pip is not able to install packages correctly: Permission denied error

Set up a virtualenv:

% curl -kLso /tmp/get-pip.py https://bootstrap.pypa.io/get-pip.py 
% sudo python /tmp/get-pip.py

These commands install pip into the global site-packages directory.

% sudo pip install virtualenv

and ditto for virtualenv:

% mkdir -p ~/.virtualenvs

I like my virtualenvs under one tree in my home directory called .virtualenvs

% virtualenv ~/.virtualenvs/lxmltest

Creates a virtualenv.

% . ~/.virtualenvs/lxmltest/bin/activate

Removes the need to specify the full path to pip/python in this virtualenv.

% pip install lxml

Alternatively execute ~/.virtualenvs/lxmltest/bin/pip install lxml if you chose not to follow the previous step. Note, I'm not sure how far along you are, so some of these steps can be safely skipped. Of course, if you mess something up, you can always rm -Rf ~/.virtualenvs/lxmltest and start again from a new virtualenv.

Debugging the error "gcc: error: x86_64-linux-gnu-gcc: No such file or directory"

sudo apt-get -y install python-software-properties && \
sudo apt-get -y install software-properties-common && \
sudo apt-get -y install gcc make build-essential libssl-dev libffi-dev python-dev

You need the libssl-dev and libffi-dev if especially you are trying to install python's cryptography libraries or python libs that depend on it(eg ansible)

java.lang.ClassNotFoundException: Didn't find class on path: dexpathlist

In my case this issue arose because of Kotlin. In my existing code there was a class that was written Kotlin. I built the app, it installed and as soon as first activity opened app crashed. in the logcat this error was being shown. I then updated my Kotlin version from Kotlin website in app gradle file. Build the app again and it worked fine then.

Change HTML email body font type and size in VBA

I did a little research and was able to write this code:

strbody = "<BODY style=font-size:11pt;font-family:Calibri>Good Morning;<p>We have completed our main aliasing process for today.  All assigned firms are complete.  Please feel free to respond with any questions.<p>Thank you.</BODY>"

apparently by setting the "font-size=11pt" instead of setting the font size <font size=5>, It allows you to select a specific font size like you normally would in a text editor, as opposed to selecting a value from 1-7 like my code was originally.

This link from simpLE MAn gave me some good info.

Installing PIL with pip

For Ubuntu, PIL is not working any more. I always get:

No matching distribution found for PIL

So install python-imaging:

sudo apt-get install python-imaging

libpthread.so.0: error adding symbols: DSO missing from command line

Background

The DSO missing from command line message will be displayed when the linker does not find the required symbol with it's normal search but the symbol is available in one of the dependencies of a directly specified dynamic library.

In the past the linker considered symbols in dependencies of specified languages to be available. But that changed in some later version and now the linker enforces a more strict view of what is available. The message thus is intended to help with that transition.

What to do?

If you are the maintainer of the software

You should solve this problem by making sure that all libraries that are needed to satisfy the needed symbols are directly specified on the linker command line. Also keep in mind that order often matters.

If you are just trying to compile the software

As a workaround it's possible to switch back to the more permissive view of what symbols are available by using the option -Wl,--copy-dt-needed-entries.

Common ways to inject this into a build are to export LDFLAGS before running configure or similar like this:

export LDFLAGS="-Wl,--copy-dt-needed-entries"

Sometimes passing LDFLAGS="-Wl,--copy-dt-needed-entries" directly to make might also work.

HTML5 Canvas Resize (Downscale) Image High Quality?

Fast canvas resample with good quality: http://jsfiddle.net/9g9Nv/442/

Update: version 2.0 (faster, web workers + transferable objects) - https://github.com/viliusle/Hermite-resize

/**
 * Hermite resize - fast image resize/resample using Hermite filter. 1 cpu version!
 * 
 * @param {HtmlElement} canvas
 * @param {int} width
 * @param {int} height
 * @param {boolean} resize_canvas if true, canvas will be resized. Optional.
 */
function resample_single(canvas, width, height, resize_canvas) {
    var width_source = canvas.width;
    var height_source = canvas.height;
    width = Math.round(width);
    height = Math.round(height);

    var ratio_w = width_source / width;
    var ratio_h = height_source / height;
    var ratio_w_half = Math.ceil(ratio_w / 2);
    var ratio_h_half = Math.ceil(ratio_h / 2);

    var ctx = canvas.getContext("2d");
    var img = ctx.getImageData(0, 0, width_source, height_source);
    var img2 = ctx.createImageData(width, height);
    var data = img.data;
    var data2 = img2.data;

    for (var j = 0; j < height; j++) {
        for (var i = 0; i < width; i++) {
            var x2 = (i + j * width) * 4;
            var weight = 0;
            var weights = 0;
            var weights_alpha = 0;
            var gx_r = 0;
            var gx_g = 0;
            var gx_b = 0;
            var gx_a = 0;
            var center_y = (j + 0.5) * ratio_h;
            var yy_start = Math.floor(j * ratio_h);
            var yy_stop = Math.ceil((j + 1) * ratio_h);
            for (var yy = yy_start; yy < yy_stop; yy++) {
                var dy = Math.abs(center_y - (yy + 0.5)) / ratio_h_half;
                var center_x = (i + 0.5) * ratio_w;
                var w0 = dy * dy; //pre-calc part of w
                var xx_start = Math.floor(i * ratio_w);
                var xx_stop = Math.ceil((i + 1) * ratio_w);
                for (var xx = xx_start; xx < xx_stop; xx++) {
                    var dx = Math.abs(center_x - (xx + 0.5)) / ratio_w_half;
                    var w = Math.sqrt(w0 + dx * dx);
                    if (w >= 1) {
                        //pixel too far
                        continue;
                    }
                    //hermite filter
                    weight = 2 * w * w * w - 3 * w * w + 1;
                    var pos_x = 4 * (xx + yy * width_source);
                    //alpha
                    gx_a += weight * data[pos_x + 3];
                    weights_alpha += weight;
                    //colors
                    if (data[pos_x + 3] < 255)
                        weight = weight * data[pos_x + 3] / 250;
                    gx_r += weight * data[pos_x];
                    gx_g += weight * data[pos_x + 1];
                    gx_b += weight * data[pos_x + 2];
                    weights += weight;
                }
            }
            data2[x2] = gx_r / weights;
            data2[x2 + 1] = gx_g / weights;
            data2[x2 + 2] = gx_b / weights;
            data2[x2 + 3] = gx_a / weights_alpha;
        }
    }
    //clear and resize canvas
    if (resize_canvas === true) {
        canvas.width = width;
        canvas.height = height;
    } else {
        ctx.clearRect(0, 0, width_source, height_source);
    }

    //draw
    ctx.putImageData(img2, 0, 0);
}

How to apply font anti-alias effects in CSS?

here you go Sir :-)

.myElement{
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

.myElement{
    text-shadow: rgba(0,0,0,.01) 0 0 1px;
}

How to increase IDE memory limit in IntelliJ IDEA on Mac?

I use Mac and Idea 14.1.7. Found idea.vmoptions file here: /Applications/IntelliJ IDEA 14.app/Contents/bin

details

How can I set a custom baud rate on Linux?

For Mac users (possibly also for some Linux distributions)

stty ospeed 999999

stty ispeed 999999

ld cannot find -l<library>

you can add the Path to coinhsl lib to LD_LIBRARY_PATH variable. May be that will help.

export LD_LIBRARY_PATH=/xx/yy/zz:$LD_LIBRARY_PATH

where /xx/yy/zz represent the path to coinhsl lib.

Webfont Smoothing and Antialiasing in Firefox and Opera

Well, Firefox does not support something like that.

In the reference page from Mozilla specifies font-smooth as CSS property controls the application of anti-aliasing when fonts are rendered, but this property has been removed from this specification and is currently not on the standard track.

This property is only supported in Webkit browsers.

If you want an alternative you can check this:

What is the difference between 'typedef' and 'using' in C++11?

They are largely the same, except that:

The alias declaration is compatible with templates, whereas the C style typedef is not.

Pip install Matplotlib error with virtualenv

As I have struggled with this issue twice (even after fresh kubuntu 15.04 install) and installing freetype did not solve anything, I investigated further.

The solution:
From github issue:

This bug only occurs if pkg-config is not installed;
a simple
sudo apt-get install pkg-config
will shore up the include paths for now.

After this installation proceeds smoothly.

How to install OpenSSL for Python

SSL development libraries have to be installed

CentOS:

$ yum install openssl-devel libffi-devel

Ubuntu:

$ apt-get install libssl-dev libffi-dev

OS X (with Homebrew installed):

$ brew install openssl

css transform, jagged edges in chrome

You might be able to mask the jagging using blurred box-shadows. Using -webkit-box-shadow instead of box-shadow will make sure it doesn't affect non-webkit browsers. You might want to check Safari and the mobile webkit browsers though.

The result is somewhat better, but still a lot less good then with the other browsers:

with box shadow (underside)

libxml install error using pip

On osx 10.10.5 and in a virtualenv, maybe you can resolve that problem like below:

sudo C_INCLUDE_PATH=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/include/libxml2:/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/include/libxml2/libxml:/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/include pip install -r lxml

HTML5 Canvas and Anti-aliasing

You may translate canvas by half-pixel distance.

ctx.translate(0.5, 0.5);

Initially the canvas positioning point between the physical pixels.

Forcing anti-aliasing using css: Is this a myth?

Adding the following line of CSS works for Chrome, but not Internet Explorer or Firefox.

text-shadow: #fff 0px 1px 1px;

What is the strict aliasing rule?

A typical situation where you encounter strict aliasing problems is when overlaying a struct (like a device/network msg) onto a buffer of the word size of your system (like a pointer to uint32_ts or uint16_ts). When you overlay a struct onto such a buffer, or a buffer onto such a struct through pointer casting you can easily violate strict aliasing rules.

So in this kind of setup, if I want to send a message to something I'd have to have two incompatible pointers pointing to the same chunk of memory. I might then naively code something like this:

typedef struct Msg
{
    unsigned int a;
    unsigned int b;
} Msg;

void SendWord(uint32_t);

int main(void)
{
    // Get a 32-bit buffer from the system
    uint32_t* buff = malloc(sizeof(Msg));
    
    // Alias that buffer through message
    Msg* msg = (Msg*)(buff);
    
    // Send a bunch of messages    
    for (int i = 0; i < 10; ++i)
    {
        msg->a = i;
        msg->b = i+1;
        SendWord(buff[0]);
        SendWord(buff[1]);   
    }
}

The strict aliasing rule makes this setup illegal: dereferencing a pointer that aliases an object that is not of a compatible type or one of the other types allowed by C 2011 6.5 paragraph 7¹ is undefined behavior. Unfortunately, you can still code this way, maybe get some warnings, have it compile fine, only to have weird unexpected behavior when you run the code.

(GCC appears somewhat inconsistent in its ability to give aliasing warnings, sometimes giving us a friendly warning and sometimes not.)

To see why this behavior is undefined, we have to think about what the strict aliasing rule buys the compiler. Basically, with this rule, it doesn't have to think about inserting instructions to refresh the contents of buff every run of the loop. Instead, when optimizing, with some annoyingly unenforced assumptions about aliasing, it can omit those instructions, load buff[0] and buff[1] into CPU registers once before the loop is run, and speed up the body of the loop. Before strict aliasing was introduced, the compiler had to live in a state of paranoia that the contents of buff could change by any preceding memory stores. So to get an extra performance edge, and assuming most people don't type-pun pointers, the strict aliasing rule was introduced.

Keep in mind, if you think the example is contrived, this might even happen if you're passing a buffer to another function doing the sending for you, if instead you have.

void SendMessage(uint32_t* buff, size_t size32)
{
    for (int i = 0; i < size32; ++i) 
    {
        SendWord(buff[i]);
    }
}

And rewrote our earlier loop to take advantage of this convenient function

for (int i = 0; i < 10; ++i)
{
    msg->a = i;
    msg->b = i+1;
    SendMessage(buff, 2);
}

The compiler may or may not be able to or smart enough to try to inline SendMessage and it may or may not decide to load or not load buff again. If SendMessage is part of another API that's compiled separately, it probably has instructions to load buff's contents. Then again, maybe you're in C++ and this is some templated header only implementation that the compiler thinks it can inline. Or maybe it's just something you wrote in your .c file for your own convenience. Anyway undefined behavior might still ensue. Even when we know some of what's happening under the hood, it's still a violation of the rule so no well defined behavior is guaranteed. So just by wrapping in a function that takes our word delimited buffer doesn't necessarily help.

So how do I get around this?

Use a union. Most compilers support this without complaining about strict aliasing. This is allowed in C99 and explicitly allowed in C11.
```
  union {
      Msg msg;
      unsigned int asBuffer[sizeof(Msg)/sizeof(unsigned int)];
  };
```
You can disable strict aliasing in your compiler (f[no-]strict-aliasing in gcc))
You can use char* for aliasing instead of your system's word. The rules allow an exception for char* (including signed char and unsigned char). It's always assumed that char* aliases other types. However this won't work the other way: there's no assumption that your struct aliases a buffer of chars.

Beginner beware

This is only one potential minefield when overlaying two types onto each other. You should also learn about endianness, word alignment, and how to deal with alignment issues through packing structs correctly.

Footnote

¹ The types that C 2011 6.5 7 allows an lvalue to access are:

a type compatible with the effective type of the object,
a qualified version of a type compatible with the effective type of the object,
a type that is the signed or unsigned type corresponding to the effective type of the object,
a type that is the signed or unsigned type corresponding to a qualified version of the effective type of the object,
an aggregate or union type that includes one of the aforementioned types among its members (including, recursively, a member of a subaggregate or contained union), or
a character type.

E: gnupg, gnupg2 and gnupg1 do not seem to be installed, but one of them is required for this operation

Just install the updated versions of all of them.

apt-get install -y gnupg2 gnupg gnupg1

Fragment onCreateView and onActivityCreated called twice

It looks to me like it's because you are instantiating your TabListener every time... so the system is recreating your fragment from the savedInstanceState and then you are doing it again in your onCreate.

You should wrap that in a if(savedInstanceState == null) so it only fires if there is no savedInstanceState.

Working with time DURATION, not time of day

The custom format hh:mm only shows the number of hours correctly up to 23:59, after that, you get the remainder, less full days. For example, 48 hours would be displayed as 00:00, even though the underlaying value is correct.

To correctly display duration in hours and seconds (below or beyond a full day), you should use the custom format [h]:mm;@ In this case, 48 hours would be displayed as 48:00.

Cheers.

"SSL certificate verify failed" using pip to install packages

You can try sudo apt-get upgrade to get the latest packages. It fixed the issue on my machine.

Matching a space in regex

Here is a everything you need to know about whitespace in regular expressions:

[[:blank:]] Space or tab only
[[:space:]] Whitespace
\s Any whitespace character
\v Vertical whitespace
\h Horizontal whitespace
x Ignore whitespace

SQLAlchemy equivalent to SQL "LIKE" statement

Using PostgreSQL like (see accepted answer above) somehow didn't work for me although cases matched, but ilike (case insensisitive like) does.

Binding value to style

Turns out the binding of style to a string doesn't work. The solution would be to bind the background of the style.

 <div class="circle" [style.background]="color">

Open a new tab in the background?

As far as I remember, this is controlled by browser settings. In other words: user can chose whether they would like to open new tab in the background or foreground. Also they can chose whether new popup should open in new tab or just... popup.

For example in firefox preferences:

Firefox setup example

Notice the last option.

How to check internet access on Android? InetAddress never times out

If you are using API 23 or above, you can now check whether or not internet is active using NetworkCapabilities.NET_CAPABILITY_VALIDATED, which is backed by Google's own ping service.

ConnectivityManager.NetworkCallback networkCallback = new ConnectivityManager.NetworkCallback() {
    @Override
    public void onLost(Network network) {
        // handle network lost
    }

    @Override
    public void onAvailable(Network network) {
        ConnectivityManager cm = (ConnectivityManager) getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo info = cm.getNetworkInfo(network);
        boolean isConnected = (info != null && info.isConnectedOrConnecting());

        if (isConnected) {
            NetworkCapabilities nc = cm.getNetworkCapabilities(network);
            if (nc != null) {
                boolean isInternetValid = nc.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED);
                if (isInternetValid) {
                    // internet is valid
                }
            }
        }
    }
};

NetworkRequest request = new NetworkRequest.Builder().addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET).build();
ConnectivityManager connectivityManager = (ConnectivityManager) getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
connectivityManager.registerNetworkCallback(request, networkCallback);

How to import an excel file in to a MySQL database

Fastest and simpliest way is to save XLS as ODS (open document spreasheet) and import it from PhpMyAdmin

What is the difference between int, Int16, Int32 and Int64?

They both are indeed synonymous, However i found the small difference between them,

1)You cannot use Int32 while creatingenum

enum Test : Int32
{ XXX = 1   // gives you compilation error
}

enum Test : int
{ XXX = 1   // Works fine
}

2) Int32 comes under System declaration. if you remove using.System you will get compilation error but not in case for int

Rails: Can't verify CSRF token authenticity when making a POST request

If you only want to skip CSRF protection for one or more controller actions (instead of the entire controller), try this

skip_before_action :verify_authenticity_token, only [:webhook, :index, :create]

Where [:webhook, :index, :create] will skip the check for those 3 actions, but you can change to whichever you want to skip

Java math function to convert positive int to negative and negative to positive?

You can use Math:

int x = Math.abs(-5);

How do I Convert DateTime.now to UTC in Ruby?

In irb:

>>d = DateTime.now
=> #<DateTime: 11783702280454271/4800000000,5/12,2299161>
>> "#{d.hour.to_i - d.zone.to_i}:#{d.min}:#{d.sec}"
=> "11:16:41"

will convert the time to the utc. But as posted if it is just Time you can use:

Time.now.utc

and get it straight away.

read string from .resx file in C#

The Simplest Way to get value from resource file. Add Resource file in the project. Now get the string where you want to add like in my case it was text block(SilverLight). No need to add any namespace also.Its working fine in my case

txtStatus.Text = Constants.RefractionUpdateMessage;

Constants is my resource file name in the project.

How do I localize the jQuery UI Datepicker?

This solution may help.

_x000D_

$(document).ready(function () {_x000D_
  var userLang = navigator.language || navigator.userLanguage;_x000D_
_x000D_
  var options = $.extend({},_x000D_
    $.datepicker.regional["ja"], {_x000D_
      dateFormat: "yy/mm/dd",_x000D_
      changeMonth: true,_x000D_
      changeYear: true,_x000D_
      highlightWeek: true_x000D_
    }_x000D_
  );_x000D_
_x000D_
  $("#japaneseCalendar").datepicker(options);_x000D_
});

_x000D_

#ui-datepicker-div {_x000D_
  font-size: 14px;_x000D_
}

_x000D_

<!DOCTYPE html>_x000D_
<html>_x000D_
<head>_x000D_
    <meta charset="UTF-8">_x000D_
    <link rel="stylesheet" type="text/css"_x000D_
          href="https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.12.1/themes/smoothness/jquery-ui.min.css">_x000D_
    <script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>_x000D_
    <script src="https://code.jquery.com/ui/1.12.1/jquery-ui.min.js"></script>_x000D_
    <script src="https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.11.1/i18n/jquery-ui-i18n.min.js"></script>_x000D_
</head>_x000D_
<body>_x000D_
<h3>Japanese JQuery UI Datepicker</h3>_x000D_
<input type="text" id="japaneseCalendar"/>_x000D_
_x000D_
</body>_x000D_
</html>

_x000D_

CreateProcess error=206, The filename or extension is too long when running main() method

In intellij there is an option to 'shorten command line', select 'JAR manifest' or '@argFiles' would solve the problem, basically it will put your lengthy class path into a jar file or a temp file

An object reference is required to access a non-static member

playSound is a static method in your class, but you are referring to members like audioSounds or minTime which are not declared static so they would require a SoundManager sm = new SoundManager(); to operate as sm.audioSounds or sm.minTime respectively

Solution:

public static List<AudioSource> audioSounds = new List<AudioSource>();
public static double minTime = 0.5;

PHP 7 simpleXML

I had the same problem and I'm using Ubuntu 15.10.

In my case, to solve this issue, I installed the package php7.0-xml using the Synaptic package manager, which include SimpleXml. So, after restart my Apache server, my problem was solved. This package came in the Debian version and you can find it here: https://packages.debian.org/sid/php7.0-xml.

Convert SQL Server result set into string

Both answers are valid, but don't forget to initializate the value of the variable, by default is NULL and with T-SQL:

NULL + "Any text" => NULL

It's a very common mistake, don't forget it!

Also is good idea to use ISNULL function:

SELECT @result = @result + ISNULL(StudentId + ',', '') FROM Student

AngularJS - Animate ng-view transitions

1.Install angular-animate

2.Add the animation effect to the class ng-enter for page entering animation and the class ng-leave for page exiting animation

for reference: this page has a free resource on angular view transition https://e21code.herokuapp.com/angularjs-page-transition/

Array Size (Length) in C#

yourArray.Length :)

How to subtract a day from a date?

Just to Elaborate an alternate method and a Use case for which it is helpful:

Subtract 1 day from current datetime:

from datetime import datetime, timedelta
print datetime.now() + timedelta(days=-1)  # Here, I am adding a negative timedelta

Useful in the Case, If you want to add 5 days and subtract 5 hours from current datetime. i.e. What is the Datetime 5 days from now but 5 hours less ?

from datetime import datetime, timedelta
print datetime.now() + timedelta(days=5, hours=-5)

It can similarly be used with other parameters e.g. seconds, weeks etc

How to use workbook.saveas with automatic Overwrite

To split the difference of opinion

I prefer:

   xls.DisplayAlerts = False    
   wb.SaveAs fullFilePath, AccessMode:=xlExclusive, ConflictResolution:=xlLocalSessionChanges
   xls.DisplayAlerts = True

Clearing localStorage in javascript?

If you want to remove a specific Item or variable from the user's local storage, you can use

localStorage.removeItem("name of localStorage variable you want to remove");

Force "portrait" orientation mode

Note that

android:screenOrientation="portrait"     
android:configChanges="orientation|keyboardHidden"

is added in the manifest file - where the activity is defined.

WaitAll vs WhenAll

What do they do:

Internally both do the same thing.

What's the difference:

WaitAll is a blocking call
WhenAll - not - code will continue executing

Use which when:

WaitAll when cannot continue without having the result
WhenAll when what just to be notified, not blocked

How to count digits, letters, spaces for a string in Python?

sample = ("Python 3.2 is very easy") #sample string  
letters = 0  # initiating the count of letters to 0
numeric = 0  # initiating the count of numbers to 0

        for i in sample:  
            if i.isdigit():      
                numeric +=1      
            elif i.isalpha():    
                letters +=1    
            else:    
               pass  
letters  
numeric

How to reset par(mfrow) in R

You can reset the mfrow parameter

par(mfrow=c(1,1))

How to install mod_ssl for Apache httpd?

Are any other LoadModule commands referencing modules in the /usr/lib/httpd/modules folder? If so, you should be fine just adding LoadModule ssl_module /usr/lib/httpd/modules/mod_ssl.so to your conf file.

Otherwise, you'll want to copy the mod_ssl.so file to whatever directory the other modules are being loaded from and reference it there.

What JSON library to use in Scala?

Unfortunately writing a JSON library is the Scala community's version of coding a todo list app.

There are quite a variety of alternatives. I list them in no particular order, with notes:

parsing.json.JSON - Warning this library is available only up to Scala version 2.9.x (removed in newer versions)
spray-json - Extracted from the Spray project
Jerkson ± - Warning a nice library (built on top of Java Jackson) but now abandonware. If you are going to use this, probably follow the Scalding project's example and use the backchat.io fork
sjson - By Debasish Ghosh
lift-json - Can be used separately from the Lift project
json4s § ± - An extraction from lift-json, which is attempting to create a standard JSON AST which other JSON libraries can use. Includes a Jackson-backed implementation
Argonaut § - A FP-oriented JSON library for Scala, from the people behind Scalaz
play-json ± - Now available standalone, see this answer for details
dijon - A handy, safe and efficient JSON library, uses jsoniter-scala under hood.
sonofjson - JSON library aiming for a super-simple API
Jawn - JSON library by Erik Osheim aiming for Jackson-or-faster speed
Rapture JSON ± - a JSON front-end which can use 2, 4, 5, 6, 7, 11 or Jackson as back-ends
circe - fork of Argonaut built on top of cats instead of scalaz
jsoniter-scala - Scala macros for compile-time generation of ultra-fast JSON codecs
jackson-module-scala - Add-on module for Jackson to support Scala-specific datatypes
borer - Efficient CBOR and JSON (de)serialization in Scala

= has not fixed security vulnerabilities, § = has Scalaz integration, ± = supports interop with Jackson JsonNode

In Snowplow we use json4s with the Jackson back-end; we've had good experiences with Argonaut too.

Why are you not able to declare a class as static in Java?

Everything we code in java goes into a class. Whenever we run a class JVM instantiates an object. JVM can create a number of objects, by definition Static means you have the same set of copy to all objects.

So, if Java would have allowed the top class to be static whenever you run a program it creates an Object and keeps overriding on to the same Memory Location.

If You are just replacing the object every time you run it whats the point of creating it?

So that is the reason Java got rid of the static for top-Level Class.

There might be more concrete reasons but this made much logical sense to me.

Cannot deserialize the current JSON array (e.g. [1,2,3])

That's because the json you're getting is an array of your RootObject class, rather than a single instance, change your DeserialiseObject<RootObject> to be something like DeserialiseObject<RootObject[]> (un-tested).

You'll then have to either change your method to return a collection of RootObject or do some further processing on the deserialised object to return a single instance.

If you look at a formatted version of the response you provided:

[
   {
      "id":3636,
      "is_default":true,
      "name":"Unit",
      "quantity":1,
      "stock":"100000.00",
      "unit_cost":"0"
   },
   {
      "id":4592,
      "is_default":false,
      "name":"Bundle",
      "quantity":5,
      "stock":"100000.00",
      "unit_cost":"0"
   }
]

You can see two instances in there.

Why does .NET foreach loop throw NullRefException when collection is null?

Another extension method to work around this:

public static void ForEach<T>(this IEnumerable<T> items, Action<T> action)
{
    if(items == null) return;
    foreach (var item in items) action(item);
}

Consume in several ways:

(1) with a method that accepts T:

returnArray.ForEach(Console.WriteLine);

(2) with an expression:

returnArray.ForEach(i => UpdateStatus(string.Format("{0}% complete", i)));

(3) with a multiline anonymous method

int toCompare = 10;
returnArray.ForEach(i =>
{
    var thisInt = i;
    var next = i++;
    if(next > 10) Console.WriteLine("Match: {0}", i);
});

Store select query's output in one array in postgres

I had exactly the same problem. Just one more working modification of the solution given by Denis (the type must be specified):

SELECT ARRAY(
SELECT column_name::text
FROM information_schema.columns
WHERE table_name='aean'
)

Using numpy to build an array of all combinations of two arrays

For a pure numpy implementation of Cartesian product of 1D arrays (or flat python lists), just use meshgrid(), roll the axes with transpose(), and reshape to the desired ouput:

 def cartprod(*arrays):
     N = len(arrays)
     return transpose(meshgrid(*arrays, indexing='ij'), 
                      roll(arange(N + 1), -1)).reshape(-1, N)

Note this has the convention of last axis changing fastest ("C style" or "row-major").

In [88]: cartprod([1,2,3], [4,8], [100, 200, 300, 400], [-5, -4])
Out[88]: 
array([[  1,   4, 100,  -5],
       [  1,   4, 100,  -4],
       [  1,   4, 200,  -5],
       [  1,   4, 200,  -4],
       [  1,   4, 300,  -5],
       [  1,   4, 300,  -4],
       [  1,   4, 400,  -5],
       [  1,   4, 400,  -4],
       [  1,   8, 100,  -5],
       [  1,   8, 100,  -4],
       [  1,   8, 200,  -5],
       [  1,   8, 200,  -4],
       [  1,   8, 300,  -5],
       [  1,   8, 300,  -4],
       [  1,   8, 400,  -5],
       [  1,   8, 400,  -4],
       [  2,   4, 100,  -5],
       [  2,   4, 100,  -4],
       [  2,   4, 200,  -5],
       [  2,   4, 200,  -4],
       [  2,   4, 300,  -5],
       [  2,   4, 300,  -4],
       [  2,   4, 400,  -5],
       [  2,   4, 400,  -4],
       [  2,   8, 100,  -5],
       [  2,   8, 100,  -4],
       [  2,   8, 200,  -5],
       [  2,   8, 200,  -4],
       [  2,   8, 300,  -5],
       [  2,   8, 300,  -4],
       [  2,   8, 400,  -5],
       [  2,   8, 400,  -4],
       [  3,   4, 100,  -5],
       [  3,   4, 100,  -4],
       [  3,   4, 200,  -5],
       [  3,   4, 200,  -4],
       [  3,   4, 300,  -5],
       [  3,   4, 300,  -4],
       [  3,   4, 400,  -5],
       [  3,   4, 400,  -4],
       [  3,   8, 100,  -5],
       [  3,   8, 100,  -4],
       [  3,   8, 200,  -5],
       [  3,   8, 200,  -4],
       [  3,   8, 300,  -5],
       [  3,   8, 300,  -4],
       [  3,   8, 400,  -5],
       [  3,   8, 400,  -4]])

If you want to change the first axis fastest ("FORTRAN style" or "column-major"), just change the order parameter of reshape() like this: reshape((-1, N), order='F')

Class constants in python

Since Horse is a subclass of Animal, you can just change

print(Animal.SIZES[1])

with

print(self.SIZES[1])

Still, you need to remember that SIZES[1] means "big", so probably you could improve your code by doing something like:

class Animal:
    SIZE_HUGE="Huge"
    SIZE_BIG="Big"
    SIZE_MEDIUM="Medium"
    SIZE_SMALL="Small"

class Horse(Animal):
    def printSize(self):
        print(self.SIZE_BIG)

Alternatively, you could create intermediate classes: HugeAnimal, BigAnimal, and so on. That would be especially helpful if each animal class will contain different logic.

must declare a named package eclipse because this compilation unit is associated to the named module

Just delete module-info.java at your Project Explorer tab.

Pass a String from one Activity to another Activity in Android

Most likely as others have said you want to attach it to your Intent with putExtra. But I want to throw out there that depending on what your use case is, it may be better to have one activity that switches between two fragments. The data is stored in the activity and never has to be passed.

Cookies on localhost with explicit domain

I broadly agree with @Ralph Buchfelder, but here's some amplification of this, by experiment when trying to replicate a system with several subdomains (such as example.com, fr.example.com, de.example.com) on my local machine (OS X / Apache / Chrome|Firefox).

I've edited /etc/hosts to point some imaginary subdomains at 127.0.0.1:

127.0.0.1 localexample.com
127.0.0.1 fr.localexample.com
127.0.0.1 de.localexample.com

If I am working on fr.localexample.com and I leave the domain parameter out, the cookie is stored correctly for fr.localexample.com, but is not visible in the other subdomains.

If I use a domain of ".localexample.com", the cookie is stored correctly for fr.localexample.com, and is visible in other subdomains.

If I use a domain of "localexample.com", or when I was trying a domain of just "localexample" or "localhost", the cookie was not getting stored.

If I use a domain of "fr.localexample.com" or ".fr.localexample.com", the cookie is stored correctly for fr.localexample.com and is (correctly) invisible in other subdomains.

So the requirement that you need at least two dots in the domain appears to be correct, even though I can't see why it should be.

If anyone wants to try this out, here's some useful code:

<html>
<head>
<title>
Testing cookies
</title>
</head>
<body>
<?php
header('HTTP/1.0 200');
$domain = 'fr.localexample.com';    // Change this to the domain you want to test.
if (!empty($_GET['v'])) {
    $val = $_GET['v'];
    print "Setting cookie to $val<br/>";
    setcookie("mycookie", $val, time() + 48 * 3600, '/', $domain);
}
print "<pre>";
print "Cookie:<br/>";
var_dump($_COOKIE);
print "Server:<br/>";
var_dump($_SERVER);
print "</pre>";
?>
</body>
</html>

How do you plot bar charts in gnuplot?

plot "data.dat" using 2: xtic(1) with histogram

Here data.dat contains data of the form

title 1
title2 3
"long title" 5

Passing variables through handlebars partial

The accepted answer works great if you just want to use a different context in your partial. However, it doesn't let you reference any of the parent context. To pass in multiple arguments, you need to write your own helper. Here's a working helper for Handlebars 2.0.0 (the other answer works for versions <2.0.0):

Handlebars.registerHelper('renderPartial', function(partialName, options) {
    if (!partialName) {
        console.error('No partial name given.');
        return '';
    }
    var partial = Handlebars.partials[partialName];
    if (!partial) {
        console.error('Couldnt find the compiled partial: ' + partialName);
        return '';
    }
    return new Handlebars.SafeString( partial(options.hash) );
});

Then in your template, you can do something like:

{{renderPartial 'myPartialName' foo=this bar=../bar}}

And in your partial, you'll be able to access those values as context like:

<div id={{bar.id}}>{{foo}}</div>

Check for file exists or not in sql server?

Create a function like so:

CREATE FUNCTION dbo.fn_FileExists(@path varchar(512))
RETURNS BIT
AS
BEGIN
     DECLARE @result INT
     EXEC master.dbo.xp_fileexist @path, @result OUTPUT
     RETURN cast(@result as bit)
END;
GO

Edit your table and add a computed column (IsExists BIT). Set the expression to:

dbo.fn_FileExists(filepath)

Then just select:

SELECT * FROM dbo.MyTable where IsExists = 1

Update:

To use the function outside a computed column:

select id, filename, dbo.fn_FileExists(filename) as IsExists
from dbo.MyTable

Update:

If the function returns 0 for a known file, then there is likely a permissions issue. Make sure the SQL Server's account has sufficient permissions to access the folder and files. Read-only should be enough.

And YES, by default, the 'NETWORK SERVICE' account will not have sufficient right into most folders. Right click on the folder in question and select 'Properties', then click on the 'Security' tab. Click 'Edit' and add 'Network Service'. Click 'Apply' and retest.

"PKIX path building failed" and "unable to find valid certification path to requested target"

i have the same problem on ubuntu 15.10. Please try download plugin locally e.g. https://github.com/lmenezes/elasticsearch-kopf/archive/master.zip and install with this command:

sudo /usr/share/elasticsearch/bin/plugin install file:/home/dev/Downloads/elasticsearch-kopf-master.zip

Path maybe different depending on your environment.

Regards.

Mailbox unavailable. The server response was: 5.7.1 Unable to relay for [email protected]

If you have Exchange 2010:

(In my case, the error message didn't contain " for [email protected]")

This shows how to add a receive connector: http://exchangeserverpro.com/how-to-configure-a-relay-connector-for-exchange-server-2010/

But I also needed to perform a step found here: http://recover-email.blogspot.com.au/2013/12/how-to-solve-exchange-smtp-server-error.html

Go to Exchange Management Shell and run the command

Get-ReceiveConnector "JiraTest" | Add-ADPermission -User "NT AUTHORITY\ANONYMOUS LOGON" -ExtendedRights "ms-Exch-SMTP-Accept-Any-Recipient"

While working on this, I ran the following on the affected server's PowerShell console until the error went away:

Send-MailMessage -From "[email protected]" -To "[email protected]" -Subject "Test Email" -Body "This is a test"

Objective-C : BOOL vs bool

As mentioned above BOOL could be an unsigned char type depending on your architecture, while bool is of type int. A simple experiment will show the difference why BOOL and bool can behave differently:

bool ansicBool = 64;
if(ansicBool != true) printf("This will not print\n");

printf("Any given vlaue other than 0 to ansicBool is evaluated to %i\n", ansicBool);

BOOL objcBOOL = 64;
if(objcBOOL != YES) printf("This might print depnding on your architecture\n");

printf("BOOL will keep whatever value you assign it: %i\n", objcBOOL);

if(!objcBOOL) printf("This will not print\n");

printf("! operator will zero objcBOOL %i\n", !objcBOOL);

if(!!objcBOOL) printf("!! will evaluate objcBOOL value to %i\n", !!objcBOOL);

To your surprise if(objcBOOL != YES) will evaluates to 1 by the compiler, since YES is actually the character code 1, and in the eyes of compiler, character code 64 is of course not equal to character code 1 thus the if statement will evaluate to YES/true/1 and the following line will run. However since a none zero bool type always evaluates to the integer value of 1, the above issue will not effect your code. Below are some good tips if you want to use the Objective-C BOOL type vs the ANSI C bool type:

Always assign the YES or NO value and nothing else.
Convert BOOL types by using double not !! operator to avoid unexpected results.
When checking for YES use if(!myBool) instead of if(myBool != YES) it is much cleaner to use the not ! operator and gives the expected result.

Copy array by value

Some of mentioned methods work well when working with simple data types like number or string, but when the array contains other objects these methods fail. When we try to pass any object from one array to another it is passed as a reference, not the object.

Add the following code in your JavaScript file:

Object.prototype.clone = function() {
    var newObj = (this instanceof Array) ? [] : {};
    for (i in this) {
        if (i == 'clone') 
            continue;
        if (this[i] && typeof this[i] == "object") {
            newObj[i] = this[i].clone();
        } 
        else 
            newObj[i] = this[i]
    } return newObj;
};

And simply use

var arr1 = ['val_1','val_2','val_3'];
var arr2 = arr1.clone()

It will work.

Purpose of Unions in C and C++

As you say, this is strictly undefined behaviour, though it will "work" on many platforms. The real reason for using unions is to create variant records.

union A {
   int i;
   double d;
};

A a[10];    // records in "a" can be either ints or doubles 
a[0].i = 42;
a[1].d = 1.23;

Of course, you also need some sort of discriminator to say what the variant actually contains. And note that in C++ unions are not much use because they can only contain POD types - effectively those without constructors and destructors.

Using BigDecimal to work with currencies

Or, wait for JSR-354. Java Money and Currency API coming soon!

Python-equivalent of short-form "if" in C++

a = '123' if b else '456'

How to vertically align text in input type="text"?

Use padding to fake it since vertical-align doesn't work on text inputs.

jsFiddle example

CSS

.date-input {     
    width: 145px;
    padding-top: 80px;
}?

How can strip whitespaces in PHP's variable?

You can do it by using ereg_replace

 $str = 'This Is New Method Ever';
 $newstr = ereg_replace([[:space:]])+', '',  trim($str)):
 echo $newstr
 // Result - ThisIsNewMethodEver

Jersey client: How to add a list as query parameter

If you are sending anything other than simple strings I would recommend using a POST with an appropriate request body, or passing the entire list as an appropriately encoded JSON string. However, with simple strings you just need to append each value to the request URL appropriately and Jersey will deserialize it for you. So given the following example endpoint:

@Path("/service/echo") public class MyServiceImpl {
    public MyServiceImpl() {
        super();
    }

    @GET
    @Path("/withlist")
    @Produces(MediaType.TEXT_PLAIN)
    public Response echoInputList(@QueryParam("list") final List<String> inputList) {
        return Response.ok(inputList).build();
    }
}

Your client would send a request corresponding to:

GET http://example.com/services/echo?list=Hello&list=Stay&list=Goodbye

Which would result in inputList being deserialized to contain the values 'Hello', 'Stay' and 'Goodbye'

How to load a text file into a Hive table stored as sequence files

The simple way is to create table as textfile and move the file to the appropriate location

CREATE EXTERNAL TABLE mytable(col1 string, col2 string)
row format delimited fields terminated by '|' stored as textfile;

Copy the file to the HDFS Location where table is created.
Hope this helps!!!

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

You can also use the NSString class methods which will also create an autoreleased instance and have more options like string formatting:

NSString *myString = [NSString stringWithString:@"abc"];
NSString *myString = [NSString stringWithFormat:@"abc %d efg", 42];

gcc-arm-linux-gnueabi command not found

fixed, using:

sudo apt-get install gcc-arm*

Alternate background colors for list items

You can achieve this by adding alternating style classes to each list item

<ul>
    <li class="odd"><a href="link">Link 1</a></li>
    <li><a href="link">Link 2</a></li>
    <li class="odd"><a href="link">Link 2</a></li>
    <li><a href="link">Link 2</a></li>
</ul>

And then styling it like

li { backgorund:white; }
li.odd { background:silver; }

You can further automate this process with javascript (jQuery example below)

$(document).ready(function() {
  $('table tbody tr:odd').addClass('odd');
});

Single quotes vs. double quotes in Python

I'm with Will:

Double quotes for text
Single quotes for anything that behaves like an identifier
Double quoted raw string literals for regexps
Tripled double quotes for docstrings

I'll stick with that even if it means a lot of escaping.

I get the most value out of single quoted identifiers standing out because of the quotes. The rest of the practices are there just to give those single quoted identifiers some standing room.

How to specify test directory for mocha?

Don't use the -g or --grep option, that pattern operates on the name of the test inside of it(), not the filesystem. The current documentation is misleading and/or outright wrong concerning this. To limit the entire command to a portion of the filesystem, you can pass a pattern as the last argument (its not a flag).

For example, this command will set your reporter to spec but will only test js files immediately inside of the server-test directory:

mocha --reporter spec server-test/*.js

This command will do the same as above, plus it will only run the test cases where the it() string/definition of a test begins with "Fnord:":

mocha --reporter spec --grep "Fnord:" server-test/*.js

PHP include relative path

function relativepath($to){
    $a=explode("/",$_SERVER["PHP_SELF"] );
    $index= array_search("$to",$a);
    $str=""; 
    for ($i = 0; $i < count($a)-$index-2; $i++) {
        $str.= "../";
    }
    return $str;
    }

Here is the best solution i made about that, you just need to specify at which level you want to stop, but the problem is that you have to use this folder name one time.

How do I handle the window close event in Tkinter?

Depending on the Tkinter activity, and especially when using Tkinter.after, stopping this activity with destroy() -- even by using protocol(), a button, etc. -- will disturb this activity ("while executing" error) rather than just terminate it. The best solution in almost every case is to use a flag. Here is a simple, silly example of how to use it (although I am certain that most of you don't need it! :)

from Tkinter import *

def close_window():
  global running
  running = False  # turn off while loop
  print( "Window closed")

root = Tk()
root.protocol("WM_DELETE_WINDOW", close_window)
cv = Canvas(root, width=200, height=200)
cv.pack()

running = True;
# This is an endless loop stopped only by setting 'running' to 'False'
while running: 
  for i in range(200): 
    if not running: 
        break
    cv.create_oval(i, i, i+1, i+1)
    root.update()

This terminates graphics activity nicely. You only need to check running at the right place(s).

Regex to validate date format dd/mm/yyyy

Another answer which validates day (dd) depending upon the month (mm) and the year (yyyy) (i.e., also validates 29th Feb in leap years) and allows years ranging from 0001 to 9999 (0000 in a invalid year according to the Gregorian calendar)

^(?:(?:(?:0[1-9]|[12]\d|3[01])/(?:0[13578]|1[02])|(?:0[1-9]|[12]\d|30)/(?:0[469]|11)|(?:0[1-9]|1\d|2[0-8])/02)/(?!0000)\d{4}|(?:(?:0[1-9]|[12]\d)/02/(?:(?!0000)(?:[02468][048]|[13579][26])00|(?!..00)\d{2}(?:[02468][048]|[13579][26]))))$

What is the most efficient way to store tags in a database?

One item is going to have many tags. And one tag will belong to many items. This implies to me that you'll quite possibly need an intermediary table to overcome the many-to-many obstacle.

Something like:

Table: Items
Columns: Item_ID, Item_Title, Content

Table: Tags
Columns: Tag_ID, Tag_Title

Table: Items_Tags
Columns: Item_ID, Tag_ID

It might be that your web app is very very popular and need de-normalizing down the road, but it's pointless muddying the waters too early.

How can you tell when a layout has been drawn?

When onMeasure is called the view gets its measured width/height. After this, you can call layout.getMeasuredHeight().

Return list from async/await method

Instead of doing all these, one can simply use ".Result" to get the result from a particular task.

eg: List list = GetListAsync().Result;

Which as per the definition => Gets the result value of this Task < TResult >

Open new Terminal Tab from command line (Mac OS X)

Here's how it's done by bash_it:

function tab() {
  osascript 2>/dev/null <<EOF
    tell application "System Events"
      tell process "Terminal" to keystroke "t" using command down
    end
    tell application "Terminal"
      activate
      do script with command "cd \"$PWD\"; $*" in window 1
    end tell
EOF
}

After adding this to your .bash_profile, you'd use the tab command to open the current working directory in a new tab.

See: https://github.com/revans/bash-it/blob/master/plugins/available/osx.plugin.bash#L3

Import Maven dependencies in IntelliJ IDEA

IntelliJ should download and add all your dependencies to the project's classpath automatically as long as your POM is compliant and all the dependencies are available.

When importing Maven projects into IntelliJ an information box usually comes up asking you if you want to configure Auto-Import for Maven projects. That means that if you make any changes to your POM those changes will be loaded automatically.

You can enable such feature going to File > Settings > Maven > Importing, there is a checkbox that says "Import Maven projects automatically".

If that doesn't help, then I would suggest to make a full clean-up and start again:

Close your project window (and IntelliJ) and remove all *.iml files and all .idea folders (there should be one per module)
Run mvn clean install from the command line
Re-import the project into IntelliJ and pay attention when it asks you to enable auto-import

IntelliJ 2016 Update:

The Import Maven Projects automatically setting has been moved to Build, Execution, Deployment > Build Tools > Maven > Importing in your IntelliJ preferences.

ASP.NET MVC Html.ValidationSummary(true) does not display model errors

I believe the way the ValidationSummary flag works is it will only display ModelErrors for string.empty as the key. Otherwise it is assumed it is a property error. The custom error you're adding has the key 'error' so it will not display in when you call ValidationSummary(true). You need to add your custom error message with an empty key like this:

ModelState.AddModelError(string.Empty, ex.Message);

Convert String[] to comma separated string in java

In java 8 for none string array and none primitive object (Long, Integer, ...)

List<Long> ids = Arrays.asList(1l, 2l,3l);
ids.stream().map(String::valueOf).collect(Collectors.joining(","))))

In java 8 for specific field of an objets array (example a car with 2 fields color and speed)

List<Car> cars= Cars.asList(car1, cars2,car3);
    cars.stream().map(Car::getColor).collect(Collectors.joining(","))))

Combine map with valueOf for none String field of an array of objects

Bootstrap modal opening on page load

Use a document.ready() event around your call.

$(document).ready(function () {

    $('#memberModal').modal('show');

});

jsFiddle updated - http://jsfiddle.net/uvnggL8w/1/

How to show loading spinner in jQuery?

If you plan to use a loader everytime you make a server request, you can use the following pattern.

 jTarget.ajaxloader(); // (re)start the loader
 $.post('/libs/jajaxloader/demo/service/service.php', function (content) {
     jTarget.append(content); // or do something with the content
 })
 .always(function () {
     jTarget.ajaxloader("stop");
 });

This code in particular uses the jajaxloader plugin (which I just created)

https://github.com/lingtalfi/JAjaxLoader/

Implementing multiple interfaces with Java - is there a way to delegate?

Unfortunately: NO.

We're all eagerly awaiting the Java support for extension methods

How to rollback or commit a transaction in SQL Server

The good news is a transaction in SQL Server can span multiple batches (each exec is treated as a separate batch.)

You can wrap your EXEC statements in a BEGIN TRANSACTION and COMMIT but you'll need to go a step further and rollback if any errors occur.

Ideally you'd want something like this:

BEGIN TRY
    BEGIN TRANSACTION 
        exec( @sqlHeader)
        exec(@sqlTotals)
        exec(@sqlLine)
    COMMIT
END TRY
BEGIN CATCH

    IF @@TRANCOUNT > 0
        ROLLBACK
END CATCH

The BEGIN TRANSACTION and COMMIT I believe you are already familiar with. The BEGIN TRY and BEGIN CATCH blocks are basically there to catch and handle any errors that occur. If any of your EXEC statements raise an error, the code execution will jump to the CATCH block.

Your existing SQL building code should be outside the transaction (above) as you always want to keep your transactions as short as possible.

What is future in Python used for and how/when to use it, and how it works

It can be used to use features which will appear in newer versions while having an older release of Python.

For example

>>> from __future__ import print_function

will allow you to use print as a function:

>>> print('# of entries', len(dictionary), file=sys.stderr)

How to convert password into md5 in jquery?

Get the field value through the id and send with ajax

var field = $("#field").val();
$.ajax({
    type: "POST",
    url: "db.php",
    data: {variable_name:field},
    async:false,
    dataType:"json",
    success: function(response) {
       alert(response);
    }
 });

At db.php file get the variable name

$variable_name = $_GET['variable_name'];
mysql_query("SELECT password FROM table_name WHERE password='".md5($variable_name)."'");

Swift days between two NSDates

Swift 5. Thanks to Emin Bugra Saral above for the startOfDay suggestion.

extension Date {
    
    func daysBetween(date: Date) -> Int {
        return Date.daysBetween(start: self, end: date)
    }
    
    static func daysBetween(start: Date, end: Date) -> Int {
        let calendar = Calendar.current
        
        // Replace the hour (time) of both dates with 00:00
        let date1 = calendar.startOfDay(for: start)
        let date2 = calendar.startOfDay(for: end)
        
        let a = calendar.dateComponents([.day], from: date1, to: date2)
        return a.value(for: .day)!
    }
}

Usage:

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
let start = dateFormatter.date(from: "2017-01-01")!
let end = dateFormatter.date(from: "2018-01-01")!

let diff = Date.daysBetween(start: start, end: end) // 365
// or
let diff = start.daysBetween(date: end) // 365

How do I create delegates in Objective-C?

Let's start with an example , if we buy a product online ,it goes through process like shipping/delivery handled by different teams.So if shipping gets completed ,shipping team should notify delivery team & it should be one to one communication as broadcasting this information would be overhead for other people / vendor might want to pass this information only to required people.

So if we think in terms of our app, an event can be an online order & different teams can be like multiple views.

Here is code consider ShippingView as Shipping team & DeliveryView as delivery team :

//Declare the protocol with functions having info which needs to be communicated
protocol ShippingDelegate : class {
    func productShipped(productID : String)
}
//shippingView which shows shipping status of products
class ShippingView : UIView
{

    weak var delegate:ShippingDelegate?
    var productID : String

    @IBAction func checkShippingStatus(sender: UIButton)
    {
        // if product is shipped
        delegate?.productShipped(productID: productID)
    }
}
//Delivery view which shows delivery status & tracking info
class DeliveryView: UIView,ShippingDelegate
{
    func productShipped(productID : String)
    {
        // update status on view & perform delivery
    }
}

//Main page on app which has both views & shows updated info on product whole status
class ProductViewController : UIViewController
{
    var shippingView : ShippingView
    var deliveryView : DeliveryView

    override func viewDidLoad() {
        super.viewDidLoad()
        // as we want to update shipping info on delivery view, so assign delegate to delivery object
        // whenever shipping status gets updated it will call productShipped method in DeliveryView & update UI.
        shippingView.delegate = deliveryView
        //
    }
}

Difference between array_push() and $array[] =

The difference is in the line below to "because in that way there is no overhead of calling a function."

array_push() will raise a warning if the first argument is not an array. This differs from the $var[] behaviour where a new array is created.

Adding options to select with javascript

None of the above solutions worked for me. Append method didn't give error when i tried but it didn't solve my problem. In the end i solved my problem with data property of select2. I used json and got the array and then give it in select2 element initialize. For more detail you can see my answer at below post.

https://stackoverflow.com/a/41297283/4928277

How to read pickle file?

Pickle serializes a single object at a time, and reads back a single object - the pickled data is recorded in sequence on the file.

If you simply do pickle.load you should be reading the first object serialized into the file (not the last one as you've written).

After unserializing the first object, the file-pointer is at the beggining of the next object - if you simply call pickle.load again, it will read that next object - do that until the end of the file.

objects = []
with (open("myfile", "rb")) as openfile:
    while True:
        try:
            objects.append(pickle.load(openfile))
        except EOFError:
            break

Moving all files from one directory to another using Python

import shutil 
import os 
import logging

source = '/var/spools/asterisk/monitor' 
dest1 = '/tmp/'


files = os.listdir(source)

for f in files:
        shutil.move(source+f, dest1)

logging.basicConfig(filename='app.log', filemode='w', format='%(name)s
- %(levelname)s - %(message)s')

logging.info('directories moved')

A little bit cooked code with log feature. You can also configure this to run at some period of time using crontab.

* */1 * * * python /home/yourprogram.py > /dev/null 2>&1

runs every hour! cheers

Click to call html

tl;dr What to do in modern (2018) times? Assume tel: is supported, use it and forget about anything else.

The tel: URI scheme RFC5431 (as well as sms: but also feed:, maps:, youtube: and others) is handled by protocol handlers (as mailto: and http: are).

They're unrelated to HTML5 specification (it has been out there from 90s and documented first time back in 2k with RFC2806) then you can't check for their support using tools as modernizr. A protocol handler may be installed by an application (for example Skype installs a callto: protocol handler with same meaning and behaviour of tel: but it's not a standard), natively supported by browser or installed (with some limitations) by website itself.

What HTML5 added is support for installing custom web based protocol handlers (with registerProtocolHandler() and related functions) simplifying also the check for their support through isProtocolHandlerRegistered() function.

There is some easy ways to determine if there is an handler or not:" How to detect browser's protocol handlers?).

In general what I suggest is:

If you're running on a mobile device then you can safely assume tel: is supported (yes, it's not true for very old devices but IMO you can ignore them).
If JS isn't active then do nothing.
If you're running on desktop browsers then you can use one of the techniques in the linked post to determine if it's supported.
If tel: isn't supported then change links to use callto: and repeat check desctibed in 3.
If tel: and callto: aren't supported (or - in a desktop browser - you can't detect their support) then simply remove that link replacing URL in href with javascript:void(0) and (if number isn't repeated in text span) putting, telephone number in title. Here HTML5 microdata won't help users (just search engines). Note that newer versions of Skype handle both callto: and tel:.

Please note that (at least on latest Windows versions) there is always a - fake - registered protocol handler called App Picker (that annoying window that let you choose with which application you want to open an unknown file). This may vanish your tests so if you don't want to handle Windows environment as a special case you can simplify this process as:

If you're running on a mobile device then assume tel: is supported.
If you're running on desktop ~~then replace tel: with callto:.~~ then drop tel: or leave it as is (assuming there are good chances Skype is installed).

What's an object file in C?

An object file is just what you get when you compile one (or several) source file(s).

It can be either a fully completed executable or library, or intermediate files.

The object files typically contain native code, linker information, debugging symbols and so forth.

How to let an ASMX file output JSON

Are you calling the web service from client script or on the server side?

You may find sending a content type header to the server will help, e.g.

'application/json; charset=utf-8'

On the client side, I use prototype client side library and there is a contentType parameter when making an Ajax call where you can specify this. I think jQuery has a getJSON method.

nodeJS - How to create and read session with express

I forgot to tell a bug when i use I use req.session.email = req.param('email'), the server error says cannot sett property email of undefined.

The reason of this error is a wrong order of app.use. You must configure express in this order:

app.use(express.cookieParser());
app.use(express.session({ secret: sessionVal }));
app.use(app.route);

How to execute a shell script from C in Linux?

If you need more fine-grade control, you can also go the fork pipe exec route. This will allow your application to retrieve the data outputted from the shell script.

How should I tackle --secure-file-priv in MySQL?

On Ubuntu 14 and Mysql 5.5.53 this setting seems to be enabled by default. To disable it you need to add secure-file-priv = "" to your my.cnf file under the mysqld config group. eg:-

[mysqld]
secure-file-priv = ""

How do I get the height of a div's full content with jQuery?

You can get it with .outerHeight().

Sometimes, it will return 0. For the best results, you can call it in your div's ready event.

To be safe, you should not set the height of the div to x. You can keep its height auto to get content populated properly with the correct height.

$('#x').ready( function(){
// alerts the height in pixels
alert($('#x').outerHeight());
})

You can find a detailed post here.

Construct pandas DataFrame from list of tuples of (row,col,values)

This is what I expected to see when I came to this question:

#!/usr/bin/env python

import pandas as pd


df = pd.DataFrame([(1, 2, 3, 4),
                   (5, 6, 7, 8),
                   (9, 0, 1, 2),
                   (3, 4, 5, 6)],
                  columns=list('abcd'),
                  index=['India', 'France', 'England', 'Germany'])
print(df)

gives

         a  b  c  d
India    1  2  3  4
France   5  6  7  8
England  9  0  1  2
Germany  3  4  5  6

Xcode couldn't find any provisioning profiles matching

What fixed it for me was plugging my iPhone and allowing it as a simulator destination. Doing so required my to register my iPhone in Apple Dev account and once that was done and I ran my project from Xcode on my iPhone everything fixed itself.

Connect your iPhone to your Mac
Xcode>Window>Devices & Simulators
Add new under Devices and make sure "show are run destination" is ticked
Build project and run it on your iPhone

Remove menubar from Electron app

You can use w.setMenu(null) or set frame: false (this also removes buttons for close, minimize and maximize options) on your window. See setMenu() or BrowserWindow(). Also check this thread

Electron now has win.removeMenu() (added in v5.0.0), to remove application menus instead of using win.setMenu(null).

Electron 7.1.x seems to have a bug where win.removeMenu() doesn't work. The only workaround is to use Menu.setApplicationMenu(null)

Can you split a stream into two streams?

I stumbled across this question to my self and I feel that a forked stream has some use cases that could prove valid. I wrote the code below as a consumer so that it does not do anything but you could apply it to functions and anything else you might come across.

class PredicateSplitterConsumer<T> implements Consumer<T>
{
  private Predicate<T> predicate;
  private Consumer<T>  positiveConsumer;
  private Consumer<T>  negativeConsumer;

  public PredicateSplitterConsumer(Predicate<T> predicate, Consumer<T> positive, Consumer<T> negative)
  {
    this.predicate = predicate;
    this.positiveConsumer = positive;
    this.negativeConsumer = negative;
  }

  @Override
  public void accept(T t)
  {
    if (predicate.test(t))
    {
      positiveConsumer.accept(t);
    }
    else
    {
      negativeConsumer.accept(t);
    }
  }
}

Now your code implementation could be something like this:

personsArray.forEach(
        new PredicateSplitterConsumer<>(
            person -> person.getDateOfBirth().isPresent(),
            person -> System.out.println(person.getName()),
            person -> System.out.println(person.getName() + " does not have Date of birth")));

How to launch jQuery Fancybox on page load?

Alex's answer is great. but It is importanting to note that that calls the default fancybox style. If you have your own custom rules, you should just call .trigger click on that specific anchor

$(document).ready(function() {
$("#hidden_link").fancybox({ 
    'padding':          0,
    'cyclic':       true,
    'width':        625,
    'height':       350,
    'padding':      0, 
    'margin':      0, 
    'speedIn':      300,
    'speedOut':     300,
    'transitionIn': 'elastic',
    'transitionOut': 'elastic',
    'easingIn':     'swing',
    'easingOut':    'swing',
    'titleShow' : false
}); 
    $("#hidden_link").trigger('click');
});

Creating a ZIP archive in memory using System.IO.Compression

This is the way to convert a entity to XML File and then compress it:

private  void downloadFile(EntityXML xml) {

string nameDownloadXml = "File_1.xml";
string nameDownloadZip = "File_1.zip";

var serializer = new XmlSerializer(typeof(EntityXML));

Response.Clear();
Response.ClearContent();
Response.ClearHeaders();
Response.AddHeader("content-disposition", "attachment;filename=" + nameDownloadZip);

using (var memoryStream = new MemoryStream())
{
    using (var archive = new ZipArchive(memoryStream, ZipArchiveMode.Create, true))
    {
        var demoFile = archive.CreateEntry(nameDownloadXml);
        using (var entryStream = demoFile.Open())
        using (StreamWriter writer = new StreamWriter(entryStream, System.Text.Encoding.UTF8))
        {
            serializer.Serialize(writer, xml);
        }
    }

    using (var fileStream = Response.OutputStream)
    {
        memoryStream.Seek(0, SeekOrigin.Begin);
        memoryStream.CopyTo(fileStream);
    }
}

Response.End();

}

How to search a Git repository by commit message?

To search the commit log (across all branches) for the given text:

git log --all --grep='Build 0051'

To search the actual content of commits through a repo's history, use:

git grep 'Build 0051' $(git rev-list --all)

to show all instances of the given text, the containing file name, and the commit sha1.

Finally, as a last resort in case your commit is dangling and not connected to history at all, you can search the reflog itself with the -g flag (short for --walk-reflogs:

git log -g --grep='Build 0051'

EDIT: if you seem to have lost your history, check the reflog as your safety net. Look for Build 0051 in one of the commits listed by

git reflog

You may have simply set your HEAD to a part of history in which the 'Build 0051' commit is not visible, or you may have actually blown it away. The git-ready reflog article may be of help.

To recover your commit from the reflog: do a git checkout of the commit you found (and optionally make a new branch or tag of it for reference)

git checkout 77b1f718d19e5cf46e2fab8405a9a0859c9c2889
# alternative, using reflog (see git-ready link provided)
# git checkout HEAD@{10}
git checkout -b build_0051 # make a new branch with the build_0051 as the tip

Twitter Bootstrap add active class to li

This did the job for me including active main dropdowns and the active childrens (thanks to 422):

$(document).ready(function () {
    var url = window.location;
    // Will only work if string in href matches with location
    $('ul.nav a[href="' + url + '"]').parent().addClass('active');

    // Will also work for relative and absolute hrefs
    $('ul.nav a').filter(function () {
        return this.href == url;
    }).parent().addClass('active').parent().parent().addClass('active');
});

How to make type="number" to positive numbers only

You can turn negative input into a positive number by the following:

_x000D_

<input type="number" onkeyup="if(this.value<0){this.value= this.value * -1}">

_x000D_

How do I revert to a previous package in Anaconda?

I know it was not available at the time, but now you could also use Anaconda navigator to install a specific version of packages in the environments tab.

Selenium -- How to wait until page is completely loaded

There are two different ways to use delay in selenium one which is most commonly in use. Please try this:

driver.manage().timeouts().implicitlyWait(20, TimeUnit.SECONDS);

second one which you can use that is simply try catch method by using that method you can get your desire result.if you want example code feel free to contact me defiantly I will provide related code

CSS: how do I create a gap between rows in a table?

Simply you can use padding-top and padding-bottom on a td element.

Unit can anything from this list:

Demo Code:

_x000D_

td_x000D_
{_x000D_
  padding-top: 10px;_x000D_
  padding-bottom: 10px;_x000D_
}

_x000D_

<table>_x000D_
  <tr>_x000D_
    <th>Firstname</th>_x000D_
    <th>Lastname</th>_x000D_
  </tr>_x000D_
  <tr>_x000D_
    <td>Peter</td>_x000D_
    <td>Griffin</td>_x000D_
  </tr>_x000D_
  <tr>_x000D_
    <td>Lois</td>_x000D_
    <td>Griffin</td>_x000D_
  </tr>_x000D_
</table>

_x000D_

Hide Utility Class Constructor : Utility classes should not have a public or default constructor

Add private constructor:

private FilePathHelper(){
    super();
}

Binding ComboBox SelectedItem using MVVM

You seem to be unnecessarily setting properties on your ComboBox. You can remove the DisplayMemberPath and SelectedValuePath properties which have different uses. It might be an idea for you to take a look at the Difference between SelectedItem, SelectedValue and SelectedValuePath post here for an explanation of these properties. Try this:

<ComboBox Name="cbxSalesPeriods"
    ItemsSource="{Binding SalesPeriods}"
    SelectedItem="{Binding SelectedSalesPeriod}"
    IsSynchronizedWithCurrentItem="True"/>

Furthermore, it is pointless using your displayPeriod property, as the WPF Framework would call the ToString method automatically for objects that it needs to display that don't have a DataTemplate set up for them explicitly.

UPDATE >>>

As I can't see all of your code, I cannot tell you what you are doing wrong. Instead, all I can do is to provide you with a complete working example of how to achieve what you want. I've removed the pointless displayPeriod property and also your SalesPeriodVO property from your class as I know nothing about it... maybe that is the cause of your problem??. Try this:

public class SalesPeriodV
{
    private int month, year;

    public int Year
    {
        get { return year; }
        set
        {
            if (year != value)
            {
                year = value;
                NotifyPropertyChanged("Year");
            }
        }
    }

    public int Month
    {
        get { return month; }
        set
        {
            if (month != value)
            {
                month = value;
                NotifyPropertyChanged("Month");
            }
        }
    }

    public override string ToString()
    {
        return String.Format("{0:D2}.{1}", Month, Year);
    }

    public virtual event PropertyChangedEventHandler PropertyChanged;
    protected virtual void NotifyPropertyChanged(params string[] propertyNames)
    {
        if (PropertyChanged != null)
        {
            foreach (string propertyName in propertyNames) PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            PropertyChanged(this, new PropertyChangedEventArgs("HasError"));
        }
    }
}

Then I added two properties into the view model:

private ObservableCollection<SalesPeriodV> salesPeriods = new ObservableCollection<SalesPeriodV>();
public ObservableCollection<SalesPeriodV> SalesPeriods
{
    get { return salesPeriods; }
    set { salesPeriods = value; NotifyPropertyChanged("SalesPeriods"); }
}
private SalesPeriodV selectedItem = new SalesPeriodV();
public SalesPeriodV SelectedItem
{
    get { return selectedItem; }
    set { selectedItem = value; NotifyPropertyChanged("SelectedItem"); }
}

Then initialised the collection with your values:

SalesPeriods.Add(new SalesPeriodV() { Month = 3, Year = 2013 } );
SalesPeriods.Add(new SalesPeriodV() { Month = 4, Year = 2013 } );

And then data bound only these two properties to a ComboBox:

<ComboBox ItemsSource="{Binding SalesPeriods}" SelectedItem="{Binding SelectedItem}" />

That's it... that's all you need for a perfectly working example. You should see that the display of the items comes from the ToString method without your displayPeriod property. Hopefully, you can work out your mistakes from this code example.

CSS getting text in one line rather than two

Add white-space: nowrap;:

.garage-title {
    clear: both;
    display: inline-block;
    overflow: hidden;
    white-space: nowrap;
}

jsFiddle

ImportError: No module named 'pygame'

go to python/scripts folder, open a command window to this path, type the following:

C:\python34\scripts> python -m pip install pygame

To test it, open python IDE and type

import pygame

print (pygame.ver)

It worked for me...

java doesn't run if structure inside of onclick listener

both your conditions are the same:

if(s < f) {     calc = f - s;     n = s; }else if(f > s){     calc =  s - f;     n = f;  }

if(s < f)

and

}else if(f > s){

are the same

change to

}else if(f < s){

python to arduino serial read & write

You shouldn't be closing the serial port in Python between writing and reading. There is a chance that the port is still closed when the Arduino responds, in which case the data will be lost.

while running:  
    # Serial write section
    setTempCar1 = 63
    setTempCar2 = 37
    setTemp1 = str(setTempCar1)
    setTemp2 = str(setTempCar2)
    print ("Python value sent: ")
    print (setTemp1)
    ard.write(setTemp1)
    time.sleep(6) # with the port open, the response will be buffered 
                  # so wait a bit longer for response here

    # Serial read section
    msg = ard.read(ard.inWaiting()) # read everything in the input buffer
    print ("Message from arduino: ")
    print (msg)

The Python Serial.read function only returns a single byte by default, so you need to either call it in a loop or wait for the data to be transmitted and then read the whole buffer.

On the Arduino side, you should consider what happens in your loop function when no data is available.

void loop()
{
  // serial read section
  while (Serial.available()) // this will be skipped if no data present, leading to
                             // the code sitting in the delay function below
  {
    delay(30);  //delay to allow buffer to fill 
    if (Serial.available() >0)
    {
      char c = Serial.read();  //gets one byte from serial buffer
      readString += c; //makes the string readString
    }
  }

Instead, wait at the start of the loop function until data arrives:

void loop()
{
  while (!Serial.available()) {} // wait for data to arrive
  // serial read section
  while (Serial.available())
  {
    // continue as before

EDIT 2

Here's what I get when interfacing with your Arduino app from Python:

>>> import serial
>>> s = serial.Serial('/dev/tty.usbmodem1411', 9600, timeout=5)
>>> s.write('2')
1
>>> s.readline()
'Arduino received: 2\r\n'

So that seems to be working fine.

In testing your Python script, it seems the problem is that the Arduino resets when you open the serial port (at least my Uno does), so you need to wait a few seconds for it to start up. You are also only reading a single line for the response, so I've fixed that in the code below also:

#!/usr/bin/python
import serial
import syslog
import time

#The following line is for serial over GPIO
port = '/dev/tty.usbmodem1411' # note I'm using Mac OS-X


ard = serial.Serial(port,9600,timeout=5)
time.sleep(2) # wait for Arduino

i = 0

while (i < 4):
    # Serial write section

    setTempCar1 = 63
    setTempCar2 = 37
    ard.flush()
    setTemp1 = str(setTempCar1)
    setTemp2 = str(setTempCar2)
    print ("Python value sent: ")
    print (setTemp1)
    ard.write(setTemp1)
    time.sleep(1) # I shortened this to match the new value in your Arduino code

    # Serial read section
    msg = ard.read(ard.inWaiting()) # read all characters in buffer
    print ("Message from arduino: ")
    print (msg)
    i = i + 1
else:
    print "Exiting"
exit()

Here's the output of the above now:

$ python ardser.py
Python value sent:
63
Message from arduino:
Arduino received: 63
Arduino sends: 1


Python value sent:
63
Message from arduino:
Arduino received: 63
Arduino sends: 1


Python value sent:
63
Message from arduino:
Arduino received: 63
Arduino sends: 1


Python value sent:
63
Message from arduino:
Arduino received: 63
Arduino sends: 1


Exiting

Java - Convert image to Base64

The line

base64String = Base64.encode(byteArray);

converts the full array (102400 bytes) to Base64, not just the number of bytes you have read. You need to pass it the numbers of bytes.

Using BETWEEN in CASE SQL statement

Take out the MONTHS from your case, and remove the brackets... like this:

CASE 
    WHEN RATE_DATE BETWEEN '2010-01-01' AND '2010-01-31' THEN 'JANUARY'
    ELSE 'NOTHING'
END AS 'MONTHS'

You can think of this as being equivalent to:

CASE TRUE
    WHEN RATE_DATE BETWEEN '2010-01-01' AND '2010-01-31' THEN 'JANUARY'
    ELSE 'NOTHING'
END AS 'MONTHS'

How do I get the file extension of a file in Java?

This particular question gave me a lot of trouble then i found a very simple solution for this problem which i'm posting here.

file.getName().toLowerCase().endsWith(".txt");

That's it.

Failed to serialize the response in Web API with Json

Use [Serializable] for class:

Example:

[Serializable]
public class UserModel {
    public string Name {get;set;}
    public string Age {get;set;}
}

It worked for me!

Best way to access web camera in Java

This has been discussed on SO multiple times. Here are a few links to get you started:

SO: Capturing image from webcam in java?

SO: What is the best method to capture images from a live video device for use by a Java-based application?

openCVF applet: http://www.colorfulwolf.com/blog/2011/07/05/accessing-the-webcam-from-inside-a-java-applet/

config: http://ganeshtiwaridotcomdotnp.blogspot.in/2011/12/opencv-javacv-eclipse-project.html

how to get the ipaddress of a virtual box running on local machine

ifconfig
ip addr show

If you used NAT for your virtual machine settings(your machine ip will be 10.0.2.15), then you have to use port forwarding to connect to machine. IP address will be 127.0.0.1

If you used bridged networking/Host only networking, then you will have separate Ip address. Use that IP address to connect virtual machine

React component not re-rendering on state change

Another oh-so-easy mistake, which was the source of the problem for me: I’d written my own shouldComponentUpdate method, which didn’t check the new state change I’d added.

Rounding SQL DateTime to midnight

Try using this.

WHERE Orders.OrderStatus = 'Shipped'  
AND Orders.ShipDate >= CONVERT(DATE, GETDATE())

Delete all rows in an HTML table

Points to note, on the Watch out for common mistakes:

If your start index is 0 (or some index from begin), then, the correct code is:

var tableHeaderRowCount = 1;
var table = document.getElementById('WRITE_YOUR_HTML_TABLE_NAME_HERE');
var rowCount = table.rows.length;
for (var i = tableHeaderRowCount; i < rowCount; i++) {
    table.deleteRow(tableHeaderRowCount);
}

NOTES

1. the argument for deleteRow is fixed
this is required since as we delete a row, the number of rows decrease.
i.e; by the time i reaches (rows.length - 1), or even before that row is already deleted, so you will have some error/exception (or a silent one).

2. the rowCount is taken before the for loop starts since as we delete the "table.rows.length" will keep on changing, so again you have some issue, that only odd or even rows only gets deleted.

Hope that helps.

Check if a value is in an array or not with Excel VBA

You want to check whether Examples exists in Range("A1").Value If it fails then to check Example right? I think mycode will work perfect. Please check.

Sub test()
Dim string1 As String, string2 As String
string1 = "Examples"
string2 = "Example"
If InStr(1, Range("A1").Value, string1) > 0 Then
    x = 1
ElseIf InStr(1, Range("A1").Value, string2) > 0 Then
    x = 2
End If

End Sub

how to avoid a new line with p tag?

Use the display: inline CSS property.

Ideal: In the stylesheet:

#container p { display: inline }

Bad/Extreme situation: Inline:

<p style="display:inline">...</p>

How to comment multiple lines with space or indent

I was able to achieve the desired result by using Alt + Shift + up/down and then typing the desired comment characters and additional character.

Hive insert query like SQL

Yes you can insert but not as similar to SQL.

In SQL we can insert the row level data, but here you can insert by fields (columns).

During this you have to make sure target table and the query should have same datatype and same number of columns.

eg:

CREATE TABLE test(stu_name STRING,stu_id INT,stu_marks INT)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY ','
STORED AS TEXTFILE;

INSERT OVERWRITE TABLE test SELECT lang_name, lang_id, lang_legacy_id FROM export_table;

Where is Python's sys.path initialized from?

Python really tries hard to intelligently set sys.path. How it is set can get really complicated. The following guide is a watered-down, somewhat-incomplete, somewhat-wrong, but hopefully-useful guide for the rank-and-file python programmer of what happens when python figures out what to use as the initial values of sys.path, sys.executable, sys.exec_prefix, and sys.prefix on a normal python installation.

First, python does its level best to figure out its actual physical location on the filesystem based on what the operating system tells it. If the OS just says "python" is running, it finds itself in $PATH. It resolves any symbolic links. Once it has done this, the path of the executable that it finds is used as the value for sys.executable, no ifs, ands, or buts.

Next, it determines the initial values for sys.exec_prefix and sys.prefix.

If there is a file called pyvenv.cfg in the same directory as sys.executable or one directory up, python looks at it. Different OSes do different things with this file.

One of the values in this config file that python looks for is the configuration option home = <DIRECTORY>. Python will use this directory instead of the directory containing sys.executable when it dynamically sets the initial value of sys.prefix later. If the applocal = true setting appears in the pyvenv.cfg file on Windows, but not the home = <DIRECTORY> setting, then sys.prefix will be set to the directory containing sys.executable.

Next, the PYTHONHOME environment variable is examined. On Linux and Mac, sys.prefix and sys.exec_prefix are set to the PYTHONHOME environment variable, if it exists, superseding any home = <DIRECTORY> setting in pyvenv.cfg. On Windows, sys.prefix and sys.exec_prefix is set to the PYTHONHOME environment variable, if it exists, unless a home = <DIRECTORY> setting is present in pyvenv.cfg, which is used instead.

Otherwise, these sys.prefix and sys.exec_prefix are found by walking backwards from the location of sys.executable, or the home directory given by pyvenv.cfg if any.

If the file lib/python<version>/dyn-load is found in that directory or any of its parent directories, that directory is set to be to be sys.exec_prefix on Linux or Mac. If the file lib/python<version>/os.py is is found in the directory or any of its subdirectories, that directory is set to be sys.prefix on Linux, Mac, and Windows, with sys.exec_prefix set to the same value as sys.prefix on Windows. This entire step is skipped on Windows if applocal = true is set. Either the directory of sys.executable is used or, if home is set in pyvenv.cfg, that is used instead for the initial value of sys.prefix.

If it can't find these "landmark" files or sys.prefix hasn't been found yet, then python sets sys.prefix to a "fallback" value. Linux and Mac, for example, use pre-compiled defaults as the values of sys.prefix and sys.exec_prefix. Windows waits until sys.path is fully figured out to set a fallback value for sys.prefix.

Then, (what you've all been waiting for,) python determines the initial values that are to be contained in sys.path.

The directory of the script which python is executing is added to sys.path. On Windows, this is always the empty string, which tells python to use the full path where the script is located instead.
The contents of PYTHONPATH environment variable, if set, is added to sys.path, unless you're on Windows and applocal is set to true in pyvenv.cfg.
The zip file path, which is <prefix>/lib/python35.zip on Linux/Mac and os.path.join(os.dirname(sys.executable), "python.zip") on Windows, is added to sys.path.
If on Windows and no applocal = true was set in pyvenv.cfg, then the contents of the subkeys of the registry key HK_CURRENT_USER\Software\Python\PythonCore\<DLLVersion>\PythonPath\ are added, if any.
If on Windows and no applocal = true was set in pyvenv.cfg, and sys.prefix could not be found, then the core contents of the of the registry key HK_CURRENT_USER\Software\Python\PythonCore\<DLLVersion>\PythonPath\ is added, if it exists;
If on Windows and no applocal = true was set in pyvenv.cfg, then the contents of the subkeys of the registry key HK_LOCAL_MACHINE\Software\Python\PythonCore\<DLLVersion>\PythonPath\ are added, if any.
If on Windows and no applocal = true was set in pyvenv.cfg, and sys.prefix could not be found, then the core contents of the of the registry key HK_CURRENT_USER\Software\Python\PythonCore\<DLLVersion>\PythonPath\ is added, if it exists;
If on Windows, and PYTHONPATH was not set, the prefix was not found, and no registry keys were present, then the relative compile-time value of PYTHONPATH is added; otherwise, this step is ignored.
Paths in the compile-time macro PYTHONPATH are added relative to the dynamically-found sys.prefix.
On Mac and Linux, the value of sys.exec_prefix is added. On Windows, the directory which was used (or would have been used) to search dynamically for sys.prefix is added.

At this stage on Windows, if no prefix was found, then python will try to determine it by searching all the directories in sys.path for the landmark files, as it tried to do with the directory of sys.executable previously, until it finds something. If it doesn't, sys.prefix is left blank.

Finally, after all this, Python loads the site module, which adds stuff yet further to sys.path:

It starts by constructing up to four directories from a head and a tail part. For the head part, it uses sys.prefix and sys.exec_prefix; empty heads are skipped. For the tail part, it uses the empty string and then lib/site-packages (on Windows) or lib/pythonX.Y/site-packages and then lib/site-python (on Unix and Macintosh). For each of the distinct head-tail combinations, it sees if it refers to an existing directory, and if so, adds it to sys.path and also inspects the newly added path for configuration files.

How to detect when keyboard is shown and hidden

Swift 3:

NotificationCenter.default.addObserver(self, selector: #selector(viewController.keyboardWillShow(_:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(viewController.keyboardWillHide(_:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)

func keyboardWillShow(_ notification: NSNotification){
    // Do something here
}

func keyboardWillHide(_ notification: NSNotification){
    // Do something here
}

Twitter Bootstrap Button Text Word Wrap

You can simply add this class.

.btn {
    white-space:normal !important;
    word-wrap: break-word; 
}

html cellpadding the left side of a cell

Well, as suggested by Hellfire you can use td width or you could place an element in the td and adjust its width. We could not use

CSS property Padding

as in Microsoft Outlook padding does not work. So what I had to do is,

<table>
    <tr>
        <td><span style="display: inline-block; width: 40px;"></span><span>Content<span></td>
        <td>Content</td>
    </tr>
</table>

With this you can adjust right and left spacing. For top and bottom spacing you could use td's height property. Like,

 <table>
        <tr>
            <td style="vertical-align: top; height: 100px;">Content</td>
            <td>Content</td>
        </tr>
    </table>

This will increase bottom space.

Hope it will work for you guys. :)

php, mysql - Too many connections to database error

Please check if you open up a new connection with each of your requests (mysql_connect(...)). If you do so, make sure you close the connection afterwards (using mysql_close($link)).

Also, you should consider changing this behaviour as keeping one steady connection for each user may be a better way to accomplish your task.

If you didn't already, take a look at this obvious, but nonetheless useful information resource: http://php.net/manual/function.mysql-connect.php

Setting environment variables via launchd.conf no longer works in OS X Yosemite/El Capitan/macOS Sierra/Mojave?

It is possible to set environment variables on Mac OS X 10.10 Yosemite with 3 files + 2 commands.

Main file with environment variables definition:

$ ls -la /etc/environment 
-r-xr-xr-x  1 root  wheel  369 Oct 21 04:42 /etc/environment
$ cat /etc/environment
#!/bin/sh

set -e

syslog -s -l warn "Set environment variables with /etc/environment $(whoami) - start"

launchctl setenv JAVA_HOME      /usr/local/jdk1.7
launchctl setenv MAVEN_HOME     /opt/local/share/java/maven3

if [ -x /usr/libexec/path_helper ]; then
    export PATH=""
    eval `/usr/libexec/path_helper -s`
    launchctl setenv PATH $PATH
fi

osascript -e 'tell app "Dock" to quit'

syslog -s -l warn "Set environment variables with /etc/environment $(whoami) - complete"

Service definition to load environment variables for user applications (terminal, IDE, ...):

$ ls -la /Library/LaunchAgents/environment.user.plist
-rw-------  1 root  wheel  504 Oct 21 04:37 /Library/LaunchAgents/environment.user.plist
$ sudo cat /Library/LaunchAgents/environment.user.plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>environment.user</string>
    <key>ProgramArguments</key>
    <array>
            <string>/etc/environment</string>
    </array>
    <key>KeepAlive</key>
    <false/>
    <key>RunAtLoad</key>
    <true/>
    <key>WatchPaths</key>
    <array>
        <string>/etc/environment</string>
    </array>
</dict>
</plist>

The same service definition for root user applications:

$ ls -la /Library/LaunchDaemons/environment.plist
-rw-------  1 root  wheel  499 Oct 21 04:38 /Library/LaunchDaemons/environment.plist
$ sudo cat /Library/LaunchDaemons/environment.plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>environment</string>
    <key>ProgramArguments</key>
    <array>
            <string>/etc/environment</string>
    </array>
    <key>KeepAlive</key>
    <false/>
    <key>RunAtLoad</key>
    <true/>
    <key>WatchPaths</key>
    <array>
        <string>/etc/environment</string>
    </array>
</dict>
</plist>

And finally we should register these services:

$ launchctl load -w /Library/LaunchAgents/environment.user.plist
$ sudo launchctl load -w /Library/LaunchDaemons/environment.plist

What we get:

The only place to declare system environment variables: /etc/environment
Instant auto-update of environment variables after modification of /etc/environment file - just relaunch your application

Issues / problems:

In order your env variables were correctly taken by applications after system reboot you will need:

either login twice: login => logout => login
or close & re-open applications manually, where env variables should be taken
or do NOT use feature "Reopen windows when logging back".

This happens due to Apple denies explicit ordering of loaded services, so env variables are registered in parallel with processing of the "reopen queue".

But actually, I reboot my system only several times per year (on big updates), so it is not a big deal.

How do I determine if a port is open on a Windows server?

Another option is tcping.

For example:

tcping host port

PostgreSQL: FOREIGN KEY/ON DELETE CASCADE

A foreign key with a cascade delete means that if a record in the parent table is deleted, then the corresponding records in the child table will automatically be deleted. This is called a cascade delete.

You are saying in a opposite way, this is not that when you delete from child table then records will be deleted from parent table.

UPDATE 1:

ON DELETE CASCADE option is to specify whether you want rows deleted in a child table when corresponding rows are deleted in the parent table. If you do not specify cascading deletes, the default behaviour of the database server prevents you from deleting data in a table if other tables reference it.

If you specify this option, later when you delete a row in the parent table, the database server also deletes any rows associated with that row (foreign keys) in a child table. The principal advantage to the cascading-deletes feature is that it allows you to reduce the quantity of SQL statements you need to perform delete actions.

So it's all about what will happen when you delete rows from Parent table not from child table.

So in your case when user removes entries from CATs table then rows will be deleted from books table. :)

Hope this helps you :)

How to delete all instances of a character in a string in python?

Strings are immutable in Python, which means once a string is created, you cannot alter the contents of the strings. If at all, you need to change it, a new instance of the string will be created with the alterations.

Having that in mind, we have so many ways to solve this

Using str.replace,

>>> "it is icy".replace("i", "")
't s cy'

Using str.translate,

>>> "it is icy".translate(None, "i")
't s cy'

Using Regular Expression,

>>> import re
>>> re.sub(r'i', "", "it is icy")
't s cy'

Using comprehension as a filter,

>>> "".join([char for char in "it is icy" if char != "i"])
't s cy'

Using filter function

>>> "".join(filter(lambda char: char != "i", "it is icy"))
't s cy'

Timing comparison

def findreplace(m_string, char):
    m_string = list(m_string)
    for k in m_string:
        if k == char:
            del(m_string[m_string.index(k)])
    return "".join(m_string)

def replace(m_string, char):
    return m_string.replace("i", "")

def translate(m_string, char):
    return m_string.translate(None, "i")

from timeit import timeit

print timeit("findreplace('it is icy','i')", "from __main__ import findreplace")
print timeit("replace('it is icy','i')", "from __main__ import replace")
print timeit("translate('it is icy','i')", "from __main__ import translate")

Result

1.64474582672
0.29278588295
0.311302900314

str.replace and str.translate methods are 8 and 5 times faster than the accepted answer.

Note: Comprehension method and filter methods are expected to be slower, for this case, since they have to create list and then they have to be traversed again to construct a string. And re is a bit overkill for a single character replacement. So, they all are excluded from the timing comparison.

What is Join() in jQuery?

I use join to separate the word in array with "and, or , / , &"

EXAMPLE

HTML

<p>London Mexico Canada</p>
<div></div>

 newText = $("p").text().split(" ").join(" or ");
 $('div').text(newText);

Results

London or Mexico or Canada

What are .dex files in Android?

About the .dex File :

One of the most remarkable features of the Dalvik Virtual Machine (the workhorse under the Android system) is that it does not use Java bytecode. Instead, a homegrown format called DEX was introduced and not even the bytecode instructions are the same as Java bytecode instructions.

Compiled Android application code file.

Android programs are compiled into .dex (Dalvik Executable) files, which are in turn zipped into a single .apk file on the device. .dex files can be created by automatically translating compiled applications written in the Java programming language.

Dex file format:

 1. File Header
 2. String Table
 3. Class List
 4. Field Table
 5. Method Table
 6. Class Definition Table
 7. Field List
 8. Method List
 9. Code Header
10. Local Variable List

Android has documentation on the Dalvik Executable Format (.dex files). You can find out more over at the official docs: Dex File Format

.dex files are similar to java class files, but they were run under the Dalkvik Virtual Machine (DVM) on older Android versions, and compiled at install time on the device to native code with ART on newer Android versions.

You can decompile .dex using the dexdump tool which is provided in android-sdk.

There are also some Reverse Engineering Techniques to make a jar file or java class file from a .dex file.

Rails: Using greater than/less than with a where statement

Arel is your friend:

User.where(User.arel_table[:id].gt(200))

How to use jquery $.post() method to submit form values

You have to select and send the form data as well:

$("#post-btn").click(function(){        
    $.post("process.php", $("#reg-form").serialize(), function(data) {
        alert(data);
    });
});

Take a look at the documentation for the jQuery serialize method, which encodes the data from the form fields into a data-string to be sent to the server.

Android Canvas: drawing too large bitmap

This can be an issue with Glide. Use this while you are trying to load to many images and some of them are very large:

Glide.load("your image path")
                       .transform(
                               new MultiTransformation<>(
                                       new CenterCrop(),
                                       new RoundedCorners(
                                               holder.imgCompanyLogo.getResources()
                                                       .getDimensionPixelSize(R.dimen._2sdp)
                                       )
                               )
                       )
                       .error(R.drawable.ic_nfs_default)
                       .into(holder.imgCompanyLogo);
           }

facebook: permanent Page Access Token?

In addition to mentioned methods it is worth mentioning that for server-to-server applications, you can also use this form of permanent access token: app_id|app_secret This type of access token is called App Token. It can generally be used to call Graph API and query for public nodes within your application back-end. It is mentioned here: https://developers.facebook.com/docs/facebook-login/access-tokens

Git's famous "ERROR: Permission to .git denied to user"

This problem is also caused by:

If you are on a mac/linux, and are using 'ControlMaster' in your ~/.ssh/config, there may be some ssh control master processes running.

To find them, run:

ps aux | grep '\[mux\]'

And kill the relevant ones.

How to implement an android:background that doesn't stretch?

I had the same problem: you should only use a 9-patch image (.9.png) instead of your original picture.

Serge

How do I upgrade to Python 3.6 with conda?

Anaconda has not updated python internally to 3.6.

a) Method 1

If you wanted to update you will type conda update python
To update anaconda type conda update anaconda
If you want to upgrade between major python version like 3.5 to 3.6, you'll have to do
```
conda install python=$pythonversion$
```

b) Method 2 - Create a new environment (Better Method)

conda create --name py36 python=3.6

c) To get the absolute latest python(3.6.5 at time of writing)

conda create --name py365 python=3.6.5 --channel conda-forge

You can see all this from here

Also, refer to this for force upgrading

EDIT: Anaconda now has a Python 3.6 version here

How are POST and GET variables handled in Python?

Python is only a language, to get GET and POST data, you need a web framework or toolkit written in Python. Django is one, as Charlie points out, the cgi and urllib standard modules are others. Also available are Turbogears, Pylons, CherryPy, web.py, mod_python, fastcgi, etc, etc.

In Django, your view functions receive a request argument which has request.GET and request.POST. Other frameworks will do it differently.

Automatically open default email client and pre-populate content

Try this: It will open the default mail directly.

<a href="mailto:[email protected]"><img src="ICON2.png"></a>

Is there a way to use PhantomJS in Python?

In case you are using Buildout, you can easily automate the installation processes that Pykler describes using the gp.recipe.node recipe.

[nodejs]
recipe = gp.recipe.node
version = 0.10.32
npms = phantomjs
scripts = phantomjs

That part installs node.js as binary (at least on my system) and then uses npm to install PhantomJS. Finally it creates an entry point bin/phantomjs, which you can call the PhantomJS webdriver with. (To install Selenium, you need to specify it in your egg requirements or in the Buildout configuration.)

driver = webdriver.PhantomJS('bin/phantomjs')

How do I show running processes in Oracle DB?

I suspect you would just want to grab a few columns from V$SESSION and the SQL statement from V$SQL. Assuming you want to exclude the background processes that Oracle itself is running

SELECT sess.process, sess.status, sess.username, sess.schemaname, sql.sql_text
  FROM v$session sess,
       v$sql     sql
 WHERE sql.sql_id(+) = sess.sql_id
   AND sess.type     = 'USER'

The outer join is to handle those sessions that aren't currently active, assuming you want those. You could also get the sql_fulltext column from V$SQL which will have the full SQL statement rather than the first 1000 characters, but that is a CLOB and so likely a bit more complicated to deal with.

Realistically, you probably want to look at everything that is available in V$SESSION because it's likely that you can get a lot more information than SP_WHO provides.

Perl regular expression (using a variable as a search string with Perl operator characters included)

Use \Q to autoescape any potentially problematic characters in your variable.

if($text_to_search =~ m/\Q$search_string/) print "wee";

Android: adbd cannot run as root in production builds

The problem is that, even though your phone is rooted, the 'adbd' server on the phone does not use root permissions. You can try to bypass these checks or install a different adbd on your phone or install a custom kernel/distribution that includes a patched adbd.

Or, a much easier solution is to use 'adbd insecure' from chainfire which will patch your adbd on the fly. It's not permanent, so you have to run it before starting up the adb server (or else set it to run every boot). You can get the app from the google play store for a couple bucks:

https://play.google.com/store/apps/details?id=eu.chainfire.adbd&hl=en

Or you can get it for free, the author has posted a free version on xda-developers:

http://forum.xda-developers.com/showthread.php?t=1687590

Install it to your device (copy it to the device and open the apk file with a file manager), run adb insecure on the device, and finally kill the adb server on your computer:

% adb kill-server

And then restart the server and it should already be root.

Unable to generate an explicit migration in entity framework

Just my two cents:

My scenario:

I restored my local database to a working state.
Already had migrations already applied to it.
Whenever I tried adding a new migration i got the error about pending migrations as mentioned my the OP.

Solution:

To get around this i just provided more explicit parameters:

Add-Migration -ConnectionString "Server=localhost\SQLEXPRESS;Database=YourDataBase;Trusted_Connection=True;" -ConnectionProviderName "System.Data.SqlClient" -verbose

I am lead to believe that you can set a setting in your app.config folder to allow you to default this behaviour so you don't have to provide explicit parameters everytime. However I am not sure on how to do this.

Open file by its full path in C++

You can use a full path with the fstream classes. The folowing code attempts to open the file demo.txt in the root of the C: drive. Note that as this is an input operation, the file must already exist.

#include <fstream>
#include <iostream>
using namespace std;

int main() {
   ifstream ifs( "c:/demo.txt" );       // note no mode needed
   if ( ! ifs.is_open() ) {                 
      cout <<" Failed to open" << endl;
   }
   else {
      cout <<"Opened OK" << endl;
   }
}

What does this code produce on your system?

How to make div appear in front of another?

Upper div use higher z-index and lower div use lower z-index then use absolute/fixed/relative position

Add attribute 'checked' on click jquery

If .attr() isn't working for you (especially when checking and unchecking boxes in succession), use .prop() instead of .attr().

CSS3 transition on click using pure CSS

As jeremyjjbrow said, :active pseudo won't persist. But there's a hack for doing it on pure css. You can wrap it on a <a> tag, and apply the :active on it, like this:

<a class="test">
    <img class="crossRotate" src="images/cross.png" alt="Cross Menu button" />
 </a>

And the css:

.test:active .crossRotate {
    transform: rotate(45deg);
    -webkit-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
    }

Try it out... It works (at least on Chrome)!

Save and load MemoryStream to/from a file

For loading a file, I like this a lot better

MemoryStream ms = new MemoryStream();
using (FileStream fs = File.OpenRead(file))
{
    fs.CopyTo(ms);
}

SoapUI "failed to load url" error when loading WSDL

I had this issue when trying to use a SOCKS proxy. It appears that SoapUI does not support SOCKS proxys. I am using the Boomerang Chrome app instead.

Pass Multiple Parameters to jQuery ajax call

Just to add on [This line perfectly work in Asp.net& find web-control Fields in jason Eg:<%Fieldname%>]

 data: "{LocationName:'" + document.getElementById('<%=txtLocationName.ClientID%>').value + "',AreaID:'" + document.getElementById('<%=DropDownArea.ClientID%>').value + "'}",

Task vs Thread differences

The Thread class is used for creating and manipulating a thread in Windows.

A Task represents some asynchronous operation and is part of the Task Parallel Library, a set of APIs for running tasks asynchronously and in parallel.

In the days of old (i.e. before TPL) it used to be that using the Thread class was one of the standard ways to run code in the background or in parallel (a better alternative was often to use a ThreadPool), however this was cumbersome and had several disadvantages, not least of which was the performance overhead of creating a whole new thread to perform a task in the background.

Nowadays using tasks and the TPL is a far better solution 90% of the time as it provides abstractions which allows far more efficient use of system resources. I imagine there are a few scenarios where you want explicit control over the thread on which you are running your code, however generally speaking if you want to run something asynchronously your first port of call should be the TPL.

Command line to remove an environment variable from the OS level configuration

The command in DougWare's answer did not work, but this did:

reg delete "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" /v FOOBAR /f

The shortcut HKLM can be used for HKEY_LOCAL_MACHINE.

How to get text in QlineEdit when QpushButton is pressed in a string?

My first suggestion is to use Designer to create your GUIs. Typing them out yourself sucks, takes more time, and you will definitely make more mistakes than Designer.

Here are some PyQt tutorials to help get you on the right track. The first one in the list is where you should start.

A good guide for figuring out what methods are available for specific classes is the PyQt4 Class Reference. In this case you would look up QLineEdit and see the there is a text method.

To answer your specific question:

To make your GUI elements available to the rest of the object, preface them with self.

import sys
from PyQt4.QtCore import SIGNAL
from PyQt4.QtGui import QDialog, QApplication, QPushButton, QLineEdit, QFormLayout

class Form(QDialog):
    def __init__(self, parent=None):
        super(Form, self).__init__(parent)

        self.le = QLineEdit()
        self.le.setObjectName("host")
        self.le.setText("Host")

        self.pb = QPushButton()
        self.pb.setObjectName("connect")
        self.pb.setText("Connect") 

        layout = QFormLayout()
        layout.addWidget(self.le)
        layout.addWidget(self.pb)

        self.setLayout(layout)
        self.connect(self.pb, SIGNAL("clicked()"),self.button_click)
        self.setWindowTitle("Learning")

    def button_click(self):
        # shost is a QString object
        shost = self.le.text()
        print shost


app = QApplication(sys.argv)
form = Form()
form.show()
app.exec_()

How can I correctly format currency using jquery?

Expanding upon Melu's answer you can do this to functionalize the code and handle negative amounts.

Sample Output:
$5.23
-$5.23

function formatCurrency(total) {
    var neg = false;
    if(total < 0) {
        neg = true;
        total = Math.abs(total);
    }
    return (neg ? "-$" : '$') + parseFloat(total, 10).toFixed(2).replace(/(\d)(?=(\d{3})+\.)/g, "$1,").toString();
}

How do you create a temporary table in an Oracle database?

CREATE GLOBAL TEMPORARY TABLE Table_name
    (startdate DATE,
     enddate DATE,
     class CHAR(20))
  ON COMMIT DELETE ROWS;

Refreshing all the pivot tables in my excel workbook with a macro

Yes.

ThisWorkbook.RefreshAll

Or, if your Excel version is old enough,

Dim Sheet as WorkSheet, Pivot as PivotTable
For Each Sheet in ThisWorkbook.WorkSheets
    For Each Pivot in Sheet.PivotTables
        Pivot.RefreshTable
        Pivot.Update
    Next
Next

Display/Print one column from a DataFrame of Series in Pandas

For printing the Name column

df['Name']

How can I change column types in Spark SQL's DataFrame?

    val fact_df = df.select($"data"(30) as "TopicTypeId", $"data"(31) as "TopicId",$"data"(21).cast(FloatType).as( "Data_Value_Std_Err")).rdd
    //Schema to be applied to the table
    val fact_schema = (new StructType).add("TopicTypeId", StringType).add("TopicId", StringType).add("Data_Value_Std_Err", FloatType)

    val fact_table = sqlContext.createDataFrame(fact_df, fact_schema).dropDuplicates()

href overrides ng-click in Angular.js

In Angular, <a>s are directives. As such, if you have an empty href or no href, Angular will call event.preventDefault.

From the source:

    element.on('click', function(event){
      // if we have no href url, then don't navigate anywhere.
      if (!element.attr(href)) {
        event.preventDefault();
      }
    });

Here's a plnkr demonstrating the missing href scenario.

ConnectionTimeout versus SocketTimeout

A connection timeout occurs only upon starting the TCP connection. This usually happens if the remote machine does not answer. This means that the server has been shut down, you used the wrong IP/DNS name, wrong port or the network connection to the server is down.

A socket timeout is dedicated to monitor the continuous incoming data flow. If the data flow is interrupted for the specified timeout the connection is regarded as stalled/broken. Of course this only works with connections where data is received all the time.

By setting socket timeout to 1 this would require that every millisecond new data is received (assuming that you read the data block wise and the block is large enough)!

If only the incoming stream stalls for more than a millisecond you are running into a timeout.

How to get a right click mouse event? Changing EventArgs to MouseEventArgs causes an error in Form1Designer?

See the code below, this is the complete code about getting a mouse event(rightclick, leftclick) And you can DIY this code and make it on your own.

using System; 
using System.Drawing; 
using System.Windows.Forms; 
using System.Runtime.InteropServices; 

namespace Demo_mousehook_csdn
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        MouseHook mh;

        private void Form1_Load(object sender, EventArgs e)
        {
            mh = new MouseHook();
            mh.SetHook();
            mh.MouseMoveEvent += mh_MouseMoveEvent;
            mh.MouseClickEvent += mh_MouseClickEvent;
            mh.MouseDownEvent += mh_MouseDownEvent;
            mh.MouseUpEvent += mh_MouseUpEvent;
        }
        private void mh_MouseDownEvent(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                richTextBox1.AppendText("Left Button Press\n");
            }
            if (e.Button == MouseButtons.Right)
            {
                richTextBox1.AppendText("Right Button Press\n");
            }
        }

        private void mh_MouseUpEvent(object sender, MouseEventArgs e)
        {

            if (e.Button == MouseButtons.Left)
            {
                richTextBox1.AppendText("Left Button Release\n");
            }
            if (e.Button == MouseButtons.Right)
            {
                richTextBox1.AppendText("Right Button Release\n");
            }

        }
        private void mh_MouseClickEvent(object sender, MouseEventArgs e)
        {
            //MessageBox.Show(e.X + "-" + e.Y);
            if (e.Button == MouseButtons.Left)
            {
                string sText = "(" + e.X.ToString() + "," + e.Y.ToString() + ")";
                label1.Text = sText;
            }
        }

        private void mh_MouseMoveEvent(object sender, MouseEventArgs e)
        {
            int x = e.Location.X;
            int y = e.Location.Y;
            textBox1.Text = x + "";
            textBox2.Text = y + "";
        }
        private void Form1_FormClosed(object sender, FormClosedEventArgs e)
        {
            mh.UnHook();
        }

        private void Form1_FormClosed_1(object sender, FormClosedEventArgs e)
        {
            mh.UnHook();
        }

        private void richTextBox1_TextChanged(object sender, EventArgs e)
        {

        }
    }

    public class Win32Api
    {
        [StructLayout(LayoutKind.Sequential)]
        public class POINT
        {
            public int x;
            public int y;
        }
        [StructLayout(LayoutKind.Sequential)]
        public class MouseHookStruct
        {
            public POINT pt;
            public int hwnd;
            public int wHitTestCode;
            public int dwExtraInfo;
        }
        public delegate int HookProc(int nCode, IntPtr wParam, IntPtr lParam);
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern bool UnhookWindowsHookEx(int idHook);
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern int CallNextHookEx(int idHook, int nCode, IntPtr wParam, IntPtr lParam);
    }

    public class MouseHook
    {
        private Point point;
        private Point Point
        {
            get { return point; }
            set
            {
                if (point != value)
                {
                    point = value;
                    if (MouseMoveEvent != null)
                    {
                        var e = new MouseEventArgs(MouseButtons.None, 0, point.X, point.Y, 0);
                        MouseMoveEvent(this, e);
                    }
                }
            }
        }
        private int hHook;
        private const int WM_MOUSEMOVE = 0x200;
        private const int WM_LBUTTONDOWN = 0x201;
        private const int WM_RBUTTONDOWN = 0x204;
        private const int WM_MBUTTONDOWN = 0x207;
        private const int WM_LBUTTONUP = 0x202;
        private const int WM_RBUTTONUP = 0x205;
        private const int WM_MBUTTONUP = 0x208;
        private const int WM_LBUTTONDBLCLK = 0x203;
        private const int WM_RBUTTONDBLCLK = 0x206;
        private const int WM_MBUTTONDBLCLK = 0x209;
        public const int WH_MOUSE_LL = 14;
        public Win32Api.HookProc hProc;
        public MouseHook()
        {
            this.Point = new Point();
        }
        public int SetHook()
        {
            hProc = new Win32Api.HookProc(MouseHookProc);
            hHook = Win32Api.SetWindowsHookEx(WH_MOUSE_LL, hProc, IntPtr.Zero, 0);
            return hHook;
        }
        public void UnHook()
        {
            Win32Api.UnhookWindowsHookEx(hHook);
        }
        private int MouseHookProc(int nCode, IntPtr wParam, IntPtr lParam)
        {
            Win32Api.MouseHookStruct MyMouseHookStruct = (Win32Api.MouseHookStruct)Marshal.PtrToStructure(lParam, typeof(Win32Api.MouseHookStruct));
            if (nCode < 0)
            {
                return Win32Api.CallNextHookEx(hHook, nCode, wParam, lParam);
            }
            else
            {
                if (MouseClickEvent != null)
                {
                    MouseButtons button = MouseButtons.None;
                    int clickCount = 0;
                    switch ((Int32)wParam)
                    {
                        case WM_LBUTTONDOWN:
                            button = MouseButtons.Left;
                            clickCount = 1;
                            MouseDownEvent(this, new MouseEventArgs(button, clickCount, point.X, point.Y, 0));
                            break;
                        case WM_RBUTTONDOWN:
                            button = MouseButtons.Right;
                            clickCount = 1;
                            MouseDownEvent(this, new MouseEventArgs(button, clickCount, point.X, point.Y, 0));
                            break;
                        case WM_MBUTTONDOWN:
                            button = MouseButtons.Middle;
                            clickCount = 1;
                            MouseDownEvent(this, new MouseEventArgs(button, clickCount, point.X, point.Y, 0));
                            break;
                        case WM_LBUTTONUP:
                            button = MouseButtons.Left;
                            clickCount = 1;
                            MouseUpEvent(this, new MouseEventArgs(button, clickCount, point.X, point.Y, 0));
                            break;
                        case WM_RBUTTONUP:
                            button = MouseButtons.Right;
                            clickCount = 1;
                            MouseUpEvent(this, new MouseEventArgs(button, clickCount, point.X, point.Y, 0));
                            break;
                        case WM_MBUTTONUP:
                            button = MouseButtons.Middle;
                            clickCount = 1;
                            MouseUpEvent(this, new MouseEventArgs(button, clickCount, point.X, point.Y, 0));
                            break;
                    }

                    var e = new MouseEventArgs(button, clickCount, point.X, point.Y, 0);
                    MouseClickEvent(this, e);
                }
                this.Point = new Point(MyMouseHookStruct.pt.x, MyMouseHookStruct.pt.y);
                return Win32Api.CallNextHookEx(hHook, nCode, wParam, lParam);
            }
        }

        public delegate void MouseMoveHandler(object sender, MouseEventArgs e);
        public event MouseMoveHandler MouseMoveEvent;

        public delegate void MouseClickHandler(object sender, MouseEventArgs e);
        public event MouseClickHandler MouseClickEvent;

        public delegate void MouseDownHandler(object sender, MouseEventArgs e);
        public event MouseDownHandler MouseDownEvent;

        public delegate void MouseUpHandler(object sender, MouseEventArgs e);
        public event MouseUpHandler MouseUpEvent;

    }
}

You can download the demo And the tutorial here : C# Mouse Hook Demo

How do I sum values in a column that match a given condition using pandas?

The essential idea here is to select the data you want to sum, and then sum them. This selection of data can be done in several different ways, a few of which are shown below.

Boolean indexing

Arguably the most common way to select the values is to use Boolean indexing.

With this method, you find out where column 'a' is equal to 1 and then sum the corresponding rows of column 'b'. You can use loc to handle the indexing of rows and columns:

>>> df.loc[df['a'] == 1, 'b'].sum()
15

The Boolean indexing can be extended to other columns. For example if df also contained a column 'c' and we wanted to sum the rows in 'b' where 'a' was 1 and 'c' was 2, we'd write:

df.loc[(df['a'] == 1) & (df['c'] == 2), 'b'].sum()

Query

Another way to select the data is to use query to filter the rows you're interested in, select column 'b' and then sum:

>>> df.query("a == 1")['b'].sum()
15

Again, the method can be extended to make more complicated selections of the data:

df.query("a == 1 and c == 2")['b'].sum()

Note this is a little more concise than the Boolean indexing approach.

Groupby

The alternative approach is to use groupby to split the DataFrame into parts according to the value in column 'a'. You can then sum each part and pull out the value that the 1s added up to:

>>> df.groupby('a')['b'].sum()[1]
15

This approach is likely to be slower than using Boolean indexing, but it is useful if you want check the sums for other values in column a:

>>> df.groupby('a')['b'].sum()
a
1    15
2     8

How do I determine the size of an object in Python?

I use this trick... May won't be accurate on small objects, but I think it's much more accurate for a complex object (like pygame surface) rather than sys.getsizeof()

import pygame as pg
import os
import psutil
import time


process = psutil.Process(os.getpid())
pg.init()    
vocab = ['hello', 'me', 'you', 'she', 'he', 'they', 'we',
         'should', 'why?', 'necessarily', 'do', 'that']

font = pg.font.SysFont("monospace", 100, True)

dct = {}

newMem = process.memory_info().rss  # don't mind this line
Str = f'store ' + f'Nothing \tsurface use about '.expandtabs(15) + \
      f'0\t bytes'.expandtabs(9)  # don't mind this assignment too

usedMem = process.memory_info().rss

for word in vocab:
    dct[word] = font.render(word, True, pg.Color("#000000"))

    time.sleep(0.1)  # wait a moment

    # get total used memory of this script:
    newMem = process.memory_info().rss
    Str = f'store ' + f'{word}\tsurface use about '.expandtabs(15) + \
          f'{newMem - usedMem}\t bytes'.expandtabs(9)

    print(Str)
    usedMem = newMem

On my windows 10, python 3.7.3, the output is:

store hello          surface use about 225280    bytes
store me             surface use about 61440     bytes
store you            surface use about 94208     bytes
store she            surface use about 81920     bytes
store he             surface use about 53248     bytes
store they           surface use about 114688    bytes
store we             surface use about 57344     bytes
store should         surface use about 172032    bytes
store why?           surface use about 110592    bytes
store necessarily    surface use about 311296    bytes
store do             surface use about 57344     bytes
store that           surface use about 110592    bytes

How to hide first section header in UITableView (grouped style)

Try this if you want to remove all section header completely

func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
    return CGFloat.leastNormalMagnitude
}

func tableView(_ tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat {
    return CGFloat.leastNormalMagnitude
}

ng-repeat :filter by single field

Best way to do this is to use a function:

html

<div ng-repeat="product in products | filter: myFilter">

javascript

$scope.myFilter = function (item) { 
    return item === 'red' || item === 'blue'; 
};

Alternatively, you can use ngHide or ngShow to dynamically show and hide elements based on a certain criteria.

How do I parse a string into a number with Dart?

Convert String to Int

var myInt = int.parse('12345');
assert(myInt is int);
print(myInt); // 12345
print(myInt.runtimeType);

Convert String to Double

var myDouble = double.parse('123.45');
assert(myInt is double);
print(myDouble); // 123.45
print(myDouble.runtimeType);

Example in DartPad

What is "Connect Timeout" in sql server connection string?

Gets the time to wait while trying to establish a connection before terminating the attempt and generating an error.

http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnection.connectiontimeout%28v=vs.110%29.aspx

Encapsulation vs Abstraction?

Abstraction is the concept of describing something in simpler terms, i.e abstracting away the details, in order to focus on what is important (This is also seen in abstract art, for example, where the artist focuses on the building blocks of images, such as colour or shapes). The same idea translates to OOP by using an inheritance hierarchy, where more abstract concepts are at the top and more concrete ideas, at the bottom, build upon their abstractions. At its most abstract level there is no implementation details at all and perhaps very few commonalities, which are added as the abstraction decreases.

As an example, at the top might be an interface with a single method, then the next level, provides several abstract classes, which may or may not fill in some of the details about the top level, but branches by adding their own abstract methods, then for each of these abstract classes are concrete classes providing implementations of all the remaining methods.

Encapsulation is a technique. It may or may not be for aiding in abstraction, but it is certainly about information hiding and/or organisation. It demands data and functions be grouped in some way - of course good OOP practice demands that they should be grouped by abstraction. However, there are other uses which just aid in maintainability etc.

How do I force "git pull" to overwrite local files?

Despite the original question, the top answers can cause problems for people who have a similar problem, but don't want to lose their local files. For example, see Al-Punk and crizCraig's comments.

The following version commits your local changes to a temporary branch (tmp), checks out the original branch (which I'm assuming is master) and merges the updates. You could do this with stash, but I've found it's usually easier to simply use the branch / merge approach.

git checkout -b tmp
git add *; git commit -am "my temporary files"
git checkout master

git fetch origin master
git merge -s recursive -X theirs origin master

where we assume the other repository is origin master.

Check whether a value is a number in JavaScript or jQuery

function isNumber(n) {
  return !isNaN(parseFloat(n)) && isFinite(n);
}

How to get nth jQuery element

You can use the :eq selector, for example:

$("td:eq(2)").css("color", "red"); // gets the third td element

Or the eq(int) function:

$("td").eq(2).css("color", "red");

Also, remember that the indexes are zero-based.

DB query builder toArray() laravel 4

try this one

DB::table('user')->where('name','Jhon')->get();

just remove the "=" sign . . . .because you are trying to array just the name 'jhon' . . . . . . . .I hope it's help you . .

"static const" vs "#define" vs "enum"

A simple difference:

At pre-processing time, the constant is replaced with its value. So you could not apply the dereference operator to a define, but you can apply the dereference operator to a variable.

As you would suppose, define is faster that static const.

For example, having:

#define mymax 100

you can not do printf("address of constant is %p",&mymax);.

But having

const int mymax_var=100

you can do printf("address of constant is %p",&mymax_var);.

To be more clear, the define is replaced by its value at the pre-processing stage, so we do not have any variable stored in the program. We have just the code from the text segment of the program where the define was used.

However, for static const we have a variable that is allocated somewhere. For gcc, static const are allocated in the text segment of the program.

Above, I wanted to tell about the reference operator so replace dereference with reference.

UTF-8 encoding in JSP page

You have to make sure the file is been saved with UTF-8 encoding. You can do it with several plain text editors. With Notepad++, i.e., you can choose in the menu Encoding-->Encode in UTF-8. You can also do it even with Windows' Notepad (Save As --> Encoding UTF-8). If you are using Eclipse, you can set it in the file's Properties.

Also, check if the problem is that you have to escape those characters. It wouldn't be strange that were your problem, as one of the characters is &.

Multi-gradient shapes

Try this method then you can do every thing you want.
It is like a stack so be careful which item comes first or last.

<?xml version="1.0" encoding="utf-8"?>
<layer-list
xmlns:android="http://schemas.android.com/apk/res/android">
<item android:right="50dp" android:start="10dp" android:left="10dp">
    <shape
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:shape="rectangle">
        <corners android:radius="3dp" />
        <solid android:color="#012d08"/>
    </shape>
</item>
<item android:top="50dp">
    <shape android:shape="rectangle">
        <solid android:color="#7c4b4b" />
    </shape>
</item>
<item android:top="90dp" android:end="60dp">
    <shape android:shape="rectangle">
        <solid android:color="#e2cc2626" />
    </shape>
</item>
<item android:start="50dp" android:bottom="20dp" android:top="120dp">
    <shape android:shape="rectangle">
        <solid android:color="#360e0e" />
    </shape>
</item>

How to connect to a remote Windows machine to execute commands using python?

pypsrp - Python PowerShell Remoting Protocol Client library

At a basic level, you can use this library to;

Execute a cmd command
Run another executable
Execute PowerShell scripts
Copy a file from the localhost to the remote Windows host
Fetch a file from the remote Windows host to the localhost
Create a Runspace Pool that contains one or multiple PowerShell pipelines and execute them asynchronously
Support for a reference host base implementation of PSRP for interactive scripts

REF: https://github.com/jborean93/pypsrp

Regular expression to match non-ASCII characters?

The situation with regexes, Unicode, and Javascript sucks. It's ridiculous that programmers should have to rely on external libraries to recognize that "??fa" is a word, or even that "é" is a letter.

But so it goes.

This guy has written a good library for handling Unicode in Javascript Regexes:

http://blog.stevenlevithan.com/archives/javascript-regex-and-unicode

The Unicode stuff is a plugin to this regex library:

http://xregexp.com/

Here's a post about the Unicode extension:

http://blog.stevenlevithan.com/archives/xregexp-unicode-plugin

And the extension page itself:

http://xregexp.com/plugins/

Great work but it still bums me out that Javascript is so backwards in this regard.

(He wrote a book for O'Reilly about the topic so it's quite possible that he knows what he's talking about.)

The way he implemented it is by adding tables of characters with certain properties. Then, when you contruct a regex with his library, \p{charclass} gets replaced with [allthecharactersintheclass].

How to take column-slices of dataframe in pandas

2017 Answer - pandas 0.20: .ix is deprecated. Use .loc

See the deprecation in the docs

.loc uses label based indexing to select both rows and columns. The labels being the values of the index or the columns. Slicing with .loc includes the last element.

Let's assume we have a DataFrame with the following columns:
foo, bar, quz, ant, cat, sat, dat.

# selects all rows and all columns beginning at 'foo' up to and including 'sat'
df.loc[:, 'foo':'sat']
# foo bar quz ant cat sat

.loc accepts the same slice notation that Python lists do for both row and columns. Slice notation being start:stop:step

# slice from 'foo' to 'cat' by every 2nd column
df.loc[:, 'foo':'cat':2]
# foo quz cat

# slice from the beginning to 'bar'
df.loc[:, :'bar']
# foo bar

# slice from 'quz' to the end by 3
df.loc[:, 'quz'::3]
# quz sat

# attempt from 'sat' to 'bar'
df.loc[:, 'sat':'bar']
# no columns returned

# slice from 'sat' to 'bar'
df.loc[:, 'sat':'bar':-1]
sat cat ant quz bar

# slice notation is syntatic sugar for the slice function
# slice from 'quz' to the end by 2 with slice function
df.loc[:, slice('quz',None, 2)]
# quz cat dat

# select specific columns with a list
# select columns foo, bar and dat
df.loc[:, ['foo','bar','dat']]
# foo bar dat

You can slice by rows and columns. For instance, if you have 5 rows with labels v, w, x, y, z

# slice from 'w' to 'y' and 'foo' to 'ant' by 3
df.loc['w':'y', 'foo':'ant':3]
#    foo ant
# w
# x
# y

Making macOS Installer Packages which are Developer ID ready

Our example project has two build targets: HelloWorld.app and Helper.app. We make a component package for each and combine them into a product archive.

A component package contains payload to be installed by the OS X Installer. Although a component package can be installed on its own, it is typically incorporated into a product archive.

Our tools: pkgbuild, productbuild, and pkgutil

After a successful "Build and Archive" open $BUILT_PRODUCTS_DIR in the Terminal.

$ cd ~/Library/Developer/Xcode/DerivedData/.../InstallationBuildProductsLocation
$ pkgbuild --analyze --root ./HelloWorld.app HelloWorldAppComponents.plist
$ pkgbuild --analyze --root ./Helper.app HelperAppComponents.plist

This give us the component-plist, you find the value description in the "Component Property List" section. pkgbuild -root generates the component packages, if you don't need to change any of the default properties you can omit the --component-plist parameter in the following command.

productbuild --synthesize results in a Distribution Definition.

$ pkgbuild --root ./HelloWorld.app \
    --component-plist HelloWorldAppComponents.plist \
    HelloWorld.pkg
$ pkgbuild --root ./Helper.app \
    --component-plist HelperAppComponents.plist \
    Helper.pkg
$ productbuild --synthesize \
    --package HelloWorld.pkg --package Helper.pkg \
    Distribution.xml

In the Distribution.xml you can change things like title, background, welcome, readme, license, and so on. You turn your component packages and distribution definition with this command into a product archive:

$ productbuild --distribution ./Distribution.xml \
    --package-path . \
    ./Installer.pkg

I recommend to take a look at iTunes Installers Distribution.xml to see what is possible. You can extract "Install iTunes.pkg" with:

$ pkgutil --expand "Install iTunes.pkg" "Install iTunes"

Lets put it together

I usually have a folder named Package in my project which includes things like Distribution.xml, component-plists, resources and scripts.

Add a Run Script Build Phase named "Generate Package", which is set to Run script only when installing:

VERSION=$(defaults read "${BUILT_PRODUCTS_DIR}/${FULL_PRODUCT_NAME}/Contents/Info" CFBundleVersion)

PACKAGE_NAME=`echo "$PRODUCT_NAME" | sed "s/ /_/g"`
TMP1_ARCHIVE="${BUILT_PRODUCTS_DIR}/$PACKAGE_NAME-tmp1.pkg"
TMP2_ARCHIVE="${BUILT_PRODUCTS_DIR}/$PACKAGE_NAME-tmp2"
TMP3_ARCHIVE="${BUILT_PRODUCTS_DIR}/$PACKAGE_NAME-tmp3.pkg"
ARCHIVE_FILENAME="${BUILT_PRODUCTS_DIR}/${PACKAGE_NAME}.pkg"

pkgbuild --root "${INSTALL_ROOT}" \
    --component-plist "./Package/HelloWorldAppComponents.plist" \
    --scripts "./Package/Scripts" \
    --identifier "com.test.pkg.HelloWorld" \
    --version "$VERSION" \
    --install-location "/" \
    "${BUILT_PRODUCTS_DIR}/HelloWorld.pkg"
pkgbuild --root "${BUILT_PRODUCTS_DIR}/Helper.app" \
    --component-plist "./Package/HelperAppComponents.plist" \
    --identifier "com.test.pkg.Helper" \
    --version "$VERSION" \
    --install-location "/" \
    "${BUILT_PRODUCTS_DIR}/Helper.pkg"
productbuild --distribution "./Package/Distribution.xml"  \
    --package-path "${BUILT_PRODUCTS_DIR}" \
    --resources "./Package/Resources" \
    "${TMP1_ARCHIVE}"

pkgutil --expand "${TMP1_ARCHIVE}" "${TMP2_ARCHIVE}"
    
# Patches and Workarounds

pkgutil --flatten "${TMP2_ARCHIVE}" "${TMP3_ARCHIVE}"

productsign --sign "Developer ID Installer: John Doe" \
    "${TMP3_ARCHIVE}" "${ARCHIVE_FILENAME}"

If you don't have to change the package after it's generated with productbuild you could get rid of the pkgutil --expand and pkgutil --flatten steps. Also you could use the --sign paramenter on productbuild instead of running productsign.

Sign an OS X Installer

Packages are signed with the Developer ID Installer certificate which you can download from Developer Certificate Utility.

They signing is done with the --sign "Developer ID Installer: John Doe" parameter of pkgbuild, productbuild or productsign.

Note that if you are going to create a signed product archive using productbuild, there is no reason to sign the component packages.

Developer Certificate Utility

All the way: Copy Package into Xcode Archive

To copy something into the Xcode Archive we can't use the Run Script Build Phase. For this we need to use a Scheme Action.

Edit Scheme and expand Archive. Then click post-actions and add a New Run Script Action:

In Xcode 6:

#!/bin/bash

PACKAGES="${ARCHIVE_PATH}/Packages"
  
PACKAGE_NAME=`echo "$PRODUCT_NAME" | sed "s/ /_/g"`
ARCHIVE_FILENAME="$PACKAGE_NAME.pkg"
PKG="${OBJROOT}/../BuildProductsPath/${CONFIGURATION}/${ARCHIVE_FILENAME}"

if [ -f "${PKG}" ]; then
    mkdir "${PACKAGES}"
    cp -r "${PKG}" "${PACKAGES}"
fi

In Xcode 5, use this value for PKG instead:

PKG="${OBJROOT}/ArchiveIntermediates/${TARGET_NAME}/BuildProductsPath/${CONFIGURATION}/${ARCHIVE_FILENAME}"

In case your version control doesn't store Xcode Scheme information I suggest to add this as shell script to your project so you can simple restore the action by dragging the script from the workspace into the post-action.

Scripting

There are two different kinds of scripting: JavaScript in Distribution Definition Files and Shell Scripts.

The best documentation about Shell Scripts I found in WhiteBox - PackageMaker How-to, but read this with caution because it refers to the old package format.

Apple Silicon

In order for the package to run as arm64, the Distribution file has to specify in its hostArchitectures section that it supports arm64 in addition to x86_64:

<options hostArchitectures="arm64,x86_64" />

Additional Reading

Known Issues and Workarounds

Destination Select Pane

The user is presented with the destination select option with only a single choice - "Install for all users of this computer". The option appears visually selected, but the user needs to click on it in order to proceed with the installation, causing some confusion.

Example showing the installer bug

Apples Documentation recommends to use <domains enable_anywhere ... /> but this triggers the new more buggy Destination Select Pane which Apple doesn't use in any of their Packages.

Using the deprecate <options rootVolumeOnly="true" /> give you the old Destination Select Pane. Example showing old Destination Select Pane

You want to install items into the current user’s home folder.

Short answer: DO NOT TRY IT!

Long answer: REALLY; DO NOT TRY IT! Read Installer Problems and Solutions. You know what I did even after reading this? I was stupid enough to try it. Telling myself I'm sure that they fixed the issues in 10.7 or 10.8.

First of all I saw from time to time the above mentioned Destination Select Pane Bug. That should have stopped me, but I ignored it. If you don't want to spend the week after you released your software answering support e-mails that they have to click once the nice blue selection DO NOT use this.

You are now thinking that your users are smart enough to figure the panel out, aren't you? Well here is another thing about home folder installation, THEY DON'T WORK!

I tested it for two weeks on around 10 different machines with different OS versions and what not, and it never failed. So I shipped it. Within an hour of the release I heart back from users who just couldn't install it. The logs hinted to permission issues you are not gonna be able to fix.

So let's repeat it one more time: We do not use the Installer for home folder installations!

RTFD for Welcome, Read-me, License and Conclusion is not accepted by productbuild.

Installer supported since the beginning RTFD files to make pretty Welcome screens with images, but productbuild doesn't accept them.

Workarounds: Use a dummy rtf file and replace it in the package by after productbuild is done.

Note: You can also have Retina images inside the RTFD file. Use multi-image tiff files for this: tiffutil -cat Welcome.tif Welcome_2x.tif -out FinalWelcome.tif. More details.

Starting an application when the installation is done with a BundlePostInstallScriptPath script:

#!/bin/bash

LOGGED_IN_USER_ID=`id -u "${USER}"`

if [ "${COMMAND_LINE_INSTALL}" = "" ]
then
    /bin/launchctl asuser "${LOGGED_IN_USER_ID}" /usr/bin/open -g PATH_OR_BUNDLE_ID
fi

exit 0

It is important to run the app as logged in user, not as the installer user. This is done with launchctl asuser uid path. Also we only run it when it is not a command line installation, done with installer tool or Apple Remote Desktop.

Merge / convert multiple PDF files into one PDF

This is the easiest solution if you have multiple files and do not want to type in the names one by one:

qpdf --empty --pages *.pdf -- out.pdf

Circular gradient in android

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:padding="10dp"
    android:shape="rectangle">

    <gradient
        android:endColor="@color/color1"
        android:gradientRadius="250dp"
        android:startColor="#8F15DA"
        android:type="radial" />

    <corners
        android:bottomLeftRadius="50dp"
        android:bottomRightRadius="50dp"
        android:radius="3dp"
        android:topLeftRadius="0dp"
        android:topRightRadius="50dp" />
</shape>

Rename multiple files in cmd

This works for your specific case:

ren file?.txt "file? 1.1.txt"

C non-blocking keyboard input

If you are happy just catching Control-C, it's a done deal. If you really want non-blocking I/O but you don't want the curses library, another alternative is to move lock, stock, and barrel to the AT&T sfio library. It's nice library patterned on C stdio but more flexible, thread-safe, and performs better. (sfio stands for safe, fast I/O.)

Implement an input with a mask

I taken from this thread decision Implement an input with a mask and adapted it for IE10, and added setter- and getter- functions.

BUT I TESTED FOR PHONE-mask ONLY

$(document).ready(function(){
    var el_arr = document.querySelectorAll("[placeholder][data-slots]");
    for (var el_ind=0; el_ind < el_arr.length; el_ind++ ){
        var el = el_arr[el_ind];
        var pattern = el.getAttribute("placeholder"),
            slots = new Set(el.getAttribute("data-slots") || "_"),
            prev = function(j){return Array.from(pattern, function(c,i){ return slots.has(c)? j=i+1: j;});}(0),
            first = pattern.split('').findIndex(function(c){return slots.has(c);} ),
            accept = new RegExp(el.getAttribute("data-accept") || "\\d", "g"),
            clean = function(input){input = input.match(accept) || [];return Array.from(pattern, function(c){return input[0] === c || slots.has(c) ? input.shift() || c : c;});},
            format = function(){
                var elem = this;
                var i_j_arr = [el.selectionStart, el.selectionEnd].map(function(i){
                    i = clean(el.value.slice(0, i)).findIndex(function(c){ return slots.has(c);});
                    return i<0? prev[prev.length-1]: elem.back? prev[i-1] || first: i;
                });
                el.value = clean(el.value).join('');
                el.setSelectionRange(i_j_arr[0], i_j_arr[1]);
                this.back = false;
            },
            // sdo added
            get_masked_value = function(){
                var input = this.value;
                var ret=[];
                for(var k in pattern){
                    if ( !input[k] )break;
                    if( slots.has(pattern[k]) && input[k]!=pattern[k]){
                        ret.push(input[k]);
                    } 
                } 
                return ret.join('');
            },
            set_masked_value = function(input){
                var ret=[];
                var index_in_value = 0;
                for(var k in pattern){
                    if( slots.has(pattern[k]) && input[index_in_value]){
                        ret.push(input[index_in_value]);
                        index_in_value++;
                    }
                    else{
                        ret.push(pattern[k]);
                    }
                } 
                this.value = ret.join('');
            }                    
        ;
        el.get_masked_value = get_masked_value;
        el.set_masked_value = set_masked_value;
        el.back = false;
        el.addEventListener("keydown", function(event){ this.back = event.key === "Backspace";});
        el.addEventListener("input", format);
        el.addEventListener("focus", format);
        el.addEventListener("blur", function() { return el.value === pattern && (el.value=""); });
    }

});

How to play YouTube video in my Android application?

You may use iframe as described in https://developers.google.com/youtube/iframe_api_reference

I am not following the google advises exactly but this is the code I am using and it is working fine

public class CWebVideoView {

    private String url;
    private Context context;
    private WebView webview;
    private static final String HTML_TEMPLATE = "webvideo.html";

    public CWebVideoView(Context context, WebView webview) {
        this.webview = webview;
        this.context = context;
        webview.setBackgroundColor(0);
        webview.getSettings().setJavaScriptEnabled(true);
    }

    public void load(String url){
        this.url = url;
        String data = readFromfile(HTML_TEMPLATE, context);
        data = data.replace("%1", url);
        webview.loadData(data, "text/html", "UTF-8");
    }

    public String readFromfile(String fileName, Context context) {
        StringBuilder returnString = new StringBuilder();
        InputStream fIn = null;
        InputStreamReader isr = null;
        BufferedReader input = null;
        try {
            fIn = context.getResources().getAssets().open(fileName, Context.MODE_WORLD_READABLE);
            isr = new InputStreamReader(fIn);
            input = new BufferedReader(isr);
            String line = "";
            while ((line = input.readLine()) != null) {
                returnString.append(line);
            }
        } catch (Exception e) {
            e.getMessage();
        } finally {
            try {
                if (isr != null)
                    isr.close();
                if (fIn != null)
                    fIn.close();
                if (input != null)
                    input.close();
            } catch (Exception e2) {
                e2.getMessage();
            }
        }
        return returnString.toString();
    }

    public void reload() {
        if (url!=null){
            load(url);
        }
    }
}

in /assets I have a file called webvideo.html

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="utf-8">
        <style>
            iframe   { border: 0; position:fixed; width:100%; height:100%; bgcolor="#000000"; }
            body     { margin: 0; bgcolor="#000000"; }
        </style>        
    </head>
    <body>
        <iframe src="%1" frameborder="0" allowfullscreen></iframe>
    </body>
</html>

and now I define a webview inside my main layout

<WebView
    android:id="@+id/video"
    android:visibility="gone"
    android:background="#000000"
    android:layout_centerInParent="true"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

and I use CWebVideoView inside my activity

videoView = (WebView) view.findViewById(R.id.video);
videoView.setVisibility(View.VISIBLE);
cWebVideoView = new CWebVideoView(context, videoView);
cWebVideoView.load(url);

Why use String.Format?

One reason it is not preferable to write the string like 'string +"Value"+ string' is because of Localization. In cases where localization is occurring we want the localized string to be correctly formatted, which could be very different from the language being coded in.

For example we need to show the following error in different languages:

MessageBox.Show(String.Format(ErrorManager.GetError("PIDV001").Description, proposalvalue.ProposalSource)

where

'ErrorCollector.GetError("ERR001").ErrorDescription' returns a string like "Your ID {0} is not valid". This message must be localized in many languages. In that case we can't use + in C#. We need to follow string.format.

Negative regex for Perl string pattern match

Your regex says the following:

/^         - if the line starts with
(          - start a capture group
Clinton|   - "Clinton" 
|          - or
[^Bush]    - Any single character except "B", "u", "s" or "h"
|          - or
Reagan)   - "Reagan". End capture group.
/i         - Make matches case-insensitive

So, in other words, your middle part of the regex is screwing you up. As it is a "catch-all" kind of group, it will allow any line that does not begin with any of the upper or lower case letters in "Bush". For example, these lines would match your regex:

Our president, George Bush
In the news today, pigs can fly
012-3123 33

You either make a negative look-ahead, as suggested earlier, or you simply make two regexes:

if( ($string =~ m/^(Clinton|Reagan)/i) and
    ($string !~ m/^Bush/i) ) {
   print "$string\n";
}

As mirod has pointed out in the comments, the second check is quite unnecessary when using the caret (^) to match only beginning of lines, as lines that begin with "Clinton" or "Reagan" could never begin with "Bush".

However, it would be valid without the carets.

Resize image proportionally with MaxHeight and MaxWidth constraints

Much longer solution, but accounts for the following scenarios:

Is the image smaller than the bounding box?
Is the Image and the Bounding Box square?
Is the Image square and the bounding box isn't
Is the image wider and taller than the bounding box
Is the image wider than the bounding box

Is the image taller than the bounding box

private Image ResizePhoto(FileInfo sourceImage, int desiredWidth, int desiredHeight)
{
    //throw error if bouning box is to small
    if (desiredWidth < 4 || desiredHeight < 4)
        throw new InvalidOperationException("Bounding Box of Resize Photo must be larger than 4X4 pixels.");            
    var original = Bitmap.FromFile(sourceImage.FullName);

    //store image widths in variable for easier use
    var oW = (decimal)original.Width;
    var oH = (decimal)original.Height;
    var dW = (decimal)desiredWidth;
    var dH = (decimal)desiredHeight;

    //check if image already fits
    if (oW < dW && oH < dH)
        return original; //image fits in bounding box, keep size (center with css) If we made it bigger it would stretch the image resulting in loss of quality.

    //check for double squares
    if (oW == oH && dW == dH)
    {
        //image and bounding box are square, no need to calculate aspects, just downsize it with the bounding box
        Bitmap square = new Bitmap(original, (int)dW, (int)dH);
        original.Dispose();
        return square;
    }

    //check original image is square
    if (oW == oH)
    {
        //image is square, bounding box isn't.  Get smallest side of bounding box and resize to a square of that center the image vertically and horizontally with Css there will be space on one side.
        int smallSide = (int)Math.Min(dW, dH);
        Bitmap square = new Bitmap(original, smallSide, smallSide);
        original.Dispose();
        return square;
    }

    //not dealing with squares, figure out resizing within aspect ratios            
    if (oW > dW && oH > dH) //image is wider and taller than bounding box
    {
        var r = Math.Min(dW, dH) / Math.Min(oW, oH); //two dimensions so figure out which bounding box dimension is the smallest and which original image dimension is the smallest, already know original image is larger than bounding box
        var nH = oH * r; //will downscale the original image by an aspect ratio to fit in the bounding box at the maximum size within aspect ratio.
        var nW = oW * r;
        var resized = new Bitmap(original, (int)nW, (int)nH);
        original.Dispose();
        return resized;
    }
    else
    {
        if (oW > dW) //image is wider than bounding box
        {
            var r = dW / oW; //one dimension (width) so calculate the aspect ratio between the bounding box width and original image width
            var nW = oW * r; //downscale image by r to fit in the bounding box...
            var nH = oH * r;
            var resized = new Bitmap(original, (int)nW, (int)nH);
            original.Dispose();
            return resized;
        }
        else
        {
            //original image is taller than bounding box
            var r = dH / oH;
            var nH = oH * r;
            var nW = oW * r;
            var resized = new Bitmap(original, (int)nW, (int)nH);
            original.Dispose();
            return resized;
        }
    }
}

Implements vs extends: When to use? What's the difference?

Both keywords are used when creating your own new class in the Java language.

Difference: implements means you are using the elements of a Java Interface in your class. extends means that you are creating a subclass of the base class you are extending. You can only extend one class in your child class, but you can implement as many interfaces as you would like.

Refer to oracle documentation page on interface for more details.

This can help to clarify what an interface is, and the conventions around using them.

Java JRE 64-bit download for Windows?

You can also just search on sites like Tucows and CNET, they have it there too.

SUM OVER PARTITION BY

remove partition by and add group by clause,

SELECT BrandId
      ,SUM(ICount) totalSum
  FROM Table 
WHERE DateId  = 20130618
GROUP BY BrandId

python date of the previous month

With the Pendulum very complete library, we have the subtract method (and not "subStract"):

import pendulum
today = pendulum.datetime.today()  # 2020, january
lastmonth = today.subtract(months=1)
lastmonth.strftime('%Y%m')
# '201912'

We see that it handles jumping years.

The reverse equivalent is add.

https://pendulum.eustace.io/docs/#addition-and-subtraction

LINQ orderby on date field in descending order

env.OrderByDescending(x => x.ReportDate)

phpmailer error "Could not instantiate mail function"

You need to make sure that your from address is a valid email account setup on that server.

Why do you use typedef when declaring an enum in C++?

This is kind of old, but anyway, I hope you'll appreciate the link that I am about to type as I appreciated it when I came across it earlier this year.

Here it is. I should quote the explanation that is always in my mind when I have to grasp some nasty typedefs:

In variable declarations, the introduced names are instances of the corresponding types. [...] However, when the typedef keyword precedes the declaration, the introduced names are aliases of the corresponding types

As many people previously said, there is no need to use typedefs declaring enums in C++. But that's the explanation of the typedef's syntax! I hope it helps (Probably not OP, since it's been almost 10 years, but anyone that is struggling to understand these kind of things).

Good ways to sort a queryset? - Django

I just wanted to illustrate that the built-in solutions (SQL-only) are not always the best ones. At first I thought that because Django's QuerySet.objects.order_by method accepts multiple arguments, you could easily chain them:

ordered_authors = Author.objects.order_by('-score', 'last_name')[:30]

But, it does not work as you would expect. Case in point, first is a list of presidents sorted by score (selecting top 5 for easier reading):

>>> auths = Author.objects.order_by('-score')[:5]
>>> for x in auths: print x
... 
James Monroe (487)
Ulysses Simpson (474)
Harry Truman (471)
Benjamin Harrison (467)
Gerald Rudolph (464)

Using Alex Martelli's solution which accurately provides the top 5 people sorted by last_name:

>>> for x in sorted(auths, key=operator.attrgetter('last_name')): print x
... 
Benjamin Harrison (467)
James Monroe (487)
Gerald Rudolph (464)
Ulysses Simpson (474)
Harry Truman (471)

And now the combined order_by call:

>>> myauths = Author.objects.order_by('-score', 'last_name')[:5]
>>> for x in myauths: print x
... 
James Monroe (487)
Ulysses Simpson (474)
Harry Truman (471)
Benjamin Harrison (467)
Gerald Rudolph (464)

As you can see it is the same result as the first one, meaning it doesn't work as you would expect.

Bash Shell Script - Check for a flag and grab its value

You should read this getopts tutorial.

Example with -a switch that requires an argument :

#!/bin/bash

while getopts ":a:" opt; do
  case $opt in
    a)
      echo "-a was triggered, Parameter: $OPTARG" >&2
      ;;
    \?)
      echo "Invalid option: -$OPTARG" >&2
      exit 1
      ;;
    :)
      echo "Option -$OPTARG requires an argument." >&2
      exit 1
      ;;
  esac
done

Like greybot said(getopt != getopts) :

The external command getopt(1) is never safe to use, unless you know it is GNU getopt, you call it in a GNU-specific way, and you ensure that GETOPT_COMPATIBLE is not in the environment. Use getopts (shell builtin) instead, or simply loop over the positional parameters.

How to view changes made to files on a certain revision in Subversion

Call this in the project:

svn diff -r REVNO:HEAD --summarize

REVNO is the start revision number and HEAD is the end revision number. If HEAD is equal to the last revision number, it can skip it.

The command returns a list with all files that are changed/added/deleted in this revision period.

The command can be called with the URL revision parameter to check changes like this:

svn diff -r REVNO:HEAD --summarize SVN_URL

No resource found that matches the given name '@style/Theme.AppCompat.Light'

The steps described above do work, however I've encountered this problem on IntelliJ IDEA and have found that I'm having these problems with existing projects and the only solution is to remove the 'appcompat' module (not the library) and re-import it.

Programs & Examples On #Aliasing

pip is not able to install packages correctly: Permission denied error

Debugging the error "gcc: error: x86_64-linux-gnu-gcc: No such file or directory"

java.lang.ClassNotFoundException: Didn't find class on path: dexpathlist

Change HTML email body font type and size in VBA

Installing PIL with pip

libpthread.so.0: error adding symbols: DSO missing from command line

HTML5 Canvas Resize (Downscale) Image High Quality?

How to apply font anti-alias effects in CSS?

How to increase IDE memory limit in IntelliJ IDEA on Mac?

How can I set a custom baud rate on Linux?

ld cannot find -l<library>

Webfont Smoothing and Antialiasing in Firefox and Opera

What is the difference between 'typedef' and 'using' in C++11?

Pip install Matplotlib error with virtualenv

How to install OpenSSL for Python

css transform, jagged edges in chrome

libxml install error using pip

HTML5 Canvas and Anti-aliasing

Forcing anti-aliasing using css: Is this a myth?

What is the strict aliasing rule?

Footnote

E: gnupg, gnupg2 and gnupg1 do not seem to be installed, but one of them is required for this operation

Fragment onCreateView and onActivityCreated called twice

Working with time DURATION, not time of day

"SSL certificate verify failed" using pip to install packages

Matching a space in regex

SQLAlchemy equivalent to SQL "LIKE" statement

Binding value to style

Open a new tab in the background?

How to check internet access on Android? InetAddress never times out

How to import an excel file in to a MySQL database

What is the difference between int, Int16, Int32 and Int64?

Rails: Can't verify CSRF token authenticity when making a POST request

Java math function to convert positive int to negative and negative to positive?

How do I Convert DateTime.now to UTC in Ruby?

read string from .resx file in C#

How do I localize the jQuery UI Datepicker?

CreateProcess error=206, The filename or extension is too long when running main() method

An object reference is required to access a non-static member

PHP 7 simpleXML

Convert SQL Server result set into string

AngularJS - Animate ng-view transitions

Array Size (Length) in C#

How to subtract a day from a date?

How to use workbook.saveas with automatic Overwrite

Clearing localStorage in javascript?

Force "portrait" orientation mode

WaitAll vs WhenAll

How to count digits, letters, spaces for a string in Python?

How to reset par(mfrow) in R

How to install mod_ssl for Apache httpd?

What JSON library to use in Scala?

Why are you not able to declare a class as static in Java?

Cannot deserialize the current JSON array (e.g. [1,2,3])

Why does .NET foreach loop throw NullRefException when collection is null?

Store select query's output in one array in postgres

Using numpy to build an array of all combinations of two arrays

Class constants in python

must declare a named package eclipse because this compilation unit is associated to the named module

Pass a String from one Activity to another Activity in Android

Cookies on localhost with explicit domain

How do you plot bar charts in gnuplot?

Passing variables through handlebars partial

Check for file exists or not in sql server?

"PKIX path building failed" and "unable to find valid certification path to requested target"

Mailbox unavailable. The server response was: 5.7.1 Unable to relay for [email protected]

Objective-C : BOOL vs bool

Copy array by value

Purpose of Unions in C and C++

Using BigDecimal to work with currencies

Python-equivalent of short-form "if" in C++

How to vertically align text in input type="text"?

How can strip whitespaces in PHP's variable?

Jersey client: How to add a list as query parameter

How to load a text file into a Hive table stored as sequence files

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

gcc-arm-linux-gnueabi command not found

Alternate background colors for list items

Single quotes vs. double quotes in Python

What is future in Python used for and how/when to use it, and how it works