Programs & Examples On #Getfileversion

How to dispatch a Redux action with a timeout?

After trying the various popular approaches (action creators, thunks, sagas, epics, effects, custom middleware), I still felt that maybe there was room for improvement so I documented my journey in this blog article, Where do I put my business logic in a React/Redux application?

Much like the discussions here, I tried to contrast and compare the various approaches. Eventually it led me to introducing a new library redux-logic which takes inspiration from epics, sagas, custom middleware.

It allows you to intercept actions to validate, verify, authorize, as well as providing a way to perform async IO.

Some common functionality can simply be declared like debouncing, throttling, cancellation, and only using the response from the latest request (takeLatest). redux-logic wraps your code providing this functionality for you.

That frees you to implement your core business logic however you like. You don't have to use observables or generators unless you want to. Use functions and callbacks, promises, async functions (async/await), etc.

The code for doing a simple 5s notification would be something like:

const notificationHide = createLogic({_x000D_
  // the action type that will trigger this logic_x000D_
  // your business logic can be applied in several_x000D_
  // execution hooks: validate, transform, process_x000D_
  // We are defining our code in the process hook below_x000D_
  // so it runs after the action hit reducers, hide 5s later_x000D_
  process({ getState, action }, dispatch) {_x000D_
    setTimeout(() => {_x000D_
      dispatch({ type: 'NOTIFICATION_CLEAR' });_x000D_
    }, 5000);_x000D_

I have a more advanced notification example in my repo that works similar to what Sebastian Lorber described where you could limit the display to N items and rotate through any that queued up. redux-logic notification example

I have a variety of redux-logic jsfiddle live examples as well as full examples. I'm continuing to work on docs and examples.

I'd love to hear your feedback.

Escape single quote character for use in an SQLite query

for replace all (') in your string, use



sample = "St. Mary's and St. John's";
escapedSample = sample.replace(/\'/g,"''")

Regular expression for a hexadecimal number?

Another example: Hexadecimal values for css colors start with a pound sign, or hash (#), then six characters that can either be a numeral or a letter between A and F, inclusive.


Reset all changes after last commit in git

How can I undo every change made to my directory after the last commit, including deleting added files, resetting modified files, and adding back deleted files?

  1. You can undo changes to tracked files with:

    git reset HEAD --hard
  2. You can remove untracked files with:

    git clean -f
  3. You can remove untracked files and directories with:

    git clean -fd

    but you can't undo change to untracked files.

  4. You can remove ignored and untracked files and directories

    git clean -fdx

    but you can't undo change to ignored files.

You can also set clean.requireForce to false:

git config --global --add clean.requireForce false

to avoid using -f (--force) when you use git clean.

Java ArrayList Index

You have ArrayList all wrong,

  • You can't have an integer array and assign a string value.
  • You cannot do a add() method in an array

Rather do this:

List<String> alist = new ArrayList<String>();

String value = alist.get(1); //returns the 2nd item from list, in this case "banana"

Indexing is counted from 0 to N-1 where N is size() of list.

Error: Cannot find module html



instead of


What your trying to do is send a whole file.

This worked for me.


This isn't an answer. I just want to show that IF NOT EXISTS(...) INSERT method isn't safe. You have to execute first Session #1 and then Session #2. After v #2 you will see that without an UNIQUE index you could get duplicate pairs (SoftwareName,SoftwareSystemType). Delay from session #1 is used to give you enough time to execute the second script (session #2). You could reduce this delay.

Session #1 (SSMS > New Query > F5 (Execute))

CREATE TABLE dbo.Software(
    SoftwareName NCHAR(400) NOT NULL,  
    SoftwareSystemType NVARCHAR(50) NOT NULL

INSERT INTO dbo.Software(SoftwareID,SoftwareName,SoftwareSystemType)
VALUES (1,'Dynamics AX 2009','ERP');
INSERT INTO dbo.Software(SoftwareID,SoftwareName,SoftwareSystemType)
VALUES (2,'Dynamics NAV 2009','SCM');
INSERT INTO dbo.Software(SoftwareID,SoftwareName,SoftwareSystemType)
VALUES (3,'Dynamics CRM 2011','CRM');
INSERT INTO dbo.Software(SoftwareID,SoftwareName,SoftwareSystemType)
VALUES (4,'Dynamics CRM 2013','CRM');
INSERT INTO dbo.Software(SoftwareID,SoftwareName,SoftwareSystemType)
VALUES (5,'Dynamics CRM 2015','CRM');
CREATE UNIQUE INDEX IUN_Software_SoftwareName_SoftareSystemType
ON dbo.Software(SoftwareName,SoftwareSystemType);

-- Session #1
    UPDATE  dbo.Software
    SET     SoftwareName='Dynamics CRM',
    WHERE   SoftwareID=5;

    WAITFOR DELAY '00:00:15' -- 15 seconds delay; you have less than 15 seconds to switch SSMS window to session #2

    UPDATE  dbo.Software
    SET     SoftwareName='Dynamics AX',
    WHERE   SoftwareID=1;
PRINT 'Session #1 results:';
FROM dbo.Software;

Session #2 (SSMS > New Query > F5 (Execute))

-- Session #2
    @SoftwareName NVARCHAR(100),  
    @SoftwareSystemType NVARCHAR(50);
    @SoftwareName=N'Dynamics AX',

PRINT 'Session #2 results:';
    FROM dbo.Software s
    WHERE s.SoftwareName=@SoftwareName 
    AND s.SoftwareSystemType=@SoftwareSystemType)
    PRINT 'Session #2: INSERT';

    INSERT INTO dbo.Software(SoftwareID,SoftwareName,SoftwareSystemType)
    VALUES (6,@SoftwareName,@SoftwareSystemType);
PRINT 'Session #2: FINISH';
FROM    dbo.Software;


Session #1 results:
SoftwareID  SoftwareName      SoftwareSystemType
----------- ----------------- ------------------
1           Dynamics AX       ERP
2           Dynamics NAV 2009 SCM
3           Dynamics CRM 2011 CRM
4           Dynamics CRM 2013 CRM
5           Dynamics CRM      CRM

Session #2 results:
Session #2: INSERT
Session #2: FINISH
SoftwareID  SoftwareName      SoftwareSystemType
----------- ----------------- ------------------
1           Dynamics AX       ERP <-- duplicate (row updated by session #1)
2           Dynamics NAV 2009 SCM
3           Dynamics CRM 2011 CRM
4           Dynamics CRM 2013 CRM
5           Dynamics CRM      CRM
6           Dynamics AX       ERP <-- duplicate (row inserted by session #2)

How to use onResume()?

The best way to understand would be to have all the LifeCycle methods overridden in your activity and placing a breakpoint(if checking in emulator) or a Log in each one of them. You'll get to know which one gets called when.

Just as an spoiler, onCreate() gets called first, then if you paused the activity by either going to home screen or by launching another activity, onPause() gets called. If the OS destroys the activity in the meantime, onDestroy() gets called. If you resume the app and the app already got destroyed, onCreate() will get called, or else onResume() will get called.

Edit: I forgot about onStop(), it gets called before onDestroy().

Do the exercise I mentioned and you'll be having a better understanding.

SQLite: How do I save the result of a query as a CSV file?

From here and d5e5's comment:

You'll have to switch the output to csv-mode and switch to file output.

sqlite> .mode csv
sqlite> .output test.csv
sqlite> select * from tbl1;
sqlite> .output stdout

How do you create a yes/no boolean field in SQL server?

The BIT datatype is generally used to store boolean values (0 for false, 1 for true).

How to analyze information from a Java core dump?

I recommend you to try Netbeans Profiler.It has rich set of tools for real time analysis. Tools from IbM are worth a try for offline analysis

Strip HTML from Text JavaScript

Using Jquery:

function stripTags() {
    return $('<p></p>').html(textToEscape).text()

linq where list contains any in list

You can use a Contains query for this:

var movies = _db.Movies.Where(p => p.Genres.Any(x => listOfGenres.Contains(x));

Best HTTP Authorization header type for JWT

Short answer

The Bearer authentication scheme is what you are looking for.

Long answer

Is it related to bears?

Errr... No :)

According to the Oxford Dictionaries, here's the definition of bearer:

bearer /'b??r?/

  1. A person or thing that carries or holds something.

  2. A person who presents a cheque or other order to pay money.

The first definition includes the following synonyms: messenger, agent, conveyor, emissary, carrier, provider.

And here's the definition of bearer token according to the RFC 6750:

1.2. Terminology

Bearer Token

A security token with the property that any party in possession of the token (a "bearer") can use the token in any way that any other party in possession of it can. Using a bearer token does not require a bearer to prove possession of cryptographic key material (proof-of-possession).

The Bearer authentication scheme is registered in IANA and originally defined in the RFC 6750 for the OAuth 2.0 authorization framework, but nothing stops you from using the Bearer scheme for access tokens in applications that don't use OAuth 2.0.

Stick to the standards as much as you can and don't create your own authentication schemes.

An access token must be sent in the Authorization request header using the Bearer authentication scheme:

2.1. Authorization Request Header Field

When sending the access token in the Authorization request header field defined by HTTP/1.1, the client uses the Bearer authentication scheme to transmit the access token.

For example:

GET /resource HTTP/1.1
Authorization: Bearer mF_9.B5f-4.1JqM


Clients SHOULD make authenticated requests with a bearer token using the Authorization request header field with the Bearer HTTP authorization scheme. [...]

In case of invalid or missing token, the Bearer scheme should be included in the WWW-Authenticate response header:

3. The WWW-Authenticate Response Header Field

If the protected resource request does not include authentication credentials or does not contain an access token that enables access to the protected resource, the resource server MUST include the HTTP WWW-Authenticate response header field [...].

All challenges defined by this specification MUST use the auth-scheme value Bearer. This scheme MUST be followed by one or more auth-param values. [...].

For example, in response to a protected resource request without authentication:

HTTP/1.1 401 Unauthorized
WWW-Authenticate: Bearer realm="example"

And in response to a protected resource request with an authentication attempt using an expired access token:

HTTP/1.1 401 Unauthorized
WWW-Authenticate: Bearer realm="example",
                         error_description="The access token expired"

Write to .txt file?

Well, you need to first get a good book on C and understand the language.

FILE *fp;
fp = fopen("c:\\test.txt", "wb");
if(fp == null)
char x[10]="ABCDEFGHIJ";
fwrite(x, sizeof(x[0]), sizeof(x)/sizeof(x[0]), fp);

VBA Object doesn't support this property or method

Object doesn't support this property or method.

Think of it like if anything after the dot is called on an object. It's like a chain.

An object is a class instance. A class instance supports some properties defined in that class type definition. It exposes whatever intelli-sense in VBE tells you (there are some hidden members but it's not related to this). So after each dot . you get intelli-sense (that white dropdown) trying to help you pick the correct action.

(you can start either way - front to back or back to front, once you understand how this works you'll be able to identify where the problem occurs)

Type this much anywhere in your code area

Dim a As Worksheets

you get help from VBE, it's a little dropdown called Intelli-sense

enter image description here

It lists all available actions that particular object exposes to any user. You can't see the .Selection member of the Worksheets() class. That's what the error tells you exactly.

Object doesn't support this property or method.

If you look at the example on MSDN

iAreaCount = Selection.Areas.Count

It activates the sheet first then calls the Selection... it's not connected together because Selection is not a member of Worksheets() class. Simply, you can't prefix the Selection

What about

Sub DisplayColumnCount()
    Dim iAreaCount As Integer
    Dim i As Integer

    iAreaCount = Selection.Areas.Count

    If iAreaCount <= 1 Then
        MsgBox "The selection contains " & Selection.Columns.Count & " columns."
        For i = 1 To iAreaCount
        MsgBox "Area " & i & " of the selection contains " & _
        Selection.Areas(i).Columns.Count & " columns."
        Next i
    End If
End Sub

from HERE

Ruby on Rails: how to render a string as HTML?

Or you can try CGI.unescapeHTML method.

CGI.unescapeHTML "&lt;p&gt;This is a Paragraph.&lt;/p&gt;"
=> "<p>This is a Paragraph.</p>"

AJAX post error : Refused to set unsafe header "Connection"

Remove these two lines:

xmlHttp.setRequestHeader("Content-length", params.length);
xmlHttp.setRequestHeader("Connection", "close");

XMLHttpRequest isn't allowed to set these headers, they are being set automatically by the browser. The reason is that by manipulating these headers you might be able to trick the server into accepting a second request through the same connection, one that wouldn't go through the usual security checks - that would be a security vulnerability in the browser.

How to get the <td> in HTML tables to fit content, and let a specific <td> fill in the rest

Setting CSS width to 1% or 100% of an element according to all specs I could find out is related to the parent. Although Blink Rendering Engine (Chrome) and Gecko (Firefox) at the moment of writing seems to handle that 1% or 100% (make a columns shrink or a column to fill available space) well, it is not guaranteed according to all CSS specifications I could find to render it properly.

One option is to replace table with CSS4 flex divs:

That works in new browsers i.e. IE11+ see table at the bottom of the article.

how do you increase the height of an html textbox

Use CSS:

    font-size: 16pt;
    height: 50px;
<input type="text" class="Large">

How can I change image source on click with jQuery?

It switches back because by default, when you click a link, it follows the link and loads the page. In your case, you don't want that. You can prevent it either by doing e.preventDefault(); (like Neal mentioned) or by returning false :

$(function() {
   return false;

Interesting question on the differences between prevent default and return false.

In this case, return false will work just fine because the event doesn't need to be propagated.

How to escape single quotes within single quoted strings

Both versions are working, either with concatenation by using the escaped single quote character (\'), or with concatenation by enclosing the single quote character within double quotes ("'").

The author of the question did not notice that there was an extra single quote (') at the end of his last escaping attempt:

alias rxvt='urxvt -fg'\''#111111'\'' -bg '\''#111111'\''
           ¦         ¦??|       ¦??¦     ¦??¦       ¦??¦
                      ??         ??       ??         ??¦
                      ??         ??       ??         ??¦
                          All escaped single quotes    ¦

As you can see in the previous nice piece of ASCII/Unicode art, the last escaped single quote (\') is followed by an unnecessary single quote ('). Using a syntax-highlighter like the one present in Notepad++ can prove very helpful.

The same is true for another example like the following one:

alias rc='sed '"'"':a;N;$!ba;s/\n/, /g'"'"
alias rc='sed '\'':a;N;$!ba;s/\n/, /g'\'

These two beautiful instances of aliases show in a very intricate and obfuscated way how a file can be lined down. That is, from a file with a lot of lines you get only one line with commas and spaces between the contents of the previous lines. In order to make sense of the previous comment, the following is an example:

$ cat Little_Commas.TXT

$ rc Little_Commas.TXT
201737194, 201802699, 201835214

Calling a JSON API with Node.js

I'm using get-json very simple to use:

$ npm install get-json --save

Import get-json

var getJSON = require('get-json')

To do a GET request you would do something like:

getJSON('', function(error, response){

How to automatically generate getters and setters in Android Studio

As noted here, you can also customise the getter/setter generation to take prefixes and suffixes (e.g. m for instance variables) into account. Go to File->Settings and expand Code Style, select Java, and add your prefixes/suffixes under the Code Generation tab.

Convert string to ASCII value python

Here is a pretty concise way to perform the concatenation:

>>> s = "hello world"
>>> ''.join(str(ord(c)) for c in s)

And a sort of fun alternative:

>>> '%d'*len(s) % tuple(map(ord, s))

Excel- compare two cell from different sheet, if true copy value from other cell

In your destination field you want to use VLOOKUP like so:


VLOOKUP Arguments:

  1. The set fields you want to lookup.
  2. The table range you want to lookup up your value against. The first column of your defined table should be the column you want compared against your lookup field. The table range should also contain the value you want to display (Column F).
  3. This defines what field you want to display upon a match.
  4. FALSE tells VLOOKUP to do an exact match.

How to cin to a vector

using namespace std;
int main()
    int num;
    string input;
    while (cin>>input && num != 0) //enter any non-integer to end the loop!
   vector<string>::iterator it;

return 0;


How to stop asynctask thread in android?

You can't just kill asynctask immediately. In order it to stop you should first cancel it:


and than in asynctask's doInBackground() method check if it's already cancelled:


and if it is, stop executing it manually.

Can you target an elements parent element using

To use the parent of an element use parentElement:

function selectedProduct(event){
  var target =;
  var parent = target.parentElement;//parent of "target"

Angular 2 change event - model changes

That's a known issue. Currently you have to use a workaround like shown in your question.

This is working as intended. When the change event is emitted ngModelChange (the (...) part of [(ngModel)] hasn't updated the bound model yet:

<input type="checkbox"  (ngModelChange)="myModel=$event" [ngModel]="mymodel">

See also

How can I change the version of npm using nvm?

What about npm i -g npm? Did you try to run this as well?

What are NDF Files?

An NDF file is a user defined secondary database file of Microsoft SQL Server with an extension .ndf, which store user data. Moreover, when the size of the database file growing automatically from its specified size, you can use .ndf file for extra storage and the .ndf file could be stored on a separate disk drive. Every NDF file uses the same filename as its corresponding MDF file. We cannot open an .ndf file in SQL Server Without attaching its associated .mdf file.

Full-screen iframe with a height of 100%

This is a great resource and has worked very well, the few times I've used it. Creates the following code....

.embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } 
.embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }
<div class='embed-container'>
<iframe src='' frameborder='0' webkitAllowFullScreen mozallowfullscreen allowFullScreen></iframe>

List of all special characters that need to be escaped in a regex

You can look at the javadoc of the Pattern class:

You need to escape any char listed there if you want the regular char and not the special meaning.

As a maybe simpler solution, you can put the template between \Q and \E - everything between them is considered as escaped.

How do I detect what .NET Framework versions and service packs are installed?

Enumerate the subkeys of HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP. Each subkey is a .NET version. It should have Install=1 value if it's present on the machine, an SP value that shows the service pack and an MSI=1 value if it was installed using an MSI. (.NET 2.0 on Windows Vista doesn't have the last one for example, as it is part of the OS.)

How to remove spaces from a string using JavaScript?

Following @rsplak answer: actually, using split/join way is faster than using regexp. See the performance test case


var result = text.split(' ').join('')

operates faster than

var result = text.replace(/\s+/g, '')

On small texts this is not relevant, but for cases when time is important, e.g. in text analisers, especially when interacting with users, that is important.

On the other hand, \s+ handles wider variety of space characters. Among with \n and \t, it also matches \u00a0 character, and that is what &nbsp; is turned in, when getting text using textDomNode.nodeValue.

So I think that conclusion in here can be made as follows: if you only need to replace spaces ' ', use split/join. If there can be different symbols of symbol class - use replace(/\s+/g, '')

What's the best way to generate a UML diagram from Python source code?

Sparx's Enterprise Architect performs round-tripping of Python source. They have a free time-limited trial edition.

How do I clear a C++ array?

Should you want to clear the array with something other than a value, std::file wont cut it; instead I found std::generate useful. e.g. I had a vector of lists I wanted to initialize

std::generate(v.begin(), v.end(), [] () { return std::list<X>(); });

You can do ints too e.g.

std::generate(v.begin(), v.end(), [n = 0] () mutable { return n++; });

or just

std::generate(v.begin(), v.end(), [] (){ return 0; });

but I imagine std::fill is faster for the simplest case

Is it bad to have my virtualenv directory inside my git repository?

If you just setting up development env, then use pip freeze file, caz that makes the git repo clean.

Then if doing production deployment, then checkin the whole venv folder. That will make your deployment more reproducible, not need those libxxx-dev packages, and avoid the internet issues.

So there are two repos. One for your main source code, which includes a requirements.txt. And a env repo, which contains the whole venv folder.

Sort Go map values by keys

If, like me, you find you want essentially the same sorting code in more than one place, or just want to keep the code complexity down, you can abstract away the sorting itself to a separate function, to which you pass the function that does the actual work you want (which would be different at each call site, of course).

Given a map with key type K and value type V, represented as <K> and <V> below, the common sort function might look something like this Go-code template (which Go version 1 does not support as-is):

/* Go apparently doesn't support/allow 'interface{}' as the value (or
/* key) of a map such that any arbitrary type can be substituted at
/* run time, so several of these nearly-identical functions might be
/* needed for different key/value type combinations. */
func sortedMap<K><T>(m map[<K>]<V>, f func(k <K>, v <V>)) {
    var keys []<K>
    for k, _ := range m {
        keys = append(keys, k)
    sort.Strings(keys)  # or sort.Ints(keys), sort.Sort(...), etc., per <K>
    for _, k := range keys {
        v := m[k]
        f(k, v)

Then call it with the input map and a function (taking (k <K>, v <V>) as its input arguments) that is called over the map elements in sorted-key order.

So, a version of the code in the answer posted by Mingu might look like:

package main

import (

func sortedMapIntString(m map[int]string, f func(k int, v string)) {
    var keys []int
    for k, _ := range m {
        keys = append(keys, k)
    for _, k := range keys {
        f(k, m[k])

func main() {
    // Create a map for processing
    m := make(map[int]string)
    m[1] = "a"
    m[2] = "c"
    m[0] = "b"

        func(k int, v string) { fmt.Println("Key:", k, "Value:", v) })

The sortedMapIntString() function can be re-used for any map[int]string (assuming the same sort order is desired), keeping each use to just two lines of code.

Downsides include:

  • It's harder to read for people unaccustomed to using functions as first-class
  • It might be slower (I haven't done performance comparisons)

Other languages have various solutions:

  • If the use of <K> and <V> (to denote types for the key and value) looks a bit familiar, that code template is not terribly unlike C++ templates.
  • Clojure and other languages support sorted maps as fundamental data types.
  • While I don't know of any way Go makes range a first-class type such that it could be substituted with a custom ordered-range (in place of range in the original code), I think some other languages provide iterators that are powerful enough to accomplish the same thing.

How to turn a vector into a matrix in R?

A matrix is really just a vector with a dim attribute (for the dimensions). So you can add dimensions to vec using the dim() function and vec will then be a matrix:

vec <- 1:49
dim(vec) <- c(7, 7)  ## (rows, cols)

> vec <- 1:49
> dim(vec) <- c(7, 7)  ## (rows, cols)
> vec
     [,1] [,2] [,3] [,4] [,5] [,6] [,7]
[1,]    1    8   15   22   29   36   43
[2,]    2    9   16   23   30   37   44
[3,]    3   10   17   24   31   38   45
[4,]    4   11   18   25   32   39   46
[5,]    5   12   19   26   33   40   47
[6,]    6   13   20   27   34   41   48
[7,]    7   14   21   28   35   42   49

.NET / C# - Convert char[] to string

char[] chars = {'a', ' ', 's', 't', 'r', 'i', 'n', 'g'};
string s = new string(chars);

GUI Tool for PostgreSQL

Postgres Enterprise Manager from EnterpriseDB is probably the most advanced you'll find. It includes all the features of pgAdmin, plus monitoring of your hosts and database servers, predictive reporting, alerting and a SQL Profiler.

Ninja edit disclaimer/notice: it seems that this user is affiliated with EnterpriseDB, as the linked Postgres Enterprise Manager website contains a video of one Dave Page.

Is there a way to make mv create the directory to be moved to if it doesn't exist?

Based on a comment in another answer, here's my shell function.

# mvp = move + create parents
function mvp () {
    target_dir="$(dirname "$target")"
    mkdir --parents $target_dir; mv $source $target

Include this in .bashrc or similar so you can use it everywhere.

Getting Data from Android Play Store

The Google Play Store doesn't provide this data, so the sites must just be scraping it.

ASP.NET MVC passing an ID in an ActionLink to the controller

In MVC 4 you can link from one view to another controller passing the Id or Primary Key via

@Html.ActionLink("Select", "Create", "StudentApplication", new { id=item.PersonId }, null) 

Delete all duplicate rows Excel vba

The duplicate values in any column can be deleted with a simple for loop.

Sub remove()
Dim a As Long
For a = Cells(Rows.Count, 1).End(xlUp).Row To 1 Step -1
If WorksheetFunction.CountIf(Range("A1:A" & a), Cells(a, 1)) > 1 Then Rows(a).Delete
End Sub

Allow only numbers to be typed in a textbox

With HTML5 you can do

<input type="number">

You can also use a regex pattern to limit the input text.

<input type="text" pattern="^[0-9]*$" />

Java: random long number in 0 <= x < n range

How about this:

public static long nextLong(@NonNull Random r, long min, long max) {
    if (min > max)
        throw new IllegalArgumentException("min>max");
    if (min == max)
        return min;
    long n = r.nextLong();
    //abs (use instead of Math.abs, which might return min value) :
    n = n == Long.MIN_VALUE ? 0 : n < 0 ? -n : n;
    //limit to range:
    n = n % (max - min);
    return min + n;


Cannot deserialize the JSON array (e.g. [1,2,3]) into type ' ' because type requires JSON object (e.g. {"name":"value"}) to deserialize correctly

If one wants to support Generics (in an extension method) this is the pattern...

public  static List<T> Deserialize<T>(this string SerializedJSONString)
    var stuff = JsonConvert.DeserializeObject<List<T>>(SerializedJSONString);
    return stuff;

It is used like this:

var rc = new MyHttpClient(URL);
//This response is the JSON Array (see posts above)
var response = rc.SendRequest();
var data = response.Deserialize<MyClassType>();

MyClassType looks like this (must match name value pairs of JSON array)

[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
 public class MyClassType
    [JsonProperty(PropertyName = "Id")]
    public string Id { get; set; }

    [JsonProperty(PropertyName = "Name")]
    public string Name { get; set; }

    [JsonProperty(PropertyName = "Description")]
    public string Description { get; set; }

    [JsonProperty(PropertyName = "Manager")]
    public string Manager { get; set; }

    [JsonProperty(PropertyName = "LastUpdate")]
    public DateTime LastUpdate { get; set; }

Use NUGET to download Newtonsoft.Json add a reference where needed...

using Newtonsoft.Json;

Sorting arrays in javascript by object key value

Here is yet another one-liner for you:

your_array.sort((a, b) => a.distance === b.distance ? 0 : a.distance > b.distance || -1);

Installing MySQL-python

On Ubuntu it is advised to use the distributions repository. So installing python-mysqldb should be straight forward:

sudo apt-get install python-mysqldb

If you actually want to use pip to install, which is as mentioned before not the suggested path but possible, please have a look at this previously asked question and answer: pip install mysql-python fails with EnvironmentError: mysql_config not found

Here is a very comprehensive guide by the developer:

To get all the prerequisites for python-mysqld to install it using pip (which you will want to do if you are using virtualenv), run this:

sudo apt-get install build-essential python-dev libmysqlclient-dev

Changing the space between each item in Bootstrap navbar

As of Bootstrap 4, you can use the spacing utilities.

Add for instance px-2 in the classes of the nav-item to increase the padding.

How do I write to a Python subprocess' stdin?

It might be better to use communicate:

from subprocess import Popen, PIPE, STDOUT
p = Popen(['myapp'], stdout=PIPE, stdin=PIPE, stderr=PIPE)
stdout_data = p.communicate(input='data_to_write')[0]

"Better", because of this warning:

Use communicate() rather than .stdin.write, or to avoid deadlocks due to any of the other OS pipe buffers filling up and blocking the child process.

Adding items to a JComboBox

addItem(Object) takes an object. The default JComboBox renderer calls toString() on that object and that's what it shows as the label.

So, don't pass in a String to addItem(). Pass in an object whose toString() method returns the label you want. The object can contain any number of other data fields also.

Try passing this into your combobox and see how it renders. getSelectedItem() will return the object, which you can cast back to Widget to get the value from.

public final class Widget {
    private final int value;
    private final String label;

    public Widget(int value, String label) {
        this.value = value;
        this.label = label;

    public int getValue() {
        return this.value;

    public String toString() {
        return this.label;

finding the type of an element using jQuery

It is worth noting that @Marius's second answer could be used as pure Javascript solution.


Compiling dynamic HTML strings from database

Try this below code for binding html through attr

.directive('dynamic', function ($compile) {
    return {
      restrict: 'A',
      replace: true,
      scope: { dynamic: '=dynamic'},
      link: function postLink(scope, element, attrs) {
        scope.$watch( 'attrs.dynamic' , function(html){

Try this element.html(scope.dynamic); than element.html(attr.dynamic);

how to check the dtype of a column in python pandas

I know this is a bit of an old thread but with pandas 19.02, you can do:


JPQL SELECT between date statement

public List<Student> findStudentByReports(Date startDate, Date endDate) {
    System.out.println("call findStudentMethd******************with this pattern"
                    + startDate
                    + endDate
                    + "*********************************************");

    return em
                    "' select attendence from Attendence attendence where attendence.admissionDate BETWEEN : startDate '' AND endDate ''"
                            + "'")
            .setParameter("startDate", startDate, TemporalType.DATE)
            .setParameter("endDate", endDate, TemporalType.DATE)


Git reset single file in feature branch to be the same as in master

you are almost there; you just need to give the reference to master; since you want to get the file from the master branch:

git checkout master -- filename

Note that the differences will be cached; so if you want to see the differences you obtained; use

git diff --cached

UTF-8 problems while reading CSV file with fgetcsv

In my case the source file has windows-1250 encoding and iconv prints tons of notices about illegal characters in input string...

So this solution helped me a lot:

 * getting CSV array with UTF-8 encoding
 * @param   resource    &$handle
 * @param   integer     $length
 * @param   string      $separator
 * @return  array|false
private function fgetcsvUTF8(&$handle, $length, $separator = ';')
    if (($buffer = fgets($handle, $length)) !== false)
        $buffer = $this->autoUTF($buffer);
        return str_getcsv($buffer, $separator);
    return false;

 * automatic convertion windows-1250 and iso-8859-2 info utf-8 string
 * @param   string  $s
 * @return  string
private function autoUTF($s)
    // detect UTF-8
    if (preg_match('#[\x80-\x{1FF}\x{2000}-\x{3FFF}]#u', $s))
        return $s;

    // detect WINDOWS-1250
    if (preg_match('#[\x7F-\x9F\xBC]#', $s))
        return iconv('WINDOWS-1250', 'UTF-8', $s);

    // assume ISO-8859-2
    return iconv('ISO-8859-2', 'UTF-8', $s);

Response to @manvel's answer - use str_getcsv instead of explode - because of cases like this:


explode will explode string into parts:


but str_getcsv will explode string into parts:


Set disable attribute based on a condition for Html.TextBoxFor

If you don't use html helpers you may use simple ternary expression like this:

<input name="Field"
       value="@Model.Field" tabindex="0"
       @(Model.IsDisabledField ? "disabled=\"disabled\"" : "")>

How to create a connection string in c#

string connectionstring="DataSource=severname;InitialCatlog=databasename;Uid=; password=;"
SqlConnection con=new SqlConnection(connectionstring)

WAMP Server doesn't load localhost

I faced a similar problem. I tried everything with ports, hosts and config files.But nothing helped.

I checked apache error logs. They showed the following error

(OS 10038)An operation was attempted on something that is not a socket.  : AH00332: winnt_accept: getsockname error on listening socket, is IPv6 available?

Finally this is what solved my problem.

1) Goto command prompt and run it in administrative mode. In windows 7 you can do it by typing cmd in run and then pressing ctrl+shift+enter

2) run the following command: netsh winsock reset

3) Restart the system

Display DateTime value in dd/mm/yyyy format in Asp.NET MVC

Or just use this in your View(Razor page)


I recommend that don't add date format in your model class

Html: Difference between cell spacing and cell padding

cellspacing and cell padding

Cell padding

is used for formatting purpose which is used to specify the space needed between the edges of the cells and also in the cell contents. The general format of specifying cell padding is as follows:

< table width="100" border="2" cellpadding="5">

The above adds 5 pixels of padding inside each cell .

Cell Spacing:

Cell spacing is one also used f formatting but there is a major difference between cell padding and cell spacing. It is as follows: Cell padding is used to set extra space which is used to separate cell walls from their contents. But in contrast cell spacing is used to set space between cells.

Radio buttons and label to display in same line

I always avoid using float:left but instead I use display: inline

.wrapper-class input[type="radio"] {_x000D_
  width: 15px;_x000D_
.wrapper-class label {_x000D_
  display: inline;_x000D_
  margin-left: 5px;_x000D_
<div class="wrapper-class">_x000D_
  <input type="radio" id="radio1">_x000D_
  <label for="radio1">Test Radio</label>_x000D_

Detecting an "invalid date" Date instance in JavaScript

If you use io-ts, you can use the decoder DateFromISOString directly.

import { DateFromISOString } from 'io-ts-types/lib/DateFromISOString'

const decoded = DateFromISOString.decode('2020-05-13T09:10:50.957Z')

Rendering raw html with reactjs

export class ModalBody extends Component{
        var rawMarkup = this.props.content
        return { __html: rawMarkup };
                <div className="modal-body">
                     <span dangerouslySetInnerHTML={this.rawMarkup()} />


iOS 10: "[App] if we're in the real pre-commit handler we can't actually add any new fences due to CA restriction"

To fix, I deleted the app from Simulator.

I also ran Clean first.

I do not think anything orientation-related triggered it. The biggest thing that changed before this symptom started is that a Swift framework started calling NSLog on worker threads instead of main thread.

Aren't Python strings immutable? Then why does a + " " + b work?

Python string objects are immutable. Example:

>>> a = 'tanim'
>>> 'Address of a is:{}'.format(id(a))
'Address of a is:64281536'
>>> a = 'ahmed'
>>> 'Address of a is:{}'.format(id(a))
'Address of a is:64281600'

In this example we can see that when we assign different value in a it doesn't modify.A new object is created.
And it can't be modified. Example:

  >>> a[0] = 'c'
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    **TypeError**: 'str' object does not support item assignment

A error occurs.

Count the number of occurrences of a string in a VARCHAR field?

In SQL SERVER, this is the answer

Declare @t table(TITLE VARCHAR(100), DESCRIPTION VARCHAR(100))

INSERT INTO @t SELECT 'test1', 'value blah blah value' 
INSERT INTO @t SELECT 'test2','value test' 
INSERT INTO @t SELECT 'test3','test test test' 
INSERT INTO @t SELECT 'test4','valuevaluevaluevaluevalue' 




TITLE   DESCRIPTION               Count
test1   value blah blah value        2
test2   value test                   1
test3   test test test               0
test4   valuevaluevaluevaluevalue    5

I don't have MySQL install, but goggled to find the Equivalent of LEN is LENGTH while REPLACE is same.

So the equivalent query in MySql should be

FROM <yourTable>

Please let me know if it worked for you in MySql also.

IN-clause in HQL or Java Persistence Query Language

Are you using Hibernate's Query object, or JPA? For JPA, it should work fine:

String jpql = "from A where name in (:names)";
Query q = em.createQuery(jpql);
q.setParameter("names", l);

For Hibernate's, you'll need to use the setParameterList:

String hql = "from A where name in (:names)";
Query q = s.createQuery(hql);
q.setParameterList("names", l);

How do I display image in Alert/confirm box in Javascript?

Alert boxes in JavaScript can only display pure text. You could use a JavaScript library like jQuery to display a modal instead?

This might be useful:

You can do it like this:

<!doctype html>

<html lang="en">
  <meta charset="utf-8" />
  <title>jQuery UI Dialog - Default functionality</title>
  <link rel="stylesheet" href="" />
  <script src=""></script>
  <script src=""></script>
  body {
    font-family: "Trebuchet MS", "Helvetica", "Arial",  "Verdana", "sans-serif";
    font-size: 62.5%;

  $(function() {
    $( "#dialog" ).dialog();

<div id="dialog" title="Basic dialog">
  <img src="" alt="Placeholder Image" />



Sending multipart/formdata with jQuery.ajax

If the file input name indicates an array and flags multiple, and you parse the entire form with FormData, it is not necessary to iteratively append() the input files. FormData will automatically handle multiple files.

$('#submit_1').on('click', function() {_x000D_
  let data = new FormData($("#my_form")[0]);_x000D_
    url: '/path/to/php_file',_x000D_
    type: 'POST',_x000D_
    data: data,_x000D_
    processData: false,_x000D_
    contentType: false,_x000D_
    success: function(r) {_x000D_
      console.log('success', r);_x000D_
    error: function(r) {_x000D_
      console.log('error', r);_x000D_
<script src=""></script>_x000D_
<form id="my_form">_x000D_
  <input type="file" name="multi_img_file[]" id="multi_img_file" accept=".gif,.jpg,.jpeg,.png,.svg" multiple="multiple" />_x000D_
  <button type="button" name="submit_1" id="submit_1">Not type='submit'</button>_x000D_

Note that a regular button type="button" is used, not type="submit". This shows there is no dependency on using submit to get this functionality.

The resulting $_FILES entry is like this in Chrome dev tools:

  error: (2) [0, 0]
  name: (2) ["pic1.jpg", "pic2.jpg"]
  size: (2) [1978036, 2446180]
  tmp_name: (2) ["/tmp/phphnrdPz", "/tmp/phpBrGSZN"]
  type: (2) ["image/jpeg", "image/jpeg"]

Note: There are cases where some images will upload just fine when uploaded as a single file, but they will fail when uploaded in a set of multiple files. The symptom is that PHP reports empty $_POST and $_FILES without AJAX throwing any errors. Issue occurs with Chrome 75.0.3770.100 and PHP 7.0. Only seems to happen with 1 out of several dozen images in my test set.

C# Iterate through Class properties

// the index of each item in fieldNames must correspond to 
// the correct index in resultItems
var fieldnames = new []{"itemtype", "etc etc "};

for (int e = 0; e < fieldNames.Length - 1; e++)
       .SetValue(newRecord, resultItems[e]);

Remove non-numeric characters (except periods and commas) from a string

I'm surprised there's been no mention of filter_var here for this being such an old question...

PHP has a built in method of doing this using sanitization filters. Specifically, the one to use in this situation is FILTER_SANITIZE_NUMBER_FLOAT with the FILTER_FLAG_ALLOW_FRACTION | FILTER_FLAG_ALLOW_THOUSAND flags. Like so:

$numeric_filtered = filter_var("AR3,373.31", FILTER_SANITIZE_NUMBER_FLOAT,
echo $numeric_filtered; // Will print "3,373.31"

It might also be worthwhile to note that because it's built-in to PHP, it's slightly faster than using regex with PHP's current libraries (albeit literally in nanoseconds).

TypeError: 'undefined' is not an object

try out this if you want to assign value to object and it is showing this error in angular..

crate object in construtor

this.modelObj = new Model(); //<---------- after declaring object above

How to place and center text in an SVG rectangle

SVG 1.2 Tiny added text wrapping, but most implementations of SVG that you will find in the browser (with the exception of Opera) have not implemented this feature. It's typically up to you, the developer, to position text manually.

The SVG 1.1 specification provides a good overview of this limitation, and the possible solutions to overcome it:

Each ‘text’ element causes a single string of text to be rendered. SVG performs no automatic line breaking or word wrapping. To achieve the effect of multiple lines of text, use one of the following methods:

  • The author or authoring package needs to pre-compute the line breaks and use multiple ‘text’ elements (one for each line of text).
  • The author or authoring package needs to pre-compute the line breaks and use a single ‘text’ element with one or more ‘tspan’ child elements with appropriate values for attributes ‘x’, ‘y’, ‘dx’ and ‘dy’ to set new start positions for those characters who start new lines. (This approach allows user text selection across multiple lines of text -- see Text selection and clipboard operations.)
  • Express the text to be rendered in another XML namespace such as XHTML [XHTML] embedded inline within a ‘foreignObject’ element. (Note: the exact semantics of this approach are not completely defined at this time.)

As a primitive, text wrapping can be simulated by using the dy attribute and tspan elements, and as mentioned in the spec, some tools can automate this. For example, in Inkscape, select the shape you want, and the text you want, and use Text -> Flow into Frame. This will allow you to write your text, with wrapping, which will wrap based on the bounds of the shape. Also, make sure you follow these instructions to tell Inkscape to maintain compatibility with SVG 1.1:

Furthermore, there are some JavaScript libraries that can be used to dynamically automate text wrapping:

It's interesting to note CSVG's solution to wrapping a shape to a text element (e.g. see their "button" example), although it's important to mention that their implementation is not usable in a browser:

I'm mentioning this because I have developed a CSVG-inspired library that allows you to do similar things and does work in web browsers, although I haven't released it yet.

jQuery $(document).ready and UpdatePanels?

In response to Brian MacKay's answer:

I inject the JavaScript into my page via the ScriptManager instead of putting it directly into the HTML of the UserControl. In my case, I need to scroll to a form that is made visible after the UpdatePanel has finished and returned. This goes in the code behind file. In my sample, I've already created the prm variable on the main content page.

private void ShowForm(bool pShowForm) {
    //other code here...
    if (pShowForm) {
        FocusOnControl(GetFocusOnFormScript(yourControl.ClientID), yourControl.ClientID);

private void FocusOnControl(string pScript, string pControlId) {
    ScriptManager.RegisterStartupScript(this.Page, this.Page.GetType(), "focusControl_" + pControlId, pScript, true);

/// <summary>
/// Scrolls to the form that is made visible
/// </summary>
/// <param name="pControlId">The ClientID of the control to focus on after the form is made visible</param>
/// <returns></returns>
private string GetFocusOnFormScript(string pControlId) {
    string script = @"
    function FocusOnForm() {
        var scrollToForm = $('#" + pControlId + @"').offset().top;
        $('html, body').animate({ 
            scrollTop: scrollToForm}, 
        /* This removes the event from the PageRequestManager immediately after the desired functionality is completed so that multiple events are not added */
    function ScrollFocusToFormCaller(sender, args) {
        if (args.get_error() == undefined) {
    return script;

What is the difference between cssSelector & Xpath and which is better with respect to performance for cross browser testing?

I’m going to hold the unpopular on SO selenium tag opinion that XPath is preferable to CSS in the longer run.

This long post has two sections - first I'll put a back-of-the-napkin proof the performance difference between the two is 0.1-0.3 milliseconds (yes; that's 100 microseconds), and then I'll share my opinion why XPath is more powerful.

Performance difference

Let's first tackle "the elephant in the room" – that xpath is slower than css.

With the current cpu power (read: anything x86 produced since 2013), even on browserstack/saucelabs/aws VMs, and the development of the browsers (read: all the popular ones in the last 5 years) that is hardly the case. The browser's engines have developed, the support of xpath is uniform, IE is out of the picture (hopefully for most of us). This comparison in the other answer is being cited all over the place, but it is very contextual – how many are running – or care about – automation against IE8?

If there is a difference, it is in a fraction of a millisecond.

Yet, most higher-level frameworks add at least 1ms of overhead over the raw selenium call anyways (wrappers, handlers, state storing etc); my personal weapon of choice – RobotFramework – adds at least 2ms, which I am more than happy to sacrifice for what it provides. A network roundtrip from an AWS us-east-1 to BrowserStack's hub is usually 11 milliseconds.

So with remote browsers if there is a difference between xpath and css, it is overshadowed by everything else, in orders of magnitude.

The measurements

There are not that many public comparisons (I've really seen only the cited one), so – here's a rough single-case, dummy and simple one.
It will locate an element by the two strategies X times, and compare the average time for that.

The target – BrowserStack's landing page, and its "Sign Up" button; a screenshot of the html as writing this post:

enter image description here

Here's the test code (python):

from selenium import webdriver
import timeit

if __name__ == '__main__':

    xpath_locator = '//div[@class="button-section col-xs-12 row"]'
    css_locator = 'div.button-section.col-xs-12.row'

    repetitions = 1000

    driver = webdriver.Chrome()

    css_time = timeit.timeit("driver.find_element_by_css_selector(css_locator)", 
                             number=repetitions, globals=globals())
    xpath_time = timeit.timeit('driver.find_element_by_xpath(xpath_locator)', 
                             number=repetitions, globals=globals())


    print("css total time {} repeats: {:.2f}s, per find: {:.2f}ms".
          format(repetitions, css_time, (css_time/repetitions)*1000))
    print("xpath total time for {} repeats: {:.2f}s, per find: {:.2f}ms".
          format(repetitions, xpath_time, (xpath_time/repetitions)*1000))

For those not familiar with Python – it opens the page, and finds the element – first with the css locator, then with the xpath; the find operation is repeated 1,000 times. The output is the total time in seconds for the 1,000 repetitions, and average time for one find in milliseconds.

The locators are:

  • for xpath – "a div element having this exact class value, somewhere in the DOM";
  • the css is similar – "a div element with this class, somewhere in the DOM".

Deliberately chosen not to be over-tuned; also, the class selector is cited for the css as "the second fastest after an id".

The environment – Chrome v66.0.3359.139, chromedriver v2.38, cpu: ULV Core M-5Y10 usually running at 1.5GHz (yes, a "word-processing" one, not even a regular i7 beast).

Here's the output:

css total time 1000 repeats: 8.84s, per find: 8.84ms

xpath total time for 1000 repeats: 8.52s, per find: 8.52ms

Obviously the per find timings are pretty close; the difference is 0.32 milliseconds. Don't jump "the xpath is faster" – sometimes it is, sometimes it's css.

Let's try with another set of locators, a tiny-bit more complicated – an attribute having a substring (common approach at least for me, going after an element's class when a part of it bears functional meaning):

xpath_locator = '//div[contains(@class, "button-section")]'
css_locator = 'div[class~=button-section]'

The two locators are again semantically the same – "find a div element having in its class attribute this substring".
Here are the results:

css total time 1000 repeats: 8.60s, per find: 8.60ms

xpath total time for 1000 repeats: 8.75s, per find: 8.75ms

Diff of 0.15ms.

As an exercise - the same test as done in the linked blog in the comments/other answer - the test page is public, and so is the testing code.

They are doing a couple of things in the code - clicking on a column to sort by it, then getting the values, and checking the UI sort is correct.
I'll cut it - just get the locators, after all - this is the root test, right?

The same code as above, with these changes in:

  • The url is now; there are 2 tests.

  • The locators for the first one - "Finding Elements By ID and Class" - are:

css_locator = '#table2 tbody .dues'
xpath_locator = "//table[@id='table2']//tr/td[contains(@class,'dues')]"

And here is the outcome:

css total time 1000 repeats: 8.24s, per find: 8.24ms

xpath total time for 1000 repeats: 8.45s, per find: 8.45ms

Diff of 0.2 milliseconds.

The "Finding Elements By Traversing":

css_locator = '#table1 tbody tr td:nth-of-type(4)'
xpath_locator = "//table[@id='table1']//tr/td[4]"

The result:

css total time 1000 repeats: 9.29s, per find: 9.29ms

xpath total time for 1000 repeats: 8.79s, per find: 8.79ms

This time it is 0.5 ms (in reverse, xpath turned out "faster" here).

So 5 years later (better browsers engines) and focusing only on the locators performance (no actions like sorting in the UI, etc), the same testbed - there is practically no difference between CSS and XPath.

So, out of xpath and css, which of the two to choose for performance? The answer is simple – choose locating by id.

Long story short, if the id of an element is unique (as it's supposed to be according to the specs), its value plays an important role in the browser's internal representation of the DOM, and thus is usually the fastest.

Yet, unique and constant (e.g. not auto-generated) ids are not always available, which brings us to "why XPath if there's CSS?"

The XPath advantage

With the performance out of the picture, why do I think xpath is better? Simple – versatility, and power.

Xpath is a language developed for working with XML documents; as such, it allows for much more powerful constructs than css.
For example, navigation in every direction in the tree – find an element, then go to its grandparent and search for a child of it having certain properties.
It allows embedded boolean conditions – cond1 and not(cond2 or not(cond3 and cond4)); embedded selectors – "find a div having these children with these attributes, and then navigate according to it".
XPath allows searching based on a node's value (its text) – however frowned upon this practice is, it does come in handy especially in badly structured documents (no definite attributes to step on, like dynamic ids and classes - locate the element by its text content).

The stepping in css is definitely easier – one can start writing selectors in a matter of minutes; but after a couple of days of usage, the power and possibilities xpath has quickly overcomes css.
And purely subjective – a complex css is much harder to read than a complex xpath expression.

Outro ;)

Finally, again very subjective - which one to chose?

IMO, there is no right or wrong choice - they are different solutions to the same problem, and whatever is more suitable for the job should be picked.

Being "a fan" of XPath I'm not shy to use in my projects a mix of both - heck, sometimes it is much faster to just throw a CSS one, if I know it will do the work just fine.

Environment Variable with Maven

Another solution would be to set MAVEN_OPTS (or other environment variables) in ${user.home}/.mavenrc (or %HOME%\mavenrc_pre.bat on windows).

Since Maven 3.3.1 there are new possibilities to set mvn command line parameters, if this is what you actually want:

  • ${maven.projectBasedir}/.mvn/maven.config
  • ${maven.projectBasedir}/.mvn/jvm.config

What are NR and FNR and what does "NR==FNR" imply?

Assuming you have Files a.txt and b.txt with

cat a.txt
cat b.txt

Keep in mind NR and FNR are awk built-in variables. NR - Gives the total number of records processed. (in this case both in a.txt and b.txt) FNR - Gives the total number of records for each input file (records in either a.txt or b.txt)

awk 'NR==FNR{a[$0];}{if($0 in a)print FILENAME " " NR " " FNR " " $0}' a.txt b.txt
a.txt 1 1 a
a.txt 2 2 b
a.txt 3 3 c
a.txt 4 4 d
a.txt 5 5 1
a.txt 6 6 3
a.txt 7 7 5
b.txt 8 1 a
b.txt 9 2 1

lets Add "next" to skip the first matched with NR==FNR

in b.txt and in a.txt

awk 'NR==FNR{a[$0];next}{if($0 in a)print FILENAME " " NR " " FNR " " $0}' a.txt b.txt
b.txt 8 1 a
b.txt 9 2 1

in b.txt but not in a.txt

 awk 'NR==FNR{a[$0];next}{if(!($0 in a))print FILENAME " " NR " " FNR " " $0}' a.txt b.txt
b.txt 10 3 2
b.txt 11 4 6
b.txt 12 5 7

awk 'NR==FNR{a[$0];next}!($0 in a)' a.txt b.txt

How to get row count using ResultSet in Java?

Others have already answered how to solve your problem, so I won't repeat what has already been said, but I will says this: you should probably figure out a way to solve your problems without knowing the result set count prior to reading through the results.

There are very few circumstances where the row count is actually needed prior to reading the result set, especially in a language like Java. The only case I think of where a row count would be necessary is when the row count is the only data you need(in which case a count query would be superior). Otherwise, you are better off using a wrapper object to represent your table data, and storing these objects in a dynamic container such as an ArrayList. Then, once the result set has been iterated over, you can get the array list count. For every solution that requires knowing the row count before reading the result set, you can probably think of a solution that does so without knowing the row count before reading without much effort. By thinking of solutions that bypass the need to know the row count before processing, you save the ResultSet the trouble of scrolling to the end of the result set, then back to the beginning (which can be a VERY expensive operation for large result sets).

Now of course I'm not saying there are never situations where you may need the row count before reading a result set. I'm just saying that in most circumstances, when people think they need the result set count prior to reading it, they probably don't, and it's worth taking 5 minutes to think about whether there is another way.

Just wanted to offer my 2 cents on the topic.

HTML form submit to PHP script

For your actual form, if you were to just post the results to your same page, it should probably work out all right. Try something like:

<form action=<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?> method="POST>

What's the best way to cancel event propagation between nested ng-click calls?

I like the idea of using a directive for this:

.directive('stopEvent', function () {
    return {
        restrict: 'A',
        link: function (scope, element, attr) {
            element.bind('click', function (e) {

Then use the directive like:

<div ng-controller="OverlayCtrl" class="overlay" ng-click="hideOverlay()">
    <img src="http://some_src" ng-click="nextImage()" stop-event/>

If you wanted, you could make this solution more generic like this answer to a different question:

Auto start node.js server on boot

If you are using Linux, macOS or Windows pm2 is your friend. It's a process manager that handle clusters very well.

You install it:

npm install -g pm2

Start a cluster of, for example, 3 processes:

 pm2 start app.js -i 3

And make pm2 starts them at boot:

 pm2 startup

It has an API, an even a monitor interface:


Go to github and read the instructions. It's easy to use and very handy. Best thing ever since forever.

Android "Only the original thread that created a view hierarchy can touch its views."

For the people struggling in Kotlin, it works like this:

lateinit var runnable: Runnable //global variable

 runOnUiThread { //Lambda
            runnable = Runnable {

                //do something here


 //you need to keep the handler outside the runnable body to work in kotlin
 fun runDelayedHandler(timeToWait: Long) {

        //Keep it running
        val handler = Handler()
        handler.postDelayed(runnable, timeToWait)

Zsh: Conda/Pip installs command not found

If anaconda is fully updated, a simple "conda init zsh" should work. Navigate into the anaconda3 folder using

cd /path/to/anaconda3/

of course replacing "/path/to/anaconda/" with "~/anaconda3" or "/anaconda3" or wherever the "anaconda3" folder is kept.

To make sure it's updated, run

./bin/conda update --prefix . anaconda

After this, running

./bin/conda init zsh

(or whatever shell you're using) will finish the job cleanly.

Change Spinner dropdown icon

You need to create custom background like this:

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

                    <gradient android:angle="90" android:endColor="#ffffff" android:startColor="#ffffff" android:type="linear"/>

                    <stroke android:width="1dp" android:color="#504a4b"/>

                    <corners android:radius="5dp"/>

                    <padding android:bottom="3dp" android:left="3dp" android:right="3dp" android:top="3dp"/>
                <bitmap android:gravity="bottom|right" android:src="@drawable/drop_down"/> // you can place your dropdown image


Then create style for spinner like this:

<style name="spinner_style">
        <item name="android:background">@drawable/YOURCUSTOMBACKGROUND</item>
        <item name="android:layout_marginLeft">5dp</item>
        <item name="android:layout_marginRight">5dp</item>
        <item name="android:layout_marginBottom">5dp</item>

after that apply this style to your spinner

How to provide animation when calling another activity in Android?

You must use OverridePendingTransition method to achieve it, which is in the Activity class. Sample Animations in the apidemos example's res/anim folder. Check it. More than check the demo in ApiDemos/App/Activity/animation.


public void onResume(){
    // TODO LC: preliminary support for views transitions
    this.overridePendingTransition(R.anim.in_from_right, R.anim.out_to_left);

Spring boot Security Disable security

Step 1: Comment annotation @EnableWebSecurity in your security config


Step 2: Add this to your file.


For more details look here:

Escape quote in web.config connection string

if &quot; isn't working then try &#34; instead.

space between divs - display table-cell

<div style="display:table;width:100%"  >
<div style="display:table-cell;width:49%" id="div1">

<!-- space between divs - display table-cell -->
<div style="display:table-cell;width:1%" id="separated"></div>
<!-- //space between divs - display table-cell -->

<div style="display:table-cell;width:50%" id="div2">

Visual Studio: ContextSwitchDeadlock

In Visual Studio 2017, unchecked the ContextSwitchDeadlock option by:

Debug > Windows > Exception Settings

enter image description here

In Exception Setting Windows: Uncheck the ContextSwitchDeadlock option

enter image description here

Changing Node.js listening port

I usually manually set the port that I am listening on in the app.js file (assuming you are using express.js

var server = app.listen(8080, function() {
    console.log('Ready on port %d', server.address().port);

This will log Ready on port 8080 to your console.

Dependency Injection vs Factory Pattern

In simple terms Dependency Injection vs Factory method implies push vs pull mechanism respectively.

Pull mechanism : class indirectly have dependency on Factory Method which in turn have dependency on concrete classes.

Push mechanism : Root component can be configured with all dependent components in a single location and thus promoting high maintenance and loose coupling.

With Factory method responsibility still lies with class (though indirectly) to create new object where as with dependency injection that responsibility is outsourced (at the cost of leaking abstraction though)

How can I return the difference between two lists?

First convert list to sets.

// create an empty set 
Set<T> set = new HashSet<>(); 

// Add each element of list into the set 
for (T t : list) 

You can use Sets.difference(Set1, Set2), which returns extra items present in Set1.
You can use Sets.difference(Set2, Set1), which returns extra items present in Set2.

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

UseParNewGC usually knowns as "parallel young generation collector" is same in all ways as the parallel garbage collector (-XX:+UseParallelGC), except that its more sophiscated and effiecient. Also it can be used with a "concurrent low pause collector".

See Java GC FAQ, question 22 for more information.

Note that there are some known bugs with UseParNewGC

programming a servo thru a barometer

You could define a mapping of air pressure to servo angle, for example:

def calc_angle(pressure, min_p=1000, max_p=1200):     return 360 * ((pressure - min_p) / float(max_p - min_p))  angle = calc_angle(pressure) 

This will linearly convert pressure values between min_p and max_p to angles between 0 and 360 (you could include min_a and max_a to constrain the angle, too).

To pick a data structure, I wouldn't use a list but you could look up values in a dictionary:

d = {1000:0, 1001: 1.8, ...}  angle = d[pressure] 

but this would be rather time-consuming to type out!

submitting a GET form with query string params and hidden params disappear

I usually write something like this:

foreach($_GET as $key=>$content){
        echo "<input type='hidden' name='$key' value='$content'/>";

This is working, but don't forget to sanitize your inputs against XSS attacks!

Sending cookies with postman

Enable intercepter in this way

Basically it is a chrome plug in. After installing the extention, you also need to make sure the extention is enabled from chrome side.

enter image description here

Create a tag in a GitHub repository

CAREFUL: In the command in Lawakush Kurmi's answer (git tag -a v1.0) the -a flag is used. This flag tells Git to create an annotated flag. If you don't provide the flag (i.e. git tag v1.0) then it'll create what's called a lightweight tag.

Annotated tags are recommended, because they include a lot of extra information such as:

  • the person who made the tag
  • the date the tag was made
  • a message for the tag

Because of this, you should always use annotated tags.

How to add a Try/Catch to SQL Stored Procedure

Error-Handling with SQL Stored Procedures

TRY/CATCH error handling can take place either within or outside of a procedure (or both). The examples below demonstrate error handling in both cases.

If you want to experiment further, you can fork the query on Stack Exchange Data Explorer.

(This uses a temporary stored procedure... we can't create regular SP's on SEDE, but the functionality is the same.)

--our Stored Procedure
create procedure #myProc as --we can only create #temporary stored procedures on SEDE. 
      print 'This is our Stored Procedure.'
      print 1/0                          --<-- generate a "Divide By Zero" error.
      print 'We are not going to make it to this line.'

      print 'This is the CATCH block within our Stored Procedure:'
          + ' Error Line #'+convert(varchar,ERROR_LINE())
          + ' of procedure '+isnull(ERROR_PROCEDURE(),'(Main)')
      --print 1/0                        --<-- generate another "Divide By Zero" error.
        -- uncomment the line above to cause error within the CATCH ¹ 

--our MAIN code block:
  print 'This is our MAIN Procedure.'
  execute #myProc  --execute the Stored Procedure
      --print 1/0                        --<-- generate another "Divide By Zero" error.
        -- uncomment the line above to cause error within the MAIN Procedure ²
  print 'Now our MAIN sql code block continues.'

  print 'This is the CATCH block for our MAIN sql code block:'
          + ' Error Line #'+convert(varchar,ERROR_LINE())
          + ' of procedure '+isnull(ERROR_PROCEDURE(),'(Main)')

Here's the result of running the above sql as-is:

This is our MAIN Procedure.
This is our Stored Procedure.
This is the CATCH block within our Stored Procedure: Error Line #5 of procedure #myProc
Now our MAIN sql code block continues.

¹ Uncommenting the "additional error line" from the Stored Procedure's CATCH block will produce:

This is our MAIN procedure.
This is our Stored Procedure.
This is the CATCH block within our Stored Procedure: Error Line #5 of procedure #myProc
This is the CATCH block for our MAIN sql code block: Error Line #13 of procedure #myProc

² Uncommenting the "additional error line" from the MAIN procedure will produce:

This is our MAIN Procedure.
This is our Stored Pprocedure.
This is the CATCH block within our Stored Procedure: Error Line #5 of procedure #myProc
This is the CATCH block for our MAIN sql code block: Error Line #4 of procedure (Main)

Use a single procedure for error handling

On topic of stored procedures and error handling, it can be helpful (and tidier) to use a single, dynamic, stored procedure to handle errors for multiple other procedures or code sections.

Here's an example:

--our error handling procedure
create procedure #myErrorHandling as
    print ' Error #'+convert(varchar,ERROR_NUMBER())+': '+ERROR_MESSAGE()  
    print ' occurred on line #'+convert(varchar,ERROR_LINE())
         +' of procedure '+isnull(ERROR_PROCEDURE(),'(Main)')
    if ERROR_PROCEDURE() is null       --check if error was in MAIN Procedure
      print '*Execution cannot continue after an error in the MAIN Procedure.'

create procedure #myProc as     --our test Stored Procedure
      print 'This is our Stored Procedure.'
      print 1/0                       --generate a "Divide By Zero" error.
      print 'We will not make it to this line.'
     execute #myErrorHandling

BEGIN TRY                       --our MAIN Procedure
  print 'This is our MAIN Procedure.'
  execute #myProc                     --execute the Stored Procedure
  print '*The error halted the procedure, but our MAIN code can continue.'
  print 1/0                           --generate another "Divide By Zero" error.
  print 'We will not make it to this line.'
  execute #myErrorHandling

Example Output: (This query can be forked on SEDE here.)

This is our MAIN procedure.
This is our stored procedure.
 Error #8134: Divide by zero error encountered.
 occurred on line #5 of procedure #myProc
*The error halted the procedure, but our MAIN code can continue.
 Error #8134: Divide by zero error encountered.
 occurred on line #5 of procedure (Main)
*Execution cannot continue after an error in the MAIN procedure.


In the scope of a TRY/CATCH block, the following system functions can be used to obtain information about the error that caused the CATCH block to be executed:

  • ERROR_NUMBER() returns the number of the error.
  • ERROR_SEVERITY() returns the severity.
  • ERROR_STATE() returns the error state number.
  • ERROR_PROCEDURE() returns the name of the stored procedure or trigger where the error occurred.
  • ERROR_LINE() returns the line number inside the routine that caused the error.
  • ERROR_MESSAGE() returns the complete text of the error message. The text includes the values supplied for any substitutable parameters, such as lengths, object names, or times.


Note that there are two types of SQL errors: Terminal and Catchable. TRY/CATCH will [obviously] only catch the "Catchable" errors. This is one of a number of ways of learning more about your SQL errors, but it probably the most useful.

It's "better to fail now" (during development) compared to later because, as Homer says . . .

How do you find out which version of GTK+ is installed on Ubuntu?

This isn't so difficult.

Just check your gtk+ toolkit utilities version from terminal:

gtk-launch --version

Error Running React Native App From Terminal (iOS)

For me, it turns out that there was an iOS system update pending asking to restart the computer. Restart and let the update finish solved my problem.

Are all Spring Framework Java Configuration injection examples buggy?

In your test, you are comparing the two TestParent beans, not the single TestedChild bean.

Also, Spring proxies your @Configuration class so that when you call one of the @Bean annotated methods, it caches the result and always returns the same object on future calls.

See here:

Business logic in MVC

Why don't you introduce a service layer. then your controller will be lean and more readable, then your all controller functions will be pure actions. you can decompose business logic as you much as you need within service layer . code reusability is hight . no impact on models and repositories.

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

Since the introduction of interaction media features you simply can do:

if(window.matchMedia("(pointer: coarse)").matches) {
    // touchscreen

Update (due to comments): The above solution is to detect if a "coarse pointer" - usually a touch screen - is the primary input device. In case you want to dectect if a device with e.g. a mouse also has a touch screen you may use any-pointer: coarse instead.

For more information have a look here: Detecting that the browser has no mouse and is touch-only

What is the difference between a mutable and immutable string in C#?

None, actually. The String class is mutable.

    string foo = string.Copy("I am immutable.");
    fixed (char* pChar = foo)
        char* pFoo = pChar;

        pFoo[5] = ' ';
        pFoo[6] = ' ';

    Console.WriteLine(foo); // "I am   mutable."

This kind of logic is done all the time in the String and StringBuilder classes, actually. They just allocate a new string each time you call Concat, Substring, etc. and use pointer arithmetic to copy over to the new string. Strings just don't mutate themselves, hence why they are considered "immutable".

By the way, do not attempt this with string literals or you will badly mess up your program:

string bar = "I am a string.";

fixed (char* pChar = bar)
    char* pBar = pChar;

    pBar[2] = ' ';

string baz = "I am a string.";

Console.WriteLine(baz); // "I  m a string."

This is because string literals are interned in the desktop .NET Framework; in other words, bar and baz point to the exact same string, so mutating one will mutate the other. This is all fine and dandy though if you're using an unmanaged platform like WinRT, which lacks string interning.

Current timestamp as filename in Java

You can use DateTime

import org.joda.time.DateTime

Option 1 : with yyyyMMddHHmmss"yyyyMMddHHmmss")

Will give 20190205214430

Option 2 : yyyy-dd-M--HH-mm-ss"yyyy-dd-M--HH-mm-ss")

will give 2019-05-2--21-43-32

How to Navigate from one View Controller to another using Swift

In swift 4.0

var viewController: UIViewController? = storyboard().instantiateViewController(withIdentifier: "Identifier")
var navi = UINavigationController(rootViewController: viewController!)
navigationController?.pushViewController(navi, animated: true)

How to compare timestamp dates with date-only parameter in MySQL?

Use a conversion function of MYSQL :

SELECT * FROM table WHERE DATE(timestamp) = '2012-05-05' 

This should work

Managing large binary files with Git

I would use submodules (as Pat Notz) or two distinct repositories. If you modify your binary files too often, then I would try to minimize the impact of the huge repository cleaning the history:

I had a very similar problem several months ago: ~21 GB of MP3 files, unclassified (bad names, bad id3's, don't know if I like that MP3 file or not...), and replicated on three computers.

I used an external hard disk drive with the main Git repository, and I cloned it into each computer. Then, I started to classify them in the habitual way (pushing, pulling, merging... deleting and renaming many times).

At the end, I had only ~6 GB of MP3 files and ~83 GB in the .git directory. I used git-write-tree and git-commit-tree to create a new commit, without commit ancestors, and started a new branch pointing to that commit. The "git log" for that branch only showed one commit.

Then, I deleted the old branch, kept only the new branch, deleted the ref-logs, and run "git prune": after that, my .git folders weighted only ~6 GB...

You could "purge" the huge repository from time to time in the same way: Your "git clone"'s will be faster.

Creating a comma separated list from IList<string> or IEnumerable<string>

FYI, the .NET 4.0 version of string.Join() has some extra overloads, that work with IEnumerable instead of just arrays, including one that can deal with any type T:

public static string Join(string separator, IEnumerable<string> values)
public static string Join<T>(string separator, IEnumerable<T> values)

Listview Scroll to the end of the list after updating the list

The simplest solution is :


Show hidden div on ng-click within ng-repeat

Use ng-show and toggle the value of a show scope variable in the ng-click handler.

Here is a working example:

<ul class="procedures">
    <li ng-repeat="procedure in procedures">
        <h4><a href="#" ng-click="show = !show">{{procedure.definition}}</a></h4>
         <div class="procedure-details" ng-show="show">
            <p>Number of patient discharges: {{procedure.discharges}}</p>
            <p>Average amount covered by Medicare: {{procedure.covered}}</p>
            <p>Average total payments: {{procedure.payments}}</p>

Check if a value is in an array or not with Excel VBA

I would like to provide another variant that should be both performant and powerful, because


'-1 if not found
Public Function IsInArray( _
  item As Variant, _
  arr As Variant, _
  Optional nthOccurrence As Long = 1 _
  ) As Long

    IsInArray = -1

    Dim i As Long:  For i = LBound(arr, 1) To UBound(arr, 1)
        If arr(i) = item Then
            If nthOccurrence > 1 Then
                nthOccurrence = nthOccurrence - 1
                GoTo continue
            End If
            IsInArray = i
            Exit Function
        End If
    Next i

End Function

use it like this:

Sub testInt()
  Debug.Print IsInArray(2, Array(1, 2, 3))  '=> 1
End Sub

Sub testString1()
  Debug.Print IsInArray("b", Array("a", "b", "c", "a"))  '=> 1
End Sub

Sub testString2()
  Debug.Print IsInArray("b", Array("a", "b", "c", "b"), 2)  '=> 3
End Sub

Sub testBool1()
  Debug.Print IsInArray(False, Array(True, False, True))  '=> 1
End Sub

Sub testBool2()
  Debug.Print IsInArray(True, Array(True, False, True), 2)  '=> 2
End Sub

Excel: the Incredible Shrinking and Expanding Controls

This has been plaguing me for years, on and off. There are a number of fixes around, but they seem hit and miss. It was still occurring in Excel 2010 (happening to me May 2014), and is still occurring in Excel 2013 by some reports. The best description I have found that matches my situation at least (Excel 2010, no RDP involved, no Print Preview involved) is here:

Microsoft Excel Support Team Blog: ActiveX and form controls resize themselves when clicked or doing a print preview (in Excel 2010)

(This might not help for users of Excel 2013 sorry)

EDIT: Adding detail in case technet link ever goes dead, the technet article says:

FIRSTLY install Microsoft Hotfix 2598144 for Excel 2010, available: here.

SECONDLY, if your symptom is "An ActiveX button changes to the incorrect size after you click it in an Excel 2010 worksheet", then you should:

  • Click Start, click Run, type regedit in the Open box, and then click OK.
  • Locate and then select the following registry subkey HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Excel\Options
  • On the Edit menu, point to New, and then click DWORD (32-bit) value.
  • Type LegacyAnchorResize, and then press Enter.
  • In the Details pane, right-click LegacyAnchorResize, and then click Modify.
  • In the Value data box, type 1, and then click OK.
  • Exit Registry Editor.

OR SECONDLY, if your symptom is "A button form control is displayed incorrectly in a workbook after you view the print preview of the workbook in Excel 2010", then you should:

  • Click Start, click Run, type regedit in the Open box, and then click OK.
  • Locate and then select the following registry subkey: HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Excel\Options
  • On the Edit menu, point to New, and then click DWORD (32-bit) value.
  • Type MultiSheetPrint, and then press Enter.
  • In the Details pane, right-click MultiSheetPrint, and then click Modify.
  • In the Value data box, type 1, and then click OK.
  • Select the following registry subkey again: HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Excel\Options
  • On the Edit menu, point to New, and then click DWORD (32-bit) value.
  • Type LegacyAnchorResize, and then press Enter.
  • In the Details pane, right-click LegacyAnchorResize, and then click Modify.
  • In the Value data box, type 1, and then click OK.
  • Exit Registry Editor.

OR SECONDLY, if your symptom is "An ActiveX button is changed to an incorrect size in an Excel 2010 worksheet after you view the print preview of the worksheet", then you should:

  • Click Start, click Run, type regedit in the Open box, and then click OK.
  • Locate and then select the following registry subkey: HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Excel\Options
  • On the Edit menu, point to New, and then click DWORD (32-bit) value.
  • Type LegacyAnchorResize, and then press Enter.
  • In the Details pane, right-click LegacyAnchorResize, and then click Modify.
  • In the Value data box, type 1, and then click OK.
  • Exit Registry Editor.

Good luck. This issue is such a pain...

How to change the DataTable Column Name?


dt.Columns["Name"].ColumnName = "xyz";


dt.Columns[0].ColumnName = "xyz";

How to include() all PHP files from a directory?

How to do this in 2017:

spl_autoload_register( function ($class_name) {
    $CLASSES_DIR = __DIR__ . DIRECTORY_SEPARATOR . 'classes' . DIRECTORY_SEPARATOR;  // or whatever your directory is
    $file = $CLASSES_DIR . $class_name . '.php';
    if( file_exists( $file ) ) include $file;  // only include if file exists, otherwise we might enter some conflicts with other pieces of code which are also using the spl_autoload_register function
} );

Recommended by PHP documentation here: Autoloading classes

symfony2 : failed to write cache directory

Maybe you forgot to change the permissions of app/cache app/log

I'm using Ubuntu so

sudo chmod -R 777 app/cache
sudo chmod -R 777 app/logs
sudo setfacl -dR -m u::rwX app/cache app/logs

Hope it helps..

How to convert CharSequence to String?

You can directly use String.valueOf()


Though this is same as toString() it does a null check on the charSequence before actually calling toString.

This is useful when a method can return either a charSequence or null value.

Upload video files via PHP and save them in appropriate folder and have a database entry

"Could you suggest a simpler code main thing is uploading the file Data base entry is secondary"

^--- As per OP's request. ---^

Image and video uploading code (tested with PHP Version 5.4.17)

HTML form

<!DOCTYPE html>



<form action="upload_file.php" method="post" enctype="multipart/form-data">
<label for="file"><span>Filename:</span></label>
<input type="file" name="file" id="file" /> 
<br />
<input type="submit" name="submit" value="Submit" />


PHP handler (upload_file.php)

Change upload folder to preferred name. Presently saves to upload/


$allowedExts = array("jpg", "jpeg", "gif", "png", "mp3", "mp4", "wma");
$extension = pathinfo($_FILES['file']['name'], PATHINFO_EXTENSION);

if ((($_FILES["file"]["type"] == "video/mp4")
|| ($_FILES["file"]["type"] == "audio/mp3")
|| ($_FILES["file"]["type"] == "audio/wma")
|| ($_FILES["file"]["type"] == "image/pjpeg")
|| ($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg"))

&& ($_FILES["file"]["size"] < 20000)
&& in_array($extension, $allowedExts))

  if ($_FILES["file"]["error"] > 0)
    echo "Return Code: " . $_FILES["file"]["error"] . "<br />";
    echo "Upload: " . $_FILES["file"]["name"] . "<br />";
    echo "Type: " . $_FILES["file"]["type"] . "<br />";
    echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
    echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />";

    if (file_exists("upload/" . $_FILES["file"]["name"]))
      echo $_FILES["file"]["name"] . " already exists. ";
      "upload/" . $_FILES["file"]["name"]);
      echo "Stored in: " . "upload/" . $_FILES["file"]["name"];
  echo "Invalid file";

Unique constraint on multiple columns

USE [TSQL2012]

/****** Object:  Table [dbo].[Table_1]    Script Date: 11/22/2015 12:45:47 PM ******/


CREATE TABLE [dbo].[Table_1](
    [seq] [bigint] IDENTITY(1,1) NOT NULL,
    [ID] [int] NOT NULL,
    [name] [nvarchar](50) NULL,
    [cat] [nvarchar](50) NULL,
    [ID] ASC
    [name] ASC,
    [cat] ASC


Best practices for adding .gitignore file for Python projects?

When using buildout I have following in .gitignore (along with *.pyo and *.pyc):


Thanks to Jacob Kaplan-Moss

Also I tend to put .svn in since we use several SCM-s where I work.

Bootstrap 3: How to get two form inputs on one line and other inputs on individual lines?

I resorted to creating 2 style cascades using inline-block for input that pretty much override the field:

.input-sm {
    height: 2.1em;
    display: inline-block;

and a series of fixed sizes as opposed to %

.input-10 {
    width: 10em;

.input-32 {
    width: 32em;

Using numpy to build an array of all combinations of two arrays

Here's yet another way, using pure NumPy, no recursion, no list comprehension, and no explicit for loops. It's about 20% slower than the original answer, and it's based on np.meshgrid.

def cartesian(*arrays):
    mesh = np.meshgrid(*arrays)  # standard numpy meshgrid
    dim = len(mesh)  # number of dimensions
    elements = mesh[0].size  # number of elements, any index will do
    flat = np.concatenate(mesh).ravel()  # flatten the whole meshgrid
    reshape = np.reshape(flat, (dim, elements)).T  # reshape and transpose
    return reshape

For example,

x = np.arange(3)
a = cartesian(x, x, x, x, x)


[[0 0 0 0 0]
 [0 0 0 0 1]
 [0 0 0 0 2]
 [2 2 2 2 0]
 [2 2 2 2 1]
 [2 2 2 2 2]]

Download and install an ipa from self hosted url on iOS

To distribute your app over-the-air (OTA, this means without using TestFlight or the official App Store), you may need to create 3 different files, namely:

  • The .ipa file (using an ad-hoc provisioning profile)
  • index.html
  • manifest.plist

You can use Beta Builder to generate these files:

  1. Archive your build.
  2. Save the .ipa on the Desktop.
  3. Download a small utility Beta Builder from here. This does most of the required task.
  4. Open the tool and select your .ipa file, then provide the path you will be placing the build on in the beta builder.
  5. Generate all the files.
  6. Now upload index.html, your_App.ipa, & manifest.plist to your server path
  7. Now share the link of index.html. Once you open this file, you will be asked to Tap on install.
  8. It will install your_App.ipa on your device.

You can also do this more manually.


<a href="itms-services://?action=download-manifest&url=">Install App</a>


<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "">
<plist version="1.0">
                <string>YOUR APP NAME</string>

If the app refuses to install or run, you may need to check the following items:

  • The provisioning profile you've used when compiling/archiving your app
  • The URLs in both index.html and manifest.plist
  • The plist file may possibly need to be hosted on an HTTPS server. You can use Dropbox for this if necessary.
  • Your device UUIDs may need to be registered inside Apple Developer Center unless you have an Enterprise licence
  • You may need to manually enable access to the app within Settings > Profiles

Convert into a useable string using Arduino?

This would be way easier:

char data [21];
int number_of_bytes_received;

if(Serial.available() > 0)
    number_of_bytes_received = Serial.readBytesUntil (13,data,20); // read bytes (max. 20) from buffer, untill <CR> (13). store bytes in data. count the bytes recieved.
    data[number_of_bytes_received] = 0; // add a 0 terminator to the char array

bool result = strcmp (data, "whatever");
// strcmp returns 0; if inputs match.

if (result == 0)
   Serial.println("data matches whatever");
   Serial.println("data does not match whatever");

Simple tool to 'accept theirs' or 'accept mine' on a whole file using git

Try this:

To accept theirs changes: git merge --strategy-option theirs

To accept yours: git merge --strategy-option ours

How to prevent default event handling in an onclick method?

Just place "javascript:void(0)", in place of "#" in href tag

<a href="javascript:void(0);" onclick="callmymethod(24)">Call</a>

CSS @font-face not working with Firefox, but working with Chrome and IE

Because of that this is one of the top Google results for this problem I would like to add what solved this problem for me:

I had to remove the format(opentype) from the src of the font-face, then it worked in Firefox as well. It worked fine in Chrome and Safari before that.

Why am I getting "Received fatal alert: protocol_version" or "peer not authenticated" from Maven Central?

Solution 1: configure Java 7

It is need to enable TLS 1.2 protocol with Java property in the command line

mvn -Dhttps.protocols=TLSv1.2 install

install is just an example of a goal

The same error for ant can be solved by this way

java -Dhttps.protocols=TLSv1.2 -cp %ANT_HOME%/lib/ant-launcher.jar

Solution 2: use Java 7 with Oracle Advanced Support

Also problem can be solved by updating the Java 7 version. But the last available version (7u80) doesn't fix the problem. It is need to use an update provided with Oracle Advanced Support (formerly known as Java for Business).

Solution 3: use Java 8 instead

Configure $JAVA_HOME to point to Java 8.

Multiplying Two Columns in SQL Server

select InitialPayment * MonthlyPayRate as SomeRandomCalculation from Payment

Deep copy in ES6 using the spread syntax

const cloneData = (dataArray) => {
    newData= []
    dataArray.forEach((value) => {
    return newData
  • a = [{name:"siva"}, {name:"siva1"}] ;
  • b = myCopy(a)
  • b === a // false`

Eclipse interface icons very small on high resolution screen in Windows 8.1

The best way is to edit the exe manifest with something like resource tuner and add

    <application xmlns="urn:schemas-microsoft-com:asm.v3"><windowsSettings><ms_windowsSettings:dpiAware xmlns:ms_windowsSettings="" xmlns="">false</ms_windowsSettings:dpiAware></windowsSettings></application>        

after dependency to set the exe as dpi unaware. This way the program will be a little pixelated but it will be in a confortable size.

How can I create an MSI setup?

Look for Windows Installer XML (WiX)

How to style the <option> with only CSS?

There is no cross-browser way of styling option elements, certainly not to the extent of your second screenshot. You might be able to make them bold, and set the font-size, but that will be about it...

Linq on DataTable: select specific column into datatable, not whole table

Here I get only three specific columns from mainDataTable and use the filter

DataTable checkedParams = mainDataTable.Select("checked = true").CopyToDataTable()
.DefaultView.ToTable(false, "lagerID", "reservePeriod", "discount");

sql query to get earliest date

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

Running ASP.Net on a Linux based server

You might want to consider this guide that helps Windows developers port their code to Mono/Linux:

Guide: Porting ASP.NET Applications - Mono

Python: Binary To Decimal Conversion

You can use int casting which allows the base specification.

int(b, 2)  # Convert a binary string to a decimal int.

Reinitialize Slick js after successful ajax call

Note: I am not sure if this is correct but you can give it a try and see if this works.

There is a unslick method which de-initializes the carousel, so you might try using that before re-initializing it.

    type: 'get',
    url: '/public/index',
    dataType: 'script',
    data: data_send,
    success: function() {
        $('.skills_section').unslick();  // destroy the previous instance

Hope this helps.

How do I fetch multiple columns for use in a cursor loop?

Here is slightly modified version. Changes are noted as code commentary.


declare @cnt int
declare @test nvarchar(128)
-- variable to hold table name
declare @tableName nvarchar(255)
declare @cmd nvarchar(500) 
-- local means the cursor name is private to this code
-- fast_forward enables some speed optimizations
declare Tests cursor local fast_forward for

open Tests
-- Instead of fetching twice, I rather set up no-exit loop
while 1 = 1
  -- And then fetch
  fetch next from Tests into @test, @tableName
  -- And then, if no row is fetched, exit the loop
  if @@fetch_status <> 0
  -- Quotename is needed if you ever use special characters
  -- in table/column names. Spaces, reserved words etc.
  -- Other changes add apostrophes at right places.
  set @cmd = N'exec sp_rename ''' 
           + quotename(@tableName) 
           + '.' 
           + quotename(@test) 
           + N''',''' 
           + RIGHT(@test,LEN(@test)-3) 
           + '_Pct''' 
           + N', ''column''' 

  print @cmd

  EXEC sp_executeSQL @cmd

close Tests 
deallocate Tests


How can I get session id in php and show it?

In the PHP file first you need to register the session

 <? session_start();
     $_SESSION['id'] = $userData['user_id'];?>

And in each page of your php application you can retrive the session id

 <? session_start()
    id =  $_SESSION['id'];

How to get just the responsive grid from Bootstrap 3?

In Bootstrap 4, there are already separated files in their GitHub. You can find them here

IF... OR IF... in a windows batch file

It's possible to use a function, which evaluates the OR logic and returns a single value.

@echo off
set var1=3
set var2=5
call :logic_or orResult "'%var1%'=='4'" "'%var2%'=='5'"
if %orResult%==1 ( 
    echo At least one expression is true
) ELSE echo All expressions are false
exit /b

:logic_or <resultVar> expression1 [[expr2] ... expr-n] 
set "logic_or.result=0"
set "logic_or.resultVar=%~1"

if "%~2"=="" goto :logic_or_end 
if %~2 set "logic_or.result=1"
goto :logic_or_loop 

  set "%logic_or.resultVar%=%logic_or.result%"
  exit /b

Using HTML and Local Images Within UIWebView

Using relative paths or file: paths to refer to images does not work with UIWebView. Instead you have to load the HTML into the view with the correct baseURL:

NSString *path = [[NSBundle mainBundle] bundlePath];
NSURL *baseURL = [NSURL fileURLWithPath:path];
[webView loadHTMLString:htmlString baseURL:baseURL];

You can then refer to your images like this:

<img src="myimage.png">

(from uiwebview revisited)

Java, How to add values to Array List used as value in HashMap

Java 8+ has computeIfAbsent

examList.computeIfAbsent(map.get(id), k -> new ArrayList<>());

How to create folder with PHP code?

... You can then use copy() to duplicate a PHP file, although this sounds incredibly inefficient.

Case insensitive regular expression without re.compile?

Pass re.IGNORECASE to the flags param of search, match, or sub:'test', 'TeSt', re.IGNORECASE)
re.match('test', 'TeSt', re.IGNORECASE)
re.sub('test', 'xxxx', 'Testing', flags=re.IGNORECASE)

How do I find a default constraint using INFORMATION_SCHEMA?

I am using folllowing script to retreive all defaults (sp_binddefaults) and all default constraint with following scripts:

SELECT AS TableName, AS ColumnName, SC.COLUMN_DEFAULT AS DefaultValue, AS DefaultConstraintName
    sys.all_columns c
    JOIN sys.tables t ON c.object_id = t.object_id
    JOIN sys.schemas s ON t.schema_id = s.schema_id
    LEFT JOIN sys.default_constraints dc ON c.default_object_id = dc.object_id
    --WHERE = '' and = ''

" app-release.apk" how to change this default generated apk name

I think this will be helpful.

buildTypes {
    release {
        shrinkResources true
        minifyEnabled true
        proguardFiles getDefaultProguardFile('proguard-android.txt'), ''
        applicationVariants.all { variant ->
            variant.outputs.each { output ->
                project.ext { appName = 'MyAppName' }
                def formattedDate = new Date().format('yyyyMMddHHmmss')
                def newName =
                newName = newName.replace("app-", "$project.ext.appName-")
                newName = newName.replace("-release", "-release" + formattedDate)
                output.outputFile = new File(output.outputFile.parent, newName)
productFlavors {
    flavor1 {
    flavor2 {
        proguardFile ''

How to create JSON object using jQuery

var model = {"Id": "xx", "Name":"Ravi"};
$.ajax({    url: 'test/set',
                        type: "POST",
                        data: model,
                        success: function (res) {
                            if (res != null) {
                        error: function (res) {


How to debug Lock wait timeout exceeded on MySQL?

Due to the popularity of MySQL, there's no wonder Lock wait timeout exceeded; try restarting transaction exception gets so much attention on SO.

The more contention you have, the greater the chance of deadlocks, which a DB engine will resolve by time-outing one of the deadlocked transactions.

Also, long-running transactions that have modified (e.g. UPDATE or DELETE) a large number of entries are more likely to generate conflicts with other transactions.

Although InnoDB MVCC, you can still request explicit locks using the FOR UPDATE clause. However, unlike other popular DBs (Oracle, MSSQL, PostgreSQL, DB2), MySQL uses REPEATABLE_READ as the default isolation level.

Now, the locks that you acquired (either by modifying rows or using explicit locking), are held for the duration of the currently running transaction. If you want a good explanation of the difference between REPEATABLE_READ and READ COMMITTED in regards to locking, please read this Percona article.

In REPEATABLE READ every lock acquired during a transaction is held for the duration of the transaction.

In READ COMMITTED the locks that did not match the scan are released after the STATEMENT completes.


This means that in READ COMMITTED other transactions are free to update rows that they would not have been able to update (in REPEATABLE READ) once the UPDATE statement completes.

Therefore: The more restrictive the isolation level (REPEATABLE_READ, SERIALIZABLE) the greater the chance of deadlock. This is not an issue "per se", it's a trade-off.

You can get very good results with READ_COMMITED, as you need application-level lost update prevention when using logical transactions that span over multiple HTTP requests. The optimistic locking approach targets lost updates that might happen even if you use the SERIALIZABLE isolation level while reducing the lock contention by allowing you to use READ_COMMITED.

RegEx for valid international mobile phone number

Posting a note here for users looking into this into the future. Google's libphonenumber is what you most likely would want to use. There is wrappers for PHP, node.js, Java, etc. to use the data which Google has been collecting and reduces the requirements for maintaining large arrays of regex patterns to apply.

How do I collapse sections of code in Visual Studio Code for Windows?

With JavaScript:

//#region REGION_NAME
   ...code here

Best way to disable button in Twitter's Bootstrap

For input and button:

$('button').prop('disabled', true);

For anchor:

$('a').attr('disabled', true);

Checked in firefox, chrome.


ImportError: No module named Image

The PIL distribution is mispackaged for egg installation.

Install Pillow instead, the friendly PIL fork.

Where do I call the BatchNormalization function in Keras?

Batch Normalization is used to normalize the input layer as well as hidden layers by adjusting mean and scaling of the activations. Because of this normalizing effect with additional layer in deep neural networks, the network can use higher learning rate without vanishing or exploding gradients. Furthermore, batch normalization regularizes the network such that it is easier to generalize, and it is thus unnecessary to use dropout to mitigate overfitting.

Right after calculating the linear function using say, the Dense() or Conv2D() in Keras, we use BatchNormalization() which calculates the linear function in a layer and then we add the non-linearity to the layer using Activation().

from keras.layers.normalization import BatchNormalization
model = Sequential()
model.add(Dense(64, input_dim=14, init='uniform'))
model.add(BatchNormalization(epsilon=1e-06, mode=0, momentum=0.9, weights=None))
model.add(Dense(64, init='uniform'))
model.add(BatchNormalization(epsilon=1e-06, mode=0, momentum=0.9, weights=None))
model.add(Dense(2, init='uniform'))
model.add(BatchNormalization(epsilon=1e-06, mode=0, momentum=0.9, weights=None))

sgd = SGD(lr=0.1, decay=1e-6, momentum=0.9, nesterov=True)
model.compile(loss='binary_crossentropy', optimizer=sgd), y_train, nb_epoch=20, batch_size=16, show_accuracy=True, 
validation_split=0.2, verbose = 2)

How is Batch Normalization applied?

Suppose we have input a[l-1] to a layer l. Also we have weights W[l] and bias unit b[l] for the layer l. Let a[l] be the activation vector calculated(i.e. after adding the non-linearity) for the layer l and z[l] be the vector before adding non-linearity

  1. Using a[l-1] and W[l] we can calculate z[l] for the layer l
  2. Usually in feed-forward propagation we will add bias unit to the z[l] at this stage like this z[l]+b[l], but in Batch Normalization this step of addition of b[l] is not required and no b[l] parameter is used.
  3. Calculate z[l] means and subtract it from each element
  4. Divide (z[l] - mean) using standard deviation. Call it Z_temp[l]
  5. Now define new parameters ? and ß that will change the scale of the hidden layer as follows:

    z_norm[l] = ?.Z_temp[l] + ß

In this code excerpt, the Dense() takes the a[l-1], uses W[l] and calculates z[l]. Then the immediate BatchNormalization() will perform the above steps to give z_norm[l]. And then the immediate Activation() will calculate tanh(z_norm[l]) to give a[l] i.e.

a[l] = tanh(z_norm[l])

Google reCAPTCHA: How to get user response and validate in the server side?

The cool thing about the new Google Recaptcha is that the validation is now completely encapsulated in the widget. That means, that the widget will take care of asking questions, validating responses all the way till it determines that a user is actually a human, only then you get a g-recaptcha-response value.

But that does not keep your site safe from HTTP client request forgery.

Anyone with HTTP POST knowledge could put random data inside of the g-recaptcha-response form field, and foll your site to make it think that this field was provided by the google widget. So you have to validate this token.

In human speech it would be like,

  • Your Server: Hey Google, there's a dude that tells me that he's not a robot. He says that you already verified that he's a human, and he told me to give you this token as a proof of that.
  • Google: Hmm... let me check this token... yes I remember this dude I gave him this token... yeah he's made of flesh and bone let him through.
  • Your Server: Hey Google, there's another dude that tells me that he's a human. He also gave me a token.
  • Google: Hmm... it's the same token you gave me last time... I'm pretty sure this guy is trying to fool you. Tell him to get off your site.

Validating the response is really easy. Just make a GET Request to

And replace the response_string with the value that you earlier got by the g-recaptcha-response field.

You will get a JSON Response with a success field.

More information here:

Edit: It's actually a POST, as per documentation here.

What is the difference between ( for... in ) and ( for... of ) statements?

The for-in statement iterates over the enumerable properties of an object, in arbitrary order.

The loop will iterate over all enumerable properties of the object itself and those the object inherits from its constructor's prototype

You can think of it as "for in" basically iterates and list out all the keys.

var str = 'abc';
var arrForOf = [];
var arrForIn = [];

for(value of str){

for(value in str){

// ["a", "b", "c"]
// ["0", "1", "2", "formatUnicorn", "truncate", "splitOnLast", "contains"]

Send data from activity to fragment in Android

I would like to add for the beginners that the difference between the 2 most upvoted answers here is given by the different use of a fragment.

If you use the fragment within the java class where you have the data you want to pass, you can apply the first answer to pass data:

Bundle bundle = new Bundle();
bundle.putString("edttext", "From Activity");
Fragmentclass fragobj = new Fragmentclass();

If however you use for example the default code given by Android Studio for tabbed fragments, this code will not work.

It will not work even if you replace the default PlaceholderFragment with your FragmentClasses, and even if you correct the FragmentPagerAdapter to the new situation adding a switch for getItem() and another switch for getPageTitle() (as shown here)

Warning: the clip mentioned above has code errors, which I explain later here, but is useful to see how you go from default code to editable code for tabbed fragments)! The rest of my answer makes much more sense if you consider the java classes and xml files from that clip (representative for a first use of tabbed fragments by a beginner scenario).

The main reason the most upvoted answer from this page will not work is that in that default code for tabbed fragments, the fragments are used in another java class: FragmentPagerAdapter!

So, in order to send the data, you are tempted to create a bundle in the MotherActivity and pass it in the FragmentPagerAdapter, using answer no.2.

Only that is wrong again. (Probably you could do it like that, but it is just a complication which is not really needed).

The correct/easier way to do it, I think, is to pass the data directly to the fragment in question, using answer no.2. Yes, there will be tight coupling between the Activity and the Fragment, BUT, for tabbed fragments, that is kind of expected. I would even advice you to create the tabbed fragments inside the MotherActivity java class (as subclasses, as they will never be used outside the MotherActivity) - it is easy, just add inside the MotherActivity java class as many Fragments as you need like this:

 public static class Tab1 extends Fragment {

    public Tab1() {

    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.your_layout_name_for_fragment_1, container, false);
        return rootView;

So, to pass data from the MotherActivity to such a Fragment you will need to create private Strings/Bundles above the onCreate of your Mother activity - which you can fill with the data you want to pass to the fragments, and pass them on via a method created after the onCreate (here called getMyData()).

public class MotherActivity extends Activity {

    private String out;
    private Bundle results;

    protected void onCreate(Bundle savedInstanceState) {

       // for example get a value from the previous activity
        Intent intent = getIntent();
        out = intent.getExtras().getString("Key");


    public Bundle getMyData() {
        Bundle hm = new Bundle();
        return hm;

And then in the fragment class, you use getMyData:

public static class Tab1 extends Fragment {
         * The fragment argument representing the section number for this
         * fragment.
        public Tab1() {

        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.your_layout_name_for_fragment_1, container, false);
            TextView output = (TextView)rootView.findViewById(;

            MotherActivity activity = (MotherActivity)getActivity();

            Bundle results = activity.getMyData();
            String value1 = results.getString("val1");

            return rootView;

If you have database queries I advice you to do them in the MotherActivity (and pass their results as Strings/Integers attached to keys inside a bundle as shown above), as inside the tabbed fragments, your syntax will become more complex (this becomes getActivity() for example, and getIntent becomes getActivity().getIntent), but you have also the option to do as you wish.

My advice for beginners is to focus on small steps. First, get your intent to open a very simple tabbed activity, without passing ANY data. Does it work? Does it open the tabs you expect? If not, why?

Start from that, and by applying solutions such as those presented in this clip, see what is missing. For that particular clip, the mainactivity.xml is never shown. That will surely confuse you. But if you pay attention, you will see that for example the context (tools:context) is wrong in the xml fragment files. Each fragment XML needs to point to the correct fragment class (or subclass using the separator $).

You will also see that in the main activity java class you need to add tabLayout.setupWithViewPager(mViewPager) - right after the line TabLayout tabLayout = (TabLayout) findViewById(; without this line, your view is actually not linked to the XML files of the fragments, but it shows ONLY the xml file of the main activity.

In addition to the line in the main activity java class, in the main activity XML file you need to change the tabs to fit your situation (e.g. add or remove TabItems). If you do not have tabs in the main activity XML, then possibly you did not choose the correct activity type when you created it in the first place (new activity - tabbed activity).

Please note that in the last 3 paragraphs I talk about the video! So when I say main activity XML, it is the main activity XML in the video, which in your situation is the MotherActivity XML file.

ASP.NET - How to write some html in the page? With Response.Write?

why don't you give LiteralControl a try?

 myLitCtrl.Text="<h2><p>Notify:</p> Alert</h2>";

Chmod recursively

You need read access, in addition to execute access, to list a directory. If you only have execute access, then you can find out the names of entries in the directory, but no other information (not even types, so you don't know which of the entries are subdirectories). This works for me:

find . -type d -exec chmod +rx {} \;

Why is the apt-get function not working in the terminal on Mac OS X v10.9 (Mavericks)?

Conda can also be used as package manager. It can be installed from Anaconda.

Alternatively, a free minimal installer is Miniconda.

What do I use on linux to make a python program executable

Just put this in the first line of your script :

#!/usr/bin/env python

Make the file executable with

chmod +x

Execute with


How to enter a series of numbers automatically in Excel

If you want to pick cell entries from a list then you have a couple of non-code based options

I would recommend The Data Validation approach where

  • creating a list of your 100 records in a single column,
  • provide a range name to this list,
  • then using Data Validation's List option

sample from Debra's site below, click on the first link above to access it.

Data Validation

Android scale animation on view

try this code to create Scale animation without using xml

ScaleAnimation animation = new ScaleAnimation(fromXscale, toXscale, fromYscale, toYscale, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);

Google Drive as FTP Server

With google-drive-ftp-adapter I have been able to access the My Drive area of Google Drive with the FileZilla FTP client. However, I have not been able to access the Shared with me area.

You can configure which Google account credentials it uses by changing the account property in the file from default to the desired Google account name. See the instructions at

What does the return keyword do in a void method in Java?

The Java language specification says you can have return with no expression if your method returns void.

This IP, site or mobile application is not authorized to use this API key

  1. Choose key
  2. API Restriction tab
  3. Choose API key
  4. Save
  5. Choose Application Restriction -> None
  6. Save

enter image description here

enter image description here

enter image description here

enter image description here

Checking host availability by using ping in bash scripts

I liked the idea of checking a list like:

for i in `cat Hostlist`
  ping -c1 -w2 $i | grep "PING" | awk '{print $2,$3}'

but that snippet doesn't care if a host is unreachable, so is not a great answer IMHO.

I ran with it and wrote

for i in `cat Hostlist`
  ping -c1 -w2 $i >/dev/null 2>&1 ; echo $i $?

And I can then handle each accordingly.

Most efficient way to check for DBNull and then assign to a variable?

I personally favour this syntax, which uses the explicit IsDbNull method exposed by IDataRecord, and caches the column index to avoid a duplicate string lookup.

Expanded for readability, it goes something like:

int columnIndex = row.GetOrdinal("Foo");
string foo; // the variable we're assigning based on the column value.
if (row.IsDBNull(columnIndex)) {
  foo = String.Empty; // or whatever
} else { 
  foo = row.GetString(columnIndex);

Rewritten to fit on a single line for compactness in DAL code - note that in this example we're assigning int bar = -1 if row["Bar"] is null.

int i; // can be reused for every field.
string foo  = (row.IsDBNull(i  = row.GetOrdinal("Foo")) ? null : row.GetString(i));
int bar = (row.IsDbNull(i = row.GetOrdinal("Bar")) ? -1 : row.GetInt32(i));

The inline assignment can be confusing if you don't know it's there, but it keeps the entire operation on one line, which I think enhances readability when you're populating properties from multiple columns in one block of code.

What's the best way of scraping data from a website?

You will definitely want to start with a good web scraping framework. Later on you may decide that they are too limiting and you can put together your own stack of libraries but without a lot of scraping experience your design will be much worse than pjscrape or scrapy.

Note: I use the terms crawling and scraping basically interchangeable here. This is a copy of my answer to your Quora question, it's pretty long.


Get very familiar with either Firebug or Chrome dev tools depending on your preferred browser. This will be absolutely necessary as you browse the site you are pulling data from and map out which urls contain the data you are looking for and what data formats make up the responses.

You will need a good working knowledge of HTTP as well as HTML and will probably want to find a decent piece of man in the middle proxy software. You will need to be able to inspect HTTP requests and responses and understand how the cookies and session information and query parameters are being passed around. Fiddler ( and Charles Proxy ( are popular tools. I use mitmproxy ( a lot as I'm more of a keyboard guy than a mouse guy.

Some kind of console/shell/REPL type environment where you can try out various pieces of code with instant feedback will be invaluable. Reverse engineering tasks like this are a lot of trial and error so you will want a workflow that makes this easy.


PHP is basically out, it's not well suited for this task and the library/framework support is poor in this area. Python (Scrapy is a great starting point) and Clojure/Clojurescript (incredibly powerful and productive but a big learning curve) are great languages for this problem. Since you would rather not learn a new language and you already know Javascript I would definitely suggest sticking with JS. I have not used pjscrape but it looks quite good from a quick read of their docs. It's well suited and implements an excellent solution to the problem I describe below.

A note on Regular expressions: DO NOT USE REGULAR EXPRESSIONS TO PARSE HTML. A lot of beginners do this because they are already familiar with regexes. It's a huge mistake, use xpath or css selectors to navigate html and only use regular expressions to extract data from actual text inside an html node. This might already be obvious to you, it becomes obvious quickly if you try it but a lot of people waste a lot of time going down this road for some reason. Don't be scared of xpath or css selectors, they are WAY easier to learn than regexes and they were designed to solve this exact problem.

Javascript-heavy sites

In the old days you just had to make an http request and parse the HTML reponse. Now you will almost certainly have to deal with sites that are a mix of standard HTML HTTP request/responses and asynchronous HTTP calls made by the javascript portion of the target site. This is where your proxy software and the network tab of firebug/devtools comes in very handy. The responses to these might be html or they might be json, in rare cases they will be xml or something else.

There are two approaches to this problem:

The low level approach:

You can figure out what ajax urls the site javascript is calling and what those responses look like and make those same requests yourself. So you might pull the html from and extract one piece of data and then have to pull the json response from to get the other piece of data. You'll need to be aware of passing the correct cookies or session parameters. It's very rare, but occasionally some required parameters for an ajax call will be the result of some crazy calculation done in the site's javascript, reverse engineering this can be annoying.

The embedded browser approach:

Why do you need to work out what data is in html and what data comes in from an ajax call? Managing all that session and cookie data? You don't have to when you browse a site, the browser and the site javascript do that. That's the whole point.

If you just load the page into a headless browser engine like phantomjs it will load the page, run the javascript and tell you when all the ajax calls have completed. You can inject your own javascript if necessary to trigger the appropriate clicks or whatever is necessary to trigger the site javascript to load the appropriate data.

You now have two options, get it to spit out the finished html and parse it or inject some javascript into the page that does your parsing and data formatting and spits the data out (probably in json format). You can freely mix these two options as well.

Which approach is best?

That depends, you will need to be familiar and comfortable with the low level approach for sure. The embedded browser approach works for anything, it will be much easier to implement and will make some of the trickiest problems in scraping disappear. It's also quite a complex piece of machinery that you will need to understand. It's not just HTTP requests and responses, it's requests, embedded browser rendering, site javascript, injected javascript, your own code and 2-way interaction with the embedded browser process.

The embedded browser is also much slower at scale because of the rendering overhead but that will almost certainly not matter unless you are scraping a lot of different domains. Your need to rate limit your requests will make the rendering time completely negligible in the case of a single domain.

Rate Limiting/Bot behaviour

You need to be very aware of this. You need to make requests to your target domains at a reasonable rate. You need to write a well behaved bot when crawling websites, and that means respecting robots.txt and not hammering the server with requests. Mistakes or negligence here is very unethical since this can be considered a denial of service attack. The acceptable rate varies depending on who you ask, 1req/s is the max that the Google crawler runs at but you are not Google and you probably aren't as welcome as Google. Keep it as slow as reasonable. I would suggest 2-5 seconds between each page request.

Identify your requests with a user agent string that identifies your bot and have a webpage for your bot explaining it's purpose. This url goes in the agent string.

You will be easy to block if the site wants to block you. A smart engineer on their end can easily identify bots and a few minutes of work on their end can cause weeks of work changing your scraping code on your end or just make it impossible. If the relationship is antagonistic then a smart engineer at the target site can completely stymie a genius engineer writing a crawler. Scraping code is inherently fragile and this is easily exploited. Something that would provoke this response is almost certainly unethical anyway, so write a well behaved bot and don't worry about this.


Not a unit/integration test person? Too bad. You will now have to become one. Sites change frequently and you will be changing your code frequently. This is a large part of the challenge.

There are a lot of moving parts involved in scraping a modern website, good test practices will help a lot. Many of the bugs you will encounter while writing this type of code will be the type that just return corrupted data silently. Without good tests to check for regressions you will find out that you've been saving useless corrupted data to your database for a while without noticing. This project will make you very familiar with data validation (find some good libraries to use) and testing. There are not many other problems that combine requiring comprehensive tests and being very difficult to test.

The second part of your tests involve caching and change detection. While writing your code you don't want to be hammering the server for the same page over and over again for no reason. While running your unit tests you want to know if your tests are failing because you broke your code or because the website has been redesigned. Run your unit tests against a cached copy of the urls involved. A caching proxy is very useful here but tricky to configure and use properly.

You also do want to know if the site has changed. If they redesigned the site and your crawler is broken your unit tests will still pass because they are running against a cached copy! You will need either another, smaller set of integration tests that are run infrequently against the live site or good logging and error detection in your crawling code that logs the exact issues, alerts you to the problem and stops crawling. Now you can update your cache, run your unit tests and see what you need to change.

Legal Issues

The law here can be slightly dangerous if you do stupid things. If the law gets involved you are dealing with people who regularly refer to wget and curl as "hacking tools". You don't want this.

The ethical reality of the situation is that there is no difference between using browser software to request a url and look at some data and using your own software to request a url and look at some data. Google is the largest scraping company in the world and they are loved for it. Identifying your bots name in the user agent and being open about the goals and intentions of your web crawler will help here as the law understands what Google is. If you are doing anything shady, like creating fake user accounts or accessing areas of the site that you shouldn't (either "blocked" by robots.txt or because of some kind of authorization exploit) then be aware that you are doing something unethical and the law's ignorance of technology will be extraordinarily dangerous here. It's a ridiculous situation but it's a real one.

It's literally possible to try and build a new search engine on the up and up as an upstanding citizen, make a mistake or have a bug in your software and be seen as a hacker. Not something you want considering the current political reality.

Who am I to write this giant wall of text anyway?

I've written a lot of web crawling related code in my life. I've been doing web related software development for more than a decade as a consultant, employee and startup founder. The early days were writing perl crawlers/scrapers and php websites. When we were embedding hidden iframes loading csv data into webpages to do ajax before Jesse James Garrett named it ajax, before XMLHTTPRequest was an idea. Before jQuery, before json. I'm in my mid-30's, that's apparently considered ancient for this business.

I've written large scale crawling/scraping systems twice, once for a large team at a media company (in Perl) and recently for a small team as the CTO of a search engine startup (in Python/Javascript). I currently work as a consultant, mostly coding in Clojure/Clojurescript (a wonderful expert language in general and has libraries that make crawler/scraper problems a delight)

I've written successful anti-crawling software systems as well. It's remarkably easy to write nigh-unscrapable sites if you want to or to identify and sabotage bots you don't like.

I like writing crawlers, scrapers and parsers more than any other type of software. It's challenging, fun and can be used to create amazing things.

JavaScript displaying a float to 2 decimal places

function round(value, decimals) { return Number(Math.round(value+'e'+decimals)+'e-'+decimals); }

round(1.005, 2); // return 1.01

round(1.004, 2); // return 1 instead of 1.00

The answer is following this link:

How can I do time/hours arithmetic in Google Spreadsheet?

In the case you want to format it within a formula (for example, if you are concatenating strings and values), the aforementioned format option of Google is not available, but you can use the TEXT formula:


Therefore, for the questioned example, with concatenation:

="The number of " & TEXT(B1,"HH") & " hour slots in " & TEXT(C1,"HH") _
& " is " & TEXT(C1/B1,"HH")


Using a remote repository with non-standard port

SSH based git access method can be specified in <repo_path>/.git/config using either a full URL or an SCP-like syntax, as specified in

URL style:

url = ssh://[user@]host.xz[:port]/path/to/repo.git/

SCP style:

url = [user@]host.xz:path/to/repo.git/

Notice that the SCP style does not allow a direct port change, relying instead on an ssh_config host definition in your ~/.ssh/config such as:

Host my_git_host
Port 24589
User not_a_root_user

Then you can test in a shell with:

ssh my_git_host

and alter your SCP-style URI in <repo_path>/.git/config as:

url = my_git_host:path/to/repo.git/

Ubuntu: OpenJDK 8 - Unable to locate package

After adding the JDK repo, before Installing you might want to run an update first so the repo can be added run apt update

an then continue with your installation sudo apt install adoptopenjdk-8-hotspot

How do you determine a processing time in Python?

If all you want is the time between two points in code (and it seems that's what you want) I have written tic() toc() functions ala Matlab's implementation. The basic use case is:


''' some code that runs for an interesting amount of time '''


# Elapsed time is: 32.42123 seconds

Super, incredibly easy to use, a sort of fire-and-forget kind of code. It's available on Github's Gist

How to include scripts located inside the node_modules folder?

Usually, you don't want to expose any of your internal paths for how your server is structured to the outside world. What you can is make a /scripts static route in your server that fetches its files from whatever directory they happen to reside in. So, if your files are in "./node_modules/bootstrap/dist/". Then, the script tag in your pages just looks like this:

<script src="/scripts/bootstrap.min.js"></script>

If you were using express with nodejs, a static route is as simple as this:

app.use('/scripts', express.static(__dirname + '/node_modules/bootstrap/dist/'));

Then, any browser requests from /scripts/xxx.js will automatically be fetched from your dist directory at __dirname + /node_modules/bootstrap/dist/xxx.js.

Note: Newer versions of NPM put more things at the top level, not nested so deep so if you are using a newer version of NPM, then the path names will be different than indicated in the OP's question and in the current answer. But, the concept is still the same. You find out where the files are physically located on your server drive and you make an app.use() with express.static() to make a pseudo-path to those files so you aren't exposing the actual server file system organization to the client.

If you don't want to make a static route like this, then you're probably better off just copying the public scripts to a path that your web server does treat as /scripts or whatever top level designation you want to use. Usually, you can make this copying part of your build/deployment process.

If you want to make just one particular file public in a directory and not everything found in that directory with it, then you can manually create individual routes for each file rather than use express.static() such as:

<script src="/bootstrap.min.js"></script>

And the code to create a route for that

app.get('/bootstrap.min.js', function(req, res) {
    res.sendFile(__dirname + '/node_modules/bootstrap/dist/bootstrap.min.js');

Or, if you want to still delineate routes for scripts with /scripts, you could do this:

<script src="/scripts/bootstrap.min.js"></script>

And the code to create a route for that

app.get('/scripts/bootstrap.min.js', function(req, res) {
    res.sendFile(__dirname + '/node_modules/bootstrap/dist/bootstrap.min.js');

How do I run Google Chrome as root?

Chrome can run as root (remember to use gksu when doing so) so long as you provide it with a profile directory.

Rather than type in the profile directory every time you want to run it, create a new bash file (I'd name it something like

google-chrome --user-data-dir="/root/chrome-profile/"

Rember to call that script with root privelages!

$ gksu /root/

Excel cell value as string won't store as string

Use Range("A1").Text instead of .Value

post comment edit:
Because the .Text property of Range object returns what is literally visible in the spreadsheet, so if you cell displays for example i100l:25he*_92 then <- Text will return exactly what it in the cell including any formatting.
The .Value and .Value2 properties return what's stored in the cell under the hood excluding formatting. Specially .Value2 for date types, it will return the decimal representation.

If you want to dig deeper into the meaning and performance, I just found this article which seems like a good guide

another edit
Here you go @Santosh
type in (MANUALLY) the values from the DEFAULT (col A) to other columns
Do not format column A at all
Format column B as Text
Format column C as Date[dd/mm/yyyy]
Format column D as Percentage
Dont Format column A, Format B as TEXT, C as Date, D as Percentage
paste this code in a module

Sub main()

    Dim ws As Worksheet, i&, j&
    Set ws = Sheets(1)
    For i = 3 To 7
        For j = 1 To 4
            Debug.Print _
                    "row " & i & vbTab & vbTab & _
                    Cells(i, j).Text & vbTab & _
                    Cells(i, j).Value & vbTab & _
                    Cells(i, j).Value2
        Next j
    Next i
End Sub

and Analyse the output! Its really easy and there isn't much more i can do to help :)

            .TEXT              .VALUE             .VALUE2
row 3       hello             hello               hello
row 3       hello             hello               hello
row 3       hello             hello               hello
row 3       hello             hello               hello
row 4       1                 1                   1
row 4       1                 1                   1
row 4       01/01/1900        31/12/1899          1
row 4       1.00%             0.01                0.01
row 5       helo1$$           helo1$$             helo1$$
row 5       helo1$$           helo1$$             helo1$$
row 5       helo1$$           helo1$$             helo1$$
row 5       helo1$$           helo1$$             helo1$$
row 6       63                63                  63
row 6       =7*9              =7*9                =7*9
row 6       03/03/1900        03/03/1900          63
row 6       6300.00%          63                  63
row 7       29/05/2013        29/05/2013          41423
row 7       29/05/2013        29/05/2013          29/05/2013
row 7       29/05/2013        29/05/2013          41423
row 7       29/05/2013%       29/05/2013%         29/05/2013%

What is the role of "Flatten" in Keras?

It is rule of thumb that the first layer in your network should be the same shape as your data. For example our data is 28x28 images, and 28 layers of 28 neurons would be infeasible, so it makes more sense to 'flatten' that 28,28 into a 784x1. Instead of wriitng all the code to handle that ourselves, we add the Flatten() layer at the begining, and when the arrays are loaded into the model later, they'll automatically be flattened for us.

How can I ssh directly to a particular directory?

I know this has been answered ages ago but I found the question while trying to incorporate an ssh login in a bash script and once logged in run a few commands and log back out and continue with the bash script. The simplest way I found which hasnt been mentioned elsewhere because it is so trivial is to do this.


sshpass -p "password" ssh user@server 'cd /path/to/dir;somecommand;someothercommand;exit;'

jQuery Validate Required Select

how to validate the select "qualifica" it has 3 choose


        rules: {
            fullname: 'required',
            ragionesociale: 'required',
            partitaiva: 'required',
            recapitotelefonico: 'required',
            qualifica: 'required',
            email: {
                required: true,
                email: true
        submitHandler: function(form) {

            var fullname = $('#fullname').val(),
                            ragionesociale = $('#ragionesociale').val(),
                            partitaiva = $('#partitaiva').val(),
                            email = $('#email').val(),
                            recapitotelefonico = $('#recapitotelefonico').val(),
                            qualifica = $('#qualifica').val(),
                            dataString = 'fullname=' + fullname + '&ragionesociale=' + ragionesociale + '&partitaiva=' + partitaiva + '&email=' + email + '&recapitotelefonico=' + recapitotelefonico + '&qualifica=' + qualifica;

                type: "POST",
                url: "util/sender.php",
                data: dataString,
                success: function() {


            return false;


jQuery - disable selected options

pls try this,

$('#select_id option[value="'+value+'"]').attr("disabled", true);

Remove xticks in a matplotlib plot?

Not exactly what the OP was asking for, but a simple way to disable all axes lines, ticks and labels is to simply call:


How do I install TensorFlow's tensorboard?

It is better not to mix up the virtual environments or perform installation on the root directory. Steps I took for hassle free installation are as below. I used conda for installing all my dependencies instead of pip. I'm answering with extra details, because when I tried to install tensor board and tensor flow on my root env, it messed up.

  • Create a virtual env

    conda create --name my_env python=3.6

  • Activate virtual environment

    source activate my_env

  • Install basic required modules

    conda install pandas

    conda install tensorflow

  • Install tensor board

    conda install -c condo-forge tensor board

Hope that helps

What are "res" and "req" parameters in Express functions?

req is an object containing information about the HTTP request that raised the event. In response to req, you use res to send back the desired HTTP response.

Those parameters can be named anything. You could change that code to this if it's more clear:

app.get('/user/:id', function(request, response){
  response.send('user ' +;


Say you have this method:

app.get('/people.json', function(request, response) { });

The request will be an object with properties like these (just to name a few):

  • request.url, which will be "/people.json" when this particular action is triggered
  • request.method, which will be "GET" in this case, hence the app.get() call.
  • An array of HTTP headers in request.headers, containing items like request.headers.accept, which you can use to determine what kind of browser made the request, what sort of responses it can handle, whether or not it's able to understand HTTP compression, etc.
  • An array of query string parameters if there were any, in request.query (e.g. /people.json?foo=bar would result in containing the string "bar").

To respond to that request, you use the response object to build your response. To expand on the people.json example:

app.get('/people.json', function(request, response) {
  // We want to set the content-type header so that the browser understands
  //  the content of the response.

  // Normally, the data is fetched from a database, but we can cheat:
  var people = [
    { name: 'Dave', location: 'Atlanta' },
    { name: 'Santa Claus', location: 'North Pole' },
    { name: 'Man in the Moon', location: 'The Moon' }

  // Since the request is for a JSON representation of the people, we
  //  should JSON serialize them. The built-in JSON.stringify() function
  //  does that.
  var peopleJSON = JSON.stringify(people);

  // Now, we can use the response object's send method to push that string
  //  of people JSON back to the browser in response to this request:

How do I log errors and warnings into a file?

In addition, you need the "AllowOverride Options" directive for this to work. (Apache 2.2.15)

CSS transition with visibility not working

Visibility is animatable. Check this blog post about it:

You can see it here too:

Let's say you have a menu that you want to fade-in and fade-out on mouse hover. If you use opacity:0 only, your transparent menu will still be there and it will animate when you hover the invisible area. But if you add visibility:hidden, you can eliminate this problem:

div {_x000D_
.menu {_x000D_
    transition:visibility 0.3s linear,opacity 0.3s linear;_x000D_
div:hover > .menu {_x000D_
  <a href="#">Open Menu</a>_x000D_
  <ul class="menu">_x000D_
    <li><a href="#">Item</a></li>_x000D_
    <li><a href="#">Item</a></li>_x000D_
    <li><a href="#">Item</a></li>_x000D_

In C, how should I read a text file and print all strings

Two approaches leap to mind.

First, don't use scanf. Use fgets() which takes a parameter to specify the buffer size, and which leaves any newline characters intact. A simple loop over the file that prints the buffer content should naturally copy the file intact.

Second, use fread() or the common C idiom with fgetc(). These would process the file in fixed-size chunks or a single character at a time.

If you must process the file over white-space delimited strings, then use either fgets or fread to read the file, and something like strtok to split the buffer at whitespace. Don't forget to handle the transition from one buffer to the next, since your target strings are likely to span the buffer boundary.

If there is an external requirement to use scanf to do the reading, then limit the length of the string it might read with a precision field in the format specifier. In your case with a 999 byte buffer, then say scanf("%998s", str); which will write at most 998 characters to the buffer leaving room for the nul terminator. If single strings longer than your buffer are allowed, then you would have to process them in two pieces. If not, you have an opportunity to tell the user about an error politely without creating a buffer overflow security hole.

Regardless, always validate the return values and think about how to handle bad, malicious, or just malformed input.

Custom format for time command

To use the Bash builtin time rather than /bin/time you can set this variable:


which will output the real time that looks like this:




The number specifies the precision and can range from 0 to 3 (the default).

You can use:


to get output that looks like:


The l (ell) gives a long format.

Socket transport "ssl" in PHP not enabled

In XAMPP Version 1.7.4 server does not have extension=php_openssl.dll line in php ini file. We have to add extension=php_openssl.dll in php.ini file