Programs & Examples On #Pastrykit

How to 'foreach' a column in a DataTable using C#?

This should work:

DataTable dtTable;

MySQLProcessor.DTTable(mysqlCommand, out dtTable);

// On all tables' rows
foreach (DataRow dtRow in dtTable.Rows)
    // On all tables' columns
    foreach(DataColumn dc in dtTable.Columns)
      var field1 = dtRow[dc].ToString();

What is the benefit of zerofill in MySQL?

I know I'm late to the party but I find the zerofill is helpful for boolean representations of TINYINT(1). Null doesn't always mean False, sometimes you don't want it to. By zerofilling a tinyint, you're effectively converting those values to INT and removing any confusion ur application may have upon interaction. Your application can then treat those values in a manner similar to the primitive datatype True = Not(0)

How to publish a website made by Node.js to Github Pages?

It's very simple steps to push your node js application from local to GitHub.


  1. First create a new repository on GitHub
  2. Open Git CMD installed to your system (Install GitHub Desktop)
  3. Clone the repository to your system with the command: git clone repo-url
  4. Now copy all your application files to this cloned library if it's not there
  5. Get everything ready to commit: git add -A
  6. Commit the tracked changes and prepares them to be pushed to a remote repository: git commit -a -m "First Commit"
  7. Push the changes in your local repository to GitHub: git push origin master

'readline/readline.h' file not found

This command helped me on linux mint when i had exact same problem

gcc filename.c -L/usr/include -lreadline -o filename

You could use alias if you compile it many times Forexample:

alias compilefilename='gcc filename.c -L/usr/include -lreadline -o filename'

jQuery disable/enable submit button


let check = inp=> inp.nextElementSibling.disabled = !inp.value;
<input type="text" name="textField" oninput="check(this)"/>_x000D_
<input type="submit" value="send" disabled />

jquery change div text

Put the title in its own span.

<span id="dialog_title_span">'+dialog_title+'</span>
$('#dialog_title_span').text("new dialog title");

Import local function from a module housed in another directory with relative imports in Jupyter Notebook using Python 3

Researching this topic myself and having read the answers I recommend using the library since it provides a context manager for changing the current working directory.

You then have something like

import path
if path.Path('../lib').isdir():
    with path.Path('..'):
        import lib

Although, you might just omit the isdir statement.

Here I'll add print statements to make it easy to follow what's happening

import path
import pandas

if path.Path('../lib').isdir():
    with path.Path('..'):
        import lib

which outputs in this example (where lib is at /home/jovyan/shared/notebooks/by-team/data-vis/demos/lib):


Since the solution uses a context manager, you are guaranteed to go back to your previous working directory, no matter what state your kernel was in before the cell and no matter what exceptions are thrown by importing your library code.

How to find the maximum value in an array?

Iterate over the Array. First initialize the maximum value to the first element of the array and then for each element optimize it if the element under consideration is greater.

How to check if a key exists in Json Object and get its value

Please try this one..

JSONObject jsonObject= null;
try {
     jsonObject = new JSONObject("result........");
     String labelDataString=jsonObject.getString("LabelData");
     JSONObject labelDataJson= null;
     labelDataJson= new JSONObject(labelDataString);
       String video=labelDataJson.getString("video");
    } catch (JSONException e) {

Jackson: how to prevent field serialization

Starting with Jackson 2.6, a property can be marked as read- or write-only. It's simpler than hacking the annotations on both accessors and keeps all the information in one place:

public class User {
    @JsonProperty(access = JsonProperty.Access.WRITE_ONLY)
    private String password;

Eclipse "Server Locations" section disabled and need to change to use Tomcat installation

it worked for me after deleting and adding the server back.

Where do I find the definition of size_t?

size_t should be defined in your standard library's headers. In my experience, it usually is simply a typedef to unsigned int. The point, though, is that it doesn't have to be. Types like size_t allow the standard library vendor the freedom to change its underlying data types if appropriate for the platform. If you assume size_t is always unsigned int (via casting, etc), you could run into problems in the future if your vendor changes size_t to be e.g. a 64-bit type. It is dangerous to assume anything about this or any other library type for this reason.

Why is it that "No HTTP resource was found that matches the request URI" here?

Try this mate, you can chuck it in the body like so...

    public bool SampleCall([FromBody]JObject data)
        var firstName = data["firstName"].ToString();
        var lastName= data["lastName"].ToString();
        var email = data["email"].ToString();
        var obj= data["toLastName"].ToObject<SomeObject>();

        return _someService.DoYourBiz(firstName, lastName, email, obj);

How to read embedded resource text file

When you added the file to the resources, you should select its Access Modifiers as public than you can make something like following.

byte[] clistAsByteArray = Properties.Resources.CLIST01;

CLIST01 is the name of the embedded file.

Actually you can go to the resources.Designer.cs and see what is the name of the getter.

Turning multiple lines into one comma separated line

Perl one-liner:

perl -pe'chomp, s/$/,/ unless eof' file

or, if you want to be more cryptic:

perl '-peeof||chomp&&s/$/,/' file

How to set text size of textview dynamically for different screens

After long time stuck this issue, finally solved like this


create folder like this res/values/dimens.xml

<?xml version="1.0" encoding="utf-8"?>

  <dimen name="textsize">8sp</dimen>


Set position / size of UI element as percentage of screen size

Use the PercentRelativeLayout or PercentFrameLayout from the Percent Supoort Library


How to upgrade pip3?

The Problem

You use pip (the Python 2 one). Now you want to upgrade pip (the Python 3 one). After that, pip is the Python 3 one.

The solution

Use pip2 and pip3. This way it is explicit.

If you want to use pip, just check where it is (which pip) and change the link. For example:

$ which pip

$ pip --version
pip 9.0.1 from /usr/local/lib/python3.5/dist-packages (python 3.5)

$ which pip2

$ sudo rm /usr/local/bin/pip
$ sudo ln -s /usr/local/bin/pip2 /usr/local/bin/pip

$ pip --version
pip 9.0.1 from /usr/local/lib/python2.7/dist-packages (python 2.7)

Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on

I find the check-and-invoke code which needs to be littered within all methods related to forms to be way too verbose and unneeded. Here's a simple extension method which lets you do away with it completely:

public static class Extensions
    public static void Invoke<TControlType>(this TControlType control, Action<TControlType> del) 
        where TControlType : Control
            if (control.InvokeRequired)
                control.Invoke(new Action(() => del(control)));

And then you can simply do this:

textbox1.Invoke(t => t.Text = "A");

No more messing around - simple.

Adding value labels on a matplotlib bar chart

Based on a feature mentioned in this answer to another question I have found a very generally applicable solution for placing labels on a bar chart.

Other solutions unfortunately do not work in many cases, because the spacing between label and bar is either given in absolute units of the bars or is scaled by the height of the bar. The former only works for a narrow range of values and the latter gives inconsistent spacing within one plot. Neither works well with logarithmic axes.

The solution I propose works independent of scale (i.e. for small and large numbers) and even correctly places labels for negative values and with logarithmic scales because it uses the visual unit points for offsets.

I have added a negative number to showcase the correct placement of labels in such a case.

The value of the height of each bar is used as a label for it. Other labels can easily be used with Simon's for rect, label in zip(rects, labels) snippet.

import numpy as np
import pandas as pd
import matplotlib.pyplot as plt

# Bring some raw data.
frequencies = [6, -16, 75, 160, 244, 260, 145, 73, 16, 4, 1]

# In my original code I create a series and run on that,
# so for consistency I create a series from the list.
freq_series = pd.Series.from_array(frequencies)

x_labels = [108300.0, 110540.0, 112780.0, 115020.0, 117260.0, 119500.0,
            121740.0, 123980.0, 126220.0, 128460.0, 130700.0]

# Plot the figure.
plt.figure(figsize=(12, 8))
ax = freq_series.plot(kind='bar')
ax.set_title('Amount Frequency')
ax.set_xlabel('Amount ($)')

def add_value_labels(ax, spacing=5):
    """Add labels to the end of each bar in a bar chart.

        ax (matplotlib.axes.Axes): The matplotlib object containing the axes
            of the plot to annotate.
        spacing (int): The distance between the labels and the bars.

    # For each bar: Place a label
    for rect in ax.patches:
        # Get X and Y placement of label from rect.
        y_value = rect.get_height()
        x_value = rect.get_x() + rect.get_width() / 2

        # Number of points between bar and label. Change to your liking.
        space = spacing
        # Vertical alignment for positive values
        va = 'bottom'

        # If value of bar is negative: Place label below bar
        if y_value < 0:
            # Invert space to place label below
            space *= -1
            # Vertically align label at top
            va = 'top'

        # Use Y value as label and format number with one decimal place
        label = "{:.1f}".format(y_value)

        # Create annotation
            label,                      # Use `label` as label
            (x_value, y_value),         # Place label at end of the bar
            xytext=(0, space),          # Vertically shift label by `space`
            textcoords="offset points", # Interpret `xytext` as offset in points
            ha='center',                # Horizontally center label
            va=va)                      # Vertically align label differently for
                                        # positive and negative values.

# Call the function above. All the magic happens there.


Edit: I have extracted the relevant functionality in a function, as suggested by barnhillec.

This produces the following output:

Bar chart with automatically placed labels on each bar

And with logarithmic scale (and some adjustment to the input data to showcase logarithmic scaling), this is the result:

Bar chart with logarithmic scale with automatically placed labels on each bar

importing a CSV into phpmyadmin

Using the LOAD DATA INFILE SQL statement you can import the CSV file, but you can't update data. However, there is a trick you can use.

  • Create another temporary table to use for the import
  • Load onto this table from the CSC

    LOAD DATA LOCAL INFILE '/file.csv'
    INTO TABLE temp_table
    (field1, field2, field3); 
  • UPDATE the real table joining the table

    UPDATE maintable
    INNER JOIN temp_table A USING (field1)
    SET maintable.field1 = temp_table.field1

How do I programmatically "restart" an Android app?

Directly start the initial screen with FLAG_ACTIVITY_CLEAR_TASK and FLAG_ACTIVITY_NEW_TASK.

JQuery string contains check

If you are worrying about Case sensitive change the case and compare the string.

 if (stringvalue.toLocaleLowerCase().indexOf("mytexttocompare")!=-1)


AngularJS access scope from outside js function

It's been a long time since I asked this question, but here's an answer that doesn't require jquery:

function change() {
    var scope = angular.element(document.querySelector('#outside')).scope();
        scope.msg = 'Superhero';

How do I disable the resizable property of a textarea?

This can be done in HTML easily:

<textarea name="textinput" draggable="false"></textarea>

This works for me. The default value is true for the draggable attribute.

Config Error: This configuration section cannot be used at this path

Adding following key in registry solved my issue:


When I tried these steps I kept getting error:

  1. Search for "Turn windows features on or off"
  2. Check "Internet Information Services"
  3. Check "World Wide Web Services"
  4. Check "Application Development Features"
  5. Enable all items under this

Then i looked at event viewer and saw this error:Unable to install counter strings because the SYSTEM\CurrentControlSet\Services\ASP.NET_64\Performance key could not be opened or accessed. The first DWORD in the Data section contains the Win32 error code.

To fix the issue i manually created following entry in registry:


and followed these steps:

  1. Search for "Turn windows features on or off"
  2. Check "Internet Information Services"
  3. Check "World Wide Web Services"
  4. Check "Application Development Features"
  5. Enable all items under this

Importing project into Netbeans

If there is already a nbproject folder it means you can open it straight ahead without importing it as a project with existing sources (ctrl+shift+o) or (cmd+shift+o)

How to execute a Ruby script in Terminal?

For those not getting a solution for older answers, i simply put my file name as the very first line in my code.

like so


 puts "hello world"

What's the difference between select_related and prefetch_related in Django ORM?

Both methods achieve the same purpose, to forego unnecessary db queries. But they use different approaches for efficiency.

The only reason to use either of these methods is when a single large query is preferable to many small queries. Django uses the large query to create models in memory preemptively rather than performing on demand queries against the database.

select_related performs a join with each lookup, but extends the select to include the columns of all joined tables. However this approach has a caveat.

Joins have the potential to multiply the number of rows in a query. When you perform a join over a foreign key or one-to-one field, the number of rows won't increase. However, many-to-many joins do not have this guarantee. So, Django restricts select_related to relations that won't unexpectedly result in a massive join.

The "join in python" for prefetch_related is a little more alarming then it should be. It creates a separate query for each table to be joined. It filters each of these table with a WHERE IN clause, like:

SELECT "credential"."id",
FROM   "credential"
WHERE  "credential"."identity_id" IN
    (84706, 48746, 871441, 84713, 76492, 84621, 51472);

Rather than performing a single join with potentially too many rows, each table is split into a separate query.

HTML table with fixed headers?

Here is an improved answer to the one posted by Maximilian Hils.

This one works in Internet Explorer 11 with no flickering whatsoever:

var headerCells = tableWrap.querySelectorAll("thead td");
for (var i = 0; i < headerCells.length; i++) {
    var headerCell = headerCells[i]; = "silver";
var lastSTop = tableWrap.scrollTop;
tableWrap.addEventListener("scroll", function () {
    var stop = this.scrollTop;
    if (stop < lastSTop) {
        // Resetting the transform for the scrolling up to hide the headers
        for (var i = 0; i < headerCells.length; i++) {
            headerCells[i].style.transitionDelay = "0s";
            headerCells[i].style.transform = "";
    lastSTop = stop;
    var translate = "translate(0," + stop + "px)";
    for (var i = 0; i < headerCells.length; i++) {
        headerCells[i].style.transitionDelay = "0.25s";
        headerCells[i].style.transform = translate;

#1214 - The used table type doesn't support FULLTEXT indexes

*************Resolved - #1214 - The used table type doesn't support FULLTEXT indexes***************

Its Very Simple to resolve this issue. People are answering here in very difficult words which are not easily understandable by the people who are not technical.

So i am mentioning here steps in very simple words will resolve your issue.

1.) Open your .sql file with Notepad by right clicking on file>Edit Or Simply open a Notepad file and drag and drop the file on Notepad and the file will be opened. (Note: Please don't change the extention .sql of file as its still your sql database. Also to keep a copy of your sql file to save yourself from any mishappening)

2.) Click on Notepad Menu Edit > Replace (A Window will be pop us with Find What & Replace With Fields)

3.) In Find What Field Enter ENGINE=InnoDB & In Replace With Field Enter ENGINE=MyISAM

4.) Now Click on Replace All Button

5.) Click CTRL+S or File>Save

6.) Now Upload This File and I am Sure your issue will be resolved....

Uncaught TypeError: Cannot read property 'value' of undefined

You code looks like automatically generated from other code - you should check that html elements with id=i1 and i2 and name=username and password exists before processing them.

SQL Server Insert Example

Here are 4 ways to insert data into a table.

  1. Simple insertion when the table column sequence is known.

    INSERT INTO Table1 VALUES (1,2,...)

  2. Simple insertion into specified columns of the table.

    INSERT INTO Table1(col2,col4) VALUES (1,2)

  3. Bulk insertion when...

    1. You wish to insert every column of Table2 into Table1
    2. You know the column sequence of Table2
    3. You are certain that the column sequence of Table2 won't change while this statement is being used (perhaps you the statement will only be used once).

    INSERT INTO Table1 {Column sequence} SELECT * FROM Table2

  4. Bulk insertion of selected data into specified columns of Table2.


INSERT INTO Table1 (Column1,Column2 ....)
    SELECT Column1,Column2...
       FROM Table2

Error running android: Gradle project sync failed. Please fix your project and try again

This could be due to Android Studio version conflict of v3 and v4 especially when you import a project in android stdio v4 which was previously built in v3.

Here are the few things you need to do:

  • remove the .gradle and .idea folders from the main Application folder.
  • import the project in the android studio.
  • after the sync finished, it will ask you to update the android studio supported version.
  • click update.
  • done.

Could not find a version that satisfies the requirement tensorflow

Tensorflow seems to need special versions of tools and libs. Pip only takes care of python version.

To handle this in a professional way (means it save tremendos time for me and others) you have to set a special environment for each software like this.

An advanced tool for this is conda.

I installed Tensorflow with this commands:

sudo apt install python3

sudo update-alternatives --install /usr/bin/python python /usr/bin/python3 1

sudo apt install python3-pip

sudo apt-get install curl

curl >



source ~/.bashrc

  • installs its own phyton etc

nano .bashrc

  • maybe insert here your proxies etc.

conda create --name your_name python=3

conda activate your_name

conda install -c conda-forge tensorflow

  • check everything went well

python -c "import tensorflow as tf; tf.enable_eager_execution(); print(tf.reduce_sum(tf.random_normal([1000, 1000])))"

PS: some commands that may be helpful conda search tensorflow

uses virtualenv. Conda is more capable. Miniconda ist sufficient; the full conda is not necessary

Compiling a java program into an executable

I would use GCJ (GNU Compiler for Java) in your situation. It's an AOT (ahead of time) compiler for Java, much like GCC is for C. Instead of interpreting code, or generating intermediate java code to be run at a later time by the Java VM, it generates machine code.

GCJ is available on almost any Linux system through its respective package manager (if available). After installation, the GCJ compiler should be added to the path so that it can be invoked through the terminal. If you're using Windows, you can download and install GCJ through Cygwin or MinGW.

I would strongly recommend, however, that you rewrite your source for another language that is meant to be compiled, such as C++. Java is meant to be a portable, interpreted language. Compiling it to machine code is completely against what the language was developed for.

How to check if all list items have the same value and return it, or return an “otherValue” if they don’t?

A slight variation on the above simplified approach.

var result = yyy.Distinct().Count() == yyy.Count();

Are 'Arrow Functions' and 'Functions' equivalent / interchangeable?

To use arrow functions with, I made a helper function on the object prototype:

  // Using
  // @func = function() {use this here} or This => {use This here}
  using(func) {
    return, this);


  var obj = {f:3, a:2}
  .using(This => This.f + This.a) // 5


You don't NEED a helper. You could do:

var obj = {f:3, a:2}
(This => This.f + This.a).call(undefined, obj); // 5

How to show MessageBox on

Messagebox is for windows only. You have to use Javascript


What are the most common naming conventions in C?

I would recommend against mixing camel case and underscore separation (like you proposed for struct members). This is confusing. You'd think, hey I have get_length so I should probably have make_subset and then you find out it's actually makeSubset. Use the principle of least astonishment, and be consistent.

I do find CamelCase useful to type names, like structs, typedefs and enums. That's about all, though. For all the rest (function names, struct member names, etc.) I use underscore_separation.

Output (echo/print) everything from a PHP Array

You can use print_r to get human-readable output. But to display it as text we add "echo '';"

echo ''; print_r($row);

Simple working Example of in

Imports Newtonsoft.Json.Linq

Dim json As JObject = JObject.Parse(Me.TextBox1.Text)

Python socket receive - incoming packets always have a different size

The network is always unpredictable. TCP makes a lot of this random behavior go away for you. One wonderful thing TCP does: it guarantees that the bytes will arrive in the same order. But! It does not guarantee that they will arrive chopped up in the same way. You simply cannot assume that every send() from one end of the connection will result in exactly one recv() on the far end with exactly the same number of bytes.

When you say socket.recv(x), you're saying 'don't return until you've read x bytes from the socket'. This is called "blocking I/O": you will block (wait) until your request has been filled. If every message in your protocol was exactly 1024 bytes, calling socket.recv(1024) would work great. But it sounds like that's not true. If your messages are a fixed number of bytes, just pass that number in to socket.recv() and you're done.

But what if your messages can be of different lengths? The first thing you need to do: stop calling socket.recv() with an explicit number. Changing this:

data = self.request.recv(1024)

to this:

data = self.request.recv()

means recv() will always return whenever it gets new data.

But now you have a new problem: how do you know when the sender has sent you a complete message? The answer is: you don't. You're going to have to make the length of the message an explicit part of your protocol. Here's the best way: prefix every message with a length, either as a fixed-size integer (converted to network byte order using socket.ntohs() or socket.ntohl() please!) or as a string followed by some delimiter (like '123:'). This second approach often less efficient, but it's easier in Python.

Once you've added that to your protocol, you need to change your code to handle recv() returning arbitrary amounts of data at any time. Here's an example of how to do this. I tried writing it as pseudo-code, or with comments to tell you what to do, but it wasn't very clear. So I've written it explicitly using the length prefix as a string of digits terminated by a colon. Here you go:

length = None
buffer = ""
while True:
  data += self.request.recv()
  if not data:
  buffer += data
  while True:
    if length is None:
      if ':' not in buffer:
      # remove the length bytes from the front of buffer
      # leave any remaining bytes in the buffer!
      length_str, ignored, buffer = buffer.partition(':')
      length = int(length_str)

    if len(buffer) < length:
    # split off the full message from the remaining bytes
    # leave any remaining bytes in the buffer!
    message = buffer[:length]
    buffer = buffer[length:]
    length = None

Dialog to pick image from gallery or from camera

I think that's up to you to show that dialog for choosing. For Gallery you'll use that code, and for Camera try this.

c# - How to get sum of the values from List?

Use Sum()

 List<string> foo = new List<string>();

 Console.Write(foo.Sum(x => Convert.ToInt32(x)));



How to Cast Objects in PHP

PHP provides a very simple way of doing this by using:

(object) ['id'=>1,'name'=>'cat']

In your case you try this:

$dog = json_encode($dog);

$cat = (object) json_decode($dog)

More optimize method is:

$dog = (array)$dog;
$dog['newfield'] = 'xyz';
$dog = (object)$dog;

Round to 5 (or other number) in Python

No one actually wrote this yet I guess but you can do:

round(12, -1) --> 10
round(18, -1) --> 20

Node.js project naming conventions for files & folders

Node.js doesn't enforce any file naming conventions (except index.js). And the Javascript language in general doesn't either. You can find dozens of threads here which suggest camelCase, hyphens and underscores, any of which work perfectly well. So its up to you. Choose one and stick with it.

Maximum packet size for a TCP connection

It seems most web sites out on the internet use 1460 bytes for the value of MTU. Sometimes it's 1452 and if you are on a VPN it will drop even more for the IPSec headers.

The default window size varies quite a bit up to a max of 65535 bytes. I use to look at my own source IP values and to check what other Internet vendors are using.

Import JavaScript file and call functions using webpack, ES6, ReactJS

Named exports:

Let's say you create a file called utils.js, with utility functions that you want to make available for other modules (e.g. a React component). Then you would make each function a named export:

export function add(x, y) {
  return x + y

export function mutiply(x, y) {
  return x * y

Assuming that utils.js is located in the same directory as your React component, you can use its exports like this:

import { add, multiply } from './utils.js';
add(2, 3) // Can be called wherever in your component, and would return 5.

Or if you prefer, place the entire module's contents under a common namespace:

import * as utils from './utils.js'; 

Default exports:

If you on the other hand have a module that only does one thing (could be a React class, a normal function, a constant, or anything else) and want to make that thing available to others, you can use a default export. Let's say we have a file log.js, with only one function that logs out whatever argument it's called with:

export default function log(message) {

This can now be used like this:

import log from './log.js';
log('test') // Would print 'test' in the console.

You don't have to call it log when you import it, you could actually call it whatever you want:

import logToConsole from './log.js';
logToConsole('test') // Would also print 'test' in the console.


A module can have both a default export (max 1), and named exports (imported either one by one, or using * with an alias). React actually has this, consider:

import React, { Component, PropTypes } from 'react';

Databound drop down list - initial value

To select a value from the dropdown use the index like this:

if we have the

<asp:DropDownList ID="DropDownList1" runat="server" AppendDataBoundItems="true"></asp:DropDownList>

you would use :


this would return the value for the selected index.

How to check for file lock?

When I faced with a similar problem, I finished with the following code:

public bool IsFileLocked(string filePath)
        using (File.Open(filePath, FileMode.Open)){}
    catch (IOException e)
        var errorCode = Marshal.GetHRForException(e) & ((1 << 16) - 1);

        return errorCode == 32 || errorCode == 33;

    return false;

LaTeX "\indent" creating paragraph indentation / tabbing package requirement?

The first line of a paragraph is indented by default, thus whether or not you have \indent there won't make a difference. \indent and \noindent can be used to override default behavior. You can see this by replacing your line with the following:

Now we are engaged in a great civil war.\\
\indent this is indented\\
this isn't indented

\noindent override default indentation (not indented)\\

Create dataframe from a matrix

I've found the following "cheat" to work very neatly and error-free

> dimnames <- list(time=c(0, 0.5, 1), name=c("C_0", "C_1"))
> mat <- matrix(data, ncol=2, nrow=3, dimnames=dimnames)
> head(mat, 2) #this returns the number of rows indicated in a data frame format
> df <- data.frame(head(mat, 2)) #"data.frame" might not be necessary

Et voila!

Difference between and logger.debug

I suggest you look at the article called "Short Introduction to log4j". It contains a short explanation of log levels and demonstrates how they can be used in practice. The basic idea of log levels is that you want to be able to configure how much detail the logs contain depending on the situation. For example, if you are trying to troubleshoot an issue, you would want the logs to be very verbose. In production, you might only want to see warnings and errors.

The log level for each component of your system is usually controlled through a parameter in a configuration file, so it's easy to change. Your code would contain various logging statements with different levels. When responding to an Exception, you might call Logger.error. If you want to print the value of a variable at any given point, you might call Logger.debug. This combination of a configurable logging level and logging statements within your program allow you full control over how your application will log its activity.

In the case of log4j at least, the ordering of log levels is:


Here is a short example from that article demonstrating how log levels work.

   // get a logger instance named ""
   Logger logger = Logger.getLogger("");

   // Now set its level. Normally you do not need to set the
   // level of a logger programmatically. This is usually done
   // in configuration files.

   Logger barlogger = Logger.getLogger("");

   // This request is enabled, because WARN >= INFO.
   logger.warn("Low fuel level.");

   // This request is disabled, because DEBUG < INFO.
   logger.debug("Starting search for nearest gas station.");

   // The logger instance barlogger, named "",
   // will inherit its level from the logger named
   // "" Thus, the following request is enabled
   // because INFO >= INFO."Located nearest gas station.");

   // This request is disabled, because DEBUG < INFO.
   barlogger.debug("Exiting gas station search");

How to add checkboxes to JTABLE swing

1) JTable knows JCheckbox with built-in Boolean TableCellRenderers and TableCellEditor by default, then there is contraproductive declare something about that,

2) AbstractTableModel should be useful, where is in the JTable required to reduce/restrict/change nested and inherits methods by default implemented in the DefaultTableModel,

3) consider using DefaultTableModel, (if you are not sure about how to works) instead of AbstractTableModel,


could be generated from simple code:

import javax.swing.*;
import javax.swing.table.*;

public class TableCheckBox extends JFrame {

    private static final long serialVersionUID = 1L;
    private JTable table;

    public TableCheckBox() {
        Object[] columnNames = {"Type", "Company", "Shares", "Price", "Boolean"};
        Object[][] data = {
            {"Buy", "IBM", new Integer(1000), new Double(80.50), false},
            {"Sell", "MicroSoft", new Integer(2000), new Double(6.25), true},
            {"Sell", "Apple", new Integer(3000), new Double(7.35), true},
            {"Buy", "Nortel", new Integer(4000), new Double(20.00), false}
        DefaultTableModel model = new DefaultTableModel(data, columnNames);
        table = new JTable(model) {

            private static final long serialVersionUID = 1L;

            public Class getColumnClass(int column) {
            return getValueAt(0, column).getClass();
            public Class getColumnClass(int column) {
                switch (column) {
                    case 0:
                        return String.class;
                    case 1:
                        return String.class;
                    case 2:
                        return Integer.class;
                    case 3:
                        return Double.class;
                        return Boolean.class;
        JScrollPane scrollPane = new JScrollPane(table);

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            public void run() {
                TableCheckBox frame = new TableCheckBox();
                frame.setLocation(150, 150);

How to negate a method reference predicate

I'm planning to static import the following to allow for the method reference to be used inline:

public static <T> Predicate<T> not(Predicate<T> t) {
    return t.negate();


Stream<String> s = ...;
long nonEmptyStrings = s.filter(not(String::isEmpty)).count();

Update: Starting from Java-11, the JDK offers a similar solution built-in as well.

What is the 'pythonic' equivalent to the 'fold' function from functional programming?

I believe some of the respondents of this question have missed the broader implication of the fold function as an abstract tool. Yes, sum can do the same thing for a list of integers, but this is a trivial case. fold is more generic. It is useful when you have a sequence of data structures of varying shape and want to cleanly express an aggregation. So instead of having to build up a for loop with an aggregate variable and manually recompute it each time, a fold function (or the Python version, which reduce appears to correspond to) allows the programmer to express the intent of the aggregation much more plainly by simply providing two things:

  • A default starting or "seed" value for the aggregation.
  • A function that takes the current value of the aggregation (starting with the "seed") and the next element in the list, and returns the next aggregation value.

How to do INSERT into a table records extracted from another table

Do you want to insert extraction in an existing table?

If it does not matter then you can try the below query:

SELECT LongIntColumn1, Avg(CurrencyColumn) as CurrencyColumn1 INTO T1 FROM Table1 
GROUP BY LongIntColumn1);

It will create a new table -> T1 with the extracted information

Html encode in PHP

Try this:

    $str = "This is some <b>bold</b> text.";
    echo htmlspecialchars($str);

How to calculate date difference in JavaScript?

function DateDiff(date1, date2) {
    date1.setMinutes(0, 0, 0);
    date2.setMinutes(0, 0, 0);
    var datediff = Math.abs(date1.getTime() - date2.getTime()); // difference 
    return parseInt(datediff / (24 * 60 * 60 * 1000), 10); //Convert values days and return value      

Chart.js v2 hide dataset labels

You can also put the tooltip onto one line by removing the "title":

this.chart = new Chart(ctx, {
    type: this.props.horizontal ? 'horizontalBar' : 'bar',
    options: {
        legend: {
            display: false,
        tooltips: {
            callbacks: {
                label: tooltipItem => `${tooltipItem.yLabel}: ${tooltipItem.xLabel}`, 
                title: () => null,

enter image description here

How do I ignore a directory with SVN?

Important to mention:

On the commandline you can't use

svn add *

This will also add the ignored files, because the command line expands * and therefore svn add believes that you want all files to be added. Therefore use this instead:

svn add --force .

How to get the last element of an array in Ruby?

One other way, using the splat operator:

*a, last = [1, 3, 4, 5]

a: [1, 3, 4]
last: 5

how to change onclick event with jquery?

Updating this post (2015) : unbind/bind should not be used anymore with jQuery 1.7+. Use instead the function off(). Example :

    //Other code etc.

Be sure that you call a non-parameter function in .click, otherwise it will be ignored.

Why is String immutable in Java?

If HELLO is your String then you can't change HELLO to HILLO. This property is called immutability property.

You can have multiple pointer String variable to point HELLO String.

But if HELLO is char Array then you can change HELLO to HILLO. Eg,

char[] charArr = 'HELLO';
char[1] = 'I'; //you can do this


Programming languages have immutable data variables so that it can be used as keys in key, value pair. String variables are used as keys/indices, so they are immutable.

What is the difference between MVC and MVVM?

The other answers might not be easy to understand for one who is not much familiar with the subject of architectural patterns. Someone who is new to app architecture might want to know how its choice can affect her app in practice and what all the fuss is about in communities.

Trying to shed some light on the above, I made up this screenplay involving MVVM, MVP and MVC. The story begins by a user clicking on the ‘FIND’ button in a movie search app… :

User: Click …

View: Who’s that? [MVVM|MVP|MVC]

User: I just clicked on the search button …

View: Ok, hold on a sec … . [MVVM|MVP|MVC]

( View calling the ViewModel|Presenter|Controller … ) [MVVM|MVP|MVC]

View: Hey ViewModel|Presenter|Controller, a User has just clicked on the search button, what shall I do? [MVVM|MVP|MVC]

ViewModel|Presenter|Controller: Hey View, is there any search term on that page? [MVVM|MVP|MVC]

View: Yes,… here it is … “piano” [MVVM|MVP|MVC]

—— This is the most important difference between MVVM AND MVP|MVC ———

Presenter: Thanks View,… meanwhile I’m looking up the search term on the Model, please show him/her a progress bar [MVP|MVC]

( Presenter|Controller is calling the Model … ) [MVP|MVC]

ViewController: Thanks, I’ll be looking up the search term on the Model but will not update you directly. Instead, I will trigger events to searchResultsListObservable if there is any result. So you had better observe on that. [MVVM]

(While observing on any trigger in searchResultsListObservable, the View thinks it should show some progress bar to the user, since ViewModel would not talk to it on that)


ViewModel|Presenter|Controller: Hey Model, Do you have any match for this search term?: “piano” [MVVM|MVP|MVC]

Model: Hey ViewModel|Presenter|Controller, let me check … [MVVM|MVP|MVC]

( Model is making a query to the movie database … ) [MVVM|MVP|MVC]

( After a while … )

———— This is the diverging point between MVVM, MVP and MVC ————–

Model: I found a list for you, ViewModel|Presenter, here it is in JSON “[{“name”:”Piano Teacher”,”year”:2001},{“name”:”Piano”,”year”:1993}]” [MVVM|MVP]

Model: There is some result available, Controller. I have created a field variable in my instance and filled it with the result. It’s name is “searchResultsList” [MVC]

(Presenter|Controller thanks Model and gets back to the View) [MVP|MVC]

Presenter: Thanks for waiting View, I found a list of matching results for you and arranged them in a presentable format: [“Piano Teacher 2001",”Piano 1993”]. Also please hide the progress bar now [MVP]

Controller: Thanks for waiting View, I have asked Model about your search query. It says it has found a list of matching results and stored them in a variable named “searchResultsList” inside its instance. You can get it from there. Also please hide the progress bar now [MVC]

ViewModel: Any observer on searchResultsListObservable be notified that there is this new list in presentable format: [“Piano Teacher 2001",”Piano 1993”].[MVVM]

View: Thank you very much Presenter [MVP]

View: Thank you “Controller” [MVC] (Now the View is questioning itself: How should I present the results I get from the Model to the user? Should the production year of the movie come first or last…?)

View: Oh, there is a new trigger in searchResultsListObservable … , good, there is a presentable list, now I only have to show it in a list. I should also hide the progress bar now that I have the result. [MVVM]

In case you are interested, I have written a series of articles here, comparing MVVM, MVP and MVC by implementing a movie search android app.

What's the simplest way to print a Java array?

Starting with Java 8, one could also take advantage of the join() method provided by the String class to print out array elements, without the brackets, and separated by a delimiter of choice (which is the space character for the example shown below):

String[] greeting = {"Hey", "there", "amigo!"};
String delimiter = " ";
String.join(delimiter, greeting) 

The output will be "Hey there amigo!".

How to find all occurrences of an element in a list

You can use a list comprehension:

indices = [i for i, x in enumerate(my_list) if x == "whatever"]

adding to window.onload event?

There are basically two ways

  1. store the previous value of window.onload so your code can call a previous handler if present before or after your code executes

  2. using the addEventListener approach (that of course Microsoft doesn't like and requires you to use another different name).

The second method will give you a bit more safety if another script wants to use window.onload and does it without thinking to cooperation but the main assumption for Javascript is that all the scripts will cooperate like you are trying to do.

Note that a bad script that is not designed to work with other unknown scripts will be always able to break a page for example by messing with prototypes, by contaminating the global namespace or by damaging the dom.

Regex for quoted string with escaping quotes


Alternating the \" and the . passes over escaped quotes while the lazy quantifier *? ensures that you don't go past the end of the quoted string. Works with .NET Framework RE classes

Selecting a row in DataGridView programmatically

Not tested, but I think you can do the following:

dataGrid.Rows[index].Selected = true;

or you could do the following (but again: not tested):

foreach(DataGridViewRow row in dataGrid.Rows)
       row.Selected = true;

Automatic exit from Bash shell script on error

One point missed in the existing answers is show how to inherit the error traps. The bash shell provides one such option for that using set


If set, any trap on ERR is inherited by shell functions, command substitutions, and commands executed in a subshell environment. The ERR trap is normally not inherited in such cases.

Adam Rosenfield's answer recommendation to use set -e is right in certain cases but it has its own potential pitfalls. See GreyCat's BashFAQ - 105 - Why doesn't set -e (or set -o errexit, or trap ERR) do what I expected?

According to the manual, set -e exits

if a simple commandexits with a non-zero status. The shell does not exit if the command that fails is part of the command list immediately following a while or until keyword, part of the test in a if statement, part of an && or || list except the command following the final && or ||, any command in a pipeline but the last, or if the command's return value is being inverted via !".

which means, set -e does not work under the following simple cases (detailed explanations can be found on the wiki)

  1. Using the arithmetic operator let or $((..)) ( bash 4.1 onwards) to increment a variable value as

    #!/usr/bin/env bash
    set -e
    let i++                   # or ((i++)) on bash 4.1 or later
    echo "i is $i" 
  2. If the offending command is not part of the last command executed via && or ||. For e.g. the below trap wouldn't fire when its expected to

    #!/usr/bin/env bash
    set -e
    test -d nosuchdir && echo no dir
    echo survived
  3. When used incorrectly in an if statement as, the exit code of the if statement is the exit code of the last executed command. In the example below the last executed command was echo which wouldn't fire the trap, even though the test -d failed

    #!/usr/bin/env bash
    set -e
    f() { if test -d nosuchdir; then echo no dir; fi; }
    echo survived
  4. When used with command-substitution, they are ignored, unless inherit_errexit is set with bash 4.4

    #!/usr/bin/env bash
    set -e
    foo=$(expr 1-1; true)
    echo survived
  5. when you use commands that look like assignments but aren't, such as export, declare, typeset or local. Here the function call to f will not exit as local has swept the error code that was set previously.

    set -e
    f() { local var=$(somecommand that fails); }        
    g() { local var; var=$(somecommand that fails); }
  6. When used in a pipeline, and the offending command is not part of the last command. For e.g. the below command would still go through. One options is to enable pipefail by returning the exit code of the first failed process:

    set -e
    somecommand that fails | cat -
    echo survived

The ideal recommendation is to not use set -e and implement an own version of error checking instead. More information on implementing custom error handling on one of my answers to Raise error in a Bash script

How to increase font size in a plot in R?

You want something like the cex=1.5 argument to scale fonts 150 percent. But do see help(par) as there are also cex.lab, cex.axis, ...

SQL Server dynamic PIVOT query?

Dynamic SQL PIVOT:

create table temp
    date datetime,
    category varchar(3),
    amount money

insert into temp values ('1/1/2012', 'ABC', 1000.00)
insert into temp values ('2/1/2012', 'DEF', 500.00)
insert into temp values ('2/1/2012', 'GHI', 800.00)
insert into temp values ('2/10/2012', 'DEF', 700.00)
insert into temp values ('3/1/2012', 'ABC', 1100.00)

    @query  AS NVARCHAR(MAX);

SET @cols = STUFF((SELECT distinct ',' + QUOTENAME(c.category) 
            FROM temp c
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 

set @query = 'SELECT date, ' + @cols + ' from 
                select date
                    , amount
                    , category
                from temp
           ) x
                for category in (' + @cols + ')
            ) p '


drop table temp


Date                        ABC         DEF    GHI
2012-01-01 00:00:00.000     1000.00     NULL    NULL
2012-02-01 00:00:00.000     NULL        500.00  800.00
2012-02-10 00:00:00.000     NULL        700.00  NULL
2012-03-01 00:00:00.000     1100.00     NULL    NULL

How to check String in response body with mockMvc

String body = mockMvc.perform(bla... bla).andReturn().getResolvedException().getMessage()

This should give you the body of the response. "Username already taken" in your case.

C# Clear Session

In ASP.NET, when should I use Session.Clear() rather than Session.Abandon()?

Session.Abandon() destroys the session and the Session_OnEnd event is triggered.

Session.Clear() just removes all values (content) from the Object. The session with the same key is still alive.

So, if you use Session.Abandon(), you lose that specific session and the user will get a new session key. You could use it for example when the user logs out.

Use Session.Clear(), if you want that the user remaining in the same session (if you don't want him to relogin for example) and reset all his session specific data.

What is the difference between Session.Abandon() and Session.Clear()

Clear - Removes all keys and values from the session-state collection.

Abandon - removes all the objects stored in a Session. If you do not call the Abandon method explicitly, the server removes these objects and destroys the session when the session times out. It also raises events like Session_End.

Session.Clear can be compared to removing all books from the shelf, while Session.Abandon is more like throwing away the whole shelf.


Generally, in most cases you need to use Session.Clear. You can use Session.Abandon if you are sure the user is going to leave your site.

So back to the differences:

  • Abandon raises Session_End request.
  • Clear removes items immediately, Abandon does not.
  • Abandon releases the SessionState object and its items so it can garbage collected.
  • Clear keeps SessionState and resources associated with it.

Session.Clear() or Session.Abandon() ?

You use Session.Clear() when you don't want to end the session but rather just clear all the keys in the session and reinitialize the session.

Session.Clear() will not cause the Session_End eventhandler in your Global.asax file to execute.

But on the other hand Session.Abandon() will remove the session altogether and will execute Session_End eventhandler.

Session.Clear() is like removing books from the bookshelf

Session.Abandon() is like throwing the bookshelf itself.


I check on some sessions if not equal null in the page load. if one of them equal null i wanna to clear all the sessions and redirect to the login page?


If you want the user to login again, use Session.Abandon.

MIT vs GPL license

It seems to me that the chief difference between the MIT license and GPL is that the MIT doesn't require modifications be open sourced whereas the GPL does.

True - in general. You don't have to open-source your changes if you're using GPL. You could modify it and use it for your own purpose as long as you're not distributing it. BUT... if you DO distribute it, then your entire project that is using the GPL code also becomes GPL automatically. Which means, it must be open-sourced, and the recipient gets all the same rights as you - meaning, they can turn around and distribute it, modify it, sell it, etc. And that would include your proprietary code which would then no longer be proprietary - it becomes open source.

The difference with MIT is that even if you actually distribute your proprietary code that is using the MIT licensed code, you do not have to make the code open source. You can distribute it as a closed app where the code is encrypted or is a binary. Including the MIT-licensed code can be encrypted, as long as it carries the MIT license notice.

is the GPL is more restrictive than the MIT license?

Yes, very much so.

SQL Server: Invalid Column Name

I just tried. If you execute the statement to generate your local table, the tool will accept that this column name exists. Just mark the table generation statement in your editor window and click execute.

Why is my Button text forced to ALL CAPS on Lollipop?

I don't have idea why it is happening but there 3 trivial attempts to make:

  1. Use android:textAllCaps="false" in your layout-v21

  2. Programmatically change the transformation method of the button. mButton.setTransformationMethod(null);

  3. Check your style for Allcaps

Note: public void setAllCaps(boolean allCaps), android:textAllCaps are available from API version 14.

Visual Studio Code how to resolve merge conflicts with git?

  1. Click "Source Control" button on left.
  2. See MERGE CHANGES in sidebar.
  3. Those files have merge conflicts.

VS Code > Source Control > Merge Changes (Example)

Google Maps Android API v2 - Interactive InfoWindow (like in original android google maps)

I see that this question is already old but still...

We made a sipmle library at our company for achieving what is desired - An interactive info window with views and everything. You can check it out on github.

I hope it helps :)

Remove duplicates from dataframe, based on two columns A,B, keeping row with max value in another column C

You can do it with drop_duplicates as you wanted

# initialisation
d = pd.DataFrame({'A' : [1,1,2,3,3], 'B' : [2,2,7,4,4],  'C' : [1,4,1,0,8]})

d = d.sort_values("C", ascending=False)
d = d.drop_duplicates(["A","B"])

If it's important to get the same order

d = d.sort_index()

Configuration with name 'default' not found. Android Studio

I also faced the same problem and the problem was that the libraries were missing in some of the following files.

settings.gradle, app/build.gradle, package.json,

Suppose the library is react-native-vector-icons then it should be mentioned in following files;

In app/build.gradle file under dependencies section add:

compile project(':react-native-vector-icons')

In settings.gradle file under android folder, add the following:

include ':react-native-vector-icons' project(':react-native-vector-icons').projectDir = new File(rootProject.projectDir, '../node_modules/react-native-vector-icons/android')

In, add the following:

Import the dependency: import com.oblador.vectoricons.VectorIconsPackage;

and then add: new VectorIconsPackage() in getPackages() method.

Java/ JUnit - AssertTrue vs AssertFalse

I think it's just for your convenience (and the readers of your code)

Your code, and your unit tests should be ideally self documenting which this API helps with,

Think abt what is more clear to read:

AssertTrue(!(a > 3));


AssertFalse(a > 3);

When you open your tests after xx months when your tests suddenly fail, it would take you much less time to understand what went wrong in the second case (my opinion). If you disagree, you can always stick with AssertTrue for all cases :)

System.Data.OracleClient requires Oracle client software version 8.1.7

The author of this post (now deleted post) suggests checking your C:\Windows\System32 folder to make sure that the oci.dll exists there. Copying in the file from the Oracle home directory solved this problem for me.

How to get source code of a Windows executable?

For Any *.Exe file written in any language .You can view the source code with hiew (otherwise Hackers view). You can download it at It will be the demo version but still can view the code.

After this follow these steps:

  1. Press alt+f2 to navigate to the file.

  2. Press enter to see its assembly / c++ code.

PHP: How do you determine every Nth iteration of a loop?

Going off of @Powerlord's answer,

"There is one catch: 0 % 3 is equal to 0. This could result in unexpected results if your counter starts at 0."

You can still start your counter at 0 (arrays, querys), but offset it

if (($counter + 1) % 3 == 0) {
  echo 'image file';

Bootstrap throws Uncaught Error: Bootstrap's JavaScript requires jQuery

If you're in a Browser-Only environment, use SridharR's solution.

If you're in a Node/CommonJS + Browser environment (e.g. electron, node-webkit, etc..); the reason for this error is that jQuery's export logic first checks for module, not window:

if (typeof module === "object" && typeof module.exports === "object") {
    // CommonJS/Node
} else {
    // window

Note that it exports itself via module.exports in this case; so jQuery and $ are not assigned to window.

So to resolve this, instead of <script src="path/to/jquery.js"></script>;

Simply assign it yourself by a require statement:

    window.jQuery = window.$ = require('jquery');

NOTE: If your electron app does not need nodeIntegration, set it to false so you won't need this workaround.

Why am I getting this redefinition of class error?

If you are having issues with templates or you are calling the class from another .cpp file

try using '#pragma once' in your header file.

What is logits, softmax and softmax_cross_entropy_with_logits?

Tensorflow 2.0 Compatible Answer: The explanations of dga and stackoverflowuser2010 are very detailed about Logits and the related Functions.

All those functions, when used in Tensorflow 1.x will work fine, but if you migrate your code from 1.x (1.14, 1.15, etc) to 2.x (2.0, 2.1, etc..), using those functions result in error.

Hence, specifying the 2.0 Compatible Calls for all the functions, we discussed above, if we migrate from 1.x to 2.x, for the benefit of the community.

Functions in 1.x:

  1. tf.nn.softmax
  2. tf.nn.softmax_cross_entropy_with_logits
  3. tf.nn.sparse_softmax_cross_entropy_with_logits

Respective Functions when Migrated from 1.x to 2.x:

  1. tf.compat.v2.nn.softmax
  2. tf.compat.v2.nn.softmax_cross_entropy_with_logits
  3. tf.compat.v2.nn.sparse_softmax_cross_entropy_with_logits

For more information about migration from 1.x to 2.x, please refer this Migration Guide.

What's the better (cleaner) way to ignore output in PowerShell?

I would consider using something like:

function GetList
  . {
     $a = new-object Collections.ArrayList
     $a.Add('next 5')
  } | Out-Null
$x = GetList

Output from $a.Add is not returned -- that holds for all $a.Add method calls. Otherwise you would need to prepend [void] before each the call.

In simple cases I would go with [void]$a.Add because it is quite clear that output will not be used and is discarded.

Can a CSV file have a comment?

No, CSV doesn't specify any way of tagging comments - they will just be loaded by programs like Excel as additional cells containing text.

The closest you can manage (with CSV being imported into a specific application such as Excel) is to define a special way of tagging comments that Excel will ignore. For Excel, you can "hide" the comment (to a limited degree) by embedding it into a formula. For example, try importing the following csv file into Excel:

=N("This is a comment and will appear as a simple zero value in excel")
John, Doe, 24

You still end up with a cell in the spreadsheet that displays the number 0, but the comment is hidden.

Alternatively, you can hide the text by simply padding it out with spaces so that it isn't displayed in the visible part of cell:

                              This is a sort-of hidden comment!,
John, Doe, 24

Note that you need to follow the comment text with a comma so that Excel fills the following cell and thus hides any part of the text that doesn't fit in the cell.

Nasty hacks, which will only work with Excel, but they may suffice to make your output look a little bit tidier after importing.

How to add screenshot to READMEs in github repository?

If you use Markdown (

Provided that you have the image in your repo, you can use a relative URL:

![Alt text](/relative/path/to/img.jpg?raw=true "Optional Title")

If you need to embed an image that's hosted elsewhere, you can use a full URL

![Alt text](http://full/path/to/img.jpg "Optional title")

GitHub recommend that you use relative links with the ?raw=true parameter to ensure forked repos point correctly.

The raw=true parameter is there in order to ensure the image you link to, will be rendered as is. That means that only the image will be linked to, not the whole GitHub interface for that respective file. See this comment for more details.

Check out an example:

If you use SVGs then you'll need to set the sanitize attribute to true as well: ?raw=true&sanitize=true. (Thanks @EliSherer)

Also, the documentation on relative links in README files:

And of course the markdown docs:

Additionally, if you create a new branch screenshots to store the images you can avoid them being in the master working tree

You can then embed them using:

![Alt text](/../<branch name>/path/to/image.png?raw=true "Optional Title")

make: *** No rule to make target `all'. Stop

Your makefile should ideally be named makefile, not make. Note that you can call your makefile anything you like, but as you found, you then need the -f option with make to specify the name of the makefile. Using the default name of makefile just makes life easier.

failed to resolve and

Failed to find:

The "I literally tried everything else" answer:

This problem will also occur if you don't have an upto date Android Support Library and Android Support Repository. Just install using the SDK manager.

angularjs: allows only numbers to be typed into a text box

 <input type="text" ng-keypress="checkNumeric($event)"/>
 //inside controller
 $ = false
 $scope.checkNumeric = function($event){
 if(String.fromCharCode($event.keyCode) == "." && !${
    $ = true
 else if( isNaN(String.fromCharCode($event.keyCode))){

Convert List to Pandas Dataframe Column

For Converting a List into Pandas Core Data Frame, we need to use DataFrame Method from pandas Package.

There are Different Ways to Perform the Above Operation.

import pandas as pd

  1. pd.DataFrame({'Column_Name':Column_Data})
  • Column_Name : String
  • Column_Data : List Form
  1. Data = pd.DataFrame(Column_Data)

    Data.columns = ['Column_Name']

So, for the above mentioned issue, the code snippet is

import pandas as pd

Content = ['Thanks You',
           'Its fine no problem',
           'Are you sure']

Data = pd.DataFrame({'Text': Content})

Pandas: Appending a row to a dataframe and specify its index label

There is another solution. The next code is bad (although I think pandas needs this feature):

import pandas as pd

# empty dataframe
a = pd.DataFrame()
a.loc[0] = {'first': 111, 'second': 222}

But the next code runs fine:

import pandas as pd

# empty dataframe
a = pd.DataFrame()
a = a.append(pd.Series({'first': 111, 'second': 222}, name=0))

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


will select the whole block.

Play with also:

v}, vp, vs, etc.

See help:

:help text-objects

which lists the different ways to select letters, words, sentences, paragraphs, blocks, and so on.

gulp command not found - error after installing gulp

  1. npm install -g gulp
  2. Add environment variables in windows: enter image description here

How to set layout_gravity programmatically?

FloatingActionButton sendFab = new FloatingActionButton(this);
    FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
    layoutParams.setMargins(32, 32, 32, 32);
    layoutParams.gravity = Gravity.END|Gravity.BOTTOM;

Converting from a string to boolean in Python?

I use

# function
def toBool(x):
    return x in ("True","true",True)

# test cases
[[x, toBool(x)] for x in [True,"True","true",False,"False","false",None,1,0,-1,123]]
[[True, True],
 ['True', True],
 ['true', True],
 [False, False],
 ['False', False],
 ['false', False],
 [None, False],
 [1, True],
 [0, False],
 [-1, False],
 [123, False]]

Posting parameters to a url using the POST method without using a form


  { key1: "value1", key2: "value2" },
  function(data) {
    alert("Response: " + data);

How to declare Global Variables in Excel VBA to be visible across the Workbook

Your question is: are these not modules capable of declaring variables at global scope?

Answer: YES, they are "capable"

The only point is that references to global variables in ThisWorkbook or a Sheet module have to be fully qualified (i.e., referred to as ThisWorkbook.Global1, e.g.) References to global variables in a standard module have to be fully qualified only in case of ambiguity (e.g., if there is more than one standard module defining a variable with name Global1, and you mean to use it in a third module).

For instance, place in Sheet1 code

Public glob_sh1 As String

Sub test_sh1()
    Debug.Print (glob_mod)
    Debug.Print (ThisWorkbook.glob_this)
    Debug.Print (Sheet1.glob_sh1)
End Sub

place in ThisWorkbook code

Public glob_this As String

Sub test_this()
    Debug.Print (glob_mod)
    Debug.Print (ThisWorkbook.glob_this)
    Debug.Print (Sheet1.glob_sh1)
End Sub

and in a Standard Module code

Public glob_mod As String

Sub test_mod()
    glob_mod = "glob_mod"
    ThisWorkbook.glob_this = "glob_this"
    Sheet1.glob_sh1 = "glob_sh1"
    Debug.Print (glob_mod)
    Debug.Print (ThisWorkbook.glob_this)
    Debug.Print (Sheet1.glob_sh1)
End Sub

All three subs work fine.

PS1: This answer is based essentially on info from here. It is much worth reading (from the great Chip Pearson).

PS2: Your line Debug.Print ("Hello") will give you the compile error Invalid outside procedure.

PS3: You could (partly) check your code with Debug -> Compile VBAProject in the VB editor. All compile errors will pop.

PS4: Check also Put Excel-VBA code in module or sheet?.

PS5: You might be not able to declare a global variable in, say, Sheet1, and use it in code from other workbook (reading; I did not test this point, so this issue is yet to be confirmed as such). But you do not mean to do that in your example, anyway.

PS6: There are several cases that lead to ambiguity in case of not fully qualifying global variables. You may tinker a little to find them. They are compile errors.

How can I reorder my divs using only CSS?

Here's a solution:

#firstDiv {
    position:absolute; top:100%;
#wrapper {

But I suspect you have some content that follows the wrapper div...

vertical-align: middle with Bootstrap 2

If I remember correctly from my own use of bootstrap, the .spanN classes are floated, which automatically makes them behave as display: block. To make display: table-cell work, you need to remove the float.

How to implement the Softmax function in Python

Here you can find out why they used - max.

From there:

"When you’re writing code for computing the Softmax function in practice, the intermediate terms may be very large due to the exponentials. Dividing large numbers can be numerically unstable, so it is important to use a normalization trick."

Convert json data to a html table

Thanks all for your replies. I wrote one myself. Please note that this uses jQuery.

Code snippet:

var myList = [_x000D_
  { "name": "abc", "age": 50 },_x000D_
  { "age": "25", "hobby": "swimming" },_x000D_
  { "name": "xyz", "hobby": "programming" }_x000D_
// Builds the HTML Table out of myList._x000D_
function buildHtmlTable(selector) {_x000D_
  var columns = addAllColumnHeaders(myList, selector);_x000D_
  for (var i = 0; i < myList.length; i++) {_x000D_
    var row$ = $('<tr/>');_x000D_
    for (var colIndex = 0; colIndex < columns.length; colIndex++) {_x000D_
      var cellValue = myList[i][columns[colIndex]];_x000D_
      if (cellValue == null) cellValue = "";_x000D_
// Adds a header row to the table and returns the set of columns._x000D_
// Need to do union of keys from all records as some records may not contain_x000D_
// all records._x000D_
function addAllColumnHeaders(myList, selector) {_x000D_
  var columnSet = [];_x000D_
  var headerTr$ = $('<tr/>');_x000D_
  for (var i = 0; i < myList.length; i++) {_x000D_
    var rowHash = myList[i];_x000D_
    for (var key in rowHash) {_x000D_
      if ($.inArray(key, columnSet) == -1) {_x000D_
  return columnSet;_x000D_
<script src=""></script>_x000D_
<body onLoad="buildHtmlTable('#excelDataTable')">_x000D_
  <table id="excelDataTable" border="1">_x000D_

<modules runAllManagedModulesForAllRequests="true" /> Meaning

Modules Preconditions:

The IIS core engine uses preconditions to determine when to enable a particular module. Performance reasons, for example, might determine that you only want to execute managed modules for requests that also go to a managed handler. The precondition in the following example (precondition="managedHandler") only enables the forms authentication module for requests that are also handled by a managed handler, such as requests to .aspx or .asmx files:

<add name="FormsAuthentication" type="System.Web.Security.FormsAuthenticationModule" preCondition="managedHandler" />

If you remove the attribute precondition="managedHandler", Forms Authentication also applies to content that is not served by managed handlers, such as .html, .jpg, .doc, but also for classic ASP (.asp) or PHP (.php) extensions. See "How to Take Advantage of IIS Integrated Pipeline" for an example of enabling ASP.NET modules to run for all content.

You can also use a shortcut to enable all managed (ASP.NET) modules to run for all requests in your application, regardless of the "managedHandler" precondition.

To enable all managed modules to run for all requests without configuring each module entry to remove the "managedHandler" precondition, use the runAllManagedModulesForAllRequests property in the <modules> section:

<modules runAllManagedModulesForAllRequests="true" />    

When you use this property, the "managedHandler" precondition has no effect and all managed modules run for all requests.

Copied from IIS Modules Overview: Preconditions

Make Bootstrap Popover Appear/Disappear on Hover instead of Click

The functionality, you described, can be easily achieved using the Bootstrap tooltip.

<button id="example1" data-toggle="tooltip">Tooltip on left</button>

Then call tooltip() function for the element.


Remove excess whitespace from within a string

Not sure exactly what you want but here are two situations:

  1. If you are just dealing with excess whitespace on the beginning or end of the string you can use trim(), ltrim() or rtrim() to remove it.

  2. If you are dealing with extra spaces within a string consider a preg_replace of multiple whitespaces " "* with a single whitespace " ".


$foo = preg_replace('/\s+/', ' ', $foo);

show more/Less text with just HTML and JavaScript

I'm not an expert, but I did a lot of looking to implement this for myself. I found something different, but modified it to accomplish this. It's really quite simple:

The function takes two arguments, a div containing only the words "show more" [or whatever] and a div containing the originally hidden text and the words "show less." The function displays the one div and hides the other.

NOTE: If more than one show/hide on page, assign different ids to divs Colors can be changed

<p>Here is text that is originally displayed</p>

<div id="div1">
<p style="color:red;" onclick="showFunction('div2','div1')">show more</p></div>
<div id="div2" style="display:none">

<p>Put expanded text here</p>

<p style="color:red;" onclick="showFunction('div1','div2')">show less</p></div>

<p>more text</p>

Here is the Script:

function showFunction(diva, divb) {
    var x = document.getElementById(diva);
    var y = document.getElementById(divb);
 = 'block';
 = 'none';

How can I create a self-signed cert for localhost?

Although this post is post is tagged for Windows, it is relevant question on OS X that I have not seen answers for elsewhere. Here are steps to create a self-signed cert for localhost on OS X:

# Use 'localhost' for the 'Common name'
openssl req -x509 -sha256 -nodes -newkey rsa:2048 -days 365 -keyout localhost.key -out localhost.crt

# Add the cert to your keychain
open localhost.crt

In Keychain Access, double-click on this new localhost cert. Expand the arrow next to "Trust" and choose to "Always trust". Chrome and Safari should now trust this cert. For example, if you want to use this cert with node.js:

var options = {
    key: fs.readFileSync('/path/to/localhost.key').toString(),
    cert: fs.readFileSync('/path/to/localhost.crt').toString(),
    honorCipherOrder: true,
    secureProtocol: 'TLSv1_2_method'

var server = require('https').createServer(options, app);

How can I check whether an array is null / empty?

You can also check whether there is any elements in the array by finding out its length, then put it into if-else statement to check whether it is null.

int[] k = new int[3];
if(k.length == 0)
//do something

Python 3 TypeError: must be str, not bytes with sys.stdout.write()

While the accepted answer will work fine if the bytes you have from your subprocess are encoded using sys.stdout.encoding (or a compatible encoding, like reading from a tool that outputs ASCII and your stdout uses UTF-8), the correct way to write arbitrary bytes to stdout is:


This will just output the bytes as-is, without trying to treat them as text-in-some-encoding.

Incorrect string value: '\xF0\x9F\x8E\xB6\xF0\x9F...' MySQL

Change database charset and collation

    CHARACTER SET = utf8mb4
    COLLATE = utf8mb4_unicode_ci;

change specific table's charset and collation

    COLLATE utf8mb4_unicode_ci;

change connection charset in mysql driver





From this article

Uncaught TypeError: Object #<Object> has no method 'movingBoxes'

i had the same problem i had linked jquery twice . The later version was overwriting my plugin.

I just removed the later jquery it started working.

Limit Get-ChildItem recursion depth

As of powershell 5.0, you can now use the -Depth parameter in Get-ChildItem!

You combine it with -Recurse to limit the recursion.

Get-ChildItem -Recurse -Depth 2

Apache HttpClient Interim Error: NoHttpResponseException

I have faced same issue, I resolved by adding "connection: close" as extention,

Step 1: create a new class ConnectionCloseExtension

import com.github.tomakehurst.wiremock.common.FileSource;
import com.github.tomakehurst.wiremock.extension.Parameters;
import com.github.tomakehurst.wiremock.extension.ResponseTransformer;
import com.github.tomakehurst.wiremock.http.HttpHeader;
import com.github.tomakehurst.wiremock.http.HttpHeaders;
import com.github.tomakehurst.wiremock.http.Request;
import com.github.tomakehurst.wiremock.http.Response;

public class ConnectionCloseExtension extends ResponseTransformer {
  public Response transform(Request request, Response response, FileSource files, Parameters parameters) {
    return Response.Builder
            .plus(new HttpHeader("Connection", "Close")))

  public String getName() {
    return "ConnectionCloseExtension";

Step 2: set extension class in wireMockServer like below,

final WireMockServer wireMockServer = new WireMockServer(options()

Add text to Existing PDF using Python

cpdf will do the job from the command-line. It isn't python, though (afaik):

cpdf -add-text "Line of text" input.pdf -o output .pdf

How to use EOF to run through a text file in C?

How you detect EOF depends on what you're using to read the stream:

function                  result on EOF or error                    
--------                  ----------------------
fgets()                   NULL
fscanf()                  number of succesful conversions
                            less than expected
fgetc()                   EOF
fread()                   number of elements read
                            less than expected

Check the result of the input call for the appropriate condition above, then call feof() to determine if the result was due to hitting EOF or some other error.

Using fgets():

 char buffer[BUFFER_SIZE];
 while (fgets(buffer, sizeof buffer, stream) != NULL)
   // process buffer
 if (feof(stream))
   // hit end of file
   // some other error interrupted the read

Using fscanf():

char buffer[BUFFER_SIZE];
while (fscanf(stream, "%s", buffer) == 1) // expect 1 successful conversion
  // process buffer
if (feof(stream)) 
  // hit end of file
  // some other error interrupted the read

Using fgetc():

int c;
while ((c = fgetc(stream)) != EOF)
  // process c
if (feof(stream))
  // hit end of file
  // some other error interrupted the read

Using fread():

char buffer[BUFFER_SIZE];
while (fread(buffer, sizeof buffer, 1, stream) == 1) // expecting 1 
                                                     // element of size
                                                     // BUFFER_SIZE
   // process buffer
if (feof(stream))
  // hit end of file
  // some other error interrupted read

Note that the form is the same for all of them: check the result of the read operation; if it failed, then check for EOF. You'll see a lot of examples like:

  fscanf(stream, "%s", buffer);

This form doesn't work the way people think it does, because feof() won't return true until after you've attempted to read past the end of the file. As a result, the loop executes one time too many, which may or may not cause you some grief.

Fastest way to convert string to integer in PHP

I've just set up a quick benchmarking exercise:

Function             time to run 1 million iterations
(int) "123":                0.55029
intval("123"):              1.0115  (183%)

(int) "0":                  0.42461
intval("0"):                0.95683 (225%)

(int) int:                  0.1502
intval(int):                0.65716 (438%)

(int) array("a", "b"):      0.91264
intval(array("a", "b")):    1.47681 (162%)

(int) "hello":              0.42208
intval("hello"):            0.93678 (222%)

On average, calling intval() is two and a half times slower, and the difference is the greatest if your input already is an integer.

I'd be interested to know why though.

Update: I've run the tests again, this time with coercion (0 + $var)

| INPUT ($x)      |  (int) $x  |intval($x) |  0 + $x   |
| "123"           |   0.51541  |  0.96924  |  0.33828  |
| "0"             |   0.42723  |  0.97418  |  0.31353  |
| 123             |   0.15011  |  0.61690  |  0.15452  |
| array("a", "b") |   0.8893   |  1.45109  |  err!     |
| "hello"         |   0.42618  |  0.88803  |  0.1691   |

Addendum: I've just come across a slightly unexpected behaviour which you should be aware of when choosing one of these methods:

$x = "11";
(int) $x;      // int(11)
intval($x);    // int(11)
$x + 0;        // int(11)

$x = "0x11";
(int) $x;      // int(0)
intval($x);    // int(0)
$x + 0;        // int(17) !

$x = "011";
(int) $x;      // int(11)
intval($x);    // int(11)
$x + 0;        // int(11) (not 9)

Tested using PHP 5.3.1

Automapper missing type map configuration or unsupported mapping - Error

I had same issue in .Net Core. Because my base dto class(i give it as a type in startup for automapper assembly) was in different project. Automapper tried to search for profiles in base class project. But my dto's were in different project. I moved my base class. And problem solved. This may help for some persons.

How do I pass multiple parameters into a function in PowerShell?

If you don't know (or care) how many arguments you will be passing to the function, you could also use a very simple approach like;


function FunctionName()
    Write-Host $args

That would print out all arguments. For example:

FunctionName a b c 1 2 3


a b c 1 2 3

I find this particularly useful when creating functions that use external commands that could have many different (and optional) parameters, but relies on said command to provide feedback on syntax errors, etc.

Here is a another real-world example (creating a function to the tracert command, which I hate having to remember the truncated name);


Function traceroute
    Start-Process -FilePath "$env:systemroot\system32\tracert.exe" -ArgumentList $args -NoNewWindow

Java Compare Two Lists


Here are two versions. One using ArrayList and other using HashSet

Compare them and create your own version from this, until you get what you need.

This should be enough to cover the:

P.S: It is not a school assignment :) So if you just guide me it will be enough

part of your question.

continuing with the original answer:

You may use a java.util.Collection and/or java.util.ArrayList for that.

The retainAll method does the following:

Retains only the elements in this collection that are contained in the specified collection

see this sample:

import java.util.Collection;
import java.util.ArrayList;
import java.util.Arrays;

public class Repeated {
    public static void main( String  [] args ) {
        Collection listOne = new ArrayList(Arrays.asList("milan","dingo", "elpha", "hafil", "meat", "iga", "neeta.peeta"));
        Collection listTwo = new ArrayList(Arrays.asList("hafil", "iga", "binga", "mike", "dingo"));

        listOne.retainAll( listTwo );
        System.out.println( listOne );


For the second part ( similar values ) you may use the removeAll method:

Removes all of this collection's elements that are also contained in the specified collection.

This second version gives you also the similar values and handles repeated ( by discarding them).

This time the Collection could be a Set instead of a List ( the difference is, the Set doesn't allow repeated values )

import java.util.Collection;
import java.util.HashSet;
import java.util.Arrays;

class Repeated {
      public static void main( String  [] args ) {

          Collection<String> listOne = Arrays.asList("milan","iga",

          Collection<String> listTwo = Arrays.asList("hafil",

          Collection<String> similar = new HashSet<String>( listOne );
          Collection<String> different = new HashSet<String>();
          different.addAll( listOne );
          different.addAll( listTwo );

          similar.retainAll( listTwo );
          different.removeAll( similar );

          System.out.printf("One:%s%nTwo:%s%nSimilar:%s%nDifferent:%s%n", listOne, listTwo, similar, different);


$ java Repeated
One:[milan, iga, dingo, iga, elpha, iga, hafil, iga, meat, iga, neeta.peeta, iga]

Two:[hafil, iga, binga, mike, dingo, dingo, dingo]

Similar:[dingo, iga, hafil]

Different:[mike, binga, milan, meat, elpha, neeta.peeta]

If it doesn't do exactly what you need, it gives you a good start so you can handle from here.

Question for the reader: How would you include all the repeated values?

Amazon Interview Question: Design an OO parking lot

In an Object Oriented parking lot, there will be no need for attendants because the cars will "know how to park".

Finding a usable car on the lot will be difficult; the most common models will either have all their moving parts exposed as public member variables, or they will be "fully encapsulated" cars with no windows or doors.

The parking spaces in our OO parking lot will not match the size and shape of the cars (an "impediance mismatch" between the spaces and the cars)

License tags on our lot will have a dot between each letter and digit. Handicaped parking will only be available for licenses beginning with "_", and licenses beginning with "m_" will be towed.

How to open a file for both reading and writing?

Here's how you read a file, and then write to it (overwriting any existing data), without closing and reopening:

with open(filename, "r+") as f:
    data =

Bootstrap datepicker disabling past dates without current date


startDate: '-0d'


    startDate: '-0d',
    changeMonth: true

Clear data in MySQL table with PHP?


unless you need to preserve the current value of the AUTO_INCREMENT sequence, in which case you'd probably prefer


though if the time of the operation matters, saving the AUTO_INCREMENT value, truncating the table, and then restoring the value using


will happen a lot faster.

How to query GROUP BY Month in a Year

For Oracle:

select EXTRACT(month from DATE_CREATED), sum(Num_of_Pictures)
from pictures_table
group by EXTRACT(month from DATE_CREATED);

Inserting data to table (mysqli insert)

Warning: Never ever refer to w3schools for learning purposes. They have so many mistakes in their tutorials.

According to the mysqli_query documentation, the first parameter must be a connection string:

$link = mysqli_connect("localhost","root","","web_table");

mysqli_query($link,"INSERT INTO web_formitem (`ID`, `formID`, `caption`, `key`, `sortorder`, `type`, `enabled`, `mandatory`, `data`)
VALUES (105, 7, 'Tip izdelka (6)', 'producttype_6', 42, 5, 1, 0, 0)") 
or die(mysqli_error($link));

Note: Add backticks ` for column names in your insert query as some of your column names are reserved words.

Python readlines() usage and efficient practice for reading

The short version is: The efficient way to use readlines() is to not use it. Ever.

I read some doc notes on readlines(), where people has claimed that this readlines() reads whole file content into memory and hence generally consumes more memory compared to readline() or read().

The documentation for readlines() explicitly guarantees that it reads the whole file into memory, and parses it into lines, and builds a list full of strings out of those lines.

But the documentation for read() likewise guarantees that it reads the whole file into memory, and builds a string, so that doesn't help.

On top of using more memory, this also means you can't do any work until the whole thing is read. If you alternate reading and processing in even the most naive way, you will benefit from at least some pipelining (thanks to the OS disk cache, DMA, CPU pipeline, etc.), so you will be working on one batch while the next batch is being read. But if you force the computer to read the whole file in, then parse the whole file, then run your code, you only get one region of overlapping work for the entire file, instead of one region of overlapping work per read.

You can work around this in three ways:

  1. Write a loop around readlines(sizehint), read(size), or readline().
  2. Just use the file as a lazy iterator without calling any of these.
  3. mmap the file, which allows you to treat it as a giant string without first reading it in.

For example, this has to read all of foo at once:

with open('foo') as f:
    lines = f.readlines()
    for line in lines:

But this only reads about 8K at a time:

with open('foo') as f:
    while True:
        lines = f.readlines(8192)
        if not lines:
        for line in lines:

And this only reads one line at a time—although Python is allowed to (and will) pick a nice buffer size to make things faster.

with open('foo') as f:
    while True:
        line = f.readline()
        if not line:

And this will do the exact same thing as the previous:

with open('foo') as f:
    for line in f:


but should the garbage collector automatically clear that loaded content from memory at the end of my loop, hence at any instant my memory should have only the contents of my currently processed file right ?

Python doesn't make any such guarantees about garbage collection.

The CPython implementation happens to use refcounting for GC, which means that in your code, as soon as file_content gets rebound or goes away, the giant list of strings, and all of the strings within it, will be freed to the freelist, meaning the same memory can be reused again for your next pass.

However, all those allocations, copies, and deallocations aren't free—it's much faster to not do them than to do them.

On top of that, having your strings scattered across a large swath of memory instead of reusing the same small chunk of memory over and over hurts your cache behavior.

Plus, while the memory usage may be constant (or, rather, linear in the size of your largest file, rather than in the sum of your file sizes), that rush of mallocs to expand it the first time will be one of the slowest things you do (which also makes it much harder to do performance comparisons).

Putting it all together, here's how I'd write your program:

for filename in os.listdir(input_dir):
    with open(filename, 'rb') as f:
        if filename.endswith(".gz"):
            f =
        words = (line.split(delimiter) for line in f)
        ... my logic ...  

Or, maybe:

for filename in os.listdir(input_dir):
    if filename.endswith(".gz"):
        f =, 'rb')
        f = open(filename, 'rb')
    with contextlib.closing(f):
        words = (line.split(delimiter) for line in f)
        ... my logic ...

struct in class

I'd like to add another use case for an internal struct/class and its usability. An inner struct is often used to declare a data only member of a class that packs together relevant information and as such we can enclose it all in a struct instead of loose data members lying around.

The inner struct/class is but a data only compartment, ie it has no functions (except maybe constructors).

#include <iostream>

class E
    // E functions..
    struct X
        int v;
        // X variables..
    } x;
    // E variables..

int main()
    E e;
    e.x.v = 9;
    std::cout << e.x.v << '\n';
    E e2{5};
    std::cout << e2.x.v << '\n';

    // You can instantiate an X outside E like so:
    //E::X xOut{24};
    //std::cout << xOut.v << '\n';
    // But you shouldn't want to in this scenario.
    // X is only a data member (containing other data members)
    // for use only inside the internal operations of E
    // just like the other E's data members

This practice is widely used in graphics, where the inner struct will be sent as a Constant Buffer to HLSL. But I find it neat and useful in many cases.

How do I convert a string to a number in PHP?

Yes, there is a similar method in PHP, but it is so little known that you will rarely hear about it. It is an arithmetic operator called "identity", as described here:

Aritmetic Operators

To convert a numeric string to a number, do as follows:

$a = +$a;

The OLE DB provider "Microsoft.ACE.OLEDB.12.0" for linked server "(null)"

This solves the issue. For some reason SQL Server does not like the default MSSQLSERVER account. Switching it to a local user account resolves the issue.

How to merge 2 JSON objects from 2 files using jq?

Use jq -s add:

$ echo '{"a":"foo","b":"bar"} {"c":"baz","a":0}' | jq -s add
  "a": 0,
  "b": "bar",
  "c": "baz"

This reads all JSON texts from stdin into an array (jq -s does that) then it "reduces" them.

(add is defined as def add: reduce .[] as $x (null; . + $x);, which iterates over the input array's/object's values and adds them. Object addition == merge.)

How can I create a progress bar in Excel VBA?

About the progressbar control in a userform, it won't show any progress if you don't use the repaint event. You have to code this event inside the looping (and obviously increment the progressbar value).

Example of use:


Timer Interval 1000 != 1 second?

Instead of Tick event, use Elapsed event.

timer.Elapsed += new EventHandler(TimerEventProcessor);

and change the signiture of TimerEventProcessor method;

private void TimerEventProcessor(object sender, ElapsedEventArgs e)
  label1.Text = _counter.ToString();
  _counter += 1;

Using FolderBrowserDialog in WPF application

You need to add a reference to System.Windows.Forms.dll, then use the System.Windows.Forms.FolderBrowserDialog class.

Adding using WinForms = System.Windows.Forms; will be helpful.

Structs data type in php?

A public class is one option, if you want something more encapsulated you can use an abstract/anonymous class combination. My favorite part is that autocomplete still works (for PhpStorm) for this but I don't have a public class sitting around.


final class MyParentClass
     * @return MyStruct[]
    public function getData(): array
        return array(
            $this->createMyObject("One", 1.0, new DateTime("now")),
            $this->createMyObject("Two", 2.0, new DateTime("tommorow"))

    private function createMyObject(string $description, float $magnitude, DateTime $timeStamp): MyStruct
        return new class(func_get_args()) extends MyStruct {
            protected function __construct(array $args)
                $this->description = $args[0];
                $this->magnitude = $args[1];
                $this->timeStamp = $args[2];

abstract class MyStruct
    public string $description;
    public float $magnitude;
    public DateTime $timeStamp;

How to fix Cannot find module 'typescript' in Angular 4?

If you don't have particular needs, I suggest to install Typescript locally.

NPM Installation Method

npm install --global typescript # Global installation
npm install --save-dev typescript # Local installation

Yarn Installation Method

yarn global add typescript # Global installation
yarn add --dev typescript # Local installation

Java BigDecimal: Round to the nearest whole value

You can use setScale() to reduce the number of fractional digits to zero. Assuming value holds the value to be rounded:

BigDecimal scaled = value.setScale(0, RoundingMode.HALF_UP);
System.out.println(value + " -> " + scaled);

Using round() is a bit more involved as it requires you to specify the number of digits to be retained. In your examples this would be 3, but this is not valid for all values:

BigDecimal rounded = value.round(new MathContext(3, RoundingMode.HALF_UP));
System.out.println(value + " -> " + rounded);

(Note that BigDecimal objects are immutable; both setScale and round will return a new object.)

How do I make calls to a REST API using C#?

A solution in ASP.NET Core:

using Newtonsoft.Json;
using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using System.Configuration;

namespace WebApp
    public static class HttpHelper
        // In my case this is https://localhost:44366/
        private static readonly string apiBasicUri = ConfigurationManager.AppSettings["apiBasicUri"];

        public static async Task Post<T>(string url, T contentValue)
            using (var client = new HttpClient())
                client.BaseAddress = new Uri(apiBasicUri);
                var content = new StringContent(JsonConvert.SerializeObject(contentValue), Encoding.UTF8, "application/json");
                var result = await client.PostAsync(url, content);

        public static async Task Put<T>(string url, T stringValue)
            using (var client = new HttpClient())
                client.BaseAddress = new Uri(apiBasicUri);
                var content = new StringContent(JsonConvert.SerializeObject(stringValue), Encoding.UTF8, "application/json");
                var result = await client.PutAsync(url, content);

        public static async Task<T> Get<T>(string url)
            using (var client = new HttpClient())
                client.BaseAddress = new Uri(apiBasicUri);
                var result = await client.GetAsync(url);
                string resultContentString = await result.Content.ReadAsStringAsync();
                T resultContent = JsonConvert.DeserializeObject<T>(resultContentString);
                return resultContent;

        public static async Task Delete(string url)
            using (var client = new HttpClient())
                client.BaseAddress = new Uri(apiBasicUri);
                var result = await client.DeleteAsync(url);

To post, use something like this:

await HttpHelper.Post<Setting>($"/api/values/{id}", setting);

Example for delete:

await HttpHelper.Delete($"/api/values/{id}");

Example to get a list:

List<ClaimTerm> claimTerms = await HttpHelper.Get<List<ClaimTerm>>("/api/values/");

Example to get only one:

ClaimTerm processedClaimImage = await HttpHelper.Get<ClaimTerm>($"/api/values/{id}");

Does a foreign key automatically create an index?

SQL Server autocreates indices for Primary Keys, but not for Foreign Keys. Create the index for the Foreign Keys. It's probably worth the overhead.

What are SP (stack) and LR in ARM?

LR is link register used to hold the return address for a function call.

SP is stack pointer. The stack is generally used to hold "automatic" variables and context/parameters across function calls. Conceptually you can think of the "stack" as a place where you "pile" your data. You keep "stacking" one piece of data over the other and the stack pointer tells you how "high" your "stack" of data is. You can remove data from the "top" of the "stack" and make it shorter.

From the ARM architecture reference:

SP, the Stack Pointer

Register R13 is used as a pointer to the active stack.

In Thumb code, most instructions cannot access SP. The only instructions that can access SP are those designed to use SP as a stack pointer. The use of SP for any purpose other than as a stack pointer is deprecated. Note Using SP for any purpose other than as a stack pointer is likely to break the requirements of operating systems, debuggers, and other software systems, causing them to malfunction.

LR, the Link Register

Register R14 is used to store the return address from a subroutine. At other times, LR can be used for other purposes.

When a BL or BLX instruction performs a subroutine call, LR is set to the subroutine return address. To perform a subroutine return, copy LR back to the program counter. This is typically done in one of two ways, after entering the subroutine with a BL or BLX instruction:

• Return with a BX LR instruction.

• On subroutine entry, store LR to the stack with an instruction of the form: PUSH {,LR} and use a matching instruction to return: POP {,PC} ...

This link gives an example of a trivial subroutine.

Here is an example of how registers are saved on the stack prior to a call and then popped back to restore their content.

How can I split this comma-delimited string in Python?

You don't want regular expressions here.

s = "144,1231693144,26959535291011309493156476344723991336010898738574164086137773096960,26959535291011309493156476344723991336010898738574164086137773096960,1.00,4295032833,1563,2747941 288,1231823695,26959535291011309493156476344723991336010898738574164086137773096960,26959535291011309493156476344723991336010898738574164086137773096960,1.00,4295032833,909,4725008"

print s.split(',')

Gives you:

['144', '1231693144', '26959535291011309493156476344723991336010898738574164086137773096960', '26959535291011309493156476344723991336010898738574164086137773096960', '1.00
', '4295032833', '1563', '2747941 288', '1231823695', '26959535291011309493156476344723991336010898738574164086137773096960', '26959535291011309493156476344723991336010898
738574164086137773096960', '1.00', '4295032833', '909', '4725008']

JavaScript moving element in the DOM

var swap = function () {
    var divs = document.getElementsByTagName('div');
    var div1 = divs[0];
    var div2 = divs[1];
    var div3 = divs[2];

    div3.parentNode.insertBefore(div1, div3);
    div1.parentNode.insertBefore(div3, div2);

This function may seem strange, but it heavily relies on standards in order to function properly. In fact, it may seem to function better than the jQuery version that tvanfosson posted which seems to do the swap only twice.

What standards peculiarities does it rely on?

insertBefore Inserts the node newChild before the existing child node refChild. If refChild is null, insert newChild at the end of the list of children. If newChild is a DocumentFragment object, all of its children are inserted, in the same order, before refChild. If the newChild is already in the tree, it is first removed.

How does the vim "write with sudo" trick work?

In the executed command line, % stands for the current file name. This is documented in :help cmdline-special:

In Ex commands, at places where a file name can be used, the following
characters have a special meaning.
        %       Is replaced with the current file name.

As you've already found out, :w !cmd pipes the contents of the current buffer to another command. What tee does is copy standard input to one or more files, and also to standard output. Therefore, :w !sudo tee % > /dev/null effectively writes the contents of the current buffer to the current file while being root. Another command that can be used for this is dd:

:w !sudo dd of=% > /dev/null

As a shortcut, you can add this mapping to your .vimrc:

" Force saving files that require root permission 
cnoremap w!! w !sudo tee > /dev/null %

With the above you can type :w!!<Enter> to save the file as root.

Strtotime() doesn't work with dd/mm/YYYY format

If you know it's in dd/mm/YYYY, you can do:

    $regex = '#([/d]{1,2})/([/d]{1,2})/([/d]{2,4})#';
    $match = array();
    if (preg_match($regex, $date, $match)) {
        if (strlen($match[3]) == 2) {
            $match[3] = '20' . $match[3];
        return mktime(0, 0, 0, $match[2], $match[1], $match[3]);
    return strtotime($date);

It will match dates in the form d/m/YY or dd/mm/YYYY (or any combination of the two)...

If you want to support more separators than just /, you can change the regex to:

    $regex = '#([\d]{1,2})[/-]([\d]{1,2})[/-]([\d]{2,4})#';

And then add any characters you want into the [/-] bit (Note, the - character needs to be last)

Rotating a point about another point (2D)

If you rotate point (px, py) around point (ox, oy) by angle theta you'll get:

p'x = cos(theta) * (px-ox) - sin(theta) * (py-oy) + ox

p'y = sin(theta) * (px-ox) + cos(theta) * (py-oy) + oy

this is an easy way to rotate a point in 2D.

What is the time complexity of indexing, inserting and removing from common data structures?

Red-Black trees:

  • Insert - O(log n)
  • Retrieve - O(log n)
  • Delete - O(log n)

Communication between tabs or windows

Another method that people should consider using is Shared Workers. I know it's a cutting edge concept, but you can create a relay on a Shared Worker that is MUCH faster than localstorage, and doesn't require a relationship between the parent/child window, as long as you're on the same origin.

See my answer here for some discussion I made about this.

Passing a string array as a parameter to a function java

All the answers above are correct. But just note that you'll be passing the reference to the string array when you pass like this. If you make any modifications to the array in your called function, it will be reflected in the calling function also.

There is another concept called variable arguments in Java which you can look into. It basically works like this. Eg:-

 String concat (String ... strings)
      StringBuilder sb = new StringBuilder ();
      for (int i = 0; i &lt; strings.length; i++)
           sb.append (strings [i]);
      return sb.toString ();

Here we can call the function like concat(a,b,c,d) or any number of params you want.

More Info:

Skip Git commit hooks

Maybe (from git commit man page):

git commit --no-verify


This option bypasses the pre-commit and commit-msg hooks. See also githooks(5).

As commented by Blaise, -n can have a different role for certain commands.
For instance, git push -n is actually a dry-run push.
Only git push --no-verify would skip the hook.

Note: Git 2.14.x/2.15 improves the --no-verify behavior:

See commit 680ee55 (14 Aug 2017) by Kevin Willford (``).
(Merged by Junio C Hamano -- gitster -- in commit c3e034f, 23 Aug 2017)

commit: skip discarding the index if there is no pre-commit hook

"git commit" used to discard the index and re-read from the filesystem just in case the pre-commit hook has updated it in the middle; this has been optimized out when we know we do not run the pre-commit hook.

Davi Lima points out in the comments the git cherry-pick does not support --no-verify.
So if a cherry-pick triggers a pre-commit hook, you might, as in this blog post, have to comment/disable somehow that hook in order for your git cherry-pick to proceed.
The same process would be necessary in case of a git rebase --continue, after a merge conflict resolution.

How to quickly clear a JavaScript Object?

Well, at the risk of making things too easy...

for (var member in myObject) delete myObject[member];

...would seem to be pretty effective in cleaning the object in one line of code with a minimum of scary brackets. All members will be truly deleted instead of left as garbage.

Obviously if you want to delete the object itself, you'll still have to do a separate delete() for that.

Visual Studio move project to a different folder

I wanted the changes in Git to be shown as moves/renames instead of delete & adds. So I did a combo of the above and this post.

mkdir subdirectory
git mv -k ./* ./subdirectory
# check to make sure everything moved (see below)
git commit

And adjust the paths of the projects and of the assemblies from the nuget Pkg's in the sln file via a text editor.

jquery draggable: how to limit the draggable area?

See excerpt from official documentation for containment option:


Default: false

Constrains dragging to within the bounds of the specified element or region.
Multiple types supported:

  • Selector: The draggable element will be contained to the bounding box of the first element found by the selector. If no element is found, no containment will be set.
  • Element: The draggable element will be contained to the bounding box of this element.
  • String: Possible values: "parent", "document", "window".
  • Array: An array defining a bounding box in the form [ x1, y1, x2, y2 ].

Code examples:
Initialize the draggable with the containment option specified:

$( ".selector" ).draggable({
    containment: "parent" 

Get or set the containment option, after initialization:

// Getter
var containment = $( ".selector" ).draggable( "option", "containment" );
// Setter
$( ".selector" ).draggable( "option", "containment", "parent" );

Extracting specific columns in numpy array

you can also use extractedData=data([:,1],[:,9])

The shortest possible output from git log containing author and date

git --no-pager log --pretty=tformat:"%C(yellow)%h %C(cyan)%ad %Cblue%an%C(auto)%d %Creset%s" --graph --date=format:"%Y-%m-%d %H:%M" -25 

I use alias

alias gitlog='git --no-pager log --pretty=tformat:"%C(yellow)%h %C(cyan)%ad %Cblue%an%C(auto)%d %Creset%s" --graph --date=format:"%Y-%m-%d %H:%M" -25'

Differences: I use tformat and isodate without seconds and time zones , with --no-pager you will see colors

Bootstrap - 5 column layout

If you want to enforce the 20% column width for every row that you have, even if you don't have 5 columns in some rows, you will have to add the following to your css or scss file:

    .col-lg-5-cols {
        position: relative;
        width: 100%;
        min-height: 1px;
        padding-right: 15px;
        padding-left: 15px;

    .col-xs-5-cols {
        -ms-flex: 0 0 20%;
        flex: 0 0 20%;
        max-width: 20%;
    @media (min-width: 768px) {
        .col-sm-5-cols {
            -ms-flex: 0 0 20%;
            flex: 0 0 20%;
            max-width: 20%;
    @media (min-width: 992px) {
        .col-md-5-cols {
            -ms-flex: 0 0 20%;
            flex: 0 0 20%;
            max-width: 20%;
    @media (min-width: 1200px) {
        .col-lg-5-cols {
            -ms-flex: 0 0 20%;
            flex: 0 0 20%;
            max-width: 20%;

And in your html, use the added class as following:

<div class="row">
        <div class="col-lg-5-cols"></div>
        <div class="col-lg-5-cols"></div>
        <div class="col-lg-5-cols"></div>
        <div class="col-lg-5-cols"></div>
        <div class="col-lg-5-cols"></div>

JQUERY ajax passing value from MVC View to Controller

$('#btnSaveComments').click(function () {
    var comments = $('#txtComments').val();
    var selectedId = $('#hdnSelectedId').val();

        url: '<%: Url.Action("SaveComments")%>',
        data: { 'id' : selectedId, 'comments' : comments },
        type: "post",
        cache: false,
        success: function (savingStatu`enter code here`s) {
        error: function (xhr, ajaxOptions, thrownError) {
            $('#lblCommentsNotification').text("Error encountered while saving the comments.");

How to append new data onto a new line

I presume that all you are wanting is simple string concatenation:

def storescores():

   hs = open("hst.txt","a")
   hs.write(name + " ")

Alternatively, change the " " to "\n" for a newline.

What is the difference between children and childNodes in JavaScript?

Element.children returns only element children, while Node.childNodes returns all node children. Note that elements are nodes, so both are available on elements.

I believe childNodes is more reliable. For example, MDC (linked above) notes that IE only got children right in IE 9. childNodes provides less room for error by browser implementors.

How to go to each directory and execute a command?

While one liners are good for quick and dirty usage, I prefer below more verbose version for writing scripts. This is the template I use which takes care of many edge cases and allows you to write more complex code to execute on a folder. You can write your bash code in the function dir_command. Below, dir_coomand implements tagging each repository in git as an example. Rest of the script calls dir_command for each folder in directory. The example of iterating through only given set of folder is also include.


#Use set -x if you want to echo each command while getting executed
#set -x

#Save current directory so we can restore it later
#Save command line arguments so functions can access it

#Put your code in this function
#To access command line arguments use syntax ${args[1]} etc
function dir_command {
    #This example command implements doing git status for folder
    cd $1
    echo "$(tput setaf 2)$1$(tput sgr 0)"
    git tag -a ${args[0]} -m "${args[1]}"
    git push --tags
    cd ..

#This loop will go to each immediate child and execute dir_command
find . -maxdepth 1 -type d \( ! -name . \) | while read dir; do
   dir_command "$dir/"

#This example loop only loops through give set of folders    
declare -a dirs=("dir1" "dir2" "dir3")
for dir in "${dirs[@]}"; do
    dir_command "$dir/"

#Restore the folder
cd "$cur"

Python to open Chrome browser

if sys.platform[:3] == "win":
    # First try to use the default Windows browser
    register("windows-default", WindowsDefault)

    # Detect some common Windows browsers, fallback to IE
    iexplore = os.path.join(os.environ.get("PROGRAMFILES", "C:\\Program Files"),
                            "Mozilla Firefox\\FIREFOX.EXE")
    for browser in ("firefox", "firebird", "seamonkey", "mozilla",
                    "netscape", "opera", iexplore):
        if shutil.which(browser):
            register(browser, None, BackgroundBrowser(browser))

100% Work....See line number 535-545..Change the path of iexplore to firefox or Chrome According to your requirement... in my case change path I Mention in the above code for firefox setting......

Is it possible to run JavaFX applications on iOS, Android or Windows Phone 8?

Possible. You can get commercial sport also.

JavaFXPorts is the name of the open source project maintained by Gluon that develops the code necessary for Java and JavaFX to run well on mobile and embedded hardware. The goal of this project is to contribute as much back to the OpenJFX project wherever possible, and when not possible, to maintain the minimal number of changes necessary to enable the goals of JavaFXPorts. Gluon takes the JavaFXPorts source code and compiles it into binaries ready for deployment onto iOS, Android, and embedded hardware. The JavaFXPorts builds are freely available on this website for all developers.

Set Text property of asp:label in Javascript PROPER way

This one Works for me with asp label control.

 function changeEmaillbl() {

         if (document.getElementById('<%=rbAgency.ClientID%>').checked = true) {
             document.getElementById('<%=lblUsername.ClientID%>').innerHTML = 'Accredited No.:';

How to highlight text using javascript

Fast forward to 2019, Web API now has natively support for highlighting texts:

const selection = document.getSelection();
selection.setBaseAndExtent(anchorNode, anchorOffset, focusNode, focusOffset);

And you are good to go! anchorNode is the selection starting node, focusNode is the selection ending node. And, if they are text nodes, offset is the index of the starting and ending character in the respective nodes. Here is the documentation

They even have a live demo

Should switch statements always contain a default clause?

You should have a default to catch un-expected values coming in.

However, I disagree with the Adrian Smith that your error message for default should be something totally meaningless. There may be an un-handled case you didn't forsee (which is kind of the point) that your user will end up seeing and a message like "unreachable" is entirely pointless and doesn't help anyone in that situation.

Case in point, how many times have you had an utterly meaningless BSOD? Or a fatal exception @ 0x352FBB3C32342?

Vue is not defined

jsBin demo

  1. You missed the order, first goes:

<script src=""></script>

and then:

    var demo = new Vue({
        el: '#demo',
        data: {
            message: 'Hello Vue.js!'
  1. And type="JavaScript" should be type="text/javascript" (or rather nothing at all)

When to use 'raise NotImplementedError'?

As the documentation states [docs],

In user defined base classes, abstract methods should raise this exception when they require derived classes to override the method, or while the class is being developed to indicate that the real implementation still needs to be added.

Note that although the main stated use case this error is the indication of abstract methods that should be implemented on inherited classes, you can use it anyhow you'd like, like for indication of a TODO marker.

Is it possible to cherry-pick a commit from another git repository?

The answer, as given, is to use format-patch but since the question was how to cherry-pick from another folder, here is a piece of code to do just that:

$ git --git-dir=../<some_other_repo>/.git \
format-patch -k -1 --stdout <commit SHA> | \
git am -3 -k

(explanation from @cong ma)

The git format-patch command creates a patch from some_other_repo's commit specified by its SHA (-1 for one single commit alone). This patch is piped to git am, which applies the patch locally (-3 means trying the three-way merge if the patch fails to apply cleanly). Hope that explains.

Can we open pdf file using UIWebView on iOS?

UIWebviews can also load the .pdf using loadData method, if you acquire it as NSData:

[self.webView loadData:self.pdfData 

how to add script inside a php code?

  echo"<script language='javascript'>


How to send custom headers with requests in Swagger UI?

For those who use NSwag and need a custom header:

app.UseSwaggerUi3(typeof(Startup).GetTypeInfo().Assembly, settings =>
          settings.GeneratorSettings.IsAspNetCore = true;
          settings.GeneratorSettings.OperationProcessors.Add(new OperationSecurityScopeProcessor("custom-auth"));

              new SecurityDefinitionAppender("custom-auth", new SwaggerSecurityScheme
                    Type = SwaggerSecuritySchemeType.ApiKey,
                    Name = "header-name",
                    Description = "header description",
                    In = SwaggerSecurityApiKeyLocation.Header

Swagger UI will then include an Authorize button.

Cannot implicitly convert type 'string' to 'System.Threading.Tasks.Task<string>'

The listed return type of the method is Task<string>. You're trying to return a string. They are not the same, nor is there an implicit conversion from string to Task<string>, hence the error.

You're likely confusing this with an async method in which the return value is automatically wrapped in a Task by the compiler. Currently that method is not an async method. You almost certainly meant to do this:

private async Task<string> methodAsync() 
    await Task.Delay(10000);
    return "Hello";

There are two key changes. First, the method is marked as async, which means the return type is wrapped in a Task, making the method compile. Next, we don't want to do a blocking wait. As a general rule, when using the await model always avoid blocking waits when you can. Task.Delay is a task that will be completed after the specified number of milliseconds. By await-ing that task we are effectively performing a non-blocking wait for that time (in actuality the remainder of the method is a continuation of that task).

If you prefer a 4.0 way of doing it, without using await , you can do this:

private Task<string> methodAsync() 
    return Task.Delay(10000)
        .ContinueWith(t => "Hello");

The first version will compile down to something that is more or less like this, but it will have some extra boilerplate code in their for supporting error handling and other functionality of await we aren't leveraging here.

If your Thread.Sleep(10000) is really meant to just be a placeholder for some long running method, as opposed to just a way of waiting for a while, then you'll need to ensure that the work is done in another thread, instead of the current context. The easiest way of doing that is through Task.Run:

private Task<string> methodAsync() 
    return Task.Run(()=>
            return "Hello";

Or more likely:

private Task<string> methodAsync() 
    return Task.Run(()=>
            return SomeLongRunningMethodThatReturnsAString();

Checking whether a variable is an integer or not

I've had this problem before, if your type to use it in a if statement, and let's just say you wanted it to return true, you would enter this into a line, (The bottom line in all that is really needed to be looked at):

In [1]: test = 1

In [2]: test2 = 1.0

In [3]: type(test) == int
Out[3]: True

In [4]: type(test2) == int
Out[4]: False

In [5]: if type(x) == int is True:

You can do the same thing to check if it's a float, if it's true or false, and use to assign a name, (like x if you know what I mean.)

Git merge error "commit is not possible because you have unmerged files"

I've had a similar issue which boiled down to removing files under "unmerged paths"

Those files had to be removed using git rm

Align labels in form next to input


Nowadays you should definitely avoid using fixed widths. You could use flexbox or CSS grid to come up with a responsive solution. See the other answers.

One possible solution:

  • Give the labels display: inline-block;
  • Give them a fixed width
  • Align text to the right

That is:

label {
  display: inline-block;
  width: 140px;
  text-align: right;
<div class="block">
    <label>Simple label</label>
    <input type="text" />
<div class="block">
    <label>Label with more text</label>
    <input type="text" />
<div class="block">
    <input type="text" />


Best practice for localization and globalization of strings and labels

jQuery.i18n is a lightweight jQuery plugin for enabling internationalization in your web pages. It allows you to package custom resource strings in ‘.properties’ files, just like in Java Resource Bundles. It loads and parses resource bundles (.properties) based on provided language or language reported by browser.

to know more about this take a look at the How to internationalize your pages using JQuery?

Maven: Command to update repository after adding dependency to POM

mvn install (or mvn package) will always work.

You can use mvn compile to download compile time dependencies or mvn test for compile time and test dependencies but I prefer something that always works.

add scroll bar to table body

These solutions often have issues with the header columns aligning with the body columns, and may not work properly when resizing. I know you didn't want to use an additional library, but if you happen to be using jQuery, this one is really small. It supports fixed header, footer, column spanning (colspan), horizontal scrolling, resizing, and an optional number of rows to display before scrolling starts.

jQuery.scrollTableBody (GitHub)

As long as you have a table with proper <thead>, <tbody>, and (optional) <tfoot>, all you need to do is this:


How do I analyze a program's core dump file with GDB when it has command-line parameters?

You can use the core with GDB in many ways, but passing parameters which is to be passed to the executable to GDB is not the way to use the core file. This could also be the reason you got that error. You can use the core file in the following ways:

gdb <executable> <core-file> or gdb <executable> -c <core-file> or

gdb <executable>
(gdb) core <core-file>

When using the core file you don't have to pass arguments. The crash scenario is shown in GDB (checked with GDB version 7.1 on Ubuntu).

For example:

$ ./crash -p param1 -o param2
Segmentation fault (core dumped)
$ gdb ./crash core
GNU gdb (GDB) 7.1-ubuntu
Core was generated by `./crash -p param1 -o param2'. <<<<< See this line shows crash scenario
Program terminated with signal 11, Segmentation fault.
#0  __strlen_ia32 () at ../sysdeps/i386/i686/multiarch/../../i586/strlen.S:99
99    ../sysdeps/i386/i686/multiarch/../../i586/strlen.S: No such file or directory.
    in ../sysdeps/i386/i686/multiarch/../../i586/strlen.S

If you want to pass parameters to the executable to be debugged in GDB, use --args.

For example:

$ gdb --args ./crash -p param1 -o param2
GNU gdb (GDB) 7.1-ubuntu
(gdb) r
Starting program: /home/@@@@/crash -p param1 -o param2

Program received signal SIGSEGV, Segmentation fault.
__strlen_ia32 () at ../sysdeps/i386/i686/multiarch/../../i586/strlen.S:99
99    ../sysdeps/i386/i686/multiarch/../../i586/strlen.S: No such file or directory.
    in ../sysdeps/i386/i686/multiarch/../../i586/strlen.S

Man pages will be helpful to see other GDB options.

Why aren't variable-length arrays part of the C++ standard?

You could always use alloca() to allocate memory on the stack at runtime, if you wished:

void foo (int n)
    int *values = (int *)alloca(sizeof(int) * n);

Being allocated on the stack implies that it will automatically be freed when the stack unwinds.

Quick note: As mentioned in the Mac OS X man page for alloca(3), "The alloca() function is machine and compiler dependent; its use is dis-couraged." Just so you know.

What command means "do nothing" in a conditional in Bash?

The no-op command in shell is : (colon).

if [ "$a" -ge 10 ]
elif [ "$a" -le 5 ]
    echo "1"
    echo "2"

From the bash manual:

: (a colon)
Do nothing beyond expanding arguments and performing redirections. The return status is zero.

Java ArrayList Index

In order to store Strings in an dynamic array (add-method) you can't define it as an array of integers ( int[3] ). You should declare it like this:

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

System.out.println( alist.get(1) );

How do I parallelize a simple Python loop?

I found joblib is very useful with me. Please see following example:

from joblib import Parallel, delayed
def yourfunction(k):   
    print "Area of a circle with a radius ", k, " is:", s

element_run = Parallel(n_jobs=-1)(delayed(yourfunction)(k) for k in range(1,10))

n_jobs=-1: use all available cores

How to serve up images in Angular2?

If you do not like assets folder you can edit .angular-cli.json and add other folders you need.

  "assets": [

Could not obtain information about Windows NT group user

I had to connect to VPN for the publish script to successfully deploy to the DB.

Align two divs horizontally side by side center to the page using bootstrap css

This should do the trick:

<div class="container">
    <div class="row">
        <div class="col-xs-6">
        <div class="col-xs-6">

Have a read of the grid system section of the Bootstrap docs to familiarise yourself with how Bootstrap's grids work:

Recommended SQL database design for tags or tagging

If you are using a database that supports map-reduce, like couchdb, storing tags in a plain text field or list field is indeed the best way. Example:

tagcloud: {
  map: function(doc){ 
    for(tag in doc.tags){ 
  reduce: function(keys,values){
    return values.length

Running this with group=true will group the results by tag name, and even return a count of the number of times that tag was encountered. It's very similar to counting the occurrences of a word in text.

Create comma separated strings C#?

You can use the string.Join method to do something like string.Join(",", o.Number, o.Id, o.whatever, ...).

edit: As digEmAll said, string.Join is faster than StringBuilder. They use an external implementation for the string.Join.

Profiling code (of course run in release without debug symbols):

class Program
    static void Main(string[] args)
        Stopwatch sw = new Stopwatch();
        string r;
        int iter = 10000;

        string[] values = { "a", "b", "c", "d", "a little bit longer please", "one more time" };

        for (int i = 0; i < iter; i++)
            r = Program.StringJoin(",", values);
        Console.WriteLine("string.Join ({0} times): {1}ms", iter, sw.ElapsedMilliseconds);

        for (int i = 0; i < iter; i++)
            r = Program.StringBuilderAppend(",", values);
        Console.WriteLine("StringBuilder.Append ({0} times): {1}ms", iter, sw.ElapsedMilliseconds);

    static string StringJoin(string seperator, params string[] values)
        return string.Join(seperator, values);

    static string StringBuilderAppend(string seperator, params string[] values)
        StringBuilder builder = new StringBuilder();
        for (int i = 1; i < values.Length; i++)
        return builder.ToString();

string.Join took 2ms on my machine and StringBuilder.Append 5ms. So there is noteworthy difference. Thanks to digAmAll for the hint.

Android TextView padding between lines

You can use TextView.setLineSpacing(n,m) function.

Format a JavaScript string using placeholders and an object of substitutions?

Just use replace()

var values = {"%NAME%":"Mike","%AGE%":"26","%EVENT%":"20"};
var substitutedString = "My Name is %NAME% and my age is %AGE%.".replace("%NAME%", $values["%NAME%"]).replace("%AGE%", $values["%AGE%"]);

How to check Django version

Basically the same as bcoughlan's answer, but here it is as an executable command:

$ python -c "import django; print(django.get_version())"