    template struct X<int>;

Entity Framework - Code First - Can't Store List<String>

I Know this is a old question, and Pawel has given the correct answer, I just wanted to show a code example of how to do some string processing, and avoid an extra class for the list of a primitive type.

public class Test
    public Test()
        _strings = new List<string>

    public int Id { get; set; }

    private List<String> _strings { get; set; }

    public List<string> Strings
        get { return _strings; }
        set { _strings = value; }

    public string StringsAsString
        get { return String.Join(',', _strings); }
        set { _strings = value.Split(',').ToList(); }

Getting year in moment.js

The year() function just retrieves the year component of the underlying Date object, so it returns a number.

Calling format('YYYY') will invoke moment's string formatting functions, which will parse the format string supplied, and build a new string containing the appropriate data. Since you only are passing YYYY, then the result will be a string containing the year.

If all you need is the year, then use the year() function. It will be faster, as there is less work to do.

Do note that while years are the same in this regard, months are not! Calling format('M') will return months in the range 1-12. Calling month() will return months in the range 0-11. This is due to the same behavior of the underlying Date object.

How to rebase local branch onto remote master

First fetch the new master from the upstream repository, then rebase your work branch on that:

git fetch origin            # Updates origin/master
git rebase origin/master    # Rebases current branch onto origin/master

Update: Please see Paul Draper's answer for a more concise way to do the same - recent Git versions provide a simpler way to do the equivalent of the above two commands.

What are WSDL, SOAP and REST?

Example: In a simple terms if you have a web service of calculator.

WSDL: WSDL tells about the functions that you can implement or exposed to the client. For example: add, delete, subtract and so on.

SOAP: Where as using SOAP you actually perform actions like doDelete(), doSubtract(), doAdd(). So SOAP and WSDL are apples and oranges. We should not compare them. They both have their own different functionality.

Why we use SOAP and WSDL: For platform independent data exchange.

EDIT: In a normal day to day life example:

WSDL: When we go to a restaurant we see the Menu Items, those are the WSDL's.

Proxy Classes: Now after seeing the Menu Items we make up our Mind (Process our mind on what to order): So, basically we make Proxy classes based on WSDL Document.

SOAP: Then when we actually order the food based on the Menu's: Meaning we use proxy classes to call upon the service methods which is done using SOAP. :)

How to override !important?

Override using JavaScript

$('.mytable td').attr('style', 'display: none !important');

Worked for me.

IF-THEN-ELSE statements in postgresql

In general, an alternative to case when ... is coalesce(nullif(x,bad_value),y) (that cannot be used in OP's case). For example,

select coalesce(nullif(y,''),x), coalesce(nullif(x,''),y), *
from (     (select 'abc' as x, '' as y)
 union all (select 'def' as x, 'ghi' as y)
 union all (select '' as x, 'jkl' as y)
 union all (select null as x, 'mno' as y)
 union all (select 'pqr' as x, null as y)
) q


 coalesce | coalesce |  x  |  y  
 abc      | abc      | abc | 
 ghi      | def      | def | ghi
 jkl      | jkl      |     | jkl
 mno      | mno      |     | mno
 pqr      | pqr      | pqr | 
(5 rows)

Python regex to match dates

Using this regular expression you can validate different kinds of Date/Time samples, just a little change is needed.

^\d\d\d\d/(0?[1-9]|1[0-2])/(0?[1-9]|[12][0-9]|3[01]) (00|[0-9]|1[0-9]|2[0-3]):([0-9]|[0-5][0-9]):([0-9]|[0-5][0-9])$ -->validate this: 2018/7/12 13:00:00

for your format you cad change it to:

^(0?[1-9]|[12][0-9]|3[01])/(0?[1-9]|1[0-2])/\d\d$ --> validates this: 11/12/98

Re-ordering columns in pandas dataframe based on column name

df = df.reindex(sorted(df.columns), axis=1)

This assumes that sorting the column names will give the order you want. If your column names won't sort lexicographically (e.g., if you want column Q10.3 to appear after Q9.1), you'll need to sort differently, but that has nothing to do with pandas.

Setting Margin Properties in code

One could simply use this

MyControl.Margin = new System.Windows.Thickness(10, 0, 5, 0);

Dealing with "Xerces hell" in Java/Maven?

My friend that's very simple, here an example:


And if you want to check in the terminal(windows console for this example) that your maven tree has no problems:

mvn dependency:tree -Dverbose | grep --color=always '(.* conflict\|^' | less -r

ValueError: Wrong number of items passed - Meaning and suggestions?

Not sure if this is relevant to your question but it might be relevant to someone else in the future: I had a similar error. Turned out that the df was empty (had zero rows) and that is what was causing the error in my command.

Check if date is in the past Javascript

function isPrevDate() {
    alert("startDate is " + Startdate);
    if(Startdate.length != 0 && Startdate !='') {
        var start_date = Startdate.split('-');
        alert("Input date: "+ start_date);
        alert("start date arrray format " + start_date);
        var a = new Date(start_date);
        //alert("The date is a" +a);
        var today = new Date();
        var day = today.getDate();
        var mon = today.getMonth()+1;
        var year = today.getFullYear();
        today = (mon+"/"+day+"/"+year);
        var today = new Date(today);
        alert("Today: "+today.getTime());
        alert("a : "+a.getTime());
        if(today.getTime() > a.getTime() )
            alert("Please select Start date in range");
            return false;
        } else {
            return true;

Is it possible to use pip to install a package from a private GitHub repository?

Here's a quick method that worked for me. Simply fork the repo and install it from your own GitHub account with

pip install git+

remove double quotes from Json return data using Jquery

What you are doing is making a JSON string in your example. Either don't use the JSON.stringify() or if you ever do have JSON data coming back and you don't want quotations, Simply use JSON.parse() to remove quotations around JSON responses! Don't use regex, there's no need to.

Split string based on a regular expression

Its very simple actually. Try this:

str1="a    b     c      d"
splitStr1 = str1.split()
print splitStr1

MySql Inner Join with WHERE clause

1. Change the INNER JOIN before the WHERE clause.
2. You have two WHEREs which is not allowed.

Try this:

SELECT table1.f_id FROM table1
  INNER JOIN table2 
     ON (table2.f_id = table1.f_id AND table2.f_type = 'InProcess') 
   WHERE table1.f_com_id = '430' AND table1.f_status = 'Submitted'

Starting ssh-agent on Windows 10 fails: "unable to start ssh-agent service, error :1058"

Yeah, as others have suggested, this error seems to mean that ssh-agent is installed but its service (on windows) hasn't been started.

You can check this by running in Windows PowerShell:

> Get-Service ssh-agent

And then check the output of status is not running.

Status   Name               DisplayName
------   ----               -----------
Stopped  ssh-agent          OpenSSH Authentication Agent

Then check that the service has been disabled by running

> Get-Service ssh-agent | Select StartType


I suggest setting the service to start manually. This means that as soon as you run ssh-agent, it'll start the service. You can do this through the Services GUI or you can run the command in admin mode:

 > Get-Service -Name ssh-agent | Set-Service -StartupType Manual

Alternatively, you can set it through the GUI if you prefer.

services.msc showing the properties of the OpenSSH Agent

PHP check whether property exists in object or class

If you want to know if a property exists in an instance of a class that you have defined, simply combine property_exists() with isset().

public function hasProperty($property)
    return property_exists($this, $property) && isset($this->$property);

Difference between -XX:+UseParallelGC and -XX:+UseParNewGC

After a lot of searching, the best explanation I've found is from Java Performance Tuning website in Question of the month: 1.4.1 Garbage collection algorithms, January 29th, 2003

Young generation garbage collection algorithms

The (original) copying collector (Enabled by default). When this collector kicks in, all application threads are stopped, and the copying collection proceeds using one thread (which means only one CPU even if on a multi-CPU machine). This is known as a stop-the-world collection, because basically the JVM pauses everything else until the collection is completed.

The parallel copying collector (Enabled using -XX:+UseParNewGC). Like the original copying collector, this is a stop-the-world collector. However this collector parallelizes the copying collection over multiple threads, which is more efficient than the original single-thread copying collector for multi-CPU machines (though not for single-CPU machines). This algorithm potentially speeds up young generation collection by a factor equal to the number of CPUs available, when compared to the original singly-threaded copying collector.

The parallel scavenge collector (Enabled using -XX:UseParallelGC). This is like the previous parallel copying collector, but the algorithm is tuned for gigabyte heaps (over 10GB) on multi-CPU machines. This collection algorithm is designed to maximize throughput while minimizing pauses. It has an optional adaptive tuning policy which will automatically resize heap spaces. If you use this collector, you can only use the the original mark-sweep collector in the old generation (i.e. the newer old generation concurrent collector cannot work with this young generation collector).

From this information, it seems the main difference (apart from CMS cooperation) is that UseParallelGC supports ergonomics while UseParNewGC doesn't.

How to display a range input slider vertically

Without changing the position to absolute, see below. This supports all recent browsers as well.

.vranger {_x000D_
  margin-top: 50px;_x000D_
   transform: rotate(270deg);_x000D_
  -moz-transform: rotate(270deg); /*do same for other browsers if required*/_x000D_
<input type="range" class="vranger"/>

for very old browsers, you can use -sand-transform: rotate(10deg); from CSS sandpaper

or use

prefix selector such as -ms-transform: rotate(270deg); for IE9

Put icon inside input element in a form

This works for me for more or less standard forms:

  <button type="submit" value="Submit" name="ButtonType" id="whateveristheId" class="button-class">Submit<img src="/img/selectedImage.png" alt=""></button>

Apache 13 permission denied in user's home directory

Could be SELinux. Check the appropriate log file (/var/log/messages? - been a while since I've used a RedHat derivative) to see if that's blocking the access.

How to add multiple classes to a ReactJS Component?

You can create an element with multiple class names like this, I tryed these both way, its working fine...

If you importing any css then you can follow this way : Way 1:

import React, { Component, PropTypes } from 'react';
import csjs from 'csjs';
import styles from './styles';
import insertCss from 'insert-css';
import classNames from 'classnames';
export default class Foo extends Component {
  render() {
    return (
      <div className={[styles.class1, styles.class2].join(' ')}>
        { 'text' }

way 2:

import React, { Component, PropTypes } from 'react';
import csjs from 'csjs';
import styles from './styles';
import insertCss from 'insert-css';
import classNames from 'classnames';
export default class Foo extends Component {
  render() {
    return (
      <div className={styles.class1 + ' ' + styles.class2}>
        { 'text' }


If you applying css as internal :

const myStyle = {_x000D_
  color: "#fff"_x000D_
// React Element using Jsx_x000D_
const myReactElement = (_x000D_
  <h1 style={myStyle} className="myClassName myClassName1">_x000D_
    Hello World!_x000D_
ReactDOM.render(myReactElement, document.getElementById("app"));
.myClassName {_x000D_
  background-color: #333;_x000D_
  padding: 10px;_x000D_
  border: 2px solid #000;_x000D_
<script src=""></script>_x000D_
<script src=""></script>_x000D_
<div id="app">_x000D_

Fill remaining vertical space with CSS using display:flex

Use the flex-grow property to the main content div and give the dispaly: flex; to its parent;

body {_x000D_
    height: 100%;_x000D_
    position: absolute;_x000D_
    margin: 0;_x000D_
section {_x000D_
  height: 100%;_x000D_
  display: flex;_x000D_
  flex-direction : column;_x000D_
header {_x000D_
  background: tomato;_x000D_
div {_x000D_
  flex: 1; /* or flex-grow: 1  */;_x000D_
  overflow-x: auto;_x000D_
  background: gold;_x000D_
footer {_x000D_
  background: lightgreen;_x000D_
  min-height: 60px;_x000D_
    header: sized to content_x000D_
    <br>(but is it really?)_x000D_
    main content: fills remaining space<br>_x000D_
    footer: fixed height in px_x000D_

What exactly is a Maven Snapshot and why do we need it?

The "SNAPSHOT" term means that the build is a snapshot of your code at a given time.

It usually means that this version is still under heavy development.

When the code is ready and it is time to release it, you will want to change the version listed in the POM. Then instead of having a "SNAPSHOT" you would use a label like "1.0".

For some help with versioning, check out the Semantic Versioning specification.

How to access my localhost from another PC in LAN?

after your pc connects to other pc use these 4 step:
4 steps:
1- Edit this file: httpd.conf
for that click on wamp server and select Apache and select httpd.conf
2- Find this text: Deny from all
in the below tag:

  <Directory "c:/wamp/www"><!-- maybe other url-->

    # Possible values for the Options directive are "None", "All",
    # or any combination of:
    #   Indexes Includes FollowSymLinks SymLinksifOwnerMatch ExecCGI MultiViews
    # Note that "MultiViews" must be named *explicitly* --- "Options All"
    # doesn't give it to you.
    # The Options directive is both complicated and important.  Please see
    # for more information.
    Options Indexes FollowSymLinks

    # AllowOverride controls what directives may be placed in .htaccess files.
    # It can be "All", "None", or any combination of the keywords:
    #   AllowOverride FileInfo AuthConfig Limit
    AllowOverride All

    # Controls who can get stuff from this server.
#    Require all granted
#   onlineoffline tag - don't remove
     Order Deny,Allow
    Deny from all
     Allow from
     Allow from ::1
     Allow from localhost

3- Change to: Deny from none
like this:

<Directory "c:/wamp/www">

    # Possible values for the Options directive are "None", "All",
    # or any combination of:
    #   Indexes Includes FollowSymLinks SymLinksifOwnerMatch ExecCGI MultiViews
    # Note that "MultiViews" must be named *explicitly* --- "Options All"
    # doesn't give it to you.
    # The Options directive is both complicated and important.  Please see
    # for more information.
    Options Indexes FollowSymLinks

    # AllowOverride controls what directives may be placed in .htaccess files.
    # It can be "All", "None", or any combination of the keywords:
    #   AllowOverride FileInfo AuthConfig Limit
    AllowOverride All

    # Controls who can get stuff from this server.
#    Require all granted
#   onlineoffline tag - don't remove
     Order Deny,Allow
    Deny from none
     Allow from
     Allow from ::1
     Allow from localhost

4- Restart Apache
Don't forget restart Apache or all servises!!!

How to import existing Git repository into another?

If you want to retain the exact commit history of the second repository and therefore also retain the ability to easily merge upstream changes in the future then here is the method you want. It results in unmodified history of the subtree being imported into your repo plus one merge commit to move the merged repository to the subdirectory.

git remote add XXX_remote <path-or-url-to-XXX-repo>
git fetch XXX_remote
git merge -s ours --no-commit --allow-unrelated-histories XXX_remote/master
git read-tree --prefix=ZZZ/ -u XXX_remote/master
git commit -m "Imported XXX as a subtree."

You can track upstream changes like so:

git pull -s subtree XXX_remote master

Git figures out on its own where the roots are before doing the merge, so you don't need to specify the prefix on subsequent merges.

The downside is that in the merged history the files are unprefixed (not in a subdirectory). As a result git log ZZZ/a will show you all the changes (if any) except those in the merged history. You can do:

git log --follow -- a

but that won't show the changes other then in the merged history.

In other words, if you don't change ZZZ's files in repository XXX, then you need to specify --follow and an unprefixed path. If you change them in both repositories, then you have 2 commands, none of which shows all the changes.

Git versions before 2.9: You don’t need to pass the --allow-unrelated-histories option to git merge.

The method in the other answer that uses read-tree and skips the merge -s ours step is effectively no different than copying the files with cp and committing the result.

Original source was from github's "Subtree Merge" help article. And another useful link.

What are DDL and DML?

In layman terms suppose you want to build a house, what do you do.

DDL i.e Data Definition Language

  1. Build from scratch
  2. Rennovate it
  3. Destroy the older one and recreate it from scratch

that is

  2. ALTER

DML i.e. Data Manipulation Language

People come/go inside/from your house


DCL i.e. Data Control Language

You want to control the people what part of the house they are allowed to access and kind of access.


Requery a subform from another form?

Just discovered that if the source table for a subform is updated using adodb, it takes a while until the requery can find the updated information.

In my case, I was adding some records with 'dbconn.execute "sql" ' and wondered why the requery command in vba doesn't seem to work. When I was debugging, the requery worked. Added a 2-3 second wait in the code before requery just to test made a difference.

But changing to 'currentdb.execute "sql" ' fixed the problem immediately.

How to redirect in a servlet filter?

Try and check of your ServletResponse response is an instanceof HttpServletResponse like so:

if (response instanceof HttpServletResponse) {

<input type="file"> limit selectable files by extensions

 function uploadFile() {
     var fileElement = document.getElementById("fileToUpload");
        var fileExtension = "";
        if (fileElement.value.lastIndexOf(".") > 0) {
            fileExtension = fileElement.value.substring(fileElement.value.lastIndexOf(".") + 1, fileElement.value.length);
        if (fileExtension == "odx-d"||fileExtension == "odx"||fileExtension == "pdx"||fileExtension == "cmo"||fileExtension == "xml") {
         var fd = new FormData();
        fd.append("fileToUpload", document.getElementById('fileToUpload').files[0]);
        var xhr = new XMLHttpRequest();
        xhr.upload.addEventListener("progress", uploadProgress, false);
        xhr.addEventListener("load", uploadComplete, false);
        xhr.addEventListener("error", uploadFailed, false);
        xhr.addEventListener("abort", uploadCanceled, false);"POST", "/post_uploadReq");
        else {
            alert("You must select a valid odx,pdx,xml or cmo file for upload");
            return false;

tried this , works very well

Split files using tar, gz, zip, or bzip2

Tested code, initially creates a single archive file, then splits it:

 gzip -c file.orig > file.gz
 PARTCNT=$[$(stat -c%s file.gz) / $CHUNKSIZE]

 # the remainder is taken care of, for example for
 # 1 GiB + 1 bytes PARTCNT is 1 and seq 0 $PARTCNT covers
 # all of file
 for n in `seq 0 $PARTCNT`
       dd if=file.gz of=part.$n bs=$CHUNKSIZE skip=$n count=1

This variant omits creating a single archive file and goes straight to creating parts:

gzip -c file.orig |
    ( CHUNKSIZE=1073741824;
        while true; do
            head -c "$CHUNKSIZE" > "part.$i";
            [ "$CHUNKSIZE" -eq $(stat -c%s "part.$i") ] || break;
        done; )

In this variant, if the archive's file size is divisible by $CHUNKSIZE, then the last partial file will have file size 0 bytes.

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

You can use built-in map function:

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

or list comprehensions that is a bit more pythonic:

result = [x * P for x in S]

XAMPP PORT 80 is Busy / EasyPHP error in Apache configuration file:

SQL Server Reporting Services (SSRS)
SSRS can remain active even if you uninstall SQL Server.
To stop the service:

Open SQL Server Configuration Manager. Select “SQL Server Services” in the left-hand pane. Double-click “SQL Server Reporting Services”. Hit Stop. Switch to the Service tab and set the Start Mode to “Manual”.

Irritatingly, Skype can switch to port 80. To disable it, select
Tools > Options > Advanced > Connection then uncheck
“Use port 80 and 443 as alternatives for incoming connections”.

IIS (Microsoft Internet Information Server)

For Windows 7 (or vista) its the most likely culprit. You can stop the service from the command line.

Open command line cmd.exe and type:

net stop was /y

For older versions of Windows type:

net stop iisadmin /y


If this does not solve the problem further detective work is necessary if IIS, SSRS and Skype are not to blame. Enter the following on the command line:

netstat -ao

The active TCP addresses and ports will be listed. Locate the line with local address “" and note the PID value. Start Task Manager. Navigate to the Processes tab and, if necessary, click View > Select Columns to ensure “PID (Process Identifier)” is checked. You can now locate the PID you noted above. The description and properties should help you determine which application is using the port.

Difference between Pig and Hive? Why have both?

  1. Pig-latin is data flow style, is more suitable for software engineer. While sql is more suitable for analytics person who are get used to sql. For complex task, for hive you have to manually to create temporary table to store intermediate data, but it is not necessary for pig.

  2. Pig-latin is suitable for complicated data structure( like small graph). There's a data structure in pig called DataBag which is a collection of Tuple. Sometimes you need to calculate metrics which involve multiple tuples ( there's a hidden link between tuples, in this case I would call it graph). In this case, it is very easy to write a UDF to calculate the metrics which involve multiple tuples. Of course it could be done in hive, but it is not so convenient as it is in pig.

  3. Writing UDF in pig much is easier than in Hive in my opinion.

  4. Pig has no metadata support, (or it is optional, in future it may integrate hcatalog). Hive has tables' metadata stored in database.

  5. You can debug pig script in local environment, but it would be hard for hive to do that. The reason is point 3. You need to set up hive metadata in your local environment, very time consuming.

How to use doxygen to create UML class diagrams from C++ source

Quote from this post (it's written by the author of doxygen himself) :

run doxygen -g and change the following options of the generated Doxyfile:

    EXTRACT_ALL            = YES
    HAVE_DOT               = YES
    UML_LOOK               = YES

run doxygen again

Angular 5 Button Submit On Enter Key Press

In addition to other answers which helped me, you can also add to surrounding div. In my case this was for sign on with user Name/Password fields.

<div (keyup.enter)="login()" class="container-fluid">

PHP - include a php file and also send query parameters

If you are going to write this include manually in the PHP file - the answer of Daff is perfect.

Anyway, if you need to do what was the initial question, here is a small simple function to achieve that:

// Include php file from string with GET parameters
function include_get($phpinclude)
    // find ? if available
    $pos_incl = strpos($phpinclude, '?');
    if ($pos_incl !== FALSE)
        // divide the string in two part, before ? and after
        // after ? - the query string
        $qry_string = substr($phpinclude, $pos_incl+1);
        // before ? - the real name of the file to be included
        $phpinclude = substr($phpinclude, 0, $pos_incl);
        // transform to array with & as divisor
        $arr_qstr = explode('&',$qry_string);
        // in $arr_qstr you should have a result like this:
        //   ('id=123', 'active=no', ...)
        foreach ($arr_qstr as $param_value) {
            // for each element in above array, split to variable name and its value
            list($qstr_name, $qstr_value) = explode('=', $param_value);
            // $qstr_name will hold the name of the variable we need - 'id', 'active', ...
            // $qstr_value - the corresponding value
            // $$qstr_name - this construction creates variable variable
            // this means from variable $qstr_name = 'id', adding another $ sign in front you will receive variable $id
            // the second iteration will give you variable $active and so on
            $$qstr_name = $qstr_value;
    // now it's time to include the real php file
    // all necessary variables are already defined and will be in the same scope of included file


I'm using this variable variable construction very often.

Unable to load script from assets on windows

In my case, I have removed below line from (Which is previously mistakenly added by me.):-

import com.facebook.react.BuildConfig;

After that Clean Project and hit command

react-native run-android

#if DEBUG vs. Conditional("DEBUG")

Well, it's worth noting that they don't mean the same thing at all.

If the DEBUG symbol isn't defined, then in the first case the SetPrivateValue itself won't be called... whereas in the second case it will exist, but any callers who are compiled without the DEBUG symbol will have those calls omitted.

If the code and all its callers are in the same assembly this difference is less important - but it means that in the first case you also need to have #if DEBUG around the calling code as well.

Personally I'd recommend the second approach - but you do need to keep the difference between them clear in your head.

Adding class to element using Angular JS

Try this..

If jQuery is available, angular.element is an alias for the jQuery function.

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

app.controller('Ctrl', function($scope) {


<div id='div1'>Text</div>
<button ng-click="click()">action</button>


Hide text using css

The answer is to create a span with the property


You can find an example at this site

Purpose of a constructor in Java?

A Java constructor has the same name as the name of the class to which it belongs.

Constructor’s syntax does not include a return type, since constructors never return a value.

Constructor is always called when object is created. example:- Default constructor

class Student3{  
    int id;  
    String name;  
    void display(){System.out.println(id+" "+name);}  
    public static void main(String args[]){  
        Student3 s1=new Student3();  
        Student3 s2=new Student3();  


0 null
0 null

Explanation: In the above class,you are not creating any constructor so compiler provides you a default constructor.Here 0 and null values are provided by default constructor.

Example of parameterized constructor

In this example, we have created the constructor of Student class that have two parameters. We can have any number of parameters in the constructor.

class Student4{  
    int id;  
    String name;  
    Student4(int i,String n){  
        id = i;  
        name = n;  
    void display(){System.out.println(id+" "+name);}  
    public static void main(String args[]){  
        Student4 s1 = new Student4(111,"Karan");  
        Student4 s2 = new Student4(222,"Aryan");  


111 Karan
222 Aryan

What is Mocking?

There are plenty of answers on SO and good posts on the web about mocking. One place that you might want to start looking is the post by Martin Fowler Mocks Aren't Stubs where he discusses a lot of the ideas of mocking.

In one paragraph - Mocking is one particlar technique to allow testing of a unit of code with out being reliant upon dependencies. In general, what differentiates mocking from other methods is that mock objects used to replace code dependencies will allow expectations to be set - a mock object will know how it is meant to be called by your code and how to respond.

Your original question mentioned TypeMock, so I've left my answer to that below:

TypeMock is the name of a commercial mocking framework.

It offers all the features of the free mocking frameworks like RhinoMocks and Moq, plus some more powerful options.

Whether or not you need TypeMock is highly debatable - you can do most mocking you would ever want with free mocking libraries, and many argue that the abilities offered by TypeMock will often lead you away from well encapsulated design.

As another answer stated 'TypeMocking' is not actually a defined concept, but could be taken to mean the type of mocking that TypeMock offers, using the CLR profiler to intercept .Net calls at runtime, giving much greater ability to fake objects (not requirements such as needing interfaces or virtual methods).

Unable to install Maven on Windows: "JAVA_HOME is set to an invalid directory"

I was facing the same issue and just updated the JAVA_HOME worked for me.

previously it was like this: C:\Program Files\Java\jdk1.6.0_45\bin Just removed the \bin and it worked for me.

MVC 4 Razor File Upload

View Page

@using (Html.BeginForm("ActionmethodName", "ControllerName", FormMethod.Post, new { id = "formid" }))
   <input type="file" name="file" />
   <input type="submit" value="Upload" class="save" id="btnid" />

script file

$(document).on("click", "#btnid", function (event) {
        var fileOptions = {
            success: res,
            dataType: "json"

In Controller

    public ActionResult UploadFile(HttpPostedFileBase file)


Internet Explorer 11- issue with security certificate error prompt

If you updated Internet Explorer and began having technical problems, you can use the Compatibility View feature to emulate a previous version of Internet Explorer.

For instructions, see the section below that corresponds with your version. To find your version number, click Help > About Internet Explorer. Internet Explorer 11

To edit the Compatibility View list:

Open the desktop, and then tap or click the Internet Explorer icon on the taskbar.
Tap or click the Tools button (Image), and then tap or click Compatibility View settings.
To remove a website:
Click the website(s) where you would like to turn off Compatibility View, clicking Remove after each one.
To add a website:
Under Add this website, enter the website(s) where you would like to turn on Compatibility View, clicking Add after each one.

Excel VBA Open a Folder

I use this to open a workbook and then copy that workbook's data to the template.

Private Sub CommandButton24_Click()
Set Template = ActiveWorkbook
 With Application.FileDialog(msoFileDialogOpen)
    .InitialFileName = "I:\Group - Finance" ' Yu can select any folder you want
    .Title = "Your Title"
    If Not .Show Then
        MsgBox "No file selected.": Exit Sub
    End If
    Workbooks.OpenText .SelectedItems(1)

'The below is to copy the file into a new sheet in the workbook and paste those values in sheet 1

    Set myfile = ActiveWorkbook
    ActiveWorkbook.Sheets(1).Copy after:=ThisWorkbook.Sheets(1)

End With

How to check whether a given string is valid JSON in Java

Here is a working example for strict json parsing with gson library:

public static JsonElement parseStrict(String json) {
    // throws on almost any non-valid json
    return new Gson().getAdapter(JsonElement.class).fromJson(json); 

See also my other detailed answer in How to check if JSON is valid in Java using GSON with more info and extended test case with various non-valid examples.

How to fast-forward a branch to head?

To anyone that wants to Fast Forward they are not on to another remote branch (including itself) without checking out that branch, you can do:

git fetch origin master:other

This basically fast forwards the index of other to origin/master if you are not on other branch. You can fast forward multiple branches this way.

If you working on another branch for some time, and wanted to update stale branches from remote to their respective head:

git fetch origin master:master other:other etc:etc

Ansible - Save registered variable to file

- hosts: all
  - name: Gather Version
     msg: "The server Operating system is {{ ansible_distribution }} {{ ansible_distribution_major_version }}"
  - name: Write  Version
    local_action: shell echo "This is  {{ ansible_distribution }} {{ ansible_distribution_major_version }}" >> /tmp/output

How to determine if .NET Core is installed

You can see which versions of the .NET Core SDK are currently installed with a terminal. Open a terminal and run the following command.

dotnet --list-sdks

How to see log files in MySQL?

The MySQL logs are determined by the global variables such as:

To see the settings and their location, run this shell command:

mysql -se "SHOW VARIABLES" | grep -e log_error -e general_log -e slow_query_log

To print the value of error log, run this command in the terminal:

mysql -e "SELECT @@GLOBAL.log_error"

To read content of the error log file in real time, run:

sudo tail -f $(mysql -Nse "SELECT @@GLOBAL.log_error")

Note: Hit Control-C when finish

When general log is enabled, try:

sudo tail -f $(mysql -Nse "SELECT CONCAT(@@datadir, @@general_log_file)")

To use mysql with the password access, add -p or -pMYPASS parameter. To to keep it remembered, you can configure it in your ~/.my.cnf, e.g.


So it'll be remembered for the next time.

Cannot bulk load because the file could not be opened. Operating System Error Code 3

I did try giving access to the folders but that did not help. My solution was to make the below highlighted options in red selected for the logged in user

This is what you see when you right click and select the username you have logged in for windows authentication mode.

Undefined symbols for architecture i386: _OBJC_CLASS_$_SKPSMTPMessage", referenced from: error

I got this message when I drag and dropped some source files from another project. When I deleted them and then added them via the "Add Files..." from the File menu, it built without the error.

How to tell bash that the line continues on the next line

In general, you can use a backslash at the end of a line in order for the command to continue on to the next line. However, there are cases where commands are implicitly continued, namely when the line ends with a token than cannot legally terminate a command. In that case, the shell knows that more is coming, and the backslash can be omitted. Some examples:

# In general
$ echo "foo" \
> "bar"
foo bar

# Pipes
$ echo foo |
> cat

# && and ||
$ echo foo &&
> echo bar
$ false ||
> echo bar

Different, but related, is the implicit continuation inside quotes. In this case, without a backslash, you are simply adding a newline to the string.

$ x="foo
> bar"
$ echo "$x"

With a backslash, you are again splitting the logical line into multiple logical lines.

$ x="foo\
> bar"
$ echo "$x"

Difference between adjustResize and adjustPan in android?

You can use android:windowSoftInputMode="stateAlwaysHidden|adjustResize" in AndroidManifest.xml for your current activity, and use android:fitsSystemWindows="true" in styles or rootLayout.

How to get the sign, mantissa and exponent of a floating point number

My advice is to stick to rule 0 and not redo what standard libraries already do, if this is enough. Look at math.h (cmath in standard C++) and functions frexp, frexpf, frexpl, that break a floating point value (double, float, or long double) in its significand and exponent part. To extract the sign from the significand you can use signbit, also in math.h / cmath, or copysign (only C++11). Some alternatives, with slighter different semantics, are modf and ilogb/scalbn, available in C++11; compares them, but I didn't find in the documentation how all these functions behave with +/-inf and NaNs. Finally, if you really want to use bitmasks (e.g., you desperately need to know the exact bits, and your program may have different NaNs with different representations, and you don't trust the above functions), at least make everything platform-independent by using the macros in float.h/cfloat.

What does FETCH_HEAD in Git mean?

The FETCH_HEAD is a reference to the tip of the last fetch, whether that fetch was initiated directly using the fetch command or as part of a pull. The current value of FETCH_HEAD is stored in the .git folder in a file named, you guessed it, FETCH_HEAD.

So if I issue:

git fetch

FETCH_HEAD may contain


If I have the remote repo configured as a remote tracking branch then I can follow my fetch with a merge of the tracking branch. If I don't I can merge the tip of the last fetch directly using FETCH_HEAD.

git merge FETCH_HEAD

SQL Group By with an Order By

MySQL prior to version 5 did not allow aggregate functions in ORDER BY clauses.

You can get around this limit with the deprecated syntax:

SELECT COUNT(id), `Tag` from `images-tags`

1, since it's the first column you want to group on.

Changing ViewPager to enable infinite page scrolling

I solved this problem very simply using a little hack in the adapter. Here is my code:

public class MyPagerAdapter extends FragmentStatePagerAdapter
    public static int LOOPS_COUNT = 1000;
    private ArrayList<Product> mProducts;

    public MyPagerAdapter(FragmentManager manager, ArrayList<Product> products)
        mProducts = products;

    public Fragment getItem(int position)
        if (mProducts != null && mProducts.size() > 0)
            position = position % mProducts.size(); // use modulo for infinite cycling
            return MyFragment.newInstance(mProducts.get(position));
            return MyFragment.newInstance(null);

    public int getCount()
        if (mProducts != null && mProducts.size() > 0)
            return mProducts.size()*LOOPS_COUNT; // simulate infinite by big number of products
            return 1;

And then, in the ViewPager, we set current page to the middle:

mAdapter = new MyPagerAdapter(getSupportFragmentManager(), mProducts);
mViewPager.setCurrentItem(mViewPager.getChildCount() * MyPagerAdapter.LOOPS_COUNT / 2, false); // set current item in the adapter to middle

How to generate gcc debug symbol outside the build target?

Check out the "--only-keep-debug" option of the strip command.

From the link:

The intention is that this option will be used in conjunction with --add-gnu-debuglink to create a two part executable. One a stripped binary which will occupy less space in RAM and in a distribution and the second a debugging information file which is only needed if debugging abilities are required.

npm ERR cb() never called

For mac users (HighSierra), do not install node using brew. It'll mess up with npm. I had to uninstall node and install using the package in the main source :

Here's a simple guide that doesn't use brew:

How can I pass a parameter in Action?

If you know what parameter you want to pass, take a Action<T> for the type. Example:

void LoopMethod (Action<int> code, int count) {
     for (int i = 0; i < count; i++) {

If you want the parameter to be passed to your method, make the method generic:

void LoopMethod<T> (Action<T> code, int count, T paramater) {
     for (int i = 0; i < count; i++) {

And the caller code:

Action<string> s = Console.WriteLine;
LoopMethod(s, 10, "Hello World");

Update. Your code should look like:

private void Include(IList<string> includes, Action<string> action)
    if (includes != null)
         foreach (var include in includes)

public void test()
    Action<string> dg = (s) => {
    this.Include(includes, dg);

Documentation for using JavaScript code inside a PDF file

Look for books by Ted Padova. Over the years, he has written a series of books called The Acrobat PDF {5,6,7,8,9...} Bible. They contain chapter(s) on JavaScript in PDF files. They are not as comprehensive as the reference documentation listed here, but in the books there are some realistic use-cases discussed in context.

There was also a talk on hacking PDF files by a computer scientist, given at a conference in 2010. The link on the talk's announcement-page to the slides is dead, but Google is your friend-. The talk is not exclusively on JavaScript, though. YouTube video - JavaScript starts at 06:00.

How do I count unique values inside a list

If you would like to have a histogram of unique values here's oneliner

import numpy as np    
unique_labels, unique_counts = np.unique(labels_list, return_counts=True)
labels_histogram = dict(zip(unique_labels, unique_counts))

Simple dictionary in C++

This is the fastest, simplest, smallest space solution I can think of. A good optimizing compiler will even remove the cost of accessing the pair and name arrays. This solution works equally well in C.

#include <iostream>

enum Base_enum { A, C, T, G };
typedef enum Base_enum Base;
static const Base pair[4] = { T, G, A, C };
static const char name[4] = { 'A', 'C', 'T', 'G' };
static const Base base[85] = 
  { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1,  A, -1,  C, -1, -1,
    -1,  G, -1, -1, -1, -1, -1, -1, -1, -1, 
    -1, -1, -1, -1,  T };

const Base
base2 (const char b)
  switch (b)
    case 'A': return A;
    case 'C': return C;
    case 'T': return T;
    case 'G': return G;
    default: abort ();

main (int argc, char *args) 
  for (Base b = A; b <= G; b++)
      std::cout << name[b] << ":" 
                << name[pair[b]] << std::endl;
  for (Base b = A; b <= G; b++)
      std::cout << name[base[name[b]]] << ":" 
                << name[pair[base[name[b]]]] << std::endl;
  for (Base b = A; b <= G; b++)
      std::cout << name[base2(name[b])] << ":" 
                << name[pair[base2(name[b])]] << std::endl;

base[] is a fast ascii char to Base (i.e. int between 0 and 3 inclusive) lookup that is a bit ugly. A good optimizing compiler should be able to handle base2() but I'm not sure if any do.

AngularJS Multiple ng-app within a page

In my case I had to wrap the bootstrapping of my second app in angular.element(document).ready for it to work:

angular.element(document).ready(function() {
  angular.bootstrap(document.getElementById("app2"), ["app2"]);

when exactly are we supposed to use "public static final String"?

final indicates that the value cannot be changed once set. static allows you to set the value, and that value will be the same for ALL instances of the class which utilize it. Also, you may access the value of a public static string w/o having an instance of a class.

HTML5 Canvas Resize (Downscale) Image High Quality?

DEMO: Resizing images with JS and HTML Canvas Demo fiddler.

You may find 3 different methods to do this resize, that will help you understand how the code is working and why.

Full code of both demo, and TypeScript method that you may want to use in your code, can be found in the GitHub project.

This is the final code:

export class ImageTools {
base64ResizedImage: string = null;

constructor() {

ResizeImage(base64image: string, width: number = 1080, height: number = 1080) {
    let img = new Image();
    img.src = base64image;

    img.onload = () => {

        // Check if the image require resize at all
        if(img.height <= height && img.width <= width) {
            this.base64ResizedImage = base64image;

            // TODO: Call method to do something with the resize image
        else {
            // Make sure the width and height preserve the original aspect ratio and adjust if needed
            if(img.height > img.width) {
                width = Math.floor(height * (img.width / img.height));
            else {
                height = Math.floor(width * (img.height / img.width));

            let resizingCanvas: HTMLCanvasElement = document.createElement('canvas');
            let resizingCanvasContext = resizingCanvas.getContext("2d");

            // Start with original image size
            resizingCanvas.width = img.width;
            resizingCanvas.height = img.height;

            // Draw the original image on the (temp) resizing canvas
            resizingCanvasContext.drawImage(img, 0, 0, resizingCanvas.width, resizingCanvas.height);

            let curImageDimensions = {
                width: Math.floor(img.width),
                height: Math.floor(img.height)

            let halfImageDimensions = {
                width: null,
                height: null

            // Quickly reduce the size by 50% each time in few iterations until the size is less then
            // 2x time the target size - the motivation for it, is to reduce the aliasing that would have been
            // created with direct reduction of very big image to small image
            while (curImageDimensions.width * 0.5 > width) {
                // Reduce the resizing canvas by half and refresh the image
                halfImageDimensions.width = Math.floor(curImageDimensions.width * 0.5);
                halfImageDimensions.height = Math.floor(curImageDimensions.height * 0.5);

                resizingCanvasContext.drawImage(resizingCanvas, 0, 0, curImageDimensions.width, curImageDimensions.height,
                    0, 0, halfImageDimensions.width, halfImageDimensions.height);

                curImageDimensions.width = halfImageDimensions.width;
                curImageDimensions.height = halfImageDimensions.height;

            // Now do final resize for the resizingCanvas to meet the dimension requirments
            // directly to the output canvas, that will output the final image
            let outputCanvas: HTMLCanvasElement = document.createElement('canvas');
            let outputCanvasContext = outputCanvas.getContext("2d");

            outputCanvas.width = width;
            outputCanvas.height = height;

            outputCanvasContext.drawImage(resizingCanvas, 0, 0, curImageDimensions.width, curImageDimensions.height,
                0, 0, width, height);

            // output the canvas pixels as an image. params: format, quality
            this.base64ResizedImage = outputCanvas.toDataURL('image/jpeg', 0.85);

            // TODO: Call method to do something with the resize image

Iterate through every file in one directory

Dir.foreach("/home/mydir") do |fname|
  puts fname

How do I navigate to a parent route from a child route?

Do you want a link/HTML or do you want to route imperatively/in code?

Link: The RouterLink directive always treats the provided link as a delta to the current URL:

[routerLink]="['./child']"     // or

// with route param     ../../parent;abc=xyz
[routerLink]="['../../parent', {abc: 'xyz'}]"
// with query param and fragment   ../../parent?p1=value1&p2=v2#frag
[routerLink]="['../../parent']" [queryParams]="{p1: 'value', p2: 'v2'}" fragment="frag"

With RouterLink, remember to import and use the directives array:

import { ROUTER_DIRECTIVES } from '@angular/router';
    directives: [ROUTER_DIRECTIVES],

Imperative: The navigate() method requires a starting point (i.e., the relativeTo parameter). If none is provided, the navigation is absolute:

import { Router, ActivatedRoute } from '@angular/router';
constructor(private router: Router, private route: ActivatedRoute) {}
this.router.navigate(["../../parent"], {relativeTo: this.route});
this.router.navigate(["../sibling"],   {relativeTo: this.route});
this.router.navigate(["./child"],      {relativeTo: this.route}); // or
this.router.navigate(["child"],        {relativeTo: this.route});

// with route param     ../../parent;abc=xyz
this.router.navigate(["../../parent", {abc: 'xyz'}], {relativeTo: this.route});
// with query param and fragment   ../../parent?p1=value1&p2=v2#frag
this.router.navigate(["../../parent"], {relativeTo: this.route, 
    queryParams: {p1: 'value', p2: 'v2'}, fragment: 'frag'});

// navigate without updating the URL 
this.router.navigate(["../../parent"], {relativeTo: this.route, skipLocationChange: true});

Changing button text onclick

You are missing an opening quote on the id= and you have a semi-colon after the function declaration. Also, the input tag does not need a closing tag.

This works:

<input onclick="change()" type="button" value="Open Curtain" id="myButton1">

<script type="text/javascript">
function change()
document.getElementById("myButton1").value="Close Curtain";

Check date with todays date

another way to do this operation:

public class TimeUtils {

     * @param timestamp
     * @return
    public static boolean isToday(long timestamp) {
        Calendar now = Calendar.getInstance();
        Calendar timeToCheck = Calendar.getInstance();
        return (now.get(Calendar.YEAR) == timeToCheck.get(Calendar.YEAR)
                && now.get(Calendar.DAY_OF_YEAR) == timeToCheck.get(Calendar.DAY_OF_YEAR));


plain count up timer in javascript

I had to create a timer for teachers grading students' work. Here's one I used which is entirely based on elapsed time since the grading begun by storing the system time at the point that the page is loaded, and then comparing it every half second to the system time at that point:

var startTime = Math.floor( / 1000); //Get the starting time (right now) in seconds
localStorage.setItem("startTime", startTime); // Store it if I want to restart the timer on the next page

function startTimeCounter() {
    var now = Math.floor( / 1000); // get the time now
    var diff = now - startTime; // diff in seconds between now and start
    var m = Math.floor(diff / 60); // get minutes value (quotient of diff)
    var s = Math.floor(diff % 60); // get seconds value (remainder of diff)
    m = checkTime(m); // add a leading zero if it's single digit
    s = checkTime(s); // add a leading zero if it's single digit
    document.getElementById("idName").innerHTML = m + ":" + s; // update the element where the timer will appear
    var t = setTimeout(startTimeCounter, 500); // set a timeout to update the timer

function checkTime(i) {
    if (i < 10) {i = "0" + i};  // add zero in front of numbers < 10
    return i;


This way, it really doesn't matter if the 'setTimeout' is subject to execution delays, the elapsed time is always relative the system time when it first began, and the system time at the time of update.

Javascript return number of days,hours,minutes,seconds between two dates

function calculateExamRemainingTime(exam_end_at) {


    const calcNewYear = setInterval(function(){

        const exam_ending_at    = new Date(exam_end_at);
        const current_time      = new Date();
        const totalSeconds     = Math.floor((exam_ending_at - (current_time))/1000);;
        const totalMinutes     = Math.floor(totalSeconds/60);
        const totalHours       = Math.floor(totalMinutes/60);
        const totalDays        = Math.floor(totalHours/24);

        const hours   = totalHours - ( totalDays * 24 );
        const minutes = totalMinutes - ( totalDays * 24 * 60 ) - ( hours * 60 );
        const seconds = totalSeconds - ( totalDays * 24 * 60 * 60 ) - ( hours * 60 * 60 ) - ( minutes * 60 );

        const examRemainingHoursSection = document.querySelector('#remainingHours');
        const examRemainingMinutesSection = document.querySelector('#remainingMinutes');
        const examRemainingSecondsSection = document.querySelector('#remainingSeconds');

        examRemainingHoursSection.innerHTML = hours.toString();
        examRemainingMinutesSection.innerHTML = minutes.toString();
        examRemainingSecondsSection.innerHTML = seconds.toString();


calculateExamRemainingTime('2025-06-03 20:20:20');

How to add an extra language input to Android?

On android 2.2 you can input multiple language and switch by sliding on the spacebar. Go in the settings under "language and keyboard" and then "Android Keyboard", "Input language".

Hope this helps.

Is there any way to call a function periodically in JavaScript?

You will want to have a look at setInterval() and setTimeout().

Here is a decent tutorial article.

How do I fix a Git detached head?

Being in "detached head" means that HEAD refers to a specific unnamed commit (as opposite to a named branch) (cf: section Detached head)

To fix the problem, you only need to select the branch that was selected before by

git checkout @{-1}

How does the SQL injection from the "Bobby Tables" XKCD comic work?

This is how it works: Lets suppose the administrator is looking for records of student


Since the admin account has high privileges deleting the table from this account is possible.

The code to retrieve user name from request is

Now the query would be something like this (to search the student table)

String query="Select * from student where username='"+student_name+"'";

statement.executeQuery(query); //Rest of the code follows

The resultant query becomes

Select * from student where username='Robert'); DROP TABLE STUDENTS; --

Since the user input is not sanitized, The above query has is manipulated into 2 parts

Select * from student where username='Robert'); 


The double dash (--) will just comment out remaining part of the query.

This is dangerous as it can nullify password authentication, if present

The first one will do the normal search.

The second one will drop the table student if the account has sufficient privileges (Generally the school admin account will run such query and will have the privileges talked about above).

How to drop SQL default constraint without knowing its name?

I had some columns that had multiple default constraints created, so I create the following stored procedure:

CREATE PROCEDURE [dbo].[RemoveDefaultConstraints] @table_name nvarchar(256), @column_name nvarchar(256)

    DECLARE @ObjectName NVARCHAR(100)

    START: --Start of loop
        @ObjectName = OBJECT_NAME([default_object_id]) 
        [object_id] = OBJECT_ID(@table_name) 
        AND [name] = @column_name;

    -- Don't drop the constraint unless it exists
    IF @ObjectName IS NOT NULL
        EXEC ('ALTER TABLE '+@table_name+' DROP CONSTRAINT ' + @ObjectName)
        GOTO START; --Used to loop in case of multiple default constraints

-- How to run the stored proc.  This removes the default constraint(s) for the enabled column on the User table.
EXEC [dbo].[RemoveDefaultConstraints] N'[dbo].[User]', N'enabled'

-- If you hate the proc, just get rid of it
DROP PROCEDURE [dbo].[RemoveDefaultConstraints]

HTML table: keep the same width for columns

In your case, since you are only showing 3 columns:

Name    Value       Business
Name    Business    Ecommerce Pro

why not set all 3 to have a width of 33.3%. since only 3 are ever shown at once, the browser should render them all a similar width.

How do I change a tab background color when using TabLayout?

One of the ways I could find is using the tab indicator like this:


    ..... tab items here .....


Trick is to:

  • Make the tab indicator to align in center
  • Make the indicator height sufficiently large so that it covers the whole tab

This also takes care of the smooth animation while switching tabs

How do you make strings "XML safe"?

If at all possible, its always a good idea to create your XML using the XML classes rather than string manipulation - one of the benefits being that the classes will automatically escape characters as needed.

jQuery textbox change event

I have found that this works:

    $('textarea').bind('input propertychange', function() {
        //do your update here


How to automatically import data from uploaded CSV or XLS file into Google Sheets

In case anyone would be searching - I created utility for automated import of xlsx files into google spreadsheet: xls2sheets. One can do it automatically via setting up the cronjob for ./cmd/sheets-refresh, readme describes it all. Hope that would be of use.

When should I use a table variable vs temporary table in sql server?

Microsoft says here

Table variables does not have distribution statistics, they will not trigger recompiles. Therefore, in many cases, the optimizer will build a query plan on the assumption that the table variable has no rows. For this reason, you should be cautious about using a table variable if you expect a larger number of rows (greater than 100). Temp tables may be a better solution in this case.

How do I specify new lines on Python, when writing on files?

Simplest solution

If you only call print without any arguments, it will output a blank line.


You can pipe the output to a file like this (considering your example):

f = open('out.txt', 'w')
print 'First line' >> f
print >> f
print 'Second line' >> f

Not only is it OS-agnostic (without even having to use the os package), it's also more readable than putting \n within strings.


The print() function has an optional keyword argument for the end of the string, called end, which defaults to the OS's newline character, for eg. \n. So, when you're calling print('hello'), Python is actually printing 'hello' + '\n'. Which means that when you're calling just print without any arguments, it's actually printing '' + '\n', which results in a newline.


Use multi-line strings.

s = """First line
    Second line
    Third line"""
f = open('out.txt', 'w')
print s >> f

How to create a hex dump of file containing only the hex characters without spaces in bash?

xxd -p file

Or if you want it all on a single line:

xxd -p file | tr -d '\n'

Should we pass a shared_ptr by reference or by value?

I ran the code below, once with foo taking the shared_ptr by const& and again with foo taking the shared_ptr by value.

void foo(const std::shared_ptr<int>& p)
    static int x = 0;
    *p = ++x;

int main()
    auto p = std::make_shared<int>();
    auto start = clock();
    for (int i = 0; i < 10000000; ++i)
    std::cout << "Took " << clock() - start << " ms" << std::endl;

Using VS2015, x86 release build, on my intel core 2 quad (2.4GHz) processor

const shared_ptr&     - 10ms  
shared_ptr            - 281ms 

The copy by value version was an order of magnitude slower.
If you are calling a function synchronously from the current thread, prefer the const& version.

How to convert DateTime to a number with a precision greater than days in T-SQL?

You can use T-SQL to convert the date before it gets to your .NET program. This often is simpler if you don't need to do additional date conversion in your .NET program.

DECLARE @Date DATETIME = Getdate()
DECLARE @DateInt INT = CONVERT(VARCHAR(30), @Date, 112)
DECLARE @TimeInt INT = REPLACE(CONVERT(VARCHAR(30), @Date, 108), ':', '')
DECLARE @DateTimeInt BIGINT = CONVERT(VARCHAR(30), @Date, 112) + REPLACE(CONVERT(VARCHAR(30), @Date, 108), ':', '')
SELECT @Date as Date, @DateInt DateInt, @TimeInt TimeInt, @DateTimeInt DateTimeInt

Date                    DateInt     TimeInt     DateTimeInt
------------------------- ----------- ----------- --------------------
2013-01-07 15:08:21.680 20130107    150821      20130107150821

What is the best way to exit a function (which has no return value) in python before the function ends (e.g. a check fails)?

  1. return None or return can be used to exit out of a function or program, both does the same thing
  2. quit() function can be used, although use of this function is discouraged for making real world applications and should be used only in interpreter.
    import site
    def func():
  1. exit() function can be used, similar to quit() but the use is discouraged for making real world applications.
import site
    def func():
  1. sys.exit([arg]) function can be used and need to import sys module for that, this function can be used for real world applications unlike the other two functions.
import sys 
  height = 150
if height < 165: # in cm 
    # exits the program 
    sys.exit("Height less than 165")     
    print("You ride the rollercoaster.") 
  1. os._exit(n) function can be used to exit from a process, and need to import os module for that.

How to add a vertical Separator?

<Style x:Key="MySeparatorStyle" TargetType="{x:Type Separator}">
                <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.ControlDarkBrushKey}}"/>
                <Setter Property="Margin" Value="10,0,10,0"/>
                <Setter Property="Focusable" Value="false"/>
                <Setter Property="Template">
                        <ControlTemplate TargetType="{x:Type Separator}">
                                  BorderBrush="{TemplateBinding BorderBrush}" 
                                  BorderThickness="{TemplateBinding BorderThickness}" 
                                  Background="{TemplateBinding Background}" 


<StackPanel  Orientation="Horizontal"  >
           <Separator Style="{StaticResource MySeparatorStyle}" ></Separator>

Fragment onResume() & onPause() is not called on backstack

Follow the below steps, and you shall get the needed answer

1- For both fragments, create a new abstract parent one.
2- Add a custom abstract method that should be implemented by both of them.
3- Call it from the current instance before replacing with the second one.

How to check for palindrome using Python logic

def pali(str1):
    if l1==l:


Is "Id" indexed? If not, that's an important thing to do (I suspect it is already indexed).

Also, do you need to return ALL columns? You may be able to get a substantial improvement in speed if you only actually need a smaller subset of columns which can be FULLY catered for by the index on the ID column - e.g. if you have a NONCLUSTERED index on the Id column, with no other fields included in the index, then it would have to do a lookup on the clustered index to actually get the rest of the columns to return and that could be making up a lot of the cost of the query. If it's a CLUSTERED index, or a NONCLUSTERED index that includes all the other fields you want to return in the query, then you should be fine.

What is the alternative for ~ (user's home directory) on Windows command prompt?

You can use %systemdrive%%homepath% environment variable to accomplish this.

The two command variables when concatenated gives you the desired user's home directory path as below:

  1. Running echo %systemdrive% on command prompt gives:

  2. Running echo %homepath% on command prompt gives:


When used together it becomes:


How to save a Python interactive session?

Also, reinteract gives you a notebook-like interface to a Python session.

css - position div to bottom of containing div

Add position: relative to .outside. (

Elements that are positioned relatively are still considered to be in the normal flow of elements in the document. In contrast, an element that is positioned absolutely is taken out of the flow and thus takes up no space when placing other elements. The absolutely positioned element is positioned relative to nearest positioned ancestor. If a positioned ancestor doesn't exist, the initial container is used.

The "initial container" would be <body>, but adding the above makes .outside positioned.

error: command 'gcc' failed with exit status 1 on CentOS

pip install -U pip
pip install -U cython

Can I make a phone call from HTML on Android?

Generally on Android, if you simply display the phone number, and the user taps on it, it will pull it up in the dialer. So, you could simply do

For more information, call us at <b>416-555-1234</b>

When the user taps on the bold part, since it's formatted like a phone number, the dialer will pop up, and show 4165551234 in the phone number field. The user then just has to hit the call button.

You might be able to do

For more information, call us at <a href='tel:416-555-1234'>416-555-1234</a>

to cover both devices, but I'm not sure how well this would work. I'll give it a try shortly and let you know.

EDIT: I just gave this a try on my HTC Magic running a rooted Rogers 1.5 with SenseUI:

For more information, call us at <a href='tel:416-555-1234'>416-555-1234</a><br />
<br />
Call at <a href='tel:416-555-1234'>our number</a>
<br />
<br />
<a href='416-555-1234'>Blah</a>
<br />
<br />
For more info, call <b>416-555-1234</b>

The first one, surrounding with the link and printing the phone number, worked perfectly. Pulled up the dialer with the hyphens and all. The second, saying our number with the link, worked exactly the same. This means that using <a href='tel:xxx-xxx-xxxx'> should work across the board, but I wouldn't suggest taking my one test as conclusive.

Linking straight to the number did the expected: Tried to pull up the nonexistent file from the server.

The last one did as I mentioned above, and pulled up the dialer, but without the nice formatting hyphens.

Measuring execution time of a function in C++

Here is an excellent header only class template to measure the elapsed time of a function or any code block:


template<class Resolution = std::chrono::milliseconds>
class ExecutionTimer {
    using Clock = std::conditional_t<std::chrono::high_resolution_clock::is_steady,
    const Clock::time_point mStart = Clock::now();

    ExecutionTimer() = default;
    ~ExecutionTimer() {
        const auto end = Clock::now();
        std::ostringstream strStream;
        strStream << "Destructor Elapsed: "
                  << std::chrono::duration_cast<Resolution>( end - mStart ).count()
                  << std::endl;
        std::cout << strStream.str() << std::endl;

    inline void stop() {
        const auto end = Clock::now();
        std::ostringstream strStream;
        strStream << "Stop Elapsed: "
                  << std::chrono::duration_cast<Resolution>(end - mStart).count()
                  << std::endl;
        std::cout << strStream.str() << std::endl;

}; // ExecutionTimer


Here are some uses of it:

int main() {
    { // empty scope to display ExecutionTimer's destructor's message
         // displayed in milliseconds
         ExecutionTimer<std::chrono::milliseconds> timer;

         // function or code block here



    { // same as above
        ExecutionTimer<std::chrono::microseconds> timer;

        // code block here...


    {  // same as above
       ExecutionTimer<std::chrono::nanoseconds> timer;

       // code block here...



    {  // same as above
       ExecutionTimer<std::chrono::seconds> timer;

       // code block here...



    return 0;

Since the class is a template we can specify real easily in how we want our time to be measured & displayed. This is a very handy utility class template for doing bench marking and is very easy to use.

Oracle SQL - select within a select (on the same table!)

SELECT eh."Gc_Staff_Number",
       MAX(eh2."End_Date") AS "End_Date"
FROM   "Employment_History" eh
LEFT JOIN  "Employment_History" eh2
ON eh."Employee_Number" = eh2."Employee_Number" and eh2."Current_Flag" != 'Y'
WHERE  eh."Current_Flag" = 'Y' 
GROUP BY eh."Gc_Staff_Number",

Must declare the scalar variable

Case Sensitivity will cause this problem, too.

@MyVariable and @myvariable are the same variables in SQL Server Man. Studio and will work. However, these variables will result in a "Must declare the scalar variable "@MyVariable" in Visual Studio (C#) due to case-sensitivity differences.

How to remove .html from URL?

For those who are using Firebase hosting none of the answers will work on this page. Because you can't use .htaccess in Firebase hosting. You will have to configure the firebase.json file. Just add the line "cleanUrls": true in your file and save it. That's it.

After adding the line firebase.json will look like this :

  "hosting": {
    "public": "public",
    "cleanUrls": true, 
    "ignore": [

How to find list intersection?

Here's some Python 2 / Python 3 code that generates timing information for both list-based and set-based methods of finding the intersection of two lists.

The pure list comprehension algorithms are O(n^2), since in on a list is a linear search. The set-based algorithms are O(n), since set search is O(1), and set creation is O(n) (and converting a set to a list is also O(n)). So for sufficiently large n the set-based algorithms are faster, but for small n the overheads of creating the set(s) make them slower than the pure list comp algorithms.

#!/usr/bin/env python

''' Time list- vs set-based list intersection
    Written by PM 2Ring 2015.10.16

from __future__ import print_function, division
from timeit import Timer

setup = 'from __main__ import a, b'
cmd_lista = '[u for u in a if u in b]'
cmd_listb = '[u for u in b if u in a]'

cmd_lcsa = 'sa=set(a);[u for u in b if u in sa]'

cmd_seta = 'list(set(a).intersection(b))'
cmd_setb = 'list(set(b).intersection(a))'

reps = 3
loops = 50000

def do_timing(heading, cmd, setup):
    t = Timer(cmd, setup)
    r = t.repeat(reps, loops)
    print(heading, r)
    return r[0]

m = 10
nums = list(range(6 * m))

for n in range(1, m + 1):
    a = nums[:6*n:2]
    b = nums[:6*n:3]
    print('\nn =', n, len(a), len(b))
    #print('\nn = %d\n%s %d\n%s %d' % (n, a, len(a), b, len(b)))
    la = do_timing('lista', cmd_lista, setup) 
    lb = do_timing('listb', cmd_listb, setup) 
    lc = do_timing('lcsa ', cmd_lcsa, setup)
    sa = do_timing('seta ', cmd_seta, setup)
    sb = do_timing('setb ', cmd_setb, setup)
    print(la/sa, lb/sa, lc/sa, la/sb, lb/sb, lc/sb)


n = 1 3 2
lista [0.082171916961669922, 0.082588911056518555, 0.0898590087890625]
listb [0.069530963897705078, 0.070394992828369141, 0.075379848480224609]
lcsa  [0.11858987808227539, 0.1188349723815918, 0.12825107574462891]
seta  [0.26900982856750488, 0.26902294158935547, 0.27298116683959961]
setb  [0.27218389511108398, 0.27459001541137695, 0.34307217597961426]
0.305460649521 0.258469975867 0.440838458259 0.301898526833 0.255455833892 0.435697630214

n = 2 6 4
lista [0.15915989875793457, 0.16000485420227051, 0.16551494598388672]
listb [0.13000702857971191, 0.13060092926025391, 0.13543915748596191]
lcsa  [0.18650484085083008, 0.18742108345031738, 0.19513416290283203]
seta  [0.33592700958251953, 0.34001994132995605, 0.34146714210510254]
setb  [0.29436492919921875, 0.2953648567199707, 0.30039691925048828]
0.473793098554 0.387009751735 0.555194537893 0.540689066428 0.441652573672 0.633583767462

n = 3 9 6
lista [0.27657914161682129, 0.28098297119140625, 0.28311991691589355]
listb [0.21585917472839355, 0.21679902076721191, 0.22272896766662598]
lcsa  [0.22559309005737305, 0.2271728515625, 0.2323150634765625]
seta  [0.36382699012756348, 0.36453008651733398, 0.36750602722167969]
setb  [0.34979605674743652, 0.35533690452575684, 0.36164689064025879]
0.760194128313 0.59330170819 0.62005595016 0.790686848184 0.61710008036 0.644927481902

n = 4 12 8
lista [0.39616990089416504, 0.39746403694152832, 0.41129183769226074]
listb [0.33485794067382812, 0.33914685249328613, 0.37850618362426758]
lcsa  [0.27405810356140137, 0.2745978832244873, 0.28249192237854004]
seta  [0.39211201667785645, 0.39234519004821777, 0.39317893981933594]
setb  [0.36988520622253418, 0.37011313438415527, 0.37571001052856445]
1.01034878821 0.85398540833 0.698928091731 1.07106176249 0.905302334456 0.740927452493

n = 5 15 10
lista [0.56792402267456055, 0.57422614097595215, 0.57740211486816406]
listb [0.47309303283691406, 0.47619009017944336, 0.47628307342529297]
lcsa  [0.32805585861206055, 0.32813096046447754, 0.3349759578704834]
seta  [0.40036201477050781, 0.40322518348693848, 0.40548801422119141]
setb  [0.39103078842163086, 0.39722800254821777, 0.43811702728271484]
1.41852623806 1.18166313332 0.819398061028 1.45237674242 1.20986133789 0.838951479847

n = 6 18 12
lista [0.77897095680236816, 0.78187918663024902, 0.78467702865600586]
listb [0.629547119140625, 0.63210701942443848, 0.63321495056152344]
lcsa  [0.36563992500305176, 0.36638498306274414, 0.38175487518310547]
seta  [0.46695613861083984, 0.46992206573486328, 0.47583580017089844]
setb  [0.47616910934448242, 0.47661614418029785, 0.4850609302520752]
1.66818870637 1.34819326075 0.783028414812 1.63591241329 1.32210827369 0.767878297495

n = 7 21 14
lista [0.9703209400177002, 0.9734041690826416, 1.0182771682739258]
listb [0.82394003868103027, 0.82625699043273926, 0.82796716690063477]
lcsa  [0.40975093841552734, 0.41210508346557617, 0.42286920547485352]
seta  [0.5086359977722168, 0.50968098640441895, 0.51014018058776855]
setb  [0.48688101768493652, 0.4879908561706543, 0.49204087257385254]
1.90769222837 1.61990115188 0.805587768483 1.99293236904 1.69228211566 0.841583309951

n = 8 24 16
lista [1.204819917678833, 1.2206029891967773, 1.258256196975708]
listb [1.014998197555542, 1.0206191539764404, 1.0343101024627686]
lcsa  [0.50966787338256836, 0.51018595695495605, 0.51319599151611328]
seta  [0.50310111045837402, 0.50556015968322754, 0.51335406303405762]
setb  [0.51472997665405273, 0.51948785781860352, 0.52113485336303711]
2.39478683834 2.01748351664 1.01305257092 2.34068341135 1.97190418975 0.990165516871

n = 9 27 18
lista [1.511646032333374, 1.5133969783782959, 1.5639569759368896]
listb [1.2461750507354736, 1.254518985748291, 1.2613379955291748]
lcsa  [0.5565330982208252, 0.56119203567504883, 0.56451296806335449]
seta  [0.5966339111328125, 0.60275578498840332, 0.64791703224182129]
setb  [0.54694414138793945, 0.5508568286895752, 0.55375313758850098]
2.53362406013 2.08867620074 0.932788243907 2.76380331728 2.27843203069 1.01753187594

n = 10 30 20
lista [1.7777848243713379, 2.1453688144683838, 2.4085969924926758]
listb [1.5070111751556396, 1.5202279090881348, 1.5779800415039062]
lcsa  [0.5954139232635498, 0.59703707695007324, 0.60746097564697266]
seta  [0.61563014984130859, 0.62125110626220703, 0.62354087829589844]
setb  [0.56723213195800781, 0.57257509231567383, 0.57460403442382812]
2.88774814689 2.44791645689 0.967161734066 3.13413984189 2.6567803378 1.04968299523

Generated using a 2GHz single core machine with 2GB of RAM running Python 2.6.6 on a Debian flavour of Linux (with Firefox running in the background).

These figures are only a rough guide, since the actual speeds of the various algorithms are affected differently by the proportion of elements that are in both source lists.

Programmatically change input type of the EditText from PASSWORD to NORMAL & vice versa

For kotlin users:

password.inputType = InputType.TYPE_CLASS_TEXT or InputType.TYPE_TEXT_VARIATION_PASSWORD

git remove merge commit from history

To Just Remove a Merge Commit

If all you want to do is to remove a merge commit (2) so that it is like it never happened, the command is simply as follows

git rebase --onto <sha of 1> <sha of 2> <blue branch>

And now the purple branch isn't in the commit log of blue at all and you have two separate branches again. You can then squash the purple independently and do whatever other manipulations you want without the merge commit in the way.

angular2 manually firing click event on particular element

To get the native reference to something like an ion-input, ry using this

@ViewChild('fileInput', { read: ElementRef }) fileInput: ElementRef;

and then


CSS to hide INPUT BUTTON value text

I use

button {text-indent:-9999px;}
* html button{font-size:0;display:block;line-height:0}  /* ie6 */
*+html button{font-size:0;display:block;line-height:0}  /* ie7 */

how to upload file using curl with php


if (function_exists('curl_file_create')) { // php 5.5+
  $cFile = curl_file_create($file_name_with_full_path);
} else { // 
  $cFile = '@' . realpath($file_name_with_full_path);
$post = array('extra_info' => '123456','file_contents'=> $cFile);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,$target_url);
curl_setopt($ch, CURLOPT_POST,1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post);
$result=curl_exec ($ch);
curl_close ($ch);

You can also refer:

Important hint for PHP 5.5+:

Now we should use but if you still want to use this deprecated approach then you need to set curl_setopt($ch, CURLOPT_SAFE_UPLOAD, false);

Adding click event for a button created dynamically using jQuery

Question 1: Use .delegate on the div to bind a click handler to the button.

Question 2: Use $(this).val() or this.value (the latter would be faster) inside of the click handler. this will refer to the button.

$("#pg_menu_content").on('click', '#btn_a', function () {

$div = $('<div data-role="fieldcontain"/>');
$("<input type='button' value='Dynamic Button' id='btn_a' />").appendTo($div.clone()).appendTo('#pg_menu_content');

How to deep copy a list?

This is more pythonic

my_list = [0, 1, 2, 3, 4, 5]  # some list
my_list_copy = list(my_list)  # my_list_copy and my_list does not share reference now.

NOTE: This is not safe with a list of referenced objects

Remove git mapping in Visual Studio 2015

I spent some time to remove the git integration from my visual studio 2015 project. any time i remove git from visual studio, and add TFS by following this -- Tools -> option -> sourceControl -> plugin selection -> Visual Studio Team foundation server, it used to come back.

My solution was -

making the physical location of my project- Show all hidden files. you can do this by show hidden files and folder option of windows. then i realize, there was a hidden folder called .git something. I kept a full back up of my project folder and also the git folder any other back up that necessary (I kept this back up incase my project breaks, so that i can go back to previous condition).

then i have deleted the hidden .git folder and any other .git related files.

then i try to Tools -> option -> sourceControl -> plugin selection -> Visual Studio Team foundation server. then i open the project by visual studio- File -> open -> project/solution..

after that i noiticed in solution explorer , right clicking the solution namei see "Source control" option , and also in project - right click i see "Add soution to source control".. and this time it didn't add solution to git..

also it is good to remove any git connection from your source control exploerer..if there is any..

so the main thing is that make sure there is no hidden git file in your project file and any other git extension.. hope this will be helpful to someone..

Transport endpoint is not connected

So interestingly enough this error "Transport endpoint is not connected" was caused by my having more than one Veracrypt device mounted. I closed the extra device and suddenly I had access to the drive. Hmm..

Why do many examples use `fig, ax = plt.subplots()` in Matplotlib/pyplot/python

In addition to the answers above, you can check the type of object using type(plt.subplots()) which returns a tuple, on the other hand, type(plt.subplot()) returns matplotlib.axes._subplots.AxesSubplot which you can't unpack.

Byte Array to Hex String

Consider the hex() method of the bytes type on Python 3.5 and up:

>>> array_alpha = [ 133, 53, 234, 241 ]
>>> print(bytes(array_alpha).hex())

EDIT: it's also much faster than hexlify (modified @falsetru's benchmarks above)

from timeit import timeit
N = 10000
print("bytearray + hexlify ->", timeit(
    setup='import binascii; data = bytearray(range(255))',
print("byte + hex          ->", timeit(
    setup='data = bytes(range(255))',


bytearray + hexlify -> 0.011218150997592602
byte + hex          -> 0.005952142993919551

slf4j: how to log formatted message, object array, exception

As of SLF4J 1.6.0, in the presence of multiple parameters and if the last argument in a logging statement is an exception, then SLF4J will presume that the user wants the last argument to be treated as an exception and not a simple parameter. See also the relevant FAQ entry.

So, writing (in SLF4J version 1.7.x and later)

 logger.error("one two three: {} {} {}", "a", "b", 
              "c", new Exception("something went wrong"));

or writing (in SLF4J version 1.6.x)

 logger.error("one two three: {} {} {}", new Object[] {"a", "b", 
              "c", new Exception("something went wrong")});

will yield

one two three: a b c
java.lang.Exception: something went wrong
    at Example.main(
    at java.lang.reflect.Method.invoke(
    at ...

The exact output will depend on the underlying framework (e.g. logback, log4j, etc) as well on how the underlying framework is configured. However, if the last parameter is an exception it will be interpreted as such regardless of the underlying framework.

How to submit a form using Enter key in react.js?

It's been quite a few years since this question was last answered. React introduced "Hooks" back in 2017, and "keyCode" has been deprecated.

Now we can write this:

  useEffect(() => {
    const listener = event => {
      if (event.code === "Enter" || event.code === "NumpadEnter") {
        console.log("Enter key was pressed. Run your function.");
        // callMyFunction();
    document.addEventListener("keydown", listener);
    return () => {
      document.removeEventListener("keydown", listener);
  }, []);

This registers a listener on the keydown event, when the component is loaded for the first time. It removes the event listener when the component is destroyed.

How to change webservice url endpoint?

To change the end address property edit your wsdl file

  <wsdl:service name="serviceMethodName">
    <wsdl:port binding="tns:serviceMethodNameSoapBinding" name="serviceMethodName">
      <soap:address location="http://service_end_point_adress"/>

Refresh Part of Page (div)

$.ajax(), $.get(), $.post(), $.load() functions of jQuery internally send XML HTTP request. among these the load() is only dedicated for a particular DOM Element. See jQuery Ajax Doc. A details Q.A. on these are Here .

Finding all cycles in a directed graph

DFS c++ version for the pseudo-code in second floor's answer:

void findCircleUnit(int start, int v, bool* visited, vector<int>& path) {
    if(visited[v]) {
        if(v == start) {
            for(auto c : path)
                cout << c << " ";
            cout << endl;
    visited[v] = true;
    for(auto i : G[v])
        findCircleUnit(start, i, visited, path);
    visited[v] = false;

How to get jQuery to wait until an effect is finished?

if its something you wish to switch, fading one out and fading another in the same place, you can place a {position:absolute} attribute on the divs, so both the animations play on top of one another, and you don't have to wait for one animation to be over before starting up the next.

Push method in React Hooks (useState)?

When you use useState, you can get an update method for the state item:

const [theArray, setTheArray] = useState(initialArray);

then, when you want to add a new element, you use that function and pass in the new array or a function that will create the new array. Normally the latter, since state updates are asynchronous and sometimes batched:

setTheArray(oldArray => [...oldArray, newElement]);

Sometimes you can get away without using that callback form, if you only update the array in handlers for certain specific user events like click (but not like mousemove):

setTheArray([...theArray, newElement]);

The events for which React ensures that rendering is flushed are the "discrete events" listed here.

Live Example (passing a callback into setTheArray):

const {useState, useCallback} = React;
function Example() {
    const [theArray, setTheArray] = useState([]);
    const addEntryClick = () => {
        setTheArray(oldArray => [...oldArray, `Entry ${oldArray.length}`]);
    return [
        <input type="button" onClick={addEntryClick} value="Add" />,
        <div>{ =>

    <Example />,
<div id="root"></div>
<script src=""></script>
<script src=""></script>

Because the only update to theArray in there is the one in a click event (one of the "discrete" events), I could get away with a direct update in addEntry:

const {useState, useCallback} = React;
function Example() {
    const [theArray, setTheArray] = useState([]);
    const addEntryClick = () => {
        setTheArray([...theArray, `Entry ${theArray.length}`]);
    return [
        <input type="button" onClick={addEntryClick} value="Add" />,
        <div>{ =>

    <Example />,
<div id="root"></div>
<script src=""></script>
<script src=""></script>

Change Git repository directory location.

Although the previous answers all seem to say that you can just move the directory and there are no absolute paths in the .git structure. I found this to be untrue when using git from Cygwin.

When I moved my git repo (in fact I restored it from a backup, but to a different drive as my drive structure changed on my new system). I got an error message like

fatal: Invalid path '<part_of_the_original_repo_path>': No such file or directory

I used grep to find that in my .git/config file in the [core] section is a worktree variable which holds the absolute path of my git repo. Changing this fixed the problem for me.

Finding whether a point lies inside a rectangle or not

I realise this is an old thread, but for anyone who's interested in looking at this from a purely mathematical perspective, there's an excellent thread on the maths stack exchange, here:

Edit: Inspired by this thread, I've put together a simple vector method for quickly determining where your point lies.

Suppose you have a rectangle with points at p1 = (x1, y1), p2 = (x2, y2), p3 = (x3, y3) and p4 = (x4, y4), going clockwise. If a point p = (x, y) lies inside the rectangle, then the dot product (p - p1).(p2 - p1) will lie between 0 and |p2 - p1|^2, and (p - p1).(p4 - p1) will lie between 0 and |p4 - p1|^2. This is equivalent to taking the projection of the vector p - p1 along the length and width of the rectangle, with p1 as the origin.

This may make more sense if I show an equivalent code:

p21 = (x2 - x1, y2 - y1)
p41 = (x4 - x1, y4 - y1)

p21magnitude_squared = p21[0]^2 + p21[1]^2
p41magnitude_squared = p41[0]^2 + p41[1]^2

for x, y in list_of_points_to_test:

    p = (x - x1, y - y1)

    if 0 <= p[0] * p21[0] + p[1] * p21[1] <= p21magnitude_squared:
        if 0 <= p[0] * p41[0] + p[1] * p41[1]) <= p41magnitude_squared:
            return "Inside"
            return "Outside"
        return "Outside"

And that's it. It will also work for parallelograms.

How to generate access token using refresh token through google drive API?

If you are using web api then you should make a http POST call to URL : with following request body

client_id: <YOUR_CLIENT_ID>
client_secret: <YOUR_CLIENT_SECRET>
grant_type: refresh_token

refresh token never expires so you can use it any number of times. The response will be a JSON like this:

  "access_token": "your refreshed access token",
  "expires_in": 3599,
  "scope": "Set of scope which you have given",
  "token_type": "Bearer"

How to resolve ORA-011033: ORACLE initialization or shutdown in progress

What worked for me is that i hadn't set the local_listener, to see if the local listener is set login to sqlplus / as sysdba, make sure the database is open and run the following command show parameter local_listener, if the value is empty, then you will have to set the local_listener with the following SQL command ALTER SYSTEM SET LOCAL_LISTENER='<LISTENER_NAME_GOES_HERE>'

How to deal with "java.lang.OutOfMemoryError: Java heap space" error?

I read somewhere else that you can try - catch java.lang.OutOfMemoryError and on the catch block, you can free all resources that you know might use a lot of memory, close connections and so forth, then do a System.gc() then re-try whatever you were going to do.

Another way is this although, i don't know whether this would work, but I am currently testing whether it will work on my application.

The Idea is to do Garbage collection by calling System.gc() which is known to increase free memory. You can keep checking this after a memory gobbling code executes.

//Mimimum acceptable free memory you think your app needs
long minRunningMemory = (1024*1024);

Runtime runtime = Runtime.getRuntime();


How to return only 1 row if multiple duplicate rows and still return rows that are not duplicates?

select * from temptable
where rnum --unique key

 SELECT RNUM --unique key
  FROM temptable
 WHERE (  HistoryStatus
) IN (SELECT                HistoryStatus

                             FROM temptable
                            GROUP BY                
                           HAVING COUNT(*) <= 1));

I have not tested this code. I have used similar code and it works. The syntax is in Oracle.

Undefined symbols for architecture arm64

If your Architectures and Valid Architectures are all right, you may check whether you have added $(inherited) , which will add linker flags generated in pods, to Other Linker Flags as below: enter image description here

How do I compare 2 rows from the same table (SQL Server)?

Some people find the following alternative syntax easier to see what is going on:

select t1.value,t2.value
from MyTable t1
    inner join MyTable t2 on =
where = @id

How to add a hook to the application context initialization event?

I had a single page application on entering URL it was creating a HashMap (used by my webpage) which contained data from multiple databases. I did following things to load everything during server start time-

1- Created ContextListenerClass

public class MyAppContextListener implements ServletContextListener

    private  MyDataProviderBean myDataProviderBean; 

    public MyDataProviderBean getMyDataProviderBean() {

        return MyDataProviderBean;


    public void setMyDataProviderBean(MyDataProviderBean MyDataProviderBean) {

        this.myDataProviderBean = MyDataProviderBean;


    public void contextDestroyed(ServletContextEvent arg0) {

        System.out.println("ServletContextListener destroyed");



    public void contextInitialized(ServletContextEvent context) {

        System.out.println("ServletContextListener started");

        ServletContext sc = context.getServletContext();

        WebApplicationContext springContext = WebApplicationContextUtils.getWebApplicationContext(sc);

        MyDataProviderBean MyDataProviderBean = (MyDataProviderBean)springContext.getBean("myDataProviderBean");

        Map<String, Object> myDataMap = MyDataProviderBean.getDataMap();

        sc.setAttribute("myMap", myDataMap);


2- Added below entry in web.xml


3- In my Controller Class updated code to first check for Map in servletContext

    @RequestMapping(value = "/index", method = RequestMethod.GET)
        public String index(@ModelAttribute("model") ModelMap model) {

            Map<String, Object> myDataMap = new HashMap<String, Object>();
            if (context != null && context.getAttribute("myMap")!=null)

                myDataMap=(Map<String, Object>)context.getAttribute("myMap");


                myDataMap = myDataProviderBean.getDataMap();

            for (String key : myDataMap.keySet())
                model.addAttribute(key, myDataMap.get(key));
            return "myWebPage";


With this much change when I start my tomcat it loads dataMap during startTime and puts everything in servletContext which is then used by Controller Class to get results from already populated servletContext .

Interesting 'takes exactly 1 argument (2 given)' Python error

Summary (Some examples of how to define methods in classes in python)

#!/usr/bin/env python   # (if running from bash)

class Class1(object):

    def A(self, arg1):
        print arg1
        # this method requires an instance of Class1   
        # can access self.variable_name, and other methods in Class1

    def B(cls, arg1):
        # can access methods B and C in Class1 

    def C(arg1):
        print arg1
        # can access methods B and C in Class1 
        # (i.e. via Class1.B(...) and Class1.C(...))



# Class1.A("2") # TypeError: method A() must be called with Class1 instance


Prevent textbox autofill with previously entered values

Please note that for Chrome to work properly it needs to be autocomplete="false"

Use images instead of radio buttons

Here is very simple example

input[type="radio"] + label_x000D_
    background-size: 100px 100px;_x000D_
    height: 100px;_x000D_
    width: 100px;_x000D_
    padding: 0 0 0 0px;_x000D_
input[type="radio"]:checked + label_x000D_
  <input type="radio" id="shipadd1" value=1 name="address" />_x000D_
  <label for="shipadd1"></label>_x000D_
  value 1_x000D_
  <input type="radio" id="shipadd2" value=2 name="address" />_x000D_
  <label for="shipadd2"></label>_x000D_
  value 2_x000D_


This example based on this trick:

I tested it on: chrome, firefox, safari

What does %s and %d mean in printf in the C language?

The first argument to printf is a string of identifiers.

%s refers to a string %d refers to an integer %c refers to a character. Therefore: %s%d%s%c\n prints the string "The first character in sting ", %d prints i, %s prints " is ", and %c prints str[0].

How to create/make rounded corner buttons in WPF?

I know its a old question but if you are looking to make the button on c# instead of xaml you can set the CornerRadius that will round your button.

Button buttonRouded = new Button
   CornerRadius = 10,

how to open .mat file without using MATLAB?

Download Notepad++ ( it opens nearly any file format and recognizes breaks, comments and does all the same color coding as the original language formatting.

How to change the background colour's opacity in CSS

Use RGB values combined with opacity to get the transparency that you wish.

For instance,

<div style=" background: rgb(255, 0, 0) ; opacity: 0.2;">&nbsp;</div>
<div style=" background: rgb(255, 0, 0) ; opacity: 0.4;">&nbsp;</div>
<div style=" background: rgb(255, 0, 0) ; opacity: 0.6;">&nbsp;</div>
<div style=" background: rgb(255, 0, 0) ; opacity: 0.8;">&nbsp;</div>
<div style=" background: rgb(255, 0, 0) ; opacity: 1;">&nbsp;</div>

Similarly, with actual values without opacity, will give the below.

<div style=" background: rgb(243, 191, 189) ; ">&nbsp;</div>
<div style=" background: rgb(246, 143, 142) ; ">&nbsp;</div>
<div style=" background: rgb(249, 95 , 94)  ; ">&nbsp;</div>
<div style=" background: rgb(252, 47, 47)   ; ">&nbsp;</div>
<div style=" background: rgb(255, 0, 0)     ; ">&nbsp;</div>

You can have a look at this WORKING EXAMPLE.

Now, if we specifically target your issue, here is the WORKING DEMO SPECIFIC TO YOUR ISSUE.


<div class="social">
    <img src="" border="0" />

The CSS:

social img{
.social img:hover {
    background: rgb(255, 0, 0) ; opacity: 0.5;

Hope this helps Now.

How to Delete Session Cookie?

This needs to be done on the server-side, where the cookie was issued.

What does "dereferencing" a pointer mean?

I think all the previous answers are wrong, as they state that dereferencing means accessing the actual value. Wikipedia gives the correct definition instead:

It operates on a pointer variable, and returns an l-value equivalent to the value at the pointer address. This is called "dereferencing" the pointer.

That said, we can dereference the pointer without ever accessing the value it points to. For example:

char *p = NULL;

We dereferenced the NULL pointer without accessing its value. Or we could do:

p1 = &(*p);
sz = sizeof(*p);

Again, dereferencing, but never accessing the value. Such code will NOT crash: The crash happens when you actually access the data by an invalid pointer. However, unfortunately, according the the standard, dereferencing an invalid pointer is an undefined behaviour (with a few exceptions), even if you don't try to touch the actual data.

So in short: dereferencing the pointer means applying the dereference operator to it. That operator just returns an l-value for your future use.

LEFT function in Oracle

I've discovered that LEFT and RIGHT are not supported functions in Oracle. They are used in SQL Server, MySQL, and some other versions of SQL. In Oracle, you need to use the SUBSTR function. Here are simple examples:

LEFT ('Data', 2) = 'Da'

->   SUBSTR('Data',1,2) = 'Da'

RIGHT ('Data', 2) = 'ta'

->   SUBSTR('Data',-2,2) = 'ta'

Notice that a negative number counts back from the end.

Getting all names in an enum as a String[]

Basing off from Bohemian's answer for Kotlin:

Use replace() instead of replaceAll().

Arrays.toString(MyEnum.values()).replace(Regex("^.|.$"), "").split(", ").toTypedArray()

Side note: Convert to .toTypedArray() for use in AlertDialog's setSingleChoiceItems, for example.

How to display Base64 images in HTML?

you can put your data directly in a url statment like

src = 'url(imageData)' ;

and to get the image data u can use the php function

$imageContent = file_get_contents("imageDir/".$imgName);

$imageData = base64_encode($imageContent);

so you can copy paste the value of imageData and paste it directly to your url and assign it to the src attribute of your image

Output a NULL cell value in Excel

As you've indicated, you can't output NULL in an excel formula. I think this has to do with the fact that the formula itself causes the cell to not be able to be NULL. "" is the next best thing, but sometimes it's useful to use 0.


Based on your comment, you might want to check out this link.

It goes in depth on the graphing issues and what the various values represent, and how to manipulate their output on a chart.

I'm not familiar with VSTO I'm afraid. So I won't be much help there. But if you are really placing formulas in the cell, then there really is no way. ISBLANK() only tests to see if a cell is blank or not, it doesn't have a way to make it blank. It's possible to write code in VBA (and VSTO I imagine) that would run on a worksheet_change event and update the various values instead of using formulas. But that would be cumbersome and performance would take a hit.

ansible: lineinfile for several lines?

I was able to do that by using \n in the line parameter.

It is specially useful if the file can be validated, and adding a single line generates an invalid file.

In my case, I was adding AuthorizedKeysCommand and AuthorizedKeysCommandUser to sshd_config, with the following command:

- lineinfile: dest=/etc/ssh/sshd_config line='AuthorizedKeysCommand /etc/ssh/ldap-keys\nAuthorizedKeysCommandUser nobody' validate='/usr/sbin/sshd -T -f %s'

Adding only one of the options generates a file that fails validation.

How to iterate through table in Lua?

To iterate over all the key-value pairs in a table you can use pairs:

for k, v in pairs(arr) do
  print(k, v[1], v[2], v[3])


pears   2   p   green
apples  0   a   red
oranges 1   o   orange

Edit: Note that Lua doesn't guarantee any iteration order for the associative part of the table. If you want to access the items in a specific order, retrieve the keys from arr and sort it. Then access arr through the sorted keys:

local ordered_keys = {}

for k in pairs(arr) do
    table.insert(ordered_keys, k)

for i = 1, #ordered_keys do
    local k, v = ordered_keys[i], arr[ ordered_keys[i] ]
    print(k, v[1], v[2], v[3])


  apples  a   red     5
  oranges o   orange  12
  pears   p   green   7

jQuery removing '-' character from string

If you want to remove all - you can use:

.replace(new RegExp('-', 'g'),"")

The OLE DB provider "Microsoft.ACE.OLEDB.12.0" for linked server "(null)"

There are two crucial nonobvious settings that I've discovered when tuning linked servers on Excel under SQL Server 2014. With those settings, ' FROM OPENDATASOURCE(''Microsoft.ACE.OLEDB.16.0'', ...)' as well as '... FROM [' + @srv_name + '] AS xl ...' function properly.

Linked server creation

This is just for context.

DECLARE @srv_name nvarchar(64) = N'<srv_base_name>@' + @DB_NAME; --to distinguish linked server usage by different databases

EXEC sp_addlinkedserver
    @srvproduct=N'OLE DB Provider for ACE 16.0',
    @provider= N'Microsoft.ACE.OLEDB.16.0',
    @datasrc= '<local_file_path>\<excel_workbook_name>.xlsx',
    @provstr= N'Excel 12.0;HDR=YES;IMEX=0'
  1. @datasrc: Encoding is crucial here: varchar instead of nvarchar.
  2. @provstr: Verion, settings and sytax are important!
  3. @provider: Specify the provider installed in your SQL Server environment. Available providers are enumerated under Server Objects::Linked Servers::Providers in SSMS's Object Explorer.

Providing access to the linked server under specific SQL Server logins

This is the first crucial setting. Even for SA like for any other SQL Server login:

EXEC sp_addlinkedsrvlogin @rmtsrvname = @srv_name, @locallogin = N'sa', @useself = N'False', @rmtuser = N'admin', @rmtpassword = N''
  1. @rmtuser: It should be admin. Actually, there is no any admin in Windows logins on the system at the same time.
  2. @rmtpassword: It should be an empty string.

Providing access to the linked server via ad hoc queries

This is the second crucial setting. Setting Ad Hoc Distributed Queries to 1 is not enough. One should set to 0 the DisallowAdhocAccess registry key explicitly for the driver specified to @provider:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL12.DEF_INST\Providers\Microsoft.ACE.OLEDB.16.0]

change html input type by JS?

$(".show-pass").click(function (e) {_x000D_
    var type = $("#signupform-password").attr('type');_x000D_
    switch (type) {_x000D_
        case 'password':_x000D_
            $("#signupform-password").attr('type', 'text');_x000D_
        case 'text':_x000D_
            $("#signupform-password").attr('type', 'password');_x000D_
<script src=""></script>_x000D_
<input type="text" name="password" class="show-pass">