Programs & Examples On #Ibm jdk

Avoid duplicates in INSERT INTO SELECT query in SQL Server


  (id, name)
                    FROM TABLE_2 t2
                   WHERE =

Using NOT IN:

  (id, name)
                       FROM TABLE_2)


  (id, name)

     FROM TABLE_1 t1

Of the three options, the LEFT JOIN/IS NULL is less efficient. See this link for more details.

How do I use the CONCAT function in SQL Server 2008 R2?

(city + ', ' + state + ' ' + zip) as ctstzip for select
(city + ', ' + state + ' ' + zip) for insert

Only cast or convert if any field type is different from others.

On insert the value needs to be in the correct spot you need it be inserted. Using "as" will give you an error.


Insert into testtable (ctstzip) Values ((city + ', ' + state + ' ' + zip))

HTML email with Javascript

What you are trying to achieve should be done in the web browser because javascript simply doesn't work with html email design. The various email clients that are out there e.g. gmail, outlook, yahoo strip scripts put of the code for security reasons.

It is best to just use HTML and CSS to style your emails. Maybe you could have a call to action (cta) in your html email that sends the user to a web page with your expanding and collapsing content feature.

Fatal error: Call to a member function bind_param() on boolean

This particular error has very little to do with the actual error. Here is my similar experience and the solution...

I had a table that I use in my statement with |database-name|.login composite name. I thought this wouldn't be a problem. It was the problem indeed. Enclosing it inside square brackets solved my problem ([|database-name|].[login]). So, the problem is MySQL preserved words (other way around)... make sure your columns too are not failing to this type of error scenario...

Read files from a Folder present in project

If you need to get all the files in the folder named 'Data', just code it as below

string[] Documents = System.IO.Directory.GetFiles("../../Data/");

Now the 'Documents' consists of array of complete object name of two text files in the 'Data' folder 'Data'.

Change New Google Recaptcha (v2) Width

    -webkit-transform-origin:0 0;
    filter: progid:DXImageTransform.Microsoft.Matrix(M11=1.1,M12=0,M21=0,M22=1.1,SizingMethod='auto expand');

Oracle Installer:[INS-13001] Environment does not meet minimum requirements

its awful oracle installer:


I got it as I used MY_PC as NETBIOS name instead of MYPC (Underscore is bad for it..)

Can be an historical reason.. but message is obscure.

How can I create a product key for my C# application?

If you are asking about the keys that you can type in, like Windows product keys, then they are based on some checks. If you are talking about the keys that you have to copy paste, then they are based on a digitial signature (private key encryption).

A simple product key logic could be to start with saying that the product key consists of four 5-digit groups, like abcde-fghij-kljmo-pqrst, and then go on to specify internal relationships like f+k+p should equal a, meaning the first digits of the 2, 3 and 4 group should total to a. This means that 8xxxx-2xxxx-4xxxx-2xxxx is valid, so is 8xxxx-1xxxx-0xxxx-7xxxx. Of course, there would be other relationships as well, including complex relations like, if the second digit of the first group is odd, then the last digit of the last group should be odd too. This way there would be generators for product keys and verification of product keys would simply check if it matches all the rules.

Encryption are normally the string of information about the license encrypted using a private key (== digitally signed) and converted to Base64. The public key is distributed with the application. When the Base64 string arrives, it is verified (==decrypted) by the public key and if found valid, the product is activated.

javascript toISOString() ignores timezone offset

Moment js solution to this is

var d = new Date(new Date().setHours(0,0,0,0));
m.add(m.utcOffset(), 'm')
// output "2019-07-18T00:00:00.000Z"

How can I verify if an AD account is locked?

If you want to check via command line , then use command "net user username /DOMAIN"

enter image description here

Disable browser cache for entire ASP.NET website

You may want to disable browser caching for all pages rendered by controllers (i.e. HTML pages), but keep caching in place for resources such as scripts, style sheets, and images. If you're using MVC4+ bundling and minification, you'll want to keep the default cache durations for scripts and stylesheets (very long durations, since the cache gets invalidated based on a change to a unique URL, not based on time).

In MVC4+, to disable browser caching across all controllers, but retain it for anything not served by a controller, add this to FilterConfig.RegisterGlobalFilters:

filters.Add(new DisableCache());

Define DisableCache as follows:

class DisableCache : ActionFilterAttribute
    public override void OnResultExecuting(ResultExecutingContext filterContext)

Selenium Webdriver move mouse to Point

If you are using a RemoteWebDriver, you can cast WebElement into RemoteWebElement. You can then call getCoordinates() on that object to get the coordinates.

        WebElement el = driver.findElementById("elementId");
        Coordinates c = ((RemoteWebElement)el).getCoordinates();

Opening a new tab to read a PDF file

On Chrome this has proven to work well for me.

<a href="newsletter_01.pdf" target="_new">Read more</a>

How do I use a custom deleter with a std::unique_ptr member?

You can simply use std::bind with a your destroy function.

std::unique_ptr<Bar, std::function<void(Bar*)>> bar(create(), std::bind(&destroy,

But of course you can also use a lambda.

std::unique_ptr<Bar, std::function<void(Bar*)>> ptr(create(), [](Bar* b){ destroy(b);});

How do I do pagination in ASP.NET MVC?

public ActionResult Paging(int? pageno,bool? fwd,bool? bwd)        
       Session["currentpage"] = pageno;

    using (HatronEntities DB = new HatronEntities())
        if(fwd!=null && (bool)fwd)
            pageno = Convert.ToInt32(Session["currentpage"]) + 1;
            Session["currentpage"] = pageno;
        if (bwd != null && (bool)bwd)
            pageno = Convert.ToInt32(Session["currentpage"]) - 1;
            Session["currentpage"] = pageno;
        if (pageno==null)
            pageno = 1;
            pageno = 1;
        int total = DB.EmployeePromotion(0, 0, 0).Count();
        int  totalPage = (int)Math.Ceiling((double)total / 20);
        ViewBag.pages = totalPage;
        if (pageno > totalPage)
            pageno = totalPage;
        return View (DB.EmployeePromotion(0,0,0).Skip(GetSkip((int)pageno,20)).Take(20).ToList());     

private static int GetSkip(int pageIndex, int take)
    return (pageIndex - 1) * take;

@model IEnumerable<EmployeePromotion_Result>
  Layout = null;

 <!DOCTYPE html>

    <meta name="viewport" content="width=device-width" />
    <table border="1">
        @foreach (var itm in Model)
    <a href="@Url.Action("Paging", "Home",new { pageno=1 })">First  page</a> 
    <a href="@Url.Action("Paging", "Home", new { bwd =true })"><<</a> 
    @for(int itmp =1; itmp< Convert.ToInt32(ViewBag.pages)+1;itmp++)
       <a href="@Url.Action("Paging", "Home",new { pageno=itmp   })">@itmp.ToString()</a>
    <a href="@Url.Action("Paging", "Home", new { fwd = true })">>></a> 
    <a href="@Url.Action("Paging", "Home", new { pageno =                                                                               Convert.ToInt32(ViewBag.pages) })">Last page</a> 

Oracle DB: How can I write query ignoring case?

Use ALTER SESSION statements to set comparison to case-insensitive:

alter session set NLS_COMP=LINGUISTIC;
alter session set NLS_SORT=BINARY_CI;

If you're still using version 10gR2, use the below statements. See this FAQ for details.

alter session set NLS_COMP=ANSI;
alter session set NLS_SORT=BINARY_CI;

How can I turn a List of Lists into a List in Java 8?

You can use flatMap to flatten the internal lists (after converting them to Streams) into a single Stream, and then collect the result into a list:

List<List<Object>> list = ...
List<Object> flat =

Hibernate Error: org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session

Are your Id mappings correct? If the database is responsible for creating the Id through an identifier, you need to map your userobject to that ..

How to get just numeric part of CSS property with jQuery?

Should remove units while preserving decimals.

var regExp = new RegExp("[a-z][A-Z]","g");
parseFloat($(this).css("property").replace(regExp, ""));

Fastest way to count number of occurrences in a Python list

By the use of Counter dictionary counting the occurrences of all element as well as most common element in python list with its occurrence value in most efficient way.

If our python list is:-

l=['1', '1', '1', '1', '1', '1', '2', '2', '2', '2', '7', '7', '7', '10', '10']

To find occurrence of every items in the python list use following:-

\>>from collections import Counter


\>>print c

Counter({'1': 6, '2': 4, '7': 3, '10': 2})

To find most/highest occurrence of items in the python list:-



[('1', 6), ('2', 4), ('7', 3), ('10', 2)]

For Highest one:-



For the item just use k[0][0]



For nth highest item and its no of occurrence in the list use follow:-

**for n=2 **

\>>print k[n-1][0] # For item


\>>print k[n-1][1] # For value


What is null in Java?

There are two major categories of types in Java: primitive and reference. Variables declared of a primitive type store values; variables declared of a reference type store references.

String x = null;

In this case, the initialization statement declares a variables “x”. “x” stores String reference. It is null here. First of all, null is not a valid object instance, so there is no memory allocated for it. It is simply a value that indicates that the object reference is not currently referring to an object.

Get screen width and height in Android

Two steps. First, extend Activity class

class Example extends Activity

Second: Use this code

 DisplayMetrics displayMetrics = new DisplayMetrics();
 WindowManager windowmanager = (WindowManager) getApplicationContext().getSystemService(Context.WINDOW_SERVICE);
 int deviceWidth = displayMetrics.widthPixels;
 int deviceHeight = displayMetrics.heightPixels;

How to use the 'main' parameter in package.json?

From the npm documentation:

The main field is a module ID that is the primary entry point to your program. That is, if your package is named foo, and a user installs it, and then does require("foo"), then your main module's exports object will be returned.

This should be a module ID relative to the root of your package folder.

For most modules, it makes the most sense to have a main script and often not much else.

To put it short:

  1. You only need a main parameter in your package.json if the entry point to your package differs from index.js in its root folder. For example, people often put the entry point to lib/index.js or lib/<packagename>.js, in this case the corresponding script must be described as main in package.json.
  2. You can't have two scripts as main, simply because the entry point require('yourpackagename') must be defined unambiguously.

linking jquery in html

In this case, your test.js will not run, because you're loading it before jQuery. put it after jQuery:

<script src=""></script>
<script src=""></script>
<script type="text/javascript" src="test.js"></script>

onKeyDown event not working on divs in React

You need to write it this way

    style={{ position: "absolute" }}

If onKeyPressed is not bound to this, then try to rewrite it using arrow function or bind it in the component constructor.

How to get the date and time values in a C program?

The answers given above are good CRT answers, but if you want you can also use the Win32 solution to this. It's almost identical but IMO if you're programming for Windows you might as well just use its API (although I don't know if you are programming in Windows).

char* arrDayNames[7] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"}; 
GetLocalTime(&st); // Alternatively use GetSystemTime for the UTC version of the time
printf("The current date and time are: %d/%d/%d %d:%d:%d:%d", st.wDay, st.wMonth, st.wYear, st.wHour, st.wMinute, st.wSecond, st.wMilliseconds);
printf("The day is: %s", arrDayNames[st.wDayOfWeek]);

Anyway, this is a Windows solution. I hope it will be helpful for you sometime!

How to change Maven local repository in eclipse

Here is settings.xml --> C:\maven\conf\settings.xml

Appending a line to a file only if it does not already exist

This would be a clean, readable and reusable solution using grep and echo to add a line to a file only if it doesn't already exist:

LINE='include "/configs/projectname.conf"'
grep -qF -- "$LINE" "$FILE" || echo "$LINE" >> "$FILE"

If you need to match the whole line use grep -xqF

Add -s to ignore errors when the file does not exist, creating a new file with just that line.

update listview dynamically with adapter

add and remove methods are easier to use. They update the data in the list and call notifyDataSetChanged in background.

Sample code:

adapter.add("your object");
adapter.remove("your object");

Check whether variable is number or string in JavaScript

Best way to do that is using isNaN + type casting:

Updated all-in method:

function isNumber(n) { return !isNaN(parseFloat(n)) && !isNaN(n - 0) }

The same using regex:

function isNumber(n) { return /^-?[\d.]+(?:e-?\d+)?$/.test(n); } 


isNumber('123'); // true  
isNumber('123abc'); // false  
isNumber(5); // true  
isNumber('q345'); // false
isNumber(null); // false
isNumber(undefined); // false
isNumber(false); // false
isNumber('   '); // false

Get last 3 characters of string

Many ways this can be achieved.

Simple approach should be taking Substring of an input string.

var result = input.Substring(input.Length - 3);

Another approach using Regular Expression to extract last 3 characters.

var result = Regex.Match(input,@"(.{3})\s*$");

Working Demo

Failing to run jar file from command line: “no main manifest attribute”

Try to run

java -cp ScrumTimeCaptureMaintenence.jar Main

Need to make a clickable <div> button

Just use an <a> by itself, set it to display: block; and set width and height. Get rid of the <span> and <div>. This is the semantic way to do it. There is no need to wrap things in <divs> (or any element) for layout. That is what CSS is for.



<a id="music" href="Music.html">Music I Like</a>


#music {
    background-color: black;
    color: white;
    display: block;
    height: 40px;
    line-height: 40px;
    text-decoration: none;
    width: 100px;
    text-align: center;


enter image description here

How to increase heap size for jBoss server

Use -Xms and -Xmx command line options when runing java:

-Xms<size>        set initial Java heap size
-Xmx<size>        set maximum Java heap size

For more help type java -X in command line.

<meta charset="utf-8"> vs <meta http-equiv="Content-Type">

In HTML5, they are equivalent. Use the shorter one, it is easier to remember and type. Browser support is fine since it was designed for backwards compatibility.

Python: split a list based on a condition?

good.append(x) if x in goodvals else bad.append(x)

This elegant and concise answer by @dansalmo showed up buried in the comments, so I'm just reposting it here as an answer so it can get the prominence it deserves, especially for new readers.

Complete example:

good, bad = [], []
for x in my_list:
    good.append(x) if x in goodvals else bad.append(x)

How can I pass a parameter to a t-sql script?

SQL*Plus uses &1, &2... &n to access the parameters.

Suppose you have the following script test.sql:

SPOOL test.log
EXEC dbms_output.put_line('&1 &2');

you could call this script like this for example:

$ sqlplus login/pw @test Hello World!


In a UNIX script you would usually call a SQL script like this:

sqlplus /nolog << EOF
connect user/password@db
@test.sql Hello World!

so that your login/password won't be visible with another session's ps

Bootstrap button - remove outline on Chrome OS X

I see .btn:focus has an outline on it:

.btn:focus {
  outline: thin dotted;
  outline: 5px auto -webkit-focus-ring-color;
  outline-offset: -2px;

Try changing this to:

.btn:focus {
  outline: none !important;

Basically, look for any instances of outline on :focused elements — that's what's causing it.

Update - For Bootstrap v4:

.btn:focus {
  box-shadow: none;

Int to Decimal Conversion - Insert decimal point at specified location

Simple math.

double result = ((double)number) / 100.0;

Although you may want to use decimal rather than double: decimal vs double! - Which one should I use and when?

Master Page Weirdness - "Content controls have to be top-level controls in a content page or a nested master page that references a master page."

I just encountered this exception and in my case it was cause by a white space between asp:content elements

So, this failed:

<asp:content runat="server" ContentPlaceHolderID="Header">

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

But removing the white spaces between the elements worked:

<asp:content runat="server" ContentPlaceHolderID="Header">
</asp:content><asp:Content runat="server" ContentPlaceHolderID="Content">

How to stop process from .BAT file?

As TASKKILL might be unavailable on some Home/basic editions of windows here some alternatives:

TSKILL processName



Have on mind that processName should not have the .exe suffix and is limited to 18 characters.

Another option is WMIC :

wmic Path win32_process Where "Caption Like 'MyProcess.exe'" Call Terminate

wmic offer even more flexibility than taskkill .With wmic Path win32_process get you can see the available fileds you can filter.

How do I parse JSON with Objective-C?

Don't reinvent the wheel. Use json-framework or something similar.

If you do decide to use json-framework, here's how you would parse a JSON string into an NSDictionary:

SBJsonParser* parser = [[[SBJsonParser alloc] init] autorelease];
// assuming jsonString is your JSON string...
NSDictionary* myDict = [parser objectWithString:jsonString];

// now you can grab data out of the dictionary using objectForKey or another dictionary method

URL string format for connecting to Oracle database with JDBC

String host = <host name>
String port = <port>
String service = <service name>
String dbName = <db schema>+"."+service
String url = "jdbc:oracle:thin:@"+host+":"+"port"+"/"+dbName

How to wrap text in LaTeX tables?

 \caption{ Example of force text wrap}
   cell 1       &   cell 2 \\   \hline
   cell 3                &       cell 4 & & very big line that needs to be wrap. \\ \hline
   cell 5       &   cell 6 \\   \hline

MySQL InnoDB not releasing disk space after deleting data rows from table

If you don't use innodb_file_per_table, reclaiming disk space is possible, but quite tedious, and requires a significant amount of downtime.

The How To is pretty in-depth - but I pasted the relevant part below.

Be sure to also retain a copy of your schema in your dump.

Currently, you cannot remove a data file from the system tablespace. To decrease the system tablespace size, use this procedure:

Use mysqldump to dump all your InnoDB tables.

Stop the server.

Remove all the existing tablespace files, including the ibdata and ib_log files. If you want to keep a backup copy of the information, then copy all the ib* files to another location before the removing the files in your MySQL installation.

Remove any .frm files for InnoDB tables.

Configure a new tablespace.

Restart the server.

Import the dump files.

Why does C++ compilation take so long?

C++ is compiled into machine code. So you have the pre-processor, the compiler, the optimizer, and finally the assembler, all of which have to run.

Java and C# are compiled into byte-code/IL, and the Java virtual machine/.NET Framework execute (or JIT compile into machine code) prior to execution.

Python is an interpreted language that is also compiled into byte-code.

I'm sure there are other reasons for this as well, but in general, not having to compile to native machine language saves time.

How to convert data.frame column from Factor to numeric

This is FAQ 7.10. Others have shown how to apply this to a single column in a data frame, or to multiple columns in a data frame. But this is really treating the symptom, not curing the cause.

A better approach is to use the colClasses argument to read.table and related functions to tell R that the column should be numeric so that it never creates a factor and creates numeric. This will put in NA for any values that do not convert to numeric.

Another better option is to figure out why R does not recognize the column as numeric (usually a non numeric character somewhere in that column) and fix the original data so that it is read in properly without needing to create NAs.

Best is a combination of the last 2, make sure the data is correct before reading it in and specify colClasses so R does not need to guess (this can speed up reading as well).

Nginx fails to load css files

I was having the same issue and none of the above made any difference for me what did work was having my location php above any other location blocks.

location ~ [^/]\.php(/|$) {
fastcgi_split_path_info  ^(.+\.php)(/.+)$;
fastcgi_index            index.php;
fastcgi_pass             unix:/var/run/php/php7.3-fpm.sock;
include                  fastcgi_params;
fastcgi_param   PATH_INFO       $fastcgi_path_info;
fastcgi_param   SCRIPT_FILENAME $document_root$fastcgi_script_name;
** The below is specifically for moodle **
location /dataroot/ {
alias <full_moodledata_path>; # ensure the path ends with /

Accessing items in an collections.OrderedDict by index

It's a new era and with Python 3.6.1 dictionaries now retain their order. These semantics aren't explicit because that would require BDFL approval. But Raymond Hettinger is the next best thing (and funnier) and he makes a pretty strong case that dictionaries will be ordered for a very long time.

So now it's easy to create slices of a dictionary:

test_dict = {
                'first':  1,
                'second': 2,
                'third':  3,
                'fourth': 4


Note: Dictonary insertion-order preservation is now official in Python 3.7.

Fastest way to remove first char in a String

I know this is hyper-optimization land, but it seemed like a good excuse to kick the wheels of BenchmarkDotNet. The result of this test (on .NET Core even) is that Substring is ever so slightly faster than Remove, in this sample test: 19.37ns vs 22.52ns for Remove. So some ~16% faster.

using System;
using BenchmarkDotNet.Attributes;

namespace BenchmarkFun
    public class StringSubstringVsRemove
        public readonly string SampleString = " My name is Daffy Duck.";

        public string StringSubstring() => SampleString.Substring(1);

        public string StringRemove() => SampleString.Remove(0, 1);

        public void AssertTestIsValid()
            string subsRes = StringSubstring();
            string remvRes = StringRemove();

            if (subsRes == null
                || subsRes.Length != SampleString.Length - 1
                || subsRes != remvRes) {
                throw new Exception("INVALID TEST!");

    class Program
        static void Main()
            // let's make sure test results are really equal / valid
            new StringSubstringVsRemove().AssertTestIsValid();

            var summary = BenchmarkRunner.Run<StringSubstringVsRemove>();


BenchmarkDotNet=v0.11.4, OS=Windows 10.0.17763.253 (1809/October2018Update/Redstone5)
Intel Core i7-6700HQ CPU 2.60GHz (Skylake), 1 CPU, 8 logical and 4 physical cores
.NET Core SDK=3.0.100-preview-010184
  [Host]     : .NET Core 3.0.0-preview-27324-5 (CoreCLR 4.6.27322.0, CoreFX, 64bit RyuJIT
  DefaultJob : .NET Core 3.0.0-preview-27324-5 (CoreCLR 4.6.27322.0, CoreFX, 64bit RyuJIT

|          Method |     Mean |     Error |    StdDev |
|---------------- |---------:|----------:|----------:|
| StringSubstring | 19.37 ns | 0.3940 ns | 0.3493 ns |
|    StringRemove | 22.52 ns | 0.4062 ns | 0.3601 ns |

Difference between `Optional.orElse()` and `Optional.orElseGet()`

Take these two scenarios:

Optional<Foo> opt = ...
Foo x = opt.orElse( new Foo() );
Foo y = opt.orElseGet( Foo::new );

If opt doesn't contain a value, the two are indeed equivalent. But if opt does contain a value, how many Foo objects will be created?

P.s.: of course in this example the difference probably wouldn't be measurable, but if you have to obtain your default value from a remote web service for example, or from a database, it suddenly becomes very important.

Positive Number to Negative Number in JavaScript?

The reverse of abs is Math.abs(num) * -1.

Change Bootstrap input focus blue glow

For the input border before the focus. You can specify your favorite color you want to use and other css like padding etc

.input {
    padding: 6px 190px 6px 15px;
    outline: #2a65ea auto 105px ;

When we focus on input. You can specify your favorite color outline you wish

    box-shadow: none;
    border-color: none;
    outline: lightgreen auto 5px ;

CSS selector for disabled input type="submit"

Does that work in IE6?

No, IE6 does not support attribute selectors at all, cf. CSS Compatibility and Internet Explorer.

You might find How to workaround: IE6 does not support CSS “attribute” selectors worth the read.

If you are to ignore IE6, you could do (CSS2.1):

button[disabled=disabled] {

CSS3 (IE9+):

button:disabled {

You can substitute [disabled=disabled] (attribute value) with [disabled] (attribute presence).

Checking if a key exists in a JavaScript object?

Here's a helper function I find quite useful

This keyExists(key, search) can be used to easily lookup a key within objects or arrays!

Just pass it the key you want to find, and search obj (the object or array) you want to find it in.

function keyExists(key, search) {_x000D_
        if (!search || (search.constructor !== Array && search.constructor !== Object)) {_x000D_
            return false;_x000D_
        for (var i = 0; i < search.length; i++) {_x000D_
            if (search[i] === key) {_x000D_
                return true;_x000D_
        return key in search;_x000D_
// How to use it:_x000D_
// Searching for keys in Arrays_x000D_
console.log(keyExists('apple', ['apple', 'banana', 'orange'])); // true_x000D_
console.log(keyExists('fruit', ['apple', 'banana', 'orange'])); // false_x000D_
// Searching for keys in Objects_x000D_
console.log(keyExists('age', {'name': 'Bill', 'age': 29 })); // true_x000D_
console.log(keyExists('title', {'name': 'Jason', 'age': 29 })); // false

It's been pretty reliable and works well cross-browser.

Setting Django up to use MySQL

Run these commands

sudo apt-get install python-dev python3-dev
sudo apt-get install libmysqlclient-dev
pip install MySQL-python 
pip install pymysql
pip install mysqlclient

Then configure like

    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'django_db',
        'HOST': '',
        'PORT': '3306',
        'USER': 'root',
        'PASSWORD': '123456',

Enjoy mysql connection

How to Consolidate Data from Multiple Excel Columns All into One Column

The formula


placed into each cell of your second workbook will retrieve the appropriate cell from the source sheet. No macros, simple copying from one sheet to another to reformat the results.

You will need to modify the ranges in the COUNT function to match the maximum number of rows in the source sheet. Adjust for column headers as required.

If you need something other than a 0 for empty cells, you may prefer to include a conditional.

A script to reformat the data may well be more efficient, but 20k rows is no longer a real limit in a modern Excel workbook.

Cannot insert explicit value for identity column in table 'table' when IDENTITY_INSERT is set to OFF

You're inserting values for OperationId that is an identity column.

You can turn on identity insert on the table like this so that you can specify your own identity values.


/*Note the column list is REQUIRED here, not optional*/
VALUES      (20,
             'Hierachy Update',


org.hibernate.MappingException: Unknown entity

you should add all the entity files in the .addAnnotatedClass(Class) method, if the class needs to be auto discovered.

use this link, it might help..

Could not load file or assembly 'Microsoft.ReportViewer.Common, Version=

I Had the same problem.

The solution for me is:

You must have the same version of: Microsoft.ReportViewer.ProcessingObjectModel registred in C:\Windows\assembly\GAC_MSIL\Microsoft.ReportViewer.ProcessingObjectModel, like you have registraded in web.config in developer server:

enter image description here

In my case i was only registred the 13. version in my prodution server and i have the 12. version in developer server.

the solution is install the version 12. in the prodution server too

the version 12. :

Then now i have the version 12. in the prodution and the report work fine.

*** Remember to reset your IIS after instalation

enter image description here

How can I set the aspect ratio in matplotlib?

This answer is based on Yann's answer. It will set the aspect ratio for linear or log-log plots. I've used additional information from to test if the axes are log-scale.

def forceAspect(ax,aspect=1):
    #aspect is width/height
    scale_str = ax.get_yaxis().get_scale()
    xmin,xmax = ax.get_xlim()
    ymin,ymax = ax.get_ylim()
    if scale_str=='linear':
        asp = abs((xmax-xmin)/(ymax-ymin))/aspect
    elif scale_str=='log':
        asp = abs((scipy.log(xmax)-scipy.log(xmin))/(scipy.log(ymax)-scipy.log(ymin)))/aspect

Obviously you can use any version of log you want, I've used scipy, but numpy or math should be fine.

How to empty a char array?


  memset(members, 0, 255);

in general

  memset(members, 0, sizeof members);

if the array is in scope, or

  memset(members, 0, nMembers * (sizeof members[0]) );

if you only have the pointer value, and nMembers is the number of elements in the array.

EDIT Of course, now the requirement has changed from the generic task of clearing an array to purely resetting a string, memset is overkill and just zeroing the first element suffices (as noted in other answers).

EDIT In order to use memset, you have to include string.h.

Getting rid of bullet points from <ul>

I had an identical problem.

The solution was that the bullet was added via a background image, NOT via list-style-type. A quick 'background: none' and Bob's your uncle!

What is $@ in Bash?

Just from reading that i would have never understood that "$@" expands into a list of separate parameters. Whereas, "$*" is one parameter consisting of all the parameters added together.

If it still makes no sense do this.

CardView background color always white

You can use




Replacing NULL with 0 in a SQL server query

Use COALESCE, which returns the first not-null value e.g.

SELECT COALESCE(sum(case when c.runstatus = 'Succeeded' then 1 end), 0) as Succeeded

Will set Succeeded as 0 if it is returned as NULL.

Python NoneType object is not callable (beginner)

I faced the error "TypeError: 'NoneType' object is not callable " but for a different issue. With the above clues, i was able to debug and got it right! The issue that i faced was : I had the custome Library written and my file wasnt recognizing it although i had mentioned it

Library           ../../../libraries/customlibraries/
the keywords from my custom library were recognized and that error  was resolved only after specifying the complete path, as it was not getting the callable function.

django order_by query set, ascending and descending

for ascending order:


for descending order:

1.  Reserved.objects.filter(client=client_id).order_by('-check_in')


2.  Reserved.objects.filter(client=client_id).order_by('check_in')[::-1]

Attach parameter to button.addTarget action in Swift

If you have a loop of buttons like me you can try something like this

var buttonTags:[Int:String]? // can be [Int:Any]
let myArray = [0:"a",1:"b"]
for (index,value) in myArray {

     let button = // Create a button

     buttonTags?[index] = myArray[index]
     button.tag = index
     button.addTarget(self, action: #selector(buttonAction(_:)), for: .touchDown)

@objc func buttonAction(_ sender:UIButton) {

    let myString = buttonTags[sender.tag]


Execute a batch file on a remote PC using a batch file on local PC

You can use WMIC or SCHTASKS (which means no third party software is needed):


SCHTASKS /s remote_machine /U username /P password /create /tn "On demand demo" /tr "C:\some.bat" /sc ONCE /sd 01/01/1910 /st 00:00
SCHTASKS /s remote_machine /U username /P password /run /TN "On demand demo" 

2) WMIC (wmic will return the pid of the started process)

WMIC /NODE:"remote_machine" /user user /password password process call create "c:\some.bat","c:\exec_dir"

How to load image files with webpack file-loader


    test: /\.(png|jpe?g|gif)$/i,
    loader: 'file-loader',
    options: {
        name: '[name].[ext]',


<img src={image_name.jpg} />

Static linking vs dynamic linking

There are a vast and increasing number of systems where an extreme level of static linking can have an enormous positive impact on applications and system performance.

I refer to what are often called "embedded systems", many of which are now increasingly using general-purpose operating systems, and these systems are used for everything imaginable.

An extremely common example are devices using GNU/Linux systems using Busybox. I've taken this to the extreme with NetBSD by building a bootable i386 (32-bit) system image that includes both a kernel and its root filesystem, the latter which contains a single static-linked (by crunchgen) binary with hard-links to all programs that itself contains all (well at last count 274) of the standard full-feature system programs (most except the toolchain), and it is less than 20 megabytes in size (and probably runs very comfortably in a system with only 64MB of memory (even with the root filesystem uncompressed and entirely in RAM), though I've been unable to find one so small to test it on).

It has been mentioned in earlier posts that the start-up time of a static-linked binaries is faster (and it can be a lot faster), but that is only part of the picture, especially when all object code is linked into the same file, and even more especially when the operating system supports demand paging of code direct from the executable file. In this ideal scenario the startup time of programs is literally negligible since almost all pages of code will already be in memory and be in use by the shell (and and init any other background processes that might be running), even if the requested program has not ever been run since boot since perhaps only one page of memory need be loaded to fulfill the runtime requirements of the program.

However that's still not the whole story. I also usually build and use the NetBSD operating system installs for my full development systems by static-linking all binaries. Even though this takes a tremendous amount more disk space (~6.6GB total for x86_64 with everything, including toolchain and X11 static-linked) (especially if one keeps full debug symbol tables available for all programs another ~2.5GB), the result still runs faster overall, and for some tasks even uses less memory than a typical dynamic-linked system that purports to share library code pages. Disk is cheap (even fast disk), and memory to cache frequently used disk files is also relatively cheap, but CPU cycles really are not, and paying the startup cost for every process that starts every time it starts will take hours and hours of CPU cycles away from tasks which require starting many processes, especially when the same programs are used over and over, such as compilers on a development system. Static-linked toolchain programs can reduce whole-OS multi-architecture build times for my systems by hours. I have yet to build the toolchain into my single crunchgen'ed binary, but I suspect when I do there will be more hours of build time saved because of the win for the CPU cache.

Downloading and unzipping a .zip file without writing to disk

Below is a code snippet I used to fetch zipped csv file, please have a look:

Python 2:

from StringIO import StringIO
from zipfile import ZipFile
from urllib import urlopen

resp = urlopen("")
zipfile = ZipFile(StringIO(
for line in
    print line

Python 3:

from io import BytesIO
from zipfile import ZipFile
from urllib.request import urlopen
# or: requests.get(url).content

resp = urlopen("")
zipfile = ZipFile(BytesIO(
for line in

Here file is a string. To get the actual string that you want to pass, you can use zipfile.namelist(). For instance,

resp = urlopen('')
zipfile = ZipFile(BytesIO(
# ['bbc.classes', '', 'bbc.mtx', 'bbc.terms']

Display UIViewController as Popup in iPhone

Modal Popups in Interface Builder (Storyboards)

Step 1

On the ViewController you want as your modal popup, make the background color of the root UIView clear. Set Clear Color on root view Tip: Do not use the root UIView as your popup. Add a new UIView that is smaller to be your popup.

Step 2

Create a Segue to the ViewController that has your popup. Select "Present Modally". Segue

Two Methods To Create Popup From Here

Method One - Using the Segue

Select the Segue and change Presentation to "Over Current Context": Over Current Context

Method Two - Using the View Controller

Select the ViewController Scene that is your popup. In Attributes Inspector, under View Controller section, set Presentation to "Over Current Context": ViewController

Either method will work. That should do it!

Finished Product

How to set ssh timeout?

Well, you could use nohup to run whatever you are running on 'non-blocking mode'. So you can just keep checking if whatever it was supposed to run, ran, otherwise exit.

nohup ./ &

echo "Script ended on Feb 15, 2011, 9:20AM" > /tmp/done.txt

So in the second one you just check if the file exists.

How to split and modify a string in NodeJS?

If you're using lodash and in the mood for a too-cute-for-its-own-good one-liner:'123, 124, 234,252'), _.add.bind(1, 1));

It's surprisingly robust thanks to lodash's powerful parsing capabilities.

If you want one that will also clean non-digit characters out of the string (and is easier to follow...and not quite so cutesy):

_.chain('123, 124, 234,252, n301')
   .replace(/[^\d,]/g, '')
   .map(_.partial(_.add, 1))

2017 edit:

I no longer recommend my previous solution. Besides being overkill and already easy to do without a third-party library, it makes use of _.chain, which has a variety of issues. Here's the solution I would now recommend:

const str = '123, 124, 234,252';
const arr = str.split(',').map(n => parseInt(n, 10) + 1);

My old answer is still correct, so I'll leave it for the record, but there's no need to use it nowadays.

Sending email with PHP from an SMTP server

In cases where you are hosting a Wordpress site on Linux and have server access you can save some headaches by installing msmtp which allows you to send via smtp from the standard php mail() function. msmtp is a simpler alternative to postfix which requires a bit more configuration.

Here are the steps:

Install msmtp

sudo apt-get install msmtp-mta ca-certificates

Create a new configuration file:

sudo nano /etc/msmtprc

...with the following configuration information:

# Set defaults.    

# Enable or disable TLS/SSL encryption.
tls on
tls_starttls on
tls_trust_file /etc/ssl/certs/ca-certificates.crt

# Set up a default account's settings.
account default
host <>
port 587
auth on
user <[email protected]>
password <password>
from <[email protected]>
syslog LOG_MAIL

You need to replace the configuration data represented by everything within "<" and ">" (inclusive, remove these). For host/username/password, use your normal credentials for sending mail through your mail provider.

Tell PHP to use it

sudo nano /etc/php5/apache2/php.ini

Add this single line:

sendmail_path = /usr/bin/msmtp -t

Complete documention can be found here:

How could others, on a local network, access my NodeJS app while it's running on my machine?

I had the same question and solved the problem. In my case, the Windows Firewall (not the router) was blocking the V8 machine I/O on the hosting machine.

  1. Go to windows button
  2. Search "Firewall"
  3. Choose "Allow programs to communicate through Firewall"
  4. Click Change Setup
  5. Tick all of "Evented I/O for V8 Javascript" OR "Node.js: Server-side Javascript"

My guess is that "Evented I/O for V8 Javascript" is the I/O process that node.js communicates to outside world and we need to free it before it can send packets outside of the local computer. After enabling this program to communicate over Windows firewall, I could use any port numbers to listen.

Resolve Javascript Promise outside function scope

I find myself missing the Deferred pattern as well in certain cases. You can always create one on top of a ES6 Promise:

export default class Deferred<T> {
    private _resolve: (value: T) => void = () => {};
    private _reject: (value: T) => void = () => {};

    private _promise: Promise<T> = new Promise<T>((resolve, reject) => {
        this._reject = reject;
        this._resolve = resolve;

    public get promise(): Promise<T> {
        return this._promise;

    public resolve(value: T) {

    public reject(value: T) {

Making a triangle shape using xml definitions?

You can use vector drawables.

If your minimum API is lower than 21, Android Studio automatically creates PNG bitmaps for those lower versions at build time (see Vector Asset Studio). If you use the support library, Android even manages "real vectors" down to API 7 (more on that in the update of this post at the bottom).

A red upwards pointing triangle would be:

<?xml version="1.0" encoding="utf-8"?>
<vector xmlns:android=""
    android:viewportWidth="100" >
            android:pathData="m 50,0 l 50,100 -100,0 z" />

Add it to your layout and remember to set clipChildren="false" if you rotate the triangle.

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



enter image description here

Change the size (width/height) of the triangle by setting the Views layout_width/layout_height attributes. This way you can also get an eqilateral triagle if you do the math correct.

UPDATE 25.11.2017

If you use the support library you can use real vectors (instead if bitmap creation) as far back as API 7. Simply add:

vectorDrawables.useSupportLibrary = true

do your defaultConfig in your module's build.gradle.

Then set the (vector xml) drawable like this:

    app:srcCompat="@drawable/triangle" />

Everything is documented very nicely on the Vector Asset Studio page.

Ever since this feature I've been working entirely without bitmaps in terms of icons. This also reduces APK size quite a bit.

How to Maximize a firefox browser window using Selenium WebDriver with node.js

As of 2020, the correct answer is :


How to enable named/bind/DNS full logging?

Run command rndc querylog on or add querylog yes; to options{}; section in named.conf to activate that channel.

Also make sure you’re checking correct directory if your bind is chrooted.

in querySelector: how to get the first and get the last elements? what traversal order is used in the dom?

Example to get last article or any other element:


Java - ignore exception and continue

LDAPService should contain method like LDAPService.isExists(String userName) use it to prevent NPE to be thrown. If is not - this could be a workaround, but use Logging to post some warning..

Why am I getting error CS0246: The type or namespace name could not be found?

  1. On the Solution Explorer tab right click and select Properties

  2. Resolve this issue by updating the Target Framework in the project application settings.

For instance, In my case the project was compiling with .net framework version 4.5.1 but the dll which were referenced were compiled with the version 4.6.1. So have updated the my project version. I hope it works for you.

enter image description here

Why an interface can not implement another interface?

However, interface is 100% abstract class and abstract class can implements interface(100% abstract class) without implement its methods. What is the problem when it is defining as "interface" ?

This is simply a matter of convention. The writers of the java language decided that "extends" is the best way to describe this relationship, so that's what we all use.

In general, even though an interface is "a 100% abstract class," we don't think about them that way. We usually think about interfaces as a promise to implement certain key methods rather than a class to derive from. And so we tend to use different language for interfaces than for classes.

As others state, there are good reasons for choosing "extends" over "implements."

How to get the url parameters using AngularJS

function GetURLParameter(parameter) {
        var url;
        var search;
        var parsed;
        var count;
        var loop;
        var searchPhrase;
        url = window.location.href;
        search = url.indexOf("?");
        if (search < 0) {
            return "";
        searchPhrase = parameter + "=";
        parsed = url.substr(search+1).split("&");
        count = parsed.length;
        for(loop=0;loop<count;loop++) {
            if (parsed[loop].substr(0,searchPhrase.length)==searchPhrase) {
                return decodeURI(parsed[loop].substr(searchPhrase.length));
        return "";

Set NA to 0 in R

You can just use the output of to replace directly with subsetting:[] <- 0

Or with a reproducible example:

dfr <- data.frame(x=c(1:3,NA),y=c(NA,4:6))
dfr[] <- 0
  x y
1 1 0
2 2 4
3 3 5
4 0 6

However, be careful using this method on a data frame containing factors that also have missing values:

> d <- data.frame(x = c(NA,2,3),y = c("a",NA,"c"))
> d[] <- 0
Warning message:
In `[<-.factor`(`*tmp*`, thisvar, value = 0) :
  invalid factor level, NA generated

It "works":

> d
  x    y
1 0    a
2 2 <NA>
3 3    c

...but you likely will want to specifically alter only the numeric columns in this case, rather than the whole data frame. See, eg, the answer below using dplyr::mutate_if.

wget can't download - 404 error

I had the same problem. Solved using single quotes like this:

$ wget ''

wget version in use:

$ wget --version
GNU Wget 1.11.4 Red Hat modified

Show week number with Javascript?

With that code you can simply;

document.write(dayNames[now.getDay()] + " (" + now.getWeek() + ").");

(You will need to paste the getWeek function above your current script)

How to loop and render elements in React.js without an array of objects to map?

Here is more functional example with some ES6 features:

'use strict';

const React = require('react');

function renderArticles(articles) {
    if (articles.length > 0) {      
        return, index) => (
            <Article key={index} article={article} />
    else return [];

const Article = ({article}) => {
    return ( 
        <article key={}>
            <a href={}>{article.title}</a>

const Articles = React.createClass({
    render() {
        const articles = renderArticles(this.props.articles);

        return (
                { articles }

module.exports = Articles;

How to find length of digits in an integer?

It's been several years since this question was asked, but I have compiled a benchmark of several methods to calculate the length of an integer.

def libc_size(i): 
    return libc.snprintf(buf, 100, c_char_p(b'%i'), i) # equivalent to `return snprintf(buf, 100, "%i", i);`

def str_size(i):
    return len(str(i)) # Length of `i` as a string

def math_size(i):
    return 1 + math.floor(math.log10(i)) # 1 + floor of log10 of i

def exp_size(i):
    return int("{:.5e}".format(i).split("e")[1]) + 1 # e.g. `1e10` -> `10` + 1 -> 11

def mod_size(i):
    return len("%i" % i) # Uses string modulo instead of str(i)

def fmt_size(i):
    return len("{0}".format(i)) # Same as above but str.format

(the libc function requires some setup, which I haven't included)

size_exp is thanks to Brian Preslopsky, size_str is thanks to GeekTantra, and size_math is thanks to John La Rooy

Here are the results:

Time for libc size:      1.2204 µs
Time for string size:    309.41 ns
Time for math size:      329.54 ns
Time for exp size:       1.4902 µs
Time for mod size:       249.36 ns
Time for fmt size:       336.63 ns
In order of speed (fastest first):
+ mod_size (1.000000x)
+ str_size (1.240835x)
+ math_size (1.321577x)
+ fmt_size (1.350007x)
+ libc_size (4.894290x)
+ exp_size (5.976219x)

(Disclaimer: the function is run on inputs 1 to 1,000,000)

Here are the results for sys.maxsize - 100000 to sys.maxsize:

Time for libc size:      1.4686 µs
Time for string size:    395.76 ns
Time for math size:      485.94 ns
Time for exp size:       1.6826 µs
Time for mod size:       364.25 ns
Time for fmt size:       453.06 ns
In order of speed (fastest first):
+ mod_size (1.000000x)
+ str_size (1.086498x)
+ fmt_size (1.243817x)
+ math_size (1.334066x)
+ libc_size (4.031780x)
+ exp_size (4.619188x)

As you can see, mod_size (len("%i" % i)) is the fastest, slightly faster than using str(i) and significantly faster than others.

How do I use hexadecimal color strings in Flutter?

Easy way :

String color = yourHexColor.replaceAll('#', '0xff');


    color: Color(int.parse(color)),

How to flush output of print function?

Dan's idea doesn't quite work:

#!/usr/bin/env python
class flushfile(file):
    def __init__(self, f):
        self.f = f
    def write(self, x):

import sys
sys.stdout = flushfile(sys.stdout)

print "foo"

The result:

Traceback (most recent call last):
  File "./", line 12, in <module>
    print "foo"
ValueError: I/O operation on closed file

I believe the problem is that it inherits from the file class, which actually isn't necessary. According to the docs for sys.stdout:

stdout and stderr needn’t be built-in file objects: any object is acceptable as long as it has a write() method that takes a string argument.

so changing

class flushfile(file):


class flushfile(object):

makes it work just fine.

DataGridView changing cell background color

try the following (in RowDataBound method of GridView):

protected void GridViewUsers_RowDataBound(object sender, GridViewRowEventArgs e)
    // this will only change the rows backgound not the column header 

    if (e.Row.RowType == DataControlRowType.DataRow)
        e.Row.Cells[0].BackColor = System.Drawing.Color.LightCyan; //first col
        e.Row.Cells[1].BackColor = System.Drawing.Color.Black; // second col

How to make this Header/Content/Footer layout using CSS?

Here is how to to that:

The header and footer are 30px height.

The footer is stuck to the bottom of the page.


<div id="header">
<div id="content">
<div id="footer">


#header {
    height: 30px;
#footer {
    height: 30px;
    position: absolute;
    bottom: 0;
body {
    height: 100%;
    margin-bottom: 30px;

Try it on jsfiddle:

Change value of variable with dplyr

We can use replace to change the values in 'mpg' to NA that corresponds to cyl==4.

mtcars %>%
     mutate(mpg=replace(mpg, cyl==4, NA)) %>%

How to use bluetooth to connect two iPhone?

You can connect two iPhones and transfer data via Bluetooth using either the high-level GameKit framework or the lower-level (but still easy to work with) Bonjour discovery mechanisms. Bonjour also works transparently between Bluetooth and WiFi on the iPhone under 3.0, so it's a good choice if you would like to support iPhone-to-iPhone data transfers on those two types of networks.

For more information, you can also look at the responses to these questions:

S3 - Access-Control-Allow-Origin Header

S3 now expects the rules to be in Array Json format.

You can find this in s3 bucket -> Permissions then -> scroll below -> () Cross-origin resource sharing (CORS)

        "AllowedHeaders": [
        "AllowedMethods": [
        "AllowedOrigins": [
        "ExposeHeaders": [],
        "MaxAgeSeconds": 3000

Getting attribute of element in ng-click function in angularjs

Addition to the answer of Brett DeWoody: (which is updated now)

var dataValue =;

Works fine in IE(9+) and Chrome, but Firefox does not know the srcElement property. I found:

var dataValue =;

Works in IE, Chrome and FF, I did not test Safari.

`export const` vs. `export default` in ES6

It's a named export vs a default export. export const is a named export that exports a const declaration or declarations.

To emphasize: what matters here is the export keyword as const is used to declare a const declaration or declarations. export may also be applied to other declarations such as class or function declarations.

Default Export (export default)

You can have one default export per file. When you import you have to specify a name and import like so:

import MyDefaultExport from "./MyFileWithADefaultExport";

You can give this any name you like.

Named Export (export)

With named exports, you can have multiple named exports per file. Then import the specific exports you want surrounded in braces:

// ex. importing multiple exports:
import { MyClass, MyOtherClass } from "./MyClass";
// ex. giving a named import a different name by using "as":
import { MyClass2 as MyClass2Alias } from "./MyClass2";

// use MyClass, MyOtherClass, and MyClass2Alias here

Or it's possible to use a default along with named imports in the same statement:

import MyDefaultExport, { MyClass, MyOtherClass} from "./MyClass";

Namespace Import

It's also possible to import everything from the file on an object:

import * as MyClasses from "./MyClass";
// use MyClasses.MyClass, MyClasses.MyOtherClass and MyClasses.default here


  • The syntax favours default exports as slightly more concise because their use case is more common (See the discussion here).
  • A default export is actually a named export with the name default so you are able to import it with a named import:

    import { default as MyDefaultExport } from "./MyFileWithADefaultExport";

How the int.TryParse actually works

Check this simple program to understand int.TryParse

 class Program
    static void Main()
        string str = "7788";
        int num1;
        bool n = int.TryParse(str, out num1);

Output is : 7788

How can I "reset" an Arduino board?

If the port says Already used, then you are probably using the wrong port.

Switch it to the port where you connected your Arduino and then try to re-upload, you will definitely see it work.

Android ADB devices unauthorized

Your app is being detected as some harmful program. Turn off "Verify apps over USB" option. It's in the same view as "USB debugging".

How should you diagnose the error SEHException - External component has thrown an exception

I had a similar problem with an SEHException that was thrown when my program first used a native dll wrapper. Turned out that the native DLL for that wrapper was missing. The exception was in no way helpful in solving this. What did help in the end was running procmon in the background and checking if there were any errors when loading all the necessary DLLs.

How to create a unique index on a NULL column?

Pretty sure you can't do that, as it violates the purpose of uniques.

However, this person seems to have a decent work around:

External resource not being loaded by AngularJs

Had the same issue here. I needed to bind to Youtube links. What worked for me, as a global solution, was to add the following to my config:

.config(['$routeProvider', '$sceDelegateProvider',
        function ($routeProvider, $sceDelegateProvider) {

    $sceDelegateProvider.resourceUrlWhitelist(['self', new RegExp('^(http[s]?):\/\/(w{3}.)?youtube\.com/.+$')]);


Adding 'self' in there is important - otherwise will fail to bind to any URL. From the angular docs

'self' - The special string, 'self', can be used to match against all URLs of the same domain as the application document using the same protocol.

With that in place, I'm now able to bind directly to any Youtube link.

You'll obviously have to customise the regex to your needs. Hope it helps!

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

you didn't give a value for id. Try this :

INSERT INTO role (id, name, created) VALUES ('example1','Content Coordinator', GETDATE()), ('example2', 'Content Viewer', GETDATE())

Or you can set the auto increment on id field, if you need the id value added automatically.

ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired

This error happens when the resource is busy. Check if you have any referential constraints in the query. Or even the tables that you have mentioned in the query may be busy. They might be engaged with some other job which will be definitely listed in the following query results:


Find the SID,


rejected master -> master (non-fast-forward)

i had created new repo in github and i had the same problem, but it also had problem while pulling, so this worked for me.

but this is not advised in repos that already have many codes as this could mess up everything

git push origin master --force

Neither user 10102 nor current process has android.permission.READ_PHONE_STATE

On Android >=6.0, We have to request permission runtime.

Step1: add in AndroidManifest.xml file

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

Step2: Request permission.

int permissionCheck = ContextCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE);

if (permissionCheck != PackageManager.PERMISSION_GRANTED) {
    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_PHONE_STATE}, REQUEST_READ_PHONE_STATE);
} else {

Step3: Handle callback when you request permission.

public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
    switch (requestCode) {
            if ((grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED)) {


Edit: Read official guide here Requesting Permissions at Run Time

Extracting a parameter from a URL in WordPress

When passing parameters through the URL you're able to retrieve the values as GET parameters.

Use this:

$variable = $_GET['param_name'];

//Or as you have it
$ppc = $_GET['ppc'];

It is safer to check for the variable first though:

if (isset($_GET['ppc'])) {
  $ppc = $_GET['ppc'];
} else {
  //Handle the case where there is no parameter

Here's a bit of reading on GET/POST params you should look at:

EDIT: I see this answer still gets a lot of traffic years after making it. Please read comments attached to this answer, especially input from @emc who details a WordPress function which accomplishes this goal securely.

How do I change the background color of the ActionBar of an ActionBarActivity using XML?

This worked for me, for AppCompatActivity,

    <item name="actionBarStyle">@style/BlackActionBar</item>

<style name="BlackActionBar" parent="@style/Widget.AppCompat.ActionBar.Solid">
    <item name="background">@android:color/black</item>
    <item name="titleTextStyle">@style/BlackActionBarTitleTextStyle</item>

<style name="BlackActionBarTitleTextStyle" parent="@style/TextAppearance.AppCompat.Widget.ActionBar.Title">
    <item name="android:textColor">@android:color/white</item>
    <item name="android:fontFamily">@font/cinzel_decorative</item>

How to create a directory and give permission in single command

Just to expand on and improve some of the above answers:

First, I'll check the mkdir man page for GNU Coreutils 8.26 -- it gives us this information about the option '-m' and '-p' (can also be given as --mode=MODE and --parents, respectively):

...set[s] file mode (as in chmod), not a=rwx - umask error if existing, make parent directories as needed

The statements are vague and unclear in my opinion. But basically, it says that you can make the directory with permissions specified by "chmod numeric notation" (octals) or you can go "the other way" and use a/your umask.

Side note: I say "the other way" since the umask value is actually exactly what it sounds like -- a mask, hiding/removing permissions rather than "granting" them as with chmod's numeric octal notation.

You can execute the shell-builtin command umask to see what your 3-digit umask is; for me, it's 022. This means that when I execute mkdir yodirectory in a given folder (say, mahome) and stat it, I'll get some output resembling this:

               755                   richard:richard         /mahome/yodirectory
 #          permissions                 user:group      what I just made (yodirectory),
 # (owner,group,others--in that order)                 where I made it (i.e. in mahome)

Now, to add just a tiny bit more about those octal permissions. When you make a directory, "your system" take your default directory perms' [which applies for new directories (its value should 777)] and slaps on yo(u)mask, effectively hiding some of those perms'. My umask is 022--now if we "subtract" 022 from 777 (technically subtracting is an oversimplification and not always correct - we are actually turning off perms or masking them)...we get 755 as stated (or "statted") earlier.

We can omit the '0' in front of the 3-digit octal (so they don't have to be 4 digits) since in our case we didn't want (or rather didn't mention) any sticky bits, setuids or setgids (you might want to look into those, btw, they might be useful since you are going 777). So in other words, 0777 implies (or is equivalent to) 777 (but 777 isn't necessarily equivalent to 0777--since 777 only specifies the permissions, not the setuids, setgids, etc.)

Now, to apply this to your question in a broader sense--you have (already) got a few options. All the answers above work (at least according to my coreutils). But you may (or are pretty likely to) run into problems with the above solutions when you want to create subdirectories (nested directories) with 777 permissions all at once. Specifically, if I do the following in mahome with a umask of 022:

mkdir -m 777 -p yodirectory/yostuff/mastuffinyostuff
# OR (you can swap 777 for 0777 if you so desire, outcome will be the same)
install -d -m 777 -p yodirectory/yostuff/mastuffinyostuff

I will get perms 755 for both yodirectory and yostuff, with only 777 perms for mastuffinyostuff. So it appears that the umask is all that's slapped on yodirectory and get around this we can use a subshell:

( umask 000 && mkdir -p yodirectory/yostuff/mastuffinyostuff )

and that's it. 777 perms for yostuff, mastuffinyostuff, and yodirectory.

Multi-dimensional arrays in Bash

If you want to use a bash script and keep it easy to read recommend putting the data in structured JSON, and then use lightweight tool jq in your bash command to iterate through the array. For example with the following dataset:





You can iterate through this data with a bash script and jq like this:

function loopOverArray(){

    jq -c '.[]' testing.json | while read i; do
        # Do stuff here
        echo "$i"




Python CSV error: line contains NULL byte

Instead of csv reader I use read file and split function for string:

lines = open(input_file,'rb') 

for line_all in lines:

    line=line_all.replace('\x00', '').split(";")

Django URLs TypeError: view must be a callable or a list/tuple in the case of include()

This error just means that myapp.views.home is not something that can be called, like a function. It is a string in fact. While your solution works in django 1.9, nevertheless it throws a warning saying this will deprecate from version 1.10 onwards, which is exactly what has happened. The previous solution by @Alasdair imports the necessary view functions into the script through either from myapp import views as myapp_views or from myapp.views import home, contact

Converting a char to uppercase

You can use Character#toUpperCase() for this.

char fUpper = Character.toUpperCase(f);
char lUpper = Character.toUpperCase(l);

It has however some limitations since the world is aware of many more characters than can ever fit in 16bit char range. See also the following excerpt of the javadoc:

Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the toUpperCase(int) method.

Kill a Process by Looking up the Port being used by it from a .BAT

Using Merlyn's solution caused other applications to be killed like firefox. These processes were using the same port, but not as a listener:


netstat -a -n -o | findstr :8085
  TCP               LISTENING       6568
  TCP         TIME_WAIT       0
  TCP         TIME_WAIT       0

Therefore, can excluded these by adding "LISTENING" to the findstr as follows:

FOR /F "tokens=5 delims= " %%P IN ('netstat -a -n -o ^| findstr :8085.*LISTENING') DO TaskKill.exe /PID %%P

Changing the width of Bootstrap popover

One tested solution for Bootstrap 4 beta:

.popover {
        min-width: 30em !important;

Together with the jQuery statement:

      container: 'body',
      trigger: 'focus',
      html: true,
      placement: 'top'

Side-note, data-container="body" or container: "body" in either HTML or as an option to the popover({}) object didn't really do the trick [maybe the do work but only together with the CSS statement];

Also, remember that Bootstrap 4 beta relies on popper.js for its popover and tooltip positioning (prior to that it was tether.js)

Spring Boot Java Config Set Session Timeout

You should be able to set the server.session.timeout in your file.


Input text dialog Android

Sounds like a good opportunity to use an AlertDialog.

As basic as it seems, Android does not have a built-in dialog to do this (as far as I know). Fortunately, it's just a little extra work on top of creating a standard AlertDialog. You simply need to create an EditText for the user to input data, and set it as the view of the AlertDialog. You can customize the type of input allowed using setInputType, if you need.

If you're able to use a member variable, you can simply set the variable to the value of the EditText, and it will persist after the dialog has dismissed. If you can't use a member variable, you may need to use a listener to send the string value to the right place. (I can edit and elaborate more if this is what you need).

Within your class:

private String m_Text = "";

Within the OnClickListener of your button (or in a function called from there):

AlertDialog.Builder builder = new AlertDialog.Builder(this);

// Set up the input
final EditText input = new EditText(this);
// Specify the type of input expected; this, for example, sets the input as a password, and will mask the text

// Set up the buttons
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() { 
    public void onClick(DialogInterface dialog, int which) {
        m_Text = input.getText().toString();
builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialog, int which) {

How do I set a Windows scheduled task to run in the background?

As noted by Mattias Nordqvist in the comments below, you can also select the radio button option "Run whether user is logged on or not". When saving the task, you will be prompted once for the user password. bambams noted that this wouldn't grant System permissions to the process, and also seems to hide the command window.

It's not an obvious solution, but to make a Scheduled Task run in the background, change the User running the task to "SYSTEM", and nothing will appear on your screen.

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Add marker to Google Map on Click

  1. First declare the marker:
this.marker = new google.maps.Marker({
   position: new google.maps.LatLng(12.924640523603115,77.61965398949724),
   map: map
  1. Call the method to plot the marker on click:
  1. Define the function:
placeMarker(location, map) {
    var marker = new google.maps.Marker({
        position: location,
        map: map

Sort array by firstname (alphabetically) in Javascript

I'm surprised no one mentioned Collators. You shouldn't use localeCompare unless you have to as it has significantly worse performance.

const collator = new Intl.Collator('zh-CN', { // Chinese Simplified for example
  numeric: true,
  sensitivity: 'base',

function sortAsc(a, b) {
  if (typeof a === 'string' && typeof b === 'string') {
    return, a)

  return b - a;

function sortDesc(a, b) {
  if (typeof a === 'string' && typeof b === 'string') {
    return, b);

  return a - b;

Write and read a list from file

If you don't need it to be human-readable/editable, the easiest solution is to just use pickle.

To write:

with open(the_filename, 'wb') as f:
    pickle.dump(my_list, f)

To read:

with open(the_filename, 'rb') as f:
    my_list = pickle.load(f)

If you do need them to be human-readable, we need more information.

If my_list is guaranteed to be a list of strings with no embedded newlines, just write them one per line:

with open(the_filename, 'w') as f:
    for s in my_list:
        f.write(s + '\n')

with open(the_filename, 'r') as f:
    my_list = [line.rstrip('\n') for line in f]

If they're Unicode strings rather than byte strings, you'll want to encode them. (Or, worse, if they're byte strings, but not necessarily in the same encoding as your system default.)

If they might have newlines, or non-printable characters, etc., you can use escaping or quoting. Python has a variety of different kinds of escaping built into the stdlib.

Let's use unicode-escape here to solve both of the above problems at once:

with open(the_filename, 'w') as f:
    for s in my_list:
        f.write((s + u'\n').encode('unicode-escape'))

with open(the_filename, 'r') as f:
    my_list = [line.decode('unicode-escape').rstrip(u'\n') for line in f]

You can also use the 3.x-style solution in 2.x, with either the codecs module or the io module:*

import io

with, 'w', encoding='unicode-escape') as f:
    f.writelines(line + u'\n' for line in my_list)

with open(the_filename, 'r') as f:
    my_list = [line.rstrip(u'\n') for line in f]

* TOOWTDI, so which is the one obvious way? It depends… For the short version: if you need to work with Python versions before 2.6, use codecs; if not, use io.

How to reset selected file with input tag file type in Angular 2?

Short version Plunker:

import { Component } from '@angular/core';

  selector: 'my-app',
  template: `
      <input #myInput type="file" placeholder="File Name" name="filename">
      <button (click)="myInput.value = ''">Reset</button>
export class AppComponent {


And i think more common case is to not using button but do reset automatically. Angular Template statements support chaining expressions so Plunker:

import { Component } from '@angular/core';

  selector: 'my-app',
  template: `
      <input #myInput type="file" (change)="onChange(myInput.value, $event); myInput.value = ''" placeholder="File Name" name="filename">
export class AppComponent {

  onChange(files, event) {
    alert( files );
    alert([0].name );


And interesting link about why there is no recursion on value change.

JSON to TypeScript class instance?

The best solution I found when dealing with Typescript classes and json objects: add a constructor in your Typescript class that takes the json data as parameter. In that constructor you extend your json object with jQuery, like this: $.extend( this, jsonData). $.extend allows keeping the javascript prototypes while adding the json object's properties.

export class Foo
    Name: string;
    getName(): string { return this.Name };

    constructor( jsonFoo: any )
        $.extend( this, jsonFoo);

In your ajax callback, translate your jsons in a your typescript object like this:

onNewFoo( jsonFoos : any[] )
  let receviedFoos = $.map( jsonFoos, (json) => { return new Foo( json ); } );

  // then call a method:
  let firstFooName = receviedFoos[0].GetName();

If you don't add the constructor, juste call in your ajax callback:

let newFoo = new Foo();
$.extend( newFoo, jsonData);
let name = newFoo.GetName()

...but the constructor will be useful if you want to convert the children json object too. See my detailed answer here.

Where can I find the error logs of nginx, using FastCGI and Django?

Type this command in the terminal:

sudo cat /var/log/nginx/error.log

What does "wrong number of arguments (1 for 0)" mean in Ruby?

You passed an argument to a function which didn't take any. For example:

def takes_no_arguments

takes_no_arguments 1
# ArgumentError: wrong number of arguments (1 for 0)

Combining "LIKE" and "IN" for SQL Server

No, you will have to use OR to combine your LIKE statements:

   column LIKE 'Text%' OR 
   column LIKE 'Link%' OR 
   column LIKE 'Hello%' OR
   column LIKE '%World%'

Have you looked at Full-Text Search?

SQL Server SELECT into existing table

SELECT ... INTO ... only works if the table specified in the INTO clause does not exist - otherwise, you have to use:

SELECT col1, col2
 WHERE col3 LIKE @search_key

This assumes there's only two columns in dbo.TABLETWO - you need to specify the columns otherwise:

  (col1, col2)
SELECT col1, col2
 WHERE col3 LIKE @search_key

Json.NET serialize object with root name

You can easily create your own serializer

var car = new Car() { Name = "Ford", Owner = "John Smith" };
string json = Serialize(car);

string Serialize<T>(T o)
    var attr = o.GetType().GetCustomAttribute(typeof(JsonObjectAttribute)) as JsonObjectAttribute;

    var jv = JValue.FromObject(o);

    return new JObject(new JProperty(attr.Title, jv)).ToString();

Oracle PL/SQL string compare issue

Let's fill in the gaps in your code, by adding the other branches in the logic, and see what happens:

  2   str1  varchar2(4000);
  3   str2  varchar2(4000);
  4  BEGIN
  5     str1:='';
  6     str2:='sdd';
  7     IF(str1<>str2) THEN
  8      dbms_output.put_line('The two strings is not equal');
  9     ELSIF (str1=str2) THEN
 10      dbms_output.put_line('The two strings are the same');
 11     ELSE
 12      dbms_output.put_line('Who knows?');
 13     END IF;
 14   END;
 15  /
Who knows?

PL/SQL procedure successfully completed.


So the two strings are neither the same nor are they not the same? Huh?

It comes down to this. Oracle treats an empty string as a NULL. If we attempt to compare a NULL and another string the outcome is not TRUE nor FALSE, it is NULL. This remains the case even if the other string is also a NULL.

Copy the entire contents of a directory in C#

My solution is basically a modification of @Termininja's answer, however I have enhanced it a bit and it appears to be more than 5 times faster than the accepted answer.

public static void CopyEntireDirectory(string path, string newPath)
    Parallel.ForEach(Directory.GetFileSystemEntries(path, "*", SearchOption.AllDirectories)
    ,(fileName) =>
        string output = Regex.Replace(fileName, "^" + Regex.Escape(path), newPath);
        if (File.Exists(fileName))
            File.Copy(fileName, output, true);

EDIT: Modifying @Ahmed Sabry to full parallel foreach does produce a better result, however the code uses recursive function and its not ideal in some situation.

public static void CopyEntireDirectory(DirectoryInfo source, DirectoryInfo target, bool overwiteFiles = true)
    if (!source.Exists) return;
    if (!target.Exists) target.Create();

    Parallel.ForEach(source.GetDirectories(), (sourceChildDirectory) =>
        CopyEntireDirectory(sourceChildDirectory, new DirectoryInfo(Path.Combine(target.FullName, sourceChildDirectory.Name))));

    Parallel.ForEach(source.GetFiles(), sourceFile =>
        sourceFile.CopyTo(Path.Combine(target.FullName, sourceFile.Name), overwiteFiles));

Ball to Ball Collision - Detection and Handling

You should use space partitioning to solve this problem.

Read up on Binary Space Partitioning and Quadtrees

EC2 Instance Cloning

Nowadays it is even easier to clone the machine with EBS-backed instances released a while ago. This is how we do it in BitNami Cloud Hosting. Basically you just take a snapshot of the instance which can be used later to launch a new server. You can do it either using AWS console (saving the EBS-backed instance as AWS AMI) or using the EC2 API tools:

Cloning the instance is nothing else but creating the backup and then launching a new server based on that. You can find bunch of articles out there describing this problem, try to find the info about "how to ..." backup or resize the whole EC2 instance, for example this blog is a really good place to start:

How do I replace a character in a string in Java?

StringBuilder s = new StringBuilder(token.length());

CharacterIterator it = new StringCharacterIterator(token);
for (char ch = it.first(); ch != CharacterIterator.DONE; ch = {
    switch (ch) {
        case '&':
        case '<':
        case '>':

token = s.toString();

How to prevent errno 32 broken pipe?

It depends on how you tested it, and possibly on differences in the TCP stack implementation of the personal computer and the server.

For example, if your sendall always completes immediately (or very quickly) on the personal computer, the connection may simply never have broken during sending. This is very likely if your browser is running on the same machine (since there is no real network latency).

In general, you just need to handle the case where a client disconnects before you're finished, by handling the exception.

Remember that TCP communications are asynchronous, but this is much more obvious on physically remote connections than on local ones, so conditions like this can be hard to reproduce on a local workstation. Specifically, loopback connections on a single machine are often almost synchronous.

How to modify a global variable within a function in bash?

Maybe you can use a file, write to file inside function, read from file after it. I have changed e to an array. In this example blanks are used as separator when reading back the array.


declare -a e

function test1 () {
 echo "${e[@]}" > /tmp/tempout
 echo hi


echo "$ret"

read -r -a e < /tmp/tempout
echo "${e[@]}"
echo "${e[0]}"
echo "${e[1]}"
echo "${e[2]}"


first second third

How to change menu item text dynamically in Android

you can do this create a global "Menu" object then assign it in onCreateOptionMenu

public class ExampleActivity extends AppCompatActivity
    Menu menu;

then assign here

public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(, menu); = menu;
    return true;

Then later use assigned Menu object to get required items

menu.findItem("Your Text");

Use Async/Await with Axios in React.js

In my experience over the past few months, I've realized that the best way to achieve this is:

class App extends React.Component{
   this.state = {
    serverResponse: ''
  async getData(){
   const res = await axios.get('url-to-get-the-data');
   const { data } = await res;
   this.setState({serverResponse: data})

If you are trying to make post request on events such as click, then call getData() function on the event and replace the content of it like so:

async getData(username, password){
 const res = await'url-to-post-the-data', {

Furthermore, if you are making any request when the component is about to load then simply replace async getData() with async componentDidMount() and change the render function like so:

 return (

newline character in c# string

A great way of handling this is with regular expressions.

string modifiedString = Regex.Replace(originalString, @"(\r\n)|\n|\r", "<br/>");

This will replace any of the 3 legal types of newline with the html tag.

How to Serialize a list in java?

List is just an interface. The question is: is your actual List implementation serializable? Speaking about the standard List implementations (ArrayList, LinkedList) from the Java run-time, most of them actually are already.

Is there a way to remove the separator line from a UITableView?

There is bug a iOS 9 beta 4: the separator line appears between UITableViewCells even if you set separatorStyle to UITableViewCellSeparatorStyleNone from the storyboard. To get around this, you have to set it from code, because as of now there is a bug from storyboard. Hope they will fix it in future beta.

Here's the code to set it:

[self.tableView setSeparatorStyle:UITableViewCellSeparatorStyleNone];

How to implement HorizontalScrollView like Gallery?

You may use HorizontalScrollView to implement Horizontal scrolling.


android:scrollbars="none" >
    android:orientation="horizontal" >


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




    android:text="Image Text" />


Java Code:

 LayoutInflater inflater;

    LinearLayout inLay=(LinearLayout) findViewById(;

    for(int x=0;x<10;x++)

 View getView(final int x)
   View rootView = inflater.inflate( R.layout.featured_item,null);

   ImageView image = (ImageView) rootView.findViewById(;

   //Thease Two Line is sufficient my dear to implement lazyLoading
   AQuery aq = new AQuery(rootView);
   String url="";, true, true, 0, R.drawable.placeholder1);
   image.setOnClickListener(new OnClickListener() {

        public void onClick(View arg0) {
     Toast.makeText(PhotoActivity.this, "Click Here Postion "+x,     

   return rootView;

Note: to implement lazy loading, please use this link for AQUERY

Regular expression for a string that does not start with a sequence

You could use a negative look-ahead assertion:


Or a negative look-behind assertion:


Or just plain old character sets and alternations:


What is difference between arm64 and armhf?

armhf stands for "arm hard float", and is the name given to a debian port for arm processors (armv7+) that have hardware floating point support.

On the beaglebone black, for example:

:~$ dpkg --print-architecture

Although other commands (such as uname -a or arch) will just show armv7l

:~$ cat /proc/cpuinfo 
processor       : 0
model name      : ARMv7 Processor rev 2 (v7l)
BogoMIPS        : 995.32
Features        : half thumb fastmult vfp edsp thumbee neon vfpv3 tls

The vfpv3 listed under Features is what refers to the floating point support.

Incidentally, armhf, if your processor supports it, basically supersedes Raspbian, which if I understand correctly was mainly a rebuild of armhf with work arounds to deal with the lack of floating point support on the original raspberry pi's. Nowdays, of course, there's a whole ecosystem build up around Raspbian, so they're probably not going to abandon it. However, this is partly why the beaglebone runs straight debian, and that's ok even if you're used to Raspbian, unless you want some of the special included non-free software such as Mathematica.

Object cannot be cast from DBNull to other types

I'm thinking that your output parameter is coming back with a DBNull value. Add a check for that like this

var outputParam = dataAccCom.GetParameterValue(IDbCmd, "op_Id");
if(!(outputParam is DBNull))
     DataTO.Id = Convert.ToInt64(outputParam);

xpath find if node exists

Might be better to use a choice, don't have to type (or possibly mistype) your expressions more than once, and allows you to follow additional different behaviors.

I very often use count(/html/body) = 0, as the specific number of nodes is more interesting than the set. For example... when there is unexpectedly more than 1 node that matches your expression.

    <xsl:when test="/html/body">
         <!-- Found the node(s) -->
    <!-- more xsl:when here, if needed -->
         <!-- No node exists -->

How to close off a Git Branch?

after complete the code first merge branch to master then delete that branch

git checkout master
git merge <branch-name>
git branch -d <branch-name>

Replace tabs with spaces in vim

If you want to keep your \t equal to 8 spaces then consider setting:

   set softtabstop=2 tabstop=8 shiftwidth=2

This will give you two spaces per <TAB> press, but actual \t in your code will still be viewed as 8 characters.

Jquery Button Click Event via ajax

In the client side handle the click event of the button, use the ClientID property to get he id of the button:

$(document).ready(function() {
$("#<%=myButton.ClientID %>,#<%=muSecondButton.ClientID%>").click(

    function() {
     $.get("/myPage.aspx",{id:$(this).attr('id')},function(data) {
       // do something with the data
     return false;

In your page on the server:

protected void Page_Load(object sender,EventArgs e) {
 // check if it is an ajax request
 if (Request.Headers["X-Requested-With"] == "XMLHttpRequest") {
  if (Request.QueryString["id"]==myButton.ClientID) {
    // call the click event handler of the myButton here
  if (Request.QueryString["id"]==mySecondButton.ClientID) {
    // call the click event handler of the mySecondButton here

How to select first parent DIV using jQuery?

Use .closest() to traverse up the DOM tree up to the specified selector.

var classes = $(this).parent().closest('div').attr('class').split(' '); // this gets the parent classes.

Bootstrap $('#myModal').modal('show') is not working

My root cause was that I forgot to add the # before the id name. Lame but true.





For your reference, the code sequence that works for me is

function scheduleRequest() {
<script src="<c:url value="/resources/bootstrap/js/bootstrap.min.js"/>">
    src="<c:url value="/resources/plugins/fastclick/fastclick.min.js"/>">
    src="<c:url value="/resources/plugins/slimScroll/jquery.slimscroll.min.js"/>">
    src="<c:url value="/resources/plugins/datatables/jquery.dataTables.min.js"/>">  
    src="<c:url value="/resources/plugins/datatables/dataTables.bootstrap.min.js"/>">
<script src="<c:url value="/resources/dist/js/demo.js"/>">

How to redirect 'print' output to a file using python?

If you are using Linux I suggest you to use the tee command. The implementation goes like this:

python | tee any_file_name.txt

If you don't want to change anything in the code, I think this might be the best possible solution. You can also implement logger but you need do some changes in the code.

How to reload/refresh an element(image) in jQuery

Have you tried resetting the image containers html. Of course if it's the browser that is caching then this wouldn't help.

function imageUploadComplete () {
    $("#image_container").html("<img src='" + newImageUrl + "'>");

Does Typescript support the ?. operator? (And, what's it called?)

It's finally here!

Here are a few examples:

// properties

// indexing

// check if a function is defined before invoking

But it doesn't work exactly the same as your assumption.

Instead of evaluating


to this little code snippet we are all used to writing

foo ? : null

it actually evaluates to

(foo === null || foo === undefined) ?
    undefined :

which works for all the falsey values like an empty string, 0 or false.

I just don't have an explanation as to why they don't compile it to foo == null

npm WARN package.json: No repository field

If you are getting this from your own package.json, just add the repository field to it. (use the link to your actual repository):

"repository" : { 
   "type" : "git",
   "url" : ""

How to do a non-greedy match in grep?

Sorry I am 9 years late, but this might work for the viewers in 2020.

So suppose you have a line like "Hello my name is Jello". Now you want to find the words that start with 'H' and end with 'o', with any number of characters in between. And we don't want lines we just want words. So for that we can use the expression:

grep "H[^ ]*o" file

This will return all the words. The way this works is that: It will allow all the characters instead of space character in between, this way we can avoid multiple words in the same line.

Now you can replace the space character with any other character you want. Suppose the initial line was "Hello-my-name-is-Jello", then you can get words using the expression:

grep "H[^-]*o" file

how to convert object into string in php

Use the casting operator (string)$yourObject;

Order data frame rows according to vector with specific order

Try match:

df <- data.frame(name=letters[1:4], value=c(rep(TRUE, 2), rep(FALSE, 2)))
target <- c("b", "c", "a", "d")
df[match(target, df$name),]

  name value
2    b  TRUE
3    c FALSE
1    a  TRUE
4    d FALSE

It will work as long as your target contains exactly the same elements as df$name, and neither contain duplicate values.

From ?match:

match returns a vector of the positions of (first) matches of its first argument 
in its second.

Therefore match finds the row numbers that matches target's elements, and then we return df in that order.

How to "select distinct" across multiple data frame columns in pandas?

I think use drop duplicate sometimes will not so useful depending dataframe.

I found this:

[in] df['col_1'].unique()
[out] array(['A', 'B', 'C'], dtype=object)

And work for me!

smooth scroll to top

Pure Javascript only

var t1 = 0;_x000D_
window.onscroll = scroll1;_x000D_
function scroll1() {_x000D_
  var toTop = document.getElementById('toTop');_x000D_
  window.scrollY > 0 ? = 'Block' : = 'none';_x000D_
function abcd() {_x000D_
  var y1 = window.scrollY;_x000D_
  y1 = y1 - 1000;_x000D_
  window.scrollTo(0, y1);_x000D_
  if (y1 > 0) {_x000D_
    t1 = setTimeout("abcd()", 100);_x000D_
  } else {_x000D_
#toTop {_x000D_
  display: block;_x000D_
  position: fixed;_x000D_
  bottom: 20px;_x000D_
  right: 20px;_x000D_
  font-size: 48px;_x000D_
#toTop {_x000D_
  transition: all 0.5s ease 0s;_x000D_
  -moz-transition: all 0.5s ease 0s;_x000D_
  -webkit-transition: all 0.5s ease 0s;_x000D_
  -o-transition: all 0.5s ease 0s;_x000D_
  opacity: 0.5;_x000D_
  display: none;_x000D_
  cursor: pointer;_x000D_
#toTop:hover {_x000D_
  opacity: 1;_x000D_
<p>your text here</p>_x000D_
<img id="toTop" src="" onclick="abcd()" title="Go To Top">

Get list of JSON objects with Spring RestTemplate

My big issue here was to build the Object structure required to match RestTemplate to a compatible Class. Luckily I found (get the JSON response in a browser and use it as input) and I can't recommend this enough!

IllegalArgumentException or NullPointerException for a null parameter?

Ideally runtime exceptions should not be thrown. A checked exception(business exception) should be created for your scenario. Because if either of these exception is thrown and logged, it misguides the developer while going through the logs. Instead business exceptions do not create that panic and usually ignored while troubleshooting logs.

Disable firefox same origin policy

The cors-everywhere addon works for me until Firefox 68, after 68 I need to adjust 'privacy.file_unique_origin' -> false (by open 'about:config') to solve 'CORS request not HTTP' for new CORS same-origin rule introduced.

There are no primary or candidate keys in the referenced table that match the referencing column list in the foreign key

BookTitle have a Composite key. so if the key of BookTitle is referenced as a foreign key you have to bring the complete composite key.

So to resolve the problem you need to add the complete composite key in the BookCopy. So add ISBN column as well. and they at the end.

foreign key (ISBN, Title) references BookTitle (ISBN, Title)

Convert String into a Class Object

You might want to do it with json.
Convert your bean(*) to json an then back.
this proccess is known as serialisation and deserialisation
read about it here

(*) Dont use just members as the data source, build getters and setters for each member in your object.

How to start and stop/pause setInterval?

You can't stop a timer function mid-execution. You can only catch it after it completes and prevent it from triggering again.

How to read data from a file in Lua

Try this:


-- see if the file exists
function file_exists(file)
  local f =, "rb")
  if f then f:close() end
  return f ~= nil

-- get all lines from a file, returns an empty 
-- list/table if the file does not exist
function lines_from(file)
  if not file_exists(file) then return {} end
  lines = {}
  for line in io.lines(file) do 
    lines[#lines + 1] = line
  return lines

-- tests the functions above
local file = 'test.lua'
local lines = lines_from(file)

-- print all line numbers and their contents
for k,v in pairs(lines) do
  print('line[' .. k .. ']', v)

Android: How to create a Dialog without a title?

In your code if you use requestWindowFeature(Window.FEATURE_NO_TITLE); be sure that it goes before dialog.setContentView(); otherwise it causes the application to crash.

Vim for Windows - What do I type to save and exit from a file?

:q! will force an unconditional no-save exit

jQuery click event not working in mobile browsers

You can use jQuery Mobile vclick event:

Normalized event for handling touchend or mouse click events on touch devices.

   $('.publications').vclick(function() {

Array definition in XML?

Once I've seen such an interesting construction:

<Ids xmlns:id="">

Formula to check if string is empty in Crystal Reports

if {le_gur_bond.gur1}="" or IsNull({le_gur_bond.gur1})   Then
 "and " + {le_gur_bond.gur2} + " of "+ {le_gur_bond.grr_2_address2}

Proper use of the IDisposable interface

Yep, that code is completely redundant and unnecessary and it doesn't make the garbage collector do anything it wouldn't otherwise do (once an instance of MyCollection goes out of scope, that is.) Especially the .Clear() calls.

Answer to your edit: Sort of. If I do this:

public void WasteMemory()
    var instance = new MyCollection(); // this one has no Dispose() method

// 1 million strings are in memory, but marked for reclamation by the GC

It's functionally identical to this for purposes of memory management:

public void WasteMemory()
    var instance = new MyCollection(); // this one has your Dispose()

// 1 million strings are in memory, but marked for reclamation by the GC

If you really really really need to free the memory this very instant, call GC.Collect(). There's no reason to do this here, though. The memory will be freed when it's needed.

How to convert nanoseconds to seconds using the TimeUnit enum?

Well, you could just divide by 1,000,000,000:

long elapsedTime = end - start;
double seconds = (double)elapsedTime / 1_000_000_000.0;

If you use TimeUnit to convert, you'll get your result as a long, so you'll lose decimal precision but maintain whole number precision.

Importing project into Netbeans

Try copying the src and web folder in different folder location and create New project with existing sources in Netbeans. This should work. Or remove the nbproject folder as well before importing.

Flutter: RenderBox was not laid out

Reason for the error:

Column tries to expands in vertical axis, and so does the ListView, hence you need to constrain the height of ListView.


  1. Use either Expanded or Flexible if you want to allow ListView to take up entire left space in Column.

      children: <Widget>[
          child: ListView(...),

  1. Use SizedBox if you want to restrict the size of ListView to a certain height.

      children: <Widget>[
          height: 200, // constrain height
          child: ListView(),

  1. Use shrinkWrap, if your ListView isn't too big.

      children: <Widget>[
          shrinkWrap: true, // use it

Solving Quadratic Equation

import math   
a = int(input("Enter the coefficients of a: "))
b = int(input("Enter the coefficients of b: "))
c = int(input("Enter the coefficients of c: "))

d = b**2-4*a*c # discriminant

if d < 0:
    print ("This equation has no real solution")
elif d == 0:
    x = (-b+math.sqrt(b**2-4*a*c))/2*a
    print (("This equation has one solutions: "), x)
#add the extra () above or it does not show the answer just the text.
    x1 = (-b+math.sqrt((b**2)-(4*(a*c))))/(2*a)
    x2 = (-b-math.sqrt((b**2)-(4*(a*c))))/(2*a)
    print ("This equation has two solutions: ", x1, " or", x2)

How do I specify C:\Program Files without a space in it for programs that can't handle spaces in file paths?

I think that the other posts have answered the question, but just some interesting for your information (from the command prompt):

dir c:\ /ad /x

This will provide a listing of only directories and also provide their "Short names".

How to force a hover state with jQuery?

Also, you could try triggering a mouseover.

$("#btn").click(function() {

Not sure if this will work for your specific scenario, but I've had success triggering mouseover instead of hover for various cases.

How to align the checkbox and label in same line in html?

You should use <label for=""> for the checkboxes or radios, and to align checkboxes vertical-align is enough

Try changing your markup to this

    <input id="checkid" type="checkbox" value="test" />
    <label for="checkid">testdata</label>

    <input id="checkid2" type="checkbox" value="test" />
    <label for="checkid2">testdata 2</label>

And set CSS like


In case of long text

    display: inline-block;
    vertical-align: middle;

Side note: In label, value of for must be the id of checkbox.


Updated Fiddle

The maximum message size quota for incoming messages (65536) has been exceeded

This worked for me:

 Dim binding As New WebHttpBinding(WebHttpSecurityMode.Transport)
 binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.None
 binding.MaxBufferSize = Integer.MaxValue
 binding.MaxReceivedMessageSize = Integer.MaxValue
 binding.MaxBufferPoolSize = Integer.MaxValue

When to use throws in a Java method declaration?

The code you posted is wrong, it should throw an Exception if is catching a specific exception in order to handler IOException but throwing not catched exceptions.

Something like:

public void method() throws Exception{
           BufferedReader br = new BufferedReader(new FileReader("file.txt"));
   }catch(IOException e){


public void method(){
           BufferedReader br = new BufferedReader(new FileReader("file.txt"));
   }catch(IOException e){
           System.out.println("Catching IOException");
   }catch(Exception e){
           System.out.println("Catching any other Exceptions like NullPontException, FileNotFoundExceptioon, etc.");


How to upload image in CodeIgniter?

check $this->upload->initialize($config); this works fine for me

    $new_image_name = "imgName".time() . str_replace(str_split(' ()\\/,:*?"<>|'), '', 
    $config = array();
    $config['upload_path'] = './uploads/'; 
    $config['allowed_types'] = 'gif|jpg|png|bmp|jpeg';
    $config['file_name'] = $new_image_name;
    $config['max_size']  = '0';
    $config['upload_path'] = './uploads/';
    $config['allowed_types'] = 'gif|jpg|png|mp4|jpeg';
    $config['file_name'] = url_title("imgsclogo");
    $config['max_size']      = '0';
    $config['overwrite']     = FALSE; 
    $data = $this->upload->data();

github changes not staged for commit

in my case, I needed a

 git add files
 git commit -am 'what I changed'
 git push

the 'a' on the commit was needed.

Apache error: _default_ virtualhost overlap on port 443

To resolve the issue on a Debian/Ubuntu system modify the /etc/apache2/ports.conf settings file by adding NameVirtualHost *:443 to it. My ports.conf is the following at the moment:

# /etc/apache/ports.conf
# If you just change the port or add more ports here, you will likely also
# have to change the VirtualHost statement in
# /etc/apache2/sites-enabled/000-default
# This is also true if you have upgraded from before 2.2.9-3 (i.e. from
# Debian etch). See /usr/share/doc/apache2.2-common/NEWS.Debian.gz and
# README.Debian.gz

NameVirtualHost *:80
Listen 80

<IfModule mod_ssl.c>
    # If you add NameVirtualHost *:443 here, you will also have to change
    # the VirtualHost statement in /etc/apache2/sites-available/default-ssl
    # to <VirtualHost *:443>
    # Server Name Indication for SSL named virtual hosts is currently not
    # supported by MSIE on Windows XP.

    NameVirtualHost *:443

    Listen 443

<IfModule mod_gnutls.c>
    NameVirtualHost *:443
    Listen 443

Furthermore ensure that 'sites-available/default-ssl' is not enabled, type a2dissite default-ssl to disable the site. While you're at it type a2dissite by itself to get a list and see if there is any other site settings that you have enabled that might be mapping onto port 443.

What is the difference between Eclipse for Java (EE) Developers and Eclipse Classic?

If you want to build Java EE applications, it's best to use Eclipse IDE for Java EE. It has editors from HTML to JSP/JSF, Javascript. It's rich for webapps development, and provide plugins and tools to develop Java EE applications easily (all bundled).

Eclipse Classic is basically the full featured Eclipse without the Java EE part.

What special characters must be escaped in regular expressions?

Unfortunately there really isn't a set set of escape codes since it varies based on the language you are using.

However, keeping a page like the Regular Expression Tools Page or this Regular Expression Cheatsheet can go a long way to help you quickly filter things out.

need to add a class to an element

Try using setAttribute on the result:


Objective-C ARC: strong vs retain and weak vs assign

After reading so many articles Stackoverflow posts and demo applications to check variable property attributes, I decided to put all the attributes information together:

  1. atomic //default
  2. nonatomic
  3. strong=retain //default
  4. weak
  5. retain
  6. assign //default
  7. unsafe_unretained
  8. copy
  9. readonly
  10. readwrite //default

Below is the detailed article link where you can find above mentioned all attributes, that will definitely help you. Many thanks to all the people who give best answers here!!

Variable property attributes or Modifiers in iOS

1.strong (iOS4 = retain )

  • it says "keep this in the heap until I don't point to it anymore"
  • in other words " I'am the owner, you cannot dealloc this before aim fine with that same as retain"
  • You use strong only if you need to retain the object.
  • By default all instance variables and local variables are strong pointers.
  • We generally use strong for UIViewControllers (UI item's parents)
  • strong is used with ARC and it basically helps you , by not having to worry about the retain count of an object. ARC automatically releases it for you when you are done with it.Using the keyword strong means that you own the object.


@property (strong, nonatomic) ViewController *viewController;

@synthesize viewController;

2.weak -

  • it says "keep this as long as someone else points to it strongly"
  • the same thing as assign, no retain or release
  • A "weak" reference is a reference that you do not retain.
  • We generally use weak for IBOutlets (UIViewController's Childs).This works because the child object only needs to exist as long as the parent object does.
  • a weak reference is a reference that does not protect the referenced object from collection by a garbage collector.
  • Weak is essentially assign, a unretained property. Except the when the object is deallocated the weak pointer is automatically set to nil

Example :

@property (weak, nonatomic) IBOutlet UIButton *myButton;

@synthesize myButton;

Strong & Weak Explanation, Thanks to BJ Homer:

Imagine our object is a dog, and that the dog wants to run away (be deallocated).

Strong pointers are like a leash on the dog. As long as you have the leash attached to the dog, the dog will not run away. If five people attach their leash to one dog, (five strong pointers to one object), then the dog will not run away until all five leashes are detached.

Weak pointers, on the other hand, are like little kids pointing at the dog and saying "Look! A dog!" As long as the dog is still on the leash, the little kids can still see the dog, and they'll still point to it. As soon as all the leashes are detached, though, the dog runs away no matter how many little kids are pointing to it.

As soon as the last strong pointer (leash) no longer points to an object, the object will be deallocated, and all weak pointers will be zeroed out.

When we use weak?

The only time you would want to use weak, is if you wanted to avoid retain cycles (e.g. the parent retains the child and the child retains the parent so neither is ever released).

3.retain = strong

  • it is retained, old value is released and it is assigned retain specifies the new value should be sent
  • retain on assignment and the old value sent -release
  • retain is the same as strong.
  • apple says if you write retain it will auto converted/work like strong only.
  • methods like "alloc" include an implicit "retain"


@property (nonatomic, retain) NSString *name;

@synthesize name;


  • assign is the default and simply performs a variable assignment
  • assign is a property attribute that tells the compiler how to synthesize the property's setter implementation
  • I would use assign for C primitive properties and weak for weak references to Objective-C objects.


@property (nonatomic, assign) NSString *address;

@synthesize address;

Twitter Bootstrap onclick event on buttons-radio

I see a lot of complicated answers, while this is super simple in Bootstrap 3:

Step 1: Use the official example code to create your radio button group, and give the container an id:

<div id="myButtons" class="btn-group" data-toggle="buttons">
  <label class="btn btn-primary active">
    <input type="radio" name="options" id="option1" autocomplete="off" checked> Radio 1 (preselected)
  <label class="btn btn-primary">
    <input type="radio" name="options" id="option2" autocomplete="off"> Radio 2
  <label class="btn btn-primary">
    <input type="radio" name="options" id="option3" autocomplete="off"> Radio 3

Step 2: Use this jQuery handler:

$("#myButtons :input").change(function() {
    console.log(this); // points to the clicked input button

Try the fiddle demo

Return multiple values to a method caller

Classes, Structures, Collections and Arrays can contain multiple values. Output and reference parameters can also be set in a function. Return multiple values is possible in dynamic and functional languages by means of tuples, but not in C#.

Nested iframes, AKA Iframe Inception

I guess your problem is that jQuery is not loaded in your iframes.

The safest approach is to rely on pure DOM-based methods to parse your content.

Or else, start with jQuery, and then once inside your iframes, test once if typeof window.jQuery == 'undefined', if it's true, jQuery is not enabled inside it and fallback on DOM-based method.