Programs & Examples On #Readprocessmemory

differences in application/json and application/x-www-form-urlencoded

The first case is telling the web server that you are posting JSON data as in:

{ Name : 'John Smith', Age: 23}

The second option is telling the web server that you will be encoding the parameters in the URL as in:

Name=John+Smith&Age=23

How to see my Eclipse version?

Help -> About Eclipse Platform

For Eclipse Mars - you can check Eclipse -> About Eclipse or Help -> Installation Details, then you should see the version:

enter image description here

Multi-character constant warnings

According to the standard (§6.4.4.4/10)

The value of an integer character constant containing more than one character (e.g., 'ab'), [...] is implementation-defined.

long x = '\xde\xad\xbe\xef'; // yes, single quotes

This is valid ISO 9899:2011 C. It compiles without warning under gcc with -Wall, and a “multi-character character constant” warning with -pedantic.

From Wikipedia:

Multi-character constants (e.g. 'xy') are valid, although rarely useful — they let one store several characters in an integer (e.g. 4 ASCII characters can fit in a 32-bit integer, 8 in a 64-bit one). Since the order in which the characters are packed into one int is not specified, portable use of multi-character constants is difficult.

For portability sake, don't use multi-character constants with integral types.

Getting the SQL from a Django QuerySet

Easy:

print my_queryset.query

For example:

from django.contrib.auth.models import User
print User.objects.filter(last_name__icontains = 'ax').query

It should also be mentioned that if you have DEBUG = True, then all of your queries are logged, and you can get them by accessing connection.queries:

from django.db import connections
connections['default'].queries

The django debug toolbar project uses this to present the queries on a page in a neat manner.

How to make HTML input tag only accept numerical values?

One way could be to have an array of allowed character codes and then use the Array.includes function to see if entered character is allowed.

Example:

<input type="text" onkeypress="return [45, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57].includes(event.charCode);"/>

Java generics - ArrayList initialization

You can't assign a List<Number> to a reference of type List<Integer> because List<Number> allows types of numbers other than Integer. If you were allowed to do that, the following would be allowed:

List<Number> numbers = new ArrayList<Number>();
numbers.add(1.1); // add a double
List<Integer> ints = numbers;
Integer fail = ints.get(0); // ClassCastException!

The type List<Integer> is making a guarantee that anything it contains will be an Integer. That's why you're allowed to get an Integer out of it without casting. As you can see, if the compiler allowed a List of another type such as Number to be assigned to a List<Integer> that guarantee would be broken.

Assigning a List<Integer> to a reference of a type such as List<?> or List<? extends Number> is legal because the ? means "some unknown subtype of the given type" (where the type is Object in the case of just ? and Number in the case of ? extends Number).

Since ? indicates that you do not know what specific type of object the List will accept, it isn't legal to add anything but null to it. You are, however, allowed to retrieve any object from it, which is the purpose of using a ? extends X bounded wildcard type. Note that the opposite is true for a ? super X bounded wildcard type... a List<? super Integer> is "a list of some unknown type that is at least a supertype of Integer". While you don't know exactly what type of List it is (could be List<Integer>, List<Number>, List<Object>) you do know for sure that whatever it is, an Integer can be added to it.

Finally, new ArrayList<?>() isn't legal because when you're creating an instance of a paramterized class like ArrayList, you have to give a specific type parameter. You could really use whatever in your example (Object, Foo, it doesn't matter) since you'll never be able to add anything but null to it since you're assigning it directly to an ArrayList<?> reference.

This Handler class should be static or leaks might occur: IncomingHandler

If IncomingHandler class is not static, it will have a reference to your Service object.

Handler objects for the same thread all share a common Looper object, which they post messages to and read from.

As messages contain target Handler, as long as there are messages with target handler in the message queue, the handler cannot be garbage collected. If handler is not static, your Service or Activity cannot be garbage collected, even after being destroyed.

This may lead to memory leaks, for some time at least - as long as the messages stay int the queue. This is not much of an issue unless you post long delayed messages.

You can make IncomingHandler static and have a WeakReference to your service:

static class IncomingHandler extends Handler {
    private final WeakReference<UDPListenerService> mService; 

    IncomingHandler(UDPListenerService service) {
        mService = new WeakReference<UDPListenerService>(service);
    }
    @Override
    public void handleMessage(Message msg)
    {
         UDPListenerService service = mService.get();
         if (service != null) {
              service.handleMessage(msg);
         }
    }
}

See this post by Romain Guy for further reference

Creating a class object in c++

In the first case you are creating the object on the heap using new. In the second case you are creating the object on the stack, so it will be disposed of when going out of scope. In C++ you'll need to delete objects on the heapexplicitly using delete when you don't Need them anymore.

To call a static method from a class, do

Singleton* singleton = Singleton::get_sample();

in your main-function or wherever.

Resize an Array while keeping current elements in Java?

Standard class java.util.ArrayList is resizable array, growing when new elements added.

Assertion failure in dequeueReusableCellWithIdentifier:forIndexPath:

In my case, the crash happened when I calleddeselectRowAtIndexPath:

The line was [tableView deselectRowAtIndexPath:indexPath animated:YES];

Changing it to [self.tableView deselectRowAtIndexPath:indexPath animated:YES]; FIXED MY PROBLEM!

Hope this helps anyone

Copying files from one directory to another in Java

Apache commons FileUtils will be handy, if you want only to move files from the source to target directory rather than copy the whole directory, you can do:

for (File srcFile: srcDir.listFiles()) {
    if (srcFile.isDirectory()) {
        FileUtils.copyDirectoryToDirectory(srcFile, dstDir);
    } else {
        FileUtils.copyFileToDirectory(srcFile, dstDir);
    }
}

If you want to skip directories, you can do:

for (File srcFile: srcDir.listFiles()) {
    if (!srcFile.isDirectory()) {
        FileUtils.copyFileToDirectory(srcFile, dstDir);
    }
}

Set Culture in an ASP.Net MVC app

I would do it in the Initialize event of the controller like this...

    protected override void Initialize(System.Web.Routing.RequestContext requestContext)
    {
        base.Initialize(requestContext);

        const string culture = "en-US";
        CultureInfo ci = CultureInfo.GetCultureInfo(culture);

        Thread.CurrentThread.CurrentCulture = ci;
        Thread.CurrentThread.CurrentUICulture = ci;
    }

Converting VS2012 Solution to VS2010

Solution of VS2010 is supported by VS2012. Solution of VS2012 isn't supported by VS2010 --> one-way upgrade only. VS2012 doesn't support setup projects. Find here more about VS2010/VS2012 compatibility: http://msdn.microsoft.com/en-us/library/hh266747(v=vs.110).aspx

Crystal Reports - Adding a parameter to a 'Command' query

When you are in the Command, click Create to create a new parameter; call it project_name. Once you've created it, double click its name to add it to the command's text. You query should resemble:

SELECT Projecttname, ReleaseDate, TaskName
FROM DB_Table
WHERE Project_Name LIKE {?project_name} + '*'
AND ReleaseDate >= getdate() --assumes sql server

If desired, link the main report to the subreport on this ({?project_name}) field. If you don't establish a link between the main and subreport, CR will prompt you for the subreport's parameter.

In versions prior to 2008, a command's parameter was only allowed to be a scalar value.

How to set session timeout dynamically in Java web applications?

As another anwsers told, you can change in a Session Listener. But you can change it directly in your servlet, for example.

getRequest().getSession().setMaxInactiveInterval(123);

Proper way to initialize C++ structs

From what you've told us it does appear to be a false positive in valgrind. The new syntax with () should value-initialize the object, assuming it is POD.

Is it possible that some subpart of your struct isn't actually POD and that's preventing the expected initialization? Are you able to simplify your code into a postable example that still flags the valgrind error?

Alternately perhaps your compiler doesn't actually value-initialize POD structures.

In any case probably the simplest solution is to write constructor(s) as needed for the struct/subparts.

CSS display: inline vs inline-block

Inline elements:

  1. respect left & right margins and padding, but not top & bottom
  2. cannot have a width and height set
  3. allow other elements to sit to their left and right.
  4. see very important side notes on this here.

Block elements:

  1. respect all of those
  2. force a line break after the block element
  3. acquires full-width if width not defined

Inline-block elements:

  1. allow other elements to sit to their left and right
  2. respect top & bottom margins and padding
  3. respect height and width

From W3Schools:

  • An inline element has no line break before or after it, and it tolerates HTML elements next to it.

  • A block element has some whitespace above and below it and does not tolerate any HTML elements next to it.

  • An inline-block element is placed as an inline element (on the same line as adjacent content), but it behaves as a block element.

When you visualize this, it looks like this:

CSS block vs inline vs inline-block

The image is taken from this page, which also talks some more about this subject.

Output ("echo") a variable to a text file

Your sample code seems to be OK. Thus, the root problem needs to be dug up somehow. Let's eliminate chance for typos in the script. First off, make sure you put Set-Strictmode -Version 2.0 in the beginning of your script. This will help you to catch misspelled variable names. Like so,

# Test.ps1
set-strictmode -version 2.0 # Comment this line and no error will be reported.
$foo = "bar"
set-content -path ./test.txt -value $fo # Error! Should be "$foo"

PS C:\temp> .\test.ps1
The variable '$fo' cannot be retrieved because it has not been set.
At C:\temp\test.ps1:3 char:40
+ set-content -path ./test.txt -value $fo <<<<
    + CategoryInfo          : InvalidOperation: (fo:Token) [], RuntimeException
    + FullyQualifiedErrorId : VariableIsUndefined

The next part about question marks sounds like you have a problem with Unicode. What's the output when you type the file with Powershell like so,

$file = "\\server\share\file.txt"
cat $file

Why doesn't RecyclerView have onItemClickListener()?

 main_recyclerview.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {
        @Override
        public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e)
        {
            int position=rv.getChildAdapterPosition(rv.findChildViewUnder(e.getX(),e.getY()));

            switch (position)
            {
                case 0:
                {
                    wifi(position);
                    adapter2.notifyDataSetChanged();
                }
                break;

                case 1:
                {
                    sound(position);
                    adapter2.notifyDataSetChanged();
                }
                break;

                case 2:
                {
                    bluetooth(position);
                    adapter2.notifyDataSetChanged();
                }
                break;


            }
            return true;
        }

        @Override
        public void onTouchEvent(RecyclerView rv, MotionEvent e)
        {

        }

        @Override
        public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {

        }
    });

Is there a way to remove the separator line from a UITableView?

In the ViewDidLoad Method, you have to write this line.

tableViews.separatorStyle = UITableViewCellSeparatorStyleNone;

This is working Code.

A CSS selector to get last visible div

This worked for me.

.alert:not(:first-child){
    margin: 30px;
}

prevent iphone default keyboard when focusing an <input>

You can add a callback function to your DatePicker to tell it to blur the input field before showing the DatePicker.

$('.selector').datepicker({
   beforeShow: function(){$('input').blur();}
});

Note: The iOS keyboard will appear for a fraction of a second and then hide.

How to run TestNG from command line

You will need to use semicolon as delimiter while specifying the jar and class file path in windows. This solved the issue.
Assuming the class file is under C:.

java -cp ".;C:\testng.jar" org.testng.TestNG testing.xml

Max retries exceeded with URL in requests

Adding my own experience for those who are experiencing this in the future. My specific error was

Failed to establish a new connection: [Errno 8] nodename nor servname provided, or not known'

It turns out that this was actually because I had reach the maximum number of open files on my system. It had nothing to do with failed connections, or even a DNS error as indicated.

Correct MySQL configuration for Ruby on Rails Database.yml file

If you have multiple databases for testing and development this might help

development:
  adapter: mysql2
  encoding: utf8
  reconnect: false
  database: DBNAME
  pool: 5
  username: usr
  password: paswd
  shost: localhost
test:
  adapter: mysql2
  encoding: utf8
  reconnect: false
  database: DBNAME
  pool: 5
  username: usr
  password: paswd
  shost: localhost
production:
  adapter: mysql2
  encoding: utf8
  reconnect: false
  database: DBNAME
  pool: 5
  username: usr
  password: paswd
  shost: localhost

How to remove border from specific PrimeFaces p:panelGrid?

The border is been set on the generated tr and td elements, not on the table. So, this should do:

.companyHeaderGrid.ui-panelgrid>*>tr,
.companyHeaderGrid.ui-panelgrid .ui-panelgrid-cell {
    border: none;
}

How I found it? Just check the generated HTML output and all CSS style rules in the webdeveloper toolset of Chrome (rightclick, Inspect Element or press F12). Firebug and IE9 have a similar toolset. As to the confusion, just keep in mind that JSF/Facelets ultimately generates HTML and that CSS only applies on the HTML markup, not on the JSF source code. So to apply/finetune CSS you need to look in the client (webbrowser) side instead.

enter image description here

See also:


If you're still on PrimeFaces 4 or older, use below instead:

.companyHeaderGrid.ui-panelgrid>*>tr,
.companyHeaderGrid.ui-panelgrid>*>tr>td {
    border: none;
}

Android : How to set onClick event for Button in List item of ListView

This has been discussed in many posts but still I could not figure out a solution with:

android:focusable="false"
android:focusableInTouchMode="false"
android:focusableInTouchMode="false"

Below solution will work with any of the ui components : Button, ImageButtons, ImageView, Textview. LinearLayout, RelativeLayout clicks inside a listview cell and also will respond to onItemClick:

Adapter class - getview():

    @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View view = convertView;
            if (view == null) {
                view = lInflater.inflate(R.layout.my_ref_row, parent, false);
            }
            final Organization currentOrg = organizationlist.get(position).getOrganization();

            TextView name = (TextView) view.findViewById(R.id.name);
            Button btn = (Button) view.findViewById(R.id.btn_check);
            btn.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    context.doSelection(currentOrg);

                }
            });

       if(currentOrg.isSelected()){
            btn.setBackgroundResource(R.drawable.sub_search_tick);
        }else{
            btn.setBackgroundResource(R.drawable.sub_search_tick_box);
        }

    }

In this was you can get the button clicked object to the activity. (Specially when you want the button to act as a check box with selected and non-selected states):

    public void doSelection(Organization currentOrg) {
        Log.e("Btn clicked ", currentOrg.getOrgName());
        if (currentOrg.isSelected() == false) {
            currentOrg.setSelected(true);
        } else {
            currentOrg.setSelected(false);
        }
        adapter.notifyDataSetChanged();

    }

How can I add or update a query string parameter?

Here is a shorter version that takes care of

  • query with or without a given parameter
  • query with multiple parameter values
  • query containing hash

Code:

var setQueryParameter = function(uri, key, value) {
  var re = new RegExp("([?&])("+ key + "=)[^&#]*", "g");
  if (uri.match(re)) 
    return uri.replace(re, '$1$2' + value);

  // need to add parameter to URI
  var paramString = (uri.indexOf('?') < 0 ? "?" : "&") + key + "=" + value;
  var hashIndex = uri.indexOf('#');
  if (hashIndex < 0)
    return uri + paramString;
  else
    return uri.substring(0, hashIndex) + paramString + uri.substring(hashIndex);
}

The regex description can be found here.

NOTE: This solution is based on @amateur answer, but with many improvements.

Standard deviation of a list

Using python, here are few methods:

import statistics as st

n = int(input())
data = list(map(int, input().split()))

Approach1 - using a function

stdev = st.pstdev(data)

Approach2: calculate variance and take square root of it

variance = st.pvariance(data)
devia = math.sqrt(variance)

Approach3: using basic math

mean = sum(data)/n
variance = sum([((x - mean) ** 2) for x in X]) / n
stddev = variance ** 0.5

print("{0:0.1f}".format(stddev))

Note:

  • variance calculates variance of sample population
  • pvariance calculates variance of entire population
  • similar differences between stdev and pstdev

Add a custom attribute to a Laravel / Eloquent model on load?

Step 1: Define attributes in $appends
Step 2: Define accessor for that attributes.
Example:

<?php
...

class Movie extends Model{

    protected $appends = ['cover'];

    //define accessor
    public function getCoverAttribute()
    {
        return json_decode($this->InJson)->cover;
    }

Modifying Objects within stream in Java8 while iterating

Yes, you can modify state of objects inside your stream, but most often you should avoid modifying state of source of stream. From non-interference section of stream package documentation we can read that:

For most data sources, preventing interference means ensuring that the data source is not modified at all during the execution of the stream pipeline. The notable exception to this are streams whose sources are concurrent collections, which are specifically designed to handle concurrent modification. Concurrent stream sources are those whose Spliterator reports the CONCURRENT characteristic.

So this is OK

  List<User> users = getUsers();
  users.stream().forEach(u -> u.setProperty(value));
//                       ^    ^^^^^^^^^^^^^

but this in most cases is not

  users.stream().forEach(u -> users.remove(u));
//^^^^^                       ^^^^^^^^^^^^

and may throw ConcurrentModificationException or even other unexpected exceptions like NPE:

List<Integer> list = IntStream.range(0, 10).boxed().collect(Collectors.toList());

list.stream()
    .filter(i -> i > 5)
    .forEach(i -> list.remove(i));  //throws NullPointerException

Filter element based on .data() key/value

your filter would work, but you need to return true on matching objects in the function passed to the filter for it to grab them.

var $previous = $('.navlink').filter(function() { 
  return $(this).data("selected") == true 
});

Formatting DataBinder.Eval data

After some searching on the Internet I found that it is in fact very much possible to call a custom method passing the DataBinder.Eval value.

The custom method can be written in the code behind file, but has to be declared public or protected. In my question above, I had mentioned that I tried to write the custom method in the code behind but was getting a run time error. The reason for this was that I had declared the method to be private.

So, in summary the following is a good way to use DataBinder.Eval value to get your desired output:

default.aspx

<asp:Label ID="lblNewsDate" runat="server" Text='<%# GetDateInHomepageFormat(DataBinder.Eval(Container.DataItem, "publishedDate")) )%>'></asp:Label>

default.aspx.cs code:

public partial class _Default : System.Web.UI.Page
{

    protected string GetDateInHomepageFormat(DateTime d)
    {

        string retValue = "";

        // Do all processing required and return value

        return retValue;
    }
}

Hope this helps others as well.

How to apply shell command to each line of a command output?

i like to use gawk for running multiple commands on a list, for instance

ls -l | gawk '{system("/path/to/cmd.sh "$1)}'

however the escaping of the escapable characters can get a little hairy.

Javascript: Load an Image from url and display

You have to right idea generating the url based off of the input value. The only issue is you are using window.location.href. Setting window.location.href changes the url of the current window. What you probably want to do is change the src attribute of an image.

<html>
<body>
<form>
  <input type="text" value="" id="imagename">
  <input type="button" onclick="var image = document.getElementById('the-image'); image.src='http://webpage.com/images/'+document.getElementById('imagename').value +'.png'" value="GO">
</form>
<img id="the-image">
</body>
</html>

HTML5 video (mp4 and ogv) problems in Safari and Firefox - but Chrome is all good

Just need to change one letter:), rename 640x360.ogv to 640x360.ogg, it will work for all the 3 browers.

java.lang.ClassNotFoundException: javax.servlet.jsp.jstl.core.Config

I had the same problem. Go to Project Properties -> Deployment Assemplbly and add jstl jar

LaTeX: Multiple authors in a two-column article

I put together a little test here:

\documentclass[10pt,twocolumn]{article}

\title{Article Title}
\author{
    First Author\\
    Department\\
    school\\
    email@edu
  \and
    Second Author\\
    Department\\
    school\\
    email@edu
    \and
    Third Author\\
    Department\\
    school\\
    email@edu
    \and
    Fourth Author\\
    Department\\
    school\\
    email@edu
}
\date{\today}

\begin{document}

\maketitle

\begin{abstract}
\ldots
\end{abstract}

\section{Introduction}
\ldots

\end{document}

Things to note, the title, author and date fields are declared before \begin{document}. Also, the multicol package is likely unnecessary in this case since you have declared twocolumn in the document class.

This example puts all four authors on the same line, but if your authors have longer names, departments or emails, this might cause it to flow over onto another line. You might be able to change the font sizes around a little bit to make things fit. This could be done by doing something like {\small First Author}. Here's a more detailed article on \LaTeX font sizes:

https://engineering.purdue.edu/ECN/Support/KB/Docs/LaTeXChangingTheFont

To italicize you can use {\it First Name} or \textit{First Name}.

Be careful though, if the document is meant for publication often times journals or conference proceedings have their own formatting guidelines so font size trickery might not be allowed.

How to fire AJAX request Periodically?

I tried the below code,

    function executeQuery() {
  $.ajax({
    url: 'url/path/here',
    success: function(data) {
      // do something with the return value here if you like
    }
  });
  setTimeout(executeQuery, 5000); // you could choose not to continue on failure...
}

$(document).ready(function() {
  // run the first time; all subsequent calls will take care of themselves
  setTimeout(executeQuery, 5000);
});

This didn't work as expected for the specified interval,the page didn't load completely and the function was been called continuously. Its better to call setTimeout(executeQuery, 5000); outside executeQuery() in a separate function as below,

function executeQuery() {
  $.ajax({
    url: 'url/path/here',
    success: function(data) {
      // do something with the return value here if you like
    }
  });
  updateCall();
}

function updateCall(){
setTimeout(function(){executeQuery()}, 5000);
}

$(document).ready(function() {
  executeQuery();
});

This worked exactly as intended.

Query a parameter (postgresql.conf setting) like "max_connections"

You can use SHOW:

SHOW max_connections;

This returns the currently effective setting. Be aware that it can differ from the setting in postgresql.conf as there are a multiple ways to set run-time parameters in PostgreSQL. To reset the "original" setting from postgresql.conf in your current session:

RESET max_connections;

However, not applicable to this particular setting. The manual:

This parameter can only be set at server start.

To see all settings:

SHOW ALL;

There is also pg_settings:

The view pg_settings provides access to run-time parameters of the server. It is essentially an alternative interface to the SHOW and SET commands. It also provides access to some facts about each parameter that are not directly available from SHOW, such as minimum and maximum values.

For your original request:

SELECT *
FROM   pg_settings
WHERE  name = 'max_connections';

Finally, there is current_setting(), which can be nested in DML statements:

SELECT current_setting('max_connections');

Related:

How to tell if a string is not defined in a Bash shell script

I think the answer you are after is implied (if not stated) by Vinko's answer, though it is not spelled out simply. To distinguish whether VAR is set but empty or not set, you can use:

if [ -z "${VAR+xxx}" ]; then echo VAR is not set at all; fi
if [ -z "$VAR" ] && [ "${VAR+xxx}" = "xxx" ]; then echo VAR is set but empty; fi

You probably can combine the two tests on the second line into one with:

if [ -z "$VAR" -a "${VAR+xxx}" = "xxx" ]; then echo VAR is set but empty; fi

However, if you read the documentation for Autoconf, you'll find that they do not recommend combining terms with '-a' and do recommend using separate simple tests combined with &&. I've not encountered a system where there is a problem; that doesn't mean they didn't used to exist (but they are probably extremely rare these days, even if they weren't as rare in the distant past).

You can find the details of these, and other related shell parameter expansions, the test or [ command and conditional expressions in the Bash manual.


I was recently asked by email about this answer with the question:

You use two tests, and I understand the second one well, but not the first one. More precisely I don't understand the need for variable expansion

if [ -z "${VAR+xxx}" ]; then echo VAR is not set at all; fi

Wouldn't this accomplish the same?

if [ -z "${VAR}" ]; then echo VAR is not set at all; fi

Fair question - the answer is 'No, your simpler alternative does not do the same thing'.

Suppose I write this before your test:

VAR=

Your test will say "VAR is not set at all", but mine will say (by implication because it echoes nothing) "VAR is set but its value might be empty". Try this script:

(
unset VAR
if [ -z "${VAR+xxx}" ]; then echo JL:1 VAR is not set at all; fi
if [ -z "${VAR}" ];     then echo MP:1 VAR is not set at all; fi
VAR=
if [ -z "${VAR+xxx}" ]; then echo JL:2 VAR is not set at all; fi
if [ -z "${VAR}" ];     then echo MP:2 VAR is not set at all; fi
)

The output is:

JL:1 VAR is not set at all
MP:1 VAR is not set at all
MP:2 VAR is not set at all

In the second pair of tests, the variable is set, but it is set to the empty value. This is the distinction that the ${VAR=value} and ${VAR:=value} notations make. Ditto for ${VAR-value} and ${VAR:-value}, and ${VAR+value} and ${VAR:+value}, and so on.


As Gili points out in his answer, if you run bash with the set -o nounset option, then the basic answer above fails with unbound variable. It is easily remedied:

if [ -z "${VAR+xxx}" ]; then echo VAR is not set at all; fi
if [ -z "${VAR-}" ] && [ "${VAR+xxx}" = "xxx" ]; then echo VAR is set but empty; fi

Or you could cancel the set -o nounset option with set +u (set -u being equivalent to set -o nounset).

How to make jQuery UI nav menu horizontal?

changing:

.ui-menu .ui-menu-item { 
    margin: 0; 
    padding: 0; 
    zoom: 1; 
    width: 100%; 
}

to:

.ui-menu .ui-menu-item { 
    margin: 0; 
    padding: 0; 
    zoom: 1; 
    width: auto; 
    float:left; 
 }

should start you off.

How do I remove the "extended attributes" on a file in Mac OS X?

Removing a Single Attribute on a Single File

See Bavarious's answer.


To Remove All Extended Attributes On a Single File

Use xattr with the -c flag to "clear" the attributes:

xattr -c yourfile.txt



To Remove All Extended Attributes On Many Files

To recursively remove extended attributes on all files in a directory, combine the -c "clear" flag with the -r recursive flag:

xattr -rc /path/to/directory



A Tip for Mac OS X Users

Have a long path with spaces or special characters?

Open Terminal.app and start typing xattr -rc, include a trailing space, and then then drag the file or folder to the Terminal.app window and it will automatically add the full path with proper escaping.

How to include header files in GCC search path?

Try gcc -c -I/home/me/development/skia sample.c.

Postgres password authentication fails

Assuming, that you have root access on the box you can do:

sudo -u postgres psql

If that fails with a database "postgres" does not exists this block.

sudo -u postgres psql template1

Then sudo nano /etc/postgresql/11/main/pg_hba.conf file

local   all         postgres                          ident

For newer versions of PostgreSQL ident actually might be peer.

Inside the psql shell you can give the DB user postgres a password:

ALTER USER postgres PASSWORD 'newPassword';

Compare if BigDecimal is greater than zero

Use compareTo() function that's built into the class.

Reading input files by line using read command in shell scripting skips last line

read reads until it finds a newline character or the end of file, and returns a non-zero exit code if it encounters an end-of-file. So it's quite possible for it to both read a line and return a non-zero exit code.

Consequently, the following code is not safe if the input might not be terminated by a newline:

while read LINE; do
  # do something with LINE
done

because the body of the while won't be executed on the last line.

Technically speaking, a file not terminated with a newline is not a text file, and text tools may fail in odd ways on such a file. However, I'm always reluctant to fall back on that explanation.

One way to solve the problem is to test if what was read is non-empty (-n):

while read -r LINE || [[ -n $LINE ]]; do
  # do something with LINE
done

Other solutions include using mapfile to read the file into an array, piping the file through some utility which is guaranteed to terminate the last line properly (grep ., for example, if you don't want to deal with blank lines), or doing the iterative processing with a tool like awk (which is usually my preference).

Note that -r is almost certainly needed in the read builtin; it causes read to not reinterpret \-sequences in the input.

Hide all warnings in ipython

I hide the warnings in the pink boxes by running the following code in a cell:

from IPython.display import HTML
HTML('''<script>
code_show_err=false; 
function code_toggle_err() {
 if (code_show_err){
 $('div.output_stderr').hide();
 } else {
 $('div.output_stderr').show();
 }
 code_show_err = !code_show_err
} 
$( document ).ready(code_toggle_err);
</script>
To toggle on/off output_stderr, click <a href="javascript:code_toggle_err()">here</a>.''')

Include headers when using SELECT INTO OUTFILE?

Here is a way to get the header titles from the column names dynamically.

/* Change table_name and database_name */
SET @table_name = 'table_name';
SET @table_schema = 'database_name';
SET @default_group_concat_max_len = (SELECT @@group_concat_max_len);

/* Sets Group Concat Max Limit larger for tables with a lot of columns */
SET SESSION group_concat_max_len = 1000000;

SET @col_names = (
  SELECT GROUP_CONCAT(QUOTE(`column_name`)) AS columns
  FROM information_schema.columns
  WHERE table_schema = @table_schema
  AND table_name = @table_name);

SET @cols = CONCAT('(SELECT ', @col_names, ')');

SET @query = CONCAT('(SELECT * FROM ', @table_schema, '.', @table_name,
  ' INTO OUTFILE \'/tmp/your_csv_file.csv\'
  FIELDS ENCLOSED BY \'\\\'\' TERMINATED BY \'\t\' ESCAPED BY \'\'
  LINES TERMINATED BY \'\n\')');

/* Concatenates column names to query */
SET @sql = CONCAT(@cols, ' UNION ALL ', @query);

/* Resets Group Contact Max Limit back to original value */
SET SESSION group_concat_max_len = @default_group_concat_max_len;

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

Python 2,3 Convert Integer to "bytes" Cleanly

I have found the only reliable, portable method to be

bytes(bytearray([n]))

Just bytes([n]) does not work in python 2. Taking the scenic route through bytearray seems like the only reasonable solution.

Pylint, PyChecker or PyFlakes?

pep8 was recently added to PyPi.

  • pep8 - Python style guide checker
  • pep8 is a tool to check your Python code against some of the style conventions in PEP 8.

It is now super easy to check your code against pep8.

See http://pypi.python.org/pypi/pep8

Multiple types were found that match the controller named 'Home'

In MVC4 & MVC5 It is little bit different, use following

/App_Start/RouteConfig.cs

namespace MyNamespace
{
    public class RouteConfig
    {
        public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

            routes.MapRoute(
                name: "Default",
                url: "{controller}/{action}/{id}",
                defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional },
                namespaces:  new[] {"MyNamespace.Controllers"}
            );
        }
    }
}

and in Areas

context.MapRoute(
                "Admin_default",
                "Admin/{controller}/{action}/{id}",
                new { action = "Index", id = UrlParameter.Optional },
                new[] { "MyNamespace.Areas.Admin.Controllers" }
            );

How to validate a url in Python? (Malformed or not)

Not directly relevant, but often it's required to identify whether some token CAN be a url or not, not necessarily 100% correctly formed (ie, https part omitted and so on). I've read this post and did not find the solution, so I am posting my own here for the sake of completeness.

def get_domain_suffixes():
    import requests
    res=requests.get('https://publicsuffix.org/list/public_suffix_list.dat')
    lst=set()
    for line in res.text.split('\n'):
        if not line.startswith('//'):
            domains=line.split('.')
            cand=domains[-1]
            if cand:
                lst.add('.'+cand)
    return tuple(sorted(lst))

domain_suffixes=get_domain_suffixes()

def reminds_url(txt:str):
    """
    >>> reminds_url('yandex.ru.com/somepath')
    True
    
    """
    ltext=txt.lower().split('/')[0]
    return ltext.startswith(('http','www','ftp')) or ltext.endswith(domain_suffixes)

How to remove all CSS classes using jQuery/JavaScript?

Just set the className attribute of the real DOM element to '' (nothing).

$('#item')[0].className = ''; // the real DOM element is at [0]

Edit: Other people have said that just calling removeClass works - I tested this with the Google JQuery Playground: http://savedbythegoog.appspot.com/?id=ag5zYXZlZGJ5dGhlZ29vZ3ISCxIJU2F2ZWRDb2RlGIS61gEM ... and it works. So you can also do it this way:

$("#item").removeClass();

How to create a testflight invitation code?

after you add the user for testing. the user should get an email. open that email by your iOS device, then click "Start testing" it will bring you to testFlight to download the app directly. If you open that email via computer, and then click "Start testing" it will show you another page which have the instruction of how to install the app. and that invitation code is on the last line. those All upper case letters is the code.

SELECT data from another schema in oracle

Depending on the schema/account you are using to connect to the database, I would suspect you are missing a grant to the account you are using to connect to the database.

Connect as PCT account in the database, then grant the account you are using select access for the table.

grant select on pi_int to Account_used_to_connect

Is there any way to wait for AJAX response and halt execution?

Try this code. it worked for me.

 function getInvoiceID(url, invoiceId) {
    return $.ajax({
        type: 'POST',
        url: url,
        data: { invoiceId: invoiceId },
        async: false,
    });
}
function isInvoiceIdExists(url, invoiceId) {
    $.when(getInvoiceID(url, invoiceId)).done(function (data) {
        if (!data) {

        }
    });
}

How to replace a whole line with sed?

Try this:

sed "s/aaa=.*/aaa=xxx/g"

Redraw datatables after using ajax to refresh the table content?

It looks as if you could use the API functions to

  • clear the table ( fnClearTable )
  • add new data to the table ( fnAddData)
  • redraw the table ( fnDraw )

http://datatables.net/api

UPDATE

I guess you're using the DOM Data Source (for server-side processing) to generate your table. I didn't really get that at first, so my previous answer won't work for that.

To get it to work without rewriting your server side code:

What you'll need to do is totally remove the old table (in the dom) and replace it with the ajax result content, then reinitialize the datatable:

// in your $.post callback:

function (data) {

    // remove the old table
    $("#ajaxresponse").children().remove();

    // replace with the new table
    $("#ajaxresponse").html(data);

    // reinitialize the datatable
    $('#rankings').dataTable( {
    "sDom":'t<"bottom"filp><"clear">',
    "bAutoWidth": false,
    "sPaginationType": "full_numbers",
        "aoColumns": [ 
        { "bSortable": false, "sWidth": "10px" },
        null,
        null,
        null,
        null,
        null,
        null,
        null,
        null,
        null,
        null,
        null
        ]

    } 
    );
}

Regular expression for validating names and surnames?

This one should work ^([A-Z]{1}+[a-z\-\.\']*+[\s]?)* Add some special characters if you need them.

Detect if a NumPy array contains at least one non-numeric value?

Pfft! Microseconds! Never solve a problem in microseconds that can be solved in nanoseconds.

Note that the accepted answer:

  • iterates over the whole data, regardless of whether a nan is found
  • creates a temporary array of size N, which is redundant.

A better solution is to return True immediately when NAN is found:

import numba
import numpy as np

NAN = float("nan")

@numba.njit(nogil=True)
def _any_nans(a):
    for x in a:
        if np.isnan(x): return True
    return False

@numba.jit
def any_nans(a):
    if not a.dtype.kind=='f': return False
    return _any_nans(a.flat)

array1M = np.random.rand(1000000)
assert any_nans(array1M)==False
%timeit any_nans(array1M)  # 573us

array1M[0] = NAN
assert any_nans(array1M)==True
%timeit any_nans(array1M)  # 774ns  (!nanoseconds)

and works for n-dimensions:

array1M_nd = array1M.reshape((len(array1M)/2, 2))
assert any_nans(array1M_nd)==True
%timeit any_nans(array1M_nd)  # 774ns

Compare this to the numpy native solution:

def any_nans(a):
    if not a.dtype.kind=='f': return False
    return np.isnan(a).any()

array1M = np.random.rand(1000000)
assert any_nans(array1M)==False
%timeit any_nans(array1M)  # 456us

array1M[0] = NAN
assert any_nans(array1M)==True
%timeit any_nans(array1M)  # 470us

%timeit np.isnan(array1M).any()  # 532us

The early-exit method is 3 orders or magnitude speedup (in some cases). Not too shabby for a simple annotation.

How to draw text using only OpenGL methods?

Theory

Why it is hard

Popular font formats like TrueType and OpenType are vector outline formats: they use Bezier curves to define the boundary of the letter.

Image source.

Transforming those formats into arrays of pixels (rasterization) is too specific and out of OpenGL's scope, specially because OpenGl does not have non-straight primitives (e.g. see Why is there no circle or ellipse primitive in OpenGL?)

The easiest approach is to first raster fonts ourselves on the CPU, and then give the array of pixels to OpenGL as a texture.

OpenGL then knows how to deal with arrays of pixels through textures very well.

Texture atlas

We could raster characters for every frame and re-create the textures, but that is not very efficient, specially if characters have a fixed size.

The more efficient approach is to raster all characters you plan on using and cram them on a single texture.

And then transfer that to the GPU once, and use it texture with custom uv coordinates to choose the right character.

This approach is called a texture atlas and it can be used not only for textures but also other repeatedly used textures, like tiles in a 2D game or web UI icons.

The Wikipedia picture of the full texture, which is itself taken from freetype-gl, illustrates this well:

I suspect that optimizing character placement to the smallest texture problem is an NP-hard problem, see: What algorithm can be used for packing rectangles of different sizes into the smallest rectangle possible in a fairly optimal way?

The same technique is used in web development to transmit several small images (like icons) at once, but there it is called "CSS Sprites": https://css-tricks.com/css-sprites/ and are used to hide the latency of the network instead of that of the CPU / GPU communication.

Non-CPU raster methods

There also exist methods which don't use the CPU raster to textures.

CPU rastering is simple because it uses the GPU as little as possible, but we also start thinking if it would be possible to use the GPU efficiency further.

This FOSDEM 2014 video explains other existing techniques:

Fonts inside of the 3D geometry with perspective

Rendering fonts inside of the 3D geometry with perspective (compared to an orthogonal HUD) is much more complicated, because perspective could make one part of the character much closer to the screen and larger than the other, making an uniform CPU discretization (e.g. raster, tesselation) look bad on the close part. This is actually an active research topic:

enter image description here

Distance fields are one of the popular techniques now.

Implementations

The examples that follow were all tested on Ubuntu 15.10.

Because this is a complex problem as discussed previously, most examples are large, and would blow up the 30k char limit of this answer, so just clone the respective Git repositories to compile.

They are all fully open source however, so you can just RTFS.

FreeType solutions

FreeType looks like the dominant open source font rasterization library, so it would allow us to use TrueType and OpenType fonts, making it the most elegant solution.

Examples / tutorials:

Other font rasterizers

Those seem less good than FreeType, but may be more lightweight:

Anton's OpenGL 4 Tutorials example 26 "Bitmap fonts"

The font was created by the author manually and stored in a single .png file. Letters are stored in an array form inside the image.

This method is of course not very general, and you would have difficulties with internationalization.

Build with:

make -f Makefile.linux64

Output preview:

enter image description here

opengl-tutorial chapter 11 "2D fonts"

Textures are generated from DDS files.

The tutorial explains how the DDS files were created, using CBFG and Paint.Net.

Output preview:

enter image description here

For some reason Suzanne is missing for me, but the time counter works fine: https://github.com/opengl-tutorials/ogl/issues/15

FreeGLUT

GLUT has glutStrokeCharacter and FreeGLUT is open source... https://github.com/dcnieho/FreeGLUT/blob/FG_3_0_0/src/fg_font.c#L255

OpenGLText

https://github.com/tlorach/OpenGLText

TrueType raster. By NVIDIA employee. Aims for reusability. Haven't tried it yet.

ARM Mali GLES SDK Sample

http://malideveloper.arm.com/resources/sample-code/simple-text-rendering/ seems to encode all characters on a PNG, and cut them from there.

SDL_ttf

enter image description here

Source: https://github.com/cirosantilli/cpp-cheat/blob/d36527fe4977bb9ef4b885b1ec92bd0cd3444a98/sdl/ttf.c

Lives in a separate tree to SDL, and integrates easily.

Does not provide a texture atlas implementation however, so performance will be limited: How to render fonts and text with SDL2 efficiently?

Related threads

How to clear File Input

Clear file input with jQuery

$("#fileInputId").val(null);

Clear file input with JavaScript

document.getElementById("fileInputId").value = null;

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

Just put the following code on the top of the page

@{
    Layout = "";
}

Converting date between DD/MM/YYYY and YYYY-MM-DD?

Does anyone else else think it's a waste to convert these strings to date/time objects for what is, in the end, a simple text transformation? If you're certain the incoming dates will be valid, you can just use:

>>> ddmmyyyy = "21/12/2008"
>>> yyyymmdd = ddmmyyyy[6:] + "-" + ddmmyyyy[3:5] + "-" + ddmmyyyy[:2]
>>> yyyymmdd
'2008-12-21'

This will almost certainly be faster than the conversion to and from a date.

Get hours difference between two dates in Moment Js

var __startTime = moment("2016-06-06T09:00").format();
var __endTime = moment("2016-06-06T21:00").format();

var __duration = moment.duration(moment(__endTime).diff(__startTime));
var __hours = __duration.asHours();
console.log(__hours);

How do I get the "id" after INSERT into MySQL database with Python?

SELECT @@IDENTITY AS 'Identity';

or

SELECT last_insert_id();

WITH (NOLOCK) vs SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED

They are the same thing. If you use the set transaction isolation level statement, it will apply to all the tables in the connection, so if you only want a nolock on one or two tables use that; otherwise use the other.

Both will give you dirty reads. If you are okay with that, then use them. If you can't have dirty reads, then consider snapshot or serializable hints instead.

Programmatically add custom event in the iPhone Calendar

Swift 4.0 implementation :

use import in top of page by import EventKit

then

@IBAction func addtoCalendarClicked(sender: AnyObject) {

    let eventStore = EKEventStore()

    eventStore.requestAccess( to: EKEntityType.event, completion:{(granted, error) in

        if (granted) && (error == nil) {
            print("granted \(granted)")
            print("error \(error)")

            let event = EKEvent(eventStore: eventStore)

            event.title = "Event Title"
            event.startDate = Date()
            event.endDate = Date()
            event.notes = "Event Details Here"
            event.calendar = eventStore.defaultCalendarForNewEvents

            var event_id = ""
            do {
                try eventStore.save(event, span: .thisEvent)
                event_id = event.eventIdentifier
            }
            catch let error as NSError {
                print("json error: \(error.localizedDescription)")
            }

            if(event_id != ""){
                print("event added !")
            }
        }
    })
}

Spring's overriding bean

Question was more about XML but as annotation are more popular nowadays and it works similarly I'll show by example. Let's create class Foo:

public class Foo {
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

and two Configuration files (you can't create one):

@Configuration
public class Configuration1 {
    @Bean
    public Foo foo() {
        Foo foo = new Foo();
        foo.setName("configuration1");
        return foo;
    }
}

and

@Configuration
public class Configuration2 {
    @Bean
    public Foo foo() {
        Foo foo = new Foo();
        foo.setName("configuration2");
        return foo;
    }
}

and let's see what happens when calling foo.getName():

@SpringBootApplication
public class OverridingBeanDefinitionsApplication {

    public static void main(String[] args) {
        SpringApplication.run(OverridingBeanDefinitionsApplication.class, args);

        AnnotationConfigApplicationContext applicationContext =
                new AnnotationConfigApplicationContext(
                        Configuration1.class, Configuration2.class);

        Foo foo = applicationContext.getBean(Foo.class);
        System.out.println(foo.getName());
    }
}

in this example result is: configuration2. The Spring Container gets all configuration metadata sources and merges bean definitions in those sources. In this example there are two @Beans. Order in which they are fed into ApplicationContext decide. You can flip new AnnotationConfigApplicationContext(Configuration2.class, Configuration1.class); and result will be configuration1.

subtract time from date - moment js

There is a simple function subtract which moment library gives us to subtract time from some time. Using it is also very simple.

moment(Date.now()).subtract(7, 'days'); // This will subtract 7 days from current time
moment(Date.now()).subtract(3, 'd'); // This will subtract 3 days from current time

//You can do this for days, years, months, hours, minutes, seconds
//You can also subtract multiple things simulatneously

//You can chain it like this.
moment(Date.now()).subtract(3, 'd').subtract(5. 'h'); // This will subtract 3 days and 5 hours from current time

//You can also use it as object literal
moment(Date.now()).subtract({days:3, hours:5}); // This will subtract 3 days and 5 hours from current time

Hope this helps!

Why does intellisense and code suggestion stop working when Visual Studio is open?

If anyone is still having this issue, simply close the solution and then reopen it.

Save a list to a .txt file

You can use inbuilt library pickle

This library allows you to save any object in python to a file

This library will maintain the format as well

import pickle
with open('/content/list_1.txt', 'wb') as fp:
    pickle.dump(list_1, fp)

you can also read the list back as an object using same library

with open ('/content/list_1.txt', 'rb') as fp:
    list_1 = pickle.load(fp)

reference : Writing a list to a file with Python

How to catch an Exception from a thread

Most likely;

  • you don't need to pass the exception from one thread to another.
  • if you want to handle an exception, just do it in the thread which threw it.
  • your main thread doesn't need to wait from the background thread in this example, which actually means you don't need a background thread at all.

However, lets assume you do need to handle an exception from a child thread another. I would use an ExecutorService like this:

ExecutorService executor = Executors.newSingleThreadExecutor();
Future<Void> future = executor.submit(new Callable<Void>() {
    @Override
    public Void call() throws Exception {
        System.out.println("** Started");
        Thread.sleep(2000);
        throw new IllegalStateException("exception from thread");
    }
});
try {
    future.get(); // raises ExecutionException for any uncaught exception in child
} catch (ExecutionException e) {
    System.out.println("** RuntimeException from thread ");
    e.getCause().printStackTrace(System.out);
}
executor.shutdown();
System.out.println("** Main stopped");

prints

** Started
** RuntimeException from thread 
java.lang.IllegalStateException: exception from thread
    at Main$1.call(Main.java:11)
    at Main$1.call(Main.java:6)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)
** Main stopped

Difference between /res and /assets directories

Ted Hopp answered this quite nicely. I have been using res/raw for my opengl texture and shader files. I was thinking about moving them to an assets directory to provide a hierarchical organization.

This thread convinced me not to. First, because I like the use of a unique resource id. Second because it's very simple to use InputStream/openRawResource or BitmapFactory to read in the file. Third because it's very useful to be able to use in a portable library.

What does 'const static' mean in C and C++?

That line of code can actually appear in several different contexts and alghough it behaves approximately the same, there are small differences.

Namespace Scope

// foo.h
static const int i = 0;

'i' will be visible in every translation unit that includes the header. However, unless you actually use the address of the object (for example. '&i'), I'm pretty sure that the compiler will treat 'i' simply as a type safe 0. Where two more more translation units take the '&i' then the address will be different for each translation unit.

// foo.cc
static const int i = 0;

'i' has internal linkage, and so cannot be referred to from outside of this translation unit. However, again unless you use its address it will most likely be treated as a type-safe 0.

One thing worth pointing out, is that the following declaration:

const int i1 = 0;

is exactly the same as static const int i = 0. A variable in a namespace declared with const and not explicitly declared with extern is implicitly static. If you think about this, it was the intention of the C++ committee to allow const variables to be declared in header files without always needing the static keyword to avoid breaking the ODR.

Class Scope

class A {
public:
  static const int i = 0;
};

In the above example, the standard explicitly specifies that 'i' does not need to be defined if its address is not required. In other words if you only use 'i' as a type-safe 0 then the compiler will not define it. One difference between the class and namespace versions is that the address of 'i' (if used in two ore more translation units) will be the same for the class member. Where the address is used, you must have a definition for it:

// a.h
class A {
public:
  static const int i = 0;
};

// a.cc
#include "a.h"
const int A::i;            // Definition so that we can take the address

Razor View Engine : An expression tree may not contain a dynamic operation

This error happened to me because I had @@model instead of @model... copy & paste error in my case. Changing to @model fixed it for me.

Android: remove left margin from actionbar's custom layout

Instead of adding a toolbar in the layout, you can set your custom view as shown below.

Toolbar parent = (Toolbar) customView.getParent();
parent.setContentInsetsAbsolute(0,0);

TypeError: worker() takes 0 positional arguments but 1 was given

class KeyStatisticCollection(DataDownloadUtilities.DataDownloadCollection):
def GenerateAddressStrings(self):
    pass    
def worker(self):
    pass
def DownloadProc(self):
    pass

Using jquery to delete all elements with a given id

As already said, only one element can have a specific ID. Use classes instead. Here is jQuery-free version to remove the nodes:

var form = document.getElementById('your-form-id');
var spans = form.getElementsByTagName('span');

for(var i = spans.length; i--;) {
    var span = spans[i];
    if(span.className.match(/\btheclass\b/)) {
        span.parentNode.removeChild(span);
    }
}

getElementsByTagName is the most cross-browser-compatible method that can be used here. getElementsByClassName would be much better, but is not supported by Internet Explorer <= IE 8.

Working Demo

How to compile or convert sass / scss to css with node-sass (no Ruby)?

I picked node-sass implementer for libsass because it is based on node.js.

Installing node-sass

  • (Prerequisite) If you don't have npm, install Node.js first.
  • $ npm install -g node-sass installs node-sass globally -g.

This will hopefully install all you need, if not read libsass at the bottom.

How to use node-sass from Command line and npm scripts

General format:

$ node-sass [options] <input.scss> [output.css]
$ cat <input.scss> | node-sass > output.css

Examples:

  1. $ node-sass my-styles.scss my-styles.css compiles a single file manually.
  2. $ node-sass my-sass-folder/ -o my-css-folder/ compiles all the files in a folder manually.
  3. $ node-sass -w sass/ -o css/ compiles all the files in a folder automatically whenever the source file(s) are modified. -w adds a watch for changes to the file(s).

More usefull options like 'compression' @ here. Command line is good for a quick solution, however, you can use task runners like Grunt.js or Gulp.js to automate the build process.

You can also add the above examples to npm scripts. To properly use npm scripts as an alternative to gulp read this comprehensive article @ css-tricks.com especially read about grouping tasks.

  • If there is no package.json file in your project directory running $ npm init will create one. Use it with -y to skip the questions.
  • Add "sass": "node-sass -w sass/ -o css/" to scripts in package.json file. It should look something like this:
"scripts": {
    "test" : "bla bla bla",
    "sass": "node-sass -w sass/ -o css/"
 }
  • $ npm run sass will compile your files.

How to use with gulp

  • $ npm install -g gulp installs Gulp globally.
  • If there is no package.json file in your project directory running $ npm init will create one. Use it with -y to skip the questions.
  • $ npm install --save-dev gulp installs Gulp locally. --save-dev adds gulp to devDependencies in package.json.
  • $ npm install gulp-sass --save-dev installs gulp-sass locally.
  • Setup gulp for your project by creating a gulpfile.js file in your project root folder with this content:
'use strict';
var gulp = require('gulp');

A basic example to transpile

Add this code to your gulpfile.js:

var gulp = require('gulp');
var sass = require('gulp-sass');
gulp.task('sass', function () {
  gulp.src('./sass/**/*.scss')
    .pipe(sass().on('error', sass.logError))
    .pipe(gulp.dest('./css'));
});

$ gulp sass runs the above task which compiles .scss file(s) in the sass folder and generates .css file(s) in the css folder.

To make life easier, let's add a watch so we don't have to compile it manually. Add this code to your gulpfile.js:

gulp.task('sass:watch', function () {
  gulp.watch('./sass/**/*.scss', ['sass']);
});

All is set now! Just run the watch task:

$ gulp sass:watch

How to use with Node.js

As the name of node-sass implies, you can write your own node.js scripts for transpiling. If you are curious, check out node-sass project page.

What about libsass?

Libsass is a library that needs to be built by an implementer such as sassC or in our case node-sass. Node-sass contains a built version of libsass which it uses by default. If the build file doesn't work on your machine, it tries to build libsass for your machine. This process requires Python 2.7.x (3.x doesn't work as of today). In addition:

LibSass requires GCC 4.6+ or Clang/LLVM. If your OS is older, this version may not compile. On Windows, you need MinGW with GCC 4.6+ or VS 2013 Update 4+. It is also possible to build LibSass with Clang/LLVM on Windows.

positional argument follows keyword argument

The grammar of the language specifies that positional arguments appear before keyword or starred arguments in calls:

argument_list        ::=  positional_arguments ["," starred_and_keywords]
                            ["," keywords_arguments]
                          | starred_and_keywords ["," keywords_arguments]
                          | keywords_arguments

Specifically, a keyword argument looks like this: tag='insider trading!' while a positional argument looks like this: ..., exchange, .... The problem lies in that you appear to have copy/pasted the parameter list, and left some of the default values in place, which makes them look like keyword arguments rather than positional ones. This is fine, except that you then go back to using positional arguments, which is a syntax error.

Also, when an argument has a default value, such as price=None, that means you don't have to provide it. If you don't provide it, it will use the default value instead.

To resolve this error, convert your later positional arguments into keyword arguments, or, if they have default values and you don't need to use them, simply don't specify them at all:

order_id = kite.order_place(self, exchange, tradingsymbol,
    transaction_type, quantity)

# Fully positional:
order_id = kite.order_place(self, exchange, tradingsymbol, transaction_type, quantity, price, product, order_type, validity, disclosed_quantity, trigger_price, squareoff_value, stoploss_value, trailing_stoploss, variety, tag)

# Some positional, some keyword (all keywords at end):

order_id = kite.order_place(self, exchange, tradingsymbol,
    transaction_type, quantity, tag='insider trading!')

Align image to left of text on same line - Twitter Bootstrap3

Use Nesting column

To nest your content with the default grid, add a new .row and set of .col-sm-* columns within an existing .col-sm-* column. Nested rows should include a set of columns that add up to 12 or fewer (it is not required that you use all 12 available columns).

enter image description here

_x000D_
_x000D_
<div class="row">_x000D_
  <div class="col-sm-9">_x000D_
    Level 1: .col-sm-9_x000D_
    <div class="row">_x000D_
      <div class="col-xs-8 col-sm-6">_x000D_
        Level 2: .col-xs-8 .col-sm-6_x000D_
      </div>_x000D_
      <div class="col-xs-4 col-sm-6">_x000D_
        Level 2: .col-xs-4 .col-sm-6_x000D_
      </div>_x000D_
    </div>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

How can I make a UITextField move up when the keyboard is present - on starting to edit?

There are many answers available telling the approach. I took the same approach but the implementation isn't good.

Here is the base Idea . I made modifications to keyboardWasShown method.

{
// Obtain keyboard Info
NSDictionary* info = [notification userInfo];
CGRect keyboardRect = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];
keyboardRect = [self.view convertRect:keyboardRect fromView:nil];

// Obtain ScrollView Info w.r.t. top View
CGRect scrollViewRect = [self.view convertRect:self.scrollView.frame fromView:nil];

// Depending upon your screen Ui, Scroll View's bottom edge might be at some offset from screen's bottom
// Calculate the exact offset
int scrollViewBottomOffset = self.view.frame.size.height - (scrollViewRect.origin.y + scrollViewRect.size.height);
int heightToBeAdjusted = keyboardRect.size.height - scrollViewBottomOffset;


// We may also need to consider the Insets if already present with ScrollView. Let's keep it simple for now
// But we should store these, so that we can restore the Insets when Keyboard is gone
// origInsets = self.scrollView.contentInset;

// Set the new Insets for ScrollView
UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, heightToBeAdjusted, 0.0);
self.scrollView.contentInset = contentInsets;
self.scrollView.scrollIndicatorInsets = contentInsets;

// Visible frame (not overlapped by Keyboard)
CGRect visibleFrame = self.view.frame;
visibleFrame.size.height -= keyboardRect.size.height;

// Get the Rect for Textfield w.r.t self.view
CGRect activeFieldFrame = self.activeField.frame;
activeFieldFrame = [self.view convertRect:activeFieldFrame fromView:self.scrollView];

// Check if the TextField is Visible or not
if (!CGRectContainsRect(visibleFrame, activeFieldFrame) ) {
    // Scroll to make it visible but for scrolling use the activeField frame w.r.t. to scroll View
    [self.scrollView scrollRectToVisible:self.activeField.frame animated:YES];
}

}

And add this method to initialize the activeField

- (IBAction)textFieldDidBeginEditing:(UITextField *)sender
{
self.activeField = sender;
}

Detect change to ngModel on a select tag (Angular 2)

I have stumbled across this question and I will submit my answer that I used and worked pretty well. I had a search box that filtered and array of objects and on my search box I used the (ngModelChange)="onChange($event)"

in my .html

<input type="text" [(ngModel)]="searchText" (ngModelChange)="reSearch(newValue)" placeholder="Search">

then in my component.ts

reSearch(newValue: string) {
    //this.searchText would equal the new value
    //handle my filtering with the new value
}

What's the difference between ASCII and Unicode?

ASCII has 128 code positions, allocated to graphic characters and control characters (control codes).

Unicode has 1,114,112 code positions. About 100,000 of them have currently been allocated to characters, and many code points have been made permanently noncharacters (i.e. not used to encode any character ever), and most code points are not yet assigned.

The only things that ASCII and Unicode have in common are: 1) They are character codes. 2) The 128 first code positions of Unicode have been defined to have the same meanings as in ASCII, except that the code positions of ASCII control characters are just defined as denoting control characters, with names corresponding to their ASCII names, but their meanings are not defined in Unicode.

Sometimes, however, Unicode is characterized (even in the Unicode standard!) as “wide ASCII”. This is a slogan that mainly tries to convey the idea that Unicode is meant to be a universal character code the same way as ASCII once was (though the character repertoire of ASCII was hopelessly insufficient for universal use), as opposite to using different codes in different systems and applications and for different languages.

Unicode as such defines only the “logical size” of characters: Each character has a code number in a specific range. These code numbers can be presented using different transfer encodings, and internally, in memory, Unicode characters are usually represented using one or two 16-bit quantities per character, depending on character range, sometimes using one 32-bit quantity per character.

Skip first entry in for loop in python?

for item in do_not_use_list_as_a_name[1:-1]:
    #...do whatever

Determine distance from the top of a div to top of window with javascript

I used this:

                              myElement = document.getElemenById("xyz");
Get_Offset_From_Start       ( myElement );  // returns positions from website's start position
Get_Offset_From_CurrentView ( myElement );  // returns positions from current scrolled view's TOP and LEFT

code:

function Get_Offset_From_Start (object, offset) { 
    offset = offset || {x : 0, y : 0};
    offset.x += object.offsetLeft;       offset.y += object.offsetTop;
    if(object.offsetParent) {
        offset = Get_Offset_From_Start (object.offsetParent, offset);
    }
    return offset;
}

function Get_Offset_From_CurrentView (myElement) {
    if (!myElement) return;
    var offset = Get_Offset_From_Start (myElement);
    var scrolled = GetScrolled (myElement.parentNode);
    var posX = offset.x - scrolled.x;   var posY = offset.y - scrolled.y;
    return {lefttt: posX , toppp: posY };
}
//helper
function GetScrolled (object, scrolled) {
    scrolled = scrolled || {x : 0, y : 0};
    scrolled.x += object.scrollLeft;    scrolled.y += object.scrollTop;
    if (object.tagName.toLowerCase () != "html" && object.parentNode) { scrolled=GetScrolled (object.parentNode, scrolled); }
    return scrolled;
}

    /*
    // live monitoring
    window.addEventListener('scroll', function (evt) {
        var Positionsss =  Get_Offset_From_CurrentView(myElement);  
        console.log(Positionsss);
    });
    */

How to efficiently count the number of keys/properties of an object in JavaScript?

You could use this code:

if (!Object.keys) {
    Object.keys = function (obj) {
        var keys = [],
            k;
        for (k in obj) {
            if (Object.prototype.hasOwnProperty.call(obj, k)) {
                keys.push(k);
            }
        }
        return keys;
    };
}

Then you can use this in older browsers as well:

var len = Object.keys(obj).length;

Circle line-segment collision detection algorithm?

I have created this function for iOS following the answer given by chmike

+ (NSArray *)intersectionPointsOfCircleWithCenter:(CGPoint)center withRadius:(float)radius toLinePoint1:(CGPoint)p1 andLinePoint2:(CGPoint)p2
{
    NSMutableArray *intersectionPoints = [NSMutableArray array];

    float Ax = p1.x;
    float Ay = p1.y;
    float Bx = p2.x;
    float By = p2.y;
    float Cx = center.x;
    float Cy = center.y;
    float R = radius;


    // compute the euclidean distance between A and B
    float LAB = sqrt( pow(Bx-Ax, 2)+pow(By-Ay, 2) );

    // compute the direction vector D from A to B
    float Dx = (Bx-Ax)/LAB;
    float Dy = (By-Ay)/LAB;

    // Now the line equation is x = Dx*t + Ax, y = Dy*t + Ay with 0 <= t <= 1.

    // compute the value t of the closest point to the circle center (Cx, Cy)
    float t = Dx*(Cx-Ax) + Dy*(Cy-Ay);

    // This is the projection of C on the line from A to B.

    // compute the coordinates of the point E on line and closest to C
    float Ex = t*Dx+Ax;
    float Ey = t*Dy+Ay;

    // compute the euclidean distance from E to C
    float LEC = sqrt( pow(Ex-Cx, 2)+ pow(Ey-Cy, 2) );

    // test if the line intersects the circle
    if( LEC < R )
    {
        // compute distance from t to circle intersection point
        float dt = sqrt( pow(R, 2) - pow(LEC,2) );

        // compute first intersection point
        float Fx = (t-dt)*Dx + Ax;
        float Fy = (t-dt)*Dy + Ay;

        // compute second intersection point
        float Gx = (t+dt)*Dx + Ax;
        float Gy = (t+dt)*Dy + Ay;

        [intersectionPoints addObject:[NSValue valueWithCGPoint:CGPointMake(Fx, Fy)]];
        [intersectionPoints addObject:[NSValue valueWithCGPoint:CGPointMake(Gx, Gy)]];
    }

    // else test if the line is tangent to circle
    else if( LEC == R ) {
        // tangent point to circle is E
        [intersectionPoints addObject:[NSValue valueWithCGPoint:CGPointMake(Ex, Ey)]];
    }
    else {
        // line doesn't touch circle
    }

    return intersectionPoints;
}

Disable ONLY_FULL_GROUP_BY

On:

  • Ubuntu 14.04
  • mysql Ver 14.14 Distrib 5.7.16, for Linux (x86_64) using EditLine wrapper

Do:

$ sudo nano /etc/mysql/conf.d/mysql.cnf

Copy and paste:

[mysqld]
sql_mode=STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION

To the bottom of the file

$ sudo service mysql restart

C function that counts lines in file

You declare

int countlines(char *filename)

to take a char * argument.

You call it like this

countlines(fp)

passing in a FILE *.

That is why you get that compile error.

You probably should change that second line to

countlines("Test.txt")

since you open the file in countlines

Your current code is attempting to open the file in two different places.

PHP Fatal error: Using $this when not in object context

Just use the Class method using this foobar->foobarfunc();

how to convert from int to char*?

C-style solution could be to use itoa, but better way is to print this number into string by using sprintf / snprintf. Check this question: How to convert an integer to a string portably?

Note that itoa function is not defined in ANSI-C and is not part of C++, but is supported by some compilers. It's a non-standard function, thus you should avoid using it. Check this question too: Alternative to itoa() for converting integer to string C++?

Also note that writing C-style code while programming in C++ is considered bad practice and sometimes referred as "ghastly style". Do you really want to convert it into C-style char* string? :)

Best way to encode text data for XML

XmlTextWriter.WriteString() does the escaping.

Convert float64 column to int64 in Pandas

You can need to pass in the string 'int64':

>>> import pandas as pd
>>> df = pd.DataFrame({'a': [1.0, 2.0]})  # some test dataframe

>>> df['a'].astype('int64')
0    1
1    2
Name: a, dtype: int64

There are some alternative ways to specify 64-bit integers:

>>> df['a'].astype('i8')      # integer with 8 bytes (64 bit)
0    1
1    2
Name: a, dtype: int64

>>> import numpy as np
>>> df['a'].astype(np.int64)  # native numpy 64 bit integer
0    1
1    2
Name: a, dtype: int64

Or use np.int64 directly on your column (but it returns a numpy.array):

>>> np.int64(df['a'])
array([1, 2], dtype=int64)

how to sort order of LEFT JOIN in SQL query?

Try using MAX with a GROUP BY.

SELECT u.userName, MAX(c.carPrice)
FROM users u
    LEFT JOIN cars c ON u.id = c.belongsToUser
WHERE u.id = 4;
GROUP BY u.userName;

Further information on GROUP BY

The group by clause is used to split the selected records into groups based on unique combinations of the group by columns. This then allows us to use aggregate functions (eg. MAX, MIN, SUM, AVG, ...) that will be applied to each group of records in turn. The database will return a single result record for each grouping.

For example, if we have a set of records representing temperatures over time and location in a table like this:

Location   Time    Temperature
--------   ----    -----------
London     12:00          10.0
Bristol    12:00          12.0
Glasgow    12:00           5.0
London     13:00          14.0
Bristol    13:00          13.0
Glasgow    13:00           7.0
...

Then if we want to find the maximum temperature by location, then we need to split the temperature records into groupings, where each record in a particular group has the same location. We then want to find the maximum temperature of each group. The query to do this would be as follows:

SELECT Location, MAX(Temperature)
FROM Temperatures
GROUP BY Location;

Shrink to fit content in flexbox, or flex-basis: content workaround?

I want columns One and Two to shrink/grow to fit rather than being fixed.

Have you tried: flex-basis: auto

or this:

flex: 1 1 auto, which is short for:

  • flex-grow: 1 (grow proportionally)
  • flex-shrink: 1 (shrink proportionally)
  • flex-basis: auto (initial size based on content size)

or this:

main > section:first-child {
    flex: 1 1 auto;
    overflow-y: auto;
}

main > section:nth-child(2) {
    flex: 1 1 auto;
    overflow-y: auto;
}

main > section:last-child {
    flex: 20 1 auto;
    display: flex;
    flex-direction: column;  
}

revised demo

Related:

setting min date in jquery datepicker

basically if you already specify the year range there is no need to use mindate and maxdate if only year is required

How to center absolute div horizontally using CSS?

so easy, only use margin and left, right properties:

.elements {
 position: absolute;
 margin-left: auto;
 margin-right: auto;
 left: 0;
 right: 0;
}

You can see more in this tip => How to set div element to center in html- Obinb blog

Which is the default location for keystore/truststore of Java applications?

In Java, according to the JSSE Reference Guide, there is no default for the keystore, the default for the truststore is "jssecacerts, if it exists. Otherwise, cacerts".

A few applications use ~/.keystore as a default keystore, but this is not without problems (mainly because you might not want all the application run by the user to use that trust store).

I'd suggest using application-specific values that you bundle with your application instead, it would tend to be more applicable in general.

How to run a .awk file?

The file you give is a shell script, not an awk program. So, try sh my.awk.

If you want to use awk -f my.awk life.csv > life_out.cs, then remove awk -F , ' and the last line from the file and add FS="," in BEGIN.

Is there a float input type in HTML5?

I just had the same problem, and I could fix it by just putting a comma and not a period/full stop in the number because of French localization.

So it works with:

2 is OK

2,5 is OK

2.5 is KO (The number is considered "illegal" and you receive empty value).

Google Text-To-Speech API

Google text to speech

<!DOCTYPE html>
<html>
    <head>
        <script>
            function play(id){
            var text = document.getElementById(id).value;
            var url = 'http://translate.google.com/translate_tts?tl=en&q='+text;
            var a = new Audio(url);
                a.play();
            }
        </script>
    </head>
    <body>
        <input type="text" id="text" />
        <button onclick="play('text');"> Speak it </button>
    </body>
</html>

Get css top value as number not as string?

You can use the parseInt() function to convert the string to a number, e.g:

parseInt($('#elem').css('top'));

Update: (as suggested by Ben): You should give the radix too:

parseInt($('#elem').css('top'), 10);

Forces it to be parsed as a decimal number, otherwise strings beginning with '0' might be parsed as an octal number (might depend on the browser used).

What are file descriptors, explained in simple terms?

Other answers added great stuff. I will add just my 2 cents.

According to Wikipedia we know for sure: a file descriptor is a non-negative integer. The most important thing I think is missing, would be to say:

File descriptors are bound to a process ID.

We know most famous file descriptors are 0, 1 and 2. 0 corresponds to STDIN, 1 to STDOUT, and 2 to STDERR.

Say, take shell processes as an example and how does it apply for it?

Check out this code

#>sleep 1000 &
[12] 14726

We created a process with the id 14726 (PID). Using the lsof -p 14726 we can get the things like this:

COMMAND   PID USER   FD   TYPE DEVICE SIZE/OFF    NODE NAME
sleep   14726 root  cwd    DIR    8,1     4096 1201140 /home/x
sleep   14726 root  rtd    DIR    8,1     4096       2 /
sleep   14726 root  txt    REG    8,1    35000  786587 /bin/sleep
sleep   14726 root  mem    REG    8,1 11864720 1186503 /usr/lib/locale/locale-archive
sleep   14726 root  mem    REG    8,1  2030544  137184 /lib/x86_64-linux-gnu/libc-2.27.so
sleep   14726 root  mem    REG    8,1   170960  137156 /lib/x86_64-linux-gnu/ld-2.27.so
sleep   14726 root    0u   CHR  136,6      0t0       9 /dev/pts/6
sleep   14726 root    1u   CHR  136,6      0t0       9 /dev/pts/6
sleep   14726 root    2u   CHR  136,6      0t0       9 /dev/pts/6

The 4-th column FD and the very next column TYPE correspond to the File Descriptor and the File Descriptor type.

Some of the values for the FD can be:

cwd – Current Working Directory
txt – Text file
mem – Memory mapped file
mmap – Memory mapped device

But the real file descriptor is under:

NUMBER – Represent the actual file descriptor. 

The character after the number i.e "1u", represents the mode in which the file is opened. r for read, w for write, u for read and write.

TYPE specifies the type of the file. Some of the values of TYPEs are:

REG – Regular File
DIR – Directory
FIFO – First In First Out

But all file descriptors are CHR – Character special file (or character device file)

Now, we can identify the File Descriptors for STDIN, STDOUT and STDERR easy with lsof -p PID, or we can see the same if we ls /proc/PID/fd.

Note also that file descriptor table that kernel keeps track of is not the same as files table or inodes table. These are separate, as some other answers explained.

fd table

You may ask yourself where are these file descriptors physically and what is stored in /dev/pts/6 for instance

sleep   14726 root    0u   CHR  136,6      0t0       9 /dev/pts/6
sleep   14726 root    1u   CHR  136,6      0t0       9 /dev/pts/6
sleep   14726 root    2u   CHR  136,6      0t0       9 /dev/pts/6

Well, /dev/pts/6 lives purely in memory. These are not regular files, but so called character device files. You can check this with: ls -l /dev/pts/6 and they will start with c, in my case crw--w----.

Just to recall most Linux like OS define seven types of files:

  • Regular files
  • Directories
  • Character device files
  • Block device files
  • Local domain sockets
  • Named pipes (FIFOs) and
  • Symbolic links

How can I specify a local gem in my Gemfile?

In order to use local gem repository in a Rails project, follow the steps below:

  1. Check if your gem folder is a git repository (the command is executed in the gem folder)

    git rev-parse --is-inside-work-tree
    
  2. Getting repository path (the command is executed in the gem folder)

    git rev-parse --show-toplevel
    
  3. Setting up a local override for the rails application

    bundle config local.GEM_NAME /path/to/local/git/repository
    

    where GEM_NAME is the name of your gem and /path/to/local/git/repository is the output of the command in point 2

  4. In your application Gemfile add the following line:

    gem 'GEM_NAME', :github => 'GEM_NAME/GEM_NAME', :branch => 'master'
    
  5. Running bundle install should give something like this:

    Using GEM_NAME (0.0.1) from git://github.com/GEM_NAME/GEM_NAME.git (at /path/to/local/git/repository) 
    

    where GEM_NAME is the name of your gem and /path/to/local/git/repository from point 2

  6. Finally, run bundle list, not gem list and you should see something like this:

    GEM_NAME (0.0.1 5a68b88)
    

    where GEM_NAME is the name of your gem


A few important cases I am observing using:

Rails 4.0.2  
ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-linux] 
Ubuntu 13.10  
RubyMine 6.0.3
  • It seems RubyMine is not showing local gems as an external library. More information about the bug can be found here and here
  • When I am changing something in the local gem, in order to be loaded in the rails application I should stop/start the rails server
  • If I am changing the version of the gem, stopping/starting the Rails server gives me an error. In order to fix it, I am specifying the gem version in the rails application Gemfile like this:

    gem 'GEM_NAME', '0.0.2', :github => 'GEM_NAME/GEM_NAME', :branch => 'master'
    

What is the difference between Visual Studio Express 2013 for Windows and Visual Studio Express 2013 for Windows Desktop?

Visual Studio for Windows Apps is meant to be used to build Windows Store Apps using HTML & Javascript or WinRT and XAML. These can also run on the Windows tablet that run Windows RT.

Visual Studio for Windows Desktop is meant to build applications using Windows Forms or Windows Presentation Foundation, these can run on Windows 8.1 on a normal desktop or on a tablet device like the Surface Pro in desktop mode (like a classic windows application).

In Java, how do I convert a byte array to a string of hex digits while keeping leading zeros?

String result = String.format("%0" + messageDigest.length + "s", hexString.toString())

That's the shortest solution given what you already have. If you could convert the byte array to a numeric value, String.format can convert it to a hex string at the same time.

Can't accept license agreement Android SDK Platform 24

This will update your android SDK and accept the license in the same time (ex for Android 25):

android update sdk --no-ui --filter build-tools-25.0.0,android-25,extra-android-m2repository

Adding header to all request with Retrofit 2

In my case addInterceptor()didn't work to add HTTP headers to my request, I had to use addNetworkInterceptor(). Code is as follows:

OkHttpClient.Builder httpClient = new OkHttpClient.Builder();
httpClient.addNetworkInterceptor(new AddHeaderInterceptor());

And the interceptor code:

public class AddHeaderInterceptor implements Interceptor {
    @Override
    public Response intercept(Chain chain) throws IOException {

        Request.Builder builder = chain.request().newBuilder();
        builder.addHeader("Authorization", "MyauthHeaderContent");

        return chain.proceed(builder.build());
    }
}

This and more examples on this gist

How to create a XML object from String in Java?

If you can create a string xml you can easily transform it to the xml document object e.g. -

String xmlString = "<?xml version=\"1.0\" encoding=\"utf-8\"?><a><b></b><c></c></a>";  

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();  
DocumentBuilder builder;  
try {  
    builder = factory.newDocumentBuilder();  
    Document document = builder.parse(new InputSource(new StringReader(xmlString)));  
} catch (Exception e) {  
    e.printStackTrace();  
} 

You can use the document object and xml parsing libraries or xpath to get back the ip address.

Conda activate not working?

For windows, Use the Anaconda Powershell Prompt

enter image description here

How do you redirect to a page using the POST verb?

try this one

return Content("<form action='actionname' id='frmTest' method='post'><input type='hidden' name='someValue' value='" + someValue + "' /><input type='hidden' name='anotherValue' value='" + anotherValue + "' /></form><script>document.getElementById('frmTest').submit();</script>");

How to center HTML5 Videos?

I was having the same problem. This worked for me:

.center {
    margin: 0 auto; 
    width: 400px;
    **display:block**
 }

I have Python on my Ubuntu system, but gcc can't find Python.h

On Ubuntu, you would need to install a package called python-dev. Since this package doesn't seem to be installed (locate Python.h didn't find anything) and you can't install it system-wide yourself, we need a different solution.

You can install Python in your home directory -- you don't need any special permissions to do this. If you are allowed to use a web browser and run a gcc, this should work for you. To this end

  1. Download the source tarball.

  2. Unzip with

    tar xjf Python-2.7.2.tar.bz2
    
  3. Build and install with

    cd Python-2.7.2
    ./configure --prefix=/home/username/python --enable-unicode=ucs4
    make
    make install
    

Now, you have a complete Python installation in your home directory. Pass -I /home/username/python/include to gcc when compiling to make it aware of Python.h. Pass -L /home/username/python/lib and -lpython2.7 when linking.

"Use of undeclared type" in Swift, even though type is internal, and exists in same module

This might help someone.

I've created new test project with Core Data called "CoreData". Shortly I've got "Use of undeclared type" for NSManagedObjectContext and other Core Data classes. After several attempts of importing, adding to Build phases, etc. I've deleted project and started new one called "TestingCoreData" and it all worked well.

Don't name (test) Projects like name of the Classes

MS Access: how to compact current database in VBA

I did this many years back on 2003 or possibly 97, yikes!

If I recall you need to use one of the subcommands above tied to a timer. You cannot operate on the db with any connections or forms open.

So you do something about closing all forms, and kick off the timer as the last running method. (which will in turn call the compact operation once everything closes)

If you haven't figured this out I could dig through my archives and pull it up.

How do I get java logging output to appear on a single line?

if you're using java.util.logging, then there is a configuration file that is doing this to log contents (unless you're using programmatic configuration). So, your options are
1) run post -processor that removes the line breaks
2) change the log configuration AND remove the line breaks from it. Restart your application (server) and you should be good.

PYODBC--Data source name not found and no default driver specified

Have you installed any product of SQL in your system machine ? You can download and install "ODBC Driver 13(or any version) for SQL Server" and try to run if you havent alerady done.

Switch role after connecting to database

--create a user that you want to use the database as:

create role neil;

--create the user for the web server to connect as:

create role webgui noinherit login password 's3cr3t';

--let webgui set role to neil:

grant neil to webgui; --this looks backwards but is correct.

webgui is now in the neil group, so webgui can call set role neil . However, webgui did not inherit neil's permissions.

Later, login as webgui:

psql -d some_database -U webgui
(enter s3cr3t as password)

set role neil;

webgui does not need superuser permission for this.

You want to set role at the beginning of a database session and reset it at the end of the session. In a web app, this corresponds to getting a connection from your database connection pool and releasing it, respectively. Here's an example using Tomcat's connection pool and Spring Security:

public class SetRoleJdbcInterceptor extends JdbcInterceptor {

    @Override
    public void reset(ConnectionPool connectionPool, PooledConnection pooledConnection) {

        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();

        if(authentication != null) {
            try {

                /* 
                  use OWASP's ESAPI to encode the username to avoid SQL Injection. Can't use parameters with SET ROLE. Need to write PG codec.

                  Or use a whitelist-map approach
                */
                String username = ESAPI.encoder().encodeForSQL(MY_CODEC, authentication.getName());

                Statement statement = pooledConnection.getConnection().createStatement();
                statement.execute("set role \"" + username + "\"");
                statement.close();
            } catch(SQLException exp){
                throw new RuntimeException(exp);
            }
        }
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {

        if("close".equals(method.getName())){
            Statement statement = ((Connection)proxy).createStatement();
            statement.execute("reset role");
            statement.close();
        }

        return super.invoke(proxy, method, args);
    }
}

Bootstrap 4 Dropdown Menu not working?

It's an issue with popper.js file. What I found at the official site was that bundle files include popper in itself but not jquery. I managed to fix it by adding link to these files:

bootstrap.bundle.js
bootstrap.bundle.min.js

I removed popper.js however since it comes within the bundle file.

Google Chromecast sender error if Chromecast extension is not installed or using incognito

How about filtering these errors ?

With the regex filter bellow, we can dismiss cast_sender.js errors :

^((?!cast_sender).)*$

Do not forget to check Regex box.

enter image description here

Another quick solution is to "Hide network messages".

enter image description here

Flask-SQLalchemy update a row's information

Retrieve an object using the tutorial shown in the Flask-SQLAlchemy documentation. Once you have the entity that you want to change, change the entity itself. Then, db.session.commit().

For example:

admin = User.query.filter_by(username='admin').first()
admin.email = '[email protected]'
db.session.commit()

user = User.query.get(5)
user.name = 'New Name'
db.session.commit()

Flask-SQLAlchemy is based on SQLAlchemy, so be sure to check out the SQLAlchemy Docs as well.

Click event on select option element in chrome

We can achieve this other way despite of directly calling event with <select>.

JS part:

$("#sort").change(function(){

    alert('Selected value: ' + $(this).val());
});

HTML part:

<select id="sort">
    <option value="1">View All</option>
    <option value="2">Ready for Review</option>
    <option value="3">Registration Date</option>
    <option value="4">Last Modified</option>
    <option value="5">Ranking</option>
    <option value="6">Reviewed</option>
</select>

syntaxerror: unexpected character after line continuation character in python

The filename should be a string. In other names it should be within quotes.

f = open("D\\python\\HW\\2_1 - Copy.cp","r")
lines = f.readlines()
for i in lines:
    thisline = i.split(" ");

You can also open the file using with

with open("D\\python\\HW\\2_1 - Copy.cp","r") as f:
    lines = f.readlines()
    for i in lines:
        thisline = i.split(" ");

There is no need to add the semicolon(;) in python. It's ugly.

Hiding a button in Javascript

visibility=hidden

is very useful, but it will still take up space on the page. You can also use

display=none

because that will not only hide the object, but make it so that it doesn't take up space until it is displayed. (Also keep in mind that display's opposite is "block," not "visible")

How to count items in JSON data

import json

json_data = json.dumps({
  "result":[
    {
      "run":[
        {
          "action":"stop"
        },
        {
          "action":"start"
        },
        {
          "action":"start"
        }
      ],
      "find": "true"
    }
  ]
})

item_dict = json.loads(json_data)
print len(item_dict['result'][0]['run'])

Convert it in dict.

Call a function from another file?

First of all you do not need a .py.

If you have a file a.py and inside you have some functions:

def b():
  # Something
  return 1

def c():
  # Something
  return 2

And you want to import them in z.py you have to write

from a import b, c

MVC Razor @foreach

The answer will not work when using the overload to indicate the template @Html.DisplayFor(x => x.Foos, "YourTemplateName) .

Seems to be designed that way, see this case. Also the exception the framework gives (about the type not been as expected) is quite misleading and fooled me on the first try (thanks @CodeCaster)

In this case you have to use @foreach

@foreach (var item in Model.Foos)
{
    @Html.DisplayFor(x => item, "FooTemplate")
}

How to properly use jsPDF library

You only need this link jspdf.min.js

It has everything in it.

<script src="https://cdnjs.cloudflare.com/ajax/libs/jspdf/1.3.2/jspdf.min.js"></script>

'System.Net.Http.HttpContent' does not contain a definition for 'ReadAsAsync' and no extension method

USE This Assembly Referance in your Project

Add a reference to System.Net.Http.Formatting.dll

Get single row result with Doctrine NativeQuery

To fetch single row

$result = $this->getEntityManager()->getConnection()->fetchAssoc($sql)

To fetch all records

$result = $this->getEntityManager()->getConnection()->fetchAll($sql)

Here you can use sql native query, all will work without any issue.

Login to Microsoft SQL Server Error: 18456

I have faced the same issue. You need to enable the Mixed Mode Authentication first. For more details How to enable Mixed Mode Authentication

How to fix the datetime2 out-of-range conversion error using DbContext and SetInitializer?

You can make the field nullable, if that suits your specific modeling concerns. A null date won't be coerced to a date that isn't within the range of the SQL DateTime type the way a default value would. Another option is to explicitly map to a different type, perhaps with,

.HasColumnType("datetime2")

Facebook Graph API, how to get users email?

To get the user email, you have to log in the user with his Facebook account using the email permission. Use for that the Facebook PHP SDK (see on github) as following.

First check if the user is already logged in :

require "facebook.php";
$facebook = new Facebook(array(
    'appId'  => YOUR_APP_ID,
    'secret' => YOUR_APP_SECRET,
));

$user = $facebook->getUser();
if ($user) {
    try {
        $user_profile = $facebook->api('/me');
    } catch (FacebookApiException $e) {
        $user = null;
    }
}

If he his not, you can display the login link asking for the email permission :

if (!$user) {
    $args = array('scope' => 'email');
    echo '<a href="' . $facebook->getLoginUrl() . '">Login with Facebook</a>';
} else {
    echo '<a href="' . $facebook->getLogoutUrl() . '">Logout</a>';
}

When he is logged in the email can be found in the $user_profile array.

Hope that helps !

Search for all occurrences of a string in a mysql database

SQLyog is GUI based solution to the problem of data search across all columns, tables and databases. One can customize search restricting it to field, table and databases.

In its Data Search feature one can search for strings just like one uses Google.

SQLyog Datasearch screenshot

When to use RSpec let()?

I have completely replaced all uses of instance variables in my rspec tests to use let(). I've written a quickie example for a friend who used it to teach a small Rspec class: http://ruby-lambda.blogspot.com/2011/02/agile-rspec-with-let.html

As some of the other answers here says, let() is lazy evaluated so it will only load the ones that require loading. It DRYs up the spec and make it more readable. I've in fact ported the Rspec let() code to use in my controllers, in the style of inherited_resource gem. http://ruby-lambda.blogspot.com/2010/06/stealing-let-from-rspec.html

Along with lazy evaluation, the other advantage is that, combined with ActiveSupport::Concern, and the load-everything-in spec/support/ behavior, you can create your very own spec mini-DSL specific to your application. I've written ones for testing against Rack and RESTful resources.

The strategy I use is Factory-everything (via Machinist+Forgery/Faker). However, it is possible to use it in combination with before(:each) blocks to preload factories for an entire set of example groups, allowing the specs to run faster: http://makandra.com/notes/770-taking-advantage-of-rspec-s-let-in-before-blocks

How to get Exception Error Code in C#

You can use this to check the exception and the inner exception for a Win32Exception derived exception.

catch (Exception e) {  
    var w32ex = e as Win32Exception;
    if(w32ex == null) {
        w32ex = e.InnerException as Win32Exception;
    }    
    if(w32ex != null) {
        int code =  w32ex.ErrorCode;
        // do stuff
    }    
    // do other stuff   
}

Starting with C# 6, when can be used in a catch statement to specify a condition that must be true for the handler for a specific exception to execute.

catch (Win32Exception ex) when (ex.InnerException is Win32Exception) {
    var w32ex = (Win32Exception)ex.InnerException;
    var code =  w32ex.ErrorCode;
}

As in the comments, you really need to see what exception is actually being thrown to understand what you can do, and in which case a specific catch is preferred over just catching Exception. Something like:

  catch (BlahBlahException ex) {  
      // do stuff   
  }

Also System.Exception has a HRESULT

 catch (Exception ex) {  
     var code = ex.HResult;
 }

However, it's only available from .NET 4.5 upwards.

How to apply border radius in IE8 and below IE8 browsers?

PIE makes Internet Explorer 6-9 capable of rendering several of the most useful CSS3 decoration features

http://css3pie.com/

................................................................................

not-null property references a null or transient value

Check the unsaved values for your primary key/Object ID in your hbm files. If you have automated ID creation by hibernate framework and you are setting the ID somewhere it will throw this error.By default the unsaved value is 0, so if you set the ID to 0 you will see this error.

Parse v. TryParse

The TryParse method allows you to test whether something is parseable. If you try Parse as in the first instance with an invalid int, you'll get an exception while in the TryParse, it returns a boolean letting you know whether the parse succeeded or not.

As a footnote, passing in null to most TryParse methods will throw an exception.

How to play or open *.mp3 or *.wav sound file in c++ program?

First of all, write the following code:

#include <Mmsystem.h>
#include <mciapi.h>
//these two headers are already included in the <Windows.h> header
#pragma comment(lib, "Winmm.lib")

To open *.mp3:

mciSendString("open \"*.mp3\" type mpegvideo alias mp3", NULL, 0, NULL);

To play *.mp3:

mciSendString("play mp3", NULL, 0, NULL);

To play and wait until the *.mp3 has finished playing:

mciSendString("play mp3 wait", NULL, 0, NULL);

To replay (play again from start) the *.mp3:

mciSendString("play mp3 from 0", NULL, 0, NULL);

To replay and wait until the *.mp3 has finished playing:

mciSendString("play mp3 from 0 wait", NULL, 0, NULL);

To play the *.mp3 and replay it every time it ends like a loop:

mciSendString("play mp3 repeat", NULL, 0, NULL);

If you want to do something when the *.mp3 has finished playing, then you need to RegisterClassEx by the WNDCLASSEX structure, CreateWindowEx and process it's messages with the GetMessage, TranslateMessage and DispatchMessage functions in a while loop and call:

mciSendString("play mp3 notify", NULL, 0, hwnd); //hwnd is an handle to the window returned from CreateWindowEx. If this doesn't work, then replace the hwnd with MAKELONG(hwnd, 0).

In the window procedure, add the case MM_MCINOTIFY: The code in there will be executed when the mp3 has finished playing.

But if you program a Console Application and you don't deal with windows, then you can CreateThread in suspend state by specifying the CREATE_SUSPENDED flag in the dwCreationFlags parameter and keep the return value in a static variable and call it whatever you want. For instance, I call it mp3. The type of this static variable is HANDLE of course.

Here is the ThreadProc for the lpStartAddress of this thread:

DWORD WINAPI MP3Proc(_In_ LPVOID lpParameter) //lpParameter can be a pointer to a structure that store data that you cannot access outside of this function. You can prepare this structure before `CreateThread` and give it's address in the `lpParameter`
{
    Data *data = (Data*)lpParameter; //If you call this structure Data, but you can call it whatever you want.
    while (true)
    {
        mciSendString("play mp3 from 0 wait", NULL, 0, NULL);
        //Do here what you want to do when the mp3 playback is over
        SuspendThread(GetCurrentThread()); //or the handle of this thread that you keep in a static variable instead
    }
}

All what you have to do now is to ResumeThread(mp3); every time you want to replay your mp3 and something will happen every time it finishes.

You can #define play_my_mp3 ResumeThread(mp3); to make your code more readable.

Of course you can remove the while (true), SuspendThread and the from 0 codes, if you want to play your mp3 file only once and do whatever you want when it is over.

If you only remove the SuspendThread call, then the sound will play over and over again and do something whenever it is over. This is equivalent to:

mciSendString("play mp3 repeat notify", NULL, 0, hwnd); //or MAKELONG(hwnd, 0) instead

in windows.

To pause the *.mp3 in middle:

mciSendString("pause mp3", NULL, 0, NULL);

and to resume it:

mciSendString("resume mp3", NULL, 0, NULL);

To stop it in middle:

mciSendString("stop mp3", NULL, 0, NULL);

Note that you cannot resume a sound that has been stopped, but only paused, but you can replay it by carrying out the play command. When you're done playing this *.mp3, don't forget to:

mciSendString("close mp3", NULL, 0, NULL);

All these actions also apply to (work with) wave files too, but with wave files, you can use "waveaudio" instead of "mpegvideo". Also you can just play them directly without opening them:

PlaySound("*.wav", GetModuleHandle(NULL), SND_FILENAME);

If you don't want to specify an handle to a module:

sndPlaySound("*.wav", SND_FILENAME);

If you don't want to wait until the playback is over:

PlaySound("*.wav", GetModuleHandle(NULL), SND_FILENAME | SND_ASYNC);
//or
sndPlaySound("*.wav", SND_FILENAME | SND_ASYNC);

To play the wave file over and over again:

PlaySound("*.wav", GetModuleHandle(NULL), SND_FILENAME | SND_ASYNC | SND_LOOP);
//or
sndPlaySound("*.wav", SND_FILENAME | SND_ASYNC | SND_LOOP);

Note that you must specify both the SND_ASYNC and SND_LOOP flags, because you never going to wait until a sound, that repeats itself countless times, is over!

Also you can fopen the wave file and copy all it's bytes to a buffer (an enormous/huge (very big) array of bytes) with the fread function and then:

PlaySound(buffer, GetModuleHandle(NULL), SND_MEMORY);
//or
PlaySound(buffer, GetModuleHandle(NULL), SND_MEMORY | SND_ASYNC);
//or
PlaySound(buffer, GetModuleHandle(NULL), SND_MEMORY | SND_ASYNC | SND_LOOP);
//or
sndPlaySound(buffer, SND_MEMORY);
//or
sndPlaySound(buffer, SND_MEMORY | SND_ASYNC);
//or
sndPlaySound(buffer, SND_MEMORY | SND_ASYNC | SND_LOOP);

Either OpenFile or CreateFile or CreateFile2 and either ReadFile or ReadFileEx functions can be used instead of fopen and fread functions.

Hope this fully answers perfectly your question.

What are type hints in Python 3.5?

Adding to Jim's elaborate answer:

Check the typing module -- this module supports type hints as specified by PEP 484.

For example, the function below takes and returns values of type str and is annotated as follows:

def greeting(name: str) -> str:
    return 'Hello ' + name

The typing module also supports:

  1. Type aliasing.
  2. Type hinting for callback functions.
  3. Generics - Abstract base classes have been extended to support subscription to denote expected types for container elements.
  4. User-defined generic types - A user-defined class can be defined as a generic class.
  5. Any type - Every type is a subtype of Any.

ERROR:'keytool' is not recognized as an internal or external command, operable program or batch file

Make sure JAVA_HOME is set and the path in environment variables reflects the bin directory of JAVA_HOME. Basically, the PATH should be able to find the keytools.exe file in your jdk location.

Adding a css class to select using @Html.DropDownList()

Try below code:

@Html.DropDownList("ProductTypeID",null,"",new { @class = "form-control"})

How to view query error in PDO PHP

a quick way to see your errors whilst testing:

$error= $st->errorInfo();
echo $error[2];

How to process POST data in Node.js?

1) Install 'body-parser' from npm.

2) Then in your app.ts

var bodyParser = require('body-parser');

3) then you need to write

app.use(bodyParser.json())

in app.ts module

4) keep in mind that you include

app.use(bodyParser.json())

in the top or before any module declaration.

Ex:

app.use(bodyParser.json())
app.use('/user',user);

5) Then use

var postdata = req.body;

When and Why to use abstract classes/methods?

I know basic use of abstract classes is to create templates for future classes. But are there any more uses of them?

Not only can you define a template for children, but Abstract Classes offer the added benefit of letting you define functionality that your child classes can utilize later.

You could not provide a default method implementation in an Interface prior to Java 8.

When should you prefer them over interfaces and when not?

Abstract Classes are a good fit if you want to provide implementation details to your children but don't want to allow an instance of your class to be directly instantiated (which allows you to partially define a class).

If you want to simply define a contract for Objects to follow, then use an Interface.

Also when are abstract methods useful?

Abstract methods are useful in the same way that defining methods in an Interface is useful. It's a way for the designer of the Abstract class to say "any child of mine MUST implement this method".

How to use onResume()?

After an activity started, restarted (onRestart() happens before onStart()), or paused (onPause()), onResume() called. When the activity is in the state of onResume(), the activity is ready to be used by the app user.

I have studied the activity lifecycle a little bit, and here's my understanding of this topic: If you want to restart the activity (A) at the end of the execution of another, there could be a few different cases.

  1. The other activity (B) has been paused and/or stopped or destroyed, and the activity A possibly had been paused (onPause()), in this case, activity A will call onResume()

  2. The activity B has been paused and/or stopped or destroyed, the activity A possibly had been stopped (onStop()) due to memory thing, in this case, activity A will call onRestart() first, onStart() second, then onResume()

  3. The activity B has been paused and/or stopped or destroyed, the activity A has been destroyed, the programmer can call onStart() manually to start the activity first, then onResume() because when an activity is in the destroyed status the activity has not started, and this happens before the activity being completely removed. If the activity is removed, the activity needs to be created again. Manually calling onStart() I think it's because if the activity not started and it is created, onStart() will be called after onCreate().

If you want to update data, make a data update function and put the function inside the onResume(). Or put a loadData function inside onResume()

It's better to understand the lifecycle with the help of the Activity lifecycle diagram.

Is it possible in Java to catch two exceptions in the same catch block?

Before the launch of Java SE 7 we were habitual of writing code with multiple catch statements associated with a try block. A very basic Example:

 try {
  // some instructions
} catch(ATypeException e) {
} catch(BTypeException e) {
} catch(CTypeException e) {
}

But now with the latest update on Java, instead of writing multiple catch statements we can handle multiple exceptions within a single catch clause. Here is an example showing how this feature can be achieved.

try {
// some instructions
} catch(ATypeException|BTypeException|CTypeException ex) {
   throw e;
}

So multiple Exceptions in a single catch clause not only simplifies the code but also reduce the redundancy of code. I found this article which explains this feature very well along with its implementation. Improved and Better Exception Handling from Java 7 This may help you too.

Android AudioRecord example

Here I am posting you the some code example which record good quality of sound using AudioRecord API.

Note: If you use in emulator the sound quality will not much good because we are using sample rate 8k which only supports in emulator. In device use sample rate to 44.1k for better quality.

public class Audio_Record extends Activity {
    private static final int RECORDER_SAMPLERATE = 8000;
    private static final int RECORDER_CHANNELS = AudioFormat.CHANNEL_IN_MONO;
    private static final int RECORDER_AUDIO_ENCODING = AudioFormat.ENCODING_PCM_16BIT;
    private AudioRecord recorder = null;
    private Thread recordingThread = null;
    private boolean isRecording = false;

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

        setButtonHandlers();
        enableButtons(false);

        int bufferSize = AudioRecord.getMinBufferSize(RECORDER_SAMPLERATE,
                RECORDER_CHANNELS, RECORDER_AUDIO_ENCODING); 
    }

    private void setButtonHandlers() {
        ((Button) findViewById(R.id.btnStart)).setOnClickListener(btnClick);
        ((Button) findViewById(R.id.btnStop)).setOnClickListener(btnClick);
    }

    private void enableButton(int id, boolean isEnable) {
        ((Button) findViewById(id)).setEnabled(isEnable);
    }

    private void enableButtons(boolean isRecording) {
        enableButton(R.id.btnStart, !isRecording);
        enableButton(R.id.btnStop, isRecording);
    }

    int BufferElements2Rec = 1024; // want to play 2048 (2K) since 2 bytes we use only 1024
    int BytesPerElement = 2; // 2 bytes in 16bit format

    private void startRecording() {

        recorder = new AudioRecord(MediaRecorder.AudioSource.MIC,
                RECORDER_SAMPLERATE, RECORDER_CHANNELS,
                RECORDER_AUDIO_ENCODING, BufferElements2Rec * BytesPerElement);

        recorder.startRecording();
        isRecording = true;
        recordingThread = new Thread(new Runnable() {
            public void run() {
                writeAudioDataToFile();
            }
        }, "AudioRecorder Thread");
        recordingThread.start();
    }

        //convert short to byte
    private byte[] short2byte(short[] sData) {
        int shortArrsize = sData.length;
        byte[] bytes = new byte[shortArrsize * 2];
        for (int i = 0; i < shortArrsize; i++) {
            bytes[i * 2] = (byte) (sData[i] & 0x00FF);
            bytes[(i * 2) + 1] = (byte) (sData[i] >> 8);
            sData[i] = 0;
        }
        return bytes;

    }

    private void writeAudioDataToFile() {
        // Write the output audio in byte

        String filePath = "/sdcard/voice8K16bitmono.pcm";
        short sData[] = new short[BufferElements2Rec];

        FileOutputStream os = null;
        try {
            os = new FileOutputStream(filePath);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }

        while (isRecording) {
            // gets the voice output from microphone to byte format

            recorder.read(sData, 0, BufferElements2Rec);
            System.out.println("Short writing to file" + sData.toString());
            try {
                // // writes the data to file from buffer
                // // stores the voice buffer
                byte bData[] = short2byte(sData);
                os.write(bData, 0, BufferElements2Rec * BytesPerElement);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        try {
            os.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void stopRecording() {
        // stops the recording activity
        if (null != recorder) {
            isRecording = false;
            recorder.stop();
            recorder.release();
            recorder = null;
            recordingThread = null;
        }
    }

    private View.OnClickListener btnClick = new View.OnClickListener() {
        public void onClick(View v) {
            switch (v.getId()) {
            case R.id.btnStart: {
                enableButtons(true);
                startRecording();
                break;
            }
            case R.id.btnStop: {
                enableButtons(false);
                stopRecording();
                break;
            }
            }
        }
    };

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            finish();
        }
        return super.onKeyDown(keyCode, event);
    }
}

For more detail try this AUDIORECORD BLOG.

Happy Coding !!

Jquery Ajax Loading image

Its a bit late but if you don't want to use a div specifically, I usually do it like this...

var ajax_image = "<img src='/images/Loading.gif' alt='Loading...' />";
$('#ReplaceDiv').html(ajax_image);

ReplaceDiv is the div that the Ajax inserts too. So when it arrives, the image is replaced.

How to start Apache and MySQL automatically when Windows 8 comes up

Apache

  1. Run cmd as administrator
  2. Go to the Apache bin directory, for example, C:\xampp\apache\bin
  3. Run: httpd.exe -k install more information
  4. Restart the computer, or run the service manually (from services.msc)

MySQL

  1. Run cmd as administrator
  2. Go to the MySQL bin directory, for example, C:\xampp\mysql\bin
  3. Run: mysqld.exe --install more information
  4. Restart the computer, or run the service manually (from services.msc)

Why is printing "B" dramatically slower than printing "#"?

Pure speculation is that you're using a terminal that attempts to do word-wrapping rather than character-wrapping, and treats B as a word character but # as a non-word character. So when it reaches the end of a line and searches for a place to break the line, it sees a # almost immediately and happily breaks there; whereas with the B, it has to keep searching for longer, and may have more text to wrap (which may be expensive on some terminals, e.g., outputting backspaces, then outputting spaces to overwrite the letters being wrapped).

But that's pure speculation.

PHPExcel Make first row bold

Use this:

$sheet->getStyle('A1:'.$sheet->getHighestColumn().'1')->getFont()->setBold(true);

How to set 00:00:00 using moment.js

You've not shown how you're creating the string 2016-01-12T23:00:00.000Z, but I assume via .format().

Anyway, .set() is using your local time zone, but the Z in the time string indicates zero time, otherwise known as UTC.

https://en.wikipedia.org/wiki/ISO_8601#Time_zone_designators

So I assume your local timezone is 23 hours from UTC?

saikumar's answer showed how to load the time in as UTC, but the other option is to use a .format() call that outputs using your local timezone, rather than UTC.

http://momentjs.com/docs/#/get-set/
http://momentjs.com/docs/#/displaying/format/

Waiting for HOME ('android.process.acore') to be launched

I increased the virtual device SD card size from 500MB to 2GiB, the problem solved.

Convert an image to grayscale

Bitmap d = new Bitmap(c.Width, c.Height);

for (int i = 0; i < c.Width; i++)
{
    for (int x = 0; x < c.Height; x++)
    {
        Color oc = c.GetPixel(i, x);
        int grayScale = (int)((oc.R * 0.3) + (oc.G * 0.59) + (oc.B * 0.11));
        Color nc = Color.FromArgb(oc.A, grayScale, grayScale, grayScale);
        d.SetPixel(i, x, nc);
    }
}

This way it also keeps the alpha channel.
Enjoy.

c# dictionary How to add multiple values for single key?

Update: check for existence using TryGetValue to do only one lookup in the case where you have the list:

List<int> list;

if (!dictionary.TryGetValue("foo", out list))
{
    list = new List<int>();
    dictionary.Add("foo", list);
}

list.Add(2);


Original: Check for existence and add once, then key into the dictionary to get the list and add to the list as normal:

var dictionary = new Dictionary<string, List<int>>();

if (!dictionary.ContainsKey("foo"))
    dictionary.Add("foo", new List<int>());

dictionary["foo"].Add(42);
dictionary["foo"].AddRange(oneHundredInts);

Or List<string> as in your case.

As an aside, if you know how many items you are going to add to a dynamic collection such as List<T>, favour the constructor that takes the initial list capacity: new List<int>(100);.

This will grab the memory required to satisfy the specified capacity upfront, instead of grabbing small chunks every time it starts to fill up. You can do the same with dictionaries if you know you have 100 keys.

Multiple submit buttons in an HTML form

Sometimes the provided solution by @palotasb is not sufficient. There are use cases where for example a "Filter" submits button is placed above buttons like "Next and Previous". I found a workaround for this: copy the submit button which needs to act as the default submit button in a hidden div and place it inside the form above any other submit button. Technically it will be submitted by a different button when pressing Enter than when clicking on the visible Next button. But since the name and value are the same, there's no difference in the result.

<html>
<head>
    <style>
        div.defaultsubmitbutton {
            display: none;
        }
    </style>
</head>
<body>
    <form action="action" method="get">
        <div class="defaultsubmitbutton">
            <input type="submit" name="next" value="Next">
        </div>
        <p><input type="text" name="filter"><input type="submit" value="Filter"></p>
        <p>Filtered results</p>
        <input type="radio" name="choice" value="1">Filtered result 1
        <input type="radio" name="choice" value="2">Filtered result 2
        <input type="radio" name="choice" value="3">Filtered result 3
        <div>                
            <input type="submit" name="prev" value="Prev">
            <input type="submit" name="next" value="Next">
        </div>
    </form>
</body>
</html>

ORA-28040: No matching authentication protocol exception

While for most cases replacing ojdbc driver jar will be the solution, my case was different.

If you are certain you are using correct ojdbc driver. Double check if you are actually connecting to the database you are thinking you are. In my case jdbc configuration (in Tomcat/conf) was pointing to different database that had different Oracle version.

React-router: How to manually invoke Link?

React Router v5 - React 16.8+ with Hooks (updated 09/23/2020)

If you're leveraging React Hooks, you can take advantage of the useHistory API that comes from React Router v5.

import React, {useCallback} from 'react';
import {useHistory} from 'react-router-dom';

export default function StackOverflowExample() {
  const history = useHistory();
  const handleOnClick = useCallback(() => history.push('/sample'), [history]);

  return (
    <button type="button" onClick={handleOnClick}>
      Go home
    </button>
  );
}

Another way to write the click handler if you don't want to use useCallback

const handleOnClick = () => history.push('/sample');

React Router v4 - Redirect Component

The v4 recommended way is to allow your render method to catch a redirect. Use state or props to determine if the redirect component needs to be shown (which then trigger's a redirect).

import { Redirect } from 'react-router';

// ... your class implementation

handleOnClick = () => {
  // some action...
  // then redirect
  this.setState({redirect: true});
}

render() {
  if (this.state.redirect) {
    return <Redirect push to="/sample" />;
  }

  return <button onClick={this.handleOnClick} type="button">Button</button>;
}

Reference: https://reacttraining.com/react-router/web/api/Redirect

React Router v4 - Reference Router Context

You can also take advantage of Router's context that's exposed to the React component.

static contextTypes = {
  router: PropTypes.shape({
    history: PropTypes.shape({
      push: PropTypes.func.isRequired,
      replace: PropTypes.func.isRequired
    }).isRequired,
    staticContext: PropTypes.object
  }).isRequired
};

handleOnClick = () => {
  this.context.router.push('/sample');
}

This is how <Redirect /> works under the hood.

Reference: https://github.com/ReactTraining/react-router/blob/master/packages/react-router/modules/Redirect.js#L46,L60

React Router v4 - Externally Mutate History Object

If you still need to do something similar to v2's implementation, you can create a copy of BrowserRouter then expose the history as an exportable constant. Below is a basic example but you can compose it to inject it with customizable props if needed. There are noted caveats with lifecycles, but it should always rerender the Router, just like in v2. This can be useful for redirects after an API request from an action function.

// browser router file...
import createHistory from 'history/createBrowserHistory';
import { Router } from 'react-router';

export const history = createHistory();

export default class BrowserRouter extends Component {
  render() {
    return <Router history={history} children={this.props.children} />
  }
}

// your main file...
import BrowserRouter from './relative/path/to/BrowserRouter';
import { render } from 'react-dom';

render(
  <BrowserRouter>
    <App/>
  </BrowserRouter>
);

// some file... where you don't have React instance references
import { history } from './relative/path/to/BrowserRouter';

history.push('/sample');

Latest BrowserRouter to extend: https://github.com/ReactTraining/react-router/blob/master/packages/react-router-dom/modules/BrowserRouter.js

React Router v2

Push a new state to the browserHistory instance:

import {browserHistory} from 'react-router';
// ...
browserHistory.push('/sample');

Reference: https://github.com/reactjs/react-router/blob/master/docs/guides/NavigatingOutsideOfComponents.md

How to update primary key

If you are sure that this change is suitable for the environment you're working in: set the FK conditions on the secondary tables to UPDATE CASCADING.

For example, if using SSMS as GUI:

  1. right click on the key
  2. select Modify
  3. Fold out 'INSERT And UPDATE Specific'
  4. For 'Update Rule', select Cascade.
  5. Close the dialog and save the key.

When you then update a value in the PK column in your primary table, the FK references in the other tables will be updated to point at the new value, preserving data integrity.

how to re-format datetime string in php?

For PHP 5 >= 5.3.0 http://www.php.net/manual/en/datetime.createfromformat.php

$datetime = "20130409163705"; 
$d = DateTime::createFromFormat("YmdHis", $datetime);
echo $d->format("d/m/Y H:i:s"); // or any you want

Result:

09/04/2013 16:37:05

Java8: sum values from specific field of the objects in a list

In Java 8 for an Obj entity with field and getField() method you can use:

List<Obj> objs ...

Stream<Obj> notNullObjs =
  objs.stream().filter(obj -> obj.getValue() != null);

Double sum = notNullObjs.mapToDouble(Obj::getField).sum();

Change Active Menu Item on Page Scroll?

If you want the accepted answer to work in JQuery 3 change the code like this:

var scrollItems = menuItems.map(function () {
    var id = $(this).attr("href");
    try {
        var item = $(id);
      if (item.length) {
        return item;
      }
    } catch {}
  });

I also added a try-catch to prevent javascript from crashing if there is no element by that id. Feel free to improve it even more ;)

Solution to INSTALL_FAILED_INSUFFICIENT_STORAGE error on Android

After trying out everything else in this thread, I found out my own problem was because the path to the .apk file was too long. So I cd'ed to the directory where the .apk was in and did:

cd /Very/Long/Path/To/Package/
adb install mypackage.apk

instead of

adb install /Very/Long/Path/To/Package/mypackage.apk

And it worked...installed just fine.

Just thought this might help someone else.

Why should I use IHttpActionResult instead of HttpResponseMessage?

I'd rather implement TaskExecuteAsync interface function for IHttpActionResult. Something like:

    public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
    {
        var response = _request.CreateResponse(HttpStatusCode.InternalServerError, _respContent);

        switch ((Int32)_respContent.Code)
        { 
            case 1:
            case 6:
            case 7:
                response = _request.CreateResponse(HttpStatusCode.InternalServerError, _respContent);
                break;
            case 2:
            case 3:
            case 4:
                response = _request.CreateResponse(HttpStatusCode.BadRequest, _respContent);
                break;
        } 

        return Task.FromResult(response);
    }

, where _request is the HttpRequest and _respContent is the payload.

Height of an HTML select box (dropdown)

NO. It's not possible to change height of a select dropdown because that property is browser specific.

However if you want that functionality, then there are many options. You can use bootstrap dropdown-menu and define it's max-height property. Something like this.

_x000D_
_x000D_
$('.dropdown-menu').on( 'click', 'a', function() {_x000D_
    var text = $(this).html();_x000D_
    var htmlText = text + ' <span class="caret"></span>';_x000D_
    $(this).closest('.dropdown').find('.dropdown-toggle').html(htmlText);_x000D_
});
_x000D_
.dropdown-menu {_x000D_
    max-height: 146px;_x000D_
    overflow: scroll;_x000D_
    overflow-x: hidden;_x000D_
    margin-top: 0px;_x000D_
}_x000D_
_x000D_
.caret {_x000D_
   float: right;_x000D_
    margin-top: 5%;_x000D_
}_x000D_
_x000D_
#menu1 {_x000D_
    width: 160px; _x000D_
    text-align: left;_x000D_
}
_x000D_
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">_x000D_
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>_x000D_
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>_x000D_
   _x000D_
<div class="container" style="margin:10px">_x000D_
  <div class="dropdown">_x000D_
    <button class="btn btn-default dropdown-toggle" type="button" id="menu1" data-toggle="dropdown">Tutorials_x000D_
    <span class="caret"></span></button>_x000D_
    <ul class="dropdown-menu" role="menu" aria-labelledby="menu1">_x000D_
      <li><a href="#">HTML</a></li>_x000D_
      <li><a href="#">CSS</a></li>_x000D_
      <li><a href="#">JavaScript</a></li>_x000D_
      <li><a href="#">About Us</a></li>_x000D_
      <li><a href="#">HTML</a></li>_x000D_
      <li><a href="#">CSS</a></li>_x000D_
      <li><a href="#">JavaScript</a></li>_x000D_
      <li><a href="#">About Us</a></li>_x000D_
      <li><a href="#">HTML</a></li>_x000D_
      <li><a href="#">CSS</a></li>_x000D_
      <li><a href="#">JavaScript</a></li>_x000D_
      <li><a href="#">About Us</a></li>_x000D_
      <li><a href="#">HTML</a></li>_x000D_
      <li><a href="#">CSS</a></li>_x000D_
      <li><a href="#">JavaScript</a></li>_x000D_
      <li><a href="#">About Us</a></li>_x000D_
      <li><a href="#">HTML</a></li>_x000D_
      <li><a href="#">CSS</a></li>_x000D_
      <li><a href="#">JavaScript</a></li>_x000D_
      <li><a href="#">About Us</a></li>_x000D_
      <li><a href="#">HTML</a></li>_x000D_
      <li><a href="#">CSS</a></li>_x000D_
      <li><a href="#">JavaScript</a></li>_x000D_
      <li><a href="#">About Us</a></li>_x000D_
    </ul>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

java.net.ConnectException: Connection refused

Hope my experience may be useful to someone. I faced the problem with the same exception stack trace and I couldn't understand what the issue was. The Database server which I was trying to connect was running and the port was open and was accepting connections.

The issue was with internet connection. The internet connection that I was using was not allowed to connect to the corresponding server. When I changed the connection details, the issue got resolved.

How to remove specific elements in a numpy array

Remove specific index(i removed 16 and 21 from matrix)

import numpy as np
mat = np.arange(12,26)
a = [4,9]
del_map = np.delete(mat, a)
del_map.reshape(3,4)

Output:

array([[12, 13, 14, 15],
      [17, 18, 19, 20],
      [22, 23, 24, 25]])

adb shell command to make Android package uninstall dialog appear

Use this command in cmd:

adb shell pm uninstall -k com.packagename

For example:

adb shell pm uninstall -k com.fedmich.pagexray

The -k flag tells the package manager to keep the cache and data directories around, even though the app is removed. If you want a clean uninstall, don't specify -k.

in angularjs how to access the element that triggered the event?

The general Angular way to get access to an element that triggered an event is to write a directive and bind() to the desired event:

app.directive('myChange', function() {
  return function(scope, element) {
    element.bind('change', function() {
      alert('change on ' + element);
    });
  };
});

or with DDO (as per @tpartee's comment below):

app.directive('myChange', function() {
  return { 
    link:  function link(scope, element) {
      element.bind('change', function() {
        alert('change on ' + element);
      });
    }
  }
});

The above directive can be used as follows:

<input id="searchText" ng-model="searchText" type="text" my-change>

Plunker.

Type into the text field, then leave/blur. The change callback function will fire. Inside that callback function, you have access to element.

Some built-in directives support passing an $event object. E.g., ng-*click, ng-Mouse*. Note that ng-change does not support this event.

Although you can get the element via the $event object:

<button ng-click="clickit($event)">Hello</button>

$scope.clickit = function(e) {
    var elem = angular.element(e.srcElement);
    ...

this goes "deep against the Angular way" -- Misko.

How to start anonymous thread class

Add: now you can use lambda to simplify your syntax. Requirement: Java 8+

public class A {
    public static void main(String[] arg)
    {
        Thread th = new Thread(() -> {System.out.println("blah");});
        th.start();
    }
}

How to use curl to get a GET request exactly same as using Chrome?

Check the HTTP headers that chrome is sending with the request (Using browser extension or proxy) then try sending the same headers with CURL - Possibly one at a time till you figure out which header(s) makes the request work.

curl -A [user-agent] -H [headers] "http://something.com/api"

How to Get the Current URL Inside @if Statement (Blade) in Laravel 4?

Another way to write if and else in Laravel using path

 <p class="@if(Request::is('path/anotherPath/*')) className @else anotherClassName @endif" >
 </p>

Hope it helps

Docker: adding a file from a parent directory

If you are using skaffold, use 'context:' to specify context location for each image dockerfile - context: ../../../

            apiVersion: skaffold/v2beta4
            kind: Config
            metadata:
                name: frontend
            build:
                artifacts:
                    - image: nginx-angular-ui
                      context: ../../../
                      sync:
                          # A local build will update dist and sync it to the container
                          manual:
                              - src: './dist/apps'
                                dest: '/usr/share/nginx/html'
                      docker:
                          dockerfile: ./tools/pipelines/dockerfile/nginx.dev.dockerfile
                    - image: webapi/image
                      context: ../../../../api/
                      docker:
                          dockerfile: ./dockerfile
            deploy:
                kubectl:
                    manifests:
                        - ./.k8s/*.yml

skaffold run -f ./skaffold.yaml

DTO and DAO concepts and MVC

DTO is an abbreviation for Data Transfer Object, so it is used to transfer the data between classes and modules of your application.

  • DTO should only contain private fields for your data, getters, setters, and constructors.
  • DTO is not recommended to add business logic methods to such classes, but it is OK to add some util methods.

DAO is an abbreviation for Data Access Object, so it should encapsulate the logic for retrieving, saving and updating data in your data storage (a database, a file-system, whatever).

Here is an example of how the DAO and DTO interfaces would look like:

interface PersonDTO {
    String getName();
    void setName(String name);
    //.....
}

interface PersonDAO {
    PersonDTO findById(long id);
    void save(PersonDTO person);
    //.....
}

The MVC is a wider pattern. The DTO/DAO would be your model in the MVC pattern.
It tells you how to organize the whole application, not just the part responsible for data retrieval.

As for the second question, if you have a small application it is completely OK, however, if you want to follow the MVC pattern it would be better to have a separate controller, which would contain the business logic for your frame in a separate class and dispatch messages to this controller from the event handlers.
This would separate your business logic from the view.

How to append a newline to StringBuilder

It should be

r.append("\n");

But I recommend you to do as below,

r.append(System.getProperty("line.separator"));

System.getProperty("line.separator") gives you system-dependent newline in java. Also from Java 7 there's a method that returns the value directly: System.lineSeparator()

Add a properties file to IntelliJ's classpath

Faced a similar challenge adding files with .ini extensions to the classpath. Found this answer, which is to add it to Preferences -> Compiler -> Resource Patterns -> [...] ;*.ini

How to Set user name and Password of phpmyadmin

You can simply open the phpmyadmin page from your browser, then open any existing database -> go to Privileges tab, click on your root user and then a popup window will appear, you can set your password there.. Hope this Helps.

Angular ng-if not true

Use like this

<div ng-if="data.IsActive === 1">InActive</div>
<div ng-if="data.IsActive === 0">Active</div>

LogCat message: The Google Play services resources were not found. Check your project configuration to ensure that the resources are included

In my case it meant, there is some kind of mistake in my implementation, and it says that it cannot find the resource for the error message to be properly shown in LogCat. When I fixed that mistake in my implementation the problem from LogCat was gone as well. So actually unless you are missing some really neccessary resource you should not concentrate to fix the missing resources, but rather fix your implementation.

The mistake, BTW, was that I was running ads in debug mode without going to ads test mode.

Python MYSQL update statement

Neither of them worked for me for some reason.

I figured it out that for some reason python doesn't read %s. So use (?) instead of %S in you SQL Code.

And finally this worked for me.

   cursor.execute ("update tablename set columnName = (?) where ID = (?) ",("test4","4"))
   connect.commit()

How can I wait for a thread to finish with .NET?

When I want the UI to be able to update its display while waiting for a task to complete, I use a while-loop that tests IsAlive on the thread:

    Thread t = new Thread(() => someMethod(parameters));
    t.Start();
    while (t.IsAlive)
    {
        Thread.Sleep(500);
        Application.DoEvents();
    }

How to prevent multiple definitions in C?

You actually compile the source code of test.c twice:

  • The first time when compiling test.c itself,
  • The second time when compiling main.c which includes all the test.c source.

What you need in your main.c in order to use the test() function is a simple declaration, not its definition. This is achieved by including a test.h header file which contains something like:

void test(void);

This informs the compiler that such a function with input parameters and return type exists. What this function does ( everything inside { and } ) is left in your test.c file.

In main.c, replace #include "test.c" by #include "test.h".

A last point: with your programs being more complex, you will be faced to situations when header files may be included several times. To prevent this, header sources are sometimes enclosed by specific macro definitions, like:

#ifndef TEST_H_INCLUDED
#define TEST_H_INCLUDED

void test(void);

#endif

How to make Scrollable Table with fixed headers using CSS

I can think of a cheeky way to do it, I don't think this will be the best option but it will work.

Create the header as a separate table then place the other in a div and set a max size, then allow the scroll to come in by using overflow.

_x000D_
_x000D_
table {_x000D_
  width: 500px;_x000D_
}_x000D_
_x000D_
.scroll {_x000D_
  max-height: 60px;_x000D_
  overflow: auto;_x000D_
}
_x000D_
<table border="1">_x000D_
  <tr>_x000D_
  <th>head1</th>_x000D_
  <th>head2</th>_x000D_
  <th>head3</th>_x000D_
  <th>head4</th>_x000D_
  </tr>_x000D_
</table>_x000D_
<div class="scroll">_x000D_
  <table>_x000D_
    <tr><td>Text Text</td><td>Text Text</td><td>Text Text</td><td>Text Text</td></tr>_x000D_
    <tr><td>Text Text</td><td>Text Text</td><td>Text Text</td><td>Text Text</td></tr>_x000D_
    <tr><td>Text Text</td><td>Text Text</td><td>Text Text</td><td>Text Text</td></tr>_x000D_
    <tr><td>Text Text</td><td>Text Text</td><td>Text Text</td><td>Text Text</td></tr>_x000D_
    <tr><td>Text Text</td><td>Text Text</td><td>Text Text</td><td>Text Text</td></tr>_x000D_
    <tr><td>Text Text</td><td>Text Text</td><td>Text Text</td><td>Text Text</td></tr>_x000D_
    <tr><td>More Text</td><td>More Text</td><td>More Text</td><td>More Text</td></tr>_x000D_
    <tr><td>Text Text</td><td>Text Text</td><td>Text Text</td><td>Text Text</td></tr>_x000D_
    <tr><td>Even More Text Text</td><td>Even More Text Text</td><td>Even More Text Text</td><td>Even More Text Text</td></tr>_x000D_
  </table>_x000D_
</div>
_x000D_
_x000D_
_x000D_

How to copy a row and insert in same table with a autoincrement field in MySQL?

INSERT INTO `dbMyDataBase`.`tblMyTable` 
(
    `IdAutoincrement`, 
    `Column2`, 
    `Column3`, 
    `Column4` 
) 

SELECT 
    NULL,  
    `Column2`, 
    `Column3`, 
    'CustomValue' AS Column4 
FROM `dbMyDataBase`.`tblMyTable` 
WHERE `tblMyTable`.`Column2` = 'UniqueValueOfTheKey' 
; 
/* mySQL 5.6 */

Read environment variables in Node.js

When using Node.js, you can retrieve environment variables by key from the process.env object:

for example

var mode   = process.env.NODE_ENV;
var apiKey = process.env.apiKey; // '42348901293989849243'

Here is the answer that will explain setting environment variables in node.js

Bootstrap onClick button event

There is no show event in js - you need to bind your button either to the click event:

$('#id').on('click', function (e) {

     //your awesome code here

})

Mind that if your button is inside a form, you may prefer to bind the whole form to the submit event.

Why does dividing two int not yield the right value when assigned to double?

With very few exceptions (I can only think of one), C++ determines the entire meaning of an expression (or sub-expression) from the expression itself. What you do with the results of the expression doesn't matter. In your case, in the expression a / b, there's not a double in sight; everything is int. So the compiler uses integer division. Only once it has the result does it consider what to do with it, and convert it to double.

SHA-256 or MD5 for file integrity

It is technically approved that MD5 is faster than SHA256 so in just verifying file integrity it will be sufficient and better for performance.

You are able to checkout the following resources:

Convert list to array in Java

Try this:

List list = new ArrayList();
list.add("Apple");
list.add("Banana");

Object[] ol = list.toArray();