#Firebird embedded | Programs & Examples on Firebird embedded

Try-catch speeding up my code?

One of the Roslyn engineers who specializes in understanding optimization of stack usage took a look at this and reports to me that there seems to be a problem in the interaction between the way the C# compiler generates local variable stores and the way the JIT compiler does register scheduling in the corresponding x86 code. The result is suboptimal code generation on the loads and stores of the locals.

For some reason unclear to all of us, the problematic code generation path is avoided when the JITter knows that the block is in a try-protected region.

This is pretty weird. We'll follow up with the JITter team and see whether we can get a bug entered so that they can fix this.

Also, we are working on improvements for Roslyn to the C# and VB compilers' algorithms for determining when locals can be made "ephemeral" -- that is, just pushed and popped on the stack, rather than allocated a specific location on the stack for the duration of the activation. We believe that the JITter will be able to do a better job of register allocation and whatnot if we give it better hints about when locals can be made "dead" earlier.

Thanks for bringing this to our attention, and apologies for the odd behaviour.

How to obtain a Thread id in Python?

Using the logging module you can automatically add the current thread identifier in each log entry. Just use one of these LogRecord mapping keys in your logger format string:

%(thread)d : Thread ID (if available).

%(threadName)s : Thread name (if available).

and set up your default handler with it:

logging.basicConfig(format="%(threadName)s:%(message)s")

View contents of database file in Android Studio

For Android Studio 3.X

View -> Tool Windows -> Device File Explorer
In The File Explorer data->data->com.(yourapplication package)->databases
Right Click On The Database And Save on your local machine. To open, the file you can use SQLite Studio by just dragging the Database file on it.

Here is the link to SQLite Studio : https://sqlitestudio.pl/index.rvt?act=download

jQuery click / toggle between two functions

modifying the first answer you are able to switch between n functions :

_x000D_

<!doctype html>_x000D_
<html lang="en">_x000D_
 <head>_x000D_
  <meta charset="UTF-8">_x000D_
  <meta name="Generator" content="EditPlus.com®">_x000D_
<!-- <script src="../js/jquery.js"></script> -->_x000D_
<script src="https://code.jquery.com/jquery-2.2.4.min.js"></script>_x000D_
  <title>my stupid example</title>_x000D_
_x000D_
 </head>_x000D_
 <body>_x000D_
 <nav>_x000D_
 <div>b<sub>1</sub></div>_x000D_
<div>b<sub>2</sub></div>_x000D_
<div>b<sub>3</sub></div>_x000D_
<!-- .......... -->_x000D_
<div>b<sub>n</sub></div>_x000D_
</nav>_x000D_
<script type="text/javascript">_x000D_
<!--_x000D_
$(document).ready(function() {_x000D_
 (function($) {_x000D_
        $.fn.clickToggle = function() {_x000D_
          var ta=arguments;_x000D_
         this.data('toggleclicked', 0);_x000D_
          this.click(function() {_x000D_
        id= $(this).index();console.log( id );_x000D_
            var data = $(this).data();_x000D_
            var tc = data.toggleclicked;_x000D_
            $.proxy(ta[id], this)();_x000D_
            data.toggleclicked = id_x000D_
          });_x000D_
          return this;_x000D_
        };_x000D_
   }(jQuery));_x000D_
_x000D_
    _x000D_
 $('nav div').clickToggle(_x000D_
     function() {alert('First handler');}, _x000D_
        function() {alert('Second handler');},_x000D_
        function() {alert('Third handler');}_x000D_
  //...........how manny parameters you want....._x000D_
  ,function() {alert('the `n handler');}_x000D_
 );_x000D_
_x000D_
});_x000D_
//-->_x000D_
</script>_x000D_
 </body>_x000D_
</html>

_x000D_

How to enable Ad Hoc Distributed Queries

sp_configure 'show advanced options', 1;
GO
RECONFIGURE;
GO
sp_configure 'Ad Hoc Distributed Queries', 1;
GO
RECONFIGURE;
GO

How to list all tags along with the full message in git?

Use --format option

git tag -l --format='%(tag) %(subject)'

How to position a table at the center of div horizontally & vertically

I discovered that I had to include

body { width:100%; }

for "margin: 0 auto" to work for tables.

How to set the default value for radio buttons in AngularJS?

why not just ng-checked="true"

what's the differences between r and rb in fopen

On most POSIX systems, it is ignored. But, check your system to be sure.

XNU

The mode string can also include the letter 'b' either as last character or as a character between the characters in any of the two-character strings described above. This is strictly for compatibility with ISO/IEC 9899:1990 ('ISO C90') and has no effect; the 'b' is ignored.

Linux

The mode string can also include the letter 'b' either as a last character or as a character between the characters in any of the two- character strings described above. This is strictly for compatibility with C89 and has no effect; the 'b' is ignored on all POSIX conforming systems, including Linux. (Other systems may treat text files and binary files differently, and adding the 'b' may be a good idea if you do I/O to a binary file and expect that your program may be ported to non-UNIX environments.)

Parse an URL in JavaScript

function parse_url(str, component) {
  //       discuss at: http://phpjs.org/functions/parse_url/
  //      original by: Steven Levithan (http://blog.stevenlevithan.com)
  // reimplemented by: Brett Zamir (http://brett-zamir.me)
  //         input by: Lorenzo Pisani
  //         input by: Tony
  //      improved by: Brett Zamir (http://brett-zamir.me)
  //             note: original by http://stevenlevithan.com/demo/parseuri/js/assets/parseuri.js
  //             note: blog post at http://blog.stevenlevithan.com/archives/parseuri
  //             note: demo at http://stevenlevithan.com/demo/parseuri/js/assets/parseuri.js
  //             note: Does not replace invalid characters with '_' as in PHP, nor does it return false with
  //             note: a seriously malformed URL.
  //             note: Besides function name, is essentially the same as parseUri as well as our allowing
  //             note: an extra slash after the scheme/protocol (to allow file:/// as in PHP)
  //        example 1: parse_url('http://username:password@hostname/path?arg=value#anchor');
  //        returns 1: {scheme: 'http', host: 'hostname', user: 'username', pass: 'password', path: '/path', query: 'arg=value', fragment: 'anchor'}

  var query, key = ['source', 'scheme', 'authority', 'userInfo', 'user', 'pass', 'host', 'port',
      'relative', 'path', 'directory', 'file', 'query', 'fragment'
    ],
    ini = (this.php_js && this.php_js.ini) || {},
    mode = (ini['phpjs.parse_url.mode'] &&
      ini['phpjs.parse_url.mode'].local_value) || 'php',
    parser = {
      php: /^(?:([^:\/?#]+):)?(?:\/\/()(?:(?:()(?:([^:@]*):?([^:@]*))?@)?([^:\/?#]*)(?::(\d*))?))?()(?:(()(?:(?:[^?#\/]*\/)*)()(?:[^?#]*))(?:\?([^#]*))?(?:#(.*))?)/,
      strict: /^(?:([^:\/?#]+):)?(?:\/\/((?:(([^:@]*):?([^:@]*))?@)?([^:\/?#]*)(?::(\d*))?))?((((?:[^?#\/]*\/)*)([^?#]*))(?:\?([^#]*))?(?:#(.*))?)/,
      loose: /^(?:(?![^:@]+:[^:@\/]*@)([^:\/?#.]+):)?(?:\/\/\/?)?((?:(([^:@]*):?([^:@]*))?@)?([^:\/?#]*)(?::(\d*))?)(((\/(?:[^?#](?![^?#\/]*\.[^?#\/.]+(?:[?#]|$)))*\/?)?([^?#\/]*))(?:\?([^#]*))?(?:#(.*))?)/ // Added one optional slash to post-scheme to catch file:/// (should restrict this)
    };

  var m = parser[mode].exec(str),
    uri = {},
    i = 14;
  while (i--) {
    if (m[i]) {
      uri[key[i]] = m[i];
    }
  }

  if (component) {
    return uri[component.replace('PHP_URL_', '')
      .toLowerCase()];
  }
  if (mode !== 'php') {
    var name = (ini['phpjs.parse_url.queryKey'] &&
      ini['phpjs.parse_url.queryKey'].local_value) || 'queryKey';
    parser = /(?:^|&)([^&=]*)=?([^&]*)/g;
    uri[name] = {};
    query = uri[key[12]] || '';
    query.replace(parser, function($0, $1, $2) {
      if ($1) {
        uri[name][$1] = $2;
      }
    });
  }
  delete uri.source;
  return uri;
}

reference

Maven build debug in Eclipse

if you are using Maven 2.0.8+, then it will be very simple, run mvndebug from the console, and connect to it via Remote Debug Java Application with port 8000.

Better way to find index of item in ArrayList?

Use indexOf() method to find first occurrence of the element in the collection.

Convert a PHP object to an associative array

You can quickly convert deeply nested objects to associative arrays by relying on the behavior of the JSON encode/decode functions:

$array = json_decode(json_encode($nested_object), true);

using nth-child in tables tr td

Current css version still doesn't support selector find by content. But there is a way, by using css selector find by attribute, but you have to put some identifier on all of the <td> that have $ inside. Example: using nth-child in tables tr td

html

<tr>
    <td>&nbsp;</td>
    <td data-rel='$'>$</td>
    <td>&nbsp;</td>
</tr>

css

table tr td[data-rel='$'] {
    background-color: #333;
    color: white;
}

Please try these example.

_x000D_

table tr td[data-content='$'] {_x000D_
    background-color: #333;_x000D_
    color: white;_x000D_
}

_x000D_

<table border="1">_x000D_
    <tr>_x000D_
        <td>A</td>_x000D_
        <td data-content='$'>$</td>_x000D_
        <td>B</td>_x000D_
        <td data-content='$'>$</td>_x000D_
        <td>C</td>_x000D_
        <td data-content='$'>$</td>_x000D_
        <td>D</td>_x000D_
    </tr>_x000D_
</table>

_x000D_

how to get yesterday's date in C#

var yesterday = DateTime.Now.AddDays(-1);

Setting Camera Parameters in OpenCV/Python

I wasn't able to fix the problem OpenCV either, but a video4linux (V4L2) workaround does work with OpenCV when using Linux. At least, it does on my Raspberry Pi with Rasbian and my cheap webcam. This is not as solid, light and portable as you'd like it to be, but for some situations it might be very useful nevertheless.

Make sure you have the v4l2-ctl application installed, e.g. from the Debian v4l-utils package. Than run (before running the python application, or from within) the command:

v4l2-ctl -d /dev/video1 -c exposure_auto=1 -c exposure_auto_priority=0 -c exposure_absolute=10

It overwrites your camera shutter time to manual settings and changes the shutter time (in ms?) with the last parameter to (in this example) 10. The lower this value, the darker the image.

How can I give eclipse more memory than 512M?

While working on an enterprise project in STS (heavily Eclipse based) I was crashing constantly and STS plateaued at around 1GB of RAM usage. I couldn't add new .war files to my local tomcat server and after deleting the tomcat folder to re-add it, found I couldn't re-add it either. Essentially almost anything that required a new popup besides the main menus was causing STS to freeze up.

I edited the STS.ini (your Eclipse.ini can be configured similarly) to:

--launcher.XXMaxPermSize 1024M -vmargs -Xms1536m -Xmx2048m -XX:MaxPermSize=1024m

Rebooted STS immediately and saw it plateau at about 1.5 gigs before finally not crashing

Show whitespace characters in Visual Studio Code

Show whitespace characters in Visual Studio Code

change the setting.json, by adding the following codes!

// Place your settings in this file to overwrite default and user settings.
{
    "editor.renderWhitespace": "all"
}

just like this!
(PS: there is no "true" option!, even it also works.)

UILabel is not auto-shrinking text to fit label size

In Swift 3 (Programmatically) I had to do this:

let lbl = UILabel()
lbl.numberOfLines = 0
lbl.lineBreakMode = .byClipping
lbl.adjustsFontSizeToFitWidth = true
lbl.minimumScaleFactor = 0.5
lbl.font = UIFont.systemFont(ofSize: 15)

nginx 502 bad gateway

I had the same problem while setting up an Ubuntu server. Turns out I was having the problem due to incorrect permissions on socket file.

If you are having the problem due to a permission problem, you can uncomment the following lines from: /etc/php5/fpm/pool.d/www.conf

listen.owner = www-data
listen.group = www-data
listen.mode = 0660

Alternatively, although I wouldn't recommend, you can give read and write permissions to all groups by using the following command.

sudo chmod go+rw /var/run/php5-fpm.sock

How do I efficiently iterate over each entry in a Java Map?

I like to concat a counter, then save the final value of the counter;

int counter = 0;
HashMap<String, String> m = new HashMap<String, String>();
for(int i = 0;i<items.length;i++)
{
m.put("firstname"+i, items.get(i).getFirstName());
counter = i;
}

m.put("recordCount",String.valueOf(counter));

Then when you want to retrieve:

int recordCount = Integer.parseInf(m.get("recordCount"));
for(int i =0 ;i<recordCount;i++)
{
System.out.println("First Name :" + m.get("firstname"+i));
}

How can I put an icon inside a TextInput in React Native?

Basically you can’t put an icon inside of a textInput but you can fake it by wrapping it inside a view and setting up some simple styling rules.

Here's how it works:

put both Icon and TextInput inside a parent View
set flexDirection of the parent to ‘row’ which will align the children next to each other
give TextInput flex 1 so it takes the full width of the parent View
give parent View a borderBottomWidth and push this border down with paddingBottom (this will make it appear like a regular textInput with a borderBottom)
- (or you can add any other style depending on how you want it to look)

Code:

<View style={styles.passwordContainer}>
  <TextInput
    style={styles.inputStyle}
      autoCorrect={false}
      secureTextEntry
      placeholder="Password"
      value={this.state.password}
      onChangeText={this.onPasswordEntry}
    />
  <Icon
    name='what_ever_icon_you_want'
    color='#000'
    size={14}
  />
</View>

Style:

passwordContainer: {
  flexDirection: 'row',
  borderBottomWidth: 1,
  borderColor: '#000',
  paddingBottom: 10,
},
inputStyle: {
  flex: 1,
},

(Note: the icon is underneath the TextInput so it appears on the far right, if it was above TextInput it would appear on the left.)

Programmatically shut down Spring Boot application

Closing a SpringApplication basically means closing the underlying ApplicationContext. The SpringApplication#run(String...) method gives you that ApplicationContext as a ConfigurableApplicationContext. You can then close() it yourself.

For example,

@SpringBootApplication
public class Example {
    public static void main(String[] args) {
        ConfigurableApplicationContext ctx = SpringApplication.run(Example.class, args);
        // ...determine it's time to shut down...
        ctx.close();
    }
}

Alternatively, you can use the static SpringApplication.exit(ApplicationContext, ExitCodeGenerator...) helper method to do it for you. For example,

@SpringBootApplication
public class Example {
    public static void main(String[] args) {
        ConfigurableApplicationContext ctx = SpringApplication.run(Example.class, args);
        // ...determine it's time to stop...
        int exitCode = SpringApplication.exit(ctx, new ExitCodeGenerator() {
            @Override
            public int getExitCode() {
                // no errors
                return 0;
            }
        });

        // or shortened to
        // int exitCode = SpringApplication.exit(ctx, () -> 0);

        System.exit(exitCode);
    }
}

Select first row in each GROUP BY group?

For SQl Server the most efficient way is:

with
ids as ( --condition for split table into groups
    select i from (values (9),(12),(17),(18),(19),(20),(22),(21),(23),(10)) as v(i) 
) 
,src as ( 
    select * from yourTable where  <condition> --use this as filter for other conditions
)
,joined as (
    select tops.* from ids 
    cross apply --it`s like for each rows
    (
        select top(1) * 
        from src
        where CommodityId = ids.i 
    ) as tops
)
select * from joined

and don't forget to create clustered index for used columns

How does the "view" method work in PyTorch?

`torch.Tensor.view()`

Simply put, torch.Tensor.view() which is inspired by numpy.ndarray.reshape() or numpy.reshape(), creates a new view of the tensor, as long as the new shape is compatible with the shape of the original tensor.

Let's understand this in detail using a concrete example.

In [43]: t = torch.arange(18) 

In [44]: t 
Out[44]: 
tensor([ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17])

With this tensor t of shape (18,), new views can only be created for the following shapes:

(1, 18) or equivalently (1, -1) or (-1, 18)
(2, 9) or equivalently (2, -1) or (-1, 9)
(3, 6) or equivalently (3, -1) or (-1, 6)
(6, 3) or equivalently (6, -1) or (-1, 3)
(9, 2) or equivalently (9, -1) or (-1, 2)
(18, 1) or equivalently (18, -1) or (-1, 1)

As we can already observe from the above shape tuples, the multiplication of the elements of the shape tuple (e.g. 2*9, 3*6 etc.) must always be equal to the total number of elements in the original tensor (18 in our example).

Another thing to observe is that we used a -1 in one of the places in each of the shape tuples. By using a -1, we are being lazy in doing the computation ourselves and rather delegate the task to PyTorch to do calculation of that value for the shape when it creates the new view. One important thing to note is that we can only use a single -1 in the shape tuple. The remaining values should be explicitly supplied by us. Else PyTorch will complain by throwing a RuntimeError:

RuntimeError: only one dimension can be inferred

So, with all of the above mentioned shapes, PyTorch will always return a new view of the original tensor t. This basically means that it just changes the stride information of the tensor for each of the new views that are requested.

Below are some examples illustrating how the strides of the tensors are changed with each new view.

# stride of our original tensor `t`
In [53]: t.stride() 
Out[53]: (1,)

Now, we will see the strides for the new views:

# shape (1, 18)
In [54]: t1 = t.view(1, -1)
# stride tensor `t1` with shape (1, 18)
In [55]: t1.stride() 
Out[55]: (18, 1)

# shape (2, 9)
In [56]: t2 = t.view(2, -1)
# stride of tensor `t2` with shape (2, 9)
In [57]: t2.stride()       
Out[57]: (9, 1)

# shape (3, 6)
In [59]: t3 = t.view(3, -1) 
# stride of tensor `t3` with shape (3, 6)
In [60]: t3.stride() 
Out[60]: (6, 1)

# shape (6, 3)
In [62]: t4 = t.view(6,-1)
# stride of tensor `t4` with shape (6, 3)
In [63]: t4.stride() 
Out[63]: (3, 1)

# shape (9, 2)
In [65]: t5 = t.view(9, -1) 
# stride of tensor `t5` with shape (9, 2)
In [66]: t5.stride()
Out[66]: (2, 1)

# shape (18, 1)
In [68]: t6 = t.view(18, -1)
# stride of tensor `t6` with shape (18, 1)
In [69]: t6.stride()
Out[69]: (1, 1)

So that's the magic of the view() function. It just changes the strides of the (original) tensor for each of the new views, as long as the shape of the new view is compatible with the original shape.

Another interesting thing one might observe from the strides tuples is that the value of the element in the 0^th position is equal to the value of the element in the 1^st position of the shape tuple.

In [74]: t3.shape 
Out[74]: torch.Size([3, 6])
                        |
In [75]: t3.stride()    |
Out[75]: (6, 1)         |
          |_____________|

This is because:

In [76]: t3 
Out[76]: 
tensor([[ 0,  1,  2,  3,  4,  5],
        [ 6,  7,  8,  9, 10, 11],
        [12, 13, 14, 15, 16, 17]])

the stride (6, 1) says that to go from one element to the next element along the 0^th dimension, we have to jump or take 6 steps. (i.e. to go from 0 to 6, one has to take 6 steps.) But to go from one element to the next element in the 1^st dimension, we just need only one step (for e.g. to go from 2 to 3).

Thus, the strides information is at the heart of how the elements are accessed from memory for performing the computation.

torch.reshape()

This function would return a view and is exactly the same as using torch.Tensor.view() as long as the new shape is compatible with the shape of the original tensor. Otherwise, it will return a copy.

However, the notes of torch.reshape() warns that:

contiguous inputs and inputs with compatible strides can be reshaped without copying, but one should not depend on the copying vs. viewing behavior.

fetch from origin with deleted remote branches?

If git fetch -p origin does not work for some reason (like because the origin repo no longer exists or you are unable to reach it), another solution is to remove the information which is stored locally on that branch by doing from the root of the repo:

rm .git/refs/remotes/origin/DELETED_BRANCH

or if it is stored in the file .git/packed-refs by deleting the corresponding line which is like

7a9930974b02a3b31cb2ebd17df6667514962685 refs/remotes/origin/DELETED_BRANCH

How to return a boolean method in java?

Best way would be to declare Boolean variable within the code block and return it at end of code, like this:

public boolean Test(){
    boolean booleanFlag= true; 
    if (A>B)
    {booleanFlag= true;}
    else 
    {booleanFlag = false;}
    return booleanFlag;

}

I find this the best way.

Source file not compiled Dev C++

I found a solution. Please follow the following steps:

Right Click the My comp. Icon
Click Advanced Setting.
CLick Environment Variable. On the top part of Environment Variable Click New
Set Variable name as: PATH then Set Variable Value as: (" the location of g++ .exe" ) For ex. C:\Program Files (x86)\Dev-Cpp\MinGW64\bin
Click OK

How to post ASP.NET MVC Ajax form using JavaScript rather than submit button

Simply place normal button indide Ajax.BeginForm and on click find parent form and normal submit. Ajax form in Razor:

@using (Ajax.BeginForm("AjaxPost", "Home", ajaxOptions))
    {        
        <div class="form-group">
            <div class="col-md-12">

                <button class="btn btn-primary" role="button" type="button" onclick="submitParentForm($(this))">Submit parent from Jquery</button>
            </div>
        </div>
    }

and Javascript:

function submitParentForm(sender) {
    var $formToSubmit = $(sender).closest('form');

    $formToSubmit.submit();
}

CSS background opacity with rgba not working in IE 8

This solution really works, try it. Tested in IE8

.dash-overlay{ 
   -ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr=#4C000000,endColorstr=#4C000000)"; 
}

How can I remove the search bar and footer added by the jQuery DataTables plugin?

For DataTables >=1.10, use:

$('table').dataTable({searching: false, paging: false, info: false});

For DataTables <1.10, use:

$('table').dataTable({bFilter: false, bInfo: false});

or using pure CSS:

.dataTables_filter, .dataTables_info { display: none; }

Margin-Top not working for span element?

Unlike div, p ¹ which are Block Level elements which can take up margin on all sides,span² cannot as it's an Inline element which takes up margins horizontally only.

From the specification:

Margin properties specify the width of the margin area of a box. The 'margin' shorthand property sets the margin for all four sides while the other margin properties only set their respective side. These properties apply to all elements, but vertical margins will not have any effect on non-replaced inline elements.

Demo 1 (Vertical margin not applied as span is an inline element)

Solution? Make your span element, display: inline-block; or display: block;.

Demo 2

Would suggest you to use display: inline-block; as it will be inline as well as block. Making it block only will result in your element to render on another line, as block level elements take 100% of horizontal space on the page, unless they are made inline-block or they are floated to left or right.

^{1. Block Level Elements - MDN Source}

^{2. Inline Elements - MDN Resource}

TortoiseSVN icons not showing up under Windows 7

A combination of solutions worked for me. I tried to kill and restart explorer.exe as suggested by @LeighRiffel. Did not work. I uninstalled dropbox because I rarely use it. Then, I tried the explorer thing again and it worked. Maybe you can reinstall dropbox after this and see if things are okay ? I don't care though.

Here are the steps: Run taskmgr.exe or task manager > processes tab > select explorer.exe > kill. Then click file option > new task > enter explorer.exe > ok.

How can I unstage my files again after making a local commit?

git reset --soft HEAD~1 should do what you want. After this, you'll have the first changes in the index (visible with git diff --cached), and your newest changes not staged. git status will then look like this:

# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#       modified:   foo.java
#
# Changes not staged for commit:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#       modified:   foo.java
#

You can then do git add foo.java and commit both changes at once.

Maven build Compilation error : Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project Maven

I had the same problem, the solution was set JAVA_HOME in environment variables.

mongodb count num of distinct values per field/key

With MongoDb 3.4.4 and newer, you can leverage the use of $arrayToObject operator and a $replaceRoot pipeline to get the counts.

For example, suppose you have a collection of users with different roles and you would like to calculate the distinct counts of the roles. You would need to run the following aggregate pipeline:

db.users.aggregate([
    { "$group": {
        "_id": { "$toLower": "$role" },
        "count": { "$sum": 1 }
    } },
    { "$group": {
        "_id": null,
        "counts": {
            "$push": { "k": "$_id", "v": "$count" }
        }
    } },
    { "$replaceRoot": {
        "newRoot": { "$arrayToObject": "$counts" }
    } }    
])

Example Output

{
    "user" : 67,
    "superuser" : 5,
    "admin" : 4,
    "moderator" : 12
}

geom_smooth() what are the methods available?

Sometimes it's asking the question that makes the answer jump out. The methods and extra arguments are listed on the ggplot2 wiki stat_smooth page.

Which is alluded to on the geom_smooth() page with:

"See stat_smooth for examples of using built in model fitting if you need some more flexible, this example shows you how to plot the fits from any model of your choosing".

It's not the first time I've seen arguments in examples for ggplot graphs that aren't specifically in the function. It does make it tough to work out the scope of each function, or maybe I am yet to stumble upon a magic explicit list that says what will and will not work within each function.

How do I concatenate a string with a variable?

It's just like you did. And I'll give you a small tip for these kind of silly things: just use the browser url box to try js syntax. for example, write this: javascript:alert("test"+5) and you have your answer. The problem in your code is probably that this element does not exist in your document... maybe it's inside a form or something. You can test this too by writing in the url: javascript:alert(document.horseThumb_5) to check where your mistake is.

How to change JDK version for an Eclipse project

Right click project -> Properties -> Java Build Path -> select JRE System Library click Edit and select JDK or JRE after then click Java Compiler and select Compiler compliance level to 1.8

How to deploy ASP.NET webservice to IIS 7?

rebuild project in VS
copy project folder to iis folder, probably C:\inetpub\wwwroot\
in iis manager (run>inetmgr) add website, point to folder, point application pool based on your .net
add web service to created website, almost the same as 3.
INSTALL ASP for windows 7 and .net 4.0: c:\windows\microsoft.net framework\v4.(some numbers)\regiis.exe -i
check access to web service on your browser

How can I reverse a list in Python?

With minimum amount of built-in functions, assuming it's interview settings

array = [1, 2, 3, 4, 5, 6,7, 8]
inverse = [] #create container for inverse array
length = len(array)  #to iterate later, returns 8 
counter = length - 1  #because the 8th element is on position 7 (as python starts from 0)

for i in range(length): 
   inverse.append(array[counter])
   counter -= 1
print(inverse)

connecting to mysql server on another PC in LAN

Follow a simple checklist:

Try pinging the machine ping 192.168.1.2
Ensure MySQL is running on the specified port 3306 i.e. it has not been modified.
Ensure that the other PC is not blocking inbound connections on that port. If it is, add a firewall exception to allow connections on port 3306 and allow inbound connections in general.
It would be nice if you could post the exact error as it is displayed when you attempt to make that connection.

Spark RDD to DataFrame python

Try if that works

sc = spark.sparkContext

# Infer the schema, and register the DataFrame as a table.
schemaPeople = spark.createDataFrame(RddName)
schemaPeople.createOrReplaceTempView("RddName")

AngularJS - Building a dynamic table based on a json

First off all I would like to thanks @MaximShoustin.

Thanks of you I have really nice table.

I provide some small modification in $scope.range and $scope.setPage.

In this way I have now possibility to go to the last page or come back to the first page. Also when I'm going to next or prev page the navigation is changing when $scope.gap is crossing. And the current page is not always on first position. For me it's looking more nicer.

Here is the new fiddle example: http://jsfiddle.net/qLBRZ/3/

CSS: fixed position on x-axis but not y?

This is an old thread but CSS3 has a solution.

position: sticky;

Have a look at this blog post.

Demonstration:

And this documentation.

Python Inverse of a Matrix

You could calculate the determinant of the matrix which is recursive and then form the adjoined matrix

Here is a short tutorial

I think this only works for square matrices

Another way of computing these involves gram-schmidt orthogonalization and then transposing the matrix, the transpose of an orthogonalized matrix is its inverse!

How to print out a variable in makefile

This makefile will generate the 'missing separator' error message:

all
    @echo NDK_PROJECT_PATH=$(NDK_PROJECT_PATH)

done:
        @echo "All done"

There's a tab before the @echo "All done" (though the done: rule and action are largely superfluous), but not before the @echo PATH=$(PATH).

The trouble is that the line starting all should either have a colon : or an equals = to indicate that it is a target line or a macro line, and it has neither, so the separator is missing.

The action that echoes the value of a variable must be associated with a target, possibly a dummy or PHONEY target. And that target line must have a colon on it. If you add a : after all in the example makefile and replace the leading blanks on the next line by a tab, it will work sanely.

You probably have an analogous problem near line 102 in the original makefile. If you showed 5 non-blank, non-comment lines before the echo operations that are failing, it would probably be possible to finish the diagnosis. However, since the question was asked in May 2013, it is unlikely that the broken makefile is still available now (August 2014), so this answer can't be validated formally. It can only be used to illustrate a plausible way in which the problem occurred.

Running powershell script within python script, how to make python print the powershell output while it is running

I don't have Python 2.7 installed, but in Python 3.3 calling Popen with stdout set to sys.stdout worked just fine. Not before I had escaped the backslashes in the path, though.

>>> import subprocess
>>> import sys
>>> p = subprocess.Popen(['powershell.exe', 'C:\\Temp\\test.ps1'], stdout=sys.stdout)
>>> Hello World
_

How to run an EXE file in PowerShell with parameters with spaces and quotes

An alternative answer is to use a Base64 encoded command switch:

powershell -EncodedCommand "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"

When decoded, you'll see it's the OP's original snippet with all arguments and double quotes preserved.

powershell.exe -EncodedCommand

Accepts a base-64-encoded string version of a command. Use this parameter
to submit commands to Windows PowerShell that require complex quotation
marks or curly braces.

The original command:

 C:\Program Files\IIS\Microsoft Web Deploy\msdeploy.exe -verb:sync -source:dbfullsql="Data Source=mysource;Integrated Security=false;User ID=sa;Pwd=sapass!;Database=mydb;" -dest:dbfullsql="Data Source=.\mydestsource;Integrated Security=false;User ID=sa;Pwd=sapass!;Database=mydb;",computername=10.10.10.10,username=administrator,password=adminpass"

It turns into this when encoded as Base64:

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

and here is how to replicate at home:

$command = 'C:\Program Files\IIS\Microsoft Web Deploy\msdeploy.exe -verb:sync -source:dbfullsql="Data Source=mysource;Integrated Security=false;User ID=sa;Pwd=sapass!;Database=mydb;" -dest:dbfullsql="Data Source=.\mydestsource;Integrated Security=false;User ID=sa;Pwd=sapass!;Database=mydb;",computername=10.10.10.10,username=administrator,password=adminpass"'
$bytes = [System.Text.Encoding]::Unicode.GetBytes($command)
$encodedCommand = [Convert]::ToBase64String($bytes)
$encodedCommand

#  The clip below copies the base64 string to your clipboard for right click and paste.
$encodedCommand | Clip

What is SaaS, PaaS and IaaS? With examples

When you are a simple client who wants to make use of a software but you have nothing in hand then you use SaaS.

When you have a software developed by you, but you want to deploy and run on a publicly available platform then you use PaaS.

When you have the software and the platform ready but you want the hardware to run then you use IaaS.

How do I Validate the File Type of a File Upload?

Well - you won't be able to do it server-side on post-back as the file will get submitted (uploaded) during the post-back.

I think you may be able to do it on the client using JavaScript. Personally, I use a third party component called radUpload by Telerik. It has a good client-side and server-side API, and it provides a progress bar for big file uploads.

I'm sure there are open source solutions available, too.

Using Postman to access OAuth 2.0 Google APIs

Postman will query Google API impersonating a Web Application

Generate an OAuth 2.0 token:

Ensure that the Google APIs are enabled
Create an OAuth 2.0 client ID
- Go to Google Console -> API -> OAuth consent screen
  - Add getpostman.com to the Authorized domains. Click Save.
- Go to Google Console -> API -> Credentials
  - Click 'Create credentials' -> OAuth client ID -> Web application
    - Name: 'getpostman'
    - Authorized redirect URIs: https://www.getpostman.com/oauth2/callback
- Copy the generated Client ID and Client secret fields for later use
In Postman select Authorization tab and select "OAuth 2.0" type. Click 'Get New Access Token'
- Fill the GET NEW ACCESS TOKEN form as following
  - Token Name: 'Google OAuth getpostman'
  - Grant Type: 'Authorization Code'
  - Callback URL: https://www.getpostman.com/oauth2/callback
  - Auth URL: https://accounts.google.com/o/oauth2/auth
  - Access Token URL: https://accounts.google.com/o/oauth2/token
  - Client ID: Client ID generated in the step 2 (e.g., '123456789012-abracadabra1234546789blablabla12.apps.googleusercontent.com')
  - Client Secret: Client secret generated in the step 2 (e.g., 'ABRACADABRAus1ZMGHvq9R-L')
  - Scope: see the Google docs for the required OAuth scope (e.g., https://www.googleapis.com/auth/cloud-platform)
  - State: Empty
  - Client Authentication: "Send as Basic Auth header"
- Click 'Request Token' and 'Use Token'
Set the method, parameters, and body of your request according to the Google docs

How to drop all stored procedures at once in SQL Server database?

Something like (Found at Delete All Procedures from a database using a Stored procedure in SQL Server).

Just so by the way, this seems like a VERY dangerous thing to do, just a thought...

declare @procName varchar(500)
declare cur cursor 

for select [name] from sys.objects where type = 'p'
open cur
fetch next from cur into @procName
while @@fetch_status = 0
begin
    exec('drop procedure [' + @procName + ']')
    fetch next from cur into @procName
end
close cur
deallocate cur

How to count lines of Java code using IntelliJ IDEA?

Statistic plugins works fine!

Here is a quick case:

Ctrl+Shift+A and serach for "Statistic" to open the panel.
You will see panel as the screenshot and then click Refresh for whole project or select your project or file and Refresh on selection for only selection.

Browser Caching of CSS files

That depends on what headers you are sending along with your CSS files. Check your server configuration as you are probably not sending them manually. Do a google search for "http caching" to learn about different caching options you can set. You can force the browser to download a fresh copy of the file everytime it loads it for instance, or you can cache the file for one week...

Array String Declaration

As Tr?n Si Long suggested, use

String[] mStrings = new String[title.length];

And replace string concatation with proper parenthesis.

mStrings[i] = (urlbase + (title[i].replaceAll("[^a-zA-Z]", ""))).toLowerCase() + imgSel;

Try this. If it's problem due to concatation, it will be resolved with proper brackets. Hope it helps.

Access to build environment variables from a groovy script in a Jenkins build step (Windows)

The only way I could get this to work (on Linux) was to follow this advice:

https://wiki.jenkins-ci.org/display/JENKINS/Parameterized+System+Groovy+script

import hudson.model.*

// get current thread / Executor and current build
def thr = Thread.currentThread()
def build = thr?.executable

// if you want the parameter by name ...
def hardcoded_param = "FOOBAR"
def resolver = build.buildVariableResolver
def hardcoded_param_value = resolver.resolve(hardcoded_param)

println "param ${hardcoded_param} value : ${hardcoded_param_value}"

This is on Jenkins 1.624 running on CentOS 6.7

Make: how to continue after a command fails?

Return successfully by blocking rm's returncode behind a pipe with the true command, which always returns 0 (success)

rm file | true

Android set bitmap to Imageview

    //decode base64 string to image
    imageBytes = Base64.decode(encodedImage, Base64.DEFAULT);
    Bitmap decodedImage = BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length);
    image.setImageBitmap(decodedImage);

  //setImageBitmap is imp

Passing route control with optional parameter after root in express?

That would work depending on what client.get does when passed undefined as its first parameter.

Something like this would be safer:

app.get('/:key?', function(req, res, next) {
    var key = req.params.key;
    if (!key) {
        next();
        return;
    }
    client.get(key, function(err, reply) {
        if(client.get(reply)) {
            res.redirect(reply);
        }
        else {
            res.render('index', {
                link: null
            });
        }
    });
});

There's no problem in calling next() inside the callback.

According to this, handlers are invoked in the order that they are added, so as long as your next route is app.get('/', ...) it will be called if there is no key.

How to use nanosleep() in C? What are `tim.tv_sec` and `tim.tv_nsec`?

Half a second is 500,000,000 nanoseconds, so your code should read:

tim.tv_sec  = 0;
tim.tv_nsec = 500000000L;

As things stand, you code is sleeping for 1.0000005s (1s + 500ns).

HTML5 iFrame Seamless Attribute

I thought this might be useful to someone:

in chrome version 32, a 2-pixels border automatically appears around iframes without the seamless attribute. It can be easily removed by adding this CSS rule:

iframe:not([seamless]) { border:none; }

Chrome uses the same selector with these default user-agent styles:

iframe:not([seamless]) {
  border: 2px inset;
  border-image-source: initial;
  border-image-slice: initial;
  border-image-width: initial;
  border-image-outset: initial;
  border-image-repeat: initial;
}

How to join two tables by multiple columns in SQL?

No, just include the different fields in the "ON" clause of 1 inner join statement:

SELECT * from Evalulation e JOIN Value v ON e.CaseNum = v.CaseNum
    AND e.FileNum = v.FileNum AND e.ActivityNum = v.ActivityNum

How do you grep a file and get the next 5 lines

You want:

grep -A 5 '19:55' file

From man grep:

Context Line Control

-A NUM, --after-context=NUM

Print NUM lines of trailing context after matching lines.  
Places a line containing a gup separator (described under --group-separator) 
between contiguous groups of matches.  With the -o or --only-matching
option, this has no effect and a warning is given.

-B NUM, --before-context=NUM

Print NUM lines of leading context before matching lines.  
Places a line containing a group separator (described under --group-separator) 
between contiguous groups of matches.  With the -o or --only-matching
option, this has no effect and a warning is given.

-C NUM, -NUM, --context=NUM

Print NUM lines of output context.  Places a line containing a group separator
(described under --group-separator) between contiguous groups of matches.  
With the -o or --only-matching option,  this  has  no effect and a warning
is given.

--group-separator=SEP

Use SEP as a group separator. By default SEP is double hyphen (--).

--no-group-separator

Use empty string as a group separator.

Trying to get PyCharm to work, keep getting "No Python interpreter selected"

This situation occurred to me when I uninstalled a method and tried to reinstall it. My very same interpreter, which worked before, suddenly stopped working. And this error occurred.

I tried restarting my PC, reinstalling Pycharm, invalidating caches, nothing worked.

Then I went here to reinstall the interpreter: https://www.python.org/downloads/

When you install it, there's an option to fix the python.exe interpreter. Click that. My IDE went back to normal working conditions.

Checking if output of a command contains a certain string in a shell script

A clean if/else conditional shell script:

if ./somecommand | grep -q 'some_string'; then
  echo "exists"
else
  echo "doesn't exist"
fi

AngularJS - Value attribute on an input text box is ignored when there is a ng-model used?

The Angular way

The correct Angular way to do this is to write a single page app, AJAX in the form template, then populate it dynamically from the model. The model is not populated from the form by default because the model is the single source of truth. Instead Angular will go the other way and try to populate the form from the model.

If however, you don't have time to start over from scratch

If you have an app written, this might involve some fairly hefty architectural changes. If you're trying to use Angular to enhance an existing form, rather than constructing an entire single page app from scratch, you can pull the value from the form and store it in the scope at link time using a directive. Angular will then bind the value in the scope back to the form and keep it in sync.

Using a directive

You can use a relatively simple directive to pull the value from the form and load it in to the current scope. Here I've defined an initFromForm directive.

var myApp = angular.module("myApp", ['initFromForm']);

angular.module('initFromForm', [])
  .directive("initFromForm", function ($parse) {
    return {
      link: function (scope, element, attrs) {
        var attr = attrs.initFromForm || attrs.ngModel || element.attrs('name'),
        val = attrs.value;
        if (attrs.type === "number") {val = parseInt(val)}
        $parse(attr).assign(scope, val);
      }
    };
  });

You can see I've defined a couple of fallbacks to get a model name. You can use this directive in conjunction with the ngModel directive, or bind to something other than $scope if you prefer.

Use it like this:

<input name="test" ng-model="toaster.test" value="hello" init-from-form />
{{toaster.test}}

Note this will also work with textareas, and select dropdowns.

<textarea name="test" ng-model="toaster.test" init-from-form>hello</textarea>
{{toaster.test}}

how to insert datetime into the SQL Database table?

DateTime values should be inserted as if they are strings surrounded by single quotes '20201231' but in many cases they need to be casted explicitly to datetime CAST(N'20201231' AS DATETIME) to avoid bad execution plans with CONVERSION_IMPLICIT warnings that affect negatively the performance. Hier is an example:

CREATE TABLE dbo.T(D DATETIME)

--wrong way
INSERT INTO dbo.T (D) VALUES ('20201231'), ('20201231')

--better way
INSERT INTO dbo.T (D) VALUES (CAST(N'20201231' AS DATETIME)), (CAST(N'20201231' AS DATETIME))

How do I parse a HTML page with Node.js

You can use the npm modules jsdom and htmlparser to create and parse a DOM in Node.JS.

Other options include:

BeautifulSoup for python
you can convert you html to xhtml and use XSLT
HTMLAgilityPack for .NET
CsQuery for .NET (my new favorite)
The spidermonkey and rhino JS engines have native E4X support. This may be useful, only if you convert your html to xhtml.

Out of all these options, I prefer using the Node.js option, because it uses the standard W3C DOM accessor methods and I can reuse code on both the client and server. I wish BeautifulSoup's methods were more similar to the W3C dom, and I think converting your HTML to XHTML to write XSLT is just plain sadistic.

How to extract a single value from JSON response?

using json.loads will turn your data into a python dictionary.

Dictionaries values are accessed using ['key']

resp_str = {
  "name" : "ns1:timeSeriesResponseType",
  "declaredType" : "org.cuahsi.waterml.TimeSeriesResponseType",
  "scope" : "javax.xml.bind.JAXBElement$GlobalScope",
  "value" : {
    "queryInfo" : {
      "creationTime" : 1349724919000,
      "queryURL" : "http://waterservices.usgs.gov/nwis/iv/",
      "criteria" : {
        "locationParam" : "[ALL:103232434]",
        "variableParam" : "[00060, 00065]"
      },
      "note" : [ {
        "value" : "[ALL:103232434]",
        "title" : "filter:sites"
      }, {
        "value" : "[mode=LATEST, modifiedSince=null]",
        "title" : "filter:timeRange"
      }, {
        "value" : "sdas01",
        "title" : "server"
      } ]
    }
  },
  "nil" : false,
  "globalScope" : true,
  "typeSubstituted" : false
}

would translate into a python diction

resp_dict = json.loads(resp_str)

resp_dict['name'] # "ns1:timeSeriesResponseType"

resp_dict['value']['queryInfo']['creationTime'] # 1349724919000

Remove all special characters from a string

This should do what you're looking for:

function clean($string) {
   $string = str_replace(' ', '-', $string); // Replaces all spaces with hyphens.

   return preg_replace('/[^A-Za-z0-9\-]/', '', $string); // Removes special chars.
}

Usage:

echo clean('a|"bc!@£de^&$f g');

Will output: abcdef-g

Edit:

Hey, just a quick question, how can I prevent multiple hyphens from being next to each other? and have them replaced with just 1?

function clean($string) {
   $string = str_replace(' ', '-', $string); // Replaces all spaces with hyphens.
   $string = preg_replace('/[^A-Za-z0-9\-]/', '', $string); // Removes special chars.

   return preg_replace('/-+/', '-', $string); // Replaces multiple hyphens with single one.
}

Convert Python program to C/C++ code?

http://code.google.com/p/py2c/ looks like a possibility - they also mention on their site: Cython, Shedskin and RPython and confirm that they are converting Python code to pure C/C++ which is much faster than C/C++ riddled with Python API calls. Note: I haven’t tried it but I am going to..

AngularJS - add HTML element to dom in directive without jQuery

You could use something like this

var el = document.createElement("svg");
el.style.width="600px";
el.style.height="100px";
....
iElement[0].appendChild(el)

Avoid Adding duplicate elements to a List C#

not a good way but kind of quick fix, take a bool to check if in whole list there is any duplicate entry.

bool containsKey;
string newKey;

public void addKey(string newKey)
{
    foreach (string key in MyKeys)
    {
        if (key == newKey)
        {
            containsKey = true;
        }
    }

    if (!containsKey)
    {
        MyKeys.add(newKey);
    }
    else
    {
        containsKey = false;
    }
}

Docker - Cannot remove dead container

I had the following error when removing a dead container (docker 17.06.1-ce on CentOS 7):

Error response from daemon: driver "overlay" failed to remove root filesystem for <some-id>: 
remove /var/lib/docker/overlay/<some-id>/merged: device or resource busy

Here is how I fixed it:

1. Check which other processes are also using docker resources

$ grep docker /proc/*/mountinfo

which outputs something like this, where the number after /proc/ is the pid:

/proc/10001/mountinfo:179...
/proc/10002/mountinfo:149...
/proc/12345/mountinfo:159 149 0:36 / /var/lib/docker/overlay/...

2. Check the process name of the above pid

$ ps -p 10001 -o comm=
dockerd
$ ps -p 10002 -o comm=
docker-containe
$ ps -p 12345 -o comm=
nginx   <<<-- This is suspicious!!!

So, nginx with pid 12345 seems to also be using /var/lib/docker/overlay/..., which is why we cannot remove the related container and get the device or resource busy error. (See here for a discussion on how nginx shares the same mount namespace with docker containers thus prevents its deletion.)

3. Stop nginx and then I can remove the container successfully.

$ sudo service nginx stop
$ docker rm <container-id>

Hibernate: best practice to pull all lazy collections

if you using jpa repository, set properties.put("hibernate.enable_lazy_load_no_trans",true); to jpaPropertymap

Regular Expression for password validation

Is a regular expression an easier/better way to enforce a simple constraint than the more obvious way?

static bool ValidatePassword( string password )
{
  const int MIN_LENGTH =  8 ;
  const int MAX_LENGTH = 15 ;

  if ( password == null ) throw new ArgumentNullException() ;

  bool meetsLengthRequirements = password.Length >= MIN_LENGTH && password.Length <= MAX_LENGTH ;
  bool hasUpperCaseLetter      = false ;
  bool hasLowerCaseLetter      = false ;
  bool hasDecimalDigit         = false ;

  if ( meetsLengthRequirements )
  {
    foreach (char c in password )
    {
      if      ( char.IsUpper(c) ) hasUpperCaseLetter = true ;
      else if ( char.IsLower(c) ) hasLowerCaseLetter = true ;
      else if ( char.IsDigit(c) ) hasDecimalDigit    = true ;
    }
  }

  bool isValid = meetsLengthRequirements
              && hasUpperCaseLetter
              && hasLowerCaseLetter
              && hasDecimalDigit
              ;
  return isValid ;

}

Which do you think that maintenance programmer 3 years from now who needs to modify the constraint will have an easier time understanding?

Get local IP address

This is the best code I found to get the current IP, avoiding get VMWare host or other invalid IP address.

public string GetLocalIpAddress()
{
    UnicastIPAddressInformation mostSuitableIp = null;

    var networkInterfaces = NetworkInterface.GetAllNetworkInterfaces();

    foreach (var network in networkInterfaces)
    {
        if (network.OperationalStatus != OperationalStatus.Up)
            continue;

        var properties = network.GetIPProperties();

        if (properties.GatewayAddresses.Count == 0)
            continue;

        foreach (var address in properties.UnicastAddresses)
        {
            if (address.Address.AddressFamily != AddressFamily.InterNetwork)
                continue;

            if (IPAddress.IsLoopback(address.Address))
                continue;

            if (!address.IsDnsEligible)
            {
                if (mostSuitableIp == null)
                    mostSuitableIp = address;
                continue;
            }

            // The best IP is the IP got from DHCP server
            if (address.PrefixOrigin != PrefixOrigin.Dhcp)
            {
                if (mostSuitableIp == null || !mostSuitableIp.IsDnsEligible)
                    mostSuitableIp = address;
                continue;
            }

            return address.Address.ToString();
        }
    }

    return mostSuitableIp != null 
        ? mostSuitableIp.Address.ToString()
        : "";
}

Using an array as needles in strpos

You can also try using strpbrk() for the negation (none of the letters have been found):

$find_letters = array('a', 'c', 'd');
$string = 'abcdefg';

if(strpbrk($string, implode($find_letters)) === false)
{
    echo 'None of these letters are found in the string!';
}

What is the purpose of willSet and didSet in Swift?

Getter and setter are sometimes too heavy to implement just to observe proper value changes. Usually this needs extra temporary variable handling and extra checks, and you will want to avoid even those tiny labour if you write hundreds of getters and setters. These stuffs are for the situation.

Undocumented NSURLErrorDomain error codes (-1001, -1003 and -1004) using StoreKit

see NSURLError.h Define

NSURLErrorUnknown =             -1,
NSURLErrorCancelled =           -999,
NSURLErrorBadURL =              -1000,
NSURLErrorTimedOut =            -1001,
NSURLErrorUnsupportedURL =          -1002,
NSURLErrorCannotFindHost =          -1003,
NSURLErrorCannotConnectToHost =         -1004,
NSURLErrorNetworkConnectionLost =       -1005,
NSURLErrorDNSLookupFailed =         -1006,
NSURLErrorHTTPTooManyRedirects =        -1007,
NSURLErrorResourceUnavailable =         -1008,
NSURLErrorNotConnectedToInternet =      -1009,
NSURLErrorRedirectToNonExistentLocation =   -1010,
NSURLErrorBadServerResponse =       -1011,
NSURLErrorUserCancelledAuthentication =     -1012,
NSURLErrorUserAuthenticationRequired =  -1013,
NSURLErrorZeroByteResource =        -1014,
NSURLErrorCannotDecodeRawData =             -1015,
NSURLErrorCannotDecodeContentData =         -1016,
NSURLErrorCannotParseResponse =             -1017,
NSURLErrorAppTransportSecurityRequiresSecureConnection NS_ENUM_AVAILABLE(10_11, 9_0) = -1022,
NSURLErrorFileDoesNotExist =        -1100,
NSURLErrorFileIsDirectory =         -1101,
NSURLErrorNoPermissionsToReadFile =     -1102,
NSURLErrorDataLengthExceedsMaximum NS_ENUM_AVAILABLE(10_5, 2_0) =   -1103,

// SSL errors
NSURLErrorSecureConnectionFailed =      -1200,
NSURLErrorServerCertificateHasBadDate =     -1201,
NSURLErrorServerCertificateUntrusted =  -1202,
NSURLErrorServerCertificateHasUnknownRoot = -1203,
NSURLErrorServerCertificateNotYetValid =    -1204,
NSURLErrorClientCertificateRejected =   -1205,
NSURLErrorClientCertificateRequired =   -1206,
NSURLErrorCannotLoadFromNetwork =       -2000,

// Download and file I/O errors
NSURLErrorCannotCreateFile =        -3000,
NSURLErrorCannotOpenFile =          -3001,
NSURLErrorCannotCloseFile =         -3002,
NSURLErrorCannotWriteToFile =       -3003,
NSURLErrorCannotRemoveFile =        -3004,
NSURLErrorCannotMoveFile =          -3005,
NSURLErrorDownloadDecodingFailedMidStream = -3006,
NSURLErrorDownloadDecodingFailedToComplete =-3007,

NSURLErrorInternationalRoamingOff NS_ENUM_AVAILABLE(10_7, 3_0) =         -1018,
NSURLErrorCallIsActive NS_ENUM_AVAILABLE(10_7, 3_0) =                    -1019,
NSURLErrorDataNotAllowed NS_ENUM_AVAILABLE(10_7, 3_0) =                  -1020,
NSURLErrorRequestBodyStreamExhausted NS_ENUM_AVAILABLE(10_7, 3_0) =      -1021,

NSURLErrorBackgroundSessionRequiresSharedContainer NS_ENUM_AVAILABLE(10_10, 8_0) = -995,
NSURLErrorBackgroundSessionInUseByAnotherProcess NS_ENUM_AVAILABLE(10_10, 8_0) = -996,
NSURLErrorBackgroundSessionWasDisconnected NS_ENUM_AVAILABLE(10_10, 8_0)= -997,

How To Auto-Format / Indent XML/HTML in Notepad++

Install Tidy2 plugin. I have Notepad++ v6.2.2, and Tidy2 works fine so far.

Get query from java.sql.PreparedStatement

I would assume it's possible to place a proxy between the DB and your app then observe the communication. I'm not familiar with what software you would use to do this.

SQL Query to add a new column after an existing column in SQL Server 2005

Microsoft SQL (AFAIK) does not allow you to alter the table and add a column after a specific column. Your best bet is using Sql Server Management Studio, or play around with either dropping and re-adding the table, or creating a new table and moving the data over manually. neither are very graceful.

MySQL does however:

ALTER TABLE mytable
ADD COLUMN  new_column <type>
AFTER       existing_column

What is the http-header "X-XSS-Protection"?

TL;DR: All well written web sites (/apps) must emit the header X-XSS-Protection: 0 and just forget about this feature. If you want to have extra security that better user agents can provide, use a strict Content-Security-Policy header.

Long answer:

HTTP header X-XSS-Protection is one of those things that Microsoft introduced in Internet Explorer 8.0 (MSIE 8) that was supposed to improve security of incorrectly written web sites.

The idea is to apply some kind of heuristics to try to detect reflection XSS attack and automatically neuter the attack.

The problematic part of this is "heuristics" and "neutering". The heuristics causes false positives and neutering cannot be safely done because it causes side-effects that can be used to implement XSS attacks and DoS attacks on perfectly safe web sites.

The bad part is that if a web site does not emit the header X-XSS-Protection then the browser will behave as if the header X-XSS-Protection: 1 had been emitted. The worst part is that this value is the least-safe value of all possible values for this header!

For a given secure web site (that is, the site does not have reflected XSS vulnerabilities) this "XSS protection" feature allows following attacks:

X-XSS-Protection: 1 allows attacker to selectively block parts of JavaScript and keep rest of the scripts running. This is possible because the heuristics of this feature are simply "if value of any GET parameter is found in the scripting part of the page source, the script will be automatically modified in user agent dependant way". In practice, the attacker can e.g. add parameter disablexss=<script src="framebuster.js" and the browser will automatically remove the string <script src="framebuster.js" from the actual page source. Note that the rest of the page continues run and the attacker just removed this part of page security. In practice, any JS in the page source can be modified. For some cases, a page without XSS vulnerability having reflected content can be used to run selected JavaScript on page due the neutering incorrectly turning plain text data into executable JavaScript code. (That is, turn textual data within a normal DOM text node into content of <script> tag and execute it!)

X-XSS-Protection: 1; mode=block allows attacker to leak data from the page source by using the behavior of the page as side-channel. For example, if the page contains JavaScript code along the lines of var csrf_secret="521231347843", the attacker simply adds an extra parameter e.g. leak=var%20csrf_secret="3 and if the page is NOT blocked, the 3 was incorrect first digit. The attacker tries again, this time leak=var%20csrf_secret="5 and the page loading will be aborted. This allows the attacker to know that the first digit of the secret is 5. The attacker then continues to guess the next digit. This allows easily brute-forcing of CSRF secrets or any other secret value in the <script> source.

In the end, if your site is full of XSS reflection attacks, using the default value of 1 will reduce the attack surface a little bit. However, if your site is secure and you don't emit X-XSS-Protection: 0, your site will be vulnerable with any browser that supports this feature. If you want defense in depth support from browsers against yet-unknown XSS vulnerabilities on your site, use a strict Content-Security-Policy header and keep sending 0 for this mis-feature. That doesn't open your site to any known vulnerabilities.

Currently this feature is enabled by default in MSIE, Safari and Google Chrome. This used to be enabled in Edge but Microsoft already removed this mis-feature from Edge. Mozilla Firefox never implemented this.

How to create a custom attribute in C#

The short answer is for creating an attribute in c# you only need to inherit it from Attribute class, Just this :)

But here I'm going to explain attributes in detail:

basically attributes are classes that we can use them for applying our logic to assemblies, classes, methods, properties, fields, ...

In .Net, Microsoft has provided some predefined Attributes like Obsolete or Validation Attributes like ( [Required], [StringLength(100)], [Range(0, 999.99)]), also we have kind of attributes like ActionFilters in asp.net that can be very useful for applying our desired logic to our codes (read this article about action filters if you are passionate to learn it)

one another point, you can apply a kind of configuration on your attribute via AttibuteUsage.

  [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, AllowMultiple = true)]

When you decorate an attribute class with AttributeUsage you can tell to c# compiler where I'm going to use this attribute: I'm going to use this on classes, on assemblies on properties or on ... and my attribute is allowed to use several times on defined targets(classes, assemblies, properties,...) or not?!

After this definition about attributes I'm going to show you an example: Imagine we want to define a new lesson in university and we want to allow just admins and masters in our university to define a new Lesson, Ok?

namespace ConsoleApp1
{
    /// <summary>
    /// All Roles in our scenario
    /// </summary>
    public enum UniversityRoles
    {
        Admin,
        Master,
        Employee,
        Student
    }

    /// <summary>
    /// This attribute will check the Max Length of Properties/fields
    /// </summary>
    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, AllowMultiple = true)]
    public class ValidRoleForAccess : Attribute
    {
        public ValidRoleForAccess(UniversityRoles role)
        {
            Role = role;
        }
        public UniversityRoles Role { get; private set; }

    }


    /// <summary>
    /// we suppose that just admins and masters can define new Lesson
    /// </summary>
    [ValidRoleForAccess(UniversityRoles.Admin)]
    [ValidRoleForAccess(UniversityRoles.Master)]
    public class Lesson
    {
        public Lesson(int id, string name, DateTime startTime, User owner)
        {
            var lessType = typeof(Lesson);
            var validRolesForAccesses = lessType.GetCustomAttributes<ValidRoleForAccess>();

            if (validRolesForAccesses.All(x => x.Role.ToString() != owner.GetType().Name))
            {
                throw new Exception("You are not Allowed to define a new lesson");
            }
            
            Id = id;
            Name = name;
            StartTime = startTime;
            Owner = owner;
        }
        public int Id { get; private set; }
        public string Name { get; private set; }
        public DateTime StartTime { get; private set; }

        /// <summary>
        /// Owner is some one who define the lesson in university website
        /// </summary>
        public User Owner { get; private set; }

    }

    public abstract class User
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public DateTime DateOfBirth { get; set; }
    }


    public class Master : User
    {
        public DateTime HireDate { get; set; }
        public Decimal Salary { get; set; }
        public string Department { get; set; }
    }

    public class Student : User
    {
        public float GPA { get; set; }
    }



    class Program
    {
        static void Main(string[] args)
        {

            #region  exampl1

            var master = new Master()
            {
                Name = "Hamid Hasani",
                Id = 1,
                DateOfBirth = new DateTime(1994, 8, 15),
                Department = "Computer Engineering",
                HireDate = new DateTime(2018, 1, 1),
                Salary = 10000
            };
            var math = new Lesson(1, "Math", DateTime.Today, master);

            #endregion

            #region exampl2
            var student = new Student()
            {
                Name = "Hamid Hasani",
                Id = 1,
                DateOfBirth = new DateTime(1994, 8, 15),
                GPA = 16
            };
            var literature = new Lesson(2, "literature", DateTime.Now.AddDays(7), student);
            #endregion

            ReadLine();
        }
    }


}

In the real world of programming maybe we don't use this approach for using attributes and I said this because of its educational point in using attributes

Importing from a relative path in Python

Funny enough, a same problem I just met, and I get this work in following way:

combining with linux command ln , we can make thing a lot simper:

1. cd Proj/Client
2. ln -s ../Common ./

3. cd Proj/Server
4. ln -s ../Common ./

And, now if you want to import some_stuff from file: Proj/Common/Common.py into your file: Proj/Client/Client.py, just like this:

# in Proj/Client/Client.py
from Common.Common import some_stuff

And, the same applies to Proj/Server, Also works for setup.py process, a same question discussed here, hope it helps !

How do I execute .js files locally in my browser?

If you're using Google Chrome you can use the Chrome Dev Editor: https://github.com/dart-lang/chromedeveditor

Use NSInteger as array index

According to the error message, you declared myLoc as a pointer to an NSInteger (NSInteger *myLoc) rather than an actual NSInteger (NSInteger myLoc). It needs to be the latter.

Fastest way to Remove Duplicate Value from a list<> by lambda

If you want to stick with the original List instead of creating a new one, you can something similar to what the Distinct() extension method does internally, i.e. use a HashSet to check for uniqueness:

HashSet<long> set = new HashSet<long>(longs.Count);
longs.RemoveAll(x => !set.Add(x));

The List class provides this convenient RemoveAll(predicate) method that drops all elements not satisfying the condition specified by the predicate. The predicate is a delegate taking a parameter of the list's element type and returning a bool value. The HashSet's Add() method returns true only if the set doesn't contain the item yet. Thus by removing any items from the list that can't be added to the set you effectively remove all duplicates.

How can I enable "URL Rewrite" Module in IIS 8.5 in Server 2012?

Worth mentioning: you should download the x64 version!

From the main download page (https://www.iis.net/downloads/microsoft/url-rewrite) click "additional downloads" (under the main download button) and download the x64 version (because for some reason - the default download version is x86)

Find child element in AngularJS directive

jQlite (angular's "jQuery" port) doesn't support lookup by classes.

One solution would be to include jQuery in your app.

Another is using QuerySelector or QuerySelectorAll:

link: function(scope, element, attrs) {
   console.log(element[0].querySelector('.list-scrollable'))
}

We use the first item in the element array, which is the HTML element. element.eq(0) would yield the same.

FIDDLE

Resolve conflicts using remote changes when pulling from Git remote

You can either use the answer from the duplicate link pointed by nvm.

Or you can resolve conflicts by using their changes (but some of your changes might be kept if they don't conflict with remote version):

git pull -s recursive -X theirs

How do I tell Spring Boot which main class to use for the executable jar?

Since Spring Boot 1.5, you can complete ignore the error-prone string literal in pom or build.gradle. The repackaging tool (via maven or gradle plugin) will pick the one annotated with @SpringBootApplication for you. (Refer to this issue for detail: https://github.com/spring-projects/spring-boot/issues/6496 )

java.time.format.DateTimeParseException: Text could not be parsed at index 21

The default parser can parse your input. So you don't need a custom formatter and

String dateTime = "2012-02-22T02:06:58.147Z";
ZonedDateTime d = ZonedDateTime.parse(dateTime);

works as expected.

What is the difference between a process and a thread?

They are almost as same... But the key difference is a thread is lightweight and a process is heavy-weight in terms of context switching, work load and so on.

View HTTP headers in Google Chrome?

For me, as of Google Chrome Version 46.0.2490.71 m, the Headers info area is a little hidden. To access:

While the browser is open, press F12 to access Web Developer tools
When opened, click the "Network" option
Initially, it is possible the page data is not present/up to date. Refresh the page if necessary
Observe the page information appears in the listing. (Also, make sure "All" is selected next to the "Hide data URLs" checkbox)

see screenshot

Java - sending HTTP parameters via POST method easily

I couldn't get Alan's example to actually do the post, so I ended up with this:

String urlParameters = "param1=a&param2=b&param3=c";
URL url = new URL("http://example.com/index.php");
URLConnection conn = url.openConnection();

conn.setDoOutput(true);

OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream());

writer.write(urlParameters);
writer.flush();

String line;
BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));

while ((line = reader.readLine()) != null) {
    System.out.println(line);
}
writer.close();
reader.close();

Rounded Corners Image in Flutter

With new version of flutter and material theme u need to use the "Padding" widgett too in order to have an image that doesn't fill its container.

For example if you want to insert a rounded image in the AppBar u must use padding or your image will always be as high as the AppBar.

Hope this will help someone

InkWell(
        onTap: () {
            print ('Click Profile Pic');
        },
        child: Padding(
            padding: const EdgeInsets.all(8.0),
            child: ClipOval(
                child: Image.asset(
                    'assets/images/profile1.jpg',
                ),
            ),
        ),
    ),

Clear MySQL query cache without restarting server

I believe you can use...

RESET QUERY CACHE;

...if the user you're running as has reload rights. Alternatively, you can defragment the query cache via...

FLUSH QUERY CACHE;

See the Query Cache Status and Maintenance section of the MySQL manual for more information.

If my interface must return Task what is the best way to have a no-operation implementation?

When you must return specified type:

Task.FromResult<MyClass>(null);

'dict' object has no attribute 'has_key'

Try:

if start not in graph:

For more info see ProgrammerSought

Better/Faster to Loop through set or list?

set is what you want, so you should use set. Trying to be clever introduces subtle bugs like forgetting to add one tomax(mylist)! Code defensively. Worry about what's faster when you determine that it is too slow.

range(min(mylist), max(mylist) + 1)  # <-- don't forget to add 1

How to make nginx to listen to server_name:port

The server_name^docs directive is used to identify virtual hosts, they're not used to set the binding.

netstat tells you that nginx listens on 0.0.0.0:80 which means that it will accept connections from any IP.

If you want to change the IP nginx binds on, you have to change the listen^docs rule.
So, if you want to set nginx to bind to localhost, you'd change that to:

listen 127.0.0.1:80;

In this way, requests that are not coming from localhost are discarded (they don't even hit nginx).

How to fix Error: listen EADDRINUSE while using nodejs?

EADDRINUSE translates to "The port you are trying to issue app.listen() on is being used by other programs". You can use a script like this to check if your port is in use and then change the port in your app.listen().

var net = require('net');
var errors = ['EADDRINUSE'];    
var isUsed = function(port) {
    var tester = net.createServer()
        .once('error', function (err) {
          if (!errors.includes(err.code)) {
           console.log("Port is in use, change the port.");
          }
        })
        .once('listening', function() {
            tester.once('close', function() { 
                console.log("You are good to go."); 
            })
            .close()
        })
        .listen(port);
}

You can add other errors in the errors array to check for all sorts of error types as well.

Wait until a process ends

I do the following in my application:

Process process = new Process();
process.StartInfo.FileName = executable;
process.StartInfo.Arguments = arguments;
process.StartInfo.ErrorDialog = true;
process.StartInfo.WindowStyle = ProcessWindowStyle.Minimized;
process.Start();
process.WaitForExit(1000 * 60 * 5);    // Wait up to five minutes.

There are a few extra features in there which you might find useful...

invalid command code ., despite escaping periods, using sed

Probably your new domain contain / ? If so, try using separator other than / in sed, e.g. #, , etc.

find ./ -type f -exec sed -i 's#192.168.20.1#new.domain.com#' {} \;

It would also be good to enclose s/// in single quote rather than double quote to avoid variable substitution or any other unexpected behaviour

How do I check/uncheck all checkboxes with a button using jQuery?

Check / Uncheck All with Intermediate property using jQuery

Get Checked Items in Array using getSelectedItems() method

Source Checkbox List Select / Unselect All with Indeterminate Master Check

HTML

<div class="container">
  <div class="card">
    <div class="card-header">
      <ul class="list-group list-group-flush">
        <li class="list-group-item">
          <input
            class="form-check-input"
            type="checkbox"
            value="selectAll"
            id="masterCheck"
          />
          <label class="form-check-label" for="masterCheck">
            Select / Unselect All
          </label>
        </li>
      </ul>
    </div>
    <div class="card-body">
      <ul class="list-group list-group-flush" id="list-wrapper">
        <li class="list-group-item">
          <input
            class="form-check-input"
            type="checkbox"
            value="item1"
            id="item1"
          />
          <label class="form-check-label" for="item1">
            Item 1
          </label>
        </li>
        <li class="list-group-item">
          <input
            class="form-check-input"
            type="checkbox"
            value="item2"
            id="item2"
          />
          <label class="form-check-label" for="item2">
            Item 2
          </label>
        </li>
        <li class="list-group-item">
          <input
            class="form-check-input"
            type="checkbox"
            value="item3"
            id="item3"
          />
          <label class="form-check-label" for="item3">
            Item 3
          </label>
        </li>
        <li class="list-group-item">
          <input
            class="form-check-input"
            type="checkbox"
            value="item4"
            id="item4"
          />
          <label class="form-check-label" for="item4">
            Item 4
          </label>
        </li>
        <li class="list-group-item">
          <input
            class="form-check-input"
            type="checkbox"
            value="item5"
            id="item5"
          />
          <label class="form-check-label" for="item5">
            Item 5
          </label>
        </li>
        <li class="list-group-item" id="selected-values"></li>
      </ul>
    </div>
  </div>
</div>

jQuery

  $(function() {
    // ID selector on Master Checkbox
    var masterCheck = $("#masterCheck");
    // ID selector on Items Container
    var listCheckItems = $("#list-wrapper :checkbox");

    // Click Event on Master Check
    masterCheck.on("click", function() {
      var isMasterChecked = $(this).is(":checked");
      listCheckItems.prop("checked", isMasterChecked);
      getSelectedItems();
    });

    // Change Event on each item checkbox
    listCheckItems.on("change", function() {
      // Total Checkboxes in list
      var totalItems = listCheckItems.length;
      // Total Checked Checkboxes in list
      var checkedItems = listCheckItems.filter(":checked").length;

      //If all are checked
      if (totalItems == checkedItems) {
        masterCheck.prop("indeterminate", false);
        masterCheck.prop("checked", true);
      }
      // Not all but only some are checked
      else if (checkedItems > 0 && checkedItems < totalItems) {
        masterCheck.prop("indeterminate", true);
      }
      //If none is checked
      else {
        masterCheck.prop("indeterminate", false);
        masterCheck.prop("checked", false);
      }
      getSelectedItems();
    });

    function getSelectedItems() {
      var getCheckedValues = [];
      getCheckedValues = [];
      listCheckItems.filter(":checked").each(function() {
        getCheckedValues.push($(this).val());
      });
      $("#selected-values").html(JSON.stringify(getCheckedValues));
    }
  });

SQL: ... WHERE X IN (SELECT Y FROM ...)

One reason why you might prefer to use a JOIN rather than NOT IN is that if the Values in the NOT IN clause contain any NULLs you will always get back no results. If you do use NOT IN remember to always consider whether the sub query might bring back a NULL value!

RE: Question in Comments

'x' NOT IN (NULL,'a','b')

= 'x' <> NULL and 'x' <> 'a' and 'x' <> 'b'

= Unknown and True and True

= Unknown

Import error No module named skimage

Hey this is pretty simple to solve this error.Just follow this steps:

First uninstall any existing installation:

pip uninstall scikit-image

or, on conda-based systems:

conda uninstall scikit-image

Now, clone scikit-image on your local computer, and install:

git clone https://github.com/scikit-image/scikit-image.git
cd scikit-image
pip install -e .

To update the installation:

git pull  # Grab latest source
pip install -e .  # Reinstall

For other os and manual process please check this Link.

What are the differences between a program and an application?

When I studied IT in college my prof. made it simple for me:

"A computer "program" and an "application" (a.k.a. 'app') are one-in-the-same. The only difference is a technical one. While both are the same, an 'application' is a computer program launched and dependent upon an operating system to execute."

Got it right on the exam.

So when you click on a word processor, for example, it is an application, as is that hidden file that runs the printer spooler launched only by the OS. The two programs depend on the OS, whereby the OS itself or your internal BIOS programming are not 'apps' in the technical sense as they communicate directly with the computer hardware itself.

Unless the definition has changed in the past few years, commercial entities like Microsoft and Apple are not using the terms properly, preferring sexy marketing by making the term 'apps' seem like something popular market and 'new', because a "computer program" sounds too 'nerdy'. :(

How to remove all ListBox items?

Write the following code in the .cs file:

ListBox.Items.Clear();

$ is not a function - jQuery error

That error kicks in when you have forgot to include the jQuery library in your page or there is conflict between libraries - for example you be using any other javascript library on your page.

Take a look at this for more info:

Using jQuery with other libraries

Laravel-5 'LIKE' equivalent (Eloquent)

I think this is better, following the good practices of passing parameters to the query:

BookingDates::whereRaw('email = ? or name like ?', [$request->email,"%{$request->name}%"])->get();

You can see it in the documentation, Laravel 5.5.

You can also use the Laravel scout and make it easier with search. Here is the documentation.

How to create a table from select query result in SQL Server 2008

Use following syntax to create new table from old table in SQL server 2008

Select * into new_table  from  old_table

error LNK2005: xxx already defined in MSVCRT.lib(MSVCR100.dll) C:\something\LIBCMT.lib(setlocal.obj)

You are mixing code that was compiled with /MD (use DLL version of CRT) with code that was compiled with /MT (use static CRT library). That cannot work, all source code files must be compiled with the same setting. Given that you use libraries that were pre-compiled with /MD, almost always the correct setting, you must compile your own code with this setting as well.

Project + Properties, C/C++, Code Generation, Runtime Library.

Beware that these libraries were probably compiled with an earlier version of the CRT, msvcr100.dll is quite new. Not sure if that will cause trouble, you may have to prevent the linker from generating a manifest. You must also make sure to deploy the DLLs you need to the target machine, including msvcr100.dll

What exceptions should be thrown for invalid or unexpected parameters in .NET?

ArgumentException:

ArgumentException is thrown when a method is invoked and at least one of the passed arguments does not meet the parameter specification of the called method. All instances of ArgumentException should carry a meaningful error message describing the invalid argument, as well as the expected range of values for the argument.

A few subclasses also exist for specific types of invalidity. The link has summaries of the subtypes and when they should apply.

How to Execute a Python File in Notepad ++?

I started using Notepad++ for Python very recently and I found this method very easy. Once you are ready to run the code,right-click on the tab of your code in Notepad++ window and select "Open Containing Folder in cmd". This will open the Command Prompt into the folder where the current program is stored. All you need to do now is to execute:

python

This was done on Notepad++ (Build 10 Jan 2015).

I can't add the screenshots, so here's a blog post with the screenshots - http://coder-decoder.blogspot.in/2015/03/using-notepad-in-windows-to-edit-and.html

How do I get list of methods in a Python class?

An example (listing the methods of the optparse.OptionParser class):

>>> from optparse import OptionParser
>>> import inspect
#python2
>>> inspect.getmembers(OptionParser, predicate=inspect.ismethod)
[([('__init__', <unbound method OptionParser.__init__>),
...
 ('add_option', <unbound method OptionParser.add_option>),
 ('add_option_group', <unbound method OptionParser.add_option_group>),
 ('add_options', <unbound method OptionParser.add_options>),
 ('check_values', <unbound method OptionParser.check_values>),
 ('destroy', <unbound method OptionParser.destroy>),
 ('disable_interspersed_args',
  <unbound method OptionParser.disable_interspersed_args>),
 ('enable_interspersed_args',
  <unbound method OptionParser.enable_interspersed_args>),
 ('error', <unbound method OptionParser.error>),
 ('exit', <unbound method OptionParser.exit>),
 ('expand_prog_name', <unbound method OptionParser.expand_prog_name>),
 ...
 ]
# python3
>>> inspect.getmembers(OptionParser, predicate=inspect.isfunction)
...

Notice that getmembers returns a list of 2-tuples. The first item is the name of the member, the second item is the value.

You can also pass an instance to getmembers:

>>> parser = OptionParser()
>>> inspect.getmembers(parser, predicate=inspect.ismethod)
...

Where does gcc look for C and C++ header files?

The CPP Section of the GCC Manual indicates that header files may be located in the following directories:

GCC looks in several different places for headers. On a normal Unix system, if you do not instruct it otherwise, it will look for headers requested with #include in:

 /usr/local/include
 libdir/gcc/target/version/include
 /usr/target/include
 /usr/include

For C++ programs, it will also look in /usr/include/g++-v3, first.

How can I make a list of installed packages in a certain virtualenv?

You can list only packages in the virtualenv by pip freeze --local or pip list --local. This option works irrespective of whether you have global site packages visible in the virtualenv.

Note that restricting the virtualenv to not use global site packages isn't the answer to the problem, because the question is on how to separate the two lists, not how to constrain our workflow to fit limitations of tools.

Credits to @gvalkov's comment here. Cf. also this issue.

Can't use SURF, SIFT in OpenCV

There is a pip source that makes this very easy.

If you have another version of opencv-python installed use this command to remove it to avoid conflicts:
```
pip uninstall opencv-python
```
Then install the contrib version with this:
```
pip install opencv-contrib-python
```

SIFT usage:

import cv2
sift = cv2.xfeatures2d.SIFT_create()

Reverse a string in Python

Here is simply:

print "loremipsum"[-1::-1]

and some logically:

def str_reverse_fun():
    empty_list = []
    new_str = 'loremipsum'
    index = len(new_str)
    while index:
        index = index - 1
        empty_list.append(new_str[index])
    return ''.join(empty_list)
print str_reverse_fun()

output:

muspimerol

How to compute precision, recall, accuracy and f1-score for the multiclass case with scikit learn?

I think there is a lot of confusion about which weights are used for what. I am not sure I know precisely what bothers you so I am going to cover different topics, bear with me ;).

Class weights

The weights from the class_weight parameter are used to train the classifier. They are not used in the calculation of any of the metrics you are using: with different class weights, the numbers will be different simply because the classifier is different.

Basically in every scikit-learn classifier, the class weights are used to tell your model how important a class is. That means that during the training, the classifier will make extra efforts to classify properly the classes with high weights.
How they do that is algorithm-specific. If you want details about how it works for SVC and the doc does not make sense to you, feel free to mention it.

The metrics

Once you have a classifier, you want to know how well it is performing. Here you can use the metrics you mentioned: accuracy, recall_score, f1_score...

Usually when the class distribution is unbalanced, accuracy is considered a poor choice as it gives high scores to models which just predict the most frequent class.

I will not detail all these metrics but note that, with the exception of accuracy, they are naturally applied at the class level: as you can see in this print of a classification report they are defined for each class. They rely on concepts such as true positives or false negative that require defining which class is the positive one.

             precision    recall  f1-score   support

          0       0.65      1.00      0.79        17
          1       0.57      0.75      0.65        16
          2       0.33      0.06      0.10        17
avg / total       0.52      0.60      0.51        50

The warning

F1 score:/usr/local/lib/python2.7/site-packages/sklearn/metrics/classification.py:676: DeprecationWarning: The 
default `weighted` averaging is deprecated, and from version 0.18, 
use of precision, recall or F-score with multiclass or multilabel data  
or pos_label=None will result in an exception. Please set an explicit 
value for `average`, one of (None, 'micro', 'macro', 'weighted', 
'samples'). In cross validation use, for instance, 
scoring="f1_weighted" instead of scoring="f1".

You get this warning because you are using the f1-score, recall and precision without defining how they should be computed! The question could be rephrased: from the above classification report, how do you output one global number for the f1-score? You could:

Take the average of the f1-score for each class: that's the avg / total result above. It's also called macro averaging.
Compute the f1-score using the global count of true positives / false negatives, etc. (you sum the number of true positives / false negatives for each class). Aka micro averaging.
Compute a weighted average of the f1-score. Using 'weighted' in scikit-learn will weigh the f1-score by the support of the class: the more elements a class has, the more important the f1-score for this class in the computation.

These are 3 of the options in scikit-learn, the warning is there to say you have to pick one. So you have to specify an average argument for the score method.

Which one you choose is up to how you want to measure the performance of the classifier: for instance macro-averaging does not take class imbalance into account and the f1-score of class 1 will be just as important as the f1-score of class 5. If you use weighted averaging however you'll get more importance for the class 5.

The whole argument specification in these metrics is not super-clear in scikit-learn right now, it will get better in version 0.18 according to the docs. They are removing some non-obvious standard behavior and they are issuing warnings so that developers notice it.

Computing scores

Last thing I want to mention (feel free to skip it if you're aware of it) is that scores are only meaningful if they are computed on data that the classifier has never seen. This is extremely important as any score you get on data that was used in fitting the classifier is completely irrelevant.

Here's a way to do it using StratifiedShuffleSplit, which gives you a random splits of your data (after shuffling) that preserve the label distribution.

from sklearn.datasets import make_classification
from sklearn.cross_validation import StratifiedShuffleSplit
from sklearn.metrics import accuracy_score, f1_score, precision_score, recall_score, classification_report, confusion_matrix

# We use a utility to generate artificial classification data.
X, y = make_classification(n_samples=100, n_informative=10, n_classes=3)
sss = StratifiedShuffleSplit(y, n_iter=1, test_size=0.5, random_state=0)
for train_idx, test_idx in sss:
    X_train, X_test, y_train, y_test = X[train_idx], X[test_idx], y[train_idx], y[test_idx]
    svc.fit(X_train, y_train)
    y_pred = svc.predict(X_test)
    print(f1_score(y_test, y_pred, average="macro"))
    print(precision_score(y_test, y_pred, average="macro"))
    print(recall_score(y_test, y_pred, average="macro"))

Hope this helps.

How to get screen width and height

WindowManager w = getWindowManager();
Display d = w.getDefaultDisplay();
DisplayMetrics metrics = new DisplayMetrics();
d.getMetrics(metrics);

Log.d("WIDTH: ", String.valueOf(d.getWidth()));
Log.d("HEIGHT: ", String.valueOf(d.getHeight()));

Received fatal alert: handshake_failure through SSLHandshakeException

Disclaimer : I am not aware if the answer will be helpful for many people,just sharing because it might .

I was getting this error while using Parasoft SOATest to send request XML(SOAP) .

The issue was that I had selected the wrong alias from the dropdown after adding the certificate and authenticating it.

What's the difference between ngOnInit and ngAfterViewInit of Angular2?

Content is what is passed as children. View is the template of the current component.

The view is initialized before the content and ngAfterViewInit() is therefore called before ngAfterContentInit().

** ngAfterViewInit() is called when the bindings of the children directives (or components) have been checked for the first time. Hence its perfect for accessing and manipulating DOM with Angular 2 components. As @Günter Zöchbauer mentioned before is correct @ViewChild() hence runs fine inside it.

Example:

@Component({
    selector: 'widget-three',
    template: `<input #input1 type="text">`
})
export class WidgetThree{
    @ViewChild('input1') input1;

    constructor(private renderer:Renderer){}

    ngAfterViewInit(){
        this.renderer.invokeElementMethod(
            this.input1.nativeElement,
            'focus',
            []
        )
    }
}

Recover sa password

The best way is to simply reset the password by connecting with a domain/local admin (so you may need help from your system administrators), but this only works if SQL Server was set up to allow local admins (these are now left off the default admin group during setup).

If you can't use this or other existing methods to recover / reset the SA password, some of which are explained here:

Then you could always backup your important databases, uninstall SQL Server, and install a fresh instance.

You can also search for less scrupulous ways to do it (e.g. there are password crackers that I am not enthusiastic about sharing).

As an aside, the login properties for sa would never say Windows Authentication. This is by design as this is a SQL Authentication account. This does not mean that Windows Authentication is disabled at the instance level (in fact it is not possible to do so), it just doesn't apply for a SQL auth account.

I wrote a tip on using PSExec to connect to an instance using the NT AUTHORITY\SYSTEM account (which works < SQL Server 2012), and a follow-up that shows how to hack the SqlWriter service (which can work on more modern versions):

And some other resources:

Facebook API: Get fans of / people who like a page

Facebook's FQL documentation here tells you how to do it. Run the example SELECT name, fan_count FROM page WHERE page_id = 19292868552 and replace the page_id number with your page's id number and it will return the page name and the fan count.

How do I get the web page contents from a WebView?

I know this is a late answer, but I found this question because I had the same problem. I think I found the answer in this post on lexandera.com. The code below is basically a cut-and-paste from the site. It seems to do the trick.

final Context myApp = this;

/* An instance of this class will be registered as a JavaScript interface */
class MyJavaScriptInterface
{
    @JavascriptInterface
    @SuppressWarnings("unused")
    public void processHTML(String html)
    {
        // process the html as needed by the app
    }
}

final WebView browser = (WebView)findViewById(R.id.browser);
/* JavaScript must be enabled if you want it to work, obviously */
browser.getSettings().setJavaScriptEnabled(true);

/* Register a new JavaScript interface called HTMLOUT */
browser.addJavascriptInterface(new MyJavaScriptInterface(), "HTMLOUT");

/* WebViewClient must be set BEFORE calling loadUrl! */
browser.setWebViewClient(new WebViewClient() {
    @Override
    public void onPageFinished(WebView view, String url)
    {
        /* This call inject JavaScript into the page which just finished loading. */
        browser.loadUrl("javascript:window.HTMLOUT.processHTML('<head>'+document.getElementsByTagName('html')[0].innerHTML+'</head>');");
    }
});

/* load a web page */
browser.loadUrl("http://lexandera.com/files/jsexamples/gethtml.html");

Reading local text file into a JavaScript array

Using Node.js

sync mode:

var fs = require("fs");
var text = fs.readFileSync("./mytext.txt");
var textByLine = text.split("\n")

async mode:

var fs = require("fs");
fs.readFile("./mytext.txt", function(text){
    var textByLine = text.split("\n")
});

UPDATE

As of at least Node 6, readFileSync returns a Buffer, so it must first be converted to a string in order for split to work:

var text = fs.readFileSync("./mytext.txt").toString('utf-8');

var text = fs.readFileSync("./mytext.txt", "utf-8");

Substring a string from the end of the string

string s = "Hello Marco !";
s = s.Remove(s.length - 2, 2);

How do I use reflection to invoke a private method?

Could you not just have a different Draw method for each type that you want to Draw? Then call the overloaded Draw method passing in the object of type itemType to be drawn.

Your question does not make it clear whether itemType genuinely refers to objects of differing types.

How to clear a data grid view

dataGridView1.Rows.Clear();
dataGridView1.Refresh();

Android: How can I print a variable on eclipse console?

By the way, in case you dont know what is the exact location of your JSONObject inside your JSONArray i suggest using the following code: (I assumed that "jsonArray" is your main variable with all the data, and i'm searching the exact object inside the array with equals function)

    JSONArray list = new JSONArray(); 
    if (jsonArray != null){
        int len = jsonArray.length();
        for (int i=0;i<len;i++)
        { 
            boolean flag;
            try {
                flag = jsonArray.get(i).toString().equals(obj.toString());
                //Excluding the item at position
                if (!flag) 
                {
                    list.put(jsonArray.get(i));
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }  
        } 
    }
    jsonArray = list;

Exit Shell Script Based on Process Exit Code

If you just call exit in Bash without any parameters, it will return the exit code of the last command. Combined with OR, Bash should only invoke exit, if the previous command fails. But I haven't tested this.

command1 || exit;
command2 || exit;

Bash will also store the exit code of the last command in the variable $?.

Timer Interval 1000 != 1 second?

Instead of Tick event, use Elapsed event.

timer.Elapsed += new EventHandler(TimerEventProcessor);

and change the signiture of TimerEventProcessor method;

private void TimerEventProcessor(object sender, ElapsedEventArgs e)
{
  label1.Text = _counter.ToString();
  _counter += 1;
}

How can I get the current network interface throughput statistics on Linux/UNIX?

nload is a great tool for monitoring bandwidth in real time and easily installed in Ubuntu or Debian with sudo apt-get install nload.

Device eth0 [10.10.10.5] (1/2):
=====================================================================================
Incoming:


                               .         ...|    
                               #         ####|   
                           .. |#|  ...   #####.         ..          Curr: 2.07 MBit/s
                          ###.###  #### #######|.     . ##      |   Avg: 1.41 MBit/s
                         ########|#########################.   ###  Min: 1.12 kBit/s
             ........    ###################################  .###  Max: 4.49 MBit/s
           .##########. |###################################|#####  Ttl: 1.94 GByte
Outgoing:
            ##########  ###########    ###########################
            ##########  ###########    ###########################
            ##########. ###########   .###########################
            ########### ###########  #############################
            ########### ###########..#############################
           ############ ##########################################
           ############ ##########################################
           ############ ##########################################  Curr: 63.88 MBit/s
           ############ ##########################################  Avg: 32.04 MBit/s
           ############ ##########################################  Min: 0.00 Bit/s
           ############ ##########################################  Max: 93.23 MBit/s
         ############## ##########################################  Ttl: 2.49 GByte

Another excellent tool is iftop, also easily apt-get'able:

             191Mb      381Mb                 572Mb       763Mb             954Mb     
+--------------------------------------------------------------------------------
box4.local            => box-2.local                      91.0Mb  27.0Mb  15.1Mb
                      <=                                  1.59Mb   761kb   452kb
box4.local            => box.local                         560b   26.8kb  27.7kb
                      <=                                   880b   31.3kb  32.1kb
box4.local            => userify.com                         0b   11.4kb  8.01kb
                      <=                                  1.17kb  2.39kb  1.75kb
box4.local            => b.resolvers.Level3.net              0b     58b    168b
                      <=                                     0b     83b    288b
box4.local            => stackoverflow.com                   0b     42b     21b
                      <=                                     0b     42b     21b
box4.local            => 224.0.0.251                         0b      0b    179b
                      <=                                     0b      0b      0b
224.0.0.251           => box-2.local                         0b      0b      0b
                      <=                                     0b      0b     36b
224.0.0.251           => box.local                           0b      0b      0b
                      <=                                     0b      0b     35b


---------------------------------------------------------------------------------
TX:           cum:   37.9MB   peak:   91.0Mb     rates:   91.0Mb  27.1Mb  15.2Mb
RX:                  1.19MB           1.89Mb              1.59Mb   795kb   486kb
TOTAL:               39.1MB           92.6Mb              92.6Mb  27.9Mb  15.6Mb

Don't forget about the classic and powerful sar and netstat utilities on older *nix!

How to get the Facebook user id using the access token

If you want to use Graph API to get current user ID then just send a request to:

https://graph.facebook.com/me?access_token=...

How to select data from 30 days?

Short version for easy use:

SELECT * 
FROM [TableName] t
WHERE t.[DateColumnName] >= DATEADD(month, -1, GETDATE())

DATEADD and GETDATE are available in SQL Server starting with 2008 version. MSDN documentation: GETDATE and DATEADD.

How can I restore the MySQL root user’s full privileges?

Just insert or update mysql.user with value Y in each column privileges.

MySQL - select data from database between two dates

Another alternative is to use DATE() function on the left hand operand as shown below

SELECT users.* FROM users WHERE DATE(created_at) BETWEEN '2011-12-01' AND '2011-12-06'

How to check whether an array is empty using PHP?

Some decent answers, but just thought I'd expand a bit to explain more clearly when PHP determines if an array is empty.

Main Notes:

An array with a key (or keys) will be determined as NOT empty by PHP.

As array values need keys to exist, having values or not in an array doesn't determine if it's empty, only if there are no keys (AND therefore no values).

So checking an array with empty() doesn't simply tell you if you have values or not, it tells you if the array is empty, and keys are part of an array.

So consider how you are producing your array before deciding which checking method to use.
EG An array will have keys when a user submits your HTML form when each form field has an array name (ie name="array[]").
A non empty array will be produced for each field as there will be auto incremented key values for each form field's array.

Take these arrays for example:

/* Assigning some arrays */

// Array with user defined key and value
$ArrayOne = array("UserKeyA" => "UserValueA", "UserKeyB" => "UserValueB");

// Array with auto increment key and user defined value
// as a form field would return with user input
$ArrayTwo[] = "UserValue01";
$ArrayTwo[] = "UserValue02";

// Array with auto incremented key and no value
// as a form field would return without user input
$ArrayThree[] = '';
$ArrayThree[] = '';

If you echo out the array keys and values for the above arrays, you get the following:

ARRAY ONE:
[UserKeyA] => [UserValueA]
[UserKeyB] => [UserValueB]

ARRAY TWO:
[0] => [UserValue01]
[1] => [UserValue02]

ARRAY THREE:
[0] => []
[1] => []

And testing the above arrays with empty() returns the following results:

ARRAY ONE:
$ArrayOne is not empty

ARRAY TWO:
$ArrayTwo is not empty

ARRAY THREE:
$ArrayThree is not empty

An array will always be empty when you assign an array but don't use it thereafter, such as:

$ArrayFour = array();

This will be empty, ie PHP will return TRUE when using if empty() on the above.

So if your array has keys - either by eg a form's input names or if you assign them manually (ie create an array with database column names as the keys but no values/data from the database), then the array will NOT be empty().

In this case, you can loop the array in a foreach, testing if each key has a value. This is a good method if you need to run through the array anyway, perhaps checking the keys or sanitising data.

However it is not the best method if you simply need to know "if values exist" returns TRUE or FALSE. There are various methods to determine if an array has any values when it's know it will have keys. A function or class might be the best approach, but as always it depends on your environment and exact requirements, as well as other things such as what you currently do with the array (if anything).

Here's an approach which uses very little code to check if an array has values:

Using array_filter():
Iterates over each value in the array passing them to the callback function. If the callback function returns true, the current value from array is returned into the result array. Array keys are preserved.

$EmptyTestArray = array_filter($ArrayOne);

if (!empty($EmptyTestArray))
  {
    // do some tests on the values in $ArrayOne
  }
else
  {
    // Likely not to need an else, 
    // but could return message to user "you entered nothing" etc etc
  }

Running array_filter() on all three example arrays (created in the first code block in this answer) results in the following:

ARRAY ONE:
$arrayone is not empty

ARRAY TWO:
$arraytwo is not empty

ARRAY THREE:
$arraythree is empty

So when there are no values, whether there are keys or not, using array_filter() to create a new array and then check if the new array is empty shows if there were any values in the original array.
It is not ideal and a bit messy, but if you have a huge array and don't need to loop through it for any other reason, then this is the simplest in terms of code needed.

I'm not experienced in checking overheads, but it would be good to know the differences between using array_filter() and foreach checking if a value is found.

Obviously benchmark would need to be on various parameters, on small and large arrays and when there are values and not etc.

HashMap allows duplicates?

HashMap don't allow duplicate keys,but since it's not thread safe,it might occur duplicate keys. eg:

 while (true) {
            final HashMap<Object, Object> map = new HashMap<Object, Object>(2);
            map.put("runTimeType", 1);
            map.put("title", 2);
            map.put("params", 3);
            final AtomicInteger invokeCounter = new AtomicInteger();

            for (int i = 0; i < 100; i++) {
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        map.put("formType", invokeCounter.incrementAndGet());
                    }
                }).start();
            }
            while (invokeCounter.intValue() != 100) {
                Thread.sleep(10);
            }
            if (map.size() > 4) {
// this means you insert two or more formType key to the map
               System.out.println( JSONObject.fromObject(map));
            }
        }

What is the symbol for whitespace in C?

The ASCII value of Space is 32. So you can compare your char to the octal value of 32 which is 40 or its hexadecimal value which is 20.

if(c == '\40') { ... }

if(c == '\x20') { ... }

Any number after the \ is assumed to be octal, if the character just after \ is not x, in which case it is considered to be a hexadecimal.

Make a table fill the entire window

This works fine for me:

_x000D_

<style type="text/css">_x000D_
#table {_x000D_
 position: absolute;_x000D_
 top: 0;_x000D_
 bottom: 0;_x000D_
 left: 0;_x000D_
 right: 0;_x000D_
 height: 100%;_x000D_
 width: 100%;_x000D_
}_x000D_
</style>

_x000D_

For me, just changing Height and Width to 100% doesn’t do it for me, and neither do setting left, right, top and bottom to 0, but using them both together will do the trick.

javax.naming.NoInitialContextException - Java

If working on EJB client library:

You need to mention the argument for getting the initial context.

InitialContext ctx = new InitialContext();

If you do not, it will look in the project folder for properties file. Also you can include the properties credentials or values in your class file itself as follows:

Properties props = new Properties();
props.put(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");
props.put(Context.URL_PKG_PREFIXES, "org.jboss.ejb.client.naming");
props.put(Context.PROVIDER_URL, "jnp://localhost:1099");

InitialContext ctx = new InitialContext(props);

URL_PKG_PREFIXES: Constant that holds the name of the environment property for specifying the list of package prefixes to use when loading in URL context factories.

The EJB client library is the primary library to invoke remote EJB components.
This library can be used through the InitialContext. To invoke EJB components the library creates an EJB client context via a URL context factory. The only necessary configuration is to parse the value org.jboss.ejb.client.naming for the java.naming.factory.url.pkgs property to instantiate an InitialContext.

Inserting image into IPython notebook markdown

Most of the answers given so far go in the wrong direction, suggesting to load additional libraries and use the code instead of markup. In Ipython/Jupyter Notebooks it is very simple. Make sure the cell is indeed in markup and to display a image use:

![alt text](imagename.png "Title")

Further advantage compared to the other methods proposed is that you can display all common file formats including jpg, png, and gif (animations).

Using variables inside strings

Up to C#5 (-VS2013) you have to call a function/method for it. Either a "normal" function such as String.Format or an overload of the + operator.

string str = "Hello " + name; // This calls an overload of operator +.

In C#6 (VS2015) string interpolation has been introduced (as described by other answers).

Click button copy to clipboard using jQuery

Most of the proposed answers create an extra temporary hidden input element(s). Because most browsers nowadays support div content edit, I propose a solution that does not create hidden element(s), preserve text formatting and use pure JavaScript or jQuery library.

Here is a minimalist skeleton implementation using the fewest lines of codes I could think of:

_x000D_

//Pure javascript implementation:_x000D_
document.getElementById("copyUsingPureJS").addEventListener("click", function() {_x000D_
  copyUsingPureJS(document.getElementById("copyTarget"));_x000D_
  alert("Text Copied to Clipboard Using Pure Javascript");_x000D_
});_x000D_
_x000D_
function copyUsingPureJS(element_id) {_x000D_
  element_id.setAttribute("contentEditable", true);_x000D_
  element_id.setAttribute("onfocus", "document.execCommand('selectAll',false,null)");_x000D_
  element_id.focus();_x000D_
  document.execCommand("copy");_x000D_
  element_id.removeAttribute("contentEditable");_x000D_
  _x000D_
}_x000D_
_x000D_
//Jquery:_x000D_
$(document).ready(function() {_x000D_
  $("#copyUsingJquery").click(function() {_x000D_
    copyUsingJquery("#copyTarget");_x000D_
  });_x000D_
 _x000D_
_x000D_
  function copyUsingJquery(element_id) {_x000D_
    $(element_id).attr("contenteditable", true)_x000D_
      .select()_x000D_
      .on("focus", function() {_x000D_
        document.execCommand('selectAll', false, null)_x000D_
      })_x000D_
      .focus()_x000D_
    document.execCommand("Copy");_x000D_
    $(element_id).removeAttr("contenteditable");_x000D_
     alert("Text Copied to Clipboard Using jQuery");_x000D_
  }_x000D_
});

_x000D_

#copyTarget {_x000D_
  width: 400px;_x000D_
  height: 400px;_x000D_
  border: 1px groove gray;_x000D_
  color: navy;_x000D_
  text-align: center;_x000D_
  box-shadow: 0 4px 8px 0 gray;_x000D_
}_x000D_
_x000D_
#copyTarget h1 {_x000D_
  color: blue;_x000D_
}_x000D_
_x000D_
#copyTarget h2 {_x000D_
  color: red;_x000D_
}_x000D_
_x000D_
#copyTarget h3 {_x000D_
  color: green;_x000D_
}_x000D_
_x000D_
#copyTarget h4 {_x000D_
  color: cyan;_x000D_
}_x000D_
_x000D_
#copyTarget h5 {_x000D_
  color: brown;_x000D_
}_x000D_
_x000D_
#copyTarget h6 {_x000D_
  color: teal;_x000D_
}_x000D_
_x000D_
#pasteTarget {_x000D_
  width: 400px;_x000D_
  height: 400px;_x000D_
  border: 1px inset skyblue;_x000D_
}

_x000D_

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<div id="copyTarget">_x000D_
  <h1>Heading 1</h1>_x000D_
  <h2>Heading 2</h2>_x000D_
  <h3>Heading 3</h3>_x000D_
  <h4>Heading 4</h4>_x000D_
  <h5>Heading 5</h5>_x000D_
  <h6>Heading 6</h6>_x000D_
  <strong>Preserve <em>formatting</em></strong>_x000D_
  <br/>_x000D_
</div>_x000D_
_x000D_
<button id="copyUsingPureJS">Copy Using Pure JavaScript</button>_x000D_
<button id="copyUsingJquery">Copy Using jQuery</button>_x000D_
<br><br> Paste Here to See Result_x000D_
<div id="pasteTarget" contenteditable="true"></div>

_x000D_

What can cause intermittent ORA-12519 (TNS: no appropriate handler found) errors

Don't know if this will be everybody's answer, but after some digging, here's what we came up with.

The error is obviously caused by the fact that the listener was not accepting connections, but why would we get that error when other tests could connect fine (we could also connect no problem through sqlplus)? The key to the issue wasn't that we couldn't connect, but that it was intermittent

After some investigation, we found that there was some static data created during the class setup that would keep open connections for the life of the test class, creating new ones as it went. Now, even though all of the resources were properly released when this class went out of scope (via a finally{} block, of course), there were some cases during the run when this class would swallow up all available connections (okay, bad practice alert - this was unit test code that connected directly rather than using a pool, so the same problem could not happen in production).

The fix was to not make that class static and run in the class setup, but instead use it in the per method setUp and tearDown methods.

So if you get this error in your own apps, slap a profiler on that bad boy and see if you might have a connection leak. Hope that helps.

Remove a CLASS for all child elements

You can also do like this :

  $("#table-filters li").parent().find('li').removeClass("active");

What exactly is Apache Camel?

Apache Camel is a Java framework for Enterprise integration. Eg:- if you are building a web application which interacts with many vendor API's we can use the camel as the External integration tool. We can do more with it based on the use case. Camel in Action from Manning publications is a great book for learning Camel. The integrations can be defined as below.

Java DSL

from("jetty://0.0.0.0:8080/searchProduct").routeId("searchProduct.products").threads()
    .log(LoggingLevel.INFO, "searchProducts request Received with body: ${body}")
    .bean(Processor.class, "createSearchProductsRequest").removeHeaders("CamelHttp*")
    .setHeader(Exchange.HTTP_METHOD, constant(org.apache.camel.component.http4.HttpMethods.POST))
    .to("http4://" + preLiveBaseAPI + searchProductsUrl + "?apiKey=" + ApiKey
                    + "&bridgeEndpoint=true")
    .bean(Processor.class, "buildResponse").log(LoggingLevel.INFO, "Search products finished");

This is to just create a REST API endpoint which in turn calls an external API and sends the request back

Spring DSL

<route id="GROUPS-SHOW">
    <from uri="jetty://0.0.0.0:8080/showGroups" />
    <log loggingLevel="INFO" message="Reqeust receviced service to fetch groups -> ${body}" />
    <to uri="direct:auditLog" />
    <process ref="TestProcessor" />
</route>

Coming to your questions

What exactly is it? Ans:- It is a framework which implements Enterprise integration patterns
How does it interact with an application written in Java? Ans:- it can interact with any available protocols like http, ftp, amqp etc
Is it something that goes together with the server? Ans:- It can be deployed in a container like tomcat or can be deployed independently as a java process
Is it an independent program? Ans:- It can be.

Hope it helps

Convert a 1D array to a 2D array in numpy

Try something like:

B = np.reshape(A,(-1,ncols))

You'll need to make sure that you can divide the number of elements in your array by ncols though. You can also play with the order in which the numbers are pulled into B using the order keyword.

POST Multipart Form Data using Retrofit 2.0 including image

Uploading Files using Retrofit is Quite Simple You need to build your api interface as

public interface Api {

    String BASE_URL = "http://192.168.43.124/ImageUploadApi/";


    @Multipart
    @POST("yourapipath")
    Call<MyResponse> uploadImage(@Part("image\"; filename=\"myfile.jpg\" ") RequestBody file, @Part("desc") RequestBody desc);

}

in the above code image is the key name so if you are using php you will write $_FILES['image']['tmp_name'] to get this. And filename="myfile.jpg" is the name of your file that is being sent with the request.

Now to upload the file you need a method that will give you the absolute path from the Uri.

private String getRealPathFromURI(Uri contentUri) {
    String[] proj = {MediaStore.Images.Media.DATA};
    CursorLoader loader = new CursorLoader(this, contentUri, proj, null, null, null);
    Cursor cursor = loader.loadInBackground();
    int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
    cursor.moveToFirst();
    String result = cursor.getString(column_index);
    cursor.close();
    return result;
}

Now you can use the below code to upload your file.

 private void uploadFile(Uri fileUri, String desc) {

        //creating a file
        File file = new File(getRealPathFromURI(fileUri));

        //creating request body for file
        RequestBody requestFile = RequestBody.create(MediaType.parse(getContentResolver().getType(fileUri)), file);
        RequestBody descBody = RequestBody.create(MediaType.parse("text/plain"), desc);

        //The gson builder
        Gson gson = new GsonBuilder()
                .setLenient()
                .create();


        //creating retrofit object
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(Api.BASE_URL)
                .addConverterFactory(GsonConverterFactory.create(gson))
                .build();

        //creating our api 
        Api api = retrofit.create(Api.class);

        //creating a call and calling the upload image method 
        Call<MyResponse> call = api.uploadImage(requestFile, descBody);

        //finally performing the call 
        call.enqueue(new Callback<MyResponse>() {
            @Override
            public void onResponse(Call<MyResponse> call, Response<MyResponse> response) {
                if (!response.body().error) {
                    Toast.makeText(getApplicationContext(), "File Uploaded Successfully...", Toast.LENGTH_LONG).show();
                } else {
                    Toast.makeText(getApplicationContext(), "Some error occurred...", Toast.LENGTH_LONG).show();
                }
            }

            @Override
            public void onFailure(Call<MyResponse> call, Throwable t) {
                Toast.makeText(getApplicationContext(), t.getMessage(), Toast.LENGTH_LONG).show();
            }
        });
    }

For more detailed explanation you can visit this Retrofit Upload File Tutorial.

Can't update: no tracked branch

I have faced The same problem So I used the Git directly to push the project to GitHub.

In your android studio

Go to VCS=>Git=> Push: use the Branch Name You Commit and hit Push Button

Note: tested for android studio version 3.3

Eclipse shows errors but I can't find them

I had a red X on a folder, but not on any of the files inside it. The only thing that fixed it was clicking and dragging some of the files from the problem folder into another folder, and then performing Maven -> Update Project. I could then drag the files back without the red X returning.

error: RPC failed; curl transfer closed with outstanding read data remaining

Simple Solution: Rather then cloning via https, clone it via ssh.

For example:

git clone https://github.com/vaibhavjain2/xxx.git - Avoid
git clone [email protected]:vaibhavjain2/xxx.git - Correct

Can't fix Unsupported major.minor version 52.0 even after fixing compatibility

I had the same issue. Turned out I used some external jars (apache poi 4.1.2) which were compiled with 1.8. Solved it by changing Java Build Path JRE to 1.8.

How to get the html of a div on another page with jQuery ajax?

$.ajax({
  url:href,
  type:'get',
  success: function(data){
   console.log($(data)); 
  }
});

This console log gets an array like object: [meta, title, ,], very strange

You can use JavaScript:

var doc = document.documentElement.cloneNode()
doc.innerHTML = data
$content = $(doc.querySelector('#content'))

How to open the Google Play Store directly from my Android application?

Some of the answers to this question are outdated.

What worked for me (in 2020) was to explicitly tell the intent to skip the chooser and directly open the play store app, according to this link:

"If you want to link to your products from an Android app, create an Intent that opens a URL. As you configure this intent, pass "com.android.vending" into Intent.setPackage() so that users see your app's details in the Google Play Store app instead of a chooser."

This is the Kotlin code I used to direct users to viewing the app containing the package name com.google.android.apps.maps in Google Play:

val intent = Intent(Intent.ACTION_VIEW).apply {
               data = Uri.parse("http://play.google.com/store/apps/details?id=com.google.android.apps.maps")
               setPackage("com.android.vending")
            }
            startActivity(intent)

I hope that helps someone!

How to set value in @Html.TextBoxFor in Razor syntax?

I tried replacing value with Value and it worked out. It has set the value in input tag now.

Responsive css styles on mobile devices ONLY

I had to solve a similar problem--I wanted certain styles to only apply to mobile devices in landscape mode. Essentially the fonts and line spacing looked fine in every other context, so I just needed the one exception for mobile landscape. This media query worked perfectly:

@media all and (max-width: 600px) and (orientation:landscape) 
{
    /* styles here */
}

How can I conditionally import an ES6 module?

If you'd like, you could use require. This is a way to have a conditional require statement.

let something = null;
let other = null;

if (condition) {
    something = require('something');
    other = require('something').other;
}
if (something && other) {
    something.doStuff();
    other.doOtherStuff();
}

How to run single test method with phpunit?

You must use --filter to run a single test method php phpunit --filter "/::testMethod( .*)?$/" ClassTest ClassTest.php

The above filter will run testMethod alone.

How to prove that a problem is NP complete?

To show a problem is NP complete, you need to:

Show it is in NP

In other words, given some information C, you can create a polynomial time algorithm V that will verify for every possible input X whether X is in your domain or not.

Example

Prove that the problem of vertex covers (that is, for some graph G, does it have a vertex cover set of size k such that every edge in G has at least one vertex in the cover set?) is in NP:

our input X is some graph G and some number k (this is from the problem definition)
Take our information C to be "any possible subset of vertices in graph G of size k"
Then we can write an algorithm V that, given G, k and C, will return whether that set of vertices is a vertex cover for G or not, in polynomial time.

Then for every graph G, if there exists some "possible subset of vertices in G of size k" which is a vertex cover, then G is in NP.

Note that we do not need to find C in polynomial time. If we could, the problem would be in `P.

Note that algorithm V should work for every G, for some C. For every input there should exist information that could help us verify whether the input is in the problem domain or not. That is, there should not be an input where the information doesn't exist.

Prove it is NP Hard

This involves getting a known NP-complete problem like SAT, the set of boolean expressions in the form:

(A or B or C) and (D or E or F) and ...

where the expression is satisfiable, that is there exists some setting for these booleans, which makes the expression true.

Then reduce the NP-complete problem to your problem in polynomial time.

That is, given some input X for SAT (or whatever NP-complete problem you are using), create some input Y for your problem, such that X is in SAT if and only if Y is in your problem. The function f : X -> Y must run in polynomial time.

In the example above, the input Y would be the graph G and the size of the vertex cover k.

For a full proof, you'd have to prove both:

that X is in SAT => Y in your problem
and Y in your problem => X in SAT.

marcog's answer has a link with several other NP-complete problems you could reduce to your problem.

Footnote: In step 2 (Prove it is NP-hard), reducing another NP-hard (not necessarily NP-complete) problem to the current problem will do, since NP-complete problems are a subset of NP-hard problems (that are also in NP).

How to create a shared library with cmake?

This minimal CMakeLists.txt file compiles a simple shared library:

cmake_minimum_required(VERSION 2.8)

project (test)
set(CMAKE_BUILD_TYPE Release)

include_directories(${CMAKE_CURRENT_SOURCE_DIR}/include)
add_library(test SHARED src/test.cpp)

However, I have no experience copying files to a different destination with CMake. The file command with the COPY/INSTALL signature looks like it might be useful.

How can I keep my branch up to date with master with git?

If your branch is local only and hasn't been pushed to the server, use

git rebase master

Otherwise, use

git merge master

How to work offline with TFS

The 'Go Offline' extension adds a button to the Source Control menu.

https://visualstudiogallery.msdn.microsoft.com/6e54271c-2c4e-4911-a1b4-a65a588ae138

When to use SELECT ... FOR UPDATE?

Short answers:

Q1: Yes.

Q2: Doesn't matter which you use.

Long answer:

A select ... for update will (as it implies) select certain rows but also lock them as if they have already been updated by the current transaction (or as if the identity update had been performed). This allows you to update them again in the current transaction and then commit, without another transaction being able to modify these rows in any way.

Another way of looking at it, it is as if the following two statements are executed atomically:

select * from my_table where my_condition;

update my_table set my_column = my_column where my_condition;

Since the rows affected by my_condition are locked, no other transaction can modify them in any way, and hence, transaction isolation level makes no difference here.

Note also that transaction isolation level is independent of locking: setting a different isolation level doesn't allow you to get around locking and update rows in a different transaction that are locked by your transaction.

What transaction isolation levels do guarantee (at different levels) is the consistency of data while transactions are in progress.

Inserting the iframe into react component

If you don't want to use dangerouslySetInnerHTML then you can use the below mentioned solution

var Iframe = React.createClass({     
  render: function() {
    return(         
      <div>          
        <iframe src={this.props.src} height={this.props.height} width={this.props.width}/>         
      </div>
    )
  }
});

ReactDOM.render(
  <Iframe src="http://plnkr.co/" height="500" width="500"/>,
  document.getElementById('example')
);

here live demo is available Demo

Cannot inline bytecode built with JVM target 1.8 into bytecode that is being built with JVM target 1.6

Using the Kotlin Gradle DSL, this solved the issue for me. I added this to the build.gradle.kts. This is in addition to the answer by Joel

val compileKotlin: KotlinCompile by tasks
compileKotlin.kotlinOptions.jvmTarget = JavaVersion.VERSION_1_8.toString()

What is the worst programming language you ever worked with?

ABAP

It's used to program applications for SAP. And it's bad.

How to access a DOM element in React? What is the equilvalent of document.getElementById() in React

Since React uses JSX code to create an HTML we cannot refer dom using regulation methods like documment.querySelector or getElementById.

Instead we can use React ref system to access and manipulate Dom as shown in below example:

constructor(props){

    super(props);
    this.imageRef = React.createRef(); // create react ref
}

componentDidMount(){

    **console.log(this.imageRef)** // acessing the attributes of img tag when dom loads
}


render = (props) => {

const {urls,description} = this.props.image;
    return (

            <img
             **ref = {this.imageRef} // assign the ref of img tag here**
             src = {urls.regular} 
             alt = {description}
             />

        );

}

}

How can I convert a VBScript to an executable (EXE) file?

Here are a couple possible solutions...

I have not tried all of these myself yet, but I will be trying them all soon.

Note: I do not have any personal or financial connection to any of these tools.

1) VB Script to EXE Converter (NOT Compiler): (Free)
vbs2exe.com.

The exe produced appears to be a true EXE.

From their website:

VBS to EXE is a free online converter that doesn't only convert your vbs files into exe but it also:

1- Encrypt your vbs file source code using 128 bit key.
2- Allows you to call win32 API
3- If you have troubles with windows vista especially when UAC is enabled then you may give VBS to EXE a try.
4- No need for wscript.exe to run your vbs anymore.
5- Your script is never saved to the hard disk like some others converters. it is a TRUE exe not an extractor.

This solution should work even if wscript/cscript is not installed on the computer.

Basically, this creates a true .EXE file. Inside the created .EXE is an "engine" that replaces wscript/cscript, and an encrypted copy of your VB Script code. This replacement engine executes your code IN MEMORY without calling wscript/cscript to do it.

2) Compile and Convert VBS to EXE...:
ExeScript

The current version is 3.5.

This is NOT a Free solution. They have a 15 day trial. After that, you need to buy a license for a hefty $44.96 (Home License/noncommercial), or $89.95 (Business License/commercial usage).

It seems to work in a similar way to the previous solution.

According to a forum post there:
Post: "A Exe file still need Windows Scripting Host (WSH) ??"

WSH is not required if "Compile" option was used, since ExeScript
implements it's own scripting host. ...

3) Encrypt the script with Microsoft's ".vbs to .vbe" encryption tool.

Apparently, this does not work for Windows 7/8, and it is possible there are ways to "decrypt" the .vbe file. At the time of writing this, I could not find a working link to download this. If I find one, I will add it to this answer.

What is the best workaround for the WCF client `using` block issue?

@Marc Gravell

Wouldn't it be OK to use this:

public static TResult Using<T, TResult>(this T client, Func<T, TResult> work)
        where T : ICommunicationObject
{
    try
    {
        var result = work(client);

        client.Close();

        return result;
    }
    catch (Exception e)
    {
        client.Abort();

        throw;
    }
}

Or, the same thing (Func<T, TResult>) in case of Service<IOrderService>.Use

These would make returning variables easier.

What encoding/code page is cmd.exe using?

To answer your second query re. how encoding works, Joel Spolsky wrote a great introductory article on this. Strongly recommended.

How can I parse a YAML file from a Linux shell script?

I've written shyaml in python for YAML query needs from the shell command line.

Overview:

$ pip install shyaml      ## installation

Example's YAML file (with complex features):

$ cat <<EOF > test.yaml
name: "MyName !!"
subvalue:
    how-much: 1.1
    things:
        - first
        - second
        - third
    other-things: [a, b, c]
    maintainer: "Valentin Lab"
    description: |
        Multiline description:
        Line 1
        Line 2
EOF

Basic query:

$ cat test.yaml | shyaml get-value subvalue.maintainer
Valentin Lab

More complex looping query on complex values:

$ cat test.yaml | shyaml values-0 | \
  while read -r -d $'\0' value; do
      echo "RECEIVED: '$value'"
  done
RECEIVED: '1.1'
RECEIVED: '- first
- second
- third'
RECEIVED: '2'
RECEIVED: 'Valentin Lab'
RECEIVED: 'Multiline description:
Line 1
Line 2'

A few key points:

all YAML types and syntax oddities are correctly handled, as multiline, quoted strings, inline sequences...
\0 padded output is available for solid multiline entry manipulation.
simple dotted notation to select sub-values (ie: subvalue.maintainer is a valid key).
access by index is provided to sequences (ie: subvalue.things.-1 is the last element of the subvalue.things sequence.)
access to all sequence/structs elements in one go for use in bash loops.
you can output whole subpart of a YAML file as ... YAML, which blend well for further manipulations with shyaml.

More sample and documentation are available on the shyaml github page or the shyaml PyPI page.

The definitive guide to form-based website authentication

A good article about realistic password strength estimation is:

Dropbox Tech Blog » Blog Archive » zxcvbn: realistic password strength estimation

Calculating powers of integers

I managed to modify(boundaries, even check, negative nums check) Qx__ answer. Use at your own risk. 0^-1, 0^-2 etc.. returns 0.

private static int pow(int x, int n) {
        if (n == 0)
            return 1;
        if (n == 1)
            return x;
        if (n < 0) { // always 1^xx = 1 && 2^-1 (=0.5 --> ~ 1 )
            if (x == 1 || (x == 2 && n == -1))
                return 1;
            else
                return 0;
        }
        if ((n & 1) == 0) { //is even 
            long num = pow(x * x, n / 2);
            if (num > Integer.MAX_VALUE) //check bounds
                return Integer.MAX_VALUE; 
            return (int) num;
        } else {
            long num = x * pow(x * x, n / 2);
            if (num > Integer.MAX_VALUE) //check bounds
                return Integer.MAX_VALUE;
            return (int) num;
        }
    }

Where does the .gitignore file belong?

In the simple case, a repository might have a single .gitignore file in its root directory, which applies recursively to the entire repository. However, it is also possible to have additional .gitignore files in subdirectories. The rules in these nested .gitignore files apply only to the files under the directory where they are located. The Linux kernel source repository has 206 .gitignore files.

-- this is what i read from progit.pdf(version 2), P32

Illegal Character when trying to compile java code

If using an IDE, specify the java file encoding (via the properties panel)
If NOT using an IDE, use an advanced text-editor (I can recommend Notepad++) and set the encoding to "UTF without BOM", or "ANSI", if that suits you.

Python not working in the command line of git bash

I don't see next option in a list of answers, but I can get interactive prompt with "-i" key:

$ python -i
Python 3.5.2 (v3.5.2:4def2a2901a5, Jun 25 2016, 22:18:55)
Type "help", "copyright", "credits" or "license" for more information.
>>>

System.Collections.Generic.List does not contain a definition for 'Select'

This question's bit old, but, there's a tricky scenario which also leads to this error:

In controller:

ViewBag.id = //id from querystring
List<string> = GrabDataFromDBByID(ViewBag.id).Select(a=>a.ToString());

The above code will lead to an error in this part: .Select(a=>a.ToString()) because of the below reason: You're passing a ViewBag.id to a method which in compiler, it doesn't know the type, so there might be several methods with the same name and different parameters let's say:

GrabDataFromDBByID(string)
GrabDataFromDBByID(int)
GrabDataFromDBByID(whateverType)

So to prevent this case, either explicitly cast the ViewBag or create another variable storing it.

How can I tell if an algorithm is efficient?

Yes you can start with the Wikipedia article explaining the Big O notation, which in a nutshell is a way of describing the "efficiency" (upper bound of complexity) of different type of algorithms. Or you can look at an earlier answer where this is explained in simple english

RSA encryption and decryption in Python

Watch out using Crypto!!! It is a wonderful library but it has an issue in python3.8 'cause from the library time was removed the attribute clock(). To fix it just modify the source in /usr/lib/python3.8/site-packages/Crypto/Random/_UserFriendlyRNG.pyline 77 changing t = time.clock() int t = time.perf_counter()

Disabling Minimize & Maximize On WinForm?

The Form has two properties called MinimizeBox and MaximizeBox, set both of them to false.

To stop the form closing, handle the FormClosing event, and set e.Cancel = true; in there and after that, set WindowState = FormWindowState.Minimized;, to minimize the form.

Length of a JavaScript object

_x000D_

   let myobject= {}
    let isempty =  !!Object.values(myobject);
    console.log(isempty);

_x000D_

Python: access class property from string

A picture's worth a thousand words:

>>> class c:
        pass
o = c()
>>> setattr(o, "foo", "bar")
>>> o.foo
'bar'
>>> getattr(o, "foo")
'bar'

Adding author name in Eclipse automatically to existing files

Actually in Eclipse Indigo thru Oxygen, you have to go to the Types template Window -> Preferences -> Java -> Code Style -> Code templates -> (in right-hand pane) Comments -> double-click Types and make sure it has the following, which it should have by default:

/**
 * @author ${user}
 *
 * ${tags}
 */

and as far as I can tell, there is nothing in Eclipse to add the javadoc automatically to existing files in one batch. You could easily do it from the command line with sed & awk but that's another question.

If you are prepared to open each file individually, then selected the class / interface declaration line, e.g. public class AdamsClass { and then hit the key combo Shift + Alt + J and that will insert a new javadoc comment above, along with the author tag for your user. To experiment with other settings, go to Windows->Preferences->Java->Editor->Templates.

How to use new PasswordEncoder from Spring Security

I had a similar issue. I needed to keep the legacy encrypted passwords (Base64/SHA-1/Random salt Encoded) as users will not want to change their passwords or re-register. However I wanted to use the BCrypt encoder moving forward too.

My solution was to write a bespoke decoder that checks to see which encryption method was used first before matching (BCrypted ones start with $).

To get around the salt issue, I pass into the decoder a concatenated String of salt + encrypted password via my modified user object.

Decoder

@Component
public class LegacyEncoder implements PasswordEncoder {

    private static final String BCRYP_TYPE = "$";
    private static final PasswordEncoder BCRYPT = new BCryptPasswordEncoder();

    @Override
    public String encode(CharSequence rawPassword) {

    return BCRYPT.encode(rawPassword);
    }

    @Override
    public boolean matches(CharSequence rawPassword, String encodedPassword) {

    if (encodedPassword.startsWith(BCRYP_TYPE)) {
        return BCRYPT.matches(rawPassword, encodedPassword);
    }

    return sha1SaltMatch(rawPassword, encodedPassword);
    }

    @SneakyThrows
    private boolean sha1SaltMatch(CharSequence rawPassword, String encodedPassword) {

    String[] saltHash = encodedPassword.split(User.SPLIT_CHAR);

    // Legacy code from old system   
    byte[] b64salt = Base64.getDecoder().decode(saltHash[0].getBytes());
    byte[] validHash = Base64.getDecoder().decode(saltHash[1]);
    byte[] checkHash = Utility.getHash(5, rawPassword.toString(), b64salt);

    return Arrays.equals(checkHash, validHash);
    }

}

User Object

public class User implements UserDetails {

    public static final String SPLIT_CHAR = ":";

    @Id
    @Column(name = "user_id", nullable = false)
    private Integer userId;

    @Column(nullable = false, length = 60)
    private String password;

    @Column(nullable = true, length = 32)
    private String salt;

.
.

    @PostLoad
    private void init() {

    username = emailAddress; //To comply with UserDetails
    password = salt == null ? password : salt + SPLIT_CHAR + password;
    }

You can also add a hook to re-encode the password in the new BCrypt format and replace it. Thus phasing out the old method.

Use jQuery to hide a DIV when the user clicks outside of it

<!DOCTYPE html>
<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js">
</script>
<script>
$(document).ready(function(){
  $("#hide").click(function(){
    $("p").hide();
  });
  $("#show").click(function(){
    $("p").show();
  });
});
</script>
</head>
<body>
<p>If you click on the "Hide" button, I will disappear.</p>
<button id="hide">Hide</button>
<button id="show">Show</button>
</body>
</html>

New line character in VB.Net?

you can solve that problem in visual basic .net without concatenating your text, you can use this as a return type of your overloaded Tostring:

System.Text.RegularExpressions.Regex.Unescape(String.format("FirstName:{0} \r\n LastName: {1}", "Nordanne", "Isahac"))

How do you convert a jQuery object into a string?

No need to clone and add to the DOM to use .html(), you can do:

$('#item-of-interest').wrap('<div></div>').html()

How can I check which version of Angular I'm using?

For angular JS you can find it on angular-animate.js file as below:

How to get longitude and latitude of any address?

You can use the Google Maps API for that. See the blog post below for more information.

http://stuff.nekhbet.ro/2008/12/12/how-to-get-coordinates-for-a-given-address-using-php.html

How to move mouse cursor using C#?

First Add a Class called Win32.cs

public class Win32
{ 
    [DllImport("User32.Dll")]
    public static extern long SetCursorPos(int x, int y);

    [DllImport("User32.Dll")]
    public static extern bool ClientToScreen(IntPtr hWnd, ref POINT point);

    [StructLayout(LayoutKind.Sequential)]
    public struct POINT
    {
        public int x;
        public int y;

        public POINT(int X, int Y)
        {
            x = X;
            y = Y;
        }
    }
}

You can use it then like this:

Win32.POINT p = new Win32.POINT(xPos, yPos);

Win32.ClientToScreen(this.Handle, ref p);
Win32.SetCursorPos(p.x, p.y);

How to remove the default arrow icon from a dropdown list (select element)?

there's a library called DropKick.js that replaces the normal select dropdowns with HTML/CSS so you can fully style and control them with javascript. http://dropkickjs.com/

Click toggle with jQuery

<label>
    <input
        type="checkbox"
        onclick="$('input[type=checkbox]').attr('checked', $(this).is(':checked'));"
    />
    Check all
</label>

What is the error "Every derived table must have its own alias" in MySQL?

Every derived table (AKA sub-query) must indeed have an alias. I.e. each query in brackets must be given an alias (AS whatever), which can the be used to refer to it in the rest of the outer query.

SELECT ID FROM (
    SELECT ID, msisdn FROM (
        SELECT * FROM TT2
    ) AS T
) AS T

In your case, of course, the entire query could be replaced with:

SELECT ID FROM TT2

Programs & Examples On #Firebird embedded

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jQuery click / toggle between two functions

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what's the differences between r and rb in fopen

Parse an URL in JavaScript

Maven build debug in Eclipse

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Convert a PHP object to an associative array

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Setting Camera Parameters in OpenCV/Python

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Show whitespace characters in Visual Studio Code

UILabel is not auto-shrinking text to fit label size

nginx 502 bad gateway

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Programmatically shut down Spring Boot application

Select first row in each GROUP BY group?

How does the "view" method work in PyTorch?

torch.Tensor.view()

torch.reshape()

fetch from origin with deleted remote branches?

How to return a boolean method in java?

Source file not compiled Dev C++

How to post ASP.NET MVC Ajax form using JavaScript rather than submit button

CSS background opacity with rgba not working in IE 8

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Margin-Top not working for span element?

TortoiseSVN icons not showing up under Windows 7

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Maven build Compilation error : Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project Maven

mongodb count num of distinct values per field/key

geom_smooth() what are the methods available?

How do I concatenate a string with a variable?

How to change JDK version for an Eclipse project

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How can I reverse a list in Python?

connecting to mysql server on another PC in LAN

Spark RDD to DataFrame python

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CSS: fixed position on x-axis but not y?

Python Inverse of a Matrix

How to print out a variable in makefile

Running powershell script within python script, how to make python print the powershell output while it is running

How to run an EXE file in PowerShell with parameters with spaces and quotes

What is SaaS, PaaS and IaaS? With examples

How do I Validate the File Type of a File Upload?

Using Postman to access OAuth 2.0 Google APIs

How to drop all stored procedures at once in SQL Server database?

How to count lines of Java code using IntelliJ IDEA?

Browser Caching of CSS files

Array String Declaration

Access to build environment variables from a groovy script in a Jenkins build step (Windows)

Make: how to continue after a command fails?

Android set bitmap to Imageview

Passing route control with optional parameter after root in express?

How to use nanosleep() in C? What are `tim.tv_sec` and `tim.tv_nsec`?

HTML5 iFrame Seamless Attribute

How to join two tables by multiple columns in SQL?

How do you grep a file and get the next 5 lines

Trying to get PyCharm to work, keep getting "No Python interpreter selected"

Checking if output of a command contains a certain string in a shell script

AngularJS - Value attribute on an input text box is ignored when there is a ng-model used?

The Angular way

If however, you don't have time to start over from scratch

Using a directive

how to insert datetime into the SQL Database table?

How do I parse a HTML page with Node.js

How to extract a single value from JSON response?

Remove all special characters from a string

Convert Python program to C/C++ code?

AngularJS - add HTML element to dom in directive without jQuery

Avoid Adding duplicate elements to a List C#

`torch.Tensor.view()`