ValueError: could not convert string to float: id

I solved the similar situation with basic technique using pandas. First load the csv or text file using pandas.It's pretty simple

data=pd.read_excel('link to the file')

Then set the index of data to the respected column that needs to be changed. For example, if your data has ID as one attribute or column, then set index to ID.

 data = data.set_index("ID")

Then delete all the rows with "id" as the value instead of number using following command.

  data = data.drop("id", axis=0).

Hope, this will help you.

Why cannot cast Integer to String in java?

Why this is not possible:

Because String and Integer are not in the same Object hierarchy.

      Object
     /      \
    /        \
String     Integer

The casting which you are trying, works only if they are in the same hierarchy, e.g.

      Object
     /
    /
   A
  /
 /
B

In this case, (A) objB or (Object) objB or (Object) objA will work.

Hence as others have mentioned already, to convert an integer to string use:

String.valueOf(integer), or Integer.toString(integer) for primitive,

Integer.toString() for the object.

How to check if a registry value exists using C#?

Of course, "Fagner Antunes Dornelles" is correct in its answer. But it seems to me that it is worth checking the registry branch itself in addition, or be sure of the part that is exactly there.

For example ("dirty hack"), i need to establish trust in the RMS infrastructure, otherwise when i open Word or Excel documents, i will be prompted for "Active Directory Rights Management Services". Here's how i can add remote trust to me servers in the enterprise infrastructure.

foreach (var strServer in listServer)
{
    try
    {
        RegistryKey regCurrentUser = Registry.CurrentUser.OpenSubKey($"Software\\Classes\\Local Settings\\Software\\Microsoft\\MSIPC\\{strServer}", false);
        if (regCurrentUser == null)
            throw new ApplicationException("Not found registry SubKey ...");
        if (regCurrentUser.GetValueNames().Contains("UserConsent") == false)
            throw new ApplicationException("Not found value in SubKey ...");
    }
    catch (ApplicationException appEx)
    {
        Console.WriteLine(appEx);
        try
        {
            RegistryKey regCurrentUser = Registry.CurrentUser.OpenSubKey($"Software\\Classes\\Local Settings\\Software\\Microsoft\\MSIPC", true);
            RegistryKey newKey = regCurrentUser.CreateSubKey(strServer, true);
            newKey.SetValue("UserConsent", 1, RegistryValueKind.DWord);
        }
        catch(Exception ex)
        {
            Console.WriteLine($"{ex} Pipec kakoito ...");
        }
    }
}

Php $_POST method to get textarea value

Try this:

<?php /* the php */ ?>
<?php 
    if ($_POST['submit']) {
        // must work
        echo $_POST['contact_list'];
    };
?>


 <?php /* and the html */ ?>

<!doctype html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>teszt</title>
    </head>
    <body>
        <form method="post" action="<?php echo $_SERVER['PHP_SELF'] ?>">
            <textarea id="contact_list" name="contact_list"></textarea>
            <input type="submit" name="submit" value="Send" id="submit"/>
        </form>
    </body>
</html>

How do I set a variable to the output of a command in Bash?

You can use backticks (also known as accent graves) or $().

Like:

OUTPUT=$(x+2);
OUTPUT=`x+2`;

Both have the same effect. But OUTPUT=$(x+2) is more readable and the latest one.

How to Delete Session Cookie?

There are known issues with IE and Opera not removing session cookies when setting the expire date to the past (which is what the jQuery cookie plugin does)

This works fine in Safari and Mozilla/FireFox.

how to convert a string to an array in php

explode() might be the function you are looking for

$array = explode(' ',$str);

Is there a way to get version from package.json in nodejs code?

Option 1

Best practice is to version from package.json using npm environment variables.

process.env.npm_package_version

more information on: https://docs.npmjs.com/using-npm/config.html

This will work only when you start your service using NPM command.

Quick Info: you can read any values in pacakge.json using process.env.npm_package_[keyname]

Option 2

Setting version in environment variable using https://www.npmjs.com/package/dotenv as .env file and reading it as process.env.version

How to solve Permission denied (publickey) error when using Git?

I met the same issue because of I was thought the difference between SSH and HTTPS is

https://github.com/USERNAME/REPOSITORY.git

ssh://github.com/USERNAME/REPOSITORY.git

So I changed from HTTPS to SSH just by changing https:// to ssh:// nothing on the end of the url was changed.

But the truth is:

https://github.com/USERNAME/REPOSITORY.git

[email protected]:USERNAME/REPOSITORY.git

Which means I changed ssh://github.com/USERNAME/REPOSITORY.git to [email protected]:USERNAME/REPOSITORY.git it works.

Stupid error but hope helps someone!

How to use timeit module

This works great:

  python -m timeit -c "$(cat file_name.py)"

How to change font size in html?

Give them a class and add your style to the class.

<style>
  p {
    color: red;
  }
  .paragraph1 {
    font-size: 18px;
  }
  .paragraph2 {
    font-size: 13px;
  }
</style>

<p class="paragraph1">Paragraph 1</p>
<p class="paragraph2">Paragraph 2</p>

Check this EXAMPLE

Aren't Python strings immutable? Then why does a + " " + b work?

Python strings are immutable. However, a is not a string: it is a variable with a string value. You can't mutate the string, but can change what value of the variable to a new string.

How can I render a list select box (dropdown) with bootstrap?

Another way without using the .form-control is this:

  $(".dropdown-menu li a").click(function(){
        $(this).parents(".btn-group").find('.btn').html($(this).text() + ' <span class="caret"></span>');
        $(this).parents(".btn-group").find('.btn').val($(this).data('value'));
      });

_x000D_

$(".dropdown-menu li a").click(function(){_x000D_
  $(this).parents(".btn-group").find('.btn').html($(this).text() + ' <span class="caret"></span>');_x000D_
  $(this).parents(".btn-group").find('.btn').val($(this).data('value'));_x000D_
});

_x000D_

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>_x000D_
_x000D_
<link href="http://netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
<script src="http://netdna.bootstrapcdn.com/bootstrap/3.0.0/js/bootstrap.min.js"></script>_x000D_
_x000D_
_x000D_
<div class="btn-group">_x000D_
  <button  type="button" class="btn btn-info dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">_x000D_
                  Test <span class="caret"> </span>_x000D_
  </button>_x000D_
  <ul class="dropdown-menu">_x000D_
    <li><a href='#'>test 1</a></li>_x000D_
    <li><a href='#'>test 2</a></li>_x000D_
    <li><a href='#'>test 3</a></li>_x000D_
  </ul>_x000D_
</div>

_x000D_

Numpy ValueError: setting an array element with a sequence. This message may appear without the existing of a sequence?

Z=np.array([1.0,1.0,1.0,1.0])  

def func(TempLake,Z):
    A=TempLake
    B=Z
    return A*B
Nlayers=Z.size
N=3
TempLake=np.zeros((N+1,Nlayers))
kOUT=np.vectorize(func)(TempLake,Z)

This works too , instead of looping , just vectorize however read below notes from the scipy documentation : https://docs.scipy.org/doc/numpy/reference/generated/numpy.vectorize.html

The vectorize function is provided primarily for convenience, not for performance. The implementation is essentially a for loop.

If otypes is not specified, then a call to the function with the first argument will be used to determine the number of outputs. The results of this call will be cached if cache is True to prevent calling the function twice. However, to implement the cache, the original function must be wrapped which will slow down subsequent calls, so only do this if your function is expensive.

How to paste yanked text into the Vim command line

I was having a similar problem. I wanted the selected text to end up in a command, but not rely on pasting it in. Here's the command I was trying to write a mapping for:

:call VimuxRunCommand("python")

The docs for this plugin only show using string literals. The following will break if you try to select text that contains doublequotes:

vnoremap y:call VimuxRunCommand("<c-r>"")<cr>

To get around this, you just reference the contents of the macro using @ :

vnoremap y:call VimuxRunCommand(@")<cr>

Passes the contents of the unnamed register in and works with my double quote and multiline edgecases.

"Could not find bundler" error

I got this after upgrading to ruby 2.1.0. My PATH was set in my login script to include .gem/ruby/2.0.0/bin. Updating the version number fixed it.

Error: No default engine was specified and no extension was provided

If you wish to render a html file, use:

response.sendfile('index.html');

Then you remove:

app.set('view engine', 'html');

Put your *.html in the views directory, or serve a public directory as static dir and put the index.html in the public dir.

Bootstrap select dropdown list placeholder

I think, the Dropdown box with a class and JQuery code to disable the first option for user to select, will work perfectly as Select Box placeholder.

<select class="selectboxclass">
   <option value="">- Please Select -</option>
   <option value="IN">India</option>
   <option value="US">America</option>
</select>

Make the first option disabled by JQuery.

<script>
$('select.selectboxclass option:first').attr('disabled', true);
</script>

This will make the first option of Dropdown as Placeholder and user will no longer able to select the first option.

Hope It helps!!

How do I delete all the duplicate records in a MySQL table without temp tables

Instead of drop table TableA, you could delete all registers (delete from TableA;) and then populate original table with registers coming from TableA_Verify (insert into TAbleA select * from TAbleA_Verify). In this way you won't lost all references to original table (indexes,... )

CREATE TABLE TableA_Verify AS SELECT DISTINCT * FROM TableA;

DELETE FROM TableA;

INSERT INTO TableA SELECT * FROM TAbleA_Verify;

DROP TABLE TableA_Verify;

How to use a BackgroundWorker?

I know this is a bit old, but in case another beginner is going through this, I'll share some code that covers a bit more of the basic operations, here is another example that also includes the option to cancel the process and also report to the user the status of the process. I'm going to add on top of the code given by Alex Aza in the solution above

public Form1()
{
    InitializeComponent();

    backgroundWorker1.DoWork += backgroundWorker1_DoWork;
    backgroundWorker1.ProgressChanged += backgroundWorker1_ProgressChanged;
    backgroundWorker1.RunWorkerCompleted += backgroundWorker1_RunWorkerCompleted;  //Tell the user how the process went
    backgroundWorker1.WorkerReportsProgress = true;
    backgroundWorker1.WorkerSupportsCancellation = true; //Allow for the process to be cancelled
}

//Start Process
private void button1_Click(object sender, EventArgs e)
{
    backgroundWorker1.RunWorkerAsync();
}

//Cancel Process
private void button2_Click(object sender, EventArgs e)
{
    //Check if background worker is doing anything and send a cancellation if it is
    if (backgroundWorker1.IsBusy)
    {
        backgroundWorker1.CancelAsync();
    }

}

private void backgroundWorker1_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)
{
    for (int i = 0; i < 100; i++)
    {
        Thread.Sleep(1000);
        backgroundWorker1.ReportProgress(i);

        //Check if there is a request to cancel the process
        if (backgroundWorker1.CancellationPending)
        {
            e.Cancel = true;
            backgroundWorker1.ReportProgress(0);
            return;
        }
    }
    //If the process exits the loop, ensure that progress is set to 100%
    //Remember in the loop we set i < 100 so in theory the process will complete at 99%
    backgroundWorker1.ReportProgress(100);
}

private void backgroundWorker1_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)
{
    progressBar1.Value = e.ProgressPercentage;
}

private void backgroundWorker1_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)
{
    if (e.Cancelled)
    {
         lblStatus.Text = "Process was cancelled";
    }
    else if (e.Error != null)
    {
         lblStatus.Text = "There was an error running the process. The thread aborted";
    }
    else
    {
       lblStatus.Text = "Process was completed";
    }
}

CodeIgniter: Create new helper?

Well for me only works adding the text "_helper" after in the php file like:

Codeiginiter Helpers

And to load automatically the helper in the folder aplication -> file autoload.php add in the array helper's the name without "_helper" like:

$autoload['helper'] = array('comunes');

And with that I can use all the helper's functions

Cannot assign requested address - possible causes?

Maybe SO_REUSEADDR helps here? http://www.unixguide.net/network/socketfaq/4.5.shtml

What is python's site-packages directory?

site-packages is the target directory of manually built Python packages. When you build and install Python packages from source (using distutils, probably by executing python setup.py install), you will find the installed modules in site-packages by default.

There are standard locations:

Unix (pure)¹: prefix/lib/pythonX.Y/site-packages
Unix (non-pure): exec-prefix/lib/pythonX.Y/site-packages
Windows: prefix\Lib\site-packages

¹ Pure means that the module uses only Python code. Non-pure can contain C/C++ code as well.

site-packages is by default part of the Python search path, so modules installed there can be imported easily afterwards.

Useful reading

Installing Python Modules (for Python 2)
Installing Python Modules (for Python 3)

How to delete rows from a pandas DataFrame based on a conditional expression

To directly answer this question's original title "How to delete rows from a pandas DataFrame based on a conditional expression" (which I understand is not necessarily the OP's problem but could help other users coming across this question) one way to do this is to use the drop method:

df = df.drop(some labels)
df = df.drop(df[<some boolean condition>].index)

Example

To remove all rows where column 'score' is < 50:

df = df.drop(df[df.score < 50].index)

In place version (as pointed out in comments)

df.drop(df[df.score < 50].index, inplace=True)

Multiple conditions

(see Boolean Indexing)

The operators are: | for or, & for and, and ~ for not. These must be grouped by using parentheses.

To remove all rows where column 'score' is < 50 and > 20

df = df.drop(df[(df.score < 50) & (df.score > 20)].index)

How do I use updatePanel in asp.net without refreshing all page?

Please refer below Ajax overview:

http://msdn.microsoft.com/en-us/library/bb386454.aspx

Converting string into datetime

Create a small utility function like:

def date(datestr="", format="%Y-%m-%d"):
    from datetime import datetime
    if not datestr:
        return datetime.today().date()
    return datetime.strptime(datestr, format).date()

This is versatile enough:

If you don't pass any arguments it will return today's date.
There's a date format as default that you can override.
You can easily modify it to return a datetime.

How to pass the id of an element that triggers an `onclick` event to the event handling function

The element that triggered the event can be different than the one you bound the handler to because events bubble up the DOM tree.

So if you want to get the ID of the element the event handler is bound to, you can do this easily with this.id (this refers to the element).

But if you want to get the element where the event originated, then you have to access it with event.target in W3C compatible browsers and event.srcElement in IE 8 and below.

I would avoid writing a lot of JavaScript in the onXXXX HTML attributes. I would only pass the event object and put the code to extract the element in the handler (or in an extra function):

<div onlick="doWithThisElement(event)">

Then the handler would look like this:

function doWithThisElement(event) {
    event = event || window.event; // IE
    var target = event.target || event.srcElement; // IE

    var id = target.id;
    //...
}

I suggest to read the excellent articles about event handling at quirksmode.org.

Btw

<link onclick="doWithThisElement(id_of_this_element)" />

does hardly make sense (<link> is an element that can only appear in the <head>, binding an event handler (if even possible) will have no effect).

HTML form readonly SELECT tag/input

html solution:

<select onfocus="this.blur();">

javascript ones:

selectElement.addEventListener("focus", selectElement.blur, true); selectElement.attachEvent("focus", selectElement.blur); //thanks, IE

to remove:

selectElement.removeEventListener("focus", selectElement.blur, true); selectElement.detachEvent("focus", selectElement.blur); //thanks, IE

edit: added remove methods

div with dynamic min-height based on browser window height

Just look for my solution on jsfiddle, it is based on csslayout

_x000D_

html,_x000D_
body {_x000D_
  margin: 0;_x000D_
  padding: 0;_x000D_
  height: 100%; /* needed for container min-height */_x000D_
}_x000D_
div#container {_x000D_
  position: relative; /* needed for footer positioning*/_x000D_
  height: auto !important; /* real browsers */_x000D_
  min-height: 100%; /* real browsers */_x000D_
}_x000D_
div#header {_x000D_
  padding: 1em;_x000D_
  background: #efe;_x000D_
}_x000D_
div#content {_x000D_
  /* padding:1em 1em 5em; *//* bottom padding for footer */_x000D_
}_x000D_
div#footer {_x000D_
  position: absolute;_x000D_
  width: 100%;_x000D_
  bottom: 0; /* stick to bottom */_x000D_
  background: #ddd;_x000D_
}

_x000D_

<div id="container">_x000D_
_x000D_
  <div id="header">header</div>_x000D_
_x000D_
  <div id="content">_x000D_
    content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>_x000D_
  </div>_x000D_
_x000D_
  <div id="footer">_x000D_
    footer_x000D_
  </div>_x000D_
</div>

_x000D_

Checking if an object is a given type in Swift

If you just want to check the class without getting a warning because of the unused defined value (let someVariable ...), you can simply replace the let stuff with a boolean:

if (yourObject as? ClassToCompareWith) != nil {
   // do what you have to do
}
else {
   // do something else
}

Xcode proposed this when I used the let way and didn't use the defined value.

Getting multiple keys of specified value of a generic Dictionary?

The "simple" bidirectional dictionary solution proposed here is complex and may be be difficult to understand, maintain or extend. Also the original question asked for "the key for a value", but clearly there could be multiple keys (I've since edited the question). The whole approach is rather suspicious.

Software changes. Writing code that is easy to maintain should be given priority other "clever" complex workarounds. The way to get keys back from values in a dictionary is to loop. A dictionary isn't designed to be bidirectional.

I have 2 dates in PHP, how can I run a foreach loop to go through all of those days?

<?php

    $start_date = '2015-01-01';
    $end_date = '2015-06-30';

    while (strtotime($start_date) <= strtotime($end_date)) {
        echo "$start_daten";
        $start_date = date ("Y-m-d", strtotime("+1 days", strtotime($start_date)));
    }

?>

[INSTALL_FAILED_NO_MATCHING_ABIS: Failed to extract native libraries, res=-113]

This is caused by a gradle dependency on some out-of-date thing which causes the error. Remove gradle dependencies until the error stops appearing. For me, it was:

implementation 'org.apache.directory.studio:org.apache.commons.io:2.4'

This line needed to be updated to a newer version such as:

api group: 'commons-io', name: 'commons-io', version: '2.6'

What datatype to use when storing latitude and longitude data in SQL databases?

I think it depends on the operations you'll be needing to do most frequently.

If you need the full value as a decimal number, then use decimal with appropriate precision and scale. Float is way beyond your needs, I believe.

If you'll be converting to/from degºmin'sec"fraction notation often, I'd consider storing each value as an integer type (smallint, tinyint, tinyint, smallint?).

Using Pipes within ngModel on INPUT Elements in Angular

You can't use Template expression operators(pipe, save navigator) within template statement:

(ngModelChange)="Template statements"

~~(ngModelChange)="item.value | useMyPipeToFormatThatValue=$event"~~

https://angular.io/guide/template-syntax#template-statements

Like template expressions, template statements use a language that looks like JavaScript. The template statement parser differs from the template expression parser and specifically supports both basic assignment (=) and chaining expressions (with ; or ,).

However, certain JavaScript syntax is not allowed:

new

increment and decrement operators, ++ and --

operator assignment, such as += and -=

the bitwise operators | and &

the template expression operators

So you should write it as follows:

<input [ngModel]="item.value | useMyPipeToFormatThatValue" 
      (ngModelChange)="item.value=$event" name="inputField" type="text" />

Plunker Example

How to get file path in iPhone app

Remember that the "folders/groups" you make in xcode, those which are yellowish are not reflected as real folders in your iPhone app. They are just there to structure your XCode project. You can nest as many yellow group as you want and they still only serve the purpose of organizing code in XCode.

EDIT

Make a folder outside of XCode then drag it over, and select "Create folder references for any added folders" instead of "Create groups for any added folders" in the popup.

How to get milliseconds from LocalDateTime in Java 8

To avoid ZoneId you can do:

LocalDateTime date = LocalDateTime.of(1970, 1, 1, 0, 0);

System.out.println("Initial Epoch (TimeInMillis): " + date.toInstant(ZoneOffset.ofTotalSeconds(0)).toEpochMilli());

Getting 0 as value, that's right!

How to close a window using jQuery

For IE: window.close(); and self.close(); should work fine.

If you want just open the IE browser and type

javascript:self.close() and hit enter, it should ask you for a prompt.

Note: this method doesn't work for Chrome or Firefox.

Removing a model in rails (reverse of "rails g model Title...")

To remove migration (if you already migrated the migration)

rake db:migrate:down VERSION="20130417185845" #Your migration version

To remove Model

rails d model name  #name => Your model name

typedef fixed length array

You want

typedef char type24[3];

C type declarations are strange that way. You put the type exactly where the variable name would go if you were declaring a variable of that type.

Pentaho Data Integration SQL connection

I just came across the same issue while trying to query a MySQL Database from Pentaho.

Error connecting to database [Local MySQL DB] : org.pentaho.di.core.exception.KettleDatabaseException: Error occured while trying to connect to the database

Exception while loading class org.gjt.mm.mysql.Driver

Expanding post by @user979331 the solution is:

Download the MySQL Java Connector / Driver that is compatible with your kettle version
Unzip the zip file (in my case it was mysql-connector-java-5.1.31.zip)
copy the .jar file (mysql-connector-java-5.1.31-bin.jar) and paste it in your Lib folder:

PC: C:\Program Files\pentaho\design-tools\data-integration\lib

Mac: /Applications/data-integration/lib

Restart Pentaho (Data Integration) and re-test the MySQL Connection.

Additional interesting replies from others that could also help:

think to download the good JDBC driver version, compatible with your PDI version: https://help.pentaho.com/Documentation/8.1/Setup/JDBC_Drivers_Reference#MY_SQL
take the zip version ("platform independant") to extract the jar file
take into lib folder
see also proper way to handle it proposed by Ryan Tuck

DD/MM/YYYY Date format in Moment.js

You can use this

moment().format("DD/MM/YYYY");

However, this returns a date string in the specified format for today, not a moment date object. Doing the following will make it a moment date object in the format you want.

var someDateString = moment().format("DD/MM/YYYY");
var someDate = moment(someDateString, "DD/MM/YYYY");

Update Git branches from master

to update your branch from the master:

  git checkout master
  git pull
  git checkout your_branch
  git merge master

iOS9 getting error “an SSL error has occurred and a secure connection to the server cannot be made”

The problem is the ssl certificate on server side. Either something is interfering or the certificate doesn't match the service. For instance when a site has a ssl cert for www.mydomain.com while the service you use runs on myservice.mydomain.com. That is a different machine.

How to run a cronjob every X minutes?

You are setting your cron to run on 10th minute in every hour.
To set it to every 5 mins change to */5 * * * * /usr/bin/php /mydomain.in/cronmail.php > /dev/null 2>&1

How to add a new project to Github using VS Code

Install git on your PC and setup configuration values in either Command Prompt (cmd) or VS Code terminal (Ctrl + `)

git config --global user.name "Your Name"
git config --global user.email [email protected]

Setup editor

Windows eg.:

git config --global core.editor "'C:/Program Files/Notepad++/notepad++.exe' -multiInst -nosession"

Linux / Mac eg.:

git config --global core.editor vim

Check git settings which displays configuration details

git config --list

Navigate to your project directory and execute the below commands

git init                                                           // start tracking current directory
git add -A                                                         // add all files in current directory to staging area, making them available for commit
git commit -m "commit message"                                     // commit your changes
git remote add origin https://github.com/username/repo-name.git    // add remote repository URL which contains the required details
git pull origin master                                             // always pull from remote before pushing
git push -u origin master                                          // publish changes to your remote repository

Convert Enumeration to a Set/List

When using guava (See doc) there is Iterators.forEnumeration. Given an Enumeration x you can do the following:

to get a immutable Set:

ImmutableSet.copyOf(Iterators.forEnumeration(x));

to get a immutable List:

ImmutableList.copyOf(Iterators.forEnumeration(x));

to get a hashSet:

Sets.newHashSet(Iterators.forEnumeration(x));

PHP Session Destroy on Log Out Button

// logout

if(isset($_GET['logout'])) {
    session_destroy();
    unset($_SESSION['username']);
    header('location:login.php');
}

How to listen state changes in react.js?

It's been a while but for future reference: the method shouldComponentUpdate() can be used.

An update can be caused by changes to props or state. These methods are called in the following order when a component is being re-rendered:

static getDerivedStateFromProps() 
shouldComponentUpdate() 
render()
getSnapshotBeforeUpdate() 
componentDidUpdate()

ref: https://reactjs.org/docs/react-component.html

Syntax error near unexpected token 'fi'

"Then" is a command in bash, thus it needs a ";" or a newline before it.

#!/bin/bash
echo "start\n"
for f in *.jpg
do
  fname=$(basename "$f")
  echo "fname is $fname\n"
  fname="${filename%.*}"
  echo "fname is $fname\n"
  if [$[fname%2] -eq 1 ]
  then
    echo "removing $fname\n"
    rm $f
  fi
done

How to get list of all installed packages along with version in composer?

You can run composer show -i (short for --installed).

In the latest version just use composer show.

The -i options has been deprecated.

You can also use the global instalation of composer: composer global show

How to get the previous URL in JavaScript?

Those of you using Node.js and Express can set a session cookie that will remember the current page URL, thus allowing you to check the referrer on the next page load. Here's an example that uses the express-session middleware:

//Add me after the express-session middleware    
app.use((req, res, next) => {
    req.session.referrer = req.protocol + '://' + req.get('host') + req.originalUrl;
    next();
});

You can then check for the existance of a referrer cookie like so:

if ( req.session.referrer ) console.log(req.session.referrer);

Do not assume that a referrer cookie always exists with this method as it will not be available on instances where the previous URL was another website, the session was cleaned or was just created (first-time website load).

TypeError: 'list' object is not callable while trying to access a list

I also got the error when I called a function that had the same name as another variable that was classified as a list.

Once I sorted out the naming the error was resolved.

Install apps silently, with granted INSTALL_PACKAGES permission

Try this LD_LIBRARY_PATH=/vendor/lib:/system/lib before pm install. It works well.

What is the difference between logical data model and conceptual data model?

This is an old question and maybe this comes way too late, but I don't see one very important aspect necessary to answering the question. That is, the TARGET audience for the data model. The Conceptual Data Model is the model generated from business analysis, from interviews with the BUSINESS about their data. It is not so much "high level" as it is the business's understanding of their data, business rules captured in the relationships between "candidate" entities. At this point, you are capturing the things of importance to the business (Employee, Customer, Contract, Account, etc.) and the relationships between them. The final Conceptual Data Model may be somewhat abstract -- for instance, treating Individuals and Organizations entering into a contract as subtypes of a "Party", Contractors and Permanent Employees as subtypes of an Employee, even Employees and Customers subtypes of "Person" -- but it is a document that a data modeler develops from discussions with the business SMEs and presents to the business for validation.

The Logical Data Model is not just "more detail" -- where useful and important, a Conceptual Data Model may well have attributes included -- it is the ARCHITECTURE document, the model that is presented to the software analysts/engineers to explain and specify the data requirements. It will resolve many-to-many relationships to association tables and will define all attributes, with examples and constraints, so that code can be written against the architecture.

The Physical model is that Logical Model generated specifically for a particular environment, such as SQL Server or Teradata or Oracle or whatever. It will have keys, indexes, partitions, or whatever is needed to implement, based on sizing, access frequency, security constraints, etc.

So, if you are being asked to develop a Conceptual Data Model, you are being asked to design the solution (or part of it) from scratch, getting your information from the business. There's more to it, but I hope that answers the question.

All possible array initialization syntaxes

You can also create dynamic arrays i.e. you can first ask the size of the array from the user before creating it.

Console.Write("Enter size of array");
int n = Convert.ToInt16(Console.ReadLine());

int[] dynamicSizedArray= new int[n]; // Here we have created an array of size n
Console.WriteLine("Input Elements");
for(int i=0;i<n;i++)
{
     dynamicSizedArray[i] = Convert.ToInt32(Console.ReadLine());
}

Console.WriteLine("Elements of array are :");
foreach (int i in dynamicSizedArray)
{
    Console.WriteLine(i);
}
Console.ReadKey();

Difference between readFile() and readFileSync()

readFileSync() is synchronous and blocks execution until finished. These return their results as return values. readFile() are asynchronous and return immediately while they function in the background. You pass a callback function which gets called when they finish. let's take an example for non-blocking.

following method read a file as a non-blocking way

var fs = require('fs');
fs.readFile(filename, "utf8", function(err, data) {
        if (err) throw err;
        console.log(data);
});

following is read a file as blocking or synchronous way.

var data = fs.readFileSync(filename);

LOL...If you don't want readFileSync() as blocking way then take reference from the following code. (Native)

var fs = require('fs');
function readFileAsSync(){
    new Promise((resolve, reject)=>{
        fs.readFile(filename, "utf8", function(err, data) {
                if (err) throw err;
                resolve(data);
        });
    });
}

async function callRead(){
    let data = await readFileAsSync();
    console.log(data);
}

callRead();

it's mean behind scenes readFileSync() work same as above(promise) base.

How can I disable the UITableView selection?

You can also do it from the storyboard. Click the table view cell and in the attributes inspector under Table View Cell, change the drop down next to Selection to None.

How to rename array keys in PHP?

foreach ($basearr as &$row)
{
    $row['value'] = $row['url'];
    unset( $row['url'] );
}

unset($row);

How do I run a Java program from the command line on Windows?

It is easy. If you have saved your file as A.text first thing you should do is save it as A.java. Now it is a Java file.

Now you need to open cmd and set path to you A.java file before compile it. you can refer this for that.

Then you can compile your file using command

javac A.java

Then run it using

java A

So that is how you compile and run a java program in cmd. You can also go through these material that is Java in depth lessons. Lot of things you need to understand in Java is covered there for beginners.

Maven: add a folder or jar file into current classpath

The classpath setting of the compiler plugin are two args. Changed it like this and it worked for me:

<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6.1</version>
<configuration>
  <compilerArgs>
     <arg>-cp</arg>
     <arg>${cp}:${basedir}/lib/bad.jar</arg>
  </compilerArgs>
</configuration>

I used the gmavenplus-plugin to read the path and create the property 'cp':

      <plugin>
    <!--
      Use Groovy to read classpath and store into
      file named value of property <cpfile>

      In second step use Groovy to read the contents of
      the file into a new property named <cp>

      In the compiler plugin this is used to create a
      valid classpath
    -->
    <groupId>org.codehaus.gmavenplus</groupId>
    <artifactId>gmavenplus-plugin</artifactId>
    <version>1.12.0</version>
    <dependencies>
      <dependency>
        <groupId>org.codehaus.groovy</groupId>
        <artifactId>groovy-all</artifactId>
        <!-- any version of Groovy \>= 1.5.0 should work here -->
        <version>3.0.6</version>
        <type>pom</type>
        <scope>runtime</scope>
      </dependency>
    </dependencies>
    <executions>
      <execution>
        <id>read-classpath</id>
        <phase>validate</phase>
        <goals>
          <goal>execute</goal>
        </goals>
      </execution>

    </executions>
    <configuration>
      <scripts>
        <script><![CDATA[
                def file = new File(project.properties.cpfile)
                /* create a new property named 'cp'*/
                project.properties.cp = file.getText()
                println '<<< Retrieving classpath into new property named <cp> >>>'
                println 'cp = ' + project.properties.cp
              ]]></script>
      </scripts>
    </configuration>
  </plugin>

Object creation on the stack/heap?

The two forms are the same with one exception: temporarily, the new (Object *) has an undefined value when the creation and assignment are separate. The compiler may combine them back together, since the undefined pointer is not particularly useful. This does not relate to global variables (unless the declaration is global, in which case it's still true for both forms).

Launch Pycharm from command line (terminal)

To open PyCharm from the terminal in Ubuntu 16.04, cd into

{installation home}/bin

which in my case was

/home/nikhil/pycharm-community-2018.1.1/bin/

and then type:

./pycharm.sh

#1273 - Unknown collation: 'utf8mb4_unicode_ci' cPanel

If you have already exported a .sql file, the best thing to do is to Find and Replace the following if you have them in your file:

utf8mb4_0900_ai_ci to utf8_unicode_ci
utf8mb4 to utf8
utf8_unicode_520_ci to utf8_unicode_ci

It will replace utf8mb4_unicode_ci to utf8_unicode_ci. Now you go to your phpMyAdmin cPanel and set the DB collation to utf8_unicode_ci through Operations > Collation.

If you are exporting to a .sql, it's better to change the format on how you're exporting the file. Check out Evster's anwer (it's in the same page as this)

gcc warning" 'will be initialized after'

use -Wno-reorder (man gcc is your friend :) )

Index of duplicates items in a python list

I think I found a simple solution after a lot of irritation :

if elem in string_list:
    counter = 0
    elem_pos = []
    for i in string_list:
        if i == elem:
            elem_pos.append(counter)
        counter = counter + 1
    print(elem_pos)

This prints a list giving you the indexes of a specific element ("elem")

Multipart File Upload Using Spring Rest Template + Spring Web MVC

More based on the feeling, but this is the error you would get if you missed to declare a bean in the context configuration, so try adding

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    <property name="maxUploadSize" value="10000000"/>
</bean>

How to replace NaN value with zero in a huge data frame?

The following should do what you want:

x <- data.frame(X1=sample(c(1:3,NaN), 200, replace=TRUE), X2=sample(c(4:6,NaN), 200, replace=TRUE))
head(x)
x <- replace(x, is.na(x), 0)
head(x)

How can I get a value from a map?

The answer by Steve Jessop explains well, why you can't use std::map::operator[] on a const std::map. Gabe Rainbow's answer suggests a nice alternative. I'd just like to provide some example code on how to use map::at(). So, here is an enhanced example of your function():

void function(const MAP &map, const std::string &findMe) {
    try {
        const std::string& value = map.at(findMe);
        std::cout << "Value of key \"" << findMe.c_str() << "\": " << value.c_str() << std::endl;
        // TODO: Handle the element found.
    }
    catch (const std::out_of_range&) {
        std::cout << "Key \"" << findMe.c_str() << "\" not found" << std::endl;
        // TODO: Deal with the missing element.
    }
}

And here is an example main() function:

int main() {
    MAP valueMap;
    valueMap["string"] = "abc";
    function(valueMap, "string");
    function(valueMap, "strong");
    return 0;
}

Output:

Value of key "string": abc
Key "strong" not found

Code on Ideone

Remove special symbols and extra spaces and replace with underscore using the replace method

Your regular expression [^a-zA-Z0-9]\s/g says match any character that is not a number or letter followed by a space.

Remove the \s and you should get what you are after if you want a _ for every special character.

var newString = str.replace(/[^A-Z0-9]/ig, "_");

That will result in hello_world___hello_universe

If you want it to be single underscores use a + to match multiple

var newString = str.replace(/[^A-Z0-9]+/ig, "_");

That will result in hello_world_hello_universe

How do I show a "Loading . . . please wait" message in Winforms for a long loading form?

You want to look into 'Splash' Screens.

Display another 'Splash' form and wait until the processing is done.

Here is an example on how to do it.

How to play a sound in C#, .NET

To play an Audio file in the Windows form using C# let's check simple example as follows :

1.Go Visual Studio(VS-2008/2010/2012) --> File Menu --> click New Project.

2.In the New Project --> click Windows Forms Application --> Give Name and then click OK.

A new "Windows Forms" project will opens.

3.Drag-and-Drop a Button control from the Toolbox to the Windows Form.

4.Double-click the button to create automatically the default Click event handler, and add the following code.

This code displays the File Open dialog box and passes the results to a method named "playSound" that you will create in the next step.

 OpenFileDialog dialog = new OpenFileDialog();
 dialog.Filter = "Audio Files (.wav)|*.wav";


if(dialog.ShowDialog() == DialogResult.OK)
{
  string path = dialog.FileName;
  playSound(path);
}

5.Add the following method code under the button1_Click event hander.

 private void playSound(string path)
 {
   System.Media.SoundPlayer player = new System.Media.SoundPlayer();
   player.SoundLocation = path;
   player.Load();
   player.Play();
 }

6.Now let's run the application just by Pressing the F5 to run the code.

7.Click the button and select an audio file. After the file loads, the sound will play.

I hope this is useful example to beginners...

How can I convert a Unix timestamp to DateTime and vice versa?

var dt = DateTime.Now; 
var unixTime = ((DateTimeOffset)dt).ToUnixTimeSeconds();

// 1510396991

var dt = DateTimeOffset.FromUnixTimeSeconds(1510396991);

// [11.11.2017 10:43:11 +00:00]

Does IMDB provide an API?

Another legal alternative to get movie info is the Rotten-Tomatoes API (by Fandango).

Rename Files and Directories (Add Prefix)

Thanks to Peter van der Heijden, here's one that'll work for filenames with spaces in them:

for f in * ; do mv -- "$f" "PRE_$f" ; done

("--" is needed to succeed with files that begin with dashes, whose names would otherwise be interpreted as switches for the mv command)

Split a python list into other "sublists" i.e smaller lists

chunks = [data[100*i:100*(i+1)] for i in range(len(data)/100 + 1)]

This is equivalent to the accepted answer. For example, shortening to batches of 10 for readability:

data = range(35)
print [data[x:x+10] for x in xrange(0, len(data), 10)]
print [data[10*i:10*(i+1)] for i in range(len(data)/10 + 1)]

Outputs:

[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [10, 11, 12, 13, 14, 15, 16, 17, 18, 19], [20, 21, 22, 23, 24, 25, 26, 27, 28, 29], [30, 31, 32, 33, 34]]
[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [10, 11, 12, 13, 14, 15, 16, 17, 18, 19], [20, 21, 22, 23, 24, 25, 26, 27, 28, 29], [30, 31, 32, 33, 34]]

Center a position:fixed element

Try using this for horizontal elements that won't center correctly.

width: calc (width: 100% - width whatever else is off centering it)

For example if your side navigation bar is 200px:

width: calc(100% - 200px);

Android Center text on canvas

I create a method to simplify this:

    public static void drawCenterText(String text, RectF rectF, Canvas canvas, Paint paint) {
    Paint.Align align = paint.getTextAlign();
    float x;
    float y;
    //x
    if (align == Paint.Align.LEFT) {
        x = rectF.centerX() - paint.measureText(text) / 2;
    } else if (align == Paint.Align.CENTER) {
        x = rectF.centerX();
    } else {
        x = rectF.centerX() + paint.measureText(text) / 2;
    }
    //y
    metrics = paint.getFontMetrics();
    float acent = Math.abs(metrics.ascent);
    float descent = Math.abs(metrics.descent);
    y = rectF.centerY() + (acent - descent) / 2f;
    canvas.drawText(text, x, y, paint);

    Log.e("ghui", "top:" + metrics.top + ",ascent:" + metrics.ascent
            + ",dscent:" + metrics.descent + ",leading:" + metrics.leading + ",bottom" + metrics.bottom);
}

rectF is the area you want draw the text,That's it. Details

Find element in List<> that contains a value

Enumerable.First returns the element instead of an index. In both cases you will get an exception if no matching element appears in the list (your original code will throw an IndexOutOfBoundsException when you try to get the item at index -1, but First will throw an InvalidOperationException).

MyList.First(item => string.Equals("foo", item.name)).value

Replacing spaces with underscores in JavaScript?

Try .replace(/ /g,"_");

Edit: or .split(' ').join('_') if you have an aversion to REs

Edit: John Resig said:

If you're searching and replacing through a string with a static search and a static replace it's faster to perform the action with .split("match").join("replace") - which seems counter-intuitive but it manages to work that way in most modern browsers. (There are changes going in place to grossly improve the performance of .replace(/match/g, "replace") in the next version of Firefox - so the previous statement won't be the case for long.)

Move the most recent commit(s) to a new branch with Git

Simplest way to do this:

1. Rename master branch to your newbranch (assuming you are on master branch):

git branch -m newbranch

2. Create master branch from the commit that you wish:

git checkout -b master <seven_char_commit_id>

e.g. git checkout -b master a34bc22

React: how to update state.item[1] in state using setState?

To modify deeply nested objects/variables in React's state, typically three methods are used: vanilla JavaScript's Object.assign, immutability-helper and cloneDeep from Lodash.

There are also plenty of other less popular third-party libs to achieve this, but in this answer, I'll cover just these three options. Also, some additional vanilla JavaScript methods exist, like array spreading, (see @mpen's answer for example), but they are not very intuitive, easy to use and capable to handle all state manipulation situations.

As was pointed innumerable times in top voted comments to the answers, whose authors propose a direct mutation of state: just don't do that. This is a ubiquitous React anti-pattern, which will inevitably lead to unwanted consequences. Learn the right way.

Let's compare three widely used methods.

Given this state object structure:

state = {
    outer: {
        inner: 'initial value'
    }
}

You can use the following methods to update the inner-most inner field's value without affecting the rest of the state.

1. Vanilla JavaScript's Object.assign

_x000D_

const App = () => {
  const [outer, setOuter] = React.useState({ inner: 'initial value' })

  React.useEffect(() => {
    console.log('Before the shallow copying:', outer.inner) // initial value
    const newOuter = Object.assign({}, outer, { inner: 'updated value' })
    console.log('After the shallow copy is taken, the value in the state is still:', outer.inner) // initial value
    setOuter(newOuter)
  }, [])

  console.log('In render:', outer.inner)

  return (
    <section>Inner property: <i>{outer.inner}</i></section>
  )
}

ReactDOM.render(
  <App />,
  document.getElementById('react')
)

_x000D_

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.10.2/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.10.2/umd/react-dom.production.min.js"></script>

<main id="react"></main>

_x000D_

Keep in mind, that Object.assign will not perform a deep cloning, since it only copies property values, and that's why what it does is called a shallow copying (see comments).

For this to work, we should only manipulate the properties of primitive types (outer.inner), that is strings, numbers, booleans.

In this example, we're creating a new constant (const newOuter...), using Object.assign, which creates an empty object ({}), copies outer object ({ inner: 'initial value' }) into it and then copies a different object { inner: 'updated value' } over it.

This way, in the end the newly created newOuter constant will hold a value of { inner: 'updated value' } since the inner property got overridden. This newOuter is a brand new object, which is not linked to the object in state, so it can be mutated as needed and the state will stay the same and not changed until the command to update it is ran.

The last part is to use setOuter() setter to replace the original outer in the state with a newly created newOuter object (only the value will change, the property name outer will not).

Now imagine we have a more deep state like state = { outer: { inner: { innerMost: 'initial value' } } }. We could try to create the newOuter object and populate it with the outer contents from the state, but Object.assign will not be able to copy innerMost's value to this newly created newOuter object since innerMost is nested too deeply.

You could still copy inner, like in the example above, but since it's now an object and not a primitive, the reference from newOuter.inner will be copied to the outer.inner instead, which means that we will end up with local newOuter object directly tied to the object in the state.

That means that in this case mutations of the locally created newOuter.inner will directly affect the outer.inner object (in state), since they are in fact became the same thing (in computer's memory).

Object.assign therefore will only work if you have a relatively simple one level deep state structure with innermost members holding values of the primitive type.

If you have deeper objects (2nd level or more), which you should update, don't use Object.assign. You risk mutating state directly.

2. Lodash's cloneDeep

_x000D_

const App = () => {
  const [outer, setOuter] = React.useState({ inner: 'initial value' })

  React.useEffect(() => {
    console.log('Before the deep cloning:', outer.inner) // initial value
    const newOuter = _.cloneDeep(outer) // cloneDeep() is coming from the Lodash lib
    newOuter.inner = 'updated value'
    console.log('After the deeply cloned object is modified, the value in the state is still:', outer.inner) // initial value
    setOuter(newOuter)
  }, [])

  console.log('In render:', outer.inner)

  return (
    <section>Inner property: <i>{outer.inner}</i></section>
  )
}

ReactDOM.render(
  <App />,
  document.getElementById('react')
)

_x000D_

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.10.2/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.10.2/umd/react-dom.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.min.js"></script>

<main id="react"></main>

_x000D_

Lodash's cloneDeep is way more simple to use. It performs a deep cloning, so it is a robust option, if you have a fairly complex state with multi-level objects or arrays inside. Just cloneDeep() the top-level state property, mutate the cloned part in whatever way you please, and setOuter() it back to the state.

3. immutability-helper

_x000D_

const App = () => {
  const [outer, setOuter] = React.useState({ inner: 'initial value' })
  
  React.useEffect(() => {
    const update = immutabilityHelper
    console.log('Before the deep cloning and updating:', outer.inner) // initial value
    const newOuter = update(outer, { inner: { $set: 'updated value' } })
    console.log('After the cloning and updating, the value in the state is still:', outer.inner) // initial value
    setOuter(newOuter)
  }, [])

  console.log('In render:', outer.inner)

  return (
    <section>Inner property: <i>{outer.inner}</i></section>
  )
}

ReactDOM.render(
  <App />,
  document.getElementById('react')
)

_x000D_

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.10.2/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.10.2/umd/react-dom.production.min.js"></script>
<script src="https://wzrd.in/standalone/[email protected]"></script>

<main id="react"></main>

_x000D_

immutability-helper takes it to a whole new level, and the cool thing about it is that it can not only $set values to state items, but also $push, $splice, $merge (etc.) them. Here is a list of commands available.

Side notes

Again, keep in mind, that setOuter only modifies the first-level properties of the state object (outer in these examples), not the deeply nested (outer.inner). If it behaved in a different way, this question wouldn't exist.

Which one is right for your project?

If you don't want or can't use external dependencies, and have a simple state structure, stick to Object.assign.

If you manipulate a huge and/or complex state, Lodash's cloneDeep is a wise choice.

If you need advanced capabilities, i.e. if your state structure is complex and you need to perform all kinds of operations on it, try immutability-helper, it's a very advanced tool which can be used for state manipulation.

...or, do you really need to do this at all?

If you hold a complex data in React's state, maybe this is a good time to think about other ways of handling it. Setting a complex state objects right in React components is not a straightforward operation, and I strongly suggest to think about different approaches.

Most likely you better be off keeping your complex data in a Redux store, setting it there using reducers and/or sagas and access it using selectors.

Difference between exit(0) and exit(1) in Python

How to add an item to a drop down list in ASP.NET?

Try following code;

DropDownList1.Items.Add(new ListItem(txt_box1.Text));

Label axes on Seaborn Barplot

You can also set the title of your chart by adding the title parameter as follows

ax.set(xlabel='common xlabel', ylabel='common ylabel', title='some title')

How to declare and use 1D and 2D byte arrays in Verilog?

It is simple actually, like C programming you just need to pass the array indices on the right hand side while declaration. But yeah the syntax will be like [0:3] for 4 elements.

reg a[0:3];

This will create a 1D of array of single bit. Similarly 2D array can be created like this:

reg [0:3][0:2];

Now in C suppose you create a 2D array of int, then it will internally create a 2D array of 32 bits. But unfortunately Verilog is an HDL, so it thinks in bits rather then bunch of bits (though int datatype is there in Verilog), it can allow you to create any number of bits to be stored inside an element of array (which is not the case with C, you can't store 5-bits in every element of 2D array in C). So to create a 2D array, in which every individual element can hold 5 bit value, you should write this:

reg [0:4] a [0:3][0:2];

JQuery $.ajax() post - data in a java servlet

Simple method to sending data using java script and ajex call.

First right your form like this

<form id="frm_details" method="post" name="frm_details">
<input  id="email" name="email" placeholder="Your Email id" type="text" />
    <button class="subscribe-box__btn" type="submit">Need Assistance</button>
</form>

javascript logic target on form id #frm_details after sumbit

$(function(){
        $("#frm_details").on("submit", function(event) {
            event.preventDefault();

            var formData = {
                'email': $('input[name=email]').val() //for get email 
            };
            console.log(formData);

            $.ajax({
                url: "/tsmisc/api/subscribe-newsletter",
                type: "post",
                data: formData,
                success: function(d) {
                    alert(d);
                }
            });
        });
    }) 





General 
Request URL:https://test.abc
Request Method:POST
Status Code:200 
Remote Address:13.76.33.57:443

From Data
email:[email protected]

./configure : /bin/sh^M : bad interpreter

You can also do this in Kate.

Open the file
Open the Tools menu
Expand the End Of Line submenu
Select UNIX
Save the file.

Xcode 6 Storyboard the wrong size?

Do the following steps to resolve the issue

In Storyboard, select any view, then go to the File inspector. Uncheck the "Use Size Classes", you will ask to keep size class data for: iPhone/iPad. And then Click the "Disable Size Classes" button. Doing this will make the storyboard's view size with selected device.

"fatal: Not a git repository (or any of the parent directories)" from git status

i have the same problem from my office network. i use this command but its not working for me url, so like this: before $ git clone https://gitlab.com/omsharma/Resume.git

After i Use this URL : $ git clone https://[email protected]/omsharma/Resume.git try It.

Passing Arrays to Function in C++

The simple answer is that arrays are ALWAYS passed by reference and the int arg[] simply lets the compiler know to expect an array

What is the difference between a token and a lexeme?

a) Tokens are symbolic names for the entities that make up the text of the program; e.g. if for the keyword if, and id for any identifier. These make up the output of the lexical analyser. 5

(b) A pattern is a rule that specifies when a sequence of characters from the input constitutes a token; e.g the sequence i, f for the token if , and any sequence of alphanumerics starting with a letter for the token id.

(c) A lexeme is a sequence of characters from the input that match a pattern (and hence constitute an instance of a token); for example if matches the pattern for if , and foo123bar matches the pattern for id.

How to embed images in html email

This is the code I'm using to embed images into HTML mail and PDF documents.

<?php
$logo_path = 'http://localhost/img/logo.jpg';
$type = pathinfo($logo_path, PATHINFO_EXTENSION);
$image_contents = file_get_contents($logo_path);
$image64 = 'data:image/' . $type . ';base64,' . base64_encode($image_contents);

echo '<img src="' . $image64 .'" />';
?>

LINQ select one field from list of DTO objects to array

You can select all Sku elements of your myLines list and then convert the result to an array.

string[] mySKUsArray = myLines.Select(x=>x.Sku).ToArray();

PDF Parsing Using Python - extracting formatted and plain texts

You can also take a look at PDFMiner (or for older versions of Python see PDFMiner and PDFMiner).

A particular feature of interest in PDFMiner is that you can control how it regroups text parts when extracting them. You do this by specifying the space between lines, words, characters, etc. So, maybe by tweaking this you can achieve what you want (that depends of the variability of your documents). PDFMiner can also give you the location of the text in the page, it can extract data by Object ID and other stuff. So dig in PDFMiner and be creative!

But your problem is really not an easy one to solve because, in a PDF, the text is not continuous, but made from a lot of small groups of characters positioned absolutely in the page. The focus of PDF is to keep the layout intact. It's not content oriented but presentation oriented.

Animate an element's width from 0 to 100%, with it and it's wrapper being only as wide as they need to be, without a pre-set width, in CSS3 or jQuery

Please check following snippet

_x000D_

 /* DEBUG */_x000D_
.lwb-col {_x000D_
    transition: box-shadow 0.5s ease;_x000D_
}_x000D_
.lwb-col:hover{_x000D_
    box-shadow: 0 15px 30px -4px rgba(136, 155, 166, 0.4);_x000D_
 _x000D_
}_x000D_
_x000D_
_x000D_
.lwb-col--link {_x000D_
    font-weight: 500;_x000D_
  position: relative;_x000D_
  display: inline-block;_x000D_
}_x000D_
.lwb-col--link::after{_x000D_
    border-bottom: 2px solid;_x000D_
    bottom: -3px;_x000D_
    content: "";_x000D_
    display: block;_x000D_
    left: 0;_x000D_
    position: absolute;_x000D_
    width: 100%;_x000D_
    color: #E5E9EC;_x000D_
_x000D_
}_x000D_
.lwb-col--link::before{_x000D_
    border-bottom: 2px solid;_x000D_
    bottom: -3px;_x000D_
    content: "";_x000D_
    display: block;_x000D_
    left: 0;_x000D_
    position: absolute;_x000D_
    width: 100%;_x000D_
    color: #57B0FB;_x000D_
    transform: scaleX(0);_x000D_
    _x000D_
_x000D_
}_x000D_
.lwb-col:hover .lwb-col--link::before {_x000D_
    border-color: #57B0FB;_x000D_
    display: block;_x000D_
    z-index: 2;_x000D_
    transition: transform 0.3s;_x000D_
    transform: scaleX(1);_x000D_
    transform-origin: left center;_x000D_
}

_x000D_

<div class="lwb-col">_x000D_
  <h2>Webdesign</h2>_x000D_
  <p>Steigern Sie Ihre Bekanntheit im Web mit individuellem &amp; professionellem Webdesign. Organisierte Codestruktur, sowie perfekte SEO Optimierung und jahrelange Erfahrung sprechen für uns.</p>_x000D_
<span class="lwb-col--link">Mehr erfahren</span>_x000D_
</div>

_x000D_

Converting newline formatting from Mac to Windows

You probably want unix2dos:

$ man unix2dos

NAME
       dos2unix - DOS/MAC to UNIX and vice versa text file format converter

SYNOPSIS
           dos2unix [options] [-c CONVMODE] [-o FILE ...] [-n INFILE OUTFILE ...]
           unix2dos [options] [-c CONVMODE] [-o FILE ...] [-n INFILE OUTFILE ...]

DESCRIPTION
       The Dos2unix package includes utilities "dos2unix" and "unix2dos" to convert plain text files in DOS or MAC format to UNIX format and vice versa.  Binary files and non-
       regular files, such as soft links, are automatically skipped, unless conversion is forced.

       Dos2unix has a few conversion modes similar to dos2unix under SunOS/Solaris.

       In DOS/Windows text files line endings exist out of a combination of two characters: a Carriage Return (CR) followed by a Line Feed (LF).  In Unix text files line
       endings exists out of a single Newline character which is equal to a DOS Line Feed (LF) character.  In Mac text files, prior to Mac OS X, line endings exist out of a
       single Carriage Return character. Mac OS X is Unix based and has the same line endings as Unix.

You can either run unix2dos on your DOS/Windows machine using cygwin or on your Mac using MacPorts.

How do I reference the input of an HTML <textarea> control in codebehind?

You are not using a .NET control for your text area. Either add runat="server" to the HTML TextArea control or use a .NET control:

Try this:

<asp:TextBox id="TextArea1" TextMode="multiline" Columns="50" Rows="5" runat="server" />

Then reference it in your codebehind:

message.Body = TextArea1.Text;

Copy an entire worksheet to a new worksheet in Excel 2010

'Make the excel file that runs the software the active workbook
ThisWorkbook.Activate

'The first sheet used as a temporary place to hold the data 
ThisWorkbook.Worksheets(1).Cells.Copy

'Create a new Excel workbook
Dim NewCaseFile As Workbook
Dim strFileName As String

Set NewCaseFile = Workbooks.Add
With NewCaseFile
    Sheets(1).Select
    Cells(1, 1).Select
End With

ActiveSheet.Paste

Is there a way to get rid of accents and convert a whole string to regular letters?

One of the best way using regex and Normalizer if you have no library is :

    public String flattenToAscii(String s) {
                if(s == null || s.trim().length() == 0)
                        return "";
                return Normalizer.normalize(s, Normalizer.Form.NFD).replaceAll("[\u0300-\u036F]", "");
}

This is more efficient than replaceAll("[^\p{ASCII}]", "")) and if you don't need diacritics (just like your example).

Otherwise, you have to use the p{ASCII} pattern.

Regards.

Create Table from JSON Data with angularjs and ng-repeat

You can use $http.get() method to fetch your JSON file. Then assign response data to a $scope object. In HTML to create table use ng-repeat for $scope object. ng-repeat will loop the rows in-side this loop you can bind data to columns dynamically.

I have checked your code and you have created static table

<table>
<tr>
<th>Name</th>
<th>Relationship</th>
</tr>
<tr ng-repeat="indivisual in members">
<td>{{ indivisual.Name }}</td>
<td>{{ indivisual.Relation }}</td>
</tr>
</table>

so better your can go to my code to create dynamic table as per data you column and row will be increase or decrease..

How to reload or re-render the entire page using AngularJS

Use the following code without intimate reload notification to the user. It will render the page

var currentPageTemplate = $route.current.templateUrl;
$templateCache.remove(currentPageTemplate);
$window.location.reload();

How to center a checkbox in a table cell?

How about this... http://jsfiddle.net/gSaPb/

Check out my example on jsFiddle: http://jsfiddle.net/QzPGu. Code snippet:

_x000D_

td {
  text-align: center;
  /* center checkbox horizontally */
  vertical-align: middle;
  /* center checkbox vertically */
}

table {
  border: 1px solid;
  width: 200px;
}

tr {
  height: 80px;
}

_x000D_

<table>
  <tr>
    <td>
      <input type="checkbox" name="myTextEditBox" value="checked" /> checkbox
    </td>
  </tr>
</table>

_x000D_

Open Source HTML to PDF Renderer with Full CSS Support

I've always used it on the command line and not as a library, but HTMLDOC gives me excellent results, and it handles at least some CSS (I couldn't easily see how much).

Here's a sample command line

htmldoc --webpage -t pdf --size letter --fontsize 10pt index.html > index.pdf

Why Python 3.6.1 throws AttributeError: module 'enum' has no attribute 'IntFlag'?

I have Python 2 and Python 3 installed on my computer. For some strange reason I have in the sys.path of Python 3 also a path to the sitepackage library directory of Python2 when the re module is called. If I run Python 3 and import enum and print(enum.__file__) the system does not show this Python 2 path to site-packages. So a very rough and dirty hack is, to directly modify the module in which enum is imported (follow the traceback paths) and insert the following code just before importing enum:

import sys
for i, p in enumerate(sys.path):
    if "python27" in p.lower() or "python2.7" in p.lower(): sys.path.pop(i)
import enum

That solved my problem.

Best practices for copying files with Maven

I've had very good experience with copy-maven-plugin. It has a much more convenient and concise syntax in comparison to maven-resources-plugin.

Websocket connections with Postman

I ran into the exact same problem. Had to make a Web Socket call. I was able to accomplish this using Advanced Rest Client. I'm using ARC version : 12.1.3

convert date string to mysql datetime field

If these strings are currently in the db, you can skip php by using mysql's STR_TO_DATE() function.

I assume the strings use a format like month/day/year where month and day are always 2 digits, and year is 4 digits.

UPDATE some_table
   SET new_column = STR_TO_DATE(old_column, '%m/%d/%Y')

You can support other date formats by using other format specifiers.

How to generate .env file for laravel?

This is an old thread, but as it still gets viewed and recently active "26" days ago as of this post, here is a quick solution.

There is no .env file initially, you must duplicate .env.example as .env.

In windows, you can open a command prompt aka the CLI and paste the exact code below while inside the root directory of the project. Must include the ( at the start line without space.

(
echo APP_NAME=Laravel
echo APP_ENV=local
echo APP_KEY=
echo APP_DEBUG=true
echo APP_URL=http://localhost
echo.
echo LOG_CHANNEL=stack
echo.
echo DB_CONNECTION=mysql
echo DB_HOST=127.0.0.1
echo DB_PORT=3306
echo DB_DATABASE=homestead
echo DB_USERNAME=homestead
echo DB_PASSWORD=secret
echo.
echo BROADCAST_DRIVER=log
echo CACHE_DRIVER=file
echo SESSION_DRIVER=file
echo SESSION_LIFETIME=120
echo QUEUE_DRIVER=sync
echo.
echo REDIS_HOST=127.0.0.1
echo REDIS_PASSWORD=null
echo REDIS_PORT=6379
echo.
echo MAIL_DRIVER=smtp
echo MAIL_HOST=smtp.mailtrap.io
echo MAIL_PORT=2525
echo MAIL_USERNAME=null
echo MAIL_PASSWORD=null
echo MAIL_ENCRYPTION=null
echo.
echo PUSHER_APP_ID=
echo PUSHER_APP_KEY=
echo PUSHER_APP_SECRET=
echo PUSHER_APP_CLUSTER=mt1
echo.
echo MIX_PUSHER_APP_KEY="${PUSHER_APP_KEY}"
echo MIX_PUSHER_APP_CLUSTER="${PUSHER_APP_CLUSTER}"
)>".env"

Just press enter to exit the prompt and you should have the .env file with the default settings created in the same directory you typed above CLI command.

Hope this helps.

Post to another page within a PHP script

Possibly the easiest way to make PHP perform a POST request is to use cURL, either as an extension or simply shelling out to another process. Here's a post sample:

// where are we posting to?
$url = 'http://foo.com/script.php';

// what post fields?
$fields = array(
   'field1' => $field1,
   'field2' => $field2,
);

// build the urlencoded data
$postvars = http_build_query($fields);

// open connection
$ch = curl_init();

// set the url, number of POST vars, POST data
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, count($fields));
curl_setopt($ch, CURLOPT_POSTFIELDS, $postvars);

// execute post
$result = curl_exec($ch);

// close connection
curl_close($ch);

Also check out Zend_Http set of classes in the Zend framework, which provides a pretty capable HTTP client written directly in PHP (no extensions required).

2014 EDIT - well, it's been a while since I wrote that. These days it's worth checking Guzzle which again can work with or without the curl extension.

HTML5 File API read as text and binary

Note in 2018: readAsBinaryString is outdated. For use cases where previously you'd have used it, these days you'd use readAsArrayBuffer (or in some cases, readAsDataURL) instead.

readAsBinaryString says that the data must be represented as a binary string, where:

...every byte is represented by an integer in the range [0..255].

JavaScript originally didn't have a "binary" type (until ECMAScript 5's WebGL support of Typed Array* (details below) -- it has been superseded by ECMAScript 2015's ArrayBuffer) and so they went with a String with the guarantee that no character stored in the String would be outside the range 0..255. (They could have gone with an array of Numbers instead, but they didn't; perhaps large Strings are more memory-efficient than large arrays of Numbers, since Numbers are floating-point.)

If you're reading a file that's mostly text in a western script (mostly English, for instance), then that string is going to look a lot like text. If you read a file with Unicode characters in it, you should notice a difference, since JavaScript strings are UTF-16** (details below) and so some characters will have values above 255, whereas a "binary string" according to the File API spec wouldn't have any values above 255 (you'd have two individual "characters" for the two bytes of the Unicode code point).

If you're reading a file that's not text at all (an image, perhaps), you'll probably still get a very similar result between readAsText and readAsBinaryString, but with readAsBinaryString you know that there won't be any attempt to interpret multi-byte sequences as characters. You don't know that if you use readAsText, because readAsText will use an encoding determination to try to figure out what the file's encoding is and then map it to JavaScript's UTF-16 strings.

You can see the effect if you create a file and store it in something other than ASCII or UTF-8. (In Windows you can do this via Notepad; the "Save As" as an encoding drop-down with "Unicode" on it, by which looking at the data they seem to mean UTF-16; I'm sure Mac OS and *nix editors have a similar feature.) Here's a page that dumps the result of reading a file both ways:

<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-type" content="text/html;charset=UTF-8">
<title>Show File Data</title>
<style type='text/css'>
body {
    font-family: sans-serif;
}
</style>
<script type='text/javascript'>

    function loadFile() {
        var input, file, fr;

        if (typeof window.FileReader !== 'function') {
            bodyAppend("p", "The file API isn't supported on this browser yet.");
            return;
        }

        input = document.getElementById('fileinput');
        if (!input) {
            bodyAppend("p", "Um, couldn't find the fileinput element.");
        }
        else if (!input.files) {
            bodyAppend("p", "This browser doesn't seem to support the `files` property of file inputs.");
        }
        else if (!input.files[0]) {
            bodyAppend("p", "Please select a file before clicking 'Load'");
        }
        else {
            file = input.files[0];
            fr = new FileReader();
            fr.onload = receivedText;
            fr.readAsText(file);
        }

        function receivedText() {
            showResult(fr, "Text");

            fr = new FileReader();
            fr.onload = receivedBinary;
            fr.readAsBinaryString(file);
        }

        function receivedBinary() {
            showResult(fr, "Binary");
        }
    }

    function showResult(fr, label) {
        var markup, result, n, aByte, byteStr;

        markup = [];
        result = fr.result;
        for (n = 0; n < result.length; ++n) {
            aByte = result.charCodeAt(n);
            byteStr = aByte.toString(16);
            if (byteStr.length < 2) {
                byteStr = "0" + byteStr;
            }
            markup.push(byteStr);
        }
        bodyAppend("p", label + " (" + result.length + "):");
        bodyAppend("pre", markup.join(" "));
    }

    function bodyAppend(tagName, innerHTML) {
        var elm;

        elm = document.createElement(tagName);
        elm.innerHTML = innerHTML;
        document.body.appendChild(elm);
    }

</script>
</head>
<body>
<form action='#' onsubmit="return false;">
<input type='file' id='fileinput'>
<input type='button' id='btnLoad' value='Load' onclick='loadFile();'>
</form>
</body>
</html>

If I use that with a "Testing 1 2 3" file stored in UTF-16, here are the results I get:

Text (13):

54 65 73 74 69 6e 67 20 31 20 32 20 33

Binary (28):

ff fe 54 00 65 00 73 00 74 00 69 00 6e 00 67 00 20 00 31 00 20 00 32 00 20 00 33 00

As you can see, readAsText interpreted the characters and so I got 13 (the length of "Testing 1 2 3"), and readAsBinaryString didn't, and so I got 28 (the two-byte BOM plus two bytes for each character).

* XMLHttpRequest.response with responseType = "arraybuffer" is supported in HTML 5.

** "JavaScript strings are UTF-16" may seem like an odd statement; aren't they just Unicode? No, a JavaScript string is a series of UTF-16 code units; you see surrogate pairs as two individual JavaScript "characters" even though, in fact, the surrogate pair as a whole is just one character. See the link for details.

SELECT COUNT in LINQ to SQL C#

You should be able to do the count on the purch variable:

purch.Count();

e.g.

var purch = from purchase in myBlaContext.purchases
select purchase;

purch.Count();

How to set up a Web API controller for multipart/form-data

You can use something like this

[HttpPost]
public async Task<HttpResponseMessage> AddFile()
{
    if (!Request.Content.IsMimeMultipartContent())
    {
        this.Request.CreateResponse(HttpStatusCode.UnsupportedMediaType);
    }

    string root = HttpContext.Current.Server.MapPath("~/temp/uploads");
    var provider = new MultipartFormDataStreamProvider(root);
    var result = await Request.Content.ReadAsMultipartAsync(provider);

    foreach (var key in provider.FormData.AllKeys)
    {
        foreach (var val in provider.FormData.GetValues(key))
        {
            if (key == "companyName")
            {
                var companyName = val;
            }
        }
    }

    // On upload, files are given a generic name like "BodyPart_26d6abe1-3ae1-416a-9429-b35f15e6e5d5"
    // so this is how you can get the original file name
    var originalFileName = GetDeserializedFileName(result.FileData.First());

    var uploadedFileInfo = new FileInfo(result.FileData.First().LocalFileName);
    string path = result.FileData.First().LocalFileName;

    //Do whatever you want to do with your file here

    return this.Request.CreateResponse(HttpStatusCode.OK, originalFileName );
}

private string GetDeserializedFileName(MultipartFileData fileData)
{
    var fileName = GetFileName(fileData);
    return JsonConvert.DeserializeObject(fileName).ToString();
}

public string GetFileName(MultipartFileData fileData)
{
    return fileData.Headers.ContentDisposition.FileName;
}

How to check if a network port is open on linux?

You can using the socket module to simply check if a port is open or not.

It would look something like this.

import socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
result = sock.connect_ex(('127.0.0.1',80))
if result == 0:
   print "Port is open"
else:
   print "Port is not open"
sock.close()

PHP - Failed to open stream : No such file or directory

To add to the (really good) existing answer

Shared Hosting Software

open_basedir is one that can stump you because it can be specified in a web server configuration. While this is easily remedied if you run your own dedicated server, there are some shared hosting software packages out there (like Plesk, cPanel, etc) that will configure a configuration directive on a per-domain basis. Because the software builds the configuration file (i.e. httpd.conf) you cannot change that file directly because the hosting software will just overwrite it when it restarts.

With Plesk, they provide a place to override the provided httpd.conf called vhost.conf. Only the server admin can write this file. The configuration for Apache looks something like this

<Directory /var/www/vhosts/domain.com>
    <IfModule mod_php5.c>
        php_admin_flag engine on
        php_admin_flag safe_mode off
        php_admin_value open_basedir "/var/www/vhosts/domain.com:/tmp:/usr/share/pear:/local/PEAR"
    </IfModule>
</Directory>

Have your server admin consult the manual for the hosting and web server software they use.

File Permissions

It's important to note that executing a file through your web server is very different from a command line or cron job execution. The big difference is that your web server has its own user and permissions. For security reasons that user is pretty restricted. Apache, for instance, is often apache, www-data or httpd (depending on your server). A cron job or CLI execution has whatever permissions that the user running it has (i.e. running a PHP script as root will execute with permissions of root).

A lot of times people will solve a permissions problem by doing the following (Linux example)

chmod 777 /path/to/file

This is not a smart idea, because the file or directory is now world writable. If you own the server and are the only user then this isn't such a big deal, but if you're on a shared hosting environment you've just given everyone on your server access.

What you need to do is determine the user(s) that need access and give only those them access. Once you know which users need access you'll want to make sure that

That user owns the file and possibly the parent directory (especially the parent directory if you want to write files). In most shared hosting environments this won't be an issue, because your user should own all the files underneath your root. A Linux example is shown below
```
 chown apache:apache /path/to/file
```
The user, and only that user, has access. In Linux, a good practice would be chmod 600 (only owner can read and write) or chmod 644 (owner can write but everyone can read)

You can read a more extended discussion of Linux/Unix permissions and users here

Insert current date/time using now() in a field using MySQL/PHP

now()

worked for me . but my field type is date only and yours is datetime. i am not sure if this is the case

How to find out which package version is loaded in R?

Technically speaking, all of the answers at this time are wrong. packageVersion does not return the version of the loaded package. It goes to the disk, and fetches the package version from there.

This will not make a difference in most cases, but sometimes it does. As far as I can tell, the only way to get the version of a loaded package is the rather hackish:

asNamespace(pkg)$`.__NAMESPACE__.`$spec[["version"]]

where pkg is the package name.

EDIT: I am not sure when this function was added, but you can also use getNamespaceVersion, this is cleaner:

getNamespaceVersion(pkg)

docker error - 'name is already in use by container'

Ok, so I didn't understand either, then I left my pc, went to do other things, and upon my return, it clicked :D

You download a docker image file. docker pull *image-name* will just pull the image from docker hub without running it.
Now, you use docker run, and give it a name (e.g. newWebServer).

docker run -d -p 8080:8080 -v volume --name newWebServer image-name/version

You perhaps only need docker run --name *name* *image*, but the other stuff will become useful quickly.

-d (detached) - means the container will exit when the root process used to run the container exits.

-p (port) - specify the container port and the host port. Kind of the internal and external port. The internal one being the port the container uses, and the external one is the port you use outside of it and probably the one you need to put in your web browser if that's how you access your app.

--name (what you want to call this instance of the container) - you could have several instances of the same container all with different names, which is useful when you're trying to test something.

image-name/version is the actual image you want to create the container from. You can see a list of all the images on your system with docker images -a. You may have more than one version, so make sure you choose the correct one/tag.

-v (volume) - perhaps not needed initially, but soon you'll want to persist data after your container exits.

OK. So now, docker run just created a container from your image. If it isn't running, you can now start it with it's name:

docker start newWebServer

You can check all your containers (they may or may not be running) with

docker ps -a

You can stop and start them (or pause them) with their name or the container id (or just the first few characters of it) from the CONTAINER ID column e.g:

docker stop newWebServer

docker start c3028a89462c

And list all your images, with

docker images -a

In a nutshell, download an image; docker run creates a container from it; start it with docker start (name or container id); stop it with docker stop (name or container id).

jQuery post() with serialize and extra data

I like to keep objects as objects and not do any crazy type-shifting. Here's my way

var post_vars = $('#my-form').serializeArray();
$.ajax({
  url: '//site.com/script.php',
  method: 'POST',
  data: post_vars,
  complete: function() {
    $.ajax({
      url: '//site.com/script2.php',
      method: 'POST',
      data: post_vars.concat({
        name: 'EXTRA_VAR',
        value: 'WOW THIS WORKS!'
      })
    });
  }
});

if you can't see from above I used the .concat function and passed in an object with the post variable as 'name' and the value as 'value'!

Hope this helps.

What is the difference between 0.0.0.0, 127.0.0.1 and localhost?

127.0.0.1 is normally the IP address assigned to the "loopback" or local-only interface. This is a "fake" network adapter that can only communicate within the same host. It's often used when you want a network-capable application to only serve clients on the same host. A process that is listening on 127.0.0.1 for connections will only receive local connections on that socket.

"localhost" is normally the hostname for the 127.0.0.1 IP address. It's usually set in /etc/hosts (or the Windows equivalent named "hosts" somewhere under %WINDIR%). You can use it just like any other hostname - try "ping localhost" to see how it resolves to 127.0.0.1.

0.0.0.0 has a couple of different meanings, but in this context, when a server is told to listen on 0.0.0.0 that means "listen on every available network interface". The loopback adapter with IP address 127.0.0.1 from the perspective of the server process looks just like any other network adapter on the machine, so a server told to listen on 0.0.0.0 will accept connections on that interface too.

That hopefully answers the IP side of your question. I'm not familiar with Jekyll or Vagrant, but I'm guessing that your port forwarding 8080 => 4000 is somehow bound to a particular network adapter, so it isn't in the path when you connect locally to 127.0.0.1

Should 'using' directives be inside or outside the namespace?

Another subtlety that I don't believe has been covered by the other answers is for when you have a class and namespace with the same name.

When you have the import inside the namespace then it will find the class. If the import is outside the namespace then the import will be ignored and the class and namespace have to be fully qualified.

//file1.cs
namespace Foo
{
    class Foo
    {
    }
}

//file2.cs
namespace ConsoleApp3
{
    using Foo;
    class Program
    {
        static void Main(string[] args)
        {
            //This will allow you to use the class
            Foo test = new Foo();
        }
    }
}

//file2.cs
using Foo; //Unused and redundant    
namespace Bar
{
    class Bar
    {
        Bar()
        {
            Foo.Foo test = new Foo.Foo();
            Foo test = new Foo(); //will give you an error that a namespace is being used like a class.
        }
    }
}

Adding a rule in iptables in debian to open a new port

About your command line:

root@debian:/# sudo iptables -A INPUT -p tcp --dport 3306 --jump ACCEPT
root@debian:/# iptables-save

You are already authenticated as root so sudo is redundant there.
You are missing the -j or --jump just before the ACCEPT parameter (just tought that was a typo and you are inserting it correctly).

About yout question:

If you are inserting the iptables rule correctly as you pointed it in the question, maybe the issue is related to the hypervisor (virtual machine provider) you are using.

If you provide the hypervisor name (VirtualBox, VMWare?) I can further guide you on this but here are some suggestions you can try first:

check your vmachine network settings and:

if it is set to NAT, then you won't be able to connect from your base machine to the vmachine.
if it is set to Hosted, you have to configure first its network settings, it is usually to provide them an IP in the range 192.168.56.0/24, since is the default the hypervisors use for this.
if it is set to Bridge, same as Hosted but you can configure it whenever IP range makes sense for you configuration.

Hope this helps.

jQuery changing css class to div

$(document).ready(function () {

            $("#divId").toggleClass('cssclassname'); // toggle class
});

**OR**

$(document).ready(function() {
        $("#objectId").click(function() {  // click or other event to change the div class
                $("#divId").toggleClass("cssclassname");     // toggle class
        )}; 
)};

Java equivalent to JavaScript's encodeURIComponent that produces identical output?

I used String encodedUrl = new URI(null, url, null).toASCIIString(); to encode urls. To add parameters after the existing ones in the url I use UriComponentsBuilder

Unable to add window -- token null is not valid; is your activity running?

PopupWindow can only be attached to an Activity. In your case you are trying to add PopupWindow to service which is not right.

To solve this problem you can use a blank and transparent Activity. On click of floating icon, launch the Activity and on onCreate of Activity show the PopupWindow.

On dismiss of PopupWindow, you can finish the transparent Activity. Hope this helps you.

CURL to access a page that requires a login from a different page

After some googling I found this:

curl -c cookie.txt -d "LoginName=someuser" -d "password=somepass" https://oursite/a
curl -b cookie.txt https://oursite/b

No idea if it works, but it might lead you in the right direction.

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

layout:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="match_parent" >

  <LinearLayout
      android:id="@+id/layoutTest"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:orientation="vertical"
      >
  </LinearLayout>
</RelativeLayout>

class file:

setContentView(R.layout.layout_dynamic);
layoutTest=(LinearLayout)findViewById(R.id.layoutTest);
TextView textView = new TextView(getApplicationContext());

textView.setText("testDynamic textView");
layoutTest.addView(textView);

Converting numpy dtypes to native python types

Is there possibility of sum of ArrayList without looping

Or switch to Groovy, it has a sum() function on a collection. [1,2,3,4,5,6].sum()

http://groovy.codehaus.org/JN1015-Collections

Runs on the same JVM as your java classes.

SQL SELECT everything after a certain character

Try this in MySQL.

right(field,((CHAR_LENGTH(field))-(InStr(field,','))))

How to change my Git username in terminal?

usually the user name resides under git config

git config --global user.name "first last"

although if you still see above doesn't work you could edit .gitconfig under your user directory of mac and update

[user]
        name = gitusername
        email = [email protected]

GoTo Next Iteration in For Loop in java

use continue keyword .

EX:

for(int i = 0; i < 10; i++){
  if(i == 5){
    continue;
   }
}

SQL Transaction Error: The current transaction cannot be committed and cannot support operations that write to the log file

Had the exact same error in a procedure. It turns out the user running it (a technical user in our case) did not have sufficient rigths to create a temporary table.

EXEC sp_addrolemember 'db_ddladmin', 'username_here';

did the trick

Check if string contains \n Java

If the string was constructed in the same program, I would recommend using this:

String newline = System.getProperty("line.separator");
boolean hasNewline = word.contains(newline);

But if you are specced to use \n, this driver illustrates what to do:

class NewLineTest {
    public static void main(String[] args) {
        String hasNewline = "this has a newline\n.";
        String noNewline = "this doesn't";

        System.out.println(hasNewline.contains("\n"));
        System.out.println(hasNewline.contains("\\n"));
        System.out.println(noNewline.contains("\n"));
        System.out.println(noNewline.contains("\\n"));

    }

}

Resulted in

true
false
false
false

In reponse to your comment:

class NewLineTest {
    public static void main(String[] args) {
        String word = "test\n.";
        System.out.println(word.length());
        System.out.println(word);
        word = word.replace("\n","\n ");
        System.out.println(word.length());
        System.out.println(word);

    }

}

Results in

6
test
.
7
test
 .

How do I space out the child elements of a StackPanel?

Grid.ColumnSpacing, Grid.RowSpacing, StackPanel.Spacing are now on UWP preview, all will allow to better acomplish what is requested here.

These properties are currently only available with the Windows 10 Fall Creators Update Insider SDK, but should make it to the final bits!

What can <f:metadata>, <f:viewParam> and <f:viewAction> be used for?

Send params from View to an other View, from Sender View to Receiver View use viewParam and includeViewParams=true

In Sender

Declare params to be sent. We can send String, Object,…

Sender.xhtml

<f:metadata>
      <f:viewParam name="ID" value="#{senderMB._strID}" />
</f:metadata>

We’re going send param ID, it will be included with “includeViewParams=true” in return String of click button event Click button fire senderMB.clickBtnDetail(dto) with dto from senderMB._arrData

Sender.xhtml

<p:dataTable rowIndexVar="index" id="dataTale"value="#{senderMB._arrData}" var="dto">
      <p:commandButton action="#{senderMB.clickBtnDetail(dto)}" value="??" 
      ajax="false"/>
</p:dataTable>

In senderMB.clickBtnDetail(dto) we assign _strID with argument we got from button event (dto), here this is Sender_DTO and assign to senderMB._strID

Sender_MB.java
    public String clickBtnDetail(sender_DTO sender_dto) {
        this._strID = sender_dto.getStrID();
        return "Receiver?faces-redirect=true&includeViewParams=true";
    }

The link when clicked will become http://localhost:8080/my_project/view/Receiver.xhtml?*ID=12345*

In Recever

Get viewParam Receiver.xhtml In Receiver we declare f:viewParam to get param from get request (receive), the name of param of receiver must be the same with sender (page)

Receiver.xhtml

<f:metadata><f:viewParam name="ID" value="#{receiver_MB._strID}"/></f:metadata>

It will get param ID from sender View and assign to receiver_MB._strID

Use viewParam In Receiver, we want to use this param in sql query before the page render, so that we use preRenderView event. We are not going to use constructor because constructor will be invoked before viewParam is received So that we add

Receiver.xhtml

<f:event listener="#{receiver_MB.preRenderView}" type="preRenderView" />

into f:metadata tag

Receiver.xhtml

<f:metadata>
<f:viewParam name="ID" value="#{receiver_MB._strID}" />
<f:event listener="#{receiver_MB.preRenderView}"
            type="preRenderView" />
</f:metadata>

Now we want to use this param in our read database method, it is available to use

Receiver_MB.java
public void preRenderView(ComponentSystemEvent event) throws Exception {
        if (FacesContext.getCurrentInstance().isPostback()) {
            return;
        }
        readFromDatabase();
    }
private void readFromDatabase() {
//use _strID to read and set property   
}

When is null or undefined used in JavaScript?

~~I might be missing something, but afaik, you get undefined only~~

Update: Ok, I missed a lot, trying to complete:

You get undefined...

... when you try to access properties of an object that don't exist:

var a = {}
a.foo // undefined

... when you have declared a variable but not initialized it:

var a;
// a is undefined

... when you access a parameter for which no value was passed:

function foo (a, b) {
    // something
}

foo(42); // b inside foo is undefined

... when a function does not return a value:

function foo() {};
var a = foo(); // a is undefined

It might be that some built-in functions return null on some error, but if so, then it is documented. null is a concrete value in JavaScript, undefined is not.

Normally you don't need to distinguish between those. Depending on the possible values of a variable, it is sufficient to use if(variable) to test whether a value is set or not (both, null and undefined evaluate to false).

Also different browsers seem to be returning these differently.

Please give a concrete example.

Eclipse C++ : "Program "g++" not found in PATH"

All the tips did not work for me using the Gaisler Tools for GR712RC Installation for OS RTEMS. I'm using the Eclipse Kepler.

The simple way was making a copy of sparc-rtems-gcc.exe to gcc.exe, and sparc-rtems-g++.exe to g++.exe, in the C:\opt\rtems-4.10-mingw\bin directory.

How to add ASP.NET 4.0 as Application Pool on IIS 7, Windows 7

In the top level of the IIS Manager (above Sites), you should see the Application Pools tree node. Right click on "Application Pools", choose "Add Application Pool".

Give it a name, choose .NET Framework 4.0 and either Integrated or Classic mode.

When you add or edit a web site, your new application pools will now show up in the list.

How to remove files and directories quickly via terminal (bash shell)

rm -rf some_dir

-r "recursive" -f "force" (suppress confirmation messages)

Be careful!

Select unique or distinct values from a list in UNIX shell script

I get a better tips to get non-duplicate entries in a file

awk '$0 != x ":FOO" && NR>1 {print x} {x=$0} END {print}' file_name | uniq -f1 -u

No converter found capable of converting from type to type

Simple Solution::

use {nativeQuery=true} in your query.

for example

  @Query(value = "select d.id,d.name,d.breed,d.origin from Dog d",nativeQuery = true)
        
    List<Dog> findALL();

Global Variable in app.js accessible in routes?

To make a global variable, just declare it without the var keyword. (Generally speaking this isn't best practice, but in some cases it can be useful - just be careful as it will make the variable available everywhere.)

Here's an example from visionmedia/screenshot-app

file app.js:

/**
 * Module dependencies.
 */

var express = require('express')
  , stylus = require('stylus')
  , redis = require('redis')
  , http = require('http');

app = express();

//... require() route files

file routes/main.js

//we can now access 'app' without redeclaring it or passing it in...

/*
 * GET home page.
 */

app.get('/', function(req, res, next){
  res.render('index');
});

//...

HTML table with fixed headers?

This can be cleanly solved in four lines of code.

If you only care about modern browsers, a fixed header can be achieved much easier by using CSS transforms. Sounds odd, but works great:

HTML and CSS stay as-is.
No external JavaScript dependencies.
Four lines of code.
Works for all configurations (table-layout: fixed, etc.).

document.getElementById("wrap").addEventListener("scroll", function(){
   var translate = "translate(0,"+this.scrollTop+"px)";
   this.querySelector("thead").style.transform = translate;
});

Support for CSS transforms is widely available except for Internet Explorer 8-.

Here is the full example for reference:

_x000D_

document.getElementById("wrap").addEventListener("scroll",function(){_x000D_
   var translate = "translate(0,"+this.scrollTop+"px)";_x000D_
   this.querySelector("thead").style.transform = translate;_x000D_
});

_x000D_

/* Your existing container */_x000D_
#wrap {_x000D_
    overflow: auto;_x000D_
    height: 400px;_x000D_
}_x000D_
_x000D_
/* CSS for demo */_x000D_
td {_x000D_
    background-color: green;_x000D_
    width: 200px;_x000D_
    height: 100px;_x000D_
}

_x000D_

<div id="wrap">_x000D_
    <table>_x000D_
        <thead>_x000D_
            <tr>_x000D_
                <th>Foo</th>_x000D_
                <th>Bar</th>_x000D_
            </tr>_x000D_
        </thead>_x000D_
        <tbody>_x000D_
            <tr><td></td><td></td></tr>_x000D_
            <tr><td></td><td></td></tr>_x000D_
            <tr><td></td><td></td></tr>_x000D_
            <tr><td></td><td></td></tr>_x000D_
            <tr><td></td><td></td></tr>_x000D_
            <tr><td></td><td></td></tr>_x000D_
            <tr><td></td><td></td></tr>_x000D_
            <tr><td></td><td></td></tr>_x000D_
            <tr><td></td><td></td></tr>_x000D_
            <tr><td></td><td></td></tr>_x000D_
            <tr><td></td><td></td></tr>_x000D_
            <tr><td></td><td></td></tr>_x000D_
        </tbody>_x000D_
    </table>_x000D_
</div>

_x000D_

Convert string to buffer Node

You can do:

var buf = Buffer.from(bufStr, 'utf8');

But this is a bit silly, so another suggestion would be to copy the minimal amount of code out of the called function to allow yourself access to the original buffer. This might be quite easy or fairly difficult depending on the details of that library.

ClassNotFoundException: org.slf4j.LoggerFactory

You'll need to download SLF4J's jars from the official site as either a zip (v1.7.4) or tar.gz (v1.7.4)

The download contains multiple jars based on how you want to use SLF4J. If you're simply trying to resolve the requirement of some other library (GWT, I assume) and don't really care about using SLF4J correctly, then I would probably pick the slf4j-api-1.7.4.jar since the Simple jar suggested by another answer does not contain, to my knowledge, the specific class you're looking for.

Running bash script from within python

Actually, you just have to add the shell=True argument:

subprocess.call("sleep.sh", shell=True)

But beware -

Warning Invoking the system shell with shell=True can be a security hazard if combined with untrusted input. See the warning under Frequently Used Arguments for details.

source

How to replace all strings to numbers contained in each string in Notepad++?

Find: value="([\d]+|[\d])"

Replace: \1

It will really return you

4
403
200
201
116
15

js:

a='value="4"\nvalue="403"\nvalue="200"\nvalue="201"\nvalue="116"\nvalue="15"';
a = a.replace(/value="([\d]+|[\d])"/g, '$1');
console.log(a);

Angular2 Exception: Can't bind to 'routerLink' since it isn't a known native property

In general, whenever you get an error like Can't bind to 'xxx' since it isn't a known native property, the most likely cause is forgetting to specify a component or a directive (or a constant that contains the component or the directive) in the directives metadata array. Such is the case here.

Since you did not specify RouterLink or the constant ROUTER_DIRECTIVES – which contains the following:

export const ROUTER_DIRECTIVES = [RouterOutlet, RouterLink, RouterLinkWithHref, 
  RouterLinkActive];

– in the directives array, then when Angular parses

<a [routerLink]="['RoutingTest']">Routing Test</a>

it doesn't know about the RouterLink directive (which uses attribute selector routerLink). Since Angular does know what the a element is, it assumes that [routerLink]="..." is a property binding for the a element. But it then discovers that routerLink is not a native property of a elements, hence it throws the exception about the unknown property.

I've never really liked the ambiguity of the syntax. I.e., consider

<something [whatIsThis]="..." ...>

Just by looking at the HTML we can't tell if whatIsThis is

a native property of something
a directive's attribute selector
a input property of something

We have to know which directives: [...] are specified in the component's/directive's metadata in order to mentally interpret the HTML. And when we forget to put something into the directives array, I feel this ambiguity makes it a bit harder to debug.

Python - add PYTHONPATH during command line module run

For Mac/Linux;

PYTHONPATH=/foo/bar/baz python somescript.py somecommand

For Windows, setup a wrapper pythonpath.bat;

@ECHO OFF
setlocal
set PYTHONPATH=%1
python %2 %3
endlocal

and call pythonpath.bat script file like;

pythonpath.bat /foo/bar/baz somescript.py somecommand

How to execute mongo commands through shell scripts?

The shell script below also worked nicely for me... definite had to use the redirect that Antonin mentioned at first... that gave me the idea to test the here document.

function testMongoScript {
    mongo <<EOF
    use mydb
    db.leads.findOne()
    db.leads.find().count()
EOF
}

Where does Jenkins store configuration files for the jobs it runs?

The best approach would be to keep your job configurations in a Jenkinsfile that live in source control.

Android view pager with page indicator

you have to do following:

1-Download the full project from here https://github.com/JakeWharton/ViewPagerIndicator ViewPager Indicator 2- Import into the Eclipse.

After importing if you want to make following type of screen then follow below steps -

Screen Shot

change in

Sample circles Default

  package com.viewpagerindicator.sample;
  import android.os.Bundle;  
  import android.support.v4.view.ViewPager;
  import com.viewpagerindicator.CirclePageIndicator;

  public class SampleCirclesDefault extends BaseSampleActivity {
   @Override
   protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.simple_circles);

    mAdapter = new TestFragmentAdapter(getSupportFragmentManager());

    mPager = (ViewPager)findViewById(R.id.pager);
  //  mPager.setAdapter(mAdapter);

    ImageAdapter adapter = new ImageAdapter(SampleCirclesDefault.this);
    mPager.setAdapter(adapter);


    mIndicator = (CirclePageIndicator)findViewById(R.id.indicator);
    mIndicator.setViewPager(mPager);
  }
}

ImageAdapter

 package com.viewpagerindicator.sample;

 import android.content.Context;
 import android.support.v4.view.PagerAdapter;
 import android.support.v4.view.ViewPager;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.ImageView;
 import android.widget.TextView;

 public class ImageAdapter extends PagerAdapter {
 private Context mContext;

 private Integer[] mImageIds = { R.drawable.about1, R.drawable.about2,
        R.drawable.about3, R.drawable.about4, R.drawable.about5,
        R.drawable.about6, R.drawable.about7

 };

 public ImageAdapter(Context context) {
    mContext = context;
 }

 public int getCount() {
    return mImageIds.length;
 }

 public Object getItem(int position) {
    return position;
 }

 public long getItemId(int position) {
    return position;
 }

 @Override
 public Object instantiateItem(ViewGroup container, final int position) {

    LayoutInflater inflater = (LayoutInflater) container.getContext()
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    View convertView = inflater.inflate(R.layout.gallery_view, null);

    ImageView view_image = (ImageView) convertView
            .findViewById(R.id.view_image);
    TextView description = (TextView) convertView
            .findViewById(R.id.description);

    view_image.setImageResource(mImageIds[position]);
    view_image.setScaleType(ImageView.ScaleType.FIT_XY);

    description.setText("The natural habitat of the Niligiri tahr,Rajamala          Rajamala is 2695 Mts above sea level"
        + "The natural habitat of the Niligiri tahr,Rajamala Rajamala is 2695 Mts above sea level"
                    + "The natural habitat of the Niligiri tahr,Rajamala Rajamala is 2695 Mts above sea level");

    ((ViewPager) container).addView(convertView, 0);

    return convertView;
 }

 @Override
 public boolean isViewFromObject(View view, Object object) {
    return view == ((View) object);
 }

 @Override
 public void destroyItem(ViewGroup container, int position, Object object) {
    ((ViewPager) container).removeView((ViewGroup) object);
 }
}

gallery_view.xml

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/about_bg"
android:orientation="vertical" >

<LinearLayout
    android:id="@+id/about_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:weightSum="1" >

    <LinearLayout
        android:id="@+id/about_layout1"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight=".4"
        android:orientation="vertical" >

        <ImageView
            android:id="@+id/view_image"
            android:layout_width="match_parent"
            android:layout_height="match_parent" 
            android:background="@drawable/about1">
     </ImageView>
    </LinearLayout>

    <LinearLayout
        android:id="@+id/about_layout2"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight=".6"
        android:orientation="vertical" >

        <TextView
            android:id="@+id/textView1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="SIGNATURE LANDMARK OF MALAYSIA-SINGAPORE CAUSEWAY"
            android:textColor="#000000"
            android:gravity="center"
            android:padding="18dp"
            android:textStyle="bold"
            android:textAppearance="?android:attr/textAppearance" />


        <ScrollView
            android:layout_width="fill_parent"
            android:layout_height="match_parent"
            android:fillViewport="false"
            android:orientation="vertical"
            android:scrollbars="none"
            android:layout_marginBottom="10dp"
            android:padding="10dp" >

            <TextView
                android:id="@+id/description"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:textColor="#000000"
                android:text="TextView" />

            </ScrollView>
    </LinearLayout>
 </LinearLayout>

How to escape regular expression special characters using javascript?

With \ you escape special characters

Escapes special characters to literal and literal characters to special.

E.g: /$s$/ matches '(s)' while /(\s)/ matches any whitespace and captures the match.

Source: http://www.javascriptkit.com/javatutors/redev2.shtml

How to use boost bind with a member function

Use the following instead:

boost::function<void (int)> f2( boost::bind( &myclass::fun2, this, _1 ) );

This forwards the first parameter passed to the function object to the function using place-holders - you have to tell Boost.Bind how to handle the parameters. With your expression it would try to interpret it as a member function taking no arguments.
See e.g. here or here for common usage patterns.

Note that VC8s cl.exe regularly crashes on Boost.Bind misuses - if in doubt use a test-case with gcc and you will probably get good hints like the template parameters Bind-internals were instantiated with if you read through the output.

Remove querystring from URL

A simple way is you can do as follows

public static String stripQueryStringAndHashFromPath(String uri) {
 return uri.replaceAll(("(\\?.*|\\#.*)"), "");
}

Passing a varchar full of comma delimited values to a SQL Server IN function

It's a very common question. Canned answer, several nice techniques:

http://www.sommarskog.se/arrays-in-sql-2005.html

How to set up Spark on Windows?

You can use following ways to setup Spark:

Building from Source
Using prebuilt release

Though there are various ways to build Spark from Source.
First I tried building Spark source with SBT but that requires hadoop. To avoid those issues, I used pre-built release.

Instead of Source,I downloaded Prebuilt release for hadoop 2.x version and ran it. For this you need to install Scala as prerequisite.

I have collated all steps here :
How to run Apache Spark on Windows7 in standalone mode

Hope it'll help you..!!!

How do I find the PublicKeyToken for a particular dll?

I use Windows Explorer, navigate to C:\Windows\assembly , find the one I need. From the Properties you can copy the PublicKeyToken.

This doesn't rely on Visual Studio or any other utilities being installed.

What is the difference between print and puts?

The API docs give some good hints:

print() ? nil

print(obj, ...) ? nil

Writes the given object(s) to ios. Returns nil.

The stream must be opened for writing. Each given object that isn't a string will be converted by calling its to_s method. When called without arguments, prints the contents of $_.

If the output field separator ($,) is not nil, it is inserted between objects. If the output record separator ($\) is not nil, it is appended to the output.

...

puts(obj, ...) ? nil

Writes the given object(s) to ios. Writes a newline after any that do not already end with a newline sequence. Returns nil.

The stream must be opened for writing. If called with an array argument, writes each element on a new line. Each given object that isn't a string or array will be converted by calling its to_s method. If called without arguments, outputs a single newline.

Experimenting a little with the points given above, the differences seem to be:

Called with multiple arguments, print separates them by the 'output field separator' $, (which defaults to nothing) while puts separates them by newlines. puts also puts a newline after the final argument, while print does not.

2.1.3 :001 > print 'hello', 'world'
helloworld => nil 
2.1.3 :002 > puts 'hello', 'world'
hello
world
 => nil
2.1.3 :003 > $, = 'fanodd'
 => "fanodd" 
2.1.3 :004 > print 'hello', 'world'
hellofanoddworld => nil 
2.1.3 :005 > puts 'hello', 'world'
hello
world
 => nil

puts automatically unpacks arrays, while print does not:

2.1.3 :001 > print [1, [2, 3]], [4]
[1, [2, 3]][4] => nil 
2.1.3 :002 > puts [1, [2, 3]], [4]
1
2
3
4
 => nil

print with no arguments prints $_ (the last thing read by gets), while puts prints a newline:

2.1.3 :001 > gets
hello world
 => "hello world\n" 
2.1.3 :002 > puts

 => nil 
2.1.3 :003 > print
hello world
 => nil

print writes the output record separator $\ after whatever it prints, while puts ignores this variable:

mark@lunchbox:~$ irb
2.1.3 :001 > $\ = 'MOOOOOOO!'
 => "MOOOOOOO!" 
2.1.3 :002 > puts "Oink! Baa! Cluck! "
Oink! Baa! Cluck! 
 => nil 
2.1.3 :003 > print "Oink! Baa! Cluck! "
Oink! Baa! Cluck! MOOOOOOO! => nil

Is Xamarin free in Visual Studio 2015?

I asked the same question to Xamarin support team, they replied with following:

You can develop an app with Xamarin for commercial usage - there is no extra charge! We only require you to comply with Visual Studio's licensing terms,

which means that in companies of less than 250 employees with less than $1million USD annual revenue, you may use Visual Studio completely free (including Xamarin) for up to 5 developers.

However after you pass those barriers, you would need a Visual Studio license (which includes Xamarin).

Refer the screenshot below.

Jackson enum Serializing and DeSerializer

Here is another example that uses string values instead of a map.

public enum Operator {
    EQUAL(new String[]{"=","==","==="}),
    NOT_EQUAL(new String[]{"!=","<>"}),
    LESS_THAN(new String[]{"<"}),
    LESS_THAN_EQUAL(new String[]{"<="}),
    GREATER_THAN(new String[]{">"}),
    GREATER_THAN_EQUAL(new String[]{">="}),
    EXISTS(new String[]{"not null", "exists"}),
    NOT_EXISTS(new String[]{"is null", "not exists"}),
    MATCH(new String[]{"match"});

    private String[] value;

    Operator(String[] value) {
        this.value = value;
    }

    @JsonValue
    public String toStringOperator(){
        return value[0];
    }

    @JsonCreator
    public static Operator fromStringOperator(String stringOperator) {
        if(stringOperator != null) {
            for(Operator operator : Operator.values()) {
                for(String operatorString : operator.value) {
                    if (stringOperator.equalsIgnoreCase(operatorString)) {
                        return operator;
                    }
                }
            }
        }
        return null;
    }
}

All com.android.support libraries must use the exact same version specification

Use support-v13 instead of support-v4

compile 'com.android.support:support-v13:25.2.0'

In Objective-C, how do I test the object type?

Simple, [yourobject class] it will return the class name of yourobject.

How to find Current open Cursors in Oracle

This could work:

SELECT    sql_text "SQL Query", 
          Count(*) AS "Open Cursors" 
FROM      v$open_cursor 
GROUP BY  sql_text 
HAVING    Count(*) > 2 
ORDER BY  Count(*) DESC;

What does the "__block" keyword mean?

It means that the variable it is a prefix to is available to be used within a block.

Stratified Train/Test-split in scikit-learn

#train_size is 1 - tst_size - vld_size
tst_size=0.15
vld_size=0.15

X_train_test, X_valid, y_train_test, y_valid = train_test_split(df.drop(y, axis=1), df.y, test_size = vld_size, random_state=13903) 

X_train_test_V=pd.DataFrame(X_train_test)
X_valid=pd.DataFrame(X_valid)

X_train, X_test, y_train, y_test = train_test_split(X_train_test, y_train_test, test_size=tst_size, random_state=13903)

jquery fill dropdown with json data

Here is an example of code, that attempts to featch AJAX data from /Ajax/_AjaxGetItemListHelp/ URL. Upon success, it removes all items from dropdown list with id = OfferTransModel_ItemID and then it fills it with new items based on AJAX call's result:

if (productgrpid != 0) {    
    $.ajax({
        type: "POST",
        url: "/Ajax/_AjaxGetItemListHelp/",
        data:{text:"sam",OfferTransModel_ItemGrpid:productgrpid},
        contentType: "application/json",              
        dataType: "json",
        success: function (data) {
            $("#OfferTransModel_ItemID").empty();

            $.each(data, function () {
                $("#OfferTransModel_ItemID").append($("<option>                                                      
                </option>").val(this['ITEMID']).html(this['ITEMDESC']));
            });
        }
    });
}

Returned AJAX result is expected to return data encoded as AJAX array, where each item contains ITEMID and ITEMDESC elements. For example:

{
    {
        "ITEMID":"13",
        "ITEMDESC":"About"
    },
    {
        "ITEMID":"21",
        "ITEMDESC":"Contact"
    }
}

The OfferTransModel_ItemID listbox is populated with above data and its code should look like:

<select id="OfferTransModel_ItemID" name="OfferTransModel[ItemID]">
    <option value="13">About</option>
    <option value="21">Contact</option>
</select>

When user selects About, form submits 13 as value for this field and 21 when user selects Contact and so on.

Fell free to modify above code if your server returns URL in a different format.

.htaccess: where is located when not in www base dir

. (dot) files are hidden by default on Unix/Linux systems. Most likely, if you know they are .htaccess files, then they are probably in the root folder for the website.

If you are using a command line (terminal) to access, then they will only show up if you use:

ls -a

If you are using a GUI application, look for a setting to "show hidden files" or something similar.

If you still have no luck, and you are on a terminal, you can execute these commands to search the whole system (may take some time):

cd /
find . -name ".htaccess"

This will list out any files it finds with that name.

wget: unable to resolve host address `http'

I figured out what went wrong. In the proxy configuration of my box, an extra http:// got prefixed to "proxy server with http".

Example..

http://http://proxy.mycollege.com

and that has created problems. Corrected that, and it works perfectly.

Thanks @WhiteCoffee and @ChrisBint for your suggestions!

Java method to sum any number of ints

import java.util.Scanner;

public class SumAll {
    public static void sumAll(int arr[]) {//initialize method return sum
        int sum = 0;
        for (int i = 0; i < arr.length; i++) {
            sum += arr[i];
        }
        System.out.println("Sum is : " + sum);
    }

    public static void main(String[] args) {
        int num;
        Scanner input = new Scanner(System.in);//create scanner object 
        System.out.print("How many # you want to add : ");
        num = input.nextInt();//return num from keyboard
        int[] arr2 = new int[num];
        for (int i = 0; i < arr2.length; i++) {
            System.out.print("Enter Num" + (i + 1) + ": ");
            arr2[i] = input.nextInt();
        }
        sumAll(arr2);
    }

}

How to get value at a specific index of array In JavaScript?

You can just use []:

var valueAtIndex1 = myValues[1];

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.)

Remove all line breaks from a long string of text

A method taking into consideration

additional white characters at the beginning/end of string
additional white characters at the beginning/end of every line
various end-line characters

it takes such a multi-line string which may be messy e.g.

test_str = '\nhej ho \n aaa\r\n   a\n '

and produces nice one-line string

>>> ' '.join([line.strip() for line in test_str.strip().splitlines()])
'hej ho aaa a'

UPDATE: To fix multiple new-line character producing redundant spaces:

' '.join([line.strip() for line in test_str.strip().splitlines() if line.strip()])

This works for the following too test_str = '\nhej ho \n aaa\r\n\n\n\n\n a\n '

Get Public URL for File - Google Cloud Storage - App Engine (Python)

You need to use get_serving_url from the Images API. As that page explains, you need to call create_gs_key() first to get the key to pass to the Images API.

Using form input to access camera and immediately upload photos using web app

It's really easy to do this, simply send the file via an XHR request inside of the file input's onchange handler.

<input id="myFileInput" type="file" accept="image/*;capture=camera">

var myInput = document.getElementById('myFileInput');

function sendPic() {
    var file = myInput.files[0];

    // Send file here either by adding it to a `FormData` object 
    // and sending that via XHR, or by simply passing the file into 
    // the `send` method of an XHR instance.
}

myInput.addEventListener('change', sendPic, false);

Read file from line 2 or skip header row

If you want the first line and then you want to perform some operation on file this code will helpful.

with open(filename , 'r') as f:
    first_line = f.readline()
    for line in f:
            # Perform some operations

git clone: Authentication failed for <URL>

In my case the error was some old username and password was stored in cache.

So I removed it by going to sourceTree and delete the existing account.

Now for the new clone then it will ask you for the password for the repo.

Uncaught SyntaxError: Unexpected token < On Chrome

It could be that the resource you're trying to request is under restricted access via your web app configuration, i.e. user must be logged for the application to serve the file.

Try adding this to your Web.Config file (this is for .NET applications):

<location path="js/resourcefile.js">
  <system.web>
    <authorization>
      <allow users="?" />
    </authorization>
  </system.web>
</location>

You can place it anywhere before the closing configuration tag.

How create Date Object with values in java

I think your date comes from php and is written to html (dom) or? I have a php-function to prep all dates and timestamps. This return a formation that is be needed.

$timeForJS = timeop($datetimeFromDatabase['payedon'], 'js', 'local'); // save 10/12/2016 09:20 on var

this format can be used on js to create new Date...

<html>
   <span id="test" data-date="<?php echo $timeForJS; ?>"></span>
   <script>var myDate = new Date( $('#test').attr('data-date') );</script>
</html>

What i will say is, make your a own function to wrap, that make your life easyr. You can us my func as sample but is included in my cms you can not 1 to 1 copy and paste :)

    function timeop($utcTime, $for, $tz_output = 'system')
{
    // echo "<br>Current time ( UTC ): ".$wwm->timeop('now', 'db', 'system');
    // echo "<br>Current time (USER): ".$wwm->timeop('now', 'db', 'local');
    // echo "<br>Current time (USER): ".$wwm->timeop('now', 'D d M Y H:i:s', 'local');
    // echo "<br>Current time with user lang (USER): ".$wwm->timeop('now', 'datetimes', 'local');

    // echo '<br><br>Calculator test is users timezone difference != 0! Tested with "2014-06-27 07:46:09"<br>';
    // echo "<br>Old time (USER -> UTC): ".$wwm->timeop('2014-06-27 07:46:09', 'db', 'system');
    // echo "<br>Old time (UTC -> USER): ".$wwm->timeop('2014-06-27 07:46:09', 'db', 'local');

    /** -- */
    // echo '<br><br>a Time from db if same with user time?<br>';
    // echo "<br>db-time (2019-06-27 07:46:09) time left = ".$wwm->timeleft('2019-06-27 07:46:09', 'max');
    // echo "<br>db-time (2014-06-27 07:46:09) time left = ".$wwm->timeleft('2014-06-27 07:46:09', 'max', 'txt');

    /** -- */
    // echo '<br><br>Calculator test with other formats<br>';
    // echo "<br>2014/06/27 07:46:09: ".$wwm->ntimeop('2014/06/27 07:46:09', 'db', 'system');

    switch($tz_output){
        case 'system':
            $tz = 'UTC';
            break;

        case 'local':
            $tz = $_SESSION['wwm']['sett']['tz'];
            break;

        default:
            $tz = $tz_output;
            break;
    }

    $date = new DateTime($utcTime,  new DateTimeZone($tz));

    if( $tz != 'UTC' ) // Only time converted into different time zone
    {
        // now check at first the difference in seconds
        $offset = $this->tz_offset($tz);
        if( $offset != 0 ){
            $calc = ( $offset >= 0  ) ? 'add' : 'sub';
            // $calc = ( ($_SESSION['wwm']['sett']['tzdiff'] >= 0 AND $tz_output == 'user') OR ($_SESSION['wwm']['sett']['tzdiff'] <= 0 AND $tz_output == 'local') ) ? 'sub' : 'add';
            $offset = ['math' => $calc, 'diff' => abs($offset)];
            $date->$offset['math']( new DateInterval('PT'.$offset['diff'].'S') ); // php >= 5.3 use add() or sub()
        }
    }

    // create a individual output
    switch( $for ){
        case 'js':
            $format = 'm/d/Y H:i'; // Timepicker use only this format m/d/Y H:i without seconds // Sett automatical seconds default to 00
            break;
        case 'js:s':
            $format = 'm/d/Y H:i:s'; // Timepicker use only this format m/d/Y H:i:s with Seconds
            break;
        case 'db':
            $format = 'Y-m-d H:i:s'; // Database use only this format Y-m-d H:i:s
            break;
        case 'date':
        case 'datetime':
        case 'datetimes':
            $format = wwmSystem::$languages[$_SESSION['wwm']['sett']['isolang']][$for.'_format']; // language spezific output
            break;
        default:
            $format = $for;
            break;
    }

    $output = $date->format( $format );

    /** Replacement
     * 
     * D = day short name
     * l = day long name
     * F = month long name
     * M = month short name
     */
    $output = str_replace([
        $date->format('D'),
        $date->format('l'),
        $date->format('F'),
        $date->format('M')
    ],[
        $this->trans('date', $date->format('D')),
        $this->trans('date', $date->format('l')),
        $this->trans('date', $date->format('F')),
        $this->trans('date', $date->format('M'))
    ], $output);

    return $output; // $output->getTimestamp();
}

Copy directory to another directory using ADD command

ADD go /usr/local/

will copy the contents of your local go directory in the /usr/local/ directory of your docker image.

To copy the go directory itself in /usr/local/ use:

ADD go /usr/local/go

COPY go /usr/local/go

Where is the default log location for SharePoint/MOSS?

SharePoint uses a lot of different logging mechanisms. Most importantly you can configure the location of the logs through Central Admin. To give you an understanding of the logs involved, here is a quote from http://raiumair.wordpress.com/2007/06/19/quick-a-to-z-of-sharepoint-logs/

All file based logs can be read by text editors and can be parsed by using popular log parsing tools (Log Parser 2.2 from Microsoft or Funnel Web). It will also be a good idea to read the IIS Logs which are generally saved at (System Drive):\WINDOWS\system32\LogFiles

a) Diagnostics Logs

· Event Throttling Logs – These end up going to the Windows Event Log and can be viewed in the Event Viewer. They show Errors and Warnings.

· Trace Logs – These show detailed line by line tracing infomration emitted during a web request or service execution. They end up being stored at a known location on the front-end server. Default Location: (System Drive):\Program Files\Common Files\Microsoft Shared\Web Server Extensions\12\LOGS\

b) Audit Logs - They end up in the associated Content Database tables and can be viewed at Site Collection Level as well as Site Level using the web browser. WSS 3.0 and MOSS 2007 use different pages to show Audit Log Reports.

c) Usage Logs – They get stored locally on the front-end servers and get processed both locally and at farm level via SSP (this is based on the setup as I understand the results from the local processing are merged by SSP) and can be viewed at both the Site Level and Site Collection Level. Default Location: (System Drive):\Program Files\Common Files\Microsoft Shared\Web Server Extensions\12\Logs

d) Search\Query Logs – These are saved in the associated SSP database but can be viewed at SSP level via the Web Browser and in MOSS at Site Collection Level by going to the settings page.

e) Information Management Logs – Stored in the associated Content Database and can be can be viewed at the Site Collection Level.

f) Content and Structure Logs – This option is only available after one enables the publication feature. This store is saved in the Content Database associated with the Site Collection and can be viewed at Site Collection level by going to the settings page.

Add image in title bar

you should be searching about how to add favicon.ico . You can try adding favicon.ico directly in your html pages like this

<link rel="shortcut icon" href="/favicon.png" type="image/png">
<link rel="shortcut icon" type="image/png" href="http://www.example.com/favicon.png" />

Or you can update that in your webserver. It is advised to add in your webserver as you don't need to add this in each of your html pages (assuming no includes).

To add in your apache place the favicon.ico in your root website director and add this in httpd.conf

AddType image/x-icon .ico

Check if $_POST exists

The proper way of checking if array key exists is function array_key_exists()

The difference is that when you have $_POST['variable'] = null it means that key exists and was send but value was null

The other option is isset() which which will check if array key exists and if it was set

The last option is to use empty() which will check if array key exists if is set and if value is not considered empty.

Examples:

$arr = [
  'a' => null,
  'b' => '',
  'c' => 1
];

array_key_exists('a', $arr); // true
isset($arr['a']); // false
empty($arr['a']); // true


array_key_exists('b', $arr); // true
isset($arr['b']); // true
empty($arr['b']); // true


array_key_exists('c', $arr); // true
isset($arr['c']); // true
empty($arr['c']); // false

Regarding your question

The proper way to check if value was send is to use array_key_exists() with check of request method

if ($_SERVER['REQUEST_METHOD'] == 'POST' && array_key_exists('fromPerson', $_POST)    
{
   // logic
}

But there are some cases depends on your logic where isset() and empty() can be good as well.

How to Serialize a list in java?

List is just an interface. The question is: is your actual List implementation serializable? Speaking about the standard List implementations (ArrayList, LinkedList) from the Java run-time, most of them actually are already.

LEFT INNER JOIN vs. LEFT OUTER JOIN - Why does the OUTER take longer?

The fact that the same number of rows is returned is an after fact, the query optimizer cannot know in advance that every row in Accepts has a matching row in Marker, can it?

If you join two tables A and B, say A has 1 million rows and B has 1 row. If you say A LEFT INNER JOIN B it means only rows that match both A and B can result, so the query plan is free to scan B first, then use an index to do a range scan in A, and perhaps return 10 rows. But if you say A LEFT OUTER JOIN B then at least all rows in A have to be returned, so the plan must scan everything in A no matter what it finds in B. By using an OUTER join you are eliminating one possible optimization.

If you do know that every row in Accepts will have a match in Marker, then why not declare a foreign key to enforce this? The optimizer will see the constraint, and if is trusted, will take it into account in the plan.

SQL server stored procedure return a table

You can use an out parameter instead of the return value if you want both a result set and a return value

CREATE PROCEDURE proc_name 
@param int out
AS
BEGIN
    SET @param = value
SELECT ... FROM [Table] WHERE Condition
END
GO

Updating the value of data attribute using jQuery

I want to change the width and height of a div. data attributes did not change it. Instead I use:

var size = $("#theme_photo_size").val().split("x");
$("#imageupload_img").width(size[0]);
$("#imageupload_img").attr("data-width", size[0]);
$("#imageupload_img").height(size[1]);
$("#imageupload_img").attr("data-height", size[1]);

be careful:

$("#imageupload_img").data("height", size[1]); //did not work

did not set it

$("#imageupload_img").attr("data-height", size[1]); // yes it worked!

this has set it.

Access-Control-Allow-Origin Multiple Origin Domains?

Maybe I am wrong, but as far as I can see Access-Control-Allow-Origin has an "origin-list" as parameter.

By definition an origin-list is:

origin            = "origin" ":" 1*WSP [ "null" / origin-list ]
origin-list       = serialized-origin *( 1*WSP serialized-origin )
serialized-origin = scheme "://" host [ ":" port ]
                  ; <scheme>, <host>, <port> productions from RFC3986

And from this, I argue different origins are admitted and should be space separated.

trigger body click with jQuery

I've used the following code a few times and it works sweet:

$("body").click(function(e){ 
    // Check what has been clicked:
    var target = $(e.target); 
    if(target.is("#target")){
    // The target was clicked
    // Do something...
  }
});

How to use SVG markers in Google Maps API v3

Yes you can use an .svg file for the icon just like you can .png or another image file format. Just set the url of the icon to the directory where the .svg file is located. For example:

var icon = {
        url: 'path/to/images/car.svg',
        size: new google.maps.Size(sizeX, sizeY),
        origin: new google.maps.Point(0, 0),
        anchor: new google.maps.Point(sizeX/2, sizeY/2)
};

var marker = new google.maps.Marker({
        position: event.latLng,
        map: map,
        draggable: false,
        icon: icon
});

Checking Maven Version

i faced with similar issue when i first installed it. It worked when i added user variable name- PATH and variable value- C:\Program Files\apache-maven-3.5.3\bin

variable value should direct to "bin" folder. finally check with cmd (mvn -v) in a new cmd prompt. Good Luck :)

How to calculate number of days between two dates

Try this Using moment.js (Its quite easy to compute date operations in javascript)

firstDate.diff(secondDate, 'days', false);// true|false for fraction value

Result will give you number of days in integer.

libpthread.so.0: error adding symbols: DSO missing from command line

The same thing happened to me as I was installing the HPCC benchmark (includes HPL and a few other benchmarks). I added -lm to the compiler flags in my build script and then it successfully compiled.

How to create JSON Object using String?

If you use the gson.JsonObject you can have something like that:

import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

String jsonString = "{'test1':'value1','test2':{'id':0,'name':'testName'}}"
JsonObject jsonObject = (JsonObject) jsonParser.parse(jsonString)

What is hashCode used for? Is it unique?

After learning what it is all about, I thought to write a hopefully simpler explanation via analogy:

Summary: What is a hashcode?

It's a fingerprint. We can use this finger print to identify people of interest.

Read below for more details:

Think of a Hashcode as us trying to To Uniquely Identify Someone

I am a detective, on the look out for a criminal. Let us call him Mr Cruel. (He was a notorious murderer when I was a kid -- he broke into a house kidnapped and murdered a poor girl, dumped her body and he's still out on the loose - but that's a separate matter). Mr Cruel has certain peculiar characteristics that I can use to uniquely identify him amongst a sea of people. We have 25 million people in Australia. One of them is Mr Cruel. How can we find him?

Bad ways of Identifying Mr Cruel

Apparently Mr Cruel has blue eyes. That's not much help because almost half the population in Australia also has blue eyes.

Good ways of Identifying Mr Cruel

What else can i use? I know: I will use a fingerprint!

Advantages:

It is really really hard for two people to have the same finger print (not impossible, but extremely unlikely).
Mr Cruel's fingerprint will never change.
Every single part of Mr Cruel's entire being: his looks, hair colour, personality, eating habits etc must (ideally) be reflected in his fingerprint, such that if he has a brother (who is very similar but not the same) - then both should have different finger prints. I say "should" because we cannot guarantee 100% that two people in this world will have different fingerprints.
But we can always guarantee that Mr Cruel will always have the same finger print - and that his fingerprint will NEVER change.

The above characteristics generally make for good hash functions.

So what's the deal with 'Collisions'?

So imagine if I get a lead and I find someone matching Mr Cruel's fingerprints. Does this mean I have found Mr Cruel?

........perhaps! I must take a closer look. If i am using SHA256 (a hashing function) and I am looking in a small town with only 5 people - then there is a very good chance I found him! But if I am using MD5 (another famous hashing function) and checking for fingerprints in a town with +2^1000 people, then it is a fairly good possibility that two entirely different people might have the same fingerprint.

So what is the benefit of all this anyways?

The only real benefit of hashcodes is if you want to put something in a hash table - and with hash tables you'd want to find objects quickly - and that's where the hash code comes in. They allow you to find things in hash tables really quickly. It's a hack that massively improves performance, but at a small expense of accuracy.

So let's imagine we have a hash table filled with people - 25 million suspects in Australia. Mr Cruel is somewhere in there..... How can we find him really quickly? We need to sort through them all: to find a potential match, or to otherwise acquit potential suspects. You don't want to consider each person's unique characteristics because that would take too much time. What would you use instead? You'd use a hashcode! A hashcode can tell you if two people are different. Whether Joe Bloggs is NOT Mr Cruel. If the prints don't match then you know it's definitely NOT Mr Cruel. But, if the finger prints do match then depending on the hash function you used, chances are already fairly good you found your man. But it's not 100%. The only way you can be certain is to investigate further: (i) did he/she have an opportunity/motive, (ii) witnesses etc etc.

When you are using computers if two objects have the same hash code value, then you again need to investigate further whether they are truly equal. e.g. You'd have to check whether the objects have e.g. the same height, same weight etc, if the integers are the same, or if the customer_id is a match, and then come to the conclusion whether they are the same. this is typically done perhaps by implementing an IComparer or IEquality interfaces.

Key Summary

So basically a hashcode is a finger print.

Two different people/objects can theoretically still have the same fingerprint. Or in other words. If you have two fingerprints that are the same.........then they need not both come from the same person/object.
Buuuuuut, the same person/object will always return the same fingerprint.
Which means that if two objects return different hash codes then you know for 100% certainty that those objects are different.

It takes a good 3 minutes to get your head around the above. Perhaps read it a few times till it makes sense. I hope this helps someone because it took a lot of grief for me to learn it all!

wget command to download a file and save as a different filename

Using CentOS Linux I found that the easiest syntax would be:

wget "link" -O file.ext

where "link" is the web address you want to save and "file.ext" is the filename and extension of your choice.

lambda expression join multiple tables with select and where clause

If I understand your questions correctly, all you need to do is add the .Where(m => m.r.u.UserId == 1):

    var UserInRole = db.UserProfiles.
        Join(db.UsersInRoles, u => u.UserId, uir => uir.UserId,
        (u, uir) => new { u, uir }).
        Join(db.Roles, r => r.uir.RoleId, ro => ro.RoleId, (r, ro) => new { r, ro })
        .Where(m => m.r.u.UserId == 1)
        .Select (m => new AddUserToRole
        {
            UserName = m.r.u.UserName,
            RoleName = m.ro.RoleName
        });

Hope that helps.

Why can't radio buttons be "readonly"?

Radio buttons would only need to be read-only if there are other options. If you don't have any other options, a checked radio button cannot be unchecked. If you have other options, you can prevent the user from changing the value merely by disabling the other options:

<input type="radio" name="foo" value="Y" checked>
<input type="radio" name="foo" value="N" disabled>

Fiddle: http://jsfiddle.net/qqVGu/

How to show what a commit did?

The answers by Bomber and Jakub (Thanks!) are correct and work for me in different situations.

For a quick glance at what was in the commit, I use

git show <replace this with your commit-id>

But I like to view a graphical Diff when studying something in detail and have set up a P4diff as my git diff and then use

git diff <replace this with your commit-id>^!

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