Programs & Examples On #Datamodel

According to Hoberman (2009), "A data model is a wayfinding tool for both business and IT professionals, which uses a set of symbols and text to precisely explain a subset of real information to improve communication within the organization and thereby lead to a more flexible and stable application environment.

Create a new object from type parameter in generic class

Because the compiled JavaScript has all the type information erased, you can't use T to new up an object.

You can do this in a non-generic way by passing the type into the constructor.

class TestOne {
    hi() {

class TestTwo {
    constructor(private testType) {

    getNew() {
        return new this.testType();

var test = new TestTwo(TestOne);

var example = test.getNew();

You could extend this example using generics to tighten up the types:

class TestBase {
    hi() {
        alert('Hi from base');

class TestSub extends TestBase {
    hi() {
        alert('Hi from sub');

class TestTwo<T extends TestBase> {
    constructor(private testType: new () => T) {

    getNew() : T {
        return new this.testType();

//var test = new TestTwo<TestBase>(TestBase);
var test = new TestTwo<TestSub>(TestSub);

var example = test.getNew();

Difference between __getattr__ vs __getattribute__

This is just an example based on Ned Batchelder's explanation.

__getattr__ example:

class Foo(object):
    def __getattr__(self, attr):
        print "looking up", attr
        value = 42
        self.__dict__[attr] = value
        return value

f = Foo()
print f.x 
#output >>> looking up x 42

f.x = 3
print f.x 
#output >>> 3

print ('__getattr__ sets a default value if undefeined OR __getattr__ to define how to handle attributes that are not found')

And if same example is used with __getattribute__ You would get >>> RuntimeError: maximum recursion depth exceeded while calling a Python object

How do I correctly clean up a Python object?

Just wrap your destructor with a try/except statement and it will not throw an exception if your globals are already disposed of.


Try this:

from weakref import proxy

class MyList(list): pass

class Package:
    def __init__(self):
        self.__del__.im_func.files = MyList([1,2,3,4])
        self.files = proxy(self.__del__.im_func.files)

    def __del__(self):
        print self.__del__.im_func.files

It will stuff the file list in the del function that is guaranteed to exist at the time of call. The weakref proxy is to prevent Python, or yourself from deleting the self.files variable somehow (if it is deleted, then it will not affect the original file list). If it is not the case that this is being deleted even though there are more references to the variable, then you can remove the proxy encapsulation.

Usage of __slots__?

In addition to the other answers, here is an example of using __slots__:

>>> class Test(object):   #Must be new-style class!
...  __slots__ = ['x', 'y']
>>> pt = Test()
>>> dir(pt)
['__class__', '__delattr__', '__doc__', '__getattribute__', '__hash__', 
 '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', 
 '__repr__', '__setattr__', '__slots__', '__str__', 'x', 'y']
>>> pt.x
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: x
>>> pt.x = 1
>>> pt.x
>>> pt.z = 2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'Test' object has no attribute 'z'
>>> pt.__dict__
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'Test' object has no attribute '__dict__'
>>> pt.__slots__
['x', 'y']

So, to implement __slots__, it only takes an extra line (and making your class a new-style class if it isn't already). This way you can reduce the memory footprint of those classes 5-fold, at the expense of having to write custom pickle code, if and when that becomes necessary.

Python object.__repr__(self) should be an expression?

Guideline: If you can succinctly provide an exact representation, format it as a Python expression (which implies that it can be both eval'd and copied directly into source code, in the right context). If providing an inexact representation, use <...> format.

There are many possible representations for any value, but the one that's most interesting for Python programmers is an expression that recreates the value. Remember that those who understand Python are the target audience—and that's also why inexact representations should include relevant context. Even the default <XXX object at 0xNNN>, while almost entirely useless, still provides type, id() (to distinguish different objects), and indication that no better representation is available.

md-table - How to update the column width

.mat-column-skills {
    max-width: 40px;

How to fix Python Numpy/Pandas installation?

If you're like me and you don't like the idea of deleting things that were part of the standard system installation (which others have suggested) then you might like the solution I ended up using:

  1. Get Homebrew - it's a one-line shell script to install!
  2. Edit your .profile, or whatever is appropriate, and put /usr/local/bin at the start of your PATH so that Homebrew binaries are found before system binaries
  3. brew install python - this installs a newer version of python in /usr/local
  4. pip install pandas

This worked for me in OS X 10.8.2, and I can't see any reason it shouldn't work in 10.6.8.

Adding a dictionary to another

The most obvious way is:

foreach(var kvp in NewAnimals)
   Animals.Add(kvp.Key, kvp.Value); 
  //use Animals[kvp.Key] = kvp.Value instead if duplicate keys are an issue

Since Dictionary<TKey, TValue>explicitly implements theICollection<KeyValuePair<TKey, TValue>>.Addmethod, you can also do this:

var animalsAsCollection = (ICollection<KeyValuePair<string, string>>) Animals;

foreach(var kvp in NewAnimals)

It's a pity the class doesn't have anAddRangemethod likeList<T> does.

VBA equivalent to Excel's mod function

You want the mod operator.

The expression a Mod b is equivalent to the following formula:

a - (b * (a \ b))

Edited to add:

There are some special cases you may have to consider, because Excel is using floating point math (and returns a float), which the VBA function returns an integer. Because of this, using mod with floating-point numbers may require extra attention:

  • Excel's results may not correspond exactly with what you would predict; this is covered briefly here (see topmost answer) and at great length here.

  • As @André points out in the comments, negative numbers may round in the opposite direction from what you expect. The Fix() function he suggests is explained here (MSDN).

How to grant remote access permissions to mysql server for user?

Two steps:

  1. set up user with wildcard:
    create user 'root'@'%' identified by 'some_characters'; GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY PASSWORD 'some_characters' WITH GRANT OPTION

  2. vim /etc/my.cnf
    add the following:

restart server, you should not have any problem connecting to it.

How does the data-toggle attribute work? (What's its API?)

I think you are a bit confused on the purpose of custom data attributes. From the w3 spec

Custom data attributes are intended to store custom data private to the page or application, for which there are no more appropriate attributes or elements.

By itself an attribute of data-toggle=value is basically a key-value pair, in which the key is "data-toggle" and the value is "value".

In the context of Bootstrap, the custom data in the attribute is almost useless without the context that their JavaScript library includes for the data. If you look at the non-minified version of bootstrap.js then you can do a search for "data-toggle" and find how it is being used.

Here is an example of Bootstrap JavaScript code that I copied straight from the file regarding the use of "data-toggle".

  • Button Toggle

    Button.prototype.toggle = function () {
      var changed = true
      var $parent = this.$element.closest('[data-toggle="buttons"]')
      if ($parent.length) {
        var $input = this.$element.find('input')
        if ($input.prop('type') == 'radio') {
          if ($input.prop('checked') && this.$element.hasClass('active')) changed = false
          else $parent.find('.active').removeClass('active')
        if (changed) $input.prop('checked', !this.$element.hasClass('active')).trigger('change')
      } else {
        this.$element.attr('aria-pressed', !this.$element.hasClass('active'))
      if (changed) this.$element.toggleClass('active')

The context that the code provides shows that Bootstrap is using the data-toggle attribute as a custom query selector to process the particular element.

From what I see these are the data-toggle options:

  • collapse
  • dropdown
  • modal
  • tab
  • pill
  • button(s)

You may want to look at the Bootstrap JavaScript documentation to get more specifics of what each do, but basically the data-toggle attribute toggles the element to active or not.

Javascript find json value

Making more general the @showdev answer.

var getObjectByValue = function (array, key, value) {
    return array.filter(function (object) {
        return object[key] === value;


getObjectByValue(data, "code", "DZ" );

Django download a file

I use this method:

{% if quote.myfile %}
    <div class="">
        <a role="button" 
            href="{{ quote.myfile.url }}"
            download="{{ quote.myfile.url }}"
            class="btn btn-light text-dark ml-0">
            Download attachment
{% endif %}

php - How do I fix this illegal offset type error

I had a similar problem. As I got a Character from my XML child I had to convert it first to a String (or Integer, if you expect one). The following shows how I solved the problem.

foreach($xml->children() as $newInstr){
        $iInstrument = new Instrument($newInstr['id'],$newInstr->Naam,$newInstr->Key);
        $arrInstruments->offsetSet((String)$iInstrument->getID(), $iInstrument);

how to fix stream_socket_enable_crypto(): SSL operation failed with code 1

Reading app/config/mailphp

Supported : "smtp", "mail", "sendmail"

Depending on your mail utilities installed on your machine, fill in the value of the driver key. I would do

'driver' => 'sendmail',

ASP.NET Custom Validator Client side & Server Side validation not firing

Use this:

<asp:CustomValidator runat="server" id="vld" ValidateEmptyText="true"/>

To validate an empty field.

You don't need to add 2 validators !

Microsoft Visual C++ Compiler for Python 3.4

For the different python versions:

Visual C++ |CPython
14.0       |3.5
10.0       |3.3, 3.4
9.0        |2.6, 2.7, 3.0, 3.1, 3.2

Source: Windows Compilers for py

Also refer: this answer

How to get First and Last record from a sql query?

    MIN(Column), MAX(Column), UserId 
    UserId DESC




    TableName AS Tablename1

How to center a (background) image within a div?

If your background image is a vertically aligned sprite sheet, you can horizontally center each sprite like this:

#doit {
    background-image: url('images/pic.png'); 
    background-repeat: none;
    background-position: 50% [y position of sprite];

If your background image is a horizontally aligned sprite sheet, you can vertically center each sprite like this:

#doit {
    background-image: url('images/pic.png'); 
    background-repeat: none;
    background-position: [x position of sprite] 50%;

If your sprite sheet is compact, or you are not trying to center your background image in one of the aforementioned scenarios, these solutions do not apply.

Passing parameters in rails redirect_to

redirect_to new_user_path(:id => 1, :contact_id => 3, :name => 'suleman')

WARNING in budgets, maximum exceeded for initial

Open angular.json file and find budgets keyword.

It should look like:

    "budgets": [
          "type": "initial",
          "maximumWarning": "2mb",
          "maximumError": "5mb"

As you’ve probably guessed you can increase the maximumWarning value to prevent this warning, i.e.:

    "budgets": [
          "type": "initial",
          "maximumWarning": "4mb", <===
          "maximumError": "5mb"

What does budgets mean?

A performance budget is a group of limits to certain values that affect site performance, that may not be exceeded in the design and development of any web project.

In our case budget is the limit for bundle sizes.

See also:

SSH Key: “Permissions 0644 for '' are too open.” on mac

After running below command it works for me

sudo chmod 600 /path/to/my/key.pem

Link to the issue number on GitHub within a commit message

You can also cross reference repos:


xxx being the issue number

Why does make think the target is up to date?

EDIT: This only applies to some versions of make - you should check your man page.

You can also pass the -B flag to make. As per the man page, this does:

-B, --always-make Unconditionally make all targets.

So make -B test would solve your problem if you were in a situation where you don't want to edit the Makefile or change the name of your test folder.

INSERT SELECT statement in Oracle 11G

Get rid of the values keyword and the parens. You can see an example here.

This is basic INSERT syntax:

INSERT INTO "table_name" ("column1", "column2", ...)
VALUES ("value1", "value2", ...);

This is the INSERT SELECT syntax:

INSERT INTO "table1" ("column1", "column2", ...)
SELECT "column3", "column4", ...
FROM "table2";

Effective swapping of elements of an array in Java

If you're swapping numbers and want a concise way to write the code without creating a separate function or using a confusing XOR hack, I find this is much easier to understand and it's also a one liner.

public static void swap(int[] arr, int i, int j) {
    arr[i] = (arr[i] + arr[j]) - (arr[j] = arr[i]);

What I've seen from some primitive benchmarks is that the performance difference is basically negligible as well.

This is one of the standard ways for swapping array elements without using a temporary variable, at least for integers.

trying to animate a constraint in swift

In my case, I only updated the custom view.

customView.layoutIfNeeded()    // Change to view.layoutIfNeeded()
UIView.animate(withDuration: 0.5) {
   customViewConstraint.constant = 100.0
   customView.layoutIfNeeded() // Change to view.layoutIfNeeded()

Unsupported operand type(s) for +: 'int' and 'str'


str_list = " ".join([str(ele) for ele in numlist])

this statement will give you each element of your list in string format

print("The list now looks like [{0}]".format(str_list))


change print(numlist.pop(2)+" has been removed") to

print("{0} has been removed".format(numlist.pop(2)))

as well.

How to query between two dates using Laravel and Eloquent?

I know this might be an old question but I just found myself in a situation where I had to implement this feature in a Laravel 5.7 app. Below is what worked from me.

 $articles = Articles::where("created_at",">", Carbon::now()->subMonths(3))->get();

You will also need to use Carbon

use Carbon\Carbon;

Hide axis and gridlines Highcharts

you can also hide the gridline on yAxis as:

  gridLineWidth: 0,
  minorGridLineWidth: 0

How does Google reCAPTCHA v2 work behind the scenes?

May I present my guess, since this is not a open technology.

Google says it's about combing information from before, during, after to distinguish human from robot. But I am more interested about that final click on the check box.

Say, the POST data (solved CAPTCHA) has a field called fingerprint, a string calculated from user behavior. I think there may be a field about that check box location. I guess this check box is in a coordinate system randomly generated by Google back-end and encrypted by the public key of my site. So, a robot may "guess/calculate" a location about this box, but when site owner makes the GET query with private key to verify user identity, Google will decrypt the coordinate system and say if the user click on the right place. So, only one possible right click(with some offsets, it's a square box) location in this random coordinate system owned by only Google and site owners.

HTML-parser on Node.js

If you want to build DOM you can use jsdom.

There's also cheerio, it has the jQuery interface and it's a lot faster than older versions of jsdom, although these days they are similar in performance.

You might wanna have a look at htmlparser2, which is a streaming parser, and according to its benchmark, it seems to be faster than others, and no DOM by default. It can also produce a DOM, as it is also bundled with a handler that creates a DOM. This is the parser that is used by cheerio.

parse5 also looks like a good solution. It's fairly active (11 days since the last commit as of this update), WHATWG-compliant, and is used in jsdom, Angular, and Polymer.

And if you want to parse HTML for web scraping, you can use YQL1. There is a node module for it. YQL I think would be the best solution if your HTML is from a static website, since you are relying on a service, not your own code and processing power. Though note that it won't work if the page is disallowed by the robot.txt of the website, YQL won't work with it.

If the website you're trying to scrape is dynamic then you should be using a headless browser like phantomjs. Also have a look at casperjs, if you're considering phantomjs. And you can control casperjs from node with SpookyJS.

Beside phantomjs there's zombiejs. Unlike phantomjs that cannot be embedded in nodejs, zombiejs is just a node module.

There's a nettuts+ toturial for the latter solutions.

1 Since Aug. 2014, YUI library, which is a requirement for YQL, is no longer actively maintained, source

how to clear the screen in python

If you mean the screen where you have that interpreter prompt >>> you can do CTRL+L on Bash shell can help. Windows does not have equivalent. You can do

import os
os.system('cls')  # on windows


os.system('clear')  # on linux / os x

What does the 'standalone' directive mean in XML?

  • The standalone directive is an optional attribute on the XML declaration.
  • Valid values are yes and no, where no is the default value.
  • The attribute is only relevant when a DTD is used. (The attribute is irrelevant when using a schema instead of a DTD.)
  • standalone="yes" means that the XML processor must use the DTD for validation only. In that case it will not be used for:
    • default values for attributes
    • entity declarations
    • normalization
  • Note that standalone="yes" may add validity constraints if the document uses an external DTD. When the document contains things that would require modification of the XML, such as default values for attributes, and standalone="yes" is used then the document is invalid.
  • standalone="yes" may help to optimize performance of document processing.

Source: The standalone pseudo-attribute is only relevant if a DTD is used

Immutable vs Mutable types

I haven't read all the answers, but the selected answer is not correct and I think the author has an idea that being able to reassign a variable means that whatever datatype is mutable. That is not the case. Mutability has to do with passing by reference rather than passing by value.

Lets say you created a List

a = [1,2]

If you were to say:

b = a
b[1] = 3

Even though you reassigned a value on B, it will also reassign the value on a. Its because when you assign "b = a". You are passing the "Reference" to the object rather than a copy of the value. This is not the case with strings, floats etc. This makes list, dictionaries and the likes mutable, but booleans, floats etc immutable.

How can I use delay() with show() and hide() in Jquery

Pass a duration to show() and hide():

When a duration is provided, .show() becomes an animation method.

E.g. element.delay(1000).show(0)


Redirect form to different URL based on select option element

This can be archived by adding code on the onchange event of the select control.

For Example:

<select onchange="this.options[this.selectedIndex].value && (window.location = this.options[this.selectedIndex].value);">
    <option value="">Gmail</option>
    <option value="">Youtube</option>

Eclipse comment/uncomment shortcut?

Ctrl + 7 to comment a selected text.

Return HTML content as a string, given URL. Javascript Function

In some websites, XMLHttpRequest may send you something like <script src="#"></srcipt>. In that case, try using a HTML document like the script under:

    <iframe src=""></iframe>
    <script src="your_JS"></script>

Now you can use JS to get some text out of the HTML, such as getElementbyId.

But this may not work for some websites with cross-domain blocking.

Qt Creator color scheme

Linux, Qt Creator >= 3.4:

You could edit theese themes:


Why does my sorting loop seem to append an element where it shouldn't?

Apart from the alternative solutions that were posted here (which are correct), no one has actually answered your question by addressing what was wrong with your code.

It seems as though you were trying to implement a selection sort algorithm. I will not go into the details of how sorting works here, but I have included a few links for your reference =)

Your code was syntactically correct, but logically wrong. You were partially sorting your strings by only comparing each string with the strings that came after it. Here is a corrected version (I retained as much of your original code to illustrate what was "wrong" with it):

static  String Array[]={" Hello " , " This " , "is ", "Sorting ", "Example"};
String  temp;

//Keeps track of the smallest string's index
int  shortestStringIndex; 

public static void main(String[] args)  

 //I reduced the upper bound from Array.length to (Array.length - 1)
 for(int j=0; j < Array.length - 1;j++)
     shortestStringIndex = j;

     for (int i=j+1 ; i<Array.length; i++)
         //We keep track of the index to the smallest string
             shortestStringIndex = i;  
     //We only swap with the smallest string
     if(shortestStringIndex != j)
         String temp = Array[j];
         Array[j] = Array[shortestStringIndex]; 
         Array[shortestStringIndex] = temp;

Further Reading

The problem with this approach is that its asymptotic complexity is O(n^2). In simplified words, it gets very slow as the size of the array grows (approaches infinity). You may want to read about better ways to sort data, such as quicksort.

How to create an array for JSON using PHP?



    $user="select * from tbl_registration where member_id= '".$username."' ";
    $rsuser = $obj->select($user);
        //   (Status if 2 then its expire)    (1= use) ( 0 = not use)

        $cheknew="select name,ldate,offer_photo  from tbl_offer where status=1 ";
        $rscheknew = $obj->selectjson($cheknew);


            echo "{\"status\" : \"200\" ,\"responce\" : \"201\", \"message\" : \"Get Record\",\"feed\":".str_replace("<p>","",$nik). "}";
            $row2="No Record Found";
            echo "{\"status\" : \"202\",  \"responce\" : \"604\",\"message\" : \"No Record Found \",\"feed\":".str_replace("<p>","",$nik1). "}";
        $row2="Invlid User";
        echo "{\"status\" : \"404\", \"responce\" : \"602\",\"message\" : \"Invlid User \",\"feed\":".str_replace("<p>","",$nik1). "}";


What does if __name__ == "__main__": do?

It is a special for when a Python file is called from the command line. This is typically used to call a "main()" function or execute other appropriate startup code, like commandline arguments handling for instance.

It could be written in several ways. Another is:

def some_function_for_instance_main():

__name__ == '__main__' and some_function_for_instance_main()

I am not saying you should use this in production code, but it serves to illustrate that there is nothing "magical" about if __name__ == '__main__'. It is a good convention for invoking a main function in Python files.

Accessing an SQLite Database in Swift

I've created an elegant SQLite library written completely in Swift called SwiftData.

Some of its feature are:

  • Bind objects conveniently to the string of SQL
  • Support for transactions and savepoints
  • Inline error handling
  • Completely thread safe by default

It provides an easy way to execute 'changes' (e.g. INSERT, UPDATE, DELETE, etc.):

if let err = SD.executeChange("INSERT INTO Cities (Name, Population, IsWarm, FoundedIn) VALUES ('Toronto', 2615060, 0, '1793-08-27')") {
    //there was an error during the insert, handle it here
} else {
    //no error, the row was inserted successfully

and 'queries' (e.g. SELECT):

let (resultSet, err) = SD.executeQuery("SELECT * FROM Cities")
if err != nil {
    //there was an error during the query, handle it here
} else {
    for row in resultSet {
        if let name = row["Name"].asString() {
            println("The City name is: \(name)")
        if let population = row["Population"].asInt() {
            println("The population is: \(population)")
        if let isWarm = row["IsWarm"].asBool() {
            if isWarm {
                println("The city is warm")
            } else {
                println("The city is cold")
        if let foundedIn = row["FoundedIn"].asDate() {
            println("The city was founded in: \(foundedIn)")

Along with many more features!

You can check it out here

Java SSLHandshakeException "no cipher suites in common"

It looks like you are trying to connect using TLSv1.2, which isn't widely implemented on servers. Does your destination support tls1.2?

Android ListView selected item stay highlighted

Use the id instead:

This is the easiest method that can handle even if the list is long:

public View getView(final int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
    Holder holder=new Holder();
    View rowView;
    rowView = inflater.inflate(R.layout.list_item, null);
    //Handle your items.
    //StringHolder.mSelectedItem is a public static variable.

    return rowView;

And then in your onclicklistener:

list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
            StringHolder.mSelectedItem = catagoryAdapter.getItemId(i-1);

Java8: sum values from specific field of the objects in a list


int sum = -> o.field > 10).mapToInt(o -> o.field).sum();

open the file upload dialogue box onclick the image

<input type="file" id="imgupload" style="display:none"/>
<label for='imgupload'> <button id="OpenImgUpload">Image Upload</button></label>

On click of for= attribute will automatically focus on "file input" and upload dialog box will open

How do I get client IP address in ASP.NET CORE?

I found that, some of you found that the IP address you get is :::1 or

This is the problem because of you try to get IP from your own machine, and the confusion of C# that try to return IPv6.

So, I implement the answer from @Johna ( and @David (, Thanks to them!

and here to solution:

  1. add Microsoft.AspNetCore.HttpOverrides Package in your References (Dependencies/Packages)

  2. add this line in Startup.cs

    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        // your current code
        // start code to add
        // to get ip address
        app.UseForwardedHeaders(new ForwardedHeadersOptions
        ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto
        // end code to add
  3. to get IPAddress, use this code in any of your Controller.cs

    IPAddress remoteIpAddress = Request.HttpContext.Connection.RemoteIpAddress;
    string result = "";
    if (remoteIpAddress != null)
        // If we got an IPV6 address, then we need to ask the network for the IPV4 address 
        // This usually only happens when the browser is on the same machine as the server.
        if (remoteIpAddress.AddressFamily == System.Net.Sockets.AddressFamily.InterNetworkV6)
            remoteIpAddress = System.Net.Dns.GetHostEntry(remoteIpAddress).AddressList
    .First(x => x.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork);
        result = remoteIpAddress.ToString();

and now you can get IPv4 address from remoteIpAddress or result

Using '<%# Eval("item") %>'; Handling Null Value and showing 0 against

I use the following for VB.Net:

<%# If(Eval("item").ToString() Is DBNull.Value, "0 value", Eval("item")) %>

What is the proper way to format a multi-line dict in Python?

Generally, you would not include the comma after the final entry, but Python will correct that for you.

unique combinations of values in selected columns in pandas data frame and count

You can groupby on cols 'A' and 'B' and call size and then reset_index and rename the generated column:

In [26]:

     A    B  count
0   no   no      1
1   no  yes      2
2  yes   no      4
3  yes  yes      3


A little explanation, by grouping on the 2 columns, this groups rows where A and B values are the same, we call size which returns the number of unique groups:


A    B  
no   no     1
     yes    2
yes  no     4
     yes    3
dtype: int64

So now to restore the grouped columns, we call reset_index:


     A    B  0
0   no   no  1
1   no  yes  2
2  yes   no  4
3  yes  yes  3

This restores the indices but the size aggregation is turned into a generated column 0, so we have to rename this:


     A    B  count
0   no   no      1
1   no  yes      2
2  yes   no      4
3  yes  yes      3

groupby does accept the arg as_index which we could have set to False so it doesn't make the grouped columns the index, but this generates a series and you'd still have to restore the indices and so on....:

df1.groupby(['A','B'], as_index=False).size()

A    B  
no   no     1
     yes    2
yes  no     4
     yes    3
dtype: int64

Build .NET Core console application to output an EXE

For debugging purposes, you can use the DLL file. You can run it using dotnet ConsoleApp2.dll. If you want to generate an EXE file, you have to generate a self-contained application.

To generate a self-contained application (EXE in Windows), you must specify the target runtime (which is specific to the operating system you target).

Pre-.NET Core 2.0 only: First, add the runtime identifier of the target runtimes in the .csproj file (list of supported RIDs):


The above step is no longer required starting with .NET Core 2.0.

Then, set the desired runtime when you publish your application:

dotnet publish -c Release -r win10-x64
dotnet publish -c Release -r ubuntu.16.10-x64

How to deselect all selected rows in a DataGridView control?

i found out why my first row was default selected and found out how to not select it by default.

By default my datagridview was the object with the first tab-stop on my windows form. Making the tab stop first on another object (maybe disabling tabstop for the datagrid at all will work to) disabled selecting the first row

How do you discover model attributes in Rails?

If you're just interested in the properties and data types from the database, you can use Model.inspect.

irb(main):001:0> User.inspect
=> "User(id: integer, email: string, encrypted_password: string,
 reset_password_token: string, reset_password_sent_at: datetime,
 remember_created_at: datetime, sign_in_count: integer,
 current_sign_in_at: datetime, last_sign_in_at: datetime,
 current_sign_in_ip: string, last_sign_in_ip: string, created_at: datetime,
 updated_at: datetime)"

Alternatively, having run rake db:create and rake db:migrate for your development environment, the file db/schema.rb will contain the authoritative source for your database structure:

ActiveRecord::Schema.define(version: 20130712162401) do
  create_table "users", force: true do |t|
    t.string   "email",                  default: "", null: false
    t.string   "encrypted_password",     default: "", null: false
    t.string   "reset_password_token"
    t.datetime "reset_password_sent_at"
    t.datetime "remember_created_at"
    t.integer  "sign_in_count",          default: 0
    t.datetime "current_sign_in_at"
    t.datetime "last_sign_in_at"
    t.string   "current_sign_in_ip"
    t.string   "last_sign_in_ip"
    t.datetime "created_at"
    t.datetime "updated_at"

How can I get the browser's scrollbar sizes?

If you already have an element with scrollbars on it use:

function getScrollbarHeight(el) {
    return el.getBoundingClientRect().height - el.scrollHeight;

If there is no horzintscrollbar present the function will retun 0

phantomjs not waiting for "full" page load

I found this solution useful in a NodeJS app. I use it just in desperate cases because it launches a timeout in order to wait for the full page load.

The second argument is the callback function which is going to be called once the response is ready.

phantom = require('phantom');

var fullLoad = function(anUrl, callbackDone) {
    phantom.create(function (ph) {
        ph.createPage(function (page) {
  , function (status) {
                if (status !== 'success') {
                    console.error("pahtom: error opening " + anUrl, status);
                } else {
                    // timeOut
                    global.setTimeout(function () {
                        page.evaluate(function () {
                            return document.documentElement.innerHTML;
                        }, function (result) {
                            ph.exit(); // EXTREMLY IMPORTANT
                            callbackDone(result); // callback
                    }, 5000);

var callback = function(htmlBody) {
    // do smth with the htmlBody

fullLoad('your/url/', callback);

How to check if a line is blank using regex

Actually in multiline mode a more correct answer is this:


The accepted answer: ^\s*$ does not match a scenario when the last line is blank (in multiline mode).

How to center icon and text in a android button with width set to "fill parent"

You can create a custom widget:

The Java class IButton:

public class IButton extends RelativeLayout {

private RelativeLayout layout;
private ImageView image;
private TextView text;

public IButton(Context context) {
    this(context, null);

public IButton(Context context, AttributeSet attrs) {
    this(context, attrs, 0);

public IButton(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);

    LayoutInflater inflater = (LayoutInflater) context
    View view = inflater.inflate(R.layout.ibutton, this, true);

    layout = (RelativeLayout) view.findViewById(;

    image = (ImageView) view.findViewById(;
    text = (TextView) view.findViewById(;

    if (attrs != null) {
        TypedArray attributes = context.obtainStyledAttributes(attrs,R.styleable.IButtonStyle);

        Drawable drawable = attributes.getDrawable(R.styleable.IButtonStyle_button_icon);
        if(drawable != null) {

        String str = attributes.getString(R.styleable.IButtonStyle_button_text);



public void setOnClickListener(final OnClickListener l) {

public void setDrawable(int resId) {


The layout ibutton.xml

<RelativeLayout xmlns:android=""
android:clickable="true" >

    android:duplicateParentState="true" />

    android:textColor="#000000" />

In order to use this custom widget:

     ibutton:button_icon="@drawable/ic_action_new" />

You have to provide the namespace for the custom attributes xmlns:ibutton="" where is the root package of the application.

Just put it below xmlns:android="".

The last thing you gonna need are the custom attributes in the attrs.xml.

In the attrs.xml

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

    <declare-styleable name="IButtonStyle">
        <attr name="button_text" />
        <attr name="button_icon" format="integer" />

    <attr name="button_text" />


For better positioning, wrap the custom Button inside a LinearLayout, if you want to avoid potential problems with RelativeLayout positionings.


How to implement static class member functions in *.cpp file?

Yes you can define static member functions in *.cpp file. If you define it in the header, compiler will by default treat it as inline. However, it does not mean separate copies of the static member function will exist in the executable. Please follow this post to learn more about this: Are static member functions in c++ copied in multiple translation units?

Differences between hard real-time, soft real-time, and firm real-time?

Hard Real-Time

The hard real-time definition considers any missed deadline to be a system failure. This scheduling is used extensively in mission critical systems where failure to conform to timing constraints results in a loss of life or property.


  • Air France Flight 447 crashed into the ocean after a sensor malfunction caused a series of system errors. The pilots stalled the aircraft while responding to outdated instrument readings. All 12 crew and 216 passengers were killed.

  • Mars Pathfinder spacecraft was nearly lost when a priority inversion caused system restarts. A higher priority task was not completed on time due to being blocked by a lower priority task. The problem was corrected and the spacecraft landed successfully.

  • An Inkjet printer has a print head with control software for depositing the correct amount of ink onto a specific part of the paper. If a deadline is missed then the print job is ruined.

Firm Real-Time

The firm real-time definition allows for infrequently missed deadlines. In these applications the system can survive task failures so long as they are adequately spaced, however the value of the task's completion drops to zero or becomes impossible.


  • Manufacturing systems with robot assembly lines where missing a deadline results in improperly assembling a part. As long as ruined parts are infrequent enough to be caught by quality control and not too costly, then production continues.

  • A digital cable set-top box decodes time stamps for when frames must appear on the screen. Since the frames are time order sensitive a missed deadline causes jitter, diminishing quality of service. If the missed frame later becomes available it will only cause more jitter to display it, so it's useless. The viewer can still enjoy the program if jitter doesn't occur too often.

Soft Real-Time

The soft real-time definition allows for frequently missed deadlines, and as long as tasks are timely executed their results continue to have value. Completed tasks may have increasing value up to the deadline and decreasing value past it.


  • Weather stations have many sensors for reading temperature, humidity, wind speed, etc. The readings should be taken and transmitted at regular intervals, however the sensors are not synchronized. Even though a sensor reading may be early or late compared with the others it can still be relevant as long as it is close enough.

  • A video game console runs software for a game engine. There are many resources that must be shared between its tasks. At the same time tasks need to be completed according to the schedule for the game to play correctly. As long as tasks are being completely relatively on time the game will be enjoyable, and if not it may only lag a little.

Siewert: Real-Time Embedded Systems and Components.
Liu & Layland: Scheduling Algorithms for Multiprogramming in a Hard Real-Time Environment.
Marchand & Silly-Chetto: Dynamic Scheduling of Soft Aperiodic Tasks and Periodic Tasks with Skips.

What does 'super' do in Python?

Doesn't all of this assume that the base class is a new-style class?

class A:
    def __init__(self):

class B(A):
    def __init__(self):
        super(B, self).__init__()

Will not work in Python 2. class A must be new-style, i.e: class A(object)

Row Offset in SQL Server

I use this technique for pagination. I do not fetch all the rows. For example, if my page needs to display the top 100 rows I fetch only the 100 with where clause. The output of the SQL should have a unique key.

The table has the following:

ID, KeyId, Rank

The same rank will be assigned for more than one KeyId.

SQL is select top 2 * from Table1 where Rank >= @Rank and ID > @Id

For the first time I pass 0 for both. The second time pass 1 & 14. 3rd time pass 2 and 6....

The value of the 10th record Rank & Id is passed to the next

11  21  1
14  22  1
7   11  1
6   19  2
12  31  2
13  18  2

This will have the least stress on the system

Using CSS for a fade-in effect on page load

In response to @A.M.K's question about how to do transitions without jQuery. A very simple example I threw together. If I had time to think this through some more, I might be able to eliminate the JavaScript code altogether:

    body {
        background-color: red;
        transition: background-color 2s ease-in;

    window.onload = function() { = '#00f';


Cluster analysis in R: determine the optimal number of clusters

It's hard to add something too such an elaborate answer. Though I feel we should mention identify here, particularly because @Ben shows a lot of dendrogram examples.

d_dist <- dist(as.matrix(d))   # find distance matrix 
clusters <- identify(hclust(d_dist))

identify lets you interactively choose clusters from an dendrogram and stores your choices to a list. Hit Esc to leave interactive mode and return to R console. Note, that the list contains the indices, not the rownames (as opposed to cutree).

Which Protocols are used for PING?

The usual command line ping tool uses ICMP Echo, but it's true that other protocols can also be used, and they're useful in debugging different kinds of network problems.

I can remember at least arping (for testing ARP requests) and tcping (which tries to establish a TCP connection and immediately closes it, it can be used to check if traffic reaches a certain port on a host) off the top of my head, but I'm sure there are others aswell.

How to make graphics with transparent background in R using ggplot2?

Just to improve YCR's answer:

1) I added black lines on x and y axis. Otherwise they are made transparent too.

2) I added a transparent theme to the legend key. Otherwise, you will get a fill there, which won't be very esthetic.

Finally, note that all those work only with pdf and png formats. jpeg fails to produce transparent graphs.

MyTheme_transparent <- theme(
    panel.background = element_rect(fill = "transparent"), # bg of the panel
    plot.background = element_rect(fill = "transparent", color = NA), # bg of the plot
    panel.grid.major = element_blank(), # get rid of major grid
    panel.grid.minor = element_blank(), # get rid of minor grid
    legend.background = element_rect(fill = "transparent"), # get rid of legend bg = element_rect(fill = "transparent"), # get rid of legend panel bg
    legend.key = element_rect(fill = "transparent", colour = NA), # get rid of key legend fill, and of the surrounding
    axis.line = element_line(colour = "black") # adding a black line for x and y axis

Shadow Effect for a Text in Android?

put these in values/colors.xml

    <color name="light_font">#FBFBFB</color>
    <color name="grey_font">#ff9e9e9e</color>
    <color name="text_shadow">#7F000000</color>
    <color name="text_shadow_white">#FFFFFF</color>

Then in your layout xml here are some example TextView's

Example of Floating text on Light with Dark shadow

<TextView android:id="@+id/txt_example1"
                  android:shadowRadius="2" />

enter image description here

Example of Etched text on Light with Dark shadow

<TextView android:id="@+id/txt_example2"
                android:shadowRadius="1" />

enter image description here

Example of Crisp text on Light with Dark shadow

<TextView android:id="@+id/txt_example3"
                android:shadowRadius="1" />

enter image description here

Notice the positive and negative values... I suggest to play around with the colors/values yourself but ultimately you can adjust these settings to get the effect your looking for.

Get value from hashmap based on key to JSTL

I had issue with the solutions mentioned above as specifying the string key would give me javax.el.PropertyNotFoundException. The code shown below worked for me. In this I used status to count the index of for each loop and displayed the value of index I am interested on

<c:forEach items="${requestScope.key}"  var="map" varStatus="status" >
    <c:if test="${status.index eq 1}">
        <option><c:out value=${map.value}/></option>

How to convert string date to Timestamp in java?

All you need to do is change the string within the java.text.SimpleDateFormat constructor to: "MM-dd-yyyy HH:mm:ss".

Just use the appropriate letters to build the above string to match your input date.

jQuery DatePicker with today as maxDate

$(".datepicker").datepicker({maxDate: '0'});

This will set the maxDate to +0 days from the current date (i.e. today). See:

split string only on first instance - java

String[] func(String apple){
String[] tmp = new String[2];
for(int i=0;i<apple.length;i++){
return tmp;
//returns string_ARRAY_!

i like writing own methods :)

Is there a Python equivalent to Ruby's string interpolation?

String interpolation is going to be included with Python 3.6 as specified in PEP 498. You will be able to do this:

name = 'Spongebob Squarepants'
print(f'Who lives in a Pineapple under the sea? \n{name}')

Note that I hate Spongebob, so writing this was slightly painful. :)

Appending an element to the end of a list in Scala

We can append or prepend two lists or list&array

var l = List(1,2,3)    
l = l :+ 4 
Result : 1 2 3 4  
var ar = Array(4, 5, 6)    
for(x <- ar)    
{ l = l :+ x }  

Result:1 2 3 4 5 6


var l = List[Int]()  
   for(x <- ar)  
    { l= x :: l } //prepending    

Result:6 5 4 1 2 3

Subprocess changing directory

Another option based on this answer:

This allows you to execute multiple commands (e.g cd) in the same process.

import subprocess

commands = '''
cd some-directory
cd another-directory

process = subprocess.Popen('/bin/bash', stdin=subprocess.PIPE, stdout=subprocess.PIPE)
out, err = process.communicate(commands.encode('utf-8'))

Is there any way to kill a Thread?

You can execute your command in a process and then kill it using the process id. I needed to sync between two thread one of which doesn’t return by itself.

processIds = []

def executeRecord(command):

    process = subprocess.Popen(command, stdout=subprocess.PIPE)

    #Command that doesn't return by itself"utf-8")

def recordThread(command, timeOut):

    thread = Thread(target=executeRecord, args=(command,))

    os.kill(processIds.pop(), signal.SIGINT)


Finding longest string in array

With ES6 supported also duplicate string

var allLongestStrings = arrayOfStrings => {
  let maxLng = Math.max( elem => elem.length))
  return arrayOfStrings.filter(elem => elem.length === maxLng)

let arrayOfStrings = ["aba", "aa", "ad", "vcd","aba"]


Setting default values for columns in JPA

@Column(columnDefinition="tinyint(1) default 1")

I just tested the issue. It works just fine. Thanks for the hint.

About the comments:

private double price = 0.0;

This one doesn't set the default column value in the database (of course).

How do I configure HikariCP in my Spring Boot app in my files?

According to the documentation it is changed,

Example :

        url: 'jdbc:mysql://localhost/db?useSSL=false'
        username: root
        password: pass
        driver: com.mysql.jdbc.Driver
            minIdle: 10
            idle-timeout: 10000
            maximumPoolSize: 30

These are the following configuration changes we can do on hikari, please add/update according to your need.


Change the URL in the browser without loading the new page using JavaScript

Browser security settings prevent people from modifying the displayed url directly. You could imagine the phishing vulnerabilities that would cause.

Only reliable way to change the url without changing pages is to use an internal link or hash. e.g.: becomes . This technique is often used in hijax(AJAX + preserve history).

When doing this I'll often just use links for the actions with the hash as the href, then add click events with jquery that use the requested hash to determine and delegate the action.

I hope that sets you on the right path.

Should I use 'has_key()' or 'in' on Python dicts?

Solution to dict.has_key() is deprecated, use 'in' -- sublime text editor 3

Here I have taken an example of dictionary named 'ages' -

ages = {}

# Add a couple of names to the dictionary
ages['Sue'] = 23

ages['Peter'] = 19

ages['Andrew'] = 78

ages['Karren'] = 45

# use of 'in' in if condition instead of function_name.has_key(key-name).
if 'Sue' in ages:

    print "Sue is in the dictionary. She is", ages['Sue'], "years old"


    print "Sue is not in the dictionary"

How to convert Base64 String to javascript file object like as from file input form?

Way 1: only works for dataURL, not for other types of url.

 function dataURLtoFile(dataurl, filename) {_x000D_
        var arr = dataurl.split(','),_x000D_
            mime = arr[0].match(/:(.*?);/)[1],_x000D_
            bstr = atob(arr[1]), _x000D_
            n = bstr.length, _x000D_
            u8arr = new Uint8Array(n);_x000D_
            u8arr[n] = bstr.charCodeAt(n);_x000D_
        return new File([u8arr], filename, {type:mime});_x000D_
    //Usage example:_x000D_
    var file = dataURLtoFile('data:text/plain;base64,aGVsbG8gd29ybGQ=','hello.txt');_x000D_

Way 2: works for any type of url, (http url, dataURL, blobURL, etc...)

 //return a promise that resolves with a File instance_x000D_
    function urltoFile(url, filename, mimeType){_x000D_
        return (fetch(url)_x000D_
            .then(function(res){return res.arrayBuffer();})_x000D_
            .then(function(buf){return new File([buf], filename,{type:mimeType});})_x000D_
    //Usage example:_x000D_
    urltoFile('data:text/plain;base64,aGVsbG8gd29ybGQ=', 'hello.txt','text/plain')_x000D_
    .then(function(file){ console.log(file);});

Where is the kibana error log? Is there a kibana error log?

In kibana 4.0.2 there is no --log-file option. If I start kibana as a service with systemctl start kibana I find log in /var/log/messages

Excel VBA If cell.Value =... then

You can determine if as certain word is found in a cell by using

If InStr(cell.Value, "Word1") > 0 Then

If Word1 is found in the string the InStr() function will return the location of the first character of Word1 in the string.

Using PHP with

I was looking for a really simple way to get PHP to send a message to clients.

This doesn't require any additional PHP libraries - it just uses sockets.

Instead of trying to connect to the websocket interface like so many other solutions, just connect to the node.js server and use .on('data') to receive the message.

Then, can forward it along to clients.

Detect a connection from your PHP server in Node.js like this:

//You might have something like this - just included to show object setup
var app = express();
var server = http.createServer(app);
var io = require('').listen(server);

server.on("connection", function(s) {
    //If connection is from our server (localhost)
    if(s.remoteAddress == "::ffff:") {
        s.on('data', function(buf) {
            var js = JSON.parse(buf);
            io.emit(js.msg,; //Send the msg to clients

Here's the incredibly simple php code - I wrapped it in a function - you may come up with something better.

Note that 8080 is the port to my Node.js server - you may want to change.

function sio_message($message, $data) {
    $socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
    $result = socket_connect($socket, '', 8080);
    if(!$result) {
        die('cannot connect '.socket_strerror(socket_last_error()).PHP_EOL);
    $bytes = socket_write($socket, json_encode(Array("msg" => $message, "data" => $data)));

You can use it like this:

sio_message("chat message","Hello from PHP!");

You can also send arrays which are converted to json and passed along to clients.

sio_message("DataUpdate",Array("Data1" => "something", "Data2" => "something else"));

This is a useful way to "trust" that your clients are getting legitimate messages from the server.

You can also have PHP pass along database updates without having hundreds of clients query the database.

I wish I'd found this sooner - hope this helps!

Description Box using "onmouseover"

This an old question but for people still looking. In JS you can now use the title property.

button.title = ("Popup text here");

Python wildcard search in string

Easy method is try os.system:

import os
text = 'this is text'
os.system("echo %s | grep 't*'" % text)

How to print a percentage value in python?

Just for the sake of completeness, since I noticed no one suggested this simple approach:

>>> print("%.0f%%" % (100 * 1.0/3))


  • %.0f stands for "print a float with 0 decimal places", so %.2f would print 33.33
  • %% prints a literal %. A bit cleaner than your original +'%'
  • 1.0 instead of 1 takes care of coercing the division to float, so no more 0.0

multiple conditions for JavaScript .includes() method

How about ['hello', 'hi', 'howdy'].includes(str)?

Printing a java map Map<String, Object> - How?

There is a get method in HashMap:

for (String keys : objectSet.keySet())  
   System.out.println(keys + ":"+ objectSet.get(keys));

Cross-Domain Cookies

Do what Google is doing. Create a PHP file that sets the cookie on all 3 domains. Then on the domain where the theme is going to set, create a HTML file that would load the PHP file that sets cookie on the other 2 domains. Example:

      <p>Please wait.....</p>
      <img src="" />
      <img src="" />

Then add an onload callback on body tag. The document will only load when the images completely load that is when cookies are set on the other 2 domains. Onload Callback :

   function loadComplete(){
      window.location="";//URL of domain1
<body onload="loadComplete()">


We set the cookies on the other domains using a PHP file like this :

   setcookie("theme", $_GET['theme'], time()+3600);

Now cookies are set on the three domains.

How can I dynamically set the position of view in Android?

I would recommend using setTranslationX and setTranslationY. I'm only just getting started on this myself, but these seem to be the safest and preferred way of moving a view. I guess it depends a lot on what exactly you're trying to do, but this is working well for me for 2D animation.

Assert equals between 2 Lists in Junit

I don't this the all the above answers are giving the exact solution for comparing two lists of Objects. Most of above approaches can be helpful in following limit of comparisons only - Size comparison - Reference comparison

But if we have same sized lists of objects and different data on the objects level then this comparison approaches won't help.

I think the following approach will work perfectly with overriding equals and hashcode method on the user-defined object.

I used Xstream lib for override equals and hashcode but we can override equals and hashcode by out won logics/comparison too.

Here is the example for your reference

    import com.thoughtworks.xstream.XStream;

    import java.text.ParseException;
    import java.util.ArrayList;
    import java.util.List;

    class TestClass {
      private String name;
      private String id;

      public void setName(String value) { = value;

      public String getName() {

      public String getId() {
        return id;

      public void setId(String id) { = id;

       * @see java.lang.Object#equals(java.lang.Object)
      public boolean equals(Object o) {
        XStream xstream = new XStream();
        String oxml = xstream.toXML(o);
        String myxml = xstream.toXML(this);

        return myxml.equals(oxml);

       * @see java.lang.Object#hashCode()
      public int hashCode() {
        XStream xstream = new XStream();
        String myxml = xstream.toXML(this);
        return myxml.hashCode();

    public class XstreamCompareTest {
      public static void main(String[] args) throws ParseException {

      private static void checkObjectEquals() {
        List<TestClass> testList1 = new ArrayList<TestClass>();
        TestClass tObj1 = new TestClass();

        TestClass tObj2 = new TestClass();

        testList1.sort((TestClass t1, TestClass t2) -> t1.getId().compareTo(t2.getId()));

        List<TestClass> testList2 = new ArrayList<TestClass>();
        TestClass tObj3 = new TestClass();

        TestClass tObj4 = new TestClass();

        testList2.sort((TestClass t1, TestClass t2) -> t1.getId().compareTo(t2.getId()));

        if (isNotMatch(testList1, testList2)) {
          System.out.println("The list are not matched");
        } else {
          System.out.println("The list are matched");


      private static boolean isNotMatch(List<TestClass> clist1, List<TestClass> clist2) {
        return clist1.size() != clist2.size() || !clist1.equals(clist2);

The most important thing is that you can ignore the fields by Annotation (@XStreamOmitField) if you don't want to include any fields on the equal check of Objects. There are many Annotations like this to configure so have a look deep about the annotations of this lib.

I am sure this answer will save your time to identify the correct approach for comparing two lists of objects :). Please comment if you see any issues on this.

How do I list the symbols in a .so file

If your .so file is in elf format, you can use readelf program to extract symbol information from the binary. This command will give you the symbol table:

readelf -Ws /usr/lib/

You only should extract those that are defined in this .so file, not in the libraries referenced by it. Seventh column should contain a number in this case. You can extract it by using a simple regex:

readelf -Ws /usr/lib/ | grep '^\([[:space:]]\+[^[:space:]]\+\)\{6\}[[:space:]]\+[[:digit:]]\+'

or, as proposed by Caspin,:

readelf -Ws /usr/lib/ | awk '{print $8}';

Transparent ARGB hex value

Transparency is controlled by the alpha channel (AA in #AARRGGBB). Maximal value (255 dec, FF hex) means fully opaque. Minimum value (0 dec, 00 hex) means fully transparent. Values in between are semi-transparent, i.e. the color is mixed with the background color.

To get a fully transparent color set the alpha to zero. RR, GG and BB are irrelevant in this case because no color will be visible. This means #00FFFFFF ("transparent White") is the same color as #00F0F8FF ("transparent AliceBlue"). To keep it simple one chooses black (#00000000) or white (#00FFFFFF) if the color does not matter.

In the table you linked to you'll find Transparent defined as #00FFFFFF.

Remove empty strings from a list of strings

As reported by Aziz Alto filter(None, lstr) does not remove empty strings with a space ' ' but if you are sure lstr contains only string you can use filter(str.strip, lstr)

>>> lstr = ['hello', '', ' ', 'world', ' ']
>>> lstr
['hello', '', ' ', 'world', ' ']
>>> ' '.join(lstr).split()
['hello', 'world']
>>> filter(str.strip, lstr)
['hello', 'world']

Compare time on my pc

>>> from timeit import timeit
>>> timeit('" ".join(lstr).split()', "lstr=['hello', '', ' ', 'world', ' ']", number=10000000)
>>> timeit('filter(str.strip, lstr)', "lstr=['hello', '', ' ', 'world', ' ']", number=10000000)

The fastest solution to remove '' and empty strings with a space ' ' remains ' '.join(lstr).split().

As reported in a comment the situation is different if your strings contain spaces.

>>> lstr = ['hello', '', ' ', 'world', '    ', 'see you']
>>> lstr
['hello', '', ' ', 'world', '    ', 'see you']
>>> ' '.join(lstr).split()
['hello', 'world', 'see', 'you']
>>> filter(str.strip, lstr)
['hello', 'world', 'see you']

You can see that filter(str.strip, lstr) preserve strings with spaces on it but ' '.join(lstr).split() will split this strings.

Powershell remoting with ip-address as target

On your machine* run 'Set-Item WSMan:\localhost\Client\TrustedHosts -Value "$ipaddress"

*Machine from where you are running PSSession

How to find sum of multiple columns in a table in SQL Server 2005?

Just as a regular SELECT?

   Val1, Val2, Val3,
   Total = Val1 + Val2 + Val3
FROM dbo.Emp

Or do you want to determine that total and update the table with those values?

UPDATE dbo.Emp
SET Total = Val1 + Val2 + Val3

If you want to have this total be current at all times - you should have a computed column in your table:

ADD CurrentTotal AS Val1 + Val2 + Val3 PERSISTED

Then you will always get the current total - even if the values change:

   Val1, Val2, Val3, CurrentTotal
FROM dbo.Emp

What is the difference between Java RMI and RPC?

RPC is an old protocol based on C.It can invoke a remote procedure and make it look like a local call.RPC handles the complexities of passing that remote invocation to the server and getting the result to client.

Java RMI also achieves the same thing but slightly differently.It uses references to remote objects.So, what it does is that it sends a reference to the remote object alongwith the name of the method to invoke.It is better because it results in cleaner code in case of large programs and also distribution of objects over the network enables multiple clients to invoke methods in the server instead of establishing each connection individually.

How to remove an element from the flow?

position: fixed; will also "pop" an element out of the flow, as you say. :)

position: absolute must be accompanied by a position. e.g. top: 1rem; left: 1rem

position: fixed however, will place the element where it would normally appear according to the document flow, but prevent it from moving after that. It also effectively set's the height to 0px (with regards to the dom) so that the next element shifts up over it.

This can be pretty cool, because you can set position: fixed; z-index: 1 (or whatever z-index you need) so that it "pops" over the next element.

This is especially useful for fixed position headers that stay at the top when you scroll, for example.

How do I make a batch file terminate upon encountering an error?

Check the errorlevel in an if statement, and then exit /b (exit the batch file only, not the entire cmd.exe process) for values other than 0.

same-executable-over-and-over.exe /with different "parameters"
if %errorlevel% neq 0 exit /b %errorlevel%

If you want the value of the errorlevel to propagate outside of your batch file

if %errorlevel% neq 0 exit /b %errorlevel%

but if this is inside a for it gets a bit tricky. You'll need something more like:

setlocal enabledelayedexpansion
for %%f in (C:\Windows\*) do (
    same-executable-over-and-over.exe /with different "parameters"
    if !errorlevel! neq 0 exit /b !errorlevel!

Edit: You have to check the error after each command. There's no global "on error goto" type of construct in cmd.exe/ batch. I've also updated my code per CodeMonkey, although I've never encountered a negative errorlevel in any of my batch-hacking on XP or Vista.

Overlapping Views in Android

The simples way arround is to put -40dp margin at the buttom of the top imageview

how to check if string contains '+' character

[+]is simpler

    String s = "ddjdjdj+kfkfkf";

    if(s.contains ("+"))
        String parts[] = s.split("[+]");
        s =  parts[0]; // i want to strip part after  +

How to remove duplicates from Python list and keep order?

If your input is already sorted, then there may be a simpler way to do it:

from operator import itemgetter
from itertools import groupby
unique_list = list(map(itemgetter(0), groupby(yourList)))

PG::ConnectionBad - could not connect to server: Connection refused

I had to reinstall my postgres, great instructions outlined here:

Then I had to create postgres user: /usr/local/opt/postgres/bin/createuser -s postgres

This approach will clobber all of your local data so please back up your data if needed.

No more data to read from socket error

Downgrading the JRE from 7 to 6 fixed this issue for me.

jquery: get value of custom attribute

You need some form of iteration here, as val (except when called with a function) only works on the first element:


should be:

$("input[placeholder]").each( function () {
    $(this).val( $(this).attr("placeholder") );


$("input[placeholder]").val(function() {
    return $(this).attr("placeholder");

ImportError in importing from sklearn: cannot import name check_build

I had problems importing SKLEARN after installing a new 64bit version of Python 3.4 from

Turns out that it was the SCIPY module that was broken, and alos failed when I tried to "import scipy".

Solution was to uninstall scipy and reinstall it with pip3:

C:\> pip uninstall scipy

[lots of reporting messages deleted]

Proceed (y/n)? y
  Successfully uninstalled scipy-1.0.0

C:\Users\>pip3 install scipy

Collecting scipy
  Downloading scipy-1.0.0-cp36-none-win_amd64.whl (30.8MB)
    100% |¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦| 30.8MB 33kB/s
Requirement already satisfied: numpy>=1.8.2 in c:\users\johnmccurdy\appdata\loca
l\programs\python\python36\lib\site-packages (from scipy)
Installing collected packages: scipy
Successfully installed scipy-1.0.0

Python 3.6.4 (v3.6.4:d48eceb, Dec 19 2017, 06:54:40) [MSC v.1900 64 bit (AMD64)]
 on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import scipy
>>> import sklearn

org.hibernate.hql.internal.ast.QuerySyntaxException: table is not mapped

It means your table is not mapped to the JPA. Either Name of the table is wrong (Maybe case sensitive), or you need to put an entry in the XML file.

Happy Coding :)

Java FileWriter how to write to next Line

.newLine() is the best if your system property line.separator is proper . and sometime you don't want to change the property runtime . So alternative solution is appending \n

How can I get column names from a table in SQL Server?

You can write this query to get column name and all details without using INFORMATION_SCHEMA in MySql :

SHOW COLUMNS FROM database_Name.table_name;

Append to the end of a file in C

Open with append:

pFile2 = fopen("myfile2.txt", "a");

then just write to pFile2, no need to fseek().

How to extract a value from a string using regex and a shell?

you can use the shell(bash for example)

$ string="12 BBQ ,45 rofl, 89 lol"
$ echo ${string% rofl*}
12 BBQ ,45
$ string=${string% rofl*}
$ echo ${string##*,}

Import and Export Excel - What is the best library?

the new version of ExcelPackage is here

I'm still fighting with the export to excel function since my application should export some data to excel-template 2007

this project seems fine to me, and the developer is very responsive to bugs and issues.

how to make a specific text on TextView BOLD

I used this code to bold specific words...

    Spanned string = Html.fromHtml("Normal string <b>BOLD STRING</b>");

How do you set autocommit in an SQL Server session?

I wanted a more permanent and quicker way. Because I tend to forget to add extra lines before writing my actual Update/Insert queries.

I did it by checking SET IMPLICIT_TRANSACTIONS check-box from Options. To navigate to Options Select Tools>Options>Query Execution>SQL Server>ANSI in your Microsoft SQL Server Management Studio.

Just make sure to execute commit or rollback after you are done executing your queries. Otherwise, the table you would have run the query will be locked for others.

Clicking at coordinates without identifying element

    WebElement button = driver.findElement(By.xpath("//button[@type='submit']"));
    int height = button.getSize().getHeight();
    int width = button.getSize().getWidth();
    Actions act = new Actions(driver);

LaTex left arrow over letter in math mode

Use \overleftarrow to create a long arrow to the left.


LaTeX output

Show "Open File" Dialog

Addition to what Albert has already said:

This code (a mashup of various samples) provides the ability to have a SaveAs dialog box

Function getFileName() As String
    Dim fDialog    As Object
    Set fDialog = Application.FileDialog(msoFileDialogSaveAs)
    Dim varFile As Variant

    With fDialog
       .AllowMultiSelect = False
       .Title = "Select File Location to Export XLSx :"
       .InitialFileName = "jeffatwood.xlsx"

    If .Show = True Then
       For Each varFile In .SelectedItems
         getFileName = varFile
    End If
End With
End Function

Typescript - multidimensional array initialization

Beware of the use of push method, if you don't use indexes, it won't work!

var main2dArray: Things[][] = []


gives only a 1 line array!


main2dArray[0] = someTmp1dArray
main2dArray[1] = someOtherTmp1dArray

to get your 2d array working!!!

Other beware! foreach doesn't seem to work with 2d arrays!

JSONException: Value of type java.lang.String cannot be converted to JSONObject

For me, I just needed to use getString() vs. getJSONObject() (the latter threw that error):

JSONObject jsonObject = new JSONObject(jsonString);
String valueIWanted = jsonObject.getString("access_token"))

TypeError: Object of type 'bytes' is not JSON serializable

I guess the answer you need is referenced here Python sets are not json serializable

Not all datatypes can be json serialized . I guess pickle module will serve your purpose.

Node.js version on the command line? (not the REPL)

open node.js command prompt
run this command

node -v

Chrome Extension: Make it run every page load

You can put your script into a content-script, see

How to format a DateTime in PowerShell

The question is answered, but there is some more information missing:

Variable vs. Cmdlet

You have a value in the $Date variable and the -f operator does work in this form: 'format string' -f values. If you call Get-Date -format "yyyyMMdd" you call a cmdlet with some parameters. The value "yyyyMMdd" is the value for parameter Format (try help Get-Date -param Format).

-f operator

There are plenty of format strings. Look at least at part1 and part2. She uses string.Format('format string', values'). Think of it as 'format-string' -f values, because the -f operator works very similarly as string.Format method (although there are some differences (for more information look at question at Stack Overflow: How exactly does the RHS of PowerShell's -f operator work?).

How to split string and push in array using jquery

You don't need jQuery for that, you can do it with normal javascript:

var str = "a,b,c,d";
var res = str.split(","); // this returns an array

Difference between timestamps with/without time zone in PostgreSQL

Here is an example that should help. If you have a timestamp with a timezone, you can convert that timestamp into any other timezone. If you haven't got a base timezone it won't be converted correctly.

SELECT now(),
   now() AT TIME ZONE 'CST',
   now()::timestamp AT TIME ZONE 'CST'


-[ RECORD 1 ]---------------------------
now      | 2018-09-15 17:01:36.399357+03
now      | 2018-09-15 17:01:36.399357
timezone | 2018-09-15 08:01:36.399357
timezone | 2018-09-16 02:01:36.399357+03

Calculating Time Difference

The datetime module will do all the work for you:

>>> import datetime
>>> a =
>>> # ...wait a while...
>>> b =
>>> print(b-a)

If you don't want to display the microseconds, just use (as gnibbler suggested):

>>> a =
>>> b =
>>> print(b-a)

How to display multiple images in one figure correctly?

You could try the following:

import matplotlib.pyplot as plt
import numpy as np

def plot_figures(figures, nrows = 1, ncols=1):
    """Plot a dictionary of figures.

    figures : <title, figure> dictionary
    ncols : number of columns of subplots wanted in the display
    nrows : number of rows of subplots wanted in the figure

    fig, axeslist = plt.subplots(ncols=ncols, nrows=nrows)
    for ind,title in zip(range(len(figures)), figures):
        axeslist.ravel()[ind].imshow(figures[title], cmap=plt.jet())
    plt.tight_layout() # optional

# generation of a dictionary of (title, images)
number_of_im = 20
figures = {'im'+str(i): np.random.randint(10, size=(h,w)) for i in range(number_of_im)}

# plot of the images in a figure, with 5 rows and 4 columns
plot_figures(figures, 5, 4)

However, this is basically just copy and paste from here: Multiple figures in a single window for which reason this post should be considered to be a duplicate.

I hope this helps.

Getting "Skipping JaCoCo execution due to missing execution data file" upon executing JaCoCo

Try to use:

mvn jacoco:report -debug

to see the details about your reporting process.

I configured my jacoco like this:


Then mvn jacoco:report -debug shows it using the default configuration, which means jacoco.exec is not in ~/jacoco.exec. The error says missing execution data file.

So just use the default configuration:


And everything works fine.

How to force Chrome's script debugger to reload javascript?

There are also 2 (quick) workarounds:

  1. Use incognito mode wile debugging, close the window and reopen it.
  2. Delete your browsing history

How to get index in Handlebars each helper?

This has changed in the newer versions of Ember.

For arrays:

{{#each array}}
    {{_view.contentIndex}}: {{this}}

It looks like the #each block no longer works on objects. My suggestion is to roll your own helper function for it.

Thanks for this tip.

Intellij Idea: Importing Gradle project - getting JAVA_HOME not defined yet

For MacOS this worked for me without the need to hardcode a particular Java version:

launchctl setenv JAVA_HOME "$(jenv javahome)"

How to connect to Mysql Server inside VirtualBox Vagrant?

Log in to your box with ssh [email protected] -p 2222 (password vagrant)

Then: sudo nano /etc/mysql/my.cnf and comment out the following lines with #


save it & exit

then: sudo service mysql restart

Then you can connect through SSH to your MySQL server.

ASP.NET Identity reset password

Or how can I reset without knowing the current one (user forgot password)?

If you want to change a password using the UserManager but you do not want to supply the user's current password, you can generate a password reset token and then use it immediately instead.

string resetToken = await UserManager.GeneratePasswordResetTokenAsync(model.Id);
IdentityResult passwordChangeResult = await UserManager.ResetPasswordAsync(model.Id, resetToken, model.NewPassword);

Can I change a column from NOT NULL to NULL without dropping it?


where {DataType} is the current data type of that column (For example int or varchar(10))

Remove the last character from a string

First, I try without a space, rtrim($arraynama, ","); and get an error result.

Then I add a space and get a good result:

$newarraynama = rtrim($arraynama, ", ");

How to get Wikipedia content using Wikipedia's API?

See this section on the MediaWiki docs

These are the key parameters.


rvsection = 0 specifies to only return the lead section.

See this example.

To get the HTML, you can use similarly use action=parse

Note, that you'll have to strip out any templates or infoboxes.

Viewing contents of a .jar file

I prefer JAR Browser, it has a simple interface where you can browse multiple JARs, and search for a specific class across multiple JARs simultaneously.

Tomcat is not running even though JAVA_HOME path is correct

I had Win 8 x86 installed. My Path variable had entry C:\Program Files\Java\jdk1.6.0_31\bin and I also had following variables:

  • JAVA_HOME : C:\Program Files\Java\jdk1.6.0_31;
  • JRE_HOME : C:\Program Files\Java\jre6;

My tomcat is installed at C:\Program Files\Apache Software Foundation\apache-tomcat-7.0.41

And still it did not worked for me.

I tried by replacing Program Files in those paths with Progra~1. I also tried by moving JAVA to another folder so that full path to it does not contain any spaces. But nothing worked.

Finally environment variables that worked for me are:

  • Kept path variable as is with full Program Files i.e. C:\Program Files\Java\jdk1.6.0_31\bin
  • JAVA_HOME : C:\Program Files\Java\jdk1.6.0_31
  • Deleted JRE_HOME

So what I did is removed JRE_HOME and removed semicolon at the end of JAVA_HOME. I think semicolon should not be an issue, though I removed it. I am giving these settings, since after a lot of googling nothing worked for me and suddenly these seem to work. You can replicate and see if it works for you.

This also worked for Win 7 x64, where

  • Path variable contained C:\Program Files (x86)\Java\jdk1.7.0_17\bin
  • JAVA_HOME is set to C:\Program Files (x86)\Java\jdk1.7.0_17 (without semicoln)

Please tell me why this worked, I know removing JRE_HOME was weird solution, but any guesses what difference it makes?

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

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

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


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

How do I add a auto_increment primary key in SQL Server database?

You can also perform this action via SQL Server Management Studio.

Right click on your selected table -> Modify

Right click on the field you want to set as PK --> Set Primary Key

Under Column Properties set "Identity Specification" to Yes, then specify the starting value and increment value.

Then in the future if you want to be able to just script this kind of thing out you can right click on the table you just modified and select


so that you can see for yourself the correct syntax to perform this action.

How do I navigate to a parent route from a child route?

This seems to work for me as of Spring 2017:

goBack(): void {
  this.router.navigate(['../'], { relativeTo: this.route });

Where your component ctor accepts ActivatedRoute and Router, imported as follows:

import { ActivatedRoute, Router } from '@angular/router';

Where does linux store my syslog?

In addition to the accepted answer, it is useful to know the following ...

Each of those functions should have manual pages associated with them.

If you run man -k syslog (a keyword search of man pages) you will get a list of man pages that refer to, or are about syslog

$ man -k syslog
logger (1)           - a shell command interface to the syslog(3) system l...
rsyslog.conf (5)     - rsyslogd(8) configuration file
rsyslogd (8)         - reliable and extended syslogd
syslog (2)           - read and/or clear kernel message ring buffer; set c...
syslog (3)           - send messages to the system logger
vsyslog (3)          - send messages to the system logger

You need to understand the manual sections in order to delve further.

Here's an excerpt from the man page for man, that explains man page sections :

The table below shows the section numbers of the manual followed  by
the types of pages they contain.

   1   Executable programs or shell commands
   2   System calls (functions provided by the kernel)
   3   Library calls (functions within program libraries)
   4   Special files (usually found in /dev)
   5   File formats and conventions eg /etc/passwd
   6   Games
   7   Miscellaneous  (including  macro  packages and conven-
       tions), e.g. man(7), groff(7)
   8   System administration commands (usually only for root)
   9   Kernel routines [Non standard]

To read the above run

$man man 

So, if you run man 3 syslog you get a full manual page for the syslog function that you called in your code.

SYSLOG(3)                Linux Programmer's Manual                SYSLOG(3)

   closelog,  openlog,  syslog,  vsyslog  - send messages to the system

   #include <syslog.h>

   void openlog(const char *ident, int option, int facility);
   void syslog(int priority, const char *format, ...);
   void closelog(void);

   #include <stdarg.h>

   void vsyslog(int priority, const char *format, va_list ap);

Not a direct answer but hopefully you will find this useful.

React proptype array with shape

If I am to define the same proptypes for a particular shape multiple times, I like abstract it out to a proptypes file so that if the shape of the object changes, I only have to change the code in one place. It helps dry up the codebase a bit.


// Inside my proptypes.js file
import PT from 'prop-types';

export const product = {
  id: PT.number.isRequired,
  title: PT.string.isRequired,
  sku: PT.string.isRequired,
  description: PT.string.isRequired,

// Inside my component file
import PT from 'prop-types';
import { product } from './proptypes;

List.propTypes = {
  productList: PT.arrayOf(product)

curl error 18 - transfer closed with outstanding read data remaining

I've solved this error by this way.

$ch = curl_init ();
curl_setopt ( $ch, CURLOPT_URL, 'http://www.someurl/' );
curl_setopt ( $ch, CURLOPT_TIMEOUT, 30);
$response = curl_exec ( $ch );
$data = ob_get_clean();
if(curl_getinfo($ch, CURLINFO_HTTP_CODE) == 200 ) success;

Error still occurs, but I can handle response data in variable.

Dynamically add item to jQuery Select2 control that uses AJAX

Extending on Bumptious Q Bangwhistle's answer:

$('#select2').append($('<option>', { 
    value: item,
    text : item 

This would add the new options into the <select> tags and lets select2 re-render it.

How to check for a valid Base64 encoded string

public static bool IsBase64String1(string value)
            if (string.IsNullOrEmpty(value))
                return false;
                if (value.EndsWith("="))
                    value = value.Trim();
                    int mod4 = value.Length % 4;
                    if (mod4 != 0)
                        return false;
                    return true;

                    return false;
            catch (FormatException)
                return false;

When to use in vs ref vs out

You need to use ref if you plan to read and write to the parameter. You need to use out if you only plan to write. In effect, out is for when you'd need more than one return value, or when you don't want to use the normal return mechanism for output (but this should be rare).

There are language mechanics that assist these use cases. Ref parameters must have been initialized before they are passed to a method (putting emphasis on the fact that they are read-write), and out parameters cannot be read before they are assigned a value, and are guaranteed to have been written to at the end of the method (putting emphasis on the fact that they are write only). Contravening to these principles results in a compile-time error.

int x;
Foo(ref x); // error: x is uninitialized

void Bar(out int x) {}  // error: x was not written to

For instance, int.TryParse returns a bool and accepts an out int parameter:

int value;
if (int.TryParse(numericString, out value))
    /* numericString was parsed into value, now do stuff */
    /* numericString couldn't be parsed */

This is a clear example of a situation where you need to output two values: the numeric result and whether the conversion was successful or not. The authors of the CLR decided to opt for out here since they don't care about what the int could have been before.

For ref, you can look at Interlocked.Increment:

int x = 4;
Interlocked.Increment(ref x);

Interlocked.Increment atomically increments the value of x. Since you need to read x to increment it, this is a situation where ref is more appropriate. You totally care about what x was before it was passed to Increment.

In the next version of C#, it will even be possible to declare variable in out parameters, adding even more emphasis on their output-only nature:

if (int.TryParse(numericString, out int value))
    // 'value' exists and was declared in the `if` statement
    // conversion didn't work, 'value' doesn't exist here

Foreign key referring to primary keys across multiple tables?

I know this is long stagnant topic, but in case anyone searches here is how I deal with multi table foreign keys. With this technique you do not have any DBA enforced cascade operations, so please make sure you deal with DELETE and such in your code.

Table 1 Fruit
pk_fruitid, name
1, apple
2, pear

Table 2 Meat
Pk_meatid, name
1, beef
2, chicken

Table 3 Entity's
PK_entityid, anme
1, fruit
2, meat
3, desert

Table 4 Basket (Table using fk_s)
PK_basketid, fk_entityid, pseudo_entityrow
1, 2, 2 (Chicken - entity denotes meat table, pseudokey denotes row in indictaed table)
2, 1, 1 (Apple)
3, 1, 2 (pear)
4, 3, 1 (cheesecake)

SO Op's Example would look like this

type    id      name
1      khce1   gold
2      khsn1   silver

1 employees_ce
2 employees_sn

Most efficient way to concatenate strings?

The most efficient is to use StringBuilder, like so:

StringBuilder sb = new StringBuilder();
String strResult = sb.ToString();

@jonezy: String.Concat is fine if you have a couple of small things. But if you're concatenating megabytes of data, your program will likely tank.

How to resolve the C:\fakepath?

I use the object FileReader on the input onchange event for your input file type! This example uses the readAsDataURL function and for that reason you should have an tag. The FileReader object also has readAsBinaryString to get the binary data, which can later be used to create the same file on your server


var input = document.getElementById("inputFile");
var fReader = new FileReader();
fReader.onloadend = function(event){
    var img = document.getElementById("yourImgTag");
    img.src =;

Why doesn't height: 100% work to expand divs to the screen height?

Try to play around also with the calc and overflow functions

.myClassName {
    overflow: auto;
    height: calc(100% - 1.5em);

Convert List to Pandas Dataframe Column

You can directly call the


method and pass your list as parameter.

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


0            Thanks You
1   Its fine no problem
2          Are you sure

And if you have multiple lists and you want to make a dataframe out of it.You can do it as following:

import pandas as pd
names =["A","B","C","D"]
salary =[50000,90000,41000,62000]
age = [24,24,23,25]
data = pd.DataFrame([names,salary,age]) #Each list would be added as a row
data = data.transpose() #To Transpose and make each rows as columns
data.columns=['Names','Salary','Age'] #Rename the columns


    Names   Salary  Age
0       A    50000   24
1       B    90000   24
2       C    41000   23
3       D    62000   25

Android Studio - Device is connected but 'offline'

In my case (same problem - that Nexus 5 is connected but with "offline" status) the problem was solved by "Invalidate caches and Restart" in Android Studio. Suppose that problem was in adb and restarting Android Studio causes to adb restart.

Permission denied (publickey,keyboard-interactive)

The server first tries to authenticate you by public key. That doesn't work (I guess you haven't set one up), so it then falls back to 'keyboard-interactive'. It should then ask you for a password, which presumably you're not getting right. Did you see a password prompt?

What is function overloading and overriding in php?

Function overloading occurs when you define the same function name twice (or more) using different set of parameters. For example:

class Addition {
  function compute($first, $second) {
    return $first+$second;

  function compute($first, $second, $third) {
    return $first+$second+$third;

In the example above, the function compute is overloaded with two different parameter signatures. *This is not yet supported in PHP. An alternative is to use optional arguments:

class Addition {
  function compute($first, $second, $third = 0) {
    return $first+$second+$third;

Function overriding occurs when you extend a class and rewrite a function which existed in the parent class:

class Substraction extends Addition {
  function compute($first, $second, $third = 0) {
    return $first-$second-$third;

For example, compute overrides the behavior set forth in Addition.

Unsuccessful append to an empty NumPy array

numpy.append is pretty different from list.append in python. I know that's thrown off a few programers new to numpy. numpy.append is more like concatenate, it makes a new array and fills it with the values from the old array and the new value(s) to be appended. For example:

import numpy

old = numpy.array([1, 2, 3, 4])
new = numpy.append(old, 5)
print old
# [1, 2, 3, 4]
print new
# [1, 2, 3, 4, 5]
new = numpy.append(new, [6, 7])
print new
# [1, 2, 3, 4, 5, 6, 7]

I think you might be able to achieve your goal by doing something like:

result = numpy.zeros((10,))
result[0:2] = [1, 2]

# Or
result = numpy.zeros((10, 2))
result[0, :] = [1, 2]


If you need to create a numpy array using loop, and you don't know ahead of time what the final size of the array will be, you can do something like:

import numpy as np

a = np.array([0., 1.])
b = np.array([2., 3.])

temp = []
while True:
    rnd = random.randint(0, 100)
    if rnd > 50:
    if rnd == 0:

 result = np.array(temp)

In my example result will be an (N, 2) array, where N is the number of times the loop ran, but obviously you can adjust it to your needs.

new update

The error you're seeing has nothing to do with types, it has to do with the shape of the numpy arrays you're trying to concatenate. If you do np.append(a, b) the shapes of a and b need to match. If you append an (2, n) and (n,) you'll get a (3, n) array. Your code is trying to append a (1, 0) to a (2,). Those shapes don't match so you get an error.

Invoking JavaScript code in an iframe from the parent page

If you want to invoke the JavaScript function on the Parent from the iframe generated by another function ex shadowbox or lightbox.

You should try to make use of window object and invoke parent function:


Combine two pandas Data Frames (join on a common column)

Joining fails if the DataFrames have some column names in common. The simplest way around it is to include an lsuffix or rsuffix keyword like so:

restaurant_review_frame.join(restaurant_ids_dataframe, on='business_id', how='left', lsuffix="_review")

This way, the columns have distinct names. The documentation addresses this very problem.

Or, you could get around this by simply deleting the offending columns before you join. If, for example, the stars in restaurant_ids_dataframe are redundant to the stars in restaurant_review_frame, you could del restaurant_ids_dataframe['stars'].

Why does the 'int' object is not callable error occur when using the sum() function?

You probably redefined your "sum" function to be an integer data type. So it is rightly telling you that an integer is not something you can pass a range.

To fix this, restart your interpreter.

Python 2.7.3 (default, Apr 20 2012, 22:44:07) 
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> data1 = range(0, 1000, 3)
>>> data2 = range(0, 1000, 5)
>>> data3 = list(set(data1 + data2)) # makes new list without duplicates
>>> total = sum(data3) # calculate sum of data3 list's elements
>>> print total

If you shadow the sum builtin, you can get the error you are seeing

>>> sum = 0
>>> total = sum(data3) # calculate sum of data3 list's elements
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'int' object is not callable

Also, note that sum will work fine on the set there is no need to convert it to a list

How to generate unique IDs for form labels in React?

I found an easy solution like this:

class ToggleSwitch extends Component {
  static id;

  constructor(props) {

    if (typeof === 'undefined') { = 0;
    } else { += 1;
    } =;

  render() {
    return (
        <input id={`prefix-${}`} />

How to convert a python numpy array to an RGB image with Opencv 2.4?

The size of your image is not sufficient to see in a naked eye. So please try to use atleast 50x50

import cv2 as cv
import numpy as np

black_screen = np.zeros([50,50,3])

black_screen[:, :, 2] = np.ones([50,50])*64/255.0
cv.imshow("Simple_black", black_screen)

Failed to authenticate on SMTP server error using gmail

If you still get this error when sending email: "Failed to authenticate on SMTP server with username "[email protected]" using 3 possible authenticators"

You may try one of these methods:

Go to, click continue and unlock your account for access through other media/sites.

Use double quote for your password: like - "Abc@%$67eSDu"

How to insert selected columns from a CSV file to a MySQL database using LOAD DATA INFILE

For those who have the following error:

Error Code: 1290. The MySQL server is running with the --secure-file-priv option so it cannot execute this statement

You can simply run this command to see which folder can load files from:

SHOW VARIABLES LIKE "secure_file_priv";

After that, you have to copy the files in that folder and run the query with LOAD DATA LOCAL INFILE instead of LOAD DATA INFILE.

Test if string is a number in Ruby on Rails

Tl;dr: Use a regex approach. It is 39x faster than the rescue approach in the accepted answer and also handles cases like "1,000"

def regex_is_number? string
  no_commas =  string.gsub(',', '')
  matches = no_commas.match(/-?\d+(?:\.\d+)?/)
  if !matches.nil? && matches.size == 1 && matches[0] == no_commas


The accepted answer by @Jakob S works for the most part, but catching exceptions can be really slow. In addition, the rescue approach fails on a string like "1,000".

Let's define the methods:

def rescue_is_number? string
  true if Float(string) rescue false

def regex_is_number? string
  no_commas =  string.gsub(',', '')
  matches = no_commas.match(/-?\d+(?:\.\d+)?/)
  if !matches.nil? && matches.size == 1 && matches[0] == no_commas

And now some test cases:

test_cases = {
  true => ["5.5", "23", "-123", "1,234,123"],
  false => ["hello", "99designs", "(123)456-7890"]

And a little code to run the test cases:

test_cases.each do |expected_answer, cases|
  cases.each do |test_case|
    if rescue_is_number?(test_case) != expected_answer
      puts "**rescue_is_number? got #{test_case} wrong**"
      puts "rescue_is_number? got #{test_case} right"

    if regex_is_number?(test_case) != expected_answer
      puts "**regex_is_number? got #{test_case} wrong**"
      puts "regex_is_number? got #{test_case} right"

Here is the output of the test cases:

rescue_is_number? got 5.5 right
regex_is_number? got 5.5 right
rescue_is_number? got 23 right
regex_is_number? got 23 right
rescue_is_number? got -123 right
regex_is_number? got -123 right
**rescue_is_number? got 1,234,123 wrong**
regex_is_number? got 1,234,123 right
rescue_is_number? got hello right
regex_is_number? got hello right
rescue_is_number? got 99designs right
regex_is_number? got 99designs right
rescue_is_number? got (123)456-7890 right
regex_is_number? got (123)456-7890 right

Time to do some performance benchmarks:

Benchmark.ips do |x|"rescue") { test_cases.values.flatten.each { |c| rescue_is_number? c } }"regex") { test_cases.values.flatten.each { |c| regex_is_number? c } }!

And the results:

Calculating -------------------------------------
              rescue   128.000  i/100ms
               regex     4.649k i/100ms
              rescue      1.348k (±16.8%) i/s -      6.656k
               regex     52.113k (± 7.8%) i/s -    260.344k

               regex:    52113.3 i/s
              rescue:     1347.5 i/s - 38.67x slower

CSS: how to position element in lower right?

Set the CSS position: relative; on the box. This causes all absolute positions of objects inside to be relative to the corners of that box. Then set the following CSS on the "Bet 5 days ago" line:

position: absolute;
bottom: 0;
right: 0;

If you need to space the text farther away from the edge, you could change 0 to 2px or similar.

Select info from table where row has max date

SELECT group,MAX(date) as max_date
FROM table
WHERE checks>0
GROUP BY group

That works to get the max date..join it back to your data to get the other columns:

Select group,max_date,checks
from table t
inner join 
(SELECT group,MAX(date) as max_date
FROM table
WHERE checks>0
GROUP BY group)a
on = and a.max_date = date

Inner join functions as the filter to get the max record only.

FYI, your column names are horrid, don't use reserved words for columns (group, date, table).

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

If none of the other answers work for you, and you received this error:

mysqld_safe Logging to '/var/log/mysql/error.log'.
mysqld_safe Directory '/var/run/mysqld' for UNIX socket file don't exists.
[1]+  Exit 1                  sudo mysqld_safe --skip-grant-tables

Follow the below commands step by step until you reset your password:

# Stop Your Server First
sudo service mysql stop

# Make MySQL service directory.
sudo mkdir /var/run/mysqld

# Give MySQL permission to work with the created directory
sudo chown mysql: /var/run/mysqld

# Start MySQL, without permission and network checking
sudo mysqld_safe --skip-grant-tables --skip-networking &

# Log in to your server without any password.
mysql -u root mysql

# Update the password for the root user:
UPDATE mysql.user SET authentication_string=PASSWORD('YourNewPasswordBuddy'), plugin='mysql_native_password' WHERE User='root' AND Host='localhost';

#if you omit (AND Host='localhost') section, it updates the root pass regardless of its host


#kill mysqld_safe process
sudo service mysql restart

#Now you can use your new password to login to your Server
mysql -u root -p

#take note for remote access you should create a remote user and then grant all privileges to that remote user

React-Router External link

I actually ended up building my own Component. <Redirect> It takes info from the react-router element so I can keep it in my routes. Such as:

  component={ Redirect }

Here is my component incase-anyone is curious:

import React, { Component } from "react";

export class Redirect extends Component {
  constructor( props ){
    this.state = { ...props };
    window.location = this.state.route.loc;
    return (<section>Redirecting...</section>);

export default Redirect;

EDIT -- NOTE: This is with react-router: 3.0.5, it is not so simple in 4.x

Googlemaps API Key for Localhost

Guess I'm a bit late to the party, and although I agree that creating a seperate key for development (localhost) and product it is possible to do both in only 1 key.

When you use Application restrictions -> http referers -> Website restricitions you can enter wildcard urls.

However using a wildcard like .localhost/ or .localhost:{port}. (when already having* ) don't seem to work.

Just putting a single * does work but this basicly gives you an unlimited key which is not what you want either.

When you include the full path withhout using the wildcard * it also works, so in my case putting:


Makes the Google maps work both local as on using the same API key.

Anyway when having 2 seperate keys is also an option I would advise to do that.

How to increase the vertical split window size in Vim

This is what I am using as of now:

nnoremap <silent> <Leader>= :exe "resize " . (winheight(0) * 3/2)<CR>
nnoremap <silent> <Leader>- :exe "resize " . (winheight(0) * 2/3)<CR>
nnoremap <silent> <Leader>0 :exe "vertical resize " . (winwidth(0) * 3/2)<CR>
nnoremap <silent> <Leader>9 :exe "vertical resize " . (winwidth(0) * 2/3)<CR>

How do I set the rounded corner radius of a color drawable using xml?

Try below code

<shape xmlns:android="">
    android:topRightRadius="30dp" />
<solid android:color="#1271BB" />

    android:color="#1271BB" />

    android:top="1dp" /></shape>

Python SQL query string formatting

Sorry for posting to such an old thread -- but as someone who also shares a passion for pythonic 'best', I thought I'd share our solution.

The solution is to build SQL statements using python's String Literal Concatenation (, which could be qualified a somewhere between Option 2 and Option 4

Code Sample:

sql = ("SELECT field1, field2, field3, field4 "
       "FROM table "
       "WHERE condition1=1 "
       "AND condition2=2;")

Works as well with f-strings:

fields = "field1, field2, field3, field4"
table = "table"
conditions = "condition1=1 AND condition2=2"

sql = (f"SELECT {fields} "
       f"FROM {table} "
       f"WHERE {conditions};")


  1. It retains the pythonic 'well tabulated' format, but does not add extraneous space characters (which pollutes logging).
  2. It avoids the backslash continuation ugliness of Option 4, which makes it difficult to add statements (not to mention white-space blindness).
  3. And further, it's really simple to expand the statement in VIM (just position the cursor to the insert point, and press SHIFT-O to open a new line).

Inserting the same value multiple times when formatting a string

Depends on what you mean by better. This works if your goal is removal of redundancy.

string='%s bar baz %s bar baz %s bar baz' % (3*(s,))

Python list directory, subdirectory, and files

Since every example here is just using walk (with join), i'd like to show a nice example and comparison with listdir:

import os, time

def listFiles1(root): # listdir
    allFiles = []; walk = [root]
    while walk:
        folder = walk.pop(0)+"/"; items = os.listdir(folder) # items = folders + files
        for i in items: i=folder+i; (walk if os.path.isdir(i) else allFiles).append(i)
    return allFiles

def listFiles2(root): # listdir/join (takes ~1.4x as long) (and uses '\\' instead)
    allFiles = []; walk = [root]
    while walk:
        folder = walk.pop(0); items = os.listdir(folder) # items = folders + files
        for i in items: i=os.path.join(folder,i); (walk if os.path.isdir(i) else allFiles).append(i)
    return allFiles

def listFiles3(root): # walk (takes ~1.5x as long)
    allFiles = []
    for folder, folders, files in os.walk(root):
        for file in files: allFiles+=[folder.replace("\\","/")+"/"+file] # folder+"\\"+file still ~1.5x
    return allFiles

def listFiles4(root): # walk/join (takes ~1.6x as long) (and uses '\\' instead)
    allFiles = []
    for folder, folders, files in os.walk(root):
        for file in files: allFiles+=[os.path.join(folder,file)]
    return allFiles

for i in range(100): files = listFiles1("src") # warm up

start = time.time()
for i in range(100): files = listFiles1("src") # listdir
print("Time taken: %.2fs"%(time.time()-start)) # 0.28s

start = time.time()
for i in range(100): files = listFiles2("src") # listdir and join
print("Time taken: %.2fs"%(time.time()-start)) # 0.38s

start = time.time()
for i in range(100): files = listFiles3("src") # walk
print("Time taken: %.2fs"%(time.time()-start)) # 0.42s

start = time.time()
for i in range(100): files = listFiles4("src") # walk and join
print("Time taken: %.2fs"%(time.time()-start)) # 0.47s

So as you can see for yourself, the listdir version is much more efficient. (and that join is slow)

What is the difference between the HashMap and Map objects in Java?

Map is interface and Hashmap is a class that implements Map Interface

How can I create a UIColor from a hex string?

self.view.backgroundColor = colorWithHex(hex: yourColorCode)
  • Code for creating Color from hexaDecimalCode
func colorWithHex (hex:String) -> UIColor {
    var cString:String = hex.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()

    if (cString.hasPrefix("#")) {
        cString.remove(at: cString.startIndex)

    if ((cString.count) != 6) {
        return UIColor.gray

    var rgbValue:UInt32 = 0
    Scanner(string: cString).scanHexInt32(&rgbValue)

    return UIColor(
        red: CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0,
        green: CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0,
        blue: CGFloat(rgbValue & 0x0000FF) / 255.0,
        alpha: CGFloat(1.0)

Are there any standard exit status codes in Linux?

Part 1: Advanced Bash Scripting Guide

As always, the Advanced Bash Scripting Guide has great information: (This was linked in another answer, but to a non-canonical URL.)

1: Catchall for general errors
2: Misuse of shell builtins (according to Bash documentation)
126: Command invoked cannot execute
127: "command not found"
128: Invalid argument to exit
128+n: Fatal error signal "n"
255: Exit status out of range (exit takes only integer args in the range 0 - 255)

Part 2: sysexits.h

The ABSG references sysexits.h.

On Linux:

$ find /usr -name sysexits.h
$ cat /usr/include/sysexits.h

 * Copyright (c) 1987, 1993
 *  The Regents of the University of California.  All rights reserved.

 (A whole bunch of text left out.)

#define EX_OK           0       /* successful termination */
#define EX__BASE        64      /* base value for error messages */
#define EX_USAGE        64      /* command line usage error */
#define EX_DATAERR      65      /* data format error */
#define EX_NOINPUT      66      /* cannot open input */    
#define EX_NOUSER       67      /* addressee unknown */    
#define EX_NOHOST       68      /* host name unknown */
#define EX_UNAVAILABLE  69      /* service unavailable */
#define EX_SOFTWARE     70      /* internal software error */
#define EX_OSERR        71      /* system error (e.g., can't fork) */
#define EX_OSFILE       72      /* critical OS file missing */
#define EX_CANTCREAT    73      /* can't create (user) output file */
#define EX_IOERR        74      /* input/output error */
#define EX_TEMPFAIL     75      /* temp failure; user is invited to retry */
#define EX_PROTOCOL     76      /* remote error in protocol */
#define EX_NOPERM       77      /* permission denied */
#define EX_CONFIG       78      /* configuration error */

#define EX__MAX 78      /* maximum listed value */

How to redirect Valgrind's output to a file?

You can also set the options --log-fd if you just want to read your logs with a less. For example :

valgrind --log-fd=1 ls | less

Axios having CORS issue

your server should enable the cross origin requests, not the client. To do this, you can check this nice page with implementations and configurations for multiple platforms

Google Maps V3 marker with label

I doubt the standard library supports this.

But you can use the google maps utility library:

var myLatlng = new google.maps.LatLng(-25.363882,131.044922);

var myOptions = {
    zoom: 8,
    center: myLatlng,
    mapTypeId: google.maps.MapTypeId.ROADMAP

map = new google.maps.Map(document.getElementById('map_canvas'), myOptions);

var marker = new MarkerWithLabel({
   position: myLatlng,
   map: map,
   draggable: true,
   raiseOnDrag: true,
   labelContent: "A",
   labelAnchor: new google.maps.Point(3, 30),
   labelClass: "labels", // the CSS class for the label
   labelInBackground: false

The basics about marker can be found here:

Microsoft SQL Server 2005 service fails to start

I agree with Greg that the log is the best place to start. We've experienced something similar and the fix was to ensure that admins have full permissions to the registry location HKLM\System\CurrentControlSet\Control\WMI\Security prior to starting the installation. HTH.

correct PHP headers for pdf file download

There are some things to be considered in your code.

First, write those headers correctly. You will never see any server sending Content-type:application/pdf, the header is Content-Type: application/pdf, spaced, with capitalized first letters etc.

The file name in Content-Disposition is the file name only, not the full path to it, and altrough I don't know if its mandatory or not, this name comes wrapped in " not '. Also, your last ' is missing.

Content-Disposition: inline implies the file should be displayed, not downloaded. Use attachment instead.

In addition, make the file extension in upper case to make it compatible with some mobile devices. (Update: Pretty sure only Blackberries had this problem, but the world moved on from those so this may be no longer a concern)

All that being said, your code should look more like this:


    $filename = './pdf/jobs/pdffile.pdf';

    $fileinfo = pathinfo($filename);
    $sendname = $fileinfo['filename'] . '.' . strtoupper($fileinfo['extension']);

    header('Content-Type: application/pdf');
    header("Content-Disposition: attachment; filename=\"$sendname\"");
    header('Content-Length: ' . filesize($filename));

Content-Length is optional but is also important if you want the user to be able to keep track of the download progress and detect if the download was interrupted. But when using it you have to make sure you won't be send anything along with the file data. Make sure there is absolutely nothing before <?php or after ?>, not even an empty line.

selectOneMenu ajax events

Be carefull that the page does not contain any empty component which has "required" attribute as "true" before your selectOneMenu component running.
If you use a component such as

<p:inputText label="Nm:" id="id_name" value="#{}" required="true"/>


<p:selectOneMenu .....></p:selectOneMenu>

and forget to fill the required component, ajax listener of selectoneMenu cannot be executed.

Alternative to header("Content-type: text/xml");

No. You can't send headers after they were sent. Try to use hooks in wordpress

Passing a variable from node.js to html

I have achieved this by a http API node request which returns required object from node object for HTML page at client ,

for eg: API: localhost:3000/username

returns logged in user from cache by node App object .

node route file,

app.get('/username', function(req, res) {
    res.json({ udata: req.session.user });

How do you deploy Angular apps?

Simple answer. Use the Angular CLI and issue the

ng build 

command in the root directory of your project. The site will be created in the dist directory and you can deploy that to any web server.

This will build for test, if you have production settings in your app you should use

ng build --prod

This will build the project in the dist directory and this can be pushed to the server.

Much has happened since I first posted this answer. The CLI is finally at a 1.0.0 so following this guide go upgrade your project should happen before you try to build.

How To Save Canvas As An Image With canvas.toDataURL()?

Similar to 1000Bugy's answer but simpler because you don't have to make an anchor on the fly and dispatch a click event manually (plus an IE fix).

If you make your download button an anchor you can highjack it right before the default anchor functionality is run. So onAnchorClick you can set the anchor href to the canvas base64 image and the anchor download attribute to whatever you want to name your image.

This does not work in (the current) IE because it doesn't implement the download attribute and prevents download of data uris. But this can be fixed by using window.navigator.msSaveBlob instead.

So your anchor click event handler would be as followed (where anchor, canvas and fileName are scope lookups):

function onClickAnchor(e) {
  if (window.navigator.msSaveBlob) {
    window.navigator.msSaveBlob(canvas.msToBlob(), fileName);
  } else {
    anchor.setAttribute('download', fileName);
    anchor.setAttribute('href', canvas.toDataURL());

Here's a fiddle

How should I validate an e-mail address?

Since API 8 (android 2.2) there is a pattern: android.util.Patterns.EMAIL_ADDRESS

So you can use it to validate yourEmailString:

private boolean isValidEmail(String email) {
    Pattern pattern = Patterns.EMAIL_ADDRESS;
    return pattern.matcher(email).matches();

returns true if the email is valid

UPD: This pattern source code is:

public static final Pattern EMAIL_ADDRESS
    = Pattern.compile(
        "[a-zA-Z0-9\\+\\.\\_\\%\\-\\+]{1,256}" +
        "\\@" +
        "[a-zA-Z0-9][a-zA-Z0-9\\-]{0,64}" +
        "(" +
            "\\." +
            "[a-zA-Z0-9][a-zA-Z0-9\\-]{0,25}" +

refer to:

So you can build it yourself for compatibility with API < 8.

How do I add a Fragment to an Activity with a programmatically created content view

This may help you

Defining a Fragment

create xml file for fragment view fragment_abc.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android=""
android:layout_width="match_parent" android:layout_height="match_parent"
android:orientation="vertical" >

    android:text="TextView" />

    android:text="Button" />


create fragment


public class FooFragment extends Fragment {
// The onCreateView method is called when Fragment should create its View object hierarchy,
// either dynamically or via XML layout inflation. 

public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle 
savedInstanceState) {
    // Defines the xml file for the fragment
    return inflater.inflate(R.layout.fragment_abc, parent, false);

// This event is triggered soon after onCreateView().
// Any view setup should occur here.  E.g., view lookups and attaching view listeners.
public void onViewCreated(View view, Bundle savedInstanceState) {
    // Setup any handles to view objects here
    // EditText etFoo = (EditText) view.findViewById(;

Add frameLayout in your activity


now in activity, add following method

protected void setFragment() {
    // Begin the transaction
    FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
    // Replace the contents of the container with the new fragment
    ft.replace(, new ABCFragment());
    // or ft.add(, new ABCFragment());
    // Complete the changes added above

reference :

Transpose a data frame

Take advantage of as.matrix:

# keep the first column 
names <-  df.aree[,1]

# Transpose everything other than the first column
df.aree.T <-[,-1])))

# Assign first column as the column names of the transposed dataframe
colnames(df.aree.T) <- names

How do I mock a class without an interface?

I think it's better to create an interface for that class. And create a unit test using interface.

If it you don't have access to that class, you can create an adapter for that class.

For example:

public class RealClass
    int DoSomething(string input)
        // real implementation here

public interface IRealClassAdapter
    int DoSomething(string input);

public class RealClassAdapter : IRealClassAdapter
    readonly RealClass _realClass;

    public RealClassAdapter() => _realClass = new RealClass();

    int DoSomething(string input) => _realClass.DoSomething(input);

This way, you can easily create mock for your class using IRealClassAdapter.

Hope it works.

Foreign Key to non-primary key

As others have pointed out, ideally, the foreign key would be created as a reference to a primary key (usually an IDENTITY column). However, we don't live in an ideal world, and sometimes even a "small" change to a schema can have significant ripple effects to the application logic.

Consider the case of a Customer table with a SSN column (and a dumb primary key), and a Claim table that also contains a SSN column (populated by business logic from the Customer data, but no FK exists). The design is flawed, but has been in use for several years, and three different applications have been built on the schema. It should be obvious that ripping out Claim.SSN and putting in a real PK-FK relationship would be ideal, but would also be a significant overhaul. On the other hand, putting a UNIQUE constraint on Customer.SSN, and adding a FK on Claim.SSN, could provide referential integrity, with little or no impact on the applications.

Don't get me wrong, I'm all for normalization, but sometimes pragmatism wins over idealism. If a mediocre design can be helped with a band-aid, surgery might be avoided.

How to move git repository with all branches from bitbucket to github?

I had the reverse use case of importing an existing repository from github to bitbucket.

Bitbucket offers an Import tool as well. The only necessary step is to add URL to repository.

It looks like:

Screenshot of the bitbucket import tool

Set a button background image iPhone programmatically

In one line we can set image with this code

[buttonName setBackgroundImage:[UIImage imageNamed:@"imageName"] forState:UIControlStateNormal];

FormsAuthentication.SignOut() does not log the user out

Be aware that WIF refuses to tell the browser to cleanup the cookies if the wsignoutcleanup message from STS doesn't match the url with the name of the application from IIS, and I mean CASE SENSITIVE. WIF responds with the green OK check, but will not send the command to delete cookies to browser.

So, you need to pay attention to the case sensitivity of your url's.

For example, ThinkTecture Identity Server saves the urls of the visiting RPs in one cookie, but it makes all of them lower case. WIF will receive the wsignoutcleanup message in lower case and will compare it with the application name in IIS. If it doesn't match, it deletes no cookies, but will report OK to the browser. So, for this Identity Server I needed to write all urls in web.config and all application names in IIS in lower case, in order to avoid such problems.

Also don't forget to allow third party cookies in the browser if you have the applications outside of the subdomain of STS, otherwise the browser will not delete the cookies even if WIF tells him so.

Get remote registry value

If you need user's SID and browse remote HKEY_USERS folder, you can follow this script :

<# Replace following with yours and userAccountName with remote username #>
$userLogin = New-Object System.Security.Principal.NTAccount(““,”userAccountName“)
$userSID = $userLogin.Translate([System.Security.Principal.SecurityIdentifier])

<# We will open HKEY_USERS and with accurate user’s SID from remoteComputer #>
$remoteRegistry = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey(‘Users’,”remoteComputer“)

<# We will then retrieve LocalName value from Control Panel / International subkeys #>

$key = $userSID.value+”\Control Panel\International”
$openKey = $remoteRegistry.OpenSubKey($key)

<# We can now retrieve any values #>

$localName = $openKey.GetValue(‘LocaleName’)

Source :

Using in my project (Eclipse)

I did what FD_ said and it crashed with errors as it was looking for "Landroid/support/v7/cardview/R$styleable;", which was not compiled with it

If you really want to use CardView before in eclipse before it gets its own library, you can extract the classes from the classes.jar, copy and paste them into your project, with the values.xml from above from Android Studio and change all the references to to yourpackagename.R in the copied classes. This worked and ran for me

Docker compose, running containers in net:host

you can try just add

network_mode: "host"

example :

version: '2'
    build: web
    - ""
    network_mode: "host"

list option available

network_mode: "bridge"
network_mode: "host"
network_mode: "none"
network_mode: "service:[service name]"
network_mode: "container:[container name/id]"

Finding and removing non ascii characters from an Oracle Varchar2

I had a similar issue and blogged about it here. I started with the regular expression for alpha numerics, then added in the few basic punctuation characters I liked:

select dump(a,1016), a, b
 (select regexp_replace(COLUMN,'[[:alnum:]/''%()> -.:=;[]','') a,
         COLUMN b
  from TABLE)
where a is not null
order by a;

I used dump with the 1016 variant to give out the hex characters I wanted to replace which I could then user in a utl_raw.cast_to_varchar2.

Showing/Hiding Table Rows with Javascript - can do with ID - how to do with Class?

JQuery 10.1.2 has a nice show and hide functions that encapsulate the behavior you are talking about. This would save you having to write a new function or keep track of css classes.



w3cSchool link to JQuery show and hide

How do I declare an array variable in VBA?

As pointed out by others, your problem is that you have not declared an array

Below I've tried to recreate your program so that it works as you intended. I tried to leave as much as possible as it was (such as leaving your array as a variant)

Public Sub Testprog()
    '"test()" is an array, "test" is not
    Dim test() As Variant
    'I am assuming that iCounter is the array size
    Dim iCounter As Integer

    '"On Error Resume Next" just makes us skip over a section that throws the error
    On Error Resume Next

    'if test() has not been assigned a UBound or LBound yet, calling either will throw an error
    '   without an LBound and UBound an array won't hold anything (we will assign them later)

    'Array size can be determined by (UBound(test) - LBound(test)) + 1
    If (UBound(test) - LBound(test)) + 1 > 0 Then
        iCounter = (UBound(test) - LBound(test)) + 1

        'So that we don't run the code that deals with UBound(test) throwing an error
        Exit Sub
    End If

    'All the code below here will run if UBound(test)/LBound(test) threw an error
    iCounter = 0

    'This makes LBound(test) = 0
    '   and UBound(test) = iCounter where iCounter is 0
    '   Which gives us one element at test(0)
    ReDim Preserve test(0 To iCounter)

    test(iCounter) = "test"
End Sub

How to compare DateTime in C#?

MuSTaNG's answer says it all, but I am still adding it to make it a little more elaborate, with links and all.

The conventional operators

are available for DateTime since .NET Framework 1.1. Also, addition and subtraction of DateTime objects are also possible using conventional operators + and -.

One example from MSDN:

System.DateTime april19 = new DateTime(2001, 4, 19);
System.DateTime otherDate = new DateTime(1991, 6, 5);

// areEqual gets false.
bool areEqual = april19 == otherDate;

otherDate = new DateTime(2001, 4, 19);
// areEqual gets true.
areEqual = april19 == otherDate;

Other operators can be used likewise.

Here is the list all operators available for DateTime.