Programs & Examples On #Documentpaginator

Precision String Format Specifier In Swift

Why make it so complicated? You can use this instead:

import UIKit

let PI = 3.14159265359

round( PI ) // 3.0 rounded to the nearest decimal
round( PI * 100 ) / 100 //3.14 rounded to the nearest hundredth
round( PI * 1000 ) / 1000 // 3.142 rounded to the nearest thousandth

See it work in Playground.

PS: Solution from:

Is there "\n" equivalent in VBscript?

I think it's vbcrlf.

replace(s, vbcrlf, "<br />")

C++ -- expected primary-expression before ' '

You don't need "string" in your call to wordLengthFunction().

int wordLength = wordLengthFunction(string word);

should be

int wordLength = wordLengthFunction(word);

Pass correct "this" context to setTimeout callback?

There are ready-made shortcuts (syntactic sugar) to the function wrapper @CMS answered with. (Below assuming that the context you want is this.tip.)

ECMAScript 2015 (all common browsers and smartphones, Node.js 5.0.0+)

For virtually all javascript development (in 2020) you can use fat arrow functions, which are part of the ECMAScript 2015 (Harmony/ES6/ES2015) specification.

An arrow function expression (also known as fat arrow function) has a shorter syntax compared to function expressions and lexically binds the this value [...].

(param1, param2, => { statements }

In your case, try this:

if (this.options.destroyOnHide) {
    setTimeout(() => { this.tip.destroy(); }, 1000);

ECMAScript 5 (older browsers and smartphones, Node.js) and Prototype.js

If you target browser compatible with ECMA-262, 5th edition (ECMAScript 5) or Node.js, which (in 2020) means all common browsers as well as older browsers, you could use Function.prototype.bind. You can optionally pass any function arguments to create partial functions.

fun.bind(thisArg[, arg1[, arg2[, ...]]])

Again, in your case, try this:

if (this.options.destroyOnHide) {
    setTimeout(this.tip.destroy.bind(this.tip), 1000);

The same functionality has also been implemented in Prototype (any other libraries?).

Function.prototype.bind can be implemented like this if you want custom backwards compatibility (but please observe the notes).


If you are already using jQuery 1.4+, there's a ready-made function for explicitly setting the this context of a function.

jQuery.proxy(): Takes a function and returns a new one that will always have a particular context.

$.proxy(function, context[, additionalArguments])

In your case, try this:

if (this.options.destroyOnHide) {
    setTimeout($.proxy(this.tip.destroy, this.tip), 1000);

Underscore.js, lodash

It's available in Underscore.js, as well as lodash, as _.bind(...)1,2

bind Bind a function to an object, meaning that whenever the function is called, the value of this will be the object. Optionally, bind arguments to the function to pre-fill them, also known as partial application.

_.bind(function, object, [*arguments])

In your case, try this:

if (this.options.destroyOnHide) {
    setTimeout(_.bind(this.tip.destroy, this.tip), 1000);

Replacing instances of a character in a string

To replace a character at a specific index, the function is as follows:

def replace_char(s , n , c):
    s = s[0:n] + s[n:n+1].replace(s[n] , c) + s[n+1:]
    return s

where s is a string, n is index and c is a character.

Button Center CSS

Consider adding this to your CSS to resolve the problem:

button {
    margin: 0 auto;
    display: block;

How to completely remove borders from HTML table

In a bootstrap environment here is my solution:

    <table style="border-collapse: collapse; border: none;">
        <tr style="border: none;">
            <td style="border: none;">

IE prompts to open or save json result from server

Is above javascript code the one you're using in your web application ? If so - i would like to point few errors in it: firstly - it has an additional '{' sign in definition of 'success' callback function secondly - it has no ')' sign after definition of ajax callback. Valid code should look like:

        data: 'args',
        url: '@Url.Action("PostBack")',
        success: function (data, textStatus, jqXHR) {

try using above code - it gave me 'Yay' alert on all 3 IE versions ( 7,8,9 ).

Display special characters when using print statement

Do you merely want to print the string that way, or do you want that to be the internal representation of the string? If the latter, create it as a raw string by prefixing it with r: r"Hello\tWorld\nHello World".

>>> a = r"Hello\tWorld\nHello World"
>>> a # in the interpreter, this calls repr()
'Hello\\tWorld\\nHello World'
>>> print a
Hello\tWorld\nHello World

Also, \s is not an escape character, except in regular expressions, and then it still has a much different meaning than what you're using it for.

When to use EntityManager.find() vs EntityManager.getReference() with JPA

I usually use getReference method when i do not need to access database state (I mean getter method). Just to change state (I mean setter method). As you should know, getReference returns a proxy object which uses a powerful feature called automatic dirty checking. Suppose the following

public class Person {

    private String name;
    private Integer age;


public class PersonServiceImpl implements PersonService {

    public void changeAge(Integer personId, Integer newAge) {
        Person person = em.getReference(Person.class, personId);

        // person is a proxy


If i call find method, JPA provider, behind the scenes, will call



If i call getReference method, JPA provider, behind the scenes, will call


And you know why ???

When you call getReference, you will get a proxy object. Something like this one (JPA provider takes care of implementing this proxy)

public class PersonProxy {

    // JPA provider sets up this field when you call getReference
    private Integer personId;

    private String query = "UPDATE PERSON SET ";

    private boolean stateChanged = false;

    public void setAge(Integer newAge) {
        stateChanged = true;

        query += query + "AGE = " + newAge;


So before transaction commit, JPA provider will see stateChanged flag in order to update OR NOT person entity. If no rows is updated after update statement, JPA provider will throw EntityNotFoundException according to JPA specification.


MySQL: View with Subquery in the FROM Clause Limitation

It appears to be a known issue.

Many IN queries can be re-written as (left outer) joins and an IS (NOT) NULL of some sort. for example


can be re-written as




can be


Owl Carousel Won't Autoplay

add this


What properties can I use with

//Do it like---
function dragStart(this_,event) {
    var row=$(this_).attr('whatever');
    event.dataTransfer.setData("Text", row);

std::thread calling method of class

Not so hard:

#include <thread>

void Test::runMultiThread()
    std::thread t1(&Test::calculate, this,  0, 10);
    std::thread t2(&Test::calculate, this, 11, 20);

If the result of the computation is still needed, use a future instead:

#include <future>

void Test::runMultiThread()
     auto f1 = std::async(&Test::calculate, this,  0, 10);
     auto f2 = std::async(&Test::calculate, this, 11, 20);

     auto res1 = f1.get();
     auto res2 = f2.get();

Check if an array is empty or exists


( typeof(myArray) !== 'undefined' && Array.isArray(myArray) && myArray.length > 0 )

Lodash & Underscore

( _.isArray(myArray) && myArray.length > 0 )

Simplest way to restart service on a remote computer

I recommend the method given by doofledorfer.

If you really want to do it via a direct API call, then look at the OpenSCManager function. Below are sample functions to take a machine name and service, and stop or start them.

function ServiceStart(sMachine, sService : string) : boolean;  //start service, return TRUE if successful
var schm, schs : SC_Handle;
    ss         : TServiceStatus;
    psTemp     : PChar;
    dwChkP     : DWord;
  ss.dwCurrentState := 0;
  schm := OpenSCManager(PChar(sMachine),Nil,SC_MANAGER_CONNECT);  //connect to the service control manager

  if(schm > 0)then begin // if successful...
    schs := OpenService( schm,PChar(sService),SERVICE_START or SERVICE_QUERY_STATUS);    // open service handle, start and query status
    if(schs > 0)then begin     // if successful...
      psTemp := nil;
      if (StartService(schs,0,psTemp)) and (QueryServiceStatus(schs,ss)) then
        while(SERVICE_RUNNING <> ss.dwCurrentState)do begin
          dwChkP := ss.dwCheckPoint;  //dwCheckPoint contains a value incremented periodically to report progress of a long operation.  Store it.
          Sleep(ss.dwWaitHint);  //Sleep for recommended time before checking status again
          if(not QueryServiceStatus(schs,ss))then
            break;  //couldn't check status
          if(ss.dwCheckPoint < dwChkP)then
            Break;  //if QueryServiceStatus didn't work for some reason, avoid infinite loop
        end;  //while not running
    end;  //if able to get service handle
  end;  //if able to get svc mgr handle
  Result := SERVICE_RUNNING = ss.dwCurrentState;  //if we were able to start it, return true

function ServiceStop(sMachine, sService : string) : boolean;  //stop service, return TRUE if successful
var schm, schs : SC_Handle;
    ss         : TServiceStatus;
    dwChkP     : DWord;
  schm := OpenSCManager(PChar(sMachine),nil,SC_MANAGER_CONNECT);

  if(schm > 0)then begin
    schs := OpenService(schm,PChar(sService),SERVICE_STOP or SERVICE_QUERY_STATUS);
    if(schs > 0)then begin
      if (ControlService(schs,SERVICE_CONTROL_STOP,ss)) and (QueryServiceStatus(schs,ss)) then
        while(SERVICE_STOPPED <> ss.dwCurrentState) do begin
          dwChkP := ss.dwCheckPoint;
          if(not QueryServiceStatus(schs,ss))then

          if(ss.dwCheckPoint < dwChkP)then
        end;  //while
    end;  //if able to get svc handle
  end;  //if able to get svc mgr handle
  Result := SERVICE_STOPPED = ss.dwCurrentState;

Detect home button press in android

An option for your application would be to write a replacement Home Screen using the android.intent.category.HOME Intent. I believe this type of Intent you can see the home button.

More details:

Image inside div has extra space below the image

One can also nullify parent's line height:

#wrapper {
  line-height: 0;

All fixes:

How to dynamically add rows to a table in ASP.NET?

in addition to what Kirk said I want to tell you that just "playing around" won't help you to learn, and there is a lot of free and very good tutorials .
take a look on the official site tutorials and on 4GuysFromRolla site

Removing multiple files from a Git repo that have already been deleted from disk

git add -u

-u --update Only match against already tracked files in the index rather than the working tree. That means that it will never stage new files, but that it will stage modified new contents of tracked files and that it will remove files from the index if the corresponding files in the working tree have been removed.

If no is given, default to "."; in other words, update all tracked files in the current directory and its subdirectories.

docker unauthorized: authentication required - upon push with successful login

Make sure you have more slots for private images.

In my case I converted a user into an organization and it lost it's one free private image, so previous pushes that worked, no longer worked.

How I add Headers to http.get or in Typescript and angular 2?

You can define a Headers object with a dictionary of HTTP key/value pairs, and then pass it in as an argument to http.get() and like this:

const headerDict = {
  'Content-Type': 'application/json',
  'Accept': 'application/json',
  'Access-Control-Allow-Headers': 'Content-Type',

const requestOptions = {                                                                                                                                                                                 
  headers: new Headers(headerDict), 

return this.http.get(this.heroesUrl, requestOptions)

Or, if it's a POST request:

const data = JSON.stringify(heroData);
return, data, requestOptions);

Since Angular 7 and up you have to use HttpHeaders class instead of Headers:

const requestOptions = {                                                                                                                                                                                 
  headers: new HttpHeaders(headerDict), 

HTML 5 input type="number" element for floating point numbers on Chrome

Try <input type="number" step="0.01" /> if you are targeting 2 decimal places :-).

SQL Server: Difference between PARTITION BY and GROUP BY

-- CREATE A database called testDB

-- use testDB
USE [TestDB]

-- create Paints table
CREATE TABLE [dbo].[Paints](
    [Color] [varchar](50) NULL,
    [glossLevel] [varchar](50) NULL


-- Populate Table
insert into paints (color, glossLevel)
select 'red', 'eggshell'
select 'red', 'glossy'
select 'red', 'flat'
select 'blue', 'eggshell'
select 'blue', 'glossy'
select 'blue', 'flat'
select 'orange', 'glossy'
select 'orange', 'flat'
select 'orange', 'eggshell'
select 'green', 'eggshell'
select 'green', 'glossy'
select 'green', 'flat'
select 'black', 'eggshell'
select 'black', 'glossy'
select 'black', 'flat'
select 'purple', 'eggshell'
select 'purple', 'glossy'
select 'purple', 'flat'
select 'salmon', 'eggshell'
select 'salmon', 'glossy'
select 'salmon', 'flat'

/*   COMPARE 'GROUP BY' color to 'OVER (PARTITION BY Color)'  */

-- GROUP BY Color 
-- row quantity defined by group by
-- aggregate (count(*)) defined by group by
select count(*) from paints
group by color

-- row quantity defined by main query
-- aggregate defined by OVER-PARTITION BY
select color
, glossLevel
, count(*) OVER (Partition by color)
from paints

/* COMPARE 'GROUP BY' color, glossLevel to 'OVER (PARTITION BY Color, GlossLevel)'  */

-- GROUP BY Color, GlossLevel
-- row quantity defined by GROUP BY
-- aggregate (count(*)) defined by GROUP BY
select count(*) from paints
group by color, glossLevel

-- Partition by Color, GlossLevel
-- row quantity defined by main query
-- aggregate (count(*)) defined by OVER-PARTITION BY
select color
, glossLevel
, count(*) OVER (Partition by color, glossLevel)
from paints

List file names based on a filename pattern and file content?

grep LMN20113456 LMN2011*

or if you want to search recursively through subdirectories:

find . -type f -name 'LMN2011*' -exec grep LMN20113456 {} \;

Javascript Uncaught Reference error Function is not defined

If you are using Angular.js then functions imbedded into HTML, such as onclick="function()" or onchange="function()". They will not register. You need to make the change events in the javascript. Such as:

$('#exampleBtn').click(function() {

Counter in foreach loop in C#

Probably pointless, but...

foreach (var item in yourList.Select((Value, Index) => new { Value, Index }))
    Console.WriteLine("Value=" + item.Value + ", Index=" + item.Index);

What is the difference between exit and return?

I wrote two programs:

int main(){return 0;}


#include <stdlib.h>
int main(){exit(0)}

After executing gcc -S -O1. Here what I found watching at assembly (only important parts):

    movl    $0, %eax    /* setting return value */
    ret                 /* return from main */


    subq    $8, %rsp    /* reserving some space */
    movl    $0, %edi    /* setting return value */
    call    exit        /* calling exit function */
                        /* magic and machine specific wizardry after this call */

So my conclusion is: use return when you can, and exit() when you need.

How does one convert a HashMap to a List in Java?

If you only want it to iterate over your HashMap, no need for a list:

HashMap<Integer, String> map = new HashMap<Integer, String>();
map.put (1, "Mark");
map.put (2, "Tarryn");
for (String s : map.values()) {

Of course, if you want to modify your map structurally (i.e. more than only changing the value for an existing key) while iterating, then you better use the "copy to ArrayList" method, since otherwise you'll get a ConcurrentModificationException. Or export as an array:

HashMap<Integer, String> map = new HashMap<Integer, String>();
map.put (1, "Mark");
map.put (2, "Tarryn");
for (String s : map.values().toArray(new String[]{})) {

how to get bounding box for div element in jquery

using JQuery:

[myelement.offset().left, myelement.offset().top,  myelement.width(), myelement.height()]

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

I had the same error, because I was trying to manipulate session variables inside a custom Session class.

I had to pass the current context (system.web.httpcontext.current) into the class, and then everything worked out fine.


How to query GROUP BY Month in a Year

I would be inclined to include the year in the output. One way:

select to_char(DATE_CREATED, 'YYYY-MM'), sum(Num_of_Pictures)
from pictures_table
group by to_char(DATE_CREATED, 'YYYY-MM')
order by 1

Another way (more standard SQL):

select extract(year from date_created) as yr, extract(month from date_created) as mon,
from pictures_table
group by extract(year from date_created), extract(month from date_created)
order by yr, mon;

Remember the order by, since you presumably want these in order, and there is no guarantee about the order that rows are returned in after a group by.

Parsing json and searching through it

As json.loads simply returns a dict, you can use the operators that apply to dicts:

>>> jdata = json.load('{"uri": "http:", "foo", "bar"}')
>>> 'uri' in jdata       # Check if 'uri' is in jdata's keys
>>> jdata['uri']         # Will return the value belonging to the key 'uri'

Edit: to give an idea regarding how to loop through the data, consider the following example:

>>> import json
>>> jdata = json.loads(open ('bookmarks.json').read())
>>> for c in jdata['children'][0]['children']:
...     print 'Title: {}, URI: {}'.format(c.get('title', 'No title'),
                                          c.get('uri', 'No uri'))
Title: Recently Bookmarked, URI: place:folder=BOOKMARKS_MENU(...)
Title: Recent Tags, URI: place:sort=14&type=6&maxResults=10&queryType=1
Title: , URI: No uri
Title: Mozilla Firefox, URI: No uri

Inspecting the jdata data structure will allow you to navigate it as you wish. The pprint call you already have is a good starting point for this.

Edit2: Another attempt. This gets the file you mentioned in a list of dictionaries. With this, I think you should be able to adapt it to your needs.

>>> def build_structure(data, d=[]):
...     if 'children' in data:
...         for c in data['children']:
...             d.append({'title': c.get('title', 'No title'),
...                                      'uri': c.get('uri', None)})
...             build_structure(c, d)
...     return d
>>> pprint.pprint(build_structure(jdata))
[{'title': u'Bookmarks Menu', 'uri': None},
 {'title': u'Recently Bookmarked',
  'uri':   u'place:folder=BOOKMARKS_MENU&folder=UNFILED_BOOKMARKS&(...)'},
 {'title': u'Recent Tags',
  'uri':   u'place:sort=14&type=6&maxResults=10&queryType=1'},
 {'title': u'', 'uri': None},
 {'title': u'Mozilla Firefox', 'uri': None},
 {'title': u'Help and Tutorials',
  'uri':   u''},

To then "search through it for u'uri': u'http:'", do something like this:

for c in build_structure(jdata):
    if c['uri'].startswith('http:'):
        print 'Started with http'

How to make an image center (vertically & horizontally) inside a bigger div

Working in old browsers (IE >= 8)

Absolute position in combination with automatic margin permits to center an element horizontally and vertically. The element position could be based on a parent element position using relative positioning. View Result

img {
    position: absolute;
    margin: auto;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;

How to tell if a file is git tracked (by shell exit code)?


git ls-files --error-unmatch <file name>

will exit with 1 if file is not tracked

How do I get the path and name of the file that is currently executing?

You can use inspect.stack()

import inspect,os
inspect.stack()[0]  => (<frame object at 0x00AC2AC0>, 'g:\\Python\\Test\\', 15, '<module>', ['print inspect.stack()[0]\n'], 0)
os.path.abspath (inspect.stack()[0][1]) => 'g:\\Python\\Test\\'

Run two async tasks in parallel and collect results in .NET 4.5

While your Sleep method is async, Thread.Sleep is not. The whole idea of async is to reuse a single thread, not to start multiple threads. Because you've blocked using a synchronous call to Thread.Sleep, it's not going to work.

I'm assuming that Thread.Sleep is a simplification of what you actually want to do. Can your actual implementation be coded as async methods?

If you do need to run multiple synchronous blocking calls, look elsewhere I think!

how to create inline style with :before and :after

If you really need it inline, for example because you are loading some user-defined colors dynamically, you can always add a <style> element right before your content.

<style>#project-slide-1:before { color: #ff0000; }</style>
<div id="project-slide-1" class="project-slide"> ... </div>

Example use case with PHP and some (wordpress inspired) dummy functions:

<style>#project-slide-<?php the_ID() ?>:before { color: <?php the_field('color') ?>; }</style>
<div id="project-slide-<?php the_ID() ?>" class="project-slide"> ... </div>

Since HTML 5.2 it is valid to place style elements inside the body, although it is still recommend to place style elements in the head.


Get immediate first child element

Both these will give you the first child node:

console.log(parentElement.firstChild); // or

If you need the first child that is an element node then use:



Ah, I see your problem now; parentElement is an array.

If you know that getElementsByClassName will only return one result, which it seems you do, you should use [0] to dearray (yes, I made that word up) the element:

var parentElement = document.getElementsByClassName("uniqueClassName")[0]; cannot open shared object file: No such file or directory

For Fedora use:

yum install libstdc++44.i686

You can find out which versions are supported by running:

yum list all | grep libstdc | grep i686

Play audio with Python

Your best bet is probably to use pygame/SDL. It's an external library, but it has great support across platforms.


You can find more specific documentation about the audio mixer support in the documentation

Touch move getting stuck Ignored attempt to cancel a touchmove

Please remove e.preventDefault(), because event.cancelable of touchmove is false. So you can't call this method.

Test credit card numbers for use with PayPal sandbox

In case anyone else comes across this in a search for an answer...

The test numbers listed in various places no longer work in the Sandbox. PayPal have the same checks in place now so that a card cannot be linked to more than one account.

Go here and get a number generated. Use any expiry date and CVV

It's worked every time for me so far...

How can I check the syntax of Python script without executing it?

You can check the syntax by compiling it:

python -m py_compile

SSLHandshakeException: No subject alternative names present

Thanks,Bruno for giving me heads up on Common Name and Subject Alternative Name. As we figured out certificate was generated with CN with DNS name of network and asked for regeneration of new certificate with Subject Alternative Name entry i.e. san=ip: which is the actual solution.

But, we managed to find out a workaround with which we can able to run on development phase. Just add a static block in the class from which we are making ssl connection.

static {
    HttpsURLConnection.setDefaultHostnameVerifier(new HostnameVerifier()
            public boolean verify(String hostname, SSLSession session)
                // ip address of the service URL(like.
                if (hostname.equals(""))
                    return true;
                return false;

If you happen to be using Java 8, there is a much slicker way of achieving the same result:

static {
    HttpsURLConnection.setDefaultHostnameVerifier((hostname, session) -> hostname.equals(""));


Have you verified that there is in fact a row where Staff_Id = @PersonID? What you've posted works fine in a test script, assuming the row exists. If you comment out the insert statement, then the error is raised.

set nocount on

create table Timesheet_Hours (Staff_Id int, BookedHours int, Posted_Flag bit)

insert into Timesheet_Hours (Staff_Id, BookedHours, Posted_Flag) values (1, 5.5, 0)

declare @PersonID int
set @PersonID = 1

    SELECT 1    
    FROM Timesheet_Hours    
    WHERE Posted_Flag = 1    
        AND Staff_Id = @PersonID    
        RAISERROR('Timesheets have already been posted!', 16, 1)
        SELECT 1
        FROM Timesheet_Hours
        WHERE Staff_Id = @PersonID
            RAISERROR('Default list has not been loaded!', 16, 1)
            ROLLBACK TRAN
        print 'No problems here'

drop table Timesheet_Hours

Can't find bundle for base name /Bundle, locale en_US

I was able to resolve the issue, the resource was in my project directories but when the junit utility tries to load it, it was returning an error of MissingResourceException. And the reason was the resource was in the not on the classpath of the test class package so when I added the cfg/ folder to my classpath path entry in eclipse and set the output directory in the build conf to the same class package the issue was resolved.

When you try this approach just make sure, the classpath conf file shows the classpath entry of the resource directory (eg. cfg/)

Find a pair of elements from an array whose sum equals a given number

There are 3 approaches to this solution:

Let the sum be T and n be the size of array

Approach 1:
The naive way to do this would be to check all combinations (n choose 2). This exhaustive search is O(n2).

Approach 2: 
 A better way would be to sort the array. This takes O(n log n)
Then for each x in array A, use binary search to look for T-x. This will take O(nlogn).
So, overall search is  O(n log n)

Approach 3 :
The best way would be to insert every element into a hash table (without sorting). This takes O(n) as constant time insertion.
Then for every x, we can just look up its complement, T-x, which is O(1).
Overall the run time of this approach is O(n).

You can refer more here.Thanks.

How to force deletion of a python object?

The way to close resources are context managers, aka the with statement:

class Foo(object):

  def __init__(self): = None

  def __enter__(self):
    if != 'open':
      print 'opening the bar' = 'open'
    return self # this is bound to the `as` part

  def close(self):
    if != 'closed':
      print 'closing the bar' = 'close'

  def __exit__(self, *err):

if __name__ == '__main__':
  with Foo() as foo:
    print foo,


opening the bar
<__main__.Foo object at 0x17079d0> open
closing the bar

2) Python's objects get deleted when their reference count is 0. In your example the del foo removes the last reference so __del__ is called instantly. The GC has no part in this.

class Foo(object):

    def __del__(self):
        print "deling", self

if __name__ == '__main__':
    import gc
    gc.disable() # no gc
    f = Foo()
    print "before"
    del f # f gets deleted right away
    print "after"


deling <__main__.Foo object at 0xc49690>

The gc has nothing to do with deleting your and most other objects. It's there to clean up when simple reference counting does not work, because of self-references or circular references:

class Foo(object):
    def __init__(self, other=None):
        # make a circular reference = other
        if other is not None:
   = self

    def __del__(self):
        print "deling", self

if __name__ == '__main__':
    import gc
    f = Foo(Foo())
    print "before"
    del f # nothing gets deleted here
    print "after"
    print gc.garbage # The GC knows the two Foos are garbage, but won't delete
                     # them because they have a __del__ method
    print "after gc"
    # break up the cycle and delete the reference from gc.garbage
    del gc.garbage[0].link, gc.garbage[:]
    print "done"


[<__main__.Foo object at 0x22ed8d0>, <__main__.Foo object at 0x22ed950>]
after gc
deling <__main__.Foo object at 0x22ed950>
deling <__main__.Foo object at 0x22ed8d0>

3) Lets see:

class Foo(object):
    def __init__(self):

        raise Exception

    def __del__(self):
        print "deling", self

if __name__ == '__main__':
    f = Foo()


Traceback (most recent call last):
  File "", line 10, in <module>
    f = Foo()
  File "", line 4, in __init__
    raise Exception
deling <__main__.Foo object at 0xa3a910>

Objects are created with __new__ then passed to __init__ as self. After a exception in __init__, the object will typically not have a name (ie the f = part isn't run) so their ref count is 0. This means that the object is deleted normally and __del__ is called.

Android - setOnClickListener vs OnClickListener vs View.OnClickListener

Imagine that we have 3 buttons for example

public class MainActivity extends ActionBarActivity {

    protected void onCreate(Bundle savedInstanceState) {


        // Capture our button from layout
        Button button = (Button)findViewById(;
        Button button2 = (Button)findViewById(;
        Button button3 = (Button)findViewById(;
        // Register the onClick listener with the implementation above


    // Create an anonymous implementation of OnClickListener
    private View.OnClickListener mCorkyListener = new View.OnClickListener() {
        public void onClick(View v) {
            // do something when the button is clicked 
            // Yes we will handle click here but which button clicked??? We don't know



So what we will do?

public class MainActivity extends ActionBarActivity {

    protected void onCreate(Bundle savedInstanceState) {


        // Capture our button from layout
        Button button = (Button)findViewById(;
        Button button2 = (Button)findViewById(;
        Button button3 = (Button)findViewById(;
        // Register the onClick listener with the implementation above


    // Create an anonymous implementation of OnClickListener
    private View.OnClickListener mCorkyListener = new View.OnClickListener() {
        public void onClick(View v) {
            // do something when the button is clicked
            // Yes we will handle click here but which button clicked??? We don't know

            // So we will make
            switch (v.getId() /*to get clicked view id**/) {

                    // do something when the corky is clicked


                    // do something when the corky2 is clicked


                    // do something when the corky3 is clicked



Or we can do this:

public class MainActivity extends ActionBarActivity {

    protected void onCreate(Bundle savedInstanceState) {


        // Capture our button from layout
        Button button = (Button)findViewById(;
        Button button2 = (Button)findViewById(;
        Button button3 = (Button)findViewById(;
        // Register the onClick listener with the implementation above
        button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                // do something when the corky is clicked
        button2.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                // do something when the corky2 is clicked
        button3.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                // do something when the corky3 is clicked



Or we can implement View.OnClickListener and i think it's the best way:

public class MainActivity extends ActionBarActivity implements View.OnClickListener {

    protected void onCreate(Bundle savedInstanceState) {


        // Capture our button from layout
        Button button = (Button)findViewById(;
        Button button2 = (Button)findViewById(;
        Button button3 = (Button)findViewById(;
        // Register the onClick listener with the implementation above


    public void onClick(View v) {
        // do something when the button is clicked
        // Yes we will handle click here but which button clicked??? We don't know

        // So we will make
        switch (v.getId() /*to get clicked view id**/) {

                // do something when the corky is clicked


                // do something when the corky2 is clicked


                // do something when the corky3 is clicked


Finally there is no real differences here Just "Way better than the other"

Merging multiple PDFs using iTextSharp in

Using iTextSharp.dll

protected void Page_Load(object sender, EventArgs e)
    String[] files = @"C:\ENROLLDOCS\A1.pdf,C:\ENROLLDOCS\A2.pdf".Split(',');
    MergeFiles(@"C:\ENROLLDOCS\New1.pdf", files);
public void MergeFiles(string destinationFile, string[] sourceFiles)
    if (System.IO.File.Exists(destinationFile))

    string[] sSrcFile;
    sSrcFile = new string[2];

    string[] arr = new string[2];
    for (int i = 0; i <= sourceFiles.Length - 1; i++)
        if (sourceFiles[i] != null)
            if (sourceFiles[i].Trim() != "")
                arr[i] = sourceFiles[i].ToString();

    if (arr != null)
        sSrcFile = new string[2];

        for (int ic = 0; ic <= arr.Length - 1; ic++)
            sSrcFile[ic] = arr[ic].ToString();
        int f = 0;

        PdfReader reader = new PdfReader(sSrcFile[f]);
        int n = reader.NumberOfPages;
        Response.Write("There are " + n + " pages in the original file.");
        Document document = new Document(PageSize.A4);

        PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(destinationFile, FileMode.Create));

        PdfContentByte cb = writer.DirectContent;
        PdfImportedPage page;

        int rotation;
        while (f < sSrcFile.Length)
            int i = 0;
            while (i < n)

                page = writer.GetImportedPage(reader, i);

                rotation = reader.GetPageRotation(i);
                if (rotation == 90 || rotation == 270)
                    cb.AddTemplate(page, 0, -1f, 1f, 0, 0, reader.GetPageSizeWithRotation(i).Height);
                    cb.AddTemplate(page, 1f, 0, 0, 1f, 0, 0);
                Response.Write("\n Processed page " + i);

            if (f < sSrcFile.Length)
                reader = new PdfReader(sSrcFile[f]);
                n = reader.NumberOfPages;
                Response.Write("There are " + n + " pages in the original file.");
    catch (Exception e)


Border length smaller than div width?

You can use a linear gradient:

div {_x000D_
    background-image: linear-gradient(to right, #000 1px, rgba(255,255,255,0) 1px), linear-gradient(to left, #000 0.1rem, rgba(255,255,255,0) 1px);_x000D_
 background-position: bottom;_x000D_
 background-size: 100% 25px;_x000D_
 background-repeat: no-repeat;_x000D_
    border-bottom: 1px solid #000;_x000D_
    border-top: 1px solid red;_x000D_

Node.js https pem error: routines:PEM_read_bio:no start line

Was facing the same problem In my case I changed the option parameter of cert to pfx & removed utf8 encoding.


var options = {
    hostname : 'localhost',
    path : '/',
    method : 'POST',
    cert: fs.readFileSync(testCert, 'utf8'),


var options = {
    hostname : 'localhost',
    path : '/',
    method : 'POST',
    pfx: fs.readFileSync(testCert),

Twitter Bootstrap and ASP.NET GridView

There are 2 steps to resolve this:

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

    <asp:GridView ID="MyGridView" runat="server" UseAccessibleHeader="true">
  2. Add the following Code to the PreRender event:

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

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

Android : Fill Spinner From Java Code Programmatically

// you need to have a list of data that you want the spinner to display
List<String> spinnerArray =  new ArrayList<String>();

ArrayAdapter<String> adapter = new ArrayAdapter<String>(
    this, android.R.layout.simple_spinner_item, spinnerArray);

Spinner sItems = (Spinner) findViewById(;

also to find out what is selected you could do something like this

String selected = sItems.getSelectedItem().toString();
if (selected.equals("what ever the option was")) {

Detect Android phone via Javascript / jQuery

How about this one-liner?

var isAndroid = /(android)/i.test(navigator.userAgent);

The i modifier is used to perform case-insensitive matching.

Technique taken from Cordova AdMob test project:

Gaussian fit for Python

Here is corrected code:

import pylab as plb
import matplotlib.pyplot as plt
from scipy.optimize import curve_fit
from scipy import asarray as ar,exp

x = ar(range(10))
y = ar([0,1,2,3,4,5,4,3,2,1])

n = len(x)                          #the number of data
mean = sum(x*y)/n                   #note this correction
sigma = sum(y*(x-mean)**2)/n        #note this correction

def gaus(x,a,x0,sigma):
    return a*exp(-(x-x0)**2/(2*sigma**2))

popt,pcov = curve_fit(gaus,x,y,p0=[1,mean,sigma])

plt.title('Fig. 3 - Fit for Time Constant')
plt.xlabel('Time (s)')
plt.ylabel('Voltage (V)')

enter image description here

How to output an Excel *.xls file from classic ASP

You can always just export the HTML table to an XLS document. Excel does a pretty good job understanding HTML tables.

Another possiblitly is to export the HTML tables as a CSV or TSV file, but you would need to setup the formatting in your code. This isn't too difficult to accomplish.

There's some classes in the Microsoft.Office.Interop that allow you to create an Excel file programatically, but I have always found them to be a little clumsy. You can find a .NET version of creating a spreadsheet here, which should be pretty easy to modify for classic ASP.

As for .NET, I've always liked CarlosAG's Excel XML Writer Library. It has a nice generator so you can setup your Excel file, save it as an XML spreadsheet and it generates the code to do all the formatting and everything. I know it's not classic ASP, but I thought that I would throw it out there.

With what you're trying above, try adding the header:

"Content-Disposition", "attachment; filename=excelTest.xls"

See if that works. Also, I always use this for the content type:

  Response.ContentType = "application/octet-stream"
    Response.ContentType = "application/"

How to convert an integer to a string in any base?

def base_changer(number,base):
    for i in range(97,buff+1):
        if (mod) in dic.keys():
    if (number) in dic.keys():

    return buff2[::-1]   

How to convert a Base64 string into a Bitmap image to show it in a ImageView?

To anyone who is still interested in this question: If: 1-decodeByteArray returns null 2-Base64.decode throws bad-base64 Exception

Here is the solution: -You should consider the value sent to you from API is Base64 Encoded and should be decoded first in order to cast it to a Bitmap object! -Take a look at your Base64 encoded String, If it starts with


The Base64.decode won't be able to decode it, So it has to be removed from your encoded String:

final String encodedString = "data:image/jpg;base64, ....";                        
final String pureBase64Encoded = encodedString.substring(encodedString.indexOf(",")  + 1);

Now the pureBase64Encoded object is ready to be decoded:

final byte[] decodedBytes = Base64.decode(pureBase64Encoded, Base64.DEFAULT);

Now just simply use the line below to turn this into a Bitmap Object! :

Bitmap decodedBitmap = BitmapFactory.decodeByteArray(decodedBytes, 0, decodedBytes.length);

Or if you're using the great library Glide:


This should do the job! It wasted one day on this and came up to this solution!

Note: If you are still getting bad-base64 error consider other Base64.decode flags like Base64.URL_SAFE and so on

Git Push error: refusing to update checked out branch

Reason:You are pushing to a Non-Bare Repository

There are two types of repositories: bare and non-bare

Bare repositories do not have a working copy and you can push to them. Those are the types of repositories you get in Github! If you want to create a bare repository, you can use

git init --bare

So, in short, you can't push to a non-bare repository (Edit: Well, you can't push to the currently checked out branch of a repository. With a bare repository, you can push to any branch since none are checked out. Although possible, pushing to non-bare repositories is not common). What you can do, is to fetch and merge from the other repository. This is how the pull request that you can see in Github works. You ask them to pull from you, and you don't force-push into them.

Update: Thanks to VonC for pointing this out, in the latest git versions (currently 2.3.0), pushing to the checked out branch of a non-bare repository is possible. Nevertheless, you still cannot push to a dirty working tree, which is not a safe operation anyway.

How to query first 10 rows and next time query other 10 rows from table

LIMIT limit OFFSET offset will work.

But you need a stable ORDER BY clause, or the values may be ordered differently for the next call (after any write on the table for instance).

FROM   msgtable
WHERE  cdate = '2012-07-18'
ORDER  BY msgtable_id  -- or whatever is stable 
OFFSET 50;  -- to skip to page 6

Use standard-conforming date style (ISO 8601 in my example), which works irregardless of your locale settings.

Paging will still shift if involved rows are inserted or deleted or changed in relevant columns. It has to.

To avoid that shift or for better performance with big tables use smarter paging strategies:

Remove duplicates from dataframe, based on two columns A,B, keeping row with max value in another column C

You can do it with drop_duplicates as you wanted

# initialisation
d = pd.DataFrame({'A' : [1,1,2,3,3], 'B' : [2,2,7,4,4],  'C' : [1,4,1,0,8]})

d = d.sort_values("C", ascending=False)
d = d.drop_duplicates(["A","B"])

If it's important to get the same order

d = d.sort_index()

How to display items side-by-side without using tables?

You should float them inside a container that is cleared.


enter image description here

A clean implementation is the "clearfix hack". This is Nicolas Gallagher's version:

 * For modern browsers
 * 1. The space content is one way to avoid an Opera bug when the
 *    contenteditable attribute is included anywhere else in the document.
 *    Otherwise it causes space to appear at the top and bottom of elements
 *    that are clearfixed.
 * 2. The use of `table` rather than `block` is only necessary if using
 *    `:before` to contain the top-margins of child elements.
.clearfix:after {
    content: " "; /* 1 */
    display: table; /* 2 */

.clearfix:after {
    clear: both;

 * For IE 6/7 only
 * Include this rule to trigger hasLayout and contain floats.
.clearfix {
    *zoom: 1;

Can you append strings to variables in PHP?

In PHP use .= to append strings, and not +=.

Why does this output 0? [...] Does PHP not like += with strings?

+= is an arithmetic operator to add a number to another number. Using that operator with strings leads to an automatic type conversion. In the OP's case the strings have been converted to integers of the value 0.

More about operators in PHP:

getActionBar() returns null

Just check the implementation of source code by command click:

    private void initWindowDecorActionBar() {
    Window window = getWindow();

    // Initializing the window decor can change window feature flags.
    // Make sure that we have the correct set before performing the test below.

    if (isChild() || !window.hasFeature(Window.FEATURE_ACTION_BAR) || mActionBar != null) {

    mActionBar = new WindowDecorActionBar(this);


requestWindowFeature(Window.FEATURE_ACTION_BAR); Fixed my issue as I saw requestWindowFeature(Window.FEATURE_ACTION_BAR) is failing; code is open source use it !!

PHP Fatal Error Failed opening required File

Run php -f /common/configs/ to verify the validity of the PHP syntax in the file.

Deep-Learning Nan loss reasons

In my case I got NAN when setting distant integer LABELs. ie:

  • Labels [0..100] the training was ok,
  • Labels [0..100] plus one additional label 8000, then I got NANs.

So, not use a very distant Label.

EDIT You can see the effect in the following simple code:

from keras.models import Sequential
from keras.layers import Dense, Activation
import numpy as np

y=np.random.randint(0,high=5, size=(20,1))

model = Sequential([
            Dense(10, input_dim=X.shape[1]),
model.compile(optimizer = "Adam", loss = "sparse_categorical_crossentropy", metrics = ["accuracy"] )

print('fit model with labels in range 0..5')
history =, y, epochs= 5 )

X = np.vstack( (X, np.random.random(size=(1,5))))
y = np.vstack( ( y, [[8000]]))
print('fit model with labels in range 0..5 plus 8000')
history =, y, epochs= 5 )

The result shows the NANs after adding the label 8000:

fit model with labels in range 0..5
Epoch 1/5
20/20 [==============================] - 0s 25ms/step - loss: 1.8345 - acc: 0.1500
Epoch 2/5
20/20 [==============================] - 0s 150us/step - loss: 1.8312 - acc: 0.1500
Epoch 3/5
20/20 [==============================] - 0s 151us/step - loss: 1.8273 - acc: 0.1500
Epoch 4/5
20/20 [==============================] - 0s 198us/step - loss: 1.8233 - acc: 0.1500
Epoch 5/5
20/20 [==============================] - 0s 151us/step - loss: 1.8192 - acc: 0.1500
fit model with labels in range 0..5 plus 8000
Epoch 1/5
21/21 [==============================] - 0s 142us/step - loss: nan - acc: 0.1429
Epoch 2/5
21/21 [==============================] - 0s 238us/step - loss: nan - acc: 0.2381
Epoch 3/5
21/21 [==============================] - 0s 191us/step - loss: nan - acc: 0.2381
Epoch 4/5
21/21 [==============================] - 0s 191us/step - loss: nan - acc: 0.2381
Epoch 5/5
21/21 [==============================] - 0s 188us/step - loss: nan - acc: 0.2381

Return an empty Observable

You can return Observable.of(empty_variable), for example


// or

// etc

How to resolve "Could not find schema information for the element/attribute <xxx>"?

Have you tried copying the schema file to the XML Schema Caching folder for VS? You can find the location of that folder by looking at VS Tools/Options/Test Editor/XML/Miscellaneous. Unfortunately, i don't know where's the schema file for the MS Enterprise Library 4.0.

Update: After installing MS Enterprise Library, it seems there's no .xsd file. However, there's a tool for editing the configuration - EntLibConfig.exe, which you can use to edit the configuration files. Also, if you add the proper config sections to your config file, VS should be able to parse the config file properly. (EntLibConfig will add these for you, or you can add them yourself). Here's an example for the loggingConfiguration section:

    <section name="loggingConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.LoggingSettings, Microsoft.Practices.EnterpriseLibrary.Logging, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />

You also need to add a reference to the appropriate assembly in your project.

Setting up Gradle for api 26 (Android)

allprojects {
    repositories {
        maven {
            url ""

android {
    compileSdkVersion 26
    buildToolsVersion "26.0.1"
    defaultConfig {
        applicationId "com.keshav.retroft2arrayinsidearrayexamplekeshav"
        minSdkVersion 15
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner ""
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), ''
 compile ''
    compile ''
    compile ''

HTTP 404 Page Not Found in Web Api hosted in IIS 7.5

What kind of HTTP request are you making?

This is a slightly left-field answer but have you tried removing the IIS default error page for 404 to check what your API is actually returning?

I had an issue whereby I wanted a controller method to return a 404 when I POSTed the wrong id to it. I found that I was always getting the IIS 404 "File or directory not found" page rather than the HTTP response from my API. Removing the default 404 error page resolved the problem.

Different issue but you never know it may help ;)

How to turn off Wifi via ADB?

Simple way to switch wifi on non-rooted devices is to use simple app:

public class MainActivity extends Activity {

    public void onCreate(Bundle savedInstanceState) {
        WifiManager wfm = (WifiManager) getSystemService(Context.WIFI_SERVICE);
        try {
        } catch (Exception e) {


<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />

ADB commands:

$ adb shell am start -n org.mytools.config/.MainActivity -e wifi true
$ adb shell am start -n org.mytools.config/.MainActivity -e wifi false

jQuery move to anchor location on page load

Did you tried JQuery's scrollTo method?

Or you can extend JQuery and add your custom mentod:

 scrollToMe: function () {
   var x = jQuery(this).offset().top - 100;
   jQuery('html,body').animate({scrollTop: x}, 400);

Then you can call this method like:


Using grep to search for hex strings in a file

If you want search for printable strings, you can use:

strings -ao filename | grep string

strings will output all printable strings from a binary with offsets, and grep will search within.

If you want search for any binary string, here is your friend:

Call PHP function from jQuery?

This is exactly what ajax is for. See here:

Basically, you ajax/test.php and put the returned HTML code to the element which has the result id.


Of course, you will need to put the functionality which takes time to a new php file (or call the old one with a GET parameter which will activate that functionality only).

Add a properties file to IntelliJ's classpath

I had a similar problem with a log4j.xml file for a unit test, did all of the above. But figured out it was because I was only re-running a failed test....if I re-run the entire test class the correct file is picked up. This is under Intelli-j 9.0.4

How do I get interactive plots again in Spyder/IPython/matplotlib?

You can quickly control this by typing built-in magic commands in Spyder's IPython console, which I find faster than picking these from the preferences menu. Changes take immediate effect, without needing to restart Spyder or the kernel.

To switch to "automatic" (i.e. interactive) plots, type:

%matplotlib auto

then if you want to switch back to "inline", type this:

%matplotlib inline

(Note: these commands don't work in non-IPython consoles)

See more background on this topic: Purpose of "%matplotlib inline"

Installing Bower on Ubuntu

Hi another solution to this problem is to simply add the node nodejs binary folder to your PATH using the following command:

ln -s /usr/bin/nodejs /usr/bin/node

See NPM GitHub for better explanation

Returning value that was passed into a method

The generic Returns<T> method can handle this situation nicely.

_mock.Setup(x => x.DoSomething(It.IsAny<string>())).Returns<string>(x => x);

Or if the method requires multiple inputs, specify them like so:

_mock.Setup(x => x.DoSomething(It.IsAny<string>(), It.IsAny<int>())).Returns((string x, int y) => x);

LINQ Join with Multiple Conditions in On Clause

This works fine for 2 tables. I have 3 tables and on clause has to link 2 conditions from 3 tables. My code:

from p in _dbContext.Products join pv in _dbContext.ProductVariants on p.ProduktId equals pv.ProduktId join jpr in leftJoinQuery on new { VariantId = pv.Vid, ProductId = p.ProduktId } equals new { VariantId = jpr.Prices.VariantID, ProductId = jpr.Prices.ProduktID } into lj

But its showing error at this point: join pv in _dbContext.ProductVariants on p.ProduktId equals pv.ProduktId

Error: The type of one of the expressions in the join clause is incorrect. Type inference failed in the call to 'GroupJoin'.

Scanner method to get a char

To get a char from a Scanner, you can use the findInLine method.

    Scanner sc = new Scanner("abc");
    char ch = sc.findInLine(".").charAt(0);
    System.out.println(ch); // prints "a"
    System.out.println(; // prints "bc"

If you need a bunch of char from a Scanner, then it may be more convenient to (perhaps temporarily) change the delimiter to the empty string. This will make next() returns a length-1 string every time.

    Scanner sc = new Scanner("abc");
    while (sc.hasNext()) {
    } // prints "a", "b", "c"

c# replace \" characters

Try it like this:


This will replace occurrences of \" with empty string.


string t = "\\\"the dog is my friend\\\"";
t = t.Replace("\\\"","");

This will result in:

the dog is my friend

Can I set subject/content of email using mailto:?

Note that it is not possible to use HTML in the message body, according to RFC 2368:

The special hname "body" indicates that the associated hvalue is the body of the message. The "body" hname should contain the content for the first text/plain body part of the message. The mailto URL is primarily intended for generation of short text messages that are actually the content of automatic processing (such as "subscribe" messages for mailing lists), not general MIME bodies.


How to have stored properties in Swift, the same way I had on Objective-C?

I found this solution more practical

UPDATED for Swift 3

extension UIColor {

    static let graySpace = UIColor.init(red: 50/255, green: 50/255, blue: 50/255, alpha: 1.0)
    static let redBlood = UIColor.init(red: 102/255, green: 0/255, blue: 0/255, alpha: 1.0)
    static let redOrange = UIColor.init(red: 204/255, green: 17/255, blue: 0/255, alpha: 1.0)

    func alpha(value : CGFloat) -> UIColor {
        var r = CGFloat(0), g = CGFloat(0), b = CGFloat(0), a = CGFloat(0)
        self.getRed(&r, green: &g, blue: &b, alpha: &a)
        return UIColor(red: r, green: g, blue: b, alpha: value)


...then in your code

class gameController: UIViewController {

    @IBOutlet var game: gameClass!

    override func viewDidLoad() {
        self.view.backgroundColor = UIColor.graySpace


Invalid argument supplied for foreach()

$values = get_values();

foreach ((array) $values as $value){

Problem is always null and Casting is in fact the cleaning solution.

Save ArrayList to SharedPreferences

Saving and retrieving the ArrayList From SharedPreference
 public static void addToPreference(String id,Context context) {
        SharedPreferences sharedPreferences = context.getSharedPreferences(Constants.MyPreference, Context.MODE_PRIVATE);
        ArrayList<String> list = getListFromPreference(context);
        if (!list.contains(id)) {
            SharedPreferences.Editor edit = sharedPreferences.edit();
            Set<String> set = new HashSet<>();
            edit.putStringSet(Constant.LIST, set);

    public static ArrayList<String> getListFromPreference(Context context) {
        SharedPreferences sharedPreferences = context.getSharedPreferences(Constants.MyPreference, Context.MODE_PRIVATE);
        Set<String> set = sharedPreferences.getStringSet(Constant.LIST, null);
        ArrayList<String> list = new ArrayList<>();
        if (set != null) {
            list = new ArrayList<>(set);
        return list;

Finding median of list in Python

I defined a median function for a list of numbers as

def median(numbers):
    return (sorted(numbers)[int(round((len(numbers) - 1) / 2.0))] + sorted(numbers)[int(round((len(numbers) - 1) // 2.0))]) / 2.0

Invoking a static method using reflection

public class Add {
    static int add(int a, int b){
        return (a+b);

In the above example, 'add' is a static method that takes two integers as arguments.

Following snippet is used to call 'add' method with input 1 and 2.

Class myClass = Class.forName("Add");
Method method = myClass.getDeclaredMethod("add", int.class, int.class);
Object result = method.invoke(null, 1, 2);

Reference link.

How to use PrintWriter and File classes in Java?


public class Testing {

  public static void main(String[] args) throws IOException {

    File file = new File ("C:/Users/Me/Desktop/directory/file.txt");
    PrintWriter printWriter = new PrintWriter ("file.txt");
    printWriter.println ("hello");
    printWriter.close ();       

throw an exception for the file.

How to inspect FormData?

Here's a function to log entries of a FormData object to the console as an object.

export const logFormData = (formData) => {
    const entries = formData.entries();
    const result = {};
    let next;
    let pair;
    while ((next = && next.done === false) {
        pair = next.value;
        result[pair[0]] = pair[1];

MDN doc on .entries()

MDN doc on .next() and .done

SVN 405 Method Not Allowed

If you use to host your Subversion repository.

You know below things, right?

If you plan to make changes, use this command to check out the code as yourself using HTTPS:

# Project members authenticate over HTTPS to allow committing changes.
svn checkout https://.../svn/trunk/ user-...

When prompted, enter your generated password.
Use this command to anonymously check out the latest project source code:

# Non-members may check out a read-only working copy anonymously over HTTP.
svn checkout http://.../svn/trunk/ ...-read-only

The error you mentioned exactly you are using Non-members may check out a read-only working copy anonymously over HTTP status. Therefore, you can not commit or do anything so far.

You must use Project members authenticate over HTTPS to allow committing changes thing.

It will be fine now.

Is there a cross-domain iframe height auto-resizer that works?

Here is an alternative implementation.

enter image description here

Basically if you able to edit page at other domain you can place another iframe page that belongs to your server which saving height to cookies. With an interval read cookies when it is updated, update the height of the iframe. That is all.

Edit: 2019 December

The solution above basically uses another iframe inside of an iframe 3rd iframe is belongs to the top page domain, which you call this page with a query string that saves size value to a cookie, outer page checks this query with some interval. But it is not a good solution so you should follow this one:

In Top page :

window.addEventListener("message", (m)=>{iframeResizingFunction(m)});

Here you can check m.origin to see where is it comes from.

In frame page:

window.parent.postMessage({ width: 640, height:480 }, "*")

Although, please don't forget this is not so secure way. To make it secure update * value (targetOrigin) with your desired value. Please follow documentation:

SQL Update to the SUM of its joined values

Use a sub query similar to the below.

SET extrasPrice = sub.TotalPrice from
BookingPitches p
inner join 
(Select PitchID, Sum(Price) TotalPrice
    from  dbo.BookingPitchExtras
    Where [Required] = 1
    Group by Pitchid
) as Sub
on p.Id = e.PitchId 
where p.BookingId = 1

Connecting to local SQL Server database using C#

In Data Source (on the left of Visual Studio) right click on the database, then Configure Data Source With Wizard. A new window will appear, expand the Connection string, you can find the connection string in there

cURL equivalent in Node.js?

See the documentation for the HTTP module for a full example:

CakePHP 3.0 installation: intl extension missing from system

Intl Means :Internationalization extension which enables programmers to perform UCA-conformant collation and number,currency,date,time formatting in PHP scripts.

To enable PHP Intl with PECL can be used.

pecl install intl

On a plain RHEL/CentOS/Fedora, PHP Intl can be install using yum

yum install php-intl

On Ubuntu, PHP Intl can be install using apt-get

 apt-get install php5-intl

Restart Apache service for the changes to take effect.

That's it

How to merge rows in a column into one cell in excel?

I know this is really a really old question, but I was trying to do the same thing and I stumbled upon a new formula in excel called "TEXTJOIN".

For the question, the following formula solves the problem


The signature of "TEXTJOIN" is explained as TEXTJOIN(delimiter,ignore_empty,text1,[text2],[text3],...)

Decrementing for loops

You need to give the range a -1 step

 for i in range(10,0,-1):
    print i

Python3 project remove __pycache__ folders and .pyc files

Since this is a Python 3 project, you only need to delete __pycache__ directories -- all .pyc/.pyo files are inside them.

find . -type d -name __pycache__ -exec rm -r {} \+

or its simpler form,

find . -type d -name __pycache__ -delete

which didn't work for me for some reason (files were deleted but directories weren't), so I'm including both for the sake of completeness.

Alternatively, if you're doing this in a directory that's under revision control, you can tell the RCS to ignore __pycache__ folders recursively. Then, at the required moment, just clean up all the ignored files. This will likely be more convenient because there'll probably be more to clean up than just __pycache__.

Auto increment in MongoDB to store sequence of Unique User ID

First Record should be add

"_id" = 1    in your db

$database = "demo";
$collections ="democollaction";
echo getnextid($database,$collections);

function getnextid($database,$collections){

     $m = new MongoClient();
    $db = $m->selectDB($database);
    $cursor = $collection->find()->sort(array("_id" => -1))->limit(1);
    $array = iterator_to_array($cursor);

    foreach($array as $value){

        return $value["_id"] + 1;


Android: remove notification from notification bar

You can also call cancelAll on the notification manager, so you don't even have to worry about the notification ids.

NotificationManager notifManager= (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

EDIT : I was downvoted so maybe I should specify that this will only remove the notification from your application.

PHP Fatal error: Class 'PDO' not found

If you run php with php-fpm module,do not forget to run command systemctl restart php-fpm!That will reload php-fpm module.

How do I fix the error "Only one usage of each socket address (protocol/network address/port) is normally permitted"?

You are debugging two or more times. so the application may run more at a time. Then only this issue will occur. You should close all debugging applications using task-manager, Then debug again.

How can I create an MSI setup?

You can use Visual Studio - that's paid.

You can use - that has a free edition.

You can use - for example Winamp uses this installer - and is very configurable and is Open Source.

How to create a Java / Maven project that works in Visual Studio Code?

An alternative way is to install the Maven for Java plugin and create a maven project within Visual Studio. The steps are described in the official documentation:

  1. From the Command Palette (Crtl+Shift+P), select Maven: Generate from Maven Archetype and follow the instructions, or
  2. Right-click on a folder and select Generate from Maven Archetype.

Ignore .pyc files in git repository

If you want to ignore '.pyc' files globally (i.e. if you do not want to add the line to .gitignore file in every git directory), try the following:

$ cat ~/.gitconfig 
    excludesFile = ~/.gitignore
$ cat ~/.gitignore


  • Patterns which a user wants Git to ignore in all situations (e.g., backup or temporary files generated by the user’s editor of choice) generally go into a file specified by core.excludesFile in the user’s ~/.gitconfig.

  • A leading "**" followed by a slash means match in all directories. For example, "**/foo" matches file or directory "foo" anywhere, the same as pattern "foo". "**/foo/bar" matches file or directory "bar" anywhere that is directly under directory "foo".

IF a cell contains a string

SEARCH does not return 0 if there is no match, it returns #VALUE!. So you have to wrap calls to SEARCH with IFERROR.

For example...

=IF(IFERROR(SEARCH("cat", A1), 0), "cat", "none")



Here, IFERROR returns the value from SEARCH when it works; the given value of 0 otherwise.

How can I check if string contains characters & whitespace, not just whitespace?

This can be fast solution

return input < "\u0020" + 1;

SQL Server datetime LIKE select?

There's no direct support for LIKE operator against DATETIME variables, but you can always cast the DATETIME to a VARCHAR:

SELECT (list of fields) FROM YourTable
WHERE CONVERT(VARCHAR(25), register_date, 126) LIKE '2009-10-10%'

Check the MSDN docs for a complete list of available "styles" in the CONVERT function.


How to set time zone of a java.util.Date?

This code was helpful in an app I'm working on:

    Instant date = null;
    Date sdf = null;
    String formatTemplate = "EEE MMM dd yyyy HH:mm:ss";
    try {
        SimpleDateFormat isoFormat = new SimpleDateFormat("EEE MMM dd yyyy HH:mm:ss");
        sdf = isoFormat.parse(timeAtWhichToMakeAvailable);
        date = sdf.toInstant();

    } catch (Exception e) {
        System.out.println("did not parse: " + timeAtWhichToMakeAvailable);
    }"timeAtWhichToMakeAvailable: " + timeAtWhichToMakeAvailable);"sdf: " + sdf);"parsed to: " + date);

Add placeholder text inside UITextView in Swift?

Floating Placeholder

It's simple, safe and reliable to position a placeholder label above a text view, set its font, color and manage placeholder visibility by tracking changes to the text view's character count.

Swift 3:

class NotesViewController : UIViewController, UITextViewDelegate {

    @IBOutlet var textView : UITextView!
    var placeholderLabel : UILabel!

    override func viewDidLoad() {

        textView.delegate = self
        placeholderLabel = UILabel()
        placeholderLabel.text = "Enter some text..."
        placeholderLabel.font = UIFont.italicSystemFont(ofSize: (textView.font?.pointSize)!)
        placeholderLabel.frame.origin = CGPoint(x: 5, y: (textView.font?.pointSize)! / 2)
        placeholderLabel.textColor = UIColor.lightGray
        placeholderLabel.isHidden = !textView.text.isEmpty

    func textViewDidChange(_ textView: UITextView) {
        placeholderLabel.isHidden = !textView.text.isEmpty

Swift 2: Same, except:italicSystemFontOfSize(textView.font.pointSize), UIColor.lightGrayColor

How can I reverse a NSArray in Objective-C?

NSMutableArray *objMyObject = [NSMutableArray arrayWithArray:[self reverseArray:objArrayToBeReversed]];

// Function reverseArray 
-(NSArray *) reverseArray : (NSArray *) myArray {   
    return [[myArray reverseObjectEnumerator] allObjects];

Update query PHP MySQL

You have to have single quotes around any VARCHAR content in your queries. So your update query should be:

mysql_query("UPDATE blogEntry SET content = '$udcontent', title = '$udtitle' WHERE id = $id");

Also, it is bad form to update your database directly with the content from a POST. You should sanitize your incoming data with the mysql_real_escape_string function.

Could not load file or assembly 'Microsoft.Web.Infrastructure,

I found that even though it worked on my dev box, the assembly wasn't added to the project. Search for Microsoft.Web.Infrastructure in NuGet and install it from there. Then, make sure it has Copy Local selected.

Time part of a DateTime Field in SQL

                 CONVERT(VARCHAR(17), A.SOURCE_DEPARTURE_TIME, 108)  
      CONVERT(VARCHAR(17), A.SOURCE_DEPARTURE_TIME, 108) BETWEEN '15:00:00' AND '15:45:00'

Python Matplotlib Y-Axis ticks on Right Side of Plot

Use ax.yaxis.tick_right()

for example:

from matplotlib import pyplot as plt

f = plt.figure()
ax = f.add_subplot(111)

enter image description here

How to set header and options in axios?

This is a simple example of a configuration with headers and responseType:

var config = {
  headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
  responseType: 'blob'
};'http://YOUR_URL',, config)
  .then((response) => {

Content-Type can be 'application/x-www-form-urlencoded' or 'application/json' and it may work also 'application/json;charset=utf-8'

responseType can be 'arraybuffer', 'blob', 'document', 'json', 'text', 'stream'

In this example, is the data you want to send. It can be a value or an Array. (If you want to send an object you'll probably have to serialize it)

Xml Parsing in C#

First add an Enrty and Category class:

public class Entry {     public string Id { get; set; }     public string Title { get; set; }     public string Updated { get; set; }     public string Summary { get; set; }     public string GPoint { get; set; }     public string GElev { get; set; }     public List<string> Categories { get; set; } }  public class Category {     public string Label { get; set; }     public string Term { get; set; } } 

Then use LINQ to XML

XDocument xDoc = XDocument.Load("path");          List<Entry> entries = (from x in xDoc.Descendants("entry")             select new Entry()             {                 Id = (string) x.Element("id"),                 Title = (string)x.Element("title"),                 Updated = (string)x.Element("updated"),                 Summary = (string)x.Element("summary"),                 GPoint = (string)x.Element("georss:point"),                 GElev = (string)x.Element("georss:elev"),                 Categories = (from c in x.Elements("category")                                   select new Category                                   {                                       Label = (string)c.Attribute("label"),                                       Term = (string)c.Attribute("term")                                   }).ToList();             }).ToList(); 

How to change the color of a CheckBox?

you can set android theme of the checkbox to get the color you want in your styles.xml add :

<style name="checkBoxStyle" parent="Base.Theme.AppCompat">
    <item name="colorAccent">CHECKEDHIGHLIGHTCOLOR</item>
    <item name="android:textColorSecondary">UNCHECKEDCOLOR</item>

then in your layout file :


unlike using android:buttonTint="@color/CHECK_COLOR" this method works under Api 23

How to run Rake tasks from within Rake tasks?

task :build_all do
  [ :debug, :release ].each do |t|
    $build_type = t

That should sort you out, just needed the same thing myself.

Executing an EXE file using a PowerShell script

It looks like you're specifying both the EXE and its first argument in a single string e.g; '"C:\Program Files\Automated QA\TestExecute 8\Bin\TestExecute.exe" C:\temp\TestProject1\TestProject1.pjs /run /exit /SilentMode'. This won't work. In general you invoke a native command that has a space in its path like so:

& "c:\some path with spaces\foo.exe" <arguments go here>

That is & expects to be followed by a string that identifies a command: cmdlet, function, native exe relative or absolute path.

Once you get just this working:

& "c:\some path with spaces\foo.exe"

Start working on quoting of the arguments as necessary. Although it looks like your arguments should be just fine (no spaces, no other special characters interpreted by PowerShell).

Operator overloading on class templates

You must specify that the friend is a template function:

MyClass<T>& operator+=<>(const MyClass<T>& classObj);

See this C++ FAQ Lite answer for details.

Regex pattern to match at least 1 number and 1 character in a string

If you need the digit to be at the end of any word, this worked for me:

  • \b word boundary
  • [a-zA-Z] any letter
  • [0-9] any number
  • "+" unlimited search (show all results)

How to add an element to a list?

import json

myDict = {'dict': [{'a': 'none', 'b': 'none', 'c': 'none'}]}
test = json.dumps(myDict)

{"dict": [{"a": "none", "b": "none", "c": "none"}]}

myDict['dict'].append(({'a': 'aaaa', 'b': 'aaaa', 'c': 'aaaa'}))
test = json.dumps(myDict)

{"dict": [{"a": "none", "b": "none", "c": "none"}, {"a": "aaaa", "b": "aaaa", "c": "aaaa"}]}

Flash CS4 refuses to let go

Do you have several swf-files? If your class is imported in one of the swf's, other swf's will also use the same version of the class. One old import with * in one swf will do it. Recompile everything and see if it works.

Executing Batch File in C#

System.Diagnostics.Process.Start(BatchFileName, Parameters);

I know this will work for batch file and parameters, but no ideas how to get the results in C#. Usually, the outputs are defined in the batch file.

Exiting from python Command Line

"exit" is a valid variable name that can be used in your Python program. You wouldn't want to exit the interpreter when you're just trying to see the value of that variable.

How do you copy and paste into Git Bash

I use the mouse:

  1. mark
  2. right click -> copy
  3. right click -> paste

Remove multiple items from a Python list in just one statement

I don't know why everyone forgot to mention the amazing capability of sets in python. You can simply cast your list into a set and then remove whatever you want to remove in a simple expression like so:

>>> item_list = ['item', 5, 'foo', 3.14, True]
>>> item_list = set(item_list) - {'item', 5}
>>> item_list
{True, 3.14, 'foo'}
>>> # you can cast it again in a list-from like so
>>> item_list = list(item_list)
>>> item_list
[True, 3.14, 'foo']

Cygwin - Makefile-error: recipe for target `main.o' failed

You see the two empty -D entries in the g++ command line? They're causing the problem. You must have values in the -D items e.g. -DWIN32

if you're insistent on using something like -D$(SYSTEM) -D$(ENVIRONMENT) then you can use something like:

SYSTEM ?= generic
ENVIRONMENT ?= generic

in the makefile which gives them default values.

Your output looks to be missing the all important output:

<command-line>:0:1: error: macro names must be identifiers
<command-line>:0:1: error: macro names must be identifiers

just to clarify, what actually got sent to g++ was -D -DWindows_NT, i.e. define a preprocessor macro called -DWindows_NT; which is of course not a valid identifier (similarly for -D -I.)

How do I extract text that lies between parentheses (round brackets)?

Assuming that you only have one pair of parenthesis.

string s = "User name (sales)";
int start = s.IndexOf("(") + 1;
int end = s.IndexOf(")", start);
string result = s.Substring(start, end - start);

nginx - client_max_body_size has no effect

Please see if you are setting client_max_body_size directive inside http {} block and not inside location {} block. I have set it inside http{} block and it works

How to add parameters into a WebRequest?

Use stream to write content to webrequest

string data = "username=<value>&password=<value>"; //replace <value>
byte[] dataStream = Encoding.UTF8.GetBytes(data);
private string urlPath = "";
string request = urlPath + "index.php/org/get_org_form";
WebRequest webRequest = WebRequest.Create(request);
webRequest.Method = "POST";
webRequest.ContentType = "application/x-www-form-urlencoded";
webRequest.ContentLength = dataStream.Length;  
Stream newStream=webRequest.GetRequestStream();
// Send the data.
WebResponse webResponse = webRequest.GetResponse();  

How can you represent inheritance in a database?

With the information provided, I'd model the database to have the following:


  • POLICY_ID (primary key)


  • LIABILITY_ID (primary key)
  • POLICY_ID (foreign key)


  • PROPERTY_ID (primary key)
  • POLICY_ID (foreign key)

...and so on, because I'd expect there to be different attributes associated with each section of the policy. Otherwise, there could be a single SECTIONS table and in addition to the policy_id, there'd be a section_type_code...

Either way, this would allow you to support optional sections per policy...

I don't understand what you find unsatisfactory about this approach - this is how you store data while maintaining referential integrity and not duplicating data. The term is "normalized"...

Because SQL is SET based, it's rather alien to procedural/OO programming concepts & requires code to transition from one realm to the other. ORMs are often considered, but they don't work well in high volume, complex systems.

gcc-arm-linux-gnueabi command not found

I was also facing the same issue and resolved it after installing the following dependency:

sudo apt-get install lib32z1-dev

Is it possible to set a timeout for an SQL query on Microsoft SQL server?

I might suggest 2 things.

1) If your query takes a lot of time because it´s using several tables that might involve locks, a quite fast solution is to run your queries with the "NoLock" hint.

Simply add Select * from YourTable WITH (NOLOCK) in all your table references an that will prevent your query to block for concurrent transactions.

2) if you want to be sure that all of your queries runs in (let´s say) less than 5 seconds, then you could add what @talha proposed, that worked sweet for me

Just add at the top of your execution

SET LOCK_TIMEOUT 5000;   --5 seconds.

And that will cause that your query takes less than 5 or fail. Then you should catch the exception and rollback if needed.

Hope it helps.

Form Submit Execute JavaScript Best Practice?

Use the onsubmit event to execute JavaScript code when the form is submitted. You can then return false or call the passed event's preventDefault method to disable the form submission.

For example:

function doSomething() {
    alert('Form submitted!');
    return false;

<form onsubmit="return doSomething();" class="my-form">
    <input type="submit" value="Submit">

This works, but it's best not to litter your HTML with JavaScript, just as you shouldn't write lots of inline CSS rules. Many Javascript frameworks facilitate this separation of concerns. In jQuery you bind an event using JavaScript code like so:

$('.my-form').on('submit', function () {
    alert('Form submitted!');
    return false;

<form class="my-form">
    <input type="submit" value="Submit">

Should I use the datetime or timestamp data type in MySQL?

  1. TIMESTAMP is four bytes vs eight bytes for DATETIME.

  2. Timestamps are also lighter on the database and indexed faster.

  3. The DATETIME type is used when you need values that contain both date and time information. MySQL retrieves and displays DATETIME values in ‘YYYY-MM-DD HH:MM:SS’ format. The supported range is ’1000-01-01 00:00:00' to ’9999-12-31 23:59:59'.

The TIMESTAMP data type has a range of ’1970-01-01 00:00:01' UTC to ’2038-01-09 03:14:07' UTC. It has varying properties, depending on the MySQL version and the SQL mode the server is running in.

  1. DATETIME is constant while TIMESTAMP is effected by the time_zone setting.

HTML img tag: title attribute vs. alt attribute?

ALT Attribute

The alt attribute is defined in a set of tags (namely, img, area and optionally for input and applet) to allow you to provide a text equivalent for the object.

A text equivalent brings the following benefits to your web site and its visitors in the following common situations:

  • nowadays, Web browsers are available in a very wide variety of platforms with very different capacities; some cannot display images at all or only a restricted set of type of images; some can be configured to not load images. If your code has the alt attribute set in its images, most of these browsers will display the description you gave instead of the images
  • some of your visitors cannot see images, be they blind, color-blind, low-sighted; the alt attribute is of great help for those people that can rely on it to have a good idea of what's on your page
  • search engine bots belong to the two above categories: if you want your website to be indexed as well as it deserves, use the alt attribute to make sure that they won't miss important sections of your pages.

Title Attribute

The objective of this technique is to provide context sensitive help for users as they enter data in forms by providing the help information in a title attribute. The help may include format information or examples of input.

Example 1: A pulldown menu that limits the scope of a search
A search form uses a pulldown menu to limit the scope of the search. The pulldown menu is immediately adjacent to the text field used to enter the search term. The relationship between the search field and the pulldown menu is clear to users who can see the visual design, which does not have room for a visible label. The title attribute is used to identify the select menu. The title attribute can be spoken by screen readers or displayed as a tool tip for people using screen magnifiers.

<label for="searchTerm">Search for:</label>
<input id="searchTerm" type="text" size="30" value="" name="searchTerm">
<select title="Search in" id="scope">

Example 2: Input fields for a phone number
A Web page contains controls for entering a phone number in the United States, with three fields for area code, exchange, and last four digits.

    <legend>Phone number</legend>
    <input id="areaCode" name="areaCode" title="Area Code" type="text" size="3" value="" >
    <input id="exchange" name="exchange" title="First three digits of phone number" type="text" size="3" value="" >
    <input id="lastDigits" name="lastDigits" title="Last four digits of phone number" type="text" size="4" value="" >

Example 3: A Search Function A Web page contains a text field where the user can enter search terms and a button labeled "Search" for performing the search. The title attribute is used to identify the form control and the button is positioned right after the text field so that it is clear to the user that the text field is where the search term should be entered.

<input type="text" title="Type search term here"/> <input type="submit" value="Search"/>

Example 4: A data table of form controls
A data table of form controls needs to associate each control with the column and row headers for that cell. Without a title (or off-screen LABEL) it is difficult for non-visual users to pause and interrogate for corresponding row/column header values using their assistive technology while tabbing through the form.

For example, a survey form has four column headers in first row: Question, Agree, Undecided, Disagree. Each following row contains a question and a radio button in each cell corresponding to answer choice in the three columns. The title attribute for every radio button is a concatenation of the answer choice (column header) and the text of the question (row header) with a hyphen or colon as a separator.

Img Element

Allowed attributes mentioned at MDN.

  • alt
  • crossorigin
  • decoding
  • height
  • importance (experimental api)
  • intrinsicsize (experimental api)
  • ismap
  • referrerpolicy (experimental api)
  • src
  • srcset
  • width
  • usemap

As you can see title attribute is not allowed inside img element. I would use alt attribute and if requires I would use CSS (Example: pseudo class :hover) instead of title attribute.

How to increase the gap between text and underlining in CSS

I know it's an old question, but for single line text setting display: inline-block and then setting the height has worked well for me to control the distance between a border and the text.

How do I find the data directory for a SQL Server instance?

Alex's answer is the right one, but for posterity here's another option: create a new empty database. If you use CREATE DATABASE without specifying a target dir you get... the default data / log directories. Easy.

Personally however I'd probably either:

  • RESTORE the database to the developer's PC, rather than copy/attach (backups can be compressed, exposed on a UNC), or
  • Use a linked server to avoid doing this in the first place (depends how much data goes over the join)

ps: 20gb is not huge, even in 2015. But it's all relative.

how do I get a new line, after using float:left?

You need to "clear" the float after every 6 images. So with your current code, change the styles for containerdivNewLine to:

.containerdivNewLine { clear: both; float: left; display: block; position: relative; } 

Boolean.parseBoolean("1") = false...?

I had the same question and i solved it with that:

Boolean use_vote = o.get('uses_votes').equals("1") ? true : false;

How are environment variables used in Jenkins with Windows Batch Command?

I should this On Windows, environment variable expansion is %BUILD_NUMBER%

Why is there no xrange function in Python3?

One way to fix up your python2 code is:

import sys

if sys.version_info >= (3, 0):
    def xrange(*args, **kwargs):
        return iter(range(*args, **kwargs))

Request redirect to /Account/Login?ReturnUrl=%2f since MVC 3 install on server

Similar setup, identical problem. Some installations would work, but most would start redirecting (http 302) to /Account/Login?ReturnUrl=%2f after a successful login, even though we're not using Forms Authentication. In my case after trying everything else, the solution was to switch the Application Pool Managed Pipeline Mode from from Integrated to Classic, which cleared up the problem immediately.

How do I use cx_freeze?

find the cxfreeze script and run it. It will be in the same path as your other python helper scripts, such as pip.

cxfreeze --target-dir dist

read more at:

Partial Dependency (Databases)

A FD (functional dependency) that holds in a relation is partial when removing one of the determining attributes gives a FD that holds in the relation. A FD that isn't partial is full.

Eg: If {A,B} ? {C} but also {A} ? {C} then {C} is partially functionally dependent on {A,B}.

Eg: Here's a relation value where that example condition holds. (A FD holds in a relation variable when it holds in every value that can arise.)

A  B  C
1  1  1
1  2  1
2  1  1

The non-trivial FDs that hold: {A,B} determines {C}, {B,C}, {A,C} & {A,B,C}; {A}, {B} & {} also determine {C}. Of those: {A,B} ? {C} is partial per {A} ? {C}, {B} ? {C} & {} ? {C}; {A} ? {C} & {B} ? {C} are partial per {} ? {C}; the others are full.

A functional dependency X ? Y is a full functional dependency if removal of any attribute A from X means that the dependency does not hold any more; that is, for any attribute A e X, (X – {A}) does not functionally determine Y. A functional dependency X ? Y is a partial dependency if some attribute A e X can be removed from X and the dependency still holds; that is, for some A e X, (X – {A}) ? Y.

-- FUNDAMENTALS OF Database Systems SIXTH EDITION Ramez Elmasri & Navathe

Notice that whether a FD is full vs partial doesn't depend on CKs (candidate keys), let alone one CK that you might be calling the PK (primary key).

(A definition of 2NF is that every non-CK attribute is fully functionally determined by every CK. Observe that the only CK is {A,B} & the only non-CK attribute C is partially dependent on it so this value is not in 2NF & indeed it is the lossless join of components/projections onto {A,B} & {A,C}, onto {A,B} & {B,C} & onto {A,B} & {C}.)

(Beware that that textbook's definition of "transitive FD" does not define the same sort of thing as the standard definition of "transitive FD".)

Why is SQL server throwing this error: Cannot insert the value NULL into column 'id'?

In my case,

I was trying to update my model by making a foreign key required, but the database had "null" data in it already in some columns from previously entered data. So every time i run update-database...i got the error.

I SOLVED it by manually deleting from the database all rows that had null in the column i was making required.

What is the difference between bindParam and bindValue?

From the manual entry for PDOStatement::bindParam:

[With bindParam] Unlike PDOStatement::bindValue(), the variable is bound as a reference and will only be evaluated at the time that PDOStatement::execute() is called.

So, for example:

$sex = 'male';
$s = $dbh->prepare('SELECT name FROM students WHERE sex = :sex');
$s->bindParam(':sex', $sex); // use bindParam to bind the variable
$sex = 'female';
$s->execute(); // executed with WHERE sex = 'female'


$sex = 'male';
$s = $dbh->prepare('SELECT name FROM students WHERE sex = :sex');
$s->bindValue(':sex', $sex); // use bindValue to bind the variable's value
$sex = 'female';
$s->execute(); // executed with WHERE sex = 'male'

is not JSON serializable

It's worth noting that the QuerySet.values_list() method doesn't actually return a list, but an object of type django.db.models.query.ValuesListQuerySet, in order to maintain Django's goal of lazy evaluation, i.e. the DB query required to generate the 'list' isn't actually performed until the object is evaluated.

Somewhat irritatingly, though, this object has a custom __repr__ method which makes it look like a list when printed out, so it's not always obvious that the object isn't really a list.

The exception in the question is caused by the fact that custom objects cannot be serialized in JSON, so you'll have to convert it to a list first, with...

my_list = list(self.get_queryset().values_list('code', flat=True))

...then you can convert it to JSON with...

json_data = json.dumps(my_list)

You'll also have to place the resulting JSON data in an HttpResponse object, which, apparently, should have a Content-Type of application/json, with...

response = HttpResponse(json_data, content_type='application/json')

...which you can then return from your function.

How to set a text box for inputing password in winforms?

private void cbShowHide_CheckedChanged(object sender, EventArgs e)
    if (cbShowHide.Checked)
        txtPin.UseSystemPasswordChar = PasswordPropertyTextAttribute.No.Password;
        //Hides Textbox password
        txtPin.UseSystemPasswordChar = PasswordPropertyTextAttribute.Yes.Password;

Copy this code to show and hide your textbox using a checkbox

How do you use NSAttributedString?

I wrote helper to add attributes easily:

- (void)addColor:(UIColor *)color substring:(NSString *)substring;
- (void)addBackgroundColor:(UIColor *)color substring:(NSString *)substring;
- (void)addUnderlineForSubstring:(NSString *)substring;
- (void)addStrikeThrough:(int)thickness substring:(NSString *)substring;
- (void)addShadowColor:(UIColor *)color width:(int)width height:(int)height radius:(int)radius substring:(NSString *)substring;
- (void)addFontWithName:(NSString *)fontName size:(int)fontSize substring:(NSString *)substring;
- (void)addAlignment:(NSTextAlignment)alignment substring:(NSString *)substring;
- (void)addColorToRussianText:(UIColor *)color;
- (void)addStrokeColor:(UIColor *)color thickness:(int)thickness substring:(NSString *)substring;
- (void)addVerticalGlyph:(BOOL)glyph substring:(NSString *)substring;

You can install through CocoaPods also : pod 'MASAttributes', '~> 1.0.0'

How to remove entity with ManyToMany relationship in JPA (and corresponding join table rows)?

This is what I ended up doing. Hopefully someone might find it useful.

public void deleteGroup(Long groupId) {
    Group group = groupRepository.findById(groupId).orElseThrow();
    group.getUsers().forEach(u -> u.getGroups().remove(group));

How to get docker-compose to always re-create containers from fresh images?

The only solution that worked for me was this command :

docker-compose build --no-cache

This will automatically pull fresh image from repo and won't use the cache version that is prebuild with any parameters you've been using before.

Getting input values from text box

  function submit(){
      var userPass = document.getElementById('pass');
      var userName = document.getElementById('user');

<input type="text" id="user" />
<input type="text" id="pass" />
<button onclick="submit();" href="javascript:;">Submit</button>

'NOT NULL constraint failed' after adding to

@coldmind answer is correct but lacks details.

The 'NOT NULL constraint failed' occurs when something tries to set None to the 'zipcode' property, while it has not been explicitely allowed.

It usually happens when:

1) your field has Null=False by default, so that the value in the database cannot be None (i.e. undefined) when the object is created and saved in the database (this happens after a objects_set.create() call or setting the .zipcode property and doing a .save() call).

For instance, if somewhere in your code an assignement results in:

model.zipcode = None

this error is raised

2) When creating or updating the database, Django is constrained to find a default value to fill the field, because Null=False by default. It does not find any because you haven't defined any. So this error can not only happen during code execution but also when creating the database?

3) Note that the same error would be returned of you define default=None, or if your default value with an incorrect type, for instance default='00000' instead of 00000 for your field (maybe can there be automatic conversion between char and integers, but I would advise against relying on it. Besides, explicit is better than implicit). Most likely an error would also be raised if the default value violates the max_length property, e.g. 123456

So you'll have to define the field by one of the following:

models.IntegerField(_('zipcode'), max_length=5, Null=True,

models.IntegerField(_('zipcode'), max_length=5, Null=False,
   blank=True, default=00000)

models.IntegerField(_('zipcode'), max_length=5, blank=True,

and then make a migration (python3 makemigration ) and then migrate (python3 migrate).

For safety you can also delete the last failed migration files in <app_name>/migrations/, there are usually named after this pattern:


Finally, if you don't set Null=True, make sure that mode.zipcode = None is never done anywhere.

How do you send an HTTP Get Web Request in Python?

In Python, you can use urllib2 ( to do all of that work for you.

Simply enough:

import urllib2
f =  urllib2.urlopen(url)

Will print the received HTTP response.

To pass GET/POST parameters the urllib.urlencode() function can be used. For more information, you can refer to the Official Urllib2 Tutorial

How to remove an iOS app from the App Store

To remove an app from the App Store, deselect all territories in your app's Rights and Pricing section on the App Summary page accessible from the Manage Your Applications module. Your app status will change to Developer Removed from Sale and will be removed from the App Store until you make it available again using the Rights and Pricing section.

MongoNetworkError: failed to connect to server [localhost:27017] on first connect [MongoNetworkError: connect ECONNREFUSED]

this might help someone if you installed your mongo on .msi setup kindly open the software and select repair instead of install and try again, that works for me .

Multiple models in a view

a simple way to do that

we can call all model first

@using project.Models

then send your model with viewbag

// for list
ViewBag.Name = db.YourModel.ToList();

// for one
ViewBag.Name = db.YourModel.Find(id);

and in view

// for list
List<YourModel> Name = (List<YourModel>)ViewBag.Name ;

//for one
YourModel Name = (YourModel)ViewBag.Name ;

then easily use this like Model

MySQL Query to select data from last week?

You can also use it esay way

FROM   inventory

Delete all rows in an HTML table

This works in IE without even having to declare a var for the table and will delete all rows:

for(var i = 0; i < resultsTable.rows.length;)

When to use window.opener / window.parent /

top, parent, opener (as well as window, self, and iframe) are all window objects.

  1. window.opener -> returns the window that opens or launches the current popup window.
  2. -> returns the topmost window, if you're using frames, this is the frameset window, if not using frames, this is the same as window or self.
  3. window.parent -> returns the parent frame of the current frame or iframe. The parent frame may be the frameset window or another frame if you have nested frames. If not using frames, parent is the same as the current window or self

Centering the pagination in bootstrap

Using laravel with bootstrap 4, the solution that worked:

<div class="d-flex">
    <div class="mx-auto">

How to disable compiler optimizations in gcc?

The gcc option -O enables different levels of optimization. Use -O0 to disable them and use -S to output assembly. -O3 is the highest level of optimization.

Starting with gcc 4.8 the optimization level -Og is available. It enables optimizations that do not interfere with debugging and is the recommended default for the standard edit-compile-debug cycle.

To change the dialect of the assembly to either intel or att use -masm=intel or -masm=att.

You can also enable certain optimizations manually with -fname.

Have a look at the gcc manual for much more.

CSS grid wrapping

Here's my attempt. Excuse the fluff, I was feeling extra creative.

My method is a parent div with fixed dimensions. The rest is just fitting the content inside that div accordingly.

This will rescale the images regardless of the aspect ratio. There will be no hard cropping either.

body {_x000D_
    background: #131418;_x000D_
    text-align: center;_x000D_
    margin: 0 auto;_x000D_
.my-image-parent {_x000D_
    display: inline-block;_x000D_
    width: 300px;_x000D_
    height: 300px;_x000D_
    line-height: 300px; /* Should match your div height */_x000D_
    text-align: center;_x000D_
    font-size: 0;_x000D_
/* Start demonstration background fluff */_x000D_
    .bg1 {background: url(;}_x000D_
    .bg2 {background: url(;}_x000D_
    .bg3 {background: url(;}_x000D_
    .bg4 {background: url(;}_x000D_
    .bg5 {background: url(;}_x000D_
    .bg6 {background: url(;}_x000D_
    .bg7 {background: url(;}_x000D_
    .bg8 {background: url(;}_x000D_
    .bg9 {background: url(;}_x000D_
    .bg10 {background: url(;}_x000D_
    .bg11 {background: url(;}_x000D_
    .bg12 {background: url(;}_x000D_
    .bg13 {background: url(;}_x000D_
    .bg14 {background: url(;}_x000D_
    .bg15 {background: url(;}_x000D_
    .bg16 {background: url(;}_x000D_
    .bg17 {background: url(;}_x000D_
    .bg18 {background: url(;}_x000D_
    .bg19 {background: url(;}_x000D_
    .bg20 {background: url(;}_x000D_
/* end demonstration background fluff */_x000D_
.my-image {_x000D_
    width: auto;_x000D_
    height: 100%;_x000D_
    vertical-align: middle;_x000D_
    background-size: contain;_x000D_
    background-position: center;_x000D_
    background-repeat: no-repeat;_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg1"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg2"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg3"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg4"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg5"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg6"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg7"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg8"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg9"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg10"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg11"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg12"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg13"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg14"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg15"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg16"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg17"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg18"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg19"></div>_x000D_
<div class="my-image-parent">_x000D_
    <div class="my-image bg20"></div>_x000D_

How can I view the Git history in Visual Studio Code?

It is evident to me that GitLens is the most popular extension for Git history.

enter image description here

What I like the most it can provide you side annotations when some line has been changed the last time and by whom.

Enter image description here

How do I replicate a \t tab space in HTML?

You can use this &emsp; or &ensp;

It works on Visual Studio

How to get the public IP address of a user in C#

 private string GetClientIpaddress()
        string ipAddress = string.Empty;
        ipAddress = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
        if (ipAddress == "" || ipAddress == null)
            ipAddress = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
            return ipAddress;
            return ipAddress;

What are best practices for REST nested resources?

I disagree with this kind of path

GET /companies/{companyId}/departments

If you want to get departments, I think it's better to use a /departments resource

GET /departments?companyId=123

I suppose you have a companies table and a departments table then classes to map them in the programming language you use. I also assume that departments could be attached to other entities than companies, so a /departments resource is straightforward, it's convenient to have resources mapped to tables and also you don't need as many endpoints since you can reuse

GET /departments?companyId=123

for any kind of search, for instance

GET /departments?name=xxx
GET /departments?companyId=123&name=xxx

If you want to create a department, the

POST /departments

resource should be used and the request body should contain the company ID (if the department can be linked to only one company).

Displaying unicode symbols in HTML

You should ensure the HTTP server headers are correct.

In particular, the header:

Content-Type: text/html; charset=utf-8

should be present.

The meta tag is ignored by browsers if the HTTP header is present.

Also ensure that your file is actually encoded as UTF-8 before serving it, check/try the following:

  • Ensure your editor save it as UTF-8.
  • Ensure your FTP or any file transfer program does not mess with the file.
  • Try with HTML encoded entities, like &#uuu;.
  • To be really sure, hexdump the file and look as the character, for the ?, it should be E2 9C 94 .

Note: If you use an unicode character for which your system can't find a glyph (no font with that character), your browser should display a question mark or some block like symbol. But if you see multiple roman characters like you do, this denotes an encoding problem.

Call to undefined method mysqli_stmt::get_result

Here is my alternative. It is object-oriented and is more like mysql/mysqli things.

class MMySqliStmt{
    private $stmt;
    private $row;

    public function __construct($stmt){
        $this->stmt = $stmt;
        $md = $stmt->result_metadata();
        $params = array();
        while($field = $md->fetch_field()) {
            $params[] = &$this->row[$field->name];
        call_user_func_array(array($stmt, 'bind_result'), $params) or die('Sql Error');

    public function fetch_array(){
            $result = array();
            foreach($this->row as $k => $v){
                $result[$k] = $v;
            return $result;
            return false;

    public function free(){


$stmt = $conn->prepare($str);
//...bind_param... and so on
if(!$stmt->execute())die('Mysql Query(Execute) Error : '.$str);
$result = new MMySqliStmt($stmt);
while($row = $result->fetch_array()){
    array_push($arr, $row);
    //for example, use $row['id']
//for example, use the $arr

When is JavaScript synchronous?

To someone who really understands how JS works this question might seem off, however most people who use JS do not have such a deep level of insight (and don't necessarily need it) and to them this is a fairly confusing point, I will try to answer from that perspective.

JS is synchronous in the way its code is executed. each line only runs after the line before it has completed and if that line calls a function after that is complete etc...

The main point of confusion arises from the fact that your browser is able to tell JS to execute more code at anytime (similar to how you can execute more JS code on a page from the console). As an example JS has Callback functions who's purpose is to allow JS to BEHAVE asynchronously so further parts of JS can run while waiting for a JS function that has been executed (I.E. a GET call) to return back an answer, JS will continue to run until the browser has an answer at that point the event loop (browser) will execute the JS code that calls the callback function.

Since the event loop (browser) can input more JS to be executed at any point in that sense JS is asynchronous (the primary things that will cause a browser to input JS code are timeouts, callbacks and events)

I hope this is clear enough to be helpful to somebody.

app.config for a class library

You do want to add App.config to your tests class library, if you're using a tracer/logger. Otherwise nothing gets logged when you run the test through a test runner such as TestDriven.Net.

For example, I use TraceSource in my programs, but running tests doesn't log anything unless I add an App.config file with the trace/log configuration to the test class library too.

Otherwise, adding App.config to a class library doesn't do anything.

How to write a SQL DELETE statement with a SELECT statement in the WHERE clause?

in this scenario:

WHERE (SELECT q.entitynum
FROM tableA q
INNER JOIN tableB u on (u.qlabel = q.entityrole AND u.fieldnum = q.fieldnum) 
WHERE (LENGTH(q.memotext) NOT IN (8,9,10) 
OR q.memotext NOT LIKE '%/%/%')
AND (u.FldFormat = 'Date'));

aren't you missing the column you want to compare to? example:

WHERE entitynum in (SELECT q.entitynum
FROM tableA q
INNER JOIN tableB u on (u.qlabel = q.entityrole AND u.fieldnum = q.fieldnum) 
WHERE (LENGTH(q.memotext) NOT IN (8,9,10) 
OR q.memotext NOT LIKE '%/%/%')
AND (u.FldFormat = 'Date'));    

I assume it's that column since in your select statement you're selecting from the same table you're wanting to delete from with that column.

Unicode characters in URLs

For me this is the correct way, This just worked:

    $linker = rawurldecode("$link");
    <a href="<?php echo $link;?>"   target="_blank"><?php echo $linker ;?></a>

This worked, and now links are displayed properly:

Link found on:

JQuery or JavaScript: How determine if shift key being pressed while clicking anchor tag hyperlink?

The keypress event isn't triggered by all browsers when you click shift or ctrl, but fortunately the keydown event is.

If you switch out the keypress with keydown you might have better luck.

How to really read text file from classpath in Java

you have to put your 'system variable' on the java classpath.

How to "flatten" a multi-dimensional array to simple one in PHP?

any of this didnt work for me ... so had to run it myself. works just fine:

function arrayFlat($arr){
$out = '';
    foreach($arr as $key => $value){

            $out .= $value.',';
            $out .= $key.',';
            $out .= arrayFlat($value);

    return trim($out,',');

$result = explode(',',arrayFlat($yourArray));
echo '<pre>';
echo '</pre>';

How to access share folder in virtualbox. Host Win7, Guest Fedora 16?

This thread has some great tips. However....

@GirishB's answer isn't correct - sorry. Jartender's is best.

Also, every post in here seems to assume you're logging in to the Linux guest as root, except for @tomoguisuru. Yuck! Don't use root, use a separate user account and "sudo" when you need root privileges. Then this user (or any other user who needs the shared folder) should have membership in the vboxsf group, and @tomoguisuru's command is perfect, even terser than what I use.

Forget running mount yourself. Set up the shared folder to auto mount and you'll find the shared folder - it's under /media in my OEL (RH and Centos probably the same). If it's not there, just run "mount" with no arguments and look for the mounted directory of type vboxsf.

Terminal showing 'mount' and where to find mounted shared folder

How do I add a newline to a TextView in Android?

You need to put \n in the file string.xml

<string name="strtextparkcar">press Park my Car to store location \n</string>

Cookies on localhost with explicit domain

There seems to be an issue when you use https://<local-domain> and then http://<local-domain>. The http:// site does not send cookies with requests after https:// site sets them. Force reload and clear cache doesn't help. Only manual clearing of cookies works. Also, if I clear them on the https:// page, then http:// page starts working again.

Looks to be related to "Strict secure cookies". Good explanation here. It was released in Chrome 58 on 2017-04-19.

It looks like Chrome does in fact record both secure cookies and non-secure cookies as it will show the correct cookies depending on the page's protocol when clicking the address bar icon.

But Developer tools > Application > Cookies will not show a non-secure cookie when there is a secure cookie of the same name for the same domain, nor will it send the non-secure cookie with any requests. This seems like a Chrome bug, or if this behavior is expected, there should be some way to view the secure cookies when on a http page and an indication that they are being overridden.

Workaround is to use different named cookies depending on if they are for an http site or https site, and to name them specific to your app. A __Secure- prefix indicates that the cookie should be strictly secure, and is also a good practice because secure and non-secure won't collide. There are other benefits to prefixes too.

Using different /etc/hosts domains for https vs. http access would work too, but one accidental https://localhost visit will prevent any cookies of the same names to work on http://localhost sites - so this is not a good workaround.

I have filed a Chrome bug report.

Simple way to unzip a .zip file using zlib

zlib handles the deflate compression/decompression algorithm, but there is more than that in a ZIP file.

You can try libzip. It is free, portable and easy to use.

UPDATE: Here I attach quick'n'dirty example of libzip, with all the error controls ommited:

#include <zip.h>

int main()
    //Open the ZIP archive
    int err = 0;
    zip *z = zip_open("", 0, &err);

    //Search for the file of given name
    const char *name = "file.txt";
    struct zip_stat st;
    zip_stat(z, name, 0, &st);

    //Alloc memory for its uncompressed contents
    char *contents = new char[st.size];

    //Read the compressed file
    zip_file *f = zip_fopen(z, name, 0);
    zip_fread(f, contents, st.size);

    //And close the archive

    //Do something with the contents
    //delete allocated memory
    delete[] contents;

How to download Visual Studio Community Edition 2015 (not 2017)

The "official" way to get the vs2015 is to go to ; join the " Visual Studio Dev Essentials" and then search the relevant file to download

Reversing an Array in Java

You could use org.apache.commons.lang.ArrayUtils : ArrayUtils.reverse(array)

Nginx: Permission denied for nginx on Ubuntu

if you don't want to start nginx as root.

first creat log file :

sudo touch /var/log/nginx/error.log

and then fix permissions:

sudo chown -R www-data:www-data /var/log/nginx

sudo find /var/log/nginx -type f -exec chmod 666 {} \;

sudo find /var/log/nginx -type d -exec chmod 755 {} \;

Can I concatenate multiple MySQL rows into one field?

Have a look at GROUP_CONCAT if your MySQL version (4.1) supports it. See the documentation for more details.

It would look something like:

  FROM peoples_hobbies 
  WHERE person_id = 5 
  GROUP BY 'all';

Iterating through a list to render multiple widgets in Flutter?

when you return some thing, the code exits out of the loop with what ever you are, in your code, in the first iteration, name is "one". so, as soon as it reaches return new Text(name), code exits the loop with return new Text("one"). so, try to print it or use asynchronous returns.

HTML Input Type Date, Open Calendar by default

This is not possible with native HTML input elements. You can use webshim polyfill, which gives you this option by using this markup.

<input type="date" data-date-inline-picker="true" />

Here is a small demo

How to move files from one git repo to another (not a clone), preserving history

In my case, I didn't need to preserve the repo I was migrating from or preserve any previous history. I had a patch of the same branch, from a different remote

#Source directory
git remote rm origin
#Target directory
git remote add branch-name-from-old-repo ../source_directory

In those two steps, I was able to get the other repo's branch to appear in the same repo.

Finally, I set this branch (that I imported from the other repo) to follow the target repo's mainline (so I could diff them accurately)

git br --set-upstream-to=origin/mainline

Now it behaved as-if it was just another branch I had pushed against that same repo.

How do I get currency exchange rates via an API such as Google Finance?

For all newbie guys searching for some hint about currency conversion, take a look at this link. Datavoila

It helped med a lot regarding my own project in C#. Just in case the site disappears, I'll add the code below. Just add the below steps to your own project. Sorry about the formatting.

const string fromCurrency = "USD";
const string toCurrency = "EUR";
const double amount = 49.95;
// For other currency symbols see
// Clear the output editor //optional use, AFAIK

// Construct URL to query the Yahoo! Finance API
const string urlPattern = "{0}{1}=X&f=l1";
string url = String.Format(urlPattern, fromCurrency, toCurrency);

// Get response as string
string response = new WebClient().DownloadString(url);

// Convert string to number
double exchangeRate =
    double.Parse(response, System.Globalization.CultureInfo.InvariantCulture);

// Output the result
Output.Text = String.Format("{0} {1} = {2} {3}",
                            amount, fromCurrency,
                            amount * exchangeRate, toCurrency);

How do I enable php to work with postgresql?

I installed PHP on windows IIS using Windows Platform Installer (WP?). WP? creates a "PHP Manager" tool in "Internet Information Services (IIS) Manager" console. I am configuring PHP using this tool.

in says:

PDO and all the major drivers ship with PHP as shared extensions, and simply need to be activated by editing the php.ini file: extension=php_pdo.dll

so i activated the extension using PHP Manager and now PDO works fine

PHP manager simple added the following two lines in my php.ini, you can add the lines by hand. Of course you must restart the web server.


How to increase font size in NeatBeans IDE?

press alt and scroll down or up to change the size

Why is volatile needed in C?

A volatile can be changed from outside the compiled code (for example, a program may map a volatile variable to a memory mapped register.) The compiler won't apply certain optimizations to code that handles a volatile variable - for example, it won't load it into a register without writing it to memory. This is important when dealing with hardware registers.