Programs & Examples On #Clienthttpstack

ubuntu "No space left on device" but there is tons of space

It's possible that you've run out of memory or some space elsewhere and it prompted the system to mount an overflow filesystem, and for whatever reason, it's not going away.

Try unmounting the overflow partition:

umount /tmp


umount overflow

Replace contents of factor column in R dataframe

You want to replace the values in a dataset column, but you're getting an error like this:

invalid factor level, NA generated

Try this instead:

levels(dataframe$column)[levels(dataframe$column)=='old_value'] <- 'new_value'

trigger body click with jQuery

Interestingly, when I replaced this:


With this:


It works!

SmartGit Installation and Usage on Ubuntu

What it correct way of installing SmartGit on Ubuntu? Thus I can have normal icon

In smartgit/bin folder, there's a shell script waiting for you: It does just that.

Why doesn't Java offer operator overloading?

Some people say that operator overloading in Java would lead to obsfuscation. Have those people ever stopped to look at some Java code doing some basic maths like increasing a financial value by a percentage using BigDecimal ? .... the verbosity of such an exercise becomes its own demonstration of obsfuscation. Ironically, adding operator overloading to Java would allow us to create our own Currency class which would make such mathematical code elegant and simple (less obsfuscated).

Get Country of IP Address with PHP provides a scalable API to do this. With 10 global endpoints each able to handle >800M requests daily!

It also gives you the organisation, currency, timezone, calling code, flag and Tor Exit Node status data from any IPv4 or IPv6 address.

In php

php > $ip = '';
php > $details = json_decode(file_get_contents("{$ip}"));
php > echo $details->region;
php > echo $details->city;
Mountain View
php > echo $details->country_name;
United States
php > echo $details->location;


I built this service.

How to correctly iterate through getElementsByClassName

If you use the new querySelectorAll you can call forEach directly.

document.querySelectorAll('.edit').forEach(function(button) {
    // Now do something with my button

Per the comment below. nodeLists do not have a forEach function.

If using this with babel you can add Array.from and it will convert non node lists to a forEach array. Array.from does not work natively in browsers below and including IE 11.

Array.from(document.querySelectorAll('.edit')).forEach(function(button) {
    // Now do something with my button

At our meetup last night I discovered another way to handle node lists not having forEach

[...document.querySelectorAll('.edit')].forEach(function(button) {
    // Now do something with my button

Browser Support for [...]

Showing as Node List

Showing as Node List

Showing as Array

Showing as Array

elasticsearch bool query combine must with OR

This is how you can nest multiple bool queries in one outer bool query this using Kibana,

  • bool indicates we are using boolean
  • must is for AND
  • should is for OR
GET my_inedx/my_type/_search
  "query" : {
     "bool": {             //bool indicates we are using boolean operator
          "must" : [       //must is for **AND**
                 "match" : {
                       "description" : "some text"  
                  "match" :{
                        "type" : "some Type"
                  "bool" : {          //here its a nested boolean query
                        "should" : [  //should is for **OR**
                                 "match" : {
                                     //ur query
                                  "match" : {} 

This is how you can nest a query in ES

There are more types in "bool" like,

  1. Filter
  2. must_not

error: expected class-name before ‘{’ token


#include "Landing.h"


class Landing;

If you still get errors, also post Item.h, Flight.h and common.h

EDIT: In response to comment.

You will need to e.g. #include "Landing.h" from Event.cpp in order to actually use the class. You just cannot include it from Event.h

Gray out image with CSS?

Use the CSS3 filter property:

img {
    -webkit-filter: grayscale(100%);
       -moz-filter: grayscale(100%);
         -o-filter: grayscale(100%);
        -ms-filter: grayscale(100%);
            filter: grayscale(100%); 

The browser support is a little bad but it's 100% CSS. A nice article about the CSS3 filter property you can find here:

Search and replace a particular string in a file using Perl

A one liner:

perl -pi.back -e 's/<PREF>/ABCD/g;' inputfile

How to set encoding in .getJSON jQuery

Use encodeURI() in client JS and use URLDecoder.decode() in server Java side works.


  • Javascript:

            "user": encodeURI(JSON.stringify(user))
  • Java:, "UTF-8");

Comparing date part only without comparing time in JavaScript

Just use toDateString() on both dates. toDateString doesn't include the time, so for 2 times on the same date, the values will be equal, as demonstrated below.

var d1 = new Date(2019,01,01,1,20)
var d2 = new Date(2019,01,01,2,20)
console.log(d1==d2) // false
console.log(d1.toDateString() == d2.toDateString()) // true

Obviously some of the timezone concerns expressed elsewhere on this question are valid, but in many scenarios, those are not relevant.

Break or return from Java 8 stream forEach?

What about this one:

final BooleanWrapper condition = new BooleanWrapper();
someObjects.forEach(obj -> {
   if (condition.ok()) {
     // YOUR CODE to control

Where BooleanWrapper is a class you must implement to control the flow.

how to resolve DTS_E_OLEDBERROR. in ssis

I had a similar issue with my OLE DB Command and I resolved it by setting the ValidateExternalMetadata property within the component to False.

how to find array size in angularjs

You can find the number of members in a Javascript array by using its length property:

var number = $scope.names.length;

Docs - Array.prototype.length

What Language is Used To Develop Using Unity

Unity3d supports C#, Boo and JavaScript. The framework translates this into its intermediate format and later to the desired platform (IOS/Android/Linux/Windows)

Keep in mind, C# Scripts are compiled first, followed by JS and Boo Hence if you want a C# script to interact with a JS, you ll have to keep the JS in the Standard Assets Folder.

How to pass multiple parameters in thread in VB

Dim evaluator As New Thread(Sub() Me.testthread(goodList, 1))
With evaluator
.IsBackground = True ' not necessary...
End With

Where are SQL Server connection attempts logged?

You can enable connection logging. For SQL Server 2008, you can enable Login Auditing. In SQL Server Management Studio, open SQL Server Properties > Security > Login Auditing select "Both failed and successful logins".

Make sure to restart the SQL Server service.

Once you've done that, connection attempts should be logged into SQL's error log. The physical logs location can be determined here.

how to add value to combobox item

Now you can use insert method instead add

' Visual Basic
CheckedListBox1.Items.Insert(0, "Copenhagen")

HtmlSpecialChars equivalent in Javascript?

There is a problem with your solution code--it will only escape the first occurrence of each special character. For example:

escapeHtml('Kip\'s <b>evil</b> "test" code\'s here');
Actual:   Kip&#039;s &lt;b&gt;evil</b> &quot;test" code's here
Expected: Kip&#039;s &lt;b&gt;evil&lt;/b&gt; &quot;test&quot; code&#039;s here

Here is code that works properly:

function escapeHtml(text) {
  return text
      .replace(/&/g, "&amp;")
      .replace(/</g, "&lt;")
      .replace(/>/g, "&gt;")
      .replace(/"/g, "&quot;")
      .replace(/'/g, "&#039;");


The following code will produce identical results to the above, but it performs better, particularly on large blocks of text (thanks jbo5112).

function escapeHtml(text) {
  var map = {
    '&': '&amp;',
    '<': '&lt;',
    '>': '&gt;',
    '"': '&quot;',
    "'": '&#039;'
  return text.replace(/[&<>"']/g, function(m) { return map[m]; });

How Can I Set the Default Value of a Timestamp Column to the Current Timestamp with Laravel Migrations?

In laravel 7, to set current time use following:


grep's at sign caught as whitespace

No -P needed; -E is sufficient:

grep -E '(^|\s)abc(\s|$)' 

or even without -E:

grep '\(^\|\s\)abc\(\s\|$\)' 

Sql script to find invalid email addresses

On sql server 2016 and up

 @EmailAddr varchar(360) -- Email address to check
)   RETURNS BIT -- 1 if @EmailAddr is a valid email address

DECLARE @AlphabetPlus VARCHAR(255)
      , @Max INT -- Length of the address
      , @Pos INT -- Position in @EmailAddr
      , @OK BIT  -- Is @EmailAddr OK
-- Check basic conditions
IF @EmailAddr IS NULL 
   OR @EmailAddr NOT LIKE '[0-9a-zA-Z]%@__%.__%' 
   OR @EmailAddr LIKE '%@%@%' 
   OR @EmailAddr LIKE '%..%' 
   OR @EmailAddr LIKE '%.@' 
   OR @EmailAddr LIKE '%@.' 
   OR @EmailAddr LIKE '%@%.-%' 
   OR @EmailAddr LIKE '%@%-.%' 
   OR @EmailAddr LIKE '%@-%' 
   OR CHARINDEX(' ',LTRIM(RTRIM(@EmailAddr))) > 0

declare @AfterLastDot varchar(360);
declare @AfterArobase varchar(360);
declare @BeforeArobase varchar(360);
declare @HasDomainTooLong bit=0;

--Control des longueurs et autres incoherence
set @AfterLastDot=REVERSE(SUBSTRING(REVERSE(@EmailAddr),0,CHARINDEX('.',REVERSE(@EmailAddr))));
if  len(@AfterLastDot) not between 2 and 17

set @AfterArobase=REVERSE(SUBSTRING(REVERSE(@EmailAddr),0,CHARINDEX('@',REVERSE(@EmailAddr))));
if len(@AfterArobase) not between 2 and 255

select top 1 @BeforeArobase=value from  string_split(@EmailAddr, '@');
if len(@AfterArobase) not between 2 and 255

--Controle sous-domain pas plus grand que 63
select top 1 @HasDomainTooLong=1 from string_split(@AfterArobase, '.') where LEN(value)>63
if @HasDomainTooLong=1

--Control de la partie locale en detail
SELECT @AlphabetPlus = 'abcdefghijklmnopqrstuvwxyz01234567890!#$%&‘*+-/=?^_`.{|}~'
     , @Max = LEN(@BeforeArobase)
     , @Pos = 0
     , @OK = 1

WHILE @Pos < @Max AND @OK = 1 BEGIN
    SET @Pos = @Pos + 1
    IF @AlphabetPlus NOT LIKE '%' + SUBSTRING(@BeforeArobase, @Pos, 1) + '%' 
        SET @OK = 0

if @OK=0

--Control de la partie domaine en detail
SELECT @AlphabetPlus = 'abcdefghijklmnopqrstuvwxyz01234567890-.'
     , @Max = LEN(@AfterArobase)
     , @Pos = 0
     , @OK = 1

WHILE @Pos < @Max AND @OK = 1 BEGIN
    SET @Pos = @Pos + 1
    IF @AlphabetPlus NOT LIKE '%' + SUBSTRING(@AfterArobase, @Pos, 1) + '%' 
        SET @OK = 0

if @OK=0



Pretty git branch graphs

Very slightly tweaking Slipp's awesome answer, you can use his aliases to log just one branch:

lgBranch1 = log --graph --format=format:'%C(bold blue)%h%C(reset) - %C(bold green)(%ar)%C(reset) %C(white)%s%C(reset) %C(bold white)— %an%C(reset)%C(bold yellow)%d%C(reset)' --abbrev-commit --date=relative
lgBranch2 = log --graph --format=format:'%C(bold blue)%h%C(reset) - %C(bold cyan)%aD%C(reset) %C(bold green)(%ar)%C(reset)%C(bold yellow)%d%C(reset)%n''          %C(white)%s%C(reset) %C(bold white)— %an%C(reset)' --abbrev-commit
lg = !"git lg1"

By leaving off the --all you can now do

git lgBranch1 <branch name>

or even

git lgBranch1 --all

GIT clone repo across local file system in windows

$ git clone --no-hardlinks /path/to/repo

The above command uses POSIX path notation for the directory with your git repository. For Windows it is (directory C:/path/to/repo contains .git directory):

C:\some\dir\> git clone --local file:///C:/path/to/repo my_project

The repository will be clone to C:\some\dir\my_project. If you omit file:/// part then --local option is implied.

Verify if file exists or not in C#

These answers all assume the file you are checking is on the server side. Unfortunately, there is no cast iron way to ensure that a file exists on the client side (e.g. if you are uploading the resume). Sure, you can do it in Javascript but you are still not going to be 100% sure on the server side.

The best way to handle this, in my opinion, is to assume that the user will actually select an appropriate file for upload, and then do whatever work you need to do to ensure the uploaded file is what you expect (hint - assume the user is trying to poison your system in every possible way with his/her input)

Bootstrap carousel width and height

I recommend the following for Bootstrap 3

.carousel-inner > .item > img,
.carousel-inner > .item > a > img {
  min-height: 500px;    /* Set slide height here */


Sum all values in every column of a data.frame in R

You can use function colSums() to calculate sum of all values. [,-1] ensures that first column with names of people is excluded.

Height Weight 
   199    425

Assuming there could be multiple columns that are not numeric, or that your column order is not fixed, a more general approach would be:

colSums(Filter(is.numeric, people))

PHPMailer AddAddress()

foreach ($all_address as $aa) {

Python MYSQL update statement

You've got the syntax all wrong:

cursor.execute ("""
   UPDATE tblTableName
   SET Year=%s, Month=%s, Day=%s, Hour=%s, Minute=%s
   WHERE Server=%s
""", (Year, Month, Day, Hour, Minute, ServerID))

For more, read the documentation.

Get image data url in JavaScript?

In HTML5 better use this:

canvas.width = img.naturalWidth; //img.width;
canvas.height = img.naturalHeight; //img.height;

Struct like objects in Java

By the way, the structure you're giving as an example already exist in the Java base class library as java.awt.Point. It has x and y as public fields, check it out for yourself.

If you know what you're doing, and others in your team know about it, then it is okay to have public fields. But you shouldn't rely on it because they can cause headaches as in bugs related to developers using objects as if they were stack allocated structs (java objects are always sent to methods as references and not as copies).

Java: Most efficient method to iterate over all elements in a org.w3c.dom.Document?

for (int i = 0; i < nodeList.getLength(); i++)

change to

for (int i = 0, len = nodeList.getLength(); i < len; i++)

to be more efficient.

The second way of javanna answer may be the best as it tends to use a flatter, predictable memory model.

Are email addresses case sensitive?

Way late to this post, but I've got something slightly different to say...

>> "Are email addresses case sensitive?"

Well, "It Depends..." (TM)

Some organizations actually think that's a good idea and their email servers enforce case sensitivity.

So, for those crazy places, "Yes, Emails are case sensitive."

Note: Just because a specification says you can do something does not mean it is a good idea to do so.

The principle of KISS suggests that our systems use case insensitive emails.

Whereas the Robustness principle suggests that we accept case sensitive emails.


  • Store emails with case sensitivity
  • Send emails with case sensitivity
  • Perform internal searches with case insensitivity

This would mean that if this email already exists: [email protected]

... and another user comes along and wants to use this email: [email protected]

... that our case insensitive searching logic would return a "That email already exists" error message.

Now, you have a decision to make: Is that solution adequate in your case?

If not, you could charge a convenience fee to those clients that demand support for their case sensitive emails and implement custom logic that allows the [email protected] into your system, even if [email protected] already exists.

In which case your email search/validation logic might look like something this pseudocode:

if (user.paidEmailFee) {
   // case sensitive email
   query = "select * from users where email LIKE ' + + '"
} else {
   // case insensitive email
   query = "select * from users where email ILIKE ' + + '"

This way, you are mostly enforcing case insensitivity but allowing customers to pay for this support if they are using email systems that support such nonsense.

p.s. ILIKE is a PostgreSQL keyword:

How to find the last day of the month from date?

    $startDate = '2011-12-01';
    $endDate = date('Y-m');
    while (true) {
        try {
            $startDateTime = new DateTime($startDate);
            $startDateTime->add(new DateInterval('P1M'));
            $startDate = $startDateTime->format('Y-m-d');
            $endTime = $startDateTime->format('Y-m-t');
            echo $startDate . ' => ' . $endTime . PHP_EOL;
            if ($startDateTime->format('Y-m') == $endDate) {
        } catch (Exception $exception) {

After testing many solutions, this works best for me.

matrix multiplication algorithm time complexity

In matrix multiplication there are 3 for loop, we are using since execution of each for loop requires time complexity O(n). So for three loops it becomes O(n^3)

How to set time to 24 hour format in Calendar

I am using fullcalendar on my project recently, I don't know what exact view effect you want to achieve, in my project I want to change the event time view from 12h format from

enter image description here

to 24h format.

enter image description here

If this is the effect you want to achieve, the solution below might help:

set timeFormat: 'H:mm'

Open file in a relative location in Python

Python just passes the filename you give it to the operating system, which opens it. If your operating system supports relative paths like main/2091/data.txt (hint: it does), then that will work fine.

You may find that the easiest way to answer a question like this is to try it and see what happens.

Passing an array of data as an input parameter to an Oracle procedure

If the types of the parameters are all the same (varchar2 for example), you can have a package like this which will do the following:


   TYPE assoc_array_varchar2_t IS TABLE OF VARCHAR2(4000) INDEX BY BINARY_INTEGER;

   PROCEDURE your_proc(p_parm IN assoc_array_varchar2_t);

END test_pkg;


   PROCEDURE your_proc(p_parm IN assoc_array_varchar2_t) AS
      FOR i IN p_parm.first .. p_parm.last
      END LOOP;


END test_pkg;

Then, to call it you'd need to set up the array and pass it:

  l_array testuser.test_pkg.assoc_array_varchar2_t;
  l_array(0) := 'hello';
  l_array(1) := 'there';  


How do I access an access array item by index in handlebars?

While you are looping in an array with each and if you want to access another array in the context of the current item you do it like this.

Here is the example data.

    name: 'foo',
    attr: [ 'boo', 'zoo' ]
    name: 'bar',
    attr: [ 'far', 'zar' ]

Here is the handlebars to get the first item in attr array.

{{#each player}}
  <p> {{}} </p>

  {{#with this.attr}}
    <p> {{this.[0]}} </p>


This will output

<p> foo </p>
<p> boo </p>

<p> bar </p>
<p> far </p>

Laravel Redirect Back with() Message

You have an error (misspelling):

Sessions::get('msg')// an extra 's' on end

Should be:


I think, now it should work, it does for me.

Using iFrames In ASP.NET

try this

<iframe name="myIframe" id="myIframe" width="400px" height="400px" runat="server"></iframe>

Expose this iframe in the master page's codebehind:

public HtmlControl iframe
return this.myIframe;

Add the MasterType directive for the content page to strongly typed Master Page.

<%@ Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits=_Default" Title="Untitled Page" %>
<%@ MasterType VirtualPath="~/MasterPage.master" %>

In code behind

protected void Page_Load(object sender, EventArgs e)
this.Master.iframe.Attributes.Add("src", "some.aspx");

How to detect when an Android app goes to the background and come back to the foreground

Consider using onUserLeaveHint. This will only be called when your app goes into the background. onPause will have corner cases to handle, since it can be called for other reasons; for example if the user opens another activity in your app such as your settings page, your main activity's onPause method will be called even though they are still in your app; tracking what is going in will lead to bugs when you can instead simply use the onUserLeaveHint callback which does what you are asking.

When on UserLeaveHint is called, you can set a boolean inBackground flag to true. When onResume is called, only assume you came back into the foreground if the inBackground flag is set. This is because onResume will also be called on your main activity if the user was just in your settings menu and never left the app.

Remember that if the user hits the home button while in your settings screen, onUserLeaveHint will be called in your settings activity, and when they return onResume will be called in your settings activity. If you only have this detection code in your main activity you will miss this use case. To have this code in all your activities without duplicating code, have an abstract activity class which extends Activity, and put your common code in it. Then each activity you have can extend this abstract activity.

For example:

public abstract AbstractActivity extends Activity {
    private static boolean inBackground = false;

    public void onResume() {
        if (inBackground) {
            // You just came from the background
            inBackground = false;
        else {
            // You just returned from another activity within your own app

    public void onUserLeaveHint() {
        inBackground = true;

public abstract MainActivity extends AbstractActivity {

public abstract SettingsActivity extends AbstractActivity {

Implicit type conversion rules in C++ operators

Arithmetic operations involving float results in float.

int + float = float
int * float = float
float * int = float
int / float = float
float / int = float
int / int = int

For more detail answer. Look at what the section §5/9 from the C++ Standard says

Many binary operators that expect operands of arithmetic or enumeration type cause conversions and yield result types in a similar way. The purpose is to yield a common type, which is also the type of the result.

This pattern is called the usual arithmetic conversions, which are defined as follows:

— If either operand is of type long double, the other shall be converted to long double.

— Otherwise, if either operand is double, the other shall be converted to double.

— Otherwise, if either operand is float, the other shall be converted to float.

— Otherwise, the integral promotions (4.5) shall be performed on both operands.54)

— Then, if either operand is unsigned long the other shall be converted to unsigned long.

— Otherwise, if one operand is a long int and the other unsigned int, then if a long int can represent all the values of an unsigned int, the unsigned int shall be converted to a long int; otherwise both operands shall be converted to unsigned long int.

— Otherwise, if either operand is long, the other shall be converted to long.

— Otherwise, if either operand is unsigned, the other shall be converted to unsigned.

[Note: otherwise, the only remaining case is that both operands are int ]

Find all paths between two graph nodes

The following functions (modified BFS with a recursive path-finding function between two nodes) will do the job for an acyclic graph:

from collections import defaultdict

# modified BFS
def find_all_parents(G, s):
    Q = [s]
    parents = defaultdict(set)
    while len(Q) != 0:
        v = Q[0]
        for w in G.get(v, []):
    return parents

# recursive path-finding function (assumes that there exists a path in G from a to b)   
def find_all_paths(parents, a, b): 
    return [a] if a == b else [y + b for x in list(parents[b]) for y in find_all_paths(parents, a, x)]

For example, with the following graph (DAG) G given by

G = {'A':['B','C'], 'B':['D'], 'C':['D', 'F'], 'D':['E', 'F'], 'E':['F']}

if we want to find all paths between the nodes 'A' and 'F' (using the above-defined functions as find_all_paths(find_all_parents(G, 'A'), 'A', 'F')), it will return the following paths:

enter image description here

How to retrieve unique count of a field using Kibana + Elastic Search

Create "topN" query on "clientip" and then histogram with count on "clientip" and set "topN" query as source. Then you will see count of different ips per time.

How do you perform a left outer join using linq extension methods

Improving on Ocelot20's answer, if you have a table you're left outer joining with where you just want 0 or 1 rows out of it, but it could have multiple, you need to Order your joined table:

var qry = Foos.GroupJoin(
      Bars.OrderByDescending(b => b.Id),
      foo => foo.Foo_Id,
      bar => bar.Foo_Id,
      (f, bs) => new { Foo = f, Bar = bs.FirstOrDefault() });

Otherwise which row you get in the join is going to be random (or more specifically, whichever the db happens to find first).

How to get ER model of database from server with Workbench

  1. Go to "Database" Menu option
  2. Select the "Reverse Engineer" option.
  3. A wizard will be open and it will generate the ER Diagram for you.

Using DateTime in a SqlParameter for Stored Procedure, format error

Just use:


That will take care of all your problems.

What does android:layout_weight mean?

layout_weight defines how much space the control must obtain respectively to other controls.

Removing duplicate rows from table in Oracle

create table abcd(id number(10),name varchar2(20))

insert into abcd values(1,'abc')

insert into abcd values(2,'pqr')

insert into abcd values(3,'xyz')

insert into abcd values(1,'abc')

insert into abcd values(2,'pqr')

insert into abcd values(3,'xyz')

select * from abcd
id  Name
1   abc
2   pqr
3   xyz
1   abc
2   pqr
3   xyz

Delete Duplicate record but keep Distinct Record in table 

FROM abcd a

run the above query 3 rows delete 

select * from abcd

id  Name 
1   abc
2   pqr
3   xyz

Add 10 seconds to a Date

// let timeObject = new Date();
// let milliseconds= 10 * 1000; // 10 seconds = 10000 milliseconds
timeObject = new Date(timeObject.getTime() + milliseconds);

What is a LAMP stack?

I’ll try to answer the actual question of what a stack is.

In the Internet architecture (TCP/IP, OSI, etc.), protocols and software are often “stacked” on top of each other, as they depend on each other for support. For example, TCP provides reliable transmissions of data, on top of IP. The same goes for LAMP, your Apache server needs to run “on top of Linux”. Think of this “stack” as your favorite stack of pancakes, where each pancake is a different layer.

LAMP pancake stack


Eclipse Java Missing required source folder: 'src'

One of the build path issue is it cannot find the correct /src/conf source folder. Right click on each project, Build Path > Configure Build Path. Under the Source tab, remove the folder with a red cross icon on the bottom right. It will work for the situation that there is a small red exclamation mark “!“ bedore your project name!

Download & Install Xcode version without Premium Developer Account

You can download Xcode with/without Paid (Premium) Apple Developer Account from below links.

Xcode 11

Xcode 10

For non-premium account/apple id: (Download Xcode 10 without Paid (Premium) Apple Developer Account from below link)

Apple Download Portal

Look at here: How to install & set command line tool

See here for older versions of Xcode (Which may need to authenticate your apple account):

JQuery $.each() JSON array object iteration

Assign the second variable for the $.each function() as well, makes it lot easier as it'll provide you the data (so you won't have to work with the indicies).

$.each(json, function(arrayID,group) {
            console.log('<a href="'+group.GROUP_ID+'">');
    $.each(group.EVENTS, function(eventID,eventData) {

Should print out everything you were trying in your question.

edit renamed the variables to make it bit easier to understand what is what.

How to remove text from a string?

Another way to replace all instances of a string is to use the new (as of August 2020) String.prototype.replaceAll() method.

It accepts either a string or RegEx as its first argument, and replaces all matches found with its second parameter, either a string or a function to generate the string.

As far as support goes, at time of writing, this method has adoption in current versions of all major desktop browsers* (even Opera!), except IE. For mobile, iOS SafariiOS 13.7+, Android Chromev85+, and Android Firefoxv79+ are all supported as well.

* This includes Edge/ Chrome v85+, Firefox v77+, Safari 13.1+, and Opera v71+

It'll take time for users to update to supported browser versions, but now that there's wide browser support, time is the only obstacle.


You can test your current browser in the snippet below:

//Example coutesy of MDN:
const p = 'The quick brown fox jumps over the lazy dog. If the dog reacted, was it really lazy?';

const regex = /dog/gi;

try {
  console.log(p.replaceAll(regex, 'ferret'));
  // expected output: "The quick brown fox jumps over the lazy ferret. If the ferret reacted, was it really lazy?"

  console.log(p.replaceAll('dog', 'monkey'));
  // expected output: "The quick brown fox jumps over the lazy monkey. If the monkey reacted, was it really lazy?"
  console.log('Your browser is supported!');
} catch (e) {
  console.log('Your browser is unsupported! :(');
.as-console-wrapper: {
  max-height: 100% !important;

How to add items to array in nodejs

Here is example which can give you some hints to iterate through existing array and add items to new array. I use UnderscoreJS Module to use as my utility file.

You can download from (

$ npm install underscore

Here is small snippet to demonstrate how you can do it.

var _ = require("underscore");
var calendars = [1, "String", {}, 1.1, true],
    newArray = [];

_.each(calendars, function (item, index) {


Eclipse: Enable autocomplete / content assist

For auto-completion triggers in Eclipse like IntelliJ, follow these steps,

  1. Go to the Eclipse Windows menu -> Preferences -> Java -> Editor -> Content assist and check your settings here
  2. Enter in Autocomplete activation string for java: abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ._@
  3. Apply and Close the Dialog box.


OpenSSL Command to check if a server is presenting a certificate

In my case the ssl certificate was not configured for all sites (only for the www version which the non-www version redirected to). I am using Laravel forge and the Nginx Boilerplate config

I had the following config for my nginx site:


server {
    listen [::]:80;
    listen 80;

    include h5bp/directive-only/ssl.conf;

    # and redirect to the https host (declared below)
    # avoiding http://www -> https://www -> https:// chain.
    return 301$request_uri;

server {
    listen [::]:443 ssl spdy;
    listen 443 ssl spdy;

    # listen on the wrong host

    ### ERROR IS HERE ###
    # You eighter have to include the .crt and .key here also (like below)
    # or include it in the below included ssl.conf like suggested by H5BP

    include h5bp/directive-only/ssl.conf;

    # and redirect to the www host (declared below)
    return 301$request_uri;

server {
    listen [::]:443 ssl spdy;
    listen 443 ssl spdy;


    include h5bp/directive-only/ssl.conf;

    # Path for static files
    root /home/forge/default/public;

    ssl_certificate /etc/nginx/ssl/default/2658/server.crt;
    ssl_certificate_key /etc/nginx/ssl/default/2658/server.key;

    # ...

    # Include the basic h5bp config set
    include h5bp/basic.conf;

So after moving (cutting & pasting) the following part to the /etc/nginx/h5bp/directive-only/ssl.conf file everything worked as expected:

ssl_certificate /etc/nginx/ssl/default/2658/server.crt;
ssl_certificate_key /etc/nginx/ssl/default/2658/server.key;

So it is not enough to have the keys specified only for the www version even, if you only call the www version directly!

css label width not taking effect

Use display: inline-block;


The label is an inline element, meaning it is only as big as it needs to be.

Set the display property to either inline-block or block in order for the width property to take effect.


#report-upload-form {_x000D_
    background-color: #316091;_x000D_
    color: #ddeff1;_x000D_
    font-weight: bold;_x000D_
    margin: 23px auto 0 auto;_x000D_
    border-radius: 10px;_x000D_
    width: 650px;_x000D_
    box-shadow: 0 0 2px 2px #d9d9d9;_x000D_
#report-upload-form label {_x000D_
    padding-left: 26px;_x000D_
    width: 125px;_x000D_
    text-transform: uppercase;_x000D_
    display: inline-block;_x000D_
#report-upload-form input[type=text], _x000D_
#report-upload-form input[type=file],_x000D_
#report-upload-form textarea {_x000D_
    width: 305px;_x000D_
<form id="report-upload-form" method="POST" action="" enctype="multipart/form-data">_x000D_
    <p><label for="id_title">Title:</label> <input id="id_title" type="text" class="input-text" name="title"></p>_x000D_
    <p><label for="id_description">Description:</label> <textarea id="id_description" rows="10" cols="40" name="description"></textarea></p>_x000D_
    <p><label for="id_report">Upload Report:</label> <input id="id_report" type="file" class="input-file" name="report"></p>_x000D_

php hide ALL errors

In your php file just enter this code:


This will report no errors to the user. If you somehow want, then just comment this.

Should I initialize variable within constructor or outside constructor

Both the options can be correct depending on your situation.

A very simple example would be: If you have multiple constructors all of which initialize the variable the same way(int x=2 for each one of them). It makes sense to initialize the variable at declaration to avoid redundancy.

It also makes sense to consider final variables in such a situation. If you know what value a final variable will have at declaration, it makes sense to initialize it outside the constructors. However, if you want the users of your class to initialize the final variable through a constructor, delay the initialization until the constructor.

Why do we need boxing and unboxing in C#?

In .net, every instance of Object, or any type derived therefrom, includes a data structure which contains information about its type. "Real" value types in .net do not contain any such information. To allow data in value types to be manipulated by routines that expect to receive types derived from object, the system automatically defines for each value type a corresponding class type with the same members and fields. Boxing creates a new instances of this class type, copying the fields from a value type instance. Unboxing copies the fields from an instance of the class type to an instance of the value type. All of the class types which are created from value types are derived from the ironically named class ValueType (which, despite its name, is actually a reference type).

To compare two elements(string type) in XSLT?

First of all, the provided long code:

        <xsl:when test="OU_NAME='OU_ADDR1'">   --comparing two elements coming from XML             
            <!--remove if  adrees already contain  operating unit name <xsl:value-of select="OU_NAME"/> <fo:block/>-->
            <xsl:if test="OU_ADDR1 !='' ">
                <xsl:value-of select="OU_ADDR1"/>
            <xsl:if test="LE_ADDR2 !='' ">
                <xsl:value-of select="OU_ADDR2"/>
            <xsl:if test="LE_ADDR3 !='' ">
                <xsl:value-of select="OU_ADDR3"/>
            <xsl:if test="OU_TOWN_CITY !=''">
                <xsl:value-of select="OU_TOWN_CITY"/>,
                <fo:leader leader-pattern="space" leader-length="2.0pt"/>
            <xsl:value-of select="OU_REGION2"/>
            <fo:leader leader-pattern="space" leader-length="3.0pt"/>
            <xsl:value-of select="OU_POSTALCODE"/>
            <xsl:value-of select="OU_COUNTRY"/>
            <xsl:value-of select="OU_NAME"/>
            <xsl:if test="OU_ADDR1 !='' ">
                <xsl:value-of select="OU_ADDR1"/>
            <xsl:if test="LE_ADDR2 !='' ">
                <xsl:value-of select="OU_ADDR2"/>
            <xsl:if test="LE_ADDR3 !='' ">
                <xsl:value-of select="OU_ADDR3"/>
            <xsl:if test="OU_TOWN_CITY !=''">
                <xsl:value-of select="OU_TOWN_CITY"/>,
                <fo:leader leader-pattern="space" leader-length="2.0pt"/>
            <xsl:value-of select="OU_REGION2"/>
            <fo:leader leader-pattern="space" leader-length="3.0pt"/>
            <xsl:value-of select="OU_POSTALCODE"/>
            <xsl:value-of select="OU_COUNTRY"/>

is equivalent to this, much shorter code:

<xsl:if test="not(OU_NAME='OU_ADDR1)'">
              <xsl:value-of select="OU_NAME"/>
            <xsl:if test="OU_ADDR1 !='' ">
                <xsl:value-of select="OU_ADDR1"/>
            <xsl:if test="LE_ADDR2 !='' ">
                <xsl:value-of select="OU_ADDR2"/>
            <xsl:if test="LE_ADDR3 !='' ">
                <xsl:value-of select="OU_ADDR3"/>
            <xsl:if test="OU_TOWN_CITY !=''">
                <xsl:value-of select="OU_TOWN_CITY"/>,
                <fo:leader leader-pattern="space" leader-length="2.0pt"/>
            <xsl:value-of select="OU_REGION2"/>
            <fo:leader leader-pattern="space" leader-length="3.0pt"/>
            <xsl:value-of select="OU_POSTALCODE"/>
            <xsl:value-of select="OU_COUNTRY"/>

Now, to your question:

how to compare two elements coming from xml as string

In Xpath 1.0 strings can be compared only for equality (or inequality), using the operator = and the function not() together with the operator =.

$str1 = $str2

evaluates to true() exactly when the string $str1 is equal to the string $str2.

not($str1 = $str2)

evaluates to true() exactly when the string $str1 is not equal to the string $str2.

There is also the != operator. It generally should be avoided because it has anomalous behavior whenever one of its operands is a node-set.

Now, the rules for comparing two element nodes are similar:

$el1 = $el2

evaluates to true() exactly when the string value of $el1 is equal to the string value of $el2.

not($el1 = $el2)

evaluates to true() exactly when the string value of $el1 is not equal to the string value of $el2.

However, if one of the operands of = is a node-set, then

 $ns = $str

evaluates to true() exactly when there is at least one node in the node-set $ns1, whose string value is equal to the string $str

$ns1 = $ns2

evaluates to true() exactly when there is at least one node in the node-set $ns1, whose string value is equal to the string value of some node from $ns2

Therefore, the expression:


evaluates to true() only when there is at least one element child of the current node that is named OU_NAME and whose string value is the string 'OU_ADDR1'.

This is obviously not what you want!

Most probably you want:


This expression evaluates to true exactly there is at least one OU_NAME child of the current node and one OU_ADDR1 child of the current node with the same string value.

Finally, in XPath 2.0, strings can be compared also using the value comparison operators lt, le, eq, gt, ge and the inherited from XPath 1.0 general comparison operator =.

Trying to evaluate a value comparison operator when one or both of its arguments is a sequence of more than one item results in error.

How to vertically align a html radio button to it's label?

I know I'd selected the anwer by menuka devinda but looking at the comments below it I concurred and tried to come up with a better solution. I managed to come up with this and in my opinion it's a much more elegant solution:

input[type='radio'], label{   
    vertical-align: baseline;
    padding: 10px;
    margin: 10px;

Thanks to everyone who offered an answer, your answer didn't go unnoticed. If you still got any other ideas feel free to add your own answer to this question.

Fitting a histogram with python

Here you have an example working on py2.6 and py3.2:

from scipy.stats import norm
import matplotlib.mlab as mlab
import matplotlib.pyplot as plt

# read data from a text file. One number per line
arch = "test/Log(2)_ACRatio.txt"
datos = []
for item in open(arch,'r'):
    item = item.strip()
    if item != '':
        except ValueError:

# best fit of data
(mu, sigma) =

# the histogram of the data
n, bins, patches = plt.hist(datos, 60, normed=1, facecolor='green', alpha=0.75)

# add a 'best fit' line
y = mlab.normpdf( bins, mu, sigma)
l = plt.plot(bins, y, 'r--', linewidth=2)

plt.title(r'$\mathrm{Histogram\ of\ IQ:}\ \mu=%.3f,\ \sigma=%.3f$' %(mu, sigma))

enter image description here

java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/dbname

All of the answers here use the Class.forName("my.vandor.Driver"); line to load the driver.

As an (better) alternative you can use the DriverManager helper class which provides you with a handful of methods to handle your JDBC driver/s.

You might want to

  1. Use DriverManager.registerDriver(driverObject); to register your driver to it's list of drivers

Registers the given driver with the DriverManager. A newly-loaded driver class should call the method registerDriver to make itself known to the DriverManager. If the driver is currently registered, no action is taken

  1. Use DriverManager.deregisterDriver(driverObject); to remove it.

Removes the specified driver from the DriverManager's list of registered drivers.


Driver driver = new oracle.jdbc.OracleDriver();
Connection conn = DriverManager.getConnection(url, user, password);
// ... 
// and when you don't need anything else from the driver

or better yet, use a DataSource

How to read values from properties file?

Configure PropertyPlaceholder in your context:

<context:property-placeholder location="classpath*"/>

Then you refer to the properties in your beans:

class MyClass {
  private String[] myValues;

EDIT: updated the code to parse property with mutliple comma-separated values:,bbb,ccc

If that doesnt work, you can define a bean with properties, inject and process it manually:

<bean id="myProperties"
  <property name="locations">

and the bean:

class MyClass {
  private Properties myProperties;

  public void init() {
    // do whatever you need with properties

Open a link in browser with java button?

public static void openWebpage(String urlString) {
    try {
        Desktop.getDesktop().browse(new URL(urlString).toURI());
    } catch (Exception e) {

jQuery: Wait/Delay 1 second without executing code

JavaScript setTimeout is a very good solution:

function funcx()
   // your code here
   // break out here if needed
   setTimeout(funcx, 3000);


The delay function in jQuery is mostly used for delaying animations in a jQuery animation queue.

Is a URL allowed to contain a space?

Why does it have to be encoded? A request looks like this:

GET /url HTTP/1.1
(Ignoring headers)

There are 3 fields separated by a white space. If you put a space in your url:

GET /url end_url HTTP/1.1

You know have 4 fields, the HTTP server will tell you it is an invalid request.

GET /url%20end_url HTTP/1.1

3 fields => valid

Note: in the query string (after ?), a space is usually encoded as a +

GET /url?var=foo+bar HTTP/1.1 

rather than

GET /url?var=foo%20bar HTTP/1.1 

Java: notify() vs. notifyAll() all over again

While there are some solid answers above, I am surprised by the number of confusions and misunderstandings I have read. This probably proves the idea that one should use java.util.concurrent as much as possible instead of trying to write their own broken concurrent code.

Back to the question: to summarize, the best practice today is to AVOID notify() in ALL situations due to the lost wakeup problem. Anyone who doesn't understand this should not be allowed to write mission critical concurrency code. If you are worried about the herding problem, one safe way to achieve waking one thread up at a time is to:

  1. Build an explicit waiting queue for the waiting threads;
  2. Have each of the thread in the queue wait for its predecessor;
  3. Have each thread call notifyAll() when done.

Or you can use Java.util.concurrent.*, which have already implemented this.

How to do a logical OR operation for integer comparison in shell scripting?

If a bash script

If [[ $input -gt number  ||  $input  -lt number  ]]
    echo .........
    echo .........



How to delete Tkinter widgets from a window?

I found that when the widget is part of a function and the grid_remove is part of another function it does not remove the label. In this example...

def somefunction(self):
    Label(self, text=" ").grid(row = 0, column = 0)
    self.text_ent = Entry(self)
    self.text_ent.grid(row = 1, column = 0)
def someotherfunction(self):

...there is no valid way of removing the Label.

The only solution I could find is to give the label a name and make it global:

def somefunction(self):
    global label
    label = Label(self, text=" ")
    label.grid(row = 0, column = 0)
    self.text_ent = Entry(self)
    self.text_ent.grid(row = 1, column = 0)
def someotherfunction(self):
    global label

When I ran into this problem there was a class involved, one function being in the class and one not, so I'm not sure the global label lines are really needed in the above.

Correct mime type for .mp4

video/mp4should be used when you have video content in your file. If there is none, but there is audio, you should use audio/mp4. If no audio and no video is used, for instance if the file contains only a subtitle track or a metadata track, the MIME should be application/mp4. Also, as a server, you should try to include the codecs or profiles parameters as defined in RFC6381, as this will help clients determine if they can play the file, prior to downloading it.

Convert varchar into datetime in SQL Server

I'd use STUFF to insert dividing chars and then use CONVERT with the appropriate style. Something like this:

DECLARE @dt VARCHAR(100)='111290';

First you use two times STUFF to get 11/12/90 instead of 111290, than you use the 3 to convert this to datetime (or any other fitting format: use . for german, - for british...) More details on CAST and CONVERT

Best was, to store date and time values properly.

  • This should be either "universal unseparated format" yyyyMMdd
  • or (especially within XML) it should be ISO8601: yyyy-MM-dd or yyyy-MM-ddThh:mm:ss More details on ISO8601

Any culture specific format will lead into troubles sooner or later...

Raise an event whenever a property's value changed?

public event EventHandler ImageFullPath1Changed;

public string ImageFullPath1
        // insert getter logic
        // insert setter logic       

        // EDIT -- this example is not thread safe -- do not use in production code
        if (ImageFullPath1Changed != null && value != _backingField)
            ImageFullPath1Changed(this, new EventArgs(/*whatever*/);

That said, I completely agree with Ryan. This scenario is precisely why INotifyPropertyChanged exists.

What's the best way to check if a file exists in C?

Look up the access() function, found in unistd.h. You can replace your function with

if( access( fname, F_OK ) == 0 ) {
    // file exists
} else {
    // file doesn't exist

You can also use R_OK, W_OK, and X_OK in place of F_OK to check for read permission, write permission, and execute permission (respectively) rather than existence, and you can OR any of them together (i.e. check for both read and write permission using R_OK|W_OK)

Update: Note that on Windows, you can't use W_OK to reliably test for write permission, since the access function does not take DACLs into account. access( fname, W_OK ) may return 0 (success) because the file does not have the read-only attribute set, but you still may not have permission to write to the file.

Don't understand why UnboundLocalError occurs (closure)

To answer the question in your subject line,* yes, there are closures in Python, except they only apply inside a function, and also (in Python 2.x) they are read-only; you can't re-bind the name to a different object (though if the object is mutable, you can modify its contents). In Python 3.x, you can use the nonlocal keyword to modify a closure variable.

def incrementer():
    counter = 0
    def increment():
        nonlocal counter
        counter += 1
        return counter
    return increment

increment = incrementer()

increment()   # 1
increment()   # 2

* The question origially asked about closures in Python.

What would be the best method to code heading/title for <ul> or <ol>, Like we have <caption> in <table>?

Always use heading tags for headings. The clue is in the name :)

If you don’t want them to be bold, change their style with CSS. For example:


<h3 class="list-heading">heading</h3>

    <li>list item </li>
    <li>list item </li>
    <li>list item </li>


.list-heading {
    font-weight: normal;

In HTML5, you can associate the heading and the list more clearly by using the <section> element. (<section> doesn’t work properly in IE 8 and earlier without some JavaScript though.)


        <li>list item </li>
        <li>list item </li>
        <li>list item </li>

You could do something similar in HTML 4:

<div class="list-with-heading">

        <li>list item </li>
        <li>list item </li>
        <li>list item </li>

Then style thus:

.list-with-heading h3 {
    font-weight: normal;

jQuery Upload Progress and AJAX file upload

Here are some options for using AJAX to upload files:

UPDATE: Here is a JQuery plug-in for Multiple File Uploading.

iOS - UIImageView - how to handle UIImage image orientation

extension UIImage {
    func fixImageOrientation() -> UIImage {
        self.draw(at: .zero)
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        return newImage ?? self
  1. Create extension like top example.
  2. Call it: imageView.image?.fixImageOrientation() or UIImage(named: "someImage").fixImageOrientation()

  3. Good luck all!

PHP save image file

No need to create a GD resource, as someone else suggested.

$input = '';
$output = '';
file_put_contents($output, file_get_contents($input));

Note: this solution only works if you're setup to allow fopen access to URLs. If the solution above doesn't work, you'll have to use cURL.

Change mysql user password using command line

Before MySQL 5.7.6 this works from the command line:

mysql -e "SET PASSWORD FOR 'root'@'localhost' = PASSWORD('$w0rdf1sh');"

I don't have a mysql install to test on but I think in your case it would be

mysql -e "UPDATE mysql.user SET Password=PASSWORD('$w0rdf1sh') WHERE User='tate256';"

Swift UIView background color opacity

The question is old, but it seems that there are people who have the same concerns.

What do you think of the opinion that 'the alpha property of UIColor and the opacity property of Interface Builder are applied differently in code'?

The two views created in Interface Builder were initially different colors, but had to be the same color when the conditions changed. So, I had to set the background color of one view in code, and set a different value to make the background color of both views the same.

As an actual example, the background color of Interface Builder was 0x121212 and the Opacity value was 80%(in Amani Elsaed's image :: Red: 18, Green: 18, Blue: 18, Hex Color #: [121212], Opacity: 80), In the code, I set the other view a background color of 0x121212 with an alpha value of 0.8.

self.myFuncView.backgroundColor = UIColor(red: 18, green: 18, blue: 18, alpha: 0.8)

extension is

extension UIColor {
    convenience init(red: Int, green: Int, blue: Int, alpha: CGFloat = 1.0) {
        self.init(red: CGFloat(red) / 255.0,
                  green: CGFloat(green) / 255.0,
                  blue: CGFloat(blue) / 255.0,
                  alpha: alpha)

However, the actual view was

  • 'View with background color specified in Interface Builder': R 0.09 G 0.09 B 0.09 alpha 0.8.
  • 'View with background color by code': R 0.07 G 0.07 B 0.07 alpha 0.8

Calculating it,

  • 0x12 = 18(decimal)
  • 18/255 = 0.07058...
  • 255 * 0.09 = 22.95
  • 23(decimal) = 0x17

So, I was able to match the colors similarly by setting the UIColor values ??to 17, 17, 17 and alpha 0.8.

self.myFuncView.backgroundColor = UIColor(red: 17, green: 17, blue: 17, alpha: 0.8)

Or can anyone tell me what I'm missing?

How to extract this specific substring in SQL Server?

An alternative to the answer provided by @Marc


This makes sure the delimiters exist, and solves an issue with the currently accepted answer where doing the LEFT last is working with the position of the last delimiter in the original string, rather than the revised substring.

Wait until ActiveWorkbook.RefreshAll finishes - VBA

Try executing:


I use it in a worksheet in which control buttons change values of a dataset. On each click, Excel runs through this command and the graph updates immediately.

Why is Thread.Sleep so harmful

For those of you who hasn't seen one valid argument against use of Thread.Sleep in SCENARIO 2, there really is one - application exit be held up by the while loop (SCENARIO 1/3 is just plain stupid so not worthy of more mentioning)

Many who pretend to be in-the-know, screaming Thread.Sleep is evil failed to mentioned a single valid reason for those of us who demanded a practical reason not to use it - but here it is, thanks to Pete - Thread.Sleep is Evil (can be easily avoided with a timer/handler)

    static void Main(string[] args)
        Thread t = new Thread(new ThreadStart(ThreadFunc));

        Console.WriteLine("Hit any key to exit.");

        Console.WriteLine("App exiting");

    static void ThreadFunc()
        int i=0;
            while (true)
                Console.WriteLine(Thread.CurrentThread.ThreadState.ToString() + " " + i);

                Thread.Sleep(1000 * 10);
            Console.WriteLine("Exiting while loop");

Evaluating a mathematical expression in a string

eval is evil

eval("__import__('os').remove('important file')") # arbitrary commands
eval("9**9**9**9**9**9**9**9", {'__builtins__': None}) # CPU, memory

Note: even if you use set __builtins__ to None it still might be possible to break out using introspection:

eval('(1).__class__.__bases__[0].__subclasses__()', {'__builtins__': None})

Evaluate arithmetic expression using ast

import ast
import operator as op

# supported operators
operators = {ast.Add: op.add, ast.Sub: op.sub, ast.Mult: op.mul,
             ast.Div: op.truediv, ast.Pow: op.pow, ast.BitXor: op.xor,
             ast.USub: op.neg}

def eval_expr(expr):
    >>> eval_expr('2^6')
    >>> eval_expr('2**6')
    >>> eval_expr('1 + 2*3**(4^5) / (6 + -7)')
    return eval_(ast.parse(expr, mode='eval').body)

def eval_(node):
    if isinstance(node, ast.Num): # <number>
        return node.n
    elif isinstance(node, ast.BinOp): # <left> <operator> <right>
        return operators[type(node.op)](eval_(node.left), eval_(node.right))
    elif isinstance(node, ast.UnaryOp): # <operator> <operand> e.g., -1
        return operators[type(node.op)](eval_(node.operand))
        raise TypeError(node)

You can easily limit allowed range for each operation or any intermediate result, e.g., to limit input arguments for a**b:

def power(a, b):
    if any(abs(n) > 100 for n in [a, b]):
        raise ValueError((a,b))
    return op.pow(a, b)
operators[ast.Pow] = power

Or to limit magnitude of intermediate results:

import functools

def limit(max_=None):
    """Return decorator that limits allowed returned values."""
    def decorator(func):
        def wrapper(*args, **kwargs):
            ret = func(*args, **kwargs)
                mag = abs(ret)
            except TypeError:
                pass # not applicable
                if mag > max_:
                    raise ValueError(ret)
            return ret
        return wrapper
    return decorator

eval_ = limit(max_=10**100)(eval_)


>>> evil = "__import__('os').remove('important file')"
>>> eval_expr(evil) #doctest:+IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
>>> eval_expr("9**9")
>>> eval_expr("9**9**9**9**9**9**9**9") #doctest:+IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):

How to choose the id generation strategy when using JPA and Hibernate

I find this lecture very valuable, in point 3 it summarizes these generators and also gives some performance analysis and guideline one when you use each one.

Decimal or numeric values in regular expression validation

I had the same problem, but I also wanted ".25" to be a valid decimal number. Here is my solution using JavaScript:

function isNumber(v) {
  // [0-9]* Zero or more digits between 0 and 9  (This allows .25 to be considered valid.)
  // ()? Matches 0 or 1 things in the parentheses.  (Allows for an optional decimal point)
  // Decimal point escaped with \.
  // If a decimal point does exist, it must be followed by 1 or more digits [0-9]
  // \d and [0-9] are equivalent 
  // ^ and $ anchor the endpoints so tthe whole string must match.
  return v.trim().length > 0 && v.trim().match(/^[0-9]*(\.[0-9]+)?$/);

Where my trim() method is

String.prototype.trim = function() {
  return this.replace(/(^\s*|\s*$)/g, "");

Matthew DesVoigne

How to get host name with port from a http or https request

You can use HttpServletRequest.getScheme() to retrieve either "http" or "https".

Using it along with HttpServletRequest.getServerName() should be enough to rebuild the portion of the URL you need.

You don't need to explicitly put the port in the URL if you're using the standard ones (80 for http and 443 for https).

Edit: If your servlet container is behind a reverse proxy or load balancer that terminates the SSL, it's a bit trickier because the requests are forwarded to the servlet container as plain http. You have a few options:

1) Use HttpServletRequest.getHeader("x-forwarded-proto") instead; this only works if your load balancer sets the header correctly (Apache should afaik).

2) Configure a RemoteIpValve in JBoss/Tomcat that will make getScheme() work as expected. Again, this will only work if the load balancer sets the correct headers.

3) If the above don't work, you could configure two different connectors in Tomcat/JBoss, one for http and one for https, as described in this article.

Most Useful Attributes

Being a middle tier developer I like

System.ComponentModel.EditorBrowsableAttribute Allows me to hide properties so that the UI developer is not overwhelmed with properties that they don't need to see.

System.ComponentModel.BindableAttribute Some things don't need to be databound. Again, lessens the work the UI developers need to do.

I also like the DefaultValue that Lawrence Johnston mentioned.

System.ComponentModel.BrowsableAttribute and the Flags are used regularly.

I use System.STAThreadAttribute System.ThreadStaticAttribute when needed.

By the way. I these are just as valuable for all the .Net framework developers.

Cannot install packages inside docker Ubuntu image

You need to update the package list in your Ubuntu:

$ sudo apt-get update
$ sudo apt-get install <package_name>

How to turn a String into a JavaScript function call?

JavaScript has an eval function that evaluates a string and executes it as code:

eval(settings.functionName + '(' + + ')');

How to convert interface{} to string?

To expand on what Peter said: Since you are looking to go from interface{} to string, type assertion will lead to headaches since you need to account for multiple incoming types. You'll have to assert each type possible and verify it is that type before using it.

Using fmt.Sprintf ( automatically handles the interface conversion. Since you know your desired output type is always a string, Sprintf will handle whatever type is behind the interface without a bunch of extra code on your behalf.

What is a smart pointer and when should I use one?

A smart pointer is an object that acts like a pointer, but additionally provides control on construction, destruction, copying, moving and dereferencing.

One can implement one's own smart pointer, but many libraries also provide smart pointer implementations each with different advantages and drawbacks.

For example, Boost provides the following smart pointer implementations:

  • shared_ptr<T> is a pointer to T using a reference count to determine when the object is no longer needed.
  • scoped_ptr<T> is a pointer automatically deleted when it goes out of scope. No assignment is possible.
  • intrusive_ptr<T> is another reference counting pointer. It provides better performance than shared_ptr, but requires the type T to provide its own reference counting mechanism.
  • weak_ptr<T> is a weak pointer, working in conjunction with shared_ptr to avoid circular references.
  • shared_array<T> is like shared_ptr, but for arrays of T.
  • scoped_array<T> is like scoped_ptr, but for arrays of T.

These are just one linear descriptions of each and can be used as per need, for further detail and examples one can look at the documentation of Boost.

Additionally, the C++ standard library provides three smart pointers; std::unique_ptr for unique ownership, std::shared_ptr for shared ownership and std::weak_ptr. std::auto_ptr existed in C++03 but is now deprecated.

SQL Server - find nth occurrence in a string

I decided to use a recursive function because for me it was easier to follow the logic. Note that SQL Server has a default function recursion limit of 32, so this is only good for smaller workloads.

create function dbo._charindex_nth (
  @FindThis varchar(8000),
  @InThis varchar(max),
  @StartFrom int,
  @NthOccurence tinyint
returns bigint
  Recursive helper used by dbo.charindex_nth to return the position of the nth occurance of @FindThis in @InThis

  Who   When    What
  PJR   160421  Initial   

  declare @Pos bigint

  if isnull(@NthOccurence, 0) <= 0 or isnull(@StartFrom, 0) <= 0
    select @Pos = 0
  end else begin
    if @NthOccurence = 1
      select @Pos = charindex(@FindThis, @InThis, @StartFrom)
    end else begin
      select @Pos = dbo._charindex_nth(@FindThis, @InThis, nullif(charindex(@FindThis, @InThis, @StartFrom), 0) + 1, @NthOccurence - 1)

  return @Pos

create function dbo.charindex_nth (
  @FindThis varchar(8000),
  @InThis varchar(max),
  @NthOccurence tinyint
returns bigint
  Returns the position of the nth occurance of @FindThis in @InThis

  Who   When    What
  PJR   160421  Initial   

  return dbo._charindex_nth(@FindThis, @InThis, 1, @NthOccurence)

declare @val varchar(max) = 'zzz_12_3_3_45.gif'

select dbo.charindex_nth('_', @val, 1) Underscore1
  , dbo.charindex_nth('_', @val, 2) Underscore2
  , dbo.charindex_nth('_', @val, 3) Underscore3
  , dbo.charindex_nth('_', @val, 4) Underscore4

Less aggressive compilation with CSS3 calc

A very common usecase of calc is take 100% width and adding some margin around the element.

One can do so with:

@someMarginVariable = 15px;

margin: @someMarginVariable;
width: calc(~"100% - "@someMarginVariable*2);
width: -moz-calc(~"100% - "@someMarginVariable*2);
width: -webkit-calc(~"100% - "@someMarginVariable*2);

Sequence contains no elements?

Well, what is ID here? In particular, is it a local variable? There are some scope / capture issues, which mean that it may be desirable to use a second variable copy, just for the query:

var id = ID;
BlogPost post = (from p in dc.BlogPosts
                 where p.BlogPostID == id
                 select p).Single();

Also; if this is LINQ-to-SQL, then in the current version you get a slightly better behaviour if you use the form:

var id = ID;
BlogPost post = dc.BlogPosts.Single(p => p.BlogPostID == id);

How to retrieve the LoaderException property?

catch (ReflectionTypeLoadException ex)
    foreach (var item in ex.LoaderExceptions)

I'm sorry for resurrecting an old thread, but wanted to post a different solution to pull the loader exception (Using the actual ReflectionTypeLoadException) for anybody else to come across this.

How to declare an array of objects in C#

you need to initialize the object elements of the array.

GameObject[] houses = new GameObject[200];

for (int i=0;`i<house` i<houses.length; i++)
{ houses[i] = new GameObject();}

Of course you initialize elements selectively using different constructors anywhere else before you reference them.

Export DataBase with MySQL Workbench with INSERT statements

If you want to export just single table, or subset of data from some table, you can do it directly from result window:

  1. Click export button: enter image description here

  2. Change Save as type to "SQL Insert statements" enter image description here

How do you get a list of the names of all files present in a directory in Node.js?

I usually use: FS-Extra.

const fileNameArray = Fse.readdir('/some/path');



JQuery Number Formatting

If you need to handle multiple currencies, various number formats etc. I can recommend autoNumeric. Works a treat. Have been using it successfully for several years now.

Convert an integer to an array of digits

First take input from the user as int, convert it into String, and make a character array of size of str.length(). Now populate a character array with a for loop using charAt().

Scanner sc = new Scanner(;
int num = sc.nextInt();
String str = Integer.toString(num);
char [] ch = new char [str.length()];

for(int i=0; i<str.length(); i++)
    ch[i] = str.charAt(i);

for(char c: ch)
    System.out.print(c +" ");

WPF Button with Image

Another way to Stretch image to full button. Can try the below code.

  <ImageBrush x:Key="AddButtonImageBrush" ImageSource="/Demoapp;component/Resources/AddButton.png" Stretch="UniformToFill"/>

<Button Content="Load Inventory 1" Background="{StaticResource AddButtonImageBrush}"/> 

Referred from Here

Also it might helps other. I posted the same with MouseOver Option here.

How to put sshpass command inside a bash script?

I didn't understand how the accepted answer answers the actual question of how to run any commands on the server after sshpass is given from within the bash script file. For that reason, I'm providing an answer.

After your provided script commands, execute additional commands like below:

sshpass -p 'password' ssh user@host "ls; whois;" #or whichever commands you would like to use, for multiple commands provide a semicolon ; after the command

In your script:

#! /bin/bash

sshpass -p 'password' ssh user@host "ls; whois;"

How do I install the yaml package for Python?

Type in pip3 install yaml or like Connor pip3 install strictyaml

How can I find the first occurrence of a sub-string in a python string?

Quick Overview: index and find

Next to the find method there is as well index. find and index both yield the same result: returning the position of the first occurrence, but if nothing is found index will raise a ValueError whereas find returns -1. Speedwise, both have the same benchmark results.

s.find(t)    #returns: -1, or index where t starts in s
s.index(t)   #returns: Same as find, but raises ValueError if t is not in s

Additional knowledge: rfind and rindex:

In general, find and index return the smallest index where the passed-in string starts, and rfind and rindex return the largest index where it starts Most of the string searching algorithms search from left to right, so functions starting with r indicate that the search happens from right to left.

So in case that the likelihood of the element you are searching is close to the end than to the start of the list, rfind or rindex would be faster.

s.rfind(t)   #returns: Same as find, but searched right to left
s.rindex(t)  #returns: Same as index, but searches right to left

Source: Python: Visual QuickStart Guide, Toby Donaldson

How to Implement Custom Table View Section Headers and Footers with Storyboard

Similar to laszlo answer but you can reuse the same prototype cell for both the table cells and the section header cell. Add the first two functions below to your UIViewController subClass

override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
let cell = tableView.dequeueReusableCell(withIdentifier: "DataCell") as! DataCell
    cell.data1Label.text = "DATA KEY"
    cell.data2Label.text = "DATA VALUE"
    return cell

override func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
    return 75

// Example of regular data cell dataDelegate to round out the example
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "DataCell", for: indexPath) as! PlayerCell

    cell.data1Label.text = "\(dataList[indexPath.row].key)"
    cell.data2Label.text = "\(dataList[indexPath.row].value)"
    return cell


Select into for large datasets may be good only for a single user using one single connection to the database doing a bulk operation task. I do not recommend to use


as this creates one big transaction and creates schema lock to create the object, preventing other users to create object or access system objects until the SELECT INTO operation completes.

As proof of concept open 2 sessions, in first session try to use

select into temp table from a huge table 

and in the second section try to

create a temp table 

and check the locks, blocking and the duration of second session to create a temp table object. My recommendation it is always a good practice to create and Insert statement and if needed for minimal logging use trace flag 610.

Find out which remote branch a local branch is tracking

If you want to find the upstream for any branch (as opposed to just the one you are on), here is a slight modification to @cdunn2001's answer:

git rev-parse --abbrev-ref --symbolic-full-name YOUR_LOCAL_BRANCH_NAME@{upstream}

That will give you the remote branch name for the local branch named YOUR_LOCAL_BRANCH_NAME.

Create a Dropdown List for MVC3 using Entity Framework (.edmx Model) & Razor Views && Insert A Database Record to Multiple Tables

Don't pass db models directly to your views. You're lucky enough to be using MVC, so encapsulate using view models.

Create a view model class like this:

public class EmployeeAddViewModel
    public Employee employee { get; set; }
    public Dictionary<int, string> staffTypes { get; set; }
    // really? a 1-to-many for genders
    public Dictionary<int, string> genderTypes { get; set; }

    public EmployeeAddViewModel() { }
    public EmployeeAddViewModel(int id)
        employee = someEntityContext.Employees
            .Where(e => e.ID == id).SingleOrDefault();

        // instantiate your dictionaries

        foreach(var staffType in someEntityContext.StaffTypes)
            staffTypes.Add(staffType.ID, staffType.Type);

        // repeat similar loop for gender types


public ActionResult Add()
    return View(new EmployeeAddViewModel());

public ActionResult Add(EmployeeAddViewModel vm)
        return View("Index"); // or wherever you go after successful add

    return View(vm);

Then, finally in your view (which you can use Visual Studio to scaffold it first), change the inherited type to ShadowVenue.Models.EmployeeAddViewModel. Also, where the drop down lists go, use:

@Html.DropDownListFor(model => model.employee.staffTypeID,
    new SelectList(model.staffTypes, "ID", "Type"))

and similarly for the gender dropdown

@Html.DropDownListFor(model => model.employee.genderID,
    new SelectList(model.genderTypes, "ID", "Gender"))

Update per comments

For gender, you could also do this if you can be without the genderTypes in the above suggested view model (though, on second thought, maybe I'd generate this server side in the view model as IEnumerable). So, in place of new SelectList... below, you would use your IEnumerable.

@Html.DropDownListFor(model => model.employee.genderID,
    new SelectList(new SelectList()
        new { ID = 1, Gender = "Male" },
        new { ID = 2, Gender = "Female" }
    }, "ID", "Gender"))

Finally, another option is a Lookup table. Basically, you keep key-value pairs associated with a Lookup type. One example of a type may be gender, while another may be State, etc. I like to structure mine like this:

ID | LookupType | LookupKey | LookupValue | LookupDescription | Active
1  | Gender     | 1         | Male        | male gender       | 1
2  | State      | 50        | Hawaii      | 50th state        | 1
3  | Gender     | 2         | Female      | female gender     | 1
4  | State      | 49        | Alaska      | 49th state        | 1
5  | OrderType  | 1         | Web         | online order      | 1

I like to use these tables when a set of data doesn't change very often, but still needs to be enumerated from time to time.

Hope this helps!

Using reCAPTCHA on localhost

i got error related to recaptcha in laravel website, i resolved it by using some command and with env file and above answer will also help in this problem.

first of all check env file(in your case file which has google recaptcha key) for google recpatcha key.

second run these command :

  1. php artisan config:clear
  2. php artisan cache:clear
  3. composer dump-autoload
  4. php artisan view:clear
  5. php artisan route:clear

    it will solve your problem

Runtime error: Could not load file or assembly 'System.Web.WebPages.Razor, Version=

I got this error because such DLL (and many others) were missing in bin folder when I pubished the web application. It seemed like a bug in Visual Studio publish function. Cleaning, recompiling and publishing it again, made such DLLs to be published correctly.

How can I include css files using node, express, and ejs?

The above responses half worked and I'm not why they didn't on my machine but I had to do the following for it work.

  1. Created a directory at the root


  2. Paste this into your server.js file with name matching the name of directory created above. Note adding /public as the first param


  3. Finally in the HTML page to which to import the javascript file into,

    <script src="public/js/bundle.js"></script>

How do I upload a file with metadata using a REST web service?

If your file and its metadata creating one resource, its perfectly fine to upload them both in one request. Sample request would be :


Accept: application/json

Content-Type: multipart/form-data; 




Content-Disposition: form-data; name="application/json"

{"markers": [
            "point":new GLatLng(40.266044,-74.718479), 
            "homeTeam":"Lawrence Library",
            "information": "Linux users group meets second Wednesday of each month.",
            "fixture":"Wednesday 7pm",
            "point":new GLatLng(40.211600,-74.695702),
            "homeTeam":"Hamilton Library",
            "awayTeam":"LUGip HW SIG",
            "information": "Linux users can meet the first Tuesday of the month to work out harward and configuration issues.",
            "fixture":"Tuesday 7pm",
            "point":new GLatLng(40.294535,-74.682012),
            "awayTeam":"After LUPip Mtg Spot",
            "information": "Some of us go there after the main LUGip meeting, drink brews, and talk.",
            "fixture":"Wednesday whenever",
            "capacity":"2 to 4 pints",
] }


Content-Disposition: form-data; name="name"; filename="myfilename.pdf"

Content-Type: application/octet-stream

2 0 obj
<</Length 57/Filter/FlateDecode>>stream
)%[email protected]
4 0 obj
<</Type/Page/MediaBox[0 0 595 842]/Resources<</Font<</F1 1 0 R>>>>/Contents 2 0 R/Parent 3 0 R>>
1 0 obj
3 0 obj
<</Type/Pages/Count 1/Kids[4 0 R]>>
5 0 obj
<</Type/Catalog/Pages 3 0 R>>
6 0 obj
<</Producer(iTextSharp 5.5.11 2000-2017 iText Group NV \(AGPL-version\))/CreationDate(D:20170630120636+02'00')/ModDate(D:20170630120636+02'00')>>
0 7
0000000000 65535 f 
0000000250 00000 n 
0000000015 00000 n 
0000000338 00000 n 
0000000138 00000 n 
0000000389 00000 n 
0000000434 00000 n 
<</Size 7/Root 5 0 R/Info 6 0 R/ID [<c7c34272c2e618698de73f4e1a65a1b5><c7c34272c2e618698de73f4e1a65a1b5>]>>


Get the directory from a file path in java (android)

You could also use FilenameUtils from Apache. It provides you at least the following features for the example C:\dev\project\file.txt:

  • the prefix - C:\
  • the path - dev\project\
  • the full path - C:\dev\project\
  • the name - file.txt
  • the base name - file
  • the extension - txt

How to get the size of a range in Excel

The Range object has both width and height properties, which are measured in points.

Resize height with Highcharts

You must set the height of the container explicitly

#container {

See other Stackoverflow answer

Highcharts documentation

Should I use Vagrant or Docker for creating an isolated environment?

Vagrant-lxc is a plugin for Vagrant that let's you use LXC to provision Vagrant. It does not have all the features that the default vagrant VM (VirtualBox) has but it should allow you more flexibility than docker containers. There is a video in the link showing its capabilities that is worth watching.

Microsoft Visual C++ Compiler for Python 3.4

Unfortunately to be able to use the extension modules provided by others you'll be forced to use the official compiler to compile Python. These are:

Alternatively, you can use MinGw to compile extensions in a way that won't depend on others.

See: or

This allows you to have one compiler to build your extensions for both versions of Python, Python 2.x and Python 3.x.

Unit Testing C Code

I don't use a framework, I just use autotools "check" target support. Implement a "main" and use assert(s).

My test dir look like:

check_PROGRAMS = test_oe_amqp

test_oe_amqp_SOURCES = test_oe_amqp.c
test_oe_amqp_LDADD = -L$(top_builddir)/components/common -loecommon
test_oe_amqp_CFLAGS = -I$(top_srcdir)/components/common -static

TESTS = test_oe_amqp

Bootstrap push div content to new line

If your your list is dynamically generated with unknown number and your target is to always have last div in a new line set last div class to "col-xl-12" and remove other classes so it will always take a full row.

This is a copy of your code corrected so that last div always occupy a full row (I although removed unnecessary classes).

<link href="" rel="stylesheet">_x000D_
<div class="grid">_x000D_
  <div class="row">_x000D_
    <div class="col-sm-3">Under me should be a DIV</div>_x000D_
    <div class="col-md-6 col-sm-5">Under me should be a DIV</div>_x000D_
    <div class="col-xl-12">I am the last DIV and I always take a full row for my self!!</div>_x000D_

Suppress warning messages using mysql from within Terminal, but password written in bash script

It worked for me- Just added 2> null after the $(mysql_command), and it will suppress the Errors and Warning messages only.

Using G++ to compile multiple .cpp and .h files

You can use several g++ commands and then link, but the easiest is to use a traditional Makefile or some other build system: like Scons (which are often easier to set up than Makefiles).

Trying to include a library, but keep getting 'undefined reference to' messages

If the .c source files are converted .cpp (like as in parsec), then the extern needs to be followed by "C" as in

extern "C" void foo();

Make HTML5 video poster be same size as video itself

You can use poster to show image instead of video on mobile device(or devices which doesn't support the video autoplay functionality). Because mobile devices not support video autoplay functionality.

<div id="wrap_video">
<video preload="preload" id="Video" autoplay="autoplay" loop="loop" poster="default.jpg">
<source src="Videos.mp4" type="video/mp4">
Your browser does not support the <code>video</code> tag.

Now you can just style the poster attribute which is inside the video tag for mobile device via media-query.

position: relative;
@media (min-width:360px) and (max-width:780px)
top:0 !important;
left:0 !important;
width:480px !important;
height:360px !important;
position: absolute !important;

Emulator error: This AVD's configuration is missing a kernel file

Here's my story. Under 'Actions' on the AVD manager, I viewed the details for the AVD which wasn't working. Scrolling down, I found the line:

image.sysdir.1: add-ons\addon-google_apis-google-16\images\armeabi-v7a\

I then navigated to this file at:


I found there was no kernel file. However, I did find a kernel file at:


So I copied it and pasted back into:


The AVD then worked.

How to pass parameters to $http in angularjs?

We can use input data to pass it as a parameter in the HTML file w use ng-model to bind the value of input field.

<input type="text" placeholder="Enter your Email" ng-model="email" required>

<input type="text" placeholder="Enter your password " ng-model="password" required> 

and in the js file w use $scope to access this data:


Controller function will be something like that:

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

    app.controller('assignController', function($scope, $http) {

        method: "POST",
        url: "http://localhost:3000/users/sign_in",
        params: {email: $, password: $scope.password}

      }).then(function mySuccess(response) {
          // a string, or an object, carrying the response from the server.
          $scope.myRes =;
          $scope.statuscode = response.status;

        }, function myError(response) {
          $scope.myRes = response.statusText;

Setting the Textbox read only property to true using JavaScript

Using, I believe you can do it this way :


Calculating text width

after chasing a ghost for two days, trying to figure out why the width of a text was incorrect, i realized it was because of white spaces in the text string that would stop the width calculation.

so, another tip is to check if the whitespaces are causing problems. use


non-breaking space and see if that fixes it up.

the other functions people suggested work well too, but it was the whitespaces causing trouble.

Postgres "psql not recognized as an internal or external command"

Even if it is a little bit late, i solved the PATH problem by removing every space.

;C:\Program Files\PostgreSQL\9.5\bin;C:\Program Files\PostgreSQL\9.5\lib

works for me now.

Get Last Part of URL PHP

If you are looking for a robust version that can deal with any form of URLs, this should do nicely:


$url = "";
$lastSegment = basename(parse_url($url, PHP_URL_PATH));

JPA : How to convert a native query result set to POJO class collection

First declare following annotations:

public @interface NativeQueryResultEntity {

public @interface NativeQueryResultColumn {
    int index();

Then annotate your POJO as follows:

public class ClassX {
    private String a;

    private String b;

Then write annotation processor:

public class NativeQueryResultsMapper {

    private static Logger log = LoggerFactory.getLogger(NativeQueryResultsMapper.class);

    public static <T> List<T> map(List<Object[]> objectArrayList, Class<T> genericType) {
        List<T> ret = new ArrayList<T>();
        List<Field> mappingFields = getNativeQueryResultColumnAnnotatedFields(genericType);
        try {
            for (Object[] objectArr : objectArrayList) {
                T t = genericType.newInstance();
                for (int i = 0; i < objectArr.length; i++) {
                    BeanUtils.setProperty(t, mappingFields.get(i).getName(), objectArr[i]);
        } catch (InstantiationException ie) {
            log.debug("Cannot instantiate: ", ie);
        } catch (IllegalAccessException iae) {
            log.debug("Illegal access: ", iae);
        } catch (InvocationTargetException ite) {
            log.debug("Cannot invoke method: ", ite);
        return ret;

    // Get ordered list of fields
    private static <T> List<Field> getNativeQueryResultColumnAnnotatedFields(Class<T> genericType) {
        Field[] fields = genericType.getDeclaredFields();
        List<Field> orderedFields = Arrays.asList(new Field[fields.length]);
        for (int i = 0; i < fields.length; i++) {
            if (fields[i].isAnnotationPresent(NativeQueryResultColumn.class)) {
                NativeQueryResultColumn nqrc = fields[i].getAnnotation(NativeQueryResultColumn.class);
                orderedFields.set(nqrc.index(), fields[i]);
        return orderedFields;

Use above framework as follows:

String sql = "select a,b from x order by a";
Query q = entityManager.createNativeQuery(sql);

List<ClassX> results =, ClassX.class);

How to change value of a request parameter in laravel

Try to:

$requestData = $request->all();
$requestData['img'] = $img;

Another way to do it:

$request->merge(['img' => $img]);

Thanks to @JoelHinz for this.

If you want to add or overwrite nested data:

$data['some']['thing'] = 'value';

If you do not inject Request $request object, you can use the global request() helper or \Request:: facade instead of $request

Windows Forms ProgressBar: Easiest way to start/stop marquee?

It's not how they work. You "start" a marquee style progress bar by making it visible, you stop it by hiding it. You could change the Style property.

Hadoop: «ERROR : JAVA_HOME is not set»

Type echo $JAVA_HOME in your terminal to be sure your JAVA_HOME is set.

You can also type java -version to know what version of java you are actually using.

By the way, reading your description it seems your actually writing

export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk

in the file conf/, you should write it in your terminal or in ~/.bashrc or ~/.profile then type source < path to modified file >.

MySQL load NULL values from CSV data

show variables

Show variables like "`secure_file_priv`";

Note: keep your csv file in location given by the above command.

create table assessments (course_code varchar(5),batch_code varchar(7),id_assessment int, assessment_type varchar(10), date int , weight int);

Note: here the 'date' column has some blank values in the csv file.

LOAD DATA INFILE 'C:/ProgramData/MySQL/MySQL Server 8.0/Uploads/assessments.csv' 
INTO TABLE assessments
SET date = IF(@date = '', NULL, @date);

Checkout another branch when there are uncommitted changes on the current branch

The correct answer is

git checkout -m origin/master

It merges changes from the origin master branch with your local even uncommitted changes.

What is the difference between public, private, and protected?

It is typically considered good practice to default to the lowest visibility required as this promotes data encapsulation and good interface design. When considering member variable and method visibility think about the role the member plays in the interaction with other objects.

If you "code to an interface rather than implementation" then it's usually pretty straightforward to make visibility decisions. In general, variables should be private or protected unless you have a good reason to expose them. Use public accessors (getters/setters) instead to limit and regulate access to a class's internals.

To use a car as an analogy, things like speed, gear, and direction would be private instance variables. You don't want the driver to directly manipulate things like air/fuel ratio. Instead, you expose a limited number of actions as public methods. The interface to a car might include methods such as accelerate(), deccelerate()/brake(), setGear(), turnLeft(), turnRight(), etc.

The driver doesn't know nor should he care how these actions are implemented by the car's internals, and exposing that functionality could be dangerous to the driver and others on the road. Hence the good practice of designing a public interface and encapsulating the data behind that interface.

This approach also allows you to alter and improve the implementation of the public methods in your class without breaking the interface's contract with client code. For example, you could improve the accelerate() method to be more fuel efficient, yet the usage of that method would remain the same; client code would require no changes but still reap the benefits of your efficiency improvement.

Edit: Since it seems you are still in the midst of learning object oriented concepts (which are much more difficult to master than any language's syntax), I highly recommend picking up a copy of PHP Objects, Patterns, and Practice by Matt Zandstra. This is the book that first taught me how to use OOP effectively, rather than just teaching me the syntax. I had learned the syntax years beforehand, but that was useless without understanding the "why" of OOP.

What are the differences between char literals '\n' and '\r' in Java?

On the command line, \r will move the cursor back to the beginning of the current line. To see the difference you must run your code from a command prompt. Eclipse's console show similar output for both the expression. For complete list of escape sequences, click here

Wavy shape with css

I like ThomasA's answer, but wanted a more realistic context with the wave being used to separate two divs. So I created a more complete demo where the separator SVG gets positioned perfectly between the two divs.

css wavy divider in CSS

Now I thought it would be cool to take it further. What if we could do this all in CSS without the need for the inline SVG? The point being to avoid extra markup. Here's how I did it:

Two simple <div>:

/** CSS using pseudo-elements: **/_x000D_
#A {_x000D_
  background: #0074D9;_x000D_
#B {_x000D_
  background: #7FDBFF;_x000D_
#A::after {_x000D_
  content: "";_x000D_
  position: relative;_x000D_
  left: -3rem;_x000D_
  /* padding * -1 */_x000D_
  top: calc( 3rem - 4rem / 2);_x000D_
  /* padding - height/2 */_x000D_
  float: left;_x000D_
  display: block;_x000D_
  height: 4rem;_x000D_
  width: 100vw;_x000D_
  background: hsla(0, 0%, 100%, 0.5);_x000D_
  background-image: url("data:image/svg+xml,%3Csvg xmlns='' viewBox='0 70 500 60' preserveAspectRatio='none'%3E%3Crect x='0' y='0' width='500' height='500' style='stroke: none; fill: %237FDBFF;' /%3E%3Cpath d='M0,100 C150,200 350,0 500,100 L500,00 L0,0 Z' style='stroke: none; fill: %230074D9;'%3E%3C/path%3E%3C/svg%3E");_x000D_
  background-size: 100% 100%;_x000D_
/** Cosmetics **/_x000D_
* {_x000D_
  margin: 0;_x000D_
#B {_x000D_
  padding: 3rem;_x000D_
div {_x000D_
  font-family: monospace;_x000D_
  font-size: 1.2rem;_x000D_
  line-height: 1.2;_x000D_
#A {_x000D_
  color: white;_x000D_
<div id="A">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus nec quam tincidunt, iaculis mi non, hendrerit felis. Nulla pretium lectus et arcu tempus, quis luctus ex imperdiet. In facilisis nulla suscipit ornare finibus. …_x000D_
<div id="B" class="wavy">… In iaculis fermentum lacus vel porttitor. Vestibulum congue elementum neque eget feugiat. Donec suscipit diam ligula, aliquam consequat tellus sagittis porttitor. Sed sodales leo nisl, ut consequat est ornare eleifend. Cras et semper mi, in porta nunc.</div>

Demo Wavy divider (with CSS pseudo-elements to avoid extra markup)

It was a bit trickier to position than with an inline SVG but works just as well. (Could use CSS custom properties or pre-processor variables to keep the height and padding easy to read.)

To edit the colors, you need to edit the URL-encoded SVG itself.

Pay attention (like in the first demo) to a change in the viewBox to get rid of unwanted spaces in the SVG. (Another option would be to draw a different SVG.)

Another thing to pay attention to here is the background-size set to 100% 100% to get it to stretch in both directions.

Change MySQL root password in phpMyAdmin

Explain what video describe to resolve problem

After Changing Password of root (Mysql Account). Accessing to phpmyadmin page will be denied because phpMyAdmin use root/''(blank) as default username/password. To resolve this problem, you need to reconfig phpmyadmin. Edit file in folder %wamp%\apps\phpmyadmin4.1.14 (Not in %wamp%)

$cfg['Servers'][$i]['verbose'] = 'mysql wampserver';
$cfg['Servers'][$i]['auth_type'] = 'config';
$cfg['Servers'][$i]['user'] = 'root';
$cfg['Servers'][$i]['password'] = 'changed';
$cfg['Servers'][$i]['host'] = '';
$cfg['Servers'][$i]['connect_type'] = 'tcp';
$cfg['Servers'][$i]['compress'] = false;
$cfg['Servers'][$i]['extension'] = 'mysqli';
$cfg['Servers'][$i]['AllowNoPassword'] = false;

If you have more than 1 DB server, add "i++" to file and continue add new config as above

Array versus linked-list

Eric Lippert recently had a post on one of the reasons arrays should be used conservatively.

How to delete row based on cell value

if you want to delete rows based on some specific cell value. let suppose we have a file containing 10000 rows, and a fields having value of NULL. and based on that null value want to delete all those rows and records.

here are some simple tip. First open up Find Replace dialog, and on Replace tab, make all those cell containing NULL values with Blank. then press F5 and select the Blank option, now right click on the active sheet, and select delete, then option for Entire row.

it will delete all those rows based on cell value of containing word NULL.

Java finished with non-zero exit value 2 - Android Gradle

Updating my Java SDK to the latest version 1.7.0_79 and updating the SDK Location under Project Structure solved the problem for me.

sql query to get earliest date

SELECT TOP 1 ID, Name, Score, [Date]
FROM myTable
Order BY [Date]

Connection timeout for SQL server

Yes, you could append ;Connection Timeout=30 to your connection string and specify the value you wish.

The timeout value set in the Connection Timeout property is a time expressed in seconds. If this property isn't set, the timeout value for the connection is the default value (15 seconds).

Moreover, setting the timeout value to 0, you are specifying that your attempt to connect waits an infinite time. As described in the documentation, this is something that you shouldn't set in your connection string:

A value of 0 indicates no limit, and should be avoided in a ConnectionString because an attempt to connect waits indefinitely.

Is it possible to insert multiple rows at a time in an SQLite database?

VALUES      (VAL1, 

Modify XML existing content in C#

Forming a XML file

XmlTextWriter xmlw = new XmlTextWriter(@"C:\WINDOWS\Temp\exm.xml",System.Text.Encoding.UTF8);

To edit the Xml nodes use the below code

XmlDocument doc = new XmlDocument(); 
XmlNode root = doc.DocumentElement["Starttime"]; 
root.FirstChild.InnerText = "First"; 
XmlNode root1 = doc.DocumentElement["Changetime"]; 
root1.FirstChild.InnerText = "Second"; 

Try this. It's C# code.

How to create a date object from string in javascript

You definitely want to use the second expression since months in JS are enumerated from 0.

Also you may use Date.parse method, but it uses different date format:

var timestamp = Date.parse("11/30/2011");
var dateObject = new Date(timestamp);

Check mySQL version on Mac 10.8.5

To check your MySQL version on your mac, navigate to the directory where you installed it (default is usr/local/mysql/bin) and issue this command:

./mysql --version

Alternatively, to avoid needing to navigate to that specific dir to run the command, add its location to your path ($PATH). There's more than one way to add a dir to your $PATH (with explanations on stackoverflow and other places on how to do so), such as adding it to your ./bash_profile.

After adding the mysql bin dir to your $PATH, verify it's there by executing:

echo $PATH

Thereafter you can check your mysql version from anywhere by running (note no "./"):

mysql --version

How do I set a program to launch at startup

In addition to Xepher Dotcom's answer, folder path to Windows Startup should be coded that way:

var Startup = Environment.GetFolderPath(Environment.SpecialFolder.Startup);

How to show x and y axes in a MATLAB graph?

The poor man's solution is to simply graph the lines x=0 and y=0. You can adjust the thickness and color of the lines to differentiate them from the graph.

Firebase: how to generate a unique numeric ID for key?

Adding to the @htafoya answer. The code snippet will be

const getTimeEpoch = () => {
    return new Date().getTime().toString();                             

How to script FTP upload and download?

It's a reasonable idea to want to script an FTP session the way the original poster imagined, and that is the kind of thing Expect would help with. Batch files on Windows cannot do this.

But rather than doing cURL or Expect, you may find it easier to script the FTP interaction with Powershell. It's a different model, in that you are not directly scripting the text to send to the FTP server. Instead you will use Powershell to manipulate objects that generate the FTP dialogue for you.


$File = "D:\Dev\"
$ftp = "ftp://username:[email protected]/pub/incoming/"

"ftp url: $ftp"

$webclient = New-Object System.Net.WebClient
$uri = New-Object System.Uri($ftp)

"Uploading $File..."

$webclient.UploadFile($uri, $File)


$File = "c:\store\"
$ftp = "ftp://username:[email protected]/pub/outbound/"

"ftp url: $ftp"

$webclient = New-Object System.Net.WebClient
$uri = New-Object System.Uri($ftp)

"Downloading $File..."

$webclient.DownloadFile($uri, $File)

You need Powershell to do this. If you are not aware, Powershell is a shell like cmd.exe which runs your .bat files. But Powershell runs .ps1 files, and is quite a bit more powerful. Powershell is a free add-on to Windows and will be built-in to future versions of Windows. Get it here.


What is the preferred syntax for defining enums in JavaScript?

In ES7 , you can do an elegant ENUM relying on static attributes:

class ColorEnum  {
    static RED = 0 ;
    static GREEN = 1;
    static BLUE = 2;


if (currentColor === ColorEnum.GREEN ) {/*-- coding --*/}

The advantage ( of using class instead of literal object) is to have a parent class Enum then all your Enums will extends that class.

 class ColorEnum  extends Enum {/*....*/}

How to find the logs on android studio?

My Android Studio is 3.0, please follow the two steps below,hope this will help;) First step. Second step

Java: Replace all ' in a string with \'

Use replace()

 s = s.replace("'", "\\'"); 


You\'ll be totally awesome, I\'m really terrible

Which MySQL datatype to use for an IP address?

For IPv4 addresses, you can use VARCHAR to store them as strings, but also look into storing them as long integesrs INT(11) UNSIGNED. You can use MySQL's INET_ATON() function to convert them to integer representation. The benefit of this is it allows you to do easy comparisons on them, like BETWEEN queries

INET_ATON() MySQL function

How to config routeProvider and locationProvider in angularJS?

Try this

If you are deploying your app into the root context (e.g., set the base URL to /:

  <base href="/">

Angular Documentation

creating a table in ionic

This is the way i use it. It's very simple and work very well.. Ionic html:


  <ion-grid class="ion-text-center">

    <ion-row class="ion-margin">
          <ion-text color="default">
            Your title remove if don't want use

    <ion-row class="header-row">




            R$ 200



.header-row {
  background: #7163AA;
  color: #fff;
  font-size: 18px;

ion-col {
  border: 1px solid #ECEEEF;

Result of the code

How do you easily horizontally center a <div> using CSS?

.center {_x000D_
  height: 20px;_x000D_
  background-color: blue;_x000D_
.center>div {_x000D_
  margin: auto;_x000D_
  background-color: green;_x000D_
  width: 200px;_x000D_
<div class="center">_x000D_
  <div>You text</div>_x000D_


How to resolve compiler warning 'implicit declaration of function memset'

Try to add next define at start of your .c file:

#define _GNU_SOURCE

It helped me with pipe2 function.

How do I return to an older version of our code in Subversion?

There are a lot of dangerous answers on this page. Note that since SVN version 1.6, doing an update -r can cause tree conflicts, which rapidly escalates into a potentially data losing kafkeresque nightmare where you're googling for information on tree conflicts.

The correct way to revert to a version is:

svn merge -r HEAD:12345 .

Where 12345 is the version number. Don't forget the dot.

mongodb, replicates and error: { "$err" : "not master and slaveOk=false", "code" : 13435 }

I got here searching for the same error, but from Node.js native driver. The answer for me was combination of answers by campeterson and Prabhat.

The issue is that readPreference setting defaults to primary, which then somehow leads to the confusing slaveOk error. My problem is that I just wan to read from my replica set from any node. I don't even connect to it as to replicaset. I just connect to any node to read from it.

Setting readPreference to primaryPreferred (or better to the ReadPreference.PRIMARY_PREFERRED constant) solved it for me. Just pass it as an option to MongoClient.connect() or to client.db() or to any find(), aggregate() or other function.

const { MongoClient, ReadPreference } = require('mongodb');
const client = await MongoClient.connect(MONGODB_CONNECTIONSTRING, { readPreference: ReadPreference.PRIMARY_PREFERRED });

How to get instance variables in Python?

You normally can't get instance attributes given just a class, at least not without instantiating the class. You can get instance attributes given an instance, though, or class attributes given a class. See the 'inspect' module. You can't get a list of instance attributes because instances really can have anything as attribute, and -- as in your example -- the normal way to create them is to just assign to them in the __init__ method.

An exception is if your class uses slots, which is a fixed list of attributes that the class allows instances to have. Slots are explained in, but there are various pitfalls with slots; they affect memory layout, so multiple inheritance may be problematic, and inheritance in general has to take slots into account, too.

JavaFX How to set scene background image

You can change style directly for scene using .root class:

.root {
    -fx-background-image: url("");

Add this to CSS and load it as "Uluk Biy" described in his answer.

What's the best way to detect a 'touch screen' device using JavaScript?

I also struggled a lot with different options on how to detect in Javascript whether the page is displayed on a touch screen device or not. IMO, as of now, no real option exists to detect the option properly. Browsers either report touch events on desktop machines (because the OS maybe touch-ready), or some solutions don't work on all mobile devices.

In the end, I realized that I was following the wrong approach from the start: If my page was to look similar on touch and non-touch devices, I maybe shouldn't have to worry about detecting the property at all: My scenario was to deactivate tooltips over buttons on touch devices as they lead to double-taps where I wanted a single tap to activate the button.

My solution was to refactor the view so that no tooltip was needed over a button, and in the end I didn't need to detect the touch device from Javascript with methods that all have their drawbacks.

How to change the color of an svg element?

For Example, in your HTML:

  <svg viewBox="" width="" height="">
    <path id="struct1" fill="#xxxxxx" d="M203.3,71.6c-.........."></path>

Use jQuery:

$("#struct1").css("fill","<desired colour>");

Python 3.6 install win32api?

Take a look at this answer: ImportError: no module named win32api

You can use

pip install pypiwin32

creating triggers for After Insert, After Update and After Delete in SQL

(Update: overlooked a fault in the matter, I have corrected)

(Update2: I wrote from memory the code screwed up, repaired it)

(Update3: check on SQLFiddle)

create table Derived_Values
    BusinessUnit nvarchar(100) not null
    ,Questions nvarchar(100) not null
    ,Answer nvarchar(100)


ALTER TABLE Derived_Values ADD CONSTRAINT PK_Derived_Values
PRIMARY KEY CLUSTERED (BusinessUnit, Questions);

create table Derived_Values_Test
    BusinessUnit nvarchar(150)
    ,Questions nvarchar(100)
    ,Answer nvarchar(100)


CREATE TRIGGER trgAfterUpdate ON  [Derived_Values]
    declare @BusinessUnit nvarchar(50)
    set @BusinessUnit = 'Updated Record -- After Update Trigger.'

    insert into 
        --(BusinessUnit,Questions, Answer) 
        @BusinessUnit + i.BusinessUnit, i.Questions, i.Answer
        inserted i
        inner join deleted d on i.BusinessUnit = d.BusinessUnit


CREATE TRIGGER trgAfterDelete ON  [Derived_Values]
    declare @BusinessUnit nvarchar(50)
    set @BusinessUnit = 'Deleted Record -- After Delete Trigger.'

    insert into 
        --(BusinessUnit,Questions, Answer) 
        @BusinessUnit + d.BusinessUnit, d.Questions, d.Answer
        deleted d


insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU1', 'Q11', 'A11')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU1', 'Q12', 'A12')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU2', 'Q21', 'A21')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU2', 'Q22', 'A22')

UPDATE Derived_Values SET Answer='Updated Answers A11' from Derived_Values WHERE (BusinessUnit = 'BU1') AND (Questions = 'Q11');
UPDATE Derived_Values SET Answer='Updated Answers A12' from Derived_Values WHERE (BusinessUnit = 'BU1') AND (Questions = 'Q12');
UPDATE Derived_Values SET Answer='Updated Answers A21' from Derived_Values WHERE (BusinessUnit = 'BU2') AND (Questions = 'Q21');
UPDATE Derived_Values SET Answer='Updated Answers A22' from Derived_Values WHERE (BusinessUnit = 'BU2') AND (Questions = 'Q22');

delete Derived_Values;

and then:

SELECT * FROM Derived_Values;

select * from Derived_Values_Test;

Record Count: 0;

Updated Record -- After Update Trigger.BU1  Q11 Updated Answers A11
Deleted Record -- After Delete Trigger.BU1  Q11 A11
Updated Record -- After Update Trigger.BU1  Q12 Updated Answers A12
Deleted Record -- After Delete Trigger.BU1  Q12 A12
Updated Record -- After Update Trigger.BU2  Q21 Updated Answers A21
Deleted Record -- After Delete Trigger.BU2  Q21 A21
Updated Record -- After Update Trigger.BU2  Q22 Updated Answers A22
Deleted Record -- After Delete Trigger.BU2  Q22 A22

(Update4: If you want to sync: SQLFiddle)

create table Derived_Values
    BusinessUnit nvarchar(100) not null
    ,Questions nvarchar(100) not null
    ,Answer nvarchar(100)


ALTER TABLE Derived_Values ADD CONSTRAINT PK_Derived_Values
PRIMARY KEY CLUSTERED (BusinessUnit, Questions);

create table Derived_Values_Test
    BusinessUnit nvarchar(150) not null
    ,Questions nvarchar(100) not null
    ,Answer nvarchar(100)


ALTER TABLE Derived_Values_Test ADD CONSTRAINT PK_Derived_Values_Test
PRIMARY KEY CLUSTERED (BusinessUnit, Questions);

CREATE TRIGGER trgAfterInsert ON  [Derived_Values]
        i.BusinessUnit, i.Questions, i.Answer
        inserted i


CREATE TRIGGER trgAfterUpdate ON  [Derived_Values]
    declare @BusinessUnit nvarchar(50)
    set @BusinessUnit = 'Updated Record -- After Update Trigger.'

        --BusinessUnit = i.BusinessUnit
        --,Questions = i.Questions
        Answer = i.Answer
        inner join inserted i 
        [Derived_Values].BusinessUnit = i.BusinessUnit
        [Derived_Values].Questions = i.Questions


CREATE TRIGGER trgAfterDelete ON  [Derived_Values]
        inner join deleted d 
        [Derived_Values_Test].BusinessUnit = d.BusinessUnit
        [Derived_Values_Test].Questions = d.Questions


insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU1', 'Q11', 'A11')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU1', 'Q12', 'A12')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU2', 'Q21', 'A21')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU2', 'Q22', 'A22')

UPDATE Derived_Values SET Answer='Updated Answers A11' from Derived_Values WHERE (BusinessUnit = 'BU1') AND (Questions = 'Q11');
UPDATE Derived_Values SET Answer='Updated Answers A12' from Derived_Values WHERE (BusinessUnit = 'BU1') AND (Questions = 'Q12');
UPDATE Derived_Values SET Answer='Updated Answers A21' from Derived_Values WHERE (BusinessUnit = 'BU2') AND (Questions = 'Q21');
UPDATE Derived_Values SET Answer='Updated Answers A22' from Derived_Values WHERE (BusinessUnit = 'BU2') AND (Questions = 'Q22');

--delete Derived_Values;

And then:

SELECT * FROM Derived_Values;

select * from Derived_Values_Test;

BU1 Q11 Updated Answers A11
BU1 Q12 Updated Answers A12
BU2 Q21 Updated Answers A21
BU2 Q22 Updated Answers A22

BU1 Q11 Updated Answers A11
BU1 Q12 Updated Answers A12
BU2 Q21 Updated Answers A21
BU2 Q22 Updated Answers A22

Excel VBA, error 438 "object doesn't support this property or method

The Error is here

lastrow = wsPOR.Range("A" & Rows.Count).End(xlUp).Row + 1

wsPOR is a workbook and not a worksheet. If you are working with "Sheet1" of that workbook then try this

lastrow = wsPOR.Sheets("Sheet1").Range("A" & _
          wsPOR.Sheets("Sheet1").Rows.Count).End(xlUp).Row + 1


wsPOR.Range("A2:G" & lastrow).Select

should be

wsPOR.Sheets("Sheet1").Range("A2:G" & lastrow).Select

Linq select objects in list where exists IN (A,B,C)

Try with Contains function;

Determines whether a sequence contains a specified element.

var allowedStatus = new[]{ "A", "B", "C" };
var filteredOrders = orders.Order.Where(o => allowedStatus.Contains(o.StatusCode));

How to add content to html body using JS?

I Just came across to a similar to this question solution with included some performance statistics.

It seems that example below is faster:

document.getElementById('container').insertAdjacentHTML('beforeend', '<div id="idChild"> content html </div>');

InnerHTML vs jQuery 1 vs appendChild vs innerAdjecentHTML.

enter image description here

Reference: 1) Performance stats 2) API - insertAdjacentHTML

I hope this will help.

Importing two classes with same name. How to handle?

When you call classes with the same names, you must explicitly specify the package from which the class is called.

You can to do like this:

import first.Foo;

public class Main {
    public static void main(String[] args) {
        System.out.println(new Foo());
        System.out.println(new second.Foo());

package first;

public class Foo {
    public Foo() {

    public String toString() {
        return "Foo{first class}";

package second;

public class Foo {
    public Foo() {

    public String toString() {
        return "Foo{second class}";


Foo{first class}
Foo{second class}

How to insert newline in string literal?

newer .net versions allow you to use $ in front of the literal which allows you to use variables inside like follows:

var x = $"Line 1{Environment.NewLine}Line 2{Environment.NewLine}Line 3";

Adding a column to an existing table in a Rails migration

Sometimes rails generate migration add_email_to_users email:string produces a migration like this

class AddEmailToUsers < ActiveRecord::Migration[5.0]
  def change

In that case you have to manually an add_column to change:

class AddEmailToUsers < ActiveRecord::Migration[5.0]
  def change
    add_column :users, :email, :string

And then run rake db:migrate

Creating Accordion Table with Bootstrap

This seems to be already asked before:

This might help:

Twitter Bootstrap Use collapse.js on table cells [Almost Done]


Your fiddle wasn't loading jQuery, so anything worked.

<table class="table table-hover">

    <tr data-toggle="collapse" data-target="#accordion" class="clickable">
        <td>Some Stuff</td>
        <td>Some more stuff</td>
        <td>And some more</td>
        <td colspan="3">
            <div id="accordion" class="collapse">Hidden by default</div>

Try this one:

I also added colspan='2' to the details row. But it's essentially your fiddle with jQuery loaded (in frameworks in the left column)

How do I use a 32-bit ODBC driver on 64-bit Server 2008 when the installer doesn't create a standard DSN?

A lot of these answers are pretty old, so I thought I would update with a solution that I think is helpful.

Our issue was similar to OP's, we upgraded 32 bit XP machines to 64 bit windows 7 and our application software that uses a 32 bit ODBC driver stopped being able to write to our database.

Turns out, there are two ODBC Data Source Managers, one for 32 bit and one for 64 bit. So I had to run the 32 bit version which is found in C:\Windows\SysWOW64\odbcad32.exe. Inside the ODBC Data Source Manager, I was able to go to the System DSN tab and Add my driver to the list using the Add button. (You can check the Drivers tab to see a list of the drivers you can add, if your driver isn't in this list then you may need to install it).

The next issue was the software that we ran was compiled to use 'Any CPU'. This would see the operating system was 64 bit, so it would look at the 64 bit ODBC Data Sources. So I had to force the program to compile as an x86 program, which then tells it to look at the 32 bit ODBC Data Sources. To set your program to x86, in Visual Studio go to your project properties and under the build tab at the top there is a platform drop down list, and choose x86. If you don't have the source code and can't compile the program as x86, you might be able to right click the program .exe and go to the compatibility tab and choose a compatibility that works for you.

Once I had the drivers added and the program pointing to the right drivers, everything worked like it use to. Hopefully this helps anyone working with older software.

Android basics: running code in the UI thread

None of those are precisely the same, though they will all have the same net effect.

The difference between the first and the second is that if you happen to be on the main application thread when executing the code, the first one (runOnUiThread()) will execute the Runnable immediately. The second one (post()) always puts the Runnable at the end of the event queue, even if you are already on the main application thread.

The third one, assuming you create and execute an instance of BackgroundTask, will waste a lot of time grabbing a thread out of the thread pool, to execute a default no-op doInBackground(), before eventually doing what amounts to a post(). This is by far the least efficient of the three. Use AsyncTask if you actually have work to do in a background thread, not just for the use of onPostExecute().

base_url() function not working in codeigniter

Question -I wanted to load my css file but it was not working even though i autoload and manual laod why ? i found the solution => here is my solution : application>config>config.php $config['base_url'] = 'http://localhost/CodeIgniter/'; //paste the link to base url

question explanation:

" > i had my bootstrap.min.css file inside assets/css folder where assets is root directory which i was created.But it was not working even though when i loaded ? 1. $autoload['helper'] = array('url'); 2. $this->load->helper('url'); in my controllar then i go to my no protocol

The documentation could help you :

The method DocumentBuilder.parse(String) takes a URI and tries to open it. If you want to directly give the content, you have to give it an InputStream or Reader, for example a StringReader. ... Welcome to the Java standard levels of indirections !

Basically :

DocumentBuilder db = ...;
String xml = ...;
db.parse(new InputSource(new StringReader(xml)));

Note that if you read your XML from a file, you can directly give the File object to DocumentBuilder.parse() .

As a side note, this is a pattern you will encounter a lot in Java. Usually, most API work with Streams more than with Strings. Using Streams means that potentially not all the content has to be loaded in memory at the same time, which can be a great idea !

Bootstrap Modal sitting behind backdrop

If you use JQuery, you can use the appendTo() to append the modal to a specific element, in this case, the , in most case, a simple one line can move your modal on top of the backdrop regardless where your modal div's position


here's the reference of the JQuery appendTo function:

I updated it to your fiddle

How to convert JSON string to array

Make sure that the string is in the following JSON format which is something like this:

{"result":"success","testid":"1"} (with " ") .

If not, then you can add "responsetype => json" in your request params.

Then use json_decode($response,true) to convert it into an array.

How to convert hex string to Java string?

Using Hex in Apache Commons:

String hexString = "fd00000aa8660b5b010006acdc0100000101000100010000";    
byte[] bytes = Hex.decodeHex(hexString.toCharArray());
System.out.println(new String(bytes, "UTF-8"));

Difference between List, List<?>, List<T>, List<E>, and List<Object>

In your third point, "T" cannot be resolved because its not declared, usually when you declare a generic class you can use "T" as the name of the bound type parameter, many online examples including oracle's tutorials use "T" as the name of the type parameter, say for example, you declare a class like:

public class FooHandler<T>
   public void operateOnFoo(T foo) { /*some foo handling code here*/}


you are saying that FooHandler's operateOnFoo method expects a variable of type "T" which is declared on the class declaration itself, with this in mind, you can later add another method like

public void operateOnFoos(List<T> foos)

in all the cases either T, E or U there all identifiers of the type parameter, you can even have more than one type parameter which uses the syntax

public class MyClass<Atype,AnotherType> {}

in your forth ponint although efectively Sting is a sub type of Object, in generics classes there is no such relation, List<String> is not a sub type of List<Object> they are two diferent types from the compiler point of view, this is best explained in this blog entry

Size of Matrix OpenCV

If you are using the Python wrappers, then (assuming your matrix name is mat):

  • mat.shape gives you an array of the type- [height, width, channels]

  • mat.size gives you the size of the array

Sample Code:

import cv2
mat = cv2.imread('sample.png')
height, width, channel = mat.shape[:3]
size = mat.size

Import pfx file into particular certificate store from command line

With Windows 2012 R2 (Win 8.1) and up, you also have the "official" Import-PfxCertificate cmdlet

Here are some essential parts of code (an adaptable example):

Invoke-Command -ComputerName $Computer -ScriptBlock {
            [string] $CertFileName,
            [string] $CertRootStore,
            [string] $CertStore,
            [string] $X509Flags,
        $CertPath = "$Env:SystemRoot\$CertFileName"
        $Pfx = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2
        # Flags to send in are documented here:
        $Pfx.Import($CertPath, $PfxPass, $X509Flags) #"Exportable,PersistKeySet")
        $Store = New-Object -TypeName System.Security.Cryptography.X509Certificates.X509Store -ArgumentList $CertStore, $CertRootStore
        if ($?)
            "${Env:ComputerName}: Successfully added certificate."
            "${Env:ComputerName}: Failed to add certificate! $($Error[0].ToString() -replace '[\r\n]+', ' ')"
        Remove-Item -LiteralPath $CertPath
    } -ArgumentList $TempCertFileName, $CertRootStore, $CertStore, $X509Flags, $Password

Based on mao47's code and some research, I wrote up a little article and a simple cmdlet for importing/pushing PFX certificates to remote computers.

Here's my article with more details and complete code that also works with PSv2 (default on Server 2008 R2 / Windows 7), so long as you have SMB enabled and administrative share access.

What are best practices that you use when writing Objective-C and Cocoa?

Sort strings as the user wants

When you sort strings to present to the user, you should not use the simple compare: method. Instead, you should always use localized comparison methods such as localizedCompare: or localizedCaseInsensitiveCompare:.

For more details, see Searching, Comparing, and Sorting Strings.

Should a RESTful 'PUT' operation return something

I used RESTful API in my services, and here is my opinion: First we must get to a common view: PUT is used to update an resource not create or get.

I defined resources with: Stateless resource and Stateful resource:

  • Stateless resources For these resources, just return the HttpCode with empty body, it's enough.

  • Stateful resources For example: the resource's version. For this kind of resources, you must provide the version when you want to change it, so return the full resource or return the version to the client, so the client need't to send a get request after the update action.

But, for a service or system, keep it simple, clearly, easy to use and maintain is the most important thing.

Error: getaddrinfo ENOTFOUND in nodejs for get call

Struggling for hours, couldn't afford for more.

The solution that worked for me in less than 3 minutes was:

npm install axios

Code ended up even shorter:

const url = `${this.env.someMicroservice.address}/v1/my-end-point`;

const { data } = await axios.get<MyInterface[]>(url, {
  auth: {
    username: this.env.auth.user,
    password: this.env.auth.pass

return data;

Bash script to check running process

I found the problem. ps -ae instead ps -a works.

I guess it has to do with my rights in the shared hosting environment. There's apparently a difference between executing "ps -a" from the command line and executing it from within a bash-script.

How can I use UIColorFromRGB in Swift?

You can use this:

//The color RGB #85CC4B
let newColor = UIColor(red: CGFloat(0x85)/255
                      ,green: CGFloat(0xCC)/255
                      ,blue: CGFloat(0x4B)/255
                      ,alpha: 1.0)

this is error ORA-12154: TNS:could not resolve the connect identifier specified?

ORA-12154: TNS:could not resolve the connect identifier specified?

In case the TNS is not defined you can also try this one:

If you are using 2010 or other version of VS and oracle 10g express edition or lower version, and you make a connection string like this:

static string constr = @"Data Source=(DESCRIPTION=
    (ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=yourhostname )(PORT=1521)))
    User Id=system ;Password=yourpasswrd"; 

After that you get error message ORA-12154: TNS:could not resolve the connect identifier specified then first you have to do restart your system and run your project.

And if Your windows is 64 bit then you need to install oracle 11g 32 bit and if you installed 11g 64 bit then you need to Install Oracle 11g Oracle Data Access Components (ODAC) with Oracle Developer Tools for Visual Studio version or later from OTN and check it in Oracle Universal Installer Please be sure that the following are checked:

Oracle Data Provider for .NET 2.0

Oracle Providers for ASP.NET

Oracle Developer Tools for Visual Studio

Oracle Instant Client 

And then restart your Visual Studio and then run your project .... NOTE:- SYSTEM RESTART IS necessary TO SOLVE THIS TYPES OF ERROR.......