Programs & Examples On #Diskarbitration

DiskArbitration.framework is available on OS X, and provides mechanisms for registering for mount/unmount notification and blocking mount/unmount events.

Check whether an input string contains a number in javascript

You can do this using javascript. No need for Jquery or Regex

function isNumeric(n) {
  return !isNaN(parseFloat(n)) && isFinite(n);
}

While implementing

var val = $('yourinputelement').val();
if(isNumeric(val)) { alert('number'); } 
else { alert('not number'); }

Update: To check if a string has numbers in them, you can use regular expressions to do that

var matches = val.match(/\d+/g);
if (matches != null) {
    alert('number');
}

Selecting multiple classes with jQuery

// Due to this Code ): Syntax problem.    
$('.myClass', '.myOtherClass').removeClass('theclass'); 

According to jQuery documentation: https://api.jquery.com/multiple-selector/

When can select multiple classes in this way:

jQuery(“selector1, selector2, selectorN”) // double Commas. // IS valid.
jQuery('selector1, selector2, selectorN') // single Commas. // Is valid.

by enclosing all the selectors in a single '...' ' or double commas, "..."

So in your case the correct way to call multiple classes is:

$('.myClass', '.myOtherClass').removeClass('theclass'); // your Code // Invalid.
$('.myClass , .myOtherClass').removeClass('theclass');  // Correct Code // Is valid.

How to install a .ipa file into my iPhone?

You need to install the provisioning profile (drag and drop it into iTunes). Then drag and drop the .ipa. Ensure you device is set to sync apps, and try again.

json_encode/json_decode - returns stdClass instead of Array in PHP

    var_dump(json_decode('{"0":0}'));    // output: object(0=>0)
    var_dump(json_decode('[0]'));          //output: [0]

    var_dump(json_decode('{"0":0}', true));//output: [0]
    var_dump(json_decode('[0]', true));    //output: [0]

If you decode the json into array, information will be lost in this situation.

SQL JOIN vs IN performance?

Funny you mention that, I did a blog post on this very subject.

See Oracle vs MySQL vs SQL Server: Aggregation vs Joins

Short answer: you have to test it and individual databases vary a lot.

HTTP Content-Type Header and JSON

Recently ran into a problem with this and a Chrome extension that was corrupting a JSON stream when the response header labeled the content-type as 'text/html' apparently extensions can and will use the response header to alter the content prior to further processing by the browser. Changing the content-type fixed the issue.

How do I run all Python unit tests in a directory?

This is an old question, but what worked for me now (in 2019) is:

python -m unittest *_test.py

All my test files are in the same folder as the source files and they end with _test.

How to remove margin space around body or clear default css styles

body has default margins: http://www.w3.org/TR/CSS2/sample.html

body { margin:0; } /* Remove body margins */

Or you could use this useful Global reset

* { margin:0; padding:0; box-sizing:border-box; }

If you want something less * global than:

html, body, body div, span, object, iframe, h1, h2, h3, h4, h5, h6, p, blockquote, pre, abbr, address, cite, code, del, dfn, em, img, ins, kbd, q, samp, small, strong, sub, sup, var, b, i, dl, dt, dd, ol, ul, li, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td, article, aside, figure, footer, header, hgroup, menu, nav, section, time, mark, audio, video {
    margin: 0;
    padding: 0;
    border: 0;
    outline: 0;
    font-size: 100%;
    vertical-align: baseline;
    background: transparent;
}

some other CSS Reset:

http://yui.yahooapis.com/3.5.0/build/cssreset/cssreset-min.css
http://meyerweb.com/eric/tools/css/reset/
https://github.com/necolas/normalize.css/
http://html5doctor.com/html-5-reset-stylesheet/

Use getElementById on HTMLElement instead of HTMLDocument

Sub Scrape()
    Dim Browser As InternetExplorer
    Dim Document As htmlDocument
    Dim Elements As IHTMLElementCollection
    Dim Element As IHTMLElement

    Set Browser = New InternetExplorer
    Browser.Visible = True
    Browser.navigate "http://www.stackoverflow.com"

    Do While Browser.Busy And Not Browser.readyState = READYSTATE_COMPLETE
        DoEvents
    Loop

    Set Document = Browser.Document

    Set Elements = Document.getElementById("hmenus").getElementsByTagName("li")
    For Each Element In Elements
        Debug.Print Element.innerText
        'Questions
        'Tags
        'Users
        'Badges
        'Unanswered
        'Ask Question
    Next Element

    Set Document = Nothing
    Set Browser = Nothing
End Sub

What does getActivity() mean?

getActivity() is used for fragment. For activity, wherever you can use this, you can replace the this in fragment in similar cases with getActivity().

How to write log to file

The default logger in Go writes to stderr (2). redirect to file

import ( 
    "syscall"
    "os" 
 )
func main(){
  fErr, err = os.OpenFile("Errfile", os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
  syscall.Dup2(int(fErr.Fd()), 1) /* -- stdout */
  syscall.Dup2(int(fErr.Fd()), 2) /* -- stderr */

}

How to break a while loop from an if condition inside the while loop?

while(something.hasnext())
do something...
   if(contains something to process){
      do something...
      break;
   }
}

Just use the break statement;

For eg:this just prints "Breaking..."

while (true) {
     if (true) {
         System.out.println("Breaking...");
         break;
     }
     System.out.println("Did this print?");
}

Creating table variable in SQL server 2008 R2

@tableName Table variables are alive for duration of the script running only i.e. they are only session level objects.

To test this, open two query editor windows under sql server management studio, and create table variables with same name but different structures. You will get an idea. The @tableName object is thus temporary and used for our internal processing of data, and it doesn't contribute to the actual database structure.

There is another type of table object which can be created for temporary use. They are #tableName objects declared like similar create statement for physical tables:

Create table #test (Id int, Name varchar(50))

This table object is created and stored in temp database. Unlike the first one, this object is more useful, can store large data and takes part in transactions etc. These tables are alive till the connection is open. You have to drop the created object by following script before re-creating it.

IF OBJECT_ID('tempdb..#test') IS NOT NULL
  DROP TABLE #test 

Hope this makes sense !

MySQL timestamp select date range

Whenever possible, avoid applying functions to a column in the where clause:

SELECT *
  FROM table_name
 WHERE timestamp >= UNIX_TIMESTAMP('2010-10-01 00:00:00') 
   AND timestamp <  UNIX_TIMESTAMP('2010-11-01 00:00:00');

Applying a function to the timestamp column (e.g., FROM_UNIXTIME(timestamp) = ...) makes indexing much harder.

How to select distinct rows in a datatable and store into an array

The most simple solution is to use LINQ and then transform the result to a DataTable

    //data is a DataTable that you want to change
    DataTable result = data.AsEnumerable().Distinct().CopyToDataTable < DataRow > ();

This is valid only for asp.net 4.0 ^ Framework and it needs the reference to System.Data.DataSetExtensions as Ivan Ferrer Villa pointed out

How to find a whole word in a String in java

You can also use regex matching with the \b flag (whole word boundary).

Align DIV's to bottom or baseline

You need to add this:

#parentDiv {
  position: relative;
}

#parentDiv .childDiv {
  position: absolute;
  bottom: 0;
  left: 0;
}

When declaring absolute element, it is positioned according to its nearest parent that is not static (it must be absolute, relative or fixed).

How to allow CORS in react.js?

You just have to add cors to your backend server.js file in order to do cross-origin API Calls.

const cors = require('cors');
app.use(cors())

Transaction marked as rollback only: How do I find the cause

I struggled with this exception while running my application.

Finally the problem was on the sql query. i mean that the query is wrong.

please verify your query. This is my suggestion

Bootstrap 3 collapse accordion: collapse all works but then cannot expand all while maintaining data-parent

For whatever reason $('.panel-collapse').collapse({'toggle': true, 'parent': '#accordion'}); only seems to work the first time and it only works to expand the collapsible. (I tried to start with a expanded collapsible and it wouldn't collapse.)

It could just be something that runs once the first time you initialize collapse with those parameters.

You will have more luck using the show and hide methods.

Here is an example:

$(function() {

  var $active = true;

  $('.panel-title > a').click(function(e) {
    e.preventDefault();
  });

  $('.collapse-init').on('click', function() {
    if(!$active) {
      $active = true;
      $('.panel-title > a').attr('data-toggle', 'collapse');
      $('.panel-collapse').collapse('hide');
      $(this).html('Click to disable accordion behavior');
    } else {
      $active = false;
      $('.panel-collapse').collapse('show');
      $('.panel-title > a').attr('data-toggle','');
      $(this).html('Click to enable accordion behavior');
    }
  });

});

http://bootply.com/98201

Update

Granted KyleMit seems to have a way better handle on this then me. I'm impressed with his answer and understanding.

I don't understand what's going on or why the show seemed to be toggling in some places.

But After messing around for a while.. Finally came with the following solution:

$(function() {
  var transition = false;
  var $active = true;

  $('.panel-title > a').click(function(e) {
    e.preventDefault();
  });

  $('#accordion').on('show.bs.collapse',function(){
    if($active){
        $('#accordion .in').collapse('hide');
    }
  });

  $('#accordion').on('hidden.bs.collapse',function(){
    if(transition){
        transition = false;
        $('.panel-collapse').collapse('show');
    }
  });

  $('.collapse-init').on('click', function() {
    $('.collapse-init').prop('disabled','true');
    if(!$active) {
      $active = true;
      $('.panel-title > a').attr('data-toggle', 'collapse');
      $('.panel-collapse').collapse('hide');
      $(this).html('Click to disable accordion behavior');
    } else {
      $active = false;
      if($('.panel-collapse.in').length){
        transition = true;
        $('.panel-collapse.in').collapse('hide');       
      }
      else{
        $('.panel-collapse').collapse('show');
      }
      $('.panel-title > a').attr('data-toggle','');
      $(this).html('Click to enable accordion behavior');
    }
    setTimeout(function(){
        $('.collapse-init').prop('disabled','');
    },800);
  });
});

http://bootply.com/98239

Python; urllib error: AttributeError: 'bytes' object has no attribute 'read'

I'm not familiar with python 3 yet, but it seems like urllib.request.urlopen().read() returns a byte object rather than string.

You might try to feed it into a StringIO object, or even do a str(response).

Camera access through browser

I think this one is working. Recording a video or audio;

<input type="file" accept="video/*;capture=camcorder">
<input type="file" accept="audio/*;capture=microphone">

or (new method)

<device type="media" onchange="update(this.data)"></device>
<video autoplay></video>
<script>
  function update(stream) {
    document.querySelector('video').src = stream.url;
  }
</script>

If it is not, probably will work on ios6, more detail can be found at get user media

Best way to concatenate List of String objects?

if you have json in your dependencies.you can use new JSONArray(list).toString()

How to remove the default link color of the html hyperlink 'a' tag?

a:link{color:inherit;}

this is the simple one line can do all stuffs for you <3

Troubleshooting BadImageFormatException

When I faced this issue the following solved it for me:

I was calling a OpenCV dll from inside another exe, my dll did not contained the already needed opencv dlls like highgui, features2d, and etc available in the folder of my exe file. I copied all these to the directory of my exe project and it suddenly worked.

how to convert `content://media/external/images/media/Y` to `file:///storage/sdcard0/Pictures/X.jpg` in android?

If you just want the bitmap, This too works

InputStream inputStream = mContext.getContentResolver().openInputStream(uri);
Bitmap bmp = BitmapFactory.decodeStream(inputStream);
if( inputStream != null ) inputStream.close();

sample uri : content://media/external/images/media/12345

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

You can also use SUM + IF which is shorter than SUM + CASE:

SELECT
    count(id)
    , SUM(IF(kind=1, 1, 0)) AS countKindOne
    , SUM(CASE WHEN kind=2 THEN 1 ELSE 0 END) AS countKindTwo

How to force Hibernate to return dates as java.util.Date instead of Timestamp?

Just add the this annotation @Temporal(TemporalType.DATE) for a java.util.Date field in your entity class.

More information available in this stackoverflow answer.

how do I create an array in jquery?

Here is the clear working example:

//creating new array
var custom_arr1 = [];


//storing value in array
custom_arr1.push("test");
custom_arr1.push("test1");

alert(custom_arr1);
//output will be  test,test1

Should I use Java's String.format() if performance is important?

Generally you should use String.Format because it's relatively fast and it supports globalization (assuming you're actually trying to write something that is read by the user). It also makes it easier to globalize if you're trying to translate one string versus 3 or more per statement (especially for languages that have drastically different grammatical structures).

Now if you never plan on translating anything, then either rely on Java's built in conversion of + operators into StringBuilder. Or use Java's StringBuilder explicitly.

What’s the difference between "Array()" and "[]" while declaring a JavaScript array?

Using the Array constructor makes a new array of the desired length and populates each of the indices with undefined, the assigned an array to a variable one creates the indices that you give it info for.

Jquery selector input[type=text]')

Using a normal css selector:

$('.sys input[type=text], .sys select').each(function() {...})

If you don't like the repetition:

$('.sys').find('input[type=text],select').each(function() {...})

Or more concisely, pass in the context argument:

$('input[type=text],select', '.sys').each(function() {...})

Note: Internally jQuery will convert the above to find() equivalent

http://api.jquery.com/jQuery/

Internally, selector context is implemented with the .find() method, so $('span', this) is equivalent to $(this).find('span').

I personally find the first alternative to be the most readable :), your take though

jQuery event for images loaded

As per this answer, you can use the jQuery load event on the window object instead of the document:

jQuery(window).load(function() {
    console.log("page finished loading now.");
});

This will be triggered after all content on the page has been loaded. This differs from jQuery(document).load(...) which is triggered after the DOM has finished loading.

Creating a border like this using :before And :after Pseudo-Elements In CSS?

See the following snippet, is this what you want?

_x000D_
_x000D_
body {
    background: silver;
    padding: 0 10px;
}

#content:after {
    height: 10px;
    display: block;
    width: 100px;
    background: #808080;
    border-right: 1px white;
    content: '';
}

#footer:before {
    display: block;
    content: '';
    background: silver;
    height: 10px;
    margin-top: -20px;
    margin-left: 101px;
}

#content {
    background: white;
}


#footer {
    padding-top: 10px;
    background: #404040;
}

p {
    padding: 100px;
    text-align: center;
}

#footer p {
    color: white;
}
_x000D_
<body>
    <div id="content"><p>#content</p></div>
    <div id="footer"><p>#footer</p></div>
</body>
_x000D_
_x000D_
_x000D_

JSFiddle

How to filter array when object key value is in array

Old way of doing it. Many might hate this way of doing but i still many time find this is still better in my perspective.

Input:

var records = [{
    "empid":1,
    "fname": "X",
    "lname": "Y"
},
{
    "empid":2,
    "fname": "A",
    "lname": "Y"
},
{
    "empid":3,
    "fname": "B",
    "lname": "Y"
},
{
    "empid":4,
    "fname": "C",
    "lname": "Y"
},
{
    "empid":5,
    "fname": "C",
    "lname": "Y"
}
]

var newArr = [1,4,5];

Code:

var newObj = [];
for(var a = 0 ; a < records.length ; a++){
 if(newArr.indexOf(records[a].empid) > -1){
  newObj.push(records[a]);
 }
}

The indexOf() method returns the first index at which a given element can be found in the array, or -1 if it is not present.

Reference - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/indexOf

Output:

[{
    "empid": 1,
    "fname": "X",
    "lname": "Y"
}, {
    "empid": 4,
    "fname": "C",
    "lname": "Y"
}, {
    "empid": 5,
    "fname": "C",
    "lname": "Y"
}]

How to check if a user is logged in (how to properly use user.is_authenticated)?

For Django 2.0+ versions use:

    if request.auth:
       # Only for authenticated users.

For more info visit https://www.django-rest-framework.org/api-guide/requests/#auth

request.user.is_authenticated() has been removed in Django 2.0+ versions.

What is the syntax for Typescript arrow functions with generics?

In case you'd like to do it with async:

const request = async <T>(param1: string, param2: number) => {
  const res = await func();
  return res.response() as T;
}

And a more complex pattern, in case you'd like to wrap your function inside a generic counterpart, such as memoization (Example uses fast-memoize):

const request = memoize(
  async <T>(
    url: string,
    token?: string
  ) => {
    // Perform your code here
  }
);

See how you define the generic after the memoizing function.

Check if a string is a date value

function isDate(dateStr) {
  return !isNaN(new Date(dateStr).getDate());
}
  • This will work on any browser since it does not rely on "Invalid Date" check.
  • This will work with legacy code before ES6.
  • This will work without any library.
  • This will work regardless of any date format.
  • This does not rely on Date.parse which fails the purpose when values like "Spiderman 22" are in date string.
  • This does not ask us to write any RegEx.

IE prompts to open or save json result from server

Sadly, this is just another annoying quirk of using Internet Explorer.

enter image description here

The simple solution is to run a small .reg file on your PC, to tell IE to automatically open .json files, rather than nag about whether to open/save it.

I've put a copy of the file you'll need here:

JSON mime type

You'll need to have Admin rights to run this.

How to put text over images in html?

The <img> element is empty — it doesn't have an end tag.

If the image is a background image, use CSS. If it is a content image, then set position: relative on a container, then absolutely position the image and/or text within it.

Using ZXing to create an Android barcode scanning app

I had a problem with implementing the code until I found some website (I can't find it again right now) that explained that you need to include the package name in the name of the intent.putExtra.

It would pull up the application, but it wouldn't recognize any barcodes, and when I changed it from.

intent.putExtra("SCAN_MODE", "QR_CODE_MODE");

to

intent.putExtra("com.google.zxing.client.android.SCAN.SCAN_MODE", "QR_CODE_MODE");

It worked great. Just a tip for any other novice Android programmers.

How can I write to the console in PHP?

Use:

function console_log($data) {
    $bt = debug_backtrace();
    $caller = array_shift($bt);

    if (is_array($data))
        $dataPart = implode(',', $data);
    else
        $dataPart = $data;

    $toSplit = $caller['file'])) . ':' .
               $caller['line'] . ' => ' . $dataPart

    error_log(end(split('/', $toSplit));
}

How to change the playing speed of videos in HTML5?

According to this site, this is supported in the playbackRate and defaultPlaybackRate attributes, accessible via the DOM. Example:

/* play video twice as fast */
document.querySelector('video').defaultPlaybackRate = 2.0;
document.querySelector('video').play();

/* now play three times as fast just for the heck of it */
document.querySelector('video').playbackRate = 3.0;

The above works on Chrome 43+, Firefox 20+, IE 9+, Edge 12+.

Laravel Eloquent: How to get only certain columns from joined tables

This is how i do it

$posts = Post::with(['category' => function($query){
        $query->select('id', 'name');
      }])->get();

First answer by user2317976 did not work for me, i am using laravel 5.1

How to add soap header in java

Maven dependency

    <dependency>
        <groupId>org.springframework.ws</groupId>
        <artifactId>spring-ws-security</artifactId>
    </dependency>
    <dependency>
        <groupId>org.apache.ws.security</groupId>
        <artifactId>wss4j</artifactId>
        <version>1.6.19</version>
    </dependency>    

Configuration class

import org.springframework.ws.soap.security.wss4j.Wss4jSecurityInterceptor;

@Configuration
public class ConfigurationClass{

@Bean
public Wss4jSecurityInterceptor securityInterceptor() {
    Wss4jSecurityInterceptor wss4jSecurityInterceptor = new Wss4jSecurityInterceptor();
    wss4jSecurityInterceptor.setSecurementActions("UsernameToken");
    wss4jSecurityInterceptor.setSecurementMustUnderstand(true);
    wss4jSecurityInterceptor.setSecurementPasswordType("PasswordText");
    wss4jSecurityInterceptor.setSecurementUsername("123456789011");
    wss4jSecurityInterceptor.setSecurementPassword("TestPass123");
    return wss4jSecurityInterceptor;
}

Result xml

<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
<SOAP-ENV:Header>
    <wsse:Security
        xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"
        xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd" 
        SOAP-ENV:mustUnderstand="1">
        <wsse:UsernameToken wsu:Id="UsernameToken-F57F40DC89CD6998E214700450735811">
            <wsse:Username>123456789011</wsse:Username>
            <wsse:Password Type="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-username-token-profile-1.0#PasswordText">TestPass123</wsse:Password>
        </wsse:UsernameToken>
    </wsse:Security>
</SOAP-ENV:Header>
<SOAP-ENV:Body>
    ...
    something
    ...
</SOAP-ENV:Body>

How to present a simple alert message in java?

Assuming you already have a JFrame to call this from:

JOptionPane.showMessageDialog(frame, "thank you for using java");

See The Java Tutorials: How to Make Dialogs
See the JavaDoc

Why do I get "warning longer object length is not a multiple of shorter object length"?

I had a similar problem but it had to do with the structure and class of the object. I would check how dih_y2$MemberID is formatted.

Close Bootstrap Modal

In my case, I used a button to show the modal

<button type="button" class="btn btn-success" style="color:white"
    data-toggle="modal" data-target="#my-modal-to-show" >
    <i class="fas fa-plus"></i> Call MODAL
</button>

So in my code, to close the modal (that has the id = 'my-modal-to-show') I call that function (in Angular typescript):

closeById(modalId: string) {
  $(modalId).modal('toggle');
  $(modalId+ ' .close').click();
}

If I call $(modalId).modal('hide') it does't work and I don't know why

PS.: in my modal I coded that button element with .close class too

<button type="button" class="close" data-dismiss="modal" aria-label="Close"> 
    <span aria-hidden="true">&times;</span>
</button>

How to Bootstrap navbar static to fixed on scroll?

Use the affix component included with Bootstrap. Start with a 'navbar-static-top' and this will change it to fixed when the height of your header (content above the navbar) is reached...

$('#nav').affix({
      offset: {
        top: $('header').height()
      }
}); 

http://bootply.com/107973

Codeigniter unset session

$this->session->unset_userdata('session_value');

Visual Studio 2015 doesn't have cl.exe

In Visual Studio 2019 you can find cl.exe inside

32-BIT : C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.20.27508\bin\Hostx86\x86
64-BIT : C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.20.27508\bin\Hostx64\x64

Before trying to compile either run vcvars32 for 32-Bit compilation or vcvars64 for 64-Bit.

32-BIT : "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars32.bat"
64-BIT : "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat"

If you can't find the file or the directory, try going to C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC and see if you can find a folder with a version number. If you can't, then you probably haven't installed C++ through the Visual Studio Installation yet.

Turn on IncludeExceptionDetailInFaults (either from ServiceBehaviorAttribute or from the <serviceDebug> configuration behavior) on the server

I was also getting the same error, the WCF was working properly for me when i was using it in the Dev Environment with my credentials, but when someone else was using it in TEST, it was throwing the same error. I did a lot of research, and then instead of doing config updates, handled an exception in the WCF method with the help of fault exception. Also the identity for the WCF needs to be set with the same credentials which are having access in the database, someone might have changed your authority. Please find below the code for the same:

 [ServiceContract]
public interface IService1
{
    [OperationContract]
    [FaultContract(typeof(ServiceData))]
    ForDataset GetCCDBdata();

    [OperationContract]
    [FaultContract(typeof(ServiceData))]
    string GetCCDBdataasXMLstring();


    //[OperationContract]
    //string GetData(int value);

    //[OperationContract]
    //CompositeType GetDataUsingDataContract(CompositeType composite);

    // TODO: Add your service operations here
}

  [DataContract]
public class ServiceData
{
    [DataMember]
    public bool Result { get; set; }
    [DataMember]
    public string ErrorMessage { get; set; }
    [DataMember]
    public string ErrorDetails { get; set; }
}

in your service1.svc.cs you can use this in the catch block:

 catch (Exception ex)
        {
            myServiceData.Result = false;
            myServiceData.ErrorMessage = "unforeseen error occured. Please try later.";
            myServiceData.ErrorDetails = ex.ToString();
            throw new FaultException<ServiceData>(myServiceData, ex.ToString());
        }

And use this in the Client application like below code:

  ConsoleApplicationWCFClient.CCDB_HIG_service.ForDataset ds = obj.GetCCDBdata();

            string str = obj.GetCCDBdataasXMLstring();

        }

        catch (FaultException<ConsoleApplicationWCFClient.CCDB_HIG_service.ServiceData> Fex)
      {
          Console.WriteLine("ErrorMessage::" + Fex.Detail.ErrorMessage + Environment.NewLine);
          Console.WriteLine("ErrorDetails::" + Environment.NewLine + Fex.Detail.ErrorDetails);
          Console.ReadLine();
      }

Just try this, it will help for sure to get the exact issue.

changing the language of error message in required field in html5 contact form

This work for me.

<input oninvalid="this.setCustomValidity('custom text on invalid')" onchange="this.setCustomValidity('')" required>

onchange is a must!

Angular routerLink does not navigate to the corresponding component

Most of the time problem is a spelling mistake in

<a [routerLink]="['/home']" routerLinkActive="active">Home</a>

Just check again for spelling.

Nested attributes unpermitted parameters

From the docs

To whitelist an entire hash of parameters, the permit! method can be used

params.require(:log_entry).permit!

Nested attributes are in the form of a hash. In my app, I have a Question.rb model accept nested attributes for an Answer.rb model (where the user creates answer choices for a question he creates). In the questions_controller, I do this

  def question_params

      params.require(:question).permit!

  end

Everything in the question hash is permitted, including the nested answer attributes. This also works if the nested attributes are in the form of an array.

Having said that, I wonder if there's a security concern with this approach because it basically permits anything that's inside the hash without specifying exactly what it is, which seems contrary to the purpose of strong parameters.

how to use jQuery ajax calls with node.js

Thanks to yojimbo for his answer. To add to his sample, I wanted to use the jquery method $.getJSON which puts a random callback in the query string so I also wanted to parse that out in the Node.js. I also wanted to pass an object back and use the stringify function.

This is my Client Side code.

$.getJSON("http://localhost:8124/dummy?action=dostuff&callback=?",
function(data){
  alert(data);
},
function(jqXHR, textStatus, errorThrown) {
    alert('error ' + textStatus + " " + errorThrown);
});

This is my Server side Node.js

var http = require('http');
var querystring = require('querystring');
var url = require('url');

http.createServer(function (req, res) {
    //grab the callback from the query string   
    var pquery = querystring.parse(url.parse(req.url).query);   
    var callback = (pquery.callback ? pquery.callback : '');

    //we probably want to send an object back in response to the request
    var returnObject = {message: "Hello World!"};
    var returnObjectString = JSON.stringify(returnObject);

    //push back the response including the callback shenanigans
    res.writeHead(200, {'Content-Type': 'text/plain'});
    res.end(callback + '(\'' + returnObjectString + '\')');
}).listen(8124);

How to add elements of a Java8 stream into an existing List

targetList = sourceList.stream().flatmap(List::stream).collect(Collectors.toList());

Test method is inconclusive: Test wasn't run. Error?

This problem started when I upgraded to .NET Core 1.1.0

Solved by adding the following dependency to the project.json of the test project:

"Microsoft.DotNet.InternalAbstractions": "1.0.500-preview2-1-003177"

How to elegantly check if a number is within a range?

If it's to validate method parameters, none of the solutions throw ArgumentOutOfRangeException and allow easy/proper configuration of inclusive/exclusive min/max values.

Use like this

public void Start(int pos)
{
    pos.CheckRange(nameof(pos), min: 0);

    if (pos.IsInRange(max: 100, maxInclusive: false))
    {
        // ...
    }
}

I just wrote these beautiful functions. It also has the advantage of having no branching (a single if) for valid values. The hardest part is to craft the proper exception messages.

/// <summary>
/// Returns whether specified value is in valid range.
/// </summary>
/// <typeparam name="T">The type of data to validate.</typeparam>
/// <param name="value">The value to validate.</param>
/// <param name="min">The minimum valid value.</param>
/// <param name="minInclusive">Whether the minimum value is valid.</param>
/// <param name="max">The maximum valid value.</param>
/// <param name="maxInclusive">Whether the maximum value is valid.</param>
/// <returns>Whether the value is within range.</returns>
public static bool IsInRange<T>(this T value, T? min = null, bool minInclusive = true, T? max = null, bool maxInclusive = true)
    where T : struct, IComparable<T>
{
    var minValid = min == null || (minInclusive && value.CompareTo(min.Value) >= 0) || (!minInclusive && value.CompareTo(min.Value) > 0);
    var maxValid = max == null || (maxInclusive && value.CompareTo(max.Value) <= 0) || (!maxInclusive && value.CompareTo(max.Value) < 0);
    return minValid && maxValid;
}

/// <summary>
/// Validates whether specified value is in valid range, and throws an exception if out of range.
/// </summary>
/// <typeparam name="T">The type of data to validate.</typeparam>
/// <param name="value">The value to validate.</param>
/// <param name="name">The name of the parameter.</param>
/// <param name="min">The minimum valid value.</param>
/// <param name="minInclusive">Whether the minimum value is valid.</param>
/// <param name="max">The maximum valid value.</param>
/// <param name="maxInclusive">Whether the maximum value is valid.</param>
/// <returns>The value if valid.</returns>
public static T CheckRange<T>(this T value, string name, T? min = null, bool minInclusive = true, T? max = null, bool maxInclusive = true)
where T : struct, IComparable<T>
{
    if (!value.IsInRange(min, minInclusive, max, maxInclusive))
    {
        if (min.HasValue && minInclusive && max.HasValue && maxInclusive)
        {
            var message = "{0} must be between {1} and {2}.";
            throw new ArgumentOutOfRangeException(name, value, message.FormatInvariant(name, min, max));
        }
        else
        {
            var messageMin = min.HasValue ? GetOpText(true, minInclusive).FormatInvariant(min) : null;
            var messageMax = max.HasValue ? GetOpText(false, maxInclusive).FormatInvariant(max) : null;
            var message = (messageMin != null && messageMax != null) ?
                "{0} must be {1} and {2}." :
                "{0} must be {1}.";
            throw new ArgumentOutOfRangeException(name, value, message.FormatInvariant(name, messageMin ?? messageMax, messageMax));
        }
    }
    return value;
}

private static string GetOpText(bool greaterThan, bool inclusive)
{
    return (greaterThan && inclusive) ? "greater than or equal to {0}" :
        greaterThan ? "greater than {0}" :
        inclusive ? "less than or equal to {0}" :
        "less than {0}";
}

public static string FormatInvariant(this string format, params object?[] args) => string.Format(CultureInfo.InvariantCulture, format, args);

What does "exited with code 9009" mean during this build?

Actually I noticed that for some reason the %windir% environment variable sometimes get erased. What worked for me was re-set the windir environment variable to c:\windows, restart VS, and that's it. That way you prevent having to modify the solution files.

How can I open multiple files using "with open" in Python?

Since Python 3.3, you can use the class ExitStack from the contextlib module to safely
open an arbitrary number of files.

It can manage a dynamic number of context-aware objects, which means that it will prove especially useful if you don't know how many files you are going to handle.

In fact, the canonical use-case that is mentioned in the documentation is managing a dynamic number of files.

with ExitStack() as stack:
    files = [stack.enter_context(open(fname)) for fname in filenames]
    # All opened files will automatically be closed at the end of
    # the with statement, even if attempts to open files later
    # in the list raise an exception

If you are interested in the details, here is a generic example in order to explain how ExitStack operates:

from contextlib import ExitStack

class X:
    num = 1

    def __init__(self):
        self.num = X.num
        X.num += 1

    def __repr__(self):
        cls = type(self)
        return '{cls.__name__}{self.num}'.format(cls=cls, self=self)

    def __enter__(self):
        print('enter {!r}'.format(self))
        return self.num

    def __exit__(self, exc_type, exc_value, traceback):
        print('exit {!r}'.format(self))
        return True

xs = [X() for _ in range(3)]

with ExitStack() as stack:
    print(len(stack._exit_callbacks)) # number of callbacks called on exit
    nums = [stack.enter_context(x) for x in xs]
    print(len(stack._exit_callbacks))

print(len(stack._exit_callbacks))
print(nums)

Output:

0
enter X1
enter X2
enter X3
3
exit X3
exit X2
exit X1
0
[1, 2, 3]

Can I make dynamic styles in React Native?

You'll want something like this:

var RandomBgApp = React.createClass({
    render: function() {

        var getRandomColor = function() {
            var letters = '0123456789ABCDEF'.split('');
            var color = '#';
            for (var i = 0; i < 6; i++ ) {
                color += letters[Math.floor(Math.random() * 16)];
            }
            return color;
        };

        var rows = [
            { name: 'row 1'},
            { name: 'row 2'},
            { name: 'row 3'}
        ];

        var rowNodes = rows.map(function(row) {
            return <Text style={{backgroundColor:getRandomColor()}}>{row.name}</Text>
        });

        return (
            <View>
                {rowNodes}
            </View>
        );

    }
});

In this example I take the rows array, containing the data for the rows in the component, and map it into an array of Text components. I use inline styles to call the getRandomColor function every time I create a new Text component.

The issue with your code is that you define the style once and therefore getRandomColor only gets called once - when you define the style.

How to deal with http status codes other than 200 in Angular 2

Yes you can handle with the catch operator like this and show alert as you want but firstly you have to import Rxjs for the same like this way

import {Observable} from 'rxjs/Rx';

return this.http.request(new Request(this.requestoptions))
            .map((res: Response) => {
                if (res) {
                    if (res.status === 201) {
                        return [{ status: res.status, json: res }]
                    }
                    else if (res.status === 200) {
                        return [{ status: res.status, json: res }]
                    }
                }
            }).catch((error: any) => {
                if (error.status === 500) {
                    return Observable.throw(new Error(error.status));
                }
                else if (error.status === 400) {
                    return Observable.throw(new Error(error.status));
                }
                else if (error.status === 409) {
                    return Observable.throw(new Error(error.status));
                }
                else if (error.status === 406) {
                    return Observable.throw(new Error(error.status));
                }
            });
    }

also you can handel error (with err block) that is throw by catch block while .map function,

like this -

...
.subscribe(res=>{....}
           err => {//handel here});

Update

as required for any status without checking particluar one you can try this: -

return this.http.request(new Request(this.requestoptions))
            .map((res: Response) => {
                if (res) {
                    if (res.status === 201) {
                        return [{ status: res.status, json: res }]
                    }
                    else if (res.status === 200) {
                        return [{ status: res.status, json: res }]
                    }
                }
            }).catch((error: any) => {
                if (error.status < 400 ||  error.status ===500) {
                    return Observable.throw(new Error(error.status));
                }
            })
            .subscribe(res => {...},
                       err => {console.log(err)} );

Convert integer value to matching Java Enum

You will have to make a new static method where you iterate PcapLinkType.values() and compare:

public static PcapLinkType forCode(int code) {
    for (PcapLinkType typ? : PcapLinkType.values()) {
        if (type.getValue() == code) {
            return type;
        }
    }
    return null;
 }

That would be fine if it is called rarely. If it is called frequently, then look at the Map optimization suggested by others.

How to unset (remove) a collection element after fetching it?

Laravel Collection implements the PHP ArrayAccess interface (which is why using foreach is possible in the first place).

If you have the key already you can just use PHP unset.

I prefer this, because it clearly modifies the collection in place, and is easy to remember.

foreach ($collection as $key => $value) {
    unset($collection[$key]);
}

How can I check MySQL engine type for a specific table?

If you are a GUI guy and just want to find it in PhpMyAdmin, than pick the table of your choice and head over the Operations tab >> Table options >> Storage Engine. You can even change it from there using the drop-down options list.

PS: This guide is based on version 4.8 of PhpMyAdmin. Can't guarantee the same path for very older versions.

Is there a rule-of-thumb for how to divide a dataset into training and validation sets?

Well, you should think about one more thing.

If you have a really big dataset, like 1,000,000 examples, split 80/10/10 may be unnecessary, because 10% = 100,000 examples may be just too much for just saying that model works fine.

Maybe 99/0.5/0.5 is enough because 5,000 examples can represent most of the variance in your data and you can easily tell that model works good based on these 5,000 examples in test and dev.

Don't use 80/20 just because you've heard it's ok. Think about the purpose of the test set.

Better way to convert file sizes in Python

Here's a version that matches the output of ls -lh.

def human_size(num: int) -> str:
    base = 1
    for unit in ['B', 'K', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y']:
        n = num / base
        if n < 9.95 and unit != 'B':
            # Less than 10 then keep 1 decimal place
            value = "{:.1f}{}".format(n, unit)
            return value
        if round(n) < 1000:
            # Less than 4 digits so use this
            value = "{}{}".format(round(n), unit)
            return value
        base *= 1024
    value = "{}{}".format(round(n), unit)
    return value

Bootstrap datepicker disabling past dates without current date

Try it :

$(function () {
     $('#datetimepicker').datetimepicker({  minDate:new Date()});
});

Why is it said that "HTTP is a stateless protocol"?

Modern HTTP is stateful. Old timey HTTP was stateless.

Before Netscape invented cookies and HTTPS in 1994 http could be considered stateless. As time progressed more and more stateful aspects were added for a myriad of reasons, including performance and security.

While HTTP 1 originally sought out to be stateless many HTTP/2 components are the very definition of stateful. HTTP/2 abandoned stateless goals.

No reasonable person can read the HTTP/2 RFC and think it is stateless. The errant "HTTP is stateless" old time dogma is false and far from the current reality of stateful HTTP.

Here's a limited, and not exhaustive list, of stateful HTTP/1 and HTTP/2 components:

  • Cookies, named "HTTP State Management Mechanism" by the RFC.
  • HTTPS, which stores keys thus state.
  • HTTP authentication requires state.
  • Web Storage.
  • HTTP caching is stateful.
  • The very purpose of the stream identifier is state. It's even in the name of the RFC section, "Stream States".
  • Header blocks, which establish stream identifiers, are stateful.
  • Frames which reference stream identifiers are stateful.
  • Header Compression, which the HTTP RFC explicitly says is stateful, is stateful.
  • Opportunistic encryption is stateful.

Section 5.1 of the HTTP/2 RFC is a great example of stateful mechanisms defined by the HTTP/2 standard.

Is it safe for web applications to consider HTTP/2 as a stateless protocol?

HTTP/2 is a stateful protocol, but that doesn't mean your HTTP/2 application can't be stateless. You can choose to not use certain stateful features for stateless HTTP/2 applications by using only a subset of HTTP/2 features.

Cookies and some other stateful mechanisms, or less obvious stateful mechanisms, are later HTTP additions. HTTP 1 is said to be stateless although in practice we use standardized stateful mechanisms, like cookies, TLS, and caching. Unlike HTTP/1, HTTP/2 defines stateful components in its standard from the very beginning. A particular HTTP/2 application can use a subset of HTTP/2 features to maintain statelessness, but the protocol itself anticipate state to be the norm, not the exception.

Existing applications, even HTTP 1 applications, needing state will break if trying to use them statelessly. It can be impossible to log into some HTTP/1.1 websites if cookies are disabled, thus breaking the application. It may not be safe to assume that a particular HTTP 1 application does not use state. This is no different for HTTP/2.

Say it with me one last time:

HTTP/2 is a stateful protocol.

You have not concluded your merge (MERGE_HEAD exists)

OK. The problem is your previous pull failed to merge automatically and went to conflict state. And the conflict wasn't resolved properly before the next pull.

  1. Undo the merge and pull again.

    To undo a merge:

    git merge --abort [Since git version 1.7.4]

    git reset --merge [prior git versions]

  2. Resolve the conflict.

  3. Don't forget to add and commit the merge.

  4. git pull now should work fine.

Eclipse Problems View not showing Errors anymore

  1. Check your source directory is listed in source folder of project

    • Right-click your project > Build Path > Configure Build Path > Source.
  2. If you are using multiple projects (as dependencies)

    • Project->Clean...,

      enter image description here
  3. Check "Build Automatically" is enabled or not.

    • project > Build Automatically

      enter image description here

SQLAlchemy default DateTime

DateTime doesn't have a default key as an input. The default key should be an input to the Column function. Try this:

import datetime
from sqlalchemy import Column, Integer, DateTime
from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

class Test(Base):
    __tablename__ = 'test'

    id = Column(Integer, primary_key=True)
    created_date = Column(DateTime, default=datetime.datetime.utcnow)

Start systemd service after specific service?

After= dependency is only effective when service including After= and service included by After= are both scheduled to start as part of your boot up.

Ex:

a.service
[Unit]
After=b.service

This way, if both a.service and b.service are enabled, then systemd will order b.service after a.service.

If I am not misunderstanding, what you are asking is how to start b.service when a.service starts even though b.service is not enabled.

The directive for this is Wants= or Requires= under [Unit].

website.service
[Unit]
Wants=mongodb.service
After=mongodb.service

The difference between Wants= and Requires= is that with Requires=, a failure to start b.service will cause the startup of a.service to fail, whereas with Wants=, a.service will start even if b.service fails. This is explained in detail on the man page of .unit.

JavaScript - XMLHttpRequest, Access-Control-Allow-Origin errors

I've gotten same problem. The servers logs showed:

DEBUG: <-- origin: null

I've investigated that and it occurred that this is not populated when I've been calling from file from local drive. When I've copied file to the server and used it from server - the request worked perfectly fine

jQuery $.ajax(), $.post sending "OPTIONS" as REQUEST_METHOD in Firefox

Another possibility to circumvent the problem is to use a proxy script. That method is described for example here

How do I access my webcam in Python?

gstreamer can handle webcam input. If I remeber well, there are python bindings for it!

Creating a config file in PHP

Well - it would be sort of difficult to store your database configuration data in a database - don't ya think?

But really, this is a pretty heavily opinionated question because any style works really and it's all a matter of preference. Personally, I'd go for a configuration variable rather than constants - generally because I don't like things in the global space unless necessary. None of the functions in my codebase should be able to easily access my database password (except my database connection logic) - so I'd use it there and then likely destroy it.

Edit: to answer your comment - none of the parsing mechanisms would be the fastest (ini, json, etc) - but they're also not the parts of your application that you'd really need to focus on optimizing since the speed difference would be negligible on such small files.

R command for setting working directory to source file location in Rstudio

Here is another way to do it:

set2 <- function(name=NULL) {
  wd <- rstudioapi::getSourceEditorContext()$path
  if (!is.null(name)) {
    if (substr(name, nchar(name) - 1, nchar(name)) != '.R') 
      name <- paste0(name, '.R')
  }
  else {
    name <- stringr::word(wd, -1, sep='/')
  }
  wd <- gsub(wd, pattern=paste0('/', name), replacement = '')
  no_print <- eval(expr=setwd(wd), envir = .GlobalEnv)
}
set2()

X-Frame-Options: ALLOW-FROM in firefox and chrome

ALLOW-FROM is not supported in Chrome or Safari. See MDN article: https://developer.mozilla.org/en-US/docs/Web/HTTP/X-Frame-Options

You are already doing the work to make a custom header and send it with the correct data, can you not just exclude the header when you detect it is from a valid partner and add DENY to every other request? I don't see the benefit of AllowFrom when you are already dynamically building the logic up?

How to Identify Microsoft Edge browser via CSS?

/* Microsoft Edge Browser 12-18 (All versions before Chromium) - one-liner method */

_:-ms-lang(x), _:-webkit-full-screen, .selector { property:value; }

That works great!

// for instance:
_:-ms-lang(x), _:-webkit-full-screen, .headerClass 
{ 
  border: 1px solid brown;
}

https://jeffclayton.wordpress.com/2015/04/07/css-hacks-for-windows-10-and-spartan-browser-preview/

jQuery get specific option tag text

  1. If there is only one select tag in on the page then you can specify select inside of id 'list'

    jQuery("select option[value=2]").text();
    
  2. To get selected text

    jQuery("select option:selected").text();
    

Name attribute in @Entity and @Table

@Entity(name = "someThing") => this name will be used to identify the domain ..this name will only be identified by hql queries ..ie ..name of the domain object

@Table(name = "someThing") => this name will be used to which table referred by domain object..ie ..name of the table

How to get Current Timestamp from Carbon in Laravel 5

You can try this if you want date time string:

use Carbon\Carbon;
$current_date_time = Carbon::now()->toDateTimeString(); // Produces something like "2019-03-11 12:25:00"

If you want timestamp, you can try:

use Carbon\Carbon;
$current_timestamp = Carbon::now()->timestamp; // Produces something like 1552296328

See the official Carbon documentation here.

Convert UTC dates to local time in PHP

Answer

Convert the UTC datetime to America/Denver

// create a $dt object with the UTC timezone
$dt = new DateTime('2016-12-12 12:12:12', new DateTimeZone('UTC'));

// change the timezone of the object without changing it's time
$dt->setTimezone(new DateTimeZone('America/Denver'));

// format the datetime
$dt->format('Y-m-d H:i:s T');

Notes

time() returns the unix timestamp, which is a number, it has no timezone.

date('Y-m-d H:i:s T') returns the date in the current locale timezone.

gmdate('Y-m-d H:i:s T') returns the date in UTC

date_default_timezone_set() changes the current locale timezone

to change a time in a timezone

// create a $dt object with the America/Denver timezone
$dt = new DateTime('2016-12-12 12:12:12', new DateTimeZone('America/Denver'));

// change the timezone of the object without changing it's time
$dt->setTimezone(new DateTimeZone('UTC'));

// format the datetime
$dt->format('Y-m-d H:i:s T');

here you can see all the available timezones

https://en.wikipedia.org/wiki/List_of_tz_database_time_zones

here are all the formatting options

http://php.net/manual/en/function.date.php

Update PHP timezone DB (in linux)

sudo pecl install timezonedb

JNZ & CMP Assembly Instructions

JNZ is short for "Jump if not zero (ZF = 0)", and NOT "Jump if the ZF is set".

If it's any easier to remember, consider that JNZ and JNE (jump if not equal) are equivalent. Therefore, when you're doing cmp al, 47 and the content of AL is equal to 47, the ZF is set, ergo the jump (if Not Equal - JNE) should not be taken.

Add A Year To Today's Date

    var d = new Date();
    var year = d.getFullYear();
    var month = d.getMonth();
    var day = d.getDate();

    var fulldate = new Date(year + 1, month, day);

    var toDate = fulldate.toISOString().slice(0, 10);

    $("#txtToDate").val(toDate);

    output : 2020-01-02

Have a reloadData for a UITableView animate when changing

The way to approach this is to tell the tableView to remove and add rows and sections with the

insertRowsAtIndexPaths:withRowAnimation:,
deleteRowsAtIndexPaths:withRowAnimation:,
insertSections:withRowAnimation: and
deleteSections:withRowAnimation:

methods of UITableView.

When you call these methods, the table will animate in/out the items you requested, then call reloadData on itself so you can update the state after this animation. This part is important - if you animate away everything but don't change the data returned by the table's dataSource, the rows will appear again after the animation completes.

So, your application flow would be:

[self setTableIsInSecondState:YES];

[myTable deleteSections:[NSIndexSet indexSetWithIndex:0] withRowAnimation:YES]];

As long as your table's dataSource methods return the correct new set of sections and rows by checking [self tableIsInSecondState] (or whatever), this will achieve the effect you're looking for.

ActiveRecord find and only return selected columns

In Rails 2

l = Location.find(:id => id, :select => "name, website, city", :limit => 1)

...or...

l = Location.find_by_sql(:conditions => ["SELECT name, website, city FROM locations WHERE id = ? LIMIT 1", id])

This reference doc gives you the entire list of options you can use with .find, including how to limit by number, id, or any other arbitrary column/constraint.

In Rails 3 w/ActiveRecord Query Interface

l = Location.where(["id = ?", id]).select("name, website, city").first

Ref: Active Record Query Interface

You can also swap the order of these chained calls, doing .select(...).where(...).first - all these calls do is construct the SQL query and then send it off.

Convert time in HH:MM:SS format to seconds only?

<?php
$time    = '21:32:32';
$seconds = 0;
$parts   = explode(':', $time);

if (count($parts) > 2) {
    $seconds += $parts[0] * 3600;
}
$seconds += $parts[1] * 60;
$seconds += $parts[2];

Global npm install location on windows?

These are typical npm paths if you install a package globally:

Windows XP -             %USERPROFILE%\Application Data\npm\node_modules
Newer Windows Versions - %AppData%\npm\node_modules
or -                     %AppData%\roaming\npm\node_modules

Why is it bad practice to call System.gc()?

In my experience, using System.gc() is effectively a platform-specific form of optimization (where "platform" is the combination of hardware architecture, OS, JVM version and possible more runtime parameters such as RAM available), because its behaviour, while roughly predictable on a specific platform, can (and will) vary considerably between platforms.

Yes, there are situations where System.gc() will improve (perceived) performance. On example is if delays are tolerable in some parts of your app, but not in others (the game example cited above, where you want GC to happen at the start of a level, not during the level).

However, whether it will help or hurt (or do nothing) is highly dependent on the platform (as defined above).

So I think it is valid as a last-resort platform-specific optimization (i.e. if other performance optimizations are not enough). But you should never call it just because you believe it might help(without specific benchmarks), because chances are it will not.

Change jsp on button click

Just use two forms.

In the first form action attribute will have name of the second jdp page and your 1st button. In the second form there will be 2nd button with action attribute thats giving the name of your 3rd jsp page.

It will be like this :

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
    <form name="main1"  method="get" action="2nd.jsp">
        <input type="submit" name="ter" value="LOGOUT" >
    </form>
    <DIV ALIGN="left"><form name="main0" action="3rd.jsp" method="get">
        <input type="submit" value="FEEDBACK">
    </form></DIV>
</body>
</html>

Android map v2 zoom to show all the markers

   //For adding a marker in Google map
        MarkerOptions mp = new MarkerOptions();
        mp.position(new LatLng(Double.parseDouble(latitude), Double.parseDouble(longitude)));
        mp.snippet(strAddress);
        map.addMarker(mp);

        try {

            b = new LatLngBounds.Builder();

            if (MapDetailsList.list != null && MapDetailsList.list.size() > 0) {

                for (int i = 0; i < MapDetailsList.list.size(); i++) {

                    b.include(new LatLng(Double.parseDouble(MapDetailsList.list.get(i).getLatitude()),
                            Double.parseDouble(MapDetailsList.list.get(i).getLongitude())));

                }
                LatLngBounds bounds = b.build();

                DisplayMetrics displayMetrics = getResources().getDisplayMetrics();
                int width = displayMetrics.widthPixels;
                int height = displayMetrics.heightPixels;

                // Change the padding as per needed
                CameraUpdate cu = CameraUpdateFactory.newLatLngBounds(bounds, width-200, height-200, 5);
                // map.setCenter(bounds.getCenter());

                map.animateCamera(cu);

            }

        } catch (Exception e) {

        }

http://i64.tinypic.com/2qjybh4.png

http://i63.tinypic.com/flzwus.png

http://i63.tinypic.com/112g5fm.png

Google Map API - Removing Markers

You can try this

    markers[markers.length-1].setMap(null);

Hope it works.

Cause of No suitable driver found for

"no suitable driver" usually means that the syntax for the connection URL is incorrect.

Set Jackson Timezone for Date deserialization

I had same problem with Calendar deserialization, solved extending CalendarDeserializer.
It forces UTC Timezone
I paste the code if someone need it:

@JacksonStdImpl
public class UtcCalendarDeserializer extends CalendarDeserializer {

    TimeZone TZ_UTC = TimeZone.getTimeZone("UTC");

    @Override
    public Calendar deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException, JsonProcessingException {
        JsonToken t = jp.getCurrentToken();
        if (t == JsonToken.VALUE_NUMBER_INT) {
            Calendar cal = Calendar.getInstance(TZ_UTC);
            cal.clear();
            cal.setTimeInMillis(jp.getLongValue());

            return cal;
        }

        return super.deserialize(jp, ctxt);
    }
}

in JSON model class just annotate the field with:

@JsonDeserialize(using = UtcCalendarDeserializer.class)
private Calendar myCalendar;

create unique id with javascript

There are two packages available for this.

  • For short unique id generation nanoid link
import { nanoid } from 'nanoid'
const id = nanoid()    // "Uakgb_J5m9g-0JDMbcJqLJ"
const id = nanoid(10)  // "jcNqc0UAWK"
  • For universally unique id generation uuid link
import { v4 as uuidv4 } from 'uuid';
const id= uuidv4();    // quite big id

POI setting Cell Background to a Custom Color

See http://poi.apache.org/spreadsheet/quick-guide.html#CustomColors.

Custom colors

HSSF:

HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet();
HSSFRow row = sheet.createRow((short) 0);
HSSFCell cell = row.createCell((short) 0);
cell.setCellValue("Default Palette");

//apply some colors from the standard palette,
// as in the previous examples.
//we'll use red text on a lime background

HSSFCellStyle style = wb.createCellStyle();
style.setFillForegroundColor(HSSFColor.LIME.index);
style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);

HSSFFont font = wb.createFont();
font.setColor(HSSFColor.RED.index);
style.setFont(font);

cell.setCellStyle(style);

//save with the default palette
FileOutputStream out = new FileOutputStream("default_palette.xls");
wb.write(out);
out.close();

//now, let's replace RED and LIME in the palette
// with a more attractive combination
// (lovingly borrowed from freebsd.org)

cell.setCellValue("Modified Palette");

//creating a custom palette for the workbook
HSSFPalette palette = wb.getCustomPalette();

//replacing the standard red with freebsd.org red
palette.setColorAtIndex(HSSFColor.RED.index,
        (byte) 153,  //RGB red (0-255)
        (byte) 0,    //RGB green
        (byte) 0     //RGB blue
);
//replacing lime with freebsd.org gold
palette.setColorAtIndex(HSSFColor.LIME.index, (byte) 255, (byte) 204, (byte) 102);

//save with the modified palette
// note that wherever we have previously used RED or LIME, the
// new colors magically appear
out = new FileOutputStream("modified_palette.xls");
wb.write(out);
out.close();

XSSF:

XSSFWorkbook wb = new XSSFWorkbook();
XSSFSheet sheet = wb.createSheet();
XSSFRow row = sheet.createRow(0);
XSSFCell cell = row.createCell( 0);
cell.setCellValue("custom XSSF colors");

XSSFCellStyle style1 = wb.createCellStyle();
style1.setFillForegroundColor(new XSSFColor(new java.awt.Color(128, 0, 128)));
style1.setFillPattern(CellStyle.SOLID_FOREGROUND);

JavaScript - cannot set property of undefined

you never set d[a] to any value.

Because of this, d[a] evaluates to undefined, and you can't set properties on undefined.

If you add d[a] = {} right after d = {} things should work as expected.

Alternatively, you could use an object initializer:

d[a] = {
    greetings: b,
    data: c
};

Or you could set all the properties of d in an anonymous function instance:

d = new function () {
    this[a] = {
        greetings: b,
        data: c
    };
};

If you're in an environment that supports ES2015 features, you can use computed property names:

d = {
  [a]: {
    greetings: b,
    data: c
  }
};

Specifying Font and Size in HTML table

The font tag has been deprecated for some time now.

That being said, the reason why both of your tables display with the same font size is that the 'size' attribute only accepts values ranging from 1 - 7. The smallest size is 1. The largest size is 7. The default size is 3. Any values larger than 7 will just display the same as if you had used 7, because 7 is the maximum value allowed.

And as @Alex H said, you should be using CSS for this.

Simple dynamic breadcrumb

Also made a little script using RDFa (you can also use microdata or other formats) Check it out on google This script also keeps in mind your site structure.

function breadcrumbs($text = 'You are here: ', $sep = ' &raquo; ', $home = 'Home') {
//Use RDFa breadcrumb, can also be used for microformats etc.
$bc     =   '<div xmlns:v="http://rdf.data-vocabulary.org/#" id="crums">'.$text;
//Get the website:
$site   =   'http://'.$_SERVER['HTTP_HOST'];
//Get all vars en skip the empty ones
$crumbs =   array_filter( explode("/",$_SERVER["REQUEST_URI"]) );
//Create the home breadcrumb
$bc    .=   '<span typeof="v:Breadcrumb"><a href="'.$site.'" rel="v:url" property="v:title">'.$home.'</a>'.$sep.'</span>'; 
//Count all not empty breadcrumbs
$nm     =   count($crumbs);
$i      =   1;
//Loop the crumbs
foreach($crumbs as $crumb){
    //Make the link look nice
    $link    =  ucfirst( str_replace( array(".php","-","_"), array(""," "," ") ,$crumb) );
    //Loose the last seperator
    $sep     =  $i==$nm?'':$sep;
    //Add crumbs to the root
    $site   .=  '/'.$crumb;
    //Make the next crumb
    $bc     .=  '<span typeof="v:Breadcrumb"><a href="'.$site.'" rel="v:url" property="v:title">'.$link.'</a>'.$sep.'</span>';
    $i++;
}
$bc .=  '</div>';
//Return the result
return $bc;}

Installing Java on OS X 10.9 (Mavericks)

This error means Java is not properly installed .

1) brew cask install java (No need to install cask separately it comes with brew)

2) java -version

java version "1.8.0_131"
Java(TM) SE Runtime Environment (build 1.8.0_131-b11)

P.S - What is brew-cask ? Homebrew-Cask extends Homebrew , and solves the hassle of executing an extra command - “To install, drag this icon…” after installing a Application using Homebrew.

N.B - This problem is not specific to Mavericks , you will get it almost all the OS X, including EL Capitan.

Can I display the value of an enum with printf()?

As a string, no. As an integer, %d.

Unless you count:

static char* enumStrings[] = { /* filler 0's to get to the first value, */
                               "enum0", "enum1", 
                               /* filler for hole in the middle: ,0 */
                               "enum2", "enum3", .... };

...

printf("The value is %s\n", enumStrings[thevalue]);

This won't work for something like an enum of bit masks. At that point, you need a hash table or some other more elaborate data structure.

Add new value to an existing array in JavaScript

You don't need jQuery for that. Use regular javascript

var arr = new Array();
// or var arr = [];
arr.push('value1');
arr.push('value2');

Note: In javascript, you can also use Objects as Arrays, but still have access to the Array prototypes. This makes the object behave like an array:

var obj = new Object();
Array.prototype.push.call(obj, 'value');

will create an object that looks like:

{
    0: 'value',
    length: 1
}

You can access the vaules just like a normal array f.ex obj[0].

Bypass invalid SSL certificate errors when calling web services in .Net

I was having same error using DownloadString; and was able to make it works as below with suggestions on this page

System.Net.WebClient client = new System.Net.WebClient();            
ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };
string sHttpResonse = client.DownloadString(sUrl);

Initializing default values in a struct

You can do it by using a constructor, like this:

struct Date
{
int day;
int month;
int year;

Date()
{
    day=0;
    month=0;
    year=0;
}
};

or like this:

struct Date
{
int day;
int month;
int year;

Date():day(0),
       month(0),
       year(0){}
};

In your case bar.c is undefined,and its value depends on the compiler (while a and b were set to true).

Javascript: Call a function after specific time period

Timeout:

setTimeout(() => {
   console.log('Hello Timeout!')
}, 3000);

Interval:

setInterval(() => {
   console.log('Hello Interval!')
}, 2000);

Call a function after previous function is complete

This answer uses promises, a JavaScript feature of the ECMAScript 6 standard. If your target platform does not support promises, polyfill it with PromiseJs.

Promises are a new (and a lot better) way to handle asynchronous operations in JavaScript:

$('a.button').click(function(){
    if (condition == 'true'){
        function1(someVariable).then(function() {
            //this function is executed after function1
            function2(someOtherVariable);
        });
    }
    else {
        doThis(someVariable);
    }
});


function function1(param, callback) {
    return new Promise(function (fulfill, reject){
        //do stuff
        fulfill(result); //if the action succeeded
        reject(error); //if the action did not succeed
    });
} 

This may seem like a significant overhead for this simple example, but for more complex code it is far better than using callbacks. You can easily chain multiple asynchronous calls using multiple then statements:

function1(someVariable).then(function() {
    function2(someOtherVariable);
}).then(function() {
    function3();
});

You can also wrap jQuery deferrds easily (which are returned from $.ajax calls):

Promise.resolve($.ajax(...params...)).then(function(result) {
    //whatever you want to do after the request
});

As @charlietfl noted, the jqXHR object returned by $.ajax() implements the Promise interface. So it is not actually necessary to wrap it in a Promise, it can be used directly:

$.ajax(...params...).then(function(result) {
    //whatever you want to do after the request
});

How to get string objects instead of Unicode from JSON?

So, I've run into the same problem. Guess what was the first Google result.

Because I need to pass all data to PyGTK, unicode strings aren't very useful to me either. So I have another recursive conversion method. It's actually also needed for typesafe JSON conversion - json.dump() would bail on any non-literals, like Python objects. Doesn't convert dict indexes though.

# removes any objects, turns unicode back into str
def filter_data(obj):
        if type(obj) in (int, float, str, bool):
                return obj
        elif type(obj) == unicode:
                return str(obj)
        elif type(obj) in (list, tuple, set):
                obj = list(obj)
                for i,v in enumerate(obj):
                        obj[i] = filter_data(v)
        elif type(obj) == dict:
                for i,v in obj.iteritems():
                        obj[i] = filter_data(v)
        else:
                print "invalid object in data, converting to string"
                obj = str(obj) 
        return obj

Why does make think the target is up to date?

EDIT: This only applies to some versions of make - you should check your man page.

You can also pass the -B flag to make. As per the man page, this does:

-B, --always-make Unconditionally make all targets.

So make -B test would solve your problem if you were in a situation where you don't want to edit the Makefile or change the name of your test folder.

How to get a Static property with Reflection

Ok so the key for me was to use the .FlattenHierarchy BindingFlag. I don't really know why I just added it on a hunch and it started working. So the final solution that allows me to get Public Instance or Static Properties is:

obj.GetType.GetProperty(propName, Reflection.BindingFlags.Public _
  Or Reflection.BindingFlags.Static Or Reflection.BindingFlags.Instance Or _
  Reflection.BindingFlags.FlattenHierarchy)

swift UITableView set rowHeight

Make sure Your TableView Delegate are working as well. if not then in your story board or in .xib press and hold Control + right click on tableView drag and Drop to your Current ViewController. swift 2.0

func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
    return 60.0;
}

How to convert between bytes and strings in Python 3?

In python3, there is a bytes() method that is in the same format as encode().

str1 = b'hello world'
str2 = bytes("hello world", encoding="UTF-8")
print(str1 == str2) # Returns True

I didn't read anything about this in the docs, but perhaps I wasn't looking in the right place. This way you can explicitly turn strings into byte streams and have it more readable than using encode and decode, and without having to prefex b in front of quotes.

Best Timer for using in a Windows service

I agree with previous comment that might be best to consider a different approach. My suggest would be write a console application and use the windows scheduler:

This will:

  • Reduce plumbing code that replicates scheduler behaviour
  • Provide greater flexibility in terms of scheduling behaviour (e.g. only run on weekends) with all scheduling logic abstracted from application code
  • Utilise the command line arguments for parameters without having to setup configuration values in config files etc
  • Far easier to debug/test during development
  • Allow a support user to execute by invoking the console application directly (e.g. useful during support situations)

Center align with table-cell

Here is a good starting point.

HTML:

<div class="containing-table">
    <div class="centre-align">
        <div class="content"></div>
    </div>
</div>

CSS:

.containing-table {
    display: table;
    width: 100%;
    height: 400px; /* for demo only */
    border: 1px dotted blue;
}
.centre-align {
    padding: 10px;
    border: 1px dashed gray;
    display: table-cell;
    text-align: center;
    vertical-align: middle;
}
.content {
    width: 50px;
    height: 50px;
    background-color: red;
    display: inline-block;
    vertical-align: top; /* Removes the extra white space below the baseline */
}

See demo at: http://jsfiddle.net/audetwebdesign/jSVyY/

.containing-table establishes the width and height context for .centre-align (the table-cell).

You can apply text-align and vertical-align to alter .centre-align as needed.

Note that .content needs to use display: inline-block if it is to be centered horizontally using the text-align property.

Multiple connections to a server or shared resource by the same user, using more than one user name, are not allowed

It may be that the Windows Credential Manager is holding onto credentials for the network share.

Credential Manager - Windows Credentials

Load up Credential Manager (the easiest way is perhaps just to Search for that in the Start Menu), see if there are any Windows Credentials for your network share, and try deleting/updating them.

Date Conversion from String to sql Date in Java giving different output?

That is the simple way of converting string into util date and sql date

String startDate="12-31-2014";
SimpleDateFormat sdf1 = new SimpleDateFormat("MM-dd-yyyy");
java.util.Date date = sdf1.parse(startDate);
java.sql.Date sqlStartDate = new java.sql.Date(date.getTime()); 

Changing the interval of SetInterval while it's running

I'm a beginner in javascript, and didn't found any help in the previous answers (but many good ideas).
This piece of code below accelerates (acceleration > 1) or decelerates (acceleration <1). I hope it might help some people:

function accelerate(yourfunction, timer, refresh, acceleration) {
    var new_timer = timer / acceleration;
    var refresh_init = refresh;//save this user defined value
    if (refresh < new_timer ){//avoid reseting the interval before it has produced anything.
        refresh = new_timer + 1 ;
    };
    var lastInter = setInterval(yourfunction, new_timer);
    console.log("timer:", new_timer);
    function stopLastInter() {
        clearInterval(lastInter);
        accelerate(yourfunction, new_timer, refresh_init, acceleration);
        console.log("refresh:", refresh);
    };
    setTimeout(stopLastInter, refresh);
}

With :

  • timer: the setInterval initial value in ms (increasing or decreasing)
  • refresh: the time before a new value of timer is calculated. This is the step lenght
  • factor: the gap between the old and the next timer value. This is the step height

RandomForestClassfier.fit(): ValueError: could not convert string to float

You may not pass str to fit this kind of classifier.

For example, if you have a feature column named 'grade' which has 3 different grades:

A,B and C.

you have to transfer those str "A","B","C" to matrix by encoder like the following:

A = [1,0,0]

B = [0,1,0]

C = [0,0,1]

because the str does not have numerical meaning for the classifier.

In scikit-learn, OneHotEncoder and LabelEncoder are available in inpreprocessing module. However OneHotEncoder does not support to fit_transform() of string. "ValueError: could not convert string to float" may happen during transform.

You may use LabelEncoder to transfer from str to continuous numerical values. Then you are able to transfer by OneHotEncoder as you wish.

In the Pandas dataframe, I have to encode all the data which are categorized to dtype:object. The following code works for me and I hope this will help you.

 from sklearn import preprocessing
    le = preprocessing.LabelEncoder()
    for column_name in train_data.columns:
        if train_data[column_name].dtype == object:
            train_data[column_name] = le.fit_transform(train_data[column_name])
        else:
            pass

How to break lines in PowerShell?

Try "`n" with double quotes. (not single quotes '`n' )

For a complete list of escaping characters see:

Help about_Escape_character

The code should be

$str += "`n"

Go install fails with error: no install location for directory xxx outside GOPATH

In my case (OS X) it was because I have set GOPATH to /home/username/go (as per the book) instead of /Users/username/go

.jar error - could not find or load main class

You can always run this:

java -cp HelloWorld.jar HelloWorld

-cp HelloWorld.jar adds the jar to the classpath, then HelloWorld runs the class you wrote.

To create a runnable jar with a main class with no package, add Class-Path: . to the manifest:

Manifest-Version: 1.0
Class-Path: .
Main-Class: HelloWorld

I would advise using a package to give your class its own namespace. E.g.

package com.stackoverflow.user.blrp;

public class HelloWorld {
    ...
}

php Replacing multiple spaces with a single space

$output = preg_replace('/\s+/', ' ',$input);

\s is shorthand for [ \t\n\r]. Multiple spaces will be replaced with single space.

Apply formula to the entire column

Found another solution:

  • Apply the formula to the first 3 or 4 cells of the column
  • Ctrl + C the formula in one of the last rows (if you copy the first line it won't work)
  • Click on the column header to select the whole column
  • Press Ctrl + V to paste it in all cells bellow

For loop in Objective-C

You mean fast enumeration? You question is very unclear.

A normal for loop would look a bit like this:

unsigned int i, cnt = [someArray count];
for(i = 0; i < cnt; i++)
{ 
   // do loop stuff
   id someObject = [someArray objectAtIndex:i];
}

And a loop with fast enumeration, which is optimized by the compiler, would look like this:

for(id someObject in someArray)
{
   // do stuff with object
}

Keep in mind that you cannot change the array you are using in fast enumeration, thus no deleting nor adding when using fast enumeration

What is the correct value for the disabled attribute?

  • For XHTML, <input type="text" disabled="disabled" /> is the valid markup.
  • For HTML5, <input type="text" disabled /> is valid and used by W3C on their samples.
  • In fact, both ways works on all major browsers.

Actual meaning of 'shell=True' in subprocess

An example where things could go wrong with Shell=True is shown here

>>> from subprocess import call
>>> filename = input("What file would you like to display?\n")
What file would you like to display?
non_existent; rm -rf / # THIS WILL DELETE EVERYTHING IN ROOT PARTITION!!!
>>> call("cat " + filename, shell=True) # Uh-oh. This will end badly...

Check the doc here: subprocess.call()

Insert using LEFT JOIN and INNER JOIN

you can't use VALUES clause when inserting data using another SELECT query. see INSERT SYNTAX

INSERT INTO user
(
 id, name, username, email, opted_in
)
(
    SELECT id, name, username, email, opted_in
    FROM user
         LEFT JOIN user_permission AS userPerm
            ON user.id = userPerm.user_id
);

jQuery multiple conditions within if statement

i == 'InvKey' && i == 'PostDate' will never be true, since i can never equal two different things at once.

You're probably trying to write

if (i !== 'InvKey' && i !== 'PostDate')) 

How to convert a date to milliseconds

The SimpleDateFormat class allows you to parse a String into a java.util.Date object. Once you have the Date object, you can get the milliseconds since the epoch by calling Date.getTime().

The full example:

String myDate = "2014/10/29 18:10:45";
//creates a formatter that parses the date in the given format
SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Date date = sdf.parse(myDate);
long timeInMillis = date.getTime();

Note that this gives you a long and not a double, but I think that's probably what you intended. The documentation for the SimpleDateFormat class has tons on information on how to set it up to parse different formats.

How to get the azure account tenant Id?

My team really got sick of trying to find the tenant ID for our O365 and Azure projects. The devs, the support team, the sales team, everyone needs it at some point and never remembers how to do it.

So we've built this small site in the same vein as whatismyip.com. Hope you find it useful!

How to find my Microsoft 365, Azure or SharePoint Online tenant ID?

How to solve ERR_CONNECTION_REFUSED when trying to connect to localhost running IISExpress - Error 502 (Cannot debug from Visual Studio)?

I recently encounter this issue when I copy the source code from another machine.

-> Delete the .vs folder (it is hidden folder, so make sure you have enable view hidden folder option)
-> open visual studio and build your project. Visual studio will create new .vs folder as per current system configuration

What is a View in Oracle?

If you like the idea of Views, but are worried about performance you can get Oracle to create a cached table representing the view which oracle keeps up to date.
See materialized views

MySQL/SQL: Group by date only on a Datetime column

Or:

SELECT SUM(foo), DATE(mydate) mydate FROM a_table GROUP BY mydate;

More efficient (I think.) Because you don't have to cast mydate twice per row.

How to normalize a signal to zero mean and unit variance?

It seems like you are essentially looking into computing the z-score or standard score of your data, which is calculated through the formula: z = (x-mean(x))/std(x)

This should work:

%% Original data (Normal with mean 1 and standard deviation 2)
x = 1 + 2*randn(100,1);
mean(x)
var(x)
std(x)

%% Normalized data with mean 0 and variance 1
z = (x-mean(x))/std(x);
mean(z)
var(z)
std(z)

How to send a compressed archive that contains executables so that Google's attachment filter won't reject it

To bypass google's check, which is what you really want, simply remove the extensions from the file when you send it, and add them back after you download it. For example:

  • tar czvf file.tar.gz directory
  • mv file.tar.gz filetargz
  • [send filetargz via gmail]
  • [download filetargz]
  • [rename filetargz to file.tar.gz and open]

Inserting one list into another list in java?

100, it will hold the same references. Therefore if you make a change to a specific object in the list, it will affect the same object in anotherList.

Adding or removing objects in any of the list will not affect the other.

list and anotherList are two different instances, they only hold the same references of the objects "inside" them.

Building a fat jar using maven

You can use the maven-shade-plugin.

After configuring the shade plugin in your build the command mvn package will create one single jar with all dependencies merged into it.

Get the cartesian product of a series of lists?

Although there are many answers already, I would like to share some of my thoughts:

Iterative approach

def cartesian_iterative(pools):
  result = [[]]
  for pool in pools:
    result = [x+[y] for x in result for y in pool]
  return result

Recursive Approach

def cartesian_recursive(pools):
  if len(pools) > 2:
    pools[0] = product(pools[0], pools[1])
    del pools[1]
    return cartesian_recursive(pools)
  else:
    pools[0] = product(pools[0], pools[1])
    del pools[1]
    return pools
def product(x, y):
  return [xx + [yy] if isinstance(xx, list) else [xx] + [yy] for xx in x for yy in y]

Lambda Approach

def cartesian_reduct(pools):
  return reduce(lambda x,y: product(x,y) , pools)

For vs. while in C programming?

If you want a loop to execute while a condition is true, and not for a certain number of iterations, it is much easier for someone else to understand:

while (cond_true)

than something like this:

for (; cond_true ; )

SQL - How to select a row having a column with max value

SQL> create table t (mydate,value)
  2  as
  3  select to_date('18/5/2010, 1 pm','dd/mm/yyyy, hh am'), 40 from dual union all
  4  select to_date('18/5/2010, 2 pm','dd/mm/yyyy, hh am'), 20 from dual union all
  5  select to_date('18/5/2010, 3 pm','dd/mm/yyyy, hh am'), 60 from dual union all
  6  select to_date('18/5/2010, 4 pm','dd/mm/yyyy, hh am'), 30 from dual union all
  7  select to_date('18/5/2010, 5 pm','dd/mm/yyyy, hh am'), 60 from dual union all
  8  select to_date('18/5/2010, 6 pm','dd/mm/yyyy, hh am'), 25 from dual
  9  /

Table created.

SQL> select min(mydate) keep (dense_rank last order by value) mydate
  2       , max(value) value
  3    from t
  4  /

MYDATE                   VALUE
------------------- ----------
18-05-2010 15:00:00         60

1 row selected.

Regards, Rob.

Converting .NET DateTime to JSON

If you're having trouble getting to the time information, you can try something like this:

    d.date = d.date.replace('/Date(', '');
    d.date = d.date.replace(')/', '');  
    var expDate = new Date(parseInt(d.date));

How do I force Maven to use my local repository rather than going out to remote repos to retrieve artifacts?

Follow below steps:

    1. Ensure to delete all the contents of the jar folder located in your local except the jar that you want to keep.
      For example files like .repositories, .pom, .sha1, .lastUpdated etc.
    1. Execute mvn clean install -o command

This will help to use local repository jar files rather than connecting to any repository.

Difference between Eclipse Europa, Helios, Galileo

Those are just version designations (just like windows xp, vista or windows 7) which they are using to name their major releases, instead of using version numbers. so you'll want to use the newest eclipse version available, which is helios (or 3.6 which is the corresponding version number).

How to check is Apache2 is stopped in Ubuntu?

In the command line type service apache2 status then hit enter. The result should say:

Apache2 is running (pid xxxx)

Difference between MongoDB and Mongoose

If you are planning to use these components along with your proprietary code then please refer below information.

Mongodb:

  1. It's a database.
  2. This component is governed by the Affero General Public License (AGPL) license.
  3. If you link this component along with your proprietary code then you have to release your entire source code in the public domain, because of it's viral effect like (GPL, LGPL etc)
  4. If you are hosting your application over the cloud, the (2) will apply and also you have to release your installation information to the end users.

Mongoose:

  1. It's an object modeling tool.
  2. This component is governed by the MIT license.
  3. Allowed to use this component along with the proprietary code, without any restrictions.
  4. Shipping your application using any media or host is allowed.

How do I bind onchange event of a TextBox using JQuery?

Combination of keyup and change is not necessarily enough (browser's autocomplete and paste using mouse also changes the contents of a text box, but doesn't fire either of these events):

jquery change not working incase of dynamic value change

Difference between Iterator and Listiterator?

the following is that the difference between iterator and listIterator

iterator :

boolean hasNext();
E next();
void remove();

listIterator:

boolean hasNext();
E next();
boolean hasPrevious();
E previous();
int nextIndex();
int previousIndex();
void remove();
void set(E e);
void add(E e);

git diff between two different files

I believe using --no-index is what you're looking for:

git diff [<options>] --no-index [--] <path> <path>

as mentioned in the git manual:

This form is to compare the given two paths on the filesystem. You can omit the --no-index option when running the command in a working tree controlled by Git and at least one of the paths points outside the working tree, or when running the command outside a working tree controlled by Git.

Read a text file line by line in Qt

Use this code:

QFile inputFile(fileName);
if (inputFile.open(QIODevice::ReadOnly))
{
   QTextStream in(&inputFile);
   while (!in.atEnd())
   {
      QString line = in.readLine();
      ...
   }
   inputFile.close();
}

Convert to binary and keep leading zeros in Python

>>> '{:08b}'.format(1)
'00000001'

See: Format Specification Mini-Language


Note for Python 2.6 or older, you cannot omit the positional argument identifier before :, so use

>>> '{0:08b}'.format(1)
'00000001'      

How (and why) to use display: table-cell (CSS)

The display:table family of CSS properties is mostly there so that HTML tables can be defined in terms of them. Because they're so intimately linked to a specific tag structure, they don't see much use beyond that.

If you were going to use these properties in your page, you would need a tag structure that closely mimicked that of tables, even though you weren't actually using the <table> family of tags. A minimal version would be a single container element (display:table), with direct children that can all be represented as rows (display:table-row), which themselves have direct children that can all be represented as cells (display:table-cell). There are other properties that let you mimic other tags in the table family, but they require analogous structures in the HTML. Without this, it's going to be very hard (if not impossible) to make good use of these properties.

Fitting iframe inside a div

I think I may have a better solution for having a fully responsive iframe (a vimeo video in my case) embed on your site. Nest the iframe in a div. Give them the following styles:

div {
    width: 100%;
    height: 0;
    padding-bottom: 56%; /* Change this till it fits the dimensions of your video */
    position: relative;
}

div iframe {
    width: 100%;
    height: 100%;
    position: absolute;
    display: block;
    top: 0;
    left: 0;
}

Just did it now for a client, and it seems to be working: http://themilkrunsa.co.za/

Getting the Username from the HKEY_USERS values

The proper way to do this requires leveraging the SAM registry hive (on Windows 10, this requires NT AUTHORITY\SYSTEM privileges). The information you require is in the the key: HKEY_LOCAL_MACHINE\SAM\SAM\Domains\Account\Users\Names.

Each subkey is the username, and the default value in each subkey is a binary integer. This value (converted to decimal) actually corresponds to the last chunk of the of the SID.

Take "Administrator" for example, by default it is associated with the integer 0x1f4 (or 500).

So, in theory you could take the build a list of SIDS based on the subkey names of the HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\ProfileList key and/or HKEY_USERS key, parse out the the value after the last hyphen (-), and compare that to the info from the SAM hive.

If you don't have NT AUTHORITY\SYSTEM privileges, the next best way to approach this may be to follow the other method described in the answers here.

reference: https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-dtyp/81d92bba-d22b-4a8c-908a-554ab29148ab

I can not find my.cnf on my windows computer

Here is my answer:

  1. Win+R (shortcut for 'run'), type services.msc, Enter
  2. You should find an entry like 'MySQL56', right click on it, select properties
  3. You should see something like "D:/Program Files/MySQL/MySQL Server 5.6/bin\mysqld" --defaults-file="D:\ProgramData\MySQL\MySQL Server 5.6\my.ini" MySQL56

Full answer here: https://stackoverflow.com/a/20136523/1316649

selenium - chromedriver executable needs to be in PATH

You can download ChromeDriver here: https://sites.google.com/a/chromium.org/chromedriver/downloads

Then you have multiple options:

  • add it to your system path
  • put it in the same directory as your python script
  • specify the location directly via executable_path

    driver = webdriver.Chrome(executable_path='C:/path/to/chromedriver.exe')
    

Proper way to declare custom exceptions in modern Python?

A really simple approach:

class CustomError(Exception):
    pass

raise CustomError("Hmm, seems like this was custom coded...")

Or, have the error raise without printing __main__ (may look cleaner and neater):

class CustomError(Exception):
    __module__ = Exception.__module__

raise CustomError("Improved CustomError!")

Finding Key associated with max Value in a Java Map

Majority Element/ max element in the map :

public class Main {
     public static void main(String[] args) {
     int[] a = {1,3,4,3,4,3,2,3,3,3,3,3};
     List<Integer> list = Arrays.stream(a).boxed().collect(Collectors.toList());
     Map<Integer, Long> map = list.parallelStream()
             .collect(Collectors.groupingBy(Function.identity(),Collectors.counting()));
     System.out.println("Map => " + map);
     //{1=1, 2=1, 3=8, 4=2}
     map.entrySet()
     .stream()
     .max(Comparator.comparing(Entry::getValue))//compare the values and get the maximum value
     .map(Entry::getKey)// get the key appearing maximum number of times
     .ifPresentOrElse(System.out::println,() -> new RuntimeException("no such thing"));

     /*
      * OUTPUT : Map => {1=1, 2=1, 3=8, 4=2} 
      * 3
      */
     // or in  this way 
     System.out.println(".............");
     Integer maxAppearedElement = map.entrySet()
             .parallelStream()
             .max(Comparator.comparing(Entry::getValue))
             .map(Entry::getKey)
             .get();
     System.out.println(maxAppearedElement);

     } 
}

How to use a client certificate to authenticate and authorize in a Web API

Update:

Example from Microsoft:

https://docs.microsoft.com/en-us/azure/app-service/app-service-web-configure-tls-mutual-auth#special-considerations-for-certificate-validation

Original

This is how I got client certification working and checking that a specific Root CA had issued it as well as it being a specific certificate.

First I edited <src>\.vs\config\applicationhost.config and made this change: <section name="access" overrideModeDefault="Allow" />

This allows me to edit <system.webServer> in web.config and add the following lines which will require a client certification in IIS Express. Note: I edited this for development purposes, do not allow overrides in production.

For production follow a guide like this to set up the IIS:

https://medium.com/@hafizmohammedg/configuring-client-certificates-on-iis-95aef4174ddb

web.config:

<security>
  <access sslFlags="Ssl,SslNegotiateCert,SslRequireCert" />
</security>

API Controller:

[RequireSpecificCert]
public class ValuesController : ApiController
{
    // GET api/values
    public IHttpActionResult Get()
    {
        return Ok("It works!");
    }
}

Attribute:

public class RequireSpecificCertAttribute : AuthorizationFilterAttribute
{
    public override void OnAuthorization(HttpActionContext actionContext)
    {
        if (actionContext.Request.RequestUri.Scheme != Uri.UriSchemeHttps)
        {
            actionContext.Response = new HttpResponseMessage(System.Net.HttpStatusCode.Forbidden)
            {
                ReasonPhrase = "HTTPS Required"
            };
        }
        else
        {
            X509Certificate2 cert = actionContext.Request.GetClientCertificate();
            if (cert == null)
            {
                actionContext.Response = new HttpResponseMessage(System.Net.HttpStatusCode.Forbidden)
                {
                    ReasonPhrase = "Client Certificate Required"
                };

            }
            else
            {
                X509Chain chain = new X509Chain();

                //Needed because the error "The revocation function was unable to check revocation for the certificate" happened to me otherwise
                chain.ChainPolicy = new X509ChainPolicy()
                {
                    RevocationMode = X509RevocationMode.NoCheck,
                };
                try
                {
                    var chainBuilt = chain.Build(cert);
                    Debug.WriteLine(string.Format("Chain building status: {0}", chainBuilt));

                    var validCert = CheckCertificate(chain, cert);

                    if (chainBuilt == false || validCert == false)
                    {
                        actionContext.Response = new HttpResponseMessage(System.Net.HttpStatusCode.Forbidden)
                        {
                            ReasonPhrase = "Client Certificate not valid"
                        };
                        foreach (X509ChainStatus chainStatus in chain.ChainStatus)
                        {
                            Debug.WriteLine(string.Format("Chain error: {0} {1}", chainStatus.Status, chainStatus.StatusInformation));
                        }
                    }
                }
                catch (Exception ex)
                {
                    Debug.WriteLine(ex.ToString());
                }
            }

            base.OnAuthorization(actionContext);
        }
    }

    private bool CheckCertificate(X509Chain chain, X509Certificate2 cert)
    {
        var rootThumbprint = WebConfigurationManager.AppSettings["rootThumbprint"].ToUpper().Replace(" ", string.Empty);

        var clientThumbprint = WebConfigurationManager.AppSettings["clientThumbprint"].ToUpper().Replace(" ", string.Empty);

        //Check that the certificate have been issued by a specific Root Certificate
        var validRoot = chain.ChainElements.Cast<X509ChainElement>().Any(x => x.Certificate.Thumbprint.Equals(rootThumbprint, StringComparison.InvariantCultureIgnoreCase));

        //Check that the certificate thumbprint matches our expected thumbprint
        var validCert = cert.Thumbprint.Equals(clientThumbprint, StringComparison.InvariantCultureIgnoreCase);

        return validRoot && validCert;
    }
}

Can then call the API with client certification like this, tested from another web project.

[RoutePrefix("api/certificatetest")]
public class CertificateTestController : ApiController
{

    public IHttpActionResult Get()
    {
        var handler = new WebRequestHandler();
        handler.ClientCertificateOptions = ClientCertificateOption.Manual;
        handler.ClientCertificates.Add(GetClientCert());
        handler.UseProxy = false;
        var client = new HttpClient(handler);
        var result = client.GetAsync("https://localhost:44331/api/values").GetAwaiter().GetResult();
        var resultString = result.Content.ReadAsStringAsync().GetAwaiter().GetResult();
        return Ok(resultString);
    }

    private static X509Certificate GetClientCert()
    {
        X509Store store = null;
        try
        {
            store = new X509Store(StoreName.My, StoreLocation.CurrentUser);
            store.Open(OpenFlags.OpenExistingOnly | OpenFlags.ReadOnly);

            var certificateSerialNumber= "?81 c6 62 0a 73 c7 b1 aa 41 06 a3 ce 62 83 ae 25".ToUpper().Replace(" ", string.Empty);

            //Does not work for some reason, could be culture related
            //var certs = store.Certificates.Find(X509FindType.FindBySerialNumber, certificateSerialNumber, true);

            //if (certs.Count == 1)
            //{
            //    var cert = certs[0];
            //    return cert;
            //}

            var cert = store.Certificates.Cast<X509Certificate>().FirstOrDefault(x => x.GetSerialNumberString().Equals(certificateSerialNumber, StringComparison.InvariantCultureIgnoreCase));

            return cert;
        }
        finally
        {
            store?.Close();
        }
    }
}

Align nav-items to right side in bootstrap-4

With Bootstrap v4.0.0-alpha.6: Two <ul>s (.navbar-na), one with .mr-auto and one with .ml-auto:

<nav ...> 
  ...     
  <div class="collapse navbar-collapse">
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Left Link </a>
      </li>
    </ul>
    <ul class="navbar-nav ml-auto">
      <li class="nav-item">
        <a class="nav-link" href="#">Right Link </a>
      </li>
    </ul>
  </div>
</nav>

Explain __dict__ attribute

Basically it contains all the attributes which describe the object in question. It can be used to alter or read the attributes. Quoting from the documentation for __dict__

A dictionary or other mapping object used to store an object's (writable) attributes.

Remember, everything is an object in Python. When I say everything, I mean everything like functions, classes, objects etc (Ya you read it right, classes. Classes are also objects). For example:

def func():
    pass

func.temp = 1

print(func.__dict__)

class TempClass:
    a = 1
    def temp_function(self):
        pass

print(TempClass.__dict__)

will output

{'temp': 1}
{'__module__': '__main__', 
 'a': 1, 
 'temp_function': <function TempClass.temp_function at 0x10a3a2950>, 
 '__dict__': <attribute '__dict__' of 'TempClass' objects>, 
 '__weakref__': <attribute '__weakref__' of 'TempClass' objects>, 
 '__doc__': None}

How can I wrap or break long text/word in a fixed width span?

Try following css with addition of white-space:

span {
    display: block;
    word-wrap:break-word;
    width: 50px;
    white-space: normal
}

CSS Auto hide elements after 5 seconds

Why not try fadeOut?

_x000D_
_x000D_
$(document).ready(function() {_x000D_
  $('#plsme').fadeOut(5000); // 5 seconds x 1000 milisec = 5000 milisec_x000D_
});
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>_x000D_
<div id='plsme'>Loading... Please Wait</div>
_x000D_
_x000D_
_x000D_

fadeOut (Javascript Pure):

How to make fadeOut effect with pure JavaScript

How do I obtain a Query Execution Plan in SQL Server?

Query plans can be obtained from an Extended Events session via the query_post_execution_showplan event. Here's a sample XEvent session:

/*
    Generated via "Query Detail Tracking" template.
*/
CREATE EVENT SESSION [GetExecutionPlan] ON SERVER 
ADD EVENT sqlserver.query_post_execution_showplan(
    ACTION(package0.event_sequence,sqlserver.plan_handle,sqlserver.query_hash,sqlserver.query_plan_hash,sqlserver.session_id,sqlserver.sql_text,sqlserver.tsql_frame,sqlserver.tsql_stack)),

/* Remove any of the following events (or include additional events) as desired. */
ADD EVENT sqlserver.error_reported(
    ACTION(package0.event_sequence,sqlserver.client_app_name,sqlserver.database_id,sqlserver.plan_handle,sqlserver.query_hash,sqlserver.query_plan_hash,sqlserver.session_id,sqlserver.sql_text,sqlserver.tsql_frame,sqlserver.tsql_stack)
    WHERE ([package0].[greater_than_uint64]([sqlserver].[database_id],(4)) AND [package0].[equal_boolean]([sqlserver].[is_system],(0)))),
ADD EVENT sqlserver.module_end(SET collect_statement=(1)
    ACTION(package0.event_sequence,sqlserver.client_app_name,sqlserver.database_id,sqlserver.plan_handle,sqlserver.query_hash,sqlserver.query_plan_hash,sqlserver.session_id,sqlserver.sql_text,sqlserver.tsql_frame,sqlserver.tsql_stack)
    WHERE ([package0].[greater_than_uint64]([sqlserver].[database_id],(4)) AND [package0].[equal_boolean]([sqlserver].[is_system],(0)))),
ADD EVENT sqlserver.rpc_completed(
    ACTION(package0.event_sequence,sqlserver.client_app_name,sqlserver.database_id,sqlserver.plan_handle,sqlserver.query_hash,sqlserver.query_plan_hash,sqlserver.session_id,sqlserver.sql_text,sqlserver.tsql_frame,sqlserver.tsql_stack)
    WHERE ([package0].[greater_than_uint64]([sqlserver].[database_id],(4)) AND [package0].[equal_boolean]([sqlserver].[is_system],(0)))),
ADD EVENT sqlserver.sp_statement_completed(SET collect_object_name=(1)
    ACTION(package0.event_sequence,sqlserver.client_app_name,sqlserver.database_id,sqlserver.plan_handle,sqlserver.query_hash,sqlserver.query_plan_hash,sqlserver.session_id,sqlserver.sql_text,sqlserver.tsql_frame,sqlserver.tsql_stack)
    WHERE ([package0].[greater_than_uint64]([sqlserver].[database_id],(4)) AND [package0].[equal_boolean]([sqlserver].[is_system],(0)))),
ADD EVENT sqlserver.sql_batch_completed(
    ACTION(package0.event_sequence,sqlserver.client_app_name,sqlserver.database_id,sqlserver.plan_handle,sqlserver.query_hash,sqlserver.query_plan_hash,sqlserver.session_id,sqlserver.sql_text,sqlserver.tsql_frame,sqlserver.tsql_stack)
    WHERE ([package0].[greater_than_uint64]([sqlserver].[database_id],(4)) AND [package0].[equal_boolean]([sqlserver].[is_system],(0)))),
ADD EVENT sqlserver.sql_statement_completed(
    ACTION(package0.event_sequence,sqlserver.client_app_name,sqlserver.database_id,sqlserver.plan_handle,sqlserver.query_hash,sqlserver.query_plan_hash,sqlserver.session_id,sqlserver.sql_text,sqlserver.tsql_frame,sqlserver.tsql_stack)
    WHERE ([package0].[greater_than_uint64]([sqlserver].[database_id],(4)) AND [package0].[equal_boolean]([sqlserver].[is_system],(0)))) 
ADD TARGET package0.ring_buffer
WITH (MAX_MEMORY=4096 KB,EVENT_RETENTION_MODE=ALLOW_SINGLE_EVENT_LOSS,MAX_DISPATCH_LATENCY=30 SECONDS,MAX_EVENT_SIZE=0 KB,MEMORY_PARTITION_MODE=NONE,TRACK_CAUSALITY=ON,STARTUP_STATE=OFF)
GO

After you create the session, (in SSMS) go to the Object Explorer and delve down into Management | Extended Events | Sessions. Right-click the "GetExecutionPlan" session and start it. Right-click it again and select "Watch Live Data".

Next, open a new query window and run one or more queries. Here's one for AdventureWorks:

USE AdventureWorks;
GO

SELECT p.Name AS ProductName, 
    NonDiscountSales = (OrderQty * UnitPrice),
    Discounts = ((OrderQty * UnitPrice) * UnitPriceDiscount)
FROM Production.Product AS p 
INNER JOIN Sales.SalesOrderDetail AS sod
    ON p.ProductID = sod.ProductID 
ORDER BY ProductName DESC;
GO

After a moment or two, you should see some results in the "GetExecutionPlan: Live Data" tab. Click one of the query_post_execution_showplan events in the grid, and then click the "Query Plan" tab below the grid. It should look similar to this:

enter image description here

EDIT: The XEvent code and the screen shot were generated from SQL/SSMS 2012 w/ SP2. If you're using SQL 2008/R2, you might be able to tweak the script to make it run. But that version doesn't have a GUI, so you'd have to extract the showplan XML, save it as a *.sqlplan file and open it in SSMS. That's cumbersome. XEvents didn't exist in SQL 2005 or earlier. So, if you're not on SQL 2012 or later, I'd strongly suggest one of the other answers posted here.

How can I avoid running ActiveRecord callbacks?

For custom callbacks, use an attr_accessor and an unless in the callback.

Define your model as follows:

class Person << ActiveRecord::Base

  attr_accessor :skip_after_save_callbacks

  after_save :do_something, unless: :skip_after_save_callbacks

end

And then if you need to save the record without hitting the after_save callbacks you defined, set the skip_after_save_callbacks virtual attribute to true.

person.skip_after_save_callbacks #=> nil
person.save # By default, this *will* call `do_something` after saving.

person.skip_after_save_callbacks = true
person.save # This *will not* call `do_something` after saving.

person.skip_after_save_callbacks = nil # Always good to return this value back to its default so you don't accidentally skip callbacks.

HTML embed autoplay="false", but still plays automatically

The problem is your plugin. To solve this is to only enter this address:

chrome://flags/#enable-NPAPI

Click activate NPAPI, and finally restart at the bottom of the page.

Easiest way to split a string on newlines in .NET?

For a string variable s:

s.Split(new string[]{Environment.NewLine},StringSplitOptions.None)

This uses your environment's definition of line endings. On Windows, line endings are CR-LF (carriage return, line feed) or in C#'s escape characters \r\n.

This is a reliable solution, because if you recombine the lines with String.Join, this equals your original string:

var lines = s.Split(new string[]{Environment.NewLine},StringSplitOptions.None);
var reconstituted = String.Join(Environment.NewLine,lines);
Debug.Assert(s==reconstituted);

What not to do:

  • Use StringSplitOptions.RemoveEmptyEntries, because this will break markup such as Markdown where empty lines have syntactic purpose.
  • Split on separator new char[]{Environment.NewLine}, because on Windows this will create one empty string element for each new line.

Converting to upper and lower case in Java

WordUtils.capitalizeFully(str) from apache commons-lang has the exact semantics as required.

How to use KeyListener

Here is an SSCCE,

package experiment;

import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class KeyListenerTester extends JFrame implements KeyListener {

    JLabel label;

    public KeyListenerTester(String s) {
        super(s);
        JPanel p = new JPanel();
        label = new JLabel("Key Listener!");
        p.add(label);
        add(p);
        addKeyListener(this);
        setSize(200, 100);
        setVisible(true);

    }

    @Override
    public void keyTyped(KeyEvent e) {

        if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
            System.out.println("Right key typed");
        }
        if (e.getKeyCode() == KeyEvent.VK_LEFT) {
            System.out.println("Left key typed");
        }

    }

    @Override
    public void keyPressed(KeyEvent e) {

        if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
            System.out.println("Right key pressed");
        }
        if (e.getKeyCode() == KeyEvent.VK_LEFT) {
            System.out.println("Left key pressed");
        }

    }

    @Override
    public void keyReleased(KeyEvent e) {
        if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
            System.out.println("Right key Released");
        }
        if (e.getKeyCode() == KeyEvent.VK_LEFT) {
            System.out.println("Left key Released");
        }
    }

    public static void main(String[] args) {
        new KeyListenerTester("Key Listener Tester");
    }
}

Additionally read upon these links : How to Write a Key Listener and How to Use Key Bindings

how to get the base url in javascript

Should you want what is exactly specified in the web page, just use:

document.querySelector('head base')['href']

How to remove underline from a link in HTML?

I suggest to use :hover to avoid underline if mouse pointer is over an anchor

a:hover {
   text-decoration:none;
}

Finding an item in a List<> using C#

You have a few options:

  1. Using Enumerable.Where:

    list.Where(i => i.Property == value).FirstOrDefault();       // C# 3.0+
    
  2. Using List.Find:

    list.Find(i => i.Property == value);                         // C# 3.0+
    list.Find(delegate(Item i) { return i.Property == value; }); // C# 2.0+
    

Both of these options return default(T) (null for reference types) if no match is found.

As mentioned in the comments below, you should use the appropriate form of comparison for your scenario:

  • == for simple value types or where use of operator overloads are desired
  • object.Equals(a,b) for most scenarios where the type is unknown or comparison has potentially been overridden
  • string.Equals(a,b,StringComparison) for comparing strings
  • object.ReferenceEquals(a,b) for identity comparisons, which are usually the fastest

Android center view in FrameLayout doesn't work

I'd suggest a RelativeLayout instead of a FrameLayout.

Assuming that you want to have the TextView always below the ImageView I'd use following layout.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content">
    <ImageView
        android:id="@+id/imageview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerInParent="true"
        android:src="@drawable/icon"
        android:visibility="visible"/>
    <TextView
        android:id="@+id/textview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:layout_below="@id/imageview"
        android:gravity="center"
        android:text="@string/hello"/>
</RelativeLayout>

Note that if you set the visibility of an element to gone then the space that element would consume is gone whereas when you use invisible instead the space it'd consume will be preserved.

If you want to have the TextView on top of the ImageView then simply leave out the android:layout_alignParentTop or set it to false and on the TextView leave out the android:layout_below="@id/imageview" attribute. Like this.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content">
    <ImageView
        android:id="@+id/imageview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="false"
        android:layout_centerInParent="true"
        android:src="@drawable/icon"
        android:visibility="visible"/>
    <TextView
        android:id="@+id/textview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:gravity="center"
        android:text="@string/hello"/>
</RelativeLayout>

I hope this is what you were looking for.

How do you change the value inside of a textfield flutter?

TextEditingController()..text = "new text"

Error: Cannot Start Container: stat /bin/sh: no such file or directory"

This error

docker: Error response from daemon: OCI runtime create failed: container_linux.go:348: starting container process caused "exec: \"/bin/sh\": stat /bin/sh: no such file or directory": unknown.

occurs when creating a docker image from base image eg. scratch. This is because the resulting image does not have a shell to execute the image. If your use:

ENV EXECUTABLE hello
cmd [$EXECUTABLE]

in your docker file, docker uses /bin/sh to parse the input string. and hence the error. Inspecting on the image, your will find:

$docker inspect <image-name>
"Entrypoint": [
                "/bin/sh",
                "-c",
                "[$HM_APP]"
            ]

This means that the ENTRYPOINT or CMD arguments will be parsed using /bin/sh -c. The solution that worked for me is to parse the command as a JSON array of string e.g.

cmd ["hello"]

and inspecting the image again:

"Entrypoint": [
                "hello"
            ]

This removes the dependence on /bin/sh the docker app can now execute the binary file. Example:

FROM scratch

# Environmental variables

# Copy files
ADD . /
# Home dir
WORKDIR /bin

EXPOSE 8083
ENTRYPOINT ["hospitalms"]

Hope this helps someone in future.

How can I execute a python script from an html button?

It is discouraged and problematic yet doable. What you need is a custom URI scheme ie. You need to register and configure it on your machine and then hook an url with that scheme to the button.

URI scheme is the part before :// in an URI. Standard URI schemes are for example https or ftp or file. But there are custom like fx. mongodb. What you need is your own e.g. mypythonscript. It can be configured to exec the script or even just python with the script name in the params etc. It is of course a tradeoff between flexibility and security.

You can find more details in the links:

https://support.shotgunsoftware.com/hc/en-us/articles/219031308-Launching-applications-using-custom-browser-protocols

https://msdn.microsoft.com/en-us/library/aa767914(v=vs.85).aspx

EDIT: Added more details about what an custom scheme is.

SQL Server: converting UniqueIdentifier to string in a case statement

In my opinion, uniqueidentifier / GUID is neither a varchar nor an nvarchar but a char(36). Therefore I use:

CAST(xyz AS char(36))

jQuery Ajax PUT with parameters

Use:

$.ajax({
    url: 'feed/4', type: 'POST', data: "_METHOD=PUT&accessToken=63ce0fde", success: function(data) {
        console.log(data);
    }
});

Always remember to use _METHOD=PUT.

How to get the IP address of the docker host from inside a docker container

AFAIK, in the case of Docker for Linux (standard distribution), the IP address of the host will always be 172.17.0.1 (on the main network of docker, see comments to learn more).

The easiest way to get it is via ifconfig (interface docker0) from the host:

ifconfig

From inside a docker, the following command from a docker: ip -4 route show default | cut -d" " -f3

You can run it quickly in a docker with the following command line:

# 1. Run an ubuntu docker
# 2. Updates dependencies (quietly)
# 3. Install ip package   (quietly)
# 4. Shows (nicely) the ip of the host
# 5. Removes the docker (thanks to `--rm` arg)
docker run -it --rm ubuntu:20.10 bash -c "apt-get update > /dev/null && apt-get install iproute2 -y > /dev/null && ip -4 route show default | cut -d' ' -f3"

R color scatter plot points based on values

Here is a method using a lookup table of thresholds and associated colours to map the colours to the variable of interest.

 # make a grid 'Grd' of points and number points for side of square 'GrdD'
Grd <- expand.grid(seq(0.5,400.5,10),seq(0.5,400.5,10))
GrdD <- length(unique(Grd$Var1))

# Add z-values to the grid points
Grd$z <- rnorm(length(Grd$Var1), mean = 10, sd =2)

# Make a vector of thresholds 'Brks' to colour code z 
Brks <- c(seq(0,18,3),Inf)

# Make a vector of labels 'Lbls' for the colour threhsolds
Lbls <- Lbls <- c('0-3','3-6','6-9','9-12','12-15','15-18','>18')

# Make a vector of colours 'Clrs' for to match each range
Clrs <- c("grey50","dodgerblue","forestgreen","orange","red","purple","magenta")

# Make up lookup dataframe 'LkUp' of the lables and colours 
LkUp <- data.frame(cbind(Lbls,Clrs),stringsAsFactors = FALSE)

# Add a new variable 'Lbls' the grid dataframe mapping the labels based on z-value
Grd$Lbls <- as.character(cut(Grd$z, breaks = Brks, labels = Lbls))

# Add a new variable 'Clrs' to the grid dataframe based on the Lbls field in the grid and lookup table
Grd <- merge(Grd,LkUp, by.x = 'Lbls')

# Plot the grid using the 'Clrs' field for the colour of each point
plot(Grd$Var1,
     Grd$Var2,
     xlim = c(0,400),
     ylim = c(0,400),
     cex = 1.0,
     col = Grd$Clrs,
     pch = 20,
     xlab = 'mX',
     ylab = 'mY',
     main = 'My Grid',
     axes = FALSE,
     labels = FALSE,
     las = 1
)

axis(1,seq(0,400,100))
axis(2,seq(0,400,100),las = 1)
box(col = 'black')

legend("topleft", legend = Lbls, fill = Clrs, title = 'Z')

ASP.NET IIS Web.config [Internal Server Error]

Check this in the web.config and change overrideModeDefault from Deny to Allow.

<configSections>
  <sectionGroup name="system.webServer">
    <section name="handlers" overrideModeDefault="Deny" /> 
    <section name="modules" allowDefinition="MachineToApplication" overrideModeDefault="Deny" />

You can also manage sections on web server level in your IIS management console from "Feature Delegation".

Using Python String Formatting with Lists

x = ['1', '2', '3']
s = f"{x[0]} BLAH {x[1]} FOO {x[2]} BAR"
print(s)

The output is

1 BLAH 2 FOO 3 BAR

How to add MVC5 to Visual Studio 2013?

Visual Studio 2013 no longer has separate project types for different ASP.Net features.

You must select .NET Framework 4.5 (or higher) in order to see the ASP.NET Web Application template (For ASP.NET One).
So just select Visual C# > Web > ASP.NET Web Application, then select the MVC checkbox in the next step.

Note: Make sure not to select the C# > Web > Visual Studio 2012 sub folder.

Setting up Eclipse with JRE Path

I have several version of JDK (not JRE) instaled and I launch Eclipse with:

C:\eclipse\eclipse.exe -vm "%JAVA_HOME%\bin\javaw.exe" -data f:\dev\java\2013

As you can see, I set JAVA_HOME to point to the version of JDK I want to use.

I NEVER add javaw.exe in the PATH.

-data is used to choose a workspace for a particular job/client/context.

Convert double to float in Java

First of all, the fact that the value in the database is a float does not mean that it also fits in a Java float. Float is short for floating point, and floating point types of various precisions exist. Java types float and double are both floating point types of different precision. In a database both are called FLOAT. Since double has a higher precision than float, it probably is a better idea not to cast your value to a float, because you might lose precision.

You might also use BigDecimal, which represent an arbitrary-precision number.

How to add Google Maps Autocomplete search box?

// Bias the autocomplete object to the user's geographical location,
// as supplied by the browser's 'navigator.geolocation' object.
function geolocate() {
  if (navigator.geolocation) {
    navigator.geolocation.getCurrentPosition(function(poenter code heresition) {
      var geolocation = {
        lat: position.coords.latitude,
        lng: position.coords.longitude
      };
      var circle = new google.maps.Circle({
        center: geolocation,
        radius: position.coords.accuracy
      });
      autocomplete.setBounds(circle.getBounds());
    });
  }
}

Dropdown using javascript onchange

Something like this should do the trick

<select id="leave" onchange="leaveChange()">
  <option value="5">Get Married</option>
  <option value="100">Have a Baby</option>
  <option value="90">Adopt a Child</option>
  <option value="15">Retire</option>
  <option value="15">Military Leave</option>
  <option value="15">Medical Leave</option>
</select>

<div id="message"></div>

Javascript

function leaveChange() {
    if (document.getElementById("leave").value != "100"){
        document.getElementById("message").innerHTML = "Common message";
    }     
    else{
        document.getElementById("message").innerHTML = "Having a Baby!!";
    }        
}

jsFiddle Demo

A shorter version and more general could be

HTML

<select id="leave" onchange="leaveChange(this)">
  <option value="5">Get Married</option>
  <option value="100">Have a Baby</option>
  <option value="90">Adopt a Child</option>
  <option value="15">Retire</option>
  <option value="15">Military Leave</option>
  <option value="15">Medical Leave</option>
</select>

Javascript

function leaveChange(control) {
    var msg = control.value == "100" ? "Having a Baby!!" : "Common message";
    document.getElementById("message").innerHTML = msg;
}

<img>: Unsafe value used in a resource URL context

Pipe

// Angular
import { Pipe, PipeTransform } from '@angular/core';
import { DomSanitizer, SafeHtml, SafeStyle, SafeScript, SafeUrl, SafeResourceUrl } from '@angular/platform-browser';

/**
 * Sanitize HTML
 */
@Pipe({
  name: 'safe'
})
export class SafePipe implements PipeTransform {
  /**
   * Pipe Constructor
   *
   * @param _sanitizer: DomSanitezer
   */
  // tslint:disable-next-line
  constructor(protected _sanitizer: DomSanitizer) {
  }

  /**
   * Transform
   *
   * @param value: string
   * @param type: string
   */
  transform(value: string, type: string): SafeHtml | SafeStyle | SafeScript | SafeUrl | SafeResourceUrl {
    switch (type) {
      case 'html':
        return this._sanitizer.bypassSecurityTrustHtml(value);
      case 'style':
        return this._sanitizer.bypassSecurityTrustStyle(value);
      case 'script':
        return this._sanitizer.bypassSecurityTrustScript(value);
      case 'url':
        return this._sanitizer.bypassSecurityTrustUrl(value);
      case 'resourceUrl':
        return this._sanitizer.bypassSecurityTrustResourceUrl(value);
      default:
        return this._sanitizer.bypassSecurityTrustHtml(value);
    }
  }
}

Template

{{ data.url | safe:'url' }}

That's it!

Note: You shouldn't need it but here is the component use of the pipe
  // Public properties
  itsSafe: SafeHtml;

  // Private properties
  private safePipe: SafePipe = new SafePipe(this.domSanitizer);

  /**
   * Component constructor
   *
   * @param safePipe: SafeHtml
   * @param domSanitizer: DomSanitizer
   */
  constructor(private safePipe: SafePipe, private domSanitizer: DomSanitizer) {
  }

  /**
   * On init
   */
  ngOnInit(): void {
    this.itsSafe = this.safePipe.transform('<h1>Hi</h1>', 'html');
  }

How do you access the element HTML from within an Angular attribute directive?

I suggest using Render, as the ElementRef API doc suggests:

... take a look at Renderer which provides API that can safely be used even when direct access to native elements is not supported. Relying on direct DOM access creates tight coupling between your application and rendering layers which will make it impossible to separate the two and deploy your application into a web worker or Universal.

Always use the Renderer for it will make you code (or library you right) be able to work when using Universal or WebWorkers.

import { Directive, ElementRef, HostListener, Input, Renderer } from '@angular/core';

export class HighlightDirective {
    constructor(el: ElementRef, renderer: Renderer) {
        renderer.setElementProperty(el.nativeElement, 'innerHTML', 'some new value');
    }
}

It doesn't look like Render has a getElementProperty() method though, so I guess we still need to use NativeElement for that part. Or (better) pass the content in as an input property to the directive.

PANIC: Cannot find AVD system path. Please define ANDROID_SDK_ROOT (in windows 10)

I had the same problem when I was trying to move the android studio to another Drive as it was taking a lot of space in my C(Windows drive) Drive, Here's what fixed my problem:-

  1. Copy the C:\Users\ #YourUserName\ .android folder to another drive,
  2. Go to start environment variable make a new variable named ANDROID_SDK_HOME and add the path of the new location like mine is F:\Android AVD( don't add .android to it )
  3. Then add ANDROID_SDK_HOME to the existing Path variable.
  4. Open android studio, go to configure --> AVD manager and you'll see that you've successfully moved to a new location.

opening html from google drive

A lot of the solutions offered here do not seem to work anymore. I'm currently on a chromebook and wanted to view an HTML5 banner. This seems impossible now through Google Drive or other apps (as mentioned in previous comments).

The method I ended up using to view the HTML5 was the following:

  1. Open Google Adwords (create a free account if you dont have one)
  2. Click on Ads in the top panel
  3. Click on "+AD" and choose image ad
  4. Choose "upload an ad"
  5. Drag and drop your zip file into the area
  6. Click on Preview
  7. Voila, you will see your HTML5 banners in their full beauty

There may well an easier way, but this way is pretty good too. Hope it helps and worked well for me.

How do I get Maven to use the correct repositories?

the pom.xml for the project I have doesn't have this "http://repo1.maven.org/myurlhere" anywhere in it

All projects have http://repo1.maven.org/ declared as <repository> (and <pluginRepository>) by default. This repository, which is called the central repository, is inherited like others default settings from the "Super POM" (all projects inherit from the Super POM). So a POM is actually a combination of the Super POM, any parent POMs and the current POM. This combination is called the "effective POM" and can be printed using the effective-pom goal of the Maven Help plugin (useful for debugging).

And indeed, if you run:

mvn help:effective-pom

You'll see at least the following:

  <repositories>
    <repository>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
      <id>central</id>
      <name>Maven Repository Switchboard</name>
      <url>http://repo1.maven.org/maven2</url>
    </repository>
  </repositories>
  <pluginRepositories>
    <pluginRepository>
      <releases>
        <updatePolicy>never</updatePolicy>
      </releases>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
      <id>central</id>
      <name>Maven Plugin Repository</name>
      <url>http://repo1.maven.org/maven2</url>
    </pluginRepository>
  </pluginRepositories>

it has the absolute url where the maven repo is for the project but maven is still trying to download from the general maven repo

Maven will try to find dependencies in all repositories declared, including in the central one which is there by default as we saw. But, according to the trace you are showing, you only have one repository defined (the central repository) or maven would print something like this:

Reason: Unable to download the artifact from any repository

  url.project:project:pom:x.x

from the specified remote repositories:
  central (http://repo1.maven.org/),
  another-repository (http://another/repository)

So, basically, maven is unable to find the url.project:project:pom:x.x because it is not available in central.

But without knowing which project you've checked out (it has maybe specific instructions) or which dependency is missing (it can maybe be found in another repository), it's impossible to help you further.

How to force delete a file?

You have to close that application first. There is no way to delete it, if it's used by some application.

UnLock IT is a neat utility that helps you to take control of any file or folder when it is locked by some application or system. For every locked resource, you get a list of locking processes and can unlock it by terminating those processes. EMCO Unlock IT offers Windows Explorer integration that allows unlocking files and folders by one click in the context menu.

There's also Unlocker (not recommended, see Warning below), which is a free tool which helps locate any file locking handles running, and give you the option to turn it off. Then you can go ahead and do anything you want with those files.

Warning: The installer includes a lot of undesirable stuff. You're almost certainly better off with UnLock IT.

Form Validation With Bootstrap (jQuery)

I had your code setup on jsFiddle to try diagnose the problem.

http://jsfiddle.net/5WMff/

However, I don't seem to encounter your issue. Could you take a look and let us know?

HTML

<div class="hero-unit">
 <h1>Contact Form</h1> 
</br>
<form method="POST" action="contact-form-submission.php" class="form-horizontal" id="contact-form">
    <div class="control-group">
        <label class="control-label" for="name">Name</label>
        <div class="controls">
            <input type="text" name="name" id="name" placeholder="Your name">
        </div>
    </div>
    <div class="control-group">
        <label class="control-label" for="email">Email Address</label>
        <div class="controls">
            <input type="text" name="email" id="email" placeholder="Your email address">
        </div>
    </div>
    <div class="control-group">
        <label class="control-label" for="subject">Subject</label>
        <div class="controls">
            <select id="subject" name="subject">
                <option value="na" selected="">Choose One:</option>
                <option value="service">Feedback</option>
                <option value="suggestions">Suggestion</option>
                <option value="support">Question</option>
                <option value="other">Other</option>
            </select>
        </div>
    </div>
    <div class="control-group">
        <label class="control-label" for="message">Message</label>
        <div class="controls">
            <textarea name="message" id="message" rows="8" class="span5" placeholder="The message you want to send to us."></textarea>
        </div>
    </div>
    <div class="form-actions">
        <input type="hidden" name="save" value="contact">
        <button type="submit" class="btn btn-success">Submit Message</button>
        <button type="reset" class="btn">Cancel</button>
    </div>
</form>

Javascript

$(document).ready(function () {

$('#contact-form').validate({
    rules: {
        name: {
            minlength: 2,
            required: true
        },
        email: {
            required: true,
            email: true
        },
        message: {
            minlength: 2,
            required: true
        }
    },
    highlight: function (element) {
        $(element).closest('.control-group').removeClass('success').addClass('error');
    },
    success: function (element) {
        element.text('OK!').addClass('valid')
            .closest('.control-group').removeClass('error').addClass('success');
    }
});
});

Facebook database design?

TL;DR:

They use a stack architecture with cached graphs for everything above the MySQL bottom of their stack.

Long Answer:

I did some research on this myself because I was curious how they handle their huge amount of data and search it in a quick way. I've seen people complaining about custom made social network scripts becoming slow when the user base grows. After I did some benchmarking myself with just 10k users and 2.5 million friend connections - not even trying to bother about group permissions and likes and wall posts - it quickly turned out that this approach is flawed. So I've spent some time searching the web on how to do it better and came across this official Facebook article:

I really recommend you to watch the presentation of the first link above before continue reading. It's probably the best explanation of how FB works behind the scenes you can find.

The video and article tells you a few things:

  • They're using MySQL at the very bottom of their stack
  • Above the SQL DB there is the TAO layer which contains at least two levels of caching and is using graphs to describe the connections.
  • I could not find anything on what software / DB they actually use for their cached graphs

Let's take a look at this, friend connections are top left:

enter image description here

Well, this is a graph. :) It doesn't tell you how to build it in SQL, there are several ways to do it but this site has a good amount of different approaches. Attention: Consider that a relational DB is what it is: It's thought to store normalised data, not a graph structure. So it won't perform as good as a specialised graph database.

Also consider that you have to do more complex queries than just friends of friends, for example when you want to filter all locations around a given coordinate that you and your friends of friends like. A graph is the perfect solution here.

I can't tell you how to build it so that it will perform well but it clearly requires some trial and error and benchmarking.

Here is my disappointing test for just findings friends of friends:

DB Schema:

CREATE TABLE IF NOT EXISTS `friends` (
`id` int(11) NOT NULL,
  `user_id` int(11) NOT NULL,
  `friend_id` int(11) NOT NULL
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

Friends of Friends Query:

(
        select friend_id
        from friends
        where user_id = 1
    ) union (
        select distinct ff.friend_id
        from
            friends f
            join friends ff on ff.user_id = f.friend_id
        where f.user_id = 1
    )

I really recommend you to create you some sample data with at least 10k user records and each of them having at least 250 friend connections and then run this query. On my machine (i7 4770k, SSD, 16gb RAM) the result was ~0.18 seconds for that query. Maybe it can be optimized, I'm not a DB genius (suggestions are welcome). However, if this scales linear you're already at 1.8 seconds for just 100k users, 18 seconds for 1 million users.

This might still sound OKish for ~100k users but consider that you just fetched friends of friends and didn't do any more complex query like "display me only posts from friends of friends + do the permission check if I'm allowed or NOT allowed to see some of them + do a sub query to check if I liked any of them". You want to let the DB do the check on if you liked a post already or not or you'll have to do in code. Also consider that this is not the only query you run and that your have more than active user at the same time on a more or less popular site.

I think my answer answers the question how Facebook designed their friends relationship very well but I'm sorry that I can't tell you how to implement it in a way it will work fast. Implementing a social network is easy but making sure it performs well is clearly not - IMHO.

I've started experimenting with OrientDB to do the graph-queries and mapping my edges to the underlying SQL DB. If I ever get it done I'll write an article about it.

How to use if statements in underscore.js templates?

Depending on the situation and or your style, you might also wanna use print inside your <% %> tags, as it allows for direct output. Like:

<% if (typeof(id) != "undefined") {
     print(id);
}
else {
    print('new Model');
} %>

And for the original snippet with some concatenation:

<% if (typeof(date) != "undefined") {
    print('<span class="date">' + date + '</span>');
} %>

how to remove css property using javascript?

To change all classes for an element:

document.getElementById("ElementID").className = "CssClass";

To add an additional class to an element:

document.getElementById("ElementID").className += " CssClass";

To check if a class is already applied to an element:

if ( document.getElementById("ElementID").className.match(/(?:^|\s)CssClass(?!\S)/) )