Programs & Examples On #Amazon ecs

Amazon Elastic Container Service (ECS) is a highly scalable, high performance container management service that supports Docker containers and allows you to easily run distributed applications on a managed cluster of Amazon EC2 instances.

How to identify which columns are not "NA" per row in a matrix?

Try:

which( !is.na(p), arr.ind=TRUE)

Which I think is just as informative and probably more useful than the output you specified, But if you really wanted the list version, then this could be used:

> apply(p, 1, function(x) which(!is.na(x)) )
[[1]]
[1] 2 3

[[2]]
[1] 4 7

[[3]]
integer(0)

[[4]]
[1] 5

[[5]]
integer(0)

Or even with smushing together with paste:

lapply(apply(p, 1, function(x) which(!is.na(x)) ) , paste, collapse=", ")

The output from which function the suggested method delivers the row and column of non-zero (TRUE) locations of logical tests:

> which( !is.na(p), arr.ind=TRUE)
     row col
[1,]   1   2
[2,]   1   3
[3,]   2   4
[4,]   4   5
[5,]   2   7

Without the arr.ind parameter set to non-default TRUE, you only get the "vector location" determined using the column major ordering the R has as its convention. R-matrices are just "folded vectors".

> which( !is.na(p) )
[1]  6 11 17 24 32

Changing tab bar item image and text color iOS

Try add it on AppDelegate.swift (inside application method):

UITabBar.appearance().tintColor = UIColor(red: 0/255.0, green: 0/255.0, blue: 0/255.0, alpha: 1.0)

// For WHITE color: 
UITabBar.appearance().tintColor = UIColor(red: 255/255.0, green: 255/255.0, blue: 255/255.0, alpha: 1.0)

Example:

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    // Tab bar icon selected color
    UITabBar.appearance().tintColor = UIColor(red: 0/255.0, green: 0/255.0, blue: 0/255.0, alpha: 1.0)
    // For WHITE color: UITabBar.appearance().tintColor = UIColor(red: 255/255.0, green: 255/255.0, blue: 255/255.0, alpha: 1.0)
    return true
}

Example:

enter image description here

enter image description here

My english is so bad! I'm sorry! :-)

How to find current transaction level?

SELECT CASE  
          WHEN transaction_isolation_level = 1 
             THEN 'READ UNCOMMITTED' 
          WHEN transaction_isolation_level = 2 
               AND is_read_committed_snapshot_on = 1 
             THEN 'READ COMMITTED SNAPSHOT' 
          WHEN transaction_isolation_level = 2 
               AND is_read_committed_snapshot_on = 0 THEN 'READ COMMITTED' 
          WHEN transaction_isolation_level = 3 
             THEN 'REPEATABLE READ' 
          WHEN transaction_isolation_level = 4 
             THEN 'SERIALIZABLE' 
          WHEN transaction_isolation_level = 5 
             THEN 'SNAPSHOT' 
          ELSE NULL
       END AS TRANSACTION_ISOLATION_LEVEL 
FROM   sys.dm_exec_sessions AS s
       CROSS JOIN sys.databases AS d
WHERE  session_id = @@SPID
  AND  d.database_id = DB_ID();

how to solve Error cannot add duplicate collection entry of type add with unique key attribute 'value' in iis 7

Just keep the following in mind.

In IIS if you have a folder for example called Pages with multiple websites in it. Website will inherit settings from the web.config file from the parent directory. So even if the folder page (in this example Pages) isn't a website but contains a web.config file, all websites listed inside of it will inherit the setting.

How to get status code from webclient?

Tried it out. ResponseHeaders do not include status code.

If I'm not mistaken, WebClient is capable of abstracting away multiple distinct requests in a single method call (e.g. correctly handling 100 Continue responses, redirects, and the like). I suspect that without using HttpWebRequest and HttpWebResponse, a distinct status code may not be available.

It occurs to me that, if you are not interested in intermediate status codes, you can safely assume the final status code is in the 2xx (successful) range, otherwise, the call would not be successful.

The status code unfortunately isn't present in the ResponseHeaders dictionary.

Google Text-To-Speech API

Go to console.developer.google.com login and get an API key or use microsoft bing's API
https://msdn.microsoft.com/en-us/library/?f=255&MSPPError=-2147217396

or even better use AT&T's speech API developer.att.com(paid one)
For voice recognition

Public Class Voice_recognition

    Public Function convertTotext(ByVal path As String, ByVal output As String) As String
        Dim request As HttpWebRequest = DirectCast(HttpWebRequest.Create("https://www.google.com/speech-api/v1/recognize?xjerr=1&client=speech2text&lang=en-US&maxresults=10"), HttpWebRequest)
        'path = Application.StartupPath & "curinputtmp.mp3"
        request.Timeout = 60000
        request.Method = "POST"
        request.KeepAlive = True
        request.ContentType = "audio/x-flac; rate=8000"  
        request.UserAgent = "speech2text"

        Dim fInfo As New FileInfo(path)
        Dim numBytes As Long = fInfo.Length
        Dim data As Byte()

        Using fStream As New FileStream(path, FileMode.Open, FileAccess.Read)
            data = New Byte(CInt(fStream.Length - 1)) {}
            fStream.Read(data, 0, CInt(fStream.Length))
            fStream.Close()
        End Using

        Using wrStream As Stream = request.GetRequestStream()
            wrStream.Write(data, 0, data.Length)
        End Using

        Try
            Dim response As HttpWebResponse = DirectCast(request.GetResponse(), HttpWebResponse)
            Dim resp = response.GetResponseStream()

            If resp IsNot Nothing Then
                Dim sr As New StreamReader(resp)
                MessageBox.Show(sr.ReadToEnd())

                resp.Close()
                resp.Dispose()
            End If
        Catch ex As System.Exception
            MessageBox.Show(ex.Message)
        End Try

        Return 0
    End Function
End Class

And for text to speech: use this.

I think you'll understand this
if didn't then use vbscript to vb/C# converter.
still didn't then contact Me.

I have done this before ,can't find the code now that this why i'm not directly givin' you the code.

Selenium WebDriver can't find element by link text

find_elements_by_xpath("//*[@class='class name']")

is a great solution

Execute ssh with password authentication via windows command prompt

The sshpass utility is meant for exactly this. First, install sshpass by typing this command:

sudo apt-get install sshpass

Then prepend your ssh/scp command with

sshpass -p '<password>' <ssh/scp command>

This program is easiest to install when using Linux.

User should consider using SSH's more secure public key authentication (with the ssh command) instead.

How do I get the Session Object in Spring?

Your friend here is org.springframework.web.context.request.RequestContextHolder

// example usage
public static HttpSession session() {
    ServletRequestAttributes attr = (ServletRequestAttributes) RequestContextHolder.currentRequestAttributes();
    return attr.getRequest().getSession(true); // true == allow create
}

This will be populated by the standard spring mvc dispatch servlet, but if you are using a different web framework you have add org.springframework.web.filter.RequestContextFilter as a filter in your web.xml to manage the holder.

EDIT: just as a side issue what are you actually trying to do, I'm not sure you should need access to the HttpSession in the retieveUser method of a UserDetailsService. Spring security will put the UserDetails object in the session for you any how. It can be retrieved by accessing the SecurityContextHolder:

public static UserDetails currentUserDetails(){
    SecurityContext securityContext = SecurityContextHolder.getContext();
    Authentication authentication = securityContext.getAuthentication();
    if (authentication != null) {
        Object principal = authentication.getPrincipal();
        return principal instanceof UserDetails ? (UserDetails) principal : null;
    }
    return null;
}

Need a row count after SELECT statement: what's the optimal SQL approach?

If you're using SQL Server, after your query you can select the @@RowCount function (or if your result set might have more than 2 billion rows use the RowCount_Big() function). This will return the number of rows selected by the previous statement or number of rows affected by an insert/update/delete statement.

SELECT my_table.my_col
  FROM my_table
 WHERE my_table.foo = 'bar'

SELECT @@Rowcount

Or if you want to row count included in the result sent similar to Approach #2, you can use the the OVER clause.

SELECT my_table.my_col,
    count(*) OVER(PARTITION BY my_table.foo) AS 'Count'
  FROM my_table
 WHERE my_table.foo = 'bar'

Using the OVER clause will have much better performance than using a subquery to get the row count. Using the @@RowCount will have the best performance because the there won't be any query cost for the select @@RowCount statement

Update in response to comment: The example I gave would give the # of rows in partition - defined in this case by "PARTITION BY my_table.foo". The value of the column in each row is the # of rows with the same value of my_table.foo. Since your example query had the clause "WHERE my_table.foo = 'bar'", all rows in the resultset will have the same value of my_table.foo and therefore the value in the column will be the same for all rows and equal (in this case) this the # of rows in the query.

Here is a better/simpler example of how to include a column in each row that is the total # of rows in the resultset. Simply remove the optional Partition By clause.

SELECT my_table.my_col, count(*) OVER() AS 'Count'
  FROM my_table
 WHERE my_table.foo = 'bar'

Efficiently getting all divisors of a given number

There is no efficient way in the sense of algorithmic complexity (an algorithm with polynomial complexity) known in science by now. So iterating until the square root as already suggested is mostly as good as you can be.

Mainly because of this, a large part of the currently used cryptography is based on the assumption that it is very time consuming to compute a prime factorization of any given integer.

GIT fatal: ambiguous argument 'HEAD': unknown revision or path not in the working tree

Jacob Helwig mentions in his answer that:

It looks like rev-parse is being used without sufficient error checking before-hand

Commit 62f162f from Jeff King (peff) should improve the robustness of git rev-parse in Git 1.9/2.0 (Q1 2014) (in addition of commit 1418567):

For cases where we do not match (e.g., "doesnotexist..HEAD"), we would then want to try to treat the argument as a filename.
try_difference() gets this right, and always unmunges in this case.
However, try_parent_shorthand() never unmunges, leading to incorrect error messages, or even incorrect results:

$ git rev-parse foobar^@
foobar
fatal: ambiguous argument 'foobar': unknown revision or path not in the working tree.
Use '--' to separate paths from revisions, like this:
'git <command> [<revision>...] -- [<file>...]'

android splash screen sizes for ldpi,mdpi, hdpi, xhdpi displays ? - eg : 1024X768 pixels for ldpi

For Android Mobile Devices

LDPI- icon-36x36, splash-426x320 (now with correct values)


MDPI- icon-48x48, splash-470x320


HDPI- icon 72x72, splash- 640x480


XHDPI- icon-96x96, splash- 960x720


XXHDPI- icon- 144x144

All in pixels.

For Android Tablet Devices

LDPI:
    Portrait: 200x320px
    Landscape: 320x200px
MDPI:
    Portrait: 320x480px
    Landscape: 480x320px
HDPI:
    Portrait: 480x800px
    Landscape: 800x480px
XHDPI:
    Portrait: 720px1280px
    Landscape: 1280x720px

How do I duplicate a line or selection within Visual Studio Code?

Note that for Ubuntu users (<= 17.4), Unity uses CTRL + ALT + SHIFT + Arrow Key for moving programs across virtual workspaces, which conflicts with the VS Code shortcuts. You'll need to rebind editor.action.copyLinesDownAction and editor.action.copyLinesUpAction to avoid the conflict (or change your workspace keybindings).

For Ubuntu 17.10+ that uses GNOME, it seems that GNOME does not use this keybinding in the same way according to its documentation, though if someone using vanilla workspaces on 17.10 can confirm this, it might be helpful for future answer seekers.

Eclipse not recognizing JVM 1.8

OK, so I don't really know what the problem was, but I simply fixed it by navigating to here http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html and installing 8u74 instead of 8u73 which is what I was prompted to do when I would go to "download latest version" in Java. So changing the versions is what did it in the end. Eclipse launched fine, now. Thanks for everyone's help!

edit: Apr 2018- Now is 8u161 and 8u162 (Just need one, I used 8u162 and it worked.)

Make an existing Git branch track a remote branch?

Here, using github and git version 2.1.4, just do:

$ git clone [email protected]:user/repo.git

And remotes come by itelsef, even if not linked locally:

$ git remote show origin

* remote origin
  Fetch URL: [email protected]:user/repo.git
  Push  URL: [email protected]:user/repo.git
  HEAD branch: master
  Remote branches:
    develop tracked         <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
    master  tracked
  Local branch configured for 'git pull':
    master merges with remote master
  Local ref configured for 'git push':
    master pushes to master (up to date)

But of course, still no local branch:

$ git branch
* master                  <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

See? Now if you just checkout develp, it will do the magic automatically:

$ git checkout develop
Branch develop set up to track remote branch develop from origin.
Switched to a new branch 'develop'

So easy!


Summary. Just run this 2 commands:

$ git clone [email protected]:user/repo.git
$ git checkout develop

LINQ: Select where object does not contain items from list

dump this into a more specific collection of just the ids you don't want

var notTheseBarIds = filterBars.Select(fb => fb.BarId);

then try this:

fooSelect = (from f in fooBunch
             where !notTheseBarIds.Contains(f.BarId)
             select f).ToList();

or this:

fooSelect = fooBunch.Where(f => !notTheseBarIds.Contains(f.BarId)).ToList();

Retrieving subfolders names in S3 bucket from boto3

It took me a lot of time to figure out, but finally here is a simple way to list contents of a subfolder in S3 bucket using boto3. Hope it helps

prefix = "folderone/foldertwo/"
s3 = boto3.resource('s3')
bucket = s3.Bucket(name="bucket_name_here")
FilesNotFound = True
for obj in bucket.objects.filter(Prefix=prefix):
     print('{0}:{1}'.format(bucket.name, obj.key))
     FilesNotFound = False
if FilesNotFound:
     print("ALERT", "No file in {0}/{1}".format(bucket, prefix))

Simple way to read single record from MySQL

The easiest way is to use mysql_result. I copied some of the code below from other answers to save time.

$link = mysql_connect('localhost','root','yourPassword')
mysql_select_db('database',$link);
$sql = 'SELECT id FROM games'
$result = mysql_query($sql,$link);

$num_rows = mysql_num_rows($result);

// i is the row number and will be 0 through $num_rows-1
for ($i = 0; $i < $num_rows; $i++) {
    $value = mysql_result($result, i, 'id');
    echo 'Row ', i, ': ', $value, "\n";
}

Shell script to set environment variables

Please show us more parts of the script and tell us what commands you had to individually execute and want to simply.

Meanwhile you have to use double quotes not single quote to expand variables:

export PATH="/home/linux/Practise/linux-devkit/bin/:$PATH"

Semicolons at the end of a single command are also unnecessary.

So far:

#!/bin/sh
echo "Perform Operation in su mode"
export ARCH=arm
echo "Export ARCH=arm Executed"
export PATH="/home/linux/Practise/linux-devkit/bin/:$PATH"
echo "Export path done"
export CROSS_COMPILE='/home/linux/Practise/linux-devkit/bin/arm-arago-linux-gnueabi-' ## What's next to -?
echo "Export CROSS_COMPILE done"
# continue your compilation commands here
...

For su you can run it with:

su -c 'sh /path/to/script.sh'

Note: The OP was not explicitly asking for steps on how to create export variables in an interactive shell using a shell script. He only asked his script to be assessed at most. He didn't mention details on how his script would be used. It could have been by using . or source from the interactive shell. It could have been a standalone scipt, or it could have been source'd from another script. Environment variables are not specific to interactive shells. This answer solved his problem.

JS: Uncaught TypeError: object is not a function (onclick)

Please change only the name of the function; no other change is required

<script>
    function totalbandwidthresult() {
        alert("fdf");
        var fps = Number(document.calculator.fps.value);
        var bitrate = Number(document.calculator.bitrate.value);
        var numberofcameras = Number(document.calculator.numberofcameras.value);
        var encoding = document.calculator.encoding.value;
        if (encoding = "mjpeg") {
            storage = bitrate * fps;
        } else {
            storage = bitrate;
        }

        totalbandwidth = (numberofcameras * storage) / 1000;
        alert(totalbandwidth);
        document.calculator.totalbandwidthresult.value = totalbandwidth;
    }
</script>

<form name="calculator" class="formtable">
    <div class="formrow">
        <label for="rcname">RC Name</label>
        <input type="text" name="rcname">
    </div>
    <div class="formrow">
        <label for="fps">FPS</label>
        <input type="text" name="fps">
    </div>
    <div class="formrow">
        <label for="bitrate">Bitrate</label>
        <input type="text" name="bitrate">
    </div>
    <div class="formrow">
        <label for="numberofcameras">Number of Cameras</label>
        <input type="text" name="numberofcameras">
    </div>
    <div class="formrow">
        <label for="encoding">Encoding</label>
        <select name="encoding" id="encodingoptions">
            <option value="h264">H.264</option>
            <option value="mjpeg">MJPEG</option>
            <option value="mpeg4">MPEG4</option>
        </select>
    </div>Total Storage:
    <input type="text" name="totalstorage">Total Bandwidth:
    <input type="text" name="totalbandwidth">
    <input type="button" value="totalbandwidthresult" onclick="totalbandwidthresult();">
</form>

Conveniently map between enum and int / String

I found this on the web, it was very helpful and simple to implement. This solution was NOT made by me

http://www.ajaxonomy.com/2007/java/making-the-most-of-java-50-enum-tricks

public enum Status {
 WAITING(0),
 READY(1),
 SKIPPED(-1),
 COMPLETED(5);

 private static final Map<Integer,Status> lookup 
      = new HashMap<Integer,Status>();

 static {
      for(Status s : EnumSet.allOf(Status.class))
           lookup.put(s.getCode(), s);
 }

 private int code;

 private Status(int code) {
      this.code = code;
 }

 public int getCode() { return code; }

 public static Status get(int code) { 
      return lookup.get(code); 
 }

}

PHP mail not working for some reason

For HostGator, you need to use the following for your headers:

$headers = 'From: [email protected]' . " " .
'Reply-To: [email protected]' . " " .
'X-Mailer: PHP/' . phpversion();

It only worked for me when the from user was host e-mail while the Reply-To can be something different e.g. From: [email protected], Reply-To: [email protected]

http://support.hostgator.com/articles/specialized-help/technical/php-email-from-header http://support.hostgator.com/articles/specialized-help/technical/how-to-use-sendmail-with-php

nodeJS - How to create and read session with express

I need to point out here that you're incorrectly adding middleware to the application. The app.use calls should not be done within the app.get request handler, but outside of it. Simply call them directly after createServer, or take a look at the other examples in the docs.

The secret you pass to express.session should be a string constant, or perhaps something taken from a configuration file. Don't feed it something the client might know, that's actually dangerous. It's a secret only the server should know about.

If you want to store the email address in the session, simply do something along the lines of:

req.session.email = req.param('email');

With that out of the way...


If I understand correctly, what you're trying to do is handle one or more HTTP requests and keep track of a session, then later on open a Socket.IO connection from which you need the session data as well.

What's tricky about this problem is that Socket.IO's means of making the magic work on any http.Server is by hijacking the request event. Thus, Express' (or rather Connect's) session middleware is never called on the Socket.IO connection.

I believe you can make this work, though, with some trickery.

You can get to Connect's session data; you simply need to get a reference to the session store. The easiest way to do that is to create the store yourself before calling express.session:

// A MemoryStore is the default, but you probably want something
// more robust for production use.
var store = new express.session.MemoryStore;
app.use(express.session({ secret: 'whatever', store: store }));

Every session store has a get(sid, callback) method. The sid parameter, or session ID, is stored in a cookie on the client. The default name of that cookie is connect.sid. (But you can give it any name by specifying a key option in your express.session call.)

Then, you need to access that cookie on the Socket.IO connection. Unfortunately, Socket.IO doesn't seem to give you access to the http.ServerRequest. A simple work around would be to fetch the cookie in the browser, and send it over the Socket.IO connection.

Code on the server would then look something like the following:

var io      = require('socket.io'),
    express = require('express');

var app    = express.createServer(),
    socket = io.listen(app),
    store  = new express.session.MemoryStore;
app.use(express.cookieParser());
app.use(express.session({ secret: 'something', store: store }));

app.get('/', function(req, res) {
  var old = req.session.email;
  req.session.email = req.param('email');

  res.header('Content-Type', 'text/plain');
  res.send("Email was '" + old + "', now is '" + req.session.email + "'.");
});

socket.on('connection', function(client) {
  // We declare that the first message contains the SID.
  // This is where we handle the first message.
  client.once('message', function(sid) {
    store.get(sid, function(err, session) {
      if (err || !session) {
        // Do some error handling, bail.
        return;
      }

      // Any messages following are your chat messages.
      client.on('message', function(message) {
        if (message.email === session.email) {
          socket.broadcast(message.text);
        }
      });
    });
  });
});

app.listen(4000);

This assumes you only want to read an existing session. You cannot actually create or delete sessions, because Socket.IO connections may not have a HTTP response to send the Set-Cookie header in (think WebSockets).

If you want to edit sessions, that may work with some session stores. A CookieStore wouldn't work for example, because it also needs to send a Set-Cookie header, which it can't. But for other stores, you could try calling the set(sid, data, callback) method and see what happens.

SQL grammar for SELECT MIN(DATE)

To get the titles for dates greater than a week ago today, use this:

SELECT title, MIN(date_key_no) AS intro_date FROM table HAVING MIN(date_key_no)>= TO_NUMBER(TO_CHAR(SysDate, 'YYYYMMDD')) - 7

Get clicked item and its position in RecyclerView

From the designer, you can set the onClick property of the listItem to a method defined with a single parameter. I have an example method defined below. The method getAdapterPosition will give you the index of the selected listItem.

public void exampleOnClickMethod(View view){
    myRecyclerView.getChildViewHolder(view).getAdapterPosition());
}

For information on setting up a RecyclerView, see the documentation here: https://developer.android.com/guide/topics/ui/layout/recyclerview

Is it possible to convert char[] to char* in C?

Well, I'm not sure to understand your question...

In C, Char[] and Char* are the same thing.

Edit : thanks for this interesting link.

Java: How to set Precision for double value?

BigDecimal value = new BigDecimal(10.0000);
value.setScale(4);

Byte Array in Python

In Python 3, we use the bytes object, also known as str in Python 2.

# Python 3
key = bytes([0x13, 0x00, 0x00, 0x00, 0x08, 0x00])

# Python 2
key = ''.join(chr(x) for x in [0x13, 0x00, 0x00, 0x00, 0x08, 0x00])

I find it more convenient to use the base64 module...

# Python 3
key = base64.b16decode(b'130000000800')

# Python 2
key = base64.b16decode('130000000800')

You can also use literals...

# Python 3
key = b'\x13\0\0\0\x08\0'

# Python 2
key = '\x13\0\0\0\x08\0'

How do I find the current machine's full hostname in C (hostname and domain information)?

The easy way, try uname()

If that does not work, use gethostname() then gethostbyname() and finally gethostbyaddr()

The h_name of hostent{} should be your FQDN

"Automatic" vs "Automatic (Delayed start)"

In short, services set to Automatic will start during the boot process, while services set to start as Delayed will start shortly after boot.

Starting your service Delayed improves the boot performance of your server and has security benefits which are outlined in the article Adriano linked to in the comments.

Update: "shortly after boot" is actually 2 minutes after the last "automatic" service has started, by default. This can be configured by a registry key, according to Windows Internals and other sources (3,4).

The registry keys of interest (At least in some versions of windows) are:

  • HKLM\SYSTEM\CurrentControlSet\services\<service name>\DelayedAutostart will have the value 1 if delayed, 0 if not.
  • HKLM\SYSTEM\CurrentControlSet\services\AutoStartDelay or HKLM\SYSTEM\CurrentControlSet\Control\AutoStartDelay (on Windows 10): decimal number of seconds to wait, may need to create this one. Applies globally to all Delayed services.

Finding height in Binary Search Tree

The problem lies in your base case.

"The height of a tree is the length of the path from the root to the deepest node in the tree. A (rooted) tree with only a node (the root) has a height of zero." - Wikipedia

If there is no node, you want to return -1 not 0. This is because you are adding 1 at the end.

So if there isn't a node, you return -1 which cancels out the +1.

int findHeight(TreeNode<T> aNode) {
    if (aNode == null) {
        return -1;
    }

    int lefth = findHeight(aNode.left);
    int righth = findHeight(aNode.right);

    if (lefth > righth) {
        return lefth + 1;
    } else {
        return righth + 1;
    }
}

Debugging Stored Procedure in SQL Server 2008

MSDN has provided easy way to debug the stored procedure. Please check this link-
How to: Debug Stored Procedures

JPA EntityManager: Why use persist() over merge()?

I found this explanation from the Hibernate docs enlightening, because they contain a use case:

The usage and semantics of merge() seems to be confusing for new users. Firstly, as long as you are not trying to use object state loaded in one entity manager in another new entity manager, you should not need to use merge() at all. Some whole applications will never use this method.

Usually merge() is used in the following scenario:

  • The application loads an object in the first entity manager
  • the object is passed up to the presentation layer
  • some modifications are made to the object
  • the object is passed back down to the business logic layer
  • the application persists these modifications by calling merge() in a second entity manager

Here is the exact semantic of merge():

  • if there is a managed instance with the same identifier currently associated with the persistence context, copy the state of the given object onto the managed instance
  • if there is no managed instance currently associated with the persistence context, try to load it from the database, or create a new managed instance
  • the managed instance is returned
  • the given instance does not become associated with the persistence context, it remains detached and is usually discarded

From: http://docs.jboss.org/hibernate/entitymanager/3.6/reference/en/html/objectstate.html

How do I remove/delete a virtualenv?

step 1: delete virtualenv virtualenvwrapper by copy and paste the following command below:

$ sudo pip uninstall virtualenv virtualenvwrapper

step 2: go to .bashrc and delete all virtualenv and virtualenvwrapper

open terminal:

$ sudo nano .bashrc

scroll down and you will see the code bellow then delete it.

# virtualenv and virtualenvwrapper
export WORKON_HOME=$HOME/.virtualenvs
export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
source /usr/local/bin/virtualenvwrapper.sh

next, source the .bashrc:

$ source ~/.bashrc

FINAL steps: without terminal/shell go to /home and find .virtualenv (I forgot the name so if your find similar to .virtualenv or .venv just delete it. That will work.

Accessing the logged-in user in a template

For symfony 2.6 and above we can use

{{ app.user.getFirstname() }}

as app.security global variable for Twig template has been deprecated and will be removed from 3.0

more info:

http://symfony.com/blog/new-in-symfony-2-6-security-component-improvements

and see the global variables in

http://symfony.com/doc/current/reference/twig_reference.html

What is the difference between the GNU Makefile variable assignments =, ?=, := and +=?

The most upvoted answer can be improved.

Let me refer to GNU Make manual "Setting variables" and "Flavors", and add some comments.

Recursively expanded variables

The value you specify is installed verbatim; if it contains references to other variables, these references are expanded whenever this variable is substituted (in the course of expanding some other string). When this happens, it is called recursive expansion.

foo = $(bar)

The catch: foo will be expanded to the value of $(bar) each time foo is evaluated, possibly resulting in different values. Surely you cannot call it "lazy"! This can surprise you if executed on midnight:

# This variable is haunted!
WHEN = $(shell date -I)

something:
    touch $(WHEN).flag

# If this is executed on 00:00:00:000, $(WHEN) will have a different value!
something-else-later: something
    test -f $(WHEN).flag || echo "Boo!"

Simply expanded variable

VARIABLE := value
VARIABLE ::= value

Variables defined with ‘:=’ or ‘::=’ are simply expanded variables.

Simply expanded variables are defined by lines using ‘:=’ or ‘::=’ [...]. Both forms are equivalent in GNU make; however only the ‘::=’ form is described by the POSIX standard [...] 2012.

The value of a simply expanded variable is scanned once and for all, expanding any references to other variables and functions, when the variable is defined.

Not much to add. It's evaluated immediately, including recursive expansion of, well, recursively expanded variables.

The catch: If VARIABLE refers to ANOTHER_VARIABLE:

VARIABLE := $(ANOTHER_VARIABLE)-yohoho

and ANOTHER_VARIABLE is not defined before this assignment, ANOTHER_VARIABLE will expand to an empty value.

Assign if not set

FOO ?= bar

is equivalent to

ifeq ($(origin FOO), undefined)
FOO = bar
endif

where $(origin FOO) equals to undefined only if the variable was not set at all.

The catch: if FOO was set to an empty string, either in makefiles, shell environment, or command line overrides, it will not be assigned bar.

Appending

VAR += bar

Appending:

When the variable in question has not been defined before, ‘+=’ acts just like normal ‘=’: it defines a recursively-expanded variable. However, when there is a previous definition, exactly what ‘+=’ does depends on what flavor of variable you defined originally.

So, this will print foo bar:

VAR = foo
# ... a mile of code
VAR += $(BAR)
BAR = bar
$(info $(VAR))

but this will print foo:

VAR := foo
# ... a mile of code
VAR += $(BAR)
BAR = bar
$(info $(VAR))

The catch is that += behaves differently depending on what type of variable VAR was assigned before.

Multiline values

The syntax to assign multiline value to a variable is:

define VAR_NAME :=
line
line
endef

or

define VAR_NAME =
line
line
endef

Assignment operator can be omitted, then it creates a recursively-expanded variable.

define VAR_NAME
line
line
endef

The last newline before endef is removed.

Bonus: the shell assignment operator ‘!=’

 HASH != printf '\043'

is the same as

HASH := $(shell printf '\043')

Don't use it. $(shell) call is more readable, and the usage of both in a makefiles is highly discouraged. At least, $(shell) follows Joel's advice and makes wrong code look obviously wrong.

Custom Date/Time formatting in SQL Server

The Datetime format field has the following format 'YYYY-MM-DD HH:MM:SS.S'

That statement is false. That's just how Enterprise Manager or SQL Server chooses to show the date. Internally it's a 8-byte binary value, which is why some of the functions posted by Andrew will work so well.

Kibbee makes a valid point as well, and in a perfect world I would agree with him. However, sometimes you want to bind query results directly to display control or widgets and there's really not a chance to do any formatting. And sometimes the presentation layer lives on a web server that's even busier than the database. With those in mind, it's not necessarily a bad thing to know how to do this in SQL.

Can I load a .NET assembly at runtime and instantiate a type knowing only the name?

Yes. You need to use Assembly.LoadFrom to load the assembly into memory, then you can use Activator.CreateInstance to create an instance of your preferred type. You'll need to look the type up first using reflection. Here is a simple example:

Assembly assembly = Assembly.LoadFrom("MyNice.dll");

Type type = assembly.GetType("MyType");

object instanceOfMyType = Activator.CreateInstance(type);

Update

When you have the assembly file name and the type name, you can use Activator.CreateInstance(assemblyName, typeName) to ask the .NET type resolution to resolve that into a type. You could wrap that with a try/catch so that if it fails, you can perform a search of directories where you may specifically store additional assemblies that otherwise might not be searched. This would use the preceding method at that point.

Java Error: illegal start of expression

Methods can only declare local variables. That is why the compiler reports an error when you try to declare it as public.

In the case of local variables you can not use any kind of accessor (public, protected or private).

You should also know what the static keyword means. In method checkYourself, you use the Integer array locations.

The static keyword distinct the elements that are accessible with object creation. Therefore they are not part of the object itself.

public class Test { //Capitalized name for classes are used in Java
   private final init[] locations; //key final mean that, is must be assigned before object is constructed and can not be changed later. 

   public Test(int[] locations) {
      this.locations = locations;//To access to class member, when method argument has the same name use `this` key word. 
   }

   public boolean checkYourSelf(int value) { //This method is accessed only from a object.
      for(int location : locations) {
         if(location == value) {
            return true; //When you use key word return insied of loop you exit from it. In this case you exit also from whole method.
         }
      }
      return false; //Method should be simple and perform one task. So you can get more flexibility. 
   }
   public static int[] locations = {1,2,3};//This is static array that is not part of object, but can be used in it. 

   public static void main(String[] args) { //This is declaration of public method that is not part of create object. It can be accessed from every place.
      Test test = new Test(Test.locations); //We declare variable test, and create new instance (object) of class Test.  
      String result;
      if(test.checkYourSelf(2)) {//We moved outside the string
        result = "Hurray";        
      } else {
        result = "Try again"
      }
      System.out.println(result); //We have only one place where write is done. Easy to change in future.
   } 
}

JSON - Iterate through JSONArray

Change

JSONObject objects = getArray.getJSONArray(i);

to

JSONObject objects = getArray.getJSONObject(i);

or to

JSONObject objects = getArray.optJSONObject(i);

depending on which JSON-to/from-Java library you're using. (It looks like getJSONObject will work for you.)

Then, to access the string elements in the "objects" JSONObject, get them out by element name.

String a = objects.get("A");

If you need the names of the elements in the JSONObject, you can use the static utility method JSONObject.getNames(JSONObject) to do so.

String[] elementNames = JSONObject.getNames(objects);

"Get the value for the first element and the value for the last element."

If "element" is referring to the component in the array, note that the first component is at index 0, and the last component is at index getArray.length() - 1.


I want to iterate though the objects in the array and get thier component and thier value. In my example the first object has 3 components, the scond has 5 and the third has 4 components. I want iterate though each of them and get thier component name and value.

The following code does exactly that.

import org.json.JSONArray;
import org.json.JSONObject;

public class Foo
{
  public static void main(String[] args) throws Exception
  {
    String jsonInput = "{\"JObjects\":{\"JArray1\":[{\"A\":\"a\",\"B\":\"b\",\"C\":\"c\"},{\"A\":\"a1\",\"B\":\"b2\",\"C\":\"c3\",\"D\":\"d4\",\"E\":\"e5\"},{\"A\":\"aa\",\"B\":\"bb\",\"C\":\"cc\",\"D\":\"dd\"}]}}";

    // "I want to iterate though the objects in the array..."
    JSONObject outerObject = new JSONObject(jsonInput);
    JSONObject innerObject = outerObject.getJSONObject("JObjects");
    JSONArray jsonArray = innerObject.getJSONArray("JArray1");
    for (int i = 0, size = jsonArray.length(); i < size; i++)
    {
      JSONObject objectInArray = jsonArray.getJSONObject(i);

      // "...and get thier component and thier value."
      String[] elementNames = JSONObject.getNames(objectInArray);
      System.out.printf("%d ELEMENTS IN CURRENT OBJECT:\n", elementNames.length);
      for (String elementName : elementNames)
      {
        String value = objectInArray.getString(elementName);
        System.out.printf("name=%s, value=%s\n", elementName, value);
      }
      System.out.println();
    }
  }
}
/*
OUTPUT:
3 ELEMENTS IN CURRENT OBJECT:
name=A, value=a
name=B, value=b
name=C, value=c

5 ELEMENTS IN CURRENT OBJECT:
name=D, value=d4
name=E, value=e5
name=A, value=a1
name=B, value=b2
name=C, value=c3

4 ELEMENTS IN CURRENT OBJECT:
name=D, value=dd
name=A, value=aa
name=B, value=bb
name=C, value=cc
*/

Set View Width Programmatically

in code add below line:

spin27.setLayoutParams(new LinearLayout.LayoutParams(200, 120));

What is the "double tilde" (~~) operator in JavaScript?

~(5.5)   // => -6
~(-6)    // => 5
~~5.5    // => 5  (same as Math.floor(5.5))
~~(-5.5) // => -5 (NOT the same as Math.floor(-5.5), which would give -6 )

For more info, see:

How to determine the last Row used in VBA including blank spaces in between

The best way to get number of last row used is:

ActiveSheet.UsedRange.Rows.Count for the current sheet.

Worksheets("Sheet name").UsedRange.Rows.Count for a specific sheet.

To get number of the last column used:

ActiveSheet.UsedRange.Columns.Count for the current sheet.

Worksheets("Sheet name").UsedRange.Columns.Count for a specific sheet.

I hope this helps.

Abdo

"Fade" borders in CSS

You could also use box-shadow property with higher value of blur and rgba() color to set opacity level. Sounds like a better choice in your case.

box-shadow: 0 30px 40px rgba(0,0,0,.1);

Compiling and Running Java Code in Sublime Text 2

I find the method in the post Compile and Run Java programs with Sublime Text 2 works well and is a little more convenient than the other methods. Here is a link to the archived page.

For Windows:

Step 1:

Create runJava.bat with the following code.

@ECHO OFF
cd %~dp1
ECHO Compiling %~nx1.......
IF EXIST %~n1.class (
DEL %~n1.class
)
javac %~nx1
IF EXIST %~n1.class (
ECHO -----------OUTPUT-----------
java %~n1
)

Copy this file to jdk bin directory.

Step 2:

  1. Open Sublime package directory using Preferences > Browse Packages..
  2. Go to Java Folder
  3. Open JavaC.sublime-build and replace line
    "cmd": ["javac", "$file"],
    with
    "cmd": ["runJava.bat", "$file"],

Done!

Write programs and Run using CTRL + B

Note: Instructions are different for Sublime 3.

How do I get AWS_ACCESS_KEY_ID for Amazon?

It is very dangerous to create an access_key_id in "My Account ==> Security Credentials". Because the key has all authority. Please create "IAM" user and attach only some policies you need.

Better/Faster to Loop through set or list?

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

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

How to access the contents of a vector from a pointer to the vector in C++?

vector<int> v;
v.push_back(906);
vector<int> * p = &v;
cout << (*p)[0] << endl;

How can I append a query parameter to an existing URL?

An update to Adam's answer considering tryp's answer too. Don't have to instantiate a String in the loop.

public static URI appendUri(String uri, Map<String, String> parameters) throws URISyntaxException {
    URI oldUri = new URI(uri);
    StringBuilder queries = new StringBuilder();

    for(Map.Entry<String, String> query: parameters.entrySet()) {
        queries.append( "&" + query.getKey()+"="+query.getValue());
    }

    String newQuery = oldUri.getQuery();
    if (newQuery == null) {
        newQuery = queries.substring(1);
    } else {
        newQuery += queries.toString();
    }

    URI newUri = new URI(oldUri.getScheme(), oldUri.getAuthority(),
            oldUri.getPath(), newQuery, oldUri.getFragment());

    return newUri;
}

Count lines in large files

Your limiting speed factor is the I/O speed of your storage device, so changing between simple newlines/pattern counting programs won't help, because the execution speed difference between those programs are likely to be suppressed by the way slower disk/storage/whatever you have.

But if you have the same file copied across disks/devices, or the file is distributed among those disks, you can certainly perform the operation in parallel. I don't know specifically about this Hadoop, but assuming you can read a 10gb the file from 4 different locations, you can run 4 different line counting processes, each one in one part of the file, and sum their results up:

$ dd bs=4k count=655360 if=/path/to/copy/on/disk/1/file | wc -l &
$ dd bs=4k skip=655360 count=655360 if=/path/to/copy/on/disk/2/file | wc -l &
$ dd bs=4k skip=1310720 count=655360 if=/path/to/copy/on/disk/3/file | wc -l &
$ dd bs=4k skip=1966080 if=/path/to/copy/on/disk/4/file | wc -l &

Notice the & at each command line, so all will run in parallel; dd works like cat here, but allow us to specify how many bytes to read (count * bs bytes) and how many to skip at the beginning of the input (skip * bs bytes). It works in blocks, hence, the need to specify bs as the block size. In this example, I've partitioned the 10Gb file in 4 equal chunks of 4Kb * 655360 = 2684354560 bytes = 2.5GB, one given to each job, you may want to setup a script to do it for you based on the size of the file and the number of parallel jobs you will run. You need also to sum the result of the executions, what I haven't done for my lack of shell script ability.

If your filesystem is smart enough to split big file among many devices, like a RAID or a distributed filesystem or something, and automatically parallelize I/O requests that can be paralellized, you can do such a split, running many parallel jobs, but using the same file path, and you still may have some speed gain.

EDIT: Another idea that occurred to me is, if the lines inside the file have the same size, you can get the exact number of lines by dividing the size of the file by the size of the line, both in bytes. You can do it almost instantaneously in a single job. If you have the mean size and don't care exactly for the the line count, but want an estimation, you can do this same operation and get a satisfactory result much faster than the exact operation.

UEFA/FIFA scores API

UEFA or FIFA don't seem to provide any API to get the information you want. However, there are some third-party services which support that:

  • OPTA - Both commercial and free. They have incredible database about matches. Whoscored.com currently uses it.

  • Others: livescoreboards, xmlsoccer, ...

How much data can a List can hold at the maximum?

The interface however defines the size() method, which returns an int.

Returns the number of elements in this list. If this list contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

So, no limit, but after you reach Integer.MAX_VALUE, the behaviour of the list changes a bit

ArrayList (which is tagged) is backed by an array, and is limited to the size of the array - i.e. Integer.MAX_VALUE

How to multiply duration by integer?

For multiplication of variable to time.Second using following code

    oneHr:=3600
    addOneHrDuration :=time.Duration(oneHr)
    addOneHrCurrTime := time.Now().Add(addOneHrDuration*time.Second)

Why am I getting this redefinition of class error?

the implementation in the cpp file should be in the form

gameObject::gameObject()
    {
    x = 0;
    y = 0;
    }
gameObject::gameObject(int inx, int iny)
    {
        x = inx;
        y = iny;
    }

gameObject::~gameObject()
    {
    //
    }
int gameObject::add()
    {
        return x+y;
    }

not within a class gameObject { } definition block

How to set ANDROID_HOME path in ubuntu?

In the terminal just type these 3 commands to set the ANDROID_HOME Variable :

$ export ANDROID_HOME=~/Android/Sdk 

/Android/Sdk is the location of Sdk, this might get change in your case

$ PATH=$PATH:$ANDROID_HOME/tools
$ PATH=$PATH:$ANDROID_HOME/platform-tools `   

Note : This will set the path temporarily so what ever action you have to perform, perform on the same terminal.

How to use sudo inside a docker container?

If SUDO or apt-get is not accessible inside the Container, You can use, below option in running container.

docker exec -u root -it f83b5c5bf413 ash

"f83b5c5bf413" is my container ID & here is working example from my terminal:

enter image description here

How does the JPA @SequenceGenerator annotation work

Now, back to your questions:

Q1. Does this sequence generator make use of the database's increasing numeric value generating capability or generates the number on its own?

By using the GenerationType.SEQUENCE strategy on the @GeneratedValue annotation, the JPA provider will try to use a database sequence object of the underlying database that supports this feature (e.g., Oracle, SQL Server, PostgreSQL, MariaDB).

If you are using MySQL, which doesn't support database sequence objects, then Hibernate is going to fall back to using the GenerationType.TABLE instead, which is undesirable since the TABLE generation performs badly.

So, don't use the GenerationType.SEQUENCE strategy with MySQL.

Q2. If JPA uses a database auto-increment feature, then will it work with datastores that don't have auto-increment feature?

I assume you are talking about the GenerationType.IDENTITY when you say database auto-increment feature.

To use an AUTO_INCREMENT or IDENTITY column, you need to use the GenerationType.IDENTITYstrategy on the @GeneratedValue annotation.

Q3. If JPA generates numeric value on its own, then how does the JPA implementation know which value to generate next? Does it consult with the database first to see what value was stored last in order to generate the value (last + 1)?

The only time when the JPA provider generates values on its own is when you are using the sequence-based optimizers, like:

These optimizers are meat to reduce the number of database sequence calls, so they multiply the number of identifier values that can be generated using a single database sequence call.

To avoid conflicts between Hibernate identifier optimizers and other 3rd-party clients, you should use pooled or pooled-lo instead of hi/lo. Even if you are using a legacy application that was designed to use hi/lo, you can migrate to the pooled or pooled-lo optimizers.

Q4. Please also shed some light on sequenceName and allocationSize properties of @SequenceGenerator annotation.

The sequenceName attribute defines the database sequence object to be used to generate the identifier values. IT's the object you created using the CREATE SEQUENCE DDL statement.

So, if you provide this mapping:

@Id
@GeneratedValue(
    strategy = GenerationType.SEQUENCE,
    generator = "seq_post"
)
@SequenceGenerator(
    name = "seq_post"
)
private Long id;

Hibernate is going to use the seq_post database object to generate the identifier values:

SELECT nextval('hibernate_sequence')

The allocationSize defines the identifier value multiplier, and if you provide a value that's greater than 1, then Hibernate is going to use the pooled optimizer, to reduce the number of database sequence calls.

So, if you provide this mapping:

@Id
@GeneratedValue(
    strategy = GenerationType.SEQUENCE,
    generator = "seq_post"
)
@SequenceGenerator(
    name = "seq_post",
    allocationSize = 5
)
private Long id;

Then, when you persist 5 entities:

for (int i = 1; i <= 5; i++) {
    entityManager.persist(
        new Post().setTitle(
            String.format(
                "High-Performance Java Persistence, Part %d",
                i
            )
        )
    );
}

Only 2 database sequence calls will be executed, instead of 5:

SELECT nextval('hibernate_sequence')
SELECT nextval('hibernate_sequence')
 
INSERT INTO post (title, id)
VALUES ('High-Performance Java Persistence, Part 1', 1)
 
INSERT INTO post (title, id)
VALUES ('High-Performance Java Persistence, Part 2', 2)
 
INSERT INTO post (title, id)
VALUES ('High-Performance Java Persistence, Part 3', 3)
 
INSERT INTO post (title, id)
VALUES ('High-Performance Java Persistence, Part 4', 4)
 
INSERT INTO post (title, id)
VALUES ('High-Performance Java Persistence, Part 5', 5)

How to loop and render elements in React-native?

render() {
  return (
    <View style={...}>
       {initialArr.map((prop, key) => {
         return (
           <Button style={{borderColor: prop[0]}}  key={key}>{prop[1]}</Button>
         );
      })}
     </View>
  )
}

should do the trick

Check if a div does NOT exist with javascript

There's an even better solution. You don't even need to check if the element returns null. You can simply do this:

if (document.getElementById('elementId')) {
  console.log('exists')
}

That code will only log exists to console if the element actually exists in the DOM.

How to declare and display a variable in Oracle

Make sure that, server output is on otherwise output will not be display;

sql> set serveroutput on;

declare
  n number(10):=1;
begin
  while n<=10
 loop
   dbms_output.put_line(n);
   n:=n+1;
 end loop;
end;
/

Outout: 1 2 3 4 5 6 7 8 9 10

Live video streaming using Java?

Hi not an expert in streaming but my understanding is that it is included in th Java Media Framework JMF http://java.sun.com/javase/technologies/desktop/media/jmf/2.1.1/support-rtsp.html

How to run a C# console application with the console hidden

If you are using Process Class then you can write

yourprocess.StartInfo.UseShellExecute = false;
yourprocess.StartInfo.CreateNoWindow = true;

before yourprocess.start(); and process will be hidden

Fixing Segmentation faults in C++

  1. Compile your application with -g, then you'll have debug symbols in the binary file.

  2. Use gdb to open the gdb console.

  3. Use file and pass it your application's binary file in the console.

  4. Use run and pass in any arguments your application needs to start.

  5. Do something to cause a Segmentation Fault.

  6. Type bt in the gdb console to get a stack trace of the Segmentation Fault.

How to make inline plots in Jupyter Notebook larger?

To adjust the size of one figure:

import matplotlib.pyplot as plt

fig=plt.figure(figsize=(15, 15))

To change the default settings, and therefore all your plots:

import matplotlib.pyplot as plt

plt.rcParams['figure.figsize'] = [15, 15]

How do I configure IIS for URL Rewriting an AngularJS application in HTML5 mode?

In my case I kept getting a 403.14 after I had setup the correct rewrite rules. It turns out that I had a directory that was the same name as one of my URL routes. Once I removed the IsDirectory rewrite rule my routes worked correctly. Is there a case where removing the directory negation may cause problems? I can't think of any in my case. The only case I can think of is if you can browse a directory with your app.

<rule name="fixhtml5mode" stopProcessing="true">
  <match url=".*"/>
  <conditions logicalGrouping="MatchAll">
    <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
  </conditions>
  <action type="Rewrite" url="/" />
</rule>

JBoss vs Tomcat again

Take a look at TOMEE

It has all the features that you need to build a complete Java EE app.

Resolve build errors due to circular dependency amongst classes

I've written a post about this once: Resolving circular dependencies in c++

The basic technique is to decouple the classes using interfaces. So in your case:

//Printer.h
class Printer {
public:
    virtual Print() = 0;
}

//A.h
#include "Printer.h"
class A: public Printer
{
    int _val;
    Printer *_b;
public:

    A(int val)
        :_val(val)
    {
    }

    void SetB(Printer *b)
    {
        _b = b;
        _b->Print();
    }

    void Print()
    {
        cout<<"Type:A val="<<_val<<endl;
    }
};

//B.h
#include "Printer.h"
class B: public Printer
{
    double _val;
    Printer* _a;
public:

    B(double val)
        :_val(val)
    {
    }

    void SetA(Printer *a)
    {
        _a = a;
        _a->Print();
    }

    void Print()
    {
        cout<<"Type:B val="<<_val<<endl;
    }
};

//main.cpp
#include <iostream>
#include "A.h"
#include "B.h"

int main(int argc, char* argv[])
{
    A a(10);
    B b(3.14);
    a.Print();
    a.SetB(&b);
    b.Print();
    b.SetA(&a);
    return 0;
}

How to hide command output in Bash

.SILENT:

Type " .SILENT: " in the beginning of your script without colons.

xampp MySQL does not start

If there are two instances of MySql it's normal that it gives such an error if they both run at the same time. If you really need 2 servers, you must change the listening port of one of them, or if you don't it's probably better to simply uninstall one of them. This is so regarless of MySql itself, because two programs cannot listen on the same port at the same time.

PHP convert XML to JSON

After researching a little bit all of the answers, I came up with a solution that worked just fine with my JavaScript functions across browsers (Including consoles / Dev Tools) :

<?php

 // PHP Version 7.2.1 (Windows 10 x86)

 function json2xml( $domNode ) {
  foreach( $domNode -> childNodes as $node) {
   if ( $node -> hasChildNodes() ) { json2xml( $node ); }
   else {
    if ( $domNode -> hasAttributes() && strlen( $domNode -> nodeValue ) ) {
     $domNode -> setAttribute( "nodeValue", $node -> textContent );
     $node -> nodeValue = "";
    }
   }
  }
 }

 function jsonOut( $file ) {
  $dom = new DOMDocument();
  $dom -> loadXML( file_get_contents( $file ) );
  json2xml( $dom );
  header( 'Content-Type: application/json' );
  return str_replace( "@", "", json_encode( simplexml_load_string( $dom -> saveXML() ), JSON_PRETTY_PRINT ) );
 }

 $output = jsonOut( 'https://boxelizer.com/assets/a1e10642e9294f39/b6f30987f0b66103.xml' );

 echo( $output );

 /*
  Or simply 
  echo( jsonOut( 'https://boxelizer.com/assets/a1e10642e9294f39/b6f30987f0b66103.xml' ) );
 */

?>

It basically creates a new DOMDocument, loads and XML file into it and traverses through each one of the nodes and children getting the data / parameters and exporting it into JSON without the annoying "@" signs.

Link to the XML file.

UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 13: ordinal not in range(128)

For me there was a problem with the terminal encoding. Adding UTF-8 to .bashrc solved the problem:

export LC_CTYPE=en_US.UTF-8

Don't forget to reload .bashrc afterwards:

source ~/.bashrc

Dart SDK is not configured

similar to above, I got the dart sdk path from a project I created with flutter(not cloned) by going to Android Studio Preferences | Languages & Frameworks | Dart. Then similarly in the cloned project go to Preferences | Languages & Frameworks | Dart and "Enable Dart support for the project..." and enter the path you saved.

Changing default startup directory for command prompt in Windows 7

Edit: It actually seems that editing the file shortcut breaks the Win+x, c key shortcut. (Moral of the story: only change system files you know how to fix! Eventually after a Windows update it repaired itself.)

What I ended up doing is creating a new customized Command Prompt shortcut in the start folder and pinned to the taskbar that I launch instead of cmd.exe


As other answers point out, changing the registry Autorun cmd start location is a bad idea because it silently will break other programs that shell out for tasks, like Visual Studio Code.

You should just change whatever shortcut you use to open cmd to have a Start In entry.

If you use Win+x, c to launch cmd, you can edit the Start In for

"%LOCALAPPDATA%\Microsoft\Windows\WinX\Group3\02 - Command Prompt.lnk"

Change form size at runtime in C#

You cannot change the Width and Height properties of the Form as they are readonly. You can change the form's size like this:

button1_Click(object sender, EventArgs e)
{
    // This will change the Form's Width and Height, respectively.
    this.Size = new Size(420, 200);
}

Add shadow to custom shape on Android

I think this method produces very good results:

<!-- Drop Shadow Stack -->
<item>
    <shape>
        <padding
                android:top="1dp"
                android:right="1dp"
                android:bottom="1dp"
                android:left="1dp"/>
        <solid android:color="#00CCCCCC"/>
    </shape>
</item>
<item>
    <shape>
        <padding
                android:top="1dp"
                android:right="1dp"
                android:bottom="1dp"
                android:left="1dp"/>
        <solid android:color="#10CCCCCC"/>
    </shape>
</item>
<item>
    <shape>
        <padding
                android:top="1dp"
                android:right="1dp"
                android:bottom="1dp"
                android:left="1dp"/>
        <solid android:color="#20CCCCCC"/>
    </shape>
</item>
<item>
    <shape>
        <padding
                android:top="1dp"
                android:right="1dp"
                android:bottom="1dp"
                android:left="1dp"/>
        <solid android:color="#30CCCCCC"/>
    </shape>
</item>
<item>
    <shape>
        <padding
                android:top="1dp"
                android:right="1dp"
                android:bottom="1dp"
                android:left="1dp"/>
        <solid android:color="#50CCCCCC"/>
    </shape>
</item>

<item>

    <shape android:shape="rectangle">
        <stroke android:color="#CCC" android:width="1dp"/>
        <solid android:color="#FFF" />
        <corners android:radius="2dp" />

    </shape>

</item>

How to check if a double is null?

To say that something "is null" means that it is a reference to the null value. Primitives (int, double, float, etc) are by definition not reference types, so they cannot have null values. You will need to find out what your database wrapper will do in this case.

Session state can only be used when enableSessionState is set to true either in a configuration

I have got this error only when debugging the ASP .Net Application.

I also had Session["mysession"] kind of variables added into my Watch of Visual Studio.

the issue was solved Once, I have removed the Session Variables from watch.

The Network Adapter could not establish the connection when connecting with Oracle DB

If it is on a Linux box, I would suggest you add the database IP name and IP resolution to the /etc/hosts.

I have the same error and when we do the above, it works fine.

What are the main performance differences between varchar and nvarchar SQL Server data types?

Why, in all this discussion, has there been no mention of UTF-8? Being able to store the full unicode span of characters does not mean one has to always allocate two-bytes-per-character (or "code point" to use the UNICODE term). All of ASCII is UTF-8. Does SQL Server check for VARCHAR() fields that the text is strict ASCII (i.e. top byte bit zero)? I would hope not.

If then you want to store unicode and want compatibility with older ASCII-only applications, I would think using VARCHAR() and UTF-8 would be the magic bullet: It only uses more space when it needs to.

For those of you unfamiliar with UTF-8, might I recommend a primer.

Could not find method compile() for arguments Gradle

Hope Below steps will help

Add the dependency to your project-level build.gradle:

classpath 'com.google.gms:google-services:3.0.0'

Add the plugin to your app-level build.gradle:

apply plugin: 'com.google.gms.google-services'

app-level build.gradle:

dependencies {
        compile 'com.google.android.gms:play-services-auth:9.8.0'
}

Python: Checking if a 'Dictionary' is empty doesn't seem to work

test_dict = {}
if not test_dict.keys():
    print "Dict is Empty"

How do I set up IntelliJ IDEA for Android applications?

I had some issues that this didn't address in getting this environment set up on OSX. It had to do with the solution that I was maintaining having additional dependencies on some of the Google APIs. It wasn't enough to just download and install the items listed in the first response.

You have to download these.

  1. Run Terminal
  2. Navigate to the android/sdk directory
  3. Type "android" You will get a gui. Check the "Tools" directory and the latest Android API (at this time, it's 4.3 (API 18)).
  4. Click "Install xx packages" and go watch an episode of Breaking Bad or something. It'll take a while.
  5. Go back to IntelliJ and open the "Project Structure..." dialog (Cmd+;).
  6. In the left panel of the dialog, under "Project Settings," select Project. In the right panel, under "Project SDK," click "New..." > Android SDK and navigate to your android/sdk directory. Choose this and you will be presented with a dialog with which you can add the "Google APIs" build target. This is what I needed. You may need to do this more than once if you have multiple version targets.
  7. Now, under the left pane "Modules," with your project selected in the center pane, select the appropriate module under the "Dependencies" tab in the right pane.

Disable HTTP OPTIONS, TRACE, HEAD, COPY and UNLOCK methods in IIS

For anyone looking for a UI option using IIS Manager.

  1. Open the Website in IIS Manager
  2. Go To Request Filtering and open the Request Filtering Window.
  3. Go to Verbs Tab and Add HTTP Verbs to "Allow Verb..." or "Deny Verb...". This allow to add the HTTP Verbs in the "Deny Verb.." Collection.

Request Filtering Window in IIS Manager Request Filtering Window in IIS Manager

Add Verb... or Deny Verb... enter image description here

initialize a numpy array

Array analogue for the python's

a = []
for i in range(5):
    a.append(i)

is:

import numpy as np

a = np.empty((0))
for i in range(5):
    a = np.append(a, i)

How to convert JSON object to an Typescript array?

To convert any JSON to array, use the below code:

const usersJson: any[] = Array.of(res.json());

SQL Count for each date

Your created_date field is datetime, so you'll need to strip off the time before the grouping will work if you want to go by date:

SELECT COUNT(created_date), created_date 
FROM table 
WHERE DATEDIFF(created_date, getdate()) < 10
GROUP BY convert(varchar, created_date, 101)

Best way to resolve file path too long exception

The best answer I can find, is in one of the comments here. Adding it to the answer so that someone won't miss the comment and should definitely try this out. It fixed the issue for me.

We need to map the solution folder to a drive using the "subst" command in command prompt- e.g., subst z:

And then open the solution from this drive (z in this case). This would shorten the path as much as possible and could solve the lengthy filename issue.

jQuery add blank option to top of list and make selected to existing dropdown

Solution native Javascript :

document.getElementById("theSelectId").insertBefore(new Option('', ''), document.getElementById("theSelectId").firstChild);

example : http://codepen.io/anon/pen/GprybL

Styling mat-select in Angular Material

Put your class name on the mat-form-field element. This works for all inputs.

Get TimeZone offset value from TimeZone without TimeZone name

With Java 8, you can achieve this by following code.

    TimeZone tz = TimeZone.getDefault();
    String offsetId = tz.toZoneId().getRules().getStandardOffset(Instant.now()).getId();

and the offsetId will be something like +01:00

Please notice the function getStandardOffset need a Instant as parameter. It is the specific time point, at which you want to check the offset of given timezone, as timezone's offset may varies during time. For the reason of some areas have Daylight Saving Time.

I think it is the reason why @Tomasz Nurkiewicz recommand not to store offset in signed hour format directly, but to check the offset each time you need it.

How to hide .php extension in .htaccess

I've used this:

RewriteEngine On

# Unless directory, remove trailing slash
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^([^/]+)/$ http://example.com/folder/$1 [R=301,L]

# Redirect external .php requests to extensionless URL
RewriteCond %{THE_REQUEST} ^(.+)\.php([#?][^\ ]*)?\ HTTP/
RewriteRule ^(.+)\.php$ http://example.com/folder/$1 [R=301,L]

# Resolve .php file for extensionless PHP URLs
RewriteRule ^([^/.]+)$ $1.php [L]

See also: this question

URL to load resources from the classpath in Java

I think this is worth its own answer - if you're using Spring, you already have this with

Resource firstResource =
    context.getResource("http://www.google.fi/");
Resource anotherResource =
    context.getResource("classpath:some/resource/path/myTemplate.txt");

Like explained in the spring documentation and pointed out in the comments by skaffman.

Sending simple message body + file attachment using Linux Mailx

You can try this:

(cat ./body.txt)|mailx -s "subject text" -a "attchement file" [email protected]

Python 3 turn range to a list

in Python 3.x, the range() function got its own type. so in this case you must use iterator

list(range(1000))

CSS container div not getting height

Try inserting this clearing div before the last </div>

<div style="clear: both; line-height: 0;">&nbsp;</div>

Detect when input has a 'readonly' attribute

Check the current value of your "readonly" attribute, if it's "false" (a string) or empty (undefined or "") then it's not readonly.

$('input').each(function() {
    var readonly = $(this).attr("readonly");
    if(readonly && readonly.toLowerCase()!=='false') { // this is readonly
        alert('this is a read only field');
    }
});

How do I get the value of text input field using JavaScript?

You can read value by

searchTxt.value

_x000D_
_x000D_
function searchURL() {
   let txt = searchTxt.value;
   console.log(txt);
   // window.location = "http://www.myurl.com/search/" + txt; ...
}

document.querySelector('.search').addEventListener("click", ()=>searchURL());
_x000D_
<input name="searchTxt" type="text" maxlength="512" id="searchTxt" class="searchField"/>

<button class="search">Search</button>
_x000D_
_x000D_
_x000D_

UPDATE

I see many downvotes but any comments - however (for future readers) actually this solution works

how to add picasso library in android studio

Add the Picasso library in Dependency

dependencies {
       ...
       implementation 'com.squareup.picasso:picasso:2.71828'
       ...
    }

Sync The Project Create one imageview in Layout

<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/imageView"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true">
</ImageView>

Add the Internet permission in Manifest file

<uses-permission android:name="android.permission.INTERNET" />

//Initialize ImageView

ImageView imageView = (ImageView) findViewById(R.id.imageView);

//Loading image from below url into imageView

Picasso.get()
   .load("YOUR IMAGE URL HERE")
   .into(imageView);

Undefined reference to `sin`

I have the problem anyway with -lm added

gcc -Wall -lm mtest.c -o mtest.o
mtest.c: In function 'f1':
mtest.c:6:12: warning: unused variable 'res' [-Wunused-variable]
/tmp/cc925Nmf.o: In function `f1':
mtest.c:(.text+0x19): undefined reference to `sin'
collect2: ld returned 1 exit status

I discovered recently that it does not work if you first specify -lm. The order matters:

gcc mtest.c -o mtest.o -lm

Just link without problems

So you must specify the libraries after.

Array initialization in Perl

What do you mean by "initialize an array to zero"? Arrays don't contain "zero" -- they can contain "zero elements", which is the same as "an empty list". Or, you could have an array with one element, where that element is a zero: my @array = (0);

my @array = (); should work just fine -- it allocates a new array called @array, and then assigns it the empty list, (). Note that this is identical to simply saying my @array;, since the initial value of a new array is the empty list anyway.

Are you sure you are getting an error from this line, and not somewhere else in your code? Ensure you have use strict; use warnings; in your module or script, and check the line number of the error you get. (Posting some contextual code here might help, too.)

std::vector versus std::array in C++

A vector is a container class while an array is an allocated memory.

Fill Combobox from database

To use the Combobox in the way you intend, you could pass in an object to the cmbTripName.Items.Add method.

That object should have FleetID and FleetName properties:

while (drd.Read())
{
    cmbTripName.Items.Add(new Fleet(drd["FleetID"].ToString(), drd["FleetName"].ToString()));
}
cmbTripName.ValueMember = "FleetId";
cmbTripName.DisplayMember = "FleetName";

The Fleet Class:

class Fleet
{
     public Fleet(string fleetId, string fleetName)
     {
           FleetId = fleetId;
           FleetName = fleetName
     }
     public string FleetId {get;set;}
     public string FleetName {get;set;}
}

Or, You could probably do away with the need for a Fleet class completely by using an anonymous type...

while (drd.Read())
{
    cmbTripName.Items.Add(new {FleetId = drd["FleetID"].ToString(), FleetName = drd["FleetName"].ToString()});
}
cmbTripName.ValueMember = "FleetId";
cmbTripName.DisplayMember = "FleetName";

HTML Code for text checkbox '?'

Just make sure that your HTML file is encoded with UTF-8 and that your web server sends a HTTP header with that charset, then you just can write that character directly into your HTMl file.

http://www.w3.org/International/O-HTTP-charset

If you can't use UTF-8 for some reason, you can look up the codes in a unicode list such as http://en.wikipedia.org/wiki/List_of_Unicode_characters and use &#xABCD; where ABCD is the hexcode from that list (U+ABCD).

SQL datetime format to date only

After perusing your previous questions I eventually determined you are probably on SQL Server 2005. For US format you would use style 101

select Subject, 
       CONVERT(varchar,DeliveryDate,101) as DeliveryDate
from Email_Administration 
where MerchantId =@MerchantID 

Git - Ignore node_modules folder everywhere

Use the universal one-liner in terminal in the project directory:

touch .gitignore && echo "node_modules/" >> .gitignore && git rm -r --cached node_modules ; git status

It works no matter if you've created a .gitignore or not, no matter if you've added node_modules to git tracking or not.

Then commit and push the .gitignore changes.

Explanation

touch will generate the .gitignore file if it doesn't already exist.

echo and >> will append node_modules/ at the end of .gitignore, causing the node_modules folder and all subfolders to be ignored.

git rm -r --cached removes the node_modules folder from git control if it was added before. Otherwise, this will show a warning pathspec 'node_modules' did not match any files, which has no side effects and you can safely ignore. The flags cause the removal to be recursive and include the cache.

git status displays the new changes. A change to .gitignore will appear, while node_modules will not appear as it is no longer being tracked by git.

Checkbox angular material checked by default

If you are using Reactive form you can set it to default like this:

In the form model, set the value to false. So if it's checked its value will be true else false

let form = this.formBuilder.group({
    is_known: [false]
})

//In HTML

 <mat-checkbox matInput formControlName="is_known">Known</mat-checkbox>

print arraylist element?

Here is an updated solution for Java8, using lambdas and streams:

System.out.println(list.stream()
                       .map(Object::toString)
                       .collect(Collectors.joining("\n")));

Or, without joining the list into one large string:

list.stream().forEach(System.out::println);

Should I initialize variable within constructor or outside constructor

Both the options can be correct depending on your situation.

A very simple example would be: If you have multiple constructors all of which initialize the variable the same way(int x=2 for each one of them). It makes sense to initialize the variable at declaration to avoid redundancy.

It also makes sense to consider final variables in such a situation. If you know what value a final variable will have at declaration, it makes sense to initialize it outside the constructors. However, if you want the users of your class to initialize the final variable through a constructor, delay the initialization until the constructor.

Downloading a Google font and setting up an offline site that uses it

You need to download the font and reference it locally.

Download the CSS from the link you posted, then download all of the WOFF files and (if needed) convert them to TTF.

Then change the CSS from the link you posted to include the fonts locally.

From

url(http://themes.googleusercontent.com/static/fonts/opensans/v6/
DXI1ORHCpsQm3Vp6mXoaTXhCUOGz7vYGh680lGh-uXM.woff)

To

url(/path/to/font/font.woff)

Voila! There might be some more you need to do but the above is the basics. This article explains a little better.

Why do I have to run "composer dump-autoload" command to make migrations work in laravel?

OK so I think i know the issue you're having.

Basically, because Composer can't see the migration files you are creating, you are having to run the dump-autoload command which won't download anything new, but looks for all of the classes it needs to include again. It just regenerates the list of all classes that need to be included in the project (autoload_classmap.php), and this is why your migration is working after you run that command.

How to fix it (possibly) You need to add some extra information to your composer.json file.

"autoload": {
    "classmap": [
        "PATH TO YOUR MIGRATIONS FOLDER"
    ],
}

You need to add the path to your migrations folder to the classmap array. Then run the following three commands...

php artisan clear-compiled 
composer dump-autoload
php artisan optimize

This will clear the current compiled files, update the classes it needs and then write them back out so you don't have to do it again.

Ideally, you execute composer dump-autoload -o , for a faster load of your webpages. The only reason it is not default, is because it takes a bit longer to generate (but is only slightly noticable).

Hope you can manage to get this sorted, as its very annoying indeed :(

Java error: Implicit super constructor is undefined for default constructor

For those who Google for this error and arrive here: there might be another reason for receiving it. Eclipse gives this error when you have project setup - system configuration mismatch.

For example, if you import Java 1.7 project to Eclipse and you do not have 1.7 correctly set up then you will get this error. Then you can either go to Project - Preference - Java - Compiler and switch to 1.6 or earlier; or go to Window - Preferences - Java - Installed JREs and add/fix your JRE 1.7 installation.

Concatenating date with a string in Excel

You can do it this simple way :

A1 = Mahi
A2 = NULL(blank)

Select A2 Right click on cell --> Format cells --> change to TEXT

Then put the date in A2 (A2 =31/07/1990)

Then concatenate it will work. No need of any formulae.

=CONCATENATE(A1,A2)

mahi31/07/1990

(This works on the empty cells ie.,Before entering the DATE value to cell you need to make it as TEXT).

phonegap open link in browser

If you happen to have jQuery around, you can intercept the click on the link like this:

$(document).on('click', 'a', function (event) {
    event.preventDefault();
    window.open($(this).attr('href'), '_system');
    return false;
});

This way you don't have to modify the links in the html, which can save a lot of time. I have set this up using a delegate, that's why you see it being tied to the document object, with the 'a' tag as the second argument. This way all 'a' tags will be handled, regardless of when they are added.

Ofcourse you still have to install the InAppBrowser plug-in:

cordova plugin add org.apache.cordova.inappbrowser

Failed to serialize the response in Web API with Json

This is my error

I basically add one line which they are

  • entities.Configuration.ProxyCreationEnabled = false;

to UsersController.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.Http;
using UserDataAccess;

namespace SBPMS.Controllers
{
    public class UsersController : ApiController
    {


        public IEnumerable<User> Get() {
            using (SBPMSystemEntities entities = new SBPMSystemEntities()) {
                entities.Configuration.ProxyCreationEnabled = false;
                return entities.Users.ToList();
            }
        }
        public User Get(int id) {
            using (SBPMSystemEntities entities = new SBPMSystemEntities()) {
                entities.Configuration.ProxyCreationEnabled = false;
                return entities.Users.FirstOrDefault(e => e.user_ID == id);
            }
        }
    }
}

Here is my output:

How to execute the start script with Nodemon

If you have nodemon installed globally, simply running nodemon in your project will automatically run the start script from package.json.

For example:

"scripts": {
  "start": "node src/server.js"
},

From the nodemon documentation:

nodemon will also search for the scripts.start property in package.json (as of nodemon 1.1.x).

How do I enumerate through a JObject?

For people like me, linq addicts, and based on svick's answer, here a linq approach:

using System.Linq;
//...
//make it linq iterable. 
var obj_linq = Response.Cast<KeyValuePair<string, JToken>>();

Now you can make linq expressions like:

JToken x = obj_linq
          .Where( d => d.Key == "my_key")
          .Select(v => v)
          .FirstOrDefault()
          .Value;
string y = ((JValue)x).Value;

Or just:

var y = obj_linq
       .Where(d => d.Key == "my_key")
       .Select(v => ((JValue)v.Value).Value)
       .FirstOrDefault();

Or this one to iterate over all data:

obj_linq.ToList().ForEach( x => { do stuff } ); 

How to put individual tags for a scatter plot

Perhaps use plt.annotate:

import numpy as np
import matplotlib.pyplot as plt

N = 10
data = np.random.random((N, 4))
labels = ['point{0}'.format(i) for i in range(N)]

plt.subplots_adjust(bottom = 0.1)
plt.scatter(
    data[:, 0], data[:, 1], marker='o', c=data[:, 2], s=data[:, 3] * 1500,
    cmap=plt.get_cmap('Spectral'))

for label, x, y in zip(labels, data[:, 0], data[:, 1]):
    plt.annotate(
        label,
        xy=(x, y), xytext=(-20, 20),
        textcoords='offset points', ha='right', va='bottom',
        bbox=dict(boxstyle='round,pad=0.5', fc='yellow', alpha=0.5),
        arrowprops=dict(arrowstyle = '->', connectionstyle='arc3,rad=0'))

plt.show()

enter image description here

Checking if float is an integer

stdlib float modf (float x, float *ipart) splits into two parts, check if return value (fractional part) == 0.

Regular expression for letters, numbers and - _

you can use

^[\w.-]+$

the + is to make sure it has at least 1 character. Need the ^ and $ to denote the begin and end, otherwise if the string has a match in the middle, such as @@@@xyz%%%% then it is still a match.

\w already includes alphabets (upper and lower case), numbers, and underscore. So the rest ., -, are just put into the "class" to match. The + means 1 occurrence or more.

P.S. thanks for the note in the comment

FileNotFoundError: [Errno 2] No such file or directory

Lets say we have a script in "c:\script.py" that contain :

result = open("index.html","r")
print(result.read())

Lets say that the index.html file is also in the same directory "c:\index.html" when i execute the script from cmd (or shell)

C:\Users\Amine>python c:\script.py

You will get error:

FileNotFoundError: [Errno 2] No such file or directory: 'index.html'

And that because "index.html" is not in working directory which is "C:\Users\Amine>". so in order to make it work you have to change the working directory

C:\python script.py

'<html><head></head><body></body></html>'

This is why is it preferable to use absolute path.

How can I format a nullable DateTime with ToString()?

You can use dt2.Value.ToString("format"), but of course that requires that dt2 != null, and that negates th use of a nullable type in the first place.

There are several solutions here, but the big question is: How do you want to format a null date?

Unresolved reference issue in PyCharm

Done in PyCharm 2019.3.1 Right-click on your src folder -> "Mark Directory as" -> Click-on "Excluded" and your src folder should be blue.

"Multiple definition", "first defined here" errors

The problem here is that you are including commands.c in commands.h before the function prototype. Therefore, the C pre-processor inserts the content of commands.c into commands.h before the function prototype. commands.c contains the function definition. As a result, the function definition ends up before than the function declaration causing the error.

The content of commands.h after the pre-processor phase looks like this:

#ifndef COMMANDS_H_
#define COMMANDS_H_

// function definition
void f123(){

}

// function declaration
void f123();

#endif /* COMMANDS_H_ */

This is an error because you can't declare a function after its definition in C. If you swapped #include "commands.c" and the function declaration the error shouldn't happen because, now, the function prototype comes before the function declaration.

However, including a .c file is a bad practice and should be avoided. A better solution for this problem would be to include commands.h in commands.c and link the compiled version of command to the main file. For example:

commands.h

#ifndef COMMANDS_H_
#define COMMANDS_H_

void f123(); // function declaration

#endif

commands.c

#include "commands.h"

void f123(){} // function definition

Search for string and get count in vi editor

I suggest doing:

  1. Search either with * to do a "bounded search" for what's under the cursor, or do a standard /pattern search.
  2. Use :%s///gn to get the number of occurrences. Or you can use :%s///n to get the number of lines with occurrences.

** I really with I could find a plug-in that would giving messaging of "match N of N1 on N2 lines" with every search, but alas.

Note: Don't be confused by the tricky wording of the output. The former command might give you something like 4 matches on 3 lines where the latter might give you 3 matches on 3 lines. While technically accurate, the latter is misleading and should say '3 lines match'. So, as you can see, there really is never any need to use the latter ('n' only) form. You get the same info, more clearly, and more by using the 'gn' form.

jQuery Datepicker close datepicker after selected date

There is another code that's works for me (jQuery).

_x000D_
_x000D_
$(".datepicker").datepicker({_x000D_
    format: "dd/mm/yyyy",_x000D_
    autoHide: true_x000D_
    })
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/datepicker/0.6.5/datepicker.js"></script>_x000D_
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/datepicker/0.6.5/datepicker.css" />_x000D_
Date: <input type="text" readonly="true" class="datepicker">
_x000D_
_x000D_
_x000D_

How to inspect Javascript Objects

Here is my object inspector that is more readable. Because the code takes to long to write down here you can download it at http://etto-aa-js.googlecode.com/svn/trunk/inspector.js

Use like this :

document.write(inspect(object));

Securely storing passwords for use in python script

I typically have a secrets.py that is stored separately from my other python scripts and is not under version control. Then whenever required, you can do from secrets import <required_pwd_var>. This way you can rely on the operating systems in-built file security system without re-inventing your own.

Using Base64 encoding/decoding is also another way to obfuscate the password though not completely secure

More here - Hiding a password in a python script (insecure obfuscation only)

Why is the use of alloca() not considered good practice?

Here's why:

char x;
char *y=malloc(1);
char *z=alloca(&x-y);
*z = 1;

Not that anyone would write this code, but the size argument you're passing to alloca almost certainly comes from some sort of input, which could maliciously aim to get your program to alloca something huge like that. After all, if the size isn't based on input or doesn't have the possibility to be large, why didn't you just declare a small, fixed-size local buffer?

Virtually all code using alloca and/or C99 vlas has serious bugs which will lead to crashes (if you're lucky) or privilege compromise (if you're not so lucky).

Create an ArrayList of unique values

Create an Arraylist of unique values

You could use Set.toArray() method.

A collection that contains no duplicate elements. More formally, sets contain no pair of elements e1 and e2 such that e1.equals(e2), and at most one null element. As implied by its name, this interface models the mathematical set abstraction.

http://docs.oracle.com/javase/6/docs/api/java/util/Set.html

How to perform a LEFT JOIN in SQL Server between two SELECT statements?

Try this:

SELECT user.userID, edge.TailUser, edge.Weight 
FROM user
LEFT JOIN edge ON edge.HeadUser = User.UserID
WHERE edge.HeadUser=5043

OR

AND edge.HeadUser=5043

instead of WHERE clausule.

Iterating through map in template

As Herman pointed out, you can get the index and element from each iteration.

{{range $index, $element := .}}{{$index}}
{{range $element}}{{.Value}}
{{end}}
{{end}}

Working example:

package main

import (
    "html/template"
    "os"
)

type EntetiesClass struct {
    Name string
    Value int32
}

// In the template, we use rangeStruct to turn our struct values
// into a slice we can iterate over
var htmlTemplate = `{{range $index, $element := .}}{{$index}}
{{range $element}}{{.Value}}
{{end}}
{{end}}`

func main() {
    data := map[string][]EntetiesClass{
        "Yoga": {{"Yoga", 15}, {"Yoga", 51}},
        "Pilates": {{"Pilates", 3}, {"Pilates", 6}, {"Pilates", 9}},
    }

    t := template.New("t")
    t, err := t.Parse(htmlTemplate)
    if err != nil {
        panic(err)
    }

    err = t.Execute(os.Stdout, data)
    if err != nil {
        panic(err)
    }

}

Output:

Pilates
3
6
9

Yoga
15
51

Playground: http://play.golang.org/p/4ISxcFKG7v

SQL Server Express CREATE DATABASE permission denied in database 'master'

A solution is presented here not exactly for your problem but exactly for the given error.

  1. Start --> All Programs --> Microsoft SQL Server 2005 --> Configuration Tools --> SQL Server Surface Area Configuration

  2. Add New Administrator

  3. Select 'Member of SQL Server SysAdmin role on SQLEXPRESS' and add it to right box.

  4. Click Ok.

Delete element in a slice

... is syntax for variadic arguments.

I think it is implemented by the complier using slice ([]Type), just like the function append :

func append(slice []Type, elems ...Type) []Type

when you use "elems" in "append", actually it is a slice([]type). So "a = append(a[:0], a[1:]...)" means "a = append(a[0:0], a[1:])"

a[0:0] is a slice which has nothing

a[1:] is "Hello2 Hello3"

This is how it works

Make view 80% width of parent in React Native

This is the way I got the solution. Simple and Sweet. Independent of Screen density:

export default class AwesomeProject extends Component {
    constructor(props){
        super(props);
        this.state = {text: ""}
    }
  render() {
    return (
       <View
          style={{
            flex: 1,
            backgroundColor: "#ececec",
            flexDirection: "column",
            justifyContent: "center",
            alignItems: "center"
          }}
        >
          <View style={{ padding: 10, flexDirection: "row" }}>
            <TextInput
              style={{ flex: 0.8, height: 40, borderWidth: 1 }}
              onChangeText={text => this.setState({ text })}
              placeholder="Text 1"
              value={this.state.text}
            />
          </View>
          <View style={{ padding: 10, flexDirection: "row" }}>
            <TextInput
              style={{ flex: 0.8, height: 40, borderWidth: 1 }}
              onChangeText={text => this.setState({ text })}
              placeholder="Text 2"
              value={this.state.text}
            />
          </View>
          <View style={{ padding: 10, flexDirection: "row" }}>
            <Button
              onPress={onButtonPress}
              title="Press Me"
              accessibilityLabel="See an Information"
            />
          </View>
        </View>
    );
  }
}

cordova Android requirements failed: "Could not find an installed version of Gradle"

Update your cordova to the latest version and the issue should be resolved. In case the issue not resolved please set the path in the environment variable (in case of Windows). Example: System Variable Value name GRADLE_HOME Value D:\Android\Android Studio\gradle\gradle-4.3.1 (please replace with your path)

ImportError: DLL load failed: The specified module could not be found

(I found this answer from a video: http://www.youtube.com/watch?v=xmvRF7koJ5E)

  1. Download msvcp71.dll and msvcr71.dll from the web.

  2. Save them to your C:\Windows\System32 folder.

  3. Save them to your C:\Windows\SysWOW64 folder as well (if you have a 64-bit operating system).

Now try running your code file in Python and it will load the graph in couple of seconds.

How to list all Git tags?

Try to make git tag it should be enough if not try to make git fetch then git tag.

Comparing two java.util.Dates to see if they are in the same day

You can avoid external dependencies and the performance hit of using Calendar by calculating the Julian Day Number for each of the dates and then comparing these:

public static boolean isSameDay(Date date1, Date date2) {

    // Strip out the time part of each date.
    long julianDayNumber1 = date1.getTime() / MILLIS_PER_DAY;
    long julianDayNumber2 = date2.getTime() / MILLIS_PER_DAY;

    // If they now are equal then it is the same day.
    return julianDayNumber1 == julianDayNumber2;
}

How do you handle a form change in jQuery?

Here is an elegant solution.

There is hidden property for each input element on the form that you can use to determine whether or not the value was changed. Each type of input has it's own property name. For example

  • for text/textarea it's defaultValue
  • for select it's defaultSelect
  • for checkbox/radio it's defaultChecked

Here is the example.

function bindFormChange($form) {

  function touchButtons() {
    var
      changed_objects = [],
      $observable_buttons = $form.find('input[type="submit"], button[type="submit"], button[data-object="reset-form"]');

    changed_objects = $('input:text, input:checkbox, input:radio, textarea, select', $form).map(function () {
      var
        $input = $(this),
        changed = false;

      if ($input.is('input:text') || $input.is('textarea') ) {
        changed = (($input).prop('defaultValue') != $input.val());
      }
      if (!changed && $input.is('select') ) {
        changed = !$('option:selected', $input).prop('defaultSelected');
      }
      if (!changed && $input.is('input:checkbox') || $input.is('input:radio') ) {
        changed = (($input).prop('defaultChecked') != $input.is(':checked'));
      }
      if (changed) {
        return $input.attr('id');
      }

    }).toArray();

    if (changed_objects.length) {
      $observable_buttons.removeAttr('disabled')   
    } else {
      $observable_buttons.attr('disabled', 'disabled');
    }
  };
  touchButtons();

  $('input, textarea, select', $form).each(function () {
    var $input = $(this);

    $input.on('keyup change', function () {
      touchButtons();
    });
  });

};

Now just loop thru the forms on the page and you should see submit buttons disabled by default and they will be activated ONLY if you indeed will change some input value on the form.

$('form').each(function () {
    bindFormChange($(this));
});

Implementation as a jQuery plugin is here https://github.com/kulbida/jmodifiable

Async await in linq select

I wanted to call Select(...) but ensure it ran in sequence because running in parallel would cause some other concurrency problems, so I ended up with this. I cannot call .Result because it will block the UI thread.

public static class TaskExtensions
{
    public static async Task<IEnumerable<TResult>> SelectInSequenceAsync<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, Task<TResult>> asyncSelector)
    {
        var result = new List<TResult>();
        foreach (var s in source)
        {
            result.Add(await asyncSelector(s));
        }
        
        return result;
    }
}

Usage:

var inputs = events.SelectInSequenceAsync(ev => ProcessEventAsync(ev))
                   .Where(i => i != null)
                   .ToList();

I am aware that Task.WhenAll is the way to go when we can run in parallel.

Comparing mongoose _id and strings

I faced exactly the same problem and i simply resolved the issue with the help of JSON.stringify() as follow:-

if (JSON.stringify(results.userId) === JSON.stringify(AnotherMongoDocument._id)) {
        console.log('This is never true');
}

Return multiple values from a function, sub or type?

Ideas :

  1. Use pass by reference (ByRef)
  2. Build a User Defined Type to hold the stuff you want to return, and return that.
  3. Similar to 2 - build a class to represent the information returned, and return objects of that class...

How to edit one specific row in Microsoft SQL Server Management Studio 2008?

The menu location seems to have changed to:

Query Designer --> Pane --> SQL

Android error while retrieving information from server 'RPC:s-5:AEC-0' in Google Play?

I've been having this problem too and I'm not sure why. Some people suggest removing your Google account and re-adding it and/or deleting the Play Store cache. I'm looking for more solutions, but it happens for all apps free, paid, whatever.

EDIT: just found this http://www.droid-life.com/2012/11/14/after-4-2-update-is-your-nexus-7-having-troubles-updating-apps-in-google-play/

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.

How to trigger a build only if changes happen on particular set of files

The Git plugin has an option (excluded region) to use regexes to determine whether to skip building based on whether files in the commit match the excluded region regex.

Unfortunately, the stock Git plugin does not have a "included region" feature at this time (1.15). However, someone posted patches on GitHub that work on Jenkins and Hudson that implement the feature you want.

It is a little work to build, but it works as advertised and has been extremely useful since one of my Git trees has multiple independent projects.

https://github.com/jenkinsci/git-plugin/pull/49

Update: The Git plugin (1.16) now has the 'included' region feature.

How to import multiple .csv files at once?

Using purrr and including file IDs as a column:

library(tidyverse)


p <- "my/directory"
files <- list.files(p, pattern="csv", full.names=TRUE) %>%
    set_names()
merged <- files %>% map_dfr(read_csv, .id="filename")

Without set_names(), .id= will use integer indicators, instead of actual file names.

If you then want just the short filename without the full path:

merged <- merged %>% mutate(filename=basename(filename))

Pandas convert dataframe to array of tuples

How about:

subset = data_set[['data_date', 'data_1', 'data_2']]
tuples = [tuple(x) for x in subset.to_numpy()]

for pandas < 0.24 use

tuples = [tuple(x) for x in subset.values]

How to install JDK 11 under Ubuntu?

Just updated older Ubuntu versions to openJDK 11
Actually I need it for Jenkins only and it seems to work fine.

Ubuntu 12.04 (Precise):
Download from openjdk-lts (11.0.4+11-1~12.04) precise
Files:
openjdk-11-jre-headless_11.0.4+11-1~12.04_amd64.deb
openjdk-11-jre_11.0.4+11-1~12.04_amd64.deb

Ubuntu 14.04 (Trusty):
Download from openjdk-lts (11.0.5+10-2ubuntu1~14.04) trusty
Files:
openjdk-11-jre-headless_11.0.5+10-2ubuntu1_14.04_amd64.deb
openjdk-11-jre_11.0.5+10-2ubuntu1_14.04_amd64.deb

Installation
After download I installed the files with Ubuntu Software Center ("headless" first!)
Then I selected the new version with sudo update-alternatives --config java

I didn't have to change any environment variables (like JAVA_HOME) - maybe Jenkins doesn't care about them...

Add a CSS class to <%= f.submit %>

By default, Rails 4 uses the 'value' attribute to control the visible button text, so to keep the markup clean I would use

<%= f.submit :value => "Visible Button Text", :class => 'class_name' %>

Preventing HTML and Script injections in Javascript

A one-liner:

var encodedMsg = $('<div />').text(message).html();

See it work:

https://jsfiddle.net/TimothyKanski/wnt8o12j/

Appending HTML string to the DOM

The idea is to use innerHTML on an intermediary element and then move all of its child nodes to where you really want them via appendChild.

var target = document.getElementById('test');
var str = '<p>Just some <span>text</span> here</p>';

var temp = document.createElement('div');
temp.innerHTML = str;
while (temp.firstChild) {
  target.appendChild(temp.firstChild);
}

This avoids wiping out any event handlers on div#test but still allows you to append a string of HTML.

Git ignore file for Xcode projects

gitignore.io: Create useful .gitignore files for your project

  • Example (macOS Objective-C Swift SwiftPackageManager Carthage)
  • Steps to use in Terminal (Refer to the YouTube Video)
    1. Create Git global config alias (One time only)

      git config --global alias.ignore '!gi() { curl -L -s https://www.gitignore.io/api/$@ ;}; gi'
      
    2. Enter the project directory

      cd <the project directory>
      
    3. Generate .gitignore file

      git ignore macOS,Objective-C,Swift,SwiftPackageManager,Carthage >.gitignore
      
    4. Add and commit .gitignore file

      git add .gitignore
      git commit -m "Add .gitignore file"
      

How do you return a JSON object from a Java Servlet

Just write a string to the output stream. You might set the MIME-type to text/javascript (edit: application/json is apparently officialer) if you're feeling helpful. (There's a small but nonzero chance that it'll keep something from messing it up someday, and it's a good practice.)

Printing tuple with string formatting in Python

For python 3

tup = (1,2,3)
print("this is a tuple %s" % str(tup))

Display Parameter(Multi-value) in Report

=Join(Parameters!Product.Label, vbcrfl) for new line

What is the difference between dynamic programming and greedy approach?

Based on Wikipedia's articles.

Greedy Approach

A greedy algorithm is an algorithm that follows the problem solving heuristic of making the locally optimal choice at each stage with the hope of finding a global optimum. In many problems, a greedy strategy does not in general produce an optimal solution, but nonetheless a greedy heuristic may yield locally optimal solutions that approximate a global optimal solution in a reasonable time.

We can make whatever choice seems best at the moment and then solve the subproblems that arise later. The choice made by a greedy algorithm may depend on choices made so far but not on future choices or all the solutions to the subproblem. It iteratively makes one greedy choice after another, reducing each given problem into a smaller one.

Dynamic programming

The idea behind dynamic programming is quite simple. In general, to solve a given problem, we need to solve different parts of the problem (subproblems), then combine the solutions of the subproblems to reach an overall solution. Often when using a more naive method, many of the subproblems are generated and solved many times. The dynamic programming approach seeks to solve each subproblem only once, thus reducing the number of computations: once the solution to a given subproblem has been computed, it is stored or "memo-ized": the next time the same solution is needed, it is simply looked up. This approach is especially useful when the number of repeating subproblems grows exponentially as a function of the size of the input.

Difference

Greedy choice property

We can make whatever choice seems best at the moment and then solve the subproblems that arise later. The choice made by a greedy algorithm may depend on choices made so far but not on future choices or all the solutions to the subproblem. It iteratively makes one greedy choice after another, reducing each given problem into a smaller one. In other words, a greedy algorithm never reconsiders its choices.

This is the main difference from dynamic programming, which is exhaustive and is guaranteed to find the solution. After every stage, dynamic programming makes decisions based on all the decisions made in the previous stage, and may reconsider the previous stage's algorithmic path to solution.

For example, let's say that you have to get from point A to point B as fast as possible, in a given city, during rush hour. A dynamic programming algorithm will look into the entire traffic report, looking into all possible combinations of roads you might take, and will only then tell you which way is the fastest. Of course, you might have to wait for a while until the algorithm finishes, and only then can you start driving. The path you will take will be the fastest one (assuming that nothing changed in the external environment).

On the other hand, a greedy algorithm will start you driving immediately and will pick the road that looks the fastest at every intersection. As you can imagine, this strategy might not lead to the fastest arrival time, since you might take some "easy" streets and then find yourself hopelessly stuck in a traffic jam.

Some other details...

In mathematical optimization, greedy algorithms solve combinatorial problems having the properties of matroids.

Dynamic programming is applicable to problems exhibiting the properties of overlapping subproblems and optimal substructure.

How to expire a cookie in 30 minutes using jQuery?

30 minutes is 30 * 60 * 1000 miliseconds. Add that to the current date to specify an expiration date 30 minutes in the future.

 var date = new Date();
 var minutes = 30;
 date.setTime(date.getTime() + (minutes * 60 * 1000));
 $.cookie("example", "foo", { expires: date });

How to convert a PIL Image into a numpy array?

Convert Numpy to PIL image and PIL to Numpy

import numpy as np
from PIL import Image

def pilToNumpy(img):
    return np.array(img)

def NumpyToPil(img):
    return Image.fromarray(img)

socket.emit() vs. socket.send()

socket.send is implemented for compatibility with vanilla WebSocket interface. socket.emit is feature of Socket.IO only. They both do the same, but socket.emit is a bit more convenient in handling messages.

starting file download with JavaScript

I'd suggest window.open() to open a popup window. If it's a download, there will be no window and you will get your file. If there is a 404 or something, the user will see it in a new window (hence, their work will not be bothered, but they will still get an error message).

Deleting rows with MySQL LEFT JOIN

If you are using "table as", then specify it to delete.

In the example i delete all table_1 rows which are do not exists in table_2.

DELETE t1 FROM `table_1` t1 LEFT JOIN `table_2` t2 ON t1.`id` = t2.`id` WHERE t2.`id` IS NULL

Is there a simple way to remove multiple spaces in a string?

This also seems to work:

while "  " in s:
    s = s.replace("  ", " ")

Where the variable s represents your string.

How to detect when a UIScrollView has finished scrolling

Just developed solution to detect when scrolling finished app-wide: https://gist.github.com/k06a/731654e3168277fb1fd0e64abc7d899e

It is based on idea of tracking changes of runloop modes. And perform blocks at least after 0.2 seconds after scrolling.

This is core idea for tracking runloop modes changes iOS10+:

- (void)tick {
    [[NSRunLoop mainRunLoop] performInModes:@[ UITrackingRunLoopMode ] block:^{
        [self tock];
    }];
}

- (void)tock {
    self.runLoopModeWasUITrackingAgain = YES;
    [[NSRunLoop mainRunLoop] performInModes:@[ NSDefaultRunLoopMode ] block:^{
        [self tick];
    }];
}

And solution for low deployment targets like iOS2+:

- (void)tick {
    [[NSRunLoop mainRunLoop] performSelector:@selector(tock) target:self argument:nil order:0 modes:@[ UITrackingRunLoopMode ]];
}

- (void)tock {
    self.runLoopModeWasUITrackingAgain = YES;
    [[NSRunLoop mainRunLoop] performSelector:@selector(tick) target:self argument:nil order:0 modes:@[ NSDefaultRunLoopMode ]];
}

Cycles in family tree software

Here's the problem with family trees: they are not trees. They are directed acyclic graphs or DAGs. If I understand the principles of the biology of human reproduction correctly, there will not be any cycles.

As far as I know, even the Christians accept marriages (and thus children) between cousins, which will turn the family tree into a family DAG.

The moral of the story is: choose the right data structures.

Good MapReduce examples

Map reduce is a framework that was developed to process massive amounts of data efficiently. For example, if we have 1 million records in a dataset, and it is stored in a relational representation - it is very expensive to derive values and perform any sort of transformations on these.

For Example In SQL, Given the Date of Birth, to find out How many people are of age > 30 for a million records would take a while, and this would only increase in order of magnitute when the complexity of the query increases. Map Reduce provides a cluster based implementation where data is processed in a distributed manner

Here is a wikipedia article explaining what map-reduce is all about

Another good example is Finding Friends via map reduce can be a powerful example to understand the concept, and a well used use-case.

Personally, found this link quite useful to understand the concept

Copying the explanation provided in the blog (In case the link goes stale)

Finding Friends

MapReduce is a framework originally developed at Google that allows for easy large scale distributed computing across a number of domains. Apache Hadoop is an open source implementation.

I'll gloss over the details, but it comes down to defining two functions: a map function and a reduce function. The map function takes a value and outputs key:value pairs. For instance, if we define a map function that takes a string and outputs the length of the word as the key and the word itself as the value then map(steve) would return 5:steve and map(savannah) would return 8:savannah. You may have noticed that the map function is stateless and only requires the input value to compute it's output value. This allows us to run the map function against values in parallel and provides a huge advantage. Before we get to the reduce function, the mapreduce framework groups all of the values together by key, so if the map functions output the following key:value pairs:

3 : the
3 : and
3 : you
4 : then
4 : what
4 : when
5 : steve
5 : where
8 : savannah
8 : research

They get grouped as:

3 : [the, and, you]
4 : [then, what, when]
5 : [steve, where]
8 : [savannah, research]

Each of these lines would then be passed as an argument to the reduce function, which accepts a key and a list of values. In this instance, we might be trying to figure out how many words of certain lengths exist, so our reduce function will just count the number of items in the list and output the key with the size of the list, like:

3 : 3
4 : 3
5 : 2
8 : 2

The reductions can also be done in parallel, again providing a huge advantage. We can then look at these final results and see that there were only two words of length 5 in our corpus, etc...

The most common example of mapreduce is for counting the number of times words occur in a corpus. Suppose you had a copy of the internet (I've been fortunate enough to have worked in such a situation), and you wanted a list of every word on the internet as well as how many times it occurred.

The way you would approach this would be to tokenize the documents you have (break it into words), and pass each word to a mapper. The mapper would then spit the word back out along with a value of 1. The grouping phase will take all the keys (in this case words), and make a list of 1's. The reduce phase then takes a key (the word) and a list (a list of 1's for every time the key appeared on the internet), and sums the list. The reducer then outputs the word, along with it's count. When all is said and done you'll have a list of every word on the internet, along with how many times it appeared.

Easy, right? If you've ever read about mapreduce, the above scenario isn't anything new... it's the "Hello, World" of mapreduce. So here is a real world use case (Facebook may or may not actually do the following, it's just an example):

Facebook has a list of friends (note that friends are a bi-directional thing on Facebook. If I'm your friend, you're mine). They also have lots of disk space and they serve hundreds of millions of requests everyday. They've decided to pre-compute calculations when they can to reduce the processing time of requests. One common processing request is the "You and Joe have 230 friends in common" feature. When you visit someone's profile, you see a list of friends that you have in common. This list doesn't change frequently so it'd be wasteful to recalculate it every time you visited the profile (sure you could use a decent caching strategy, but then I wouldn't be able to continue writing about mapreduce for this problem). We're going to use mapreduce so that we can calculate everyone's common friends once a day and store those results. Later on it's just a quick lookup. We've got lots of disk, it's cheap.

Assume the friends are stored as Person->[List of Friends], our friends list is then:

A -> B C D
B -> A C D E
C -> A B D E
D -> A B C E
E -> B C D

Each line will be an argument to a mapper. For every friend in the list of friends, the mapper will output a key-value pair. The key will be a friend along with the person. The value will be the list of friends. The key will be sorted so that the friends are in order, causing all pairs of friends to go to the same reducer. This is hard to explain with text, so let's just do it and see if you can see the pattern. After all the mappers are done running, you'll have a list like this:

For map(A -> B C D) :

(A B) -> B C D
(A C) -> B C D
(A D) -> B C D

For map(B -> A C D E) : (Note that A comes before B in the key)

(A B) -> A C D E
(B C) -> A C D E
(B D) -> A C D E
(B E) -> A C D E
For map(C -> A B D E) :

(A C) -> A B D E
(B C) -> A B D E
(C D) -> A B D E
(C E) -> A B D E
For map(D -> A B C E) :

(A D) -> A B C E
(B D) -> A B C E
(C D) -> A B C E
(D E) -> A B C E
And finally for map(E -> B C D):

(B E) -> B C D
(C E) -> B C D
(D E) -> B C D
Before we send these key-value pairs to the reducers, we group them by their keys and get:

(A B) -> (A C D E) (B C D)
(A C) -> (A B D E) (B C D)
(A D) -> (A B C E) (B C D)
(B C) -> (A B D E) (A C D E)
(B D) -> (A B C E) (A C D E)
(B E) -> (A C D E) (B C D)
(C D) -> (A B C E) (A B D E)
(C E) -> (A B D E) (B C D)
(D E) -> (A B C E) (B C D)

Each line will be passed as an argument to a reducer. The reduce function will simply intersect the lists of values and output the same key with the result of the intersection. For example, reduce((A B) -> (A C D E) (B C D)) will output (A B) : (C D) and means that friends A and B have C and D as common friends.

The result after reduction is:

(A B) -> (C D)
(A C) -> (B D)
(A D) -> (B C)
(B C) -> (A D E)
(B D) -> (A C E)
(B E) -> (C D)
(C D) -> (A B E)
(C E) -> (B D)
(D E) -> (B C)

Now when D visits B's profile, we can quickly look up (B D) and see that they have three friends in common, (A C E).

Loaded nib but the 'view' outlet was not set

I'd like to second Stephen J. Some times X Code does just get confused. I just had an experience where I had played around with the UI a lot, and had added and deleted outlets quite a few times. The outlets just would not wire-up any more. I never did figure out a specific reason (I had tried all the solutions above), and I just had to delete the NIB and recreate it from scratch, and in fact had to use a different name for the NIB before it would work. (XCode 4.6.1) Wasted a couple of hours on that.

Why is 22 the default port number for SFTP?

It's the default SSH port and SFTP is usually carried over an SSH tunnel.

"The breakpoint will not currently be hit. The source code is different from the original version." What does this mean?

Go to

  • Tools
    • Options
      • Debugging
        • General

Uncheck Require source files to exactly match the original version

Get immediate first child element

Both these will give you the first child node:

console.log(parentElement.firstChild); // or
console.log(parentElement.childNodes[0]);

If you need the first child that is an element node then use:

console.log(parentElement.children[0]);

Edit

Ah, I see your problem now; parentElement is an array.

If you know that getElementsByClassName will only return one result, which it seems you do, you should use [0] to dearray (yes, I made that word up) the element:

var parentElement = document.getElementsByClassName("uniqueClassName")[0];

Callback function for JSONP with jQuery AJAX

$.ajax({
        url: 'http://url.of.my.server/submit',
        dataType: "jsonp",
        jsonp: 'callback',
        jsonpCallback: 'jsonp_callback'
    });

jsonp is the querystring parameter name that is defined to be acceptable by the server while the jsonpCallback is the javascript function name to be executed at the client.
When you use such url:

url: 'http://url.of.my.server/submit?callback=?'

the question mark ? at the end instructs jQuery to generate a random function while the predfined behavior of the autogenerated function will just invoke the callback -the sucess function in this case- passing the json data as a parameter.

$.ajax({
        url: 'http://url.of.my.server/submit?callback=?',
        success: function (data, status) {
            mySurvey.closePopup();
        },
        error: function (xOptions, textStatus) {
            mySurvey.closePopup();
        }
    });


The same goes here if you are using $.getJSON with ? placeholder it will generate a random function while the predfined behavior of the autogenerated function will just invoke the callback:

$.getJSON('http://url.of.my.server/submit?callback=?',function(data){
//process data here
});

Scale the contents of a div by a percentage?

You can simply use the zoom property:

#myContainer{
    zoom: 0.5;
    -moz-transform: scale(0.5);
}

Where myContainer contains all the elements you're editing. This is supported in all major browsers.

jQuery ajax post file field

Try this...

<script type="text/javascript">
      $("#form_oferta").submit(function(event) 
      {
           var myData = $( form ).serialize(); 
           $.ajax({
                type: "POST", 
                contentType:attr( "enctype", "multipart/form-data" ),
                url: " URL Goes Here ",  
                data: myData,  
                success: function( data )  
                {
                     alert( data );
                }
           });
           return false;  
      });
</script>

Here the contentType is specified as multipart/form-data as we do in the form tag, this will work to upload simple file On server side you just need to write simple file upload code to handle this request with echoing message you want to show to user as a response.

Get the first element of each tuple in a list in Python

You can use list comprehension:

res_list = [i[0] for i in rows]

This should make the trick

log4j vs logback

Logback natively implements the SLF4J API. This means that if you are using logback, you are actually using the SLF4J API. You could theoretically use the internals of the logback API directly for logging, but that is highly discouraged. All logback documentation and examples on loggers are written in terms of the SLF4J API.

So by using logback, you'd be actually using SLF4J and if for any reason you wanted to switch back to log4j, you could do so within minutes by simply dropping slf4j-log4j12.jar onto your class path.

When migrating from logback to log4j, logback specific parts, specifically those contained in logback.xml configuration file would still need to be migrated to its log4j equivalent, i.e. log4j.properties. When migrating in the other direction, log4j configuration, i.e. log4j.properties, would need to be converted to its logback equivalent. There is an on-line tool for that. The amount of work involved in migrating configuration files is much less than the work required to migrate logger calls disseminated throughout all your software's source code and its dependencies.

C++ error: undefined reference to 'clock_gettime' and 'clock_settime'

Since glibc version 2.17, the library linking -lrt is no longer required.

The clock_* are now part of the main C library. You can see the change history of glibc 2.17 where this change was done explains the reason for this change:

+* The `clock_*' suite of functions (declared in <time.h>) is now available
+  directly in the main C library.  Previously it was necessary to link with
+  -lrt to use these functions.  This change has the effect that a
+  single-threaded program that uses a function such as `clock_gettime' (and
+  is not linked with -lrt) will no longer implicitly load the pthreads
+  library at runtime and so will not suffer the overheads associated with
+  multi-thread support in other code such as the C++ runtime library.

If you decide to upgrade glibc, then you can check the compatibility tracker of glibc if you are concerned whether there would be any issues using the newer glibc.

To check the glibc version installed on the system, run the command:

ldd --version

(Of course, if you are using old glibc (<2.17) then you will still need -lrt.)

Is there a way to 'uniq' by column?

Here is a very nifty way.

First format the content such that the column to be compared for uniqueness is a fixed width. One way of doing this is to use awk printf with a field/column width specifier ("%15s").

Now the -f and -w options of uniq can be used to skip preceding fields/columns and to specify the comparison width (column(s) width).

Here are three examples.

In the first example...

1) Temporarily make the column of interest a fixed width greater than or equal to the field's max width.

2) Use -f uniq option to skip the prior columns, and use the -w uniq option to limit the width to the tmp_fixed_width.

3) Remove trailing spaces from the column to "restore" it's width (assuming there were no trailing spaces beforehand).

printf "%s" "$str" \
| awk '{ tmp_fixed_width=15; uniq_col=8; w=tmp_fixed_width-length($uniq_col); for (i=0;i<w;i++) { $uniq_col=$uniq_col" "}; printf "%s\n", $0 }' \
| uniq -f 7 -w 15 \
| awk '{ uniq_col=8; gsub(/ */, "", $uniq_col); printf "%s\n", $0 }'

In the second example...

Create a new uniq column 1. Then remove it after the uniq filter has been applied.

printf "%s" "$str" \
| awk '{ uniq_col_1=4; printf "%15s %s\n", uniq_col_1, $0 }' \
| uniq -f 0 -w 15 \
| awk '{ $1=""; gsub(/^ */, "", $0); printf "%s\n", $0 }'

The third example is the same as the second, but for multiple columns.

printf "%s" "$str" \
| awk '{ uniq_col_1=4; uniq_col_2=8; printf "%5s %15s %s\n", uniq_col_1, uniq_col_2, $0 }' \
| uniq -f 0 -w 5 \
| uniq -f 1 -w 15 \
| awk '{ $1=$2=""; gsub(/^ */, "", $0); printf "%s\n", $0 }'

"Untrusted App Developer" message when installing enterprise iOS Application

On iOS 9:

Settings -> General -> Device Management -> Developer app / your Apple ID -> Add/remove trust there

'Source code does not match the bytecode' when debugging on a device

So I created an account just so I could help fix this problem that is plaguing a lot of people and where the fixes above aren't working.

If you get this error and nothing here helps. Try clicking the "Resume program play button" until the program finishes past the error. Then click in the console tab next to debug and read the red text.

I was getting that source code error even though my issue was trying to insert a value into a null Array. Step 1 Click the resume button

Step 2 Click the console tab and read the red text

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.

Using a global variable with a thread

A lock should be considered to use, such as threading.Lock. See lock-objects for more info.

The accepted answer CAN print 10 by thread1, which is not what you want. You can run the following code to understand the bug more easily.

def thread1(threadname):
    while True:
      if a % 2 and not a % 2:
          print "unreachable."

def thread2(threadname):
    global a
    while True:
        a += 1

Using a lock can forbid changing of a while reading more than one time:

def thread1(threadname):
    while True:
      lock_a.acquire()
      if a % 2 and not a % 2:
          print "unreachable."
      lock_a.release()

def thread2(threadname):
    global a
    while True:
        lock_a.acquire()
        a += 1
        lock_a.release()

If thread using the variable for long time, coping it to a local variable first is a good choice.

Parse usable Street Address, City, State, Zip from a string

I've been working in the address processing domain for about 5 years now, and there really is no silver bullet. The correct solution is going to depend on the value of the data. If it's not very valuable, throw it through a parser as the other answers suggest. If it's even somewhat valuable you'll definitely need to have a human evaluate/correct all the results of the parser. If you're looking for a fully automated, repeatable solution, you probably want to talk to a address correction vendor like Group1 or Trillium.

Can IntelliJ IDEA encapsulate all of the functionality of WebStorm and PHPStorm through plugins?

Definitely a great question. I've noted this also as a sub question of the choice for versions within IDEa that this link may help to address...

http://www.jetbrains.com/idea/features/editions_comparison_matrix.html

it as well potentially possesses a ground work for looking at your other IDE choices and the options they provide.

I'm thinking WebStorm is best for JavaScript and Git repo management, meaning the HTML5 CSS Cordova kinds of stacks, which is really where (I believe along with others) the future lies and energies should be focused now... but ya it depends on your needs, etc.

Anyway this tells that story too... http://www.jetbrains.com/products.html

ADB - Android - Getting the name of the current activity

You can use this command,

adb shell dumpsys activity

You can find current activity name in activity stack.

Output :-

 Sticky broadcasts:
 * Sticky action android.intent.action.BATTERY_CHANGED:
   Intent: act=android.intent.action.BATTERY_CHANGED flg=0x60000000
     Bundle[{icon-small=17302169, present=true, scale=100, level=50, technology=Li-ion, status=2, voltage=0, plugged=1, health=2, temperature=0}]
 * Sticky action android.net.thrott.THROTTLE_ACTION:
   Intent: act=android.net.thrott.THROTTLE_ACTION
     Bundle[{level=-1}]
 * Sticky action android.intent.action.NETWORK_SET_TIMEZONE:
   Intent: act=android.intent.action.NETWORK_SET_TIMEZONE flg=0x20000000
     Bundle[mParcelledData.dataSize=68]
 * Sticky action android.provider.Telephony.SPN_STRINGS_UPDATED:
   Intent: act=android.provider.Telephony.SPN_STRINGS_UPDATED flg=0x20000000
     Bundle[mParcelledData.dataSize=156]
 * Sticky action android.net.thrott.POLL_ACTION:
   Intent: act=android.net.thrott.POLL_ACTION
     Bundle[{cycleRead=0, cycleStart=1349893800000, cycleEnd=1352572200000, cycleWrite=0}]
 * Sticky action android.intent.action.SIM_STATE_CHANGED:
   Intent: act=android.intent.action.SIM_STATE_CHANGED flg=0x20000000
     Bundle[mParcelledData.dataSize=116]
 * Sticky action android.intent.action.SIG_STR:
   Intent: act=android.intent.action.SIG_STR flg=0x20000000
     Bundle[{EvdoSnr=-1, CdmaDbm=-1, GsmBitErrorRate=-1, CdmaEcio=-1, EvdoDbm=-1, GsmSignalStrength=7, EvdoEcio=-1, isGsm=true}]
 * Sticky action android.intent.action.SERVICE_STATE:
   Intent: act=android.intent.action.SERVICE_STATE flg=0x20000000
     Bundle[{cdmaRoamingIndicator=0, operator-numeric=310260, networkId=0, state=0, emergencyOnly=false, operator-alpha-short=Android, radioTechnology=3, manual=false, cssIndicator=false, operator-alpha-long=Android, systemId=0, roaming=false, cdmaDefaultRoamingIndicator=0}]
 * Sticky action android.net.conn.CONNECTIVITY_CHANGE:
   Intent: act=android.net.conn.CONNECTIVITY_CHANGE flg=0x30000000
     Bundle[{networkInfo=NetworkInfo: type: mobile[UMTS], state: CONNECTED/CONNECTED, reason: simLoaded, extra: internet, roaming: false, failover: false, isAvailable: true, reason=simLoaded, extraInfo=internet}]
 * Sticky action android.intent.action.NETWORK_SET_TIME:
   Intent: act=android.intent.action.NETWORK_SET_TIME flg=0x20000000
     Bundle[mParcelledData.dataSize=36]
 * Sticky action android.media.RINGER_MODE_CHANGED:
   Intent: act=android.media.RINGER_MODE_CHANGED flg=0x70000000
     Bundle[{android.media.EXTRA_RINGER_MODE=2}]
 * Sticky action android.intent.action.ANY_DATA_STATE:
   Intent: act=android.intent.action.ANY_DATA_STATE flg=0x20000000
     Bundle[{state=CONNECTED, apnType=*, iface=/dev/omap_csmi_tty1, apn=internet, reason=simLoaded}]

 Activity stack:
 * TaskRecord{450adb90 #22 A org.chanakyastocktipps.com}
   clearOnBackground=false numActivities=2 rootWasReset=false
   affinity=org.chanakyastocktipps.com
   intent={act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=org.chanakyastocktipps.com/.ui.SplashScreen}
   realActivity=org.chanakyastocktipps.com/.ui.SplashScreen
   lastActiveTime=15107753 (inactive for 4879s)
   * Hist #2: HistoryRecord{450d7ab0 org.chanakyastocktipps.com/.ui.Profile}
       packageName=org.chanakyastocktipps.com processName=org.chanakyastocktipps.com
       launchedFromUid=10046 app=ProcessRecord{44fa3450 1065:org.chanakyastocktipps.com/10046}
       Intent { cmp=org.chanakyastocktipps.com/.ui.Profile }
       frontOfTask=false task=TaskRecord{450adb90 #22 A org.chanakyastocktipps.com}
       taskAffinity=org.chanakyastocktipps.com
       realActivity=org.chanakyastocktipps.com/.ui.Profile
       base=/data/app/org.chanakyastocktipps.com-1.apk/data/app/org.chanakyastocktipps.com-1.apk data=/data/data/org.chanakyastocktipps.com
       labelRes=0x7f09000b icon=0x7f020065 theme=0x1030007
       stateNotNeeded=false componentSpecified=true isHomeActivity=false
       configuration={ scale=1.0 imsi=310/260 loc=en_US touch=3 keys=2/1/2 nav=3/1 orien=1 layout=18 uiMode=17 seq=3}
       resultTo=HistoryRecord{44f523c0 org.chanakyastocktipps.com/.ui.MainScreen} resultWho=null resultCode=4
       launchFailed=false haveState=false icicle=null
       state=RESUMED stopped=false delayedResume=false finishing=false
       keysPaused=false inHistory=true persistent=false launchMode=0
       fullscreen=true visible=true frozenBeforeDestroy=false thumbnailNeeded=false idle=true
       waitingVisible=false nowVisible=true
   * Hist #1: HistoryRecord{44f523c0 org.chanakyastocktipps.com/.ui.MainScreen}
       packageName=org.chanakyastocktipps.com processName=org.chanakyastocktipps.com
       launchedFromUid=10046 app=ProcessRecord{44fa3450 1065:org.chanakyastocktipps.com/10046}
       Intent { cmp=org.chanakyastocktipps.com/.ui.MainScreen }
       frontOfTask=true task=TaskRecord{450adb90 #22 A org.chanakyastocktipps.com}
       taskAffinity=org.chanakyastocktipps.com
       realActivity=org.chanakyastocktipps.com/.ui.MainScreen
       base=/data/app/org.chanakyastocktipps.com-1.apk/data/app/org.chanakyastocktipps.com-1.apk data=/data/data/org.chanakyastocktipps.com
       labelRes=0x7f09000b icon=0x7f020065 theme=0x1030007
       stateNotNeeded=false componentSpecified=true isHomeActivity=false
       configuration={ scale=1.0 imsi=310/260 loc=en_US touch=3 keys=2/1/2 nav=3/1 orien=1 layout=18 uiMode=17 seq=3}
       launchFailed=false haveState=true icicle=Bundle[mParcelledData.dataSize=1344]
       state=STOPPED stopped=true delayedResume=false finishing=false
       keysPaused=false inHistory=true persistent=false launchMode=0
       fullscreen=true visible=false frozenBeforeDestroy=false thumbnailNeeded=false idle=true
 * TaskRecord{450615a0 #2 A com.android.launcher}
   clearOnBackground=true numActivities=1 rootWasReset=false
   affinity=com.android.launcher
   intent={act=android.intent.action.MAIN cat=[android.intent.category.HOME] flg=0x10000000 cmp=com.android.launcher/com.android.launcher2.Launcher}
   realActivity=com.android.launcher/com.android.launcher2.Launcher
   lastActiveTime=12263090 (inactive for 7724s)
   * Hist #0: HistoryRecord{4505d838 com.android.launcher/com.android.launcher2.Launcher}
       packageName=com.android.launcher processName=com.android.launcher
       launchedFromUid=0 app=ProcessRecord{45062558 129:com.android.launcher/10025}
       Intent { act=android.intent.action.MAIN cat=[android.intent.category.HOME] flg=0x10000000 cmp=com.android.launcher/com.android.launcher2.Launcher }
       frontOfTask=true task=TaskRecord{450615a0 #2 A com.android.launcher}
       taskAffinity=com.android.launcher
       realActivity=com.android.launcher/com.android.launcher2.Launcher
       base=/system/app/Launcher2.apk/system/app/Launcher2.apk data=/data/data/com.android.launcher
       labelRes=0x7f0c0002 icon=0x7f020044 theme=0x7f0d0000
       stateNotNeeded=true componentSpecified=false isHomeActivity=true
       configuration={ scale=1.0 imsi=310/260 loc=en_US touch=3 keys=2/1/2 nav=3/1 orien=1 layout=18 uiMode=17 seq=3}
       launchFailed=false haveState=true icicle=Bundle[mParcelledData.dataSize=3608]
       state=STOPPED stopped=true delayedResume=false finishing=false
       keysPaused=false inHistory=true persistent=false launchMode=2
       fullscreen=true visible=false frozenBeforeDestroy=false thumbnailNeeded=false idle=true

 Running activities (most recent first):
   TaskRecord{450adb90 #22 A org.chanakyastocktipps.com}
     Run #2: HistoryRecord{450d7ab0 org.chanakyastocktipps.com/.ui.Profile}
     Run #1: HistoryRecord{44f523c0 org.chanakyastocktipps.com/.ui.MainScreen}
   TaskRecord{450615a0 #2 A com.android.launcher}
     Run #0: HistoryRecord{4505d838 com.android.launcher/com.android.launcher2.Launcher}

 mPausingActivity: null
 mResumedActivity: HistoryRecord{450d7ab0 org.chanakyastocktipps.com/.ui.Profile}
 mFocusedActivity: HistoryRecord{450d7ab0 org.chanakyastocktipps.com/.ui.Profile}
 mLastPausedActivity: HistoryRecord{44f523c0 org.chanakyastocktipps.com/.ui.MainScreen}

 mCurTask: 22

 Running processes (most recent first):
   App  #13: adj=vis  /F 45052120 119:com.android.inputmethod.latin/10003 (service)
             com.android.inputmethod.latin.LatinIME<=ProcessRecord{44ec2698 59:system/1000}
   PERS #12: adj=sys  /F 44ec2698 59:system/1000 (fixed)
   App  #11: adj=fore /F 44fa3450 1065:org.chanakyastocktipps.com/10046 (top-activity)
   App  #10: adj=bak  /B 44e7c4c0 299:com.svox.pico/10028 (bg-empty)
   App  # 9: adj=bak+1/B 450f7ef0 288:com.dreamreminder.org:feather_system_receiver/10057 (bg-empty)
   App  # 8: adj=bak+2/B 4503cc38 201:com.android.defcontainer/10010 (bg-empty)
   App  # 7: adj=home /B 45062558 129:com.android.launcher/10025 (home)
   App  # 6: adj=bak+3/B 450244d8 276:android.process.media/10002 (bg-empty)
   App  # 5: adj=bak+4/B 44f2b9b8 263:com.android.quicksearchbox/10012 (bg-empty)
   App  # 4: adj=bak+5/B 450beec0 257:com.android.protips/10007 (bg-empty)
   App  # 3: adj=bak+6/B 44ff37b8 270:com.android.music/10022 (bg-empty)
   PERS # 2: adj=core /F 45056818 124:com.android.phone/1001 (fixed)
   App  # 1: adj=bak+7/B 45080c38 238:com.dreamreminder.org/10057 (bg-empty)
   App  # 0: adj=empty/B 4507d030 229:com.android.email/10030 (bg-empty)

 PID mappings:
   PID #59: ProcessRecord{44ec2698 59:system/1000}
   PID #119: ProcessRecord{45052120 119:com.android.inputmethod.latin/10003}
   PID #124: ProcessRecord{45056818 124:com.android.phone/1001}
   PID #129: ProcessRecord{45062558 129:com.android.launcher/10025}
   PID #201: ProcessRecord{4503cc38 201:com.android.defcontainer/10010}
   PID #229: ProcessRecord{4507d030 229:com.android.email/10030}
   PID #238: ProcessRecord{45080c38 238:com.dreamreminder.org/10057}
   PID #257: ProcessRecord{450beec0 257:com.android.protips/10007}
   PID #263: ProcessRecord{44f2b9b8 263:com.android.quicksearchbox/10012}
   PID #270: ProcessRecord{44ff37b8 270:com.android.music/10022}
   PID #276: ProcessRecord{450244d8 276:android.process.media/10002}
   PID #288: ProcessRecord{450f7ef0 288:com.dreamreminder.org:feather_system_receiver/10057}
   PID #299: ProcessRecord{44e7c4c0 299:com.svox.pico/10028}
   PID #1065: ProcessRecord{44fa3450 1065:org.chanakyastocktipps.com/10046}

 mHomeProcess: ProcessRecord{45062558 129:com.android.launcher/10025}
 mConfiguration: { scale=1.0 imsi=310/260 loc=en_US touch=3 keys=2/1/2 nav=3/1 orien=1 layout=18 uiMode=17 seq=3}
 mConfigWillChange: false
 mSleeping=false mShuttingDown=false

Cross origin requests are only supported for HTTP but it's not cross-domain

If you’re working on a little front-end project and want to test it locally, you’d typically open it by pointing your local directory in the web browser, for instance entering file:///home/erick/mysuperproject/index.html in your URL bar. However, if your site is trying to load resources, even if they’re placed in your local directory, you might see warnings like this:

XMLHttpRequest cannot load file:///home/erick/mysuperproject/mylibrary.js. Cross origin requests are only supported for HTTP.

Chrome and other modern browsers have implemented security restrictions for Cross Origin Requests, which means that you cannot load anything through file:/// , you need to use http:// protocol at all times, even locally -due Same Origin policies. Simple as that, you’d need to mount a webserver to run your project there.

This is not the end of the world and there are many solutions out there, including the good old Apache (with VirtualHosts if you’re running several other projects), node.js with express, a Ruby server, etc. or simply modifying your browser settings.

However there’s a simpler and lightweight solution for the lazy ones. You can use Python’s SimpleHTTPServer. It comes already bundled with python so you don’t need to install or configure anything at all!

So cd to your project directory, for instance

1 cd /home/erick/mysuperproject and then simply use

1 python -m SimpleHTTPServer And that’s it, you’ll see this message in your terminal

1 Serving HTTP on 0.0.0.0 port 8000 ... So now you can go back to your browser and visit http://0.0.0.0:8000 with all your directory files served there. You can configure the port and other things, just see the documentation. But this simply trick works for me when I’m in a rush to test a new library or work out a new idea.

There you go, happy coding!

EDIT: In Python 3+, SimpleHTTPServer has been replaced with http.server. So In Python 3.3, for example, the following command is equivalent:

python -m http.server 8000

ORACLE: Updating multiple columns at once

It's perfectly possible to update multiple columns in the same statement, and in fact your code is doing it. So why does it seem that "INV_TOTAL is not updating, only the inv_discount"?

Because you're updating INV_TOTAL with INV_DISCOUNT, and the database is going to use the existing value of INV_DISCOUNT and not the one you change it to. So I'm afraid what you need to do is this:

UPDATE INVOICE
   SET INV_DISCOUNT = DISC1 * INV_SUBTOTAL
     , INV_TOTAL    = INV_SUBTOTAL - (DISC1 * INV_SUBTOTAL)     
WHERE INV_ID = I_INV_ID;

        

Perhaps that seems a bit clunky to you. It is, but the problem lies in your data model. Storing derivable values in the table, rather than deriving when needed, rarely leads to elegant SQL.

Proper way to assert type of variable in Python

You might want to try this example for version 2.6 of Python.

def my_print(text, begin, end):
    "Print text in UPPER between 'begin' and 'end' in lower."
    for obj in (text, begin, end):
        assert isinstance(obj, str), 'Argument of wrong type!'
    print begin.lower() + text.upper() + end.lower()

However, have you considered letting the function fail naturally instead?

DB2 Query to retrieve all table names for a given schema

On my iSeries I have to run this command from iNavigator:

select *
from QSYS2.SYSTABLES
where TABLE_SCHEMA
like 'SCHEMA_NAME'
and TYPE = 'T';

How to access the request body when POSTing using Node.js and Express?

This can be achieved without body-parser dependency as well, listen to request:data and request:end and return the response on end of request, refer below code sample. ref:https://nodejs.org/en/docs/guides/anatomy-of-an-http-transaction/#request-body

var express = require('express');
var app = express.createServer(express.logger());

app.post('/', function(request, response) {

    // push the data to body
    var body = [];
    request.on('data', (chunk) => {
      body.push(chunk);
    }).on('end', () => {
      // on end of data, perform necessary action
      body = Buffer.concat(body).toString();
      response.write(request.body.user);
      response.end();
    });
});

Update React component every second

Owing to changes in React V16 where componentWillReceiveProps() has been deprecated, this is the methodology that I use for updating a component. Notice that the below example is in Typescript and uses the static getDerivedStateFromProps method to get the initial state and updated state whenever the Props are updated.

    class SomeClass extends React.Component<Props, State> {
  static getDerivedStateFromProps(nextProps: Readonly<Props>): Partial<State> | null {
    return {
      time: nextProps.time
    };
  }

  timerInterval: any;

  componentDidMount() {
    this.timerInterval = setInterval(this.tick.bind(this), 1000);
  }

  tick() {
    this.setState({ time: this.props.time });
  }

  componentWillUnmount() {
    clearInterval(this.timerInterval);
  }

  render() {
    return <div>{this.state.time}</div>;
  }
}

How to place and center text in an SVG rectangle

An easy solution to center text horizontally and vertically in SVG:

  1. Set the position of the text to the absolute center of the element in which you want to center it:

    • If it's the parent, you could just do x="50%" y ="50%".
    • If it's another element, x would be the x of that element + half its width (and similar for y but with the height).
  2. Use the text-anchor property to center the text horizontally with the value middle:

    middle

    The rendered characters are aligned such that the geometric middle of the resulting rendered text is at the initial current text position.

  3. Use the dominant-baseline property to center the text vertically with the value middle (or depending on how you want it to look like, you may want to do central)

Here is a simple demo:

_x000D_
_x000D_
<svg width="200" height="100">_x000D_
  <rect x="0" y="0" width="200" height="100" stroke="red" stroke-width="3px" fill="white"/>_x000D_
  <text x="50%" y="50%" dominant-baseline="middle" text-anchor="middle">TEXT</text>    _x000D_
</svg>
_x000D_
_x000D_
_x000D_

How to check whether a pandas DataFrame is empty?

To see if a dataframe is empty, I argue that one should test for the length of a dataframe's columns index:

if len(df.columns) == 0: 1

Reason:

According to the Pandas Reference API, there is a distinction between:

  • an empty dataframe with 0 rows and 0 columns
  • an empty dataframe with rows containing NaN hence at least 1 column

Arguably, they are not the same. The other answers are imprecise in that df.empty, len(df), or len(df.index) make no distinction and return index is 0 and empty is True in both cases.

Examples

Example 1: An empty dataframe with 0 rows and 0 columns

In [1]: import pandas as pd
        df1 = pd.DataFrame()
        df1
Out[1]: Empty DataFrame
        Columns: []
        Index: []

In [2]: len(df1.index)  # or len(df1)
Out[2]: 0

In [3]: df1.empty
Out[3]: True

Example 2: A dataframe which is emptied to 0 rows but still retains n columns

In [4]: df2 = pd.DataFrame({'AA' : [1, 2, 3], 'BB' : [11, 22, 33]})
        df2
Out[4]:    AA  BB
        0   1  11
        1   2  22
        2   3  33

In [5]: df2 = df2[df2['AA'] == 5]
        df2
Out[5]: Empty DataFrame
        Columns: [AA, BB]
        Index: []

In [6]: len(df2.index)  # or len(df2)
Out[6]: 0

In [7]: df2.empty
Out[7]: True

Now, building on the previous examples, in which the index is 0 and empty is True. When reading the length of the columns index for the first loaded dataframe df1, it returns 0 columns to prove that it is indeed empty.

In [8]: len(df1.columns)
Out[8]: 0

In [9]: len(df2.columns)
Out[9]: 2

Critically, while the second dataframe df2 contains no data, it is not completely empty because it returns the amount of empty columns that persist.

Why it matters

Let's add a new column to these dataframes to understand the implications:

# As expected, the empty column displays 1 series
In [10]: df1['CC'] = [111, 222, 333]
         df1
Out[10]:    CC
         0 111
         1 222
         2 333
In [11]: len(df1.columns)
Out[11]: 1

# Note the persisting series with rows containing `NaN` values in df2
In [12]: df2['CC'] = [111, 222, 333]
         df2
Out[12]:    AA  BB   CC
         0 NaN NaN  111
         1 NaN NaN  222
         2 NaN NaN  333
In [13]: len(df2.columns)
Out[13]: 3

It is evident that the original columns in df2 have re-surfaced. Therefore, it is prudent to instead read the length of the columns index with len(pandas.core.frame.DataFrame.columns) to see if a dataframe is empty.

Practical solution

# New dataframe df
In [1]: df = pd.DataFrame({'AA' : [1, 2, 3], 'BB' : [11, 22, 33]})
        df
Out[1]:    AA  BB
        0   1  11
        1   2  22
        2   3  33

# This data manipulation approach results in an empty df
# because of a subset of values that are not available (`NaN`)
In [2]: df = df[df['AA'] == 5]
        df
Out[2]: Empty DataFrame
        Columns: [AA, BB]
        Index: []

# NOTE: the df is empty, BUT the columns are persistent
In [3]: len(df.columns)
Out[3]: 2

# And accordingly, the other answers on this page
In [4]: len(df.index)  # or len(df)
Out[4]: 0

In [5]: df.empty
Out[5]: True
# SOLUTION: conditionally check for empty columns
In [6]: if len(df.columns) != 0:  # <--- here
            # Do something, e.g. 
            # drop any columns containing rows with `NaN`
            # to make the df really empty
            df = df.dropna(how='all', axis=1)
        df
Out[6]: Empty DataFrame
        Columns: []
        Index: []

# Testing shows it is indeed empty now
In [7]: len(df.columns)
Out[7]: 0

Adding a new data series works as expected without the re-surfacing of empty columns (factually, without any series that were containing rows with only NaN):

In [8]: df['CC'] = [111, 222, 333]
         df
Out[8]:    CC
         0 111
         1 222
         2 333
In [9]: len(df.columns)
Out[9]: 1

What do raw.githubusercontent.com URLs represent?

raw.githubusercontent.com/username/repo-name/branch-name/path

Replace username with the username of the user that created the repo.

Replace repo-name with the name of the repo.

Replace branch-name with the name of the branch.

Replace path with the path to the file.

To reverse to go to GitHub.com:

GitHub.com/username/repo-name/directory-path/blob/branch-name/filename

How to sum all values in a column in Jaspersoft iReport Designer?

It is quite easy to solve your task. You should create and use a new variable for summing values of the "Doctor Payment" column.

In your case the variable can be declared like this:

<variable name="total" class="java.lang.Integer" calculation="Sum">
    <variableExpression><![CDATA[$F{payment}]]></variableExpression>
</variable>
  • the Calculation type is Sum;
  • the Reset type is Report;
  • the Variable expression is $F{payment}, where $F{payment} is the name of a field contains sum (Doctor Payment).

The working example.

CSV datasource:

doctor_id,payment
A1,123
B1,223
C2,234
D3,678
D1,343

The template:

<?xml version="1.0" encoding="UTF-8"?>
<jasperReport ...>
    <queryString>
        <![CDATA[]]>
    </queryString>
    <field name="doctor_id" class="java.lang.String"/>
    <field name="payment" class="java.lang.Integer"/>
    <variable name="total" class="java.lang.Integer" calculation="Sum">
        <variableExpression><![CDATA[$F{payment}]]></variableExpression>
    </variable>
    <columnHeader>
        <band height="20" splitType="Stretch">
            <staticText>
                <reportElement x="0" y="0" width="100" height="20"/>
                <box leftPadding="10"/>
                <textElement textAlignment="Center" verticalAlignment="Middle">
                    <font size="10" isBold="true" isItalic="true"/>
                </textElement>
                <text><![CDATA[Doctor ID]]></text>
            </staticText>
            <staticText>
                <reportElement x="100" y="0" width="100" height="20"/>
                <box leftPadding="10"/>
                <textElement textAlignment="Center" verticalAlignment="Middle">
                    <font size="10" isBold="true" isItalic="true"/>
                </textElement>
                <text><![CDATA[Doctor Payment]]></text>
            </staticText>
        </band>
    </columnHeader>
    <detail>
        <band height="20" splitType="Stretch">
            <textField>
                <reportElement x="0" y="0" width="100" height="20"/>
                <box leftPadding="10"/>
                <textElement/>
                <textFieldExpression><![CDATA[$F{doctor_id}]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement x="100" y="0" width="100" height="20"/>
                <box leftPadding="10"/>
                <textElement/>
                <textFieldExpression><![CDATA[$F{payment}]]></textFieldExpression>
            </textField>
        </band>
    </detail>
    <summary>
        <band height="20">
            <staticText>
                <reportElement x="0" y="0" width="100" height="20"/>
                <box leftPadding="10"/>
                <textElement>
                    <font isBold="true"/>
                </textElement>
                <text><![CDATA[Total]]></text>
            </staticText>
            <textField>
                <reportElement x="100" y="0" width="100" height="20"/>
                <box leftPadding="10"/>
                <textElement>
                    <font isBold="true" isItalic="true"/>
                </textElement>
                <textFieldExpression><![CDATA[$V{total}]]></textFieldExpression>
            </textField>
        </band>
    </summary>
</jasperReport>

The result will be:

Generated report via iReport's preview


You can find a lot of info in the JasperReports Ultimate Guide.

javax.el.PropertyNotFoundException: Property 'foo' not found on type com.example.Bean

javax.el.PropertyNotFoundException: Property 'foo' not found on type com.example.Bean

This literally means that the mentioned class com.example.Bean doesn't have a public (non-static!) getter method for the mentioned property foo. Note that the field itself is irrelevant here!

The public getter method name must start with get, followed by the property name which is capitalized at only the first letter of the property name as in Foo.

public Foo getFoo() {
    return foo;
}

You thus need to make sure that there is a getter method matching exactly the property name, and that the method is public (non-static) and that the method does not take any arguments and that it returns non-void. If you have one and it still doesn't work, then chances are that you were busy editing code forth and back without firmly cleaning the build, rebuilding the code and redeploying/restarting the application. You need to make sure that you have done so.

For boolean (not Boolean!) properties, the getter method name must start with is instead of get.

public boolean isFoo() {
    return foo;
}

Regardless of the type, the presence of the foo field itself is thus not relevant. It can have a different name, or be completely absent, or even be static. All of below should still be accessible by ${bean.foo}.

public Foo getFoo() {
    return bar;
}
public Foo getFoo() {
    return new Foo("foo");
}
public Foo getFoo() {
    return FOO_CONSTANT;
}

You see, the field is not what counts, but the getter method itself. Note that the property name itself should not be capitalized in EL. In other words, ${bean.Foo} won't ever work, it should be ${bean.foo}.

See also:

Mysql SELECT CASE WHEN something then return field

You are mixing the 2 different CASE syntaxes inappropriately.

Use this style (Searched)

  CASE  
  WHEN u.nnmu ='0' THEN mu.naziv_mesta
  WHEN u.nnmu ='1' THEN m.naziv_mesta
 ELSE 'GRESKA'
 END as mesto_utovara,

Or this style (Simple)

  CASE u.nnmu 
  WHEN '0' THEN mu.naziv_mesta
  WHEN '1' THEN m.naziv_mesta
 ELSE 'GRESKA'
 END as mesto_utovara,

Not This (Simple but with boolean search predicates)

  CASE u.nnmu 
  WHEN u.nnmu ='0' THEN mu.naziv_mesta
  WHEN u.nnmu ='1' THEN m.naziv_mesta
 ELSE 'GRESKA'
 END as mesto_utovara,

In MySQL this will end up testing whether u.nnmu is equal to the value of the boolean expression u.nnmu ='0' itself. Regardless of whether u.nnmu is 1 or 0 the result of the case expression itself will be 1

For example if nmu = '0' then (nnmu ='0') evaluates as true (1) and (nnmu ='1') evaluates as false (0). Substituting these into the case expression gives

 SELECT CASE  '0'
  WHEN 1 THEN '0'
  WHEN 0 THEN '1'
 ELSE 'GRESKA'
 END as mesto_utovara

if nmu = '1' then (nnmu ='0') evaluates as false (0) and (nnmu ='1') evaluates as true (1). Substituting these into the case expression gives

 SELECT CASE  '1'
  WHEN 0 THEN '0'
  WHEN 1 THEN '1'
 ELSE 'GRESKA'
 END as mesto_utovara