Programs & Examples On #Server response

How to get database structure in MySQL via query

Nowadays, people use DESC instead of DESCRIPTION. For example:- DESC users;

Adding machineKey to web.config on web-farm sites

If you are using IIS 7.5 or later you can generate the machine key from IIS and save it directly to your web.config, within the web farm you then just copy the new web.config to each server.

  1. Open IIS manager.
  2. If you need to generate and save the MachineKey for all your applications select the server name in the left pane, in that case you will be modifying the root web.config file (which is placed in the .NET framework folder). If your intention is to create MachineKey for a specific web site/application then select the web site / application from the left pane. In that case you will be modifying the web.config file of your application.
  3. Double-click the Machine Key icon in ASP.NET settings in the middle pane:
  4. MachineKey section will be read from your configuration file and be shown in the UI. If you did not configure a specific MachineKey and it is generated automatically you will see the following options:
  5. Now you can click Generate Keys on the right pane to generate random MachineKeys. When you click Apply, all settings will be saved in the web.config file.

Full Details can be seen @ Easiest way to generate MachineKey – Tips and tricks: ASP.NET, IIS and .NET development…

Circular gradient in android

Here is the complete xml with gradient, stoke & circular shape.

<?xml version="1.0" encoding="utf-8"?>

<shape
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval" >

    <!-- You can use gradient with below attributes-->
    <gradient
        android:angle="90"
        android:centerColor="#555994"
        android:endColor="#b5b6d2"
        android:startColor="#555994"
        android:type="linear" />

    <!-- You can omit below tag if you don't need stroke -->
   <stroke android:color="#3b91d7" android:width="5dp"/>

    <!-- Set the same value for both width and height to get a circular shape -->
    <size android:width="200dp" android:height="200dp"/>


    <!--if you need only a single color filled shape-->
    <solid android:color="#e42828"/>


</shape>

Rearrange columns using cut

Just as an addition to answers that suggest to duplicate the columns and then to do cut. For duplication, paste etc. will work only for files, but not for streams. In that case, use sed instead.

cat file.txt | sed s/'.*'/'&\t&'/ | cut -f2,3

This works on both files and streams, and this is interesting if instead of just reading from a file with cat, you do something interesting before re-arranging the columns.

By comparison, the following does not work:

cat file.txt | paste - - | cut -f2,3

Here, the double stdin placeholder paste does not duplicate stdin, but reads the next line.

Is there a short contains function for lists?

You can use this syntax:

if myItem in list:
    # do something

Also, inverse operator:

if myItem not in list:
    # do something

It's work fine for lists, tuples, sets and dicts (check keys).

Note that this is an O(n) operation in lists and tuples, but an O(1) operation in sets and dicts.

java.math.BigInteger cannot be cast to java.lang.Integer

You can use:

Integer grandChildCount = ((BigInteger) result[1]).intValue();

Or perhaps cast to Number to cover both Integer and BigInteger values.

jQuery.inArray(), how to use it right?

If we want to check an element is inside a set of elements we can do for example:

var checkboxes_checked = $('input[type="checkbox"]:checked');

// Whenever a checkbox or input text is changed
$('input[type="checkbox"], input[type="text"]').change(function() {
    // Checking if the element was an already checked checkbox
    if($.inArray( $(this)[0], checkboxes_checked) !== -1) {
        alert('this checkbox was already checked');
    }
}

Appending a line break to an output file in a shell script

You can do that without an I/O redirection:

sed -i 's/$/\n/' filename

You can also use this command to append a newline to a list of files:

find dir -name filepattern | xargs sed -i 's/$/\n/' filename

For echo, some shells implement it as a shell builtin command. It might not accept the -e option. If you still want to use echo, try to find where the echo binary file is, using which echo. In most cases, it is located in /bin/echo, so you can use /bin/echo -e "\n" to echo a new line.

How to set the color of an icon in Angular Material?

Or simply

add to your element

[ngStyle]="{'color': myVariableColor}"

eg

<mat-icon [ngStyle]="{'color': myVariableColor}">{{ getActivityIcon() }}</mat-icon>

Where color can be defined at another component etc

How to redirect output of an entire shell script within the script itself?

Addressing the question as updated.

#...part of script without redirection...

{
    #...part of script with redirection...
} > file1 2>file2 # ...and others as appropriate...

#...residue of script without redirection...

The braces '{ ... }' provide a unit of I/O redirection. The braces must appear where a command could appear - simplistically, at the start of a line or after a semi-colon. (Yes, that can be made more precise; if you want to quibble, let me know.)

You are right that you can preserve the original stdout and stderr with the redirections you showed, but it is usually simpler for the people who have to maintain the script later to understand what's going on if you scope the redirected code as shown above.

The relevant sections of the Bash manual are Grouping Commands and I/O Redirection. The relevant sections of the POSIX shell specification are Compound Commands and I/O Redirection. Bash has some extra notations, but is otherwise similar to the POSIX shell specification.

Check cell for a specific letter or set of letters

Some options without REGEXMATCH, since you might want to be case insensitive and not want say blast or ablative to trigger a YES. Using comma as the delimiter, as in the OP, and for the moment ignoring the IF condition:

First very similar to @user1598086's answer:

=FIND("bla",A1)

Is case sensitive but returns #VALUE! rather than NO and a number rather than YES (both of which can however be changed to NO/YES respectively).

=SEARCH("bla",A1)  

Case insensitive, so treats Black and black equally. Returns as above.

The former (for the latter equivalent) to indicate whether bla present after the first three characters in A1:

=FIND("bla",A1,4)  

Returns a number for blazer, black but #VALUE! for blazer, blue.

To find Bla only when a complete word on its own (ie between spaces - not at the start or end of a 'sentence'):

=SEARCH(" Bla ",A1) 

Since the return in all cases above is either a number ("found", so YES preferred) or #VALUE! we can use ISERROR to test for #VALUE! within an IF formula, for instance taking the first example above:

 =if(iserror(FIND("bla",A1)),"NO","YES")  

Longer than the regexmatch but the components are easily adjustable.

$lookup on ObjectId's in an array

Aggregating with $lookup and subsequent $group is pretty cumbersome, so if (and that's a medium if) you're using node & Mongoose or a supporting library with some hints in the schema, you could use a .populate() to fetch those documents:

var mongoose = require("mongoose"),
    Schema = mongoose.Schema;

var productSchema = Schema({ ... });

var orderSchema = Schema({
  _id     : Number,
  products: [ { type: Schema.Types.ObjectId, ref: "Product" } ]
});

var Product = mongoose.model("Product", productSchema);
var Order   = mongoose.model("Order", orderSchema);

...

Order
    .find(...)
    .populate("products")
    ...

how to get the base url in javascript

One way is to use a script tag to import the variables you want to your views:

<script type="text/javascript">
window.base_url = <?php echo json_encode(base_url()); ?>;
</script>

Here, I wrapped the base_url with json_encode so that it'll automatically escape any characters to valid Javascript. I put base_url to the global Window so you can use it anywhere just by calling base_url, but make sure to put the script tag above any Javascript that calls it. With your given example:

...
$('#style_color').attr("href", base_url + "assets/css/themes/" + color_ + ".css");

What is the difference between print and puts?

A big difference is if you are displaying arrays. Especially ones with NIL. For example:

print [nil, 1, 2]

gives

[nil, 1, 2]

but

puts [nil, 1, 2]

gives

1
2

Note, no appearing nil item (just a blank line) and each item on a different line.

415 Unsupported Media Type - POST json to OData service in lightswitch 2012

It looks like this issue has to do with the difference between the Content-Type and Accept headers. In HTTP, Content-Type is used in request and response payloads to convey the media type of the current payload. Accept is used in request payloads to say what media types the server may use in the response payload.

So, having a Content-Type in a request without a body (like your GET request) has no meaning. When you do a POST request, you are sending a message body, so the Content-Type does matter.

If a server is not able to process the Content-Type of the request, it will return a 415 HTTP error. (If a server is not able to satisfy any of the media types in the request Accept header, it will return a 406 error.)

In OData v3, the media type "application/json" is interpreted to mean the new JSON format ("JSON light"). If the server does not support reading JSON light, it will throw a 415 error when it sees that the incoming request is JSON light. In your payload, your request body is verbose JSON, not JSON light, so the server should be able to process your request. It just doesn't because it sees the JSON light content type.

You could fix this in one of two ways:

  1. Make the Content-Type "application/json;odata=verbose" in your POST request, or
  2. Include the DataServiceVersion header in the request and set it be less than v3. For example:

    DataServiceVersion: 2.0;
    

(Option 2 assumes that you aren't using any v3 features in your request payload.)

How to check identical array in most efficient way?

You could compare String representations so:

array1.toString() == array2.toString()
array1.toString() !== array3.toString()

but that would also make

array4 = ['1',2,3,4,5]

equal to array1 if that matters to you

What characters are allowed in an email address?

As can be found in this Wikipedia link

The local-part of the email address may use any of these ASCII characters:

  • uppercase and lowercase Latin letters A to Z and a to z;

  • digits 0 to 9;

  • special characters !#$%&'*+-/=?^_`{|}~;

  • dot ., provided that it is not the first or last character unless quoted, and provided also that it does not appear consecutively unless quoted (e.g. [email protected] is not allowed but "John..Doe"@example.com is allowed);

  • space and "(),:;<>@[\] characters are allowed with restrictions (they are only allowed inside a quoted string, as described in the paragraph below, and in addition, a backslash or double-quote must be preceded by a backslash);

  • comments are allowed with parentheses at either end of the local-part; e.g. john.smith(comment)@example.com and (comment)[email protected] are both equivalent to [email protected].

In addition to the above ASCII characters, international characters above U+007F, encoded as UTF-8, are permitted by RFC 6531, though mail systems may restrict which characters to use when assigning local-parts.

A quoted string may exist as a dot separated entity within the local-part, or it may exist when the outermost quotes are the outermost characters of the local-part (e.g., abc."defghi"[email protected] or "abcdefghixyz"@example.com are allowed. Conversely, abc"defghi"[email protected] is not; neither is abc\"def\"[email protected]). Quoted strings and characters however, are not commonly used. RFC 5321 also warns that "a host that expects to receive mail SHOULD avoid defining mailboxes where the Local-part requires (or uses) the Quoted-string form".

The local-part postmaster is treated specially—it is case-insensitive, and should be forwarded to the domain email administrator. Technically all other local-parts are case-sensitive, therefore [email protected] and [email protected] specify different mailboxes; however, many organizations treat uppercase and lowercase letters as equivalent.

Despite the wide range of special characters which are technically valid; organisations, mail services, mail servers and mail clients in practice often do not accept all of them. For example, Windows Live Hotmail only allows creation of email addresses using alphanumerics, dot (.), underscore (_) and hyphen (-). Common advice is to avoid using some special characters to avoid the risk of rejected emails.

adb doesn't show nexus 5 device

For those who are still frustrated, if you are using the experimental ART runtime, try switching back to dalvik (in developer options on device)

How do I flush the PRINT buffer in TSQL?

Building on the answer by @JoelCoehoorn, my approach is to leave all my PRINT statements in place, and simply follow them with the RAISERROR statement to cause the flush.

For example:

PRINT 'MyVariableName: ' + @MyVariableName
RAISERROR(N'', 0, 1) WITH NOWAIT

The advantage of this approach is that the PRINT statements can concatenate strings, whereas the RAISERROR cannot. (So either way you have the same number of lines of code, as you'd have to declare and set a variable to use in RAISERROR).

If, like me, you use AutoHotKey or SSMSBoost or an equivalent tool, you can easily set up a shortcut such as "]flush" to enter the RAISERROR line for you. This saves you time if it is the same line of code every time, i.e. does not need to be customised to hold specific text or a variable.

How to upper case every first letter of word in a string?

package com.raj.samplestring;

/**
 * @author gnagara
 */
public class SampleString {

    /**
     * @param args
     */
    public static void main(String[] args) {
       String[] stringArray;
       String givenString = "ramu is Arr Good boy";

       stringArray = givenString.split(" ");


       for(int i=0; i<stringArray.length;i++){
           if(!Character.isUpperCase(stringArray[i].charAt(0))){
               Character c = stringArray[i].charAt(0);
               Character change = Character.toUpperCase(c);

               StringBuffer ss = new StringBuffer(stringArray[i]);
               ss.insert(0, change);
               ss.deleteCharAt(1);
               stringArray[i]= ss.toString();
           }
       }
       for(String e:stringArray){
           System.out.println(e);
      }
    }
}

Git: How to commit a manually deleted file?

The answer's here, I think.

It's better if you do git rm <fileName>, though.

Where is the php.ini file on a Linux/CentOS PC?

php -i |grep 'Configuration File'

How to use custom packages

another solution:
add src/myproject to $GOPATH.

Then import "mylib" will compile.

What is the difference between .NET Core and .NET Standard Class Library project types?

.NET and .NET Core are two different implementations of the .NET runtime. Both Core and Framework (but especially Framework) have different profiles that include larger or smaller (or just plain different) selections of the many APIs and assemblies Microsoft has created for .NET, depending on where they are installed and in what profile.

For example, there are some different APIs available in Universal Windows apps than in the "normal" Windows profile. Even on Windows, you might have the "Client" profile vs. the "Full" profile. Additionally, and there are other implementations (like Mono) that have their own sets of libraries.

.NET Standard is a specification for which sets of API libraries and assemblies must be available. An app written for .NET Standard 1.0 should be able to compile and run with any version of Framework, Core, Mono, etc., that advertises support for the .NET Standard 1.0 collection of libraries. Similar is true for .NET Standard 1.1, 1.5, 1.6, 2.0, etc. As long as the runtime provides support for the version of Standard targeted by your program, your program should run there.

A project targeted at a version of Standard will not be able to make use of features that are not included in that revision of the standard. This doesn't mean you can't take dependencies on other assemblies, or APIs published by other vendors (i.e.: items on NuGet). But it does mean that any dependencies you take must also include support for your version of .NET Standard. .NET Standard is evolving quickly, but it's still new enough, and cares enough about some of the smaller runtime profiles, that this limitation can feel stifling. (Note a year and a half later: this is starting to change, and recent .NET Standard versions are much nicer and more full-featured).

On the other hand, an app targeted at Standard should be able to be used in more deployment situations, since in theory it can run with Core, Framework, Mono, etc. For a class library project looking for wide distribution, that's an attractive promise. For a class library project used mainly for internal purposes, it may not be as much of a concern.

.NET Standard can also be useful in situations where the system administrator team is wanting to move from ASP.NET on Windows to ASP.NET for .NET Core on Linux for philosophical or cost reasons, but the Development team wants to continue working against .NET Framework in Visual Studio on Windows.

Facebook share button and custom text

you could combine AllisonC's idea with window.open function: http://www.w3schools.com/jsref/met_win_open.asp

function openWin(url) {
    myWindow = window.open(url, '', 'width=800,height=400');
    myWindow.focus();
}

And then on each link you call the openWin function with the right social net url.

JavaScript get clipboard data on paste event (Cross browser)

The situation has changed since writing this answer: now that Firefox has added support in version 22, all major browsers now support accessing the clipboard data in a paste event. See Nico Burns's answer for an example.

In the past this was not generally possible in a cross-browser way. The ideal would be to be able to get the pasted content via the paste event, which is possible in recent browsers but not in some older browsers (in particular, Firefox < 22).

When you need to support older browsers, what you can do is quite involved and a bit of a hack that will work in Firefox 2+, IE 5.5+ and WebKit browsers such as Safari or Chrome. Recent versions of both TinyMCE and CKEditor use this technique:

  1. Detect a ctrl-v / shift-ins event using a keypress event handler
  2. In that handler, save the current user selection, add a textarea element off-screen (say at left -1000px) to the document, turn designMode off and call focus() on the textarea, thus moving the caret and effectively redirecting the paste
  3. Set a very brief timer (say 1 millisecond) in the event handler to call another function that stores the textarea value, removes the textarea from the document, turns designMode back on, restores the user selection and pastes the text in.

Note that this will only work for keyboard paste events and not pastes from the context or edit menus. By the time the paste event fires, it's too late to redirect the caret into the textarea (in some browsers, at least).

In the unlikely event that you need to support Firefox 2, note that you'll need to place the textarea in the parent document rather than the WYSIWYG editor iframe's document in that browser.

How to write URLs in Latex?

Here is all the information you need in order to format clickable hyperlinks in LaTeX:

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

Essentially, you use the hyperref package and use the \url or \href tag depending on what you're trying to achieve.

How can I find the first and last date in a month using PHP?

You can use the date function to find how many days in a month there are.

// Get the timestamp for the date/month in question.
$ts = strtotime('April 2010');

echo date('t', $ts); 
// Result: 30, therefore, April 30, 2010 is the last day of that month.

Hope that helps.

EDIT: After reading Luis' answer, it occurred to me you may want it in the right format (YY-mm-dd). It may be obvious, but doesn't hurt to mention:

// After the above code
echo date('Y-m-t', $ts); 

"RuntimeError: Make sure the Graphviz executables are on your system's path" after installing Graphviz 2.38

Add graphviz to the System Path

  1. Windows - Edit the System Environment Variables.
  2. Choose Environment Variables.
  3. Select Path - New
  4. Add the Path of graphviz

Ex: C:\Users\AppData\Local\Continuum\anaconda3\Library\bin\graphviz

Unique on a dataframe with only selected columns

Here are a couple dplyr options that keep non-duplicate rows based on columns id and id2:

library(dplyr)                                        
df %>% distinct(id, id2, .keep_all = TRUE)
df %>% group_by(id, id2) %>% filter(row_number() == 1)
df %>% group_by(id, id2) %>% slice(1)

ROW_NUMBER() in MySQL

query for row_number in mysql

set @row_number=0;
select (@row_number := @row_number +1) as num,id,name from sbs

Creating threads - Task.Factory.StartNew vs new Thread()

The task gives you all the goodness of the task API:

  • Adding continuations (Task.ContinueWith)
  • Waiting for multiple tasks to complete (either all or any)
  • Capturing errors in the task and interrogating them later
  • Capturing cancellation (and allowing you to specify cancellation to start with)
  • Potentially having a return value
  • Using await in C# 5
  • Better control over scheduling (if it's going to be long-running, say so when you create the task so the task scheduler can take that into account)

Note that in both cases you can make your code slightly simpler with method group conversions:

DataInThread = new Thread(ThreadProcedure);
// Or...
Task t = Task.Factory.StartNew(ThreadProcedure);

Using the Underscore module with Node.js

The Node REPL uses the underscore variable to hold the result of the last operation, so it conflicts with the Underscore library's use of the same variable. Try something like this:

Admin-MacBook-Pro:test admin$ node
> _und = require("./underscore-min")
{ [Function]
  _: [Circular],
  VERSION: '1.1.4',
  forEach: [Function],
  each: [Function],
  map: [Function],
  inject: [Function],
  (...more functions...)
  templateSettings: { evaluate: /<%([\s\S]+?)%>/g, interpolate: /<%=([\s\S]+?)%>/g },
  template: [Function] }
> _und.max([1,2,3])
3
> _und.max([4,5,6])
6

Fetch frame count with ffmpeg

Not all formats store their frame count or total duration - and even if they do, the file might be incomplete - so ffmpeg doesn't detect either of them accurately by default.

Instead, try seeking to the end of the file and read the time, then count the current time while you go.

Alternatively, you can try AVFormatContext->nb_index_entries or the detected duration, which should work on fine at least undamaged AVI/MOV, or the library FFMS2, which is probably too slow to bother with for a progress bar.

error: expected primary-expression before ')' token (C)

You should create a variable of the type SelectionneNonSelectionne.

struct SelectionneNonSelectionne var;

After that pass that variable to the function like

characterSelection(screen, var);

The error is caused since you are passing the type name SelectionneNonSelectionne

Creating a textarea with auto-resize

This code works for pasting and select delete also.

_x000D_
_x000D_
onKeyPressTextMessage = function(){_x000D_
   var textArea = event.currentTarget;_x000D_
     textArea.style.height = 'auto';_x000D_
     textArea.style.height = textArea.scrollHeight + 'px';_x000D_
};
_x000D_
<textarea onkeyup="onKeyPressTextMessage(event)" name="welcomeContentTmpl" id="welcomeContent" onblur="onblurWelcomeTitle(event)" rows="2" cols="40" maxlength="320"></textarea>
_x000D_
_x000D_
_x000D_

Here is the JSFiddle

How to use __DATE__ and __TIME__ predefined macros in as two integers, then stringify?

You could always write a simple program in Python or something to create an include file that has simple #define statements with a build number, time, and date. You would then need to run this program before doing a build.

If you like I'll write one and post source here.

If you are lucky, your build tool (IDE or whatever) might have the ability to run an external command, and then you could have the external tool rewrite the include file automatically with each build.

EDIT: Here's a Python program. This writes a file called build_num.h and has an integer build number that starts at 1 and increments each time this program is run; it also writes #define values for the year, month, date, hours, minutes and seconds of the time this program is run. It also has a #define for major and minor parts of the version number, plus the full VERSION and COMPLETE_VERSION that you wanted. (I wasn't sure what you wanted for the date and time numbers, so I went for just concatenated digits from the date and time. You can change this easily.)

Each time you run it, it reads in the build_num.h file, and parses it for the build number; if the build_num.h file does not exist, it starts the build number at 1. Likewise it parses out major and minor version numbers, and if the file does not exist defaults those to version 0.1.

import time

FNAME = "build_num.h"

build_num = None
version_major = None
version_minor = None

DEF_BUILD_NUM = "#define BUILD_NUM "
DEF_VERSION_MAJOR = "#define VERSION_MAJOR "
DEF_VERSION_MINOR = "#define VERSION_MINOR "

def get_int(s_marker, line):
    _, _, s = line.partition(s_marker) # we want the part after the marker
    return int(s)

try:
    with open(FNAME) as f:
        for line in f:
            if DEF_BUILD_NUM in line:
                build_num = get_int(DEF_BUILD_NUM, line)
                build_num += 1
            elif DEF_VERSION_MAJOR in line:
                version_major = get_int(DEF_VERSION_MAJOR, line)
            elif DEF_VERSION_MINOR in line:
                version_minor = get_int(DEF_VERSION_MINOR, line)
except IOError:
    build_num = 1
    version_major = 0
    version_minor = 1

assert None not in (build_num, version_major, version_minor)


with open(FNAME, 'w') as f:
    f.write("#ifndef BUILD_NUM_H\n")
    f.write("#define BUILD_NUM_H\n")
    f.write("\n")
    f.write(DEF_BUILD_NUM + "%d\n" % build_num)
    f.write("\n")
    t = time.localtime()
    f.write("#define BUILD_YEAR %d\n" % t.tm_year)
    f.write("#define BUILD_MONTH %d\n" % t.tm_mon)
    f.write("#define BUILD_DATE %d\n" % t.tm_mday)
    f.write("#define BUILD_HOUR %d\n" % t.tm_hour)
    f.write("#define BUILD_MIN %d\n" % t.tm_min)
    f.write("#define BUILD_SEC %d\n" % t.tm_sec)
    f.write("\n")
    f.write("#define VERSION_MAJOR %d\n" % version_major)
    f.write("#define VERSION_MINOR %d\n" % version_minor)
    f.write("\n")
    f.write("#define VERSION \"%d.%d\"\n" % (version_major, version_minor))
    s = "%d.%d.%04d%02d%02d.%02d%02d%02d" % (version_major, version_minor,
            t.tm_year, t.tm_mon, t.tm_mday, t.tm_hour, t.tm_min, t.tm_sec)
    f.write("#define COMPLETE_VERSION \"%s\"\n" % s)
    f.write("\n")
    f.write("#endif // BUILD_NUM_H\n")

I made all the defines just be integers, but since they are simple integers you can use the standard stringizing tricks to build a string out of them if you like. Also you can trivially extend it to build additional pre-defined strings.

This program should run fine under Python 2.6 or later, including any Python 3.x version. You could run it under an old Python with a few changes, like not using .partition() to parse the string.

How to get image height and width using java?

You can load jpeg binary data as a file and parse the jpeg headers yourself. The one you are looking for is the 0xFFC0 or Start of Frame header:

Start of frame marker (FFC0)

* the first two bytes, the length, after the marker indicate the number of bytes, including the two length bytes, that this header contains
* P -- one byte: sample precision in bits (usually 8, for baseline JPEG)
* Y -- two bytes
* X -- two bytes
* Nf -- one byte: the number of components in the image
      o 3 for color baseline JPEG images
      o 1 for grayscale baseline JPEG images

* Nf times:
      o Component ID -- one byte
      o H and V sampling factors -- one byte: H is first four bits and V is second four bits
      o Quantization table number-- one byte

The H and V sampling factors dictate the final size of the component they are associated with. For instance, the color space defaults to YCbCr and the H and V sampling factors for each component, Y, Cb, and Cr, default to 2, 1, and 1, respectively (2 for both H and V of the Y component, etc.) in the Jpeg-6a library by the Independent Jpeg Group. While this does mean that the Y component will be twice the size of the other two components--giving it a higher resolution, the lower resolution components are quartered in size during compression in order to achieve this difference. Thus, the Cb and Cr components must be quadrupled in size during decompression.

For more info about the headers check out wikipedia's jpeg entry or I got the above info here.

I used a method similar to the code below which I got from this post at the sun forums:

import java.awt.Dimension;
import java.io.*;

public class JPEGDim {

public static Dimension getJPEGDimension(File f) throws IOException {
    FileInputStream fis = new FileInputStream(f);

    // check for SOI marker
    if (fis.read() != 255 || fis.read() != 216)
        throw new RuntimeException("SOI (Start Of Image) marker 0xff 0xd8 missing");

    Dimension d = null;

    while (fis.read() == 255) {
        int marker = fis.read();
        int len = fis.read() << 8 | fis.read();

        if (marker == 192) {
            fis.skip(1);

            int height = fis.read() << 8 | fis.read();
            int width = fis.read() << 8 | fis.read();

            d = new Dimension(width, height);
            break;
        }

        fis.skip(len - 2);
    }

    fis.close();

    return d;
}

public static void main(String[] args) throws IOException {
    System.out.println(getJPEGDimension(new File(args[0])));
}

}

How to resolve merge conflicts in Git repository?

git fetch <br>
git checkout **your branch**<br>
git rebase master<br>

In this step you will try to fix the conflict using your preferred IDE.

You can follow this link to check how to fix the conflict in the file

git add<br>
git rebase --continue<br>
git commit --amend<br>
git push origin HEAD:refs/drafts/master  (push like a drafts)<br>

Now everything is fine and you will find your commit in gerrit

I hope that this will help everyone concerning this issue.

How to show a running progress bar while page is loading

Simple Steps, follow them and i guess it will solve your problem

Include these Css in your page,

.progress {
      position: relative;
      height: 2px;
      display: block;
      width: 100%;
      background-color: white;
      border-radius: 2px;
      background-clip: padding-box;
      /*margin: 0.5rem 0 1rem 0;*/
      overflow: hidden;

    }
    .progress .indeterminate {
background-color:black; }
    .progress .indeterminate:before {
      content: '';
      position: absolute;
      background-color: #2C67B1;
      top: 0;
      left: 0;
      bottom: 0;
      will-change: left, right;
      -webkit-animation: indeterminate 2.1s cubic-bezier(0.65, 0.815, 0.735, 0.395) infinite;
              animation: indeterminate 2.1s cubic-bezier(0.65, 0.815, 0.735, 0.395) infinite; }
    .progress .indeterminate:after {
      content: '';
      position: absolute;
      background-color: #2C67B1;
      top: 0;
      left: 0;
      bottom: 0;
      will-change: left, right;
      -webkit-animation: indeterminate-short 2.1s cubic-bezier(0.165, 0.84, 0.44, 1) infinite;
              animation: indeterminate-short 2.1s cubic-bezier(0.165, 0.84, 0.44, 1) infinite;
      -webkit-animation-delay: 1.15s;
              animation-delay: 1.15s; }

    @-webkit-keyframes indeterminate {
      0% {
        left: -35%;
        right: 100%; }
      60% {
        left: 100%;
        right: -90%; }
      100% {
        left: 100%;
        right: -90%; } }
    @keyframes indeterminate {
      0% {
        left: -35%;
        right: 100%; }
      60% {
        left: 100%;
        right: -90%; }
      100% {
        left: 100%;
        right: -90%; } }
    @-webkit-keyframes indeterminate-short {
      0% {
        left: -200%;
        right: 100%; }
      60% {
        left: 107%;
        right: -8%; }
      100% {
        left: 107%;
        right: -8%; } }
    @keyframes indeterminate-short {
      0% {
        left: -200%;
        right: 100%; }
      60% {
        left: 107%;
        right: -8%; }
      100% {
        left: 107%;
        right: -8%; } }

Then include the progress bar your body tag,

<div class="progress" id="PreLoaderBar">
        <div class="indeterminate"></div>
    </div>

then it will start as your page loads, and now what you have to do is just hide this when the page loads,or set the visibility to none, or hidden, using javascript,

document.onreadystatechange = function () {
            if (document.readyState === "complete") {
                console.log(document.readyState);
                document.getElementById("PreLoaderBar").style.display = "none";
            }
        }

Let me Know if you face any problems and also, you can add any type of progress bar you can easily find them, for this example i have used a indeterminate progress bar.

How do I plot only a table in Matplotlib?

Not sure if this is already answered, but if you want only a table in a figure window, then you can hide the axes:

fig, ax = plt.subplots()

# Hide axes
ax.xaxis.set_visible(False) 
ax.yaxis.set_visible(False)

# Table from Ed Smith answer
clust_data = np.random.random((10,3))
collabel=("col 1", "col 2", "col 3")
ax.table(cellText=clust_data,colLabels=collabel,loc='center')

How do I get the total number of unique pairs of a set in the database?

TLDR; The formula is n(n-1)/2 where n is the number of items in the set.

Explanation:

To find the number of unique pairs in a set, where the pairs are subject to the commutative property (AB = BA), you can calculate the summation of 1 + 2 + ... + (n-1) where n is the number of items in the set.

The reasoning is as follows, say you have 4 items:

A
B
C
D

The number of items that can be paired with A is 3, or n-1:

AB
AC
AD

It follows that the number of items that can be paired with B is n-2 (because B has already been paired with A):

BC
BD

and so on...

(n-1) + (n-2) + ... + (n-(n-1))

which is the same as

1 + 2 + ... + (n-1)

or

n(n-1)/2

Getting the inputstream from a classpath resource (XML file)

Some of the "getResourceAsStream()" options in this answer didn't work for me, but this one did:

SomeClassWithinYourSourceDir.class.getClassLoader().getResourceAsStream("yourResource");

How to save data file into .RData?

There are three ways to save objects from your R session:

Saving all objects in your R session:

The save.image() function will save all objects currently in your R session:

save.image(file="1.RData") 

These objects can then be loaded back into a new R session using the load() function:

load(file="1.RData")

Saving some objects in your R session:

If you want to save some, but not all objects, you can use the save() function:

save(city, country, file="1.RData")

Again, these can be reloaded into another R session using the load() function:

load(file="1.RData") 

Saving a single object

If you want to save a single object you can use the saveRDS() function:

saveRDS(city, file="city.rds")
saveRDS(country, file="country.rds") 

You can load these into your R session using the readRDS() function, but you will need to assign the result into a the desired variable:

city <- readRDS("city.rds")
country <- readRDS("country.rds")

But this also means you can give these objects new variable names if needed (i.e. if those variables already exist in your new R session but contain different objects):

city_list <- readRDS("city.rds")
country_vector <- readRDS("country.rds")

Oracle find a constraint

select * from all_constraints
where owner = '<NAME>'
and constraint_name = 'SYS_C00381400'
/

Like all data dictionary views, this a USER_CONSTRAINTS view if you just want to check your current schema and a DBA_CONSTRAINTS view for administration users.

The construction of the constraint name indicates a system generated constraint name. For instance, if we specify NOT NULL in a table declaration. Or indeed a primary or unique key. For example:

SQL> create table t23 (id number not null primary key)
  2  /

Table created.

SQL> select constraint_name, constraint_type
  2  from user_constraints
  3  where table_name = 'T23'
  4  /

CONSTRAINT_NAME                C
------------------------------ -
SYS_C00935190                  C
SYS_C00935191                  P

SQL>

'C' for check, 'P' for primary.

Generally it's a good idea to give relational constraints an explicit name. For instance, if the database creates an index for the primary key (which it will do if that column is not already indexed) it will use the constraint name oo name the index. You don't want a database full of indexes named like SYS_C00935191.

To be honest most people don't bother naming NOT NULL constraints.

SQL recursive query on self referencing table (Oracle)

Use:

    SELECT t1.id, 
           t1.parent_id, 
           t1.name,
           t2.name AS parent_name,
           t2.id AS parent_id
      FROM tbl t1
 LEFT JOIN tbl t2 ON t2.id = t1.parent_id
START WITH t1.id = 1 
CONNECT BY PRIOR t1.id = t1.parent_id

Why catch and rethrow an exception in C#?

Rethrowing exceptions via throw is useful when you don't have a particular code to handle current exceptions, or in cases when you have a logic to handle specific error cases but want to skip all others.

Example:

string numberText = "";
try
{
    Console.Write("Enter an integer: ");
    numberText = Console.ReadLine();
    var result = int.Parse(numberText);

    Console.WriteLine("You entered {0}", result);
}
catch (FormatException)
{
    if (numberText.ToLowerInvariant() == "nothing")
    {
        Console.WriteLine("Please, please don't be lazy and enter a valid number next time.");
    }
    else
    {
        throw;
    }
}    
finally
{
    Console.WriteLine("Freed some resources.");
}
Console.ReadKey();

However, there is also another way of doing this, using conditional clauses in catch blocks:

string numberText = "";
try
{
    Console.Write("Enter an integer: ");
    numberText = Console.ReadLine();
    var result = int.Parse(numberText);

    Console.WriteLine("You entered {0}", result);
}
catch (FormatException) when (numberText.ToLowerInvariant() == "nothing")
{
    Console.WriteLine("Please, please don't be lazy and enter a valid number next time.");
}    
finally
{
    Console.WriteLine("Freed some resources.");
}
Console.ReadKey();

This mechanism is more efficient than re-throwing an exception because of the .NET runtime doesn’t have to rebuild the exception object before re-throwing it.

Render Partial View Using jQuery in ASP.NET MVC

I have used ajax load to do this:

$('#user_content').load('@Url.Action("UserDetails","User")');

Getting request payload from POST request in Java servlet

String payloadRequest = getBody(request);

Using this method

public static String getBody(HttpServletRequest request) throws IOException {

    String body = null;
    StringBuilder stringBuilder = new StringBuilder();
    BufferedReader bufferedReader = null;

    try {
        InputStream inputStream = request.getInputStream();
        if (inputStream != null) {
            bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            char[] charBuffer = new char[128];
            int bytesRead = -1;
            while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                stringBuilder.append(charBuffer, 0, bytesRead);
            }
        } else {
            stringBuilder.append("");
        }
    } catch (IOException ex) {
        throw ex;
    } finally {
        if (bufferedReader != null) {
            try {
                bufferedReader.close();
            } catch (IOException ex) {
                throw ex;
            }
        }
    }

    body = stringBuilder.toString();
    return body;
}

What is an example of the Liskov Substitution Principle?

I guess everyone kind of covered what LSP is technically: You basically want to be able to abstract away from subtype details and use supertypes safely.

So Liskov has 3 underlying rules:

  1. Signature Rule : There should be a valid implementation of every operation of the supertype in the subtype syntactically. Something a compiler will be able to check for you. There is a little rule about throwing fewer exceptions and being at least as accessible as the supertype methods.

  2. Methods Rule: The implementation of those operations is semantically sound.

    • Weaker Preconditions : The subtype functions should take at least what the supertype took as input, if not more.
    • Stronger Postconditions: They should produce a subset of the output the supertype methods produced.
  3. Properties Rule : This goes beyond individual function calls.

    • Invariants : Things that are always true must remain true. Eg. a Set's size is never negative.
    • Evolutionary Properties : Usually something to do with immutability or the kind of states the object can be in. Or maybe the object only grows and never shrinks so the subtype methods shouldn't make it.

All these properties need to be preserved and the extra subtype functionality shouldn't violate supertype properties.

If these three things are taken care of , you have abstracted away from the underlying stuff and you are writing loosely coupled code.

Source: Program Development in Java - Barbara Liskov

How to execute a bash command stored as a string with quotes and asterisk

try this

$ cmd='mysql AMORE -u root --password="password" -h localhost -e "select host from amoreconfig"'
$ eval $cmd

How do I include image files in Django templates?

Try this,

settings.py

# typically, os.path.join(os.path.dirname(__file__), 'media')
MEDIA_ROOT = '<your_path>/media'
MEDIA_URL = '/media/'

urls.py

urlpatterns = patterns('',
               (r'^media/(?P<path>.*)$', 'django.views.static.serve',
                 {'document_root': settings.MEDIA_ROOT}),
              )

.html

<img src="{{ MEDIA_URL }}<sub-dir-under-media-if-any>/<image-name.ext>" />

Caveat

Beware! using Context() will yield you an empty value for {{MEDIA_URL}}. You must use RequestContext(), instead.

I hope, this will help.

HTTP Status 405 - Method Not Allowed Error for Rest API

@Produces({"text/plain","application/xml","application/json"}) change this to @Produces("text/plain") and try,

Programmatically check Play Store for app updates

Update 17 October 2019

https://developer.android.com/guide/app-bundle/in-app-updates

Update 24 april 2019:

Android announced a feature which will probably fix this problem. Using the in-app Updates API: https://android-developers.googleblog.com/2018/11/unfolding-right-now-at-androiddevsummit.html

Original:

As far a I know, there is no official Google API which supports this.

You should consider to get a version number from an API.

Instead of connecting to external APIs or webpages (like Google Play Store). There is a risk that something may change in the API or the webpage, so you should consider to check if the version code of the current app is below the version number you get from your own API.

Just remember if you update your app, you need to change the version in your own API with the app version number.

I would recommend that you make a file in your own website or API, with the version number. (Eventually make a cronjob and make the version update automatic, and send a notification when something goes wrong)

You have to get this value from your Google Play Store page (is changed in the meantime, not working anymore):

<div class="content" itemprop="softwareVersion"> x.x.x  </div>

Check in your app if the version used on the mobile is below the version nummer showed on your own API.

Show indication that she/he needs to update with a notification, ideally.

Things you can do

Version number using your own API

Pros:

  • No need to load the whole code of the Google Play Store (saves on data/bandwidth)

Cons:

  • User can be offline, which makes checking useless since the API can't be accessed

Version number on webpage Google Play Store

Pros:

  • You don't need an API

Cons:

  • User can be offline, which makes checking useless since the API can't be accessed
    • Using this method may cost your users more bandwidth/mobile data
    • Play store webpage could change which makes your version 'ripper' not work anymore.

bootstrap button shows blue outline when clicked

Try this

.btn
{
    box-shadow: none;
    outline: none;
}

C# Public Enums in Classes

Just declare it outside class definition.

If your namespace's name is X, you will be able to access the enum's values by X.card_suit

If you have not defined a namespace for this enum, just call them by card_suit.Clubs etc.

How to put data containing double-quotes in string variable?

You can escape (this is how this principle is called) the double quotes by prefixing them with another double quote. You can put them in a string as follows:

Dim MyVar as string = "some text ""hello"" "

This will give the MyVar variable a value of some text "hello".

Temporarily change current working directory in bash to run a command

bash has a builtin

pushd SOME_PATH
run_stuff
...
...
popd 

make a header full screen (width) css

Remove the max-width from the body, and put it to the #container.

So, instead of:

body {
    max-width:1250px;
}

You should have:

#container {
    max-width:1250px;
}

How to auto-indent code in the Atom editor?

Package auto-indent exists to apply auto-indent to entire file with this shortcuts :

ctrl+shift+i

or

cmd+shift+i

Package url : https://atom.io/packages/auto-indent

How to set textColor of UILabel in Swift

solution for swift 3 -

let titleLabel = UILabel(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
titleLabel.text = "change to red color"
titleLabel.textAlignment = .center
titleLabel.textColor = UIColor.red

MVC 3: How to render a view without its layout page when loaded via ajax?

In ~/Views/ViewStart.cshtml:

@{
    Layout = Request.IsAjaxRequest() ? null : "~/Views/Shared/_Layout.cshtml";
}

and in the controller:

public ActionResult Index()
{
    return View();
}

Including non-Python files with setup.py

Figured out a workaround: I renamed my lgpl2.1_license.txt to lgpl2.1_license.txt.py, and put some triple quotes around the text. Now I don't need to use the data_files option nor to specify any absolute paths. Making it a Python module is ugly, I know, but I consider it less ugly than specifying absolute paths.

How do you easily horizontally center a <div> using CSS?

Using jQuery:

$(document).ready(function() {
    $(".myElement").wrap( '<span class="myElement_container_new"></span>' ); // for IE6
    $(".myElement_container_new").css({// for IE6
        "display" : "block",
        "position" : "relative",
        "margin" : "0",
        "padding" : "0",
        "border" : "none",
        "background-color" : "transparent",
        "clear" : "both",
        "text-align" : "center"
    });
    $(".myElement").css({
        "display" : "block",
        "position" : "relative",
        "max-width" : "75%", // for example
        "margin-left" : "auto",
        "margin-right" : "auto",
        "clear" : "both",
        "text-align" : "left"
    });
});

or, if you want to center every element with class ".myElement":

$(document).ready(function() {
    $(".myElement").each(function() {
        $(this).wrap( '<span class="myElement_container_new"></span>' ); // for IE6
        $(".myElement_container_new").css({// for IE6
            "display" : "block",
            "position" : "relative",
            "margin" : "0",
            "padding" : "0",
            "border" : "none",
            "background-color" : "transparent",
            "clear" : "both",
            "text-align" : "center"
        });
        $(this).css({
            "display" : "block",
            "position" : "relative",
            "max-width" : "75%",
            "margin-left" : "auto",
            "margin-right" : "auto",
            "clear" : "both",
            "text-align" : "left"
        });
    });
});

Can I catch multiple Java exceptions in the same catch clause?

If there is a hierarchy of exceptions you can use the base class to catch all subclasses of exceptions. In the degenerate case you can catch all Java exceptions with:

try {
   ...
} catch (Exception e) {
   someCode();
}

In a more common case if RepositoryException is the the base class and PathNotFoundException is a derived class then:

try {
   ...
} catch (RepositoryException re) {
   someCode();
} catch (Exception e) {
   someCode();
}

The above code will catch RepositoryException and PathNotFoundException for one kind of exception handling and all other exceptions are lumped together. Since Java 7, as per @OscarRyz's answer above:

try { 
  ...
} catch( IOException | SQLException ex ) { 
  ...
}

How to add a TextView to a LinearLayout dynamically in Android?

LayoutParams lparams = new LayoutParams(
   LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
TextView tv=new TextView(this);
tv.setLayoutParams(lparams);
tv.setText("test");
this.m_vwJokeLayout.addView(tv);

You can change lparams according to your needs

How do I turn a C# object into a JSON string in .NET?

Wooou! Really better using a JSON framework :)

Here is my example using Json.NET (http://james.newtonking.com/json):

using System;
using System.Collections.Generic;
using System.Text;
using Newtonsoft.Json;
using System.IO;

namespace com.blogspot.jeanjmichel.jsontest.model
{
    public class Contact
    {
        private Int64 id;
        private String name;
        List<Address> addresses;

        public Int64 Id
        {
            set { this.id = value; }
            get { return this.id; }
        }

        public String Name
        {
            set { this.name = value; }
            get { return this.name; }
        }

        public List<Address> Addresses
        {
            set { this.addresses = value; }
            get { return this.addresses; }
        }

        public String ToJSONRepresentation()
        {
            StringBuilder sb = new StringBuilder();
            JsonWriter jw = new JsonTextWriter(new StringWriter(sb));

            jw.Formatting = Formatting.Indented;
            jw.WriteStartObject();
            jw.WritePropertyName("id");
            jw.WriteValue(this.Id);
            jw.WritePropertyName("name");
            jw.WriteValue(this.Name);

            jw.WritePropertyName("addresses");
            jw.WriteStartArray();

            int i;
            i = 0;

            for (i = 0; i < addresses.Count; i++)
            {
                jw.WriteStartObject();
                jw.WritePropertyName("id");
                jw.WriteValue(addresses[i].Id);
                jw.WritePropertyName("streetAddress");
                jw.WriteValue(addresses[i].StreetAddress);
                jw.WritePropertyName("complement");
                jw.WriteValue(addresses[i].Complement);
                jw.WritePropertyName("city");
                jw.WriteValue(addresses[i].City);
                jw.WritePropertyName("province");
                jw.WriteValue(addresses[i].Province);
                jw.WritePropertyName("country");
                jw.WriteValue(addresses[i].Country);
                jw.WritePropertyName("postalCode");
                jw.WriteValue(addresses[i].PostalCode);
                jw.WriteEndObject();
            }

            jw.WriteEndArray();

            jw.WriteEndObject();

            return sb.ToString();
        }

        public Contact()
        {
        }

        public Contact(Int64 id, String personName, List<Address> addresses)
        {
            this.id = id;
            this.name = personName;
            this.addresses = addresses;
        }

        public Contact(String JSONRepresentation)
        {
            //To do
        }
    }
}

The test:

using System;
using System.Collections.Generic;
using com.blogspot.jeanjmichel.jsontest.model;

namespace com.blogspot.jeanjmichel.jsontest.main
{
    public class Program
    {
        static void Main(string[] args)
        {
            List<Address> addresses = new List<Address>();
            addresses.Add(new Address(1, "Rua Dr. Fernandes Coelho, 85", "15º andar", "São Paulo", "São Paulo", "Brazil", "05423040"));
            addresses.Add(new Address(2, "Avenida Senador Teotônio Vilela, 241", null, "São Paulo", "São Paulo", "Brazil", null));

            Contact contact = new Contact(1, "Ayrton Senna", addresses);

            Console.WriteLine(contact.ToJSONRepresentation());
            Console.ReadKey();
        }
    }
}

The result:

{
  "id": 1,
  "name": "Ayrton Senna",
  "addresses": [
    {
      "id": 1,
      "streetAddress": "Rua Dr. Fernandes Coelho, 85",
      "complement": "15º andar",
      "city": "São Paulo",
      "province": "São Paulo",
      "country": "Brazil",
      "postalCode": "05423040"
    },
    {
      "id": 2,
      "streetAddress": "Avenida Senador Teotônio Vilela, 241",
      "complement": null,
      "city": "São Paulo",
      "province": "São Paulo",
      "country": "Brazil",
      "postalCode": null
    }
  ]
}

Now I will implement the constructor method that will receives a JSON string and populates the class' fields.

What is a elegant way in Ruby to tell if a variable is a Hash or an Array?

You can just do:

@some_var.class == Hash

or also something like:

@some_var.is_a?(Hash)

It's worth noting that the "is_a?" method is true if the class is anywhere in the objects ancestry tree. for instance:

@some_var.is_a?(Object)  # => true

the above is true if @some_var is an instance of a hash or other class that stems from Object. So, if you want a strict match on the class type, using the == or instance_of? method is probably what you're looking for.

How to determine if binary tree is balanced?

#include <iostream>
#include <deque>
#include <queue>

struct node
{
    int data;
    node *left;
    node *right;
};

bool isBalanced(node *root)
{
    if ( !root)
    {
        return true;
    }

    std::queue<node *> q1;
    std::queue<int>  q2;
    int level = 0, last_level = -1, node_count = 0;

    q1.push(root);
    q2.push(level);

    while ( !q1.empty() )
    {
        node *current = q1.front();
        level = q2.front();

        q1.pop();
        q2.pop();

        if ( level )
        {
            ++node_count;
        }

                if ( current->left )
                {
                        q1.push(current->left);
                        q2.push(level + 1);
                }

                if ( current->right )
                {
                        q1.push(current->right);
                        q2.push(level + 1);
                }

        if ( level != last_level )
        {
            std::cout << "Check: " << (node_count ? node_count - 1 : 1) << ", Level: " << level << ", Old level: " << last_level << std::endl;
            if ( level && (node_count - 1) != (1 << (level-1)) )
            {
                return false;
            }

            last_level = q2.front();
            if ( level ) node_count = 1;
        }
    }

    return true;
}

int main()
{
    node tree[15];

    tree[0].left  = &tree[1];
    tree[0].right = &tree[2];
    tree[1].left  = &tree[3];
    tree[1].right = &tree[4];
    tree[2].left  = &tree[5];
    tree[2].right = &tree[6];
    tree[3].left  = &tree[7];
    tree[3].right = &tree[8];
    tree[4].left  = &tree[9];   // NULL;
    tree[4].right = &tree[10];  // NULL;
    tree[5].left  = &tree[11];  // NULL;
    tree[5].right = &tree[12];  // NULL;
    tree[6].left  = &tree[13];
    tree[6].right = &tree[14];
    tree[7].left  = &tree[11];
    tree[7].right = &tree[12];
    tree[8].left  = NULL;
    tree[8].right = &tree[10];
    tree[9].left  = NULL;
    tree[9].right = &tree[10];
    tree[10].left = NULL;
    tree[10].right= NULL;
    tree[11].left = NULL;
    tree[11].right= NULL;
    tree[12].left = NULL;
    tree[12].right= NULL;
    tree[13].left = NULL;
    tree[13].right= NULL;
    tree[14].left = NULL;
    tree[14].right= NULL;

    std::cout << "Result: " << isBalanced(tree) << std::endl;

    return 0;
}

Java - checking if parseInt throws exception

instead of trying & catching expressions.. its better to run regex on the string to ensure that it is a valid number..

Semaphore vs. Monitors - what's the difference?

Semaphore allows multiple threads (up to a set number) to access a shared object. Monitors allow mutually exclusive access to a shared object.

Monitor

Semaphore

#ifdef replacement in the Swift language

This builds on Jon Willis's answer that relies upon assert, which only gets executed in Debug compilations:

func Log(_ str: String) { 
    assert(DebugLog(str)) 
}
func DebugLog(_ str: String) -> Bool { 
    print(str) 
    return true
}

My use case is for logging print statements. Here is a benchmark for Release version on iPhone X:

let iterations = 100_000_000
let time1 = CFAbsoluteTimeGetCurrent()
for i in 0 ..< iterations {
    Log ("? unarchiveArray:\(fileName) memoryTime:\(memoryTime) count:\(array.count)")
}
var time2 = CFAbsoluteTimeGetCurrent()
print ("Log: \(time2-time1)" )

prints:

Log: 0.0

Looks like Swift 4 completely eliminates the function call.

White space showing up on right side of page when background image should extend full length of page

I added:

html,body
{
    width: 100%;
    height: 100%;
    margin: 0px;
    padding: 0px;
    overflow-x: hidden; 
}

into your CSS at the very top above the other classes and it seemed to fix your issue.

Your updated .css file is available here

How to resize an image to fit in the browser window?

My general lazy CSS rule:

.background{
width:100%;
height:auto;
background: url('yoururl.jpg') no-repeat center;
background-position: 50% 50%;
background-size: 100% cover!important;
overflow:hidden;
}

This may zoom in on your image if it is low-res to begin with (that's to do with your image quality and size in dimensions. To center your image, you may also try (in the CSS)

display:block;    
margin: auto 0; 

to center your image

in your HTML:

<div class="background"></div>

SQL Update with row_number()

With UpdateData  As
(
SELECT RS_NOM,
ROW_NUMBER() OVER (ORDER BY [RS_NOM] DESC) AS RN
FROM DESTINATAIRE_TEMP
)
UPDATE DESTINATAIRE_TEMP SET CODE_DEST = RN
FROM DESTINATAIRE_TEMP
INNER JOIN UpdateData ON DESTINATAIRE_TEMP.RS_NOM = UpdateData.RS_NOM

How to import Google Web Font in CSS file?

Use the tag @import

@import url('http://fonts.googleapis.com/css?family=Kavoon');

PyCharm import external library

In order to reference an external library in a project File -> Settings -> Project -> Project structure -> select the folder and mark as a source

Select where count of one field is greater than one

You can also do this with a self-join:

SELECT t1.* FROM db.table t1
JOIN db.table t2 ON t1.someField = t2.someField AND t1.pk != t2.pk

top -c command in linux to filter processes listed based on processname

After looking for so many answers on StackOverflow, I haven't seen an answer to fit my needs.

That is, to make top command to keep refreshing with given keyword, and we don't have to CTRL+C / top again and again when new processes spawn.

Thus I make a new one...

Here goes the no-restart-needed version.

__keyword=name_of_process; (while :; do __arg=$(pgrep -d',' -f $__keyword); if [ -z "$__arg" ]; then top -u 65536 -n 1; else top -c -n 1 -p $__arg; fi; sleep 1; done;)

Modify the __keyword and it should works. (Ubuntu 2.6.38 tested)

2.14.2015 added: The system workload part is missing with the code above. For people who cares about the "load average" part:

__keyword=name_of_process; (while :; do __arg=$(pgrep -d',' -f $__keyword); if [ -z "$__arg" ]; then top -u 65536 -n 1; else top -c -n 1 -p $__arg; fi; uptime; sleep 1; done;)

How to listen for changes to a MongoDB collection?

What you are thinking of sounds a lot like triggers. MongoDB does not have any support for triggers, however some people have "rolled their own" using some tricks. The key here is the oplog.

When you run MongoDB in a Replica Set, all of the MongoDB actions are logged to an operations log (known as the oplog). The oplog is basically just a running list of the modifications made to the data. Replicas Sets function by listening to changes on this oplog and then applying the changes locally.

Does this sound familiar?

I cannot detail the whole process here, it is several pages of documentation, but the tools you need are available.

First some write-ups on the oplog - Brief description - Layout of the local collection (which contains the oplog)

You will also want to leverage tailable cursors. These will provide you with a way to listen for changes instead of polling for them. Note that replication uses tailable cursors, so this is a supported feature.

How to break/exit from a each() function in JQuery?

Return false from the anonymous function:

$(xml).find("strengths").each(function() {
  // Code
  // To escape from this block based on a condition:
  if (something) return false;
});

From the documentation of the each method:

Returning 'false' from within the each function completely stops the loop through all of the elements (this is like using a 'break' with a normal loop). Returning 'true' from within the loop skips to the next iteration (this is like using a 'continue' with a normal loop).

How to capture and save an image using custom camera in Android?

 showbookimage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                // create intent with ACTION_IMAGE_CAPTURE action
                Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                /**
 Here REQUEST_IMAGE is the unique integer value you can pass it any integer
 **/
                // start camera activity
                startActivityForResult(intent, TAKE_PICTURE);
            }

            }

        );

then u can now give the image a file name as follows and then convert it into bitmap and later on to file

 private void createImageFile(Bitmap bitmap) throws IOException {
        // Create an image file name
        ByteArrayOutputStream bytes = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.JPEG, 40, bytes);
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        String imageFileName = "JPEG_" + timeStamp + "_";
        File storageDir = Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES);
        File image = File.createTempFile(
                imageFileName,  /* prefix */
                ".jpg",         /* suffix */
                storageDir      /* directory */
        );
        FileOutputStream stream = new FileOutputStream(image);
        stream.write(bytes.toByteArray());
        stream.close();
        // Save a file: path for use with ACTION_VIEW intents
        mCurrentPhotoPath = "file:" + image.getAbsolutePath();
        fileUri = image.getAbsolutePath();
        Picasso.with(getActivity()).load(image).into(showbookimage);
    }
    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent intent) {

        if (requestCode == TAKE_PICTURE && resultCode== Activity.RESULT_OK && intent != null){
            // get bundle
            Bundle extras = intent.getExtras();
            // get
            bitMap = (Bitmap) extras.get("data");
//            showbookimage.setImageBitmap(bitMap);
            try {
                createImageFile(bitMap);
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    }

use picasso for images to display rather fast

Selenium: WebDriverException:Chrome failed to start: crashed as google-chrome is no longer running so ChromeDriver is assuming that Chrome has crashed

I had a similar issue, and discovered that option arguments must be in a certain order. I am only aware of the two arguments that were required to get this working on my Ubuntu 18 machine. This sample code worked on my end:

from selenium import webdriver
from selenium.webdriver.chrome.options import Options

options = Options()
options.add_argument('--no-sandbox')
options.add_argument('--disable-dev-shm-usage')

d = webdriver.Chrome(executable_path=r'/home/PycharmProjects/chromedriver', chrome_options=options)
d.get('https://www.google.nl/')

Best way to find if an item is in a JavaScript array?

First, implement indexOf in JavaScript for browsers that don't already have it. For example, see Erik Arvidsson's array extras (also, the associated blog post). And then you can use indexOf without worrying about browser support. Here's a slightly optimised version of his indexOf implementation:

if (!Array.prototype.indexOf) {
    Array.prototype.indexOf = function (obj, fromIndex) {
        if (fromIndex == null) {
            fromIndex = 0;
        } else if (fromIndex < 0) {
            fromIndex = Math.max(0, this.length + fromIndex);
        }
        for (var i = fromIndex, j = this.length; i < j; i++) {
            if (this[i] === obj)
                return i;
        }
        return -1;
    };
}

It's changed to store the length so that it doesn't need to look it up every iteration. But the difference isn't huge. A less general purpose function might be faster:

var include = Array.prototype.indexOf ?
    function(arr, obj) { return arr.indexOf(obj) !== -1; } :
    function(arr, obj) {
        for(var i = -1, j = arr.length; ++i < j;)
            if(arr[i] === obj) return true;
        return false;
    };

I prefer using the standard function and leaving this sort of micro-optimization for when it's really needed. But if you're keen on micro-optimization I adapted the benchmarks that roosterononacid linked to in the comments, to benchmark searching in arrays. They're pretty crude though, a full investigation would test arrays with different types, different lengths and finding objects that occur in different places.

How to create a DataFrame of random integers with Pandas?

numpy.random.randint accepts a third argument (size) , in which you can specify the size of the output array. You can use this to create your DataFrame -

df = pd.DataFrame(np.random.randint(0,100,size=(100, 4)), columns=list('ABCD'))

Here - np.random.randint(0,100,size=(100, 4)) - creates an output array of size (100,4) with random integer elements between [0,100) .


Demo -

import numpy as np
import pandas as pd
df = pd.DataFrame(np.random.randint(0,100,size=(100, 4)), columns=list('ABCD'))

which produces:

     A   B   C   D
0   45  88  44  92
1   62  34   2  86
2   85  65  11  31
3   74  43  42  56
4   90  38  34  93
5    0  94  45  10
6   58  23  23  60
..  ..  ..  ..  ..

SSRS 2008 R2 - SSRS 2012 - ReportViewer: Reports are blank in Safari and Chrome

I am using Chrome version 21 with SQL 2008 R2 SP1 and none of the above fixes worked for me. Below is the code that did work, as with the other answers I added this bit of code to Append to "C:\Program Files\Microsoft SQL Server\MSRS10_50.MSSQLSERVER\Reporting Services\ReportManager\js\ReportingServices.js" (on the SSRS Server) :

//Fix to allow Chrome to display SSRS Reports
function pageLoad() { 
    var element = document.getElementById("ctl31_ctl09");
    if (element) 
    {
        element.style.overflow = "visible";         
    } 
}

HTML checkbox onclick called in Javascript

How about putting the checkbox into the label, making the label automatically "click sensitive" for the check box, and giving the checkbox a onchange event?

<label ..... ><input type="checkbox" onchange="toggleCheckbox(this)" .....> 

function toggleCheckbox(element)
 {
   element.checked = !element.checked;
 }

This will additionally catch users using a keyboard to toggle the check box, something onclick would not.

When is the init() function run?

A few more tips:

  • There can only be 1 main() function, but there can be many init() functions.
  • You do not need to explicitly call init() or main(), they are called automatically.
  • init() and main() do not accept any parameters and also don't return anything.
  • init() runs before main().
  • If you have many init(), they run in the order they are declared.

How can I delete a file from a Git repository?

In my case I tried to remove file on github after few commits but save on computer

git filter-branch -f --index-filter 'git rm --cached --ignore-unmatch file_name_with_path' HEAD
git push --force -u origin master

and later this file was ignored

var self = this?

This question is not specific to jQuery, but specific to JavaScript in general. The core problem is how to "channel" a variable in embedded functions. This is the example:

var abc = 1; // we want to use this variable in embedded functions

function xyz(){
  console.log(abc); // it is available here!
  function qwe(){
    console.log(abc); // it is available here too!
  }
  ...
};

This technique relies on using a closure. But it doesn't work with this because this is a pseudo variable that may change from scope to scope dynamically:

// we want to use "this" variable in embedded functions

function xyz(){
  // "this" is different here!
  console.log(this); // not what we wanted!
  function qwe(){
    // "this" is different here too!
    console.log(this); // not what we wanted!
  }
  ...
};

What can we do? Assign it to some variable and use it through the alias:

var abc = this; // we want to use this variable in embedded functions

function xyz(){
  // "this" is different here! --- but we don't care!
  console.log(abc); // now it is the right object!
  function qwe(){
    // "this" is different here too! --- but we don't care!
    console.log(abc); // it is the right object here too!
  }
  ...
};

this is not unique in this respect: arguments is the other pseudo variable that should be treated the same way — by aliasing.

Fastest way to copy a file in Node.js

You may want to use async/await, since node v10.0.0 it's possible with the built-in fs Promises API.

Example:

const fs = require('fs')

const copyFile = async (src, dest) => {
  await fs.promises.copyFile(src, dest)
}

Note:

As of node v11.14.0, v10.17.0 the API is no longer experimental.

More information:

Promises API

Promises copyFile

Console output in a Qt GUI app?

One solution is to run powershell and redirect the output to whatever stream you want.

Below is an example of running powershell from cmd.exe and redirecting my_exec.exe output to both the console and an output.txt file:

powershell ".\my_exec.exe | tee output.txt"

DateTime.TryParse issue with dates of yyyy-dd-MM format

DateTime dt = DateTime.ParseExact("11-22-2012 12:00 am", "MM-dd-yyyy hh:mm tt", System.Globalization.CultureInfo.InvariantCulture);

Android Studio 3.0 Execution failed for task: unable to merge dex

Try to add this in gradle

    android {
      defaultConfig {
        multiDexEnabled true
        }
   }

Different ways of clearing lists

There are two cases in which you might want to clear a list:

  1. You want to use the name old_list further in your code;
  2. You want the old list to be garbage collected as soon as possible to free some memory;

In case 1 you just go on with the assigment:

    old_list = []    # or whatever you want it to be equal to

In case 2 the del statement would reduce the reference count to the list object the name old list points at. If the list object is only pointed by the name old_list at, the reference count would be 0, and the object would be freed for garbage collection.

    del old_list

How do I use CSS with a ruby on rails application?

To add to the above, the most obvious place to add stylesheet_link_tag is in your global application layout - application.html.erb.

Maven:Failed to execute goal org.apache.maven.plugins:maven-resources-plugin:2.7:resources

I had this issue too because I was filtering /src/main/resources and forgot I had added a keystore (*.jks) binary to this directory.

Add a "resource" block with exclusions for binary files and your problem may be resolved.

<build>
  <finalName>somename</finalName>
  <testResources>
    <testResource>
      <directory>src/test/resources</directory>
      <filtering>false</filtering>
    </testResource>
  </testResources>
  <resources>
    <resource>
      <directory>src/main/resources</directory>
      <filtering>true</filtering>
      <excludes>
        <exclude>*.jks</exclude>
        <exclude>*.png</exclude>
      </excludes>        
    </resource>
  </resources>
...

jQuery - passing value from one input to another

It's simpler if you modify your HTML a little bit:

<label for="first_name">First Name</label>
<input type="text" id="name" name="name" />

<label for="surname">Surname</label>
<input type="text" id="surname" name="surname" />

<label for="firstname">Firstname</label>
<input type="text" id="firstname" name="firstname" disabled="disabled" />

then it's relatively simple

$(document).ready(function() { 
    $('#name').change(function() {
      $('#firstname').val($('#name').val());
    });
});

org.xml.sax.SAXParseException: Premature end of file for *VALID* XML

This exception only happens if you are parsing an empty String/empty byte array.

below is a snippet on how to reproduce it:

String xml = ""; // <-- deliberately an empty string.
ByteArrayInputStream xmlStream = new java.io.ByteArrayInputStream(xml.getBytes());
Unmarshaller u = JAXBContext.newInstance(...)
u.setSchema(...);
u.unmarshal( xmlStream ); // <-- here it will fail

How do I set up the database.yml file in Rails?

The database.yml is the file where you set up all the information to connect to the database. It differs depending on the kind of DB you use. You can find more information about this in the Rails Guide or any tutorial explaining how to setup a rails project.

The information in the database.yml file is scoped by environment, allowing you to get a different setting for testing, development or production. It is important that you keep those distinct if you don't want the data you use for development deleted by mistake while running your test suite.

Regarding source control, you should not commit this file but instead create a template file for other developers (called database.yml.template). When deploying, the convention is to create this database.yml file in /shared/config directly on the server.

With SVN: svn propset svn:ignore config "database.yml"

With Git: Add config/database.yml to the .gitignore file or with git-extra git ignore config/database.yml


... and now, some examples:

SQLite

adapter: sqlite3
database: db/db_dev_db.sqlite3
pool: 5
timeout: 5000

MYSQL

adapter: mysql
database: my_db
hostname: 127.0.0.1
username: root
password: 
socket: /tmp/mysql.sock
pool: 5
timeout: 5000

MongoDB with MongoID (called mongoid.yml, but basically the same thing)

host: <%= ENV['MONGOID_HOST'] %>
port: <%= ENV['MONGOID_PORT'] %>
username: <%= ENV['MONGOID_USERNAME'] %>
password: <%= ENV['MONGOID_PASSWORD'] %>
database: <%= ENV['MONGOID_DATABASE'] %>
# slaves:
#   - host: slave1.local
#     port: 27018
#   - host: slave2.local
#     port: 27019

How can I simulate a click to an anchor tag?

Quoted from https://developer.mozilla.org/en/DOM/element.click

The click method is intended to be used with INPUT elements of type button, checkbox, radio, reset or submit. Gecko does not implement the click method on other elements that might be expected to respond to mouse–clicks such as links (A elements), nor will it necessarily fire the click event of other elements.

Non–Gecko DOMs may behave differently.

Unfortunately it sounds like you have already discovered the best solution to your problem.

As a side note, I agree that your solution seems less than ideal, but if you encapsulate the functionality inside a method (much like JQuery would do) it is not so bad.

I get exception when using Thread.sleep(x) or wait()

Use the following coding construct to handle exceptions

try {
  Thread.sleep(1000);
} catch (InterruptedException ie) {
    //Handle exception
}

Docker: How to use bash with an Alpine based docker image?

To Install bash you can do:

RUN apk add --update bash && rm -rf /var/cache/apk/*

If you do not want to add extra size to your image, you can use ash or sh that ships with alpine.

Reference: https://github.com/smebberson/docker-alpine/issues/43

Unable to launch the IIS Express Web server, Failed to register URL, Access is denied

I also read the answers and comments and tried some solutions from this thread.

Then a Googled a little more and this worked for me

https://www.c-sharpcorner.com/blogs/iis-express-failed-to-register-url-access-is-denied

Didn't comment on no one's answer because I didn't read whats written here, so it needed a new answer post. There's answers here that talk about netsh wlan stuff, but I didn't see exactly this solution. If some one wrote the exact same solution please tell me so I can comment there and remove this.

Clicking a button within a form causes page refresh

I also had the same problem, but gladelly I fixed this by changing the type like from type="submit" to type="button" and it worked.

UIView bottom border?

I wrote a general method that will add a border on whichever sides you wish in any UIView. You can define thickness, color, margins and zOrder for each side.

/*
 view: the view to draw border around
 thickness: thickness of the border on the given side
 color: color of the border on the given side
 margin: space between the border's outer edge and the view's frame edge on the given side.
 zOrder: defines the order to add the borders to the view.  The borders will be added by zOrder from lowest to highest, thus making the highest priority border visible when two borders overlap at the corners.
*/

    +(void) drawBorderAroundUIView:(UIView *) view thicknessLeft:(CGFloat) thicknessLeft colorLeft:(UIColor *)colorLeft marginLeft:(CGFloat) marginLeft zOrderLeft:(int) zOrderLeft thicknessRight:(CGFloat) thicknessRight colorRight:(UIColor *)colorRight marginRight:(CGFloat) marginRight zOrderRight:(int) zOrderRight thicknessTop:(CGFloat) thicknessTop colorTop:(UIColor *)colorTop marginTop:(CGFloat) marginTop zOrderTop:(int) zOrderTop thicknessBottom:(CGFloat) thicknessBottom colorBottom:(UIColor *)colorBottom marginBottom:(CGFloat) marginBottom zOrderBottom:(int) zOrderBottom{
    //make margins be the outside edge and make positive margin represent a smaller rectangle
    marginBottom = -1 * marginBottom - thicknessBottom;
    marginTop = -1 * marginTop - thicknessTop;
    marginLeft = -1 * marginLeft - thicknessLeft;
    marginRight = -1 * marginRight - thicknessRight;

    //get reference points for corners
    CGPoint upperLeftCorner = CGPointZero;
    CGPoint lowerLeftCorner = CGPointMake(upperLeftCorner.x, upperLeftCorner.y + view.frame.size.height);
    CGPoint upperRightCorner = CGPointMake(upperLeftCorner.x + view.frame.size.width, upperLeftCorner.y);

    //left
    CALayer *leftBorder = [CALayer layer];
    leftBorder.frame = CGRectMake(upperLeftCorner.x - thicknessLeft - marginLeft, upperLeftCorner.y - thicknessTop - marginTop, thicknessLeft, view.frame.size.height + marginTop + marginBottom + thicknessBottom + thicknessTop);
    leftBorder.backgroundColor = colorLeft.CGColor;

    //right
    CALayer *rightBorder = [CALayer layer];
    rightBorder.frame = CGRectMake(upperRightCorner.x + marginRight, upperRightCorner.y - thicknessTop - marginTop, thicknessRight, view.frame.size.height + marginTop + marginBottom + thicknessBottom + thicknessTop);
    rightBorder.backgroundColor = colorRight.CGColor;

    //top
    CALayer *topBorder = [CALayer layer];
    topBorder.frame = CGRectMake(upperLeftCorner.x - thicknessLeft - marginLeft, upperLeftCorner.y - thicknessTop - marginTop, view.frame.size.width + marginLeft + marginRight + thicknessLeft + thicknessRight, thicknessTop);
    topBorder.backgroundColor = colorTop.CGColor;

    //bottom
    CALayer *bottomBorder = [CALayer layer];
    bottomBorder.frame = CGRectMake(upperLeftCorner.x - thicknessLeft - marginLeft, lowerLeftCorner.y + marginBottom, view.frame.size.width + marginLeft + marginRight + thicknessLeft + thicknessRight, thicknessBottom);
    bottomBorder.backgroundColor = colorBottom.CGColor;

    //define dictionary keys to be used for adding borders in order of zOrder
    NSString *borderDK = @"border";
    NSString *zOrderDK = @"zOrder";

    //storing borders in dictionaries in preparation to add them in order of zOrder
    NSDictionary *leftBorderDictionary = [NSDictionary dictionaryWithObjectsAndKeys:leftBorder, borderDK, [NSNumber numberWithInt:zOrderLeft], zOrderDK, nil];
    NSDictionary *rightBorderDictionary = [NSDictionary dictionaryWithObjectsAndKeys:rightBorder, borderDK, [NSNumber numberWithInt:zOrderRight], zOrderDK, nil];
    NSDictionary *topBorderDictionary = [NSDictionary dictionaryWithObjectsAndKeys:topBorder, borderDK, [NSNumber numberWithInt:zOrderTop], zOrderDK, nil];
    NSDictionary *bottomBorderDictionary = [NSDictionary dictionaryWithObjectsAndKeys:bottomBorder, borderDK, [NSNumber numberWithInt:zOrderBottom], zOrderDK, nil];

    NSMutableArray *borders = [NSMutableArray arrayWithObjects:leftBorderDictionary, rightBorderDictionary, topBorderDictionary, bottomBorderDictionary, nil];

    //add borders in order of zOrder (lowest -> highest).  Thus the highest zOrder will be added last so it will be on top.
    while (borders.count)
    {
        //look for the next lowest zOrder border to add
        NSDictionary *nextBorderToLayDown = [borders objectAtIndex:0];
        for (int indexOfBorder = 0; indexOfBorder < borders.count; indexOfBorder++)
        {
            NSDictionary *borderAtIndex = [borders objectAtIndex:indexOfBorder];
            if ([[borderAtIndex objectForKey:zOrderDK] intValue] < [[nextBorderToLayDown objectForKey:zOrderDK] intValue])
            {
                nextBorderToLayDown = borderAtIndex;
            }
        }
        //add the border to the view
        [view.layer addSublayer:[nextBorderToLayDown objectForKey:borderDK]];
        [borders removeObject:nextBorderToLayDown];
    }
}

How to use multiple databases in Laravel

Laravel has inbuilt support for multiple database systems, you need to provide connection details in config/database.php file

return [
    'default' => env('DB_CONNECTION', 'mysql'),

    'connections' => [
        'mysql' => [
            'driver' => 'mysql',
            'host' => env('DB_HOST', '127.0.0.1'),
            'port' => env('DB_PORT', '3306'),
            'database' => env('DB_DATABASE', 'forge'),
            'username' => env('DB_USERNAME', 'forge'),
            'password' => env('DB_PASSWORD', ''),
            'charset' => 'utf8',
            'collation' => 'utf8_unicode_ci',
            'prefix' => '',
            'strict' => false,
            'engine' => null,
        ],
'mysqlOne' => [
            'driver' => 'mysql',
            'host' => env('DB_HOST_ONE', '127.0.0.1'),
            'port' => env('DB_PORT', '3306'),
            'database' => env('DB_DATABASE_ONE', 'forge'),
            'username' => env('DB_USERNAME_ONE', 'forge'),
            'password' => env('DB_PASSWORD_ONE', ''),
            'charset' => 'utf8',
            'collation' => 'utf8_unicode_ci',
            'prefix' => '',
            'strict' => false,
            'engine' => null,
        ],
];

Once you have this you can create two base model class for each connection and define the connection name in those models

//BaseModel.php
protected $connection = 'mysql';

//BaseModelOne.php
protected $connection = 'mysqlOne';

You can extend these models to create more models for tables in each DB.

How to generate Class Diagram (UML) on Android Studio (IntelliJ Idea)

Update 24.3.2016

I have found this guide from VP https://knowhow.visual-paradigm.com/technical-support/running-vp-in-android-studio/ created on September 8, 2015.

Good to know - it is possible to integrate VP into Android studio (in my case 1.5.1) now. Do not forget to backup your Android Studio settings (you can find them in Users%userName/.AndroidStudioX.X on Windows) ahead of installation.

I was trying to make it work, but created vp project did not contain any diagrams. Maybe someone else will have more luck.


I was using this manual http://www.visual-paradigm.com/support/documents/vpuserguide/2381/2385/66578_creatingauml.html to make Visual Paradigm working in Android studio, but action in 2. did not invoke dialogue in 3. So I Have asked Visual Paradigm support for help and they replied that Android Studio integration is not supported right now.

Reply from Visual paradigm reply from Apr 17 2015:

Thank you for your inquiry and I'm very sorry that at the moment we only support integrate with the standard IntelliJ IDEA, but not integrate with the Android Studio. We may consider to support it in our future release, and I'll keep you post once there any update on this topics. Feel free to contact me for any questions and wish you have a good day!

This post was deleted, so I will try to make it more clear.

As such I am considering previous answers as misleading and not useful. Therefore I thing that it is important for others to know that, before they lose their time trying to make it working.

How can I convert string to datetime with format specification in JavaScript?

Use new Date(dateString) if your string is compatible with Date.parse(). If your format is incompatible (I think it is), you have to parse the string yourself (should be easy with regular expressions) and create a new Date object with explicit values for year, month, date, hour, minute and second.

XPath - Difference between node() and text()

text() and node() are node tests, in XPath terminology (compare).

Node tests operate on a set (on an axis, to be exact) of nodes and return the ones that are of a certain type. When no axis is mentioned, the child axis is assumed by default.

There are all kinds of node tests:

  • node() matches any node (the least specific node test of them all)
  • text() matches text nodes only
  • comment() matches comment nodes
  • * matches any element node
  • foo matches any element node named "foo"
  • processing-instruction() matches PI nodes (they look like <?name value?>).
  • Side note: The * also matches attribute nodes, but only along the attribute axis. @* is a shorthand for attribute::*. Attributes are not part of the child axis, that's why a normal * does not select them.

This XML document:

<produce>
    <item>apple</item>
    <item>banana</item>
    <item>pepper</item>
</produce>

represents the following DOM (simplified):

root node
   element node (name="produce")
      text node (value="\n    ")
      element node (name="item")
         text node (value="apple")
      text node (value="\n    ")
      element node (name="item")
         text node (value="banana")
      text node (value="\n    ")
      element node (name="item")
         text node (value="pepper")
      text node (value="\n")

So with XPath:

  • / selects the root node
  • /produce selects a child element of the root node if it has the name "produce" (This is called the document element; it represents the document itself. Document element and root node are often confused, but they are not the same thing.)
  • /produce/node() selects any type of child node beneath /produce/ (i.e. all 7 children)
  • /produce/text() selects the 4 (!) whitespace-only text nodes
  • /produce/item[1] selects the first child element named "item"
  • /produce/item[1]/text() selects all child text nodes (there's only one - "apple" - in this case)

And so on.

So, your questions

  • "Select the text of all items under produce" /produce/item/text() (3 nodes selected)
  • "Select all the manager nodes in all departments" //department/manager (1 node selected)

Notes

  • The default axis in XPath is the child axis. You can change the axis by prefixing a different axis name. For example: //item/ancestor::produce
  • Element nodes have text values. When you evaluate an element node, its textual contents will be returned. In case of this example, /produce/item[1]/text() and string(/produce/item[1]) will be the same.
  • Also see this answer where I outline the individual parts of an XPath expression graphically.

Arduino Tools > Serial Port greyed out

The following steps install the IDE and remove the error java.lang.NullPointerException thrown while loading gnu.io.RXTXCommDriver which usually comes with arduino installed with apt-get command in Ubuntu.

Install the IDE

sudo apt-get install arduino

for removing java error in IDE

sudo add-apt-repository ppa:webupd8team/java
sudo apt update
sudo apt install oracle-java8-set-default

This also shows the Serial Port which was grayed out due to the error.

How to add Headers on RESTful call using Jersey Client API

Try this!

Client client = ClientBuilder.newClient();

String jsonStr = client
            .target("http:....")
            .request(MediaType.APPLICATION_JSON)

            .header("WM_SVC.NAME", "RegistryService")
            .header("WM_QOS.CORRELATION_ID", "d1f0c0d2-2cf4-497b-b630-06d609d987b0")

            .get(String.class);

P.S You can add any number of headers like this!

POI setting Cell Background to a Custom Color

You can set custom color using this-

check out this - click hear

XSSFWorkbook workbook = new XSSFWorkbook();

IndexedColorMap colorMap = workbook.getStylesSource().getIndexedColors();
Font tableHeadOneFontStyle = workbook.createFont();
        tableHeadOneFontStyle.setBold( true );
        tableHeadOneFontStyle.setColor( IndexedColors.BLACK.getIndex() );

XSSFCellStyle tableHeaderOneColOneStyle = workbook.createCellStyle();
        tableHeaderOneColOneStyle.setFont( tableHeadOneFontStyle );
        tableHeaderOneColOneStyle
                .setFillForegroundColor( new XSSFColor( new java.awt.Color( 255, 231, 153 ), colorMap ) );
        tableHeaderOneColOneStyle.setFillPattern( FillPatternType.SOLID_FOREGROUND );
        tableHeaderOneColOneStyle = setLeftRightBorderColor( tableHeaderOneColOneStyle );
        tableHeaderOneColOneStyle = alignCenter( tableHeaderOneColOneStyle );

Does reading an entire file leave the file handle open?

You can use pathlib.

For Python 3.5 and above:

from pathlib import Path
contents = Path(file_path).read_text()

For older versions of Python use pathlib2:

$ pip install pathlib2

Then:

from pathlib2 import Path
contents = Path(file_path).read_text()

This is the actual read_text implementation:

def read_text(self, encoding=None, errors=None):
    """
    Open the file in text mode, read it, and close the file.
    """
    with self.open(mode='r', encoding=encoding, errors=errors) as f:
        return f.read()

How can I tell AngularJS to "refresh"

Why $apply should be called?

TL;DR: $apply should be called whenever you want to apply changes made outside of Angular world.


Just to update @Dustin's answer, here is an explanation of what $apply exactly does and why it works.

$apply() is used to execute an expression in AngularJS from outside of the AngularJS framework. (For example from browser DOM events, setTimeout, XHR or third party libraries). Because we are calling into the AngularJS framework we need to perform proper scope life cycle of exception handling, executing watches.

Angular allows any value to be used as a binding target. Then at the end of any JavaScript code turn, it checks to see if the value has changed. That step that checks to see if any binding values have changed actually has a method, $scope.$digest()1. We almost never call it directly, as we use $scope.$apply() instead (which will call $scope.$digest).

Angular only monitors variables used in expressions and anything inside of a $watch living inside the scope. So if you are changing the model outside of the Angular context, you will need to call $scope.$apply() for those changes to be propagated, otherwise Angular will not know that they have been changed thus the binding will not be updated2.

Boolean checking in the 'if' condition

If you look at the alternatives on this page, of course the first option looks better and the second one is just more verbose. But if you are looking through a large class that someone else wrote, that verbosity can make the difference between realizing right away what the conditional is testing or not.

One of the reasons I moved away from Perl is because it relies so heavily on punctuation, which is much slower to interpret while reading.

I know I'm outvoted here, but I will almost always side with more explicit code so others can read it more accurately. Then again, I would never use a boolean variable called "status" either. Maybe isSuccess or just success, but "status" being true or false does not mean anything to the casual reader intuitively. As you can tell, I'm very into code readability because I read so much code others have written.

Using Excel OleDb to get sheet names IN SHEET ORDER

Can't find this in actual MSDN documentation, but a moderator in the forums said

I am afraid that OLEDB does not preserve the sheet order as they were in Excel

Excel Sheet Names in Sheet Order

Seems like this would be a common enough requirement that there would be a decent workaround.

How to enable loglevel debug on Apache2 server

Do note that on newer Apache versions the RewriteLog and RewriteLogLevel have been removed, and in fact will now trigger an error when trying to start Apache (at least on my XAMPP installation with Apache 2.4.2):

AH00526: Syntax error on line xx of path/to/config/file.conf: Invalid command 'RewriteLog', perhaps misspelled or defined by a module not included in the server configuration`

Instead, you're now supposed to use the general LogLevel directive, with a level of trace1 up to trace8. 'debug' didn't display any rewrite messages in the log for me.

Example: LogLevel warn rewrite:trace3

For the official documentation, see here.

Of course this also means that now your rewrite logs will be written in the general error log file and you'll have to sort them out yourself.

ng-change get new value and original value

Just keep a currentValue variable in your controller that you update on every change. You can then compare that to the new value every time before you update it.'

The idea of using a watch is good as well, but I think a simple variable is the simplest and most logical solution.

How to remove the underline for anchors(links)?

Sometime it will override by some rendering UI CSS. Better to use:

a.className {
    text-decoration: none !important;
}

Magento - How to add/remove links on my account navigation?

The easiest way to remove any link from the My Account panel in Magento is to first copy:

app/design/frontend/base/default/template/customer/account/navigation.phtml

to

app/design/frontend/enterprise/YOURSITE/template/customer/account/navigation.phtml

Open the file and fine this line, it should be around line 34:

<?php $_index = 1; ?>

Right below it add this:

 <?php $_count = count($_links); /* Add or Remove Account Left Navigation Links Here -*/
        unset($_links['tags']); /* My Tags */
        unset($_links['invitations']); /* My Invitations */
        unset($_links['enterprise_customerbalance']); /* Store Credit */
        unset($_links['OAuth Customer Tokens']); /* My Applications */
        unset($_links['enterprise_reward']); /* Reward Points */
        unset($_links['giftregistry']); /* Gift Registry */
        unset($_links['downloadable_products']); /* My Downloadable Products */
        unset($_links['recurring_profiles']); /* Recurring Profiles */
        unset($_links['billing_agreements']); /* Billing Agreements */
        unset($_links['enterprise_giftcardaccount']); /* Gift Card Link */
        ?> 

Just remove any of the links here that you DO want to appear.

How Big can a Python List Get?

I got this from here on a x64 bit system: Python 3.7.0b5 (v3.7.0b5:abb8802389, May 31 2018, 01:54:01) [MSC v.1913 64 bit (AMD64)] on win32

enter image description here

What is this CSS selector? [class*="span"]

The Following:

.show-grid [class*="span"] {

means that all child elements of '.show-grid' with a class that CONTAINS the word 'span' in it will acquire those CSS properties.

<div class="show-grid">
  <div class="span">.span</div>
  <div class="span6">span6</div>
  <div class="attention-span">attention</div>
  <div class="spanish">spanish</div>
  <div class="mariospan">mariospan</div>
  <div class="espanol">espanol</div>

  <div>
    <div class="span">.span</div>
  </div>

  <p class="span">span</p>
  <span class="span">I do GET HIT</span>

  <span>I DO NOT GET HIT since I need a class of 'span'</span>
</div>

<div class="span">I DO NOT GET HIT since I'm outside of .show-grid</span>

All of the elements get hit except for the <span> by itself.


In Regards to Bootstrap:

  • span6 : this was Bootstrap 2's scaffolding technique which divided a section into a horizontal grid, based on parts of 12. Thus span6 would have a width of 50%.
  • In the current day implementation of Bootstrap (v.3 and v.4), you now use the .col-* classes (e.g. col-sm-6), which also specifies a media breakpoint to handle responsiveness when the window shrinks below a certain size. Check Bootstrap 4.1 and Bootstrap 3.3.7 for more documentation. I would recommend going with a later Bootstrap nowadays

What is the difference between join and merge in Pandas?

pandas.merge() is the underlying function used for all merge/join behavior.

DataFrames provide the pandas.DataFrame.merge() and pandas.DataFrame.join() methods as a convenient way to access the capabilities of pandas.merge(). For example, df1.merge(right=df2, ...) is equivalent to pandas.merge(left=df1, right=df2, ...).

These are the main differences between df.join() and df.merge():

  1. lookup on right table: df1.join(df2) always joins via the index of df2, but df1.merge(df2) can join to one or more columns of df2 (default) or to the index of df2 (with right_index=True).
  2. lookup on left table: by default, df1.join(df2) uses the index of df1 and df1.merge(df2) uses column(s) of df1. That can be overridden by specifying df1.join(df2, on=key_or_keys) or df1.merge(df2, left_index=True).
  3. left vs inner join: df1.join(df2) does a left join by default (keeps all rows of df1), but df.merge does an inner join by default (returns only matching rows of df1 and df2).

So, the generic approach is to use pandas.merge(df1, df2) or df1.merge(df2). But for a number of common situations (keeping all rows of df1 and joining to an index in df2), you can save some typing by using df1.join(df2) instead.

Some notes on these issues from the documentation at http://pandas.pydata.org/pandas-docs/stable/merging.html#database-style-dataframe-joining-merging:

merge is a function in the pandas namespace, and it is also available as a DataFrame instance method, with the calling DataFrame being implicitly considered the left object in the join.

The related DataFrame.join method, uses merge internally for the index-on-index and index-on-column(s) joins, but joins on indexes by default rather than trying to join on common columns (the default behavior for merge). If you are joining on index, you may wish to use DataFrame.join to save yourself some typing.

...

These two function calls are completely equivalent:

left.join(right, on=key_or_keys)
pd.merge(left, right, left_on=key_or_keys, right_index=True, how='left', sort=False)

PL/SQL block problem: No data found error

There is an alternative approach I used when I couldn't rely on the EXCEPTION block at the bottom of my procedure. I had variables declared at the beginning:

my_value VARCHAR := 'default';
number_rows NUMBER := 0;
.
.
.
SELECT count(*) FROM TABLE INTO number_rows (etc.)

IF number_rows > 0 -- Then obtain my_value with a query or constant, etc.
END IF;

How to get status code from webclient?

Tried it out. ResponseHeaders do not include status code.

If I'm not mistaken, WebClient is capable of abstracting away multiple distinct requests in a single method call (e.g. correctly handling 100 Continue responses, redirects, and the like). I suspect that without using HttpWebRequest and HttpWebResponse, a distinct status code may not be available.

It occurs to me that, if you are not interested in intermediate status codes, you can safely assume the final status code is in the 2xx (successful) range, otherwise, the call would not be successful.

The status code unfortunately isn't present in the ResponseHeaders dictionary.

Java Keytool error after importing certificate , "keytool error: java.io.FileNotFoundException & Access Denied"

This could happen if you are not running the command prompt in administrator mode. If you are using windows 7, you can go to run, type cmd and hit Ctrl+Shift+enter. This will open the command prompt in administrator mode. If not, you can also go to start -> all programs -> accessories -> right click command prompt and click 'run as administrator'.

How to close Android application?

Android has a mechanism in place to close an application safely per its documentation. In the last Activity that is exited (usually the main Activity that first came up when the application started) just place a couple of lines in the onDestroy() method. The call to System.runFinalizersOnExit(true) ensures that all objects will be finalized and garbage collected when the the application exits. You can also kill an application quickly via android.os.Process.killProcess(android.os.Process.myPid()) if you prefer. The best way to do this is put a method like the following in a helper class and then call it whenever the app needs to be killed. For example in the destroy method of the root activity (assuming that the app never kills this activity):

Also Android will not notify an application of the HOME key event, so you cannot close the application when the HOME key is pressed. Android reserves the HOME key event to itself so that a developer cannot prevent users from leaving their application. However you can determine with the HOME key is pressed by setting a flag to true in a helper class that assumes that the HOME key has been pressed, then changing the flag to false when an event occurs that shows the HOME key was not pressed and then checking to see of the HOME key pressed in the onStop() method of the activity.

Don't forget to handle the HOME key for any menus and in the activities that are started by the menus. The same goes for the SEARCH key. Below is some example classes to illustrate:

Here's an example of a root activity that kills the application when it is destroyed:

package android.example;

/**
 * @author Danny Remington - MacroSolve
 */

public class HomeKey extends CustomActivity {

    public void onDestroy() {
        super.onDestroy();

        /*
         * Kill application when the root activity is killed.
         */
        UIHelper.killApp(true);
    }

}

Here's an abstract activity that can be extended to handle the HOME key for all activities that extend it:

package android.example;

/**
 * @author Danny Remington - MacroSolve
 */

import android.app.Activity;
import android.view.Menu;
import android.view.MenuInflater;

/**
 * Activity that includes custom behavior shared across the application. For
 * example, bringing up a menu with the settings icon when the menu button is
 * pressed by the user and then starting the settings activity when the user
 * clicks on the settings icon.
 */
public abstract class CustomActivity extends Activity {
    public void onStart() {
        super.onStart();

        /*
         * Check if the app was just launched. If the app was just launched then
         * assume that the HOME key will be pressed next unless a navigation
         * event by the user or the app occurs. Otherwise the user or the app
         * navigated to this activity so the HOME key was not pressed.
         */

        UIHelper.checkJustLaunced();
    }

    public void finish() {
        /*
         * This can only invoked by the user or the app finishing the activity
         * by navigating from the activity so the HOME key was not pressed.
         */
        UIHelper.homeKeyPressed = false;
        super.finish();
    }

    public void onStop() {
        super.onStop();

        /*
         * Check if the HOME key was pressed. If the HOME key was pressed then
         * the app will be killed. Otherwise the user or the app is navigating
         * away from this activity so assume that the HOME key will be pressed
         * next unless a navigation event by the user or the app occurs.
         */
        UIHelper.checkHomeKeyPressed(true);
    }

    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.settings_menu, menu);

        /*
         * Assume that the HOME key will be pressed next unless a navigation
         * event by the user or the app occurs.
         */
        UIHelper.homeKeyPressed = true;

        return true;
    }

    public boolean onSearchRequested() {
        /*
         * Disable the SEARCH key.
         */
        return false;
    }
}

Here's an example of a menu screen that handles the HOME key:

/**
 * @author Danny Remington - MacroSolve
 */

package android.example;

import android.os.Bundle;
import android.preference.PreferenceActivity;

/**
 * PreferenceActivity for the settings screen.
 * 
 * @see PreferenceActivity
 * 
 */
public class SettingsScreen extends PreferenceActivity {
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.layout.settings_screen);
    }

    public void onStart() {
        super.onStart();

        /*
         * This can only invoked by the user or the app starting the activity by
         * navigating to the activity so the HOME key was not pressed.
         */
        UIHelper.homeKeyPressed = false;
    }

    public void finish() {
        /*
         * This can only invoked by the user or the app finishing the activity
         * by navigating from the activity so the HOME key was not pressed.
         */
        UIHelper.homeKeyPressed = false;
        super.finish();
    }

    public void onStop() {
        super.onStop();

        /*
         * Check if the HOME key was pressed. If the HOME key was pressed then
         * the app will be killed either safely or quickly. Otherwise the user
         * or the app is navigating away from the activity so assume that the
         * HOME key will be pressed next unless a navigation event by the user
         * or the app occurs.
         */
        UIHelper.checkHomeKeyPressed(true);
    }

    public boolean onSearchRequested() {
        /*
         * Disable the SEARCH key.
         */
        return false;
    }

}

Here's an example of a helper class that handles the HOME key across the app:

package android.example;

/**
 * @author Danny Remington - MacroSolve
 *
 */

/**
 * Helper class to help handling of UI.
 */
public class UIHelper {
    public static boolean homeKeyPressed;
    private static boolean justLaunched = true;

    /**
     * Check if the app was just launched. If the app was just launched then
     * assume that the HOME key will be pressed next unless a navigation event
     * by the user or the app occurs. Otherwise the user or the app navigated to
     * the activity so the HOME key was not pressed.
     */
    public static void checkJustLaunced() {
        if (justLaunched) {
            homeKeyPressed = true;
            justLaunched = false;
        } else {
            homeKeyPressed = false;
        }
    }

    /**
     * Check if the HOME key was pressed. If the HOME key was pressed then the
     * app will be killed either safely or quickly. Otherwise the user or the
     * app is navigating away from the activity so assume that the HOME key will
     * be pressed next unless a navigation event by the user or the app occurs.
     * 
     * @param killSafely
     *            Primitive boolean which indicates whether the app should be
     *            killed safely or quickly when the HOME key is pressed.
     * 
     * @see {@link UIHelper.killApp}
     */
    public static void checkHomeKeyPressed(boolean killSafely) {
        if (homeKeyPressed) {
            killApp(true);
        } else {
            homeKeyPressed = true;
        }
    }

    /**
     * Kill the app either safely or quickly. The app is killed safely by
     * killing the virtual machine that the app runs in after finalizing all
     * {@link Object}s created by the app. The app is killed quickly by abruptly
     * killing the process that the virtual machine that runs the app runs in
     * without finalizing all {@link Object}s created by the app. Whether the
     * app is killed safely or quickly the app will be completely created as a
     * new app in a new virtual machine running in a new process if the user
     * starts the app again.
     * 
     * <P>
     * <B>NOTE:</B> The app will not be killed until all of its threads have
     * closed if it is killed safely.
     * </P>
     * 
     * <P>
     * <B>NOTE:</B> All threads running under the process will be abruptly
     * killed when the app is killed quickly. This can lead to various issues
     * related to threading. For example, if one of those threads was making
     * multiple related changes to the database, then it may have committed some
     * of those changes but not all of those changes when it was abruptly
     * killed.
     * </P>
     * 
     * @param killSafely
     *            Primitive boolean which indicates whether the app should be
     *            killed safely or quickly. If true then the app will be killed
     *            safely. Otherwise it will be killed quickly.
     */
    public static void killApp(boolean killSafely) {
        if (killSafely) {
            /*
             * Notify the system to finalize and collect all objects of the app
             * on exit so that the virtual machine running the app can be killed
             * by the system without causing issues. NOTE: If this is set to
             * true then the virtual machine will not be killed until all of its
             * threads have closed.
             */
            System.runFinalizersOnExit(true);

            /*
             * Force the system to close the app down completely instead of
             * retaining it in the background. The virtual machine that runs the
             * app will be killed. The app will be completely created as a new
             * app in a new virtual machine running in a new process if the user
             * starts the app again.
             */
            System.exit(0);
        } else {
            /*
             * Alternatively the process that runs the virtual machine could be
             * abruptly killed. This is the quickest way to remove the app from
             * the device but it could cause problems since resources will not
             * be finalized first. For example, all threads running under the
             * process will be abruptly killed when the process is abruptly
             * killed. If one of those threads was making multiple related
             * changes to the database, then it may have committed some of those
             * changes but not all of those changes when it was abruptly killed.
             */
            android.os.Process.killProcess(android.os.Process.myPid());
        }

    }
}

Method to find string inside of the text file. Then getting the following lines up to a certain limit

You can do something like this:

File file = new File("Student.txt");

try {
    Scanner scanner = new Scanner(file);

    //now read the file line by line...
    int lineNum = 0;
    while (scanner.hasNextLine()) {
        String line = scanner.nextLine();
        lineNum++;
        if(<some condition is met for the line>) { 
            System.out.println("ho hum, i found it on line " +lineNum);
        }
    }
} catch(FileNotFoundException e) { 
    //handle this
}

How can I get the number of records affected by a stored procedure?

@@RowCount will give you the number of records affected by a SQL Statement.

The @@RowCount works only if you issue it immediately afterwards. So if you are trapping errors, you have to do it on the same line. If you split it up, you will miss out on whichever one you put second.

SELECT @NumRowsChanged = @@ROWCOUNT, @ErrorCode = @@ERROR

If you have multiple statements, you will have to capture the number of rows affected for each one and add them up.

SELECT @NumRowsChanged = @NumRowsChanged  + @@ROWCOUNT, @ErrorCode = @@ERROR

How to find if element with specific id exists or not

Use typeof for elements checks.

if(typeof(element) === 'undefined')
{
// then field does not exist
}

Call jQuery Ajax Request Each X Minutes

you can use setInterval() in javascript

<script>
//Call the yourAjaxCall() function every 1000 millisecond
setInterval("yourAjaxCall()",1000);
function yourAjaxCall(){...}
</script>

How to set up devices for VS Code for a Flutter emulator

Alternatively if you enable developer mode and (ADB) is still needed you can use connect to the device.

To enable developer Mode you go to Phone Settings > About Phone > tap buildnumber 7 times

once you have it enabled and have the device connected you can start seeing the device in VSCode

How can I match on an attribute that contains a certain string?

A 2.0 XPath that works:

//*[tokenize(@class,'\s+')='atag']

or with a variable:

//*[tokenize(@class,'\s+')=$classname]

List only stopped Docker containers

The typical command is:

docker container ls -f 'status=exited'

However, this will only list one of the possible non-running statuses. Here's a list of all possible statuses:

  • created
  • restarting
  • running
  • removing
  • paused
  • exited
  • dead

You can filter on multiple statuses by passing multiple filters on the status:

docker container ls -f 'status=exited' -f 'status=dead' -f 'status=created'

If you are integrating this with an automatic cleanup script, you can chain one command to another with some bash syntax, output just the container id's with -q, and you can also limit to just the containers that exited successfully with an exit code filter:

docker container rm $(docker container ls -q -f 'status=exited' -f 'exited=0')

For more details on filters you can use, see Docker's documentation: https://docs.docker.com/engine/reference/commandline/ps/#filtering

How do you format a Date/Time in TypeScript?

function _formatDatetime(date: Date, format: string) {
   const _padStart = (value: number): string => value.toString().padStart(2, '0');
return format
    .replace(/yyyy/g, _padStart(date.getFullYear()))
    .replace(/dd/g, _padStart(date.getDate()))
    .replace(/mm/g, _padStart(date.getMonth() + 1))
    .replace(/hh/g, _padStart(date.getHours()))
    .replace(/ii/g, _padStart(date.getMinutes()))
    .replace(/ss/g, _padStart(date.getSeconds()));
}
function isValidDate(d: Date): boolean {
    return !isNaN(d.getTime());
}
export function formatDate(date: any): string {
    var datetime = new Date(date);
    return isValidDate(datetime) ? _formatDatetime(datetime, 'yyyy-mm-dd hh:ii:ss') : '';
}

"call to undefined function" error when calling class method

Another silly mistake you can do is copy recursive function from non class environment to class and don`t change inner self calls to $this->method_name()

i`m writing this because couldn`t understand why i got this error and this thread is first in google when you search for this error.

CAST to DECIMAL in MySQL

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

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

You can try it here:

warning about too many open figures

The following snippet solved the issue for me:


class FigureWrapper(object):
    '''Frees underlying figure when it goes out of scope. 
    '''

    def __init__(self, figure):
        self._figure = figure

    def __del__(self):
        plt.close(self._figure)
        print("Figure removed")


# .....
    f, ax = plt.subplots(1, figsize=(20, 20))
    _wrapped_figure = FigureWrapper(f)

    ax.plot(...
    plt.savefig(...
# .....

When _wrapped_figure goes out of scope the runtime calls our __del__() method with plt.close() inside. It happens even if exception fires after _wrapped_figure constructor.

RuntimeWarning: DateTimeField received a naive datetime

make sure settings.py has USE_TZ = True

In your python file:

from django.utils import timezone

timezone.now() # use its value in model field

How Can I Resolve:"can not open 'git-upload-pack' " error in eclipse?

This works for me: http://gitblit.com/setup_client.html

Eclipse/EGit/JGit

Window->Preferences->Team->Git->Configuration
Click the New Entry button

Key = http.sslVerify
Value = false

Load resources from relative path using local html in uiwebview

In Swift 3.01 using WKWebView:

let localURL = URL.init(fileURLWithPath: Bundle.main.path(forResource: "index", ofType: "html", inDirectory: "CWP")!)
myWebView.load(NSURLRequest.init(url: localURL) as URLRequest)

This adjusts for some of the finer syntax changes in 3.01 and keeps the directory structure in place so you can embed related HTML files.

Create a function with optional call variables

Powershell provides a lot of built-in support for common parameter scenarios, including mandatory parameters, optional parameters, "switch" (aka flag) parameters, and "parameter sets."

By default, all parameters are optional. The most basic approach is to simply check each one for $null, then implement whatever logic you want from there. This is basically what you have already shown in your sample code.

If you want to learn about all of the special support that Powershell can give you, check out these links:

about_Functions

about_Functions_Advanced

about_Functions_Advanced_Parameters

Checking if sys.argv[x] is defined

I use this - it never fails:

startingpoint = 'blah'
if sys.argv[1:]:
   startingpoint = sys.argv[1]

How do I use DateTime.TryParse with a Nullable<DateTime>?

This is the one liner you're looking fo:

DateTime? d = DateTime.TryParse("some date text", out DateTime dt) ? dt : null;

If you want to make it a proper TryParse pseudo-extension method, you can do this:

public static bool TryParse(string text, out DateTime? dt)
{
    if (DateTime.TryParse(text, out DateTime date))
    {
        dt = date;
        return true;
    }
    else
    {
        dt = null;
        return false;
    }
}

download a file from Spring boot rest service

I would suggest using a StreamingResponseBody since with it the application can write directly to the response (OutputStream) without holding up the Servlet container thread. It is a good approach if you are downloading a file very large.

@GetMapping("download")
public StreamingResponseBody downloadFile(HttpServletResponse response, @PathVariable Long fileId) {

    FileInfo fileInfo = fileService.findFileInfo(fileId);
    response.setContentType(fileInfo.getContentType());
    response.setHeader(
        HttpHeaders.CONTENT_DISPOSITION, "attachment;filename=\"" + fileInfo.getFilename() + "\"");

    return outputStream -> {
        int bytesRead;
        byte[] buffer = new byte[BUFFER_SIZE];
        InputStream inputStream = fileInfo.getInputStream();
        while ((bytesRead = inputStream.read(buffer)) != -1) {
            outputStream.write(buffer, 0, bytesRead);
        }
    };
}

Ps.: When using StreamingResponseBody, it is highly recommended to configure TaskExecutor used in Spring MVC for executing asynchronous requests. TaskExecutor is an interface that abstracts the execution of a Runnable.

More info: https://medium.com/swlh/streaming-data-with-spring-boot-restful-web-service-87522511c071

Understanding the Gemfile.lock file

It looks to me like PATH lists the first-generation dependencies directly from your gemspec, whereas GEM lists second-generation dependencies (i.e. what your dependencies depend on) and those from your Gemfile. PATH::remote is . because it relied on a local gemspec in the current directory to find out what belongs in PATH::spec, whereas GEM::remote is rubygems.org, since that's where it had to go to find out what belongs in GEM::spec.

In a Rails plugin, you'll see a PATH section, but not in a Rails app. Since the app doesn't have a gemspec file, there would be nothing to put in PATH.

As for DEPENDENCIES, gembundler.com states:

Runtime dependencies in your gemspec are treated like base dependencies, 
and development dependencies are added by default to the group, :development

The Gemfile generated by rails plugin new my_plugin says something similar:

# Bundler will treat runtime dependencies like base dependencies, and
# development dependencies will be added by default to the :development group.

What this means is that the difference between

s.add_development_dependency "july" # (1)

and

s.add_dependency "july" # (2)

is that (1) will only include "july" in Gemfile.lock (and therefore in the application) in a development environment. So when you run bundle install, you'll see "july" not only under PATH but also under DEPENDENCIES, but only in development. In production, it won't be there at all. However, when you use (2), you'll see "july" only in PATH, not in DEPENDENCIES, but it will show up when you bundle install from a production environment (i.e. in some other gem that includes yours as a dependency), not only development.

These are just my observations and I can't fully explain why any of this is the way it is but I welcome further comments.

How to update values in a specific row in a Python Pandas DataFrame?

So first of all, pandas updates using the index. When an update command does not update anything, check both left-hand side and right-hand side. If you don't update the indices to follow your identification logic, you can do something along the lines of

>>> df.loc[df.filename == 'test2.dat', 'n'] = df2[df2.filename == 'test2.dat'].loc[0]['n']
>>> df
Out[331]: 
    filename   m     n
0  test0.dat  12  None
1  test2.dat  13    16

If you want to do this for the whole table, I suggest a method I believe is superior to the previously mentioned ones: since your identifier is filename, set filename as your index, and then use update() as you wanted to. Both merge and the apply() approach contain unnecessary overhead:

>>> df.set_index('filename', inplace=True)
>>> df2.set_index('filename', inplace=True)
>>> df.update(df2)
>>> df
Out[292]: 
            m     n
filename           
test0.dat  12  None
test2.dat  13    16

"While .. End While" doesn't work in VBA?

While constructs are terminated not with an End While but with a Wend.

While counter < 20
    counter = counter + 1
Wend

Note that this information is readily available in the documentation; just press F1. The page you link to deals with Visual Basic .NET, not VBA. While (no pun intended) there is some degree of overlap in syntax between VBA and VB.NET, one can't just assume that the documentation for the one can be applied directly to the other.

Also in the VBA help file:

Tip The Do...Loop statement provides a more structured and flexible way to perform looping.

Get absolute path to workspace directory in Jenkins Pipeline plugin

For me WORKSPACE was a valid property of the pipeline itself. So when I handed over this to a Groovy method as parameter context from the pipeline script itself, I was able to access the correct value using "... ${context.WORKSPACE} ..."

(on Jenkins 2.222.3, Build Pipeline Plugin 1.5.8, Pipeline: Nodes and Processes 2.35)

Read/write files within a Linux kernel module

Since version 4.14 of Linux kernel, vfs_read and vfs_write functions are no longer exported for use in modules. Instead, functions exclusively for kernel's file access are provided:

# Read the file from the kernel space.
ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos);

# Write the file from the kernel space.
ssize_t kernel_write(struct file *file, const void *buf, size_t count,
            loff_t *pos);

Also, filp_open no longer accepts user-space string, so it can be used for kernel access directly (without dance with set_fs).

find without recursion

I believe you are looking for -maxdepth 1.

What is the difference between ng-if and ng-show/ng-hide

  1. ng-if if false will remove elements from DOM. This means that all your events, directives attached to those elements will be lost. For example, ng-click to one of child elements, when ng-if evaluates to false, that element will be removed from DOM and again when it is true it is recreated.

  2. ng-show/ng-hide does not remove the elements from DOM. It uses CSS styles (.ng-hide) to hide/show elements .This way your events, directives that were attached to children will not be lost.

  3. ng-if creates a child scope while ng-show/ng-hide does not.

Java 8 lambdas, Function.identity() or t->t

As of the current JRE implementation, Function.identity() will always return the same instance while each occurrence of identifier -> identifier will not only create its own instance but even have a distinct implementation class. For more details, see here.

The reason is that the compiler generates a synthetic method holding the trivial body of that lambda expression (in the case of x->x, equivalent to return identifier;) and tell the runtime to create an implementation of the functional interface calling this method. So the runtime sees only different target methods and the current implementation does not analyze the methods to find out whether certain methods are equivalent.

So using Function.identity() instead of x -> x might save some memory but that shouldn’t drive your decision if you really think that x -> x is more readable than Function.identity().

You may also consider that when compiling with debug information enabled, the synthetic method will have a line debug attribute pointing to the source code line(s) holding the lambda expression, therefore you have a chance of finding the source of a particular Function instance while debugging. In contrast, when encountering the instance returned by Function.identity() during debugging an operation, you won’t know who has called that method and passed the instance to the operation.

Add column in dataframe from list

Just assign the list directly:

df['new_col'] = mylist

Alternative
Convert the list to a series or array and then assign:

se = pd.Series(mylist)
df['new_col'] = se.values

or

df['new_col'] = np.array(mylist)

Qt Creator color scheme

Simple in two line

  1. Go to "Tools" -> "Options" -> "Environment" -> "General" tab,
  2. Change "Theme" to dark

How can I make SQL case sensitive string comparison on MySQL?

mysql is not case sensitive by default, try changing the language collation to latin1_general_cs

How to change Format of a Cell to Text using VBA

for large numbers that display with scientific notation set format to just '#'

Android Emulator Error Message: "PANIC: Missing emulator engine program for 'x86' CPUS."

This worked for me on macOS:

echo 'export PATH=$PATH:'$HOME'/Library/Android/sdk/emulator:'$HOME'/Library/Android/sdk/tools:'$HOME'/Library/Android/sdk/platform-tools' >> ~/.bash_profile
source ~/.bash_profile

Convert INT to VARCHAR SQL

SELECT cast(CAST([field_name] AS bigint) as nvarchar(255)) FROM table_name

Netbeans installation doesn't find JDK

Set the JAVA_HOME variable as noted above, but also set the JRE_HOME variable to the Java Runtime Environment folder (example: C:\Program Files (x86)\Java\jdk1.6.0_23\jre )

To set the windows environment variable, right click on My Computer and select "Properties" and choose the "Advanced" tab on older windows versions, or click the "Advanced system settings" link on new versions of windows. Click the "Environment Variables" button and, in the System Variables section, click the "New" button and add the above variable names and enter the appropriate filesystem paths as the values.

After you've installed Netbeans, check the following:

Open C:\Program Files (x86)\NetBeans 6.0.1\etc\netbeans.conf

Change this value to the location of your JDK folder if it isn't set correctly already:

netbeans_jdkhome="C:\Program Files (x86)\Java\jdk1.6.0_23"

How do I print bold text in Python?

Simple Boldness - Two Line Code

In python 3 you could use colorama - simple_colors: (Simple Colours page: https://pypi.org/project/simple-colors/ - go to the heading 'Usage'.) Before you do what is below, make sure you pip install simple_colours.

from simple_colors import *
print(green('hello', 'bold'))

enter image description here

What is the difference between connection and read timeout for sockets?

These are timeout values enforced by JVM for TCP connection establishment and waiting on reading data from socket.

If the value is set to infinity, you will not wait forever. It simply means JVM doesn't have timeout and OS will be responsible for all the timeouts. However, the timeouts on OS may be really long. On some slow network, I've seen timeouts as long as 6 minutes.

Even if you set the timeout value for socket, it may not work if the timeout happens in the native code. We can reproduce the problem on Linux by connecting to a host blocked by firewall or unplugging the cable on switch.

The only safe approach to handle TCP timeout is to run the connection code in a different thread and interrupt the thread when it takes too long.

Get Row Index on Asp.net Rowcommand event

this is answer for your question.

GridViewRow gvr = (GridViewRow)((ImageButton)e.CommandSource).NamingContainer;

int RowIndex = gvr.RowIndex; 

Parse (split) a string in C++ using string delimiter (standard C++)

I would use boost::tokenizer. Here's documentation explaining how to make an appropriate tokenizer function: http://www.boost.org/doc/libs/1_52_0/libs/tokenizer/tokenizerfunction.htm

Here's one that works for your case.

struct my_tokenizer_func
{
    template<typename It>
    bool operator()(It& next, It end, std::string & tok)
    {
        if (next == end)
            return false;
        char const * del = ">=";
        auto pos = std::search(next, end, del, del + 2);
        tok.assign(next, pos);
        next = pos;
        if (next != end)
            std::advance(next, 2);
        return true;
    }

    void reset() {}
};

int main()
{
    std::string to_be_parsed = "1) one>=2) two>=3) three>=4) four";
    for (auto i : boost::tokenizer<my_tokenizer_func>(to_be_parsed))
        std::cout << i << '\n';
}

Best way to add Activity to an Android project in Eclipse?

I just use the "New Class" dialog in Eclipse and set the base class as Activity. I'm not aware of any other way to do this. What other method would you expect to be available?

HTML.ActionLink method

Html.ActionLink(article.Title, "Login/" + article.ArticleID, 'Item") 

Is "&#160;" a replacement of "&nbsp;"?

  • &nbsp; is the character entity reference (meant to be easily parseable by humans).
  • &#160; is the numeric entity reference (meant to be easily parseable by machines).

They are the same except for the fact that the latter does not need another lookup table to find its actual value. The lookup table is called a DTD, by the way.

You can read more about character entity references in the offical W3C documents.

How to both read and write a file in C#

This thread seems to answer your question : simultaneous-read-write-a-file

Basically, what you need is to declare two FileStream, one for read operations, the other for write operations. Writer Filestream needs to open your file in 'Append' mode.

Connect to external server by using phpMyAdmin

at version 4.0 or above, we need to create one 'config.inc.php' or rename the 'config.sample.inc.php' to 'config.inc.php';

In my case, I also work with one mysql server for each environment (dev and production):

/* others code*/  
$whoIam = gethostname();
switch($whoIam) {
    case 'devHost':
        $cfg['Servers'][$i]['host'] = 'localhost';
        break;
    case 'MasterServer':
        $cfg['Servers'][$i]['host'] = 'masterMysqlServer';
        break;
} /* others code*/ 

How to get streaming url from online streaming radio station

When you go to a stream url, you get offered a file. feed this file to a parser to extract the contents out of it. the file is (usually) plain text and contains the url to play.

How to search if dictionary value contains certain string with Python

Klaus solution has less overhead, on the other hand this one may be more readable

myDict = {'age': ['12'], 'address': ['34 Main Street, 212 First Avenue'],
          'firstName': ['Alan', 'Mary-Ann'], 'lastName': ['Stone', 'Lee']}

def search(myDict, lookup):
    for key, value in myDict.items():
        for v in value:
            if lookup in v:
                return key

search(myDict, 'Mary')

Spring JUnit: How to Mock autowired component in autowired component

Spring Boot 1.4 introduced testing annotation called @MockBean. So now mocking and spying on Spring beans is natively supported by Spring Boot.

C#: Waiting for all threads to complete

I was tying to figure out how to do this but i could not get any answers from google. I know this is an old thread but here was my solution:

Use the following class:

class ThreadWaiter
    {
        private int _numThreads = 0;
        private int _spinTime;

        public ThreadWaiter(int SpinTime)
        {
            this._spinTime = SpinTime;
        }

        public void AddThreads(int numThreads)
        {
            _numThreads += numThreads;
        }

        public void RemoveThread()
        {
            if (_numThreads > 0)
            {
                _numThreads--;
            }
        }

        public void Wait()
        {
            while (_numThreads != 0)
            {
                System.Threading.Thread.Sleep(_spinTime);
            }
        }
    }
  1. Call Addthreads(int numThreads) before executing a thread(s).
  2. Call RemoveThread() after each one has completed.
  3. Use Wait() at the point that you want to wait for all the threads to complete before continuing

Get absolute path of initially run script

A simple way to have the absolute path of the initially executed script, in that script and any other script included with include, require, require_once is by using a constant and storing there the current script path at beginning of the main script:

define( 'SCRIPT_ROOT', __FILE__ );

The solution above is suitable when there is a single "main" script that includes every other needed script, as in most web applications.

If that's not the case and there may be several "intital scripts" then to avoid redefinitions and to have the correct path stored inside the constant each script may begin with:

if( ! defined( 'SCRIPT_ROOT' ) ) {
    define( 'SCRIPT_ROOT`, __FILE__ );
}

A note about the (currently) accepted answer:

the answer states that the initially executed script path is the first element of the array returned by get_included_files().

This is a clever and simple solution and -at the time of writing- (we're almost at PHP 7.4.0) it does work.

However by looking at the documentation there is no mention that the initially executed script is the first item of the array returned by get_included_files().

We only read

The script originally called is considered an "included file," so it will be listed together with the files referenced by include and family.

At the time of writing the "script originally called" is the first one in the array but -technically- there is no guarantee that this won't change in the future.


A note about realpath(), __FILE__, and __DIR__:

Others have suggested in their answers the use of __FILE__, __DIR__, dirname(__FILE__), realpath(__DIR__)...

dirname(__FILE__) is equal to __DIR__ (introduced in PHP 5.3.0), so just use __DIR__.

Both __FILE__ and __DIR__ are always absolute paths so realpath() is unnecessary.

How to convert C++ Code to C

A compiler consists of two major blocks: the 'front end' and the 'back end'. The front end of a compiler analyzes the source code and builds some form of a 'intermediary representation' of said source code which is much easier to analyze by a machine algorithm than is the source code (i.e. whereas the source code e.g. C++ is designed to help the human programmer to write code, the intermediary form is designed to help simplify the algorithm that analyzes said intermediary form easier). The back end of a compiler takes the intermediary form and then converts it to a 'target language'.

Now, the target language for general-use compilers are assembler languages for various processors, but there's nothing to prohibit a compiler back end to produce code in some other language, for as long as said target language is (at least) as flexible as a general CPU assembler.

Now, as you can probably imagine, C is definitely as flexible as a CPU's assembler, such that a C++ to C compiler is really no problem to implement from a technical pov.

So you have: C++ ---frontEnd---> someIntermediaryForm ---backEnd---> C

You may want to check these guys out: http://www.edg.com/index.php?location=c_frontend (the above link is just informative for what can be done, they license their front ends for tens of thousands of dollars)

PS As far as i know, there is no such a C++ to C compiler by GNU, and this totally beats me (if i'm right about this). Because the C language is fairly small and it's internal mechanisms are fairly rudimentary, a C compiler requires something like one man-year work (i can tell you this first hand cause i wrote such a compiler myself may years ago, and it produces a [virtual] stack machine intermediary code), and being able to have a maintained, up-to-date C++ compiler while only having to write a C compiler once would be a great thing to have...

How to change UIPickerView height

It seems obvious that Apple doesn't particularly invite mucking with the default height of the UIPickerView, but I have found that you can achieve a change in the height of the view by taking complete control and passing a desired frame size at creation time, e.g:

smallerPicker = [[UIPickerView alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 120.0)];

You will discover that at various heights and widths, there are visual glitches. Obviously, these glitches would either need to be worked around somehow, or choose another size that doesn't exhibit them.

How does one add keyboard languages and switch between them in Linux Mint 16?

Go to menu , search for Regional Settings. Switch to Keyboard layouts tab. Click Options button. Search for Key(s) to change layout. There isn't a default one so you have to tick the combination you like. Enjoy.

ObservableCollection Doesn't support AddRange method, so I get notified for each item added, besides what about INotifyCollectionChanging?

As there might be a number of operations to do on an ObservableCollection for example Clear first then AddRange and then insert "All" item for a ComboBox I ended up with folowing solution:

public static class LinqExtensions
{
    public static ICollection<T> AddRange<T>(this ICollection<T> source, IEnumerable<T> addSource)
    {
        foreach(T item in addSource)
        {
            source.Add(item);
        }

        return source;
    }
}

public class ExtendedObservableCollection<T>: ObservableCollection<T>
{
    public void Execute(Action<IList<T>> itemsAction)
    {
        itemsAction(Items);
        OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
    }
}

And example how to use it:

MyDogs.Execute(items =>
{
    items.Clear();
    items.AddRange(Context.Dogs);
    items.Insert(0, new Dog { Id = 0, Name = "All Dogs" });
});

The Reset notification will be called only once after Execute is finished processing the underlying list.

require(vendor/autoload.php): failed to open stream

What you're missing is running composer install, which will import your packages and create the vendor folder, along with the autoload script.

Make sure your relative path is correct. For example the example scripts in PHPMailer are in examples/, below the project root, so the correct relative path to load the composer autoloader from there would be ../vendor/autoload.php.

The autoload.php you found in C:\Windows\SysWOW64\vendor\autoload.php is probably a global composer installation – where you'll usually put things like phpcs, phpunit, phpmd etc.

composer update is not the same thing, and probably not what you want to use. If your code is tested with your current package versions then running update may cause breakages which may require further work and testing, so don't run update unless you have a specific reason to and understand exactly what it means. To clarify further – you should probably only ever run composer update locally, never on your server as it is reasonably likely to break apps in production.

I often see complaints that people can't use composer because they can't run it on their server (e.g. because it's shared and they have no shell access). In that case, you can still use composer: run it locally (an environment that has no such restrictions), and upload the local vendor folder it generates along with all your other PHP scripts.

Running composer update also performs a composer install, and if you do not currently have a vendor folder (normal if you have a fresh checkout of a project), then it will create one, and also overwrite any composer.lock file you already have, updating package versions tagged in it, and this is what is potentially dangerous.

Similarly, if you do not currently have a composer.lock file (e.g. if it was not committed to the project), then composer install also effectively performs a composer update. It's thus vital to understand the difference between the two as they are definitely not interchangeable.

It is also possible to update a single package by naming it, for example:

composer update ramsey/uuid

This will re-resolve the version specified in your composer.json and install it in your vendor folder, and update your composer.lock file to match. This is far less likely to cause problems than a general composer update if you just need a specific update to one package.

It is normal for libraries to not include a composer.lock file of their own; it's up to apps to fix versions, not the libraries they use. As a result, library developers are expected to maintain compatibility with a wider range of host environments than app developers need to. For example, a library might be compatible with Laravel 5, 6, 7, and 8, but an app using it might require Laravel 8 for other reasons.

Composer 2.0 (out soon) should remove any remaining inconsistencies between install and update results.

How do I pipe a subprocess call to a text file?

The options for popen can be used in call

args, 
bufsize=0, 
executable=None, 
stdin=None, 
stdout=None, 
stderr=None, 
preexec_fn=None, 
close_fds=False, 
shell=False, 
cwd=None, 
env=None, 
universal_newlines=False, 
startupinfo=None, 
creationflags=0

So...

subprocess.call(["/home/myuser/run.sh", "/tmp/ad_xml",  "/tmp/video_xml"], stdout=myoutput)

Then you can do what you want with myoutput (which would need to be a file btw).

Also, you can do something closer to a piped output like this.

dmesg | grep hda

would be:

p1 = Popen(["dmesg"], stdout=PIPE)
p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)
output = p2.communicate()[0]

There's plenty of lovely, useful info on the python manual page.

App.Config file in console application C#

use this

System.Configuration.ConfigurationSettings.AppSettings.Get("Keyname")

How to change screen resolution of Raspberry Pi

Default Rpi resolution is : 1366x768 if i'm not mistaken.

You can change it though.

You will find all the information about it in this link.

http://elinux.org/RPiconfig

Search "hdmi mode" on that page.

Hope it helps.

c++ Read from .csv file

You can follow this answer to see many different ways to process CSV in C++.

In your case, the last call to getline is actually putting the last field of the first line and then all of the remaining lines into the variable genero. This is because there is no space delimiter found up until the end of file. Try changing the space character into a newline instead:

    getline(file, genero, file.widen('\n'));

or more succinctly:

    getline(file, genero);

In addition, your check for file.good() is premature. The last newline in the file is still in the input stream until it gets discarded by the next getline() call for ID. It is at this point that the end of file is detected, so the check should be based on that. You can fix this by changing your while test to be based on the getline() call for ID itself (assuming each line is well formed).

while (getline(file, ID, ',')) {
    cout << "ID: " << ID << " " ; 

    getline(file, nome, ',') ;
    cout << "User: " << nome << " " ;

    getline(file, idade, ',') ;
    cout << "Idade: " << idade << " "  ; 

    getline(file, genero);
    cout << "Sexo: " <<  genero<< " "  ;
}

For better error checking, you should check the result of each call to getline().

How do I deserialize a JSON string into an NSDictionary? (For iOS 5+)

NSData *data = [strChangetoJSON dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary *jsonResponse = [NSJSONSerialization JSONObjectWithData:data
                                                             options:kNilOptions
                                                               error:&error];

For example you have a NSString with special characters in NSString strChangetoJSON. Then you can convert that string to JSON response using above code.

What is @ModelAttribute in Spring MVC?

At the Method Level

1.When the annotation is used at the method level it indicates the purpose of that method is to add one or more model attributes

@ModelAttribute
public void addAttributes(Model model) {
model.addAttribute("india", "india");
}

At the Method Argument 1. When used as a method argument, it indicates the argument should be retrieved from the model. When not present and should be first instantiated and then added to the model and once present in the model, the arguments fields should be populated from all request parameters that have matching names So, it binds the form data with a bean.

 @RequestMapping(value = "/addEmployee", method = RequestMethod.POST)
  public String submit(@ModelAttribute("employee") Employee employee) {
  return "employeeView";
  }

How many bytes in a JavaScript string?

If you're using node.js, there is a simpler solution using buffers :

function getBinarySize(string) {
    return Buffer.byteLength(string, 'utf8');
}

There is a npm lib for that : https://www.npmjs.org/package/utf8-binary-cutter (from yours faithfully)

Writing a Python list of lists to a csv file

import csv
with open(file_path, 'a') as outcsv:   
    #configure writer to write standard csv file
    writer = csv.writer(outcsv, delimiter=',', quotechar='|', quoting=csv.QUOTE_MINIMAL, lineterminator='\n')
    writer.writerow(['number', 'text', 'number'])
    for item in list:
        #Write item to outcsv
        writer.writerow([item[0], item[1], item[2]])

official docs: http://docs.python.org/2/library/csv.html

How to do paging in AngularJS?

For anyone who find it difficult like me to create a paginator for a table I post this. So, in your view :

          <pagination total-items="total" items-per-page="itemPerPage"    ng-model="currentPage" ng-change="pageChanged()"></pagination>    
        <!-- To specify your choice of items Per Pages-->
     <div class="btn-group">
                <label class="btn btn-primary" ng-model="radioModel"  btn-radio="'Left'" data-ng-click="setItems(5)">5</label>
                <label class="btn btn-primary" ng-model="radioModel" btn-radio="'Middle'" data-ng-click="setItems(10)">10</label>
                <label class="btn btn-primary" ng-model="radioModel" btn-radio="'Right'" data-ng-click="setItems(15)">15</label>
            </div>
     //And don't forget in your table:
      <tr data-ng-repeat="p in profiles | offset: (currentPage-1)*itemPerPage | limitTo: itemPerPage" >

In your angularJs:

  var module = angular.module('myapp',['ui.bootstrap','dialogs']);
  module.controller('myController',function($scope,$http){
   $scope.total = $scope.mylist.length;     
   $scope.currentPage = 1;
   $scope.itemPerPage = 2;
   $scope.start = 0;

   $scope.setItems = function(n){
         $scope.itemPerPage = n;
   };
   // In case you can replace ($scope.currentPage - 1) * $scope.itemPerPage in <tr> by "start"
   $scope.pageChanged = function() {
        $scope.start = ($scope.currentPage - 1) * $scope.itemPerPage;
            };  
});
   //and our filter
     module.filter('offset', function() {
              return function(input, start) {
                start = parseInt(start, 10);
                return input.slice(start);
              };
            });     

How to Specify "Vary: Accept-Encoding" header in .htaccess

I guess it's meant that you enable gzip compression for your css and js files, because that will enable the client to receive both gzip-encoded content and a plain content.

This is how to do it in apache2:

<IfModule mod_deflate.c>
    #The following line is enough for .js and .css
    AddOutputFilter DEFLATE js css

    #The following line also enables compression by file content type, for the following list of Content-Type:s
    AddOutputFilterByType DEFLATE text/html text/plain text/xml application/xml

    #The following lines are to avoid bugs with some browsers
    BrowserMatch ^Mozilla/4 gzip-only-text/html
    BrowserMatch ^Mozilla/4\.0[678] no-gzip
    BrowserMatch \bMSIE !no-gzip !gzip-only-text/html 
</IfModule>

And here's how to add the Vary Accept-Encoding header: [src]

<IfModule mod_headers.c>
  <FilesMatch "\.(js|css|xml|gz)$">
    Header append Vary: Accept-Encoding
  </FilesMatch>
</IfModule>

The Vary: header tells the that the content served for this url will vary according to the value of a certain request header. Here it says that it will serve different content for clients who say they Accept-Encoding: gzip, deflate (a request header), than the content served to clients that do not send this header. The main advantage of this, AFAIK, is to let intermediate caching proxies know they need to have two different versions of the same url because of such change.

AJAX post error : Refused to set unsafe header "Connection"

Remove these two lines:

xmlHttp.setRequestHeader("Content-length", params.length);
xmlHttp.setRequestHeader("Connection", "close");

XMLHttpRequest isn't allowed to set these headers, they are being set automatically by the browser. The reason is that by manipulating these headers you might be able to trick the server into accepting a second request through the same connection, one that wouldn't go through the usual security checks - that would be a security vulnerability in the browser.

Action bar navigation modes are deprecated in Android L

The new Toolbar cannot be used for inflating multiple line objects, so it is impossible to add Tabs to it.
If you want to use a Toolbar like a TabWidget you can insert some Tab Objects to it, but only with the old Holo style.

Here there is a custom Library that uses v7 Toolbar like TabWidget with the new Material Design animations, but it uses the same methods from the old ActionBar Tabs, so you can attach your ViewPager to it.

What does Docker add to lxc-tools (the userspace LXC tools)?

Dockers use images which are build in layers. This adds a lot in terms of portability, sharing, versioning and other features. These images are very easy to port or transfer and since they are in layers, changes in subsequent versions are added in form of layers over previous layers. So, while porting many a times you don't need to port the base layers. Dockers have containers which run these images with execution environment contained, they add changes as new layers providing easy version control.

Apart from that Docker Hub is a good registry with thousands of public images, where you can find images which have OS and other softwares installed. So, you can get a pretty good head start for your application.

Is a Python dictionary an example of a hash table?

Yes. Internally it is implemented as open hashing based on a primitive polynomial over Z/2 (source).

Android adding simple animations while setvisibility(view.Gone)

Try adding this line to the xml parent layout

 android:animateLayoutChanges="true"

Your layout will look like this

<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:animateLayoutChanges="true"
    android:longClickable="false"
    android:orientation="vertical"
    android:weightSum="16">

    .......other code here

    </LinearLayout>

Is there any way to redraw tmux window when switching smaller monitor to bigger one?

ps ax | grep tmux
17685 pts/22   S+     0:00 tmux a -t 13g2
17920 pts/11   S+     0:00 tmux a -t 13g2
18065 pts/19   S+     0:00 grep tmux

kill the other one.