Programs & Examples On #Muenchian grouping

Muenchian Grouping is an XSLT technique for optimizing the grouping of data in an XSL Transform.

flutter corner radius with transparent background

As of May 1st 2019, use BottomSheetTheme.

MaterialApp(
    theme: ThemeData(
      // Draw all modals with a white background and top rounded corners
      bottomSheetTheme: BottomSheetThemeData(
        backgroundColor: Colors.white,
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.vertical(top: Radius.circular(10))
        )
      )
    ),

Introduced recently, using a theme to control the sheets style should be the most best to this problem.

If you want to theme different bottom sheets differently, include a new Theme object in the appropriate subtree to override the bottom sheet theme just for that area.

If for some reason you'd still like to override the theme manually when launching a bottom sheet, showBottomSheet and showModalBottomSheet now have a backgroundColor parameter. Use it like this:

 showModalBottomSheet(
    backgroundColor: Colors.transparent,
    context: context,
    builder: (c) {return NavSheet();},
  );

Using the theme allows bottom sheets to be re-used regardless of the app / app's current theme, and has none of the negative side effects of setting canvas color as mentioned.

How to change HTML Object element data attribute value in javascript

and in jquery:

$('element').attr('some attribute','some attributes value')

i.e

$('a').attr('href','http://www.stackoverflow.com/')

How to save an image locally using Python whose URL address I already know?

Version for Python 3

I adjusted the code of @madprops for Python 3

# getem.py
# python2 script to download all images in a given url
# use: python getem.py http://url.where.images.are

from bs4 import BeautifulSoup
import urllib.request
import shutil
import requests
from urllib.parse import urljoin
import sys
import time

def make_soup(url):
    req = urllib.request.Request(url, headers={'User-Agent' : "Magic Browser"}) 
    html = urllib.request.urlopen(req)
    return BeautifulSoup(html, 'html.parser')

def get_images(url):
    soup = make_soup(url)
    images = [img for img in soup.findAll('img')]
    print (str(len(images)) + " images found.")
    print('Downloading images to current working directory.')
    image_links = [each.get('src') for each in images]
    for each in image_links:
        try:
            filename = each.strip().split('/')[-1].strip()
            src = urljoin(url, each)
            print('Getting: ' + filename)
            response = requests.get(src, stream=True)
            # delay to avoid corrupted previews
            time.sleep(1)
            with open(filename, 'wb') as out_file:
                shutil.copyfileobj(response.raw, out_file)
        except:
            print('  An error occured. Continuing.')
    print('Done.')

if __name__ == '__main__':
    get_images('http://www.wookmark.com')

How can I convert a .jar to an .exe?

If your program is "publicly available non-commercial in nature" and has "a publicly available Web site that meets the basic quality standards", then you can try and get a free license of Excelsior. If its not then it's expensive, but still a viable option.

Program: https://www.excelsiorjet.com

As a side note: Here's a study of all existing Jar to EXE programs, which is a bit depressing - https://www.excelsior-usa.com/articles/java-to-exe.html

select into in mysql

Use the CREATE TABLE SELECT syntax.

http://dev.mysql.com/doc/refman/5.0/en/create-table-select.html

CREATE TABLE new_tbl SELECT * FROM orig_tbl;

Disable SSL fallback and use only TLS for outbound connections in .NET? (Poodle mitigation)

I found the simplest solution is to add two registry entries as follows (run this in a command prompt with admin privileges):

reg add HKLM\SOFTWARE\Microsoft\.NETFramework\v4.0.30319 /v SchUseStrongCrypto /t REG_DWORD /d 1 /reg:32

reg add HKLM\SOFTWARE\Microsoft\.NETFramework\v4.0.30319 /v SchUseStrongCrypto /t REG_DWORD /d 1 /reg:64

These entries seem to affect how the .NET CLR chooses a protocol when making a secure connection as a client.

There is more information about this registry entry here:

https://docs.microsoft.com/en-us/security-updates/SecurityAdvisories/2015/2960358#suggested-actions

Not only is this simpler, but assuming it works for your case, far more robust than a code-based solution, which requires developers to track protocol and development and update all their relevant code. Hopefully, similar environment changes can be made for TLS 1.3 and beyond, as long as .NET remains dumb enough to not automatically choose the highest available protocol.

NOTE: Even though, according to the article above, this is only supposed to disable RC4, and one would not think this would change whether the .NET client is allowed to use TLS1.2+ or not, for some reason it does have this effect.

NOTE: As noted by @Jordan Rieger in the comments, this is not a solution for POODLE, since it does not disable the older protocols a -- it merely allows the client to work with newer protocols e.g. when a patched server has disabled the older protocols. However, with a MITM attack, obviously a compromised server will offer the client an older protocol, which the client will then happily use.

TODO: Try to disable client-side use of TLS1.0 and TLS1.1 with these registry entries, however I don't know if the .NET http client libraries respect these settings or not:

https://docs.microsoft.com/en-us/windows-server/security/tls/tls-registry-settings#tls-10

https://docs.microsoft.com/en-us/windows-server/security/tls/tls-registry-settings#tls-11

How does the JPA @SequenceGenerator annotation work

Even though this question is very old and I stumbled upon it for my own issues with JPA 2.0 and Oracle sequences.

Want to share my research on some of the things -

Relationship between @SequenceGenerator(allocationSize) of GenerationType.SEQUENCE and INCREMENT BY in database sequence definition

Make sure @SequenceGenerator(allocationSize) is set to same value as INCREMENT BY in Database sequence definition to avoid problems (the same applies to the initial value).

For example, if we define the sequence in database with a INCREMENT BY value of 20, set the allocationsize in SequenceGenerator also to 20. In this case the JPA will not make a call to database until it reaches the next 20 mark while it increments each value by 1 internally. This saves database calls to get the next sequence number each time. The side effect of this is - Whenever the application is redeployed or the server is restarted in between, it'll call database to get the next batch and you'll see jumps in the sequence values. Also we need to make sure the database definition and the application setting to be in-sync which may not be possible all the time as both of them are managed by different groups and you can quickly lose control of. If database value is less than the allocationsize, you'll see PrimaryKey constraint errors due to duplicate values of Id. If the database value is higher than the allocationsize, you'll see jumps in the values of Id.

If the database sequence INCREMENT BY is set to 1 (which is what DBAs generally do), set the allocationSize as also 1 so that they are in-sync but the JPA calls database to get next sequence number each time.

If you don't want the call to database each time, use GenerationType.IDENTITY strategy and have the @Id value set by database trigger. With GenerationType.IDENTITY as soon as we call em.persist the object is saved to DB and a value to id is assigned to the returned object so we don't have to do a em.merge or em.flush. (This may be JPA provider specific..Not sure)

Another important thing -

JPA 2.0 automatically runs ALTER SEQUENCE command to sync the allocationSize and INCREMENT BY in database sequence. As mostly we use a different Schema name(Application user name) rather than the actual Schema where the sequence exists and the application user name will not have ALTER SEQUENCE privileges, you might see the below warning in the logs -

000004c1 Runtime W CWWJP9991W: openjpa.Runtime: Warn: Unable to cache sequence values for sequence "RECORD_ID_SEQ". Your application does not have permission to run an ALTER SEQUENCE command. Ensure that it has the appropriate permission to run an ALTER SEQUENCE command.

As the JPA could not alter the sequence, JPA calls database everytime to get next sequence number irrespective of the value of @SequenceGenerator.allocationSize. This might be a unwanted consequence which we need to be aware of.

To let JPA not to run this command, set this value - in persistence.xml. This ensures that JPA will not try to run ALTER SEQUENCE command. It writes a different warning though -

00000094 Runtime W CWWJP9991W: openjpa.Runtime: Warn: The property "openjpa.jdbc.DBDictionary=disableAlterSeqenceIncrementBy" is set to true. This means that the 'ALTER SEQUENCE...INCREMENT BY' SQL statement will not be executed for sequence "RECORD_ID_SEQ". OpenJPA executes this command to ensure that the sequence's INCREMENT BY value defined in the database matches the allocationSize which is defined in the entity's sequence. With this SQL statement disabled, it is the responsibility of the user to ensure that the entity's sequence definition matches the sequence defined in the database.

As noted in the warning, important here is we need to make sure @SequenceGenerator.allocationSize and INCREMENT BY in database sequence definition are in sync including the default value of @SequenceGenerator(allocationSize) which is 50. Otherwise it'll cause errors.

Removing underline with href attribute

Add a style with the attribute text-decoration:none;:

There are a number of different ways of doing this.

Inline style:

<a href="xxx.html" style="text-decoration:none;">goto this link</a>

Inline stylesheet:

<html>
<head>
<style type="text/css">
   a {
      text-decoration:none;
   }
</style>
</head>
<body>
<a href="xxx.html">goto this link</a>
</body>
</html>

External stylesheet:

<html>
<head>
<link rel="Stylesheet" href="stylesheet.css" />
</head>
<body>
<a href="xxx.html">goto this link</a>
</body>
</html>

stylesheet.css:

a {
      text-decoration:none;
   }

How to create a HTML Table from a PHP array?

Possibly your most versatile approach is to select a templating system.

e.printStackTrace equivalent in python

e.printStackTrace equivalent in python

In Java, this does the following (docs):

public void printStackTrace()

Prints this throwable and its backtrace to the standard error stream...

This is used like this:

try
{ 
// code that may raise an error
}
catch (IOException e)
{
// exception handling
e.printStackTrace();
}

In Java, the Standard Error stream is unbuffered so that output arrives immediately.

The same semantics in Python 2 are:

import traceback
import sys
try: # code that may raise an error
    pass 
except IOError as e: # exception handling
    # in Python 2, stderr is also unbuffered
    print >> sys.stderr, traceback.format_exc()
    # in Python 2, you can also from __future__ import print_function
    print(traceback.format_exc(), file=sys.stderr)
    # or as the top answer here demonstrates, use:
    traceback.print_exc()
    # which also uses stderr.

Python 3

In Python 3, we can get the traceback directly from the exception object (which likely behaves better for threaded code). Also, stderr is line-buffered, but the print function gets a flush argument, so this would be immediately printed to stderr:

    print(traceback.format_exception(None, # <- type(e) by docs, but ignored 
                                     e, e.__traceback__),
          file=sys.stderr, flush=True)

Conclusion:

In Python 3, therefore, traceback.print_exc(), although it uses sys.stderr by default, would buffer the output, and you may possibly lose it. So to get as equivalent semantics as possible, in Python 3, use print with flush=True.

Uses for the '&quot;' entity in HTML

As other answers pointed out, it is most likely generated by some tool.

But if I were the original author of the file, my answer would be: Consistency.

If I am not allowed to put double quotes in my attributes, why put them in the element's content ? Why do these specs always have these exceptional cases .. If I had to write the HTML spec, I would say All double quotes need to be encoded. Done.

Today it is like In attribute values we need to encode double quotes, except when the attribute value itself is defined by single quotes. In the content of elements, double quotes can be, but are not required to be, encoded. (And I am surely forgetting some cases here).

Double quotes are a keyword of the spec, encode them. Lesser/greater than are a keyword of the spec, encode them. etc..

How to code a BAT file to always run as admin mode?

You use runas to launch a program as a specific user:

runas /user:Administrator Example1Server.exe

How do you clear the SQL Server transaction log?

This technique that John recommends is not recommended as there is no guarantee that the database will attach without the log file. Change the database from full to simple, force a checkpoint and wait a few minutes. The SQL Server will clear the log, which you can then shrink using DBCC SHRINKFILE.

How can I debug a Perl script?

To run your script under the Perl debugger you should use the -d switch:

perl -d script.pl

But Perl is flexible. It supplies some hooks, and you may force the debugger to work as you want

So to use different debuggers you may do:

perl -d:DebugHooks::Terminal script.pl
# OR
perl -d:Trepan script.pl

Look these modules here and here.

There are several most interesting Perl modules that hook into Perl debugger internals: Devel::NYTProf and Devel::Cover

And many others.

Wait until flag=true

I tried to used @Kiran approach like follow:

checkFlag: function() {
  var currentObject = this; 
  if(flag == false) {
      setTimeout(currentObject.checkFlag, 100); 
   } else {
     /* do something*/
   }
}

(framework that I am using force me to define functions this way). But without success because when execution come inside checkFlag function second time, this is not my object it is Window. So, I finished with code below

checkFlag: function() {
    var worker = setInterval (function(){
         if(flag == true){             
             /* do something*/
              clearInterval (worker);
         } 
    },100);
 }

php random x digit number

Here is a simple solution without any loops or any hassle which will allow you to create random string with characters, numbers or even with special symbols.

$randomNum = substr(str_shuffle("0123456789"), 0, $x);

where $x can be number of digits

Eg. substr(str_shuffle("0123456789"), 0, 5);

Results after a couple of executions

98450
79324
23017
04317
26479

You can use the same code to generate random string also, like this

$randomNum=substr(str_shuffle("0123456789abcdefghijklmnopqrstvwxyzABCDEFGHIJKLMNOPQRSTVWXYZ"), 0, $x);

Results with $x = 11

FgHmqpTR3Ox
O9BsNgcPJDb
1v8Aw5b6H7f
haH40dmAxZf
0EpvHL5lTKr

Is there a "null coalescing" operator in JavaScript?

Note that React's create-react-app tool-chain supports the null-coalescing since version 3.3.0 (released 5.12.2019). From the release notes:

Optional Chaining and Nullish Coalescing Operators

We now support the optional chaining and nullish coalescing operators!

// Optional chaining
a?.(); // undefined if `a` is null/undefined
b?.c; // undefined if `b` is null/undefined

// Nullish coalescing
undefined ?? 'some other default'; // result: 'some other default'
null ?? 'some other default'; // result: 'some other default'
'' ?? 'some other default'; // result: ''
0 ?? 300; // result: 0
false ?? true; // result: false

This said, in case you use create-react-app 3.3.0+ you can start using the null-coalesce operator already today in your React apps.

How do I find the version of Apache running without access to the command line?

If they have error pages enabled, you can go to a non-existent page and look at the bottom of the 404 page.

WPF Datagrid Get Selected Cell Value

Ok after doing reverse engineering and a little pixie dust of reflection, one can do this operation on SelectedCells (at any point) to get all (regardless of selected on one row or many rows) the data from one to many selected cells:

MessageBox.Show(

string.Join(", ", myGrid.SelectedCells
                        .Select(cl => cl.Item.GetType()
                                             .GetProperty(cl.Column.SortMemberPath)
                                             .GetValue(cl.Item, null)))

               );

I tried this on text (string) fields only though a DateTime field should return a value the initiate ToString(). Also note that SortMemberPath is not the same as Header so that should always provide the proper property to reflect off of.

<DataGrid ItemsSource="{Binding MyData}"                      
          AutoGenerateColumns="True"
          Name="myGrid"
          IsReadOnly="True"
          SelectionUnit="Cell"
          SelectionMode="Extended">

select records from postgres where timestamp is in certain range

Search till the seconds for the timestamp column in postgress

select * from "TableName" e
    where timestamp >= '2020-08-08T13:00:00' and timestamp < '2020-08-08T17:00:00';

Query grants for a table in postgres

Here is a script which generates grant queries for a particular table. It omits owner's privileges.

SELECT 
    format (
      'GRANT %s ON TABLE %I.%I TO %I%s;',
      string_agg(tg.privilege_type, ', '),
      tg.table_schema,
      tg.table_name,
      tg.grantee,
      CASE
        WHEN tg.is_grantable = 'YES' 
        THEN ' WITH GRANT OPTION' 
        ELSE '' 
      END
    )
  FROM information_schema.role_table_grants tg
  JOIN pg_tables t ON t.schemaname = tg.table_schema AND t.tablename = tg.table_name
  WHERE
    tg.table_schema = 'myschema' AND
    tg.table_name='mytable' AND
    t.tableowner <> tg.grantee
  GROUP BY tg.table_schema, tg.table_name, tg.grantee, tg.is_grantable;

Exiting from python Command Line

"exit" is a valid variable name that can be used in your Python program. You wouldn't want to exit the interpreter when you're just trying to see the value of that variable.

How should strace be used?

Strace is a tool that tells you how your application interacts with your operating system.

It does this by telling you what OS system calls your application uses and with what parameters it calls them.

So for instance you see what files your program tries to open, and weather the call succeeds.

You can debug all sorts of problems with this tool. For instance if application says that it cannot find library that you know you have installed you strace would tell you where the application is looking for that file.

And that is just a tip of the iceberg.

JOptionPane Yes or No window

You are writing if(true) so it will always show "Hello " message.

You should take decision on the basis of value of n returned.

Return Max Value of range that is determined by an Index & Match lookup

You don't need an index match formula. You can use this array formula. You have to press CTL + SHIFT + ENTER after you enter the formula.

=MAX(IF((A1:A6=A10)*(B1:B6=B10),C1:F6))

SNAPSHOT

enter image description here

Making PHP var_dump() values display one line per value

I didn't wanna stop using var_dump($variable);die(); and using pre tags and loops seems overkill to me, so since I am looking at the dump in a browser, I just right click the page and choose Inspect (I use Chrome). The Elements section of the Developer Tools show the variable in a very readable format.

OpenCV - Saving images to a particular folder of choice

Thank you everyone. Your ways are perfect. I would like to share another way I used to fix the problem. I used the function os.chdir(path) to change local directory to path. After which I saved image normally.

Read data from a text file using Java

Try this just a little search in Google

import java.io.*;
class FileRead 
{
   public static void main(String args[])
  {
      try{
    // Open the file that is the first 
    // command line parameter
    FileInputStream fstream = new FileInputStream("textfile.txt");
    // Get the object of DataInputStream
    DataInputStream in = new DataInputStream(fstream);
        BufferedReader br = new BufferedReader(new InputStreamReader(in));
    String strLine;
    //Read File Line By Line
    while ((strLine = br.readLine()) != null)   {
      // Print the content on the console
      System.out.println (strLine);
    }
    //Close the input stream
    in.close();
    }catch (Exception e){//Catch exception if any
      System.err.println("Error: " + e.getMessage());
    }
  }
}

Excel formula is only showing the formula rather than the value within the cell in Office 2010

Check the formatting (right click on cell, Format Cells). Under tab "Number" the category should be "General". If, for instance, it's "Text" anything typed in would be treated as a string rather than a formula to be interpreted.

flutter run: No connected devices

If the emulator is running and is not being detected by the flutter and adb devices then try connecting it manually by using the following command

abd connect 127.0.0.1:62001

If it fails to connect, try again. The following message should appear

connected to 127.0.0.1:62001

Then try flutter doctor or adb devices to make sure it has been connected successfully.

How do I uninstall a Windows service if the files do not exist anymore?

If the original Service .InstallLog and .InstallState files are still in the folder, you can try reinstalling the executable to replace the files, then use InstallUtil /u, then uninstall the program. It's a bit convoluted, but worked in a particular instance for me.

How do I increase the contrast of an image in Python OpenCV

img = cv2.imread("/x2.jpeg")

image = cv2.resize(img, (1800, 1800))

alpha=1.5
beta=20

new_image=cv2.addWeighted(image,alpha,np.zeros(image.shape, image.dtype),0,beta)

cv2.imshow("new",new_image)
cv2.waitKey(0)
cv2.destroyAllWindows()

Does Java support default parameter values?

It is not supported in java as in other language for ex. Kotlin.

Change/Get check state of CheckBox

var val = $("#checkboxId").is(":checked");

How to correctly write async method?

You are calling DoDownloadAsync() but you don't wait it. So your program going to the next line. But there is another problem, Async methods should return Task or Task<T>, if you return nothing and you want your method will be run asyncronously you should define your method like this:

private static async Task DoDownloadAsync()     {         WebClient w = new WebClient();          string txt = await w.DownloadStringTaskAsync("http://www.google.com/");         Debug.WriteLine(txt);     } 

And in Main method you can't await for DoDownloadAsync, because you can't use await keyword in non-async function, and you can't make Main async. So consider this:

var result = DoDownloadAsync();  Debug.WriteLine("DoDownload done"); result.Wait(); 

How can I set up an editor to work with Git on Windows?

Those of you using Git on Windows: What tool do you use to edit your commit messages, and what did you have to do to make it work?

The tool that I find the most useful as both my git editor and my general-purpose code editor, in both Windows and Linux, is Sublime Text 3. It works really well, but requires a little bit of setup to get it just right, so I've fully documented that fully here:

Side note about my main editor: for big projects I use Eclipse as my primary editor, and Sublime Text 3 as my git editor and additional file editor when I need to make use of its advanced features such as multi-cursor mode, vertical/column selection mode, etc. For small to medium projects I use just Sublime Text 3 by itself. For setup instructions for Eclipse, see my PDF document here.

How to acces external json file objects in vue.js app

If your file looks like this:

[
    {
        "firstname": "toto",
        "lastname": "titi"
    },
    {
        "firstname": "toto2",
        "lastname": "titi2"
    },
]

You can do:

import json from './json/data.json';
// ....
json.forEach(x => { console.log(x.firstname, x.lastname); });

Debug/run standard java in Visual Studio Code IDE and OS X?

I can tell you for Windows.

  1. Install Java Extension Pack and Code Runner Extension from VS Code Extensions.

  2. Edit your java home location in VS Code settings, "java.home": "C:\\Program Files\\Java\\jdk-9.0.4".

  3. Check if javac is recognized in VS Code internal terminal. If this check fails, try opening VS Code as administrator.

  4. Create a simple Java program in Main.java file as:

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello world");     
    }
}

Note: Do not add package in your main class.

  1. Right click anywhere on the java file and select run code.

  2. Check the output in the console.

Done, hope this helps.

How to show Error & Warning Message Box in .NET/ How to Customize MessageBox

You should add namespace if you are not using it:

System.Windows.Forms.MessageBox.Show("Some text", "Some title", 
    System.Windows.Forms.MessageBoxButtons.OK, 
    System.Windows.Forms.MessageBoxIcon.Error);

Alternatively, you can add at the begining of your file:

using System.Windows.Forms

and then use (as stated in previous answers):

MessageBox.Show("Some text", "Some title", 
    MessageBoxButtons.OK, MessageBoxIcon.Error);

Change bootstrap datepicker date format on select

Easy way:

Open the file bootstrap-datepicker.js

Go to line 1399 and find format: 'mm/dd/yyyy'.

Now you can change the date format here.

How to compile and run C files from within Notepad++ using NppExec plugin?

In windows if you are using a portable version of MinGW you must set path variable or you have error libintl-8.dll not found. My path is C:\Program Files (x86)\CodeBlocks\MinGW\bin

Find a value anywhere in a database

For Development purpose you can just export the required tables data into a single HTML and make a direct search on it.

Imshow: extent and aspect

From plt.imshow() official guide, we know that aspect controls the aspect ratio of the axes. Well in my words, the aspect is exactly the ratio of x unit and y unit. Most of the time we want to keep it as 1 since we do not want to distort out figures unintentionally. However, there is indeed cases that we need to specify aspect a value other than 1. The questioner provided a good example that x and y axis may have different physical units. Let's assume that x is in km and y in m. Hence for a 10x10 data, the extent should be [0,10km,0,10m] = [0, 10000m, 0, 10m]. In such case, if we continue to use the default aspect=1, the quality of the figure is really bad. We can hence specify aspect = 1000 to optimize our figure. The following codes illustrate this method.

%matplotlib inline
import numpy as np
import matplotlib.pyplot as plt
rng=np.random.RandomState(0)
data=rng.randn(10,10)
plt.imshow(data, origin = 'lower',  extent = [0, 10000, 0, 10], aspect = 1000)

enter image description here

Nevertheless, I think there is an alternative that can meet the questioner's demand. We can just set the extent as [0,10,0,10] and add additional xy axis labels to denote the units. Codes as follows.

plt.imshow(data, origin = 'lower',  extent = [0, 10, 0, 10])
plt.xlabel('km')
plt.ylabel('m')

enter image description here

To make a correct figure, we should always bear in mind that x_max-x_min = x_res * data.shape[1] and y_max - y_min = y_res * data.shape[0], where extent = [x_min, x_max, y_min, y_max]. By default, aspect = 1, meaning that the unit pixel is square. This default behavior also works fine for x_res and y_res that have different values. Extending the previous example, let's assume that x_res is 1.5 while y_res is 1. Hence extent should equal to [0,15,0,10]. Using the default aspect, we can have rectangular color pixels, whereas the unit pixel is still square!

plt.imshow(data, origin = 'lower',  extent = [0, 15, 0, 10])
# Or we have similar x_max and y_max but different data.shape, leading to different color pixel res.
data=rng.randn(10,5)
plt.imshow(data, origin = 'lower',  extent = [0, 5, 0, 5])

enter image description here enter image description here

The aspect of color pixel is x_res / y_res. setting its aspect to the aspect of unit pixel (i.e. aspect = x_res / y_res = ((x_max - x_min) / data.shape[1]) / ((y_max - y_min) / data.shape[0])) would always give square color pixel. We can change aspect = 1.5 so that x-axis unit is 1.5 times y-axis unit, leading to a square color pixel and square whole figure but rectangular pixel unit. Apparently, it is not normally accepted.

data=rng.randn(10,10)
plt.imshow(data, origin = 'lower',  extent = [0, 15, 0, 10], aspect = 1.5)

enter image description here

The most undesired case is that set aspect an arbitrary value, like 1.2, which will lead to neither square unit pixels nor square color pixels.

plt.imshow(data, origin = 'lower',  extent = [0, 15, 0, 10], aspect = 1.2)

enter image description here

Long story short, it is always enough to set the correct extent and let the matplotlib do the remaining things for us (even though x_res!=y_res)! Change aspect only when it is a must.

What is the default value for Guid?

You can use Guid.Empty. It is a read-only instance of the Guid structure with the value of 00000000-0000-0000-0000-000000000000

you can also use these instead

var g = new Guid();
var g = default(Guid);

beware not to use Guid.NewGuid() because it will generate a new Guid.

use one of the options above which you and your team think it is more readable and stick to it. Do not mix different options across the code. I think the Guid.Empty is the best one since new Guid() might make us think it is generating a new guid and some may not know what is the value of default(Guid).

pandas: to_numeric for multiple columns

If you are looking for a range of columns, you can try this:

df.iloc[7:] = df.iloc[7:].astype(float)

The examples above will convert type to be float, for all the columns begin with the 7th to the end. You of course can use different type or different range.

I think this is useful when you have a big range of columns to convert and a lot of rows. It doesn't make you go over each row by yourself - I believe numpy do it more efficiently.

This is useful only if you know that all the required columns contain numbers only - it will not change "bad values" (like string) to be NaN for you.

Add Favicon with React and Webpack

The correct answer in the present if you dont use Create React App is the next:

new HtmlWebpackPlugin({
   favicon: "./public/fav-icon.ico"
})

If you use CRA then you can modificate the manifest.json in the public directory

Simple argparse example wanted: 1 argument, 3 results

Note the Argparse Tutorial in Python HOWTOs. It starts from most basic examples, like this one:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("square", type=int,
                    help="display a square of a given number")
args = parser.parse_args()
print(args.square**2)

and progresses to less basic ones.

There is an example with predefined choice for an option, like what is asked:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("square", type=int,
                    help="display a square of a given number")
parser.add_argument("-v", "--verbosity", type=int, choices=[0, 1, 2],
                    help="increase output verbosity")
args = parser.parse_args()
answer = args.square**2
if args.verbosity == 2:
    print("the square of {} equals {}".format(args.square, answer))
elif args.verbosity == 1:
    print("{}^2 == {}".format(args.square, answer))
else:
    print(answer)

Constructors in JavaScript objects

http://www.jsoops.net/ is quite good for oop in Js. If provide private, protected, public variable and function, and also Inheritance feature. Example Code:

var ClassA = JsOops(function (pri, pro, pub)
{// pri = private, pro = protected, pub = public

    pri.className = "I am A ";

    this.init = function (var1)// constructor
    {
        pri.className += var1;
    }

    pub.getData = function ()
    {
        return "ClassA(Top=" + pro.getClassName() + ", This=" + pri.getClassName()
        + ", ID=" + pro.getClassId() + ")";
    }

    pri.getClassName = function () { return pri.className; }
    pro.getClassName = function () { return pri.className; }
    pro.getClassId = function () { return 1; }
});

var newA = new ClassA("Class");

//***Access public function
console.log(typeof (newA.getData));
// function
console.log(newA.getData());
// ClassA(Top=I am A Class, This=I am A Class, ID=1)

//***You can not access constructor, private and protected function
console.log(typeof (newA.init));            // undefined
console.log(typeof (newA.className));       // undefined
console.log(typeof (newA.pro));             // undefined
console.log(typeof (newA.getClassName));    // undefined

Using Cygwin to Compile a C program; Execution error

Regarding the cygwin1.dll not found error, a solution I have used for at least 8 years is to add the Cygwin bin directories to the end of my %PATH% in My Computer -> Properties -> Advanced -> Environment Variables. I add them to the end of the path so in my normal work, they are searched last, minimizing the possibility of conflicts (in fact, I have had no problems with conflicts in all this time).

When you invoke the Cygwin Bash Shell, those directories get prepended to the %PATH% so everything works as intended in that environment as well.

When not running in Cygwin shell, my %PATH% is:

Path=c:\opt\perl\bin; \
     ...
     C:\opt\cygwin\bin; \
     C:\opt\cygwin\usr\bin; \
     C:\opt\cygwin\usr\local\bin;

This way, for example, ActiveState Perl's perl is found first when I am not in a Cygwin Shell, but the Cygwin perl is found when I am working in the Cygwin Shell.

How to export SQL Server database to MySQL?

I had some data I had to get from mssql into mysql, had difficulty finding a solution. So what I did in the end (a bit of a long winded way to do it, but as a last resort it works) was:

  • Open the mssql database in sql server management studio express (I used 2005)
  • Open each table in turn and
  • Click the top left corner box to select whole table:

  • Copy data to clipboard (ctrl + v)

  • Open ms excel
  • Paste data from clipboard
  • Save excel file as .csv
  • Repeat the above for each table
  • You should now be able to import the data into mysql

Hope this helps

Get difference between two dates in months using Java

You can use Joda time library for Java. It would be much easier to calculate time-diff between dates with it.

Sample snippet for time-diff:

Days d = Days.daysBetween(startDate, endDate);
int days = d.getDays();

Select single item from a list

Use the FirstOrDefault selector.

var list = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };

var firstEven = list.FirstOrDefault(n => n % 2 == 0);

if (firstEven == 0)
    Console.WriteLine("no even number");
else 
    Console.WriteLine("first even number is {0}", firstEven);

Just pass in a predicate to the First or FirstOrDefault method and it'll happily go round' the list and picks the first match for you.

If there isn't a match, FirstOrDefault will returns the default value of whatever datatype the list items is.

Hope this helps :-)

How to delete an SVN project from SVN repository

It's easy to believe that deleting the whole Subversion repository requires "informing" Subversion that you're going to delete the repository. But Subversion only cares about managing a repository once it's created, not whether the repository exists or not ( if that makes sense ). It goes like this: the Subversion tools and commands are not adversely affected by just deleting your repository directory with the regular operating system utilities (like rm -R). A repository directory is not the same thing as an installed program directory, where deleting a program without uninstalling it might leave behind erratic config files or other dependencies. A repository is 100% self-contained in its directory, and deleting it is harmless (besides losing your project history). You just clean the slate to create a new Subversion repository and import your next project.

How to start IDLE (Python editor) without using the shortcut on Windows Vista?

There's a file called idle.py in your Python installation directory in Lib\idlelib\idle.py.

If you run that file with Python, then IDLE should start.

c:\Python25\pythonw.exe c:\Python25\Lib\idlelib\idle.py

How to redirect output of an entire shell script within the script itself?

Addressing the question as updated.

#...part of script without redirection...

{
    #...part of script with redirection...
} > file1 2>file2 # ...and others as appropriate...

#...residue of script without redirection...

The braces '{ ... }' provide a unit of I/O redirection. The braces must appear where a command could appear - simplistically, at the start of a line or after a semi-colon. (Yes, that can be made more precise; if you want to quibble, let me know.)

You are right that you can preserve the original stdout and stderr with the redirections you showed, but it is usually simpler for the people who have to maintain the script later to understand what's going on if you scope the redirected code as shown above.

The relevant sections of the Bash manual are Grouping Commands and I/O Redirection. The relevant sections of the POSIX shell specification are Compound Commands and I/O Redirection. Bash has some extra notations, but is otherwise similar to the POSIX shell specification.

customize Android Facebook Login button

//call Facebook onclick on your customized button on click by the following

FacebookSdk.sdkInitialize(this.getApplicationContext());

        callbackManager = CallbackManager.Factory.create();

        LoginManager.getInstance().registerCallback(callbackManager,
                new FacebookCallback<LoginResult>() {
                    @Override
                    public void onSuccess(LoginResult loginResult) {
                        Log.d("Success", "Login");

                    }

                    @Override
                    public void onCancel() {
                        Toast.makeText(MainActivity.this, "Login Cancel", Toast.LENGTH_LONG).show();
                    }

                    @Override
                    public void onError(FacebookException exception) {
                        Toast.makeText(MainActivity.this, exception.getMessage(), Toast.LENGTH_LONG).show();
                    }
                });

        setContentView(R.layout.activity_main);

        Button mycustomizeedbutton=(Button)findViewById(R.id.mycustomizeedbutton);

        mycustomizeedbutton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                  LoginManager.getInstance().logInWithReadPermissions(this, Arrays.asList("public_profile", "user_friends"));
            }
        });

    }

Only allow specific characters in textbox

    private void txtuser_KeyPress(object sender, KeyPressEventArgs e)
    {
        if (!char.IsLetter(e.KeyChar) && !char.IsWhiteSpace(e.KeyChar) && !char.IsControl(e.KeyChar))
        {
            e.Handled = true;
        }
    }

Android and Facebook share intent

I found out you can only share either Text or Image, not both using Intents. Below code shares only Image if exists, or only Text if Image does not exits. If you want to share both, you need to use Facebook SDK from here.

If you use other solution instead of below code, don't forget to specify package name com.facebook.lite as well, which is package name of Facebook Lite. I haven't test but com.facebook.orca is package name of Facebook Messenger if you want to target that too.

You can add more methods for sharing with WhatsApp, Twitter ...

public class IntentShareHelper {

    /**
     * <b>Beware,</b> this shares only image if exists, or only text if image does not exits. Can't share both
     */
    public static void shareOnFacebook(AppCompatActivity appCompatActivity, String textBody, Uri fileUri) {
        Intent intent = new Intent(Intent.ACTION_SEND);
        intent.setType("text/plain");
        intent.putExtra(Intent.EXTRA_TEXT,!TextUtils.isEmpty(textBody) ? textBody : "");

        if (fileUri != null) {
            intent.putExtra(Intent.EXTRA_STREAM, fileUri);
            intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
            intent.setType("image/*");
        }

        boolean facebookAppFound = false;
        List<ResolveInfo> matches = appCompatActivity.getPackageManager().queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);
        for (ResolveInfo info : matches) {
            if (info.activityInfo.packageName.toLowerCase().startsWith("com.facebook.katana") ||
                info.activityInfo.packageName.toLowerCase().startsWith("com.facebook.lite")) {
                intent.setPackage(info.activityInfo.packageName);
                facebookAppFound = true;
                break;
            }
        }

        if (facebookAppFound) {
            appCompatActivity.startActivity(intent);
        } else {
            showWarningDialog(appCompatActivity, appCompatActivity.getString(R.string.error_activity_not_found));
        }
    }

    public static void shareOnWhatsapp(AppCompatActivity appCompatActivity, String textBody, Uri fileUri){...}

    private static void showWarningDialog(Context context, String message) {
        new AlertDialog.Builder(context)
                .setMessage(message)
                .setNegativeButton(context.getString(R.string.close), new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                })
                .setCancelable(true)
                .create().show();
    }
}

For getting Uri from File, use below class:

public class UtilityFile {
    public static @Nullable Uri getUriFromFile(Context context, @Nullable File file) {
        if (file == null)
            return null;

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            try {
                return FileProvider.getUriForFile(context, "com.my.package.fileprovider", file);
            } catch (Exception e) {
                e.printStackTrace();
                return null;
            }
        } else {
            return Uri.fromFile(file);
        }
    }

    // Returns the URI path to the Bitmap displayed in specified ImageView       
    public static Uri getLocalBitmapUri(Context context, ImageView imageView) {
        Drawable drawable = imageView.getDrawable();
        Bitmap bmp = null;
        if (drawable instanceof BitmapDrawable) {
            bmp = ((BitmapDrawable) imageView.getDrawable()).getBitmap();
        } else {
            return null;
        }
        // Store image to default external storage directory
        Uri bmpUri = null;
        try {
            // Use methods on Context to access package-specific directories on external storage.
            // This way, you don't need to request external read/write permission.
            File file = new File(context.getExternalFilesDir(Environment.DIRECTORY_PICTURES), "share_image_" + System.currentTimeMillis() + ".png");
            FileOutputStream out = new FileOutputStream(file);
            bmp.compress(Bitmap.CompressFormat.PNG, 90, out);
            out.close();

            bmpUri = getUriFromFile(context, file);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return bmpUri;
    }    
}

For writing FileProvider, use this link: https://github.com/codepath/android_guides/wiki/Sharing-Content-with-Intents

SVN Repository Search

I started using this tool

http://www.supose.org/wiki/supose

It works fine just lacking a visual UI, but is fast and somewhat maintained

How do I find which transaction is causing a "Waiting for table metadata lock" state?

SHOW ENGINE INNODB STATUS \G

Look for the Section -

TRANSACTIONS

We can use INFORMATION_SCHEMA Tables.

Useful Queries

To check about all the locks transactions are waiting for:

USE INFORMATION_SCHEMA;
SELECT * FROM INNODB_LOCK_WAITS;

A list of blocking transactions:

SELECT * 
FROM INNODB_LOCKS 
WHERE LOCK_TRX_ID IN (SELECT BLOCKING_TRX_ID FROM INNODB_LOCK_WAITS);

OR

SELECT INNODB_LOCKS.* 
FROM INNODB_LOCKS
JOIN INNODB_LOCK_WAITS
  ON (INNODB_LOCKS.LOCK_TRX_ID = INNODB_LOCK_WAITS.BLOCKING_TRX_ID);

A List of locks on particular table:

SELECT * FROM INNODB_LOCKS 
WHERE LOCK_TABLE = db_name.table_name;

A list of transactions waiting for locks:

SELECT TRX_ID, TRX_REQUESTED_LOCK_ID, TRX_MYSQL_THREAD_ID, TRX_QUERY
FROM INNODB_TRX
WHERE TRX_STATE = 'LOCK WAIT';

Reference - MySQL Troubleshooting: What To Do When Queries Don't Work, Chapter 6 - Page 96.

java.net.ConnectException: Connection refused

I changed my DNS network and it fixed the problem

Deck of cards JAVA

I think the solution is just as simple as this:

Card temp = deck[cardAindex];
deck[cardAIndex]=deck[cardBIndex]; 
deck[cardBIndex]=temp;

Generating a Random Number between 1 and 10 Java

As the documentation says, this method call returns "a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive)". This means that you will get numbers from 0 to 9 in your case. So you've done everything correctly by adding one to that number.

Generally speaking, if you need to generate numbers from min to max (including both), you write

random.nextInt(max - min + 1) + min

Function pointer to member function

While you unfortunately cannot convert an existing member function pointer to a plain function pointer, you can create an adapter function template in a fairly straightforward way that wraps a member function pointer known at compile-time in a normal function like this:

template <class Type>
struct member_function;

template <class Type, class Ret, class... Args>
struct member_function<Ret(Type::*)(Args...)>
{
    template <Ret(Type::*Func)(Args...)>
    static Ret adapter(Type &obj, Args&&... args)
    {
        return (obj.*Func)(std::forward<Args>(args)...);
    }
};

template <class Type, class Ret, class... Args>
struct member_function<Ret(Type::*)(Args...) const>
{
    template <Ret(Type::*Func)(Args...) const>
    static Ret adapter(const Type &obj, Args&&... args)
    {
        return (obj.*Func)(std::forward<Args>(args)...);
    }
};

 

int (*func)(A&) = &member_function<decltype(&A::f)>::adapter<&A::f>;

Note that in order to call the member function, an instance of A must be provided.

How to wait in bash for several subprocesses to finish and return exit code !=0 when any subprocess ends with code !=0?

Wait for all jobs and return the exit code of the last failing job. Unlike solutions above, this does not require pid saving. Just bg away, and wait.

function wait_ex {
    # this waits for all jobs and returns the exit code of the last failing job
    ecode=0
    while true; do
        wait -n
        err="$?"
        [ "$err" == "127" ] && break
        [ "$err" != "0" ] && ecode="$err"
    done
    return $ecode
}

How do I install package.json dependencies in the current directory using npm

In my case I need to do

sudo npm install  

my project is inside /var/www so I also need to set proper permissions.

Using Python, find anagrams for a list of words

Create a dictionary of (sorted word, list of word). All the words that are in the same list are anagrams of each other.

from collections import defaultdict

def load_words(filename='/usr/share/dict/american-english'):
    with open(filename) as f:
        for word in f:
            yield word.rstrip()

def get_anagrams(source):
    d = defaultdict(list)
    for word in source:
        key = "".join(sorted(word))
        d[key].append(word)
    return d

def print_anagrams(word_source):
    d = get_anagrams(word_source)
    for key, anagrams in d.iteritems():
        if len(anagrams) > 1:
            print(key, anagrams)

word_source = load_words()
print_anagrams(word_source)

Or:

word_source = ["car", "tree", "boy", "girl", "arc"]
print_anagrams(word_source)

ERROR Error: StaticInjectorError(AppModule)[UserformService -> HttpClient]:

There are two reasons for this error

1) In the array of import if you imported HttpModule twice

enter image description here

2) If you haven't import:

import { HttpModule, JsonpModule } from '@angular/http'; 

If you want then run:

npm install @angular/http

Automatically open default email client and pre-populate content

As described by RFC 6068, mailto allows you to specify subject and body, as well as cc fields. For example:

mailto:[email protected]?subject=Subject&body=message%20goes%20here

User doesn't need to click a link if you force it to be opened with JavaScript

window.location.href = "mailto:[email protected]?subject=Subject&body=message%20goes%20here";

Be aware that there is no single, standard way in which browsers/email clients handle mailto links (e.g. subject and body fields may be discarded without a warning). Also there is a risk that popup and ad blockers, anti-virus software etc. may silently block forced opening of mailto links.

"Mixed content blocked" when running an HTTP AJAX operation in an HTTPS page

If you load a page in your browser using HTTPS, the browser will refuse to load any resources over HTTP. As you've tried, changing the API URL to have HTTPS instead of HTTP typically resolves this issue. However, your API must not allow for HTTPS connections. Because of this, you must either force HTTP on the main page or request that they allow HTTPS connections.

Note on this: The request will still work if you go to the API URL instead of attempting to load it with AJAX. This is because the browser is not loading a resource from within a secured page, instead it's loading an insecure page and it's accepting that. In order for it to be available through AJAX, though, the protocols should match.

android.view.InflateException: Binary XML file line #12: Error inflating class <unknown>

I had this problem just now and managed to figure out what it was. Was referencing a colour in my values that was causing problems. So defined it manually instead of using one from the dropdown suggestions.Then it worked!

How do I export (and then import) a Subversion repository?

If you do not have file access to the repository, I prefer rsvndump (remote Subversion repository dump) to make the dump file.

Mutex lock threads

What you need to do is to call pthread_mutex_lock to secure a mutex, like this:

pthread_mutex_lock(&mutex);

Once you do this, any other calls to pthread_mutex_lock(mutex) will not return until you call pthread_mutex_unlock in this thread. So if you try to call pthread_create, you will be able to create a new thread, and that thread will be able to (incorrectly) use the shared resource. You should call pthread_mutex_lock from within your fooAPI function, and that will cause the function to wait until the shared resource is available.

So you would have something like this:

#include <pthread.h>
#include <stdio.h>

int sharedResource = 0;
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

void* fooAPI(void* param)
{
    pthread_mutex_lock(&mutex);
    printf("Changing the shared resource now.\n");
    sharedResource = 42;
    pthread_mutex_unlock(&mutex);
    return 0;
}

int main()
{
    pthread_t thread;

    // Really not locking for any reason other than to make the point.
    pthread_mutex_lock(&mutex);
    pthread_create(&thread, NULL, fooAPI, NULL);
    sleep(1);
    pthread_mutex_unlock(&mutex);

    // Now we need to lock to use the shared resource.
    pthread_mutex_lock(&mutex);
    printf("%d\n", sharedResource);
    pthread_mutex_unlock(&mutex);
}

Edit: Using resources across processes follows this same basic approach, but you need to map the memory into your other process. Here's an example using shmem:

#include <stdio.h>
#include <unistd.h>
#include <sys/file.h>
#include <sys/mman.h>
#include <sys/wait.h>

struct shared {
    pthread_mutex_t mutex;
    int sharedResource;
};

int main()
{
    int fd = shm_open("/foo", O_CREAT | O_TRUNC | O_RDWR, 0600);
    ftruncate(fd, sizeof(struct shared));

    struct shared *p = (struct shared*)mmap(0, sizeof(struct shared),
        PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);

    p->sharedResource = 0;

    // Make sure it can be shared across processes
    pthread_mutexattr_t shared;
    pthread_mutexattr_init(&shared);
    pthread_mutexattr_setpshared(&shared, PTHREAD_PROCESS_SHARED);

    pthread_mutex_init(&(p->mutex), &shared);

    int i;
    for (i = 0; i < 100; i++) {
        pthread_mutex_lock(&(p->mutex));
        printf("%d\n", p->sharedResource);
        pthread_mutex_unlock(&(p->mutex));
        sleep(1);
    }

    munmap(p, sizeof(struct shared*));
    shm_unlink("/foo");
}

Writing the program to make changes to p->sharedResource is left as an exercise for the reader. :-)

Forgot to note, by the way, that the mutex has to have the PTHREAD_PROCESS_SHARED attribute set, so that pthreads will work across processes.

How do I select and store columns greater than a number in pandas?

Sample DF:

In [79]: df = pd.DataFrame(np.random.randint(5, 15, (10, 3)), columns=list('abc'))

In [80]: df
Out[80]:
    a   b   c
0   6  11  11
1  14   7   8
2  13   5  11
3  13   7  11
4  13   5   9
5   5  11   9
6   9   8   6
7   5  11  10
8   8  10  14
9   7  14  13

present only those rows where b > 10

In [81]: df[df.b > 10]
Out[81]:
   a   b   c
0  6  11  11
5  5  11   9
7  5  11  10
9  7  14  13

Minimums (for all columns) for the rows satisfying b > 10 condition

In [82]: df[df.b > 10].min()
Out[82]:
a     5
b    11
c     9
dtype: int32

Minimum (for the b column) for the rows satisfying b > 10 condition

In [84]: df.loc[df.b > 10, 'b'].min()
Out[84]: 11

UPDATE: starting from Pandas 0.20.1 the .ix indexer is deprecated, in favor of the more strict .iloc and .loc indexers.

What is the @Html.DisplayFor syntax for?

Html.DisplayFor() will render the DisplayTemplate that matches the property's type.

If it can't find any, I suppose it invokes .ToString().


If you don't know about display templates, they're partial views that can be put in a DisplayTemplates folder inside the view folder associated to a controller.


Example:

If you create a view named String.cshtml inside the DisplayTemplates folder of your views folder (e.g Home, or Shared) with the following code:

@model string

@if (string.IsNullOrEmpty(Model)) {
   <strong>Null string</strong>
}
else {
   @Model
}

Then @Html.DisplayFor(model => model.Title) (assuming that Title is a string) will use the template and display <strong>Null string</strong> if the string is null, or empty.

How to delete the first row of a dataframe in R?

While I agree with the most voted answer, here is another way to keep all rows except the first:

dat <- tail(dat, -1)

This can also be accomplished using Hadley Wickham's dplyr package.

dat <- dat %>% slice(-1)

Vertical rulers in Visual Studio Code

Combining the answers of kiamlaluno and Mark, along with formatOnSave to autointent code for Python:

{
    "editor.formatOnSave": true,
    "editor.autoIndent": "advanced",
    "editor.detectIndentation": true,
    "files.insertFinalNewline": true,
    "files.trimTrailingWhitespace": true,
    "editor.formatOnPaste": true,
    "editor.multiCursorModifier": "ctrlCmd",
    "editor.snippetSuggestions": "top",
    "editor.rulers": [
        {
            "column": 79,
            "color": "#424142"
        },
        100, // <- a ruler in the default color or as customized at column 0
        {
            "column": 120,
            "color": "#ff0000"
        },
    ],

}

How to get Selected Text from select2 when using <input>

In Select2 version 4 each option has the same properties of the objects in the list;

if you have the object

Obj = {
  name: "Alberas",
  description: "developer",
  birthDate: "01/01/1990"
}

then you retrieve the selected data

var data = $('#id-selected-input').select2('data');
console.log(data[0].name);
console.log(data[0].description);
console.log(data[0].birthDate);
 

R legend placement in a plot

?legend will tell you:

Arguments

x, y
the x and y co-ordinates to be used to position the legend. They can be specified by keyword or in any way which is accepted by xy.coords: See ‘Details’.

Details:

Arguments x, y, legend are interpreted in a non-standard way to allow the coordinates to be specified via one or two arguments. If legend is missing and y is not numeric, it is assumed that the second argument is intended to be legend and that the first argument specifies the coordinates.

The coordinates can be specified in any way which is accepted by xy.coords. If this gives the coordinates of one point, it is used as the top-left coordinate of the rectangle containing the legend. If it gives the coordinates of two points, these specify opposite corners of the rectangle (either pair of corners, in any order).

The location may also be specified by setting x to a single keyword from the list bottomright, bottom, bottomleft, left, topleft, top, topright, right and center. This places the legend on the inside of the plot frame at the given location. Partial argument matching is used. The optional inset argument specifies how far the legend is inset from the plot margins. If a single value is given, it is used for both margins; if two values are given, the first is used for x- distance, the second for y-distance.

Git Cherry-Pick and Conflicts

Do, I need to resolve all the conflicts before proceeding to next cherry -pick

Yes, at least with the standard git setup. You cannot cherry-pick while there are conflicts.

Furthermore, in general conflicts get harder to resolve the more you have, so it's generally better to resolve them one by one.

That said, you can cherry-pick multiple commits at once, which would do what you are asking for. See e.g. How to cherry-pick multiple commits . This is useful if for example some commits undo earlier commits. Then you'd want to cherry-pick all in one go, so you don't have to resolve conflicts for changes that are undone by later commits.

Further, is it suggested to do cherry-pick or branch merge in this case?

Generally, if you want to keep a feature branch up to date with main development, you just merge master -> feature branch. The main advantage is that a later merge feature branch -> master will be much less painful.

Cherry-picking is only useful if you must exclude some changes in master from your feature branch. Still, this will be painful so I'd try to avoid it.

What is the purpose and use of **kwargs?

kwargs are a syntactic sugar to pass name arguments as dictionaries(for func), or dictionaries as named arguments(to func)

Specifying row names when reading in a file

If you used read.table() (or one of it's ilk, e.g. read.csv()) then the easy fix is to change the call to:

read.table(file = "foo.txt", row.names = 1, ....)

where .... are the other arguments you needed/used. The row.names argument takes the column number of the data file from which to take the row names. It need not be the first column. See ?read.table for details/info.

If you already have the data in R and can't be bothered to re-read it, or it came from another route, just set the rownames attribute and remove the first variable from the object (assuming obj is your object)

rownames(obj) <- obj[, 1]  ## set rownames
obj <- obj[, -1]           ## remove the first variable

Dart: mapping a list (list.map)

Yes, You can do it this way too

 List<String> listTab = new List();
 map.forEach((key, val) {
  listTab.add(val);
 });

 //your widget//
 bottom: new TabBar(
  controller: _controller,
  isScrollable: true,
  tabs: listTab
  ,
),

What is the command to truncate a SQL Server log file?

if I remember well... in query analyzer or equivalent:

BACKUP LOG  databasename  WITH TRUNCATE_ONLY

DBCC SHRINKFILE (  databasename_Log, 1)

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

You can do

int sum = lst.stream().filter(o -> o.getField() > 10).mapToInt(o -> o.getField()).sum();

or (using Method reference)

int sum = lst.stream().filter(o -> o.getField() > 10).mapToInt(Obj::getField).sum();

How to replace an entire line in a text file by line number

I actually used this script to replace a line of code in the cron file on our company's UNIX servers awhile back. We executed it as normal shell script and had no problems:

#Create temporary file with new line in place
cat /dir/file | sed -e "s/the_original_line/the_new_line/" > /dir/temp_file
#Copy the new file over the original file
mv /dir/temp_file /dir/file

This doesn't go by line number, but you can easily switch to a line number based system by putting the line number before the s/ and placing a wildcard in place of the_original_line.

Android ACTION_IMAGE_CAPTURE Intent

I created simple library which will manage choosing images from different sources (Gallery, Camera), maybe save it to some location (SD-Card or internal memory) and return the image back so please free to use it and improve it - Android-ImageChooser.

Xcode - iPhone - profile doesn't match any valid certificate-/private-key pair in the default keychain

This also can happen if the device you are trying to run on has some older version of the provisioning profile you are using that points to an old, expired or revoked certificate or a certificate without associated private key. Delete any invalid Provisioning Profiles under your device section in Xcode organizer.

Getting the first index of an object

I had the same problem yesterday. I solved it like this:

var obj = {
        foo:{},
        bar:{},
        baz:{}
    },
   first = null,
   key = null;
for (var key in obj) {
    first = obj[key];
    if(typeof(first) !== 'function') {
        break;
    }
}
// first is the first enumerated property, and key it's corresponding key.

Not the most elegant solution, and I am pretty sure that it may yield different results in different browsers (i.e. the specs says that enumeration is not required to enumerate the properties in the same order as they were defined). However, I only had a single property in my object so that was a non-issue. I just needed the first key.

Disable output buffering

You can also use fcntl to change the file flags in-fly.

fl = fcntl.fcntl(fd.fileno(), fcntl.F_GETFL)
fl |= os.O_SYNC # or os.O_DSYNC (if you don't care the file timestamp updates)
fcntl.fcntl(fd.fileno(), fcntl.F_SETFL, fl)

Using cURL with a username and password?

I had the same need in bash (Ubuntu 16.04 LTS) and the commands provided in the answers failed to work in my case. I had to use:

curl -X POST -F 'username="$USER"' -F 'password="$PASS"' "http://api.somesite.com/test/blah?something=123"

Double quotes in the -F arguments are only needed if you're using variables, thus from the command line ... -F 'username=myuser' ... will be fine.

Relevant Security Notice: as Mr. Mark Ribau points in comments this command shows the password ($PASS variable, expanded) in the processlist!

How can I pass a username/password in the header to a SOAP WCF Service

I added customBinding to the web.config.

<configuration>
  <system.serviceModel>
    <bindings>
      <customBinding>
        <binding name="CustomSoapBinding">
          <security includeTimestamp="false"
                    authenticationMode="UserNameOverTransport"
                    defaultAlgorithmSuite="Basic256"
                    requireDerivedKeys="false"
                    messageSecurityVersion="WSSecurity10WSTrustFebruary2005WSSecureConversationFebruary2005WSSecurityPolicy11BasicSecurityProfile10">
          </security>
          <textMessageEncoding messageVersion="Soap11"></textMessageEncoding>
          <httpsTransport maxReceivedMessageSize="2000000000"/>
        </binding>
      </customBinding>
    </bindings>
    <client>
      <endpoint address="https://test.com:443/services/testService"
                binding="customBinding"
                bindingConfiguration="CustomSoapBinding"
                contract="testService.test"
                name="test" />
    </client>
  </system.serviceModel>
  <startup>
    <supportedRuntime version="v4.0"
                      sku=".NETFramework,Version=v4.0"/>
  </startup>
</configuration>

After adding customBinding, I can pass username and password to client service like as follows:

service.ClientCridentials.UserName.UserName = "testUser";
service.ClientCridentials.UserName.Password = "testPass";

In this way you can pass username, password in the header to a SOAP WCF Service.

How is malloc() implemented internally?

The sbrksystem call moves the "border" of the data segment. This means it moves a border of an area in which a program may read/write data (letting it grow or shrink, although AFAIK no malloc really gives memory segments back to the kernel with that method). Aside from that, there's also mmap which is used to map files into memory but is also used to allocate memory (if you need to allocate shared memory, mmap is how you do it).

So you have two methods of getting more memory from the kernel: sbrk and mmap. There are various strategies on how to organize the memory that you've got from the kernel.

One naive way is to partition it into zones, often called "buckets", which are dedicated to certain structure sizes. For example, a malloc implementation could create buckets for 16, 64, 256 and 1024 byte structures. If you ask malloc to give you memory of a given size it rounds that number up to the next bucket size and then gives you an element from that bucket. If you need a bigger area malloc could use mmap to allocate directly with the kernel. If the bucket of a certain size is empty malloc could use sbrk to get more space for a new bucket.

There are various malloc designs and there is propably no one true way of implementing malloc as you need to make a compromise between speed, overhead and avoiding fragmentation/space effectiveness. For example, if a bucket runs out of elements an implementation might get an element from a bigger bucket, split it up and add it to the bucket that ran out of elements. This would be quite space efficient but would not be possible with every design. If you just get another bucket via sbrk/mmap that might be faster and even easier, but not as space efficient. Also, the design must of course take into account that "free" needs to make space available to malloc again somehow. You don't just hand out memory without reusing it.

If you're interested, the OpenSER/Kamailio SIP proxy has two malloc implementations (they need their own because they make heavy use of shared memory and the system malloc doesn't support shared memory). See: https://github.com/OpenSIPS/opensips/tree/master/mem

Then you could also have a look at the GNU libc malloc implementation, but that one is very complicated, IIRC.

Two dimensional array in python

the above method did not work for me for a for loop, where I wanted to transfer data from a 2D array to a new array under an if the condition. This method would work

a_2d_list = [[1, 2], [3, 4]]
a_2d_list.append([5, 6])
print(a_2d_list)

OUTPUT - [[1, 2], [3, 4], [5, 6]]

MySql sum elements of a column

select
  sum(a) as atotal,
  sum(b) as btotal,
  sum(c) as ctotal
from
  yourtable t
where
  t.id in (1, 2, 3)

How to Update/Drop a Hive Partition?

Alter table table_name drop partition (partition_name);

Android: Scale a Drawable or background image?

To customize background image scaling create a resource like this:

<?xml version="1.0" encoding="utf-8"?>
<bitmap xmlns:android="http://schemas.android.com/apk/res/android"
    android:gravity="center"
    android:src="@drawable/list_bkgnd" />

Then it will be centered in the view if used as background. There are also other flags: http://developer.android.com/guide/topics/resources/drawable-resource.html

"No Content-Security-Policy meta tag found." error in my phonegap application

You have to add a CSP meta tag in the head section of your app's index.html

As per https://github.com/apache/cordova-plugin-whitelist#content-security-policy

Content Security Policy

Controls which network requests (images, XHRs, etc) are allowed to be made (via webview directly).

On Android and iOS, the network request whitelist (see above) is not able to filter all types of requests (e.g. <video> & WebSockets are not blocked). So, in addition to the whitelist, you should use a Content Security Policy <meta> tag on all of your pages.

On Android, support for CSP within the system webview starts with KitKat (but is available on all versions using Crosswalk WebView).

Here are some example CSP declarations for your .html pages:

<!-- Good default declaration:
    * gap: is required only on iOS (when using UIWebView) and is needed for JS->native communication
    * https://ssl.gstatic.com is required only on Android and is needed for TalkBack to function properly
    * Disables use of eval() and inline scripts in order to mitigate risk of XSS vulnerabilities. To change this:
        * Enable inline JS: add 'unsafe-inline' to default-src
        * Enable eval(): add 'unsafe-eval' to default-src
-->
<meta http-equiv="Content-Security-Policy" content="default-src 'self' data: gap: https://ssl.gstatic.com; style-src 'self' 'unsafe-inline'; media-src *">

<!-- Allow requests to foo.com -->
<meta http-equiv="Content-Security-Policy" content="default-src 'self' foo.com">

<!-- Enable all requests, inline styles, and eval() -->
<meta http-equiv="Content-Security-Policy" content="default-src *; style-src 'self' 'unsafe-inline'; script-src 'self' 'unsafe-inline' 'unsafe-eval'">

<!-- Allow XHRs via https only -->
<meta http-equiv="Content-Security-Policy" content="default-src 'self' https:">

<!-- Allow iframe to https://cordova.apache.org/ -->
<meta http-equiv="Content-Security-Policy" content="default-src 'self'; frame-src 'self' https://cordova.apache.org">

PHP - how to create a newline character?

You should use this:

"\n"

You also might wanna have a look at PHP EOL.

Exception in thread "main" java.lang.Error: Unresolved compilation problems

Your problem is in this line: Message messageObject = new Message ();
This error says that the Message class is not known at compile time.

So you need to import the Message class.

Something like this:

import package1.package2.Message;

Check this out.

http://docs.oracle.com/javase/tutorial/java/package/usepkgs.html

Configuring angularjs with eclipse IDE

Hi Guys if u are using angular plugin in eclipse that time is plugin is limited periods after that if u want to used this plugin then u pay it so i suggest to you used webstrome and visual code ide that are very easy and comfort to used so take care if u start and developed a angular app using eclipse

SQLiteDatabase.query method

This is a more general answer meant to be a quick reference for future viewers.

Example

SQLiteDatabase db = helper.getReadableDatabase();

String table = "table2";
String[] columns = {"column1", "column3"};
String selection = "column3 =?";
String[] selectionArgs = {"apple"};
String groupBy = null;
String having = null;
String orderBy = "column3 DESC";
String limit = "10";

Cursor cursor = db.query(table, columns, selection, selectionArgs, groupBy, having, orderBy, limit);

Explanation from the documentation

  • table String: The table name to compile the query against.
  • columns String: A list of which columns to return. Passing null will return all columns, which is discouraged to prevent reading data from storage that isn't going to be used.
  • selection String: A filter declaring which rows to return, formatted as an SQL WHERE clause (excluding the WHERE itself). Passing null will return all rows for the given table.
  • selectionArgs String: You may include ?s in selection, which will be replaced by the values from selectionArgs, in order that they appear in the selection. The values will be bound as Strings.
  • groupBy String: A filter declaring how to group rows, formatted as an SQL GROUP BY clause (excluding the GROUP BY itself). Passing null will cause the rows to not be grouped.
  • having String: A filter declare which row groups to include in the cursor, if row grouping is being used, formatted as an SQL HAVING clause (excluding the HAVING itself). Passing null will cause all row groups to be included, and is required when row grouping is not being used.
  • orderBy String: How to order the rows, formatted as an SQL ORDER BY clause (excluding the ORDER BY itself). Passing null will use the default sort order, which may be unordered.
  • limit String: Limits the number of rows returned by the query, formatted as LIMIT clause. Passing null denotes no LIMIT clause.

What does the 'u' symbol mean in front of string values?

The 'u' in front of the string values means the string is a Unicode string. Unicode is a way to represent more characters than normal ASCII can manage. The fact that you're seeing the u means you're on Python 2 - strings are Unicode by default on Python 3, but on Python 2, the u in front distinguishes Unicode strings. The rest of this answer will focus on Python 2.

You can create a Unicode string multiple ways:

>>> u'foo'
u'foo'
>>> unicode('foo') # Python 2 only
u'foo'

But the real reason is to represent something like this (translation here):

>>> val = u'???????????? ? ?????????????'
>>> val
u'\u041e\u0437\u043d\u0430\u043a\u043e\u043c\u044c\u0442\u0435\u0441\u044c \u0441 \u0434\u043e\u043a\u0443\u043c\u0435\u043d\u0442\u0430\u0446\u0438\u0435\u0439'
>>> print val
???????????? ? ?????????????

For the most part, Unicode and non-Unicode strings are interoperable on Python 2.

There are other symbols you will see, such as the "raw" symbol r for telling a string not to interpret backslashes. This is extremely useful for writing regular expressions.

>>> 'foo\"'
'foo"'
>>> r'foo\"'
'foo\\"'

Unicode and non-Unicode strings can be equal on Python 2:

>>> bird1 = unicode('unladen swallow')
>>> bird2 = 'unladen swallow'
>>> bird1 == bird2
True

but not on Python 3:

>>> x = u'asdf' # Python 3
>>> y = b'asdf' # b indicates bytestring
>>> x == y
False

Python: Generate random number between x and y which is a multiple of 5

The simplest way is to generate a random nuber between 0-1 then strech it by multiplying, and shifting it.
So yo would multiply by (x-y) so the result is in the range of 0 to x-y,
Then add x and you get the random number between x and y.

To get a five multiplier use rounding. If this is unclear let me know and I'll add code snippets.

Styling a disabled input with css only

Let's just say you have 3 buttons:

<input type="button" disabled="disabled" value="hello world">
<input type="button" disabled value="hello world">
<input type="button" value="hello world">

To style the disabled button you can use the following css:

input[type="button"]:disabled{
    color:#000;
}

This will only affect the button which is disabled.

To stop the color changing when hovering you can use this too:

input[type="button"]:disabled:hover{
    color:#000;
}

You can also avoid this by using a css-reset.

How can I use Helvetica Neue Condensed Bold in CSS?

After a lot of fiddling, got it working (only tested in Webkit) using:

font-family: "HelveticaNeue-CondensedBold";

font-stretch was dropped between CSS2 and 2.1, though is back in CSS3, but is only supported in IE9 (never thought I'd be able to say that about any CSS prop!)

This works because I'm using the postscript name (find the font in Font Book, hit cmd+I), which is non-standard behaviour. It's probably worth using:

font-family: "HelveticaNeue-CondensedBold", "Helvetica Neue";

As a fallback, else other browsers might default to serif if they can't work it out.

Demo: http://jsfiddle.net/ndFTL/12/

Convert a timedelta to days, hours and minutes

I found the easiest way is using str(timedelta). It will return a sting formatted like 3 days, 21:06:40.001000, and you can parse hours and minutes using simple string operations or regular expression.

permission denied - php unlink

in addition to all the answers that other friends have , if somebody who is looking this post is looking for a way to delete a "Folder" not a "file" , should take care that Folders must delete by php rmdir() function and if u want to delete a "Folder" by unlink() , u will encounter with a wrong Warning message that says "permission denied"

however u can make folders & files by mkdir() but the way u delete folders (rmdir()) is different from the way you delete files(unlink())

eventually as a fact:

in many programming languages, any permission related error may not directly means an actual permission issue

for example, if you want to readSync a file that doesn't exist with node fs module you will encounter a wrong EPERM error

Error in contrasts when defining a linear model in R

If the error happens to be because your data has NAs, then you need to set the glm() function options of how you would like to treat the NA cases. More information on this is found in a relevant post here: https://stats.stackexchange.com/questions/46692/how-the-na-values-are-treated-in-glm-in-r

TransactionRequiredException Executing an update/delete query

Just add @Transactional on method level or class level. When you are updating or deleting record/s you have to maintain persistence state of Transaction and @Transactional manages this.

and import org.springframework.transaction.annotation.Transactional;

How do I extract text that lies between parentheses (round brackets)?

This code is faster than most solutions here (if not all), packed as String extension method, it does not support recursive nesting:

public static string GetNestedString(this string str, char start, char end)
{
    int s = -1;
    int i = -1;
    while (++i < str.Length)
        if (str[i] == start)
        {
            s = i;
            break;
        }
    int e = -1;
    while(++i < str.Length)
        if (str[i] == end)
        {
            e = i;
            break;
        }
    if (e > s)
        return str.Substring(s + 1, e - s - 1);
    return null;
}

This one is little longer and slower, but it handles recursive nesting more nicely:

public static string GetNestedString(this string str, char start, char end)
{
    int s = -1;
    int i = -1;
    while (++i < str.Length)
        if (str[i] == start)
        {
            s = i;
            break;
        }
    int e = -1;
    int depth = 0;
    while (++i < str.Length)
        if (str[i] == end)
        {
            e = i;
            if (depth == 0)
                break;
            else
                --depth;
        }
        else if (str[i] == start)
            ++depth;
    if (e > s)
        return str.Substring(s + 1, e - s - 1);
    return null;
}

Updating a java map entry

If key is present table.put(key, val) will just overwrite the value else it'll create a new entry. Poof! and you are done. :)

you can get the value from a map by using key is table.get(key); That's about it

IE prompts to open or save json result from server

I changed the content-type to "text/html" instead of "application/json" server side before returning the response. Described it in a blog post, where other solutions have also been added:

http://blog.degree.no/2012/09/jquery-json-ie8ie9-treats-response-as-downloadable-file/

twitter bootstrap 3.0 typeahead ajax example

Here is my step by step experience, inspired by typeahead examples, from a Scala/PlayFramework app we are working on.

In a script LearnerNameTypeAhead.coffee (convertible of course to JS) I have:

$ ->
  learners = new Bloodhound(
    datumTokenizer: Bloodhound.tokenizers.obj.whitespace("value")
    queryTokenizer: Bloodhound.tokenizers.whitespace
    remote: "/learner/namelike?nameLikeStr=%QUERY"
  )
  learners.initialize()
  $("#firstName").typeahead 
    minLength: 3
    hint: true
    highlight:true
   ,
    name: "learners"
    displayKey: "value"
    source: learners.ttAdapter()

I included the typeahead bundle and my script on the page, and there is a div around my input field as follows:

<script [email protected]("javascripts/typeahead.bundle.js")></script>
<script [email protected]("javascripts/LearnerNameTypeAhead.js") type="text/javascript" ></script>
<div>
  <input name="firstName" id="firstName" class="typeahead" placeholder="First Name" value="@firstName">
</div>

The result is that for each character typed in the input field after the first minLength (3) characters, the page issues a GET request with a URL looking like /learner/namelike?nameLikeStr= plus the currently typed characters. The server code returns a json array of objects containing fields "id" and "value", for example like this:

[ {
    "id": "109",
    "value": "Graham Jones"
  },
  {
    "id": "5833",
    "value": "Hezekiah Jones"
} ]

For play I need something in the routes file:

GET /learner/namelike controllers.Learners.namesLike(nameLikeStr:String)

And finally, I set some of the styling for the dropdown, etc. in a new typeahead.css file which I included in the page's <head> (or accessible .css)

.tt-dropdown-menu {
  width: 252px;
  margin-top: 12px;
  padding: 8px 0;
  background-color: #fff;
  border: 1px solid #ccc;
  border: 1px solid rgba(0, 0, 0, 0.2);
  -webkit-border-radius: 8px;
     -moz-border-radius: 8px;
          border-radius: 8px;
  -webkit-box-shadow: 0 5px 10px rgba(0,0,0,.2);
     -moz-box-shadow: 0 5px 10px rgba(0,0,0,.2);
          box-shadow: 0 5px 10px rgba(0,0,0,.2);
}
.typeahead {
  background-color: #fff;
}
.typeahead:focus {
  border: 2px solid #0097cf;
}
.tt-query {
  -webkit-box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075);
     -moz-box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075);
          box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075);
}
.tt-hint {
  color: #999
}
.tt-suggestion {
  padding: 3px 20px;
  font-size: 18px;
  line-height: 24px;
}
.tt-suggestion.tt-cursor {
  color: #fff;
  background-color: #0097cf;
}
.tt-suggestion p {
  margin: 0;
}

How to return a file (FileContentResult) in ASP.NET WebAPI

This question helped me.

So, try this:

Controller code:

[HttpGet]
public HttpResponseMessage Test()
{
    var path = System.Web.HttpContext.Current.Server.MapPath("~/Content/test.docx");;
    HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
    var stream = new FileStream(path, FileMode.Open);
    result.Content = new StreamContent(stream);
    result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");
    result.Content.Headers.ContentDisposition.FileName = Path.GetFileName(path);
    result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
    result.Content.Headers.ContentLength = stream.Length;
    return result;          
}

View Html markup (with click event and simple url):

<script type="text/javascript">
    $(document).ready(function () {
        $("#btn").click(function () {
            // httproute = "" - using this to construct proper web api links.
            window.location.href = "@Url.Action("GetFile", "Data", new { httproute = "" })";
        });
    });
</script>


<button id="btn">
    Button text
</button>

<a href=" @Url.Action("GetFile", "Data", new { httproute = "" }) ">Data</a>

How to delete mysql database through shell command

Try the following command:

mysqladmin -h[hostname/localhost] -u[username] -p[password] drop [database]

Is a slash ("/") equivalent to an encoded slash ("%2F") in the path portion of an HTTP URL

encodeURI()/decodeURI and encodeURIComponent()/decodeURIComponent are utility functions to handle this. Read more here https://stackabuse.com/javascripts-encodeuri-function/

How to use setInterval and clearInterval?

I used angular with electron,

In my case, setInterval returns a Nodejs Timer object. which when I called clearInterval(timerobject) it did not work.

I had to get the id first and call to clearInterval

clearInterval(timerobject._id)

I have struggled many hours with this. hope this helps.

How to handle an IF STATEMENT in a Mustache template?

Just took a look over the mustache docs and they support "inverted sections" in which they state

they (inverted sections) will be rendered if the key doesn't exist, is false, or is an empty list

http://mustache.github.io/mustache.5.html#Inverted-Sections

{{#value}}
  value is true
{{/value}}
{{^value}}
  value is false
{{/value}}

How can I get a vertical scrollbar in my ListBox?

I was having the same problem, I had a ComboBox followed by a ListBox in a StackPanel and the scroll bar for the ListBox was not showing up. I solved this by putting the two in a DockPanel instead. I set the ComboBox DockPanel.Dock="Top" and let the ListBox fill the remaining space.

Access camera from a browser

Video Tutorial: Accessing the Camera with HTML5 & appMobi API will be helpful for you.

Also, you may try the getUserMedia method (supported by Opera 12)

enter image description here

How do I reflect over the members of dynamic object?

There are several scenarios to consider. First of all, you need to check the type of your object. You can simply call GetType() for this. If the type does not implement IDynamicMetaObjectProvider, then you can use reflection same as for any other object. Something like:

var propertyInfo = test.GetType().GetProperties();

However, for IDynamicMetaObjectProvider implementations, the simple reflection doesn't work. Basically, you need to know more about this object. If it is ExpandoObject (which is one of the IDynamicMetaObjectProvider implementations), you can use the answer provided by itowlson. ExpandoObject stores its properties in a dictionary and you can simply cast your dynamic object to a dictionary.

If it's DynamicObject (another IDynamicMetaObjectProvider implementation), then you need to use whatever methods this DynamicObject exposes. DynamicObject isn't required to actually "store" its list of properties anywhere. For example, it might do something like this (I'm reusing an example from my blog post):

public class SampleObject : DynamicObject
{
    public override bool TryGetMember(GetMemberBinder binder, out object result)
    {
        result = binder.Name;
        return true;
    }
}

In this case, whenever you try to access a property (with any given name), the object simply returns the name of the property as a string.

dynamic obj = new SampleObject();
Console.WriteLine(obj.SampleProperty);
//Prints "SampleProperty".

So, you don't have anything to reflect over - this object doesn't have any properties, and at the same time all valid property names will work.

I'd say for IDynamicMetaObjectProvider implementations, you need to filter on known implementations where you can get a list of properties, such as ExpandoObject, and ignore (or throw an exception) for the rest.

Create a CSV File for a user in PHP

Hey It works very well....!!!! Thanks Peter Mortensen and Connor Burton

<?php
header("Content-type: application/csv");
header("Content-Disposition: attachment; filename=file.csv");
header("Pragma: no-cache");
header("Expires: 0");

ini_set('display_errors',1);
$private=1;
error_reporting(E_ALL ^ E_NOTICE);

mysql_connect("localhost", "user", "pass") or die(mysql_error());
mysql_select_db("db") or die(mysql_error());

$start = $_GET["start"];
$end = $_GET["end"];

$query = "SELECT * FROM customers WHERE created>='{$start} 00:00:00'  AND created<='{$end} 23:59:59'   ORDER BY id";
$select_c = mysql_query($query) or die(mysql_error());

while ($row = mysql_fetch_array($select_c, MYSQL_ASSOC))
{
    $result.="{$row['email']},";
    $result.="\n";
    echo $result;
}

?>

Convert a string to a double - is this possible?

Why is floatval the best option for financial comparison data? bc functions only accurately turn strings into real numbers.

How to alias a table in Laravel Eloquent queries (or using Query Builder)?

Same as AMIB answer, for soft delete error "Unknown column 'table_alias.deleted_at'", just add ->withTrashed() then handle it yourself like ->whereRaw('items_alias.deleted_at IS NULL')

Configure apache to listen on port other than 80

It was a firewall issue. There was a hardware firewall that was blocking access to almost all ports. (Turning off software firewall / SELinux bla bla had no effect)

Then I scanned the open ports and used the port that was open.

If you are facing the same problem, Run the following command

sudo nmap -T Aggressive -A -v 127.0.0.1 -p 1-65000

It will scan for all the open ports on your system. Any port that is open can be accessed from outside.

Ref.: http://www.go2linux.org/which_service_or_program_is_listening_on_port

LINQ order by null column where order is ascending and nulls should be last

my decision:

Array = _context.Products.OrderByDescending(p => p.Val ?? float.MinValue)

Storing C++ template function definitions in a .CPP file

This should work fine everywhere templates are supported. Explicit template instantiation is part of the C++ standard.

Excel formula to search if all cells in a range read "True", if not, then show "False"

=IF(COUNTIF(A1:D1,FALSE)>0,FALSE,TRUE)

(or you can specify any other range to look in)

Easy way to get a test file into JUnit

I know you said you didn't want to read the file in by hand, but this is pretty easy

public class FooTest
{
    private BufferedReader in = null;

    @Before
    public void setup()
        throws IOException
    {
        in = new BufferedReader(
            new InputStreamReader(getClass().getResourceAsStream("/data.txt")));
    }

    @After
    public void teardown()
        throws IOException
    {
        if (in != null)
        {
            in.close();
        }

        in = null;
    }

    @Test
    public void testFoo()
        throws IOException
    {
        String line = in.readLine();

        assertThat(line, notNullValue());
    }
}

All you have to do is ensure the file in question is in the classpath. If you're using Maven, just put the file in src/test/resources and Maven will include it in the classpath when running your tests. If you need to do this sort of thing a lot, you could put the code that opens the file in a superclass and have your tests inherit from that.

Mutex example / tutorial?

While a mutex may be used to solve other problems, the primary reason they exist is to provide mutual exclusion and thereby solve what is known as a race condition. When two (or more) threads or processes are attempting to access the same variable concurrently, we have potential for a race condition. Consider the following code

//somewhere long ago, we have i declared as int
void my_concurrently_called_function()
{
  i++;
}

The internals of this function look so simple. It's only one statement. However, a typical pseudo-assembly language equivalent might be:

load i from memory into a register
add 1 to i
store i back into memory

Because the equivalent assembly-language instructions are all required to perform the increment operation on i, we say that incrementing i is a non-atmoic operation. An atomic operation is one that can be completed on the hardware with a gurantee of not being interrupted once the instruction execution has begun. Incrementing i consists of a chain of 3 atomic instructions. In a concurrent system where several threads are calling the function, problems arise when a thread reads or writes at the wrong time. Imagine we have two threads running simultaneoulsy and one calls the function immediately after the other. Let's also say that we have i initialized to 0. Also assume that we have plenty of registers and that the two threads are using completely different registers, so there will be no collisions. The actual timing of these events may be:

thread 1 load 0 into register from memory corresponding to i //register is currently 0
thread 1 add 1 to a register //register is now 1, but not memory is 0
thread 2 load 0 into register from memory corresponding to i
thread 2 add 1 to a register //register is now 1, but not memory is 0
thread 1 write register to memory //memory is now 1
thread 2 write register to memory //memory is now 1

What's happened is that we have two threads incrementing i concurrently, our function gets called twice, but the outcome is inconsistent with that fact. It looks like the function was only called once. This is because the atomicity is "broken" at the machine level, meaning threads can interrupt each other or work together at the wrong times.

We need a mechanism to solve this. We need to impose some ordering to the instructions above. One common mechanism is to block all threads except one. Pthread mutex uses this mechanism.

Any thread which has to execute some lines of code which may unsafely modify shared values by other threads at the same time (using the phone to talk to his wife), should first be made acquire a lock on a mutex. In this way, any thread that requires access to the shared data must pass through the mutex lock. Only then will a thread be able to execute the code. This section of code is called a critical section.

Once the thread has executed the critical section, it should release the lock on the mutex so that another thread can acquire a lock on the mutex.

The concept of having a mutex seems a bit odd when considering humans seeking exclusive access to real, physical objects but when programming, we must be intentional. Concurrent threads and processes don't have the social and cultural upbringing that we do, so we must force them to share data nicely.

So technically speaking, how does a mutex work? Doesn't it suffer from the same race conditions that we mentioned earlier? Isn't pthread_mutex_lock() a bit more complex that a simple increment of a variable?

Technically speaking, we need some hardware support to help us out. The hardware designers give us machine instructions that do more than one thing but are guranteed to be atomic. A classic example of such an instruction is the test-and-set (TAS). When trying to acquire a lock on a resource, we might use the TAS might check to see if a value in memory is 0. If it is, that would be our signal that the resource is in use and we do nothing (or more accurately, we wait by some mechanism. A pthreads mutex will put us into a special queue in the operating system and will notify us when the resource becomes available. Dumber systems may require us to do a tight spin loop, testing the condition over and over). If the value in memory is not 0, the TAS sets the location to something other than 0 without using any other instructions. It's like combining two assembly instructions into 1 to give us atomicity. Thus, testing and changing the value (if changing is appropriate) cannot be interrupted once it has begun. We can build mutexes on top of such an instruction.

Note: some sections may appear similar to an earlier answer. I accepted his invite to edit, he preferred the original way it was, so I'm keeping what I had which is infused with a little bit of his verbiage.

Close a div by clicking outside

 //for closeing the popover when user click outside it will close all popover 
 var hidePopover = function(element) {
        var elementScope = angular.element($(element).siblings('.popover')).scope().$parent;
        elementScope.isOpen = false;
        elementScope.$apply();
        //Remove the popover element from the DOM
        $(element).siblings('.popover').remove();
    };
 $(document).ready(function(){
 $('body').on('click', function (e) {
       $("a").each(function () {
                    //Only do this for all popovers other than the current one that cause this event
           if (!($(this).is(e.target) || $(this).has(e.target).length > 0) 
                && $(this).siblings('.popover').length !== 0 && $(this).siblings('.popover').has(e.target).length === 0)                  
                    {
                         hidePopover(this);
                    }
        });
    });
 });

Java: Getting a substring from a string starting after a particular character

Another way is to use this.

String path = "/abc/def/ghfj.doc"
String fileName = StringUtils.substringAfterLast(path, "/");

If you pass null to this method it will return null. If there is no match with separator it will return empty string.

How to detect if multiple keys are pressed at once using JavaScript?

Make the keydown even call multiple functions, with each function checking for a specific key and responding appropriately.

document.keydown = function (key) {

    checkKey("x");
    checkKey("y");
};

Adding a slide effect to bootstrap dropdown

If you update to Bootstrap 3 (BS3), they've exposed a lot of Javascript events that are nice to tie your desired functionality into. In BS3, this code will give all of your dropdown menus the animation effect you are looking for:

  // Add slideDown animation to Bootstrap dropdown when expanding.
  $('.dropdown').on('show.bs.dropdown', function() {
    $(this).find('.dropdown-menu').first().stop(true, true).slideDown();
  });

  // Add slideUp animation to Bootstrap dropdown when collapsing.
  $('.dropdown').on('hide.bs.dropdown', function() {
    $(this).find('.dropdown-menu').first().stop(true, true).slideUp();
  });

You can read about BS3 events here and specifically about the dropdown events here.

Typing Greek letters etc. in Python plots

Python 3.x: small greek letters are coded from 945 to 969 so,alpha is chr(945), omega is chr(969) so just type

print(chr(945))

the list of small greek letters in a list:

greek_letterz=[chr(code) for code in range(945,970)]

print(greek_letterz)

And now, alpha is greek_letterz[0], beta is greek_letterz[1], a.s.o

How to provide a file download from a JSF backing bean?

Introduction

You can get everything through ExternalContext. In JSF 1.x, you can get the raw HttpServletResponse object by ExternalContext#getResponse(). In JSF 2.x, you can use the bunch of new delegate methods like ExternalContext#getResponseOutputStream() without the need to grab the HttpServletResponse from under the JSF hoods.

On the response, you should set the Content-Type header so that the client knows which application to associate with the provided file. And, you should set the Content-Length header so that the client can calculate the download progress, otherwise it will be unknown. And, you should set the Content-Disposition header to attachment if you want a Save As dialog, otherwise the client will attempt to display it inline. Finally just write the file content to the response output stream.

Most important part is to call FacesContext#responseComplete() to inform JSF that it should not perform navigation and rendering after you've written the file to the response, otherwise the end of the response will be polluted with the HTML content of the page, or in older JSF versions, you will get an IllegalStateException with a message like getoutputstream() has already been called for this response when the JSF implementation calls getWriter() to render HTML.

Turn off ajax / don't use remote command!

You only need to make sure that the action method is not called by an ajax request, but that it is called by a normal request as you fire with <h:commandLink> and <h:commandButton>. Ajax requests and remote commands are handled by JavaScript which in turn has, due to security reasons, no facilities to force a Save As dialogue with the content of the ajax response.

In case you're using e.g. PrimeFaces <p:commandXxx>, then you need to make sure that you explicitly turn off ajax via ajax="false" attribute. In case you're using ICEfaces, then you need to nest a <f:ajax disabled="true" /> in the command component.

Generic JSF 2.x example

public void download() throws IOException {
    FacesContext fc = FacesContext.getCurrentInstance();
    ExternalContext ec = fc.getExternalContext();

    ec.responseReset(); // Some JSF component library or some Filter might have set some headers in the buffer beforehand. We want to get rid of them, else it may collide.
    ec.setResponseContentType(contentType); // Check http://www.iana.org/assignments/media-types for all types. Use if necessary ExternalContext#getMimeType() for auto-detection based on filename.
    ec.setResponseContentLength(contentLength); // Set it with the file size. This header is optional. It will work if it's omitted, but the download progress will be unknown.
    ec.setResponseHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\""); // The Save As popup magic is done here. You can give it any file name you want, this only won't work in MSIE, it will use current request URL as file name instead.

    OutputStream output = ec.getResponseOutputStream();
    // Now you can write the InputStream of the file to the above OutputStream the usual way.
    // ...

    fc.responseComplete(); // Important! Otherwise JSF will attempt to render the response which obviously will fail since it's already written with a file and closed.
}

Generic JSF 1.x example

public void download() throws IOException {
    FacesContext fc = FacesContext.getCurrentInstance();
    HttpServletResponse response = (HttpServletResponse) fc.getExternalContext().getResponse();

    response.reset(); // Some JSF component library or some Filter might have set some headers in the buffer beforehand. We want to get rid of them, else it may collide.
    response.setContentType(contentType); // Check http://www.iana.org/assignments/media-types for all types. Use if necessary ServletContext#getMimeType() for auto-detection based on filename.
    response.setContentLength(contentLength); // Set it with the file size. This header is optional. It will work if it's omitted, but the download progress will be unknown.
    response.setHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\""); // The Save As popup magic is done here. You can give it any file name you want, this only won't work in MSIE, it will use current request URL as file name instead.

    OutputStream output = response.getOutputStream();
    // Now you can write the InputStream of the file to the above OutputStream the usual way.
    // ...

    fc.responseComplete(); // Important! Otherwise JSF will attempt to render the response which obviously will fail since it's already written with a file and closed.
}

Common static file example

In case you need to stream a static file from the local disk file system, substitute the code as below:

File file = new File("/path/to/file.ext");
String fileName = file.getName();
String contentType = ec.getMimeType(fileName); // JSF 1.x: ((ServletContext) ec.getContext()).getMimeType(fileName);
int contentLength = (int) file.length();

// ...

Files.copy(file.toPath(), output);

Common dynamic file example

In case you need to stream a dynamically generated file, such as PDF or XLS, then simply provide output there where the API being used expects an OutputStream.

E.g. iText PDF:

String fileName = "dynamic.pdf";
String contentType = "application/pdf";

// ...

Document document = new Document();
PdfWriter writer = PdfWriter.getInstance(document, output);
document.open();
// Build PDF content here.
document.close();

E.g. Apache POI HSSF:

String fileName = "dynamic.xls";
String contentType = "application/vnd.ms-excel";

// ...

HSSFWorkbook workbook = new HSSFWorkbook();
// Build XLS content here.
workbook.write(output);
workbook.close();

Note that you cannot set the content length here. So you need to remove the line to set response content length. This is technically no problem, the only disadvantage is that the enduser will be presented an unknown download progress. In case this is important, then you really need to write to a local (temporary) file first and then provide it as shown in previous chapter.

Utility method

If you're using JSF utility library OmniFaces, then you can use one of the three convenient Faces#sendFile() methods taking either a File, or an InputStream, or a byte[], and specifying whether the file should be downloaded as an attachment (true) or inline (false).

public void download() throws IOException {
    Faces.sendFile(file, true);
}

Yes, this code is complete as-is. You don't need to invoke responseComplete() and so on yourself. This method also properly deals with IE-specific headers and UTF-8 filenames. You can find source code here.

Angular.js ng-repeat filter by property having one of multiple values (OR of values)

I found a more generic solution with the most angular-native solution I can think. Basically you can pass your own comparator to the default filterFilter function. Here's plunker as well.

List directory in Go

ioutil.ReadDir is a good find, but if you click and look at the source you see that it calls the method Readdir of os.File. If you are okay with the directory order and don't need the list sorted, then this Readdir method is all you need.

Java ArrayList replace at specific index

Use the set() method: see doc

arraylist.set(index,newvalue);

How to secure phpMyAdmin

You can use the following command :

$ grep "phpmyadmin" $path_to_access.log | grep -Po "^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}" | sort | uniq | xargs -I% sudo iptables -A INPUT -s % -j DROP 

Explanation:

Make sure your IP isn't listed before piping through iptables drop!!

This will first find all lines in $path_to_access.log that have phpmyadmin in them,

then grep out the ip address from the start of the line,

then sort and unique them,

then add a rule to drop them in iptables

Again, just edit in echo % at the end instead of the iptables command to make sure your IP isn't in there. Don't inadvertently ban your access to the server!

Limitations

You may need to change the grep part of the command if you're on mac or any system that doesn't have grep -P. I'm not sure if all systems start with xargs, so that might need to be installed too. It's super useful anyway if you do a lot of bash.

How to extract IP Address in Spring MVC Controller get call?

You can get the IP address statically from the RequestContextHolder as below :

HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes())
        .getRequest();

String ip = request.getRemoteAddr();

Spring Security exclude url patterns in security annotation configurartion

Found the solution in Spring security examples posted in Github.

WebSecurityConfigurerAdapter has a overloaded configure message that takes WebSecurity as argument which accepts ant matchers on requests to be ignored.

@Override
public void configure(WebSecurity web) throws Exception {
    web.ignoring().antMatchers("/authFailure");
}

See Spring Security Samples for more details

VBA array sort function?

I converted the 'fast quick sort' algorithm to VBA, if anyone else wants it.

I have it optimized to run on an array of Int/Longs but it should be simple to convert it to one that works on arbitrary comparable elements.

Private Sub QuickSort(ByRef a() As Long, ByVal l As Long, ByVal r As Long)
    Dim M As Long, i As Long, j As Long, v As Long
    M = 4

    If ((r - l) > M) Then
        i = (r + l) / 2
        If (a(l) > a(i)) Then swap a, l, i '// Tri-Median Methode!'
        If (a(l) > a(r)) Then swap a, l, r
        If (a(i) > a(r)) Then swap a, i, r

        j = r - 1
        swap a, i, j
        i = l
        v = a(j)
        Do
            Do: i = i + 1: Loop While (a(i) < v)
            Do: j = j - 1: Loop While (a(j) > v)
            If (j < i) Then Exit Do
            swap a, i, j
        Loop
        swap a, i, r - 1
        QuickSort a, l, j
        QuickSort a, i + 1, r
    End If
End Sub

Private Sub swap(ByRef a() As Long, ByVal i As Long, ByVal j As Long)
    Dim T As Long
    T = a(i)
    a(i) = a(j)
    a(j) = T
End Sub

Private Sub InsertionSort(ByRef a(), ByVal lo0 As Long, ByVal hi0 As Long)
    Dim i As Long, j As Long, v As Long

    For i = lo0 + 1 To hi0
        v = a(i)
        j = i
        Do While j > lo0
            If Not a(j - 1) > v Then Exit Do
            a(j) = a(j - 1)
            j = j - 1
        Loop
        a(j) = v
    Next i
End Sub

Public Sub sort(ByRef a() As Long)
    QuickSort a, LBound(a), UBound(a)
    InsertionSort a, LBound(a), UBound(a)
End Sub

How to parse JSON data with jQuery / JavaScript?

var jsonP = "person" : [ { "id" : "1", "name" : "test1" },
  { "id" : "2", "name" : "test2" },
  { "id" : "3", "name" : "test3" },
  { "id" : "4", "name" : "test4" },
  { "id" : "5", "name" : "test5" } ];

var cand = document.getElementById("cand");
var json_arr = [];
$.each(jsonP.person,function(key,value){
    json_arr.push(key+' . '+value.name  + '<br>');
    cand.innerHTML = json_arr;
});

<div id="cand">
</div>

Getting all files in directory with ajax

Javascript which runs on the client machine can't access the local disk file system due to security restrictions.

If you want to access the client's disk file system then look into an embedded client application which you serve up from your webpage, like an Applet, Silverlight or something like that. If you like to access the server's disk file system, then look for the solution in the server side corner using a server side programming language like Java, PHP, etc, whatever your webserver is currently using/supporting.

How to duplicate a git repository? (without forking)

See https://help.github.com/articles/duplicating-a-repository

Short version:

In order to make an exact duplicate, you need to perform both a bare-clone and a mirror-push:

mkdir foo; cd foo 
# move to a scratch dir

git clone --bare https://github.com/exampleuser/old-repository.git
# Make a bare clone of the repository

cd old-repository.git
git push --mirror https://github.com/exampleuser/new-repository.git
# Mirror-push to the new repository

cd ..
rm -rf old-repository.git  
# Remove our temporary local repository

NOTE: the above will work fine with any remote git repo, the instructions are not specific to github

The above creates a new remote copy of the repo. Then clone it down to your working machine.

Opening a CHM file produces: "navigation to the webpage was canceled"

In addition to Eric Leschinski's answer, and because this is stackoverflow, a programmatical solution:

Windows uses hidden file forks to mark content as "downloaded". Truncating these unblocks the file. The name of the stream used for CHM's is "Zone.Identifier". One can access streams by appending :streamname when opening the file. (keep backups the first time, in case your RTL messes that up!)

In Delphi it would look like this:

var f : file;
begin
 writeln('unblocking ',s);
 assignfile(f,'some.chm:Zone.Identifier');
 rewrite(f,1);
 truncate(f);
 closefile(f);
end;

I'm told that on non forked filesystems (like FAT32) there are hidden files, but I haven't gotten to the bottom of that yet.

P.s. Delphi's DeleteFile() should also recognize forks.

How to add multiple values to a dictionary key in python?

Make the value a list, e.g.

a["abc"] = [1, 2, "bob"]

UPDATE:

There are a couple of ways to add values to key, and to create a list if one isn't already there. I'll show one such method in little steps.

key = "somekey"
a.setdefault(key, [])
a[key].append(1)

Results:

>>> a
{'somekey': [1]}

Next, try:

key = "somekey"
a.setdefault(key, [])
a[key].append(2)

Results:

>>> a
{'somekey': [1, 2]}

The magic of setdefault is that it initializes the value for that key if that key is not defined, otherwise it does nothing. Now, noting that setdefault returns the key you can combine these into a single line:

a.setdefault("somekey",[]).append("bob")

Results:

>>> a
{'somekey': [1, 2, 'bob']}

You should look at the dict methods, in particular the get() method, and do some experiments to get comfortable with this.

Multiple Order By with LINQ

You can use the ThenBy and ThenByDescending extension methods:

foobarList.OrderBy(x => x.Foo).ThenBy( x => x.Bar)

Random number from a range in a Bash Script

You can get the random number through urandom

head -200 /dev/urandom | cksum

Output:

3310670062 52870

To retrieve the one part of the above number.

head -200 /dev/urandom | cksum | cut -f1 -d " "

Then the output is

3310670062

To meet your requirement,

head -200 /dev/urandom |cksum | cut -f1 -d " " | awk '{print $1%63000+2001}'

When should I use h:outputLink instead of h:commandLink?

The <h:outputLink> renders a fullworthy HTML <a> element with the proper URL in the href attribute which fires a bookmarkable GET request. It cannot directly invoke a managed bean action method.

<h:outputLink value="destination.xhtml">link text</h:outputLink>

The <h:commandLink> renders a HTML <a> element with an onclick script which submits a (hidden) POST form and can invoke a managed bean action method. It's also required to be placed inside a <h:form>.

<h:form>
    <h:commandLink value="link text" action="destination" />
</h:form>

The ?faces-redirect=true parameter on the <h:commandLink>, which triggers a redirect after the POST (as per the Post-Redirect-Get pattern), only improves bookmarkability of the target page when the link is actually clicked (the URL won't be "one behind" anymore), but it doesn't change the href of the <a> element to be a fullworthy URL. It still remains #.

<h:form>
    <h:commandLink value="link text" action="destination?faces-redirect=true" />
</h:form>

Since JSF 2.0, there's also the <h:link> which can take a view ID (a navigation case outcome) instead of an URL. It will generate a HTML <a> element as well with the proper URL in href.

<h:link value="link text" outcome="destination" />

So, if it's for pure and bookmarkable page-to-page navigation like the SO username link, then use <h:outputLink> or <h:link>. That's also better for SEO since bots usually doesn't cipher POST forms nor JS code. Also, UX will be improved as the pages are now bookmarkable and the URL is not "one behind" anymore.

When necessary, you can do the preprocessing job in the constructor or @PostConstruct of a @RequestScoped or @ViewScoped @ManagedBean which is attached to the destination page in question. You can make use of @ManagedProperty or <f:viewParam> to set GET parameters as bean properties.

See also:

When a 'blur' event occurs, how can I find out which element focus went *to*?

Works in Google Chrome v66.x, Mozilla v59.x and Microsoft Edge... Solution with jQuery.

I test in Internet Explorer 9 and not supported.

$("#YourElement").blur(function(e){
     var InputTarget =  $(e.relatedTarget).attr("id"); // GET ID Element
     console.log(InputTarget);
     if(target == "YourId") { // If you want validate or make a action to specfic element
          ... // your code
     }
});

Comment your test in others internet explorer versions.

Multiline input form field using Bootstrap

The answer by Nick Mitchinson is for Bootstrap version 2.

If you are using Bootstrap version 3, then forms have changed a bit. For bootstrap 3, use the following instead:

<div class="form-horizontal">
    <div class="form-group">
        <div class="col-md-6">
            <textarea class="form-control" rows="3" placeholder="What's up?" required></textarea>
        </div>
    </div>
</div>

Where, col-md-6 will target medium sized devices. You can add col-xs-6 etc to target smaller devices.

Two versions of python on linux. how to make 2.7 the default

Add /usr/local/bin to your PATH environment variable, earlier in the list than /usr/bin.

Generally this is done in your shell's rc file, e.g. for bash, you'd put this in .bashrc:

export PATH="/usr/local/bin:$PATH"

This will cause your shell to look first for a python in /usr/local/bin, before it goes with the one in /usr/bin.

(Of course, this means you also need to have /usr/local/bin/python point to python2.7 - if it doesn't already, you'll need to symlink it.)

Traversing text in Insert mode

You can create mappings that work in insert mode. The way to do that is via inoremap. Note the 'i' at the beginning of the command (noremap is useful to avoid key map collisions). The corollary is 'n' for 'normal' mode. You can surmise what vim thinks is 'normal' ;)

HOWEVER, you really want to navigate around in text using 'normal' mode. Vim is super at this kind of thing and all that power is available from normal mode. Vim already provides easy ways to get from normal mode to insert mode (e.g., i, I, a, A, o, O). The trick is to make it easy to get into normal mode. The way to do that is to remap escape to a more convient key. But you need one that won't conflict with your regular typing. I use:

inoremap jj <Esc>

Since jj (that's 2 j's typed one after the other quickly) doesn't seem to appear in my vocabulary. Other's will remap to where it's comfortable.

The other essential change I make is to switch the CAPSLOCK and CONTROL keys on my keyboard (using the host computer's keyboard configuration) since I almost never use CAPSLOCK and it has that big, beautiful button right where I want it. (This is common for Emacs users. The downside is when you find yourself on an 'unfixed' keyboard! Aaarggh!)

Once you remap CAPSLOCK, you can comfortably use the following insert mode remappings:

Keeping in mind that some keys are already mapped in insert mode (backwards-kill-word is C-w (Control-w) by default, you might already have the bindings you want. That said, I prefer C-h so in my .vimrc I have:

inoremap <C-h> <C-w>

BUT, you probably want the same muscle memory spasm in normal mode, so I also map C-h as:

nnoremap <C-h> db

(d)elete (b)ackwards accomplishes the same thing with the same key chord. This kind of quick edit is one that I find useful in practice for typos. But stick to normal mode for moving around in text and anything more than killing the previous word. Once you get into the habit of changing modes (using a remap of course), it will be much more efficient than remapping insert mode.

Is it possible to display inline images from html in an Android TextView?

I used Dave Webb's answer but simplified it a bit. As long as the resource IDs will stay the same during runtime in your use-case, there's not really a need to write your own class implementing Html.ImageGetter and mess around with source-strings.

What I did was using the resource ID as a source-string:

final String img = String.format("<img src=\"%s\"/>", R.drawable.your_image);
final String html = String.format("Image: %s", img);

and use it directly:

Html.fromHtml(html, new Html.ImageGetter() {
  @Override
  public Drawable getDrawable(final String source) {
    Drawable d = null;
    try {
      d = getResources().getDrawable(Integer.parseInt(source));
      d.setBounds(0, 0, d.getIntrinsicWidth(), d.getIntrinsicHeight());
    } catch (Resources.NotFoundException e) {
      Log.e("log_tag", "Image not found. Check the ID.", e);
    } catch (NumberFormatException e) {
      Log.e("log_tag", "Source string not a valid resource ID.", e);
    }

    return d;
  }
}, null);

Intercept and override HTTP requests from WebView

This may helps:

@TargetApi(Build.VERSION_CODES.LOLLIPOP)
@Override
public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceRequest request) {
    String url = request.getUrl().toString();
    WebResourceResponse response = super.shouldInterceptRequest(view, request);
    // load native js
    if (url != null && url.contains(INJECTION_TOKEN/* scheme define */)) {

        response = new WebResourceResponse(
                "text/javascript",
                "utf-8",
                loadJsInputStream(url, JsCache.getJsFilePath(path) /* InputStream */));
    }
    return response;
}

How to change the port number for Asp.Net core app?

3 files have to changed appsettings.json (see the last section - kestrel ), launchsettings.json - applicationurl commented out, and a 2 lines change in Startup.cs

Add below code in appsettings.json file and port to any as you wish.

  },

 "Kestrel": {

   "Endpoints": {

     "Http": {

       "Url": "http://localhost:5003"

     }

   }

 }

 }

Modify Startup.cs with below lines.

using Microsoft.AspNetCore.Server.Kestrel.Core;

services.Configure<KestrelServerOptions>(Configuration.GetSection("Kestrel"));

How to generate a random alpha-numeric string

Surprising, no one here has suggested it, but:

import java.util.UUID

UUID.randomUUID().toString();

Easy.

The benefit of this is UUIDs are nice, long, and guaranteed to be almost impossible to collide.

Wikipedia has a good explanation of it:

" ...only after generating 1 billion UUIDs every second for the next 100 years, the probability of creating just one duplicate would be about 50%."

The first four bits are the version type and two for the variant, so you get 122 bits of random. So if you want to, you can truncate from the end to reduce the size of the UUID. It's not recommended, but you still have loads of randomness, enough for your 500k records easy.

T-SQL: Export to new Excel file

Use PowerShell:

$Server = "TestServer"
$Database = "TestDatabase"
$Query = "select * from TestTable"
$FilePath = "C:\OutputFile.csv"

# This will overwrite the file if it already exists.
Invoke-Sqlcmd -Query $Query -Database $Database -ServerInstance $Server | Export-Csv $FilePath

In my usual cases, all I really need is a CSV file that can be read by Excel. However, if you need an actual Excel file, then tack on some code to convert the CSV file to an Excel file. This answer gives a solution for this, but I've not tested it.

How do I call a Django function on button click?

The following answer could be helpful for the first part of your question:

Django: How can I call a view function from template?

TestNG ERROR Cannot find class in classpath

If your package name is FabFurnishPackage and your class name is registration then the code in xml should be

<classes>
<class name="FabFurnishPackage.registration">
</classes>

[TestNG] [ERROR] Cannot find class in classpath: registration issue is fixed...

Remove "whitespace" between div element

You need this

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">

<-- I absolutely don't know why, but go ahead, and add this code snippet to your CSS -->

*{
    margin:0;
    padding:0;
}

That's it, have fun removing all those white-spaces problems.

Interfaces vs. abstract classes

Another thing to consider is that, since there is no multiple inheritance, if you want a class to be able to implement/inherit from your interface/abstract class, but inherit from another base class, use an interface.

How can I style the border and title bar of a window in WPF?

You need to set

WindowStyle="None", AllowsTransparency="True" and optionally ResizeMode="NoResize"
and then set the Style property of the window to your custom window style, where you design the appearance of the window (title bar, buttons, border) to anything you want and display the window contents in a ContentPresenter.

This seems to be a good article on how you can achieve this, but there are many other articles on the internet.

How can I return to a parent activity correctly?

You declared activity A with the standard launchMode in the Android manifest. According to the documentation, that means the following:

The system always creates a new instance of the activity in the target task and routes the intent to it.

Therefore, the system is forced to recreate activity A (i.e. calling onCreate) even if the task stack is handled correctly.

To fix this problem you need to change the manifest, adding the following attribute to the A activity declaration:

android:launchMode="singleTop"

Note: calling finish() (as suggested as solution before) works only when you are completely sure that the activity B instance you are terminating lives on top of an instance of activity A. In more complex workflows (for instance, launching activity B from a notification) this might not be the case and you have to correctly launch activity A from B.

Declare variable MySQL trigger

All DECLAREs need to be at the top. ie.

delimiter //

CREATE TRIGGER pgl_new_user 
AFTER INSERT ON users FOR EACH ROW
BEGIN
    DECLARE m_user_team_id integer;
    DECLARE m_projects_id integer;
    DECLARE cur CURSOR FOR SELECT project_id FROM user_team_project_relationships WHERE user_team_id = m_user_team_id;

    SET @m_user_team_id := (SELECT id FROM user_teams WHERE name = "pgl_reporters");

    OPEN cur;
        ins_loop: LOOP
            FETCH cur INTO m_projects_id;
            IF done THEN
                LEAVE ins_loop;
            END IF;
            INSERT INTO users_projects (user_id, project_id, created_at, updated_at, project_access) 
            VALUES (NEW.id, m_projects_id, now(), now(), 20);
        END LOOP;
    CLOSE cur;
END//

How to create materialized views in SQL Server?

They're called indexed views in SQL Server - read these white papers for more background:

Basically, all you need to do is:

  • create a regular view
  • create a clustered index on that view

and you're done!

The tricky part is: the view has to satisfy quite a number of constraints and limitations - those are outlined in the white paper. If you do this, that's all there is. The view is being updated automatically, no maintenance needed.

Additional resources:

what is the multicast doing on 224.0.0.251?

If you don't have avahi installed then it's probably cups.

How to show particular image as thumbnail while implementing share on Facebook?

I also had an issue on a site I was working on last week. I implemented a like box and tested the like box. Then I went ahead to add an image to my header (the ob:image meta). Still the correct image did not show up on my facebook notification.

I tried everything, and came to the conclusion that every single implementation of a like button is cached. So let's say you clock the Like button on url A, then you specify an image in the header and you test it by clicking the Luke button again on url A. You won't see the image as the page is cached. The image will show up when you click on the Like button on page B.

To reset the cache, you have to use the lint debugger tool that's mentioned above, and validate all the Urls for those that are cached... That's the only thing that worked for me.

How to get $HOME directory of different user in bash script?

For the sake of an alternative answer for those searching for a lightweight way to just find a user's home dir...

Rather than messing with su hacks, or bothering with the overhead of launching another bash shell just to find the $HOME environment variable...

Lightweight Simple Homedir Query via Bash

There is a command specifically for this: getent

getent passwd someuser | cut -f6 -d:

getent can do a lot more... just see the man page. The passwd nsswitch database will return the user's entry in /etc/passwd format. Just split it on the colon : to parse out the fields.

It should be installed on most Linux systems (or any system that uses GNU Lib C (RHEL: glibc-common, Deb: libc-bin)

text-align: right on <select> or <option>

The following CSS will right-align both the arrow and the options:

_x000D_
_x000D_
select { text-align-last: right; }_x000D_
option { direction: rtl; }
_x000D_
<!-- example usage -->_x000D_
Choose one: <select>_x000D_
  <option>The first option</option>_x000D_
  <option>A second, fairly long option</option>_x000D_
  <option>Last</option>_x000D_
</select>
_x000D_
_x000D_
_x000D_

getDate with Jquery Datepicker

You can format the jquery date with this line:

moment($(elem).datepicker('getDate')).format("YYYY-MM-DD");

http://momentjs.com

Floating divs in Bootstrap layout

From all I have read you cannot do exactly what you want without javascript. If you float left before text

<div style="float:left;">widget</div> here is some CONTENT, etc.

Your content wraps as expected. But your widget is in the top left. If you instead put the float after the content

here is some CONTENT, etc. <div style="float:left;">widget</div>

Then your content will wrap the last line to the right of the widget if the last line of content can fit to the right of the widget, otherwise no wrapping is done. To make borders and backgrounds actually include the floated area in the previous example, most people add:

here is some CONTENT, etc. <div style="float:left;">widget</div><div style="clear:both;"></div>

In your question you are using bootstrap which just adds row-fluid::after { content: ""} which resolves the border/background issue.

Moving your content up will give you the one line wrap : http://jsfiddle.net/jJNPY/34/

  <div class="container-fluid">
  <div class="row-fluid">
    <div class="offset1 span8 pull-right">
    ... Widget 1...
    </div>
    .... a lot of content ....
    <div class="span8" style="margin-left: 0;">
    ... Widget 2...
    </div>


  </div>

</div><!--/.fluid-container-->

How to POST URL in data of a curl request

I don't think it's necessary to use semi-quotes around the variables, try:

curl -XPOST 'http://localhost/Service' -d "path=%2fxyz%2fpqr%2ftest%2f&fileName=1.doc"

%2f is the escape code for a /.

http://www.december.com/html/spec/esccodes.html

Also, do you need to specify a port? ( just checking :) )

Convert Uppercase Letter to Lowercase and First Uppercase in Sentence using CSS

There is no sentence caps option in CSS. The other answers suggesting text-transform: capitalize are incorrect as that option capitalizes each word.

Here's a crude way to accomplish it if you only want the first letter of each element to be uppercase, but it's definitely nowhere near actual sentence caps:

p {
    text-transform: lowercase;
}

p:first-letter {
    text-transform: uppercase;
}
<p>THIS IS AN EXAMPLE SENTENCE.</p>
<p>THIS IS ANOTHER EXAMPLE SENTENCE.
   AND THIS IS ANOTHER, BUT IT WILL BE ENTIRELY LOWERCASE.</p>

CKEditor, Image Upload (filebrowserUploadUrl)

If you don't want to have to buy CKFinder, like I didn't want to buy CKFinder, then I wrote a very reliable uploader for CKEditor 4. It consists of a second form, placed immediately above your textarea form, and utilizes the iframe hack, which, in spite of its name, is seamless and unobtrusive.

After the image is successfully uploaded, it will appear in your CKEditor window, along with whatever content is already there.

editor.php (the form page):

<?php
set_time_limit ( 3600 )
?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Content Editor</title>
<link href="jquery-ui-1.10.2/themes/vader/ui.dialog.css" rel="stylesheet" media="screen" id="dialog_ui" />
<link href="jquery-ui-1.10.2/themes/vader/jquery-ui.css" rel="stylesheet" media="screen" id="dialog_ui" />
<script src="jquery-ui-1.10.2/jquery-1.9.1.js"></script>
<script src="jquery-ui-1.10.2/jquery.form.js"></script>
<script src="jquery-ui-1.10.2/ui/jquery-ui.js"></script>
<script src="ckeditor/ckeditor.js"></script>
<script src="ckeditor/config.js"></script>
<script src="ckeditor/adapters/jquery.js"></script>
<script src="ckeditor/plugin2.js"></script>
<script type="text/javascript">
$(document).ready(function() {
    $('#editor').ckeditor({ height: 400, width:600});
});

function placePic(){

    function ImageExist(url){
       var img = new Image();
       img.src = url;
       return img.height != 0;
    }

var filename = document.forms['uploader']['uploadedfile'].value;
document.forms['uploader']['filename'].value = filename;
var url = 'http://www.mydomain.com/external/images/cms/'+filename;
document.getElementById('uploader').submit();
var string = CKEDITOR.instances.editor.getData();
var t = setInterval(function(){

            var exists = ImageExist(url);
            if(exists === true){
                    if(document.getElementById('loader')){
                        document.getElementById('loader').parentNode.removeChild(document.getElementById('loader'));
                    }
                    CKEDITOR.instances.editor.setData(string + "<img src=\""+url+"\" />");
                    clearInterval(t);
            }
            else{
                if(! document.getElementById("loader")){
                    var loader = document.createElement("div");
                    loader.setAttribute("id","loader");
                    loader.setAttribute("style","position:absolute;margin:-300px auto 0px 240px;width:113px;height:63px;text-align:center;z-index:10;");
                    document.getElementById('formBox').appendChild(loader);

                    var loaderGif = document.createElement("img");
                    loaderGif.setAttribute("id","loaderGif");
                    loaderGif.setAttribute("style","width:113px;height:63px;text-align:center;");
                    loaderGif.src = "external/images/cms/2dumbfish.gif";
                    document.getElementById('loader').appendChild(loaderGif);
                }
            }

            },100);
}

function loadContent(){
if(document.forms['editorform']['site'].value !== "" && document.forms['editorform']['page'].value !== ""){
    var site = document.forms['editorform']['site'].value;
    var page = document.forms['editorform']['page'].value;
    var url = site+"/"+page+".html";
    $.ajax({
        type: "GET",
        url: url,
        dataType: 'html',
        success: function (html) {
            CKEDITOR.instances.editor.setData(html);
        }
    });
}
}
</script>
<style>
button{
  width: 93px;
  height: 28px;
  border:none;
  padding: 0 4px 8px 0;
  font-weight:bold
}
#formBox{
    width:50%;
margin:10px auto 0px auto;
font-family:Tahoma, Geneva, sans-serif;
font-size:12px;
}
#field{
position:absolute;
top:10px;
margin-left:300px;
margin-bottom:20px;
}
#target{
position:absolute;
top:100px;
left:100px;
width:400px;
height:100px;
display:none;
}
.textField{
    padding-left: 1px;
border-style: solid;
border-color: black;
border-width: 1px;
font-family: helvetica, arial, sans serif;
padding-left: 1px;
}
#report{
float:left;
margin-left:20px;
margin-top:10px;
font-family: helvetica, arial, sans serif;
font-size:12px;
color:#900;
}
</style>
</head>

<body>
<?php
if(isset($_GET['r'])){ ?><div id="report">
<?php echo $_GET['r']; ?> is changed.
</div><?php
}
?>
<div id="formBox">
<form id="uploader" name="uploader" action="editaction.php"  method="post" target="target" enctype="multipart/form-data">
<input type="hidden" name="MAX_FILE_SIZE" value="50000000" />
<input type="hidden" name="filename" value="" />
Insert image:&nbsp;<input name="uploadedfile" type="file" class="textField" onchange="placePic();return false;" />&nbsp;&nbsp;
</form>

<form name="editorform" id="editorform" method="post" action="editaction.php" >
<div id="field" >Site:&nbsp;<select name="site"  class="textField" onchange="loadContent();return false;">
    <option value=""></option>
    <option value="scubatortuga">scubatortuga</option>
    <option value="drytortugascharters">drytortugascharters</option>
    <option value="keyscombo">keyscombo</option>
    <option value="keywesttreasurehunters">keywesttreasurehunters</option>
    <option value="spearfishkeywest">spearfishkeywest</option>
</select>
Page:&nbsp;<select name="page" class="textField" onchange="loadContent();return false;">
    <option value=""></option>
    <option value="one">1</option>
    <option value="two">2</option>
    <option value="three">3</option>
    <option value="four">4</option>
</select>
</div><br />
<textarea name="editor" id="editor"></textarea><br />
<input type="submit" name="submit" value="Submit" />
</form>
</div>
<iframe name="target" id="target"></iframe>
</body>
</html>

And here is the action page, editaction.php, which does the actual file upload:

<?php
//editaction.php

foreach($_POST as $k => $v){
    ${"$k"} = $v;
}
//fileuploader.php
if($_FILES){
  $target_path = "external/images/cms/";
  $target_path = $target_path . basename( $_FILES['uploadedfile']['name']); 
  if(! file_exists("$target_path$filename")){
    move_uploaded_file($_FILES['uploadedfile']['tmp_name'], $target_path);
  }
}
else{
    $string = stripslashes($editor);
    $filename = "$site/$page.html";
    $handle = fopen($filename,"w");
    fwrite($handle,$string,strlen($string));
    fclose($handle);
    header("location: editor.php?r=$filename");
}
?>

Save PHP array to MySQL?

Generally, yes, serialize and unserialize are the way to go.

If your data is something simple, though, saving as a comma-delimited string would probably be better for storage space. If you know that your array will just be a list of numbers, for example, then you should use implode/explode. It's the difference between 1,2,3 and a:3:{i:0;i:1;i:1;i:2;i:2;i:3;}.

If not, then serialize and unserialize work for all cases.

Android: adbd cannot run as root in production builds

You have to grant the Superuser right to the shell app (com.anroid.shell). In my case, I use Magisk to root my phone Nexsus 6P (Oreo 8.1). So I can grant Superuser right in the Magisk Manager app, whih is in the left upper option menu.

Enable PHP Apache2

You have two ways to enable it.

First, you can set the absolute path of the php module file in your httpd.conf file like this:

LoadModule php5_module /path/to/mods-available/libphp5.so

Second, you can link the module file to the mods-enabled directory:

ln -s /path/to/mods-available/libphp5.so /path/to/mods-enabled/libphp5.so

Making div content responsive

Not a lot to go on there, but I think what you're looking for is to flip the width and max-width values:

#container2 {
  width: 90%;
  max-width: 960px;
  /* etc, etc... */
}

That'll give you a container that's 90% of the width of the available space, up to a maximum of 960px, but that's dependent on its container being resizable itself. Responsive design is a whole big ball of wax though, so this doesn't even scratch the surface.

"Multiple definition", "first defined here" errors

Maybe you included the .c file in makefile multiple times.

Get TimeZone offset value from TimeZone without TimeZone name

@MrBean - I was in a similar situation where I had to call a 3rd-party web service and pass in the Android device's current timezone offset in the format +/-hh:mm. Here is my solution:

public static String getCurrentTimezoneOffset() {

    TimeZone tz = TimeZone.getDefault();  
    Calendar cal = GregorianCalendar.getInstance(tz);
    int offsetInMillis = tz.getOffset(cal.getTimeInMillis());

    String offset = String.format("%02d:%02d", Math.abs(offsetInMillis / 3600000), Math.abs((offsetInMillis / 60000) % 60));
    offset = (offsetInMillis >= 0 ? "+" : "-") + offset;

    return offset;
} 

How to get HttpRequestMessage data

I suggest that you should not do it like this. Action methods should be designed to be easily unit-tested. In this case, you should not access data directly from the request, because if you do it like this, when you want to unit test this code you have to construct a HttpRequestMessage.

You should do it like this to let MVC do all the model binding for you:

[HttpPost]
public void Confirmation(YOURDTO yourobj)//assume that you define YOURDTO elsewhere
{
        //your logic to process input parameters.

}

In case you do want to access the request. You just access the Request property of the controller (not through parameters). Like this:

[HttpPost]
public void Confirmation()
{
    var content = Request.Content.ReadAsStringAsync().Result;
}

In MVC, the Request property is actually a wrapper around .NET HttpRequest and inherit from a base class. When you need to unit test, you could also mock this object.

Put current changes in a new Git branch

You can simply check out a new branch, and then commit:

git checkout -b my_new_branch
git commit

Checking out the new branch will not discard your changes.

Convert a list to a string in C#

The direct answer to your question is String.Join as others have mentioned.

However, if you need some manipulations, you can use Aggregate:

List<string> employees = new List<string>();
employees.Add("e1");
employees.Add("e2");
employees.Add("e3");

string employeesString = "'" + employees.Aggregate((x, y) => x + "','" + y) + "'";
Console.WriteLine(employeesString);
Console.ReadLine();

jQuery prevent change for select

If you simply want to prevent interaction with the select altogether when my_condition is true, you could always just capture the mousedown event and do your event prevent there:

var my_condition = true;

$("#my_select").mousedown(function(e){
  if(my_condition)
  {
     e.preventDefault();
     alert("Because my_condition is true, you cannot make this change.");
  }
});

This will prevent any change event from ever occurring while my_condition is true.

How to use setprecision in C++

#include <iomanip>
#include <iostream>

int main()
{
    double num1 = 3.12345678;
    std::cout << std::fixed << std::showpoint;
    std::cout << std::setprecision(2);
    std::cout << num1 << std::endl;
    return 0;
}

Sum all values in every column of a data.frame in R

We can use dplyr to select only numeric columns and purr to get sum for all columns. (can be used to get what ever value for all columns, such as mean, min, max, etc. )

library("dplyr")
library("purrr")

people %>%
    select_if(is.numeric) %>%
    map_dbl(sum)

Or another easy way by only using dplyr

library("dplyr")
people %>%
    summarize_if(is.numeric, sum, na.rm=TRUE)

How to write inline if statement for print?

Python does not have a trailing if statement.

There are two kinds of if in Python:

  1. if statement:

    if condition: statement
    if condition:
        block
    
  2. if expression (introduced in Python 2.5)

    expression_if_true if condition else expression_if_false
    

And note, that both print a and b = a are statements. Only the a part is an expression. So if you write

print a if b else 0

it means

print (a if b else 0)

and similarly when you write

x = a if b else 0

it means

x = (a if b else 0)

Now what would it print/assign if there was no else clause? The print/assignment is still there.

And note, that if you don't want it to be there, you can always write the regular if statement on a single line, though it's less readable and there is really no reason to avoid the two-line variant.

Why Git is not allowing me to commit even after configuration?

That’s a typo. You’ve accidently set user.mail with no e. Fix it by setting user.email in the global configuration with

git config --global user.email "[email protected]"

Lodash - difference between .extend() / .assign() and .merge()

Here's how extend/assign works: For each property in source, copy its value as-is to destination. if property values themselves are objects, there is no recursive traversal of their properties. Entire object would be taken from source and set in to destination.

Here's how merge works: For each property in source, check if that property is object itself. If it is then go down recursively and try to map child object properties from source to destination. So essentially we merge object hierarchy from source to destination. While for extend/assign, it's simple one level copy of properties from source to destination.

Here's simple JSBin that would make this crystal clear: http://jsbin.com/uXaqIMa/2/edit?js,console

Here's more elaborate version that includes array in the example as well: http://jsbin.com/uXaqIMa/1/edit?js,console

Is there a standard function to check for null, undefined, or blank variables in JavaScript?

To check Default Value

function typeOfVar (obj) {
      return {}.toString.call(obj).split(' ')[1].slice(0, -1).toLowerCase();
}
function isVariableHaveDefaltVal(variable) {
    if ( typeof(variable) === 'string' ) {  // number, boolean, string, object 
        console.log(' Any data Between single/double Quotes is treated as String ');        
        return (variable.trim().length === 0) ? true : false;
    }else if ( typeof(variable) === 'boolean' ) {
      console.log('boolean value with default value \'false\'');
        return (variable === false) ? true : false;
    }else if ( typeof(variable) === 'undefined' ) {
        console.log('EX: var a; variable is created, but has the default value of undefined.'); 
        return true;
    }else if ( typeof(variable) === 'number' ) { 
        console.log('number : '+variable);
        return (variable === 0 ) ? true : false;
    }else if ( typeof(variable) === 'object' ) {
   //   -----Object-----
        if (typeOfVar(variable) === 'array' && variable.length === 0) {
            console.log('\t Object Array with length = ' + [].length); // Object.keys(variable)
            return true;
        }else if (typeOfVar(variable) === 'string' && variable.length === 0 ) {
            console.log('\t Object String with length = ' + variable.length);
            return true;
        }else if (typeOfVar(variable) === 'boolean' ) {
            console.log('\t Object Boolean = ' + variable);
            return (variable === false) ? true : false;
        }else if (typeOfVar(variable) === 'number' ) {
            console.log('\t Object Number = ' + variable);
            return (variable === 0 ) ? true : false;
        }else if (typeOfVar(variable) === 'regexp' && variable.source.trim().length === 0 ) {
       console.log('\t Object Regular Expression : ');
        return true;
        }else if (variable === null) {
       console.log('\t Object null value');
        return true;
        }
    }
    return false;
}
var str = "A Basket For Every Occasion";
str = str.replace(/\s/g, "-");
//The "g" flag in the regex will cause all spaces to get replaced.

check Result:

isVariableHaveDefaltVal(' '); // string          
isVariableHaveDefaltVal(false); // boolean       
var a;           
isVariableHaveDefaltVal(a);               
isVariableHaveDefaltVal(0); // number             
isVariableHaveDefaltVal(parseInt('')); // NAN isNAN(' '); - true         
isVariableHaveDefaltVal(null);              
isVariableHaveDefaltVal([]);               
isVariableHaveDefaltVal(/ /);              
isVariableHaveDefaltVal(new Object(''));               
isVariableHaveDefaltVal(new Object(false));            
isVariableHaveDefaltVal(new Object(0)); 
typeOfVar( function() {} );

I used @Vix function() to check the object of which type.

using instansof «

var prototypes_or_Literals = function (obj) {
    switch (typeof(obj)) {
        // object prototypes
        case 'object':
            if (obj instanceof Array)
                return '[object Array]';
            else if (obj instanceof Date)
                return '[object Date]';
            else if (obj instanceof RegExp)
                return '[object regexp]';
            else if (obj instanceof String)
                return '[object String]';
            else if (obj instanceof Number)
                return '[object Number]';

            else
                return 'object';
        // object literals
        default:
            return typeof(obj);
    }   
};
output test «
prototypes_or_Literals( '' ) // "string"
prototypes_or_Literals( new String('') ) // "[object String]"
Object.prototype.toString.call("foo bar") //"[object String]"        

Get: TypeError: 'dict_values' object does not support indexing when using python 3.2.3

In Python 3 the dict.values() method returns a dictionary view object, not a list like it does in Python 2. Dictionary views have a length, can be iterated, and support membership testing, but don't support indexing.

To make your code work in both versions, you could use either of these:

{names[i]:value for i,value in enumerate(d.values())}

    or

values = list(d.values())
{name:values[i] for i,name in enumerate(names)}

By far the simplest, fastest way to do the same thing in either version would be:

dict(zip(names, d.values()))

Note however, that all of these methods will give you results that will vary depending on the actual contents of d. To overcome that, you may be able use an OrderedDict instead, which remembers the order that keys were first inserted into it, so you can count on the order of what is returned by the values() method.

How to remove the arrows from input[type="number"] in Opera

I've been using some simple CSS and it seems to remove them and work fine.

_x000D_
_x000D_
input[type=number]::-webkit-inner-spin-button, _x000D_
input[type=number]::-webkit-outer-spin-button { _x000D_
    -webkit-appearance: none;_x000D_
    -moz-appearance: none;_x000D_
    appearance: none;_x000D_
    margin: 0; _x000D_
}
_x000D_
<input type="number" step="0.01"/>
_x000D_
_x000D_
_x000D_

This tutorial from CSS Tricks explains in detail & also shows how to style them

Algorithm to generate all possible permutations of a list?

Basically, for each item from left to right, all the permutations of the remaining items are generated (and each one is added with the current elements). This can be done recursively (or iteratively if you like pain) until the last item is reached at which point there is only one possible order.

So with the list [1,2,3,4] all the permutations that start with 1 are generated, then all the permutations that start with 2, then 3 then 4.

This effectively reduces the problem from one of finding permutations of a list of four items to a list of three items. After reducing to 2 and then 1 item lists, all of them will be found.
Example showing process permutations using 3 coloured balls:
Red, green and blue coloured balls ordered permutations image (from https://en.wikipedia.org/wiki/Permutation#/media/File:Permutations_RGB.svg - https://commons.wikimedia.org/wiki/File:Permutations_RGB.svg)

Angular 1.6.0: "Possibly unhandled rejection" error

I had this same notice appear after making some changes. It turned out to be because I had changed between a single $http request to multiple requests using angularjs $q service.

I hadn't wrapped them in an array. e.g.

$q.all(request1, request2).then(...) 

rather than

$q.all([request1, request2]).then(...)

I hope this might save somebody some time.