Programs & Examples On #Htmltext

Text not wrapping inside a div element

This may help a small percentage of people still scratching their heads. Text copied from clipboard into VSCode may have an invisible hard space character preventing wrapping. Check it with HTML inspector

string with hard spaces

How to center the text in a JLabel?


If you cannot reconstruct the label for some reason, this is how you edit these properties of a pre-existent JLabel.

How to set Angular 4 background image?

You can use ngStyle to set background for a div

<div [ngStyle]="{background-image: 'url(./images/' + trls.img + ')'}"></div>

or you can also use built in background style:

<div [style.background-image]="'url(/images/' + trls.img + ')'"></div>

Append an empty row in dataframe using pandas

Append "empty" row to data frame and fill selected cells:

Generate empty data frame (no rows just columns a and b):

import pandas as pd    
col_names =  ["a","b"]
df  = pd.DataFrame(columns = col_names)

Append empty row at the end of the data frame:

df = df.append(pd.Series(), ignore_index = True)

Now fill the empty cell at the end (len(df)-1) of the data frame in column a:

df.loc[[len(df)-1],'a'] = 123


     a    b
0  123  NaN

And of course one can iterate over the rows and fill cells:

col_names =  ["a","b"]
df  = pd.DataFrame(columns = col_names)
for x in range(0,5):
    df = df.append(pd.Series(), ignore_index = True)
    df.loc[[len(df)-1],'a'] = 123


     a    b
0  123  NaN
1  123  NaN
2  123  NaN
3  123  NaN
4  123  NaN

How to get Bitmap from an Uri?

You can retrieve bitmap from uri like this

Bitmap bitmap = null;
try {
    bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), imageUri);
} catch (IOException e) {

Proxy setting for R

I had the same problem at my office and I solved it adding the proxy in the destination of the R shortcut; clik on right button of the R icon, preferences, and in the destination field add

"C:\Program Files\R\your_R_version\bin\Rgui.exe" http_proxy=http://user_id:passwod@your_proxy:your_port/

Be sure to put the directory where you have the R program installed. That works for me. Hope this help.

Unable to compile simple Java 10 / Java 11 project with Maven

Alright so for me nothing worked.
I was using spring boot with hibernate. The spring boot version was ~2.0.1 and I would keep get this error and null pointer exception upon compilation. The issue was with hibernate that needed a version bump. But after that I had some other issues that seemed like the annotation processor was not recognised so I decided to just bump spring from 2.0.1 to 2.1.7-release and everything worked as expected.

You still need to add the above plugin tough
Hope it helps!

Install a module using pip for specific python version

Use a version of pip installed against the Python instance you want to install new packages to.

In many distributions, there may be separate python2.6-pip and python2.7-pip packages, invoked with binary names such as pip-2.6 and pip-2.7. If pip is not packaged in your distribution for the desired target, you might look for a setuptools or easyinstall package, or use virtualenv (which will always include pip in a generated environment).

pip's website includes installation instructions, if you can't find anything within your distribution.

Changing upload_max_filesize on PHP

Since I just ran in to this problem on a shared host and was unable to add the values to my .htaccess file I thought I'd share my solution.

I made an ini file with the values in it. Simple as that:

Make a file called ".user.ini" and add your values

upload_max_filesize = 150M
post_max_size = 150M

Boom, problem solved.

error: invalid initialization of non-const reference of type ‘int&’ from an rvalue of type ‘int’

Non-const and const reference binding follow different rules

These are the rules of the C++ language:

  • an expression consisting of a literal number (12) is a "rvalue"
  • it is not permitted to create a non-const reference with a rvalue: int &ri = 12; is ill-formed
  • it is permitted to create a const reference with a rvalue: in this case, an unnamed object is created by the compiler; this object will persist as long as the reference itself exist.

You have to understand that these are C++ rules. They just are.

It is easy to invent a different language, say C++', with slightly different rules. In C++', it would be permitted to create a non-const reference with a rvalue. There is nothing inconsistent or impossible here.

But it would allow some risky code where the programmer might not get what he intended, and C++ designers rightly decided to avoid that risk.

'too many values to unpack', iterating over a dict. key=>string, value=>list

You want to use iteritems. This returns an iterator over the dictionary, which gives you a tuple(key, value)

>>> for field, values in fields.iteritems():
...     print field, values
first_names ['foo', 'bar']
last_name ['gravy', 'snowman']

Your problem was that you were looping over fields, which returns the keys of the dictionary.

>>> for field in fields:
...     print field

Running a cron every 30 seconds

Cron's granularity is in minutes and was not designed to wake up every x seconds to run something. Run your repeating task within a loop and it should do what you need:

#!/bin/env bash
while [ true ]; do
 sleep 30
 # do what you need to here

Python: Select subset from list based on index set

Use the built in function zip

property_asel = [a for (a, truth) in zip(property_a, good_objects) if truth]


Just looking at the new features of 2.7. There is now a function in the itertools module which is similar to the above code.

itertools.compress('ABCDEF', [1,0,1,0,1,1]) =>
  A, C, E, F

React - changing an uncontrolled input

When you first render your component, isn't set, so it evaluates to undefined or null, and you end up passing value={undefined} or value={null}to your input.

When ReactDOM checks to see if a field is controlled, it checks to see if value != null (note that it's !=, not !==), and since undefined == null in JavaScript, it decides that it's uncontrolled.

So, when onFieldChange() is called, is set to a string value, your input goes from being uncontrolled to being controlled.

If you do this.state = {name: ''} in your constructor, because '' != null, your input will have a value the whole time, and that message will go away.

Failed linking file resources

Run ./gradlew build -stacktrace in Android Studio terminal. It helps you to find a file that causes this error.

Show spinner GIF during an $http request in AngularJS?

create directive with this code:

$scope.$watch($http.pendingRequests, toggleLoader);

function toggleLoader(status){
  } else {

VBScript to send email without running Outlook

Yes. Blat or any other self contained SMTP mailer. Blat is a fairly full featured SMTP client that runs from command line

Blat is here

What's the purpose of SQL keyword "AS"?

When you aren't sure which syntax to choose, especially when there doesn't seem to be much to separate the choices, consult a book on heuristics. As far as I know, the only heuristics book for SQL is 'Joe Celko's SQL Programming Style':

A correlation name is more often called an alias, but I will be formal. In SQL-92, they can have an optional AS operator, and it should be used to make it clear that something is being given a new name. [p16]

This way, if your team doesn't like the convention, you can blame Celko -- I know I do ;)

UPDATE 1: IIRC for a long time, Oracle did not support the AS (preceding correlation name) keyword, which may explain why some old timers don't use it habitually.

UPDATE 2: the term 'correlation name', although used by the SQL Standard, is inappropriate. The underlying concept is that of a ‘range variable’.

UPDATE 3: I just re-read what Celko wrote and he is wrong: the table is not being renamed! I now think:

A correlation name is more often called an alias, but I will be formal. In Standard SQL they can have an optional AS keyword but it should not be used because it may give the impression that something is being renamed when it is not. In fact, it should be omitted to enforce the point that it is a range variable.

Convert LocalDate to LocalDateTime or java.sql.Timestamp

Since Joda is getting faded, someone might want to convert LocaltDate to LocalDateTime in Java 8. In Java 8 LocalDateTime it will give a way to create a LocalDateTime instance using a LocalDate and LocalTime. Check here.

public static LocalDateTime of(LocalDate date, LocalTime time)

Sample would be,

    // just to create a sample LocalDate
    DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyyMMdd");
    LocalDate ld = LocalDate.parse("20180306", dtf);

    // convert ld into a LocalDateTime
    // We need to specify the LocalTime component here as well, it can be any accepted value
    LocalDateTime ldt = LocalDateTime.of(ld, LocalTime.of(0,0)); // 2018-03-06T00:00

Just for reference, For getting the epoch seconds below can be used,

    ZoneId zoneId = ZoneId.systemDefault();
    long epoch = ldt.atZone(zoneId).toEpochSecond(); 

    // If you only care about UTC
    long epochUTC = ldt.toEpochSecond(ZoneOffset.UTC);

How can I convert string date to NSDate?

You can try this swift code

    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "dd/MM/yyyy"//same as strDate date formator
    dateFormatter.timeZone = TimeZone(abbreviation: "GMT+0:00")//Must used if you get one day less in conversion
    let convertedDateObject = strDate)

android button selector

Create custom_selector.xml in drawable folder

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="">
   <item android:drawable="@drawable/unselected" android:state_pressed="true" />
   <item android:drawable="@drawable/selected" />

Create selected.xml shape in drawable folder

<shape xmlns:android="" android:shape="rectangle" android:padding="90dp">
   <solid android:color="@color/selected"/>
   <padding />
   <stroke android:color="#000" android:width="1dp"/>
   <corners android:bottomRightRadius="15dp" android:bottomLeftRadius="15dp" android:topLeftRadius="15dp" android:topRightRadius="15dp"/>

Create unselected.xml shape in drawable folder

<shape xmlns:android="" android:shape="rectangle" android:padding="90dp">
   <solid android:color="@color/unselected"/>
   <padding />
   <stroke android:color="#000" android:width="1dp"/>
   <corners android:bottomRightRadius="15dp" android:bottomLeftRadius="15dp" android:topLeftRadius="15dp" android:topRightRadius="15dp"/>

Add following colors for selected/unselected state in color.xml of values folder

<color name="selected">#a8cf45</color>
<color name="unselected">#ff8cae3b</color>

you can check complete solution from here

Remove item from list based on condition

prods.Remove(prods.Find(x => x.ID == 1));

Bootstrap 3 .col-xs-offset-* doesn't work?

Its not working because col-xs-offset-* is mentioned out of the media query. if you want to use it, you have to mention all the offset (eg: class="col-xs-offset-3 col-sm-offset-2 col-md-offset-1 col-lg-offset-0")

But this is not right, they should mention col-xs-offset-* in the media query

R Apply() function on specific dataframe columns

Using an example data.frame and example function (just +1 to all values)

A <- function(x) x + 1
wifi <- data.frame(replicate(9,1:4))

#  X1 X2 X3 X4 X5 X6 X7 X8 X9
#1  1  1  1  1  1  1  1  1  1
#2  2  2  2  2  2  2  2  2  2
#3  3  3  3  3  3  3  3  3  3
#4  4  4  4  4  4  4  4  4  4

data.frame(wifi[1:3], apply(wifi[4:9],2, A) )
cbind(wifi[1:3], apply(wifi[4:9],2, A) )

#  X1 X2 X3 X4 X5 X6 X7 X8 X9
#1  1  1  1  2  2  2  2  2  2
#2  2  2  2  3  3  3  3  3  3
#3  3  3  3  4  4  4  4  4  4
#4  4  4  4  5  5  5  5  5  5

Or even:

data.frame(wifi[1:3], lapply(wifi[4:9], A) )
cbind(wifi[1:3], lapply(wifi[4:9], A) )

#  X1 X2 X3 X4 X5 X6 X7 X8 X9
#1  1  1  1  2  2  2  2  2  2
#2  2  2  2  3  3  3  3  3  3
#3  3  3  3  4  4  4  4  4  4
#4  4  4  4  5  5  5  5  5  5

How do I create an Excel chart that pulls data from multiple sheets?

2007 is more powerful with ribbon..:=) To add new series in chart do: Select Chart, then click Design in Chart Tools on the ribbon, On the Design ribbon, select "Select Data" in Data Group, Then you will see the button for Add to add new series.

Hope that will help.

How to access single elements in a table in R

?"[" pretty much covers the various ways of accessing elements of things.

Under usage it lists these:

x[i, j, ... , drop = TRUE]
x[[i, exact = TRUE]]
x[[i, j, ..., exact = TRUE]]
getElement(object, name)

x[i] <- value
x[i, j, ...] <- value
x[[i]] <- value
x$i <- value

The second item is sufficient for your purpose

Under Arguments it points out that with [ the arguments i and j can be numeric, character or logical

So these work:


As does this:


and keeping in mind a data frame is a list of vectors:


will also both work.

So that's a few things to be going on with. I suggest you type in the examples at the bottom of the help page one line at a time (yes, actually type the whole thing in one line at a time and see what they all do, you'll pick up stuff very quickly and the typing rather than copypasting is an important part of helping to commit it to memory.)

How to inspect Javascript Objects

This is blatant rip-off of Christian's excellent answer. I've just made it a bit more readable:

 * objectInspector digs through a Javascript object
 * to display all its properties
 * @param object - a Javascript object to inspect
 * @param result - a string of properties with datatypes
 * @return result - the concatenated description of all object properties
function objectInspector(object, result) {
    if (typeof object != "object")
        return "Invalid object";
    if (typeof result == "undefined")
        result = '';

    if (result.length > 50)
        return "[RECURSION TOO DEEP. ABORTING.]";

    var rows = [];
    for (var property in object) {
        var datatype = typeof object[property];

        var tempDescription = result+'"'+property+'"';
        tempDescription += ' ('+datatype+') => ';
        if (datatype == "object")
            tempDescription += 'object: '+objectInspector(object[property],result+'  ');
            tempDescription += object[property];

    }//Close for

    return rows.join(result+"\n");
}//End objectInspector

How do I get Month and Date of JavaScript in 2 digit format?

function GetDateAndTime(dt) {
  var arr = new Array(dt.getDate(), dt.getMonth(), dt.getFullYear(),dt.getHours(),dt.getMinutes(),dt.getSeconds());

  for(var i=0;i<arr.length;i++) {
    if(arr[i].toString().length == 1) arr[i] = "0" + arr[i];

  return arr[0] + "." + arr[1] + "." + arr[2] + " " + arr[3] + ":" + arr[4] + ":" + arr[5]; 

How to search a specific value in all tables (PostgreSQL)?

And if someone think it could help. Here is @Daniel Vérité's function, with another param that accept names of columns that can be used in search. This way it decrease the time of processing. At least in my test it reduced a lot.

    needle text,
    haystack_columns name[] default '{}',
    haystack_tables name[] default '{}',
    haystack_schema name[] default '{public}'
RETURNS table(schemaname text, tablename text, columnname text, rowctid text)
AS $$
  FOR schemaname,tablename,columnname IN
      SELECT c.table_schema,c.table_name,c.column_name
      FROM information_schema.columns c
      JOIN information_schema.tables t ON
        (t.table_name=c.table_name AND t.table_schema=c.table_schema)
      WHERE (c.table_name=ANY(haystack_tables) OR haystack_tables='{}')
        AND c.table_schema=ANY(haystack_schema)
        AND (c.column_name=ANY(haystack_columns) OR haystack_columns='{}')
        AND t.table_type='BASE TABLE'
    EXECUTE format('SELECT ctid FROM %I.%I WHERE cast(%I as text)=%L',
    ) INTO rowctid;
    IF rowctid is not null THEN
    END IF;
$$ language plpgsql;

Bellow is an example of usage of the search_function created above.

SELECT * FROM search_columns('86192700'
    , array(SELECT DISTINCT a.column_name::name FROM information_schema.columns AS a
            INNER JOIN information_schema.tables as b ON (b.table_catalog = a.table_catalog AND b.table_schema = a.table_schema AND b.table_name = a.table_name)
            a.column_name iLIKE '%cep%' 
            AND b.table_type = 'BASE TABLE'
            AND b.table_schema = 'public'

    , array(SELECT b.table_name::name FROM information_schema.columns AS a
            INNER JOIN information_schema.tables as b ON (b.table_catalog = a.table_catalog AND b.table_schema = a.table_schema AND b.table_name = a.table_name)
            a.column_name iLIKE '%cep%' 
            AND b.table_type = 'BASE TABLE'
            AND b.table_schema = 'public')

How to build a JSON array from mysql database

Just an update for Mysqli users :

$base= mysqli_connect($dbhost,  $dbuser, $dbpass, $dbbase);

if (mysqli_connect_errno()) 
  die('Could not connect: ' . mysql_error());

$return_arr = array();

if ($result = mysqli_query( $base, $sql )){
    while ($row = mysqli_fetch_assoc($result)) {
    $row_array['id'] = $row['id'];
    $row_array['col1'] = $row['col1'];
    $row_array['col2'] = $row['col2'];



echo json_encode($return_arr);

Less than or equal to

There is no => for if.
Use if %energy% GEQ %m2enc%

See if /? for some other details.

Node.js Mongoose.js string to ObjectId function

var mongoose = require('mongoose');
var _id = mongoose.mongo.ObjectId("4eb6e7e7e9b7f4194e000001");

Date Difference in php on days?

strtotime will convert your date string to a unix time stamp. (seconds since the unix epoch.

$ts1 = strtotime($date1);
$ts2 = strtotime($date2);

$seconds_diff = $ts2 - $ts1;

pandas: best way to select all columns whose names start with X

Now that pandas' indexes support string operations, arguably the simplest and best way to select columns beginning with 'foo' is just:

df.loc[:, df.columns.str.startswith('foo')]

Alternatively, you can filter column (or row) labels with df.filter(). To specify a regular expression to match the names beginning with foo.:

>>> df.filter(regex=r'^foo\.', axis=1)
   foo.aa  foo.bars  foo.fighters foo.manchu
0     1.0         0             0        2         NA
1     2.1         0             1        4          0
2     NaN         0           NaN        1          0
3     4.7         0             0        0          0
4     5.6         0             0        0          0
5     6.8         1             0        5          0

To select only the required rows (containing a 1) and the columns, you can use loc, selecting the columns using filter (or any other method) and the rows using any:

>>> df.loc[(df == 1).any(axis=1), df.filter(regex=r'^foo\.', axis=1).columns]
   foo.aa  foo.bars  foo.fighters foo.manchu
0     1.0         0             0        2         NA
1     2.1         0             1        4          0
2     NaN         0           NaN        1          0
5     6.8         1             0        5          0

HTML input field hint

If you mean like a text in the background, I'd say you use a label with the input field and position it on the input using CSS, of course. With JS, you fade out the label when the input receives values and fade it in when the input is empty. In this way, it is not possible for the user to submit the description, whether by accident or intent.

customize Android Facebook Login button

This is very simple. Add a button in the layout file like

   android:text="Login with facebook"

And in the onClick place the LoginManager's registercallback() method Becuse the this method automatically executes.

  public void fbLogin(View view)
    LoginManager.getInstance().logInWithReadPermissions(this, Arrays.asList("user_photos", "email", "public_profile", "user_posts" , "AccessToken"));
    LoginManager.getInstance().logInWithPublishPermissions(this, Arrays.asList("publish_actions"));
            new FacebookCallback<LoginResult>()
                public void onSuccess(LoginResult loginResult)
                    // App code

                public void onCancel()
                    // App code

                public void onError(FacebookException exception)
                    // App code

How to insert data into elasticsearch

I started off using curl, but since have migrated to use kibana. Here is some more information on the ELK stack from (E elastic search, K kibana):

With kibana your POST requests are a bit more simple:

    "field": "value",
    "id": 1,
    "account_id": 213,
    "name": "kimchy"

Removing first x characters from string?

Example to show last 3 digits of account number.

x = '1234567890'   
x.replace(x[:7], '')

o/p: '890'

How to enable PHP's openssl extension to install Composer?

I am using WAMP server. Actually its files showed that openssl is opened. But manually I went to the folder and edited php.ini. Then I found it has not opened openssl.I uncommented it and it worked after after WAMP restart.

Find what 2 numbers add to something and multiply to something

Here is how I would do that:

$sum = 5;
$product = 6;

$found = FALSE;
for ($a = 1; $a < $sum; $a++) {
  $b = $sum - $a;
  if ($a * $b == $product) {
    $found = TRUE;

if ($found) {
  echo "The answer is a = $a, b = $b.";
} else {
  echo "There is no answer where a and b are both integers.";

Basically, start at $a = 1 and $b = $sum - $a, step through it one at a time since we know then that $a + $b == $sum is always true, and multiply $a and $b to see if they equal $product. If they do, that's the answer.

See it working

Whether that is the most efficient method is very much debatable.

What does T&& (double ampersand) mean in C++11?

It declares an rvalue reference (standards proposal doc).

Here's an introduction to rvalue references.

Here's a fantastic in-depth look at rvalue references by one of Microsoft's standard library developers.

CAUTION: the linked article on MSDN ("Rvalue References: C++0x Features in VC10, Part 2") is a very clear introduction to Rvalue references, but makes statements about Rvalue references that were once true in the draft C++11 standard, but are not true for the final one! Specifically, it says at various points that rvalue references can bind to lvalues, which was once true, but was changed.(e.g. int x; int &&rrx = x; no longer compiles in GCC) – drewbarbs Jul 13 '14 at 16:12

The biggest difference between a C++03 reference (now called an lvalue reference in C++11) is that it can bind to an rvalue like a temporary without having to be const. Thus, this syntax is now legal:

T&& r = T();

rvalue references primarily provide for the following:

Move semantics. A move constructor and move assignment operator can now be defined that takes an rvalue reference instead of the usual const-lvalue reference. A move functions like a copy, except it is not obliged to keep the source unchanged; in fact, it usually modifies the source such that it no longer owns the moved resources. This is great for eliminating extraneous copies, especially in standard library implementations.

For example, a copy constructor might look like this:

foo(foo const& other)
    this->length = other.length;
    this->ptr = new int[other.length];
    copy(other.ptr, other.ptr + other.length, this->ptr);

If this constructor was passed a temporary, the copy would be unnecessary because we know the temporary will just be destroyed; why not make use of the resources the temporary already allocated? In C++03, there's no way to prevent the copy as we cannot determine we were passed a temporary. In C++11, we can overload a move constructor:

foo(foo&& other)
   this->length = other.length;
   this->ptr = other.ptr;
   other.length = 0;
   other.ptr = nullptr;

Notice the big difference here: the move constructor actually modifies its argument. This would effectively "move" the temporary into the object being constructed, thereby eliminating the unnecessary copy.

The move constructor would be used for temporaries and for non-const lvalue references that are explicitly converted to rvalue references using the std::move function (it just performs the conversion). The following code both invoke the move constructor for f1 and f2:

foo f1((foo())); // Move a temporary into f1; temporary becomes "empty"
foo f2 = std::move(f1); // Move f1 into f2; f1 is now "empty"

Perfect forwarding. rvalue references allow us to properly forward arguments for templated functions. Take for example this factory function:

template <typename T, typename A1>
std::unique_ptr<T> factory(A1& a1)
    return std::unique_ptr<T>(new T(a1));

If we called factory<foo>(5), the argument will be deduced to be int&, which will not bind to a literal 5, even if foo's constructor takes an int. Well, we could instead use A1 const&, but what if foo takes the constructor argument by non-const reference? To make a truly generic factory function, we would have to overload factory on A1& and on A1 const&. That might be fine if factory takes 1 parameter type, but each additional parameter type would multiply the necessary overload set by 2. That's very quickly unmaintainable.

rvalue references fix this problem by allowing the standard library to define a std::forward function that can properly forward lvalue/rvalue references. For more information about how std::forward works, see this excellent answer.

This enables us to define the factory function like this:

template <typename T, typename A1>
std::unique_ptr<T> factory(A1&& a1)
    return std::unique_ptr<T>(new T(std::forward<A1>(a1)));

Now the argument's rvalue/lvalue-ness is preserved when passed to T's constructor. That means that if factory is called with an rvalue, T's constructor is called with an rvalue. If factory is called with an lvalue, T's constructor is called with an lvalue. The improved factory function works because of one special rule:

When the function parameter type is of the form T&& where T is a template parameter, and the function argument is an lvalue of type A, the type A& is used for template argument deduction.

Thus, we can use factory like so:

auto p1 = factory<foo>(foo()); // calls foo(foo&&)
auto p2 = factory<foo>(*p1);   // calls foo(foo const&)

Important rvalue reference properties:

  • For overload resolution, lvalues prefer binding to lvalue references and rvalues prefer binding to rvalue references. Hence why temporaries prefer invoking a move constructor / move assignment operator over a copy constructor / assignment operator.
  • rvalue references will implicitly bind to rvalues and to temporaries that are the result of an implicit conversion. i.e. float f = 0f; int&& i = f; is well formed because float is implicitly convertible to int; the reference would be to a temporary that is the result of the conversion.
  • Named rvalue references are lvalues. Unnamed rvalue references are rvalues. This is important to understand why the std::move call is necessary in: foo&& r = foo(); foo f = std::move(r);

Why do you have to link the math library in C?

There's a thorough discussion of linking to external libraries in An Introduction to GCC - Linking with external libraries. If a library is a member of the standard libraries (like stdio), then you don't need to specify to the compiler (really the linker) to link them.

EDIT: After reading some of the other answers and comments, I think the libc.a reference and the libm reference that it links to both have a lot to say about why the two are separate.

Note that many of the functions in 'libm.a' (the math library) are defined in 'math.h' but are not present in libc.a. Some are, which may get confusing, but the rule of thumb is this--the C library contains those functions that ANSI dictates must exist, so that you don't need the -lm if you only use ANSI functions. In contrast, `libm.a' contains more functions and supports additional functionality such as the matherr call-back and compliance to several alternative standards of behavior in case of FP errors. See section libm, for more details.

error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)' -- Missing /var/run/mysqld/mysqld.sock

In My case two mysqld processes were running.. killed the optional processs by using pkill -9 mysqld

Rename multiple files by replacing a particular pattern in the filenames using a shell script

An example to help you get off the ground.

for f in *.jpg; do mv "$f" "$(echo "$f" | sed s/IMG/VACATION/)"; done

In this example, I am assuming that all your image files contain the string IMG and you want to replace IMG with VACATION.

The shell automatically evaluates *.jpg to all the matching files.

The second argument of mv (the new name of the file) is the output of the sed command that replaces IMG with VACATION.

If your filenames include whitespace pay careful attention to the "$f" notation. You need the double-quotes to preserve the whitespace.

Changing width property of a :before css selector using JQuery

I don't think there's a jQuery-way to directly access the pseudoclass' rules, but you could always append a new style element to the document's head like:

$('head').append('<style>.column:before{width:800px !important;}</style>');

See a live demo here

I also remember having seen a plugin that tackles this issue once but I couldn't find it on first googling unfortunately.

fs: how do I locate a parent folder?

Try this:

fs.readFile(__dirname + '/../../');

Note the forward slash at the beginning of the relative path.

Difference between if () { } and if () : endif;

I personally really hate the alternate syntax. One nice thing about the braces is that most IDEs, vim, etc all have bracket highlighting. In my text editor I can double click a brace and it will highlight the whole chunk so I can see where it ends and begins very easily.

I don't know of a single editor that can highlight endif, endforeach, etc.

Close Android Application

not a one-line-code solution, but pretty easy:

sub-class Activity, then override and add finish() to onPause() method

this way, activity will be gone once it enters background, therefore the app won't keep a stack of activities, you can finish() the current activity and the app is gone!

"Object doesn't support this property or method" error in IE11

Add the code snippet in JS file used in master page or used globally.

<script language="javascript">
if (typeof browseris !== 'undefined') { = false;

For more information refer blog:

Laravel 5 - redirect to HTTPS

I found out that this worked for me. First copy this code in the .htaccess file.

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{SERVER_PORT} !^443$
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

Converting a number with comma as decimal point to float

If you're using PHP5.3 or above, you can use numfmt_parse to do "a reversed number_format". If you're not, you stuck with replacing the occurrances with preg_replace/str_replace.

Copying text outside of Vim with set mouse=a enabled

Compilation settings that vim was compiled with, are part of the issue. vim --version shows these.

In OSX, the default vim has -clipboard But you need +clipboard

On osx you can and apparently generally should, use macvim. You can do brew cask install macvim That one has +clipboard.

Them you'll have two vims.

~$ ls -l /usr/bin/vim   <--- default vim
-rwxr-xr-x  1 root  wheel  1745984 15 Jul  2017 /usr/bin/vim

~$ ls -l /usr/local/bin/vim   <-- macvim, installed recently via that mentioned brew line. 
lrwxr-xr-x  1 apple  admin  42 16 May 23:32 /usr/local/bin/vim -> /Applications/

running vim will run macvim 'cos /usr/local/bin should be before /usr/bin in the path, though you can check with which vim.

running vim(to run macvim), is fine but you may want to map vi to macvim 'cos otherwise running vi stays at the default vim! You can rewrite or delete(with rm) and recreate the vi sym link, with ln. And to do that without an 'operation not permitted" error, you have to (temporarily) disable SIL. .

macvim has +clipboard as shown by vim --version

Here is a working ~/.vim/vimrc with just the required lines.

:set mouse=a
:map <leader>c "+y
:map <leader>v "+p

The default leader key is backslash.

I read a suggestion that one should use the leader key.. (certainly control has many keys already in use, so the suggestion was to not use control. I don't know if that applies to command key too, but anyhow).

With that mentioned mapping, \c will do "+y which will copy from the register known as +, to the clipboard. And \v will paste from the register known as +.

So that's a copy/paste that works between windows.

Another OS may require "* rather than "+

How to get domain URL and application name?

The following code might be useful for web application using JavaScript.

var newURL = window.location.protocol + "//"  + + "" + window.location.pathname;

newURL = newURL.substring(0,newURL.indexOf(""));

Disable activity slide-in animation when launching new activity?

FLAG_ACTIVITY_NO_ANIMATION may work, but wasn't doing the trick for me when combined with FLAG_ACTIVITY_CLEAR_TASK and FLAG_ACTIVITY_NEW_TASK. I'm apparently seeing the animation for creating a new task with a fresh activity stack as I navigate laterally to my other top-level views.

What did work here was calling "overridePendingTransition(0, 0);" either immediately after my startActivity() call or the onPause(). Both ways worked, but doing it after startActivity() gives me a little more control over when I want animations and when I don't.

Running two projects at once in Visual Studio

Max has the best solution for when you always want to start both projects, but you can also right click a project and choose menu Debug ? Start New Instance.

This is an option when you only occasionally need to start the second project or when you need to delay the start of the second project (maybe the server needs to get up and running before the client tries to connect, or something).

How to troubleshoot an "AttributeError: __exit__" in multiproccesing in Python?

The error also happens when trying to use the

with multiprocessing.Pool() as pool:
   # ...

with a Python version that is too old (like Python 2.X) and does not support using with together with multiprocessing pools.

(See this answer to another question for more details)

Valid content-type for XML, HTML and XHTML documents

HTML: text/html, full-stop.

XHTML: application/xhtml+xml, or only if following HTML compatbility guidelines, text/html. See the W3 Media Types Note.

XML: text/xml, application/xml (RFC 2376).

There are also many other media types based around XML, for example application/rss+xml or image/svg+xml. It's a safe bet that any unrecognised but registered ending in +xml is XML-based. See the IANA list for registered media types ending in +xml.

(For unregistered x- types, all bets are off, but you'd hope +xml would be respected.)

How do I change the font size of a UILabel in Swift?

I think the best way to do this - if keeping the same font that is already assigned to the UILabel would be:

(using Swift)

label.font = label.font.fontWithSize(20)

(using Swift 3)

label.font = label.font.withSize(20)

Ideally I would set this in the viewDidLayoutSubviews method, as it doesn't need to change every time the view appears.

Implicit function declarations in C

An implicitly declared function is one that has neither a prototype nor a definition, but is called somewhere in the code. Because of that, the compiler cannot verify that this is the intended usage of the function (whether the count and the type of the arguments match). Resolving the references to it is done after compilation, at link-time (as with all other global symbols), so technically it is not a problem to skip the prototype.

It is assumed that the programmer knows what he is doing and this is the premise under which the formal contract of providing a prototype is omitted.

Nasty bugs can happen if calling the function with arguments of a wrong type or count. The most likely manifestation of this is a corruption of the stack.

Nowadays this feature might seem as an obscure oddity, but in the old days it was a way to reduce the number of header files included, hence faster compilation.

How to set JAVA_HOME environment variable on Mac OS X 10.9?

I did it by putting

export JAVA_HOME=`/usr/libexec/java_home`

(backtics) in my .bashrc. See my comment on Adrian's answer.

Creating a left-arrow button (like UINavigationBar's "back" style) on a UIToolbar

Here's what I ended up doing after searching through all these solutions and others. It uses a stretchable png's extracted from the UIKit stock images. This way you can set the text to whatever you liek

// Generate the background images
UIImage *stretchableBackButton = [[UIImage imageNamed:@"UINavigationBarDefaultBack.png"] stretchableImageWithLeftCapWidth:14 topCapHeight:0];
UIImage *stretchableBackButtonPressed = [[UIImage imageNamed:@"UINavigationBarDefaultBackPressed.png"] stretchableImageWithLeftCapWidth:13 topCapHeight:0];
// Setup the UIButton
UIButton *backButton = [UIButton buttonWithType:UIButtonTypeCustom];
[backButton setBackgroundImage:stretchableBackButton forState:UIControlStateNormal];
[backButton setBackgroundImage:stretchableBackButtonPressed forState:UIControlStateSelected];
NSString *buttonTitle = NSLocalizedString(@"Back", @"Back");
[backButton setTitle:buttonTitle forState:UIControlStateNormal];
[backButton setTitle:buttonTitle forState:UIControlStateSelected];
backButton.titleEdgeInsets = UIEdgeInsetsMake(0, 5, 2, 1); // Tweak the text position
NSInteger width = ([backButton.titleLabel.text sizeWithFont:backButton.titleLabel.font].width + backButton.titleEdgeInsets.right +backButton.titleEdgeInsets.left);
[backButton setFrame:CGRectMake(0, 0, width, 29)];
backButton.titleLabel.font = [UIFont boldSystemFontOfSize:13.0f];
[backButton addTarget:self action:@selector(yourSelector:) forControlEvents:UIControlEventTouchDown];
// Now add the button as a custom UIBarButtonItem
UIBarButtonItem *backButtonItem = [[[UIBarButtonItem alloc] initWithCustomView:backButton] autorelease];
self.navigationItem.leftBarButtonItem = backButtonItem;

How do I change the color of radio buttons?

A radio button is a native element specific to each OS/browser. There is no way to change its color/style, unless you want to implement custom images or use a custom Javascript library which includes images (e.g. this - cached link)

Capturing multiple line output into a Bash variable

In addition to the answer given by @l0b0 I just had the situation where I needed to both keep any trailing newlines output by the script and check the script's return code. And the problem with l0b0's answer is that the 'echo x' was resetting $? back to zero... so I managed to come up with this very cunning solution:

RESULTX="$(./myscript; echo x$?)"

Copy multiple files with Ansible

Since Ansible 2.5 the with_* constructs are deprecated, and loop syntax should be used. A simple practical example:

- name: Copy CA files
    src: '{{item}}'
    dest: '/etc/pki/ca-trust/source/anchors'
    owner: root
    group: root
    mode: 0644
    - symantec-private.crt
    - verisignclass3g2.crt

Image Greyscale with CSS & re-color on mouse-over?

You can use a sprite which has both version—the colored and the monochrome—stored into it.

Escape string Python for MySQL

install sqlescapy package:

pip install sqlescapy

then you can escape variables in you raw query

from sqlescapy import sqlescape

query = """
    SELECT * FROM "bar_table" WHERE id='%s'
""" % sqlescape(user_input)

Node.js EACCES error when listening on most ports

This means the port is used somewhere else. so, you need to try another one or stop using the old port.

Fastest way to Remove Duplicate Value from a list<> by lambda

There is Distinct() method. it should works.

List<long> longs = new List<long> { 1, 2, 3, 4, 3, 2, 5 };
var distinctList = longs.Distinct().ToList();

How to convert HTML to PDF using iText

You can do it with the HTMLWorker class (deprecated) like this:

import com.itextpdf.text.html.simpleparser.HTMLWorker;
try {
    String k = "<html><body> This is my Project </body></html>";
    OutputStream file = new FileOutputStream(new File("C:\\Test.pdf"));
    Document document = new Document();
    PdfWriter.getInstance(document, file);;
    HTMLWorker htmlWorker = new HTMLWorker(document);
    htmlWorker.parse(new StringReader(k));
} catch (Exception e) {

or using the XMLWorker, (download from this jar) using this code:

import com.itextpdf.tool.xml.XMLWorkerHelper;
try {
    String k = "<html><body> This is my Project </body></html>";
    OutputStream file = new FileOutputStream(new File("C:\\Test.pdf"));
    Document document = new Document();
    PdfWriter writer = PdfWriter.getInstance(document, file);;
    InputStream is = new ByteArrayInputStream(k.getBytes());
    XMLWorkerHelper.getInstance().parseXHtml(writer, document, is);
} catch (Exception e) {

malloc for struct and pointer in C

You could actually do this in a single malloc by allocating for the Vector and the array at the same time. Eg:

struct Vector y = (struct Vector*)malloc(sizeof(struct Vector) + 10*sizeof(double));
y->x = (double*)((char*)y + sizeof(struct Vector));
y->n = 10;

This allocates Vector 'y', then makes y->x point to the extra allocated data immediate after the Vector struct (but in the same memory block).

If resizing the vector is required, you should do it with the two allocations as recommended. The internal y->x array would then be able to be resized while keeping the vector struct 'y' intact.

What's the difference between ISO 8601 and RFC 3339 Date Formats?

There are lots of differences between ISO 8601 and RFC 3339. Here is some examples to give you an idea:

2020-12-09T16:09:53+00:00 is a date time value that is compliant both both standards.

2020-12-09 16:09:53+00:00 uses a space to separate the date and time. This is allowed by RFC 3339 but not allowed by ISO 8601.

2020-12-09T16:09:53-00:00 has a negative sign in the time offset. This is allowed by RFC 3339 but not allowed by ISO 8601.

20201209T160953Z omits the hyphens. This is allowed by ISO 8601 but not allowed by RFC 3339.

ISO 8601 allows for things like ordinal dates such as 2020-344 which represents the 344th day of year 2020. RFC 3339 doesn't allow for that.

For your questions:

Is one just an extension?

No. As shown above each standard supports syntax variations not supported by the the other standard. So one syntax is not a superset or an extension of the other.

Should I use one over the other?

Of course this depends on your scenario. A safe general strategy is to generate date time strings that are valid by both standards.

Another good general strategy is to use an existing standard library for parsing/formatting date time strings and not write custom implementations unless you are addressing a genuinely custom scenario.

Do I really need to care that bad?

Well, that's up to you. Most regular developers who deal with date time strings should have a high level understanding but don't need to dive into the details.

Select first and last row from grouped data

using which.min and which.max :

library(dplyr, warn.conflicts = F)
df %>% 
  group_by(id) %>% 
  slice(c(which.min(stopSequence), which.max(stopSequence)))

#> # A tibble: 6 x 3
#> # Groups:   id [3]
#>      id stopId stopSequence
#>   <dbl> <fct>         <dbl>
#> 1     1 a                 1
#> 2     1 c                 3
#> 3     2 b                 1
#> 4     2 c                 4
#> 5     3 b                 1
#> 6     3 a                 3


It is also much faster than the current accepted answer because we find the min and max value by group, instead of sorting the whole stopSequence column.

# create a 100k times longer data frame
df2 <- bind_rows(replicate(1e5, df, F)) 
  mm =df2 %>% 
    group_by(id) %>% 
    slice(c(which.min(stopSequence), which.max(stopSequence))),
  jeremy = df2 %>%
    group_by(id) %>%
    arrange(stopSequence) %>%
    filter(row_number()==1 | row_number()==n()))
#> Warning: Some expressions had a GC in every iteration; so filtering is disabled.
#> # A tibble: 2 x 6
#>   expression      min   median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr> <bch:tm> <bch:tm>     <dbl> <bch:byt>    <dbl>
#> 1 mm           22.6ms     27ms     34.9     14.2MB     21.3
#> 2 jeremy      254.3ms    273ms      3.66    58.4MB     11.0

Is there an easy way to convert Android Application to IPad, IPhone

I'm not sure how helpful this answer is for your current application, but it may prove helpful for the next applications that you will be developing.

As iOS does not use Java like Android, your options are quite limited:

1) if your application is written mostly in C/C++ using JNI, you can write a wrapper and interface it with the iOS (i.e. provide callbacks from iOS to your JNI written function). There may be frameworks out there that help you do this easier, but there's still the problem of integrating the application and adapting it to the framework (and of course the fact that the application has to be written in C/C++).

2) rewrite it for iOS. I don't know whether there are any good companies that do this for you. Also, due to the variety of applications that can be written which can use different services and API, there may not be any software that can port it for you (I guess this kind of software is like a gold mine heh) or do a very good job at that.

3) I think that there are Java->C/C++ converters, but there won't help you at all when it comes to API differences. Also, you may find yourself struggling more to get the converted code working on any of the platforms rather than rewriting your application from scratch for iOS.

The problem depends quite a bit on the services and APIs your application is using. I haven't really look this up, but there may be some APIs that provide certain functionality in Android that iOS doesn't provide.

Using C/C++ and natively compiling it for the desired platform looks like the way to go for Android-iOS-Win7Mobile cross-platform development. This gets you somewhat of an application core/kernel which you can use to do the actual application logic.

As for the OS specific parts (APIs) that your application is using, you'll have to set up communication interfaces between them and your application's core.

Node.js Logging

Winston is strong choice for most of the developers. I have been using winston for long. Recently I used winston with with papertrail which takes the application logging to next level.

Here is a nice screenshot from their site.

enter image description here

How its useful

  • you can manage logs from different systems at one place. this can be very useful when you have two backend communicating and can see logs from both at on place.

  • Logs are live. you can see realtime logs of your production server.

  • Powerful search and filter

  • you can create alerts to send you email if it encounters specific text in log.

and you can find more

A simple configuration using winston,winston-express and winston-papertrail node modules.

import winston from 'winston';
import expressWinston from 'express-winston';
// Requiring `winston-papertrail` will expose
// `winston.transports.Papertrail`
// create winston transport for Papertrail
var winstonPapertrail = new winston.transports.Papertrail({
  host: '',
  port: XXXXX
  transports: [winstonPapertrail],
  meta: true, // optional: control whether you want to log the meta data about the request (default to true)
  msg: "HTTP {{req.method}} {{req.url}}", // optional: customize the default logging message. E.g. "{{res.statusCode}} {{req.method}} {{res.responseTime}}ms {{req.url}}"
  expressFormat: true, // Use the default Express/morgan request formatting. Enabling this will override any msg if true. Will only output colors with colorize set to true
  colorize: true, // Color the text and status code, using the Express/morgan color palette (text: gray, status: default green, 3XX cyan, 4XX yellow, 5XX red).
  ignoreRoute: function (req, res) { return false; } // optional: allows to skip some log messages based on request and/or response

Could not open ServletContext resource [/WEB-INF/applicationContext.xml]

Update: This will create a second context same as in applicationContext.xml

or you can add this code snippet to your web.xml


instead of


How to find length of digits in an integer?

n = 3566002020360505
count = 0
  count += 1
  n = n //10
print(f"The number of digits in the number are: {count}")

output: The number of digits in the number are: 16

What is the default initialization of an array in Java?

Everything in a Java program not explicitly set to something by the programmer, is initialized to a zero value.

  • For references (anything that holds an object) that is null.
  • For int/short/byte/long that is a 0.
  • For float/double that is a 0.0
  • For booleans that is a false.
  • For char that is the null character '\u0000' (whose decimal equivalent is 0).

When you create an array of something, all entries are also zeroed. So your array contains five zeros right after it is created by new.

Note (based on comments): The Java Virtual Machine is not required to zero out the underlying memory when allocating local variables (this allows efficient stack operations if needed) so to avoid random values the Java Language Specification requires local variables to be initialized.

Swift 3 URLSession.shared() Ambiguous reference to member 'dataTask(with:completionHandler:) error (bug)

You have init'd myRequest as NSMutableURLRequest, you need this:

var URLRequest

Swift is ditching both the NSMutable... thing. Just use var for the new classes.

How to Delete Session Cookie?

This needs to be done on the server-side, where the cookie was issued.

MySQL case sensitive query

To improve James' excellent answer:

It's better to put BINARY in front of the constant instead:

SELECT * FROM `table` WHERE `column` = BINARY 'value'

Putting BINARY in front of column will prevent the use of any index on that column.

HTTP GET request in JavaScript?

I'm not familiar with Mac OS Dashcode Widgets, but if they let you use JavaScript libraries and support XMLHttpRequests, I'd use jQuery and do something like this:

var page_content;
$.get( "somepage.php", function(data){
    page_content = data;

Calculate Age in MySQL (InnoDb)

Simply do

SELECT birthdate, (YEAR(CURDATE())-YEAR(birthdate)) AS age FROM `member` 

birthdate is field name that keep birthdate name take CURDATE() turn to year by YEAR() command minus with YEAR() from the birthdate field

How to deploy a Java Web Application (.war) on tomcat?

As others pointed out, the most straightforward way to deploy a WAR is to copy it to the webapps of the Tomcat install. Another option would be to use the manager application if it is installed (this is not always the case), if it's properly configured (i.e. if you have the credentials of a user assigned to the appropriate group) and if it you can access it over an insecure network like Internet (but this is very unlikely and you didn't mention any VPN access). So this leaves you with the webappdirectory.

Now, if Tomcat is installed and running on (as this is the machine where you uploaded the files), I noticed that Apache is listening to port 80 on that machien so I would bet that Tomcat is not directly exposed and that requests have to go through Apache. In that case, I think that deploying a new webapp and making it visible to the Internet will involve the edit of Apache configuration files (mod_jk?, mod_proxy?). You should either give us more details or discuss this with your hosting provider.

Update: As expected, the is using Apache Tomcat + Apache HTTPD + mod_jk. The configuration usually involves two files: the file to configure the workers and the httpd.conf for Apache. Now, without seeing the current configuration, it's not easy to give a definitive answer but, basically, you may have to add a JkMount directive in Apache httpd.conf for your new webapp1. Refer to the mod_jk documentation, it has a simple configuration example. Note that modifying httpd.conf will require access to (obviously) and proper rights and that you'll have to restart Apache after the modifications.

1 I don't think you'll need to define a new worker if you are deploying to an already used Tomcat instance, especially if this sounds like Chinese for you :)

How to run cron job every 2 hours

0 */2 * * *

The answer is from It is interesting.

How to make links in a TextView clickable?

The above solutions didn't work for me, but the following did (and it seems a bit cleaner).
First, in the string resource, define your tag opening chevrons using the HTML entity encoding, i.e.:

&lt;a href="">Google&lt;/a>

and NOT:

<a href="">Google</a>

In general, encode all the chevrons in the string like that. BTW, the link must start with http://

Then (as suggested here) set this option on your TextView:


Finally, in code, do:

((TextView) findViewById(;
((TextView) findViewById(;

That's it, no regexes or other manual hacks required.

how to parse xml to java object?

For performing Unmarshall using JAXB:

1) Convert given XML to XSD(by yourself or by online convertor),

2) Create a JAXB project in eclipse,

3) Create XSD file and paste that converted XSD content in it,

4) Right click on **XSD file--> Generate--> JAXB Classes-->follow the instructions(this will create all nessasary .java files in src, i.e., one package-info, object factory and pojo class),

5) Create another .java file in src to operate unmarshall operation, and run it.

Happy Coding !!

Does Python have an argc argument?

You're better off looking at argparse for argument parsing.

Just makes it easy, no need to do the heavy lifting yourself.

Map and filter an array at the same time

I optimized the answers with the following points:

  1. Rewriting if (cond) { stmt; } as cond && stmt;
  2. Use ES6 Arrow Functions

I'll present two solutions, one using forEach, the other using reduce:

Solution 1: Using forEach

var options = [_x000D_
  { name: 'One', assigned: true }, _x000D_
  { name: 'Two', assigned: false }, _x000D_
  { name: 'Three', assigned: true }, _x000D_
var reduced = []_x000D_
options.forEach(o => {_x000D_
  o.assigned && reduced.push( { name:, newProperty: 'Foo' } );_x000D_
} );_x000D_

Solution 2: Using reduce

var options = [_x000D_
  { name: 'One', assigned: true }, _x000D_
  { name: 'Two', assigned: false }, _x000D_
  { name: 'Three', assigned: true }, _x000D_
var reduced = options.reduce((a, o) => {_x000D_
  o.assigned && a.push( { name:, newProperty: 'Foo' } );_x000D_
  return a;_x000D_
}, [ ] );_x000D_

I leave it up to you to decide which solution to go for.

How are Anonymous inner classes used in Java?

Yes, anonymous inner classes is definitely one of the advantages of Java.

With an anonymous inner class you have access to final and member variables of the surrounding class, and that comes in handy in listeners etc.

But a major advantage is that the inner class code, which is (at least should be) tightly coupled to the surrounding class/method/block, has a specific context (the surrounding class, method, and block).

How to use Visual Studio Code as Default Editor for Git

Just want to add these back slashes to previous answers, I am on Windows 10 CMD, and it doesn't work without back slashes before the spaces.

git config --global core.editor "C:\\Users\\your_user_name\\AppData\\Local\\Programs\\Microsoft\ VS\ Code\\Code.exe"

Javascript to open popup window and disable parent window

This is how I finally did it! You can put a layer (full sized) over your body with high z-index and, of course hidden. You will make it visible when the window is open, make it focused on click over parent window (the layer), and finally will disappear it when the opened window is closed or submitted or whatever.

        position: fixed;
        opacity: 0.7;
        left: 0px;
        top: 0px;
        width: 100%;
        height: 100%;
        z-index: 999999;
        background-color: #BEBEBE;
        display: none;
        cursor: not-allowed;

and layer in the body:

                <div class="layout" id="layout"></div>

function that opens the popup window:

    var new_window;
    function winOpen(){

keeping new window focused:

             $(".layout").click(function(e) {

and in the opened window:

    function submit(){
        var doc = window.opener.document,

   window.onbeforeunload = function(){
        var doc = window.opener.document;

I hope it would help :-)

How do I sort strings alphabetically while accounting for value when a string is numeric?

I guess this will be much more good if it has some numeric in the string. Hope it will help.

PS:I'm not sure about performance or complicated string values but it worked good something like this:

lorem ipsum
lorem ipsum 1
lorem ipsum 2
lorem ipsum 3
lorem ipsum 20
lorem ipsum 21

public class SemiNumericComparer : IComparer<string>
    public int Compare(string s1, string s2)
        int s1r, s2r;
        var s1n = IsNumeric(s1, out s1r);
        var s2n = IsNumeric(s2, out s2r);

        if (s1n && s2n) return s1r - s2r;
        else if (s1n) return -1;
        else if (s2n) return 1;

        var num1 = Regex.Match(s1, @"\d+$");
        var num2 = Regex.Match(s2, @"\d+$");

        var onlyString1 = s1.Remove(num1.Index, num1.Length);
        var onlyString2 = s2.Remove(num2.Index, num2.Length);

        if (onlyString1 == onlyString2)
            if (num1.Success && num2.Success) return Convert.ToInt32(num1.Value) - Convert.ToInt32(num2.Value);
            else if (num1.Success) return 1;
            else if (num2.Success) return -1;

        return string.Compare(s1, s2, true);

    public bool IsNumeric(string value, out int result)
        return int.TryParse(value, out result);

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

Since setEditable(false) is deprecated, use textView.setKeyListener(null); to make editText non-clickable.

Android Service needs to run always (Never pause or stop)

I found a simple and clear way of keeping the Service running always.

This guy has explained it so clearly and have used a good algorithm. His approach is to send a Broadcast when the service is about to get killed and then use it to restart the service.

You should check it out:

jQuery Toggle Text?

Nate-Wilkins's improved function:

    toggleText: function (a, b) {
        var toggle = false, that = this;
        this.on('click', function () {
            that.text((toggle = !toggle) ? b : a);
        return this;


<button class="button-toggle-text">Hello World</button>


$('.button-toggle-text').toggleText("Hello World", "Bye!");

How to zoom div content using jquery?

If you want that image to be zoomed on mouse hover :

$(document).ready( function() {
$('#div img').hover(
    function() {
        $(this).animate({ 'zoom': 1.2 }, 400);
    function() {
        $(this).animate({ 'zoom': 1 }, 400);

?or you may do like this if zoom in and out buttons are used :



function ZoomIn (event) {

    $("#div img").width(
        $("#div img").width() * 1.2

    $("#div img").height(
        $("#div img").height() * 1.2

function  ZoomOut (event) {

    $("#div img").width(
        $("#imgDtls").width() * 0.5

    $("#div img").height(
        $("#div img").height() * 0.5

iOS 8 Snapshotting a view that has not been rendered results in an empty snapshot

I was struggling with this issue for several hours, i have read every relevant topic and found out that the error was caused because under the privacy settings of my device, the camera access to my app was blocked!!! I have never denied access to camera and i don't know how it was blocked but that was the problem!

Is there a way to 'pretty' print MongoDB shell output to a file?

Put your query (e.g. db.someCollection.find().pretty()) to a javascript file, let's say query.js. Then run it in your operating system's shell using command:

mongo yourDb < query.js > outputFile

Query result will be in the file named 'outputFile'.

By default Mongo prints out first 20 documents IIRC. If you want more you can define new value to batch size in Mongo shell, e.g.

DBQuery.shellBatchSize = 100.

VS2010 How to include files in project, to copy them to build output directory automatically during build or publish

Just so my fellow neuronically impaired comrades might chance upon it here, I had assumed that, for web projects, if the linked file was an external .config file that the "output directory" would be the same directory that web.config lives in, i.e. your web project's root. In retrospect, it is entirely unsurprising that it copies the linked file into the root/bin folder.

So, if it's an appSettings include file, your web.config's open tag would be

<appSettings file=".\bin\includedAppSettingsFile.config">


Can I scroll a ScrollView programmatically in Android?

private int totalHeight = 0;

ViewTreeObserver ScrollTr = loutMain.getViewTreeObserver();
ScrollTr.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
    public void onGlobalLayout() {
        } else {
        TotalHeight = loutMain.getMeasuredHeight();


scrollMain.smoothScrollTo(0, totalHeight);

How to insert an item at the beginning of an array in PHP?

Insert an item in the beginning of an associative array with string/custom key


$array = ['keyOne'=>'valueOne', 'keyTwo'=>'valueTwo'];

$array = array_reverse($array);

$array['newKey'] = 'newValue';

$array = array_reverse($array);


  'newKey' => 'newValue',
  'keyOne' => 'valueOne',
  'keyTwo' => 'valueTwo'

How to retrieve an element from a set without removing it?

How about s.copy().pop()? I haven't timed it, but it should work and it's simple. It works best for small sets however, as it copies the whole set.

CSV in Python adding an extra carriage return, on Windows

Python 3:

The official csv documentation recommends opening the file with newline='' on all platforms to disable universal newlines translation:

with open('output.csv', 'w', newline='', encoding='utf-8') as f:
    writer = csv.writer(f)

The CSV writer terminates each line with the lineterminator of the dialect, which is \r\n for the default excel dialect on all platforms.

Python 2:

On Windows, always open your files in binary mode ("rb" or "wb"), before passing them to csv.reader or csv.writer.

Although the file is a text file, CSV is regarded a binary format by the libraries involved, with \r\n separating records. If that separator is written in text mode, the Python runtime replaces the \n with \r\n, hence the \r\r\n observed in the file.

See this previous answer.

How to sort a collection by date in MongoDB?

Additional Square [ ] Bracket is required for sorting parameter to work.

collection.find({}, {"sort" : [['datefield', 'asc']]} ).toArray(function(err,docs) {});

Gridview with two columns and auto resized images

another simple approach with modern built-in stuff like PercentRelativeLayout is now available for new users who hit this problem. thanks to android team for release this item.

< xmlns:android=""

<FrameLayout xmlns:android=""

        android:scaleType="centerCrop" />

        android:textColor="@android:color/white" />


and for better performance you can use some stuff like picasso image loader which help you to fill whole width of every image parents. for example in your adapter you should use this:

int width= context.getResources().getDisplayMetrics().widthPixels;
            .load("some url")

now you dont need CustomImageView Class anymore.

P.S i recommend to use ImageView in place of Type Int in class Item.

hope this help..

Format a Go string without printing?

I've created go project for string formatting from template (it allow to format strings in C# or Python style, just first version for very simple cases), you could find it here

it works in following manner:

func TestStrFormat(t *testing.T) {
    strFormatResult, err := Format("Hello i am {0}, my age is {1} and i am waiting for {2}, because i am {0}!",
                              "Michael Ushakov (Evillord666)", "34", "\"Great Success\"")
    assert.Nil(t, err)
    assert.Equal(t, "Hello i am Michael Ushakov (Evillord666), my age is 34 and i am waiting for \"Great Success\", because i am Michael Ushakov (Evillord666)!", strFormatResult)

    strFormatResult, err = Format("We are wondering if these values would be replaced : {5}, {4}, {0}", "one", "two", "three")
    assert.Nil(t, err)
    assert.Equal(t, "We are wondering if these values would be replaced : {5}, {4}, one", strFormatResult)

    strFormatResult, err = Format("No args ... : {0}, {1}, {2}")
    assert.Nil(t, err)
    assert.Equal(t, "No args ... : {0}, {1}, {2}", strFormatResult)

func TestStrFormatComplex(t *testing.T) {
    strFormatResult, err := FormatComplex("Hello {user} what are you doing here {app} ?", map[string]string{"user":"vpupkin", "app":"mn_console"})
    assert.Nil(t, err)
    assert.Equal(t, "Hello vpupkin what are you doing here mn_console ?", strFormatResult)

Storing query results into a variable and modifying it inside a Stored Procedure

Try this example

    --Stored Procedure variables
    Declare @maxOr int; 
    Declare @maxCa int; 

    --Getting query result in the variable (first variant of syntax)
    SET @maxOr = (SELECT MAX(orId) FROM [order]); 

    --Another variant of seting variable from query
    SELECT @maxCa=MAX(caId) FROM [cart]; 

    --Updating record through the variable
    INSERT INTO [order_cart] (orId,caId)
    VALUES(@maxOr, @maxCa); 

    --return values to the program as dataset
       @maxOr AS maxOr,
       @maxCa AS maxCa

    -- return one int value as "return value"
    RETURN @maxOr

SQL-command to call the stored procedure


Leading zeros for Int in Swift

With Swift 5, you may choose one of the three examples shown below in order to solve your problem.

#1. Using String's init(format:_:) initializer

Foundation provides Swift String a init(format:_:) initializer. init(format:_:) has the following declaration:

init(format: String, _ arguments: CVarArg...)

Returns a String object initialized by using a given format string as a template into which the remaining argument values are substituted.

The following Playground code shows how to create a String formatted from Int with at least two integer digits by using init(format:_:):

import Foundation

let string0 = String(format: "%02d", 0) // returns "00"
let string1 = String(format: "%02d", 1) // returns "01"
let string2 = String(format: "%02d", 10) // returns "10"
let string3 = String(format: "%02d", 100) // returns "100"

#2. Using String's init(format:arguments:) initializer

Foundation provides Swift String a init(format:arguments:) initializer. init(format:arguments:) has the following declaration:

init(format: String, arguments: [CVarArg])

Returns a String object initialized by using a given format string as a template into which the remaining argument values are substituted according to the user’s default locale.

The following Playground code shows how to create a String formatted from Int with at least two integer digits by using init(format:arguments:):

import Foundation

let string0 = String(format: "%02d", arguments: [0]) // returns "00"
let string1 = String(format: "%02d", arguments: [1]) // returns "01"
let string2 = String(format: "%02d", arguments: [10]) // returns "10"
let string3 = String(format: "%02d", arguments: [100]) // returns "100"

#3. Using NumberFormatter

Foundation provides NumberFormatter. Apple states about it:

Instances of NSNumberFormatter format the textual representation of cells that contain NSNumber objects and convert textual representations of numeric values into NSNumber objects. The representation encompasses integers, floats, and doubles; floats and doubles can be formatted to a specified decimal position.

The following Playground code shows how to create a NumberFormatter that returns String? from a Int with at least two integer digits:

import Foundation

let formatter = NumberFormatter()
formatter.minimumIntegerDigits = 2

let optionalString0 = formatter.string(from: 0) // returns Optional("00")
let optionalString1 = formatter.string(from: 1) // returns Optional("01")
let optionalString2 = formatter.string(from: 10) // returns Optional("10")
let optionalString3 = formatter.string(from: 100) // returns Optional("100")

Android Fatal signal 11 (SIGSEGV) at 0x636f7d89 (code=1). How can it be tracked down?

I've encountered this error when I tried to access the 'canvas' outside of onDraw()

    private Canvas canvas;

    protected void onDraw(Canvas canvas) {
        this.canvas = canvas;
        ....... }

    private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
        public boolean onScale(ScaleGestureDetector detector) { 
  ; // here

A very bad practice :/

Timeout function if it takes too long to finish

I rewrote David's answer using the with statement, it allows you do do this:

with timeout(seconds=3):

Which will raise a TimeoutError.

The code is still using signal and thus UNIX only:

import signal

class timeout:
    def __init__(self, seconds=1, error_message='Timeout'):
        self.seconds = seconds
        self.error_message = error_message
    def handle_timeout(self, signum, frame):
        raise TimeoutError(self.error_message)
    def __enter__(self):
        signal.signal(signal.SIGALRM, self.handle_timeout)
    def __exit__(self, type, value, traceback):

How can I read comma separated values from a text file in Java?

Use OpenCSV for reliability. Split should never be used for these kind of things. Here's a snippet from a program of my own, it's pretty straightforward. I check if a delimiter character was specified and use this one if it is, if not I use the default in OpenCSV (a comma). Then i read the header and fields

CSVReader reader = null;
try {
    if (delimiter > 0) {
        reader = new CSVReader(new FileReader(this.csvFile), this.delimiter);
    else {
        reader = new CSVReader(new FileReader(this.csvFile));

    // these should be the header fields
    header = reader.readNext();
    while ((fields = reader.readNext()) != null) {
        // more code
catch (IOException e) {

How to load a controller from another controller in codeigniter?

Create a helper using the code I created belows and name it controller_helper.php.

Autoload your helper in the autoload.php file under config.

From your method call controller('name') to load the controller.

Note that name is the filename of the controller.

This method will append '_controller' to your controller 'name'. To call a method in the controller just run $this->name_controller->method(); after you load the controller as described above.


    function controller($name)
        $filename = realpath(__dir__ . '/../controllers/'.$name.'.php');

            require_once $filename;

            $class = ucfirst($name);

                $ci =& get_instance();

                    $ci->{$name.'_controller'} = new $class();

Disable clipboard prompt in Excel VBA on workbook close

If you don't want to save any changes and don't want that Save prompt while saving an Excel file using Macro then this piece of code may helpful for you

Sub Auto_Close()

     ThisWorkbook.Saved = True

End Sub

Because the Saved property is set to True, Excel responds as though the workbook has already been saved and no changes have occurred since that last save, so no Save prompt.

How to check if PHP array is associative or sequential?

This function can handle:

  • array with holes in index (e.g. 1,2,4,5,8,10)
  • array with "0x" keys: e.g. key '08' is associative while key '8' is sequential.

the idea is simple: if one of the keys is NOT an integer, it is associative array, otherwise it's sequential.

function is_asso($a){
    foreach(array_keys($a) as $key) {if (!is_int($key)) return TRUE;}
    return FALSE;

How do you initialise a dynamic array in C++?

Two ways:

char *c = new char[length];
std::fill(c, c + length, INITIAL_VALUE);
// just this once, since it's char, you could use memset


std::vector<char> c(length, INITIAL_VALUE);

In my second way, the default second parameter is 0 already, so in your case it's unnecessary:

std::vector<char> c(length);

[Edit: go vote for Fred's answer, char* c = new char[length]();]

Why does git say "Pull is not possible because you have unmerged files"?

You have some files locally that need to be merged before you can pull. You could checkout the files and then pull to overwrite your local files.

git checkout app/config/app.php app/config/database.php app/routes.php
git pull origin master

PHP Unset Session Variable

Unset is a function. Therefore you have to submit which variable has to be destroyed.


In your case

unset ($_SESSION["products"]);

If you need to reset whole session variable just call

session_destroy ();

Eclipse - debugger doesn't stop at breakpoint

In my case I had multiple projects in same workspace. The java file I was trying to debug was present in more than one projects with same package.

I didn't need the other project, so simply closed unrelated projects (or remove the file from unrelated project).

Cannot find Microsoft.Office.Interop Visual Studio

With Visual Studio 2015 I have activated it with the following steps.

  1. Programs and Features --> Select Visual Studio > Change
  2. Choose Modify
  3. Windows and Webdevelopment --> Tick "Microsoft Office Developer Tools"
  4. Start Update

It should work now.

Div Height in Percentage

It doesn't take the 50% of the whole page is because the "whole page" is only how tall your contents are. Change the enclosing html and body to 100% height and it will work.

html, body{
    height: 100%;
    height: 50%;

enter image description here

^ Your document is only 20px high. 50% of 20px is 10px, and it is not what you expected.

enter image description here

^ Now if you change the height of the document to the height of the whole page (150px), 50% of 150px is 75px, then it will work.

Reordering Chart Data Series

To change the stacking order for series in charts under Excel for Mac 2011:

  1. select the chart,
  2. select the series (easiest under Ribbon>Chart Layout>Current Selection),
  3. click Chart Layout>Format Selection or Menu>Format>Data Series …,
  4. on popup menu Format Data Series click Order, then click individual series and click Move Up or Move Down buttons to adjust the stacking order on the Axis for the subject series. This changes the order for the plot and for the legend, but may not change the order number in the Series formula.

I had a three series plot on the secondary axis, and the series I wanted on top was stuck on the bottom in defiance of the Move Up and Move Down buttons. It happened to be formatted as markers only. I inserted a line, and presto(!), I could change its order in the plot. Later I could remove the line and sometimes it could still be ordered, but sometimes not.

Convert dictionary to bytes and back again python?

If you need to convert the dictionary to binary, you need to convert it to a string (JSON) as described in the previous answer, then you can convert it to binary.

For example:

my_dict = {'key' : [1,2,3]}

import json
def dict_to_binary(the_dict):
    str = json.dumps(the_dict)
    binary = ' '.join(format(ord(letter), 'b') for letter in str)
    return binary

def binary_to_dict(the_binary):
    jsn = ''.join(chr(int(x, 2)) for x in the_binary.split())
    d = json.loads(jsn)  
    return d

bin = dict_to_binary(my_dict)
print bin

dct = binary_to_dict(bin)
print dct

will give the output

1111011 100010 1101011 100010 111010 100000 1011011 110001 101100 100000 110010 101100 100000 110011 1011101 1111101

{u'key': [1, 2, 3]}

Remove the first character of a string

deleting a char:

def del_char(string, indexes):

    'deletes all the indexes from the string and returns the new one'

    return ''.join((char for idx, char in enumerate(string) if idx not in indexes))

it deletes all the chars that are in indexes; you can use it in your case with del_char(your_string, [0])

Check whether $_POST-value is empty

If the form was successfully submitted, $_POST['userName'] should always be set, though it may contain an empty string, which is different from not being set at all. Instead check if it is empty()

if (isset($_POST['submit'])) {
    if (empty($_POST['userName'])) {
        $username = 'Anonymous';
    } else { 
        $username = $_POST['userName'];

Switch android x86 screen resolution

Verified the following on Virtualbox-5.0.24, Android_x86-4.4-r5. You get a screen similar to an 8" table. You can play around with the xxx in DPI=xxx, to change the resolution. xxx=100 makes it really small to match a real table exactly, but it may be too small when working with android in Virtualbox.

VBoxManage setextradata <VmName> "CustomVideoMode1" "440x680x16"

With the following appended to android kernel cmd:

UVESA_MODE=440x680 DPI=120

How to add icon to mat-icon-button

My preference is to utilize the inline attribute. This will cause the icon to correctly scale with the size of the button.

    <button mat-button>
      <mat-icon inline=true>local_movies</mat-icon>

    <!-- Link button -->
    <a mat-flat-button color="accent" routerLink="/create"><mat-icon inline=true>add</mat-icon> Create</a>

I add this to my styles.css to:

  • solve the vertical alignment problem of the icon inside the button
  • material icon fonts are always a little too small compared to button text
button.mat-button .mat-icon,
a.mat-button .mat-icon,
a.mat-raised-button .mat-icon,
a.mat-flat-button .mat-icon,
a.mat-stroked-button .mat-icon {
  vertical-align: top;
  font-size: 1.25em;

Tree implementation in Java (root, parents and children)

import java.util.ArrayList;
import java.util.List;

public class Node<T> {
    private List<Node<T>> children = new ArrayList<Node<T>>();
    private Node<T> parent = null;
    private T data = null;

    public Node(T data) { = data;

    public Node(T data, Node<T> parent) { = data;
        this.parent = parent;

    public List<Node<T>> getChildren() {
        return children;

    public void setParent(Node<T> parent) {
        this.parent = parent;

    public void addChild(T data) {
        Node<T> child = new Node<T>(data);

    public void addChild(Node<T> child) {

    public T getData() {

    public void setData(T data) { = data;

    public boolean isRoot() {
        return (this.parent == null);

    public boolean isLeaf() {
        return this.children.size == 0;

    public void removeParent() {
        this.parent = null;


import java.util.List;

Node<String> parentNode = new Node<String>("Parent"); 
Node<String> childNode1 = new Node<String>("Child 1", parentNode);
Node<String> childNode2 = new Node<String>("Child 2");     


Node<String> grandchildNode = new Node<String>("Grandchild of parentNode. Child of childNode1", childNode1); 
List<Node<String>> childrenNodes = parentNode.getChildren();

Is it possible to use jQuery .on and hover?

You can provide one or multiple event types separated by a space.

So hover equals mouseenter mouseleave.

This is my sugession:

$("#foo").on("mouseenter mouseleave", function() {
    // do some stuff

What is the minimum I have to do to create an RPM file?

Similarly, I needed to create an rpm with just a few files. Since these files were source controlled, and because it seemed silly, I didn't want to go through taring them up just to have rpm untar them. I came up with the following:

  1. Set up your environment:

    mkdir -p ~/rpm/{BUILD,RPMS}

    echo '%_topdir %(echo "$HOME")/rpm' > ~/.rpmmacros

  2. Create your spec file, foobar.spec, with the following contents:

    Summary: Foo to the Bar
    Name: foobar
    Version: 0.1
    Release: 1
    Group: Foo/Bar
    License: FooBarPL
    Source: %{expand:%%(pwd)}
    BuildRoot: %{_topdir}/BUILD/%{name}-%{version}-%{release}
    rm -rf $RPM_BUILD_ROOT
    mkdir -p $RPM_BUILD_ROOT/usr/bin
    mkdir -p $RPM_BUILD_ROOT/etc
    cp %{SOURCEURL0}/foobar ./usr/bin/
    cp %{SOURCEURL0}/foobar.conf ./etc/
    rm -r -f "$RPM_BUILD_ROOT"
    %config(noreplace) %{_sysconfdir}/foobar.conf
  3. Build your rpm: rpmbuild -bb foobar.spec

There's a little hackery there specifying the 'source' as your current directory, but it seemed far more elegant then the alternative, which was to, in my case, write a separate script to create a tarball, etc, etc.

Note: In my particular situation, my files were arranged in folders according to where they needed to go, like this:


and so the prep section became:

mkdir -p $RPM_BUILD_ROOT
tar -cC %{SOURCEURL0} --exclude 'foobar.spec' -f - ./ | tar xf -

Which is a little cleaner.

Also, I happen to be on a RHEL5.6 with rpm versions, so your mileage may vary.

Reading NFC Tags with iPhone 6 / iOS 8

At the moment, there isn't any open access to the NFC controller. There are currently no NFC APIs in the iOS 8 GM SDK - which would indicate that the NFC capability will be restricted to Apple Pay at launch. This is our understanding.

Clearly, the NXP chip inside the iPhone 6 is likely to be able to do more so this doesn't mean that additional features (pairing, tag scanning/encoding) will not be added for release or in the near future.

Where is the Global.asax.cs file?

That's because you created a Web Site instead of a Web Application. The cs/vb files can only be seen in a Web Application, but in a website you can't have a separate cs/vb file.

Edit: In the website you can add a cs file behavior like..

<%@ Application CodeFile="Global.asax.cs" Inherits="ApplicationName.MyApplication" Language="C#" %>


namespace ApplicationName
    public partial class MyApplication : System.Web.HttpApplication
        protected void Application_Start()

How can I create a progress bar in Excel VBA?

In the past, with VBA projects, I've used a label control with the background colored and adjust the size based on the progress. Some examples with similar approaches can be found in the following links:


Here is one that uses Excel's Autoshapes:

Spring JDBC Template for calling Stored Procedures

There are a number of ways to call stored procedures in Spring.

If you use CallableStatementCreator to declare parameters, you will be using Java's standard interface of CallableStatement, i.e register out parameters and set them separately. Using SqlParameter abstraction will make your code cleaner.

I recommend you looking at SimpleJdbcCall. It may be used like this:

SimpleJdbcCall jdbcCall = new SimpleJdbcCall(jdbcTemplate)
jdbcCall.addDeclaredParameter(new SqlParameter(paramName, OracleTypes.NUMBER));

For simple procedures you may use jdbcTemplate's update method:

jdbcTemplate.update("call SOME_PROC (?, ?)", param1, param2);

How to remove text from a string?

You can use "data-123".replace('data-','');, as mentioned, but as replace() only replaces the FIRST instance of the matching text, if your string was something like "data-123data-" then


will only replace the first matching text. And your output will be "123data-"


So if you want all matches of text to be replaced in string you have to use a regular expression with the g flag like that:


And your output will be "123"


Render partial from different folder (not shared)

I've created a workaround that seems to be working pretty well. I found the need to switch to the context of a different controller for action name lookup, view lookup, etc. To implement this, I created a new extension method for HtmlHelper:

public static IDisposable ControllerContextRegion(
    this HtmlHelper html, 
    string controllerName)
    return new ControllerContextRegion(html.ViewContext.RouteData, controllerName);

ControllerContextRegion is defined as:

internal class ControllerContextRegion : IDisposable
    private readonly RouteData routeData;
    private readonly string previousControllerName;

    public ControllerContextRegion(RouteData routeData, string controllerName)
        this.routeData = routeData;
        this.previousControllerName = routeData.GetRequiredString("controller");

    public void Dispose()

    private void SetControllerName(string controllerName)
        this.routeData.Values["controller"] = controllerName;

The way this is used within a view is as follows:

@using (Html.ControllerContextRegion("Foo")) {
    // Html.Action, Html.Partial, etc. now looks things up as though
    // FooController was our controller.

There may be unwanted side effects for this if your code requires the controller route component to not change, but in our code so far, there doesn't seem to be any negatives to this approach.

Input jQuery get old value before onchange and get value after on change

Just put the initial value into a data attribute when you create the textbox, eg


<input id="my-textbox" type="text" data-initial-value="6" value="6" /> 


$("#my-textbox").change(function () {
 var oldValue = $(this).attr("data-initial-value");
 var newValue = $(this).val();

php convert datetime to UTC

As strtotime requires specific input format, DateTime::createFromFormat could be used (php 5.3+ is required)

// set timezone to user timezone

// create date object using any given format
$date = DateTime::createFromFormat($str_user_dateformat, $str_user_datetime);

// convert given datetime to safe format for strtotime
$str_user_datetime = $date->format('Y-m-d H:i:s');

// convert to UTC
$str_UTC_datetime = gmdate($str_server_dateformat, strtotime($str_user_datetime));

// return timezone to server default

How to install Google Play Services in a Genymotion VM (with no drag and drop support)?

Drag and Drop did not work on my system...

I found a blogpost which describes how you install it with adb:

adb push /sdcard/Download/

adb push /sdcard/Download/

adb shell /sdcard/Download/

adb reboot

adb shell /sdcard/Download/

adb reboot

How do I convert a IPython Notebook into a Python file via commandline?

I understand this is an old thread. I have faced the same issue and wanted to convert the .pynb file to .py file via command line.

My search took me to ipynb-py-convert

By following below steps I was able to get .py file

  1. Install "pip install ipynb-py-convert"
  2. Go to the directory where the ipynb file is saved via command prompt
  3. Enter the command

> ipynb-py-convert YourFileName.ipynb

Eg:. ipynb-py-convert getting-started-with-kaggle-titanic-problem.ipynb

Above command will create a python script with the name "" and as per our example it will create file

ReferenceError: document is not defined (in plain JavaScript)

try: window.document......

var body = window.document.getElementsByTagName("body")[0];

Find out if string ends with another string in C++

Use std::equal algorithm from <algorithms> with reverse iteration:

std::string LogExt = ".log";
if (std::equal(LogExt.rbegin(), LogExt.rend(), filename.rbegin())) {

Export to xls using angularjs

If you load your data into ng-grid, you can use the CSV export plugin. The plugin creates a button with the grid data as csv inside an href tag.

Updating links as the library got renamed:

Github link:

Library page:

Documentation on csv export :

Kubernetes service external ip pending

In case someone is using MicroK8s: You need a network load balancer.

MicroK8s comes with metallb, you can enable it like this:

microk8s enable metallb

<pending> should turn into an actual IP address then.

Bootstrap NavBar with left, center or right aligned items

The simplest solution:

Just divide the navbar into columns: for instance, if you have 24 columns over all, 12 are going to be empty and 12 are going to contrain the navbar:

<nav class="navbar navbar-default">
    <div class="row">
       <div class="col-sm-4"></div>
       <div class="col-sm-4"></div>
       <div class="col-sm-4"></div>

       <div class="col-sm-12">
           <ul class="nav navbar-nav" align="center">
              <li><a href="#">Home</a></li>
              <li><a href="#">First Link</a></li>
              <li><a href="#">Second Link</a></li>
              <li><a href="#">Third Link</a></li>
              <li><a href="#">Fourth Link</a></li>

Python copy files to a new directory and rename if file name already exists

Sometimes it is just easier to start over... I apologize if there is any typo, I haven't had the time to test it thoroughly.

movdir = r"C:\Scans"
basedir = r"C:\Links"
# Walk through all files in the directory that contains the files to copy
for root, dirs, files in os.walk(movdir):
    for filename in files:
        # I use absolute path, case you want to move several dirs.
        old_name = os.path.join( os.path.abspath(root), filename )

        # Separate base from extension
        base, extension = os.path.splitext(filename)

        # Initial new name
        new_name = os.path.join(basedir, base, filename)

        # If folder basedir/base does not exist... You don't want to create it?
        if not os.path.exists(os.path.join(basedir, base)):
            print os.path.join(basedir,base), "not found" 
            continue    # Next filename
        elif not os.path.exists(new_name):  # folder exists, file does not
            shutil.copy(old_name, new_name)
        else:  # folder exists, file exists as well
            ii = 1
            while True:
                new_name = os.path.join(basedir,base, base + "_" + str(ii) + extension)
                if not os.path.exists(new_name):
                   shutil.copy(old_name, new_name)
                   print "Copied", old_name, "as", new_name
                ii += 1

Proper way to exit command line program?

Using control-z suspends the process (see the output from stty -a which lists the key stroke under susp). That leaves it running, but in suspended animation (so it is not using any CPU resources). It can be resumed later.

If you want to stop a program permanently, then any of interrupt (often control-c) or quit (often control-\) will stop the process, the latter producing a core dump (unless you've disabled them). You might also use a HUP or TERM signal (or, if really necessary, the KILL signal, but try the other signals first) sent to the process from another terminal; or you could use control-z to suspend the process and then send the death threat from the current terminal, and then bring the (about to die) process back into the foreground (fg).

Note that all key combinations are subject to change via the stty command or equivalents; the defaults may vary from system to system.

What are the benefits to marking a field as `readonly` in C#?

There can be a performance benefit in WPF, as it removes the need for expensive DependencyProperties. This can be especially useful with collections

How to decide when to use Node.js?

The most important reasons to start your next project using Node ...

  • All the coolest dudes are into it ... so it must be fun.
  • You can hangout at the cooler and have lots of Node adventures to brag about.
  • You're a penny pincher when it comes to cloud hosting costs.
  • Been there done that with Rails
  • You hate IIS deployments
  • Your old IT job is getting rather dull and you wish you were in a shiny new Start Up.

What to expect ...

  • You'll feel safe and secure with Express without all the server bloatware you never needed.
  • Runs like a rocket and scales well.
  • You dream it. You installed it. The node package repo is the largest ecosystem of open source libraries in the world.
  • Your brain will get time warped in the land of nested callbacks ...
  • ... until you learn to keep your Promises.
  • Sequelize and Passport are your new API friends.
  • Debugging mostly async code will get umm ... interesting .
  • Time for all Noders to master Typescript.

Who uses it?

  • PayPal, Netflix, Walmart, LinkedIn, Groupon, Uber, GoDaddy, Dow Jones
  • Here's why they switched to Node.

Creating a file only if it doesn't exist in Node.js

Todo this in a single system call you can use the fs-extra npm module. After this the file will have been created as well as the directory it is to be placed in.

const fs = require('fs-extra');
const file = '/tmp/this/path/does/not/exist/file.txt'
fs.ensureFile(file, err => {
    console.log(err) // => null

Another way is to use ensureFileSync which will do the same thing but synchronous.

const fs = require('fs-extra');
const file = '/tmp/this/path/does/not/exist/file.txt'

Call parent method from child class c#

One way to do this would be to pass the instance of ParentClass to the ChildClass on construction

public ChildClass
    private ParentClass parent;

    public ChildClass(ParentClass parent)
        this.parent = parent;

    public void LoadData(DateTable dt)
       // do something
       parent.CurrentRow++; // or whatever.
       parent.UpdateProgressBar(); // Call the method

Make sure to pass the reference to this when constructing ChildClass inside parent:


     ChildClass childClass = new ChildClass(this); // here



Caveat: This is probably not the best way to organise your classes, but it directly answers your question.

EDIT: In the comments you mention that more than 1 parent class wants to use ChildClass. This is possible with the introduction of an interface, eg:

public interface IParentClass
    void UpdateProgressBar();
    int CurrentRow{get; set;}

Now, make sure to implement that interface on both (all?) Parent Classes and change child class to this:

public ChildClass
    private IParentClass parent;

    public ChildClass(IParentClass parent)
        this.parent = parent;

    public void LoadData(DateTable dt)
       // do something
       parent.CurrentRow++; // or whatever.
       parent.UpdateProgressBar(); // Call the method

Now anything that implements IParentClass can construct an instance of ChildClass and pass this to its constructor.

Ajax using https on an http page


most JS libraries make it just as easy as other AJAX calls, but internally use an iframe to do the query.

if you're not using JSON for your payload, then you'll have to roll your own mechanism around the iframe.

personally, i'd just redirect form the http:// page to the https:// one

Add URL link in CSS Background Image?

You can not add links from CSS, you will have to do so from the HTML code explicitly. For example, something like this:

<a href="whatever.html"><li id="header"></li></a>

how to loop through json array in jquery?

var data=[{'com':'something'},{'com':'some other thing'}];
$.each(data, function() {
  $.each(this, function(key, val){
    alert(val);//here data 
      alert (key); //here key


Accessing a Shared File (UNC) From a Remote, Non-Trusted Domain With Credentials

Rather than WNetUseConnection, I would recommend NetUseAdd. WNetUseConnection is a legacy function that's been superceded by WNetUseConnection2 and WNetUseConnection3, but all of those functions create a network device that's visible in Windows Explorer. NetUseAdd is the equivalent of calling net use in a DOS prompt to authenticate on a remote computer.

If you call NetUseAdd then subsequent attempts to access the directory should succeed.

findAll() in yii

Use the below code. This should work.

$comments = EmailArchive::find()->where(['email_id' => $id])->all();

What is difference between CrudRepository and JpaRepository interfaces in Spring Data JPA?

Below are the differences between CrudRepository and JpaRepository as:


  1. CrudRepository is a base interface and extends the Repository interface.
  2. CrudRepository mainly provides CRUD (Create, Read, Update, Delete) operations.
  3. Return type of saveAll() method is Iterable.
  4. Use Case - To perform CRUD operations, define repository extending CrudRepository.


  1. JpaRepository extends PagingAndSortingRepository that extends CrudRepository.
  2. JpaRepository provides CRUD and pagination operations, along with additional methods like flush(), saveAndFlush(), and deleteInBatch(), etc.
  3. Return type of saveAll() method is a List.
  4. Use Case - To perform CRUD as well as batch operations, define repository extends JpaRepository.

Find duplicate entries in a column

Try this query.. It uses the Analytic function SUM:

 FROM table1 a 
 WHERE s_ind ='Y'   
WHERE cnt > 2

Am not sure why you are identifying a record as a duplicate if the ctn_no repeats more than 2 times. FOr me it repeats more than once it is a duplicate. In this case change the las part of the query to WHERE cnt > 1

Error CS2001: Source file '.cs' could not be found

They are likely still referenced by the project file. Make sure they are deleted using the Solution Explorer in Visual Studio - it should show them as being missing (with an exclamation mark).

Get protocol + host name from URL

This is a bit obtuse, but uses urlparse in both directions:

import urlparse
def uri2schemehostname(uri):
    urlparse.urlunparse(urlparse.urlparse(uri)[:2] + ("",) * 4)

that odd ("",) * 4 bit is because urlparse expects a sequence of exactly len(urlparse.ParseResult._fields) = 6

CSS Animation and Display None

How do I have a div not take up space until it is timed to come in (using CSS for the timing.)

Here is my solution to the same problem.

Moreover I have an onclick on the last frame loading another slideshow, and it must not be clickable until the last frame is visible.

Basically my solution is to keep the div 1 pixel high using a scale(0.001), zooming it when I need it. If you don't like the zoom effect you can restore the opacity to 1 after zooming the slide.

#Slide_TheEnd {

    -webkit-animation-delay: 240s;
    animation-delay: 240s;

    -moz-animation-timing-function: linear;
    -webkit-animation-timing-function: linear;
    animation-timing-function: linear;

    -moz-animation-duration: 20s;
    -webkit-animation-duration: 20s;
    animation-duration: 20s;

    -moz-animation-name: Slide_TheEnd;
    -webkit-animation-name: Slide_TheEnd;
    animation-name: Slide_TheEnd;

    -moz-animation-iteration-count: 1;
    -webkit-animation-iteration-count: 1;
    animation-iteration-count: 1;

    -moz-animation-direction: normal;
    -webkit-animation-direction: normal;
    animation-direction: normal;

    -moz-animation-fill-mode: forwards;
    -webkit-animation-fill-mode: forwards;
    animation-fill-mode: forwards;

    transform: scale(0.001);
    background: #cf0;
    text-align: center;
    font-size: 10vh;
    opacity: 0;

@-moz-keyframes Slide_TheEnd {
    0% { opacity: 0;  transform: scale(0.001); }
    10% { opacity: 1; transform: scale(1); }
    95% { opacity: 1; transform: scale(1); }
    100% { opacity: 0;  transform: scale(0.001); }

Other keyframes are removed for the sake of bytes. Please disregard the odd coding, it is made by a php script picking values from an array and str_replacing a template: I'm too lazy to retype everything for every proprietary prefix on a 100+ divs slideshow.

Convert a timedelta to days, hours and minutes

Here is a little function I put together to do this right down to microseconds:

def tdToDict(td:datetime.timedelta) -> dict:
    def __t(t, n):
        if t < n: return (t, 0)
        v = t//n
        return (t -  (v * n), v)
    (s, h) = __t(td.seconds, 3600)
    (s, m) = __t(s, 60)    
    (micS, milS) = __t(td.microseconds, 1000)

    return {
         'days': td.days
        ,'hours': h
        ,'minutes': m
        ,'seconds': s
        ,'milliseconds': milS
        ,'microseconds': micS

Here is a version that returns a tuple:

# usage: (_d, _h, _m, _s, _mils, _mics) = tdTuple(td)
def tdTuple(td:datetime.timedelta) -> tuple:
    def _t(t, n):
        if t < n: return (t, 0)
        v = t//n
        return (t -  (v * n), v)
    (s, h) = _t(td.seconds, 3600)
    (s, m) = _t(s, 60)    
    (mics, mils) = _t(td.microseconds, 1000)
    return (td.days, h, m, s, mics, mils)

Excel - programm cells to change colour based on another cell

  1. Select cell B3 and click the Conditional Formatting button in the ribbon and choose "New Rule".
  2. Select "Use a formula to determine which cells to format"
  3. Enter the formula: =IF(B2="X",IF(B3="Y", TRUE, FALSE),FALSE), and choose to fill green when this is true
  4. Create another rule and enter the formula =IF(B2="X",IF(B3="W", TRUE, FALSE),FALSE) and choose to fill red when this is true.

More details - conditional formatting with a formula applies the format when the formula evaluates to TRUE. You can use a compound IF formula to return true or false based on the values of any cells.

How can I configure my makefile for debug and release builds?

If by configure release/build, you mean you only need one config per makefile, then it is simply a matter and decoupling CC and CFLAGS:

CC=g++ -g3 -gdwarf2 $(CFLAGS)

Depending on whether you can use gnu makefile, you can use conditional to make this a bit fancier, and control it from the command line:

DEBUG ?= 1
ifeq ($(DEBUG), 1)

.o: .c
    $(CC) -c $< -o $@ $(CFLAGS)

and then use:

make DEBUG=0
make DEBUG=1

If you need to control both configurations at the same time, I think it is better to have build directories, and one build directory / config.

How do I move to end of line in Vim?

  • $ moves to the last character on the line.
  • g _ goes to the last non-whitespace character.

  • g $ goes to the end of the screen line (when a buffer line is wrapped across multiple screen lines)

How to include files outside of Docker's build context?

I spent a good time trying to figure out a good pattern and how to better explain what's going on with this feature support. I realized that the best way to explain it was as follows...

  • Dockerfile: Will only see files under its own relative path
  • Context: a place in "space" where the files you want to share and your Dockerfile will be copied to

So, with that said, here's an example of the Dockerfile that needs to reuse a file called


It will always load from its relative path, having the current directory of itself as the local reference to the paths you specify.

COPY /runtime/


Considering this idea, we can think of having multiple copies for the Dockerfiles building specific things, but they all need access to the


Considering this structure and the files above, here's a docker-compose.yml


  • In this example, your shared context directory is the runtime directory.
    • Same mental model here, think that all the files under this directory are moved over to the so-called context.
    • Similarly, just specify the Dockerfile that you want to copy to that same directory. You can specify that using dockerfile.
  • The directory where your main content is located is the actual context to be set.

The docker-compose.yml is as follows

version: "3.3"
      context: ./all-service
      dockerfile: ./service-A/Dockerfile

      context: ./all-service
      dockerfile: ./service-B/Dockerfile

      context: ./all-service
      dockerfile: ./service-C/Dockerfile
  • all-service is set as the context, the shared file is copied there as well the Dockerfile specified by each dockerfile.
  • Each gets to be built their own way, sharing the start file!

How to run bootRun with spring profile via gradle task

my way:



in build.gradle add VM options

bootRun {
   jvmArgs = ["-Dspring.output.ansi.enabled=ALWAYS",""+profile]

this will override application option

How to delete a folder and all contents using a bat file in windows?

  1. del /s /q c:\where ever the file is\*
  2. rmdir /s /q c:\where ever the file is\
  3. mkdir c:\where ever the file is\

How to get a jqGrid selected row cells value

Just Checkout This :

Solution 1 :

In Subgrid Function You have to write following :

var selectid = $(this).jqGrid('getCell', row_id, 'id');

Where row_id is the variable which you define in subgrid as parameter. And id is the column name which you want to get value of the cell.

Solution 2 :

If You Get Jqgrid Row Id In alert Then set your primary key id as key:true In ColModels. So You will get value of your database id in alert. Like this :

{name:"id",index:"id",hidden:true, width:15,key:true, jsonmap:"id"},

Grid of responsive squares

You can make responsive grid of squares with verticaly and horizontaly centered content only with CSS. I will explain how in a step by step process but first here are 2 demos of what you can achieve :

Responsive 3x3 square grid Responsive square images in a 3x3 grid

Now let's see how to make these fancy responsive squares!

1. Making the responsive squares :

The trick for keeping elements square (or whatever other aspect ratio) is to use percent padding-bottom.
Side note: you can use top padding too or top/bottom margin but the background of the element won't display.

As top padding is calculated according to the width of the parent element (See MDN for reference), the height of the element will change according to its width. You can now Keep its aspect ratio according to its width.
At this point you can code :




div {
    width: 30%;
    padding-bottom: 30%; /* = width for a square aspect ratio */

Here is a simple layout example of 3*3 squares grid using the code above.

With this technique, you can make any other aspect ratio, here is a table giving the values of bottom padding according to the aspect ratio and a 30% width.

 Aspect ratio  |  padding-bottom  |  for 30% width
    1:1        |  = width         |    30%
    1:2        |  width x 2       |    60%
    2:1        |  width x 0.5     |    15%
    4:3        |  width x 0.75    |    22.5%
    16:9       |  width x 0.5625  |    16.875%

2. Adding content inside the squares

As you can't add content directly inside the squares (it would expand their height and squares wouldn't be squares anymore) you need to create child elements (for this example I am using divs) inside them with position: absolute; and put the content inside them. This will take the content out of the flow and keep the size of the square.

Don't forget to add position:relative; on the parent divs so the absolute children are positioned/sized relatively to their parent.

Let's add some content to our 3x3 grid of squares :


<div class="square">
    <div class="content">
        .. CONTENT HERE ..
... and so on 9 times for 9 squares ...


.square {
    position: relative;
    width: 30%;
    padding-bottom: 30%; /* = width for a 1:1 aspect ratio */

.content {
    height:80%; /* = 100% - 2*10% padding */
    width:90%; /* = 100% - 2*5% padding */
    padding: 10% 5%;

RESULT <-- with some formatting to make it pretty!

3.Centering the content

Horizontally :

This is pretty easy, you just need to add text-align:center to .content.

Vertical alignment

This becomes serious! The trick is to use

/* and */

but we can't use display:table; on .square or .content divs because it conflicts with position:absolute; so we need to create two children inside .content divs. Our code will be updated as follow :


<div class="square">
    <div class="content">
        <div class="table">
            <div class="table-cell">
                ... CONTENT HERE ...
... and so on 9 times for 9 squares ...


.square {
    position: relative;
    width: 30%;
    padding-bottom : 30%; /* = width for a 1:1 aspect ratio */

.content {
    height:80%; /* = 100% - 2*10% padding */
    width:90%; /* = 100% - 2*5% padding */
    padding: 10% 5%;

We have now finished and we can take a look at the result here :


editable fiddle here

How to get last items of a list in Python?

a negative index will count from the end of the list, so:


How do I use PHP namespaces with autoload?

I'll throw in my two cents for relative beginners or whatnot wanting a simple spl_autoload_register() setup without all the theory: Just create one php file for each class, name that php file the same as your class name, and keep your class files in the same directory as your php file in question, then this will work:

spl_autoload_register(function ($class_name) {
    require_once dirname(__FILE__) . DIRECTORY_SEPARATOR . $class_name . '.php';

Googling the pieces inside this function should answer how it works. PS: I use Linux, and this works on Linux. Windows folks should test it out first.

Using ListView : How to add a header view?

You simply can't use View as a Header of ListView.

Because the view which is being passed in has to be inflated.

Look at my answer at Android ListView addHeaderView() nullPointerException for predefined Views for more info.


Look at this tutorial Android ListView and ListActivity - Tutorial .

EDIT 2: This link is broken Android ListActivity with a header or footer

Installing PIL with pip

On Mac OS X, use this command:

sudo pip install

What is the alternative for ~ (user's home directory) on Windows command prompt?

Use %systemdrive%%homepath%. %systemdrive% gives drive character ( Mostly C: ) and %homepath% gives user home directory ( \Users\<USERNAME> ).

How to fix 'Unchecked runtime.lastError: The message port closed before a response was received' chrome issue?

This error is generally caused by one of your Chrome extensions.

I recommend installing this One-Click Extension Disabler, I use it with the keyboard shortcut COMMAND (?) + SHIFT (?) + D — to quickly disable/enable all my extensions.

Once the extensions are disabled this error message should go away.

Peace! ??

What is makeinfo, and how do I get it?

Another option is to use apt-file (i.e. apt-file search makeinfo). It may or may not be installed in your distro by default, but it is a great tool for determining what package a file belongs to.

How do you list the primary key of a SQL Server table?

This should list all the constraints ( primary Key and Foreign Keys ) and at the end of query put table name

        PARENT_COL_NAME_DATA_TYPE=  oParentColDtl.DATA_TYPE,        

FROM sys.key_constraints as PKnUKEY
    INNER JOIN sys.tables as PKnUTable
            ON PKnUTable.object_id = PKnUKEY.parent_object_id
    INNER JOIN sys.index_columns as PKnUColIdx
            ON PKnUColIdx.object_id = PKnUTable.object_id
            AND PKnUColIdx.index_id = PKnUKEY.unique_index_id
    INNER JOIN sys.columns as PKnUKEYCol
            ON PKnUKEYCol.object_id = PKnUTable.object_id
            AND PKnUKEYCol.column_id = PKnUColIdx.column_id
        PARENT_COL_NAME_DATA_TYPE= oParentColDtl.DATA_TYPE,     
FROM sys.foreign_key_columns FKC
    INNER JOIN sys.sysobjects oConstraint
    INNER JOIN sys.sysobjects oParent
    INNER JOIN sys.all_columns oParentCol
            ON FKC.parent_object_id=oParentCol.object_id /* ID of the object to which this column belongs.*/
            AND FKC.parent_column_id=oParentCol.column_id/* ID of the column. Is unique within the object.Column IDs might not be sequential.*/
    INNER JOIN sys.sysobjects oReference
    INNER JOIN sys.all_columns oReferenceCol
            ON FKC.referenced_object_id=oReferenceCol.object_id /* ID of the object to which this column belongs.*/
            AND FKC.referenced_column_id=oReferenceCol.column_id/* ID of the column. Is unique within the object.Column IDs might not be sequential.*/


select * from   ALL_KEYS_IN_TABLE

For reference please read thru -

Convert numpy array to tuple

Here's a function that'll do it:

def totuple(a):
        return tuple(totuple(i) for i in a)
    except TypeError:
        return a

And an example:

>>> array = numpy.array(((2,2),(2,-2)))
>>> totuple(array)
((2, 2), (2, -2))

How to click a href link using Selenium

You can use this method:

For the links if you use linkText(); it is more effective than the any other locator.

driver.findElement(By.linkText("App Configuration")).click();

Find all packages installed with easy_install/pip?

As @almenon pointed out, this no longer works and it is not the supported way to get package information in your code. The following raises an exception:

import pip
installed_packages = dict([(package.project_name, package.version) 
                           for package in pip.get_installed_distributions()])

To accomplish this, you can import pkg_resources. Here's an example:

import pkg_resources
installed_packages = dict([(package.project_name, package.version)
                           for package in pkg_resources.working_set])

I'm on v3.6.5

How does the ARM architecture differ from x86?

The ARM is like an Italian sports car:

  • Well balanced, well tuned, engine. Gives good acceleration, and top speed.
  • Excellent chases, brakes and suspension. Can stop quickly, can corner without slowing down.

The x86 is like an American muscle car:

  • Big engine, big fuel pump. Gives excellent top speed, and acceleration, but uses a lot of fuel.
  • Dreadful brakes, you need to put an appointment in your diary, if you want to slowdown.
  • Terrible steering, you have to slow down to corner.

In summary: the x86 is based on a design from 1974 and is good in a straight line (but uses a lot of fuel). The arm uses little fuel, does not slowdown for corners (branches).

Metaphor over, here are some real differences.

  • Arm has more registers.
  • Arm has few special purpose registers, x86 is all special purpose registers (so less moving stuff around).
  • Arm has few memory access commands, only load/store register.
  • Arm is internally Harvard architecture my design.
  • Arm is simple and fast.
  • Arm instructions are architecturally single cycle (except load/store multiple).
  • Arm instructions often do more than one thing (in a single cycle).
  • Where more that one Arm instruction is needed, such as the x86's looping store & auto-increment, the Arm still does it in less clock cycles.
  • Arm has more conditional instructions.
  • Arm's branch predictor is trivially simple (if unconditional or backwards then assume branch, else assume not-branch), and performs better that the very very very complex one in the x86 (there is not enough space here to explain it, not that I could).
  • Arm has a simple consistent instruction set (you could compile by hand, and learn the instruction set quickly).

How to convert a column of DataTable to a List

I do just like below, after you set your column AsEnumarable you can sort, order or how you want.

 _dataTable.AsEnumerable().Select(p => p.Field<string>("ColumnName")).ToList();

How to run a task when variable is undefined in ansible?

As per latest Ansible Version 2.5, to check if a variable is defined and depending upon this if you want to run any task, use undefined keyword.

    - shell: echo "I've got '{{ foo }}' and am not afraid to use it!"
      when: foo is defined

    - fail: msg="Bailing out. this play requires 'bar'"
      when: bar is undefined

Ansible Documentation

How to position two elements side by side using CSS

Use either float or inline elements:

Example JSBIN


<!DOCTYPE html>
<meta charset=utf-8 />
<title>JS Bin</title>
  <div>float example</div>
  <div><div style="float:left">Floating left content</div><div>Some content</div></div>
  <div>inline block example</div>
  <div><div style="display:inline-block">Some content</div><div style="display:inline-block">Next content</div></div>

android: how to align image in the horizontal center of an imageview?

Your ImageView has the attribute wrap_content. I would think that the Image is centered inside the imageview but the imageview itself is not centered in the parentview. If you have only the imageview on the screen try match_parent instead of wrap_content. If you have more then one view in the layout you have to center the imageview.

Multiple file extensions in OpenFileDialog

Based on First answer here is the complete image selection options:

Filter = @"|All Image Files|*.BMP;*.bmp;*.JPG;*.JPEG*.jpg;*.jpeg;*.PNG;*.png;*.GIF;*.gif;*.tif;*.tiff;*.ico;*.ICO

Could not transfer artifact org.apache.maven.plugins:maven-surefire-plugin:pom:2.7.1 from/to central (

If you are not behind any proxy and still getting connection timeout error, please check firewall settings/ antivirus. Sometimes firewall may block the connectivity from any tool (like Eclipse/STS etc..)

Load view from an external xib file in storyboard

My full example is here, but I will provide a summary below.


Add a .swift and .xib file each with the same name to your project. The .xib file contains your custom view layout (using auto layout constraints preferably).

Make the swift file the xib file's owner.

enter image description here Code

Add the following code to the .swift file and hook up the outlets and actions from the .xib file.

import UIKit
class ResuableCustomView: UIView {

    let nibName = "ReusableCustomView"
    var contentView: UIView?

    @IBOutlet weak var label: UILabel!
    @IBAction func buttonTap(_ sender: UIButton) {
        label.text = "Hi"

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

        guard let view = loadViewFromNib() else { return }
        view.frame = self.bounds
        contentView = view

    func loadViewFromNib() -> UIView? {
        let bundle = Bundle(for: type(of: self))
        let nib = UINib(nibName: nibName, bundle: bundle)
        return nib.instantiate(withOwner: self, options: nil).first as? UIView

Use it

Use your custom view anywhere in your storyboard. Just add a UIView and set the class name to your custom class name.

enter image description here

For a while Christopher Swasey's approach was the best approach I had found. I asked a couple of the senior devs on my team about it and one of them had the perfect solution! It satisfies every one of the concerns that Christopher Swasey so eloquently addressed and it doesn't require boilerplate subclass code(my main concern with his approach). There is one gotcha, but other than that it is fairly intuitive and easy to implement.

  1. Create a custom UIView class in a .swift file to control your xib. i.e. MyCustomClass.swift
  2. Create a .xib file and style it as you want. i.e. MyCustomClass.xib
  3. Set the File's Owner of the .xib file to be your custom class (MyCustomClass)
  4. GOTCHA: leave the class value (under the identity Inspector) for your custom view in the .xib file blank. So your custom view will have no specified class, but it will have a specified File's Owner.
  5. Hook up your outlets as you normally would using the Assistant Editor.
    • NOTE: If you look at the Connections Inspector you will notice that your Referencing Outlets do not reference your custom class (i.e. MyCustomClass), but rather reference File's Owner. Since File's Owner is specified to be your custom class, the outlets will hook up and work propery.
  6. Make sure your custom class has @IBDesignable before the class statement.
  7. Make your custom class conform to the NibLoadable protocol referenced below.
    • NOTE: If your custom class .swift file name is different from your .xib file name, then set the nibName property to be the name of your .xib file.
  8. Implement required init?(coder aDecoder: NSCoder) and override init(frame: CGRect) to call setupFromNib() like the example below.
  9. Add a UIView to your desired storyboard and set the class to be your custom class name (i.e. MyCustomClass).
  10. Watch IBDesignable in action as it draws your .xib in the storyboard with all of it's awe and wonder.

Here is the protocol you will want to reference:

public protocol NibLoadable {
    static var nibName: String { get }

public extension NibLoadable where Self: UIView {

    public static var nibName: String {
        return String(describing: Self.self) // defaults to the name of the class implementing this protocol.

    public static var nib: UINib {
        let bundle = Bundle(for: Self.self)
        return UINib(nibName: Self.nibName, bundle: bundle)

    func setupFromNib() {
        guard let view = Self.nib.instantiate(withOwner: self, options: nil).first as? UIView else { fatalError("Error loading \(self) from nib") }
        view.translatesAutoresizingMaskIntoConstraints = false
        view.leadingAnchor.constraint(equalTo: self.safeAreaLayoutGuide.leadingAnchor, constant: 0).isActive = true
        view.topAnchor.constraint(equalTo: self.safeAreaLayoutGuide.topAnchor, constant: 0).isActive = true
        view.trailingAnchor.constraint(equalTo: self.safeAreaLayoutGuide.trailingAnchor, constant: 0).isActive = true
        view.bottomAnchor.constraint(equalTo: self.safeAreaLayoutGuide.bottomAnchor, constant: 0).isActive = true

And here is an example of MyCustomClass that implements the protocol (with the .xib file being named MyCustomClass.xib):

class MyCustomClass: UIView, NibLoadable {

    @IBOutlet weak var myLabel: UILabel!

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

    override init(frame: CGRect) {
        super.init(frame: frame)


NOTE: If you miss the Gotcha and set the class value inside your .xib file to be your custom class, then it will not draw in the storyboard and you will get a EXC_BAD_ACCESS error when you run the app because it gets stuck in an infinite loop of trying to initialize the class from the nib using the init?(coder aDecoder: NSCoder) method which then calls Self.nib.instantiate and calls the init again.

How to clear/delete the contents of a Tkinter Text widget?

for me "1.0" didn't work, but '0' worked. This is Python 2.7.12, just FYI. Also depends on how you import the module. Here's how:

import Tkinter as tk
window = tk.Tk()
textBox = tk.Entry(window)

And the following code is called when you need to clear it. In my case there was a button Save that saves the data from the Entry text box and after the button is clicked, the text box is cleared


RegEx pattern any two letters followed by six numbers

I depends on what is the regexp language you use, but informally, it would be:


where [:alpha:] = [a-zA-Z] and [:digit:] = [0-9]

If you use a regexp language that allows finite repetitions, that would look like:


The correct syntax depends on the particular language you're using, but that is the idea.

How to query first 10 rows and next time query other 10 rows from table


    $conn = mysqli_connect('localhost','root','','northwind');
    $data_per_page = 10;
    $select = "SELECT * FROM `customers`";  
    $select_run = mysqli_query($conn, $select);
    $records = mysqli_num_rows($select_run);
    // while ($result = mysqli_fetch_array($select_run)) {      
    //     echo $result['CompanyName'] . '<br>';        
    // }
    // $records;
    echo "<br>";
    $no_of_page = ceil($records / $data_per_page);
        $page = 1;
        $page = $_GET['page'];
    $page_limit_data = ($page - 1) * 10;
    $select = "SELECT * FROM customers LIMIT " . $page_limit_data . ',' . $data_per_page ;
    $select_run = mysqli_query($conn, $select);
    while ($row_select = mysqli_fetch_array($select_run)){
        echo $row_select['CompanyName'] . '<br>' ;
    for($page=1; $page<= $no_of_page; $page++){ 
        echo "<a href='pagination.php?page=$page'> $page" . ', ';   
<h1> Testing Limit Functions Here  </h1>
$limit = "SELECT CompanyName From customers LIMIT 10 OFFSET 5";
$limit_run = mysqli_query($conn , $limit);
while($limit_result = mysqli_fetch_array($limit_run)){
    echo $limit_result['CompanyName'] . '<br>';

Laravel blade check empty foreach

I think you are trying to check whether the array is empty or not.You can do like this :

     // $result is not empty
    // $result is empty

Reference isEmpty()

How to change RGB color to HSV?

The EasyRGB has many color space conversions. Here is the code for the RGB->HSV conversion.

What is the "assert" function?

It is a function that will halt program execution if the value it has evaluated is false. Usually it is surrounded by a macro so that it is not compiled into the resultant binary when compiled with release settings.

It is designed to be used for testing the assumptions you have made. For example:

void strcpy(char* dest, char* src){
    //pointers shouldn't be null

    //copy string
    while(*dest++ = *src++);

The ideal you want is that you can make an error in your program, like calling a function with invalid arguments, and you hit an assert before it segfaults (or fails to work as expected)

What exactly does a jar file contain?

Jar( Java Archive) contains group of .class files.

1.To create Jar File (Zip File)

 if one .class (say, Demo.class) then use command jar -cvf NameOfJarFile.jar Demo.class (usually it’s not feasible for only one .class file)

 if more than one .class (say, Demo.class , DemoOne.class) then use command jar -cvf NameOfJarFile.jar Demo.class DemoOne.class

 if all .class is to be group (say, Demo.class , DemoOne.class etc) then use command jar -cvf NameOfJarFile.jar *.class

2.To extract Jar File (Unzip File)

    jar -xvf NameOfJarFile.jar

3.To display table of content

    jar -tvf NameOfJarFile.jar

How do I define global variables in CoffeeScript?

You can pass -b option when you compile code via coffee-script under node.js. The compiled code will be the same as on

Breaking to a new line with inline-block?

Remove all br tags and use display: table.

.text span {
   background: rgba(165, 220, 79, 0.8);
   display: table;
   padding: 7px 10px;
   color: white;
.fullscreen .large { font-size: 80px }

Explanation: The table wraps the width of its content by default without setting a width, but is still a block level element. You can get the same behavior by setting a width to other block-level elements:

<span style="display:block;border:1px solid red;width:100px;">Like a default table.</span>

Notice the <code> element doesn't flow inline with the <span> like it would normally. Check it out with the computed styles in your dev tools. You'll see pseudo margin to the right of the <span>. Anyway, this is the same as the table, but the table has the added benefit of always forming to the width of its content.

CSS how to make scrollable list

Another solution would be as below where the list is placed under a drop-down button.

  <button class="btn dropdown-toggle btn-primary btn-sm" data-toggle="dropdown"
    >Markets<span class="caret"></span></button>

    <ul class="dropdown-menu", style="height:40%; overflow:hidden; overflow-y:scroll;">
      {{ }}

Chrome, Javascript, in new tab

You can use this code to open in new tab..

function openWindow( url )
{, '_blank');

I got it from stackoverflow..

How to convert timestamps to dates in Bash?

In this answer I copy Dennis Williamson's answer and modify it slightly to allow a vast speed increase when piping a column of many timestamps to the script. For example, piping 1000 timestamps to the original script with xargs -n1 on my machine took 6.929s as opposed to 0.027s with this modified version:

if [[ -z "$1" ]]
    if [[ -p /dev/stdin ]]    # input from a pipe
        cat - | gawk '{ print strftime("%c", $1); }'
        echo "No timestamp given." >&2
    date -d @$1 +%c