When does Java's Thread.sleep throw InterruptedException?

You should generally NOT ignore the exception. Take a look at the following paper:

Don't swallow interrupts

Sometimes throwing InterruptedException is not an option, such as when a task defined by Runnable calls an interruptible method. In this case, you can't rethrow InterruptedException, but you also do not want to do nothing. When a blocking method detects interruption and throws InterruptedException, it clears the interrupted status. If you catch InterruptedException but cannot rethrow it, you should preserve evidence that the interruption occurred so that code higher up on the call stack can learn of the interruption and respond to it if it wants to. This task is accomplished by calling interrupt() to "reinterrupt" the current thread, as shown in Listing 3. At the very least, whenever you catch InterruptedException and don't rethrow it, reinterrupt the current thread before returning.

public class TaskRunner implements Runnable {
    private BlockingQueue<Task> queue;

    public TaskRunner(BlockingQueue<Task> queue) { 
        this.queue = queue; 
    }

    public void run() { 
        try {
             while (true) {
                 Task task = queue.take(10, TimeUnit.SECONDS);
                 task.execute();
             }
         }
         catch (InterruptedException e) { 
             // Restore the interrupted status
             Thread.currentThread().interrupt();
         }
    }
}

• From Don't swallow interrupts

---

See the entire paper here:

http://www.ibm.com/developerworks/java/library/j-jtp05236/index.html?ca=drs-

Lambda expression to convert array/List of String to array/List of Integers

EDIT: As pointed out in the comments, this is a much simpler version: Arrays.stream(stringArray).mapToInt(Integer::parseInt).toArray() This way we can skip the whole conversion to and from a list.

---

I found another one line solution, but it's still pretty slow (takes about 100 times longer than a for cycle - tested on an array of 6000 0's)

String[] stringArray = ...
int[] out= Arrays.asList(stringArray).stream().map(Integer::parseInt).mapToInt(i->i).toArray();

What this does:

1. Arrays.asList() converts the array to a List
2. .stream converts it to a Stream (needed to perform a map)
3. .map(Integer::parseInt) converts all the elements in the stream to Integers
4. .mapToInt(i->i) converts all the Integers to ints (you don't have to do this if you only want Integers)
5. .toArray() converts the Stream back to an array

Handlebars.js Else If

Handlebars supports {{else if}} blocks as of 3.0.0.

Handlebars v3.0.0 or greater:

{{#if FriendStatus.IsFriend}}
  <div class="ui-state-default ui-corner-all" title=".ui-icon-mail-closed"><span class="ui-icon ui-icon-mail-closed"></span></div>
{{else if FriendStatus.FriendRequested}}
  <div class="ui-state-default ui-corner-all" title=".ui-icon-check"><span class="ui-icon ui-icon-check"></span></div>
{{else}}
  <div class="ui-state-default ui-corner-all" title=".ui-icon-plusthick"><span class="ui-icon ui-icon-plusthick"></span></div>
{{/if}}

Prior to Handlebars v3.0.0, however, you will have to either define a helper that handles the branching logic or nest if statements manually:

{{#if FriendStatus.IsFriend}}
  <div class="ui-state-default ui-corner-all" title=".ui-icon-mail-closed"><span class="ui-icon ui-icon-mail-closed"></span></div>
{{else}}
  {{#if FriendStatus.FriendRequested}}
    <div class="ui-state-default ui-corner-all" title=".ui-icon-check"><span class="ui-icon ui-icon-check"></span></div>
  {{else}}
    <div class="ui-state-default ui-corner-all" title=".ui-icon-plusthick"><span class="ui-icon ui-icon-plusthick"></span></div>
  {{/if}}
{{/if}}

Git push: "fatal 'origin' does not appear to be a git repository - fatal Could not read from remote repository."

This is the way I updated the master branch

This kind of error occurs commonly after deleting the initial code on your project

So, go ahead, first of all, verify the actual remote version, then remove the origin add the comment, and copy the repo URL into the project files.

$ git remote -v
$ git remote rm origin
$ git commit -m "your commit"
$ git remote add origin https://github.com/user/repo.git
$ git push -f origin master

How to append multiple items in one line in Python

You could also:

newlist += mylist[i:i+22]

How to check if array element exists or not in javascript?

(typeof files[1] === undefined)?
            this.props.upload({file: files}):
            this.props.postMultipleUpload({file: files widgetIndex: 0, id})

Check if the second item in the array is undefined using the typeof and checking for undefined

Where to place and how to read configuration resource files in servlet based application?

It just needs to be in the classpath (aka make sure it ends up under /WEB-INF/classes in the .war as part of the build).

Exporting results of a Mysql query to excel?

The typical way to achieve this is to export to CSV and then load the CSV into Excel.
You can using any MySQL command line tool to do this by including the INTO OUTFILE clause on your SELECT statement:

SELECT ... FROM ... WHERE ... 
INTO OUTFILE 'file.csv'
FIELDS TERMINATED BY ','

See this link for detailed options.

Alternatively, you can use mysqldump to store dump into a separated value format using the --tab option, see this link.

mysqldump -u<user> -p<password> -h<host> --where=jtaskResult=2429 --tab=<file.csv> <database> TaskResult

Hint: If you don't specify an absoulte path but use something like INTO OUTFILE 'output.csv' or INTO OUTFILE './output.csv', it will store the output file to the directory specified by show variables like 'datadir';.

How can I listen to the form submit event in javascript?

With jQuery:

$('form').submit(function () {
    // Validate here

    if (pass)
        return true;
    else
        return false;
});

Use underscore inside Angular controllers

You can also take a look at this module for angular

https://github.com/floydsoft/angular-underscore

How link to any local file with markdown syntax?

Thank you drifty0pine!

The first solution, it´s works!

[a relative link](../../some/dir/filename.md)
[Link to file in another dir on same drive](/another/dir/filename.md)
[Link to file in another dir on a different drive](/D:/dir/filename.md)

but I had need put more ../ until the folder where was my file, like this:

[FileToOpen](../../../../folderW/folderX/folderY/folderZ/FileToOpen.txt)

Boolean operators ( &&, -a, ||, -o ) in Bash

-a and -o are the older and/or operators for the test command. && and || are and/or operators for the shell. So (assuming an old shell) in your first case,

[ "$1" = 'yes' ] && [ -r $2.txt ]

The shell is evaluating the and condition. In your second case,

[ "$1" = 'yes' -a $2 -lt 3 ]

The test command (or builtin test) is evaluating the and condition.

Of course in all modern or semi-modern shells, the test command is built in to the shell, so there really isn't any or much difference. In modern shells, the if statement can be written:

[[ $1 == yes && -r $2.txt ]]

Which is more similar to modern programming languages and thus is more readable.

What does 'low in coupling and high in cohesion' mean

Long story short, low coupling as I understood it meant components can be swapped out without affecting the proper functioning of a system. Basicaly modulize your system into functioning components that can be updated individually without breaking the system

how to read certain columns from Excel using Pandas - Python

"usecols" should help, use range of columns (as per excel worksheet, A,B...etc.) below are the examples

1. Selected Columns

df = pd.read_excel(file_location,sheet_name='Sheet1', usecols="A,C,F")

2. Range of Columns and selected column

df = pd.read_excel(file_location,sheet_name='Sheet1', usecols="A:F,H")

3. Multiple Ranges

df = pd.read_excel(file_location,sheet_name='Sheet1', usecols="A:F,H,J:N")

4. Range of columns

df = pd.read_excel(file_location,sheet_name='Sheet1', usecols="A:N")

Certificate is trusted by PC but not by Android

could be that you're missing the certificate on your device.

try looking at this answer: How to install trusted CA certificate on Android device? to see how to install the CA on your own device.

Inserting a Python datetime.datetime object into MySQL

when iserting into t-sql

this fails:

select CONVERT(datetime,'2019-09-13 09:04:35.823312',21)

this works:

select CONVERT(datetime,'2019-09-13 09:04:35.823',21)

easy way:

regexp = re.compile(r'\.(\d{6})')
def to_splunk_iso(dt):
    """Converts the datetime object to Splunk isoformat string."""
    # 6-digits string.
    microseconds = regexp.search(dt).group(1)
    return regexp.sub('.%d' % round(float(microseconds) / 1000), dt)

Sort & uniq in Linux shell

sort -u will be slightly faster, because it does not need to pipe the output between two commands

also see my question on the topic: calling uniq and sort in different orders in shell

How do I extend a class with c# extension methods?

Unfortunately, you can't do that. I believe it would be useful, though. It is more natural to type:

DateTime.Tomorrow

than:

DateTimeUtil.Tomorrow

With a Util class, you have to check for the existence of a static method in two different classes, instead of one.

LINQ Joining in C# with multiple conditions

As far as I know you can only join this way:

var query = from obj_i in set1
join obj_j in set2 on 
    new { 
      JoinProperty1 = obj_i.SomeField1,
      JoinProperty2 = obj_i.SomeField2,
      JoinProperty3 = obj_i.SomeField3,
      JoinProperty4 = obj_i.SomeField4
    } 
    equals 
    new { 
      JoinProperty1 = obj_j.SomeOtherField1,
      JoinProperty2 = obj_j.SomeOtherField2,
      JoinProperty3 = obj_j.SomeOtherField3,
      JoinProperty4 = obj_j.SomeOtherField4
    }

The main requirements are: Property names, types and order in the anonymous objects you're joining on must match.

You CAN'T use ANDs, ORs, etc. in joins. Just object1 equals object2.

More advanced stuff in this LinqPad example:

class c1 
    {
    public int someIntField;
    public string someStringField;
    }
    
class c2 
    {
    public Int64 someInt64Property {get;set;}
    private object someField;
    public string someStringFunction(){return someField.ToString();}
    }
    
void Main()
{
    var set1 = new List<c1>();
    var set2 = new List<c2>();
    
    var query = from obj_i in set1
    join obj_j in set2 on 
        new { 
                JoinProperty1 = (Int64) obj_i.someIntField,
                JoinProperty2 = obj_i.someStringField
            } 
        equals 
        new { 
                JoinProperty1 = obj_j.someInt64Property,
                JoinProperty2 = obj_j.someStringFunction()
            }
    select new {obj1 = obj_i, obj2 = obj_j};
}

Addressing names and property order is straightforward, addressing types can be achieved via casting/converting/parsing/calling methods etc. This might not always work with LINQ to EF or SQL or NHibernate, most method calls definitely won't work and will fail at run-time, so YMMV (Your Mileage May Vary). This is because they are copied to public read-only properties in the anonymous objects, so as long as your expression produces values of correct type the join property - you should be fine.

How do I add 24 hours to a unix timestamp in php?

As you have said if you want to add 24 hours to the timestamp for right now then simply you can do:

 <?php echo strtotime('+1 day'); ?>

Above code will add 1 day or 24 hours to your current timestamp.

in place of +1 day you can take whatever you want, As php manual says strtotime can Parse about any English textual datetime description into a Unix timestamp.

examples from the manual are as below:

<?php
     echo strtotime("now"), "\n";
     echo strtotime("10 September 2000"), "\n";
     echo strtotime("+1 day"), "\n";
     echo strtotime("+1 week"), "\n";
     echo strtotime("+1 week 2 days 4 hours 2 seconds"), "\n";
     echo strtotime("next Thursday"), "\n";
     echo strtotime("last Monday"), "\n";
?>

vba pass a group of cells as range to function

As written, your function accepts only two ranges as arguments.

To allow for a variable number of ranges to be used in the function, you need to declare a ParamArray variant array in your argument list. Then, you can process each of the ranges in the array in turn.

For example,

Function myAdd(Arg1 As Range, ParamArray Args2() As Variant) As Double
    Dim elem As Variant
    Dim i As Long
    For Each elem In Arg1
        myAdd = myAdd + elem.Value
    Next elem
    For i = LBound(Args2) To UBound(Args2)
        For Each elem In Args2(i)
            myAdd = myAdd + elem.Value
        Next elem
    Next i
End Function

This function could then be used in the worksheet to add multiple ranges.

For your function, there is the question of which of the ranges (or cells) that can passed to the function are 'Sessions' and which are 'Customers'.

The easiest case to deal with would be if you decided that the first range is Sessions and any subsequent ranges are Customers.

Function calculateIt(Sessions As Range, ParamArray Customers() As Variant) As Double
    'This function accepts a single Sessions range and one or more Customers
    'ranges
    Dim i As Long
    Dim sessElem As Variant
    Dim custElem As Variant
    For Each sessElem In Sessions
        'do something with sessElem.Value, the value of each
        'cell in the single range Sessions
        Debug.Print "sessElem: " & sessElem.Value
    Next sessElem
    'loop through each of the one or more ranges in Customers()
    For i = LBound(Customers) To UBound(Customers)
        'loop through the cells in the range Customers(i)
        For Each custElem In Customers(i)
            'do something with custElem.Value, the value of
            'each cell in the range Customers(i)
            Debug.Print "custElem: " & custElem.Value
         Next custElem
    Next i
End Function

If you want to include any number of Sessions ranges and any number of Customers range, then you will have to include an argument that will tell the function so that it can separate the Sessions ranges from the Customers range.

This argument could be set up as the first, numeric, argument to the function that would identify how many of the following arguments are Sessions ranges, with the remaining arguments implicitly being Customers ranges. The function's signature would then be:

Function calculateIt(numOfSessionRanges, ParamAray Args() As Variant)

Or it could be a "guard" argument that separates the Sessions ranges from the Customers ranges. Then, your code would have to test each argument to see if it was the guard. The function would look like:

Function calculateIt(ParamArray Args() As Variant)

Perhaps with a call something like:

calculateIt(sessRange1,sessRange2,...,"|",custRange1,custRange2,...)

The program logic might then be along the lines of:

Function calculateIt(ParamArray Args() As Variant) As Double
   ...
   'loop through Args
   IsSessionArg = True
   For i = lbound(Args) to UBound(Args)
       'only need to check for the type of the argument
       If TypeName(Args(i)) = "String" Then
          IsSessionArg = False
       ElseIf IsSessionArg Then
          'process Args(i) as Session range
       Else
          'process Args(i) as Customer range
       End if
   Next i
   calculateIt = <somevalue>
End Function

Can you get the column names from a SqlDataReader?

For me, I would write an extension method like this:

public static string[] GetFieldNames(this SqlDataReader reader)
{
     return Enumerable.Range(0, reader.FieldCount).Select(x => reader.GetName(x)).ToArray();
}

In Perl, what is the difference between a .pm (Perl module) and .pl (Perl script) file?

At the very core, the file extension you use makes no difference as to how perl interprets those files.

However, putting modules in .pm files following a certain directory structure that follows the package name provides a convenience. So, if you have a module Example::Plot::FourD and you put it in a directory Example/Plot/FourD.pm in a path in your @INC, then use and require will do the right thing when given the package name as in use Example::Plot::FourD.

The file must return true as the last statement to indicate successful execution of any initialization code, so it's customary to end such a file with 1; unless you're sure it'll return true otherwise. But it's better just to put the 1;, in case you add more statements.

If EXPR is a bareword, the require assumes a ".pm" extension and replaces "::" with "/" in the filename for you, to make it easy to load standard modules. This form of loading of modules does not risk altering your namespace.

All use does is to figure out the filename from the package name provided, require it in a BEGIN block and invoke import on the package. There is nothing preventing you from not using use but taking those steps manually.

For example, below I put the Example::Plot::FourD package in a file called t.pl, loaded it in a script in file s.pl.

C:\Temp> cat t.pl
package Example::Plot::FourD;

use strict; use warnings;

sub new { bless {} => shift }

sub something { print "something\n" }

"Example::Plot::FourD"

C:\Temp> cat s.pl
#!/usr/bin/perl
use strict; use warnings;

BEGIN {
    require 't.pl';
}

my $p = Example::Plot::FourD->new;
$p->something;


C:\Temp> s
something

This example shows that module files do not have to end in 1, any true value will do.

Laravel 5 - artisan seed [ReflectionException] Class SongsTableSeeder does not exist

I solved it by doing this:

1. Copy the file content.
2. Remove file.
3. Run command: php artisan make:seeder .
4. Copy the file content back in this file.

This happened because I made a change in the filename. I don't know why it didn't work after the change.

how to re-format datetime string in php?

You can use date_parse_from_format() function ...

Check this link..you will get clear idea

How can I make Java print quotes, like "Hello"?

char ch='"';

System.out.println(ch + "String" + ch);

Or

System.out.println('"' + "ASHISH" + '"');

Declaring a xsl variable and assigning value to it

No, unlike in a lot of other languages, XSLT variables cannot change their values after they are created. You can however, avoid extraneous code with a technique like this:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="xml" indent="yes" omit-xml-declaration="yes"/>

  <xsl:variable name="mapping">
    <item key="1" v1="A" v2="B" />
    <item key="2" v1="X" v2="Y" />
  </xsl:variable>
  <xsl:variable name="mappingNode"
                select="document('')//xsl:variable[@name = 'mapping']" />

  <xsl:template match="....">
    <xsl:variable name="testVariable" select="'1'" />

    <xsl:variable name="values" select="$mappingNode/item[@key = $testVariable]" />

    <xsl:variable name="variable1" select="$values/@v1" />
    <xsl:variable name="variable2" select="$values/@v2" />
  </xsl:template>
</xsl:stylesheet>

In fact, once you've got the values variable, you may not even need separate variable1 and variable2 variables. You could just use $values/@v1 and $values/@v2 instead.

Insert a line at specific line number with sed or awk

OS X / macOS / FreeBSD sed

The -i flag works differently on macOS sed than in GNU sed.

Here's the way to use it on macOS / OS X:

sed -i '' '8i\
8 This is Line 8' FILE

See man 1 sed for more info.

Ruby value of a hash key?

It seems that your question is maybe a bit ambiguous.

If “values” in the first sentence means any generic value (i.e. object, since everything in Ruby can be viewed as an object), then one of the other answers probably tells you what you need to know (i.e. use Hash#[] (e.g. hash[some_key]) to find the value associated with a key).

If, however, “values” in first sentence is taken to mean the value part of the “key, value pairs” (as are stored in hashes), then your question seems like it might be about working in the other direction (key for a given value).

You can find a key that leads to a certain value with Hash#key.

ruby-1.9.2-head :001 > hash = { :a => '1', :b => :two, :c => 3, 'bee' => :two }
 => {:a=>"1", :b=>:two, :c=>3, "bee"=>:two} 
ruby-1.9.2-head :002 > a_value = :two
 => :two 
ruby-1.9.2-head :003 > hash.key(a_value)
 => :b 

If you are using a Ruby earlier than 1.9, you can use Hash#index.

When there are multiple keys with the desired value, the method will only return one of them. If you want all the keys with a given value, you may have to iterate a bit:

ruby-1.9.2-head :004 > hash[:b] == hash['bee']
 => true 
ruby-1.9.2-head :005 > keys = hash.inject([]) do # all keys with value a_value
ruby-1.9.2-head :006 >       |l,kv| kv[1] == a_value ? l << kv[0] : l
ruby-1.9.2-head :007?>   end
 => [:b, "bee"] 

Once you have a key (the keys) that lead to the value, you can compare them and act on them with if/unless/case expressions, custom methods that take blocks, et cetera. Just how you compare them depends on the kind of objects you are using for keys (people often use strings and symbols, but Ruby hashes can use any kind of object as keys (as long as they are not modified while they serve as keys)).

Is there a job scheduler library for node.js?

node-crontab allows you to edit system cron jobs from node.js. Using this library will allow you to run programs even after your main process termintates. Disclaimer: I'm the developer.

How do I check OS with a preprocessor directive?

Based on nadeausoftware and Lambda Fairy's answer.

#include <stdio.h>

/**
 * Determination a platform of an operation system
 * Fully supported supported only GNU GCC/G++, partially on Clang/LLVM
 */

#if defined(_WIN32)
    #define PLATFORM_NAME "windows" // Windows
#elif defined(_WIN64)
    #define PLATFORM_NAME "windows" // Windows
#elif defined(__CYGWIN__) && !defined(_WIN32)
    #define PLATFORM_NAME "windows" // Windows (Cygwin POSIX under Microsoft Window)
#elif defined(__ANDROID__)
    #define PLATFORM_NAME "android" // Android (implies Linux, so it must come first)
#elif defined(__linux__)
    #define PLATFORM_NAME "linux" // Debian, Ubuntu, Gentoo, Fedora, openSUSE, RedHat, Centos and other
#elif defined(__unix__) || !defined(__APPLE__) && defined(__MACH__)
    #include <sys/param.h>
    #if defined(BSD)
        #define PLATFORM_NAME "bsd" // FreeBSD, NetBSD, OpenBSD, DragonFly BSD
    #endif
#elif defined(__hpux)
    #define PLATFORM_NAME "hp-ux" // HP-UX
#elif defined(_AIX)
    #define PLATFORM_NAME "aix" // IBM AIX
#elif defined(__APPLE__) && defined(__MACH__) // Apple OSX and iOS (Darwin)
    #include <TargetConditionals.h>
    #if TARGET_IPHONE_SIMULATOR == 1
        #define PLATFORM_NAME "ios" // Apple iOS
    #elif TARGET_OS_IPHONE == 1
        #define PLATFORM_NAME "ios" // Apple iOS
    #elif TARGET_OS_MAC == 1
        #define PLATFORM_NAME "osx" // Apple OSX
    #endif
#elif defined(__sun) && defined(__SVR4)
    #define PLATFORM_NAME "solaris" // Oracle Solaris, Open Indiana
#else
    #define PLATFORM_NAME NULL
#endif

// Return a name of platform, if determined, otherwise - an empty string
const char *get_platform_name() {
    return (PLATFORM_NAME == NULL) ? "" : PLATFORM_NAME;
}

int main(int argc, char *argv[]) {
    puts(get_platform_name());
    return 0;
}

Tested with GCC and clang on:

• Debian 8
• Windows (MinGW)
• Windows (Cygwin)

How to Replace Multiple Characters in SQL?

I would seriously consider making a CLR UDF instead and using regular expressions (both the string and the pattern can be passed in as parameters) to do a complete search and replace for a range of characters. It should easily outperform this SQL UDF.

How to get the current branch name in Git?

Well simple enough, I got it in a one liner (bash)

git branch | sed -n '/\* /s///p'

(credit: Limited Atonement)

And while I am there, the one liner to get the remote tracking branch (if any)

git rev-parse --symbolic-full-name --abbrev-ref @{u}

Proper way to restrict text input values (e.g. only numbers)

<input type="number" onkeypress="return event.charCode >= 48 && event.charCode <= 57" ondragstart="return false;" ondrop="return false;"> 

Input filed only accept numbers, But it's temporary fix only.

How to get the clicked link's href with jquery?

$(".testClick").click(function () {
         var value = $(this).attr("href");
         alert(value );     
}); 

When you use $(".className") you are getting the set of all elements that have that class. Then when you call attr it simply returns the value of the first item in the collection.

Create folder with batch but only if it doesn't already exist

This should work for you:

IF NOT EXIST "\path\to\your\folder" md \path\to\your\folder

However, there is another method, but it may not be 100% useful:

md \path\to\your\folder >NUL 2>NUL

This one creates the folder, but does not show the error output if folder exists. I highly recommend that you use the first one. The second one is if you have problems with the other.

Bash scripting missing ']'

If you created your script on windows and want to run it on linux machine, and you're sure there is no mistake in your code, install dos2unix on linux machine and run dos2unix yourscript.sh. Then, run the script.

Jquery UI tooltip does not support html content

From http://bugs.jqueryui.com/ticket/9019

Putting HTML within the title attribute is not valid HTML and we are now escaping it to prevent XSS vulnerabilities (see #8861).

If you need HTML in your tooltips use the content option - http://api.jqueryui.com/tooltip/#option-content.

Try to use javascript to set html tooltips, see below

$( ".selector" ).tooltip({
   content: "Here is your HTML"
});

Frame Buster Buster ... buster code needed

What about calling the buster repeatedly as well? This'll create a race condition, but one may hope that the buster comes out on top:

(function() {
    if(top !== self) {
        top.location.href = self.location.href;
        setTimeout(arguments.callee, 0);
    }
})();

Failure [INSTALL_FAILED_INVALID_APK]

taskAffinity name must have at least one '.' separator

How to check if spark dataframe is empty?

I had the same question, and I tested 3 main solution :

1. (df != null) && (df.count > 0)
2. df.head(1).isEmpty() as @hulin003 suggest
3. df.rdd.isEmpty() as @Justin Pihony suggest

and of course the 3 works, however in term of perfermance, here is what I found, when executing the these methods on the same DF in my machine, in terme of execution time :

1. it takes ~9366ms
2. it takes ~5607ms
3. it takes ~1921ms
   

therefore I think that the best solution is df.rdd.isEmpty() as @Justin Pihony suggest

Error in installation a R package

There could be a few things happening here. Start by first figuring out your library location:

Sys.getenv("R_LIBS_USER")

or

.libPaths()

We already know yours from the info you gave: C:\Program Files\R\R-3.0.1\library

I believe you have a file in there called: 00LOCK. From ?install.packages:

Note that it is possible for the package installation to fail so badly that the lock directory is not removed: this inhibits any further installs to the library directory (or for --pkglock, of the package) until the lock directory is removed manually.

You need to delete that file. If you had the pacman package installed you could have simply used p_unlock() and the 00LOCK file is removed. You can't install pacman now until the 00LOCK file is removed.

To install pacman use:

install.packages("pacman")

There may be a second issue. This is where you somehow corrupted MASS. This can occur, in my experience, if you try to update a package while it is in use in another R session. I'm sure there's other ways to cause this as well. To solve this problem try:

1. Close out of all R sessions (use task manager to ensure you're truly R session free) Ctrl + Alt + Delete
2. Go to your library location Sys.getenv("R_LIBS_USER"). In your case this is: C:\Program Files\R\R-3.0.1\library
3. Manually delete the MASS package
4. Fire up a vanilla session of R
5. Install MASS via install.packages("MASS")

If any of this works please let me know what worked.

How to avoid Python/Pandas creating an index in a saved csv?

As others have stated, if you don't want to save the index column in the first place, you can use df.to_csv('processed.csv', index=False)

However, since the data you will usually use, have some sort of index themselves, let's say a 'timestamp' column, I would keep the index and load the data using it.

So, to save the indexed data, first set their index and then save the DataFrame:

df.set_index('timestamp')
df.to_csv('processed.csv')

Afterwards, you can either read the data with the index:

pd.read_csv('processed.csv', index_col='timestamp')

or read the data, and then set the index:

pd.read_csv('filename.csv')
pd.set_index('column_name')

Identifying Exception Type in a handler Catch Block

you can add some extra information to your exception in your class and then when you catch the exception you can control your custom information to identify your exception

this.Data["mykey"]="keyvalue"; //you can add any type of data if you want 

and then you can get your value

string mystr = (string) err.Data["mykey"];

like that for more information: http://msdn.microsoft.com/en-us/library/system.exception.data.aspx

JFrame in full screen Java

Easiest fix ever:

for ( Window w : Window.getWindows() ) {
    GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().setFullScreenWindow( w );
}

How to calculate a mod b in Python?

A = [3, 1, 2, 4]
for a in A:
    print(a % 2)

output:

1
1
0
0

Using python PIL to turn a RGB image into a pure black and white image

from PIL import Image 
image_file = Image.open("convert_image.png") # open colour image
image_file = image_file.convert('1') # convert image to black and white
image_file.save('result.png')

yields

one line if statement in php

You can use Ternary operator logic Ternary operator logic is the process of using "(condition)? (true return value) : (false return value)" statements to shorten your if/else structures. i.e

/* most basic usage */
$var = 5;
$var_is_greater_than_two = ($var > 2 ? true : false); // returns true

How can I get the count of milliseconds since midnight for the current?

Calendar.getInstance().get(Calendar.MILLISECOND);

convert string date to java.sql.Date

This works for me without throwing an exception:

package com.sandbox;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class Sandbox {

    public static void main(String[] args) throws ParseException {
        SimpleDateFormat format = new SimpleDateFormat("yyyyMMdd");
        Date parsed = format.parse("20110210");
        java.sql.Date sql = new java.sql.Date(parsed.getTime());
    }


}

Show "Open File" Dialog

Addition to what Albert has already said:

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

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

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

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

re.sub erroring with "Expected string or bytes-like object"

As you stated in the comments, some of the values appeared to be floats, not strings. You will need to change it to strings before passing it to re.sub. The simplest way is to change location to str(location) when using re.sub. It wouldn't hurt to do it anyways even if it's already a str.

letters_only = re.sub("[^a-zA-Z]",  # Search for all non-letters
                          " ",          # Replace all non-letters with spaces
                          str(location))

Using onBackPressed() in Android Fragments

requireActivity().onBackPressedDispatcher.addCallback(viewLifecycleOwner, object : OnBackPressedCallback(true) {
            override fun handleOnBackPressed() {
                Log.w("a","")
            }
        })

How to merge two PDF files into one in Java?

A quick Google search returned this bug: "Bad file descriptor while saving a document w. imported PDFs".

It looks like you need to keep the PDFs to be merged open, until after you have saved and closed the combined PDF.

How do I escape ampersands in XML so they are rendered as entities in HTML?

When your XML contains &, this will result in the text &.

When you use that in HTML, that will be rendered as &.

Count number of objects in list

length(x)

Get or set the length of vectors (including lists) and factors, and of any other R object for which a method has been defined.

lengths(x)

Get the length of each element of a list or atomic vector (is.atomic) as an integer or numeric vector.

Microsoft SQL Server 2005 service fails to start

While that error message is on the screen (before the rollback begins) go to Control Panel -> Administrative Tools -> Services and see if the service is actually installed. Also check what account it is using to run as. If it's not using Local System, then double and triple check that the account it's using has rights to the program directory where MS SQL installed to.

Render HTML to PDF in Django site

Try the solution from Reportlab.

Download it and install it as usual with python setup.py install

You will also need to install the following modules: xhtml2pdf, html5lib, pypdf with easy_install.

Here is an usage example:

First define this function:

import cStringIO as StringIO
from xhtml2pdf import pisa
from django.template.loader import get_template
from django.template import Context
from django.http import HttpResponse
from cgi import escape


def render_to_pdf(template_src, context_dict):
    template = get_template(template_src)
    context = Context(context_dict)
    html  = template.render(context)
    result = StringIO.StringIO()

    pdf = pisa.pisaDocument(StringIO.StringIO(html.encode("ISO-8859-1")), result)
    if not pdf.err:
        return HttpResponse(result.getvalue(), content_type='application/pdf')
    return HttpResponse('We had some errors<pre>%s</pre>' % escape(html))

Then you can use it like this:

def myview(request):
    #Retrieve data or whatever you need
    return render_to_pdf(
            'mytemplate.html',
            {
                'pagesize':'A4',
                'mylist': results,
            }
        )

The template:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
    <head>
        <title>My Title</title>
        <style type="text/css">
            @page {
                size: {{ pagesize }};
                margin: 1cm;
                @frame footer {
                    -pdf-frame-content: footerContent;
                    bottom: 0cm;
                    margin-left: 9cm;
                    margin-right: 9cm;
                    height: 1cm;
                }
            }
        </style>
    </head>
    <body>
        <div>
            {% for item in mylist %}
                RENDER MY CONTENT
            {% endfor %}
        </div>
        <div id="footerContent">
            {%block page_foot%}
                Page <pdf:pagenumber>
            {%endblock%}
        </div>
    </body>
</html>

Hope it helps.

How to add Tomcat Server in eclipse

There are different eclipse plugins available to manage Tomcat server and create war file.

For example you can use tomcatPlugin. It permits to start/stop and build the war simply. You can read this tutorial.

What is the best way to test for an empty string with jquery-out-of-the-box?

To checks for all 'empties' like null, undefined, '', ' ', {}, [].

var isEmpty = function(data) {
    if(typeof(data) === 'object'){
        if(JSON.stringify(data) === '{}' || JSON.stringify(data) === '[]'){
            return true;
        }else if(!data){
            return true;
        }
        return false;
    }else if(typeof(data) === 'string'){
        if(!data.trim()){
            return true;
        }
        return false;
    }else if(typeof(data) === 'undefined'){
        return true;
    }else{
        return false;
    }
}

Use cases and results.

console.log(isEmpty()); // true
console.log(isEmpty(null)); // true
console.log(isEmpty('')); // true
console.log(isEmpty('  ')); // true
console.log(isEmpty(undefined)); // true
console.log(isEmpty({})); // true
console.log(isEmpty([])); // true
console.log(isEmpty(0)); // false
console.log(isEmpty('Hey')); // false

type object 'datetime.datetime' has no attribute 'datetime'

Datetime is a module that allows for handling of dates, times and datetimes (all of which are datatypes). This means that datetime is both a top-level module as well as being a type within that module. This is confusing.

Your error is probably based on the confusing naming of the module, and what either you or a module you're using has already imported.

>>> import datetime
>>> datetime
<module 'datetime' from '/usr/lib/python2.6/lib-dynload/datetime.so'>
>>> datetime.datetime(2001,5,1)
datetime.datetime(2001, 5, 1, 0, 0)

But, if you import datetime.datetime:

>>> from datetime import datetime
>>> datetime
<type 'datetime.datetime'>
>>> datetime.datetime(2001,5,1) # You shouldn't expect this to work 
                                # as you imported the type, not the module
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: type object 'datetime.datetime' has no attribute 'datetime'
>>> datetime(2001,5,1)
datetime.datetime(2001, 5, 1, 0, 0)

I suspect you or one of the modules you're using has imported like this: from datetime import datetime.

Proper way to exit iPhone application?

After some tests, I can say the following:

• using the private interface : [UIApplication sharedApplication] will cause the app looking like it crashed, BUT it will call - (void)applicationWillTerminate:(UIApplication *)application before doing so;
• using exit(0); will also terminate the application, but it will look "normal" (the springboard's icons appears like expected, with the zoom out effect), BUT it won't call the - (void)applicationWillTerminate:(UIApplication *)application delegate method.

My advice:

1. Manually call the - (void)applicationWillTerminate:(UIApplication *)application on the delegate.
2. Call exit(0);.

How do I get the HTML code of a web page in PHP?

Simple way: Use file_get_contents():

$page = file_get_contents('http://stackoverflow.com/questions/ask');

Please note that allow_url_fopen must be true in you php.ini to be able to use URL-aware fopen wrappers.

More advanced way: If you cannot change your PHP configuration, allow_url_fopen is false by default and if ext/curl is installed, use the cURL library to connect to the desired page.

How do I define and use an ENUM in Objective-C?

This is how Apple does it for classes like NSString:

In the header file:

enum {
    PlayerStateOff,
    PlayerStatePlaying,
    PlayerStatePaused
};

typedef NSInteger PlayerState;

Refer to Coding Guidelines at http://developer.apple.com/

Best practice to look up Java Enum

Apache Commons Lang 3 contais the class EnumUtils. If you aren't using Apache Commons in your projects, you're doing it wrong. You are reinventing the wheel!

There's a dozen of cool methods that we could use without throws an Exception. For example:

Gets the enum for the class, returning null if not found.

This method differs from Enum.valueOf in that it does not throw an exceptionfor an invalid enum name and performs case insensitive matching of the name.

EnumUtils.getEnumIgnoreCase(SeasonEnum.class, season);

How to get a Static property with Reflection

Ok so the key for me was to use the .FlattenHierarchy BindingFlag. I don't really know why I just added it on a hunch and it started working. So the final solution that allows me to get Public Instance or Static Properties is:

obj.GetType.GetProperty(propName, Reflection.BindingFlags.Public _
  Or Reflection.BindingFlags.Static Or Reflection.BindingFlags.Instance Or _
  Reflection.BindingFlags.FlattenHierarchy)

Mysql password expired. Can't connect

MySQL password expiry

Resetting the password will only solve the problem temporarily. From MySQL 5.7.4 to 5.7.10 (to encourage better security - see MySQL: Password Expiration Policy) the default default_password_lifetime variable value is 360 (1 year-ish). For those versions, if you make no changes to this variable (or to individual user accounts) all passwords expire after 360 days.

So from a script you might get the message: "Your password has expired. To log in you must change it using a client that supports expired passwords."

To stop automatic password expiry, log in as root (mysql -u root -p), then, for clients that automatically connect to the server (e.g. scripts.) change password expiration settings:

ALTER USER 'script'@'localhost' PASSWORD EXPIRE NEVER;

OR you can disable automatic password expiration for all users:

SET GLOBAL default_password_lifetime = 0;

As pointed out by Mertaydin in the comments, to make this permanent add the following line to a my.cnf file MySQL reads on startup, under the [mysqld] group of settings. The location of my.cnf depends on your setup (e.g. Windows, or Homebrew on OS X, or an installer), and whether you want this per-user on Unix or global:

[mysqld] default_password_lifetime = 0 (There may be other settings here too...)

See the MySQL docs on configuration files.

How To Remove Outline Border From Input Button

Removing nessorry accessible event not a good idea in up to standard web developments. either way if you looking for a solution removing just the outline doesn't solve the problem. you also have to remove the blue color shadow. for specific scenarios use a separate class name to isolate the this special style to your button.

.btn.focus, .btn:focus {
    outline: 0;
    box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, .25);
}

Better do this

.remove-border.focus, .remove-border:focus {
        outline: 0;
        box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, .25);
 }

R: how to label the x-axis of a boxplot

If you read the help file for ?boxplot, you'll see there is a names= parameter.

     boxplot(apple, banana, watermelon, names=c("apple","banana","watermelon"))

Conda environments not showing up in Jupyter Notebook

The nb_conda_kernels package is the best way to use jupyter with conda. With minimal dependencies and configuration, it allows you to use other conda environments from a jupyter notebook running in a different environment. Quoting its documentation:

Installation

This package is designed to be managed solely using conda. It should be installed in the environment from which you run Jupyter Notebook or JupyterLab. This might be your base conda environment, but it need not be. For instance, if the environment notebook_env contains the notebook package, then you would run

conda install -n notebook_env nb_conda_kernels

Any other environments you wish to access in your notebooks must have an appropriate kernel package installed. For instance, to access a Python environment, it must have the ipykernel package; e.g.

conda install -n python_env ipykernel

To utilize an R environment, it must have the r-irkernel package; e.g.

conda install -n r_env r-irkernel

For other languages, their corresponding kernels must be installed.

Then all you need to do is start the jupyter notebook server:

conda activate notebook_env  # only needed if you are not using the base environment for the server
# conda install jupyter # in case you have not installed it already
jupyter

---

Despite the plethora of answers and @merv's efforts to improve them, it still hard to find a good one. I made this one CW, so please vote it to the top or improve it!

How to output loop.counter in python jinja template?

The counter variable inside the loop is called loop.index in jinja2.

>>> from jinja2 import Template

>>> s = "{% for element in elements %}{{loop.index}} {% endfor %}"
>>> Template(s).render(elements=["a", "b", "c", "d"])
1 2 3 4

See http://jinja.pocoo.org/docs/templates/ for more.

Java double.MAX_VALUE?

Resurrecting the dead here, but just in case someone stumbles against this like myself. I know where to get the maximum value of a double, the (more) interesting part was to how did they get to that number.

double has 64 bits. The first one is reserved for the sign.

Next 11 represent the exponent (that is 1023 biased). It's just another way to represent the positive/negative values. If there are 11 bits then the max value is 1023.

Then there are 52 bits that hold the mantissa.

This is easily computed like this for example:

public static void main(String[] args) {

    String test = Strings.repeat("1", 52);

    double first = 0.5;
    double result = 0.0;
    for (char c : test.toCharArray()) {
        result += first;
        first = first / 2;
    }

    System.out.println(result); // close approximation of 1
    System.out.println(Math.pow(2, 1023) * (1 + result));
    System.out.println(Double.MAX_VALUE);

} 

You can also prove this in reverse order :

    String max = "0" + Long.toBinaryString(Double.doubleToLongBits(Double.MAX_VALUE));

    String sign = max.substring(0, 1);
    String exponent = max.substring(1, 12); // 11111111110
    String mantissa = max.substring(12, 64);

    System.out.println(sign); // 0 - positive
    System.out.println(exponent); // 2046 - 1023 = 1023
    System.out.println(mantissa); // 0.99999...8

Clear the value of bootstrap-datepicker

I was having similar trouble and the following worked for me:

$('#datepicker').val('').datepicker('update');

Both method calls were needed, otherwise it didn't clear.

Python: OSError: [Errno 2] No such file or directory: ''

I had this error because I was providing a string of arguments to subprocess.call instead of an array of arguments. To prevent this, use shlex.split:

import shlex, subprocess
command_line = "ls -a"
args = shlex.split(command_line)
p = subprocess.Popen(args)

CSS: 100% width or height while keeping aspect ratio?

Its best to use auto on the dimension that should respect the aspect ratio. If you do not set the other property to auto, most browsers nowadays will assume that you want to respect the aspect ration, but not all of them (IE10 on windows phone 8 does not, for example)

width: 100%;
height: auto;

How do I create a transparent Activity on Android?

Declare your activity in the manifest like this:

 <activity   
     android:name=".yourActivity"    
     android:theme="@android:style/Theme.Translucent.NoTitleBar.Fullscreen"/>

And add a transparent background to your layout.

Check if string begins with something?

Have a look at JavaScript substring() method.

Difference between $(window).load() and $(document).ready() functions

<html>
<head>
    <script src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
    <script>
    $( document ).ready(function() {
        alert( "document loaded" );
    });

    $( window ).load(function() {
        alert( "window loaded" );
    });
    </script>
</head>
<body>
    <iframe src="http://stackoverflow.com"></iframe>
</body>
</html>

window.load will be triggered after all the iframe content is loaded

"CSV file does not exist" for a filename with embedded quotes

Sometimes we ignore a little bit issue which is not a Python or IDE fault its logical error We assumed a file .csv which is not a .csv file its a Excell Worksheet file have a look

---

---

When you try to open that file using Import compiler will through the error have a look

To Resolve the issue

open your Target file into Microsoft Excell and save that file in .csv format it is important to note that Encoding is important because it will help you to open the file when you try to open it with

with open('YourTargetFile.csv','r',encoding='UTF-8') as file:

So you are set to go now Try to open your file as this

import csv
with open('plain.csv','r',encoding='UTF-8') as file:
load = csv.reader(file)
for line in load:
    print(line)

Here is the Output

How do you send an HTTP Get Web Request in Python?

You can use urllib2

import urllib2
content = urllib2.urlopen(some_url).read()
print content

Also you can use httplib

import httplib
conn = httplib.HTTPConnection("www.python.org")
conn.request("HEAD","/index.html")
res = conn.getresponse()
print res.status, res.reason
# Result:
200 OK

or the requests library

import requests
r = requests.get('https://api.github.com/user', auth=('user', 'pass'))
r.status_code
# Result:
200

How to convert an enum type variable to a string?

Another late to the party, using the preprocessor:

 1  #define MY_ENUM_LIST \
 2      DEFINE_ENUM_ELEMENT(First) \
 3      DEFINE_ENUM_ELEMENT(Second) \
 4      DEFINE_ENUM_ELEMENT(Third) \
 5  
 6  //--------------------------------------
 7  #define DEFINE_ENUM_ELEMENT(name) , name
 8  enum MyEnum {
 9      Zeroth = 0
10      MY_ENUM_LIST
11  };
12  #undef DEFINE_ENUM_ELEMENT
13 
14  #define DEFINE_ENUM_ELEMENT(name) , #name
15  const char* MyEnumToString[] = {
16      "Zeroth"
17      MY_ENUM_LIST
18  };
19  #undef DEFINE_ENUM_ELEMENT
20
21  #define DEFINE_ENUM_ELEMENT(name) else if (strcmp(s, #name)==0) return name;
22  enum MyEnum StringToMyEnum(const char* s){
23      if (strcmp(s, "Zeroth")==0) return Zeroth;
24      MY_ENUM_LIST
25      return NULL;
26  }
27  #undef DEFINE_ENUM_ELEMENT

(I just put in line numbers so it's easier to talk about.) Lines 1-4 are what you edit to define the elements of the enum. (I have called it a "list macro", because it's a macro that makes a list of things. @Lundin informs me these are a well-known technique called X-macros.)

Line 7 defines the inner macro so as to fill in the actual enum declaration in lines 8-11. Line 12 undefines the inner macro (just to silence the compiler warning).

Line 14 defines the inner macro so as to create a string version of the enum element name. Then lines 15-18 generate an array that can convert an enum value to the corresponding string.

Lines 21-27 generate a function that converts a string to the enum value, or returns NULL if the string doesn't match any.

This is a little cumbersome in the way it handles the 0th element. I've actually worked around that in the past.

I admit this technique bothers people who don't want to think the preprocessor itself can be programmed to write code for you. I think it strongly illustrates the difference between readability and maintainability. The code is difficult to read, but if the enum has a few hundred elements, you can add, remove, or rearrange elements and still be sure the generated code has no errors.

How to chain scope queries with OR instead of AND?

Update for Rails4

requires no 3rd party gems

a = Person.where(name: "John") # or any scope 
b = Person.where(lastname: "Smith") # or any scope 
Person.where([a, b].map{|s| s.arel.constraints.reduce(:and) }.reduce(:or))\
  .tap {|sc| sc.bind_values = [a, b].map(&:bind_values) }

Old answer

requires no 3rd party gems

Person.where(
    Person.where(:name => "John").where(:lastname => "Smith")
      .where_values.reduce(:or)
)

Render partial view with dynamic model in Razor view engine and ASP.NET MVC 3

Instead of casting the model in the RenderPartial call, and since you're using razor, you can modify the first line in your view from

@model dynamic

to

@model YourNamespace.YourModelType

This has the advantage of working on every @Html.Partial call you have in the view, and also gives you intellisense for the properties.

Stored procedure or function expects parameter which is not supplied

In my case I received this exception even when all parameter values were correctly supplied but the type of command was not specified :

cmd.CommandType = System.Data.CommandType.StoredProcedure;

This is obviously not the case in the question above, but exception description is not very clear in this case, so I decided to specify that.

Java for loop syntax: "for (T obj : objects)"

It's called a for-each or enhanced for statement. See the JLS §14.14.2.

It's syntactic sugar provided by the compiler for iterating over Iterables and arrays. The following are equivalent ways to iterate over a list:

List<Foo> foos = ...;
for (Foo foo : foos)
{
    foo.bar();
}

// equivalent to:
List<Foo> foos = ...;
for (Iterator<Foo> iter = foos.iterator(); iter.hasNext();)
{
    Foo foo = iter.next();
    foo.bar();
}

and these are two equivalent ways to iterate over an array:

int[] nums = ...;
for (int num : nums)
{
    System.out.println(num);
}

// equivalent to:
int[] nums = ...;
for (int i=0; i<nums.length; i++)
{
    int num = nums[i];
    System.out.println(num);
}

Further reading

• How is Java's for loop code generated by the compiler
• The For-Each Loop

Find what 2 numbers add to something and multiply to something

That's basically a set of 2 simultaneous equations:

x*y = a
X+y = b

(using the mathematical convention of x and y for the variables to solve and a and b for arbitrary constants).

But the solution involves a quadratic equation (because of the x*y), so depending on the actual values of a and b, there may not be a solution, or there may be multiple solutions.

Regular cast vs. static_cast vs. dynamic_cast

C-style casts conflate const_cast, static_cast, and reinterpret_cast.

I wish C++ didn't have C-style casts. C++ casts stand out properly (as they should; casts are normally indicative of doing something bad) and properly distinguish between the different kinds of conversion that casts perform. They also permit similar-looking functions to be written, e.g. boost::lexical_cast, which is quite nice from a consistency perspective.

Detecting a redirect in ajax request?

Welcome to the future!

Right now we have a "responseURL" property from xhr object. YAY!

See How to get response url in XMLHttpRequest?

However, jQuery (at least 1.7.1) doesn't give an access to XMLHttpRequest object directly. You can use something like this:

var xhr;
var _orgAjax = jQuery.ajaxSettings.xhr;
jQuery.ajaxSettings.xhr = function () {
  xhr = _orgAjax();
  return xhr;
};

jQuery.ajax('http://test.com', {
  success: function(responseText) {
    console.log('responseURL:', xhr.responseURL, 'responseText:', responseText);
  }
});

It's not a clean solution and i suppose jQuery team will make something for responseURL in the future releases.

TIP: just compare original URL with responseUrl. If it's equal then no redirect was given. If it's "undefined" then responseUrl is probably not supported. However as Nick Garvey said, AJAX request never has the opportunity to NOT follow the redirect but you may resolve a number of tasks by using responseUrl property.

Redirect to an external URL from controller action in Spring MVC

You can do this in pretty concise way using ResponseEntity like this:

  @GetMapping
  ResponseEntity<Void> redirect() {
    return ResponseEntity.status(HttpStatus.FOUND)
        .location(URI.create("http://www.yahoo.com"))
        .build();
  }

Which version of MVC am I using?

Select the System.Web.Mvc assembly in the "References" folder in the solution explorer. Bring up the properties window (F4) and check the Version

Google Maps API 3 - Custom marker color for default (dot) marker

Well the closest thing I've been able to get with the StyledMarker is this.

The bullet in the middle isn't quite a big as the default one though. The StyledMarker class simply builds this url and asks the google api to create the marker.

From the class use example use "%E2%80%A2" as your text, as in:

var styleMaker2 = new StyledMarker({styleIcon:new StyledIcon(StyledIconTypes.MARKER,{text:"%E2%80%A2"},styleIconClass),position:new google.maps.LatLng(37.263477473067, -121.880502070713),map:map});

You will need to modifiy StyledMarker.js to comment out the lines:

  if (text_) {
    text_ = text_.substr(0,2);
  }

as this will trim the text string to 2 characters.

Alternatively you could create custom marker images based on the default one with the colors you desire and override the default marker with code such as this:

marker = new google.maps.Marker({
  map:map,
  position: latlng,
  icon: new google.maps.MarkerImage(
    'http://www.gettyicons.com/free-icons/108/gis-gps/png/24/needle_left_yellow_2_24.png',
    new google.maps.Size(24, 24),
    new google.maps.Point(0, 0),
    new google.maps.Point(0, 24)
  )
});

How to get milliseconds from LocalDateTime in Java 8

What I do so I don't specify a time zone is,

System.out.println("ldt " + LocalDateTime.now().atZone(ZoneId.systemDefault()).toInstant().toEpochMilli());
System.out.println("ctm " + System.currentTimeMillis());

gives

ldt 1424812121078 
ctm 1424812121281

As you can see the numbers are the same except for a small execution time.

Just in case you don't like System.currentTimeMillis, use Instant.now().toEpochMilli()

How to change position of Toast in Android?

//A custom toast class where you can show custom or default toast as desired)

public class ToastMessage {
            private Context context;
            private static ToastMessage instance;

            /**
             * @param context
             */
            private ToastMessage(Context context) {
                this.context = context;
            }

            /**
             * @param context
             * @return
             */
            public synchronized static ToastMessage getInstance(Context context) {
                if (instance == null) {
                    instance = new ToastMessage(context);
                }
                return instance;
            }

            /**
             * @param message
             */
            public void showLongMessage(String message) {
                Toast.makeText(context, message, Toast.LENGTH_SHORT).show();
            }

            /**
             * @param message
             */
            public void showSmallMessage(String message) {
                Toast.makeText(context, message, Toast.LENGTH_LONG).show();
            }

            /**
             * The Toast displayed via this method will display it for short period of time
             *
             * @param message
             */
            public void showLongCustomToast(String message) {
                LayoutInflater inflater = ((Activity) context).getLayoutInflater();
                View layout = inflater.inflate(R.layout.layout_custom_toast, (ViewGroup) ((Activity) context).findViewById(R.id.ll_toast));
                TextView msgTv = (TextView) layout.findViewById(R.id.tv_msg);
                msgTv.setText(message);
                Toast toast = new Toast(context);
                toast.setGravity(Gravity.FILL_HORIZONTAL | Gravity.BOTTOM, 0, 0);
                toast.setDuration(Toast.LENGTH_LONG);
                toast.setView(layout);
                toast.show();


            }

            /**
             * The toast displayed by this class will display it for long period of time
             *
             * @param message
             */
            public void showSmallCustomToast(String message) {

                LayoutInflater inflater = ((Activity) context).getLayoutInflater();
                View layout = inflater.inflate(R.layout.layout_custom_toast, (ViewGroup) ((Activity) context).findViewById(R.id.ll_toast));
                TextView msgTv = (TextView) layout.findViewById(R.id.tv_msg);
                msgTv.setText(message);
                Toast toast = new Toast(context);
                toast.setGravity(Gravity.FILL_HORIZONTAL | Gravity.BOTTOM, 0, 0);
                toast.setDuration(Toast.LENGTH_SHORT);
                toast.setView(layout);
                toast.show();
            }

        }

How to load external scripts dynamically in Angular?

I have done this code snippet with the new renderer api

 constructor(private renderer: Renderer2){}

 addJsToElement(src: string): HTMLScriptElement {
    const script = document.createElement('script');
    script.type = 'text/javascript';
    script.src = src;
    this.renderer.appendChild(document.body, script);
    return script;
  }

And then call it like this

this.addJsToElement('https://widgets.skyscanner.net/widget-server/js/loader.js').onload = () => {
        console.log('SkyScanner Tag loaded');
} 

StackBlitz

The name 'InitializeComponent' does not exist in the current context

After some action the namespace of the .cs file and the one in .xaml file may be different (in xaml look for the x:Class="namespace.yourType").

Fix them to be the same.

How to calculate difference between two dates in oracle 11g SQL

Oracle support Mathematical Subtract - operator on Data datatype. You may directly put in select clause following statement:

to_char (s.last_upd – s.created, ‘999999D99')

Check the EXAMPLE for more visibility.

In case you need the output in termes of hours, then the below might help;

Select to_number(substr(numtodsinterval([END_TIME]-[START_TIME]),’day’,2,9))*24 +
to_number(substr(numtodsinterval([END_TIME]-[START_TIME],’day’),12,2))
||':’||to_number(substr(numtodsinterval([END_TIME]-[START_TIME],’day’),15,2)) 
from [TABLE_NAME];

How to save a dictionary to a file?

For a dictionary of strings such as the one you're dealing with, it could be done using only Python's built-in text processing capabilities.

(Note this wouldn't work if the values are something else.)

with open('members.txt') as file:
    mdict={}
    for line in file:
        a, b, c, d = line.strip().split(':')
        mdict[a] = b + ':' + c + ':' + d

a = input('ID: ')
if a not in mdict:
    print('ID {} not found'.format(a))
else:
    b, c, d = mdict[a].split(':')
    d = input('phone: ')
    mdict[a] = b + ':' + c + ':' + d  # update entry
    with open('members.txt', 'w') as file:  # rewrite file
        for id, values in mdict.items():
            file.write(':'.join([id] + values.split(':')) + '\n')

what's the differences between r and rb in fopen

• "r" is the same as "rt" for Translated mode
• "rb" is non-translated mode.

This makes a difference on Windows, at least. See that link for details.

Is there any ASCII character for <br>?

You may be looking for the special HTML character, 
 .

You can use this to get a line break, and it can be inserted immediately following the last character in the current line. One place this is especially useful is if you want to include multiple lines in a list within a title or alt label.

Difference between left join and right join in SQL Server

You seem to be asking, "If I can rewrite a RIGHT OUTER JOIN using LEFT OUTER JOIN syntax then why have a RIGHT OUTER JOIN syntax at all?" I think the answer to this question is, because the designers of the language didn't want to place such a restriction on users (and I think they would have been criticized if they did), which would force users to change the order of tables in the FROM clause in some circumstances when merely changing the join type.

Trying to Validate URL Using JavaScript

This is what worked for me:

function validateURL(value) {
    return /^(https?|ftp):\/\/(((([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:)*@)?(((\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])\.(\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])\.(\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])\.(\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5]))|((([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.)+(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.?)(:\d*)?)(\/((([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:|@)+(\/(([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:|@)*)*)?)?(\?((([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:|@)|[\uE000-\uF8FF]|\/|\?)*)?(\#((([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:|@)|\/|\?)*)?$/i.test(value);
    }

from there is is just a matter of calling the function to get a true or false back:

validateURL(urltovalidate);

How to create a sleep/delay in nodejs that is Blocking?

blocking the main thread is not a good style for node because in most cases more then one person is using it. You should use settimeout/setinterval in combination with callbacks.

How can I save multiple documents concurrently in Mongoose/Node.js?

Mongoose does now support passing multiple document structures to Model.create. To quote their API example, it supports being passed either an array or a varargs list of objects with a callback at the end:

Candy.create({ type: 'jelly bean' }, { type: 'snickers' }, function (err, jellybean, snickers) {
    if (err) // ...
});

Or

var array = [{ type: 'jelly bean' }, { type: 'snickers' }];
Candy.create(array, function (err, jellybean, snickers) {
    if (err) // ...
});

Edit: As many have noted, this does not perform a true bulk insert - it simply hides the complexity of calling save multiple times yourself. There are answers and comments below explaining how to use the actual Mongo driver to achieve a bulk insert in the interest of performance.

What is the difference between active and passive FTP?

Active Mode—The client issues a PORT command to the server signaling that it will “actively” provide an IP and port number to open the Data Connection back to the client.

Passive Mode—The client issues a PASV command to indicate that it will wait “passively” for the server to supply an IP and port number, after which the client will create a Data Connection to the server.

There are lots of good answers above, but this blog post includes some helpful graphics and gives a pretty solid explanation: https://titanftp.com/2018/08/23/what-is-the-difference-between-active-and-passive-ftp/

How can I convert an image into Base64 string using JavaScript?

Here is the way you can do with Javascript Promise.

const getBase64 = (file) => new Promise(function (resolve, reject) {
    let reader = new FileReader();
    reader.readAsDataURL(file);
    reader.onload = () => resolve(reader.result)
    reader.onerror = (error) => reject('Error: ', error);
})

Now, use it in event handler.

const _changeImg = (e) => {
        const file = e.target.files[0];
        let encoded;
        getBase64(file)
          .then((result) => {
            encoded = result;
           })
          .catch(e => console.log(e))
    }

Python convert decimal to hex

In order to put the number in the correct order i modified your code to have a variable (s) for the output. This allows you to put the characters in the correct order.

s=""
def ChangeHex(n):
    if (n < 0):
        print(0)
    elif (n<=1):
        print(n)
    else:
        x =(n%16)
        if (x < 10):
            s=str(x)+s, 
        if (x == 10):
            s="A"+s,
        if (x == 11):
            s="B"+s,
        if (x == 12):
            s="C"+s,
        if (x == 13):
            s="D"+s,
        if (x == 14):
            s="E"+s,
        if (x == 15):
            s="F"+s,
        ChangeHex( n / 16 )        

NOTE: This was done in python 3.7.4 so it may not work for you.

Javascript return number of days,hours,minutes,seconds between two dates

Here is a code example. I used simple calculations instead of using precalculations like 1 day is 86400 seconds. So you can follow the logic with ease.

// Calculate time between two dates:
var date1 = new Date('1110-01-01 11:10');
var date2 = new Date();

console.log('difference in ms', date1 - date2);

// Use Math.abs() so the order of the dates can be ignored and you won't
// end up with negative numbers when date1 is before date2.
console.log('difference in ms abs', Math.abs(date1 - date2));
console.log('difference in seconds', Math.abs(date1 - date2) / 1000);

var diffInSeconds = Math.abs(date1 - date2) / 1000;
var days = Math.floor(diffInSeconds / 60 / 60 / 24);
var hours = Math.floor(diffInSeconds / 60 / 60 % 24);
var minutes = Math.floor(diffInSeconds / 60 % 60);
var seconds = Math.floor(diffInSeconds % 60);
var milliseconds = Math.round((diffInSeconds - Math.floor(diffInSeconds)) * 1000);

console.log('days', days);
console.log('hours', ('0' + hours).slice(-2));
console.log('minutes', ('0' + minutes).slice(-2));
console.log('seconds', ('0' + seconds).slice(-2));
console.log('milliseconds', ('00' + milliseconds).slice(-3));

How to rebuild docker container in docker-compose.yml?

docker-compose stop nginx # stop if running
docker-compose rm -f nginx # remove without confirmation
docker-compose build nginx # build
docker-compose up -d nginx # create and start in background

Removing container with rm is essential. Without removing, Docker will start old container.

Touch move getting stuck Ignored attempt to cancel a touchmove

Calling preventDefault on touchmove while you're actively scrolling is not working in Chrome. To prevent performance issues, you cannot interrupt a scroll.

Try to call preventDefault() from touchstart and everything should be ok.

How do you use variables in a simple PostgreSQL script?

Postgresql does not have bare variables, you could use a temporary table. variables are only available in code blocks or as a user-interface feature.

If you need a bare variable you could use a temporary table:

CREATE TEMP TABLE list AS VALUES ('foobar');

SELECT dbo.PubLists.*
FROM   dbo.PubLists,list
WHERE  Name = list.column1;

Tomcat view catalina.out log file

I have used this command to check the logs and 10000 is used to show the number of lines

sudo tail  -10000f catalina.out

Java 8 method references: provide a Supplier capable of supplying a parameterized result

optionalUsers.orElseThrow(() -> new UsernameNotFoundException("Username not found"));

what is the difference between json and xml

The difference between XML and JSON is that XML is a meta-language/markup language and JSON is a lightweight data-interchange. That is, XML syntax is designed specifically to have no inherent semantics. Particular element names don't mean anything until a particular processing application processes them in a particular way. By contrast, JSON syntax has specific semantics built in stuff between {} is an object, stuff between [] is an array, etc.

A JSON parser, therefore, knows exactly what every JSON document means. An XML parser only knows how to separate markup from data. To deal with the meaning of an XML document, you have to write additional code.

To illustrate the point, let me borrow Guffa's example:

{   "persons": [
  {
    "name": "Ford Prefect",
    "gender": "male"
 },
 {
   "name": "Arthur Dent",
   "gender": "male"
  },
  {
    "name": "Tricia McMillan",
    "gender": "female"
  }   ] }

The XML equivalent he gives is not really the same thing since while the JSON example is semantically complete, the XML would require to be interpreted in a particular way to have the same effect. In effect, the JSON is an example uses an established markup language of which the semantics are already known, whereas the XML example creates a brand new markup language without any predefined semantics.

A better XML equivalent would be to define a (fictitious) XJSON language with the same semantics as JSON, but using XML syntax. It might look something like this:

<xjson>   
  <object>
    <name>persons</name>
    <value>
      <array>
         <object>
            <value>Ford Prefect</value>
            <gender>male</gender>
         </object>
         <object>
            <value>Arthur Dent</value>
            <gender>male</gender>
         </object>
         <object>
            <value>Tricia McMillan</value>
            <gender>female</gender>
         </object>
      </array>
    </value>   
  </object> 
 </xjson>

Once you wrote an XJSON processor, it could do exactly what JSON processor does, for all the types of data that JSON can represent, and you could translate data losslessly between JSON and XJSON.

So, to complain that XML does not have the same semantics as JSON is to miss the point. XML syntax is semantics-free by design. The point is to provide an underlying syntax that can be used to create markup languages with any semantics you want. This makes XML great for making up ad-hoc data and document formats, because you don't have to build parsers for them, you just have to write a processor for them.

But the downside of XML is that the syntax is verbose. For any given markup language you want to create, you can come up with a much more succinct syntax that expresses the particular semantics of your particular language. Thus JSON syntax is much more compact than my hypothetical XJSON above.

If follows that for really widely used data formats, the extra time required to create a unique syntax and write a parser for that syntax is offset by the greater succinctness and more intuitive syntax of the custom markup language. It also follows that it often makes more sense to use JSON, with its established semantics, than to make up lots of XML markup languages for which you then need to implement semantics.

It also follows that it makes sense to prototype certain types of languages and protocols in XML, but, once the language or protocol comes into common use, to think about creating a more compact and expressive custom syntax.

It is interesting, as a side note, that SGML recognized this and provided a mechanism for specifying reduced markup for an SGML document. Thus you could actually write an SGML DTD for JSON syntax that would allow a JSON document to be read by an SGML parser. XML removed this capability, which means that, today, if you want a more compact syntax for a specific markup language, you have to leave XML behind, as JSON does.

How to declare and add items to an array in Python?

Arrays (called list in python) use the [] notation. {} is for dict (also called hash tables, associated arrays, etc in other languages) so you won't have 'append' for a dict.

If you actually want an array (list), use:

array = []
array.append(valueToBeInserted)

Why boolean in Java takes only true or false? Why not 1 or 0 also?

On a related note: the java compiler uses int to represent boolean since JVM has a limited support for the boolean type.See Section 3.3.4 The boolean type.

In JVM, the integer zero represents false, and any non-zero integer represents true (Source : Inside Java Virtual Machine by Bill Venners)

Broadcast receiver for checking internet connection in android app

Answer to your first question: Your broadcast receiver is being called two times because

You have added two <intent-filter>

1. Change in network connection :
   <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />

2. Change in WiFi state:
   <action android:name="android.net.wifi.WIFI_STATE_CHANGED" />

Just use one:
<action android:name="android.net.conn.CONNECTIVITY_CHANGE" />.

It will respond to only one action instead of two. See here for more information.

Answer to your second question (you want receiver to call only one time if internet connection available):

Your code is perfect; you notify only when internet is available.

UPDATE

You can use this method to check your connectivity if you want just to check whether mobile is connected with the internet or not.

public boolean isOnline(Context context) {

    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo netInfo = cm.getActiveNetworkInfo();
    //should check null because in airplane mode it will be null
    return (netInfo != null && netInfo.isConnected());
}

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

Used this for show text

var data = $('#id-selected-input').select2('data'); 
data.forEach(function (item) { 
    alert(item.text); 
})

PHP-FPM doesn't write to error log

I'd like to add another tip to the existing answers because they did not solve my problem.

Watch out for the following nginx directive in your php location block:

fastcgi_intercept_errors on;

Removing this line has brought an end to many hours of struggling and pulling hair.

It could be hidden in some included conf directory like /etc/nginx/default.d/php.conf in my fedora.

How can I pull from remote Git repository and override the changes in my local repository?

As an addendum, if you want to reapply your changes on top of the remote, you can also try:

git pull --rebase origin master

If you then want to undo some of your changes (but perhaps not all of them) you can use:

git reset SHA_HASH

Then do some adjustment and recommit.

Could not complete the operation due to error 80020101. IE

Switch off compatibility view if you use IE9.

Zero an array in C code

man bzero

NAME
   bzero - write zero-valued bytes

SYNOPSIS
   #include <strings.h>

   void bzero(void *s, size_t n);

DESCRIPTION
   The  bzero()  function sets the first n bytes of the byte area starting
   at s to zero (bytes containing '\0').

How do you disable the unused variable warnings coming out of gcc in 3rd party code I do not wish to edit?

export IGNORE_WARNINGS=1

It does display warnings, but continues with the build

Using NSLog for debugging

Try this piece of code:

NSString *digit = [[sender titlelabel] text];
NSLog(@"%@", digit);

The message means that you have incorrect syntax for using the digit variable. If you're not sending it any message - you don't need any brackets.

Best way to structure a tkinter application?

I personally do not use the objected oriented approach, mostly because it a) only get in the way; b) you will never reuse that as a module.

but something that is not discussed here, is that you must use threading or multiprocessing. Always. otherwise your application will be awful.

just do a simple test: start a window, and then fetch some URL or anything else. changes are your UI will not be updated while the network request is happening. Meaning, your application window will be broken. depend on the OS you are on, but most times, it will not redraw, anything you drag over the window will be plastered on it, until the process is back to the TK mainloop.

jQuery onclick event for <li> tags

In your question it seems that you have span selector with given to every span a seperate class into ul li option and then you have many answers, i.e.

$(document).ready(function()
 {
   $('ul.art-vmenu li').click(function(e) 
    { 
     alert($(this).find("span.t").text());
   });
});

But you need not to use ul.art-vmenu li rather you can use direct ul with the use of on as used in below example :

$(document).ready(function()
 {
  $("ul.art-vmenu").on("click","li", function(){
     alert($(this).find("span.t").text());
  });
});

Difference between SRC and HREF

You should remember when to use everyone and that is it
the href is used with links

<a href="#"></a>
<link rel="stylesheet" href="style.css" />

the src is used with scripts and images

<img src="the_image_link" />
<script type="text/javascript" src="" />

the url is used generally in CSS to include something, for exemple to add a background image

selector { background-image: url('the_image_link'); } 

How do you overcome the HTML form nesting limitation?

I know this is an old question, but HTML5 offers a couple new options.

The first is to separate the form from the toolbar in the markup, add another form for the delete action, and associate the buttons in the toolbar with their respective forms using the form attribute.

<form id="saveForm" action="/post/dispatch/save" method="post">
    <input type="text" name="foo" /> <!-- several of those here -->  
</form>
<form id="deleteForm" action="/post/dispatch/delete" method="post">
    <input type="hidden" value="some_id" />
</form>
<div id="toolbar">
    <input type="submit" name="save" value="Save" form="saveForm" />
    <input type="submit" name="delete" value="Delete" form="deleteForm" />
    <a href="/home/index">Cancel</a>
</div>

This option is quite flexible, but the original post also mentioned that it may be necessary to perform different actions with a single form. HTML5 comes to the rescue, again. You can use the formaction attribute on submit buttons, so different buttons in the same form can submit to different URLs. This example just adds a clone method to the toolbar outside the form, but it would work the same nested in the form.

<div id="toolbar">
    <input type="submit" name="clone" value="Clone" form="saveForm"
           formaction="/post/dispatch/clone" />
</div>

http://www.whatwg.org/specs/web-apps/current-work/#attributes-for-form-submission

The advantage of these new features is that they do all this declaratively without JavaScript. The disadvantage is that they are not supported on older browsers, so you'd have to do some polyfilling for older browsers.

How to create a <style> tag with Javascript?

Here's a script which adds IE-style createStyleSheet() and addRule() methods to browsers which don't have them:

if(typeof document.createStyleSheet === 'undefined') {
    document.createStyleSheet = (function() {
        function createStyleSheet(href) {
            if(typeof href !== 'undefined') {
                var element = document.createElement('link');
                element.type = 'text/css';
                element.rel = 'stylesheet';
                element.href = href;
            }
            else {
                var element = document.createElement('style');
                element.type = 'text/css';
            }

            document.getElementsByTagName('head')[0].appendChild(element);
            var sheet = document.styleSheets[document.styleSheets.length - 1];

            if(typeof sheet.addRule === 'undefined')
                sheet.addRule = addRule;

            if(typeof sheet.removeRule === 'undefined')
                sheet.removeRule = sheet.deleteRule;

            return sheet;
        }

        function addRule(selectorText, cssText, index) {
            if(typeof index === 'undefined')
                index = this.cssRules.length;

            this.insertRule(selectorText + ' {' + cssText + '}', index);
        }

        return createStyleSheet;
    })();
}

You can add external files via

document.createStyleSheet('foo.css');

and dynamically create rules via

var sheet = document.createStyleSheet();
sheet.addRule('h1', 'background: red;');

C++, What does the colon after a constructor mean?

It's called an initialization list. An initializer list is how you pass arguments to your member variables' constructors and for passing arguments to the parent class's constructor.

If you use = to assign in the constructor body, first the default constructor is called, then the assignment operator is called. This is a bit wasteful, and sometimes there's no equivalent assignment operator.

How to find third or n?? maximum salary from salary table?

Showing all 3rd highest salary:

select * from emp where sal=
(SELECT DISTINCT sal FROM emp ORDER BY sal DESC LIMIT 3,1) ;

Showing only 3rd highest salary:

SELECT DISTINCT sal FROM emp ORDER BY sal DESC LIMIT 3,1

Sort matrix according to first column in R

Creating a data.table with key=V1 automatically does this for you. Using Stephan's data foo

> require(data.table)
> foo.dt <- data.table(foo, key="V1")
> foo.dt
   V1  V2
1:  1 349
2:  1 393
3:  1 392
4:  2  94
5:  3  49
6:  3  32
7:  4 459

CAST DECIMAL to INT

There is an important difference between floor() and DIV 1. For negative numbers, they behave differently. DIV 1 returns the integer part (as cast as signed does), while floor(x) returns "the largest integer value not greater than x" (from the manual). So : select floor(-1.1) results in -2, while select -1.1 div 1 results in -1

JSONDecodeError: Expecting value: line 1 column 1

If you look at the output you receive from print() and also in your Traceback, you'll see the value you get back is not a string, it's a bytes object (prefixed by b):

b'{\n  "note":"This file    .....

If you fetch the URL using a tool such as curl -v, you will see that the content type is

Content-Type: application/json; charset=utf-8

So it's JSON, encoded as UTF-8, and Python is considering it a byte stream, not a simple string. In order to parse this, you need to convert it into a string first.

Change the last line of code to this:

info = json.loads(js.decode("utf-8"))

moving committed (but not pushed) changes to a new branch after pull

I stuck with the same issue. I have found easiest solution which I like to share.

1) Create new branch with your changes.

git checkout -b mybranch

2) (Optional) Push new branch code on remote server.

git push origin mybranch

3) Checkout back to master branch.

git checkout master

4) Reset master branch code with remote server and remove local commit.

git reset --hard origin/master

Install php-zip on php 5.6 on Ubuntu

Try either

• sudo apt-get install php-zip or
• sudo apt-get install php5.6-zip

Then, you might have to restart your web server.

• sudo service apache2 restart or
• sudo service nginx restart

If you are installing on centos or fedora OS then use yum in place of apt-get. example:-

sudo yum install php-zip or sudo yum install php5.6-zip and sudo service httpd restart

Undo scaffolding in Rails

Rishav Rastogi is right, and with rails 3.0 or higher its:

rails generate scaffold ...

rails destroy scaffold ...

Select random element in a list of R?

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

Let's take one example, let's say for some reason you want to have a template class:

//test_template.h:
#pragma once
#include <cstdio>

template <class T>
class DemoT
{
public:
    void test()
    {
        printf("ok\n");
    }
};

template <>
void DemoT<int>::test()
{
    printf("int test (int)\n");
}


template <>
void DemoT<bool>::test()
{
    printf("int test (bool)\n");
}

If you compile this code with Visual Studio - it works out of box. gcc will produce linker error (if same header file is used from multiple .cpp files):

error : multiple definition of `DemoT<int>::test()'; your.o: .../test_template.h:16: first defined here

It's possible to move implementation to .cpp file, but then you need to declare class like this -

//test_template.h:
#pragma once
#include <cstdio>

template <class T>
class DemoT
{
public:
    void test()
    {
        printf("ok\n");
    }
};

template <>
void DemoT<int>::test();

template <>
void DemoT<bool>::test();

// Instantiate parametrized template classes, implementation resides on .cpp side.
template class DemoT<bool>;
template class DemoT<int>;

And then .cpp will look like this:

//test_template.cpp:
#include "test_template.h"

template <>
void DemoT<int>::test()
{
    printf("int test (int)\n");
}


template <>
void DemoT<bool>::test()
{
    printf("int test (bool)\n");
}

Without two last lines in header file - gcc will work fine, but Visual studio will produce an error:

 error LNK2019: unresolved external symbol "public: void __cdecl DemoT<int>::test(void)" (?test@?$DemoT@H@@QEAAXXZ) referenced in function

template class syntax is optional in case if you want to expose function via .dll export, but this is applicable only for windows platform - so test_template.h could look like this:

//test_template.h:
#pragma once
#include <cstdio>

template <class T>
class DemoT
{
public:
    void test()
    {
        printf("ok\n");
    }
};

#ifdef _WIN32
    #define DLL_EXPORT __declspec(dllexport) 
#else
    #define DLL_EXPORT
#endif

template <>
void DLL_EXPORT DemoT<int>::test();

template <>
void DLL_EXPORT DemoT<bool>::test();

with .cpp file from previous example.

This however gives more headache to linker, so it's recommended to use previous example if you don't export .dll function.

Passing a method parameter using Task.Factory.StartNew

For passing a single integer I agree with Reed Copsey's answer. If in the future you are going to pass more complicated constucts I personally like to pass all my variables as an Anonymous Type. It will look something like this:

foreach(int id in myIdsToCheck)
{
    Task.Factory.StartNew( (Object obj) => 
        {
           var data = (dynamic)obj;
           CheckFiles(data.id, theBlockingCollection,
               cancelCheckFile.Token, 
               TaskCreationOptions.LongRunning, 
               TaskScheduler.Default);
        }, new { id = id }); // Parameter value
}

You can learn more about it in my blog

What causes the error "undefined reference to (some function)"?

It's a linker error. ld is the linker, so if you get an error message ending with "ld returned 1 exit status", that tells you that it's a linker error.

The error message tells you that none of the object files you're linking against contains a definition for avergecolumns. The reason for that is that the function you've defined is called averagecolumns (in other words: you misspelled the function name when calling the function (and presumably in the header file as well - otherwise you'd have gotten a different error at compile time)).

Where does Visual Studio look for C++ header files?

Visual Studio looks for headers in this order:

• In the current source directory.
• In the Additional Include Directories in the project properties (Project -> [project name] Properties, under C/C++ | General).
• In the Visual Studio C++ Include directories under Tools ? Options ? Projects and Solutions ? VC++ Directories.
• In new versions of Visual Studio (2015+) the above option is deprecated and a list of default include directories is available at Project Properties ? Configuration ? VC++ Directories

In your case, add the directory that the header is to the project properties (Project Properties ? Configuration ? C/C++ ? General ? Additional Include Directories).

Animated GIF in IE stopping

Building on @danfolkes' answer, this worked for me in IE 8 and ASP.NET MVC3.

In our _Layout.cshtml

<body style="min-width: 800px">
    <div id="progress">
        <div style="min-height: 200px">
        </div>
        <div id="throbber">
            <img src="..\..\Content\ajax-loader.gif" alt="Progress" style="display: block;
                margin-left: auto; margin-right: auto" />
        </div>
    </div>
    <div id="main">

<<< content here >>> ...

<script type="text/javascript" language="javascript">
    function ShowThrobber() {
        $('#main').hide();
        $('#progress').show();
        // Work around IE bug which freezes gifs
        if (navigator.appName == 'Microsoft Internet Explorer') {
            // Work around IE bug which freezes gifs
            $("#throbber").html('<img src="../../Content/ajax-loader.gif" alt="Progress" style="display: block; margin-left: auto; margin-right: auto"/>');
         }
</script>
<script type="text/javascript" language="javascript">
    function HideThrobber() {
        $('#main').show();
        $('#progress').hide();
    }
</script>
<script type="text/javascript" language="javascript">
    $(document).ready(function () {
        HideThrobber();
    });
</script>

And in our navigation links:

<input type="submit" value="Finish" class="submit-link" onclick="ShowThrobber()"/>

or

@Html.ActionLink("DoSometthing", "MyController", new { Model.SomeProperty }, new { onclick = "ShowThrobber()" })

How to create an Observable from static data similar to http one in Angular?

This is how you can create a simple observable for static data.

let observable = Observable.create(observer => {
  setTimeout(() => {
    let users = [
      {username:"balwant.padwal",city:"pune"},
      {username:"test",city:"mumbai"}]

    observer.next(users); // This method same as resolve() method from Angular 1
    console.log("am done");
    observer.complete();//to show we are done with our processing
    // observer.error(new Error("error message"));
  }, 2000);

})

to subscribe to it is very easy

observable.subscribe((data)=>{
  console.log(data); // users array display
});

I hope this answer is helpful. We can use HTTP call instead static data.

why $(window).load() is not working in jQuery?

I have to write a whole answer separately since it's hard to add a comment so long to the second answer.

I'm sorry to say this, but the second answer above doesn't work right.

The following three scenarios will show my point:

Scenario 1: Before the following way was deprecated,

  $(window).load(function () {
     alert("Window Loaded.");
  });

if we execute the following two queries:

<script>
   $(window).load(function () {
     alert("Window Loaded.");
   }); 

   $(document).ready(function() {
     alert("Dom Loaded.");
   });
</script>,

the alert (Dom Loaded.) from the second query will show first, and the one (Window Loaded.) from the first query will show later, which is the way it should be.

Scenario 2: But if we execute the following two queries like the second answer above suggests:

<script>
   $(window).ready(function () {
     alert("Window Loaded.");
   }); 

   $(document).ready(function() {
     alert("Dom Loaded.");
   });
</script>,

the alert (Window Loaded.) from the first query will show first, and the one (Dom Loaded.) from the second query will show later, which is NOT right.

Scenario 3: On the other hand, if we execute the following two queries, we'll get the correct result:

<script>
   $(window).on("load", function () {
     alert("Window Loaded.");
   }); 

   $(document).ready(function() {
     alert("Dom Loaded.");
   });
</script>,

that is to say, the alert (Dom Loaded.) from the second query will show first, and the one (Window Loaded.) from the first query will show later, which is the RIGHT result.

In short, the FIRST answer is the CORRECT one:

$(window).on('load', function () {
  alert("Window Loaded.");
});

Create a new line in Java's FileWriter

One can use PrintWriter to wrap the FileWriter, as it has many additional useful methods.

try(PrintWriter pw = new PrintWriter(new FileWriter(new File("file.txt"), false))){
   pw.println();//new line
   pw.print("text");//print without new line
   pw.println(10);//print with new line
   pw.printf("%2.f", 0.567);//print double to 2 decimal places (without new line)
}

Set background color in PHP?

You better use CSS for that, after all, this is what CSS is for. If you don't want to do that, go with Dorwand's answer.

How to delete a character from a string using Python

card = random.choice(cards)
cardsLeft = cards.replace(card, '', 1)

How to remove one character from a string: Here is an example where there is a stack of cards represented as characters in a string. One of them is drawn (import random module for the random.choice() function, that picks a random character in the string). A new string, cardsLeft, is created to hold the remaining cards given by the string function replace() where the last parameter indicates that only one "card" is to be replaced by the empty string...

How can I add new dimensions to a Numpy array?

This worked for me:

image = image[..., None]

Full width layout with twitter bootstrap

Because the accepted answer isn't on the same planet as BS3, I'll share what I'm using to achieve nearly full-width capabilities.

First off, this is cheating. It's not really fluid width - but it appears to be - depending on the size of the screen viewing the site.

The problem with BS3 and fluid width sites is that they have taken this "mobile first" approach, which requires that they define every freaking screen width up to what they consider to be desktop (1200px) I'm working on a laptop with a 1900px wide screen - so I end up with 350px on either side of the content at what BS3 thinks is a desktop sized width.

They have defined 10 screen widths (really only 5, but anyway). I don't really feel comfortable changing those, because they are common widths. So, I chose to define some extra widths for BS to choose from when deciding the width of the container class.

The way I use BS is to take all of the Bootstrap provided LESS files, omit the variables.less file to provide my own, and add one of my own to the end to override the things I want to change. Within my less file, I add the following to achieve 2 common screen width settings:

@media screen and (min-width: 1600px) {
    .container {
        max-width: (1600px - @grid-gutter-width);
    }
}
@media screen and (min-width: 1900px) {
    .container {
        max-width: (1900px - @grid-gutter-width);
    }
}

These two settings set the example for what you need to do to achieve different screen widths. Here, you get full width at 1600px, and 1900px. Any less than 1600 - BS falls back to the 1200px width, then to 768px and so forth - down to phone size.

If you have larger to support, just create more @media screen statements like these. If you're building the CSS instead, you'll want to determine what gutter width was used and subtract it from your target screen width.

Update:

Bootstrap 3.0.1 and up (so far) - it's as easy as setting @container-large-desktop to 100%

How to display and hide a div with CSS?

To hide an element, use:

display: none;
visibility: hidden;

To show an element, use:

display: block;
visibility: visible;

The difference is:

Visibility handles the visibility of the tag, the display handles space it occupies on the page.

If you set the visibility and do not change the display, even if the tags are not seen, it still occupies space.

How to send a header using a HTTP request through a curl call?

man curl:

   -H/--header <header>
          (HTTP)  Extra header to use when getting a web page. You may specify
          any number of extra headers. Note that if you should  add  a  custom
          header that has the same name as one of the internal ones curl would
          use, your externally set header will be used instead of the internal
          one.  This  allows  you  to make even trickier stuff than curl would
          normally do. You should not replace internally set  headers  without
          knowing  perfectly well what you're doing. Remove an internal header
          by giving a replacement without content on the  right  side  of  the
          colon, as in: -H "Host:".

          curl  will  make sure that each header you add/replace get sent with
          the proper end of line marker, you should thus not  add  that  as  a
          part  of the header content: do not add newlines or carriage returns
          they will only mess things up for you.

          See also the -A/--user-agent and -e/--referer options.

          This option can be used multiple times to add/replace/remove  multi-
          ple headers.

Example:

curl --header "X-MyHeader: 123" www.google.com

You can see the request that curl sent by adding the -v option.

Why does writeObject throw java.io.NotSerializableException and how do I fix it?

Make the class serializable by implementing the interface java.io.Serializable.

• java.io.Serializable - Marker Interface which does not have any methods in it.
• Purpose of Marker Interface - to tell the ObjectOutputStream that this object is a serializable object.

How can I bold the fonts of a specific row or cell in an Excel worksheet with C#?

How to Bold entire row 10 example:

workSheet.Cells[10, 1].EntireRow.Font.Bold = true;    

---

More formally:

Microsoft.Office.Interop.Excel.Range rng = workSheet.Cells[10, 1] as Xl.Range;
rng.EntireRow.Font.Bold = true;

---

How to Bold Specific Cell 'A10' for example:

workSheet.Cells[10, 1].Font.Bold = true;

---

Little more formal:

int row = 1;
int column = 1;  /// 1 = 'A' in Excel

Microsoft.Office.Interop.Excel.Range rng = workSheet.Cells[row, column] as Xl.Range;
rng.Font.Bold = true;

Display Last Saved Date on worksheet

You can also simple add the following into the Header or Footer of the Worksheet

Last Saved: &[Date] &[Time]

How can I open two pages from a single click without using JavaScript?

If you have the authority to edit the pages to be opened, you can href to 'A' page and in the A page you can put link to B page in onpageload attribute of body tag.

No 'Access-Control-Allow-Origin' header is present on the requested resource—when trying to get data from a REST API

The problem arose because you added the following code as request header in your front-end :

headers.append('Access-Control-Allow-Origin', 'http://localhost:3000');
headers.append('Access-Control-Allow-Credentials', 'true');

Those headers belong to response, not request. So remove them, including the line :

headers.append('GET', 'POST', 'OPTIONS');

Your request had 'Content-Type: application/json', hence triggered what is called CORS preflight. This caused the browser sent the request with OPTIONS method. See CORS preflight for detailed information.

Therefore in your back-end, you have to handle this preflighted request by returning the response headers which include :

Access-Control-Allow-Origin : http://localhost:3000
Access-Control-Allow-Credentials : true
Access-Control-Allow-Methods : GET, POST, OPTIONS
Access-Control-Allow-Headers : Origin, Content-Type, Accept

Of course, the actual syntax depends on the programming language you use for your back-end.

In your front-end, it should be like so :

function performSignIn() {
    let headers = new Headers();

    headers.append('Content-Type', 'application/json');
    headers.append('Accept', 'application/json');
    headers.append('Authorization', 'Basic ' + base64.encode(username + ":" +  password));
    headers.append('Origin','http://localhost:3000');

    fetch(sign_in, {
        mode: 'cors',
        credentials: 'include',
        method: 'POST',
        headers: headers
    })
    .then(response => response.json())
    .then(json => console.log(json))
    .catch(error => console.log('Authorization failed : ' + error.message));
}

Return multiple values from a function, sub or type?

Ideas :

1. Use pass by reference (ByRef)
2. Build a User Defined Type to hold the stuff you want to return, and return that.
3. Similar to 2 - build a class to represent the information returned, and return objects of that class...

how to use font awesome in own css?

Instructions for Drupal 8 / FontAwesome 5

Create a YOUR_THEME_NAME_HERE.THEME file and place it in your themes directory (ie. your_site_name/themes/your_theme_name)

Paste this into the file, it is PHP code to find the Search Block and change the value to the UNICODE for the FontAwesome icon. You can find other characters at this link https://fontawesome.com/cheatsheet.

<?php
function YOUR_THEME_NAME_HERE_form_search_block_form_alter(&$form, &$form_state) {
  $form['keys']['#attributes']['placeholder'][] = t('Search');
  $form['actions']['submit']['#value'] = html_entity_decode('&#xf002;');
}
?>

Open the CSS file of your theme (ie. your_site_name/themes/your_theme_name/css/styles.css) and then paste this in which will change all input submit text to FontAwesome. Not sure if this will work if you also want to add text in the input button though for just an icon it is fine.

Make sure you import FontAwesome, add this at the top of the CSS file

@import url('https://use.fontawesome.com/releases/v5.0.9/css/all.css');

then add this in the CSS

input#edit-submit {
    font-family: 'Font Awesome\ 5 Free';
    background-color: transparent;
    border: 0;  
}

FLUSH ALL CACHES AND IT SHOULD WORK FINE

Add Google Font Effects

If you are using Google Web Fonts as well you can add also add effects to the icon (see more here https://developers.google.com/fonts/docs/getting_started#enabling_font_effects_beta). You need to import a Google Web Font including the effect(s) you would like to use first in the CSS so it will be

@import url('https://fonts.googleapis.com/css?family=Open+Sans:400,800&effect=3d-float');
@import url('https://use.fontawesome.com/releases/v5.0.9/css/all.css');

Then go back to your .THEME file and add the class for the 3D Float Effect so the code will now add a class to the input. There are different effects available. So just choose the effect you like, change the CSS for the font import and the change the value FONT-EFFECT-3D-FLOAT int the code below to font-effect-WHATEVER_EFFECT_HERE. Note effects are still in Beta and don't work in all browsers so read here before you try it https://developers.google.com/fonts/docs/getting_started#enabling_font_effects_beta

<?php
function YOUR_THEME_NAME_HERE_form_search_block_form_alter(&$form, &$form_state) {
  $form['keys']['#attributes']['placeholder'][] = t('Search');
  $form['actions']['submit']['#value'] = html_entity_decode('&#xf002;');
  $form['actions']['submit']['#attributes']['class'][] = 'font-effect-3d-float';
}
?>

Send Mail to multiple Recipients in java

Internet E-mail address format (RFC 822)

(,)comma separated sequence of addresses

javax.mail - 1.4.7 parse( String[] ) is not allowed. So we have to give comma separated sequence of addresses into InternetAddress objects. Addresses must follow RFC822 syntax.

String toAddress = "[email protected],[email protected]";
InternetAddress.parse( toAddress );

(;) semi-colon separated sequence of addresses « If group of address list is provided with delimeter as ";" then convert to String array using split method to use the following function.

String[] addressList = { "[email protected]", "[email protected]" };

String toGroup = "[email protected];[email protected]";
String[] addressList2 = toGroup.split(";");

setRecipients(message, addressList);

public static void setRecipients(Message message, Object addresslist) throws AddressException, MessagingException {
    if ( addresslist instanceof String ) { // CharSequence
        message.setRecipients(Message.RecipientType.TO, InternetAddress.parse( (String) addresslist  ));
    } else if ( addresslist instanceof String[] ) { // String[] « Array with collection of Strings/
        String[] toAddressList = (String[]) addresslist;
        InternetAddress[] mailAddress_TO = new InternetAddress[ toAddressList.length ];
        for (int i = 0; i < toAddressList.length; i++) {
            mailAddress_TO[i] = new InternetAddress( toAddressList[i] );
        }
        message.setRecipients(Message.RecipientType.TO, mailAddress_TO);
    }
}

Full Example:

public static Properties getMailProperties( boolean addExteraProps ) {
    Properties props = new Properties();
    props.put("mail.transport.protocol", MAIL_TRNSPORT_PROTOCOL);
    props.put("mail.smtp.host", MAIL_SERVER_NAME);
    props.put("mail.smtp.port", MAIL_PORT);

    // Sending Email to the GMail SMTP server requires authentication and SSL.
    props.put("mail.smtp.auth", true);
    if( ENCRYPTION_METHOD.equals("STARTTLS") ) {
        props.put("mail.smtp.starttls.enable", true);
        props.put("mail.smtp.socketFactory.port", SMTP_STARTTLS_PORT); // 587
    } else {
        props.put("mail.smtps.ssl.enable", true);
        props.put("mail.smtp.socketFactory.port", SMTP_SSL_PORT); // 465
    }
    props.put("mail.smtp.socketFactory", SOCKETFACTORY_CLASS);
    return props;
}

public static boolean sendMail(String subject, String contentType, String msg, Object recipients) throws Exception {

    Properties props = getMailProperties( false );
    Session mailSession = Session.getInstance(props, null);
    mailSession.setDebug(true);

    Message message = new MimeMessage( mailSession );
    message.setFrom( new InternetAddress( USER_NAME ) );

    setRecipients(message, recipients);

    message.setSubject( subject );

    String htmlData = "<h1>This is actual message embedded in HTML tags</h1>";
    message.setContent( htmlData, "text/html");

    Transport transport = mailSession.getTransport( MAIL_TRNSPORT_PROTOCOL );
    transport.connect(MAIL_SERVER_NAME, Integer.valueOf(MAIL_PORT), USER_NAME, PASSWORD);
    message.saveChanges(); // don't forget this

    transport.sendMessage(message, message.getAllRecipients());
    transport.close();
}

---

Using Appache SimpleEmail - commons-email-1.3.1

Example: email.addTo( addressList );

public static void sendSimpleMail() throws Exception {
    Email email = new SimpleEmail();
    email.setSmtpPort(587);

    DefaultAuthenticator defaultAuthenticator = new DefaultAuthenticator( USER_NAME, PASSWORD );

    email.setAuthenticator( defaultAuthenticator );
    email.setDebug(false);
    email.setHostName( MAIL_SERVER_NAME );
    email.setFrom( USER_NAME );
    email.setSubject("Hi");
    email.setMsg("This is a test mail ... :-)");

    //email.addTo( "[email protected]", "Yash" );
    String[] toAddressList = { "[email protected]", "[email protected]" }
    email.addTo( addressList );

    email.setTLS(true);
    email.setStartTLSEnabled( true );
    email.send();
    System.out.println("Mail sent!");
}

How can I programmatically get the MAC address of an iphone

#import <sys/socket.h>
#import <net/if_dl.h>
#import <ifaddrs.h>
#import <sys/xattr.h>
#define IFT_ETHER 0x6

...

- (NSString*)macAddress
{
    NSString* result = nil;

    char* macAddressString = (char*)malloc(18);
    if (macAddressString != NULL)
    {
        strcpy(macAddressString, "");

        struct ifaddrs* addrs = NULL;
        struct ifaddrs* cursor;

        if (getifaddrs(&addrs) == 0)
        {
            cursor = addrs;

            while (cursor != NULL)
            {
                if ((cursor->ifa_addr->sa_family == AF_LINK) && (((const struct sockaddr_dl*)cursor->ifa_addr)->sdl_type == IFT_ETHER) && strcmp("en0", cursor->ifa_name) == 0)
                {
                    const struct sockaddr_dl* dlAddr = (const struct sockaddr_dl*) cursor->ifa_addr;
                    const unsigned char* base = (const unsigned char*)&dlAddr->sdl_data[dlAddr->sdl_nlen];

                    for (NSInteger index = 0; index < dlAddr->sdl_alen; index++)
                    {
                        char partialAddr[3];

                        sprintf(partialAddr, "%02X", base[index]);
                        strcat(macAddressString, partialAddr);
                    }
                }

                cursor = cursor->ifa_next;
            }

        }

        result = [[[NSString alloc] initWithUTF8String:macAddressString] autorelease];

        free(macAddressString);
    }

    return result;
}

Generating a unique machine id

You should look into using the MAC address on the network card (if it exists). Those are usually unique but can be fabricated. I've used software that generates its license file based on your network adapter MAC address, so it's considered a fairly reliable way to distinguish between computers.

PostgreSQL: Show tables in PostgreSQL

You can list the tables in the current database with \dt.

Fwiw, \d tablename will show details about the given table, something like show columns from tablename in MySQL, but with a little more information.

Read connection string from web.config

You have to invoke this class on the top of your page or class :

using System.Configuration;

Then you can use this Method that returns the connection string to be ready to passed to the sqlconnection object to continue your work as follows:

    private string ReturnConnectionString()
    {
       // Put the name the Sqlconnection from WebConfig..
        return ConfigurationManager.ConnectionStrings["DBWebConfigString"].ConnectionString;
    }

Just to make a clear clarification this is the value in the web Config:

  <add name="DBWebConfigString" connectionString="....." />   </connectionStrings>

How can I use a C++ library from node.js?

You can use a node.js extension to provide bindings for your C++ code. Here is one tutorial that covers that:

http://syskall.com/how-to-write-your-own-native-nodejs-extension

How to add a custom button to the toolbar that calls a JavaScript function?

This article may be useful too http://mito-team.com/article/2012/collapse-button-for-ckeditor-for-drupal

There are code samples and step-by-step guide about building your own CKEditor plugin with custom button.

Parse json string using JSON.NET

You can use .NET 4's dynamic type and built-in JavaScriptSerializer to do that. Something like this, maybe:

string json = "{\"items\":[{\"Name\":\"AAA\",\"Age\":\"22\",\"Job\":\"PPP\"},{\"Name\":\"BBB\",\"Age\":\"25\",\"Job\":\"QQQ\"},{\"Name\":\"CCC\",\"Age\":\"38\",\"Job\":\"RRR\"}]}";

var jss = new JavaScriptSerializer();

dynamic data = jss.Deserialize<dynamic>(json);

StringBuilder sb = new StringBuilder();

sb.Append("<table>\n  <thead>\n    <tr>\n");

// Build the header based on the keys in the
//  first data item.
foreach (string key in data["items"][0].Keys) {
        sb.AppendFormat("      <th>{0}</th>\n", key);
}

sb.Append("    </tr>\n  </thead>\n  <tbody>\n");

foreach (Dictionary<string, object> item in data["items"]) {
    sb.Append("    <tr>\n");

    foreach (string val in item.Values) {
        sb.AppendFormat("      <td>{0}</td>\n", val);
    }
}

sb.Append("    </tr>\n  </tbody>\n</table>");

string myTable = sb.ToString();

At the end, myTable will hold a string that looks like this:

<table>
    <thead>
        <tr>
            <th>Name</th>
            <th>Age</th>
            <th>Job</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td>AAA</td>
            <td>22</td>
            <td>PPP</td>
        <tr>
            <td>BBB</td>
            <td>25</td>
            <td>QQQ</td>
        <tr>
            <td>CCC</td>
            <td>38</td>
            <td>RRR</td>
        </tr>
    </tbody>
</table>

How to "wait" a Thread in Android

I just add this line exactly as it appears below (if you need a second delay):

try {
    Thread.sleep(1000);
} catch(InterruptedException e) {
    // Process exception
}

I find the catch IS necessary (Your app can crash due to Android OS as much as your own code).

Dialog throwing "Unable to add window — token null is not for an application” with getApplication() as context

For future readers, this should help:

public void show() {
    if(mContext instanceof Activity) {
        Activity activity = (Activity) mContext;
        if (!activity.isFinishing() && !activity.isDestroyed()) {
            dialog.show();
        }
    }
}

Kubernetes pod gets recreated when deleted

In some cases the pods will still not go away even when deleting the deployment. In that case to force delete them you can run the below command.

kubectl delete pods podname --grace-period=0 --force

adb command for getting ip address assigned by operator

download this app from here it will help you to rum all commands. I have run netcfg and it gives the result as attached in screen.

File Permissions and CHMOD: How to set 777 in PHP upon file creation?

If you want to change the permissions of an existing file, use chmod (change mode):

$itWorked = chmod ("/yourdir/yourfile", 0777);

If you want all new files to have certain permissions, you need to look into setting your umode. This is a process setting that applies a default modification to standard modes.

It is a subtractive one. By that, I mean a umode of 022 will give you a default permission of 755 (777 - 022 = 755).

But you should think very carefully about both these options. Files created with that mode will be totally unprotected from changes.

Mongoimport of json file

console:

mongoimport -d dbName -c collectionName dataFile.js 

Understanding inplace=True

If you don't use inplace=True or you use inplace=False you basically get back a copy.

So for instance:

testdf.sort_values(inplace=True, by='volume', ascending=False)

will alter the structure with the data sorted in descending order.

then:

testdf2 = testdf.sort_values( by='volume', ascending=True)

will make testdf2 a copy. the values will all be the same but the sort will be reversed and you will have an independent object.

then given another column, say LongMA and you do:

testdf2.LongMA = testdf2.LongMA -1

the LongMA column in testdf will have the original values and testdf2 will have the decrimented values.

It is important to keep track of the difference as the chain of calculations grows and the copies of dataframes have their own lifecycle.

Java ArrayList clear() function

After data.clear() it will definitely start again from the zero index.

Redirect to specified URL on PHP script completion?

<?
ob_start(); // ensures anything dumped out will be caught

// do stuff here
$url = 'http://example.com/thankyou.php'; // this can be set based on whatever

// clear out the output buffer
while (ob_get_status()) 
{
    ob_end_clean();
}

// no redirect
header( "Location: $url" );
?>

How to get the Touch position in android?

@Override
    public boolean onTouch(View v, MotionEvent event) {
       float x = event.getX();
       float y = event.getY();
       return true;
    }

can we use xpath with BeautifulSoup?

This is a pretty old thread, but there is a work-around solution now, which may not have been in BeautifulSoup at the time.

Here is an example of what I did. I use the "requests" module to read an RSS feed and get its text content in a variable called "rss_text". With that, I run it thru BeautifulSoup, search for the xpath /rss/channel/title, and retrieve its contents. It's not exactly XPath in all its glory (wildcards, multiple paths, etc.), but if you just have a basic path you want to locate, this works.

from bs4 import BeautifulSoup
rss_obj = BeautifulSoup(rss_text, 'xml')
cls.title = rss_obj.rss.channel.title.get_text()

How to save a BufferedImage as a File

1. Download and add imgscalr-lib-x.x.jar and imgscalr-lib-x.x-javadoc.jar to your Projects Libraries.

2. In your code:

   import static org.imgscalr.Scalr.*;
   
   public static BufferedImage resizeBufferedImage(BufferedImage image, Scalr.Method scalrMethod, Scalr.Mode scalrMode, int width, int height)  {
       BufferedImage bi = image;
       bi = resize( image, scalrMethod, scalrMode, width, height);
   return bi;
   }
   
   // Save image:
   ImageIO.write(Scalr.resize(etotBImage, 150), "jpg", new File(myDir));
   

Regular expression to match characters at beginning of line only

Beginning of line or beginning of string?

Start and end of string

/^CTR.*$/

/ = delimiter
^ = start of string
CTR = literal CTR
$ = end of string
.* = zero or more of any character except newline

Start and end of line

/^CTR.*$/m

/ = delimiter
^ = start of line
CTR = literal CTR
$ = end of line
.* = zero or more of any character except newline
m = enables multi-line mode, this sets regex to treat every line as a string, so ^ and $ will match start and end of line

While in multi-line mode you can still match the start and end of the string with \A\Z permanent anchors

/\ACTR.*\Z/m

\A = means start of string
CTR = literal CTR
.* = zero or more of any character except newline
\Z = end of string
m = enables multi-line mode

As such, another way to match the start of the line would be like this:

/(\A|\r|\n|\r\n)CTR.*/

or

/(^|\r|\n|\r\n)CTR.*/

\r = carriage return / old Mac OS newline
\n = line-feed / Unix/Mac OS X newline
\r\n = windows newline

Note, if you are going to use the backslash \ in some program string that supports escaping, like the php double quotation marks "" then you need to escape them first

so to run \r\nCTR.* you would use it as "\\r\\nCTR.*"

How to make --no-ri --no-rdoc the default for gem install?

For Windows users, Ruby doesn't set up .gemrc file. So you have to create .gemrc file in your home directory (echo %USERPROFILE%) and put following line in it:

gem: --no-document

As already mentioned in previous answers, don't use --no-ri and --no-rdoc cause its deprecated. See it yourself:

gem help install

How to center a table of the screen (vertically and horizontally)

For horizontal alignment (No CSS)

Just insert an align attribute inside the table tag

<table align="center"></table

What is the difference between String and StringBuffer in Java?

String                                          StringBuffer

Immutable                                       Mutable
String s=new String("karthik");                StringBuffer sb=new StringBuffer("karthik")
s.concat("reddy");                             sb.append("reddy");
System.out.println(s);                         System.out.println(sb);
O/P:karthik                                    O/P:karthikreddy

--->once we created a String object            ---->once we created a StringBuffer object
we can't perform any changes in the existing  we can perform any changes in the existing
object.If we are trying to perform any        object.It is nothing but mutablity of 
changes with those changes a new object       of a StrongBuffer object
will be created.It is nothing but Immutability
of a String object

Use String--->If you require immutabilty
Use StringBuffer---->If you require mutable + threadsafety
Use StringBuilder--->If you require mutable + with out threadsafety

String s=new String("karthik");
--->here 2 objects will be created one is heap and the other is in stringconstantpool(scp) and s is always pointing to heap object

String s="karthik"; 
--->In this case only one object will be created in scp and s is always pointing to that object only

XSS prevention in JSP/Servlet web application

If you want to make sure that your $ operator does not suffer from XSS hack you can implement ServletContextListener and do some checks there.

The complete solution at: http://pukkaone.github.io/2011/01/03/jsp-cross-site-scripting-elresolver.html

@WebListener
public class EscapeXmlELResolverListener implements ServletContextListener {
    private static final Logger LOG = LoggerFactory.getLogger(EscapeXmlELResolverListener.class);


    @Override
    public void contextInitialized(ServletContextEvent event) {
        LOG.info("EscapeXmlELResolverListener initialized ...");        
        JspFactory.getDefaultFactory()
                .getJspApplicationContext(event.getServletContext())
                .addELResolver(new EscapeXmlELResolver());

    }

    @Override
    public void contextDestroyed(ServletContextEvent event) {
        LOG.info("EscapeXmlELResolverListener destroyed");
    }


    /**
     * {@link ELResolver} which escapes XML in String values.
     */
    public class EscapeXmlELResolver extends ELResolver {

        private ThreadLocal<Boolean> excludeMe = new ThreadLocal<Boolean>() {
            @Override
            protected Boolean initialValue() {
                return Boolean.FALSE;
            }
        };

        @Override
        public Object getValue(ELContext context, Object base, Object property) {

            try {
                    if (excludeMe.get()) {
                        return null;
                    }

                    // This resolver is in the original resolver chain. To prevent
                    // infinite recursion, set a flag to prevent this resolver from
                    // invoking the original resolver chain again when its turn in the
                    // chain comes around.
                    excludeMe.set(Boolean.TRUE);
                    Object value = context.getELResolver().getValue(
                            context, base, property);

                    if (value instanceof String) {
                        value = StringEscapeUtils.escapeHtml4((String) value);
                    }
                    return value;
            } finally {
                excludeMe.remove();
            }
        }

        @Override
        public Class<?> getCommonPropertyType(ELContext context, Object base) {
            return null;
        }

        @Override
        public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base){
            return null;
        }

        @Override
        public Class<?> getType(ELContext context, Object base, Object property) {
            return null;
        }

        @Override
        public boolean isReadOnly(ELContext context, Object base, Object property) {
            return true;
        }

        @Override
        public void setValue(ELContext context, Object base, Object property, Object value){
            throw new UnsupportedOperationException();
        }

    }

}

Again: This only guards the $. Please also see other answers.

How do I revert back to an OpenWrt router configuration?

You can run this command for making a factory reset:

killall dropbear uhttpd; sleep 1; mtd -r erase rootfs_data

How to name an object within a PowerPoint slide?

THIS IS NOT AN ANSWER TO THE ORIGINAL QUESTION, IT'S AN ANSWER TO @Teddy's QUESTION IN @Dudi's ANSWER'S COMMENTS

Here's a way to list id's in the active presentation to the immediate window (Ctrl + G) in VBA editor:

Sub ListAllShapes()

    Dim curSlide As Slide
    Dim curShape As Shape

    For Each curSlide In ActivePresentation.Slides
        Debug.Print curSlide.SlideID
        For Each curShape In curSlide.Shapes

                If curShape.TextFrame.HasText Then
                    Debug.Print curShape.Id
                End If

        Next curShape
    Next curSlide
End Sub

How to specify the JDK version in android studio?

This is old question but still my answer may help someone

For checking Java version in android studio version , simply open Terminal of Android Studio and type

java -version 

This will display java version installed in android studio

How do you change the server header returned by nginx?

Nginx-extra package is deprecated now.

The following therefore did now work for me as i tried installing various packages more_set_headers 'Server: My Very Own Server';

You can just do the following and no server or version information will be sent back

    server_tokens '';

if you just want to remove the version number this works

   server_tokens off;

How to count rows with SELECT COUNT(*) with SQLAlchemy?

I needed to do a count of a very complex query with many joins. I was using the joins as filters, so I only wanted to know the count of the actual objects. count() was insufficient, but I found the answer in the docs here:

http://docs.sqlalchemy.org/en/latest/orm/tutorial.html

The code would look something like this (to count user objects):

from sqlalchemy import func

session.query(func.count(User.id)).scalar() 

#pragma pack effect

You'd likely only want to use this if you were coding to some hardware (e.g. a memory mapped device) which had strict requirements for register ordering and alignment.

However, this looks like a pretty blunt tool to achieve that end. A better approach would be to code a mini-driver in assembler and give it a C calling interface rather than fumbling around with this pragma.

How to beautify JSON in Python?

Use the python tool library

Command line: python -mjson.tool

In code: http://docs.python.org/library/json.html

Concat all strings inside a List<string> using LINQ

String.Join(delimiter, list);

is sufficient.

How do I get next month date from today's date and insert it in my database?

Be careful, because sometimes strtotime("+1 months") can skip month numbers.

Example:

$today = date("Y-m-d"); // 2012-01-30
$next_month = date("Y-m-d", strtotime("$today +1 month"));

If today is January, next month should be February which has 28 or 29 days, but PHP will return March as next month, not February.

URL to load resources from the classpath in Java

Intro and basic Implementation

First up, you're going to need at least a URLStreamHandler. This will actually open the connection to a given URL. Notice that this is simply called Handler; this allows you to specify java -Djava.protocol.handler.pkgs=org.my.protocols and it will automatically be picked up, using the "simple" package name as the supported protocol (in this case "classpath").

Usage

new URL("classpath:org/my/package/resource.extension").openConnection();

Code

package org.my.protocols.classpath;

import java.io.IOException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLStreamHandler;

/** A {@link URLStreamHandler} that handles resources on the classpath. */
public class Handler extends URLStreamHandler {
    /** The classloader to find resources from. */
    private final ClassLoader classLoader;

    public Handler() {
        this.classLoader = getClass().getClassLoader();
    }

    public Handler(ClassLoader classLoader) {
        this.classLoader = classLoader;
    }

    @Override
    protected URLConnection openConnection(URL u) throws IOException {
        final URL resourceUrl = classLoader.getResource(u.getPath());
        return resourceUrl.openConnection();
    }
}

Launch issues

If you're anything like me, you don't want to rely on a property being set in the launch to get you somewhere (in my case, I like to keep my options open like Java WebStart - which is why I need all this).

Workarounds/Enhancements

Manual code Handler specification

If you control the code, you can do

new URL(null, "classpath:some/package/resource.extension", new org.my.protocols.classpath.Handler(ClassLoader.getSystemClassLoader()))

and this will use your handler to open the connection.

But again, this is less than satisfactory, as you don't need a URL to do this - you want to do this because some lib you can't (or don't want to) control wants urls...

JVM Handler registration

The ultimate option is to register a URLStreamHandlerFactory that will handle all urls across the jvm:

package my.org.url;

import java.net.URLStreamHandler;
import java.net.URLStreamHandlerFactory;
import java.util.HashMap;
import java.util.Map;

class ConfigurableStreamHandlerFactory implements URLStreamHandlerFactory {
    private final Map<String, URLStreamHandler> protocolHandlers;

    public ConfigurableStreamHandlerFactory(String protocol, URLStreamHandler urlHandler) {
        protocolHandlers = new HashMap<String, URLStreamHandler>();
        addHandler(protocol, urlHandler);
    }

    public void addHandler(String protocol, URLStreamHandler urlHandler) {
        protocolHandlers.put(protocol, urlHandler);
    }

    public URLStreamHandler createURLStreamHandler(String protocol) {
        return protocolHandlers.get(protocol);
    }
}

To register the handler, call URL.setURLStreamHandlerFactory() with your configured factory. Then do new URL("classpath:org/my/package/resource.extension") like the first example and away you go.

JVM Handler Registration Issue

Note that this method may only be called once per JVM, and note well that Tomcat will use this method to register a JNDI handler (AFAIK). Try Jetty (I will be); at worst, you can use the method first and then it has to work around you!

License

I release this to the public domain, and ask that if you wish to modify that you start a OSS project somewhere and comment here with the details. A better implementation would be to have a URLStreamHandlerFactory that uses ThreadLocals to store URLStreamHandlers for each Thread.currentThread().getContextClassLoader(). I'll even give you my modifications and test classes.

How to detect simple geometric shapes using OpenCV

You can also use template matching to detect shapes inside an image.

How to download all dependencies and packages to directory

I used apt-cache depends package to get all required packages in any case if the are already installed on system or not. So it will work always correct.
Because the command apt-cache works different, depending on language, you have to try this command on your system and adapt the command. apt-cache depends yourpackage
On an englisch system you get:

$ apt-cache depends yourpackage
node
  Depends: libax25
  Depends: libc6

On an german system you get: node

  Hängt ab von: libax25
  Hängt ab von: libc6

The englisch version with the term:
"Depends:"
You have to change the term "yourpackage" to your wish twice in this command, take care of this!

$ sudo apt-get --print-uris --yes -d --reinstall install yourpackage $(apt-cache depends yourpackage | grep "  Depends:" |  sed 's/  Depends://' | sed ':a;N;$!ba;s/\n//g') | grep ^\' | cut -d\' -f2 >downloads.list

And the german version with the term:
"Hängt ab von:"
You have to change the term "yourpackage" to your wish twice in this command, take care of this!
This text is used twice in this command, if you want to adapt it to your language take care of this!

$ sudo apt-get --print-uris --yes -d --reinstall install yourpackage $(apt-cache depends yourpackage | grep "Hängt ab von:" |  sed 's/  Hängt ab von://' | sed ':a;N;$!ba;s/\n//g') | grep ^\' | cut -d\' -f2 >downloads.list

You get the list of links in downloads.list
Check the list, go to your folder and run the list:

$ cd yourpathToYourFolder

$ wget --input-file downloads.list

All your required packages are in:

$ ls yourpathToYourFolder

How to prevent line-break in a column of a table cell (not a single cell)?

Put non-breaking spaces in your text instead of normal spaces. On Ubuntu I do this with (Compose Key)-space-space.

Git push error: Unable to unlink old (Permission denied)

Some files are write-protected that even git cannot over write it. Change the folder permission to allow writing e.g. sudo chmod 775 foldername

And then execute

git pull 

again

Position DIV relative to another DIV?

You need to set postion:relative of outer DIV and position:absolute of inner div.
Try this. Here is the Demo

#one
{
    background-color: #EEE;
    margin: 62px 258px;
    padding: 5px;
    width: 200px;
    position: relative;   
}

#two
{
    background-color: #F00;
    display: inline-block;
    height: 30px;
    position: absolute;
    width: 100px;
    top:10px;
}?

Is Constructor Overriding Possible?

Constructor looks like a method but name should be as class name and no return value.

Overriding means what we have declared in Super class, that exactly we have to declare in Sub class it is called Overriding. Super class name and Sub class names are different.

If you trying to write Super class Constructor in Sub class, then Sub class will treat that as a method not constructor because name should not match with Sub class name. And it will give an compilation error that methods does not have return value. So we should declare as void, then only it will compile.

Flask - Calling python function on button OnClick event

It sounds like you want to use this web application as a remote control for your robot, and a core issue is that you won't want a page reload every time you perform an action, in which case, the last link you posted answers your problem.

I think you may be misunderstanding a few things about Flask. For one, you can't nest multiple functions in a single route. You're not making a set of functions available for a particular route, you're defining the one specific thing the server will do when that route is called.

With that in mind, you would be able to solve your problem with a page reload by changing your app.py to look more like this:

from flask import Flask, render_template, Response, request, redirect, url_for
app = Flask(__name__)

@app.route("/")
def index():
    return render_template('index.html')

@app.route("/forward/", methods=['POST'])
def move_forward():
    #Moving forward code
    forward_message = "Moving Forward..."
    return render_template('index.html', forward_message=forward_message);

Then in your html, use this:

<form action="/forward/" method="post">
    <button name="forwardBtn" type="submit">Forward</button>
</form>

...To execute your moving forward code. And include this:

{{ forward_message }} 

... where you want the moving forward message to appear on your template.

This will cause your page to reload, which is inevitable without using AJAX and Javascript.