Programs & Examples On #Yfrog

How to remove the last element added into the List?

if you need to do it more often , you can even create your own method for pop the last element; something like this:

public void pop(List<string> myList) {
    myList.RemoveAt(myList.Count - 1);
}

or even instead of void you can return the value like:

public string pop (List<string> myList) {
    // first assign the  last value to a seperate string 
    string extractedString = myList(myList.Count - 1);
    // then remove it from list
    myList.RemoveAt(myList.Count - 1);
    // then return the value 
    return extractedString;
}

just notice that the second method's return type is not void , it is string b/c we want that function to return us a string ...

How to search a Git repository by commit message?

If the change is not too old, you can do,

git reflog

and then checkout the commit id

What are the differences between using the terminal on a mac vs linux?

If you did a new or clean install of OS X version 10.3 or more recent, the default user terminal shell is bash.

Bash is essentially an enhanced and GNU freeware version of the original Bourne shell, sh. If you have previous experience with bash (often the default on GNU/Linux installations), this makes the OS X command-line experience familiar, otherwise consider switching your shell either to tcsh or to zsh, as some find these more user-friendly.

If you upgraded from or use OS X version 10.2.x, 10.1.x or 10.0.x, the default user shell is tcsh, an enhanced version of csh('c-shell'). Early implementations were a bit buggy and the programming syntax a bit weird so it developed a bad rap.

There are still some fundamental differences between mac and linux as Gordon Davisson so aptly lists, for example no useradd on Mac and ifconfig works differently.

The following table is useful for knowing the various unix shells.

sh      The original Bourne shell   Present on every unix system 
ksh     Original Korn shell         Richer shell programming environment than sh 
csh     Original C-shell            C-like syntax; early versions buggy 
tcsh    Enhanced C-shell            User-friendly and less buggy csh implementation 
bash    GNU Bourne-again shell      Enhanced and free sh implementation 
zsh     Z shell                     Enhanced, user-friendly ksh-like shell

You may also find these guides helpful:

http://homepage.mac.com/rgriff/files/TerminalBasics.pdf

http://guides.macrumors.com/Terminal
http://www.ofb.biz/safari/article/476.html

On a final note, I am on Linux (Ubuntu 11) and Mac osX so I use bash and the thing I like the most is customizing the .bashrc (source'd from .bash_profile on OSX) file with aliases, some examples below. I now placed all my aliases in a separate .bash_aliases file and include it with:

if [ -f ~/.bash_aliases ]; then
    . ~/.bash_aliases
fi

in the .bashrc or .bash_profile file.

Note that this is an example of a mac-linux difference because on a Mac you can't have the --color=auto. The first time I did this (without knowing) I redefined ls to be invalid which was a bit alarming until I removed --auto-color !

You may also find https://unix.stackexchange.com/q/127799/10043 useful

# ~/.bash_aliases
# ls variants
#alias l='ls -CF' 
alias la='ls -A' 
alias l='ls -alFtr' 
alias lsd='ls -d .*' 
# Various
alias h='history | tail'
alias hg='history | grep'
alias mv='mv -i' 
alias zap='rm -i'
# One letter quickies:
alias p='pwd'
alias x='exit'
alias {ack,ak}='ack-grep'
# Directories
alias s='cd ..'
alias play='cd ~/play/'
# Rails
alias src='script/rails console'
alias srs='script/rails server'
alias raked='rake db:drop db:create db:migrate db:seed' 
alias rvm-restart='source '\''/home/durrantm/.rvm/scripts/rvm'\'''
alias rrg='rake routes | grep '
alias rspecd='rspec --drb '
#
# DropBox - syncd
WORKBASE="~/Dropbox/97_2012/work"
alias work="cd $WORKBASE"
alias code="cd $WORKBASE/ror/code"
#
# DropNot - NOT syncd !
WORKBASE_GIT="~/Dropnot"
alias {dropnot,not}="cd $WORKBASE_GIT"
alias {webs,ww}="cd $WORKBASE_GIT/webs"
alias {setups,docs}="cd $WORKBASE_GIT/setups_and_docs"
alias {linker,lnk}="cd $WORKBASE_GIT/webs/rails_v3/linker"
#
# git
alias {gsta,gst}='git status' 
# Warning: gst conflicts with gnu-smalltalk (when used).
alias {gbra,gb}='git branch'
alias {gco,go}='git checkout'
alias {gcob,gob}='git checkout -b '
alias {gadd,ga}='git add '
alias {gcom,gc}='git commit'
alias {gpul,gl}='git pull '
alias {gpus,gh}='git push '
alias glom='git pull origin master'
alias ghom='git push origin master'
alias gg='git grep '
#
# vim
alias v='vim'
#
# tmux
alias {ton,tn}='tmux set -g mode-mouse on'
alias {tof,tf}='tmux set -g mode-mouse off'
#
# dmc
alias {dmc,dm}='cd ~/Dropnot/webs/rails_v3/dmc/'
alias wf='cd ~/Dropnot/webs/rails_v3/dmc/dmWorkflow'
alias ws='cd ~/Dropnot/webs/rails_v3/dmc/dmStaffing'

Selenium Webdriver move mouse to Point

If you are using a RemoteWebDriver, you can cast WebElement into RemoteWebElement. You can then call getCoordinates() on that object to get the coordinates.

        WebElement el = driver.findElementById("elementId");
        Coordinates c = ((RemoteWebElement)el).getCoordinates();
        driver.getMouse().mouseMove(c);

How do I set a value in CKEditor with Javascript?

I tried this and worked for me.

success: function (response) {
    document.getElementById('packageItems').value = response.package_items;

    ClassicEditor
    .create(document.querySelector('#packageItems'), {
        removePlugins: ['dragdrop']
    })
    .then(function (editor) {
        editor.setData(response.package_items);
    })
    .catch(function (err) {
        console.error(err);
    });
},

set height of imageview as matchparent programmatically

You can try this incase you would like to match parent. The dimensions arrangement is width and height inorder

web = new WebView(this);
        web.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));

Array from dictionary keys in swift

With Swift 3, Dictionary has a keys property. keys has the following declaration:

var keys: LazyMapCollection<Dictionary<Key, Value>, Key> { get }

A collection containing just the keys of the dictionary.

Note that LazyMapCollection that can easily be mapped to an Array with Array's init(_:) initializer.


From NSDictionary to [String]

The following iOS AppDelegate class snippet shows how to get an array of strings ([String]) using keys property from a NSDictionary:

enter image description here

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    let string = Bundle.main.path(forResource: "Components", ofType: "plist")!
    if let dict = NSDictionary(contentsOfFile: string) as? [String : Int] {
        let lazyMapCollection = dict.keys
        
        let componentArray = Array(lazyMapCollection)
        print(componentArray)
        // prints: ["Car", "Boat"]
    }
    
    return true
}

From [String: Int] to [String]

In a more general way, the following Playground code shows how to get an array of strings ([String]) using keys property from a dictionary with string keys and integer values ([String: Int]):

let dictionary = ["Gabrielle": 49, "Bree": 32, "Susan": 12, "Lynette": 7]
let lazyMapCollection = dictionary.keys

let stringArray = Array(lazyMapCollection)
print(stringArray)
// prints: ["Bree", "Susan", "Lynette", "Gabrielle"]

From [Int: String] to [String]

The following Playground code shows how to get an array of strings ([String]) using keys property from a dictionary with integer keys and string values ([Int: String]):

let dictionary = [49: "Gabrielle", 32: "Bree", 12: "Susan", 7: "Lynette"]
let lazyMapCollection = dictionary.keys
    
let stringArray = Array(lazyMapCollection.map { String($0) })
// let stringArray = Array(lazyMapCollection).map { String($0) } // also works
print(stringArray)
// prints: ["32", "12", "7", "49"]

How to sort an array in descending order in Ruby

It's always enlightening to do a benchmark on the various suggested answers. Here's what I found out:

#!/usr/bin/ruby

require 'benchmark'

ary = []
1000.times { 
  ary << {:bar => rand(1000)} 
}

n = 500
Benchmark.bm(20) do |x|
  x.report("sort")               { n.times { ary.sort{ |a,b| b[:bar] <=> a[:bar] } } }
  x.report("sort reverse")       { n.times { ary.sort{ |a,b| a[:bar] <=> b[:bar] }.reverse } }
  x.report("sort_by -a[:bar]")   { n.times { ary.sort_by{ |a| -a[:bar] } } }
  x.report("sort_by a[:bar]*-1") { n.times { ary.sort_by{ |a| a[:bar]*-1 } } }
  x.report("sort_by.reverse!")   { n.times { ary.sort_by{ |a| a[:bar] }.reverse } }
end

                          user     system      total        real
sort                  3.960000   0.010000   3.970000 (  3.990886)
sort reverse          4.040000   0.000000   4.040000 (  4.038849)
sort_by -a[:bar]      0.690000   0.000000   0.690000 (  0.692080)
sort_by a[:bar]*-1    0.700000   0.000000   0.700000 (  0.699735)
sort_by.reverse!      0.650000   0.000000   0.650000 (  0.654447)

I think it's interesting that @Pablo's sort_by{...}.reverse! is fastest. Before running the test I thought it would be slower than "-a[:bar]" but negating the value turns out to take longer than it does to reverse the entire array in one pass. It's not much of a difference, but every little speed-up helps.


Please note that these results are different in Ruby 1.9

Here are results for Ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-darwin10.8.0]:

                           user     system      total        real
sort                   1.340000   0.010000   1.350000 (  1.346331)
sort reverse           1.300000   0.000000   1.300000 (  1.310446)
sort_by -a[:bar]       0.430000   0.000000   0.430000 (  0.429606)
sort_by a[:bar]*-1     0.420000   0.000000   0.420000 (  0.414383)
sort_by.reverse!       0.400000   0.000000   0.400000 (  0.401275)

These are on an old MacBook Pro. Newer, or faster machines, will have lower values, but the relative differences will remain.


Here's a bit updated version on newer hardware and the 2.1.1 version of Ruby:

#!/usr/bin/ruby

require 'benchmark'

puts "Running Ruby #{RUBY_VERSION}"

ary = []
1000.times {
  ary << {:bar => rand(1000)}
}

n = 500

puts "n=#{n}"
Benchmark.bm(20) do |x|
  x.report("sort")               { n.times { ary.dup.sort{ |a,b| b[:bar] <=> a[:bar] } } }
  x.report("sort reverse")       { n.times { ary.dup.sort{ |a,b| a[:bar] <=> b[:bar] }.reverse } }
  x.report("sort_by -a[:bar]")   { n.times { ary.dup.sort_by{ |a| -a[:bar] } } }
  x.report("sort_by a[:bar]*-1") { n.times { ary.dup.sort_by{ |a| a[:bar]*-1 } } }
  x.report("sort_by.reverse")    { n.times { ary.dup.sort_by{ |a| a[:bar] }.reverse } }
  x.report("sort_by.reverse!")   { n.times { ary.dup.sort_by{ |a| a[:bar] }.reverse! } }
end

# >> Running Ruby 2.1.1
# >> n=500
# >>                            user     system      total        real
# >> sort                   0.670000   0.000000   0.670000 (  0.667754)
# >> sort reverse           0.650000   0.000000   0.650000 (  0.655582)
# >> sort_by -a[:bar]       0.260000   0.010000   0.270000 (  0.255919)
# >> sort_by a[:bar]*-1     0.250000   0.000000   0.250000 (  0.258924)
# >> sort_by.reverse        0.250000   0.000000   0.250000 (  0.245179)
# >> sort_by.reverse!       0.240000   0.000000   0.240000 (  0.242340)

New results running the above code using Ruby 2.2.1 on a more recent Macbook Pro. Again, the exact numbers aren't important, it's their relationships:

Running Ruby 2.2.1
n=500
                           user     system      total        real
sort                   0.650000   0.000000   0.650000 (  0.653191)
sort reverse           0.650000   0.000000   0.650000 (  0.648761)
sort_by -a[:bar]       0.240000   0.010000   0.250000 (  0.245193)
sort_by a[:bar]*-1     0.240000   0.000000   0.240000 (  0.240541)
sort_by.reverse        0.230000   0.000000   0.230000 (  0.228571)
sort_by.reverse!       0.230000   0.000000   0.230000 (  0.230040)

Updated for Ruby 2.7.1 on a Mid-2015 MacBook Pro:

Running Ruby 2.7.1
n=500     
                           user     system      total        real
sort                   0.494707   0.003662   0.498369 (  0.501064)
sort reverse           0.480181   0.005186   0.485367 (  0.487972)
sort_by -a[:bar]       0.121521   0.003781   0.125302 (  0.126557)
sort_by a[:bar]*-1     0.115097   0.003931   0.119028 (  0.122991)
sort_by.reverse        0.110459   0.003414   0.113873 (  0.114443)
sort_by.reverse!       0.108997   0.001631   0.110628 (  0.111532)

...the reverse method doesn't actually return a reversed array - it returns an enumerator that just starts at the end and works backwards.

The source for Array#reverse is:

               static VALUE
rb_ary_reverse_m(VALUE ary)
{
    long len = RARRAY_LEN(ary);
    VALUE dup = rb_ary_new2(len);

    if (len > 0) {
        const VALUE *p1 = RARRAY_CONST_PTR_TRANSIENT(ary);
        VALUE *p2 = (VALUE *)RARRAY_CONST_PTR_TRANSIENT(dup) + len - 1;
        do *p2-- = *p1++; while (--len > 0);
    }
    ARY_SET_LEN(dup, RARRAY_LEN(ary));
    return dup;
}

do *p2-- = *p1++; while (--len > 0); is copying the pointers to the elements in reverse order if I remember my C correctly, so the array is reversed.

How the single threaded non blocking IO model works in Node.js

Node.js is built upon libuv, a cross-platform library that abstracts apis/syscalls for asynchronous (non-blocking) input/output provided by the supported OSes (Unix, OS X and Windows at least).

Asynchronous IO

In this programming model open/read/write operation on devices and resources (sockets, filesystem, etc.) managed by the file-system don't block the calling thread (as in the typical synchronous c-like model) and just mark the process (in kernel/OS level data structure) to be notified when new data or events are available. In case of a web-server-like app, the process is then responsible to figure out which request/context the notified event belongs to and proceed processing the request from there. Note that this will necessarily mean you'll be on a different stack frame from the one that originated the request to the OS as the latter had to yield to a process' dispatcher in order for a single threaded process to handle new events.

The problem with the model I described is that it's not familiar and hard to reason about for the programmer as it's non-sequential in nature. "You need to make request in function A and handle the result in a different function where your locals from A are usually not available."

Node's model (Continuation Passing Style and Event Loop)

Node tackles the problem leveraging javascript's language features to make this model a little more synchronous-looking by inducing the programmer to employ a certain programming style. Every function that requests IO has a signature like function (... parameters ..., callback) and needs to be given a callback that will be invoked when the requested operation is completed (keep in mind that most of the time is spent waiting for the OS to signal the completion - time that can be spent doing other work). Javascript's support for closures allows you to use variables you've defined in the outer (calling) function inside the body of the callback - this allows to keep state between different functions that will be invoked by the node runtime independently. See also Continuation Passing Style.

Moreover, after invoking a function spawning an IO operation the calling function will usually return control to node's event loop. This loop will invoke the next callback or function that was scheduled for execution (most likely because the corresponding event was notified by the OS) - this allows the concurrent processing of multiple requests.

You can think of node's event loop as somewhat similar to the kernel's dispatcher: the kernel would schedule for execution a blocked thread once its pending IO is completed while node will schedule a callback when the corresponding event has occured.

Highly concurrent, no parallelism

As a final remark, the phrase "everything runs in parallel except your code" does a decent job of capturing the point that node allows your code to handle requests from hundreds of thousands open socket with a single thread concurrently by multiplexing and sequencing all your js logic in a single stream of execution (even though saying "everything runs in parallel" is probably not correct here - see Concurrency vs Parallelism - What is the difference?). This works pretty well for webapp servers as most of the time is actually spent on waiting for network or disk (database / sockets) and the logic is not really CPU intensive - that is to say: this works well for IO-bound workloads.

Converting from hex to string

If you need the result as byte array, you should pass it directly without changing it to a string, then change it back to bytes. In your example the (f.e.: 0x31 = 1) is the ASCII codes. In that case to convert a string (of hex values) to ASCII values use: Encoding.ASCII.GetString(byte[])

        byte[] data = new byte[] { 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x30 };
        string ascii=Encoding.ASCII.GetString(data);
        Console.WriteLine(ascii);

The console will display: 1234567890

MySQL 8.0 - Client does not support authentication protocol requested by server; consider upgrading MySQL client

Just Run MySQL Server Installer and Reconfigure the My SQL Server...This worked for me.

UIImage: Resize, then Crop

+ (UIImage *)scaleImage:(UIImage *)image toSize:(CGSize)targetSize {
    //If scaleFactor is not touched, no scaling will occur      
    CGFloat scaleFactor = 1.0;

    //Deciding which factor to use to scale the image (factor = targetSize / imageSize)
    if (image.size.width > targetSize.width || image.size.height > targetSize.height)
        if (!((scaleFactor = (targetSize.width / image.size.width)) > (targetSize.height / image.size.height))) //scale to fit width, or
            scaleFactor = targetSize.height / image.size.height; // scale to fit heigth.

    UIGraphicsBeginImageContext(targetSize); 

    //Creating the rect where the scaled image is drawn in
    CGRect rect = CGRectMake((targetSize.width - image.size.width * scaleFactor) / 2,
                             (targetSize.height -  image.size.height * scaleFactor) / 2,
                             image.size.width * scaleFactor, image.size.height * scaleFactor);

    //Draw the image into the rect
    [image drawInRect:rect];

    //Saving the image, ending image context
    UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return scaledImage;
}

I propose this one. Isn't she a beauty? ;)

How can I install MacVim on OS X?

  • Step 1. Install homebrew from here: http://brew.sh
  • Step 1.1. Run export PATH=/usr/local/bin:$PATH
  • Step 2. Run brew update
  • Step 3. Run brew install vim && brew install macvim
  • Step 4. Run brew link macvim

You now have the latest versions of vim and macvim managed by brew. Run brew update && brew upgrade every once in a while to upgrade them.

This includes the installation of the CLI mvim and the mac application (which both point to the same thing).

I use this setup and it works like a charm. Brew even takes care of installing vim with the preferable options.

Retrieve specific commit from a remote Git repository

You can simply fetch a single commit of a remote repo with

git fetch <repo> <commit>

where,

  • <repo> can be a remote repo name (e.g. origin) or even a remote repo URL (e.g. https://git.foo.com/myrepo.git)
  • <commit> can be the SHA1 commit

for example

git fetch https://git.foo.com/myrepo.git 0a071603d87e0b89738599c160583a19a6d95545

after you fetched the commit (and the missing ancestors) you can simply checkout it with

git checkout FETCH_HEAD

Note that this will bring you in the "detached head" state.

Remove Fragment Page from ViewPager in Android

You can combine both for better :

private class MyPagerAdapter extends FragmentStatePagerAdapter {

    //... your existing code

    @Override
    public int getItemPosition(Object object){

      if(Any_Reason_You_WantTo_Update_Positions) //this includes deleting or adding pages
 return PagerAdapter.POSITION_NONE;
    }
else
return PagerAdapter.POSITION_UNCHANGED; //this ensures high performance in other operations such as editing list items.

}

Maven Error: Could not find or load main class

specify the main class location in pom under plugins

<build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>2.4</version>
                <configuration>
                    <archive>
                        <index>true</index>
                        <manifest>
                            <mainClass>com.example.hadoop.wordCount.WordCountApp</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
        </plugins>
    </build>

How to set background color of a View

view.setBackgroundColor(R.color.primaryColor);

Adds color to previous color value, so i have a different color.

What works for me is :

view.setBackgroundResource(R.color.primaryColor);

Python: For each list element apply a function across the list

You can do this using list comprehensions and min() (Python 3.0 code):

>>> nums = [1,2,3,4,5]
>>> [(x,y) for x in nums for y in nums]
[(1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (2, 1), (2, 2), (2, 3), (2, 4), (2, 5), (3, 1), (3, 2), (3, 3), (3, 4), (3, 5), (4, 1), (4, 2), (4, 3), (4, 4), (4, 5), (5, 1), (5, 2), (5, 3), (5, 4), (5, 5)]
>>> min(_, key=lambda pair: pair[0]/pair[1])
(1, 5)

Note that to run this on Python 2.5 you'll need to either make one of the arguments a float, or do from __future__ import division so that 1/5 correctly equals 0.2 instead of 0.

How to use graphics.h in codeblocks?

It is a tradition to use Turbo C for graphic in C/C++. But it’s also a pain in the neck. We are using Code::Blocks IDE, which will ease out our work.

Steps to run graphics code in CodeBlocks:

  1. Install Code::Blocks
  2. Download the required header files
  3. Include graphics.h and winbgim.h
  4. Include libbgi.a
  5. Add Link Libraries in Linker Setting
  6. include graphics.h and Save code in cpp extension

To test the setting copy paste run following code:

#include <graphics.h>
int main( )
{
    initwindow(400, 300, "First Sample");
    circle(100, 50, 40);
    while (!kbhit( ))
    {
        delay(200);
    }
    return 0;
}

Here is a complete setup instruction for Code::Blocks

How to include graphics.h in CodeBlocks?

Android SDK installation doesn't find JDK

Windows 8 running the x64 SDK.

  1. Download the latest JDK from here: Oracle JDK
  2. Once downloaded and extracted go into the JDK file at C:\Program Files\Java\jdk1.7.0_80\bin and double click on the java Application file (it's the only one called just java). This will briefly open the command line.
  3. Begin the process of installing Android Studio again, from scratch. It should automatically detect the SDK now.

For whatever reason Android Studio wouldn't detect it no matter what I put in manually or searched using the browse option.

Pressing back would not work.

Reporting the error would not work.

Adding JAVA_HOME or other suggestions to the C:... would not work.

It was only beginning the installation of Android Studio again after running the java file that it worked.

Easy way to print Perl array? (with a little formatting)

Just use join():

# assuming @array is your array:
print join(", ", @array);

Can I apply multiple background colors with CSS3?

Yes its possible! and you can use as many colors and images as you desire, here is the right way:

_x000D_
_x000D_
body{_x000D_
/* Its, very important to set the background repeat to: no-repeat */_x000D_
background-repeat:no-repeat; _x000D_
_x000D_
background-image:  _x000D_
/* 1) An image              */ url(http://lorempixel.com/640/100/nature/John3-16/), _x000D_
/* 2) Gradient              */ linear-gradient(to right, RGB(0, 0, 0), RGB(255, 255, 255)), _x000D_
/* 3) Color(using gradient) */ linear-gradient(to right, RGB(110, 175, 233), RGB(110, 175, 233));_x000D_
_x000D_
background-position:_x000D_
/* 1) Image position        */ 0 0, _x000D_
/* 2) Gradient position     */ 0 100px,_x000D_
/* 3) Color position        */ 0 130px;_x000D_
_x000D_
background-size:  _x000D_
/* 1) Image size            */ 640px 100px,_x000D_
/* 2) Gradient size         */ 100% 30px, _x000D_
/* 3) Color size            */ 100% 30px;_x000D_
}
_x000D_
_x000D_
_x000D_

How can my iphone app detect its own version number?

A succinct way to obtain a version string in X.Y.Z format is:

[NSBundle mainBundle].infoDictionary[@"CFBundleVersion"]

Or, for just X.Y:

[NSBundle mainBundle].infoDictionary[@"CFBundleShortVersionString"]

Both of these snippets returns strings that you would assign to your label object's text property, e.g.

myLabel.text = [NSBundle mainBundle].infoDictionary[@"CFBundleVersion"];

How do I add a new class to an element dynamically?

This is how you do it:

var e = document.getElementById('myIdName');
var value = window.getComputedStyle(e, null).getPropertyValue("zIndex");
alert('z-index: ' + value);

Is there an "if -then - else " statement in XPath?

Yes, there is a way to do it in XPath 1.0:

concat(
  substring($s1, 1, number($condition)      * string-length($s1)),
  substring($s2, 1, number(not($condition)) * string-length($s2))
)

This relies on the concatenation of two mutually exclusive strings, the first one being empty if the condition is false (0 * string-length(...)), the second one being empty if the condition is true. This is called "Becker's method", attributed to Oliver Becker.

In your case:

concat(
  substring(
    substring-before(//div[@id='head']/text(), ': '),
    1, 
    number(
      ends-with(//div[@id='head']/text(), ': ')
    )
    * string-length(substring-before(//div [@id='head']/text(), ': '))
  ),
  substring(
    //div[@id='head']/text(), 
    1, 
    number(not(
      ends-with(//div[@id='head']/text(), ': ')
    ))
    * string-length(//div[@id='head']/text())
  )
)

Though I would try to get rid of all the "//" before.

Also, there is the possibility that //div[@id='head'] returns more than one node.
Just be aware of that — using //div[@id='head'][1] is more defensive.

android.os.NetworkOnMainThreadException with android 4.2

Please make sure that you don't do any network access on UI Thread, instead do it in Async Task

The reason why your application crashes on Android versions 3.0 and above, but works fine on Android 2.x is because since HoneyComb are much stricter about abuse against the UI Thread. For example, when an Android device running HoneyComb or above detects a network access on the UI thread, a NetworkOnMainThreadException will be thrown.

See this

How to run travis-ci locally

Travis-ci offers a new container-based infrastructure that uses docker. This can be very useful if you're trying to troubleshoot a travis-ci build by reproducing it locally. This is taken from Travis CI's documentation.

Troubleshooting Locally in a Docker Image

If you're having trouble tracking down the exact problem in a build it often helps to run the build locally. To do this you need to be using our container based infrastructure (ie, have sudo: false in your .travis.yml), and to know which Docker image you are using on Travis CI.

Running a Container Based Docker Image Locally

  1. Download and install the Docker Engine.
  2. Select an image from Docker Hub. If you're not using a language-specific image pick ci-ruby. Open a terminal and start an interactive Docker session using the image URL:

    docker run -it travisci/ubuntu-ruby:18.04 /bin/bash
    
  3. Switch to the travis user:

    su - travis
    
  4. Clone your git repository into the / folder of the image.
  5. Manually install any dependencies.
  6. Manually run your Travis CI build command.

Delete the last two characters of the String

You may also try the following code with exception handling. Here you have a method removeLast(String s, int n) (it is actually an modified version of masud.m's answer). You have to provide the String s and how many char you want to remove from the last to this removeLast(String s, int n) function. If the number of chars have to remove from the last is greater than the given String length then it throws a StringIndexOutOfBoundException with a custom message -

public String removeLast(String s, int n) throws StringIndexOutOfBoundsException{

        int strLength = s.length();

        if(n>strLength){
            throw new StringIndexOutOfBoundsException("Number of character to remove from end is greater than the length of the string");
        }

        else if(null!=s && !s.isEmpty()){

            s = s.substring(0, s.length()-n);
        }

        return s;

    }

Scrolling a flexbox with overflowing content

I just solved this problem very elegantly after a lot of trial and error.

Check out my blog post: http://geon.github.io/programming/2016/02/24/flexbox-full-page-web-app-layout

Basically, to make a flexbox cell scrollable, you have to make all its parents overflow: hidden;, or it will just ignore your overflow settings and make the parent larger instead.

Is there a way to get a list of column names in sqlite?

You can use sqlite3 and pep-249

import sqlite3
connection = sqlite3.connect('~/foo.sqlite')
cursor = connection.execute('select * from bar')

cursor.description is description of columns

names = list(map(lambda x: x[0], cursor.description))

Alternatively you could use a list comprehension:

names = [description[0] for description in cursor.description]

How can I see the size of files and directories in linux?

you can use ls -sh in linux you can do sort also you need to go to dir where you want to check the size of files

NPM Install Error:Unexpected end of JSON input while parsing near '...nt-webpack-plugin":"0'

delete npm and npm-cache folders in C:\Users\admin\AppData\Roaming\ (windows) then execute cmd

npm cache clear --force

npm cache verify

update npm to latest version

npm i -g npm

then create your project 1)Angular

npm i -g @angular/cli@latest

ng new HelloWorld

2)React

npm i -g create-react-app

create-react-app react-app

How to export SQL Server 2005 query to CSV

If you can not use Management studio i use sqlcmd.

sqlcmd -q "select col1,col2,col3 from table" -oc:\myfile.csv -h-1 -s","

That is the fast way to do it from command line.

Use CSS to remove the space between images

An easy way that is compatible pretty much everywhere is to set font-size: 0 on the container, provided you don't have any descendent text nodes you need to style (though it is trivial to override this where needed).

.nospace {
   font-size: 0;
}

jsFiddle.

You could also change from the default display: inline into block or inline-block. Be sure to use the workarounds required for <= IE7 (and possibly ancient Firefoxes) for inline-block to work.

jquery click event not firing?

Might be useful to some : check for

pointer-events: none;

In the CSS. It prevents clicks from being caught by JS. I think it's relevant because the CSS might be the last place you'd look into in this kind of situation.

How to set 24-hours format for date on java?

Date d=new Date(new Date().getTime()+28800000);
String s=new SimpleDateFormat("dd/MM/yyyy HH:mm:ss").format(d);

HH will return 0-23 for hours.

kk will return 1-24 for hours.

See more here: Customizing Formats

use method setIs24HourView(Boolean is24HourView) to set time picker to set 24 hour view.

How to Select Every Row Where Column Value is NOT Distinct

The thing that is incorrect with your query is that you are grouping by email and name, that forms a group of each unique set of email and name combined together and hence

aaron and [email protected]
christy and [email protected]
john and [email protected]

are treated as 3 different groups rather all belonging to 1 single group.

Please use the query as given below :

select emailaddress,customername from customers where emailaddress in
(select emailaddress from customers group by emailaddress having count(*) > 1)

Enum ToString with user friendly strings

Maybe I'm missing something, but what's wrong with Enum.GetName?

public string GetName(PublishStatusses value)
{
    return Enum.GetName(typeof(PublishStatusses), value)
}

edit: for user-friendly strings, you need to go through a .resource to get internationalisation/localisation done, and it would arguably be better to use a fixed key based on the enum key than a decorator attribute on the same.

How to plot a subset of a data frame in R?

Most straightforward option:

plot(var1[var3<155],var2[var3<155])

It does not look good because of code redundancy, but is ok for fastndirty hacking.

Timeout for python requests.get entire response

this code working for socketError 11004 and 10060......

# -*- encoding:UTF-8 -*-
__author__ = 'ACE'
import requests
from PyQt4.QtCore import *
from PyQt4.QtGui import *


class TimeOutModel(QThread):
    Existed = pyqtSignal(bool)
    TimeOut = pyqtSignal()

    def __init__(self, fun, timeout=500, parent=None):
        """
        @param fun: function or lambda
        @param timeout: ms
        """
        super(TimeOutModel, self).__init__(parent)
        self.fun = fun

        self.timeer = QTimer(self)
        self.timeer.setInterval(timeout)
        self.timeer.timeout.connect(self.time_timeout)
        self.Existed.connect(self.timeer.stop)
        self.timeer.start()

        self.setTerminationEnabled(True)

    def time_timeout(self):
        self.timeer.stop()
        self.TimeOut.emit()
        self.quit()
        self.terminate()

    def run(self):
        self.fun()


bb = lambda: requests.get("http://ipv4.download.thinkbroadband.com/1GB.zip")

a = QApplication([])

z = TimeOutModel(bb, 500)
print 'timeout'

a.exec_()

Passing data between different controller action methods

HTTP and redirects

Let's first recap how ASP.NET MVC works:

  1. When an HTTP request comes in, it is matched against a set of routes. If a route matches the request, the controller action corresponding to the route will be invoked.
  2. Before invoking the action method, ASP.NET MVC performs model binding. Model binding is the process of mapping the content of the HTTP request, which is basically just text, to the strongly typed arguments of your action method

Let's also remind ourselves what a redirect is:

An HTTP redirect is a response that the webserver can send to the client, telling the client to look for the requested content under a different URL. The new URL is contained in a Location header that the webserver returns to the client. In ASP.NET MVC, you do an HTTP redirect by returning a RedirectResult from an action.

Passing data

If you were just passing simple values like strings and/or integers, you could pass them as query parameters in the URL in the Location header. This is what would happen if you used something like

return RedirectToAction("ActionName", "Controller", new { arg = updatedResultsDocument });

as others have suggested

The reason that this will not work is that the XDocument is a potentially very complex object. There is no straightforward way for the ASP.NET MVC framework to serialize the document into something that will fit in a URL and then model bind from the URL value back to your XDocument action parameter.

In general, passing the document to the client in order for the client to pass it back to the server on the next request, is a very brittle procedure: it would require all sorts of serialisation and deserialisation and all sorts of things could go wrong. If the document is large, it might also be a substantial waste of bandwidth and might severely impact the performance of your application.

Instead, what you want to do is keep the document around on the server and pass an identifier back to the client. The client then passes the identifier along with the next request and the server retrieves the document using this identifier.

Storing data for retrieval on the next request

So, the question now becomes, where does the server store the document in the meantime? Well, that is for you to decide and the best choice will depend upon your particular scenario. If this document needs to be available in the long run, you may want to store it on disk or in a database. If it contains only transient information, keeping it in the webserver's memory, in the ASP.NET cache or the Session (or TempData, which is more or less the same as the Session in the end) may be the right solution. Either way, you store the document under a key that will allow you to retrieve the document later:

int documentId = _myDocumentRepository.Save(updatedResultsDocument);

and then you return that key to the client:

return RedirectToAction("UpdateConfirmation", "ApplicationPoolController ", new { id = documentId });

When you want to retrieve the document, you simply fetch it based on the key:

 public ActionResult UpdateConfirmation(int id)
 {
      XDocument doc = _myDocumentRepository.GetById(id);

      ConfirmationModel model = new ConfirmationModel(doc);

      return View(model);
 }

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

It looks like, cargo can have one or more item. Each item would have a reference to its corresponding cargo.

From the log, item object is inserted first and then an attempt is made to update the cargo object (which does not exist).

I guess what you actually want is cargo object to be created first and then the item object to be created with the id of the cargo object as the reference - so, essentally re-look at the save() method in the Action class.

Finding the Eclipse Version Number

1 - Open Eclipse IDE. 2 - Press: Alt + H 3 - Use keyboard arrows to go dwn the list 4 - Select About Eclipse IDE tab.

Android translate animation - permanently move View to new position using AnimationListener

I usually prefer to work with deltas in translate animation, since it avoids a lot of confusion.

Try this out, see if it works for you:

TranslateAnimation anim = new TranslateAnimation(0, amountToMoveRight, 0, amountToMoveDown);
anim.setDuration(1000);

anim.setAnimationListener(new TranslateAnimation.AnimationListener() {

    @Override
    public void onAnimationStart(Animation animation) { }

    @Override
    public void onAnimationRepeat(Animation animation) { }

    @Override
    public void onAnimationEnd(Animation animation) 
    {
        FrameLayout.LayoutParams params = (FrameLayout.LayoutParams)view.getLayoutParams();
        params.topMargin += amountToMoveDown;
        params.leftMargin += amountToMoveRight;
        view.setLayoutParams(params);
    }
});

view.startAnimation(anim);

Make sure to make amountToMoveRight / amountToMoveDown final

Hope this helps :)

java.sql.SQLException: - ORA-01000: maximum open cursors exceeded

I faced the same issue because I was querying db for more than 1000 iterations. I have used try and finally in my code. But was still getting error.

To solve this I just logged into oracle db and ran below query:

ALTER SYSTEM SET open_cursors = 8000 SCOPE=BOTH;

And this solved my problem immediately.

jQuery ui datepicker with Angularjs

Unfortunately, vicont's answer did not work for me, so I searched for another solution which is as elegant and works for nested attributes in the ng-model as well. It uses $parse and accesses the ng-model through the attrs in the linking function instead of requiring it:

myApp.directive('myDatepicker', function ($parse) {
    return function (scope, element, attrs, controller) {
      var ngModel = $parse(attrs.ngModel);
      $(function(){
        element.datepicker({
            ...
            onSelect:function (dateText, inst) {
                scope.$apply(function(scope){
                    // Change binded variable
                    ngModel.assign(scope, dateText);
                });
            }
        });
     });
    } 
});

Source: ANGULAR.JS BINDING TO JQUERY UI (DATEPICKER EXAMPLE)

How to Configure SSL for Amazon S3 bucket

I found you can do this easily via the Cloud Flare service.

Set up a bucket, enable webhosting on the bucket and point the desired CNAME to that endpoint via Cloudflare... and pay for the service of course... but $5-$20 VS $600 is much easier to stomach.

Full detail here: https://www.engaging.io/easy-way-to-configure-ssl-for-amazon-s3-bucket-via-cloudflare/

How to fix C++ error: expected unqualified-id

As a side note, consider passing strings in setWord() as const references to avoid excess copying. Also, in displayWord, consider making this a const function to follow const-correctness.

void setWord(const std::string& word) {
  theWord = word;
}

Check which element has been clicked with jQuery

The basis of jQuery is the ability to find items in the DOM through selectors, and then checking properties on those selectors. Read up on Selectors here:

http://api.jquery.com/category/selectors/

However, it would make more sense to create event handlers for the click events for the different functionality that should occur based on what is clicked.

Disabling submit button until all fields have values

I refactored the chosen answer here and improved on it. The chosen answer only works assuming you have one form per page. I solved this for multiple forms on same page (in my case I have 2 modals on same page) and my solution only checks for values on required fields. My solution gracefully degrades if JavaScript is disabled and includes a slick CSS button fade transition.

See working JS fiddle example: https://jsfiddle.net/bno08c44/4/

JS

$(function(){
 function submitState(el) {

    var $form = $(el),
        $requiredInputs = $form.find('input:required'),
        $submit = $form.find('input[type="submit"]');

    $submit.attr('disabled', 'disabled');

    $requiredInputs.keyup(function () {

      $form.data('empty', 'false');

      $requiredInputs.each(function() {
        if ($(this).val() === '') {
          $form.data('empty', 'true');
        }
      });

      if ($form.data('empty') === 'true') {
        $submit.attr('disabled', 'disabled').attr('title', 'fill in all required fields');
      } else {
        $submit.removeAttr('disabled').attr('title', 'click to submit');
      }
    });
  }

  // apply to each form element individually
  submitState('#sign_up_user');
  submitState('#login_user');
});

CSS

input[type="submit"] {
  background: #5cb85c;
  color: #fff;
  transition: background 600ms;
  cursor: pointer;
}

input[type="submit"]:disabled {
  background: #555;
  cursor: not-allowed;
}

HTML

<h4>Sign Up</h4>
<form id="sign_up_user" data-empty="" action="#" method="post">
 <input type="email" name="email" placeholder="Email" required>
 <input type="password" name="password" placeholder="Password" required>
 <input type="password" name="password_confirmation" placeholder="Password Confirmation" required>
 <input type="hidden" name="secret" value="secret">
 <input type="submit" value="signup">
</form>

<h4>Login</h4>
<form id="login_user" data-empty="" action="#" method="post">
 <input type="email" name="email" placeholder="Email" required>
 <input type="password" name="password" placeholder="Password" required>
 <input type="checkbox" name="remember" value="1"> remember me
 <input type="submit" value="signup">
</form>

iOS Swift - Get the Current Local Time and Date Timestamp

First I would recommend you to store your timestamp as a NSNumber in your Firebase Database, instead of storing it as a String.

Another thing worth mentioning here, is that if you want to manipulate dates with Swift, you'd better use Date instead of NSDate, except if you're interacting with some Obj-C code in your app.

You can of course use both, but the Documentation states:

Date bridges to the NSDate class. You can use these interchangeably in code that interacts with Objective-C APIs.

Now to answer your question, I think the problem here is because of the timezone.

For example if you print(Date()), as for now, you would get:

2017-09-23 06:59:34 +0000

This is the Greenwich Mean Time (GMT).

So depending on where you are located (or where your users are located) you need to adjust the timezone before (or after, when you try to access the data for example) storing your Date:

    let now = Date()

    let formatter = DateFormatter()

    formatter.timeZone = TimeZone.current

    formatter.dateFormat = "yyyy-MM-dd HH:mm"

    let dateString = formatter.string(from: now)

Then you have your properly formatted String, reflecting the current time at your location, and you're free to do whatever you want with it :) (convert it to a Date / NSNumber, or store it directly as a String in the database..)

Is it possible to print a variable's type in standard C++?

The other answers involving RTTI (typeid) are probably what you want, as long as:

  • you can afford the memory overhead (which can be considerable with some compilers)
  • the class names your compiler returns are useful

The alternative, (similar to Greg Hewgill's answer), is to build a compile-time table of traits.

template <typename T> struct type_as_string;

// declare your Wibble type (probably with definition of Wibble)
template <>
struct type_as_string<Wibble>
{
    static const char* const value = "Wibble";
};

Be aware that if you wrap the declarations in a macro, you'll have trouble declaring names for template types taking more than one parameter (e.g. std::map), due to the comma.

To access the name of the type of a variable, all you need is

template <typename T>
const char* get_type_as_string(const T&)
{
    return type_as_string<T>::value;
}

How can I force division to be floating point? Division keeps rounding down to 0?

Add a dot (.) to indicate floating point numbers

>>> 4/3.
1.3333333333333333

How to print an exception in Python 3?

Try

try:
    print undefined_var
except Exception as e:
    print(e)

this will print the representation given by e.__str__():

"name 'undefined_var' is not defined"

you can also use:

print(repr(e))

which will include the Exception class name:

"NameError("name 'undefined_var' is not defined",)"

npm check and update package if needed

npm outdated will identify packages that should be updated, and npm update <package name> can be used to update each package. But prior to [email protected], npm update <package name> will not update the versions in your package.json which is an issue.

The best workflow is to:

  1. Identify out of date packages
  2. Update the versions in your package.json
  3. Run npm update to install the latest versions of each package

Check out npm-check-updates to help with this workflow.

  • Install npm-check-updates
  • Run npm-check-updates to list what packages are out of date (basically the same thing as running npm outdated)
  • Run npm-check-updates -u to update all the versions in your package.json (this is the magic sauce)
  • Run npm update as usual to install the new versions of your packages based on the updated package.json

Where is the list of predefined Maven properties

I think the best place to look is the Super POM.

As an example, at the time of writing, the linked reference shows some of the properties between lines 32 - 48.

The interpretation of this is to follow the XPath as a . delimited property.

So, for example:

${project.build.testOutputDirectory} == ${project.build.directory}/test-classes

And:

${project.build.directory} == ${project.basedir}/target

Thus combining them, we find:

${project.build.testOutputDirectory} == ${project.basedir}/target/test-classes

(To reference the resources directory(s), see this stackoverflow question)


<project>
    <modelVersion>4.0.0</modelVersion>
    .
    .
    .
    <build>
        <directory>${project.basedir}/target</directory>
        <outputDirectory>${project.build.directory}/classes</outputDirectory>
        <finalName>${project.artifactId}-${project.version}</finalName>
        <testOutputDirectory>${project.build.directory}/test-classes</testOutputDirectory>
        <sourceDirectory>${project.basedir}/src/main/java</sourceDirectory>
        <scriptSourceDirectory>src/main/scripts</scriptSourceDirectory>
        <testSourceDirectory>${project.basedir}/src/test/java</testSourceDirectory>
        <resources>
            <resource>
                <directory>${project.basedir}/src/main/resources</directory>
            </resource>
        </resources>
        <testResources>
            <testResource>
                <directory>${project.basedir}/src/test/resources</directory>
            </testResource>
        </testResources>
        .
        .
        .
    </build>
    .
    .
    .
</project>

Virtualhost For Wildcard Subdomain and Static Subdomain

This also works for https needed a solution to making project directories this was it. because chrome doesn't like non ssl anymore used free ssl. Notice: My Web Server is Wamp64 on Windows 10 so I wouldn't use this config because of variables unless your using wamp.

<VirtualHost *:443>
ServerAdmin [email protected]
ServerName test.com
ServerAlias *.test.com

SSLEngine On
SSLCertificateFile "conf/key/certificatecom.crt"
SSLCertificateKeyFile "conf/key/privatecom.key"

VirtualDocumentRoot "${INSTALL_DIR}/www/subdomains/%1/"

DocumentRoot "${INSTALL_DIR}/www/subdomains"
<Directory "${INSTALL_DIR}/www/subdomains/">
    Options +Indexes +Includes +FollowSymLinks +MultiViews
AllowOverride All
Require all granted
</Directory>

How to make a input field readonly with JavaScript?

document.getElementById('TextBoxID').readOnly = true;    //to enable readonly


document.getElementById('TextBoxID').readOnly = false;   //to  disable readonly

mysql update column with value from another table

The second option is feasible also if you're using safe updates mode (and you're getting an error indicating that you've tried to update a table without a WHERE that uses a KEY column), by adding:

UPDATE TableB  
SET TableB.value = (  
SELECT TableA.value  
    FROM TableA  
    WHERE TableA.name = TableB.name  
)  
**where TableB.id < X**  
;

What's the shebang/hashbang (#!) in Facebook and new Twitter URLs for?

Answers above describe well why and how it is used on twitter and facebook, what I missed is explanation what # does by default...

On a 'normal' (not a single page application) you can do anchoring with hash to any element that has id by placing that elements id in url after hash #

Example:

(on Chrome) Click F12 or Rihgt Mouse and Inspect element

enter image description here

then take id="answer-10831233" and add to url like following

https://stackoverflow.com/questions/3009380/whats-the-shebang-hashbang-in-facebook-and-new-twitter-urls-for#answer-10831233

and you will get a link that jumps to that element on the page

What's the shebang/hashbang (#!) in Facebook and new Twitter URLs for?

By using # in a way described in the answers above you are introducing conflicting behaviour... although I wouldn't loose sleep over it... since Angular it became somewhat of a standard....

How to find the highest value of a column in a data frame in R?

Here's a dplyr solution:

library(dplyr)

# find max for each column
summarise_each(ozone, funs(max(., na.rm=TRUE)))

# sort by Solar.R, descending
arrange(ozone, desc(Solar.R))

UPDATE: summarise_each() has been deprecated in favour of a more featureful family of functions: mutate_all(), mutate_at(), mutate_if(), summarise_all(), summarise_at(), summarise_if()

Here is how you could do:

# find max for each column
ozone %>%
         summarise_if(is.numeric, funs(max(., na.rm=TRUE)))%>%
         arrange(Ozone)

or

ozone %>%
         summarise_at(vars(1:6), funs(max(., na.rm=TRUE)))%>%
         arrange(Ozone)

How to persist a property of type List<String> in JPA?

It seems none of the answers explored the most important settings for a @ElementCollection mapping.

When you map a list with this annotation and let JPA/Hibernate auto-generate the tables, columns, etc., it'll use auto-generated names as well.

So, let's analyze a basic example:

@Entity
@Table(name = "sample")
public class MySample {

    @Id
    @GeneratedValue
    private Long id;

    @ElementCollection // 1
    @CollectionTable(name = "my_list", joinColumns = @JoinColumn(name = "id")) // 2
    @Column(name = "list") // 3
    private List<String> list;
    
}
  1. The basic @ElementCollection annotation (where you can define the known fetch and targetClass preferences)
  2. The @CollectionTable annotation is very useful when it comes to giving a name to the table that'll be generated, as well as definitions like joinColumns, foreignKey's, indexes, uniqueConstraints, etc.
  3. @Column is important to define the name of the column that'll store the varchar value of the list.

The generated DDL creation would be:

-- table sample
CREATE TABLE sample (
  id bigint(20) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (id)
);

-- table my_list
CREATE TABLE IF NOT EXISTS my_list (
  id bigint(20) NOT NULL,
  list varchar(255) DEFAULT NULL,
  FOREIGN KEY (id) REFERENCES sample (id)
);

What is the return value of os.system() in Python?

You might want to use

return_value = os.popen('ls').read()

instead. os.system only returns the error value.

The os.popen is a neater wrapper for subprocess.Popen function as is seen within the python source code.

XPath using starts-with function

Use:

//REVENUE_YEAR[starts-with(.,'2552')]/../REGION/text() 

What are best practices for REST nested resources?

What you have done is correct. In general there can be many URIs to the same resource - there are no rules that say you shouldn't do that.

And generally, you may need to access items directly or as a subset of something else - so your structure makes sense to me.

Just because employees are accessible under department:

company/{companyid}/department/{departmentid}/employees

Doesn't mean they can't be accessible under company too:

company/{companyid}/employees

Which would return employees for that company. It depends on what is needed by your consuming client - that is what you should be designing for.

But I would hope that all URLs handlers use the same backing code to satisfy the requests so that you aren't duplicating code.

Reliable method to get machine's MAC address in C#

Try this:

    /// <summary>
    /// returns the first MAC address from where is executed 
    /// </summary>
    /// <param name="flagUpOnly">if sets returns only the nic on Up status</param>
    /// <returns></returns>
    public static string[] getOperationalMacAddresses(Boolean flagUpOnly)
    {
        string[] macAddresses = new string[NetworkInterface.GetAllNetworkInterfaces().Count()];

        int i = 0;
        foreach (NetworkInterface nic in NetworkInterface.GetAllNetworkInterfaces())
        {
            if (nic.OperationalStatus == OperationalStatus.Up || !flagUpOnly)
            {
                macAddresses[i] += ByteToHex(nic.GetPhysicalAddress().GetAddressBytes());
                //break;
                i++;
            }
        }
        return macAddresses;
    }

Array of char* should end at '\0' or "\0"?

Null termination is a bad design pattern best left in the history books. There's still plenty of inertia behind c-strings, so it can't be avoided there. But there's no reason to use it in the OP's example.

Don't use any terminator, and use sizeof(array) / sizeof(array[0]) to get the number of elements.

Bash scripting missing ']'

add a space before the close bracket

What's the difference between utf8_general_ci and utf8_unicode_ci?

There are two big difference the sorting and the character matching:

Sorting:

  • utf8mb4_general_ci removes all accents and sorts one by one which may create incorrect sort results.
  • utf8mb4_unicode_ci sorts accurate.

Character Matching

They match characters differently.

For example, in utf8mb4_unicode_ci you have i != i, but in utf8mb4_general_ci it holds i=i.

For example, imagine you have a row with name="Yilmaz". Then

select id from users where name='Yilmaz';

would return the row if collocation is utf8mb4_general_ci, but if it is collocated with utf8mb4_unicode_ci it would not return the row!

On the other hand we have that a=ª and ß=ss in utf8mb4_unicode_ci which is not the case in utf8mb4_general_ci. So imagine you have a row with name="ªßi", then

select id from users where name='assi';

would return the row if collocation is utf8mb4_unicode_ci, but would not return a row if collocation is set to utf8mb4_general_ci.

A full list of matches for each collocation may be found here.

Why is "cursor:pointer" effect in CSS not working

I have the same issue, when I close the chrome window popup browser inspector its working fine for me.

Professional jQuery based Combobox control?

If you don't need multi-column, chosen is another good choice. MIT Licensed

Can't perform a React state update on an unmounted component

Depending on how you open your webpage, you may not be causing a mounting. Such as using a <Link/> back to a page that was already mounted in the virtual DOM, so requiring data from a componentDidMount lifecycle is caught.

Get Absolute Position of element within the window in wpf

Hm. You have to specify window you clicked in Mouse.GetPosition(IInputElement relativeTo) Following code works well for me

protected override void OnMouseDown(MouseButtonEventArgs e)
    {
        base.OnMouseDown(e);
        Point p = e.GetPosition(this);
    }

I suspect that you need to refer to the window not from it own class but from other point of the application. In this case Application.Current.MainWindow will help you.

ArrayList insertion and retrieval order

Yes, ArrayList is an ordered collection and it maintains the insertion order.

Check the code below and run it:

public class ListExample {

    public static void main(String[] args) {
        List<String> myList = new ArrayList<String>();
        myList.add("one");
        myList.add("two");
        myList.add("three");
        myList.add("four");
        myList.add("five");
    
        System.out.println("Inserted in 'order': ");
        printList(myList);
        System.out.println("\n");
        System.out.println("Inserted out of 'order': ");

        // Clear the list
        myList.clear();
    
        myList.add("four");
        myList.add("five");
        myList.add("one");
        myList.add("two");
        myList.add("three");
    
        printList(myList);
    }

    private static void printList(List<String> myList) {
        for (String string : myList) {
            System.out.println(string);
        }
    }
}

Produces the following output:

Inserted in 'order': 
one
two
three
four
five


Inserted out of 'order': 
four
five
one
two
three

For detailed information, please refer to documentation: List (Java Platform SE7)

Git keeps asking me for my ssh key passphrase

Another possible solution that is not mentioned above is to check your remote with the following command:

git remote -v

If the remote does not start with git but starts with https you might want to change it to git by following the example below.

git remote -v // origin is https://github.com/user/myrepo.git
git remote set-url origin [email protected]:user/myrepo.git
git remote -v // check if remote is changed

How to launch jQuery Fancybox on page load?

Window.load (as opposed to document.ready()) appears to the be the trick used in the JSFiddler onload demos of Fancybox 2.0:

$(window).load(function()
{
    $.fancybox("test");
});

Bare in mind you may be using document.ready() elsewhere, and IE9 gets upset with the load order of the two. This leaves you with two options: change everything to window.load or use a setTimer().

The specified child already has a parent. You must call removeView() on the child's parent first (Android)

if(tv!= null){
    ((ViewGroup)tv.getParent()).removeView(tv); // <- fix
}

Why is 1/1/1970 the "epoch time"?

http://en.wikipedia.org/wiki/Unix_time#History explains a little about the origins of Unix time and the chosen epoch. The definition of unix time and the epoch date went through a couple of changes before stabilizing on what it is now.

But it does not say why exactly 1/1/1970 was chosen in the end.

Notable excerpts from the Wikipedia page:

The first edition Unix Programmer's Manual dated November 3, 1971 defines the Unix time as "the time since 00:00:00, Jan. 1, 1971, measured in sixtieths of a second".

Because of [the] limited range, the epoch was redefined more than once, before the rate was changed to 1 Hz and the epoch was set to its present value.

Several later problems, including the complexity of the present definition, result from Unix time having been defined gradually by usage rather than fully defined to start with.

Numpy AttributeError: 'float' object has no attribute 'exp'

Probably there's something wrong with the input values for X and/or T. The function from the question works ok:

import numpy as np
from math import e

def sigmoid(X, T):
  return 1.0 / (1.0 + np.exp(-1.0 * np.dot(X, T)))

X = np.array([[1, 2, 3], [5, 0, 0]])
T = np.array([[1, 2], [1, 1], [4, 4]])

print(X.dot(T))
# Just to see if values are ok
print([1. / (1. + e ** el) for el in [-5, -10, -15, -16]])
print()
print(sigmoid(X, T))

Result:

[[15 16]
 [ 5 10]]

[0.9933071490757153, 0.9999546021312976, 0.999999694097773, 0.9999998874648379]

[[ 0.99999969  0.99999989]
 [ 0.99330715  0.9999546 ]]

Probably it's the dtype of your input arrays. Changing X to:

X = np.array([[1, 2, 3], [5, 0, 0]], dtype=object)

Gives:

Traceback (most recent call last):
  File "/[...]/stackoverflow_sigmoid.py", line 24, in <module>
    print sigmoid(X, T)
  File "/[...]/stackoverflow_sigmoid.py", line 14, in sigmoid
    return 1.0 / (1.0 + np.exp(-1.0 * np.dot(X, T)))
AttributeError: exp

Remove ALL styling/formatting from hyperlinks

You can simply define a style for links, which would override a:hover, a:visited etc.:

a {
  color: blue;
  text-decoration: none; /* no underline */
}

You can also use the inherit value if you want to use attributes from parent styles instead:

body {
  color: blue;
}
a {
  color: inherit; /* blue colors for links too */
  text-decoration: inherit; /* no underline */
}

Remove querystring from URL

If you're into RegEx....

var newURL = testURL.match(new RegExp("[^?]+"))

How to recursively download a folder via FTP on Linux

If you can use scp instead of ftp, the -r option will do this for you. I would check to see whether you can use a more modern file transfer mechanism than FTP.

Creating a jQuery object from a big HTML-string

I use the following for my HTML templates:

$(".main").empty();

var _template = '<p id="myelement">Your HTML Code</p>';
var template = $.parseHTML(_template);
var final = $(template).find("#myelement");

$(".main").append(final.html());

Note: Assuming if you are using jQuery

Strange problem with Subversion - "File already exists" when trying to recreate a directory that USED to be in my repository

I managed to work around it by reverting back to the last version that I had the mysql directory in, then deleting the contents of the directory, putting the new contents in it, and checking the new information back in. Although I'm curious if anyone has a better explanation for what the heck was going on there.

Size-limited queue that holds last N elements in Java

Apache commons collections 4 has a CircularFifoQueue<> which is what you are looking for. Quoting the javadoc:

CircularFifoQueue is a first-in first-out queue with a fixed size that replaces its oldest element if full.

    import java.util.Queue;
    import org.apache.commons.collections4.queue.CircularFifoQueue;

    Queue<Integer> fifo = new CircularFifoQueue<Integer>(2);
    fifo.add(1);
    fifo.add(2);
    fifo.add(3);
    System.out.println(fifo);

    // Observe the result: 
    // [2, 3]

If you are using an older version of the Apache commons collections (3.x), you can use the CircularFifoBuffer which is basically the same thing without generics.

Update: updated answer following release of commons collections version 4 that supports generics.

How to get the size of a string in Python?

If you are talking about the length of the string, you can use len():

>>> s = 'please answer my question'
>>> len(s)  # number of characters in s
25

If you need the size of the string in bytes, you need sys.getsizeof():

>>> import sys
>>> sys.getsizeof(s)
58

Also, don't call your string variable str. It shadows the built-in str() function.

MessageBodyWriter not found for media type=application/json

In my experience this error is pretty common, for some reason jersey sometimes has problems parsing custom java types. Usually all you have to do is make sure that you respect the following 3 conditions:

  1. you have jersey-media-json-jackson in you pom.xml if using maven or added to your build path;
  2. you have an empty constructor in the data type you are trying to de-/serialize;
  3. you have the relevant annotation at the class and field level for your custom data type (xmlelement and/or jsonproperty);

However, I have ran into cases where this just was not enough. Then you can always wrap you custom data type in a GenericEntity and pass it as such to your ResponseBuilder:

GenericEntity<CustomDataType> entity = new GenericEntity<CustomDataType>(myObj) {};
return Response.status(httpCode).entity(entity).build();

This way you are trying to help jersey to find the proper/relevant serialization provider for you object. Well, sometimes this also is not enough. In my case I was trying to produce a text/plain from a custom data type. Theoretically jersey should have used the StringMessageProvider, but for some reason that I did not manage to discover it was giving me this error:

org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyWriter not found for media type=text/plain

So what solved the problem for me was to do my own serialization with jackson's writeValueAsString(). I'm not proud of it but at the end of the day I can deliver an acceptable solution.

Why maven? What are the benefits?

This should have been a comment, but it wasn't fitting in a comment length, so I posted it as an answer.

All the benefits mentioned in other answers are achievable by simpler means than using maven. If, for-example, you are new to a project, you'll anyway spend more time creating project architecture, joining components, coding than downloading jars and copying them to lib folder. If you are experienced in your domain, then you already know how to start off the project with what libraries. I don't see any benefit of using maven, especially when it poses a lot of problems while automatically doing the "dependency management".

I only have intermediate level knowledge of maven, but I tell you, I have done large projects(like ERPs) without using maven.

How to update record using Entity Framework 6?

So you have an entity that is updated, and you want to update it in the database with the least amount of code...

Concurrency is always tricky, but I am assuming that you just want your updates to win. Here is how I did it for my same case and modified the names to mimic your classes. In other words, just change attach to add, and it works for me:

public static void SaveBook(Model.Book myBook)
{
    using (var ctx = new BookDBContext())
    {
        ctx.Books.Add(myBook);
        ctx.Entry(myBook).State = System.Data.Entity.EntityState.Modified;
        ctx.SaveChanges();
    }
}

How to get the EXIF data from a file using C#

The command line tool ExifTool by Phil Harvey works with dozens of images formats - including plenty of proprietary RAW formats - and can manipulate a variety of metadata formats including EXIF, GPS, IPTC, XMP, JFIF.

Very easy to use, lightweight, impressive application.

How to get rid of `deprecated conversion from string constant to ‘char*’` warnings in GCC?

If it's an active code base, you might still want to upgrade the code base. Of course, performing the changes manually isn't feasible but I believe that this problem could be solved once and for all by one single sed command. I haven't tried it, though, so take the following with a grain of salt.

find . -exec sed -E -i .backup -n \
    -e 's/char\s*\*\s*(\w+)\s*= "/char const* \1 = "/g' {} \;

This might not find all places (even not considering function calls) but it would alleviate the problem and make it possible to perform the few remaining changes manually.

Java HTTPS client certificate authentication

Finally managed to solve all the issues, so I'll answer my own question. These are the settings/files I've used to manage to get my particular problem(s) solved;

The client's keystore is a PKCS#12 format file containing

  1. The client's public certificate (in this instance signed by a self-signed CA)
  2. The client's private key

To generate it I used OpenSSL's pkcs12 command, for example;

openssl pkcs12 -export -in client.crt -inkey client.key -out client.p12 -name "Whatever"

Tip: make sure you get the latest OpenSSL, not version 0.9.8h because that seems to suffer from a bug which doesn't allow you to properly generate PKCS#12 files.

This PKCS#12 file will be used by the Java client to present the client certificate to the server when the server has explicitly requested the client to authenticate. See the Wikipedia article on TLS for an overview of how the protocol for client certificate authentication actually works (also explains why we need the client's private key here).

The client's truststore is a straight forward JKS format file containing the root or intermediate CA certificates. These CA certificates will determine which endpoints you will be allowed to communicate with, in this case it will allow your client to connect to whichever server presents a certificate which was signed by one of the truststore's CA's.

To generate it you can use the standard Java keytool, for example;

keytool -genkey -dname "cn=CLIENT" -alias truststorekey -keyalg RSA -keystore ./client-truststore.jks -keypass whatever -storepass whatever
keytool -import -keystore ./client-truststore.jks -file myca.crt -alias myca

Using this truststore, your client will try to do a complete SSL handshake with all servers who present a certificate signed by the CA identified by myca.crt.

The files above are strictly for the client only. When you want to set-up a server as well, the server needs its own key- and truststore files. A great walk-through for setting up a fully working example for both a Java client and server (using Tomcat) can be found on this website.

Issues/Remarks/Tips

  1. Client certificate authentication can only be enforced by the server.
  2. (Important!) When the server requests a client certificate (as part of the TLS handshake), it will also provide a list of trusted CA's as part of the certificate request. When the client certificate you wish to present for authentication is not signed by one of these CA's, it won't be presented at all (in my opinion, this is weird behaviour, but I'm sure there's a reason for it). This was the main cause of my issues, as the other party had not configured their server properly to accept my self-signed client certificate and we assumed that the problem was at my end for not properly providing the client certificate in the request.
  3. Get Wireshark. It has great SSL/HTTPS packet analysis and will be a tremendous help debugging and finding the problem. It's similar to -Djavax.net.debug=ssl but is more structured and (arguably) easier to interpret if you're uncomfortable with the Java SSL debug output.
  4. It's perfectly possible to use the Apache httpclient library. If you want to use httpclient, just replace the destination URL with the HTTPS equivalent and add the following JVM arguments (which are the same for any other client, regardless of the library you want to use to send/receive data over HTTP/HTTPS):

    -Djavax.net.debug=ssl
    -Djavax.net.ssl.keyStoreType=pkcs12
    -Djavax.net.ssl.keyStore=client.p12
    -Djavax.net.ssl.keyStorePassword=whatever
    -Djavax.net.ssl.trustStoreType=jks
    -Djavax.net.ssl.trustStore=client-truststore.jks
    -Djavax.net.ssl.trustStorePassword=whatever

Rotating a Vector in 3D Space

If you want to rotate a vector you should construct what is known as a rotation matrix.

Rotation in 2D

Say you want to rotate a vector or a point by ?, then trigonometry states that the new coordinates are

    x' = x cos ? - y sin ?
    y' = x sin ? + y cos ?

To demo this, let's take the cardinal axes X and Y; when we rotate the X-axis 90° counter-clockwise, we should end up with the X-axis transformed into Y-axis. Consider

    Unit vector along X axis = <1, 0>
    x' = 1 cos 90 - 0 sin 90 = 0
    y' = 1 sin 90 + 0 cos 90 = 1
    New coordinates of the vector, <x', y'> = <0, 1>  ?  Y-axis

When you understand this, creating a matrix to do this becomes simple. A matrix is just a mathematical tool to perform this in a comfortable, generalized manner so that various transformations like rotation, scale and translation (moving) can be combined and performed in a single step, using one common method. From linear algebra, to rotate a point or vector in 2D, the matrix to be built is

    |cos ?   -sin ?| |x| = |x cos ? - y sin ?| = |x'|
    |sin ?    cos ?| |y|   |x sin ? + y cos ?|   |y'|

Rotation in 3D

That works in 2D, while in 3D we need to take in to account the third axis. Rotating a vector around the origin (a point) in 2D simply means rotating it around the Z-axis (a line) in 3D; since we're rotating around Z-axis, its coordinate should be kept constant i.e. 0° (rotation happens on the XY plane in 3D). In 3D rotating around the Z-axis would be

    |cos ?   -sin ?   0| |x|   |x cos ? - y sin ?|   |x'|
    |sin ?    cos ?   0| |y| = |x sin ? + y cos ?| = |y'|
    |  0       0      1| |z|   |        z        |   |z'|

around the Y-axis would be

    | cos ?    0   sin ?| |x|   | x cos ? + z sin ?|   |x'|
    |   0      1       0| |y| = |         y        | = |y'|
    |-sin ?    0   cos ?| |z|   |-x sin ? + z cos ?|   |z'|

around the X-axis would be

    |1     0           0| |x|   |        x        |   |x'|
    |0   cos ?    -sin ?| |y| = |y cos ? - z sin ?| = |y'|
    |0   sin ?     cos ?| |z|   |y sin ? + z cos ?|   |z'|

Note 1: axis around which rotation is done has no sine or cosine elements in the matrix.

Note 2: This method of performing rotations follows the Euler angle rotation system, which is simple to teach and easy to grasp. This works perfectly fine for 2D and for simple 3D cases; but when rotation needs to be performed around all three axes at the same time then Euler angles may not be sufficient due to an inherent deficiency in this system which manifests itself as Gimbal lock. People resort to Quaternions in such situations, which is more advanced than this but doesn't suffer from Gimbal locks when used correctly.

I hope this clarifies basic rotation.

Rotation not Revolution

The aforementioned matrices rotate an object at a distance r = v(x² + y²) from the origin along a circle of radius r; lookup polar coordinates to know why. This rotation will be with respect to the world space origin a.k.a revolution. Usually we need to rotate an object around its own frame/pivot and not around the world's i.e. local origin. This can also be seen as a special case where r = 0. Since not all objects are at the world origin, simply rotating using these matrices will not give the desired result of rotating around the object's own frame. You'd first translate (move) the object to world origin (so that the object's origin would align with the world's, thereby making r = 0), perform the rotation with one (or more) of these matrices and then translate it back again to its previous location. The order in which the transforms are applied matters. Combining multiple transforms together is called concatenation or composition.

Composition

I urge you to read about linear and affine transformations and their composition to perform multiple transformations in one shot, before playing with transformations in code. Without understanding the basic maths behind it, debugging transformations would be a nightmare. I found this lecture video to be a very good resource. Another resource is this tutorial on transformations that aims to be intuitive and illustrates the ideas with animation (caveat: authored by me!).

Rotation around Arbitrary Vector

A product of the aforementioned matrices should be enough if you only need rotations around cardinal axes (X, Y or Z) like in the question posted. However, in many situations you might want to rotate around an arbitrary axis/vector. The Rodrigues' formula (a.k.a. axis-angle formula) is a commonly prescribed solution to this problem. However, resort to it only if you’re stuck with just vectors and matrices. If you're using Quaternions, just build a quaternion with the required vector and angle. Quaternions are a superior alternative for storing and manipulating 3D rotations; it's compact and fast e.g. concatenating two rotations in axis-angle representation is fairly expensive, moderate with matrices but cheap in quaternions. Usually all rotation manipulations are done with quaternions and as the last step converted to matrices when uploading to the rendering pipeline. See Understanding Quaternions for a decent primer on quaternions.

Java Serializable Object to Byte Array

In case you want a nice no dependencies copy-paste solution. Grab the code below.

Example

MyObject myObject = ...

byte[] bytes = SerializeUtils.serialize(myObject);
myObject = SerializeUtils.deserialize(bytes);

Source

import java.io.*;

public class SerializeUtils {

    public static byte[] serialize(Serializable value) throws IOException {
        ByteArrayOutputStream out = new ByteArrayOutputStream();

        try(ObjectOutputStream outputStream = new ObjectOutputStream(out)) {
            outputStream.writeObject(value);
        }

        return out.toByteArray();
    }

    public static <T extends Serializable> T deserialize(byte[] data) throws IOException, ClassNotFoundException {
        try(ByteArrayInputStream bis = new ByteArrayInputStream(data)) {
            //noinspection unchecked
            return (T) new ObjectInputStream(bis).readObject();
        }
    }
}

mysql said: Cannot connect: invalid settings. xampp

Put generated password in config.inc.php if you changed root user password. I was repeatedly putting password that it asks in phpmyadmin and not generated password.

Being a noob in php and just starting out in xampp, I changed root user password and phpmyadmin has generate password button which generates password that's suppose to get updated in config.inc.php files line but it didn't so I manually updated it.

$cfg['Servers'][$i]['password'] = 'dRHfGtwfJXhzC96M'; 

On the other hand, this might also help, it involves adding a line to resetroot.bat

Get a list of checked checkboxes in a div using jQuery

Would this do?

var selected = [];
$('div#checkboxes input[type=checkbox]').each(function() {
   if ($(this).is(":checked")) {
       selected.push($(this).attr('name'));
   }
});

GlobalConfiguration.Configure() not present after Web API 2 and .NET 4.5.1 migration

GlobalConfiguration.Configure API is available in "Microsoft.AspNet.WebApi.WebHost" version="5.2.3"

and not in "Microsoft.AspNet.WebApi.WebHost" version="4.0.0"

Put icon inside input element in a form

I didn't want to change the background of my input text neither it will work with my SVG icon.

What i did is adding negative margin to the icon so it appear inside the input box

and adding same value padding to the input so text won't go under the icon.

<div class="search-input-container">

  <input
    type="text"
    class="search-input"
    style="padding-right : 30px;"
  />

  <img 
    src="@/assets/search-icon.svg" 
    style="margin-left: -30px;"
   />

</div>

*inline-style is for readability consider using classes

How to send a pdf file directly to the printer using JavaScript?

a function to house the print trigger...

function printTrigger(elementId) {
    var getMyFrame = document.getElementById(elementId);
    getMyFrame.focus();
    getMyFrame.contentWindow.print();
}

an button to give the user access...

(an onClick on an a or button or input or whatever you wish)

<input type="button" value="Print" onclick="printTrigger('iFramePdf');" />
an iframe pointing to your PDF...

<iframe id="iFramePdf" src="myPdfUrl.pdf" style="dispaly:none;"></iframe>

More : http://www.fpdf.org/en/script/script36.php

How to generate a unique hash code for string input in android...?

String input = "some input string";
int hashCode = input.hashCode();
System.out.println("input hash code = " + hashCode);

Go to first line in a file in vim?

If you are using gvim, you could just hit Ctrl + Home to go the first line. Similarly, Ctrl + End goes to the last line.

Can I add and remove elements of enumeration at runtime in Java

I faced this problem on the formative project of my young career.

The approach I took was to save the values and the names of the enumeration externally, and the end goal was to be able to write code that looked as close to a language enum as possible.

I wanted my solution to look like this:

enum HatType
{
    BASEBALL,
    BRIMLESS,
    INDIANA_JONES
}

HatType mine = HatType.BASEBALL;

// prints "BASEBALL"
System.out.println(mine.toString());

// prints true
System.out.println(mine.equals(HatType.BASEBALL));

And I ended up with something like this:

// in a file somewhere:
// 1 --> BASEBALL
// 2 --> BRIMLESS
// 3 --> INDIANA_JONES

HatDynamicEnum hats = HatEnumRepository.retrieve();

HatEnumValue mine = hats.valueOf("BASEBALL");

// prints "BASEBALL"
System.out.println(mine.toString());

// prints true
System.out.println(mine.equals(hats.valueOf("BASEBALL"));

Since my requirements were that it had to be possible to add members to the enum at run-time, I also implemented that functionality:

hats.addEnum("BATTING_PRACTICE");

HatEnumRepository.storeEnum(hats);

hats = HatEnumRepository.retrieve();

HatEnumValue justArrived = hats.valueOf("BATTING_PRACTICE");
// file now reads:
// 1 --> BASEBALL
// 2 --> BRIMLESS
// 3 --> INDIANA_JONES
// 4 --> BATTING_PRACTICE

I dubbed it the Dynamic Enumeration "pattern", and you read about the original design and its revised edition.

The difference between the two is that the revised edition was designed after I really started to grok OO and DDD. The first one I designed when I was still writing nominally procedural DDD, under time pressure no less.

Permanently Set Postgresql Schema Path

You can set the default search_path at the database level:

ALTER DATABASE <database_name> SET search_path TO schema1,schema2;

Or at the user or role level:

ALTER ROLE <role_name> SET search_path TO schema1,schema2;

Or if you have a common default schema in all your databases you could set the system-wide default in the config file with the search_path option.

When a database is created it is created by default from a hidden "template" database named template1, you could alter that database to specify a new default search path for all databases created in the future. You could also create another template database and use CREATE DATABASE <database_name> TEMPLATE <template_name> to create your databases.

Resize height with Highcharts

I had a similar problem with height except my chart was inside a bootstrap modal popup, which I'm already controlling the size of with css. However, for some reason when the window was resized horizontally the height of the chart container would expand indefinitely. If you were to drag the window back and forth it would expand vertically indefinitely. I also don't like hard-coded height/width solutions.

So, if you're doing this in a modal, combine this solution with a window resize event.

// from link
$('#ChartModal').on('show.bs.modal', function() {
    $('.chart-container').css('visibility', 'hidden');
});

$('#ChartModal').on('shown.bs.modal.', function() {
    $('.chart-container').css('visibility', 'initial');
    $('#chartbox').highcharts().reflow()
    //added
    ratio = $('.chart-container').width() / $('.chart-container').height();
});

Where "ratio" becomes a height/width aspect ratio, that will you resize when the bootstrap modal resizes. This measurement is only taken when he modal is opened. I'm storing ratio as a global but that's probably not best practice.

$(window).on('resize', function() {
    //chart-container is only visible when the modal is visible.
    if ( $('.chart-container').is(':visible') ) {
        $('#chartbox').highcharts().setSize( 
            $('.chart-container').width(),
            ($('.chart-container').width() / ratio),
            doAnimation = true );
    }       
});

So with this, you can drag your screen to the side (resizing it) and your chart will maintain its aspect ratio.

Widescreen

enter image description here

vs smaller

enter image description here

(still fiddling around with vw units, so everything in the back is too small to read lol!)

Round integers to the nearest 10

About the round(..) function returning a float

That float (double-precision in Python) is always a perfect representation of an integer, as long as it's in the range [-253..253]. (Pedants pay attention: it's not two's complement in doubles, so the range is symmetric about zero.)

See the discussion here for details.

Thread Safe C# Singleton Pattern

Another version of Singleton where the following line of code creates the Singleton instance at the time of application startup.

private static readonly Singleton singleInstance = new Singleton();

Here CLR (Common Language Runtime) will take care of object initialization and thread safety. That means we will not require to write any code explicitly for handling the thread safety for a multithreaded environment.

"The Eager loading in singleton design pattern is nothing a process in which we need to initialize the singleton object at the time of application start-up rather than on demand and keep it ready in memory to be used in future."

public sealed class Singleton
    {
        private static int counter = 0;
        private Singleton()
        {
            counter++;
            Console.WriteLine("Counter Value " + counter.ToString());
        }
        private static readonly Singleton singleInstance = new Singleton(); 

        public static Singleton GetInstance
        {
            get
            {
                return singleInstance;
            }
        }
        public void PrintDetails(string message)
        {
            Console.WriteLine(message);
        }
    }

from main :

static void Main(string[] args)
        {
            Parallel.Invoke(
                () => PrintTeacherDetails(),
                () => PrintStudentdetails()
                );
            Console.ReadLine();
        }
        private static void PrintTeacherDetails()
        {
            Singleton fromTeacher = Singleton.GetInstance;
            fromTeacher.PrintDetails("From Teacher");
        }
        private static void PrintStudentdetails()
        {
            Singleton fromStudent = Singleton.GetInstance;
            fromStudent.PrintDetails("From Student");
        }

Find unique rows in numpy.array

I've compared the suggested alternative for speed and found that, surprisingly, the void view unique solution is even a bit faster than numpy's native unique with the axis argument. If you're looking for speed, you'll want

numpy.unique(
    a.view(numpy.dtype((numpy.void, a.dtype.itemsize*a.shape[1])))
).view(a.dtype).reshape(-1, a.shape[1])

There is a bug report on GitHub for this, too.

enter image description here


Code to reproduce the plot:

import numpy
import perfplot


def unique_void_view(a):
    return (
        numpy.unique(a.view(numpy.dtype((numpy.void, a.dtype.itemsize * a.shape[1]))))
        .view(a.dtype)
        .reshape(-1, a.shape[1])
    )


def lexsort(a):
    ind = numpy.lexsort(a.T)
    return a[
        ind[numpy.concatenate(([True], numpy.any(a[ind[1:]] != a[ind[:-1]], axis=1)))]
    ]


def vstack(a):
    return numpy.vstack([tuple(row) for row in a])


def unique_axis(a):
    return numpy.unique(a, axis=0)


perfplot.show(
    setup=lambda n: numpy.random.randint(2, size=(n, 20)),
    kernels=[unique_void_view, lexsort, vstack, unique_axis],
    n_range=[2 ** k for k in range(15)],
    xlabel="len(a)",
    equality_check=None,
)

Property 'catch' does not exist on type 'Observable<any>'

With RxJS 5.5+, the catch operator is now deprecated. You should now use the catchError operator in conjunction with pipe.

RxJS v5.5.2 is the default dependency version for Angular 5.

For each RxJS Operator you import, including catchError you should now import from 'rxjs/operators' and use the pipe operator.

Example of catching error for an Http request Observable

import { Observable } from 'rxjs';
import { catchError } from 'rxjs/operators';
...

export class ExampleClass {
  constructor(private http: HttpClient) {
    this.http.request(method, url, options).pipe(
      catchError((err: HttpErrorResponse) => {
        ...
      }
    )
  }
  ...
}

Notice here that catch is replaced with catchError and the pipe operator is used to compose the operators in similar manner to what you're used to with dot-chaining.


See the rxjs documentation on pipable (previously known as lettable) operators for more info.

SSL "Peer Not Authenticated" error with HttpClient 4.1

keytool -import -v -alias cacerts -keystore cacerts.jks -storepass changeit -file C:\cacerts.cer

Filtering DataSet

No mention of Merge?

DataSet newdataset = new DataSet();

newdataset.Merge( olddataset.Tables[0].Select( filterstring, sortstring ));

How do I exit a WPF application programmatically?

To exit your application you can call

System.Windows.Application.Current.Shutdown();

As described in the documentation to the Application.Shutdown method you can also modify the shutdown behavior of your application by specifying a ShutdownMode:

Shutdown is implicitly called by Windows Presentation Foundation (WPF) in the following situations:

  • When ShutdownMode is set to OnLastWindowClose.
  • When the ShutdownMode is set to OnMainWindowClose.
  • When a user ends a session and the SessionEnding event is either unhandled, or handled without cancellation.

Please also note that Application.Current.Shutdown(); may only be called from the thread that created the Application object, i.e. normally the main thread.

How to obtain the last index of a list?

I guess you want

last_index = len(list1) - 1 

which would store 3 in last_index.

How do you determine the ideal buffer size when using FileInputStream?

You could use the BufferedStreams/readers and then use their buffer sizes.

I believe the BufferedXStreams are using 8192 as the buffer size, but like Ovidiu said, you should probably run a test on a whole bunch of options. Its really going to depend on the filesystem and disk configurations as to what the best sizes are.

Asp.NET Web API - 405 - HTTP verb used to access this page is not allowed - how to set handler mappings

If none of the above solutions solved your issue like in my case (still stuck with my RestClient module facing 405 ) try to request your Api with a tool like Postman or Fiddler. I mean the problem may be elsewhere like a bad formatted request.

I discover that my RestClient module was asking a 'Put' with an Id paremeter not well formatted :

http://myserver/api/someresource?id=75fd954d-d984-4a31-82fc-8132e1644f78

instead of

http://myserver/api/someresource/75fd954d-d984-4a31-82fc-8132e1644f78

Incidiously, bad formatted request returns 405 - Method Not Allowed (IIS 7.5)

How to create a file in memory for user to download, but not through server?

This below function worked.

 private createDownloadableCsvFile(fileName, content) {
   let link = document.createElement("a");
   link.download = fileName;
   link.href = `data:application/octet-stream,${content}`;
   return link;
 }

How to increase MaximumErrorCount in SQL Server 2008 Jobs or Packages?

It is important to highlight that the Property (MaximumErrorCount) that needs to be changed must be set as more than 0 (which is the default) in the Package level and not in the specific control that is showing the error (I tried this and it does not work!)

Be sure that in the Properties Window, the Pull down menu is set to "Package", then look for the property MaximumErrorCount to change it.

Is it necessary to assign a string to a variable before comparing it to another?

if ([statusString isEqualToString:@"Wrong"]) {
    // do something
}

C++ array initialization

You can declare the array in C++ in these type of ways. If you know the array size then you should declare the array for: integer: int myArray[array_size]; Double: double myArray[array_size]; Char and string : char myStringArray[array_size]; The difference between char and string is as follows

char myCharArray[6]={'a','b','c','d','e','f'};
char myStringArray[6]="abcdef";

If you don't know the size of array then you should leave the array blank like following.

integer: int myArray[array_size];

Double: double myArray[array_size];

How to download file from database/folder using php

here is the code to download file with how much % it is downloaded

<?php
$ch = curl_init();
$downloadFile = fopen( 'file name here', 'w' );
curl_setopt($ch, CURLOPT_URL, "file link here");
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_BUFFERSIZE, 65536);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_PROGRESSFUNCTION, 'downloadProgress'); 
curl_setopt($ch, CURLOPT_NOPROGRESS, false);
curl_setopt( $ch, CURLOPT_FILE, $downloadFile );
curl_exec($ch);
curl_close($ch);

function downloadProgress ($resource, $download_size, $downloaded_size, $upload_size, $uploaded_size) {

    if($download_size!=0){
    $percen= (($downloaded_size/$download_size)*100);
    echo $percen."<br>";

}

}
?>

Apple Mach-O Linker Error when compiling for device

I simply had to files with a main() method and Xcode wasn't happy about that.

Responsive Google Map?

in the iframe tag, you can easily add width='100%' instead of the preset value giving to you by the map

like this:

 <iframe src="https://www.google.com/maps/embed?anyLocation" width="100%" height="400" frameborder="0" style="border:0;" allowfullscreen=""></iframe>

Objective-C and Swift URL encoding

int strLength = 0;
NSString *urlStr = @"http://www";
NSLog(@" urlStr : %@", urlStr );
NSMutableString *mutableUrlStr = [urlStr mutableCopy];
NSLog(@" mutableUrlStr : %@", mutableUrlStr );
strLength = [mutableUrlStr length];
[mutableUrlStr replaceOccurrencesOfString:@":" withString:@"%3A" options:NSCaseInsensitiveSearch range:NSMakeRange(0, strLength)];
NSLog(@" mutableUrlStr : %@", mutableUrlStr );
strLength = [mutableUrlStr length];
[mutableUrlStr replaceOccurrencesOfString:@"/" withString:@"%2F" options:NSCaseInsensitiveSearch range:NSMakeRange(0, strLength)];
NSLog(@" mutableUrlStr : %@", mutableUrlStr );

Remove the last line from a file in Bash

I had trouble with all the answers here because I was working with a HUGE file (~300Gb) and none of the solutions scaled. Here's my solution:

dd if=/dev/null of=<filename> bs=1 seek=$(echo $(stat --format=%s <filename> ) - $( tail -n1 <filename> | wc -c) | bc )

In words: Find out the length of the file you want to end up with (length of file minus length of length of its last line, using bc) and, set that position to be the end of the file (by dding one byte of /dev/null onto it).

This is fast because tail starts reading from the end, and dd will overwrite the file in place rather than copy (and parse) every line of the file, which is what the other solutions do.

NOTE: This removes the line from the file in place! Make a backup or test on a dummy file before trying it out on your own file!

TCP: can two different sockets share a port?

A server socket listens on a single port. All established client connections on that server are associated with that same listening port on the server side of the connection. An established connection is uniquely identified by the combination of client-side and server-side IP/Port pairs. Multiple connections on the same server can share the same server-side IP/Port pair as long as they are associated with different client-side IP/Port pairs, and the server would be able to handle as many clients as available system resources allow it to.

On the client-side, it is common practice for new outbound connections to use a random client-side port, in which case it is possible to run out of available ports if you make a lot of connections in a short amount of time.

Are HTTP cookies port specific?

The current cookie specification is RFC 6265, which replaces RFC 2109 and RFC 2965 (both RFCs are now marked as "Historic") and formalizes the syntax for real-world usages of cookies. It clearly states:

  1. Introduction

...

For historical reasons, cookies contain a number of security and privacy infelicities. For example, a server can indicate that a given cookie is intended for "secure" connections, but the Secure attribute does not provide integrity in the presence of an active network attacker. Similarly, cookies for a given host are shared across all the ports on that host, even though the usual "same-origin policy" used by web browsers isolates content retrieved via different ports.

And also:

8.5. Weak Confidentiality

Cookies do not provide isolation by port. If a cookie is readable by a service running on one port, the cookie is also readable by a service running on another port of the same server. If a cookie is writable by a service on one port, the cookie is also writable by a service running on another port of the same server. For this reason, servers SHOULD NOT both run mutually distrusting services on different ports of the same host and use cookies to store security sensitive information.

How to set "style=display:none;" using jQuery's attr method?

You can just use: $("#msform").hide(). This sets the element to display: none

Why em instead of px?

Avoid em or px use rem instead becuase its easier to find the computed value. But between em and px, px is better because em is hard to debug.

Failed to load JavaHL Library

i tried every single solution available and finally for me the problem was:

uninstall Native JavaHL 1.6

install everything under Subclipse from this site:

http://subclipse.tigris.org/update_1.10.x>

Java Swing revalidate() vs repaint()

Any time you do a remove() or a removeAll(), you should call

  validate();
  repaint();

after you have completed add()'ing the new components.

Calling validate() or revalidate() is mandatory when you do a remove() - see the relevant javadocs.

My own testing indicates that repaint() is also necessary. I'm not sure exactly why.

Using jQuery Fancybox or Lightbox to display a contact form

Have a look at: Greybox

It's an awesome version of lightbox that supports forms, external web pages as well as the traditional images and slideshows. It works perfectly from a link on a webpage.

You will find many information on how to use Greybox and also some great examples. Cheers Kara

How is using "<%=request.getContextPath()%>" better than "../"

request.getContextPath()- returns root path of your application, while ../ - returns parent directory of a file.

You use request.getContextPath(), as it will always points to root of your application. If you were to move your jsp file from one directory to another, nothing needs to be changed. Now, consider the second approach. If you were to move your jsp files from one folder to another, you'd have to make changes at every location where you are referring your files.

Also, better approach of using request.getContextPath() will be to set 'request.getContextPath()' in a variable and use that variable for referring your path.

<c:set var="context" value="${pageContext.request.contextPath}" />
<script src="${context}/themes/js/jquery.js"></script>

PS- This is the one reason I can figure out. Don't know if there is any more significance to it.

Scanner method to get a char

You can use the Console API (which made its appearance in Java 6) as follows:

Console cons = System.console();
if(cons != null) {
  char c = (char) cons.reader().read();  // Checking for EOF omitted
  ...
}

If you just need a single line you don't even need to go through the reader object:

String s = cons.readLine();

How to install Flask on Windows?

https://www.youtube.com/watch?v=QjtW-wnXlUY&t=38s

Follow as in the url

This is how i do : 1) create an app.py in Sublime Text or Pycharm, or whatever the ide, and in that app.py have this code

from flask import Flask

app = Flask(__name__)

@app.route('/')
def helloWorld():
    return'<h1>Hello!</h1>' 

This is a very basic program to printout a hello , to test flask is working.I would advise to create app.py in a new folder, then locate where the folder is on command prompt enter image description here type in these line of codes on command prompt

>py -m venv env
>env\Scripts\activate
>pip install flask

Then

>set FLASK_APP=app.py
>flask run

Then press enter all will work
The name of my file is app.py, give the relevant name as per your file in code line

set FLASK_APP=app.py

Also if your python path is not set, in windows python is in AppData folder its hidden, so first have to view it and set the correct path under environment variables. This is how you reach environment variables
Control panel ->> system and security ->> system ->> advanced system setting Then in system properties you get environment variables

Passing struct to function

The line function implementation should be:

void addStudent(struct student person) {

}

person is not a type but a variable, you cannot use it as the type of a function parameter.

Also, make sure your struct is defined before the prototype of the function addStudent as the prototype uses it.

How to use View.OnTouchListener instead of onClick

OnClick is triggered when the user releases the button. But if you still want to use the TouchListener you need to add it in code. It's just:

myView.setOnTouchListener(new View.OnTouchListener()
{
    // Implementation;
});

Twitter Bootstrap 3: How to center a block

center-block is bad idea as it covers a portion on your screen and you cannot click on your fields or buttons. col-md-offset-? is better option.

Use col-md-offset-3 is better option if class is col-sm-6. Just change the number to center your block.

Java - Convert String to valid URI object

If you don't like libraries, how about this?

Note that you should not use this function on the whole URL, instead you should use this on the components...e.g. just the "a b" component, as you build up the URL - otherwise the computer won't know what characters are supposed to have a special meaning and which ones are supposed to have a literal meaning.

/** Converts a string into something you can safely insert into a URL. */
public static String encodeURIcomponent(String s)
{
    StringBuilder o = new StringBuilder();
    for (char ch : s.toCharArray()) {
        if (isUnsafe(ch)) {
            o.append('%');
            o.append(toHex(ch / 16));
            o.append(toHex(ch % 16));
        }
        else o.append(ch);
    }
    return o.toString();
}

private static char toHex(int ch)
{
    return (char)(ch < 10 ? '0' + ch : 'A' + ch - 10);
}

private static boolean isUnsafe(char ch)
{
    if (ch > 128 || ch < 0)
        return true;
    return " %$&+,/:;=?@<>#%".indexOf(ch) >= 0;
}

How to redirect and append both stdout and stderr to a file with Bash?

There are two ways to do this, depending on your Bash version.

The classic and portable (Bash pre-4) way is:

cmd >> outfile 2>&1

A nonportable way, starting with Bash 4 is

cmd &>> outfile

(analog to &> outfile)

For good coding style, you should

  • decide if portability is a concern (then use classic way)
  • decide if portability even to Bash pre-4 is a concern (then use classic way)
  • no matter which syntax you use, not change it within the same script (confusion!)

If your script already starts with #!/bin/sh (no matter if intended or not), then the Bash 4 solution, and in general any Bash-specific code, is not the way to go.

Also remember that Bash 4 &>> is just shorter syntax — it does not introduce any new functionality or anything like that.

The syntax is (beside other redirection syntax) described here: http://bash-hackers.org/wiki/doku.php/syntax/redirection#appending_redirected_output_and_error_output

Amazon S3 and Cloudfront cache, how to clear cache or synchronize their cache

Don't use invalidations. They cannot be reverted and you will be charged. They only way it works for me is reducing the TTL and wait.

Regards

Javascript/Jquery Convert string to array

Since array literal notation is still valid JSON, you can use JSON.parse() to convert that string into an array, and from there, use it's values.

var test = "[1,2]";
parsedTest = JSON.parse(test); //an array [1,2]

//access like and array
console.log(parsedTest[0]); //1
console.log(parsedTest[1]); //2

Smooth scrolling when clicking an anchor link

Using JQuery:

$('a[href*=#]').click(function(){
  $('html, body').animate({
    scrollTop: $( $.attr(this, 'href') ).offset().top
  }, 500);
  return false;
});

Manifest Merger failed with multiple errors in Android Studio

If you're using multiple manifestPlaceholder items in your build.gradle file, you must add them as array elements, instead of separate items.

For example, this will cause a build error or compile error: "java.lang.RuntimeException: Manifest merger failed with multiple errors":

android {
    ...
    defaultConfig {
        manifestPlaceholders = [myKey1: "myValue1"]
        manifestPlaceholders = [myKey2: "myValue2"] // Error!
    }
}

This will fix the error:

android {
    ...
    defaultConfig {
        manifestPlaceholders = [myKey1: "myValue1", myKey2: "myValue2"]
    }
}

can't multiply sequence by non-int of type 'float'

In this line:

fund = fund * (1 + 0.01 * growthRates) + depositPerYear

growthRates is a sequence ([3,4,5,0,3]). You can't multiply that sequence by a float (0.1). It looks like what you wanted to put there was i.

Incidentally, i is not a great name for that variable. Consider something more descriptive, like growthRate or rate.

Obtaining only the filename when using OpenFileDialog property "FileName"

Use: Path.GetFileName Method

var onlyFileName = System.IO.Path.GetFileName(ofd.FileName);

Query error with ambiguous column name in SQL

This happens because there are fields with the same name in more than one table, in the query, because of the joins, so you should reference the fields differently, giving names (aliases) to the tables.

MySQL/SQL: Group by date only on a Datetime column

Or:

SELECT SUM(foo), DATE(mydate) mydate FROM a_table GROUP BY mydate;

More efficient (I think.) Because you don't have to cast mydate twice per row.

How to update and order by using ms sql

WITH    q AS
        (
        SELECT  TOP 10 *
        FROM    messages
        WHERE   status = 0
        ORDER BY
                priority DESC
        )
UPDATE  q
SET     status = 10

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

If someone want to use two or more conditions, you can do that:

your_array = [1,2,3,4]
your_string = "SOMETHING"

YourModel.where('variable1 NOT IN (?) AND variable2=(?)',Array.wrap(your_array),your_string)

C - casting int to char and append char to char

You can use itoa function to convert the integer to a string.

You can use strcat function to append characters in a string at the end of another string.

If you want to convert a integer to a character, just do the following -

int a = 65;
char c = (char) a;

Note that since characters are smaller in size than integer, this casting may cause a loss of data. It's better to declare the character variable as unsigned in this case (though you may still lose data).

To do a light reading about type conversion, go here.

If you are still having trouble, comment on this answer.

Edit

Go here for a more suitable example of joining characters.

Also some more useful link is given below -

  1. http://www.cplusplus.com/reference/clibrary/cstring/strncat/
  2. http://www.cplusplus.com/reference/clibrary/cstring/strcat/

Second Edit

char msg[200];
int msgLength;
char rankString[200];

........... // Your message has arrived
msgLength = strlen(msg);
itoa(rank, rankString, 10); // I have assumed rank is the integer variable containing the rank id

strncat( msg, rankString, (200 - msgLength) );  // msg now contains previous msg + id

// You may loose some portion of id if message length + id string length is greater than 200

Third Edit

Go to this link. Here you will find an implementation of itoa. Use that instead.

Convert alphabet letters to number in Python

If you are looking the opposite like 1 = A , 2 = B etc, you can use the following code. Please note that I have gone only up to 2 levels as I had to convert divisions in a class to A, B, C etc.

loopvariable = 0 
    numberofdivisions = 53
    while (loopvariable <numberofdivisions):
        if(loopvariable<26):
            print(chr(65+loopvariable))
        loopvariable +=1
        if(loopvariable > 26 and loopvariable <53):
            print(chr(65)+chr(65+(loopvariable-27)))

Using Composer's Autoload

In my opinion, Sergiy's answer should be the selected answer for the given question. I'm sharing my understanding.

I was looking to autoload my package files using composer which I have under the dir structure given below.

<web-root>
    |--------src/
    |           |--------App/
    |           |
    |           |--------Test/
    |
    |---------library/
    |
    |---------vendor/
    |           |
    |           |---------composer/
    |           |           |---------autoload_psr4.php
    |           |           
    |           |----------autoload.php
    |
    |-----------composer.json
    |

I'm using psr-4 autoloading specification.

Had to add below lines to the project's composer.json. I intend to place my class files inside src/App , src/Test and library directory.

"autoload": {
        "psr-4": {
            "OrgName\\AppType\\AppName\\": ["src/App", "src/Test", "library/"]
        }
    } 

This is pretty much self explaining. OrgName\AppType\AppName is my intended namespace prefix. e.g for class User in src/App/Controller/Provider/User.php -

namespace OrgName\AppType\AppName\Controller\Provider; // namespace declaration

use OrgName\AppType\AppName\Controller\Provider\User; // when using the class

Also notice "src/App", "src/Test" .. are from your web-root that is where your composer.json is. Nothing to do with the vendor dir. take a look at vendor/autoload.php

Now if composer is installed properly all that is required is #composer update

After composer update my classes loaded successfully. What I observed is that composer is adding a line in vendor/composer/autoload_psr4.php

$vendorDir = dirname(dirname(__FILE__));
$baseDir = dirname($vendorDir);

return array(
    'Monolog\\' => array($vendorDir . '/monolog/monolog/src/Monolog'),
    'OrgName\\AppType\\AppName\\' => array($baseDir . '/src/App', $baseDir . '/src/Test', $baseDir . '/library'),
);

This is how composer maps. For psr-0 mapping is in vendor/composer/autoload_classmap.php

twitter bootstrap text-center when in xs mode

Css Part is:

CSS:

@media (max-width: 767px) {

  // Align text to center.
  .text-xs-center {
    text-align: center;
  } 
}

And the HTML part will be ( this text center work only below 767px width )

HTML:

 <div class="col-xs-12 col-sm-6 text-right text-xs-center">
        <p>
            <a href="#"><i class="fa fa-facebook"></i></a> 
            <a href="#"><i class="fa fa-twitter"></i></a> 
            <a href="#"><i class="fa fa-google-plus"></i></a>
        </p>
 </div>

How to prevent the "Confirm Form Resubmission" dialog?

You could try using AJAX calls with jQuery. Like how youtube adds your comment without refreshing. This would remove the problem with refreshing overal.

You'd need to send the info necessary trough the ajax call.
I'll use the youtube comment as example.

$.ajax({
    type: 'POST',
    url: 'ajax/comment-on-video.php',
    data: {
        comment: $('#idOfInputField').val();
     },
    success: function(obj) {
        if(obj === 'true') {
            //Some code that recreates the inserted comment on the page.
        }
    }
});

You can now create the file comment-on-video.php and create something like this:

<?php
    session_start();

    if(isset($_POST['comment'])) {
        $comment = mysqli_real_escape_string($db, $_POST['comment']);
        //Given you are logged in and store the user id in the session.
        $user = $_SESSION['user_id'];

        $query = "INSERT INTO `comments` (`comment_text`, `user_id`) VALUES ($comment, $user);";
        $result = mysqli_query($db, $query);

        if($result) {
            echo true;
            exit();
        }
    }
    echo false;
    exit();
?>

C - gettimeofday for computing time?

To subtract timevals:

gettimeofday(&t0, 0);
/* ... */
gettimeofday(&t1, 0);
long elapsed = (t1.tv_sec-t0.tv_sec)*1000000 + t1.tv_usec-t0.tv_usec;

This is assuming you'll be working with intervals shorter than ~2000 seconds, at which point the arithmetic may overflow depending on the types used. If you need to work with longer intervals just change the last line to:

long long elapsed = (t1.tv_sec-t0.tv_sec)*1000000LL + t1.tv_usec-t0.tv_usec;

$(this).attr("id") not working

You can do

onchange='showHideOther.call(this);'

instead of

onchange='showHideOther(this);'

But then you also need to replace obj with this in the function.

Search of table names

I know this is an old thread, but if you prefer case-insensitive searching:

SELECT * FROM INFORMATION_SCHEMA.TABLES 
WHERE Lower(TABLE_NAME) LIKE Lower('%%')

HTML form with side by side input fields

I would go with Larry K's solution, but you can also set the display to inline-block if you want the benefits of both block and inline elements.

You can do this in the div tag by inserting:

style="display:inline-block;"

Or in a CSS stylesheet with this method:

div { display:inline-block; }

Hope it helps, but as earlier mentioned, I would personally go for Larry K's solution ;-)

Removing whitespace from strings in Java

Try this:

String str="name=john age=13 year=2001";
String s[]=str.split(" ");
StringBuilder v=new StringBuilder();
for (String string : s) {
    v.append(string);
}
str=v.toString();

How to convert "0" and "1" to false and true

How about:

return (returnValue == "1");

or as suggested below:

return (returnValue != "0");

The correct one will depend on what you are looking for as a success result.

How to display Woocommerce product price by ID number on a custom page?

Other answers work, but

To get the full/default price:

$product->get_price_html();

How to print the value of a Tensor object in TensorFlow?

The easiest[A] way to evaluate the actual value of a Tensor object is to pass it to the Session.run() method, or call Tensor.eval() when you have a default session (i.e. in a with tf.Session(): block, or see below). In general[B], you cannot print the value of a tensor without running some code in a session.

If you are experimenting with the programming model, and want an easy way to evaluate tensors, the tf.InteractiveSession lets you open a session at the start of your program, and then use that session for all Tensor.eval() (and Operation.run()) calls. This can be easier in an interactive setting, such as the shell or an IPython notebook, when it's tedious to pass around a Session object everywhere. For example, the following works in a Jupyter notebook:

with tf.Session() as sess:  print(product.eval()) 

This might seem silly for such a small expression, but one of the key ideas in Tensorflow 1.x is deferred execution: it's very cheap to build a large and complex expression, and when you want to evaluate it, the back-end (to which you connect with a Session) is able to schedule its execution more efficiently (e.g. executing independent parts in parallel and using GPUs).


[A]: To print the value of a tensor without returning it to your Python program, you can use the tf.print() operator, as Andrzej suggests in another answer. According to the official documentation:

To make sure the operator runs, users need to pass the produced op to tf.compat.v1.Session's run method, or to use the op as a control dependency for executed ops by specifying with tf.compat.v1.control_dependencies([print_op]), which is printed to standard output.

Also note that:

In Jupyter notebooks and colabs, tf.print prints to the notebook cell outputs. It will not write to the notebook kernel's console logs.

[B]: You might be able to use the tf.get_static_value() function to get the constant value of the given tensor if its value is efficiently calculable.

angular 4: *ngIf with multiple conditions

You got a ninja ')'.

Try :

<div *ngIf="currentStatus !== 'open' || currentStatus !== 'reopen'">

What's the meaning of System.out.println in Java?

Because out is being called with the System class name itself, not an instance of a class (an object), So out must be a static variable belonging to the class System. out must be instance of a class, because it is invoking the method println().

// the System class belongs to java.lang package
class System {
    public static final PrintStream out;
}
class PrintStream {
    public void println();
}

How to set bot's status

Use this:

client.user.setActivity("with depression", {
  type: "STREAMING",
  url: "https://www.twitch.tv/monstercat"
});

Running Node.js in apache?

If you're using PHP you can funnel your request to Node scripts via shell_exec, passing arguments to scripts as JSON strings in the command line. Example call:

<?php
    shell_exec("node nodeScript.js"); // without arguments
    shell_exec("node nodeScript.js '{[your JSON here]}'"); //with arguments
?>

The caveat is you need to be very careful about handling user data when it goes anywhere near a command line. Example nightmare:

<?php
    $evilUserData = "'; [malicious commands here];";
    shell_exec("node nodeScript.js '{$evilUserData}'");
?>

Catching errors in Angular HttpClient

The worse thing is not having a decent stack trace which you simply cannot generate using an HttpInterceptor (hope to stand corrected). All you get is a load of zone and rxjs useless bloat, and not the line or class that generated the error.

To do this you will need to generate a stack in an extended HttpClient, so its not advisable to do this in a production environment.

/**
 * Extended HttpClient that generates a stack trace on error when not in a production build.
 */
@Injectable()
export class TraceHttpClient extends HttpClient {
  constructor(handler: HttpHandler) {
    super(handler);
  }

  request(...args: [any]): Observable<any> {
    const stack = environment.production ? null : Error().stack;
    return super.request(...args).pipe(
      catchError((err) => {
        // tslint:disable-next-line:no-console
        if (stack) console.error('HTTP Client error stack\n', stack);
        return throwError(err);
      })
    );
  }
}

Reset input value in angular 2

Working with Angular 7 I needed to create a file upload with a description of the file.

HTML:

<div>
File Description: <input type="text" (change)="updateFileDescription($event.target.value)" #fileDescription />
</div>

<div>
<input type="file" accept="*" capture (change)="handleFileInput($event.target.files)" #fileInput /> <button class="btn btn-light" (click)="uploadFileToActivity()">Upload</button>
</div>

Here is the Component file

  @ViewChild('fileDescription') fileDescriptionInput: ElementRef;
  @ViewChild('fileInput') fileInput: ElementRef;

ClearInputs(){
        this.fileDescriptionInput.nativeElement.value = '';
        this.fileInput.nativeElement.value = '';
}

This will do the trick.

Using comma as list separator with AngularJS

Also:

angular.module('App.filters', [])
    .filter('joinBy', function () {
        return function (input,delimiter) {
            return (input || []).join(delimiter || ',');
        };
    });

And in template:

{{ itemsArray | joinBy:',' }}

How do I programmatically click on an element in JavaScript?

element.click() is a standard method outlined by the W3C DOM specification. Mozilla's Gecko/Firefox follows the standard and only allows this method to be called on INPUT elements.

Unable to get spring boot to automatically create database schema

Just add createDatabaseIfNotExist=true parameter in spring datasource url

Example: spring.datasource.url= jdbc:mysql://localhost:3306/test?createDatabaseIfNotExist=true

How can I generate UUID in C#

Be careful: while the string representations for .NET Guid and (RFC4122) UUID are identical, the storage format is not. .NET trades in little-endian bytes for the first three Guid parts.

If you are transmitting the bytes (for example, as base64), you can't just use Guid.ToByteArray() and encode it. You'll need to Array.Reverse the first three parts (Data1-3).

I do it this way:

var rfc4122bytes = Convert.FromBase64String("aguidthatIgotonthewire==");
Array.Reverse(rfc4122bytes,0,4);
Array.Reverse(rfc4122bytes,4,2);
Array.Reverse(rfc4122bytes,6,2);
var guid = new Guid(rfc4122bytes);

See this answer for the specific .NET implementation details.

Edit: Thanks to Jeff Walker, Code Ranger, for pointing out that the internals are not relevant to the format of the byte array that goes in and out of the byte-array constructor and ToByteArray().

error LNK2038: mismatch detected for '_ITERATOR_DEBUG_LEVEL': value '0' doesn't match value '2' in main.obj

Like all the other answers, I checked my Configuration Properties -> C/C++ -> Preprocessor directives.
In my case I had the NDEBUG correctly defined in Release, but I also had: _SECURE_SCL=1.

Removing that one fixed the issue.

SQL Query Where Date = Today Minus 7 Days

Using dateadd to remove a week from the current date.

datex BETWEEN DATEADD(WEEK,-1,GETDATE()) AND GETDATE()

Java generics: multiple generic parameters?

a and b must both be sets of the same type. But nothing prevents you from writing

myfunction(Set<X> a, Set<Y> b)

Move the most recent commit(s) to a new branch with Git

1) Create a new branch, which moves all your changes to new_branch.

git checkout -b new_branch

2) Then go back to old branch.

git checkout master

3) Do git rebase

git rebase -i <short-hash-of-B-commit>

4) Then the opened editor contains last 3 commit information.

...
pick <C's hash> C
pick <D's hash> D
pick <E's hash> E
...

5) Change pick to drop in all those 3 commits. Then save and close the editor.

...
drop <C's hash> C
drop <D's hash> D
drop <E's hash> E
...

6) Now last 3 commits are removed from current branch (master). Now push the branch forcefully, with + sign before branch name.

git push origin +master

How do I clear all options in a dropdown box?

This is a bit modern and pure JavaScript

document.querySelectorAll('#selectId option').forEach(option => option.remove())

MySQL vs MySQLi when using PHP

for me, prepared statements is a must-have feature. more exactly, parameter binding (which only works on prepared statements). it's the only really sane way to insert strings into SQL commands. i really don't trust the 'escaping' functions. the DB connection is a binary protocol, why use an ASCII-limited sub-protocol for parameters?

Find html label associated with a given input

If you're willing to use querySelector (and you can, even down to IE9 and sometimes IE8!), another method becomes viable.

If your form field has an ID, and you use the label's for attribute, this becomes pretty simple in modern JavaScript:

var form = document.querySelector('.sample-form');
var formFields = form.querySelectorAll('.form-field');

[].forEach.call(formFields, function (formField) {
    var inputId = formField.id;
    var label = form.querySelector('label[for=' + inputId + ']');
    console.log(label.textContent);
});

Some have noted about multiple labels; if they all use the same value for the for attribute, just use querySelectorAll instead of querySelector and loop through to get everything you need.

preventDefault() on an <a> tag

This is a non-JQuery solution I just tested and it works.

<html lang="en">
<head>
<script type="text/javascript">
addEventListener("load",function(){
    var links= document.getElementsByTagName("a");
    for (var i=0;i<links.length;i++){
        links[i].addEventListener("click",function(e){
        alert("NOPE!, I won't take you there haha");
        //prevent event action
        e.preventDefault();
        })
    }
}); 

</script>
</head>
<body>
<div>
<ul>
    <li><a href="http://www.google.com">Google</a></li>
    <li><a href="http://www.facebook.com">Facebook</a></li>
    <p id="p1">Paragraph</p>
</ul>
</div>
<p>By Jefrey Bulla</p>
</body>
</html>

How do I add a tool tip to a span element?

Here's the simple, built-in way:

<span title="My tip">text</span>

That gives you plain text tooltips. If you want rich tooltips, with formatted HTML in them, you'll need to use a library to do that. Fortunately there are loads of those.

"The operation is not valid for the state of the transaction" error and transaction scope

I also come across same problem, I changed transaction timeout to 15 minutes and it works. I hope this helps.

TransactionOptions options = new TransactionOptions();
options.IsolationLevel = System.Transactions.IsolationLevel.ReadCommitted;
options.Timeout = new TimeSpan(0, 15, 0);
using (TransactionScope scope = new TransactionScope(TransactionScopeOption.Required,options))
{
    sp1();
    sp2();
    ...

}

How do you execute SQL from within a bash script?

As Bash doesn't have built in sql database connectivity... you will need to use some sort of third party tool.

Getting Class type from String

Class<?> cls = Class.forName(className);

But your className should be fully-qualified - i.e. com.mycompany.MyClass

Integration Testing POSTing an entire object to Spring MVC controller

Another way to solve with Reflection, but without marshalling:

I have this abstract helper class:

public abstract class MvcIntegrationTestUtils {

       public static MockHttpServletRequestBuilder postForm(String url,
                 Object modelAttribute, String... propertyPaths) {

              try {
                     MockHttpServletRequestBuilder form = post(url).characterEncoding(
                           "UTF-8").contentType(MediaType.APPLICATION_FORM_URLENCODED);

                     for (String path : propertyPaths) {
                            form.param(path, BeanUtils.getProperty(modelAttribute, path));
                     }

                     return form;

              } catch (Exception e) {
                     throw new RuntimeException(e);
              }
     }
}

You use it like this:

// static import (optional)
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;

// in your test method, populate your model attribute object (yes, works with nested properties)
BlogSetup bgs = new BlogSetup();
      bgs.getBlog().setBlogTitle("Test Blog");
      bgs.getUser().setEmail("[email protected]");
    bgs.getUser().setFirstName("Administrator");
      bgs.getUser().setLastName("Localhost");
      bgs.getUser().setPassword("password");

// finally put it together
mockMvc.perform(
            postForm("/blogs/create", bgs, "blog.blogTitle", "user.email",
                    "user.firstName", "user.lastName", "user.password"))
            .andExpect(status().isOk())

I have deduced it is better to be able to mention the property paths when building the form, since I need to vary that in my tests. For example, I might want to check if I get a validation error on a missing input and I'll leave out the property path to simulate the condition. I also find it easier to build my model attributes in a @Before method.

The BeanUtils is from commons-beanutils:

    <dependency>
        <groupId>commons-beanutils</groupId>
        <artifactId>commons-beanutils</artifactId>
        <version>1.8.3</version>
        <scope>test</scope>
    </dependency>

How do I execute code AFTER a form has loaded?

I sometimes use (in Load)

this.BeginInvoke((MethodInvoker) delegate {
  // some code
});

or

this.BeginInvoke((MethodInvoker) this.SomeMethod);

(change "this" to your form variable if you are handling the event on an instance other than "this").

This pushes the invoke onto the windows-forms loop, so it gets processed when the form is processing the message queue.

[updated on request]

The Control.Invoke/Control.BeginInvoke methods are intended for use with threading, and are a mechanism to push work onto the UI thread. Normally this is used by worker threads etc. Control.Invoke does a synchronous call, where-as Control.BeginInvoke does an asynchronous call.

Normally, these would be used as:

SomeCodeOrEventHandlerOnAWorkerThread()
{
  // this code running on a worker thread...
  string newText = ExpensiveMethod(); // perhaps a DB/web call

  // now ask the UI thread to update itself
  this.Invoke((MethodInvoker) delegate {
      // this code runs on the UI thread!
      this.Text = newText;
  });
}

It does this by pushing a message onto the windows message queue; the UI thread (at some point) de-queues the message, processes the delegate, and signals the worker that it completed... so far so good ;-p

OK; so what happens if we use Control.Invoke / Control.BeginInvoke on the UI thread? It copes... if you call Control.Invoke, it is sensible enough to know that blocking on the message queue would cause an immediate deadlock - so if you are already on the UI thread it simply runs the code immediately... so that doesn't help us...

But Control.BeginInvoke works differently: it always pushes work onto the queue, even it we are already on the UI thread. This makes a really simply way of saying "in a moment", but without the inconvenience of timers etc (which would still have to do the same thing anyway!).

DBCC SHRINKFILE on log file not reducing size even after BACKUP LOG TO DISK

In addition to the steps you have already taken, you will need to set the recovery mode to simple before you can shrink the log.

THIS IS NOT A RECOMMENDED PRACTICE for production systems... You will lose your ability to recover to a point in time from previous backups/log files.

See example B on this DBCC SHRINKFILE (Transact-SQL) msdn page for an example, and explanation.

How to abort a Task like aborting a Thread (Thread.Abort method)?

The guidance on not using a thread abort is controversial. I think there is still a place for it but in exceptional circumstance. However you should always attempt to design around it and see it as a last resort.

Example;

You have a simple windows form application that connects to a blocking synchronous web service. Within which it executes a function on the web service within a Parallel loop.

CancellationTokenSource cts = new CancellationTokenSource();
ParallelOptions po = new ParallelOptions();
po.CancellationToken = cts.Token;
po.MaxDegreeOfParallelism = System.Environment.ProcessorCount;

Parallel.ForEach(iListOfItems, po, (item, loopState) =>
{

    Thread.Sleep(120000); // pretend web service call

});

Say in this example, the blocking call takes 2 mins to complete. Now I set my MaxDegreeOfParallelism to say ProcessorCount. iListOfItems has 1000 items within it to process.

The user clicks the process button and the loop commences, we have 'up-to' 20 threads executing against 1000 items in the iListOfItems collection. Each iteration executes on its own thread. Each thread will utilise a foreground thread when created by Parallel.ForEach. This means regardless of the main application shutdown, the app domain will be kept alive until all threads have finished.

However the user needs to close the application for some reason, say they close the form. These 20 threads will continue to execute until all 1000 items are processed. This is not ideal in this scenario, as the application will not exit as the user expects and will continue to run behind the scenes, as can be seen by taking a look in task manger.

Say the user tries to rebuild the app again (VS 2010), it reports the exe is locked, then they would have to go into task manager to kill it or just wait until all 1000 items are processed.

I would not blame you for saying, but of course! I should be cancelling these threads using the CancellationTokenSource object and calling Cancel ... but there are some problems with this as of .net 4.0. Firstly this is still never going to result in a thread abort which would offer up an abort exception followed by thread termination, so the app domain will instead need to wait for the threads to finish normally, and this means waiting for the last blocking call, which would be the very last running iteration (thread) that ultimately gets to call po.CancellationToken.ThrowIfCancellationRequested. In the example this would mean the app domain could still stay alive for up to 2 mins, even though the form has been closed and cancel called.

Note that Calling Cancel on CancellationTokenSource does not throw an exception on the processing thread(s), which would indeed act to interrupt the blocking call similar to a thread abort and stop the execution. An exception is cached ready for when all the other threads (concurrent iterations) eventually finish and return, the exception is thrown in the initiating thread (where the loop is declared).

I chose not to use the Cancel option on a CancellationTokenSource object. This is wasteful and arguably violates the well known anti-patten of controlling the flow of the code by Exceptions.

Instead, it is arguably 'better' to implement a simple thread safe property i.e. Bool stopExecuting. Then within the loop, check the value of stopExecuting and if the value is set to true by the external influence, we can take an alternate path to close down gracefully. Since we should not call cancel, this precludes checking CancellationTokenSource.IsCancellationRequested which would otherwise be another option.

Something like the following if condition would be appropriate within the loop;

if (loopState.ShouldExitCurrentIteration || loopState.IsExceptional || stopExecuting) {loopState.Stop(); return;}

The iteration will now exit in a 'controlled' manner as well as terminating further iterations, but as I said, this does little for our issue of having to wait on the long running and blocking call(s) that are made within each iteration (parallel loop thread), since these have to complete before each thread can get to the option of checking if it should stop.

In summary, as the user closes the form, the 20 threads will be signaled to stop via stopExecuting, but they will only stop when they have finished executing their long running function call.

We can't do anything about the fact that the application domain will always stay alive and only be released when all foreground threads have completed. And this means there will be a delay associated with waiting for any blocking calls made within the loop to complete.

Only a true thread abort can interrupt the blocking call, and you must mitigate leaving the system in a unstable/undefined state the best you can in the aborted thread's exception handler which goes without question. Whether that's appropriate is a matter for the programmer to decide, based on what resource handles they chose to maintain and how easy it is to close them in a thread's finally block. You could register with a token to terminate on cancel as a semi workaround i.e.

CancellationTokenSource cts = new CancellationTokenSource();
ParallelOptions po = new ParallelOptions();
po.CancellationToken = cts.Token;
po.MaxDegreeOfParallelism = System.Environment.ProcessorCount;

Parallel.ForEach(iListOfItems, po, (item, loopState) =>
{

    using (cts.Token.Register(Thread.CurrentThread.Abort))
    {
        Try
        {
           Thread.Sleep(120000); // pretend web service call          
        }
        Catch(ThreadAbortException ex)
        {
           // log etc.
        }
        Finally
        {
          // clean up here
        }
    }

});

but this will still result in an exception in the declaring thread.

All things considered, interrupt blocking calls using the parallel.loop constructs could have been a method on the options, avoiding the use of more obscure parts of the library. But why there is no option to cancel and avoid throwing an exception in the declaring method strikes me as a possible oversight.

Detect current device with UI_USER_INTERFACE_IDIOM() in Swift

Swift 2.x:

Adding to Beslav Turalov answer's the new entry iPad Pro can easily be find with this line

to detect iPad Pro

struct DeviceType
{
    ...
    static let IS_IPAD_PRO = UIDevice.currentDevice().userInterfaceIdiom == .Pad && ScreenSize.SCREEN_MAX_LENGTH == 1366.0
}

Swift 3 (TV and car added):

struct ScreenSize
{
    static let SCREEN_WIDTH         = UIScreen.main.bounds.size.width
    static let SCREEN_HEIGHT        = UIScreen.main.bounds.size.height
    static let SCREEN_MAX_LENGTH    = max(ScreenSize.SCREEN_WIDTH, ScreenSize.SCREEN_HEIGHT)
    static let SCREEN_MIN_LENGTH    = min(ScreenSize.SCREEN_WIDTH, ScreenSize.SCREEN_HEIGHT)
}

struct DeviceType
{
    static let IS_IPHONE            = UIDevice.current.userInterfaceIdiom == .phone
    static let IS_IPHONE_4_OR_LESS  = UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH < 568.0
    static let IS_IPHONE_5          = UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH == 568.0
    static let IS_IPHONE_6          = UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH == 667.0
    static let IS_IPHONE_6P         = UIDevice.current.userInterfaceIdiom == .phone && ScreenSize.SCREEN_MAX_LENGTH == 736.0
    static let IS_IPHONE_7          = IS_IPHONE_6
    static let IS_IPHONE_7P         = IS_IPHONE_6P
    static let IS_IPAD              = UIDevice.current.userInterfaceIdiom == .pad && ScreenSize.SCREEN_MAX_LENGTH == 1024.0
    static let IS_IPAD_PRO_9_7      = IS_IPAD
    static let IS_IPAD_PRO_12_9     = UIDevice.current.userInterfaceIdiom == .pad && ScreenSize.SCREEN_MAX_LENGTH == 1366.0
    static let IS_TV                = UIDevice.current.userInterfaceIdiom == .tv
    static let IS_CAR_PLAY          = UIDevice.current.userInterfaceIdiom == .carPlay
}

struct Version{
    static let SYS_VERSION_FLOAT = (UIDevice.current.systemVersion as NSString).floatValue
    static let iOS7 = (Version.SYS_VERSION_FLOAT < 8.0 && Version.SYS_VERSION_FLOAT >= 7.0)
    static let iOS8 = (Version.SYS_VERSION_FLOAT >= 8.0 && Version.SYS_VERSION_FLOAT < 9.0)
    static let iOS9 = (Version.SYS_VERSION_FLOAT >= 9.0 && Version.SYS_VERSION_FLOAT < 10.0)
    static let iOS10 = (Version.SYS_VERSION_FLOAT >= 10.0 && Version.SYS_VERSION_FLOAT < 11.0)
}

USAGE:

if DeviceType.IS_IPHONE_7P { print("iPhone 7 plus") }
if DeviceType.IS_IPAD_PRO_9_7 && Version.iOS10 { print("iPad pro 9.7 with iOS 10 version") }

How to loop through file names returned by find?

TL;DR: If you're just here for the most correct answer, you probably want my personal preference, find . -name '*.txt' -exec process {} \; (see the bottom of this post). If you have time, read through the rest to see several different ways and the problems with most of them.


The full answer:

The best way depends on what you want to do, but here are a few options. As long as no file or folder in the subtree has whitespace in its name, you can just loop over the files:

for i in $x; do # Not recommended, will break on whitespace
    process "$i"
done

Marginally better, cut out the temporary variable x:

for i in $(find -name \*.txt); do # Not recommended, will break on whitespace
    process "$i"
done

It is much better to glob when you can. White-space safe, for files in the current directory:

for i in *.txt; do # Whitespace-safe but not recursive.
    process "$i"
done

By enabling the globstar option, you can glob all matching files in this directory and all subdirectories:

# Make sure globstar is enabled
shopt -s globstar
for i in **/*.txt; do # Whitespace-safe and recursive
    process "$i"
done

In some cases, e.g. if the file names are already in a file, you may need to use read:

# IFS= makes sure it doesn't trim leading and trailing whitespace
# -r prevents interpretation of \ escapes.
while IFS= read -r line; do # Whitespace-safe EXCEPT newlines
    process "$line"
done < filename

read can be used safely in combination with find by setting the delimiter appropriately:

find . -name '*.txt' -print0 | 
    while IFS= read -r -d '' line; do 
        process "$line"
    done

For more complex searches, you will probably want to use find, either with its -exec option or with -print0 | xargs -0:

# execute `process` once for each file
find . -name \*.txt -exec process {} \;

# execute `process` once with all the files as arguments*:
find . -name \*.txt -exec process {} +

# using xargs*
find . -name \*.txt -print0 | xargs -0 process

# using xargs with arguments after each filename (implies one run per filename)
find . -name \*.txt -print0 | xargs -0 -I{} process {} argument

find can also cd into each file's directory before running a command by using -execdir instead of -exec, and can be made interactive (prompt before running the command for each file) using -ok instead of -exec (or -okdir instead of -execdir).

*: Technically, both find and xargs (by default) will run the command with as many arguments as they can fit on the command line, as many times as it takes to get through all the files. In practice, unless you have a very large number of files it won't matter, and if you exceed the length but need them all on the same command line, you're SOL find a different way.

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

JSmooth .exe wrapper

JSmooth is a Java Executable Wrapper. It creates native Windows launchers (standard .exe) for your Java applications. It makes java deployment much smoother and user-friendly, as it is able to find any installed Java VM by itself. When no VM is available, the wrapper can automatically download and install a suitable JVM, or simply display a message or redirect the user to a website.

JSmooth provides a variety of wrappers for your java application, each of them having their own behavior: Choose your flavor!

Download: http://jsmooth.sourceforge.net/

JarToExe 1.8 Jar2Exe is a tool to convert jar files into exe files. Following are the main features as describe on their website:

Can generate “Console”, “Windows GUI”, “Windows Service” three types of .exe files.

Generated .exe files can add program icons and version information. Generated .exe files can encrypt and protect java programs, no temporary files will be generated when the program runs.

Generated .exe files provide system tray icon support. Generated .exe files provide record system event log support. Generated windows service .exe files are able to install/uninstall itself, and support service pause/continue.

Executor

Package your Java application as a jar, and Executor will turn the jar into a Windows .exe file, indistinguishable from a native application. Simply double-clicking the .exe file will invoke the Java Runtime Environment and launch your application.

How to determine if a string is a number with C++?

I've found the following code to be the most robust (c++11). It catches both integers and floats.

#include <regex>
bool isNumber( std::string token )
{
    return std::regex_match( token, std::regex( ( "((\\+|-)?[[:digit:]]+)(\\.(([[:digit:]]+)?))?" ) ) );
}

Priority queue in .Net

I found one by Julian Bucknall on his blog here - http://www.boyet.com/Articles/PriorityQueueCSharp3.html

We modified it slightly so that low-priority items on the queue would eventually 'bubble-up' to the top over time, so they wouldn't suffer starvation.

How to show the last queries executed on MySQL?

You can enable a general query log for that sort of diagnostic. Generally you don't log all SELECT queries on a production server though, it's a performance killer.

Edit your MySQL config, e.g. /etc/mysql/my.cnf - look for, or add, a line like this

[mysqld]
log = /var/log/mysql/mysql.log

Restart mysql to pick up that change, now you can

tail -f /var/log/mysql/mysql.log

Hey presto, you can watch the queries as they come in.

How to make an Android device vibrate? with different frequency?

Vibrating in Patterns/Waves:

import android.os.Vibrator;
...
// Vibrate for 500ms, pause for 500ms, then start again
private static final long[] VIBRATE_PATTERN = { 500, 500 };

mVibrator = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    // API 26 and above
    mVibrator.vibrate(VibrationEffect.createWaveform(VIBRATE_PATTERN, 0));
} else {
    // Below API 26
    mVibrator.vibrate(VIBRATE_PATTERN, 0);
}

Plus

The necessary permission in AndroidManifest.xml:

<uses-permission android:name="android.permission.VIBRATE"/>

What are the differences between a HashMap and a Hashtable in Java?

In addition to what izb said, HashMap allows null values, whereas the Hashtable does not.

Also note that Hashtable extends the Dictionary class, which as the Javadocs state, is obsolete and has been replaced by the Map interface.