Programs & Examples On #Mime filter

In Java, what is the best way to determine the size of an object?

Just use java visual VM.

It has everything you need to profile and debug memory problems.

It also has a OQL (Object Query Language) console which allows you to do many useful things, one of which being sizeof(o)

how to do file upload using jquery serialization

$(document).on('click', '#submitBtn', function(e){
var form = $("#myForm").closest("form");
var formData = new FormData(form[0]);
    type: "POST",
    data: formData,
    dataType: "json",
    url: form.attr('action'),
    processData: false,
    contentType: false,
    success: function(data) {
         alert('Sucess! Form data posted with file type of input also!');

By making use of new FormData() and setting processData: false, contentType:false in ajax call submission of form with file input worked for me

Using above code I am able to submit form data with file field also through Ajax

What's the bad magic number error?

The magic number comes from UNIX-type systems where the first few bytes of a file held a marker indicating the file type.

Python puts a similar marker into its pyc files when it creates them.

Then the python interpreter makes sure this number is correct when loading it.

Anything that damages this magic number will cause your problem. This includes editing the pyc file or trying to run a pyc from a different version of python (usually later) than your interpreter.

If they are your pyc files, just delete them and let the interpreter re-compile the py files. On UNIX type systems, that could be something as simple as:

rm *.pyc


find . -name '*.pyc' -delete

If they are not yours, you'll have to either get the py files for re-compilation, or an interpreter that can run the pyc files with that particular magic value.

One thing that might be causing the intermittent nature. The pyc that's causing the problem may only be imported under certain conditions. It's highly unlikely it would import sometimes. You should check the actual full stack trace when the import fails?

As an aside, the first word of all my 2.5.1(r251:54863) pyc files is 62131, 2.6.1(r261:67517) is 62161. The list of all magic numbers can be found in Python/import.c, reproduced here for completeness (current as at the time the answer was posted, it may have changed since then):

1.5:   20121
1.5.1: 20121
1.5.2: 20121
1.6:   50428
2.0:   50823
2.0.1: 50823
2.1:   60202
2.1.1: 60202
2.1.2: 60202
2.2:   60717
2.3a0: 62011
2.3a0: 62021
2.3a0: 62011
2.4a0: 62041
2.4a3: 62051
2.4b1: 62061
2.5a0: 62071
2.5a0: 62081
2.5a0: 62091
2.5a0: 62092
2.5b3: 62101
2.5b3: 62111
2.5c1: 62121
2.5c2: 62131
2.6a0: 62151
2.6a1: 62161
2.7a0: 62171

How to respond with HTTP 400 error in a Spring MVC @ResponseBody method returning String?

I m using this in my spring boot application

@RequestMapping(value = "/matches/{matchId}", produces = "application/json")
public ResponseEntity<?> match(@PathVariable String matchId, @RequestBody String body,
            HttpServletRequest request, HttpServletResponse response) {

    Product p;
    try {
      p = service.getProduct(request.getProductId());
    } catch(Exception ex) {
       return new ResponseEntity<String>(HttpStatus.BAD_REQUEST);

    return new ResponseEntity(p, HttpStatus.OK);

How to uninstall a Windows Service when there is no executable for it left on the system?

My favourite way of doing this is to use Sysinternals Autoruns application. Just select the service and press delete.

Tomcat is not running even though JAVA_HOME path is correct

there are two types of environment variable first User variable if you path in this it will work for that particular user only. second is System variable if you set path in this it is used by all type of users.. In my system i set JAVA_HOME in system variable,it was not working,then i set path in User variable it is try in both type of environment variable...

GET URL parameter in PHP

$_GET is not a function or language construct—it's just a variable (an array). Try:

echo $_GET['link'];

In particular, it's a superglobal: a built-in variable that's populated by PHP and is available in all scopes (you can use it from inside a function without the global keyword).

Since the variable might not exist, you could (and should) ensure your code does not trigger notices with:

if (isset($_GET['link'])) {
    echo $_GET['link'];
} else {
    // Fallback behaviour goes here

Alternatively, if you want to skip manual index checks and maybe add further validations you can use the filter extension:

echo filter_input(INPUT_GET, 'link', FILTER_SANITIZE_URL);

Last but not least, you can use the null coalescing operator (available since PHP/7.0) to handle missing parameters:

echo $_GET['link'] ?? 'Fallback value';

MySQL Workbench - Connect to a Localhost

I had this problem and I just realized that if in the server you see the user in the menu SERVER -> USERS AND PRIVILEGES and find the user who has % as HOSTNAME, you can use it instead the root user.

That's all

force client disconnect from server with and nodejs

use :

socket.Disconnect() //ok

do not use :


How to write both h1 and h2 in the same line?

In many cases,


is enough.

But in some cases, you have to add following:


"cannot be used as a function error"

You can't pass a function as a parameter. Simply remove it from estimatedPopulation() and replace it with 'float growthRate'. use this in your calculation instead of calling the function:

int estimatedPopulation (int currentPopulation, float growthRate)
    return (currentPopulation + currentPopulation * growthRate / 100);

and call it as:

int foo = estimatedPopulation (currentPopulation, growthRate (birthRate, deathRate));

rm: cannot remove: Permission denied

The code says everything:

max@serv$ chmod 777 .

Okay, it doesn't say everything.

In UNIX and Linux, the ability to remove a file is not determined by the access bits of that file. It is determined by the access bits of the directory which contains the file.

Think of it this way -- deleting a file doesn't modify that file. You aren't writing to the file, so why should "w" on the file matter? Deleting a file requires editing the directory that points to the file, so you need "w" on the that directory.

Which is more efficient, a for-each loop, or an iterator?

The foreach underhood is creating the iterator, calling hasNext() and calling next() to get the value; The issue with the performance comes only if you are using something that implements the RandomomAccess.

for (Iterator<CustomObj> iter = customList.iterator(); iter.hasNext()){
   CustomObj custObj =;

Performance issues with the iterator-based loop is because it is:

  1. allocating an object even if the list is empty (Iterator<CustomObj> iter = customList.iterator(););
  2. iter.hasNext() during every iteration of the loop there is an invokeInterface virtual call (go through all the classes, then do method table lookup before the jump).
  3. the implementation of the iterator has to do at least 2 fields lookup in order to make hasNext() call figure the value: #1 get current count and #2 get total count
  4. inside the body loop, there is another invokeInterface virtual call go through all the classes and do method table lookup before the jump) and as well has to do fields lookup: #1 get the index and #2 get the reference to the array to do the offset into it (in every iteration).

A potential optimiziation is to switch to an index iteration with the cached size lookup:

for(int x = 0, size = customList.size(); x < size; x++){
  CustomObj custObj = customList.get(x);

Here we have:

  1. one invokeInterface virtual method call customList.size() on the initial creation of the for loop to get the size
  2. the get method call customList.get(x) during the body for loop, which is a field lookup to the array and then can do the offset into the array

We reduced a ton of method calls, field lookups. This you don't want to do with LinkedList or with something that is not a RandomAccess collection obj, otherwise the customList.get(x) is gonna turn into something that has to traverse the LinkedList on every iteration.

This is perfect when you know that is any RandomAccess based list collection.

Get child Node of another Node, given node name

//xn=list of parent nodes......                
foreach (XmlNode xn in xnList)
    foreach (XmlNode child in xn.ChildNodes) 
        if (child.Name.Equals("name")) 
            name = child.InnerText; 
        if (child.Name.Equals("age"))
            age = child.InnerText; 

String comparison in bash. [[: not found

I had this problem when installing Heroku Toolbelt

This is how I solved the problem

$ ls -l /bin/sh
lrwxrwxrwx 1 root root 4 ago 15  2012 /bin/sh -> dash

As you can see, /bin/sh is a link to "dash" (not bash), and [[ is bash syntactic sugarness. So I just replaced the link to /bin/bash. Careful using rm like this in your system!

$ sudo rm /bin/sh
$ sudo ln -s /bin/bash /bin/sh

How to execute a raw update sql with dynamic binding in rails

ActiveRecord::Base.connection has a quote method that takes a string value (and optionally the column object). So you can say this:

  UPDATE  foo
  SET     bar = #{ActiveRecord::Base.connection.quote(baz)}

Note if you're in a Rails migration or an ActiveRecord object you can shorten that to:

  UPDATE  foo
  SET     bar = #{connection.quote(baz)}

UPDATE: As @kolen points out, you should use exec_update instead. This will handle the quoting for you and also avoid leaking memory. The signature works a bit differently though:

connection.exec_update(<<-EOQ, "SQL", [[nil, baz]])
  UPDATE  foo
  SET     bar = $1

Here the last param is a array of tuples representing bind parameters. In each tuple, the first entry is the column type and the second is the value. You can give nil for the column type and Rails will usually do the right thing though.

There are also exec_query, exec_insert, and exec_delete, depending on what you need.

TestNG ERROR Cannot find class in classpath

I just had this problem and was because the skip test option in the run configuration was checked. made that unchecked and build, then run the testNg, worked.

Tools to get a pictorial function call graph of code

Astrée is the most robust and sophisticated tool out there, IMHO.

Why specify @charset "UTF-8"; in your CSS file?

If you're putting a <meta> tag in your css files, you're doing something wrong. The <meta> tag belongs in your html files, and tells the browser how the html is encoded, it doesn't say anything about the css, which is a separate file. You could conceivably have completely different encodings for your html and css, although I can't imagine this would be a good idea.

Use Async/Await with Axios in React.js

Async/Await with axios 

  useEffect(() => {     
    const getData = async () => {  
      await axios.get('your_url')  
      .then(res => {  
      .catch(err => {  
  }, [])

How to convert .pem into .key?

openssl rsa -in privkey.pem -out private.key does the job.

Sheet.getRange(1,1,1,12) what does the numbers in bracket specify?

Found these docu on the google docu pages:

  • row --- int --- top row of the range
  • column --- int--- leftmost column of the range
  • optNumRows --- int --- number of rows in the range.
  • optNumColumns --- int --- number of columns in the range

In your example, you would get (if you picked the 3rd row) "C3:O3", cause C --> O is 12 columns


Using the example on the docu:

// The code below will get the number of columns for the range C2:G8
// in the active spreadsheet, which happens to be "4"
var count = SpreadsheetApp.getActiveSheet().getRange(2, 3, 6, 4).getNumColumns(); Browser.msgBox(count);

The values between brackets:
2: the starting row = 2
3: the starting col = C
6: the number of rows = 6 so from 2 to 8
4: the number of cols = 4 so from C to G

So you come to the range: C2:G8

Mime type for WOFF fonts?

Update from Keith Shaw's comment on Jun 22, 2017:

As of February 2017, RFC8081 is the proposed standard. It defines a top-level media type for fonts, therefore the standard media type for WOFF and WOFF2 are as follows:



In January 2011 it was announced that in the meantime Chromium will recognize


as the mime-type for WOFF. I know this change is now in Chrome beta and if not in stable yet, it shouldn't be too far away.

Load view from an external xib file in storyboard

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


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

Make the swift file the xib file's owner.

enter image description here Code

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

import UIKit
class ResuableCustomView: UIView {

    let nibName = "ReusableCustomView"
    var contentView: UIView?

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

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

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

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

Use it

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

enter image description here

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

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

Here is the protocol you will want to reference:

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

public extension NibLoadable where Self: UIView {

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

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

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

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

class MyCustomClass: UIView, NibLoadable {

    @IBOutlet weak var myLabel: UILabel!

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

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


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

Java 8 lambda get and remove element from list

When we want to get multiple elements from a List into a new list (filter using a predicate) and remove them from the existing list, I could not find a proper answer anywhere.

Here is how we can do it using Java Streaming API partitioning.

Map<Boolean, List<ProducerDTO>> classifiedElements = producersProcedureActive
    .collect(Collectors.partitioningBy(producer -> producer.getPod().equals(pod)));

// get two new lists 
List<ProducerDTO> matching = classifiedElements.get(true);
List<ProducerDTO> nonMatching = classifiedElements.get(false);

// OR get non-matching elements to the existing list
producersProcedureActive = classifiedElements.get(false);

This way you effectively remove the filtered elements from the original list and add them to a new list.

Refer the 5.2. Collectors.partitioningBy section of this article.

Replace multiple whitespaces with single whitespace in JavaScript string

You can augment String to implement these behaviors as methods, as in:

String.prototype.killWhiteSpace = function() {
    return this.replace(/\s/g, '');

String.prototype.reduceWhiteSpace = function() {
    return this.replace(/\s+/g, ' ');

This now enables you to use the following elegant forms to produce the strings you want:

"Get rid of my whitespaces.".killWhiteSpace();
"Get rid of my extra        whitespaces".reduceWhiteSpace();

Alter table add multiple columns ms sql

ADD ( HasPhotoInReadyStorage  bit,
     HasPhotoInWorkStorage  bit,
     HasPhotoInMaterialStorage bit *(Missing ,)*
     HasText  bit);

How can I Insert data into SQL Server using VBNet

Imports System.Data

Imports System.Data.SqlClient

Public Class Form2

Dim myconnection As SqlConnection

Dim mycommand As SqlCommand

Dim dr As SqlDataReader

Dim dr1 As SqlDataReader

Dim ra As Integer

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

    myconnection = New SqlConnection("server=localhost;uid=root;pwd=;database=simple")

    'you need to provide password for sql server


    mycommand = New SqlCommand("insert into tbl_cus([name],[class],[phone],[address]) values ('" & TextBox1.Text & "','" & TextBox2.Text & "','" & TextBox3.Text & "','" & TextBox4.Text & "')", myconnection)


    MessageBox.Show("New Row Inserted" & ra)


End Sub

End Class

Using jQuery UI sortable with HTML tables

You can call sortable on a <tbody> instead of on the individual rows.



$(function() {_x000D_
  $( "tbody" ).sortable();_x000D_
table {_x000D_
    border-spacing: collapse;_x000D_
    border-spacing: 0;_x000D_
td {_x000D_
    width: 50px;_x000D_
    height: 25px;_x000D_
    border: 1px solid black;_x000D_
<link href="//" rel="stylesheet">_x000D_
<script src="//"></script>_x000D_
<script src="//"></script>_x000D_
        <tr> _x000D_
            <td>9</td> _x000D_
        </tr>  _x000D_
    </tbody>    _x000D_

PHP Get Highest Value from Array

Try using asort().

From documentation:

asort - Sort an array and maintain index association


bool asort ( array &$array [, int $sort_flags = SORT_REGULAR ] )

This function sorts an array such that array indices maintain their correlation with the array elements they are associated with. This is used mainly when sorting associative arrays where the actual element order is significant.

How to get previous month and year relative to today, using strtotime and date?

Have a look at the DateTime class. It should do the calculations correctly and the date formats are compatible with strttotime. Something like:

$datestring='2011-03-30 first day of last month';
echo $dt->format('Y-m'); //2011-02

Eclipse: How to install a plugin manually?

  1. Download your plugin
  2. Open Eclipse
  3. From the menu choose: Help / Install New Software...
  4. Click the Add button
  5. In the Add Repository dialog that appears, click the Archive button next to the Location field
  6. Select your plugin file, click OK

You could also just copy plugins to the eclipse/plugins directory, but it's not recommended.

Missing visible-** and hidden-** in Bootstrap v4

Bootstrap 4 to hide whole content use this class '.d-none' it will be hide everything regardless of breakpoints same like previous bootstrap version class '.hidden'

C# Foreach statement does not contain public definition for GetEnumerator

You should implement the IEnumerable interface (CarBootSaleList should impl it in your case).

But it is usually easier to subclass System.Collections.ObjectModel.Collection and friends

Your code also seems a bit strange, like you are nesting lists?

How to stop an unstoppable zombie job on Jenkins without restarting the server?

I guess it is too late to answer but my help some people.

  1. Install the monitoring plugin. (
  2. Go to jenkinsUrl/monitoring/nodes
  3. Go to the Threads section at the bottom
  4. Click on the details button on the left of the master
  5. Sort by User time (ms)
  6. Then look at the name of the thread, you will have the name and number of the build
  7. Kill it

I don't have enough reputation to post images sorry.

Hope it can help

How to make Twitter Bootstrap tooltips have multiple lines?

If you're using Twitter Bootstrap Tooltip on non-link element, you can specify, that you want a multi-line tooltip directly in HTML code, without Javascript, using just the data parameter:

<span rel="tooltip" data-html="true" data-original-title="1<br />2<br />3">5</span>

This is just an alternative version of costales' answer. All the glory goes to him! :]

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

Visual Studio Community is same (almost) as professional edition. What differs is that VS community do not have TFS features, and the licensing is different. As stated by @Stefan.

The different versions on VS are compared here -

enter image description here

For homebrew mysql installs, where's my.cnf?

One way to find out:

sudo /usr/libexec/locate.updatedb
# wait a few minutes for it to finish
locate my.cnf

How to get the row number from a datatable?

If you need the index of the item you're working with then using a foreach loop is the wrong method of iterating over the collection. Change the way you're looping so you have the index:

for(int i = 0; i < dt.Rows.Count; i++)
    // your index is in i
    var row = dt.Rows[i];

How do I parse JSON into an int?

At first, you create a BufferedReader on a FileReader to the file.

Then, you create a new `JSONParser()´ object that parses the content read from the file.

You cast the parsed Object to a JSONObject and get the id field.

FileReader file=new FileReader("1.json");
BufferedReader write=new BufferedReader(file);
Object obj=new JSONParser().parse(write);
JSONObject jo = (JSONObject) obj;
long id=(long)jo.get("id");

How to get box-shadow on left & right sides only


For a nice inset shadow in right and left sides on images, or any other content, use it this way

***The z-index:-1 does a nice trick when showing images or inner objects with insets

<div class="shadowcontainer">
<img src="" class="innercontent" style="with:100%"/>


box-shadow: inset -40px 0px 30px -30px rgba(0,0,0,0.9),inset 40px 0px 30px -30px rgba(0,0,0,0.9);


How to get RegistrationID using GCM in android

Use this code to get Registration ID using GCM

String regId = "", msg = "";

public void getRegisterationID() {

    new AsyncTask() {
        protected Object doInBackground(Object...params) {

            String msg = "";
            try {
                if (gcm == null) {
                    gcm = GoogleCloudMessaging.getInstance(Login.this);
                regId = gcm.register(YOUR_SENDER_ID);
                Log.d("in async task", regId);

                // try
                msg = "Device registered, registration ID=" + regId;

            } catch (IOException ex) {
                msg = "Error :" + ex.getMessage();
            return msg;
    }.execute(null, null, null);

and don't forget to write permissions in manifest...
I hope it helps!

How to create a List with a dynamic object type

It appears you might be a bit confused as to how the .Add method works. I will refer directly to your code in my explanation.

Basically in C#, the .Add method of a List of objects does not COPY new added objects into the list, it merely copies a reference to the object (it's address) into the List. So the reason every value in the list is pointing to the same value is because you've only created 1 new DyObj. So your list essentially looks like this.

DyObjectsList[0] = &DyObj; // pointing to DyObj
DyObjectsList[1] = &DyObj; // pointing to the same DyObj
DyObjectsList[2] = &DyObj; // pointing to the same DyObj


The easiest way to fix your code is to create a new DyObj for every .Add. Putting the new inside of the block with the .Add would accomplish this goal in this particular instance.

var DyObjectsList = new List<dynamic>; 
if (condition1) { 
    dynamic DyObj = new ExpandoObject(); 
    DyObj.Required = true; 
    DyObj.Message = "Message 1"; 
    DyObjectsList .Add(DyObj); 
if (condition2) { 
    dynamic DyObj = new ExpandoObject(); 
    DyObj.Required = false; 
    DyObj.Message = "Message 2"; 
    DyObjectsList .Add(DyObj); 

your resulting List essentially looks like this

DyObjectsList[0] = &DyObj0; // pointing to a DyObj
DyObjectsList[1] = &DyObj1; // pointing to a different DyObj
DyObjectsList[2] = &DyObj2; // pointing to another DyObj

Now in some other languages this approach wouldn't work, because as you leave the block, the objects declared in the scope of the block could go out of scope and be destroyed. Thus you would be left with a collection of pointers, pointing to garbage.

However in C#, if a reference to the new DyObjs exists when you leave the block (and they do exist in your List because of the .Add operation) then C# does not release the memory associated with that pointer. Therefore the Objects you created in that block persist and your List contains pointers to valid objects and your code works.

How to change the name of a Django app?

Follow these steps to change an app's name in Django:

  1. Rename the folder which is in your project root
  2. Change any references to your app in their dependencies, i.e. the app's, , '' , and files.
  3. Edit the database table django_content_type with the following command: UPDATE django_content_type SET app_label='<NewAppName>' WHERE app_label='<OldAppName>'
  4. Also if you have models, you will have to rename the model tables. For postgres use ALTER TABLE <oldAppName>_modelName RENAME TO <newAppName>_modelName. For mysql too I think it is the same (as mentioned by @null_radix)
  5. (For Django >= 1.7) Update the django_migrations table to avoid having your previous migrations re-run: UPDATE django_migrations SET app='<NewAppName>' WHERE app='<OldAppName>'. Note: there is some debate (in comments) if this step is required for Django 1.8+; If someone knows for sure please update here.
  6. If your 's Meta Class has app_name listed, make sure to rename that too (mentioned by @will).
  7. If you've namespaced your static or templates folders inside your app, you'll also need to rename those. For example, rename old_app/static/old_app to new_app/static/new_app.
  8. For renaming django models, you'll need to change entry in DB. For postgreSQL use UPDATE django_content_type SET name='<newModelName>' where name='<oldModelName>' AND app_label='<OldAppName>'

Meta point (If using virtualenv): Worth noting, if you are renaming the directory that contains your virtualenv, there will likely be several files in your env that contain an absolute path and will also need to be updated. If you are getting errors such as ImportError: No module named ... this might be the culprit. (thanks to @danyamachine for providing this).

Other references: you might also want to refer the below links for a more complete picture

  1. Renaming an app with Django and South
  2. How do I migrate a model out of one django app and into a new one?
  3. How to change the name of a Django app?
  4. Backwards migration with Django South
  5. Easiest way to rename a model using Django/South?
  6. Python code (thanks to A.Raouf) to automate the above steps (Untested code. You have been warned!)
  7. Python code (thanks to rafaponieman) to automate the above steps (Untested code. You have been warned!)

Correct use for angular-translate in controllers

To make a translation in the controller you could use $translate service:

$translate(['COMMON.SI', 'COMMON.NO']).then(function (translations) { = translations['COMMON.SI']; = translations['COMMON.NO'];

That statement only does the translation on controller activation but it doesn't detect the runtime change in language. In order to achieve that behavior, you could listen the $rootScope event: $translateChangeSuccess and do the same translation there:

    $rootScope.$on('$translateChangeSuccess', function () {
        $translate(['COMMON.SI', 'COMMON.NO']).then(function (translations) {
   = translations['COMMON.SI'];
   = translations['COMMON.NO'];

Of course, you could encapsulate the $translateservice in a method and call it in the controller and in the $translateChangeSucesslistener.

Repeat each row of data.frame the number of times specified in a column

I know this is not the case but if you need to keep the original freq column, you can use another tidyverse approach together with rep:


df <- data.frame(var1 = c('a', 'b', 'c'), var2 = c('d', 'e', 'f'), freq = 1:3)

df %>% 
  map_df(., rep, .$freq)
#> # A tibble: 6 x 3
#>   var1  var2   freq
#>   <fct> <fct> <int>
#> 1 a     d         1
#> 2 b     e         2
#> 3 b     e         2
#> 4 c     f         3
#> 5 c     f         3
#> 6 c     f         3

Created on 2019-12-21 by the reprex package (v0.3.0)

Get local IP address in Node.js

Here's what might be the cleanest, simplest answer without dependencies & that works across all platforms.

const { lookup } = require('dns').promises;
const { hostname } = require('os');

async function getMyIPAddress(options) {
  return (await lookup(hostname(), options))

Differences between CHMOD 755 vs 750 permissions set

0755 = User:rwx Group:r-x World:r-x

0750 = User:rwx Group:r-x World:--- (i.e. World: no access)

r = read
w = write
x = execute (traverse for directories)

Count number of cells with any value (string or number) in a column in Google Docs Spreadsheet

Shorter and dealing with a column (entire, not just a section of a column):



Beware, a cell containing just a space would be included in the count.

Finding the source code for built-in Python functions?

The iPython shell makes this easy: function? will give you the documentation. function?? shows also the code. BUT this only works for pure python functions.

Then you can always download the source code for the (c)Python.

If you're interested in pythonic implementations of core functionality have a look at PyPy source.

To get total number of columns in a table in sql

It can be done using:-


Why can't Visual Studio find my DLL?

try "configuration properties -> debugging -> environment" and set the PATH variable in run-time

Oracle Add 1 hour in SQL

You can use INTERVAL type or just add calculated number value - "1" is equal "1 day".

first way:

select date_column + INTERVAL '0 01:00:00' DAY TO SECOND from dual;

second way:

select date_column + 1/24 from dual;

First way is more convenient when you need to add a complicated value - for example, "1 day 3 hours 25 minutes 49 seconds". See also:

Also you have to remember that oracle have two interval types - DAY TO SECOND and YEAR TO MONTH. As for me, one interval type would be better, but I hope people in oracle knows, what they do ;)

How do I show the number keyboard on an EditText in android?

Use the below code in java file


What is the difference between a URI, a URL and a URN?



As the image above indicates, there are three distinct components at play here. It’s usually best to go to the source when discussing matters like these, so here’s an exerpt from Tim Berners-Lee, et. al. in RFC 3986: Uniform Resource Identifier (URI): Generic Syntax:

A Uniform Resource Identifier (URI) is a compact sequence of characters that identifies an abstract or physical resource.

A URI can be further classified as a locator, a name, or both. The term “Uniform Resource Locator” (URL) refers to the subset of URIs that, in addition to identifying a resource, provide a means of locating the resource by describing its primary access mechanism (e.g., its network “location”).

Programmatically generate video or animated GIF in Python?

I came upon PIL's ImageSequence module, which offers for a better (and more standard) GIF aninmation. I also use Tk's after() method this time, which is better than time.sleep().

from Tkinter import * 
from PIL import Image, ImageTk, ImageSequence

def stop(event):
  global play
  play = False

root = Tk()
root.bind("<Key>", stop) # Press any key to stop
GIFfile = {path_to_your_GIF_file}
im =; img = ImageTk.PhotoImage(im)
delay =['duration'] # Delay used in the GIF file 
lbl = Label(image=img); lbl.pack() # Create a label where to display images
play = True;
while play:
  for frame in ImageSequence.Iterator(im):
    if not play: break 
    img = ImageTk.PhotoImage(frame)
    lbl.config(image=img); root.update() # Show the new frame/image


Get String in YYYYMMDD format from JS date object?

Altered piece of code I often use:

Date.prototype.yyyymmdd = function() {
  var mm = this.getMonth() + 1; // getMonth() is zero-based
  var dd = this.getDate();

  return [this.getFullYear(),
          (mm>9 ? '' : '0') + mm,
          (dd>9 ? '' : '0') + dd

var date = new Date();

Converting an int or String to a char array on Arduino

None of that stuff worked. Here's a much simpler way .. the label str is the pointer to what IS an array...

String str = String(yourNumber, DEC); // Obviously .. get your int or byte into the string

str = str + '\r' + '\n'; // Add the required carriage return, optional line feed

byte str_len = str.length();

// Get the length of the whole lot .. C will kindly
// place a null at the end of the string which makes
// it by default an array[].
// The [0] element is the highest digit... so we
// have a separate place counter for the array...

byte arrayPointer = 0;

while (str_len)
    // I was outputting the digits to the TX buffer

    if ((UCSR0A & (1<<UDRE0))) // Is the TX buffer empty?
        UDR0 = str[arrayPointer];

Could not load type 'XXX.Global'

Ensure compiled dll of your project placed in proper bin folder.

In my case, when i have changed the compiled directory of our subproject to bin folder of our main project, it worked.

BASH Syntax error near unexpected token 'done'

Open new file named foobar

nano -w foobar

Input script

 while [ 0 = 0 ]; do
   echo "Press [CTRL+C] to stop.."
   sleep 1

Exit and save

CTRL+X then Y and Enter

Set script executable and run

chmod +x foobar

How can I check if a var is a string in JavaScript?

You were close:

if (typeof a_string === 'string') {
    // this is a string

On a related note: the above check won't work if a string is created with new String('hello') as the type will be Object instead. There are complicated solutions to work around this, but it's better to just avoid creating strings that way, ever.

Get $_POST from multiple checkboxes

<input type="checkbox" name="check_list[<? echo $row['Report ID'] ?>]" value="<? echo $row['Report ID'] ?>">

And after the post, you can loop through them:

     foreach($_POST['check_list'] as $report_id){
        echo "$report_id was checked! ";

Or get a certain value posted from previous page:

  echo $report_id . " was checked!<br/>";

Hosting a Maven repository on github

Since 2019 you can now use the new functionality called Github package registry.

Basically the process is:

  • generate a new personal access token from the github settings
  • add repository and token info in your settings.xml
  • deploy using

    mvn deploy -Dregistry= -Dtoken=yor_token  

How to load URL in UIWebView in Swift?

Swift 3 doesn't use NS prefix anymore on URL and URLRequest, so the updated code would be:

let url = URL(string: "your_url_here")
yourWebView.loadRequest(URLRequest(url: url!))

How to make HTML code inactive with comments


<!-- This is a comment for an HTML page and it will not display in the browser -->

For more information, I think 3 On SGML and HTML may help you.

Oracle: SQL query that returns rows with only numeric values

The complete list of the regexp_like and other regexp functions in Oracle 11.1:

In your example:

FROM test
WHERE REGEXP_LIKE(X, '^[[:digit:]]$');

Hibernate error: ids for this class must be manually assigned before calling save():

Resolved this problem using a Sequence ID defined in Oracle database.

ORACLE_DB_SEQ_ID is defined as a sequence for the table. Also look at the console to see the Hibernate SQL that is used to verify.

@Column(name = "MY_ID", unique = true, nullable = false)
@GeneratedValue(strategy=GenerationType.SEQUENCE, generator = "id_Sequence")
@SequenceGenerator(name = "id_Sequence", sequenceName = "ORACLE_DB_SEQ_ID")
Long myId;

Visual c++ can't open include file 'iostream'

If you created an environment variable with the name IncludePath, try renaming it to something else.

This name will override $(IncludePath) inside project properties.

How do I link to Google Maps with a particular longitude and latitude?

Open google map and show URL schemes location and location pin


Entity Framework The underlying provider failed on Open

I had this error and it was caused by a typo in the connection string in App.config.

HTML-parser on Node.js

Try - you give it some HTML and it gives you a DOM.

How to check if a double is null?

To say that something "is null" means that it is a reference to the null value. Primitives (int, double, float, etc) are by definition not reference types, so they cannot have null values. You will need to find out what your database wrapper will do in this case.

Error 415 Unsupported Media Type: POST not reaching REST if JSON, but it does if XML

I get the same issue. In fact, the request didn't reach the jersey annoted method. I solved the problem with add the annotation: @Consumes(MediaType.APPLICATION_FORM_URLENCODED) The annotation @Consumes("/") don't work!

    public void  get__EstNouvelleGH( @Context HttpServletResponse response) {

Could not load file or assembly 'Newtonsoft.Json, Version=, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed'

Apart from many answers here,I found something hence adding it.First point,Make sure the dll is not referenced from GAC.Apart from this,

While adding/changing dll of Newtonsoft.Json ,Sometimes *.csproj of the project doesnt get changed or the changed version of json dll will not be reflected in csproj of the solution.

So Open the project in notepad++ and search Newtonsoft.Json and rename the JSON from old version to New version explicitly.Now after tabbing back to VS ,the solution/project will reload with needed version Newtonsoft.JSON dll.

Let JSON object accept bytes or let urlopen output strings

HTTP sends bytes. If the resource in question is text, the character encoding is normally specified, either by the Content-Type HTTP header or by another mechanism (an RFC, HTML meta http-equiv,...).

urllib should know how to encode the bytes to a string, but it's too naïve—it's a horribly underpowered and un-Pythonic library.

Dive Into Python 3 provides an overview about the situation.

Your "work-around" is fine—although it feels wrong, it's the correct way to do it.

Laravel 5.4 ‘cross-env’ Is Not Recognized as an Internal or External Command

There is the same problem in Linux OS. The issue is related on Windows OS, but Homestead is a Ubuntu VM, and the solution posted works strongly good in others SO. I applied the commands sugested by flik, and the problems was solved. I only used the following commands

I only used the following commands

rm -rf node_modules
npm cache clear --force


npm install cross-env
npm install 
npm run watch

It's working fine on linux Fedora 25.

Selenium using Python - Geckodriver executable needs to be in PATH

On macOS with Homebrew already installed you can simply run the Terminal command

$ brew install geckodriver

Because homebrew already did extend the PATH there's no need to modify any startup scripts.

I want to remove double quotes from a String

If you want to remove all double quotes in string, use

var str = '"some "quoted" string"';
console.log( str.replace(/"/g, '') );
// some quoted string

Otherwise you want to remove only quotes around the string, use:

var str = '"some "quoted" string"';
console.log( clean = str.replace(/^"|"$/g, '') );
// some "quoted" string

How to change the default browser to debug with in Visual Studio 2008?

If you are using MVC 2 you do not need to create another project, just add component -> webform to the project then:

* Right click the webform  
* Select Browse With...  
* Choose your browser  
* Click Set as Default  
* Delete the webform

Image inside div has extra space below the image

I used line-height:0 and it works fine for me.

Single statement across multiple lines in VB.NET without the underscore character

No, the underscore is the only continuation character. Personally I prefer the occasional use of a continuation character to being forced to use it always as in C#, but apart from the comments issue (which I'd agree is sometimes annoying), getting things to line up is not an issue.

With VS2008 at any rate, just select the second and following lines, hit the tab key several times, and it moves the whole lot across.

If it goes a tiny bit too far, you can delete the excess space a character at a time. It's a little fiddly, but it stays put once it's saved.

On the rare cases where this isn't good enough, I sometimes use the following technique to get it all to line up:

dim results as String = ""
results += "from a in articles "
results += "where a.articleID = 4 " 'and now you can add comments
results += "select a.articleName"

It's not perfect, and I know those that prefer C# will be tut-tutting, but there it is. It's a style choice, but I still prefer it to endless semi-colons.

Now I'm just waiting for someone to tell me I should have used a StringBuilder ;-)

Is Python strongly typed?

According to this wiki Python article Python is both dynamically and strongly typed (provides a good explanation too).

Perhaps you are thinking about statically typed languages where types can not change during program execution and type checking occurs during compile time to detect possible errors.

This SO question might be of interest: Dynamic type languages versus static type languages and this Wikipedia article on Type Systems provides more information

Setting the zoom level for a MKMapView

Based on @AdilSoomro's great answer. I have come up with this:

@interface MKMapView (ZoomLevel)
- (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate

-(double) getZoomLevel;

@implementation MKMapView (ZoomLevel)

- (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate
                  zoomLevel:(NSUInteger)zoomLevel animated:(BOOL)animated {
    MKCoordinateSpan span = MKCoordinateSpanMake(0, 360/pow(2, zoomLevel)*self.frame.size.width/256);
    [self setRegion:MKCoordinateRegionMake(centerCoordinate, span) animated:animated];

-(double) getZoomLevel {
    return log2(360 * ((self.frame.size.width/256) / self.region.span.longitudeDelta));


datatable jquery - table header width not aligned with body width

issue is data table is called before the data table is drawn on DOM,use set time out before calling data table.

    var table = $('#exampleSummary').removeAttr('width').DataTable( {
        scrollY:        "300px",
        scrollX:        true,
        scrollCollapse: true,
        paging:         true,
        columnDefs: [
            { width: 200, targets: 0 }
        fixedColumns: false
    } );
}, 100);


HEAD is (direct or indirect, i.e. symbolic) reference to the current commit. It is a commit that you have checked in the working directory (unless you made some changes, or equivalent), and it is a commit on top of which "git commit" would make a new one. Usually HEAD is symbolic reference to some other named branch; this branch is currently checked out branch, or current branch. HEAD can also point directly to a commit; this state is called "detached HEAD", and can be understood as being on unnamed, anonymous branch.

And @ alone is a shortcut for HEAD, since Git 1.8.5

ORIG_HEAD is previous state of HEAD, set by commands that have possibly dangerous behavior, to be easy to revert them. It is less useful now that Git has reflog: HEAD@{1} is roughly equivalent to ORIG_HEAD (HEAD@{1} is always last value of HEAD, ORIG_HEAD is last value of HEAD before dangerous operation).

For more information read git(1) manpage / [gitrevisions(7) manpage][git-revisions], Git User's Manual, the Git Community Book and Git Glossary

How to catch exception output from Python subprocess.check_output()?

There are good answers here, but in these answers, there has not been an answer that comes up with the text from the stack-trace output, which is the default behavior of an exception.

If you wish to use that formatted traceback information, you might wish to:

import traceback

    check_call( args )
except CalledProcessError:
    tb = traceback.format_exc()
    tb = tb.replace(passwd, "******")

As you might be able to tell, the above is useful in case you have a password in the check_call( args ) that you wish to prevent from displaying.

Make header and footer files to be included in multiple html pages

Save the HTML you want to include in an .html file:


<a href="howto_google_maps.asp">Google Maps</a><br>
<a href="howto_css_animate_buttons.asp">Animated Buttons</a><br>
<a href="howto_css_modals.asp">Modal Boxes</a><br>
<a href="howto_js_animate.asp">Animations</a><br>
<a href="howto_js_progressbar.asp">Progress Bars</a><br>
<a href="howto_css_dropdown.asp">Hover Dropdowns</a><br>
<a href="howto_js_dropdown.asp">Click Dropdowns</a><br>
<a href="howto_css_table_responsive.asp">Responsive Tables</a><br>

Include the HTML

Including HTML is done by using a w3-include-html attribute:


    <div w3-include-html="content.html"></div>

Add the JavaScript

HTML includes are done by JavaScript.

    function includeHTML() {
      var z, i, elmnt, file, xhttp;
      /*loop through a collection of all HTML elements:*/
      z = document.getElementsByTagName("*");
      for (i = 0; i < z.length; i++) {
        elmnt = z[i];
        /*search for elements with a certain atrribute:*/
        file = elmnt.getAttribute("w3-include-html");
        if (file) {
          /*make an HTTP request using the attribute value as the file name:*/
          xhttp = new XMLHttpRequest();
          xhttp.onreadystatechange = function() {
            if (this.readyState == 4) {
              if (this.status == 200) {elmnt.innerHTML = this.responseText;}
              if (this.status == 404) {elmnt.innerHTML = "Page not found.";}
              /*remove the attribute, and call this function once more:*/
"GET", file, true);
          /*exit the function:*/

Call includeHTML() at the bottom of the page:


<!DOCTYPE html>
function includeHTML() {
  var z, i, elmnt, file, xhttp;
  /*loop through a collection of all HTML elements:*/
  z = document.getElementsByTagName("*");
  for (i = 0; i < z.length; i++) {
    elmnt = z[i];
    /*search for elements with a certain atrribute:*/
    file = elmnt.getAttribute("w3-include-html");
    if (file) {
      /*make an HTTP request using the attribute value as the file name:*/
      xhttp = new XMLHttpRequest();
      xhttp.onreadystatechange = function() {
        if (this.readyState == 4) {
          if (this.status == 200) {elmnt.innerHTML = this.responseText;}
          if (this.status == 404) {elmnt.innerHTML = "Page not found.";}
          /*remove the attribute, and call this function once more:*/
      }   "GET", file, true);
      /*exit the function:*/

<div w3-include-html="h1.html"></div> 
<div w3-include-html="content.html"></div> 



Bootstrap 3: Text overlay on image

Is this what you're after?

I added :text-align:center to the div and image

What is the maximum characters for the NVARCHAR(MAX)?

By default, nvarchar(MAX) values are stored exactly the same as nvarchar(4000) values would be, unless the actual length exceed 4000 characters; in that case, the in-row data is replaced by a pointer to one or more seperate pages where the data is stored.

If you anticipate data possibly exceeding 4000 character, nvarchar(MAX) is definitely the recommended choice.


A keyboard shortcut to comment/uncomment the select text in Android Studio

On Mac you need cmd + / to comment and uncomment.

Write to custom log file from a Bash script

@chepner make a good point that logger is dedicated to logging messages.

I do need to mention that @Thomas Haratyk simply inquired why I didn't simply use echo.

At the time, I didn't know about echo, as I'm learning shell-scripting, but he was right.

My simple solution is now this:

echo "This logs to where I want, but using echo" > /var/log/mycustomlog

The example above will overwrite the file after the >

So, I can append to that file with this:

echo "I will just append to my custom log file" >> /var/log/customlog

Thanks guys!

  • on a side note, it's simply my personal preference to keep my personal logs in /var/log/, but I'm sure there are other good ideas out there. And since I didn't create a daemon, /var/log/ probably isn't the best place for my custom log file. (just saying)

A simple command line to download a remote maven2 artifact to the local repository?

Since version 2.1 of the Maven Dependency Plugin, there is a dependency:get goal for this purpose. To make sure you are using the right version of the plugin, you'll need to use the "fully qualified name":

mvn org.apache.maven.plugins:maven-dependency-plugin:2.1:get \
    -DrepoUrl= \

Delete all lines starting with # or ; in Notepad++

Its possible, but not directly.

In short, go to the search, use your regex, check "mark line" and click "Find all". It results in bookmarks for all those lines.

In the search menu there is a point "delete bookmarked lines" voila.

I found the answer here (the correct answer is the second one, not the accepted!): How to delete specific lines on Notepad++?

Use a.any() or a.all()

If you take a look at the result of valeur <= 0.6, you can see what’s causing this ambiguity:

>>> valeur <= 0.6
array([ True, False, False, False], dtype=bool)

So the result is another array that has in this case 4 boolean values. Now what should the result be? Should the condition be true when one value is true? Should the condition be true only when all values are true?

That’s exactly what numpy.any and numpy.all do. The former requires at least one true value, the latter requires that all values are true:

>>> np.any(valeur <= 0.6)
>>> np.all(valeur <= 0.6)

Setting unique Constraint with fluent API?

modelBuilder.Property(x => x.FirstName).IsUnicode().IsRequired().HasMaxLength(50);

Composer require runs out of memory. PHP Fatal error: Allowed memory size of 1610612736 bytes exhausted

I am using php7.2 and the size is set to memory_limit = 512M by default. to increase the size, you need to locate php.ini.

In Wamp, it is located in C:\wamp64\bin\php\php7.2.23\php.ini. Please watch out for the PHP version as it is the name folder, in my case I have php7.2.23

In Laragon, it is located in C:\laragon\bin\php\php-7.2.23-Win32-VC15-x64\php.ini as was in my case.

If you don't want to allow unlimited space, you can set whatever size that is convenient to you, in my case I did memory_limit = 2G

if you want to allow unlimited space, you can change to memory_limit = -1

How to replace multiple white spaces with one white space

Using the test program that Jon Skeet posted, I tried to see if I could get a hand written loop to run faster.
I can beat NormalizeWithSplitAndJoin every time, but only beat NormalizeWithRegex with inputs of 1000, 5.

static string NormalizeWithLoop(string input)
    StringBuilder output = new StringBuilder(input.Length);

    char lastChar = '*';  // anything other then space 
    for (int i = 0; i < input.Length; i++)
        char thisChar = input[i];
        if (!(lastChar == ' ' && thisChar == ' '))

        lastChar = thisChar;

    return output.ToString();

I have not looked at the machine code the jitter produces, however I expect the problem is the time taken by the call to StringBuilder.Append() and to do much better would need the use of unsafe code.

So Regex.Replace() is very fast and hard to beat!!

How to set the height of an input (text) field in CSS?

The best way to do this is:

  padding: 20px 10px;
  line-height: 28px;

Url.Action parameters?

This works for MVC 5:

<a href="@Url.Action("ActionName", "ControllerName", new { paramName1 = item.paramValue1, paramName2 = item.paramValue2 })" >
    Link text

How can I convert a Unix timestamp to DateTime and vice versa?

Here's what you need:

public static DateTime UnixTimeStampToDateTime( double unixTimeStamp )
    // Unix timestamp is seconds past epoch
    System.DateTime dtDateTime = new DateTime(1970,1,1,0,0,0,0,System.DateTimeKind.Utc);
    dtDateTime = dtDateTime.AddSeconds( unixTimeStamp ).ToLocalTime();
    return dtDateTime;

Or, for Java (which is different because the timestamp is in milliseconds, not seconds):

public static DateTime JavaTimeStampToDateTime( double javaTimeStamp )
    // Java timestamp is milliseconds past epoch
    System.DateTime dtDateTime = new DateTime(1970,1,1,0,0,0,0,System.DateTimeKind.Utc);
    dtDateTime = dtDateTime.AddMilliseconds( javaTimeStamp ).ToLocalTime();
    return dtDateTime;

How to Create an excel dropdown list that displays text with a numeric hidden value

There are two types of drop down lists available (I am not sure since which version).

ActiveX Drop Down
You can set the column widths, so your hidden column can be set to 0.

Form Drop Down
You could set the drop down range to a hidden sheet and reference the cell adjacent to the selected item. This would also work with the ActiveX type control.

Split a string by a delimiter in python

You may be interested in the csv module, which is designed for comma-separated files but can be easily modified to use a custom delimiter.

import csv
csv.register_dialect( "myDialect", delimiter = "__", <other-options> )
lines = [ "MATCHES__STRING" ]

for row in csv.reader( lines ):

UIView with rounded corners and drop shadow?

This worked for me. Trick was to move the background color from the main view to the layer.

CALayer *layer = view.layer;
layer.cornerRadius = 15.0f;
layer.masksToBounds = NO;

layer.shadowOffset = CGSizeMake(0, 3);
layer.shadowColor = [[UIColor blackColor] CGColor];
layer.shadowRadius = 2.0f;
layer.shadowOpacity = 0.35f;
layer.shadowPath = [[UIBezierPath bezierPathWithRoundedRect:layer.bounds cornerRadius:layer.cornerRadius] CGPath];

CGColorRef  bColor = view.backgroundColor.CGColor;
view.backgroundColor = nil;
layer.backgroundColor =  bColor ;

Where can I find the assembly System.Web.Extensions dll?

Your project is mostly likely targetting .NET Framework 4 Client Profile. Check the application tab in your project properties.

This question has a good answer on the different versions: Target framework, what does ".NET Framework ... Client Profile" mean?

Is there a C# case insensitive equals operator?

Others answer are totally valid here, but somehow it takes some time to type StringComparison.OrdinalIgnoreCase and also using String.Compare.

I've coded simple String extension method, where you could specify if comparison is case sensitive or case senseless with boolean - see following answer:

Convert HashBytes to VarChar

Changing the datatype to varbinary seems to work the best for me.

How can I get the content of CKEditor using JQuery?

Using Pure Vanilla Javascript / Jquery or in any javascript library :

If you have Ckeditor loaded in below text-area:

 <textarea name="editor1" id="editor1"></textarea>

Then you can get content inside textarea as below:

var txtNotes = document.getElementsByClassName('ck-content')[0].innerHTML;

Column order manipulation using col-lg-push and col-lg-pull in Twitter Bootstrap 3

Pull "pulls" the div towards the left of the browser and and Push "pushes" the div away from left of browser.

Like: enter image description here

So basically in a 3 column layout of any web page the "Main Body" appears at the "Center" and in "Mobile" view the "Main Body" appears at the "Top" of the page. This is mostly desired by everyone with 3 column layout.

<div class="container">
    <div class="row">
        <div id="content" class="col-lg-4 col-lg-push-4 col-sm-12">
        <h2>This is Content</h2>
        <p>orem Ipsum ...</p>

        <div id="sidebar-left" class="col-lg-4  col-sm-6 col-lg-pull-4">
        <h2>This is Left Sidebar</h2>
        <p>orem Ipsum...</p>

        <div id="sidebar-right" class="col-lg-4 col-sm-6">
        <h2>This is Right Sidebar</h2>
        <p>orem Ipsum.... </p>

You can view it here:

Hope it helps

How to add 20 minutes to a current date?

you have a lot of answers in the post

var d1 = new Date (),
d2 = new Date ( d1 );
d2.setMinutes ( d1.getMinutes() + 20 );
alert ( d2 );

Android draw a Horizontal line between views

Try this works for me

 <View android:layout_width="1dp"
       android:background="@color/tw_composer" />

Is it better practice to use String.format over string Concatenation in Java?

Here's a test with multiple sample sizes in milliseconds.

public class Time {

public static String sysFile = "/sys/class/camera/rear/rear_flash";
public static String cmdString = "echo %s > " + sysFile;

public static void main(String[] args) {

  int i = 1;
  for(int run=1; run <= 12; run++){
      for(int test =1; test <= 2 ; test++){
                String.format("\nTEST: %s, RUN: %s, Iterations: %s",run,test,i));
        test(run, i);
      i = i*3;

public static void test(int run, int iterations){

      long start = System.nanoTime();
      for( int i=0;i<iterations; i++){
          String s = "echo " + i + " > "+ sysFile;
      long t = System.nanoTime() - start;   
      String r = String.format("  %-13s =%10d %s", "Concatenation",t,"nanosecond");
      System.out.println(r) ;

     start = System.nanoTime();       
     for( int i=0;i<iterations; i++){
         String s =  String.format(cmdString, i);
     t = System.nanoTime() - start; 
     r = String.format("  %-13s =%10d %s", "Format",t,"nanosecond");

      start = System.nanoTime();          
      for( int i=0;i<iterations; i++){
          StringBuilder b = new StringBuilder("echo ");
          b.append(i).append(" > ").append(sysFile);
          String s = b.toString();
     t = System.nanoTime() - start; 
     r = String.format("  %-13s =%10d %s", "StringBuilder",t,"nanosecond");


TEST: 1, RUN: 1, Iterations: 1
  Concatenation =     14911 nanosecond
  Format        =     45026 nanosecond
  StringBuilder =      3509 nanosecond

TEST: 1, RUN: 2, Iterations: 1
  Concatenation =      3509 nanosecond
  Format        =     38594 nanosecond
  StringBuilder =      3509 nanosecond


TEST: 2, RUN: 1, Iterations: 3
  Concatenation =      8479 nanosecond
  Format        =     94438 nanosecond
  StringBuilder =      5263 nanosecond

TEST: 2, RUN: 2, Iterations: 3
  Concatenation =      4970 nanosecond
  Format        =     92976 nanosecond
  StringBuilder =      5848 nanosecond


TEST: 3, RUN: 1, Iterations: 9
  Concatenation =     11403 nanosecond
  Format        =    287115 nanosecond
  StringBuilder =     14326 nanosecond

TEST: 3, RUN: 2, Iterations: 9
  Concatenation =     12280 nanosecond
  Format        =    209051 nanosecond
  StringBuilder =     11818 nanosecond


TEST: 5, RUN: 1, Iterations: 81
  Concatenation =     54383 nanosecond
  Format        =   1503113 nanosecond
  StringBuilder =     40056 nanosecond

TEST: 5, RUN: 2, Iterations: 81
  Concatenation =     44149 nanosecond
  Format        =   1264241 nanosecond
  StringBuilder =     34208 nanosecond


TEST: 6, RUN: 1, Iterations: 243
  Concatenation =     76018 nanosecond
  Format        =   3210891 nanosecond
  StringBuilder =     76603 nanosecond

TEST: 6, RUN: 2, Iterations: 243
  Concatenation =     91222 nanosecond
  Format        =   2716773 nanosecond
  StringBuilder =     73972 nanosecond


TEST: 8, RUN: 1, Iterations: 2187
  Concatenation =    527450 nanosecond
  Format        =  10291108 nanosecond
  StringBuilder =    885027 nanosecond

TEST: 8, RUN: 2, Iterations: 2187
  Concatenation =    526865 nanosecond
  Format        =   6294307 nanosecond
  StringBuilder =    591773 nanosecond


TEST: 10, RUN: 1, Iterations: 19683
  Concatenation =   4592961 nanosecond
  Format        =  60114307 nanosecond
  StringBuilder =   2129387 nanosecond

TEST: 10, RUN: 2, Iterations: 19683
  Concatenation =   1850166 nanosecond
  Format        =  35940524 nanosecond
  StringBuilder =   1885544 nanosecond


TEST: 12, RUN: 1, Iterations: 177147
  Concatenation =  26847286 nanosecond
  Format        = 126332877 nanosecond
  StringBuilder =  17578914 nanosecond

TEST: 12, RUN: 2, Iterations: 177147
  Concatenation =  24405056 nanosecond
  Format        = 129707207 nanosecond
  StringBuilder =  12253840 nanosecond

Android: Is it possible to display video thumbnails?

I really suggest you to use the Glide library. It's among the most efficient way to generate and display a video thumbnail for a local video file.

Just add this line to your gradle file :

compile 'com.github.bumptech.glide:glide:3.7.0'

And it will become as simple as :

String filePath = "/storage/emulated/0/Pictures/example_video.mp4";

    .with( context )
    .load( Uri.fromFile( new File( filePath ) ) )
    .into( imageViewGifAsBitmap );

You can find more informations here :

Cheers !

'module' object has no attribute 'DataFrame'

Change the file name if your file name is like or, it will shadow the real name otherwise.

jQuery limit to 2 decimal places

Here is a working example in both Javascript and jQuery:

//In jQuery
$("#calculate").click(function() {
    var num = parseFloat($("#textbox").val());
    var new_num = $("#textbox").val(num.toFixed(2));

// In javascript
document.getElementById('calculate').onclick = function() {
    var num = parseFloat(document.getElementById('textbox').value);
    var new_num = num.toFixed(2);
    document.getElementById('textbox').value = new_num;

How do I get the "id" after INSERT into MySQL database with Python?



SELECT last_insert_id();

How to run Python script on terminal?

First of all, you need to move to the location of the file you are trying to execute, so in a Terminal:

cd ~/Documents/python

Now, you should be able to execute your file:


duplicate 'row.names' are not allowed error

This related question points out a part of the ?read.table documentation that explains your problem:

If there is a header and the first row contains one fewer field than the number of columns, the first column in the input is used for the row names. Otherwise if row.names is missing, the rows are numbered.

Your header row likely has 1 fewer column than the rest of the file and so read.table assumes that the first column is the row.names (which must all be unique), not a column (which can contain duplicated values). You can fix this by using one of the following two Solutions:

  1. adding a delimiter (ie \t or ,) to the front or end of your header row in the source file, or,
  2. removing any trailing delimiters in your data

The choice will depend on the structure of your data.

Here the header row is interpreted as having one fewer column than the data because the delimiters don't match:

v1,v2,v3   # 3 items!!
a1,a2,a3,  # 4 items
b1,b2,b3,  # 4 items

This is how it is interpreted by default:

   v1,v2,v3   # 3 items!!
a1,a2,a3,  # 4 items
b1,b2,b3,  # 4 items

The first column (with no header) values are interpreted as row.names: a1 and b1. If this column contains duplicates, which is entirely possible, then you get the duplicate 'row.names' are not allowed error.

If you set row.names = FALSE, the shift doesn't happen, but you still have a mismatching number of items in the header and in the data because the delimiters don't match.

Solution 1 Add trailing delimiter to header:

v1,v2,v3,  # 4 items!!
a1,a2,a3,  # 4 items
b1,b2,b3,  # 4 items

Solution 2 Remove excess trailing delimiter from non-header rows:

v1,v2,v3   # 3 items
a1,a2,a3   # 3 items!!
b1,b2,b3   # 3 items!!

Case Statement Equivalent in R

Imho, most straightforward and universal code:

dft=data.frame(x = sample(letters[1:8], 20, replace=TRUE))
    y[x %in% c('a','b','c')]='abc'
    y[x %in% c('d','e','f')]='def'
    y[x %in% 'g']='g'
    y[x %in% 'h']='h'

How Connect to remote host from Aptana Studio 3

There's also an option to Auto Sync built-in in Aptana.

step 1

step 2

Doctrine - How to print out the real sql, not just the prepared statement?

getSqlQuery() does technically show the whole SQL command, but it's a lot more useful when you can see the parameters as well.

echo $q->getSqlQuery();
foreach ($q->getFlattenedParams() as $index => $param)
  echo "$index => $param";

To make this pattern more reusable, there's a nice approach described in the comments at Raw SQL from Doctrine Query Object.

How to add an extra language input to Android?

Don't agree with post above. I have a Hero with only English available and I want Spanish.

I installed MoreLocale 2, and it has lots of different languages (Dutch among them). I choose Spanish, Sense UI restarted and EVERYTHING in my phone changed to Spanish: menus, settings, etc. The keyboard predictive text defaulted to Spanish and started suggesting words in Spanish. This means, somewhere within the OS there is a Spanish dictionary hidden and MoreLocale made it available.

The problem is that English is still the only option available in keyboard input language so I can switch to English but can't switch back to Spanish unless I restart Sense UI, which takes a couple of minutes so not a very practical solution.

Still looking for an easier way to do it so please help.

How to create a SQL Server function to "join" multiple rows from a subquery into a single delimited field?

From what I can see FOR XML (as posted earlier) is the only way to do it if you want to also select other columns (which I'd guess most would) as the OP does. Using COALESCE(@var... does not allow inclusion of other columns.

Update: Thanks to there is a way to remove the "trailing" comma to. By making it into a leading comma and using the STUFF function of MSSQL you can replace the first character (leading comma) with an empty string as below:

    (select ',' + Column 
     from Table
         inner where inner.Id = outer.Id 
     for xml path('')
), 1,1,'') as Values

Javascript to stop HTML5 video playback on modal window close

Try this:

    $("#showSimpleModal").click(function() {
        return false;   

    $("#closeSimple").click(function() {
        return false;                   

How to monitor the memory usage of Node.js?

node-memwatch : detect and find memory leaks in Node.JS code. Check this tutorial Tracking Down Memory Leaks in Node.js

What's the @ in front of a string in C#?

An '@' has another meaning as well: putting it in front of a variable declaration allows you to use reserved keywords as variable names.

For example:

string @class = "something";
int @object = 1;

I've only found one or two legitimate uses for this. Mainly in ASP.NET MVC when you want to do something like this:

<%= Html.ActionLink("Text", "Action", "Controller", null, new { @class = "some_css_class" })%>

Which would produce an HTML link like:

<a href="/Controller/Action" class="some_css_class">Text</a>

Otherwise you would have to use 'Class', which isn't a reserved keyword but the uppercase 'C' does not follow HTML standards and just doesn't look right.

Best practices when running Node.js with port 80 (Ubuntu / Linode)

Port 80

What I do on my cloud instances is I redirect port 80 to port 3000 with this command:

sudo iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 3000

Then I launch my Node.js on port 3000. Requests to port 80 will get mapped to port 3000.

You should also edit your /etc/rc.local file and add that line minus the sudo. That will add the redirect when the machine boots up. You don't need sudo in /etc/rc.local because the commands there are run as root when the system boots.


Use the forever module to launch your Node.js with. It will make sure that it restarts if it ever crashes and it will redirect console logs to a file.

Launch on Boot

Add your Node.js start script to the file you edited for port redirection, /etc/rc.local. That will run your Node.js launch script when the system starts.

Digital Ocean & other VPS

This not only applies to Linode, but Digital Ocean, AWS EC2 and other VPS providers as well. However, on RedHat based systems /etc/rc.local is /ect/rc.d/local.

XML Parsing - Read a Simple XML File and Retrieve Values

Try XmlSerialization

try this

public class Task
    public string Name{get; set;}
    public string Location {get; set;}
    public string Arguments {get; set;}
    public DateTime RunWhen {get; set;}

public void WriteXMl(Task task)
    XmlSerializer serializer;
    serializer = new XmlSerializer(typeof(Task));

    MemoryStream stream = new MemoryStream();

    StreamWriter writer = new StreamWriter(stream, Encoding.Unicode);
    serializer.Serialize(writer, task);

    int count = (int)stream.Length;

     byte[] arr = new byte[count];
     stream.Seek(0, SeekOrigin.Begin);

     stream.Read(arr, 0, count);

     using (BinaryWriter binWriter=new BinaryWriter(File.Open(@"C:\Temp\Task.xml", FileMode.Create)))

 public Task GetTask()
     StreamReader stream = new StreamReader(@"C:\Temp\Task.xml", Encoding.Unicode);
     return (Task)serializer.Deserialize(stream);

How to read a text file from server using JavaScript?

You need to use Ajax, which is basically sending a request to the server, then getting a JSON object, which you convert to a JavaScript object.

Check this:

If you are using jQuery library, it can be even easier:

Having said this, I highly recommend you don't download a file of 3.5MB into JS! It is not a good idea. Do the processing on your server, then return the data after processing. Then if you want to get a new data, send a new Ajax request, process the request on server, then return the new data.

Hope that helps.

TextView Marquee not working

Working Code:

    android:text="Some veryyyyy long text with all the characters that cannot fit in screen, it so sad :( that I will not scroll"
    android:textAppearance="?android:attr/textAppearanceLarge" />

Executing <script> injected by innerHTML after AJAX call

I used this code, it is working fine

var arr = MyDiv.getElementsByTagName('script')
for (var n = 0; n < arr.length; n++)
    eval(arr[n].innerHTML)//run script inside div

How do I list all cron jobs for all users?

Since it is a matter of looping through a file (/etc/passwd) and performing an action, I am missing the proper approach on How can I read a file (data stream, variable) line-by-line (and/or field-by-field)?:

while IFS=":" read -r user _
   echo "crontab for user ${user}:"
   crontab -u "$user" -l
done < /etc/passwd

This reads /etc/passwd line by line using : as field delimiter. By saying read -r user _, we make $user hold the first field and _ the rest (it is just a junk variable to ignore fields).

This way, we can then call crontab -u using the variable $user, which we quote for safety (what if it contains spaces? It is unlikely in such file, but you can never know).

Submitting a form on 'Enter' with jQuery?

Just adding for easy implementation. You can simply make a form and then make the submit button hidden:

For example:

<form action="submit.php" method="post">
Name : <input type="text" name="test">
<input type="submit" style="display: none;">

Count number of times value appears in particular column in MySQL

Take a look at the Group by function.

What the group by function does is pretuty much grouping the similar value for a given field. You can then show the number of number of time that this value was groupped using the COUNT function.

MySQL Documentation

You can also use the group by function with a good number of other function define by MySQL (see the above link).

mysql> SELECT student_name, AVG(test_score)
    ->        FROM student
    ->        GROUP BY student_name;

Adding an arbitrary line to a matplotlib plot in ipython notebook

Rather than abusing plot or annotate, which will be inefficient for many lines, you can use matplotlib.collections.LineCollection:

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.collections import LineCollection

x = np.arange(1, 101)
y = 20 + 3 * x + np.random.normal(0, 60, 100)
plt.plot(x, y, "o")

# Takes list of lines, where each line is a sequence of coordinates
l1 = [(70, 100), (70, 250)]
l2 = [(70, 90), (90, 200)]
lc = LineCollection([l1, l2], color=["k","blue"], lw=2)


Figure with two lines plotted via LineCollection

It takes a list of lines [l1, l2, ...], where each line is a sequence of N coordinates (N can be more than two).

The standard formatting keywords are available, accepting either a single value, in which case the value applies to every line, or a sequence of M values, in which case the value for the ith line is values[i % M].

Read and Write CSV files including unicode with Python 2.7

Another alternative:

Use the code from the unicodecsv package ...

>>> import unicodecsv as csv
>>> from io import BytesIO
>>> f = BytesIO()
>>> w = csv.writer(f, encoding='utf-8')
>>> _ = w.writerow((u'é', u'ñ'))
>>> _ =
>>> r = csv.reader(f, encoding='utf-8')
>>> next(r) == [u'é', u'ñ']

This module is API compatible with the STDLIB csv module.

Escaping ampersand character in SQL string

REPLACE(<your xml column>,'&',chr(38)||'amp;')

Copy entire directory contents to another directory?

With regard to Java, there is no such method in the standard API. In Java 7, the java.nio.file.Files class will provide a copy convenience method.


  1. The Java Tutorials

  2. Copying files from one directory to another in Java

Convert int to string?

string a = i.ToString();
string b = Convert.ToString(i);
string c = string.Format("{0}", i);
string d = $"{i}";
string e = "" + i;
string f = string.Empty + i;
string g = new StringBuilder().Append(i).ToString();

Clearing Magento Log Data

Login to your c-panel goto phpmyadmin using SQL run below query to clear logs

TRUNCATE dataflow_batch_export;
TRUNCATE dataflow_batch_import;
TRUNCATE log_customer;
TRUNCATE log_quote;
TRUNCATE log_summary;
TRUNCATE log_summary_type;
TRUNCATE log_url;
TRUNCATE log_url_info;
TRUNCATE log_visitor;
TRUNCATE log_visitor_info;
TRUNCATE log_visitor_online;
TRUNCATE report_viewed_product_index;
TRUNCATE report_compared_product_index;
TRUNCATE report_event;
TRUNCATE index_event;

How to checkout a specific Subversion revision from the command line?

You'll have to use svn directly:

svn checkout URL[@REV]... [PATH]


svn help co

gives you a little more help.

How to write UTF-8 in a CSV file

For python2 you can use this code before csv_writer.writerows(rows)
This code will NOT convert integers to utf-8 strings

def encode_rows_to_utf8(rows):
    encoded_rows = []
    for row in rows:
        encoded_row = []
        for value in row:
            if isinstance(value, basestring):
                value = unicode(value).encode("utf-8")
    return encoded_rows

How to get a variable value if variable name is stored as string?

For my fellow zsh users, the way to accomplish the same thing as the accepted answer is to use:


It is appropriately called Parameter name replacement

This forces the value of the parameter name to be interpreted as a further parameter name, whose value will be used where appropriate. Note that flags set with one of the typeset family of commands (in particular case transformations) are not applied to the value of name used in this fashion.

If used with a nested parameter or command substitution, the result of that will be taken as a parameter name in the same way. For example, if you have ‘foo=bar’ and ‘bar=baz’, the strings ${(P)foo}, ${(P)${foo}}, and ${(P)$(echo bar)} will be expanded to ‘baz’.

Likewise, if the reference is itself nested, the expression with the flag is treated as if it were directly replaced by the parameter name. It is an error if this nested substitution produces an array with more than one word. For example, if ‘name=assoc’ where the parameter assoc is an associative array, then ‘${${(P)name}[elt]}’ refers to the element of the associative subscripted ‘elt’.

Data-frame Object has no Attribute

I'd like to make it simple for you. the reason of " 'DataFrame' object has no attribute 'Number'/'Close'/or any col name " is because you are looking at the col name and it seems to be "Number" but in reality it is " Number" or "Number " , that extra space is because in the excel sheet col name is written in that format. You can change it in excel or you can write data.columns = data.columns.str.strip() / df.columns = df.columns.str.strip() but the chances are that it will throw the same error in particular in some cases after the query. changing name in excel sheet will work definitely.

How to check if a double value has no decimal part

Compare two values: the normal double, and the double after flooring it. If they are the same value, there is no decimal component.

How can I reverse a list in Python?

There are 3 methods to get the reversed list:

  1. Slicing Method 1: reversed_array = array[-1::-1]

  2. Slicing Method 2: reversed_array2 = array[::-1]

  3. Using the builtin function: reversed_array = array.reverse()

The third function actually reversed the list object in place. That means no copy of pristine data is maintained. This is a good approach if you don't want to maintain the old version. But doesn't seem to be a solution if you do want the pristine and reversed version.

Get all inherited classes of an abstract class

typeof(AbstractDataExport).Assembly tells you an assembly your types are located in (assuming all are in the same).

assembly.GetTypes() gives you all types in that assembly or assembly.GetExportedTypes() gives you types that are public.

Iterating through the types and using type.IsAssignableFrom() gives you whether the type is derived.

What is the recommended way to delete a large number of items from DynamoDB?

According to the DynamoDB documentation you could just delete the full table.

See below:

"Deleting an entire table is significantly more efficient than removing items one-by-one, which essentially doubles the write throughput as you do as many delete operations as put operations"

If you wish to delete only a subset of your data, then you could make separate tables for each month, year or similar. This way you could remove "last month" and keep the rest of your data intact.

This is how you delete a table in Java using the AWS SDK:

DeleteTableRequest deleteTableRequest = new DeleteTableRequest()
DeleteTableResult result = client.deleteTable(deleteTableRequest);

Chrome doesn't delete session cookies

I just had this issue. I noticed that even after I closed my browser I had many Chrome processes running. Turns out these were each from my Chrome extension.

Under advanced settings I unchecked 'Continue running background apps when Google Chrome is closed' and my session cookies started working as they should.

Still a pain in the rear for all of us developers that have been coding expecting that session cookies would get cleared when the user is done browsing.

Cannot bulk load. Operating system error code 5 (Access is denied.)

  1. Go to start run=>services.msc=>SQL SERVER(MSSQLSERVER) stop the service
  2. Right click on SQL SERVER(MSSQLSERVER)=> properties=>LogOn Tab=>Local System Account=>OK
  3. Restart the SQL server Management Studio.

Python + Django page redirect

Depending on what you want (i.e. if you do not want to do any additional pre-processing), it is simpler to just use Django's redirect_to generic view:

from django.views.generic.simple import redirect_to

urlpatterns = patterns('',
    (r'^one/$', redirect_to, {'url': '/another/'}),


See documentation for more advanced examples.

For Django 1.3+ use:

from django.views.generic import RedirectView

urlpatterns = patterns('',
    (r'^one/$', RedirectView.as_view(url='/another/')),

Specified cast is not valid.. how to resolve this

If you are expecting double, decimal, float, integer why not use the one which accomodates all namely decimal (128 bits are enough for most numbers you are looking at).

instead of (double)value use decimal.Parse(value.ToString()) or Convert.ToDecimal(value)

Closing a file after File.Create


create write close

File.WriteAllBytes--   type binary


What do "branch", "tag" and "trunk" mean in Subversion repositories?

In addition to what Nick has said you can find out more at Streamed Lines: Branching Patterns for Parallel Software Development

enter image description here

In this figure main is the trunk, rel1-maint is a branch and 1.0 is a tag.

Changing tab bar item image and text color iOS

Subclass your TabbarViewController and in ViewDidLoad put this code:

 [UITabBarItem.appearance setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor darkGreyColorBT]} forState:UIControlStateNormal];
    [UITabBarItem.appearance setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor nightyDarkColorBT]} forState:UIControlStateSelected];

    self.tabBar.items[0].image  = [[UIImage imageNamed:@"ic-pack [email protected]"]  imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    self.tabBar.items[0].selectedImage  = [[UIImage imageNamed:@"[email protected]"]  imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    self.tabBar.items[1].image = [[UIImage imageNamed:@"ic-sleeptracker [email protected]"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    self.tabBar.items[1].selectedImage  = [[UIImage imageNamed:@"[email protected]"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    self.tabBar.items[2].image = [[UIImage imageNamed:@"ic-profile [email protected]"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    self.tabBar.items[2].selectedImage  = [[UIImage imageNamed:@"[email protected]"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

This is the simplest working solution I have

How to calculate the running time of my program?

Use System.currentTimeMillis() or System.nanoTime() if you want even more precise reading. Usually, milliseconds is precise enough if you need to output the value to the user. Moreover, System.nanoTime() may return negative values, thus it may be possible that, if you're using that method, the return value is not correct.

A general and wide use would be to use milliseconds :

long start = System.currentTimeMillis();


long end = System.currentTimeMillis();

NumberFormat formatter = new DecimalFormat("#0.00000");
System.out.print("Execution time is " + formatter.format((end - start) / 1000d) + " seconds");

Note that nanoseconds are usually used to calculate very short and precise program executions, such as unit testing and benchmarking. Thus, for overall program execution, milliseconds are preferable.

How to add headers to a multicolumn listbox in an Excel userform using VBA

I was looking at this problem just now and found this solution. If your RowSource points to a range of cells, the column headings in a multi-column listbox are taken from the cells immediately above the RowSource.

Using the example pictured here, inside the listbox, the words Symbol and Name appear as title headings. When I changed the word Name in cell AB1, then opened the form in the VBE again, the column headings changed.

Screenshot displaying a named range and the column headings outside the range.

The example came from a workbook in VBA For Modelers by S. Christian Albright, and I was trying to figure out how he got the column headings in his listbox :)

make arrayList.toArray() return more specific types

It doesn't really need to return Object[], for example:-

    List<Custom> list = new ArrayList<Custom>();
    list.add(new Custom(1));
    list.add(new Custom(2));

    Custom[] customs = new Custom[list.size()];

    for (Custom custom : customs) {

Here's my Custom class:-

public class Custom {
    private int i;

    public Custom(int i) {
        this.i = i;

    public String toString() {
        return String.valueOf(i);

Rownum in postgresql

If you just want a number to come back try this.

create temp sequence temp_seq;
SELECT inline_v1.ROWNUM,inline_v1.c1
select nextval('temp_seq') as ROWNUM, c1 
from sometable

You can add a order by to the inline_v1 SQL so your ROWNUM has some sequential meaning to your data.

select nextval('temp_seq') as ROWNUM, c1 
from sometable
ORDER BY c1 desc;

Might not be the fastest, but it's an option if you really do need them.

How to get the previous url using PHP

Use the $_SERVER['HTTP_REFERER'] header, but bear in mind anybody can spoof it at anytime regardless of whether they clicked on a link.

How do I solve this "Cannot read property 'appendChild' of null" error?

For all those facing a similar issue, I came across this same issue when i was trying to run a particular code snippet, shown below.

                var div, container = document.getElementById("container")
                for(var i=0;i<5;i++){
                    div = document.createElement("div");
                    div.onclick = function() { 
                        alert("This is a box #"+i);

        <div id="container"></div>

Looking at the error in the console for the above code.

Since the document.getElementById is returning a null and as null does not have a attribute named appendChild, therefore a error is thrown. To solve the issue see the code below.

            height: 200px;
            width: 700px;
            background-color: red;
            margin: 10px;

            height: 100px;
            width: 100px;
            background-color: purple;
            margin: 20px;
            display: inline-block;
        <div id="container"></div>
                var div, container = document.getElementById("container")
                for(let i=0;i<5;i++){
                    div = document.createElement("div");
                    div.onclick = function() { 
                        alert("This is a box #"+i);

I hope this helps. :)

How do you use window.postMessage across domains?

You should post a message from frame to parent, after loaded.

frame script:

$(document).ready(function() {
    window.parent.postMessage("I'm loaded", "*");

And listen it in parent:

function listenMessage(msg) {

if (window.addEventListener) {
    window.addEventListener("message", listenMessage, false);
} else {
    window.attachEvent("onmessage", listenMessage);

Use this link for more info:

Jupyter notebook not running code. Stuck on In [*]

Usually, stopping and restarting that particular cell fixes this issue.

What do all of Scala's symbolic operators mean?

Just adding to the other excellent answers. Scala offers two often criticized symbolic operators, /: (foldLeft) and :\ (foldRight) operators, the first being right-associative. So the following three statements are the equivalent:

( 1 to 100 ).foldLeft( 0, _+_ )
( 1 to 100 )./:( 0 )( _+_ )
( 0 /: ( 1 to 100 ) )( _+_ )

As are these three:

( 1 to 100 ).foldRight( 0, _+_ )
( 1 to 100 ).:\( 0 )( _+_ )
( ( 1 to 100 ) :\ 0 )( _+_ )

how to print an exception using logger?

Try to log the stack trace like below:

logger.error("Exception :: " , e);

Install gitk on Mac

I had the same issue. I installed gitx instead.

You can install gitx from here.

Download the package and install it. After that open the gitk from spotlight search, goto the top left corner. Click on GitX and enable the terminal usage.

Goto your repo and simply type:

$ gitx --all

It will open the Gui.

User manual:

Tesseract running error

I'm using Visual Studio 2017 Community Edition.
I solved this problem by making a directory called tessdata in the Debug directory of my project. Then I put the eng.traineddata file into said directory.

How to press/click the button using Selenium if the button does not have the Id?

In Selenium IDE you can do:

Command   |   clickAndWait
Target    |   //input[@value='Next' and @title='next']

It should work fine.

How do I list all remote branches in Git 1.7+?

Just run a git fetch command. It will pull all the remote branches to your local repository, and then do a git branch -a to list all the branches.

How can I get file extensions with JavaScript?

fetchFileExtention(fileName) {
    return fileName.slice((fileName.lastIndexOf(".") - 1 >>> 0) + 2);

Create a zip file and download it

One of the error could be that the file is not read as 'archive' format. check out ZipArchive not opening file - Error Code: 19. Open the downloaded file in text editor, if you have any html tags or debug statements at the starting, clear the buffer before reading the file.


How to create a WPF Window without a border that can be resized via a grip only?

While the accepted answer is very true, just want to point out that AllowTransparency has some downfalls. It does not allow child window controls to show up, ie WebBrowser, and it usually forces software rendering which can have negative performance effects.

There is a better work around though.

When you want to create a window with no border that is resizeable and is able to host a WebBrowser control or a Frame control pointed to a URL you simply couldn't, the contents of said control would show empty.

I found a workaround though; in the Window, if you set the WindowStyle to None, ResizeMode to NoResize (bear with me, you will still be able to resize once done) then make sure you have UNCHECKED AllowsTransparency you will have a static sized window with no border and will show the browser control.

Now, you probably still want to be able to resize right? Well we can to that with a interop call:

    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    private static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

    public static extern bool ReleaseCapture();

    //Attach this to the MouseDown event of your drag control to move the window in place of the title bar
    private void WindowDrag(object sender, MouseButtonEventArgs e) // MouseDown
        SendMessage(new WindowInteropHelper(this).Handle,
            0xA1, (IntPtr)0x2, (IntPtr)0);

    //Attach this to the PreviewMousLeftButtonDown event of the grip control in the lower right corner of the form to resize the window
    private void WindowResize(object sender, MouseButtonEventArgs e) //PreviewMousLeftButtonDown
        HwndSource hwndSource = PresentationSource.FromVisual((Visual)sender) as HwndSource;
        SendMessage(hwndSource.Handle, 0x112, (IntPtr)61448, IntPtr.Zero);

And voila, A WPF window with no border and still movable and resizable without losing compatibility with with controls like WebBrowser

Remove portion of a string after a certain character

You can use list and explode functions:

list($result) = explode("By", "Posted On April 6th By Some Dude", 2);
// $result is "Posted On April 6th "

CentOS: Enabling GD Support in PHP Installation

Put the command

yum install php-gd

and restart the server (httpd, nginx, etc)

service httpd restart

making matplotlib scatter plots from dataframes in Python's pandas

Try passing columns of the DataFrame directly to matplotlib, as in the examples below, instead of extracting them as numpy arrays.

df = pd.DataFrame(np.random.randn(10,2), columns=['col1','col2'])
df['col3'] = np.arange(len(df))**2 * 100 + 100

In [5]: df
       col1      col2  col3
0 -1.000075 -0.759910   100
1  0.510382  0.972615   200
2  1.872067 -0.731010   500
3  0.131612  1.075142  1000
4  1.497820  0.237024  1700

Vary scatter point size based on another column

plt.scatter(df.col1, df.col2, s=df.col3)
# OR (with pandas 0.13 and up)
df.plot(kind='scatter', x='col1', y='col2', s=df.col3)

enter image description here

Vary scatter point color based on another column

colors = np.where(df.col3 > 300, 'r', 'k')
plt.scatter(df.col1, df.col2, s=120, c=colors)
# OR (with pandas 0.13 and up)
df.plot(kind='scatter', x='col1', y='col2', s=120, c=colors)

enter image description here

Scatter plot with legend

However, the easiest way I've found to create a scatter plot with legend is to call plt.scatter once for each point type.

cond = df.col3 > 300
subset_a = df[cond].dropna()
subset_b = df[~cond].dropna()
plt.scatter(subset_a.col1, subset_a.col2, s=120, c='b', label='col3 > 300')
plt.scatter(subset_b.col1, subset_b.col2, s=60, c='r', label='col3 <= 300') 

enter image description here


From what I can tell, matplotlib simply skips points with NA x/y coordinates or NA style settings (e.g., color/size). To find points skipped due to NA, try the isnull method: df[df.col3.isnull()]

To split a list of points into many types, take a look at numpy select, which is a vectorized if-then-else implementation and accepts an optional default value. For example:

df['subset'] =[df.col3 < 150, df.col3 < 400, df.col3 < 600],
                         [0, 1, 2], -1)
for color, label in zip('bgrm', [0, 1, 2, -1]):
    subset = df[df.subset == label]
    plt.scatter(subset.col1, subset.col2, s=120, c=color, label=str(label))

enter image description here

PHP mPDF save file as PDF

This can be done like this. It worked fine for me. And also set the directory permissions to 777 or 775 if not set.

$mpdf->Output('directory_name/pdf_file_name.pdf', 'F');

Getting a slice of keys from a map

You also can take an array of keys with type []Value by method MapKeys of struct Value from package "reflect":

package main

import (

func main() {
    abc := map[string]int{
        "a": 1,
        "b": 2,
        "c": 3,

    keys := reflect.ValueOf(abc).MapKeys()

    fmt.Println(keys) // [a b c]

MySQl Error #1064

Sometimes when your table has a similar name to the database name you should use back tick. so instead of:

INSERT INTO, field2) VALUES ('value1', 'value2');

You should have this:

INSERT INTO `books`.`book`(`field1`, `field2`) VALUES ('value1', 'value2');

How do I print the key-value pairs of a dictionary in python

You can access your keys and/or values by calling items() on your dictionary.

for key, value in d.iteritems():
    print(key, value)

How to properly override clone method?

As much as the most of the answers here are valid, I need to tell that your solution is also how the actual Java API developers do it. (Either Josh Bloch or Neal Gafter)

Here is an extract from openJDK, ArrayList class:

public Object clone() {
    try {
        ArrayList<?> v = (ArrayList<?>) super.clone();
        v.elementData = Arrays.copyOf(elementData, size);
        v.modCount = 0;
        return v;
    } catch (CloneNotSupportedException e) {
        // this shouldn't happen, since we are Cloneable
        throw new InternalError(e);

As you have noticed and others mentioned, CloneNotSupportedException has almost no chance to be thrown if you declared that you implement the Cloneable interface.

Also, there is no need for you to override the method if you don't do anything new in the overridden method. You only need to override it when you need to do extra operations on the object or you need to make it public.

Ultimately, it is still best to avoid it and do it using some other way.

How are booleans formatted in Strings in Python?

To update this for Python-3 you can do this

"{} {}".format(True, False)

However if you want to actually format the string (e.g. add white space), you encounter Python casting the boolean into the underlying C value (i.e. an int), e.g.

>>> "{:<8} {}".format(True, False)
'1        False'

To get around this you can cast True as a string, e.g.

>>> "{:<8} {}".format(str(True), False)
'True     False'

How to change value of a request parameter in laravel

If you use custom requests for validation, for replace data for validation, or to set default data (for checkboxes or other) use override method prepareForValidation().

namespace App\Http\Requests\Admin\Category;
class CategoryRequest extends AbstractRequest
    protected function prepareForValidation()
        if ( ! $this->get('url')) {
                'url' => $this->get('name'),
            'url'    => \Str::slug($this->get('url')),
            'active' => (int)$this->get('active'),

I hope this information will be useful to somebody.

How can I exclude directories from grep -R?

If you are grepping for code in a git repository and node_modules is in your .gitignore, you can use git grep. git grep searches the tracked files in the working tree, ignoring everything from .gitignore

git grep "STUFF"

Java Compare Two List's object values?

String myData1 = list1.toString();
String myData2 = list2.toString()

return myData1.equals(myData2);

where :
list1 - List<MyData>
list2 - List<MyData>

Comparing the String worked for me. Also NOTE I had overridden toString() method in MyData class.

Best way to remove the last character from a string built with stringbuilder

Use the following after the loop.


or simply change to

string commaSeparatedList = input.Aggregate((a, x) => a + ", " + x)

How do I "un-revert" a reverted Git commit?

To get back the unstaged and staged changes which were reverted after a commit:

git reset HEAD@{1}

To recover all unstaged deletions:

git ls-files -d | xargs git checkout --

How to get annotations of a member variable?

If you need know if a annotation specific is present. You can do so:

    Field[] fieldList = obj.getClass().getDeclaredFields();

        boolean isAnnotationNotNull, isAnnotationSize, isAnnotationNotEmpty;

        for (Field field : fieldList) {

            //Return the boolean value
            isAnnotationNotNull = field.isAnnotationPresent(NotNull.class);
            isAnnotationSize = field.isAnnotationPresent(Size.class);
            isAnnotationNotEmpty = field.isAnnotationPresent(NotEmpty.class);


And so on for the other annotations...

I hope help someone.

Youtube - downloading a playlist - youtube-dl

Removing the v=...& part from the url, and only keep the list=... part. The main problem being the special character &, interpreted by the shell.

You can also quote your 'url' in your command.

More information here (for instance) :

How to make parent wait for all child processes to finish?

Use waitpid() like this:

pid_t childPid;  // the child process that the execution will soon run inside of. 
childPid = fork();

if(childPid == 0)  // fork succeeded 
   // Do something   

else if(childPid < 0)  // fork failed 
   // log the error

else  // Main (parent) process after fork succeeds 
    int returnStatus;    
    waitpid(childPid, &returnStatus, 0);  // Parent process waits here for child to terminate.

    if (returnStatus == 0)  // Verify child process terminated without error.  
       printf("The child process terminated normally.");    

    if (returnStatus == 1)      
       printf("The child process terminated with an error!.");    

Why .NET String is immutable?

Why are string types immutable in C#

String is a reference type, so it is never copied, but passed by reference. Compare this to the C++ std::string object (which is not immutable), which is passed by value. This means that if you want to use a String as a key in a Hashtable, you're fine in C++, because C++ will copy the string to store the key in the hashtable (actually std::hash_map, but still) for later comparison. So even if you later modify the std::string instance, you're fine. But in .Net, when you use a String in a Hashtable, it will store a reference to that instance. Now assume for a moment that strings aren't immutable, and see what happens: 1. Somebody inserts a value x with key "hello" into a Hashtable. 2. The Hashtable computes the hash value for the String, and places a reference to the string and the value x in the appropriate bucket. 3. The user modifies the String instance to be "bye". 4. Now somebody wants the value in the hashtable associated with "hello". It ends up looking in the correct bucket, but when comparing the strings it says "bye"!="hello", so no value is returned. 5. Maybe somebody wants the value "bye"? "bye" probably has a different hash, so the hashtable would look in a different bucket. No "bye" keys in that bucket, so our entry still isn't found.

Making strings immutable means that step 3 is impossible. If somebody modifies the string he's creating a new string object, leaving the old one alone. Which means the key in the hashtable is still "hello", and thus still correct.

So, probably among other things, immutable strings are a way to enable strings that are passed by reference to be used as keys in a hashtable or similar dictionary object.

Finding even or odd ID values

dividend % divisor

Dividend is the numeric expression to divide. Dividend must be any expression of integer data type in sql server.

Divisor is the numeric expression to divide the dividend. Divisor must be expression of integer data type except in sql server.

SELECT 15 % 2


Dividend = 15

Divisor = 2

Let's say you wanted to query

Query a list of CITY names from STATION with even ID numbers only.

Schema structure for STATION:

ID Number

CITY varchar

STATE varchar

select CITY from STATION as st where % 2 = 0

Will fetch the even set of records 

In order to fetch the odd records with Id as odd number.

select CITY from STATION as st where % 2 <> 0

% function reduces the value to either 0 or 1

What do two question marks together mean in C#?

coalescing operator

it's equivalent to

FormsAuth = formsAUth == null ? new FormsAuthenticationWrapper() : formsAuth

How to check if a value exists in an object using JavaScript

Use a loop:

for (let k in obj) {
    if (obj[k] === "test1") {
        return true;

Regular expression for letters, numbers and - _


This will also match for empty strings, if you do not want that exchange the last * for an +

How to convert decimal to hexadecimal in JavaScript

To sum it all up;

function toHex(i, pad) {

  if (typeof(pad) === 'undefined' || pad === null) {
    pad = 2;

  var strToParse = i.toString(16);

  while (strToParse.length < pad) {
    strToParse = "0" + strToParse;

  var finalVal =  parseInt(strToParse, 16);

  if ( finalVal < 0 ) {
    finalVal = 0xFFFFFFFF + finalVal + 1;

  return finalVal;

However, if you don't need to convert it back to an integer at the end (i.e. for colors), then just making sure the values aren't negative should suffice.

jQuery - Add ID instead of Class

$('selector').attr( 'id', 'yourId' );

Get an element by index in jQuery

You can use the eq method or selector:


How does C compute sin() and other math functions?

They are typically implemented in software and will not use the corresponding hardware (that is, aseembly) calls in most cases. However, as Jason pointed out, these are implementation specific.

Note that these software routines are not part of the compiler sources, but will rather be found in the correspoding library such as the clib, or glibc for the GNU compiler. See

If you want greater control, you should carefully evaluate what you need exactly. Some of the typical methods are interpolation of look-up tables, the assembly call (which is often slow), or other approximation schemes such as Newton-Raphson for square roots.

Resetting a setTimeout

clearTimeout() and feed the reference of the setTimeout, which will be a number. Then re-invoke it:

var initial;

function invocation() {
    initial = window.setTimeout( 
    function() { = 'black'
    }, 5000);


document.body.onclick = function() {
    clearTimeout( initial )
    // re-invoke invocation()

In this example, if you don't click on the body element in 5 seconds the background color will be black.


Note: setTimeout and clearTimeout are not ECMAScript native methods, but Javascript methods of the global window namespace.