Programs & Examples On #Proxy object

HTML form with side by side input fields

You should put the input for the last name into the same div where you have the first name.

    <label for="username">First Name</label>
    <input id="user_first_name" name="user[first_name]" size="30" type="text" />
    <input id="user_last_name" name="user[last_name]" size="30" type="text" />

Then, in your CSS give your #user_first_name and #user_last_name height and float them both to the left. For example:

    max-width:100px; /*max-width for responsiveness*/


Open directory using C

Here is a simple way to implement ls command using c. To run use for example ./xls /tmp

    #include <dirent.h>
    void main(int argc,char *argv[])
   DIR *dir;
   struct dirent *dent;
   dir = opendir(argv[1]);   

        if((strcmp(dent->d_name,".")==0 || strcmp(dent->d_name,"..")==0 || (*dent->d_name) == '.' ))

How to read a single char from the console in Java (as the user types it)?

There is no portable way to read raw characters from a Java console.

Some platform-dependent workarounds have been presented above. But to be really portable, you'd have to abandon console mode and use a windowing mode, e.g. AWT or Swing.

How to create a timer using tkinter?

from tkinter import *

from tkinter import messagebox

root = Tk()


root.resizable(0, 0)


seconds = 21

def timer():

    global seconds
    if seconds > 0:
        seconds = seconds - 1
        mins = seconds // 60
        m = str(mins)

        if mins < 10:
            m = '0' + str(mins)
        se = seconds - (mins * 60)
        s = str(se)

        if se < 10:
            s = '0' + str(se)
        time.set(m + ':' + s)
        # call this function again in 1,000 milliseconds
        root.after(1000, timer)

    elif seconds == 0:
        messagebox.showinfo('Message', 'Time is completed')

frames = Frame(root, width=500, height=500)


time = StringVar()

timer_display = Label(root, font=('Trebuchet MS', 30, 'bold')), y=100)

timer()  # start the timer


Should I declare Jackson's ObjectMapper as a static field?


com.fasterxml.jackson.databind.type.TypeFactory._findSuperInterfaceChain(Type, Class)
  com.fasterxml.jackson.databind.type.TypeFactory._findSuperTypeChain(Class, Class)
     com.fasterxml.jackson.databind.type.TypeFactory.findTypeParameters(Class, Class, TypeBindings)
        com.fasterxml.jackson.databind.type.TypeFactory.findTypeParameters(JavaType, Class)
           com.fasterxml.jackson.databind.type.TypeFactory._fromParamType(ParameterizedType, TypeBindings)
              com.fasterxml.jackson.databind.type.TypeFactory._constructType(Type, TypeBindings)
                    com.fasterxml.jackson.databind.ObjectMapper.convertValue(Object, TypeReference)

The method _hashMapSuperInterfaceChain in class com.fasterxml.jackson.databind.type.TypeFactory is synchronized. Am seeing contention on the same at high loads.

May be another reason to avoid a static ObjectMapper

How to rename files and folder in Amazon S3?

Here's how you do it in .NET, using S3 .NET SDK:

var client = new Amazon.S3.AmazonS3Client(_credentials, _config);
client.CopyObject(oldBucketName, oldfilepath, newBucketName, newFilePath);
client.DeleteObject(oldBucketName, oldfilepath);

P.S. try to use use "Async" versions of the client methods where possible, even though I haven't done so for readability

Sum values in foreach loop php

foreach($group as $key=>$value)
   echo $key. " = " .$value. "<br>"; 
   $total+= $value;
echo $total;

Authenticated HTTP proxy with Java

You're almost there, you just have to append:


How to make/get a multi size .ico file?

This can be done for free using GIMP.

It uses the ability of GIMP to have each layer a different size.

I created the following layers sized correctly.

  • 256x256 will be saved as 32bpp 8bit alpha
  • 48x48 will be saved as 32bpp 8bit alpha
  • 48x48 will be saved as 8bpp 1bit alpha
  • 32x32 will be saved as 32bpp 8bit alpha
  • 32x32 will be saved as 8bpp 1bit alpha
  • 32x32 will be saved as 4bpp 1bit alpha
  • 16x16 will be saved as 32bpp 8bit alpha
  • 16x16 will be saved as 8bpp 1bit alpha
  • 16x16 will be saved as 4bpp 1bit alpha


  • You may need to check other resources to confirm to yourself that this is a sensible list of resolutions and colour depths.
  • Make sure you use transparency round the outside of your image, and anti-aliased edges. You should see the grey checkerboard effect round the outside of your layers to indicate they are transparent
  • The 16x16 icons will need to be heavily edited by hand using a 1 pixel wide pencil and the eyedropper tool to make them look any good.
  • Do not change colour depth / Mode in GIMP. Leave it as RGB
  • You change the colour depths when you save as an .ico - GIMP pops up a special dialog box for changing the colour settings for each layer

jQuery datepicker, onSelect won't work

The function datepicker is case sensitive and all lowercase. The following however works fine for me:

$(document).ready(function() {
  $('.date-pick').datepicker( {
    onSelect: function(date) {
    selectWeek: true,
    inline: true,
    startDate: '01/01/2000',
    firstDay: 1

Swift - Integer conversion to Hours/Minutes/Seconds

Swift 5 & String Response, In presentable format

public static func secondsToHoursMinutesSecondsStr (seconds : Int) -> String {
      let (hours, minutes, seconds) = secondsToHoursMinutesSeconds(seconds: seconds);
      var str = hours > 0 ? "\(hours) h" : ""
      str = minutes > 0 ? str + " \(minutes) min" : str
      str = seconds > 0 ? str + " \(seconds) sec" : str
      return str

public static func secondsToHoursMinutesSeconds (seconds : Int) -> (Int, Int, Int) {
        return (seconds / 3600, (seconds % 3600) / 60, (seconds % 3600) % 60)


print(secondsToHoursMinutesSecondsStr(seconds: 20000)) // Result = "5 h 33 min 20 sec"

Sort hash by key, return hash in Ruby

You gave the best answer to yourself in the OP: Hash[h.sort] If you crave for more possibilities, here is in-place modification of the original hash to make it sorted:

h.keys.sort.each { |k| h[k] = h.delete k }

When do you use map vs flatMap in RxJava?

The question is When do you use map vs flatMap in RxJava?. And I think a simple demo is more specific.

When you want to convert item emitted to another type , in your case converting file to String, map and flatMap can both work. But I prefer map operator because it's more clearly.

However in some place, flatMap can do magic work but map can't. For example, I want to get a user's info but I have to first get his id when user login in. Obviously I need two requests and they are in order.

Let's begin.

Observable<LoginResponse> login(String email, String password);

Observable<UserInfo> fetchUserInfo(String userId);

Here are two methods, one for login returned Response, and another for fetching user info.

login(email, password)
        .flatMap(response ->
        .subscribe(userInfo -> {
            // get user info and you update ui now

As you see, in function flatMap applies, at first I get user id from Response then fetch user info. When two requests are finished, we can do our job such as updating UI or save data into database.

However if you use map you can't write such nice code. In a word, flatMap can help us serialize requests.

How to hide a navigation bar from first ViewController in Swift?

Swift 3

override func viewWillAppear(_ animated: Bool) {

    // Hide the navigation bar on the this view controller
    self.navigationController?.setNavigationBarHidden(true, animated: animated)

override func viewWillDisappear(_ animated: Bool) {

    // Show the navigation bar on other view controllers
    self.navigationController?.setNavigationBarHidden(false, animated: animated)

Create Excel files from C# without office

If you're interested in making .xlsx (Office 2007 and beyond) files, you're in luck. Office 2007+ uses OpenXML which for lack of a more apt description is XML files inside of a zip named .xlsx

Take an excel file (2007+) and rename it to .zip, you can open it up and take a look. If you're using .NET 3.5 you can use the System.IO.Packaging library to manipulate the relationships & zipfile itself, and linq to xml to play with the xml (or just DOM if you're more comfortable).

Otherwise id reccomend DotNetZip, a powerfull library for manipulation of zipfiles.

OpenXMLDeveloper has lots of resources about OpenXML and you can find more there.

If you want .xls (2003 and below) you're going to have to look into 3rd party libraries or perhaps learn the file format yourself to achieve this without excel installed.

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

You can create extension method like:

public static IEnumerable<TResult> LeftOuterJoin<TSource, TInner, TKey, TResult>(this IEnumerable<TSource> source, IEnumerable<TInner> other, Func<TSource, TKey> func, Func<TInner, TKey> innerkey, Func<TSource, TInner, TResult> res)
        return from f in source
               join b in other on func.Invoke(f) equals innerkey.Invoke(b) into g
               from result in g.DefaultIfEmpty()
               select res.Invoke(f, result);

Calling onclick on a radiobutton list using javascript

The problem here is that the rendering of a RadioButtonList wraps the individual radio buttons (ListItems) in span tags and even when you assign a client-side event handler to the list item directly using Attributes it assigns the event to the span. Assigning the event to the RadioButtonList assigns it to the table it renders in.

The trick here is to add the ListItems on the aspx page and not from the code behind. You can then assign the JavaScript function to the onClick property. This blog post; attaching client-side event handler to radio button list by Juri Strumpflohner explains it all.

This only works if you know the ListItems in advance and does not help where the items in the RadioButtonList need to be dynamically added using the code behind.

How to clone ArrayList and also clone its contents?

I have found a way, you can use json to serialize/unserialize the list. The serialized list holds no reference to the original object when unserialized.

Using gson:

List<CategoryModel> originalList = new ArrayList<>(); // add some items later
String listAsJson = gson.toJson(originalList);
List<CategoryModel> newList = new Gson().fromJson(listAsJson, new TypeToken<List<CategoryModel>>() {}.getType());

You can do that using jackson and any other json library too.

How to print a list in Python "nicely"

Simply by "unpacking" the list in the print function argument and using a newline (\n) as separator.

print(*lst, sep='\n')

lst = ['foo', 'bar', 'spam', 'egg']
print(*lst, sep='\n')


Passing array in GET for a REST call

As @Ravi_MCA mentioned, /users?ids[]=id1&ids[]=id2 worked for me, too.

When you want to send an array through PATCH or POST method, it's better to use JSON or XML. (I use JSON)
In HTTP Request body you should follow like this:

{"params":["arg1", "arg2", ...]}

You can even use JSON object instead of array.

python - if not in list

if I got it right, you can try

for item in [x for x in checklist if x not in mylist]:
    print (item)

What does the "~" (tilde/squiggle/twiddle) CSS selector mean?

Note that in an attribute selector (e.g., [attr~=value]), the tilde

Represents an element with an attribute name of attr whose value is a whitespace-separated list of words, one of which is exactly value.

How to open the terminal in Atom?

First, you should install "platformio-ide-terminal": Open "Preferences ?," >> Click "+ Install" >> In "Search packages" type "platformio-ide-terminal" >> Click "Install".

And answering exactly the question. If you have previously installed, just use:

  • Shortcut: ctrl-` or Option+Command+T (??T)
  • by Menu: Go to Packages > platformio-ide-terminal [or other] > New terminal

How to format code in Xcode?

  1. Select the block of code that you want indented.

  2. Right-click (or, on Mac, Ctrl-click).

  3. Structure → Re-indent

CSS Input with width: 100% goes outside parent's bound

If all above fail, try setting the following properties for your input, to have it take max space but not overflow:

input {
    min-width: 100%;
    max-width: 100%;

How to get full path of selected file on change of <input type=‘file’> using javascript, jquery-ajax?

You can get the full path of the selected file to upload only by IE11 and MS Edge.

var fullPath = Request.Form.Files["myFile"].FileName;

MySQL connection not working: 2002 No such file or directory

enable and start mariadb service

sudo systemctl enable mariadb.service

sudo systemctl start mariadb.service

Is it possible only to declare a variable without assigning any value in Python?

Well, if you want to check if a variable is defined or not then why not check if its in the locals() or globals() arrays? Your code rewritten:

for index in sequence:
   if 'value' not in globals() and conditionMet:
       value = index

If it's a local variable you are looking for then replace globals() with locals().

Difference between @Mock and @InjectMocks

@Mock is used to declare/mock the references of the dependent beans, while @InjectMocks is used to mock the bean for which test is being created.

For example:

public class A{

   public class B b;

   public void doSomething(){



test for class A:

public class TestClassA{

   public class B b;

   public class A a;

   public testDoSomething(){



What does the term "canonical form" or "canonical representation" in Java mean?

Canonical Data in RDBMS, Graph Data;
Think as "Normalization" or "Normal form" of a data in a RDBMS. Same data exists in different tables, represented with a unique identifier and mapped it in different tables.
Think a single form of a data in Graph Database that represented in many triples.

Major benefit of it is to make Dml (Data manipulation) more efficient since you can upsert (insert/update) only one value instead of many.

How can I delete all cookies with JavaScript?

This is a function we are using in our application and it is working fine.

delete cookie: No argument method

function clearListCookies()
    var cookies = document.cookie.split(";");
    for (var i = 0; i < cookies.length; i++)
        var spcook =  cookies[i].split("=");
    function deleteCookie(cookiename)
        var d = new Date();
        d.setDate(d.getDate() - 1);
        var expires = ";expires="+d;
        var name=cookiename;
        var value="";
        document.cookie = name + "=" + value + expires + "; path=/acc/html";                    
    window.location = ""; // TO REFRESH THE PAGE

Edit: This will delete the cookie by setting it to yesterday's date.

Index Error: list index out of range (Python)

Generally it means that you are providing an index for which a list element does not exist.

E.g, if your list was [1, 3, 5, 7], and you asked for the element at index 10, you would be well out of bounds and receive an error, as only elements 0 through 3 exist.

How to convert DateTime to a number with a precision greater than days in T-SQL?

SELECT CAST(CONVERT(datetime,'2009-06-15 23:01:00') as float)

yields 39977.9590277778

How do I get an OAuth 2.0 authentication token in C#

This example get token thouth HttpWebRequest

        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(pathapi);
        request.Method = "POST";
        string postData = "grant_type=password";
        ASCIIEncoding encoding = new ASCIIEncoding();
        byte[] byte1 = encoding.GetBytes(postData);

        request.ContentType = "application/x-www-form-urlencoded";

        request.ContentLength = byte1.Length;
        Stream newStream = request.GetRequestStream();
        newStream.Write(byte1, 0, byte1.Length);

        HttpWebResponse response = request.GetResponse() as HttpWebResponse;            
        using (Stream responseStream = response.GetResponseStream())
            StreamReader reader = new StreamReader(responseStream, Encoding.UTF8);
            getreaderjson = reader.ReadToEnd();

PHP Remove elements from associative array

for single array Item use reset($item)

What is "origin" in Git?

Git has the concept of "remotes", which are simply URLs to other copies of your repository. When you clone another repository, Git automatically creates a remote named "origin" and points to it.

You can see more information about the remote by typing git remote show origin.

What is a regular expression which will match a valid domain name without a subdomain?


[domain - lower case letters and 0-9 only] [can have a hyphen] + [TLD - lower case only, must be beween 2 and 7 letters long] is brilliant for testing regular expressions!
Edit: Updated TLD maximum to 7 characters for '.rentals' as Dan Caddigan pointed out.

set value of input field by php variable's value

inside the Form, You can use this code. Replace your variable name (i use $variable)

<input type="text" value="<?php echo (isset($variable))?$variable:'';?>">

jQuery Ajax Request inside Ajax Request

    url: "<?php echo site_url('upToWeb/ajax_edit/')?>/" + id,
    type: "GET",
    dataType: "JSON",
    success: function (data) {
        if (data.web == 0) {
            if (confirm('Data product upToWeb ?')) {
                    url: "<?php echo site_url('upToWeb/set_web/')?>/" + data.id_item,
                    type: "post",
                    dataType: "json",
                    data: {web: 1},
                    success: function (respons) {
                        location.href = location.pathname;
                    error: function (xhr, ajaxOptions, thrownError) { // Ketika terjadi error
                        alert(xhr.responseText); // munculkan alert
        else {
            if (confirm('Data product DownFromWeb ?')) {
                    url: "<?php echo site_url('upToWeb/set_web/')?>/" + data.id_item,
                    type: "post",
                    dataType: "json",
                    data: {web: 0},
                    success: function (respons) {
                        location.href = location.pathname;
                    error: function (xhr, ajaxOptions, thrownError) { // Ketika terjadi error
                        alert(xhr.responseText); // munculkan alert

    error: function (jqXHR, textStatus, errorThrown) {
        alert('Error get data from ajax');


How to change the port number for Asp.Net core app?

We can use this command to run our host project via Windows Powershell without IIS and visual studio on a separate port. Default of krestel web server is 5001

$env:ASPNETCORE_URLS="http://localhost:22742" ; dotnet run

How to copy file from HDFS to the local file system

bin/hadoop fs -put /localfs/destination/path /hdfs/source/path 

Should I use window.navigate or document.location in JavaScript?

support for document.location is also good though its a deprecated method. I've been using this method for a while with no problems. you can refer here for more details:

Why am I seeing "TypeError: string indices must be integers"?

As a rule of thumb, when I receive this error in Python I compare the function signature with the function execution.

For example:

def print_files(file_list, parent_id):
    for file in file_list:
        print(title: %s, id: %s' % (file['title'], file['id']

So if I'll call this function with parameters placed in the wrong order and pass the list as the 2nd argument and a string as the 1st argument:

print_files(parent_id, list_of_files) # <----- Accidentally switching arguments location

The function will try to iterate over the parent_id string instead of file_list and it will expect to see the index as an integer pointing to the specific character in string and not an index which is a string (title or id).

This will lead to the TypeError: string indices must be integers error.

Due to its dynamic nature (as opposed to languages like Java, C# or Typescript), Python will not inform you about this syntax error.

Getting started with Haskell

The first answer is a very good one. In order to get to the Expert level, you should do a PhD with some of the Experts themselves.

I suggest you to visit the Haskell page: There you have a lot of material, and a lot of references to the most up-to-date stuff in Haskell, approved by the Haskell community.

Python: access class property from string

Extending Alex's answer slightly:

class User:
    def __init__(self): = [1,2,3]
        self.other_data = [4,5,6]
    def doSomething(self, source):
        dataSource = getattr(self,source)
        return dataSource

A = User()
print A.doSomething("data")
print A.doSomething("other_data")

will yield:

[1, 2, 3]
[4, 5, 6]

However, personally I don't think that's great style - getattr will let you access any attribute of the instance, including things like the doSomething method itself, or even the __dict__ of the instance. I would suggest that instead you implement a dictionary of data sources, like so:

class User:
    def __init__(self):

        self.data_sources = {
            "data": [1,2,3],

    def doSomething(self, source):
        dataSource = self.data_sources[source]
        return dataSource

A = User()

print A.doSomething("data")
print A.doSomething("other_data")

again yielding:

[1, 2, 3]
[4, 5, 6]

class << self idiom in Ruby

? singleton method is a method that is defined only for a single object.


class SomeClass
  class << self
    def test

test_obj =

def test_obj.test_2

class << test_obj
  def test_3

puts "Singleton's methods of SomeClass"
puts SomeClass.singleton_methods
puts '------------------------------------------'
puts "Singleton's methods of test_obj"
puts test_obj.singleton_methods

Singleton's methods of SomeClass


Singleton's methods of test_obj



Given a starting and ending indices, how can I copy part of a string in C?

Have you checked strncpy?

char * strncpy ( char * destination, const char * source, size_t num );

You must realize that begin and end actually defines a num of bytes to be copied from one place to another.

How do I add a reference to the MySQL connector for .NET?

In Visual Studio you can use nuget to download the latest version. Just right click on the project and click 'Manage NuGet Packages' then search online for MySql.Data and install.

jQuery Scroll To bottom of the page

Using 'document.body.clientHeight' you can get the seen height of the body elements

$('html, body').animate({
    scrollTop: $("#particularDivision").offset().top - document.body.clientHeight + $("#particularDivision").height()
}, 1000);

this scrolls at the id 'particularDivision'

Cannot read property 'getContext' of null, using canvas

Write code in this manner ...

<canvas id="canvas" width="640" height="480"></canvas>
var Grid = function(width, height) {
    this.draw = function() {
    var canvas = document.getElementById("canvas");
    if(canvas.getContext) {
        var context = canvas.getContext("2d");
        for(var i = 0; i < width; i++) {
            for(var j = 0; j < height; j++) {
                if(isLive(i, j)) {
                    context.fillStyle = "lightblue";
                else {
                    context.fillStyle = "yellowgreen";
                context.fillRect(i*15, j*15, 14, 14);

First write canvas tag and then write script tag. And write script tag in body.

C# how to wait for a webpage to finish loading before continuing

Check out the WatiN project:

Inspired by Watir development of WatiN started in December 2005 to make a similar kind of Web Application Testing possible for the .Net languages. Since then WatiN has grown into an easy to use, feature rich and stable framework. WatiN is developed in C# and aims to bring you an easy way to automate your tests with Internet Explorer and FireFox using .Net...

Postman: How to make multiple requests at the same time

Run all Collection in a folder in parallel:

'use strict';

global.Promise = require('bluebird');
const path = require('path');
const newman =  Promise.promisifyAll(require('newman'));
const fs = Promise.promisifyAll(require('fs'));
const environment = 'postman_environment.json';
const FOLDER = path.join(__dirname, 'Collections_Folder');

let files = fs.readdirSync(FOLDER);
files => path.join(FOLDER, file))
console.log(files);, file => {

    return newman.runAsync({
    collection: file, // your collection
    environment: path.join(__dirname, environment), //your env
    reporters: ['cli']

}, {
   concurrency: 2

Oracle date to string conversion

The data in COL1 is in dd-mon-yy

No it's not. A DATE column does not have any format. It is only converted (implicitely) to that representation by your SQL client when you display it.

If COL1 is really a DATE column using to_date() on it is useless because to_date() converts a string to a DATE.

You only need to_char(), nothing else:

SELECT TO_CHAR(col1, 'mm/dd/yyyy') 

What happens in your case is that calling to_date() converts the DATE into a character value (applying the default NLS format) and then converting that back to a DATE. Due to this double implicit conversion some information is lost on the way.


So you did make that big mistake to store a DATE in a character column. And that's why you get the problems now.

The best (and to be honest: only sensible) solution is to convert that column to a DATE. Then you can convert the values to any rerpresentation that you want without worrying about implicit data type conversion.

But most probably the answer is "I inherited this model, I have to cope with it" (it always is, apparently no one ever is responsible for choosing the wrong datatype), then you need to use RR instead of YY:

SELECT TO_CHAR(TO_DATE(COL1,'dd-mm-rr'), 'mm/dd/yyyy')

should do the trick. Note that I also changed mon to mm as your example is 27-11-89 which has a number for the month, not an "word" (like NOV)

For more details see the manual:

Rename a dictionary key

Suppose you want to rename key k3 to k4:

temp_dict = {'k1':'v1', 'k2':'v2', 'k3':'v3'}
temp_dict['k4']= temp_dict.pop('k3')

How to fix 'android.os.NetworkOnMainThreadException'?

New Thread and AsyncTask solutions have been explained already.

AsyncTask should ideally be used for short operations. Normal Thread is not preferable for Android.

Have a look at alternate solution using HandlerThread and Handler


Handy class for starting a new thread that has a looper. The looper can then be used to create handler classes. Note that start() must still be called.


A Handler allows you to send and process Message and Runnable objects associated with a thread's MessageQueue. Each Handler instance is associated with a single thread and that thread's message queue. When you create a new Handler, it is bound to the thread / message queue of the thread that is creating it -- from that point on, it will deliver messages and runnables to that message queue and execute them as they come out of the message queue.


  1. Create HandlerThread

  2. Call start() on HandlerThread

  3. Create Handler by getting Looper from HanlerThread

  4. Embed your Network operation related code in Runnable object

  5. Submit Runnable task to Handler

Sample code snippet, which address NetworkOnMainThreadException

HandlerThread handlerThread = new HandlerThread("URLConnection");
handler mainHandler = new Handler(handlerThread.getLooper());

Runnable myRunnable = new Runnable() {
    public void run() {
        try {
            Log.d("Ravi", "Before IO call");
            URL page = new URL("");
            StringBuffer text = new StringBuffer();
            HttpURLConnection conn = (HttpURLConnection) page.openConnection();
            InputStreamReader in = new InputStreamReader((InputStream) conn.getContent());
            BufferedReader buff = new BufferedReader(in);
            String line;
            while ( (line =  buff.readLine()) != null) {
                text.append(line + "\n");
            Log.d("Ravi", "After IO call");

        }catch( Exception err){

Pros of using this approach:

  1. Creating new Thread/AsyncTask for each network operation is expensive. The Thread/AsyncTask will be destroyed and re-created for next Network operations. But with Handler and HandlerThread approach, you can submit many network operations (as Runnable tasks) to single HandlerThread by using Handler.

"replace" function examples

Be aware that the third parameter (value) in the examples given above: the value is a constant (e.g. 'Z' or c(20,30)).

Defining the third parameter using values from the data frame itself can lead to confusion.

E.g. with a simple data frame such as this (using dplyr::data_frame):

tmp <- data_frame(a=1:10, b=sample(LETTERS[24:26], 10, replace=T))

This will create somthing like this:

       a     b
   (int) (chr)
1      1     X
2      2     Y
3      3     Y
4      4     X
5      5     Z


Now suppose you want wanted to do, was to multiply the values in column 'a' by 2, but only where column 'b' is "X". My immediate thought would be something like this:

with(tmp, replace(a, b=="X", a*2))

That will not provide the desired outcome, however. The a*2 will defined as a fixed vector rather than a reference to the 'a' column. The vector 'a*2' will thus be

[1]  2  4  6  8 10 12 14 16 18 20

at the start of the 'replace' operation. Thus, the first row where 'b' equals "X", the value in 'a' will be placed by 2. The second time, it will be replaced by 4, etc ... it will not be replaced by two-times-the-value-of-a in that particular row.

Match linebreaks - \n or \r\n?

In PCRE \R matches \n, \r and \r\n.

NHibernate.MappingException: No persister for: XYZ

Sounds like you forgot to add a mapping assembly to the session factory configuration..

If you're using app.config...

    <property name="show_sql">true</property>
    <property name="query.substitutions">true 1, false 0, yes 'Y', no 'N'</property>
    <mapping assembly="Project.DomainModel"/>  <!-- Here -->

How to scroll to top of long ScrollView layout?

Very easy

    ScrollView scroll = (ScrollView) findViewById(;

Remove Project from Android Studio

You must close the project, hover over the project in the welcome screen, then press the delete button.

Call a VBA Function into a Sub Procedure

Here are some of the different ways you can call things in Microsoft Access:

To call a form sub or function from a module

The sub in the form you are calling MUST be public, as in:

Public Sub DoSomething()
  MsgBox "Foo"
End Sub

Call the sub like this:

Call Forms("form1").DoSomething

The form must be open before you make the call.

To call an event procedure, you should call a public procedure within the form, and call the event procedure within this public procedure.

To call a subroutine in a module from a form

Public Sub DoSomethingElse()
  MsgBox "Bar"
End Sub

...just call it directly from your event procedure:

Call DoSomethingElse

To call a subroutine from a form without using an event procedure

If you want, you can actually bind the function to the form control's event without having to create an event procedure under the control. To do this, you first need a public function in the module instead of a sub, like this:

Public Function DoSomethingElse()
  MsgBox "Bar"
End Function

Then, if you have a button on the form, instead of putting [Event Procedure] in the OnClick event of the property window, put this:


When you click the button, it will call the public function in the module.

To call a function instead of a procedure

If calling a sub looks like this:

Call MySub(MyParameter)

Then calling a function looks like this:


where Result is a variable of type returned by the function.

NOTE: You don't always need the Call keyword. Most of the time, you can just call the sub like this:


Delete files older than 10 days using shell script in Unix

find is the common tool for this kind of task :

find ./my_dir -mtime +10 -type f -delete


  • ./my_dir your directory (replace with your own)
  • -mtime +10 older than 10 days
  • -type f only files
  • -delete no surprise. Remove it to test your find filter before executing the whole command

And take care that ./my_dir exists to avoid bad surprises !

How to get address of a pointer in c/c++?

&a gives address of a - &p gives address of p.

int * * p_to_p = &p;

The listener supports no services

You need to add your ORACLE_HOME definition in your listener.ora file. Right now its not registered with any ORACLE_HOME.

Sample listener.ora

abc =
      (ADDRESS = (PROTOCOL = TCP)(HOST = = 1521))

SID_LIST_abc =
    (SID_DESC =
      (ORACLE_HOME= /abc/DbTier/11.2.0)
      (SID_NAME = abc)

PHP get dropdown value and text

$animals = array('--Select Animal--', 'Cat', 'Dog', 'Cow');
$selected_key = $_POST['animal'];
$selected_val = $animals[$_POST['animal']];

Use your $animals list to generate your dropdown list; you now can get the key & the value of that key.

How to loop through each and every row, column and cells in a GridView and get its value

The easiest would be using a foreach:

foreach(GridViewRow row in GridView2.Rows)
    // here you'll get all rows with RowType=DataRow
    // others like Header are omitted in a foreach

Edit: According to your edits, you are accessing the column incorrectly, you should start with 0:

foreach(GridViewRow row in GridView2.Rows)
    for(int i = 0; i < GridView2.Columns.Count; i++)
        String header = GridView2.Columns[i].HeaderText;
        String cellText = row.Cells[i].Text;

Where to find the complete definition of off_t type?

Since this answer still gets voted up, I want to point out that you should almost never need to look in the header files. If you want to write reliable code, you're much better served by looking in the standard. A better question than "how is off_t defined on my machine" is "how is off_t defined by the standard?". Following the standard means that your code will work today and tomorrow, on any machine.

In this case, off_t isn't defined by the C standard. It's part of the POSIX standard, which you can browse here.

Unfortunately, off_t isn't very rigorously defined. All I could find to define it is on the page on sys/types.h:

blkcnt_t and off_t shall be signed integer types.

This means that you can't be sure how big it is. If you're using GNU C, you can use the instructions in the answer below to ensure that it's 64 bits. Or better, you can convert to a standards defined size before putting it on the wire. This is how projects like Google's Protocol Buffers work (although that is a C++ project).

So, I think "where do I find the definition in my header files" isn't the best question. But, for completeness here's the answer:

On my machine (and most machines using glibc) you'll find the definition in bits/types.h (as a comment says at the top, never directly include this file), but it's obscured a bit in a bunch of macros. An alternative to trying to unravel them is to look at the preprocessor output:

#include <stdio.h>
#include <sys/types.h>

int main(void) {
  off_t blah;

  return 0;

And then:

$ gcc -E sizes.c  | grep __off_t
typedef long int __off_t;

However, if you want to know the size of something, you can always use the sizeof() operator.

Edit: Just saw the part of your question about the __. This answer has a good discussion. The key point is that names starting with __ are reserved for the implementation (so you shouldn't start your own definitions with __).

Redefine tab as 4 spaces

Put your desired settings in the ~/.vimrc file -- See below for some guidelines and best practices.

There are four main ways to use tabs in Vim:

  1. Always keep 'tabstop' at 8, set 'softtabstop' and 'shiftwidth' to 4 (or 3 or whatever you prefer) and use 'noexpandtab'. Then Vim will use a mix of tabs and spaces, but typing and will behave like a tab appears every 4 (or 3) characters.

    Note: Setting 'tabstop' to any other value than 8 can make your file appear wrong in many places (e.g., when printing it).

  2. Set 'tabstop' and 'shiftwidth' to whatever you prefer and use 'expandtab'. This way you will always insert spaces. The formatting will never be messed up when 'tabstop' is changed.

  3. Set 'tabstop' and 'shiftwidth' to whatever you prefer and use a |modeline| to set these values when editing the file again. Only works when using Vim to edit the file.

  4. Always set 'tabstop' and 'shiftwidth' to the same value, and 'noexpandtab'. This should then work (for initial indents only) for any tabstop setting that people use. It might be nice to have tabs after the first non-blank inserted as spaces if you do this though. Otherwise aligned comments will be wrong when 'tabstop' ischanged.


Check variable equality against a list of values

Using the answers provided, I ended up with the following: = function() {
    for(var i=0; i<arguments.length; i++)
       if(arguments[i] == this) return true;
    return false;

It can be called like:

if(, 3, 12)) {
    // ...

Edit: I came across this 'trick' lately which is useful if the values are strings and do not contain special characters. For special characters is becomes ugly due to escaping and is also more error-prone due to that.


To be more precise, this will check the exact string, but then again is more complicated for a simple equality test:


SQLRecoverableException: I/O Exception: Connection reset

We experienced these errors intermittently after upgraded from 11g to 12c and our java was on 1.6.

The fix for us was to upgrade java and jdbc from 6 to 7

export JAVA_HOME='/usr/java1.7'

export CLASSPATH=/u01/app/oracle/product/12.1.0/dbhome_1/jdbc/libojdbc7.jar:$CLASSPATH 

Several days later, still intermittent connection resets.

We ended up removing all the java 7 above. Java 6 was fine. The problem was fixed by adding this to our user bash_profile.

Our groovy scripts that were experiencing the error were using /dev/random on our batch VM server. Below forced java and groovy to use /dev/urandom.


How to compile a Perl script to a Windows executable with Strawberry Perl?

  :: short answer :
  :: perl -MCPAN -e "install PAR::Packer" 
  pp -o <<DesiredExeName>>.exe <<MyFancyPerlScript>> 

  :: long answer - create the following cmd , adjust vars to your taste ...
  :: next_line_is_templatized
  :: v1.0.0
  :: disable the echo
  @echo off

  :: this is part of the name of the file - not used
  set _Action=run

  :: the name of the Product next_line_is_templatized
  set _ProductName=morphus

  :: the version of the current Product next_line_is_templatized
  set _ProductVersion=1.2.3

  :: could be dev , test , dev , prod next_line_is_templatized
  set _ProductType=dev

  :: who owns this Product / environment next_line_is_templatized
  set _ProductOwner=ysg

  :: identifies an instance of the tool ( new instance for this version could be created by simply changing the owner )   
  set _EnvironmentName=%_ProductName%.%_ProductVersion%.%_ProductType%.%_ProductOwner%

  :: go the run dir
  cd %~dp0

  :: do 4 times going up
  for /L %%i in (1,1,5) do pushd ..

  :: The BaseDir is 4 dirs up than the run dir
  set _ProductBaseDir=%CD%
  :: debug echo BEFORE _ProductBaseDir is %_ProductBaseDir%
  :: remove the trailing \

  IF %_ProductBaseDir:~-1%==\ SET _ProductBaseDir=%_ProductBaseDir:~0,-1%
  :: debug echo AFTER _ProductBaseDir is %_ProductBaseDir%
  :: debug pause

  :: The version directory of the Product 
  set _ProductVersionDir=%_ProductBaseDir%\%_ProductName%\%_EnvironmentName%

  :: the dir under which all the perl scripts are placed
  set _ProductVersionPerlDir=%_ProductVersionDir%\sfw\perl

  :: The Perl script performing all the tasks
  set _PerlScript=%_ProductVersionPerlDir%\

  :: where the log events are stored 
  set _RunLog=%_ProductVersionDir%\data\log\compile-%_ProductName%.cmd.log

  :: define a favorite editor 
  set _MyEditor=textpad

  ECHO Check the variables 
  set _
  :: debug PAUSE
  :: truncate the run log
  echo date is %date% time is %time% > %_RunLog%

  :: uncomment this to debug all the vars 
  :: debug set  >> %_RunLog%

  :: for each perl pm and or pl file to check syntax and with output to logs
  for /f %%i in ('dir %_ProductVersionPerlDir%\*.pl /s /b /a-d' ) do echo %%i >> %_RunLog%&perl -wc %%i | tee -a  %_RunLog% 2>&1

  :: for each perl pm and or pl file to check syntax and with output to logs
  for /f %%i in ('dir %_ProductVersionPerlDir%\*.pm /s /b /a-d' ) do echo %%i >> %_RunLog%&perl -wc %%i | tee -a  %_RunLog% 2>&1

  :: now open the run log
  cmd /c start /max %_MyEditor% %_RunLog%

  :: this is the call without debugging
  :: old 
  echo CFPoint1  OK The run cmd script %0 is executed >> %_RunLog%
  echo CFPoint2  OK  compile the exe file  STDOUT and STDERR  to a single _RunLog file >> %_RunLog%
  cd %_ProductVersionPerlDir%

  pp -o %_Action%_%_ProductName%.exe %_PerlScript% | tee -a %_RunLog% 2>&1 

  :: open the run log
  cmd /c start /max %_MyEditor% %_RunLog%

  :: uncomment this line to wait for 5 seconds
  :: ping localhost -n 5

  :: uncomment this line to see what is happening 
  :: PAUSE

  :: Purpose: 
  :: To compile every *.pl file into *.exe file under a folder 
  :: Requirements : 
  :: perl , pp , win gnu utils tee 
  :: perl -MCPAN -e "install PAR::Packer" 
  :: text editor supporting <<textEditor>> <<FileNameToOpen>> cmd call syntax
  :: VersionHistory
  :: 1.0.0 --- 2012-06-23 12:05:45 --- ysg --- Initial creation from run_morphus.cmd
  :: eof v1.0.0

How to use the toString method in Java?

Use of the String.toString:

Whenever you require to explore the constructor called value in the String form, you can simply use String.toString... for an example...

package pack1;

import java.util.*;

class Bank {

    String n;
    String add;
    int an;
    int bal;
    int dep;

    public Bank(String n, String add, int an, int bal) {

        this.add = add;
        this.bal = bal; = an;
        this.n = n;


    public String toString() {
        return "Name of the customer.:" + this.n + ",, "
                + "Address of the customer.:" + this.add + ",, " + "A/c no..:"
                + + ",, " + "Balance in A/c..:" + this.bal;

public class Demo2 {

    public static void main(String[] args) {

        List<Bank> l = new LinkedList<Bank>();

        Bank b1 = new Bank("naseem1", "Darbhanga,bihar", 123, 1000);
        Bank b2 = new Bank("naseem2", "patna,bihar", 124, 1500);
        Bank b3 = new Bank("naseem3", "madhubani,bihar", 125, 1600);
        Bank b4 = new Bank("naseem4", "samastipur,bihar", 126, 1700);
        Bank b5 = new Bank("naseem5", "muzafferpur,bihar", 127, 1800);
        Iterator<Bank> i = l.iterator();
        while (i.hasNext()) {


... copy this program into your Eclipse, and run it... you will get the ideas about String.toString...

Sending email with gmail smtp with codeigniter email library

send html email via codeiginater


    $config['mailtype'] = "html";
    $this->email->from('[email protected]', 'Website');
    $list = array('[email protected]', '[email protected]');
    $data = array();
    $htmlMessage = $this->parser->parse('messages/email', $data, true);
    $this->email->subject('This is an email test');

    if ($this->email->send()) {
        echo 'Your email was sent, thanks chamil.';
    } else {

auto create database in Entity Framework Core

My answer is very similar to Ricardo's answer, but I feel that my approach is a little more straightforward simply because there is so much going on in his using function that I'm not even sure how exactly it works on a lower level.

So for those who want a simple and clean solution that creates a database for you where you know exactly what is happening under the hood, this is for you:

public Startup(IHostingEnvironment env)
    using (var client = new TargetsContext())

This pretty much means that within the DbContext that you created (in this case, mine is called TargetsContext), you can use an instance of the DbContext to ensure that the tables defined with in the class are created when Startup.cs is run in your application.

Convert boolean result into number/integer

You could do this by simply extending the boolean prototype

Boolean.prototype.intval = function(){return ~~this}

It is not too easy to understand what is going on there so an alternate version would be

Boolean.prototype.intval = function(){return (this == true)?1:0}

having done which you can do stuff like


When I use booleans to store conditions I often convert them to bitfields in which case I end up using an extended version of the prototype function

Boolean.prototype.intval = function(places)
 places = ('undefined' == typeof(places))?0:places; 
 return (~~this) << places

with which you can do


which produces 4 as its output.

How to fix the height of a <div> element?

You can try max-height: 70px; See if that works.

How do I force a favicon refresh?

I know this is a really old question but it is also one that is still relevant, though these days applies only to mozilla. (I have no idea what explorer does coz we don't code for non standard browsers).

Chrome is well behaved if one includes an icon tag in the header.

Although mozilla are well aware of the issue, as usual, they never fix the annoying small stuff. Even 6 years later.

So, there are two ways of forcing an icon refresh with firefox.

  1. Have all your clients uninstall firefox. Then re-install.

  2. Manually type just the domain in the url bar - do not use http or www just the domain (

This assumes of course that your ns records include resolution for the domain name only.

Setting and getting localStorage with jQuery

You said you are attempting to get the text from a div and store it on local storage.

Please Note: Text and Html are different. In the question you mentioned text. html() will return Html content like <a>example</a>. if you want to get Text content then you have to use text() instead of html() then the result will be example instead of <a>example<a>. Anyway, I am using your terminology let it be Text.

Step 1: get the text from div.

what you did is not get the text from div but set the text to a div.


is actually setting text to div and the output will be a jQuery object. That is why it sets it as [object Object].

To get the text you have to write like this

This will return a string not an object so the result will be Test in your case.

Step 2: set it to local storage.

Your approach is correct and you can write it as


But the preferred approach is

localStorage.setItem(key,value); to set

localStorage.getItem(key); to get.

key and value must be strings.

so in your context code will become

localStorage.content = $('#test').html();

But I don't find any meaning in your code. Because you want to get the text from div and store it on local storage. And again you are reading the same from local storage and set to div. just like a=10; b=a; a=b;

If you are facing any other problems please update your question accordingly.

How to validate a file upload field using Javascript/jquery

I got this from some forum. I hope it will be useful for you.

<script type="text/javascript">
 function validateFileExtension(fld) {
    if(!/(\.bmp|\.gif|\.jpg|\.jpeg)$/i.test(fld.value)) {
        alert("Invalid image file type.");      
        return false;   
    return true; 
 } </script> </head>
 <body> <form ...etc...  onsubmit="return
 validateFileExtension(this.fileField)"> <p> <input type="file"
 name="fileField"  onchange="return validateFileExtension(this)">
 <input type="submit" value="Submit"> </p> </form> </body>

Change the mouse cursor on mouse over to anchor-like style

Assuming your div has an id="myDiv", add the following to your CSS. The cursor: pointer specifies that the cursor should be the same hand icon that is use for anchors (hyperlinks):

CSS to Add

    cursor: pointer;

You can simply add the cursor style to your div's HTML like this:

<div style="cursor: pointer">



If you are determined to use jQuery for this, then add the following line to your $(document).ready() or body onload: (replace myClass with whatever class all of your divs share)

$('.myClass').css('cursor', 'pointer');

Find a private field with Reflection?

Here is some extension methods for simple get and set private fields and properties (properties with setter):

usage example:

    public class Foo
        private int Bar = 5;

    var targetObject = new Foo();
    var barValue = targetObject.GetMemberValue("Bar");//Result is 5
    targetObject.SetMemberValue("Bar", 10);//Sets Bar to 10


    /// <summary>
    /// Extensions methos for using reflection to get / set member values
    /// </summary>
    public static class ReflectionExtensions
        /// <summary>
        /// Gets the public or private member using reflection.
        /// </summary>
        /// <param name="obj">The source target.</param>
        /// <param name="memberName">Name of the field or property.</param>
        /// <returns>the value of member</returns>
        public static object GetMemberValue(this object obj, string memberName)
            var memInf = GetMemberInfo(obj, memberName);

            if (memInf == null)
                throw new System.Exception("memberName");

            if (memInf is System.Reflection.PropertyInfo)
                return memInf.As<System.Reflection.PropertyInfo>().GetValue(obj, null);

            if (memInf is System.Reflection.FieldInfo)
                return memInf.As<System.Reflection.FieldInfo>().GetValue(obj);

            throw new System.Exception();

        /// <summary>
        /// Gets the public or private member using reflection.
        /// </summary>
        /// <param name="obj">The target object.</param>
        /// <param name="memberName">Name of the field or property.</param>
        /// <returns>Old Value</returns>
        public static object SetMemberValue(this object obj, string memberName, object newValue)
            var memInf = GetMemberInfo(obj, memberName);

            if (memInf == null)
                throw new System.Exception("memberName");

            var oldValue = obj.GetMemberValue(memberName);

            if (memInf is System.Reflection.PropertyInfo)
                memInf.As<System.Reflection.PropertyInfo>().SetValue(obj, newValue, null);
            else if (memInf is System.Reflection.FieldInfo)
                memInf.As<System.Reflection.FieldInfo>().SetValue(obj, newValue);
                throw new System.Exception();

            return oldValue;

        /// <summary>
        /// Gets the member info
        /// </summary>
        /// <param name="obj">source object</param>
        /// <param name="memberName">name of member</param>
        /// <returns>instanse of MemberInfo corresponsing to member</returns>
        private static System.Reflection.MemberInfo GetMemberInfo(object obj, string memberName)
            var prps = new System.Collections.Generic.List<System.Reflection.PropertyInfo>();

                                               System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance |
            prps = System.Linq.Enumerable.ToList(System.Linq.Enumerable.Where( prps,i => !ReferenceEquals(i, null)));
            if (prps.Count != 0)
                return prps[0];

            var flds = new System.Collections.Generic.List<System.Reflection.FieldInfo>();

                                            System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance |

            //to add more types of properties

            flds = System.Linq.Enumerable.ToList(System.Linq.Enumerable.Where(flds, i => !ReferenceEquals(i, null)));

            if (flds.Count != 0)
                return flds[0];

            return null;

        private static T As<T>(this object obj)
            return (T)obj;

Will #if RELEASE work like #if DEBUG does in C#?

I know this is an old question, but it might be worth mentioning that you can create your own configurations outside of DEBUG and RELEASE, such as TEST or UAT.

If then on the Build tab of the project properties page you then set the "Conditional compilation symbols" to TEST (for instance) you can then use a construct such as

#if (DEBUG || TEST )
    //Code that will not be executed in RELEASE or UAT

You can use this construct for specific reason such as different clients if you have the need, or even entire Web Methods for instance. We have also used this in the past where some commands have caused issues on specific hardware, so we have a configuration for an app when deployed to hardware X.

TypeError: argument of type 'NoneType' is not iterable

If a function does not return anything, e.g.:

def test():

it has an implicit return value of None.

Thus, as your pick* methods do not return anything, e.g.:

def pickEasy():
    word = random.choice(easyWords)
    word = str(word)
    for i in range(1, len(word) + 1):

the lines that call them, e.g.:

word = pickEasy()

set word to None, so wordInput in getInput is None. This means that:

if guess in wordInput:

is the equivalent of:

if guess in None:

and None is an instance of NoneType which does not provide iterator/iteration functionality, so you get that type error.

The fix is to add the return type:

def pickEasy():
    word = random.choice(easyWords)
    word = str(word)
    for i in range(1, len(word) + 1):
    return word

How to stop/kill a query in postgresql?

What I did is first check what are the running processes by

SELECT * FROM pg_stat_activity WHERE state = 'active';

Find the process you want to kill, then type:

SELECT pg_cancel_backend(<pid of the process>)

This basically "starts" a request to terminate gracefully, which may be satisfied after some time, though the query comes back immediately.

If the process cannot be killed, try:

SELECT pg_terminate_backend(<pid of the process>)

How do I set a cookie on HttpClient's HttpRequestMessage

The accepted answer is the correct way to do this in most cases. However, there are some situations where you want to set the cookie header manually. Normally if you set a "Cookie" header it is ignored, but that's because HttpClientHandler defaults to using its CookieContainer property for cookies. If you disable that then by setting UseCookies to false you can set cookie headers manually and they will appear in the request, e.g.

var baseAddress = new Uri("");
using (var handler = new HttpClientHandler { UseCookies = false })
using (var client = new HttpClient(handler) { BaseAddress = baseAddress })
    var message = new HttpRequestMessage(HttpMethod.Get, "/test");
    message.Headers.Add("Cookie", "cookie1=value1; cookie2=value2");
    var result = await client.SendAsync(message);

Pass Hidden parameters using response.sendRedirect()

TheNewIdiot's answer successfully explains the problem and the reason why you can't send attributes in request through a redirect. Possible solutions:

  1. Using forwarding. This will enable that request attributes could be passed to the view and you can use them in form of ServletRequest#getAttribute or by using Expression Language and JSTL. Short example (reusing TheNewIdiot's answer] code).

    Controller (your servlet)

    request.setAttribute("message", "Hello world");
    RequestDispatcher dispatcher = servletContext().getRequestDispatcher(url);
    dispatcher.forward(request, response);

    View (your JSP)

    Using scriptlets:


    This is just for information purposes. Scriptlets usage must be avoided: How to avoid Java code in JSP files?. Below there is the example using EL and JSTL.

    <c:out value="${message}" />
  2. If you can't use forwarding (because you don't like it or you don't feel it that way or because you must use a redirect) then an option would be saving a message as a session attribute, then redirect to your view, recover the session attribute in your view and remove it from session. Remember to always have your user session with only relevant data. Code example


    //if request is not from HttpServletRequest, you should do a typecast before
    HttpSession session = request.getSession(false);
    //save message in session
    session.setAttribute("helloWorld", "Hello world");


    Again, showing this using scriptlets and then EL + JSTL:

    <c:out value="${sessionScope.message}" />
    <c:remove var="message" scope="session" />

JavaScript closures vs. anonymous functions

After inspecting closely, looks like both of you are using closure.

In your friends case, i is accessed inside anonymous function 1 and i2 is accessed in anonymous function 2 where the console.log is present.

In your case you are accessing i2 inside anonymous function where console.log is present. Add a debugger; statement before console.log and in chrome developer tools under "Scope variables" it will tell under what scope the variable is.

MySQL: Insert datetime into other datetime field

If you don't need the DATETIME value in the rest of your code, it'd be more efficient, simple and secure to use an UPDATE query with a sub-select, something like

UPDATE products SET t=(SELECT f FROM products WHERE id=17) WHERE id=42;

or in case it's in the same row in a single table, just

UPDATE products SET t=f WHERE id=42;

How to return XML in ASP.NET?

You've basically answered anything and everything already, so I'm no sure what the point is here?

FWIW I would use an httphandler - there seems no point in invoking a page lifecycle and having to deal with clipping off the bits of viewstate and session and what have you which don't make sense for an XML doc. It's like buying a car and stripping it for parts to make your motorbike.

And content-type is all important, it's how the requester knows what to do with the response.

Getting the encoding of a Postgres database

If you want to get database encodings:

psql  -U postgres -h somehost --list

You'll see something like:

List of databases
           Name         |  Owner   | Encoding
db1                     | postgres | UTF8

How to get form values in Symfony2 controller

private function getFormDataArray($form)
    $data = [];
    foreach ( $form as $key => $value) {
        $data[$key] = $value->getData();
    return $data;

How do you append to a file?

I always do this,

f = open('filename.txt', 'a')

It's simple, but very useful.

Error: "Input is not proper UTF-8, indicate encoding !" using PHP's simplexml_load_string

After several tries i found htmlentities function works.

$value = htmlentities($value)

What's the difference between __PRETTY_FUNCTION__, __FUNCTION__, __func__?

__func__ is documented in the C++0x standard at section 8.4.1. In this case it's a predefined function local variable of the form:

static const char __func__[] = "function-name ";

where "function name" is implementation specfic. This means that whenever you declare a function, the compiler will add this variable implicitly to your function. The same is true of __FUNCTION__ and __PRETTY_FUNCTION__. Despite their uppercasing, they aren't macros. Although __func__ is an addition to C++0x

g++ -std=c++98 ....

will still compile code using __func__.

__PRETTY_FUNCTION__ and __FUNCTION__ are documented here __FUNCTION__ is just another name for __func__. __PRETTY_FUNCTION__ is the same as __func__ in C but in C++ it contains the type signature as well.

Batch script to find and replace a string in text file without creating an extra output file for storing the modified file

@echo off 
    setlocal enableextensions disabledelayedexpansion

    set "search=%1"
    set "replace=%2"

    set "textFile=Input.txt"

    for /f "delims=" %%i in ('type "%textFile%" ^& break ^> "%textFile%" ') do (
        set "line=%%i"
        setlocal enabledelayedexpansion
        >>"%textFile%" echo(!line:%search%=%replace%!

for /f will read all the data (generated by the type comamnd) before starting to process it. In the subprocess started to execute the type, we include a redirection overwritting the file (so it is emptied). Once the do clause starts to execute (the content of the file is in memory to be processed) the output is appended to the file.

Converting two lists into a matrix

The standard numpy function for what you want is np.column_stack:

>>> np.column_stack(([1, 2, 3], [4, 5, 6]))
array([[1, 4],
       [2, 5],
       [3, 6]])

So with your portfolio and index arrays, doing

np.column_stack((portfolio, index))

would yield something like:

[[portfolio_value1, index_value1],
 [portfolio_value2, index_value2],
 [portfolio_value3, index_value3],

How do you share constants in NodeJS modules?

As an alternative, you can group your "constant" values in a local object, and export a function that returns a shallow clone of this object.

var constants = { FOO: "foo" }

module.exports = function() {
  return Object.assign({}, constants)

Then it doesn't matter if someone re-assigns FOO because it will only affect their local copy.

How do I put variable values into a text string in MATLAB?

I just realized why I was having so much trouble - in MATLAB you can't store strings of different lengths as an array using square brackets. Using square brackets concatenates strings of varying lengths into a single character array.

    >> a=['matlab','is','fun']

a =


>> size(a)

ans =

     1    11

In a character array, each character in a string counts as one element, which explains why the size of a is 1X11.

To store strings of varying lengths as elements of an array, you need to use curly braces to save as a cell array. In cell arrays, each string is treated as a separate element, regardless of length.

>> a={'matlab','is','fun'}

a = 

    'matlab'    'is'    'fun'

>> size(a)

ans =

     1     3

How do I delete NuGet packages that are not referenced by any project in my solution?

One NuGet package can reference another NuGet package. So, please be very careful about inter-package dependencies. I just uninstalled a Google map package and it subsequently uninstalled underlying packages like Newtonsoft, Entity Framework, etc.

So, manually deleting particular package from packages folder would be safer.

How to save a BufferedImage as a File

Create and save a java.awt.image.bufferedImage to file:

import java.awt.image.*;
import javax.imageio.*;
public class Main{
    public static void main(String args[]){
            BufferedImage img = new BufferedImage( 
                500, 500, BufferedImage.TYPE_INT_RGB );

            File f = new File("MyFile.png");
            int r = 5;
            int g = 25;
            int b = 255;
            int col = (r << 16) | (g << 8) | b;
            for(int x = 0; x < 500; x++){
                for(int y = 20; y < 300; y++){
                    img.setRGB(x, y, col);
            ImageIO.write(img, "PNG", f);
        catch(Exception e){


  1. Creates a file called MyFile.png.
  2. Image is 500 by 500 pixels.
  3. Overwrites the existing file.
  4. The color of the image is black with a blue stripe across the top.

How to set a:link height/width with css?

Thanks to RandomUs 1r for this observation:

changing it to display:inline-block; solves that issue. – RandomUs1r May 14 '13 at 21:59

I tried it myself for a top navigation menu bar, as follows:

First style the "li" element as follows:

display: inline-block;
width: 7em;
text-align: center;

Then style the "a"> element as follows:

width: 100%;

Now the navigation links are all equal width with text centered in each link.

Preloading @font-face fonts?

There are a few techniques for "preloading" here:

Mostly tricking the browser into downloading the file as fast as possible..

You can also deliver it as a data-uri, which helps a lot. and also you could hide the page content and show it when its ready.

Trying to get property of non-object - Laravel 5

It happen that after some time we need to run

 'php artisan passport:install --force 

again to generate a key this solved my problem ,

Spring profiles and testing

public class LoginTest extends BaseTest {
    public void exampleTest( ){ 
        // Test

Inherits from a base test class (this example is testng rather than jUnit, but the ActiveProfiles is the same):

@ContextConfiguration(locations = { "classpath:spring-test-config.xml" })
@ActiveProfiles(resolver = MyActiveProfileResolver.class)
public class BaseTest extends AbstractTestNGSpringContextTests { }

MyActiveProfileResolver can contain any logic required to determine which profile to use:

public class MyActiveProfileResolver implements ActiveProfilesResolver {
    public String[] resolve(Class<?> aClass) {
        // This can contain any custom logic to determine which profiles to use
        return new String[] { "exampleProfile" };

This sets the profile which is then used to resolve dependencies required by the test.

jQuery SVG, why can't I addClass?

jQuery does not support the classes of SVG elements. You can get the element directly $(el).get(0) and use classList and add / remove. There is a trick with this too in that the topmost SVG element is actually a normal DOM object and can be used like every other element in jQuery. In my project I created this to take care of what I needed but the documentation provided on the Mozilla Developer Network has a shim that can be used as an alternative.


function addRemoveClass(jqEl, className, addOrRemove) 
  var classAttr = jqEl.attr('class');
  if (!addOrRemove) {
    classAttr = classAttr.replace(new RegExp('\\s?' + className), '');
    jqEl.attr('class', classAttr);
  } else {
    classAttr = classAttr + (classAttr.length === 0 ? '' : ' ') + className;
    jqEl.attr('class', classAttr);

An alternative all tougher is to use D3.js as your selector engine instead. My projects have charts that are built with it so it's also in my app scope. D3 correctly modifies the class attributes of vanilla DOM elements and SVG elements. Though adding D3 for just this case would likely be overkill.'myclass', true);

How to read from stdin with fgets()?

If you want to concatenate the input, then replace printf("%s\n", buffer); with strcat(big_buffer, buffer);. Also create and initialize the big buffer at the beginning: char *big_buffer = new char[BIG_BUFFERSIZE]; big_buffer[0] = '\0';. You should also prevent a buffer overrun by verifying the current buffer length plus the new buffer length does not exceed the limit: if ((strlen(big_buffer) + strlen(buffer)) < BIG_BUFFERSIZE). The modified program would look like this:

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

#define BUFFERSIZE 10
#define BIG_BUFFERSIZE 1024

int main (int argc, char *argv[])
    char buffer[BUFFERSIZE];
    char *big_buffer = new char[BIG_BUFFERSIZE];
    big_buffer[0] = '\0';
    printf("Enter a message: \n");
    while(fgets(buffer, BUFFERSIZE , stdin) != NULL)
        if ((strlen(big_buffer) + strlen(buffer)) < BIG_BUFFERSIZE)
            strcat(big_buffer, buffer);
    return 0;

How to access Spring context in jUnit tests annotated with @RunWith and @ContextConfiguration?

If your test class extends the Spring JUnit classes
(e.g., AbstractTransactionalJUnit4SpringContextTests or any other class that extends AbstractSpringContextTests), you can access the app context by calling the getContext() method.
Check out the javadocs for the package org.springframework.test.

How to get image height and width using java?

You can load jpeg binary data as a file and parse the jpeg headers yourself. The one you are looking for is the 0xFFC0 or Start of Frame header:

Start of frame marker (FFC0)

* the first two bytes, the length, after the marker indicate the number of bytes, including the two length bytes, that this header contains
* P -- one byte: sample precision in bits (usually 8, for baseline JPEG)
* Y -- two bytes
* X -- two bytes
* Nf -- one byte: the number of components in the image
      o 3 for color baseline JPEG images
      o 1 for grayscale baseline JPEG images

* Nf times:
      o Component ID -- one byte
      o H and V sampling factors -- one byte: H is first four bits and V is second four bits
      o Quantization table number-- one byte

The H and V sampling factors dictate the final size of the component they are associated with. For instance, the color space defaults to YCbCr and the H and V sampling factors for each component, Y, Cb, and Cr, default to 2, 1, and 1, respectively (2 for both H and V of the Y component, etc.) in the Jpeg-6a library by the Independent Jpeg Group. While this does mean that the Y component will be twice the size of the other two components--giving it a higher resolution, the lower resolution components are quartered in size during compression in order to achieve this difference. Thus, the Cb and Cr components must be quadrupled in size during decompression.

For more info about the headers check out wikipedia's jpeg entry or I got the above info here.

I used a method similar to the code below which I got from this post at the sun forums:

import java.awt.Dimension;

public class JPEGDim {

public static Dimension getJPEGDimension(File f) throws IOException {
    FileInputStream fis = new FileInputStream(f);

    // check for SOI marker
    if ( != 255 || != 216)
        throw new RuntimeException("SOI (Start Of Image) marker 0xff 0xd8 missing");

    Dimension d = null;

    while ( == 255) {
        int marker =;
        int len = << 8 |;

        if (marker == 192) {

            int height = << 8 |;
            int width = << 8 |;

            d = new Dimension(width, height);

        fis.skip(len - 2);


    return d;

public static void main(String[] args) throws IOException {
    System.out.println(getJPEGDimension(new File(args[0])));


Import CSV file as a pandas DataFrame

To read a CSV file as a pandas DataFrame, you'll need to use pd.read_csv.

But this isn't where the story ends; data exists in many different formats and is stored in different ways so you will often need to pass additional parameters to read_csv to ensure your data is read in properly.

Here's a table listing common scenarios encountered with CSV files along with the appropriate argument you will need to use. You will usually need all or some combination of the arguments below to read in your data.

¦  Scenario                                                ¦  Argument                   ¦  Example                                               ¦
¦  Read CSV with different separator¹                      ¦  sep/delimiter              ¦  read_csv(..., sep=';')                                ¦
¦  Read CSV with tab/whitespace separator                  ¦  delim_whitespace           ¦  read_csv(..., delim_whitespace=True)                  ¦
¦  Fix UnicodeDecodeError while reading²                   ¦  encoding                   ¦  read_csv(..., encoding='latin-1')                     ¦
¦  Read CSV without headers³                               ¦  header and names           ¦  read_csv(..., header=False, names=['x', 'y', 'z'])    ¦
¦  Specify which column to set as the index4               ¦  index_col                  ¦  read_csv(..., index_col=[0])                          ¦
¦  Read subset of columns                                  ¦  usecols                    ¦  read_csv(..., usecols=['x', 'y'])                     ¦
¦  Numeric data is in European format (eg., 1.234,56)      ¦  thousands and decimal      ¦  read_csv(..., thousands='.', decimal=',')             ¦


  1. By default, read_csv uses a C parser engine for performance. The C parser can only handle single character separators. If your CSV has a multi-character separator, you will need to modify your code to use the 'python' engine. You can also pass regular expressions:

    df = pd.read_csv(..., sep=r'\s*\|\s*', engine='python')
  2. UnicodeDecodeError occurs when the data was stored in one encoding format but read in a different, incompatible one. Most common encoding schemes are 'utf-8' and 'latin-1', your data is likely to fit into one of these.

  3. header=False specifies that the first row in the CSV is a data row rather than a header row, and the names=[...] allows you to specify a list of column names to assign to the DataFrame when it is created.

  4. "Unnamed: 0" occurs when a DataFrame with an un-named index is saved to CSV and then re-read after. Instead of having to fix the issue while reading, you can also fix the issue when writing by using

    df.to_csv(..., index=False)

There are other arguments I've not mentioned here, but these are the ones you'll encounter most frequently.

What's the correct way to communicate between controllers in AngularJS?

Regarding the original code - it appears you want to share data between scopes. To share either Data or State between $scope the docs suggest using a service:

  • To run stateless or stateful code shared across controllers — Use angular services instead.
  • To instantiate or manage the life-cycle of other components (for example, to create service instances).

Ref: Angular Docs link here

How to resolve ORA 00936 Missing Expression Error?

This happens every time you insert/ update and you don't use single quotes. When the variable is empty it will result in that error. Fix it by using ''

Assuming the first parameter is an empty variable here is a simple example:


nvl( ,0)


nvl('' ,0)

Put your query into your database software and check it for that error. Generally this is an easy fix

How to trigger a file download when clicking an HTML button or JavaScript

Old thread but it's missing a simple js solution:

let a = document.createElement('a')
a.href = item.url = item.url.split('/').pop()

elasticsearch bool query combine must with OR

$filterQuery = $this->queryFactory->create(QueryInterface::TYPE_BOOL, ['must' => $queries,'should'=>$queriesGeo]);

In must you need to add the query condition array which you want to work with AND and in should you need to add the query condition which you want to work with OR.

You can check this:

Truncate all tables in a MySQL database in one command?

The following MySQL query will itself produce a single query that will truncate all tables in a given database. It bypasses FOREIGN keys:

         'SET FOREIGN_KEY_CHECKS=0; ',
         GROUP_CONCAT(dropTableSql SEPARATOR '; '), '; ',
       ) as dropAllTablesSql
FROM   ( SELECT  Concat('TRUNCATE TABLE ', table_schema, '.', TABLE_NAME) AS dropTableSql
         WHERE   table_schema = 'DATABASE_NAME' ) as queries

Completely removing phpMyAdmin

Try purge

sudo aptitude purge phpmyadmin

Not sure this works with plain old apt-get though

What is the intended use-case for git stash?

You can use the following commands:

  • To save your uncommitted changes

    git stash

  • To list your saved stashes

    git stash list

  • To apply/get back the uncommited changes where x is 0,1,2...

    git stash apply stash@{x}


  • To apply a stash and remove it from the stash list

    git stash pop stash@{x}

  • To apply a stash and keep it in the stash list

    git stash apply stash@{x}

#pragma pack effect

You'd likely only want to use this if you were coding to some hardware (e.g. a memory mapped device) which had strict requirements for register ordering and alignment.

However, this looks like a pretty blunt tool to achieve that end. A better approach would be to code a mini-driver in assembler and give it a C calling interface rather than fumbling around with this pragma.

Restrict varchar() column to specific values?

You want a check constraint.

CHECK constraints determine the valid values from a logical expression that is not based on data in another column. For example, the range of values for a salary column can be limited by creating a CHECK constraint that allows for only data that ranges from $15,000 through $100,000. This prevents salaries from being entered beyond the regular salary range.

You want something like:

    CHECK (Frequency IN ('Daily', 'Weekly', 'Monthly', 'Yearly'))

You can also implement check constraints with scalar functions, as described in the link above, which is how I prefer to do it.

Verifying a specific parameter with Moq

Had one of these as well, but the parameter of the action was an interface with no public properties. Ended up using It.Is() with a seperate method and within this method had to do some mocking of the interface

public interface IQuery
    IQuery SetSomeFields(string info);

void DoSomeQuerying(Action<IQuery> queryThing);

mockedObject.Setup(m => m.DoSomeQuerying(It.Is<Action<IQuery>>(q => MyCheckingMethod(q)));

private bool MyCheckingMethod(Action<IQuery> queryAction)
    var mockQuery = new Mock<IQuery>();
    mockQuery.Setup(m => m.SetSomeFields(It.Is<string>(s => s.MeetsSomeCondition())
    mockQuery.Verify(m => m.SetSomeFields(It.Is<string>(s => s.MeetsSomeCondition(), Times.Once)
    return true

html script src="" triggering redirection with button

First you are linking the file that is here:

<script src="../Script/login.js"> 

Which would lead the website to a file in the Folder Script, but then in the second paragraph you are saying that the folder name is

and also i have onother folder named scripts that contains the the following login.js file

So, this won't work! Because you are not accessing the correct file. To do that please write the code as

<script src="/script/login.js"></script>

Try removing the .. from the beginning of the code too.

This way, you'll reach the js file where the function would run!

Just to make sure:

Just to make sure that the files are attached the HTML DOM, then please open Developer Tools (F12) and in the network workspace note each request that the browser makes to the server. This way you will learn which files were loaded and which weren't, and also why they were not!

Good luck.

Skip first line(field) in loop using CSV file?

There are many ways to skip the first line. In addition to those said by Bakuriu, I would add:

with open(filename, 'r') as f:
    for line in f:


with open(filename,'r') as f:
    lines = f.readlines()[1:]

Tomcat 7 "SEVERE: A child container failed during start"

Tomcat Server fails to start and throws the exception because, inside the section Deployment Descriptor:MyProyect / Servlet Mappings there are mappings that don´t exist. Delete or correct those elements; then starting the server works without problems.

Vim: faster way to select blocks of text in visual mode

} means move cursor to next paragraph. so, use v} to select entire paragraph.

Set variable with multiple values and use IN

Ideally you shouldn't be splitting strings in T-SQL at all.

Barring that change, on older versions before SQL Server 2016, create a split function:

CREATE FUNCTION dbo.SplitStrings
    @List      nvarchar(max), 
    @Delimiter nvarchar(2)
      SELECT CONVERT(xml, N'<root><i>' 
        + REPLACE(@List, @Delimiter, N'</i><i>') 
        + N'</i></root>')
    SELECT Item = LTRIM(RTRIM(i.i.value(N'.',N'nvarchar(max)')))
      FROM x CROSS APPLY x.nodes(N'//root/i') AS i(i)

Now you can say:

DECLARE @Values varchar(1000);

SET @Values = 'A, B, C';

  INNER JOIN dbo.SplitStrings(@Values, ',') AS s
    ON s.Item = foo.myField;

On SQL Server 2016 or above (or Azure SQL Database), it is much simpler and more efficient, however you do have to manually apply LTRIM() to take away any leading spaces:

DECLARE @Values varchar(1000) = 'A, B, C';

    ON LTRIM(s.value) = foo.myField;

Java: Insert multiple rows into MySQL with PreparedStatement

If you can create your sql statement dynamically you can do following workaround:

String myArray[][] = { { "1-1", "1-2" }, { "2-1", "2-2" }, { "3-1", "3-2" } };

StringBuffer mySql = new StringBuffer("insert into MyTable (col1, col2) values (?, ?)");

for (int i = 0; i < myArray.length - 1; i++) {
    mySql.append(", (?, ?)");

myStatement = myConnection.prepareStatement(mySql.toString());

for (int i = 0; i < myArray.length; i++) {
    myStatement.setString(i, myArray[i][1]);
    myStatement.setString(i, myArray[i][2]);

Convert string to datetime

Keep it simple with new Date(string). This should do it...

const s = '01-01-1970 00:03:44';
const d = new Date(s);
console.log(d); // ---> Thu Jan 01 1970 00:03:44 GMT-0500 (Eastern Standard Time)


EDIT: "Code Different" left a valuable comment that MDN no longer recommends using Date as a constructor like this due to browser differences. While the code above works fine in Chrome (v87.0.x) and Edge (v87.0.x), it gives an "Invalid Date" error in Firefox (v84.0.2).

One way to work around this is to make sure your string is in the more universal format of YYYY-MM-DD (obligatory xkcd), e.g., const s = '1970-01-01 00:03:44';, which seems to work in the three major browsers, but this doesn't exactly answer the original question.

python: [Errno 10054] An existing connection was forcibly closed by the remote host

there are many causes such as

  • The network link between server and client may be temporarily going down.
  • running out of system resources.
  • sending malformed data.

To examine the problem in detail, you can use Wireshark.

or you can just re-request or re-connect again.

C - freeing structs

free is not enough, free just marks the memory as unused, the struct data will be there until overwriting. For safety, set the pointer to NULL after free.


if (testPerson) {
    testPerson = NULL;

struct is similar like an array, it is a block of memory. You can access to struct member via its offset. The first struct's member is placed at offset 0 so the address of first struct's member is same as the address of struct.

Right click to select a row in a Datagridview and show a menu to delete it

You can also make this a little simpler by using the following inside the event code:

private void MyDataGridView_MouseDown(object sender, MouseEventArgs e) 
    if (e.Button == MouseButtons.Right)     
        rowToDelete = e.RowIndex;

What does the 'L' in front a string mean in C++?

It's a wchar_t literal, for extended character set. Wikipedia has a little discussion on this topic, and c++ examples.

Sort JavaScript object by key

Maybe a bit more elegant form:

     * Sorts a key-value object by key, maintaining key to data correlations._x000D_
     * @param {Object} src  key-value object_x000D_
     * @returns {Object}_x000D_
var ksort = function ( src ) {_x000D_
      var keys = Object.keys( src ),_x000D_
          target = {};_x000D_
      keys.forEach(function ( key ) {_x000D_
        target[ key ] = src[ key ];_x000D_
      return target;_x000D_
// Usage_x000D_
  b:2  _x000D_

P.S. and the same with ES6+ syntax:

function ksort( src ) {
  const keys = Object.keys( src );
  return keys.reduce(( target, key ) => {
        target[ key ] = src[ key ];
        return target;
  }, {});

What is "android:allowBackup"?

It is privacy concern. It is recommended to disallow users to backup an app if it contains sensitive data. Having access to backup files (i.e. when android:allowBackup="true"), it is possible to modify/read the content of an app even on a non-rooted device.

Solution - use android:allowBackup="false" in the manifest file.

You can read this post to have more information: Hacking Android Apps Using Backup Techniques

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

pycharm running way slow

I found a solution to this problem that works beautifully on Windows, and wanted to share it.

Solutions that didn't work: I have 16GB of RAM and was still having horrible lag. PyCharm takes less than 1GB of RAM for me, so that wasn't the issue. Turning off inspections didn't help at all, and I didn't have any special plugins that I recall. I also tried playing around with CPU affinities for the process, which briefly worked but not really.

What worked beautifully, almost perfectly:

  1. Set PyCharm's CPU priority to Above Normal
  2. Set the CPU priority for Python processes to Below Normal

You can do this manually, but I recommend using a program which will preserve the setting across restarts and for multiple instances. I used Process Hacker: Right click on the process -> Priority -> Set the priority. Then right click again -> Process -> and select "Save for pycharm64.exe" and similarly for python "Save for python.exe." Finally in Process Hacker go to Options and select "Start when I log on." This will make it so that ALL Pycharm and python executables acquire these CPU priorities, even after restarting the program and/or Windows, and no matter how many python instances you launch.

Basically, much of the PyCharm's lag may be due to conflict with other programs. Think about it: Yes PyCharm requires a lot of CPU, but the PyCharm developers aren't stupid. They have probably at least ensured it can run without lag on an empty core. But now you open Chrome and 30 tabs, Fiddler, an FTP program, iTunes, Word, Slack, etc, and they all compete with PyCharm at the same CPU priority level. Whenever the sum of all programs > 100% on a core, you see lag. Switching to Above Normal priority gives PyCharm something closer to the empty core that it was probably tested on.

As for Below Normal on python.exe, basically you don't want to slow your computer down with your own development. Most python programs are essentially "batch" programs, and you probably won't notice the extra time it takes to run. I don't recommend this if you are developing a graphical interactive program.

Accessing Object Memory Address

With ctypes, you can achieve the same thing with

>>> import ctypes
>>> a = (1,2,3)
>>> ctypes.addressof(a)


addressof(C instance) -> integer
Return the address of the C instance internal buffer

Note that in CPython, currently id(a) == ctypes.addressof(a), but ctypes.addressof should return the real address for each Python implementation, if

  • ctypes is supported
  • memory pointers are a valid notion.

Edit: added information about interpreter-independence of ctypes

Using variable in SQL LIKE statement

I had also problem using local variables in LIKE.
Important is to know: how long is variable.
Below, ORDER_NO is 50 characters long, so You can not use: LIKE @ORDER_NO, because in the end will be spaces.
You need to trim right side of the variable first.
Like this:

SELECT @ORDER_NO = 'OR/201910/0012%'


Gradle - Could not find or load main class

For Netbeans 11 users, this works for me:

apply plugin: 'java'
apply plugin: 'application'

// This comes out to package + '.' + mainClassName
mainClassName = 'com.hello.JavaApplication1'

Here generally is my tree:

¦   build.gradle
¦   +---main
¦   ¦   +---java
¦   ¦       +---com
¦   ¦           +---hello
¦   ¦         
¦   ¦
¦   +---test
¦       +---java

"This project is incompatible with the current version of Visual Studio"

I Resolved the issue by deleting the files in the below folder



CSS Resize/Zoom-In effect on Image while keeping Dimensions

You could achieve that simply by wrapping the image by a <div> and adding overflow: hidden to that element:

<div class="img-wrapper">
    <img src="..." />
.img-wrapper {
    display: inline-block; /* change the default display type to inline-block */
    overflow: hidden;      /* hide the overflow */


Also it's worth noting that <img> element (like the other inline elements) sits on its baseline by default. And there would be a 4~5px gap at the bottom of the image.

That vertical gap belongs to the reserved space of descenders like: g j p q y. You could fix the alignment issue by adding vertical-align property to the image with a value other than baseline.

Additionally for a better user experience, you could add transition to the images.

Thus we'll end up with the following:

.img-wrapper img {
    transition: all .2s ease;
    vertical-align: middle;


Clearing input in vuejs form

This solution is only for components

If we toggle(show/hide) components using booleans then data is also removed. No need to clean the form fields.

I usually make components and initialize them using booleans. e.g.

    <button @click="show_create_form = true">Add New Record</button
    <create-form v-if="show_create_form" />

       show_create_form:false //making it false by default
           .then((response) => {
               this.show_create_form= false; //hide it again after success.
               //if you now click on add new record button then it will show you empty form
           }).catch((error) => {

When use clicks on edit button then this boolean becomes true and after successful submit I change it to false again. How can I remove an item from a dropdownlist?

Try this code.

If you can add any item and set value in dropdown then try it.

 dropdown1.Items.Insert(0, new ListItem("---All---", "0"));

You can Removed Item in dropdown then try it.

 ListItem removeItem = dropdown1.Items.FindByText("--Please Select--");

How can I get the timezone name in JavaScript?

Most upvoted answer is probably the best way to get the timezone, however, Intl.DateTimeFormat().resolvedOptions().timeZone returns IANA timezone name by definition, which is in English.

If you want the timezone's name in current user's language, you can parse it from Date's string representation like so:

function getTimezoneName() {_x000D_
  const today = new Date();_x000D_
  const short = today.toLocaleDateString(undefined);_x000D_
  const full = today.toLocaleDateString(undefined, { timeZoneName: 'long' });_x000D_
  // Trying to remove date from the string in a locale-agnostic way_x000D_
  const shortIndex = full.indexOf(short);_x000D_
  if (shortIndex >= 0) {_x000D_
    const trimmed = full.substring(0, shortIndex) + full.substring(shortIndex + short.length);_x000D_
    // by this time `trimmed` should be the timezone's name with some punctuation -_x000D_
    // trim it from both sides_x000D_
    return trimmed.replace(/^[\s,.\-:;]+|[\s,.\-:;]+$/g, '');_x000D_
  } else {_x000D_
    // in some magic case when short representation of date is not present in the long one, just return the long one as a fallback, since it should contain the timezone's name_x000D_
    return full;_x000D_

Tested in Chrome and Firefox.

Ofcourse, this will not work as intended in some of the environments. For example, node.js returns a GMT offset (e.g. GMT+07:00) instead of a name. But I think it's still readable as a fallback.

P.S. Won't work in IE11, just as the Intl... solution.

How to reload / refresh model data from the server programmatically?

Before I show you how to reload / refresh model data from the server programmatically? I have to explain for you the concept of Data Binding. This is an extremely powerful concept that will truly revolutionize the way you develop. So may be you have to read about this concept from this link or this seconde link in order to unterstand how AngularjS work.

now I'll show you a sample example that exaplain how can you update your model from server.

HTML Code:

<div ng-controller="PersonListCtrl">
        <li ng-repeat="person in persons">
            Name: {{}}, Age {{person.age}}
   <button ng-click="updateData()">Refresh Data</button>

So our controller named: PersonListCtrl and our Model named: persons. go to your Controller js in order to develop the function named: updateData() that will be invoked when we are need to update and refresh our Model persons.

Javascript Code:

app.controller('adsController', function($log,$scope,...){


$scope.updateData = function(){
$http.get('/persons').success(function(data) {
       $scope.persons = data;// Update Model-- Line X


Now I explain for you how it work: when user click on button Refresh Data, the server will call to function updateData() and inside this function we will invoke our web service by the function $http.get() and when we have the result from our ws we will affect it to our model (Line X).Dice that affects the results for our model, our View of this list will be changed with new Data.

Outline effect to text

Edit: text-stroke is now fairly mature and implemented in most browsers. It is easier, sharper and more precise. If your browser audience can support it, you should now use text-stroke first, instead of text-shadow.

You can and should do this with just the text-shadow effect without any offsets:

.outline {
    color: #fff;
    text-shadow: #000 0px 0px 1px;
    -webkit-font-smoothing: antialiased;

Why? When you offset multiple shadow effects, you’ll begin to notice ungainly, jagged corners: Shadow effect offsets result in noticeable jagged corners.

Having text-shadow effects in just one position eliminates the offsets, meaning If you feel that’s too thin and would prefer a darker outline instead, no problem — you can repeat the same effect (keeping the same position and blur), several times. Like so:

text-shadow: #000 0px 0px 1px,   #000 0px 0px 1px,   #000 0px 0px 1px,
             #000 0px 0px 1px,   #000 0px 0px 1px,   #000 0px 0px 1px;

Here’s a sample of just one effect (top), and the same effect repeated 14 times (bottom):

Sample text rendered with text-shadow

Also note: Because the lines become so thin, it’s a very good idea to turn off sub-pixel rendering using
-webkit-font-smoothing: antialiased.

How to convert an image to base64 encoding?

You can also do this via curl, just you need a path to an image file and pass it to the function given below..

public static function getImageDataFromUrl($url)
    $urlParts = pathinfo($url);
    $extension = $urlParts['extension'];
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    $response = curl_exec($ch);
    $base64 = 'data:image/' . $extension . ';base64,' . base64_encode($response);
    return $base64;


Javascript : natural sort of alphanumerical strings

This is now possible in modern browsers using localeCompare. By passing the numeric: true option, it will smartly recognize numbers. You can do case-insensitive using sensitivity: 'base'. Tested in Chrome, Firefox, and IE11.

Here's an example. It returns 1, meaning 10 goes after 2:

'10'.localeCompare('2', undefined, {numeric: true, sensitivity: 'base'})

For performance when sorting large numbers of strings, the article says:

When comparing large numbers of strings, such as in sorting large arrays, it is better to create an Intl.Collator object and use the function provided by its compare property. Docs link

var collator = new Intl.Collator(undefined, {numeric: true, sensitivity: 'base'});_x000D_
var myArray = ['1_Document', '11_Document', '2_Document'];_x000D_

Iterate over object keys in node.js

adjust his code:

Object.prototype.each = function(iterateFunc) {
        var counter = 0,
keys = Object.keys(this),
len = keys.length;
        var that = this;
        var next = function() {

            if (counter < len) {
                currentKey = keys[counter++];
                iterateFunc(currentKey, that[currentKey]);

            } else {
                that = counter = keys = currentKey = len = next = undefined;

    ({ property1: 'sdsfs', property2: 'chat' }).each(function(key, val) {
        // do things

How to ping a server only once from within a batch file?

The only thing you need to think about in this case is, in which directory you are on your computer. Your command line window shows C:\users\rei0d\desktop\ as your current directory.

So the only thing you really need to do is:
Remove the desktop by "going up" with the command cd ...

So the complete command would be:

cd ..

java.lang.NoClassDefFoundError: org/apache/juli/logging/LogFactory

This happened to me because I was using a Tomcat 5.5 file with a Tomcat 7 installation. Using the that came with the Tomcat 7 install fixed the problem.

What is the difference between for and foreach?

I prefer the FOR loop in terms of performance. FOREACH is a little slow when you go with more number of items.

If you perform more business logic with the instance then FOREACH performs faster.

Demonstration: I created a list of 10000000 instances and looping with FOR and FOREACH.

Time took to loop:

  • FOREACH -> 53.852ms
  • FOR -> 28.9232ms

Below is the sample code.

class Program

    static void Main(string[] args)
        List<TestClass> lst = new List<TestClass>();
        for (int i = 1; i <= 10000000; i++)
            TestClass obj = new TestClass() {
                ID = i,
                Name = "Name" + i.ToString()

        DateTime start = DateTime.Now;
        foreach (var obj in lst)
            //obj.ID = obj.ID + 1;
            //obj.Name = obj.Name + "1";
        DateTime end = DateTime.Now;
        var first = end.Subtract(start).TotalMilliseconds;

        start = DateTime.Now;
        for (int j = 0; j<lst.Count;j++)
            //lst[j].ID = lst[j].ID + 1;
            //lst[j].Name = lst[j].Name + "1";
        end = DateTime.Now;
        var second = end.Subtract(start).TotalMilliseconds;

public class TestClass
    public long ID { get; set; }
    public string Name { get; set; }

If I uncomment the code inside the loop: Then, time took to loop:

  • FOREACH -> 2564.1405ms
  • FOR -> 2753.0017ms

If you do more business logic with the instance, then FOREACH is recommended. If you are not doing much logic with the instance, then FOR is recommended.

Android check permission for LocationManager

if you are working on dynamic permissions and any permission like ACCESS_FINE_LOCATION,ACCESS_COARSE_LOCATION giving error "cannot resolve method PERMISSION_NAME" in this case write you code with permission name and then rebuild your project this will regenerate the manifest(Manifest.permission) file.

Location of Django logs and errors

Logs are set in your file. A new, default project, looks like this:

# A sample logging configuration. The only tangible logging
# performed by this configuration is to send an email to
# the site admins on every HTTP 500 error when DEBUG=False.
# See for
# more details on how to customize your logging configuration.
    'version': 1,
    'disable_existing_loggers': False,
    'filters': {
        'require_debug_false': {
            '()': 'django.utils.log.RequireDebugFalse'
    'handlers': {
        'mail_admins': {
            'level': 'ERROR',
            'filters': ['require_debug_false'],
            'class': 'django.utils.log.AdminEmailHandler'
    'loggers': {
        'django.request': {
            'handlers': ['mail_admins'],
            'level': 'ERROR',
            'propagate': True,

By default, these don't create log files. If you want those, you need to add a filename parameter to your handlers

    'applogfile': {
        'filename': os.path.join(DJANGO_ROOT, 'APPNAME.log'),
        'maxBytes': 1024*1024*15, # 15MB
        'backupCount': 10,

This will set up a rotating log that can get 15 MB in size and keep 10 historical versions.

In the loggers section from above, you need to add applogfile to the handlers for your application

'loggers': {
        'django.request': {
            'handlers': ['mail_admins'],
            'level': 'ERROR',
            'propagate': True,
        'APPNAME': {
            'handlers': ['applogfile',],
            'level': 'DEBUG',

This example will put your logs in your Django root in a file named APPNAME.log

Java error: Comparison method violates its general contract

It also has something to do with the version of JDK. If it does well in JDK6, maybe it will have the problem in JDK 7 described by you, because the implementation method in jdk 7 has been changed.

Look at this:

Description: The sorting algorithm used by java.util.Arrays.sort and (indirectly) by java.util.Collections.sort has been replaced. The new sort implementation may throw an IllegalArgumentException if it detects a Comparable that violates the Comparable contract. The previous implementation silently ignored such a situation. If the previous behavior is desired, you can use the new system property, java.util.Arrays.useLegacyMergeSort, to restore previous mergesort behaviour.

I don't know the exact reason. However, if you add the code before you use sort. It will be OK.

System.setProperty("java.util.Arrays.useLegacyMergeSort", "true");

PHP Error: Cannot use object of type stdClass as array (array and object issues)

$blog is an object, not an array, so you should access it like so:


How to Fill an array from user input C#?

It made a lot more sense to add this as an answer to arin's code than to keep doing it in comments...

1) Consider using decimal instead of double. It's more likely to give the answer the user expects. See and for reasons why. Basically decimal works a lot closer to how humans think about numbers than double does. Double works more like how computers "naturally" think about numbers, which is why it's faster - but that's not relevant here.

2) For user input, it's usually worth using a method which doesn't throw an exception on bad input - e.g. decimal.TryParse and int.TryParse. These return a Boolean value to say whether or not the parse succeeded, and use an out parameter to give the result. If you haven't started learning about out parameters yet, it might be worth ignoring this point for the moment.

3) It's only a little point, but I think it's wise to have braces round all "for"/"if" (etc) bodies, so I'd change this:

for (int counter = 0; counter < 6; counter++)
    Console.WriteLine("{0,5}{1,8}", counter, array[counter]);

to this:

for (int counter = 0; counter < 6; counter++)
    Console.WriteLine("{0,5}{1,8}", counter, array[counter]);

It makes the block clearer, and means you don't accidentally write:

for (int counter = 0; counter < 6; counter++)
    Console.WriteLine("{0,5}{1,8}", counter, array[counter]);
    Console.WriteLine("----"); // This isn't part of the for loop!

4) Your switch statement doesn't have a default case - so if the user types anything other than "yes" or "no" it will just ignore them and quit. You might want to have something like:

bool keepGoing = true;
while (keepGoing)
    switch (answer)
        case "yes":
            Console.WriteLine("please enter the array index you wish to get the value of it");
            int index = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("The Value of the selected index is:");
            keepGoing = false;

        case "no":
            Console.WriteLine("HAVE A NICE DAY SIR");
            keepGoing = false;

            Console.WriteLine("Sorry, I didn't understand that. Please enter yes or no");

5) When you've started learning about LINQ, you might want to come back to this and replace your for loop which sums the input as just:

// Or decimal, of course, if you've made the earlier selected change
double sum = input.Sum();

Again, this is fairly advanced - don't worry about it for now!

How do I force my .NET application to run as administrator?

The detailed steps are as follow.

  1. Add application manifest file to solution
  2. Change application setting to "app.manifest"
  3. Update tag of "requestedExecutionLevel" to requireAdministrator.

Adding file in Solution

Select Application Manifest File

Select Manifest option

Update Manifest file

Note that using this code you need to turn off the security settings of ClickOnce, for do this, go inside Properties -> Security -> ClickOnce Security

C Linking Error: undefined reference to 'main'

You're not including the C file that contains main() when compiling, so the linker isn't seeing it.

You need to add it:

$ gcc -o runexp runexp.c scd.o data_proc.o -lm -fopenmp

Bootstrap 3 - How to load content in modal body via AJAX?

A simple way to use modals is with eModal!

Ex from github:

  1. Link to eModal.js <script src="//"></script>
  2. use eModal to display a modal for alert, ajax, prompt or confirm

    // Display an alert modal with default title (Attention)

$(document).ready(function () {/* activate scroll spy menu */_x000D_
    var iconPrefix = '.glyphicon-';_x000D_
    $(iconPrefix + 'cloud').click(ajaxDemo);_x000D_
    $(iconPrefix + 'comment').click(alertDemo);_x000D_
    $(iconPrefix + 'ok').click(confirmDemo);_x000D_
    $(iconPrefix + 'pencil').click(promptDemo);_x000D_
    $(iconPrefix + 'screenshot').click(iframeDemo);_x000D_
    ///////////////////* Implementation *///////////////////_x000D_
    // Demos_x000D_
    function ajaxDemo() {_x000D_
        var title = 'Ajax modal';_x000D_
        var params = {_x000D_
            buttons: [_x000D_
               { text: 'Close', close: true, style: 'danger' },_x000D_
               { text: 'New content', close: false, style: 'success', click: ajaxDemo }_x000D_
            size: eModal.size.lg,_x000D_
            title: title,_x000D_
            url: '' + Math.floor((Math.random() * 7) + 1) + '/short/ul/bq/prude/code/decorete'_x000D_
        return eModal_x000D_
            .then(function () { alert('Ajax Request complete!!!!', title) });_x000D_
    function alertDemo() {_x000D_
        var title = 'Alert modal';_x000D_
        return eModal_x000D_
            .alert('You welcome! Want clean code ?', title)_x000D_
            .then(function () { alert('Alert modal is visible.', title); });_x000D_
    function confirmDemo() {_x000D_
        var title = 'Confirm modal callback feedback';_x000D_
        return eModal_x000D_
            .confirm('It is simple enough?', 'Confirm modal')_x000D_
            .then(function (/* DOM */) { alert('Thank you for your OK pressed!', title); })_x000D_
            .fail(function (/*null*/) { alert('Thank you for your Cancel pressed!', title) });_x000D_
    function iframeDemo() {_x000D_
        var title = 'Insiders';_x000D_
        return eModal_x000D_
            .iframe('', title)_x000D_
            .then(function () { alert('iFrame loaded!!!!', title) });_x000D_
    function promptDemo() {_x000D_
        var title = 'Prompt modal callback feedback';_x000D_
        return eModal_x000D_
            .prompt({ size:, message: 'What\'s your name?', title: title })_x000D_
            .then(function (input) { alert({ message: 'Hi ' + input + '!', title: title, imgURI: '' }) })_x000D_
            .fail(function (/**/) { alert('Why don\'t you tell me your name?', title); });_x000D_
<script src=""></script>_x000D_
<script src=""></script>_x000D_
<script src=""></script>_x000D_
<link href="" rel="stylesheet" >_x000D_
<link href="http//" rel="stylesheet">_x000D_
<div class="row" itemprop="about">_x000D_
 <div class="col-sm-1 text-center"></div>_x000D_
 <div class="col-sm-2 text-center">_x000D_
  <div class="row">_x000D_
   <div class="col-sm-10 text-center">_x000D_
    <p>You must get the message from a remote server? No problem!</p>_x000D_
    <i class="glyphicon glyphicon-cloud fa-5x pointer" title="Try me!"></i>_x000D_
 <div class="col-sm-2 text-center">_x000D_
  <div class="row">_x000D_
   <div class="col-sm-10 text-center">_x000D_
    <p>Traditional alert box. Using only text or a lot of magic!?</p>_x000D_
    <i class="glyphicon glyphicon-comment fa-5x pointer" title="Try me!"></i>_x000D_
 <div class="col-sm-2 text-center">_x000D_
  <div class="row">_x000D_
   <div class="col-sm-10 text-center">_x000D_
    <p>Get an okay from user, has never been so simple and clean!</p>_x000D_
    <i class="glyphicon glyphicon-ok fa-5x pointer" title="Try me!"></i>_x000D_
 <div class="col-sm-2 text-center">_x000D_
  <div class="row">_x000D_
   <div class="col-sm-10  text-center">_x000D_
    <p>Do you have a question for the user? We take care of it...</p>_x000D_
    <i class="glyphicon glyphicon-pencil fa-5x pointer" title="Try me!"></i>_x000D_
 <div class="col-sm-2 text-center">_x000D_
  <div class="row">_x000D_
   <div class="col-sm-10  text-center">_x000D_
    <p>IFrames are hard to deal with it? We don't think so!</p>_x000D_
    <i class="glyphicon glyphicon-screenshot fa-5x pointer" title="Try me!"></i>_x000D_
 <div class="col-sm-1 text-center"></div>_x000D_

How to encrypt and decrypt String with my passphrase in Java (Pc not mobile platform)?

package com.example;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
public class StrongAES 
    public void run() 
            String text = "Hello World";
            String key = "Bar12345Bar12345"; // 128 bit key
            // Create key and cipher
            Key aesKey = new SecretKeySpec(key.getBytes(), "AES");
            Cipher cipher = Cipher.getInstance("AES");
            // encrypt the text
            cipher.init(Cipher.ENCRYPT_MODE, aesKey);
            byte[] encrypted = cipher.doFinal(text.getBytes());
            System.err.println(new String(encrypted));
            // decrypt the text
            cipher.init(Cipher.DECRYPT_MODE, aesKey);
            String decrypted = new String(cipher.doFinal(encrypted));
        catch(Exception e) 
    public static void main(String[] args) 
        StrongAES app = new StrongAES();;

Remove part of a string

Here's the strsplit solution if s is a vector:

> s <- c("TGAS_1121", "MGAS_1432")
> s1 <- sapply(strsplit(s, split='_', fixed=TRUE), function(x) (x[2]))
> s1
[1] "1121" "1432"

How can I return camelCase JSON serialized by JSON.NET from ASP.NET MVC controller methods?

I think this is the simple answer you are looking for. It's from Shawn Wildermuth's blog:

// Add MVC services to the services container.
  .AddJsonOptions(opts =>
    opts.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();

Can I store images in MySQL

You will need to store the image in the database as a BLOB.

you will want to create a column called PHOTO in your table and set it as a mediumblob.

Then you will want to get it from the form like so:

    $data = file_get_contents($_FILES['photo']['tmp_name']);

and then set the column to the value in $data.

Of course, this is bad practice and you would probably want to store the file on the system with a name that corresponds to the users account.

Python constructor and default value

I would try:

self.wordList = list(wordList)

to force it to make a copy instead of referencing the same object.

JSON character encoding - is UTF-8 well-supported by browsers or should I use numeric escape sequences?

I had a similar problem with é char... I think the comment "it's possible that the text you're feeding it isn't UTF-8" is probably close to the mark here. I have a feeling the default collation in my instance was something else until I realized and changed to utf8... problem is the data was already there, so not sure if it converted the data or not when i changed it, displays fine in mysql workbench. End result is that php will not json encode the data, just returns false. Doesn't matter what browser you use as its the server causing my issue, php will not parse the data to utf8 if this char is present. Like i say not sure if it is due to converting the schema to utf8 after data was present or just a php bug. In this case use json_encode(utf8_encode($string));

How to get Maven project version to the bash command line

This is the cleanest solution there is:

mvn org.apache.maven.plugins:maven-help-plugin:3.2.0:evaluate \
-Dexpression=project.version -q -DforceStdout


  • This works fine on all operating systems and all shells.
  • No need for any external tools!
  • [important] This works even if project version is inherited from parent pom.xml


  • maven-help-plugin version 3.2.0 (and above) has forceStdout option. You may replace 3.2.0 in above command with a newer version from the list of available versions of mvn-help-plugin from artifactory, if available.
  • Option -q suppresses verbose messages ([INFO], [WARN] etc.)

Alternatively, you can add this entry in your pom.xml, under plugins section:


and then run above command compactly as follows:

mvn help:evaluate -Dexpression=project.groupId -q -DforceStdout

If you want to fetch groupId and artifactId as well, check this answer.

Android Studio : How to uninstall APK (or execute adb command) automatically before Run or Debug?

This command with --user 0 do the job:

adb uninstall --user 0 <package_name>

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

If you are searching for the index of the last occurrence of myvalue in mylist:

len(mylist) - mylist[::-1].index(myvalue) - 1

How to access ssis package variables inside script component

First List the Variable that you want to use them in Script task at ReadOnlyVariables in the Script task editor and Edit the Script

To use your ReadOnlyVariables in script code

String codeVariable = Dts.Variables["User::VariableNameinSSIS"].Value.ToString();

this line of code will treat the ssis package variable as a string.

HTTP POST using JSON in Java

You can make use of Gson library to convert your java classes to JSON objects.

Create a pojo class for variables you want to send as per above Example



class pojo1
   String name;
   String age;
   //generate setter and getters

once you set the variables in pojo1 class you can send that using the following code

String       postUrl       = "";// put in your url
Gson         gson          = new Gson();
HttpClient   httpClient    = HttpClientBuilder.create().build();
HttpPost     post          = new HttpPost(postUrl);
StringEntity postingString = new StringEntity(gson.toJson(pojo1));//gson.tojson() converts your pojo to json
post.setHeader("Content-type", "application/json");
HttpResponse  response = httpClient.execute(post);

and these are the imports

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;

and for GSON


How can I send an xml body using requests library?

Pass in the straight XML instead of a dictionary.

How to make a parent div auto size to the width of its children divs

The parent div (I assume the outermost div) is display: block and will fill up all available area of its container (in this case, the body) that it can. Use a different display type -- inline-block is probably what you are going for:

Use Excel pivot table as data source for another Pivot Table

Personally, I got around this in a slightly different way - I had a pivot table querying an SQL server source and I was using the timeline slicer to restrict the results to a date range - I then wanted to summarise the pivot results in another table.

I selected the 'source' pivot table and created a named range called 'SourcePivotData'.

Create your summary pivot tables using the named range as a source.

In the worksheet events for the source pivot table, I put the following code:

Private Sub Worksheet_PivotTableUpdate(ByVal Target As PivotTable)

'Update the address of the named range
ThisWorkbook.Names("SourcePivotData").RefersTo = "='" & Target.TableRange1.Worksheet.Name & "'!" & Target.TableRange1.AddressLocal

'Refresh any pivot tables that use this as a source
Dim pt As PivotTable
Application.DisplayAlerts = False
For Each pt In Sheet2.PivotTables
Next pt
Application.DisplayAlerts = True

End Sub

Works nicely for me! :)

How to get controls in WPF to fill available space?

There are also some properties you can set to force a control to fill its available space when it would otherwise not do so. For example, you can say:


... to force the contents of a control to stretch horizontally. Or you can say:


... to force the control itself to stretch horizontally to fill its parent.

How to decode a Base64 string?

There are no PowerShell-native commands for Base64 conversion - yet (as of PowerShell [Core] 7.1), but adding dedicated cmdlets has been suggested.
For now, direct use of .NET is needed.


  • Base64 encoding is an encoding of binary data using bytes whose values are constrained to a well-defined 64-character subrange of the ASCII character set representing printable characters, devised at a time when sending arbitrary bytes was problematic, especially with the high bit set (byte values > 0x7f).

  • Therefore, you must always specify explicitly what character encoding the Base64 bytes do / should represent.


  • on converting TO Base64, you must first obtain a byte representation of the string you're trying to encode using the character encoding the consumer of the Base64 string expects.

  • on converting FROM Base64, you must interpret the resultant array of bytes as a string using the same encoding that was used to create the Base64 representation.



  • The following examples convert to and from UTF-8 encoded strings:

  • To convert to and from UTF-16LE ("Unicode") instead, substitute [Text.Encoding]::Unicode for [Text.Encoding]::UTF8

Convert TO Base64:

PS> [Convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes('Motörhead'))

Convert FROM Base64:

PS> [Text.Encoding]::Utf8.GetString([Convert]::FromBase64String('TW90w7ZyaGVhZA=='))

Using margin:auto to vertically-align a div

I think you can fix that with Flexbox

.black {
  height : 200px;
  width : 200px;
  background-color : teal;
  border: 5px solid rgb(0, 53, 53);
  /* This is the important part */
  display : flex;
  justify-content: center;
  align-items: center;

.message {
  background-color :  rgb(119, 128, 0);
  border: 5px solid rgb(0, 53, 53);
  height : 50%;
  width : 50%;
  padding : 5px;
<div class="black">
    <div class="message">
        This is a popup message.

How to print GETDATE() in SQL Server with milliseconds in time?

This is equivalent to new Date().getTime() in JavaScript :

Use the below statement to get the time in seconds.

SELECT  cast(DATEDIFF(s, '1970-01-01 00:00:00.000', '2016-12-09 16:22:17.897' ) as bigint)

Use the below statement to get the time in milliseconds.

SELECT  cast(DATEDIFF(s, '1970-01-01 00:00:00.000', '2016-12-09 16:22:17.897' ) as bigint)  * 1000

In Bash, how do I add a string after each line in a file?

I prefer using awk. If there is only one column, use $0, else replace it with the last column.

One way,

awk '{print $0, "string to append after each line"}' file > new_file

or this,

awk '$0=$0"string to append after each line"' file > new_file

Extract matrix column values by matrix column name

Yes. But place your "test" after the comma if you want the column...

> A <- matrix(sample(1:12,12,T),ncol=4)

> rownames(A) <- letters[1:3]

> colnames(A) <- letters[11:14]
> A[,"l"]
 a  b  c 
 6 10  1 

see also help(Extract)

How do I fix a "Performance counter registry hive consistency" when installing SQL Server R2 Express?

Well guys, the solution to the problem is the following:

  1. click in: Start
  2. write the word: ejecut
  3. After, write: regedit
  4. Open the directory: HKEY_LOCAL_MACHINE
  6. Microsoft
  7. Windows NT
  8. CurrentVersion
  9. Perflib
  10. Check the following things:

1) Folder 00A: 2) Counter: the last number 3) Help: the last number

   Folder Perflib:
   Last Counter: 00A folder´s Counter 
   Last Help: 00A folder´s Help

Ready, verify the same number in both. success

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

in your location block you can do:

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

which will tell ngingx to look for a file with the exact name given first, and if none such file is found it will try uri/index.html. So if a request for comes it it would look for an exact file match first, and not finding that would then check for index.html

How to express a NOT IN query with ActiveRecord/Rails?

If someone want to use two or more conditions, you can do that:

your_array = [1,2,3,4]
your_string = "SOMETHING"

YourModel.where('variable1 NOT IN (?) AND variable2=(?)',Array.wrap(your_array),your_string)

How can I prevent the backspace key from navigating back?

Have you tried the very simple solution of just adding the following attribute to your read only text field:

onkeydown="return false;"

This will keep the browser from going back in history when the Backspace key is pressed in a read only text field. Maybe I am missing your true intent, but seems like this would be the simplest solution to your issue.

How to set thymeleaf th:field value from other variable

So what you need to do is replace th:field with th:name and add th:value, th:value will have the value of the variable you're passing across.

<div class="col-auto">
        <input type="text" th:value="${}" th:name="clientName" 
        class="form control">

Importing two classes with same name. How to handle?

You can import one of them using import. For all other similar class , you need to specify Fully qualified class names. Otherwise you will get compilation error.


import java.util.Date;

class Test{

  public static void main(String [] args){

    // your own date
    my.own.Date myOwndate ;

    // util.Date
    Date utilDate;

Why can't I use Docker CMD multiple times to run multiple services?

The official docker answer to Run multiple services in a container.

It explains how you can do it with an init system (systemd, sysvinit, upstart) , a script (CMD ./ or a supervisor like supervisord.

The && workaround can work only for services that starts in background (daemons) or that will execute quickly without interaction and release the prompt. Doing this with an interactive service (that keeps the prompt) and only the first service will start.

How to display loading message when an iFrame is loading?

Here's a quick solution for most of the cases:


.iframe-loading { 
    background:url(/img/loading.gif) center center no-repeat; 

You can use an animated loading GIF if you want to,


<div class="iframe-loading">
    <iframe src="http://your_iframe_url_goes_here"  onload="$('.iframe-loading').css('background-image', 'none');"></iframe>

Using the onload event you can remove the loading image after the source page is loaded inside your iframe.

If you are not using jQuery, just put an id into the div and replace this part of code:

$('.iframe-loading').css('background-image', 'none');

by something like this:

document.getElementById("myDivName").style.backgroundImage = "none";

All the best!

Insert images to XML file

Here's some code taken from Kirk Evans Blog that demonstrates how to encode an image in C#;

//Load the picture from a file
Image picture = Image.FromFile(@"c:\temp\test.gif");

//Create an in-memory stream to hold the picture's bytes
System.IO.MemoryStream pictureAsStream = new System.IO.MemoryStream();
picture.Save(pictureAsStream, System.Drawing.Imaging.ImageFormat.Gif);

//Rewind the stream back to the beginning
pictureAsStream.Position = 0;
//Get the stream as an array of bytes
byte[] pictureAsBytes = pictureAsStream.ToArray();

//Create an XmlTextWriter to write the XML somewhere... here, I just chose
//to stream out to the Console output stream
System.Xml.XmlTextWriter writer = new System.Xml.XmlTextWriter(Console.Out);

//Write the root element of the XML document and the base64 encoded data
writer.WriteStartElement("w", "binData",

writer.WriteBase64(pictureAsBytes, 0, pictureAsBytes.Length);


What's an easy way to read random line from a file in Unix command line?

sort --random-sort $FILE | head -n 1

(I like the shuf approach above even better though - I didn't even know that existed and I would have never found that tool on my own)

jQuery and TinyMCE: textarea value doesn't submit

You can also simply use the jQuery plugin and package for TinyMCE it sorts out these kinds of issues.

IsNothing versus Is Nothing

VB is full of things like that trying to make it both "like English" and comfortable for people who are used to languages that use () and {} a lot. And on the other side, as you already probably know, most of the time you can use () with function calls if you want to, but don't have to.

I prefer IsNothing()... but I use C and C#, so that's just what is comfortable. And I think it's more readable. But go with whatever feels more comfortable to you.

JPA getSingleResult() or null

I achieved this by getting a result list then checking if it is empty

public boolean exist(String value) {
        List<Object> options = getEntityManager().createNamedQuery("AppUsers.findByEmail").setParameter('email', value).getResultList();
        return !options.isEmpty();

It is so annoying that getSingleResult() throws exceptions


  1. NoResultException - if there is no result
  2. NonUniqueResultException - if more than one result and some other exception that you can get more info on from their documentation

How to colorize diff on the command line?

And for those occasions when a yum install colordiff or an apt-get install colordiff is not an option due to some insane constraint beyond your immediate control, or you're just feeling crazy, you can re-invent the wheel with a line of sed:

sed 's/^-/\x1b[41m-/;s/^+/\x1b[42m+/;s/^@/\x1b[34m@/;s/$/\x1b[0m/'

Throw that in a shell script and pipe unified diff output through it.

It makes hunk markers blue and highlights new/old filenames and added/removed lines in green and red background, respectively.1 And it will make trailing space2 changes more readily apparent than colordiff can.

1 Incidentally, the reason for highlighting the filenames the same as the modified lines is that to correctly differentiate between the filenames and the modified lines requires properly parsing the diff format, which is not something to tackle with a regex. Highlighting them the same works "well enough" visually and makes the problem trivial. That said, there are some interesting subtleties.

2 But not trailing tabs. Apparently tabs don't get their background set, at least in my xterm. It does make tab vs space changes stand out a bit though.

Inserting NOW() into Database with CodeIgniter's Active Record

According to the source code of codeigniter, the function set is defined as:

public function set($key, $value = '', $escape = TRUE)
    $key = $this->_object_to_array($key);

    if ( ! is_array($key))
        $key = array($key => $value);

    foreach ($key as $k => $v)
        if ($escape === FALSE)
            $this->ar_set[$this->_protect_identifiers($k)] = $v;
            $this->ar_set[$this->_protect_identifiers($k, FALSE, TRUE)] = $this->escape($v);

    return $this;

Apparently, if $key is an array, codeigniter will simply ignore the second parameter $value, but the third parameter $escape will still work throughout the iteration of $key, so in this situation, the following codes work (using the chain method):

    'name' => $name ,
    'email' => $email,
    'time' => 'NOW()'), '', FALSE)->insert('mytable');

However, this will unescape all the data, so you can break your data into two parts:

    'name' => $name ,
    'email' => $email))->set(array('time' => 'NOW()'), '', FALSE)->insert('mytable');

I need to convert an int variable to double

Converting to double can be done by casting an int to a double:

You can convert an int to a double by using this mechnism like so:

int i = 3; // i is 3
double d = (double) i; // d = 3.0

Alternative (using Java's automatic type recognition):

double d = 1.0 * i; // d = 3.0

Implementing this in your code would be something like:

double firstSolution = ((double)(b1 * a22 - b2 * a12) / (double)(a11 * a22 - a12 * a21));
double secondSolution = ((double)(b2 * a11 - b1 * a21) / (double)(a11 * a22 - a12 * a21));

Alternatively you can use a hard-parameter of type double (1.0) to have java to the work for you, like so:

double firstSolution = ((1.0 * (b1 * a22 - b2 * a12)) / (1.0 * (a11 * a22 - a12 * a21)));
double secondSolution = ((1.0 * (b2 * a11 - b1 * a21)) / (1.0 * (a11 * a22 - a12 * a21)));

Good luck.

Why does the C++ STL not provide any "tree" containers?

Probably for the same reason that there is no tree container in boost. There are many ways to implement such a container, and there is no good way to satisfy everyone who would use it.

Some issues to consider:

  • Are the number of children for a node fixed or variable?
  • How much overhead per node? - ie, do you need parent pointers, sibling pointers, etc.
  • What algorithms to provide? - different iterators, search algorithms, etc.

In the end, the problem ends up being that a tree container that would be useful enough to everyone, would be too heavyweight to satisfy most of the people using it. If you are looking for something powerful, Boost Graph Library is essentially a superset of what a tree library could be used for.

Here are some other generic tree implementations:

How can I create and style a div using JavaScript?

create div with id name

var divCreator=function (id){

add text to div

var textAdder = function(id, text) {
target = document.getElementById(id)

test code

textAdder("div1", "this is paragraph 1");


this is paragraph 1

Using number_format method in Laravel

Here's another way of doing it, add in app\Providers\AppServiceProvider.php

use Illuminate\Support\Str;


public function boot()
    // add Str::currency macro
    Str::macro('currency', function ($price)
        return number_format($price, 2, '.', '\'');

Then use Str::currency() in the blade templates or directly in the Expense model.

@foreach ($Expenses as $Expense)
        <td>{{{ $Expense->type }}}</td>
        <td>{{{ $Expense->narration }}}</td>
        <td>{{{ Str::currency($Expense->price) }}}</td>
        <td>{{{ $Expense->quantity }}}</td>
        <td>{{{ Str::currency($Expense->amount) }}}</td>                                                            

TSQL Pivot without aggregate function

Ok, sorry for the poor question. gbn got me on the right track. This is what I was looking for in an answer.

SELECT [FirstName], [MiddleName], [LastName], [Date] 
FROM #temp 
(   MIN([Data]) 
    FOR [DBColumnName] IN ([FirstName], [MiddleName], [LastName], [Date]) 
)AS p

Then I had to use a while statement and build the above statement as a varchar and use dynmaic sql.

Using something like this

SET @fullsql = @fullsql + 'SELECT ' + REPLACE(REPLACE(@fulltext,'(',''),')','')
SET @fullsql = @fullsql + 'FROM #temp '
SET @fullsql = @fullsql + 'PIVOT'
SET @fullsql = @fullsql + '('
SET @fullsql = @fullsql + ' MIN([Data])'
SET @fullsql = @fullsql + ' FOR [DBColumnName] IN '+@fulltext
SET @fullsql = @fullsql + ')'
SET @fullsql = @fullsql + 'AS p'

EXEC (@fullsql)

Having a to build @fulltext using a while loop and select the distinct column names out of the table. Thanks for the answers.