Programs & Examples On #Overload resolution

Overload resolution is a language mechanism to select among several viable function overloads. Its rules are intricate and often surprising, even for experienced users.

Convert a number range to another range, maintaining ratio

That's a simple linear conversion.

new_value = ( (old_value - old_min) / (old_max - old_min) ) * (new_max - new_min) + new_min

So converting 10000 on the scale of -16000 to 16000 to a new scale of 0 to 100 yields:

old_value = 10000
old_min = -16000
old_max = 16000
new_min = 0
new_max = 100

new_value = ( ( 10000 - -16000 ) / (16000 - -16000) ) * (100 - 0) + 0
          = 81.25

fatal error: iostream.h no such file or directory

Using standard C++ calling (note that you should use namespace std for cout or add using namespace std;)

#include <iostream>

int main()
    std::cout<<"Hello World!\n";
    return 0;

How do I escape ampersands in batch files?

For special characters like '&' you can surround the entire expression with quotation marks

set "url=https://url?retry=true&w=majority"

Angular-Material DateTime Picker Component?

I recommend you to checkout @angular-material-components/datetime-picker. This is a DatetimePicker like @angular/material Datepicker by adding support for choosing time.

enter image description here

How do I revert back to an OpenWrt router configuration?

If you enabled it as a DHCP client then your router should get an IP address from a DHCP server. If you connect your router on a net with a DHCP server you should reach your router's administrator page on the IP address assigned by the DHCP.

Get the first N elements of an array?

if you want to get the first N elements and also remove it from the array, you can use array_splice() (note the 'p' in "splice"):

use it like so: $array_without_n_elements = array_splice($old_array, 0, N)

How to include "zero" / "0" results in COUNT aggregate?

To change even less on your original query, you can turn your join into a RIGHT join

SELECT person.person_id, COUNT(appointment.person_id) AS "number_of_appointments"
FROM appointment
RIGHT JOIN person ON person.person_id = appointment.person_id
GROUP BY person.person_id;

This just builds on the selected answer, but as the outer join is in the RIGHT direction, only one word needs to be added and less changes. - Just remember that it's there and can sometimes make queries more readable and require less rebuilding.

Android customized button; changing text color

Changing text color of button

Because this method is now deprecated


I use the following:

button.setTextColor(ContextCompat.getColor(mContext, R.color.your_color));

How to write html code inside <?php ?>, I want write html code within the PHP script so that it can be echoed from Backend

You can drop in and out of the PHP context using the <?php and ?> tags. For example...

$array = array(1, 2, 3, 4);

<?php foreach ($array as $num) : ?>
<tr><td><?= htmlspecialchars($num) ?></td></tr>
<?php endforeach ?>

Also see Alternative syntax for control structures

How to add a jar in External Libraries in android studio

The GUI based approach would be to add an additional module in your project.

  1. From the File menu select Project Structure and click on the green plus icon on the top left.
  2. The new Module dialog pops
  3. From the phone and tablet application group select the "Import JAR or AAR package" option and click next.
  4. Follow the steps to create a new module that contains your JAR file.
  5. Click on the entry that corresponds to your main project and select the dependencies tab.
  6. Add a dependency to the module that you created in step 4.

One final piece of advice. Make sure that the JAR file you include is build with at most JDK 1.7. Many problems relating to error message " bad class file magic (cafebabe) or version (0034.0000)" root straight to this :0.

Why are Python lambdas useful?

First congrats that managed to figure out lambda. In my opinion this is really powerful construct to act with. The trend these days towards functional programming languages is surely an indicator that it neither should be avoided nor it will be redefined in the near future.

You just have to think a little bit different. I'm sure soon you will love it. But be careful if you deal only with python. Because the lambda is not a real closure, it is "broken" somehow: pythons lambda is broken

Dropping Unique constraint from MySQL table

while dropping unique key we use index

DROP INDEX  unique_address;

What is the difference between user variables and system variables?

Environment variables are 'evaluated' (ie. they are attributed) in the following order:

  1. System variables
  2. Variables defined in autoexec.bat
  3. User variables

Every process has an environment block that contains a set of environment variables and their values. There are two types of environment variables: user environment variables (set for each user) and system environment variables (set for everyone). A child process inherits the environment variables of its parent process by default.

Programs started by the command processor inherit the command processor's environment variables.

Environment variables specify search paths for files, directories for temporary files, application-specific options, and other similar information. The system maintains an environment block for each user and one for the computer. The system environment block represents environment variables for all users of the particular computer. A user's environment block represents the environment variables the system maintains for that particular user, including the set of system environment variables.

How can I recover the return value of a function passed to multiprocessing.Process?

The pebble package has a nice abstraction leveraging multiprocessing.Pipe which makes this quite straightforward:

from pebble import concurrent

def function(arg, kwarg=0):
    return arg + kwarg

future = function(1, kwarg=1)


Example from:

Oracle date "Between" Query

You need to convert those to actual dates instead of strings, try this:

WHERE start_date BETWEEN TO_DATE('2010-01-15','YYYY-MM-DD') AND TO_DATE('2010-01-17', 'YYYY-MM-DD');

Edited to deal with format as specified:

WHERE start_date BETWEEN TO_DATE('15-JAN-10','DD-MON-YY') AND TO_DATE('17-JAN-10','DD-MON-YY');

How to delete columns that contain ONLY NAs?

It seeems like you want to remove ONLY columns with ALL NAs, leaving columns with some rows that do have NAs. I would do this (but I am sure there is an efficient vectorised soution:

#set seed for reproducibility
set.seed <- 103
df <- data.frame( id = 1:10 , nas = rep( NA , 10 ) , vals = sample( c( 1:3 , NA ) , 10 , repl = TRUE ) )
#      id nas vals
#   1   1  NA   NA
#   2   2  NA    2
#   3   3  NA    1
#   4   4  NA    2
#   5   5  NA    2
#   6   6  NA    3
#   7   7  NA    2
#   8   8  NA    3
#   9   9  NA    3
#   10 10  NA    2

#Use this command to remove columns that are entirely NA values, it will elave columns where only some vlaues are NA
df[ , ! apply( df , 2 , function(x) all( ) ]
#      id vals
#   1   1   NA
#   2   2    2
#   3   3    1
#   4   4    2
#   5   5    2
#   6   6    3
#   7   7    2
#   8   8    3
#   9   9    3
#   10 10    2

If you find yourself in the situation where you want to remove columns that have any NA values you can simply change the all command above to any.

Skipping Iterations in Python

For this specific use-case using try..except..else is the cleanest solution, the else clause will be executed if no exception was raised.

NOTE: The else clause must follow all except clauses

for i in iterator:
        # Do something.
        # Handle exception
        # Continue doing something

Gradle DSL method not found: 'runProguard'

enter image description hereIf you are using version 0.14.0 or higher of the gradle plugin, you should replace "runProguard" with "minifyEnabled" in your build.gradle files.

runProguard was renamed to minifyEnabled in version 0.14.0. For more info, See Android Build System

How to emulate GPS location in the Android Emulator?

In Mac, Linux or Cygwin:

echo 'geo fix -99.133333 19.43333 2202' | nc localhost 5554

That will put you in Mexico City. Change your longitude/latitude/altitude accordingly. That should be enough if you are not interested in nmea.

Conditional WHERE clause with CASE statement in Oracle

You can write the where clause as:

where (case when (:stateCode = '') then (1)
            when (:stateCode != '') and (vw.state_cd in (:stateCode)) then 1
            else 0)
       end) = 1;

Alternatively, remove the case entirely:

where (:stateCode = '') or
      ((:stateCode != '') and vw.state_cd in (:stateCode));

Or, even better:

where (:stateCode = '') or vw.state_cd in (:stateCode)

Adding multiple class using ng-class

With multiple conditions

<div ng-class="{'class1' : con1 || can2, 'class2' : con3 && con4}">
Hello World!

C++ Array of pointers: delete or delete []?

The second one is correct under the circumstances (well, the least wrong, anyway).

Edit: "least wrong", as in the original code shows no good reason to be using new or delete in the first place, so you should probably just use:

std::vector<Monster> monsters;

The result will be simpler code and cleaner separation of responsibilities.

Numpy: Get random set of rows from 2D array

If you need the same rows but just a random sample then,

import random
new_array = random.sample(old_array,x)

Here x, has to be an 'int' defining the number of rows you want to randomly pick.

Combine several images horizontally with Python

Based on DTing's answer I created a function that is easier to use:

from PIL import Image

def append_images(images, direction='horizontal',
                  bg_color=(255,255,255), aligment='center'):
    Appends images in horizontal/vertical direction.

        images: List of PIL images
        direction: direction of concatenation, 'horizontal' or 'vertical'
        bg_color: Background color (default: white)
        aligment: alignment mode if images need padding;
           'left', 'right', 'top', 'bottom', or 'center'

        Concatenated image as a new PIL image object.
    widths, heights = zip(*(i.size for i in images))

    if direction=='horizontal':
        new_width = sum(widths)
        new_height = max(heights)
        new_width = max(widths)
        new_height = sum(heights)

    new_im ='RGB', (new_width, new_height), color=bg_color)

    offset = 0
    for im in images:
        if direction=='horizontal':
            y = 0
            if aligment == 'center':
                y = int((new_height - im.size[1])/2)
            elif aligment == 'bottom':
                y = new_height - im.size[1]
            new_im.paste(im, (offset, y))
            offset += im.size[0]
            x = 0
            if aligment == 'center':
                x = int((new_width - im.size[0])/2)
            elif aligment == 'right':
                x = new_width - im.size[0]
            new_im.paste(im, (x, offset))
            offset += im.size[1]

    return new_im

It allows choosing a background color and image alignment. It's also easy to do recursion:

images = map(, ['hummingbird.jpg', 'tiger.jpg', 'monarch.png'])

combo_1 = append_images(images, direction='horizontal')
combo_2 = append_images(images, direction='horizontal', aligment='top',
                        bg_color=(220, 140, 60))
combo_3 = append_images([combo_1, combo_2], direction='vertical')'combo_3.png')

Example concatenated image

syntaxerror: "unexpected character after line continuation character in python" math

The backslash \ is the line continuation character the error message is talking about, and after it, only newline characters/whitespace are allowed (before the next non-whitespace continues the "interrupted" line.

print "This is a very long string that doesn't fit" + \
      "on a single line"

Outside of a string, a backslash can only appear in this way. For division, you want a slash: /.

If you want to write a verbatim backslash in a string, escape it by doubling it: "\\"

In your code, you're using it twice:

 print("Length between sides: " + str((length*length)*2.6) +
       " \ 1.5 = " +                   # inside a string; treated as literal
       str(((length*length)*2.6)\1.5)+ # outside a string, treated as line cont
                                       # character, but no newline follows -> Fail
       " Units")

What techniques can be used to define a class in JavaScript, and what are their trade-offs?

Following are the ways to create objects in javascript, which I've used so far

Example 1:

obj = new Object(); = 'test';
obj.sayHello = function() {
    console.log('Hello '+;

Example 2:

obj = {}; = 'test';
obj.sayHello = function() {
    console.log('Hello '+;

Example 3:

var obj = function(nameParam) { = nameParam;
obj.prototype.sayHello = function() {
    console.log('Hello '+;

Example 4: Actual benefits of Object.create(). please refer [this link]

var Obj = {
    init: function(nameParam) { = nameParam;
    sayHello: function() {
        console.log('Hello '+;
var usrObj = Object.create(Obj);  // <== one level of inheritance


Example 5 (customised Crockford's Object.create): = function(o) {
   var initArgs =,1)
   function F() {
      if((typeof o.init === 'function') && initArgs.length) {
   F.prototype = o
   return new F()
MY_GLOBAL = {i: 1, nextId: function(){return this.i++}}  // For example

var userB = {
    init: function(nameParam) { = MY_GLOBAL.nextId(); = nameParam;
    sayHello: function() {
        console.log('Hello '+;
var bob =, 'Bob');  // Different from your code

To keep answer updated with ES6/ ES2015

A class is defined like this:

class Person {
    constructor(strName, numAge) { = strName;
        this.age = numAge;

    toString() {
        return '((Class::Person) named ' + + ' & of age ' + this.age + ')';

let objPerson = new Person("Bob",33);

Select folder dialog WPF

I wrote about it on my blog a long time ago, WPF's support for common file dialogs is really bad (or at least is was in 3.5 I didn't check in version 4) - but it's easy to work around it.

You need to add the correct manifest to your application - that will give you a modern style message boxes and folder browser (WinForms FolderBrowserDialog) but not WPF file open/save dialogs, this is described in those 3 posts (if you don't care about the explanation and only want the solution go directly to the 3rd):

Fortunately, the open/save dialogs are very thin wrappers around the Win32 API that is easy to call with the right flags to get the Vista/7 style (after setting the manifest)

What are the complexity guarantees of the standard containers?

I'm not aware of anything like a single table that lets you compare all of them in at one glance (I'm not sure such a table would even be feasible).

Of course the ISO standard document enumerates the complexity requirements in detail, sometimes in various rather readable tables, other times in less readable bullet points for each specific method.

Also the STL library reference at provides the complexity requirements where appropriate.

Navigation Drawer (Google+ vs. YouTube)

There is a great implementation of NavigationDrawer that follows the Google Material Design Guidelines (and compatible down to API 10) - The MaterialDrawer library (link to GitHub). As of time of writing, May 2017, it's actively supported.

It's available in Maven Central repo. Gradle dependency setup:

compile 'com.mikepenz:materialdrawer:5.9.1'

Maven dependency setup:


enter image description here enter image description here

How to solve privileges issues when restore PostgreSQL Database

You can probably safely ignore the error messages in this case. Failing to add a comment to the public schema and installing plpgsql (which should already be installed) aren't going to cause any real problems.

However, if you want to do a complete re-install you'll need a user with appropriate permissions. That shouldn't be the user your application routinely runs as of course.

javascript, is there an isObject function like isArray?

use the following

It will return a true or false

theObject instanceof Object

How do you assert that a certain exception is thrown in JUnit 4 tests?

We can use an assertion fail after the method that must return an exception:

   methodThatThrowMyException();"MyException is not thrown !");
} catch (final Exception exception) {
   // Verify if the thrown exception is instance of MyException, otherwise throws an assert failure
   assertTrue(exception instanceof MyException, "An exception other than MyException is thrown !");
   // In case of verifying the error message
   MyException myException = (MyException) exception;
   assertEquals("EXPECTED ERROR MESSAGE", myException.getMessage());

Stacked Bar Plot in R

A somewhat different approach using ggplot2:

dat <- read.table(text = "A   B   C   D   E   F    G
1 480 780 431 295 670 360  190
2 720 350 377 255 340 615  345
3 460 480 179 560  60 735 1260
4 220 240 876 789 820 100   75", header = TRUE)


dat$row <- seq_len(nrow(dat))
dat2 <- melt(dat, id.vars = "row")


ggplot(dat2, aes(x = variable, y = value, fill = row)) + 
  geom_bar(stat = "identity") +
  xlab("\nType") +
  ylab("Time\n") +
  guides(fill = FALSE) +

this gives:

enter image description here

When you want to include a legend, delete the guides(fill = FALSE) line.

download a file from Spring boot rest service

public ResponseEntity<Resource> downloadFile(@PathVariable(value = "productId") String productId,
        @PathVariable String fileName, HttpServletRequest request) {
    // Load file as Resource
    Resource resource;

    String fileBasePath = "C:\\Users\\v_fzhang\\mobileid\\src\\main\\resources\\data\\Filesdown\\" + productId
            + "\\";
    Path path = Paths.get(fileBasePath + fileName);
    try {
        resource = new UrlResource(path.toUri());
    } catch (MalformedURLException e) {
        return null;

    // Try to determine file's content type
    String contentType = null;
    try {
        contentType = request.getServletContext().getMimeType(resource.getFile().getAbsolutePath());
    } catch (IOException ex) {
        System.out.println("Could not determine file type.");

    // Fallback to the default content type if type could not be determined
    if (contentType == null) {
        contentType = "application/octet-stream";

    return ResponseEntity.ok().contentType(MediaType.parseMediaType(contentType))
            .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + resource.getFilename() + "\"")

To test it, use postman


Vector erase iterator

Something that you can do with modern C++ is using "std::remove_if" and lambda expression;

This code will remove "3" of the vector

vector<int> vec {1,2,3,4,5,6};

vec.erase(std::remove_if(begin(vec),end(vec),[](int elem){return (elem == 3);}), end(vec));

How to send a simple email from a Windows batch file?

If you can't follow Max's suggestion of installing Blat (or any other utility) on your server, then perhaps your server already has software installed that can send emails.

I know that both Oracle and SqlServer have the capability to send email. You might have to work with your DBA to get that feature enabled and/or get the privilege to use it. Of course I can see how that might present its own set of problems and red tape. Assuming you can access the feature, it is fairly simple to have a batch file login to a database and send mail.

A batch file can easily run a VBScript via CSCRIPT. A quick google search finds many links showing how to send email with VBScript. The first one I happened to look at was It looks straight forward.

Python timedelta in years

I'll suggest Pyfdate

What is pyfdate?

Given Python's goal to be a powerful and easy-to-use scripting language, its features for working with dates and times are not as user-friendly as they should be. The purpose of pyfdate is to remedy that situation by providing features for working with dates and times that are as powerful and easy-to-use as the rest of Python.

the tutorial

How can I select all children of an element except the last child?

When IE9 comes, it will be easier. A lot of the time though, you can switch the problem to one requiring :first-child and style the opposite side of the element (IE7+).

How to register ASP.NET 2.0 to web server(IIS7)?

If anyone like me is still unable to register ASP.NET with IIS.

You just need to run these three commands one by one in command prompt

cd c:\windows\Microsoft.Net\Framework\v2.0.50727

after that, Run

aspnet_regiis.exe -i -enable

and Finally Reset IIS


Hope it helps the person in need... cheers!

Change IPython/Jupyter notebook working directory

Usually $ ipython notebook will launch the notebooks and kernels at he current working directory of the terminal.

But if you want to specify the launch directory, you can use --notebook-dir option as follows:

$ ipython notebook --notebook-dir=/path/to/specific/directory

How are parameters sent in an HTTP POST request?

The values are sent in the request body, in the format that the content type specifies.

Usually the content type is application/x-www-form-urlencoded, so the request body uses the same format as the query string:


When you use a file upload in the form, you use the multipart/form-data encoding instead, which has a different format. It's more complicated, but you usually don't need to care what it looks like, so I won't show an example, but it can be good to know that it exists.

How to target the href to div

easy way to do that is like

<a href="demo.html#divid">Demo</a>

Calling C/C++ from Python?

I started my journey in the Python <-> C++ binding from this page, with the objective of linking high level data types (multidimensional STL vectors with Python lists) :-)

Having tried the solutions based on both ctypes and boost.python (and not being a software engineer) I have found them complex when high level datatypes binding is required, while I have found SWIG much more simple for such cases.

This example uses therefore SWIG, and it has been tested in Linux (but SWIG is available and is widely used in Windows too).

The objective is to make a C++ function available to Python that takes a matrix in form of a 2D STL vector and returns an average of each row (as a 1D STL vector).

The code in C++ ("code.cpp") is as follow:

#include <vector>
#include "code.h"

using namespace std;

vector<double> average (vector< vector<double> > i_matrix) {

  // Compute average of each row..
  vector <double> averages;
  for (int r = 0; r < i_matrix.size(); r++){
    double rsum = 0.0;
    double ncols= i_matrix[r].size();
    for (int c = 0; c< i_matrix[r].size(); c++){
      rsum += i_matrix[r][c];
  return averages;

The equivalent header ("code.h") is:

#ifndef _code
#define _code

#include <vector>

std::vector<double> average (std::vector< std::vector<double> > i_matrix);


We first compile the C++ code to create an object file:

g++ -c -fPIC code.cpp

We then define a SWIG interface definition file ("code.i") for our C++ functions.

%module code
#include "code.h"
%include "std_vector.i"
namespace std {

  /* On a side note, the names VecDouble and VecVecdouble can be changed, but the order of first the inner vector matters! */
  %template(VecDouble) vector<double>;
  %template(VecVecdouble) vector< vector<double> >;

%include "code.h"

Using SWIG, we generate a C++ interface source code from the SWIG interface definition file..

swig -c++ -python code.i

We finally compile the generated C++ interface source file and link everything together to generate a shared library that is directly importable by Python (the "_" matters):

g++ -c -fPIC code_wrap.cxx  -I/usr/include/python2.7 -I/usr/lib/python2.7
g++ -shared -Wl,-soname, -o code.o code_wrap.o

We can now use the function in Python scripts:

#!/usr/bin/env python

import code
a= [[3,5,7],[8,10,12]]
print a
b = code.average(a)
print "Assignment done"
print a
print b

Convert Unix timestamp to a date string

Other examples here are difficult to remember. At its simplest:

date -r 1305712800

Display a loading bar before the entire page is loaded


<div class="preload">
<img src="">

<div class="content">
I would like to display a loading bar before the entire page is loaded. 


$(function() {
    $(".preload").fadeOut(2000, function() {


.content {display:none;}
.preload { 
    height: 100px;
    position: fixed;
    top: 50%;
    left: 50%;


How to execute an .SQL script file using c#

I tried this solution with Microsoft.SqlServer.Management but it didn't work well with .NET 4.0 so I wrote another solution using .NET libs framework only.

string script = File.ReadAllText(@"E:\someSqlScript.sql");

// split script on GO command
IEnumerable<string> commandStrings = Regex.Split(script, @"^\s*GO\s*$", RegexOptions.Multiline | RegexOptions.IgnoreCase);

foreach (string commandString in commandStrings)
    if (!string.IsNullOrWhiteSpace(commandString.Trim()))
        using(var command = new SqlCommand(commandString, Connection))

Masking password input from the console : Java

You would use the Console class

char[] password = console.readPassword("Enter password");  
Arrays.fill(password, ' ');

By executing readPassword echoing is disabled. Also after the password is validated it is best to overwrite any values in the array.

If you run this from an ide it will fail, please see this explanation for a thorough answer: Explained

The origin server did not find a current representation for the target resource or is not willing to disclose that one exists. on deploying to tomcat

Trying to run a servlet in Eclipse (right-click + "Run on Server") I encountered the very same problem: "HTTP Status: 404 / Description: The origin server did not find a current representation for the target resource or is not willing to disclose that one exists." Adding an index.html did not help, neither changing various settings of the tomcat.

Finally, I found the problem in an unexpected place: In Eclipse, the Option "Build automatically" was not set. Thus the servlet was not compiled, and no File "myServlet.class" was deployed to the server (in my case in the path .wtpwebapps/projectXX/WEB-INF/classes/XXpackage/). Building the project manually and restarting the server solved the problem.

My environment: Eclipse Neon.3 Release 4.6.3, Tomcat-Version 8.5.14., OS Linux Mint 18.1.

How can I tell jaxb / Maven to generate multiple schema packages?

You can use also JAXB bindings to specify different package for each schema, e.g.

<jaxb:bindings xmlns:jaxb="" xmlns:xjc=""
    xmlns:xs="" version="2.0" schemaLocation="book.xsd">

        <xjc:serializable uid="1" />

        <jaxb:package name="" />


Then just use the new maven-jaxb2-plugin 0.8.0 <schemas> and <bindings> elements in the pom.xml. Or specify the top most directory in <schemaDirectory> and <bindingDirectory> and by <include> your schemas and bindings:


I think this is more convenient solution, because when you add a new XSD you do not need to change Maven pom.xml, just add a new XJB binding file to the same directory.

BOOLEAN or TINYINT confusion

MySQL does not have internal boolean data type. It uses the smallest integer data type - TINYINT.

The BOOLEAN and BOOL are equivalents of TINYINT(1), because they are synonyms.

Try to create this table -


Then run SHOW CREATE TABLE, you will get this output -

CREATE TABLE `table1` (
  `column1` tinyint(1) DEFAULT NULL

Add class to an element in Angular 4

If you need that each div will have its own toggle and don't want clicks to affect other divs, do this:

Here's what I did to solve this...

<div [ngClass]="{'teaser': !teaser_1 }" (click)="teaser_1=!teaser_1">

<div [ngClass]="{'teaser': !teaser_2 }" (click)="teaser_2=!teaser_2">

<div [ngClass]="{'teaser': !teaser_3 }" (click)="teaser_3=!teaser_3">

it requires custom numbering which sucks, but it works.

Google maps API V3 method fitBounds()

This happens because LatLngBounds() does not take two arbitrary points as parameters, but SW and NE points

use the .extend() method on an empty bounds object

var bounds = new google.maps.LatLngBounds();

Demo at

How to loop through a checkboxlist and to find what's checked and not checked?

for (int i = 0; i < clbIncludes.Items.Count; i++)
  if (clbIncludes.GetItemChecked(i))
    // Do selected stuff
    // Do unselected stuff

If the the check is in indeterminate state, this will still return true. You may want to replace

if (clbIncludes.GetItemChecked(i))


if (clbIncludes.GetItemCheckState(i) == CheckState.Checked)

if you want to only include actually checked items.

How can I use break or continue within for loop in Twig template?

From docs TWIG docs:

Unlike in PHP, it's not possible to break or continue in a loop.

But still:

You can however filter the sequence during iteration which allows you to skip items.

Example 1 (for huge lists you can filter posts using slice, slice(start, length)):

{% for post in posts|slice(0,10) %}
    <h2>{{ post.heading }}</h2>
{% endfor %}

Example 2:

{% for post in posts if < 10 %}
    <h2>{{ post.heading }}</h2>
{% endfor %}

You can even use own TWIG filters for more complexed conditions, like:

{% for post in posts|onlySuperPosts %}
    <h2>{{ post.heading }}</h2>
{% endfor %}

Best data type for storing currency values in a MySQL database

You could use something like DECIMAL(19,2) by default for all of your monetary values, but if you'll only ever store values lower than $1,000, that's just going to be a waste of valuable database space.

For most implementations, DECIMAL(N,2) would be sufficient, where the value of N is at least the number of digits before the . of the greatest sum you ever expect to be stored in that field + 5. So if you don't ever expect to store any values greater than 999999.99, DECIMAL(11,2) should be more than sufficient (until expectations change).

If you want to be GAAP compliant, you could go with DECIMAL(N,4), where the value of N is at least the number of digits before the . of the greatest sum you ever expect to be stored in that field + 7.

How to loop through all elements of a form jQuery

From the jQuery :input selector page:

Because :input is a jQuery extension and not part of the CSS specification, queries using :input cannot take advantage of the performance boost provided by the native DOM querySelectorAll() method. To achieve the best performance when using :input to select elements, first select the elements using a pure CSS selector, then use .filter(":input").

This is the best choice.

$('#new_user_form *').filter(':input').each(function(){
    //your code here

Google Maps API OVER QUERY LIMIT per second limit

Instead of client-side geocoding

    'address': your_address
  }, function (results, status) {
     if (status == google.maps.GeocoderStatus.OK) {
       var geo_data = results[0];
       // your code ...

I would go to server-side geocoding API

var apikey = YOUR_API_KEY;
var query = '' + address + '&key=' + apikey;
$.getJSON(query, function (data) {
  if (data.status === 'OK') { 
    var geo_data = data.results[0];

How do I stop/start a scheduled task on a remote computer programmatically?

schtasks /change /disable /tn "Name Of Task" /s REMOTEMACHINENAME /u mydomain\administrator /p adminpassword 

List all the files and folders in a Directory with PHP recursive function

To whom needs list files first than folders (with alphabetical older).

Can use following function. This is not self calling function. So you will have directory list, directory view, files list and folders list as seperated array also.

I spend two days for this and do not want someone will wast his time for this also, hope helps someone.

function dirlist($dir){
    if(!file_exists($dir)){ return $dir.' does not exists'; }
    $list = array('path' => $dir, 'dirview' => array(), 'dirlist' => array(), 'files' => array(), 'folders' => array());

    $dirs = array($dir);
    while(null !== ($dir = array_pop($dirs))){
        if($dh = opendir($dir)){
            while(false !== ($file = readdir($dh))){
                if($file == '.' || $file == '..') continue;
                $path = $dir.DIRECTORY_SEPARATOR.$file;
                $list['dirlist_natural'][] = $path;
                    $list['dirview'][$dir]['folders'][] = $path;
                    // Bos klasorler while icerisine tekrar girmeyecektir. Klasorun oldugundan emin olalim.
                    if(!isset($list['dirview'][$path])){ $list['dirview'][$path] = array(); }
                    $dirs[] = $path;
                    //if($path == 'D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-content\upgrade'){ press($path); press($list['dirview']); die; }
                    $list['dirview'][$dir]['files'][] = $path;

    // if(!empty($dirlist['dirlist_natural']))  sort($dirlist['dirlist_natural'], SORT_LOCALE_STRING); // delete safe ama gerek kalmadi.

    if(!empty($list['dirview'])) ksort($list['dirview']);

    // Dosyalari dogru siralama yaptiriyoruz. Deniz P. - info[at]
    foreach($list['dirview'] as $path => $file){
            $list['dirlist'][] = $path;
            $list['files'] = array_merge($list['files'], $file['files']);
            $list['dirlist'] = array_merge($list['dirlist'], $file['files']);
        // Add empty folders to the list
        if(is_dir($path) && array_search($path, $list['dirlist']) === false){
            $list['dirlist'][] = $path;
            $list['folders'] = array_merge($list['folders'], $file['folders']);

    //press(array_diff($list['dirlist_natural'], $list['dirlist'])); press($list['dirview']); die;

    return $list;

will output something like this.

[D:\Xampp\htdocs\exclusiveyachtcharter.localhost] => Array
                    [files] => Array
                            [0] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\.htaccess
                            [1] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\index.php
                            [2] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\license.txt
                            [3] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\php.php
                            [4] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\readme.html
                            [5] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-activate.php
                            [6] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-blog-header.php
                            [7] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-comments-post.php
                            [8] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-config-sample.php
                            [9] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-config.php
                            [10] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-cron.php
                            [11] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-links-opml.php
                            [12] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-load.php
                            [13] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-login.php
                            [14] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-mail.php
                            [15] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-settings.php
                            [16] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-signup.php
                            [17] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-trackback.php
                            [18] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\xmlrpc.php

                    [folders] => Array
                            [0] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\exclusiv_excluwlsql
                            [1] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-admin
                            [2] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-content
                            [3] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-includes


dirview output

    [dirview] => Array
            [0] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\.htaccess
            [1] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\index.php
            [2] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\license.txt
            [3] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\php.php
            [4] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\readme.html
            [5] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-activate.php
            [6] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-blog-header.php
            [7] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-comments-post.php
            [8] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-config-sample.php
            [9] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-config.php
            [10] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-cron.php
            [11] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-links-opml.php
            [12] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-load.php
            [13] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-login.php
            [14] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-mail.php
            [15] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-settings.php
            [16] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-signup.php
            [17] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\wp-trackback.php
            [18] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\xmlrpc.php
            [19] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost
            [20] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\exclusiv_excluwlsql\exclusiv_excluwl.sql
            [21] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\exclusiv_excluwlsql\
            [22] => D:\Xampp\htdocs\exclusiveyachtcharter.localhost\exclusiv_excluwlsql

How do I push a local repo to Bitbucket using SourceTree without creating a repo on bitbucket first?

Bitbucket supports a REST API you can use to programmatically create Bitbucket repositories.

Documentation and cURL sample available here:

$ curl -X POST -v -u username:password -H "Content-Type: application/json" \ \
   -d '{"scm": "git", "is_private": "true", "fork_policy": "no_public_forks" }'

Under Windows, curl is available from the Git Bash shell.

Using this method you could easily create a script to import many repos from a local git server to Bitbucket.

Parse large JSON file in Nodejs

I wrote a module that can do this, called BFJ. Specifically, the method bfj.match can be used to break up a large stream into discrete chunks of JSON:

const bfj = require('bfj');
const fs = require('fs');

const stream = fs.createReadStream(filePath);

bfj.match(stream, (key, value, depth) => depth === 0, { ndjson: true })
  .on('data', object => {
    // do whatever you need to do with object
  .on('dataError', error => {
    // a syntax error was found in the JSON
  .on('error', error => {
    // some kind of operational error occurred
  .on('end', error => {
    // finished processing the stream

Here, bfj.match returns a readable, object-mode stream that will receive the parsed data items, and is passed 3 arguments:

  1. A readable stream containing the input JSON.

  2. A predicate that indicates which items from the parsed JSON will be pushed to the result stream.

  3. An options object indicating that the input is newline-delimited JSON (this is to process format B from the question, it's not required for format A).

Upon being called, bfj.match will parse JSON from the input stream depth-first, calling the predicate with each value to determine whether or not to push that item to the result stream. The predicate is passed three arguments:

  1. The property key or array index (this will be undefined for top-level items).

  2. The value itself.

  3. The depth of the item in the JSON structure (zero for top-level items).

Of course a more complex predicate can also be used as necessary according to requirements. You can also pass a string or a regular expression instead of a predicate function, if you want to perform simple matches against property keys.

How to fix the Hibernate "object references an unsaved transient instance - save the transient instance before flushing" error

Case 1: I was getting this exception when I was trying to create a parent and saving that parent reference to its child and then some other DELETE/UPDATE query(JPQL). So I just flush() the newly created entity after creating parent and after creating child using same parent reference. It Worked for me.

Case 2:

Parent class

public class Reference implements Serializable {

    @Column(precision=20, scale=0)
    private BigInteger id;

    private Date modifiedOn;

    private ReferenceAdditionalDetails refAddDetails;

Child Class:

public class ReferenceAdditionalDetails implements Serializable{

    private static final long serialVersionUID = 1L;

    private Reference reference;

    private String preferedSector1;
    private String preferedSector2;


In the above case where parent(Reference) and child(ReferenceAdditionalDetails) having OneToOne relationship and when you try to create Reference entity and then its child(ReferenceAdditionalDetails), it will give you the same exception. So to avoid the exception you have to set null for child class and then create the parent.(Sample Code)

reference = referenceDao.create(reference);

Reversing an Array in Java

you messed up

int[] firstArray = new int[]{1,2,3,4};
int[] reversedArray = new int[firstArray.length];
int j = 0;
for (int i = firstArray.length -1; i >= 0; i--){
    reversedArray[j++] = firstArray[i];

Entity Framework - Include Multiple Levels of Properties

I also had to use multiple includes and at 3rd level I needed multiple properties

(from e in context.JobCategorySet
                      where e.Id == id &&
                            e.AgencyId == agencyId
                      select e)
                      .Include(x => x.JobCategorySkillDetails)
                      .Include(x => x.Shifts.Select(r => r.Rate).Select(rt => rt.DurationType))
                      .Include(x => x.Shifts.Select(r => r.Rate).Select(rt => rt.RuleType))
                      .Include(x => x.Shifts.Select(r => r.Rate).Select(rt => rt.RateType))

This may help someone :)

In Perl, how can I concisely check if a $variable is defined and contains a non zero length string?

In cases where I don't care whether the variable is undef or equal to '', I usually summarize it as:

$name = "" unless defined $name;
if($name ne '') {
  # do something with $name

Where are Docker images stored on the host machine?

Expanding on Tristan's answer, in Windows with Hyper-V you can move the image with these steps from matthuisman:

In Windows 10,

  1. Stop docker etc
  2. Type "Hyper-V Manager" in task-bar search box and run it.
  3. Select your PC in the left hand pane (Mine is called DESKTOP-CBP**)
  4. Right click on the correct virtual machine (Mine is called MobyLinuxVM)
  5. Select "Turn off" (If it is running)
  6. Right click on it again and select "Move"
  7. Follow the prompts

How to fix syntax error, unexpected T_IF error in php?

add semi-colon the line before:

$total_pages = ceil($total_result / $per_page);

ASP.NET Core configuration for .NET Core console application

I was mistaken. You can use the new ConfigurationBuilder from a netcore console application.

See for an example.

However, only aspnet core has dependency injection out of the box so you don't have the ability to have strongly typed configuration settings and automatically inject them using IOptions.

How to git ignore subfolders / subdirectories?

To exclude content and subdirectories:


To just exclude all subdirectories but take the content, add "/":


Detecting when Iframe content has loaded (Cross browser)

See this blog post. It uses jQuery, but it should help you even if you are not using it.

Basically you add this to your document.ready()

$('iframe').load(function() {

C++ - How to append a char to char*?

Remove those char * ret declarations inside if blocks which hide outer ret. Therefor you have memory leak and on the other hand un-allocated memory for ret.

To compare a c-style string you should use strcmp(array,"") not array!="". Your final code should looks like below:

char* appendCharToCharArray(char* array, char a)
    size_t len = strlen(array);

    char* ret = new char[len+2];

    strcpy(ret, array);    
    ret[len] = a;
    ret[len+1] = '\0';

    return ret;

Note that, you must handle the allocated memory of returned ret somewhere by delete[] it.


Why you don't use std::string? it has .append method to append a character at the end of a string:

std::string str;

// or
str += x;

Writing to a file in a for loop

It's preferable to use context managers to close the files automatically

with open("new.txt", "r"), open('xyz.txt', 'w') as textfile, myfile:
    for line in textfile:
        var1, var2 = line.split(",");

How do I make a simple crawler in PHP?

Here my implementation based on the above example/answer.

  1. It is class based
  2. uses Curl
  3. support HTTP Auth
  4. Skip Url not belonging to the base domain
  5. Return Http header Response Code for each page
  6. Return time for each page


class crawler
    protected $_url;
    protected $_depth;
    protected $_host;
    protected $_useHttpAuth = false;
    protected $_user;
    protected $_pass;
    protected $_seen = array();
    protected $_filter = array();

    public function __construct($url, $depth = 5)
        $this->_url = $url;
        $this->_depth = $depth;
        $parse = parse_url($url);
        $this->_host = $parse['host'];

    protected function _processAnchors($content, $url, $depth)
        $dom = new DOMDocument('1.0');
        $anchors = $dom->getElementsByTagName('a');

        foreach ($anchors as $element) {
            $href = $element->getAttribute('href');
            if (0 !== strpos($href, 'http')) {
                $path = '/' . ltrim($href, '/');
                if (extension_loaded('http')) {
                    $href = http_build_url($url, array('path' => $path));
                } else {
                    $parts = parse_url($url);
                    $href = $parts['scheme'] . '://';
                    if (isset($parts['user']) && isset($parts['pass'])) {
                        $href .= $parts['user'] . ':' . $parts['pass'] . '@';
                    $href .= $parts['host'];
                    if (isset($parts['port'])) {
                        $href .= ':' . $parts['port'];
                    $href .= $path;
            // Crawl only link that belongs to the start domain
            $this->crawl_page($href, $depth - 1);

    protected function _getContent($url)
        $handle = curl_init($url);
        if ($this->_useHttpAuth) {
            curl_setopt($handle, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
            curl_setopt($handle, CURLOPT_USERPWD, $this->_user . ":" . $this->_pass);
        // follows 302 redirect, creates problem wiht authentication
//        curl_setopt($handle, CURLOPT_FOLLOWLOCATION, TRUE);
        // return the content
        curl_setopt($handle, CURLOPT_RETURNTRANSFER, TRUE);

        /* Get the HTML or whatever is linked in $url. */
        $response = curl_exec($handle);
        // response total time
        $time = curl_getinfo($handle, CURLINFO_TOTAL_TIME);
        /* Check for 404 (file not found). */
        $httpCode = curl_getinfo($handle, CURLINFO_HTTP_CODE);

        return array($response, $httpCode, $time);

    protected function _printResult($url, $depth, $httpcode, $time)
        $currentDepth = $this->_depth - $depth;
        $count = count($this->_seen);
        echo "N::$count,CODE::$httpcode,TIME::$time,DEPTH::$currentDepth URL::$url <br>";

    protected function isValid($url, $depth)
        if (strpos($url, $this->_host) === false
            || $depth === 0
            || isset($this->_seen[$url])
        ) {
            return false;
        foreach ($this->_filter as $excludePath) {
            if (strpos($url, $excludePath) !== false) {
                return false;
        return true;

    public function crawl_page($url, $depth)
        if (!$this->isValid($url, $depth)) {
        // add to the seen URL
        $this->_seen[$url] = true;
        // get Content and Return Code
        list($content, $httpcode, $time) = $this->_getContent($url);
        // print Result for current Page
        $this->_printResult($url, $depth, $httpcode, $time);
        // process subPages
        $this->_processAnchors($content, $url, $depth);

    public function setHttpAuth($user, $pass)
        $this->_useHttpAuth = true;
        $this->_user = $user;
        $this->_pass = $pass;

    public function addFilterPath($path)
        $this->_filter[] = $path;

    public function run()
        $this->crawl_page($this->_url, $this->_depth);


$startURL = 'http://YOUR_URL/';
$depth = 6;
$username = 'YOURUSER';
$password = 'YOURPASS';
$crawler = new crawler($startURL, $depth);
$crawler->setHttpAuth($username, $password);
// Exclude path with the following structure to be processed 

Spring not autowiring in unit tests with JUnit

You need to use the Spring JUnit runner in order to wire in Spring beans from your context. The code below assumes that you have a application context called testContest.xml available on the test classpath.

import org.hibernate.SessionFactory;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.transaction.annotation.Transactional;

import java.sql.SQLException;

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.startsWith;

@ContextConfiguration(locations = {"classpath*:**/testContext.xml"})
public class someDaoTest {

    protected SessionFactory sessionFactory;

    public void testDBSourceIsCorrect() throws SQLException {
        String databaseProductName = sessionFactory.getCurrentSession()
        assertThat("Test container is pointing at the wrong DB.", databaseProductName, startsWith("HSQL"));

Note: This works with Spring 2.5.2 and Hibernate 3.6.5

EF LINQ include multiple and nested entities

In Entity Framework Core (EF.core) you can use .ThenInclude for including next levels.

var blogs = context.Blogs
    .Include(blog => blog.Posts)
        .ThenInclude(post => post.Author)

More information:

Note: Say you need multiple ThenInclude() on blog.Posts, just repeat the Include(blog => blog.Posts) and do another ThenInclude(post => post.Other).

var blogs = context.Blogs
    .Include(blog => blog.Posts)
        .ThenInclude(post => post.Author)
    .Include(blog => blog.Posts)
        .ThenInclude(post => post.Other)

How do I represent a time only value in .NET?

In addition to Chibueze Opata:

class Time
    public int Hours   { get; private set; }
    public int Minutes { get; private set; }
    public int Seconds { get; private set; }

    public Time(uint h, uint m, uint s)
        if(h > 23 || m > 59 || s > 59)
            throw new ArgumentException("Invalid time specified");
        Hours = (int)h; Minutes = (int)m; Seconds = (int)s;

    public Time(DateTime dt)
        Hours = dt.Hour;
        Minutes = dt.Minute;
        Seconds = dt.Second;

    public override string ToString()
        return String.Format(
            this.Hours, this.Minutes, this.Seconds);

    public void AddHours(uint h)
        this.Hours += (int)h;

    public void AddMinutes(uint m)
        this.Minutes += (int)m;
        while(this.Minutes > 59)
            this.Minutes -= 60;

    public void AddSeconds(uint s)
        this.Seconds += (int)s;
        while(this.Seconds > 59)
            this.Seconds -= 60;

Print current call stack from a method in Python code

import traceback

get keys of json-object in JavaScript

The working code

var jsonData = [{person:"me", age :"30"},{person:"you",age:"25"}];_x000D_
for(var obj in jsonData){_x000D_
    for(var prop in jsonData[obj]){_x000D_
           alert(prop + ':' + jsonData[obj][prop]);_x000D_

Javascript: Easier way to format numbers?

No, there is no built-in support for number formatting, but googling will turn up loads of code snippets that will do this for you.

EDIT: I missed the last sentence of your post. Try for a jQuery solution.

Best way to remove from NSMutableArray while iterating?

Here's the easy and clean way. I like to duplicate my array right in the fast enumeration call:

for (LineItem *item in [NSArray arrayWithArray:self.lineItems]) 
    if ([item.toBeRemoved boolValue] == YES) 
        [self.lineItems removeObject:item];

This way you enumerate through a copy of the array being deleted from, both holding the same objects. An NSArray holds object pointers only so this is totally fine memory/performance wise.

RecyclerView - How to smooth scroll to top of item on a certain position?

i Used Like This :

recyclerView.getLayoutManager().smoothScrollToPosition(recyclerView, new RecyclerView.State(), 5);

How to use jQuery to get the current value of a file input field

I think it should be


How to get a matplotlib Axes instance to plot to?

You can either

fig, ax = plt.subplots()  #create figure and axes
candlestick(ax, quotes, ...)


candlestick(plt.gca(), quotes) #get the axis when calling the function

The first gives you more flexibility. The second is much easier if candlestick is the only thing you want to plot

How to read multiple Integer values from a single line of input in Java?

When we want to take Integer as inputs
For just 3 inputs as in your case:

import java.util.Scanner;
Scanner scan = new Scanner(;
int a,b,c;
a = scan.nextInt();
b = scan.nextInt();
c = scan.nextInt();

For more number of inputs we can use a loop:

import java.util.Scanner;
Scanner scan = new Scanner(;
int a[] = new int[n]; //where n is the number of inputs
for(int i=0;i<n;i++){
    a[i] = scan.nextInt();    

Forward host port to docker container

I had a similar problem accessing a LDAP-Server from a docker container. I set a fixed IP for the container and added a firewall rule.


version: '2'
    image: dockerImageName:latest
      - "dockerhost:"
      - subnet:

iptables rule:

iptables -A INPUT -j ACCEPT -p tcp -s -d $ --dport portnumberOnHost

Inside the container access dockerhost:portnumberOnHost

check if file exists in php

You can also use PHP get_headers() function.


function check_file_exists_here($url){
   return stripos($result[0],"200 OK")?true:false; //check if $result[0] has 200 OK

   echo "This file exists";
   echo "This file does not exist";

How to set editable true/false EditText in Android programmatically?

hope this one helps you out:


How to determine day of week by passing specific date?

import java.text.SimpleDateFormat;
import java.util.Scanner;

class DayFromDate {

    public static void main(String args[]) {

        System.out.println("Enter the date(dd/mm/yyyy):");
        Scanner scan = new Scanner(;
        String Date = scan.nextLine();

        try {
            boolean dateValid = dateValidate(Date);

            if(dateValid == true) {
                SimpleDateFormat df = new SimpleDateFormat( "dd/MM/yy" );  
                java.util.Date date = df.parse( Date );   
                df.applyPattern( "EEE" );  
                String day= df.format( date ); 

                if(day.compareTo("Sat") == 0 || day.compareTo("Sun") == 0) {
                    System.out.println(day + ": Weekend");
                } else {
                    System.out.println(day + ": Weekday");
            } else {
                System.out.println("Invalid Date!!!");
        } catch(Exception e) {
            System.out.println("Invalid Date Formats!!!");

    static public boolean dateValidate(String d) {

        String dateArray[] = d.split("/");
        int day = Integer.parseInt(dateArray[0]);
        int month = Integer.parseInt(dateArray[1]);
        int year = Integer.parseInt(dateArray[2]);
        System.out.print(day + "\n" + month + "\n" + year + "\n");
        boolean leapYear = false;

        if((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0)) {
            leapYear = true;

        if(year > 2099 || year < 1900)
            return false;

        if(month < 13) {
            if(month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12) {
                if(day > 31)
                    return false;
            } else if(month == 4 || month == 6 || month == 9 || month == 11) {
                if(day > 30)
                    return false;
            } else if(leapYear == true && month == 2) {
                if(day > 29)
                    return false;
            } else if(leapYear == false && month == 2) {
                if(day > 28)
                    return false;

            return true;    
        } else return false;

Centering brand logo in Bootstrap Navbar

Old question, but just for posterity.

I've found the easiest way to do it is to have the image as the background image of the navbar-brand. Just makes sure to put in a custom width.

    margin-left: auto;
    margin-right: auto;
    width: 150px;
    background-image: url('logo.png');

How to enable or disable an anchor using jQuery?

Try the below lines

$("#yourbuttonid").attr("disabled", "disabled");

Coz, Even if you disable <a> tag href will work so you must remove href also.

When you want enable try below lines

$("#yourbuttonid").attr("href", "#nav-panel");

What's the best way to validate an XML file against an XSD file?

Validate against online schemas

Source xmlFile = new StreamSource(Thread.currentThread().getContextClassLoader().getResourceAsStream("your.xml"));
SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
Schema schema = factory.newSchema(Thread.currentThread().getContextClassLoader().getResource("your.xsd"));
Validator validator = schema.newValidator();

Validate against local schemas

Offline XML Validation with Java

Why can't I use background image and color together?

Here's an example of using background-image and background-color together:

.box {_x000D_
  background-image: repeating-linear-gradient( -45deg, rgba(255, 255, 255, .2), rgba(255, 255, 255, .2) 15px, transparent 15px, transparent 30px);_x000D_
  width: 100px;_x000D_
  height: 100px;_x000D_
  margin: 10px 0 0 10px;_x000D_
  display: inline-block;_x000D_
<div class="box" style="background-color:orange"></div>_x000D_
<div class="box" style="background-color:green"></div>_x000D_
<div class="box" style="background-color:blue"></div>

SaveFileDialog setting default path and file type?

The SaveFileDialog control won't do any saving at all. All it does is providing you a convenient interface to actually display Windows' default file save dialog.

  1. Set the property InitialDirectory to the drive you'd like it to show some other default. Just think of other computers that might have a different layout. By default windows will save the directory used the last time and present it again.

  2. That is handled outside the control. You'll have to check the dialog's results and then do the saving yourself (e.g. write a text or binary file).

Just as a quick example (there are alternative ways to do it). savefile is a control of type SaveFileDialog

SaveFileDialog savefile = new SaveFileDialog(); 
// set a default file name
savefile.FileName = "unknown.txt";
// set filters - this can be done in properties as well
savefile.Filter = "Text files (*.txt)|*.txt|All files (*.*)|*.*";

if (savefile.ShowDialog() == DialogResult.OK)
    using (StreamWriter sw = new StreamWriter(savefile.FileName))
        sw.WriteLine ("Hello World!");

Failed to Connect to MySQL at localhost:3306 with user root

Open System Preference > MySQL > Initialize Database > Use Legacy Password Encription

How to start automatic download of a file in Internet Explorer?

I had a similar issue and none of the above solutions worked for me. Here's my try (requires jquery):

$(function() {
    var $this = $(this);
    setTimeout(function() {
      window.location = $this.attr('href');
    }, 2000);

Usage: Just add an attribute called data-auto-download to the link pointing to the download in question:

<p>The download should start shortly. If it doesn't, click
<a data-auto-download href="/your/file/url">here</a>.</p>

It should work in all cases.

How to deal with "java.lang.OutOfMemoryError: Java heap space" error?

If you need to monitor your memory usage at runtime, the package offers MBeans that can be used to monitor the memory pools in your VM (eg, eden space, tenured generation etc), and also garbage collection behaviour.

The free heap space reported by these MBeans will vary greatly depending on GC behaviour, particularly if your application generates a lot of objects which are later GC-ed. One possible approach is to monitor the free heap space after each full-GC, which you may be able to use to make a decision on freeing up memory by persisting objects.

Ultimately, your best bet is to limit your memory retention as far as possible whilst performance remains acceptable. As a previous comment noted, memory is always limited, but your app should have a strategy for dealing with memory exhaustion.

catching stdout in realtime from subprocess

Change the stdout from the rsync process to be unbuffered.

p = subprocess.Popen(cmd,
                     bufsize=0,  # 0=unbuffered, 1=line-buffered, else buffer-size

Comparing Dates in Oracle SQL

31-DEC-95 isn't a string, nor is 20-JUN-94. They're numbers with some extra stuff added on the end. This should be '31-DEC-95' or '20-JUN-94' - note the single quote, '. This will enable you to do a string comparison.

However, you're not doing a string comparison; you're doing a date comparison. You should transform your string into a date. Either by using the built-in TO_DATE() function, or a date literal.


select employee_id
  from employee
 where employee_date_hired > to_date('31-DEC-95','DD-MON-YY')

This method has a few unnecessary pitfalls

  • As a_horse_with_no_name noted in the comments, DEC, doesn't necessarily mean December. It depends on your NLS_DATE_LANGUAGE and NLS_DATE_FORMAT settings. To ensure that your comparison with work in any locale you can use the datetime format model MM instead
  • The year '95 is inexact. You know you mean 1995, but what if it was '50, is that 1950 or 2050? It's always best to be explicit
select employee_id
  from employee
 where employee_date_hired > to_date('31-12-1995','DD-MM-YYYY')

Date literals

A date literal is part of the ANSI standard, which means you don't have to use an Oracle specific function. When using a literal you must specify your date in the format YYYY-MM-DD and you cannot include a time element.

select employee_id
  from employee
 where employee_date_hired > date '1995-12-31'

Remember that the Oracle date datatype includes a time elemement, so the date without a time portion is equivalent to 1995-12-31 00:00:00.

If you want to include a time portion then you'd have to use a timestamp literal, which takes the format YYYY-MM-DD HH24:MI:SS[.FF0-9]

select employee_id
  from employee
 where employee_date_hired > timestamp '1995-12-31 12:31:02'

Further information

NLS_DATE_LANGUAGE is derived from NLS_LANGUAGE and NLS_DATE_FORMAT is derived from NLS_TERRITORY. These are set when you initially created the database but they can be altered by changing your inialization parameters file - only if really required - or at the session level by using the ALTER SESSION syntax. For instance:

alter session set nls_date_format = 'DD.MM.YYYY HH24:MI:SS';

This means:

  • DD numeric day of the month, 1 - 31
  • MM numeric month of the year, 01 - 12 ( January is 01 )
  • YYYY 4 digit year - in my opinion this is always better than a 2 digit year YY as there is no confusion with what century you're referring to.
  • HH24 hour of the day, 0 - 23
  • MI minute of the hour, 0 - 59
  • SS second of the minute, 0-59

You can find out your current language and date language settings by querying V$NLS_PARAMETERSs and the full gamut of valid values by querying V$NLS_VALID_VALUES.

Further reading

Incidentally, if you want the count(*) you need to group by employee_id

select employee_id, count(*)
  from employee
 where employee_date_hired > date '1995-12-31'
 group by employee_id

This gives you the count per employee_id.

Print out the values of a (Mat) matrix in OpenCV C++

If you are using opencv3, you can print Mat like python numpy style:

Mat xTrainData = (Mat_<float>(5,2) << 1, 1, 1, 1, 2, 2, 2, 2, 2, 2);

cout << "xTrainData (python)  = " << endl << format(xTrainData, Formatter::FMT_PYTHON) << endl << endl;

Output as below, you can see it'e more readable, see here for more information.

enter image description here

But in most case, there is no need to output all the data in Mat, you can output by row range like 0 ~ 2 row:

#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>

#include <iostream>
#include <iomanip>

using namespace cv;
using namespace std;

int main(int argc, char** argv)
    //row: 6, column: 3,unsigned one channel
    Mat image1(6, 3, CV_8UC1, 5);

    // output row: 0 ~ 2
    cout << "image1 row: 0~2 = "<< endl << " "  << image1.rowRange(0, 2) << endl << endl;

    //row: 8, column: 2,unsigned three channel
    Mat image2(8, 2, CV_8UC3, Scalar(1, 2, 3));

    // output row: 0 ~ 2
    cout << "image2 row: 0~2 = "<< endl << " "  << image2.rowRange(0, 2) << endl << endl;

    return 0;

Output as below:

enter image description here

How to assign a NULL value to a pointer in python?

left = None

left is None #evaluates to True

overlay a smaller image on a larger image python OpenCv

A simple function that blits an image front onto an image back and returns the result. It works with both 3 and 4-channel images and deals with the alpha channel. Overlaps are handled as well.

The output image has the same size as back, but always 4 channels.
The output alpha channel is given by (u+v)/(1+uv) where u,v are the alpha channels of the front and back image and -1 <= u,v <= 1. Where there is no overlap with front, the alpha value from back is taken.

import cv2

def merge_image(back, front, x,y):
    # convert to rgba
    if back.shape[2] == 3:
        back = cv2.cvtColor(back, cv2.COLOR_BGR2BGRA)
    if front.shape[2] == 3:
        front = cv2.cvtColor(front, cv2.COLOR_BGR2BGRA)

    # crop the overlay from both images
    bh,bw = back.shape[:2]
    fh,fw = front.shape[:2]
    x1, x2 = max(x, 0), min(x+fw, bw)
    y1, y2 = max(y, 0), min(y+fh, bh)
    front_cropped = front[y1-y:y2-y, x1-x:x2-x]
    back_cropped = back[y1:y2, x1:x2]

    alpha_front = front_cropped[:,:,3:4] / 255
    alpha_back = back_cropped[:,:,3:4] / 255
    # replace an area in result with overlay
    result = back.copy()
    print(f'af: {alpha_front.shape}\nab: {alpha_back.shape}\nfront_cropped: {front_cropped.shape}\nback_cropped: {back_cropped.shape}')
    result[y1:y2, x1:x2, :3] = alpha_front * front_cropped[:,:,:3] + alpha_back * back_cropped[:,:,:3]
    result[y1:y2, x1:x2, 3:4] = (alpha_front + alpha_back) / (1 + alpha_front*alpha_back) * 255

    return result

Pointer to 2D arrays in C

Both your examples are equivalent. However, the first one is less obvious and more "hacky", while the second one clearly states your intention.

int (*pointer)[280];
pointer = tab1;

pointer points to an 1D array of 280 integers. In your assignment, you actually assign the first row of tab1. This works since you can implicitly cast arrays to pointers (to the first element).

When you are using pointer[5][12], C treats pointer as an array of arrays (pointer[5] is of type int[280]), so there is another implicit cast here (at least semantically).

In your second example, you explicitly create a pointer to a 2D array:

int (*pointer)[100][280];
pointer = &tab1;

The semantics are clearer here: *pointer is a 2D array, so you need to access it using (*pointer)[i][j].

Both solutions use the same amount of memory (1 pointer) and will most likely run equally fast. Under the hood, both pointers will even point to the same memory location (the first element of the tab1 array), and it is possible that your compiler will even generate the same code.

The first solution is "more advanced" since one needs quite a deep understanding on how arrays and pointers work in C to understand what is going on. The second one is more explicit.

git-upload-pack: command not found, when cloning remote Git repo

Like Johan pointed out many times its .bashrc that's needed:

ln -s .bash_profile .bashrc

Setting the Vim background colors

Using set bg=dark with a white background can produce nearly unreadable text in some syntax highlighting schemes. Instead, you can change the overall colorscheme to something that looks good in your terminal. The colorscheme file should set the background attribute for you appropriately. Also, for more information see:

:h color

XPath: Get parent node from child node

New, improved answer to an old, frequently asked question...

How could I get its parent? Result should be the store node.

Use a predicate rather than the parent:: or ancestor:: axis

Most answers here select the title and then traverse up to the targeted parent or ancestor (store) element. A simpler, direct approach is to select parent or ancestor element directly in the first place, obviating the need to traverse to a parent:: or ancestor:: axes:

//*[book/title = "50"]

Should the intervening elements vary in name:

//*[*/title = "50"]

Or, in name and depth:

//*[.//title = "50"]

PHP/MySQL Insert null values

This is one example where using prepared statements really saves you some trouble.

In MySQL, in order to insert a null value, you must specify it at INSERT time or leave the field out which requires additional branching:

INSERT INTO table2 (f1, f2)
  VALUES ('String Value', NULL);

However, if you want to insert a value in that field, you must now branch your code to add the single quotes:

INSERT INTO table2 (f1, f2)
  VALUES ('String Value', 'String Value');

Prepared statements automatically do that for you. They know the difference between string(0) "" and null and write your query appropriately:

$stmt = $mysqli->prepare("INSERT INTO table2 (f1, f2) VALUES (?, ?)");
$stmt->bind_param('ss', $field1, $field2);

$field1 = "String Value";
$field2 = null;


It escapes your fields for you, makes sure that you don't forget to bind a parameter. There is no reason to stay with the mysql extension. Use mysqli and it's prepared statements instead. You'll save yourself a world of pain.

How to group by month from Date field using sql

I used the FORMAT function to accomplish this:

 FORMAT(Closing_Date, 'yyyy_MM') AS Closing_Month
 , count(*) cc 
 Defect_Status1 IS NOT NULL
 AND Closing_Date >= '2011-12-01'
 AND Closing_Date < '2016-07-01' 
GROUP BY FORMAT(Closing_Date, 'yyyy_MM')
ORDER BY Closing_Month

How can I list ALL DNS records?

There is no easy way to get all DNS records for a domain in one instance. You can only view certain records for example, if you wanna see an A record for a certain domain you can use the command: dig a(type of record) This is the same for all the other type of records you wanna see for that domain.

If your not familiar with the command line interface, you can also use a site like Wich is very handy tool for getting records of a domain.

I hope this answers your question.

How can I do an asc and desc sort using underscore.js?

Similar to Underscore library there is another library called as 'lodash' that has one method "orderBy" which takes in the parameter to determine in which order to sort it. You can use it like

_.orderBy('collection', 'propertyName', 'desc')

For some reason, it's not documented on the website docs.

Download File Using jQuery

I might suggest this, as a more gracefully degrading solution, using preventDefault:

$('a').click(function(e) {
    e.preventDefault();  //stop the browser from following
    window.location.href = 'uploads/file.doc';

<a href="no-script.html">Download now!</a>

Even if there's no Javascript, at least this way the user will get some feedback.

What is console.log?

You can view any messages logged to the console if you use a tool such as Firebug to inspect your code. Let's say you do this:

console.log('Testing console');

When you access the console in Firebug (or whichever tool you decide to use to inspect your code), you will see whatever message you told the function to log. This is particularly useful when you want to see if a function is executing, or if a variable is being passed/assigned properly. It's actually rather valuable for figuring out just what went wrong with your code.

JavaScript split String with white space

Using regex:

var str   = "my car is red";
var stringArray = str.split(/(\s+)/);

console.log(stringArray); // ["my", " ", "car", " ", "is", " ", "red"] 

\s matches any character that is a whitespace, adding the plus makes it greedy, matching a group starting with characters and ending with whitespace, and the next group starts when there is a character after the whitespace etc.

How do I load a file from resource folder?

ClassLoader loader = Thread.currentThread().getContextClassLoader();
InputStream is = loader.getResourceAsStream("test.csv");

If you use context ClassLoader to find a resource then definitely it will cost application performance.

Best way to save a trained model in PyTorch?

It depends on what you want to do.

Case # 1: Save the model to use it yourself for inference: You save the model, you restore it, and then you change the model to evaluation mode. This is done because you usually have BatchNorm and Dropout layers that by default are in train mode on construction:, filepath)

#Later to restore:

Case # 2: Save model to resume training later: If you need to keep training the model that you are about to save, you need to save more than just the model. You also need to save the state of the optimizer, epochs, score, etc. You would do it like this:

state = {
    'epoch': epoch,
    'state_dict': model.state_dict(),
    'optimizer': optimizer.state_dict(),
}, filepath)

To resume training you would do things like: state = torch.load(filepath), and then, to restore the state of each individual object, something like this:


Since you are resuming training, DO NOT call model.eval() once you restore the states when loading.

Case # 3: Model to be used by someone else with no access to your code: In Tensorflow you can create a .pb file that defines both the architecture and the weights of the model. This is very handy, specially when using Tensorflow serve. The equivalent way to do this in Pytorch would be:, filepath)

# Then later:
model = torch.load(filepath)

This way is still not bullet proof and since pytorch is still undergoing a lot of changes, I wouldn't recommend it.

How to reenable event.preventDefault?

You can re-activate the actions by adding

this.delegateEvents();  // Re-activates the events for all the buttons

If you add it to the render function of a backbone js view, then you can use event.preventDefault() as required.

Checking oracle sid and database name

As has been mentioned above,

select global_name from global_name;

is the way to go.

You couldn't query v$database/v$instance/v$thread because your user does not have the required permissions. You can grant them (via a DBA account) with:

grant select on v$database to <username here>;

Node.js request CERT_HAS_EXPIRED

I think the strictSSL: false should (should have worked, even in 2013) work. So in short are three possible ways:

  1. (obvious) Get your CA to renew the certificate, and put it on your server!
  2. Change the default settings of your request object:

    const myRequest = require('request').defaults({strictSSL: false})

    Many modules that use node-request internally also allow a request-object to be injected, so you can make them use your modified instance.
  3. (not recommended) Override all certificate checks for all HTTP(S) agent connections by setting the environment variable NODE_TLS_REJECT_UNAUTHORIZED=0 for the Node.js process.

How do you run your own code alongside Tkinter's event loop?

The solution posted by Bjorn results in a "RuntimeError: Calling Tcl from different appartment" message on my computer (RedHat Enterprise 5, python 2.6.1). Bjorn might not have gotten this message, since, according to one place I checked, mishandling threading with Tkinter is unpredictable and platform-dependent.

The problem seems to be that app.start() counts as a reference to Tk, since app contains Tk elements. I fixed this by replacing app.start() with a self.start() inside __init__. I also made it so that all Tk references are either inside the function that calls mainloop() or are inside functions that are called by the function that calls mainloop() (this is apparently critical to avoid the "different apartment" error).

Finally, I added a protocol handler with a callback, since without this the program exits with an error when the Tk window is closed by the user.

The revised code is as follows:

# Run tkinter code in another thread

import tkinter as tk
import threading

class App(threading.Thread):

    def __init__(self):

    def callback(self):

    def run(self):
        self.root = tk.Tk()
        self.root.protocol("WM_DELETE_WINDOW", self.callback)

        label = tk.Label(self.root, text="Hello World")


app = App()
print('Now we can continue running code while mainloop runs!')

for i in range(100000):

if statement checks for null but still throws a NullPointerException

The problem here is that in your code the program is calling 'null.length()' which is not defined if the argument passed to the function is null. That's why the exception is thrown.

git revert back to certain commit

git reset --hard 4a155e5 Will move the HEAD back to where you want to be. There may be other references ahead of that time that you would need to remove if you don't want anything to point to the history you just deleted.

Create a branch in Git from another branch

Various ways to create a branch in git from another branch:

This answer adds some additional insight, not already present in the existing answers, regarding just the title of the question itself (Create a branch in Git from another branch), but does not address the more narrow specifics of the question which already have sufficient answers here.

I'm adding this because I really needed to know how to do #1 below just now (create a new branch from a branch I do NOT have checked out), and it wasn't obvious how to do it, and Google searches led to here as a top search result. So, I'll share my findings here. This isn't touched upon well, if at all, by any other answer here.

While I'm at it, I'll also add my other most-common git branch commands I use in my regular workflow, below.

1. To create a new branch from a branch you do NOT have checked out:

Create branch2 from branch1 while you have any branch whatsoever checked out (ex: let's say you have master checked out):

git branch branch2 branch1

The general format is:

git branch <new_branch> [from_branch]

man git branch shows it as:

git branch [--track | --no-track] [-l] [-f] <branchname> [<start-point>]

2. To create a new branch from the branch you DO have checked out:

git branch new_branch

This is great for making backups before rebasing, squashing, hard resetting, etc.--before doing anything which could mess up your branch badly.

Ex: I'm on feature_branch1, and I'm about to squash 20 commits into 1 using git rebase -i master. In case I ever want to "undo" this, let's back up this branch first! I do this ALL...THE...TIME and find it super helpful and comforting to know I can always easily go back to this backup branch and re-branch off of it to try again in case I mess up feature_branch1 in the process:

git branch feature_branch1_BAK_20200814-1320hrs_about_to_squash

The 20200814-1120hrs part is the date and time in format YYYYMMDD-HHMMhrs, so that would be 13:20hrs (1:20pm) on 14 Aug. 2020. This way I have an easy way to find my backup branches until I'm sure I'm ready to delete them. If you don't do this and you mess up badly, you have to use git reflog to go find your branch prior to messing it up, which is much harder, more stressful, and more error-prone.

3. To create and check out a new branch from the branch you DO have checked out:

git checkout -b new_branch

4. To rename a branch

Just like renaming a regular file or folder in the terminal, git considered "renaming" to be more like a 'm'ove command, so you use git branch -m to rename a branch. Here's the general format:

git branch -m <old_name> <new_name>

man git branch shows it like this:

git branch (-m | -M) [<oldbranch>] <newbranch>

Example: let's rename branch_1 to branch_1.5:

git branch -m branch_1 branch_1.5

Combine two integer arrays

Task: Given two int arrays array1 and array2 of the same length, zip should return an array that's twice as long, in which the elements of array1 and array2 are interleaved. That is, element #0 of the result array is array1[0], element #1 is array2[0], element #2 is array1[1], element #3 is array2[1], and so on.

public static int [] zip(int [ ] array1, int [] array2) {
//make sure both arrays have same length
if (array1.length != array2.length) {
    throw new IllegalArgumentException("Unequal array lengths - zip not possible");

int [] zippedArray = new int [array1.length+ array2.length]; 
int idx_1 = 0;
int idx_2 = 0;

//for each element of first array, add to new array if index of new array is even

for (int i=0; i < zippedArray.length; i+=2){
    zippedArray[i]= array1[idx_1++];
for (int i=1; i < zippedArray.length; i+=2){
    zippedArray[i]= array2[idx_2++];

//check contents of new array       
for (int item: zippedArray){
    System.out.print(item + " ");

return zippedArray;


MySQL LIMIT on DELETE statement

First I struggled a bit with a DELETE FROM ... USING ... WHERE query,... Since i wanted to test first so i tried with SELECT FROM ... USING... WHERE ... and this caused an error , ... Then i wanted to reduce the number of deletions adding
LIMIT 10 which also produced an error Then i removed the "LIMIT" and - hurray - it worked: "1867 rows deleted. (Query took 1.3025 seconds.)"

The query was:

USING tableX , tableX as Dup 
WHERE NOT tableX .id = 
 AND tableX .id > 
 AND tableX .email= 
 AND tableX .mobil = Dup.mobil

This worked.

python capitalize first letter only

You can replace the first letter (preceded by a digit) of each word using regex:

re.sub(r'(\d\w)', lambda w:, '1bob 5sandy')

 1Bob 5Sandy

What is the difference between hg forget and hg remove?

A file can be tracked or not, you use hg add to track a file and hg remove or hg forget to un-track it. Using hg remove without flags will both delete the file and un-track it, hg forget will simply un-track it without deleting it.

X-Frame-Options: ALLOW-FROM in firefox and chrome

ALLOW-FROM is not supported in Chrome or Safari. See MDN article:

You are already doing the work to make a custom header and send it with the correct data, can you not just exclude the header when you detect it is from a valid partner and add DENY to every other request? I don't see the benefit of AllowFrom when you are already dynamically building the logic up?

printf, wprintf, %s, %S, %ls, char* and wchar*: Errors not announced by a compiler warning?

%S seems to conform to The Single Unix Specification v2 and is also part of the current (2008) POSIX specification.

Equivalent C99 conforming format specifiers would be %s and %ls.

How do you list all triggers in a MySQL database?

You can use below to find a particular trigger definition.

SHOW TRIGGERS LIKE '%trigger_name%'\G

or the below to show all the triggers in the database. It will work for MySQL 5.0 and above.


Merging two CSV files using Python

When I'm working with csv files, I often use the pandas library. It makes things like this very easy. For example:

import pandas as pd

a = pd.read_csv("filea.csv")
b = pd.read_csv("fileb.csv")
b = b.dropna(axis=1)
merged = a.merge(b, on='title')
merged.to_csv("output.csv", index=False)

Some explanation follows. First, we read in the csv files:

>>> a = pd.read_csv("filea.csv")
>>> b = pd.read_csv("fileb.csv")
>>> a
   title  stage    jan    feb
0   darn  3.001  0.421  0.532
1     ok  2.829  1.036  0.751
2  three  1.115  1.146  2.921
>>> b
   title    mar    apr    may       jun  Unnamed: 5
0   darn  0.631  1.321  0.951    1.7510         NaN
1     ok  1.001  0.247  2.456    0.3216         NaN
2  three  0.285  1.283  0.924  956.0000         NaN

and we see there's an extra column of data (note that the first line of fileb.csv -- title,mar,apr,may,jun, -- has an extra comma at the end). We can get rid of that easily enough:

>>> b = b.dropna(axis=1)
>>> b
   title    mar    apr    may       jun
0   darn  0.631  1.321  0.951    1.7510
1     ok  1.001  0.247  2.456    0.3216
2  three  0.285  1.283  0.924  956.0000

Now we can merge a and b on the title column:

>>> merged = a.merge(b, on='title')
>>> merged
   title  stage    jan    feb    mar    apr    may       jun
0   darn  3.001  0.421  0.532  0.631  1.321  0.951    1.7510
1     ok  2.829  1.036  0.751  1.001  0.247  2.456    0.3216
2  three  1.115  1.146  2.921  0.285  1.283  0.924  956.0000

and finally write this out:

>>> merged.to_csv("output.csv", index=False)



how to select rows based on distinct values of A COLUMN only

Looking at your output maybe the following query can work, give it a try:

SELECT * FROM tablename
(SELECT MIN(id) FROM tablename GROUP BY EmailAddress)

This will select only one row for each distinct email address, the row with the minimum id which is what your result seems to portray

Get div tag scroll position using JavaScript

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">
<html xmlns="">
<head runat="server">
    <script type="text/javascript">
        function scollPos() {
            var div = document.getElementById("myDiv").scrollTop;
            document.getElementById("pos").innerHTML = div;
    <form id="form1">
    <div id="pos">
    <div id="myDiv" style="overflow: auto; height: 200px; width: 200px;" onscroll="scollPos();">
        Place some large content here

How can I escape a double quote inside double quotes?

Store the double quote character in a variable:

echo "Double quotes ${dqt}X${dqt} inside a double quoted string"


Double quotes "X" inside a double quoted string

Set content of iframe

You want to be using the iframe's srcdoc attribute for that (MDN documentation).

var html_string = "<html><body><h1>My epic iframe</p></body></html>";
document.querySelector('iframe').srcdoc = html_string;

The nice thing about using this method over for example Red's method listed on this page, is that iframe contents added with srcdoc are seen as the same-origin. That way can continue to manipulate and access the iframe with JavaScript if you wish.

How to plot two columns of a pandas data frame using points?

You can specify the style of the plotted line when calling df.plot:

df.plot(x='col_name_1', y='col_name_2', style='o')

The style argument can also be a dict or list, e.g.:

import numpy as np
import pandas as pd

d = {'one' : np.random.rand(10),
     'two' : np.random.rand(10)}

df = pd.DataFrame(d)


All the accepted style formats are listed in the documentation of matplotlib.pyplot.plot.


How can I join multiple SQL tables using the IDs?

You want something more like this:

SELECT TableA.*, TableB.*, TableC.*, TableD.*
    JOIN TableB
        ON TableB.aID = TableA.aID
    JOIN TableC
        ON TableC.cID = TableB.cID
    JOIN TableD
        ON TableD.dID = TableA.dID

In your example, you are not actually including TableD. All you have to do is perform another join just like you have done before.

A note: you will notice that I removed many of your parentheses, as they really are not necessary in most of the cases you had them, and only add confusion when trying to read the code. Proper nesting is the best way to make your code readable and separated out.

UIView Hide/Show with animation

I use this little Swift 3 extension:

extension UIView {

  func fadeIn(duration: TimeInterval = 0.5,
              delay: TimeInterval = 0.0,
              completion: @escaping ((Bool) -> Void) = {(finished: Bool) -> Void in }) {
    UIView.animate(withDuration: duration,
                   delay: delay,
                   options: UIViewAnimationOptions.curveEaseIn,
                   animations: {
      self.alpha = 1.0
    }, completion: completion)

  func fadeOut(duration: TimeInterval = 0.5,
               delay: TimeInterval = 0.0,
               completion: @escaping (Bool) -> Void = {(finished: Bool) -> Void in }) {
    UIView.animate(withDuration: duration,
                   delay: delay,
                   options: UIViewAnimationOptions.curveEaseIn,
                   animations: {
      self.alpha = 0.0
    }, completion: completion)

how to stop a running script in Matlab

To add on:

you can insert a time check within a loop with intensive or possible deadlock, ie.


where within this section

if (toc > timeRequiredToBreakOff)     % time conditional break off
      % other options may be:                         
      % 1. display intermediate values with pause;
      % 2. exit;                           % in some cases, extreme : kill/ quit matlab

Why is division in Ruby returning an integer instead of decimal value?

It’s doing integer division. You can use to_f to force things into floating-point mode:

9.to_f / 5  #=> 1.8
9 / 5.to_f  #=> 1.8

This also works if your values are variables instead of literals. Converting one value to a float is sufficient to coerce the whole expression to floating point arithmetic.

How do I send a cross-domain POST request via JavaScript?

Check the post_method function in - a good example for the iframe method described above.

How to use SortedMap interface in Java?

A TreeMap is probably the most straightforward way of doing this. You use it exactly like a normal Map. i.e.

Map<Float,String> mySortedMap = new TreeMap<Float,MyObject>();
// Put some values in it

// Iterate through it and it'll be in order!
for(Map.Entry<Float,String> entry : mySortedMap.entrySet()) {
} // outputs Zero One Three 

It's worth taking a look at the API docs, to see what else you can do with it.

Cannot connect to repo with TortoiseSVN

SVN is case-sensitive. Make sure that you're spelling it properly. If it got renamed, you can relocate the working folder to the new URL. See

JQUERY: Uncaught Error: Syntax error, unrecognized expression



your solution is passing the double quotes as part of the string.

Date vs DateTime

No there isn't. DateTime represents some point in time that is composed of a date and a time. However, you can retrieve the date part via the Date property (which is another DateTime with the time set to 00:00:00).

And you can retrieve individual date properties via Day, Month and Year.

how to insert value into DataGridView Cell?

For Some Reason I could Not add Numbers(in string Format) to the DataGridView But This Worked For Me Hope it help someone!

//dataGridView1.Rows[RowCount].Cells[0].Value = FEString3;//This was not adding Stringed Numbers like "1","2","3"....
DataGridViewCell NewCell = new DataGridViewTextBoxCell();//Create New Cell
NewCell.Value = FEString3;//Set Cell Value
DataGridViewRow NewRow = new DataGridViewRow();//Create New Row
NewRow.Cells.Add(NewCell);//Add Cell to Row
dataGridView1.Rows.Add(NewRow);//Add Row To Datagrid

Install Android App Bundle on device

If you want to install apk from your aab to your device for testing purpose then you need to edit the configuration before running it on the connected device.

  1. Go to Edit Configurations
    enter image description here
  2. Select the Deploy dropdown and change it from "Default apk" to "APK from app bundle".enter image description here
  3. Apply the changes and then run it on the device connected. Build time will increase after making this change.

This will install an apk directly on the device connected from the aab.

Difference between java.exe and javaw.exe

java.exe is the command where it waits for application to complete untill it takes the next command. javaw.exe is the command which will not wait for the application to complete. you can go ahead with another commands.

What's the difference between Visual Studio Community and other, paid versions?

There are 2 major differences.

  1. Technical
  2. Licensing

Technical, there are 3 major differences:

First and foremost, Community doesn't have TFS support.
You'll just have to use git (arguable whether this constitutes a disadvantage or whether this actually is a good thing).
Note: This is what MS wrote. Actually, you can check-in&out with TFS as normal, if you have a TFS server in the network. You just cannot use Visual Studio as TFS SERVER.

Second, VS Community is severely limited in its testing capability.
Only unit tests. No Performance tests, no load tests, no performance profiling.

Third, VS Community's ability to create Virtual Environments has been severely cut.

On the other hand, syntax highlighting, IntelliSense, Step-Through debugging, GoTo-Definition, Git-Integration and Build/Publish are really all the features I need, and I guess that applies to a lot of developers.

For all other things, there are tools that do the same job faster, better and cheaper.

If you, like me, anyway use git, do unit testing with NUnit, and use Java-Tools to do Load-Testing on Linux plus TeamCity for CI, VS Community is more than sufficient, technically speaking.


A) If you're an individual developer (no enterprise, no organization), no difference (AFAIK), you can use CommunityEdition like you'd use the paid edition (as long as you don't do subcontracting)
B) You can use CommunityEdition freely for OpenSource (OSI) projects
C) If you're an educational insitution, you can use CommunityEdition freely (for education/classroom use)
D) If you're an enterprise with 250 PCs or users or more than one million US dollars in revenue (including subsidiaries), you are NOT ALLOWED to use CommunityEdition.
E) If you're not an enterprise as defined above, and don't do OSI or education, but are an "enterprise"/organization, with 5 or less concurrent (VS) developers, you can use VS Community freely (but only if you're the owner of the software and sell it, not if you're a subcontractor creating software for a larger enterprise, software which in the end the enterprise will own), otherwise you need a paid edition.

The above does not consitute legal advise.
See also:

Creating and Update Laravel Eloquent

like @JuanchoRamone posted above (thank @Juancho) it's very useful for me, but if your data is array you should modify a little like this:

public static function createOrUpdate($data, $keys) {
    $record = self::where($keys)->first();
    if (is_null($record)) {
        return self::create($data);
    } else {
        return $record->update($data);

Construct a manual legend for a complicated plot

You need to map attributes to aesthetics (colours within the aes statement) to produce a legend.

cols <- c("LINE1"="#f04546","LINE2"="#3591d1","BAR"="#62c76b")
ggplot(data=data,aes(x=a)) + 
  geom_bar(stat="identity", aes(y=h, fill = "BAR"),colour="#333333")+ #green
  geom_line(aes(y=b,group=1, colour="LINE1"),size=1.0) +   #red
  geom_point(aes(y=b, colour="LINE1"),size=3) +           #red
  geom_errorbar(aes(ymin=d, ymax=e, colour="LINE1"), width=0.1, size=.8) + 
  geom_line(aes(y=c,group=1,colour="LINE2"),size=1.0) +   #blue 
  geom_point(aes(y=c,colour="LINE2"),size=3) +           #blue
  geom_errorbar(aes(ymin=f, ymax=g,colour="LINE2"), width=0.1, size=.8) + 
  scale_colour_manual(name="Error Bars",values=cols) + scale_fill_manual(name="Bar",values=cols) +
  ylab("Symptom severity") + xlab("PHQ-9 symptoms") +
  ylim(0,1.6) +
  theme_bw() +
  theme(axis.title.x = element_text(size = 15, vjust=-.2)) +
  theme(axis.title.y = element_text(size = 15, vjust=0.3))

enter image description here

I understand where Roland is coming from, but since this is only 3 attributes, and complications arise from superimposing bars and error bars this may be reasonable to leave the data in wide format like it is. It could be slightly reduced in complexity by using geom_pointrange.

To change the background color for the error bars legend in the original, add + theme(legend.key = element_rect(fill = "white",colour = "white")) to the plot specification. To merge different legends, you typically need to have a consistent mapping for all elements, but it is currently producing an artifact of a black background for me. I thought guide = guide_legend(fill = NULL,colour = NULL) would set the background to null for the legend, but it did not. Perhaps worth another question.

ggplot(data=data,aes(x=a)) + 
  geom_bar(stat="identity", aes(y=h,fill = "BAR", colour="BAR"))+ #green
  geom_line(aes(y=b,group=1, colour="LINE1"),size=1.0) +   #red
  geom_point(aes(y=b, colour="LINE1", fill="LINE1"),size=3) +           #red
  geom_errorbar(aes(ymin=d, ymax=e, colour="LINE1"), width=0.1, size=.8) + 
  geom_line(aes(y=c,group=1,colour="LINE2"),size=1.0) +   #blue 
  geom_point(aes(y=c,colour="LINE2", fill="LINE2"),size=3) +           #blue
  geom_errorbar(aes(ymin=f, ymax=g,colour="LINE2"), width=0.1, size=.8) + 
  scale_colour_manual(name="Error Bars",values=cols, guide = guide_legend(fill = NULL,colour = NULL)) + 
  scale_fill_manual(name="Bar",values=cols, guide="none") +
  ylab("Symptom severity") + xlab("PHQ-9 symptoms") +
  ylim(0,1.6) +
  theme_bw() +
  theme(axis.title.x = element_text(size = 15, vjust=-.2)) +
  theme(axis.title.y = element_text(size = 15, vjust=0.3))

enter image description here

To get rid of the black background in the legend, you need to use the override.aes argument to the guide_legend. The purpose of this is to let you specify a particular aspect of the legend which may not be being assigned correctly.

ggplot(data=data,aes(x=a)) + 
  geom_bar(stat="identity", aes(y=h,fill = "BAR", colour="BAR"))+ #green
  geom_line(aes(y=b,group=1, colour="LINE1"),size=1.0) +   #red
  geom_point(aes(y=b, colour="LINE1", fill="LINE1"),size=3) +           #red
  geom_errorbar(aes(ymin=d, ymax=e, colour="LINE1"), width=0.1, size=.8) + 
  geom_line(aes(y=c,group=1,colour="LINE2"),size=1.0) +   #blue 
  geom_point(aes(y=c,colour="LINE2", fill="LINE2"),size=3) +           #blue
  geom_errorbar(aes(ymin=f, ymax=g,colour="LINE2"), width=0.1, size=.8) + 
  scale_colour_manual(name="Error Bars",values=cols, 
                      guide = guide_legend(override.aes=aes(fill=NA))) + 
  scale_fill_manual(name="Bar",values=cols, guide="none") +
  ylab("Symptom severity") + xlab("PHQ-9 symptoms") +
  ylim(0,1.6) +
  theme_bw() +
  theme(axis.title.x = element_text(size = 15, vjust=-.2)) +
  theme(axis.title.y = element_text(size = 15, vjust=0.3))

enter image description here

How do I get the current location of an iframe?

Ok, so in this application, there is an iframe in which the user is supplied with links or some capacity that allows that iframe to browse to some external site. You are then looking to capture the URL to which the user has browsed.

Something to keep in mind. Since the URL is to an external source, you will be limited in how much you can interact with this iframe via javascript (or an client side access for that matter), this is known as browser cross-domain security, as apparently you have discovered. There are clever work arounds, as presented here Cross-domain, cross-frame Javascript, although I do not think this work around applies in this case.

About all you can access is the location, as you need.

I would suggest making the code presented more resilitant and less error prone. Try browsing the web sometime with IE or FF configured to show javascript errors. You will be surprised just how many javascript errors are thrown, largely because there is a lot of error prone javascript out there, which just continues to proliferate.

This solution assumes that the iframe in question is the same "window" context where you are running the javascript. (Meaning, it is not embedded within another frame or iframe, in which case, the javascript code gets more involved, and you likely need to recursively search through the window hierarchy.)

<iframe name='frmExternal' id='frmExternal' src=''></frame>
<input type='text' id='txtUrl' />
<input type='button' id='btnGetUrl' value='Get URL' onclick='GetIFrameUrl();' />

<script language='javascript' type='text/javascript'>
function GetIFrameUrl()
    if (!document.getElementById)

    var frm = document.getElementById("frmExternal");
    var txt = document.getElementById("txtUrl");

    if (frm == null || txt == null)
        // not great user feedback but slightly better than obnoxious script errors
       alert("There was a problem with this page, please refresh.");

    txt.value = frm.src;

Hope this helps.

Waiting on a list of Future

The CompletionService will take your Callables with the .submit() method and you can retrieve the computed futures with the .take() method.

One thing you must not forget is to terminate the ExecutorService by calling the .shutdown() method. Also you can only call this method when you have saved a reference to the executor service so make sure to keep one.

Example code - For a fixed number of work items to be worked on in parallel:

ExecutorService service = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());

CompletionService<YourCallableImplementor> completionService = 
new ExecutorCompletionService<YourCallableImplementor>(service);

ArrayList<Future<YourCallableImplementor>> futures = new ArrayList<Future<YourCallableImplementor>>();

for (String computeMe : elementsToCompute) {
    futures.add(completionService.submit(new YourCallableImplementor(computeMe)));
//now retrieve the futures after computation (auto wait for it)
int received = 0;

while(received < elementsToCompute.size()) {
 Future<YourCallableImplementor> resultFuture = completionService.take(); 
 YourCallableImplementor result = resultFuture.get();
 received ++;
//important: shutdown your ExecutorService

Example code - For a dynamic number of work items to be worked on in parallel:

public void runIt(){
    ExecutorService service = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
    CompletionService<CallableImplementor> completionService = new ExecutorCompletionService<CallableImplementor>(service);
    ArrayList<Future<CallableImplementor>> futures = new ArrayList<Future<CallableImplementor>>();

    //Initial workload is 8 threads
    for (int i = 0; i < 9; i++) {
        futures.add(completionService.submit( CallableImplementor()));             
    boolean finished = false;
    while (!finished) {
        try {
            Future<CallableImplementor> resultFuture;
            resultFuture = completionService.take();
            CallableImplementor result = resultFuture.get();
            finished = doSomethingWith(result.getResult());
            result = null;
            resultFuture = null;
            //After work package has been finished create new work package and add it to futures
            futures.add(completionService.submit( CallableImplementor()));
        } catch (InterruptedException | ExecutionException e) {
            //handle interrupted and assert correct thread / work packet count              

    //important: shutdown your ExecutorService

public class CallableImplementor implements Callable{
    boolean result;

    public CallableImplementor call() throws Exception {
        //business logic goes here
        return this;

    public boolean getResult() {
        return result;

    public void setResult(boolean result) {
        this.result = result;

Registry Key '...' has value '1.7', but '1.6' is required. Java 1.7 is Installed and the Registry is Pointing to it

The jar was compiled to be 1.6 compliant. That is why you get this error. Two resolutions:
1) Use Java 1.6


2) Recompile the jar to be compliant for your environment 1.7

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.

How do I read the contents of a Node.js stream into a string variable?

From the nodejs documentation you should do this - always remember a string without knowing the encoding is just a bunch of bytes:

var readable = getReadableStreamSomehow();
readable.on('data', function(chunk) {
  assert.equal(typeof chunk, 'string');
  console.log('got %d characters of string data', chunk.length);
}) Need Text Box to Only Accept Numbers

You Can use Follow code Textbox Keypress Event:

Private Sub txtbox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles txtbox1.KeyPress
        If Val(txtbox1.text) < 10 Then
            If Char.IsLetterOrDigit(e.KeyChar) = False And Char.IsControl(e.KeyChar) = False Then
                e.Handled = True
            End If
            e.Handled = True
        End If
    Catch ex As Exception
        ShowException(ex.Message, MESSAGEBOX_TITLE, ex)
    End Try
End Sub

This code allow numbers only and you can enter only number between 1 to 10.

Finding height in Binary Search Tree

This is untested, but fairly obviously correct:

private int findHeight(Treenode<T> aNode) {
  if (aNode.left == null && aNode.right == null) {
    return 0; // was 1; apparently a node with no children has a height of 0.
  } else if (aNode.left == null) {
    return 1 + findHeight(aNode.right);
  } else if (aNode.right == null) {
    return 1 + findHeight(aNode.left);
  } else {
    return 1 + max(findHeight(aNode.left), findHeight(aNode.right));

Often simplifying your code is easier than figuring out why it's off by one. This code is easy to understand: the four possible cases are clearly handled in an obviously correct manner:

  • If both the left and right trees are null, return 0, since a single node by definition has a height of 0. (was 1)
  • If either the left or right trees (but not both!) are null, return the height of the non-null tree, plus 1 to account for the added height of the current node.
  • If neither tree is null, return the height of the taller subtree, again plus one for the current node.

Sending email through Gmail SMTP server with C#

This code works for me, and also allows in gmail access from unsecure apps, and removing authentication in 2 steps:

Host = "",
Port = 587,
EnableSsl = true,
DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network,
UseDefaultCredentials = false,
Credentials = new NetworkCredential(MailAddress, Password)

SQLite DateTime comparison

Following worked for me.

FROM table_log
WHERE DATE(start_time) <= '2017-01-09' AND DATE(start_time) >= '2016-12-21'

Random numbers with Math.random() in Java

Math.random() generates a number between 0 (inclusive) and 1 (exclusive).

So (int)(Math.random() * max) ranges from 0 to max-1 inclusive.

Then (int)(Math.random() * max) + min ranges from min to max + min - 1, which is not what you want.

Google's formula is correct.

printing out a 2-D array in Matrix format

    int[][] matrix = {
    //use foreach loop as below to avoid IndexOutOfBoundException
    //need to check matrix != null if implements as a method
    //for each row in the matrix
    for (int[] row : matrix) {
        //for each number in the row
        for (int j : row) {
            System.out.print(j + " ");

Regex to remove letters, symbols except numbers


var removedText = self.val().replace(/[^0-9]+/, '');

^ - means NOT

How can moment.js be imported with typescript?

1. install moment

npm install moment --save

2. test this code in your typescript file

import moment = require('moment');


Compare two files and write it to "match" and "nomatch" files

//STEP01   EXEC SORT90MB                        
//            DISP=SHR                          
//            DISP=SHR                          
//            DISP=(,CATLG,DELETE),             
//            UNIT=TAPE,                        
//            DCB=(RECFM=FB,BLKSIZE=0),         
//            DSORG=PS                          
//SYSOUT   DD SYSOUT=*                          
//SYSIN    DD *                                 
  JOINKEYS FILE=F1,FIELDS=(1,79,A)              
  JOINKEYS FILE=F2,FIELDS=(1,79,A)              
  JOIN UNPAIRED,F1,ONLY                         
  SORT FIELDS=COPY                              

load csv into 2D matrix with numpy for plotting

Pure numpy

numpy.loadtxt(open("test.csv", "rb"), delimiter=",", skiprows=1)

Check out the loadtxt documentation.

You can also use python's csv module:

import csv
import numpy
reader = csv.reader(open("test.csv", "rb"), delimiter=",")
x = list(reader)
result = numpy.array(x).astype("float")

You will have to convert it to your favorite numeric type. I guess you can write the whole thing in one line:

result = numpy.array(list(csv.reader(open("test.csv", "rb"), delimiter=","))).astype("float")

Added Hint:

You could also use and get the associated numpy array which can be faster.

Replace a newline in TSQL

In SQL Server 2017 & later, use Trim

Select Trim(char(10) + char(13) from @str)
  1. it trims on starting and ending, not in the middle
  2. the order of \r and \n does not matter

I use it to trim special characters for a file name

Select Trim(char(10) + char(13) + ' *<>' from @fileName)

Removing the textarea border in HTML

This one is great:

<style type="text/css">
width: 100%;
height: 100%;
border-color: Transparent;     
<textarea class="test"></textarea>

Example: Communication between Activity and Service using Messaging

Great tutorial, fantastic presentation. Neat, simple, short and very explanatory. Although, notification.setLatestEventInfo(this, getText(R.string.service_label), text, contentIntent); method is no more. As trante stated here, good approach would be:

private static final int NOTIFICATION_ID = 45349;

private void showNotification() {
    NotificationCompat.Builder builder =
            new NotificationCompat.Builder(this)
                    .setContentTitle("My Notification Title")
                    .setContentText("Something interesting happened");

    Intent targetIntent = new Intent(this, MainActivity.class);
    PendingIntent contentIntent = PendingIntent.getActivity(this, 0, targetIntent, PendingIntent.FLAG_UPDATE_CURRENT);
    _nManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

public void onDestroy() {
    if (_timer != null) {_timer.cancel();}
    _nManager.cancel(NOTIFICATION_ID); // Cancel the persistent notification.
    Log.i("PlaybackService", "Service Stopped.");
    _isRunning = false;

Checked myself, everything works like a charm (activity and service names may differ from original).

How to convert an array to a string in PHP?

PHP's implode function can be used to convert an array into a string --- it is similar to join in other languages.

You can use it like so:

$string_product = implode(',', $array);

With an array like [1, 2, 3], this would result in a string like "1,2,3".


To avoid x !instance of Long prob Add

<property name="openjpa.Compatibility" value="StrictIdentityValues=false"/>

in your persistence.xml

How to count frequency of characters in a string?

*import java.util.ArrayList;
import java.util.Collections;

public class Freq {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String temp="zsaaqaaaaaaaabbbbbcc";
    List<String> temp1= new ArrayList<String> ();
    ArrayList<Integer>freq=new ArrayList<Integer>();
    for(int i=0;i<temp.length()-1;i++)
    Set<String> uniqset=new HashSet<String>(temp1);
    for(String s:uniqset)
        freq.add(Collections.frequency(temp1, s));
        System.out.println(s+" -->>"+Collections.frequency(temp1, s));

       a -->>10
       b -->>5
       c -->>1
       q -->>1
       s -->>1
       z -->>1

Use collections frequency method to count frequency of char*

C++ - Assigning null to a std::string

The else case is unncecessary, when you create a string object it is empty by default.

Converting an int to a binary string representation in Java?

public class Main  {

   public static String toBinary(int n, int l ) throws Exception {
       double pow =  Math.pow(2, l);
       StringBuilder binary = new StringBuilder();
        if ( pow < n ) {
            throw new Exception("The length must be big from number ");
       int shift = l- 1;
       for (; shift >= 0 ; shift--) {
           int bit = (n >> shift) & 1;
           if (bit == 1) {
           } else {
       return binary.toString();

    public static void main(String[] args) throws Exception {
        System.out.println(" binary = " + toBinary(7, 4));
        System.out.println(" binary = " + Integer.toString(7,2));

JavaScript Chart Library

Check out !

Highcharts is a charting library written in pure JavaScript, offering an easy way of adding interactive charts to your web site or web application. Highcharts currently supports line, spline, area, areaspline, column, bar, pie and scatter chart types.

How do I sort a list of datetime or date objects?

You're getting None because list.sort() it operates in-place, meaning that it doesn't return anything, but modifies the list itself. You only need to call a.sort() without assigning it to a again.

There is a built in function sorted(), which returns a sorted version of the list - a = sorted(a) will do what you want as well.

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

Two options save vijay.sql

execute immediate 
SELECT wk.*,bbc.distance_km ,NVL(bbc.tactical_broadband_offer,0) tactical_broadband_offer ,
FROM   spineowner.pop_wkly_refresh_20100201 wk,
       dms_bb_coverage_102009 bbc,
       dms_select_executive_group sel,
       DMS_RESIGN_CAMPAIGN_26052009 res,
       DMS_PRIORITY_CLUB pclub
WHERE  wk.mpn = bbc.mpn(+)
AND    wk.mpn = sel.mpn (+)
AND    wk.mpn = res.mpn (+)
AND    wk.mpn = pclub.mpn (+)'

The above will generate table names automatically based on sysdate. If you still need to pass as variable, then save vijay.sql as

execute immediate 
SELECT wk.*,bbc.distance_km ,NVL(bbc.tactical_broadband_offer,0) tactical_broadband_offer ,
FROM   spineowner.pop_wkly_refresh_20100201 wk,
       dms_bb_coverage_102009 bbc,
       dms_select_executive_group sel,
       DMS_RESIGN_CAMPAIGN_26052009 res,
       DMS_PRIORITY_CLUB pclub
WHERE  wk.mpn = bbc.mpn(+)
AND    wk.mpn = sel.mpn (+)
AND    wk.mpn = res.mpn (+)
AND    wk.mpn = pclub.mpn (+)'

and then run as sqlplus -s username/password @vijay.sql '20100101'

Print range of numbers on same line

Use end = " ", inside the print function


for x in range(1,11):
       print(x,end = " ")

EC2 instance has no public DNS

After verifying VPC and Subnet settings, my EC2 instance still didn't have a public DNS. After a day of searching for a resolution, I finally figured it out.

I had to create a new Elastic IP address, then associate it to my instance.

From the EC2 Dashboard:

Go to Elastic IPs from the sidebar.

Click Allocate new address, then Allocate.

Go back to the EC2 Dashboard. Go to Network Interfaces.

Select the EC2 instance without a public DNS. Then Actions - Associate Address.

The Address field, select the new elastic IP address.

The Associate to private IP address field, select the private IP address with no public DNS.

Click Associate Address.

Your EC2 instance should now have a public DNS.

How do I convert a Python program to a runnable .exe Windows program?

Understand that every 'freezing' application for Python will not really secure your code in any way. Every packaging system for a stand-alone executable Python 'program' will include a lot of the Python libraries and interpreter, which will make your program pretty large.

That said, PyInstaller has done a nearly flawless job with everything I've thrown at it. Currently it only supports up to Python 2.7 but Pyinstaller's support for a varied set of libraries large and small is unmatched in other 'freeze' type programs for Python.

How does one make random number between range for arc4random_uniform()?

I've made an Int type extension. tested it in playground, hope this is useful. It also accepts negative ranges:

extension Int
    static func random(range: Range<Int> ) -> Int
        var offset = 0

        if range.startIndex < 0   // allow negative ranges
            offset = abs(range.startIndex)

        let mini = UInt32(range.startIndex + offset)
        let maxi = UInt32(range.endIndex   + offset)

        return Int(mini + arc4random_uniform(maxi - mini)) - offset

use like

var aRandomInt = Int.random(-500...100)  // returns a random number within the given range.

or define it as a Range extension as property like this:

extension Range
    var randomInt: Int
            var offset = 0

            if (startIndex as Int) < 0   // allow negative ranges
                offset = abs(startIndex as Int)

            let mini = UInt32(startIndex as Int + offset)
            let maxi = UInt32(endIndex   as Int + offset)

            return Int(mini + arc4random_uniform(maxi - mini)) - offset

// usage example: get an Int within the given Range:
let nr = (-1000 ... 1100).randomInt

MYSQL Truncated incorrect DOUBLE value

Try replacing the AND with ,

UPDATE shop_category 
SET name = 'Secolul XVI - XVIII', name_eng = '16th to 18th centuries' 
WHERE category_id = 4768

The UPDATE Syntax shows comma should be used as the separator.

How can I set / change DNS using the command-prompt at windows 8

Now you can change the primary dns (index=1), assuming that your interface is static (not using dhcp)

You can set your DNS servers statically even if you use DHCP to obtain your IP address.

Example under Windows 7 to add two DN servers, the command is as follows:

netsh interface ipv4 add dns "Local Area Connection" address=192.168.x.x index=1 netsh interface ipv4 add dns "Local Area Connection" address=192.168.x.x index=2

How do I convert a dictionary to a JSON String in C#?

Simple One-Line Answer

(using System.Web.Script.Serialization )

This code will convert any Dictionary<Key,Value> to Dictionary<string,string> and then serialize it as a JSON string:

var json = new JavaScriptSerializer().Serialize(yourDictionary.ToDictionary(item => item.Key.ToString(), item => item.Value.ToString()));

It is worthwhile to note that something like Dictionary<int, MyClass> can also be serialized in this way while preserving the complex type/object.

Explanation (breakdown)

var yourDictionary = new Dictionary<Key,Value>(); //This is just to represent your current Dictionary.

You can replace the variable yourDictionary with your actual variable.

var convertedDictionary = yourDictionary.ToDictionary(item => item.Key.ToString(), item => item.Value.ToString()); //This converts your dictionary to have the Key and Value of type string.

We do this, because both the Key and Value has to be of type string, as a requirement for serialization of a Dictionary.

var json = new JavaScriptSerializer().Serialize(convertedDictionary); //You can then serialize the Dictionary, as both the Key and Value is of type string, which is required for serialization.

Comparison of full text search engine - Lucene, Sphinx, Postgresql, MySQL?

Just my two cents to this very old question. I would highly recommend taking a look at ElasticSearch.

Elasticsearch is a search server based on Lucene. It provides a distributed, multitenant-capable full-text search engine with a RESTful web interface and schema-free JSON documents. Elasticsearch is developed in Java and is released as open source under the terms of the Apache License.

The advantages over other FTS (full text search) Engines are:

  • RESTful interface
  • Better scalability
  • Large community
  • Built by Lucene developers
  • Extensive documentation
  • There are many open source libraries available (including Django)

We are using this search engine at our project and very happy with it.

HTML / CSS How to add image icon to input type="button"?

What it looks like

This works well for me, and I'm handling hover and click CSS as well (by changing background color):

HTML (here showing 2 images, image1 on top of image2):

<button class="iconButton" style="background-image: url('image1.png'), url('image2.png')"

CSS (my images are 32px X 32px, so I gave them 4px for padding and a 5px border rounding):

.iconButton {
    width: 36px;
    height: 36px;
    background-color: #000000;
    background-position: center;
    background-repeat: no-repeat;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    outline: none;

.iconButton:hover {
    background-color: #303030;

.iconButton:active {
    background-color: #606060;

button::-moz-focus-inner {
    border: 0;

C pointer to array/array of pointers disambiguation

As a rule of thumb, right unary operators (like [], (), etc) take preference over left ones. So, int *(*ptr)()[]; would be a pointer that points to a function that returns an array of pointers to int (get the right operators as soon as you can as you get out of the parenthesis)

Automatically create requirements.txt

if you are using PyCharm, when you open or clone the project into the PyCharm it shows an alert and ask you for installing all necessary packages.

remove space between paragraph and unordered list

This simple way worked fine for me:

<ul style="margin-top:-30px;">

How do I find all the files that were created today in Unix/Linux?

You can use find and ls to accomplish with this:

find . -type f -exec ls -l {} \; |  egrep "Aug 26";

It will find all files in this directory, display useful informations (-l) and filter the lines with some date you want... It may be a little bit slow, but still useful in some cases.

How to hide UINavigationBar 1px bottom line

Swift put this

UINavigationBar.appearance().setBackgroundImage(UIImage(), forBarPosition: .Any, barMetrics: .Default)
UINavigationBar.appearance().shadowImage = UIImage()


func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool

How do I use FileSystemObject in VBA?

Within Excel you need to set a reference to the VB script run-time library. The relevant file is usually located at \Windows\System32\scrrun.dll

  • To reference this file, load the Visual Basic Editor (ALT+F11)
  • Select Tools > References from the drop-down menu
  • A listbox of available references will be displayed
  • Tick the check-box next to 'Microsoft Scripting Runtime'
  • The full name and path of the scrrun.dll file will be displayed below the listbox
  • Click on the OK button.

This can also be done directly in the code if access to the VBA object model has been enabled.

Access can be enabled by ticking the check-box Trust access to the VBA project object model found at File > Options > Trust Center > Trust Center Settings > Macro Settings

VBA Macro settings

To add a reference:

Sub Add_Reference()

    Application.VBE.ActiveVBProject.References.AddFromFile "C:\Windows\System32\scrrun.dll"
'Add a reference

End Sub

To remove a reference:

Sub Remove_Reference()

Dim oReference As Object

    Set oReference = Application.VBE.ActiveVBProject.References.Item("Scripting")

    Application.VBE.ActiveVBProject.References.Remove oReference
'Remove a reference

End Sub

Bootstrap fixed header and footer with scrolling body-content area in fluid-container

Add the following css to disable the default scroll:

body {
    overflow: hidden;

And change the #content css to this to make the scroll only on content body:

#content {
    max-height: calc(100% - 120px);
    overflow-y: scroll;
    padding: 0px 10%;
    margin-top: 60px;

See fiddle here.


Actually, I'm not sure what was the issue you were facing, since it seems that your css is working. I have only added the HTML and the header css statement:

html {_x000D_
  height: 100%;_x000D_
html body {_x000D_
  height: 100%;_x000D_
  overflow: hidden;_x000D_
html body .container-fluid.body-content {_x000D_
  position: absolute;_x000D_
  top: 50px;_x000D_
  bottom: 30px;_x000D_
  right: 0;_x000D_
  left: 0;_x000D_
  overflow-y: auto;_x000D_
header {_x000D_
    position: absolute;_x000D_
    left: 0;_x000D_
    right: 0;_x000D_
    top: 0;_x000D_
    background-color: #4C4;_x000D_
    height: 50px;_x000D_
footer {_x000D_
    position: absolute;_x000D_
    left: 0;_x000D_
    right: 0;_x000D_
    bottom: 0;_x000D_
    background-color: #4C4;_x000D_
    height: 30px;_x000D_
<link href="" rel="stylesheet"/>_x000D_
<div class="container-fluid body-content">_x000D_
  Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>_x000D_
  Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>_x000D_
  Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>_x000D_
  Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>_x000D_
  Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>_x000D_

Multiple aggregations of the same column using pandas GroupBy.agg()

Would something like this work:

In [7]: df.groupby('dummy').returns.agg({'func1' : lambda x: x.sum(), 'func2' : lambda x:})
              func2     func1
1     -4.263768e-16 -0.188565

Can Windows' built-in ZIP compression be scripted?

Just for clarity: GZip is not an MS-only algorithm as suggested by Guy Starbuck in his comment from August. The GZipStream in System.IO.Compression uses the Deflate algorithm, just the same as the zlib library, and many other zip tools. That class is fully interoperable with unix utilities like gzip.

The GZipStream class is not scriptable from the commandline or VBScript, to produce ZIP files, so it alone would not be an answer the original poster's request.

The free DotNetZip library does read and produce zip files, and can be scripted from VBScript or Powershell. It also includes command-line tools to produce and read/extract zip files.

Here's some code for VBScript:

dim filename 
filename = "C:\temp\"

WScript.echo("Instantiating a ZipFile object...")
dim zip 
set zip = CreateObject("Ionic.Zip.ZipFile")

WScript.echo("using AES256 encryption...")
zip.Encryption = 3

WScript.echo("setting the password...")
zip.Password = "Very.Secret.Password!"

WScript.echo("adding a selection of files...")

WScript.echo("setting the save name...")
zip.Name = filename




Here's some code for Powershell:


$directoryToZip = "c:\\temp";
$zipfile =  new-object Ionic.Zip.ZipFile;
$e= $zipfile.AddEntry("Readme.txt", "This is a zipfile created from within powershell.")
$e= $zipfile.AddDirectory($directoryToZip, "home")

In a .bat or .cmd file, you can use the zipit.exe or unzip.exe tools. Eg:

zipit  -s "This is string content for an entry"  Readme.txt  src