Programs & Examples On #Z axis

Rotating a Vector in 3D Space

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

Rotation in 2D

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

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

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

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

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

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

Rotation in 3D

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

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

around the Y-axis would be

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

around the X-axis would be

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

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

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

I hope this clarifies basic rotation.

Rotation not Revolution

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

Composition

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

Rotation around Arbitrary Vector

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

How to get a parent element to appear above child

Set a negative z-index for the child, and remove the one set on the parent.

_x000D_
_x000D_
.parent {_x000D_
    position: relative;_x000D_
    width: 350px;_x000D_
    height: 150px;_x000D_
    background: red;_x000D_
    border: solid 1px #000;_x000D_
}_x000D_
.parent2 {_x000D_
    position: relative;_x000D_
    width: 350px;_x000D_
    height: 40px;_x000D_
    background: red;_x000D_
    border: solid 1px #000;_x000D_
}_x000D_
.child {_x000D_
    position: relative;_x000D_
    background-color: blue;_x000D_
    height: 200px;_x000D_
}_x000D_
.wrapper {_x000D_
    position: relative;_x000D_
    background: green;_x000D_
    height: 350px;_x000D_
}
_x000D_
<div class="wrapper">_x000D_
    <div class="parent">parent 1 parent 1_x000D_
        <div class="child">child child child</div>_x000D_
    </div>_x000D_
    <div class="parent2">parent 2 parent 2_x000D_
    </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

https://jsfiddle.net/uov5h84f/

Android: combining text & image on a Button or ImageButton

enter image description here

     <Button
            android:layout_width="0dp"
            android:layout_weight="1"
            android:background="@drawable/home_button"
            android:drawableLeft="@android:drawable/ic_menu_edit"
            android:drawablePadding="6dp"
            android:gravity="left|center"
            android:height="60dp"
            android:padding="6dp"
            android:text="AndroidDhina"
            android:textColor="#000"
            android:textStyle="bold" />

PHP returning JSON to JQUERY AJAX CALL

You can return json in PHP this way:

header('Content-Type: application/json');
echo json_encode(array('foo' => 'bar'));
exit;

EXEC sp_executesql with multiple parameters

Here is a simple example:

EXEC sp_executesql @sql, N'@p1 INT, @p2 INT, @p3 INT', @p1, @p2, @p3;

Your call will be something like this

EXEC sp_executesql @statement, N'@LabID int, @BeginDate date, @EndDate date, @RequestTypeID varchar', @LabID, @BeginDate, @EndDate, @RequestTypeID

Where is Maven Installed on Ubuntu

Here is a bash script for newer Maven copy and paste it...

# @author Yucca Nel

#!/bin/sh

#This installs maven2 & a default JDK 
sudo apt-get install maven2;

#Makes the /usr/lib/mvn in case...
sudo mkdir -p /usr/lib/mvn;

#Clean out /tmp...
sudo rm -rf /tmp/*;
cd /tmp;

#Update this line to reflect newer versions of maven
wget http://mirrors.powertech.no/www.apache.org/dist//maven/binaries/apache-maven-3.0.3-bin.tar.gz;
tar -xvf ./*gz;

#Move it to where it to logical location
sudo mv /tmp/apache-maven-3.* /usr/lib/mvn/;

#Link the new Maven to the bin... (update for higher/newer version)...
sudo ln -s /usr/lib/mvn/apache-maven-3.0.3/bin/mvn /usr/bin/mvn;

#test
mvn -version;

exit 0;

Copy table to a different database on a different SQL Server

Create the database, with Script Database as... CREATE To

Within SSMS on the source server, use the export wizard with the destination server database as the destination.

  • Source instance > YourDatabase > Tasks > Export data
  • Data Soure = SQL Server Native Client
    • Validate/enter Server & Database
  • Destination = SQL Server Native Client
    • Validate/enter Server & Database
  • Follow through wizard

What does the "yield" keyword do?

What does the yield keyword do in Python?

Answer Outline/Summary

  • A function with yield, when called, returns a Generator.
  • Generators are iterators because they implement the iterator protocol, so you can iterate over them.
  • A generator can also be sent information, making it conceptually a coroutine.
  • In Python 3, you can delegate from one generator to another in both directions with yield from.
  • (Appendix critiques a couple of answers, including the top one, and discusses the use of return in a generator.)

Generators:

yield is only legal inside of a function definition, and the inclusion of yield in a function definition makes it return a generator.

The idea for generators comes from other languages (see footnote 1) with varying implementations. In Python's Generators, the execution of the code is frozen at the point of the yield. When the generator is called (methods are discussed below) execution resumes and then freezes at the next yield.

yield provides an easy way of implementing the iterator protocol, defined by the following two methods: __iter__ and next (Python 2) or __next__ (Python 3). Both of those methods make an object an iterator that you could type-check with the Iterator Abstract Base Class from the collections module.

>>> def func():
...     yield 'I am'
...     yield 'a generator!'
... 
>>> type(func)                 # A function with yield is still a function
<type 'function'>
>>> gen = func()
>>> type(gen)                  # but it returns a generator
<type 'generator'>
>>> hasattr(gen, '__iter__')   # that's an iterable
True
>>> hasattr(gen, 'next')       # and with .next (.__next__ in Python 3)
True                           # implements the iterator protocol.

The generator type is a sub-type of iterator:

>>> import collections, types
>>> issubclass(types.GeneratorType, collections.Iterator)
True

And if necessary, we can type-check like this:

>>> isinstance(gen, types.GeneratorType)
True
>>> isinstance(gen, collections.Iterator)
True

A feature of an Iterator is that once exhausted, you can't reuse or reset it:

>>> list(gen)
['I am', 'a generator!']
>>> list(gen)
[]

You'll have to make another if you want to use its functionality again (see footnote 2):

>>> list(func())
['I am', 'a generator!']

One can yield data programmatically, for example:

def func(an_iterable):
    for item in an_iterable:
        yield item

The above simple generator is also equivalent to the below - as of Python 3.3 (and not available in Python 2), you can use yield from:

def func(an_iterable):
    yield from an_iterable

However, yield from also allows for delegation to subgenerators, which will be explained in the following section on cooperative delegation with sub-coroutines.

Coroutines:

yield forms an expression that allows data to be sent into the generator (see footnote 3)

Here is an example, take note of the received variable, which will point to the data that is sent to the generator:

def bank_account(deposited, interest_rate):
    while True:
        calculated_interest = interest_rate * deposited 
        received = yield calculated_interest
        if received:
            deposited += received


>>> my_account = bank_account(1000, .05)

First, we must queue up the generator with the builtin function, next. It will call the appropriate next or __next__ method, depending on the version of Python you are using:

>>> first_year_interest = next(my_account)
>>> first_year_interest
50.0

And now we can send data into the generator. (Sending None is the same as calling next.) :

>>> next_year_interest = my_account.send(first_year_interest + 1000)
>>> next_year_interest
102.5

Cooperative Delegation to Sub-Coroutine with yield from

Now, recall that yield from is available in Python 3. This allows us to delegate coroutines to a subcoroutine:


def money_manager(expected_rate):
    # must receive deposited value from .send():
    under_management = yield                   # yield None to start.
    while True:
        try:
            additional_investment = yield expected_rate * under_management 
            if additional_investment:
                under_management += additional_investment
        except GeneratorExit:
            '''TODO: write function to send unclaimed funds to state'''
            raise
        finally:
            '''TODO: write function to mail tax info to client'''
        

def investment_account(deposited, manager):
    '''very simple model of an investment account that delegates to a manager'''
    # must queue up manager:
    next(manager)      # <- same as manager.send(None)
    # This is where we send the initial deposit to the manager:
    manager.send(deposited)
    try:
        yield from manager
    except GeneratorExit:
        return manager.close()  # delegate?

And now we can delegate functionality to a sub-generator and it can be used by a generator just as above:

my_manager = money_manager(.06)
my_account = investment_account(1000, my_manager)
first_year_return = next(my_account) # -> 60.0

Now simulate adding another 1,000 to the account plus the return on the account (60.0):

next_year_return = my_account.send(first_year_return + 1000)
next_year_return # 123.6

You can read more about the precise semantics of yield from in PEP 380.

Other Methods: close and throw

The close method raises GeneratorExit at the point the function execution was frozen. This will also be called by __del__ so you can put any cleanup code where you handle the GeneratorExit:

my_account.close()

You can also throw an exception which can be handled in the generator or propagated back to the user:

import sys
try:
    raise ValueError
except:
    my_manager.throw(*sys.exc_info())

Raises:

Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
  File "<stdin>", line 6, in money_manager
  File "<stdin>", line 2, in <module>
ValueError

Conclusion

I believe I have covered all aspects of the following question:

What does the yield keyword do in Python?

It turns out that yield does a lot. I'm sure I could add even more thorough examples to this. If you want more or have some constructive criticism, let me know by commenting below.


Appendix:

Critique of the Top/Accepted Answer**

  • It is confused on what makes an iterable, just using a list as an example. See my references above, but in summary: an iterable has an __iter__ method returning an iterator. An iterator provides a .next (Python 2 or .__next__ (Python 3) method, which is implicitly called by for loops until it raises StopIteration, and once it does, it will continue to do so.
  • It then uses a generator expression to describe what a generator is. Since a generator is simply a convenient way to create an iterator, it only confuses the matter, and we still have not yet gotten to the yield part.
  • In Controlling a generator exhaustion he calls the .next method, when instead he should use the builtin function, next. It would be an appropriate layer of indirection, because his code does not work in Python 3.
  • Itertools? This was not relevant to what yield does at all.
  • No discussion of the methods that yield provides along with the new functionality yield from in Python 3. The top/accepted answer is a very incomplete answer.

Critique of answer suggesting yield in a generator expression or comprehension.

The grammar currently allows any expression in a list comprehension.

expr_stmt: testlist_star_expr (annassign | augassign (yield_expr|testlist) |
                     ('=' (yield_expr|testlist_star_expr))*)
...
yield_expr: 'yield' [yield_arg]
yield_arg: 'from' test | testlist

Since yield is an expression, it has been touted by some as interesting to use it in comprehensions or generator expression - in spite of citing no particularly good use-case.

The CPython core developers are discussing deprecating its allowance. Here's a relevant post from the mailing list:

On 30 January 2017 at 19:05, Brett Cannon wrote:

On Sun, 29 Jan 2017 at 16:39 Craig Rodrigues wrote:

I'm OK with either approach. Leaving things the way they are in Python 3 is no good, IMHO.

My vote is it be a SyntaxError since you're not getting what you expect from the syntax.

I'd agree that's a sensible place for us to end up, as any code relying on the current behaviour is really too clever to be maintainable.

In terms of getting there, we'll likely want:

  • SyntaxWarning or DeprecationWarning in 3.7
  • Py3k warning in 2.7.x
  • SyntaxError in 3.8

Cheers, Nick.

-- Nick Coghlan | ncoghlan at gmail.com | Brisbane, Australia

Further, there is an outstanding issue (10544) which seems to be pointing in the direction of this never being a good idea (PyPy, a Python implementation written in Python, is already raising syntax warnings.)

Bottom line, until the developers of CPython tell us otherwise: Don't put yield in a generator expression or comprehension.

The return statement in a generator

In Python 2:

In a generator function, the return statement is not allowed to include an expression_list. In that context, a bare return indicates that the generator is done and will cause StopIteration to be raised.

An expression_list is basically any number of expressions separated by commas - essentially, in Python 2, you can stop the generator with return, but you can't return a value.

In Python 3:

In a generator function, the return statement indicates that the generator is done and will cause StopIteration to be raised. The returned value (if any) is used as an argument to construct StopIteration and becomes the StopIteration.value attribute.

Footnotes

  1. The languages CLU, Sather, and Icon were referenced in the proposal to introduce the concept of generators to Python. The general idea is that a function can maintain internal state and yield intermediate data points on demand by the user. This promised to be superior in performance to other approaches, including Python threading, which isn't even available on some systems.

  2. This means, for example, that range objects aren't Iterators, even though they are iterable, because they can be reused. Like lists, their __iter__ methods return iterator objects.

yield was originally introduced as a statement, meaning that it could only appear at the beginning of a line in a code block. Now yield creates a yield expression. https://docs.python.org/2/reference/simple_stmts.html#grammar-token-yield_stmt This change was proposed to allow a user to send data into the generator just as one might receive it. To send data, one must be able to assign it to something, and for that, a statement just won't work.

Difference between using gradlew and gradle

The difference lies in the fact that ./gradlew indicates you are using a gradle wrapper. The wrapper is generally part of a project and it facilitates installation of gradle. If you were using gradle without the wrapper you would have to manually install it - for example, on a mac brew install gradle and then invoke gradle using the gradle command. In both cases you are using gradle, but the former is more convenient and ensures version consistency across different machines.

Each Wrapper is tied to a specific version of Gradle, so when you first run one of the commands above for a given Gradle version, it will download the corresponding Gradle distribution and use it to execute the build.

Not only does this mean that you don’t have to manually install Gradle yourself, but you are also sure to use the version of Gradle that the build is designed for. This makes your historical builds more reliable

Read more here - https://docs.gradle.org/current/userguide/gradle_wrapper.html

Also, Udacity has a neat, high level video explaining the concept of the gradle wrapper - https://www.youtube.com/watch?v=1aA949H-shk

How to execute Ant build in command line

Try running all targets individually to check that all are running correct

run ant target name to run a target individually

e.g. ant build-project

Also the default target you specified is

project basedir="." default="build" name="iControlSilk4J"

This will only execute build-subprojects,build-project and init

SOAP request in PHP with CURL

Tested and working!

  • with https, user & password

     <?php 
     //Data, connection, auth
     $dataFromTheForm = $_POST['fieldName']; // request data from the form
     $soapUrl = "https://connecting.website.com/soap.asmx?op=DoSomething"; // asmx URL of WSDL
     $soapUser = "username";  //  username
     $soapPassword = "password"; // password
    
     // xml post structure
    
     $xml_post_string = '<?xml version="1.0" encoding="utf-8"?>
                         <soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
                           <soap:Body>
                             <GetItemPrice xmlns="http://connecting.website.com/WSDL_Service"> // xmlns value to be set to your WSDL URL
                               <PRICE>'.$dataFromTheForm.'</PRICE> 
                             </GetItemPrice >
                           </soap:Body>
                         </soap:Envelope>';   // data from the form, e.g. some ID number
    
        $headers = array(
                     "Content-type: text/xml;charset=\"utf-8\"",
                     "Accept: text/xml",
                     "Cache-Control: no-cache",
                     "Pragma: no-cache",
                     "SOAPAction: http://connecting.website.com/WSDL_Service/GetPrice", 
                     "Content-length: ".strlen($xml_post_string),
                 ); //SOAPAction: your op URL
    
         $url = $soapUrl;
    
         // PHP cURL  for https connection with auth
         $ch = curl_init();
         curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
         curl_setopt($ch, CURLOPT_URL, $url);
         curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
         curl_setopt($ch, CURLOPT_USERPWD, $soapUser.":".$soapPassword); // username and password - declared at the top of the doc
         curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
         curl_setopt($ch, CURLOPT_TIMEOUT, 10);
         curl_setopt($ch, CURLOPT_POST, true);
         curl_setopt($ch, CURLOPT_POSTFIELDS, $xml_post_string); // the SOAP request
         curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    
         // converting
         $response = curl_exec($ch); 
         curl_close($ch);
    
         // converting
         $response1 = str_replace("<soap:Body>","",$response);
         $response2 = str_replace("</soap:Body>","",$response1);
    
         // convertingc to XML
         $parser = simplexml_load_string($response2);
         // user $parser to get your data out of XML response and to display it. 
     ?>
    

Access denied for user 'root'@'localhost' with PHPMyAdmin

Edit your phpmyadmin config.inc.php file and if you have Password, insert that in front of Password in following code:

$cfg['Servers'][$i]['verbose'] = 'localhost';
$cfg['Servers'][$i]['host'] = 'localhost';
$cfg['Servers'][$i]['port'] = '3306';
$cfg['Servers'][$i]['socket'] = '';
$cfg['Servers'][$i]['connect_type'] = 'tcp';
$cfg['Servers'][$i]['extension'] = 'mysqli';
$cfg['Servers'][$i]['auth_type'] = 'config';
$cfg['Servers'][$i]['user'] = '**your-root-username**';
$cfg['Servers'][$i]['password'] = '**root-password**';
$cfg['Servers'][$i]['AllowNoPassword'] = true;

How to keep footer at bottom of screen

Perhaps the easiest is to use position: absolute to fix to the bottom, then a suitable margin/padding to make sure that the other text doesn't spill over the top of it.

css:

<style>
  body {
    margin: 0 0 20px;
  }
  .footer {
    position: absolute;
    bottom: 0;
    height: 20px;
    background: #f0f0f0;
    width: 100%;
  }
</style>

Here is the html main content.

<div class="footer"> Here is the footer. </div>

When using SASS how can I import a file from a different directory?

Looks like some changes to SASS have made possible what you've initially tried doing:

@import "../subdir/common";

We even got this to work for some totally unrelated folder located in c:\projects\sass:

@import "../../../../../../../../../../projects/sass/common";

Just add enough ../ to be sure you'll end up at the drive root and you're good to go.

Of course, this solution is far from pretty, but I couldn't get an import from a totally different folder to work, neither using I c:\projects\sass nor setting the environment variable SASS_PATH (from: :load_paths reference) to that same value.

Passing a variable from one php include file to another: global vs. not

Here is a pitfall to avoid. In case you need to access your variable $name within a function, you need to say "global $name;" at the beginning of that function. You need to repeat this for each function in the same file.

include('front.inc');
global $name;

function foo() {
  echo $name;
}

function bar() {
  echo $name;
}

foo();
bar();

will only show errors. The correct way to do that would be:

include('front.inc');

function foo() {
  global $name;
  echo $name;
}

function bar() {
  global $name;
  echo $name;
}

foo();
bar();

Why cannot change checkbox color whatever I do?

you cant change the background of checkbox but some how you can do a trick try this :)

_x000D_
_x000D_
.divBox {_x000D_
    width: 20px;_x000D_
    height: 20px;_x000D_
    background: #ddd;_x000D_
    margin: 20px 90px;_x000D_
    position: relative;_x000D_
    -webkit-box-shadow: 0px 1px 3px rgba(0,0,0,0.5);_x000D_
    -moz-box-shadow: 0px 1px 3px rgba(0,0,0,0.5);_x000D_
    box-shadow: 0px 1px 3px rgba(0,0,0,0.5);_x000D_
}_x000D_
_x000D_
.divBox label {_x000D_
    display: block;_x000D_
    width: 20px;_x000D_
    height: 20px;_x000D_
    -webkit-transition: all .5s ease;_x000D_
    -moz-transition: all .5s ease;_x000D_
    -o-transition: all .5s ease;_x000D_
    -ms-transition: all .5s ease;_x000D_
    transition: all .5s ease;_x000D_
    cursor: pointer;_x000D_
    position: absolute;_x000D_
    top: 1px;_x000D_
    z-index: 1;_x000D_
    /* _x000D_
    use this background transparent to check the value of checkbox _x000D_
    background: transparent;_x000D_
    */_x000D_
    background: Black;_x000D_
    -webkit-box-shadow:inset 0px 1px 3px rgba(0,0,0,0.5);_x000D_
    -moz-box-shadow:inset 0px 1px 3px rgba(0,0,0,0.5);_x000D_
    box-shadow:inset 0px 1px 3px rgba(0,0,0,0.5);_x000D_
}_x000D_
_x000D_
.divBox input[type=checkbox]:checked + label {_x000D_
    background: green;_x000D_
}
_x000D_
<div class="divBox">_x000D_
    <input type="checkbox" value="1" id="checkboxFourInput"name="" />_x000D_
    <label for="checkboxFourInput"></label>_x000D_
</div>
_x000D_
_x000D_
_x000D_

How to install a specific version of a ruby gem?

For installing gem install gemname -v versionnumber

For uninstall gem uninstall gemname -v versionnumber

How do I get Flask to run on port 80?

Easiest and Best Solution

Save your .py file in a folder. This case my folder name is test. In the command prompt run the following

c:\test> set FLASK_APP=application.py
c:\test> set FLASK_RUN_PORT=8000
c:\test> flask run

----------------- Following will be returned ----------------

 * Serving Flask app "application.py"
 * Environment: production
   WARNING: Do not use the development server in a production environment.
   Use a production WSGI server instead.
 * Debug mode: off
 * Running on http://127.0.0.1:8000/ (Press CTRL+C to quit)
127.0.0.1 - - [23/Aug/2019 09:40:04] "[37mGET / HTTP/1.1[0m" 200 -
127.0.0.1 - - [23/Aug/2019 09:40:04] "[33mGET /favicon.ico HTTP/1.1[0m" 404 -

Now on your browser type: http://127.0.0.1:8000. Thanks

Name does not exist in the current context

Jobs.aspx

This is the phyiscal file -> CodeFile="Jobs.aspx.cs"

This is the class which handles the events of the page -> Inherits="Members_Jobs"

Jobs.aspx.cs

This is the partial class which manages the page events -> public partial class Members_Jobs : System.Web.UI.Page

The other part of the partial class should be -> public partial class Members_Jobs this is usually the designer file.

you dont need to have partial classes and could declare your controls all in 1 class and not have a designer file.

EDIT 27/09/2013 11:37

if you are still having issues with this I would do as Bharadwaj suggested and delete the designer file. You can then right-click on the page, in the solution explorer, and there is an option, something like "Convert to Web Application", which will regenerate your designer file

How to query nested objects?

The two query mechanism work in different ways, as suggested in the docs at the section Subdocuments:

When the field holds an embedded document (i.e, subdocument), you can either specify the entire subdocument as the value of a field, or “reach into” the subdocument using dot notation, to specify values for individual fields in the subdocument:

Equality matches within subdocuments select documents if the subdocument matches exactly the specified subdocument, including the field order.


In the following example, the query matches all documents where the value of the field producer is a subdocument that contains only the field company with the value 'ABC123' and the field address with the value '123 Street', in the exact order:

db.inventory.find( {
    producer: {
        company: 'ABC123',
        address: '123 Street'
    }
});

How to vertically center a "div" element for all browsers using CSS?

Declare this Mixin:

@mixin vertical-align($position: relative) {
  position: $position;
  top: 50%;
  -webkit-transform: translateY(-50%);
  -ms-transform: translateY(-50%);
  transform: translateY(-50%);
}

Then include it in your element:

.element{
    @include vertical-align();
}

How do I detect if a user is already logged in Firebase?

This works:

async function IsLoggedIn(): Promise<boolean> {
  try {
    await new Promise((resolve, reject) =>
      app.auth().onAuthStateChanged(
        user => {
          if (user) {
            // User is signed in.
            resolve(user)
          } else {
            // No user is signed in.
            reject('no user logged in')
          }
        },
        // Prevent console error
        error => reject(error)
      )
    )
    return true
  } catch (error) {
    return false
  }
}

Populate unique values into a VBA array from Excel

Combining the Dictionary approach from Tim with the variant array from Jean_Francois below.

The array you want is in objDict.keys

enter image description here

Sub A_Unique_B()
Dim X
Dim objDict As Object
Dim lngRow As Long

Set objDict = CreateObject("Scripting.Dictionary")
X = Application.Transpose(Range([a1], Cells(Rows.Count, "A").End(xlUp)))

For lngRow = 1 To UBound(X, 1)
    objDict(X(lngRow)) = 1
Next
Range("B1:B" & objDict.Count) = Application.Transpose(objDict.keys)
End Sub

C# how to wait for a webpage to finish loading before continuing

Assuming the "commit" element represents a standard Form submit button then you can attach an event handler to the WebBrowsers Navigated event.

Javascript: 'window' is not defined

It is from an external js file and it is the only file linked to the page.

OK.

When I double click this file I get the following error

Sounds like you're double-clicking/running a .js file, which will attempt to run the script outside the browser, like a command line script. And that would explain this error:

Windows Script Host Error: 'window' is not defined Code: 800A1391

... not an error you'll see in a browser. And of course, the browser is what supplies the window object.

ADDENDUM: As a course of action, I'd suggest opening the relevant HTML file and taking a peek at the console. If you don't see anything there, it's likely your window.onload definition is simply being hit after the browser fires the window.onload event.

Hide particular div onload and then show div after click

$(document).ready(function() {
    $('#div2').hide(0);
    $('#preview').on('click', function() {
        $('#div1').hide(300, function() { // first hide div1
            // then show div2
            $('#div2').show(300);
        });     
    });
});

You missed # before div2

Working Sample

How to properly override clone method?

The way your code works is pretty close to the "canonical" way to write it. I'd throw an AssertionError within the catch, though. It signals that that line should never be reached.

catch (CloneNotSupportedException e) {
    throw new AssertionError(e);
}

How to modify the nodejs request default timeout time?

Try this:

var options = {
    url:  'http://url',
    timeout: 120000
}

request(options, function(err, resp, body) {});

Refer to request's documentation for other options.

jQuery - find child with a specific class

$(this).find(".bgHeaderH2").html();

or

$(this).find(".bgHeaderH2").text();

How to launch an Activity from another Application in Android

Steps to launch new activity as follows:

1.Get intent for package

2.If intent is null redirect user to playstore

3.If intent is not null open activity

public void launchNewActivity(Context context, String packageName) {
    Intent intent = null;
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.CUPCAKE) {
        intent = context.getPackageManager().getLaunchIntentForPackage(packageName);
    }
    if (intent == null) {
        try {
            intent = new Intent(Intent.ACTION_VIEW);
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            intent.setData(Uri.parse("market://details?id=" + packageName));
            context.startActivity(intent);
        } catch (android.content.ActivityNotFoundException anfe) {
            startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("https://play.google.com/store/apps/details?id=" + packageName)));
        }
    } else {
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(intent);
    }
}

Right HTTP status code to wrong input

409 Conflict could be an acceptable solution.

According to: https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html

The request could not be completed due to a conflict with the current state of the resource. This code is only allowed in situations where it is expected that the user might be able to resolve the conflict and resubmit the request. The response body SHOULD include enough information for the user to recognize the source of the conflict. Ideally, the response entity would include enough information for the user or user agent to fix the problem; however, that might not be possible and is not required.

The doc continues with an example:

Conflicts are most likely to occur in response to a PUT request. For example, if versioning were being used and the entity being PUT included changes to a resource which conflict with those made by an earlier (third-party) request, the server might use the 409 response to indicate that it can't complete the request. In this case, the response entity would likely contain a list of the differences between the two versions in a format defined by the response Content-Type.


In my case, I would like to PUT a string, that must be unique, to a database via an API. Before adding it to the database, I am checking that it is not already in the database.

If it is, I will return "Error: The string is already in the database", 409.

I believe this is what the OP wanted: an error code suitable for when the data does not pass the server's criteria.

no debugging symbols found when using gdb

I know this was answered a long time ago, but I've recently spent hours trying to solve a similar problem. The setup is local PC running Debian 8 using Eclipse CDT Neon.2, remote ARM7 board (Olimex) running Debian 7. Tool chain is Linaro 4.9 using gdbserver on the remote board and the Linaro GDB on the local PC. My issue was that the debug session would start and the program would execute, but breakpoints did not work and when manually paused "no source could be found" would result. My compile line options (Linaro gcc) included -ggdb -O0 as many have suggested but still the same problem. Ultimately I tried gdb proper on the remote board and it complained of no symbols. The curious thing was that 'file' reported debug not stripped on the target executable.

I ultimately solved the problem by adding -g to the linker options. I won't claim to fully understand why this helped, but I wanted to pass this on for others just in case it helps. In this case Linux did indeed need -g on the linker options.

How do I get video durations with YouTube API version 3?

You can get the duration from the 'contentDetails' field in the json response.

enter image description here

How to part DATE and TIME from DATETIME in MySQL

For only date use
date("Y-m-d");

and for only time use
date("H:i:s");

Tomcat view catalina.out log file

Try using this:

sudo tail -f /opt/tomcat/logs/catalina.out

How to establish a connection pool in JDBC?

I would recommend using the commons-dbcp library. There are numerous examples listed on how to use it, here is the link to the move simple one. The usage is very simple:

 BasicDataSource ds = new BasicDataSource();
 ds.setDriverClassName("oracle.jdbc.driver.OracleDriver")
 ds.setUsername("scott");
 ds.setPassword("tiger");
 ds.setUrl(connectURI);
 ...
 Connection conn = ds.getConnection();

You only need to create the data source once, so make sure you read the documentation if you do not know how to do that. If you are not aware of how to properly write JDBC statements so you do not leak resources, you also might want to read this Wikipedia page.

Pandas: drop a level from a multi-level column index?

I have struggled with this problem since I don’t know why my droplevel() function does not work. Work through several and learn that ‘a’ in your table is columns name and ‘b’, ‘c’ are index. Do like this will help

df.columns.name = None
df.reset_index() #make index become label

Open multiple Projects/Folders in Visual Studio Code

Not sure why the simplest solution is not mentioned. You can simply do File>New Window and open the other project in the new window.

How can I add comments in MySQL?

You can use single line comments:

-- this is a comment
# this is also a comment

Or a multiline comment:

/*
   multiline
   comment
*/

Latex Remove Spaces Between Items in List

compactitem does the job.

\usepackage{paralist}

...

\begin{compactitem}[$\bullet$]
    \item Element 1
    \item Element 2
\end{compactitem}
\vspace{\baselineskip} % new line after list

ALTER TABLE ADD COLUMN IF NOT EXISTS in SQLite

In case you're having this problem in flex/adobe air and find yourself here first, i've found a solution, and have posted it on a related question: ADD COLUMN to sqlite db IF NOT EXISTS - flex/air sqlite?

My comment here: https://stackoverflow.com/a/24928437/2678219

How can I develop for iPhone using a Windows development machine?

So the bad news is that XCode is needed for its iOS Simulator as well as its Application Loader facility for actually uploading the programs to iOS devices for "real" testing. You'll need XCode for signing your apps before submitting to the App Store. Unfortunately, XCode is only available for OS X.

However, the good news is that you may be able to purchase OS X and run it in a virtual machine such as VMWare Workstation. I don't know how straightforward this is, as it is rather difficult to get OS X to run on non-Apple hardware, but a quick Google search shows that it is possible. This method would (likely) be cheaper than purchasing a new Mac, although the Mac Mini retails in the US for only $599. Some posts I've seen indicate that this may or may not be legal, others say you need OS X Server for virtualization. I'll leave the research up to you.

There are also services such as MacInCloud that allow you to rent a Mac server that you can access from Windows via remote desktop, or through your browser. Unfortunately, I don't think you'd be able to use Application Loader, as you have to physically connect the device to your computer, but it would work for development and simulation, at least.

Good luck!

How to call a C# function from JavaScript?

Server-side functions are on the server-side, client-side functions reside on the client. What you can do is you have to set hidden form variable and submit the form, then on page use Page_Load handler you can access value of variable and call the server method.

More info can be found here and here

How do I use cx_freeze?

find the cxfreeze script and run it. It will be in the same path as your other python helper scripts, such as pip.

cxfreeze Main.py --target-dir dist

read more at: http://cx-freeze.readthedocs.org/en/latest/script.html#script

MySQL: How to copy rows, but change a few fields?

As long as Event_ID is Integer, do this:

INSERT INTO Table (foo, bar, Event_ID)
SELECT foo, bar, (Event_ID + 155)
  FROM Table
WHERE Event_ID = "120"

ERROR: ld.so: object LD_PRELOAD cannot be preloaded: ignored

Thanks for the responses. I think I've solved the problem just now.

Since LD_PRELOAD is for setting some library proloaded, I check the library that ld preloads with LD_PRELOAD, one of which is "liblunar-calendar-preload.so", that is not existing in the path "/usr/lib/liblunar-calendar-preload.so", but I find a similar library "liblunar-calendar-preload-2.0.so", which is a difference version of the former one.

Then I guess maybe liblunar-calendar-preload.so was updated to a 2.0 version when the system updated, leaving LD_PRELOAD remain to be "/usr/lib/liblunar-calendar-preload.so". Thus the preload library name was not updated to the newest version.

To avoid changing environment variable, I create a symbolic link under the path "/usr/lib"

sudo ln -s liblunar-calendar-preload-2.0.so liblunar-calendar-preload.so

Then I restart bash, the error is gone.

In C++, what is a virtual base class?

Diamond inheritance runnable usage example

This example shows how to use a virtual base class in the typical scenario: to solve diamond inheritance problems.

Consider the following working example:

main.cpp

#include <cassert>

class A {
    public:
        A(){}
        A(int i) : i(i) {}
        int i;
        virtual int f() = 0;
        virtual int g() = 0;
        virtual int h() = 0;
};

class B : public virtual A {
    public:
        B(int j) : j(j) {}
        int j;
        virtual int f() { return this->i + this->j; }
};

class C : public virtual A {
    public:
        C(int k) : k(k) {}
        int k;
        virtual int g() { return this->i + this->k; }
};

class D : public B, public C {
    public:
        D(int i, int j, int k) : A(i), B(j), C(k) {}
        virtual int h() { return this->i + this->j + this->k; }
};

int main() {
    D d = D(1, 2, 4);
    assert(d.f() == 3);
    assert(d.g() == 5);
    assert(d.h() == 7);
}

Compile and run:

g++ -ggdb3 -O0 -std=c++11 -Wall -Wextra -pedantic -o main.out main.cpp
./main.out

If we remove the virtual into:

class B : public virtual A

we would get a wall of errors about GCC being unable to resolve D members and methods that were inherited twice via A:

main.cpp:27:7: warning: virtual base ‘A’ inaccessible in ‘D’ due to ambiguity [-Wextra]
   27 | class D : public B, public C {
      |       ^
main.cpp: In member function ‘virtual int D::h()’:
main.cpp:30:40: error: request for member ‘i’ is ambiguous
   30 |         virtual int h() { return this->i + this->j + this->k; }
      |                                        ^
main.cpp:7:13: note: candidates are: ‘int A::i’
    7 |         int i;
      |             ^
main.cpp:7:13: note:                 ‘int A::i’
main.cpp: In function ‘int main()’:
main.cpp:34:20: error: invalid cast to abstract class type ‘D’
   34 |     D d = D(1, 2, 4);
      |                    ^
main.cpp:27:7: note:   because the following virtual functions are pure within ‘D’:
   27 | class D : public B, public C {
      |       ^
main.cpp:8:21: note:    ‘virtual int A::f()’
    8 |         virtual int f() = 0;
      |                     ^
main.cpp:9:21: note:    ‘virtual int A::g()’
    9 |         virtual int g() = 0;
      |                     ^
main.cpp:34:7: error: cannot declare variable ‘d’ to be of abstract type ‘D’
   34 |     D d = D(1, 2, 4);
      |       ^
In file included from /usr/include/c++/9/cassert:44,
                 from main.cpp:1:
main.cpp:35:14: error: request for member ‘f’ is ambiguous
   35 |     assert(d.f() == 3);
      |              ^
main.cpp:8:21: note: candidates are: ‘virtual int A::f()’
    8 |         virtual int f() = 0;
      |                     ^
main.cpp:17:21: note:                 ‘virtual int B::f()’
   17 |         virtual int f() { return this->i + this->j; }
      |                     ^
In file included from /usr/include/c++/9/cassert:44,
                 from main.cpp:1:
main.cpp:36:14: error: request for member ‘g’ is ambiguous
   36 |     assert(d.g() == 5);
      |              ^
main.cpp:9:21: note: candidates are: ‘virtual int A::g()’
    9 |         virtual int g() = 0;
      |                     ^
main.cpp:24:21: note:                 ‘virtual int C::g()’
   24 |         virtual int g() { return this->i + this->k; }
      |                     ^
main.cpp:9:21: note:                 ‘virtual int A::g()’
    9 |         virtual int g() = 0;
      |                     ^
./main.out

Tested on GCC 9.3.0, Ubuntu 20.04.

Using .otf fonts on web browsers

You can implement your OTF font using @font-face like:

@font-face {
    font-family: GraublauWeb;
    src: url("path/GraublauWeb.otf") format("opentype");
}

@font-face {
    font-family: GraublauWeb;
    font-weight: bold;
    src: url("path/GraublauWebBold.otf") format("opentype");
}

// Edit: OTF now works in most browsers, see comments

However if you want to support a wide variety of browsers i would recommend you to switch to WOFF and TTF font types. WOFF type is implemented by every major desktop browser, while the TTF type is a fallback for older Safari, Android and iOS browsers. If your font is a free font, you could convert your font using for example a transfonter.

@font-face {
    font-family: GraublauWeb;
    src: url("path/GraublauWebBold.woff") format("woff"), url("path/GraublauWebBold.ttf")  format("truetype");
}

If you want to support nearly every browser that is still out there (not necessary anymore IMHO), you should add some more font-types like:

@font-face {
    font-family: GraublauWeb;
    src: url("webfont.eot"); /* IE9 Compat Modes */
    src: url("webfont.eot?#iefix") format("embedded-opentype"), /* IE6-IE8 */
         url("webfont.woff") format("woff"), /* Modern Browsers */
         url("webfont.ttf")  format("truetype"), /* Safari, Android, iOS */
         url("webfont.svg#svgFontName") format("svg"); /* Legacy iOS */
}

You can read more about why all these types are implemented and their hacks here. To get a detailed view of which file-types are supported by which browsers, see:

@font-face Browser Support

EOT Browser Support

WOFF Browser Support

TTF Browser Support

SVG-Fonts Browser Support

hope this helps

HttpServletRequest - how to obtain the referring URL?

It's available in the HTTP referer header. You can get it in a servlet as follows:

String referrer = request.getHeader("referer"); // Yes, with the legendary misspelling.

You, however, need to realize that this is a client-controlled value and can thus be spoofed to something entirely different or even removed. Thus, whatever value it returns, you should not use it for any critical business processes in the backend, but only for presentation control (e.g. hiding/showing/changing certain pure layout parts) and/or statistics.

For the interested, background about the misspelling can be found in Wikipedia.

Git - fatal: Unable to create '/path/my_project/.git/index.lock': File exists

In Windows, I only managed to be able to delete the lock file after Ending Task for all Git Windows (32bit) processes in the Task Manager.

Solution (Win 10)

1. End Task for all Git Windows (32bit) processes in the Task Manager

2. Delete the .git/index.lock file

How to check cordova android version of a cordova/phonegap project?

Run

cordova -v 

to see the currently running version. Run the npm info command

npm info cordova

for a longer listing that includes the current version along with other available version numbers

Uncaught TypeError: Cannot read property 'msie' of undefined - jQuery tools

Use the following script tag in your jsp/js file:

<script src="http://code.jquery.com/jquery-1.9.0.js"></script>
<script src="http://code.jquery.com/jquery-migrate-1.2.1.js"></script>

this will work for sure.

A non-blocking read on a subprocess.PIPE in Python

This solution uses the select module to "read any available data" from an IO stream. This function blocks initially until data is available, but then reads only the data that is available and doesn't block further.

Given the fact that it uses the select module, this only works on Unix.

The code is fully PEP8-compliant.

import select


def read_available(input_stream, max_bytes=None):
    """
    Blocks until any data is available, then all available data is then read and returned.
    This function returns an empty string when end of stream is reached.

    Args:
        input_stream: The stream to read from.
        max_bytes (int|None): The maximum number of bytes to read. This function may return fewer bytes than this.

    Returns:
        str
    """
    # Prepare local variables
    input_streams = [input_stream]
    empty_list = []
    read_buffer = ""

    # Initially block for input using 'select'
    if len(select.select(input_streams, empty_list, empty_list)[0]) > 0:

        # Poll read-readiness using 'select'
        def select_func():
            return len(select.select(input_streams, empty_list, empty_list, 0)[0]) > 0

        # Create while function based on parameters
        if max_bytes is not None:
            def while_func():
                return (len(read_buffer) < max_bytes) and select_func()
        else:
            while_func = select_func

        while True:
            # Read single byte at a time
            read_data = input_stream.read(1)
            if len(read_data) == 0:
                # End of stream
                break
            # Append byte to string buffer
            read_buffer += read_data
            # Check if more data is available
            if not while_func():
                break

    # Return read buffer
    return read_buffer

Print array to a file

You can try this, $myArray as the Array

$filename = "mylog.txt";
$text = "";
foreach($myArray as $key => $value)
{
    $text .= $key." : ".$value."\n";
}
$fh = fopen($filename, "w") or die("Could not open log file.");
fwrite($fh, $text) or die("Could not write file!");
fclose($fh);

What's "P=NP?", and why is it such a famous question?

To give the simplest answer I can think of:

Suppose we have a problem that takes a certain number of inputs, and has various potential solutions, which may or may not solve the problem for given inputs. A logic puzzle in a puzzle magazine would be a good example: the inputs are the conditions ("George doesn't live in the blue or green house"), and the potential solution is a list of statements ("George lives in the yellow house, grows peas, and owns the dog"). A famous example is the Traveling Salesman problem: given a list of cities, and the times to get from any city to any other, and a time limit, a potential solution would be a list of cities in the order the salesman visits them, and it would work if the sum of the travel times was less than the time limit.

Such a problem is in NP if we can efficiently check a potential solution to see if it works. For example, given a list of cities for the salesman to visit in order, we can add up the times for each trip between cities, and easily see if it's under the time limit. A problem is in P if we can efficiently find a solution if one exists.

(Efficiently, here, has a precise mathematical meaning. Practically, it means that large problems aren't unreasonably difficult to solve. When searching for a possible solution, an inefficient way would be to list all possible potential solutions, or something close to that, while an efficient way would require searching a much more limited set.)

Therefore, the P=NP problem can be expressed this way: If you can verify a solution for a problem of the sort described above efficiently, can you find a solution (or prove there is none) efficiently? The obvious answer is "Why should you be able to?", and that's pretty much where the matter stands today. Nobody has been able to prove it one way or another, and that bothers a lot of mathematicians and computer scientists. That's why anybody who can prove the solution is up for a million dollars from the Claypool Foundation.

We generally assume that P does not equal NP, that there is no general way to find solutions. If it turned out that P=NP, a lot of things would change. For example, cryptography would become impossible, and with it any sort of privacy or verifiability on the Internet. After all, we can efficiently take the encrypted text and the key and produce the original text, so if P=NP we could efficiently find the key without knowing it beforehand. Password cracking would become trivial. On the other hand, there's whole classes of planning problems and resource allocation problems that we could solve effectively.

You may have heard the description NP-complete. An NP-complete problem is one that is NP (of course), and has this interesting property: if it is in P, every NP problem is, and so P=NP. If you could find a way to efficiently solve the Traveling Salesman problem, or logic puzzles from puzzle magazines, you could efficiently solve anything in NP. An NP-complete problem is, in a way, the hardest sort of NP problem.

So, if you can find an efficient general solution technique for any NP-complete problem, or prove that no such exists, fame and fortune are yours.

how to set the default value to the drop down list control?

if you know the index of the item of default value,just

lstDepartment.SelectedIndex = 1;//the second item

or if you know the value you want to set, just

lstDepartment.SelectedValue = "the value you want to set";

jQuery OR Selector?

Use a comma.

'.classA, .classB'

You may choose to omit the space.

Hadoop/Hive : Loading data from .csv on a local machine

You may try this, Following are few examples on how files are generated. Tool -- https://sourceforge.net/projects/csvtohive/?source=directory

  1. Select a CSV file using Browse and set hadoop root directory ex: /user/bigdataproject/

  2. Tool Generates Hadoop script with all csv files and following is a sample of generated Hadoop script to insert csv into Hadoop

    #!/bin/bash -v
    hadoop fs -put ./AllstarFull.csv /user/bigdataproject/AllstarFull.csv hive -f ./AllstarFull.hive

    hadoop fs -put ./Appearances.csv /user/bigdataproject/Appearances.csv hive -f ./Appearances.hive

    hadoop fs -put ./AwardsManagers.csv /user/bigdataproject/AwardsManagers.csv hive -f ./AwardsManagers.hive

  3. Sample of generated Hive scripts

    CREATE DATABASE IF NOT EXISTS lahman;
    USE lahman;
    CREATE TABLE AllstarFull (playerID string,yearID string,gameNum string,gameID string,teamID string,lgID string,GP string,startingPos string) row format delimited fields terminated by ',' stored as textfile;
    LOAD DATA INPATH '/user/bigdataproject/AllstarFull.csv' OVERWRITE INTO TABLE AllstarFull;
    SELECT * FROM AllstarFull;

Thanks Vijay

Server.MapPath("."), Server.MapPath("~"), Server.MapPath(@"\"), Server.MapPath("/"). What is the difference?

Just to expand on @splattne's answer a little:

MapPath(string virtualPath) calls the following:

public string MapPath(string virtualPath)
{
    return this.MapPath(VirtualPath.CreateAllowNull(virtualPath));
}

MapPath(VirtualPath virtualPath) in turn calls MapPath(VirtualPath virtualPath, VirtualPath baseVirtualDir, bool allowCrossAppMapping) which contains the following:

//...
if (virtualPath == null)
{
    virtualPath = VirtualPath.Create(".");
}
//...

So if you call MapPath(null) or MapPath(""), you are effectively calling MapPath(".")

How do you use math.random to generate random ints?

Cast abc to an integer.

(int)(Math.random()*100);

Get UserDetails object from Security Context in Spring MVC controller

if you are using spring security then you can get the current logged in user by

Authentication auth = SecurityContextHolder.getContext().getAuthentication();
     String name = auth.getName(); //get logged in username

How to update all MySQL table rows at the same time?

Just add parameters, split by comma:

UPDATE tablename SET column1 = "value1", column2 = "value2" ....

see the link also MySQL UPDATE

An explicit value for the identity column in table can only be specified when a column list is used and IDENTITY_INSERT is ON SQL Server

I use the following to create a temp exact as the table but without the identity:

SELECT TOP 0 CONVERT(INT,0)myid,* INTO #temp FROM originaltable

ALTER TABLE #temp DROP COLUMN id

EXEC tempdb.sys.sp_rename N'#temp.myid', N'id', N'COLUMN'

Gets a warning about renames but no big deal. I use this on production class systems. Helps make sure the copy will follow any future table modifications and the temp produced is capable of getting rows additional times within a task. Please note that the PK constraint is also removed - if you need it you can add it at the end.

Pure Javascript listen to input value change

If you would like to monitor the changes each time there is a keystroke on the keyboard.

const textarea = document.querySelector(`#string`)
textarea.addEventListener("keydown", (e) =>{
   console.log('test') 
})

How can I do string interpolation in JavaScript?

Expanding on Greg Kindel's second answer, you can write a function to eliminate some of the boilerplate:

var fmt = {
    join: function() {
        return Array.prototype.slice.call(arguments).join(' ');
    },
    log: function() {
        console.log(this.join(...arguments));
    }
}

Usage:

var age = 7;
var years = 5;
var sentence = fmt.join('I am now', age, 'years old!');
fmt.log('In', years, 'years I will be', age + years, 'years old!');

Print a string as hex bytes?

Print a string as hex bytes?

The accepted answer gives:

s = "Hello world !!"
":".join("{:02x}".format(ord(c)) for c in s)

returns:

'48:65:6c:6c:6f:20:77:6f:72:6c:64:20:21:21'

The accepted answer works only so long as you use bytes (mostly ascii characters). But if you use unicode, e.g.:

a_string = u"?????? ???!!" # "Prevyet mir", or "Hello World" in Russian.

You need to convert to bytes somehow.

If your terminal doesn't accept these characters, you can decode from UTF-8 or use the names (so you can paste and run the code along with me):

a_string = (
    "\N{CYRILLIC CAPITAL LETTER PE}"
    "\N{CYRILLIC SMALL LETTER ER}"
    "\N{CYRILLIC SMALL LETTER I}"
    "\N{CYRILLIC SMALL LETTER VE}"
    "\N{CYRILLIC SMALL LETTER IE}"
    "\N{CYRILLIC SMALL LETTER TE}"
    "\N{SPACE}"
    "\N{CYRILLIC SMALL LETTER EM}"
    "\N{CYRILLIC SMALL LETTER I}"
    "\N{CYRILLIC SMALL LETTER ER}"
    "\N{EXCLAMATION MARK}"
    "\N{EXCLAMATION MARK}"
)

So we see that:

":".join("{:02x}".format(ord(c)) for c in a_string)

returns

'41f:440:438:432:435:442:20:43c:438:440:21:21'

a poor/unexpected result - these are the code points that combine to make the graphemes we see in Unicode, from the Unicode Consortium - representing languages all over the world. This is not how we actually store this information so it can be interpreted by other sources, though.

To allow another source to use this data, we would usually need to convert to UTF-8 encoding, for example, to save this string in bytes to disk or to publish to html. So we need that encoding to convert the code points to the code units of UTF-8 - in Python 3, ord is not needed because bytes are iterables of integers:

>>> ":".join("{:02x}".format(c) for c in a_string.encode('utf-8'))
'd0:9f:d1:80:d0:b8:d0:b2:d0:b5:d1:82:20:d0:bc:d0:b8:d1:80:21:21'

Or perhaps more elegantly, using the new f-strings (only available in Python 3):

>>> ":".join(f'{c:02x}' for c in a_string.encode('utf-8'))
'd0:9f:d1:80:d0:b8:d0:b2:d0:b5:d1:82:20:d0:bc:d0:b8:d1:80:21:21'

In Python 2, pass c to ord first, i.e. ord(c) - more examples:

>>> ":".join("{:02x}".format(ord(c)) for c in a_string.encode('utf-8'))
'd0:9f:d1:80:d0:b8:d0:b2:d0:b5:d1:82:20:d0:bc:d0:b8:d1:80:21:21'
>>> ":".join(format(ord(c), '02x') for c in a_string.encode('utf-8'))
'd0:9f:d1:80:d0:b8:d0:b2:d0:b5:d1:82:20:d0:bc:d0:b8:d1:80:21:21'

Remove empty lines in a text file via grep

grep '^..' my_file

example

THIS

IS

THE

FILE

EOF_MYFILE

it gives as output only lines with at least 2 characters.

THIS
IS
THE
FILE
EOF_MYFILE

See also the results with grep '^' my_file outputs

THIS

IS

THE

FILE

EOF_MYFILE

and also with grep '^.' my_file outputs

THIS
IS
THE
FILE
EOF_MYFILE

How to use execvp()

In cpp, you need to pay special attention to string types when using execvp:

#include <iostream>
#include <string>
#include <cstring>
#include <stdio.h>
#include <unistd.h>
using namespace std;

const size_t MAX_ARGC = 15; // 1 command + # of arguments
char* argv[MAX_ARGC + 1]; // Needs +1 because of the null terminator at the end
// c_str() converts string to const char*, strdup converts const char* to char*
argv[0] = strdup(command.c_str());

// start filling up the arguments after the first command
size_t arg_i = 1;
while (cin && arg_i < MAX_ARGC) {
    string arg;
    cin >> arg;
    if (arg.empty()) {
        argv[arg_i] = nullptr;
        break;
    } else {
        argv[arg_i] = strdup(arg.c_str());
    }
    ++arg_i;
}

// Run the command with arguments
if (execvp(command.c_str(), argv) == -1) {
    // Print error if command not found
    cerr << "command '" << command << "' not found\n";
}

Reference: execlp?execvp?????

I can't delete a remote master branch on git

As explained in "Deleting your master branch" by Matthew Brett, you need to change your GitHub repo default branch.

You need to go to the GitHub page for your forked repository, and click on the “Settings” button.

Click on the "Branches" tab on the left hand side. There’s a “Default branch” dropdown list near the top of the screen.

From there, select placeholder (where placeholder is the dummy name for your new default branch).

Confirm that you want to change your default branch.

Now you can do (from the command line):

git push origin :master

Or, since 2012, you can delete that same branch directly on GitHub:

GitHub deletion

That was announced in Sept. 2013, a year after I initially wrote that answer.

For small changes like documentation fixes, typos, or if you’re just a walking software compiler, you can get a lot done in your browser without needing to clone the entire repository to your computer.


Note: for BitBucket, Tum reports in the comments:

About the same for Bitbucket

Repo -> Settings -> Repository details -> Main branch

Easy way to build Android UI?

The easiest way is with REBOL 3:

http://rebolforum.com/index.cgi?f=printtopic&permalink=Nick25-Aug-2013/10:08:38-7:00&archiveflag=new

Here are 10 fully functional demo programs, with GUIs. These run on Android and desktop OSs, using the exact same code:

REBOL []
load-gui
view [text "Hello World!"]


REBOL [title: "Tiny Note Editor"]
do %r3-gui.r3  ; download this file manually or just use load-gui as above
view [
    a1: area
    button "Save" on-action [write %notes.txt get-face a1]
    button "Load" on-action [set-face a1 to-string read %notes.txt]
]


REBOL [title: "Data Entry to CSV File"]
do %r3-gui.r3
view [
    text "First Name:"
    f1: field
    text "Last Name:"
    f2: field
    button "Submit" on-action [
        write/append %cntcts.txt rejoin [
            mold get-face f1 " " mold get-face f2 newline
        ]
        request "" "Saved"
    ]
    a1: area
    button "Load" on-action [set-face a1 to-string read %cntcts.txt]
]


REBOL [title: "Text File Reader (How to use a text list file selector)"]
do %r3-gui.r3
view [
    a1: area
    button "Load" on-action [
        files: read %./
        view/modal [
            text "File Name:"
            t2: text-list files on-action [
                set-face a1 to-string read(to-file pick files get-face t2)
                unview
            ]
        ]
    ]
]


REBOL [title: "List-View (Grid) Example"]
do %r3-gui.r3
view [
    text-table ["1" 200 "2" 100 "3"][
        ["asdf" "a" "4"]
        ["sdfg" "b" "3"]
        ["dfgh" "c" "2"]
        ["fghj" "d" "1"]
    ] 
]


REBOL [title: "Calculator"]
do %r3-gui.r3
stylize [
    btn: button [
        facets: [init-size: 50x50]
        actors: [on-action:[set-face f join get-face f get-face face]]
    ]
]
view [
    hgroup [
        f: field return
        btn "1"  btn "2"  btn "3"  btn " + "  return
        btn "4"  btn "5"  btn "6"  btn " - "  return
        btn "7"  btn "8"  btn "9"  btn " * "  return
        btn "0"  btn "."  btn " / "   btn "=" on-action [
            attempt [set-face f form do get-face f]
        ]
    ]
]


REBOL [title: "Sliding Tile Puzzle"]
do %r3-gui.r3
stylize [
    p: button [
        facets: [init-size: 60x60  max-size: 60x60]
        actors: [
            on-action: [
                t: face/gob/offset
                face/gob/offset: x/gob/offset
                x/gob/offset: t
            ]
        ]
    ]
]
view/options [
    hgroup [ 
        p "8"   p "7"   p "6"   return
        p "5"   p "4"   p "3"   return
        p "2"   p "1"   x: box 60x60 white
    ]
] [bg-color: white]


REBOL [title: "Math Test"]
do %r3-gui.r3
random/seed now
x: does [rejoin [random 10 " + " random 20]]
view [
    f1: field (x)
    text "Answer:"
    f2: field on-action [
        either (get-face f2) = (form do get-face f1) [
            request "Yes!" "Yes!"][request "No!" "No!"
        ]
        set-face f1 x
        set-face f2 ""
        focus f2
    ]
]


REBOL [title: "Minimal Cash Register"]
do %r3-gui.r3
stylize [fld: field [init-size: 80]]   
view [
    hgroup [
        text "Cashier:"   cashier: fld 
        text "Item:"      item: fld 
        text "Price:"     price: fld on-action [
            if error? try [to-money get-face price] [
                request "Error" "Price error" 
                return none
            ]
            set-face a rejoin [
                get-face a mold get-face item tab get-face price newline
            ]
            set-face item copy "" set-face price copy ""
            sum: 0
            foreach [item price] load get-face a [
                sum: sum + to-money price
            ]
            set-face subtotal form sum
            set-face tax form sum * .06
            set-face total form sum * 1.06 
            focus item
        ]
        return
        a: area 600x300
        return
        text "Subtotal:"   subtotal: fld 
        text "Tax:"        tax: fld 
        text "Total:"      total: fld
        button "Save" on-action [
            items: replace/all (mold load get-face a) newline " "
            write/append %sales.txt rejoin [
                items newline get-face cashier newline now/date newline
            ]
            set-face item copy "" set-face price copy "" 
            set-face a copy ""    set-face subtotal copy ""
            set-face tax copy "" set-face total copy ""
        ]
    ]
]


REBOL [title: "Requestors"]
do %r3-gui.r3
x: request/ask "Question" "Do you like this?."
either x = false [print "No!"] [print "Yes!"]
x: request/custom "" "Do you like this?" ["Yay" "Boo"]
either x = false [print "Boo!"] [print "Yay!"]
view [button "Click me" on-action[request "Ok" "You clicked the button."]]

Load data from txt with pandas

You can use it which is most helpful.

df = pd.read_csv(('data.txt'), sep="\t", skiprows=[0,1], names=['FromNode','ToNode'])

How to change Elasticsearch max memory size

In elasticsearch path home dir i.e. typically /usr/share/elasticsearch, There is a config file bin/elasticsearch.in.sh. Edit parameter ES_MIN_MEM, ES_MAX_MEM in this file to change -Xms2g, -Xmx4g respectively. And Please make sure you have restarted the node after this config change.

How to pass an event object to a function in Javascript?

I would change your binding to be:

<button type="button" value="click me" onclick="check_me" />

I would then change your check_me() function declaration to be:

function check_me() {   
  //event.preventDefault();
  var hello = document.myForm.username.value;
  var err = '';

  if(hello == '' || hello == null) {
    err = 'User name required';
  }

  if(err != '') { 
     alert(err); 
     $('username').focus(); 
     event.preventDefault(); 
   } else { 
    return true; }
}

Add Insecure Registry to Docker

For me the solution was to add the registry to here:

/etc/sysconfig/docker-registries

DOCKER_REGISTRIES=''
DOCKER_EXTRA_REGISTRIES='--insecure-registry  b.example.com'

How can I count text lines inside an DOM element? Can I?

No, not reliably. There are simply too many unknown variables

  1. What OS (different DPIs, font variations, etc...)?
  2. Do they have their font-size scaled up because they are practically blind?
  3. Heck, in webkit browsers, you can actually resize textboxes to your heart's desire.

The list goes on. Someday I hope there will be such a method of reliably accomplishing this with JavaScript, but until that day comes, your out of luck.

I hate these kinds of answers and I hope someone can prove me wrong.

How can I push a specific commit to a remote, and not previous commits?

You could also, in another directory:

  • git clone [your repository]
  • Overwrite the .git directory in your original repository with the .git directory of the repository you just cloned right now.
  • git add and git commit your original

How to add a spinner icon to button when it's in the Loading state?

The only thing I found that worked was a post here: https://stackoverflow.com/a/44548729/9488229

I improved it, and now it provides all these features:

  • Disable the button after click
  • Show an animated loading icon using native bootstrap
  • Re-enable the button after the page is done loading
  • Text goes back to original when page loading is done

Javascript:

$(document).ready(function () {
    $('.btn').on('click', function() {
        var e=this;
        setTimeout(function() {
            e.innerHTML='<span class="spinner-border spinner-border-sm" role="status" aria-hidden="true"></span> Searching...';
            e.disabled=true;
        },0);
        return true;
    });
});

How to Call Controller Actions using JQuery in ASP.NET MVC

We can call Controller method using Javascript / Jquery very easily as follows:

Suppose following is the Controller method to be called returning an array of some class objects. Let the class is 'A'

public JsonResult SubMenu_Click(string param1, string param2)

    {
       A[] arr = null;
        try
        {
            Processing...
           Get Result and fill arr.

        }
        catch { }


        return Json(arr , JsonRequestBehavior.AllowGet);

    }

Following is the complex type (class)

 public class A
 {

  public string property1 {get ; set ;}

  public string property2 {get ; set ;}

 }

Now it was turn to call above controller method by JQUERY. Following is the Jquery function to call the controller method.

function callControllerMethod(value1 , value2) {
    var strMethodUrl = '@Url.Action("SubMenu_Click", "Home")?param1=value1 &param2=value2'
    $.getJSON(strMethodUrl, receieveResponse);
}


function receieveResponse(response) {

    if (response != null) {
        for (var i = 0; i < response.length; i++) {
           alert(response[i].property1);
        }
    }
}

In the above Jquery function 'callControllerMethod' we develop controller method url and put that in a variable named 'strMehodUrl' and call getJSON method of Jquery API.

receieveResponse is the callback function receiving the response or return value of the controllers method.

Here we made use of JSON , since we can't make use of the C# class object

directly into the javascript function , so we converted the result (arr) in controller method into JSON object as follows:

Json(arr , JsonRequestBehavior.AllowGet);

and returned that Json object.

Now in callback function of the Javascript / JQuery we can make use of this resultant JSON object and work accordingly to show response data on UI.

For more detaill click here

Wildcards in jQuery selectors

Try the jQuery starts-with

selector, '^=', eg

[id^="jander"]

I have to ask though, why don't you want to do this using classes?

Find an element in DOM based on an attribute value

you could use getAttribute:

 var p = document.getElementById("p");
 var alignP = p.getAttribute("align");

https://developer.mozilla.org/en-US/docs/Web/API/Element/getAttribute

Visibility of global variables in imported modules

Globals in Python are global to a module, not across all modules. (Many people are confused by this, because in, say, C, a global is the same across all implementation files unless you explicitly make it static.)

There are different ways to solve this, depending on your actual use case.


Before even going down this path, ask yourself whether this really needs to be global. Maybe you really want a class, with f as an instance method, rather than just a free function? Then you could do something like this:

import module1
thingy1 = module1.Thingy(a=3)
thingy1.f()

If you really do want a global, but it's just there to be used by module1, set it in that module.

import module1
module1.a=3
module1.f()

On the other hand, if a is shared by a whole lot of modules, put it somewhere else, and have everyone import it:

import shared_stuff
import module1
shared_stuff.a = 3
module1.f()

… and, in module1.py:

import shared_stuff
def f():
    print shared_stuff.a

Don't use a from import unless the variable is intended to be a constant. from shared_stuff import a would create a new a variable initialized to whatever shared_stuff.a referred to at the time of the import, and this new a variable would not be affected by assignments to shared_stuff.a.


Or, in the rare case that you really do need it to be truly global everywhere, like a builtin, add it to the builtin module. The exact details differ between Python 2.x and 3.x. In 3.x, it works like this:

import builtins
import module1
builtins.a = 3
module1.f()

How to open a new tab using Selenium WebDriver

Do this:

driver.ExecuteScript("window.open('your URL', '_blank');");

set column width of a gridview in asp.net

This what worked for me. set HeaderStyle-Width="5%", in the footer set textbox width Width="15",also set the width of your gridview to 100%. following is the one of the column of my gridview.

    <asp:TemplateField   HeaderText = "sub" HeaderStyle-ForeColor="White" HeaderStyle-Width="5%">
<ItemTemplate>
    <asp:Label ID="sub" runat="server" Font-Size="small" Text='<%# Eval("sub")%>'></asp:Label>
</ItemTemplate> 
 <EditItemTemplate>
    <asp:TextBox ID="txt_sub" runat="server" Text='<%# Eval("sub")%>'></asp:TextBox>
</EditItemTemplate> 
<FooterTemplate>
    <asp:TextBox ID="txt_sub" runat="server" Width="15"></asp:TextBox>
</FooterTemplate>

SQL Server stored procedure creating temp table and inserting value

A SELECT INTO statement creates the table for you. There is no need for the CREATE TABLE statement before hand.

What is happening is that you create #ivmy_cash_temp1 in your CREATE statement, then the DB tries to create it for you when you do a SELECT INTO. This causes an error as it is trying to create a table that you have already created.

Either eliminate the CREATE TABLE statement or alter your query that fills it to use INSERT INTO SELECT format.

If you need a unique ID added to your new row then it's best to use SELECT INTO... since IDENTITY() only works with this syntax.

No restricted globals

Perhaps you could try passing location into the component as a prop. Below I use ...otherProps. This is the spread operator, and is valid but unneccessary if you passed in your props explicitly it's just there as a place holder for demonstration purposes. Also, research destructuring to understand where ({ location }) came from.

import React from 'react';
import withRouter from 'react-router-dom';

const MyComponent = ({ location, ...otherProps }) => (whatever you want to render)


export withRouter(MyComponent);

OkHttp Post Body as JSON

In okhttp v4.* I got it working that way


// import the extensions!
import okhttp3.MediaType.Companion.toMediaType
import okhttp3.RequestBody.Companion.toRequestBody

// ...

json : String = "..."

val JSON : MediaType = "application/json; charset=utf-8".toMediaType()
val jsonBody: RequestBody = json.toRequestBody(JSON)

// go on with Request.Builder() etc

How to change the cursor into a hand when a user hovers over a list item?

I think it would be smart to only show the hand/pointer cursor when JavaScript is available. So people will not have the feeling they can click on something that is not clickable.

To achieve that you could use the JavaScript libary jQuery to add the CSS to the element like so

$("li").css({"cursor":"pointer"});

Or chain it directly to the click handler.

Or when modernizer in combination with <html class="no-js"> is used, the CSS would look like this:

.js li { cursor: pointer; }

How to have the cp command create any necessary folders for copying a file to a destination

I didn't know you could do that with cp.

You can do it with mkdir ..

mkdir -p /var/path/to/your/dir

EDIT See lhunath's answer for incorporating cp.

Open an html page in default browser with VBA?

You can even say:

FollowHyperlink "www.google.com"

If you get Automation Error then use http://:

ThisWorkbook.FollowHyperlink("http://www.google.com")

Using Python to execute a command on every file in a folder

The new recommend way in Python3 is to use pathlib:

from pathlib import Path

mydir = Path("path/to/my/dir")
for file in mydir.glob('*.mp4'):
    print(file.name)
    # do your stuff

Instead of *.mp4 you can use any filter, even a recursive one like **/*.mp4. If you want to use more than one extension, you can simply iterate all with * or **/* (recursive) and check every file's extension with file.name.endswith(('.mp4', '.webp', '.avi', '.wmv', '.mov'))

How do you find the row count for all your tables in Postgres

The hacky, practical answer for people trying to evaluate which Heroku plan they need and can't wait for heroku's slow row counter to refresh:

Basically you want to run \dt in psql, copy the results to your favorite text editor (it will look like this:

 public | auth_group                     | table | axrsosvelhutvw
 public | auth_group_permissions         | table | axrsosvelhutvw
 public | auth_permission                | table | axrsosvelhutvw
 public | auth_user                      | table | axrsosvelhutvw
 public | auth_user_groups               | table | axrsosvelhutvw
 public | auth_user_user_permissions     | table | axrsosvelhutvw
 public | background_task                | table | axrsosvelhutvw
 public | django_admin_log               | table | axrsosvelhutvw
 public | django_content_type            | table | axrsosvelhutvw
 public | django_migrations              | table | axrsosvelhutvw
 public | django_session                 | table | axrsosvelhutvw
 public | exercises_assignment           | table | axrsosvelhutvw

), then run a regex search and replace like this:

^[^|]*\|\s+([^|]*?)\s+\| table \|.*$

to:

select '\1', count(*) from \1 union/g

which will yield you something very similar to this:

select 'auth_group', count(*) from auth_group union
select 'auth_group_permissions', count(*) from auth_group_permissions union
select 'auth_permission', count(*) from auth_permission union
select 'auth_user', count(*) from auth_user union
select 'auth_user_groups', count(*) from auth_user_groups union
select 'auth_user_user_permissions', count(*) from auth_user_user_permissions union
select 'background_task', count(*) from background_task union
select 'django_admin_log', count(*) from django_admin_log union
select 'django_content_type', count(*) from django_content_type union
select 'django_migrations', count(*) from django_migrations union
select 'django_session', count(*) from django_session
;

(You'll need to remove the last union and add the semicolon at the end manually)

Run it in psql and you're done.

            ?column?            | count
--------------------------------+-------
 auth_group_permissions         |     0
 auth_user_user_permissions     |     0
 django_session                 |  1306
 django_content_type            |    17
 auth_user_groups               |   162
 django_admin_log               |  9106
 django_migrations              |    19
[..]

Two-dimensional array in Swift

Define mutable array

// 2 dimensional array of arrays of Ints 
var arr = [[Int]]() 

OR:

// 2 dimensional array of arrays of Ints 
var arr: [[Int]] = [] 

OR if you need an array of predefined size (as mentioned by @0x7fffffff in comments):

// 2 dimensional array of arrays of Ints set to 0. Arrays size is 10x5
var arr = Array(count: 3, repeatedValue: Array(count: 2, repeatedValue: 0))

// ...and for Swift 3+:
var arr = Array(repeating: Array(repeating: 0, count: 2), count: 3)

Change element at position

arr[0][1] = 18

OR

let myVar = 18
arr[0][1] = myVar

Change sub array

arr[1] = [123, 456, 789] 

OR

arr[0] += 234

OR

arr[0] += [345, 678]

If you had 3x2 array of 0(zeros) before these changes, now you have:

[
  [0, 0, 234, 345, 678], // 5 elements!
  [123, 456, 789],
  [0, 0]
]

So be aware that sub arrays are mutable and you can redefine initial array that represented matrix.

Examine size/bounds before access

let a = 0
let b = 1

if arr.count > a && arr[a].count > b {
    println(arr[a][b])
}

Remarks: Same markup rules for 3 and N dimensional arrays.

AngularJS $watch window resize inside directive

You can listen resize event and fire where some dimension change

directive

(function() {
'use strict';

    angular
    .module('myApp.directives')
    .directive('resize', ['$window', function ($window) {
        return {
            link: link,
            restrict: 'A'
        };

        function link(scope, element, attrs){
            scope.width = $window.innerWidth;
            function onResize(){
                // uncomment for only fire when $window.innerWidth change   
                // if (scope.width !== $window.innerWidth)
                {
                    scope.width = $window.innerWidth;
                    scope.$digest();
                }
            };

            function cleanUp() {
                angular.element($window).off('resize', onResize);
            }

            angular.element($window).on('resize', onResize);
            scope.$on('$destroy', cleanUp);
        }
    }]);
})();

In html

<div class="row" resize> ,
    <div class="col-sm-2 col-xs-6" ng-repeat="v in tag.vod"> 
        <h4 ng-bind="::v.known_as"></h4>
    </div> 
</div> 

Controller :

$scope.$watch('width', function(old, newv){
     console.log(old, newv);
 })

Difference between <? super T> and <? extends T> in Java

You can go through all the answers above to understand why the .add() is restricted to '<?>', '<? extends>', and partly to '<? super>'.

But here's the conclusion of it all if you want to remember it, and dont want to go exploring the answer every time:

List<? extends A> means this will accept any List of A and subclass of A. But you cannot add anything to this list. Not even objects of type A.

List<? super A> means this will accept any list of A and superclass of A. You can add objects of type A and its subclasses.

Why does .json() return a promise?

Also, what helped me understand this particular scenario that you described is the Promise API documentation, specifically where it explains how the promised returned by the then method will be resolved differently depending on what the handler fn returns:

if the handler function:

  • returns a value, the promise returned by then gets resolved with the returned value as its value;
  • throws an error, the promise returned by then gets rejected with the thrown error as its value;
  • returns an already resolved promise, the promise returned by then gets resolved with that promise's value as its value;
  • returns an already rejected promise, the promise returned by then gets rejected with that promise's value as its value.
  • returns another pending promise object, the resolution/rejection of the promise returned by then will be subsequent to the resolution/rejection of the promise returned by the handler. Also, the value of the promise returned by then will be the same as the value of the promise returned by the handler.

Moving matplotlib legend outside of the axis makes it cutoff by the figure box

Sorry EMS, but I actually just got another response from the matplotlib mailling list (Thanks goes out to Benjamin Root).

The code I am looking for is adjusting the savefig call to:

fig.savefig('samplefigure', bbox_extra_artists=(lgd,), bbox_inches='tight')
#Note that the bbox_extra_artists must be an iterable

This is apparently similar to calling tight_layout, but instead you allow savefig to consider extra artists in the calculation. This did in fact resize the figure box as desired.

import matplotlib.pyplot as plt
import numpy as np

plt.gcf().clear()
x = np.arange(-2*np.pi, 2*np.pi, 0.1)
fig = plt.figure(1)
ax = fig.add_subplot(111)
ax.plot(x, np.sin(x), label='Sine')
ax.plot(x, np.cos(x), label='Cosine')
ax.plot(x, np.arctan(x), label='Inverse tan')
handles, labels = ax.get_legend_handles_labels()
lgd = ax.legend(handles, labels, loc='upper center', bbox_to_anchor=(0.5,-0.1))
text = ax.text(-0.2,1.05, "Aribitrary text", transform=ax.transAxes)
ax.set_title("Trigonometry")
ax.grid('on')
fig.savefig('samplefigure', bbox_extra_artists=(lgd,text), bbox_inches='tight')

This produces:

[edit] The intent of this question was to completely avoid the use of arbitrary coordinate placements of arbitrary text as was the traditional solution to these problems. Despite this, numerous edits recently have insisted on putting these in, often in ways that led to the code raising an error. I have now fixed the issues and tidied the arbitrary text to show how these are also considered within the bbox_extra_artists algorithm.

How do I force my .NET application to run as administrator?

Another way of doing this, in code only, is to detect if the process is running as admin like in the answer by @NG.. And then open the application again and close the current one.

I use this code when an application only needs admin privileges when run under certain conditions, such as when installing itself as a service. So it doesn't need to run as admin all the time like the other answers force it too.

Note in the below code NeedsToRunAsAdmin is a method that detects if under current conditions admin privileges are required. If this returns false the code will not elevate itself. This is a major advantage of this approach over the others.

Although this code has the advantages stated above, it does need to re-launch itself as a new process which isn't always what you want.

private static void Main(string[] args)
{
    if (NeedsToRunAsAdmin() && !IsRunAsAdmin())
    {
        ProcessStartInfo proc = new ProcessStartInfo();
        proc.UseShellExecute = true;
        proc.WorkingDirectory = Environment.CurrentDirectory;
        proc.FileName = Assembly.GetEntryAssembly().CodeBase;

        foreach (string arg in args)
        {
            proc.Arguments += String.Format("\"{0}\" ", arg);
        }

        proc.Verb = "runas";

        try
        {
            Process.Start(proc);
        }
        catch
        {
            Console.WriteLine("This application requires elevated credentials in order to operate correctly!");
        }
    }
    else
    {
        //Normal program logic...
    }
}

private static bool IsRunAsAdmin()
{
    WindowsIdentity id = WindowsIdentity.GetCurrent();
    WindowsPrincipal principal = new WindowsPrincipal(id);

    return principal.IsInRole(WindowsBuiltInRole.Administrator);
}

What is the difference between JAX-RS and JAX-WS?

i have been working on Apachi Axis1.1 and Axis2.0 and JAX-WS but i would suggest you must JAX-WS because it allow you make wsdl in any format , i was making operation as GetInquiry() in Apache Axis2 it did not allow me to Start Operation name in Upper Case , so i find it not good , so i would suggest you must use JAX-WS

How do I make JavaScript beep?

As we read in this answer, HTML5 will solve this for you if you're open to that route. HTML5 audio is supported in all modern browsers.

Here's a copy of the example:

var snd = new Audio("file.wav"); // buffers automatically when created
snd.play();

Stop executing further code in Java

You can just use return to end the method's execution

How to avoid scientific notation for large numbers in JavaScript?

You can use from-exponential module. It is lightweight and fully tested.

import fromExponential from 'from-exponential';

fromExponential(1.123e-10); // => '0.0000000001123'

"Use the new keyword if hiding was intended" warning

The parent function needs the virtual keyword, and the child function needs the override keyword in front of the function definition.

What is the difference between dict.items() and dict.iteritems() in Python2?

If you have

dict = {key1:value1, key2:value2, key3:value3,...}

In Python 2, dict.items() copies each tuples and returns the list of tuples in dictionary i.e. [(key1,value1), (key2,value2), ...]. Implications are that the whole dictionary is copied to new list containing tuples

dict = {i: i * 2 for i in xrange(10000000)}  
# Slow and memory hungry.
for key, value in dict.items():
    print(key,":",value)

dict.iteritems() returns the dictionary item iterator. The value of the item returned is also the same i.e. (key1,value1), (key2,value2), ..., but this is not a list. This is only dictionary item iterator object. That means less memory usage (50% less).

  • Lists as mutable snapshots: d.items() -> list(d.items())
  • Iterator objects: d.iteritems() -> iter(d.items())

The tuples are the same. You compared tuples in each so you get same.

dict = {i: i * 2 for i in xrange(10000000)}  
# More memory efficient.
for key, value in dict.iteritems():
    print(key,":",value)

In Python 3, dict.items() returns iterator object. dict.iteritems() is removed so there is no more issue.

Necessary to add link tag for favicon.ico?

<link rel="icon" type="image/x-icon" href="http://example.com/favicon.ico" />
<link rel="icon" type="image/png" href="http://example.com/favicon.png" />
<link rel="icon" type="image/gif" href="http://example.com/favicon.gif" />
<link rel="icon" type="image/jpeg" href="http://example.com/favicon.jpeg" />
<link rel="icon" type="image/webp" href="http://example.com/favicon.webp" />

It all depends on which format of image you like to use!
if you have an icon of your website, it will be much better for UX!

demo

show logo in the browser tab

enter image description here

Uncaught Error: SECURITY_ERR: DOM Exception 18 when I try to set a cookie

I was been getting that error in mobile safari when using ASP.NET MVC to return a FileResult with the overload that returns a file with a different file name than the original. So,

return File(returnFilePath, contentType, fileName);

would give the error in mobile safari, where as

return File(returnFilePath, contentType);

would not.

I don't even remember why I thought what I was doing was a good idea. Trying to be clever I guess.

Binary numbers in Python

'''
I expect the intent behind this assignment was to work in binary string format.
This is absolutely doable.
'''

def compare(bin1, bin2):
    return bin1.lstrip('0') == bin2.lstrip('0')

def add(bin1, bin2):
    result = ''
    blen = max((len(bin1), len(bin2))) + 1
    bin1, bin2 = bin1.zfill(blen), bin2.zfill(blen)
    carry_s = '0'
    for b1, b2 in list(zip(bin1, bin2))[::-1]:
        count = (carry_s, b1, b2).count('1')
        carry_s = '1' if count >= 2 else '0'
        result += '1' if count % 2 else '0'
    return result[::-1]

if __name__ == '__main__':
    print(add('101', '100'))

I leave the subtraction func as an exercise for the reader.

How do I calculate a point on a circle’s circumference?

Implemented in JavaScript (ES6):

/**
    * Calculate x and y in circle's circumference
    * @param {Object} input - The input parameters
    * @param {number} input.radius - The circle's radius
    * @param {number} input.angle - The angle in degrees
    * @param {number} input.cx - The circle's origin x
    * @param {number} input.cy - The circle's origin y
    * @returns {Array[number,number]} The calculated x and y
*/
function pointsOnCircle({ radius, angle, cx, cy }){

    angle = angle * ( Math.PI / 180 ); // Convert from Degrees to Radians
    const x = cx + radius * Math.sin(angle);
    const y = cy + radius * Math.cos(angle);
    return [ x, y ];

}

Usage:

const [ x, y ] = pointsOnCircle({ radius: 100, angle: 180, cx: 150, cy: 150 });
console.log( x, y );

Codepen

_x000D_
_x000D_
/**
 * Calculate x and y in circle's circumference
 * @param {Object} input - The input parameters
 * @param {number} input.radius - The circle's radius
 * @param {number} input.angle - The angle in degrees
 * @param {number} input.cx - The circle's origin x
 * @param {number} input.cy - The circle's origin y
 * @returns {Array[number,number]} The calculated x and y
 */
function pointsOnCircle({ radius, angle, cx, cy }){
  angle = angle * ( Math.PI / 180 ); // Convert from Degrees to Radians
  const x = cx + radius * Math.sin(angle);
  const y = cy + radius * Math.cos(angle);
  return [ x, y ];
}

const canvas = document.querySelector("canvas");
const ctx = canvas.getContext("2d");

function draw( x, y ){

  ctx.clearRect( 0, 0, canvas.width, canvas.height );
  ctx.beginPath();
  ctx.strokeStyle = "orange";
  ctx.arc( 100, 100, 80, 0, 2 * Math.PI);
  ctx.lineWidth = 3;
  ctx.stroke();
  ctx.closePath();

  ctx.beginPath();
  ctx.fillStyle = "indigo";
  ctx.arc( x, y, 6, 0, 2 * Math.PI);
  ctx.fill();
  ctx.closePath();
  
}

let angle = 0;  // In degrees
setInterval(function(){

  const [ x, y ] = pointsOnCircle({ radius: 80, angle: angle++, cx: 100, cy: 100 });
  console.log( x, y );
  draw( x, y );
  document.querySelector("#degrees").innerHTML = angle + "&deg;";
  document.querySelector("#points").textContent = x.toFixed() + "," + y.toFixed();

}, 100 );
_x000D_
<p>Degrees: <span id="degrees">0</span></p>
<p>Points on Circle (x,y): <span id="points">0,0</span></p>
<canvas width="200" height="200" style="border: 1px solid"></canvas>
_x000D_
_x000D_
_x000D_

Differences between strong and weak in Objective-C

A strong reference (which you will use in most cases) means that you want to "own" the object you are referencing with this property/variable. The compiler will take care that any object that you assign to this property will not be destroyed as long as you point to it with a strong reference. Only once you set the property to nil will the object get destroyed (unless one or more other objects also hold a strong reference to it).

In contrast, with a weak reference you signify that you don't want to have control over the object's lifetime. The object you are referencing weakly only lives on because at least one other object holds a strong reference to it. Once that is no longer the case, the object gets destroyed and your weak property will automatically get set to nil. The most frequent use cases of weak references in iOS are:

  1. delegate properties, which are often referenced weakly to avoid retain cycles, and

  2. subviews/controls of a view controller's main view because those views are already strongly held by the main view.

atomic vs. nonatomic refers to the thread safety of the getter and setter methods that the compiler synthesizes for the property. atomic (the default) tells the compiler to make the accessor methods thread-safe (by adding a lock before an ivar is accessed) and nonatomic does the opposite. The advantage of nonatomic is slightly higher performance. On iOS, Apple uses nonatomic for almost all their properties so the general advice is for you to do the same.

Kotlin: How to get and set a text to TextView in Android using Kotlin?

Yes its late - but may help someone on reference

xml with EditText, Button and TextView

onClick on Button will update the value from EditText to TextView

        <EditText
            android:id="@+id/et_id"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>

        <Button
            android:id="@+id/btn_submit_id"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>

        <TextView
            android:id="@+id/txt_id"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>

Look at the code do the action in your class

Don't need to initialize the id's of components like in Java. You can do it by their xml Id's

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_sample)

        btn_submit_id.setOnClickListener {
            txt_id.setText(et_id.text);
        }
    }

also you can set value in TextView like,

textview.text = "your value"

How to downgrade to older version of Gradle

I did following steps to downgrade Gradle back to the original version:

  • I deleted content of '.gradle/caches' folder in user home directory (windows).
  • I deleted content of '.gradle' folder in my project root.
  • I checked that Gradle version is properly set in 'Project' option of 'Project Structure' in Android Studio.
  • I selected 'Use default gradle wrapper' option in 'Settings' in Android Studio, just search for gradle key word to find it.

Probably last step is enough as in my case the path to the new Gradle distribution was hardcoded there under 'Gradle home' option.

Use of Greater Than Symbol in XML

Use &gt; and &lt; for 'greater-than' and 'less-than' respectively

How to disable/enable a button with a checkbox if checked

You will have to use javascript, or the JQuery framework to do that. her is an example using Jquery

   $('#toggle').click(function () {
        //check if checkbox is checked
        if ($(this).is(':checked')) {

            $('#sendNewSms').removeAttr('disabled'); //enable input

        } else {
            $('#sendNewSms').attr('disabled', true); //disable input
        }
    });

DEMO: http://jsfiddle.net/T6hvz/

Append text with .bat

Any line starting with a "REM" is treated as a comment, nothing is executed including the redirection.

Also, the %date% variable may contain "/" characters which are treated as path separator characters, leading to the system being unable to create the desired log file.

How to check if a double value has no decimal part

either ceil and floor should give the same out out put

Math.ceil(x.y) == Math.floor(x.y)

or simply check for equality with double value

x.y == Math.ceil(x.y)
x.y == Math.floor(x.y)

or

Math.round(x.y) == x.y

Could not autowire field:RestTemplate in Spring boot application

Depending on what technologies you're using and what versions will influence how you define a RestTemplate in your @Configuration class.

Spring >= 4 without Spring Boot

Simply define an @Bean:

@Bean
public RestTemplate restTemplate() {
    return new RestTemplate();
}

Spring Boot <= 1.3

No need to define one, Spring Boot automatically defines one for you.

Spring Boot >= 1.4

Spring Boot no longer automatically defines a RestTemplate but instead defines a RestTemplateBuilder allowing you more control over the RestTemplate that gets created. You can inject the RestTemplateBuilder as an argument in your @Bean method to create a RestTemplate:

@Bean
public RestTemplate restTemplate(RestTemplateBuilder builder) {
   // Do any additional configuration here
   return builder.build();
}

Using it in your class

@Autowired
private RestTemplate restTemplate;

Reference

How do I get this javascript to run every second?

Use setInterval() to run a piece of code every x milliseconds.

You can wrap the code you want to run every second in a function called runFunction.

So it would be:

var t=setInterval(runFunction,1000);

And to stop it, you can run:

clearInterval(t);

Opposite of append in jquery

Opposite up is children(), but opposite in position is prepend(). Here a very good tutorial.

"Comparison method violates its general contract!"

In my case, it was an infinite sort. That is, at first the line moved up according to the condition, and then the same line moved down to the same place. I added one more condition at the end that unambiguously established the order of the lines.

Android Button setOnClickListener Design

Implement Activity with View.OnClickListener like below.

public class MyActivity extends AppCompatActivity implements View.OnClickListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_scan_options);

        Button button = findViewById(R.id.button);
        Button button2 = findViewById(R.id.button2);

        button.setOnClickListener(this);
        button2.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {

        int id = view.getId();

        switch (id) {

            case R.id.button:

                  // Write your code here first button

                break;

             case R.id.button2:

                  // Write your code here for second button

                break;

        }

    }

}

How to create a trie in Python

This version is using recursion

import pprint
from collections import deque

pp = pprint.PrettyPrinter(indent=4)

inp = raw_input("Enter a sentence to show as trie\n")
words = inp.split(" ")
trie = {}


def trie_recursion(trie_ds, word):
    try:
        letter = word.popleft()
        out = trie_recursion(trie_ds.get(letter, {}), word)
    except IndexError:
        # End of the word
        return {}

    # Dont update if letter already present
    if not trie_ds.has_key(letter):
        trie_ds[letter] = out

    return trie_ds

for word in words:
    # Go through each word
    trie = trie_recursion(trie, deque(word))

pprint.pprint(trie)

Output:

Coool <algos>  python trie.py
Enter a sentence to show as trie
foo bar baz fun
{
  'b': {
    'a': {
      'r': {},
      'z': {}
    }
  },
  'f': {
    'o': {
      'o': {}
    },
    'u': {
      'n': {}
    }
  }
}

Remove last character of a StringBuilder?

Another simple solution is:

sb.setLength(sb.length() - 1);

A more complicated solution:

The above solution assumes that sb.length() > 0 ... i.e. there is a "last character" to remove. If you can't make that assumption, and/or you can't deal with the exception that would ensue if the assumption is incorrect, then check the StringBuilder's length first; e.g.

// Readable version
if (sb.length() > 0) {
   sb.setLength(sb.length() - 1);
}

or

// Concise but harder-to-read version of the above.
sb.setLength(Math.max(sb.length() - 1, 0));

Initialize a long in Java

  1. You should add L: long i = 12345678910L;.
  2. Yes.

BTW: it doesn't have to be an upper case L, but lower case is confused with 1 many times :).

Import file size limit in PHPMyAdmin

I had the same problem. My Solution: go to /etc/phpmyadmin and edit apache.conf in the <Directory>[...]</Directory> section you can add

php_value upload_max_filesize 10M
php_value post_max_size 10M

Solved the problem for me!

Using PowerShell credentials without being prompted for a password

why dont you try something very simple?

use psexec with command 'shutdown /r /f /t 0' and a PC list from CMD.

Is there a limit on how much JSON can hold?

Surely everyone's missed a trick here. The current file size limit of a json file is 18,446,744,073,709,551,616 characters or if you prefer bytes, or even 2^64 bytes if you're looking at 64 bit infrastructures at least.

For all intents, and purposes we can assume it's unlimited as you'll probably have a hard time hitting this issue...

How to query values from xml nodes?

Try this:

SELECT RawXML.value('(/GrobXmlFile//Grob//ReportHeader//OrganizationReportReferenceIdentifier/node())[1]','varchar(50)') AS ReportIdentifierNumber,
       RawXML.value('(/GrobXmlFile//Grob//ReportHeader//OrganizationNumber/node())[1]','int') AS OrginazationNumber
FROM Batches

Get first letter of a string from column

Cast the dtype of the col to str and you can perform vectorised slicing calling str:

In [29]:
df['new_col'] = df['First'].astype(str).str[0]
df

Out[29]:
   First  Second new_col
0    123     234       1
1     22    4353       2
2     32     355       3
3    453     453       4
4     45     345       4
5    453     453       4
6     56      56       5

if you need to you can cast the dtype back again calling astype(int) on the column

What is the difference between HTTP and REST?

Not quite...

http://en.wikipedia.org/wiki/Representational_State_Transfer

REST was initially described in the context of HTTP, but is not limited to that protocol. RESTful architectures can be based on other Application Layer protocols if they already provide a rich and uniform vocabulary for applications based on the transfer of meaningful representational state. RESTful applications maximise the use of the pre-existing, well-defined interface and other built-in capabilities provided by the chosen network protocol, and minimise the addition of new application-specific features on top of it.

http://www.looselycoupled.com/glossary/SOAP

(Simple Object Access Protocol) The standard for web services messages. Based on XML, SOAP defines an envelope format and various rules for describing its contents. Seen (with WSDL and UDDI) as one of the three foundation standards of web services, it is the preferred protocol for exchanging web services, but by no means the only one; proponents of REST say that it adds unnecessary complexity.

How to create checkbox inside dropdown?

This can't be done in just HTML (with form elements into option elements).

Or you can just use a standard select multiple field.

<select multiple>
  <option value="a">a</option>
  <option value="b">b</option>
  <option value="c">c</option>
</select>

unsigned int vs. size_t

If my compiler is set to 32 bit, size_t is nothing other than a typedef for unsigned int. If my compiler is set to 64 bit, size_t is nothing other than a typedef for unsigned long long.

How do I scroll to an element using JavaScript?

your question and the answers looks different. I don't know if I am mistaken, but for those who googles and reach here my answer would be the following:

  1. My answer on stackoverflow
  2. A similar question

My Answer explained:

here is a simple javascript for that

call this when you need to scroll the screen to an element which has id="yourSpecificElementId"

window.scroll(0,findPos(document.getElementById("yourSpecificElementId")));

ie. for the above question, if the intention is to scroll the screen to the div with id 'divFirst'

the code would be: window.scroll(0,findPos(document.getElementById("divFirst")));

and you need this function for the working:

//Finds y value of given object
function findPos(obj) {
    var curtop = 0;
    if (obj.offsetParent) {
        do {
            curtop += obj.offsetTop;
        } while (obj = obj.offsetParent);
    return [curtop];
    }
}

the screen will be scrolled to your specific element.

check for null date in CASE statement, where have I gone wrong?

Try:

select
     id,
     StartDate,
CASE WHEN StartDate IS NULL
    THEN 'Awaiting'
    ELSE 'Approved' END AS StartDateStatus
FROM myTable

You code would have been doing a When StartDate = NULL, I think.


NULL is never equal to NULL (as NULL is the absence of a value). NULL is also never not equal to NULL. The syntax noted above is ANSI SQL standard and the converse would be StartDate IS NOT NULL.

You can run the following:

SELECT CASE WHEN (NULL = NULL) THEN 1 ELSE 0 END AS EqualityCheck,
CASE WHEN (NULL <> NULL) THEN 1 ELSE 0 END AS InEqualityCheck,
CASE WHEN (NULL IS NULL) THEN 1 ELSE 0 END AS NullComparison

And this returns:

EqualityCheck = 0
InEqualityCheck = 0
NullComparison = 1

For completeness, in SQL Server you can:

SET ANSI_NULLS OFF;

Which would result in your equals comparisons working differently:

SET ANSI_NULLS OFF

SELECT CASE WHEN (NULL = NULL) THEN 1 ELSE 0 END AS EqualityCheck,
CASE WHEN (NULL <> NULL) THEN 1 ELSE 0 END AS InEqualityCheck,
CASE WHEN (NULL IS NULL) THEN 1 ELSE 0 END AS NullComparison

Which returns:

EqualityCheck = 1
InEqualityCheck = 0
NullComparison = 1

But I would highly recommend against doing this. People subsequently maintaining your code might be compelled to hunt you down and hurt you...

Also, it will no longer work in upcoming versions of SQL server:

https://msdn.microsoft.com/en-GB/library/ms188048.aspx

Limit Decimal Places in Android EditText

@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
    String numero = total.getText().toString();
    int dec = numero.indexOf(".");
    int longitud = numero.length();
    if (dec+3 == longitud && dec != -1) { //3 number decimal + 1
        log.i("ento","si");
        numero = numero.substring(0,dec+3);
        if (contador == 0) {
            contador = 1;
            total.setText(numero);
            total.setSelection(numero.length());
        } else {
            contador = 0;
        }
    }
}

AWS S3 CLI - Could not connect to the endpoint URL

  1. Check the .aws directory under home directory. Windows: C:\Users<home-name>.aws Linux: ~/.aws

  2. Under this directory, you will find the config as well as credentials file. It will have the information from the aws configure that you may have run before. IF not, then

  3. Run aws configure Enter the access key - secret key - enter secret key region - (ap-southeast-1 or us-east-1 or any other regions) format - (json or leave it blank, it will pick up default values you may simply hit enter)

  4. From the Step 2, you should see the config file, open it, it should have the region. Please ensure there is region specified.

  5. You may now run the following command to list the buckets aws s3 ls It should work fine.

Count the number of all words in a string

With stringr package, one can also write a simple script that could traverse a vector of strings for example through a for loop.

Let's say

df$text

contains a vector of strings that we are interested in analysing. First, we add additional columns to the existing dataframe df as below:

df$strings    = as.integer(NA)
df$characters = as.integer(NA)

Then we run a for-loop over the vector of strings as below:

for (i in 1:nrow(df)) 
{
   df$strings[i]    = str_count(df$text[i], '\\S+') # counts the strings
   df$characters[i] = str_count(df$text[i])         # counts the characters & spaces
}

The resulting columns: strings and character will contain the counts of words and characters and this will be achieved in one-go for a vector of strings.

How to use Console.WriteLine in ASP.NET (C#) during debug?

Trace.Write("Error Message") and Trace.Warn("Error Message") are the methods to use in web, need to decorate the page header trace=true and in config file to hide the error message text to go to end-user and so as to stay in iis itself for programmer debug.

Multi-line string with extra space (preserved indentation)

in a bash script the following works:

#!/bin/sh

text="this is line one\nthis is line two\nthis is line three"
echo -e $text > filename

alternatively:

text="this is line one
this is line two
this is line three"
echo "$text" > filename

cat filename gives:

this is line one
this is line two
this is line three

Lost httpd.conf file located apache

See http://wiki.apache.org/httpd/DistrosDefaultLayout for discussion of where you might find Apache httpd configuration files on various platforms, since this can vary from release to release and platform to platform. The most common answer, however, is either /etc/apache/conf or /etc/httpd/conf

Generically, you can determine the answer by running the command:

httpd -V

(That's a capital V). Or, on systems where httpd is renamed, perhaps apache2ctl -V

This will return various details about how httpd is built and configured, including the default location of the main configuration file.

One of the lines of output should look like:

-D SERVER_CONFIG_FILE="conf/httpd.conf"

which, combined with the line:

-D HTTPD_ROOT="/etc/httpd"

will give you a full path to the default location of the configuration file

How to detect Ctrl+V, Ctrl+C using JavaScript?

A hook that allows for overriding copy events, could be used for doing the same with paste events. The input element cannot be display: none; or visibility: hidden; sadly

export const useOverrideCopy = () => {
  const [copyListenerEl, setCopyListenerEl] = React.useState(
    null as HTMLInputElement | null
  )
  const [, setCopyHandler] = React.useState<(e: ClipboardEvent) => void | null>(
    () => () => {}
  )
  // appends a input element to the DOM, that will be focused.
  // when using copy/paste etc, it will target focused elements
  React.useEffect(() => {
    const el = document.createElement("input")  
    // cannot focus a element that is not "visible" aka cannot use display: none or visibility: hidden
    el.style.width = "0"
    el.style.height = "0"
    el.style.opacity = "0"
    el.style.position = "fixed"
    el.style.top = "-20px"
    document.body.appendChild(el)
    setCopyListenerEl(el)
    return () => {
      document.body.removeChild(el)
    }
  }, [])
  // adds a event listener for copying, and removes the old one 
  const overrideCopy = (newOverrideAction: () => any) => {
    setCopyHandler((prevCopyHandler: (e: ClipboardEvent) => void) => {
      const copyHandler = (e: ClipboardEvent) => {
        e.preventDefault()
        newOverrideAction()
      }
      copyListenerEl?.removeEventListener("copy", prevCopyHandler)
      copyListenerEl?.addEventListener("copy", copyHandler)
      copyListenerEl?.focus() // when focused, all copy events will trigger listener above
      return copyHandler
    })
  }
  return { overrideCopy }
}

Used like this:

const customCopyEvent = () => {
    console.log("doing something")
} 
const { overrideCopy } = useOverrideCopy()
overrideCopy(customCopyEvent)

Every time you call overrideCopy it will refocus and call your custom event on copy.

Oracle - Best SELECT statement for getting the difference in minutes between two DateTime columns?

SELECT date1 - date2
  FROM some_table

returns a difference in days. Multiply by 24 to get a difference in hours and 24*60 to get minutes. So

SELECT (date1 - date2) * 24 * 60 difference_in_minutes
  FROM some_table

should be what you're looking for

How to redirect the output of an application in background to /dev/null

You use:

yourcommand  > /dev/null 2>&1

If it should run in the Background add an &

yourcommand > /dev/null 2>&1 &

>/dev/null 2>&1 means redirect stdout to /dev/null AND stderr to the place where stdout points at that time

If you want stderr to occur on console and only stdout going to /dev/null you can use:

yourcommand 2>&1 > /dev/null

In this case stderr is redirected to stdout (e.g. your console) and afterwards the original stdout is redirected to /dev/null

If the program should not terminate you can use:

nohup yourcommand &

Without any parameter all output lands in nohup.out

jQuery, simple polling example

From ES6,

var co = require('co');
var $ = require('jQuery');

// because jquery doesn't support Promises/A+ spec
function ajax(opts) {
  return new Promise(function(resolve, reject) {
    $.extend(opts, {
      success: resolve,
      error: reject
    });
    $.ajax(opts);
  }
}

var poll = function() {
  co(function *() {
    return yield ajax({
      url: '/my-api',
      type: 'json',
      method: 'post'
    });
  }).then(function(response) {
    console.log(response);
  }).catch(function(err) {
    console.log(err);
  });
};

setInterval(poll, 5000);
  • Doesn't use recursion (function stack is not affected).
  • Doesn't suffer where setTimeout-recursion needs to be tail-call optimized.

Passing event and argument to v-on in Vue.js

Depending on what arguments you need to pass, especially for custom event handlers, you can do something like this:

<div @customEvent='(arg1) => myCallback(arg1, arg2)'>Hello!</div>

assign headers based on existing row in dataframe in R

The cleanest way is use a function of janitor package that is built for exactly this purpose.

janitor::row_to_names(DF,1)

If you want to use any other row than the first one, pass it in the second parameter.

In which case do you use the JPA @JoinTable annotation?

@ManyToMany associations

Most often, you will need to use @JoinTable annotation to specify the mapping of a many-to-many table relationship:

  • the name of the link table and
  • the two Foreign Key columns

So, assuming you have the following database tables:

Many-to-many table relationship

In the Post entity, you would map this relationship, like this:

@ManyToMany(cascade = {
    CascadeType.PERSIST,
    CascadeType.MERGE
})
@JoinTable(
    name = "post_tag",
    joinColumns = @JoinColumn(name = "post_id"),
    inverseJoinColumns = @JoinColumn(name = "tag_id")
)
private List<Tag> tags = new ArrayList<>();

The @JoinTable annotation is used to specify the table name via the name attribute, as well as the Foreign Key column that references the post table (e.g., joinColumns) and the Foreign Key column in the post_tag link table that references the Tag entity via the inverseJoinColumns attribute.

Notice that the cascade attribute of the @ManyToMany annotation is set to PERSIST and MERGE only because cascading REMOVE is a bad idea since we the DELETE statement will be issued for the other parent record, tag in our case, not to the post_tag record.

Unidirectional @OneToMany associations

The unidirectional @OneToMany associations, that lack a @JoinColumn mapping, behave like many-to-many table relationships, rather than one-to-many.

So, assuming you have the following entity mappings:

@Entity(name = "Post")
@Table(name = "post")
public class Post {
 
    @Id
    @GeneratedValue
    private Long id;
 
    private String title;
 
    @OneToMany(
        cascade = CascadeType.ALL,
        orphanRemoval = true
    )
    private List<PostComment> comments = new ArrayList<>();
 
    //Constructors, getters and setters removed for brevity
}
 
@Entity(name = "PostComment")
@Table(name = "post_comment")
public class PostComment {
 
    @Id
    @GeneratedValue
    private Long id;
 
    private String review;
 
    //Constructors, getters and setters removed for brevity
}

Hibernate will assume the following database schema for the above entity mapping:

Unidirectional @OneToMany JPA association database tables

As already explained, the unidirectional @OneToMany JPA mapping behaves like a many-to-many association.

To customize the link table, you can also use the @JoinTable annotation:

@OneToMany(
    cascade = CascadeType.ALL,
    orphanRemoval = true
)
@JoinTable(
    name = "post_comment_ref",
    joinColumns = @JoinColumn(name = "post_id"),
    inverseJoinColumns = @JoinColumn(name = "post_comment_id")
)
private List<PostComment> comments = new ArrayList<>();

And now, the link table is going to be called post_comment_ref and the Foreign Key columns will be post_id, for the post table, and post_comment_id, for the post_comment table.

Unidirectional @OneToMany associations are not efficient, so you are better off using bidirectional @OneToMany associations or just the @ManyToOne side.

Retrieving the COM class factory for component failed

You will also get this error when there are stale EXCEL.EXE processes in the system (Use Task Manager --> Processes tab to view these.)

Kill all those instances and the application would work normally.

How to find serial number of Android device?

Since no answer here mentions a perfect, fail-proof ID that is both PERSISTENT through system updates and exists in ALL devices (mainly due to the fact that there isn't an individual solution from Google), I decided to post a method that is the next best thing by combining two of the available identifiers, and a check to chose between them at run-time.

Before code, 3 facts:

  1. TelephonyManager.getDeviceId() (a.k.a.IMEI) will not work well or at all for non-GSM, 3G, LTE, etc. devices, but will always return a unique ID when related hardware is present, even when no SIM is inserted or even when no SIM slot exists (some OEM's have done this).

  2. Since Gingerbread (Android 2.3) android.os.Build.SERIAL must exist on any device that doesn't provide IMEI, i.e., doesn't have the aforementioned hardware present, as per Android policy.

  3. Due to fact (2.), at least one of these two unique identifiers will ALWAYS be present, and SERIAL can be present at the same time that IMEI is.

Note: Fact (1.) and (2.) are based on Google statements

SOLUTION

With the facts above, one can always have a unique identifier by checking if there is IMEI-bound hardware, and fall back to SERIAL when it isn't, as one cannot check if the existing SERIAL is valid. The following static class presents 2 methods for checking such presence and using either IMEI or SERIAL:

import java.lang.reflect.Method;

import android.content.Context;
import android.content.pm.PackageManager;
import android.os.Build;
import android.provider.Settings;
import android.telephony.TelephonyManager;
import android.util.Log;

public class IDManagement {

    public static String getCleartextID_SIMCHECK (Context mContext){
        String ret = "";

        TelephonyManager telMgr = (TelephonyManager) mContext.getSystemService(Context.TELEPHONY_SERVICE);

        if(isSIMAvailable(mContext,telMgr)){
            Log.i("DEVICE UNIQUE IDENTIFIER",telMgr.getDeviceId());
            return telMgr.getDeviceId();

        }
        else{
            Log.i("DEVICE UNIQUE IDENTIFIER", Settings.Secure.ANDROID_ID);

//          return Settings.Secure.ANDROID_ID;
            return android.os.Build.SERIAL;
        }
    }


    public static String getCleartextID_HARDCHECK (Context mContext){
        String ret = "";

        TelephonyManager telMgr = (TelephonyManager) mContext.getSystemService(Context.TELEPHONY_SERVICE);
        if(telMgr != null && hasTelephony(mContext)){           
            Log.i("DEVICE UNIQUE IDENTIFIER",telMgr.getDeviceId() + "");

            return telMgr.getDeviceId();    
        }
        else{
            Log.i("DEVICE UNIQUE IDENTIFIER", Settings.Secure.ANDROID_ID);

//          return Settings.Secure.ANDROID_ID;
            return android.os.Build.SERIAL;
        }
    }


    public static boolean isSIMAvailable(Context mContext, 
            TelephonyManager telMgr){

        int simState = telMgr.getSimState();

        switch (simState) {
        case TelephonyManager.SIM_STATE_ABSENT:
            return false;
        case TelephonyManager.SIM_STATE_NETWORK_LOCKED:
            return false;
        case TelephonyManager.SIM_STATE_PIN_REQUIRED:
            return false;
        case TelephonyManager.SIM_STATE_PUK_REQUIRED:
            return false;
        case TelephonyManager.SIM_STATE_READY:
            return true;
        case TelephonyManager.SIM_STATE_UNKNOWN:
            return false;
        default:
            return false;
        }
    }

    static public boolean hasTelephony(Context mContext)
    {
        TelephonyManager tm = (TelephonyManager) mContext.getSystemService(Context.TELEPHONY_SERVICE);
        if (tm == null)
            return false;

        //devices below are phones only
        if (Build.VERSION.SDK_INT < 5)
            return true;

        PackageManager pm = mContext.getPackageManager();

        if (pm == null)
            return false;

        boolean retval = false;
        try
        {
            Class<?> [] parameters = new Class[1];
            parameters[0] = String.class;
            Method method = pm.getClass().getMethod("hasSystemFeature", parameters);
            Object [] parm = new Object[1];
            parm[0] = "android.hardware.telephony";
            Object retValue = method.invoke(pm, parm);
            if (retValue instanceof Boolean)
                retval = ((Boolean) retValue).booleanValue();
            else
                retval = false;
        }
        catch (Exception e)
        {
            retval = false;
        }

        return retval;
    }


}

I would advice on using getCleartextID_HARDCHECK. If the reflection doesn't stick in your environment, use the getCleartextID_SIMCHECK method instead, but take in consideration it should be adapted to your specific SIM-presence needs.

P.S.: Do please note that OEM's have managed to bug out SERIAL against Google policy (multiple devices with same SERIAL), and Google as stated there is at least one known case in a big OEM (not disclosed and I don't know which brand it is either, I'm guessing Samsung).

Disclaimer: This answers the original question of getting a unique device ID, but the OP introduced ambiguity by stating he needs a unique ID for an APP. Even if for such scenarios Android_ID would be better, it WILL NOT WORK after, say, a Titanium Backup of an app through 2 different ROM installs (can even be the same ROM). My solution maintains persistence that is independent of a flash or factory reset, and will only fail when IMEI or SERIAL tampering occurs through hacks/hardware mods.

How to fix the session_register() deprecated issue?

Don't use it. The description says:

Register one or more global variables with the current session.

Two things that came to my mind:

  1. Using global variables is not good anyway, find a way to avoid them.
  2. You can still set variables with $_SESSION['var'] = "value".

See also the warnings from the manual:

If you want your script to work regardless of register_globals, you need to instead use the $_SESSION array as $_SESSION entries are automatically registered. If your script uses session_register(), it will not work in environments where the PHP directive register_globals is disabled.

This is pretty important, because the register_globals directive is set to False by default!

Further:

This registers a global variable. If you want to register a session variable from within a function, you need to make sure to make it global using the global keyword or the $GLOBALS[] array, or use the special session arrays as noted below.

and

If you are using $_SESSION (or $HTTP_SESSION_VARS), do not use session_register(), session_is_registered(), and session_unregister().

How to refer to Excel objects in Access VBA?

I dissent from both the answers. Don't create a reference at all, but use late binding:

  Dim objExcelApp As Object
  Dim wb As Object

  Sub Initialize()
    Set objExcelApp = CreateObject("Excel.Application")
  End Sub

  Sub ProcessDataWorkbook()
     Set wb = objExcelApp.Workbooks.Open("path to my workbook")
     Dim ws As Object
     Set ws = wb.Sheets(1)

     ws.Cells(1, 1).Value = "Hello"
     ws.Cells(1, 2).Value = "World"

     'Close the workbook
     wb.Close
     Set wb = Nothing
  End Sub

You will note that the only difference in the code above is that the variables are all declared as objects and you instantiate the Excel instance with CreateObject().

This code will run no matter what version of Excel is installed, while using a reference can easily cause your code to break if there's a different version of Excel installed, or if it's installed in a different location.

Also, the error handling could be added to the code above so that if the initial instantiation of the Excel instance fails (say, because Excel is not installed or not properly registered), your code can continue. With a reference set, your whole Access application will fail if Excel is not installed.

Running sites on "localhost" is extremely slow

After building your project the website needs some time to walk through the new dll :). It's normal that loading a webpage after rebuilding takes some time. This shouldn't happen when only changing something in for example javascript.

How can I emulate a get request exactly like a web browser?

Are you sure the curl module honors ini_set('user_agent',...)? There is an option CURLOPT_USERAGENT described at http://docs.php.net/function.curl-setopt.
Could there also be a cookie tested by the server? That you can handle by using CURLOPT_COOKIE, CURLOPT_COOKIEFILE and/or CURLOPT_COOKIEJAR.

edit: Since the request uses https there might also be error in verifying the certificate, see CURLOPT_SSL_VERIFYPEER.

$url="https://new.aol.com/productsweb/subflows/ScreenNameFlow/AjaxSNAction.do?s=username&f=firstname&l=lastname";
$agent= 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.0.3705; .NET CLR 1.1.4322)';

$ch = curl_init();
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_VERBOSE, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_USERAGENT, $agent);
curl_setopt($ch, CURLOPT_URL,$url);
$result=curl_exec($ch);
var_dump($result);

Add two numbers and display result in textbox with Javascript

<script>
function myFunction() {
var y = parseInt(document.getElementById("txt1").value);
var z = parseInt(document.getElementById("txt2").value);
var x = y + z;
document.getElementById("result").innerHTML = x;
}
</script>
<p>
<label>Enter First Number : </label><br>
<input type="number" id="txt1" name="text1"><br/>
<label>Enter Second Number : </label><br>
<input type="number" id="txt2" name="text2">
</p>
<p>
<button onclick="myFunction()">Calculate</button>
</p>
<br/>
<p id="result"></p>

How to alter SQL in "Edit Top 200 Rows" in SSMS 2008

Similar to David Hall's response, if you are a non-coder, it may be easiest to right-click within results, then choose Pane > Criteria. This allows you to adjust sort, add filters, etc... without adjusting SQL code.

Could not resolve com.android.support:appcompat-v7:26.1.0 in Android Studio new project

Finally I fixed the problem by modifying build.gradle like this:

android {
    compileSdkVersion 26
    buildToolsVersion "26.0.2"

    defaultConfig {
        minSdkVersion 16
        targetSdkVersion 26
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    implementation 'com.android.support:design:26.1.0'
}

I've removed these lines as these will produce more errors:

testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'

Also I had same problem with migrating an existing project from 2.3 to 3.0.1 and with modifying the project gradle files like this, I came up with a working solution:

build.gradle (module app)

android {
    compileSdkVersion 27
    buildToolsVersion "27.0.1"

    defaultConfig {
        applicationId "com.mobaleghan.tablighcalendar"
        minSdkVersion 16
        targetSdkVersion 27
    }

dependencies {
    implementation 'com.android.support:appcompat-v7:25.1.0'
    implementation 'com.android.support:design:25.1.0'
    implementation 'com.android.support:preference-v7:25.1.0'
    implementation 'com.android.support:recyclerview-v7:25.1.0'
    implementation 'com.android.support:support-annotations:25.1.0'
    implementation 'com.android.support:support-v4:25.1.0'
    implementation 'com.android.support:cardview-v7:25.1.0'
    implementation 'com.google.android.apps.dashclock:dashclock-api:2.0.0'
}

Top level build.gradle

buildscript {
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.1'
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

'too many values to unpack', iterating over a dict. key=>string, value=>list

For lists, use enumerate

for field, possible_values in enumerate(fields):
    print(field, possible_values)

iteritems will not work for list objects

Error - replacement has [x] rows, data has [y]

The answer by @akrun certainly does the trick. For future googlers who want to understand why, here is an explanation...

The new variable needs to be created first.

The variable "valueBin" needs to be already in the df in order for the conditional assignment to work. Essentially, the syntax of the code is correct. Just add one line in front of the code chuck to create this name --

df$newVariableName <- NA

Then you continue with whatever conditional assignment rules you have, like

df$newVariableName[which(df$oldVariableName<=250)] <- "<=250"

I blame whoever wrote that package's error message... The debugging was made especially confusing by that error message. It is irrelevant information that you have two arrays in the df with different lengths. No. Simply create the new column first. For more details, consult this post https://www.r-bloggers.com/translating-weird-r-errors/

Sorting an IList in C#

Found this thread while I was looking for a solution to the exact problem described in the original post. None of the answers met my situation entirely, however. Brody's answer was pretty close. Here is my situation and solution I found to it.

I have two ILists of the same type returned by NHibernate and have emerged the two IList into one, hence the need for sorting.

Like Brody said I implemented an ICompare on the object (ReportFormat) which is the type of my IList:

 public class FormatCcdeSorter:IComparer<ReportFormat>
    {
       public int Compare(ReportFormat x, ReportFormat y)
        {
           return x.FormatCode.CompareTo(y.FormatCode);
        }
    }

I then convert the merged IList to an array of the same type:

ReportFormat[] myReports = new ReportFormat[reports.Count]; //reports is the merged IList

Then sort the array:

Array.Sort(myReports, new FormatCodeSorter());//sorting using custom comparer

Since one-dimensional array implements the interface System.Collections.Generic.IList<T>, the array can be used just like the original IList.

On Duplicate Key Update same as insert

Just in case you are able to utilize a scripting language to prepare your SQL queries, you could reuse field=value pairs by using SET instead of (a,b,c) VALUES(a,b,c).

An example with PHP:

$pairs = "a=$a,b=$b,c=$c";
$query = "INSERT INTO $table SET $pairs ON DUPLICATE KEY UPDATE $pairs";

Example table:

CREATE TABLE IF NOT EXISTS `tester` (
  `a` int(11) NOT NULL,
  `b` varchar(50) NOT NULL,
  `c` text NOT NULL,
  UNIQUE KEY `a` (`a`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;

Linux delete file with size 0

you would want to use find:

 find . -size 0 -delete

Best way to encode text data for XML in Java?

This question is eight years old and still not a fully correct answer! No, you should not have to import an entire third party API to do this simple task. Bad advice.

The following method will:

  • correctly handle characters outside the basic multilingual plane
  • escape characters required in XML
  • escape any non-ASCII characters, which is optional but common
  • replace illegal characters in XML 1.0 with the Unicode substitution character. There is no best option here - removing them is just as valid.

I've tried to optimise for the most common case, while still ensuring you could pipe /dev/random through this and get a valid string in XML.

public static String encodeXML(CharSequence s) {
    StringBuilder sb = new StringBuilder();
    int len = s.length();
    for (int i=0;i<len;i++) {
        int c = s.charAt(i);
        if (c >= 0xd800 && c <= 0xdbff && i + 1 < len) {
            c = ((c-0xd7c0)<<10) | (s.charAt(++i)&0x3ff);    // UTF16 decode
        }
        if (c < 0x80) {      // ASCII range: test most common case first
            if (c < 0x20 && (c != '\t' && c != '\r' && c != '\n')) {
                // Illegal XML character, even encoded. Skip or substitute
                sb.append("&#xfffd;");   // Unicode replacement character
            } else {
                switch(c) {
                  case '&':  sb.append("&amp;"); break;
                  case '>':  sb.append("&gt;"); break;
                  case '<':  sb.append("&lt;"); break;
                  // Uncomment next two if encoding for an XML attribute
//                  case '\''  sb.append("&apos;"); break;
//                  case '\"'  sb.append("&quot;"); break;
                  // Uncomment next three if you prefer, but not required
//                  case '\n'  sb.append("&#10;"); break;
//                  case '\r'  sb.append("&#13;"); break;
//                  case '\t'  sb.append("&#9;"); break;

                  default:   sb.append((char)c);
                }
            }
        } else if ((c >= 0xd800 && c <= 0xdfff) || c == 0xfffe || c == 0xffff) {
            // Illegal XML character, even encoded. Skip or substitute
            sb.append("&#xfffd;");   // Unicode replacement character
        } else {
            sb.append("&#x");
            sb.append(Integer.toHexString(c));
            sb.append(';');
        }
    }
    return sb.toString();
}

Edit: for those who continue to insist it foolish to write your own code for this when there are perfectly good Java APIs to deal with XML, you might like to know that the StAX API included with Oracle Java 8 (I haven't tested others) fails to encode CDATA content correctly: it doesn't escape ]]> sequences in the content. A third party library, even one that's part of the Java core, is not always the best option.

Returning a stream from File.OpenRead()

Try changing your code to this:

private void Test()
{            
    System.IO.MemoryStream data = new System.IO.MemoryStream(TestStream());

    byte[] buf = new byte[data.Length];
    data.Read(buf, 0, buf.Length);                       
}

Datatable vs Dataset

in 1.x there used to be things DataTables couldn't do which DataSets could (don't remember exactly what). All that was changed in 2.x. My guess is that's why a lot of examples still use DataSets. DataTables should be quicker as they are more lightweight. If you're only pulling a single resultset, its your best choice between the two.

How to show loading spinner in jQuery?

As well as setting global defaults for ajax events, you can set behaviour for specific elements. Perhaps just changing their class would be enough?

$('#myForm').ajaxSend( function() {
    $(this).addClass('loading');
});
$('#myForm').ajaxComplete( function(){
    $(this).removeClass('loading');
});

Example CSS, to hide #myForm with a spinner:

.loading {
    display: block;
    background: url(spinner.gif) no-repeat center middle;
    width: 124px;
    height: 124px;
    margin: 0 auto;
}
/* Hide all the children of the 'loading' element */
.loading * {
    display: none;  
}

Where to download visual studio express 2005?

Small tip for you. Microsoft frequently has 'launch parties' or 'launch events' in which they frequently distribute licensed, not for resale copies, of that product. I've gotten the last two versions of VS (2005 and 2008) by attending my local .NET user group chapter during those days.

How to determine equality for two JavaScript objects?

Some of the following solutions have problems with performance, functionality and style... They are not thought through enough, and some of them fail for different cases. I tried to address this problem in my own solution, and I would really much appreciate your feedback:

http://stamat.wordpress.com/javascript-object-comparison/

//Returns the object's class, Array, Date, RegExp, Object are of interest to us
var getClass = function(val) {
    return Object.prototype.toString.call(val)
        .match(/^\[object\s(.*)\]$/)[1];
};

//Defines the type of the value, extended typeof
var whatis = function(val) {

    if (val === undefined)
        return 'undefined';
    if (val === null)
        return 'null';

    var type = typeof val;

    if (type === 'object')
        type = getClass(val).toLowerCase();

    if (type === 'number') {
        if (val.toString().indexOf('.') > 0)
            return 'float';
        else
        return 'integer';
    }

    return type;
   };

var compareObjects = function(a, b) {
    if (a === b)
        return true;
    for (var i in a) {
        if (b.hasOwnProperty(i)) {
            if (!equal(a[i],b[i])) return false;
        } else {
            return false;
        }
    }

    for (var i in b) {
        if (!a.hasOwnProperty(i)) {
            return false;
        }
    }
    return true;
};

var compareArrays = function(a, b) {
    if (a === b)
        return true;
    if (a.length !== b.length)
        return false;
    for (var i = 0; i < a.length; i++){
        if(!equal(a[i], b[i])) return false;
    };
    return true;
};

var _equal = {};
_equal.array = compareArrays;
_equal.object = compareObjects;
_equal.date = function(a, b) {
    return a.getTime() === b.getTime();
};
_equal.regexp = function(a, b) {
    return a.toString() === b.toString();
};
//  uncoment to support function as string compare
//  _equal.fucntion =  _equal.regexp;



/*
 * Are two values equal, deep compare for objects and arrays.
 * @param a {any}
 * @param b {any}
 * @return {boolean} Are equal?
 */
var equal = function(a, b) {
    if (a !== b) {
        var atype = whatis(a), btype = whatis(b);

        if (atype === btype)
            return _equal.hasOwnProperty(atype) ? _equal[atype](a, b) : a==b;

        return false;
    }

    return true;
};

How to read file with space separated values in pandas

you can use regex as the delimiter:

pd.read_csv("whitespace.csv", header=None, delimiter=r"\s+")

Enter key press behaves like a Tab in Javascript

Thank you for the good script.

I have just added the shift event on the above function to go back between elements, I thought someone may need this.

$('body').on('keydown', 'input, select, textarea', function(e) {
var self = $(this)
  , form = self.parents('form:eq(0)')
  , focusable
  , next
  , prev
  ;

if (e.shiftKey) {
 if (e.keyCode == 13) {
     focusable =   form.find('input,a,select,button,textarea').filter(':visible');
     prev = focusable.eq(focusable.index(this)-1); 

     if (prev.length) {
        prev.focus();
     } else {
        form.submit();
    }
  }
}
  else
if (e.keyCode == 13) {
    focusable = form.find('input,a,select,button,textarea').filter(':visible');
    next = focusable.eq(focusable.index(this)+1);
    if (next.length) {
        next.focus();
    } else {
        form.submit();
    }
    return false;
}
});

MySQL root access from all hosts

I'm using AWS LightSail and for my instance to work, I had to change:

bind-address = 127.0.0.1

to

bind-address = <Private IP Assigned by Amazon>

Then I was able to connect remotely.

How to create a HTML Cancel button that redirects to a URL

it defaults to submitting a form, easiest way is to add "return false"

<button type="cancel" onclick="window.location='http://stackoverflow.com';return false;">Cancel</button>

adding a datatable in a dataset

I assume that you haven't set the TableName property of the DataTable, for example via constructor:

var tbl = new DataTable("dtImage");

If you don't provide a name, it will be automatically created with "Table1", the next table will get "Table2" and so on.

Then the solution would be to provide the TableName and then check with Contains(nameOfTable).

To clarify it: You'll get an ArgumentException if that DataTable already belongs to the DataSet (the same reference). You'll get a DuplicateNameException if there's already a DataTable in the DataSet with the same name(not case-sensitive).

http://msdn.microsoft.com/en-us/library/as4zy2kc.aspx

CSS @media print issues with background-color;

Two solutions that work (on modern Chrome at least - haven't tested beyond):

  1. !important right in the regular css declaration works (not even in the @media print)
  2. Use svg

How to convert xml into array in php?

Another option is the SimpleXML extension (I believe it comes standard with most php installs.)

http://php.net/manual/en/book.simplexml.php

The syntax looks something like this for your example

$xml = new SimpleXMLElement($xmlString);
echo $xml->bbb->cccc->dddd['Id'];
echo $xml->bbb->cccc->eeee['name'];
// or...........
foreach ($xml->bbb->cccc as $element) {
  foreach($element as $key => $val) {
   echo "{$key}: {$val}";
  }
}

Fastest way to convert a dict's keys & values from `unicode` to `str`?

Just use print(*(dict.keys()))

The * can be used for unpacking containers e.g. lists. For more info on * check this SO answer.

Hibernate table not mapped error in HQL query

Hibernate also is picky about the capitalization. By default it's going to be the class name with the First letter Capitalized. So if your class is called FooBar, don't pass "foobar". You have to pass "FooBar" with that exact capitalization for it to work.

Is there any JSON Web Token (JWT) example in C#?

I've never used it but there is a JWT implementation on NuGet.

Package: https://nuget.org/packages/JWT

Source: https://github.com/johnsheehan/jwt

.NET 4.0 compatible: https://www.nuget.org/packages/jose-jwt/

You can also go here: https://jwt.io/ and click "libraries".

Datatables - Search Box outside datatable

You can use the DataTables api to filter the table. So all you need is your own input field with a keyup event that triggers the filter function to DataTables. With css or jquery you can hide/remove the existing search input field. Or maybe DataTables has a setting to remove/not-include it.

Checkout the Datatables API documentation on this.

Example:

HTML

<input type="text" id="myInputTextField">

JS

oTable = $('#myTable').DataTable();   //pay attention to capital D, which is mandatory to retrieve "api" datatables' object, as @Lionel said
$('#myInputTextField').keyup(function(){
      oTable.search($(this).val()).draw() ;
})

Getting the error "Java.lang.IllegalStateException Activity has been destroyed" when using tabs with ViewPager

The bug has been fixed in the latest androidx version. And the famous workaround will cause crash now. so we need not it now.

Generating an MD5 checksum of a file

In Python 3.8+ you can do

import hashlib
with open("your_filename.txt", "rb") as f:
    file_hash = hashlib.md5()
    while chunk := f.read(8192):
        file_hash.update(chunk)

print(file_hash.digest())
print(file_hash.hexdigest())  # to get a printable str instead of bytes

Consider using hashlib.blake2b instead of md5 (just replace md5 with blake2b in the above snippet). It's cryptographically secure and faster than MD5.

Difference between h:button and h:commandButton

h:button - clicking on a h:button issues a bookmarkable GET request.

h:commandbutton - Instead of a get request, h:commandbutton issues a POST request which sends the form data back to the server.

Create a list from two object lists with linq

There are a few pieces to doing this, assuming each list does not contain duplicates, Name is a unique identifier, and neither list is ordered.

First create an append extension method to get a single list:

static class Ext {
  public static IEnumerable<T> Append(this IEnumerable<T> source,
                                      IEnumerable<T> second) {
    foreach (T t in source) { yield return t; }
    foreach (T t in second) { yield return t; }
  }
}

Thus can get a single list:

var oneList = list1.Append(list2);

Then group on name

var grouped = oneList.Group(p => p.Name);

Then can process each group with a helper to process one group at a time

public Person MergePersonGroup(IGrouping<string, Person> pGroup) {
  var l = pGroup.ToList(); // Avoid multiple enumeration.
  var first = l.First();
  var result = new Person {
    Name = first.Name,
    Value = first.Value
  };
  if (l.Count() == 1) {
    return result;
  } else if (l.Count() == 2) {
    result.Change = first.Value - l.Last().Value;
    return result;
  } else {
    throw new ApplicationException("Too many " + result.Name);
  }
}

Which can be applied to each element of grouped:

var finalResult = grouped.Select(g => MergePersonGroup(g));

(Warning: untested.)

Spring Data JPA Update @Query not updating?

The underlying problem here is the 1st level cache of JPA. From the JPA spec Version 2.2 section 3.1. emphasise is mine:

An EntityManager instance is associated with a persistence context. A persistence context is a set of entity instances in which for any persistent entity identity there is a unique entity instance.

This is important because JPA tracks changes to that entity in order to flush them to the database. As a side effect it also means within a single persistence context an entity gets only loaded once. This why reloading the changed entity doesn't have any effect.

You have a couple of options how to handle this:

  1. Evict the entity from the EntityManager. This may be done by calling EntityManager.detach, annotating the updating method with @Modifying(clearAutomatically = true) which evicts all entities. Make sure changes to these entities get flushed first or you might end up loosing changes.

  2. Use EntityManager.refresh().

  3. Use a different persistence context to load the entity. The easiest way to do this is to do it in a separate transaction. With Spring this can be done by having separate methods annotated with @Transactional on beans called from a bean not annotated with @Transactional. Another way is to use a TransactionTemplate which works especially nicely in tests where it makes transaction boundaries very visible.

What is "export default" in JavaScript?

export default is used to export a single class, function or primitive.

export default function() { } can be used when the function has no name. There can only be one default export in a file.

Read more

MySQL: Error dropping database (errno 13; errno 17; errno 39)

In my case it was due to 'lower_case_table_names' parameter.

The error number 39 thrown out when I tried to drop the databases which consists upper case table names with lower_case_table_names parameter is enabled.

This is fixed by reverting back the lower case parameter changes to the previous state.

Disable button in WPF?

By code:

btn_edit.IsEnabled = true;

By XAML:

<Button Content="Edit data" Grid.Column="1" Name="btn_edit" Grid.Row="1" IsEnabled="False" />

What is the difference between a static and const variable?

Constants can't be changed, static variables have more to do with how they are allocated and where they are accessible.

Check out this site.

How do I represent a time only value in .NET?

Here's a full featured TimeOfDay class.

This is overkill for simple cases, but if you need more advanced functionality like I did, this may help.

It can handle the corner cases, some basic math, comparisons, interaction with DateTime, parsing, etc.

Below is the source code for the TimeOfDay class. You can see usage examples and learn more here:

This class uses DateTime for most of its internal calculations and comparisons so that we can leverage all of the knowledge already embedded in DateTime.

// Author: Steve Lautenschlager, CambiaResearch.com
// License: MIT

using System;
using System.Text.RegularExpressions;

namespace Cambia
{
    public class TimeOfDay
    {
        private const int MINUTES_PER_DAY = 60 * 24;
        private const int SECONDS_PER_DAY = SECONDS_PER_HOUR * 24;
        private const int SECONDS_PER_HOUR = 3600;
        private static Regex _TodRegex = new Regex(@"\d?\d:\d\d:\d\d|\d?\d:\d\d");

        public TimeOfDay()
        {
            Init(0, 0, 0);
        }
        public TimeOfDay(int hour, int minute, int second = 0)
        {
            Init(hour, minute, second);
        }
        public TimeOfDay(int hhmmss)
        {
            Init(hhmmss);
        }
        public TimeOfDay(DateTime dt)
        {
            Init(dt);
        }
        public TimeOfDay(TimeOfDay td)
        {
            Init(td.Hour, td.Minute, td.Second);
        }

        public int HHMMSS
        {
            get
            {
                return Hour * 10000 + Minute * 100 + Second;
            }
        }
        public int Hour { get; private set; }
        public int Minute { get; private set; }
        public int Second { get; private set; }
        public double TotalDays
        {
            get
            {
                return TotalSeconds / (24d * SECONDS_PER_HOUR);
            }
        }
        public double TotalHours
        {
            get
            {
                return TotalSeconds / (1d * SECONDS_PER_HOUR);
            }
        }
        public double TotalMinutes
        {
            get
            {
                return TotalSeconds / 60d;
            }
        }
        public int TotalSeconds
        {
            get
            {
                return Hour * 3600 + Minute * 60 + Second;
            }
        }
        public bool Equals(TimeOfDay other)
        {
            if (other == null) { return false; }
            return TotalSeconds == other.TotalSeconds;
        }
        public override bool Equals(object obj)
        {
            if (obj == null) { return false; }
            TimeOfDay td = obj as TimeOfDay;
            if (td == null) { return false; }
            else { return Equals(td); }
        }
        public override int GetHashCode()
        {
            return TotalSeconds;
        }
        public DateTime ToDateTime(DateTime dt)
        {
            return new DateTime(dt.Year, dt.Month, dt.Day, Hour, Minute, Second);
        }
        public override string ToString()
        {
            return ToString("HH:mm:ss");
        }
        public string ToString(string format)
        {
            DateTime now = DateTime.Now;
            DateTime dt = new DateTime(now.Year, now.Month, now.Day, Hour, Minute, Second);
            return dt.ToString(format);
        }
        public TimeSpan ToTimeSpan()
        {
            return new TimeSpan(Hour, Minute, Second);
        }
        public DateTime ToToday()
        {
            var now = DateTime.Now;
            return new DateTime(now.Year, now.Month, now.Day, Hour, Minute, Second);
        }

        #region -- Static --
        public static TimeOfDay Midnight { get { return new TimeOfDay(0, 0, 0); } }
        public static TimeOfDay Noon { get { return new TimeOfDay(12, 0, 0); } }
        public static TimeOfDay operator -(TimeOfDay t1, TimeOfDay t2)
        {
            DateTime now = DateTime.Now;
            DateTime dt1 = new DateTime(now.Year, now.Month, now.Day, t1.Hour, t1.Minute, t1.Second);
            TimeSpan ts = new TimeSpan(t2.Hour, t2.Minute, t2.Second);
            DateTime dt2 = dt1 - ts;
            return new TimeOfDay(dt2);
        }
        public static bool operator !=(TimeOfDay t1, TimeOfDay t2)
        {
            if (ReferenceEquals(t1, t2)) { return true; }
            else if (ReferenceEquals(t1, null)) { return true; }
            else
            {
                return t1.TotalSeconds != t2.TotalSeconds;
            }
        }
        public static bool operator !=(TimeOfDay t1, DateTime dt2)
        {
            if (ReferenceEquals(t1, null)) { return false; }
            DateTime dt1 = new DateTime(dt2.Year, dt2.Month, dt2.Day, t1.Hour, t1.Minute, t1.Second);
            return dt1 != dt2;
        }
        public static bool operator !=(DateTime dt1, TimeOfDay t2)
        {
            if (ReferenceEquals(t2, null)) { return false; }
            DateTime dt2 = new DateTime(dt1.Year, dt1.Month, dt1.Day, t2.Hour, t2.Minute, t2.Second);
            return dt1 != dt2;
        }
        public static TimeOfDay operator +(TimeOfDay t1, TimeOfDay t2)
        {
            DateTime now = DateTime.Now;
            DateTime dt1 = new DateTime(now.Year, now.Month, now.Day, t1.Hour, t1.Minute, t1.Second);
            TimeSpan ts = new TimeSpan(t2.Hour, t2.Minute, t2.Second);
            DateTime dt2 = dt1 + ts;
            return new TimeOfDay(dt2);
        }
        public static bool operator <(TimeOfDay t1, TimeOfDay t2)
        {
            if (ReferenceEquals(t1, t2)) { return true; }
            else if (ReferenceEquals(t1, null)) { return true; }
            else
            {
                return t1.TotalSeconds < t2.TotalSeconds;
            }
        }
        public static bool operator <(TimeOfDay t1, DateTime dt2)
        {
            if (ReferenceEquals(t1, null)) { return false; }
            DateTime dt1 = new DateTime(dt2.Year, dt2.Month, dt2.Day, t1.Hour, t1.Minute, t1.Second);
            return dt1 < dt2;
        }
        public static bool operator <(DateTime dt1, TimeOfDay t2)
        {
            if (ReferenceEquals(t2, null)) { return false; }
            DateTime dt2 = new DateTime(dt1.Year, dt1.Month, dt1.Day, t2.Hour, t2.Minute, t2.Second);
            return dt1 < dt2;
        }
        public static bool operator <=(TimeOfDay t1, TimeOfDay t2)
        {
            if (ReferenceEquals(t1, t2)) { return true; }
            else if (ReferenceEquals(t1, null)) { return true; }
            else
            {
                if (t1 == t2) { return true; }
                return t1.TotalSeconds <= t2.TotalSeconds;
            }
        }
        public static bool operator <=(TimeOfDay t1, DateTime dt2)
        {
            if (ReferenceEquals(t1, null)) { return false; }
            DateTime dt1 = new DateTime(dt2.Year, dt2.Month, dt2.Day, t1.Hour, t1.Minute, t1.Second);
            return dt1 <= dt2;
        }
        public static bool operator <=(DateTime dt1, TimeOfDay t2)
        {
            if (ReferenceEquals(t2, null)) { return false; }
            DateTime dt2 = new DateTime(dt1.Year, dt1.Month, dt1.Day, t2.Hour, t2.Minute, t2.Second);
            return dt1 <= dt2;
        }
        public static bool operator ==(TimeOfDay t1, TimeOfDay t2)
        {
            if (ReferenceEquals(t1, t2)) { return true; }
            else if (ReferenceEquals(t1, null)) { return true; }
            else { return t1.Equals(t2); }
        }
        public static bool operator ==(TimeOfDay t1, DateTime dt2)
        {
            if (ReferenceEquals(t1, null)) { return false; }
            DateTime dt1 = new DateTime(dt2.Year, dt2.Month, dt2.Day, t1.Hour, t1.Minute, t1.Second);
            return dt1 == dt2;
        }
        public static bool operator ==(DateTime dt1, TimeOfDay t2)
        {
            if (ReferenceEquals(t2, null)) { return false; }
            DateTime dt2 = new DateTime(dt1.Year, dt1.Month, dt1.Day, t2.Hour, t2.Minute, t2.Second);
            return dt1 == dt2;
        }
        public static bool operator >(TimeOfDay t1, TimeOfDay t2)
        {
            if (ReferenceEquals(t1, t2)) { return true; }
            else if (ReferenceEquals(t1, null)) { return true; }
            else
            {
                return t1.TotalSeconds > t2.TotalSeconds;
            }
        }
        public static bool operator >(TimeOfDay t1, DateTime dt2)
        {
            if (ReferenceEquals(t1, null)) { return false; }
            DateTime dt1 = new DateTime(dt2.Year, dt2.Month, dt2.Day, t1.Hour, t1.Minute, t1.Second);
            return dt1 > dt2;
        }
        public static bool operator >(DateTime dt1, TimeOfDay t2)
        {
            if (ReferenceEquals(t2, null)) { return false; }
            DateTime dt2 = new DateTime(dt1.Year, dt1.Month, dt1.Day, t2.Hour, t2.Minute, t2.Second);
            return dt1 > dt2;
        }
        public static bool operator >=(TimeOfDay t1, TimeOfDay t2)
        {
            if (ReferenceEquals(t1, t2)) { return true; }
            else if (ReferenceEquals(t1, null)) { return true; }
            else
            {
                return t1.TotalSeconds >= t2.TotalSeconds;
            }
        }
        public static bool operator >=(TimeOfDay t1, DateTime dt2)
        {
            if (ReferenceEquals(t1, null)) { return false; }
            DateTime dt1 = new DateTime(dt2.Year, dt2.Month, dt2.Day, t1.Hour, t1.Minute, t1.Second);
            return dt1 >= dt2;
        }
        public static bool operator >=(DateTime dt1, TimeOfDay t2)
        {
            if (ReferenceEquals(t2, null)) { return false; }
            DateTime dt2 = new DateTime(dt1.Year, dt1.Month, dt1.Day, t2.Hour, t2.Minute, t2.Second);
            return dt1 >= dt2;
        }
        /// <summary>
        /// Input examples:
        /// 14:21:17            (2pm 21min 17sec)
        /// 02:15               (2am 15min 0sec)
        /// 2:15                (2am 15min 0sec)
        /// 2/1/2017 14:21      (2pm 21min 0sec)
        /// TimeOfDay=15:13:12  (3pm 13min 12sec)
        /// </summary>
        public static TimeOfDay Parse(string s)
        {
            // We will parse any section of the text that matches this
            // pattern: dd:dd or dd:dd:dd where the first doublet can
            // be one or two digits for the hour.  But minute and second
            // must be two digits.

            Match m = _TodRegex.Match(s);
            string text = m.Value;
            string[] fields = text.Split(':');
            if (fields.Length < 2) { throw new ArgumentException("No valid time of day pattern found in input text"); }
            int hour = Convert.ToInt32(fields[0]);
            int min = Convert.ToInt32(fields[1]);
            int sec = fields.Length > 2 ? Convert.ToInt32(fields[2]) : 0;

            return new TimeOfDay(hour, min, sec);
        }
        #endregion

        private void Init(int hour, int minute, int second)
        {
            if (hour < 0 || hour > 23) { throw new ArgumentException("Invalid hour, must be from 0 to 23."); }
            if (minute < 0 || minute > 59) { throw new ArgumentException("Invalid minute, must be from 0 to 59."); }
            if (second < 0 || second > 59) { throw new ArgumentException("Invalid second, must be from 0 to 59."); }
            Hour = hour;
            Minute = minute;
            Second = second;
        }
        private void Init(int hhmmss)
        {
            int hour = hhmmss / 10000;
            int min = (hhmmss - hour * 10000) / 100;
            int sec = (hhmmss - hour * 10000 - min * 100);
            Init(hour, min, sec);
        }
        private void Init(DateTime dt)
        {
            Init(dt.Hour, dt.Minute, dt.Second);
        }
    }
}

Pushing to Git returning Error Code 403 fatal: HTTP request failed

  1. Click on your repository
  2. On the right hand side, click on "Settings"
  3. On the left hand side option panel, click on "Collaborators"
  4. Add the person name you know in GitHub
  5. Click "Add Collaborators"

After this our "Push to Git" worked fine.

Django DateField default options

Your mistake is using the datetime module instead of the date module. You meant to do this:

from datetime import date
date = models.DateField(_("Date"), default=date.today)

If you only want to capture the current date the proper way to handle this is to use the auto_now_add parameter:

date = models.DateField(_("Date"), auto_now_add=True)

However, the modelfield docs clearly state that auto_now_add and auto_now will always use the current date and are not a default value that you can override.

Import .bak file to a database in SQL server

  1. Copy your backup .bak file in the following location of your pc : C:\Program Files\Microsoft SQL Server\MSSQL11.SQLEXPRESS\MSSQL\DATA
  2. Connect to a server you want to store your DB
  3. Right-click Database
  4. Click Restore
  5. Choose the Device radio button under the source section
  6. Click Add.
  7. Navigate to the path where your .bak file is stored, select it and click OK
  8. Enter the destination of your DB
  9. Enter the name by which you want to store your DB
  10. Click OK

The above solutions missed out on where to keep your backup (.bak) file. This should do the trick. It worked for me.

ValueError: Length of values does not match length of index | Pandas DataFrame.unique()

The error comes up when you are trying to assign a list of numpy array of different length to a data frame, and it can be reproduced as follows:

A data frame of four rows:

df = pd.DataFrame({'A': [1,2,3,4]})

Now trying to assign a list/array of two elements to it:

df['B'] = [3,4]   # or df['B'] = np.array([3,4])

Both errors out:

ValueError: Length of values does not match length of index

Because the data frame has four rows but the list and array has only two elements.

Work around Solution (use with caution): convert the list/array to a pandas Series, and then when you do assignment, missing index in the Series will be filled with NaN:

df['B'] = pd.Series([3,4])

df
#   A     B
#0  1   3.0
#1  2   4.0
#2  3   NaN          # NaN because the value at index 2 and 3 doesn't exist in the Series
#3  4   NaN

For your specific problem, if you don't care about the index or the correspondence of values between columns, you can reset index for each column after dropping the duplicates:

df.apply(lambda col: col.drop_duplicates().reset_index(drop=True))

#   A     B
#0  1   1.0
#1  2   5.0
#2  7   9.0
#3  8   NaN

Remove characters except digits from string using Python?

along the lines of bayer's answer:

''.join(i for i in s if i.isdigit())

call a static method inside a class?

Let's assume this is your class:

class Test
{
    private $baz = 1;

    public function foo() { ... }

    public function bar() 
    {
        printf("baz = %d\n", $this->baz);
    }

    public static function staticMethod() { echo "static method\n"; }
}

From within the foo() method, let's look at the different options:

$this->staticMethod();

So that calls staticMethod() as an instance method, right? It does not. This is because the method is declared as public static the interpreter will call it as a static method, so it will work as expected. It could be argued that doing so makes it less obvious from the code that a static method call is taking place.

$this::staticMethod();

Since PHP 5.3 you can use $var::method() to mean <class-of-$var>::; this is quite convenient, though the above use-case is still quite unconventional. So that brings us to the most common way of calling a static method:

self::staticMethod();

Now, before you start thinking that the :: is the static call operator, let me give you another example:

self::bar();

This will print baz = 1, which means that $this->bar() and self::bar() do exactly the same thing; that's because :: is just a scope resolution operator. It's there to make parent::, self:: and static:: work and give you access to static variables; how a method is called depends on its signature and how the caller was called.

To see all of this in action, see this 3v4l.org output.

Notify ObservableCollection when Item changes

A simple solution is to use BindingList<T> instead of ObservableCollection<T> . Indeed the BindingList relay item change notifications. So with a binding list, if the item implements the interface INotifyPropertyChanged then you can simply get notifications using the ListChanged event.

See also this SO answer.

Find stored procedure by name

Option 1: In SSMS go to View > Object Explorer Details or press F7. Use the Search box. Finally in the displayed list right click and select Synchronize to find the object in the Object Explorer tree.

Object Explorer Details

Option 2: Install an Add-On like dbForge Search. Right click on the displayed list and select Find in Object Explorer.

enter image description here

Execute stored procedure with an Output parameter?

you can do this :

declare @rowCount int
exec yourStoredProcedureName @outputparameterspOf = @rowCount output

How many bits or bytes are there in a character?

It depends what is the character and what encoding it is in:

  • An ASCII character in 8-bit ASCII encoding is 8 bits (1 byte), though it can fit in 7 bits.

  • An ISO-8895-1 character in ISO-8859-1 encoding is 8 bits (1 byte).

  • A Unicode character in UTF-8 encoding is between 8 bits (1 byte) and 32 bits (4 bytes).

  • A Unicode character in UTF-16 encoding is between 16 (2 bytes) and 32 bits (4 bytes), though most of the common characters take 16 bits. This is the encoding used by Windows internally.

  • A Unicode character in UTF-32 encoding is always 32 bits (4 bytes).

  • An ASCII character in UTF-8 is 8 bits (1 byte), and in UTF-16 - 16 bits.

  • The additional (non-ASCII) characters in ISO-8895-1 (0xA0-0xFF) would take 16 bits in UTF-8 and UTF-16.

That would mean that there are between 0.03125 and 0.125 characters in a bit.

What are the "spec.ts" files generated by Angular CLI for?

.spec.ts file is used for unit testing of your application.

If you don't to get it generated just use --spec=false while creating new Component. Like this

ng generate component --spec=false mycomponentName

What's "tools:context" in Android layout files?

tools:context=".MainActivity" thisline is used in xml file which indicate that which java source file is used to access this xml file. it means show this xml preview for perticular java files.

Trying to make bootstrap modal wider

You could try:

.modal.modal-wide .modal-dialog {
  width: 90%;
}

.modal-wide .modal-body {
  overflow-y: auto;
}

Just add .modal-wide to your classes

Could not find a base address that matches scheme https for the endpoint with binding WebHttpBinding. Registered base address schemes are [http]

In the endpoint tag you need to include the property address=""

<endpoint address="" binding="webHttpBinding" bindingConfiguration="SecureBasicRest" behaviorConfiguration="svcEndpoint" name="webHttp" contract="SvcContract.Authenticate" />

Check if number is decimal

Simplest solution is

if(is_float(2.3)){

 echo 'true';

}