Programs & Examples On #Fgets

Anything related to C or C++ standard library functions `fgets` (C) or `std::fgets` (C++). These functions are used to read a sequence of characters from an input stream and to write it into a character buffer as a string.

Read each line of txt file to new array element

$lines = array();
while (($line = fgets($file)) !== false)
    array_push($lines, $line);

Obviously, you'll need to create a file handle first and store it in $file.

Removing trailing newline character from fgets() input

Below is a fast approach to remove a potential '\n' from a string saved by fgets().
It uses strlen(), with 2 tests.

char buffer[100];
if (fgets(buffer, sizeof buffer, stdin) != NULL) {

  size_t len = strlen(buffer);
  if (len > 0 && buffer[len-1] == '\n') {
    buffer[--len] = '\0';
  }

Now use buffer and len as needed.

This method has the side benefit of a len value for subsequent code. It can be easily faster than strchr(Name, '\n'). Ref YMMV, but both methods work.


buffer, from the original fgets() will not contain in "\n" under some circumstances:
A) The line was too long for buffer so only char preceding the '\n' is saved in buffer. The unread characters remain in the stream.
B) The last line in the file did not end with a '\n'.

If input has embedded null characters '\0' in it somewhere, the length reported by strlen() will not include the '\n' location.


Some other answers' issues:

  1. strtok(buffer, "\n"); fails to remove the '\n' when buffer is "\n". From this answer - amended after this answer to warn of this limitation.

  2. The following fails on rare occasions when the first char read by fgets() is '\0'. This happens when input begins with an embedded '\0'. Then buffer[len -1] becomes buffer[SIZE_MAX] accessing memory certainly outside the legitimate range of buffer. Something a hacker may try or found in foolishly reading UTF16 text files. This was the state of an answer when this answer was written. Later a non-OP edited it to include code like this answer's check for "".

    size_t len = strlen(buffer);
    if (buffer[len - 1] == '\n') {  // FAILS when len == 0
      buffer[len -1] = '\0';
    }
    
  3. sprintf(buffer,"%s",buffer); is undefined behavior: Ref. Further, it does not save any leading, separating or trailing whitespace. Now deleted.

  4. [Edit due to good later answer] There are no problems with the 1 liner buffer[strcspn(buffer, "\n")] = 0; other than performance as compared to the strlen() approach. Performance in trimming is usually not an issue given code is doing I/O - a black hole of CPU time. Should following code need the string's length or is highly performance conscious, use this strlen() approach. Else the strcspn() is a fine alternative.

How to read from stdin with fgets()?

You have a wrong idea of what fgets returns. Take a look at this: http://www.cplusplus.com/reference/clibrary/cstdio/fgets/

It returns null when it finds an EOF character. Try running the program above and pressing CTRL+D (or whatever combination is your EOF character), and the loop will exit succesfully.

How do you want to detect the end of the input? Newline? Dot (you said sentence xD)?

Why is the gets function so dangerous that it should not be used?

fgets.

To read from the stdin:

char string[512];

fgets(string, sizeof(string), stdin); /* no buffer overflows here, you're safe! */

Two's Complement in Python

It's not built in, but if you want unusual length numbers then you could use the bitstring module.

>>> from bitstring import Bits
>>> a = Bits(bin='111111111111')
>>> a.int
-1

The same object can equivalently be created in several ways, including

>>> b = Bits(int=-1, length=12)

It just behaves like a string of bits of arbitrary length, and uses properties to get different interpretations:

>>> print a.int, a.uint, a.bin, a.hex, a.oct
-1 4095 111111111111 fff 7777

How can I upgrade specific packages using pip and a requirements file?

This solved the issue for me:

pip install -I --upgrade psutil --force

Afterwards just uninstall psutil with the new version and hop you can suddenly install the older version (:

Regex to check if valid URL that ends in .jpg, .png, or .gif

In general, you're better off validating URLs using built-in library or framework functions, rather than rolling your own regular expressions to do this - see What is the best regular expression to check if a string is a valid URL for details.

If you are keen on doing this, though, check out this question:

Getting parts of a URL (Regex)

Then, once you're satisfied with the URL (by whatever means you used to validate it), you could either use a simple "endswith" type string operator to check the extension, or a simple regex like

(?i)\.(jpg|png|gif)$

How do you UrlEncode without using System.Web?

In .Net 4.5+ use WebUtility

Just for formatting I'm submitting this as an answer.

Couldn't find any good examples comparing them so:

string testString = "http://test# space 123/text?var=val&another=two";
Console.WriteLine("UrlEncode:         " + System.Web.HttpUtility.UrlEncode(testString));
Console.WriteLine("EscapeUriString:   " + Uri.EscapeUriString(testString));
Console.WriteLine("EscapeDataString:  " + Uri.EscapeDataString(testString));
Console.WriteLine("EscapeDataReplace: " + Uri.EscapeDataString(testString).Replace("%20", "+"));

Console.WriteLine("HtmlEncode:        " + System.Web.HttpUtility.HtmlEncode(testString));
Console.WriteLine("UrlPathEncode:     " + System.Web.HttpUtility.UrlPathEncode(testString));

//.Net 4.0+
Console.WriteLine("WebUtility.HtmlEncode: " + WebUtility.HtmlEncode(testString));
//.Net 4.5+
Console.WriteLine("WebUtility.UrlEncode:  " + WebUtility.UrlEncode(testString));

Outputs:

UrlEncode:             http%3a%2f%2ftest%23+space+123%2ftext%3fvar%3dval%26another%3dtwo
EscapeUriString:       http://test#%20space%20123/text?var=val&another=two
EscapeDataString:      http%3A%2F%2Ftest%23%20space%20123%2Ftext%3Fvar%3Dval%26another%3Dtwo
EscapeDataReplace:     http%3A%2F%2Ftest%23+space+123%2Ftext%3Fvar%3Dval%26another%3Dtwo

HtmlEncode:            http://test# space 123/text?var=val&another=two
UrlPathEncode:         http://test#%20space%20123/text?var=val&another=two

//.Net 4.0+
WebUtility.HtmlEncode: http://test# space 123/text?var=val&another=two
//.Net 4.5+
WebUtility.UrlEncode:  http%3A%2F%2Ftest%23+space+123%2Ftext%3Fvar%3Dval%26another%3Dtwo

In .Net 4.5+ use WebUtility.UrlEncode

This appears to replicate HttpUtility.UrlEncode (pre-v4.0) for the more common characters:
Uri.EscapeDataString(testString).Replace("%20", "+").Replace("'", "%27").Replace("~", "%7E")
Note: EscapeUriString will keep a valid uri string, which causes it to use as many plaintext characters as possible.

See this answer for a Table Comparing the various Encodings:
https://stackoverflow.com/a/11236038/555798

Line Breaks All of them listed here (other than HttpUtility.HtmlEncode) will convert "\n\r" into %0a%0d or %0A%0D

Please feel free to edit this and add new characters to my test string, or leave them in the comments and I'll edit it.

Count number of lines in a git repository

I was playing around with cmder (http://gooseberrycreative.com/cmder/) and I wanted to count the lines of html,css,java and javascript. While some of the answers above worked, or pattern in grep didn't - I found here (https://unix.stackexchange.com/questions/37313/how-do-i-grep-for-multiple-patterns) that I had to escape it

So this is what I use now:

git ls-files | grep "\(.html\|.css\|.js\|.java\)$" | xargs wc -l

Configuration with name 'default' not found. Android Studio

In my setting.gradle, I included a module that does not exist. Once I removed it, it started working. This could be another way to fix this issue

How do I make a newline after a twitter bootstrap element?

Using br elements is fine, and as long as you don't need a lot of space between elements, is actually a logical thing to do as anyone can read your code and understand what spacing logic you are using.

The alternative is to create a custom class for white space. In bootstrap 4 you can use

<div class="w-100"></div>

to make a blank row across the page, but this is no different to using the <br> tag. The downside to creating a custom class for white space is that it can be a pain to read for others who view your code. A custom class would also apply the same amount of white space each time you used it, so if you wanted different amounts of white space on the same page, then you would need to create several white space classes.

In most cases, it is just easier to use <br> or <div class="w-100"></div> for the sake of ease and readability. it doesn't look pretty, but it works.

How do I check that multiple keys are in a dict in a single pass?

While I like Alex Martelli's answer, it doesn't seem Pythonic to me. That is, I thought an important part of being Pythonic is to be easily understandable. With that goal, <= isn't easy to understand.

While it's more characters, using issubset() as suggested by Karl Voigtland's answer is more understandable. Since that method can use a dictionary as an argument, a short, understandable solution is:

foo = {'foo': 1, 'zip': 2, 'zam': 3, 'bar': 4}

if set(('foo', 'bar')).issubset(foo):
    #do stuff

I'd like to use {'foo', 'bar'} in place of set(('foo', 'bar')), because it's shorter. However, it's not that understandable and I think the braces are too easily confused as being a dictionary.

How to change font size on part of the page in LaTeX?

http://en.wikibooks.org/wiki/LaTeX/Formatting

use \alltt environment instead. Then set size using the same commands as outside verbatim environment.

Unioning two tables with different number of columns

Add extra columns as null for the table having less columns like

Select Col1, Col2, Col3, Col4, Col5 from Table1
Union
Select Col1, Col2, Col3, Null as Col4, Null as Col5 from Table2

How do you do a limit query in JPQL or HQL?

If can manage a limit in this mode

public List<ExampleModel> listExampleModel() {
    return listExampleModel(null, null);
}

public List<ExampleModel> listExampleModel(Integer first, Integer count) {
    Query tmp = getSession().createQuery("from ExampleModel");

    if (first != null)
        tmp.setFirstResult(first);
    if (count != null)
        tmp.setMaxResults(count);

    return (List<ExampleModel>)tmp.list();
}

This is a really simple code to handle a limit or a list.

"unable to locate adb" using Android Studio

Got it to work go to the local.properties file under your build.gradle files to find out the PATH to your SDK, from the SDK location go into the platform-tools folder and look and see if you have adb.exe. If not go to http://adbshell.com/downloads and download ADB KITS. Copy the zip folder's contents into the platform-tools folder and re-make your project.

I didn't need to update the PATH in the Extended Controls Settings section on the emulator, I left Use detected ADB location settings on. Hope this makes this faster for you !

How do I make a splash screen?

Another approach is achieved by using CountDownTimer

@Override
public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.splashscreen);

 new CountDownTimer(5000, 1000) { //5 seconds
      public void onTick(long millisUntilFinished) {
          mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
      }

     public void onFinish() {
          startActivity(new Intent(SplashActivity.this, MainActivity.class));
          finish();
     }

  }.start();
}

nginx: connect() failed (111: Connection refused) while connecting to upstream

I don't think that solution would work anyways because you will see some error message in your error log file.

The solution was a lot easier than what I thought.

simply, open the following path to your php5-fpm

sudo nano /etc/php5/fpm/pool.d/www.conf

or if you're the admin 'root'

nano /etc/php5/fpm/pool.d/www.conf

Then find this line and uncomment it:

listen.allowed_clients = 127.0.0.1

This solution will make you be able to use listen = 127.0.0.1:9000 in your vhost blocks

like this: fastcgi_pass 127.0.0.1:9000;

after you make the modifications, all you need is to restart or reload both Nginx and Php5-fpm

Php5-fpm

sudo service php5-fpm restart

or

sudo service php5-fpm reload

Nginx

sudo service nginx restart

or

sudo service nginx reload

From the comments:

Also comment

;listen = /var/run/php5-fpm.sock 

and add

listen = 9000

How to check the Angular version?

In Command line we can check our installed ng version.

ng -v OR ng --version OR ng version

This will give you like this :

 _                      _                 ____ _     ___

   / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
  / ? \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | |
 / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | |
/_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
               |___/

Angular CLI: 1.6.5
Node: 8.0.0
OS: linux x64
Angular: 
...

Write and read a list from file

If you don't need it to be human-readable/editable, the easiest solution is to just use pickle.

To write:

with open(the_filename, 'wb') as f:
    pickle.dump(my_list, f)

To read:

with open(the_filename, 'rb') as f:
    my_list = pickle.load(f)

If you do need them to be human-readable, we need more information.

If my_list is guaranteed to be a list of strings with no embedded newlines, just write them one per line:

with open(the_filename, 'w') as f:
    for s in my_list:
        f.write(s + '\n')

with open(the_filename, 'r') as f:
    my_list = [line.rstrip('\n') for line in f]

If they're Unicode strings rather than byte strings, you'll want to encode them. (Or, worse, if they're byte strings, but not necessarily in the same encoding as your system default.)

If they might have newlines, or non-printable characters, etc., you can use escaping or quoting. Python has a variety of different kinds of escaping built into the stdlib.

Let's use unicode-escape here to solve both of the above problems at once:

with open(the_filename, 'w') as f:
    for s in my_list:
        f.write((s + u'\n').encode('unicode-escape'))

with open(the_filename, 'r') as f:
    my_list = [line.decode('unicode-escape').rstrip(u'\n') for line in f]

You can also use the 3.x-style solution in 2.x, with either the codecs module or the io module:*

import io

with io.open(the_filename, 'w', encoding='unicode-escape') as f:
    f.writelines(line + u'\n' for line in my_list)

with open(the_filename, 'r') as f:
    my_list = [line.rstrip(u'\n') for line in f]

* TOOWTDI, so which is the one obvious way? It depends… For the short version: if you need to work with Python versions before 2.6, use codecs; if not, use io.

How to compare two strings are equal in value, what is the best method?

Not forgetting

.equalsIgnoreCase(String)

if you're not worried about that sort of thing...

Build and Install unsigned apk on device without the development server?

There are two extensions you can use for this. This is added to react-native for setting these:

  1. disableDevInDebug: true: Disables dev server in debug buildType
  2. bundleInDebug: true: Adds jsbundle to debug buildType.

So, your final project.ext.react in android/app/build.gradle should look like below

project.ext.react = [
    enableHermes: false,  // clean and rebuild if changing
    devDisabledInDev: true, // Disable dev server in dev release
    bundleInDev: true, // add bundle to dev apk
]

sending email via php mail function goes to spam

Try changing your headers to this:

$headers = "MIME-Version: 1.0" . "\r\n";
$headers .= "Content-type: text/html; charset=iso-8859-1" . "\r\n";
$headers .= "From: [email protected]" . "\r\n" .
"Reply-To: [email protected]" . "\r\n" .
"X-Mailer: PHP/" . phpversion();

For a few reasons.

  • One of which is the need of a Reply-To and,

  • The use of apostrophes instead of double-quotes. Those two things in my experience with forms, is usually what triggers a message ending up in the Spam box.

You could also try changing the $from to:

$from = "[email protected]";


EDIT:

See these links I found on the subject https://stackoverflow.com/a/9988544/1415724 and https://stackoverflow.com/a/16717647/1415724 and https://stackoverflow.com/a/9899837/1415724

https://stackoverflow.com/a/5944155/1415724 and https://stackoverflow.com/a/6532320/1415724

  • Try using the SMTP server of your ISP.

    Using this apparently worked for many: X-MSMail-Priority: High

http://www.webhostingtalk.com/showthread.php?t=931932

"My host helped me to enable DomainKeys and SPF Records on my domain and now when I send a test message to my Hotmail address it doesn't end up in Junk. It was actually really easy to enable these settings in cPanel under Email Authentication. I can't believe I never saw that before. It only works with sending through SMTP using phpmailer by the way. Any other way it still is marked as spam."

PHPmailer sending mail to spam in hotmail. how to fix http://pastebin.com/QdQUrfax

How SQL query result insert in temp table?

Look at SELECT INTO. This will create a new table for you, which can be temporary if you want by prefixing the table name with a pound sign (#).

For example, you can do:

SELECT * 
INTO #YourTempTable
FROM YourReportQuery

Set value of textarea in jQuery

This works:

var t = $('#taCommentSalesAdministration');
t.val('Hi');

Remember, the tricky part here is making sure you use the correct ID. And before you use the ID make sure you put # before it.

Interactive shell using Docker Compose

In the official getting started example (https://docs.docker.com/compose/gettingstarted/) with the following docker-compose.yml:

version: '3'
services:
  web:
    build: .
    ports:
     - "5000:5000"
  redis:
    image: "redis:alpine"

After you start this with docker-compose up, you can easily shell into either your redis container or your web container with:

docker-compose exec redis sh
docker-compose exec web sh 

How do I print colored output with Python 3?

# Pure Python 3.x demo, 256 colors
# Works with bash under Linux and MacOS

fg = lambda text, color: "\33[38;5;" + str(color) + "m" + text + "\33[0m"
bg = lambda text, color: "\33[48;5;" + str(color) + "m" + text + "\33[0m"

def print_six(row, format):
    for col in range(6):
        color = row*6 + col + 4
        if color>=0:
            text = "{:3d}".format(color)
            print (format(text,color), end=" ")
        else:
            print("   ", end=" ")

for row in range(-1,42):
    print_six(row, fg)
    print("",end=" ")
    print_six(row, bg)
    print()

# Simple usage: print(fg("text", 160))

Text with altering foreground and background, colors 0..141 Text with altering foreground and background, colors 142..255

How can I force component to re-render with hooks in React?

For regular React Class based components, refer to React Docs for the forceUpdate api at this URL. The docs mention that:

Normally you should try to avoid all uses of forceUpdate() and only read from this.props and this.state in render()

However, it is also mentioned in the docs that:

If your render() method depends on some other data, you can tell React that the component needs re-rendering by calling forceUpdate().

So, although use cases for using forceUpdate might be rare, and I have not used it ever, however I have seen it used by other developers in some legacy corporate projects that I have worked on.

So, for the equivalent functionality for Functional Components, refer to the React Docs for HOOKS at this URL. Per the above URL, one can use the "useReducer" hook to provide a forceUpdate functionality for Functional Components.

A working code sample that does not use state or props is provided below, which is also available on CodeSandbox at this URL

import React, { useReducer, useRef } from "react";
import ReactDOM from "react-dom";

import "./styles.css";

function App() {
  // Use the useRef hook to store a mutable value inside a functional component for the counter
  let countref = useRef(0);

  const [, forceUpdate] = useReducer(x => x + 1, 0);

  function handleClick() {
    countref.current++;
    console.log("Count = ", countref.current);
    forceUpdate(); // If you comment this out, the date and count in the screen will not be updated
  }

  return (
    <div className="App">
      <h1> {new Date().toLocaleString()} </h1>
      <h2>You clicked {countref.current} times</h2>
      <button
        onClick={() => {
          handleClick();
        }}
      >
        ClickToUpdateDateAndCount
      </button>
    </div>
  );
}

const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);

NOTE: An alternate approach using the useState hook (instead of useReducer) is also available at this URL.

How to style dt and dd so they are on the same line?

I need to do this and have the <dt> content vertically centered, relative to the <dd> content. I used display: inline-block, together with vertical-align: middle

See full example on Codepen here

.dl-horizontal {
  font-size: 0;
  text-align: center;

  dt, dd {
    font-size: 16px;
    display: inline-block;
    vertical-align: middle;
    width: calc(50% - 10px);
  }

  dt {
    text-align: right;
    padding-right: 10px;
  }

  dd {
    font-size: 18px;
    text-align: left;
    padding-left: 10px;
  } 
}

Oracle (ORA-02270) : no matching unique or primary key for this column-list error

Isn't the difference between your declaration of USERID the problem

JOB: UserID is Varchar
USER: UserID is Number?

How to implement the Java comparable interface?

Implement Comparable<Animal> interface in your class and provide implementation of int compareTo(Animal other) method in your class.See This Post

When is the init() function run?

Something to add to this (which I would've added as a comment but the time of writing this post I'd not yet enough reputation)

Having multiple inits in the same package I've not yet found any guaranteed way to know what order in which they will be run. For example I have:

package config
    - config.go
    - router.go

Both config.go and router.go contain init() functions, but when running router.go's function ran first (which caused my app to panic).

If you're in a situation where you have multiple files, each with its own init() function be very aware that you aren't guaranteed to get one before the other. It is better to use a variable assignment as OneToOne shows in his example. Best part is: This variable declaration will happen before ALL init() functions in the package.

For example

config.go:

var ConfigSuccess = configureApplication()

func init() {
    doSomething()
}

func configureApplication() bool {
    l4g.Info("Configuring application...")
    if valid := loadCommandLineFlags(); !valid {
        l4g.Critical("Failed to load Command Line Flags")
        return false
    }
    return true
}

router.go:

func init() {
    var (
        rwd string
        tmp string
        ok  bool
    )
    if metapath, ok := Config["fs"]["metapath"].(string); ok {
        var err error
        Conn, err = services.NewConnection(metapath + "/metadata.db")
        if err != nil {
            panic(err)
        }
    }
}

regardless of whether var ConfigSuccess = configureApplication() exists in router.go or config.go, it will be run before EITHER init() is run.

How to concatenate items in a list to a single string?

If you want to generate a string of strings separated by commas in final result, you can use something like this:

sentence = ['this','is','a','sentence']
sentences_strings = "'" + "','".join(sentence) + "'"
print (sentences_strings) # you will get "'this','is','a','sentence'"

I hope this can help someone.

Xcode 6 Storyboard the wrong size?

Go to Attributes Inspector(right top corner) In the Simulated Metrics, which has Size, Orientation, Status Bar, Top Bar, Bottom Bar properties. For SIZE, change Inferred --> Freeform.

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

Use the quotemeta function:

$text_to_search = "example text with [foo] and more";
$search_string = quotemeta "[foo]";

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

Python Create unix timestamp five minutes in the future

def in_unix(input):
  start = datetime.datetime(year=1970,month=1,day=1)
  diff = input - start
  return diff.total_seconds()

How does a PreparedStatement avoid or prevent SQL injection?

I guess it will be a string. But the input parameters will be sent to the database & appropriate cast/conversions will be applied prior to creating an actual SQL statement.

To give you an example, it might try and see if the CAST/Conversion works.
If it works, it could create a final statement out of it.

   SELECT * From MyTable WHERE param = CAST('10; DROP TABLE Other' AS varchar(30))

Try an example with a SQL statement accepting a numeric parameter.
Now, try passing a string variable (with numeric content that is acceptable as numeric parameter). Does it raise any error?

Now, try passing a string variable (with content that is not acceptable as numeric parameter). See what happens?

Java - How do I make a String array with values?

By using the array initializer list syntax, ie:

String myArray[] = { "one", "two", "three" };

What is the best way to prevent session hijacking?

Protect by:

$ip=$_SERVER['REMOTE_ADDER'];
$_SESSEION['ip']=$ip;

How to get first character of a string in SQL?

It is simple to achieve by the following

DECLARE @SomeString NVARCHAR(20) = 'This is some string'
DECLARE @Result NVARCHAR(20)

Either

SET @Result = SUBSTRING(@SomeString, 2, 3)
SELECT @Result

@Result = his

or

SET @Result = LEFT(@SomeString, 6)
SELECT @Result

@Result = This i

Efficient way to Handle ResultSet in Java

A couple of things to enhance the other answers. First, you should never return a HashMap, which is a specific implementation. Return instead a plain old java.util.Map. But that's actually not right for this example, anyway. Your code only returns the last row of the ResultSet as a (Hash)Map. You instead want to return a List<Map<String,Object>>. Think about how you should modify your code to do that. (Or you could take Dave Newton's suggestion).

How can I build multiple submit buttons django form?

You can also do like this,

 <form method='POST'>
    {{form1.as_p}}
    <button type="submit" name="btnform1">Save Changes</button>
    </form>
    <form method='POST'>
    {{form2.as_p}}
    <button type="submit" name="btnform2">Save Changes</button>
    </form>

CODE

if request.method=='POST' and 'btnform1' in request.POST:
    do something...
if request.method=='POST' and 'btnform2' in request.POST:
    do something...

How to restart a node.js server

If it's just running (not a daemon) then just use Ctrl-C.

If it's daemonized then you could try:

$ ps aux | grep node
you   PID  1.5  0.2  44172  8260 pts/2    S    15:25   0:00 node app.js
$ kill -2 PID

Where PID is replaced by the number in the output of ps.

Html.HiddenFor value property not getting set

The following will work in MVC 4

@Html.HiddenFor(x => x.CRN, new { @Value = "1" });

@Value property is case sensitive. You need a capital 'V' on @Value.

Here is my model

public int CRN { get; set; }

Here is what is output in html when you look in the browser

<input value="1" data-val="true" data-val-number="The field CRN must be a number." data-val-required="The CRN field is required." id="CRN" name="CRN" type="hidden" value="1"/>

Here is my method

[HttpPost]
public ActionResult MyMethod(MyViewModel viewModel)
{
  int crn = viewModel.CRN;
}

In PowerShell, how can I test if a variable holds a numeric value?

Each numeric type has its own value. See TypeCode enum definition: https://docs.microsoft.com/en-us/dotnet/api/system.typecode?view=netframework-4.8 Based on this info, all your numeric type-values are in the range from 5 to 15. This means, you can write the condition-check like this:

$typeValue = $x.getTypeCode().value__
if ($typeValue -ge 5 -and $typeValue -le 15) {"x has a numeric type!"}

How to unpackage and repackage a WAR file

no need to that, tomcat naturally extract the war file into a folder of the same name. you simply modify the desired file inside that folder (including .xml configuration files), that's all. technically no need to restart tomcat after applying the modifications

Xcode 5.1 - No architectures to compile for (ONLY_ACTIVE_ARCH=YES, active arch=x86_64, VALID_ARCHS=i386)

To avoid having "pod install" reset only_active_arch for debug each time it's run, you can add the following to your pod file

# Append to your Podfile
post_install do |installer_representation|
    installer_representation.project.targets.each do |target|
        target.build_configurations.each do |config|
            config.build_settings['ONLY_ACTIVE_ARCH'] = 'NO'
        end
    end
end

Transform char array into String

Three years later, I ran into the same problem. Here's my solution, everybody feel free to cut-n-paste. The simplest things keep us up all night! Running on an ATMega, and Adafruit Feather M0:

void setup() {
  // turn on Serial so we can see...
  Serial.begin(9600);

  // the culprit:
  uint8_t my_str[6];    // an array big enough for a 5 character string

  // give it something so we can see what it's doing
  my_str[0] = 'H';
  my_str[1] = 'e';
  my_str[2] = 'l';
  my_str[3] = 'l';
  my_str[4] = 'o';
  my_str[5] = 0;  // be sure to set the null terminator!!!

  // can we see it?
  Serial.println((char*)my_str);

  // can we do logical operations with it as-is?
  Serial.println((char*)my_str == 'Hello');

  // okay, it can't; wrong data type (and no terminator!), so let's do this:
  String str((char*)my_str);

  // can we see it now?
  Serial.println(str);

  // make comparisons
  Serial.println(str == 'Hello');

  // one more time just because
  Serial.println(str == "Hello");

  // one last thing...!
  Serial.println(sizeof(str));
}

void loop() {
  // nothing
}

And we get:

Hello    // as expected
0        // no surprise; wrong data type and no terminator in comparison value
Hello    // also, as expected
1        // YAY!
1        // YAY!
6        // as expected

Hope this helps someone!

How to convert a boolean array to an int array

Using numpy, you can do:

y = x.astype(int)

If you were using a non-numpy array, you could use a list comprehension:

y = [int(val) for val in x]

Error: Cannot find module html

Use

res.sendFile()

instead of

res.render().

What your trying to do is send a whole file.

This worked for me.

What is Parse/parsing?

From dictionary.reference.com:

Computers. to analyze (a string of characters) in order to associate groups of characters with the syntactic units of the underlying grammar.

The context of the definition is the translation of program text or a language in the general sense into its component parts with respect to a defined grammar -- turning program text into code. In the context of a particular language keyword, though, it generally means to convert the string value of a fundamental data type into an internal representation of that data type. For example, the string "10" becomes the number (integer) 10.

What is the use of GO in SQL Server Management Studio & Transact SQL?

Just to add to the existing answers, when you are creating views you must separate these commands into batches using go, otherwise you will get the error 'CREATE VIEW' must be the only statement in the batch. So, for example, you won't be able to execute the following sql script without go

create view MyView1 as
select Id,Name from table1
go
create view MyView2 as
select Id,Name from table1
go

select * from MyView1
select * from MyView2

What are the benefits to marking a field as `readonly` in C#?

Don't forget there is a workaround to get the readonly fields set outside of any constructors using out params.

A little messy but:

private readonly int _someNumber;
private readonly string _someText;

public MyClass(int someNumber) : this(data, null)
{ }

public MyClass(int someNumber, string someText)
{
    Initialise(out _someNumber, someNumber, out _someText, someText);
}

private void Initialise(out int _someNumber, int someNumber, out string _someText, string someText)
{
    //some logic
}

Further discussion here: http://www.adamjamesnaylor.com/2013/01/23/Setting-Readonly-Fields-From-Chained-Constructors.aspx

What is an NP-complete in computer science?

NP stands for Non-deterministic Polynomial time.

This means that the problem can be solved in Polynomial time using a Non-deterministic Turing machine (like a regular Turing machine but also including a non-deterministic "choice" function). Basically, a solution has to be testable in poly time. If that's the case, and a known NP problem can be solved using the given problem with modified input (an NP problem can be reduced to the given problem) then the problem is NP complete.

The main thing to take away from an NP-complete problem is that it cannot be solved in polynomial time in any known way. NP-Hard/NP-Complete is a way of showing that certain classes of problems are not solvable in realistic time.

Edit: As others have noted, there are often approximate solutions for NP-Complete problems. In this case, the approximate solution usually gives an approximation bound using special notation which tells us how close the approximation is.

Failed to add a service. Service metadata may not be accessible. Make sure your service is running and exposing metadata.`

FYI - YOU CAN also get this error from a machine that is not having enough memory free. I got this error on a machine I run with 16 gigs of memory. I had a VM running with 6 gigs and a LOT of memory intensive apps. Close some down and this problem went away.

I still did get the error in the title of the question of

Failed to add a service. Service metadata may not be accessible. Make sure your service is running and exposing metadata.`

I did notice a larger message about memory though in using the WCF Test Client.

Hope this helps someone else.

What's the best way to validate an XML file against an XSD file?

If you are generating XML files programatically, you may want to look at the XMLBeans library. Using a command line tool, XMLBeans will automatically generate and package up a set of Java objects based on an XSD. You can then use these objects to build an XML document based on this schema.

It has built-in support for schema validation, and can convert Java objects to an XML document and vice-versa.

Castor and JAXB are other Java libraries that serve a similar purpose to XMLBeans.

phpMyAdmin - Error > Incorrect format parameter?

This error is caused by the fact that the maximum upload size is (Max: 2,048KiB). If your file is bigger than this, you will get an error. Zip the file and upload it again, you will not get the error.

Radio buttons not checked in jQuery

if ( ! $("input").is(':checked') )

Doesn't work?

You might also try iterating over the elements like so:

var iz_checked = true;
$('input').each(function(){
   iz_checked = iz_checked && $(this).is(':checked');
});
if ( ! iz_checked )

Browser: Identifier X has already been declared

But I have declared that var in the top of the other files.

That's the problem. After all, this makes multiple declarations for the same name in the same (global) scope - which will throw an error with const.

Instead, use var, use only one declaration in your main file, or only assign to window.APP exclusively.
Or use ES6 modules right away, and let your module bundler/loader deal with exposing them as expected.

How to resize html canvas element?

You didn't publish your code, and I suspect you do something wrong. it is possible to change the size by assigning width and height attributes using numbers:

canvasNode.width  = 200; // in pixels
canvasNode.height = 100; // in pixels

At least it works for me. Make sure you don't assign strings (e.g., "2cm", "3in", or "2.5px"), and don't mess with styles.

Actually this is a publicly available knowledge — you can read all about it in the HTML canvas spec — it is very small and unusually informative. This is the whole DOM interface:

interface HTMLCanvasElement : HTMLElement {
           attribute unsigned long width;
           attribute unsigned long height;

  DOMString toDataURL();
  DOMString toDataURL(in DOMString type, [Variadic] in any args);

  DOMObject getContext(in DOMString contextId);
};

As you can see it defines 2 attributes width and height, and both of them are unsigned long.

Python threading. How do I lock a thread?

You can see that your locks are pretty much working as you are using them, if you slow down the process and make them block a bit more. You had the right idea, where you surround critical pieces of code with the lock. Here is a small adjustment to your example to show you how each waits on the other to release the lock.

import threading
import time
import inspect

class Thread(threading.Thread):
    def __init__(self, t, *args):
        threading.Thread.__init__(self, target=t, args=args)
        self.start()

count = 0
lock = threading.Lock()

def incre():
    global count
    caller = inspect.getouterframes(inspect.currentframe())[1][3]
    print "Inside %s()" % caller
    print "Acquiring lock"
    with lock:
        print "Lock Acquired"
        count += 1  
        time.sleep(2)  

def bye():
    while count < 5:
        incre()

def hello_there():
    while count < 5:
        incre()

def main():    
    hello = Thread(hello_there)
    goodbye = Thread(bye)


if __name__ == '__main__':
    main()

Sample output:

...
Inside hello_there()
Acquiring lock
Lock Acquired
Inside bye()
Acquiring lock
Lock Acquired
...

Structure of a PDF file?

Here's the raw reference of PDF 1.7, and here's an article describing the structure of a PDF file. If you use Vim, the pdftk plugin is a good way to explore the document in an ever-so-slightly less raw form, and the pdftk utility itself (and its GPL source) is a great way to tease documents apart.

Correct use for angular-translate in controllers

Actually, you should use the translate directive for such stuff instead.

<h1 translate="{{pageTitle}}"></h1>

The directive takes care of asynchronous execution and is also clever enough to unwatch translation ids on the scope if the translation has no dynamic values.

However, if there's no way around and you really have to use $translate service in the controller, you should wrap the call in a $translateChangeSuccess event using $rootScope in combination with $translate.instant() like this:

.controller('foo', function ($rootScope, $scope, $translate) {
  $rootScope.$on('$translateChangeSuccess', function () {
    $scope.pageTitle = $translate.instant('PAGE.TITLE');
  });
})

So why $rootScope and not $scope? The reason for that is, that in angular-translate's events are $emited on $rootScope rather than $broadcasted on $scope because we don't need to broadcast through the entire scope hierarchy.

Why $translate.instant() and not just async $translate()? When $translateChangeSuccess event is fired, it is sure that the needed translation data is there and no asynchronous execution is happening (for example asynchronous loader execution), therefore we can just use $translate.instant() which is synchronous and just assumes that translations are available.

Since version 2.8.0 there is also $translate.onReady(), which returns a promise that is resolved as soon as translations are ready. See the changelog.

C# - Substring: index and length must refer to a location within the string

string newString = url.Substring(18, (url.LastIndexOf(".") - 18))

Keyboard shortcuts in WPF

One way is to add your shortcut keys to the commands themselves them as InputGestures. Commands are implemented as RoutedCommands.

This enables the shortcut keys to work even if they're not hooked up to any controls. And since menu items understand keyboard gestures, they'll automatically display your shortcut key in the menu items text, if you hook that command up to your menu item.

  1. Create static attribute to hold a command (preferably as a property in a static class you create for commands - but for a simple example, just using a static attribute in window.cs):

     public static RoutedCommand MyCommand = new RoutedCommand();
    
  2. Add the shortcut key(s) that should invoke method:

     MyCommand.InputGestures.Add(new KeyGesture(Key.S, ModifierKeys.Control));
    
  3. Create a command binding that points to your method to call on execute. Put these in the command bindings for the UI element under which it should work for (e.g., the window) and the method:

     <Window.CommandBindings>
         <CommandBinding Command="{x:Static local:MyWindow.MyCommand}" Executed="MyCommandExecuted"/>
     </Window.CommandBindings>
    
     private void MyCommandExecuted(object sender, ExecutedRoutedEventArgs e) { ... }
    

Getting a machine's external IP address with Python

The most simple (non python) working solution I can think of is

wget -q -O- icanhazip.com

I'd like to add a very short Python3 solution which makes use of the JSON API of http://hostip.info.

from urllib.request import urlopen
import json
url = 'http://api.hostip.info/get_json.php'
info = json.loads(urlopen(url).read().decode('utf-8'))
print(info['ip'])

You can of course add some error checking, a timeout condition and some convenience:

#!/usr/bin/env python3
from urllib.request import urlopen
from urllib.error import URLError
import json

try:
    url = 'http://api.hostip.info/get_json.php'
    info = json.loads(urlopen(url, timeout = 15).read().decode('utf-8'))
    print(info['ip'])
except URLError as e:
    print(e.reason, end=' ') # e.g. 'timed out'
    print('(are you connected to the internet?)')
except KeyboardInterrupt:
    pass

Update Git submodule to latest commit on origin

It seems like two different scenarios are being mixed together in this discussion:

Scenario 1

Using my parent repository's pointers to submodules, I want to check out the commit in each submodule that the parent repository is pointing to, possibly after first iterating through all submodules and updating/pulling these from remote.

This is, as pointed out, done with

git submodule foreach git pull origin BRANCH
git submodule update

Scenario 2, which I think is what OP is aiming at

New stuff has happened in one or more submodules, and I want to 1) pull these changes and 2) update the parent repository to point to the HEAD (latest) commit of this/these submodules.

This would be done by

git submodule foreach git pull origin BRANCH
git add module_1_name
git add module_2_name
......
git add module_n_name
git push origin BRANCH

Not very practical, since you would have to hardcode n paths to all n submodules in e.g. a script to update the parent repository's commit pointers.

It would be cool to have an automated iteration through each submodule, updating the parent repository pointer (using git add) to point to the head of the submodule(s).

For this, I made this small Bash script:

git-update-submodules.sh

#!/bin/bash

APP_PATH=$1
shift

if [ -z $APP_PATH ]; then
  echo "Missing 1st argument: should be path to folder of a git repo";
  exit 1;
fi

BRANCH=$1
shift

if [ -z $BRANCH ]; then
  echo "Missing 2nd argument (branch name)";
  exit 1;
fi

echo "Working in: $APP_PATH"
cd $APP_PATH

git checkout $BRANCH && git pull --ff origin $BRANCH

git submodule sync
git submodule init
git submodule update
git submodule foreach "(git checkout $BRANCH && git pull --ff origin $BRANCH && git push origin $BRANCH) || true"

for i in $(git submodule foreach --quiet 'echo $path')
do
  echo "Adding $i to root repo"
  git add "$i"
done

git commit -m "Updated $BRANCH branch of deployment repo to point to latest head of submodules"
git push origin $BRANCH

To run it, execute

git-update-submodules.sh /path/to/base/repo BRANCH_NAME

Elaboration

First of all, I assume that the branch with name $BRANCH (second argument) exists in all repositories. Feel free to make this even more complex.

The first couple of sections is some checking that the arguments are there. Then I pull the parent repository's latest stuff (I prefer to use --ff (fast-forwarding) whenever I'm just doing pulls. I have rebase off, BTW).

git checkout $BRANCH && git pull --ff origin $BRANCH

Then some submodule initializing, might be necessary, if new submodules have been added or are not initialized yet:

git submodule sync
git submodule init
git submodule update

Then I update/pull all submodules:

git submodule foreach "(git checkout $BRANCH && git pull --ff origin $BRANCH && git push origin $BRANCH) || true"

Notice a few things: First of all, I'm chaining some Git commands using && - meaning previous command must execute without error.

After a possible successful pull (if new stuff was found on the remote), I do a push to ensure that a possible merge-commit is not left behind on the client. Again, it only happens if a pull actually brought in new stuff.

Finally, the final || true is ensuring that script continues on errors. To make this work, everything in the iteration must be wrapped in the double-quotes and the Git commands are wrapped in parentheses (operator precedence).

My favourite part:

for i in $(git submodule foreach --quiet 'echo $path')
do
  echo "Adding $i to root repo"
  git add "$i"
done

Iterate all submodules - with --quiet, which removes the 'Entering MODULE_PATH' output. Using 'echo $path' (must be in single-quotes), the path to the submodule gets written to output.

This list of relative submodule paths is captured in an array ($(...)) - finally iterate this and do git add $i to update the parent repository.

Finally, a commit with some message explaining that the parent repository was updated. This commit will be ignored by default, if nothing was done. Push this to origin, and you're done.

I have a script running this in a Jenkins job that chains to a scheduled automated deployment afterwards, and it works like a charm.

I hope this will be of help to someone.

Getting A File's Mime Type In Java

public String getFileContentType(String fileName) {
    String fileType = "Undetermined";
    final File file = new File(fileName);
    try
    {
        fileType = Files.probeContentType(file.toPath());
    }
    catch (IOException ioException)
    {
        System.out.println(
                "ERROR: Unable to determine file type for " + fileName
                        + " due to exception " + ioException);
    }
    return fileType;
}

Defining a percentage width for a LinearLayout?

Hope this can help

<LinearLayout android:layout_width="fill_parent"
    android:layout_height="fill_parent" android:orientation="horizontal">

    <LinearLayout android:layout_width="0dip"
        android:layout_height="wrap_content" android:orientation="horizontal"
        android:id="@+id/linearLayout_dummy1" android:layout_weight=".15">
    </LinearLayout>


    <LinearLayout android:layout_height="wrap_content"
        android:id="@+id/linearLayout1" android:orientation="vertical"
        android:layout_width="0dip" android:layout_weight=".7">
        <Button android:text="Button" android:id="@+id/button1"
            android:layout_width="wrap_content" android:layout_height="wrap_content"
            android:layout_gravity="center">
        </Button>
        <Button android:layout_width="wrap_content" android:id="@+id/button2"
            android:layout_height="wrap_content" android:text="Button"
            android:layout_gravity="center"></Button>
        <Button android:layout_width="wrap_content" android:id="@+id/button3"
            android:layout_height="wrap_content" android:text="Button"
            android:layout_gravity="center"></Button>
    </LinearLayout>

    <LinearLayout android:layout_width="0dip"
        android:layout_height="wrap_content" android:orientation="horizontal"
        android:id="@+id/linearLayout_dummy2" android:layout_weight=".15">
    </LinearLayout>

</LinearLayout>

(1) Set layout_width to "0dip" (2) Set the layout_height to .xx (% you want)

Preventing an image from being draggable or selectable without using JS

I created a div element which has the same size as the image and is positioned on top of the image. Then, the mouse events do not go to the image element.

Angular js init ng-model from default values

I tried what @Mark Rajcok suggested. Its working for String values (Visa-4242). Please refer this fiddle.

From the fiddle:

The same thing that is done in the fiddle can be done using ng-repeat, which everybody could recommend. But after reading the answer given by @Mark Rajcok, i just wanted to try the same for a form with array of profiles. Things work well untill i have the $scope.profiles = [{},{}]; code in the controller. If i remove this code, im getting errors. But in normal scenarios i cant print $scope.profiles = [{},{}]; as i print or echo html from the server. Will it be possible to execute the above, in a similar fashion as @Mark Rajcok did for the string values like <input name="card[description]" ng-model="card.description" ng-init="card.description='Visa-4242'">, without having to echo the JavaScript part from the server.

(Mac) -bash: __git_ps1: command not found

__git_ps1 for bash is now found in git-prompt.sh in /usr/local/etc/bash_completion.d on my brew installed git version 1.8.1.5

How to set shadows in React Native for android?

I had the same problem shadow/elevation not showing on Android with elevation:2. Then i noticed that the view element is fool width, so I added margin:2 to the view element and elevation properly appeared.

Style:

    margin: 2,
    shadowColor: '#000',
    shadowOffset: {
      width: 0,
      height: 1
    },
    shadowOpacity: 0.2,
    shadowRadius: 1.41,
    elevation: 2

Android: enter image description here

iOS: enter image description here

How do I add space between items in an ASP.NET RadioButtonList

Use css to add a right margin to those particular elements. Generally I would build the control, then run it to see what the resulting html structure is like, then make the css alter just those elements.

Preferably you do this by setting the class. Add the CssClass="myrblclass" attribute to your list declaration.

You can also add attributes to the items programmatically, which will come out the other side.

rblMyRadioButtonList.Items[x].Attributes.CssStyle.Add("margin-right:5px;")

This may be better for you since you can add that attribute for all but the last one.

Sending HTML mail using a shell script

First you need to compose the message. The bare minimum is composed of these two headers:

MIME-Version: 1.0
Content-Type: text/html

... and the appropriate message body:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head><title></title>
</head>
<body>

<p>Hello, world!</p>

</body>
</html>

Once you have it, you can pass the appropriate information to the mail command:

body = '...'

echo $body | mail \
-a "From: [email protected]" \
-a "MIME-Version: 1.0" \
-a "Content-Type: text/html" \
-s "This is the subject" \
[email protected]

This is an oversimplified example, since you also need to take care of charsets, encodings, maximum line length... But this is basically the idea.

Alternatively, you can write your script in Perl or PHP rather than plain shell.

Update

A shell script is basically a text file with Unix line endings that starts with a line called shebang that tells the shell what interpreter it must pass the file to, follow some commands in the language the interpreter understands and has execution permission (in Unix that's a file attribute). E.g., let's say you save the following as hello-world:

#!/bin/sh

echo Hello, world!

Then you assign execution permission:

chmod +x hello-world

And you can finally run it:

./hello-world

Whatever, this is kind of unrelated to the original question. You should get familiar with basic shell scripting before doing advanced tasks with it. Here you are a couple of links about bash, a popular shell:

http://www.gnu.org/software/bash/manual/html_node/index.html

http://tldp.org/HOWTO/Bash-Prog-Intro-HOWTO.html

recursion versus iteration

recursion + memorization could lead to a more efficient solution compare with a pure iterative approach, e.g. check this: http://jsperf.com/fibonacci-memoized-vs-iterative-for-large-n

jQuery - Follow the cursor with a DIV

You can't follow the cursor with a DIV, but you can draw a DIV when moving the cursor!

$(document).on('mousemove', function(e){
    $('#your_div_id').css({
       left:  e.pageX,
       top:   e.pageY
    });
});

That div must be off the float, so position: absolute should be set.

XMLHttpRequest module not defined/found

Since the last update of the xmlhttprequest module was around 2 years ago, in some cases it does not work as expected.

So instead, you can use the xhr2 module. In other words:

var XMLHttpRequest = require("xmlhttprequest").XMLHttpRequest;
var xhr = new XMLHttpRequest();

becomes:

var XMLHttpRequest = require('xhr2');
var xhr = new XMLHttpRequest();

But ... of course, there are more popular modules like Axios, because -for example- uses promises:

// Make a request for a user with a given ID
axios.get('/user?ID=12345').then(function (response) {
    console.log(response);
}).catch(function (error) {
    console.log(error);
});

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

If none of the other answers are satisfactory, you could always just create an empty row and style it with CSS appropriately to be transparent.

Simplest way to form a union of two lists

I think this is all you really need to do:

var listB = new List<int>{3, 4, 5};
var listA = new List<int>{1, 2, 3, 4, 5};

var listMerged = listA.Union(listB);

Access: Move to next record until EOF

Set rs = me.RecordsetClone
rs.Bookmark = me.Bookmark
Do
    rs.movenext
Loop until rs.eof

Detect rotation of Android phone in the browser with JavaScript

Worth noting that on my Epic 4G Touch I had to set up the webview to use WebChromeClient before any of the javascript android calls worked.

webView.setWebChromeClient(new WebChromeClient());

Check if two unordered lists are equal

One liner answer to the above question is :-

let the two lists be list1 and list2, and your requirement is to ensure whether two lists have the same elements, then as per me, following will be the best approach :-

if ((len(list1) == len(list2)) and
   (all(i in list2 for i in list1))):
    print 'True'
else:
    print 'False'

The above piece of code will work per your need i.e. whether all the elements of list1 are in list2 and vice-verse.

But if you want to just check whether all elements of list1 are present in list2 or not, then you need to use the below code piece only :-

if all(i in list2 for i in list1):
    print 'True'
else:
    print 'False'

The difference is, the later will print True, if list2 contains some extra elements along with all the elements of list1. In simple words, it will ensure that all the elements of list1 should be present in list2, regardless of whether list2 has some extra elements or not.

how to set background image in submit button?

i do it like this cover button and the middle image that

<button><img src="foldername/imagename" width="30px" height= "30px"></button>

How to use "Share image using" sharing Intent to share images in android?

I found the easiest way to do this is by using the MediaStore to temporarily store the image that you want to share:

Drawable mDrawable = mImageView.getDrawable();
Bitmap mBitmap = ((BitmapDrawable) mDrawable).getBitmap();

String path = MediaStore.Images.Media.insertImage(getContentResolver(), mBitmap, "Image Description", null);
Uri uri = Uri.parse(path);

Intent intent = new Intent(Intent.ACTION_SEND);
intent.setType("image/jpeg");
intent.putExtra(Intent.EXTRA_STREAM, uri);
startActivity(Intent.createChooser(intent, "Share Image"));

From: Sharing Content With Intents

How to check if a list is empty in Python?

I like Zarembisty's answer. Although, if you want to be more explicit, you can always do:

if len(my_list) == 0:
    print "my_list is empty"

How can I get file extensions with JavaScript?

function file_get_ext(filename)
    {
    return typeof filename != "undefined" ? filename.substring(filename.lastIndexOf(".")+1, filename.length).toLowerCase() : false;
    }

HTTP Content-Type Header and JSON

The Content-Type header is just used as info for your application. The browser doesn't care what it is. The browser just returns you the data from the AJAX call. If you want to parse it as JSON, you need to do that on your own.

The header is there so your app can detect what data was returned and how it should handle it. You need to look at the header, and if it's application/json then parse it as JSON.

This is actually how jQuery works. If you don't tell it what to do with the result, it uses the Content-Type to detect what to do with it.

SQL Server: use CASE with LIKE

SELECT Lname, Cods, CASE WHEN Lname LIKE '% HN%' THEN SUBSTRING(Lname, 
CHARINDEX(' ', Lname) - 50, 50) WHEN Lname LIKE 'HN%' THEN Lname ELSE 
Lname END AS LnameTrue FROM dbo.____Fname_Lname

Git: Merge a Remote branch locally

Maybe you want to track the remote branch with a local branch:

  1. Create a new local branch: git branch new-local-branch
  2. Set this newly created branch to track the remote branch: git branch --set-upstream-to=origin/remote-branch new-local-branch
  3. Enter into this branch: git checkout new-local-branch
  4. Pull all the contents of the remote branch into the local branch: git pull

Format Date time in AngularJS

I know this is an old item, but thought I'd throw in another option to consider.

As the original string doesn't include the "T" demarker, the default implementation in Angular doesn't recognize it as a date. You can force it using new Date, but that is a bit of a pain on an array. Since you can pipe filters together, you might be able to use a filter to convert your input to a date and then apply the date: filter on the converted date. Create a new custom filter as follows:

app
.filter("asDate", function () {
    return function (input) {
        return new Date(input);
    }
});

Then in your markup, you can pipe the filters together:

{{item.myDateTimeString | asDate | date:'shortDate'}}

Merge two HTML table cells

Set the colspan attribute to 2.

...but please don't use tables for layout.

Cannot find JavaScriptSerializer in .Net 4.0

For those who seem to be following the answers above but still have the problem (e.g., see the first comment on the poster's question):

You are probably working in a solution with many projects. The project you appear to be working in references other projects, but you are actually modifying a file from one of the other projects. For example:

  • project A references System.Web.Extensions
  • project A references project B

But if the file you are modifying to use System.Web.Script.Serialization is in project B, then you will need to add a reference to System.Web.Extension in project B as well.

What's the point of 'meta viewport user-scalable=no' in the Google Maps API

Disabling user-scalable (namely, the ability to double tap to zoom) allows the browser to reduce the click delay. In touch-enable browsers, when the user expects the double tap to zoom, the browser generally waits 300ms before firing the click event, waiting to see if the user will double tap. Disabling user-scalable allows for the Chrome browser to fire the click event immediately, allowing for a better user experience.

From Google IO 2013 session https://www.youtube.com/watch?feature=player_embedded&v=DujfpXOKUp8#t=1435s

Update: its not true anymore, <meta name="viewport" content="width=device-width"> is enough to remove 300ms delay

HTML table sort

Here is another library.

Changes required are -

  1. Add sorttable js

  2. Add class name sortable to table.

Click the table headers to sort the table accordingly:

_x000D_
_x000D_
<script src="https://www.kryogenix.org/code/browser/sorttable/sorttable.js"></script>

<table class="sortable">
  <tr>
    <th>Name</th>
    <th>Address</th>
    <th>Sales Person</th>
  </tr>

  <tr class="item">
    <td>user:0001</td>
    <td>UK</td>
    <td>Melissa</td>
  </tr>
  <tr class="item">
    <td>user:0002</td>
    <td>France</td>
    <td>Justin</td>
  </tr>
  <tr class="item">
    <td>user:0003</td>
    <td>San Francisco</td>
    <td>Judy</td>
  </tr>
  <tr class="item">
    <td>user:0004</td>
    <td>Canada</td>
    <td>Skipper</td>
  </tr>
  <tr class="item">
    <td>user:0005</td>
    <td>Christchurch</td>
    <td>Alex</td>
  </tr>

</table>
_x000D_
_x000D_
_x000D_

convert epoch time to date

EDIT: Okay, so you don't want your local time (which isn't Australia) to contribute to the result, but instead the Australian time zone. Your existing code should be absolutely fine then, although Sydney is currently UTC+11, not UTC+10.. Short but complete test app:

import java.util.*;
import java.text.*;

public class Test {
    public static void main(String[] args) throws InterruptedException {
        Date date = new Date(1318386508000L);
        DateFormat format = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss");
        format.setTimeZone(TimeZone.getTimeZone("Etc/UTC"));
        String formatted = format.format(date);
        System.out.println(formatted);
        format.setTimeZone(TimeZone.getTimeZone("Australia/Sydney"));
        formatted = format.format(date);
        System.out.println(formatted);
    }
}

Output:

12/10/2011 02:28:28
12/10/2011 13:28:28

I would also suggest you start using Joda Time which is simply a much nicer date/time API...

EDIT: Note that if your system doesn't know about the Australia/Sydney time zone, it would show UTC. For example, if I change the code about to use TimeZone.getTimeZone("blah/blah") it will show the UTC value twice. I suggest you print TimeZone.getTimeZone("Australia/Sydney").getDisplayName() and see what it says... and check your code for typos too :)

jQuery get selected option value (not the text, but the attribute 'value')

Try this:

$(document).ready(function(){
    var data= $('select').find('option:selected').val();
});

or

var data= $('select').find('option:selected').text();

Remove trailing newline from the elements of a string list

my_list = ['this\n', 'is\n', 'a\n', 'list\n', 'of\n', 'words\n']
print([l.strip() for l in my_list])

Output:

['this', 'is', 'a', 'list', 'of', 'words']

Generating random, unique values C#

You could also use a dataTable storing each random value, then simply perform the random method while != values in the dataColumn

What does the exclamation mark do before the function?

JavaScript syntax 101. Here is a function declaration:

function foo() {}

Note that there's no semicolon: this is just a function declaration. You would need an invocation, foo(), to actually run the function.

Now, when we add the seemingly innocuous exclamation mark: !function foo() {} it turns it into an expression. It is now a function expression.

The ! alone doesn't invoke the function, of course, but we can now put () at the end: !function foo() {}() which has higher precedence than ! and instantly calls the function.

So what the author is doing is saving a byte per function expression; a more readable way of writing it would be this:

(function(){})();

Lastly, ! makes the expression return true. This is because by default all immediately invoked function expressions (IIFE) return undefined, which leaves us with !undefined which is true. Not particularly useful.

How to show a GUI message box from a bash script in linux?

There is also dialog and the KDE version kdialog. dialog is used by slackware, so it might not be immediately available on other distributions.

How can I access iframe elements with Javascript?

If you have the HTML

<form name="formname" .... id="form-first">
    <iframe id="one" src="iframe2.html">
    </iframe>
</form>

and JavaScript

function iframeRef( frameRef ) {
    return frameRef.contentWindow
        ? frameRef.contentWindow.document
        : frameRef.contentDocument
}

var inside = iframeRef( document.getElementById('one') )

inside is now a reference to the document, so you can do getElementsByTagName('textarea') and whatever you like, depending on what's inside the iframe src.

XAMPP Start automatically on Windows 7 startup

I just placed a short-cut to the XAMPP control panel in my startup folder. That works just fine on Window 7. Start -> All Programs -> Startup. There is also an option to start XAMPP control panel minimized, that is very useful for getting a clean unobstructed view of your desktop at start-up.**

Set and Get Methods in java?

this is the code for set method

public void setAge(int age){
  this.age = age;
}

Case insensitive 'in'

You could do

matcher = re.compile('MICHAEL89', re.IGNORECASE)
filter(matcher.match, USERNAMES) 

Update: played around a bit and am thinking you could get a better short-circuit type approach using

matcher = re.compile('MICHAEL89', re.IGNORECASE)
if any( ifilter( matcher.match, USERNAMES ) ):
    #your code here

The ifilter function is from itertools, one of my favorite modules within Python. It's faster than a generator but only creates the next item of the list when called upon.

Programmatically go back to previous ViewController in Swift

swift 5 and above

case 1 : using with Navigation controller

self.navigationController?.popViewController(animated: true)

case 2 : using with present view controller

self.dismiss(animated: true, completion: nil)

What does the explicit keyword mean?

Suppose, you have a class String:

class String {
public:
    String(int n); // allocate n bytes to the String object
    String(const char *p); // initializes object with char *p
};

Now, if you try:

String mystring = 'x';

The character 'x' will be implicitly converted to int and then the String(int) constructor will be called. But, this is not what the user might have intended. So, to prevent such conditions, we shall define the constructor as explicit:

class String {
public:
    explicit String (int n); //allocate n bytes
    String(const char *p); // initialize sobject with string p
};

In a Git repository, how to properly rename a directory?

If you receive this error: fatal: renaming ‘foldername’ failed: Invalid argument

Try this:

*nixOS

git mv foldername tempname && git mv tempname folderName

WinOS

git config core.ignorecase false; git mv foldername tempname; git mv tempname folderName

Oracle PL/SQL : remove "space characters" from a string

Since you're comfortable with regular expressions, you probably want to use the REGEXP_REPLACE function. If you want to eliminate anything that matches the [:space:] POSIX class

REGEXP_REPLACE( my_value, '[[:space:]]', '' )


SQL> ed
Wrote file afiedt.buf

  1  select '|' ||
  2         regexp_replace( 'foo ' || chr(9), '[[:space:]]', '' ) ||
  3         '|'
  4*   from dual
SQL> /

'|'||
-----
|foo|

If you want to leave one space in place for every set of continuous space characters, just add the + to the regular expression and use a space as the replacement character.

with x as (
  select 'abc 123  234     5' str
    from dual
)
select regexp_replace( str, '[[:space:]]+', ' ' )
  from x

How can I create a carriage return in my C# string

Along with Environment.NewLine and the literal \r\n or just \n you may also use a verbatim string in C#. These begin with @ and can have embedded newlines. The only thing to keep in mind is that " needs to be escaped as "". An example:

string s = @"This is a string
that contains embedded new lines,
that will appear when this string is used."

Is there a Java API that can create rich Word documents?

In 2007 my project successfully used OpenOffice.org's Universal Network Objects (UNO) interface to programmatically generate MS-Word compatible documents (*.doc), as well as corresponding PDF documents, from a Java Web application (a Struts/JSP framework).

OpenOffice UNO also lets you build MS-Office-compatible charts, spreadsheets, presentations, etc. We were able to dynamically build sophisticated Word documents, including charts and tables.

We simplified the process by using template MS-Word documents with bookmark inserts into which the software inserted content, however, you can build documents completely from scratch. The goal was to have the software generate report documents that could be shared and further tweaked by end-users before converting them to PDF for final delivery and archival.

You can optionally produce documents in OpenOffice formats if you want users to use OpenOffice instead of MS-Office. In our case the users want to use MS-Office tools.

UNO is included within the OpenOffice suite. We simply linked our Java app to UNO-related libraries within the suite. An OpenOffice Software Development Kit (SDK) is available containing example applications and the UNO Developer's Guide.

I have not investigated whether the latest OpenOffice UNO can generate MS-Office 2007 Open XML document formats.

The important things about OpenOffice UNO are:

  1. It is freeware
  2. It supports multiple languages (e.g. Visual Basic, Java, C++, and others).
  3. It is platform-independent (Windows, Linux, Unix, etc.).

Here are some useful web sites:

DB2 Timestamp select statement

@bhamby is correct. By leaving the microseconds off of your timestamp value, your query would only match on a usagetime of 2012-09-03 08:03:06.000000

If you don't have the complete timestamp value captured from a previous query, you can specify a ranged predicate that will match on any microsecond value for that time:

...WHERE id = 1 AND usagetime BETWEEN '2012-09-03 08:03:06' AND '2012-09-03 08:03:07'

or

...WHERE id = 1 AND usagetime >= '2012-09-03 08:03:06' 
   AND usagetime < '2012-09-03 08:03:07'

How do I get the MAX row with a GROUP BY in LINQ query?

var q = from s in db.Serials
        group s by s.Serial_Number into g
        select new {Serial_Number = g.Key, MaxUid = g.Max(s => s.uid) }

FragmentActivity to Fragment

first of all;

a Fragment must be inside a FragmentActivity, that's the first rule,

a FragmentActivity is quite similar to a standart Activity that you already know, besides having some Fragment oriented methods

second thing about Fragments, is that there is one important method you MUST call, wich is onCreateView, where you inflate your layout, think of it as the setContentLayout

here is an example:

    @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {     mView       = inflater.inflate(R.layout.fragment_layout, container, false);       return mView; } 

and continu your work based on that mView, so to find a View by id, call mView.findViewById(..);


for the FragmentActivity part:

the xml part "must" have a FrameLayout in order to inflate a fragment in it

        <FrameLayout             android:id="@+id/content_frame"             android:layout_width="match_parent"             android:layout_height="match_parent"  >         </FrameLayout> 

as for the inflation part

getSupportFragmentManager().beginTransaction().replace(R.id.content_frame, new YOUR_FRAGMENT, "TAG").commit();


begin with these, as there is tons of other stuf you must know about fragments and fragment activities, start of by reading something about it (like life cycle) at the android developer site

How to check if another instance of my shell script is running

Definitely works.

if [[ `pgrep -f $0` != "$$" ]]; then
        echo "Exiting ! Exist"
        exit
fi

"std::endl" vs "\n"

If you use Qt and endl, you could accidentally end up using an incorrect endl which gives you very surprising results. See the following code snippet:

#include <iostream>
#include <QtCore/QtCore> 
#include <QtGui/QtGui>

// notice that there is no "using namespace std;"
int main(int argc, char** argv)
{
    QApplication qapp(argc,argv);
    QMainWindow mw;
    mw.show();
    std::cout << "Finished Execution!" << endl;
    // This prints something similar to: "Finished Execution!67006AB4"
    return qapp.exec();
}

Note that I wrote endl instead of std::endl (which would have been correct) and apparently there is a endl function defined in qtextstream.h (which is part of QtCore).

Using "\n" instead of endl completely sidesteps any potential namespace issues. This is also a good example why putting symbols into the global namespace (like Qt does by default) is a bad idea.

How to read a text file?

It depends on what you are trying to do.

file, err := os.Open("file.txt")
fmt.print(file)

The reason it outputs &{0xc082016240}, is because you are printing the pointer value of a file-descriptor (*os.File), not file-content. To obtain file-content, you may READ from a file-descriptor.


To read all file content(in bytes) to memory, ioutil.ReadAll

package main

import (
    "fmt"
    "io/ioutil"
    "os"
    "log"
)

func main() {
    file, err := os.Open("file.txt")
    if err != nil {
        log.Fatal(err)
    }
    defer func() {
        if err = f.Close(); err != nil {
            log.Fatal(err)
        }
    }()


  b, err := ioutil.ReadAll(file)
  fmt.Print(b)
}

But sometimes, if the file size is big, it might be more memory-efficient to just read in chunks: buffer-size, hence you could use the implementation of io.Reader.Read from *os.File

func main() {
    file, err := os.Open("file.txt")
    if err != nil {
        log.Fatal(err)
    }
    defer func() {
        if err = f.Close(); err != nil {
            log.Fatal(err)
        }
    }()


    buf := make([]byte, 32*1024) // define your buffer size here.

    for {
        n, err := file.Read(buf)

        if n > 0 {
            fmt.Print(buf[:n]) // your read buffer.
        }

        if err == io.EOF {
            break
        }
        if err != nil {
            log.Printf("read %d bytes: %v", n, err)
            break
        }
    }

}

Otherwise, you could also use the standard util package: bufio, try Scanner. A Scanner reads your file in tokens: separator.

By default, scanner advances the token by newline (of course you can customise how scanner should tokenise your file, learn from here the bufio test).

package main

import (
    "fmt"
    "os"
    "log"
    "bufio"
)

func main() {
    file, err := os.Open("file.txt")
    if err != nil {
        log.Fatal(err)
    }
    defer func() {
        if err = f.Close(); err != nil {
            log.Fatal(err)
        }
    }()

    scanner := bufio.NewScanner(file)

    for scanner.Scan() {             // internally, it advances token based on sperator
        fmt.Println(scanner.Text())  // token in unicode-char
        fmt.Println(scanner.Bytes()) // token in bytes

    }
}

Lastly, I would also like to reference you to this awesome site: go-lang file cheatsheet. It encompassed pretty much everything related to working with files in go-lang, hope you'll find it useful.

What's the best way to store a group of constants that my program uses?

IMO using a class full of constants is fine for constants. If they will change semi-occasionally I recommend using AppSettings in your config and the ConfigurationManager class instead.

When I have "constants" that are actually pulled in from AppSettings or similar I still will always have a "constants" class that wraps the reading from configuration manager. It's always more meaningful to have Constants.SomeModule.Setting instead of having to resort directly to ConfigurationManager.AppSettings["SomeModule/Setting"] on any place that wants to consume said setting value.

Bonus points for this setup, since SomeModule would likely be a nested class inside the Constants file, you could easily use Dependency Injection to inject either SomeModule directly into classes that depend on it. You could also even extract an interface on top of SomeModule and then create a depenedency to ISomeModuleConfiguration in your consuming code, this would then allow you to decouple the dependency to the Constants files, and even potentially make testing easier, especially if these settings come from AppSettings and you change them using config transformations because the settings are environment specific.

When should I use the new keyword in C++?

There is an important difference between the two.

Everything not allocated with new behaves much like value types in C# (and people often say that those objects are allocated on the stack, which is probably the most common/obvious case, but not always true. More precisely, objects allocated without using new have automatic storage duration Everything allocated with new is allocated on the heap, and a pointer to it is returned, exactly like reference types in C#.

Anything allocated on the stack has to have a constant size, determined at compile-time (the compiler has to set the stack pointer correctly, or if the object is a member of another class, it has to adjust the size of that other class). That's why arrays in C# are reference types. They have to be, because with reference types, we can decide at runtime how much memory to ask for. And the same applies here. Only arrays with constant size (a size that can be determined at compile-time) can be allocated with automatic storage duration (on the stack). Dynamically sized arrays have to be allocated on the heap, by calling new.

(And that's where any similarity to C# stops)

Now, anything allocated on the stack has "automatic" storage duration (you can actually declare a variable as auto, but this is the default if no other storage type is specified so the keyword isn't really used in practice, but this is where it comes from)

Automatic storage duration means exactly what it sounds like, the duration of the variable is handled automatically. By contrast, anything allocated on the heap has to be manually deleted by you. Here's an example:

void foo() {
  bar b;
  bar* b2 = new bar();
}

This function creates three values worth considering:

On line 1, it declares a variable b of type bar on the stack (automatic duration).

On line 2, it declares a bar pointer b2 on the stack (automatic duration), and calls new, allocating a bar object on the heap. (dynamic duration)

When the function returns, the following will happen: First, b2 goes out of scope (order of destruction is always opposite of order of construction). But b2 is just a pointer, so nothing happens, the memory it occupies is simply freed. And importantly, the memory it points to (the bar instance on the heap) is NOT touched. Only the pointer is freed, because only the pointer had automatic duration. Second, b goes out of scope, so since it has automatic duration, its destructor is called, and the memory is freed.

And the barinstance on the heap? It's probably still there. No one bothered to delete it, so we've leaked memory.

From this example, we can see that anything with automatic duration is guaranteed to have its destructor called when it goes out of scope. That's useful. But anything allocated on the heap lasts as long as we need it to, and can be dynamically sized, as in the case of arrays. That is also useful. We can use that to manage our memory allocations. What if the Foo class allocated some memory on the heap in its constructor, and deleted that memory in its destructor. Then we could get the best of both worlds, safe memory allocations that are guaranteed to be freed again, but without the limitations of forcing everything to be on the stack.

And that is pretty much exactly how most C++ code works. Look at the standard library's std::vector for example. That is typically allocated on the stack, but can be dynamically sized and resized. And it does this by internally allocating memory on the heap as necessary. The user of the class never sees this, so there's no chance of leaking memory, or forgetting to clean up what you allocated.

This principle is called RAII (Resource Acquisition is Initialization), and it can be extended to any resource that must be acquired and released. (network sockets, files, database connections, synchronization locks). All of them can be acquired in the constructor, and released in the destructor, so you're guaranteed that all resources you acquire will get freed again.

As a general rule, never use new/delete directly from your high level code. Always wrap it in a class that can manage the memory for you, and which will ensure it gets freed again. (Yes, there may be exceptions to this rule. In particular, smart pointers require you to call new directly, and pass the pointer to its constructor, which then takes over and ensures delete is called correctly. But this is still a very important rule of thumb)

Format date as dd/MM/yyyy using pipes

Angular: 8.2.11

<td>{{ data.DateofBirth | date }}</td>

Output: Jun 9, 1973

<td>{{ data.DateofBirth | date: 'dd/MM/yyyy' }}</td>

Output: 09/06/1973

<td>{{ data.DateofBirth | date: 'dd/MM/yyyy hh:mm a' }}</td>

Output: 09/06/1973 12:00 AM

CSS "and" and "or"

The :not pseudo-class is not supported by IE. I'd got for something like this instead:

.registration_form_right input[type="text"],
.registration_form_right input[type="password"],
.registration_form_right input[type="submit"],
.registration_form_right input[type="button"] {
  ...
}

Some duplication there, but it's a small price to pay for higher compatibility.

Is there an advantage to use a Synchronized Method instead of a Synchronized Block?

As already said here synchronized block can use user-defined variable as lock object, when synchronized function uses only "this". And of course you can manipulate with areas of your function which should be synchronized. But everyone says that no difference between synchronized function and block which covers whole function using "this" as lock object. That is not true, difference is in byte code which will be generated in both situations. In case of synchronized block usage should be allocated local variable which holds reference to "this". And as result we will have a little bit larger size for function (not relevant if you have only few number of functions).

More detailed explanation of the difference you can find here: http://www.artima.com/insidejvm/ed2/threadsynchP.html

jQuery Set Cursor Position in Text Area

Set the focus before you have inserted the text into the textarea thus?

$("#comments").focus();
$("#comments").val(comments);

HTML5 Dynamically create Canvas

 <html>
 <head></head>
 <body>
 <canvas id="canvas" width="300" height="300"></canvas>
 <script>
  var sun = new Image();
  var moon = new Image();
  var earth = new Image();
  function init() {
  sun.src = 'https://mdn.mozillademos.org/files/1456/Canvas_sun.png';
  moon.src = 'https://mdn.mozillademos.org/files/1443/Canvas_moon.png';
  earth.src = 'https://mdn.mozillademos.org/files/1429/Canvas_earth.png';
  window.requestAnimationFrame(draw);
  }

  function draw() {
  var ctx = document.getElementById('canvas').getContext('2d');

  ctx.globalCompositeOperation = 'destination-over';
  ctx.clearRect(0, 0, 300, 300);

  ctx.fillStyle = 'rgba(0, 0, 0, 0.4)';
  ctx.strokeStyle = 'rgba(0, 153, 255, 0.4)';
  ctx.save();
  ctx.translate(150, 150);

  // Earth
  var time = new Date();
  ctx.rotate(((2 * Math.PI) / 60) * time.getSeconds() + ((2 * Math.PI) / 60000) * 
  time.getMilliseconds());
  ctx.translate(105, 0);
  ctx.fillRect(10, -19, 55, 31); 
  ctx.drawImage(earth, -12, -12);

   // Moon
  ctx.save();
  ctx.rotate(((2 * Math.PI) / 6) * time.getSeconds() + ((2 * Math.PI) / 6000) * 
  time.getMilliseconds());
  ctx.translate(0, 28.5);
  ctx.drawImage(moon, -3.5, -3.5);
  ctx.restore();

  ctx.restore();

   ctx.beginPath();
   ctx.arc(150, 150, 105, 0, Math.PI * 2, false);
   ctx.stroke();

   ctx.drawImage(sun, 0, 0, 300, 300);

   window.requestAnimationFrame(draw);
    }

   init();
   </script>
   </body>
   </html>

Android: long click on a button -> perform actions

Initially when i implemented a longClick and a click to perform two separate events the problem i face was that when i had a longclick , the application also performed the action to be performed for a simple click . The solution i realized was to change the return type of the longClick to true which is normally false by default . Change it and it works perfectly .

CSS @media print issues with background-color;

-webkit-print-color-adjust: exact; alone is Not enough you have to use !important with the attribute

this is printing preview on chrome after I added !important to each background-color and color attrubute in each tag

printing preview on chrome

and this is printing preview on chrome before adding !important

enter image description here

now, to know how to inject !important to div's style, check out this answer I'm unable to inject a style with an “!important” rule

What's a decent SFTP command-line client for windows?

WinSCP has the command line functionality:

c:\>winscp.exe /console /script=example.txt

where scripting is done in example.txt.

See http://winscp.net/eng/docs/guide_automation

Refer to http://winscp.net/eng/docs/guide_automation_advanced for details on how to use a scripting language such as Windows command interpreter/php/perl.

FileZilla does have a command line but it is limited to only opening the GUI with a pre-defined server that is in the Site Manager.

Switch statement for string matching in JavaScript

Another option is to use input field of a regexp match result:

str = 'XYZ test';
switch (str) {
  case (str.match(/^xyz/) || {}).input:
    console.log("Matched a string that starts with 'xyz'");
    break;
  case (str.match(/test/) || {}).input:
    console.log("Matched the 'test' substring");        
    break;
  default:
    console.log("Didn't match");
    break;
}

What is the difference between .*? and .* regular expressions?

On greedy vs non-greedy

Repetition in regex by default is greedy: they try to match as many reps as possible, and when this doesn't work and they have to backtrack, they try to match one fewer rep at a time, until a match of the whole pattern is found. As a result, when a match finally happens, a greedy repetition would match as many reps as possible.

The ? as a repetition quantifier changes this behavior into non-greedy, also called reluctant (in e.g. Java) (and sometimes "lazy"). In contrast, this repetition will first try to match as few reps as possible, and when this doesn't work and they have to backtrack, they start matching one more rept a time. As a result, when a match finally happens, a reluctant repetition would match as few reps as possible.

References


Example 1: From A to Z

Let's compare these two patterns: A.*Z and A.*?Z.

Given the following input:

eeeAiiZuuuuAoooZeeee

The patterns yield the following matches:

Let's first focus on what A.*Z does. When it matched the first A, the .*, being greedy, first tries to match as many . as possible.

eeeAiiZuuuuAoooZeeee
   \_______________/
    A.* matched, Z can't match

Since the Z doesn't match, the engine backtracks, and .* must then match one fewer .:

eeeAiiZuuuuAoooZeeee
   \______________/
    A.* matched, Z still can't match

This happens a few more times, until finally we come to this:

eeeAiiZuuuuAoooZeeee
   \__________/
    A.* matched, Z can now match

Now Z can match, so the overall pattern matches:

eeeAiiZuuuuAoooZeeee
   \___________/
    A.*Z matched

By contrast, the reluctant repetition in A.*?Z first matches as few . as possible, and then taking more . as necessary. This explains why it finds two matches in the input.

Here's a visual representation of what the two patterns matched:

eeeAiiZuuuuAoooZeeee
   \__/r   \___/r      r = reluctant
    \____g____/        g = greedy

Example: An alternative

In many applications, the two matches in the above input is what is desired, thus a reluctant .*? is used instead of the greedy .* to prevent overmatching. For this particular pattern, however, there is a better alternative, using negated character class.

The pattern A[^Z]*Z also finds the same two matches as the A.*?Z pattern for the above input (as seen on ideone.com). [^Z] is what is called a negated character class: it matches anything but Z.

The main difference between the two patterns is in performance: being more strict, the negated character class can only match one way for a given input. It doesn't matter if you use greedy or reluctant modifier for this pattern. In fact, in some flavors, you can do even better and use what is called possessive quantifier, which doesn't backtrack at all.

References


Example 2: From A to ZZ

This example should be illustrative: it shows how the greedy, reluctant, and negated character class patterns match differently given the same input.

eeAiiZooAuuZZeeeZZfff

These are the matches for the above input:

Here's a visual representation of what they matched:

         ___n
        /   \              n = negated character class
eeAiiZooAuuZZeeeZZfff      r = reluctant
  \_________/r   /         g = greedy
   \____________/g

Related topics

These are links to questions and answers on stackoverflow that cover some topics that may be of interest.

One greedy repetition can outgreed another

How to rotate a 3D object on axis three.js?

In Three.js R66, this is what I use (CoffeeScript version):

THREE.Object3D.prototype.rotateAroundWorldAxis = (axis, radians) ->
  rotWorldMatrix = new THREE.Matrix4()
  rotWorldMatrix.makeRotationAxis axis.normalize(), radians
  rotWorldMatrix.multiply this.matrix
  this.matrix = rotWorldMatrix
  this.rotation.setFromRotationMatrix this.matrix

How to select into a variable in PL/SQL when the result might be null?

From all the answers above, Björn's answer seems to be the most elegant and short. I personally used this approach many times. MAX or MIN function will do the job equally well. Complete PL/SQL follows, just the where clause should be specified.

declare v_column my_table.column%TYPE;
begin
    select MIN(column) into v_column from my_table where ...;
    DBMS_OUTPUT.PUT_LINE('v_column=' || v_column);
end;

Rotate label text in seaborn factorplot

If anyone wonders how to this for clustermap CorrGrids (part of a given seaborn example):

import seaborn as sns
import matplotlib.pyplot as plt
sns.set(context="paper", font="monospace")

# Load the datset of correlations between cortical brain networks
df = sns.load_dataset("brain_networks", header=[0, 1, 2], index_col=0)
corrmat = df.corr()

# Set up the matplotlib figure
f, ax = plt.subplots(figsize=(12, 9))

# Draw the heatmap using seaborn
g=sns.clustermap(corrmat, vmax=.8, square=True)
rotation = 90 
for i, ax in enumerate(g.fig.axes):   ## getting all axes of the fig object
     ax.set_xticklabels(ax.get_xticklabels(), rotation = rotation)


g.fig.show()

Is there a way to get a textarea to stretch to fit its content without using PHP or JavaScript?

one line only

<textarea name="text" oninput='this.style.height = "";this.style.height = this.scrollHeight + "px"'></textarea>

How to select an element inside "this" in jQuery?

$( this ).find( 'li.target' ).css("border", "3px double red");

or

$( this ).children( 'li.target' ).css("border", "3px double red");

Use children for immediate descendants, or find for deeper elements.

How to get character for a given ascii value

There are a few ways to do this.

Using char struct (to string and back again)

string _stringOfA = char.ConvertFromUtf32(65);

int _asciiOfA = char.ConvertToUtf32("A", 0);

Simply casting the value (char and string shown)

char _charA = (char)65;

string _stringA = ((char)65).ToString();

Using ASCIIEncoding.
This can be used in a loop to do a whole array of bytes

var _bytearray = new byte[] { 65 };

ASCIIEncoding _asiiencode = new ASCIIEncoding();

string _alpha = _asiiencode .GetString(_newByte, 0, 1);

You can override the type converter class, this would allow you to do some fancy validation of the values:

var _converter = new ASCIIConverter();

string _stringA = (string)_converter.ConvertFrom(65);

int _intOfA = (int)_converter.ConvertTo("A", typeof(int));

Here is the Class:

public class ASCIIConverter : TypeConverter
{
    // Overrides the CanConvertFrom method of TypeConverter.
    // The ITypeDescriptorContext interface provides the context for the
    // conversion. Typically, this interface is used at design time to 
    // provide information about the design-time container.
    public override bool CanConvertFrom(ITypeDescriptorContext context,
       Type sourceType)
    {
        if (sourceType == typeof(string))
        {
            return true;
        }
        return base.CanConvertFrom(context, sourceType);
    }

    public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
    {
        if (destinationType == typeof(int))
        {
            return true;
        }
        return base.CanConvertTo(context, destinationType);
    }


    // Overrides the ConvertFrom method of TypeConverter.
    public override object ConvertFrom(ITypeDescriptorContext context,
       CultureInfo culture, object value)
    {

        if (value is int)
        {
            //you can validate a range of int values here
            //for instance 
            //if (value >= 48 && value <= 57)
            //throw error
            //end if

            return char.ConvertFromUtf32(65);
        }
        return base.ConvertFrom(context, culture, value);
    }

    // Overrides the ConvertTo method of TypeConverter.
    public override object ConvertTo(ITypeDescriptorContext context,
       CultureInfo culture, object value, Type destinationType)
    {
        if (destinationType == typeof(int))
        {
            return char.ConvertToUtf32((string)value, 0);
        }
        return base.ConvertTo(context, culture, value, destinationType);
    }
}

`getchar()` gives the same output as the input string

Strings, by C definition, are terminated by '\0'. You have no "C strings" in your program.

Your program reads characters (buffered till ENTER) from the standard input (the keyboard) and writes them back to the standard output (the screen). It does this no matter how many characters you type or for how long you do this.

To stop the program you have to indicate that the standard input has no more data (huh?? how can a keyboard have no more data?).

You simply press Ctrl+D (Unix) or Ctrl+Z (Windows) to pretend the file has reached its end.
Ctrl+D (or Ctrl+Z) are not really characters in the C sense of the word.

If you run your program with input redirection, the EOF is the actual end of file, not a make belief one
./a.out < source.c

How to chain scope queries with OR instead of AND?

names = ["tim", "tom", "bob", "alex"]
sql_string = names.map { |t| "name = '#{t}'" }.join(" OR ")
@people = People.where(sql_string)

Center an item with position: relative

If you have a relatively- (or otherwise-) positioned div you can center something inside it with margin:auto

Vertical centering is a bit tricker, but possible.

How can I make a HTML a href hyperlink open a new window?

<a href="#" onClick="window.open('http://www.yahoo.com', '_blank')">test</a>

Easy as that.

Or without JS

<a href="http://yahoo.com" target="_blank">test</a>

Getting JSONObject from JSONArray

Make use of Android Volly library as much as possible. It maps your JSON reponse in respective class objects. You can add getter setter for that response model objects. And then you can access these JSON values/parameter using .operator like normal JAVA Object. It makes response handling very simple.

Clear data in MySQL table with PHP?

Actually I believe the MySQL optimizer carries out a TRUNCATE when you DELETE all rows.

Python: find position of element in array

Have you thought about using Python list's .index(value) method? It return the index in the list of where the first instance of the value passed in is found.

Sanitizing user input before adding it to the DOM in Javascript

Since the text that you are escaping will appear in an HTML attribute, you must be sure to escape not only HTML entities but also HTML attributes:

var ESC_MAP = {
    '&': '&amp;',
    '<': '&lt;',
    '>': '&gt;',
    '"': '&quot;',
    "'": '&#39;'
};

function escapeHTML(s, forAttribute) {
    return s.replace(forAttribute ? /[&<>'"]/g : /[&<>]/g, function(c) {
        return ESC_MAP[c];
    });
}

Then, your escaping code becomes var user_id = escapeHTML(id, true).

For more information, see Foolproof HTML escaping in Javascript.

PowerShell: Create Local User Account

Another alternative is the old school NET USER commands:

NET USER username "password" /ADD

OK - you can't set all the options but it's a lot less convoluted for simple user creation & easy to script up in Powershell.

NET LOCALGROUP "group" "user" /add to set group membership.

How to store an array into mysql?

You can always serialize the array and store that in the database.
PHP Serialize

You can then unserialize the array when needed.

Best way to store a key=>value array in JavaScript?

Simply do this

var key = "keyOne";
var obj = {};
obj[key] = someValue;

Way to create multiline comments in Bash?

Here's how I do multiline comments in bash.

This mechanism has two advantages that I appreciate. One is that comments can be nested. The other is that blocks can be enabled by simply commenting out the initiating line.

#!/bin/bash
# : <<'####.block.A'
echo "foo {" 1>&2
fn data1
echo "foo }" 1>&2
: <<'####.block.B'
fn data2 || exit
exit 1
####.block.B
echo "can't happen" 1>&2
####.block.A

In the example above the "B" block is commented out, but the parts of the "A" block that are not the "B" block are not commented out.

Running that example will produce this output:

foo {
./example: line 5: fn: command not found
foo }
can't happen

Django: List field in model?

If you're on Django 1.10 or newer AND Postgres as your database, you can use ArrayField. It's better to use than django-taggit or other alternatives, as it's native to the Django framework. https://docs.djangoproject.com/en/3.1/ref/contrib/postgres/fields/#arrayfield

from django.db import models
from django.contrib.postgres.fields import ArrayField

class ChessBoard(models.Model):
    board = ArrayField(
        ArrayField(
            models.CharField(max_length=10, blank=True),
            size=8,
        ),
        size=8,
    )

If you're on Django 3.1 or newer they've added support for JSONField with most database backends (MariaDB 10.2.7+, MySQL 5.7.8+, Oracle, PostgreSQL, and SQLite 3.9.0+). You can use this to store your Array!

https://docs.djangoproject.com/en/3.1/ref/models/fields/#jsonfield

from django.db import models

class ChessBoard(models.Model):
    list_of_pieces = models.JSONField()

Is there an opposite to display:none?

You can use display: block

Example :

<!DOCTYPE html>
<html>
<body>

<p id="demo">Lorem Ipsum</p>

<button type="button" 
onclick="document.getElementById('demo').style.display='none'">Click Me!</button>
<button type="button" 
onclick="document.getElementById('demo').style.display='block'">Click Me!</button>

</body>
</html> 

Convert SVG to PNG in Python

Actually, I did not want to be dependent of anything else but Python (Cairo, Ink.., etc.) My requirements were to be as simple as possible, at most, a simple pip install "savior" would suffice, that's why any of those above didn't suit for me.

I came through this (going further than Stackoverflow on the research). https://www.tutorialexample.com/best-practice-to-python-convert-svg-to-png-with-svglib-python-tutorial/

Looks good, so far. So I share it in case anyone in the same situation.

Git reset single file in feature branch to be the same as in master

If you want to revert the file to its state in master:

git checkout origin/master [filename]

Error :The remote server returned an error: (401) Unauthorized

The answers did help, but I think a full implementation of this will help a lot of people.

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Text;

namespace Dom
{
    class Dom
    {
        public static string make_Sting_From_Dom(string reportname)
        {
            try
            {
                WebClient client = new WebClient();
                client.Credentials = CredentialCache.DefaultCredentials;
                // Retrieve resource as a stream               
                Stream data = client.OpenRead(new Uri(reportname.Trim()));
                // Retrieve the text
                StreamReader reader = new StreamReader(data);
                string htmlContent = reader.ReadToEnd();
                string mtch = "TILDE";
                bool b = htmlContent.Contains(mtch);

                if (b)
                {
                    int index = htmlContent.IndexOf(mtch);
                    if (index >= 0)
                        Console.WriteLine("'{0} begins at character position {1}",
                        mtch, index + 1);
                }
                // Cleanup
                data.Close();
                reader.Close();
                return htmlContent;
            }
            catch (Exception)
            {
                throw;
            }
        }

        static void Main(string[] args)
        {
            make_Sting_From_Dom("https://www.w3.org/TR/PNG/iso_8859-1.txt");
        }
    }
}

pandas read_csv and filter columns with usecols

If your csv file contains extra data, columns can be deleted from the DataFrame after import.

import pandas as pd
from StringIO import StringIO

csv = r"""dummy,date,loc,x
bar,20090101,a,1
bar,20090102,a,3
bar,20090103,a,5
bar,20090101,b,1
bar,20090102,b,3
bar,20090103,b,5"""

df = pd.read_csv(StringIO(csv),
        index_col=["date", "loc"], 
        usecols=["dummy", "date", "loc", "x"],
        parse_dates=["date"],
        header=0,
        names=["dummy", "date", "loc", "x"])
del df['dummy']

Which gives us:

                x
date       loc
2009-01-01 a    1
2009-01-02 a    3
2009-01-03 a    5
2009-01-01 b    1
2009-01-02 b    3
2009-01-03 b    5

Permission denied (publickey) when deploying heroku code. fatal: The remote end hung up unexpectedly

On Windows 7,64 bit,the above solution (Onur Turhan's) worked for me with slight changes as below

C:\Users\MyName > heroku login

Enter email/password

C:\Users\MyName >ssh-keygen -t rsa -f id_rsa

This generated two files(id_rsa and id_rsa.pub) in my c:\Users\MyName directory (Not in .ssh directory)

heroku keys:add id_rsa.pub
git clone [email protected]:some-heiku-xxxx.git -o heroku

I guess adding the correct "id_rsa.pub" file is the most important.After generating the public key using keygen just verify that you are adding correct key by looking at the time-stamp when it was created.

Is it possible to opt-out of dark mode on iOS 13?

Here are a few tips and tricks which you can use in your app to support or bypass the dark mode.

First tip: To override the ViewController style

you can override the interface style of UIViewController by

1: overrideUserInterfaceStyle = .dark //For dark mode

2: overrideUserInterfaceStyle = .light //For light mode

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        overrideUserInterfaceStyle = .light    
    }
}

Second tip: Adding a key in info.plist

Simply you can add a new key

UIUserInterfaceStyle

in your app info.plist and set its value to Light or Dark. this will override the app default style to the value you provide. You don't have to add overrideUserInterfaceStyle = .light this line in every viewController, just one line in info.plist that’s it.

Calculate difference in keys contained in two Python dictionaries

There is an other question in stackoverflow about this argument and i have to admit that there is a simple solution explained: the datadiff library of python helps printing the difference between two dictionaries.

How to redirect to logon page when session State time out is completed in asp.net mvc

There is a generic solution:

Lets say you have a controller named Admin where you put content for authorized users.

Then, you can override the Initialize or OnAuthorization methods of Admin controller and write redirect to login page logic on session timeout in these methods as described:

protected override void OnAuthorization(System.Web.Mvc.AuthorizationContext filterContext)
    {
        //lets say you set session value to a positive integer
        AdminLoginType = Convert.ToInt32(filterContext.HttpContext.Session["AdminLoginType"]);
        if (AdminLoginType == 0)
        {
            filterContext.HttpContext.Response.Redirect("~/login");
        }

        base.OnAuthorization(filterContext);
    }

How do I put all required JAR files in a library folder inside the final JAR file with Maven?

following this link:

How To: Eclipse Maven install build jar with dependencies

i found out that this is not workable solution because the class loader doesn't load jars from within jars, so i think that i will unpack the dependencies inside the jar.

Import .bak file to a database in SQL server

  1. Connect to a server you want to store your DB
  2. Right-click Database
  3. Click Restore
  4. Choose the Device radio button under the source section
  5. Click Add.
  6. Navigate to the path where your .bak file is stored, select it and click OK
  7. Enter the destination of your DB
  8. Enter the name by which you want to store your DB
  9. Click OK

Done

Give column name when read csv file pandas

user1  = pd.read_csv('dataset/1.csv',  names=['Time',  'X',  'Y',  'Z']) 

names parameter in read_csv function is used to define column names. If you pass extra name in this list, it will add another new column with that name with NaN values.

header=None is used to trim column names is already exists in CSV file.

Google Maps v2 - set both my location and zoom in

gmap.animateCamera(CameraUpdateFactory.newCameraPosition(new CameraPosition(new LatLng(9.491327, 76.571404), 10, 30, 0)));

Read/write to file using jQuery

Use javascript's execCommand('SaveAs', false, filename); functionality

Edit: No longer works. This Javascript function used to work across all browsers, but now only on IE, due to browser security considerations. It presented a "Save As" Dialog to the user who runs this function through their browser, the user presses OK and the file is saved by javascript on the server side.

Now this code is an rare antique zero day collectible.

// content is the data (a string) you'll write to file.
// filename is a string filename to write to on server side.
// This function uses iFrame as a buffer, it fills it up with your content
// and prompts the user to save it out.
function save_content_to_file(content, filename){
    var dlg = false;
    with(document){
     ir=createElement('iframe');
     ir.id='ifr';
     ir.location='about.blank';
     ir.style.display='none';
     body.appendChild(ir);
      with(getElementById('ifr').contentWindow.document){
           open("text/plain", "replace");
           charset = "utf-8";
           write(content);
           close();
           document.charset = "utf-8";
           dlg = execCommand('SaveAs', false, filename);
       }
       body.removeChild(ir);
     }
    return dlg;
}

Invoke the function like this:

msg =  "I am the president of tautology club.";
save_content_to_file(msg, "C:\\test");

How to check if DST (Daylight Saving Time) is in effect, and if so, the offset?

The getTimezoneOffset() method in JavaScript, in a browser, returns the number of minutes offset from the 00:00 time zone. For example, America/New_York time zone in Daylight Savings (DST) returns the number 300. 300 minutes is 5 hours difference from zero. 300 minutes divided by 60 minutes is 5 hours. Every time zone is compared to the zero time zone, +00:00 / Etc/GMT / Greenwich time.

MDN Web Docs

The next thing that you must know, is that the offset has the opposite sign of the actual time zone.

Information about time zones is maintained by the Internet Assigned Numbers Authority (iana)

iana time zones

A nicely formatted table of Time Zones is supplied by joda.org

joda-time Time Zones

+00:00 or Etc/GMT is Greenwich time

All time zones are offset from +00:00 / "Etc/GMT" / Greenwich time

Daylight Savings Time is always an earlier time than the "regular" time in the summer. You set your clocks back in the fall season. ("Fall Back" slogan to remember what to do)

So, America/New_York time in Daylight Savings (winter) is one hour before the regular time. So, for example, what was normally 5 p.m. in the afternoon in New York city in the summer, is now 4 p.m. America/New_York time in Daylight Savings. The name "America/New_York" time is a "Long Format" time zone name. The east coast of the U.S typically calls their time zone Eastern Standard Time (EST)

If you want to compare today's time zone offset to the time zone offset of some other date, you need to know that mathematical sign (+/- "Positive / Negative") of the time zone offset is the opposite of the time zone.

Look at the time zone table at joda.org and find the time zone for "America/New_York" It will have a negative sign in front of the Standard Offset.

The earth rotates counter-clockwise on it's axis. A person watch the sunrise in Greenwich sees the sunrise 5 hours before someone in New York City will see the sunrise. And someone on the West Coast of the U.S. will see the sunrise after someone on the East Coast of the U.S. sees the sunrise.

There's a reason why you need to know all of this. So that you'll be able to logically determine whether some JavaScript code is getting the DST status correctly or not, without needing to test every time zone at different times of the year.

Imagine that it's November in New York City, and the clocks have been set back an hour. In the summer in New York City, the offset is 240 minutes or 4 hours.

You can test this by creating a date that is in July and then getting the offset.

var July_Date = new Date(2017, 6, 1);
var july_Timezone_OffSet = July_Date.getTimezoneOffset();

console.log('july_Timezone_OffSet: ' + july_Timezone_OffSet)

What will print to the browser's developer tools console log?

Answer is: 240

So, now you can create a date in January and see what your browser returns for a time zone offset for the winter season.

var Jan_Date = new Date(2017, 0, 1);//Month is zero indexed - Jan is zero
var jan_Timezone_OffSet = Jan_Date.getTimezoneOffset();

console.log('jan_Timezone_OffSet: ' + jan_Timezone_OffSet)

Answer is: 300

Obviously 300 is bigger than 240. So, what does this mean? Should you write code that tests for the winter offset being bigger than the summer offset? Or the summer offset less than the winter offset? If there is a difference between the summer and winter time zone offsets, then you can assume that DST is being used for this time zone. But that doesn't tell you if today is using DST for the browsers time zone. So, you'll need to get the time zone offset for today.

var today = new Date();
var todaysTimeZone = today.getTimezoneOffset();

console.log('todaysTimeZone : ' + todaysTimeZone)

Answer is: ? - Depends on the time of year

If today's time zone offset and the summer time zone offset is the same, AND the summer and winter time zone offsets are different, then by logical deduction, today must be NOT be in DST.

Can you omit comparing the summer and winter time zone offsets, (To know if DST is used for this time zone) and just compare today's time zone offset to the summer TZ offset, and always get the correct answer?

today's TZ Offset !== Summer TZ Offset

Well, is today in the winter or summer? If you knew that then you could apply the following logic:

if ( it_is_winter && ( todays_TZ_Offset !== summer_TZ_Offset) {
  var are_We_In_DST = true;
}

But the problem is, that you don't know if today's date is in winter or summer. Every time zone can have it's own rules for when DST starts and stops. You'd need to keep track of every time zone's rules for every time zone in the world. So, if there is a better and easier way then you might as well do it the better and easier way.

What we are left with, is that you need to know if this time zone uses DST, and then compare today's time zone offset with the summer time zone offset. That will always give you a reliable answer.

The final logic is:

if ( DST_Is_Used_In_This_Time_Zone && ( todays_TZ_Offset !== summer_TZ_Offset) {
  var are_We_In_DST = true;
}

Function to determine if the time zone in the browser uses DST:

function is_DST_Used_In_This_TimeZone() {
  var Jan_Date, jan_Timezone_OffSet, July_Date, july_Timezone_OffSet 
      offsetsNotEqual, thisYear, today;

  today = new Date();//Create a date object that is now
  thisYear = today.getFullYear();//Get the year as a number

  Jan_Date = new Date(thisYear, 0, 1);//Month is zero indexed - Jan is zero
  jan_Timezone_OffSet = Jan_Date.getTimezoneOffset();

  console.log('jan_Timezone_OffSet: ' + jan_Timezone_OffSet)

  July_Date = new Date(thisYear, 6, 1);
  july_Timezone_OffSet = July_Date.getTimezoneOffset();

  console.log('july_Timezone_OffSet: ' + july_Timezone_OffSet)

  offsetsNotEqual = july_Timezone_OffSet !== jan_Timezone_OffSet;//True if not equal

  console.log('offsetsNotEqual: ' + offsetsNotEqual);

  return offsetsNotEqual;//If the offsets are not equal for summer and
       //winter then the only possible reason is that DST is used for
       //this time zone
}

Display a decimal in scientific notation

Here is the simplest one I could find.

format(40800000000.00000000000000, '.2E')
#'4.08E+10'

('E' is not case sensitive. You can also use '.2e')

Merge (with squash) all changes from another branch as a single commit

2020 updated

With the --squash flag it looks like two parallel branches with no relation:

enter image description here

Sorting commits related to date looks like:

enter image description here

Personally, i don't like --squash option, try this trick, maybe it fits your needs, i use it for small projects:

  1. git init
  2. git checkout -b dev
  3. Several commits in dev
  4. After you did some great commits in dev(but not merged to master yet), if you do not want all commits copied to master branch, then make intentionally change something in master and (add some empty lines in README file and commit in master),
  5. git merge dev It results merge conflict(empty lines in README), resolve it, commit with new message you want, and you are DONE. Here is the visual representation of it.

null commit for intentionally merge conflict, name it anything you prefer

null commit for intentionally merge conflict

How do I update a Tomcat webapp without restarting the entire service?

Have you tried to use Tomcat's Manager application? It allows you to undeploy / deploy war files with out shutting Tomcat down.

If you don't want to use the Manager application, you can also delete the war file from the webapps directory, Tomcat will undeploy the application after a short period of time. You can then copy a war file back into the directory, and Tomcat will deploy the war file.

If you are running Tomcat on Windows, you may need to configure your Context to not lock various files.

If you absolutely can't have any downtime, you may want to look at Tomcat 7's Parallel deployments You may deploy multiple versions of a web application with the same context path at the same time. The rules used to match requests to a context version are as follows:

  • If no session information is present in the request, use the latest version.
  • If session information is present in the request, check the session manager of each version for a matching session and if one is found, use that version.
  • If session information is present in the request but no matching session can be found, use the latest version.

What's the difference between commit() and apply() in SharedPreferences

The docs give a pretty good explanation of the difference between apply() and commit():

Unlike commit(), which writes its preferences out to persistent storage synchronously, apply() commits its changes to the in-memory SharedPreferences immediately but starts an asynchronous commit to disk and you won't be notified of any failures. If another editor on this SharedPreferences does a regular commit() while a apply() is still outstanding, the commit() will block until all async commits are completed as well as the commit itself. As SharedPreferences instances are singletons within a process, it's safe to replace any instance of commit() with apply() if you were already ignoring the return value.

Resolve Git merge conflicts in favor of their changes during a pull

I had a long-running next-version branch with tons of deletions to files that had changed on develop, files that had been added in different places on both branches, etc.

I wanted to take the entire contents of the next-version branch into develop, all in one whopping merge commit.

The combination of the above commands that worked for me was:

git merge -X theirs next-version
# lots of files left that were modified on develop but deleted on next-version
git checkout next-version .
# files removed, now add the deletions to the commit
git add .
# still have files that were added on develop; in my case they are all in web/
git rm -r web

Not a new answer, just combining bits from many answers, partly to reassure that you might need all of these answers.

Convert a string to a double - is this possible?

For arbitrary precision mathematics PHP offers the Binary Calculator which supports numbers of any size and precision, represented as strings.

$s = '1234.13';
$double = bcadd($s,'0',2);

PHP: bcadd

sql query to return differences between two tables

Try this :

SELECT 
    [First Name], [Last Name]
FROM 
    [Temp Test Data] AS td EXCEPTION JOIN [Data] AS d ON 
         (d.[First Name] = td.[First Name] OR d.[Last Name] = td.[Last Name])

Much simpler to read.

Django: ImproperlyConfigured: The SECRET_KEY setting must not be empty

Import base.py in __init__.py alone. make sure you won't repeat the same configuration again!.

set environment variable SET DJANGO_DEVELOPMENT =dev

settings/
  __init__.py
  base.py
  local.py
  production.py

In __init__.py

from .base import *
if os.environ.get('DJANGO_DEVELOPMENT')=='prod':
   from .production import *
else:
   from .local import *

In base.py configured the global configurations. except for Database. like

SECRET_KEY, ALLOWED_HOSTS,INSTALLED_APPS,MIDDLEWARE .. etc....

In local.py

DATABASES = {
'default': {
    'ENGINE': 'django.db.backends.postgresql_psycopg2',
    'NAME': 'database',
    'USER': 'postgres',
    'PASSWORD': 'password',
    'HOST': 'localhost',
    'PORT': '5432',
}
}

Basic HTML - how to set relative path to current folder?

For anyone who has found this thread, addressing relative paths has always created arguments over what is correct or not.

Depending on where you use the path to be addressed, it will depend on how you address the path.

Generally :

. and ./ do the same thing, however you wouldn't use . with a file name. Otherwise you will have the browser requesting .filename.ext as a file from the server. The proper method would be ./filename.ext.

../ addresses the path up one level from the current folder. If you were in the path /cheese/crackers/yummy.html, and your link code asked for ../butter/spread.html in the document yummy.html, then you would be addressing the path /cheese/butter/spread.html, as far as the server was concerned.

/ will always address the root of the site.

How to process images of a video, frame by frame, in video streaming using OpenCV and Python

This is how I would start to solve this:

  1. Create a video writer:

    import cv2.cv as cv
    videowriter = cv.CreateVideoWriter( filename, fourcc, fps, frameSize)
    

    Check here for valid parameters

  2. Loop to retrieve[1] and write the frames:

    cv.WriteFrame( videowriter, frame )
    

    WriteFrame doc

[1] zenpoy already pointed in the correct direction. You just need to know that you can retrieve images from a webcam or a file :-)

Hopefully I understood the requirements correct.

How do I compare two Integers?

Minor note: since Java 1.7 the Integer class has a static compare(Integer, Integer) method, so you can just call Integer.compare(x, y) and be done with it (questions about optimization aside).

Of course that code is incompatible with versions of Java before 1.7, so I would recommend using x.compareTo(y) instead, which is compatible back to 1.2.

Finding sum of elements in Swift array

For me, it was like this using property

    let blueKills = match.blueTeam.participants.reduce(0, { (result, participant) -> Int in
        result + participant.kills
    })

keycode and charcode

Handling key events consistently is not at all easy.

Firstly, there are two different types of codes: keyboard codes (a number representing the key on the keyboard the user pressed) and character codes (a number representing a Unicode character). You can only reliably get character codes in the keypress event. Do not try to get character codes for keyup and keydown events.

Secondly, you get different sets of values in a keypress event to what you get in a keyup or keydown event.

I recommend this page as a useful resource. As a summary:

If you're interested in detecting a user typing a character, use the keypress event. IE bizarrely only stores the character code in keyCode while all other browsers store it in which. Some (but not all) browsers also store it in charCode and/or keyCode. An example keypress handler:

function(evt) {
  evt = evt || window.event;
  var charCode = evt.which || evt.keyCode;
  var charStr = String.fromCharCode(charCode);
  alert(charStr);
}

If you're interested in detecting a non-printable key (such as a cursor key), use the keydown event. Here keyCode is always the property to use. Note that keyup events have the same properties.

function(evt) {
  evt = evt || window.event;
  var keyCode = evt.keyCode;

  // Check for left arrow key
  if (keyCode == 37) {
    alert("Left arrow");
  }
}

Where can I get a virtual machine online?

Try this:

http://aws.amazon.com/free/

one year free. I do use this for a while.

how to rename an index in a cluster?

Another different way to achieve the renaming or change the mappings for an index is to reindex using logstash. Here is a sample of the logstash 2.1 configuration:

input {
  elasticsearch {
   hosts => ["es01.example.com", "es02.example.com"]
   index => "old-index-name"
   size => 500
   scroll => "5m"
  }
}
filter {

 mutate {
  remove_field => [ "@version" ]
 }

 date {
   "match" => [ "custom_timestamp", "MM/dd/YYYY HH:mm:ss" ]
   target => "@timestamp"
 }

}
output {
 elasticsearch {
   hosts => ["es01.example.com", "es02.example.com" ]
   manage_template => false
   index => "new-index-name"
 }
}

What does "select 1 from" do?

It does what you ask, SELECT 1 FROM table will SELECT (return) a 1 for every row in that table, if there were 3 rows in the table you would get

1
1
1

Take a look at Count(*) vs Count(1) which may be the issue you were described.

How to select the rows with maximum values in each group with dplyr?

You can use top_n

df %>% group_by(A, B) %>% top_n(n=1)

This will rank by the last column (value) and return the top n=1 rows.

Currently, you can't change the this default without causing an error (See https://github.com/hadley/dplyr/issues/426)

TypeError: 'list' object cannot be interpreted as an integer

In playSound(), instead of

for i in range(myList):

try

for i in myList:

This will iterate over the contents of myList, which I believe is what you want. range(myList) doesn't make any sense.

Search text in stored procedure in SQL Server

You can also use

CREATE PROCEDURE [Search](
    @Filter nvarchar(max)
)
AS
BEGIN

SELECT name
FROM   procedures
WHERE   definition LIKE '%'+@Filter+'%'

END

and then run

exec [Search] 'text'

Getting a UnhandledPromiseRejectionWarning when testing using mocha/chai

The issue is caused by this:

.catch((error) => {
  assert.isNotOk(error,'Promise error');
  done();
});

If the assertion fails, it will throw an error. This error will cause done() never to get called, because the code errored out before it. That's what causes the timeout.

The "Unhandled promise rejection" is also caused by the failed assertion, because if an error is thrown in a catch() handler, and there isn't a subsequent catch() handler, the error will get swallowed (as explained in this article). The UnhandledPromiseRejectionWarning warning is alerting you to this fact.

In general, if you want to test promise-based code in Mocha, you should rely on the fact that Mocha itself can handle promises already. You shouldn't use done(), but instead, return a promise from your test. Mocha will then catch any errors itself.

Like this:

it('should transition with the correct event', () => {
  ...
  return new Promise((resolve, reject) => {
    ...
  }).then((state) => {
    assert(state.action === 'DONE', 'should change state');
  })
  .catch((error) => {
    assert.isNotOk(error,'Promise error');
  });
});

Server configuration is missing in Eclipse

I faced the same problem once. THe reason for this is that even though the server is available, the config files are missing. You can see the server at Windows -> Show view -> Servers. Their configuration files can be seen at Project Explorer -> Servers. For some reason this second mentioned config files were missing.

I simply deleted the existing server and created a new one with this the config files were also created and the problem was solved!

Similar solution is given at here by Emertana EM java.lang.NoClassDefFoundError: org/apache/juli/logging/LogFactory

UIButton action in table view cell

As Apple DOC

targetForAction:withSender:
Returns the target object that responds to an action.

You can't use that method to set target for UIButton.
Try addTarget(_:action:forControlEvents:) method

Angular 4 img src is not found

Well, the problem was that, somehow, the path was not recognized when was inserted in src by a variable. I had to create a variable like this:

path:any = require("../../img/myImage.png");

and then I can use it in src. Thanks everyone!

byte array to pdf

You shouldn't be using the BinaryFormatter for this - that's for serializing .Net types to a binary file so they can be read back again as .Net types.

If it's stored in the database, hopefully, as a varbinary - then all you need to do is get the byte array from that (that will depend on your data access technology - EF and Linq to Sql, for example, will create a mapping that makes it trivial to get a byte array) and then write it to the file as you do in your last line of code.

With any luck - I'm hoping that fileContent here is the byte array? In which case you can just do

System.IO.File.WriteAllBytes("hello.pdf", fileContent);

How do I disable text selection with CSS or JavaScript?

You can use JavaScript to do what you want:


if (document.addEventListener !== undefined) {
  // Not IE
  document.addEventListener('click', checkSelection, false);
} else {
  // IE
  document.attachEvent('onclick', checkSelection);
}

function checkSelection() {
    var sel = {};
    if (window.getSelection) {
        // Mozilla
        sel = window.getSelection();
    } else if (document.selection) {
        // IE
        sel = document.selection.createRange();
    }

    // Mozilla
    if (sel.rangeCount) {
        sel.removeAllRanges();
        return;
    }

    // IE
    if (sel.text > '') {
        document.selection.empty();
        return;
    }
}

Soap box: You really shouldn't be screwing with the client's user agent in this manner. If the client wants to select things on the document, then they should be able to select things on the document. It doesn't matter if you don't like the highlight color, because you aren't the one viewing the document.

Create table variable in MySQL

If you don't want to store table in database then @Evan Todd already has been provided temporary table solution.

But if you need that table for other users and want to store in db then you can use below procedure.

Create below ‘stored procedure’:

————————————

DELIMITER $$

USE `test`$$

DROP PROCEDURE IF EXISTS `sp_variable_table`$$

CREATE DEFINER=`root`@`localhost` PROCEDURE `sp_variable_table`()
BEGIN

SELECT CONCAT(‘zafar_’,REPLACE(TIME(NOW()),’:',’_')) INTO @tbl;

SET @str=CONCAT(“create table “,@tbl,” (pbirfnum BIGINT(20) NOT NULL DEFAULT ’0', paymentModes TEXT ,paymentmodeDetails TEXT ,shippingCharges TEXT ,shippingDetails TEXT ,hypenedSkuCodes TEXT ,skuCodes TEXT ,itemDetails TEXT ,colorDesc TEXT ,size TEXT ,atmDesc TEXT ,promotional TEXT ,productSeqNumber VARCHAR(16) DEFAULT NULL,entity TEXT ,entityDetails TEXT ,kmtnmt TEXT ,rating BIGINT(1) DEFAULT NULL,discount DECIMAL(15,0) DEFAULT NULL,itemStockDetails VARCHAR(38) NOT NULL DEFAULT ”) ENGINE=INNODB DEFAULT CHARSET=utf8");
PREPARE stmt FROM @str;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

SELECT ‘Table has been created’;
END$$

DELIMITER ;

———————————————–

Now you can execute this procedure to create a variable name table as per below-

call sp_variable_table();

You can check new table after executing below command-

use test;show tables like ‘%zafar%’; — test is here ‘database’ name.

You can also check more details at below path-

http://mydbsolutions.in/how-can-create-a-table-with-variable-name/

How do getters and setters work?

1. The best getters / setters are smart.

Here's a javascript example from mozilla:

var o = { a:0 } // `o` is now a basic object

Object.defineProperty(o, "b", { 
    get: function () { 
        return this.a + 1; 
    } 
});

console.log(o.b) // Runs the getter, which yields a + 1 (which is 1)

I've used these A LOT because they are awesome. I would use it when getting fancy with my coding + animation. For example, make a setter that deals with an Number which displays that number on your webpage. When the setter is used it animates the old number to the new number using a tweener. If the initial number is 0 and you set it to 10 then you would see the numbers flip quickly from 0 to 10 over, let's say, half a second. Users love this stuff and it's fun to create.

2. Getters / setters in php

Example from sof

<?php
class MyClass {
  private $firstField;
  private $secondField;

  public function __get($property) {
    if (property_exists($this, $property)) {
      return $this->$property;
    }
  }

  public function __set($property, $value) {
    if (property_exists($this, $property)) {
      $this->$property = $value;
    }

    return $this;
  }
}
?>

citings:

Connect multiple devices to one device via Bluetooth

That is partly possible (for max 2 devices), because device can be connected only to one other device same time. Better solution in your case will be create an TCP server which sends informations to other devices - but that, of course, requires internet connection. Read also about Samsung Chord API - it provides functions which you need, but then every devices have to be connected to one and the same Wi-Fi network

Negation in Python

The negation operator in Python is not. Therefore just replace your ! with not.

For your example, do this:

if not os.path.exists("/usr/share/sounds/blues") :
    proc = subprocess.Popen(["mkdir", "/usr/share/sounds/blues"])
    proc.wait()

For your specific example (as Neil said in the comments), you don't have to use the subprocess module, you can simply use os.mkdir() to get the result you need, with added exception handling goodness.

Example:

blues_sounds_path = "/usr/share/sounds/blues"
if not os.path.exists(blues_sounds_path):
    try:
        os.mkdir(blues_sounds_path)
    except OSError:
        # Handle the case where the directory could not be created.

How to create strings containing double quotes in Excel formulas?

Three double quotes: " " " x " " " = "x" Excel will auto change to one double quote. e.g.:

=CONCATENATE("""x"""," hi")  

= "x" hi

IF/ELSE Stored Procedure

try

IF(@Trans_type = 'subscr_signup')    
BEGIN 
 set @tmpType = 'premium' 
 END
ELSE iF(@Trans_type = 'subscr_cancel')  
  begin
     set    @tmpType = 'basic'  
  END

I can't find my git.exe file in my Github folder

1) Install Git for Windows from here: http://git-scm.com/download/win

2) Note: During installation, Make sure "Use Git and optional Unix tools from the windows command prompt" is selected enter image description here

3) restart the Android Studio and try again

4) Go to File-> New -> Project from version control -> Git

Declaring a boolean in JavaScript using just var

No it is not safe. You could later do var IsLoggedIn = "Foo"; and JavaScript will not throw an error.

It is possible to do

var IsLoggedIn = new Boolean(false);
var IsLoggedIn = new Boolean(true);

You can also pass the non boolean variable into the new Boolean() and it will make IsLoggedIn boolean.

var IsLoggedIn = new Boolean(0); // false
var IsLoggedIn = new Boolean(NaN); // false
var IsLoggedIn = new Boolean("Foo"); // true
var IsLoggedIn = new Boolean(1); // true

How do I get Month and Date of JavaScript in 2 digit format?

function GetDateAndTime(dt) {
  var arr = new Array(dt.getDate(), dt.getMonth(), dt.getFullYear(),dt.getHours(),dt.getMinutes(),dt.getSeconds());

  for(var i=0;i<arr.length;i++) {
    if(arr[i].toString().length == 1) arr[i] = "0" + arr[i];
  }

  return arr[0] + "." + arr[1] + "." + arr[2] + " " + arr[3] + ":" + arr[4] + ":" + arr[5]; 
}

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

This code extracts the YouTube video duration using the YouTube API v3 by passing a video ID. It worked for me.

<?php
    function getDuration($videoID){
       $apikey = "YOUR-Youtube-API-KEY"; // Like this AIcvSyBsLA8znZn-i-aPLWFrsPOlWMkEyVaXAcv
       $dur = file_get_contents("https://www.googleapis.com/youtube/v3/videos?part=contentDetails&id=$videoID&key=$apikey");
       $VidDuration =json_decode($dur, true);
       foreach ($VidDuration['items'] as $vidTime)
       {
           $VidDuration= $vidTime['contentDetails']['duration'];
       }
       preg_match_all('/(\d+)/',$VidDuration,$parts);
       return $parts[0][0] . ":" .
              $parts[0][1] . ":".
              $parts[0][2]; // Return 1:11:46 (i.e.) HH:MM:SS
    }

    echo getDuration("zyeubYQxHyY"); // Video ID
?>

You can get your domain's own YouTube API key on https://console.developers.google.com and generate credentials for your own requirement.

How to trim white space from all elements in array?

In Java 8, Arrays.parallelSetAll seems ready made for this purpose:

import java.util.Arrays;

Arrays.parallelSetAll(array, (i) -> array[i].trim());

This will modify the original array in place, replacing each element with the result of the lambda expression.

Standard Android Button with a different color

You can Also use this online tool to customize your button http://angrytools.com/android/button/ and use android:background="@drawable/custom_btn" to define the customized button in your layout.

How do I escape a percentage sign in T-SQL?

You can use the code below to find a specific value.

WHERE col1 LIKE '%[%]75%'

When you want a single digit number after the% sign, you can write the following code.

WHERE col2 LIKE '%[%]_'