Programs & Examples On #Windows identity

PHP error: php_network_getaddresses: getaddrinfo failed: (while getting information from other site.)

In my case this was being issued by wp cli, and the problem was that I didn't have php7.3-curl installed. Fixed with: apt-get install -y --quiet php7.3-curl

How do I get the current Date/time in DD/MM/YYYY HH:MM format?

require 'date'

current_time = DateTime.now

current_time.strftime "%d/%m/%Y %H:%M"
# => "14/09/2011 17:02"

current_time.next_month.strftime "%d/%m/%Y %H:%M"
# => "14/10/2011 17:02"

Box-Shadow on the left side of the element only

box-shadow: inset 10px 0 0 0 red;

Appending a vector to a vector

If you would like to add vector to itself both popular solutions will fail:

std::vector<std::string> v, orig;

orig.push_back("first");
orig.push_back("second");

// BAD:
v = orig;
v.insert(v.end(), v.begin(), v.end());
// Now v contains: { "first", "second", "", "" }

// BAD:
v = orig;
std::copy(v.begin(), v.end(), std::back_inserter(v));
// std::bad_alloc exception is generated

// GOOD, but I can't guarantee it will work with any STL:
v = orig;
v.reserve(v.size()*2);
v.insert(v.end(), v.begin(), v.end());
// Now v contains: { "first", "second", "first", "second" }

// GOOD, but I can't guarantee it will work with any STL:
v = orig;
v.reserve(v.size()*2);
std::copy(v.begin(), v.end(), std::back_inserter(v));
// Now v contains: { "first", "second", "first", "second" }

// GOOD (best):
v = orig;
v.insert(v.end(), orig.begin(), orig.end()); // note: we use different vectors here
// Now v contains: { "first", "second", "first", "second" }

Cannot call getSupportFragmentManager() from activity

You need to extend FragmentActivity instead of Activity

ModuleNotFoundError: No module named 'sklearn'

You can just use pip for installing packages, even when you are using anaconda:

pip install -U scikit-learn scipy matplotlib

This should work for installing the package.

And for Python 3.x just use pip3:

pip3 install -U scikit-learn scipy matplotlib

Simple CSS: Text won't center in a button

As a more brute force method that I found worked for me:

First wrap the text inside the button in a span, and then apply this css to that span

var spanStyle = {
      position: "absolute",
      top: "50%",
      left: "50%",
      transform: "translate(-50%, -50%)"
    }

*above setup for inline styling

Razor view engine - How can I add Partial Views

If you don't want to duplicate code, and like me you just want to show stats, in your view model, you could just pass in the models you want to get data from like so:

public class GameViewModel
{
    public virtual Ship Ship { get; set; }
    public virtual GamePlayer GamePlayer { get; set; }     
}

Then, in your controller just run your queries on the respective models, pass them to the view model and return it, example:

GameViewModel PlayerStats = new GameViewModel();

GamePlayer currentPlayer = (from c in db.GamePlayer [more queries]).FirstOrDefault();

[code to check if results]

//pass current player into custom view model
PlayerStats.GamePlayer = currentPlayer;

Like I said, you should only really do this if you want to display stats from the relevant tables, and there's no other part of the CRUD process happening, for security reasons other people have mentioned above.

Can I pass an array as arguments to a method with variable arguments in Java?

jasonmp85 is right about passing a different array to String.format. The size of an array can't be changed once constructed, so you'd have to pass a new array instead of modifying the existing one.

Object newArgs = new Object[args.length+1];
System.arraycopy(args, 0, newArgs, 1, args.length);
newArgs[0] = extraVar; 
String.format(format, extraVar, args);

How to run an external program, e.g. notepad, using hyperlink?

Sorry this answer sucks, but you can't launch an just any external application via a click, as this would be a serious security issue, this functionality isn't available in HTML or javascript. Think of just launching cmd.exe with args...you want to launch WinMerge with arguments, but you can see the security problems introduced by allowing this for anything.

The only possibly viable exception I can think of would be a protocol handler (since these are explicitly defined handlers), like winmerge://, though the best way to pass 2 file parameters I'm not sure of, if it's an option it's worth looking into, but I'm not sure what you are or are not allowed to do to the client, so this may be a non-starter solution.

Android SDK location should not contain whitespace, as this cause problems with NDK tools

As long as you aren't using the NDK you can just ignore that warning.

By the way: This warning has nothing to do with parallel installations.

Default instance name of SQL Server Express

If you navigate to where you have installed SQLExpress, e.g.

C:\Program Files\Microsoft SQL Server\110\Tools\Binn

You can run SQLLocalDB.exe and get a list of the all instances installed on your machine.

C:\Program Files\Microsoft SQL Server\110\Tools\Binn>SqlLocalDB.exe info
MSSQLLocalDB
ProjectsV12
v11.0

Then you can get further information on the instance.

C:\Program Files\Microsoft SQL Server\110\Tools\Binn>SqlLocalDB.exe info MSSQLLocalDB Name: MSSQLLocalDB
Version: 13.0.1601.5
Shared name:
Owner: Domain\User
Auto-create: Yes
State: Stopped
Last start time: 22/09/2016 10:19:33
Instance pipe name:

How do you add CSS with Javascript?

Shortest One Liner

_x000D_
_x000D_
// One liner function:
const addCSS = s => document.head.appendChild(document.createElement("style")).innerHTML=s;

// Usage: 
addCSS("body{ background:red; }")
_x000D_
_x000D_
_x000D_

Python concatenate text files

Use shutil.copyfileobj.

It automatically reads the input files chunk by chunk for you, which is more more efficient and reading the input files in and will work even if some of the input files are too large to fit into memory:

import shutil

with open('output_file.txt','wb') as wfd:
    for f in ['seg1.txt','seg2.txt','seg3.txt']:
        with open(f,'rb') as fd:
            shutil.copyfileobj(fd, wfd)

Windows equivalent of linux cksum command

Here is a C# implementation of the *nix cksum command line utility for windows https://cksum.codeplex.com/

How to detect string which contains only spaces?

Trim your String value by creating a trim function

var text = "  ";
if($.trim(text.length == 0){
  console.log("Text is empty");
}
else
{
  console.log("Text is not empty");
}

Jersey Exception : SEVERE: A message body reader for Java class

To make it work you only need two things. Check if you are missing:

  1. First of all, you need @XmlRootElement annotation for your object class/entity.
  2. You need to add dependency for jersey-json if you are missing.For your reference I added this dependency into my pom.xml.

    <dependency>
        <groupId>com.sun.jersey</groupId>
        <artifactId>jersey-json</artifactId>
        <version>1.17.1</version>
    </dependency>
    

What is the cleanest way to ssh and run multiple commands in Bash?

For anyone stumbling over here like me - I had success with escaping the semicolon and the newline:

First step: the semicolon. This way, we do not break the ssh command:

ssh <host> echo test\;ls
                    ^ backslash!

Listed the remote hosts /home directory (logged in as root), whereas

ssh <host> echo test;ls
                    ^ NO backslash

listed the current working directory.

Next step: breaking up the line:

                      v another backslash!
ssh <host> echo test\;\
ls

This again listed the remote working directory - improved formatting:

ssh <host>\
  echo test\;\
  ls

If really nicer than here document or quotes around broken lines - well, not me to decide...

(Using bash, Ubuntu 14.04 LTS.)

Removing header column from pandas dataframe

Haven't seen this solution yet so here's how I did it without using read_csv:

df.rename(columns={'A':'','B':''})

If you rename all your column names to empty strings your table will return without a header.

And if you have a lot of columns in your table you can just create a dictionary first instead of renaming manually:

df_dict = dict.fromkeys(df.columns, '')
df.rename(columns = df_dict)

CAST to DECIMAL in MySQL

From MySQL docs: Fixed-Point Types (Exact Value) - DECIMAL, NUMERIC:

In standard SQL, the syntax DECIMAL(M) is equivalent to DECIMAL(M,0)

So, you are converting to a number with 2 integer digits and 0 decimal digits. Try this instead:

CAST((COUNT(*) * 1.5) AS DECIMAL(12,2)) 

SVN Commit specific files

Use changelists. The advantage over specifying files is that you can visualize and confirm everything you wanted is actually included before you commit.

$ svn changelist fix-issue-237 foo.c 
Path 'foo.c' is now a member of changelist 'fix-issue-237'.

That done, svn now keeps things separate for you. This helps when you're juggling multiple changes

$ svn status
A       bar.c
A       baz.c

--- Changelist 'fix-issue-237':
A       foo.c

Finally, tell it to commit what you wanted changed.

$ svn commit --changelist fix-issue-237 -m "Issue 237"

Error executing command 'ant' on Mac OS X 10.9 Mavericks when building for Android with PhoneGap/Cordova

As an alternative to homebrew, you could download and install macports. Once you have macports, you can use:

sudo port install apache-ant

Why does multiplication repeats the number several times?

You cannot multiply an integer by a string. To be sure, you could try using the int (short for integer which means whole number) command, like this for example -

firstNumber = int(9)
secondNumber = int(1)
answer = (firstNumber*secondNumber)

Hope that helped :)

Embed a PowerPoint presentation into HTML

Google Docs allows you to upload a PowerPoint document, you can then 'Share' it with everyone then you can 'Publish' it and this will provide code to embed it in your site or you can use a direct link which runs at the full size of the browser window. The conversion is pretty good and scales well because the text is retained rather than converted to an image. The conversion is pretty good and the whole thing is free. Definitely worth a go.

How to set level logging to DEBUG in Tomcat?

Firstly, the level name to use is FINE, not DEBUG. Let's assume for a minute that DEBUG is actually valid, as it makes the following explanation make a bit more sense...

In the Handler specific properties section, you're setting the logging level for those handlers to DEBUG. This means the handlers will handle any log messages with the DEBUG level or higher. It doesn't necessarily mean any DEBUG messages are actually getting passed to the handlers.

In the Facility specific properties section, you're setting the logging level for a few explicitly-named loggers to DEBUG. For those loggers, anything at level DEBUG or above will get passed to the handlers.

The default logging level is INFO, and apart from the loggers mentioned in the Facility specific properties section, all loggers will have that level.

If you want to see all FINE messages, add this:

.level = FINE

However, this will generate a vast quantity of log messages. It's probably more useful to set the logging level for your code:

your.package.level = FINE

See the Tomcat 6/Tomcat 7 logging documentation for more information. The example logging.properties file shown there uses FINE instead of DEBUG:

...
1catalina.org.apache.juli.FileHandler.level = FINE
...

and also gives you examples of setting additional logging levels:

# For example, set the com.xyz.foo logger to only log SEVERE
# messages:
#org.apache.catalina.startup.ContextConfig.level = FINE
#org.apache.catalina.startup.HostConfig.level = FINE
#org.apache.catalina.session.ManagerBase.level = FINE

XMLHttpRequest cannot load XXX No 'Access-Control-Allow-Origin' header

As this isn't mentioned in the accepted answer.

  • This is not the case for this exact question, but might help others that search for that problem
  • This is something you can do in your client-code to prevent CORS errors in some cases.

You can make use of Simple Requests.
In order to perform a 'Simple Requests' the request needs to meet several conditions. E.g. only allowing POST, GET and HEAD method, as well as only allowing some given Headers (you can find all conditions here).

If your client code does not explicit set affected Headers (e.g. "Accept") with a fix value in the request it might occur that some clients do set these Headers automatically with some "non-standard" values causing the server to not accept it as Simple Request - which will give you a CORS error.

Download/Stream file from URL - asp.net

If you are looking for a .NET Core version of @Dallas's answer, use the below.

        Stream stream = null;

        //This controls how many bytes to read at a time and send to the client
        int bytesToRead = 10000;

        // Buffer to read bytes in chunk size specified above
        byte[] buffer = new Byte[bytesToRead];

        // The number of bytes read
        try
        {
            //Create a WebRequest to get the file
            HttpWebRequest fileReq = (HttpWebRequest)HttpWebRequest.Create(@"file url");

            //Create a response for this request
            HttpWebResponse fileResp = (HttpWebResponse)fileReq.GetResponse();

            if (fileReq.ContentLength > 0)
                fileResp.ContentLength = fileReq.ContentLength;

            //Get the Stream returned from the response
            stream = fileResp.GetResponseStream();

            // prepare the response to the client. resp is the client Response
            var resp = HttpContext.Response;

            //Indicate the type of data being sent
            resp.ContentType = "application/octet-stream";

            //Name the file 
            resp.Headers.Add("Content-Disposition", "attachment; filename=test.zip");
            resp.Headers.Add("Content-Length", fileResp.ContentLength.ToString());

            int length;
            do
            {
                // Verify that the client is connected.
                if (!HttpContext.RequestAborted.IsCancellationRequested)
                {
                    // Read data into the buffer.
                    length = stream.Read(buffer, 0, bytesToRead);

                    // and write it out to the response's output stream
                    resp.Body.Write(buffer, 0, length);


                    //Clear the buffer
                    buffer = new Byte[bytesToRead];
                }
                else
                {
                    // cancel the download if client has disconnected
                    length = -1;
                }
            } while (length > 0); //Repeat until no data is read
        }
        finally
        {
            if (stream != null)
            {
                //Close the input stream
                stream.Close();
            }
        }

How to trim a string to N chars in Javascript?

    let trimString = function (string, length) {
      return string.length > length ? 
             string.substring(0, length) + '...' :
             string;
    };

Use Case,

let string = 'How to trim a string to N chars in Javascript';

trimString(string, 20);

//How to trim a string...

time.sleep -- sleeps thread or process?

It blocks the thread. If you look in Modules/timemodule.c in the Python source, you'll see that in the call to floatsleep(), the substantive part of the sleep operation is wrapped in a Py_BEGIN_ALLOW_THREADS and Py_END_ALLOW_THREADS block, allowing other threads to continue to execute while the current one sleeps. You can also test this with a simple python program:

import time
from threading import Thread

class worker(Thread):
    def run(self):
        for x in xrange(0,11):
            print x
            time.sleep(1)

class waiter(Thread):
    def run(self):
        for x in xrange(100,103):
            print x
            time.sleep(5)

def run():
    worker().start()
    waiter().start()

Which will print:

>>> thread_test.run()
0
100
>>> 1
2
3
4
5
101
6
7
8
9
10
102

Why does Oracle not find oci.dll?

I just installed Oracle Instant Client 18_3 with the SDK. The PATH and ENV variable is set as instructed on the install page but I get the OCl.dll not found error. I searched the entire drive recursively and no such DLL exists.

So now what?

With the install instructions (not updated for 18_3) and downloads there are MISTAKES at step 13, so watch out for that.

When you create the folder structure for the downloads just write them the old way "c:\oraclient". Then when you unzip the basic, SDK and instant Client install for Windows 10_x64 extract them to "C:\oraclient\", because they all write to the same default folder. Then, when you set the ENV variable (which is no longer ORACLE_HOME, but now is OCI_LIB64) and the PATH, you will point to "C:\oraclient\instantclient_18_3".

To be sure you got it all right drill down and look for any duplicate "instantclient_18_3" folders. If you do have those cut and paste the CONTENTS to the root folder "C:\oraclient\instantclient_18_3\" folder.

Whoever works on the documentation at Oracle needs to troubleshoot better. I've seen "C:\oreclient_dir_install", "c:\oracle", "c:\oreclient" and "c:\oraclient" all mentioned as install directories, all for Windows x64 installs

BTW, install the C++ redist it helps. The 18.3 Basic package requires the Microsoft Visual Studio 2013 Redistributable.

What's the difference of $host and $http_host in Nginx

$host is a variable of the Core module.

$host

This variable is equal to line Host in the header of request or name of the server processing the request if the Host header is not available.

This variable may have a different value from $http_host in such cases: 1) when the Host input header is absent or has an empty value, $host equals to the value of server_name directive; 2)when the value of Host contains port number, $host doesn't include that port number. $host's value is always lowercase since 0.8.17.

$http_host is also a variable of the same module but you won't find it with that name because it is defined generically as $http_HEADER (ref).

$http_HEADER

The value of the HTTP request header HEADER when converted to lowercase and with 'dashes' converted to 'underscores', e.g. $http_user_agent, $http_referer...;


Summarizing:

  • $http_host equals always the HTTP_HOST request header.
  • $host equals $http_host, lowercase and without the port number (if present), except when HTTP_HOST is absent or is an empty value. In that case, $host equals the value of the server_name directive of the server which processed the request.

What is the difference between Views and Materialized Views in Oracle?

A view uses a query to pull data from the underlying tables.

A materialized view is a table on disk that contains the result set of a query.

Materialized views are primarily used to increase application performance when it isn't feasible or desirable to use a standard view with indexes applied to it. Materialized views can be updated on a regular basis either through triggers or by using the ON COMMIT REFRESH option. This does require a few extra permissions, but it's nothing complex. ON COMMIT REFRESH has been in place since at least Oracle 10.

"Field has incomplete type" error

The problem is that your ui property uses a forward declaration of class Ui::MainWindowClass, hence the "incomplete type" error.

Including the header file in which this class is declared will fix the problem.

EDIT

Based on your comment, the following code:

namespace Ui
{
    class MainWindowClass;
}

does NOT declare a class. It's a forward declaration, meaning that the class will exist at some point, at link time.
Basically, it just tells the compiler that the type will exist, and that it shouldn't warn about it.

But the class has to be defined somewhere.

Note this can only work if you have a pointer to such a type.
You can't have a statically allocated instance of an incomplete type.

So either you actually want an incomplete type, and then you should declare your ui member as a pointer:

namespace Ui
{
    // Forward declaration - Class will have to exist at link time
    class MainWindowClass;
}

class MainWindow : public QMainWindow
{
    private:

        // Member needs to be a pointer, as it's an incomplete type
        Ui::MainWindowClass * ui;
};

Or you want a statically allocated instance of Ui::MainWindowClass, and then it needs to be declared. You can do it in another header file (usually, there's one header file per class).
But simply changing the code to:

namespace Ui
{
    // Real class declaration - May/Should be in a specific header file
    class MainWindowClass
    {};
}


class MainWindow : public QMainWindow
{
    private:

        // Member can be statically allocated, as the type is complete
        Ui::MainWindowClass ui;
};

will also work.

Note the difference between the two declarations. First uses a forward declaration, while the second one actually declares the class (here with no properties nor methods).

Regex to match any character including new lines

Add the s modifier to your regex to cause . to match newlines:

$string =~ /(START)(.+?)(END)/s;

Database development mistakes made by application developers

Number one problem? They only test on toy databases. So they have no idea that their SQL will crawl when the database gets big, and someone has to come along and fix it later (that sound you can hear is my teeth grinding).

Why I'm getting 'Non-static method should not be called statically' when invoking a method in a Eloquent model?

Just in case this helps someone, I was getting this error because I completely missed the stated fact that the scope prefix must not be used when calling a local scope. So if you defined a local scope in your model like this:

public function scopeRecentFirst($query)
{
    return $query->orderBy('updated_at', 'desc');
}

You should call it like:

$CurrentUsers = \App\Models\Users::recentFirst()->get();

Note that the prefix scope is not present in the call.

What does "for" attribute do in HTML <label> tag?

The for attribute shows that this label stands for related input field, or check box or radio button or any other data entering field associated with it. for example

<li>
    <label>{translate:blindcopy}</label>
    <a class="" href="#" title="{translate:savetemplate}" onclick="" ><i class="fa fa-list" class="button" ></i></a> &nbsp 
            <input type="text" id="BlindCopy" name="BlindCopy" class="splitblindcopy" />

</li>

How to fix error "Updating Maven Project". Unsupported IClasspathEntry kind=4?

I couldn't get mvn eclipse:clean etc to work with Kepler.

However I changed creating and extending variables to just using external jars in my eclipse classpath. This was reflected in no var's in my .classpath.

This corrected the problem. I was able to do a Maven update.

Can jQuery get all CSS styles associated with an element?

A couple years late, but here is a solution that retrieves both inline styling and external styling:

function css(a) {
    var sheets = document.styleSheets, o = {};
    for (var i in sheets) {
        var rules = sheets[i].rules || sheets[i].cssRules;
        for (var r in rules) {
            if (a.is(rules[r].selectorText)) {
                o = $.extend(o, css2json(rules[r].style), css2json(a.attr('style')));
            }
        }
    }
    return o;
}

function css2json(css) {
    var s = {};
    if (!css) return s;
    if (css instanceof CSSStyleDeclaration) {
        for (var i in css) {
            if ((css[i]).toLowerCase) {
                s[(css[i]).toLowerCase()] = (css[css[i]]);
            }
        }
    } else if (typeof css == "string") {
        css = css.split("; ");
        for (var i in css) {
            var l = css[i].split(": ");
            s[l[0].toLowerCase()] = (l[1]);
        }
    }
    return s;
}

Pass a jQuery object into css() and it will return an object, which you can then plug back into jQuery's $().css(), ex:

var style = css($("#elementToGetAllCSS"));
$("#elementToPutStyleInto").css(style);

:)

Laravel: Get base url

Updates from 2018 Laravel release(5.7) documentation with some more url() functions and it's usage.

Question: To get the site's URL in Laravel?

This is kind of a general question, so we can split it.

1. Accessing The Base URL

// Get the base URL.
echo url('');

// Get the app URL from configuration which we set in .env file.
echo config('app.url'); 

2. Accessing The Current URL

// Get the current URL without the query string.
echo url()->current();

// Get the current URL including the query string.
echo url()->full();

// Get the full URL for the previous request.
echo url()->previous();

3. URLs For Named Routes

// http://example.com/home
echo route('home');

4. URLs To Assets(Public)

// Get the URL to the assets, mostly the base url itself.
echo asset('');

5. File URLs

use Illuminate\Support\Facades\Storage;

$url = Storage::url('file.jpg'); // stored in /storage/app/public
echo url($url);

Each of these methods may also be accessed via the URL facade:

use Illuminate\Support\Facades\URL;

echo URL::to(''); // Base URL
echo URL::current(); // Current URL

How to call these Helper functions from blade Template(Views) with usage.

// http://example.com/login
{{ url('/login') }}

// http://example.com/css/app.css
{{ asset('css/app.css') }}

// http://example.com/login
{{ route('login') }}

// usage

<!-- Styles -->
<link href="{{ asset('css/app.css') }}" rel="stylesheet">

<!-- Login link -->
<a class="nav-link" href="{{ route('login') }}">Login</a>

<!-- Login Post URL -->
<form method="POST" action="{{ url('/login') }}">

Test if registry value exists

My version:

Function Test-RegistryValue($Key, $Name)
{
    (Get-ChildItem (Split-Path -Parent -Path $Key) | Where-Object {$_.PSChildName -eq (Split-Path -Leaf $Key)}).Property -contains $Name
}

check if command was successful in a batch file

Most commands/programs return a 0 on success and some other value, called errorlevel, to signal an error.

You can check for this in you batch for example by:

call <THE_COMMAND_HERE>
if %ERRORLEVEL% == 0 goto :next
echo "Errors encountered during execution.  Exited with status: %errorlevel%"
goto :endofscript

:next
echo "Doing the next thing"

:endofscript
echo "Script complete"

Bring element to front using CSS

Another Note: z-index must be considered when looking at children objects relative to other objects.

For example

<div class="container">
    <div class="branch_1">
        <div class="branch_1__child"></div>
    </div>
    <div class="branch_2">
        <div class="branch_2__child"></div>
    </div>
</div>

If you gave branch_1__child a z-index of 99 and you gave branch_2__child a z-index of 1, but you also gave your branch_2 a z-index of 10 and your branch_1 a z-index of 1, your branch_1__child still will not show up in front of your branch_2__child

Anyways, what I'm trying to say is; if a parent of an element you'd like to be placed in front has a lower z-index than its relative, that element will not be placed higher.

The z-index is relative to its containers. A z-index placed on a container farther up in the hierarchy basically starts a new "layer"

Incep[inception]tion

Here's a fiddle to play around:

https://jsfiddle.net/orkLx6o8/

How to find MySQL process list and to kill those processes?

You can do something like this to check if any mysql process is running or not:

ps aux | grep mysqld
ps aux | grep mysql

Then if it is running you can killall by using(depending on what all processes are running currently):

killall -9 mysql
killall -9 mysqld
killall -9 mysqld_safe    

How to do perspective fixing?

The simple solution is to just remap coordinates from the original to the final image, copying pixels from one coordinate space to the other, rounding off as necessary -- which may result in some pixels being copied several times adjacent to each other, and other pixels being skipped, depending on whether you're stretching or shrinking (or both) in either dimension. Make sure your copying iterates through the destination space, so all pixels are covered there even if they're painted more than once, rather than thru the source which may skip pixels in the output.

The better solution involves calculating the corresponding source coordinate without rounding, and then using its fractional position between pixels to compute an appropriate average of the (typically) four pixels surrounding that location. This is essentially a filtering operation, so you lose some resolution -- but the result looks a LOT better to the human eye; it does a much better job of retaining small details and avoids creating straight-line artifacts which humans find objectionable.

Note that the same basic approach can be used to remap flat images onto any other shape, including 3D surface mapping.

CSS: Set a background color which is 50% of the width of the window

Older Browser Support

If older browser support is a must, so you can't go with multiple backgrounds or gradients, you're probably going to want to do something like this on a spare div element:

#background {
    position: fixed;
    top: 0;
    left: 0;
    width: 50%;
    height: 100%;
    background-color: pink; 
}

Example: http://jsfiddle.net/PLfLW/1704/

The solution uses an extra fixed div that fills half the screen. Since it's fixed, it will remain in position even when your users scroll. You may have to fiddle with some z-indexes later, to make sure your other elements are above the background div, but it shouldn't be too complex.

If you have issues, just make sure the rest of your content has a z-index higher than the background element and you should be good to go.


Modern Browsers

If newer browsers are your only concern, there are a couple other methods you can use:

Linear Gradient:

This is definitely the easiest solution. You can use a linear-gradient in the background property of the body for a variety of effects.

body {
    height: 100%;
    background: linear-gradient(90deg, #FFC0CB 50%, #00FFFF 50%);
}

This causes a hard cutoff at 50% for each color, so there isn't a "gradient" as the name implies. Try experimenting with the "50%" piece of the style to see the different effects you can achieve.

Example: http://jsfiddle.net/v14m59pq/2/

Multiple Backgrounds with background-size:

You can apply a background color to the html element, and then apply a background-image to the body element and use the background-size property to set it to 50% of the page width. This results in a similar effect, though would really only be used over gradients if you happen to be using an image or two.

html {
    height: 100%;
    background-color: cyan;
}

body {
    height: 100%;
    background-image: url('http://i.imgur.com/9HMnxKs.png');
    background-repeat: repeat-y;
    background-size: 50% auto;
}

Example: http://jsfiddle.net/6vhshyxg/2/


EXTRA NOTE: Notice that both the html and body elements are set to height: 100% in the latter examples. This is to make sure that even if your content is smaller than the page, the background will be at least the height of the user's viewport. Without the explicit height, the background effect will only go down as far as your page content. It's also just a good practice in general.

Ways to circumvent the same-origin policy

The Reverse Proxy method

  • Method type: Ajax

Setting up a simple reverse proxy on the server, will allow the browser to use relative paths for the Ajax requests, while the server would be acting as a proxy to any remote location.

If using mod_proxy in Apache, the fundamental configuration directive to set up a reverse proxy is the ProxyPass. It is typically used as follows:

ProxyPass     /ajax/     http://other-domain.com/ajax/

In this case, the browser would be able to request /ajax/web_service.xml as a relative URL, but the server would serve this by acting as a proxy to http://other-domain.com/ajax/web_service.xml.

One interesting feature of the this method is that the reverse proxy can easily distribute requests towards multiple back-ends, thus acting as a load balancer.

Notepad++: Multiple words search in a file (may be in different lines)?

You need a new version of notepad++. Looks like old versions don't support |.

Note: egrep "CAT|TOWN" will search for lines containing CATOWN. (CAT)|(TOWN) is the proper or extension (matching 1,3,4). Strangely you wrote and which is btw (CAT.*TOWN)|(TOWN.*CAT)

How to get main div container to align to centre?

The basic principle of centering a page is to have a body CSS and main_container CSS. It should look something like this:

body {
     margin: 0;
     padding: 0;
     text-align: center;
}
#main_container {
     margin: 0 auto;
     text-align: left;
}

How do you comment an MS-access Query?

The first answer mentioned how to get the description property programatically. If you're going to bother with program anyway, since the comments in the query are so kludgy, instead of trying to put the comments in the query, maybe it's better to put them in a program and use the program to make all your queries

Dim dbs As DAO.Database
Dim qry As DAO.QueryDef

Set dbs = CurrentDb
'put your comments wherever in your program makes the most sense
dbs.QueryDefs("qryName").SQL = "SELECT whatever.fields FROM whatever_table;"
DoCmd.OpenQuery "qryname"

How to add a new line in textarea element?

You might want to use \n instead of /n.

Auto reloading python Flask app upon code changes

Flask applications can optionally be executed in debug mode. In this mode, two very convenient modules of the development server called the reloader and the debugger are enabled by default. When the reloader is enabled, Flask watches all the source code files of your project and automatically restarts the server when any of the files are modified.

By default, debug mode is disabled. To enable it, set a FLASK_DEBUG=1 environment variable before invoking flask run:

(venv) $ export FLASK_APP=hello.py for Windows use > set FLASK_APP=hello.py

(venv) $ export FLASK_DEBUG=1 for Windows use > set FLASK_DEBUG=1

(venv) $ flask run

* Serving Flask app "hello"
* Forcing debug mode on
* Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
* Restarting with stat
* Debugger is active!
* Debugger PIN: 273-181-528

Having a server running with the reloader enabled is extremely useful during development, because every time you modify and save a source file, the server automatically restarts and picks up the change.

How to insert a row in an HTML table body in JavaScript

Basic approach:

This should add HTML-formatted content and show the newly added row.

var myHtmlContent = "<h3>hello</h3>"
var tableRef = document.getElementById('myTable').getElementsByTagName('tbody')[0];

var newRow = tableRef.insertRow(tableRef.rows.length);
newRow.innerHTML = myHtmlContent;

Why cannot change checkbox color whatever I do?

Can be very simplified like that :

input[type="checkbox"]{
    outline:2px solid red;
    outline-offset: -2px;
}

Works without any plugin :)

no default constructor exists for class

A default constructor is a constructor that either has no parameters, or if it has parameters, all the parameters have default values.

Remove border from buttons

input[type="button"] {
border: none;
outline:none;
}

Spring Boot, Spring Data JPA with multiple DataSources

don't know why, but it works. Two configuration are the same, just change xxx to your name.

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
    entityManagerFactoryRef = "xxxEntityManager",
    transactionManagerRef = "xxxTransactionManager",
    basePackages = {"aaa.xxx"})
 public class RepositoryConfig {
@Autowired
private Environment env;

@Bean
@Primary
@ConfigurationProperties(prefix="datasource.xxx")
public DataSource xxxDataSource() {
    return DataSourceBuilder.create().build();
}

@Bean
public LocalContainerEntityManagerFactoryBean xxxEntityManager() {
    LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
    em.setDataSource(xxxDataSource());
    em.setPackagesToScan(new String[] {"aaa.xxx"});

    HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
    em.setJpaVendorAdapter(vendorAdapter);
    HashMap<String, Object> properties = new HashMap<String, Object>();
    properties.put("hibernate.show_sql", env.getProperty("hibernate.show_sql"));
    properties.put("hibernate.hbm2ddl.auto", env.getProperty("hibernate.hbm2ddl.auto"));
    properties.put("hibernate.dialect", env.getProperty("hibernate.dialect"));
    em.setJpaPropertyMap(properties);

    return em;
}

@Bean(name = "xxxTransactionManager")
public PlatformTransactionManager xxxTransactionManager() {
    JpaTransactionManager tm = new JpaTransactionManager();
    tm.setEntityManagerFactory(xxxEntityManager().getObject());
    return tm;
}

}

"Unknown class <MyClass> in Interface Builder file" error at runtime

Go to the "ProjectName" , click on it , and then go the "Build phases" tab , and then click on the "compile sources" , and then click on "+" button , a window will appear , the choose "MyClass.m" file and then click "add" ,

Build the Project and Run it , the problem will surely get solved out

What is the C++ function to raise a number to a power?

I don't have enough reputation to comment, but if you like working with QT, they have their own version.

    #include <QtCore/qmath.h>
    qPow(x, y); // returns x raised to the y power.

Or if you aren't using QT, cmath has basically the same thing.

    #include <cmath>
    double x = 5, y = 7; //As an example, 5 ^ 7 = 78125
    pow(x, y); //Should return this: 78125

Why doesn't margin:auto center an image?

You need to render it as block level;

img {
   display: block;
   width: auto;
   margin: auto;
}

Setting individual axis limits with facet_wrap and scales = "free" in ggplot2

I am not sure I understand what you want, but based on what I understood

the x scale seems to be the same, it is the y scale that is not the same, and that is because you specified scales ="free"

you can specify scales = "free_x" to only allow x to be free (in this case it is the same as pred has the same range by definition)

p <- ggplot(plot, aes(x = pred, y = value)) + geom_point(size = 2.5) + theme_bw()
p <- p + facet_wrap(~variable, scales = "free_x")

worked for me, see the picture

enter image description here

I think you were making it too difficult - I do seem to remember one time defining the limits based on a formula with min and max and if faceted I think it used only those values, but I can't find the code

Add vertical scroll bar to panel

AutoScroll is really the solution! You just have to set AutoScrollMargin to 0, 1000 or something like this, then use it to scroll down and add buttons and items there!

How can I create a memory leak in Java?

In Java a "memory leak" is primarily just you using too much memory which is different than in C where you are no longer using the memory but forget to return (free) it. When an interviewer asks about Java memory leaks they are asking about JVM memory usage just appearing to keep going up and they determined that restarting the JVM on a regular basis is the best fix. (unless the interviewer is extremely technically savvy)

So answer this question as if they asked what makes JVM memory usage grow over time. Good answers would be storing too much data in a HttpSessions with overly long timeout or a poorly implemented in-memory cache (Singleton) that never flushes old entries. Another potential answer is having lots of JSPs or dynamically generated classes. Classes are loaded into an area of memory called PermGen that is usually small and most JVMs don't implement class unloading.

Direct casting vs 'as' operator?

2 is useful for casting to a derived type.

Suppose a is an Animal:

b = a as Badger;
c = a as Cow;

if (b != null)
   b.EatSnails();
else if (c != null)
   c.EatGrass();

will get a fed with a minimum of casts.

org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set

Adding spring.jpa.database-platform=org.hibernate.dialect.MariaDB53Dialect to my properties file worked for me.

PS: i'm using MariaDB

Vuejs: v-model array in multiple input

If you were asking how to do it in vue2 and make options to insert and delete it, please, have a look an js fiddle

_x000D_
_x000D_
new Vue({_x000D_
  el: '#app',_x000D_
  data: {_x000D_
    finds: [] _x000D_
  },_x000D_
  methods: {_x000D_
    addFind: function () {_x000D_
      this.finds.push({ value: 'def' });_x000D_
    },_x000D_
    deleteFind: function (index) {_x000D_
      console.log(index);_x000D_
      console.log(this.finds);_x000D_
      this.finds.splice(index, 1);_x000D_
    }_x000D_
  }_x000D_
});
_x000D_
<script src="https://unpkg.com/[email protected]/dist/vue.js"></script>_x000D_
<div id="app">_x000D_
  <h1>Finds</h1>_x000D_
  <div v-for="(find, index) in finds">_x000D_
    <input v-model="find.value">_x000D_
    <button @click="deleteFind(index)">_x000D_
      delete_x000D_
    </button>_x000D_
  </div>_x000D_
  _x000D_
  <button @click="addFind">_x000D_
    New Find_x000D_
  </button>_x000D_
  _x000D_
  <pre>{{ $data }}</pre>_x000D_
</div>
_x000D_
_x000D_
_x000D_

How do I increase memory on Tomcat 7 when running as a Windows Service?

//ES/tomcat -> This may not work if you have changed the service name during the installation.

Either run the command without any service name

.\bin\tomcat7w.exe //ES

or with exact service name

.\bin\tomcat7w.exe //ES/YourServiceName

Spring not autowiring in unit tests with JUnit

You need to use the Spring JUnit runner in order to wire in Spring beans from your context. The code below assumes that you have a application context called testContest.xml available on the test classpath.

import org.hibernate.SessionFactory;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.transaction.annotation.Transactional;

import java.sql.SQLException;

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.startsWith;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath*:**/testContext.xml"})
@Transactional
public class someDaoTest {

    @Autowired
    protected SessionFactory sessionFactory;

    @Test
    public void testDBSourceIsCorrect() throws SQLException {
        String databaseProductName = sessionFactory.getCurrentSession()
                .connection()
                .getMetaData()
                .getDatabaseProductName();
        assertThat("Test container is pointing at the wrong DB.", databaseProductName, startsWith("HSQL"));
    }
}

Note: This works with Spring 2.5.2 and Hibernate 3.6.5

Difference between declaring variables before or in loop?

A co-worker prefers the first form, telling it is an optimization, preferring to re-use a declaration.

I prefer the second one (and try to persuade my co-worker! ;-)), having read that:

  • It reduces scope of variables to where they are needed, which is a good thing.
  • Java optimizes enough to make no significant difference in performance. IIRC, perhaps the second form is even faster.

Anyway, it falls in the category of premature optimization that rely in quality of compiler and/or JVM.

Launching an application (.EXE) from C#?

System.Diagnostics.Process.Start("PathToExe.exe");

ERROR in The Angular Compiler requires TypeScript >=3.1.1 and <3.2.0 but 3.2.1 was found instead

I also faced similar issues when tried to do ng serve. I was able to resolve it as below.
Note:

C:\Windows\system32> is on windows command prompt
C:\apps\workspace\testProj>  is on VS code Terminal (can also be doable in another command prompt)

Following are the steps which I used to resolve this.

Step1. Verify the cli version installed on command prompt (will be Angular CLI global version)

C:\Windows\system32>ng --version

Angular CLI: 8.3.13

If cli was installed earlier, it shows the global cli version.

If cli was not installed, we may get the error
ng is not recognized as an internal or external command

a. (Optional Step) Install Angular CLI global version

C:\Windows\system32>npm install -g @angular/cli
C:\Windows\system32>npm install -g @angular-cli/latest

b. Check version again

C:\Windows\system32>ng --version
Angular CLI: 8.3.13

Step2. Verify the local cli version installed on your angular project(VS code ide or command prompt cd'd to your project project)

C:\apps\workspace\testProj>ng --version
Angular CLI: 7.3.8

Note: Clearly versions are not in sync. Do the following in your angular project

C:\apps\workspace\testProj>ng update @angular/cli        -> important to sync with global cli version

Note: If upgrade donot work using above command (ref: How to upgrade Angular CLI to the latest version) On command prompt, uninstall global angular cli, clean the cache and reinstall the cli

C:\Windows\system32>npm uninstall -g angular-cli
C:\Windows\system32>npm cache clean or npm cache verify #(if npm > 5)
C:\Windows\system32>npm install -g @angular/cli@latest

Now update your local project version, because cli version of your local project is having higher priority than global one when you try to execute your project.

C:\apps\workspace\testProj>rm -rf node_modules
C:\apps\workspace\testProj>npm uninstall --save-dev angular-cli
C:\apps\workspace\testProj>npm install --save-dev @angular/cli@latest
C:\apps\workspace\testProj>npm install
C:\apps\workspace\testProj>ng update @angular/cli

Step3. Verify if local project cli version now in sync with global one

C:\Windows\system32>ng --version
Angular CLI: 8.3.13

C:\apps\workspace\testProj>ng --version
Angular CLI: 8.3.13

Step4.. Revalidate on the project

C:\apps\workspace\testProj>ng serve

Should work now

Copy a file list as text from Windows Explorer

In Windows 7 and later, this will do the trick for you

  • Select the file/files.
  • Hold the shift key and then right-click on the selected file/files.
  • You will see Copy as Path. Click that.
  • Open a Notepad file and paste and you will be good to go.

The menu item Copy as Path is not available in Windows XP.

How to programmatically set the Image source

myImg.Source = new BitmapImage(new Uri(@"component/Images/down.png", UriKind.RelativeOrAbsolute)); 

Don't forget to set Build Action to "Content", and Copy to output directory to "Always".

What is the meaning of 'No bundle URL present' in react-native?

For Mcafee Macbook users :

sudo launchctl remove com.mcafee.agent.macmn

How do synchronized static methods work in Java and can I use it for loading Hibernate entities?

How the synchronized Java keyword works

When you add the synchronized keyword to a static method, the method can only be called by a single thread at a time.

In your case, every method call will:

  • create a new SessionFactory
  • create a new Session
  • fetch the entity
  • return the entity back to the caller

However, these were your requirements:

  • I want this to prevent access to info to the same DB instance.
  • preventing getObjectById being called for all classes when it is called by a particular class

So, even if the getObjectById method is thread-safe, the implementation is wrong.

SessionFactory best practices

The SessionFactory is thread-safe, and it's a very expensive object to create as it needs to parse the entity classes and build the internal entity metamodel representation.

So, you shouldn't create the SessionFactory on every getObjectById method call.

Instead, you should create a singleton instance for it.

private static final SessionFactory sessionFactory = new Configuration()
    .configure()
    .buildSessionFactory();

The Session should always be closed

You didn't close the Session in a finally block, and this can leak database resources if an exception is thrown when loading the entity.

According to the Session.load method JavaDoc might throw a HibernateException if the entity cannot be found in the database.

You should not use this method to determine if an instance exists (use get() instead). Use this only to retrieve an instance that you assume exists, where non-existence would be an actual error.

That's why you need to use a finally block to close the Session, like this:

public static synchronized Object getObjectById (Class objclass, Long id) {    
     Session session = null;
     try {
         session = sessionFactory.openSession();
         return session.load(objclass, id);
     } finally {
         if(session != null) {
             session.close(); 
         }
     }
 }

Preventing multi-thread access

In your case, you wanted to make sure only one thread gets access to that particular entity.

But the synchronized keyword only prevents two threads from calling the getObjectById concurrently. If the two threads call this method one after the other, you will still have two threads using this entity.

So, if you want to lock a given database object so no other thread can modify it, then you need to use database locks.

The synchronized keyword only works in a single JVM. If you have multiple web nodes, this will not prevent multi-thread access across multiple JVMs.

What you need to do is use LockModeType.PESSIMISTIC_READ or LockModeType.PESSIMISTIC_WRITE while applying the changes to the DB, like this:

Session session = null;
EntityTransaction tx = null;

try {
    session = sessionFactory.openSession();
    
    tx = session.getTransaction();
    tx.begin();

    Post post = session.find(
        Post.class, 
        id, 
        LockModeType.LockModeType.PESSIMISTIC_READ
    );

    post.setTitle("High-Performance Java Perisstence");

    tx.commit();
} catch(Exception e) {
    LOGGER.error("Post entity could not be changed", e);
    if(tx != null) {
        tx.rollback(); 
    }
} finally {
    if(session != null) {
        session.close(); 
    }
}

So, this is what I did:

  • I created a new EntityTransaction and started a new database transaction
  • I loaded the Post entity while holding a lock on the associated database record
  • I changed the Post entity and committed the transaction
  • In the case of an Exception being thrown, I rolled back the transaction

Use a LIKE statement on SQL Server XML Datatype

You should be able to do this quite easily:

SELECT * 
FROM WebPageContent 
WHERE data.value('(/PageContent/Text)[1]', 'varchar(100)') LIKE 'XYZ%'

The .value method gives you the actual value, and you can define that to be returned as a VARCHAR(), which you can then check with a LIKE statement.

Mind you, this isn't going to be awfully fast. So if you have certain fields in your XML that you need to inspect a lot, you could:

  • create a stored function which gets the XML and returns the value you're looking for as a VARCHAR()
  • define a new computed field on your table which calls this function, and make it a PERSISTED column

With this, you'd basically "extract" a certain portion of the XML into a computed field, make it persisted, and then you can search very efficiently on it (heck: you can even INDEX that field!).

Marc

How to properly express JPQL "join fetch" with "where" clause as JPA 2 CriteriaQuery?

In JPQL the same is actually true in the spec. The JPA spec does not allow an alias to be given to a fetch join. The issue is that you can easily shoot yourself in the foot with this by restricting the context of the join fetch. It is safer to join twice.

This is normally more an issue with ToMany than ToOnes. For example,

Select e from Employee e 
join fetch e.phones p 
where p.areaCode = '613'

This will incorrectly return all Employees that contain numbers in the '613' area code but will left out phone numbers of other areas in the returned list. This means that an employee that had a phone in the 613 and 416 area codes will loose the 416 phone number, so the object will be corrupted.

Granted, if you know what you are doing, the extra join is not desirable, some JPA providers may allow aliasing the join fetch, and may allow casting the Criteria Fetch to a Join.

SQL Query Where Field DOES NOT Contain $x

SELECT * FROM table WHERE field1 NOT LIKE '%$x%'; (Make sure you escape $x properly beforehand to avoid SQL injection)

Edit: NOT IN does something a bit different - your question isn't totally clear so pick which one to use. LIKE 'xxx%' can use an index. LIKE '%xxx' or LIKE '%xxx%' can't.

Delete all lines starting with # or ; in Notepad++

Maybe you should try

^[#;].*$

^ matches the beggining, $ the end.

C#: calling a button event handler method without actually clicking the button

You can use reflection to Invoke the OnClick method which will fire the click event handlers.

I feel dirty posting this but it works...

MethodInfo clickMethodInfo = typeof(Button).GetMethod("OnClick", BindingFlags.NonPublic | BindingFlags.Instance);

clickMethodInfo.Invoke(buttonToInvoke, new object[] { EventArgs.Empty });

How to pass complex object to ASP.NET WebApi GET from jQuery ajax call?

If you append json data to query string, and parse it later in web api side. you can parse complex object. It's useful rather than post json object style. This is my solution.

//javascript file 
var data = { UserID: "10", UserName: "Long", AppInstanceID: "100", ProcessGUID: "BF1CC2EB-D9BD-45FD-BF87-939DD8FF9071" };
var request = JSON.stringify(data);
request = encodeURIComponent(request);

doAjaxGet("/ProductWebApi/api/Workflow/StartProcess?data=", request, function (result) {
    window.console.log(result);
});

//webapi file:
[HttpGet]
public ResponseResult StartProcess()
{
    dynamic queryJson = ParseHttpGetJson(Request.RequestUri.Query);
        int appInstanceID = int.Parse(queryJson.AppInstanceID.Value);
    Guid processGUID = Guid.Parse(queryJson.ProcessGUID.Value);
    int userID = int.Parse(queryJson.UserID.Value);
    string userName = queryJson.UserName.Value;
}

//utility function:
public static dynamic ParseHttpGetJson(string query)
{
    if (!string.IsNullOrEmpty(query))
    {
        try
        {
            var json = query.Substring(7, query.Length - 7); //seperate ?data= characters
            json = System.Web.HttpUtility.UrlDecode(json);
            dynamic queryJson = JsonConvert.DeserializeObject<dynamic>(json);

            return queryJson;
        }
        catch (System.Exception e)
        {
            throw new ApplicationException("can't deserialize object as wrong string content!", e);
        }
    }
    else
    {
        return null;
    }
}

Creating Scheduled Tasks

You can use Task Scheduler Managed Wrapper:

using System;
using Microsoft.Win32.TaskScheduler;

class Program
{
   static void Main(string[] args)
   {
      // Get the service on the local machine
      using (TaskService ts = new TaskService())
      {
         // Create a new task definition and assign properties
         TaskDefinition td = ts.NewTask();
         td.RegistrationInfo.Description = "Does something";

         // Create a trigger that will fire the task at this time every other day
         td.Triggers.Add(new DailyTrigger { DaysInterval = 2 });

         // Create an action that will launch Notepad whenever the trigger fires
         td.Actions.Add(new ExecAction("notepad.exe", "c:\\test.log", null));

         // Register the task in the root folder
         ts.RootFolder.RegisterTaskDefinition(@"Test", td);

         // Remove the task we just created
         ts.RootFolder.DeleteTask("Test");
      }
   }
}

Alternatively you can use native API or go for Quartz.NET. See this for details.

REST - HTTP Post Multipart with JSON

If I understand you correctly, you want to compose a multipart request manually from an HTTP/REST console. The multipart format is simple; a brief introduction can be found in the HTML 4.01 spec. You need to come up with a boundary, which is a string not found in the content, let’s say HereGoes. You set request header Content-Type: multipart/form-data; boundary=HereGoes. Then this should be a valid request body:

--HereGoes
Content-Disposition: form-data; name="myJsonString"
Content-Type: application/json

{"foo": "bar"}
--HereGoes
Content-Disposition: form-data; name="photo"
Content-Type: image/jpeg
Content-Transfer-Encoding: base64

<...JPEG content in base64...>
--HereGoes--

Print all key/value pairs in a Java ConcurrentHashMap

The HashMap has forEach as part of its structure. You can use that with a lambda expression to print out the contents in a one liner such as:

map.forEach((k,v)-> System.out.println(k+", "+v));

or

map.forEach((k,v)-> System.out.println("key: "+k+", value: "+v));

RegEx match open tags except XHTML self-contained tags

Here is a PHP based parser that parses HTML using some ungodly regex. As the author of this project, I can tell you it is possible to parse HTML with regex, but not efficient. If you need a server-side solution (as I did for my wp-Typography WordPress plugin), this works.

download csv file from web api in angular js

None of those worked for me in Chrome 42...

Instead my directive now uses this link function (base64 made it work):

  link: function(scope, element, attrs) {
    var downloadFile = function downloadFile() {
      var filename = scope.getFilename();
      var link = angular.element('<a/>');
      link.attr({
        href: 'data:attachment/csv;base64,' + encodeURI($window.btoa(scope.csv)),
        target: '_blank',
        download: filename
      })[0].click();
      $timeout(function(){
        link.remove();
      }, 50);
    };

    element.bind('click', function(e) {
      scope.buildCSV().then(function(csv) {
        downloadFile();
      });
      scope.$apply();
    });
  }

how to check for datatype in node js- specifically for integer

_x000D_
_x000D_
var val = ... //the value you want to check_x000D_
if(Number.isNaN(Number(val))){_x000D_
  console.log("This is NOT a number!");_x000D_
}else{_x000D_
  console.log("This IS a number!");_x000D_
}
_x000D_
_x000D_
_x000D_

"unrecognized selector sent to instance" error in Objective-C

How to debug ‘unrecognized selector send to instance’

In most of the cases Xcode do not take us to the exact line where this issue happen. When app crash you won’t see the line of code that caused this rather you will be taken to App delegate class, with error output something following:

[UITableViewCellContentView image]: unrecognized selector sent to instance

or

[__NSDictionaryI objectAtIndex:] unrecognized selector sent to instance

or

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[TestApp.MyViewController viewDidLoad:]: unrecognized selector sent to instance 0xDABCDD'

How to find line of code causing this:

Go to breakpoint navigator. Click ‘+’ option. click ‘Exception Breakpoint’. An new widget like following will apear.

enter image description here

Add following condition block:

-[NSObject(NSObject) doesNotRecognizeSelector:]

enter image description here

You can also put breakpoint for all exception. Now run your code again. this time, breakpoint will trigger when this exception occurs.

WRITTEN BY: Prafulla Singh

Full explanition: https://prafullkumar77.medium.com/how-to-debug-unrecognized-selector-send-to-instance-402473bc23d

Launch an app on OS X with command line

An application bundle (a .app file) is actually a bunch of directories. Instead of using open and the .app name, you can actually move in to it and start the actual binary. For instance:

$ cd /Applications/LittleSnapper.app/
$ ls
Contents
$ cd Contents/MacOS/
$ ./LittleSnapper

That is the actual binary that might accept arguments (or not, in LittleSnapper's case).

How to get the size of a varchar[n] field in one SQL statement?

For SQL Server (2008 and above):

SELECT COLUMNPROPERTY(OBJECT_ID('mytable'), 'Remarks', 'PRECISION');

COLUMNPROPERTY returns information for a column or parameter (id, column/parameter, property). The PRECISION property returns the length of the data type of the column or parameter.

COLUMNPROPERTY documentation

How to select between brackets (or quotes or ...) in Vim?

For selecting within single quotes use vi'.

For selecting within parenthesis use vi(.

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

What's the difference between django OneToOneField and ForeignKey?

OneToOneField (one-to-one) realizes, in object orientation, the notion of composition, while ForeignKey (one-to-many) relates to agregation.

Hibernate - Batch update returned unexpected row count from update: 0 actual row count: 0 expected: 1

I got the same message. After looking for a code related source it got to me that running the application on a local machine interferes with the dev stage, because the share the same DB. So sometimes one server has deleted an entry already while the other just wanted to do the same.

flutter remove back button on appbar

  appBar: new AppBar(title: new Text("SmartDocs SPAY"),backgroundColor: Colors.blueAccent, automaticallyImplyLeading:false,
        leading: new Container(),
      ),

It is working Fine

How to reset par(mfrow) in R

You can reset the plot by doing this:

dev.off()

HTML input time in 24 format

You can't do it with the HTML5 input type. There are many libs available to do it, you can use momentjs or some other jQuery UI components for the best outcome.

resize font to fit in a div (on one line)

CSS no, Javascript yes

There's no way you could do this using CSS, but you can do it in javascript/jQuery. To help you with your pseudo code because you already know what to do. It's just that you don't know how to detect excess width.

The best way would be to have a DIV with following (at least) style:

position: absolute;
visibility: hidden;
white-space: nowrap;
font-family: /* same as your title's */

then copy your text to it and set some starting font size. Then you can iterate through your while loop and stop when div's width is appropriate. Then set calculated font size to your original title.

This way this checking will be hidden from user's eyes and it will therefore work faster as well.

BTW: This is the usual way how auto growing textarea scripts work. They use dummy divs with same style settings as the original text area and adjust area's height as the user types in text. So Text area can be quite small at first but if user types in lots of text it will auto grow to accommodate content.

While loop optimization

You could optimize your while loop to decrease the number of iterations considerably by doing this:

  1. Set a starting font size.
  2. get test DIV's width.
  3. calculate width factor between orig_div and test_div.
  4. adjust font size by this factor rather than increase/decrease by one unit
  5. test test_div width

How to unpack and pack pkg file?

In addition to what @abarnert said, I today had to find out that the default cpio utility on Mountain Lion uses a different archive format per default (not sure which), even with the man page stating it would use the old cpio/odc format. So, if anyone stumbles upon the cpio read error: bad file format message while trying to install his/her manipulated packages, be sure to include the format in the re-pack step:

find ./Foo.app | cpio -o --format odc | gzip -c > Payload

Height of an HTML select box (dropdown)

You can change the height of one. Don't use height="500"(Just an example number). Use the style. You can use <style>tag or just use this:

<!DOCTYPE html>
<html>
<body>
  <select id="option" style="height: 100px;">
    <option value="1">Option 1
    <option value="2">Option 2
  </select>
</body>
</html>

I spotlight the change:

  <select id="option" style="height: 100px;">

And even better...

style="height: 100px;">

You see that?

Please up vote if it's helpful!

How to add anchor tags dynamically to a div in Javascript?

here's a pure Javascript alternative:

var mydiv = document.getElementById("myDiv");
var aTag = document.createElement('a');
aTag.setAttribute('href',"yourlink.htm");
aTag.innerText = "link text";
mydiv.appendChild(aTag);

Change background color for selected ListBox item

I've tried various solutions and none worked for me, after some more research I've found a solution that worked for me here

https://gist.github.com/LGM-AdrianHum/c8cb125bc493c1ccac99b4098c7eeb60

   <Style x:Key="_ListBoxItemStyle" TargetType="ListBoxItem">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="ListBoxItem">
                        <Border Name="_Border"
                                Padding="2"
                                SnapsToDevicePixels="true">
                            <ContentPresenter />
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsSelected" Value="true">
                                <Setter TargetName="_Border" Property="Background" Value="Yellow"/>
                                <Setter Property="Foreground" Value="Red"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>

 <ListBox ItemContainerStyle="{DynamicResource _ListBoxItemStyle}"
                 Width="200" Height="250"
                 ScrollViewer.VerticalScrollBarVisibility="Auto"
                 ScrollViewer.HorizontalScrollBarVisibility="Auto">
            <ListBoxItem>Hello</ListBoxItem>
            <ListBoxItem>Hi</ListBoxItem>
        </ListBox>

I posted it here, as this is the first google result for this problem so some others may find it useful.

PHP Warning: Module already loaded in Unknown on line 0

You should have a /etc/php2/conf.d directory (At least on Ubuntu I do) containing a bunch of .ini files which all get loaded when php runs. These files can contain duplicate settings that conflict with settings in php.ini. In my PHP installation I notice a file conf.d/20-intl.ini with an extension=intl.so setting. I bet that's your conflict.

MySql: is it possible to 'SUM IF' or to 'COUNT IF'?

You can use a CASE statement:

SELECT count(id), 
    SUM(hour) as totHour, 
    SUM(case when kind = 1 then 1 else 0 end) as countKindOne

How to embed fonts in HTML?

I asked this a while back. The answer is basically that it doesn't work. :(

Char array in a struct - incompatible assignment?

This has nothing to do with structs - arrays in C are not assignable:

char a[20];
a = "foo";   // error

you need to use strcpy:

strcpy( a, "foo" );

or in your code:

strcpy( sara.first, "Sara" );

How do I add an element to a list in Groovy?

From the documentation:

We can add to a list in many ways:

assert [1,2] + 3 + [4,5] + 6 == [1, 2, 3, 4, 5, 6]
assert [1,2].plus(3).plus([4,5]).plus(6) == [1, 2, 3, 4, 5, 6]
    //equivalent method for +
def a= [1,2,3]; a += 4; a += [5,6]; assert a == [1,2,3,4,5,6]
assert [1, *[222, 333], 456] == [1, 222, 333, 456]
assert [ *[1,2,3] ] == [1,2,3]
assert [ 1, [2,3,[4,5],6], 7, [8,9] ].flatten() == [1, 2, 3, 4, 5, 6, 7, 8, 9]

def list= [1,2]
list.add(3) //alternative method name
list.addAll([5,4]) //alternative method name
assert list == [1,2,3,5,4]

list= [1,2]
list.add(1,3) //add 3 just before index 1
assert list == [1,3,2]
list.addAll(2,[5,4]) //add [5,4] just before index 2
assert list == [1,3,5,4,2]

list = ['a', 'b', 'z', 'e', 'u', 'v', 'g']
list[8] = 'x'
assert list == ['a', 'b', 'z', 'e', 'u', 'v', 'g', null, 'x']

You can also do:

def myNewList = myList << "fifth"

Python - use list as function parameters

This has already been answered perfectly, but since I just came to this page and did not understand immediately I am just going to add a simple but complete example.

def some_func(a_char, a_float, a_something):
    print a_char

params = ['a', 3.4, None]
some_func(*params)

>> a

How do I create a MongoDB dump of my database?

take mongodb backup for particular db and delete 7 days old backup using bin sh command :-

#!/bin/bash

MONGO_DATABASE="nexgtv_16"
APP_NAME="test"
MONGO_HOST="127.0.0.1"
MONGO_PORT="27017"
TIMESTAMP=`date +%F-%H%M`
MONGODUMP_PATH="/usr/bin/mongodump"
BACKUPS_DIR="/home/mongodbbackups/backups/$APP_NAME"
BACKUP_NAME="$APP_NAME-$TIMESTAMP"
$MONGODUMP_PATH -d $MONGO_DATABASE
mkdir -p $BACKUPS_DIR
mv dump $BACKUP_NAME
tar -zcvf $BACKUPS_DIR/$BACKUP_NAME.tgz $BACKUP_NAME
rm -rf $BACKUP_NAME
find /home/mongodbbackups/backups/test/ -mindepth 1 -mtime +7 -delete

align images side by side in html

I suggest to use a container for each img p like this:

<div class="image123">
    <div style="float:left;margin-right:5px;">
        <img src="/images/tv.gif" height="200" width="200"  />
        <p style="text-align:center;">This is image 1</p>
    </div>
    <div style="float:left;margin-right:5px;">
        <img class="middle-img" src="/images/tv.gif/" height="200" width="200" />
        <p style="text-align:center;">This is image 2</p>
    </div>
    <div style="float:left;margin-right:5px;">
        <img src="/images/tv.gif/" height="200" width="200" />
        <p style="text-align:center;">This is image 3</p>
    </div>
</div>

Then apply float:left to each container. I add and 5px margin right so there is a space between each image. Also alway close your elements. Maybe in html img tag is not important to close but in XHTML is.

fiddle

Also a friendly advice. Try to avoid inline styles as much as possible. Take a look here:

html

<div class="image123">
    <div>
        <img src="/images/tv.gif" />
        <p>This is image 1</p>
    </div>
    <div>
        <img class="middle-img" src="/images/tv.gif/" />
        <p>This is image 2</p>
    </div>
    <div>
        <img src="/images/tv.gif/" />
        <p>This is image 3</p>
    </div>
</div>

css

div{
    float:left;
    margin-right:5px;
}

div > img{
   height:200px;
    width:200px;
}

p{
    text-align:center;
}

It's generally recommended that you use linked style sheets because:

  • They can be cached by browsers for performance
  • Generally a lot easier to maintain for a development perspective

source

fiddle

Javascript Array of Functions

Ah man there are so many weird answers...

const execute = (fn) => fn()
const arrayOfFunctions = [fn1, fn2, fn3]

const results = arrayOfFunctions.map(execute)

or if you want to sequentially feed each functions result to the next:
compose(fn3, fn2, fn1)

compose is not supported by default, but there are libraries like ramda, lodash, or even redux which provide this tool

Check input value length

<input type='text' minlength=3 /><br />

if browser supports html5,

it will automatical be validate attributes(minlength) in tag

but Safari(iOS) doesn't working

How to keep Docker container running after starting services?

This is not really how you should design your Docker containers.

When designing a Docker container, you're supposed to build it such that there is only one process running (i.e. you should have one container for Nginx, and one for supervisord or the app it's running); additionally, that process should run in the foreground.

The container will "exit" when the process itself exits (in your case, that process is your bash script).


However, if you really need (or want) to run multiple service in your Docker container, consider starting from "Docker Base Image", which uses runit as a pseudo-init process (runit will stay online while Nginx and Supervisor run), which will stay in the foreground while your other processes do their thing.

They have substantial docs, so you should be able to achieve what you're trying to do reasonably easily.

Using TortoiseSVN how do I merge changes from the trunk to a branch and vice versa?

You should use "merge a range of revision".

To merge changes from the trunk to a branch, inside the branch working copy choose "merge range of revisions" and enter the trunk URL and the start and end revisions to merge.

The same in the opposite way to merge a branch in the trunk.

About the --reintegrate flag, check the manual here: http://tortoisesvn.net/docs/release/TortoiseSVN_en/tsvn-dug-merge.html#tsvn-dug-merge-reintegrate

OS X Terminal Colors

When I worked on Mac OS X in the lab I was able to get the terminal colors from using Terminal (rather than X11) and then editing the profile (from the Mac menu bar). The interface is a bit odd on the colors, but you have to set the modified theme as default.

Further settings worked by editing .bashrc.

Deploy a project using Git push

Given an environment where you have multiple developers accessing the same repository the following guidelines may help.

Ensure that you have a unix group that all devs belong to and give ownership of the .git repository to that group.

  1. In the .git/config of the server repository set sharedrepository = true. (This tells git to allow multiple users which is needed for commits and deployment.

  2. set the umask of each user in their bashrc files to be the same - 002 is a good start

How to write inline if statement for print?

If you don't want to from __future__ import print_function you can do the following:

a = 100
b = True
print a if b else "",  # Note the comma!
print "see no new line"

Which prints:

100 see no new line

If you're not aversed to from __future__ import print_function or are using python 3 or later:

from __future__ import print_function
a = False
b = 100
print(b if a else "", end = "")

Adding the else is the only change you need to make to make your code syntactically correct, you need the else for the conditional expression (the "in line if else blocks")

The reason I didn't use None or 0 like others in the thread have used, is because using None/0 would cause the program to print None or print 0 in the cases where b is False.

If you want to read about this topic I've included a link to the release notes for the patch that this feature was added to Python.

The 'pattern' above is very similar to the pattern shown in PEP 308:

This syntax may seem strange and backwards; why does the condition go in the middle of the expression, and not in the front as in C's c ? x : y? The decision was checked by applying the new syntax to the modules in the standard library and seeing how the resulting code read. In many cases where a conditional expression is used, one value seems to be the 'common case' and one value is an 'exceptional case', used only on rarer occasions when the condition isn't met. The conditional syntax makes this pattern a bit more obvious:

contents = ((doc + '\n') if doc else '')

So I think overall this is a reasonable way of approching it but you can't argue with the simplicity of:

if logging: print data

maven compilation failure

I had the same problem and this is how I suggest you fix it:

Run:

mvn dependency:list

and read carefully if there are any warning messages indicating that for some dependencies there will be no transitive dependencies available.

If yes, re-run it with -X flag:

mvn dependency:list -X

to see detailed info what is maven complaining about (there might be a lot of output for -X flag)

In my case there was a problem in dependent maven module pom.xml - with managed dependency. Although there was a version for the managed dependency defined in parent pom, Maven was unable to resolve it and was complaining about missing version in the dependent pom.xml

So I just configured the missing version and the problem disappeared.

Make index.html default, but allow index.php to be visited if typed in

I agree with @TheAlpha's accepted answer, Apache reads the DirectoryIndex target files from left to right , if the first file exists ,apche serves it and if it doesnt then the next file is served as an index for the directory. So if you have the following Directive :

DirectoryIndex file1.html file2.html

Apache will serve /file.html as index ,You will need to change the order of files if you want to set /file2.html as index

DirectoryIndex file2.html file1.html

You can also set index file using a RewriteRule

RewriteEngine on

RewriteRule ^$ /index.html [L]

RewriteRule above will rewrite your homepage to /index.html the rewriting happens internally so http://example.com/ would show you the contents ofindex.html .

How to retrieve the current value of an oracle sequence without increment it?

The follows is often used:

select field_SQ.nextval from dual;
select field_SQ.currval from DUAL;

However the following is able to change the sequence to what you expected. The 1 can be an integer (negative or positive)

alter sequence field_SQ increment by 1 minvalue 0

What is the advantage of using REST instead of non-REST HTTP?

@Timmmm, about your edit :

GET /timeline_posts     // could return the N first posts, with links to fetch the next/previous N posts

This would dramatically reduce the number of calls

And nothing prevents you from designing a server that accepts HTTP parameters to denote the field values your clients may want...

But this is a detail.

Much more important is the fact that you did not mention huge advantages of the REST architectural style (much better scalability, due to server statelessness; much better availability, due to server statelessness also; much better use of the standard services, such as caching for instance, when using a REST architectural style; much lower coupling between client and server, due to the use of a uniform interface; etc. etc.)

As for your remark

"Not all actions easily map to CRUD (create, read/retrieve, update, delete)."

: an RDBMS uses a CRUD approach, too (SELECT/INSERT/DELETE/UPDATE), and there is always a way to represent and act upon a data model.

Regarding your sentence

"You may not even be dealing with object type resources"

: a RESTful design is, by essence, a simple design - but this does NOT mean that designing it is simple. Do you see the difference ? You'll have to think a lot about the concepts your application will represent and handle, what must be done by it, if you prefer, in order to represent this by means of resources. But if you do so, you will end up with a more simple and efficient design.

Angular expression if array contains

You shouldn't overload the templates with complex logic, it's a bad practice. Remember to always keep it simple!

The better approach would be to extract this logic into reusable function on your $rootScope:

.run(function ($rootScope) {
  $rootScope.inArray = function (item, array) {
    return (-1 !== array.indexOf(item));
  };
})

Then, use it in your template:

<li ng-class="{approved: inArray(jobSet, selectedForApproval)}"></li>

I think everyone will agree that this example is much more readable and maintainable.

How to disable spring security for particular url

<http pattern="/resources/**" security="none"/>

Or with Java configuration:

web.ignoring().antMatchers("/resources/**");

Instead of the old:

 <intercept-url pattern="/resources/**" filters="none"/>

for exp . disable security for a login page :

  <intercept-url pattern="/login*" filters="none" />

Importing CSV with line breaks in Excel 2007

If anyone stumbling across this thread and is looking for a definitive answer here goes (credit to the person mentioning LibreOffice:

1) Install LibreOffice 2) Open Calc and import file 3) My txt file had the fields separated by , and character fields enclosed in " 4) save as ODS file 5) Open ODS file in Excel 6) Save as .xls(x) 7) Done. 8) This worked perfectly for me and saved me BIGTIME!

Postgres: INSERT if does not exist already

The solution in simple, but not immediatly.
If you want use this instruction, you must make one change to the db:

ALTER USER user SET search_path to 'name_of_schema';

after these changes "INSERT" will work correctly.

How can I convert a DateTime to an int?

string date = DateTime.Now.ToString();

date = date.Replace("/", "");
date = date.Replace(":", "");
date = date.Replace(" ", "");
date = date.Replace("AM", "");
date = date.Replace("PM", "");            
return date;

How to download dependencies in gradle

For Intellij go to View > Tool Windows > Gradle > Refresh All Projects (the blue circular arrows at the top of the Gradle window. enter image description here

How to implement common bash idioms in Python?

Your best bet is a tool that is specifically geared towards your problem. If it's processing text files, then Sed, Awk and Perl are the top contenders. Python is a general-purpose dynamic language. As with any general purpose language, there's support for file-manipulation, but that isn't what it's core purpose is. I would consider Python or Ruby if I had a requirement for a dynamic language in particular.

In short, learn Sed and Awk really well, plus all the other goodies that come with your flavour of *nix (All the Bash built-ins, grep, tr and so forth). If it's text file processing you're interested in, you're already using the right stuff.

How to acces external json file objects in vue.js app

If your file looks like this:

[
    {
        "firstname": "toto",
        "lastname": "titi"
    },
    {
        "firstname": "toto2",
        "lastname": "titi2"
    },
]

You can do:

import json from './json/data.json';
// ....
json.forEach(x => { console.log(x.firstname, x.lastname); });

What are public, private and protected in object oriented programming?

as above, but qualitatively:

private - least access, best encapsulation
protected - some access, moderate encapsulation
public - full access, no encapsulation

the less access you provide the fewer implementation details leak out of your objects. less of this sort of leakage means more flexibility (aka "looser coupling") in terms of changing how an object is implemented without breaking clients of the object. this is a truly fundamental thing to understand.

Remove shadow below actionbar

For Android 5.0, if you want to set it directly into a style use:

<item name="android:elevation">0dp</item>

and for Support library compatibility use:

<item name="elevation">0dp</item>

Example of style for a AppCompat light theme:

<style name="Theme.MyApp.ActionBar" parent="@style/Widget.AppCompat.Light.ActionBar.Solid.Inverse">
    <!-- remove shadow below action bar -->
    <!-- <item name="android:elevation">0dp</item> -->
    <!-- Support library compatibility -->
    <item name="elevation">0dp</item>
</style>

Then apply this custom ActionBar style to you app theme:

<style name="Theme.MyApp" parent="Theme.AppCompat.Light">
    <item name="actionBarStyle">@style/Theme.MyApp.ActionBar</item>
</style>

For pre 5.0 Android, add this too to your app theme:

<!-- Remove shadow below action bar Android < 5.0 -->
<item name="android:windowContentOverlay">@null</item>

Find nginx version?

Try running command 'whereis nginx'. It will give you the correct path of the nginx installation, in my case nginx is installed in '/usr/local/sbin', so I need to check if this path exists in output of command 'echo $PATH'. If you don't find the path in the output of this command, then you can add this.

Suppose the output of my 'echo $PATH' command is this:

  ~$ echo $PATH
/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin:/usr/local/nginx/sbin

Then I can append the path '/usr/local/sbin' in $PATH by following command:

~$ echo 'export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin:/usr/local/nginx/sbin"' >> $HOME/.bashrc

Please check your nginx installation path may differ from mine, but the steps for adding them are same.

What is the best way to convert seconds into (Hour:Minutes:Seconds:Milliseconds) time?

I'd suggest you use the TimeSpan class for this.

public static void Main(string[] args)
{
    TimeSpan t = TimeSpan.FromSeconds(80);
    Console.WriteLine(t.ToString());

    t = TimeSpan.FromSeconds(868693412);
    Console.WriteLine(t.ToString());
}

Outputs:

00:01:20
10054.07:43:32

Fatal error: Class 'ZipArchive' not found in

For CentOS based server use

yum install php-pecl-zip.x86_64

Enable it by running: echo "extension=zip.so" >> /etc/php.d/zip.ini

Mark error in form using Bootstrap

Bootstrap V3:

Once i was searching for laravel features then i got to know this amazing form validation. Later on, i amended glyphicon icon features. Now, it looks great.

<div class="col-md-12">
<div class="form-group has-error has-feedback">
    <input id="enter email" name="email" type="text" placeholder="Enter email" class="form-control ">
    <span class="glyphicon glyphicon-remove form-control-feedback"></span>       
    <span class="help-block"><p>The Email field is required.</p></span>                                        
</div>
</div>
<div class="clearfix"></div>

<div class="col-md-6">
<div class="form-group has-error has-feedback">
    <input id="account_holder_name" name="name" type="text" placeholder="Name" class="form-control ">
    <span class="glyphicon glyphicon-remove form-control-feedback"></span>                                            
    <span class="help-block"><p>The Name field is required.</p></span>                                        
</div>
</div>
<div class="col-md-6">
<div class="form-group has-error has-feedback">
 <input id="check_np" name="check_no" type="text" placeholder="Check no" class="form-control ">
 <span class="glyphicon glyphicon-remove form-control-feedback"></span>
<span class="help-block"><p>The Check No. field is required.</p></span>                                       
</div>
</div>

This is what it looks like: enter image description here

Once i completed it i thought i should implement it in Codeigniter as well. So here is the Codeigniter-3 validation with Bootstrap:

Controller

function addData()
{
$this->load->library('form_validation');
$this->form_validation->set_rules('email','Email','trim|required|valid_email|max_length[128]');
if($this->form_validation->run() == FALSE)
{
//validation fails. Load your view.
$this->loadViews('Load your view','pass your data to view if any');
}
else
{  
 //validation pass. Your code here.
}
}

View

<div class="col-md-12">
<?php 
 $email_error = (form_error('email') ? 'has-error has-feedback' : '');
 if(!empty($email_error)){
 $emailData = '<span class="help-block">'.form_error('email').'</span>';
 $emailClass = $email_error;
 $emailIcon = '<span class="glyphicon glyphicon-remove form-control-feedback"></span>';
}
else{
    $emailClass = $emailIcon = $emailData = '';
 } 
 ?>
<div class="form-group <?= $emailClass ?>">
<input id="enter email" name="email" type="text" placeholder="Enter email" class="form-control ">
<?= $emailIcon ?>
<?= $emailData ?>
</div>
</div>

Output: enter image description here

Imported a csv-dataset to R but the values becomes factors

By default, read.csv checks the first few rows of your data to see whether to treat each variable as numeric. If it finds non-numeric values, it assumes the variable is character data, and character variables are converted to factors.

It looks like the PTS and MP variables in your dataset contain non-numerics, which is why you're getting unexpected results. You can force these variables to numeric with

point <- as.numeric(as.character(point))
time <- as.numeric(as.character(time))

But any values that can't be converted will become missing. (The R FAQ gives a slightly different method for factor -> numeric conversion but I can never remember what it is.)

Java check to see if a variable has been initialized

Assuming you're interested in whether the variable has been explicitly assigned a value or not, the answer is "not really". There's absolutely no difference between a field (instance variable or class variable) which hasn't been explicitly assigned at all yet, and one which has been assigned its default value - 0, false, null etc.

Now if you know that once assigned, the value will never reassigned a value of null, you can use:

if (box != null) {
    box.removeFromCanvas();
}

(and that also avoids a possible NullPointerException) but you need to be aware that "a field with a value of null" isn't the same as "a field which hasn't been explicitly assigned a value". Null is a perfectly valid variable value (for non-primitive variables, of course). Indeed, you may even want to change the above code to:

if (box != null) {
    box.removeFromCanvas();
    // Forget about the box - we don't want to try to remove it again
    box = null;
}

The difference is also visible for local variables, which can't be read before they've been "definitely assigned" - but one of the values which they can be definitely assigned is null (for reference type variables):

// Won't compile
String x;
System.out.println(x);

// Will compile, prints null
String y = null;
System.out.println(y);

Writing file to web server - ASP.NET

protected void TestSubmit_ServerClick(object sender, EventArgs e)
{
  using (StreamWriter _testData = new StreamWriter(Server.MapPath("~/data.txt"), true))
 {
  _testData.WriteLine(TextBox1.Text); // Write the file.
 }         
}

Server.MapPath takes a virtual path and returns an absolute one. "~" is used to resolve to the application root.

Make div scrollable

You need to remove the

min-height:440px;

to

height:440px;

and then add

overflow: auto;

property to the class of the required div

How to position the form in the center screen?

Try using this:

this.setBounds(x,y,w,h);

How to convert string to boolean in typescript Angular 4

In your scenario, converting a string to a boolean can be done via something like someString === 'true' (as was already answered).

However, let me try to address your main issue: dealing with the local storage.

The local storage only supports strings as values; a good way of using it would thus be to always serialise your data as a string before storing it in the storage, and reversing the process when fetching it.

A possibly decent format for serialising your data in is JSON, since it is very easy to deal with in JavaScript.

The following functions could thus be used to interact with local storage, provided that your data can be serialised into JSON.

function setItemInStorage(key, item) {
  localStorage.setItem(key, JSON.stringify(item));
}

function getItemFromStorage(key) {
  return JSON.parse(localStorage.getItem(key));
}

Your example could then be rewritten as:

setItemInStorage('CheckOutPageReload', [this.btnLoginNumOne, this.btnLoginEdit]);

And:

if (getItemFromStorage('CheckOutPageReload')) {
  const pageLoadParams = getItemFromStorage('CheckOutPageReload');
  this.btnLoginNumOne = pageLoadParams[0];
  this.btnLoginEdit = pageLoadParams[1];
}

Selecting text in an element (akin to highlighting with your mouse)

Here's a version with no browser sniffing and no reliance on jQuery:

function selectElementText(el, win) {
    win = win || window;
    var doc = win.document, sel, range;
    if (win.getSelection && doc.createRange) {
        sel = win.getSelection();
        range = doc.createRange();
        range.selectNodeContents(el);
        sel.removeAllRanges();
        sel.addRange(range);
    } else if (doc.body.createTextRange) {
        range = doc.body.createTextRange();
        range.moveToElementText(el);
        range.select();
    }
}

selectElementText(document.getElementById("someElement"));
selectElementText(elementInIframe, iframe.contentWindow);

how to get yesterday's date in C#

string result = DateTime.Now.Date.AddDays(-1).ToString("yyyy-MM-dd");

Converting String To Float in C#

You can use parsing with double instead of float to get more precision value.

Change User Agent in UIWebView

The only problem I have found was change user agent only

- (BOOL)application:(UIApplication *)application
        didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    NSDictionary *dictionary = [NSDictionary 
        dictionaryWithObjectsAndKeys:
        @"Mozilla/5.0 (iPod; U; CPU iPhone OS 4_3_3 like Mac OS X; ja-jp) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8J2 Safari/6533.18.5", 
        @"UserAgent", nil];
    [[NSUserDefaults standardUserDefaults] registerDefaults:dictionary];
}

jQuery - get all divs inside a div with class ".container"

To get all divs under 'container', use the following:

$(".container>div")  //or
$(".container").children("div");

You can stipulate a specific #id instead of div to get a particular one.

You say you want a div with an 'undefined' id. if I understand you right, the following would achieve this:

$(".container>div[id=]")

jquery if div id has children

There's actually quite a simple native method for this:

if( $('#myfav')[0].hasChildNodes() ) { ... }

Note that this also includes simple text nodes, so it will be true for a <div>text</div>.

A required class was missing while executing org.apache.maven.plugins:maven-war-plugin:2.1.1:war

Does the class org.apache.maven.shared.filtering.MavenFilteringException exist in file:/C:/Users/utopcu/.m2/repository/org/apache/maven/shared/maven-filtering/1.0-beta-2/maven-filtering-1.0-beta-2.jar?

The error message suggests that it doesn't. Maybe the JAR was corrupted somehow.

I'm also wondering where the version 1.0-beta-2 comes from; I have 1.0 on my disk. Try version 2.3 of the WAR plugin.

How to refresh activity after changing language (Locale) inside application

For Android 4.2 (API 17), you need to use android:configChanges="locale|layoutDirection" in your AndroidManifest.xml. See onConfigurationchanged is not called over jellybean(4.2.1)

Style bottom Line in Android

I feel it is straightforward, without all this negative paddings or storks.

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:drawable="@color/main_bg_color"/>
    <item android:gravity="bottom">
        <shape android:shape="rectangle">
            <size android:height="5dp"/>
            <solid android:color="@color/bottom_bar_color"/>
        </shape>
    </item>
</layer-list>

How to create a Date in SQL Server given the Day, Month and Year as Integers

So, you can try this solution:

DECLARE @DAY INT = 25
DECLARE @MONTH INT  = 10 
DECLARE @YEAR INT = 2016
DECLARE @DATE AS DATETIME

SET @DATE = CAST(RTRIM(@YEAR * 10000 + @MONTH * 100 + @DAY) AS DATETIME) 

SELECT REPLACE(CONVERT(VARCHAR(10), @DATE, 102), '.', '-') AS EXPECTDATE

Or you can try this a few lines of code:

DECLARE @DAY INT = 25
DECLARE @MONTH INT  = 10 
DECLARE @YEAR INT = 2016

SELECT CAST(RTRIM(@YEAR * 10000 +'-' +  @MONTH * 100+ '-' + @DAY) AS DATE) AS EXPECTDATE

How can I pretty-print JSON in a shell script?

I know that the original post asked for a shell script, but there are so many useful and irrelevant answers that probably did not help the original author. Adding on to irrelevance :)

BTW I could not get any command line tools to work.

If somebody want simple JSON JavaScript code, they could do:

JSON.stringfy(JSON.parse(str), null, 4)

http://www.geospaces.org/geoweb/Wiki.jsp?page=JSON%20Utilities%20Demos

Here is JavaScript code that not only pretties the JSON, but orders them by their attribute or by attribute and level.

If input is

{ "c": 1, "a": {"b1": 2, "a1":1 }, "b": 1},

it either prints (groups all the objects together):

{
     "b": 1,
     "c": 1,
     "a": {
          "a1": 1,
          "b1": 2
     }
}

OR (just orders by key):

{
 "a": {
      "a1": 1,
      "b1": 2
 },
 "b": 1,
 "c": 1
}

Fatal error: Maximum execution time of 30 seconds exceeded

if all the above didn't work for you then add an .htaccess file to the directory where your script is located and put this inside

<IfModule mod_php5.c>
php_value post_max_size 200M
php_value upload_max_filesize 200M
php_value memory_limit 300M
php_value max_execution_time 259200
php_value max_input_time 259200
php_value session.gc_maxlifetime 1200
</IfModule>

this was the way I solved my problem , neither ini_set('max_execution_time', 86400); nor set_time_limit(86400) solved my problem , but the .htaccess method did.

What does it mean "No Launcher activity found!"

If you are using the standard eclipse IDE provided by google for Android development, you can check the "Launcher Activity" check-box while creating a new Activity. Please find below:

enter image description here

How to suppress "error TS2533: Object is possibly 'null' or 'undefined'"?

This solution worked for me:

  • go to tsconfig.json and add "strictNullChecks":false

enter image description here

gnuplot plotting multiple line graphs

Whatever your separator is in your ls.dat, you can specify it to gnuplot:

set datafile separator "\t"

Unable to call the built in mb_internal_encoding method?

For Debian/Ubuntu:

sudo apt-get install php7.0-mbstring

Spring security CORS Filter

Since Spring Security 4.1, this is the proper way to make Spring Security support CORS (also needed in Spring Boot 1.4/1.5):

@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {

    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
                .allowedMethods("HEAD", "GET", "PUT", "POST", "DELETE", "PATCH");
    }
}

and:

@Configuration
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(HttpSecurity http) throws Exception {
//        http.csrf().disable();
        http.cors();
    }

    @Bean
    public CorsConfigurationSource corsConfigurationSource() {
        final CorsConfiguration configuration = new CorsConfiguration();
        configuration.setAllowedOrigins(ImmutableList.of("*"));
        configuration.setAllowedMethods(ImmutableList.of("HEAD",
                "GET", "POST", "PUT", "DELETE", "PATCH"));
        // setAllowCredentials(true) is important, otherwise:
        // The value of the 'Access-Control-Allow-Origin' header in the response must not be the wildcard '*' when the request's credentials mode is 'include'.
        configuration.setAllowCredentials(true);
        // setAllowedHeaders is important! Without it, OPTIONS preflight request
        // will fail with 403 Invalid CORS request
        configuration.setAllowedHeaders(ImmutableList.of("Authorization", "Cache-Control", "Content-Type"));
        final UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", configuration);
        return source;
    }
}

Do not do any of below, which are the wrong way to attempt solving the problem:

  • http.authorizeRequests().antMatchers(HttpMethod.OPTIONS, "/**").permitAll();
  • web.ignoring().antMatchers(HttpMethod.OPTIONS);

Reference: http://docs.spring.io/spring-security/site/docs/4.2.x/reference/html/cors.html

How do you join tables from two different SQL Server instances in one SQL query

The best way I can think of to accomplish this is via sp_addlinkedserver. You need to make sure that whatever account you use to add the link (via sp_addlinkedsrvlogin) has permissions to the table you're joining, but then once the link is established, you can call the server by name, i.e.:

SELECT *
FROM server1table
    INNER JOIN server2.database.dbo.server2table ON .....

Visual Studio Code - is there a Compare feature like that plugin for Notepad ++?

There is plugin called Partial Diff which helps to compare text selections within a file, across different files, or to the clipboard.

Jar mismatch! Fix your dependencies

In my case there was another directory within my workspace, having the same jar file as the one in my project. I hadn't created that directory or anything in it. It was created by Eclipse I believe. I just erased that directory and it just runs ok.

"The page has expired due to inactivity" - Laravel 5.5

I change permission to storage and error was gone. It seemed lack of permission was the issue.

sudo chmod -R 775 storage/

When to use: Java 8+ interface default method, vs. abstract method

Please think first of open/closed principle. The default methods in interfaces DO VIOLATE it. This is a bad feature in Java. It encourages bad design, bad architecture, low software quality. I would suggest to avoid using default methods completely.

Ask yourself a few questions: Why can't you put your methods to the abstract class? Would you need then more than one abstract class? Then think about what is your class responsible for. Are you sure all methods you are going to put to the single class really fulfill the same purpose? May be you will distinguish several purposes and will then split your class into several classes, for each purpose its own class.

How to parse a CSV in a Bash script?

I was looking for an elegant solution that support quoting and wouldn't require installing anything fancy on my VMware vMA appliance. Turns out this simple python script does the trick! (I named the script csv2tsv.py, since it converts CSV into tab-separated values - TSV)

#!/usr/bin/env python

import sys, csv

with sys.stdin as f:
    reader = csv.reader(f)
    for row in reader:
        for col in row:
            print col+'\t',
        print

Tab-separated values can be split easily with the cut command (no delimiter needs to be specified, tab is the default). Here's a sample usage/output:

> esxcli -h $VI_HOST --formatter=csv network vswitch standard list |csv2tsv.py|cut -f12
Uplinks
vmnic4,vmnic0,
vmnic5,vmnic1,
vmnic6,vmnic2,

In my scripts I'm actually going to parse tsv output line by line and use read or cut to get the fields I need.

Best way to load module/class from lib folder in Rails 3?

As of Rails 2.3.9, there is a setting in config/application.rb in which you can specify directories that contain files you want autoloaded.

From application.rb:

# Custom directories with classes and modules you want to be autoloadable.
# config.autoload_paths += %W(#{config.root}/extras)

How to make use of ng-if , ng-else in angularJS

There is no directive for ng-else

You can use ng-if to achieve if(){..} else{..} in angularJs.

For your current situation,

<div ng-if="data.id == 5">
<!-- If block -->
</div>
<div ng-if="data.id != 5">
<!-- Your Else Block -->
</div>

jQuery: find element by text

Rocket's answer doesn't work.

<div>hhhhhh
<div>This is a test</div>
<div>Another Div</div>
</div>

I simply modified his DEMO here and you can see the root DOM is selected.

$('div:contains("test"):last').css('background-color', 'red');

add ":last" selector in the code to fix this.

Callback functions in C++

There isn't an explicit concept of a callback function in C++. Callback mechanisms are often implemented via function pointers, functor objects, or callback objects. The programmers have to explicitly design and implement callback functionality.

Edit based on feedback:

In spite of the negative feedback this answer has received, it is not wrong. I'll try to do a better job of explaining where I'm coming from.

C and C++ have everything you need to implement callback functions. The most common and trivial way to implement a callback function is to pass a function pointer as a function argument.

However, callback functions and function pointers are not synonymous. A function pointer is a language mechanism, while a callback function is a semantic concept. Function pointers are not the only way to implement a callback function - you can also use functors and even garden variety virtual functions. What makes a function call a callback is not the mechanism used to identify and call the function, but the context and semantics of the call. Saying something is a callback function implies a greater than normal separation between the calling function and the specific function being called, a looser conceptual coupling between the caller and the callee, with the caller having explicit control over what gets called. It is that fuzzy notion of looser conceptual coupling and caller-driven function selection that makes something a callback function, not the use of a function pointer.

For example, the .NET documentation for IFormatProvider says that "GetFormat is a callback method", even though it is just a run-of-the-mill interface method. I don't think anyone would argue that all virtual method calls are callback functions. What makes GetFormat a callback method is not the mechanics of how it is passed or invoked, but the semantics of the caller picking which object's GetFormat method will be called.

Some languages include features with explicit callback semantics, typically related to events and event handling. For example, C# has the event type with syntax and semantics explicitly designed around the concept of callbacks. Visual Basic has its Handles clause, which explicitly declares a method to be a callback function while abstracting away the concept of delegates or function pointers. In these cases, the semantic concept of a callback is integrated into the language itself.

C and C++, on the other hand, does not embed the semantic concept of callback functions nearly as explicitly. The mechanisms are there, the integrated semantics are not. You can implement callback functions just fine, but to get something more sophisticated which includes explicit callback semantics you have to build it on top of what C++ provides, such as what Qt did with their Signals and Slots.

In a nutshell, C++ has what you need to implement callbacks, often quite easily and trivially using function pointers. What it does not have is keywords and features whose semantics are specific to callbacks, such as raise, emit, Handles, event +=, etc. If you're coming from a language with those types of elements, the native callback support in C++ will feel neutered.

How do I correct this Illegal String Offset?

if ($inputs['type'] == 'attach') {

The code is valid, but it expects the function parameter $inputs to be an array. The "Illegal string offset" warning when using $inputs['type'] means that the function is being passed a string instead of an array. (And then since a string offset is a number, 'type' is not suitable.)

So in theory the problem lies elsewhere, with the caller of the code not providing a correct parameter.

However, this warning message is new to PHP 5.4. Old versions didn't warn if this happened. They would silently convert 'type' to 0, then try to get character 0 (the first character) of the string. So if this code was supposed to work, that's because abusing a string like this didn't cause any complaints on PHP 5.3 and below. (A lot of old PHP code has experienced this problem after upgrading.)

You might want to debug why the function is being given a string by examining the calling code, and find out what value it has by doing a var_dump($inputs); in the function. But if you just want to shut the warning up to make it behave like PHP 5.3, change the line to:

if (is_array($inputs) && $inputs['type'] == 'attach') {

Replace special characters in a string with _ (underscore)

string = string.replace(/[&\/\\#,+()$~%.'":*?<>{}]/g,'_');

Alternatively, to change all characters except numbers and letters, try:

string = string.replace(/[^a-zA-Z0-9]/g,'_');

How to split the screen with two equal LinearLayouts?

To Split a layout to equal parts

Use Layout Weights. Keep in mind that it is important to set layout_width as 0dp on children to make it work as intended.

on parent layout:

  1. Set weightSum of parent Layout as 1 (android:weightSum="1")

on the child layout:

  1. Set layout_width as 0dp (android:layout_width="0dp")
  2. Set layout_weight as 0.5 [half of weight sum fr equal two] (android:layout_weight="0.5")


To split layout to three equal parts:

  • parent: weightSum 3
  • child: layout_weight: 1

To split layout to four equal parts:

  • parent: weightSum 1
  • child: layout_weight: 0.25

To split layout to n equal parts:

  • parent: weightSum n
  • child: layout_weight: 1


Below is an example layout for splitting layout to two equal parts.

<LinearLayout
    android:id="@+id/layout_top"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:weightSum="1">

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="0.5"
        android:orientation="vertical">

        <TextView .. />

        <EditText .../>

    </LinearLayout>

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="0.5"
        android:orientation="vertical">

        <TextView ../>

        <EditText ../>

    </LinearLayout>

</LinearLayout>

Unsupported major.minor version 52.0 when rendering in Android Studio

For my case, my original Android SDK Build-tools version is 24 and Andoid SDK Tools version is 25.1.7. I install Android SDK Build-tools version 23.0.3 by Andoird SDK manager.

Modify these 2 lines to:

buildToolsVersion "23.0.3" compileSdkVersion 24

Then it works!

How to check if an array value exists?

<?php
if (in_array('your_variable', $Your_array)) {
    $redImg = 'true code here';
} else {
    $redImg = 'false code here';
} 
?>

PHP, get file name without file extension

If you don't know which extension you have, then you can try this:

$ext = strtolower(substr('yourFileName.ext', strrpos('yourFileName.ext', '.') + 1));
echo basename('yourFileName.ext','.'.$ext); // output: "youFileName" only

Working with all possibilities:

image.jpg // output: "image"
filename.image.png // output: "filename.image"
index.php // output: "index"

numpy get index where value is true

A simple and clean way: use np.argwhere to group the indices by element, rather than dimension as in np.nonzero(a) (i.e., np.argwhere returns a row for each non-zero element).

>>> a = np.arange(10)
>>> a
array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
>>> np.argwhere(a>4)
array([[5],
       [6],
       [7],
       [8],
       [9]])

np.argwhere(a) is the same as np.transpose(np.nonzero(a)).

Note: You cannot use a(np.argwhere(a>4)) to get the corresponding values in a. The recommended way is to use a[(a>4).astype(bool)] or a[(a>4) != 0] rather than a[np.nonzero(a>4)] as they handle 0-d arrays correctly. See the documentation for more details. As can be seen in the following example, a[(a>4).astype(bool)] and a[(a>4) != 0] can be simplified to a[a>4].

Another example:

>>> a = np.array([5,-15,-8,-5,10])
>>> a
array([  5, -15,  -8,  -5,  10])
>>> a > 4
array([ True, False, False, False,  True])
>>> a[a > 4]
array([ 5, 10])
>>> a = np.add.outer(a,a)
>>> a
array([[ 10, -10,  -3,   0,  15],
       [-10, -30, -23, -20,  -5],
       [ -3, -23, -16, -13,   2],
       [  0, -20, -13, -10,   5],
       [ 15,  -5,   2,   5,  20]])
>>> a = np.argwhere(a>4)
>>> a
array([[0, 0],
       [0, 4],
       [3, 4],
       [4, 0],
       [4, 3],
       [4, 4]])
>>> [print(i,j) for i,j in a]
0 0
0 4
3 4
4 0
4 3
4 4

PHPMailer AddAddress()

You need to call the AddAddress method once for every recipient. Like so:

$mail->AddAddress('[email protected]', 'Person One');
$mail->AddAddress('[email protected]', 'Person Two');
// ..

To make things easy, you should loop through an array to do this.

$recipients = array(
   '[email protected]' => 'Person One',
   '[email protected]' => 'Person Two',
   // ..
);
foreach($recipients as $email => $name)
{
   $mail->AddAddress($email, $name);
}

Better yet, add them as Carbon Copy recipients.

$mail->AddCC('[email protected]', 'Person One');
$mail->AddCC('[email protected]', 'Person Two');
// ..

To make things easy, you should loop through an array to do this.

$recipients = array(
   '[email protected]' => 'Person One',
   '[email protected]' => 'Person Two',
   // ..
);
foreach($recipients as $email => $name)
{
   $mail->AddCC($email, $name);
}

How to find third or n?? maximum salary from salary table?

In SQL Server 2012+, OFFSET...FETCH would be an efficient way to achieve this:

DECLARE @N AS INT;
SET @N = 3;

SELECT
    EmpSalary
FROM
    dbo.Salary
ORDER BY
    EmpSalary DESC
OFFSET (@N-1) ROWS
FETCH NEXT 1 ROWS ONLY

How to diff one file to an arbitrary version in Git?

You can do:

git diff master~20:pom.xml pom.xml

... to compare your current pom.xml to the one from master 20 revisions ago through the first parent. You can replace master~20, of course, with the object name (SHA1sum) of a commit or any of the many other ways of specifying a revision.

Note that this is actually comparing the old pom.xml to the version in your working tree, not the version committed in master. If you want that, then you can do the following instead:

git diff master~20:pom.xml master:pom.xml

Showing line numbers in IPython/Jupyter Notebooks

Select the Toggle Line Number Option from the View -> Toggle Line Number.

The menu looks like this

How to return a html page from a restful controller in spring boot?

I did three things:

  • Put the HTML page in {project.basedir}/resources/static/myPage.html;
  • Switch @RestController to @Controller;
  • This is my controller:
@RequestMapping(method = RequestMethod.GET, value = "/")
public String aName() {
    return "myPage.html";
}

No particular dependency is needed.

How do I show the schema of a table in a MySQL database?

SHOW CREATE TABLE yourTable;

or

SHOW COLUMNS FROM yourTable;

Multiple line comment in Python

Try this

'''
This is a multiline
comment. I can type here whatever I want.
'''

Python does have a multiline string/comment syntax in the sense that unless used as docstrings, multiline strings generate no bytecode -- just like #-prepended comments. In effect, it acts exactly like a comment.

On the other hand, if you say this behavior must be documented in the official docs to be a true comment syntax, then yes, you would be right to say it is not guaranteed as part of the language specification.

In any case your editor should also be able to easily comment-out a selected region (by placing a # in front of each line individually). If not, switch to an editor that does.

Programming in Python without certain text editing features can be a painful experience. Finding the right editor (and knowing how to use it) can make a big difference in how the Python programming experience is perceived.

Not only should the editor be able to comment-out selected regions, it should also be able to shift blocks of code to the left and right easily, and should automatically place the cursor at the current indentation level when you press Enter. Code folding can also be useful.

XSD - how to allow elements in any order any number of times?

The alternative formulation of the question added in a later edit seems still to be unanswered: how to specify that among the children of an element, there must be one named child3, one named child4, and any number named child1 or child2, with no constraint on the order in which the children appear.

This is a straightforwardly definable regular language, and the content model you need is isomorphic to a regular expression defining the set of strings in which the digits '3' and '4' each occur exactly once, and the digits '1' and '2' occur any number of times. If it's not obvious how to write this, it may help to think about what kind of finite state machine you would build to recognize such a language. It would have at least four distinct states:

  • an initial state in which neither '3' nor '4' has been seen
  • an intermediate state in which '3' has been seen but not '4'
  • an intermediate state in which '4' has been seen but not '3'
  • a final state in which both '3' and '4' have been seen

No matter what state the automaton is in, '1' and '2' may be read; they do not change the machine's state. In the initial state, '3' or '4' will also be accepted; in the intermediate states, only '4' or '3' is accepted; in the final state, neither '3' nor '4' is accepted. The structure of the regular expression is easiest to understand if we first define a regex for the subset of our language in which only '3' and '4' occur:

(34)|(43)

To allow '1' or '2' to occur any number of times at a given location, we can insert (1|2)* (or [12]* if our regex language accepts that notation). Inserting this expression at all available locations, we get

(1|2)*((3(1|2)*4)|(4(1|2)*3))(1|2)*

Translating this into a content model is straightforward. The basic structure is equivalent to the regex (34)|(43):

<xsd:complexType name="paul0">
  <xsd:choice>
    <xsd:sequence>
      <xsd:element ref="child3"/>
      <xsd:element ref="child4"/>
    </xsd:sequence>
    <xsd:sequence>
      <xsd:element ref="child4"/>
      <xsd:element ref="child3"/>
    </xsd:sequence>
  </xsd:choice>
</xsd:complexType>

Inserting a zero-or-more choice of child1 and child2 is straightforward:

<xsd:complexType name="paul1">
  <xsd:sequence>
    <xsd:choice minOccurs="0" maxOccurs="unbounded">
      <xsd:element ref="child1"/>
      <xsd:element ref="child2"/>
    </xsd:choice>      
    <xsd:choice>
      <xsd:sequence>
        <xsd:element ref="child3"/>
        <xsd:choice minOccurs="0" maxOccurs="unbounded">
          <xsd:element ref="child1"/>
          <xsd:element ref="child2"/>
        </xsd:choice>      
        <xsd:element ref="child4"/>
      </xsd:sequence>
      <xsd:sequence>
        <xsd:element ref="child4"/>
        <xsd:choice minOccurs="0" maxOccurs="unbounded">
          <xsd:element ref="child1"/>
          <xsd:element ref="child2"/>
        </xsd:choice>      
        <xsd:element ref="child3"/>
      </xsd:sequence>
    </xsd:choice>
    <xsd:choice minOccurs="0" maxOccurs="unbounded">
      <xsd:element ref="child1"/>
      <xsd:element ref="child2"/>
    </xsd:choice>      
  </xsd:sequence>
</xsd:complexType>

If we want to minimize the bulk a bit, we can define a named group for the repeating choices of child1 and child2:

<xsd:group name="onetwo">
  <xsd:choice>
    <xsd:element ref="child1"/>
    <xsd:element ref="child2"/>
  </xsd:choice>   
</xsd:group>

<xsd:complexType name="paul2">
  <xsd:sequence>
    <xsd:group ref="onetwo" minOccurs="0" maxOccurs="unbounded"/>
    <xsd:choice>
      <xsd:sequence>
        <xsd:element ref="child3"/>
        <xsd:group ref="onetwo" minOccurs="0" maxOccurs="unbounded"/>
        <xsd:element ref="child4"/>
      </xsd:sequence>
      <xsd:sequence>
        <xsd:element ref="child4"/>
        <xsd:group ref="onetwo" minOccurs="0" maxOccurs="unbounded"/>
        <xsd:element ref="child3"/>
      </xsd:sequence>
    </xsd:choice>  
    <xsd:group ref="onetwo" minOccurs="0" maxOccurs="unbounded"/>
  </xsd:sequence>
</xsd:complexType>

In XSD 1.1, some of the constraints on all-groups have been lifted, so it's possible to define this content model more concisely:

<xsd:complexType name="paul3">
  <xsd:all>
    <xsd:element ref="child1" minOccurs="0" maxOccurs="unbounded"/>
    <xsd:element ref="child2" minOccurs="0" maxOccurs="unbounded"/>
    <xsd:element ref="child3"/>
    <xsd:element ref="child4"/>      
  </xsd:all>
</xsd:complexType>

But as can be seen from the examples given earlier, these changes to all-groups do not in fact change the expressive power of the language; they only make the definition of certain kinds of languages more succinct.

How to write an inline IF statement in JavaScript?

You can also approximate an if/else using only Logical Operators.

(a && b) || c

The above is roughly the same as saying:

a ? b : c

And of course, roughly the same as:

if ( a ) { b } else { c }

I say roughly because there is one difference with this approach, in that you have to know that the value of b will evaluate as true, otherwise you will always get c. Bascially you have to realise that the part that would appear if () { here } is now part of the condition that you place if ( here ) { }.

The above is possible due to JavaScripts behaviour of passing / returning one of the original values that formed the logical expression, which one depends on the type of operator. Certain other languages, like PHP, carry on the actual result of the operation i.e. true or false, meaning the result is always true or false; e.g:

14 && 0          /// results as 0,  not false
14 || 0          /// results as 14, not true
1 && 2 && 3 && 4 /// results as 4,  not true
true && ''       /// results as ''
{} || '0'        /// results as {}

One main benefit, compared with a normal if statement, is that the first two methods can operate on the righthand-side of an argument i.e. as part of an assignment.

d = (a && b) || c;
d = a ? b : c;

if `a == true` then `d = b` else `d = c`

The only way to achieve this with a standard if statement would be to duplicate the assigment:

if ( a ) { d = b } else { d = c }

You may ask why use just Logical Operators instead of the Ternary Operator, for simple cases you probably wouldn't, unless you wanted to make sure a and b were both true. You can also achieve more streamlined complex conditions with the Logical operators, which can get quite messy using nested ternary operations... then again if you want your code to be easily readable, neither are really that intuative.

On localhost, how do I pick a free port number?

If you only need to find a free port for later use, here is a snippet similar to a previous answer, but shorter, using socketserver:

import socketserver

with socketserver.TCPServer(("localhost", 0), None) as s:
    free_port = s.server_address[1]

Note that the port is not guaranteed to remain free, so you may need to put this snippet and the code using it in a loop.

Google Maps V3 - How to calculate the zoom level for a given bounds

map.getBounds() is not momentary operation, so I use in similar case event handler. Here is my example in Coffeescript

@map.fitBounds(@bounds)
google.maps.event.addListenerOnce @map, 'bounds_changed', =>
  @map.setZoom(12) if @map.getZoom() > 12

Excel data validation with suggestions/autocomplete

ExtendOffice.com offers a VBA solution that worked for me in Excel 2016. Here's my description of the steps. I included additional details to make it easier. I also modified the VBA code slightly. If this doesn't work for you, retry the steps or check out the instructions on the ExtendOffice page.

  1. Add data validation to a cell (or range of cells). Allow = List. Source = [the range with the values you want for the auto-complete / drop-down]. Click OK. You should now have a drop-down but with a weak auto-complete feature.

    enter image description here

  2. With a cell containing your newly added data validation, insert an ActiveX combo box (NOT a form control combo box). This is done from the Developer ribbon. If you don't have the Developer ribbon you will need to add it from the Excel options menu.

    enter image description here

  3. From the Developer tab in the Controls section, click "Design Mode". Select the combo box you just inserted. Then in the same ribbon section click "Properties". In the Properties window, change the name of the combo box to "TempComboBox".

    enter image description here

  4. Press ALT + F11 to go to the Visual Basic Editor. On the left-hand side, double click the worksheet with your data validation to open the code for that sheet. Copy and paste the following code onto the sheet. NOTE: I modified the code slightly so that it works even with Option Explicit enabled at the top of the sheet.

    Option Explicit
    
    Private Sub Worksheet_SelectionChange(ByVal target As Range)
    'Update by Extendoffice: 2018/9/21
    ' Update by Chris Brackett 2018-11-30
    
    Dim xWs As Worksheet
    Set xWs = Application.ActiveSheet
    
    On Error Resume Next
    
    Dim xCombox As OLEObject
    Set xCombox = xWs.OLEObjects("TempCombo")
    
    ' Added this to auto select all text when activating the combox box.
    xCombox.SetFocus
    
    With xCombox
        .ListFillRange = vbNullString
        .LinkedCell = vbNullString
        .Visible = False
    End With
    
    
    Dim xStr As String
    Dim xArr
    
    
    If target.Validation.Type = xlValidateList Then
        ' The target cell contains Data Validation.
    
        target.Validation.InCellDropdown = False
    
    
        ' Cancel the "SelectionChange" event.
        Dim Cancel As Boolean
        Cancel = True
    
    
        xStr = target.Validation.Formula1
        xStr = Right(xStr, Len(xStr) - 1)
    
        If xStr = vbNullString Then Exit Sub
    
        With xCombox
            .Visible = True
            .Left = target.Left
            .Top = target.Top
            .Width = target.Width + 5
            .Height = target.Height + 5
            .ListFillRange = xStr
    
            If .ListFillRange = vbNullString Then
                xArr = Split(xStr, ",")
                Me.TempCombo.List = xArr
            End If
    
            .LinkedCell = target.Address
    
        End With
    
        xCombox.Activate
        Me.TempCombo.DropDown
    
    End If
    End Sub
    
    Private Sub TempCombo_KeyDown( _
                    ByVal KeyCode As MSForms.ReturnInteger, _
                    ByVal Shift As Integer)
        Select Case KeyCode
            Case 9  ' Tab key
                Application.ActiveCell.Offset(0, 1).Activate
            Case 13 ' Pause key
                Application.ActiveCell.Offset(1, 0).Activate
        End Select
    End Sub
    
  5. Make sure the the "Microsoft Forms 2.0 Object Library" is referenced. In the Visual Basic Editor, go to Tools > References, check the box next to that library (if not already checked) and click OK. To verify that it worked, go to Debug > Compile VBA Project.

  6. Finally, save your project and click in a cell with the data validation you added. You should see a combo box with a drop-down list of suggestions that updates with each letter you type.

enter image description here

enter image description here

preventDefault() on an <a> tag

After several operations, when the page should finally go to <a href"..."> link you can do the following:

jQuery("a").click(function(e){
    var self = jQuery(this);
    var href = self.attr('href');
    e.preventDefault();
    // needed operations

    window.location = href;
});

pow (x,y) in Java

^ is the bitwise exclusive OR (XOR) operator in Java (and many other languages). It is not used for exponentiation. For that, you must use Math.pow.

What does MissingManifestResourceException mean and how to fix it?

When I run in a similar issue, in Vs 2012, it turned out that the "Custom Tool Namespace" property of the resx file was wrong (in my case, actually, it was unset, so the generated code yeld this exception at runtime). My final set of properties for the resx file was something like this:

  • Build action: Embedded Resource
  • Copy to Output Directory: Do not copy
  • Custom Tool: ResXFileCodeGenerator
  • Custom Tool Namespace: My.Project.S.Proper.Namespace

How many socket connections can a web server handle?

In short: You should be able to achieve in the order of millions of simultaneous active TCP connections and by extension HTTP request(s). This tells you the maximum performance you can expect with the right platform with the right configuration.

Today, I was worried whether IIS with ASP.NET would support in the order of 100 concurrent connections (look at my update, expect ~10k responses per second on older ASP.Net Mono versions). When I saw this question/answers, I couldn't resist answering myself, many answers to the question here are completely incorrect.

Best Case

The answer to this question must only concern itself with the simplest server configuration to decouple from the countless variables and configurations possible downstream.

So consider the following scenario for my answer:

  1. No traffic on the TCP sessions, except for keep-alive packets (otherwise you would obviously need a corresponding amount of network bandwidth and other computer resources)
  2. Software designed to use asynchronous sockets and programming, rather than a hardware thread per request from a pool. (ie. IIS, Node.js, Nginx... webserver [but not Apache] with async designed application software)
  3. Good performance/dollar CPU / Ram. Today, arbitrarily, let's say i7 (4 core) with 8GB of RAM.
  4. A good firewall/router to match.
  5. No virtual limit/governor - ie. Linux somaxconn, IIS web.config...
  6. No dependency on other slower hardware - no reading from harddisk, because it would be the lowest common denominator and bottleneck, not network IO.

Detailed Answer

Synchronous thread-bound designs tend to be the worst performing relative to Asynchronous IO implementations.

WhatsApp can handle a million WITH traffic on a single Unix flavoured OS machine - https://blog.whatsapp.com/index.php/2012/01/1-million-is-so-2011/.

And finally, this one, http://highscalability.com/blog/2013/5/13/the-secret-to-10-million-concurrent-connections-the-kernel-i.html, goes into a lot of detail, exploring how even 10 million could be achieved. Servers often have hardware TCP offload engines, ASICs designed for this specific role more efficiently than a general purpose CPU.

Good software design choices

Asynchronous IO design will differ across Operating Systems and Programming platforms. Node.js was designed with asynchronous in mind. You should use Promises at least, and when ECMAScript 7 comes along, async/await. C#/.Net already has full asynchronous support like node.js. Whatever the OS and platform, asynchronous should be expected to perform very well. And whatever language you choose, look for the keyword "asynchronous", most modern languages will have some support, even if it's an add-on of some sort.

To WebFarm?

Whatever the limit is for your particular situation, yes a web-farm is one good solution to scaling. There are many architectures for achieving this. One is using a load balancer (hosting providers can offer these, but even these have a limit, along with bandwidth ceiling), but I don't favour this option. For Single Page Applications with long-running connections, I prefer to instead have an open list of servers which the client application will choose from randomly at startup and reuse over the lifetime of the application. This removes the single point of failure (load balancer) and enables scaling through multiple data centres and therefore much more bandwidth.

Busting a myth - 64K ports

To address the question component regarding "64,000", this is a misconception. A server can connect to many more than 65535 clients. See https://networkengineering.stackexchange.com/questions/48283/is-a-tcp-server-limited-to-65535-clients/48284

By the way, Http.sys on Windows permits multiple applications to share the same server port under the HTTP URL schema. They each register a separate domain binding, but there is ultimately a single server application proxying the requests to the correct applications.

Update 2019-05-30

Here is an up to date comparison of the fastest HTTP libraries - https://www.techempower.com/benchmarks/#section=data-r16&hw=ph&test=plaintext

  • Test date: 2018-06-06
  • Hardware used: Dell R440 Xeon Gold + 10 GbE
  • The leader has ~7M plaintext reponses per second (responses not connections)
  • The second one Fasthttp for golang advertises 1.5M concurrent connections - see https://github.com/valyala/fasthttp
  • The leading languages are Rust, Go, C++, Java, C, and even C# ranks at 11 (6.9M per second). Scala and Clojure rank further down. Python ranks at 29th at 2.7M per second.
  • At the bottom of the list, I note laravel and cakephp, rails, aspnet-mono-ngx, symfony, zend. All below 10k per second. Note, most of these frameworks are build for dynamic pages and quite old, there may be newer variants that feature higher up in the list.
  • Remember this is HTTP plaintext, not for the Websocket specialty: many people coming here will likely be interested in concurrent connections for websocket.

Visual Studio C# IntelliSense not automatically displaying

Steps to fix are:

      Tools
      Import and Export Settings
      Reset all settings
      Back up your config
      Select your environment settings and finish

How to use XPath contains() here?

This is a new answer to an old question about a common misconception about contains() in XPath...

Summary: contains() means contains a substring, not contains a node.

Detailed Explanation

This XPath is often misinterpreted:

//ul[contains(li, 'Model')]

Wrong interpretation: Select those ul elements that contain an li element with Model in it.

This is wrong because

  1. contains(x,y) expects x to be a string, and
  2. the XPath rule for converting multiple elements to a string is this:

    A node-set is converted to a string by returning the string-value of the node in the node-set that is first in document order. If the node-set is empty, an empty string is returned.

Right interpretation: Select those ul elements whose first li child has a string-value that contains a Model substring.

Examples

XML

<r>
  <ul id="one">
    <li>Model A</li>
    <li>Foo</li>
  </ul>
  <ul id="two">
    <li>Foo</li>
    <li>Model A</li>
  </ul>
</r> 

XPaths

  • //ul[contains(li, 'Model')] selects the one ul element.

    Note: The two ul element is not selected because the string-value of the first li child of the two ul is Foo, which does not contain the Model substring.

  • //ul[li[contains(.,'Model')]] selects the one and two ul elements.

    Note: Both ul elements are selected because contains() is applied to each li individually. (Thus, the tricky multiple-element-to-string conversion rule is avoided.) Both ul elements do have an li child whose string value contains the Model substring -- position of the li element no longer matters.

See also

unary operator expected in shell script when comparing null value with string

Since the value of $var is the empty string, this:

if [ $var == $var1 ]; then

expands to this:

if [ == abcd ]; then

which is a syntax error.

You need to quote the arguments:

if [ "$var" == "$var1" ]; then

You can also use = rather than ==; that's the original syntax, and it's a bit more portable.

If you're using bash, you can use the [[ syntax, which doesn't require the quotes:

if [[ $var = $var1 ]]; then

Even then, it doesn't hurt to quote the variable reference, and adding quotes:

if [[ "$var" = "$var1" ]]; then

might save a future reader a moment trying to remember whether [[ ... ]] requires them.

Convert dictionary to list collection in C#

If you want convert Keys:

List<string> listNumber = dicNumber.Keys.ToList();

else if you want convert Values:

List<string> listNumber = dicNumber.Values.ToList();

Python xticks in subplots

There are two ways:

  1. Use the axes methods of the subplot object (e.g. ax.set_xticks and ax.set_xticklabels) or
  2. Use plt.sca to set the current axes for the pyplot state machine (i.e. the plt interface).

As an example (this also illustrates using setp to change the properties of all of the subplots):

import matplotlib.pyplot as plt

fig, axes = plt.subplots(nrows=3, ncols=4)

# Set the ticks and ticklabels for all axes
plt.setp(axes, xticks=[0.1, 0.5, 0.9], xticklabels=['a', 'b', 'c'],
        yticks=[1, 2, 3])

# Use the pyplot interface to change just one subplot...
plt.sca(axes[1, 1])
plt.xticks(range(3), ['A', 'Big', 'Cat'], color='red')

fig.tight_layout()
plt.show()

enter image description here

Assignment inside lambda expression in Python

Normal assignment (=) is not possible inside a lambda expression, although it is possible to perform various tricks with setattr and friends.

Solving your problem, however, is actually quite simple:

input = [Object(name=""), Object(name="fake_name"), Object(name="")]
output = filter(
    lambda o, _seen=set():
        not (not o and o in _seen or _seen.add(o)),
    input
    )

which will give you

[Object(Object(name=''), name='fake_name')]

As you can see, it's keeping the first blank instance instead of the last. If you need the last instead, reverse the list going in to filter, and reverse the list coming out of filter:

output = filter(
    lambda o, _seen=set():
        not (not o and o in _seen or _seen.add(o)),
    input[::-1]
    )[::-1]

which will give you

[Object(name='fake_name'), Object(name='')]

One thing to be aware of: in order for this to work with arbitrary objects, those objects must properly implement __eq__ and __hash__ as explained here.

What is the => assignment in C# in a property signature

You can even write this:

    private string foo = "foo";

    private string bar
    {
        get => $"{foo}bar";
        set
        {
            foo = value;
        }
    }