Programs & Examples On #Dft

Discrete Fourier transform (DFT) is a specific kind of discrete transform, used in Fourier analysis.

only integers, slices (`:`), ellipsis (`...`), numpy.newaxis (`None`) and integer or boolean arrays are valid indices

I believe your problem is this: in your while loop, n is divided by 2, but never cast as an integer again, so it becomes a float at some point. It is then added onto y, which is then a float too, and that gives you the warning.

Input type number "only numeric value" validation

The easiest way would be to use a library like this one and specifically you want noStrings to be true

    export class CustomValidator{   // Number only validation   
      static numeric(control: AbstractControl) {
        let val = control.value;

        const hasError = validate({val: val}, {val: {numericality: {noStrings: true}}});

        if (hasError) return null;

        return val;   

How to add external JS scripts to VueJS Components

You can load the script you need with a promise based solution:

export default {
  data () {
    return { is_script_loading: false }
  created () {
    // If another component is already loading the script
    this.$root.$on('loading_script', e => { this.is_script_loading = true })
  methods: {
    load_script () {
      let self = this
      return new Promise((resolve, reject) => {

        // if script is already loading via another component
        if ( self.is_script_loading ){
          // Resolve when the other component has loaded the script
          this.$root.$on('script_loaded', resolve)

        let script = document.createElement('script')
        script.setAttribute('src', '')
        script.async = true

        script.onload = () => {
          /* emit to global event bus to inform other components
           * we are already loading the script */



    async use_script () {
      try {
        await this.load_script()
        // .. do what you want after script has loaded
      } catch (err) { console.log(err) }


Please note that this.$root is a little hacky and you should use a vuex or eventHub solution for the global events instead.

You would make the above into a component and use it wherever needed, it will only load the script when used.

NOTE: This is a Vue 2.x based solution. Vue 3 has stopped supporting $on.

Open Url in default web browser

Try this:

import React, { useCallback } from "react";
import { Linking } from "react-native";
OpenWEB = () => {

const App = () => {
  return <View onPress={() => OpenWeb}>OPEN YOUR WEB</View>;

Hope this will solve your problem.

What Java ORM do you prefer, and why?

Many ORM's are great, you need to know why you want to add abstraction on top of JDBC. I can recommend to you (disclaimer: I'm the creator of jOOQ, so this answer is biased). jOOQ embraces the following paradigm:

  • SQL is a good thing. Many things can be expressed quite nicely in SQL. There is no need for complete abstraction of SQL.
  • The relational data model is a good thing. It has proven the best data model for the last 40 years. There is no need for XML databases or truly object oriented data models. Instead, your company runs several instances of Oracle, MySQL, MSSQL, DB2 or any other RDBMS.
  • SQL has a structure and syntax. It should not be expressed using "low-level" String concatenation in JDBC - or "high-level" String concatenation in HQL - both of which are prone to hold syntax errors.
  • Variable binding tends to be very complex when dealing with major queries. THAT is something that should be abstracted.
  • POJO's are great when writing Java code manipulating database data.
  • POJO's are a pain to write and maintain manually. Code generation is the way to go. You will have compile-safe queries including datatype-safety.
  • The database comes first. While the application on top of your database may change over time, the database itself is probably going to last longer.
  • Yes, you do have stored procedures and user defined types (UDT's) in your legacy database. Your database-tool should support that.

There are many other good ORM's. Especially Hibernate or iBATIS have a great community. But if you're looking for an intuitive, simple one, I'll say give jOOQ a try. You'll love it! :-)

Check out this example SQL:

  // Select authors with books that are sold out
                   FROM T_BOOK
                  WHERE T_BOOK.STATUS = 'SOLD OUT'
                    AND T_BOOK.AUTHOR_ID = a.ID);

And how it can be expressed in jOOQ:

  // Alias the author table
  TAuthor a ="a");

  // Use the aliased table in the select statement

Create a batch file to run an .exe with an additional parameter

You can use

start "" "%USERPROFILE%\Desktop\BGInfo\bginfo.exe" "%USERPROFILE%\Desktop\BGInfo\dc_bginfo.bgi"


start "" /D "%USERPROFILE%\Desktop\BGInfo" bginfo.exe dc_bginfo.bgi


"%USERPROFILE%\Desktop\BGInfo\bginfo.exe" "%USERPROFILE%\Desktop\BGInfo\dc_bginfo.bgi"


cd /D "%USERPROFILE%\Desktop\BGInfo"
bginfo.exe dc_bginfo.bgi

Help on commands start and cd is output by executing in a command prompt window help start or start /? and help cd or cd /?.

But I do not understand why you need a batch file at all for starting the application with the additional parameter. Create a shortcut (*.lnk) on your desktop for this application. Then right click on the shortcut, left click on Properties and append after a space character "%USERPROFILE%\Desktop\BGInfo\dc_bginfo.bgi" as parameter.

'invalid value encountered in double_scalars' warning, possibly numpy

Sometimes NaNs or null values in data will generate this error with Numpy. If you are ingesting data from say, a CSV file or something like that, and then operating on the data using numpy arrays, the problem could have originated with your data ingest. You could try feeding your code a small set of data with known values, and see if you get the same result.

Extracting columns from text file with different delimiters in Linux

If the command should work with both tabs and spaces as the delimiter I would use awk:

awk '{print $100,$101,$102,$103,$104,$105}' myfile > outfile

As long as you just need to specify 5 fields it is imo ok to just type them, for longer ranges you can use a for loop:

awk '{for(i=100;i<=105;i++)print $i}' myfile > outfile

If you want to use cut, you need to use the -f option:

cut -f100-105 myfile > outfile

If the field delimiter is different from TAB you need to specify it using -d:

cut -d' ' -f100-105 myfile > outfile

Check the man page for more info on the cut command.

How to set shadows in React Native for android?

Also i'd like to add that if one's trying to apply shadow in a TouchableHighlight Component in which child has borderRadius, the parent element (TouchableHighlight) also need the radius set in order to elevation prop work on Android.

How to find and return a duplicate value in array

Simply find the first instance where the index of the object (counting from the left) does not equal the index of the object (counting from the right).

arr.detect {|e| arr.rindex(e) != arr.index(e) }

If there are no duplicates, the return value will be nil.

I believe this is the fastest solution posted in the thread so far, as well, since it doesn't rely on the creation of additional objects, and #index and #rindex are implemented in C. The big-O runtime is N^2 and thus slower than Sergio's, but the wall time could be much faster due to the the fact that the "slow" parts run in C.

How to download a file via FTP with Python ftplib

This is a Python code that is working fine for me. Comments are in Spanish but the app is easy to understand

# coding=utf-8

from ftplib import FTP                                                                      # Importamos la libreria ftplib desde FTP

import sys

def imprimirMensaje():                                                                      # Definimos la funcion para Imprimir el mensaje de bienvenida
    print "------------------------------------------------------"
    print "--               COMMAND LINE EXAMPLE               --"
    print "------------------------------------------------------"
    print ""
    print ">>>             Cliente FTP  en Python                "
    print ""
    print ">>> python <appname>.py <host> <port> <user> <pass>   "
    print "------------------------------------------------------"

def f(s):                                                                                   # Funcion para imprimir por pantalla los datos 
    print s

def download(j):                                                                            # Funcion para descargarnos el fichero que indiquemos según numero    
    print "Descargando=>",files[j]      
    fhandle = open(files[j], 'wb')
    ftp.retrbinary('RETR ' + files[j], fhandle.write)                                       # Imprimimos por pantalla lo que estamos descargando        #fhandle.close()

ip          = sys.argv[1]                                                                   # Recogemos la IP       desde la linea de comandos sys.argv[1] 
puerto      = sys.argv[2]                                                                   # Recogemos el PUERTO   desde la linea de comandos sys.argv[2]
usuario     = sys.argv[3]                                                                   # Recogemos el USUARIO  desde la linea de comandos sys.argv[3]
password    = sys.argv[4]                                                                   # Recogemos el PASSWORD desde la linea de comandos sys.argv[4]

ftp = FTP(ip)                                                                               # Creamos un objeto realizando una instancia de FTP pasandole la IP
ftp.login(usuario,password)                                                                 # Asignamos al objeto ftp el usuario y la contraseña

files = ftp.nlst()                                                                          # Ponemos en una lista los directorios obtenidos del FTP

for i,v in enumerate(files,1):                                                              # Imprimimos por pantalla el listado de directorios enumerados
    print i,"->",v

print ""
i = int(raw_input("Pon un Nº para descargar el archivo or pulsa 0 para descargarlos\n"))    # Introducimos algun numero para descargar el fichero que queramos. Lo convertimos en integer

if i==0:                                                                                    # Si elegimos el valor 0 nos decargamos todos los ficheros del directorio                                                                               
    for j in range(len(files)):                                                             # Hacemos un for para la lista files y
        download(j)                                                                         # llamamos a la funcion download para descargar los ficheros
if i>0 and i<=len(files):                                                                   # Si elegimos unicamente un numero para descargarnos el elemento nos lo descargamos. Comprobamos que sea mayor de 0 y menor que la longitud de files 
    download(i-1)                                                                           # Nos descargamos i-1 por el tema que que los arrays empiezan por 0 

Laravel PDOException SQLSTATE[HY000] [1049] Unknown database 'forge'

Sounds like you have an environment-specific config file somewhere that overrides the default database settings. Possibly app/config/local/database.php.

Function vs. Stored Procedure in SQL Server

              STORE PROCEDURE                 FUNCTION (USER DEFINED FUNCTION)    
 * Procedure can return 0, single or   | * Function can return only single value   
   multiple values.                    |
 * Procedure can have input, output    | * Function  can have only input 
   parameters.                         |   parameters.         
 * Procedure cannot be called from     | * Functions can be called from 
   function.                           |   procedure.
 * Procedure allows select as well as  | * Function allows only select statement 
   DML statement in it.                |   in it.
 * Exception can be handled by         | * Try-catch block cannot be used in a 
   try-catch block in a procedure.     |   function.
 * We can go for transaction management| * We can not go for transaction 
   in procedure.                       |   management in function.
 * Procedure cannot be utilized in a   | * Function can be embedded in a select 
   select statement                    |   statement.
 * Procedure can affect the state      | * Function can not affect the state 
   of database means it can perform    |   of database means it can not    
   CRUD operation on database.         |   perform CRUD operation on 
                                       |   database. 
 * Procedure can use temporary tables. | * Function can not use 
                                       |   temporary tables. 
 * Procedure can alter the server      | * Function can not alter the  
   environment parameters.             |   environment parameters.
 * Procedure can use when we want      | * Function can use when we want
   instead is to group a possibly-     |   to compute and return a value
   complex set of SQL statements.      |   for use in other SQL 
                                       |   statements.

Writing string to a file on a new line every time

This is the solution that I came up with trying to solve this problem for myself in order to systematically produce \n's as separators. It writes using a list of strings where each string is one line of the file, however it seems that it may work for you as well. (Python 3.+)

#Takes a list of strings and prints it to a file.
def writeFile(file, strList):
    line = 0
    lines = []
    while line < len(strList):
        lines.append(cheekyNew(line) + strList[line])
        line += 1
    file = open(file, "w")

#Returns "\n" if the int entered isn't zero, otherwise "".
def cheekyNew(line):
    if line != 0:
        return "\n"
    return ""

Laravel use same form for create and edit

Simple and clean :)


public function create() {
    $user = new User();

    return View::make('user.edit', compact('user'));

public function edit($id) {
    $user = User::find($id);

    return View::make('user.edit', compact('user'));


{{ Form::model($user, ['url' => ['/user', $user->id]]) }}
   {{ Form::text('name') }}
{{ Form::close() }}

Angular 4 img src is not found

in your component assign a variable like,

export class AppComponent {
  netImage:any = "../assets/network.jpg";
  title = 'app';

use this netImage in your src to get the image, as given below,

<figure class="figure">
  <img [src]="netImage" class="figure-img img-fluid rounded" alt="A generic square placeholder image with rounded corners in a figure.">
  <figcaption class="figure-caption">A caption for the above image.</figcaption>

How to programmatically set the layout_align_parent_right attribute of a Button in Relative Layout?

You can access any LayoutParams from code using View.getLayoutParams. You just have to be very aware of what LayoutParams your accessing. This is normally achieved by checking the containing ViewGroup if it has a LayoutParams inner child then that's the one you should use. In your case it's RelativeLayout.LayoutParams. You'll be using RelativeLayout.LayoutParams#addRule(int verb) and RelativeLayout.LayoutParams#addRule(int verb, int anchor)

You can get to it via code:

RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams)button.getLayoutParams();

button.setLayoutParams(params); //causes layout update

What's the difference between <mvc:annotation-driven /> and <context:annotation-config /> in servlet?

<context:annotation-config> declares support for general annotations such as @Required, @Autowired, @PostConstruct, and so on.

<mvc:annotation-driven /> declares explicit support for annotation-driven MVC controllers (i.e. @RequestMapping, @Controller, although support for those is the default behaviour), as well as adding support for declarative validation via @Valid and message body marshalling with @RequestBody/ResponseBody.

curl_exec() always returns false

In my case I need to set VERIFYHOST and VERIFYPEER to false, like this:


before the call to curl_exec($ch).

Because i am working between two development environments with self-assigned certificates. With valid certificates there is no need to set VERIFYHOST and VERIFYPEER to false because the curl_exec($ch) method will work and return the response you expect.

Python unexpected EOF while parsing

Check if all the parameters of functions are defined before they are called. I faced this problem while practicing Kaggle.

jQuery Validation plugin: validate check box

You can validate group checkbox and radio button without extra js code, see below example.

Your JS should be look like:


You can play with HTML tag and attributes: eg. group checkbox [minlength=2 and maxlength=4]

<fieldset class="col-md-12">
  <div class="form-row">
    <div class="col-12 col-md-12 form-group">
        <label class="checkbox-inline">
          <input type="checkbox" name="daysgroup[]" value="1" required="required" data-msg-required="This value is required." minlength="2" maxlength="4" data-msg-maxlength="Max should be 4">Monday
        <label class="checkbox-inline">
          <input type="checkbox" name="daysgroup[]" value="2">Tuesday
        <label class="checkbox-inline">
          <input type="checkbox" name="daysgroup[]" value="3">Wednesday
        <label class="checkbox-inline">
          <input type="checkbox" name="daysgroup[]" value="4">Thursday
        <label class="checkbox-inline">
          <input type="checkbox" name="daysgroup[]" value="5">Friday
        <label class="checkbox-inline">
          <input type="checkbox" name="daysgroup[]" value="6">Saturday
        <label class="checkbox-inline">
          <input type="checkbox" name="daysgroup[]" value="7">Sunday
        <label for="daysgroup[]" class="error">Your error message will be display here.</label>

You can see here first or any one input should have required, minlength="2" and maxlength="4" attributes. minlength/maxlength as per your requirement.

eg. group radio button:

<fieldset class="col-md-12">
  <div class="form-row">
    <div class="col-12 col-md-12 form-group">
        <label class="form-check-inline">
          <input type="radio" name="gendergroup[]" value="m" required="required" data-msg-required="This value is required.">man
        <label class="form-check-inline">
          <input type="radio" name="gendergroup[]" value="w">woman
        <label class="form-check-inline">
          <input type="radio" name="gendergroup[]" value="o">other
        <label for="gendergroup[]" class="error">Your error message will be display here.</label>

You can check working example here.

  • jQuery v3.3.x
  • jQuery Validation Plugin - v1.17.0

Android: Getting "Manifest merger failed" error after updating to a new version of gradle

Put this at the end of your app module build.gradle:

configurations.all {
    resolutionStrategy.eachDependency { DependencyResolveDetails details ->
        def requested = details.requested
        if ( == '') {
            if (!"multidex")) {
                details.useVersion '25.3.0'

Credit to Eugen Pechanec

Getting Raw XML From SOAPMessage in Java

for just debugging purpose, use one line code -


Python: converting a list of dictionaries to json

use json library

import json

by the way, you might consider changing variable list to another name, list is the builtin function for a list creation, you may get some unexpected behaviours or some buggy code if you don't change the variable name.

Rename a file in C#

public static class ImageRename
    public static void ApplyChanges(string fileUrl,
                                    string temporaryImageName,
                                    string permanentImageName)
        var currentFileName = Path.Combine(fileUrl,

        if (!File.Exists(currentFileName))
            throw new FileNotFoundException();

        var extention = Path.GetExtension(temporaryImageName);
        var newFileName = Path.Combine(fileUrl,

        if (File.Exists(newFileName))

        File.Move(currentFileName, newFileName);

Using Python Requests: Sessions, Cookies, and POST

I don't know how stubhub's api works, but generally it should look like this:

s = requests.Session()
data = {"login":"my_login", "password":"my_password"}
url = ""
r =, data=data)

Now your session contains cookies provided by login form. To access cookies of this session simply use


Any further actions like another requests will have this cookie

How to order a data frame by one descending and one ascending column?

    #supposing you want to arrange column 'c' in descending order and 'd' in ascending order. name of data frame is df
    ## first doing descending
    ## then the ascending order of col 'd;
    df <-arrange(df,d)

Check if my SSL Certificate is SHA1 or SHA2

I had to modify this slightly to be used on a Windows System. Here's the one-liner version for a windows box.

openssl.exe s_client -connect > CertInfo.txt && openssl x509 -text -in CertInfo.txt | find "Signature Algorithm" && del CertInfo.txt /F

Tested on Server 2012 R2 using

How to set index.html as root file in Nginx?

According to the documentation Checks the existence of files in the specified order and uses the first found file for request processing; the processing is performed in the current context. The path to a file is constructed from the file parameter according to the root and alias directives. It is possible to check directory’s existence by specifying a slash at the end of a name, e.g. “$uri/”. If none of the files were found, an internal redirect to the uri specified in the last parameter is made. Important

an internal redirect to the uri specified in the last parameter is made.

So in last parameter you should add your page or code if first two parameters returns false.

location / {
  try_files $uri $uri/index.html index.html;

Yes or No confirm box using jQuery

Try This... It's very simple just use confirm dialog box for alert with YES|NO.

if(confirm("Do you want to upgrade?")){ Your code }

How to add http:// if it doesn't exist in the URL

At the time of writing, none of the answers used a built-in function for this:

function addScheme($url, $scheme = 'http://')
  return parse_url($url, PHP_URL_SCHEME) === null ?
    $scheme . $url : $url;

echo addScheme(''); // ""
echo addScheme(''); // ""

See also: parse_url()

Referencing another schema in Mongoose

It sounds like the populate method is what your looking for. First make small change to your post schema:

var postSchema = new Schema({
    name: String,
    postedBy: {type: mongoose.Schema.Types.ObjectId, ref: 'User'},
    dateCreated: Date,
    comments: [{body:"string", by: mongoose.Schema.Types.ObjectId}],

Then make your model:

var Post = mongoose.model('Post', postSchema);

Then, when you make your query, you can populate references like this:

Post.findOne({_id: 123})
.exec(function(err, post) {
    // do stuff with post

How to copy selected files from Android with adb pull

Pull multiple files using regex:



for file in $(adb shell ls $DEVICE_DIR | grep $EXTENSION'$')
    file=$(echo -e $file | tr -d "\r\n"); # EOL fix
    adb pull $DEVICE_DIR/$file $HOST_DIR/$file;

Run it:

Make it executable: chmod +x

Run it: ./


  • as is, won't work when filenames have spaces
  • includes a fix for end-of-line (EOL) on Android, which is a "\r\n"

java.lang.UnsupportedClassVersionError: Unsupported major.minor version 51.0 (unable to load class frontend.listener.StartupListener)

What is your output when you do java -version? This will tell you what version the running JVM is.

The Unsupported major.minor version 51.0 error could mean:

  • Your server is running a lower Java version then the one used to compile your Servlet and vice versa

Either way, uninstall all JVM runtimes including JDK and download latest and re-install. That should fix any Unsupported major.minor error as you will have the lastest JRE and JDK (Maybe even newer then the one used to compile the Servlet)

See: (7 Update 25 )

and here: (Java Platform (JDK) 7u25)

for the latest version of the JRE and JDK respectively.


Most likely your code was written in Java7 however maybe it was done using Java7update4 and your system is running Java7update3. Thus they both are effectively the same major version but the minor versions differ. Only the larger minor version is backward compatible with the lower minor version.

Edit 2 : If you have more than one jdk installed on your pc. you should check that Apache Tomcat is using the same one (jre) you are compiling your programs with. If you installed a new jdk after installing apache it normally won't select the new version.

Cannot implicitly convert type 'System.Linq.IQueryable' to 'System.Collections.Generic.IList'

To convert IQuerable or IEnumerable to a list, you can do one of the following:

IQueryable<object> q = ...;
List<object> l = q.ToList();


IQueryable<object> q = ...;
List<object> l = new List<object>(q);

Get class name of object as string in Swift

I suggest such an approach (very Swifty):

// Swift 3
func typeName(_ some: Any) -> String {
    return (some is Any.Type) ? "\(some)" : "\(type(of: some))"

// Swift 2
func typeName(some: Any) -> String {
    return (some is Any.Type) ? "\(some)" : "\(some.dynamicType)"

It doesn't use neither introspection nor manual demangling (no magic!).

Here is a demo:

// Swift 3

import class Foundation.NSObject

func typeName(_ some: Any) -> String {
    return (some is Any.Type) ? "\(some)" : "\(type(of: some))"

class GenericClass<T> {
    var x: T? = nil

protocol Proto1 {
    func f(x: Int) -> Int

class Class1: NSObject, Proto1 {
    func f(x: Int) -> Int {
        return x

struct Struct1 {
    var x: Int

enum Enum1 {
    case X

print(typeName(GenericClass<Int>.self)) // GenericClass<Int>
print(typeName(GenericClass<Int>()))  // GenericClass<Int>

print(typeName(Proto1.self)) // Proto1

print(typeName(Class1.self))   // Class1
print(typeName(Class1())) // Class1
print(typeName(Class1().f)) // (Int) -> Int

print(typeName(Struct1.self)) // Struct1
print(typeName(Struct1(x: 1))) // Struct1
print(typeName(Enum1.self)) // Enum1
print(typeName(Enum1.X)) // Enum1

How does the stack work in assembly language?

(I've made a gist of all the code in this answer in case you want to play with it)

I have only ever did most basic things in asm during my CS101 course back in 2003. And I had never really "got it" how asm and stack work until I've realized that it's all basicaly like programming in C or C++ ... but without local variables, parameters and functions. Probably doesn't sound easy yet :) Let me show you (for x86 asm with Intel syntax).

1. What is the stack

Stack is usually a contiguous chunk of memory allocated for every thread before they start. You can store there whatever you want. In C++ terms (code snippet #1):

const int STACK_CAPACITY = 1000;
thread_local int stack[STACK_CAPACITY];

2. Stack's top and bottom

In principle, you could store values in random cells of stack array (snippet #2.1):

stack[333] = 123;
stack[517] = 456;
stack[555] = stack[333] + stack[517];

But imagine how hard would it be to remember which cells of stack are already in use and wich ones are "free". That's why we store new values on the stack next to each other.

One weird thing about (x86) asm's stack is that you add things there starting with the last index and move to lower indexes: stack[999], then stack[998] and so on (snippet #2.2):

stack[999] = 123;
stack[998] = 456;
stack[997] = stack[999] + stack[998];

And still (caution, you're gonna be confused now) the "official" name for stack[999] is bottom of the stack.
The last used cell (stack[997] in the example above) is called top of the stack (see Where the top of the stack is on x86).

3. Stack pointer (SP)

For the purpose of this discussion let's assume CPU registers are represented as global variables (see General-Purpose Registers).

int AX, BX, SP, BP, ...;
int main(){...}

There is special CPU register (SP) that tracks the top of the stack. SP is a pointer (holds a memory address like 0xAAAABBCC). But for the purposes of this post I'll use it as an array index (0, 1, 2, ...).

When a thread starts, SP == STACK_CAPACITY and then the program and OS modify it as needed. The rule is you can't write to stack cells beyond stack's top and any index less then SP is invalid and unsafe (because of system interrupts), so you first decrement SP and then write a value to the newly allocated cell.

When you want to push several values in the stack in a row, you can reserve space for all of them upfront (snippet #3):

SP -= 3;
stack[999] = 12;
stack[998] = 34;
stack[997] = stack[999] + stack[998];

Note. Now you can see why allocation on the stack is so fast - it's just a single register decrement.

4. Local variables

Let's take a look at this simplistic function (snippet #4.1):

int triple(int a) {
    int result = a * 3;
    return result;

and rewrite it without using of local variable (snippet #4.2):

int triple_noLocals(int a) {
    SP -= 1; // move pointer to unused cell, where we can store what we need
    stack[SP] = a * 3;
    return stack[SP];

and see how it is being called (snippet #4.3):

// SP == 1000
someVar = triple_noLocals(11);
// now SP == 999, but we don't need the value at stack[999] anymore
// and we will move the stack index back, so we can reuse this cell later
SP += 1; // SP == 1000 again

5. Push / pop

Addition of a new element on the top of the stack is such a frequent operation, that CPUs have a special instruction for that, push. We'll implent it like this (snippet 5.1):

void push(int value) {
    stack[SP] = value;

Likewise, taking the top element of the stack (snippet 5.2):

void pop(int& result) {
    result = stack[SP];
    ++SP; // note that `pop` decreases stack's size

Common usage pattern for push/pop is temporarily saving some value. Say, we have something useful in variable myVar and for some reason we need to do calculations which will overwrite it (snippet 5.3):

int myVar = ...;
push(myVar); // SP == 999
myVar += 10;
... // do something with new value in myVar
pop(myVar); // restore original value, SP == 1000

6. Function parameters

Now let's pass parameters using stack (snippet #6):

int triple_noL_noParams() { // `a` is at index 999, SP == 999
    SP -= 1; // SP == 998, stack[SP + 1] == a
    stack[SP] = stack[SP + 1] * 3;
    return stack[SP];

int main(){
    push(11); // SP == 999
    assert(triple(11) == triple_noL_noParams());
    SP += 2; // cleanup 1 local and 1 parameter

7. return statement

Let's return value in AX register (snippet #7):

void triple_noL_noP_noReturn() { // `a` at 998, SP == 998
    SP -= 1; // SP == 997

    stack[SP] = stack[SP + 1] * 3;
    AX = stack[SP];

    SP += 1; // finally we can cleanup locals right in the function body, SP == 998

void main(){
    ... // some code
    push(AX); // save AX in case there is something useful there, SP == 999
    push(11); // SP == 998
    assert(triple(11) == AX);
    SP += 1; // cleanup param
             // locals were cleaned up in the function body, so we don't need to do it here
    pop(AX); // restore AX

8. Stack base pointer (BP) (also known as frame pointer) and stack frame

Lets take more "advanced" function and rewrite it in our asm-like C++ (snippet #8.1):

int myAlgo(int a, int b) {
    int t1 = a * 3;
    int t2 = b * 3;
    return t1 - t2;

void myAlgo_noLPR() { // `a` at 997, `b` at 998, old AX at 999, SP == 997
    SP -= 2; // SP == 995

    stack[SP + 1] = stack[SP + 2] * 3; 
    stack[SP]     = stack[SP + 3] * 3;
    AX = stack[SP + 1] - stack[SP];

    SP += 2; // cleanup locals, SP == 997

int main(){
    push(AX); // SP == 999
    push(22); // SP == 998
    push(11); // SP == 997
    assert(myAlgo(11, 22) == AX);
    SP += 2;

Now imagine we decided to introduce new local variable to store result there before returning, as we do in tripple (snippet #4.1). The body of the function will be (snippet #8.2):

SP -= 3; // SP == 994
stack[SP + 2] = stack[SP + 3] * 3; 
stack[SP + 1] = stack[SP + 4] * 3;
stack[SP]     = stack[SP + 2] - stack[SP + 1];
AX = stack[SP];
SP += 3;

You see, we had to update every single reference to function parameters and local variables. To avoid that, we need an anchor index, which doesn't change when the stack grows.

We will create the anchor right upon function entry (before we allocate space for locals) by saving current top (value of SP) into BP register. Snippet #8.3:

void myAlgo_noLPR_withAnchor() { // `a` at 997, `b` at 998, SP == 997
    push(BP);   // save old BP, SP == 996
    BP = SP;    // create anchor, stack[BP] == old value of BP, now BP == 996
    SP -= 2;    // SP == 994

    stack[BP - 1] = stack[BP + 1] * 3;
    stack[BP - 2] = stack[BP + 2] * 3;
    AX = stack[BP - 1] - stack[BP - 2];

    SP = BP;    // cleanup locals, SP == 996
    pop(BP);    // SP == 997

The slice of stack, wich belongs to and is in full control of the function is called function's stack frame. E.g. myAlgo_noLPR_withAnchor's stack frame is stack[996 .. 994] (both idexes inclusive).
Frame starts at function's BP (after we've updated it inside function) and lasts until the next stack frame. So the parameters on the stack are part of the caller's stack frame (see note 8a).

8a. Wikipedia says otherwise about parameters, but here I adhere to Intel software developer's manual, see vol. 1, section Stack-Frame Base Pointer and Figure 6-2 in section 6.3.2 Far CALL and RET Operation. Function's parameters and stack frame are part of function's activation record (see The gen on function perilogues).
8b. positive offsets from BP point to function parameters and negative offsets point to local variables. That's pretty handy for debugging
8c. stack[BP] stores the address of the previous stack frame, stack[stack[BP]] stores pre-previous stack frame and so on. Following this chain, you can discover frames of all the functions in the programm, which didn't return yet. This is how debuggers show you call stack
8d. the first 3 instructions of myAlgo_noLPR_withAnchor, where we setup the frame (save old BP, update BP, reserve space for locals) are called function prologue

9. Calling conventions

In snippet 8.1 we've pushed parameters for myAlgo from right to left and returned result in AX. We could as well pass params left to right and return in BX. Or pass params in BX and CX and return in AX. Obviously, caller (main()) and called function must agree where and in which order all this stuff is stored.

Calling convention is a set of rules on how parameters are passed and result is returned.

In the code above we've used cdecl calling convention:

  • Parameters are passed on the stack, with the first argument at the lowest address on the stack at the time of the call (pushed last <...>). The caller is responsible for popping parameters back off the stack after the call.
  • the return value is placed in AX
  • EBP and ESP must be preserved by the callee (myAlgo_noLPR_withAnchor function in our case), such that the caller (main function) can rely on those registers not having been changed by a call.
  • All other registers (EAX, <...>) may be freely modified by the callee; if a caller wishes to preserve a value before and after the function call, it must save the value elsewhere (we do this with AX)

(Source: example "32-bit cdecl" from Stack Overflow Documentation; copyright 2016 by icktoofay and Peter Cordes ; licensed under CC BY-SA 3.0. An archive of the full Stack Overflow Documentation content can be found at, in which this example is indexed by topic ID 3261 and example ID 11196.)

10. Function calls

Now the most interesting part. Just like data, executable code is also stored in memory (completely unrelated to memory for stack) and every instruction has an address.
When not commanded otherwise, CPU executes instructions one after another, in the order they are stored in memory. But we can command CPU to "jump" to another location in memory and execute instructions from there on. In asm it can be any address, and in more high-level languages like C++ you can only jump to addresses marked by labels (there are workarounds but they are not pretty, to say the least).

Let's take this function (snippet #10.1):

int myAlgo_withCalls(int a, int b) {
    int t1 = triple(a);
    int t2 = triple(b);
    return t1 - t2;

And instead of calling tripple C++ way, do the following:

  1. copy tripple's code to the beginning of myAlgo body
  2. at myAlgo entry jump over tripple's code with goto
  3. when we need to execute tripple's code, save on the stack address of the code line just after tripple call, so we can return here later and continue execution (PUSH_ADDRESS macro below)
  4. jump to the address of the 1st line (tripple function) and execute it to the end (3. and 4. together are CALL macro)
  5. at the end of the tripple (after we've cleaned up locals), take return address from the top of the stack and jump there (RET macro)

Because there is no easy way to jump to particular code address in C++, we will use labels to mark places of jumps. I won't go into detail how macros below work, just believe me they do what I say they do (snippet #10.2):

// pushes the address of the code at label's location on the stack
// NOTE1: this gonna work only with 32-bit compiler (so that pointer is 32-bit and fits in int)
// NOTE2: __asm block is specific for Visual C++. In GCC use
#define PUSH_ADDRESS(labelName) {               \
    void* tmpPointer;                           \
    __asm{ mov [tmpPointer], offset labelName } \
    push(reinterpret_cast<int>(tmpPointer));    \

// why we need indirection, read
#define TOKENPASTE(x, y) x ## y
#define TOKENPASTE2(x, y) TOKENPASTE(x, y)

// generates token (not a string) we will use as label name. 
// Example: LABEL_NAME(155) will generate token `lbl_155`
#define LABEL_NAME(num) TOKENPASTE2(lbl_, num)

#define CALL_IMPL(funcLabelName, callId)    \
    PUSH_ADDRESS(LABEL_NAME(callId));       \
    goto funcLabelName;                     \
    LABEL_NAME(callId) :

// saves return address on the stack and jumps to label `funcLabelName`
#define CALL(funcLabelName) CALL_IMPL(funcLabelName, __LINE__)

// takes address at the top of stack and jump there
#define RET() {                                         \
    int tmpInt;                                         \
    pop(tmpInt);                                        \
    void* tmpPointer = reinterpret_cast<void*>(tmpInt); \
    __asm{ jmp tmpPointer }                             \

void myAlgo_asm() {
    goto my_algo_start;

    BP = SP;
    SP -= 1;

    // stack[BP] == old BP, stack[BP + 1] == return address
    stack[BP - 1] = stack[BP + 2] * 3;
    AX = stack[BP - 1];

    SP = BP;     

    push(BP);   // SP == 995
    BP = SP;    // BP == 995; stack[BP] == old BP, 
                // stack[BP + 1] == dummy return address, 
                // `a` at [BP + 2], `b` at [BP + 3]
    SP -= 2;    // SP == 993

    push(stack[BP + 2]);
    stack[BP - 1] = AX;
    SP -= 1;

    push(stack[BP + 3]);
    stack[BP - 2] = AX;
    SP -= 1;

    AX = stack[BP - 1] - stack[BP - 2];

    SP = BP; // cleanup locals, SP == 997

int main() {
    push(7777); // dummy value, so that offsets inside function are like we've pushed return address
    assert(myAlgo_withCalls(11, 22) == AX);
    SP += 1; // pop dummy "return address"
    SP += 2;

10a. because return address is stored on the stack, in principle we can change it. This is how stack smashing attack works
10b. the last 3 instructions at the "end" of triple_label (cleanup locals, restore old BP, return) are called function's epilogue

11. Assembly

Now let's look at real asm for myAlgo_withCalls. To do that in Visual Studio:

  • set build platform to x86 (not x86_64)
  • build type: Debug
  • set break point somewhere inside myAlgo_withCalls
  • run, and when execution stops at break point press Ctrl + Alt + D

One difference with our asm-like C++ is that asm's stack operate on bytes instead of ints. So to reserve space for one int, SP will be decremented by 4 bytes.
Here we go (snippet #11.1, line numbers in comments are from the gist):

;   114: int myAlgo_withCalls(int a, int b) {
 push        ebp        ; create stack frame 
 mov         ebp,esp  
; return address at (ebp + 4), `a` at (ebp + 8), `b` at (ebp + 12)
 sub         esp,0D8h   ; reserve space for locals. Compiler can reserve more bytes then needed. 0D8h is hexadecimal == 216 decimal 
 push        ebx        ; cdecl requires to save all these registers
 push        esi  
 push        edi  
 ; fill all the space for local variables (from (ebp-0D8h) to (ebp)) with value 0CCCCCCCCh repeated 36h times (36h * 4 == 0D8h)
 ; see
 ; I guess that's for ease of debugging, so that stack is filled with recognizable values
 ; 0CCCCCCCCh in binary is 110011001100...
 lea         edi,[ebp-0D8h]     
 mov         ecx,36h    
 mov         eax,0CCCCCCCCh  
 rep stos    dword ptr es:[edi]  
;   115:    int t1 = triple(a);
 mov         eax,dword ptr [ebp+8]   ; push parameter `a` on the stack
 push        eax  
 call        triple (01A13E8h)  
 add         esp,4                   ; clean up param 
 mov         dword ptr [ebp-8],eax   ; copy result from eax to `t1`
;   116:    int t2 = triple(b);
 mov         eax,dword ptr [ebp+0Ch] ; push `b` (0Ch == 12)
 push        eax  
 call        triple (01A13E8h)  
 add         esp,4  
 mov         dword ptr [ebp-14h],eax ; t2 = eax
 mov         eax,dword ptr [ebp-8]   ; calculate and store result in eax
 sub         eax,dword ptr [ebp-14h]  

 pop         edi  ; restore registers
 pop         esi  
 pop         ebx  
 add         esp,0D8h  ; check we didn't mess up esp or ebp. this is only for debug builds
 cmp         ebp,esp  
 call        __RTC_CheckEsp (01A116Dh)  
 mov         esp,ebp  ; destroy frame
 pop         ebp  

And asm for tripple (snippet #11.2):

 push        ebp  
 mov         ebp,esp  
 sub         esp,0CCh  
 push        ebx  
 push        esi  
 push        edi  
 lea         edi,[ebp-0CCh]  
 mov         ecx,33h  
 mov         eax,0CCCCCCCCh  
 rep stos    dword ptr es:[edi]  
 imul        eax,dword ptr [ebp+8],3  
 mov         dword ptr [ebp-8],eax  
 mov         eax,dword ptr [ebp-8]  
 pop         edi  
 pop         esi  
 pop         ebx  
 mov         esp,ebp  
 pop         ebp  

Hope, after reading this post, assembly doesn't look as cryptic as before :)

Here are links from the post's body and some further reading:

Get user input from textarea

  <input type="text"  #titleInput>
  <button type="submit" (click) = 'addTodo(titleInput.value)'>Add</button>

  addTodo(title:string) {

How to receive POST data in django

You should have access to the POST dictionary on the request object.

TypeScript, Looping through a dictionary

Shortest way to get all dictionary/object values:

Object.keys(dict).map(k => dict[k]);

Android requires compiler compliance level 5.0 or 6.0. Found '1.7' instead. Please use Android Tools > Fix Project Properties

I agree with BMSAndroidDroid and Flo-Scheild-Bobby. I was doing a tutorial called DailyQuote and had used the Cordova library. I then changed my OS from Windows to Ubuntu and tried to import projects into Eclipse, (I'm using Eclipse Juno 64-bit, on Ubuntu 12.04 64-bit, Oracle JDK 7. I also installed the Ubuntu 32-bit libs- so no issues with 64 and 32bit), and got the same issue.

As suggested by Flo-Scheild-Bobby, open configure build path and add the jar(s) again that you added before. Then remove the old jar link(s) and thats it.

Hash function for a string

First, it usually does not matter that much in practice. Most hash functions are "good enough".

But if you really care, you should know that it is a research subject by itself. There are thousand of papers about that. You can still get a PhD today by studying & designing hashing algorithms.

Your second hash function might be slightly better, because it probably should separate the string "ab" from the string "ba". On the other hand, it is probably less quick than the first hash function. It may, or may not, be relevant for your application.

I'll guess that hash functions used for genome strings are quite different than those used to hash family names in telephone databases. Perhaps even some string hash functions are better suited for German, than for English or French words.

Many software libraries give you good enough hash functions, e.g. Qt has qhash, and C++11 has std::hash in <functional>, Glib has several hash functions in C, and POCO has some hash function.

I quite often have hashing functions involving primes (see Bézout's identity) and xor, like e.g.

#define A 54059 /* a prime */
#define B 76963 /* another prime */
#define C 86969 /* yet another prime */
#define FIRSTH 37 /* also prime */
unsigned hash_str(const char* s)
   unsigned h = FIRSTH;
   while (*s) {
     h = (h * A) ^ (s[0] * B);
   return h; // or return h % C;

But I don't claim to be an hash expert. Of course, the values of A, B, C, FIRSTH should preferably be primes, but you could have chosen other prime numbers.

Look at some MD5 implementation to get a feeling of what hash functions can be.

Most good books on algorithmics have at least a whole chapter dedicated to hashing. Start with wikipages on hash function & hash table.

What's the HTML to have a horizontal space between two objects?

I think what you mean is putting 2 paragraphs (for example) in 2 columns instead of one below the other? In that case, I think float is your solution.

<div style="float: left"> <!-- would cause this to hang on the left -->
<div style="float: right"> <!-- would cause this to hang on the right-->

Here's an example:

Removing the password from a VBA project

This has a simple method using SendKeys to unprotect the VBA project. This would get you into the project, so you'd have to continue on using SendKeys to figure out a way to remove the password protection:

And here's one that uses a more advanced, somewhat more reliable method for unprotecting. Again, it will only unlock the VB project for you.

I haven't tried either method, but this may save you some time if it's what you need to do...

Remove HTML tags from a String

The accepted answer did not work for me for the test case I indicated: the result of "a < b or b > c" is "a b or b > c".

So, I used TagSoup instead. Here's a shot that worked for my test case (and a couple of others):

import java.util.logging.Logger;

import org.ccil.cowan.tagsoup.Parser;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.InputSource;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;

 * Take HTML and give back the text part while dropping the HTML tags.
 * There is some risk that using TagSoup means we'll permute non-HTML text.
 * However, it seems to work the best so far in test cases.
 * @author dan
 * @see <a href="">TagSoup</a> 
public class Html2Text2 implements ContentHandler {
private StringBuffer sb;

public Html2Text2() {

public void parse(String str) throws IOException, SAXException {
    XMLReader reader = new Parser();
    sb = new StringBuffer();
    reader.parse(new InputSource(new StringReader(str)));

public String getText() {
    return sb.toString();

public void characters(char[] ch, int start, int length)
    throws SAXException {
    for (int idx = 0; idx < length; idx++) {

public void ignorableWhitespace(char[] ch, int start, int length)
    throws SAXException {

// The methods below do not contribute to the text
public void endDocument() throws SAXException {

public void endElement(String uri, String localName, String qName)
    throws SAXException {

public void endPrefixMapping(String prefix) throws SAXException {

public void processingInstruction(String target, String data)
    throws SAXException {

public void setDocumentLocator(Locator locator) {

public void skippedEntity(String name) throws SAXException {

public void startDocument() throws SAXException {

public void startElement(String uri, String localName, String qName,
    Attributes atts) throws SAXException {

public void startPrefixMapping(String prefix, String uri)
    throws SAXException {

Javascript - Append HTML to container element without innerHTML

This is what DocumentFragment was meant for.

var frag = document.createDocumentFragment();
var span = document.createElement("span");
span.innerHTML = htmldata;
for (var i = 0, ii = span.childNodes.length; i < ii; i++) {

document.createDocumentFragment, .childNodes

Start new Activity and finish current one in Android?

FLAG_ACTIVITY_NO_HISTORY when starting the activity you wish to finish after the user goes to another one.

How to select element using XPATH syntax on Selenium for Python?

Check this blog by Martin Thoma. I tested the below code on MacOS Mojave and it worked as specified.

> def get_browser():
>     """Get the browser (a "driver")."""
>     # find the path with 'which chromedriver'
>     path_to_chromedriver = ('/home/moose/GitHub/algorithms/scraping/'
>                             'venv/bin/chromedriver')
>     download_dir = "/home/moose/selenium-download/"
>     print("Is directory: {}".format(os.path.isdir(download_dir)))
>     from import Options
>     chrome_options = Options()
>     chrome_options.add_experimental_option('prefs', {
>         "plugins.plugins_list": [{"enabled": False,
>                                   "name": "Chrome PDF Viewer"}],
>         "download": {
>             "prompt_for_download": False,
>             "default_directory": download_dir
>         }
>     })
>     browser = webdriver.Chrome(path_to_chromedriver,
>                                chrome_options=chrome_options)
>     return browser

What is the purpose of the var keyword and when should I use it (or omit it)?

Using var is always a good idea to prevent variables from cluttering the global scope and variables from conflicting with each other, causing unwanted overwriting.

How to format date and time in Android?

Following this:

Is better to use Android native Time class:

Time now = new Time();

Then format:

Log.d("DEBUG", "Time "+now.format("%d.%m.%Y %H.%M.%S"));

Head and tail in one line

Under Python 3.x, you can do this nicely:

>>> head, *tail = [1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
>>> head
>>> tail
[1, 2, 3, 5, 8, 13, 21, 34, 55]

A new feature in 3.x is to use the * operator in unpacking, to mean any extra values. It is described in PEP 3132 - Extended Iterable Unpacking. This also has the advantage of working on any iterable, not just sequences.

It's also really readable.

As described in the PEP, if you want to do the equivalent under 2.x (without potentially making a temporary list), you have to do this:

it = iter(iterable)
head, tail = next(it), list(it)

As noted in the comments, this also provides an opportunity to get a default value for head rather than throwing an exception. If you want this behaviour, next() takes an optional second argument with a default value, so next(it, None) would give you None if there was no head element.

Naturally, if you are working on a list, the easiest way without the 3.x syntax is:

head, tail = seq[0], seq[1:]

Quick Way to Implement Dictionary in C

For ease of implementation, it's hard to beat naively searching through an array. Aside from some error checking, this is a complete implementation (untested).

typedef struct dict_entry_s {
    const char *key;
    int value;
} dict_entry_s;

typedef struct dict_s {
    int len;
    int cap;
    dict_entry_s *entry;
} dict_s, *dict_t;

int dict_find_index(dict_t dict, const char *key) {
    for (int i = 0; i < dict->len; i++) {
        if (!strcmp(dict->entry[i], key)) {
            return i;
    return -1;

int dict_find(dict_t dict, const char *key, int def) {
    int idx = dict_find_index(dict, key);
    return idx == -1 ? def : dict->entry[idx].value;

void dict_add(dict_t dict, const char *key, int value) {
   int idx = dict_find_index(dict, key);
   if (idx != -1) {
       dict->entry[idx].value = value;
   if (dict->len == dict->cap) {
       dict->cap *= 2;
       dict->entry = realloc(dict->entry, dict->cap * sizeof(dict_entry_s));
   dict->entry[dict->len].key = strdup(key);
   dict->entry[dict->len].value = value;

dict_t dict_new(void) {
    dict_s proto = {0, 10, malloc(10 * sizeof(dict_entry_s))};
    dict_t d = malloc(sizeof(dict_s));
    *d = proto;
    return d;

void dict_free(dict_t dict) {
    for (int i = 0; i < dict->len; i++) {

VBA copy rows that meet criteria to another sheet

You need to specify workseet. Change line

If Worksheet.Cells(i, 1).Value = "X" Then


If Worksheets("Sheet2").Cells(i, 1).Value = "X" Then


Try to use following code (but it's not the best approach. As @SiddharthRout suggested, consider about using Autofilter):

Sub LastRowInOneColumn()
   Dim LastRow As Long
   Dim i As Long, j As Long

   'Find the last used row in a Column: column A in this example
   With Worksheets("Sheet2")
      LastRow = .Cells(.Rows.Count, "A").End(xlUp).Row
   End With

   MsgBox (LastRow)
   'first row number where you need to paste values in Sheet1'
   With Worksheets("Sheet1")
      j = .Cells(.Rows.Count, "A").End(xlUp).Row + 1
   End With 

   For i = 1 To LastRow
       With Worksheets("Sheet2")
           If .Cells(i, 1).Value = "X" Then
               .Rows(i).Copy Destination:=Worksheets("Sheet1").Range("A" & j)
               j = j + 1
           End If
       End With
   Next i
End Sub

How to create and download a csv file from php script?

If you're array structure will always be multi-dimensional in that exact fashion, then we can iterate through the elements like such:

$fh = fopen('somefile.csv', 'w') or die('Cannot open the file');

for( $i=0; $i<count($arr); $i++ ){
    $str = implode( ',', $arr[$i] );
    fwrite( $fh, $str );
    fwrite( $fh, "\n" );

That's one way to do it ... you could do it manually but this way is quicker and easier to understand and read.

Then you would manage your headers something what complex857 is doing to spit out the file. You could then delete the file using unlink() if you no longer needed it, or you could leave it on the server if you wished.

Converting Pandas dataframe into Spark dataframe error

Type related errors can be avoided by imposing a schema as follows:

note: a text file was created (test.csv) with the original data (as above) and hypothetical column names were inserted ("col1","col2",...,"col25").

import pyspark
from pyspark.sql import SparkSession
import pandas as pd

spark = SparkSession.builder.appName('pandasToSparkDF').getOrCreate()

pdDF = pd.read_csv("test.csv")

contents of the pandas data frame:

       col1     col2    col3    col4    col5    col6    col7    col8   ... 
0      10000001 1       0       1       12:35   OK      10002   1      ...
1      10000001 2       0       1       12:36   OK      10002   1      ...
2      10000002 1       0       4       12:19   PA      10003   1      ...

Next, create the schema:

from pyspark.sql.types import *

mySchema = StructType([ StructField("col1", LongType(), True)\
                       ,StructField("col2", IntegerType(), True)\
                       ,StructField("col3", IntegerType(), True)\
                       ,StructField("col4", IntegerType(), True)\
                       ,StructField("col5", StringType(), True)\
                       ,StructField("col6", StringType(), True)\
                       ,StructField("col7", IntegerType(), True)\
                       ,StructField("col8", IntegerType(), True)\
                       ,StructField("col9", IntegerType(), True)\
                       ,StructField("col10", IntegerType(), True)\
                       ,StructField("col11", StringType(), True)\
                       ,StructField("col12", StringType(), True)\
                       ,StructField("col13", IntegerType(), True)\
                       ,StructField("col14", IntegerType(), True)\
                       ,StructField("col15", IntegerType(), True)\
                       ,StructField("col16", IntegerType(), True)\
                       ,StructField("col17", IntegerType(), True)\
                       ,StructField("col18", IntegerType(), True)\
                       ,StructField("col19", IntegerType(), True)\
                       ,StructField("col20", IntegerType(), True)\
                       ,StructField("col21", IntegerType(), True)\
                       ,StructField("col22", IntegerType(), True)\
                       ,StructField("col23", IntegerType(), True)\
                       ,StructField("col24", IntegerType(), True)\
                       ,StructField("col25", IntegerType(), True)])

Note: True (implies nullable allowed)

create the pyspark dataframe:

df = spark.createDataFrame(pdDF,schema=mySchema)

confirm the pandas data frame is now a pyspark data frame:





To address Kate's comment below - to impose a general (String) schema you can do the following:


Using sed and grep/egrep to search and replace

I couldn't get any of the commands on this page to work for me: the sed solution added a newline to the end of all the files it processed, and the perl solution was unable to accept enough arguments from find. I found this solution which works perfectly:

find . -type f -name '*.[hm]' -print0 
    | xargs -0 perl -pi -e 's/search_regex/replacement_string/g'

This will recurse down the current directory tree and replace search_regex with replacement_string in any files ending in .h or .m.

I have also used rpl for this purpose in the past.

error: package javax.servlet does not exist

I got here with a similar problem with my Gradle build and fixed it in a similar way:

Unable to load class hudson.model.User due to missing dependency javax/servlet/ServletException

fixed with:

dependencies {

How to move a file?

  import os,shutil

  current_path = "" ## source path

  new_path = "" ## destination path


  for files in os.listdir():

        os.rename(files, new_path+'{}'.format(f))
        shutil.move(files, new_path+'{}'.format(f)) ## to move files from 

different disk ex. C: --> D:

How to find unused/dead code in java projects

  • FindBugs is excellent for this sort of thing.
  • PMD (Project Mess Detector) is another tool that can be used.

However, neither can find public static methods that are unused in a workspace. If anyone knows of such a tool then please let me know.

Align button to the right

The bootstrap 4.0.0 file you are getting from cdn doesn't have a pull-right (or pull-left) class. The v4 is in alpha, so there are many issues like that.

There are 2 options:

1) Reverse to bootstrap 3.3.7

2) Write your own CSS.

How do pointer-to-pointer's work in C? (and when might you use them?)

Let's assume an 8 bit computer with 8 bit addresses (and thus only 256 bytes of memory). This is part of that memory (the numbers at the top are the addresses):

  54   55   56   57   58   59   60   61   62   63   64   65   66   67   68   69
|    | 58 |    |    | 63 |    | 55 |    |    | h  | e  | l  | l  | o  | \0 |    |

What you can see here, is that at address 63 the string "hello" starts. So in this case, if this is the only occurrence of "hello" in memory then,

const char *c = "hello";

... defines c to be a pointer to the (read-only) string "hello", and thus contains the value 63. c must itself be stored somewhere: in the example above at location 58. Of course we can not only point to characters, but also to other pointers. E.g.:

const char **cp = &c;

Now cp points to c, that is, it contains the address of c (which is 58). We can go even further. Consider:

const char ***cpp = &cp;

Now cpp stores the address of cp. So it has value 55 (based on the example above), and you guessed it: it is itself stored at address 60.

As to why one uses pointers to pointers:

  • The name of an array usually yields the address of its first element. So if the array contains elements of type t, a reference to the array has type t *. Now consider an array of arrays of type t: naturally a reference to this 2D array will have type (t *)* = t **, and is hence a pointer to a pointer.
  • Even though an array of strings sounds one-dimensional, it is in fact two-dimensional, since strings are character arrays. Hence: char **.
  • A function f will need to accept an argument of type t ** if it is to alter a variable of type t *.
  • Many other reasons that are too numerous to list here.

Why can I not switch branches?

You end up with both modified in the output of git status if there were conflicts produced by a merge. git isn't letting you change branch until you've resolved these conflicts. If you edit that file, you should see some conflict markers in it - there's a guide to resolving those conflicts in the git manual. (Since is currently down, you can find that guide here instead.)

Alternatively, if you think the merge was a mistake, you could undo it with: git reset --merge

Xml Parsing in C#

First add an Enrty and Category class:

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

Then use LINQ to XML

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

How to fix request failed on channel 0

As you already found the -T flag that create a PTY, I will just respond to the second part:

shell request failed on channel 0

You should pass a command:

ssh [email protected] -p 22 help

After reading back the manual here:, I find it not really clear that it would not work without a command. But as stated by @U.V., the ssh interface is not a console interface, rather a connection utility. So you need to pass a command...

If someone from the "jenkins" team pass accross this post, it would be great that if we pass no command, the help would show up :-)

How to detect when a UIScrollView has finished scrolling

If somebody needs, here's Ashley Smart answer in Swift

func scrollViewDidScroll(_ scrollView: UIScrollView) {
        NSObject.cancelPreviousPerformRequests(withTarget: self)
        perform(#selector(UIScrollViewDelegate.scrollViewDidEndScrollingAnimation), with: nil, afterDelay: 0.3)

func scrollViewDidEndScrollingAnimation(_ scrollView: UIScrollView) {
        NSObject.cancelPreviousPerformRequests(withTarget: self)

Global variable Python classes

What you have is correct, though you will not call it global, it is a class attribute and can be accessed via class e.g Shape.lolwut or via an instance e.g. shape.lolwut but be careful while setting it as it will set an instance level attribute not class attribute

class Shape(object):
    lolwut = 1

shape = Shape()

print Shape.lolwut,  # 1
print shape.lolwut,  # 1

# setting shape.lolwut would not change class attribute lolwut 
# but will create it in the instance
shape.lolwut = 2

print Shape.lolwut,  # 1
print shape.lolwut,  # 2

# to change class attribute access it via class
Shape.lolwut = 3

print Shape.lolwut,  # 3
print shape.lolwut   # 2 


1 1 1 2 3 2

Somebody may expect output to be 1 1 2 2 3 3 but it would be incorrect

How to create image slideshow in html?

Instead of writing the code from the scratch you can use jquery plug in. Such plug in can provide many configuration option as well.

Here is the one I most liked.

Postgres integer arrays as parameters?

I realize this is an old question, but it took me several hours to find a good solution and thought I'd pass on what I learned here and save someone else the trouble. Try, for example,

SELECT * FROM some_table WHERE id_column = ANY(@id_list)

where @id_list is bound to an int[] parameter by way of

command.Parameters.Add("@id_list", NpgsqlDbType.Array | NpgsqlDbType.Integer).Value = my_id_list;

where command is a NpgsqlCommand (using C# and Npgsql in Visual Studio).

Sleep for milliseconds

If using MS Visual C++ 10.0, you can do this with standard library facilities:


you will need:

#include <concrt.h>

Sum up a column from a specific row down

You all seem to love complication. Just click on column(to select entire column), press and hold CTRL and click on cells that you want to exclude(C1 to C5 in you case). Now you have selected entire column C (right to the end of sheet) without starting cells. All you have to do now is to rightclick and "Define Name" for your selection(ex. asdf ). In formula you use SUM(asdf). And now you're done. Good luck

Allways find the easyest way ;)

Local storage in Angular 2

The syntax of set item is


The syntax of get item is


An example of this is:

localStorage.setItem('email','[email protected]');
    let mail = localStorage.getItem("email");
       console.log('your email id is', mail);

AngularJS: Insert HTML from a string

you can also use $sce.trustAsHtml('"<h1>" + str + "</h1>"'),if you want to know more detail, please refer to $sce

int to hex string

Previous answer is not good for negative numbers. Use a short type instead of int

        short iValue = -1400;
        string sResult = iValue.ToString("X2");
        Console.WriteLine("Value={0} Result={1}", iValue, sResult);

Now result is FA88

Hide element by class in pure Javascript

var appBanners = document.getElementsByClassName('appBanner');

for (var i = 0; i < appBanners.length; i ++) {
    appBanners[i].style.display = 'none';


JPA getSingleResult() or null

Here's a typed/generics version, based on Rodrigo IronMan's implementation:

 public static <T> T getSingleResultOrNull(TypedQuery<T> query) {
    List<T> list = query.getResultList();
    if (list.isEmpty()) {
        return null;
    return list.get(0);

What does the error "JSX element type '...' does not have any construct or call signatures" mean?

The following worked for me: I fix it by doing something like this:

const Component = (isFoo ? FooComponent : BarComponent) as React.ElementType

Could not reserve enough space for object heap

Replace -Xmx2G with -Xms512M or any greater memory size in cassandra.bat file in cassandra bin directory.

Return in Scala

Don't write if statements without a corresponding else. Once you add the else to your fragment you'll see that your true and false are in fact the last expressions of the function.

def balanceMain(elem: List[Char]): Boolean =
    if (elem.isEmpty)
      if (count == 0)
      if (elem.head == '(')
        balanceMain(elem.tail, open, count + 1)

What does "<html xmlns="">" do?

The namespace name 
is intended for use in various specifications such as:


    XHTML™ 1.0: The Extensible HyperText Markup Language
    XHTML Modularization
    XHTML 1.1
    XHTML Basic
    XHTML Print

Check here for more detail

Read and parse a Json File in C#

This code can help you:

string _filePath = Path.GetDirectoryName(System.AppDomain.CurrentDomain.BaseDirectory);

JObject data = JObject.Parse(_filePath );

Undefined symbols for architecture i386: _OBJC_CLASS_$_SKPSMTPMessage", referenced from: error

Also could be that you're missing to link against a Binary Library, check Build Phases in your Targes add required libraries and then Product > Clean Product > Build

That must work too!

Retrieving Android API version programmatically

Like this:

String versionRelease = BuildConfig.VERSION_NAME;

versionRelease :- 2.1.17

Please make sure your import package is correct ( import package your_application_package_name, otherwise it will not work properly).

How do I decode a URL parameter using C#?


Get the IP address of the machine

As the question specifies Linux, my favourite technique for discovering the IP-addresses of a machine is to use netlink. By creating a netlink socket of the protocol NETLINK_ROUTE, and sending an RTM_GETADDR, your application will received a message(s) containing all available IP addresses. An example is provided here.

In order to simply parts of the message handling, libmnl is convenient. If you are curios in figuring out more about the different options of NETLINK_ROUTE (and how they are parsed), the best source is the source code of iproute2 (especially the monitor application) as well as the receive functions in the kernel. The man page of rtnetlink also contains useful information.

iOS / Android cross platform development

Disclaimer: I work for a company, Particle Code, that makes a cross-platform framework. There are a ton of companies in this space. New ones seem to spring up every week. Good news for you: you have a lot of choices.

These frameworks take different approaches, and many of them are fundamentally designed to solve different problems. Some are focused on games, some are focused on apps. I would ask the following questions:

What do you want to write? Enterprise application, personal productivity application, puzzle game, first-person shooter?

What kind of development environment do you prefer? IDE or plain ol' text editor?

Do you have strong feelings about programming languages? Of the frameworks I'm familiar with, you can choose from ActionScript, C++, C#, Java, Lua, and Ruby.

My company is more in the game space, so I haven't played as much with the JavaScript+CSS frameworks like Titanium, PhoneGap, and Sencha. But I can tell you a bit about some of the games-oriented frameworks. Games and rich internet applications are an area where cross-platform frameworks can shine, because these applications tend to place more importance of being visually unique and less on blending in with native UIs. Here are a few frameworks to look for:

  • Unity is a 3D games engine. It's really unlike any other development environment I've worked in. You build scenes with 3D models, and define behavior by attaching scripts to objects. You can script in JavaScript, C#, or Boo. If you want to write a 3D physics-based game that will run on iOS, Android, Windows, OS X, or consoles, this is probably the tool for you. You can also write 2D games using 3D assets--a fine example of this is indie game Max and the Magic Marker, a 2D physics-based side-scroller written in Unity. If you don't know it, I recommend checking it out (especially if there are any kids in your household). Max is available for PC, Wii, iOS and Windows Phone 7 (although the latter version is a port, since Unity doesn't support WinPhone). Unity comes with some sample games complete with 3D assets and textures, which really helps getting up to speed with what can be a pretty complicated environment.

  • Corona is a 2D games engine that uses the Lua scripting language and supports iOS and Android. The selling point of Corona is the ability to write physics-based games very quickly in few lines of code, and the large number of Corona-based games in the iOS app store is a testament to its success. The environment is very lean, which will appeal to some people. It comes with a simulator and debugger. You add your text editor of choice, and you have a development environment. The base SDK doesn't include any UI components, like buttons or list boxes, but a CoronaUI add-on is available to subscribers.

  • The Particle SDK is a slightly more general cross-platform solution with a background in games. You can write in either Java or ActionScript, using a MVC application model. It includes an Eclipse-based IDE with a WYSIWYG UI editor. We currently support building for Android, iOS, webOS, and Windows Phone 7 devices. You can also output Flash or HTML5 for the web. The framework was originally developed for online multiplayer social games, such as poker and backgammon, and it suits 2D games and apps with complex logic. The framework supports 2D graphics and includes a 2D physics engine.


Today we announced that Particle Code has been acquired by Appcelerator, makers of the Titanium cross-platform framework.


As of January 1, 2012, [Particle Code] will no longer officially support the [Particle SDK] platform.


  • The Airplay SDK is a C++ framework that lets you develop in either Visual Studio or Xcode. It supports both 2D and 3D graphics. Airplay targets iOS, Android, Bada, Symbian, webOS, and Windows Mobile 6. They also have an add-on to build AirPlay apps for PSP. My C++ being very rusty, I haven't played with it much, but it looks cool.

In terms of learning curve, I'd say that Unity had the steepest learning curve (for me), Corona was the simplest, and Particle and Airplay are somewhere in between.

Another interesting point is how the frameworks handle different form factors. Corona supports dynamic scaling, which will be familiar to Flash developers. This is very easy to use but means that you end up wasting screen space when going from a 4:3 screen like the iPhone to a 16:9 like the new qHD Android devices. The Particle SDK's UI editor lets you design flexible layouts that scale, but also lets you adjust the layouts for individual screen sizes. This takes a little more time but lets you make the app look custom made for each screen.

Of course, what works for you depends on your individual taste and work style as well as your goals -- so I recommend downloading a couple of these tools and giving them a shot. All of these tools are free to try.

Also, if I could just put in a public service announcement -- most of these tools are in really active development. If you find a framework you like, by all means send feedback and let them know what you like, what you don't like, and features you'd like to see. You have a real opportunity to influence what goes into the next versions of these tools.

Hope this helps.

Winforms issue - Error creating window handle

I think it's normally related to the computer running out of memory so it's not able to create any more window handles. Normally windows starts to show some strange behavior at this point as well.

How to find prime numbers between 0 - 100?

A list built using the new features of ES6, especially with generator. Go to made in Catalan language for classes with my students. I hope you find it useful.

function* Primer(max) { _x000D_
  const infinite = !max && max !== 0;_x000D_
  const re = /^.?$|^(..+?)\1+$/; _x000D_
  let current = 1;_x000D_
  while (infinite || max-- ) {_x000D_
      if(!re.test('1'.repeat(current)) == true) yield current;_x000D_
let [...list] = Primer(100); _x000D_

Get number days in a specified month using JavaScript?

// Month here is 1-indexed (January is 1, February is 2, etc). This is
// because we're using 0 as the day so that it returns the last day
// of the last month, so you have to add 1 to the month number 
// so it returns the correct amount of days
function daysInMonth (month, year) {
    return new Date(year, month, 0).getDate();

// July
daysInMonth(7,2009); // 31
// February
daysInMonth(2,2009); // 28
daysInMonth(2,2008); // 29

Hex-encoded String to Byte Array

I think what the questioner is after is converting the string representation of a hexadecimal value to a byte array representing that hexadecimal value.

The apache commons-codec has a class for that, Hex.

String s = "9B7D2C34A366BF890C730641E6CECF6F";    
byte[] bytes = Hex.decodeHex(s.toCharArray());

Normalizing images in OpenCV

If you want to change the range to [0, 1], make sure the output data type is float.

image = cv2.imread("lenacolor512.tiff", cv2.IMREAD_COLOR)  # uint8 image
norm_image = cv2.normalize(image, None, alpha=0, beta=1, norm_type=cv2.NORM_MINMAX, dtype=cv2.CV_32F)

What does += mean in Python?

a += b is essentially the same as a = a + b, except that:

  • + always returns a newly allocated object, but += should (but doesn't have to) modify the object in-place if it's mutable (e.g. list or dict, but int and str are immutable).

  • In a = a + b, a is evaluated twice.

  • Python: Simple Statements

    • A simple statement is comprised within a single logical line.

If this is the first time you encounter the += operator, you may wonder why it matters that it may modify the object in-place instead of building a new one. Here is an example:

# two variables referring to the same list
>>> list1 = []
>>> list2 = list1

# += modifies the object pointed to by list1 and list2
>>> list1 += [0]
>>> list1, list2
([0], [0])

# + creates a new, independent object
>>> list1 = []
>>> list2 = list1
>>> list1 = list1 + [0]
>>> list1, list2
([0], [])

pthread function from a class

This is a bit old question but a very common issue which many face. Following is a simple and elegant way to handle this by using std::thread

#include <iostream>
#include <utility>
#include <thread>
#include <chrono>

class foo
        void bar(int j)
            n = j;
            for (int i = 0; i < 5; ++i) {
                std::cout << "Child thread executing\n";
        int n = 0;

int main()
    int n = 5;
    foo f;
    std::thread class_thread(&foo::bar, &f, n); // t5 runs foo::bar() on object f
    std::cout << "Main Thread running as usual";
    std::cout << "Final value of foo::n is " << f.n << '\n';

Above code also takes care of passing argument to the thread function.

Refer std::thread document for more details.

How can I remove the outline around hyperlinks images?

I would bet most users aren't the type of user that use the keyboard as a navigation control. Is it then acceptable to annoy the majority of your users for a small group that prefers to use keyboard navigation? Short answer — depends on who your users are.

Also, I don't see this experience in the same way in Firefox and Safari. So this argument seems to be mostly for IE. It all really depends on your user base and their level of knowledge — how they use the site.

If you really want to know where you are and you are a keyboard user, you can always look at the status bar as you key through the site.

Construct pandas DataFrame from list of tuples of (row,col,values)

I submit that it is better to leave your data stacked as it is:

df = pandas.DataFrame(data, columns=['R_Number', 'C_Number', 'Avg', 'Std'])

# Possibly also this if these can always be the indexes:
# df = df.set_index(['R_Number', 'C_Number'])

Then it's a bit more intuitive to say

df.set_index(['R_Number', 'C_Number']).Avg.unstack(level=1)

This way it is implicit that you're seeking to reshape the averages, or the standard deviations. Whereas, just using pivot, it's purely based on column convention as to what semantic entity it is that you are reshaping.

CSS transition fade on hover

I recommend you to use an unordered list for your image gallery.

You should use my code unless you want the image to gain instantly 50% opacity after you hover out. You will have a smoother transition.

#photos li {
    opacity: .5;
    transition: opacity .5s ease-out;
    -moz-transition: opacity .5s ease-out;
    -webkit-transition: opacity .5s ease-out;
    -o-transition: opacity .5s ease-out;

#photos li:hover {
    opacity: 1;

Making a WinForms TextBox behave like your browser's address bar

It's a bit kludgey, but in your click event, use SendKeys.Send( "{HOME}+{END}" );.

LINQ query to select top five

The solution:

var list = (from t in ctn.Items
           where t.DeliverySelection == true && t.Delivery.SentForDelivery == null
           orderby t.Delivery.SubmissionDate
           select t).Take(5);

Checking if float is an integer

Keep in mind that most of the techniques here are valid presuming that round-off error due to prior calculations is not a factor. E.g. you could use roundf, like this:

float z = 1.0f;

if (roundf(z) == z) {
} else {

The problem with this and other similar techniques (such as ceilf, casting to long, etc.) is that, while they work great for whole number constants, they will fail if the number is a result of a calculation that was subject to floating-point round-off error. For example:

float z = powf(powf(3.0f, 0.05f), 20.0f);

if (roundf(z) == z) {
} else {

Prints "fraction", even though (31/20)20 should equal 3, because the actual calculation result ended up being 2.9999992847442626953125.

Any similar method, be it fmodf or whatever, is subject to this. In applications that perform complex or rounding-prone calculations, usually what you want to do is define some "tolerance" value for what constitutes a "whole number" (this goes for floating-point equality comparisons in general). We often call this tolerance epsilon. For example, lets say that we'll forgive the computer for up to +/- 0.00001 rounding error. Then, if we are testing z, we can choose an epsilon of 0.00001 and do:

if (fabsf(roundf(z) - z) <= 0.00001f) {
} else {

You don't really want to use ceilf here because e.g. ceilf(1.0000001) is 2 not 1, and ceilf(-1.99999999) is -1 not -2.

You could use rintf in place of roundf if you prefer.

Choose a tolerance value that is appropriate for your application (and yes, sometimes zero tolerance is appropriate). For more information, check out this article on comparing floating-point numbers.

What order are the Junit @Before/@After called?

If you turn things around, you can declare your base class abstract, and have descendants declare setUp and tearDown methods (without annotations) that are called in the base class' annotated setUp and tearDown methods.

What's the difference between Apache's Mesos and Google's Kubernetes

Mesos and Kubernetes can both be used to manage a cluster of machines and abstract away the hardware.

Mesos, by design, doesn't provide you with a scheduler (to decide where and when to run processes and what to do if the process fails), you can use something like Marathon or Chronos, or write your own.

Kubernetes will do scheduling for you out of the box, and can be used as a scheduler for Mesos (please correct me if I'm wrong here!) which is where you can use them together. Mesos can have multiple schedulers sharing the same cluster, so in theory you could run kubernetes and chronos together on the same hardware.

Super simplistically: if you want control over how your containers are scheduled, go for Mesos, otherwise Kubernetes rocks.

How do I import a .dmp file into Oracle?

imp system/system-password@SID file=directory-you-selected\FILE.dmp log=log-dir\oracle_load.log fromuser=infodba touser=infodba commit=Y

What is the best java image processing library/approach?

I cannot say that it is the "best" library, but I think you can try this: It is an open-source Java library, supporting generalized "smart" arrays and matrices with elements of different types (from 1 bit to 64-bit floating point), including 2D-, 3D- and multidimensional image processing and other algorithms, working with arrays and matrices. Unfortunately right now it consists not enough demo and examples, but, on the other hand, it contains a lot of JavaDocs. It lay in the base of commercial software (SIMAGIS) during several years, but now it is open-source.

how to open an URL in Swift3

All you need is:

guard let url = URL(string: "") else {
  return //be safe

if #available(iOS 10.0, *) {, options: [:], completionHandler: nil)
} else {

'Invalid update: invalid number of rows in section 0

In my case issue was that numberOfRowsInSection was returning similar number of rows after calling tableView.deleteRows(...).

Since this was the required behaviour in my case, I ended up calling tableView.reloadData() instead of tableView.deleteRows(...) in cases where numberOfRowsInSection will remain same after deleting a row.

Could not open input file: artisan

Just try and execute the command in directory where all laravel code resides. Happened with me too, I was trying to run the command in project's root folder, but the code was in a sub directory

Error:(1, 0) Plugin with id '' not found

I still got the error

 Could not find

Problem: jcenter() did not have the required libs

Solution: add google() as repo

buildscript {
    repositories {

    dependencies {

        classpath ""

Convert double to BigDecimal and set BigDecimal Precision

In Java 9 the following is deprecated:

BigDecimal.valueOf(d).setScale(2, BigDecimal.ROUND_HALF_UP);

instead use:

BigDecimal.valueOf(d).setScale(2, RoundingMode.HALF_UP);


    double d = 47.48111;

    System.out.println(BigDecimal.valueOf(d)); //Prints: 47.48111

    BigDecimal bigDecimal = BigDecimal.valueOf(d).setScale(2, RoundingMode.HALF_UP);
    System.out.println(bigDecimal); //Prints: 47.48

gcc-arm-linux-gnueabi command not found

You have installed a toolchain which was compiled for i686 on a box which is running an x86_64 userland.

Use an i686 VM.

How to make Bootstrap 4 cards the same height in card-columns?


Just add the height you want with CSS, example:

    height: 350px;

You will have to add your own CSS.

If you check the documentation, this is for Masonry style - the point of that is they are not all the same height.

Finding first and last index of some value in a list in Python

Python lists have the index() method, which you can use to find the position of the first occurrence of an item in a list. Note that list.index() raises ValueError when the item is not present in the list, so you may need to wrap it in try/except:

    idx = lst.index(value)
except ValueError:
    idx = None

To find the position of the last occurrence of an item in a list efficiently (i.e. without creating a reversed intermediate list) you can use this function:

def rindex(lst, value):
    for i, v in enumerate(reversed(lst)):
        if v == value:
            return len(lst) - i - 1  # return the index in the original list
    return None    

print(rindex([1, 2, 3], 3))     # 2
print(rindex([3, 2, 1, 3], 3))  # 3
print(rindex([3, 2, 1, 3], 4))  # None

Converting year and month ("yyyy-mm" format) to a date?

Using anytime package:


# [1] "2009-01-01"

How to center cell contents of a LaTeX table whose columns have fixed widths?

\usepackage{array} in the preamble

then this:

\begin{tabular}{| >{\centering\arraybackslash}m{1in} | >{\centering\arraybackslash}m{1in} |}

note that the "m" for fixed with column is provided by the array package, and will give you vertical centering (if you don't want this just go back to "p"

Remove a specific character using awk or sed

tr can be more concise for removing characters than sed or awk, especially when you want to remove different characters from a string.

Removing double quotes:

echo '"Hi"' | tr -d \"
# Produces Hi without quotes

Removing different kinds of brackets:

echo '[{Hi}]' | tr -d {}[]
# Produces Hi without brackets

-d stands for "delete".

Slide right to left?

You can define first the width of the element as 0, floating right, and then on the event that you are about to show it.. it would be like

$('#the_element_to_slide_from_right_left').animate({ width:'your desired width' }, 600);

Simple as that.

What is the best free SQL GUI for Linux for various DBMS systems

I'm sticking with DbVisualizer Free until something better comes along.

EDIT/UPDATE: been using lately, really enjoying this

More elegant way of declaring multiple variables at the same time

a, b, c, d, e, g, h, i, j = (True,)*9
f = False

Resource interpreted as Document but transferred with MIME type application/json warning in Chrome Developer Tools

This type of warnings are usually flagged because of the request HTTP headers. Specifically the Accept request header. The MDN documentation for HTTP headers states

The Accept request HTTP header advertises which content types, expressed as MIME types, the client is able to understand. Using content negotiation, the server then selects one of the proposals, uses it and informs the client of its choice with the Content-Type response header. Browsers set adequate values for this header depending of the context where the request is done....

application/json is probably not on the list of MIME types in the Accept header sent by the browser hence the warning.


Custom HTTP headers can only be sent programmatically via XMLHttpRequest or any of the js library wrappers implementing it.

Form Submit jQuery does not work

If you are doing form validation such as

type="submit" onsubmit="return validateForm(this)"

validateForm = function(form) {
if ($('input#company').val() === "" || $('input#company').val() === "Company")  {
        $('input#company').val("Company").css('color','red'); finalReturn = false; 
        $('input#company').on('mouseover',(function() { 
            finalReturn = true; 

    return finalReturn; 

Double check you are returning true. This seems simple but I had

var finalReturn = false;

When the form was correct it was not being corrected by validateForm and so not being submitted as finalReturn was still initialized to false instead of true. By the way, above code works nicely with address, city, state and so on.

How to form a correct MySQL connection string?

Here is an example:

MySqlConnection con = new MySqlConnection(

MySqlCommand cmd = new MySqlCommand(
    " INSERT Into Test (lat, long) VALUES ('"+OSGconv.deciLat+"','"+
    OSGconv.deciLon+"')", con);


How to add image for button in android?

You can create an ImageButton in your android activity_main.xml and which image you want to place in your button just paste that image in your drawable folder below is the sample code for your reference.



Create nice column output in python

Wow, only 17 answers. The zen of python says "There should be one-- and preferably only one --obvious way to do it."

So here is an 18th way to do it: The tabulate package supports a bunch of data types that it can display as tables, here is a simple example adapted from their docs:

from tabulate import tabulate

table = [["Sun",696000,1989100000],

print(tabulate(table, headers=["Planet","R (km)", "mass (x 10^29 kg)"]))

which outputs

Planet      R (km)    mass (x 10^29 kg)
--------  --------  -------------------
Sun         696000           1.9891e+09
Earth         6371        5973.6
Moon          1737          73.5
Mars          3390         641.85

Rounding up to next power of 2

next = pow(2, ceil(log(x)/log(2)));

This works by finding the number you'd have raise 2 by to get x (take the log of the number, and divide by the log of the desired base, see wikipedia for more). Then round that up with ceil to get the nearest whole number power.

This is a more general purpose (i.e. slower!) method than the bitwise methods linked elsewhere, but good to know the maths, eh?

Delete last commit in bitbucket

As others have said, usually you want to use hg backout or git revert. However, sometimes you really want to get rid of a commit.

First, you'll want to go to your repository's settings. Click on the Strip commits link.

Strip commits link in bitbucket settings

Enter the changeset ID for the changeset you want to destroy, and click Preview strip. That will let you see what kind of damage you're about to do before you do it. Then just click Confirm and your commit is no longer history. Make sure you tell all your collaborators what you've done, so they don't accidentally push the offending commit back.

What is a regular expression for a MAC Address?

This link might help you. You can use this : (([0-9A-Fa-f]{2}[-:]){5}[0-9A-Fa-f]{2})|(([0-9A-Fa-f]{4}\.){2}[0-9A-Fa-f]{4})

jquery can't get data attribute value

You can change the selector and data attributes as you wish!

 <select id="selectVehicle">
       <option value="1" data-year="2011">Mazda</option>
       <option value="2" data-year="2015">Honda</option>
       <option value="3" data-year="2008">Mercedes</option>
       <option value="4" data-year="2005">Toyota</option>

$("#selectVehicle").change(function () {

Here is the working example:

How to fix apt-get: command not found on AWS EC2?

I guess you are actually using Amazon Linux AMI 2013.03.1 instead of Ubuntu Server 12.x reason why you don't have apt-get tool installed.

Create unique constraint with null columns

You could create a unique index with a coalesce on the MenuId:

Favorites_UniqueFavorite ON Favorites
(UserId, COALESCE(MenuId, '00000000-0000-0000-0000-000000000000'), RecipeId);

You'd just need to pick a UUID for the COALESCE that will never occur in "real life". You'd probably never see a zero UUID in real life but you could add a CHECK constraint if you are paranoid (and since they really are out to get you...):

alter table Favorites
add constraint check
(MenuId <> '00000000-0000-0000-0000-000000000000')

Simple way to repeat a string

a straightforward one-line solution:
requires Java 8

Collections.nCopies( 3, "abc" ).stream().collect( Collectors.joining() );

Does Python have a package/module management system?

And just to provide a contrast, there's also pip.

sys.path different in Jupyter and Python - how to import own modules in Jupyter?

Suppose your project has the following structure and you want to do imports in the notebook.ipynb:


If you are running Jupyter inside a docker container without any virtualenv it might be useful to create Jupyter (ipython) config in your project folder:


Content of

c.InteractiveShellApp.exec_lines = [
    'import sys; sys.path.append("/app")'

Open the notebook and check it out:


['', '/usr/local/lib/', '/usr/local/lib/python3.6', '/usr/local/lib/python3.6/lib-dynload', '/usr/local/lib/python3.6/site-packages', '/usr/local/lib/python3.6/site-packages/IPython/extensions', '/root/.ipython', '/app']

Now you can do imports in your notebook without any sys.path appending in the cells:

from mypackage.mymodule import myfunc

Count the number of occurrences of each letter in string

Have checked that many of the answered are with static array, what if suppose I have special character in the string and want a solution with dynamic concept. There can be many other possible solutions, it is one of them.

here is the solutions with the Linked List.

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

struct Node { 
    char data; 
    int counter;
    struct Node* next; 

void printLinkList(struct Node* head)
    while (head != NULL) { 
        printf("\n%c occur %d", head->data, head->counter);
        head = head->next;

int main(void) {
    char *str = "!count all the occurances of character in string!";
    int i = 0;
    char tempChar;
    struct Node* head = NULL; 
    struct Node* node = NULL; 
    struct Node* first = NULL; 

    for(i = 0; i < strlen(str); i++)
        tempChar = str[i];

        head = first;

        if(head == NULL)
            node = (struct Node*)malloc(sizeof(struct Node));
            node->data = tempChar;
            node->counter = 1;
            node->next = NULL;

            if(first == NULL)
                first = node;
            while (head->next != NULL) { 
                if(head->data == tempChar)
                    head->counter = head->counter + 1;
                head = head->next;

            if(head->next == NULL)
                if(head->data == tempChar)
                    head->counter = head->counter + 1;
                    node = (struct Node*)malloc(sizeof(struct Node));
                    node->data = tempChar;
                    node->counter = 1;
                    node->next = NULL;
                    head->next = node;


    return 0;

jQuery append text inside of an existing paragraph tag

I have just discovered a way to append text and its working fine at least.

 var text = 'Put any text here';

You can change text according to your need.

Hope this helps.

Are table names in MySQL case sensitive?

  1. Locate the file at /etc/mysql/my.cnf

  2. Edit the file by adding the following lines:

  3. sudo /etc/init.d/mysql restart

  4. Run mysqladmin -u root -p variables | grep table to check that lower_case_table_names is 1 now

You might need to recreate these tables to make it work.

Sound alarm when code finishes

A bit more to your question.

I used gTTS package to generate audio from text and then play that audio using Playsound when I was learning webscraping and created a coursera downloader(only free courses).

text2speech = gTTS("Your course " + course_name +
                                " is downloaded to " + downloads + ". Check it fast.")"temp.mp3")
winsound.Beep(2500, 1000)

How can I get a character in a string by index?

Do you mean like this

int index = 2;
string s = "hello";

string also implements IEnumberable<char> so you can also enumerate it like this

foreach (char c in s)

UPDATE with CASE and IN - Oracle

"The list are variables/paramaters that is pre-defined as comma separated lists". Do you mean that your query is actually

UPDATE tab1   SET budgpost_gr1=     
CASE  WHEN (budgpost in ('1001,1012,50055'))  THEN 'BP_GR_A'   
      WHEN (budgpost in ('5,10,98,0'))  THEN 'BP_GR_B'  
      WHEN (budgpost in ('11,876,7976,67465'))     
      ELSE 'Missing' END`

If so, you need a function to take a string and parse it into a list of numbers.

create type tab_num is table of number;

create or replace function f_str_to_nums (i_str in varchar2) return tab_num is
  v_tab_num tab_num := tab_num();
  v_start   number := 1;
  v_end     number;
  v_delim   VARCHAR2(1) := ',';
  v_cnt     number(1) := 1;
  v_end := instr(i_str||v_delim,v_delim,1, v_start);
  WHILE v_end > 0 LOOP
    v_cnt := v_cnt + 1;
    v_tab_num(v_tab_num.count) := 
    v_start := v_end + 1;
    v_end := instr(i_str||v_delim,v_delim,v_start);
  RETURN v_tab_num;

Then you can use the function like so:

select column_id, 
   case when column_id in 
     (select column_value from table(f_str_to_nums('1,2,3,4'))) then 'red' 
   else 'blue' end
from  user_tab_columns
where table_name = 'EMP'

Flutter : Vertically center column

Try this one. It centers vertically and horizontally.

  child: Column(
    children: children,

How to capture a JFrame's close button click event?


also works. First create a JFrame called frame, then add this code underneath.

Maven won't run my Project : Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:exec

I solved this issue with right click on project -> Set as Main Project.

SQL Server 2008 - Login failed. The login is from an untrusted domain and cannot be used with Windows authentication

I was getting this error too, although my issue was that I kept switching between two corporate networks via my Virtual Machine, with different access credentials. I had to run the command prompt:

ipconfig /renew

After this my network issues were resolved and I could connect once again to SQL.

Retrieve only the queried element in an object array in MongoDB collection

Although the question was asked 9.6 years ago, this has been of immense help to numerous people, me being one of them. Thank you everyone for all your queries, hints and answers. Picking up from one of the answers here.. I found that the following method can also be used to project other fields in the parent document.This may be helpful to someone.

For the following document, the need was to find out if an employee (emp #7839) has his leave history set for the year 2020. Leave history is implemented as an embedded document within the parent Employee document.

db.employees.find( {"leave_history.calendar_year": 2020}, 
    {leave_history: {$elemMatch: {calendar_year: 2020}},empno:true,ename:true}).pretty()

        "_id" : ObjectId("5e907ad23997181dde06e8fc"),
        "empno" : 7839,
        "ename" : "KING",
        "mgrno" : 0,
        "hiredate" : "1990-05-09",
        "sal" : 100000,
        "deptno" : {
                "_id" : ObjectId("5e9065f53997181dde06e8f8")
        "username" : "none",
        "password" : "none",
        "is_admin" : "N",
        "is_approver" : "Y",
        "is_manager" : "Y",
        "user_role" : "AP",
        "admin_approval_received" : "Y",
        "active" : "Y",
        "created_date" : "2020-04-10",
        "updated_date" : "2020-04-10",
        "application_usage_log" : [
                        "logged_in_as" : "AP",
                        "log_in_date" : "2020-04-10"
                        "logged_in_as" : "EM",
                        "log_in_date" : ISODate("2020-04-16T07:28:11.959Z")
        "leave_history" : [
                        "calendar_year" : 2020,
                        "pl_used" : 0,
                        "cl_used" : 0,
                        "sl_used" : 0
                        "calendar_year" : 2021,
                        "pl_used" : 0,
                        "cl_used" : 0,
                        "sl_used" : 0

Getting current directory in VBScript

Your line

Directory = CurrentDirectory\attribute.exe

does not match any feature I have encountered in a vbscript instruction manual. The following works for me, tho not sure what/where you expect "attribute.exe" to reside.

dim fso
dim curDir
dim WinScriptHost
set fso = CreateObject("Scripting.FileSystemObject")
curDir = fso.GetAbsolutePathName(".")
set fso = nothing
Set WinScriptHost = CreateObject("WScript.Shell")
WinScriptHost.Run curDir & "\testme.bat", 1
set WinScriptHost = nothing

Position a CSS background image x pixels from the right?

The most appropriate answer is the new four-value syntax for background-position, but until all browsers support it your best approach is a combination of earlier responses in the following order:

background: url(image.png) no-repeat 97% center; /* default, Android, Sf < 6 */
background-position: -webkit-calc(100% - 10px) center; /* Sf 6 */
background-position: right 10px center; /* Cr 25+, FF 13+, IE 9+, Op 10.5+ */

Split string into array

You can try this way:

let entry = prompt("Enter your name") 
let entryArray = entry.split('')

here is fiddle

How to properly set the 100% DIV height to match document/window height?

Use #element{ height:100vh}

This will set the height of the #element to 100% of viewport. Hope this helps.

How to properly exit a C# application?

Do you do:


in your Main()?

I found it a very easy way to kill the application when the form is closed.

How to use Apple's new San Francisco font on a webpage

try this out:

font-family: 'SF Pro Text',-apple-system,BlinkMacSystemFont,Roboto,'Segoe UI',Helvetica,Arial,sans-serif,'Apple Color Emoji','Segoe UI Emoji','Segoe UI Symbol';

It worked for me. ;) Do upvote if it works.

How can I compare two lists in python and return matches

you can | for set union and & for set intersection.
for example:



curly braces in the answer.

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

Usually I do this:

       <img src='1.jpg' align='left' />
       Text Here

How can I tell where mongoDB is storing data? (its not in the default /data/db!)

Actually, the default directory where the mongod instance stores its data is

/data/db on Linux and OS X,

\data\db on Windows

To check the same, you can look for dbPath settings in mongodb configuration file.

  • On Linux, the location is /etc/mongod.conf, if you have used package manager to install MongoDB. Run the following command to check the specified directory:
    grep dbpath /etc/mongodb.conf
  • On Windows, the location is <install directory>/bin/mongod.cfg. Open mongod.cfg file and check for dbPath option.
  • On macOS, the location is /usr/local/etc/mongod.conf when installing from MongoDB’s official Homebrew tap.

The default mongod.conf configuration file included with package manager installations uses the following platform-specific default values for storage.dbPath:

|         Platform         | Package Manager | Default storage.dbPath |
| RHEL / CentOS and Amazon | yum             | /var/lib/mongo         |
| SUSE                     | zypper          | /var/lib/mongo         |
| Ubuntu and Debian        | apt             | /var/lib/mongodb       |
| macOS                    | brew            | /usr/local/var/mongodb |

The storage.dbPath setting in the configuration file is available only for mongod.

The Linux package init scripts do not expect storage.dbPath to change from the defaults. If you use the Linux packages and change storage.dbPath, you will have to use your own init scripts and disable the built-in scripts.


How to get single value of List<object>

You can access the fields by indexing the object array:

foreach (object[] item in selectedValues)
  idTextBox.Text = item[0];
  titleTextBox.Text = item[1];
  contentTextBox.Text = item[2];

That said, you'd be better off storing the fields in a small class of your own if the number of items is not dynamic:

public class MyObject
    public int Id { get; set; }
    public string Title { get; set; }
    public string Content { get; set; }

Then you can do:

foreach (MyObject item in selectedValues)
  idTextBox.Text = item.Id;
  titleTextBox.Text = item.Title;
  contentTextBox.Text = item.Content;

Laravel Eloquent - Get one Row

Laravel 5.2

$sql = "SELECT * FROM users WHERE email = $email";

$user = collect(\User::select($sql))->first();


$user = User::table('users')->where('email', $email)->pluck();

How to delete a specific line in a file?

This is a "fork" from @Lother's answer (which I believe that should be considered the right answer).

For a file like this:

$ cat file.txt 
1: october rust
2: november rain
3: december snow

This fork from Lother's solution works fine:


with open("file.txt","r+") as f:
    new_f = f.readlines()
    for line in new_f:
        if "snow" not in line:


  • with open, which discard the usage of f.close()
  • more clearer if/else for evaluating if string is not present in the current line

How to connect access database in c#

Try this code,

public void ConnectToAccess()
    System.Data.OleDb.OleDbConnection conn = new 
    // TODO: Modify the connection string and include any
    // additional required properties for your database.
    conn.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;" +
        @"Data source= C:\Documents and Settings\username\" +
        @"My Documents\AccessFile.mdb";
        // Insert code to process data.
        catch (Exception ex)
        MessageBox.Show("Failed to connect to data source");

Convert binary to ASCII and vice versa

I'm not sure how you think you can do it other than character-by-character -- it's inherently a character-by-character operation. There is certainly code out there to do this for you, but there is no "simpler" way than doing it character-by-character.

First, you need to strip the 0b prefix, and left-zero-pad the string so it's length is divisible by 8, to make dividing the bitstring up into characters easy:

bitstring = bitstring[2:]
bitstring = -len(bitstring) % 8 * '0' + bitstring

Then you divide the string up into blocks of eight binary digits, convert them to ASCII characters, and join them back into a string:

string_blocks = (bitstring[i:i+8] for i in range(0, len(bitstring), 8))
string = ''.join(chr(int(char, 2)) for char in string_blocks)

If you actually want to treat it as a number, you still have to account for the fact that the leftmost character will be at most seven digits long if you want to go left-to-right instead of right-to-left.

How to declare array of zeros in python (or an array of a certain size)

use numpy

import numpy
zarray = numpy.zeros(100)

And then use the Histogram library function

Draw radius around a point in Google map

I have just written a blog article that addresses exactly this, which you may find useful:

Basically, you need to create a GGroundOverlay with the correct GLatLngBounds. The tricky bit is in working out the southwest corner coordinate and the northeast corner coordinate of this imaginery square (the GLatLngBounds) bounding this circle, based on the desired radius. The math is quite complicated, but you can just refer to getDestLatLng function in the blog. The rest should be pretty straightforward.

Where is the documentation for the values() method of Enum?

The method is implicitly defined (i.e. generated by the compiler).

From the JLS:

In addition, if E is the name of an enum type, then that type has the following implicitly declared static methods:

* Returns an array containing the constants of this enum 
* type, in the order they're declared.  This method may be
* used to iterate over the constants as follows:
*    for(E c : E.values())
*        System.out.println(c);
* @return an array containing the constants of this enum 
* type, in the order they're declared
public static E[] values();

* Returns the enum constant of this type with the specified
* name.
* The string must match exactly an identifier used to declare
* an enum constant in this type.  (Extraneous whitespace 
* characters are not permitted.)
* @return the enum constant with the specified name
* @throws IllegalArgumentException if this enum type has no
* constant with the specified name
public static E valueOf(String name);

Tensorflow: Using Adam optimizer

I was having a similar problem. (No problems training with GradientDescent optimizer, but error raised when using to Adam Optimizer, or any other optimizer with its own variables)

Changing to an interactive session solved this problem for me.

sess = tf.Session()


sess = tf.InteractiveSession()

How to pause a vbscript execution?

With 'Enter' is better use ReadLine() or Read(2), because key 'Enter' generate 2 symbols. If user enter any text next Pause() also wil be skipped even with Read(2). So ReadLine() is better:

Sub Pause()
    WScript.Echo ("Press Enter to continue")
    z = WScript.StdIn.ReadLine()
End Sub

More examples look in

Difference between parameter and argument

Arguments and parameters are different in that parameters are used to different values in the program and The arguments are passed the same value in the program so they are used in c++. But no difference in c. It is the same for arguments and parameters in c.

Saving a Numpy array as an image

for saving a numpy array as image, U have several choices:

1) best of other: OpenCV

 import cv2   
 cv2.imwrite('file name with extension(like .jpg)', numpy_array)

2) Matplotlib

  from matplotlib import pyplot as plt
  plt.imsave('file name with extension(like .jpg)', numpy_array)

3) PIL

  from PIL import Image
  image = Image.fromarray(numpy_array)'file name with extension(like .jpg)')

4) ...

Cannot assign requested address - possible causes?

It turns out that the problem really was that the address was busy - the busyness was caused by some other problems in how we are handling network communications. Your inputs have helped me figure this out. Thank you.

EDIT: to be specific, the problems in handling our network communications were that these status updates would be constantly re-sent if the first failed. It was only a matter of time until we had every distributed slave trying to send its status update at the same time, which was over-saturating our network.

Install MySQL on Ubuntu without a password prompt

sudo debconf-set-selections <<< 'mysql-server mysql-server/root_password password your_password'
sudo debconf-set-selections <<< 'mysql-server mysql-server/root_password_again password your_password'
sudo apt-get -y install mysql-server

For specific versions, such as mysql-server-5.6, you'll need to specify the version in like this:

sudo debconf-set-selections <<< 'mysql-server-5.6 mysql-server/root_password password your_password'
sudo debconf-set-selections <<< 'mysql-server-5.6 mysql-server/root_password_again password your_password'
sudo apt-get -y install mysql-server-5.6

For mysql-community-server, the keys are slightly different:

sudo debconf-set-selections <<< 'mysql-community-server mysql-community-server/root-pass password your_password'
sudo debconf-set-selections <<< 'mysql-community-server mysql-community-server/re-root-pass password your_password'
sudo apt-get -y install mysql-community-server

Replace your_password with the desired root password. (it seems your_password can also be left blank for a blank root password.)

If your shell doesn't support here-strings (zsh, ksh93 and bash support them), use:

echo ... | sudo debconf-set-selections 

tsql returning a table from a function or store procedure

You don't need (shouldn't use) a function as far as I can tell. The stored procedure will return tabular data from any SELECT statements you include that return tabular data.

A stored proc does not use RETURN statements.


 SELECT stuff INTO #temptbl1


 SELECT columns FROM #temptbln

Are static class variables possible in Python?

When define some member variable outside any member method, the variable can be either static or non-static depending on how the variable is expressed.

  • CLASSNAME.var is static variable
  • INSTANCENAME.var is not static variable.
  • self.var inside class is not static variable.
  • var inside the class member function is not defined.

For example:


class A:

    def printvar(self):
        print "self.var is %d" % self.var
        print "A.var is %d" % A.var

    a = A()
    a.var = 2

    A.var = 3

The results are

self.var is 2
A.var is 1
self.var is 2
A.var is 3

@RequestBody and @ResponseBody annotations in Spring

package com.programmingfree.springshop.controller;

import java.util.List;

import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.programmingfree.springshop.dao.UserShop;
import com.programmingfree.springshop.domain.User;

public class SpringShopController {

 UserShop userShop=new UserShop();

 @RequestMapping(value = "/{id}", method = RequestMethod.GET,headers="Accept=application/json")
 public User getUser(@PathVariable int id) {
  User user=userShop.getUserById(id);
  return user;

 @RequestMapping(method = RequestMethod.GET,headers="Accept=application/json")
 public List<User> getAllUsers() {
  List<User> users=userShop.getAllUsers();
  return users;


In the above example they going to display all user and particular id details now I want to use both id and name,

1) localhost:8093/plejson/shop/user <---this link will display all user details
2) localhost:8093/plejson/shop/user/11 <----if i use 11 in link means, it will display particular user 11 details

now I want to use both id and name

localhost:8093/plejson/shop/user/11/raju <-----------------like this it means we can use any one in this please help me out.....

Add custom message to thrown exception while maintaining stack trace in Java

Following code is a simple example that worked for me.Let me call the function main as parent function and divide as child function.
Basically i am throwing a new exception with my custom message (for the parent's call) if an exception occurs in child function by catching the Exception in the child first.

class Main {
    public static void main(String args[]) {
            long ans=divide(0);
        catch(Exception e){
            System.out.println("got exception:"+e.getMessage());


    public static long divide(int num) throws Exception{
        long x=-1;
        try {
        catch (Exception e){
            throw new Exception("Error occured in divide for number:"+num+"Error:"+e.getMessage());
        return x;

the last line return x will not run if error occurs somewhere in between.

Is there a command for formatting HTML in the Atom editor?

You can add atom beauty package for formatting text in atom..

file --> setting --> Install

then you type atom-beautify in search area.

then click Package button.. select atom beuty and install it.

next you can format your text using (Alt + ctrl + b) or right click and select beautify editor contents

How to recursively list all the files in a directory in C#?

In Framework 2.0 you can use (It list files of root folder, it's best the most popular answer):

static void DirSearch(string dir)
        foreach (string f in Directory.GetFiles(dir))
        foreach (string d in Directory.GetDirectories(dir))

    catch (System.Exception ex)

Relative Paths in Javascript in an external file

I used pekka's pattern. I think yet another pattern.

<script src="<% = Url.Content("~/Site/Scripts/myjsfile.js") %>?root=<% = Page.ResolveUrl("~/Site/images") %>">

and parsed querystring in myjsfile.js.

Plugins | jQuery Plugins

Function return value in PowerShell

The existing answers are correct, but sometimes you aren't actually returning something explicitly with a Write-Output or a return, yet there is some mystery value in the function results. This could be the output of a builtin function like New-Item

PS C:\temp> function ContrivedFolderMakerFunction {
>>    $folderName = [DateTime]::Now.ToFileTime()
>>    $folderPath = Join-Path -Path . -ChildPath $folderName
>>    New-Item -Path $folderPath -ItemType Directory
>>    return $true
>> }
PS C:\temp> $result = ContrivedFolderMakerFunction
PS C:\temp> $result

    Directory: C:\temp

Mode                LastWriteTime         Length Name
----                -------------         ------ ----
d-----         2/9/2020   4:32 PM                132257575335253136

All that extra noise of the directory creation is being collected and emitted in the output. The easy way to mitigate this is to add | Out-Null to the end of the New-Item statement, or you can assign the result to a variable and just not use that variable. It would look like this...

PS C:\temp> function ContrivedFolderMakerFunction {
>>    $folderName = [DateTime]::Now.ToFileTime()
>>    $folderPath = Join-Path -Path . -ChildPath $folderName
>>    New-Item -Path $folderPath -ItemType Directory | Out-Null
>>    # -or-
>>    $throwaway = New-Item -Path $folderPath -ItemType Directory 
>>    return $true
>> }
PS C:\temp> $result = ContrivedFolderMakerFunction
PS C:\temp> $result

New-Item is probably the more famous of these, but others include all of the StringBuilder.Append*() methods, as well as the SqlDataAdapter.Fill() method.

Java: Multiple class declarations in one file

Just FYI, if you are using Java 11+, there is an exception to this rule: if you run your java file directly (without compilation). In this mode, there is no restriction on a single public class per file. However, the class with the main method must be the first one in the file. has not been called yet

I had the same problem... my problem was that I was closing my quartz window after plot(x,y). Once I kept it open, the lines that previously resulted in errors just added things to my plot (like they were supposed to). Hopefully this might help some people who arrive at this page.

Android Studio: Add jar as library?

You can do this with two options.

first simple way.

Copy the .jar file to clipboard then add it to libs folder. To see libs folder in the project, choose the project from combobox above the folders.

then right click on the .jar file and click add as a library then choose a module then ok. You can see the .jar file in build.gradle file within dependencies block.

 dependencies {
        implementation fileTree(dir: 'libs', include: ['*.jar'])
        implementation ''
        implementation project(':okhttp-2.0.0')
        implementation ''

Second way is that: We can add a .jar file to a module by importing this .jar file as a .jar module then add this module to any module we want.

import module ---> choose your .jar file --> than import as a .jar -- enter image description here

Then CTRL+ALT+SHIFT+S --> project sturure -->choose the module you want ato add a jar -->Dependencendies --> Module Dependency. build.gradle of the module will updated automatically. enter image description here

git stash apply version

If one is on a Windows machine and in PowerShell, one needs to quote the argument such as:

git stash apply "stash@{0}"

...or to apply the changes and remove from the stash:

git stash pop "stash@{0}"

Otherwise without the quotes you might get this error:

fatal: ambiguous argument 'stash@': unknown revision or path not in the working tree.

Multiple Image Upload PHP form with one input

Multipal image uplode with other taBLE $sql1 = "INSERT INTO event(title) VALUES('$title')";

        $result1 = mysqli_query($connection,$sql1) or die(mysqli_error($connection));
        $lastid= $connection->insert_id;
        foreach ($_FILES["file"]["error"] as $key => $error) {
            if ($error == UPLOAD_ERR_OK ){
                $name = $lastid.$_FILES['file']['name'][$key];
                $target_dir = "photo/";
                $sql2 = "INSERT INTO photos(image,eventid) VALUES ('".$target_dir.$name."','".$lastid."')";
                $result2 = mysqli_query($connection,$sql2) or die(mysqli_error($connection));

And how to fetch

$query = "SELECT * FROM event ";
$result = mysqli_query($connection,$query) or die(mysqli_error());

  if($result->num_rows > 0) {
      while($r = mysqli_fetch_assoc($result)){
        $eventid= $r['id'];
        $sqli="select id,image from photos where eventid='".$eventid."'";
        $image_json_array = array();
        while($row = mysqli_fetch_assoc($resulti)){
            $image_id = $row['id'];
            $image_name = $row['image'];
            $image_json_array[] = array("id"=>$image_id,"name"=>$image_name);
        $msg1[] = array ("imagelist" => $image_json_array);


in ajax $(document).ready(function(){ $('#addCAT').validate({ rules:{name:required:true}submitHandler:function(form){var formurl = $(form).attr('action'); $.ajax({ url: formurl,type: "POST",data: new FormData(form),cache: false,processData: false,contentType: false,success: function(data) {window.location.href="{{ url('admin/listcategory')}}";}}); } })})

How do I save a String to a text file using Java?

You can use the ArrayList to put all the contents of the TextArea for exemple, and send as parameter by calling the save, as the writer just wrote string lines, then we use the "for" line by line to write our ArrayList in the end we will be content TextArea in txt file. if something does not make sense, I'm sorry is google translator and I who do not speak English.

Watch the Windows Notepad, it does not always jump lines, and shows all in one line, use Wordpad ok.

private void SaveActionPerformed(java.awt.event.ActionEvent evt) {

    String NameFile = Name.getText();
    ArrayList< String > Text = new ArrayList< String >();


    SaveFile(NameFile, Text);

public void SaveFile(String name, ArrayList< String> message) {

    path = "C:\\Users\\Paulo Brito\\Desktop\\" + name + ".txt";

    File file1 = new File(path);

    try {

        if (!file1.exists()) {


        File[] files = file1.listFiles();

        FileWriter fw = new FileWriter(file1, true);

        BufferedWriter bw = new BufferedWriter(fw);

        for (int i = 0; i < message.size(); i++) {



        FileReader fr = new FileReader(file1);

        BufferedReader br = new BufferedReader(fr);

        fw = new FileWriter(file1, true);

        bw = new BufferedWriter(fw);

        while (br.ready()) {

            String line = br.readLine();




    } catch (IOException ex) {
        JOptionPane.showMessageDialog(null, "Error in" + ex);     

What is the best way to auto-generate INSERT statements for a SQL Server table?

There are many good scripts above for generating insert statements, but I attempted one of my own to make it as user friendly as possible and to also be able to do UPDATE statements. + package the result ready for .sql files that can be stored by date.

It takes as input your normal SELECT statement with WHERE clause, then outputs a list of Insert statements and update statements. Together they form a sort of IF NOT EXISTS () INSERT ELSE UPDATE It is handy too when there are non-updatable columns that need exclusion from the final INSERT/UPDATE statement.

Another thing that below script can do is: it can even handle INNER JOINs with other tables as input statement for the stored proc. It can be handy as a poor man's Release management tool that sits right at your finger tips where you are typing the sql SELECT statements all day.

original post : Generate UPDATE statement in SQL Server for specific table

CREATE PROCEDURE [dbo].[sp_generate_updates] (
    @fullquery              nvarchar(max) = '',
    @ignore_field_input     nvarchar(MAX) = '',
    @PK_COLUMN_NAME         nvarchar(MAX) = ''

-- For Standard USAGE: (where clause is mandatory)
                EXEC [sp_generate_updates] 'select * from dbo.mytable where mytext=''1''  ' 
                EXEC [sp_generate_updates] "select * from dbo.mytable where mytext='1'    "

-- For ignoring specific columns  (to ignore in the UPDATE and INSERT SQL statement) 
                EXEC [sp_generate_updates] 'select * from dbo.mytable where 1=1  ' , 'Column01,Column02'

-- For just updates without insert statement (replace the * )
                EXEC [sp_generate_updates] 'select Column01, Column02 from dbo.mytable where 1=1  ' 

-- For tables without a primary key: construct the key in the third variable
                EXEC [sp_generate_updates] 'select * from dbo.mytable where 1=1  '  ,'','your_chosen_primary_key_Col1,key_Col2'

-- For complex updates with JOINED tables 
                EXEC [sp_generate_updates] 'select o1.Name,  o1.category, '_hello_world' as #name 
                                            from overnightsetting o1 
                                            inner join overnightsetting o2  on  
                                            where like '%appserver%' 
                (REMARK about above:   the use of # in front of a column name (so #abc) can do an update of that columname (abc) with any column from an inner joined table where you use the alias #abc )

-------------README for the deeper interested person:
            Goal of the Stored PROCEDURE is to get updates from simple SQL SELECT statements. It is made ot be simple but fast and powerfull. As always => power is nothing without control, so check before you execute.
            Its power sits also in the fact that you can make insert statements, so combined gives you a  "IF NOT EXISTS()  INSERT "   capability. 

            The scripts work were there are primary keys or identity columns on table you want to update (/ or make inserts for).
            It will also works when no primary keys / identity column exist(s) and you define them yourselve. But then be carefull (duplicate hits can occur). When the table has a primary key it will always be used.
            The script works with a real  temporary table, made on the fly   (APPROPRIATE RIGHTS needed), to put the values inside from the script, then add 3 columns for constructing the "insert into tableX (...) values ()" ,  and the 2 update statement.
            We work with temporary structures like   "where columnname = {Columnname}" and then later do the update on that temptable for the columns values found on that same line.
                    example  "where columnname = {Columnname}"  for birthdate becomes   "where birthdate = {birthdate}" an then we find the birthdate value on that line inside the temp table.
            So then the statement becomes  "where birthdate = {19800417}"
            Enjoy releasing scripts as of now...                                        by  Pieter van Nederkassel  - freeware "CC BY-SA" (+use at own risk)
IF OBJECT_ID('tempdb..#ignore','U') IS NOT NULL     DROP TABLE #ignore
DECLARE @stringsplit_table               TABLE (col nvarchar(255), dtype  nvarchar(255)) -- table to store the primary keys or identity key
DECLARE @PK_condition                    nvarchar(512), -- placeholder for WHERE pk_field1 = pk_value1 AND pk_field2 = pk_value2 AND ...
        @pkstring                        NVARCHAR(512),  -- sting to store the primary keys or the idendity key
        @table_name                      nvarchar(512), -- (left) table name, including schema
        @table_N_where_clause            nvarchar(max), -- tablename 
        @table_alias                     nvarchar(512), -- holds the (left) table alias if one available, else @table_name
        @table_schema                    NVARCHAR(30),  -- schema of @table_name
        @update_list1                    NVARCHAR(MAX), -- placeholder for SET fields section of update
        @update_list2                    NVARCHAR(MAX), -- placeholder for SET fields section of update value comming from other tables in the join, other than the main table to update => updateof base table possible with inner join
        @list_all_cols                   BIT = 0,       -- placeholder for values for the insert into table VALUES command
        @select_list                     NVARCHAR(MAX), -- placeholder for SELECT fields of (left) table
        @COLUMN_NAME                     NVARCHAR(255), -- will hold column names of the (left) table
        @sql                             NVARCHAR(MAX), -- sql statement variable
        @getdate                         NVARCHAR(17),  -- transform getdate() to YYYYMMDDHHMMSSMMM
        @tmp_table                       NVARCHAR(255), -- will hold the name of a physical temp table
        @pk_separator                    NVARCHAR(1),   -- separator used in @PK_COLUMN_NAME if provided (only checking obvious ones ,;|-)
        @COLUMN_NAME_DATA_TYPE           NVARCHAR(100), -- needed for insert statements to convert to right text string
        @own_pk                          BIT = 0        -- check if table has PK (0) or if provided PK will be used (1)

set @ignore_field_input=replace(replace(replace(@ignore_field_input,' ',''),'[',''),']','')
set @PK_COLUMN_NAME=    replace(replace(replace(@PK_COLUMN_NAME,    ' ',''),'[',''),']','')

-- first we remove all linefeeds from the user query
set @fullquery=replace(replace(replace(@fullquery,char(10),''),char(13),' '),'  ',' ')
set @table_N_where_clause=@fullquery
if charindex ('order by' , @table_N_where_clause) > 0
if @PK_COLUMN_NAME <> ''
    select ' WARNING:        IF you select your own primary keys, make double sure before doing the update statements below!! '
--print @table_N_where_clause
if charindex ('select ' , @table_N_where_clause) = 0
    set @table_N_where_clause= 'select * from ' + @table_N_where_clause
if charindex ('select ' , @table_N_where_clause) > 0
    exec (@table_N_where_clause)

set @table_N_where_clause=rtrim(ltrim(substring(@table_N_where_clause,CHARINDEX(' from ', @table_N_where_clause )+6, 4000)))
--print @table_N_where_clause 
set @table_name=left(@table_N_where_clause,CHARINDEX(' ', @table_N_where_clause )-1)

IF CHARINDEX('where ', @table_N_where_clause) > 0             SELECT @table_alias = LTRIM(RTRIM(REPLACE(REPLACE(SUBSTRING(@table_N_where_clause,1, CHARINDEX('where ', @table_N_where_clause )-1),'(nolock)',''),@table_name,'')))
IF CHARINDEX('join ',  @table_alias) > 0                      SELECT @table_alias = SUBSTRING(@table_alias, 1, CHARINDEX(' ', @table_alias)-1) -- until next space
IF LEN(@table_alias) = 0                                      SELECT @table_alias = @table_name
IF (charindex (' *' , @fullquery) > 0 or charindex (@table_alias+'.*' , @fullquery) > 0 )     set @list_all_cols=1
       print @fullquery     
       print @table_alias
       print @table_N_where_clause
       print @table_name

-- Prepare PK condition
        SELECT @table_schema = CASE WHEN CHARINDEX('.',@table_name) > 0 THEN LEFT(@table_name, CHARINDEX('.',@table_name)-1) ELSE 'dbo' END

        SELECT @PK_condition = ISNULL(@PK_condition + ' AND ', '') + QUOTENAME('pk_'+COLUMN_NAME) + ' = ' + QUOTENAME('pk_'+COLUMN_NAME,'{')
        AND TABLE_NAME = REPLACE(@table_name,@table_schema+'.','') 
        AND TABLE_SCHEMA = @table_schema

        SELECT @pkstring = ISNULL(@pkstring + ', ', '') + @table_alias + '.' + QUOTENAME(COLUMN_NAME) + ' AS pk_' + COLUMN_NAME
        AND i1.TABLE_NAME = REPLACE(@table_name,@table_schema+'.','') 
        AND i1.TABLE_SCHEMA = @table_schema

            -- if no primary keys exist then we try for identity columns
                IF @PK_condition is null SELECT @PK_condition = ISNULL(@PK_condition + ' AND ', '') + QUOTENAME('pk_'+COLUMN_NAME) + ' = ' + QUOTENAME('pk_'+COLUMN_NAME,'{')
                WHERE COLUMNPROPERTY(object_id(TABLE_SCHEMA+'.'+TABLE_NAME), COLUMN_NAME, 'IsIdentity') = 1 
                AND TABLE_NAME = REPLACE(@table_name,@table_schema+'.','') 
                AND TABLE_SCHEMA = @table_schema

                IF @pkstring is null SELECT @pkstring = ISNULL(@pkstring + ', ', '') + @table_alias + '.' + QUOTENAME(COLUMN_NAME) + ' AS pk_' + COLUMN_NAME
                WHERE COLUMNPROPERTY(object_id(TABLE_SCHEMA+'.'+TABLE_NAME), COLUMN_NAME, 'IsIdentity') = 1 
                AND TABLE_NAME = REPLACE(@table_name,@table_schema+'.','') 
                AND TABLE_SCHEMA = @table_schema
-- Same but in form of a table

        INSERT INTO @stringsplit_table
        SELECT 'pk_'+i1.COLUMN_NAME as col, i2.DATA_TYPE as dtype
        inner join INFORMATION_SCHEMA.COLUMNS i2
        AND i1.TABLE_NAME = REPLACE(@table_name,@table_schema+'.','') 
        AND i1.TABLE_SCHEMA = @table_schema

                -- if no primary keys exist then we try for identity columns
                IF 0=(select count(*) from @stringsplit_table) INSERT INTO @stringsplit_table
                SELECT 'pk_'+i2.COLUMN_NAME as col, i2.DATA_TYPE as dtype
                WHERE COLUMNPROPERTY(object_id(i2.TABLE_SCHEMA+'.'+i2.TABLE_NAME), i2.COLUMN_NAME, 'IsIdentity') = 1 
                AND i2.TABLE_NAME = REPLACE(@table_name,@table_schema+'.','') 
                AND i2.TABLE_SCHEMA = @table_schema

-- NOW handling the primary key given as parameter to the main batch

SELECT @pk_separator = ',' -- take this as default, we'll check lower if it's a different one
IF (@PK_condition IS NULL OR @PK_condition = '') AND @PK_COLUMN_NAME <> ''
        SELECT @pk_separator = ';'
        SELECT @pk_separator = '|'
        SELECT @pk_separator = '-'

    SELECT @PK_condition = NULL -- make sure to make it NULL, in case it was ''
    INSERT INTO @stringsplit_table
    SELECT LTRIM(RTRIM(x.value)) , 'datetime'  FROM STRING_SPLIT(@PK_COLUMN_NAME, @pk_separator) x  
    SELECT @PK_condition = ISNULL(@PK_condition + ' AND ', '') + QUOTENAME(x.col) + ' = ' + replace(QUOTENAME(x.col,'{'),'{','{pk_')
      FROM @stringsplit_table x

    SELECT @PK_COLUMN_NAME = NULL -- make sure to make it NULL, in case it was ''
    SELECT @PK_COLUMN_NAME = ISNULL(@PK_COLUMN_NAME + ', ', '') + QUOTENAME(x.col) + ' as pk_' + x.col
      FROM @stringsplit_table x
    --print 'pkcolumns  '+ isnull(@PK_COLUMN_NAME,'')
    update @stringsplit_table set col='pk_' + col
    SELECT @own_pk = 1
ELSE IF (@PK_condition IS NULL OR @PK_condition = '') AND @PK_COLUMN_NAME = ''
    RAISERROR('No Primary key or Identity column available on table. Add some columns as the third parameter when calling this SP to make your own temporary PK., also remove  [] from tablename',17,1)

-- IF there are no primary keys or an identity key in the table active, then use the given columns as a primary key

if isnull(@pkstring,'')   = ''  set    @pkstring  = @PK_COLUMN_NAME
IF ISNULL(@pkstring, '') <> ''  SELECT @fullquery = REPLACE(@fullquery, 'SELECT ','SELECT ' + @pkstring + ',' )
--print @pkstring

-- ignore fields for UPDATE STATEMENT (not ignored for the insert statement,  in iserts statement we ignore only identity Columns and the columns provided with the main stored proc )
-- Place here all fields that you know can not be converted to nvarchar() values correctly, an thus should not be scripted for updates)
-- for insert we will take these fields along, although they will be incorrectly represented!!!!!!!!!!!!!.
SELECT           ignore_field = 'uniqueidXXXX' INTO #ignore 
UNION ALL SELECT value FROM  string_split(@ignore_field_input,@pk_separator)

SELECT @getdate = REPLACE(REPLACE(REPLACE(REPLACE(CONVERT(NVARCHAR(30), GETDATE(), 121), '-', ''), ' ', ''), ':', ''), '.', '')
SELECT @tmp_table = 'Release_DATA__' + @getdate + '__' + REPLACE(@table_name,@table_schema+'.','') 

SET @sql = replace( @fullquery,  ' from ',  ' INTO ' + @tmp_table +' from ')
----print (@sql)
exec (@sql)

SELECT @sql = N'alter table ' + @tmp_table + N'  add update_stmt1  nvarchar(max), update_stmt2 nvarchar(max) , update_stmt3 nvarchar(max)'
EXEC (@sql)

-- Prepare update field list (only columns from the temp table are taken if they also exist in the base table to update)
SELECT @update_list1 = ISNULL(@update_list1 + ', ', '') + 
                      CASE WHEN C1.COLUMN_NAME = 'ModifiedBy' THEN '[ModifiedBy] = left(right(replace(CONVERT(VARCHAR(19),[Modified],121),''''-'''',''''''''),19) +''''-''''+right(SUSER_NAME(),30),50)'
                           WHEN C1.COLUMN_NAME = 'Modified' THEN '[Modified] = GETDATE()'
                           ELSE QUOTENAME(C1.COLUMN_NAME) + ' = ' + QUOTENAME(C1.COLUMN_NAME,'{')
on c1.COLUMN_NAME =c2.COLUMN_NAME and c2.TABLE_NAME = REPLACE(@table_name,@table_schema+'.','')  AND c2.TABLE_SCHEMA = @table_schema
WHERE c1.TABLE_NAME = @tmp_table --REPLACE(@table_name,@table_schema+'.','') 
AND QUOTENAME(c1.COLUMN_NAME) NOT IN (SELECT QUOTENAME(ignore_field) FROM #ignore) -- eliminate binary, image etc value here
AND COLUMNPROPERTY(object_id(c2.TABLE_SCHEMA+'.'+c2.TABLE_NAME), c2.COLUMN_NAME, 'IsIdentity') <> 1
                 WHERE 1 = 1
                   AND ku.TABLE_NAME = c2.TABLE_NAME
                   AND ku.TABLE_SCHEMA = c2.TABLE_SCHEMA
                   AND ku.COLUMN_NAME = c2.COLUMN_NAME
AND NOT EXISTS (SELECT 1 FROM @stringsplit_table x WHERE x.col = c2.COLUMN_NAME AND @own_pk = 1)

-- Prepare update field list  (here we only take columns that commence with a #, as this is our queue for doing the update that comes from an inner joined table)
SELECT @update_list2 = ISNULL(@update_list2 + ', ', '') +  QUOTENAME(replace( C1.COLUMN_NAME,'#','')) + ' = ' + QUOTENAME(C1.COLUMN_NAME,'{')
WHERE c1.TABLE_NAME = @tmp_table --AND c1.TABLE_SCHEMA = @table_schema
AND QUOTENAME(c1.COLUMN_NAME) NOT IN (SELECT QUOTENAME(ignore_field) FROM #ignore) -- eliminate binary, image etc value here
AND c1.COLUMN_NAME like '#%'

-- similar for select list, but take all fields
SELECT @select_list = ISNULL(@select_list + ', ', '') + QUOTENAME(COLUMN_NAME)
WHERE TABLE_NAME = REPLACE(@table_name,@table_schema+'.','') 
AND TABLE_SCHEMA = @table_schema
AND COLUMNPROPERTY(object_id(TABLE_SCHEMA+'.'+TABLE_NAME), COLUMN_NAME, 'IsIdentity') <> 1  -- Identity columns are filled automatically by MSSQL, not needed at Insert statement
AND QUOTENAME(c.COLUMN_NAME) NOT IN (SELECT QUOTENAME(ignore_field) FROM #ignore) -- eliminate binary, image etc value here

SELECT @PK_condition = REPLACE(@PK_condition, '[pk_', '[')
set @select_list='if not exists (select * from '+  REPLACE(@table_name,@table_schema+'.','') +'  where '+  @PK_condition +')  INSERT INTO '+ REPLACE(@table_name,@table_schema+'.','')   + '('+ @select_list  + ') VALUES (' + replace(replace(@select_list,'[','{'),']','}') + ')'
SELECT @sql = N'UPDATE ' + @tmp_table + ' set update_stmt1 = ''' + @select_list + '''' 
if @list_all_cols=1 EXEC (@sql)

--print 'select==========  ' + @select_list
--print 'update==========  ' + @update_list1

SELECT @sql = N'UPDATE ' + @tmp_table + N'
set update_stmt2 = CONVERT(NVARCHAR(MAX),''UPDATE ' + @table_name + 
                                          N' SET ' + @update_list1 + N''' + ''' +
                                          N' WHERE ' + @PK_condition + N''') ' 

EXEC (@sql)
--print @sql

SELECT @sql = N'UPDATE ' + @tmp_table + N'
set update_stmt3 = CONVERT(NVARCHAR(MAX),''UPDATE ' + @table_name + 
                                          N' SET ' + @update_list2 + N''' + ''' +
                                          N' WHERE ' + @PK_condition + N''') ' 

EXEC (@sql)
--print @sql

-- LOOPING OVER ALL base tables column for the INSERT INTO .... VALUES
    WHERE TABLE_NAME = (CASE WHEN @list_all_cols=0 THEN @tmp_table ELSE REPLACE(@table_name,@table_schema+'.','') END )
    AND TABLE_SCHEMA = @table_schema
    SELECT col, 'datetime' FROM @stringsplit_table

OPEN c_columns
    SELECT @sql = 
    CASE WHEN @COLUMN_NAME_DATA_TYPE IN ('char','varchar','nchar','nvarchar')
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt1 = REPLACE(update_stmt1, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL'')) ' 
        WHEN @COLUMN_NAME_DATA_TYPE IN ('float','real','money','smallmoney')
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt1 = REPLACE(update_stmt1, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'],126)),   '''''''','''''''''''') + '''''''', ''NULL'')) '
        WHEN @COLUMN_NAME_DATA_TYPE IN ('uniqueidentifier')
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt1 = REPLACE(update_stmt1, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL'')) ' 
        WHEN @COLUMN_NAME_DATA_TYPE IN ('text','ntext')
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt1 = REPLACE(update_stmt1, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL'')) ' 
        WHEN @COLUMN_NAME_DATA_TYPE IN ('xxxx','yyyy')
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt1 = REPLACE(update_stmt1, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL'')) ' 
        WHEN @COLUMN_NAME_DATA_TYPE IN ('binary','varbinary')
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt1 = REPLACE(update_stmt1, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL'')) ' 
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt1 = REPLACE(update_stmt1, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'],0)),     '''''''','''''''''''') + '''''''', ''NULL'')) ' 
        WHEN @COLUMN_NAME_DATA_TYPE IN ('datetime','smalldatetime')
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt1 = REPLACE(update_stmt1, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'],121)),   '''''''','''''''''''') + '''''''', ''NULL'')) '
                  N'UPDATE ' + @tmp_table + N' SET update_stmt1 = REPLACE(update_stmt1, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL'')) '
    ----PRINT @sql
    EXEC (@sql)
CLOSE c_columns
DEALLOCATE c_columns

--SELECT col FROM @stringsplit_table -- these are the primary keys

-- LOOPING OVER ALL temp tables column for the Update values
    WHERE TABLE_NAME =  @tmp_table --    AND TABLE_SCHEMA = @table_schema
    SELECT col, 'datetime' FROM @stringsplit_table

OPEN c_columns
    SELECT @sql = 
    CASE WHEN @COLUMN_NAME_DATA_TYPE IN ('char','varchar','nchar','nvarchar')
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt2 = REPLACE(update_stmt2, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL'')), update_stmt3 = REPLACE(update_stmt3, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL'')) ' 
        WHEN @COLUMN_NAME_DATA_TYPE IN ('float','real','money','smallmoney')
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt2 = REPLACE(update_stmt2, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'],126)),   '''''''','''''''''''') + '''''''', ''NULL'')), update_stmt3 = REPLACE(update_stmt3, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'],126)),   '''''''','''''''''''') + '''''''', ''NULL'')) '
        WHEN @COLUMN_NAME_DATA_TYPE IN ('uniqueidentifier')
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt2 = REPLACE(update_stmt2, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL'')), update_stmt3 = REPLACE(update_stmt3, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL''))  ' 
        WHEN @COLUMN_NAME_DATA_TYPE IN ('text','ntext')
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt2 = REPLACE(update_stmt2, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL'')), update_stmt3 = REPLACE(update_stmt3, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL''))  ' 
        WHEN @COLUMN_NAME_DATA_TYPE IN ('xxxx','yyyy')
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt2 = REPLACE(update_stmt2, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL'')), update_stmt3 = REPLACE(update_stmt3, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL''))  ' 
        WHEN @COLUMN_NAME_DATA_TYPE IN ('binary','varbinary')
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt2 = REPLACE(update_stmt2, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL'')), update_stmt3 = REPLACE(update_stmt3, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL''))  ' 
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt2 = REPLACE(update_stmt2, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'],0)),     '''''''','''''''''''') + '''''''', ''NULL'')), update_stmt3 = REPLACE(update_stmt3, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'],0)),     '''''''','''''''''''') + '''''''', ''NULL''))  ' 
        WHEN @COLUMN_NAME_DATA_TYPE IN ('datetime','smalldatetime')
            THEN  N'UPDATE ' + @tmp_table + N' SET update_stmt2 = REPLACE(update_stmt2, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'],121)),   '''''''','''''''''''') + '''''''', ''NULL'')), update_stmt3 = REPLACE(update_stmt3, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'],121)),   '''''''','''''''''''') + '''''''', ''NULL''))  ' 
                  N'UPDATE ' + @tmp_table + N' SET update_stmt2 = REPLACE(update_stmt2, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL'')), update_stmt3 = REPLACE(update_stmt3, ''{' + @COLUMN_NAME + N'}'', ISNULL('''''''' + REPLACE(RTRIM(CONVERT(NVARCHAR(MAX),[' + @COLUMN_NAME + N'])),       '''''''','''''''''''') + '''''''', ''NULL''))  ' 
    EXEC (@sql)
    ----print @sql
CLOSE c_columns
DEALLOCATE c_columns

SET @sql = 'Select * from  ' + @tmp_table + ';'
--exec (@sql)

SELECT @sql = N'
IF OBJECT_ID(''' + @tmp_table + N''', ''U'') IS NOT NULL
       SELECT   ''USE ' + DB_NAME()  + '''  as executelist 
              UNION ALL
       SELECT   ''GO ''  as executelist 
              UNION ALL
       SELECT   '' /*PRESCRIPT CHECK  */              ' + replace(@fullquery,'''','''''')+''' as executelist 
              UNION ALL
       SELECT update_stmt1 as executelist FROM ' + @tmp_table + N' where update_stmt1 is not null
              UNION ALL
       SELECT update_stmt2 as executelist FROM ' + @tmp_table + N' where update_stmt2 is not null
              UNION ALL
       SELECT isnull(update_stmt3, '' add more columns inn query please'')  as executelist FROM ' + @tmp_table + N' where update_stmt3 is not null
              UNION ALL
       SELECT ''--EXEC usp_AddInstalledScript 5, 5, 1, 1, 1, ''''' + @tmp_table + '.sql'''', 2 ''  as executelist
              UNION ALL 
       SELECT   '' /*VERIFY WITH:  */              ' + replace(@fullquery,'''','''''')+''' as executelist 
              UNION ALL
       SELECT ''-- SCRIPT LOCATION:      F:\CopyPaste\++Distributionpoint++\Release_Management\' + @tmp_table + '.sql''  as executelist   
exec (@sql)

SET @sql = 'DROP TABLE ' + @tmp_table + ';'
exec (@sql)

String to list in Python

Maybe like this:

list('abcdefgh') # ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']

Reading binary file and looping over each byte

Reading binary file in Python and looping over each byte

New in Python 3.5 is the pathlib module, which has a convenience method specifically to read in a file as bytes, allowing us to iterate over the bytes. I consider this a decent (if quick and dirty) answer:

import pathlib

for byte in pathlib.Path(path).read_bytes():

Interesting that this is the only answer to mention pathlib.

In Python 2, you probably would do this (as Vinay Sajip also suggests):

with open(path, 'b') as file:
    for byte in

In the case that the file may be too large to iterate over in-memory, you would chunk it, idiomatically, using the iter function with the callable, sentinel signature - the Python 2 version:

with open(path, 'b') as file:
    callable = lambda:
    sentinel = bytes() # or b''
    for chunk in iter(callable, sentinel): 
        for byte in chunk:

(Several other answers mention this, but few offer a sensible read size.)

Best practice for large files or buffered/interactive reading

Let's create a function to do this, including idiomatic uses of the standard library for Python 3.5+:

from pathlib import Path
from functools import partial
from io import DEFAULT_BUFFER_SIZE

def file_byte_iterator(path):
    """given a path, return an iterator over the file
    that lazily loads the file
    path = Path(path)
    with'rb') as file:
        reader = partial(file.read1, DEFAULT_BUFFER_SIZE)
        file_iterator = iter(reader, bytes())
        for chunk in file_iterator:
            yield from chunk

Note that we use file.read1. blocks until it gets all the bytes requested of it or EOF. file.read1 allows us to avoid blocking, and it can return more quickly because of this. No other answers mention this as well.

Demonstration of best practice usage:

Let's make a file with a megabyte (actually mebibyte) of pseudorandom data:

import random
import pathlib
path = 'pseudorandom_bytes'
pathobj = pathlib.Path(path)

  bytes(random.randint(0, 255) for _ in range(2**20)))

Now let's iterate over it and materialize it in memory:

>>> l = list(file_byte_iterator(path))
>>> len(l)

We can inspect any part of the data, for example, the last 100 and first 100 bytes:

>>> l[-100:]
[208, 5, 156, 186, 58, 107, 24, 12, 75, 15, 1, 252, 216, 183, 235, 6, 136, 50, 222, 218, 7, 65, 234, 129, 240, 195, 165, 215, 245, 201, 222, 95, 87, 71, 232, 235, 36, 224, 190, 185, 12, 40, 131, 54, 79, 93, 210, 6, 154, 184, 82, 222, 80, 141, 117, 110, 254, 82, 29, 166, 91, 42, 232, 72, 231, 235, 33, 180, 238, 29, 61, 250, 38, 86, 120, 38, 49, 141, 17, 190, 191, 107, 95, 223, 222, 162, 116, 153, 232, 85, 100, 97, 41, 61, 219, 233, 237, 55, 246, 181]
>>> l[:100]
[28, 172, 79, 126, 36, 99, 103, 191, 146, 225, 24, 48, 113, 187, 48, 185, 31, 142, 216, 187, 27, 146, 215, 61, 111, 218, 171, 4, 160, 250, 110, 51, 128, 106, 3, 10, 116, 123, 128, 31, 73, 152, 58, 49, 184, 223, 17, 176, 166, 195, 6, 35, 206, 206, 39, 231, 89, 249, 21, 112, 168, 4, 88, 169, 215, 132, 255, 168, 129, 127, 60, 252, 244, 160, 80, 155, 246, 147, 234, 227, 157, 137, 101, 84, 115, 103, 77, 44, 84, 134, 140, 77, 224, 176, 242, 254, 171, 115, 193, 29]

Don't iterate by lines for binary files

Don't do the following - this pulls a chunk of arbitrary size until it gets to a newline character - too slow when the chunks are too small, and possibly too large as well:

    with open(path, 'rb') as file:
        for chunk in file: # text newline iteration - not for bytes
            yield from chunk

The above is only good for what are semantically human readable text files (like plain text, code, markup, markdown etc... essentially anything ascii, utf, latin, etc... encoded) that you should open without the 'b' flag.

Python - List of unique dictionaries

In case the dictionaries are only uniquely identified by all items (ID is not available) you can use the answer using JSON. The following is an alternative that does not use JSON, and will work as long as all dictionary values are immutable

[dict(s) for s in set(frozenset(d.items()) for d in L)]

Is it possible to use "return" in stored procedure?

In Stored procedure, you return the values using OUT parameter ONLY. As you have defined two variables in your example:

   outstaticip OUT VARCHAR2, outcount OUT NUMBER

Just assign the return values to the out parameters i.e. outstaticip and outcount and access them back from calling location. What I mean here is: when you call the stored procedure, you will be passing those two variables as well. After the stored procedure call, the variables will be populated with return values.

If you want to have RETURN value as return from the PL/SQL call, then use FUNCTION. Please note that in case, you would be able to return only one variable as return variable.

Groovy write to file (newline)

I came across this question and inspired by other contributors. I need to append some content to a file once per line. Here is what I did.

class Doh {
   def ln = System.getProperty('line.separator')
   File file //assume it's initialized 

   void append(String content) {
       file << "$content$ln"

Pretty neat I think :)

Invert colors of an image in CSS or JavaScript

Can be done in major new broswers using the code below

.img {

However, if you want it to work across all browsers you need to use Javascript. Something like this gist will do the job.

VBA Print to PDF and Save with Automatic File Name

Hopefully this is self explanatory enough. Use the comments in the code to help understand what is happening. Pass a single cell to this function. The value of that cell will be the base file name. If the cell contains "AwesomeData" then we will try and create a file in the current users desktop called AwesomeData.pdf. If that already exists then try AwesomeData2.pdf and so on. In your code you could just replace the lines filename = Application..... with filename = GetFileName(Range("A1"))

Function GetFileName(rngNamedCell As Range) As String
    Dim strSaveDirectory As String: strSaveDirectory = ""
    Dim strFileName As String: strFileName = ""
    Dim strTestPath As String: strTestPath = ""
    Dim strFileBaseName As String: strFileBaseName = ""
    Dim strFilePath As String: strFilePath = ""
    Dim intFileCounterIndex As Integer: intFileCounterIndex = 1

    ' Get the users desktop directory.
    strSaveDirectory = Environ("USERPROFILE") & "\Desktop\"
    Debug.Print "Saving to: " & strSaveDirectory

    ' Base file name
    strFileBaseName = Trim(rngNamedCell.Value)
    Debug.Print "File Name will contain: " & strFileBaseName

    ' Loop until we find a free file number
        If intFileCounterIndex > 1 Then
            ' Build test path base on current counter exists.
            strTestPath = strSaveDirectory & strFileBaseName & Trim(Str(intFileCounterIndex)) & ".pdf"
            ' Build test path base just on base name to see if it exists.
            strTestPath = strSaveDirectory & strFileBaseName & ".pdf"
        End If

        If (Dir(strTestPath) = "") Then
            ' This file path does not currently exist. Use that.
            strFileName = strTestPath
            ' Increase the counter as we have not found a free file yet.
            intFileCounterIndex = intFileCounterIndex + 1
        End If

    Loop Until strFileName <> ""

    ' Found useable filename
    Debug.Print "Free file name: " & strFileName
    GetFileName = strFileName

End Function

The debug lines will help you figure out what is happening if you need to step through the code. Remove them as you see fit. I went a little crazy with the variables but it was to make this as clear as possible.

In Action

My cell O1 contained the string "FileName" without the quotes. Used this sub to call my function and it saved a file.

Sub Testing()
    Dim filename As String: filename = GetFileName(Range("o1"))

    ActiveWorkbook.Worksheets("Sheet1").Range("A1:N24").ExportAsFixedFormat Type:=xlTypePDF, _
                                              filename:=filename, _
                                              Quality:=xlQualityStandard, _
                                              IncludeDocProperties:=True, _
                                              IgnorePrintAreas:=False, _
End Sub

Where is your code located in reference to everything else? Perhaps you need to make a module if you have not already and move your existing code into there.

How do I tokenize a string in C++?

You can use streams, iterators, and the copy algorithm to do this fairly directly.

#include <string>
#include <vector>
#include <iostream>
#include <istream>
#include <ostream>
#include <iterator>
#include <sstream>
#include <algorithm>

int main()
  std::string str = "The quick brown fox";

  // construct a stream from the string
  std::stringstream strstr(str);

  // use stream iterators to copy the stream to the vector as whitespace separated strings
  std::istream_iterator<std::string> it(strstr);
  std::istream_iterator<std::string> end;
  std::vector<std::string> results(it, end);

  // send the vector to stdout.
  std::ostream_iterator<std::string> oit(std::cout);
  std::copy(results.begin(), results.end(), oit);

Replace console output in Python

Below code will count Message from 0 to 137 each 0.3 second replacing previous number.

Number of symbol to backstage = number of digits.

stream = sys.stdout
for i in range(137):
    stream.write('\b' * (len(str(i)) + 10))
    stream.write("Message : " + str(i))

Giving a border to an HTML table row, <tr>

Yes. I updated my answer DEMO

table td {
    border-top: thin solid; 
    border-bottom: thin solid;

table td:first-child {
     border-left: thin solid;

table td:last-child {
     border-right: thin solid;

If you want to style only one <tr> you can do it with a class: Second DEMO

Are there such things as variables within an Excel formula?

Yes. But not directly.

Simpler way

  • You could post Vlookup() in one cell and use its address in where required. - This is perhaps the only direct way of using variables in Excel.


  • You could define Vlookup(reference)-10 as a wrapper function from within VBE Macros. Press Alt+f12 and use that function

How to implement "confirmation" dialog in Jquery UI dialog?

$("ul li a").live('click', function (e) {

                    .html('<div><h6>Are you sure about this?</h6></div>')
                        modal: true, title: 'Delete message', zIndex: 10000, autoOpen: true,
                        width: 'auto', modal: true, resizable: false,
                        buttons: {
                            Confirm: function () {
                                // $(obj).removeAttr('onclick');                                
                                // $(obj).parents('.Parent').remove();


                            No: function () {
                        Cancel: function (event, ui) {

            return false;

How to see my Eclipse version?

Go to Help -> About Eclipse Sdk

enter image description here

enter image description here

Removing "NUL" characters

Try Find and Replace. type \x00 in Find text box, check the Regular expression option. Leave Replace textbox blank and click on replace all. short cut key for find and replace is ctrl+H.

Print array without brackets and commas

Just initialize a String object with your array

String s=new String(array);

How do I disable the resizable property of a textarea?

You simply use: resize: none; in your CSS.

The resize property specifies whether or not an element is resizable by the user.

Note: The resize property applies to elements whose computed overflow value is something other than "visible".

Also resize not supported in Internet Explorer at the moment.

Here are different properties for resize:

No Resize:

textarea {
  resize: none;

Resize both ways (vertically & horizontally):

textarea {
  resize: both;

Resize vertically:

textarea {
  resize: vertical;

Resize horizontally:

textarea {
  resize: horizontal;

Also if you have width and height in your CSS or HTML, it will prevent your textarea be resized, with a broader browsers support.

How to fix "ImportError: No module named ..." error in Python?

Here is a step-by-step solution:

  1. Add a script called in /home/bodacydo/work/project and edit it like this:

    import programs.my_python_program

    (replace main() with your equivalent method in my_python_program.)

  2. Go to /home/bodacydo/work/project
  3. Run

Explanation: Since python appends to PYTHONPATH the path of the script from which it runs, running will append /home/bodacydo/work/project. And voilà, import foo.tasks will be found.

How do I compute the intersection point of two lines?

The most concise solution I have found uses Sympy:

# import sympy and Point, Line 
from sympy import Point, Line 
p1, p2, p3 = Point(0, 0), Point(1, 1), Point(7, 7) 
l1 = Line(p1, p2) 
# using intersection() method 
showIntersection = l1.intersection(p3) 

Free Rest API to retrieve current datetime as string (timezone irrelevant)

This API gives you the current time and several formats in JSON - Here's a sample response:

  "time": {
    "daysInMonth": 31,
    "millisecond": 283,
    "second": 42,
    "minute": 55,
    "hour": 1,
    "date": 6,
    "day": 3,
    "week": 10,
    "month": 2,
    "year": 2013,
    "zone": "+0000"
  "formatted": {
    "weekday": "Wednesday",
    "month": "March",
    "ago": "a few seconds",
    "calendar": "Today at 1:55 AM",
    "generic": "2013-03-06T01:55:42+00:00",
    "time": "1:55 AM",
    "short": "03/06/2013",
    "slim": "3/6/2013",
    "hand": "Mar 6 2013",
    "handTime": "Mar 6 2013 1:55 AM",
    "longhand": "March 6 2013",
    "longhandTime": "March 6 2013 1:55 AM",
    "full": "Wednesday, March 6 2013 1:55 AM",
    "fullSlim": "Wed, Mar 6 2013 1:55 AM"
  "array": [
  "offset": 1362534942283,
  "unix": 1362534942,
  "utc": "2013-03-06T01:55:42.283Z",
  "valid": true,
  "integer": false,
  "zone": 0