Programs & Examples On #Occlusion culling

MySql Inner Join with WHERE clause

Yes you are right. You have placed WHERE clause wrong. You can only use one WHERE clause in single query so try AND for multiple conditions like this:

 SELECT table1.f_id  FROM table1 
   INNER JOIN table2
     ON table2.f_id = table1.f_id
 WHERE table2.f_type = 'InProcess'
   AND f_com_id = '430'
   AND f_status = 'Submitted' 

How to set layout_gravity programmatically?

I'd hate to be resurrecting old threads but this is a problem that is not answered correctly and moreover I've ran into this problem myself.

Here's the long bit, if you're only interested in the answer please scroll all the way down to the code:

android:gravity and android:layout_gravity works differently. Here's an article I've read that helped me.

GIST of article: gravity affects view after height/width is assigned. So gravity centre will not affect a view that is done FILL_PARENT (think of it as auto margin). layout_gravity centre WILL affect view that is FILL_PARENT (think of it as auto pad).

Basically, android:layout_gravity CANNOT be access programmatically, only android:gravity. In the OP's case and my case, the accepted answer does not place the button vertically centre.

To improve on Karthi's answer:

LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
params.gravity = Gravity.CENTER;

Link to LinearLayout.LayoutParams.

android:layout_gravity shows "No related methods" meaning cannot be access programatically. Whereas gravity is a field in the class.

What is object serialization?

You can think of serialization as the process of converting an object instance into a sequence of bytes (which may be binary or not depending on the implementation).

It is very useful when you want to transmit one object data across the network, for instance from one JVM to another.

In Java, the serialization mechanism is built into the platform, but you need to implement the Serializable interface to make an object serializable.

You can also prevent some data in your object from being serialized by marking the attribute as transient.

Finally you can override the default mechanism, and provide your own; this may be suitable in some special cases. To do this, you use one of the hidden features in java.

It is important to notice that what gets serialized is the "value" of the object, or the contents, and not the class definition. Thus methods are not serialized.

Here is a very basic sample with comments to facilitate its reading:

import java.util.*;

// This class implements "Serializable" to let the system know
// it's ok to do it. You as programmer are aware of that.
public class SerializationSample implements Serializable {

    // These attributes conform the "value" of the object.

    // These two will be serialized;
    private String aString = "The value of that string";
    private int    someInteger = 0;

    // But this won't since it is marked as transient.
    private transient List<File> unInterestingLongLongList;

    // Main method to test.
    public static void main( String [] args ) throws IOException  { 

        // Create a sample object, that contains the default values.
        SerializationSample instance = new SerializationSample();

        // The "ObjectOutputStream" class has the default 
        // definition to serialize an object.
        ObjectOutputStream oos = new ObjectOutputStream( 
                               // By using "FileOutputStream" we will 
                               // Write it to a File in the file system
                               // It could have been a Socket to another 
                               // machine, a database, an in memory array, etc.
                               new FileOutputStream(new File("o.ser")));

        // do the magic  
        oos.writeObject( instance );
        // close the writing.

When we run this program, the file "o.ser" is created and we can see what happened behind.

If we change the value of: someInteger to, for example Integer.MAX_VALUE, we may compare the output to see what the difference is.

Here's a screenshot showing precisely that difference:

alt text

Can you spot the differences? ;)

There is an additional relevant field in Java serialization: The serialversionUID but I guess this is already too long to cover it.

JavaScript get element by name

Method document.getElementsByName returns an array of elements. You should select first, for example.


How to decode jwt token in javascript without using a library?

If you're using Typescript or vanilla JavaScript, here's a zero-dependency, ready to copy-paste in your project simple function (building on @Rajan Maharjan 's answer).

This answer is particularly good, not only because it does not depend on any npm module, but also because it does not depend an any node.js built-in module (like Buffer) that some other solutions here are using and of course would fail in the browser (unless polyfilled, but there's no reason to do that in the first place). Additionally JSON.parse can fail at runtime and this version (especially in Typescript) will force handling of that. The JSDoc annotations will make future maintainers of your code thankful. :)

 * Returns a JS object representation of a Javascript Web Token from it's common encoded
 * string form.
 * @export
 * @template T the expected shape of the parsed token
 * @param {string} token a Javascript Web Token in base64 encoded, `.` separated form
 * @returns {(T | undefined)} an object-representation of the token
 * or undefined if parsing failed
export function getParsedJwt<T extends object = { [k: string]: string | number }>(
  token: string,
): T | undefined {
  try {
    return JSON.parse(atob(token.split('.')[1]))
  } catch {
    return undefined

For completion, here's the vanilla javascript version too:

 * Returns a JS object representation of a Javascript Web Token from it's common encoded
 * string form.
 * @export
 * @template T the expected shape of the parsed token
 * @param {string} token a Javascript Web Token in base64 encoded, `.` separated form
 * @returns {(object | undefined)} an object-representation of the token
 * or undefined if parsing failed
export function getParsedJwt(token) {
  try {
    return JSON.parse(atob(token.split('.')[1]))
  } catch (e) {
    return undefined

How much faster is C++ than C#?

As usual, it depends on the application. There are cases where C# is probably negligibly slower, and other cases where C++ is 5 or 10 times faster, especially in cases where operations can be easily SIMD'd.

How to make a WPF window be on top of all other windows of my app (not system wide)?

You need to set the owner property of the window.

You can show a window via showdialog in order to block your main window, or you can show it normal and have it ontop of the owner without blocking the owner.

here is a codeexample of the codebehind part - I left out all obvious stuff:

namespace StackoverflowExample
  public partial class MainWindow : Window
    public MainWindow()
    void NewWindowAsDialog(object sender, RoutedEventArgs e)
      Window myOwnedDialog = new Window();
      myOwnedDialog.Owner = this;
    void NormalNewWindow(object sender, RoutedEventArgs e)
      Window myOwnedWindow = new Window();
      myOwnedWindow.Owner = this;

Python 3 print without parenthesis

Use Autohotkey to make a macro. AHK is free and dead simple to install.

You could assign the macro to, say, alt-p:

!p::send print(){Left}

That will make alt-p put out print() and move your cursor to inside the parens.

Or, even better, to directly solve your problem, you define an autoreplace and limit its scope to when the open file has the .py extension:

#IfWinActive .py            ;;; scope limiter
:b*:print ::print(){Left}   ;;; I forget what b* does. The rest should be clear 
#IfWinActive                ;;; remove the scope limitation

This is a guaranteed, painless, transparent solution.

Deserialize JSON to ArrayList<POJO> using Jackson

I am also having the same problem. I have a json which is to be converted to ArrayList.

Account looks like this.

  Person p ;
  Related r ;


    String Name ;
    Address a ;

All of the above classes have been annotated properly. I have tried TypeReference>() {} but is not working.

It gives me Arraylist but ArrayList has a linkedHashMap which contains some more linked hashmaps containing final values.

My code is as Follows:

public T unmarshal(String responseXML,String c)
    ObjectMapper mapper = new ObjectMapper();

    AnnotationIntrospector introspector = new JacksonAnnotationIntrospector();


      this.targetclass = (T) mapper.readValue(responseXML,  new TypeReference<ArrayList<T>>() {});
    catch (JsonParseException e)
    catch (JsonMappingException e) {
    } catch (IOException e) {

    return this.targetclass;

I finally solved the problem. I am able to convert the List in Json String directly to ArrayList as follows:


     T targetClass ;

     public ArrayList<T> unmarshal(String jsonString)
        ObjectMapper mapper = new ObjectMapper();

        AnnotationIntrospector introspector = new JacksonAnnotationIntrospector();


        JavaType type = mapper.getTypeFactory().
                    constructCollectionType(ArrayList.class, targetclass.getClass()) ;
        Class c1 = this.targetclass.getClass() ;
        Class c2 = this.targetclass1.getClass() ;
            ArrayList<T> temp = (ArrayList<T>) mapper.readValue(jsonString,  type);
        return temp ;
       catch (JsonParseException e)
       catch (JsonMappingException e) {
       } catch (IOException e) {

     return null ;


How / can I display a console window in Intellij IDEA?

IntelliJ IDEA 14 & 15 & 2017:

View > Tool Windows > Terminal


Alt + F12

enter image description here enter image description here

How to align a div inside td element using CSS class

div { margin: auto; }

This will center your div.

Div by itself is a blockelement. Therefor you need to define the style to the div how to behave.

Using module 'subprocess' with timeout

Another option is to write to a temporary file to prevent the stdout blocking instead of needing to poll with communicate(). This worked for me where the other answers did not; for example on windows.

    outFile =  tempfile.SpooledTemporaryFile() 
    errFile =   tempfile.SpooledTemporaryFile() 
    proc = subprocess.Popen(args, stderr=errFile, stdout=outFile, universal_newlines=False)
    wait_remaining_sec = timeout

    while proc.poll() is None and wait_remaining_sec > 0:
        wait_remaining_sec -= 1

    if wait_remaining_sec <= 0:
        raise ProcessIncompleteError(proc, timeout)

    # read temp streams from start;;
    out =
    err =

Load a bitmap image into Windows Forms using open file dialog

You, can also try like this, PictureBox1.Image = Image.FromFile("<your ImagePath>" or <Dialog box result>);

How can I wrap text in a label using WPF?

try use this

lblresult.Content = lblresult.Content + "prime are :" + j + "\n";

Python Sets vs Lists

It depends on what you are intending to do with it.

Sets are significantly faster when it comes to determining if an object is present in the set (as in x in s), but are slower than lists when it comes to iterating over their contents.

You can use the timeit module to see which is faster for your situation.

Using IF..ELSE in UPDATE (SQL server 2005 and/or ACCESS 2007)

this should work

update table_name
  set column_b = case
                  when column_a = 1 then 'Y'
                  else null
  set column_c = case
                  when column_a = 2 then 'Y'
                  else null
  set column_d = case
                  when column_a = 3 then 'Y'
                  else null

the question is why would you want to do may want to rethink the data model. you can replace null with whatever you want.

Android toolbar center title and custom font

The ToolBar title is stylable. Any customization you make has to be made in the theme. I'll give you an example.

Toolbar layout:

<?xml version="1.0" encoding="utf-8"?>
    android:minHeight="@dimen/abc_action_bar_default_height_material" />


<style name="ToolBarStyle" parent="ToolBarStyle.Base"/>

<style name="ToolBarStyle.Base" parent="">
    <item name="popupTheme">@style/ThemeOverlay.AppCompat.Light</item>
    <item name="theme">@style/ThemeOverlay.AppCompat.Dark.ActionBar</item>

<style name="ToolBarStyle.Event" parent="ToolBarStyle">
    <item name="titleTextAppearance">@style/TextAppearance.Widget.Event.Toolbar.Title</item>

<style name="TextAppearance.Widget.Event.Toolbar.Title" parent="TextAppearance.Widget.AppCompat.Toolbar.Title">
    <!--Any text styling can be done here-->
    <item name="android:textStyle">normal</item>
    <item name="android:textSize">@dimen/event_title_text_size</item>

Safe width in pixels for printing web pages?

For printing I don't set any width and remove any obstacles which keep your print layout from having a dynamic width. Meaning if you make your browser window smaller and smaller, no content is cut/hidden but the document just gets longer. Like this, you can be sure that the rest will be handled by the printer/pdf-creator.

What about elements with a fixed width such as images or tables?


Options I can think of:

  • scale images down in your print CSS to a width which you can assume will fit in any case, use pt not px (but print will need more points/unit anyways, so this should hardly be a problem)
  • exclude from being printed


  • remove the fixed width
  • use landscape if you really have tables with loads of information
  • don't use tables for layout purposes
  • exclude from being printed
  • extract content, print it as paragraphs

or any other google result for combinations of: CSS, print, media, layout

Alternative to google finance api

I'd suggest using TradeKing's developer API. It is very good and free to use. All that is required is that you have an account with them and to my knowledge you don't have to carry a balance ... only to be registered.

Floating Div Over An Image

You've got the right idea. Looks to me like you just need to change .tag's position:relative to position:absolute, and add position:relative to .container.

using BETWEEN in WHERE condition

I think we can write like this : $this->db->where('accommodation >=', minvalue); $this->db->where('accommodation <=', maxvalue);

//without dollar($) sign It's work for me :)

upstream sent too big header while reading response header from upstream

I am not sure that the issue is related to what header php is sending. Make sure that the buffering is enabled. The simple way is to create a proxy.conf file:

proxy_redirect          off;
proxy_set_header        Host            $host;
proxy_set_header        X-Real-IP       $remote_addr;
proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
client_max_body_size    100m;
client_body_buffer_size 128k;
proxy_connect_timeout   90;
proxy_send_timeout      90;
proxy_read_timeout      90;
proxy_buffering         on;
proxy_buffer_size       128k;
proxy_buffers           4 256k;
proxy_busy_buffers_size 256k;

And a fascgi.conf file:

fastcgi_param  SCRIPT_FILENAME    $document_root$fastcgi_script_name;
fastcgi_param  QUERY_STRING       $query_string;
fastcgi_param  REQUEST_METHOD     $request_method;
fastcgi_param  CONTENT_TYPE       $content_type;
fastcgi_param  CONTENT_LENGTH     $content_length;
fastcgi_param  SCRIPT_NAME        $fastcgi_script_name;
fastcgi_param  REQUEST_URI        $request_uri;
fastcgi_param  DOCUMENT_URI       $document_uri;
fastcgi_param  DOCUMENT_ROOT      $document_root;
fastcgi_param  SERVER_PROTOCOL    $server_protocol;
fastcgi_param  GATEWAY_INTERFACE  CGI/1.1;
fastcgi_param  SERVER_SOFTWARE    nginx/$nginx_version;
fastcgi_param  REMOTE_ADDR        $remote_addr;
fastcgi_param  REMOTE_PORT        $remote_port;
fastcgi_param  SERVER_ADDR        $server_addr;
fastcgi_param  SERVER_PORT        $server_port;
fastcgi_param  SERVER_NAME        $server_name;
fastcgi_buffers 128 4096k;
fastcgi_buffer_size 4096k;
fastcgi_index  index.php;
fastcgi_param  REDIRECT_STATUS    200;

Next you need to call them in your default config server this way:

http {
  include    /etc/nginx/mime.types;
  include    /etc/nginx/proxy.conf;
  include    /etc/nginx/fastcgi.conf;
  index    index.html index.htm index.php;
  log_format   main '$remote_addr - $remote_user [$time_local]  $status '
    '"$request" $body_bytes_sent "$http_referer" '
    '"$http_user_agent" "$http_x_forwarded_for"';
  #access_log   /logs/access.log  main;
  sendfile     on;
  tcp_nopush   on;
 # ........

How to run Java program in command prompt

All you need to do is:

  • Build the mainjava class using the class path if any (optional)

    javac *.java [ -cp "wb.jar;"]

  • Create Manifest.txt file with content is:

    Main-Class: mainjava

  • Package the jar file for mainjava class

    jar cfm mainjava.jar Manifest.txt *.class

Then you can run this .jar file from cmd with class path (optional) and put arguments for it.

java [-cp "wb.jar;"] mainjava arg0 arg1 


In DB2 Display a table's definition

I just came across this query to describe a table in winsql

select NAME,TBNAME,COLTYPE,LENGTH,REMARKS,SCALE from sysibm.syscolumns
where tbcreator = 'Schema_name' and tbname='Table_name' ;

How to return a value from a Form in C#?

I just put into constructor something by reference, so the subform can change its value and main form can get new or modified object from subform.

Python Pandas : group by in group by and average?

I would simply do this, which literally follows what your desired logic was:


Two-way SSL clarification

What you call "Two-Way SSL" is usually called TLS/SSL with client certificate authentication.

In a "normal" TLS connection to only the client verifies that it is indeed communicating with the server for The server doesn't know who the client is. If the server wants to authenticate the client the usual thing is to use passwords, so a client needs to send a user name and password to the server, but this happens inside the TLS connection as part of an inner protocol (e.g. HTTP) it's not part of the TLS protocol itself. The disadvantage is that you need a separate password for every site because you send the password to the server. So if you use the same password on for example PayPal and MyPonyForum then every time you log into MyPonyForum you send this password to the server of MyPonyForum so the operator of this server could intercept it and try it on PayPal and can issue payments in your name.

Client certificate authentication offers another way to authenticate the client in a TLS connection. In contrast to password login, client certificate authentication is specified as part of the TLS protocol. It works analogous to the way the client authenticates the server: The client generates a public private key pair and submits the public key to a trusted CA for signing. The CA returns a client certificate that can be used to authenticate the client. The client can now use the same certificate to authenticate to different servers (i.e. you could use the same certificate for PayPal and MyPonyForum without risking that it can be abused). The way it works is that after the server has sent its certificate it asks the client to provide a certificate too. Then some public key magic happens (if you want to know the details read RFC 5246) and now the client knows it communicates with the right server, the server knows it communicates with the right client and both have some common key material to encrypt and verify the connection.

Twitter Bootstrap Modal Form Submit

You can also cheat in some way by hidding a submit button on your form and triggering it when you click on your modal button.

jQuery text() and newlines

Try this:

$(someElem).html('this<br> has<br> newlines);

Determine if string is in list in JavaScript

Using indexOf(it doesn’t work with IE8).

if (['apple', 'cherry', 'orange', 'banana'].indexOf(value) >= 0) {
    // found

To support IE8, you could implement Mozilla’s indexOf.

if (!Array.prototype.indexOf) {
    // indexOf polyfill code here

Regular Expressions via String.prototype.match (docs).

if (fruit.match(/^(banana|lemon|mango|pineapple)$/)) {


Escape double quotes for JSON in Python

Why not do string suppression with triple quotes:

>>> s = """my string with "some" double quotes"""
>>> print s
my string with "some" double quotes

How to apply CSS to iframe?

If you want to reuse CSS and JavaScript from the main page maybe you should consider replacing <IFRAME> with a Ajax loaded content. This is more SEO friendly now when search bots are able to execute JavaScript.

This is jQuery example that includes another html page into your document. This is much more SEO friendly than iframe. In order to be sure that the bots are not indexing the included page just add it to disallow in robots.txt

    <script src="/js/jquery.js" type="text/javascript"></script>
    <div id='include-from-outside'></div>
    <script type='text/javascript'>

You could also include jQuery directly from Google: - this means optional auto-inclusion of newer versions and some significant speed increase. Also, means that you have to trust them for delivering you just the jQuery ;)

Reading a key from the Web.Config using ConfigurationManager

I found this solution to be quite helpful. It uses C# 4.0 DynamicObject to wrap the ConfigurationManager. So instead of accessing values like this:


you access them as a property:

dynamic appSettings = new AppSettingsWrapper();

EDIT: Adding code snippet in case link becomes stale:

public class AppSettingsWrapper : DynamicObject
     private NameValueCollection _items;

    public AppSettingsWrapper()
        _items = ConfigurationManager.AppSettings;

     public override bool TryGetMember(GetMemberBinder binder, out object result)
        result = _items[binder.Name];
        return result != null;

Convert JSON String to JSON Object c#

JObject defines method Parse for this:

JObject json = JObject.Parse(str);

You might want to refer to Json.NET documentation.

What does it mean: The serializable class does not declare a static final serialVersionUID field?

it must be changed whenever anything changes that affects the serialization (additional fields, removed fields, change of field order, ...)

That's not correct, and you will be unable to cite an authoriitative source for that claim. It should be changed whenever you make a change that is incompatible under the rules given in the Versioning of Serializable Objects section of the Object Serialization Specification, which specifically does not include additional fields or change of field order, and when you haven't provided readObject(), writeObject(), and/or readResolve() or /writeReplace() methods and/or a serializableFields declaration that could cope with the change.

How to query as GROUP BY in django?

You need to do custom SQL as exemplified in this snippet:

Custom SQL via subquery

Or in a custom manager as shown in the online Django docs:

Adding extra Manager methods

How can I show/hide component with JSF?

One obvious solution would be to use javascript (which is not JSF). To implement this by JSF you should use AJAX. In this example, I use a radio button group to show and hide two set of components. In the back bean, I define a boolean switch.

private boolean switchComponents;

public boolean isSwitchComponents() {
    return switchComponents;

public void setSwitchComponents(boolean switchComponents) {
    this.switchComponents = switchComponents;

When the switch is true, one set of components will be shown and when it is false the other set will be shown.

 <h:selectOneRadio value="#{backbean.switchValue}">
   <f:selectItem itemLabel="showComponentSetOne" itemValue='true'/>
   <f:selectItem itemLabel="showComponentSetTwo" itemValue='false'/>
   <f:ajax event="change" execute="@this" render="componentsRoot"/>

<H:panelGroup id="componentsRoot">
     <h:panelGroup rendered="#{backbean.switchValue}">
       <!--switchValue to be shown on switch value == true-->

   <h:panelGroup rendered="#{!backbean.switchValue}">
      <!--switchValue to be shown on switch value == false-->

Note: on the ajax event we render components root. because components which are not rendered in the first place can't be re-rendered on the ajax event.

Also, note that if the "componentsRoot" and radio buttons are under different component hierarchy. you should reference it from the root (form root).

How to draw a rectangle around a region of interest in python

As the other answers said, the function you need is cv2.rectangle(), but keep in mind that the coordinates for the bounding box vertices need to be integers if they are in a tuple, and they need to be in the order of (left, top) and (right, bottom). Or, equivalently, (xmin, ymin) and (xmax, ymax).

Issue when importing dataset: `Error in scan(...): line 1 did not have 145 elements`

This error is pretty self-explanatory. There seem to be data missing in the first line of your data file (or second line, as the case may be since you're using header = TRUE).

Here's a mini example:

## Create a small dataset to play with
cat("V1 V2\nFirst 1 2\nSecond 2\nThird 3 8\n", file="test.txt")

R automatically detects that it should expect rownames plus two columns (3 elements), but it doesn't find 3 elements on line 2, so you get an error:

read.table("test.txt", header = TRUE)
# Error in scan(file, what, nmax, sep, dec, quote, skip, nlines, na.strings,  : 
#   line 2 did not have 3 elements

Look at the data file and see if there is indeed a problem:

cat(readLines("test.txt"), sep = "\n")
# V1 V2
# First 1 2
# Second 2
# Third 3 8

Manual correction might be needed, or we can assume that the value first value in the "Second" row line should be in the first column, and other values should be NA. If this is the case, fill = TRUE is enough to solve your problem.

read.table("test.txt", header = TRUE, fill = TRUE)
#        V1 V2
# First   1  2
# Second  2 NA
# Third   3  8

R is also smart enough to figure it out how many elements it needs even if rownames are missing:

cat("V1 V2\n1\n2 5\n3 8\n", file="test2.txt")
cat(readLines("test2.txt"), sep = "\n")
# V1 V2
# 1
# 2 5
# 3 8
read.table("test2.txt", header = TRUE)
# Error in scan(file, what, nmax, sep, dec, quote, skip, nlines, na.strings,  : 
#   line 1 did not have 2 elements
read.table("test2.txt", header = TRUE, fill = TRUE)
#   V1 V2
# 1  1 NA
# 2  2  5
# 3  3  8

How to get the ActionBar height?


    int actionBarHeight;
    int[] abSzAttr;
        abSzAttr = new int[] { android.R.attr.actionBarSize };
    } else {
        abSzAttr = new int[] { R.attr.actionBarSize };
    TypedArray a = obtainStyledAttributes(abSzAttr);
    actionBarHeight = a.getDimensionPixelSize(0, -1);



How can I get a value from a map?

Unfortunately std::map::operator[] is a non-const member function, and you have a const reference.

You either need to change the signature of function or do:

MAP::const_iterator pos = map.find("string");
if (pos == map.end()) {
    //handle the error
} else {
    std::string value = pos->second;

operator[] handles the error by adding a default-constructed value to the map and returning a reference to it. This is no use when all you have is a const reference, so you will need to do something different.

You could ignore the possibility and write string value = map.find("string")->second;, if your program logic somehow guarantees that "string" is already a key. The obvious problem is that if you're wrong then you get undefined behavior.

Saving plots (AxesSubPlot) generated from python pandas with matplotlib's savefig

this may be a simpler approach:




Django request.GET

def search(request):
if 'q' in request.GET.keys():
    message = 'You submitted: %r' % request.GET['q']
    message = 'You submitted nothing!'

return HttpResponse(message)

you can use if ... in too.

How to move a file?

After Python 3.4, you can also use pathlib's class Path to move file.

from pathlib import Path


Can I use multiple versions of jQuery on the same page?

Absolutely, yes you can. This link contains details about how you can achieve that:

How can I view an old version of a file with Git?

Doing this by date looks like this if the commit happened within the last 90 days:

git show HEAD@{2013-02-25}:./fileInCurrentDirectory.txt

Note that HEAD@{2013-02-25} means "where HEAD was on 2013-02-25" in this repository (using the reflog), not "the last commit before 2013-02-25 in this branch in history".

This is important! It means that, by default, this method only works for history within the last 90 days. Otherwise, you need to do this:

git show $(git rev-list -1 --before="2013-02-26" HEAD):./fileInCurrentDirectory.txt

Replace specific text with a redacted version using Python

You can do it using named-entity recognition (NER). It's fairly simple and there are out-of-the-shelf tools out there to do it, such as spaCy.

NER is an NLP task where a neural network (or other method) is trained to detect certain entities, such as names, places, dates and organizations.


Sponge Bob went to South beach, he payed a ticket of $200!
I know, Michael is a good person, he goes to McDonalds, but donates to charity at St. Louis street.


NER with spacy

Just be aware that this is not 100%!

Here are a little snippet for you to try out:

import spacy

phrases = ['Sponge Bob went to South beach, he payed a ticket of $200!', 'I know, Michael is a good person, he goes to McDonalds, but donates to charity at St. Louis street.']
nlp = spacy.load('en')
for phrase in phrases:
   doc = nlp(phrase)
   replaced = ""
   for token in doc:
      if token in doc.ents:
         replaced+="XXXX "
         replaced+=token.text+" "

Read more here:

You could, instead of replacing with XXXX, replace based on the entity type, like:

if ent.label_ == "PERSON":
   replaced += "<PERSON> "


import re, random

personames = ["Jack", "Mike", "Bob", "Dylan"]

phrase = re.replace("<PERSON>", random.choice(personames), phrase)

Adb install failure: INSTALL_CANCELED_BY_USER

Sometimes the application is bad generated: bad signed or bad aligned and report a mistake.

Check your jarsigner and zipaligned commands.

Android Studio: Drawable Folder: How to put Images for Multiple dpi?

New -> Batch Drawable Import -> Click on Add button -> Select image -> Select Target Resolution, Target Name, Format -> Ok

Function to clear the console in R and RStudio

cat("\f") may be easier to remember than cat("\014").

It works fine for me on Windows 10.

R ggplot2: stat_count() must not be used with a y aesthetic error in Bar graph

I was looking for the same and this may also work

p.Wages.all.A_MEAN <- Wages.all %>%
                  group_by(`Career Cluster`, Year)%>%
                  summarize(ANNUAL.MEAN.WAGE = mean(A_MEAN))

names(p.Wages.all.A_MEAN) [1] "Career Cluster" "Year" "ANNUAL.MEAN.WAGE"

p.Wages.all.a.mean <- ggplot(p.Wages.all.A_MEAN, aes(Year, ANNUAL.MEAN.WAGE , color= `Career Cluster`))+
                  geom_point(aes(col=`Career Cluster` ), pch=15, size=2.75, alpha=1.5/4)+
                  theme(axis.text.x = element_text(color="#993333",  size=10, angle=0)) #face="italic",

Overlay normal curve to histogram in R

Here's a nice easy way I found:

h <- hist(g, breaks = 10, density = 10,
          col = "lightgray", xlab = "Accuracy", main = "Overall") 
xfit <- seq(min(g), max(g), length = 40) 
yfit <- dnorm(xfit, mean = mean(g), sd = sd(g)) 
yfit <- yfit * diff(h$mids[1:2]) * length(g) 

lines(xfit, yfit, col = "black", lwd = 2)

Can I set state inside a useEffect hook

Effects are always executed after the render phase is completed even if you setState inside the one effect, another effect will read the updated state and take action on it only after the render phase.

Having said that its probably better to take both actions in the same effect unless there is a possibility that b can change due to reasons other than changing a in which case too you would want to execute the same logic

SecurityError: The operation is insecure - window.history.pushState()

You should try not open the file with a folder-explorer method (i.e. file://), but open that file from http:// (i.e. from http://localhost/)

How to parse JSON without JSON.NET library?

You can use DataContractJsonSerializer. See this link for more details.

Memcache Vs. Memcached

(PartlyStolen from ServerFault)

I think that both are functionally the same, but they simply have different authors, and the one is simply named more appropriately than the other.

Here is a quick backgrounder in naming conventions (for those unfamiliar), which explains the frustration by the question asker: For many *nix applications, the piece that does the backend work is called a "daemon" (think "service" in Windows-land), while the interface or client application is what you use to control or access the daemon. The daemon is most often named the same as the client, with the letter "d" appended to it. For example "imap" would be a client that connects to the "imapd" daemon.

This naming convention is clearly being adhered to by memcache when you read the introduction to the memcache module (notice the distinction between memcache and memcached in this excerpt):

Memcache module provides handy procedural and object oriented interface to memcached, highly effective caching daemon, which was especially designed to decrease database load in dynamic web applications.

The Memcache module also provides a session handler (memcache).

More information about memcached can be found at »

The frustration here is caused by the author of the PHP extension which was badly named memcached, since it shares the same name as the actual daemon called memcached. Notice also that in the introduction to memcached (the php module), it makes mention of libmemcached, which is the shared library (or API) that is used by the module to access the memcached daemon:

memcached is a high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load.

This extension uses libmemcached library to provide API for communicating with memcached servers. It also provides a session handler (memcached).

Information about libmemcached can be found at »

What is the difference between =Empty and IsEmpty() in VBA (Excel)?

Empty refers to a variable being at its default value. So if you check if a cell with a value of 0 = Empty then it would return true.

IsEmpty refers to no value being initialized.

In a nutshell, if you want to see if a cell is empty (as in nothing exists in its value) then use IsEmpty. If you want to see if something is currently in its default value then use Empty.

How to rearrange Pandas column sequence?

Feel free to disregard this solution as subtracting a list from an Index does not preserve the order of the original Index, if that's important.

In [61]: df.reindex(columns=pd.Index(['x', 'y']).append(df.columns - ['x', 'y']))
    x  y  a  b
0   3 -1  1  2
1   6 -2  2  4
2   9 -3  3  6
3  12 -4  4  8

Detecting Back Button/Hash Change in URL

Try simple & lightweight PathJS lib.

Simple example:"#/page").to(function(){

Get Android .apk file VersionName or VersionCode WITHOUT installing apk


var ver: String = packageManager.getPackageInfo(packageName, 0).versionName

SMTPAuthenticationError when sending mail using gmail and python

Your code looks correct but sometimes google blocks an IP when you try to send a email from an unusual location. You can try to unblock it by visiting from the IP and following the prompts.


What does yield mean in PHP?

With yield you can easily describe the breakpoints between multiple tasks in a single function. That's all, there is nothing special about it.

$closure = function ($injected1, $injected2, ...){
    $returned = array();
    //task1 on $injected1
    $returned[] = $returned1;
//I need a breakpoint here!!!!!!!!!!!!!!!!!!!!!!!!!
    //task2 on $injected2
    $returned[] = $returned2;
    return $returned;
$returned = $closure($injected1, $injected2, ...);

If task1 and task2 are highly related, but you need a breakpoint between them to do something else:

  • free memory between processing database rows
  • run other tasks which provide dependency to the next task, but which are unrelated by understanding the current code
  • doing async calls and wait for the results
  • and so on ...

then generators are the best solution, because you don't have to split up your code into many closures or mix it with other code, or use callbacks, etc... You just use yield to add a breakpoint, and you can continue from that breakpoint if you are ready.

Add breakpoint without generators:

$closure1 = function ($injected1){
    //task1 on $injected1
    return $returned1;
$closure2 = function ($injected2){
    //task2 on $injected2
    return $returned1;
$returned1 = $closure1($injected1);
//breakpoint between task1 and task2
$returned2 = $closure2($injected2);

Add breakpoint with generators

$closure = function (){
    $injected1 = yield;
    //task1 on $injected1
    $injected2 = (yield($returned1));
    //task2 on $injected2
    $injected3 = (yield($returned2));
$generator = $closure();
$returned1 = $generator->send($injected1);
//breakpoint between task1 and task2
$returned2 = $generator->send($injected2);
$returnedN = $generator->send($injectedN);

note: It is easy to make mistake with generators, so always write unit tests before you implement them! note2: Using generators in an infinite loop is like writing a closure which has infinite length...

iterating quickly through list of tuples

I think that you can use

for j,k in my_list:
  [ ... stuff ... ]

Iterating over and deleting from Hashtable in Java

So you know the key, value pair that you want to delete in advance? It's just much clearer to do this, then:

 for (K key: table.keySet()) {
    // do whatever you need to do with the rest of the keys

GET URL parameter in PHP

Use this:

$parameter = $_SERVER['QUERY_STRING'];
echo $parameter;

Or just use:

$parameter = $_GET['link'];
echo $parameter ;

Java: unparseable date exception

From Oracle docs, Date.toString() method convert Date object to a String of the specific form - do not use toString method on Date object. Try to use:

String stringDate = new SimpleDateFormat(YOUR_STRING_PATTERN).format(yourDateObject);

Next step is parse stringDate to Date:

Date date = new SimpleDateFormat(OUTPUT_PATTERN).parse(stringDate);

Note that, parse method throws ParseException

the MySQL service on local computer started and then stopped

Such a problem can very often come due to configuration errors.

Vivek Sethi mentioned 20th December 2012 that it is possible to get logging in the console by running the following command:

C:\Windows\system32>"C:\Program Files\MySQL\MySQL Server 5.5\bin\mysqld" --defaults-file="C:\Program Files\MySQL\MySQL Server 5.5\my.ini" --standalone --console

Right-clicking on my service in Windows 10, I recognized the --defaults-file= parameter, and with console logging I was able to see what was wrong in my configuration. In my case the path to datadir= and secure-file-priv= was wrong. I hope others can be empowered as well by being able to see logging details in the console. Good luck!

adding onclick event to dynamically added button?

Try this:

var inputTag = document.createElement("div");              
inputTag.innerHTML = "<input type = 'button' value = 'oooh' onClick = 'your_function_name()'>";    

This creates a button inside a DIV which works perfectly!

IP to Location using Javascript

A better way is to skip the "middle man" (ip)

jQuery.get("", function(response) {
}, "jsonp");

This gives you the IP, the city, the country, etc

Laravel Eloquent groupBy() AND also return count of each group

Works that way as well, a bit more tidy. getQuery() just returns the underlying builder, which already contains the table reference.

$browser_total_raw = DB::raw('count(*) as total');
$user_info = Usermeta::getQuery()
                     ->select('browser', $browser_total_raw)

includes() not working in all browsers

Here is solution ( ref : )

if (!Array.prototype.includes) {
  Object.defineProperty(Array.prototype, 'includes', {
    value: function (searchElement, fromIndex) {

      if (this == null) {
        throw new TypeError('"this" is null or not defined');

      // 1. Let O be ? ToObject(this value).
      var o = Object(this);

      // 2. Let len be ? ToLength(? Get(O, "length")).
      var len = o.length >>> 0;

      // 3. If len is 0, return false.
      if (len === 0) {
        return false;

      // 4. Let n be ? ToInteger(fromIndex).
      //    (If fromIndex is undefined, this step produces the value 0.)
      var n = fromIndex | 0;

      // 5. If n = 0, then
      //  a. Let k be n.
      // 6. Else n < 0,
      //  a. Let k be len + n.
      //  b. If k < 0, let k be 0.
      var k = Math.max(n >= 0 ? n : len - Math.abs(n), 0);

      function sameValueZero(x, y) {
        return x === y || (typeof x === 'number' && typeof y === 'number' && isNaN(x) && isNaN(y));

      // 7. Repeat, while k < len
      while (k < len) {
        // a. Let elementK be the result of ? Get(O, ! ToString(k)).
        // b. If SameValueZero(searchElement, elementK) is true, return true.
        if (sameValueZero(o[k], searchElement)) {
          return true;
        // c. Increase k by 1. 

      // 8. Return false
      return false;

How do I resolve git saying "Commit your changes or stash them before you can merge"?

To keep record of your newly created files while resolving this issue:

If you have newly created files, you can create a patch of local changes, pull in remote merges and apply your local patch after the remote merge is complete as defined step by step below:

  1. Stage your local changes. (do not commit). Staging is required to create patch of new created files (as they are still untracked)

git add .

  1. Create a patch to keep record

git diff --cached > mypatch.patch

  1. Discard local changes and delete new local files

git reset --hard

  1. Pull changes

git pull

  1. Apply your patch

git apply mypatch.patch

Git will merge changes and create .rej files for changes which are not merged.

As suggested by Anu, if you have issues applying patch, try:

git apply --reject --whitespace=fix mypatch.patch This answer git: patch does not apply talks in detail about this issue

Enjoy your continued work on your feature, and commit your local changes when done.

Git: How to remove remote origin from Git repo

first will change push remote url

git remote set-url --push origin https://newurl

second will change fetch remote url

git remote set-url origin https://newurl

What is the difference between atomic / volatile / synchronized?

A volatile + synchronization is a fool proof solution for an operation(statement) to be fully atomic which includes multiple instructions to the CPU.

Say for eg:volatile int i = 2; i++, which is nothing but i = i + 1; which makes i as the value 3 in the memory after the execution of this statement. This includes reading the existing value from memory for i(which is 2), load into the CPU accumulator register and do with the calculation by increment the existing value with one(2 + 1 = 3 in accumulator) and then write back that incremented value back to the memory. These operations are not atomic enough though the value is of i is volatile. i being volatile guarantees only that a SINGLE read/write from memory is atomic and not with MULTIPLE. Hence, we need to have synchronized also around i++ to keep it to be fool proof atomic statement. Remember the fact that a statement includes multiple statements.

Hope the explanation is clear enough.

How to reset Android Studio

For MaxOSX:

rm -rfv ~/Library/Application\ Support/AndroidStudio*
rm -rfv ~/Library/Preferences/AndroidStudio*
rm -rfv ~/Library/Caches/AndroidStudio*
rm -rfv ~/Library/Logs/AndroidStudio*
rm -rfv ~/.AndroidStudio*

For Android Studio 1.2.2 version, config path is ~/Library/Application\ Support/AndroidStudio1.2/ and ~/Library/Preferences/AndroidStudio1.2, so it's better to rm matching prefix.

How to find whether MySQL is installed in Red Hat?

yum list installed | grep mysql

Then if it's not installed you can do (as root)

yum install mysql -y

C: printf a float value

printf("%9.6f", myFloat) specifies a format with 9 total characters: 2 digits before the dot, the dot itself, and six digits after the dot.

How can I change the date format in Java?


    "23/01/2017" ,  
    DateTimeFormatter.ofPattern( "dd/MM/uuuu" , Locale.UK ) 
    DateTimeFormatter.ofPattern( "uuuu/MM/dd" , Locale.UK )


Avoid legacy date-time classes

The answer by Christopher Parker is correct but outdated. The troublesome old date-time classes such as java.util.Date, java.util.Calendar, and java.text.SimpleTextFormat are now legacy, supplanted by the java.time classes.

Using java.time

Parse the input string as a date-time object, then generate a new String object in the desired format.

The LocalDate class represents a date-only value without time-of-day and without time zone.

DateTimeFormatter fIn = DateTimeFormatter.ofPattern( "dd/MM/uuuu" , Locale.UK );  // As a habit, specify the desired/expected locale, though in this case the locale is irrelevant.
LocalDate ld = LocalDate.parse( "23/01/2017" , fIn );

Define another formatter for the output.

DateTimeFormatter fOut = DateTimeFormatter.ofPattern( "uuuu/MM/dd" , Locale.UK );
String output = ld.format( fOut );


By the way, consider using standard ISO 8601 formats for strings representing date-time values.

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

Where to obtain the java.time classes?

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.


UPDATE: The Joda-Time project is now in maintenance mode, with the team advising migration to the java.time classes. This section here is left for the sake of history.

For fun, here is his code adapted for using the Joda-Time library.

// © 2013 Basil Bourque. This source code may be used freely forever by anyone taking full responsibility for doing so.
// import org.joda.time.*;
// import org.joda.time.format.*;

final String OLD_FORMAT = "dd/MM/yyyy";
final String NEW_FORMAT = "yyyy/MM/dd";

// August 12, 2010
String oldDateString = "12/08/2010";
String newDateString;

DateTimeFormatter formatterOld = DateTimeFormat.forPattern(OLD_FORMAT);
DateTimeFormatter formatterNew = DateTimeFormat.forPattern(NEW_FORMAT);
LocalDate localDate = formatterOld.parseLocalDate( oldDateString );
newDateString = formatterNew.print( localDate );

Dump to console…

System.out.println( "localDate: " + localDate );
System.out.println( "newDateString: " + newDateString );

When run…

localDate: 2010-08-12
newDateString: 2010/08/12

Transparent background on winforms?

Should it have anything to do with "opacity" of the form / its background ? Did you try opacity = 0

Also see if this CP article helps:

How to convert a string from uppercase to lowercase in Bash?

Note that tr can only handle plain ASCII, making any tr-based solution fail when facing international characters.

Same goes for the bash 4 based ${x,,} solution.

The awk tool, on the other hand, properly supports even UTF-8 / multibyte input.

val=$(echo "$y" | awk '{print tolower($0)}')
string="$val world"

Answer courtesy of liborw.

PHP: Count a stdClass object

Just use this

foreach ($object as $key =>$value)

the variable $i is number of keys.

Eclipse: Java was started but returned error code=13

I also faced the error code when i upgraded my java version to 1.8. The problem was with my eclipse.

My jdk which was installed on my system is of 32 - bit and my eclipse was of 64 - bit.

So solve this problem i downloaded the 32 - bit eclipse.

IMO this Architecture miss match problem

Plese match your architecture type of JDK and eclipse.

how to redirect to home page


var re = /^https?:\/\/[^/]+/i;
window.location.href = re.exec(window.location.href)[0];

is what you're looking for?

Call a Javascript function every 5 seconds continuously

As best coding practices suggests, use setTimeout instead of setInterval.

function foo() {

    // your function code here

    setTimeout(foo, 5000);


Please note that this is NOT a recursive function. The function is not calling itself before it ends, it's calling a setTimeout function that will be later call the same function again.

Android Studio Checkout Github Error "CreateProcess=2" (Windows)

I've solved the problem , and I will explain how :

  1. Download Github For Windows client and install it.
  2. After The client successfully installed , connect it with your github account.It should be easy , just follow the wizard.
  3. Then you should add git.exe location to your "Path Variable". The location you should add will probably be something like : C:\Users\Your_Username\AppData\Local\GitHub\PortableGit_ca477551eeb4aea0e4ae9fcd3358bd96720bb5c8\bin

Alternatively , if you don't want to add to environment variables. You can open the android studio and go to : Settings -> Version Control -> Git In text box next to "Path to Git Executable" you will see "git.exe" , just give it a full path like so : C:\Users\Your_Username\AppData\Local\GitHub\PortableGit_ca477551eeb4aea0e4ae9fcd3358bd96720bb5c8\bin\git.exe

Hope it saved your time . Happy coding :)

EDIT : For latest Github for windows versions some can find the git.exe under "...\cmd\git.exe" rather than "...\bin\git.exe".

Override default Spring-Boot settings in Junit Test

Spring Boot automatically loads src/test/resources/, if following annotations are used


So, rename to to utilize auto configuration.

If you only need to load the properties file (into the Environment) you can also use the following, as explained here

@ContextConfiguration(initializers = ConfigFileApplicationContextInitializer.class) 

[Update: Overriding certain properties for testing]

  1. Add src/main/resources/
  2. Annotate test class with @ActiveProfiles("test").

This loads and then properties into application context for the test case, as per rules defined here.

Demo -

Polymorphism: Why use "List list = new ArrayList" instead of "ArrayList list = new ArrayList"?

I guess the core of your question is why to program to an interface, not to an implementation

Simply because an interface gives you more abstraction, and makes the code more flexible and resilient to changes, because you can use different implementations of the same interface(in this case you may want to change your List implementation to a linkedList instead of an ArrayList ) without changing its client.

Adding a column after another column within SQL

Assuming MySQL (EDIT: posted before the SQL variant was supplied):

ALTER TABLE myTable ADD myNewColumn VARCHAR(255) AFTER myOtherColumn

The AFTER keyword tells MySQL where to place the new column. You can also use FIRST to flag the new column as the first column in the table.

Programmatically Creating UILabel

UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(20, 30, 300, 50)];
label.backgroundColor = [UIColor clearColor];
label.textAlignment = NSTextAlignmentCenter;
label.textColor = [UIColor whiteColor];
label.numberOfLines = 0;
label.lineBreakMode = UILineBreakModeWordWrap;
label.text = @"Your Text";
[self.view addSubview:label];

Join two sql queries

If you assume that values exist for all activities in both years then just do an inner join as follows

 select act.activity, t1.amount as "Total 2009", t2.amount as "Total 2008"
from Activities as act,
    (select activityid,  SUM(Amount) as amount
    from Activities, Incomes
    where Activities.UnitName = ? AND
          Incomes.ActivityId = Activities.ActivityID
    GROUP BY Activityid) as t1,
    (select activityid, SUM(Amount) as amount
    from Activities, Incomes2008
    where Activities.UnitName = ? AND
          Incomes2008.ActivityId = Activities.ActivityID
    GROUP BY Activityid) as t2
    WHERE t1.activityid= t2.activityid
    AND act.activityId = t1.activityId
    ORDER BY act.activity

If you can't assume this, then look at doing an outer join

How can I check if a string is a number?

You should use the TryParse method for the int

string text1 = "x";
    int num1;
    bool res = int.TryParse(text1, out num1);
    if (res == false)
        // String is not a number.

Passing Variable through JavaScript from one html page to another page

Without reading your code but just your scenario, I would solve by using localStorage. Here's an example, I'll use prompt() for short.

On page1:

window.onload = function() {
   var getInput = prompt("Hey type something here: ");

On page2:

window.onload = alert(localStorage.getItem("storageName"));

You can also use cookies but localStorage allows much more spaces, and they aren't sent back to servers when you request pages.

Convert JSON to DataTable

There is an easier method than the other answers here, which require first deserializing into a c# class, and then turning it into a datatable.

It is possible to go directly to a datatable, with JSON.NET and code like this:

DataTable dt = (DataTable)JsonConvert.DeserializeObject(json, (typeof(DataTable)));

How to check if an integer is in a given range?

I don't see how that's not elegant, but if you repeat the expression often, then it's a good idea to put it into a method, e.g.

class MathUtil
   public static boolean betweenExclusive(int x, int min, int max)
       return x>min && x<max;    

This is particularly true if you mix exclusive and inclusive comparisons. The method name can help avoid typos, such as using < when <= should have been used. The method can also take care of ensuring that min < max etc..

How to wait for a JavaScript Promise to resolve before resuming function?

You can do it manually. (I know, that that isn't great solution, but..) use while loop till the result hasn't a value

kickOff().then(function(result) {
       if (result === undefined) continue;
       else {

How to find whether a number belongs to a particular range in Python?

print 'yes' if 0 < x < 0.5 else 'no'

range() is for generating arrays of consecutive integers

In C#, what's the difference between \n and \r\n?

The Difference

There are a few characters which can indicate a new line. The usual ones are these two:

* '\n' or '0x0A' (10 in decimal) -> This character is called "Line Feed" (LF).
* '\r' or '0x0D' (13 in decimal) -> This one is called "Carriage return" (CR).

Different Operating Systems handle newlines in a different way. Here is a short list of the most common ones:

* DOS and Windows

They expect a newline to be the combination of two characters, namely '\r\n' (or 13 followed by 10).

* Unix (and hence Linux as well)

Unix uses a single '\n' to indicate a new line.

* Mac

Macs use a single '\r'.

Taken from Here

Is there a way to change the spacing between legend items in ggplot2?

Use any of these

legend.spacing = unit(1,"cm")
legend.spacing.x = unit(1,"cm")
legend.spacing.y = unit(1,"cm")

Remove lines that contain certain string

Regex is a little quicker than the accepted answer (for my 23 MB test file) that I used. But there isn't a lot in it.

import re

bad_words = ['bad', 'naughty']

regex = f"^.*(:{'|'.join(bad_words)}).*\n"
subst = ""

with open('oldfile.txt') as oldfile:
    lines =

result = re.sub(regex, subst, lines, re.MULTILINE) 

with open('newfile.txt', 'w') as newfile:

enter image description here

Relationship between hashCode and equals method in Java

See JavaDoc of java.lang.Object

In hashCode() it says:

If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.

(Emphasis by me).

If you only override equals() and not hashCode() your class violates this contract.

This is also said in the JavaDoc of the equals() method:

Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

2D arrays in Python

If you are concerned about memory footprint, the Python standard library contains the array module; these arrays contain elements of the same type.

Print series of prime numbers in python

How about this? Reading all the suggestions I used this:

prime=[2]+[num for num in xrange(3,m+1,2) if all(num%i!=0 for i in range(2,int(math.sqrt(num))+1))]

Prime numbers up to 1000000

root@nfs:/pywork# time python


real 0m6.600s

user 0m6.532s

sys 0m0.036s

PHP Function Comments

You can get the comments of a particular method by using the ReflectionMethod class and calling ->getDocComment().

StringIO in Python3

when i write import StringIO it says there is no such module.

From What’s New In Python 3.0:

The StringIO and cStringIO modules are gone. Instead, import the io module and use io.StringIO or io.BytesIO for text and data respectively.


A possibly useful method of fixing some Python 2 code to also work in Python 3 (caveat emptor):

    from StringIO import StringIO ## for Python 2
except ImportError:
    from io import StringIO ## for Python 3

Note: This example may be tangential to the main issue of the question and is included only as something to consider when generically addressing the missing StringIO module. For a more direct solution the message TypeError: Can't convert 'bytes' object to str implicitly, see this answer.

Is it possible to set a timeout for an SQL query on Microsoft SQL server?

It sounds like more of an architectual issue, and any timeout/disconnect you can do would be more or less a band-aid. This has to be solved on SQL server side, by the way of read-only replica, transaction log shipping (to give you a read-only server to connect to), replication and such. Basically you give the DMZ sql server that heavy read can go to without killing stuff. This is very common. A well-designed SQL system won't be taken down by DDoS - that'd be like a car that dies if you step on the gas.

That said, if you are at the liberty to change the code, you could guesstimate if the query is too heavy and you could either reject or return only X rows in your stored procedure. If you are mated to some reporting tool and such and can't control the SELECT it generates, you could point it to a view and then do the safety valve in the view.

Also, if up-to-the-minute freshness isn't critical and you could compromise on that, like monthly sales data, then compiling a physical table of complex joins by job to avoid complex joins might do the trick - that way everything would be sub-second per query.

It entirely depends on what you are doing, but there is always a solution. Sometimes it takes extra coding to optimize it, sometimes it takes extra money to get you the secondary read-only DB, sometimes it needs time and attention in index tuning.

So it entirely depends, but I'd start with "what can I compromise? what can I change?" and go from there.

How to loop and render elements in React.js without an array of objects to map?

Array.from() takes an iterable object to convert to an array and an optional map function. You could create an object with a .length property as follows:

return Array.from({length: this.props.level}, (item, index) => 
  <span className="indent" key={index}></span>

Usage of __slots__?

You have — essentially — no use for __slots__.

For the time when you think you might need __slots__, you actually want to use Lightweight or Flyweight design patterns. These are cases when you no longer want to use purely Python objects. Instead, you want a Python object-like wrapper around an array, struct, or numpy array.

class Flyweight(object):

    def get(self, theData, index):
        return theData[index]

    def set(self, theData, index, value):
        theData[index]= value

The class-like wrapper has no attributes — it just provides methods that act on the underlying data. The methods can be reduced to class methods. Indeed, it could be reduced to just functions operating on the underlying array of data.

What do 3 dots next to a parameter type mean in Java?

Adding to the other well-written answers, an advantage of varagrs I found useful is that, when I call a method with array as a parameter type, it takes away the pain of creating an array; add elements and then send it. Instead, I can just call the method with as many values as I want; from zero to many.

Groovy write to file (newline)

Might be cleaner to use PrintWriter and its method println.
Just make sure you close the writer when you're done

How can I stream webcam video with C#?

The usual API for this is DirectShow.

You can use P/Invoke to import the C++ APIs, but I think there are already a few projects out there that have done this.

To get the streaming part, you probably want to use DirectShow to apply a compression codec to reduce lag, then you can get a Stream and transmit it. You could consider using multicast to reduce network load.

Convert seconds to Hour:Minute:Second

$time=3*3600 + 30*60;






    echo $year." year, ";
    echo $month." month, ";
    echo $day." day, ";
    echo $hour." hour, ";
    echo $minute." minute, ";
    echo $second." second, ";

Python: What OS am I running on?

Sample code to differentiate OS's using python:

from sys import platform as _platform

if _platform == "linux" or _platform == "linux2":
    # linux
elif _platform == "darwin":
    # MAC OS X
elif _platform == "win32":
    # Windows
elif _platform == "win64":
    # Windows 64-bit

Uploading images using Node.js, Express, and Mongoose

I know that the original question related to specific versions, but it also referred to the "latest" - @JohnAllen 's post is no longer relevant due to Expressjs bodyParser and connect-form

This demonstrates the easy to use in-built bodyParser():

 * Module dependencies.

var express = require('express')

var app = express()
app.use(express.bodyParser({ keepExtensions: true, uploadDir: '/home/svn/rest-api/uploaded' }))

app.get('/', function(req, res){
  res.send('<form method="post" enctype="multipart/form-data">'
    + '<p>Image: <input type="file" name="image" /></p>'
    + '<p><input type="submit" value="Upload" /></p>'
    + '</form>');
});'/', function(req, res, next){

    res.send('Uploaded: ' +
    return next()


console.log('Express app started on port 3000');

Using NSLog for debugging

Why do you have the brackets around digit? It should be

NSLog("%@", digit);

You're also missing an = in the first line...

NSString *digit = [[sender titlelabel] text];

How to convert Blob to File in JavaScript

You can use the File constructor:

var file = new File([myBlob], "name");

As per the w3 specification this will append the bytes that the blob contains to the bytes for the new File object, and create the file with the specified name

Using NULL in C++?

Assuming that you don't have a library or system header that defines NULL as for example (void*)0 or (char*)0 it's fine. I always tend to use 0 myself as it is by definition the null pointer. In c++0x you'll have nullptr available so the question won't matter as much anymore.

Maximum execution time in phpMyadmin

For Xampp version on Windows

Add this line to xampp\phpmyadmin\

$cfg['ExecTimeLimit'] = 6000;

And Change xampp\php\php.ini to

post_max_size = 750M 
upload_max_filesize = 750M   
max_execution_time = 5000
max_input_time = 5000
memory_limit = 1000M

And change xampp\mysql\bin\my.ini

max_allowed_packet = 200M

Standard Android Button with a different color

I like the color filter suggestion in previous answers from @conjugatedirection and @Tomasz; However, I found that the code provided so far wasn't as easily applied as I expected.

First, it wasn't mentioned where to apply and clear the color filter. It's possible that there are other good places to do this, but what came to mind for me was an OnTouchListener.

From my reading of the original question, the ideal solution would be one that does not involve any images. The accepted answer using custom_button.xml from @emmby is probably a better fit than color filters if that's your goal. In my case, I'm starting with a png image from a UI designer of what the button is supposed to look like. If I set the button background to this image, the default highlight feedback is lost completely. This code replaces that behavior with a programmatic darkening effect.

button.setOnTouchListener(new OnTouchListener() {
    public boolean onTouch(View v, MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                // 0x6D6D6D sets how much to darken - tweak as desired
                setColorFilter(v, 0x6D6D6D);
            // remove the filter when moving off the button
            // the same way a selector implementation would 
            case MotionEvent.ACTION_MOVE:
                Rect r = new Rect();
                if (!r.contains((int) event.getX(), (int) event.getY())) {
                    setColorFilter(v, null);
            case MotionEvent.ACTION_OUTSIDE:
            case MotionEvent.ACTION_CANCEL:
            case MotionEvent.ACTION_UP:
                setColorFilter(v, null);
        return false;

    private void setColorFilter(View v, Integer filter) {
        if (filter == null) v.getBackground().clearColorFilter();
        else {
            // To lighten instead of darken, try this:
            // LightingColorFilter lighten = new LightingColorFilter(0xFFFFFF, filter);
            LightingColorFilter darken = new LightingColorFilter(filter, 0x000000);
        // required on Android 2.3.7 for filter change to take effect (but not on 4.0.4)

I extracted this as a separate class for application to multiple buttons - shown as anonymous inner class just to get the idea.

The target ... overrides the `OTHER_LDFLAGS` build setting defined in `Pods/Pods.xcconfig

If Xcode complains when linking, e.g. Library not found for -lPods, it doesn't detect the implicit dependencies:

Go to Product > Edit Scheme Click on Build Add the Pods static library Clean and build again

Difference between database and schema

Schema says what tables are in database, what columns they have and how they are related. Each database has its own schema.

Set proxy through windows command line including login parameters

If you are using Microsoft windows environment then you can set a variable named HTTP_PROXY, FTP_PROXY, or HTTPS_PROXY depending on the requirement.

I have used following settings for allowing my commands at windows command prompt to use the browser proxy to access internet.

set HTTP_PROXY=http://proxy_userid:proxy_password@proxy_ip:proxy_port

The parameters on right must be replaced with actual values.

Once the variable HTTP_PROXY is set, all our subsequent commands executed at windows command prompt will be able to access internet through the proxy along with the authentication provided.

Additionally if you want to use ftp and https as well to use the same proxy then you may like to the following environment variables as well.



excel formula to subtract number of days from a date

Here is what worked for me (Excel 14.0 - aka MS Office Pro Plus 2010):

=DATE(YEAR(A1), MONTH(A1), DAY(A1) - 16)

This takes the date (format mm/dd/yyyy) in cell A1 and subtracts 16 days with output in format of mm/dd/yyyy.

HTML Best Practices: Should I use &rsquo; or the special keyboard shortcut?

If your text will be consumed by non-browsers then it's safer to type the character with the keyboard-combo option shift right bracket because &rsquo; will not be transformed into an apostrophe by a regular XML or JSON parser. (e.g. if you are serving this content to native Android/iOS apps).

JavaScript dictionary with names


var myMappings = {
    "Name":     "10%",
    "Phone":    "10%",
    "Address":  "50%",
    "Zip":      "10%",
    "Comments": "20%"

// Access is like this
myMappings["Name"] // Returns "10%"
myMappings.Name // The same thing as above

// To loop through...
for(var title in myMappings) {
    // Do whatever with myMappings[title]

Deserializing JSON to .NET object using Newtonsoft (or LINQ to JSON maybe?)

With the dynamic keyword, it becomes really easy to parse any object of this kind:

dynamic x = Newtonsoft.Json.JsonConvert.DeserializeObject(jsonString);
var page =;
var total_pages = x.total_pages
var albums = x.albums;
foreach(var album in albums)
    var albumName =;

    // Access album data;

Combining multiple condition in single case statement in Sql Server

select ROUND(CASE 

WHEN  CONVERT( float, REPLACE( isnull( value1,''),',',''))='' AND CONVERT( float, REPLACE( isnull( value2,''),',',''))='' then  CONVERT( float, REPLACE( isnull( value3,''),',',''))

WHEN  CONVERT( float, REPLACE( isnull( value1,''),',',''))='' AND CONVERT( float, REPLACE( isnull( value2,''),',',''))!='' then  CONVERT( float, REPLACE( isnull( value3,''),',',''))

WHEN  CONVERT( float, REPLACE( isnull( value1,''),',',''))!='' AND CONVERT( float, REPLACE( isnull( value2,''),',',''))='' then  CONVERT( float, REPLACE( isnull( value3,''),',',''))

else CONVERT( float, REPLACE(isnull( value1,''),',','')) end,0)  from Tablename where    ID="123" 

How to insert new cell into UITableView in Swift

Here is your code for add data into both tableView:

import UIKit

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

    @IBOutlet weak var table1Text: UITextField!
    @IBOutlet weak var table2Text: UITextField!
    @IBOutlet weak var table1: UITableView!
    @IBOutlet weak var table2: UITableView!

    var table1Data = ["a"]
    var table2Data = ["1"]

    override func viewDidLoad() {


    @IBAction func addData(sender: AnyObject) {

        //add your data into tables array from textField

        dispatch_async(dispatch_get_main_queue(), { () -> Void in
            //reload your tableView


    //delegate methods
    func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return 1
    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if tableView == table1 {
            return table1Data.count
        }else if tableView == table2 {
            return table2Data.count
        return Int()

    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

        if tableView == table1 {
            let cell = table1.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! UITableViewCell

            let row = indexPath.row
            cell.textLabel?.text = table1Data[row]

            return cell
        }else if tableView == table2 {

            let cell = table2.dequeueReusableCellWithIdentifier("Cell1", forIndexPath: indexPath) as! UITableViewCell

            let row = indexPath.row
            cell.textLabel?.text = table2Data[row]

            return cell

        return UITableViewCell()

And your result will be:

enter image description here

How to serialize an object to XML without getting xmlns="..."?

I Suggest this helper class:

public static class Xml
    #region Fields

    private static readonly XmlWriterSettings WriterSettings = new XmlWriterSettings {OmitXmlDeclaration = true, Indent = true};
    private static readonly XmlSerializerNamespaces Namespaces = new XmlSerializerNamespaces(new[] {new XmlQualifiedName("", "")});


    #region Methods

    public static string Serialize(object obj)
        if (obj == null)
            return null;

        return DoSerialize(obj);

    private static string DoSerialize(object obj)
        using (var ms = new MemoryStream())
        using (var writer = XmlWriter.Create(ms, WriterSettings))
            var serializer = new XmlSerializer(obj.GetType());
            serializer.Serialize(writer, obj, Namespaces);
            return Encoding.UTF8.GetString(ms.ToArray());

    public static T Deserialize<T>(string data)
        where T : class
        if (string.IsNullOrEmpty(data))
            return null;

        return DoDeserialize<T>(data);

    private static T DoDeserialize<T>(string data) where T : class
        using (var ms = new MemoryStream(Encoding.UTF8.GetBytes(data)))
            var serializer = new XmlSerializer(typeof (T));
            return (T) serializer.Deserialize(ms);



Is it possible to focus on a <div> using JavaScript focus() function?

<div id="inner" tabindex="0">
    this div can now have focus and receive keyboard events

WELD-001408: Unsatisfied dependencies for type Customer with qualifiers @Default

Your Customer class has to be discovered by CDI as a bean. For that you have two options:

  1. Put a bean defining annotation on it. As @Model is a stereotype it's why it does the trick. A qualifier like @Named is not a bean defining annotation, reason why it doesn't work

  2. Change the bean discovery mode in your bean archive from the default "annotated" to "all" by adding a beans.xml file in your jar.

Keep in mind that @Named has only one usage : expose your bean to the UI. Other usages are for bad practice or compatibility with legacy framework.

Python 3.4.0 with MySQL database

There is a Ubuntu solution available either through the Ubuntu Software Center or through the Synaptic Package Manager. This will connect Python version 3.4.0 to MySQL. Download "python3-mysql.connector" version 1.1.6-1.

Note that the connection syntax does not use "MySQLdb". Instead read: Connecting to MySQL Using Connector/Python

Manually put files to Android emulator SD card

Use the adb tool that comes with the SDK.

adb push myDirectory /sdcard/targetDir

If you only specify /sdcard/ (with the trailing slash) as destination, then the CONTENTS of myDirectory will end up in the root of /sdcard.

jQuery hide and show toggle div with plus and minus icon

Toggle the text Show and Hide and move your backgroundPosition Y axis


$(function(){ // DOM READY shorthand


    $('.show_hide').click(function( e ){
        // e.preventDefault(); // If you use anchors
        var SH = this.SH^=1; // "Simple toggler"
               .css({backgroundPosition:'0 '+ (SH?-18:0) +'px'})



  background:url(plusminus.png) no-repeat;

Setting Curl's Timeout in PHP

There is a quirk with this that might be relevant for some people... From the PHP docs comments.

If you want cURL to timeout in less than one second, you can use CURLOPT_TIMEOUT_MS, although there is a bug/"feature" on "Unix-like systems" that causes libcurl to timeout immediately if the value is < 1000 ms with the error "cURL Error (28): Timeout was reached". The explanation for this behavior is:

"If libcurl is built to use the standard system name resolver, that portion of the transfer will still use full-second resolution for timeouts with a minimum timeout allowed of one second."

What this means to PHP developers is "You can't use this function without testing it first, because you can't tell if libcurl is using the standard system name resolver (but you can be pretty sure it is)"

The problem is that on (Li|U)nix, when libcurl uses the standard name resolver, a SIGALRM is raised during name resolution which libcurl thinks is the timeout alarm.

The solution is to disable signals using CURLOPT_NOSIGNAL. Here's an example script that requests itself causing a 10-second delay so you can test timeouts:

if (!isset($_GET['foo'])) {
    // Client
    $ch = curl_init('http://localhost/test/test_timeout.php?foo=bar');
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_NOSIGNAL, 1);
    curl_setopt($ch, CURLOPT_TIMEOUT_MS, 200);
    $data = curl_exec($ch);
    $curl_errno = curl_errno($ch);
    $curl_error = curl_error($ch);

    if ($curl_errno > 0) {
        echo "cURL Error ($curl_errno): $curl_error\n";
    } else {
        echo "Data received: $data\n";
} else {
    // Server
    echo "Done.";


How to check if string contains Latin characters only?

There is no jquery needed:

var matchedPosition =[a-z]/i);
if(matchedPosition != -1) {

One-liner if statements, how to convert this if-else-statement

return (expression) ? value1 : value2;

If value1 and value2 are actually true and false like in your example, you may as well just

return expression;

What does $(function() {} ); do?

$(function() { ... });

is just jQuery short-hand for

$(document).ready(function() { ... });

What it's designed to do (amongst other things) is ensure that your function is called once all the DOM elements of the page are ready to be used.

However, I don't think that's the problem you're having - can you clarify what you mean by 'Somehow, some functions are cannot be called and I have to call those function inside' ? Maybe post some code to show what's not working as expected ?

Edit: Re-reading your question, it could be that your function is running before the page has finished loaded, and therefore won't execute properly; putting it in $(function) would indeed fix that!

Missing artifact com.sun:tools:jar

If this problem still happens, it might be because of a JDK of version equal or greater than 11.

The tools.jar archive has been removed from the lib folder in those JDK's (see this answer to a similar question). In that case, try to use other versions of the libraries, that do not rely on the com.sun:tools library.

Free easy way to draw graphs and charts in C++?

My favourite has always been gnuplot. It's very extensive, so it might be a bit too complex for your needs though. It is cross-platform and there is a C++ API.

Grant execute permission for a user on all stored procedures in database?

Create a role add this role to users, and then you can grant execute to all the routines in one shot to this role.


This works in SQL Server 2005, I'm not sure about backward compatibility of this feature, I'm sure anything later than 2005 should be fine.

How to center a View inside of an Android Layout?

Use ConstraintLayout. Here is an example that will center the view according to the width and height of the parent screen:

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

    <LinearLayout xmlns:android=""

You might need to change your gradle to get the latest version of ConstraintLayout:

dependencies {
    implementation ''

enter image description here

Java - Reading XML file

Avoid hardcoding try making the code that is dynamic below is the code it will work for any xml I have used SAX Parser you can use dom,xpath it's upto you I am storing all the tags name and values in the map after that it becomes easy to retrieve any values you want I hope this helps

<child >
    <child1> value 1 </child1>
    <child2> value 2 </child2>
    <child3> value 3 </child3>
    <child >
     <child4> value 4 </child4>
    <child5> value 5</child5>
    <child6> value 6 </child6>


    import java.util.HashMap;
    import java.util.LinkedHashMap;
    import java.util.Map;
    import javax.xml.parsers.ParserConfigurationException;
    import javax.xml.parsers.SAXParser;
    import javax.xml.parsers.SAXParserFactory;
    import org.xml.sax.Attributes;
    import org.xml.sax.SAXException;
    import org.xml.sax.helpers.DefaultHandler;

    public class saxParser {
           static Map<String,String> tmpAtrb=null;
           static Map<String,String> xmlVal= new LinkedHashMap<String, String>();
        public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException, VerifyError {

             * We can pass the class name of the XML parser
             * to the SAXParserFactory.newInstance().

            //SAXParserFactory saxDoc = SAXParserFactory.newInstance("", null);

            SAXParserFactory saxDoc = SAXParserFactory.newInstance();
            SAXParser saxParser = saxDoc.newSAXParser();

            DefaultHandler handler = new DefaultHandler() {
                String tmpElementName = null;
                String tmpElementValue = null;

                public void startElement(String uri, String localName, String qName, 
                                                                    Attributes attributes) throws SAXException {
                    tmpElementValue = "";
                    tmpElementName = qName;
                    tmpAtrb=new HashMap();
                    //System.out.println("Start Element :" + qName);
                     * Store attributes in HashMap
                    for (int i=0; i<attributes.getLength(); i++) {
                        String aname = attributes.getLocalName(i);
                        String value = attributes.getValue(i);
                        tmpAtrb.put(aname, value);


                public void endElement(String uri, String localName, String qName) 
                                                            throws SAXException { 

                        System.out.println("Element Name :"+tmpElementName);
                     * Retrive attributes from HashMap
                     */                    for (Map.Entry<String, String> entrySet : tmpAtrb.entrySet()) {
                            System.out.println("Attribute Name :"+ entrySet.getKey() + "Attribute Value :"+ entrySet.getValue());
                        System.out.println("Element Value :"+tmpElementValue);
                        xmlVal.put(tmpElementName, tmpElementValue);
                      //Fetching The Values From The Map
                        String getKeyValues=xmlVal.get(tmpElementName);
                public void characters(char ch[], int start, int length) throws SAXException {
                    tmpElementValue = new String(ch, start, length) ;  
             * Below two line used if we use SAX 2.0
             * Then last line not needed.

            //saxParser.parse(new InputSource("c:/file.xml"));
            saxParser.parse(new File("D:/Test _ XML/file.xml"), handler);


Element Name :child1
Element Value : value 1 
XmlTag:<child1>:::::ValueFetchedFromTheMap: value 1 
Element Name :child2
Element Value : value 2 
XmlTag:<child2>:::::ValueFetchedFromTheMap: value 2 
Element Name :child3
Element Value : value 3 
XmlTag:<child3>:::::ValueFetchedFromTheMap: value 3 
Element Name :child4
Element Value : value 4 
XmlTag:<child4>:::::ValueFetchedFromTheMap: value 4 
Element Name :child5
Element Value : value 5
XmlTag:<child5>:::::ValueFetchedFromTheMap: value 5
Element Name :child6
Element Value : value 6 
XmlTag:<child6>:::::ValueFetchedFromTheMap: value 6 
Values Inside The Map:{child1= value 1 , child2= value 2 , child3= value 3 , child4= value 4 , child5= value 5, child6= value 6 }

PHP Fatal error: Class 'PDO' not found

Try adding use PDO; after your namespace or just before your class or at the top of your PHP file.

Declaring variables inside or outside of a loop

Please skip to the updated answer...

For those who care about performance take out the System.out and limit the loop to 1 byte. Using double (test 1/2) and using String (3/4) the elapsed times in milliseconds is given below with Windows 7 Professional 64 bit and JDK-1.7.0_21. Bytecodes (also given below for test1 and test2) are not the same. I was too lazy to test with mutable & relatively complex objects.


Test1 took: 2710 msecs

Test2 took: 2790 msecs

String (just replace double with string in the tests)

Test3 took: 1200 msecs

Test4 took: 3000 msecs

Compiling and getting bytecode


javap.exe -c LocalTest1 > LocalTest1.bc

public class LocalTest1 {

    public static void main(String[] args) throws Exception {
        long start = System.currentTimeMillis();
        double test;
        for (double i = 0; i < 1000000000; i++) {
            test = i;
        long finish = System.currentTimeMillis();
        System.out.println("Test1 Took: " + (finish - start) + " msecs");


public class LocalTest2 {

    public static void main(String[] args) throws Exception {
        long start = System.currentTimeMillis();
        for (double i = 0; i < 1000000000; i++) {
            double test = i;
        long finish = System.currentTimeMillis();
        System.out.println("Test1 Took: " + (finish - start) + " msecs");

Compiled from ""
public class LocalTest1 {
  public LocalTest1();
       0: aload_0
       1: invokespecial #1                  // Method java/lang/Object."<init>":()V
       4: return

  public static void main(java.lang.String[]) throws java.lang.Exception;
       0: invokestatic  #2                  // Method java/lang/System.currentTimeMillis:()J
       3: lstore_1
       4: dconst_0
       5: dstore        5
       7: dload         5
       9: ldc2_w        #3                  // double 1.0E9d
      12: dcmpg
      13: ifge          28
      16: dload         5
      18: dstore_3
      19: dload         5
      21: dconst_1
      22: dadd
      23: dstore        5
      25: goto          7
      28: invokestatic  #2                  // Method java/lang/System.currentTimeMillis:()J
      31: lstore        5
      33: getstatic     #5                  // Field java/lang/System.out:Ljava/io/PrintStream;
      36: new           #6                  // class java/lang/StringBuilder
      39: dup
      40: invokespecial #7                  // Method java/lang/StringBuilder."<init>":()V
      43: ldc           #8                  // String Test1 Took:
      45: invokevirtual #9                  // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      48: lload         5
      50: lload_1
      51: lsub
      52: invokevirtual #10                 // Method java/lang/StringBuilder.append:(J)Ljava/lang/StringBuilder;
      55: ldc           #11                 // String  msecs
      57: invokevirtual #9                  // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      60: invokevirtual #12                 // Method java/lang/StringBuilder.toString:()Ljava/lang/String;
      63: invokevirtual #13                 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
      66: return

Compiled from ""
public class LocalTest2 {
  public LocalTest2();
       0: aload_0
       1: invokespecial #1                  // Method java/lang/Object."<init>":()V
       4: return

  public static void main(java.lang.String[]) throws java.lang.Exception;
       0: invokestatic  #2                  // Method java/lang/System.currentTimeMillis:()J
       3: lstore_1
       4: dconst_0
       5: dstore_3
       6: dload_3
       7: ldc2_w        #3                  // double 1.0E9d
      10: dcmpg
      11: ifge          24
      14: dload_3
      15: dstore        5
      17: dload_3
      18: dconst_1
      19: dadd
      20: dstore_3
      21: goto          6
      24: invokestatic  #2                  // Method java/lang/System.currentTimeMillis:()J
      27: lstore_3
      28: getstatic     #5                  // Field java/lang/System.out:Ljava/io/PrintStream;
      31: new           #6                  // class java/lang/StringBuilder
      34: dup
      35: invokespecial #7                  // Method java/lang/StringBuilder."<init>":()V
      38: ldc           #8                  // String Test1 Took:
      40: invokevirtual #9                  // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      43: lload_3
      44: lload_1
      45: lsub
      46: invokevirtual #10                 // Method java/lang/StringBuilder.append:(J)Ljava/lang/StringBuilder;
      49: ldc           #11                 // String  msecs
      51: invokevirtual #9                  // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      54: invokevirtual #12                 // Method java/lang/StringBuilder.toString:()Ljava/lang/String;
      57: invokevirtual #13                 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
      60: return


It's really not easy to compare performance with all the JVM optimizations. However, it is somewhat possible. Better test and detailed results in Google Caliper

  1. Some details on blog:Should you declare a variable inside a loop or before the loop?
  2. GitHub repository:
  3. Test Results for double case and 100M loop (and yes all JVM details):

DeclaredBefore 1,759.209 DeclaredInside 2,242.308

  • DeclaredBefore 1,759.209 ns
  • DeclaredInside 2,242.308 ns

Partial Test Code for double Declaration

This is not identical to the code above. If you just code a dummy loop JVM skips it, so at least you need to assign and return something. This is also recommended in Caliper documentation.

@Param int size; // Set automatically by framework, provided in the Main
* Variable is declared inside the loop.
* @param reps
* @return
public double timeDeclaredInside(int reps) {
    /* Dummy variable needed to workaround smart JVM */
    double dummy = 0;

    /* Test loop */
    for (double i = 0; i <= size; i++) {

        /* Declaration and assignment */
        double test = i;

        /* Dummy assignment to fake JVM */
        if(i == size) {
            dummy = test;
    return dummy;

* Variable is declared before the loop.
* @param reps
* @return
public double timeDeclaredBefore(int reps) {

    /* Dummy variable needed to workaround smart JVM */
    double dummy = 0;

    /* Actual test variable */
    double test = 0;

    /* Test loop */
    for (double i = 0; i <= size; i++) {

        /* Assignment */
        test = i;

        /* Not actually needed here, but we need consistent performance results */
        if(i == size) {
            dummy = test;
    return dummy;

Summary: declaredBefore indicates better performance -really tiny- and it's against the smallest scope principle. JVM should actually do this for you

Bitwise operation and usage

Whilst manipulating bits of an integer is useful, often for network protocols, which may be specified down to the bit, one can require manipulation of longer byte sequences (which aren't easily converted into one integer). In this case it is useful to employ the bitstring library which allows for bitwise operations on data - e.g. one can import the string 'ABCDEFGHIJKLMNOPQ' as a string or as hex and bit shift it (or perform other bitwise operations):

>>> import bitstring
>>> bitstring.BitArray(bytes='ABCDEFGHIJKLMNOPQ') << 4
>>> bitstring.BitArray(hex='0x4142434445464748494a4b4c4d4e4f5051') << 4

Converting milliseconds to a date (jQuery/JavaScript)

use datejs

new Date().toString('yyyy-MM-d-h-mm-ss');

How can I find the version of the Fedora I use?

On my installation of Fedora 25 (workstation) all of the distribution ID info was found in this file:


This included,

  • NAME=Fedora
  • VERSION="25 (Workstation Edition)"
  • ID=fedora
  • PRETTY_NAME="Fedora 25 (Workstation Edition)"
  • <...>
  • VARIANT="Workstation Edition"
  • VARIANT_ID=workstation

Git - how delete file from remote repository

Use commands :

git rm /path to file name /

followed by

git commit -m "Your Comment"

git push

your files will get deleted from the repository

How to convert object to Dictionary<TKey, TValue> in C#?

    public static KeyValuePair<object, object > Cast<K, V>(this KeyValuePair<K, V> kvp)
        return new KeyValuePair<object, object>(kvp.Key, kvp.Value);

    public static KeyValuePair<T, V> CastFrom<T, V>(Object obj)
        return (KeyValuePair<T, V>) obj;

    public static KeyValuePair<object , object > CastFrom(Object obj)
        var type = obj.GetType();
        if (type.IsGenericType)
            if (type == typeof (KeyValuePair<,>))
                var key = type.GetProperty("Key");
                var value = type.GetProperty("Value");
                var keyObj = key.GetValue(obj, null);
                var valueObj = value.GetValue(obj, null);
                return new KeyValuePair<object, object>(keyObj, valueObj);
        throw new ArgumentException(" ### -> public static KeyValuePair<object , object > CastFrom(Object obj) : Error : obj argument must be KeyValuePair<,>");

From the OP:

Instead of converting my whole Dictionary, i decided to keep my obj dynamic the whole time. When i access the keys and values of my Dictionary with a foreach later, i use foreach(dynamic key in obj.Keys) and convert the keys and values to strings simply.

Can I call a base class's virtual function if I'm overriding it?

Sometimes you need to call the base class' implementation, when you aren't in the derived function...It still works:

struct Base
    virtual int Foo()
        return -1;

struct Derived : public Base
    virtual int Foo()
        return -2;

int main(int argc, char* argv[])
    Base *x = new Derived;

    ASSERT(-2 == x->Foo());

    //syntax is trippy but it works
    ASSERT(-1 == x->Base::Foo());

    return 0;

How to activate "Share" button in android app?

in kotlin :

val sharingIntent = Intent(android.content.Intent.ACTION_SEND)
sharingIntent.type = "text/plain"
val shareBody = "Application Link :${App.context.getPackageName()}"
sharingIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, "App link")
sharingIntent.putExtra(android.content.Intent.EXTRA_TEXT, shareBody)
startActivity(Intent.createChooser(sharingIntent, "Share App Link Via :"))

How to check if a table is locked in sql server

sys.dm_tran_locks contains the locking information of the sessions

If you want to know a specific table is locked or not, you can use the following query

  resource_associated_entity_id = object_id('schemaname.tablename')

if you are interested in finding both login name of the user and the query being run

 , s.original_login_name
 , s.status
 , s.program_name
 , s.host_name
 , (select text from sys.dm_exec_sql_text(exrequests.sql_handle))
  sys.dm_tran_locks dbl
     JOIN sys.dm_exec_sessions s ON dbl.request_session_id = s.session_id
  INNER JOIN  sys.dm_exec_requests exrequests on dbl.request_session_id = exrequests.session_id
 DB_NAME(dbl.resource_database_id) = 'dbname'

For more infomraton locking query

More infor about sys.dm_tran_locks

Read and write to binary files in C?

Reading and writing binary files is pretty much the same as any other file, the only difference is how you open it:

unsigned char buffer[10];
FILE *ptr;

ptr = fopen("test.bin","rb");  // r for read, b for binary

fread(buffer,sizeof(buffer),1,ptr); // read 10 bytes to our buffer

You said you can read it, but it's not outputting correctly... keep in mind that when you "output" this data, you're not reading ASCII, so it's not like printing a string to the screen:

for(int i = 0; i<10; i++)
    printf("%u ", buffer[i]); // prints a series of bytes

Writing to a file is pretty much the same, with the exception that you're using fwrite() instead of fread():

FILE *write_ptr;

write_ptr = fopen("test.bin","wb");  // w for write, b for binary

fwrite(buffer,sizeof(buffer),1,write_ptr); // write 10 bytes from our buffer

Since we're talking Linux.. there's an easy way to do a sanity check. Install hexdump on your system (if it's not already on there) and dump your file:

mike@mike-VirtualBox:~/C$ hexdump test.bin
0000000 457f 464c 0102 0001 0000 0000 0000 0000
0000010 0001 003e 0001 0000 0000 0000 0000 0000

Now compare that to your output:

mike@mike-VirtualBox:~/C$ ./a.out 
127 69 76 70 2 1 1 0 0 0

hmm, maybe change the printf to a %x to make this a little clearer:

mike@mike-VirtualBox:~/C$ ./a.out 
7F 45 4C 46 2 1 1 0 0 0

Hey, look! The data matches up now*. Awesome, we must be reading the binary file correctly!

*Note the bytes are just swapped on the output but that data is correct, you can adjust for this sort of thing

How to import classes defined in

Yes, it is possible. You might also want to define __all__ in files. It's a list of modules that will be imported when you do

from lib import *

Plotting two variables as lines using ggplot2 on the same graph

Using your data:

test_data <- data.frame(
var0 = 100 + c(0, cumsum(runif(49, -20, 20))),
var1 = 150 + c(0, cumsum(runif(49, -10, 10))),
Dates = seq.Date(as.Date("2002-01-01"), by="1 month", length.out=100))

I create a stacked version which is what ggplot() would like to work with:

stacked <- with(test_data,
                data.frame(value = c(var0, var1),
                           variable = factor(rep(c("Var0","Var1"),
                                                 each = NROW(test_data))),
                           Dates = rep(Dates, 2)))

In this case producing stacked was quite easy as we only had to do a couple of manipulations, but reshape() and the reshape and reshape2 might be useful if you have a more complex real data set to manipulate.

Once the data are in this stacked form, it only requires a simple ggplot() call to produce the plot you wanted with all the extras (one reason why higher-level plotting packages like lattice and ggplot2 are so useful):

p <- ggplot(stacked, aes(Dates, value, colour = variable))
p + geom_line()

I'll leave it to you to tidy up the axis labels, legend title etc.


How to drop a PostgreSQL database if there are active connections to it?

PostgreSQL 9.2 and above:

SELECT pg_terminate_backend(pid)FROM pg_stat_activity WHERE datname = 'YOUR_DATABASE_NAME_HERE'

decimal vs double! - Which one should I use and when?

For money: decimal. It costs a little more memory, but doesn't have rounding troubles like double sometimes has.

Difference between "read commited" and "repeatable read"

Old question which has an accepted answer already, but I like to think of these two isolation levels in terms of how they change the locking behavior in SQL Server. This might be helpful for those who are debugging deadlocks like I was.


Shared locks are taken in the SELECT and then released when the SELECT statement completes. This is how the system can guarantee that there are no dirty reads of uncommitted data. Other transactions can still change the underlying rows after your SELECT completes and before your transaction completes.


Shared locks are taken in the SELECT and then released only after the transaction completes. This is how the system can guarantee that the values you read will not change during the transaction (because they remain locked until the transaction finishes).

How to create war files

Simplistic Shell code for creating WAR files from a standard Eclipse dynamic Web Project. Uses RAM File system (/dev/shm) on a Linux platform.


UTILITY=$(basename $0)

if [ -z "$1" ] ; then
    echo "usage: $UTILITY [-s] <web-app-directory>..."
    echo "       -s ..... With source"
    exit 1

if [ "$1" == "-s" ] ; then

while [ ! -z "$1" ] ; do


    if [ ! -d $WEB_APP_DIR ] ; then
        echo "\"$WEB_APP_DIR\" is not a directory"

    if [ ! -d $WEB_APP_DIR/WebContent ] ; then
        echo "\"$WEB_APP_DIR\" is not a Web Application directory"


    mkdir $TMP_DIR

    pushd $WEB_APP_DIR > /dev/null
    cp -r WebContent/* $TMP_DIR
    cp -r build/* $TMP_DIR/WEB-INF
    [ ! -z "$WITH_SOURCE" ] && cp -r src/* $TMP_DIR/WEB-INF/classes
    cd $TMP_DIR > /dev/null
    [ -e $WAR_FILE ] && rm -f $WAR_FILE
    jar cf $WAR_FILE .
    ls -lsF $WAR_FILE
    popd > /dev/null

    rm -rf $TMP_DIR

Split string on whitespace in Python

import re
s = "many   fancy word \nhello    \thi"
re.split('\s+', s)

How do I restart my C# WinForm Application?

I wanted the new application start up after the old one shuts down.

Using process.WaitForExit() to wait for your own process to shutdown makes no sense. It will always time out.

So, my approach is to use Application.Exit() then wait, but allow events to be processed, for a period of time. Then start a new application with the same arguments as the old.

static void restartApp() {
    string commandLineArgs = getCommandLineArgs();
    string exePath = Application.ExecutablePath;
    try {
        wait_allowingEvents( 1000 );
    } catch( ArgumentException ex ) {
    Process.Start( exePath, commandLineArgs );

static string getCommandLineArgs() {
    Queue<string> args = new Queue<string>( Environment.GetCommandLineArgs() );
    args.Dequeue(); // args[0] is always exe path/filename
    return string.Join( " ", args.ToArray() );

static void wait_allowingEvents( int durationMS ) {
    DateTime start = DateTime.Now;
    do {
    } while( start.Subtract( DateTime.Now ).TotalMilliseconds > durationMS );

iOS start Background Thread

The default sqlite library that comes with iOS is not compiled using the SQLITE_THREADSAFE macro on. This could be a reason why your code crashes.

android: changing option menu items programmatically

Try this code:

public boolean onPrepareOptionsMenu(Menu menu) {;
    return super.onPrepareOptionsMenu(menu);

public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(, menu);
    return super.onCreateOptionsMenu(menu);

public boolean onOptionsItemSelected(MenuItem item) {
    // Handle presses on the action bar items
    if (item.getItemId() == {
    }else if (item.getItemId() == {
    } else if (item.getItemId() == {
    } else if (item.getItemId() == {
    return true;

private void updateMenuItems(Menu menu){
    if (useCheckBoxAdapter && menu != null) {
    } else {

How to display raw html code in PRE or something like it but without escaping it

Cheap and cheerful answer:

<textarea>Some raw content</textarea>

The textarea will handle tabs, multiple spaces, newlines, line wrapping all verbatim. It copies and pastes nicely and its valid HTML all the way. It also allows the user to resize the code box. You don't need any CSS, JS, escaping, encoding.

You can alter the appearance and behaviour as well. Here's a monospace font, editing disabled, smaller font, no border:

    style="width:100%; font-family: Monospace; font-size:10px; border:0;"
    rows="30" disabled
>Some raw content</textarea>

This solution is probably not semantically correct. So if you need that, it might be best to choose a more sophisticated answer.

Removing multiple files from a Git repo that have already been deleted from disk

something like

git status | sed -s "s/^.*deleted: //" | xargs git rm 

may do it.

Syntax behind sorted(key=lambda: ...)

I think all of the answers here cover the core of what the lambda function does in the context of sorted() quite nicely, however I still feel like a description that leads to an intuitive understanding is lacking, so here is my two cents.

For the sake of completeness, I'll state the obvious up front: sorted() returns a list of sorted elements and if we want to sort in a particular way or if we want to sort a complex list of elements (e.g. nested lists or a list of tuples) we can invoke the key argument.

For me, the intuitive understanding of the key argument, why it has to be callable, and the use of lambda as the (anonymous) callable function to accomplish this comes in two parts.

  1. Using lamba ultimately means you don't have to write (define) an entire function, like the one sblom provided an example of. Lambda functions are created, used, and immediately destroyed - so they don't funk up your code with more code that will only ever be used once. This, as I understand it, is the core utility of the lambda function and its applications for such roles are broad. Its syntax is purely by convention, which is in essence the nature of programmatic syntax in general. Learn the syntax and be done with it.

Lambda syntax is as follows:

lambda input_variable(s): tasty one liner


In [1]: f00 = lambda x: x/2

In [2]: f00(10)
Out[2]: 5.0

In [3]: (lambda x: x/2)(10)
Out[3]: 5.0

In [4]: (lambda x, y: x / y)(10, 2)
Out[4]: 5.0

In [5]: (lambda: 'amazing lambda')() # func with no args!
Out[5]: 'amazing lambda'
  1. The idea behind the key argument is that it should take in a set of instructions that will essentially point the 'sorted()' function at those list elements which should used to sort by. When it says key=, what it really means is: As I iterate through the list one element at a time (i.e. for e in list), I'm going to pass the current element to the function I provide in the key argument and use that to create a transformed list which will inform me on the order of final sorted list.

Check it out:

mylist = [3,6,3,2,4,8,23]
sorted(mylist, key=WhatToSortBy)

Base example:


[2, 3, 3, 4, 6, 8, 23] # all numbers are in order from small to large.

Example 1:

mylist = [3,6,3,2,4,8,23]
sorted(mylist, key=lambda x: x%2==0)

[3, 3, 23, 6, 2, 4, 8] # Does this sorted result make intuitive sense to you?

Notice that my lambda function told sorted to check if (e) was even or odd before sorting.

BUT WAIT! You may (or perhaps should) be wondering two things - first, why are my odds coming before my evens (since my key value seems to be telling my sorted function to prioritize evens by using the mod operator in x%2==0). Second, why are my evens out of order? 2 comes before 6 right? By analyzing this result, we'll learn something deeper about how the sorted() 'key' argument works, especially in conjunction with the anonymous lambda function.

Firstly, you'll notice that while the odds come before the evens, the evens themselves are not sorted. Why is this?? Lets read the docs:

Key Functions Starting with Python 2.4, both list.sort() and sorted() added a key parameter to specify a function to be called on each list element prior to making comparisons.

We have to do a little bit of reading between the lines here, but what this tells us is that the sort function is only called once, and if we specify the key argument, then we sort by the value that key function points us to.

So what does the example using a modulo return? A boolean value: True == 1, False == 0. So how does sorted deal with this key? It basically transforms the original list to a sequence of 1s and 0s.

[3,6,3,2,4,8,23] becomes [0,1,0,1,1,1,0]

Now we're getting somewhere. What do you get when you sort the transformed list?


Okay, so now we know why the odds come before the evens. But the next question is: Why does the 6 still come before the 2 in my final list? Well that's easy - its because sorting only happens once! i.e. Those 1s still represent the original list values, which are in their original positions relative to each other. Since sorting only happens once, and we don't call any kind of sort function to order the original even values from low to high, those values remain in their original order relative to one another.

The final question is then this: How do I think conceptually about how the order of my boolean values get transformed back in to the original values when I print out the final sorted list?

Sorted() is a built-in method that (fun fact) uses a hybrid sorting algorithm called Timsort that combines aspects of merge sort and insertion sort. It seems clear to me that when you call it, there is a mechanic that holds these values in memory and bundles them with their boolean identity (mask) determined by (...!) the lambda function. The order is determined by their boolean identity calculated from the lambda function, but keep in mind that these sublists (of one's and zeros) are not themselves sorted by their original values. Hence, the final list, while organized by Odds and Evens, is not sorted by sublist (the evens in this case are out of order). The fact that the odds are ordered is because they were already in order by coincidence in the original list. The takeaway from all this is that when lambda does that transformation, the original order of the sublists are retained.

So how does this all relate back to the original question, and more importantly, our intuition on how we should implement sorted() with its key argument and lambda?

That lambda function can be thought of as a pointer that points to the values we need to sort by, whether its a pointer mapping a value to its boolean transformed by the lambda function, or if its a particular element in a nested list, tuple, dict, etc., again determined by the lambda function.

Lets try and predict what happens when I run the following code.

mylist = [(3, 5, 8), (6, 2, 8), ( 2, 9, 4), (6, 8, 5)]
sorted(mylist, key=lambda x: x[1])

My sorted call obviously says, "Please sort this list". The key argument makes that a little more specific by saying, for each element (x) in mylist, return index 1 of that element, then sort all of the elements of the original list 'mylist' by the sorted order of the list calculated by the lambda function. Since we have a list of tuples, we can return an indexed element from that tuple. So we get:

[(6, 2, 8), (3, 5, 8), (6, 8, 5), (2, 9, 4)]

Run that code, and you'll find that this is the order. Try indexing a list of integers and you'll find that the code breaks.

This was a long winded explanation, but I hope this helps to 'sort' your intuition on the use of lambda functions as the key argument in sorted() and beyond.

How to convert Varchar to Double in sql?

use DECIMAL() or NUMERIC() as they are fixed precision and scale numbers.

SELECT fullName, 
       CAST(totalBal as DECIMAL(9,2)) _totalBal
FROM client_info 

Ternary operators in JavaScript without an "else"

You could write

x = condition ? true : x;

So that x is unmodified when the condition is false.

This then is equivalent to

if (condition) x = true


      ? defaults.slideshowWidth = obj.find('img').width()+'px' 
      : null 

There are a couple of alternatives - I'm not saying these are better/worse - merely alternatives

Passing in null as the third parameter works because the existing value is null. If you refactor and change the condition, then there is a danger that this is no longer true. Passing in the exising value as the 2nd choice in the ternary guards against this:

!defaults.slideshowWidth = 
      ? defaults.slideshowWidth = obj.find('img').width()+'px' 
      : defaults.slideshowwidth 

Safer, but perhaps not as nice to look at, and more typing. In practice, I'd probably write

defaults.slideshowWidth = defaults.slideshowWidth 
               || obj.find('img').width()+'px'

How can I run a program from a batch file without leaving the console open after the program starts?

You can use the exit keyword. Here is an example from one of my batch files:

start myProgram.exe param1

jQuery: set selected value of dropdown list?

You can select dropdown option value by name

 if( jQuery(this).text() == 'Monday' )

How can I convert String[] to ArrayList<String>

You can do something like

MyClass[] arr = myList.toArray(new MyClass[myList.size()]);

Multiple lines of text in UILabel

Method 1:

extension UILabel {//Write this extension after close brackets of your class
    func lblFunction() {
        numberOfLines = 0
        lineBreakMode = .byWordWrapping//If you want word wraping
        lineBreakMode = .byCharWrapping//If you want character wraping

Now call simply like this

myLbl.lblFunction()//Replace your label name 


Import UIKit

class MyClassName: UIViewController {//For example this is your class. 

    override func viewDidLoad() {

        myLbl.lblFunction()//Replace your label name 


}//After close of your class write this extension.

extension UILabel {//Write this extension after close brackets of your class
    func lblFunction() {
        numberOfLines = 0
        lineBreakMode = .byWordWrapping//If you want word wraping
        lineBreakMode = .byCharWrapping//If you want character wraping

Method 2:


yourLabel.numberOfLines = 0
yourLabel.lineBreakMode = .byWordWrapping//If you want word wraping
yourLabel.lineBreakMode = .byCharWrapping//If you want character wraping

Method 3:

Through Story board

To display multiple lines set 0(Zero), this will display more than one line in your label.

If you want to display n lines, set n.

See below screen.

enter image description here

If you want to set minimum font size for label Click Autoshrink and Select Minimum Font Size option

See below screens

enter image description here

Here set minimum font size

EX: 9 (In this image)

If your label get more text at that time your label text will be shrink upto 9

enter image description here

Creating a Zoom Effect on an image on hover using CSS?

I like using a background image. I find it easier and more flexible:



#menu {
    max-width: 1200px;
    text-align: center;
    margin: auto;
.zoomimg {
    display: inline-block;
    width: 250px;
    height: 375px;
    padding: 0px 5px 0px 5px;
    background-size: 100% 100%;
    background-repeat: no-repeat;
    background-position: center center;
    transition: all .5s ease;
.zoomimg:hover {
    cursor: pointer;
    background-size: 150% 150%;
.blog {
    background-image: url(;
.music {
    background-image: url(;
.projects {
    background-image: url(;
.bio {
    background-image: url(;


<div id="menu">
    <div class="blog zoomimg"></div>
    <div class="music zoomimg"></div>
    <div class="projects zoomimg"></div>
    <div class="bio zoomimg"></div>

DEMO 2 with Overlay

Android - get children inside a View?

Here is a suggestion: you can get the ID (specified e.g. by android:id="@+id/..My Str..) which was generated by R by using its given name (e.g. My Str). A code snippet using getIdentifier() method would then be:

public int getIdAssignedByR(Context pContext, String pIdString)
    // Get the Context's Resources and Package Name
    Resources resources = pContext.getResources();
    String packageName  = pContext.getPackageName();

    // Determine the result and return it
    int result = resources.getIdentifier(pIdString, "id", packageName);
    return result;

From within an Activity, an example usage coupled with findViewById would be:

// Get the View (e.g. a TextView) which has the Layout ID of "UserInput"
int rID = getIdAssignedByR(this, "UserInput")
TextView userTextView = (TextView) findViewById(rID);

Why do we need middleware for async flow in Redux?

To use Redux-saga is the best middleware in React-redux implementation.

Ex: store.js

  import createSagaMiddleware from 'redux-saga';
  import { createStore, applyMiddleware } from 'redux';
  import allReducer from '../reducer/allReducer';
  import rootSaga from '../saga';

  const sagaMiddleware = createSagaMiddleware();
  const store = createStore(

 export default store;

And then saga.js

import {takeLatest,delay} from 'redux-saga';
import {call, put, take, select} from 'redux-saga/effects';
import { push } from 'react-router-redux';
import data from './data.json';

export function* updateLesson(){
       yield put({type:'INITIAL_DATA',payload:data}) // initial data from json
       yield* takeLatest('UPDATE_DETAIL',updateDetail) // listen to your action.js 

export function* updateDetail(action) {
       //To write store update details

export default function* rootSaga(){
    yield [

And then action.js

 export default function updateFruit(props,fruit) {
    return (

And then reducer.js

import {combineReducers} from 'redux';

const fetchInitialData = (state=[],action) => {
      case "INITIAL_DATA":
          return ({type:action.type, payload:action.payload});
     return state;
 const updateDetailsData = (state=[],action) => {
      case "INITIAL_DATA":
          return ({type:action.type, payload:action.payload});
     return state;
const allReducers =combineReducers({
export default allReducers; 

And then main.js

import React from 'react';
import ReactDOM from 'react-dom';
import App from './app/components/App.jsx';
import {Provider} from 'react-redux';
import store from './app/store';
import createRoutes from './app/routes';

const initialState = {};
const store = configureStore(initialState, browserHistory);

       <Provider store={store}>
          <App />  /*is your Component*/

try this.. is working

Xcode : Adding a project as a build dependency

Under TARGETS in your project, right-click on your project target (should be the same name as your project) and choose GET INFO, then on GENERAL tab you will see DIRECT DEPENDENCIES, simply click the [+] and select SoundCloudAPI.

Set type for function parameters?

It can easilly be done with ArgueJS:

function myFunction ()
  arguments = __({myDate: Date, myString: String});
  // do stuff

Why am I getting InputMismatchException?

Here you can see the nature of Scanner:

double nextDouble()

Returns the next token as a double. If the next token is not a float or is out of range, InputMismatchException is thrown.

Try to catch the exception

try {
    // ...
} catch (InputMismatchException e) {
    System.out.print(e.getMessage()); //try to find out specific reason.



I tried your code and there is nothing wrong with it. Your are getting that error because you must have entered String value. When I entered a numeric value, it runs without any errors. But once I entered String it throw the same Exception which you have mentioned in your question.


You have entered something, which is out of range as I have mentioned above.

I'm really wondering what you could have tried to enter. In my system, it is running perfectly without changing a single line of code. Just copy as it is and try to compile and run it.

import java.util.*;

public class Test {
    public static void main(String... args) {
        new Test().askForMarks(5);

    public void askForMarks(int student) {
        double marks[] = new double[student];
        int index = 0;
        Scanner reader = new Scanner(;
        while (index < student) {
            System.out.print("Please enter a mark (0..30): ");
            marks[index] = (double) checkValueWithin(0, 30); 

    public double checkValueWithin(int min, int max) {
        double num;
        Scanner reader = new Scanner(;
        num = reader.nextDouble();                         
        while (num < min || num > max) {                 
            System.out.print("Invalid. Re-enter number: "); 
            num = reader.nextDouble();                         

        return num;

As you said, you have tried to enter 1.0, 2.8 and etc. Please try with this code.

Note : Please enter number one by one, on separate lines. I mean, enter 2.7, press enter and then enter second number (e.g. 6.7).

Eclipse IDE: How to zoom in on text?

On Mac you can do Press 'Command' and '+' buttons to zoom in. press 'Command' and '-' buttons to zoom out.

MySql Table Insert if not exist otherwise update

Jai is correct that you should use INSERT ... ON DUPLICATE KEY UPDATE.

Note that you do not need to include datenum in the update clause since it's the unique key, so it should not change. You do need to include all of the other columns from your table. You can use the VALUES() function to make sure the proper values are used when updating the other columns.

Here is your update re-written using the proper INSERT ... ON DUPLICATE KEY UPDATE syntax for MySQL:

INSERT INTO AggregatedData (datenum,Timestamp)
VALUES ("734152.979166667","2010-01-14 23:30:00.000")

Identify duplicates in a List

This is a problem where functional techniques shine. For example, the following F# solution is both clearer and less bug prone than the best imperative Java solution (and I work daily with both Java and F#).

|> Seq.countBy id 
|> Seq.choose (fun (key,count) -> if count > 1 then Some(key) else None)

Of course, this question is about Java. So my suggestion is to adopt a library which brings functional features to Java. For example, it could be solved using my own library as follows (and there are several others out there worth looking at too):

.groupBy(new Func1<Integer,Integer>() {
    public Integer call(Integer key) {
        return key;
}).filter(new Predicate<Grouping<Integer,Integer>>() {
   public Boolean call(Grouping<Integer, Integer> grouping) {
        return grouping.getGrouping().count() > 1;
}).map(new Func1<Grouping<Integer,Integer>,Integer>() {
    public Integer call(Grouping<Integer, Integer> grouping) {
        return grouping.getKey();

Can I avoid the native fullscreen video player with HTML5 on iPhone or android?

In iOS 10 beta 4.The right code in HTML5 is

<video src="file.mp4" webkit-playsinline="true" playsinline="true">

webkit-playsinline is for iOS < 10, and playsinline is for iOS >= 10

See details via

How do I calculate power-of in C#?

You are looking for the static method Math.Pow().

how to set ul/li bullet point color?

You need to use list-style-type: to change bullet type/style and the above link has all of the options listed. As others have stated the color is changed using the color property on the ul itself

To create 'black filled' bullets, use 'disc' instead of 'circle',i.e.:


Delete commit on gitlab

Supose you have the following scenario:

* 1bd2200 (HEAD, master) another commit
* d258546 bad commit
* 0f1efa9 3rd commit
* bd8aa13 2nd commit
* 34c4f95 1st commit

Where you want to remove d258546 i.e. "bad commit".

You shall try an interactive rebase to remove it: git rebase -i 34c4f95

then your default editor will pop with something like this:

 pick bd8aa13 2nd commit
 pick 0f1efa9 3rd commit
 pick d258546 bad commit
 pick 1bd2200 another commit

 # Rebase 34c4f95..1bd2200 onto 34c4f95
 # Commands:
 #  p, pick = use commit
 #  r, reword = use commit, but edit the commit message
 #  e, edit = use commit, but stop for amending
 #  s, squash = use commit, but meld into previous commit
 #  f, fixup = like "squash", but discard this commit's log message
 #  x, exec = run command (the rest of the line) using shell
 # These lines can be re-ordered; they are executed from top to bottom.
 # If you remove a line here THAT COMMIT WILL BE LOST.
 # However, if you remove everything, the rebase will be aborted.
 # Note that empty commits are commented out

just remove the line with the commit you want to strip and save+exit the editor:

 pick bd8aa13 2nd commit
 pick 0f1efa9 3rd commit
 pick 1bd2200 another commit

git will proceed to remove this commit from your history leaving something like this (mind the hash change in the commits descendant from the removed commit):

 * 34fa994 (HEAD, master) another commit
 * 0f1efa9 3rd commit
 * bd8aa13 2nd commit
 * 34c4f95 1st commit

Now, since I suppose that you already pushed the bad commit to gitlab, you'll need to repush your graph to the repository (but with the -f option to prevent it from being rejected due to a non fastforwardeable history i.e. git push -f <your remote> <your branch>)

Please be extra careful and make sure that none coworker is already using the history containing the "bad commit" in their branches.

Alternative option:

Instead of rewrite the history, you may simply create a new commit which negates the changes introduced by your bad commit, to do this just type git revert <your bad commit hash>. This option is maybe not as clean, but is far more safe (in case you are not fully aware of what are you doing with an interactive rebase).

Excel 2010: how to use autocomplete in validation list

Building on the answer of JMax, use this formula for the dynamic named range to make the solution work for multiple rows:


How to get a file directory path from file path?

Here is a script I used for recursive trimming. Replace $1 with the directory you want, of course.

 for f in $(find . -type f -name ' *')
    DIR=$(dirname "$f")
    rename 's/^ *//' *

How do I do word Stemming or Lemmatization?

If I may quote my answer to the question StompChicken mentioned:

The core issue here is that stemming algorithms operate on a phonetic basis with no actual understanding of the language they're working with.

As they have no understanding of the language and do not run from a dictionary of terms, they have no way of recognizing and responding appropriately to irregular cases, such as "run"/"ran".

If you need to handle irregular cases, you'll need to either choose a different approach or augment your stemming with your own custom dictionary of corrections to run after the stemmer has done its thing.

Is there a way to use PhantomJS in Python?

PhantomJS recently dropped Python support altogether. However, PhantomJS now embeds Ghost Driver.

A new project has since stepped up to fill the void: You probably want to use that instead:

from ghost import Ghost
ghost = Ghost()

with ghost.start() as session:
    page, extra_resources ="")
    assert page.http_status==200 and 'jeanphix' in ghost.content

How to get a random number between a float range?

Most commonly, you'd use:

import random
random.uniform(a, b) # range [a, b) or [a, b] depending on floating-point rounding

Python provides other distributions if you need.

If you have numpy imported already, you can used its equivalent:

import numpy as np
np.random.uniform(a, b) # range [a, b)

Again, if you need another distribution, numpy provides the same distributions as python, as well as many additional ones.

How to switch from POST to GET in PHP CURL

Solved: The problem lies here:

I set POST via both _CUSTOMREQUEST and _POST and the _CUSTOMREQUEST persisted as POST while _POST switched to _HTTPGET. The Server assumed the header from _CUSTOMREQUEST to be the right one and came back with a 411.

curl_setopt($curl_handle, CURLOPT_CUSTOMREQUEST, 'POST');

jquery datatables default sort

This worked for me:

            "sort": true,
            "pageLength": 20

How do I set the maximum line length in PyCharm?

For PyCharm 4

File >> Settings >> Editor >> Code Style: Right margin (columns)

suggestion: Take a look at other options in that tab, they're very helpful

Error handling in getJSON calls

I know it's been a while since someone answerd here and the poster probably already got his answer either from here or from somewhere else. I do however think that this post will help anyone looking for a way to keep track of errors and timeouts while doing getJSON requests. Therefore below my answer to the question

The getJSON structure is as follows (found on


most people implement that using

$.getJSON(url, datatosend, function(data){
    //do something with the data

where they use the url var to provide a link to the JSON data, the datatosend as a place to add the "?callback=?" and other variables that have to be send to get the correct JSON data returned, and the success funcion as a function for processing the data.

You can however add the status and xhr variables in your success function. The status variable contains one of the following strings : "success", "notmodified", "error", "timeout", or "parsererror", and the xhr variable contains the returned XMLHttpRequest object (found on w3schools)

$.getJSON(url, datatosend, function(data, status, xhr){
    if (status == "success"){
        //do something with the data
    }else if (status == "timeout"){
        alert("Something is wrong with the connection");
    }else if (status == "error" || status == "parsererror" ){
        alert("An error occured");
        alert("datatosend did not change");

This way it is easy to keep track of timeouts and errors without having to implement a custom timeout tracker that is started once a request is done.

Hope this helps someone still looking for an answer to this question.

PHP Curl UTF-8 Charset

First method (internal function)

The best way I have tried before is to use urlencode(). Keep in mind, don't use it for the whole url; instead, use it only for the needed parts. For example, a request that has two 'text-fa' and 'text-en' fields and they contain a Persian and an English text, respectively, you might only need to encode the Persian text, not the English one.

Second Method (using cURL function)

However, there are better ways if the range of characters have to be encoded is more limited. One of these ways is using CURLOPT_ENCODING, by passing it to curl_setopt():

curl_setopt($ch, CURLOPT_ENCODING, "");

Is there a "goto" statement in bash?

This solution had the following issues:

  • Indiscriminately removes all code lines ending in a :
  • Treates label: anywhere on a line as a label

Here's a fixed (shell-check clean) version:


# GOTO for bash, based upon
function goto
 local label=$1
 cmd=$(sed -En "/^[[:space:]]*#[[:space:]]*$label:[[:space:]]*#/{:a;n;p;ba};" "$0")
 eval "$cmd"

goto "$start"  # GOTO start: by default

#start:#  Comments can occur after labels
echo start
goto end

  # skip: #  Whitespace is allowed
echo this is usually skipped

# end: #
echo end

How to create a video from images with FFmpeg?

To create frames from video:

ffmpeg\ffmpeg -i %video% test\thumb%04d.jpg -hide_banner

Optional: remove frames you don't want in output video
(more accurate than trimming video with -ss & -t)

Then create video from image/frames eg.:

ffmpeg\ffmpeg -framerate 30 -start_number 56 -i test\thumb%04d.jpg -vf format=yuv420p test/output.mp4