Programs & Examples On #Desktop search

PHP $_SERVER['HTTP_HOST'] vs. $_SERVER['SERVER_NAME'], am I understanding the man pages correctly?

I am not sure and not really trust $_SERVER['HTTP_HOST'] because it depend on header from client. In another way, if a domain requested by client is not mine one, they will not getting into my site because DNS and TCP/IP protocol point it to the correct destination. However I don't know if possible to hijack the DNS, network or even Apache server. To be safe, I define host name in environment and compare it with $_SERVER['HTTP_HOST'].

Add SetEnv MyHost domain.com in .htaccess file on root and add ths code in Common.php

if (getenv('MyHost')!=$_SERVER['HTTP_HOST']) {
  header($_SERVER['SERVER_PROTOCOL'].' 400 Bad Request');
  exit();
}

I include this Common.php file in every php page. This page doing anything required for each request like session_start(), modify session cookie and reject if post method come from different domain.

Android SDK is missing, out of date, or is missing templates. Please ensure you are using SDK version 22 or later

I was able to trigger an SDK download like this:

  1. Close Android Studio
  2. Open android studio, but be ready
  3. Once you see "loading project", click cancel. (this will only appear for seconds on a fast machine)
  4. The SDK download window appeared!

Text Progress Bar in the Console

Write a \r to the console. That is a "carriage return" which causes all text after it to be echoed at the beginning of the line. Something like:

def update_progress(progress):
    print '\r[{0}] {1}%'.format('#'*(progress/10), progress)

which will give you something like: [ ########## ] 100%

UnicodeDecodeError when reading CSV file in Pandas with Python

Pandas allows to specify encoding, but does not allow to ignore errors not to automatically replace the offending bytes. So there is no one size fits all method but different ways depending on the actual use case.

  1. You know the encoding, and there is no encoding error in the file. Great: you have just to specify the encoding:

    file_encoding = 'cp1252'        # set file_encoding to the file encoding (utf8, latin1, etc.)
    pd.read_csv(input_file_and_path, ..., encoding=file_encoding)
    
  2. You do not want to be bothered with encoding questions, and only want that damn file to load, no matter if some text fields contain garbage. Ok, you only have to use Latin1 encoding because it accept any possible byte as input (and convert it to the unicode character of same code):

    pd.read_csv(input_file_and_path, ..., encoding='latin1')
    
  3. You know that most of the file is written with a specific encoding, but it also contains encoding errors. A real world example is an UTF8 file that has been edited with a non utf8 editor and which contains some lines with a different encoding. Pandas has no provision for a special error processing, but Python open function has (assuming Python3), and read_csv accepts a file like object. Typical errors parameter to use here are 'ignore' which just suppresses the offending bytes or (IMHO better) 'backslashreplace' which replaces the offending bytes by their Python’s backslashed escape sequence:

    file_encoding = 'utf8'        # set file_encoding to the file encoding (utf8, latin1, etc.)
    input_fd = open(input_file_and_path, encoding=file_encoding, errors = 'backslashreplace')
    pd.read_csv(input_fd, ...)
    

Adding Buttons To Google Sheets and Set value to Cells on clicking

Consider building an Add-on that has an actual button and not using the outdated method of linking an image to a script function.

In the script editor, under the Help menu >> Welcome Screen >> link to Google Sheets Add-on - will give you sample code to use.

How to change the bootstrap primary color?

Update 2020 for Bootstrap 4

To change the primary, or any of the theme colors in Bootstrap 4 SASS, set the appropriate variables before importing bootstrap.scss. This allows your custom scss to override the !default values...

$primary: purple;
$danger: red;

@import "bootstrap";

Demo: https://codeply.com/go/f5OmhIdre3


In some cases, you may want to set a new color from another existing Bootstrap variable. For this @import the functions and variables first so they can be referenced in the customizations...

/* import the necessary Bootstrap files */
@import "bootstrap/functions";
@import "bootstrap/variables";

$theme-colors: (
  primary: $purple
);

/* finally, import Bootstrap */
@import "bootstrap";

Demo: https://codeply.com/go/lobGxGgfZE


Also see: this answer, this answer or changing the button color in (CSS or SASS)


It's also possible to change the primary color with CSS only but it requires a lot of additional CSS since there are many -primary variations (btn-primary, alert-primary, bg-primary, text-primary, table-primary, border-primary, etc...) and some of these classes have slight colors variations on borders, hover, and active states. Therefore, if you must use CSS it's better to use target one component such as changing the primary button color.

These solutions will also work for Bootstrap 5 alpha

What does the ??!??! operator do in C?

??! is a trigraph that translates to |. So it says:

!ErrorHasOccured() || HandleError();

which, due to short circuiting, is equivalent to:

if (ErrorHasOccured())
    HandleError();

Guru of the Week (deals with C++ but relevant here), where I picked this up.

Possible origin of trigraphs or as @DwB points out in the comments it's more likely due to EBCDIC being difficult (again). This discussion on the IBM developerworks board seems to support that theory.

From ISO/IEC 9899:1999 §5.2.1.1, footnote 12 (h/t @Random832):

The trigraph sequences enable the input of characters that are not defined in the Invariant Code Set as described in ISO/IEC 646, which is a subset of the seven-bit US ASCII code set.

Putting images with options in a dropdown list

Checkout And Run The Following Code. It will help you...

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_x000D_
 $( function() {_x000D_
    $.widget( "custom.iconselectmenu", $.ui.selectmenu, {_x000D_
      _renderItem: function( ul, item ) {_x000D_
        var li = $( "<li>" ),_x000D_
          wrapper = $( "<div>", { text: item.label } );_x000D_
 _x000D_
        if ( item.disabled ) {_x000D_
          li.addClass( "ui-state-disabled" );_x000D_
        }_x000D_
 _x000D_
        $( "<span>", {_x000D_
          style: item.element.attr( "data-style" ),_x000D_
          "class": "ui-icon " + item.element.attr( "data-class" )_x000D_
        })_x000D_
          .appendTo( wrapper );_x000D_
 _x000D_
        return li.append( wrapper ).appendTo( ul );_x000D_
      }_x000D_
    });_x000D_
 _x000D_
    $( "#filesA" )_x000D_
      .iconselectmenu()_x000D_
      .iconselectmenu( "menuWidget" )_x000D_
        .addClass( "ui-menu-icons" );_x000D_
 _x000D_
    $( "#filesB" )_x000D_
      .iconselectmenu()_x000D_
      .iconselectmenu( "menuWidget" )_x000D_
        .addClass( "ui-menu-icons customicons" );_x000D_
 _x000D_
    $( "#people" )_x000D_
      .iconselectmenu()_x000D_
      .iconselectmenu( "menuWidget")_x000D_
        .addClass( "ui-menu-icons avatar" );_x000D_
  } );_x000D_
  </script>_x000D_
  <style>_x000D_
    h2 {_x000D_
      margin: 30px 0 0 0;_x000D_
    }_x000D_
    fieldset {_x000D_
      border: 0;_x000D_
    }_x000D_
    label
_x000D_
{_x000D_
      display: block;_x000D_
    }_x000D_
 _x000D_
    /* select with custom icons */_x000D_
    .ui-selectmenu-menu .ui-menu.customicons .ui-menu-item-wrapper {_x000D_
      padding: 0.5em 0 0.5em 3em;_x000D_
    }_x000D_
    .ui-selectmenu-menu .ui-menu.customicons .ui-menu-item .ui-icon {_x000D_
      height: 24px;_x000D_
      width: 24px;_x000D_
      top: 0.1em;_x000D_
    }_x000D_
    .ui-icon.video {_x000D_
      background: url("images/24-video-square.png") 0 0 no-repeat;_x000D_
    }_x000D_
    .ui-icon.podcast {_x000D_
      background: url("images/24-podcast-square.png") 0 0 no-repeat;_x000D_
    }_x000D_
    .ui-icon.rss {_x000D_
      background: url("images/24-rss-square.png") 0 0 no-repeat;_x000D_
    }_x000D_
 _x000D_
    /* select with CSS avatar icons */_x000D_
    option.avatar {_x000D_
      background-repeat: no-repeat !important;_x000D_
      padding-left: 20px;_x000D_
    }_x000D_
    .avatar .ui-icon {_x000D_
      background-position: left top;_x000D_
    }
_x000D_
<link href="//code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css" rel="stylesheet"/>_x000D_
<script src="https://code.jquery.com/jquery-1.12.4.js"></script>_x000D_
<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>_x000D_
<!doctype html>_x000D_
<html lang="en">_x000D_
<head>_x000D_
  <meta charset="utf-8">_x000D_
  <meta name="viewport" content="width=device-width, initial-scale=1">_x000D_
  <title>jQuery UI Selectmenu - Custom Rendering</title>_x000D_
  _x000D_
</head>_x000D_
<body>_x000D_
 _x000D_
<div class="demo">_x000D_
 _x000D_
<form action="#">_x000D_
  <h2>Selectmenu with framework icons</h2>_x000D_
  <fieldset>_x000D_
    <label for="filesA">Select a File:</label>_x000D_
    <select name="filesA" id="filesA">_x000D_
      <option value="jquery" data-class="ui-icon-script">jQuery.js</option>_x000D_
      <option value="jquerylogo" data-class="ui-icon-image">jQuery Logo</option>_x000D_
      <option value="jqueryui" data-class="ui-icon-script">ui.jQuery.js</option>_x000D_
      <option value="jqueryuilogo" selected="selected" data-class="ui-icon-image">jQuery UI Logo</option>_x000D_
      <option value="somefile" disabled="disabled" data-class="ui-icon-help">Some unknown file</option>_x000D_
    </select>_x000D_
  </fieldset>_x000D_
 _x000D_
  <h2>Selectmenu with custom icon images</h2>_x000D_
  <fieldset>_x000D_
    <label for="filesB">Select a podcast:</label>_x000D_
    <select name="filesB" id="filesB">_x000D_
      <option value="mypodcast" data-class="podcast">John Resig Podcast</option>_x000D_
      <option value="myvideo" data-class="video">Scott González Video</option>_x000D_
      <option value="myrss" data-class="rss">jQuery RSS XML</option>_x000D_
    </select>_x000D_
  </fieldset>_x000D_
 _x000D_
  <h2>Selectmenu with custom avatar 16x16 images as CSS background</h2>_x000D_
  <fieldset>_x000D_
    <label for="people">Select a Person:</label>_x000D_
    <select name="people" id="people">_x000D_
      <option value="1" data-class="avatar" data-style="background-image: url(&apos;http://www.gravatar.com/avatar/b3e04a46e85ad3e165d66f5d927eb609?d=monsterid&amp;r=g&amp;s=16&apos;);">John Resig</option>_x000D_
      <option value="2" data-class="avatar" data-style="background-image: url(&apos;http://www.gravatar.com/avatar/e42b1e5c7cfd2be0933e696e292a4d5f?d=monsterid&amp;r=g&amp;s=16&apos;);">Tauren Mills</option>_x000D_
      <option value="3" data-class="avatar" data-style="background-image: url(&apos;http://www.gravatar.com/avatar/bdeaec11dd663f26fa58ced0eb7facc8?d=monsterid&amp;r=g&amp;s=16&apos;);">Jane Doe</option>_x000D_
    </select>_x000D_
  </fieldset>_x000D_
</form>_x000D_
 _x000D_
</div>_x000D_
 _x000D_
 _x000D_
</body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

WPF Data Binding and Validation Rules Best Practices

If your business class is directly used by your UI is preferrable to use IDataErrorInfo because it put logic closer to their owner.

If your business class is a stub class created by a reference to an WCF/XmlWeb service then you can not/must not use IDataErrorInfo nor throw Exception for use with ExceptionValidationRule. Instead you can:

  • Use custom ValidationRule.
  • Define a partial class in your WPF UI project and implements IDataErrorInfo.

Oracle ORA-12154: TNS: Could not resolve service name Error?

This error message can be very confusing and the solution can be surprisingly primitive.

In my case: Oracle stored procedure sends recordset to MS Excel via "Provider=OraOLEDB.Oracle;Data Source= ...etc" .

The problem was a number of decimal numbers in the Oracle data column sent to Excel 2010. When I used Oracle SQL query ROUND(grosssales_eur,2) AS grosssales_eur, it worked fine.

how to change class name of an element by jquery

$('.IsBestAnswer').addClass('bestanswer').removeClass('IsBestAnswer');

Case in method names is important, so no addclass.

jQuery addClass()
jQuery removeClass()

RecyclerView and java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder in Samsung devices

This happens when you specify the incorrect position for the notifyItemChanged , notifyItemRangeInserted etc.For me :

Before : (Erroneous)

public void addData(List<ChannelItem> list) {
  int initialSize = list.size();
  mChannelItemList.addAll(list);
  notifyItemRangeChanged(initialSize - 1, mChannelItemList.size());
 } 

After : (Correct)

 public void addData(List<ChannelItem> list) {
  int initialSize = mChannelItemList.size();
  mChannelItemList.addAll(list);
  notifyItemRangeInserted(initialSize, mChannelItemList.size()-1); //Correct position 
 }

What is the incentive for curl to release the library for free?

I'm Daniel Stenberg.

I made curl

I founded the curl project back in 1998, I wrote the initial curl version and I created libcurl. I've written more than half of all the 24,000 commits done in the source code repository up to this point in time. I'm still the lead developer of the project. To a large extent, curl is my baby.

I shipped the first version of curl as open source since I wanted to "give back" to the open source world that had given me so much code already. I had used so much open source and I wanted to be as cool as the other open source authors.

Thanks to it being open source, literally thousands of people have been able to help us out over the years and have improved the products, the documentation. the web site and just about every other detail around the project. curl and libcurl would never have become the products that they are today were they not open source. The list of contributors now surpass 1900 names and currently the list grows with a few hundred names per year.

Thanks to curl and libcurl being open source and liberally licensed, they were immediately adopted in numerous products and soon shipped by operating systems and Linux distributions everywhere thus getting a reach beyond imagination.

Thanks to them being "everywhere", available and liberally licensed they got adopted and used everywhere and by everyone. It created a defacto transfer library standard.

At an estimated six billion installations world wide, we can safely say that curl is the most widely used internet transfer library in the world. It simply would not have gone there had it not been open source. curl runs in billions of mobile phones, a billion Windows 10 installations, in a half a billion games and several hundred million TVs - and more.

Should I have released it with proprietary license instead and charged users for it? It never occured to me, and it wouldn't have worked because I would never had managed to create this kind of stellar project on my own. And projects and companies wouldn't have used it.

Why do I still work on curl?

Now, why do I and my fellow curl developers still continue to develop curl and give it away for free to the world?

  1. I can't speak for my fellow project team members. We all participate in this for our own reasons.
  2. I think it's still the right thing to do. I'm proud of what we've accomplished and I truly want to make the world a better place and I think curl does its little part in this.
  3. There are still bugs to fix and features to add!
  4. curl is free but my time is not. I still have a job and someone still has to pay someone for me to get paid every month so that I can put food on the table for my family. I charge customers and companies to help them with curl. You too can get my help for a fee, which then indirectly helps making sure that curl continues to evolve, remain free and the kick-ass product it is.
  5. curl was my spare time project for twenty years before I started working with it full time. I've had great jobs and worked on awesome projects. I've been in a position of luxury where I could continue to work on curl on my spare time and keep shipping a quality product for free. My work on curl has given me friends, boosted my career and taken me to places I would not have been at otherwise.
  6. I would not do it differently if I could back and do it again.

Am I proud of what we've done?

Yes. So insanely much.

But I'm not satisfied with this and I'm not just leaning back, happy with what we've done. I keep working on curl every single day, to improve, to fix bugs, to add features and to make sure curl keeps being the number one file transfer solution for the world even going forward.

We do mistakes along the way. We make the wrong decisions and sometimes we implement things in crazy ways. But to win in the end and to conquer the world is about patience and endurance and constantly going back and reconsidering previous decisions and correcting previous mistakes. To continuously iterate, polish off rough edges and gradually improve over time.

Never give in. Never stop. Fix bugs. Add features. Iterate. To the end of time.

For real?

Yeah. For real.

Do I ever get tired? Is it ever done?

Sure I get tired at times. Working on something every day for over twenty years isn't a paved downhill road. Sometimes there are obstacles. During times things are rough. Occasionally people are just as ugly and annoying as people can be.

But curl is my life's project and I have patience. I have thick skin and I don't give up easily. The tough times pass and most days are awesome. I get to hang out with awesome people and the reward is knowing that my code helps driving the Internet revolution everywhere is an ego boost above normal.

curl will never be "done" and so far I think work on curl is pretty much the most fun I can imagine. Yes, I still think so even after twenty years in the driver's seat. And as long as I think it's fun I intend to keep at it.

How to create a localhost server to run an AngularJS project

If you have used Visual Studio Community or any other edition for your angular project , then go to the project folder , first type

C:\Project Folder>npm install -g http-server You will see as follows: + [email protected] added 25 packages in 4.213s

Then type C:\Project Folder>http-server –o

You will see that your application automatically comes up at http://127.0.0.1:8080/

How to sort pandas data frame using values from several columns?

Use of sort can result in warning message. See github discussion. So you might wanna use sort_values, docs here

Then your code can look like this:

df = df.sort_values(by=['c1','c2'], ascending=[False,True])

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

Based on @ford04 answer, here is the same encapsulated in a method :

import React, { FC, useState, useEffect, DependencyList } from 'react';

export function useEffectAsync( effectAsyncFun : ( isMounted: () => boolean ) => unknown, deps?: DependencyList ) {
    useEffect( () => {
        let isMounted = true;
        const _unused = effectAsyncFun( () => isMounted );
        return () => { isMounted = false; };
    }, deps );
} 

Usage:

const MyComponent : FC<{}> = (props) => {
    const [ asyncProp , setAsyncProp ] = useState( '' ) ;
    useEffectAsync( async ( isMounted ) =>
    {
        const someAsyncProp = await ... ;
        if ( isMounted() )
             setAsyncProp( someAsyncProp ) ;
    });
    return <div> ... ;
} ;

How to downgrade the installed version of 'pip' on windows?

pip itself is just a normal python package. Thus you can install pip with pip.

Of cource, you don't want to affect the system's pip, install it inside a virtualenv.

pip install pip==1.2.1

Converting between datetime, Timestamp and datetime64

To convert numpy.datetime64 to datetime object that represents time in UTC on numpy-1.8:

>>> from datetime import datetime
>>> import numpy as np
>>> dt = datetime.utcnow()
>>> dt
datetime.datetime(2012, 12, 4, 19, 51, 25, 362455)
>>> dt64 = np.datetime64(dt)
>>> ts = (dt64 - np.datetime64('1970-01-01T00:00:00Z')) / np.timedelta64(1, 's')
>>> ts
1354650685.3624549
>>> datetime.utcfromtimestamp(ts)
datetime.datetime(2012, 12, 4, 19, 51, 25, 362455)
>>> np.__version__
'1.8.0.dev-7b75899'

The above example assumes that a naive datetime object is interpreted by np.datetime64 as time in UTC.


To convert datetime to np.datetime64 and back (numpy-1.6):

>>> np.datetime64(datetime.utcnow()).astype(datetime)
datetime.datetime(2012, 12, 4, 13, 34, 52, 827542)

It works both on a single np.datetime64 object and a numpy array of np.datetime64.

Think of np.datetime64 the same way you would about np.int8, np.int16, etc and apply the same methods to convert beetween Python objects such as int, datetime and corresponding numpy objects.

Your "nasty example" works correctly:

>>> from datetime import datetime
>>> import numpy 
>>> numpy.datetime64('2002-06-28T01:00:00.000000000+0100').astype(datetime)
datetime.datetime(2002, 6, 28, 0, 0)
>>> numpy.__version__
'1.6.2' # current version available via pip install numpy

I can reproduce the long value on numpy-1.8.0 installed as:

pip install git+https://github.com/numpy/numpy.git#egg=numpy-dev

The same example:

>>> from datetime import datetime
>>> import numpy
>>> numpy.datetime64('2002-06-28T01:00:00.000000000+0100').astype(datetime)
1025222400000000000L
>>> numpy.__version__
'1.8.0.dev-7b75899'

It returns long because for numpy.datetime64 type .astype(datetime) is equivalent to .astype(object) that returns Python integer (long) on numpy-1.8.

To get datetime object you could:

>>> dt64.dtype
dtype('<M8[ns]')
>>> ns = 1e-9 # number of seconds in a nanosecond
>>> datetime.utcfromtimestamp(dt64.astype(int) * ns)
datetime.datetime(2002, 6, 28, 0, 0)

To get datetime64 that uses seconds directly:

>>> dt64 = numpy.datetime64('2002-06-28T01:00:00.000000000+0100', 's')
>>> dt64.dtype
dtype('<M8[s]')
>>> datetime.utcfromtimestamp(dt64.astype(int))
datetime.datetime(2002, 6, 28, 0, 0)

The numpy docs say that the datetime API is experimental and may change in future numpy versions.

Xamarin 2.0 vs Appcelerator Titanium vs PhoneGap

There's also AppGyver Steroids that unites PhoneGap and Native UI nicely.

With Steroids you can add things like native tabs, native navigation bar, native animations and transitions, native modal windows, native drawer/panel (facebooks side menu) etc. to your PhoneGap app.

Here's a demo: http://youtu.be/oXWwDMdoTCk?t=20m17s

What GRANT USAGE ON SCHEMA exactly do?

GRANTs on different objects are separate. GRANTing on a database doesn't GRANT rights to the schema within. Similiarly, GRANTing on a schema doesn't grant rights on the tables within.

If you have rights to SELECT from a table, but not the right to see it in the schema that contains it then you can't access the table.

The rights tests are done in order:

Do you have `USAGE` on the schema? 
    No:  Reject access. 
    Yes: Do you also have the appropriate rights on the table? 
        No:  Reject access. 
        Yes: Check column privileges.

Your confusion may arise from the fact that the public schema has a default GRANT of all rights to the role public, which every user/group is a member of. So everyone already has usage on that schema.

The phrase:

(assuming that the objects' own privilege requirements are also met)

Is saying that you must have USAGE on a schema to use objects within it, but having USAGE on a schema is not by itself sufficient to use the objects within the schema, you must also have rights on the objects themselves.

It's like a directory tree. If you create a directory somedir with file somefile within it then set it so that only your own user can access the directory or the file (mode rwx------ on the dir, mode rw------- on the file) then nobody else can list the directory to see that the file exists.

If you were to grant world-read rights on the file (mode rw-r--r--) but not change the directory permissions it'd make no difference. Nobody could see the file in order to read it, because they don't have the rights to list the directory.

If you instead set rwx-r-xr-x on the directory, setting it so people can list and traverse the directory but not changing the file permissions, people could list the file but could not read it because they'd have no access to the file.

You need to set both permissions for people to actually be able to view the file.

Same thing in Pg. You need both schema USAGE rights and object rights to perform an action on an object, like SELECT from a table.

(The analogy falls down a bit in that PostgreSQL doesn't have row-level security yet, so the user can still "see" that the table exists in the schema by SELECTing from pg_class directly. They can't interact with it in any way, though, so it's just the "list" part that isn't quite the same.)

How to install packages offline?

Let me go through the process step by step:

  1. On a computer connected to the internet, create a folder.
   $ mkdir packages
   $ cd packages
  1. open up a command prompt or shell and execute the following command:

    Suppose the package you want is tensorflow

    $ pip download tensorflow

  2. Now, on the target computer, copy the packages folder and apply the following command

  $ cd packages
  $ pip install 'tensorflow-xyz.whl' --no-index --find-links '.'

Note that the tensorflow-xyz.whl must be replaced by the original name of the required package.

How to create windows service from java jar?

[2020 Update]

Actually, after spending some times trying the different option provided here which are quite old, I found that the easiest way to do it was to use a small paid tool built for that purpose : FireDaemon Pro. I was trying to run Selenium standalone server as a service and none of the free option worked instantly.

The tool is quite cheap (50 USD one-time-licence, 30 days trial) and it took me 5 minutes to set up the server service instead of a half a day of reading/troubleshooting. So far, it works like a charm.

I have absolutely no link with FusionPro, this is a pure disinterested advice, but feel free to delete if it violates forum rules.

How to compile makefile using MinGW?

You have to actively choose to install MSYS to get the make.exe. So you should always have at least (the native) mingw32-make.exe if MinGW was installed properly. And if you installed MSYS you will have make.exe (in the MSYS subfolder probably).

Note that many projects require first creating a makefile (e.g. using a configure script or automake .am file) and it is this step that requires MSYS or cygwin. Makes you wonder why they bothered to distribute the native make at all.

Once you have the makefile, it is unclear if the native executable requires a different path separator than the MSYS make (forward slashes vs backward slashes). Any autogenerated makefile is likely to have unix-style paths, assuming the native make can handle those, the compiled output should be the same.

Django Rest Framework File Upload

Finally I am able to upload image using Django. Here is my working code

views.py

class FileUploadView(APIView):
    parser_classes = (FileUploadParser, )

    def post(self, request, format='jpg'):
        up_file = request.FILES['file']
        destination = open('/Users/Username/' + up_file.name, 'wb+')
        for chunk in up_file.chunks():
            destination.write(chunk)
        destination.close()  # File should be closed only after all chuns are added

        # ...
        # do some stuff with uploaded file
        # ...
        return Response(up_file.name, status.HTTP_201_CREATED)

urls.py

urlpatterns = patterns('', 
url(r'^imageUpload', views.FileUploadView.as_view())

curl request to upload

curl -X POST -S -H -u "admin:password" -F "[email protected];type=image/jpg" 127.0.0.1:8000/resourceurl/imageUpload

Select statement to find duplicates on certain fields

Try this query to find duplicate records on multiple fields

SELECT a.column1, a.column2
FROM dbo.a a
JOIN (SELECT column1, 
       column2, count(*) as countC
FROM dbo.a 
GROUP BY column4, column5
HAVING count(*) > 1 ) b
ON a.column1 = b.column1
AND a.column2 = b.column2

How do I show the value of a #define at compile-time?

If you are using Visual C++, you can use #pragma message:

#include <boost/preprocessor/stringize.hpp>
#pragma message("BOOST_VERSION=" BOOST_PP_STRINGIZE(BOOST_VERSION))

Edit: Thanks to LB for link

Apparently, the GCC equivalent is (not tested):

#pragma message "BOOST_VERSION=" BOOST_PP_STRINGIZE(BOOST_VERSION)

how to define ssh private key for servers fetched by dynamic inventory in files

I had a similar issue and solved it with a patch to ec2.py and adding some configuration parameters to ec2.ini. The patch takes the value of ec2_key_name, prefixes it with the ssh_key_path, and adds the ssh_key_suffix to the end, and writes out ansible_ssh_private_key_file as this value.

The following variables have to be added to ec2.ini in a new 'ssh' section (this is optional if the defaults match your environment):

[ssh]
# Set the path and suffix for the ssh keys
ssh_key_path = ~/.ssh
ssh_key_suffix = .pem

Here is the patch for ec2.py:

204a205,206
>     'ssh_key_path': '~/.ssh',
>     'ssh_key_suffix': '.pem',
422a425,428
>         # SSH key setup
>         self.ssh_key_path = os.path.expanduser(config.get('ssh', 'ssh_key_path'))
>         self.ssh_key_suffix = config.get('ssh', 'ssh_key_suffix')
> 
1490a1497
>         instance_vars["ansible_ssh_private_key_file"] = os.path.join(self.ssh_key_path, instance_vars["ec2_key_name"] + self.ssh_key_suffix)

What is the difference between children and childNodes in JavaScript?

Good answers so far, I want to only add that you could check the type of a node using nodeType:

yourElement.nodeType

This will give you an integer: (taken from here)

| Value |             Constant             |                          Description                          |  |
|-------|----------------------------------|---------------------------------------------------------------|--|
|    1  | Node.ELEMENT_NODE                | An Element node such as <p> or <div>.                         |  |
|    2  | Node.ATTRIBUTE_NODE              | An Attribute of an Element. The element attributes            |  |
|       |                                  | are no longer implementing the Node interface in              |  |
|       |                                  | DOM4 specification.                                           |  |
|    3  | Node.TEXT_NODE                   | The actual Text of Element or Attr.                           |  |
|    4  | Node.CDATA_SECTION_NODE          | A CDATASection.                                               |  |
|    5  | Node.ENTITY_REFERENCE_NODE       | An XML Entity Reference node. Removed in DOM4 specification.  |  |
|    6  | Node.ENTITY_NODE                 | An XML <!ENTITY ...> node. Removed in DOM4 specification.     |  |
|    7  | Node.PROCESSING_INSTRUCTION_NODE | A ProcessingInstruction of an XML document                    |  |
|       |                                  | such as <?xml-stylesheet ... ?> declaration.                  |  |
|    8  | Node.COMMENT_NODE                | A Comment node.                                               |  |
|    9  | Node.DOCUMENT_NODE               | A Document node.                                              |  |
|   10  | Node.DOCUMENT_TYPE_NODE          | A DocumentType node e.g. <!DOCTYPE html> for HTML5 documents. |  |
|   11  | Node.DOCUMENT_FRAGMENT_NODE      | A DocumentFragment node.                                      |  |
|   12  | Node.NOTATION_NODE               | An XML <!NOTATION ...> node. Removed in DOM4 specification.   |  |

Note that according to Mozilla:

The following constants have been deprecated and should not be used anymore: Node.ATTRIBUTE_NODE, Node.ENTITY_REFERENCE_NODE, Node.ENTITY_NODE, Node.NOTATION_NODE

What causes: "Notice: Uninitialized string offset" to appear?

This error would occur if any of the following variables were actually strings or null instead of arrays, in which case accessing them with an array syntax $var[$i] would be like trying to access a specific character in a string:

$catagory
$task
$fullText
$dueDate
$empId

In short, everything in your insert query.

Perhaps the $catagory variable is misspelled?

Deploying my application at the root in Tomcat

You have a couple of options:

  1. Remove the out-of-the-box ROOT/ directory from tomcat and rename your war file to ROOT.war before deploying it.

  2. Deploy your war as (from your example) war_name.war and configure the context root in conf/server.xml to use your war file :

    <Context path="" docBase="war_name" debug="0" reloadable="true"></Context>
    

The first one is easier, but a little more kludgy. The second one is probably the more elegant way to do it.

jQuery Screen Resolution Height Adjustment

Another example for vertically and horizontally centered div or any object(s):

 var obj = $("#divID");
 var halfsc = $(window).height()/2;
 var halfh = $(obj).height() / 2; 

 var halfscrn = screen.width/2;
 var halfobj =$(obj).width() / 2; 

 var goRight =  halfscrn - halfobj ;
 var goBottom = halfsc - halfh;

 $(obj).css({marginLeft: goRight }).css({marginTop: goBottom });

"Call to undefined function mysql_connect()" after upgrade to php-7

From the PHP Manual:

Warning This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide. Alternatives to this function include:

mysqli_connect()

PDO::__construct()

use MySQLi or PDO

<?php
$con = mysqli_connect('localhost', 'username', 'password', 'database');

Can inner classes access private variables?

First of all, you are trying to access non-static member var outside the class which is not allowed in C++.

Mark's answer is correct.

Anything that is part of Outer should have access to all of Outer's members, public or private.

So you can do two things, either declare var as static or use a reference of an instance of the outer class to access 'var' (because a friend class or function also needs reference to access private data).

Static var

Change var to static If you don't want var to be associated with the instances of the class.

#include <iostream>

class Outer {

private:
    static const char* const MYCONST;
    static int var;

public:
   class Inner {
    public:
        Inner() {
          Outer::var = 1;
        }
        void func() ;
    };
};

int Outer::var = 0;

void Outer::Inner::func() {
    std::cout << "var: "<< Outer::var;
}

int main() {
  Outer outer;
  Outer::Inner inner;
  inner.func();

}

Output- var: 1

Non-static var

An object's reference is must access any non-static member variables.

#include <iostream>

class Outer {

private:
    static const char* const MYCONST;
    int var;

public:
   class Inner {
    public:
        Inner(Outer &outer) {
          outer.var = 1;
        }
        void func(const Outer &outer) ;
    };
};

void Outer::Inner::func(const Outer &outer) {
    std::cout << "var: "<< outer.var;
}

int main() {
  Outer outer;
  Outer::Inner inner(outer);
  inner.func(outer);

}

Output- var: 1

Edit - External links are links to my Blog.

Create line after text with css

You could achieve this with an extra <span>:

HTML

<h2><span>Featured products</span></h2>
<h2><span>Here is a very long h2, and as you can see the line get too wide</span></h2>

CSS

h2 {
    position: relative;
}

h2 span {
    background-color: white;
    padding-right: 10px;
}

h2:after {
    content:"";
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 0.5em;
    border-top: 1px solid black;
    z-index: -1;
}

http://jsfiddle.net/myajouri/pkm5r/

Another solution without the extra <span> but requires an overflow: hidden on the <h2>:

h2 {
    overflow: hidden;
}

h2:after {
    content:"";
    display: inline-block;
    height: 0.5em;
    vertical-align: bottom;
    width: 100%;
    margin-right: -100%;
    margin-left: 10px;
    border-top: 1px solid black;
}

http://jsfiddle.net/myajouri/h2JRj/

Node Express sending image files as API response

a proper solution with streams and error handling is below:

const fs = require('fs')
const stream = require('stream')

app.get('/report/:chart_id/:user_id',(req, res) => {
  const r = fs.createReadStream('path to file') // or any other way to get a readable stream
  const ps = new stream.PassThrough() // <---- this makes a trick with stream error handling
  stream.pipeline(
   r,
   ps, // <---- this makes a trick with stream error handling
   (err) => {
    if (err) {
      console.log(err) // No such file or any other kind of error
      return res.sendStatus(400); 
    }
  })
  ps.pipe(res) // <---- this makes a trick with stream error handling
})

with Node older then 10 you will need to use pump instead of pipeline.

Compiling with g++ using multiple cores

People have mentioned make but bjam also supports a similar concept. Using bjam -jx instructs bjam to build up to x concurrent commands.

We use the same build scripts on Windows and Linux and using this option halves our build times on both platforms. Nice.

Prevent form submission on Enter key press

So maybe the best solution to cover as many browsers as possible and be future proof would be

if (event.which === 13 || event.keyCode === 13 || event.key === "Enter")

Javascript Array Alert

If you want to see the array as an array, you can say

alert(JSON.stringify(aCustomers));

instead of all those document.writes.

http://jsfiddle.net/5b2eb/

However, if you want to display them cleanly, one per line, in your popup, do this:

alert(aCustomers.join("\n"));

http://jsfiddle.net/5b2eb/1/

Redirect all to index.php using htaccess

There is one "trick" for this problem that fits all scenarios, a so obvious solution that you will have to try it to believe it actually works... :)

Here it is...

<IfModule mod_rewrite.c>

   RewriteEngine On

   RewriteCond %{REQUEST_FILENAME}  -f [OR]
   RewriteCond %{REQUEST_FILENAME} !-f
   RewriteRule ^(.*)$ index.php [L,QSA]

</IfModule>

Basically, you are asking MOD_REWRITE to forward to index.php the URI request always when a file exists AND always when the requested file doesn't exist!

When investigating the source code of MOD-REWRITE to understand how it works I realized that all its checks always happen after the verification if the referenced file exists or not. Only then the RegEx are processed. Even when your URI points to a folder, Apache will enforce the check for the index files listed in its configuration file.

Based on that simple discovery, turned obvious a simple file validation would be enough for all possible calls, as far as we double-tap the file presence check and route both results to the same end-point, covering 100% of the possibilities.

IMPORTANT: Notice there is no "/" in index.php. By default, MOD_REWRITE will use the folder it is set as "base folder" for the forwarding. The beauty of it is that it doesn't necessarily need to be the "root folder" of the site, allowing this solution work for localhost/ and/or any subfolder you apply it.

Ultimately, some other solutions I tested before (the ones that appeared to be working fine) broke the PHP ability to "require" a file via its relative path, which is a bummer. Be careful.

Some people may say this is an inelegant solution. It may be, actually, but as far as tests, in several scenarios, several servers, several different Apache versions, etc., this solution worked 100% on all cases!

Can we define min-margin and max-margin, max-padding and min-padding in css?

margin and padding don't have min or max prefixes. Sometimes you can try to specify margin and padding in terms of percentage to make it variable with respect to screen size.

Further you can also use min-width, max-width, min-height and max-height for doing the similar things.

Hope it helps.

CAST to DECIMAL in MySQL

An alternative, I think for your purpose, is to use the round() function:

select round((10 * 1.5),2) // prints 15.00

You can try it here:

Xpath for href element

Try below locator.

selenium.click("css=a[href*='listDetails.do'][id='oldcontent']");

or

selenium.click("xpath=//a[contains(@href,'listDetails.do') and @id='oldcontent']");

Color theme for VS Code integrated terminal

You can actually modify your user settings and edit each colour individually by adding the following to the user settings.

  1. Open user settings (ctrl + ,)
  2. Search for workbench and select Edit in settings.json under Color Customizations
"workbench.colorCustomizations" : {
    "terminal.foreground" : "#00FD61",
    "terminal.background" : "#383737"
}

For more on what colors you can edit you can find out here.

How to loop through all the files in a directory in c # .net?

You can have a look at this page showing Deep Folder Copy, it uses recursive means to iterate throught the files and has some really nice tips, like filtering techniques etc.

http://www.codeproject.com/Tips/512208/Folder-Directory-Deep-Copy-including-sub-directori

Laravel 5 Eloquent where and or in Clauses

When we use multiple and (where) condition with last (where + or where) the where condition fails most of the time. for that we can use the nested where function with parameters passing in that.

$feedsql = DB::table('feeds as t1')
                   ->leftjoin('groups as t2', 't1.groups_id', '=', 't2.id')
                    ->where('t2.status', 1)
                    ->whereRaw("t1.published_on <= NOW()") 
                    >whereIn('t1.groupid', $group_ids)
                   ->where(function($q)use ($userid) {
                            $q->where('t2.contact_users_id', $userid)
                            ->orWhere('t1.users_id', $userid);
                     })
                  ->orderBy('t1.published_on', 'desc')->get();

The above query validate all where condition then finally checks where t2.status=1 and (where t2.contact_users_id='$userid' or where t1.users_id='$userid')

Get latitude and longitude automatically using php, API

//add urlencode to your address
$address = urlencode("technopark, Trivandrun, kerala,India");
$region = "IND";
$json = file_get_contents("http://maps.google.com/maps/api/geocode/json?address=$address&sensor=false&region=$region");

echo $json;

$decoded = json_decode($json);

print_r($decoded);

No Activity found to handle Intent : android.intent.action.VIEW

First try this code inside AndroidManifest

  <application>
       
    <uses-library
        android:name="org.apache.http.legacy"
        android:required="false" />
 </application>

If this code works, so fine. But if not. Try this code from which class you want to pass the data or uri.

Intent window = new Intent(getApplicationContext(), Browser.class);
window.putExtra("LINK", "http://www.yourwebsite.com");
startActivity(window);

How to check the differences between local and github before the pull

If you're not interested in the details that git diff outputs you can just run git cherry which will output a list of commits your remote tracking branch has ahead of your local branch.

For example:

git fetch origin
git cherry master origin/master

Will output something like :

+ 2642039b1a4c4d4345a0d02f79ccc3690e19d9b1
+ a4870f9fbde61d2d657e97b72b61f46d1fd265a9

Indicates that there are two commits in my remote tracking branch that haven't been merged into my local branch.

This also works the other way :

    git cherry origin/master master

Will show you a list of local commits that you haven't pushed to your remote repository yet.

Difference between @click and v-on:click Vuejs

There is no difference between the two, one is just a shorthand for the second.

The v- prefix serves as a visual cue for identifying Vue-specific attributes in your templates. This is useful when you are using Vue.js to apply dynamic behavior to some existing markup, but can feel verbose for some frequently used directives. At the same time, the need for the v- prefix becomes less important when you are building an SPA where Vue.js manages every template.

<!-- full syntax -->
<a v-on:click="doSomething"></a>
<!-- shorthand -->
<a @click="doSomething"></a>

Source: official documentation.

How to list the properties of a JavaScript object?

With ES6 and later (ECMAScript 2015), you can get all properties like this:

let keys = Object.keys(myObject);

And if you wanna list out all values:

let values = Object.keys(myObject).map(key => myObject[key]);

Textarea Auto height

I see that this is answered already, but I believe I have a simple jQuery solution ( jQuery is not even really needed; I just enjoy using it ):

I suggest counting the line breaks in the textarea text and setting the rows attribute of the textarea accordingly.

var text = jQuery('#your_textarea').val(),
    // look for any "\n" occurences
    matches = text.match(/\n/g),
    breaks = matches ? matches.length : 2;

jQuery('#your_textarea').attr('rows',breaks + 2);

HTML image bottom alignment inside DIV container

Flexboxes can accomplish this by using align-items: flex-end; with display: flex; or display: inline-flex;

div#imageContainer {
    height: 160px;  
    align-items: flex-end;
    display: flex;

    /* This is the default value, so you only need to explicitly set it if it's already being set to something else elsewhere. */
    /*flex-direction: row;*/
}

JSFiddle example

CSS-Tricks has a good guide for flexboxes

How to calculate a logistic sigmoid function in Python?

import numpy as np

def sigmoid(x):
    s = 1 / (1 + np.exp(-x))
    return s

result = sigmoid(0.467)
print(result)

The above code is the logistic sigmoid function in python. If I know that x = 0.467 , The sigmoid function, F(x) = 0.385. You can try to substitute any value of x you know in the above code, and you will get a different value of F(x).

Excel function to get first word from sentence in other cell

A1                   A2 
Toronto<b> is nice   =LEFT(A1,(FIND("<",A1,1)-1))

Not sure if the syntax is correct but the forumla in A2 will work for you,

Python string class like StringBuilder in C#?

There is no explicit analogue - i think you are expected to use string concatenations(likely optimized as said before) or third-party class(i doubt that they are a lot more efficient - lists in python are dynamic-typed so no fast-working char[] for buffer as i assume). Stringbuilder-like classes are not premature optimization because of innate feature of strings in many languages(immutability) - that allows many optimizations(for example, referencing same buffer for slices/substrings). Stringbuilder/stringbuffer/stringstream-like classes work a lot faster than concatenating strings(producing many small temporary objects that still need allocations and garbage collection) and even string formatting printf-like tools, not needing of interpreting formatting pattern overhead that is pretty consuming for a lot of format calls.

Escaping single quotes in JavaScript string for JavaScript evaluation

Best to use JSON.stringify() to cover all your bases, like backslashes and other special characters. Here's your original function with that in place instead of modifying strInputString:

function testEscape() {
    var strResult = "";
    var strInputString = "fsdsd'4565sd";

    var strTest = "strResult = " + JSON.stringify(strInputString) + ";";
    eval(strTest);
    alert(strResult);
}

(This way your strInputString could be something like \\\'\"'"''\\abc'\ and it will still work fine.)

Note that it adds its own surrounding double-quotes, so you don't need to include single quotes anymore.

How to select an option from drop down using Selenium WebDriver C#?

This is how it works for me (selecting control by ID and option by text):

protected void clickOptionInList(string listControlId, string optionText)
{
     driver.FindElement(By.XPath("//select[@id='"+ listControlId + "']/option[contains(.,'"+ optionText +"')]")).Click();
}

use:

clickOptionInList("ctl00_ContentPlaceHolder_lbxAllRoles", "Tester");

Creating an array from a text file in Bash

This answer says to use

mapfile -t myArray < file.txt

I made a shim for mapfile if you want to use mapfile on bash < 4.x for whatever reason. It uses the existing mapfile command if you are on bash >= 4.x

Currently, only options -d and -t work. But that should be enough for that command above. I've only tested on macOS. On macOS Sierra 10.12.6, the system bash is 3.2.57(1)-release. So the shim can come in handy. You can also just update your bash with homebrew, build bash yourself, etc.

It uses this technique to set variables up one call stack.

Difference between 'struct' and 'typedef struct' in C++?

In this DDJ article, Dan Saks explains one small area where bugs can creep through if you do not typedef your structs (and classes!):

If you want, you can imagine that C++ generates a typedef for every tag name, such as

typedef class string string;

Unfortunately, this is not entirely accurate. I wish it were that simple, but it's not. C++ can't generate such typedefs for structs, unions, or enums without introducing incompatibilities with C.

For example, suppose a C program declares both a function and a struct named status:

int status(); struct status;

Again, this may be bad practice, but it is C. In this program, status (by itself) refers to the function; struct status refers to the type.

If C++ did automatically generate typedefs for tags, then when you compiled this program as C++, the compiler would generate:

typedef struct status status;

Unfortunately, this type name would conflict with the function name, and the program would not compile. That's why C++ can't simply generate a typedef for each tag.

In C++, tags act just like typedef names, except that a program can declare an object, function, or enumerator with the same name and the same scope as a tag. In that case, the object, function, or enumerator name hides the tag name. The program can refer to the tag name only by using the keyword class, struct, union, or enum (as appropriate) in front of the tag name. A type name consisting of one of these keywords followed by a tag is an elaborated-type-specifier. For instance, struct status and enum month are elaborated-type-specifiers.

Thus, a C program that contains both:

int status(); struct status;

behaves the same when compiled as C++. The name status alone refers to the function. The program can refer to the type only by using the elaborated-type-specifier struct status.

So how does this allow bugs to creep into programs? Consider the program in Listing 1. This program defines a class foo with a default constructor, and a conversion operator that converts a foo object to char const *. The expression

p = foo();

in main should construct a foo object and apply the conversion operator. The subsequent output statement

cout << p << '\n';

should display class foo, but it doesn't. It displays function foo.

This surprising result occurs because the program includes header lib.h shown in Listing 2. This header defines a function also named foo. The function name foo hides the class name foo, so the reference to foo in main refers to the function, not the class. main can refer to the class only by using an elaborated-type-specifier, as in

p = class foo();

The way to avoid such confusion throughout the program is to add the following typedef for the class name foo:

typedef class foo foo;

immediately before or after the class definition. This typedef causes a conflict between the type name foo and the function name foo (from the library) that will trigger a compile-time error.

I know of no one who actually writes these typedefs as a matter of course. It requires a lot of discipline. Since the incidence of errors such as the one in Listing 1 is probably pretty small, you many never run afoul of this problem. But if an error in your software might cause bodily injury, then you should write the typedefs no matter how unlikely the error.

I can't imagine why anyone would ever want to hide a class name with a function or object name in the same scope as the class. The hiding rules in C were a mistake, and they should not have been extended to classes in C++. Indeed, you can correct the mistake, but it requires extra programming discipline and effort that should not be necessary.

Can PHP cURL retrieve response headers AND body in a single request?

Just set options :

  • CURLOPT_HEADER, 0

  • CURLOPT_RETURNTRANSFER, 1

and use curl_getinfo with CURLINFO_HTTP_CODE (or no opt param and you will have an associative array with all the informations you want)

More at : http://php.net/manual/fr/function.curl-getinfo.php

Reset textbox value in javascript

First, select the element. You can usually use the ID like this:

$("#searchField"); // select element by using "#someid"

Then, to set the value, use .val("something") as in:

$("#searchField").val("something"); // set the value

Note that you should only run this code when the element is available. The usual way to do this is:

$(document).ready(function() { // execute when everything is loaded
    $("#searchField").val("something"); // set the value
});

How do I make a Mac Terminal pop-up/alert? Applescript?

And my 15 cent. A one liner for the mac terminal etc just set the MIN= to whatever and a message

MIN=15 && for i in $(seq $(($MIN*60)) -1 1); do echo "$i, "; sleep 1; done; echo -e "\n\nMac Finder should show a popup" afplay /System/Library/Sounds/Funk.aiff; osascript -e 'tell app "Finder" to display dialog "Look away. Rest your eyes"'

A bonus example for inspiration to combine more commands; this will put a mac put to standby sleep upon the message too :) the sudo login is needed then, a multiplication as the 60*2 for two hours goes aswell

sudo su
clear; echo "\n\nPreparing for a sleep when timers done \n"; MIN=60*2 && for i in $(seq $(($MIN*60)) -1 1); do printf "\r%02d:%02d:%02d" $((i/3600)) $(( (i/60)%60)) $((i%60)); sleep 1; done; echo "\n\n Time to sleep  zzZZ";  afplay /System/Library/Sounds/Funk.aiff; osascript -e 'tell app "Finder" to display dialog "Time to sleep zzZZ"'; shutdown -h +1 -s

What is the syntax for Typescript arrow functions with generics?

This works for me

const Generic = <T> (value: T) => {
    return value;
} 

How to find largest objects in a SQL Server database?

You may also use the following code:

USE AdventureWork
GO
CREATE TABLE #GetLargest 
(
  table_name    sysname ,
  row_count     INT,
  reserved_size VARCHAR(50),
  data_size     VARCHAR(50),
  index_size    VARCHAR(50),
  unused_size   VARCHAR(50)
)

SET NOCOUNT ON

INSERT #GetLargest

EXEC sp_msforeachtable 'sp_spaceused ''?'''

SELECT 
  a.table_name,
  a.row_count,
  COUNT(*) AS col_count,
  a.data_size
  FROM #GetLargest a
     INNER JOIN information_schema.columns b
     ON a.table_name collate database_default
     = b.table_name collate database_default
       GROUP BY a.table_name, a.row_count, a.data_size
       ORDER BY CAST(REPLACE(a.data_size, ' KB', '') AS integer) DESC

DROP TABLE #GetLargest

Check mySQL version on Mac 10.8.5

Every time you used the mysql console, the version is shown.

 mysql -u user

Successful console login shows the following which includes the mysql server version.

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1432
Server version: 5.5.9-log Source distribution

Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

You can also check the mysql server version directly by executing the following command:

mysql --version

You may also check the version information from the mysql console itself using the version variables:

mysql> SHOW VARIABLES LIKE "%version%";

Output will be something like this:

+-------------------------+---------------------+
| Variable_name           | Value               |
+-------------------------+---------------------+
| innodb_version          | 1.1.5               |
| protocol_version        | 10                  |
| slave_type_conversions  |                     |
| version                 | 5.5.9-log           |
| version_comment         | Source distribution |
| version_compile_machine | i386                |
| version_compile_os      | osx10.4             |
+-------------------------+---------------------+
7 rows in set (0.01 sec)

You may also use this:

mysql> select @@version;

The STATUS command display version information as well.

mysql> STATUS

You can also check the version by executing this command:

mysql -v

It's worth mentioning that if you have encountered something like this:

ERROR 2002 (HY000): Can't connect to local MySQL server through socket
'/tmp/mysql.sock' (2)

you can fix it by:

sudo ln -s /Applications/MAMP/tmp/mysql/mysql.sock /tmp/mysql.sock

When to use Comparable and Comparator

Use Comparable if you want to define a default (natural) ordering behaviour of the object in question, a common practice is to use a technical or natural (database?) identifier of the object for this.

Use Comparator if you want to define an external controllable ordering behaviour, this can override the default ordering behaviour.

Swift Set to Array

I created a simple extension that gives you an unsorted Array as a property of Set in Swift 4.0.

extension Set {
    var array: [Element] {
        return Array(self)
    }
}

If you want a sorted array, you can either add an additional computed property, or modify the existing one to suit your needs.

To use this, just call

let array = set.array

Clear all fields in a form upon going back with browser back button

This is what worked for me.

$(window).bind("pageshow", function() {
    $("#id").val('');
    $("#another_id").val('');
});

I initially had this in the $(document).ready section of my jquery, which also worked. However, I heard that not all browsers fire $(document).ready on hitting back button, so I took it out. I don't know the pros and cons of this approach, but I have tested on multiple browsers and on multiple devices, and no issues with this solution were found.

Prefer composition over inheritance?

With all the undeniable benefits provided by inheritance, here's some of its disadvantages.

Disadvantages of Inheritance:

  1. You can't change the implementation inherited from super classes at runtime (obviously because inheritance is defined at compile time).
  2. Inheritance exposes a subclass to details of its parent class implementation, that's why it's often said that inheritance breaks encapsulation (in a sense that you really need to focus on interfaces only not implementation, so reusing by sub classing is not always preferred).
  3. The tight coupling provided by inheritance makes the implementation of a subclass very bound up with the implementation of a super class that any change in the parent implementation will force the sub class to change.
  4. Excessive reusing by sub-classing can make the inheritance stack very deep and very confusing too.

On the other hand Object composition is defined at runtime through objects acquiring references to other objects. In such a case these objects will never be able to reach each-other's protected data (no encapsulation break) and will be forced to respect each other's interface. And in this case also, implementation dependencies will be a lot less than in case of inheritance.

Module AppRegistry is not registered callable module (calling runApplication)

One of the libraries has not been linked. To check, just comment out in the package.json one by one the latest libraries added.

yarn remove libraryName.

Then run the app with xcode and puf !

How to call a method function from another class?

In class WeatherRecord:

First import the class if they are in different package else this statement is not requires

Import <path>.ClassName



Then, just referene or call your object like:

Date d;
TempratureRange tr;
d = new Date();
tr = new TempratureRange;
//this can be done in Single Line also like :
// Date d = new Date();



But in your code you are not required to create an object to call function of Date and TempratureRange. As both of the Classes contain Static Function , you cannot call the thoes function by creating object.

Date.date(date,month,year);   // this is enough to call those static function 


Have clear concept on Object and Static functions. Click me

$.focus() not working

In my case, and in case someone else runs into this, I load a form for view, user clicks "Edit" and ajax gets & returns values and updates the form.

Just after this, I tried all of these and none worked except:

setTimeout(function() { $('input[name="q"]').focus() }, 3000);

which I had to change to (due to ajax):

setTimeout(function() { $('input[name="q"]').focus() }, **500**);

and I finally just used $("#q") even though it was an input:

setTimeout(function () { $("#q").focus() }, 500);

How to pass parameter to function using in addEventListener?

In the first line of your JS code:

select.addEventListener('change', getSelection(this), false);

you're invoking getSelection by placing (this) behind the function reference. That is most likely not what you want, because you're now passing the return value of that call to addEventListener, instead of a reference to the actual function itself.


In a function invoked by addEventListener the value for this will automatically be set to the object the listener is attached to, productLineSelect in this case.

If that is what you want, you can just pass the function reference and this will in this example be select in invocations from addEventListener:

select.addEventListener('change', getSelection, false);

If that is not what you want, you'd best bind your value for this to the function you're passing to addEventListener:

var thisArg = { custom: 'object' };
select.addEventListener('change', getSelection.bind(thisArg), false);

The .bind part is also a call, but this call just returns the same function we're calling bind on, with the value for this inside that function scope fixed to thisArg, effectively overriding the dynamic nature of this-binding.


To get to your actual question: "How to pass parameters to function in addEventListener?"

You would have to use an additional function definition:

var globalVar = 'global';

productLineSelect.addEventListener('change', function(event) {
    var localVar = 'local';
    getSelection(event, this, globalVar, localVar);
}, false);

Now we pass the event object, a reference to the value of this inside the callback of addEventListener, a variable defined and initialised inside that callback, and a variable from outside the entire addEventListener call to your own getSelection function.


We also might again have an object of our choice to be this inside the outer callback:

var thisArg = { custom: 'object' };
var globalVar = 'global';

productLineSelect.addEventListener('change', function(event) {
    var localVar = 'local';
    getSelection(event, this, globalVar, localVar);
}.bind(thisArg), false);

How to set $_GET variable

I know this is an old thread, but I wanted to post my 2 cents...

Using Javascript you can achieve this without using $_POST, and thus avoid reloading the page..

<script>
function ButtonPressed()
{
window.location='index.php?view=next'; //this will set $_GET['view']='next'
}
</script>

<button type='button' onClick='ButtonPressed()'>Click me!</button>

<?PHP
 if(isset($_GET['next']))
    {
          echo "This will display after pressing the 'Click Me' button!";
    }
 ?>

How can I add the new "Floating Action Button" between two widgets/layouts

You can import the sample project of Google in Android Studio by clicking File > Import Sample...

Import sample

This Sample contains a FloatingActionButton View which inherits from FrameLayout.

Edit With the new Support Design Library you can implement it like in this example: https://github.com/chrisbanes/cheesesquare

How do I show a running clock in Excel?

See the below code (taken from this post)

Put this code in a Module in VBA (Developer Tab -> Visual Basic)

Dim TimerActive As Boolean
Sub StartTimer()
    Start_Timer
End Sub
Private Sub Start_Timer()
    TimerActive = True
    Application.OnTime Now() + TimeValue("00:01:00"), "Timer"
End Sub
Private Sub Stop_Timer()
    TimerActive = False
End Sub
Private Sub Timer()
    If TimerActive Then
        ActiveSheet.Cells(1, 1).Value = Time
        Application.OnTime Now() + TimeValue("00:01:00"), "Timer"
    End If
End Sub

You can invoke the "StartTimer" function when the workbook opens and have it repeat every minute by adding the below code to your workbooks Visual Basic "This.Workbook" class in the Visual Basic editor.

Private Sub Workbook_Open()
    Module1.StartTimer
End Sub

Now, every time 1 minute passes the Timer procedure will be invoked, and set cell A1 equal to the current time.

How to Verify if file exist with VB script

There is no built-in functionality in VBS for that, however, you can use the FileSystemObject FileExists function for that :

Option Explicit
DIM fso    
Set fso = CreateObject("Scripting.FileSystemObject")

If (fso.FileExists("C:\Program Files\conf")) Then
  WScript.Echo("File exists!")
  WScript.Quit()
Else
  WScript.Echo("File does not exist!")
End If

WScript.Quit()

T-SQL substring - separating first and last name

Assuming the FirstName is all of the characters up to the first space:

SELECT
  SUBSTRING(username, 1, CHARINDEX(' ', username) - 1) AS FirstName,
  SUBSTRING(username, CHARINDEX(' ', username) + 1, LEN(username)) AS LastName
FROM
  whereever

In Angular, What is 'pathmatch: full' and what effect does it have?

pathMatch = 'full' results in a route hit when the remaining, unmatched segments of the URL match is the prefix path

pathMatch = 'prefix' tells the router to match the redirect route when the remaining URL begins with the redirect route's prefix path.

Ref: https://angular.io/guide/router#set-up-redirects

pathMatch: 'full' means, that the whole URL path needs to match and is consumed by the route matching algorithm.

pathMatch: 'prefix' means, the first route where the path matches the start of the URL is chosen, but then the route matching algorithm is continuing searching for matching child routes where the rest of the URL matches.

how to convert milliseconds to date format in android?

public class LogicconvertmillistotimeActivity extends Activity {
    /** Called when the activity is first created. */
     EditText millisedit;
        Button   millisbutton;
        TextView  millistextview;
        long millislong;
        String millisstring;
        int millisec=0,sec=0,min=0,hour=0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        millisedit=(EditText)findViewById(R.id.editText1);
        millisbutton=(Button)findViewById(R.id.button1);
        millistextview=(TextView)findViewById(R.id.textView1);
        millisbutton.setOnClickListener(new View.OnClickListener() {            
            @Override
            public void onClick(View v) {   
                millisbutton.setClickable(false);
                millisec=0;
                sec=0;
                min=0;
                hour=0;
                millisstring=millisedit.getText().toString().trim();
                millislong= Long.parseLong(millisstring);
                Calendar cal = Calendar.getInstance();
                SimpleDateFormat formatter = new SimpleDateFormat("HH:mm:ss");
                if(millislong>1000){
                    sec=(int) (millislong/1000);
                    millisec=(int)millislong%1000;
                    if(sec>=60){
                        min=sec/60;
                        sec=sec%60;
                    }
                    if(min>=60){
                        hour=min/60;
                        min=min%60;
                    }
                }
                else
                {
                    millisec=(int)millislong;
                }
                cal.clear();
                cal.set(Calendar.HOUR_OF_DAY,hour);
                cal.set(Calendar.MINUTE,min);
                cal.set(Calendar.SECOND, sec);
                cal.set(Calendar.MILLISECOND,millisec);
                String DateFormat = formatter.format(cal.getTime());
//              DateFormat = "";
                millistextview.setText(DateFormat);

            }
        });
    }
}

How to drop all tables from the database with manage.py CLI in Django?

There's an even simpler answer if you want to delete ALL your tables. You just go to your folder containing the database (which may be called mydatabase.db) and right-click the .db file and push "delete." Old fashioned way, sure-fire to work.

Python: count repeated elements in the list

lst = ["a", "b", "a", "c", "c", "a", "c"]
temp=set(lst)
result={}
for i in temp:
    result[i]=lst.count(i)
print result

Output:

{'a': 3, 'c': 3, 'b': 1}

How can I fill a column with random numbers in SQL? I get the same value in every row

While I do love using CHECKSUM, I feel that a better way to go is using NEWID(), just because you don't have to go through a complicated math to generate simple numbers .

ROUND( 1000 *RAND(convert(varbinary, newid())), 0)

You can replace the 1000 with whichever number you want to set as the limit, and you can always use a plus sign to create a range, let's say you want a random number between 100 and 200, you can do something like :

100 + ROUND( 100 *RAND(convert(varbinary, newid())), 0)

Putting it together in your query :

UPDATE CattleProds 
SET SheepTherapy= ROUND( 1000 *RAND(convert(varbinary, newid())), 0)
WHERE SheepTherapy IS NULL

gradlew: Permission Denied

I got the same error trying to execute flutter run on a mac. Apparently, in your flutter project, there is a file android/gradlew that is expected to be executable (and it wasn't). So in my case,

chmod a+rx android/gradlew

i used this command and execute the project

How to navigate a few folders up?

C#

string upTwoDir = Path.GetFullPath(Path.Combine(System.AppContext.BaseDirectory, @"..\..\"));

How do I reformat HTML code using Sublime Text 2?

I recommend this plugin: HTML/CSS/JS Prettify, It really works.

After the installation, just select the code and press Ctrl+Shift+H.

Done!

Ball to Ball Collision - Detection and Handling

One thing I see here to optimize.

While I do agree that the balls hit when the distance is the sum of their radii one should never actually calculate this distance! Rather, calculate it's square and work with it that way. There's no reason for that expensive square root operation.

Also, once you have found a collision you have to continue to evaluate collisions until no more remain. The problem is that the first one might cause others that have to be resolved before you get an accurate picture. Consider what happens if the ball hits a ball at the edge? The second ball hits the edge and immediately rebounds into the first ball. If you bang into a pile of balls in the corner you could have quite a few collisions that have to be resolved before you can iterate the next cycle.

As for the O(n^2), all you can do is minimize the cost of rejecting ones that miss:

1) A ball that is not moving can't hit anything. If there are a reasonable number of balls lying around on the floor this could save a lot of tests. (Note that you must still check if something hit the stationary ball.)

2) Something that might be worth doing: Divide the screen into a number of zones but the lines should be fuzzy--balls at the edge of a zone are listed as being in all the relevant (could be 4) zones. I would use a 4x4 grid, store the zones as bits. If an AND of the zones of two balls zones returns zero, end of test.

3) As I mentioned, don't do the square root.

How do you change library location in R?

I've used this successfully inside R script:

library("reshape2",lib.loc="/path/to/R-packages/")

useful if for whatever reason libraries are in more than one place.

CSS: Force float to do a whole new line

I fixed it by removing float:left, and adding display:inline-block instead. Haven't used it for images, but should work fine, there, too.

How to make bootstrap 3 fluid layout without horizontal scrollbar

Found this workaround

.row {
  margin-left: 0;
  margin-right: 0;
}
[class^="col-"] > [class^="col-"]:first-child,
[class^="col-"] > [class*=" col-"]:first-child
[class*=" col-"] > [class^="col-"]:first-child,
[class*=" col-"]> [class*=" col-"]:first-child,
.row > [class^="col-"]:first-child,
.row > [class*=" col-"]:first-child{
  padding-left: 0px;
}
[class^="col-"] > [class^="col-"]:last-child,
[class^="col-"] > [class*=" col-"]:last-child
[class*=" col-"] > [class^="col-"]:last-child,
[class*=" col-"]> [class*=" col-"]:last-child,
.row > [class^="col-"]:last-child,
.row > [class*=" col-"]:last-child{
    padding-right: 0px;
}

How to do paging in AngularJS?

Since Angular 1.4, the limitTo filter also accepts a second optional argument begin

From the docs:

{{ limitTo_expression | limitTo : limit : begin}}

begin (optional) string|number
Index at which to begin limitation. As a negative index, begin indicates an offset from the end of input. Defaults to 0.

So you don't need to create a new directive, This argument can be used to set the offset of the pagination

ng-repeat="item in vm.items| limitTo: vm.itemsPerPage: (vm.currentPage-1)*vm.itemsPerPage" 

What exactly does += do in python?

In Python, += is sugar coating for the __iadd__ special method, or __add__ or __radd__ if __iadd__ isn't present. The __iadd__ method of a class can do anything it wants. The list object implements it and uses it to iterate over an iterable object appending each element to itself in the same way that the list's extend method does.

Here's a simple custom class that implements the __iadd__ special method. You initialize the object with an int, then can use the += operator to add a number. I've added a print statement in __iadd__ to show that it gets called. Also, __iadd__ is expected to return an object, so I returned the addition of itself plus the other number which makes sense in this case.

>>> class Adder(object):
        def __init__(self, num=0):
            self.num = num

        def __iadd__(self, other):
            print 'in __iadd__', other
            self.num = self.num + other
            return self.num

>>> a = Adder(2)
>>> a += 3
in __iadd__ 3
>>> a
5

Hope this helps.

ReCaptcha API v2 Styling

You can use some CSS for Google reCAPTCHA v2 styling on your website:

– Change background, color of Google reCAPTCHA v2 widget:

.rc-anchor-light { 
background: #fff!important; 
color: #fff!important; }

or

.rc-anchor-normal{
background: #000 !important; 
color: #000 !important; }

– Resize the Google reCAPTCHA v2 widget by using this snippet:

.rc-anchor-light { 
transform:scale(0.9); 
-webkit-transform:scale(0.9); }

– Responsive your Google reCAPTCHA v2:

@media only screen and (min-width: 768px) {
.rc-anchor-light { 
transform:scale(0.85); 
-webkit-transform:scale(0.85); } 
}

All elements, property of CSS above that’s just for your reference. You can change them by yourself (only using CSS class selector).

Refer on OIW Blog - How To Edit CSS of Google reCAPTCHA (Re-style, Change Position, Resize reCAPTCHA Badge)

You can also find out Google reCAPTCHA v3's styling there.

Declare and assign multiple string variables at the same time

An example of what I call Concatenated-declarations:

string Camnr = "",
        Klantnr = "",
        Ordernr = "",
        Bonnr = "",
        Volgnr = "",
        Omschrijving = "",
        Startdatum = "",
        Bonprioriteit = "",
        Matsoort = "",
        Dikte = "",
        Draaibaarheid = "",
        Draaiomschrijving = "",
        Orderleverdatum = "",
        Regeltaakkode = "",
        Gebruiksvoorkeur = "",
        Regelcamprog = "",
        Regeltijd = "",
        Orderrelease = "";

Just my 2 cents, hope it helps someone somewhere.

Add/remove class with jquery based on vertical scroll?

Add some transition effect to it if you like:

http://jsbin.com/boreme/17/edit?html,css,js

.clearHeader {
  height:50px;
  background:lightblue;
  position:fixed;
  top:0;
  left:0;
  width:100%;

  -webkit-transition: background 2s; /* For Safari 3.1 to 6.0 */
  transition: background 2s;
}

.clearHeader.darkHeader {
 background:#000;
}

How to get Locale from its String representation in Java?

Option 1 :

org.apache.commons.lang3.LocaleUtils.toLocale("en_US")

Option 2 :

Locale.forLanguageTag("en-US")

Please note Option 1 is "underscore" between language and country , and Option 2 is "dash".

What is the usefulness of PUT and DELETE HTTP request methods?

Using HTTP Request verb such as GET, POST, DELETE, PUT etc... enables you to build RESTful web applications. Read about it here: http://en.wikipedia.org/wiki/Representational_state_transfer

The easiest way to see benefits from this is to look at this example. Every MVC framework has a Router/Dispatcher that maps URL-s to actionControllers. So URL like this: /blog/article/1 would invoke blogController::articleAction($id); Now this Router is only aware of the URL or /blog/article/1/

But if that Router would be aware of whole HTTP Request object instead of just URL, he could have access HTTP Request verb (GET, POST, PUT, DELETE...), and many other useful stuff about current HTTP Request.

That would enable you to configure application so it can accept the same URL and map it to different actionControllers depending on the HTTP Request verb.

For example:

if you want to retrive article 1 you can do this:

GET /blog/article/1 HTTP/1.1

but if you want to delete article 1 you will do this:

DELETE /blog/article/1 HTTP/1.1

Notice that both HTTP Requests have the same URI, /blog/article/1, the only difference is the HTTP Request verb. And based on that verb your router can call different actionController. This enables you to build neat URL-s.

Read this two articles, they might help you:

Symfony 2 - HTTP Fundamentals

Symfony 2 - Routing

These articles are about Symfony 2 framework, but they can help you to figure out how does HTTP Requests and Responses work.

Hope this helps!

Subset dataframe by multiple logical conditions of rows to remove

my.df <- read.table(textConnection("
v1 v2 v3 v4
a  v  d  c
a  v  d  d
b  n  p  g
b  d  d  h    
c  k  d  c    
c  r  p  g
d  v  d  x
d  v  d  c
e  v  d  b
e  v  d  c"), header = TRUE)

my.df[which(my.df$v1 != "b" & my.df$v1 != "d" & my.df$v1 != "e" ), ]

  v1 v2 v3 v4
1  a  v  d  c
2  a  v  d  d
5  c  k  d  c
6  c  r  p  g

Missing .map resource?

jQuery recently started using source maps.

For example, let's look at the minified jQuery 2.0.3 file's first few lines.

/*! jQuery v2.0.3 | (c) 2005, 2013 jQuery Foundation, Inc. | jquery.org/license
//@ sourceMappingURL=jquery.min.map
*/

Excerpt from Introduction to JavaScript Source Maps:

Have you ever found yourself wishing you could keep your client-side code readable and more importantly debuggable even after you've combined and minified it, without impacting performance? Well now you can through the magic of source maps.

Basically it's a way to map a combined/minified file back to an unbuilt state. When you build for production, along with minifying and combining your JavaScript files, you generate a source map which holds information about your original files. When you query a certain line and column number in your generated JavaScript you can do a lookup in the source map which returns the original location. Developer tools (currently WebKit nightly builds, Google Chrome, or Firefox 23+) can parse the source map automatically and make it appear as though you're running unminified and uncombined files.

emphasis mine

It's incredibly useful, and will only download if the user opens dev tools.

Solution

Remove the source mapping line, or do nothing. It isn't really a problem.


Side note: your server should return 404, not 500. It could point to a security problem if this happens in production.

How can I format the output of a bash command in neat columns

If your output is delimited by tabs a quick solution would be to use the tabs command to adjust the size of your tabs.

tabs 20
keys | awk '{ print $1"\t\t" $2 }'

LINQ query to find if items in a list are contained in another list

I think this would be easiest one:

test1.ForEach(str => test2.RemoveAll(x=>x.Contains(str)));

Drawing circles with System.Drawing

There is no DrawCircle method; use DrawEllipse instead. I have a static class with handy graphics extension methods. The following ones draw and fill circles. They are wrappers around DrawEllipse and FillEllipse:

public static class GraphicsExtensions
{
    public static void DrawCircle(this Graphics g, Pen pen,
                                  float centerX, float centerY, float radius)
    {
        g.DrawEllipse(pen, centerX - radius, centerY - radius,
                      radius + radius, radius + radius);
    }

    public static void FillCircle(this Graphics g, Brush brush,
                                  float centerX, float centerY, float radius)
    {
        g.FillEllipse(brush, centerX - radius, centerY - radius,
                      radius + radius, radius + radius);
    }
}

You can call them like this:

g.FillCircle(myBrush, centerX, centerY, radius);
g.DrawCircle(myPen, centerX, centerY, radius);

Unsigned values in C

Assign a int -1 to an unsigned: As -1 does not fit in the range [0...UINT_MAX], multiples of UINT_MAX+1 are added until the answer is in range. Evidently UINT_MAX is pow(2,32)-1 or 429496725 on OP's machine so a has the value of 4294967295.

    unsigned int a = -1;

The "%x", "%u" specifier expects a matching unsigned. Since these do not match, "If a conversion specification is invalid, the behavior is undefined. If any argument is not the correct type for the corresponding conversion specification, the behavior is undefined." C11 §7.21.6.1 9. The printf specifier does not change b.

    printf("%x\n", b);  // UB
    printf("%u\n", b);  // UB

The "%d" specifier expects a matching int. Since these do not match, more UB.

    printf("%d\n", a);  // UB

Given undefined behavior, the conclusions are not supported.


both cases, the bytes are the same (ffffffff).

Even with the same bit pattern, different types may have different values. ffffffff as an unsigned has the value of 4294967295. As an int, depending signed integer encoding, it has the value of -1, -2147483647 or TBD. As a float it may be a NAN.

what is unsigned word for?

unsigned stores a whole number in the range [0 ... UINT_MAX]. It never has a negative value. If code needs a non-negative number, use unsigned. If code needs a counting number that may be +, - or 0, use int.


Update: to avoid a compiler warning about assigning a signed int to unsigned, use the below. This is an unsigned 1u being negated - which is well defined as above. The effect is the same as a -1, but conveys to the compiler direct intentions.

unsigned int a = -1u;

Android Studio - Gradle sync project failed

I had a "Install build tools and sync" link in the lower right hand corner of my screen. I clicked on that and it fixed the issue.

jQuery: set selected value of dropdown list?

You need to select jQuery in the dropdown on the left and you have a syntax error because the $(document).ready should end with }); not )}; Check this link.

Swift Error: Editor placeholder in source file

Clean Build folder + Build

will clear any error you may have even after fixing your code.

NSCameraUsageDescription in iOS 10.0 runtime crash?

the xcode UI has changed a bit from one version to the next so here is where you update the plist for 9.0 beta 4 if it helps Project ->Target ->Infoenter image description here

how to select rows based on distinct values of A COLUMN only

Try this - you need a CTE (Common Table Expression) that partitions (groups) your data by distinct e-mail address, and sorts each group by ID - smallest first. Then you just select the first entry for each group - that should give you what you're looking for:

;WITH DistinctMails AS
(
    SELECT ID, MailID, EMailAddress, NAME,
        ROW_NUMBER() OVER(PARTITION BY EMailAddress ORDER BY ID) AS 'RowNum'
    FROM dbo.YourMailTable
)
SELECT *
FROM DistinctMails
WHERE RowNum = 1

This works on SQL Server 2005 and newer (you didn't mention what version you're using...)

Custom CSS Scrollbar for Firefox

It works in user-style, and it seems not to work in web pages. I have not found official direction from Mozilla on this. While it may have worked at some point, Firefox does not have official support for this. This bug is still open https://bugzilla.mozilla.org/show_bug.cgi?id=77790

scrollbar {
/*  clear useragent default style*/
   -moz-appearance: none !important;
}
/* buttons at two ends */
scrollbarbutton {
   -moz-appearance: none !important;
}
/* the sliding part*/
thumb{
   -moz-appearance: none !important;
}
scrollcorner {
   -moz-appearance: none !important;
   resize:both;
}
/* vertical or horizontal */
scrollbar[orient="vertical"] {
    color:silver;
}

check http://codemug.com/html/custom-scrollbars-using-css/ for details.

Class file for com.google.android.gms.internal.zzaja not found

I have a also same problem.Change old version of FirebaseAuth to newer version. for me I change "com.google.firebase:firebase-auth:11.4.0" to "com.google.firebase:firebase-auth:11.8.0"

`export const` vs. `export default` in ES6

I had the problem that the browser doesn't use ES6.

I have fix it with:

 <script type="module" src="index.js"></script>

The type module tells the browser to use ES6.

export const bla = [1,2,3];

import {bla} from './example.js';

Then it should work.

html table span entire width?

<table border="1"; width=100%>

works for me.

Are there any naming convention guidelines for REST APIs?

Domain names are not case sensitive but the rest of the URI certainly can be. It's a big mistake to assume URIs are not case sensitive.

Quick unix command to display specific lines in the middle of a file?

sed will need to read the data too to count the lines. The only way a shortcut would be possible would there to be context/order in the file to operate on. For example if there were log lines prepended with a fixed width time/date etc. you could use the look unix utility to binary search through the files for particular dates/times

Protractor : How to wait for page complete after click a button?

In this case, you can used:

Page Object:

    waitForURLContain(urlExpected: string, timeout: number) {
        try {
            const condition = browser.ExpectedConditions;
            browser.wait(condition.urlContains(urlExpected), timeout);
        } catch (e) {
            console.error('URL not contain text.', e);
        };
    }

Page Test:

page.waitForURLContain('abc#/efg', 30000);

Installing jdk8 on ubuntu- "unable to locate package" update doesn't fix

Command Line option - Ubuntu

sudo apt-get install python-software-properties
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update

Then in terminal

sudo apt-get install oracle-java8-installer

When there are multiple Java installations on your System, the Java version to use as default can be chosen. To do this, execute the following command.

sudo update-alternatives --config java
sudo update-alternatives --config javac
sudo update-alternatives --config javaws

Edit - Manual Java Installation

Download oracle jdk

http://www.oracle.com/technetwork/java/javase/downloads/index.html

Extract zip into desired folder

 e.g  /usr/local/  after extract /usr/local/jdk1.8.0_65

Setup

sudo update-alternatives --install  /usr/bin/java java /usr/local/jdk1.8.0_65/bin/java 1
sudo update-alternatives --install  /usr/bin/javac javac /usr/local/jdk1.8.0_65/bin/javac 1
sudo update-alternatives --install  /usr/bin/javaws javaws /usr/local/jdk1.8.0_65/bin/javaws 1

sudo update-alternatives --set  java /usr/local/jdk1.8.0_65/bin/java
sudo update-alternatives --set  javac /usr/local/jdk1.8.0_65/bin/javac
sudo update-alternatives --set  javaws /usr/local/jdk1.8.0_65/bin/javaws

Edit /etc/environment set JAVA_HOME path for external applications like Eclipse and Idea

Javascript/jQuery detect if input is focused

With pure javascript:

this === document.activeElement // where 'this' is a dom object

or with jquery's :focus pseudo selector.

$(this).is(':focus');

arranging div one below the other

If you want the two divs to be displayed one above the other, the simplest answer is to remove the float: left;from the css declaration, as this causes them to collapse to the size of their contents (or the css defined size), and, well float up against each other.

Alternatively, you could simply add clear:both; to the divs, which will force the floated content to clear previous floats.

pass post data with window.location.href

Using window.location.href it's not possible to send a POST request.

What you have to do is to set up a form tag with data fields in it, set the action attribute of the form to the URL and the method attribute to POST, then call the submit method on the form tag.

TypeError: can't use a string pattern on a bytes-like object in re.findall()

You want to convert html (a byte-like object) into a string using .decode, e.g. html = response.read().decode('utf-8').

See Convert bytes to a Python String

Remove all whitespace in a string

If you want to remove leading and ending spaces, use str.strip():

sentence = ' hello  apple'
sentence.strip()
>>> 'hello  apple'

If you want to remove all space characters, use str.replace():

(NB this only removes the “normal” ASCII space character ' ' U+0020 but not any other whitespace)

sentence = ' hello  apple'
sentence.replace(" ", "")
>>> 'helloapple'

If you want to remove duplicated spaces, use str.split():

sentence = ' hello  apple'
" ".join(sentence.split())
>>> 'hello apple'

What is the HTML unicode character for a "tall" right chevron?

Use '›'

&rsaquo; -> single right angle quote. For single left angle quote, use &lsaquo;

What's the difference between Html.Label, Html.LabelFor and Html.LabelForModel

I think that the usage of @Html.LabelForModel() should be explained in more detail.

The LabelForModel Method returns an HTML label element and the property name of the property that is represented by the model.

You could refer to the following code:

Code in model:

using System.ComponentModel;

[DisplayName("MyModel")]
public class MyModel
{
    [DisplayName("A property")]
    public string Test { get; set; }
}

Code in view:

@Html.LabelForModel()
<div class="form-group">

    @Html.LabelFor(model => model.Test, new { @class = "control-label col-md-2" })

    <div class="col-md-10">
        @Html.EditorFor(model => model.Test)
        @Html.ValidationMessageFor(model => model.Test)
    </div>
</div>

The output screenshot:

enter image description here

Reference to answer on the asp.net forum

Browser/HTML Force download of image from src="data:image/jpeg;base64..."

I guess an img tag is needed as a child of an a tag, the following way:

<a download="YourFileName.jpeg" href="data:image/jpeg;base64,iVBO...CYII=">
    <img src="data:image/jpeg;base64,iVBO...CYII="></img>
</a>

or

<a download="YourFileName.jpeg" href="/path/to/OtherFile.jpg">
    <img src="/path/to/OtherFile.jpg"></img>
</a>

Only using the a tag as explained in #15 didn't worked for me with the latest version of Firefox and Chrome, but putting the same image data in both a.href and img.src tags worked for me.

From JavaScript it could be generated like this:

var data = canvas.toDataURL("image/jpeg");

var img = document.createElement('img');
img.src = data;

var a = document.createElement('a');
a.setAttribute("download", "YourFileName.jpeg");
a.setAttribute("href", data);
a.appendChild(img);

var w = open();
w.document.title = 'Export Image';
w.document.body.innerHTML = 'Left-click on the image to save it.';
w.document.body.appendChild(a);

iOS 7's blurred overlay effect using CSS?

Check this one out http://codepen.io/GianlucaGuarini/pen/Hzrhf Seems like it does the effect without duplication the background image of the element under itself. See texts are blurring also in the example.

Vague.js

var vague = $blurred.find('iframe').Vague({
  intensity:5 //blur intensity
});
vague.blur();

Jenkins Pipeline Wipe Out Workspace

Using the 'WipeWorkspace' extension seems to work as well. It requires the longer form:

checkout([
   $class: 'GitSCM',
   branches: scm.branches,
   extensions: scm.extensions + [[$class: 'WipeWorkspace']],
   userRemoteConfigs: scm.userRemoteConfigs
])

More details here: https://support.cloudbees.com/hc/en-us/articles/226122247-How-to-Customize-Checkout-for-Pipeline-Multibranch-

Available GitSCM extensions here: https://github.com/jenkinsci/git-plugin/tree/master/src/main/java/hudson/plugins/git/extensions/impl

How to maintain aspect ratio using HTML IMG tag

Why don't you use a separate CSS file to maintain the height and the width of the image you want to display? In that way, you can provide the width and height necessarily.

eg:

       image {
       width: 64px;
       height: 64px;
       }

File path for project files?

I was facing a similar issue, I had a file on my project, and wanted to test a class which had to deal with loading files from the FS and process them some way. What I did was:

  • added the file test.txt to my test project
  • on the solution explorer hit alt-enter (file properties)
  • there I set BuildAction to Content and Copy to Output Directory to Copy if newer, I guess Copy always would have done it as well

then on my tests I just had to Path.Combine(Environment.CurrentDirectory, "test.txt") and that's it. Whenever the project is compiled it will copy the file (and all it's parent path, in case it was in, say, a folder) to the bin\Debug (or whatever configuration you are using) folder.

Hopes this helps someone

How to redirect output to a file and stdout

$ program [arguments...] 2>&1 | tee outfile

2>&1 dumps the stderr and stdout streams. tee outfile takes the stream it gets and writes it to the screen and to the file "outfile".

This is probably what most people are looking for. The likely situation is some program or script is working hard for a long time and producing a lot of output. The user wants to check it periodically for progress, but also wants the output written to a file.

The problem (especially when mixing stdout and stderr streams) is that there is reliance on the streams being flushed by the program. If, for example, all the writes to stdout are not flushed, but all the writes to stderr are flushed, then they'll end up out of chronological order in the output file and on the screen.

It's also bad if the program only outputs 1 or 2 lines every few minutes to report progress. In such a case, if the output was not flushed by the program, the user wouldn't even see any output on the screen for hours, because none of it would get pushed through the pipe for hours.

Update: The program unbuffer, part of the expect package, will solve the buffering problem. This will cause stdout and stderr to write to the screen and file immediately and keep them in sync when being combined and redirected to tee. E.g.:

$ unbuffer program [arguments...] 2>&1 | tee outfile

MySQL - length() vs char_length()

LENGTH() returns the length of the string measured in bytes.
CHAR_LENGTH() returns the length of the string measured in characters.

This is especially relevant for Unicode, in which most characters are encoded in two bytes. Or UTF-8, where the number of bytes varies. For example:

select length(_utf8 '€'), char_length(_utf8 '€')
--> 3, 1

As you can see the Euro sign occupies 3 bytes (it's encoded as 0xE282AC in UTF-8) even though it's only one character.

How to convert integer to decimal in SQL Server query?

select cast (height as decimal)/10 as HeightDecimal

Populating Spring @Value during Unit Test

Don't abuse private fields get/set by reflection

Using reflection as that is done in several answers here is something that we could avoid.
It brings a small value here while it presents multiple drawbacks :

  • we detect reflection issues only at runtime (ex: fields not existing any longer)
  • We want encapsulation but not a opaque class that hides dependencies that should be visible and make the class more opaque and less testable.
  • it encourages bad design. Today you declare a @Value String field. Tomorrow you can declare 5 or 10 of them in that class and you may not even be straight aware that you decrease the design of the class. With a more visible approach to set these fields (such as constructor) , you will think twice before adding all these fields and you will probably encapsulate them into another class and use @ConfigurationProperties.

Make your class testable both unitary and in integration

To be able to write both plain unit tests (that is without a running spring container) and integration tests for your Spring component class, you have to make this class usable with or without Spring.
Running a container in an unit test when it is not required is a bad practice that slows down local builds : you don't want that.
I added this answer because no answer here seems to show this distinction and so they rely on a running container systematically.

So I think that you should move this property defined as an internal of the class :

@Component
public class Foo{   
    @Value("${property.value}") private String property;
    //...
}

into a constructor parameter that will be injected by Spring :

@Component
public class Foo{   
    private String property;
     
    public Foo(@Value("${property.value}") String property){
       this.property = property;
    }

    //...         
}

Unit test example

You can instantiate Foo without Spring and inject any value for property thanks to the constructor :

public class FooTest{

   Foo foo = new Foo("dummyValue");

   @Test
   public void doThat(){
      ...
   }
}

Integration test example

You can injecting the property in the context with Spring Boot in this simple way thanks to the properties attribute of @SpringBootTest :

@SpringBootTest(properties="property.value=dummyValue")
public class FooTest{
    
   @Autowired
   Foo foo;
     
   @Test
   public void doThat(){
       ...
   }    
}

You could use as alternative @TestPropertySource but it adds an additional annotation :

@SpringBootTest
@TestPropertySource(properties="property.value=dummyValue")
public class FooTest{ ...}

With Spring (without Spring Boot), it should be a little more complicated but as I didn't use Spring without Spring Boot from a long time I don't prefer say a stupid thing.

As a side note : if you have many @Value fields to set, extracting them into a class annotated with @ConfigurationProperties is more relevant because we don't want a constructor with too many arguments.

Python: AttributeError: '_io.TextIOWrapper' object has no attribute 'split'

You are using str methods on an open file object.

You can read the file as a list of lines by simply calling list() on the file object:

with open('goodlines.txt') as f:
    mylist = list(f)

This does include the newline characters. You can strip those in a list comprehension:

with open('goodlines.txt') as f:
    mylist = [line.rstrip('\n') for line in f]

Cannot truncate table because it is being referenced by a FOREIGN KEY constraint?

You cannot truncate a table if you don't drop the constraints. A disable also doesn't work. you need to Drop everything. i've made a script that drop all constrainsts and then recreate then.

Be sure to wrap it in a transaction ;)

SET NOCOUNT ON
GO

DECLARE @table TABLE(
RowId INT PRIMARY KEY IDENTITY(1, 1),
ForeignKeyConstraintName NVARCHAR(200),
ForeignKeyConstraintTableSchema NVARCHAR(200),
ForeignKeyConstraintTableName NVARCHAR(200),
ForeignKeyConstraintColumnName NVARCHAR(200),
PrimaryKeyConstraintName NVARCHAR(200),
PrimaryKeyConstraintTableSchema NVARCHAR(200),
PrimaryKeyConstraintTableName NVARCHAR(200),
PrimaryKeyConstraintColumnName NVARCHAR(200)
)

INSERT INTO @table(ForeignKeyConstraintName, ForeignKeyConstraintTableSchema, ForeignKeyConstraintTableName, ForeignKeyConstraintColumnName)
SELECT
U.CONSTRAINT_NAME,
U.TABLE_SCHEMA,
U.TABLE_NAME,
U.COLUMN_NAME
FROM
INFORMATION_SCHEMA.KEY_COLUMN_USAGE U
INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS C
ON U.CONSTRAINT_NAME = C.CONSTRAINT_NAME
WHERE
C.CONSTRAINT_TYPE = 'FOREIGN KEY'

UPDATE @table SET
PrimaryKeyConstraintName = UNIQUE_CONSTRAINT_NAME
FROM
@table T
INNER JOIN INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS R
ON T.ForeignKeyConstraintName = R.CONSTRAINT_NAME

UPDATE @table SET
PrimaryKeyConstraintTableSchema = TABLE_SCHEMA,
PrimaryKeyConstraintTableName = TABLE_NAME
FROM @table T
INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS C
ON T.PrimaryKeyConstraintName = C.CONSTRAINT_NAME

UPDATE @table SET
PrimaryKeyConstraintColumnName = COLUMN_NAME
FROM @table T
INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE U
ON T.PrimaryKeyConstraintName = U.CONSTRAINT_NAME

--DROP CONSTRAINT:

DECLARE @dynSQL varchar(MAX);

DECLARE cur CURSOR FOR
SELECT
'
ALTER TABLE [' + ForeignKeyConstraintTableSchema + '].[' + ForeignKeyConstraintTableName + ']
DROP CONSTRAINT ' + ForeignKeyConstraintName + '
'
FROM
@table

OPEN cur

FETCH cur into @dynSQL
WHILE @@FETCH_STATUS = 0 
BEGIN
    exec(@dynSQL)
    print @dynSQL

    FETCH cur into @dynSQL
END
CLOSE cur
DEALLOCATE cur
---------------------



   --HERE GOES YOUR TRUNCATES!!!!!
   --HERE GOES YOUR TRUNCATES!!!!!
   --HERE GOES YOUR TRUNCATES!!!!!

    truncate table your_table

   --HERE GOES YOUR TRUNCATES!!!!!
   --HERE GOES YOUR TRUNCATES!!!!!
   --HERE GOES YOUR TRUNCATES!!!!!

---------------------
--ADD CONSTRAINT:

DECLARE cur2 CURSOR FOR
SELECT
'
ALTER TABLE [' + ForeignKeyConstraintTableSchema + '].[' + ForeignKeyConstraintTableName + ']
ADD CONSTRAINT ' + ForeignKeyConstraintName + ' FOREIGN KEY(' + ForeignKeyConstraintColumnName + ') REFERENCES [' + PrimaryKeyConstraintTableSchema + '].[' + PrimaryKeyConstraintTableName + '](' + PrimaryKeyConstraintColumnName + ')
'
FROM
@table

OPEN cur2

FETCH cur2 into @dynSQL
WHILE @@FETCH_STATUS = 0 
BEGIN
    exec(@dynSQL)

    print @dynSQL

    FETCH cur2 into @dynSQL
END
CLOSE cur2
DEALLOCATE cur2

Hide all warnings in ipython

I eventually figured it out. Place:

import warnings
warnings.filterwarnings('ignore')

inside ~/.ipython/profile_default/startup/disable-warnings.py. I'm leaving this question and answer for the record in case anyone else comes across the same issue.

Quite often it is useful to see a warning once. This can be set by:

warnings.filterwarnings(action='once')

Difference between Width:100% and width:100vw?

vw and vh stand for viewport width and viewport height respectively.

The difference between using width: 100vw instead of width: 100% is that while 100% will make the element fit all the space available, the viewport width has a specific measure, in this case the width of the available screen, including the document margin.

If you set the style body { margin: 0 }, 100vw should behave the same as 100%.

Additional notes

Using vw as unit for everything in your website, including font sizes and heights, will make it so that the site is always displayed proportionally to the device's screen width regardless of it's resolution. This makes it super easy to ensure your website is displayed properly in both workstation and mobile.

You can set font-size: 1vw (or whatever size suits your project) in your body CSS and everything specified in rem units will automatically scale according to the device screen, so it's easy to port existing projects and even frameworks (such as Bootstrap) to this concept.

Can I give a default value to parameters or optional parameters in C# functions?

Yes. See Named and Optional Arguments. Note that the default value needs to be a constant, so this is OK:

public string Foo(string myParam = "default value") // constant, OK
{
}

but this is not:

public void Bar(string myParam = Foo()) // not a constant, not OK
{
}

DateTimePicker: pick both date and time

You can get it to display time. From that you will probably have to have two controls (one date, one time) the accomplish what you want.

SUM OVER PARTITION BY

You could have used DISTINCT or just remove the PARTITION BY portions and use GROUP BY:

SELECT BrandId
       ,SUM(ICount)
       ,TotalICount = SUM(ICount) OVER ()    
       ,Percentage = SUM(ICount) OVER ()*1.0 / SUM(ICount) 
FROM Table 
WHERE DateId  = 20130618
GROUP BY BrandID

Not sure why you are dividing the total by the count per BrandID, if that's a mistake and you want percent of total then reverse those bits above to:

SELECT BrandId
           ,SUM(ICount)
           ,TotalICount = SUM(ICount) OVER ()    
           ,Percentage = SUM(ICount)*1.0 / SUM(ICount) OVER () 
    FROM Table 
    WHERE DateId  = 20130618
    GROUP BY BrandID

Why use prefixes on member variables in C++ classes

You have to be careful with using a leading underscore. A leading underscore before a capital letter in a word is reserved. For example:

_Foo

_L

are all reserved words while

_foo

_l

are not. There are other situations where leading underscores before lowercase letters are not allowed. In my specific case, I found the _L happened to be reserved by Visual C++ 2005 and the clash created some unexpected results.

I am on the fence about how useful it is to mark up local variables.

Here is a link about which identifiers are reserved: What are the rules about using an underscore in a C++ identifier?

MySQL Query GROUP BY day / month / year

The following query worked for me in Oracle Database 12c Release 12.1.0.1.0

SELECT COUNT(*)
FROM stats
GROUP BY 
extract(MONTH FROM TIMESTAMP),
extract(MONTH FROM TIMESTAMP),
extract(YEAR  FROM TIMESTAMP);

sql server Get the FULL month name from a date

If you are using SQL Server 2012 or later, you can use:

SELECT FORMAT(MyDate, 'MMMM dd yyyy')

You can view the documentation for more information on the format.

PHP Sort a multidimensional array by element containing date

For those still looking a solved it this way inside a class with a function sortByDate, see the code below

<?php

class ContactsController 
{
    public function __construct()
    {
    //
    }


    function sortByDate($key)
    {
        return function ($a, $b) use ($key) {
            $t1 = strtotime($a[$key]);
            $t2 = strtotime($b[$key]);
            return $t2-$t1;
        };

    }

    public function index()
    {

        $data[] = array('contact' => '434343434', 'name' => 'dickson','updated_at' =>'2020-06-11 12:38:23','created_at' =>'2020-06-11 12:38:23');
        $data[] = array('contact' => '434343434', 'name' => 'dickson','updated_at' =>'2020-06-16 12:38:23','created_at' =>'2020-06-10 12:38:23');
        $data[] = array('contact' => '434343434', 'name' => 'dickson','updated_at' =>'2020-06-7 12:38:23','created_at' =>'2020-06-9 12:38:23');


        usort($data, $this->sortByDate('updated_at'));

        //usort($data, $this->sortByDate('created_at'));
        echo $data;

    }
}

Is it possible to indent JavaScript code in Notepad++?

JSTool is the best for stability.

Steps:

  1. Select menu Plugins>Plugin Manager>Show Plugin Manager
  2. Check to JSTool checkbox > Install > Restart Notepad++
  3. Open js file > Plugins > JSTool > JSFormat
    screenshot

Reference:

How to find out the MySQL root password

Go to phpMyAdmin > config.inc.php > $cfg['Servers'][$i]['password'] = '';

reading and parsing a TSV file, then manipulating it for saving as CSV (*efficiently*)

You should use the csv module to read the tab-separated value file. Do not read it into memory in one go. Each row you read has all the information you need to write rows to the output CSV file, after all. Keep the output file open throughout.

import csv

with open('sample.txt', newline='') as tsvin, open('new.csv', 'w', newline='') as csvout:
    tsvin = csv.reader(tsvin, delimiter='\t')
    csvout = csv.writer(csvout)

    for row in tsvin:
        count = int(row[4])
        if count > 0:
            csvout.writerows([row[2:4] for _ in range(count)])

or, using the itertools module to do the repeating with itertools.repeat():

from itertools import repeat
import csv

with open('sample.txt', newline='') as tsvin, open('new.csv', 'w', newline='') as csvout:
    tsvin = csv.reader(tsvin, delimiter='\t')
    csvout = csv.writer(csvout)

    for row in tsvin:
        count = int(row[4])
        if count > 0:
            csvout.writerows(repeat(row[2:4], count))

How Should I Set Default Python Version In Windows?

  1. Edit registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\python.exe\default
  2. Set default program to open .py files to python.exe

Passing an array of data as an input parameter to an Oracle procedure

If the types of the parameters are all the same (varchar2 for example), you can have a package like this which will do the following:

CREATE OR REPLACE PACKAGE testuser.test_pkg IS

   TYPE assoc_array_varchar2_t IS TABLE OF VARCHAR2(4000) INDEX BY BINARY_INTEGER;

   PROCEDURE your_proc(p_parm IN assoc_array_varchar2_t);

END test_pkg;

CREATE OR REPLACE PACKAGE BODY testuser.test_pkg IS

   PROCEDURE your_proc(p_parm IN assoc_array_varchar2_t) AS
   BEGIN
      FOR i IN p_parm.first .. p_parm.last
      LOOP
         dbms_output.put_line(p_parm(i));
      END LOOP;

   END;

END test_pkg;

Then, to call it you'd need to set up the array and pass it:

DECLARE
  l_array testuser.test_pkg.assoc_array_varchar2_t;
BEGIN
  l_array(0) := 'hello';
  l_array(1) := 'there';  

  testuser.test_pkg.your_proc(l_array);
END;
/

SQL Query - Using Order By in UNION

Here's an example from Northwind 2007:

SELECT [Product ID], [Order Date], [Company Name], [Transaction], [Quantity]
FROM [Product Orders]
UNION SELECT [Product ID], [Creation Date], [Company Name], [Transaction], [Quantity]
FROM [Product Purchases]
ORDER BY [Order Date] DESC;

The ORDER BY clause just needs to be the last statement, after you've done all your unioning. You can union several sets together, then put an ORDER BY clause after the last set.

What's the most efficient way to check if a record exists in Oracle?

select CASE 
when exists (SELECT U.USERID,U.USERNAME,U.PASSWORDHASH
FROM  TBLUSERS U WHERE U.USERID =U.USERID 
AND U.PASSWORDHASH=U.PASSWORDHASH) 
then 'OLD PASSWORD EXISTS' 
else 'OLD PASSWORD NOT EXISTS' 
end as OUTPUT
from DUAL;

How to set table name in dynamic SQL query?

This is the best way to get a schema dynamically and add it to the different tables within a database in order to get other information dynamically

select @sql = 'insert #tables SELECT ''[''+SCHEMA_NAME(schema_id)+''.''+name+'']'' AS SchemaTable FROM sys.tables'

exec (@sql)

of course #tables is a dynamic table in the stored procedure

Uncaught Error: Unexpected module 'FormsModule' declared by the module 'AppModule'. Please add a @Pipe/@Directive/@Component annotation

Remove the FormsModule from Declaration:[] and Add the FormsModule in imports:[]

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    FormsModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})

Design Patterns web based applications

A bit decent web application consists of a mix of design patterns. I'll mention only the most important ones.


Model View Controller pattern

The core (architectural) design pattern you'd like to use is the Model-View-Controller pattern. The Controller is to be represented by a Servlet which (in)directly creates/uses a specific Model and View based on the request. The Model is to be represented by Javabean classes. This is often further dividable in Business Model which contains the actions (behaviour) and Data Model which contains the data (information). The View is to be represented by JSP files which have direct access to the (Data) Model by EL (Expression Language).

Then, there are variations based on how actions and events are handled. The popular ones are:

  • Request (action) based MVC: this is the simplest to implement. The (Business) Model works directly with HttpServletRequest and HttpServletResponse objects. You have to gather, convert and validate the request parameters (mostly) yourself. The View can be represented by plain vanilla HTML/CSS/JS and it does not maintain state across requests. This is how among others Spring MVC, Struts and Stripes works.

  • Component based MVC: this is harder to implement. But you end up with a simpler model and view wherein all the "raw" Servlet API is abstracted completely away. You shouldn't have the need to gather, convert and validate the request parameters yourself. The Controller does this task and sets the gathered, converted and validated request parameters in the Model. All you need to do is to define action methods which works directly with the model properties. The View is represented by "components" in flavor of JSP taglibs or XML elements which in turn generates HTML/CSS/JS. The state of the View for the subsequent requests is maintained in the session. This is particularly helpful for server-side conversion, validation and value change events. This is how among others JSF, Wicket and Play! works.

As a side note, hobbying around with a homegrown MVC framework is a very nice learning exercise, and I do recommend it as long as you keep it for personal/private purposes. But once you go professional, then it's strongly recommended to pick an existing framework rather than reinventing your own. Learning an existing and well-developed framework takes in long term less time than developing and maintaining a robust framework yourself.

In the below detailed explanation I'll restrict myself to request based MVC since that's easier to implement.


Front Controller pattern (Mediator pattern)

First, the Controller part should implement the Front Controller pattern (which is a specialized kind of Mediator pattern). It should consist of only a single servlet which provides a centralized entry point of all requests. It should create the Model based on information available by the request, such as the pathinfo or servletpath, the method and/or specific parameters. The Business Model is called Action in the below HttpServlet example.

protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    try {
        Action action = ActionFactory.getAction(request);
        String view = action.execute(request, response);

        if (view.equals(request.getPathInfo().substring(1)) {
            request.getRequestDispatcher("/WEB-INF/" + view + ".jsp").forward(request, response);
        }
        else {
            response.sendRedirect(view); // We'd like to fire redirect in case of a view change as result of the action (PRG pattern).
        }
    }
    catch (Exception e) {
        throw new ServletException("Executing action failed.", e);
    }
}

Executing the action should return some identifier to locate the view. Simplest would be to use it as filename of the JSP. Map this servlet on a specific url-pattern in web.xml, e.g. /pages/*, *.do or even just *.html.

In case of prefix-patterns as for example /pages/* you could then invoke URL's like http://example.com/pages/register, http://example.com/pages/login, etc and provide /WEB-INF/register.jsp, /WEB-INF/login.jsp with the appropriate GET and POST actions. The parts register, login, etc are then available by request.getPathInfo() as in above example.

When you're using suffix-patterns like *.do, *.html, etc, then you could then invoke URL's like http://example.com/register.do, http://example.com/login.do, etc and you should change the code examples in this answer (also the ActionFactory) to extract the register and login parts by request.getServletPath() instead.


Strategy pattern

The Action should follow the Strategy pattern. It needs to be defined as an abstract/interface type which should do the work based on the passed-in arguments of the abstract method (this is the difference with the Command pattern, wherein the abstract/interface type should do the work based on the arguments which are been passed-in during the creation of the implementation).

public interface Action {
    public String execute(HttpServletRequest request, HttpServletResponse response) throws Exception;
}

You may want to make the Exception more specific with a custom exception like ActionException. It's just a basic kickoff example, the rest is all up to you.

Here's an example of a LoginAction which (as its name says) logs in the user. The User itself is in turn a Data Model. The View is aware of the presence of the User.

public class LoginAction implements Action {

    public String execute(HttpServletRequest request, HttpServletResponse response) throws Exception {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        User user = userDAO.find(username, password);

        if (user != null) {
            request.getSession().setAttribute("user", user); // Login user.
            return "home"; // Redirect to home page.
        }
        else {
            request.setAttribute("error", "Unknown username/password. Please retry."); // Store error message in request scope.
            return "login"; // Go back to redisplay login form with error.
        }
    }

}

Factory method pattern

The ActionFactory should follow the Factory method pattern. Basically, it should provide a creational method which returns a concrete implementation of an abstract/interface type. In this case, it should return an implementation of the Action interface based on the information provided by the request. For example, the method and pathinfo (the pathinfo is the part after the context and servlet path in the request URL, excluding the query string).

public static Action getAction(HttpServletRequest request) {
    return actions.get(request.getMethod() + request.getPathInfo());
}

The actions in turn should be some static/applicationwide Map<String, Action> which holds all known actions. It's up to you how to fill this map. Hardcoding:

actions.put("POST/register", new RegisterAction());
actions.put("POST/login", new LoginAction());
actions.put("GET/logout", new LogoutAction());
// ...

Or configurable based on a properties/XML configuration file in the classpath: (pseudo)

for (Entry entry : configuration) {
    actions.put(entry.getKey(), Class.forName(entry.getValue()).newInstance());
}

Or dynamically based on a scan in the classpath for classes implementing a certain interface and/or annotation: (pseudo)

for (ClassFile classFile : classpath) {
    if (classFile.isInstanceOf(Action.class)) {
       actions.put(classFile.getAnnotation("mapping"), classFile.newInstance());
    }
}

Keep in mind to create a "do nothing" Action for the case there's no mapping. Let it for example return directly the request.getPathInfo().substring(1) then.


Other patterns

Those were the important patterns so far.

To get a step further, you could use the Facade pattern to create a Context class which in turn wraps the request and response objects and offers several convenience methods delegating to the request and response objects and pass that as argument into the Action#execute() method instead. This adds an extra abstract layer to hide the raw Servlet API away. You should then basically end up with zero import javax.servlet.* declarations in every Action implementation. In JSF terms, this is what the FacesContext and ExternalContext classes are doing. You can find a concrete example in this answer.

Then there's the State pattern for the case that you'd like to add an extra abstraction layer to split the tasks of gathering the request parameters, converting them, validating them, updating the model values and execute the actions. In JSF terms, this is what the LifeCycle is doing.

Then there's the Composite pattern for the case that you'd like to create a component based view which can be attached with the model and whose behaviour depends on the state of the request based lifecycle. In JSF terms, this is what the UIComponent represent.

This way you can evolve bit by bit towards a component based framework.


See also:

Determining if Swift dictionary contains key and obtaining any of its values

Here is what works for me on Swift 3

let _ = (dict[key].map { $0 as? String } ?? "")

Error: Selection does not contain a main type

I ran into the same issue and found that there was an extra pair of braces (curly brackets) enclosing public static void main(String args) { ... }. This method should really be at the top scope in the class and should not be enclosed around braces. It seems that it is possible to end up with braces around this method when working in Eclipse. This could be just one way you can see this issue when working with Eclipse. Happy coding!

How can I safely create a nested directory?

import os
if os.path.isfile(filename):
    print "file exists"
else:
    "Your code here"

Where your code here is use the (touch) command

This will check if the file is there if it is not then it will create it.

How can I make my website's background transparent without making the content (images & text) transparent too?

Just include following in your code

<body background="C:\Users\Desktop\images.jpg"> 

if you want to specify the size and opacity you can use following

<p><img style="opacity:0.9;" src="C:\Users\Desktop\images.jpg" width="300" height="231" alt="Image" /></p> 

Immutable vs Mutable types

The goal of this answer is to create a single place to find all the good ideas about how to tell if you are dealing with mutating/nonmutating (immutable/mutable), and where possible, what to do about it? There are times when mutation is undesirable and python's behavior in this regard can feel counter-intuitive to coders coming into it from other languages.

As per a useful post by @mina-gabriel:

Analyzing the above and combining w/ a post by @arrakëën:

What cannot change unexpectedly?

  • scalars (variable types storing a single value) do not change unexpectedly
    • numeric examples: int(), float(), complex()
  • there are some "mutable sequences":
    • str(), tuple(), frozenset(), bytes()

What can?

  • list like objects (lists, dictionaries, sets, bytearray())
  • a post on here also says classes and class instances but this may depend on what the class inherits from and/or how its built.

by "unexpectedly" I mean that programmers from other languages might not expect this behavior (with the exception or Ruby, and maybe a few other "Python like" languages).

Adding to this discussion:

This behavior is an advantage when it prevents you from accidentally populating your code with mutliple copies of memory-eating large data structures. But when this is undesirable, how do we get around it?

With lists, the simple solution is to build a new one like so:

list2 = list(list1)

with other structures ... the solution can be trickier. One way is to loop through the elements and add them to a new empty data structure (of the same type).

functions can mutate the original when you pass in mutable structures. How to tell?

  • There are some tests given on other comments on this thread but then there are comments indicating these tests are not full proof
  • object.function() is a method of the original object but only some of these mutate. If they return nothing, they probably do. One would expect .append() to mutate without testing it given its name. .union() returns the union of set1.union(set2) and does not mutate. When in doubt, the function can be checked for a return value. If return = None, it does not mutate.
  • sorted() might be a workaround in some cases. Since it returns a sorted version of the original, it can allow you to store a non-mutated copy before you start working on the original in other ways. However, this option assumes you don't care about the order of the original elements (if you do, you need to find another way). In contrast .sort() mutates the original (as one might expect).

Non-standard Approaches (in case helpful): Found this on github published under an MIT license:

  • github repository under: tobgu named: pyrsistent
  • What it is: Python persistent data structure code written to be used in place of core data structures when mutation is undesirable

For custom classes, @semicolon suggests checking if there is a __hash__ function because mutable objects should generally not have a __hash__() function.

This is all I have amassed on this topic for now. Other ideas, corrections, etc. are welcome. Thanks.

How can I stop a While loop?

I would do it using a for loop as shown below :

def determine_period(universe_array):
    tmp = universe_array
    for period in xrange(1, 13):
        tmp = apply_rules(tmp)
        if numpy.array_equal(tmp, universe_array):
            return period
    return 0

How to list records with date from the last 10 days?

Just generalising the query if you want to work with any given date instead of current date:

SELECT Table.date
  FROM Table 
  WHERE Table.date > '2020-01-01'::date - interval '10 day'

Reload an iframe with jQuery

Here is another way

$( '#iframe' ).attr( 'src', function () { return $( this )[0].src; } );

How to check if the key pressed was an arrow key in Java KeyListener?

You should be using things like: KeyEvent.VK_UP instead of the actual code.

How are you wanting to refactor it? What is the goal of the refactoring?

Python 3.4.0 with MySQL database

for fedora and python3 use: dnf install mysql-connector-python3

How to convert Double to int directly?

int average_in_int = ( (Double) Math.ceil( sum/count ) ).intValue();

How do I find my host and username on mysql?

The default username is root. You can reset the root password if you do not know it: http://dev.mysql.com/doc/refman/5.0/en/resetting-permissions.html. You should not, however, use the root account from PHP, set up a limited permission user to do that: http://dev.mysql.com/doc/refman/5.1/en/adding-users.html

If MySql is running on the same computer as your webserver, you can just use "localhost" as the host

How can I convert ticks to a date format?

Answers so far helped me come up with mine. I'm wary of UTC vs local time; ticks should always be UTC IMO.

public class Time
{
    public static void Timestamps()
    {
        OutputTimestamp();
        Thread.Sleep(1000);
        OutputTimestamp();
    }

    private static void OutputTimestamp()
    {
        var timestamp = DateTime.UtcNow.Ticks;
        var localTicks = DateTime.Now.Ticks;
        var localTime = new DateTime(timestamp, DateTimeKind.Utc).ToLocalTime();
        Console.Out.WriteLine("Timestamp = {0}.  Local ticks = {1}.  Local time = {2}.", timestamp, localTicks, localTime);
    }
}

Output:

Timestamp = 636988286338754530.  Local ticks = 636988034338754530.  Local time = 2019-07-15 4:03:53 PM.
Timestamp = 636988286348878736.  Local ticks = 636988034348878736.  Local time = 2019-07-15 4:03:54 PM.

PHP PDO: charset, set names?

Prior to PHP 5.3.6, the charset option was ignored. If you're running an older version of PHP, you must do it like this:

<?php

    $dbh = new PDO("mysql:$connstr",  $user, $password);

    $dbh -> exec("set names utf8");

?>

How to rename JSON key

By using map function you can do that. Please refer below code.

var userDetails = [{
  "_id":"5078c3a803ff4197dc81fbfb",
  "email":"[email protected]",
  "image":"some_image_url",
  "name":"Name 1"
},{
  "_id":"5078c3a803ff4197dc81fbfc",
  "email":"[email protected]",
  "image":"some_image_url",
  "name":"Name 2"
}];

var formattedUserDetails = userDetails.map(({ _id:id, email, image, name }) => ({
  id,
  email,
  image,
  name
}));
console.log(formattedUserDetails);

Can't resolve module (not found) in React.js

I faced the same issue when I created a new react app, I tried all options in https://github.com/facebook/create-react-app/issues/2534 but it didn't help. I had to change the port for the new app and then it worked. By default, apps use the port 3000.I changed the port to 8001 in package.json as follows:

  "scripts": {
    "start": "PORT=8001 react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },

How do I test a website using XAMPP?

Just edit the httpd-vhost-conf scroll to the bottom and on the last example/demo for creating a virtual host, remove the hash-tags for DocumentRoot and ServerName. You may have hash-tags just before the <VirtualHost *.80> and </VirtualHost>

After DocumentRoot, just add the path to your web-docs ... and add your domain-name after ServerNmane

<VirtualHost *:80>
    ##ServerAdmin [email protected]
    DocumentRoot "C:/xampp/htdocs/www"
    ServerName example.com
    ##ErrorLog "logs/dummy-host2.example.com-error.log"
    ##CustomLog "logs/dummy-host2.example.com-access.log" common
</VirtualHost>

Be sure to create the www folder under htdocs. You do not have to name the folder www but I did just to be simple about it. Be sure to restart Apache and bang! you can now store files in the newly created directory. To test things out just create a simple index.html or index.php file and place in the www folder, then go to your browser and test it out localhost/ ... Note: if your server is serving php files over html then remember to add localhost/index.html if the html file is the one you choose to use for this test.

Something I should add, in order to still have access to the xampp homepage then you will need to create another VirtualHost. To do this just add

<VirtualHost *:80>
    ##ServerAdmin [email protected]
    DocumentRoot "C:/xampp/htdocs"
    ServerName htdocs.example.com
    ##ErrorLog "logs/dummy-host2.example.com-error.log"
    ##CustomLog "logs/dummy-host2.example.com-access.log" common
</VirtualHost>

underneath the last VirtualHost that you created. Next make the necessary changes to your host file and restart Apache. Now go to your browser and visit htdocs.example.com and your all set.

FFmpeg: How to split video efficiently?

Here's a useful script, it helps you split automatically: A script for splitting videos using ffmpeg

#!/bin/bash
 
# Written by Alexis Bezverkhyy <[email protected]> in 2011
# This is free and unencumbered software released into the public domain.
# For more information, please refer to <http://unlicense.org/>
 
function usage {
        echo "Usage : ffsplit.sh input.file chunk-duration [output-filename-format]"
        echo -e "\t - input file may be any kind of file reconginzed by ffmpeg"
        echo -e "\t - chunk duration must be in seconds"
        echo -e "\t - output filename format must be printf-like, for example myvideo-part-%04d.avi"
        echo -e "\t - if no output filename format is given, it will be computed\
 automatically from input filename"
}
 
IN_FILE="$1"
OUT_FILE_FORMAT="$3"
typeset -i CHUNK_LEN
CHUNK_LEN="$2"
 
DURATION_HMS=$(ffmpeg -i "$IN_FILE" 2>&1 | grep Duration | cut -f 4 -d ' ')
DURATION_H=$(echo "$DURATION_HMS" | cut -d ':' -f 1)
DURATION_M=$(echo "$DURATION_HMS" | cut -d ':' -f 2)
DURATION_S=$(echo "$DURATION_HMS" | cut -d ':' -f 3 | cut -d '.' -f 1)
let "DURATION = ( DURATION_H * 60 + DURATION_M ) * 60 + DURATION_S"
 
if [ "$DURATION" = '0' ] ; then
        echo "Invalid input video"
        usage
        exit 1
fi
 
if [ "$CHUNK_LEN" = "0" ] ; then
        echo "Invalid chunk size"
        usage
        exit 2
fi
 
if [ -z "$OUT_FILE_FORMAT" ] ; then
        FILE_EXT=$(echo "$IN_FILE" | sed 's/^.*\.\([a-zA-Z0-9]\+\)$/\1/')
        FILE_NAME=$(echo "$IN_FILE" | sed 's/^\(.*\)\.[a-zA-Z0-9]\+$/\1/')
        OUT_FILE_FORMAT="${FILE_NAME}-%03d.${FILE_EXT}"
        echo "Using default output file format : $OUT_FILE_FORMAT"
fi
 
N='1'
OFFSET='0'
let 'N_FILES = DURATION / CHUNK_LEN + 1'
 
while [ "$OFFSET" -lt "$DURATION" ] ; do
        OUT_FILE=$(printf "$OUT_FILE_FORMAT" "$N")
        echo "writing $OUT_FILE ($N/$N_FILES)..."
        ffmpeg -i "$IN_FILE" -vcodec copy -acodec copy -ss "$OFFSET" -t "$CHUNK_LEN" "$OUT_FILE"
        let "N = N + 1"
        let "OFFSET = OFFSET + CHUNK_LEN"
done

How to call a C# function from JavaScript?

A modern approach is to use ASP.NET Web API 2 (server-side) with jQuery Ajax (client-side).

Like page methods and ASMX web methods, Web API allows you to write C# code in ASP.NET which can be called from a browser or from anywhere, really!

Here is an example Web API controller, which exposes API methods allowing clients to retrieve details about 1 or all products (in the real world, products would likely be loaded from a database):

public class ProductsController : ApiController
{
    Product[] products = new Product[] 
    { 
        new Product { Id = 1, Name = "Tomato Soup", Category = "Groceries", Price = 1 }, 
        new Product { Id = 2, Name = "Yo-yo", Category = "Toys", Price = 3.75M }, 
        new Product { Id = 3, Name = "Hammer", Category = "Hardware", Price = 16.99M } 
    };

    [Route("api/products")]
    [HttpGet]
    public IEnumerable<Product> GetAllProducts()
    {
        return products;
    }

    [Route("api/product/{id}")]
    [HttpGet]
    public IHttpActionResult GetProduct(int id)
    {
        var product = products.FirstOrDefault((p) => p.Id == id);
        if (product == null)
        {
            return NotFound();
        }
        return Ok(product);
    }
}

The controller uses this example model class:

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Category { get; set; }
    public decimal Price { get; set; }
}

Example jQuery Ajax call to get and iterate over a list of products:

$(document).ready(function () {
    // Send an AJAX request
    $.getJSON("/api/products")
        .done(function (data) {
            // On success, 'data' contains a list of products.
            $.each(data, function (key, item) {
                // Add a list item for the product.
                $('<li>', { text: formatItem(item) }).appendTo($('#products'));
            });
        });
});

Not only does this allow you to easily create a modern Web API, you can if you need to get really professional and document it too, using ASP.NET Web API Help Pages and/or Swashbuckle.

Web API can be retro-fitted (added) to an existing ASP.NET Web Forms project. In that case you will need to add routing instructions into the Application_Start method in the file Global.asax:

RouteTable.Routes.MapHttpRoute(
    name: "DefaultApi",
    routeTemplate: "api/{controller}/{id}",
    defaults: new { id = System.Web.Http.RouteParameter.Optional }
);

Documentation

Vue.JS: How to call function after page loaded?

// vue js provides us `mounted()`. this means `onload` in javascript.

mounted () {
  // we can implement any method here like
   sampleFun () {
      // this is the sample method you can implement whatever you want
   }
}

How to make audio autoplay on chrome

temp fix

$(document).on('click', "#buttonStarter", function(evt)
{
var context = new AudioContext();
document.getElementById('audioPlayer').play();
$("#buttonStarter").hide()
$("#Game").show()
});

Or use a custom player to trigger play http://zohararad.github.io/audio5js/

Note : Autoplay will be renabled in 31 December

Check if the number is integer

If you prefer not to write your own function, try check.integer from package installr. Currently it uses VitoshKa's answer.

Also try check.numeric(v, only.integer=TRUE) from package varhandle, which has the benefit of being vectorized.

How to write trycatch in R

Since I just lost two days of my life trying to solve for tryCatch for an irr function, I thought I should share my wisdom (and what is missing). FYI - irr is an actual function from FinCal in this case where got errors in a few cases on a large data set.

  1. Set up tryCatch as part of a function. For example:

    irr2 <- function (x) {
      out <- tryCatch(irr(x), error = function(e) NULL)
      return(out)
    }
    
  2. For the error (or warning) to work, you actually need to create a function. I originally for error part just wrote error = return(NULL) and ALL values came back null.

  3. Remember to create a sub-output (like my "out") and to return(out).

How do I check how many options there are in a dropdown menu?

Use the length property or the size method to find out how many items are in a jQuery collection. Use the descendant selector to select all <option>'s within a <select>.

HTML:

<select id="myDropDown">
<option>1</option>
<option>2</option>
.
.
.
</select>

JQuery:

var numberOfOptions = $('select#myDropDown option').length

And a quick note, often you will need to do something in jquery for a very specific thing, but you first need to see if the very specific thing exists. The length property is the perfect tool. example:

   if($('#myDropDown option').length > 0{
      //do your stuff..
    } 

This 'translates' to "If item with ID=myDropDown has any descendent 'option' s, go do what you need to do.

Valid characters of a hostname?

If you're registering a domain and the termination (ex .com) it is not IDN, as Aaron Hathaway said: Hostnames are composed of series of labels concatenated with dots, as are all domain names. For example, en.wikipedia.org is a hostname. Each label must be between 1 and 63 characters long, and the entire hostname (including the delimiting dots but not a trailing dot) has a maximum of 253 ASCII characters.

The Internet standards (Requests for Comments) for protocols mandate that component hostname labels may contain only the ASCII letters a through z (in a case-insensitive manner), the digits 0 through 9, and the hyphen -. The original specification of hostnames in RFC 952, mandated that labels could not start with a digit or with a hyphen, and must not end with a hyphen. However, a subsequent specification (RFC 1123) permitted hostname labels to start with digits. No other symbols, punctuation characters, or white space are permitted.

Later, Spain with it's .es, .com.es, .org.es, .nom,es, .gob.es and .edu.es introduced IDN tlds, if your tld is one of .es or any other that supports it, any character can be used, but you can't combine alphabets like Latin, Greek or Cyril in one hostname, and that it respects the things that can't go at the start or at the end.

If you're using non-registered tlds, just for local networking, like with local DNS or with hosts files, you can treat them all as IDN.

Keep in mind some programs could not work well, especially old, outdated and unpopular ones.

Java reverse an int value without using array

A method to get the greatest power of ten smaller or equal to an integer: (in recursion)

public static int powerOfTen(int n) {
    if ( n < 10)
        return 1;
    else
        return 10 * powerOfTen(n/10); 
}

The method to reverse the actual integer:(in recursion)

public static int reverseInteger(int i) {
    if (i / 10 < 1)
        return i ;
    else
        return i%10*powerOfTen(i) + reverseInteger(i/10);
}

Disable Laravel's Eloquent timestamps

If you are using 5.5.x:

const UPDATED_AT = null;

And for 'created_at' field, you can use:

const CREATED_AT = null;

Make sure you are on the newest version. (This was broken in Laravel 5.5.0 and fixed again in 5.5.5).

Replace the single quote (') character from a string

As for how to represent a single apostrophe as a string in Python, you can simply surround it with double quotes ("'") or you can escape it inside single quotes ('\'').

To remove apostrophes from a string, a simple approach is to just replace the apostrophe character with an empty string:

>>> "didn't".replace("'", "")
'didnt'

Connect Android to WiFi Enterprise network EAP(PEAP)

Thanks for enlightening us Cypawer.

I also tried this app https://play.google.com/store/apps/details?id=com.oneguyinabasement.leapwifi

and it worked flawlessly.

Leap Wifi Connector

How to set selected item of Spinner by value, not by position?

Here is my hopefully complete solution. I have following enum:

public enum HTTPMethod {GET, HEAD}

used in following class

public class WebAddressRecord {
...
public HTTPMethod AccessMethod = HTTPMethod.HEAD;
...

Code to set the spinner by HTTPMethod enum-member:

    Spinner mySpinner = (Spinner) findViewById(R.id.spinnerHttpmethod);
    ArrayAdapter<HTTPMethod> adapter = new ArrayAdapter<HTTPMethod>(this, android.R.layout.simple_spinner_item, HTTPMethod.values());
    mySpinner.setAdapter(adapter);
    int selectionPosition= adapter.getPosition(webAddressRecord.AccessMethod);
    mySpinner.setSelection(selectionPosition);

Where R.id.spinnerHttpmethod is defined in a layout-file, and android.R.layout.simple_spinner_item is delivered by android-studio.

Performing user authentication in Java EE / JSF using j_security_check

I suppose you want form based authentication using deployment descriptors and j_security_check.

You can also do this in JSF by just using the same predefinied field names j_username and j_password as demonstrated in the tutorial.

E.g.

<form action="j_security_check" method="post">
    <h:outputLabel for="j_username" value="Username" />
    <h:inputText id="j_username" />
    <br />
    <h:outputLabel for="j_password" value="Password" />
    <h:inputSecret id="j_password" />
    <br />
    <h:commandButton value="Login" />
</form>

You could do lazy loading in the User getter to check if the User is already logged in and if not, then check if the Principal is present in the request and if so, then get the User associated with j_username.

package com.stackoverflow.q2206911;

import java.io.IOException;
import java.security.Principal;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
import javax.faces.context.FacesContext;

@ManagedBean
@SessionScoped
public class Auth {

    private User user; // The JPA entity.

    @EJB
    private UserService userService;

    public User getUser() {
        if (user == null) {
            Principal principal = FacesContext.getCurrentInstance().getExternalContext().getUserPrincipal();
            if (principal != null) {
                user = userService.find(principal.getName()); // Find User by j_username.
            }
        }
        return user;
    }

}

The User is obviously accessible in JSF EL by #{auth.user}.

To logout do a HttpServletRequest#logout() (and set User to null!). You can get a handle of the HttpServletRequest in JSF by ExternalContext#getRequest(). You can also just invalidate the session altogether.

public String logout() {
    FacesContext.getCurrentInstance().getExternalContext().invalidateSession();
    return "login?faces-redirect=true";
}

For the remnant (defining users, roles and constraints in deployment descriptor and realm), just follow the Java EE 6 tutorial and the servletcontainer documentation the usual way.


Update: you can also use the new Servlet 3.0 HttpServletRequest#login() to do a programmatic login instead of using j_security_check which may not per-se be reachable by a dispatcher in some servletcontainers. In this case you can use a fullworthy JSF form and a bean with username and password properties and a login method which look like this:

<h:form>
    <h:outputLabel for="username" value="Username" />
    <h:inputText id="username" value="#{auth.username}" required="true" />
    <h:message for="username" />
    <br />
    <h:outputLabel for="password" value="Password" />
    <h:inputSecret id="password" value="#{auth.password}" required="true" />
    <h:message for="password" />
    <br />
    <h:commandButton value="Login" action="#{auth.login}" />
    <h:messages globalOnly="true" />
</h:form>

And this view scoped managed bean which also remembers the initially requested page:

@ManagedBean
@ViewScoped
public class Auth {

    private String username;
    private String password;
    private String originalURL;

    @PostConstruct
    public void init() {
        ExternalContext externalContext = FacesContext.getCurrentInstance().getExternalContext();
        originalURL = (String) externalContext.getRequestMap().get(RequestDispatcher.FORWARD_REQUEST_URI);

        if (originalURL == null) {
            originalURL = externalContext.getRequestContextPath() + "/home.xhtml";
        } else {
            String originalQuery = (String) externalContext.getRequestMap().get(RequestDispatcher.FORWARD_QUERY_STRING);

            if (originalQuery != null) {
                originalURL += "?" + originalQuery;
            }
        }
    }

    @EJB
    private UserService userService;

    public void login() throws IOException {
        FacesContext context = FacesContext.getCurrentInstance();
        ExternalContext externalContext = context.getExternalContext();
        HttpServletRequest request = (HttpServletRequest) externalContext.getRequest();

        try {
            request.login(username, password);
            User user = userService.find(username, password);
            externalContext.getSessionMap().put("user", user);
            externalContext.redirect(originalURL);
        } catch (ServletException e) {
            // Handle unknown username/password in request.login().
            context.addMessage(null, new FacesMessage("Unknown login"));
        }
    }

    public void logout() throws IOException {
        ExternalContext externalContext = FacesContext.getCurrentInstance().getExternalContext();
        externalContext.invalidateSession();
        externalContext.redirect(externalContext.getRequestContextPath() + "/login.xhtml");
    }

    // Getters/setters for username and password.
}

This way the User is accessible in JSF EL by #{user}.

How can I convert a std::string to int?

It's probably a bit of overkill, but boost::lexical_cast<int>( theString ) should to the job quite well.

Effective swapping of elements of an array in Java

Nope. You could have a function to make it more concise each place you use it, but in the end, the work done would be the same (plus the overhead of the function call, until/unless HotSpot moved it inline — to help it with that, make the functon static final).

Connect to docker container as user other than root

This solved my use case that is: "Compile webpack stuff in nodejs container on Windows running Docker Desktop with WSL2 and have the built assets under your currently logged in user."

docker run -u 1000 -v "$PWD":/build -w /build node:10.23 /bin/sh -c 'npm install && npm run build'

Based on the answer by eigenfield. Thank you!

Also this material helped me understand what is going on.

Aren't Python strings immutable? Then why does a + " " + b work?

First a pointed to the string "Dog". Then you changed the variable a to point at a new string "Dog eats treats". You didn't actually mutate the string "Dog". Strings are immutable, variables can point at whatever they want.

Using Ansible set_fact to create a dictionary from register results

I think I got there in the end.

The task is like this:

- name: Populate genders
  set_fact:
    genders: "{{ genders|default({}) | combine( {item.item.name: item.stdout} ) }}"
  with_items: "{{ people.results }}"

It loops through each of the dicts (item) in the people.results array, each time creating a new dict like {Bob: "male"}, and combine()s that new dict in the genders array, which ends up like:

{
    "Bob": "male",
    "Thelma": "female"
}

It assumes the keys (the name in this case) will be unique.


I then realised I actually wanted a list of dictionaries, as it seems much easier to loop through using with_items:

- name: Populate genders
  set_fact:
    genders: "{{ genders|default([]) + [ {'name': item.item.name, 'gender': item.stdout} ] }}"
  with_items: "{{ people.results }}"

This keeps combining the existing list with a list containing a single dict. We end up with a genders array like this:

[
    {'name': 'Bob', 'gender': 'male'},
    {'name': 'Thelma', 'gender': 'female'}
]

ssh: The authenticity of host 'hostname' can't be established

I had the same error and wanted to draw attention to the fact that - as it just happened to me - you might just have wrong privileges.
You've set up your .ssh directory as either regular or root user and thus you need to be the correct user. When this error appeared, I was root but I configured .ssh as regular user. Exiting root fixed it.

Skip a submodule during a Maven build

Maven version 3.2.1 added this feature, you can use the -pl switch (shortcut for --projects list) with ! or - (source) to exclude certain submodules.

mvn -pl '!submodule-to-exclude' install
mvn -pl -submodule-to-exclude install

Be careful in bash the character ! is a special character, so you either have to single quote it (like I did) or escape it with the backslash character.

The syntax to exclude multiple module is the same as the inclusion

mvn -pl '!submodule1,!submodule2' install
mvn -pl -submodule1,-submodule2 install

EDIT Windows does not seem to like the single quotes, but it is necessary in bash ; in Windows, use double quotes (thanks @awilkinson)

mvn -pl "!submodule1,!submodule2" install

LaTeX table positioning

You may want to add this to your preamble, and adjust the values as necessary:

 %------------begin Float Adjustment
%two column float page must be 90% full
\renewcommand\dblfloatpagefraction{.90}
%two column top float can cover up to 80% of page
\renewcommand\dbltopfraction{.80}
%float page must be 90% full
\renewcommand\floatpagefraction{.90}
%top float can cover up to 80% of page
\renewcommand\topfraction{.80}
%bottom float can cover up to 80% of page
\renewcommand\bottomfraction{.80}
%at least 10% of a normal page must contain text
\renewcommand\textfraction{.1}
%separation between floats and text
\setlength\dbltextfloatsep{9pt plus 5pt minus 3pt }
%separation between two column floats and text
\setlength\textfloatsep{4pt plus 2pt minus 1.5pt}

Particularly, the \floatpagefraction may be of interest.

to_string not declared in scope

This error, as correctly identified above, is due to the compiler not using c++11 or above standard. This answer is for Windows 10.

For c++11 and above standard support in codeblocks version 17:

  1. Click settings in the toolbar.

  2. A drop-down menu appears. Select compiler option.

  3. Choose Global Compiler Settings.

  4. In the toolbar in this new window in second section, choose compiler settings.

  5. Then choose compiler flags option in below toolbar.

  6. Unfold general tab. Check the C++ standard that you want your compiler to follow.

  7. Click OK.

For those who are trying to get C++11 support in Sublime text.

  1. Download mingw compiler version 7 or above. In versions below this, the default c++ standard used is c++98 whereas in versions higher than 7, the default standard used is c++11.

  2. Copy the folder in main C drive. It should not be inside any other folder in C drive.

  3. Rename the folder as MinGW. This name is case insensitive, so it should any variation of mingw and must not include any other characters in the name.

  4. Then go to environment variables and edit the path variable. Add this "C:\mingw\bin" and click OK.

  5. You can check the version of g++ in cmd by typing g++ -v.

  6. This should be sufficient to enable c++11 in sublime text.

If you want to take inputs and outputs as well from input files for competitive programming purposes, then follow this link.

'ssh-keygen' is not recognized as an internal or external command

If you have installed Git, and is installed at C:\Program Files, follow as below

  1. Go to "C:\Program Files\Git"
  2. Run git-bash.exe, this opens a new window
  3. In the new bash window, run "ssh-keygen -t rsa -C""
  4. It prompts for file in which to save key, dont input any value - just press enter
  5. Same for passphrase (twice), just press enter
  6. id_rsa and id_rsa.pub will be generated in your home folder under .ssh

What is a wrapper class?

There are several design patterns that can be called wrapper classes.

See my answer to "How do the Proxy, Decorator, Adaptor, and Bridge Patterns differ?"

Determining the size of an Android view at runtime

I was also lost around getMeasuredWidth() and getMeasuredHeight() getHeight() and getWidth() for a long time.......... later i found that getting the view's width and height in onSizeChanged() is the best way to do this........ you can dynamically get your CURRENT width and CURRENT height of your view by overriding the onSizeChanged() method.

might wanna take a look at this which has an elaborate code snippet. New Blog Post: how to get width and height dimensions of a customView (extends View) in Android http://syedrakibalhasan.blogspot.com/2011/02/how-to-get-width-and-height-dimensions.html

R Not in subset

The expression df1$id %in% idNums1 produces a logical vector. To negate it, you need to negate the whole vector:

!(df1$id %in% idNums1)

iOS app with framework crashed on device, dyld: Library not loaded, Xcode 6 Beta

In the target's General tab, there is an Embedded Binaries field. When you add the framework there the crash is resolved.

Reference is here on Apple Developer Forums.