Programs & Examples On #X87

x87 is the legacy 80bit floating point subset of the x86 instruction set. It's obsoleted by SSE/SSE2 for float/double, but is still useful for 80bit extended precision. The 32bit x86 ABI also returns FP results in an x87 register. See the tag wiki for a tutorial link. SSL handshake aborted: Failure in SSL library, usually a protocol error

I have got this error report problem, too. My code is under below.

public static void getShop() throws Exception {
    new Thread(new Runnable() {
        public void run() {
            try {
                OkHttpClient client = new OkHttpClient();
                Request request = new Request.Builder()
                Response response = client.newCall(request).execute();
                Log.d("response", response.body().string());
            } catch (Exception e) {

I have my Springboot as my backend and use Android OKHttp to get information. The critical mistake i made was that i use a .url("") in code of Android. But the my backend is not allowed https request. After i use .url(""), then my code went well. So, i want to say my mistake is not the version of emulator, it about the request protocol. I meet another problem after doing what i said, but it's another problem, and i attach the resolve method of the new problem .
Good Luck!GUY!

Sublime Text 2 multiple line edit

I'm not sure it's possible "out of the box". And, unfortunately, I don't know an appropriate plugin either. To solve the problem you suggested you could use regular expressions.

  1. Cmd + F (Find)
  2. Regexp: [^ ]+ (or \d+, or whatever you prefer)
  3. Option + F (Find All)
  4. Edit it

Hotkeys may vary depending on you OS and personal preferences (mine are for OS X).

Python 3 - Encode/Decode vs Bytes/Str

To add to Lennart Regebro's answer There is even the third way that can be used:

encoded3 = str.encode(original, 'utf-8')

Anyway, it is actually exactly the same as the first approach. It may also look that the second way is a syntactic sugar for the third approach.

A programming language is a means to express abstract ideas formally, to be executed by the machine. A programming language is considered good if it contains constructs that one needs. Python is a hybrid language -- i.e. more natural and more versatile than pure OO or pure procedural languages. Sometimes functions are more appropriate than the object methods, sometimes the reverse is true. It depends on mental picture of the solved problem.

Anyway, the feature mentioned in the question is probably a by-product of the language implementation/design. In my opinion, this is a nice example that show the alternative thinking about technically the same thing.

In other words, calling an object method means thinking in terms "let the object gives me the wanted result". Calling a function as the alternative means "let the outer code processes the passed argument and extracts the wanted value".

The first approach emphasizes the ability of the object to do the task on its own, the second approach emphasizes the ability of an separate algoritm to extract the data. Sometimes, the separate code may be that much special that it is not wise to add it as a general method to the class of the object.

Unable instantiate android.gms.maps.MapFragment

Just try to replace your layout with :

<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android=""
       android:layout_height="match_parent" />

You need to use the SupportMapFragment for API under 11 !


How do I initialize a byte array in Java?

private static final int[] CDRIVES = new int[] {0xe0, 0xf4, ...};

and after access convert to byte.

Python: Maximum recursion depth exceeded

You can increment the stack depth allowed - with this, deeper recursive calls will be possible, like this:

import sys
sys.setrecursionlimit(10000) # 10000 is an example, try with different values

... But I'd advise you to first try to optimize your code, for instance, using iteration instead of recursion.

MySQL "incorrect string value" error when save unicode string in Django

If you have this problem here's a python script to change all the columns of your mysql database automatically.

#! /usr/bin/env python
import MySQLdb

host = "localhost"
passwd = "passwd"
user = "youruser"
dbname = "yourdbname"

db = MySQLdb.connect(host=host, user=user, passwd=passwd, db=dbname)
cursor = db.cursor()

cursor.execute("ALTER DATABASE `%s` CHARACTER SET 'utf8' COLLATE 'utf8_unicode_ci'" % dbname)

sql = "SELECT DISTINCT(table_name) FROM information_schema.columns WHERE table_schema = '%s'" % dbname

results = cursor.fetchall()
for row in results:
  sql = "ALTER TABLE `%s` convert to character set DEFAULT COLLATE DEFAULT" % (row[0])

Word wrapping in phpstorm

For Word Wrapping in Php Storm 2019.1.3 Just follow below steps:

from top nagivation menu

View -> Active Editor -> Soft-Wrap

that's it so simple.

How to convert latitude or longitude to meters?

Given you're looking for a simple formula, this is probably the simplest way to do it, assuming that the Earth is a sphere with a circumference of 40075 km.

Length in meters of 1° of latitude = always 111.32 km

Length in meters of 1° of longitude = 40075 km * cos( latitude ) / 360

How can I add a hint text to WPF textbox?

You have to create a custom control by inheriting the textbox. Below link has an excellent example about the search textbox sample. Please have a look at this

Lombok is not generating getter and setter

When starting with a fresh eclipse installation you, in fact, need to "install" Lombok before being able to use it.

  1. Go where you Lombok jar is (e.g. (e.g. you can find in ~/.m2/repository/org/projectlombok/lombok/1.16.10/lombok-1.16.10.jar), run it (Example: java -jar lombok-1.16.10.jar). A window should appear, browse to your eclipse.exe location.
  2. Click on install.
  3. Launch Eclipse, update project configuration on all projects and voila.

Use nginx to serve static files from subdirectories of a given directory

It should work, however says:

When location matches the last part of the directive’s value: it is better to use the root directive instead:

which would yield:

server {
  listen        8080;
  error_log     /home/www-data/logs/nginx_www.error.log;
  error_page    404    /404.html;

  location /public/doc/ {
    autoindex on;
    root  /home/www-data/mysite;

  location = /404.html {
    root /home/www-data/mysite/static/html;

Convert JS date time to MySQL datetime

JS time value for MySQL

var datetime = new Date().toLocaleString();


const DATE_FORMATER = require( 'dateformat' );
var datetime = DATE_FORMATER( new Date(), "yyyy-mm-dd HH:MM:ss" );


const MOMENT= require( 'moment' );
let datetime = MOMENT().format( 'YYYY-MM-DD  HH:mm:ss.000' );

you can send this in params its will work.

How to get start and end of previous month in VB

Try this to get the month in number form:

Month(DateAdd("m", -3, Now))

It will give you 12 for December.

So in your case you would use Month(DateAdd("m", -1, Now)) to just subract one month.

Onclick javascript to make browser go back to previous page?

Shortest Yet!

<button onclick="history.go(-1);">Go back</button>

I prefer the .go(-number) method as then, for 1 or many 'backs' there's only 1 method to use/remember/update/search for, etc.

Also, using a tag for a back button seems more appropriate than tags with names and types...

Run a vbscript from another vbscript

As Martin's Answer didn't work at all for me ("File not found") and atesio's Answer does not allow to call two scripts which include repeating variable definitions, here is another alternative which finally worked for me:

filepath =  Chr(34) & "C:\...\helloworld.vbs" & Chr(34)
Set objshell= CreateObject("WScript.Shell") 
objshell.Run "wscript " & filepath, , True
Set objshell= Nothing

(Windows 8.1)

How can foreign key constraints be temporarily disabled using T-SQL?

Find the constraint

FROM sys.foreign_keys
WHERE referenced_object_id = object_id('TABLE_NAME')

Execute the SQL generated by this SQL

    'ALTER TABLE ' +  OBJECT_SCHEMA_NAME(parent_object_id) +
    '.[' + OBJECT_NAME(parent_object_id) + 
    '] DROP CONSTRAINT ' + name
FROM sys.foreign_keys
WHERE referenced_object_id = object_id('TABLE_NAME')


Note: Added solution for droping the constraint so that table can be dropped or modified without any constraint error.

Ignore 'Security Warning' running script from command line

Did you download the script from internet?

Then remove NTFS stream from the file using sysinternal's streams.exe on command line.

cmd> streams.exe .\my.ps1

Now try to run the script again.

How to put a new line into a wpf TextBlock control?

Insert a "line break" or a "paragraph break" in a RichTextBox "rtb" like this:

var range = new TextRange(rtb.SelectionStart, rtb.Selection.End); 

The only way to get the NewLine items is by inserting text with "\r\n" items first, and then applying more code which works on Selection and/or TextRange objects. This makes sure that the \par items are converted to \line items, are saved as desired, and are still correct when reopening the *.Rtf file. That is what I found so far after hard tries. My three code lines need to be surrounded by more code (with loops) to set the TextPointer items (.Start .End .ContentStart .ContentEnd) where the Lines and Breaks should go, which I have done with success for my purposes.

How can I implement custom Action Bar with custom buttons in Android?

enter image description here

This is pretty much as close as you'll get if you want to use the ActionBar APIs. I'm not sure you can place a colorstrip above the ActionBar without doing some weird Window hacking, it's not worth the trouble. As far as changing the MenuItems goes, you can make those tighter via a style. It would be something like this, but I haven't tested it.

<style name="MyTheme" parent="android:Theme.Holo.Light">
    <item name="actionButtonStyle">@style/MyActionButtonStyle</item>

<style name="MyActionButtonStyle" parent="Widget.ActionButton">
    <item name="android:minWidth">28dip</item>

Here's how to inflate and add the custom layout to your ActionBar.

    // Inflate your custom layout
    final ViewGroup actionBarLayout = (ViewGroup) getLayoutInflater().inflate(

    // Set up your ActionBar
    final ActionBar actionBar = getActionBar();

    // You customization
    final int actionBarColor = getResources().getColor(R.color.action_bar);
    actionBar.setBackgroundDrawable(new ColorDrawable(actionBarColor));

    final Button actionBarTitle = (Button) findViewById(;

    final Button actionBarSent = (Button) findViewById(;

    final Button actionBarStaff = (Button) findViewById(;

    final Button actionBarLocations = (Button) findViewById(;
    actionBarLocations.setText("HIPPA Locations");

Here's the custom layout:

<LinearLayout xmlns:android=""
    android:paddingEnd="8dip" >

        style="@style/ActionBarButtonWhite" />

        style="@style/ActionBarButtonOffWhite" />

        style="@style/ActionBarButtonOffWhite" />

        style="@style/ActionBarButtonOffWhite" />


Here's the color strip layout: To use it, just use merge in whatever layout you inflate in setContentView.

<FrameLayout xmlns:android=""
    android:background="@android:color/holo_blue_dark" />

Here are the Button styles:

<style name="ActionBarButton">
    <item name="android:layout_width">wrap_content</item>
    <item name="android:layout_height">wrap_content</item>
    <item name="android:background">@null</item>
    <item name="android:ellipsize">end</item>
    <item name="android:singleLine">true</item>
    <item name="android:textSize">@dimen/text_size_small</item>

<style name="ActionBarButtonWhite" parent="@style/ActionBarButton">
    <item name="android:textColor">@color/white</item>

<style name="ActionBarButtonOffWhite" parent="@style/ActionBarButton">
    <item name="android:textColor">@color/off_white</item>

Here are the colors and dimensions I used:

<color name="action_bar">#ff0d0d0d</color>
<color name="white">#ffffffff</color>
<color name="off_white">#99ffffff</color>

<!-- Text sizes -->
<dimen name="text_size_small">14.0sp</dimen>
<dimen name="text_size_medium">16.0sp</dimen>

<!-- ActionBar color strip -->
<dimen name="colorstrip">5dp</dimen>

If you want to customize it more than this, you may consider not using the ActionBar at all, but I wouldn't recommend that. You may also consider reading through the Android Design Guidelines to get a better idea on how to design your ActionBar.

If you choose to forgo the ActionBar and use your own layout instead, you should be sure to add action-able Toasts when users long press your "MenuItems". This can be easily achieved using this Gist.

bootstrap datepicker today as default

According to this link Set default date of jquery datepicker, the other solution is

var d = new Date();

var currDate = d.getDate();
var currMonth = d.getMonth();
var currYear = d.getFullYear();

var dateStr = currDate + "-" + currMonth + "-" + currYear;

$("#datepicker").datepicker(({dateFormat: "dd-mm-yy" autoclose: true, defaultDate: dateStr });

Count Vowels in String Python

from collections import Counter

count = Counter()
inputString = str(input("Please type a sentence: "))

for i in inputString:
    if i in "aeiouAEIOU":

Get query string parameters url values with jQuery / Javascript (querystring)

JQuery jQuery-URL-Parser plugin do the same job, for example to retrieve the value of search query string param, you can use


This library is not actively maintained. As suggested by the author of the same plugin, you can use URI.js.

Or you can use js-url instead. Its quite similar to the one below.

So you can access the query param like $.url('?search')

OpenCV - DLL missing, but it's not?

Copy all .dll from /bin in System32

How to get correlation of two vectors in python

The docs indicate that numpy.correlate is not what you are looking for:

numpy.correlate(a, v, mode='valid', old_behavior=False)[source]
  Cross-correlation of two 1-dimensional sequences.
  This function computes the correlation as generally defined in signal processing texts:
     z[k] = sum_n a[n] * conj(v[n+k])
  with a and v sequences being zero-padded where necessary and conj being the conjugate.

Instead, as the other comments suggested, you are looking for a Pearson correlation coefficient. To do this with scipy try:

from scipy.stats.stats import pearsonr   
a = [1,4,6]
b = [1,2,3]   
print pearsonr(a,b)

This gives

(0.99339926779878274, 0.073186395040328034)

You can also use numpy.corrcoef:

import numpy
print numpy.corrcoef(a,b)

This gives:

[[ 1.          0.99339927]
 [ 0.99339927  1.        ]]

position: fixed doesn't work on iPad and iPhone

Avoid on the same box using transform:--- and position:fixed. Element will stay in position:static if there is any transform.

Use jquery click to handle anchor onClick()

Lets take an anchor tag with an onclick event, that calls a Javascript function.

<a href="#" onClick="showDiv(1);">1</a>

Now in javascript write the below code

function showDiv(pageid)

This will show you an alert of "1"....

rake assets:precompile RAILS_ENV=production not working as required

Have you added this gem to your gemfile?

# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'

move that gem out of assets group and then run bundle again, I hope that would help!

How to update single value inside specific array item in redux

I'm afraid that using map() method of an array may be expensive since entire array is to be iterated. Instead, I combine a new array that consists of three parts:

  • head - items before the modified item
  • the modified item
  • tail - items after the modified item

Here the example I've used in my code (NgRx, yet the machanism is the same for other Redux implementations):

// toggle done property: true to false, or false to true

function (state, action) {
    const todos = state.todos;
    const todoIdx = todos.findIndex(t => ===;

    const todoObj = todos[todoIdx];
    const newTodoObj = { ...todoObj, done: !todoObj.done };

    const head = todos.slice(0, todoIdx - 1);
    const tail = todos.slice(todoIdx + 1);
    const newTodos = [...head, newTodoObj, ...tail];

C++ Object Instantiation

Well, the reason to use the pointer would be exactly the same that the reason to use pointers in C allocated with malloc: if you want your object to live longer than your variable!

It is even highly recommended to NOT use the new operator if you can avoid it. Especially if you use exceptions. In general it is much safer to let the compiler free your objects.

The difference between sys.stdout.write and print?

In Python 2, if you need to pass around a function, then you can assign os.sys.stdout.write to a variable. You cannot do this (in the REPL) with print.

>import os
>>> cmd=os.sys.stdout.write
>>> cmd('hello')

That works as expected.

>>> cmd=print
  File "<stdin>", line 1
SyntaxError: invalid syntax

That does not work. print is a magical function.

How to define the css :hover state in a jQuery selector?

Well, you can't add styling using pseudo selectors like :hover, :after, :nth-child, or anything like that using jQuery.

If you want to add a CSS rule like that you have to create a <style> element and add that :hover rule to it just like you would in CSS. Then you would have to add that <style> element to the page.

Using the .hover function seems to be more appropriate if you can't just add the css to a stylesheet, but if you insist you can do:

$('head').append('<style>.myclass:hover div {background-color : red;}</style>')

If you want to read more on adding CSS with javascript you can check out one of David Walsh's Blog posts.

How to get HTML 5 input type="date" working in Firefox and/or IE 10

You can try webshims, which is available on cdn + only loads the polyfill, if it is needed.

Here is a demo with CDN:

<!-- cdn for modernizr, if you haven't included it already -->
<script src=""></script>
<!-- polyfiller file to detect and load polyfills -->
<script src=""></script>
  webshims.setOptions('waitReady', false);
  webshims.setOptions('forms-ext', {types: 'date'});
  webshims.polyfill('forms forms-ext');

<input type="date" />

In case the default configuration does not satisfy, there are many ways to configure it. Here you find the datepicker configurator.

Note: While there might be new bugfix releases for webshim in the future. There won't be any major releases anymore. This includes support for jQuery 3.0 or any new features.

Formula px to dp, dp to px android

px = dp * (dpi / 160)

dp = px * (160 / dpi)

How to convert/parse from String to char in java?

class ss1 
    public static void main(String args[]) 
        String a = new String("sample");
        System.out.println("Result: ");
        for(int i=0;i<a.length();i++)

How to capture no file for fs.readFileSync()?

Try using Async instead to avoid blocking the only thread you have with NodeJS. Check this example:

const util = require('util');
const fs = require('fs');
const path = require('path');
const readFileAsync = util.promisify(fs.readFile);

const readContentFile = async (filePath) => {
  // Eureka, you are using good code practices here!
  const content = await readFileAsync(path.join(__dirname, filePath), {
    encoding: 'utf8'
  return content;

Later can use this async function with try/catch from any other function:

const anyOtherFun = async () => {
  try {
    const fileContent = await readContentFile('my-file.txt');
  } catch (err) {
    // Here you get the error when the file was not found,
    // but you also get any other error

Happy Coding!

How to Create an excel dropdown list that displays text with a numeric hidden value

Data validation drop down

There is a list option in Data validation. If this is combined with a VLOOKUP formula you would be able to convert the selected value into a number.

The steps in Excel 2010 are:

  • Create your list with matching values.
  • On the Data tab choose Data Validation
  • The Data validation form will be displayed
  • Set the Allow dropdown to List
  • Set the Source range to the first part of your list
  • Click on OK (User messages can be added if required)

In a cell enter a formula like this


which will return the matching value from the second part of your list.

Screenshot of Data validation list

Form control drop down

Alternatively, Form controls can be placed on a worksheet. They can be linked to a range and return the position number of the selected value to a specific cell.

The steps in Excel 2010 are:

  • Create your list of data in a worksheet
  • Click on the Developer tab and dropdown on the Insert option
  • In the Form section choose Combo box or List box
  • Use the mouse to draw the box on the worksheet
  • Right click on the box and select Format control
  • The Format control form will be displayed
  • Click on the Control tab
  • Set the Input range to your list of data
  • Set the Cell link range to the cell where you want the number of the selected item to appear
  • Click on OK

Screenshot of form control

Trouble using ROW_NUMBER() OVER (PARTITION BY ...)

It looks like a common gaps-and-islands problem. The difference between two sequences of row numbers rn1 and rn2 give the "group" number.

Run this query CTE-by-CTE and examine intermediate results to see how it works.

Sample data

I expanded sample data from the question a little.

    EmployeeID int,
    DateStarted date,
    DepartmentID int



Query for SQL Server 2008

There is no LEAD function in SQL Server 2008, so I had to use self-join via OUTER APPLY to get the value of the "next" row for the DateEnd.

        ,ROW_NUMBER() OVER (PARTITION BY EmployeeID ORDER BY DateStarted) AS rn1
        ,ROW_NUMBER() OVER (PARTITION BY EmployeeID, DepartmentID ORDER BY DateStarted) AS rn2
    FROM @Source
        ,MIN(DateStarted) AS DateStart
        ,rn1 - rn2
        SELECT TOP(1) G2.DateStart AS DateEnd
        FROM CTE_Groups AS G2
            G2.EmployeeID = CTE_Groups.EmployeeID
            AND G2.DateStart > CTE_Groups.DateStart
        ORDER BY G2.DateStart
    ) AS A

Query for SQL Server 2012+

Starting with SQL Server 2012 there is a LEAD function that makes this task more efficient.

        ,ROW_NUMBER() OVER (PARTITION BY EmployeeID ORDER BY DateStarted) AS rn1
        ,ROW_NUMBER() OVER (PARTITION BY EmployeeID, DepartmentID ORDER BY DateStarted) AS rn2
    FROM @Source
        ,MIN(DateStarted) AS DateStart
        ,rn1 - rn2
    ,LEAD(CTE_Groups.DateStart) OVER (PARTITION BY CTE_Groups.EmployeeID ORDER BY CTE_Groups.DateStart) AS DateEnd


| EmployeeID | DepartmentID | DateStart  |  DateEnd   |
|      10001 |            1 | 2013-01-01 | 2013-12-01 |
|      10001 |            2 | 2013-12-01 | 2014-10-01 |
|      10001 |            1 | 2014-10-01 | NULL       |
|      10005 |            1 | 2013-05-01 | 2013-12-01 |
|      10005 |            2 | 2013-12-01 | 2014-10-01 |
|      10005 |            1 | 2014-10-01 | NULL       |

How to change the background color on a Java panel?

setBackground() is the right method to use. Did you repaint after you changed it? If you change it before you make the panel (or its containing frame) visible it should work

How to increase font size in the Xcode editor?

You can use this plugin to change the font size using ? + or ? - (Control - and Control + in the latest versions of Xcode. The plugin developers changed the shortcut to avoid conflict with Interface Builder hotkeys):

How to create a date object from string in javascript

The syntax is as follows:

new Date(year, month [, day, hour, minute, second, millisecond ])


Date d = new Date(2011,10,30);

is correct; day, hour, minute, second, millisecond are optional.

How to round the minute of a datetime object

I used Stijn Nevens code (thank you Stijn) and have a little add-on to share. Rounding up, down and rounding to nearest.

update 2019-03-09 = comment Spinxz incorporated; thank you.

update 2019-12-27 = comment Bart incorporated; thank you.

Tested for date_delta of "X hours" or "X minutes" or "X seconds".

import datetime

def round_time(dt=None, date_delta=datetime.timedelta(minutes=1), to='average'):
    Round a datetime object to a multiple of a timedelta
    dt : datetime.datetime object, default now.
    dateDelta : timedelta object, we round to a multiple of this, default 1 minute.
    round_to = date_delta.total_seconds()
    if dt is None:
        dt =
    seconds = (dt - dt.min).seconds

    if seconds % round_to == 0 and dt.microsecond == 0:
        rounding = (seconds + round_to / 2) // round_to * round_to
        if to == 'up':
            # // is a floor division, not a comment on following line (like in javascript):
            rounding = (seconds + dt.microsecond/1000000 + round_to) // round_to * round_to
        elif to == 'down':
            rounding = seconds // round_to * round_to
            rounding = (seconds + round_to / 2) // round_to * round_to

    return dt + datetime.timedelta(0, rounding - seconds, - dt.microsecond)

# test data
print(round_time(datetime.datetime(2019,11,1,14,39,00), date_delta=datetime.timedelta(seconds=30), to='up'))
print(round_time(datetime.datetime(2019,11,2,14,39,00,1), date_delta=datetime.timedelta(seconds=30), to='up'))
print(round_time(datetime.datetime(2019,11,3,14,39,00,776980), date_delta=datetime.timedelta(seconds=30), to='up'))
print(round_time(datetime.datetime(2019,11,4,14,39,29,776980), date_delta=datetime.timedelta(seconds=30), to='up'))
print(round_time(datetime.datetime(2018,11,5,14,39,00,776980), date_delta=datetime.timedelta(seconds=30), to='down'))
print(round_time(datetime.datetime(2018,11,6,14,38,59,776980), date_delta=datetime.timedelta(seconds=30), to='down'))
print(round_time(datetime.datetime(2017,11,7,14,39,15), date_delta=datetime.timedelta(seconds=30), to='average'))
print(round_time(datetime.datetime(2017,11,8,14,39,14,999999), date_delta=datetime.timedelta(seconds=30), to='average'))
print(round_time(datetime.datetime(2019,11,9,14,39,14,999999), date_delta=datetime.timedelta(seconds=30), to='up'))

Formula to convert date to number

The Excel number for a modern date is most easily calculated as the number of days since 12/30/1899 on the Gregorian calendar.

Excel treats the mythical date 01/00/1900 (i.e., 12/31/1899) as corresponding to 0, and incorrectly treats year 1900 as a leap year. So for dates before 03/01/1900, the Excel number is effectively the number of days after 12/31/1899.

However, Excel will not format any number below 0 (-1 gives you ##########) and so this only matters for "01/00/1900" to 02/28/1900, making it easier to just use the 12/30/1899 date as a base.

A complete function in DB2 SQL that accounts for the leap year 1900 error:

   - DAYS(DATE('1899-12-30'))
   - CASE                       
        WHEN INPUT_DATE < DATE('1900-03-01')  
           THEN 1               
           ELSE 0               

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

function CurFocus()

function pageLoad()

window.onload = pageLoad;

Changing the child element's CSS when the parent is hovered

If you're using Twitter Bootstrap styling and base JS for a drop down menu:

.child{ display:none; }
.parent:hover .child{ display:block; }

This is the missing piece to create sticky-dropdowns (that aren't annoying)

  • The behavior is to:
    1. Stay open when clicked, close when clicking again anywhere else on the page
    2. Close automatically when the mouse scrolls out of the menu's elements.

How to check a string starts with numeric number?

Sorry I didn't see your Java tag, was reading question only. I'll leave my other answers here anyway since I've typed them out.


String myString = "9Hello World!";
if ( Character.isDigit(myString.charAt(0)) )
    System.out.println("String begins with a digit");


string myString = "2Hello World!";

if (isdigit( myString[0]) )
    printf("String begins with a digit");

Regular expression:


Some proof my regex works: Unless my test data is wrong? alt text

How to set background color of view transparent in React Native

Surprisingly no one told about this, which provides some !clarity:

backgroundColor: 'white',
opacity: 0.7

Using Python's os.path, how do I go up one directory?

Go up a level from the work directory

import os

or from the current directory

import os
os.path.dirname('current path')

How to store NULL values in datetime fields in MySQL?

This is a a sensible point.

A null date is not a zero date. They may look the same, but they ain't. In mysql, a null date value is null. A zero date value is an empty string ('') and '0000-00-00 00:00:00'

On a null date "... where mydate = ''" will fail.
On an empty/zero date "... where mydate is null" will fail.

But now let's get funky. In mysql dates, empty/zero date are strictly the same.

by example

select if(myDate is null, 'null', myDate) as mydate from myTable where  myDate = '';
select if(myDate is null, 'null', myDate) as mydate from myTable where  myDate = '0000-00-00 00:00:00'

will BOTH output: '0000-00-00 00:00:00'. if you update myDate with '' or '0000-00-00 00:00:00', both selects will still work the same.

In php, the mysql null dates type will be respected with the standard mysql connector, and be real nulls ($var === null, is_null($var)). Empty dates will always be represented as '0000-00-00 00:00:00'.

I strongly advise to use only null dates, OR only empty dates if you can. (some systems will use "virual" zero dates which are valid Gregorian dates, like 1970-01-01 (linux) or 0001-01-01 (oracle).

empty dates are easier in php/mysql. You don't have the "where field is null" to handle. However, you have to "manually" transform the '0000-00-00 00:00:00' date in '' to display empty fields. (to store or search you don't have special case to handle for zero dates, which is nice).

Null dates need better care. you have to be careful when you insert or update to NOT add quotes around null, else a zero date will be inserted instead of null, which causes your standard data havoc. In search forms, you will need to handle cases like "and mydate is not null", and so on.

Null dates are usually more work. but they much MUCH MUCH faster than zero dates for queries.

When using .net MVC RadioButtonFor(), how do you group so only one selection can be made?

The first parameter of Html.RadioButtonFor() should be the property name you're using, and the second parameter should be the value of that specific radio button. Then they'll have the same name attribute value and the helper will select the given radio button when/if it matches the property value.


<div class="editor-field">
    <%= Html.RadioButtonFor(m => m.Gender, "M" ) %> Male
    <%= Html.RadioButtonFor(m => m.Gender, "F" ) %> Female

Here's a more specific example:

I made a quick MVC project named "DeleteMeQuestion" (DeleteMe prefix so I know that I can remove it later after I forget about it).

I made the following model:

namespace DeleteMeQuestion.Models
    public class QuizModel
        public int ParentQuestionId { get; set; }
        public int QuestionId { get; set; }
        public string QuestionDisplayText { get; set; }
        public List<Response> Responses { get; set; }

        [Range(1,999, ErrorMessage = "Please choose a response.")]
        public int SelectedResponse { get; set; }

    public class Response
        public int ResponseId { get; set; }
        public int ChildQuestionId { get; set; }
        public string ResponseDisplayText { get; set; }

There's a simple range validator in the model, just for fun. Next up, I made the following controller:

namespace DeleteMeQuestion.Controllers
    public class HomeController : Controller
        public ActionResult Index(int? id)
            // TODO: get question to show based on method parameter 
            var model = GetModel(id);
            return View(model);

        public ActionResult Index(int? id, QuizModel model)
            if (!ModelState.IsValid)
                var freshModel = GetModel(id);
                return View(freshModel);

            // TODO: save selected answer in database
            // TODO: get next question based on selected answer (hard coded to 999 for now)

            var nextQuestionId = 999;
            return RedirectToAction("Index", "Home", new {id = nextQuestionId});

        private QuizModel GetModel(int? questionId)
            // just a stub, in lieu of a database

            var model = new QuizModel
                QuestionDisplayText = questionId.HasValue ? "And so on..." : "What is your favorite color?",
                QuestionId = 1,
                Responses = new List<Response>
                                                    new Response
                                                            ChildQuestionId = 2,
                                                            ResponseId = 1,
                                                            ResponseDisplayText = "Red"
                                                    new Response
                                                            ChildQuestionId = 3,
                                                            ResponseId = 2,
                                                            ResponseDisplayText = "Blue"
                                                    new Response
                                                            ChildQuestionId = 4,
                                                            ResponseId = 3,
                                                            ResponseDisplayText = "Green"

            return model;

Finally, I made the following view that makes use of the model:

<%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<DeleteMeQuestion.Models.QuizModel>" %>

<asp:Content ContentPlaceHolderID="TitleContent" runat="server">
    Home Page

<asp:Content ContentPlaceHolderID="MainContent" runat="server">

    <% using (Html.BeginForm()) { %>


            <h1><%: Model.QuestionDisplayText %></h1>

            <% foreach (var item in Model.Responses) { %>
                    <%= Html.RadioButtonFor(m => m.SelectedResponse, item.ResponseId, new {id="Response" + item.ResponseId}) %>
                    <label for="Response<%: item.ResponseId %>"><%: item.ResponseDisplayText %></label>
            <% } %>

            <%= Html.ValidationMessageFor(m => m.SelectedResponse) %>


        <input type="submit" value="Submit" />

    <% } %>


As I understand your context, you have questions with a list of available answers. Each answer will dictate the next question. Hopefully that makes sense from my model and TODO comments.

This gives you the radio buttons with the same name attribute, but different ID attributes.

R : how to simply repeat a command?

It's not clear whether you're asking this because you are new to programming, but if that's the case then you should probably read this article on loops and indeed read some basic materials on programming.

If you already know about control structures and you want the R-specific implementation details then there are dozens of tutorials around, such as this one. The other answer uses replicate and colMeans, which is idiomatic when writing in R and probably blazing fast as well, which is important if you want 10,000 iterations.

However, one more general and (for beginners) straightforward way to approach problems of this sort would be to use a for loop.

> for (ii in 1:5) { + print(ii) + } [1] 1 [1] 2 [1] 3 [1] 4 [1] 5 > 

So in your case, if you just wanted to print the mean of your Tandem object 5 times:

for (ii in 1:5) {     Tandem <- sample(OUT, size = 815, replace = TRUE, prob = NULL)     TandemMean <- mean(Tandem)     print(TandemMean) } 

As mentioned above, replicate is a more natural way to deal with this specific problem using R. Either way, if you want to store the results - which is surely the case - you'll need to start thinking about data structures like vectors and lists. Once you store something you'll need to be able to access it to use it in future, so a little knowledge is vital.

set.seed(1234) OUT <- runif(100000, 1, 2) tandem <- list() for (ii in 1:10000) {     tandem[[ii]] <- mean(sample(OUT, size = 815, replace = TRUE, prob = NULL)) }  tandem[1] tandem[100] tandem[20:25] 

...creates this output:

> set.seed(1234) > OUT <- runif(100000, 1, 2) > tandem <- list() > for (ii in 1:10000) { +     tandem[[ii]] <- mean(sample(OUT, size = 815, replace = TRUE, prob = NULL)) + } >  > tandem[1] [[1]] [1] 1.511923  > tandem[100] [[1]] [1] 1.496777  > tandem[20:25] [[1]] [1] 1.500669  [[2]] [1] 1.487552  [[3]] [1] 1.503409  [[4]] [1] 1.501362  [[5]] [1] 1.499728  [[6]] [1] 1.492798  >  

Print series of prime numbers in python

A Python Program function module that returns the 1'st N prime numbers:

def get_primes(count):
        Return the 1st count prime integers.
    result = []
    while len(result) in range(count):
        for i in range(2,x):
            if x%i == 0:
        if flag == 0:
    return result

Convert default format to Timestamp in Java

You can use DateFormat(java.text.*) to parse the date:

DateFormat df = new SimpleDateFormat("EEE MMM dd kk:mm:ss z yyyy", Locale.ENGLISH);
Date d = df.parse("Mon May 27 11:46:15 IST 2013")

You will have to change the locale to match your own (with this you will get 10:46:15). Then you can use the same code you have to convert it to a timestamp.

How to click or tap on a TextView text

To click on a piece of the text (not the whole TextView), you can use Html or Linkify (both create links that open urls, though, not a callback in the app).


Use a string resource like:

<string name="links">Here is a link:</string>

Then in a textview:

TextView textView = ...
Linkify.addLinks(textView, Linkify.ALL);


Using Html.fromHtml:

<string name="html">Here you can put html &lt;a href=""&gt;Link!&lt;/&gt;</string>

Then in your textview:


How to send a pdf file directly to the printer using JavaScript?

Try this: Have a button/link which opens a webpage (in a new window) with just the pdf file embedded in it, and print the webpage.

In head of the main page:

<script type="text/javascript">
function printpdf() 
myWindow.close;  //optional, to close the new window as soon as it opens
//this ensures user doesn't have to close the pop-up manually

And in body of the main page:

<a href="printpdf()">Click to Print the PDF</a>

Inside pdfwebpage.html:


<body onload="window.print()">
<embed src="pdfhere.pdf"/>


Why is Dictionary preferred over Hashtable in C#?

Notice that the documentation says: "the Dictionary<(Of <(TKey, TValue>)>) class is implemented as a hash table", not "the Dictionary<(Of <(TKey, TValue>)>) class is implemented as a HashTable"

Dictionary is NOT implemented as a HashTable, but it is implemented following the concept of a hash table. The implementation is unrelated to the HashTable class because of the use of Generics, although internally Microsoft could have used the same code and replaced the symbols of type Object with TKey and TValue.

In .NET 1.0 Generics did not exist; this is where the HashTable and ArrayList originally began.

How can I set / change DNS using the command-prompt at windows 8

Here is another way to change DNS by using WMIC (Windows Management Instrumentation Command-line).

The commands must be run as administrator to apply.

Clear DNS servers:

wmic nicconfig where (IPEnabled=TRUE) call SetDNSServerSearchOrder ()

Set 1 DNS server:

wmic nicconfig where (IPEnabled=TRUE) call SetDNSServerSearchOrder ("")

Set 2 DNS servers:

wmic nicconfig where (IPEnabled=TRUE) call SetDNSServerSearchOrder ("", "")

Set 2 DNS servers on a particular network adapter:

wmic nicconfig where "(IPEnabled=TRUE) and (Description = 'Local Area Connection')" call SetDNSServerSearchOrder ("", "")

Another example for setting the domain search list:

wmic nicconfig call SetDNSSuffixSearchOrder ("domain.tld")

How to import NumPy in the Python shell

On Debian/Ubuntu:

aptitude install python-numpy

On Windows, download the installer:

On other systems, download the tar.gz and run the following:

$ tar xfz numpy-n.m.tar.gz
$ cd numpy-n.m
$ python install

Unprotect workbook without password

Try the below code to unprotect the workbook. It works for me just fine in excel 2010 but I am not sure if it will work in 2013.

Sub PasswordBreaker()
    'Breaks worksheet password protection.
    Dim i As Integer, j As Integer, k As Integer
    Dim l As Integer, m As Integer, n As Integer
    Dim i1 As Integer, i2 As Integer, i3 As Integer
    Dim i4 As Integer, i5 As Integer, i6 As Integer
    On Error Resume Next
    For i = 65 To 66: For j = 65 To 66: For k = 65 To 66
    For l = 65 To 66: For m = 65 To 66: For i1 = 65 To 66
    For i2 = 65 To 66: For i3 = 65 To 66: For i4 = 65 To 66
    For i5 = 65 To 66: For i6 = 65 To 66: For n = 32 To 126
    ThisWorkbook.Unprotect Chr(i) & Chr(j) & Chr(k) & _
        Chr(l) & Chr(m) & Chr(i1) & Chr(i2) & Chr(i3) & _
        Chr(i4) & Chr(i5) & Chr(i6) & Chr(n)
    If ThisWorkbook.ProtectStructure = False Then
        MsgBox "One usable password is " & Chr(i) & Chr(j) & _
            Chr(k) & Chr(l) & Chr(m) & Chr(i1) & Chr(i2) & _
            Chr(i3) & Chr(i4) & Chr(i5) & Chr(i6) & Chr(n)
         Exit Sub
    End If
    Next: Next: Next: Next: Next: Next
    Next: Next: Next: Next: Next: Next
End Sub

How to set null to a GUID property

I think this is the correct way:

Guid filed = Guid.Empty;

Referenced Project gets "lost" at Compile Time

Check your build types of each project under project properties - I bet one or the other will be set to build against .NET XX - Client Profile.

With inconsistent versions, specifically with one being Client Profile and the other not, then it works at design time but fails at compile time. A real gotcha.

There is something funny going on in Visual Studio 2010 for me, which keeps setting projects seemingly randomly to Client Profile, sometimes when I create a project, and sometimes a few days later. Probably some keyboard shortcut I'm accidentally hitting...

Using Javamail to connect to Gmail smtp server ignores specified port and tries to use 25

For anyone looking for a full solution, I got this working with the following code based on maximdim's answer:

import javax.mail.*
import javax.mail.internet.*

private class SMTPAuthenticator extends Authenticator
    public PasswordAuthentication getPasswordAuthentication()
        return new PasswordAuthentication('[email protected]', 'test1234');

def  d_email = "[email protected]",
        d_uname = "email",
        d_password = "password",
        d_host = "",
        d_port  = "465", //465,587
        m_to = "[email protected]",
        m_subject = "Testing",
        m_text = "Hey, this is the testing email."

def props = new Properties()
props.put("mail.smtp.user", d_email)
props.put("", d_host)
props.put("mail.smtp.port", d_port)
props.put("mail.smtp.debug", "true");
props.put("mail.smtp.auth", "true")
props.put("mail.smtp.socketFactory.port", d_port)
props.put("mail.smtp.socketFactory.class", "")
props.put("mail.smtp.socketFactory.fallback", "false")

def auth = new SMTPAuthenticator()
def session = Session.getInstance(props, auth)

def msg = new MimeMessage(session)
msg.setFrom(new InternetAddress(d_email))
msg.addRecipient(Message.RecipientType.TO, new InternetAddress(m_to))

Transport transport = session.getTransport("smtps");
transport.connect(d_host, 465, d_uname, d_password);
transport.sendMessage(msg, msg.getAllRecipients());

How to convert a String to a Date using SimpleDateFormat?

You have used some type errors. If you want to set 08/16/2011 to following pattern. It is wrong because,

mm stands for minutes, use MM as it is for Months

DD is wrong, it should be dd which represents Days

Try this to achieve the output you want to get ( Tue Aug 16 "Whatever Time" IST 2011 ),

    String date = "08/16/2011"; //input date as String

    SimpleDateFormat simpleDateFormat = new SimpleDateFormat("MM/dd/yyyy"); // date pattern

    Date myDate = simpleDateFormat.parse(date); // returns date object 

    System.out.println(myDate); //outputs: Tue Aug 16 00:00:00 IST 2011

ImportError: No module named PyQt4.QtCore

I had the same issue when uninstalled my Python27 and re-installed it.

I downloaded the sip-4.15.5 and PyQt-win-gpl-4.10.4 and installed/configured both of them. it still gives 'ImportError: No module named PyQt4.QtCore'. I tried to move the files/folders in Lib to make it looked 'have' but not working.

in fact, jut download the Windows 64 bit installer for a suitable Python version (my case) from and installed it, will do the job.

* March 2017 update *

The given link says, Binary installers for Windows are no longer provided.

See cgohlke's answer at, PyQt4 and 64-bit python.

  1. Download the .whl file at
  2. Use pip to install the downloaded .whl file.

How to call a JavaScript function, declared in <head>, in the body when I want to call it

You can call it like that:

<!DOCTYPE html>
<html lang="en">
        <script type="text/javascript">
            var person = { name: 'Joe Blow' };
            function myfunction() {
        <script type="text/javascript">

The result should be page with the only content: Joe Blow

Look here:

Best regards!

Fatal error: Call to undefined function mysql_connect()

You upgraded to PHP 7, and now mysql_connect is deprecated. Check yours with:

php -version

Change it to mysqli_connect as in:

$host = "";
$username = "root";
$pass = "foobar";
$con = mysqli_connect($host, $username, $pass, "your_database");

If you're upgrading legacy PHP, now you're faced with the task of upgrading all your mysql_* functions with mysqli_* functions.

What are some reasons for jquery .focus() not working?

The problem in my case was that I entered a value IN THE LAST NOT DISABLED ELEMENT of the site and used tab to raise the onChange-Event. After that there is no next element to get the focus, so the "browser"-Focus switches to the browser-functionality (tabs, menu, and so on) and is not any longer inside the html-content.

To understand that, place a displayed, not disabled dummy-textbox at the end of your html-code. In that you can "park" the focus for later replacing. Should work. In my case. All other tries didnt work, also the setTimeout-Version.

Checked this out for about an hour, because it made me insane :)


jquery - fastest way to remove all rows from a very large table

Using detach is magnitudes faster than any of the other answers here:


Don't forget to put the tbody element back into the table since detach removed it:


Also note that when talking efficiency $(target).find(child) syntax is faster than $(target > child). Why? Sizzle!

Elapsed Time to Empty 3,161 Table Rows

Using the Detach() method (as shown in my example above):

  • Firefox: 0.027s
  • Chrome: 0.027s
  • Edge: 1.73s
  • IE11: 4.02s

Using the empty() method:

  • Firefox: 0.055s
  • Chrome: 0.052s
  • Edge: 137.99s (might as well be frozen)
  • IE11: Freezes and never returns

How to recover deleted rows from SQL server table?

I think thats impossible, sorry.

Thats why whenever running a delete or update you should always use BEGIN TRANSACTION, then COMMIT if successful or ROLLBACK if not.

For-loop vs while loop in R

The variable in the for loop is an integer sequence, and so eventually you do this:

> y=as.integer(60000)*as.integer(60000)
Warning message:
In as.integer(60000) * as.integer(60000) : NAs produced by integer overflow

whereas in the while loop you are creating a floating point number.

Its also the reason these things are different:

> seq(0,2,1)
[1] 0 1 2
> seq(0,2)
[1] 0 1 2

Don't believe me?

> identical(seq(0,2),seq(0,2,1))


> is.integer(seq(0,2))
[1] TRUE
> is.integer(seq(0,2,1))

How to save final model using keras?

The model has a save method, which saves all the details necessary to reconstitute the model. An example from the keras documentation:

from keras.models import load_model'my_model.h5')  # creates a HDF5 file 'my_model.h5'
del model  # deletes the existing model

# returns a compiled model
# identical to the previous one
model = load_model('my_model.h5')

Getting the last n elements of a vector. Is there a better way than using the length() function?

How about rev(x)[1:5]?

 user  system elapsed 
 138.85    0.26  139.28 

 user  system elapsed 
 61.97    0.25   62.23

Determine what user created objects in SQL Server

If the object was recently created, you can check the Schema Changes History report, within the SQL Server Management Studio, which "provides a history of all committed DDL statement executions within the Database recorded by the default trace":

enter image description here

You then can search for the create statements of the objects. Among all the information displayed, there is the login name of whom executed the DDL statement.

Print newline in PHP in single quotes

There IS a difference on using single VS double quotes in PHP

e.g: 1. echo '$var\n'; 2. echo "$var\n";

  • in 1, PHP will print literally: $var\n
  • in 2, PHP will have to search the location in memory for $var, and return the value in that location, also, it will have to parse the \n as a new line character and print that result

We're in the range of millionths of a second, but there IS a difference in performance. I would recommend you to use single quotes whenever possible, even knowing you won't be able to perceive this performance increase. But I'm a paranoid developer when it comes to performance.

How to execute a Ruby script in Terminal?

Assuming ruby interpreter is in your PATH (it should be), you simply run

ruby your_file.rb

if, elif, else statement issues in Bash

[ is a command (or a builtin in some shells). It must be separated by whitespace from the preceding statement:

elif [

jQuery .scrollTop(); + animation

for this you can use callback method

    }, 500, 
    function(){} // callback method use this space how you like

sorting a List of Map<String, String>

try {
                new Comparator<Map<String, String>>() {
                    SimpleDateFormat sdf = new SimpleDateFormat(

                    public int compare(final Map<String, String> map1,
                            final Map<String, String> map2) {
                        Date date1 = null, date2 = null;
                        try {
                            date1 = sdf.parse(map1.get("Date"));
                            date2 = sdf.parse(map2.get("Date"));
                        } catch (ParseException e) {
                        if (date1.compareTo(date2) > 0) {
                            return +1;
                        } else if (date1.compareTo(date2) == 0) {
                            return 0;
                        } else {
                            return -1;

    } catch (Exception e) {


Is there an easy way to add a border to the top and bottom of an Android View?

Try wrapping the image with a linearlayout, and set it's background to the border color you want around the text. Then set the padding on the textview to be the thickness you want for your border.

List directory in Go

From your description, what you probably want is os.Readdirnames.

func (f *File) Readdirnames(n int) (names []string, err error)

Readdirnames reads the contents of the directory associated with file and returns a slice of up to n names of files in the directory, in directory order. Subsequent calls on the same file will yield further names.


If n <= 0, Readdirnames returns all the names from the directory in a single slice.


file, err := os.Open(path)
if err != nil {
    return err
defer file.Close()
names, err := file.Readdirnames(0)
if err != nil {
    return err

Credit to SquattingSlavInTracksuit's comment; I'd have suggested promoting their comment to an answer if I could.

How do you launch the JavaScript debugger in Google Chrome?

For Mac users, go to Google Chrome --> menu View --> Developer --> JavaScript Console.


Array as session variable

session_start();          //php part
$student_name=$_POST['student_name']; //student_name form field name
$student_city=$_POST['city_id'];   //city_id form field name

<table class="table">     //html part

     <?php for($i = 0 ; $i < count($_SESSION['student']) ; $i++) {
     echo '<td>'.$_SESSION['student'][$i].'</td>';
     }  ?>

.bashrc: Permission denied

The .bashrc file is in your user home directory (~/.bashrc or ~vagrant/.bashrc both resolve to the same path), inside the VM's filesystem. This file is invisible on the host machine, so you can't use any Windows editors to edit it directly.

You have two simple choices:

  1. Learn how to use a console-based text editor. My favourite is vi (or vim), which takes 15 minutes to learn the basics and is much quicker for simple edits than anything else.

    vi .bashrc

  2. Copy .bashrc out to /vagrant (which is a shared directory) and edit it using your Windows editors. Make sure not to save it back with any extensions.

    cp .bashrc /vagrant ... edit using your host machine ... cp /vagrant/.bashrc .

I'd recommend getting to know the command-line based editors. Once you're working inside the VM, it's best to stay there as otherwise you might just get confused.

You (the vagrant user) are the owner of your home .bashrc so you do have permissions to edit it.

Once edited, you can execute it by typing source .bashrc I prefer to logout and in again (there may be more than one file executed on login).

Get a particular cell value from HTML table using JavaScript

Here is perhaps the simplest way to obtain the value of a single cell.


where r is the row index and c is the column index

Therefore, to obtain all cell data and put it in a multi-dimensional array:

var tableData = [];  
Array.from(document.querySelector("#table").children[0].children).forEach(function(tr){tableData.push(Array.from(tr.children).map(cell => cell.innerText))}); 
var cell = tableData[1][2];//2nd row, 3rd column

To access a specific cell's data in this multi-dimensional array, use the standard syntax: array[rowIndex][columnIndex].

How to clear cache in Yarn?

Also note that the cached directory is located in ~/.yarn-cache/:

yarn cache clean: cleans that directory

yarn cache list: shows the list of cached dependencies

yarn cache dir: prints out the path of your cached directory

Convert DateTime to TimeSpan


Make a number a percentage

A percentage is just:

(number_one / number_two) * 100

No need for anything fancy:

var number1 = 4.954848;
var number2 = 5.9797;

alert(Math.floor((number1 / number2) * 100)); //w00t!

In Rails, how do you render JSON using a view?

As others have mentioned you need a users/show.json view, but there are options to consider for the templating language...


Works out of the box. Great for HTML, but you'll quickly find it's awful for JSON.


Good solution. Have to add a dependency and learn its DSL.

JSON Builder

Same deal as RABL: Good solution. Have to add a dependency and learn its DSL.

Plain Ruby

Ruby is awesome at generating JSON and there's nothing new to learn as you can call to_json on a Hash or an AR object. Simply register the .rb extension for templates (in an initializer):

ActionView::Template.register_template_handler(:rb, :source.to_proc)

Then create the view users/show.json.rb:


For more info on this approach see

Http post and get request in angular 6

Update : In angular 7, they are the same as 6

In angular 6

the complete answer found in live example

  /** POST: add a new hero to the database */
  addHero (hero: Hero): Observable<Hero> {
 return<Hero>(this.heroesUrl, hero, httpOptions)
    catchError(this.handleError('addHero', hero))
  /** GET heroes from the server */
 getHeroes (): Observable<Hero[]> {
return this.http.get<Hero[]>(this.heroesUrl)
    catchError(this.handleError('getHeroes', []))

it's because of pipeable/lettable operators which now angular is able to use tree-shakable and remove unused imports and optimize the app

some rxjs functions are changed

do -> tap
catch -> catchError
switch -> switchAll
finally -> finalize


and Import paths

For JavaScript developers, the general rule is as follows:

rxjs: Creation methods, types, schedulers and utilities

import { Observable, Subject, asapScheduler, pipe, of, from, interval, merge, fromEvent } from 'rxjs';

rxjs/operators: All pipeable operators:

import { map, filter, scan } from 'rxjs/operators';

rxjs/webSocket: The web socket subject implementation

import { webSocket } from 'rxjs/webSocket';

rxjs/ajax: The Rx ajax implementation

import { ajax } from 'rxjs/ajax';

rxjs/testing: The testing utilities

import { TestScheduler } from 'rxjs/testing';

and for backward compatability you can use rxjs-compat

Access key value from Web.config in Razor View-MVC3 ASP.NET


-- WEB.CONFIG CODE IN APP SETTING -- <add key="PhaseLevel" value="1" />

-- ON VIEWS suppose you want to show or hide something based on web.config Value--

-- WRITE THIS ON TOP OF YOUR PAGE-- @{ var phase = System.Configuration.ConfigurationManager.AppSettings["PhaseLevel"].ToString(); }


@if (phase != "1") { @Html.Partial("~/Views/Shared/_LeftSideBarPartial.cshtml") }

Kotlin - How to correctly concatenate a String

Similar to @Rhusfer answer I wrote this. In case you have a group of EditTexts and want to concatenate their values, you can write:

listOf(edit_1, edit_2, edit_3, edit_4).joinToString(separator = "") { it.text.toString() }

If you want to concatenate Map, use this:

map.entries.joinToString(separator = ", ")

To concatenate Bundle, use

bundle.keySet().joinToString(", ") { key -> "$key=${bundle[key]}" }

It sorts keys in alphabetical order.


val map: MutableMap<String, Any> = mutableMapOf("price" to 20.5)
map += "arrange" to 0
map += "title" to "Night cream"
println(map.entries.joinToString(separator = ", "))

// price=20.5, arrange=0, title=Night cream

val bundle = bundleOf("price" to 20.5)
bundle.putAll(bundleOf("arrange" to 0))
bundle.putAll(bundleOf("title" to "Night cream"))
val bundleString =
    bundle.keySet().joinToString(", ") { key -> "$key=${bundle[key]}" }

// arrange=0, price=20.5, title=Night cream

Check if a class is derived from a generic class

Try this code

static bool IsSubclassOfRawGeneric(Type generic, Type toCheck) {
    while (toCheck != null && toCheck != typeof(object)) {
        var cur = toCheck.IsGenericType ? toCheck.GetGenericTypeDefinition() : toCheck;
        if (generic == cur) {
            return true;
        toCheck = toCheck.BaseType;
    return false;

Build a simple HTTP server in C

I'd recommend that you take a look at: A Practical Guide to Writing Clients and Servers

What you have to implement in incremental steps is:

  1. Get your basic TCP sockets layer running (listen on port/ports, accept client connections and send/receive data).
  2. Implement a buffered reader so that you can read requests one line (delimited by CRLF) at a time.
  3. Read the very first line. Parse out the method, the request version and the path.
  4. Implement header parsing for the "Header: value" syntax. Don't forget unfolding folded headers.
  5. Check the request method, content type and content size to determine how/if the body will be read.
  6. Implement decoding of content based on content type.
  7. If you're going to support HTTP 1.1, implement things like "100 Continue", keep-alive, chunked transfer.
  8. Add robustness/security measures like detecting incomplete requests, limiting max number of clients etc.
  9. Shrink wrap your code and open-source it :)

Extract the filename from a path

Use :

[System.IO.Path]::GetFileName("c:\foo.txt") returns foo.txt. [System.IO.Path]::GetFileNameWithoutExtension("c:\foo.txt") returns foo

C++ "was not declared in this scope" compile error

fix function declaration on

int nonrecursivecountcells(color grid[ROW_SIZE][COL_SIZE], int row, int column) vs location.hostname and cross-browser compatibility?

Your primary question has been answered above. I just wanted to point out that the regex you're using has a bug. It will also succeed on which is not a subdomain of

What you really want is this:


Switch statement with returns -- code correctness

If you have "lookup" type of code, you could package the switch-case clause in a method by itself.

I have a few of these in a "hobby" system I'm developing for fun:

private int basePerCapitaIncomeRaw(int tl) {
    switch (tl) {
        case 0:     return 7500;
        case 1:     return 7800;
        case 2:     return 8100;
        case 3:     return 8400;
        case 4:     return 9600;
        case 5:     return 13000;
        case 6:     return 19000;
        case 7:     return 25000;
        case 8:     return 31000;
        case 9:     return 43000;
        case 10:    return 67000;
        case 11:    return 97000;
        default:    return 130000;

(Yep. That's GURPS space...)

I agree with others that you should in most cases avoid more than one return in a method, and I do recognize that this one might have been better implemented as an array or something else. I just found switch-case-return to be a pretty easy match to a lookup table with a 1-1 correlation between input and output, like the above thing (role-playing games are full of them, I am sure they exist in other "businesses" as well) :D

On the other hand, if the case-clause is more complex, or something happens after the switch-statement, I wouldn't recommend using return in it, but rather set a variable in the switch, end it with a break, and return the value of the variable in the end.

(On the ... third? hand... you can always refactor a switch into its own method... I doubt it will have an effect on performance, and it wouldn't surprise me if modern compilers could even recognize it as something that could be inlined...)

overlay two images in android to set an imageview

ok just so you know there is a program out there that's called DroidDraw. It can help you draw objects and try them one on top of the other. I tried your solution but I had animation under the smaller image so that didn't work. But then I tried to place one image in a relative layout that's suppose to be under first and then on top of that I drew the other image that is suppose to overlay and everything worked great. So RelativeLayout, DroidDraw and you are good to go :) Simple, no any kind of jiggery pockery :) and here is a bit of code for ya:

The logo is going to be on top of shazam background image.

<?xml version="1.0" encoding="utf-8"?>
</RelativeLayout> localhost/ - Connection refused

in android

Replace: String webServiceUrl = "http://localhost:8080/Service1.asmx"

With : String webServiceUrl = ""

Good luck!

How can I call controller/view helper methods from the console in Ruby on Rails?

Inside any controller action or view, you can invoke the console by calling the console method.

For example, in a controller:

class PostsController < ApplicationController
  def new
    @post =

Or in a view:

<% console %>

<h2>New Post</h2>

This will render a console inside your view. You don't need to care about the location of the console call; it won't be rendered on the spot of its invocation but next to your HTML content.


How do you set the EditText keyboard to only consist of numbers on Android?

For the EditText if we specify,


only numbers can be got. But if you use,


along with the numbers it can accept special characters like ;,/". etc.

C Program to find day of week given date

Program to calculate the day on a given date by User

void main()
int dd=0,mm=0,i=0,yy=0,odd1=0,todd=0;//variable declaration for inputing the date
int remyr=0,remyr1=0,lyrs=0,oyrs=0,cyr=0,upyr=0,leap=0;//variable declaration for calculation of odd days
int montharr[12]={31,28,31,30,31,30,31,31,30,31,30,31};//array of month days
printf("Enter the date as DD-MM-YY for which you want to know the day\t:");
scanf("%d%d%d",&dd,&mm,&yy);  //input the date
check out correct date or not?
        //its the leap year

            printf("You have entered wrong date");
    else if(dd>28&&mm==2)
        //not the leap year
        printf("You have entered wrong date");

else if(yy%4==0)
    //again leap year
        printf("You have entered wrong date");

else if(dd>28&&mm==2)
    //not the leap year
    printf("You have entered wrong date");

//if the leap year feb month contains 29 days

//check date,month,year should not be beyond the limits

if((mm>12)||(dd>31)|| (yy>5000))
    printf("Your date is wrong");

//odd months should not contain more than 31 days
if((dd>31 && (mm == 1||mm==3||mm==5||mm==7||mm==8||mm==10||mm==12)))
    printf("Your date is wrong");

//even months should not contains more than 30 days

if((dd>30 && (mm == 4||mm==6||mm==9||mm==11)))
    printf("Your date is wrong");


//logic to calculate odd days.....
printf("\nYou have entered date: %d-%d-%d ",dd,mm,yy);

else if(cyr==0 && remyr>0)

else if(cyr==1)
else if(cyr==2)
else if(cyr==3)

        todd=todd%7;    //total odd days gives the re quired day....
    printf("\n\nThe day on %d-%d-%d :",dd,mm,yy);


Show or hide element in React

<style type="text/css">
    .hidden { display:none; }
render: function() {
    return (
      <div className={this.props.shouldHide ? 'hidden' : ''}>
        This will be hidden if you set <tt>props.shouldHide</tt> 
        to something truthy.

// or in more modern JS and stateless react
const Example = props => <div className={props.shouldHide}/>Hello</div>

How can I prevent the backspace key from navigating back?

    document.onkeydown = function (e) {    
        if ((e.keyCode==8  ||  e.keyCode==13) &&
            ( != "TEXTAREA") && 
            ( != "INPUT")) { 
            return false;

How can I send large messages with Kafka (over 15MB)?

The answer from @laughing_man is quite accurate. But still, I wanted to give a recommendation which I learned from Kafka expert Stephane Maarek.

Kafka isn’t meant to handle large messages.

Your API should use cloud storage (Ex AWS S3), and just push to Kafka or any message broker a reference of S3. You must find somewhere to persist your data, maybe it’s a network drive, maybe it’s whatever, but it shouldn't be message broker.

Now, if you don’t want to go with the above solution

The message max size is 1MB (the setting in your brokers is called message.max.bytes) Apache Kafka. If you really needed it badly, you could increase that size and make sure to increase the network buffers for your producers and consumers.

And if you really care about splitting your message, make sure each message split has the exact same key so that it gets pushed to the same partition, and your message content should report a “part id” so that your consumer can fully reconstruct the message.

You can also explore compression, if your message is text-based (gzip, snappy, lz4 compression) which may reduce the data size, but not magically.

Again, you have to use an external system to store that data and just push an external reference to Kafka. That is a very common architecture and one you should go with and widely accepted.

Keep that in mind Kafka works best only if the messages are huge in amount but not in size.


Best way to combine two or more byte arrays in C#

Can use generics to combine arrays. Following code can easily be expanded to three arrays. This way you never need to duplicate code for different type of arrays. Some of the above answers seem overly complex to me.

private static T[] CombineTwoArrays<T>(T[] a1, T[] a2)
        T[] arrayCombined = new T[a1.Length + a2.Length];
        Array.Copy(a1, 0, arrayCombined, 0, a1.Length);
        Array.Copy(a2, 0, arrayCombined, a1.Length, a2.Length);
        return arrayCombined;

How to delete migration files in Rails 3

Another way to delete the migration:

$ rails d migration SameMigrationNameAsUsedToGenerate

Use it before rake db:migrate is executed because changes in database will stay forever :) - or remove changes in Database manually

How to access session variables from any class in ASP.NET?

(Updated for completeness)
You can access session variables from any page or control using Session["loginId"] and from any class (e.g. from inside a class library), using System.Web.HttpContext.Current.Session["loginId"].

But please read on for my original answer...

I always use a wrapper class around the ASP.NET session to simplify access to session variables:

public class MySession
    // private constructor
    private MySession()
      Property1 = "default value";

    // Gets the current session.
    public static MySession Current
        MySession session =
        if (session == null)
          session = new MySession();
          HttpContext.Current.Session["__MySession__"] = session;
        return session;

    // **** add your session properties here, e.g like this:
    public string Property1 { get; set; }
    public DateTime MyDate { get; set; }
    public int LoginId { get; set; }

This class stores one instance of itself in the ASP.NET session and allows you to access your session properties in a type-safe way from any class, e.g like this:

int loginId = MySession.Current.LoginId;

string property1 = MySession.Current.Property1;
MySession.Current.Property1 = newValue;

DateTime myDate = MySession.Current.MyDate;
MySession.Current.MyDate = DateTime.Now;

This approach has several advantages:

  • it saves you from a lot of type-casting
  • you don't have to use hard-coded session keys throughout your application (e.g. Session["loginId"]
  • you can document your session items by adding XML doc comments on the properties of MySession
  • you can initialize your session variables with default values (e.g. assuring they are not null)

check if jquery has been loaded, then load it if false

Old post but I made an good solution what is tested on serval places.


(function(url, position, callback){
    // default values
    url = url || '';
    position = position || 0;

    // Check is jQuery exists
    if (!window.jQuery) {
        // Initialize <head>
        var head = document.getElementsByTagName('head')[0];
        // Create <script> element
        var script = document.createElement("script");
        // Append URL
        script.src = url;
        // Append type
        script.type = 'text/javascript';
        // Append script to <head>
        // Move script on proper position

        script.onload = function(){
            if(typeof callback == 'function') {
    } else {
        if(typeof callback == 'function') {
}('', 5, function($){ 

At GitHub is better explanation but generaly this function you can add anywhere in your HTML code and you will initialize jquery if is not already loaded.

What does 'COLLATE SQL_Latin1_General_CP1_CI_AS' do?

It sets how the database server sorts (compares pieces of text). in this case:


breaks up into interesting parts:

  1. latin1 makes the server treat strings using charset latin 1, basically ascii
  2. CP1 stands for Code Page 1252
  3. CI case insensitive comparisons so 'ABC' would equal 'abc'
  4. AS accent sensitive, so 'ü' does not equal 'u'

P.S. For more detailed information be sure to read @solomon-rutzky's answer.

Disable clipboard prompt in Excel VBA on workbook close

proposed solution edit works if you replace the row

Set rDst = ThisWorkbook.Sheets("SomeSheet").Cells("YourCell").Resize(rSrc.Rows.Count, rSrc.Columns.Count)


Set rDst = ThisWorkbook.Sheets("SomeSheet").Range("YourRange").Resize(rSrc.Rows.Count, rSrc.Columns.Count)

Merge development branch with master

This is how I usually do it. First, sure that you are ready to merge your changes into master.

  1. Check if development is up to date with the latest changes from your remote server with a git fetch
  2. Once the fetch is completed git checkout master.
  3. Ensure the master branch has the latest updates by executing git pull
  4. Once the preparations have been completed, you can start the merge with git merge development
  5. Push the changes with git push -u origin master and you are done.

You can find more into about git merging in the article.

How to support different screen size in android

Beginning with Android 3.2 (API level 13), size groups (folders small, normal, large, xlarge) are deprecated in favor of a new technique for managing screen sizes based on the available screen width.

There are different resource configurations that you can specify based on the space available for your layout:

1) Smallest Width - The fundamental size of a screen, as indicated by the shortest dimension of the available screen area.

Qualifier Value: sw'dp value'dp

Eg. res/sw600dp/layout.xml -> will be used for all screen sizes bigger or equal to 600dp. This does not take the device orientation into account.

2) Available Screen Width - Specifies a minimum available width in dp units at which the resources should be used.

Qualifier Value: w'dp value'dp

Eg. res/w600dp/layout.xml -> will be used for all screens, which width is greater than or equal to 600dp.

3) Available Screen Height - Specifies a minimum screen height in dp units at which the resources should be used.

Qualifier Value: h'dp value'dp

Eg. res/h600dp/layout.xml -> will be used for all screens, which height is greater than or equal to 600dp.

So at the end your folder structure might look like this:

res/layout/layout.xml -> for handsets (smaller than 600dp available width)
res/layout-sw600dp/layout.xml -> for 7” tablets (600dp wide and bigger)
res/layout-sw720dp/layout.xml -> for 10” tablets (720dp wide and bigger)

For more information please read the official documentation:

How to hide the Google Invisible reCAPTCHA badge

this does not disable the spam checking

div.g-recaptcha > div.grecaptcha-badge {
    width:0 !important;

Java ElasticSearch None of the configured nodes are available

You should check the node's port, you could do it using head. These ports are not same. Example,

The web URL you can open is localhost:9200, but the node's port is 9300, so none of the configured nodes are available if you use the 9200 as the port.

Console logging for react?

If you want to log inside JSX you can create a dummy component
which plugs where you wish to log:

const Console = prop => (
  ,null // ? React components must return something 

// Some component with JSX and a logger inside
const App = () => 
    <p>imagine this is some component</p>
    <Console log='foo' />
    <p>imagine another component</p>
    <Console warn='bar' />

// Render 
  <App />,
<script src=""></script>
<script src=""></script>
<div id="react"></div>

Android sqlite how to check if a record exists

These are all good answers, however many forget to close the cursor and database. If you don't close the cursor or database you may run in to memory leaks.

You can get an error when searching by String that contains non alpha/numeric characters. For example: "1a5f9ea3-ec4b-406b-a567-e6927640db40". Those dashes (-) will cause an unrecognized token error. You can overcome this by putting the string in an array. So make it a habit to query like this:

public boolean hasObject(String id) {
    SQLiteDatabase db = getWritableDatabase();
    String selectString = "SELECT * FROM " + _TABLE + " WHERE " + _ID + " =?";

    // Add the String you are searching by here. 
    // Put it in an array to avoid an unrecognized token error 
    Cursor cursor = db.rawQuery(selectString, new String[] {id}); 

    boolean hasObject = false;
        hasObject = true;

        //region if you had multiple records to check for, use this region. 

        int count = 0;
        //here, count is records found
        Log.d(TAG, String.format("%d records found", count));



    cursor.close();          // Dont forget to close your cursor
    db.close();              //AND your Database!
    return hasObject;

Typescript react - Could not find a declaration file for module ''react-materialize'. 'path/to/module-name.js' implicitly has an any type

in 2021 to create .d.ts file manually, you just need to do the following:

1- enter src folder

2- create global.d.ts file

3-declare modules in it like:

declare module 'module-name';

i answred it here before and it was nice

Simple way to count character occurrences in a string

You can look at sorting the string -- treat it as a char array -- and then do a modified binary search which counts occurrences? But I agree with @tofutim that traversing it is the most efficient -- O(N) versus O(N * logN) + O(logN)

Regex to Match Symbols: !$%^&*()_+|~-=`{}[]:";'<>?,./

The regular expression for this is really simple. Just use a character class. The hyphen is a special character in character classes, so it needs to be first:


You also need to escape the other regular expression metacharacters.

Edit: The hyphen is special because it can be used to represent a range of characters. This same character class can be simplified with ranges to this:


There are three ranges. '$' to '/', ':' to '?', and '{' to '~'. the last string of characters can't be represented more simply with a range: !"^_`[].

Use an ACSII table to find ranges for character classes.

Merging a lot of data.frames

Put them into a list and use merge with Reduce

Reduce(function(x, y) merge(x, y, all=TRUE), list(df1, df2, df3))
#    id v1 v2 v3
# 1   1  1 NA NA
# 2  10  4 NA NA
# 3   2  3  4 NA
# 4  43  5 NA NA
# 5  73  2 NA NA
# 6  23 NA  2  1
# 7  57 NA  3 NA
# 8  62 NA  5  2
# 9   7 NA  1 NA
# 10 96 NA  6 NA

You can also use this more concise version:

Reduce(function(...) merge(..., all=TRUE), list(df1, df2, df3))

Archive the artifacts in Jenkins

Your understanding is correct, an artifact in the Jenkins sense is the result of a build - the intended output of the build process.

A common convention is to put the result of a build into a build, target or bin directory.

The Jenkins archiver can use globs (target/*.jar) to easily pick up the right file even if you have a unique name per build.

Should URL be case sensitive?

the question is should the url be case sensitive?

I see no use, or good practice behind case sensitive URL's. It stupid, it sucks and should be avoided at all times.

Just to back up my opinion, when someone asks what URL, how could you explain what characters of the URL are Upper or Lower case? That's nonsense and should no one ever tell you otherwise.

Android Get Current timestamp?

From developers blog:

System.currentTimeMillis() is the standard "wall" clock (time and date) expressing milliseconds since the epoch. The wall clock can be set by the user or the phone network (see setCurrentTimeMillis(long)), so the time may jump backwards or forwards unpredictably. This clock should only be used when correspondence with real-world dates and times is important, such as in a calendar or alarm clock application. Interval or elapsed time measurements should use a different clock. If you are using System.currentTimeMillis(), consider listening to the ACTION_TIME_TICK, ACTION_TIME_CHANGED and ACTION_TIMEZONE_CHANGED Intent broadcasts to find out when the time changes.

How to bundle an Angular app for production

Angular 2 with Webpack (without CLI setup)

1- The tutorial by the Angular2 team

The Angular2 team published a tutorial for using Webpack

I created and placed the files from the tutorial in a small GitHub seed project. So you can quickly try the workflow.


  • npm install

  • npm start. For development. This will create a virtual "dist" folder that will be livereloaded at your localhost address.

  • npm run build. For production. "This will create a physical "dist" folder version than can be sent to a webserver. The dist folder is 7.8MB but only 234KB is actually required to load the page in a web browser.

2 - A Webkit starter kit

This Webpack Starter Kit offers some more testing features than the above tutorial and seem quite popular.

How to get "GET" request parameters in JavaScript?

You can use the URL to acquire the GET variables. In particular, gives everything after (and including) the '?'. You can read more about window.location here.

How can I remove a style added with .css() function?


there is native API for that

Submit form using <a> tag

You can use hidden submit button and click it using java script/jquery like this:

  <form id="contactForm" method="post" class="contact-form">

        <button type="submit" id="submitBtn" style="display:none;" data-validate="contact-form">Hidden Button</button>
        <a href="javascript:;" class="myClass" onclick="$('#submitBtn').click();">Submit</a>


Where/How to getIntent().getExtras() in an Android Fragment?

What I tend to do, and I believe this is what Google intended for developers to do too, is to still get the extras from an Intent in an Activity and then pass any extra data to fragments by instantiating them with arguments.

There's actually an example on the Android dev blog that illustrates this concept, and you'll see this in several of the API demos too. Although this specific example is given for API 3.0+ fragments, the same flow applies when using FragmentActivity and Fragment from the support library.

You first retrieve the intent extras as usual in your activity and pass them on as arguments to the fragment:

public static class DetailsActivity extends FragmentActivity {

    protected void onCreate(Bundle savedInstanceState) {

        // (omitted some other stuff)

        if (savedInstanceState == null) {
            // During initial setup, plug in the details fragment.
            DetailsFragment details = new DetailsFragment();
          , details).commit();

In stead of directly invoking the constructor, it's probably easier to use a static method that plugs the arguments into the fragment for you. Such a method is often called newInstance in the examples given by Google. There actually is a newInstance method in DetailsFragment, so I'm unsure why it isn't used in the snippet above...

Anyways, all extras provided as argument upon creating the fragment, will be available by calling getArguments(). Since this returns a Bundle, its usage is similar to that of the extras in an Activity.

public static class DetailsFragment extends Fragment {
     * Create a new instance of DetailsFragment, initialized to
     * show the text at 'index'.
    public static DetailsFragment newInstance(int index) {
        DetailsFragment f = new DetailsFragment();

        // Supply index input as an argument.
        Bundle args = new Bundle();
        args.putInt("index", index);

        return f;

    public int getShownIndex() {
        return getArguments().getInt("index", 0);

    // (other stuff omitted)


The ORDER BY clause is invalid in views, inline functions, derived tables, subqueries, and common table expressions


Surprisingly makes it work, what a strange feature.

A bigger example with a CTE as a way to temporarily "store" a long query to re-order it later:

;WITH cte AS (
    SELECT .....long select statement here....

    ( -- necessary to nest selects for union to work with where & order clauses
        SELECT * FROM cte WHERE cte.MainCol= 1 ORDER BY cte.ColX asc OFFSET 0 ROWS 
    ) first
        SELECT * FROM cte WHERE cte.MainCol = 0 ORDER BY cte.ColY desc OFFSET 0 ROWS 
    ) last
) as unionized
ORDER BY unionized.MainCol desc -- all rows ordered by this one
OFFSET @pPageSize * @pPageOffset ROWS -- params from stored procedure for pagination, not relevant to example
FETCH FIRST @pPageSize ROWS ONLY -- params from stored procedure for pagination, not relevant to example

So we get all results ordered by MainCol

But the results with MainCol = 1 get ordered by ColX

And the results with MainCol = 0 get ordered by ColY

How do I fix a NoSuchMethodError?

I had the same error:

  Exception in thread "main" java.lang.NoSuchMethodError: com.fasterxml.jackson.core.JsonGenerator.writeStartObject(Ljava/lang/Object;)V
        at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(
        at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(
        at com.fasterxml.jackson.databind.ObjectMapper._configAndWriteValue(
        at com.fasterxml.jackson.databind.ObjectMapper.writeValueAsString(

To solve it I checked, firstly, Module Dependency Diagram (click in your POM the combination -> Ctrl+Alt+Shift+U or right click in your POM -> Maven -> Show dependencies) to understand where exactly was the conflict between libraries (Intelij IDEA). In my particular case, I had different versions of Jackson dependencies.

enter image description here enter image description here

1) So, I added directly in my POM of the project explicitly the highest version - 2.8.7 of these two.

In properties:


And as dependency:


2) But also it can be solved using Dependency Exclusions.

By the same principle as below in example:


Dependency with unwanted version will be excluded from your project.

How to use and style new AlertDialog from appCompat 22.1 and above

To use a theme for all the application, and don't use the second parameter to style your Dialog

<style name="MyTheme" parent="Base.Theme.AppCompat.Light">
    <item name="alertDialogTheme">@style/dialog</item>
    <item name="colorAccent">@color/accent</item>

<style name="dialog" parent="Base.Theme.AppCompat.Light.Dialog.Alert">
    <item name="colorAccent">@color/accent</item>

On my app using a color accent in theme don't show the alertDialog's buttons with the theme colorAccent I have to add a dialog style in the theme.

Where to declare variable in react js

Using ES6 syntax in React does not bind this to user-defined functions however it will bind this to the component lifecycle methods.

So the function that you declared will not have the same context as the class and trying to access this will not give you what you are expecting.

For getting the context of class you have to bind the context of class to the function or use arrow functions.

Method 1 to bind the context:

class MyContainer extends Component {

    constructor(props) {
        this.onMove = this.onMove.bind(this);
        this.testVarible= "this is a test";

    onMove() {

Method 2 to bind the context:

class MyContainer extends Component {

    constructor(props) {
        this.testVarible= "this is a test";

    onMove = () => {

Method 2 is my preferred way but you are free to choose your own.

Update: You can also create the properties on class without constructor:

class MyContainer extends Component {

    testVarible= "this is a test";

    onMove = () => {

Note If you want to update the view as well, you should use state and setState method when you set or change the value.


class MyContainer extends Component {

    state = { testVarible: "this is a test" };

    onMove = () => {
        this.setState({ testVarible: "new value" });

How do I set the path to a DLL file in Visual Studio?

  1. Go to project properties (Alt+F7)
  2. Under Debugging, look to the right
  3. There's an Environment field.
  4. Add your relative path there (relative to vcproj folder) i.e. ..\some-framework\lib by appending PATH=%PATH%;$(ProjectDir)\some-framework\lib or prepending to the path PATH=C:\some-framework\lib;%PATH%
  5. Hit F5 (debug) again and it should work.

Simplest way to detect a pinch

Unfortunately, detecting pinch gestures across browsers is a not as simple as one would hope, but HammerJS makes it a lot easier!

Check out the Pinch Zoom and Pan with HammerJS demo. This example has been tested on Android, iOS and Windows Phone.

You can find the source code at Pinch Zoom and Pan with HammerJS.

For your convenience, here is the source code:

<!DOCTYPE html>_x000D_
  <meta charset="utf-8">_x000D_
  <meta name="viewport"_x000D_
        content="user-scalable=no, width=device-width, initial-scale=1, maximum-scale=1">_x000D_
  <title>Pinch Zoom</title>_x000D_
    <div style="height:150px;background-color:#eeeeee">_x000D_
      Ignore this area. Space is needed to test on the iPhone simulator as pinch simulation on the_x000D_
      iPhone simulator requires the target to be near the middle of the screen and we only respect_x000D_
      touch events in the image area. This space is not needed in production._x000D_
      .pinch-zoom-container {_x000D_
        overflow: hidden;_x000D_
        height: 300px;_x000D_
      .pinch-zoom-image {_x000D_
        width: 100%;_x000D_
    <script src=""></script>_x000D_
      var MIN_SCALE = 1; // 1=scaling when first loaded_x000D_
      var MAX_SCALE = 64;_x000D_
      // HammerJS fires "pinch" and "pan" events that are cumulative in nature and not_x000D_
      // deltas. Therefore, we need to store the "last" values of scale, x and y so that we can_x000D_
      // adjust the UI accordingly. It isn't until the "pinchend" and "panend" events are received_x000D_
      // that we can set the "last" values._x000D_
      // Our "raw" coordinates are not scaled. This allows us to only have to modify our stored_x000D_
      // coordinates when the UI is updated. It also simplifies our calculations as these_x000D_
      // coordinates are without respect to the current scale._x000D_
      var imgWidth = null;_x000D_
      var imgHeight = null;_x000D_
      var viewportWidth = null;_x000D_
      var viewportHeight = null;_x000D_
      var scale = null;_x000D_
      var lastScale = null;_x000D_
      var container = null;_x000D_
      var img = null;_x000D_
      var x = 0;_x000D_
      var lastX = 0;_x000D_
      var y = 0;_x000D_
      var lastY = 0;_x000D_
      var pinchCenter = null;_x000D_
      // We need to disable the following event handlers so that the browser doesn't try to_x000D_
      // automatically handle our image drag gestures._x000D_
      var disableImgEventHandlers = function () {_x000D_
        var events = ['onclick', 'onmousedown', 'onmousemove', 'onmouseout', 'onmouseover',_x000D_
                      'onmouseup', 'ondblclick', 'onfocus', 'onblur'];_x000D_
        events.forEach(function (event) {_x000D_
          img[event] = function () {_x000D_
            return false;_x000D_
      // Traverse the DOM to calculate the absolute position of an element_x000D_
      var absolutePosition = function (el) {_x000D_
        var x = 0,_x000D_
          y = 0;_x000D_
        while (el !== null) {_x000D_
          x += el.offsetLeft;_x000D_
          y += el.offsetTop;_x000D_
          el = el.offsetParent;_x000D_
        return { x: x, y: y };_x000D_
      var restrictScale = function (scale) {_x000D_
        if (scale < MIN_SCALE) {_x000D_
          scale = MIN_SCALE;_x000D_
        } else if (scale > MAX_SCALE) {_x000D_
          scale = MAX_SCALE;_x000D_
        return scale;_x000D_
      var restrictRawPos = function (pos, viewportDim, imgDim) {_x000D_
        if (pos < viewportDim/scale - imgDim) { // too far left/up?_x000D_
          pos = viewportDim/scale - imgDim;_x000D_
        } else if (pos > 0) { // too far right/down?_x000D_
          pos = 0;_x000D_
        return pos;_x000D_
      var updateLastPos = function (deltaX, deltaY) {_x000D_
        lastX = x;_x000D_
        lastY = y;_x000D_
      var translate = function (deltaX, deltaY) {_x000D_
        // We restrict to the min of the viewport width/height or current width/height as the_x000D_
        // current width/height may be smaller than the viewport width/height_x000D_
        var newX = restrictRawPos(lastX + deltaX/scale,_x000D_
                                  Math.min(viewportWidth, curWidth), imgWidth);_x000D_
        x = newX;_x000D_ = Math.ceil(newX*scale) + 'px';_x000D_
        var newY = restrictRawPos(lastY + deltaY/scale,_x000D_
                                  Math.min(viewportHeight, curHeight), imgHeight);_x000D_
        y = newY;_x000D_ = Math.ceil(newY*scale) + 'px';_x000D_
      var zoom = function (scaleBy) {_x000D_
        scale = restrictScale(lastScale*scaleBy);_x000D_
        curWidth = imgWidth*scale;_x000D_
        curHeight = imgHeight*scale;_x000D_
_x000D_ = Math.ceil(curWidth) + 'px';_x000D_ = Math.ceil(curHeight) + 'px';_x000D_
        // Adjust margins to make sure that we aren't out of bounds_x000D_
        translate(0, 0);_x000D_
      var rawCenter = function (e) {_x000D_
        var pos = absolutePosition(container);_x000D_
        // We need to account for the scroll position_x000D_
        var scrollLeft = window.pageXOffset ? window.pageXOffset : document.body.scrollLeft;_x000D_
        var scrollTop = window.pageYOffset ? window.pageYOffset : document.body.scrollTop;_x000D_
        var zoomX = -x + ( - pos.x + scrollLeft)/scale;_x000D_
        var zoomY = -y + ( - pos.y + scrollTop)/scale;_x000D_
        return { x: zoomX, y: zoomY };_x000D_
      var updateLastScale = function () {_x000D_
        lastScale = scale;_x000D_
      var zoomAround = function (scaleBy, rawZoomX, rawZoomY, doNotUpdateLast) {_x000D_
        // Zoom_x000D_
        // New raw center of viewport_x000D_
        var rawCenterX = -x + Math.min(viewportWidth, curWidth)/2/scale;_x000D_
        var rawCenterY = -y + Math.min(viewportHeight, curHeight)/2/scale;_x000D_
        // Delta_x000D_
        var deltaX = (rawCenterX - rawZoomX)*scale;_x000D_
        var deltaY = (rawCenterY - rawZoomY)*scale;_x000D_
        // Translate back to zoom center_x000D_
        translate(deltaX, deltaY);_x000D_
        if (!doNotUpdateLast) {_x000D_
      var zoomCenter = function (scaleBy) {_x000D_
        // Center of viewport_x000D_
        var zoomX = -x + Math.min(viewportWidth, curWidth)/2/scale;_x000D_
        var zoomY = -y + Math.min(viewportHeight, curHeight)/2/scale;_x000D_
        zoomAround(scaleBy, zoomX, zoomY);_x000D_
      var zoomIn = function () {_x000D_
      var zoomOut = function () {_x000D_
      var onLoad = function () {_x000D_
        img = document.getElementById('pinch-zoom-image-id');_x000D_
        container = img.parentElement;_x000D_
        imgWidth = img.width;_x000D_
        imgHeight = img.height;_x000D_
        viewportWidth = img.offsetWidth;_x000D_
        scale = viewportWidth/imgWidth;_x000D_
        lastScale = scale;_x000D_
        viewportHeight = img.parentElement.offsetHeight;_x000D_
        curWidth = imgWidth*scale;_x000D_
        curHeight = imgHeight*scale;_x000D_
        var hammer = new Hammer(container, {_x000D_
          domEvents: true_x000D_
          enable: true_x000D_
        hammer.on('pan', function (e) {_x000D_
          translate(e.deltaX, e.deltaY);_x000D_
        hammer.on('panend', function (e) {_x000D_
        hammer.on('pinch', function (e) {_x000D_
          // We only calculate the pinch center on the first pinch event as we want the center to_x000D_
          // stay consistent during the entire pinch_x000D_
          if (pinchCenter === null) {_x000D_
            pinchCenter = rawCenter(e);_x000D_
            var offsetX = pinchCenter.x*scale - (-x*scale + Math.min(viewportWidth, curWidth)/2);_x000D_
            var offsetY = pinchCenter.y*scale - (-y*scale + Math.min(viewportHeight, curHeight)/2);_x000D_
            pinchCenterOffset = { x: offsetX, y: offsetY };_x000D_
          // When the user pinch zooms, she/he expects the pinch center to remain in the same_x000D_
          // relative location of the screen. To achieve this, the raw zoom center is calculated by_x000D_
          // first storing the pinch center and the scaled offset to the current center of the_x000D_
          // image. The new scale is then used to calculate the zoom center. This has the effect of_x000D_
          // actually translating the zoom center on each pinch zoom event._x000D_
          var newScale = restrictScale(scale*e.scale);_x000D_
          var zoomX = pinchCenter.x*newScale - pinchCenterOffset.x;_x000D_
          var zoomY = pinchCenter.y*newScale - pinchCenterOffset.y;_x000D_
          var zoomCenter = { x: zoomX/newScale, y: zoomY/newScale };_x000D_
          zoomAround(e.scale, zoomCenter.x, zoomCenter.y, true);_x000D_
        hammer.on('pinchend', function (e) {_x000D_
          pinchCenter = null;_x000D_
        hammer.on('doubletap', function (e) {_x000D_
          var c = rawCenter(e);_x000D_
          zoomAround(2, c.x, c.y);_x000D_
    <button onclick="zoomIn()">Zoom In</button>_x000D_
    <button onclick="zoomOut()">Zoom Out</button>_x000D_
    <div class="pinch-zoom-container">_x000D_
      <img id="pinch-zoom-image-id" class="pinch-zoom-image" onload="onLoad()"_x000D_

How to avoid "RuntimeError: dictionary changed size during iteration" error?

For situations like this, i like to make a deep copy and loop through that copy while modifying the original dict.

If the lookup field is within a list, you can enumerate in the for loop of the list and then specify the position as index to access the field in the original dict.

html script src="" triggering redirection with button

First you are linking the file that is here:

<script src="../Script/login.js"> 

Which would lead the website to a file in the Folder Script, but then in the second paragraph you are saying that the folder name is

and also i have onother folder named scripts that contains the the following login.js file

So, this won't work! Because you are not accessing the correct file. To do that please write the code as

<script src="/script/login.js"></script>

Try removing the .. from the beginning of the code too.

This way, you'll reach the js file where the function would run!

Just to make sure:

Just to make sure that the files are attached the HTML DOM, then please open Developer Tools (F12) and in the network workspace note each request that the browser makes to the server. This way you will learn which files were loaded and which weren't, and also why they were not!

Good luck.

Decimal to Hexadecimal Converter in Java

The following converts decimal to Hexa Decimal with Time Complexity : O(n) Linear Time with out any java inbuilt function

private static String decimalToHexaDecimal(int N) {
    char hexaDecimals[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
    StringBuilder builder = new StringBuilder();
    int base= 16;
    while (N != 0) {
        int reminder = N % base;
        N = N / base;

    return builder.reverse().toString();

Interpreting "condition has length > 1" warning from `if` function

Here's an easy way without ifelse:


An example:

a <- c(0, 1, 0, 0, 1, 1, 0, 1)


[1] 1.00 0.25 1.00 1.00 0.25 0.25 1.00 0.25

Get record counts for all tables in MySQL database

If you want the exact numbers, use the following ruby script. You need Ruby and RubyGems.

Install following Gems:

$> gem install dbi
$> gem install dbd-mysql

File: count_table_records.rb

require 'rubygems'
require 'dbi'

db_handler = DBI.connect('DBI:Mysql:database_name:localhost', 'username', 'password')

# Collect all Tables
sql_1 = db_handler.prepare('SHOW tables;')
tables = { |row| row[0]}

tables.each do |table_name|
  sql_2 = db_handler.prepare("SELECT count(*) FROM #{table_name};")
  sql_2.each do |row|
    puts "Table #{table_name} has #{row[0]} rows."


Go back to the command-line:

$> ruby count_table_records.rb


Table users has 7328974 rows.

Creating dummy variables in pandas for python

When I think of dummy variables I think of using them in the context of OLS regression, and I would do something like this:

import numpy as np
import pandas as pd
import statsmodels.api as sm

my_data = np.array([[5, 'a', 1],
                    [3, 'b', 3],
                    [1, 'b', 2],
                    [3, 'a', 1],
                    [4, 'b', 2],
                    [7, 'c', 1],
                    [7, 'c', 1]])                

df = pd.DataFrame(data=my_data, columns=['y', 'dummy', 'x'])
just_dummies = pd.get_dummies(df['dummy'])

step_1 = pd.concat([df, just_dummies], axis=1)      
step_1.drop(['dummy', 'c'], inplace=True, axis=1)
# to run the regression we want to get rid of the strings 'a', 'b', 'c' (obviously)
# and we want to get rid of one dummy variable to avoid the dummy variable trap
# arbitrarily chose "c", coefficients on "a" an "b" would show effect of "a" and "b"
# relative to "c"
step_1 = step_1.applymap( 

result = sm.OLS(step_1['y'], sm.add_constant(step_1[['x', 'a', 'b']])).fit()
print result.summary()

How do I instantiate a Queue object in java?

A Queue is an interface, which means you cannot construct a Queue directly.

The best option is to construct off a class that already implements the Queue interface, like one of the following: AbstractQueue, ArrayBlockingQueue, ArrayDeque, ConcurrentLinkedQueue, DelayQueue, LinkedBlockingQueue, LinkedList, PriorityBlockingQueue, PriorityQueue, or SynchronousQueue.

An alternative is to write your own class which implements the necessary Queue interface. It is not needed except in those rare cases where you wish to do something special while providing the rest of your program with a Queue.

public class MyQueue<T extends Tree> implements Queue<T> {
   public T element() {
     ... your code to return an element goes here ...

   public boolean offer(T element) {
     ... your code to accept a submission offer goes here ...

   ... etc ...

An even less used alternative is to construct an anonymous class that implements Queue. You probably don't want to do this, but it's listed as an option for the sake of covering all the bases.

new Queue<Tree>() {
   public Tree element() {

   public boolean offer(Tree element) {

how to create 100% vertical line in css

I've used min-height: 100vh; with great success on some of my projects. See example.


Disclaimer: I'm not a MySQL expert ... but this is my understanding of the issues.

I think TEXT is stored outside the mysql row, while I think VARCHAR is stored as part of the row. There is a maximum row length for mysql rows .. so you can limit how much other data you can store in a row by using the VARCHAR.

Also due to VARCHAR forming part of the row, I suspect that queries looking at that field will be slightly faster than those using a TEXT chunk.

What is the best way to modify a list in a 'foreach' loop?

I have written one easy step, but because of this performance will be degraded

Here is my code snippet:-

for (int tempReg = 0; tempReg < reg.Matches(lines).Count; tempReg++)
                                foreach (Match match in reg.Matches(lines))
                                    var aStringBuilder = new StringBuilder(lines);
                                    aStringBuilder.Insert(startIndex, match.ToString().Replace(",", " ");
                                    lines[k] = aStringBuilder.ToString();
                                    tempReg = 0;

JavaScript: Upload file

Pure JS

You can use fetch optionally with await-try-catch

let photo = document.getElementById("image-file").files[0];
let formData = new FormData();
formData.append("photo", photo);
fetch('/upload/image', {method: "POST", body: formData});

async function SavePhoto(inp) 
    let user = { name:'john', age:34 };
    let formData = new FormData();
    let photo = inp.files[0];      
    formData.append("photo", photo);
    formData.append("user", JSON.stringify(user)); 
    const ctrl = new AbortController()    // timeout
    setTimeout(() => ctrl.abort(), 5000);
    try {
       let r = await fetch('/upload/image', 
         {method: "POST", body: formData, signal: ctrl.signal}); 
       console.log('HTTP response code:',r.status); 
    } catch(e) {
       console.log('Huston we have problem...:', e);
<input id="image-file" type="file" onchange="SavePhoto(this)" >
Before selecting the file open chrome console > network tab to see the request details.
<small>Because in this example we send request to the response code will be 404 ofcourse...</small>

(in stack overflow snippets there is problem with error handling, however in <a href="">jsfiddle version</a> for 404 errors 4xx/5xx are <a href="">not throwing</a> at all but we can read response status which contains code)

Old school approach - xhr

let photo = document.getElementById("image-file").files[0];  // file from input
let req = new XMLHttpRequest();
let formData = new FormData();

formData.append("photo", photo);                       "POST", '/upload/image');

function SavePhoto(e) 
    let user = { name:'john', age:34 };
    let xhr = new XMLHttpRequest();
    let formData = new FormData();
    let photo = e.files[0];      
    formData.append("user", JSON.stringify(user));   
    formData.append("photo", photo);
    xhr.onreadystatechange = state => { console.log(xhr.status); } // err handling
    xhr.timeout = 5000;"POST", '/upload/image'); 
<input id="image-file" type="file" onchange="SavePhoto(this)" >
Choose file and open chrome console > network tab to see the request details.
<small>Because in this example we send request to the response code will be 404 ofcourse...</small>

(the stack overflow snippets, has some problem with error handling - the xhr.status is zero (instead of 404) which is similar to situation when we run script from file on <a href="">local disc</a> - so I provide also js fiddle version which shows proper http error code <a href="">here</a>)


  • In server side you can read original file name (and other info) which is automatically included to request by browser in filename formData parameter.
  • You do NOT need to set request header Content-Type to multipart/form-data - this will be set automatically by browser.
  • Instead of /upload/image you can use full address like http://.../upload/image.
  • If you want to send many files in single request use multiple attribute: <input multiple type=... />, and attach all chosen files to formData in similar way (e.g. photo2=...files[2];... formData.append("photo2", photo2);)
  • You can include additional data (json) to request e.g. let user = {name:'john', age:34} in this way: formData.append("user", JSON.stringify(user));
  • You can set timeout: for fetch using AbortController, for old approach by xhr.timeout= milisec
  • This solutions should work on all major browsers.

How to use an image for the background in tkinter?

A simple tkinter code for Python 3 for setting background image .

from tkinter import *
from tkinter import messagebox
top = Tk()

C = Canvas(top, bg="blue", height=250, width=300)
filename = PhotoImage(file = "C:\\Users\\location\\imageName.png")
background_label = Label(top, image=filename), y=0, relwidth=1, relheight=1)


SimpleXML - I/O warning : failed to load external entity

You can also load the content with cURL, if file_get_contents insn't enabled on your server.


$ch = curl_init();  


$output = curl_exec($ch);


$items = simplexml_load_string($output);

reStructuredText tool support

Salvaging (and extending) the list from an old version of the Wikipedia page:



Although the reference implementation of reStructuredText is written in Python, there are reStructuredText parsers in other languages too.

Python - Docutils

The main distribution of reStructuredText is the Python Docutils package. It contains several conversion tools:

  • rst2html - from reStructuredText to HTML
  • rst2xml - from reStructuredText to XML
  • rst2latex - from reStructuredText to LaTeX
  • rst2odt - from reStructuredText to ODF Text (word processor) document.
  • rst2s5 - from reStructuredText to S5, a Simple Standards-based Slide Show System
  • rst2man - from reStructuredText to Man page

Haskell - Pandoc

Pandoc is a Haskell library for converting from one markup format to another, and a command-line tool that uses this library. It can read Markdown and (subsets of) reStructuredText, HTML, and LaTeX, and it can write Markdown, reStructuredText, HTML, LaTeX, ConTeXt, PDF, RTF, DocBook XML, OpenDocument XML, ODT, GNU Texinfo, MediaWiki markup, groff man pages, and S5 HTML slide shows.

There is an Pandoc online tool (POT) to try this library. Unfortunately, compared to the reStructuredText online renderer (ROR),

  • POT truncates input rather more shortly. The POT user must render input in chunks that could be rendered whole by the ROR.
  • POT output lacks the helpful error messages displayed by the ROR (and generated by docutils)

Java - JRst

JRst is a Java reStructuredText parser. It can currently output HTML, XHTML, DocBook xdoc and PDF, BUT seems to have serious problems: neither PDF or (X)HTML generation works using the current full download, result pages in (X)HTML are empty and PDF generation fails on IO problems with XSL files (not bundled??). Note that the original JRst has been removed from the website; a fork is found on GitHub.

Scala - Laika

Laika is a new library for transforming markup languages to other output formats. Currently it supports input from Markdown and reStructuredText and produce HTML output. The library is written in Scala but should be also usable from Java.





The Nim compiler features the commands rst2htmland rst2tex which transform reStructuredText files to HTML and TeX files. The standard library provides the following modules (used by the compiler) to handle reStructuredText files programmatically:

  • rst - implements a reStructuredText parser
  • rstast - implements an AST for the reStructuredText parser
  • rstgen - implements a generator of HTML/Latex from reStructuredText

Other 3rd party converters

Most (but not all) of these tools are based on Docutils (see above) and provide conversion to or from formats that might not be supported by the main distribution.

From reStructuredText

  • restview - This pip-installable python package requires docutils, which does the actual rendering. restview's major ease-of-use feature is that, when you save changes to your document(s), it automagically re-renders and re-displays them. restview
    1. starts a small web server
    2. calls docutils to render your document(s) to HTML
    3. calls your device's browser to display the output HTML.
  • rst2pdf - from reStructuredText to PDF
  • rst2odp - from reStructuredText to ODF Presentation
  • rst2beamer - from reStructuredText to LaTeX beamer Presentation class
  • Wikir - from reStructuredText to a Google (and possibly other) Wiki formats
  • rst2qhc - Convert a collection of reStructuredText files into a Qt (toolkit) Help file and (optional) a Qt Help Project file

To reStructuredText

  • xml2rst is an XSLT script to convert Docutils internal XML representation (back) to reStructuredText
  • Pandoc (see above) can also convert from Markdown, HTML and LaTeX to reStructuredText
  • db2rst is a simple and limited DocBook to reStructuredText translator
  • pod2rst - convert .pod files to reStructuredText files


Some projects use reStructuredText as a baseline to build on, or provide extra functionality extending the utility of the reStructuredText tools.


The Sphinx documentation generator translates a set of reStructuredText source files into various output formats, automatically producing cross-references, indices etc.


rest2web is a simple tool that lets you build your website from a single template (or as many as you want), and keep the contents in reStructuredText.


Pygments is a generic syntax highlighter for general use in all kinds of software such as forum systems, Wikis or other applications that need to prettify source code. See Using Pygments in reStructuredText documents.

Free Editors

While any plain text editor is suitable to write reStructuredText documents, some editors have better support than others.


The Emacs support via rst-mode comes as part of the Docutils package under /docutils/tools/editors/emacs/rst.el


The vim-common package for that comes with most GNU/Linux distributions has reStructuredText syntax highlight and indentation support of reStructuredText out of the box:


There is a rst mode for the Jed programmers editor.


gedit, the official text editor of the GNOME desktop environment. There is a gedit reStructuredText plugin.


Geany, a small and lightweight Integrated Development Environment include support for reStructuredText from version 0.12 (October 10, 2007).


Leo, an outlining editor for programmers, supports reStructuredText via rst-plugin or via "@auto-rst" nodes (it's not well-documented, but @auto-rst nodes allow editing rst files directly, parsing the structure into the Leo outline).

It also provides a way to preview the resulting HTML, in a "viewrendered" pane.


The FTE Folding Text Editor - a free (licensed under the GNU GPL) text editor for developers. FTE has a mode for reStructuredText support. It provides color highlighting of basic RSTX elements and special menu that provide easy way to insert most popular RSTX elements to a document.


PyK is a successor of PyEdit and reStInPeace, written in Python with the help of the Qt4 toolkit.


The Eclipse IDE with the ReST Editor plug-in provides support for editing reStructuredText files.


NoTex is a browser based (general purpose) text editor, with integrated project management and syntax highlighting. Plus it enables to write books, reports, articles etc. using rST and convert them to LaTex, PDF or HTML. The PDF files are of high publication quality and are produced via Sphinx with the Texlive LaTex suite.


Notepad++ is a general purpose text editor for Windows. It has syntax highlighting for many languages built-in and support for reStructuredText via a user defined language for reStructuredText.

Visual Studio Code

Visual Studio Code is a general purpose text editor for Windows/macOS/Linux. It has syntax highlighting for many languages built-in and supports reStructuredText via an extension from LeXtudio.

Dedicated reStructuredText Editors

Proprietary editors

Sublime Text

Sublime Text is a completely customizable and extensible source code editor available for Windows, OS X, and Linux. Registration is required for long-term use, but all functions are available in the unregistered version, with occasional reminders to purchase a license. Versions 2 and 3 (currently in beta) support reStructuredText syntax highlighting by default, and several plugins are available through the package manager Package Control to provide snippets and code completion, additional syntax highlighting, conversion to/from RST and other formats, and HTML preview in the browser.

BBEdit / TextWrangler

BBEdit (and its free variant TextWrangler) for Mac can syntax-highlight reStructuredText using this codeless language module.


TextMate, a proprietary general-purpose GUI text editor for Mac OS X, has a bundle for reStructuredText.


Intype is a proprietary text editor for Windows, that support reStructuredText out of the box.

E Text Editor

E is a proprietary Text Editor licensed under the "Open Company License". It supports TextMate's bundles, so it should support reStructuredText the same way TextMate does.


PyCharm (and other IntelliJ platform IDEs?) has ReST/Sphinx support (syntax highlighting, autocomplete and preview).instant preview)


here are some Wiki programs that support the reStructuredText markup as the native markup syntax, or as an add-on:


MediaWiki reStructuredText extension allows for reStructuredText markup in MediaWiki surrounded by <rst> and </rst>.


MoinMoin is an advanced, easy to use and extensible WikiEngine with a large community of users. Said in a few words, it is about collaboration on easily editable web pages.

There is a reStructuredText Parser for MoinMoin.


Trac is an enhanced wiki and issue tracking system for software development projects. There is a reStructuredText Support in Trac.

This Wiki

This Wiki is a Webware for Python Wiki written by Ian Bicking. This wiki uses ReStructuredText for its markup.


rstiki is a minimalist single-file personal wiki using reStructuredText syntax (via docutils) inspired by pwyky. It does not support authorship indication, versioning, hierarchy, chrome/framing/templating or styling. It leverages docutils/reStructuredText as the wiki syntax. As such, it's under 200 lines of code, and in a single file. You put it in a directory and it runs.


Ikiwiki is a wiki compiler. It converts wiki pages into HTML pages suitable for publishing on a website. Ikiwiki stores pages and history in a revision control system such as Subversion or Git. There are many other features, including support for blogging, as well as a large array of plugins. It's reStructuredText plugin, however is somewhat limited and is not recommended as its' main markup language at this time.

Web Services


An Online reStructuredText editor can be used to play with the markup and see the results immediately.

Blogging frameworks


WordPreSt reStructuredText plugin for WordPress. (PHP)


reStructuredText parser plugin for Zine (will become obsolete in version 0.2 when Zine is scheduled to get a native reStructuredText support). Zine is discontinued. (Python)


Pelican is a static blog generator that supports writing articles in ReST. (Python)


Hyde is a static website generator that supports ReST. (Python)


Acrylamid is a static blog generator that supports writing articles in ReST. (Python)


Nikola is a Static Site and Blog Generator that supports ReST. (Python)

ipsum genera

Ipsum genera is a static blog generator written in Nim.


Yozuch is a static blog generator written in Python.


what is the difference between $_SERVER['REQUEST_URI'] and $_GET['q']?

In the context of Drupal, the difference will depend whether clean URLs are on or not.

With them off, $_SERVER['REQUEST_URI'] will have the full path of the page as called w/ /index.php, while $_GET["q"] will just have what is assigned to q.

With them on, they will be nearly identical w/o other arguments, but $_GET["q"] will be missing the leading /. Take a look towards the end of the default .htaccess to see what is going on. They will also differ if additional arguments are passed into the page, eg when a pager is active.

How to check if an object is defined?

If a class type is not defined, you'll get a compiler error if you try to use the class, so in that sense you should have to check.

If you have an instance, and you want to ensure it's not null, simply check for null:

if (value != null)
    // it's not null. 

PostgreSQL Autoincrement

Yes, SERIAL is the equivalent function.

bar varchar);

INSERT INTO foo (bar) values ('blah');
INSERT INTO foo (bar) values ('blah');



SERIAL is just a create table time macro around sequences. You can not alter SERIAL onto an existing column.

Search and replace in bash using regular expressions

These examples also work in bash no need to use sed:

echo ${MYVAR//[0-9]/N}

you can also use the character class bracket expressions

echo ${MYVAR//[[:digit:]]/N}



What @Lanaru wanted to know however, if I understand the question correctly, is why the "full" or PCRE extensions \s\S\w\W\d\D etc don't work as supported in php ruby python etc. These extensions are from Perl-compatible regular expressions (PCRE) and may not be compatible with other forms of shell based regular expressions.

These don't work:

echo ${hello//\d/}

echo $hello | sed 's/\d//g'

output with all literal "d" characters removed


but the following does work as expected

echo $hello | perl -pe 's/\d//g'



Hope that clarifies things a bit more but if you are not confused yet why don't you try this on Mac OS X which has the REG_ENHANCED flag enabled:

echo $MYVAR | grep -o -E '\d'

On most flavours of *nix you will only see the following output:



CSS text-overflow in a table cell?

If you just want the table to auto-layout

Without using max-width, or percentage column widths, or table-layout: fixed etc.

How it works:

Step 1: Just let the table auto-layout do its thing.

When there's one or more columns with a lot of text, it will shrink the other columns as much as possible, then wrap the text of the long columns:

enter image description here

Step 2: Wrap cell contents in a div, then set that div to max-height: 1.1em

(the extra 0.1em is for characters which render a bit below the text base, like the tail of 'g' and 'y')

enter image description here

Step 3: Set title on the divs

This is good for accessibility, and is necessary for the little trick we'll use in a moment.

enter image description here

Step 4: Add a CSS ::after on the div

This is the tricky bit. We set a CSS ::after, with content: attr(title), then position that on top of the div and set text-overflow: ellipsis. I've coloured it red here to make it clear.

(Note how the long column now has a tailing ellipsis)

enter image description here

Step 5: Set the colour of the div text to transparent

And we're done!

enter image description here

Python: One Try Multiple Except

Yes, it is possible.

except FirstException:

except SecondException:

except (ThirdException, FourthException, FifthException) as e:

except Exception:


The "as" keyword is used to assign the error to a variable so that the error can be investigated more thoroughly later on in the code. Also note that the parentheses for the triple exception case are needed in python 3. This page has more info: Catch multiple exceptions in one line (except block)

How to properly apply a lambda function into a pandas data frame column

You need mask:

sample['PR'] = sample['PR'].mask(sample['PR'] < 90, np.nan)

Another solution with loc and boolean indexing:

sample.loc[sample['PR'] < 90, 'PR'] = np.nan


import pandas as pd
import numpy as np

sample = pd.DataFrame({'PR':[10,100,40] })
print (sample)
0   10
1  100
2   40

sample['PR'] = sample['PR'].mask(sample['PR'] < 90, np.nan)
print (sample)
0    NaN
1  100.0
2    NaN
sample.loc[sample['PR'] < 90, 'PR'] = np.nan
print (sample)
0    NaN
1  100.0
2    NaN


Solution with apply:

sample['PR'] = sample['PR'].apply(lambda x: np.nan if x < 90 else x)

Timings len(df)=300k:

sample = pd.concat([sample]*100000).reset_index(drop=True)

In [853]: %timeit sample['PR'].apply(lambda x: np.nan if x < 90 else x)
10 loops, best of 3: 102 ms per loop

In [854]: %timeit sample['PR'].mask(sample['PR'] < 90, np.nan)
The slowest run took 4.28 times longer than the fastest. This could mean that an intermediate result is being cached.
100 loops, best of 3: 3.71 ms per loop

Display Animated GIF

Easiest way - Can be consider the below code

We can take advantage of Imageview setImageResource , refer below code for the same.

The below code can be used to show the image like gif incase if you have the multiple split image of gif. Just split the gif into individual png from a online tool and put image in the drawable like the below order

image_1.png, image_2.png, etc.

Have the handler to change the image dynamically.

int imagePosition = 1;
    Handler handler = new Handler();
        Runnable runnable = new Runnable() {
            public void run() {

    public void updateImage() {

                appInstance.runOnUiThread(new Runnable() {
                    public void run() {
                        int resId = getResources().getIdentifier("image_" + imagePosition, "drawable", appInstance.getPackageName());
    //Consider you have 30 image for the anim
                        if (imagePosition == 30) {
//this make animation play only once

                        } else {
    //You can define your own time based on the animation
                            handler.postDelayed(runnable, 50);

//to make animation to continue use below code and remove above if else
// if (imagePosition == 30)
//imagePosition = 1;
// handler.postDelayed(runnable, 50);

implement time delay in c

you can simply call delay() function. So if you want to delay the process in 3 seconds, call delay(3000)...

Hex colors: Numeric representation for "transparent"?

Very simple: no color, no opacity:

rgba(0, 0, 0, 0);

Angular.js: set element height on page load

A slight improvement to Bizzard's excellent answer. Supports width-offset and/or height-offset on the element, to determine how much will be subtracted from the width/height, and prevents negative dimensions.

 <div resize height-offset="260" width-offset="100">


app.directive('resize', ['$window', function ($window) {
    return function (scope, element) {
        var w = angular.element($window);
        var heightOffset = parseInt(element.attr('height-offset'));
        var widthOffset = parseInt(element.attr('width-offset'));
        var changeHeight = function () {
            if (!isNaN(heightOffset) && w.height() - heightOffset > 0)
                element.css('height', (w.height() - heightOffset) + 'px');
            if (!isNaN(widthOffset) && w.width() - widthOffset > 0)
                element.css('width', (w.width() - widthOffset) + 'px');
        w.bind('resize', function () {

Edit This is actually a silly way of doing it in modern browsers. CSS3 has calc, which allows the calculation to be specified in CSS, like this:

#myDiv {
 width: calc(100% - 200px);
 height: calc(100% - 120px);

How to list only files and not directories of a directory Bash?

{ find . -maxdepth 1 -type f | xargs ls -1t | less; }

added xargs to make it works, and used -1 instead of -l to show only filenames without additional ls info

Get value from hidden field using jQuery

Closing the quotes in var hv = $('#h_v).text(); would help I guess

Concatenating two one-dimensional NumPy arrays

There are several possibilities for concatenating 1D arrays, e.g.,

numpy.r_[a, a],
numpy.stack([a, a]).reshape(-1),
numpy.hstack([a, a]),
numpy.concatenate([a, a])

All those options are equally fast for large arrays; for small ones, concatenate has a slight edge:

enter image description here

The plot was created with perfplot:

import numpy
import perfplot
    setup=lambda n: numpy.random.rand(n),
        lambda a: numpy.r_[a, a],
        lambda a: numpy.stack([a, a]).reshape(-1),
        lambda a: numpy.hstack([a, a]),
        lambda a: numpy.concatenate([a, a]),
    labels=["r_", "stack+reshape", "hstack", "concatenate"],
    n_range=[2 ** k for k in range(19)],

git-diff to ignore ^M

As noted by VonC, this has already been included in git 2.16+. Unfortunately, the name of the option (--ignore-cr-at-eol) differs from the one used by GNU diff that I'm used to (--strip-trailing-cr).

When I was confronted with this problem, my solution was to invoke GNU diff instead of git's built-in diff, because my git is older than 2.16. I did that using this command line:

GIT_EXTERNAL_DIFF='diff -u --strip-trailing-cr "$2" "$5";true;#' git diff --ext-diff

That allows using --strip-trailing-cr and any other GNU diff options.

There's also this other way:

git difftool -y -x 'diff -u --strip-trailing-cr'

but it doesn't use the configured pager settings, which is why I prefer the former.

Angular2 material dialog has issues - Did you add it to @NgModule.entryComponents?

This is happening because this is a dynamic component and you didn't add it to entryComponents under @NgModule.

Simply add it there:

  /* ----------------- */
  entryComponents: [ DialogResultExampleDialog ] // <---- Add it here

Look at how the Angular team talks about entryComponents:

entryComponents?: Array<Type<any>|any[]>

Specifies a list of components that should be compiled when this module is defined. For each component listed here, Angular will create a ComponentFactory and store it in the ComponentFactoryResolver.

Also, this is the list of the methods on @NgModule including entryComponents...

As you can see, all of them are optional (look at the question marks), including entryComponents which accept an array of components:

  providers?: Provider[]
  declarations?: Array<Type<any>|any[]>
  imports?: Array<Type<any>|ModuleWithProviders|any[]>
  exports?: Array<Type<any>|any[]>
  entryComponents?: Array<Type<any>|any[]>
  bootstrap?: Array<Type<any>|any[]>
  schemas?: Array<SchemaMetadata|any[]>
  id?: string

How to start up spring-boot application via command line?

1.Run Spring Boot app with java -jar command

To run your Spring Boot app from a command line in a Terminal window you can use java -jar command. This is provided your Spring Boot app was packaged as an executable jar file.

java -jar target/app-0.0.1-SNAPSHOT.jar

2.Run Spring Boot app using Maven

You can also use Maven plugin to run your Spring Boot app. Use the below command to run your Spring Boot app with Maven plugin:

mvn spring-boot:run

3.Run Spring Boot App with Gradle

And if you use Gradle you can run the Spring Boot app with the following command:

gradle bootRun

Checking if a string is empty or null in Java

This way you check if the string is not null and not empty, also considering the empty spaces:

boolean isEmpty = str == null || str.trim().length() == 0;
if (isEmpty) {
    // handle the validation

How do I perform an insert and return inserted identity with Dapper?

There is a great library to make your life easier Dapper.Contrib.Extensions. After including this you can just write:

public int Add(Transaction transaction)
        using (IDbConnection db = Connection)
                return (int)db.Insert(transaction);

How to get IP address of running docker container

while read ctr;do
    sudo docker inspect --format "$ctr "'{{.Name}}{{ .NetworkSettings.IPAddress }}' $ctr
done < <(docker ps -a --filter status=running --format '{{.ID}}')

How to detect a textbox's content has changed

Use the onchange event in HTML/standard JavaScript.

In jQuery that is the change() event. For example:

$('element').change(function() { // do something } );


After reading some comments, what about:

$(function() {
    var content = $('#myContent').val();

    $('#myContent').keyup(function() { 
        if ($('#myContent').val() != content) {
            content = $('#myContent').val();
            alert('Content has been changed');

How to get the current date and time of your timezone in Java?

Check this may be helpful. Works fine for me. Code also covered daylight savings

    TimeZone tz = TimeZone.getTimeZone("Asia/Shanghai");
    Calendar cal = Calendar.getInstance();      
    // If needed in hours rather than milliseconds
    int LocalOffSethrs = (int) ((cal.getTimeZone().getRawOffset()) *(2.77777778 /10000000));        
    int ChinaOffSethrs = (int) ((tz.getRawOffset()) *(2.77777778 /10000000));       
    int dts = cal.getTimeZone().getDSTSavings();
    System.out.println("Local Time Zone : " + cal.getTimeZone().getDisplayName());
    System.out.println("Local Day Light Time Saving : " + dts);
    System.out.println("China Time : " + tz.getRawOffset());
    System.out.println("Local Offset Time from GMT: " + LocalOffSethrs);
    System.out.println("China Offset Time from GMT: " + ChinaOffSethrs);    
    // Adjust to GMT
    // Adjust to Daylight Savings
    cal.add(Calendar.MILLISECOND, - cal.getTimeZone().getDSTSavings());
    // Adjust to Offset
    cal.add(Calendar.MILLISECOND, tz.getRawOffset());       
    Date dt = new Date(cal.getTimeInMillis());              
    System.out.println("After adjusting offset Acctual China Time :" + dt); 

Difference between onStart() and onResume()


  1. Called after onCreate(Bundle) or after onRestart() followed by onResume().
  2. you can register a BroadcastReceiver in onStart() to monitor changes that impact your UI, You have to unregister it in onStop()
  3. Derived classes must call through to the super class's implementation of this method. If they do not, an exception will be thrown.


  1. Called after onRestoreInstanceState(Bundle), onRestart(), or onPause()
  2. Begin animations, open exclusive-access devices (such as the camera)

onStart() normally dispatch work to a background thread, whose return values are:

  • START_STICKY to automatically restart if killed, to keep it active.

  • START_REDELIVER_INTENT for auto restart and retry if the service was killed before stopSelf().

onResume() is called by the OS after the device goes to sleep or after an Alert or other partial-screen child activity leaves a portion of the previous window visible so a method is need to re-initialize fields (within a try structure with a catch of exceptions). Such a situation does not cause onStop() to be invoked when the child closes.

onResume() is called without onStart() when the activity resumes from the background

For More details you can visits Android_activity_lifecycle_gotcha And Activity Lifecycle

How to export data from Excel spreadsheet to Sql Server 2008 table

In SQL Server 2016 the wizard is a separate app. (Important: Excel wizard is only available in the 32-bit version of the wizard!). Use the MSDN page for instructions:

On the Start menu, point to All Programs, point toMicrosoft SQL Server , and then click Import and Export Data.
In SQL Server Data Tools (SSDT), right-click the SSIS Packages folder, and then click SSIS Import and Export Wizard.
In SQL Server Data Tools (SSDT), on the Project menu, click SSIS Import and Export Wizard.
In SQL Server Management Studio, connect to the Database Engine server type, expand Databases, right-click a database, point to Tasks, and then click Import Data or Export data.
In a command prompt window, run DTSWizard.exe, located in C:\Program Files\Microsoft SQL Server\100\DTS\Binn.

After that it should be pretty much the same (possibly with minor variations in the UI) as in @marc_s's answer.

PHP - Session destroy after closing browser

There are different ways to do this, but the server can't detect when de browser gets closed so destroying it then is hard.

  • timeout session.

Either create a new session with the current time or add a time variable to the current session. and then check it when you start up or perform an action to see if the session has to be removed.

$_SESSION["timeout"] = time();
//if 100 seconds have passed since creating session delete it.
if(time() - $_SESSION["timeout"] > 100){ 
  • ajax

Make javascript perform an ajax call that will delete the session, with onbeforeunload() a javascript function that calls a final action when the user leaves the page. For some reason this doesnt always work though.

  • delete it on startup.

If you always want the user to see the login page on startup after the page has been closed you can just delete the session on startup.

<? php

and there probably are some more.

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '''')' at line 2

I was getting the same error when I used this code to update the record:

@mysqli_query($dbc,$query or die()))

After removing or die, it started working properly.

How to draw a filled circle in Java?

public void paintComponent(Graphics g) {
   Graphics2D g2d = (Graphics2D)g;
   // Assume x, y, and diameter are instance variables.
   Ellipse2D.Double circle = new Ellipse2D.Double(x, y, diameter, diameter);

Here are some docs about paintComponent (link).

You should override that method in your JPanel and do something similar to the code snippet above.

In your ActionListener you should specify x, y, diameter and call repaint().

How to get JSON data from the URL (REST API) to UI using jQuery or plain JavaScript?

You can use native JS so you don't have to rely on external libraries.

(I will use some ES2015 syntax, a.k.a ES6, modern javascript) What is ES2015?

    .then(response => response.json())
    .then(data => {
        // Do what you want with your data

You can also capture errors if any:

    .then(response => response.json())
    .then(data => {
        // Do what you want with your data
    .catch(err => {
        console.error('An error ocurred', err);

By default it uses GET and you don't have to specify headers, but you can do all that if you want. For further reference: Fetch API reference

How do I specify local .gem files in my Gemfile?

I found it easiest to run my own gem server using geminabox

See these simple instructions.

How to upload, display and save images using node.js and express

First of all, you should make an HTML form containing a file input element. You also need to set the form's enctype attribute to multipart/form-data:

<form method="post" enctype="multipart/form-data" action="/upload">
    <input type="file" name="file">
    <input type="submit" value="Submit">

Assuming the form is defined in index.html stored in a directory named public relative to where your script is located, you can serve it this way:

const http = require("http");
const path = require("path");
const fs = require("fs");

const express = require("express");

const app = express();
const httpServer = http.createServer(app);

const PORT = process.env.PORT || 3000;

httpServer.listen(PORT, () => {
  console.log(`Server is listening on port ${PORT}`);

// put the HTML file containing your form in a directory named "public" (relative to where this script is located)
app.get("/", express.static(path.join(__dirname, "./public")));

Once that's done, users will be able to upload files to your server via that form. But to reassemble the uploaded file in your application, you'll need to parse the request body (as multipart form data).

In Express 3.x you could use express.bodyParser middleware to handle multipart forms but as of Express 4.x, there's no body parser bundled with the framework. Luckily, you can choose from one of the many available multipart/form-data parsers out there. Here, I'll be using multer:

You need to define a route to handle form posts:

const multer = require("multer");

const handleError = (err, res) => {
    .end("Oops! Something went wrong!");

const upload = multer({
  dest: "/path/to/temporary/directory/to/store/uploaded/files"
  // you might also want to set some limits:
  upload.single("file" /* name attribute of <file> element in your form */),
  (req, res) => {
    const tempPath = req.file.path;
    const targetPath = path.join(__dirname, "./uploads/image.png");

    if (path.extname(req.file.originalname).toLowerCase() === ".png") {
      fs.rename(tempPath, targetPath, err => {
        if (err) return handleError(err, res);

          .end("File uploaded!");
    } else {
      fs.unlink(tempPath, err => {
        if (err) return handleError(err, res);

          .end("Only .png files are allowed!");

In the example above, .png files posted to /upload will be saved to uploaded directory relative to where the script is located.

In order to show the uploaded image, assuming you already have an HTML page containing an img element:

<img src="/image.png" />

you can define another route in your express app and use res.sendFile to serve the stored image:

app.get("/image.png", (req, res) => {
  res.sendFile(path.join(__dirname, "./uploads/image.png"));

Why does the Google Play store say my Android app is incompatible with my own device?

In Android some permissions <uses-permission> will imply <uses-feature> requirements to the app.

For example <uses-permission android:name="android.permission.BLUETOOTH" />
Will imply <uses-feature android:name="android.hardware.bluetooth"/>

You can check the whole list here

How to find out which JavaScript events fired?

Just thought I'd add that you can do this in Chrome as well:

Ctrl + Shift + I (Developer Tools) > Sources> Event Listener Breakpoints (on the right).

You can also view all events that have already been attached by simply right clicking on the element and then browsing its properties (the panel on the right).

For example:

  • Right click on the upvote button to the left
  • Select inspect element
  • Collapse the styles section (section on the far right - double chevron)
  • Expand the event listeners option
  • Now you can see the events bound to the upvote
  • Not sure if it's quite as powerful as the firebug option, but has been enough for most of my stuff.

    Another option that is a bit different but surprisingly awesome is Visual Event:

    It highlights all of the elements on a page that have been bound and has popovers showing the functions that are called. Pretty nifty for a bookmark! There's a Chrome plugin as well if that's more your thing - not sure about other browsers.

    AnonymousAndrew has also pointed out monitorEvents(window); here

    What's the difference between Instant and LocalDateTime?

    You are wrong about LocalDateTime: it does not store any time-zone information and it has nanosecond precision. Quoting the Javadoc (emphasis mine):

    A date-time without a time-zone in the ISO-8601 calendar system, such as 2007-12-03T10:15:30.

    LocalDateTime is an immutable date-time object that represents a date-time, often viewed as year-month-day-hour-minute-second. Other date and time fields, such as day-of-year, day-of-week and week-of-year, can also be accessed. Time is represented to nanosecond precision. For example, the value "2nd October 2007 at 13:45.30.123456789" can be stored in a LocalDateTime.

    The difference between the two is that Instant represents an offset from the Epoch (01-01-1970) and, as such, represents a particular instant on the time-line. Two Instant objects created at the same moment in two different places of the Earth will have exactly the same value.

    Use a.any() or a.all()

    You comment:

    valeur is a vector equal to [ 0. 1. 2. 3.] I am interested in each single term. For the part below 0.6, then return "this works"....

    If you are interested in each term, then write the code so it deals with each. For example.

    for b in valeur<=0.6:
        if b:
            print ("this works")
            print ("valeur is too high")

    This will write 2 lines.

    The error is produced by numpy code when you try to use it a context that expects a single, scalar, value. if b:... can only do one thing. It does not, by itself, iterate through the elements of b doing a different thing for each.

    You could also cast that iteration as list comprehension, e.g.

    ['yes' if b else 'no' for b in np.array([True, False, True])]

    AppFabric installation failed because installer MSI returned with error code : 1603

    I had the same problem today. I've found this link, where you can try 3 solutions. First solution helped for me.

    Microsoft ANSWER for this issue

    Python find elements in one list that are not in the other

    list_1=["a", "b", "c", "d", "e"]
    list_2=["a", "f", "c", "m"]
    for i in list_2:
        if i not in list_1:


    ['f', 'm']

    Setting device orientation in Swift iOS

    Above code might not be working due to possibility if your view controller belongs to a navigation controller. If yes then it has to obey the rules of the navigation controller even if it has different orientation rules itself. A better approach would be to let the view controller decide for itself and the navigation controller will use the decision of the top most view controller.

    We can support both locking to current orientation and autorotating to lock on a specific orientation with this generic extension on UINavigationController: -:

    extension UINavigationController {
                public override func shouldAutorotate() -> Bool {
                    return visibleViewController.shouldAutorotate()
            public override func supportedInterfaceOrientations() -> UIInterfaceOrientationMask {
                return (visibleViewController?.supportedInterfaceOrientations())!

    Now inside your view controller we can

    class ViewController: UIViewController {
        // MARK: Autoroate configuration
        override func shouldAutorotate() -> Bool {
            if (UIDevice.currentDevice().orientation == UIDeviceOrientation.Portrait ||
                UIDevice.currentDevice().orientation == UIDeviceOrientation.PortraitUpsideDown ||
                UIDevice.currentDevice().orientation == UIDeviceOrientation.Unknown) {
                    return true
            else {
                return false
        override func supportedInterfaceOrientations() -> Int {
            return Int(UIInterfaceOrientationMask.Portrait.rawValue) | Int(UIInterfaceOrientationMask.PortraitUpsideDown.rawValue)

    Hope it helps. Thanks

    Simple parse JSON from URL on Android and display in listview

    You could use AsyncTask, you'll have to customize to fit your needs, but something like the following

    Async task has three primary methods:

    1. onPreExecute() - most commonly used for setting up and starting a progress dialog

    2. doInBackground() - Makes connections and receives responses from the server (Do NOT try to assign response values to GUI elements, this is a common mistake, that cannot be done in a background thread).

    3. onPostExecute() - Here we are out of the background thread, so we can do user interface manipulation with the response data, or simply assign the response to specific variable types.

    First we will start the class, initialize a String to hold the results outside of the methods but inside the class, then run the onPreExecute() method setting up a simple progress dialog.

    class MyAsyncTask extends AsyncTask<String, String, Void> {
        private ProgressDialog progressDialog = new ProgressDialog(MainActivity.this);
        InputStream inputStream = null;
        String result = ""; 
        protected void onPreExecute() {
            progressDialog.setMessage("Downloading your data...");
            progressDialog.setOnCancelListener(new OnCancelListener() {
                public void onCancel(DialogInterface arg0) {

    Then we need to set up the connection and how we want to handle the response:

        protected Void doInBackground(String... params) {
            String url_select = "";
            ArrayList<NameValuePair> param = new ArrayList<NameValuePair>();
            try {
                // Set up HTTP post
                // HttpClient is more then less deprecated. Need to change to URLConnection
                HttpClient httpClient = new DefaultHttpClient();
                HttpPost httpPost = new HttpPost(url_select);
                httpPost.setEntity(new UrlEncodedFormEntity(param));
                HttpResponse httpResponse = httpClient.execute(httpPost);
                HttpEntity httpEntity = httpResponse.getEntity();
                // Read content & Log
                inputStream = httpEntity.getContent();
            } catch (UnsupportedEncodingException e1) {
                Log.e("UnsupportedEncodingException", e1.toString());
            } catch (ClientProtocolException e2) {
                Log.e("ClientProtocolException", e2.toString());
            } catch (IllegalStateException e3) {
                Log.e("IllegalStateException", e3.toString());
            } catch (IOException e4) {
                Log.e("IOException", e4.toString());
            // Convert response to string using String Builder
            try {
                BufferedReader bReader = new BufferedReader(new InputStreamReader(inputStream, "utf-8"), 8);
                StringBuilder sBuilder = new StringBuilder();
                String line = null;
                while ((line = bReader.readLine()) != null) {
                    sBuilder.append(line + "\n");
                result = sBuilder.toString();
            } catch (Exception e) {
                Log.e("StringBuilding & BufferedReader", "Error converting result " + e.toString());
        } // protected Void doInBackground(String... params)

    Lastly, here we will parse the return, in this example it was a JSON Array and then dismiss the dialog:

        protected void onPostExecute(Void v) {
            //parse JSON data
            try {
                JSONArray jArray = new JSONArray(result);    
                for(i=0; i < jArray.length(); i++) {
                    JSONObject jObject = jArray.getJSONObject(i);
                    String name = jObject.getString("name");
                    String tab1_text = jObject.getString("tab1_text");
                    int active = jObject.getInt("active");
                } // End Loop
            } catch (JSONException e) {
                Log.e("JSONException", "Error: " + e.toString());
            } // catch (JSONException e)
        } // protected void onPostExecute(Void v)
    } //class MyAsyncTask extends AsyncTask<String, String, Void>

    Linear Layout and weight in Android

    You have to write like this its Working for me

                android:layout_weight="1" />
                android:text="Not this time"
                android:layout_weight="1" />

    PHP string concatenation

    while ($personCount < 10) {
        $result.= $personCount . "person ";
        echo $result;

    redistributable offline .NET Framework 3.5 installer for Windows 8

    Try this command:

    Dism.exe /online /enable-feature /featurename:NetFX3 /Source:I:\Sources\sxs /LimitAccess

    I: partition of your Windows DVD.

    How to use BOOLEAN type in SELECT statement

    You can definitely get Boolean value from a SELECT query, you just can't use a Boolean data-type.

    You can represent a Boolean with 1/0.

    CASE WHEN (10 > 0) THEN 1  ELSE 0 END (It can be used in SELECT QUERY)

    Returns, 1 (in Hibernate/Mybatis/etc 1 is true). Otherwise, you can get printable Boolean values from a SELECT.


    This returns the string 'true'.

    How do I add a bullet symbol in TextView?

    Another best way to add bullet in any text view is stated below two steps:

    First, create a drawable

    <?xml version="1.0" encoding="utf-8"?>
        <!--set color of the bullet-->
           android:color="#666666"/> //set color of bullet
        <!--set size of the bullet-->

    Then add this drawable in textview and set its pedding by using below properties


    Getting file size in Python?

    Use os.path.getsize(path) which will

    Return the size, in bytes, of path. Raise OSError if the file does not exist or is inaccessible.

    import os

    Or use os.stat(path).st_size

    import os

    Or use Path(path).stat().st_size (Python 3.4+)

    from pathlib import Path

    Using Ajax.BeginForm with ASP.NET MVC 3 Razor

    Darin Dimitrov's solution worked for me with one exception. When I submitted the partial view with (intentional) validation errors, I ended up with duplicate forms being returned in the dialog:

    enter image description here

    To fix this I had to wrap the Html.BeginForm in a div:

    <div id="myForm">
        @using (Html.BeginForm("CreateDialog", "SupportClass1", FormMethod.Post, new { @class = "form-horizontal" }))
            //form contents

    When the form was submitted, I cleared the div in the success function and output the validated form:

        $('form').submit(function () {
            if ($(this).valid()) {
                    url: this.action,
                    type: this.method,
                    data: $(this).serialize(),
                    success: function (result) {
            return false;

    Insert entire DataTable into database at once instead of row by row?

    I discovered SqlBulkCopy is an easy way to do this, and does not require a stored procedure to be written in SQL Server.

    Here is an example of how I implemented it:

    // take note of SqlBulkCopyOptions.KeepIdentity , you may or may not want to use this for your situation.  
    using (var bulkCopy = new SqlBulkCopy(_connection.ConnectionString, SqlBulkCopyOptions.KeepIdentity))
          // my DataTable column names match my SQL Column names, so I simply made this loop. However if your column names don't match, just pass in which datatable name matches the SQL column name in Column Mappings
          foreach (DataColumn col in table.Columns)
              bulkCopy.ColumnMappings.Add(col.ColumnName, col.ColumnName);
          bulkCopy.BulkCopyTimeout = 600;
          bulkCopy.DestinationTableName = destinationTableName;

    Import local function from a module housed in another directory with relative imports in Jupyter Notebook using Python 3

    I have found that python-dotenv helps solve this issue pretty effectively. Your project structure ends up changing slightly, but the code in your notebook is a bit simpler and consistent across notebooks.

    For your project, do a little install.

    pipenv install python-dotenv

    Then, project changes to:

    +-- .env (this can be empty)
    +-- ipynb
    ¦   +-- 20170609-Examine_Database_Requirements.ipynb
    ¦   +-- 20170609-Initial_Database_Connection.ipynb
    +-- lib

    And finally, your import changes to:

    import os
    import sys
    from dotenv import find_dotenv

    A +1 for this package is that your notebooks can be several directories deep. python-dotenv will find the closest one in a parent directory and use it. A +2 for this approach is that jupyter will load environment variables from the .env file on startup. Double whammy.

    How to set a header in an HTTP response?

    First of all you have to understand the nature of


    It is giving the client (browser) 302 http code response with an URL. The browser then makes a separate GET request on that URL. And that request has no knowledge of headers in the first one.

    So sendRedirect won't work if you need to pass a header from Servlet A to Servlet B.

    If you want this code to work - use RequestDispatcher in Servlet A (instead of sendRedirect). Also, it is always better to use relative path.

    public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException
        String userName=request.getParameter("userName");
        String newUrl = "ServletB";
        response.addHeader("REMOTE_USER", userName);
        RequestDispatcher view = request.getRequestDispatcher(newUrl);
        view.forward(request, response);


    public void doPost(HttpServletRequest request, HttpServletResponse response)
        String sss = response.getHeader("REMOTE_USER");

    PHP save image file

    Note: you should use the accepted answer if possible. It's better than mine.

    It's quite easy with the GD library.

    It's built in usually, you probably have it (use phpinfo() to check)

    $image = imagecreatefromjpeg("");
    imagejpeg($image, "folder/file.jpg");

    The above answer is better (faster) for most situations, but with GD you can also modify it in some form (cropping for example).

    $image = imagecreatefromjpeg("");
    imagecopy($image, $image, 0, 140, 0, 0, imagesx($image), imagesy($image));
    imagejpeg($image, "folder/file.jpg");

    This only works if allow_url_fopen is true (it is by default)

    Trying to get Laravel 5 email to work

    My opinion after making changes on your .env files restart your server and serve the app again. Just to be sure of the actual error. The php artisan clear and cache afterwards works pretty fine.

    How to upload a project to Github

    I think the easiest thing for you to do would be to install the git plugin for eclipse, works more or less the same as eclipse CVS and SVN plugins:


    Method to Add new or update existing item in Dictionary

    I know it is not Dictionary<TKey, TValue> class, however you can avoid KeyNotFoundException while incrementing a value like:

    dictionary[key]++; // throws `KeyNotFoundException` if there is no such key  

    by using ConcurrentDictionary<TKey, TValue> and its really nice method AddOrUpdate()..

    Let me show an example:

    var str = "Hellooo!!!";
    var characters = new ConcurrentDictionary<char, int>();
    foreach (var ch in str)
        characters.AddOrUpdate(ch, 1, (k, v) => v + 1);

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

    UseParNewGC usually knowns as "parallel young generation collector" is same in all ways as the parallel garbage collector (-XX:+UseParallelGC), except that its more sophiscated and effiecient. Also it can be used with a "concurrent low pause collector".

    See Java GC FAQ, question 22 for more information.

    Note that there are some known bugs with UseParNewGC

    Windows cannot find 'http:/.'. Make sure you typed the name correctly, and then try again

    I have installed Oracle 11g XE on Windows 10 OS. It's installed successfully on my PC but it's showing error which is :
    "windows cannot find 'http //"

    Just follow some steps

    In SQL command prompt just type

    sql> net start OracleServiceXe after start the Oracle server.

    Type SQL> Connect SYS / System as SYSDBA / SYSOPERA

    Then type your password which is given by you at the time of installation of Oracle 11g XE. (Press enter).

    but You can get login on oracle through this

    Note: ( My suggestion to you just type port after[PortNumber]/apex/f?p=4950 )

    I got loged in successfully.

    jQuery: how to change title of document during .ready()?

    <script type="text/javascript">
    $(document).ready(function() {
        $(this).attr("title", "sometitle");