SyntaxFix

Programs & Examples On #Intranet

An Internet Protocol-based computer network for sharing information and services inside an organisation

Override intranet compatibility mode IE8

I had struggled with this issue and wanted to help provide a unique solution and insight.

Certain AJAX based frameworks will inject javascripts and stylesheets at the beginning of the <head> and doing this seems to prevent the well-established meta tag solution from working properly. In this case I found that directly injecting into the HTTP response header, much like Andras Csehi's answer will solve the problem.

For those of us using Java Servlets however, a good way to solve this is to use a ServletFilter.

public class EmulateFilter implements Filter {

@Override
public void destroy() {
}

@Override
public void doFilter(ServletRequest arg0, ServletResponse arg1,
        FilterChain arg2) throws IOException, ServletException {
    HttpServletResponse response = ((HttpServletResponse)arg1);
    response.addHeader("X-UA-Compatible", "IE=8");
    arg2.doFilter(arg0, arg1);
}

@Override
public void init(FilterConfig arg0) throws ServletException {
}

}

Android Respond To URL in Intent

You might need to allow different combinations of data in your intent filter to get it to work in different cases (http/ vs https/, www. vs no www., etc).

For example, I had to do the following for an app which would open when the user opened a link to Google Drive forms (www.docs.google.com/forms)

Note that path prefix is optional.

        <intent-filter>
            <action android:name="android.intent.action.VIEW" />
            <category android:name="android.intent.category.DEFAULT" />
            <category android:name="android.intent.category.BROWSABLE" />

            <data android:scheme="http" />
            <data android:scheme="https" />

            <data android:host="www.docs.google.com" />
            <data android:host="docs.google.com" />

            <data android:pathPrefix="/forms" />
        </intent-filter>

Conditional Replace Pandas

The reason your original dataframe does not update is because chained indexing may cause you to modify a copy rather than a view of your dataframe. The docs give this advice:

When setting values in a pandas object, care must be taken to avoid what is called chained indexing.

You have a few alternatives:-

loc + Boolean indexing

loc may be used for setting values and supports Boolean masks:

df.loc[df['my_channel'] > 20000, 'my_channel'] = 0

mask + Boolean indexing

You can assign to your series:

df['my_channel'] = df['my_channel'].mask(df['my_channel'] > 20000, 0)

Or you can update your series in place:

df['my_channel'].mask(df['my_channel'] > 20000, 0, inplace=True)

np.where + Boolean indexing

You can use NumPy by assigning your original series when your condition is not satisfied; however, the first two solutions are cleaner since they explicitly change only specified values.

df['my_channel'] = np.where(df['my_channel'] > 20000, 0, df['my_channel'])

Is this the right way to clean-up Fragment back stack when leaving a deeply nested stack?

As written in How to pop fragment off backstack and by LarsH here, we can pop several fragments from top down to specifical tag (together with the tagged fragment) using this method:

fragmentManager?.popBackStack ("frag", FragmentManager.POP_BACK_STACK_INCLUSIVE);

Substitute "frag" with your fragment's tag. Remember that first we should add the fragment to backstack with:

fragmentTransaction.addToBackStack("frag")

If we add fragments with addToBackStack(null), we won't pop fragments that way.

Converting between datetime and Pandas Timestamp objects

You can use the to_pydatetime method to be more explicit:

In [11]: ts = pd.Timestamp('2014-01-23 00:00:00', tz=None)

In [12]: ts.to_pydatetime()
Out[12]: datetime.datetime(2014, 1, 23, 0, 0)

It's also available on a DatetimeIndex:

In [13]: rng = pd.date_range('1/10/2011', periods=3, freq='D')

In [14]: rng.to_pydatetime()
Out[14]:
array([datetime.datetime(2011, 1, 10, 0, 0),
       datetime.datetime(2011, 1, 11, 0, 0),
       datetime.datetime(2011, 1, 12, 0, 0)], dtype=object)

Convert System.Drawing.Color to RGB and Hex Value

If you can use C#6 or higher, you can benefit from Interpolated Strings and rewrite @Ari Roth's solution like this:

C# 6 :

public static class ColorConverterExtensions
{
    public static string ToHexString(this Color c) => $"#{c.R:X2}{c.G:X2}{c.B:X2}";

    public static string ToRgbString(this Color c) => $"RGB({c.R}, {c.G}, {c.B})";
}

Also:

  • I add the keyword this to use them as extensions methods.
  • We can use the type keyword string instead of the class name.
  • We can use lambda syntax.
  • I rename them to be more explicit for my taste.

Oracle: is there a tool to trace queries, like Profiler for sql server?

 
alter system set timed_statistics=true

--or 

alter session set timed_statistics=true --if want to trace your own session

-- must be big enough:

select value from v$parameter p
where name='max_dump_file_size'

-- Find out sid and serial# of session you interested in:

 select sid, serial# from v$session
 where ...your_search_params...

--you can begin tracing with 10046 event, the fourth parameter sets the trace level(12 is the biggest):

 begin
    sys.dbms_system.set_ev(sid, serial#, 10046, 12, '');
 end;

--turn off tracing with setting zero level:

begin
   sys.dbms_system.set_ev(sid, serial#, 10046, 0, '');
end;

/*possible levels: 0 - turned off 1 - minimal level. Much like set sql_trace=true 4 - bind variables values are added to trace file 8 - waits are added 12 - both bind variable values and wait events are added */

--same if you want to trace your own session with bigger level:

alter session set events '10046 trace name context forever, level 12';

--turn off:

alter session set events '10046 trace name context off';

--file with raw trace information will be located:

 select value from v$parameter p
 where name='user_dump_dest'

--name of the file(*.trc) will contain spid:

 select p.spid from v$session s, v$process p
 where s.paddr=p.addr
 and ...your_search_params...

--also you can set the name by yourself:

alter session set tracefile_identifier='UniqueString';

--finally, use TKPROF to make trace file more readable:

C:\ORACLE\admin\databaseSID\udump>
C:\ORACLE\admin\databaseSID\udump>tkprof my_trace_file.trc output=my_file.prf
TKPROF: Release 9.2.0.1.0 - Production on Wed Sep 22 18:05:00 2004
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
C:\ORACLE\admin\databaseSID\udump>

--to view state of trace file use:

set serveroutput on size 30000;
declare
  ALevel binary_integer;
begin
  SYS.DBMS_SYSTEM.Read_Ev(10046, ALevel);
  if ALevel = 0 then
    DBMS_OUTPUT.Put_Line('sql_trace is off');
  else
    DBMS_OUTPUT.Put_Line('sql_trace is on');
  end if;
end;
/

Just kind of translated http://www.sql.ru/faq/faq_topic.aspx?fid=389 Original is fuller, but anyway this is better than what others posted IMHO

How to express a NOT IN query with ActiveRecord/Rails?

You may want to have a look at the meta_where plugin by Ernie Miller. Your SQL statement:

SELECT * FROM topics WHERE forum_id NOT IN (<@forum ids>)

...could be expressed like this:

Topic.where(:forum_id.nin => @forum_ids)

Ryan Bates of Railscasts created a nice screencast explaining MetaWhere.

Not sure if this is what you're looking for but to my eyes it certainly looks better than an embedded SQL query.

What is meant by immutable?

Immutable simply mean unchangeable or unmodifiable. Once string object is created its data or state can't be changed

Consider bellow example,

class Testimmutablestring{  
  public static void main(String args[]){  
    String s="Future";  
    s.concat(" World");//concat() method appends the string at the end  
    System.out.println(s);//will print Future because strings are immutable objects  
  }  
 }

Let's get idea considering bellow diagram,

enter image description here

In this diagram, you can see new object created as "Future World". But not change "Future".Because String is immutable. s, still refer to "Future". If you need to call "Future World",

String s="Future";  
s=s.concat(" World");  
System.out.println(s);//print Future World

Why are string objects immutable in java?

Because Java uses the concept of string literal. Suppose there are 5 reference variables, all refers to one object "Future".If one reference variable changes the value of the object, it will be affected to all the reference variables. That is why string objects are immutable in java.

Go to Matching Brace in Visual Studio?

On Spanish (Spain) keyboard with VS2012 is Ctrl + ¡ as stated by @Keith but if you use Ctrl + ¿ (typed as Ctrl + Shift + ¡) then goes to Matching Brace plus selects all the code within the two braces and then you can't go again to the other brace.

Get Enum from Description attribute

 
public static class EnumEx
{
    public static T GetValueFromDescription<T>(string description) where T : Enum
    {
        foreach(var field in typeof(T).GetFields())
        {
            if (Attribute.GetCustomAttribute(field,
            typeof(DescriptionAttribute)) is DescriptionAttribute attribute)
            {
                if (attribute.Description == description)
                    return (T)field.GetValue(null);
            }
            else
            {
                if (field.Name == description)
                    return (T)field.GetValue(null);
            }
        }

        throw new ArgumentException("Not found.", nameof(description));
        // Or return default(T);
    }
}

Usage:

var panda = EnumEx.GetValueFromDescription<Animal>("Giant Panda");

How can I get form data with JavaScript/jQuery?

Updated answer for 2014: HTML5 FormData does this

var formData = new FormData(document.querySelector('form'))

You can then post formData exactly as it is - it contains all names and values used in the form.

/etc/apt/sources.list" E212: Can't open file for writing

For me there was was quite a simple solution. I was trying to edit/create a file in a folder that didn't exist. As I was already in the folder I was trying to edit/create a file in.

i.e. pwd folder/file

and was typing 

sudo vim folder/file

and rather obviously it was looking for the folder in the folder and failing to save.

CSS How to set div height 100% minus nPx

In CSS3 you could use 

height: calc(100% - 60px);

How to get week numbers from dates?

Actually, I think you may have discovered a bug in the week(...) function, or at least an error in the documentation. Hopefully someone will jump in and explain why I am wrong.

Looking at the code:

library(lubridate)
> week
function (x) 
yday(x)%/%7 + 1
<environment: namespace:lubridate>

The documentation states:

Weeks is the number of complete seven day periods that have occured between the date and January 1st, plus one.

But since Jan 1 is the first day of the year (not the zeroth), the first "week" will be a six day period. The code should (??) be 

(yday(x)-1)%/%7 + 1

NB: You are using week(...) in the data.table package, which is the same code as lubridate::week except it coerces everything to integer rather than numeric for efficiency. So this function has the same problem (??).

How to grep and replace

Other solutions mix regex syntaxes. To use perl/PCRE patterns for both search and replace, and only process matching files, this works quite well:

grep -rlIZPi 'match1' | xargs -0r perl -pi -e 's/match2/replace/gi;'

match1 and match2 are usually identical but match1 can be simplified to remove more advanced features that are only relevant to the substitution, e.g. capturing groups.

Translation: grep recursively and list matching filenames, each separated by nul to protect any special characters; pipe any filenames to xargs which is expecting a nul-separated list; if any filenames are received, pass them to perl to perform the actual substitutions.

For case-sensitive matching, drop the i flag from grep and the i pattern modifier from the s/// expression, but not the i flag from perl itself. Remove the I flag from grep to include binary files.

Download file of any type in Asp.Net MVC using FileResult?

Phil Haack has a nice article where he created a Custom File Download Action Result class. You only need to specify the virtual path of the file and the name to be saved as.

I used it once and here's my code.

        [AcceptVerbs(HttpVerbs.Get)]
        public ActionResult Download(int fileID)
        {
            Data.LinqToSql.File file = _fileService.GetByID(fileID);

            return new DownloadResult { VirtualPath = GetVirtualPath(file.Path),
                                        FileDownloadName = file.Name };
        }

In my example i was storing the physical path of the files so i used this helper method -that i found somewhere i can't remember- to convert it to a virtual path

        private string GetVirtualPath(string physicalPath)
        {
            string rootpath = Server.MapPath("~/");

            physicalPath = physicalPath.Replace(rootpath, "");
            physicalPath = physicalPath.Replace("\\", "/");

            return "~/" + physicalPath;
        }

Here's the full class as taken from Phill Haack's article 

public class DownloadResult : ActionResult {

    public DownloadResult() {}

    public DownloadResult(string virtualPath) {
        this.VirtualPath = virtualPath;
    }

    public string VirtualPath {
        get;
        set;
    }

    public string FileDownloadName {
        get;
        set;
    }

    public override void ExecuteResult(ControllerContext context) {
        if (!String.IsNullOrEmpty(FileDownloadName)) {
            context.HttpContext.Response.AddHeader("content-disposition", 
            "attachment; filename=" + this.FileDownloadName)
        }

        string filePath = context.HttpContext.Server.MapPath(this.VirtualPath);
        context.HttpContext.Response.TransmitFile(filePath);
    }
}

How to check if AlarmManager already has an alarm set?

Im under the impression that theres no way to do this, it would be nice though.

You can achieve a similar result by having a Alarm_last_set_time recorded somewhere, and having a On_boot_starter BroadcastReciever:BOOT_COMPLETED kinda thing.

How to extract custom header value in Web API message handler?

To expand on Youssef's answer, I wrote this method based Drew's concerns about the header not existing, because I ran into this situation during unit testing.

private T GetFirstHeaderValueOrDefault<T>(string headerKey, 
   Func<HttpRequestMessage, string> defaultValue, 
   Func<string,T> valueTransform)
    {
        IEnumerable<string> headerValues;
        HttpRequestMessage message = Request ?? new HttpRequestMessage();
        if (!message.Headers.TryGetValues(headerKey, out headerValues))
            return valueTransform(defaultValue(message));
        string firstHeaderValue = headerValues.FirstOrDefault() ?? defaultValue(message);
        return valueTransform(firstHeaderValue);
    }

Here's an example usage:

GetFirstHeaderValueOrDefault("X-MyGuid", h => Guid.NewGuid().ToString(), Guid.Parse);

Also have a look at @doguhan-uluca 's answer for a more general solution.

How to determine a Python variable's type?

You may be looking for the type() built-in function.

See the examples below, but there's no "unsigned" type in Python just like Java.

Positive integer:

>>> v = 10
>>> type(v)
<type 'int'>

Large positive integer:

>>> v = 100000000000000
>>> type(v)
<type 'long'>

Negative integer:

>>> v = -10
>>> type(v)
<type 'int'>

Literal sequence of characters:

>>> v = 'hi'
>>> type(v)
<type 'str'>

Floating point integer:

>>> v = 3.14159
>>> type(v)
<type 'float'>

bootstrap 4 responsive utilities visible / hidden xs sm lg not working

Bootstrap 4 (^beta) has changed the classes for responsive hiding/showing elements. See this link for correct classes to use: http://getbootstrap.com/docs/4.0/utilities/display/#hiding-elements

how to File.listFiles in alphabetical order?

The listFiles method, with or without a filter does not guarantee any order.

It does, however, return an array, which you can sort with Arrays.sort().

File[] files = XMLDirectory.listFiles(filter_xml_files);
Arrays.sort(files);
for(File _xml_file : files) {
    ...
}

This works because File is a comparable class, which by default sorts pathnames lexicographically. If you want to sort them differently, you can define your own comparator.

If you prefer using Streams:

A more modern approach is the following. To print the names of all files in a given directory, in alphabetical order, do:

Files.list(Paths.get(dirName)).sorted().forEach(System.out::println)

Replace the System.out::println with whatever you want to do with the file names. If you want only filenames that end with "xml" just do:

Files.list(Paths.get(dirName))
    .filter(s -> s.toString().endsWith(".xml"))
    .sorted()
    .forEach(System.out::println)

Again, replace the printing with whichever processing operation you would like.

How to add an element to Array and shift indexes?

System.arraycopy is more performant but tricky to get right due to indexes calculations. Better stick with jrad answer or ArrayList if you don't have performance requirements.

public static int[] insert(
    int[] array, int elementToInsert, int index) {
  int[] result = new int[array.length + 1];
  // copies first part of the array from the start up until the index
  System.arraycopy(
      array /* src */,
      0 /* srcPos */,
      result /* dest */,
      0 /* destPos */,
      index /* length */);
  // copies second part from the index up until the end shifting by 1 to the right
  System.arraycopy(
      array /* src */,
      index /* srcPos */,
      result /* dest */,
      index + 1 /* destPos */,
      array.length - index /* length */);
  result[index] = elementToInsert;
  return result;
}

And JUnit4 test to check it works as expected.

@Test
public void shouldInsertCorrectly() {
  Assert.assertArrayEquals(
      new int[]{1, 2, 3}, insert(new int[]{1, 3}, 2, 1));
  Assert.assertArrayEquals(
      new int[]{1}, insert(new int[]{}, 1, 0));
  Assert.assertArrayEquals(
      new int[]{1, 2, 3}, insert(new int[]{2, 3}, 1, 0));
  Assert.assertArrayEquals(
      new int[]{1, 2, 3}, insert(new int[]{1, 2}, 3, 2));
}

Compiling dynamic HTML strings from database

In angular 1.2.10 the line scope.$watch(attrs.dynamic, function(html) { was returning an invalid character error because it was trying to watch the value of attrs.dynamic which was html text.

I fixed that by fetching the attribute from the scope property 

 scope: { dynamic: '=dynamic'},

My example

angular.module('app')
  .directive('dynamic', function ($compile) {
    return {
      restrict: 'A',
      replace: true,
      scope: { dynamic: '=dynamic'},
      link: function postLink(scope, element, attrs) {
        scope.$watch( 'dynamic' , function(html){
          element.html(html);
          $compile(element.contents())(scope);
        });
      }
    };
  });

Laravel Controller Subfolder routing

1) That is how you can make your app organized:

Every route file (web.php, api.php ...) is declared in a map() method, in a file 

\app\Providers\RouteServiceProvider.php

When you mapping a route file you can set a ->namespace($this->namespace) for it, you will see it there among examples.

It means that you can create more files to make your project more structured!

And set different namespaces for each of them.

But I prefer set empty string for the namespace ""

2) You can set your controllers to rout in a native php way, see the example:

Route::resource('/users', UserController::class);
Route::get('/agents', [AgentController::class, 'list'])->name('agents.list');

Now you can double click your controller names in your IDE to get there quickly and conveniently.

Getting Lat/Lng from Google marker

_x000D_
_x000D_ 
var map = new google.maps.Map(document.getElementById('map_canvas'), {_x000D_
  zoom: 10,_x000D_
  center: new google.maps.LatLng(13.103, 80.274),_x000D_
  mapTypeId: google.maps.MapTypeId.ROADMAP_x000D_
});_x000D_
_x000D_
var myMarker = new google.maps.Marker({_x000D_
  position: new google.maps.LatLng(18.103, 80.274),_x000D_
  draggable: true_x000D_
});_x000D_
_x000D_
google.maps.event.addListener(myMarker, 'dragend', function(evt) {_x000D_
  document.getElementById('current').innerHTML = '<p>Marker dropped: Current Lat: ' + evt.latLng.lat().toFixed(3) + ' Current Lng: ' + evt.latLng.lng().toFixed(3) + '</p>';_x000D_
});_x000D_
google.maps.event.addListener(myMarker, 'dragstart', function(evt) {_x000D_
  document.getElementById('current').innerHTML = '<p>Currently dragging marker...</p>';_x000D_
});_x000D_
map.setCenter(myMarker.position);_x000D_
myMarker.setMap(map);_x000D_
_x000D_
function getLocation() {_x000D_
  if (navigator.geolocation) {_x000D_
    navigator.geolocation.getCurrentPosition(showPosition);_x000D_
  } else {_x000D_
    x.innerHTML = "Geolocation is not supported by this browser.";_x000D_
  }_x000D_
}_x000D_
_x000D_
function showPosition(position) {_x000D_
  document.getElementById('current').innerHTML = '<p>Marker dropped: Current Lat: ' + position.coords.latitude + ' Current Lng: ' + position.coords.longitude + '</p>';_x000D_
  var myMarker = new google.maps.Marker({_x000D_
    position: new google.maps.LatLng(position.coords.latitude, position.coords.longitude),_x000D_
    draggable: true_x000D_
  });_x000D_
  google.maps.event.addListener(myMarker, 'dragend', function(evt) {_x000D_
    document.getElementById('current').innerHTML = '<p>Marker dropped: Current Lat: ' + evt.latLng.lat().toFixed(3) + ' Current Lng: ' + evt.latLng.lng().toFixed(3) + '</p>';_x000D_
  });_x000D_
  google.maps.event.addListener(myMarker, 'dragstart', function(evt) {_x000D_
    document.getElementById('current').innerHTML = '<p>Currently dragging marker...</p>';_x000D_
  });_x000D_
  map.setCenter(myMarker.position);_x000D_
  myMarker.setMap(map);_x000D_
}_x000D_
getLocation();
_x000D_ 
#map_canvas {_x000D_
  width: 980px;_x000D_
  height: 500px;_x000D_
}_x000D_
_x000D_
#current {_x000D_
  padding-top: 25px;_x000D_
}
_x000D_ 
<script src="http://maps.google.com/maps/api/js?sensor=false&.js"></script>_x000D_
<!DOCTYPE html>_x000D_
<html lang="en">_x000D_
_x000D_
<head>_x000D_
_x000D_
</head>_x000D_
_x000D_
<body>_x000D_
  <section>_x000D_
    <div id='map_canvas'></div>_x000D_
    <div id="current">_x000D_
      <p>Marker dropped: Current Lat:18.103 Current Lng:80.274</p>_x000D_
    </div>_x000D_
  </section>_x000D_
_x000D_
_x000D_
</body>_x000D_
_x000D_
</html>
_x000D_
_x000D_
_x000D_

The application was unable to start correctly (0xc000007b)

I experienced the same problem developing a client-server app using Microsoft Visual Studio 2012.

If you used Visual Studio to develop the app, you must make sure the new (i.e. the computer that the software was not developed on) has the appropriate Microsoft Visual C++ Redistributable Package. By appropriate, you need the right year and bit version (i.e. x86 for 32 bit and x64 for 64 bit) of the Visual C++ Redistributable Package.

The Visual C++ Redistributable Packages install run-time components that are required to run C++ applications built using Visual Studio.

Here is a link to the Visual C++ Redistributable for Visual Studio 2015 .

You can check what versions are installed by going to Control Panel -> Programs -> Programs and Features.

Here's how I got this error and fixed it:

1) I developed a 32 bit application using Visual Studio 2012 on my computer. Let's call my computer ComputerA.

2) I installed the .exe and the related files on a different computer we'll call ComputerB.

3) On ComputerB, I ran the .exe and got the error message.

4) On ComputerB, I looked at the Programs and Features and didn't see Visual C++ 2012 Redistributable (x64).

5) On ComputerB, I googled for Visual C++ 2012 Redistributable and selected and installed the x64 version.

6) On ComputerB, I ran the .exe on ComputerB and did not receive the error message.

How to compare different branches in Visual Studio Code

Update: As of November, 2020, Gitlens appears within VSCode's builtin Source Control Panel

I would recommend to use: Git Lens.

enter image description here

Working copy XXX locked and cleanup failed in SVN

One approach would be to:

  1. Copy edited items to another location.
  2. Delete the folder containing the problem path.
  3. Update the containing folder through Subversion.
  4. Copy your files back or merge changes as needed.
  5. Commit

Another option would be to delete the top level folder and check out again. Hopefully it doesn't come to that though.

change PATH permanently on Ubuntu

Try to add export PATH=$PATH:/home/me/play in ~/.bashrc file.

Difference between del, remove, and pop on lists

Many best explanations are here but I will try my best to simplify more.

Among all these methods, remove & pop are postfix while delete is prefix.

remove(): It used to remove first occurrence of element

remove(i) => first occurrence of i value

>>> a = [0, 2, 3, 2, 1, 4, 6, 5, 7]
>>> a.remove(2)   # where i = 2
>>> a
[0, 3, 2, 1, 4, 6, 5, 7]

pop(): It used to remove element if:

unspecified

pop() => from end of list

>>>a.pop()
>>>a
[0, 3, 2, 1, 4, 6, 5]

specified

pop(index) => of index

>>>a.pop(2)
>>>a
[0, 3, 1, 4, 6, 5]

WARNING: Dangerous Method Ahead

delete(): Its a prefix method.

Keep an eye on two different syntax for same method: [] and (). It possesses power to:

1.Delete index

del a[index] => used to delete index and its associated value just like pop.

>>>del a[1]
>>>a
[0, 1, 4, 6, 5]

2.Delete values in range [index 1:index N]

del a[0:3] => multiple values in range

>>>del a[0:3]
>>>a
[6, 5]

3.Last but not list, to delete whole list in one shot

del (a) => as said above.

>>>del (a)
>>>a

Hope this clarifies the confusion if any.

Counting the number of occurences of characters in a string

Try this:

import java.util.Scanner;

    /* Logic: Consider first character in the string and start counting occurrence of        
              this character in the entire string. Now add this character to a empty
              string "temp" to keep track of the already counted characters.
              Next start counting from next character and start counting the character        
              only if it is not present in the "temp" string( which means only if it is
              not counted already)
public class Counting_Occurences {

    public static void main(String[] args) {


        Scanner input=new Scanner(System.in);
        System.out.println("Enter String");
        String str=input.nextLine();

        int count=0;
        String temp=""; // An empty string to keep track of counted
                                    // characters


        for(int i=0;i<str.length();i++)
        {

            char c=str.charAt(i);  // take one character (c) in string

            for(int j=i;j<str.length();j++)
            {

                char k=str.charAt(j);  
    // take one character (c) and compare with each character (k) in the string
            // also check that character (c) is not already counted.
            // if condition passes then increment the count.
                if(c==k && temp.indexOf(c)==-1)                                                                          
                {

                    count=count+1;

                }

            }

             if(temp.indexOf(c)==-1)  // if it is not already counted
             {


            temp=temp+c; // append the character to the temp indicating
                                         // that you have already counted it.

System.out.println("Character   " + c + "   occurs   " + count + "    times");
             }  
            // reset the counter for next iteration 
              count=0;

        }


    }


}

Android ImageView's onClickListener does not work

Same Silly thing happed with me.

I just copied one activity and pasted. Defined in Manifest.

Open from MainActivity.java but I was forgot that Copied Activity is getting some params in bundle and If I don't pass any params, just finished.

So My Activity is getting started but finished at same moment.

I had written Toast and found this silly mistake. :P

Django CSRF Cookie Not Set

If you're using the HTML5 Fetch API to make POST requests as a logged in user and getting Forbidden (CSRF cookie not set.), it could be because by default fetch does not include session cookies, resulting in Django thinking you're a different user than the one who loaded the page.

You can include the session token by passing the option credentials: 'include' to fetch:

var csrftoken = getCookie('csrftoken');
var headers = new Headers();
headers.append('X-CSRFToken', csrftoken);
fetch('/api/upload', {
    method: 'POST',
    body: payload,
    headers: headers,
    credentials: 'include'
})

How to slice an array in Bash

See the Parameter Expansion section in the Bash man page. A[@] returns the contents of the array, :1:2 takes a slice of length 2, starting at index 1. 

A=( foo bar "a  b c" 42 )
B=("${A[@]:1:2}")
C=("${A[@]:1}")       # slice to the end of the array
echo "${B[@]}"        # bar a  b c
echo "${B[1]}"        # a  b c
echo "${C[@]}"        # bar a  b c 42
echo "${C[@]: -2:2}"  # a  b c 42 # The space before the - is necesssary

Note that the fact that "a b c" is one array element (and that it contains an extra space) is preserved.

Time complexity of Euclid's Algorithm

There's a great look at this on the wikipedia article.

It even has a nice plot of complexity for value pairs.

It is not O(a%b).

It is known (see article) that it will never take more steps than five times the number of digits in the smaller number. So the max number of steps grows as the number of digits (ln b). The cost of each step also grows as the number of digits, so the complexity is bound by O(ln^2 b) where b is the smaller number. That's an upper limit, and the actual time is usually less.

Difference between staticmethod and classmethod

I started learning programming language with C++ and then Java and then Python and so this question bothered me a lot as well, until I understood the simple usage of each.

Class Method: Python unlike Java and C++ doesn't have constructor overloading. And so to achieve this you could use classmethod. Following example will explain this

Let's consider we have a Person class which takes two arguments first_name and last_name and creates the instance of Person. 

class Person(object):

    def __init__(self, first_name, last_name):
        self.first_name = first_name
        self.last_name = last_name

Now, if the requirement comes where you need to create a class using a single name only, just a first_name, you can't do something like this in Python.

This will give you an error when you will try to create an object (instance).

class Person(object):

    def __init__(self, first_name, last_name):
        self.first_name = first_name
        self.last_name = last_name

    def __init__(self, first_name):
        self.first_name = first_name

However, you could achieve the same thing using @classmethod as mentioned below 

class Person(object):

    def __init__(self, first_name, last_name):
        self.first_name = first_name
        self.last_name = last_name

    @classmethod
    def get_person(cls, first_name):
        return cls(first_name, "")

Static Method: This is rather simple, it's not bound to instance or class and you can simply call that using class name.

So let's say in above example you need a validation that first_name should not exceed 20 characters, you can simply do this. 

@staticmethod  
def validate_name(name):
    return len(name) <= 20

and you could simply call using class name

Person.validate_name("Gaurang Shah")

Where does Android emulator store SQLite database?

I wrote a simple bash script, which pulls database from android device to your computer (Linux, Mac users)

filename:android_db_move.sh usage: android_db_move.sh com.example.app db_name.db

#!/bin/bash

REQUIRED_ARGS=2
ADB_PATH=/Users/Tadas/Library/sdk/platform-tools/adb
PULL_DIR="~/"

if [ $# -ne $REQUIRED_ARGS ]
    then
        echo ""
        echo "Usage:"
        echo "android_db_move.sh [package_name] [db_name]"
        echo "eg. android_db_move.sh lt.appcamp.impuls impuls.db"
        echo ""
    exit 1
fi;


echo""

cmd1="$ADB_PATH -d shell 'run-as $1 cat /data/data/$1/databases/$2 > /sdcard/$2' "
cmd2="$ADB_PATH pull /sdcard/$2 $PULL_DIR"

echo $cmd1
eval $cmd1
if [ $? -eq 0 ]
    then
    echo ".........OK"
fi;

echo $cmd2
eval $cmd2

if [ $? -eq 0 ]
    then
    echo ".........OK"
fi;

exit 0

How to write a test which expects an Error to be thrown in Jasmine?

In my case the function throwing error was async so I followed here:

await expectAsync(asyncFunction()).toBeRejected();
await expectAsync(asyncFunction()).toBeRejectedWithError(...);

How to fire a button click event from JavaScript in ASP.NET

 
$("#"+document.getElementById("<%= ButtonID.ClientID %>")).trigger("click");

Declare and assign multiple string variables at the same time

All the information is in the existing answers, but I personally wished for a concise summary, so here's an attempt at it; the commands use int variables for brevity, but they apply analogously to any type, including string.

To declare multiple variables and:

  • either: initialize them each:
int i = 0, j = 1; // declare and initialize each; `var` is NOT supported as of C# 8.0
  • or: initialize them all to the same value:
int i, j;    // *declare* first (`var` is NOT supported)
i = j = 42;  // then *initialize* 

// Single-statement alternative that is perhaps visually less obvious:
// Initialize the first variable with the desired value, then use 
// the first variable to initialize the remaining ones.
int i = 42, j = i, k = i;

What doesn't work:

  • You cannot use var in the above statements, because var only works with (a) a declaration that has an initialization value (from which the type can be inferred), and (b), as of C# 8.0, if that declaration is the only one in the statement (otherwise you'll get compilation error error CS0819: Implicitly-typed variables cannot have multiple declarators).

  • Placing an initialization value only after the last variable in a multiple-declarations statement initializes the last variable only:

    int i, j = 1;// initializes *only* j

VBA Runtime Error 1004 "Application-defined or Object-defined error" when Selecting Range

It's a bit late but might be helpful for future reference. I had just had the same issue and I think it's because the macro was placed at the worksheet level. Right click on the modules node on the VBA project window, click on "Insert" => "Module", then paste your macro in the new module (make sure you delete the one recorded at the worksheet level).

Check which element has been clicked with jQuery

So you are doing this a bit backwards. Typically you'd do something like this:

?<div class='article'>
  Article 1
</div>
<div class='article'>
  Article 2
</div>
<div class='article'>
  Article 3
</div>?

And then in your jQuery:

$('.article').click(function(){
    article = $(this).text(); //$(this) is what you clicked!
    });?

When I see things like #search-item .search-article, #search-item .search-article, and #search-item .search-article I sense you are overspecifying your CSS which makes writing concise jQuery very difficult. This should be avoided if at all possible.

MySQL "incorrect string value" error when save unicode string in Django

If it's a new project, I'd just drop the database, and create a new one with a proper charset:

CREATE DATABASE <dbname> CHARACTER SET utf8;

Implement a loading indicator for a jQuery AJAX call

I'm guessing you're using jQuery.get or some other jQuery ajax function to load the modal. You can show the indicator before the ajax call, and hide it when the ajax completes. Something like

$('#indicator').show();
$('#someModal').get(anUrl, someData, function() { $('#indicator').hide(); });

Enable/Disable a dropdownbox in jquery

try this

 <script type="text/javascript">
        $(document).ready(function () {
            $("#chkdwn2").click(function () {
                if (this.checked)
                    $('#dropdown').attr('disabled', 'disabled');
                else
                    $('#dropdown').removeAttr('disabled');
            });
        });
    </script>

convert string array to string

Like this:

string str= test[0]+test[1];

You can also use a loop:

for(int i=0; i<2; i++)
    str += test[i];

What is the meaning of "$" sign in JavaScript

Your snippet of code looks like it's referencing methods from one of the popular JavaScript libraries (jQuery, ProtoType, mooTools, and so on).

There's nothing mysterious about the use of $ in JavaScript. $ is simply a valid JavaScript identifier.

JavaScript allows upper and lower letters, numbers, and $ and _. The $ was intended to be used for machine-generated variables (such as $0001).

Prototype, jQuery, and most javascript libraries use the $ as the primary base object (or function). Most of them also have a way to relinquish the $ so that it can be used with another library that uses it. In that case you use jQuery instead of $. In fact, $ is just a shortcut for jQuery.

How to refresh datagrid in WPF

From MSDN - 

CollectionViewSource.GetDefaultView(myGrid.ItemsSource).Refresh();

Ping with timestamp on Windows CLI

Try this:

Create a batch file with the following:

echo off

cd\

:start

echo %time% >> c:\somedirectory\pinghostname.txt

ping pinghostname >> c:\somedirectory\pinghostname.txt

goto start

You can add your own options to the ping command based on your requirements. This doesn't put the time stamp on the same line as the ping, but it still gets you the info you need.

An even better way is to use fping, go here http://www.kwakkelflap.com/fping.html to download it.

Grouped bar plot in ggplot

First you need to get the counts for each category, i.e. how many Bads and Goods and so on are there for each group (Food, Music, People). This would be done like so:

raw <- read.csv("http://pastebin.com/raw.php?i=L8cEKcxS",sep=",")
raw[,2]<-factor(raw[,2],levels=c("Very Bad","Bad","Good","Very Good"),ordered=FALSE)
raw[,3]<-factor(raw[,3],levels=c("Very Bad","Bad","Good","Very Good"),ordered=FALSE)
raw[,4]<-factor(raw[,4],levels=c("Very Bad","Bad","Good","Very Good"),ordered=FALSE)

raw=raw[,c(2,3,4)] # getting rid of the "people" variable as I see no use for it

freq=table(col(raw), as.matrix(raw)) # get the counts of each factor level

Then you need to create a data frame out of it, melt it and plot it:

Names=c("Food","Music","People")     # create list of names
data=data.frame(cbind(freq),Names)   # combine them into a data frame
data=data[,c(5,3,1,2,4)]             # sort columns

# melt the data frame for plotting
data.m <- melt(data, id.vars='Names')

# plot everything
ggplot(data.m, aes(Names, value)) +   
  geom_bar(aes(fill = variable), position = "dodge", stat="identity")

Is this what you're after?

enter image description here

To clarify a little bit, in ggplot multiple grouping bar you had a data frame that looked like this:

> head(df)
  ID Type Annee X1PCE X2PCE X3PCE X4PCE X5PCE X6PCE
1  1    A  1980   450   338   154    36    13     9
2  2    A  2000   288   407   212    54    16    23
3  3    A  2020   196   434   246    68    19    36
4  4    B  1980   111   326   441    90    21    11
5  5    B  2000    63   298   443   133    42    21
6  6    B  2020    36   257   462   162    55    30

Since you have numerical values in columns 4-9, which would later be plotted on the y axis, this can be easily transformed with reshape and plotted.

For our current data set, we needed something similar, so we used freq=table(col(raw), as.matrix(raw)) to get this:

> data
   Names Very.Bad Bad Good Very.Good
1   Food        7   6    5         2
2  Music        5   5    7         3
3 People        6   3    7         4

Just imagine you have Very.Bad, Bad, Good and so on instead of X1PCE, X2PCE, X3PCE. See the similarity? But we needed to create such structure first. Hence the freq=table(col(raw), as.matrix(raw)).

Inner join of DataTables in C#

If you are allowed to use LINQ, take a look at the following example. It creates two DataTables with integer columns, fills them with some records, join them using LINQ query and outputs them to Console.

    DataTable dt1 = new DataTable();
    dt1.Columns.Add("CustID", typeof(int));
    dt1.Columns.Add("ColX", typeof(int));
    dt1.Columns.Add("ColY", typeof(int));

    DataTable dt2 = new DataTable();
    dt2.Columns.Add("CustID", typeof(int));
    dt2.Columns.Add("ColZ", typeof(int));

    for (int i = 1; i <= 5; i++)
    {
        DataRow row = dt1.NewRow();
        row["CustID"] = i;
        row["ColX"] = 10 + i;
        row["ColY"] = 20 + i;
        dt1.Rows.Add(row);

        row = dt2.NewRow();
        row["CustID"] = i;
        row["ColZ"] = 30 + i;
        dt2.Rows.Add(row);
    }

    var results = from table1 in dt1.AsEnumerable()
                 join table2 in dt2.AsEnumerable() on (int)table1["CustID"] equals (int)table2["CustID"]
                 select new
                 {
                     CustID = (int)table1["CustID"],
                     ColX = (int)table1["ColX"],
                     ColY = (int)table1["ColY"],
                     ColZ = (int)table2["ColZ"]
                 };
    foreach (var item in results)
    {
        Console.WriteLine(String.Format("ID = {0}, ColX = {1}, ColY = {2}, ColZ = {3}", item.CustID, item.ColX, item.ColY, item.ColZ));
    }
    Console.ReadLine();

// Output:
// ID = 1, ColX = 11, ColY = 21, ColZ = 31
// ID = 2, ColX = 12, ColY = 22, ColZ = 32
// ID = 3, ColX = 13, ColY = 23, ColZ = 33
// ID = 4, ColX = 14, ColY = 24, ColZ = 34
// ID = 5, ColX = 15, ColY = 25, ColZ = 35

Element count of an array in C++

No that would still produce the right value because you must define the array to be either all elements of a single type or pointers to a type. In either case the array size is known at compile time so sizeof(arr) / sizeof(arr[0]) always returns the element count.

Here is an example of how to use this correctly:

int nonDynamicArray[ 4 ];

#define nonDynamicArrayElementCount ( sizeof(nonDynamicArray) / sizeof(nonDynamicArray[ 0 ]) )

I'll go one further here to show when to use this properly. You won't use it very often. It is primarily useful when you want to define an array specifically so you can add elements to it without changing a lot of code later. It is a construct that is primarily useful for maintenance. The canonical example (when I think about it anyway ;-) is building a table of commands for some program that you intend to add more commands to later. In this example to maintain/improve your program all you need to do is add another command to the array and then add the command handler:

char        *commands[] = {  // <--- note intentional lack of explicit array size
    "open",
    "close",
    "abort",
    "crash"
};

#define kCommandsCount  ( sizeof(commands) / sizeof(commands[ 0 ]) )

void processCommand( char *command ) {
    int i;

    for ( i = 0; i < kCommandsCount; ++i ) {
        // if command == commands[ i ] do something (be sure to compare full string)
    }
}

Converting map to struct
  • the simplest way to do that is using encoding/json package

just for example:

package main
import (
    "fmt"
    "encoding/json"
)

type MyAddress struct {
    House string
    School string
}
type Student struct {
    Id int64
    Name string
    Scores float32
    Address MyAddress
    Labels []string
}

func Test() {

    dict := make(map[string]interface{})
    dict["id"] = 201902181425       // int
    dict["name"] = "jackytse"       // string
    dict["scores"] = 123.456        // float
    dict["address"] = map[string]string{"house":"my house", "school":"my school"}   // map
    dict["labels"] = []string{"aries", "warmhearted", "frank"}      // slice

    jsonbody, err := json.Marshal(dict)
    if err != nil {
        // do error check
        fmt.Println(err)
        return
    }

    student := Student{}
    if err := json.Unmarshal(jsonbody, &student); err != nil {
        // do error check
        fmt.Println(err)
        return
    }

    fmt.Printf("%#v\n", student)
}

func main() {
    Test()
}

Google Maps API v3 marker with label

I can't guarantee it's the simplest, but I like MarkerWithLabel. As shown in the basic example, CSS styles define the label's appearance and options in the JavaScript define the content and placement.

 .labels {
   color: red;
   background-color: white;
   font-family: "Lucida Grande", "Arial", sans-serif;
   font-size: 10px;
   font-weight: bold;
   text-align: center;
   width: 60px;     
   border: 2px solid black;
   white-space: nowrap;
 }

JavaScript: 

 var marker = new MarkerWithLabel({
   position: homeLatLng,
   draggable: true,
   map: map,
   labelContent: "$425K",
   labelAnchor: new google.maps.Point(22, 0),
   labelClass: "labels", // the CSS class for the label
   labelStyle: {opacity: 0.75}
 });

The only part that may be confusing is the labelAnchor. By default, the label's top left corner will line up to the marker pushpin's endpoint. Setting the labelAnchor's x-value to half the width defined in the CSS width property will center the label. You can make the label float above the marker pushpin with an anchor point like new google.maps.Point(22, 50).

In case access to the links above are blocked, I copied and pasted the packed source of MarkerWithLabel into this JSFiddle demo. I hope JSFiddle is allowed in China :|

Adjust UILabel height to text

I create this extension if you want

extension UILabel {
    func setSizeFont (sizeFont: CGFloat) {
        self.font =  UIFont(name: self.font.fontName, size: sizeFont)!
        self.sizeToFit()
    }
}

How to see PL/SQL Stored Function body in Oracle

 
SELECT text 
FROM all_source
where name = 'FGETALGOGROUPKEY'
order by line

alternatively:

select dbms_metadata.get_ddl('FUNCTION', 'FGETALGOGROUPKEY')
from dual;

Android Device Chooser -- device not showing up

I had the same problem and solved this way: my phone is a SonyEricsson Xperia X8 and wasn't recognized by windows 7 (but it was by Ubuntu). Hence I figured out it was a driver problem.

0) Pluged in my smartphone 1) Right clicked on Computer->Manage->Device Manager 2) There was a yellow exclamation mark on one item named something like "SEMC HUSB"... Double clicked on that item (that was actually related to the smarphone) and updated the drivers (previously downloaded from this page http://developer.sonymobile.com/downloads/drivers/sony-ericsson-x8-drivers/ and now everything works). I guess that you can find your proper dirvers via google if you have a different phone.

Cheers

TypeError: $(...).on is not a function

In my case this code solved my error :

(function (window, document, $) {
            'use strict';
             var $html = $('html');
             $('input[name="myiCheck"]').on('ifClicked', function (event) {
             alert("You clicked " + this.value);
             });
})(window, document, jQuery);

You don't should put your function inside $(document).ready

How to tell if a JavaScript function is defined

 
typeof callback === "function"

Using Javascript in CSS

I ran into a similar problem and have developed two standalone tools to accomplish this:

  • CjsSS.js is a Vanilla Javascript tool (so no external dependencies) that supports back to IE6.

  • ngCss is an Angular Module+Filter+Factory (aka: plugin) that supports Angular 1.2+ (so back to IE8)

Both of these tool sets allow you to do this in a STYLE tag or within an external *.css file:

    /*<script src='some.js'></script>
    <script>
        var mainColor = "#cccccc";
    </script>*/

    BODY {
        color: /*{{mainColor}}*/;
    }

And this in your on-page style attributes:

    <div style="color: {{mainColor}}" cjsss="#sourceCSS">blah</div>

or

    <div style="color: {{mainColor}}" ng-css="sourceCSS">blah</div>

NOTE: In ngCss, you could also do $scope.mainColor in place of var mainColor

By default, the Javascript is executed in a sandboxed IFRAME, but since you author your own CSS and host it on your own server (just like your *.js files) then XSS isn't an issue. But the sandbox provides that much more security and peace of mind.

CjsSS.js and ngCss fall somewhere in-between the other tools around to accomplish similar tasks:

  • LESS, SASS and Stylus are all Preprocessors only and require you to learn a new language and mangle your CSS. Basically they extended CSS with new language features. All are also limited to plugins developed for each platform while CjsSS.js and ngCss both allow you to include any Javascript library via <script src='blah.js'></script> straight in your CSS!

  • AbsurdJS saw the same problems and went the exact opposite direction of the Preprocessors above; rather than extending CSS, AbsurdJS created a Javascript library to generate CSS.

CjsSS.js and ngCss took the middle ground; you already know CSS, you already know Javascript, so just let them work together in a simple, intuitive way.

Is there a max array length limit in C++?

I would agree with the above, that if you're intializing your array with

 int myArray[SIZE]

then SIZE is limited by the size of an integer. But you can always malloc a chunk of memory and have a pointer to it, as big as you want so long as malloc doesnt return NULL.

Printing leading 0's in C

You place a zero before the minimum field width:

printf("%05d", zipcode);

TypeError: 'tuple' object does not support item assignment when swapping values

Evaluating "1,2,3" results in (1, 2, 3), a tuple. As you've discovered, tuples are immutable. Convert to a list before processing.

How to stop the Timer in android?

It says timer() is not available on android? You might find this article useful.

http://developer.android.com/resources/articles/timed-ui-updates.html

I was wrong. Timer() is available. It seems you either implement it the way it is one shot operation:

schedule(TimerTask task, Date when) // Schedule a task for single execution.

Or you cancel it after the first execution:

cancel()  // Cancels the Timer and all scheduled tasks.

http://developer.android.com/reference/java/util/Timer.html

Enable UTF-8 encoding for JavaScript

RobW is right on the first comment. You have to save the file in your IDE with encoding UTF-8. I moved my alert from .js file to my .html file and this solved the issue cause Visual Studio saves .html with UTF-8 encoding.

How to override !important?

I would like to add an answer to this that hasn't been mentioned, as I have tried all of the above to no avail. My specific situation is that I am using semantic-ui, which has built in !important attributes on elements (extremely annoying). I tried everything to override it, only in the end did one thing work (using jquery). It is as follows:

$('.active').css('cssText', 'border-radius: 0px !important');

How to add 10 days to current time in Rails

This definitely works and I use this wherever I need to add days to the current date:

Date.today + 5

Can I set an opacity only to the background image of a div?

This can be done by using the different div class for the text Hi There...

<div class="myDiv">
    <div class="bg">
   <p> Hi there</p>
</div>
</div>

Now you can apply the styles to the

tag. otherwise for bg class. I am sure it works fine

In PANDAS, how to get the index of a known value?

I think this may help you , both index and columns of the values.

value you are looking for is not duplicated:

poz=matrix[matrix==minv].dropna(axis=1,how='all').dropna(how='all')
value=poz.iloc[0,0]
index=poz.index.item()
column=poz.columns.item()

you can get its index and column

duplicated:

matrix=pd.DataFrame([[1,1],[1,np.NAN]],index=['q','g'],columns=['f','h'])
matrix
Out[83]: 
   f    h
q  1  1.0
g  1  NaN
poz=matrix[matrix==minv].dropna(axis=1,how='all').dropna(how='all')
index=poz.stack().index.tolist()
index
Out[87]: [('q', 'f'), ('q', 'h'), ('g', 'f')]

you will get a list

Nginx: stat() failed (13: permission denied)

I had the same issue, I am using Plesk Onyx 17 with Centos7. I could see this error in proxy_error_log under the affected domain's logs. All the dirs/files in /var/www/vhosts/ are owned by respective users (domain owners) and you can see that all of them are in psacln group. So solution was to add nginx also to this group, so he can see what he needs:

usermod -aG psacln nginx

And indeed, restart nginx and reload page with Ctrl+F5.

Exception of type 'System.OutOfMemoryException' was thrown.

I just restarted Visual Studio and did IISRESET which solved the problem.

Interpreting segfault messages

Error 4 means "The cause was a user-mode read resulting in no page being found.". There's a tool that decodes it here.

Here's the definition from the kernel. Keep in mind that 4 means that bit 2 is set and no other bits are set. If you convert it to binary that becomes clear.

/*
 * Page fault error code bits
 *      bit 0 == 0 means no page found, 1 means protection fault
 *      bit 1 == 0 means read, 1 means write
 *      bit 2 == 0 means kernel, 1 means user-mode
 *      bit 3 == 1 means use of reserved bit detected
 *      bit 4 == 1 means fault was an instruction fetch
 */
#define PF_PROT         (1<<0)
#define PF_WRITE        (1<<1)
#define PF_USER         (1<<2)
#define PF_RSVD         (1<<3)
#define PF_INSTR        (1<<4)

Now then, "ip 00007f9bebcca90d" means the instruction pointer was at 0x00007f9bebcca90d when the segfault happened.

"libQtWebKit.so.4.5.2[7f9beb83a000+f6f000]" tells you:

  • The object the crash was in: "libQtWebKit.so.4.5.2"
  • The base address of that object "7f9beb83a000"
  • How big that object is: "f6f000"

If you take the base address and subtract it from the ip, you get the offset into that object:

0x00007f9bebcca90d - 0x7f9beb83a000 = 0x49090D

Then you can run addr2line on it:

addr2line -e /usr/lib64/qt45/lib/libQtWebKit.so.4.5.2 -fCi 0x49090D
??
??:0

In my case it wasn't successful, either the copy I installed isn't identical to yours, or it's stripped.

How to link an image and target a new window

Assuming you want to show an Image thumbnail which is 50x50 pixels and link to the the actual image you can do 

<a href="path/to/image.jpg" alt="Image description" target="_blank" style="display: inline-block; width: 50px; height; 50px; background-image: url('path/to/image.jpg');"></a>

Of course it's best to give that link a class or id and put it in your css

how to pass value from one php page to another using session

Solution using just POST - no $_SESSION

page1.php

<form action="page2.php" method="post">
    <textarea name="textarea1" id="textarea1"></textarea><br />
    <input type="submit" value="submit" />
</form>

page2.php

<?php
    // this page outputs the contents of the textarea if posted
    $textarea1 = ""; // set var to avoid errors
    if(isset($_POST['textarea1'])){
        $textarea1 = $_POST['textarea1']
    }
?>
<textarea><?php echo $textarea1;?></textarea>

Solution using $_SESSION and POST

page1.php

<?php

    session_start(); // needs to be before anything else on page to use $_SESSION
    $textarea1 = "";
    if(isset($_POST['textarea1'])){
        $_SESSION['textarea1'] = $_POST['textarea1'];
    }

?>


<form action="page1.php" method="post">
    <textarea name="textarea1" id="textarea1"></textarea><br />
    <input type="submit" value="submit" />
</form>
<br /><br />
<a href="page2.php">Go to page2</a>

page2.php

<?php
    session_start(); // needs to be before anything else on page to use $_SESSION
    // this page outputs the textarea1 from the session IF it exists
    $textarea1 = ""; // set var to avoid errors
    if(isset($_SESSION['textarea1'])){
        $textarea1 = $_SESSION['textarea1']
    }
?>
<textarea><?php echo $textarea1;?></textarea>

WARNING!!! - This contains no validation!!!

Changing the child element's CSS when the parent is hovered

Not sure if there's terrible reasons to do this or not, but it seems to work with me on the latest version of Chrome/Firefox without any visible performance problems with quite a lot of elements on the page.

*:not(:hover)>.parent-hover-show{
    display:none;
}

But this way, all you need is to apply parent-hover-show to an element and the rest is taken care of, and you can keep whatever default display type you want without it always being "block" or making multiple classes for each type.

ALTER TABLE DROP COLUMN failed because one or more objects access this column

The @SqlZim's answer is correct but just to explain why this possibly have happened. I've had similar issue and this was caused by very innocent thing: adding default value to a column

ALTER TABLE MySchema.MyTable ADD 
  MyColumn int DEFAULT NULL;

But in the realm of MS SQL Server a default value on a colum is a CONSTRAINT. And like every constraint it has an identifier. And you cannot drop a column if it is used in a CONSTRAINT.

So what you can actually do avoid this kind of problems is always give your default constraints a explicit name, for example:

ALTER TABLE MySchema.MyTable ADD 
  MyColumn int NULL,
  CONSTRAINT DF_MyTable_MyColumn DEFAULT NULL FOR MyColumn;

You'll still have to drop the constraint before dropping the column, but you will at least know its name up front.

How to convert JSON data into a Python object

Modifying @DS response a bit, to load from a file:

def _json_object_hook(d): return namedtuple('X', d.keys())(*d.values())
def load_data(file_name):
  with open(file_name, 'r') as file_data:
    return file_data.read().replace('\n', '')
def json2obj(file_name): return json.loads(load_data(file_name), object_hook=_json_object_hook)

One thing: this cannot load items with numbers ahead. Like this:

{
  "1_first_item": {
    "A": "1",
    "B": "2"
  }
}

Because "1_first_item" is not a valid python field name.

HTTP Error 503, the service is unavailable

If the app pool immediately stops after you start it and your event log shows:

The worker process for application pool 'APP_POOL_NAME' encountered an error 'Cannot read configuration file ' trying to read configuration data from file '\?\', line number '0'. The data field contains the error code.

... you may experiencing a bug that was apparently introduced in the Windows 10 Fall Creators Update and/or .Net Framework v4.7.1. It can be resolved via the following workaround steps, which are from this answer to the related question Cannot read configuration file ' trying to read configuration data from file '\\?\<EMPTY>', line number '0'.

  1. Go to the drive your IIS is installed on, eg. C:\inetpub\temp\appPools\
  2. Delete the directory (or virtual directory) with the same name as your app pool.
  3. Recycle/Start your app pool again.

I have reported this bug to Microsoft by creating the following issue on the dotnet GitHub repo: After installing 4.7.1, IIS AppPool stops with "Cannot read configuration file".

EDIT

Microsoft responded that this is a known issue with the Windows setup process for the Fall Creators Update and was documented in KB 4050891, Web applications return HTTP Error 503 and WAS event 5189 on Windows 10 Version 1709 (Fall Creators Update). That article provides the following workaround procedure, which is similar to the one above. However, note that it will recycle all app pools regardless of whether they are affected by the issue.

  1. Open a Windows PowerShell window by using the Run as administrator option.
  2. Run the following commands:
    • Stop-Service -Force WAS
    • Remove-Item -Recurse -Force C:\inetpub\temp\appPools\*
    • Start-Service W3SVC

C# Help reading foreign characters using StreamReader

for Arabic, I used Encoding.GetEncoding(1256). it is working good.

How do you reset the stored credentials in 'git credential-osxkeychain'?

On Mac, use the command git credential-osxkeychain erase.

OR remove manually from keychain from Applications ? Utilities ? Keychain Access. Then remove the github.com keychain. Then use push; it will ask for the keychain access; then deny.

It will ask for the new username and password, add it then pushes a file for that.

After git push I found this error. Then I use the upper case- issue:

remote: Permission to user1/file.git denied to user2(previously exist user ). fatal: unable to access 'https://github.com/xxxxxxxxxxxx/': The requested URL returned error: 403

How to delete all data from solr and hbase

I've used this query to delete all my records.

http://host/solr/core-name/update?stream.body=%3Cdelete%3E%3Cquery%3E*:*%3C/query%3E%3C/delete%3E&commit=true

Getting the actual usedrange

This function returns the actual used range to the lower right limit. It returns "Nothing" if the sheet is empty.

'2020-01-26
Function fUsedRange() As Range
Dim lngLastRow As Long
Dim lngLastCol As Long
Dim rngLastCell As Range
    On Error Resume Next
    Set rngLastCell = ActiveSheet.Cells.Find("*", searchorder:=xlByRows, searchdirection:=xlPrevious)
    If rngLastCell Is Nothing Then  'look for data backwards in rows
        Set fUsedRange = Nothing
        Exit Function
    Else
        lngLastRow = rngLastCell.Row
    End If
    Set rngLastCell = ActiveSheet.Cells.Find("*", searchorder:=xlByColumns, searchdirection:=xlPrevious)
    If rngLastCell Is Nothing Then  'look for data backwards in columns
        Set fUsedRange = Nothing
        Exit Function
    Else
        lngLastCol = rngLastCell.Column
    End If
    Set fUsedRange = ActiveSheet.Range(Cells(1, 1), Cells(lngLastRow, lngLastCol))  'set up range
End Function

PHP CURL Enable Linux

If it's php 7 on ubuntu, try this

apt-get install php7.0-curl
/etc/init.d/apache2 restart

Check if an object exists

You can also use get_object_or_404(), it will raise a Http404 if the object wasn't found:

user_pass = log_in(request.POST) #form class
if user_pass.is_valid():
    cleaned_info = user_pass.cleaned_data
    user_object = get_object_or_404(User, email=cleaned_info['username'])
    # User object found, you are good to go!
    ...

How can a Java program get its own process ID?

Try Sigar . very extensive APIs. Apache 2 license.

private Sigar sigar;

public synchronized Sigar getSigar() {
    if (sigar == null) {
        sigar = new Sigar();
    }
    return sigar;
}

public synchronized void forceRelease() {
    if (sigar != null) {
        sigar.close();
        sigar = null;
    }
}

public long getPid() {
    return getSigar().getPid();
}

ListView with Add and Delete Buttons in each Row in android

You will first need to create a custom layout xml which will represent a single item in your list. You will add your two buttons to this layout along with any other items you want to display from your list.

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" > 

<TextView
    android:id="@+id/list_item_string"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerVertical="true"
    android:layout_alignParentLeft="true"
    android:paddingLeft="8dp"
    android:textSize="18sp"
    android:textStyle="bold" /> 

<Button
    android:id="@+id/delete_btn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"
    android:layout_centerVertical="true"
    android:layout_marginRight="5dp"
    android:text="Delete" /> 

<Button
    android:id="@+id/add_btn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_toLeftOf="@id/delete_btn"
    android:layout_centerVertical="true"
    android:layout_marginRight="10dp"
    android:text="Add" />

</RelativeLayout>

Next you will need to create a Custom ArrayAdapter Class which you will use to inflate your xml layout, as well as handle your buttons and on click events.

public class MyCustomAdapter extends BaseAdapter implements ListAdapter { 
private ArrayList<String> list = new ArrayList<String>(); 
private Context context; 



public MyCustomAdapter(ArrayList<String> list, Context context) { 
    this.list = list; 
    this.context = context; 
} 

@Override
public int getCount() { 
    return list.size(); 
} 

@Override
public Object getItem(int pos) { 
    return list.get(pos); 
} 

@Override
public long getItemId(int pos) { 
    return list.get(pos).getId();
    //just return 0 if your list items do not have an Id variable.
} 

@Override
public View getView(final int position, View convertView, ViewGroup parent) {
    View view = convertView;
    if (view == null) {
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
        view = inflater.inflate(R.layout.my_custom_list_layout, null);
    } 

    //Handle TextView and display string from your list
    TextView listItemText = (TextView)view.findViewById(R.id.list_item_string); 
    listItemText.setText(list.get(position)); 

    //Handle buttons and add onClickListeners
    Button deleteBtn = (Button)view.findViewById(R.id.delete_btn);
    Button addBtn = (Button)view.findViewById(R.id.add_btn);

    deleteBtn.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) { 
            //do something
            list.remove(position); //or some other task
            notifyDataSetChanged();
        }
    });
    addBtn.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) { 
            //do something
            notifyDataSetChanged();
        }
    });

    return view; 
} 
}

Finally, in your activity you can instantiate your custom ArrayAdapter class and set it to your listview.

public class MyActivity extends Activity { 

@Override
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_my_activity); 

    //generate list
    ArrayList<String> list = new ArrayList<String>();
    list.add("item1");
    list.add("item2");

    //instantiate custom adapter
    MyCustomAdapter adapter = new MyCustomAdapter(list, this);

    //handle listview and assign adapter
    ListView lView = (ListView)findViewById(R.id.my_listview);
    lView.setAdapter(adapter);
}

Hope this helps!

Trying to make bootstrap modal wider

Always have handy the un-minified CSS for bootstrap so you can see what styles they have on their components, then create a CSS file AFTER it, if you don't use LESS and over-write their mixins or whatever

This is the default modal css for 768px and up:

@media (min-width: 768px) {
  .modal-dialog {
    width: 600px;
    margin: 30px auto;
  }
  ...
}

They have a class modal-lg for larger widths

@media (min-width: 992px) {
  .modal-lg {
    width: 900px;
  }
}

If you need something twice the 600px size, and something fluid, do something like this in your CSS after the Bootstrap css and assign that class to the modal-dialog.

@media (min-width: 768px) {
  .modal-xl {
    width: 90%;
   max-width:1200px;
  }
}

HTML

<div class="modal-dialog modal-xl">

Demo: http://jsbin.com/yefas/1

Should a 502 HTTP status code be used if a proxy receives no response at all?

Yes. Empty or incomplete headers or response body typically caused by broken connections or server side crash can cause 502 errors if accessed via a gateway or proxy.

For more information about the network errors

https://en.wikipedia.org/wiki/List_of_HTTP_status_codes

How can I dynamically add items to a Java array?

Use an ArrayList or juggle to arrays to auto increment the array size.

What is the equivalent of the C++ Pair<L,R> in Java?

JavaFX (which comes bundled with Java 8) has the Pair< A,B > class

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

hope this one helps you out:

edittext1.setKeyListener(null);
edittext1.setCursorVisible(false);
edittext1.setPressed(false);
edittext1.setFocusable(false);

Formatting code in Notepad++

NPP+ v7.9.1 with the latest version of XMLTools can't format exported VBA code from Office 2016/2019 Word. It puts all the code on the same line since it strips the CRLF out. Moreover, when you enable "auto validation" it errors out on the first VBA line that is, Attribute VB_Name = "The VBA module name". So any of the xml tool validations apparently can't be used for VBA validation.

2D character array initialization in C

I think what you originally meant to do was to make an array only of characters, not of pointers:

char options[2][100];

options[0][0]='t';
options[0][1]='e';
options[0][2]='s';
options[0][3]='t';
options[0][4]='1';
options[0][5]='\0';  /* NUL termination of C string */

/* A standard C library function which copies strings. */
strcpy(options[1], "test2");

The code above shows two distinct methods of setting the character values in memory you have set aside to contain characters.

Should I use the Reply-To header when sending emails as a service to others?

You may want to consider placing the customer's name in the From header and your address in the Sender header:

From: Company A <[email protected]>
Sender: [email protected]

Most mailers will render this as "From [email protected] on behalf of Company A", which is accurate. And then a Reply-To of Company A's address won't seem out of sorts.

From RFC 5322:

The "From:" field specifies the author(s) of the message, that is, the mailbox(es) of the person(s) or system(s) responsible for the writing of the message. The "Sender:" field specifies the mailbox of the agent responsible for the actual transmission of the message. For example, if a secretary were to send a message for another person, the mailbox of the secretary would appear in the "Sender:" field and the mailbox of the actual author would appear in the "From:" field.

What is the difference between a Relational and Non-Relational Database?

First up let me start by saying why we need a database.

We need a database to help organise information in such a manner that we can retrieve that data stored in a efficient manner.

Examples of relational database management systems(SQL):

1)Oracle Database

2)SQLite

3)PostgreSQL

4)MySQL

5)Microsoft SQL Server

6)IBM DB2

Examples of non relational database management systems(NoSQL)

1)MongoDB

2)Cassandra

3)Redis

4)Couchbase

5)HBase

6)DocumentDB

7)Neo4j

Relational databases have normalized data, as in information is stored in tables in forms of rows and columns, and normally when data is in normalized form, it helps to reduce data redundancy, and the data in tables are normally related to each other, so when we want to retrieve the data, we can query the data by using join statements and retrieve data as per our need.This is suited when we want to have more writes, less reads, and not much data involved, also its really easy relatively to update data in tables than in non relational databases. Horizontal scaling not possible, vertical scaling possible to some extent.CAP(Consistency, Availability, Partition Tolerant), and ACID (Atomicity, Consistency, Isolation, Duration)compliance.

Let me show entering data to a relational database using PostgreSQL as an example.

First create a product table as follows:

CREATE TABLE products (
    product_no integer,
    name text,
    price numeric
);

then insert the data

INSERT INTO products (product_no, name, price) VALUES (1, 'Cheese', 9.99);

Let's look at another different example: enter image description here

Here in a relational database, we can link the student table and subject table using relationships, via foreign key, subject ID, but in a non relational database no need to have two documents, as no relationships, so we store all the subject details and student details in one document say student document, then data is getting duplicated, which makes updating records troublesome.

In non relational databases, there is no fixed schema, data is not normalized. no relationships between data is created, all data mostly put in one document. Well suited when handling lots of data, and can transfer lots of data at once, best where high amounts of reads and less writes, and less updates, bit difficult to query data, as no fixed schema. Horizontal and vertical scaling is possible.CAP (Consistency, Availability, Partition Tolerant)and BASE (Basically Available, soft state, Eventually consistent)compliance.

Let me show an example to enter data to a non relational database using Mongodb

db.users.insertOne({name: ‘Mary’, age: 28 , occupation: ‘writer’ })
db.users.insertOne({name: ‘Ben’ , age: 21})

Hence you can understand that to the database called db, and there is a collections called users, and document called insertOne to which we add data, and there is no fixed schema as our first record has 3 attributes, and second attribute has 2 attributes only, this is no problem in non relational databases, but this cannot be done in relational databases, as relational databases have a fixed schema.

Let's look at another different example

({Studname: ‘Ash’, Subname: ‘Mathematics’, LecturerName: ‘Mr. Oak’})

Hence we can see in non relational database we can enter both student details and subject details into one document, as no relationships defined in non relational databases, but here this way can lead to data duplication, and hence errors in updating can occur therefore.

Hope this explains everything

Django Reverse with arguments '()' and keyword arguments '{}' not found

The solution @miki725 is absolutely correct. Alternatively, if you would like to use the args attribute as opposed to kwargs, then you can simply modify your code as follows:

project_id = 4
reverse('edit_project', args=(project_id,))

An example of this can be found in the documentation. This essentially does the same thing, but the attributes are passed as arguments. Remember that any arguments that are passed need to be assigned a value before being reversed. Just use the correct namespace, which in this case is 'edit_project'.

Handling 'Sequence has no elements' Exception

Part of the answer to 'handle' the 'Sequence has no elements' Exception in VB is to test for empty

If Not (myMap Is Nothing) Then
' execute code
End if

Where MyMap is the sequence queried returning empty/null. FYI

Implement Validation for WPF TextBoxes

There a 3 ways to implement validation:

  1. Validation Rule
  2. Implementation of INotifyDataErrorInfo
  3. Implementation of IDataErrorInfo

Validation rule example:

public class NumericValidationRule : ValidationRule
{
    public Type ValidationType { get; set; }
    public override ValidationResult Validate(object value, CultureInfo cultureInfo)
    {
        string strValue = Convert.ToString(value);

        if (string.IsNullOrEmpty(strValue))
            return new ValidationResult(false, $"Value cannot be coverted to string.");
        bool canConvert = false;
        switch (ValidationType.Name)
        {

            case "Boolean":
                bool boolVal = false;
                canConvert = bool.TryParse(strValue, out boolVal);
                return canConvert ? new ValidationResult(true, null) : new ValidationResult(false, $"Input should be type of boolean");
            case "Int32":
                int intVal = 0;
                canConvert = int.TryParse(strValue, out intVal);
                return canConvert ? new ValidationResult(true, null) : new ValidationResult(false, $"Input should be type of Int32");
            case "Double":
                double doubleVal = 0;
                canConvert = double.TryParse(strValue, out doubleVal);
                return canConvert ? new ValidationResult(true, null) : new ValidationResult(false, $"Input should be type of Double");
            case "Int64":
                long longVal = 0;
                canConvert = long.TryParse(strValue, out longVal);
                return canConvert ? new ValidationResult(true, null) : new ValidationResult(false, $"Input should be type of Int64");
            default:
                throw new InvalidCastException($"{ValidationType.Name} is not supported");
        }
    }
}

XAML:

Very important: don't forget to set ValidatesOnTargetUpdated="True" it won't work without this definition.

 <TextBox x:Name="Int32Holder"
         IsReadOnly="{Binding IsChecked,ElementName=CheckBoxEditModeController,Converter={converters:BooleanInvertConverter}}"
         Style="{StaticResource ValidationAwareTextBoxStyle}"
         VerticalAlignment="Center">
    <!--Text="{Binding Converter={cnv:TypeConverter}, ConverterParameter='Int32', Path=ValueToEdit.Value, UpdateSourceTrigger=PropertyChanged, RelativeSource={RelativeSource AncestorType={x:Type UserControl}}}"-->
    <TextBox.Text>
        <Binding Path="Name"
                 Mode="TwoWay"
                 UpdateSourceTrigger="PropertyChanged"
                 Converter="{cnv:TypeConverter}"
                 ConverterParameter="Int32"
                 ValidatesOnNotifyDataErrors="True"
                 ValidatesOnDataErrors="True"
                 NotifyOnValidationError="True">
            <Binding.ValidationRules>
                <validationRules:NumericValidationRule ValidationType="{x:Type system:Int32}"
                                                       ValidatesOnTargetUpdated="True" />
            </Binding.ValidationRules>
        </Binding>
    </TextBox.Text>
    <!--NumericValidationRule-->
</TextBox>

INotifyDataErrorInfo example:

public abstract class ViewModelBase : INotifyPropertyChanged, INotifyDataErrorInfo
{

    #region INotifyPropertyChanged
    public event PropertyChangedEventHandler PropertyChanged;

    public void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
        ValidateAsync();
    }
    #endregion


    public virtual void OnLoaded()
    {
    }

    #region INotifyDataErrorInfo
    private ConcurrentDictionary<string, List<string>> _errors = new ConcurrentDictionary<string, List<string>>();

    public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged;

    public void OnErrorsChanged(string propertyName)
    {
        var handler = ErrorsChanged;
        if (handler != null)
            handler(this, new DataErrorsChangedEventArgs(propertyName));
    }

    public IEnumerable GetErrors(string propertyName)
    {
        List<string> errorsForName;
        _errors.TryGetValue(propertyName, out errorsForName);
        return errorsForName;
    }

    public bool HasErrors
    {
        get { return _errors.Any(kv => kv.Value != null && kv.Value.Count > 0); }
    }

    public Task ValidateAsync()
    {
        return Task.Run(() => Validate());
    }

    private object _lock = new object();
    public void Validate()
    {
        lock (_lock)
        {
            var validationContext = new ValidationContext(this, null, null);
            var validationResults = new List<ValidationResult>();
            Validator.TryValidateObject(this, validationContext, validationResults, true);

            foreach (var kv in _errors.ToList())
            {
                if (validationResults.All(r => r.MemberNames.All(m => m != kv.Key)))
                {
                    List<string> outLi;
                    _errors.TryRemove(kv.Key, out outLi);
                    OnErrorsChanged(kv.Key);
                }
            }

            var q = from r in validationResults
                    from m in r.MemberNames
                    group r by m into g
                    select g;

            foreach (var prop in q)
            {
                var messages = prop.Select(r => r.ErrorMessage).ToList();

                if (_errors.ContainsKey(prop.Key))
                {
                    List<string> outLi;
                    _errors.TryRemove(prop.Key, out outLi);
                }
                _errors.TryAdd(prop.Key, messages);
                OnErrorsChanged(prop.Key);
            }
        }
    }
    #endregion

}

View Model Implementation:

public class MainFeedViewModel : BaseViewModel//, IDataErrorInfo
{
    private ObservableCollection<FeedItemViewModel> _feedItems;
    [XmlIgnore]
    public ObservableCollection<FeedItemViewModel> FeedItems
    {
        get
        {
            return _feedItems;
        }
        set
        {
            _feedItems = value;
            OnPropertyChanged("FeedItems");
        }
    }
    [XmlIgnore]
    public ObservableCollection<FeedItemViewModel> FilteredFeedItems
    {
        get
        {
            if (SearchText == null) return _feedItems;

            return new ObservableCollection<FeedItemViewModel>(_feedItems.Where(x => x.Title.ToUpper().Contains(SearchText.ToUpper())));
        }
    }

    private string _title;
    [Required]
    [StringLength(20)]
    //[CustomNameValidationRegularExpression(5, 20)]
    [CustomNameValidationAttribute(3, 20)]
    public string Title
    {
        get { return _title; }
        set
        {
            _title = value;
            OnPropertyChanged("Title");
        }
    }
    private string _url;
    [Required]
    [StringLength(200)]
    [Url]
    //[CustomValidation(typeof(MainFeedViewModel), "UrlValidation")]
    /// <summary>
    /// Validation of URL should be with custom method like the one that implemented below, or with 
    /// </summary>
    public string Url
    {
        get { return _url; }
        set
        {
            _url = value;
            OnPropertyChanged("Url");
        }
    }

    public MainFeedViewModel(string url, string title)
    {
        Title = title;
        Url = url;
    }
    /// <summary>
    /// 
    /// </summary>
    public MainFeedViewModel()
    {

    }
    public MainFeedViewModel(ObservableCollection<FeedItemViewModel> feeds)
    {
        _feedItems = feeds;
    }


    private string _searchText;
    [XmlIgnore]
    public string SearchText
    {
        get { return _searchText; }
        set
        {
            _searchText = value;

            OnPropertyChanged("SearchText");
            OnPropertyChanged("FilteredFeedItems");
        }
    }

    #region Data validation local
    /// <summary>
    /// Custom URL validation method
    /// </summary>
    /// <param name="obj"></param>
    /// <param name="context"></param>
    /// <returns></returns>
    public static ValidationResult UrlValidation(object obj, ValidationContext context)
    {
        var vm = (MainFeedViewModel)context.ObjectInstance;
        if (!Uri.IsWellFormedUriString(vm.Url, UriKind.Absolute))
        {
            return new ValidationResult("URL should be in valid format", new List<string> { "Url" });
        }
        return ValidationResult.Success;
    }

    #endregion
}

XAML:

<UserControl x:Class="RssReaderTool.Views.AddNewFeedDialogView"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             mc:Ignorable="d"
             d:DesignHeight="300"
             d:DesignWidth="300">
    <FrameworkElement.Resources>
        <Style TargetType="{x:Type TextBox}">
            <Setter Property="Validation.ErrorTemplate">
                <Setter.Value>
                    <ControlTemplate x:Name="TextErrorTemplate">
                        <DockPanel LastChildFill="True">
                            <AdornedElementPlaceholder>
                                <Border BorderBrush="Red"
                                        BorderThickness="2" />
                            </AdornedElementPlaceholder>
                            <TextBlock FontSize="20"
                                       Foreground="Red">*?*</TextBlock>
                        </DockPanel>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
            <Style.Triggers>
                <Trigger Property="Validation.HasError"
                         Value="True">
                    <Setter Property="ToolTip"
                            Value="{Binding RelativeSource=
            {x:Static RelativeSource.Self},
            Path=(Validation.Errors)[0].ErrorContent}"></Setter>
                </Trigger>
            </Style.Triggers>
        </Style>
        <!--<Style TargetType="{x:Type TextBox}">
            <Style.Triggers>
                <Trigger Property="Validation.HasError"
                         Value="true">
                    <Setter Property="ToolTip"
                            Value="{Binding RelativeSource={x:Static RelativeSource.Self},
                        Path=(Validation.Errors)[0].ErrorContent}" />
                </Trigger>
            </Style.Triggers>
        </Style>-->
    </FrameworkElement.Resources>
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" />
            <ColumnDefinition Width="5" />
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="5" />
            <RowDefinition Height="Auto" />
            <RowDefinition Height="5" />
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>
        <TextBlock Text="Feed Name"
                   ToolTip="Display" />
        <TextBox Text="{Binding MainFeedViewModel.Title,UpdateSourceTrigger=PropertyChanged,ValidatesOnNotifyDataErrors=True,ValidatesOnDataErrors=True}"
                 Grid.Column="2" />

        <TextBlock Text="Feed Url"
                   Grid.Row="2" />
        <TextBox Text="{Binding MainFeedViewModel.Url,UpdateSourceTrigger=PropertyChanged,ValidatesOnNotifyDataErrors=True,ValidatesOnDataErrors=True}"
                 Grid.Column="2"
                 Grid.Row="2" />
    </Grid>
</UserControl>

IDataErrorInfo:

View Model:

public class OperationViewModel : ViewModelBase, IDataErrorInfo
{
    private const int ConstCodeMinValue = 1;
    private readonly IEventAggregator _eventAggregator;
    private OperationInfoDefinition _operation;
    private readonly IEntityFilterer _contextFilterer;
    private OperationDescriptionViewModel _description;

    public long Code
    {
        get { return _operation.Code; }
        set
        {
            if (SetProperty(value, _operation.Code, o => _operation.Code = o))
            {
                UpdateDescription();
            }
        }
    }

    public string Description
    {
        get { return _operation.Description; }
        set
        {
            if (SetProperty(value, _operation.Description, o => _operation.Description = o))
            {
                UpdateDescription();
            }
        }
    }

    public string FriendlyName
    {
        get { return _operation.FriendlyName; }
        set
        {
            if (SetProperty(value, _operation.FriendlyName, o => _operation.FriendlyName = o))
            {
                UpdateDescription();
            }
        }
    }

    public int Timeout
    {
        get { return _operation.Timeout; }
        set
        {
            if (SetProperty(value, _operation.Timeout, o => _operation.Timeout = o))
            {
                UpdateDescription();
            }
        }
    }

    public string Category
    {
        get { return _operation.Category; }
        set
        {
            if (SetProperty(value, _operation.Category, o => _operation.Category = o))
            {
                UpdateDescription();
            }
        }
    }

    public bool IsManual
    {
        get { return _operation.IsManual; }
        set
        {
            if (SetProperty(value, _operation.IsManual, o => _operation.IsManual = o))
            {
                UpdateDescription();
            }
        }
    }


    void UpdateDescription()
    {
        //some code
    }




    #region Validation




    #region IDataErrorInfo

    public ValidationResult Validate()
    {
        return ValidationService.Instance.ValidateNumber(Code, ConstCodeMinValue, long.MaxValue);
    }

    public string this[string columnName]
    {
        get
        {
            var validation = ValidationService.Instance.ValidateNumber(Code, ConstCodeMinValue, long.MaxValue);

            return validation.IsValid ? null : validation.ErrorContent.ToString();
        }
    }

    public string Error
    {
        get
        {
            var result = Validate();
            return result.IsValid ? null : result.ErrorContent.ToString();
        }
    }
    #endregion

    #endregion
}

XAML:

<controls:NewDefinitionControl x:Class="DiagnosticsDashboard.EntityData.Operations.Views.NewOperationView"
                               xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                               xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                               xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
                               xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
                               xmlns:views="clr-namespace:DiagnosticsDashboard.EntityData.Operations.Views"
                               xmlns:controls="clr-namespace:DiagnosticsDashboard.Core.Controls;assembly=DiagnosticsDashboard.Core"
                               xmlns:c="clr-namespace:DiagnosticsDashboard.Core.Validation;assembly=DiagnosticsDashboard.Core"
                               mc:Ignorable="d">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" />
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="40" />
            <RowDefinition Height="40" />
            <RowDefinition Height="40" />
            <RowDefinition Height="40" />
            <RowDefinition Height="40" />
            <RowDefinition Height="40" />
            <RowDefinition Height="*" />
            <RowDefinition Height="*" />
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>
        <Label Grid.Column="0"
               Grid.Row="0"
               Margin="5">Code:</Label>
        <Label Grid.Column="0"
               Grid.Row="1"
               Margin="5">Description:</Label>
        <Label Grid.Column="0"
               Grid.Row="2"
               Margin="5">Category:</Label>
        <Label Grid.Column="0"
               Grid.Row="3"
               Margin="5">Friendly Name:</Label>
        <Label Grid.Column="0"
               Grid.Row="4"
               Margin="5">Timeout:</Label>
        <Label Grid.Column="0"
               Grid.Row="5"
               Margin="5">Is Manual:</Label>
        <TextBox Grid.Column="1"
                 Text="{Binding Code,UpdateSourceTrigger=PropertyChanged,ValidatesOnDataErrors=True}"
                 Grid.Row="0"
                 Margin="5"/>
        <TextBox Grid.Column="1"
                 Grid.Row="1"
                 Margin="5"
                 Text="{Binding Description}" />
        <TextBox Grid.Column="1"
                 Grid.Row="2"
                 Margin="5"
                 Text="{Binding Category}" />
        <TextBox Grid.Column="1"
                 Grid.Row="3"
                 Margin="5"
                 Text="{Binding FriendlyName}" />
        <TextBox Grid.Column="1"
                 Grid.Row="4"
                 Margin="5"
                 Text="{Binding Timeout}" />
        <CheckBox Grid.Column="1"
                  Grid.Row="5"
                  Margin="5"
                  IsChecked="{Binding IsManual}"
                  VerticalAlignment="Center" />


    </Grid>
</controls:NewDefinitionControl>

Fastest way to add an Item to an Array

It depends on how often you insert or read. You can increase the array by more than one if needed.

numberOfItems = ??

' ...

If numberOfItems+1 >= arr.Length Then
    Array.Resize(arr, arr.Length + 10)
End If

arr(numberOfItems) = newItem
numberOfItems += 1

Also for A, you only need to get the array if needed.

Dim list As List(Of Integer)(arr) ' Do this only once, keep a reference to the list
                                  ' If you create a new List everything you add an item then this will never be fast

'...

list.Add(newItem)
arrayWasModified = True

' ...

Function GetArray()

    If arrayWasModified Then
        arr = list.ToArray()
    End If

    Return Arr
End Function

If you have the time, I suggest you convert it all to List and remove arrays.

* My code might not compile

VB.Net: Dynamically Select Image from My.Resources

This works for me at runtime too: 

UltraPictureBox1.Image = My.Resources.MyPicture

No strings involved and if I change the name it is automatically updated by refactoring.

Remove scroll bar track from ScrollView in Android

By using below, solved the problem

android:scrollbarThumbVertical="@null"

How to access parent scope from within a custom directive *with own scope* in AngularJS?

Here's a trick I used once: create a "dummy" directive to hold the parent scope and place it somewhere outside the desired directive. Something like:

module.directive('myDirectiveContainer', function () {
    return {
        controller: function ($scope) {
            this.scope = $scope;
        }
    };
});

module.directive('myDirective', function () {
    return {
        require: '^myDirectiveContainer',
        link: function (scope, element, attrs, containerController) {
            // use containerController.scope here...
        }
    };
});

and then

<div my-directive-container="">
    <div my-directive="">
    </div>
</div>

Maybe not the most graceful solution, but it got the job done.

How to use Comparator in Java to sort

Do not waste time implementing Sorting Algorithm by your own. Instead; use

Collections.sort() to sort data.

What does 'x packages are looking for funding' mean when running `npm install`?

When you run npm update in the command prompt, when it is done it will recommend you type a new command called npm fund.

When you run npm fund it will list all the modules and packages you have installed that were created by companies or organizations that need money for their IT projects. You will see a list of webpages where you can send them money. So "funds" means "Angular packages you installed that could use some money from you as an option to help support their businesses".

It's basically a list of the modules you have that need contributions or donations of money to their projects and which list websites where you can enter a credit card to help pay for them.

Post parameter is always null

If you are sure about your sent JSON then you must trace your API carefully:

  1. Install Microsoft.AspNet.WebApi.Tracing package
  2. Add config.EnableSystemDiagnosticsTracing(); in the WebApiConfig class inside Register method.

Now look at the Debug output and you will probably find an invalid ModelState log entry.

If ModelState is invalid you may find the real cause in its Errors:

No one can even guess such an exception:

Could not load file or assembly 'Newtonsoft.Json, Version=9.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

How do I remove all HTML tags from a string without knowing which tags are in it?

You can use the below code on your string and you will get the complete string without html part.

string title = "<b> Hulk Hogan's Celebrity Championship Wrestling &nbsp;&nbsp;&nbsp;<font color=\"#228b22\">[Proj # 206010]</font></b>&nbsp;&nbsp;&nbsp; (Reality Series, &nbsp;)".Replace("&nbsp;",string.Empty);            
        string s = Regex.Replace(title, "<.*?>", String.Empty);

How to Load Ajax in Wordpress

Personally i prefer to do ajax in wordpress the same way that i would do ajax on any other site. I create a processor php file that handles all my ajax requests and just use that URL. So this is, because of htaccess not exactly possible in wordpress so i do the following.

1.in my htaccess file that lives in my wp-content folder i add this below what's already there 

<FilesMatch "forms?\.php$">
Order Allow,Deny
Allow from all
</FilesMatch>

In this case my processor file is called forms.php - you would put this in your wp-content/themes/themeName folder along with all your other files such as header.php footer.php etc... it just lives in your theme root.

2.) In my ajax code i can then use my url like this 

$.ajax({
    url:'/wp-content/themes/themeName/forms.php',
    data:({
        someVar: someValue
    }),
    type: 'POST'
});

obviously you can add in any of your before, success or error type things you'd like ...but yea this is (i believe) the easier way to do it because you avoid all the silliness of telling wordpress in 8 different places what's going to happen and this also let's you avoid doing other things you see people doing where they put js code on the page level so they can dip into php where i prefer to keep my js files separate.

Bootstrap datetimepicker is not a function

I changed the import sequence without fixing the problem, until finally I installed moments and tempus dominius (Core and bootrap), using npm and include them in boostrap.js

try {
window.Popper = require('popper.js').default;
window.$ = window.jQuery = require('jquery');
require('moment'); /*added*/
require('bootstrap');
require('tempusdominus-bootstrap-4');/*added*/} catch (e) {}

jQuery: Change button text on click

its work short code

$('.SeeMore2').click(function(){ var $this = $(this).toggleClass('SeeMore2'); if($(this).hasClass('SeeMore2')) { $(this).text('See More');
} else { $(this).text('See Less'); } });

How to get main div container to align to centre?

I would omit the * { text-align:center } declaration, as it sets center alignment for all elements.

Usually with a fixed width container margin: 0 auto should be enough

Is object empty?

 
var x= {}
var y= {x:'hi'}
console.log(Object.keys(x).length===0)
console.log(Object.keys(y).length===0)

true
false

http://jsfiddle.net/j7ona6hz/1/

Request redirect to /Account/Login?ReturnUrl=%2f since MVC 3 install on server

Similar setup, identical problem. Some installations would work, but most would start redirecting (http 302) to /Account/Login?ReturnUrl=%2f after a successful login, even though we're not using Forms Authentication. In my case after trying everything else, the solution was to switch the Application Pool Managed Pipeline Mode from from Integrated to Classic, which cleared up the problem immediately.

What is the difference between syntax and semantics in programming languages?

He drinks rice (wrong semantic- meaningless, right syntax- grammar)

Hi drink water (right semantic- has meaning, wrong syntax- grammar)

How to find the foreach index?

These two loops are equivalent (bar the safety railings of course):

for ($i=0; $i<count($things); $i++) { ... }

foreach ($things as $i=>$thing) { ... }

eg

for ($i=0; $i<count($things); $i++) {
    echo "Thing ".$i." is ".$things[$i];
}

foreach ($things as $i=>$thing) {
    echo "Thing ".$i." is ".$thing;
}

“Origin null is not allowed by Access-Control-Allow-Origin” error for request made by application running from a file:// URL

You need to maybe add a HEADER in your called script, here is what I had to do in PHP:

header('Access-Control-Allow-Origin: *');

More details in Cross domain AJAX ou services WEB (in French).

Adding elements to a C# array

Since arrays implement IEnumerable<T> you can use Concat:

string[] strArr = { "foo", "bar" };
strArr = strArr.Concat(new string[] { "something", "new" });

Or what would be more appropriate would be to use a collection type that supports inline manipulation.

Storing Python dictionaries

For completeness, we should include ConfigParser and configparser which are part of the standard library in Python 2 and 3, respectively. This module reads and writes to a config/ini file and (at least in Python 3) behaves in a lot of ways like a dictionary. It has the added benefit that you can store multiple dictionaries into separate sections of your config/ini file and recall them. Sweet!

Python 2.7.x example.

import ConfigParser

config = ConfigParser.ConfigParser()

dict1 = {'key1':'keyinfo', 'key2':'keyinfo2'}
dict2 = {'k1':'hot', 'k2':'cross', 'k3':'buns'}
dict3 = {'x':1, 'y':2, 'z':3}

# Make each dictionary a separate section in the configuration
config.add_section('dict1')
for key in dict1.keys():
    config.set('dict1', key, dict1[key])
   
config.add_section('dict2')
for key in dict2.keys():
    config.set('dict2', key, dict2[key])

config.add_section('dict3')
for key in dict3.keys():
    config.set('dict3', key, dict3[key])

# Save the configuration to a file
f = open('config.ini', 'w')
config.write(f)
f.close()

# Read the configuration from a file
config2 = ConfigParser.ConfigParser()
config2.read('config.ini')

dictA = {}
for item in config2.items('dict1'):
    dictA[item[0]] = item[1]

dictB = {}
for item in config2.items('dict2'):
    dictB[item[0]] = item[1]

dictC = {}
for item in config2.items('dict3'):
    dictC[item[0]] = item[1]

print(dictA)
print(dictB)
print(dictC)

Python 3.X example.

import configparser

config = configparser.ConfigParser()

dict1 = {'key1':'keyinfo', 'key2':'keyinfo2'}
dict2 = {'k1':'hot', 'k2':'cross', 'k3':'buns'}
dict3 = {'x':1, 'y':2, 'z':3}

# Make each dictionary a separate section in the configuration
config['dict1'] = dict1
config['dict2'] = dict2
config['dict3'] = dict3

# Save the configuration to a file
f = open('config.ini', 'w')
config.write(f)
f.close()

# Read the configuration from a file
config2 = configparser.ConfigParser()
config2.read('config.ini')

# ConfigParser objects are a lot like dictionaries, but if you really
# want a dictionary you can ask it to convert a section to a dictionary
dictA = dict(config2['dict1'] )
dictB = dict(config2['dict2'] )
dictC = dict(config2['dict3'])

print(dictA)
print(dictB)
print(dictC)

Console output

{'key2': 'keyinfo2', 'key1': 'keyinfo'}
{'k1': 'hot', 'k2': 'cross', 'k3': 'buns'}
{'z': '3', 'y': '2', 'x': '1'}

Contents of config.ini

[dict1]
key2 = keyinfo2
key1 = keyinfo

[dict2]
k1 = hot
k2 = cross
k3 = buns

[dict3]
z = 3
y = 2
x = 1

Javascript Error Null is not an Object

Try loading your javascript after.

Try this:

<h2>Hello World!</h2>
<p id="myParagraph">This is an example website</p>

<form>
  <input type="text" id="myTextfield" placeholder="Type your name" />
  <input type="submit" id="myButton" value="Go" />
</form>

<script src="js/script.js" type="text/javascript"></script>

Placing an image to the top right corner - CSS

You can just do it like this:

#content {
    position: relative;
}
#content img {
    position: absolute;
    top: 0px;
    right: 0px;
}

<div id="content">
    <img src="images/ribbon.png" class="ribbon"/>
    <div>some text...</div>
</div>

"Instantiating" a List in Java?

Use List<Integer> list = new ArrayList<Integer>();

How is Docker different from a virtual machine?

1. Lightweight

This is probably the first impression for many docker learners.

First, docker images are usually smaller than VM images, makes it easy to build, copy, share.

Second, Docker containers can start in several milliseconds, while VM starts in seconds.

2. Layered File System

This is another key feature of Docker. Images have layers, and different images can share layers, make it even more space-saving and faster to build.

If all containers use Ubuntu as their base images, not every image has its own file system, but share the same underline ubuntu files, and only differs in their own application data.

3. Shared OS Kernel

Think of containers as processes!

All containers running on a host is indeed a bunch of processes with different file systems. They share the same OS kernel, only encapsulates system library and dependencies.

This is good for most cases(no extra OS kernel maintains) but can be a problem if strict isolations are necessary between containers.

Why it matters?

All these seem like improvements, not revolution. Well, quantitative accumulation leads to qualitative transformation.

Think about application deployment. If we want to deploy a new software(service) or upgrade one, it is better to change the config files and processes instead of creating a new VM. Because Creating a VM with updated service, testing it(share between Dev & QA), deploying to production takes hours, even days. If anything goes wrong, you got to start again, wasting even more time. So, use configuration management tool(puppet, saltstack, chef etc.) to install new software, download new files is preferred.

When it comes to docker, it's impossible to use a newly created docker container to replace the old one. Maintainance is much easier!Building a new image, share it with QA, testing it, deploying it only takes minutes(if everything is automated), hours in the worst case. This is called immutable infrastructure: do not maintain(upgrade) software, create a new one instead.

It transforms how services are delivered. We want applications, but have to maintain VMs(which is a pain and has little to do with our applications). Docker makes you focus on applications and smooths everything.

Running multiple commands in one line in shell

Using pipes seems weird to me. Anyway you should use the logical and Bash operator:

$ cp /templates/apple /templates/used && cp /templates/apple /templates/inuse && rm /templates/apples

If the cp commands fail, the rm will not be executed.

Or, you can make a more elaborated command line using a for loop and cmp.

How to show the text on a ImageButton?

Best way:

<Button 
android:text="OK" 
android:id="@+id/buttonok" 
android:background="@drawable/buttonok"
android:layout_width="match_parent" 
android:layout_height="wrap_content"/>

Why is AJAX returning HTTP status code 0?

I found another case where jquery gives you status code 0 -- if for some reason XMLHttpRequest is not defined, you'll get this error.

Obviously this won't normally happen on the web, but a bug in a nightly firefox build caused this to crop up in an add-on I was writing. :)

Trim spaces from end of a NSString

 
NSString* NSStringWithoutSpace(NSString* string)
{
    return [string stringByReplacingOccurrencesOfString:@" " withString:@""];
}

Rounded corners for <input type='text' /> using border-radius.htc for IE

if you are using for certain text field then use the class

<style>
  .inputForm{
      border-radius:5px;
      -moz-border-radius:5px;
      -webkit-border-radius:5px;
   }
</style>

and in html code use

 <input type="text" class="inputForm">

or if u want to do this for all the input type text field means use

<style>
    input[type="text"]{
      border-radius:5px;
      -moz-border-radius:5px;
      -webkit-border-radius:5px;
    }
 </style>

and in html code

<input type="text" name="name">

how do I insert a column at a specific column index in pandas?

Here is a very simple answer to this(only one line).

You can do that after you added the 'n' column into your df as follows. 

import pandas as pd
df = pd.DataFrame({'l':['a','b','c','d'], 'v':[1,2,1,2]})
df['n'] = 0

df
    l   v   n
0   a   1   0
1   b   2   0
2   c   1   0
3   d   2   0

# here you can add the below code and it should work.
df = df[list('nlv')]
df

    n   l   v
0   0   a   1
1   0   b   2
2   0   c   1
3   0   d   2



However, if you have words in your columns names instead of letters. It should include two brackets around your column names. 

import pandas as pd
df = pd.DataFrame({'Upper':['a','b','c','d'], 'Lower':[1,2,1,2]})
df['Net'] = 0
df['Mid'] = 2
df['Zsore'] = 2

df

    Upper   Lower   Net Mid Zsore
0   a       1       0   2   2
1   b       2       0   2   2
2   c       1       0   2   2
3   d       2       0   2   2

# here you can add below line and it should work 
df = df[list(('Mid','Upper', 'Lower', 'Net','Zsore'))]
df

   Mid  Upper   Lower   Net Zsore
0   2   a       1       0   2
1   2   b       2       0   2
2   2   c       1       0   2
3   2   d       2       0   2

Regex to remove letters, symbols except numbers

Try the following regex:

var removedText = self.val().replace(/[^0-9]/, '');

This will match every character that is not (^) in the interval 0-9.

Demo.

Postgres user does not exist?

psql: Logs me in with my default username

psql -U postgres: Logs me in as the postgres user

Sudo doesn't seem to be required for me.

I use Postgres.app for my OS X postgres database. It removed the headache of making sure the installation was working and the database server was launched properly. Check it out here: http://postgresapp.com

Edit: Credit to @Erwin Brandstetter for correcting my use of the arguments.

How do I use CSS with a ruby on rails application?

I did the following...

  1. place your css file in the app/assets/stylesheets folder.
  2. Add the stylesheet link <%= stylesheet_link_tag "filename" %> in your default layouts file (most likely application.html.erb)

I recommend this over using your public folder. You can also reference the stylesheet inline, such as in your index page.

Objective-C for Windows

If you are comfortable with Visual Studio environment,

Small project: jGRASP with gcc Large project: Cocotron

I heard there are emulators, but I could find only Apple II Emulator http://virtualapple.org/. It looks like limited to games.

Is it possible to convert char[] to char* in C?

Well, I'm not sure to understand your question...

In C, Char[] and Char* are the same thing.

Edit : thanks for this interesting link.

How to unsubscribe to a broadcast event in angularJS. How to remove function registered via $on

EDIT: The correct way to do this is in @LiviuT's answer!

You can always extend Angular's scope to allow you to remove such listeners like so:

//A little hack to add an $off() method to $scopes.
(function () {
  var injector = angular.injector(['ng']),
      rootScope = injector.get('$rootScope');
      rootScope.constructor.prototype.$off = function(eventName, fn) {
        if(this.$$listeners) {
          var eventArr = this.$$listeners[eventName];
          if(eventArr) {
            for(var i = 0; i < eventArr.length; i++) {
              if(eventArr[i] === fn) {
                eventArr.splice(i, 1);
              }
            }
          }
        }
      }
}());

And here's how it would work:

  function myEvent() {
    alert('test');
  }
  $scope.$on('test', myEvent);
  $scope.$broadcast('test');
  $scope.$off('test', myEvent);
  $scope.$broadcast('test');

And here's a plunker of it in action

org.hibernate.StaleStateException: Batch update returned unexpected row count from update [0]; actual row count: 0; expected: 1

In the Hibernate mapping file for the id property, if you use any generator class, for that property you should not set the value explicitly by using a setter method.

If you set the value of the Id property explicitly, it will lead the error above. Check this to avoid this error.

Super-simple example of C# observer/observable with delegates

In this model, you have publishers who will do some logic and publish an "event."
Publishers will then send out their event only to subscribers who have subscribed to receive the specific event.

In C#, any object can publish a set of events to which other applications can subscribe.
When the publishing class raises an event, all the subscribed applications are notified.
The following figure shows this mechanism.

enter image description here

Simplest Example possible on Events and Delegates in C#:

code is self explanatory, Also I've added the comments to clear out the code.

  using System;

public class Publisher //main publisher class which will invoke methods of all subscriber classes
{
    public delegate void TickHandler(Publisher m, EventArgs e); //declaring a delegate
    public TickHandler Tick;     //creating an object of delegate
    public EventArgs e = null;   //set 2nd paramter empty
    public void Start()     //starting point of thread
    {
        while (true)
        {
            System.Threading.Thread.Sleep(300);
            if (Tick != null)   //check if delegate object points to any listener classes method
            {
                Tick(this, e);  //if it points i.e. not null then invoke that method!
            }
        }
    }
}

public class Subscriber1                //1st subscriber class
{
    public void Subscribe(Publisher m)  //get the object of pubisher class
    {
        m.Tick += HeardIt;              //attach listener class method to publisher class delegate object
    }
    private void HeardIt(Publisher m, EventArgs e)   //subscriber class method
    {
        System.Console.WriteLine("Heard It by Listener");
    }

}
public class Subscriber2                   //2nd subscriber class
{
    public void Subscribe2(Publisher m)    //get the object of pubisher class
    {
        m.Tick += HeardIt;               //attach listener class method to publisher class delegate object
    }
    private void HeardIt(Publisher m, EventArgs e)   //subscriber class method
    {
        System.Console.WriteLine("Heard It by Listener2");
    }

}

class Test
{
    static void Main()
    {
        Publisher m = new Publisher();      //create an object of publisher class which will later be passed on subscriber classes
        Subscriber1 l = new Subscriber1();  //create object of 1st subscriber class
        Subscriber2 l2 = new Subscriber2(); //create object of 2nd subscriber class
        l.Subscribe(m);     //we pass object of publisher class to access delegate of publisher class
        l2.Subscribe2(m);   //we pass object of publisher class to access delegate of publisher class

        m.Start();          //starting point of publisher class
    }
}

Output:

Heard It by Listener

Heard It by Listener2

Heard It by Listener

Heard It by Listener2

Heard It by Listener . . . (infinite times)

How to concatenate text from multiple rows into a single text string in SQL server?

on top of Chris Shaffer answer

if your data may get repeated Such as

Tom
Ali
John
Ali
Tom
Mike

Instead of having Tom,Ali,John,Ali,Tom,Mike

You can use DISTINCT to avoid duplicates and get Tom,Ali,John,Mike

DECLARE @Names VARCHAR(8000) 
SELECT DISTINCT @Names = COALESCE(@Names + ',', '') + Name
FROM People
WHERE Name IS NOT NULL
SELECT @Names

Maven and adding JARs to system scope

mvn install:install-file -DgroupId=com.paic.maven -DartifactId=tplconfig-maven-plugin -Dversion=1.0 -Dpackaging=jar -Dfile=tplconfig-maven-plugin-1.0.jar -DgeneratePom=true

Install the jar to local repository.

How to convert JSON string to array

There is a problem with the string you are calling a json. I have made some changes to it below. If you properly format the string to a correct json, the code below works.

$str = '{
        "action" : "create",
        "record": {
            "type": "n$product",
            "fields": {
                "nname": "Bread",
                "nprice": 2.11
            },
            "namespaces": { "my.demo": "n" }
        }
    }';

    $response = json_decode($str, TRUE);
    echo '<br> action' . $response["action"] . '<br><br>';

How to close form

There are different methods to open or close winform. Form.Close() is one method in closing a winform.

When 'Form.Close()' execute , all resources created in that form are destroyed. Resources means control and all its child controls (labels , buttons) , forms etc.

Some other methods to close winform

  1. Form.Hide()
  2. Application.Exit()

Some methods to Open/Start a form

  1. Form.Show()
  2. Form.ShowDialog()
  3. Form.TopMost()

All of them act differently , Explore them !

Applications are expected to have a root view controller at the end of application launch

I upgraded to iOS9 and started getting this error out of nowhere. I was able to fix it but adding the below code to - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

NSArray *windows = [[UIApplication sharedApplication] windows];
for(UIWindow *window in windows) {
    if(window.rootViewController == nil){
        UIViewController* vc = [[UIViewController alloc]initWithNibName:nil bundle:nil];
        window.rootViewController = vc;
    }
}

How to get a random number between a float range?

Use random.uniform(a, b):

>>> random.uniform(1.5, 1.9)
1.8733202628557872

if (select count(column) from table) > 0 then

You cannot directly use a SQL statement in a PL/SQL expression:

SQL> begin
  2     if (select count(*) from dual) >= 1 then
  3        null;
  4     end if;
  5  end;
  6  /
        if (select count(*) from dual) >= 1 then
            *
ERROR at line 2:
ORA-06550: line 2, column 6:
PLS-00103: Encountered the symbol "SELECT" when expecting one of the following:
...
...

You must use a variable instead:

SQL> set serveroutput on
SQL>
SQL> declare
  2     v_count number;
  3  begin
  4     select count(*) into v_count from dual;
  5
  6     if v_count >= 1 then
  7             dbms_output.put_line('Pass');
  8     end if;
  9  end;
 10  /
Pass

PL/SQL procedure successfully completed.

Of course, you may be able to do the whole thing in SQL:

update my_table
set x = y
where (select count(*) from other_table) >= 1;

It's difficult to prove that something is not possible. Other than the simple test case above, you can look at the syntax diagram for the IF statement; you won't see a SELECT statement in any of the branches.

Detect if PHP session exists

 
function is_session_started()
{
    if ( php_sapi_name() !== 'cli' ) {
        if ( version_compare(phpversion(), '5.4.0', '>=') ) {
            return session_status() === PHP_SESSION_ACTIVE ? TRUE : FALSE;
        } else {
            return session_id() === '' ? FALSE : TRUE;
        }
    }
    return FALSE;
}

// Example
if ( is_session_started() === FALSE ) session_start();

Error: No Entity Framework provider found for the ADO.NET provider with invariant name 'System.Data.SqlClient'

Try adding the following runtime assembly bindings:

<runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="EntityFramework" publicKeyToken="b77a5c561934e089" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>

Python: Random numbers into a list

 
import random
my_randoms = [random.randrange(1, 101, 1) for _ in range(10)]

Move to next item using Java 8 foreach loop in stream

Using return; will work just fine. It will not prevent the full loop from completing. It will only stop executing the current iteration of the forEach loop.

Try the following little program:

public static void main(String[] args) {
    ArrayList<String> stringList = new ArrayList<>();
    stringList.add("a");
    stringList.add("b");
    stringList.add("c");

    stringList.stream().forEach(str -> {
        if (str.equals("b")) return; // only skips this iteration.

        System.out.println(str);
    });
}

Output:

a
c

Notice how the return; is executed for the b iteration, but c prints on the following iteration just fine.

Why does this work?

The reason the behavior seems unintuitive at first is because we are used to the return statement interrupting the execution of the whole method. So in this case, we expect the main method execution as a whole to be halted.

However, what needs to be understood is that a lambda expression, such as:

str -> {
    if (str.equals("b")) return;

    System.out.println(str);
}

... really needs to be considered as its own distinct "method", completely separate from the main method, despite it being conveniently located within it. So really, the return statement only halts the execution of the lambda expression.

The second thing that needs to be understood is that:

stringList.stream().forEach()

... is really just a normal loop under the covers that executes the lambda expression for every iteration.

With these 2 points in mind, the above code can be rewritten in the following equivalent way (for educational purposes only):

public static void main(String[] args) {
    ArrayList<String> stringList = new ArrayList<>();
    stringList.add("a");
    stringList.add("b");
    stringList.add("c");

    for(String s : stringList) {
        lambdaExpressionEquivalent(s);
    }
}

private static void lambdaExpressionEquivalent(String str) {
    if (str.equals("b")) {
        return;
    }

    System.out.println(str);
}

With this "less magic" code equivalent, the scope of the return statement becomes more apparent.

How to create a CPU spike with a bash command

I combined some of the answers and added a way to scale the stress to all available cpus: 

#!/bin/bash

function infinite_loop { 
    while [ 1 ] ; do
        # Force some computation even if it is useless to actually work the CPU
        echo $((13**99)) 1>/dev/null 2>&1
    done
}

# Either use environment variables for DURATION, or define them here
NUM_CPU=$(grep -c ^processor /proc/cpuinfo 2>/dev/null || sysctl -n hw.ncpu)
PIDS=()
for i in `seq ${NUM_CPU}` ;
do
# Put an infinite loop on each CPU
    infinite_loop &
    PIDS+=("$!")
done

# Wait DURATION seconds then stop the loops and quit
sleep ${DURATION}

# Parent kills its children 
for pid in "${PIDS[@]}"
do
    kill $pid
done

printf with std::string?

Printf is actually pretty good to use if size matters. Meaning if you are running a program where memory is an issue, then printf is actually a very good and under rater solution. Cout essentially shifts bits over to make room for the string, while printf just takes in some sort of parameters and prints it to the screen. If you were to compile a simple hello world program, printf would be able to compile it in less than 60, 000 bits as opposed to cout, it would take over 1 million bits to compile.

For your situation, id suggest using cout simply because it is much more convenient to use. Although, I would argue that printf is something good to know.

How to deploy a war file in JBoss AS 7?

Read the file $AS/standalone/deployments/README.txt

  • you have two different modes : auto-deploy mode and manual deploy mode
  • for the manual deploy mode you have to placed a marker files as described in the others posts

  • for the autodeploy mode : This is done via the "auto-deploy" attributes on the deployment-scanner element in the standalone.xml configuration file:

    <deployment-scanner scan-interval="5000" relative-to="jboss.server.base.dir"
path="deployments" auto-deploy-zipped="true" **auto-deploy-exploded="true"**/>

How to access model hasMany Relation with where condition?

I have fixed the similar issue by passing associative array as the first argument inside Builder::with method.

Imagine you want to include child relations by some dynamic parameters but don't want to filter parent results.

Model.php

public function child ()
{
    return $this->hasMany(ChildModel::class);
}

Then, in other place, when your logic is placed you can do something like filtering relation by HasMany class. For example (very similar to my case):

$search = 'Some search string';
$result = Model::query()->with(
    [
        'child' => function (HasMany $query) use ($search) {
            $query->where('name', 'like', "%{$search}%");
        }
    ]
);

Then you will filter all the child results but parent models will not filter. Thank you for attention.

sendmail: how to configure sendmail on ubuntu?

I got the top answer working (can't reply yet) after one small edit

This did not work for me:

FEATURE('authinfo','hash /etc/mail/auth/client-info')dnl

The first single quote for each string should be changed to a backtick (`) like this:

FEATURE(`authinfo',`hash /etc/mail/auth/client-info')dnl

After the change I run:

sudo sendmailconfig

And I'm in business :)

Get size of all tables in database

Here is a way to get all tables' sizes quickly with the following steps:

  1. Write the given T-SQL commands to list all database tables:

    select 'exec sp_spaceused ' + TABLE_NAME from INFORMATION_SCHEMA.TABLES where TABLE_TYPE = 'BASE TABLE'

  2. Now copy the list of database tables, and copy it into a new query analyzer window

    exec sp_spaceused table1
exec sp_spaceused table2
exec sp_spaceused table3
exec sp_spaceused table4
exec sp_spaceused table5

  3. In SQL query analyzer, select from top tool bar option Results to file (Ctrl + Shift + F).

  4. Now finally hit the Execute button red marked from the above tool bar.

  5. The Database size of all tables is now stored in a file on your computer.

    Enter image description here

How to insert tab character when expandtab option is on in Vim

You can disable expandtab option from within Vim as below:

:set expandtab!

or

:set noet

PS: And set it back when you are done with inserting tab, with "set expandtab" or "set et"

PS: If you have tab set equivalent to 4 spaces in .vimrc (softtabstop), you may also like to set it to 8 spaces in order to be able to insert a tab by pressing tab key once instead of twice (set softtabstop=8).

Switching to landscape mode in Android Emulator

This is now much more intuitive. The AVD interface now includes a sidebar with various functional shortcuts. The buttons circled in blue will rotate the device clockwise and counterclockwise on the screen.

enter image description here

iPhone Safari Web App opens links in new window

This is slightly adapted version of Sean's which was preventing back button

// this function makes anchor tags work properly on an iphone

$(document).ready(function(){
if (("standalone" in window.navigator) && window.navigator.standalone) {
  // For iOS Apps
  $("a").on("click", function(e){

    var new_location = $(this).attr("href");
    if (new_location != undefined && new_location.substr(0, 1) != "#" && new_location!='' && $(this).attr("data-method") == undefined){
      e.preventDefault();
      window.location = new_location;
    }
  });
}

});

Save multiple sheets to .pdf

Similar to Tim's answer - but with a check for 2007 (where the PDF export is not installed by default):

Public Sub subCreatePDF()

    If Not IsPDFLibraryInstalled Then
        'Better show this as a userform with a proper link:
        MsgBox "Please install the Addin to export to PDF. You can find it at http://www.microsoft.com/downloads/details.aspx?familyid=4d951911-3e7e-4ae6-b059-a2e79ed87041". 
        Exit Sub
    End If

    ActiveSheet.ExportAsFixedFormat Type:=xlTypePDF, _
        Filename:=ActiveWorkbook.Path & Application.PathSeparator & _
        ActiveSheet.Name & " für " & Range("SelectedName").Value & ".pdf", _
        Quality:=xlQualityStandard, IncludeDocProperties:=True, _
        IgnorePrintAreas:=False, OpenAfterPublish:=True
End Sub

Private Function IsPDFLibraryInstalled() As Boolean
'Credits go to Ron DeBruin (http://www.rondebruin.nl/pdf.htm)
    IsPDFLibraryInstalled = _
        (Dir(Environ("commonprogramfiles") & _
        "\Microsoft Shared\OFFICE" & _
        Format(Val(Application.Version), "00") & _
        "\EXP_PDF.DLL") <> "")
End Function

Javascript seconds to minutes and seconds

strftime.js (strftime github) is one of the best time formatting libraries. It's extremely light - 30KB - and effective. Using it you can convert seconds into time easily in one line of code, relying mostly on the native Date class.

When creating a new Date, each optional argument is positional as follows:

new Date(year, month, day, hours, minutes, seconds, milliseconds);

So if you initialize a new Date with all arguments as zero up to the seconds, you'll get:

var seconds = 150;
var date = new Date(0,0,0,0,0,seconds);
=> Sun Dec 31 1899 00:02:30 GMT-0500 (EST)

You can see that 150 seconds is 2-minutes and 30-seconds, as seen in the date created. Then using an strftime format ("%M:%S" for "MM:SS"), it will output your minutes' string.

var mm_ss_str = strftime("%M:%S", date);
=> "02:30"

In one line, it would look like:

var mm_ss_str = strftime('%M:%S', new Date(0,0,0,0,0,seconds));
=> "02:30"

Plus this would allow you to interchangeable support HH:MM:SS and MM:SS based on the number of seconds. For example:

# Less than an Hour (seconds < 3600)
var seconds = 2435;
strftime((seconds >= 3600 ? '%H:%M:%S' : '%M:%S'), new Date(0,0,0,0,0,seconds));
=> "40:35"

# More than an Hour (seconds >= 3600)
var seconds = 10050;
strftime((seconds >= 3600 ? '%H:%M:%S' : '%M:%S'), new Date(0,0,0,0,0,seconds));
=> "02:47:30"

And of course, you can simply pass whatever format you want to strftime if you want the time string to be more or less semantic.

var format = 'Honey, you said you\'d be read in %S seconds %M minutes ago!';
strftime(format, new Date(0,0,0,0,0,1210));
=> "Honey, you said you'd be read in 10 seconds 20 minutes ago!"

Hope this helps.

Difference between xcopy and robocopy

The most important difference is that robocopy will (usually) retry when an error occurs, while xcopy will not. In most cases, that makes robocopy far more suitable for use in a script.

Addendum: for completeness, there is one known edge case issue with robocopy; it may silently fail to copy files or directories whose names contain invalid UTF-16 sequences. If that's a problem for you, you may need to look at third-party tools, or write your own.

How do I put my website's logo to be the icon image in browser tabs?

It is called 'favicon' and you need to add below code to the header section of your website.

Simply add this to the <head> section.

<link rel="icon" href="/your_path_to_image/favicon.jpg">

Encrypt and decrypt a password in Java

Here is the algorithm I use to crypt with MD5.It returns your crypted output.

   public class CryptWithMD5 {
   private static MessageDigest md;

   public static String cryptWithMD5(String pass){
    try {
        md = MessageDigest.getInstance("MD5");
        byte[] passBytes = pass.getBytes();
        md.reset();
        byte[] digested = md.digest(passBytes);
        StringBuffer sb = new StringBuffer();
        for(int i=0;i<digested.length;i++){
            sb.append(Integer.toHexString(0xff & digested[i]));
        }
        return sb.toString();
    } catch (NoSuchAlgorithmException ex) {
        Logger.getLogger(CryptWithMD5.class.getName()).log(Level.SEVERE, null, ex);
    }
        return null;


   }
}

You cannot decrypt MD5, but you can compare outputs since if you put the same string in this method it will have the same crypted output.If you want to decrypt you need to use the SHA.You will never use decription for a users password.For that always use MD5.That exception is pretty redundant.It will never throw it.

Parsing xml using powershell

If you want to start with a file you can do this

[xml]$cn = Get-Content config.xml
$cn.xml.Section.BEName

Use PowerShell to Parse an XML File

Add property to an array of objects

I came up against this problem too, and in trying to solve it I kept crashing the chrome tab that was running my app. It looks like the spread operator for objects was the culprit.

With a little help from adrianolsk’s comment and sidonaldson's answer above, I used Object.assign() the output of the spread operator from babel, like so:

this.options.map(option => {
  // New properties to be added
  const newPropsObj = {
    newkey1:value1,
    newkey2:value2
  };

  // Assign new properties and return
  return Object.assign(option, newPropsObj);
});

How to change the ROOT application?

In Tomcat 7 with these changes, i'm able to access myAPP at / and ROOT at /ROOT

<Context path="" docBase="myAPP"/>
<Context path="ROOT" docBase="ROOT"/>

Add above to the <Host> section in server.xml

Difference between View and Request scope in managed beans

A @ViewScoped bean lives exactly as long as a JSF view. It usually starts with a fresh new GET request, or with a navigation action, and will then live as long as the enduser submits any POST form in the view to an action method which returns null or void (and thus navigates back to the same view). Once you refresh the page, or return a non-null string (even an empty string!) navigation outcome, then the view scope will end.

A @RequestScoped bean lives exactly as long a HTTP request. It will thus be garbaged by end of every request and recreated on every new request, hereby losing all changed properties.

A @ViewScoped bean is thus particularly more useful in rich Ajax-enabled views which needs to remember the (changed) view state across Ajax requests. A @RequestScoped one would be recreated on every Ajax request and thus fail to remember all changed view state. Note that a @ViewScoped bean does not share any data among different browser tabs/windows in the same session like as a @SessionScoped bean. Every view has its own unique @ViewScoped bean.

See also:

Error Importing SSL certificate : Not an X.509 Certificate

Many CAs will provide a cert in PKCS7 format.

According to Oracle documentation, the keytool commmand can handle PKCS#7 but sometimes it fails

The keytool command can import X.509 v1, v2, and v3 certificates, and PKCS#7 formatted certificate chains consisting of certificates of that type. The data to be imported must be provided either in binary encoding format or in printable encoding format (also known as Base64 encoding) as defined by the Internet RFC 1421 standard. In the latter case, the encoding must be bounded at the beginning by a string that starts with -----BEGIN, and bounded at the end by a string that starts with -----END.

If the PKCS7 file can't be imported try to transform it from PKCS7 to X.509:

openssl pkcs7 -print_certs -in certificate.p7b -out certificate.cer

store and retrieve a class object in shared preference

You could use GSON, using Gradle Build.gradle :

implementation 'com.google.code.gson:gson:2.8.0'

Then in your code, for example pairs of string/boolean with Kotlin :

        val nestedData = HashMap<String,Boolean>()
        for (i in 0..29) {
            nestedData.put(i.toString(), true)
        }
        val gson = Gson()
        val jsonFromMap = gson.toJson(nestedData)

Adding to SharedPrefs :

        val sharedPrefEditor = context.getSharedPreferences(_prefName, Context.MODE_PRIVATE).edit()
        sharedPrefEditor.putString("sig_types", jsonFromMap)
        sharedPrefEditor.apply()

Now to retrieve data :

val gson = Gson()
val sharedPref: SharedPreferences = context.getSharedPreferences(_prefName, Context.MODE_PRIVATE)
val json = sharedPref.getString("sig_types", "false")
val type = object : TypeToken<Map<String, Boolean>>() {}.type
val map = gson.fromJson(json, type) as LinkedTreeMap<String,Boolean>
for (key in map.keys) {
     Log.i("myvalues", key.toString() + map.get(key).toString())
}

Check if at least two out of three booleans are true

Not in context of performance but good code(extensible and readable code that can be reused)

     static boolean trueBooleans (int howMany,boolean ... bools)
     {
      int total = 0;

      for (boolean b:bools)
        if (b && (++total == howMany)) return true;


      return false;
    }

In my humble opinion when writing Java, easy handling unexpected changes and no duplicated code are more important than concise (domain of script languages) or fast program.

How to remove the last character from a bash grep output

you can strip the beginnings and ends of a string by N characters using this bash construct, as someone said already

$ fred=abcdefg.rpm
$ echo ${fred:1:-4}
bcdefg

HOWEVER, this is not supported in older versions of bash.. as I discovered just now writing a script for a Red hat EL6 install process. This is the sole reason for posting here. A hacky way to achieve this is to use sed with extended regex like this:

$ fred=abcdefg.rpm
$ echo $fred | sed -re 's/^.(.*)....$/\1/g'
bcdefg

How to generate random positive and negative numbers in Java

([my double-compatible primitive type here])(Math.random() * [my max value here] * (Math.random() > 0.5 ? 1 : -1))

example:

// need a random number between -500 and +500
long myRandomLong = (long)(Math.random() * 500 * (Math.random() > 0.5 ? 1 : -1));

MySQL - UPDATE query based on SELECT Query

Easy in MySQL:

UPDATE users AS U1, users AS U2 
SET U1.name_one = U2.name_colX
WHERE U2.user_id = U1.user_id

How to clone an InputStream?

Cloning an input stream might not be a good idea, because this requires deep knowledge about the details of the input stream being cloned. A workaround for this is to create a new input stream that reads from the same source again.

So using some Java 8 features this would look like this:

public class Foo {

    private Supplier<InputStream> inputStreamSupplier;

    public void bar() {
        procesDataThisWay(inputStreamSupplier.get());
        procesDataTheOtherWay(inputStreamSupplier.get());
    }

    private void procesDataThisWay(InputStream) {
        // ...
    }

    private void procesDataTheOtherWay(InputStream) {
        // ...
    }
}

This method has the positive effect that it will reuse code that is already in place - the creation of the input stream encapsulated in inputStreamSupplier. And there is no need to maintain a second code path for the cloning of the stream.

On the other hand, if reading from the stream is expensive (because a it's done over a low bandwith connection), then this method will double the costs. This could be circumvented by using a specific supplier that will store the stream content locally first and provide an InputStream for that now local resource.

Declare an array in TypeScript

 
let arr1: boolean[] = [];

console.log(arr1[1]);

arr1.push(true);

Google Apps Script to open a URL

This function opens a URL without requiring additional user interaction.

/**
 * Open a URL in a new tab.
 */
function openUrl( url ){
  var html = HtmlService.createHtmlOutput('<html><script>'
  +'window.close = function(){window.setTimeout(function(){google.script.host.close()},9)};'
  +'var a = document.createElement("a"); a.href="'+url+'"; a.target="_blank";'
  +'if(document.createEvent){'
  +'  var event=document.createEvent("MouseEvents");'
  +'  if(navigator.userAgent.toLowerCase().indexOf("firefox")>-1){window.document.body.append(a)}'                          
  +'  event.initEvent("click",true,true); a.dispatchEvent(event);'
  +'}else{ a.click() }'
  +'close();'
  +'</script>'
  // Offer URL as clickable link in case above code fails.
  +'<body style="word-break:break-word;font-family:sans-serif;">Failed to open automatically. <a href="'+url+'" target="_blank" onclick="window.close()">Click here to proceed</a>.</body>'
  +'<script>google.script.host.setHeight(40);google.script.host.setWidth(410)</script>'
  +'</html>')
  .setWidth( 90 ).setHeight( 1 );
  SpreadsheetApp.getUi().showModalDialog( html, "Opening ..." );
}

This method works by creating a temporary dialog box, so it will not work in contexts where the UI service is not accessible, such as the script editor or a custom G Sheets formula.

Check for false

Like this:

if(borrar())
{
   // Do something
}

If borrar() returns true then do something (if it is not false).

In jQuery how can I set "top,left" properties of an element with position values relative to the parent and not the document?

You could try jQuery UI's .position method.

$("#mydiv").position({
  of: $('#mydiv').parent(),
  my: 'left+200 top+200',
  at: 'left top'
});

Check the working demo.

How to affect other elements when one element is hovered

Big thanks to Mike and Robertc for their helpful posts!

If you have two elements in your HTML and you want to :hover over one and target a style change in the other the two elements must be directly related--parents, children or siblings. This means that the two elements either must be one inside the other or must both be contained within the same larger element.

I wanted to display definitions in a box on the right side of the browser as my users read through my site and :hover over highlighted terms; therefore, I did not want the 'definition' element to be displayed inside the 'text' element.

I almost gave up and just added javascript to my page, but this is the future dang it! We should not have to put up with back sass from CSS and HTML telling us where we have to place our elements to achieve the effects we want! In the end we compromised.

While the actual HTML elements in the file must be either nested or contained in a single element to be valid :hover targets to each other, the css position attribute can be used to display any element where ever you want. I used position:fixed to place the target of my :hover action where I wanted it on the user's screen regardless to its location in the HTML document.

The html:

<div id="explainBox" class="explainBox"> /*Common parent*/

  <a class="defP" id="light" href="http://en.wikipedia.or/wiki/Light">Light                            /*highlighted term in text*/
  </a> is as ubiquitous as it is mysterious. /*plain text*/

  <div id="definitions"> /*Container for :hover-displayed definitions*/
    <p class="def" id="light"> /*example definition entry*/ Light:
      <br/>Short Answer: The type of energy you see
    </p>
  </div>

</div>

The css:

/*read: "when user hovers over #light somewhere inside #explainBox
    set display to inline-block for #light directly inside of #definitions.*/

#explainBox #light:hover~#definitions>#light {
  display: inline-block;
}

.def {
  display: none;
}

#definitions {
  background-color: black;
  position: fixed;
  /*position attribute*/
  top: 5em;
  /*position attribute*/
  right: 2em;
  /*position attribute*/
  width: 20em;
  height: 30em;
  border: 1px solid orange;
  border-radius: 12px;
  padding: 10px;
}

In this example the target of a :hover command from an element within #explainBox must either be #explainBox or also within #explainBox. The position attributes assigned to #definitions force it to appear in the desired location (outside #explainBox) even though it is technically located in an unwanted position within the HTML document.

I understand it is considered bad form to use the same #id for more than one HTML element; however, in this case the instances of #light can be described independently due to their respective positions in uniquely #id'd elements. Is there any reason not to repeat the id #light in this case?

How to Delete Session Cookie?

A session cookie is just a normal cookie without an expiration date. Those are handled by the browser to be valid until the window is closed or program is quit.

But if the cookie is a httpOnly cookie (a cookie with the httpOnly parameter set), you cannot read, change or delete it from outside of HTTP (meaning it must be changed on the server).

How to normalize a vector in MATLAB efficiently? Any related built-in function?

Fastest by far (time is in comparison to Jacobs):

clc; clear all;
V = rand(1024*1024*32,1);
N = 10;
tic; 
for i=1:N, 
    d = 1/sqrt(V(1)*V(1)+V(2)*V(2)+V(3)*V(3)); 
    V1 = V*d;
end; 
toc % 1.5s

How can I use threading in Python?

I saw a lot of examples here where no real work was being performed, and they were mostly CPU-bound. Here is an example of a CPU-bound task that computes all prime numbers between 10 million and 10.05 million. I have used all four methods here:

import math
import timeit
import threading
import multiprocessing
from concurrent.futures import ThreadPoolExecutor, ProcessPoolExecutor


def time_stuff(fn):
    """
    Measure time of execution of a function
    """
    def wrapper(*args, **kwargs):
        t0 = timeit.default_timer()
        fn(*args, **kwargs)
        t1 = timeit.default_timer()
        print("{} seconds".format(t1 - t0))
    return wrapper

def find_primes_in(nmin, nmax):
    """
    Compute a list of prime numbers between the given minimum and maximum arguments
    """
    primes = []

    # Loop from minimum to maximum
    for current in range(nmin, nmax + 1):

        # Take the square root of the current number
        sqrt_n = int(math.sqrt(current))
        found = False

        # Check if the any number from 2 to the square root + 1 divides the current numnber under consideration
        for number in range(2, sqrt_n + 1):

            # If divisible we have found a factor, hence this is not a prime number, lets move to the next one
            if current % number == 0:
                found = True
                break

        # If not divisible, add this number to the list of primes that we have found so far
        if not found:
            primes.append(current)

    # I am merely printing the length of the array containing all the primes, but feel free to do what you want
    print(len(primes))

@time_stuff
def sequential_prime_finder(nmin, nmax):
    """
    Use the main process and main thread to compute everything in this case
    """
    find_primes_in(nmin, nmax)

@time_stuff
def threading_prime_finder(nmin, nmax):
    """
    If the minimum is 1000 and the maximum is 2000 and we have four workers,
    1000 - 1250 to worker 1
    1250 - 1500 to worker 2
    1500 - 1750 to worker 3
    1750 - 2000 to worker 4
    so let’s split the minimum and maximum values according to the number of workers
    """
    nrange = nmax - nmin
    threads = []
    for i in range(8):
        start = int(nmin + i * nrange/8)
        end = int(nmin + (i + 1) * nrange/8)

        # Start the thread with the minimum and maximum split up to compute
        # Parallel computation will not work here due to the GIL since this is a CPU-bound task
        t = threading.Thread(target = find_primes_in, args = (start, end))
        threads.append(t)
        t.start()

    # Don’t forget to wait for the threads to finish
    for t in threads:
        t.join()

@time_stuff
def processing_prime_finder(nmin, nmax):
    """
    Split the minimum, maximum interval similar to the threading method above, but use processes this time
    """
    nrange = nmax - nmin
    processes = []
    for i in range(8):
        start = int(nmin + i * nrange/8)
        end = int(nmin + (i + 1) * nrange/8)
        p = multiprocessing.Process(target = find_primes_in, args = (start, end))
        processes.append(p)
        p.start()

    for p in processes:
        p.join()

@time_stuff
def thread_executor_prime_finder(nmin, nmax):
    """
    Split the min max interval similar to the threading method, but use a thread pool executor this time.
    This method is slightly faster than using pure threading as the pools manage threads more efficiently.
    This method is still slow due to the GIL limitations since we are doing a CPU-bound task.
    """
    nrange = nmax - nmin
    with ThreadPoolExecutor(max_workers = 8) as e:
        for i in range(8):
            start = int(nmin + i * nrange/8)
            end = int(nmin + (i + 1) * nrange/8)
            e.submit(find_primes_in, start, end)

@time_stuff
def process_executor_prime_finder(nmin, nmax):
    """
    Split the min max interval similar to the threading method, but use the process pool executor.
    This is the fastest method recorded so far as it manages process efficiently + overcomes GIL limitations.
    RECOMMENDED METHOD FOR CPU-BOUND TASKS
    """
    nrange = nmax - nmin
    with ProcessPoolExecutor(max_workers = 8) as e:
        for i in range(8):
            start = int(nmin + i * nrange/8)
            end = int(nmin + (i + 1) * nrange/8)
            e.submit(find_primes_in, start, end)

def main():
    nmin = int(1e7)
    nmax = int(1.05e7)
    print("Sequential Prime Finder Starting")
    sequential_prime_finder(nmin, nmax)
    print("Threading Prime Finder Starting")
    threading_prime_finder(nmin, nmax)
    print("Processing Prime Finder Starting")
    processing_prime_finder(nmin, nmax)
    print("Thread Executor Prime Finder Starting")
    thread_executor_prime_finder(nmin, nmax)
    print("Process Executor Finder Starting")
    process_executor_prime_finder(nmin, nmax)

main()

Here are the results on my Mac OS X four-core machine

Sequential Prime Finder Starting
9.708213827005238 seconds
Threading Prime Finder Starting
9.81836523200036 seconds
Processing Prime Finder Starting
3.2467174359990167 seconds
Thread Executor Prime Finder Starting
10.228896902000997 seconds
Process Executor Finder Starting
2.656402041000547 seconds

What is the difference between `new Object()` and object literal notation?

There is no difference for a simple object without methods as in your example. However, there is a big difference when you start adding methods to your object.

Literal way:

function Obj( prop ) { 
    return { 
        p : prop, 
        sayHello : function(){ alert(this.p); }, 
    }; 
}

Prototype way:

function Obj( prop ) { 
    this.p = prop; 
} 
Obj.prototype.sayHello = function(){alert(this.p);};

Both ways allow creation of instances of Obj like this:

var foo = new Obj( "hello" );

However, with the literal way, you carry a copy of the sayHello method within each instance of your objects. Whereas, with the prototype way, the method is defined in the object prototype and shared between all object instances. If you have a lot of objects or a lot of methods, the literal way can lead to quite big memory waste.

Closing Bootstrap modal onclick

Close the modal box using javascript

$('#product-options').modal('hide');

Open the modal box using javascript

$('#product-options').modal('show');

Toggle the modal box using javascript

$('#myModal').modal('toggle');

Means close the modal if it's open and vice versa.

How to add an existing folder with files to SVN?

Let's say I have code in the directory ~/local_dir/myNewApp, and I want to put it under 'https://svn.host/existing_path/myNewApp' (while being able to ignore some binaries, vendor libraries, etc.).

  1. Create an empty folder in the repository svn mkdir https://svn.host/existing_path/myNewApp
  2. Go to the parent directory of the project, cd ~/local_dir
  3. Check out the empty directory over your local folder. Don't be afraid - the files you have locally will not be deleted. svn co https://svn.host/existing_path/myNewApp. If your folder has a different name locally than in the repository, you must specify it as an additional argument.
  4. You can see that svn st will now show all your files as ?, which means that they are not currently under revision control
  5. Perform svn add on files you want to add to the repository, and add others to svn:ignore. You may find some useful options with svn help add, for example --parents or --depth empty, when you want selectively add only some files/folders.
  6. Commit with svn ci

How to fix 'sudo: no tty present and no askpass program specified' error?

If you add this line to your /etc/sudoers (via visudo) it will fix this problem without having to disable entering your password and when an alias for sudo -S won't work (scripts calling sudo): 

Defaults visiblepw

Of course read the manual yourself to understand it, but I think for my use case of running in an LXD container via lxc exec instance -- /bin/bash its pretty safe since it isn't printing the password over a network.

Laravel Eloquent compare date from datetime field

If you're still wondering how to solve it.

I use

$protected $dates = ['created_at','updated_at','aired'];

In my model and in my where i do

where('aired','>=',time())

So just use the unix to compaire in where.

In views on the otherhand you have to use the date object.

Hope it helps someone!

How to get certain commit from GitHub project

If you want to go with any certain commit or want to code of any certain commit then you can use below command:

git checkout <BRANCH_NAME>
git reset --hard  <commit ID which code you want>
git push --force

Example:

 git reset --hard fbee9dd 
 git push --force

How to reload a page using JavaScript

Using a button or just put it inside an "a" (anchor) tag:

<input type="button" value="RELOAD" onclick="location.reload();" />

Try these for other needs:

Location Objects has three methods --

assign() Used to load a new document
reload() Used to reloads the current document.
replace() Used to replace the current document with a new one

Convert DateTime to String PHP

 
echo date_format($date,"Y/m/d H:i:s");

What is the best way to give a C# auto-property an initial value?

Have you tried using the DefaultValueAttribute or ShouldSerialize and Reset methods in conjunction with the constructor? I feel like one of these two methods is necessary if you're making a class that might show up on the designer surface or in a property grid.

What is the $? (dollar question mark) variable in shell scripting?

$? is used to find the return value of the last executed command. Try the following in the shell:

ls somefile
echo $?

If somefile exists (regardless whether it is a file or directory), you will get the return value thrown by the ls command, which should be 0 (default "success" return value). If it doesn't exist, you should get a number other then 0. The exact number depends on the program.

For many programs you can find the numbers and their meaning in the corresponding man page. These will usually be described as "exit status" and may have their own section.

Using margin / padding to space <span> from the rest of the <p>

Add this style to your span:

position:relative; 
top: 10px;

Demo: http://jsfiddle.net/BqTUS/3/

fetch in git doesn't get all branches

I had a similar problem, however in my case I could pull/push to the remote branch but git status didn't show the local branch state w.r.t the remote ones.

Also, in my case git config --get remote.origin.fetch didn't return anything

The problem is that there was a typo in the .git/config file in the fetch line of the respective remote block. Probably something I added by mistake previously (sometimes I directly look at this file, or even edit it)

So, check if your remote entry in the .git/config file is correct, e.g.:

[remote "origin"]
    url = https://[server]/[user or organization]/[repo].git
    fetch = +refs/heads/*:refs/remotes/origin/*

How eliminate the tab space in the column in SQL Server 2008

Try this code

SELECT REPLACE([Column], char(9), '') From [dbo.Table]

char(9) is the TAB character

Visual Studio Code - Convert spaces to tabs
  1. Highlight your Code (in file)
  2. Click Tab Size in bottom righthand corner of application window Tab Size in bottom righthand corner of application window image
  3. Select the appropriate Convert Indentation to Tabs Select the appropriate Convert Indentation to Tabs image

Android: show/hide status bar/power bar

 
 @Override
 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    //hide status bar
    requestWindowFeature( Window.FEATURE_NO_TITLE );
    getWindow().setFlags( WindowManager.LayoutParams.FLAG_FULLSCREEN,
            WindowManager.LayoutParams.FLAG_FULLSCREEN );


    setContentView(R.layout.activity_main);
}

Removing all line breaks and adding them after certain text

I have achieved this with following
Edit > Blank Operations > Remove Unnecessary Blank and EOL

Adding a Time to a DateTime in C#

Depending on how you format (and validate!) the date entered in the textbox, you can do this:

TimeSpan time;

if (TimeSpan.TryParse(textboxTime.Text, out time))
{
   // calendarDate is the DateTime value of the calendar control
   calendarDate = calendarDate.Add(time);
}
else
{
   // notify user about wrong date format
}

Note that TimeSpan.TryParse expects the string to be in the 'hh:mm' format (optional seconds).

UnicodeDecodeError: 'ascii' codec can't decode byte 0xc2

Python 2

The error is caused because ElementTree did not expect to find non-ASCII strings set the XML when trying to write it out. You should use Unicode strings for non-ASCII instead. Unicode strings can be made either by using the u prefix on strings, i.e. u'€' or by decoding a string with mystr.decode('utf-8') using the appropriate encoding.

The best practice is to decode all text data as it's read, rather than decoding mid-program. The io module provides an open() method which decodes text data to Unicode strings as it's read.

ElementTree will be much happier with Unicodes and will properly encode it correctly when using the ET.write() method.

Also, for best compatibility and readability, ensure that ET encodes to UTF-8 during write() and adds the relevant header.

Presuming your input file is UTF-8 encoded (0xC2 is common UTF-8 lead byte), putting everything together, and using the with statement, your code should look like:

with io.open('myText.txt', "r", encoding='utf-8') as f:
    data = f.read()

root = ET.Element("add")
doc = ET.SubElement(root, "doc")

field = ET.SubElement(doc, "field")
field.set("name", "text")
field.text = data

tree = ET.ElementTree(root)
tree.write("output.xml", encoding='utf-8', xml_declaration=True)

Output:

<?xml version='1.0' encoding='utf-8'?>
<add><doc><field name="text">data€</field></doc></add>