Programs & Examples On #Applicative

In Haskell, Applicative functors are functors such that two functorial values can be combined into one, whilst the two values inside are combined via a functional application. An applicative functor has more structure than a functor but less than a monad.

How can I change the text inside my <span> with jQuery?

$('#abc span').html('A new text for the span.');

Preventing console window from closing on Visual Studio C/C++ Console application

Use Console.ReadLine() at the end of the program. This will keep the window open until you press the Enter key. See for details.

py2exe - generate single executable file

try c_x freeze it can create a good standalone

Submit form using a button outside the <form> tag

Similar to another solution here, with minor modification:

<form method="METHOD" id="FORMID">
   <!-- ...your inputs -->
<button type="submit" form="FORMID" value="Submit">Submit</button>

Subclipse svn:ignore

to ignore certain files or turn off ignoring you can use the eclipse preferences-->Team -->Ignored Resource. Check or uncheck the resources you want to be tracked.

Select Top and Last rows in a table (SQL server)

You must sort your data according your needs (es. in reverse order) and use select top query

Why is the Android emulator so slow? How can we speed up the Android emulator?

Firstly, you need to upgrade your RAM to atleast 8GB.

If you cannot upgrade your RAM, then try running the application on your Android Phone by connecting it via Data Cable and USB Debugging set as ON.

Also, you may use some other emulators like GenyMotion or Nox.

However, with the amount of RAM that you seem to be having, even other emulators may tend to be slow.

What is the correct format to use for Date/Time in an XML file

What does the DTD have to say?

If the XML file is for communicating with other existing software (e.g., SOAP), then check that software for what it expects.

If the XML file is for serialisation or communication with non-existing software (e.g., the one you're writing), you can define it. In which case, I'd suggest something that is both easy to parse in your language(s) of choice, and easy to read for humans. e.g., if your language (whether VB.NET or C#.NET or whatever) allows you to parse ISO dates (YYYY-MM-DD) easily, that's the one I'd suggest.

get the value of "onclick" with jQuery?

I'm not quite sure how to do this in jQuery... but this works:

var x = document.getElementById('google').attributes;
for (var i in x) {
 if (x[i].name == "onclick") alert(x[i];

but like Harshath said it would be better if you used event listeners, as removing and adding this function back into the onclick event may be troublesome.

Ignore outliers in ggplot2 boxplot

I had the same problem and precomputed the values for Q1, Q2, median, ymin, ymax using boxplot.stats:

# Load package and generate data
data <- rnorm(100)

# Compute boxplot statistics
stats <- boxplot.stats(data)$stats
df <- data.frame(x="label1", ymin=stats[1], lower=stats[2], middle=stats[3], 
                 upper=stats[4], ymax=stats[5])

# Create plot
p <- ggplot(df, aes(x=x, lower=lower, upper=upper, middle=middle, ymin=ymin, 
                    ymax=ymax)) + 

The result is a boxplot without outliers. enter image description here

Selenium wait until document is ready

This is a working Java version of the example you gave :

void waitForLoad(WebDriver driver) {
    new WebDriverWait(driver, 30).until((ExpectedCondition<Boolean>) wd ->
            ((JavascriptExecutor) wd).executeScript("return document.readyState").equals("complete"));

Example For c#:

public static void WaitForLoad(IWebDriver driver, int timeoutSec = 15)
    IJavaScriptExecutor js = (IJavaScriptExecutor)driver;
    WebDriverWait wait = new WebDriverWait(driver, new TimeSpan(0, 0, timeoutSec));
    wait.Until(wd => js.ExecuteScript("return document.readyState").ToString() == "complete");

Example for PHP:

final public function waitUntilDomReadyState(RemoteWebDriver $webDriver): void
    $webDriver->wait()->until(function () {
        return $webDriver->executeScript('return document.readyState') === 'complete';

Find control by name from Windows Forms controls

Use Control.ControlCollection.Find.

TextBox tbx = this.Controls.Find("textBox1", true).FirstOrDefault() as TextBox;
tbx.Text = "found!";

EDIT for asker:

Control[] tbxs = this.Controls.Find(txtbox_and_message[0,0], true);
if (tbxs != null && tbxs.Length > 0)
    tbxs[0].Text = "Found!";

How to know which is running in Jupyter notebook?

import sys

will give you the interpreter. You can select the interpreter you want when you create a new notebook. Make sure the path to your anaconda interpreter is added to your path (somewhere in your bashrc/bash_profile most likely).

For example I used to have the following line in my .bash_profile, that I added manually :

export PATH="$HOME/anaconda3/bin:$PATH"

EDIT: As mentioned in a comment, this is not the proper way to add anaconda to the path. Quoting Anaconda's doc, this should be done instead after install, using conda init:

Should I add Anaconda to the macOS or Linux PATH?

We do not recommend adding Anaconda to the PATH manually. During installation, you will be asked “Do you wish the installer to initialize Anaconda3 by running conda init?” We recommend “yes”. If you enter “no”, then conda will not modify your shell scripts at all. In order to initialize after the installation process is done, first run source <path to conda>/bin/activate and then run conda init

Find substring in the string in TWIG

Just searched for the docs, and found this:

Containment Operator: The in operator performs containment test. It returns true if the left operand is contained in the right:

{# returns true #}

{{ 1 in [1, 2, 3] }}

{{ 'cd' in 'abcde' }}

setting y-axis limit in matplotlib

If an axes (generated by code below the code shown in the question) is sharing the range with the first axes, make sure that you set the range after the last plot of that axes.

Batch - If, ElseIf, Else

batchfiles perform simple string substitution with variables. so, a simple

goto :language%language%
echo notfound

does this without any need for if.

How to split a string with any whitespace chars as delimiters

Something in the lines of


This groups all white spaces as a delimiter.

So if I have the string:

"Hello[space character][tab character]World"

This should yield the strings "Hello" and "World" and omit the empty space between the [space] and the [tab].

As VonC pointed out, the backslash should be escaped, because Java would first try to escape the string to a special character, and send that to be parsed. What you want, is the literal "\s", which means, you need to pass "\\s". It can get a bit confusing.

The \\s is equivalent to [ \\t\\n\\x0B\\f\\r].

phpinfo() - is there an easy way for seeing it?

From the CLI the best way is to use grep like:

php -i | grep libxml

C++ - how to find the length of an integer

The number of digits of an integer n in any base is trivially obtained by dividing until you're done:

unsigned int number_of_digits = 0;

do {
     n /= base;
} while (n);

How is a CSS "display: table-column" supposed to work?

The CSS table model is based on the HTML table model

A table is divided into ROWS, and each row contains one or more cells. Cells are children of ROWS, they are NEVER children of columns.

"display: table-column" does NOT provide a mechanism for making columnar layouts (e.g. newspaper pages with multiple columns, where content can flow from one column to the next).

Rather, "table-column" ONLY sets attributes that apply to corresponding cells within the rows of a table. E.g. "The background color of the first cell in each row is green" can be described.

The table itself is always structured the same way it is in HTML.

In HTML (observe that "td"s are inside "tr"s, NOT inside "col"s):

<table ..>
  <col .. />
  <col .. />
  <tr ..>
    <td ..></td>
    <td ..></td>
  <tr ..>
    <td ..></td>
    <td ..></td>

Corresponding HTML using CSS table properties (Note that the "column" divs do not contain any contents -- the standard does not allow for contents directly in columns):

.mytable {_x000D_
  display: table;_x000D_
.myrow {_x000D_
  display: table-row;_x000D_
.mycell {_x000D_
  display: table-cell;_x000D_
.column1 {_x000D_
  display: table-column;_x000D_
  background-color: green;_x000D_
.column2 {_x000D_
  display: table-column;_x000D_
<div class="mytable">_x000D_
  <div class="column1"></div>_x000D_
  <div class="column2"></div>_x000D_
  <div class="myrow">_x000D_
    <div class="mycell">contents of first cell in row 1</div>_x000D_
    <div class="mycell">contents of second cell in row 1</div>_x000D_
  <div class="myrow">_x000D_
    <div class="mycell">contents of first cell in row 2</div>_x000D_
    <div class="mycell">contents of second cell in row 2</div>_x000D_

OPTIONAL: both "rows" and "columns" can be styled by assigning multiple classes to each row and cell as follows. This approach gives maximum flexibility in specifying various sets of cells, or individual cells, to be styled:

//Useful css declarations, depending on what you want to affect, include:_x000D_
/* all cells (that have "class=mycell") */_x000D_
.mycell {_x000D_
/* class row1, wherever it is used */_x000D_
.row1 {_x000D_
/* all the cells of row1 (if you've put "class=mycell" on each cell) */_x000D_
.row1 .mycell {_x000D_
/* cell1 of row1 */_x000D_
.row1 .cell1 {_x000D_
/* cell1 of all rows */_x000D_
.cell1 {_x000D_
/* row1 inside class mytable (so can have different tables with different styles) */_x000D_
.mytable .row1 {_x000D_
/* all the cells of row1 of a mytable */_x000D_
.mytable .row1 .mycell {_x000D_
/* cell1 of row1 of a mytable */_x000D_
.mytable .row1 .cell1 {_x000D_
/* cell1 of all rows of a mytable */_x000D_
.mytable .cell1 {_x000D_
<div class="mytable">_x000D_
  <div class="column1"></div>_x000D_
  <div class="column2"></div>_x000D_
  <div class="myrow row1">_x000D_
    <div class="mycell cell1">contents of first cell in row 1</div>_x000D_
    <div class="mycell cell2">contents of second cell in row 1</div>_x000D_
  <div class="myrow row2">_x000D_
    <div class="mycell cell1">contents of first cell in row 2</div>_x000D_
    <div class="mycell cell2">contents of second cell in row 2</div>_x000D_

In today's flexible designs, which use <div> for multiple purposes, it is wise to put some class on each div, to help refer to it. Here, what used to be <tr> in HTML became class myrow, and <td> became class mycell. This convention is what makes the above CSS selectors useful.

PERFORMANCE NOTE: putting class names on each cell, and using the above multi-class selectors, is better performance than using selectors ending with *, such as .row1 * or even .row1 > *. The reason is that selectors are matched last first, so when matching elements are being sought, .row1 * first does *, which matches all elements, and then checks all the ancestors of each element, to find if any ancestor has class row1. This might be slow in a complex document on a slow device. .row1 > * is better, because only the immediate parent is examined. But it is much better still to immediately eliminate most elements, via .row1 .cell1. (.row1 > .cell1 is an even tighter spec, but it is the first step of the search that makes the biggest difference, so it usually isn't worth the clutter, and the extra thought process as to whether it will always be a direct child, of adding the child selector >.)

The key point to take away re performance is that the last item in a selector should be as specific as possible, and should never be *.

How do I check if a list is empty?

An empty list is itself considered false in true value testing (see python documentation):

a = []
if a:
     print "not empty"

@Daren Thomas

EDIT: Another point against testing the empty list as False: What about polymorphism? You shouldn't depend on a list being a list. It should just quack like a duck - how are you going to get your duckCollection to quack ''False'' when it has no elements?

Your duckCollection should implement __nonzero__ or __len__ so the if a: will work without problems.

How to export SQL Server database to MySQL?

if you have a MSSQL compatible SQL dump you can convert it to MySQL queries one by one using this online tool

Hope it saved your time

Emulator: ERROR: x86 emulation currently requires hardware acceleration

As per this response, the complete steps are:

1) Open SDK Manager (In Android Studio, go to Tools > Android > SDK Manager) and Download Intel x86 Emulator Accelerator (HAXM installer) if you haven't.

Intel x86 Emulator Accelerator (HAXM installer)

2) Now go to your SDK directory C:\users\%USERNAME%\AppData\Local\Android\sdk\extras\intel\Hardware_Accelerated_Execution_Manager\ and run the file named intelhaxm-android.exe.

In case you get an error like "Intel virtualization technology (vt,vt-x) is not enabled". Go to your BIOS settings and enable Hardware Virtualization.

3) Restart Android Studio and then try to start the AVD again.

It might take a minute or 2 to show the emulator window.

WPF Timer Like C# Timer

The timer has special functions.

  1. Call an asynchronous timer or synchronous timer.
  2. Change the time interval
  3. Ability to cancel and resume  

if you use StartAsync () or Start (), the thread does not block the user interface element

     namespace UITimer

        using thread = System.Threading;
        public class Timer

        public event Action<thread::SynchronizationContext> TaskAsyncTick;
        public event Action Tick;
        public event Action AsyncTick;
        public int Interval { get; set; } = 1;
        private bool canceled = false;
        private bool canceling = false;
        public async void Start()

                if (!canceled)
                    if (!canceling)
                        await Task.Delay(Interval);
                    canceled = false;

        public void Resume()
            canceling = false;
        public void Cancel()
            canceling = true;
        public async void StartAsyncTask(thread::SynchronizationContext 

                while (true)
                    if (!canceled)
                    if (!canceling)
                        await Task.Delay(Interval).ConfigureAwait(false);

                        canceled = false;

        public void StartAsync()
            thread::ThreadPool.QueueUserWorkItem((x) =>
                while (true)

                    if (!canceled)
                        if (!canceling)

                        canceled = false;

        public void StartAsync(thread::SynchronizationContext context)
            thread::ThreadPool.QueueUserWorkItem((x) =>

                    if (!canceled)
                        if (!canceling)
                            context.Post((xfail) => { AsyncTick.Invoke(); }, null);
                        canceled = false;
        public void Abort()
            canceled = true;


How to sleep for five seconds in a batch file/cmd

Can't we do waitfor /T 180?

waitfor /T 180 pause will result in "ERROR: Timed out waiting for 'pause'."

waitfor /T 180 pause >nul will sweep that "error" under the rug

The waitfor command should be there in Windows OS after Win95

In the past I've downloaded a executable named sleep that will work on the command line after you put it in your path.

For example: sleep shutdown -r -f /m \\yourmachine although shutdown now has -t option built in

How to round a floating point number up to a certain decimal place?

8.833333333339 (or 8.833333333333334, the result of 106.00/12) properly rounded to two decimal places is 8.83. Mathematically it sounds like what you want is a ceiling function. The one in Python's math module is named ceil:

import math

v = 8.8333333333333339
print(math.ceil(v*100)/100)  # -> 8.84

Respectively, the floor and ceiling functions generally map a real number to the largest previous or smallest following integer which has zero decimal places — so to use them for 2 decimal places the number is first multiplied by 102 (or 100) to shift the decimal point and is then divided by it afterwards to compensate.

If you don't want to use the math module for some reason, you can use this (minimally tested) implementation I just wrote:

def ceiling(x):
    n = int(x)
    return n if n-1 < x <= n else n+1

How all this relates to the linked Loan and payment calculator problem:

screenshot of loan calculator output

From the sample output it appears that they rounded up the monthly payment, which is what many call the effect of the ceiling function. This means that each month a little more than 1/12 of the total amount is being paid. That made the final payment a little smaller than usual — leaving a remaining unpaid balance of only 8.76.

It would have been equally valid to use normal rounding producing a monthly payment of 8.83 and a slightly higher final payment of 8.87. However, in the real world people generally don't like to have their payments go up, so rounding up each payment is the common practice — it also returns the money to the lender more quickly.

How can I create a unique constraint on my column (SQL Server 2008 R2)?

Here's another way through the GUI that does exactly what your script does even though it goes through Indexes (not Constraints) in the object explorer.

  1. Right click on "Indexes" and click "New Index..." (note: this is disabled if you have the table open in design view)

enter image description here

  1. Give new index a name ("U_Name"), check "Unique", and click "Add..."

enter image description here

  1. Select "Name" column in the next windown

enter image description here

  1. Click OK in both windows

How can I loop through a C++ map of maps?

use std::map< std::string, std::map<std::string, std::string> >::const_iterator when map is const.

How to persist a property of type List<String> in JPA?

When using the Hibernate implementation of JPA , I've found that simply declaring the type as an ArrayList instead of List allows hibernate to store the list of data.

Clearly this has a number of disadvantages compared to creating a list of Entity objects. No lazy loading, no ability to reference the entities in the list from other objects, perhaps more difficulty in constructing database queries. However when you are dealing with lists of fairly primitive types that you will always want to eagerly fetch along with the entity, then this approach seems fine to me.

public class Command implements Serializable {

    @GeneratedValue(strategy = GenerationType.AUTO)
    Long id;

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


How add spaces between Slick carousel item

Try to use pseudo classes like :first-child & :last-child to remove extra padding from first & last child.

Inspect the generated code of slick slider & try to remove padding on that.

Hope, it'll help!!!

Checking for #N/A in Excel cell from VBA code

First check for an error (N/A value) and then try the comparisation against cvErr(). You are comparing two different things, a value and an error. This may work, but not always. Simply casting the expression to an error may result in similar problems because it is not a real error only the value of an error which depends on the expression.

If IsError(ActiveWorkbook.Sheets("Publish").Range("G4").offset(offsetCount, 0).Value) Then
  If (ActiveWorkbook.Sheets("Publish").Range("G4").offset(offsetCount, 0).Value <> CVErr(xlErrNA)) Then
    'do something
  End If
End If

Percentage width in a RelativeLayout

Update 1

As pointed by @EmJiHash PercentRelativeLayout is deprecated in API level 26.0.0

Below quoting google comment:

This class was deprecated in API level 26.0.0. consider using ConstraintLayout and associated layouts instead. The following shows how to replicate the functionality of percentage layouts with a ConstraintLayout

Google introduced new API called

Then you can just specify percentage to take by view

Add compile dependency like

implementation '

in that, PercentRelativeLayout is what we can do a percentage wise layout


How to filter empty or NULL names in a QuerySet?

Firstly, the Django docs strongly recommend not using NULL values for string-based fields such as CharField or TextField. Read the documentation for the explanation:

Solution: You can also chain together methods on QuerySets, I think. Try this:


That should give you the set you're looking for.

What does a question mark represent in SQL queries?

It normally represents a parameter to be supplied by client.

ZIP Code (US Postal Code) validation

function isValidUSZip(sZip) {
   return /^\d{5}(-\d{4})?$/.test(sZip);

How to access a DOM element in React? What is the equilvalent of document.getElementById() in React

You can do that by specifying the ref

EDIT: In react v16.8.0 with function component, you can define a ref with useRef. Note that when you specify a ref on a function component, you need to use React.forwardRef on it to forward the ref to the DOM element of use useImperativeHandle to to expose certain functions from within the function component


const Child1 = React.forwardRef((props, ref) => {
    return <div ref={ref}>Child1</div> 

const Child2 = React.forwardRef((props, ref) => {
    const handleClick= () =>{};
    useImperativeHandle(ref,() => ({
    return <div>Child2</div> 
const App = () => {
    const child1 = useRef(null);
    const child2 = useRef(null);

    return (
           <Child1 ref={child1} />
           <Child1 ref={child1} />


In React 16.3+, use React.createRef() to create your ref:

class MyComponent extends React.Component {
  constructor(props) {
    this.myRef = React.createRef();
  render() {
    return <div ref={this.myRef} />;

In order to access the element, use:

const node = this.myRef.current;

DOC for using React.createRef()


However facebook advises against it because string refs have some issues, are considered legacy, and are likely to be removed in one of the future releases.

From the docs:

Legacy API: String Refs

If you worked with React before, you might be familiar with an older API where the ref attribute is a string, like "textInput", and the DOM node is accessed as this.refs.textInput. We advise against it because string refs have some issues, are considered legacy, and are likely to be removed in one of the future releases. If you're currently using this.refs.textInput to access refs, we recommend the callback pattern instead.

A recommended way for React 16.2 and earlier is to use the callback pattern:

<Progressbar completed={25} id="Progress1" ref={(input) => {this.Progress[0] = input }}/>

<h2 class="center"></h2>

<Progressbar completed={50} id="Progress2" ref={(input) => {this.Progress[1] = input }}/>

  <h2 class="center"></h2>

<Progressbar completed={75} id="Progress3" ref={(input) => {this.Progress[2] = input }}/>

DOC for using callback

Even older versions of react defined refs using string like below

<Progressbar completed={25} id="Progress1" ref="Progress1"/>

    <h2 class="center"></h2>

    <Progressbar completed={50} id="Progress2" ref="Progress2"/>

      <h2 class="center"></h2>

    <Progressbar completed={75} id="Progress3" ref="Progress3"/>

In order to get the element just do

var object = this.refs.Progress1;

Remember to use this inside an arrow function block like:

print = () => {
  var object = this.refs.Progress1;  

and so on...

How to reduce the image file size using PIL

The main image manager in PIL is PIL's Image module.

from PIL import Image
import math

foo ="path\\to\\image.jpg")
x, y = foo.size
x2, y2 = math.floor(x-50), math.floor(y-20)
foo = foo.resize((x2,y2),Image.ANTIALIAS)"path\\to\\save\\image_scaled.jpg",quality=95)

You can add optimize=True to the arguments of you want to decrease the size even more, but optimize only works for JPEG's and PNG's. For other image extensions, you could decrease the quality of the new saved image. You could change the size of the new image by just deleting a bit of code and defining the image size and you can only figure out how to do this if you look at the code carefully. I defined this size:

x, y = foo.size
x2, y2 = math.floor(x-50), math.floor(y-20)

just to show you what is (almost) normally done with horizontal images. For vertical images you might do:

x, y = foo.size
x2, y2 = math.floor(x-20), math.floor(y-50)

. Remember, you can still delete that bit of code and define a new size.

Should I use "camel case" or underscores in python?

for everything related to Python's style guide: i'd recommend you read PEP8.

To answer your question:

Function names should be lowercase, with words separated by underscores as necessary to improve readability.

How do I programmatically change file permissions?

Prior to Java 6, there is no support of file permission update at Java level. You have to implement your own native method or call Runtime.exec() to execute OS level command such as chmod.

Starting from Java 6, you can useFile.setReadable()/File.setWritable()/File.setExecutable() to set file permissions. But it doesn't simulate the POSIX file system which allows to set permission for different users. File.setXXX() only allows to set permission for owner and everyone else.

Starting from Java 7, POSIX file permission is introduced. You can set file permissions like what you have done on *nix systems. The syntax is :

File file = new File("file4.txt");

Set<PosixFilePermission> perms = new HashSet<>();

Files.setPosixFilePermissions(file.toPath(), perms);

This method can only be used on POSIX file system, this means you cannot call it on Windows system.

For details on file permission management, recommend you to read this post.

Is there an API to get bank transaction and bank balance?

Just a helpful hint, there is a company called who provides this data. They do charge for the API. Companies like use this API to gather bank and financial account data.

Also, checkout, they are a similar company and provide both authentication API for several banks and REST-based transaction fetching endpoints.

SQL Server equivalent to MySQL enum data type?

The best solution I've found in this is to create a lookup table with the possible values as a primary key, and create a foreign key to the lookup table.

Hide Spinner in Input Number - Firefox 29

In SASS/SCSS style, you can write like this:

input[type='number'] {
  -moz-appearance: textfield;/*For FireFox*/

  &::-webkit-inner-spin-button { /*For Webkits like Chrome and Safari*/
    -webkit-appearance: none;
    margin: 0;

Definitely this code style can use in PostCSS.

Is there a way for non-root processes to bind to "privileged" ports on Linux?

File capabilities are not ideal, because they can break after a package update.

The ideal solution, IMHO, should be an ability to create a shell with inheritable CAP_NET_BIND_SERVICE set.

Here's a somewhat convoluted way to do this:

sg $DAEMONUSER "capsh --keep=1 --uid=`id -u $DAEMONUSER` \
     --caps='cap_net_bind_service+pei' -- \

capsh utility can be found in libcap2-bin package in Debian/Ubuntu distributions. Here's what goes on:

  • sg changes effective group ID to that of the daemon user. This is necessary because capsh leaves GID unchanged and we definitely do not want it.
  • Sets bit 'keep capabilities on UID change'.
  • Changes UID to $DAEMONUSER
  • Drops all caps (at this moment all caps are still present because of --keep=1), except inheritable cap_net_bind_service
  • Executes your command ('--' is a separator)

The result is a process with specified user and group, and cap_net_bind_service privileges.

As an example, a line from ejabberd startup script:

sg $EJABBERDUSER "capsh --keep=1 --uid=`id -u $EJABBERDUSER` --caps='cap_net_bind_service+pei' -- $EJABBERD --noshell -detached"

How do I enable index downloads in Eclipse for Maven dependency search?

  1. In Eclipse, click on Windows > Preferences, and then choose Maven in the left side.
  2. Check the box "Download repository index updates on startup".
    • Optionally, check the boxes Download Artifact Sources and Download Artifact JavaDoc.
  3. Click OK. The warning won't appear anymore.
  4. Restart Eclipse.

Favorite Visual Studio keyboard shortcuts

Hmmm, nobody said F1 for help.

Could it be that Google is faster and better for getting at the information that you need.

Inline comments for Bash?

$(: ...) is a little less ugly, but still not good.

Regex to get the words after matching string

This might work out for you depending on which language you are using:

(?<=Object Name:).*

It's a positive lookbehind assertion. More information could be found here.

It won't work with JavaScript though. In your comment I read that you're using it for logstash. If you are using GROK parsing for logstash then it would work. You can verify it yourself here:

Enter image description here

How to test that no exception is thrown?

You can do it by using a @Rule and then call method reportMissingExceptionWithMessage as shown below: This is Scala code.

enter image description here

How to find the minimum value of a column in R?

df <- read.table(text = 
             "X  Y
             1  2  3
             2  4  5
             3  6  7
             4  8  9
             5 10 11",
             header = TRUE)

y_min <- min(df[,"Y"])

# Corresponding X value
x_val_associated <- df[df$Y == y_min, "X"]


First, you find the Y min using the min function on the "Y" column only. Notice the returned result is just an integer value. Then, to find the associated X value, you can subset the data.frame to only the rows where the minimum Y value is located and extract just the "X" column.

You now have two integer values for X and Y where Y is the min.

How to open a web server port on EC2 instance

You need to open TCP port 8787 in the ec2 Security Group. Also need to open the same port on the EC2 instance's firewall.

Cannot convert lambda expression to type 'string' because it is not a delegate type

My case it solved i was using

@Html.DropDownList(model => model.TypeId ...)  


@Html.DropDownListFor(model => model.TypeId ...) 

will solve it

How to convert int to char with leading zeros?

Not to High-Jack this question but the note needs to be made that you need to use (N)VARCHAR instead of (N)CHAR data-type.

RIGHT('000' + CAST(@number1 AS NCHAR(3)), 3 )

Above segment, will not produce the correct response from SQL 2005

RIGHT('000' + CAST(@number1 AS NVARCHAR(3)), 3 )

Above segment, will produce the desired response from SQL 2005

The the varchar will provide you with the desired prefix length on the fly. Where as the fixed length data type will require length designation and adjustments.

Doctrine and LIKE query

Actually you just need to tell doctrine who's your repository class, if you don't, doctrine uses default repo instead of yours.


SQL Current month/ year question

This should work for SQL Server:

year = DATEPART(yyyy, GETDATE())

Free FTP Library

I like Alex FTPS Client which is written by a Microsoft MVP name Alex Pilotti. It's a C# library you can use in Console apps, Windows Forms, PowerShell, ASP.NET (in any .NET language). If you have a multithreaded app you will have to configure the library to run syncronously, but overall a good client that will most likely get you what you need.

Can I append an array to 'formdata' in javascript?

This works for me when I sent file + text + array:

const uploadData = new FormData();
if (isArray(value)) {
  const k = `${key}[]`;
  uploadData.append(k, value);
} else {
  uploadData.append(key, value);

const headers = {
  'Content-Type': 'multipart/form-data',

How to input matrix (2D list) in Python?

The problem is on the initialization step.

for i in range (0,m):
  matrix[i] = columns

This code actually makes every row of your matrix refer to the same columns object. If any item in any column changes - every other column will change:

>>> for i in range (0,m):
...     matrix[i] = columns
>>> matrix
[[0, 0, 0], [0, 0, 0]]
>>> matrix[1][1] = 2
>>> matrix
[[0, 2, 0], [0, 2, 0]]

You can initialize your matrix in a nested loop, like this:

matrix = []
for i in range(0,m):
    for j in range(0,n):

or, in a one-liner by using list comprehension:

matrix = [[0 for j in range(n)] for i in range(m)]


matrix = [x[:] for x in [[0]*n]*m]

See also:

Hope that helps.

How do I make my ArrayList Thread-Safe? Another approach to problem in Java?

You can change from ArrayList to Vector type, in which every method is synchronized.

private Vector finishingOrder;
//Make a Vector to hold RaceCar objects to determine winners
finishingOrder = new Vector(numberOfRaceCars);

How to create a Java cron job

You can use TimerTask for Cronjobs.

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

     Timer t = new Timer();
     MyTask mTask = new MyTask();
     // This task is scheduled to run every 10 seconds

     t.scheduleAtFixedRate(mTask, 0, 10000);


class MyTask extends TimerTask{

   public MyTask(){
     //Some stuffs

   public void run() {
     System.out.println("Hi see you after 10 seconds");


Alternative You can also use ScheduledExecutorService.

What is the difference between `git merge` and `git merge --no-ff`?

The --no-ff flag causes the merge to always create a new commit object, even if the merge could be performed with a fast-forward. This avoids losing information about the historical existence of a feature branch and groups together all commits that together added the feature

VB.NET - If string contains "value1" or "value2"

You need this

If strMyString.Contains("Something") or strMyString.Contains("Something2") Then
End if

How to get the caller's method name in the called method?

I've come up with a slightly longer version that tries to build a full method name including module and class. (rev 9cccbf)

# Public Domain, i.e. feel free to copy/paste
# Considered a hack in Python 2

import inspect

def caller_name(skip=2):
    """Get a name of a caller in the format module.class.method

       `skip` specifies how many levels of stack to skip while getting caller
       name. skip=1 means "who calls me", skip=2 "who calls my caller" etc.

       An empty string is returned if skipped levels exceed stack height
    stack = inspect.stack()
    start = 0 + skip
    if len(stack) < start + 1:
      return ''
    parentframe = stack[start][0]    

    name = []
    module = inspect.getmodule(parentframe)
    # `modname` can be None when frame is executed directly in console
    # TODO(techtonik): consider using __main__
    if module:
    # detect classname
    if 'self' in parentframe.f_locals:
        # I don't know any way to detect call from the object method
        # XXX: there seems to be no way to detect static method call - it will
        #      be just a function call
    codename = parentframe.f_code.co_name
    if codename != '<module>':  # top level usually
        name.append( codename ) # function or a method

    ## Avoid circular refs and frame leaks
    del parentframe, stack

    return ".".join(name)

Reading a plain text file in Java

try {
  File f = new File("filename.txt");
  Scanner r = new Scanner(f);  
  while (r.hasNextLine()) {
    String data = r.nextLine();
} catch (FileNotFoundException ex) {
  JOptionPane.showMessageDialog("Error occurred");

How to include a quote in a raw Python string

Just to include new Python f String compatible functionality:

var_a = 10

f"""This is my quoted variable: "{var_a}". """

open link in iframe

Try this:

<iframe name="iframe1" src="target.html"></iframe>

<a href="link.html" target="iframe1">link</a>

The "target" attribute should open in the iframe.

what is the multicast doing on

I deactivated my "Arno's Iptables Firewall" for testing, and then the messages are gone

Laravel: Auth::user()->id trying to get a property of a non-object

In Laravel 5.6 I use

use Auth;
$user_id = Auth::user()->id;

as the other suggestion


seems to apply to older versions of Laravel 5.x and didn't work for me.

How abstraction and encapsulation differ?

my 2c

the purpose of encapsulation is to hide implementation details from the user of your class e.g. if you internally keep a std::list of items in your class and then decide that a std::vector would be more effective you can change this without the user caring. That said, the way you interact with the either stl container is thanks to abstraction, both the list and the vector can for instance be traversed in the same way using similar methods (iterators).

How can I switch to a tag/branch in hg?

Once you have cloned the repo, you have everything: you can then hg up branchname or hg up tagname to update your working copy.

UP: hg up is a shortcut of hg update, which also has hg checkout alias for people with git habits.

Only numbers. Input number in React

After reading all the answers but none really working for numbers only with copy and paste I came up with this solution.

  • parseInt solution: fails as parseInt("2a") is valid;
  • onKeyup sulution: fails on copy and paste, backspace;
  • key.which solution: will probably fail on copy and paste;
  • type="number" solution: fails on long numbers as javascript converts 40817810000000023511 into 40817810000000023500 because it is 53 bit language
    onChange={(event: any) => {
      if (isFinite( {
      // UPDATE YOUR STATE (i am using formik)

Converting a date string to a DateTime object using Joda Time library

Use DateTimeFormat:

DateTimeFormatter formatter = DateTimeFormat.forPattern("dd/MM/yyyy HH:mm:ss");
DateTime dt = formatter.parseDateTime(string);

Adding a library/JAR to an Eclipse Android project

Error parsing XML: unbound prefix

Resource '/playteddy/res' does not exist.

I got the above two errors and finally I solved it.

Right click your project -> properties -> java build path -> googleadmobadsdk (select and put it top), then you run and problem solved. It is solved my runtime error.

C# How to determine if a number is a multiple of another?

Use the modulus (%) operator:

6 % 3 == 0
7 % 3 == 1

LINQ Using Max() to select a single row

You can also do:

(from u in table
orderby u.Status descending
select u).Take(1);

How do I check if a string is valid JSON in Python?

Example Python script returns a boolean if a string is valid json:

import json

def is_json(myjson):
    json_object = json.loads(myjson)
  except ValueError as e:
    return False
  return True

Which prints:

print is_json("{}")                          #prints True
print is_json("{asdf}")                      #prints False
print is_json('{ "age":100}')                #prints True
print is_json("{'age':100 }")                #prints False
print is_json("{\"age\":100 }")              #prints True
print is_json('{"age":100 }')                #prints True
print is_json('{"foo":[5,6.8],"foo":"bar"}') #prints True

Convert a JSON string to a Python dictionary:

import json
mydict = json.loads('{"foo":"bar"}')
print(mydict['foo'])    #prints bar

mylist = json.loads("[5,6,7]")
[5, 6, 7]

Convert a python object to JSON string:

foo = {}
foo['gummy'] = 'bear'
print(json.dumps(foo))           #prints {"gummy": "bear"}

If you want access to low-level parsing, don't roll your own, use an existing library:

Great tutorial on python JSON module:

Is String JSON and show syntax errors and error messages:

sudo cpan JSON::XS
echo '{"foo":[5,6.8],"foo":"bar" bar}' > myjson.json
json_xs -t none < myjson.json


, or } expected while parsing object/hash, at character offset 28 (before "bar}
at /usr/local/bin/json_xs line 183, <STDIN> line 1.

json_xs is capable of syntax checking, parsing, prittifying, encoding, decoding and more:

React / JSX Dynamic Component Name

Edit: Other answers are better, see comments.

I solved the same problem this way:

render : function () {
  var componentToRender = 'component1Name';
  var componentLookup = {
    component1Name : (<Component1 />),
    component2Name : (<Component2 />),
  return (<div>

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

Another cause of this issue, surprisingly, is the deletion of the folder /var/log/mariadb This was my case after i deleted this log folder. After the creation, the error disappeared.

Javascript + Regex = Nothing to repeat error?

Well, in my case I had to test a Phone Number with the help of regex, and I was getting the same error,

Invalid regular expression: /+923[0-9]{2}-(?!1234567)(?!1111111)(?!7654321)[0-9]{7}/: Nothing to repeat'

So, what was the error in my case was that + operator after the / in the start of the regex. So enclosing the + operator with square brackets [+], and again sending the request, worked like a charm.

Following will work:


This answer may be helpful for those, who got the same type of error, but their chances of getting the error from this point of view, as mine! Cheers :)

Animate change of view background color on Android

best way is to use ValueAnimator and ColorUtils.blendARGB

 ValueAnimator valueAnimator = ValueAnimator.ofFloat(0.0f, 1.0f);
 valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        public void onAnimationUpdate(ValueAnimator valueAnimator) {

              float fractionAnim = (float) valueAnimator.getAnimatedValue();

                                    , Color.parseColor("#000000")
                                    , fractionAnim));

Android Volley - BasicNetwork.performRequest: Unexpected response code 400

public Map<String, String> getHeaders() throws AuthFailureError {
    HashMap<String, String> headers = new HashMap<String, String>();
    headers.put("Content-Type", "application/json; charset=utf-8");
    return headers;

You need to add Content-Type to the header.

Is there a standardized method to swap two variables in Python?

I know three ways to swap variables, but a, b = b, a is the simplest. There is

XOR (for integers)

x = x ^ y
y = y ^ x
x = x ^ y

Or concisely,

x ^= y
y ^= x
x ^= y

Temporary variable

w = x
x = y
y = w
del w

Tuple swap

x, y = y, x

postgres default timezone

Choose a timezone from:

SELECT * FROM pg_timezone_names;

And set as below given example:

ALTER DATABASE postgres SET timezone TO 'Europe/Berlin';

Use your DB name in place of postgres in above statement.

Multiple values in single-value context

Here's a generic helper function with assumption checking:

func assumeNoError(value interface{}, err error) interface{} {
    if err != nil {
        panic("error encountered when none assumed:" + err.Error())
    return value

Since this returns as an interface{}, you'll generally need to cast it back to your function's return type.

For example, the OP's example called Get(1), which returns (Item, error).

item := assumeNoError(Get(1)).(Item)

The trick that makes this possible: Multi-values returned from one function call can be passed in as multi-variable arguments to another function.

As a special case, if the return values of a function or method g are equal in number and individually assignable to the parameters of another function or method f, then the call f(g(parameters_of_g)) will invoke f after binding the return values of g to the parameters of f in order.

This answer borrows heavily from existing answers, but none had provided a simple, generic solution of this form.

React won't load local images

Here is how I did mine: if you use npx create-react-app to set up you react, you need to import the image from its folder in the Component where you want to use it. It's just the way you import other modules from their folders.

So, you need to write:

import myImage from './imageFolder/imageName'

Then in your JSX, you can have something like this: <image src = {myImage} />

See it in the screenshot below:

import image from its folder in a Component

How to convert an int to a hex string?

I wanted a random integer converted into a six-digit hex string with a # at the beginning. To get this I used

"#%6x" % random.randint(0xFFFFFF)

Node.js: How to send headers with form data using request module?

I've finally managed to do it. Answer in code snippet below:

var querystring = require('querystring');
var request = require('request');

var form = {
    username: 'usr',
    password: 'pwd',
    opaque: 'opaque',
    logintype: '1'

var formData = querystring.stringify(form);
var contentLength = formData.length;

    headers: {
      'Content-Length': contentLength,
      'Content-Type': 'application/x-www-form-urlencoded'
    uri: 'http://myUrl',
    body: formData,
    method: 'POST'
  }, function (err, res, body) {
    //it works!

How to concatenate characters in java?

You need a String object of some description to hold your array of concatenated chars, since the char type will hold only a single character. e.g.,

StringBuilder sb = new StringBuilder('a').append('b').append('c');

Can clearInterval() be called inside setInterval()?

Yes you can. You can even test it:

var i = 0;_x000D_
var timer = setInterval(function() {_x000D_
  if (i === 5) clearInterval(timer);_x000D_
  console.log('post-interval'); //this will still run after clearing_x000D_
}, 200);

In this example, this timer clears when i reaches 5.

Processing Symbol Files in Xcode

I know that this is not a technical solution but I had my iphone connected with the computer by cable and disconnecting the device from the computer and connecting it again (by cable again) worked for me as I could not solved it with the solutions that are provided before.

Android splash screen image sizes to fit all devices

Based off this answer from Lucas Cerro I calculated the dimensions using the ratios in the Android docs, using the baseline in the answer. I hope this helps someone else coming to this post!

  • xxxlarge (xxxhdpi): 1280x1920 (4.0x)
  • xxlarge (xxhdpi): 960x1440 (3.0x)
  • xlarge (xhdpi): 640x960 (2.0x)
  • large (hdpi): 480x800 (1.5x)
  • medium (mdpi): 320x480 (1.0x baseline)
  • small (ldpi): 240x320 (0.75x) 

How to enable PHP short tags?

sed -i "s/short_open_tag = .*/short_open_tag = On/" /etc/php/7.2/apache2/php.ini

That works on php7.2 on ubuntu 16, same answer as above by Bradley Flood, although the directory in which the config file is stored has changed.

Also you can change the version in the php string to match your currently installed version.

How do I copy the contents of one ArrayList into another?

There are no implicit copies made in java via the assignment operator. Variables contain a reference value (pointer) and when you use = you're only coping that value.

In order to preserve the contents of myTempObject you would need to make a copy of it.

This can be done by creating a new ArrayList using the constructor that takes another ArrayList:

ArrayList<Object> myObject = new ArrayList<Object>(myTempObject);

Edit: As Bohemian points out in the comments below, is this what you're asking? By doing the above, both ArrayLists (myTempObject and myObject) would contain references to the same objects. If you actually want a new list that contains new copies of the objects contained in myTempObject then you would need to make a copy of each individual object in the original ArrayList

Optional query string parameters in ASP.NET Web API

This issue has been fixed in the regular release of MVC4. Now you can do:

public string GetFindBooks(string author="", string title="", string isbn="", string  somethingelse="", DateTime? date= null) 
    // ...

and everything will work out of the box.

Javascript Get Element by Id and set the value

If myFunc(variable) is executed before textarea is rendered to page, you will get the null exception error.

    <script type="text/javascript">
        function myFunc(variable){
            var s = document.getElementById(variable);
            s.value = "new value";
        <textarea id="id1"></textarea>
//Error message: Cannot set property 'value' of null 

So, make sure your textarea does exist in the page, and then call myFunc, you can use window.onload or $(document).ready function. Hope it's helpful.

Parse JSON object with string and value only

You need to get a list of all the keys, loop over them and add them to your map as shown in the example below:

    String s = "{menu:{\"1\":\"sql\", \"2\":\"android\", \"3\":\"mvc\"}}";
    JSONObject jObject  = new JSONObject(s);
    JSONObject  menu = jObject.getJSONObject("menu");

    Map<String,String> map = new HashMap<String,String>();
    Iterator iter = menu.keys();
        String key = (String);
        String value = menu.getString(key);

What is the command to truncate a SQL Server log file?

Since the answer for me was buried in the comments. For SQL Server 2012 and beyond, you can use the following:

DBCC SHRINKFILE (Database_Log, 1)

html select scroll bar

Horizontal scrollbars in a HTML Select are not natively supported. However, here's a way to create the appearance of a horizontal scrollbar:

1. First create a css class

<style type="text/css">
   overflow: auto;
   width: 70px; /* adjust this width depending to amount of text to display */
   height: 80px; /* adjust height depending on number of options to display */
   border: 1px silver solid;
 .scrollable select{
   border: none;

2. Wrap the SELECT inside a DIV - also, explicitly set the size to the number of options.

<div class="scrollable">
<select size="6" multiple="multiple">
    <option value="1" selected>option 1 The Long Option</option>
    <option value="2">option 2</option>
    <option value="3">option 3</option>
    <option value="4">option 4</option>
    <option value="5">option 5 Another Longer than the Long Option ;)</option>
    <option value="6">option 6</option>

How to set an HTTP proxy in Python 2.7?

On my network just setting http_proxy didn't work for me. The following points were relevant.

1 Setting http_proxy for your user wont be preserved when you execute sudo - to preserve it, do:

sudo -E yourcommand

I got my install working by first installing cntlm local proxy. The instructions here is succinct :

Instead of student number, you'd put your domain username

2 To use the cntlm local proxy, exec:

pip install --proxy localhost:3128 pygments

How to define and use function inside Jenkins Pipeline config?

First off, you shouldn't add $ when you're outside of strings ($class in your first function being an exception), so it should be:

def doCopyMibArtefactsHere(projectName) {
    step ([
        $class: 'CopyArtifact',
        projectName: projectName,
        filter: '**/**.mib',
        fingerprintArtifacts: true, 
        flatten: true

def BuildAndCopyMibsHere(projectName, params) {
    build job: project, parameters: params

Now, as for your problem; the second function takes two arguments while you're only supplying one argument at the call. Either you have to supply two arguments at the call:

node { 
    stage('Prepare Mib'){
        BuildAndCopyMibsHere('project1', null)

... or you need to add a default value to the functions' second argument:

def BuildAndCopyMibsHere(projectName, params = null) {
    build job: project, parameters: params

Simple way to count character occurrences in a string

I believe the "one liner" that you expected to get is this:

"abdsd3$asda$asasdd$sadas".replaceAll( "[^$]*($)?", "$1" ).length();

Remember that the requirements are:

(instead of traversing manually all the string, or loop for indexOf)

and let me add: that at the heart of this question it sounds like "any loop" is not wanted and there is no requirement for speed. I believe the subtext of this question is coolness factor.

python list in sql query as parameter

I like bobince's answer:

placeholder= '?' # For SQLite. See DBAPI paramstyle.
placeholders= ', '.join(placeholder for unused in l)
query= 'SELECT name FROM students WHERE id IN (%s)' % placeholders
cursor.execute(query, l)

But I noticed this:

placeholders= ', '.join(placeholder for unused in l)

Can be replaced with:

placeholders= ', '.join(placeholder*len(l))

I find this more direct if less clever and less general. Here l is required to have a length (i.e. refer to an object that defines a __len__ method), which shouldn't be a problem. But placeholder must also be a single character. To support a multi-character placeholder use:

placeholders= ', '.join([placeholder]*len(l))

Why can't Python import Image from PIL?

I had the same error. Here was my workflow. I first installed PIL (not Pillow) using

pip install --no-index -f -U PIL

Then I found Pillow and installed it using

pip install Pillow

What fixed my issues was uninstalling both and reinstalling Pillow

pip uninstall PIL
pip uninstall Pillow
pip install Pillow

How to check if memcache or memcached is installed for PHP?

I combined, minified and extended (some more checks) the answers from @Bijay Rungta and @J.C. Inacio

    die("Memcache extension is not loaded");

if (!class_exists('Memcache')) 
    die('Memcache class not available');

$memcacheObj = new Memcache;
    die('Could not create memcache object');

if (!$memcacheObj->connect('localhost')) 
    die('Could not connect to memcache server');

// testdata to store in memcache
$testData = array(
    'the' => 'cake',
    'is' => 'a lie',

// set data (if not present)
$aData = $memcacheObj->get('data');
if (!$aData) 
    if(!$memcacheObj->set('data', $testData, 0, 300))
        die('Memcache could not set the data');

// try to fetch data
$aData = $memcacheObj->get('data');
if (!$aData) 
    die('Memcache is not responding with data');

if($aData !== $testData)
    die('Memcache is responding but with wrong data');

die('Memcache is working fine');

How to send an email using PHP?

For most projects, I use Swift mailer these days. It's a very flexible and elegant object-oriented approach to sending emails, created by the same people who gave us the popular Symfony framework and Twig template engine.

Basic usage :

require 'mail/swift_required.php';

$message = Swift_Message::newInstance()
    // The subject of your email
    ->setSubject('Jane Doe sends you a message')
    // The from address(es)
    ->setFrom(array('[email protected]' => 'Jane Doe'))
    // The to address(es)
    ->setTo(array('[email protected]' => 'Frank Stevens'))
    // Here, you put the content of your email
    ->setBody('<h3>New message</h3><p>Here goes the rest of my message</p>', 'text/html');

if (Swift_Mailer::newInstance(Swift_MailTransport::newInstance())->send($message)) {
    echo json_encode([
        "status" => "OK",
        "message" => 'Your message has been sent!'
} else {
    echo json_encode([
        "status" => "error",
        "message" => 'Oops! Something went wrong!'

See the official documentation for more info on how to use Swift mailer.

Declaring and initializing arrays in C

Why can't you initialize when you declare?

Which C compiler are you using? Does it support C99?

If it does support C99, you can declare the variable where you need it and initialize it when you declare it.

The only excuse I can think of for not doing that would be because you need to declare it but do an early exit before using it, so the initializer would be wasted. However, I suspect that any such code is not as cleanly organized as it should be and could be written so it was not a problem.

How can I strip first and last double quotes?

find the position of the first and the last " in your string

>>> s = '"" " " ""\\1" " "" ""'
>>> l = s.find('"')
>>> r = s.rfind('"')

>>> s[l+1:r]
'" " " ""\\1" " "" "'

Primefaces valueChangeListener or <p:ajax listener not firing for p:selectOneMenu

Another solution is to mix valueChangeListener, ajax and process:

<p:selectManyCheckbox id="employees" value="#{employees}" columns="1" layout="grid" valueChangeListener="#{mybean.fireSelection}"   >
    <f:selectItems var="employee" value="#{employeesSI}" />
    <p:ajax event="valueChange" immediate="true" process="@this"/>

Method in mybean is just :

public void fireSelection(ValueChangeEvent event) {
    log.debug("New: "+event.getNewValue()+", Old: "+event.getOldValue());

Like this, valueChangeEvent is very light !

PS: Works fine with PrimeFaces 5.0

Downloading a Google font and setting up an offline site that uses it

Found a step-by-step way to achieve this (for 1 font):
(as of Sep-9 2013)

  1. Choose your font at
  2. Add the desired one to your collection using "Add to collection" blue button
  3. Click the "See all styles" button near "Remove from collection" button and make sure that you have selected other styles you may also need such as 'bold'...
  4. Click the 'Use' tab button on bottom right of the page
  5. Click the download button on top with a down arrow image
  6. Click on "zip file" on the the popup message that appears
  7. Click "Close" button on the popup
  8. Slowly scroll the page until you see the 3 tabs "Standrd|@import|Javascript"
  9. Click "@import" tab
  10. Select and copy the url between 'url(' and ')'
  11. Copy it on address bar in a new tab and go there
  12. Do "File > Save page as..." and name it "desiredfontname.css" (replace accordingly)
  13. Decompress the fonts .zip file you downloaded (.ttf should be extracted)
  14. Go to "" and convert any .ttf extracted from zip to .woff
  15. Edit desiredfontname.css and replace any url within it [between 'url(' and ')'] with the corresponding converted .woff file you got on; path you write should be according to your server doc_root
  16. Save the file and move it at its final place and write the corresponding <link/> CSS tag to import these in your HTML page
  17. From now, refer to this font by its font-family name in your styles

That's it. Cause I had the same problem and the solution on top did not work for me.

curl: (6) Could not resolve host:; Name or service not known

Try nslookup to determine if there's a DNS issue. is your local network address and it looks like your system is using it as a DNS server. Is this your gateway/modem router as well? What happens when you try ping Can you browse to it on a Internet web browser?

How can I list the scheduled jobs running in my database?

I think you need the SCHEDULER_ADMIN role to see the dba_scheduler tables (however this may grant you too may rights)


Laravel Eloquent ORM Transactions

If you don't like anonymous functions:

try {
    // database queries here
} catch (\PDOException $e) {
    // Woopsy

Update: For laravel 4, the pdo object isn't public anymore so:

try {
    // database queries here
} catch (\PDOException $e) {
    // Woopsy

How to make a 3-level collapsing menu in Bootstrap?

Bootstrap 2.3.x and later supports the dropdown-submenu..

<ul class="dropdown-menu">
            <li><a href="#">Login</a></li>
            <li class="dropdown-submenu">
                <a tabindex="-1" href="#">More options</a>
                <ul class="dropdown-menu">
                    <li><a tabindex="-1" href="#">Second level</a></li>
                    <li><a href="#">Second level</a></li>
                    <li><a href="#">Second level</a></li>
            <li><a href="#">Logout</a></li>

Working demo on

Sql error on update : The UPDATE statement conflicted with the FOREIGN KEY constraint

It sometimes happens when you try to Insert/Update an entity while the foreign key that you are trying to Insert/Update actually does not exist. So, be sure that the foreign key exists and try again.

Remove all files except some from a directory

Trying it worked with:

rm -r !(Applications|"Virtualbox VMs"|Downloads|Documents|Desktop|Public)

but names with spaces are (as always) tough. Tried also with Virtualbox\ VMs instead the quotes. It deletes always that directory (Virtualbox VMs).

Get last 5 characters in a string

Old thread, but just only to say: to use the classic Left(), Right(), Mid() right now you don't need to write the full path (Microsoft.VisualBasic.Strings). You can use fast and easily like this:

Strings.Right(yourString, 5)

PHP - syntax error, unexpected T_CONSTANT_ENCAPSED_STRING

When you're working with strings in PHP you'll need to pay special attention to the formation, using " or '

$string = 'Hello, world!';
$string = "Hello, world!";

Both of these are valid, the following is not:

$string = "Hello, world';

You must also note that ' inside of a literal started with " will not end the string, and vice versa. So when you have a string which contains ', it is generally best practice to use double quotation marks.

$string = "It's ok here";

Escaping the string is also an option

$string = 'It\'s ok here too';

More information on this can be found within the documentation

How to concatenate and minify multiple CSS and JavaScript files with Grunt.js (0.3.x)

concat.js is being included in the concat task's source files public/js/*.js. You could have a task that removes concat.js (if the file exists) before concatenating again, pass an array to explicitly define which files you want to concatenate and their order, or change the structure of your project.

If doing the latter, you could put all your sources under ./src and your built files under ./dest

+-- css
¦   +-- 1.css
¦   +-- 2.css
¦   +-- 3.css
+-- js
    +-- 1.js
    +-- 2.js
    +-- 3.js

Then set up your concat task

concat: {
  js: {
    src: 'src/js/*.js',
    dest: 'dest/js/concat.js'
  css: {
    src: 'src/css/*.css',
    dest: 'dest/css/concat.css'

Your min task

min: {
  js: {
    src: 'dest/js/concat.js',
    dest: 'dest/js/concat.min.js'

The build-in min task uses UglifyJS, so you need a replacement. I found grunt-css to be pretty good. After installing it, load it into your grunt file


And then set it up

cssmin: {
    src: 'dest/css/concat.css',
    dest: 'dest/css/concat.min.css'

Notice that the usage is similar to the built-in min.

Change your default task to

grunt.registerTask('default', 'concat min cssmin');

Now, running grunt will produce the results you want.

+-- css
¦   +-- concat.css
¦   +-- concat.min.css
+-- js
    +-- concat.js
    +-- concat.min.js

How to determine if a decimal/double is an integer?

You can use String formatting for the double type. Here is an example:

double val = 58.6547;
String.Format("{0:0.##}", val);      
//Output: "58.65"

double val = 58.6;
String.Format("{0:0.##}", val);      
//Output: "58.6"

double val = 58.0;
String.Format("{0:0.##}", val);      
//Output: "58"

Let me know if this doesn't help.

Getting min and max Dates from a pandas dataframe


The built-in functions work well with Pandas Dataframes.

Disabling contextual LOB creation as createClob() method threw error

I hit this error when my web app was started in Linux by user logged in with insufficient access rights. This error

org.hibernate.engine.jdbc.internal.LobCreatorBuilder - HHH000424: Disabling contextual LOB creation as createClob() method threw error : java.lang.reflect.InvocationTargetException

usually preceded by other errors / exceptions, especially from your application server i.e for Tomcat:

org.apache.catalina.LifecycleException: Failed to initialize component ...


java.lang.UnsatisfiedLinkError: ... cannot open shared object file: No such file or directory


  1. Stop your web apps current instance.

  2. Login with super user or those with sufficient access rights i.e root

  3. Restart your web app or call previous function again.

How does Spring autowire by name when more than one matching bean is found?

You can use the @Qualifier annotation

From here

Fine-tuning annotation-based autowiring with qualifiers

Since autowiring by type may lead to multiple candidates, it is often necessary to have more control over the selection process. One way to accomplish this is with Spring's @Qualifier annotation. This allows for associating qualifier values with specific arguments, narrowing the set of type matches so that a specific bean is chosen for each argument. In the simplest case, this can be a plain descriptive value:

class Main {
    private Country country;
    public void setCountry(Country country) { = country;

This will use the UK add an id to USA bean and use that if you want the USA.

Changing plot scale by a factor in matplotlib

To set the range of the x-axis, you can use set_xlim(left, right), here are the docs


It looks like you want an identical plot, but only change the 'tick values', you can do that by getting the tick values and then just changing them to whatever you want. So for your need it would be like this:

ticks = your_plot.get_xticks()*10**9

How do you append an int to a string in C++?

cout << text << i;

The << operator for ostream returns a reference to the ostream, so you can just keep chaining the << operations. That is, the above is basically the same as:

cout << text;
cout << i;

Python Infinity - Any caveats?

So does C99.

The IEEE 754 floating point representation used by all modern processors has several special bit patterns reserved for positive infinity (sign=0, exp=~0, frac=0), negative infinity (sign=1, exp=~0, frac=0), and many NaN (Not a Number: exp=~0, frac?0).

All you need to worry about: some arithmetic may cause floating point exceptions/traps, but those aren't limited to only these "interesting" constants.

Spring @Value is not resolving to value from property file

I was using spring boot, and for me upgrading the version from 1.4.0.RELEASE to 1.5.6.RELEASE solved this issue.

How to find common elements from multiple vectors?

There might be a cleverer way to go about this, but


will do the job.

EDIT: More cleverly, and more conveniently if you have a lot of arguments:

Reduce(intersect, list(a,b,c))

Using cut command to remove multiple columns

You are able to cut all odd/even columns by using seq:

This would print all odd columns

echo 1,2,3,4,5,6,7,8,9,10 | cut -d, -f$(seq -s, 1 2 10)

To print all even columns you could use

echo 1,2,3,4,5,6,7,8,9,10 | cut -d, -f$(seq -s, 2 2 10)

By changing the second number of seq you can specify which columns to be printed.

If the specification which columns to print is more complex you could also use a "one-liner-if-clause" like

echo 1,2,3,4,5,6,7,8,9,10 | cut -d, -f$(for i in $(seq 1 10); do if [[ $i -lt 10 && $i -lt 5 ]];then echo -n $i,; else echo -n $i;fi;done)

This would print all columns from 1 to 5 - you can simply modify the conditions to create more complex conditions to specify weather a column shall be printed.

CSS: fixed to bottom and centered

I ran into a problem where the typical position: fixed and bottom: 0 didn't work. Discovered a neat functionality with position: sticky. Note it's "relatively" new so it won't with IE/Edge 15 and earlier.

Here's an example for w3schools.

<!DOCTYPE html>
div.sticky {
  position: sticky;
  bottom: 0;
  background-color: yellow;
  padding: 30px;
  font-size: 20px;

<p>Lorem ipsum dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas nisl est,  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dlerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dlerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dlerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dlerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas </p>

<div class="sticky">I will stick to the screen when you reach my scroll position</div>


How to access global variables

I would "inject" the starttime variable instead, otherwise you have a circular dependency between the packages.


var StartTime = time.Now()
func main() {
   otherPackage.StartTime = StartTime


var StartTime time.Time

Ctrl+click doesn't work in Eclipse Juno

The solution for me was to configure the build path to include the project itself.

  1. Right click on open project.
  2. highlight build path
  3. click on Configure build path…
  4. click on Source
  5. Click Add Folder… button.
  6. Put a check mark next to your project.
  7. Click OK.

If necessary, click the project menu and choose the ‘clean…’ option to rebuild.

Java - Change int to ascii

The most simple way is using type casting:

public char toChar(int c) {
    return (char)c;

Export table data from one SQL Server to another

For copying data from source to destination:

use <DestinationDatabase>
select * into <DestinationTable> from <SourceDataBase>.dbo.<SourceTable>

How to send a stacktrace to log4j?

this would be good log4j error/exception logging - readable by splunk/other logging/monitoring s/w. everything is form of key-value pair. log4j would get the stack trace from Exception obj e

    try {
    } catch (Exception e) {
        log.error("api_name={} method={} _message=\"error description.\" msg={}", 
                  new Object[]{"api_name", "method_name", e.getMessage(), e});

How to redirect to a route in laravel 5 by using href tag if I'm not using blade or any template?

In you app config file change the url to localhost/example/public

Then when you want to link to something

<a href="{{ url('page') }}">Some Text</a>

without blade

<a href="<?php echo url('page') ?>">Some Text</a>

Javascript to Select Multiple options

You can get access to the options array of a selected object by going document.getElementById("cars").options where 'cars' is the select object.

Once you have that you can call option[i].setAttribute('selected', 'selected'); to select an option.

I agree with every one else that you are better off doing this server side though.

moving committed (but not pushed) changes to a new branch after pull

Alternatively, right after you commit to the wrong branch, perform these steps:

  1. git log
  2. git diff {previous to last commit} {latest commit} > your_changes.patch
  3. git reset --hard origin/{your current branch}
  4. git checkout -b {new branch}
  5. git apply your_changes.patch

I can imagine that there is a simpler approach for steps one and two.

Array String Declaration

Declare the array size will solve your problem

 String[] title = {
            "Drug Addiction"
    String urlbase = "";
    String imgSel = "/logo.png";
    String[] mStrings = new String[title.length];

    for(int i=0;i<title.length;i++) {
        mStrings[i] = urlbase + title[i].toLowerCase() + imgSel;


IOError: [Errno 22] invalid mode ('r') or filename: 'c:\\Python27\test.txt'

\t is a tab character. Use a raw string instead:


or double the slashes:


or use forward slashes instead:


How to set margin with jquery?



I need to get all the cookies from the browser

You cannot. By design, for security purpose, you can access only the cookies set by your site. StackOverflow can't see the cookies set by UserVoice nor those set by Amazon.

ping: Temporary failure in name resolution

I've faced the exactly same problem but I've fixed it with another approache.

Using Ubuntu 18.04, first disable systemd-resolved service.

sudo systemctl disable systemd-resolved.service

Stop the service

sudo systemctl stop systemd-resolved.service

Then, remove the link to /run/systemd/resolve/stub-resolv.conf in /etc/resolv.conf

sudo rm /etc/resolv.conf

Add a manually created resolv.conf in /etc/

sudo vim /etc/resolv.conf

Add your prefered DNS server there


I've tested this with success.

Set bootstrap modal body height by percentage

The scss solution for Bootstrap 4.0

.modal { max-height: 100vh; .modal-dialog { .modal-content { .modal-body { max-height: calc(80vh - 140px); overflow-y: auto; } } } }

Make sure the .modal max-height is 100vh. Then for .modal-body use calc() function to calculate desired height. In above case we want to occupy 80vh of the viewport, reduced by the size of header + footer in pixels. This is around 140px together but you can measure it easily and apply your own custom values. For smaller/taller modal modify 80vh accordingly.

How to Set AllowOverride all

enter code hereif you are using linux you have to edit the


under the Documentroot . add the following code

`<Directory /var/www/>
  AllowOverride all
  Require all granted

then ,

`sudo service apache2 restart`

and you have to enable the apache mod rewrite

`sudo a2enmod rewrite`

How to set a Timer in Java?

Use this

long startTime = System.currentTimeMillis();
long elapsedTime = 0L.

while (elapsedTime < 2*60*1000) {
    //perform db poll/check
    elapsedTime = (new Date()).getTime() - startTime;

//Throw your exception

String to list in Python

Or for fun:

>>> ast.literal_eval('[%s]'%','.join(map(repr,s.split())))
['QH', 'QD', 'JC', 'KD', 'JS']


Is mongodb running?

this should work fine...

pgrep mongod

Spring MVC Missing URI template variable

This error may happen when mapping variables you defined in REST definition do not match with @PathVariable names.

Example: Suppose you defined in the REST definition

@GetMapping(value = "/{appId}", produces = "application/json", consumes = "application/json")

Then during the definition of the function, it should be

public ResponseEntity<List> getData(@PathVariable String appId)

This error may occur when you use any other variable other than defined in the REST controller definition with @PathVariable. Like, the below code will raise the error as ID is different than appId variable name:

public ResponseEntity<List> getData(@PathVariable String ID)

Counting number of lines, words, and characters in a text file

You could use regular expressions to count for you.

String subject = "First Line\n Second Line\nThird Line";  
Matcher wordM = Pattern.compile("\\b\\S+?\\b").matcher(subject); //matches a word
Matcher charM = Pattern.compile(".").matcher(subject); //matches a character
Matcher newLineM = Pattern.compile("\\r?\\n").matcher(subject); //matches a linebreak

int words=0,chars=0,newLines=1; //newLines is initially 1 because the first line has no corresponding linebreak

while(wordM.find()) words++;
while(charM.find()) chars++;
while(newLineM.find()) newLines++;

System.out.println("Words: "+words);
System.out.println("Chars: "+chars);
System.out.println("Lines: "+newLines);

How to Count Duplicates in List with LINQ

You can use "group by" + "orderby". See LINQ 101 for details

var list = new List<string> {"a", "b", "a", "c", "a", "b"};
var q = from x in list
        group x by x into g
        let count = g.Count()
        orderby count descending
        select new {Value = g.Key, Count = count};
foreach (var x in q)
    Console.WriteLine("Value: " + x.Value + " Count: " + x.Count);

In response to this post (now deleted):

If you have a list of some custom objects then you need to use custom comparer or group by specific property.

Also query can't display result. Show us complete code to get a better help.

Based on your latest update:

You have this line of code:

group xx by xx into g

Since xx is a custom object system doesn't know how to compare one item against another. As I already wrote, you need to guide compiler and provide some property that will be used in objects comparison or provide custom comparer. Here is an example:

Note that I use Foo.Name as a key - i.e. objects will be grouped based on value of Name property.

There is one catch - you treat 2 objects to be duplicate based on their names, but what about Id ? In my example I just take Id of the first object in a group. If your objects have different Ids it can be a problem.

//Using extension methods
var q = list.GroupBy(x => x.Name)
            .Select(x => new {Count = x.Count(), 
                              Name = x.Key, 
                              ID = x.First().ID})
            .OrderByDescending(x => x.Count);

//Using LINQ
var q = from x in list
        group x by x.Name into g
        let count = g.Count()
        orderby count descending
        select new {Name = g.Key, Count = count, ID = g.First().ID};

foreach (var x in q)
    Console.WriteLine("Count: " + x.Count + " Name: " + x.Name + " ID: " + x.ID);

How to dockerize maven project? and how many ways to accomplish it?

Create a Dockerfile
# Build stage

FROM maven:3.6.3-jdk-11-slim AS build

WORKDIR usr/src/app

COPY . ./

RUN mvn clean package

# Package stage

FROM openjdk:11-jre-slim

ARG JAR_NAME="project-name"

WORKDIR /usr/src/app


COPY --from=build /usr/src/app/target/${JAR_NAME}.jar ./app.jar

CMD ["java","-jar", "./app.jar"]

Launch Pycharm from command line (terminal)


It is now possible to create command line launcher automatically from JetBrains Toolbox. This is how you do it:

  1. Open up the toolbox window;
  2. Go to the gear icon in the upper right (the settings window for toolbox itself);
  3. Turn on Generate shell scripts;
  4. Fill the Shell script location textbox with the location where you want the launchers to reside. You have to do this manually it will not fill automatically at this time!

On Mac the location could be /usr/local/bin. For the novices, you can use any path inside the PATH variable or add a new path to the PATH variable in your bash profile. Use echo $PATH to see which paths are there.

Note! It did not work right away for me, I had to fiddle around a little before the scripts were generated. You can go to the gearbox of the IDEA (PyCharm for example) and see/change the launcher name. So for PyCharm, the default name is pycharm but you can change this to whatever you prefer.

Original answer

If you do not use the toolbox you can still use my original answer.

~~For some reason, the Create Command Line Launcher is not available anymore in 2019.1.~~ Because it is now part of JetBrains Toolbox

This is how you can create the script yourself:

If you already used the charm command before use type -a charm to find the script. Change the pycharm version in the file paths. Note that the numbering in the first variable RUN_PATH is different. You will have to look this up in the dir yourself.

RUN_PATH = u'/Users/boatfolder/Library/Application Support/JetBrains/Toolbox/apps/PyCharm-P/ch-0/191.6183.50/'
CONFIG_PATH = u'/Users/boatfolder/Library/Preferences/PyCharm2019.1'
SYSTEM_PATH = u'/Users/boatfolder/Library/Caches/PyCharm2019.1'

If you did not use the charm command before, you will have to create it.

Create the charm file somewhere like this: /usr/local/bin/charm

Then add this code (change version number to your version as explained above):

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import socket
import struct
import sys
import os
import time

# see com.intellij.idea.SocketLock for the server side of this interface

RUN_PATH = u'/Users/boatfolder/Library/Application Support/JetBrains/Toolbox/apps/PyCharm-P/ch-0/191.6183.50/'
CONFIG_PATH = u'/Users/boatfolder/Library/Preferences/PyCharm2019.1'
SYSTEM_PATH = u'/Users/boatfolder/Library/Caches/PyCharm2019.1'

def print_usage(cmd):
    print(('Usage:\n' +
           '  {0} -h | -? | --help\n' +
           '  {0} [project_dir]\n' +
           '  {0} [-l|--line line] [project_dir|--temp-project] file[:line]\n' +
           '  {0} diff <left> <right>\n' +
           '  {0} merge <local> <remote> [base] <merged>').format(cmd))

def process_args(argv):
    args = []

    skip_next = False
    for i, arg in enumerate(argv[1:]):
        if arg == '-h' or arg == '-?' or arg == '--help':
        elif i == 0 and (arg == 'diff' or arg == 'merge' or arg == '--temp-project'):
        elif arg == '-l' or arg == '--line':
            skip_next = True
        elif skip_next:
            skip_next = False
            path = arg
            if ':' in arg:
                file_path, line_number = arg.rsplit(':', 1)
                if line_number.isdigit():
                    path = file_path

    return args

def try_activate_instance(args):
    port_path = os.path.join(CONFIG_PATH, 'port')
    token_path = os.path.join(SYSTEM_PATH, 'token')
    if not (os.path.exists(port_path) and os.path.exists(token_path)):
        return False

        with open(port_path) as pf:
            port = int(
        with open(token_path) as tf:
            token =
    except (ValueError):
        return False

    s = socket.socket()
        s.connect(('', port))
    except (socket.error, IOError):
        return False

    found = False
    while True:
            path_len = struct.unpack('>h', s.recv(2))[0]
            path = s.recv(path_len).decode('utf-8')
            if os.path.abspath(path) == os.path.abspath(CONFIG_PATH):
                found = True
        except (socket.error, IOError):
            return False

    if found:
        cmd = 'activate ' + token + '\0' + os.getcwd() + '\0' + '\0'.join(args)
        if sys.version_info.major >= 3: cmd = cmd.encode('utf-8')
        encoded = struct.pack('>h', len(cmd)) + cmd
        time.sleep(0.5)  # don't close the socket immediately
        return True

    return False

def start_new_instance(args):
    if sys.platform == 'darwin':
        if len(args) > 0:
            args.insert(0, '--args')
        os.execvp('/usr/bin/open', ['-a', RUN_PATH] + args)
        bin_file = os.path.split(RUN_PATH)[1]
        os.execv(RUN_PATH, [bin_file] + args)

ide_args = process_args(sys.argv)
if not try_activate_instance(ide_args):

Pass props to parent component in React.js

Basically you use props to send information to and from Child and Parent.

Adding to all the wonderful answers, let me give a simple example that explains passing values from child to parent component in React


class App extends React.Component {
            this.handleFilterUpdate = this.handleFilterUpdate.bind(this);
      handleFilterUpdate(filterValue) {
                  name: filterValue
   render() {
      return (
            <Header change={this.handleFilterUpdate} name={} />


class Header extends React.Component {
                  names: 'jessy'
      Change(event) {

      // this.props.change(this.state.names);

   render() {
      return (
       <button onClick={this.Change.bind(this)}>click</button>



import React from 'react';
import ReactDOM from 'react-dom';

import App from './App.jsx';

ReactDOM.render(<App />, document.getElementById('app'));

Thats it , now you can pass values from your client to the server.

Take a look at the Change function in the Header.js

Change(event) {
      // this.props.change(this.state.names);

This is how you push values into the props from client to the server

Why so red? IntelliJ seems to think every declaration/method cannot be found/resolved

I had the same problem after changing JDK from 1.6 to 1.7 in my pom.xml and setting Maven 3 path + JDK project settings to 1.7.

What did it for me was => File -> Invalidate Caches and Restart

PS: problem occured again, so i just reimported the full project after deleting the .idea folder and now it works fine as usual :)

How to return a string value from a Bash function

You could have the function take a variable as the first arg and modify the variable with the string you want to return.

set -x
function pass_back_a_string() {
    eval "$1='foo bar rab oof'"

pass_back_a_string return_var
echo $return_var

Prints "foo bar rab oof".

Edit: added quoting in the appropriate place to allow whitespace in string to address @Luca Borrione's comment.

Edit: As a demonstration, see the following program. This is a general-purpose solution: it even allows you to receive a string into a local variable.

set -x
function pass_back_a_string() {
    eval "$1='foo bar rab oof'"

pass_back_a_string return_var
echo $return_var

function call_a_string_func() {
     local lvar=''
     pass_back_a_string lvar
     echo "lvar='$lvar' locally"

echo "lvar='$lvar' globally"

This prints:

+ return_var=
+ pass_back_a_string return_var
+ eval 'return_var='\''foo bar rab oof'\'''
++ return_var='foo bar rab oof'
+ echo foo bar rab oof
foo bar rab oof
+ call_a_string_func
+ local lvar=
+ pass_back_a_string lvar
+ eval 'lvar='\''foo bar rab oof'\'''
++ lvar='foo bar rab oof'
+ echo 'lvar='\''foo bar rab oof'\'' locally'
lvar='foo bar rab oof' locally
+ echo 'lvar='\'''\'' globally'
lvar='' globally

Edit: demonstrating that the original variable's value is available in the function, as was incorrectly criticized by @Xichen Li in a comment.

set -x
function pass_back_a_string() {
    eval "echo in pass_back_a_string, original $1 is \$$1"
    eval "$1='foo bar rab oof'"

return_var='original return_var'
pass_back_a_string return_var
echo $return_var

function call_a_string_func() {
     local lvar='original lvar'
     pass_back_a_string lvar
     echo "lvar='$lvar' locally"

echo "lvar='$lvar' globally"

This gives output:

+ return_var='original return_var'
+ pass_back_a_string return_var
+ eval 'echo in pass_back_a_string, original return_var is $return_var'
++ echo in pass_back_a_string, original return_var is original return_var
in pass_back_a_string, original return_var is original return_var
+ eval 'return_var='\''foo bar rab oof'\'''
++ return_var='foo bar rab oof'
+ echo foo bar rab oof
foo bar rab oof
+ call_a_string_func
+ local 'lvar=original lvar'
+ pass_back_a_string lvar
+ eval 'echo in pass_back_a_string, original lvar is $lvar'
++ echo in pass_back_a_string, original lvar is original lvar
in pass_back_a_string, original lvar is original lvar
+ eval 'lvar='\''foo bar rab oof'\'''
++ lvar='foo bar rab oof'
+ echo 'lvar='\''foo bar rab oof'\'' locally'
lvar='foo bar rab oof' locally
+ echo 'lvar='\'''\'' globally'
lvar='' globally

curl: (35) SSL connect error

curl 7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.19.1 Basic ECC zlib/1.2.3 libidn/1.18 libssh2/1.4.2

You are using a very old version of curl. My guess is that you run into the bug described 6 years ago. Fix is to update your curl.

How to master AngularJS?

Please keep an eye on the mailing list for problems/solutions discussed by community members.!forum/angular . It's been really useful to me.

How can I get the current date and time in UTC or GMT in Java?

this is my implementation:

public static String GetCurrentTimeStamp()
    Calendar cal=Calendar.getInstance();
    long offset = cal.getTimeZone().getOffset(System.currentTimeMillis());//if you want in UTC else remove it .
    return new java.sql.Timestamp(System.currentTimeMillis()+offset).toString();    

Does the 'mutable' keyword have any purpose other than allowing the variable to be modified by a const function?

Mutable is for marking specific attribute as modifiable from within const methods. That is its only purpose. Think carefully before using it, because your code will probably be cleaner and more readable if you change the design rather than use mutable.

So if the above madness isn't what mutable is for, what is it for? Here's the subtle case: mutable is for the case where an object is logically constant, but in practice needs to change. These cases are few and far between, but they exist.

Examples the author gives include caching and temporary debugging variables.

SSIS Convert Between Unicode and Non-Unicode Error

I experienced this condition when I had installed Oracle version 12 client 32 bit client connected to an Oracle 12 Server running on windows. Although both of Oracle-source and SqlServer-destination are NOT Unicode, I kept getting this message, as if the oracle columns were Unicode. I solved the problem inserting a data conversion box, and selecting type DT-STR (not unicode) for varchar2 fields and DT-WSTR (unicode) for numeric fields, then I've dropped the 'COPY OF' from the output field name. Note that I kept getting the error because I had connected the source box arrow with the conversion box BEFORE setting the convertion types. So I had to switch source box and this cleaned all the errors in the destination box.

How to encode the filename parameter of Content-Disposition header in HTTP?

I use the following code snippets for encoding (assuming fileName contains the filename and extension of the file, i.e.: test.txt):


if ( strpos ( $_SERVER [ 'HTTP_USER_AGENT' ], "MSIE" ) > 0 )
     header ( 'Content-Disposition: attachment; filename="' . rawurlencode ( $fileName ) . '"' );
     header( 'Content-Disposition: attachment; filename*=UTF-8\'\'' . rawurlencode ( $fileName ) );


fileName = request.getHeader ( "user-agent" ).contains ( "MSIE" ) ? URLEncoder.encode ( fileName, "utf-8") : MimeUtility.encodeWord ( fileName );
response.setHeader ( "Content-disposition", "attachment; filename=\"" + fileName + "\"");

Where is SQL Server Management Studio 2012?

I uninstalled all parts of SQL Server 2012 using Control Panel in Windows and then reinstalled (choosing "All Features"). Now it works!

Creating and Naming Worksheet in Excel VBA

Are you using an error handler? If you're ignoring errors and try to name a sheet the same as an existing sheet or a name with invalid characters, it could be just skipping over that line. See the CleanSheetName function here

for a list of invalid characters that you may want to check for.


Other things to try: Fully qualified references, throwing in a Doevents, code cleaning. This code qualifies your Sheets reference to ThisWorkbook (you can change it to ActiveWorkbook if that suits). It also adds a thousand DoEvents (stupid overkill, but if something's taking a while to get done, this will allow it to - you may only need one DoEvents if this actually fixes anything).

Dim WS As Worksheet
Dim i As Long

With ThisWorkbook
    Set WS = .Worksheets.Add(After:=.Sheets(.Sheets.Count))
End With

For i = 1 To 1000
Next i

WS.Name = txtSheetName.Value

Finally, whenever I have a goofy VBA problem that just doesn't make sense, I use Rob Bovey's CodeCleaner. It's an add-in that exports all of your modules to text files then re-imports them. You can do it manually too. This process cleans out any corrupted p-code that's hanging around.

SSH to Vagrant box in Windows?

  1. Install Git Bash (Comes with OpenSSH, as well as grep, find, perl, sed, etc.;)

    If you have Vagrant installed, open appwiz.cpl (AKA Add/Remove Programs) and Repair the Vagrant installation. This will make vagrant add itself to your git-bash path.

  2. Open Git Bash (Via the start menu)

  3. cd ~/vagrant/mybox to your vagrant box'es folder and vagrant ssh

Compiler error "archive for required library could not be read" - Spring Tool Suite

In case of VSCode, follow the below steps:

  1. Navigate to the respective folder that contains the corrupted jar
  2. Delete just the jar
  3. mvn clean
  4. mvn compile

That worked for me.

How to detect Safari, Chrome, IE, Firefox and Opera browser?

Simple, single line of JavaScript code will give you the name of browser:

function GetBrowser()
    return  navigator ? navigator.userAgent.toLowerCase() : "other";

"No backupset selected to be restored" SQL Server 2012

I got the same error message even though I backup and restore on the same single machine.

The issue was from here: when backup, i had 2 item in the destination box.

So the fix would be: make sure only 1 item in the 'destination' box. Remove all the others if there are.

New self vs. new static

In addition to others' answers :

static:: will be computed using runtime information.

That means you can't use static:: in a class property because properties values :

Must be able to be evaluated at compile time and must not depend on run-time information.

class Foo {
    public $name = static::class;


$Foo = new Foo;
echo $Foo->name; // Fatal error

Using self::

class Foo {
    public $name = self::class;

$Foo = new Foo;
echo $Foo->name; // Foo

Please note that the Fatal error comment in the code i made doesn't indicate where the error happened, the error happened earlier before the object was instantiated as @Grapestain mentioned in the comments

How do I format a number in Java?

Round numbers, yes. This is the main example source.

 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.

import java.util.*;
import java.text.*;

public class DecimalFormatDemo {

    static public void customFormat(String pattern, double value ) {
        DecimalFormat myFormatter = new DecimalFormat(pattern);
        String output = myFormatter.format(value);
        System.out.println(value + "  " + pattern + "  " + output);

    static public void localizedFormat(String pattern, double value,                                       Locale loc ) {
        NumberFormat nf = NumberFormat.getNumberInstance(loc);
        DecimalFormat df = (DecimalFormat)nf;
        String output = df.format(value);
        System.out.println(pattern + "  " + output + "  " + loc.toString());

    static public void main(String[] args) {

        customFormat("###,###.###", 123456.789);
        customFormat("###.##", 123456.789);
        customFormat("000000.000", 123.78);
        customFormat("$###,###.###", 12345.67);
        customFormat("\u00a5###,###.###", 12345.67);

        Locale currentLocale = new Locale("en", "US");

        DecimalFormatSymbols unusualSymbols = new DecimalFormatSymbols(currentLocale);
        String strange = "#,##0.###";
        DecimalFormat weirdFormatter = new DecimalFormat(strange, unusualSymbols);
        String bizarre = weirdFormatter.format(12345.678);

        Locale[] locales = {
            new Locale("en", "US"),
            new Locale("de", "DE"),
            new Locale("fr", "FR")

        for (int i = 0; i < locales.length; i++) {
            localizedFormat("###,###.###", 123456.789, locales[i]);

MySQL: selecting rows where a column is null

SELECT pid FROM planets WHERE userid IS NULL

Extract filename and extension in Bash

Mellen writes in a comment on a blog post:

Using Bash, there’s also ${file%.*} to get the filename without the extension and ${file##*.} to get the extension alone. That is,

echo "filename: ${file%.*}"
echo "extension: ${file##*.}"


filename: thisfile
extension: txt

MySQL "between" clause not inclusive?

select * from person where dob between '2011-01-01 00:00:00' and '2011-01-31 23:59:59'

SQL Server : How to test if a string has only digit characters

There is a system function called ISNUMERIC for SQL 2008 and up. An example:

FROM mTable

I did a couple of quick tests and also looked further into the docs:

ISNUMERIC returns 1 when the input expression evaluates to a valid numeric data type; otherwise it returns 0.

Which means it is fairly predictable for example

-9879210433 would pass but 987921-0433 does not. $9879210433 would pass but 9879210$433 does not.

So using this information you can weed out based on the list of valid currency symbols and + & - characters.

How can I install pip on Windows?

Working as of Feb 04 2014 :):

If you have tried installing pip through the Windows installer file from as suggested by @Colonel Panic, you might have installed the pip package manager successfully, but you might be unable to install any packages with pip. You might also have got the same SSL error as I got when I tried to install Beautiful Soup 4 if you look in the pip.log file:

Downloading/unpacking beautifulsoup4
  Getting page
  Could not fetch URL **connection error: [Errno 1] _ssl.c:504: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed**
  Will skip URL when looking for download links for beautifulsoup4

The problem is an issue with an old version of OpenSSL being incompatible with pip 1.3.1 and above versions. The easy workaround for now, is to install pip 1.2.1, which does not require SSL:

Installing Pip on Windows:

  1. Download pip 1.2.1 from
  2. Extract the pip-1.2.1.tar.gz file
  3. Change directory to the extracted folder: cd <path to extracted folder>/pip-1.2.1
  4. Run python install
  5. Now make sure C:\Python27\Scripts is in PATH because pip is installed in the C:\Python27\Scripts directory unlike C:\Python27\Lib\site-packages where Python packages are normally installed

Now try to install any package using pip.

For example, to install the requests package using pip, run this from cmd:

pip install requests

Whola! requests will be successfully installed and you will get a success message.

How to stop a function

This will end the function, and you can even customize the "Error" message:

import sys

def end():
    if condition:
        # the player wants to play again:
    elif not condition:
        sys.exit("The player doesn't want to play again") #Right here 

Failed to open the HAX device! HAX is not working and emulator runs in emulation mode emulator

I had the same problem. Just after enabling Internet Virtualization from BIOS. After that let the system boot and install HAXM once again. Now emulator will run faster than before and HAXM will work. Enjoy!!

How should the ViewModel close the form?

public partial class MyWindow: Window
    public ApplicationSelection()

      MyViewModel viewModel = new MyViewModel();

      DataContext = viewModel;

      viewModel.RequestClose += () => { Close(); };


public class MyViewModel

  //...Your code...

  public event Action RequestClose;

  public virtual void Close()
    if (RequestClose != null)

  public void SomeFunction()
     //...Do something...

Setting the User-Agent header for a WebClient request

You can check the WebClient documentation for a C# sample that adds a User-Agent to your WebClient and here for a sample for Windows Phone.

This is the sample for C#:

WebClient client = new WebClient ();

// Add a user agent header in case the 
// requested URI contains a query.

client.Headers.Add ("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; " + 
                                  "Windows NT 5.2; .NET CLR 1.0.3705;)");

This is a sample for Windows Phone (Silverlight):

request.Headers["UserAgent"] = "appname";
// OR
request.UserAgent = "appname";

How can you run a Java program without main method?

Applets from what I remember do not need a main method, though I am not sure they are technically a program.

how to use XPath with XDocument?

If you have XDocument it is easier to use LINQ-to-XML:

var document = XDocument.Load(fileName);
var name = document.Descendants(XName.Get("Name", @"")).First().Value;

If you are sure that XPath is the only solution you need:

using System.Xml.XPath;

var document = XDocument.Load(fileName);
var namespaceManager = new XmlNamespaceManager(new NameTable());
namespaceManager.AddNamespace("empty", "");
var name = document.XPathSelectElement("/empty:Report/empty:ReportInfo/empty:Name", namespaceManager).Value;

Execution failed for task ':app:compileDebugAidl': aidl is missing

I am working with sdk 23.1.0 and gradle 1.3.1. I created a new project edited nothing and got the aidl error. I went into my project gradle file and changed tool to 22.0.1 instead of 23.1.0 and it worked:

   compileSdkVersion 23
   buildToolsVersion "22.0.1" //"23.1.0"

getResources().getColor() is deprecated

I found that the useful getResources().getColor(R.color.color_name) is deprecated.

It is not deprecated in API Level 21, according to the documentation.

It is deprecated in the M Developer Preview. However, the replacement method (a two-parameter getColor() that takes the color resource ID and a Resources.Theme object) is only available in the M Developer Preview.

Hence, right now, continue using the single-parameter getColor() method. Later this year, consider using the two-parameter getColor() method on Android M devices, falling back to the deprecated single-parameter getColor() method on older devices.

Centering brand logo in Bootstrap Navbar

Try this:

.navbar {
    position: relative;
.brand {
    position: absolute;
    left: 50%;
    margin-left: -50px !important;  /* 50% of your logo width */
    display: block;

Centering your logo by 50% and minus half of your logo width so that it won't have problem when zooming in and out.

See fiddle

#pragma mark in Swift?

Pragma mark is a way to improve the readability of your code. The pragma comments would appear like tags on the Xcode jumpbar.

//MARK:  <Your comment goes here>

Example: In the code,

//MARK: Properties

// MARK: View Life cycle

//MARK: Helper methods

This is how it would appear in the Xcode jump bar.

enter image description here

How to tune Tomcat 5.5 JVM Memory settings without using the configuration program

Just to add to the previous comment, the documentation for the command line tool for updating the Tomcat service settings (if Tomcat is running as a service on Windows) is here. This tool updates the registry with the proper settings. So if you wanted to update the max memory setting for the Tomcat service you could run this (from the tomcat/bin directory), assuming the default service name of Tomcat5:

tomcat5 //US//Tomcat5 --JvmMx=512

C pointer to array/array of pointers disambiguation

The answer for the last two can also be deducted from the golden rule in C:

Declaration follows use.

int (*arr2)[8];

What happens if you dereference arr2? You get an array of 8 integers.

int *(arr3[8]);

What happens if you take an element from arr3? You get a pointer to an integer.

This also helps when dealing with pointers to functions. To take sigjuice's example:

float *(*x)(void )

What happens when you dereference x? You get a function that you can call with no arguments. What happens when you call it? It will return a pointer to a float.

Operator precedence is always tricky, though. However, using parentheses can actually also be confusing because declaration follows use. At least, to me, intuitively arr2 looks like an array of 8 pointers to ints, but it is actually the other way around. Just takes some getting used to. Reason enough to always add a comment to these declarations, if you ask me :)

edit: example

By the way, I just stumbled across the following situation: a function that has a static matrix and that uses pointer arithmetic to see if the row pointer is out of bounds. Example:

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

#define NUM_ELEM(ar) (sizeof(ar) / sizeof((ar)[0]))

int *
put_off(const int newrow[2])
    static int mymatrix[3][2];
    static int (*rowp)[2] = mymatrix;
    int (* const border)[] = mymatrix + NUM_ELEM(mymatrix);

    memcpy(rowp, newrow, sizeof(*rowp));
    rowp += 1;
    if (rowp == border) {
        rowp = mymatrix;

    return *rowp;

main(int argc, char *argv[])
    int i = 0;
    int row[2] = {0, 1};
    int *rout;

    for (i = 0; i &lt; 6; i++) {
        row[0] = i;
        row[1] += i;
        rout = put_off(row);
        printf("%d (%p): [%d, %d]\n", i, (void *) rout, rout[0], rout[1]);

    return 0;


0 (0x804a02c): [0, 0]
1 (0x804a034): [0, 0]
2 (0x804a024): [0, 1]
3 (0x804a02c): [1, 2]
4 (0x804a034): [2, 4]
5 (0x804a024): [3, 7]

Note that the value of border never changes, so the compiler can optimize that away. This is different from what you might initially want to use: const int (*border)[3]: that declares border as a pointer to an array of 3 integers that will not change value as long as the variable exists. However, that pointer may be pointed to any other such array at any time. We want that kind of behaviour for the argument, instead (because this function does not change any of those integers). Declaration follows use.

(p.s.: feel free to improve this sample!)

SOAP-ERROR: Parsing WSDL: Couldn't load from <URL>

As mentioned in earlier responses, this error can occur when interacting with a SOAP service over an HTTPS connection, and an issue is identified with the connection. The issue may be on the remote end (invalid cert) or on the client (in case of missing CA or PEM files). See for all possible SSL context settings. In my case, setting the path to my local certificate resolved the issue:

$context = ['ssl' => [
    'local_cert' => '/path/to/pem/file',

$params = [
    'soap_version' => SOAP_1_2, 
    'trace' => 1, 
    'exceptions' => 1, 
    'connection_timeout' => 180, 
    'stream_context' => stream_context_create($context), 
    'cache_wsdl' => WSDL_CACHE_NONE, // eliminate possible issue from cached wsdl

$client = new SoapClient('https://remoteservice/wsdl', $params);

Link to reload current page

<a href="">Refresh!</a>

Leave the href="" blank and it will refresh the page.
Also works if some info is passed using forms.

Is there any ASCII character for <br>?

& is a character; &amp; is a HTML character entity for that character.

<br> is an element. Elements don't get character entities.

In contrast to many answers here, \n or &#13; are not equivalent to <br>. The former denotes a line break in text documents. The latter is intended to denote a line break in HTML documents and is doing that by virtue of its default CSS:

br:before { content: "\A"; white-space: pre-line }

A textual line break can be rendered as an HTML line break or can be treated as whitespace, depending on the CSS white-space property.

Indent multiple lines quickly in vi

As well as the offered solutions, I like to do things a paragraph at a time with >}

Ubuntu apt-get unable to fetch packages

I recently had an issue with apt-get update getting stuck at 0%;

0% [Connecting to (2001:67c:1360:8001::21)]

Could be some sort of DNS issue on ipv6. I just add this as a workaround;

-o Acquire::ForceIPv4=true

Display array values in PHP

use implode(',', $array); for output as apple,banana,orange


foreach($array as $key => $value)
   echo $key." is ". $value;

Modifying location.hash without page scrolling

Adding this here because the more relevant questions have all been marked as duplicates pointing here…

My situation is simpler:

  • user clicks the link (a[href='#something'])
  • click handler does: e.preventDefault()
  • smoothscroll function: $("html,body").stop(true,true).animate({ "scrollTop": }, scrollspeed, "swing" );
  • then window.location = link;

This way, the scroll occurs, and there's no jump when the location is updated.

Java: How can I compile an entire directory structure of code ?

The already existing answers seem to only concern oneself with the *.java files themselves and not how to easily do it with library files that might be needed for the build.

A nice one-line situation which recursively gets all *.java files as well as includes *.jar files necessary for building is:

javac -cp ".:lib/*" -d bin $(find ./src/* | grep .java)

Here the bin file is the destination of class files, lib (and potentially the current working directory) contain the library files and all the java files in the src directory and beneath are compiled.

Volatile Vs Atomic

So what will happen if two threads attack a volatile primitive variable at same time?

Usually each one can increment the value. However sometime, both will update the value at the same time and instead of incrementing by 2 total, both thread increment by 1 and only 1 is added.

Does this mean that whosoever takes lock on it, that will be setting its value first.

There is no lock. That is what synchronized is for.

And in if meantime, some other thread comes up and read old value while first thread was changing its value, then doesn't new thread will read its old value?


What is the difference between Atomic and volatile keyword?

AtomicXxxx wraps a volatile so they are basically same, the difference is that it provides higher level operations such as CompareAndSwap which is used to implement increment.

AtomicXxxx also supports lazySet. This is like a volatile set, but doesn't stall the pipeline waiting for the write to complete. It can mean that if you read a value you just write you might see the old value, but you shouldn't be doing that anyway. The difference is that setting a volatile takes about 5 ns, bit lazySet takes about 0.5 ns.

How do I get the last word in each line with bash

there are many ways. as awk solutions shows, it's the clean solution

sed solution is to delete anything till the last space. So if there is no space at the end, it should work

sed 's/.* //g' <file>

you can avoid sed also and go for a while loop.

while read line
do [ -z "$line" ] && continue ;
echo $line|rev|cut -f1 -d' '|rev
done < file

it reads a line, reveres it, cuts the first (i.e. last in the original) and restores back

the same can be done in a pure bash way

while read line
do [ -z "$line" ] && continue ;
echo ${line##* }
done < file

it is called parameter expansion

dotnet ef not found in .NET Core 3

I was having this problem after I installed the dotnet-ef tool using Ansible with sudo escalated previllage on Ubuntu. I had to add become: no for the Playbook task, then the dotnet-ef tool became available to the current user.

  - name: install dotnet tool dotnet-ef
    command: dotnet tool install --global dotnet-ef --version {{dotnetef_version}}
    become: no

T-SQL: Opposite to string concatenation - how to split string into multiple records

Slight modification of the solution above so it works with variable-length delimiters.

create FUNCTION dbo.fn_Split2 (@sep nvarchar(10), @s nvarchar(4000))
    WITH Pieces(pn, start, stop) AS (
      SELECT 1, 1, CHARINDEX(@sep, @s)
      SELECT pn + 1, stop + (datalength(@sep)/2), CHARINDEX(@sep, @s, stop + (datalength(@sep)/2))
      FROM Pieces
      WHERE stop > 0
    SELECT pn,
      SUBSTRING(@s, start, CASE WHEN stop > 0 THEN stop-start ELSE 4000 END) AS s
    FROM Pieces

NB: I've used datalength() since len() reports incorrectly if there are trailing spaces.