Programs & Examples On #Pax

0

#1292 - Incorrect date value: '0000-00-00'

The error is because of the sql mode which can be strict mode as per latest MYSQL 5.7 documentation.

For more information read this.

Hope it helps.

How to remove commits from a pull request

This is what helped me:

  1. Create a new branch with the existing one. Let's call the existing one branch_old and new as branch_new.

  2. Reset branch_new to a stable state, when you did not have any problem commit at all. For example, to put it at your local master's level do the following:

    git reset —hard master git push —force origin

  3. cherry-pick the commits from branch_old into branch_new

  4. git push

Send XML data to webservice using php curl

Previous anwser works fine. I would just add that you dont need to specify CURLOPT_POSTFIELDS as "xmlRequest=" . $input_xml to read your $_POST. You can use file_get_contents('php://input') to get the raw post data as plain XML.

Error LNK2019: Unresolved External Symbol in Visual Studio

When you have everything #included, an unresolved external symbol is often a missing * or & in the declaration or definition of a function.

How can I send cookies using PHP curl in addition to CURLOPT_COOKIEFILE?

I think the only cookie you need is JSESSIONID=xxx..

Also NEVER share your cookies, becasuse someone may access your personal data that way. Specially when the cookies are session. These cookies will stop working once you logout the site.

System.Collections.Generic.IEnumerable' does not contain any definition for 'ToList'

I was missing System.Data.Entity dll reference and problem was solved

Decorators with parameters?

Here is a slightly modified version of t.dubrownik's answer. Why?

  1. As a general template, you should return the return value from the original function.
  2. This changes the name of the function, which could affect other decorators / code.

So use @functools.wraps():

from functools import wraps

def decorator(argument):
    def real_decorator(function):
        @wraps(function)
        def wrapper(*args, **kwargs):
            funny_stuff()
            something_with_argument(argument)
            retval = function(*args, **kwargs)
            more_funny_stuff()
            return retval
        return wrapper
    return real_decorator

Python 2.6: Class inside a Class?

class Second:
    def __init__(self, data):
        self.data = data

class First:
    def SecondClass(self, data):
        return Second(data)

FirstClass = First()
SecondClass = FirstClass.SecondClass('now you see me')
print SecondClass.data

Tomcat started in Eclipse but unable to connect to http://localhost:8085/

Eclipse hooks Dynamic Web projects into tomcat and maintains it's own configuration but does not deploy the standard tomcat ROOT.war. As http://localhost:8085/ link returns 404 does indeed show that tomcat is up and running, just can't find a web app deployed to root.

By default, any deployed dynamic web projects use their project name as context root, so you should see http://localhost:8085/yourprojectname working properly, but check the Servers tab first to ensure that your web project has actually been deployed.

Hope that helps.

INSERT INTO @TABLE EXEC @query with SQL Server 2000

DECLARE @q nvarchar(4000)
SET @q = 'DECLARE @tmp TABLE (code VARCHAR(50), mount MONEY)
INSERT INTO @tmp
  (
    code,
    mount
  )
SELECT coa_code,
       amount
FROM   T_Ledger_detail

SELECT *
FROM   @tmp'

EXEC sp_executesql @q

If you want in dynamic query

What is a stack pointer used for in microprocessors?

The stack pointer holds the address to the top of the stack. A stack allows functions to pass arguments stored on the stack to each other, and to create scoped variables. Scope in this context means that the variable is popped of the stack when the stack frame is gone, and/or when the function returns. Without a stack, you would need to use explicit memory addresses for everything. That would make it impossible (or at least severely difficult) to design high-level programming languages for the architecture. Also, each CPU mode usually have its own banked stack pointer. So when exceptions occur (interrupts for example), the exception handler routine can use its own stack without corrupting the user process.

HTML display result in text (input) field?

Do you really want the result to come up in an input box? If not, consider a table with borders set to other than transparent and use

document.getElementById('sum').innerHTML = sum;

What's the difference between git clone --mirror and git clone --bare

The difference is that when using --mirror, all refs are copied as-is. This means everything: remote-tracking branches, notes, refs/originals/* (backups from filter-branch). The cloned repo has it all. It's also set up so that a remote update will re-fetch everything from the origin (overwriting the copied refs). The idea is really to mirror the repository, to have a total copy, so that you could for example host your central repo in multiple places, or back it up. Think of just straight-up copying the repo, except in a much more elegant git way.

The new documentation pretty much says all this:

--mirror

Set up a mirror of the source repository. This implies --bare. Compared to --bare, --mirror not only maps local branches of the source to local branches of the target, it maps all refs (including remote branches, notes etc.) and sets up a refspec configuration such that all these refs are overwritten by a git remote update in the target repository.

My original answer also noted the differences between a bare clone and a normal (non-bare) clone - the non-bare clone sets up remote tracking branches, only creating a local branch for HEAD, while the bare clone copies the branches directly.

Suppose origin has a few branches (master (HEAD), next, pu, and maint), some tags (v1, v2, v3), some remote branches (devA/master, devB/master), and some other refs (refs/foo/bar, refs/foo/baz, which might be notes, stashes, other devs' namespaces, who knows).

  • git clone origin-url (non-bare): You will get all of the tags copied, a local branch master (HEAD) tracking a remote branch origin/master, and remote branches origin/next, origin/pu, and origin/maint. The tracking branches are set up so that if you do something like git fetch origin, they'll be fetched as you expect. Any remote branches (in the cloned remote) and other refs are completely ignored.

  • git clone --bare origin-url: You will get all of the tags copied, local branches master (HEAD), next, pu, and maint, no remote tracking branches. That is, all branches are copied as is, and it's set up completely independent, with no expectation of fetching again. Any remote branches (in the cloned remote) and other refs are completely ignored.

  • git clone --mirror origin-url: Every last one of those refs will be copied as-is. You'll get all the tags, local branches master (HEAD), next, pu, and maint, remote branches devA/master and devB/master, other refs refs/foo/bar and refs/foo/baz. Everything is exactly as it was in the cloned remote. Remote tracking is set up so that if you run git remote update all refs will be overwritten from origin, as if you'd just deleted the mirror and recloned it. As the docs originally said, it's a mirror. It's supposed to be a functionally identical copy, interchangeable with the original.

How can I declare enums using java

public enum NewEnum {
   ONE("test"),
   TWO("test");

   private String s;

   private NewEnum(String s) {
      this.s = s);
   }

    public String getS() {
        return this.s;
    }
}

Find a private field with Reflection?

I use this method personally

if (typeof(Foo).GetFields(BindingFlags.NonPublic | BindingFlags.Instance).Any(c => c.GetCustomAttributes(typeof(SomeAttribute), false).Any()))
{ 
    // do stuff
}

How to create war files

A war file is simply a jar file with a war extension, but what makes it work is how the contents is actually structured.

The J2EE/Java EE tutorial can be a start:

http://java.sun.com/j2ee/tutorial/1_3-fcs/doc/WebComponents3.html

And the Servlet specification contains the gory details:

http://java.sun.com/products/servlet/download.html

If you create a new web project in Eclipse (I am referring to the Java EE version), the structure is created for you and you can also tell it where your Appserver is installed and it will deploy and start the application for you.

Using the "Export->WAR file" option will let you save the war file.

Setting public class variables

Inside class Testclass:

public function __construct($new_value)
{
    $this->testvar = $new_value;
}

CSS endless rotation animation

_x000D_
_x000D_
@-webkit-keyframes rotating /* Safari and Chrome */ {_x000D_
  from {_x000D_
    -webkit-transform: rotate(0deg);_x000D_
    -o-transform: rotate(0deg);_x000D_
    transform: rotate(0deg);_x000D_
  }_x000D_
  to {_x000D_
    -webkit-transform: rotate(360deg);_x000D_
    -o-transform: rotate(360deg);_x000D_
    transform: rotate(360deg);_x000D_
  }_x000D_
}_x000D_
@keyframes rotating {_x000D_
  from {_x000D_
    -ms-transform: rotate(0deg);_x000D_
    -moz-transform: rotate(0deg);_x000D_
    -webkit-transform: rotate(0deg);_x000D_
    -o-transform: rotate(0deg);_x000D_
    transform: rotate(0deg);_x000D_
  }_x000D_
  to {_x000D_
    -ms-transform: rotate(360deg);_x000D_
    -moz-transform: rotate(360deg);_x000D_
    -webkit-transform: rotate(360deg);_x000D_
    -o-transform: rotate(360deg);_x000D_
    transform: rotate(360deg);_x000D_
  }_x000D_
}_x000D_
.rotating {_x000D_
  -webkit-animation: rotating 2s linear infinite;_x000D_
  -moz-animation: rotating 2s linear infinite;_x000D_
  -ms-animation: rotating 2s linear infinite;_x000D_
  -o-animation: rotating 2s linear infinite;_x000D_
  animation: rotating 2s linear infinite;_x000D_
}
_x000D_
<div _x000D_
  class="rotating"_x000D_
  style="width: 100px; height: 100px; line-height: 100px; text-align: center;" _x000D_
 >Rotate</div>
_x000D_
_x000D_
_x000D_

Set opacity of background image without affecting child elements

If you have to set the opacity only to the bullet, why don't you set the alpha channel directly into the image? By the way I don't think there is a way to set the opacity to a background image via css without changing the opacity of the whole element (and its children too).

Query an XDocument for elements by name at any depth

(Code and Instructions is for C# and may need to be slightly altered for other languages)

This example works perfect if you want to read from a Parent Node that has many children, for example look at the following XML;

<?xml version="1.0" encoding="UTF-8"?> 
<emails>
    <emailAddress>[email protected]</emailAddress>
    <emailAddress>[email protected]</emailAddress>
    <emailAddress>rgreen@set_ig.ca</emailAddress> 
</emails>

Now with this code below (keeping in mind that the XML File is stored in resources (See the links at end of snippet for help on resources) You can obtain each email address within the "emails" tag.

XDocument doc = XDocument.Parse(Properties.Resources.EmailAddresses);

var emailAddresses = (from emails in doc.Descendants("emailAddress")
                      select emails.Value);

foreach (var email in emailAddresses)
{
    //Comment out if using WPF or Windows Form project
    Console.WriteLine(email.ToString());

   //Remove comment if using WPF or Windows Form project
   //MessageBox.Show(email.ToString());
}

Results

  1. [email protected]
  2. [email protected]
  3. rgreen@set_ig.ca

Note: For Console Application and WPF or Windows Forms you must add the "using System.Xml.Linq;" Using directive at the top of your project, for Console you will also need to add a reference to this namespace before adding the Using directive. Also for Console there will be no Resource file by default under the "Properties folder" so you have to manually add the Resource file. The MSDN articles below, explain this in detail.

Adding and Editing Resources

How to: Add or Remove Resources

How do I use this JavaScript variable in HTML?

You can create an element with an id and then assign that length value to that element.

_x000D_
_x000D_
var name = prompt("What's your name?");_x000D_
var lengthOfName = name.length_x000D_
document.getElementById('message').innerHTML = lengthOfName;
_x000D_
<p id='message'></p>
_x000D_
_x000D_
_x000D_

How to use data-binding with Fragment

If you are using ViewModel and LiveData This is the sufficient syntax

Kotlin Syntax:

override fun onCreateView(
    inflater: LayoutInflater,
    container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {
    return MartianDataBinding.inflate(
        inflater,
        container,
        false
    ).apply {
        lifecycleOwner = viewLifecycleOwner
        vm = viewModel    // Attach your view model here
    }.root
}

"R cannot be resolved to a variable"?

Sooo many different possible solutions! For me, I found that Eclipse had created the faulty file in the wrong package. I fixed it by moving it into the same package as the R.java file.

How to find EOF through fscanf?

fscanf - "On success, the function returns the number of items successfully read. This count can match the expected number of readings or be less -even zero- in the case of a matching failure. In the case of an input failure before any data could be successfully read, EOF is returned."

So, instead of doing nothing with the return value like you are right now, you can check to see if it is == EOF.

You should check for EOF when you call fscanf, not check the array slot for EOF.

How do I create and read a value from cookie?

The chrome team has proposed a new way of managing cookies asynchronous with the Cookie Storage API (available in Google Chrome starting from version 87): https://wicg.github.io/cookie-store/

Use it already today with a polyfill for the other browsers: https://github.com/mkay581/cookie-store

// load polyfill
import 'cookie-store';

// set a cookie
await cookieStore.set('name', 'value');
// get a cookie
const savedValue = await cookieStore.get('name');

How do I shutdown, restart, or log off Windows via a bat file?

I'm late to the party, but did not see this answer yet. When you don't want to use a batch file or type the command. You can just set focus to the desktop and then use Alt + F4.

Windows will ask you what you want to do, select shutdown or restart.

For screenshots and even a video, see: https://tinkertry.com/how-to-shutdown-or-restart-windows-over-rdp

How to pass a view's onClick event to its parent on Android?

Sometime only this helps:

View child = parent.findViewById(R.id.btnMoreText);
    child.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            View parent = (View) v.getParent();
            parent.performClick();
        }
    });

Another variant, works not always:

child.setOnClickListener(null);

How to sort a collection by date in MongoDB?

db.getCollection('').find({}).sort({_id:-1}) 

This will sort your collection in descending order based on the date of insertion

Focus Input Box On Load

There are two parts to your question.

1) How to focus an input on page load?

You can just add the autofocus attribute to the input.

<input id="myinputbox" type="text" autofocus>

However, this might not be supported in all browsers, so we can use javascript.

window.onload = function() {
  var input = document.getElementById("myinputbox").focus();
}

2) How to place cursor at the end of the input text?

Here's a non-jQuery solution with some borrowed code from another SO answer.

function placeCursorAtEnd() {
  if (this.setSelectionRange) {
    // Double the length because Opera is inconsistent about 
    // whether a carriage return is one character or two.
    var len = this.value.length * 2;
    this.setSelectionRange(len, len);
  } else {
    // This might work for browsers without setSelectionRange support.
    this.value = this.value;
  }

  if (this.nodeName === "TEXTAREA") {
    // This will scroll a textarea to the bottom if needed
    this.scrollTop = 999999;
  }
};

window.onload = function() {
  var input = document.getElementById("myinputbox");

  if (obj.addEventListener) {
    obj.addEventListener("focus", placeCursorAtEnd, false);
  } else if (obj.attachEvent) {
    obj.attachEvent('onfocus', placeCursorAtEnd);
  }

  input.focus();
}

Here's an example of how I would accomplish this with jQuery.

<input type="text" autofocus>

<script>
$(function() {
  $("[autofocus]").on("focus", function() {
    if (this.setSelectionRange) {
      var len = this.value.length * 2;
      this.setSelectionRange(len, len);
    } else {
      this.value = this.value;
    }
    this.scrollTop = 999999;
  }).focus();
});
</script>

CSS Display an Image Resized and Cropped

You can use Kodem's Image Resize Service. You can resize any image with just a http call. Can be used casually in the browser or used in your production app.

  • Upload the image somewhere you prefer (S3, imgur etc.)
  • Plug it into your dedicated API url (from our dashboard)

IsNothing versus Is Nothing

You should absolutely avoid using IsNothing()

Here are 4 reasons from the article IsNothing() VS Is Nothing

  1. Most importantly, IsNothing(object) has everything passed to it as an object, even value types! Since value types cannot be Nothing, it’s a completely wasted check.
    Take the following example:

    Dim i As Integer
    If IsNothing(i) Then
       ' Do something 
    End If
    

    This will compile and run fine, whereas this:

    Dim i As Integer
    If i Is Nothing Then
        '   Do something 
    End If
    

    Will not compile, instead the compiler will raise the error:

    'Is' operator does not accept operands of type 'Integer'.
    Operands must be reference or nullable types.

  2. IsNothing(object) is actually part of part of the Microsoft.VisualBasic.dll.
    This is undesirable as you have an unneeded dependency on the VisualBasic library.

  3. Its slow - 33.76% slower in fact (over 1000000000 iterations)!

  4. Perhaps personal preference, but IsNothing() reads like a Yoda Condition. When you look at a variable you're checking it's state, with it as the subject of your investigation.

    i.e. does it do x? --- NOT Is xing a property of it?

    So I think If a IsNot Nothing reads better than If Not IsNothing(a)

AVD Manager - No system image installed for this target

you should android sdk manager install 4.2 api 17 -> ARM EABI v7a System Image

if not installed ARM EABI v7a System Image, you should install all.

Show hide divs on click in HTML and CSS without jQuery

Using display:none is not SEO-friendly. The following way allows the hidden content to be searchable. Adding the transition-delay ensures any links included in the hidden content is clickable.

.collapse > p{
cursor: pointer;
display: block;
}

.collapse:focus{
outline: none;
}

.collapse > div {
height: 0;
width: 0;
overflow: hidden;
transition-delay: 0.3s;
}

.collapse:focus div{
display: block; 
height: 100%;
width: 100%;
overflow: auto;
}

<div class="collapse" tabindex="1">
<p>Question 1</p>
<div>
  <p>Visit <a href="https://stackoverflow.com/">Stack Overflow</a></p>
</div>
</div>
<div class="collapse" tabindex="2">
<p>Question 2</p>
<div>
  <p>Visit <a href="https://stackoverflow.com/">Stack Overflow</a></p>
</div>
</div> 

How can I list ALL grants a user received?

The most comprehensive and reliable method I know is still by using DBMS_METADATA:

select dbms_metadata.get_granted_ddl( 'SYSTEM_GRANT', :username ) from dual;
select dbms_metadata.get_granted_ddl( 'OBJECT_GRANT', :username ) from dual;
select dbms_metadata.get_granted_ddl( 'ROLE_GRANT', :username ) from dual;

(username must be written all uppercase)

Interesting answers though.

Change GridView row color based on condition

Create GridView1_RowDataBound event for your GridView.

//Check if it is not header or footer row
if (e.Row.RowType == DataControlRowType.DataRow)
{
    //Check your condition here
    If(Condition True)
    {
        e.Row.BackColor = Drawing.Color.Red // This will make row back color red
    }
}

Eliminating duplicate values based on only one column of the table

I solve such queries using this pattern:

SELECT *
FROM t
WHERE t.field=(
  SELECT MAX(t.field) 
  FROM t AS t0 
  WHERE t.group_column1=t0.group_column1
    AND t.group_column2=t0.group_column2 ...)

That is it will select records where the value of a field is at its max value. To apply it to your query I used the common table expression so that I don't have to repeat the JOIN twice:

WITH site_history AS (
  SELECT sites.siteName, sites.siteIP, history.date
  FROM sites
  JOIN history USING (siteName)
)
SELECT *
FROM site_history h
WHERE date=(
  SELECT MAX(date) 
  FROM site_history h0 
  WHERE h.siteName=h0.siteName)
ORDER BY siteName

It's important to note that it works only if the field we're calculating the maximum for is unique. In your example the date field should be unique for each siteName, that is if the IP can't be changed multiple times per millisecond. In my experience this is commonly the case otherwise you don't know which record is the newest anyway. If the history table has an unique index for (site, date), this query is also very fast, index range scan on the history table scanning just the first item can be used.

How to print matched regex pattern using awk?

Off topic, this can be done using the grep also, just posting it here in case if anyone is looking for grep solution

echo 'xxx yyy zzze ' | grep -oE 'yyy'

How can I loop through all rows of a table? (MySQL)

Since the suggestion of a loop implies the request for a procedure type solution. Here is mine.

Any query which works on any single record taken from a table can be wrapped in a procedure to make it run through each row of a table like so:

First delete any existing procedure with the same name, and change the delimiter so your SQL doesn't try to run each line as you're trying to write the procedure.

DROP PROCEDURE IF EXISTS ROWPERROW;
DELIMITER ;;

Then here's the procedure as per your example (table_A and table_B used for clarity)

CREATE PROCEDURE ROWPERROW()
BEGIN
DECLARE n INT DEFAULT 0;
DECLARE i INT DEFAULT 0;
SELECT COUNT(*) FROM table_A INTO n;
SET i=0;
WHILE i<n DO 
  INSERT INTO table_B(ID, VAL) SELECT (ID, VAL) FROM table_A LIMIT i,1;
  SET i = i + 1;
END WHILE;
End;
;;

Then dont forget to reset the delimiter

DELIMITER ;

And run the new procedure

CALL ROWPERROW();

You can do whatever you like at the "INSERT INTO" line which I simply copied from your example request.

Note CAREFULLY that the "INSERT INTO" line used here mirrors the line in the question. As per the comments to this answer you need to ensure that your query is syntactically correct for which ever version of SQL you are running.

In the simple case where your ID field is incremented and starts at 1 the line in the example could become:

INSERT INTO table_B(ID, VAL) VALUES(ID, VAL) FROM table_A WHERE ID=i;

Replacing the "SELECT COUNT" line with

SET n=10;

Will let you test your query on the first 10 record in table_A only.

One last thing. This process is also very easy to nest across different tables and was the only way I could carry out a process on one table which dynamically inserted different numbers of records into a new table from each row of a parent table.

If you need it to run faster then sure try to make it set based, if not then this is fine. You could also rewrite the above in cursor form but it may not improve performance. eg:

DROP PROCEDURE IF EXISTS cursor_ROWPERROW;
DELIMITER ;;

CREATE PROCEDURE cursor_ROWPERROW()
BEGIN
  DECLARE cursor_ID INT;
  DECLARE cursor_VAL VARCHAR;
  DECLARE done INT DEFAULT FALSE;
  DECLARE cursor_i CURSOR FOR SELECT ID,VAL FROM table_A;
  DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
  OPEN cursor_i;
  read_loop: LOOP
    FETCH cursor_i INTO cursor_ID, cursor_VAL;
    IF done THEN
      LEAVE read_loop;
    END IF;
    INSERT INTO table_B(ID, VAL) VALUES(cursor_ID, cursor_VAL);
  END LOOP;
  CLOSE cursor_i;
END;
;;

Remember to declare the variables you will use as the same type as those from the queried tables.

My advise is to go with setbased queries when you can, and only use simple loops or cursors if you have to.

Showing line numbers in IPython/Jupyter Notebooks

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

The menu looks like this

Move_uploaded_file() function is not working

Try using copy() function instead of move_uploaded_file(). It worked for me.

copy($_FILES['file']['tmp_name'], $path);

How do I remove the space between inline/inline-block elements?

Two more options based on CSS Text Module Level 3 (instead of white-space-collapsing:discard which had been dropped from the spec draft):

  • word-spacing: -100%;

In theory, it should do exactly what is needed — shorten whitespaces between 'words' by the 100% of the space character width, i.e. to zero. But seems not to work anywhere, unfortunately, and this feature is marked 'at risk' (it can be dropped from the specification, too).

  • word-spacing: -1ch;

It shortens the inter-word spaces by the width of the digit '0'. In a monospace font it should be exactly equal to the width of the space character (and any other character as well). This works in Firefox 10+, Chrome 27+, and almost works in Internet Explorer 9+.

Fiddle

Invoke(Delegate)

this.Invoke(delegate) make sure that you are calling the delegate the argument to this.Invoke() on main thread/created thread.

I can say a Thumb rule don't access your form controls except from main thread.

May be the following lines make sense for using Invoke()

    private void SetText(string text)
    {
        // InvokeRequired required compares the thread ID of the
        // calling thread to the thread ID of the creating thread.
        // If these threads are different, it returns true.
        if (this.textBox1.InvokeRequired)
        {   
            SetTextCallback d = new SetTextCallback(SetText);
            this.Invoke(d, new object[] { text });
        }
        else
        {
            this.textBox1.Text = text;
        }
    }

There are situations though you create a Threadpool thread(i.e worker thread) it will run on main thread. It won't create a new thread coz main thread is available for processing further instructions. So First investigate whether the current running thread is main thread using this.InvokeRequired if returns true the current code is running on worker thread so call this.Invoke(d, new object[] { text });

else directly update the UI control(Here you are guaranteed that you are running the code on main thread.)

Converting an object to a string

If you only care about strings, objects, and arrays:

function objectToString (obj) {
        var str = '';
        var i=0;
        for (var key in obj) {
            if (obj.hasOwnProperty(key)) {
                if(typeof obj[key] == 'object')
                {
                    if(obj[key] instanceof Array)
                    {
                        str+= key + ' : [ ';
                        for(var j=0;j<obj[key].length;j++)
                        {
                            if(typeof obj[key][j]=='object') {
                                str += '{' + objectToString(obj[key][j]) + (j > 0 ? ',' : '') + '}';
                            }
                            else
                            {
                                str += '\'' + obj[key][j] + '\'' + (j > 0 ? ',' : ''); //non objects would be represented as strings
                            }
                        }
                        str+= ']' + (i > 0 ? ',' : '')
                    }
                    else
                    {
                        str += key + ' : { ' + objectToString(obj[key]) + '} ' + (i > 0 ? ',' : '');
                    }
                }
                else {
                    str +=key + ':\'' + obj[key] + '\'' + (i > 0 ? ',' : '');
                }
                i++;
            }
        }
        return str;
    }

Converting a string to JSON object

Simply use eval function.

var myJson = eval(theJsibStr);

Is there a way to know your current username in mysql?

Try to run either

SELECT USER();

or

SELECT CURRENT_USER();

It can sometimes be different, USER() will return by which login you attempted to authenticate and CURRENT_USER() will return how you were actually allowed to authenticate.

Searching a list of objects in Python

You should add a __eq__ and a __hash__ method to your Data class, it could check if the __dict__ attributes are equal (same properties) and then if their values are equal, too.

If you did that, you can use

test = Data()
test.n = 5

found = test in myList

The in keyword checks if test is in myList.

If you only want to a a n property in Data you could use:

class Data(object):
    __slots__ = ['n']
    def __init__(self, n):
        self.n = n
    def __eq__(self, other):
        if not isinstance(other, Data):
            return False
        if self.n != other.n:
            return False
        return True
    def __hash__(self):
        return self.n

    myList = [ Data(1), Data(2), Data(3) ]
    Data(2) in myList  #==> True
    Data(5) in myList  #==> False

Can I save input from form to .txt in HTML, using JAVASCRIPT/jQuery, and then use it?

Or this will work too the same way but without a save as choice:

<!DOCTYPE html>
<html>
<head>


<script type='text/javascript'>//<![CDATA[
window.onload=function(){
(function () {
var textFile = null,
  makeTextFile = function (text) {
    var data = new Blob([text], {type: 'text/plain'});

    // If we are replacing a previously generated file we need to
    // manually revoke the object URL to avoid memory leaks.
    if (textFile !== null) {
      window.URL.revokeObjectURL(textFile);
    }

    textFile = window.URL.createObjectURL(data);

    return textFile;
  };


  var create = document.getElementById('create'),
    textbox = document.getElementById('textbox');

  create.addEventListener('click', function () {
    var link = document.getElementById('downloadlink');
    link.href = makeTextFile(textbox.value);
    link.style.display = 'block';
  }, false);
})();

}//]]> 

</script>


</head>

<body>
  <textarea id="textbox">Type something here</textarea> <button id="create">Create file</button> <a download="info.txt" id="downloadlink" style="display: none">Download</a>


  <script>
  // tell the embed parent frame the height of the content
  if (window.parent && window.parent.parent){
    window.parent.parent.postMessage(["resultsFrame", {
      height: document.body.getBoundingClientRect().height,
      slug: "qm5AG"
    }], "*")
  }
</script>

</body>

</html>

Why does Java have transient fields?

A field which is declare with transient modifier it will not take part in serialized process. When an object is serialized(saved in any state), the values of its transient fields are ignored in the serial representation, while the field other than transient fields will take part in serialization process. That is the main purpose of the transient keyword.

C# Wait until condition is true

Try this

void Function()
{
    while (condition) 
    {
        await Task.Delay(1);
    }
}

This will make the program wait until the condition is not true. You can just invert it by adding a "!" infront of the condition so that it will wait until the condition is true.

What's the best way to limit text length of EditText in Android

TextView tv = new TextView(this);
tv.setFilters(new InputFilter[]{ new InputFilter.LengthFilter(250) });

Go to "next" iteration in JavaScript forEach loop

You can simply return if you want to skip the current iteration.

Since you're in a function, if you return before doing anything else, then you have effectively skipped execution of the code below the return statement.

Paused in debugger in chrome?

Its really a bad experience. if the above answer didn't work for you try this.

Click on the Settings icon and then click on the Restore defaults and reload button.

Press 'F8' until its became normal.

Happy coding!!

Uri content://media/external/file doesn't exist for some devices

Most probably it has to do with caching on the device. Catching the exception and ignoring is not nice but my problem was fixed and it seems to work.

Razor Views not seeing System.Web.Mvc.HtmlHelper

I tried all the solutions here but none of them worked for me. Again, my site runs fine but I don't have intellisense and get red wavy lines under a lot of things in my views that Visual Studio does not recognize, one of them being Html.BeginForm(), as well as anything having to do with ViewBag.

I'm working with a new MVC 5 project. After hours of comparing web.config lines, I finally found what fixed it for me.

My web.config in my root had the following line:

<system.web>
  <compilation debug="true" targetFramework="4.5" />

  <!-- ... -->
</system.web>

I compared to a previous project not using MVC 5, and copied over a block I noticed was missing from the new one, which was the following:

<system.web>
  <compilation debug="true" targetFramework="4.5">
    <assemblies>
      <add assembly="System.Web.Abstractions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
      <add assembly="System.Web.Helpers, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
      <add assembly="System.Web.Routing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
      <add assembly="System.Web.Mvc, Version=5.1.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
      <add assembly="System.Web.WebPages, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
    </assemblies>
  </compilation>

  <!-- ... -->
</system.web>

I copied the above block over to my new project's web.config in the root, changing the versions to match the numbers for each assembly found in my project references (right-clicking each reference mentioned and selecting "Properties", "Version" is given at the bottom of the properties window for the selected reference).

After implementing the above, I now have intellisense and don't get any unknown red lines under things like Html.BeginForm, ViewBag.Title, etc.

jQuery slide left and show

And if you want to vary the speed and include callbacks simply add them like this :

        jQuery.fn.extend({
            slideRightShow: function(speed,callback) {
                return this.each(function() {
                    $(this).show('slide', {direction: 'right'}, speed, callback);
                });
            },
            slideLeftHide: function(speed,callback) {
                return this.each(function() {
                    $(this).hide('slide', {direction: 'left'}, speed, callback);
                });
            },
            slideRightHide: function(speed,callback) {
                return this.each(function() {  
                    $(this).hide('slide', {direction: 'right'}, speed, callback);
                });
            },
            slideLeftShow: function(speed,callback) {
                return this.each(function() {
                    $(this).show('slide', {direction: 'left'}, speed, callback);
                });
            }
        });

Entity Framework Code First - two Foreign Keys from same table

It's also possible to specify the ForeignKey() attribute on the navigation property:

[ForeignKey("HomeTeamID")]
public virtual Team HomeTeam { get; set; }
[ForeignKey("GuestTeamID")]
public virtual Team GuestTeam { get; set; }

That way you don't need to add any code to the OnModelCreate method

Copy existing project with a new name in Android Studio

Perhaps this will help someone.

For Android Studio 4.x Projects, you need following steps:

  • copy project directory to new project directory
  • from Android Studio, open new project directory
  • edit settings.gradle file by updating the rootProject.name='newProjectName'.
  • then sync gradle
  • and here you go the project is ready, and you can start updating manifest, packages, google-services.json and all other stuff

Extract digits from a string in Java

import java.util.*;
public class FindDigits{

 public static void main(String []args){
    FindDigits h=new  FindDigits();
    h.checkStringIsNumerical();
 }

 void checkStringIsNumerical(){
    String h="hello 123 for the rest of the 98475wt355";
     for(int i=0;i<h.length();i++)  {
      if(h.charAt(i)!=' '){
       System.out.println("Is this '"+h.charAt(i)+"' is a digit?:"+Character.isDigit(h.charAt(i)));
       }
    }
 }

void checkStringIsNumerical2(){
    String h="hello 123 for 2the rest of the 98475wt355";
     for(int i=0;i<h.length();i++)  {
         char chr=h.charAt(i);
      if(chr!=' '){
       if(Character.isDigit(chr)){
          System.out.print(chr) ;
       }
       }
    }
 }
}

vertical alignment of text element in SVG

According to SVG spec, alignment-baseline only applies to <tspan>, <textPath>, <tref> and <altGlyph>. My understanding is that it is used to offset those from the <text> object above them. I think what you are looking for is dominant-baseline.

Possible values of dominant-baseline are:

auto | use-script | no-change | reset-size | ideographic | alphabetic | hanging | mathematical | central | middle | text-after-edge | text-before-edge | inherit

Check the W3C recommendation for the dominant-baseline property for more information about each possible value.

What do .c and .h file extensions mean to C?

The .c is the source file and .h is the header file.

Android design support library for API 28 (P) not working

Design support library for androidX is implementation 'com.google.android.material:material:1.0.0'

How to determine the screen width in terms of dp or dip at runtime in Android?

How about using this instead ?

final DisplayMetrics displayMetrics=getResources().getDisplayMetrics();
final float screenWidthInDp=displayMetrics.widthPixels/displayMetrics.density;
final float screenHeightInDp=displayMetrics.heightPixels/displayMetrics.density;

Error - replacement has [x] rows, data has [y]

The answer by @akrun certainly does the trick. For future googlers who want to understand why, here is an explanation...

The new variable needs to be created first.

The variable "valueBin" needs to be already in the df in order for the conditional assignment to work. Essentially, the syntax of the code is correct. Just add one line in front of the code chuck to create this name --

df$newVariableName <- NA

Then you continue with whatever conditional assignment rules you have, like

df$newVariableName[which(df$oldVariableName<=250)] <- "<=250"

I blame whoever wrote that package's error message... The debugging was made especially confusing by that error message. It is irrelevant information that you have two arrays in the df with different lengths. No. Simply create the new column first. For more details, consult this post https://www.r-bloggers.com/translating-weird-r-errors/

How can I test a Windows DLL file to determine if it is 32 bit or 64 bit?

If you have Cygwin installed (which I strongly recommend for a variety of reasons), you could use the 'file' utility on the DLL

file <filename>

which would give an output like this:

icuuc36.dll: MS-DOS executable PE  for MS Windows (DLL) (GUI) Intel 80386 32-bit

How to include js file in another js file?

It is not possible directly. You may as well write some preprocessor which can handle that.

If I understand it correctly then below are the things that can be helpful to achieve that:

  • Use a pre-processor which will run through your JS files for example looking for patterns like "@import somefile.js" and replace them with the content of the actual file. Nicholas Zakas(Yahoo) wrote one such library in Java which you can use (http://www.nczonline.net/blog/2009/09/22/introducing-combiner-a-javascriptcss-concatenation-tool/)

  • If you are using Ruby on Rails then you can give Jammit asset packaging a try, it uses assets.yml configuration file where you can define your packages which can contain multiple files and then refer them in your actual webpage by the package name.

  • Try using a module loader like RequireJS or a script loader like LabJs with the ability to control the loading sequence as well as taking advantage of parallel downloading.

JavaScript currently does not provide a "native" way of including a JavaScript file into another like CSS ( @import ), but all the above mentioned tools/ways can be helpful to achieve the DRY principle you mentioned. I can understand that it may not feel intuitive if you are from a Server-side background but this is the way things are. For front-end developers this problem is typically a "deployment and packaging issue".

Hope it helps.

jQuery UI - Close Dialog When Clicked Outside

It's simple actually you don't need any plugins, just jquery or you can do it with simple javascript.

$('#dialog').on('click', function(e){
  e.stopPropagation();
});
$(document.body).on('click', function(e){
  master.hide();
});

HTML forms - input type submit problem with action=URL when URL contains index.aspx

This appears to be my "preferred" solution:

<form action="www.spufalcons.com/index.aspx?tab=gymnastics&path=gym" method="post">  <div>
<input type="submit" value="Gymnastics"></div>

Sorry for the presentation format - I'm still trying to learn how to use this forum....

I do have a follow-up question. In looking at my MySQL database of URL's it appears that ~30% of the URL's will need to use this post/div wrapper approach. This leaves ~70% that cannot accept the "post" attribute. For example:

<form action="http://www.google.com" method="post">
  <div>
    <input type="submit" value="Google"/>
  </div></form>

does not work. Do you have a recommendation for how to best handle this get/post condition test. Off the top of my head I'm guessing that using PHP to evaluate the existence of the "?" character in the URL may be my best approach, although I'm not sure how to structure the HTML form to accomplish this.

Thank YOU!

How do I detect if a user is already logged in Firebase?

https://firebase.google.com/docs/auth/web/manage-users

You have to add an auth state change observer.

firebase.auth().onAuthStateChanged(function(user) {
  if (user) {
    // User is signed in.
  } else {
    // No user is signed in.
  }
});

Is it possible to use if...else... statement in React render function?

There actually is a way to do exactly what OP is asking. Just render and call an anonymous function like so:

render () {
  return (
    <div>
      {(() => {
        if (someCase) {
          return (
            <div>someCase</div>
          )
        } else if (otherCase) {
          return (
            <div>otherCase</div>
          )
        } else {
          return (
            <div>catch all</div>
          )
        }
      })()}
    </div>
  )
}

String Concatenation using '+' operator

It doesn't - the C# compiler does :)

So this code:

string x = "hello";
string y = "there";
string z = "chaps";
string all = x + y + z;

actually gets compiled as:

string x = "hello";
string y = "there";
string z = "chaps";
string all = string.Concat(x, y, z);

(Gah - intervening edit removed other bits accidentally.)

The benefit of the C# compiler noticing that there are multiple string concatenations here is that you don't end up creating an intermediate string of x + y which then needs to be copied again as part of the concatenation of (x + y) and z. Instead, we get it all done in one go.

EDIT: Note that the compiler can't do anything if you concatenate in a loop. For example, this code:

string x = "";
foreach (string y in strings)
{
    x += y;
}

just ends up as equivalent to:

string x = "";
foreach (string y in strings)
{
    x = string.Concat(x, y);
}

... so this does generate a lot of garbage, and it's why you should use a StringBuilder for such cases. I have an article going into more details about the two which will hopefully answer further questions.

ojdbc14.jar vs. ojdbc6.jar

Also, from ojdbc14 to ojdbc6, several types (e.g., OracleResultSet, OracleStatement) moved from package oracle.jdbc.driver to oracle.jdbc.

How to change the timeout on a .NET WebClient object

According to kisp solution this is my edited version working async:

Class WebConnection.cs

internal class WebConnection : WebClient
{
    internal int Timeout { get; set; }

    protected override WebRequest GetWebRequest(Uri Address)
    {
        WebRequest WebReq = base.GetWebRequest(Address);
        WebReq.Timeout = Timeout * 1000 // Seconds
        return WebReq;
    }
}

The async Task

private async Task GetDataAsyncWithTimeout()
{
    await Task.Run(() =>
    {
        using (WebConnection webClient = new WebConnection())
        {
            webClient.Timeout = 5; // Five seconds
            webClient.DownloadData("https://www.yourwebsite.com");
        }
    });
} // await GetDataAsyncWithTimeout()

Else, if you don't want to use async:

private void GetDataSyncWithTimeout()
{
    using (WebConnection webClient = new WebConnection())
    {
        webClient.Timeout = 5; // Five seconds
        webClient.DownloadData("https://www.yourwebsite.com");
    }
} // GetDataSyncWithTimeout()

How do I seed a random class to avoid getting duplicate random values

public static Random rand = new Random(); // this happens once, and will be great at preventing duplicates

Note, this is not to be used for cryptographic purposes.

Understanding Popen.communicate

.communicate() writes input (there is no input in this case so it just closes subprocess' stdin to indicate to the subprocess that there is no more input), reads all output, and waits for the subprocess to exit.

The exception EOFError is raised in the child process by raw_input() (it expected data but got EOF (no data)).

p.stdout.read() hangs forever because it tries to read all output from the child at the same time as the child waits for input (raw_input()) that causes a deadlock.

To avoid the deadlock you need to read/write asynchronously (e.g., by using threads or select) or to know exactly when and how much to read/write, for example:

from subprocess import PIPE, Popen

p = Popen(["python", "-u", "1st.py"], stdin=PIPE, stdout=PIPE, bufsize=1)
print p.stdout.readline(), # read the first line
for i in range(10): # repeat several times to show that it works
    print >>p.stdin, i # write input
    p.stdin.flush() # not necessary in this case
    print p.stdout.readline(), # read output

print p.communicate("n\n")[0], # signal the child to exit,
                               # read the rest of the output, 
                               # wait for the child to exit

Note: it is a very fragile code if read/write are not in sync; it deadlocks.

Beware of block-buffering issue (here it is solved by using "-u" flag that turns off buffering for stdin, stdout in the child).

bufsize=1 makes the pipes line-buffered on the parent side.

Casting objects in Java

Superclass variable = new subclass object();
This just creates an object of type subclass, but assigns it to the type superclass. All the subclasses' data is created etc, but the variable cannot access the subclasses data/functions. In other words, you cannot call any methods or access data specific to the subclass, you can only access the superclasses stuff.

However, you can cast Superclassvariable to the Subclass and use its methods/data.

How do I format date in jQuery datetimepicker?

For example, I get date/time in format Spanish.

$('#timePicker').datetimepicker({
    defaultDate: new Date(),
    format:'DD/MM/YYYY HH:mm'
});

Android change SDK version in Eclipse? Unable to resolve target android-x

If you're using eclipse you can open default.properties file in your workspace and change the project target to the new sdk (target=android-8 for 2.2). I accidentally selected the 1.5 sdk for my version and didn't catch it until much later, but updating that and restarting eclipse seemed to have done the trick.

How to convert an NSString into an NSNumber

I know this is very late but below code is working for me.

Try this code

NSNumber *number = @([dictionary[@"keyValue"] intValue]]);

This may help you. Thanks

HTML 5 video recording and storing a stream

Currently there is no production ready HTML5 only solution for recording video over the web. The current available solutions are as follows:

HTML Media Capture

Works on mobile devices and uses the OS' video capture app to capture video and upload/POST it to a web server. You will get .mov files on iOS (these are unplayable on Android I've tried) and .mp4 and .3gp on Android. At least the codecs will be the same: H.264 for video and AAC for audio in 99% of the devices.

HTML Media Capture

Image courtesy of https://addpipe.com/blog/the-new-video-recording-prompt-for-media-capture-in-ios9/

Flash and a media server on desktop.

Video recording in Flash works like this: audio and video data is captured from the webcam and microphone, it's encoded using Sorenson Spark or H.264 (video) and Nellymoser Asao or Speex (audio) then it's streamed (rtmp) to a media server (Red5, AMS, Wowza) where it is saved in .flv or .f4v files.

The MediaStream Recording proposal

The MediaStream Recording is a proposal by the the Media Capture Task Force (a joint task force between the WebRTC and Device APIs working groups) for a JS API who's purpose is to make basic video recording in the browser very simple.

Not supported by major browsers. When it'll get implemented (if it will) you will most probably end up with different filetypes (at least .ogg and .webm) and audio/video codecs depending on the browser.

Commercial solutions

There are a few saas and software solutions out there that will handle some or all of the above including addpipe.com, HDFVR, Nimbb and Cameratag.

Further reading:

New warnings in iOS 9: "all bitcode will be dropped"

To fix the issues with the canOpenURL failing. This is because of the new App Transport Security feature in iOS9

Read this post to fix that issue http://discoverpioneer.com/blog/2015/09/18/updating-facebook-integration-for-ios-9/

Allow only numbers and dot in script

Instead of using this:

onkeypress="return fun_AllowOnlyAmountAndDot(this);"

You should use this:

onkeypress="return fun_AllowOnlyAmountAndDot(this.id);"

laravel throwing MethodNotAllowedHttpException

well when i had these problem i faced 2 code errors

{!! Form::model(['method' => 'POST','route' => ['message.store']]) !!}

i corrected it by doing this

{!! Form::open(['method' => 'POST','route' => 'message.store']) !!}

so just to expatiate i changed the form model to open and also the route where wrongly placed in square braces.

Convert generator object to list for debugging

Simply call list on the generator.

lst = list(gen)
lst

Be aware that this affects the generator which will not return any further items.

You also cannot directly call list in IPython, as it conflicts with a command for listing lines of code.

Tested on this file:

def gen():
    yield 1
    yield 2
    yield 3
    yield 4
    yield 5
import ipdb
ipdb.set_trace()

g1 = gen()

text = "aha" + "bebe"

mylst = range(10, 20)

which when run:

$ python code.py 
> /home/javl/sandbox/so/debug/code.py(10)<module>()
      9 
---> 10 g1 = gen()
     11 

ipdb> n
> /home/javl/sandbox/so/debug/code.py(12)<module>()
     11 
---> 12 text = "aha" + "bebe"
     13 

ipdb> lst = list(g1)
ipdb> lst
[1, 2, 3, 4, 5]
ipdb> q
Exiting Debugger.

General method for escaping function/variable/debugger name conflicts

There are debugger commands p and pp that will print and prettyprint any expression following them.

So you could use it as follows:

$ python code.py 
> /home/javl/sandbox/so/debug/code.py(10)<module>()
      9 
---> 10 g1 = gen()
     11 

ipdb> n
> /home/javl/sandbox/so/debug/code.py(12)<module>()
     11 
---> 12 text = "aha" + "bebe"
     13 

ipdb> p list(g1)
[1, 2, 3, 4, 5]
ipdb> c

There is also an exec command, called by prefixing your expression with !, which forces debugger to take your expression as Python one.

ipdb> !list(g1)
[]

For more details see help p, help pp and help exec when in debugger.

ipdb> help exec
(!) statement
Execute the (one-line) statement in the context of
the current stack frame.
The exclamation point can be omitted unless the first word
of the statement resembles a debugger command.
To assign to a global variable you must always prefix the
command with a 'global' command, e.g.:
(Pdb) global list_options; list_options = ['-l']

"make_sock: could not bind to address [::]:443" when restarting apache (installing trac and mod_wsgi)

I am using Ubuntu. I just disabled ssl mode of apache2 and it worked for me.

a2dismod ssl

and then restarted apache2.

service apache2 restart

Parsing json and searching through it

Seems there's a typo (missing colon) in the JSON dict provided by jro.

The correct syntax would be:

jdata = json.load('{"uri": "http:", "foo": "bar"}')

This cleared it up for me when playing with the code.

JavaScript - populate drop down list with array

Here is my answer:

var options = ["1", "2", "3", "4", "5"];
for(m = 0 ; m <= options.length-1; m++){
   var opt= document.createElement("OPTION");
   opt.text = options[m];
   opt.value = (m+1);
   if(options[m] == "5"){
    opt.selected = true;}
document.getElementById("selectNum").options.add(opt);}

Set folder browser dialog start location

To set the directory selected path and the retrieve the new directory:

dlgBrowseForLogDirectory.SelectedPath = m_LogDirectory;
if (dlgBrowseForLogDirectory.ShowDialog() == DialogResult.OK)
{
     txtLogDirectory.Text = dlgBrowseForLogDirectory.SelectedPath;
}

How do you know if Tomcat Server is installed on your PC

In order to make

     http://localhost:8080

work, tomcat has to be started first. You can check server.xml file in conf folder for the port information. You can search if tomcat is installed on your machine. Just go to start and then type tomcat. If it is installed it will give you the directory where it is installed. Then you can select that path and run it from command prompt. Example if tomcat is installed in C:\Programfile\tomcat. You need to set this path in command prompt,go to bin folder and startup. Example: C:\Programfile\tomcat\bin\startup. Else you can also run it by directly going to the path and run startup batch file.

ASP.NET Setting width of DataBound column in GridView

This is going to work for all situations while working with width.

`<asp:TemplateField HeaderText="DATE">
   <ItemTemplate>
   <asp:Label ID="Label1" runat="server" Text='<%# Bind("date") %>' Width="100px"></asp:Label>
   </ItemTemplate>
  </asp:TemplateField>`

Editing an item in a list<T>

  1. You can use the FindIndex() method to find the index of item.
  2. Create a new list item.
  3. Override indexed item with the new item.

List<Class1> list = new List<Class1>();

int index = list.FindIndex(item => item.Number == textBox6.Text);

Class1 newItem = new Class1();
newItem.Prob1 = "SomeValue";

list[index] = newItem;

Spring: how do I inject an HttpServletRequest into a request-scoped bean?

Spring exposes the current HttpServletRequest object (as well as the current HttpSession object) through a wrapper object of type ServletRequestAttributes. This wrapper object is bound to ThreadLocal and is obtained by calling the static method RequestContextHolder.currentRequestAttributes().

ServletRequestAttributes provides the method getRequest() to get the current request, getSession() to get the current session and other methods to get the attributes stored in both the scopes. The following code, though a bit ugly, should get you the current request object anywhere in the application:

HttpServletRequest curRequest = 
((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes())
.getRequest();

Note that the RequestContextHolder.currentRequestAttributes() method returns an interface and needs to be typecasted to ServletRequestAttributes that implements the interface.


Spring Javadoc: RequestContextHolder | ServletRequestAttributes

What to do with commit made in a detached head

Create a branch where you are, then switch to master and merge it:

git branch my-temporary-work
git checkout master
git merge my-temporary-work

Check line for unprintable characters while reading text file

The answer by @T.J.Crowder is Java 6 - in java 7 the valid answer is the one by @McIntosh - though its use of Charset for name for UTF -8 is discouraged:

List<String> lines = Files.readAllLines(Paths.get("/tmp/test.csv"),
    StandardCharsets.UTF_8);
for(String line: lines){ /* DO */ }

Reminds a lot of the Guava way posted by Skeet above - and of course same caveats apply. That is, for big files (Java 7):

BufferedReader reader = Files.newBufferedReader(path, StandardCharsets.UTF_8);
for (String line = reader.readLine(); line != null; line = reader.readLine()) {}

JS Client-Side Exif Orientation: Rotate and Mirror JPEG Images

ok in addition to @user3096626 answer i think it will be more helpful if someone provided code example, the following example will show you how to fix image orientation comes from url (remote images):


Solution 1: using javascript (recommended)

  1. because load-image library doesn't extract exif tags from url images only (file/blob), we will use both exif-js and load-image javascript libraries, so first add these libraries to your page as the follow:

    <script src="https://cdnjs.cloudflare.com/ajax/libs/exif-js/2.1.0/exif.min.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/blueimp-load-image/2.12.2/load-image.min.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/blueimp-load-image/2.12.2/load-image-scale.min.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/blueimp-load-image/2.12.2/load-image-orientation.min.js"></script>
    

    Note the version 2.2 of exif-js seems has issues so we used 2.1

  2. then basically what we will do is

    a - load the image using window.loadImage()

    b - read exif tags using window.EXIF.getData()

    c - convert the image to canvas and fix the image orientation using window.loadImage.scale()

    d - place the canvas into the document

here you go :)

window.loadImage("/your-image.jpg", function (img) {
  if (img.type === "error") {
    console.log("couldn't load image:", img);
  } else {
    window.EXIF.getData(img, function () {
        var orientation = EXIF.getTag(this, "Orientation");
        var canvas = window.loadImage.scale(img, {orientation: orientation || 0, canvas: true});
        document.getElementById("container").appendChild(canvas); 
        // or using jquery $("#container").append(canvas);

    });
  }
});

of course also you can get the image as base64 from the canvas object and place it in the img src attribute, so using jQuery you can do ;)

$("#my-image").attr("src",canvas.toDataURL());

here is the full code on: github: https://github.com/digital-flowers/loadimage-exif-example


Solution 2: using html (browser hack)

there is a very quick and easy hack, most browsers display the image in the right orientation if the image is opened inside a new tab directly without any html (LOL i don't know why), so basically you can display your image using iframe by putting the iframe src attribute as the image url directly:

<iframe src="/my-image.jpg"></iframe>

Solution 3: using css (only firefox & safari on ios)

there is css3 attribute to fix image orientation but the problem it is only working on firefox and safari/ios it is still worth mention because soon it will be available for all browsers (Browser support info from caniuse)

img {
   image-orientation: from-image;
}

Android: adb pull file on desktop

Note need root than:

  • adb root
  • adb pull /data/data/com.google.android.apps.nexuslauncher/databases/launcher.db launcher.db

An example of how to use getopts in bash

#!/bin/bash

usage() { echo "Usage: $0 [-s <45|90>] [-p <string>]" 1>&2; exit 1; }

while getopts ":s:p:" o; do
    case "${o}" in
        s)
            s=${OPTARG}
            ((s == 45 || s == 90)) || usage
            ;;
        p)
            p=${OPTARG}
            ;;
        *)
            usage
            ;;
    esac
done
shift $((OPTIND-1))

if [ -z "${s}" ] || [ -z "${p}" ]; then
    usage
fi

echo "s = ${s}"
echo "p = ${p}"

Example runs:

$ ./myscript.sh
Usage: ./myscript.sh [-s <45|90>] [-p <string>]

$ ./myscript.sh -h
Usage: ./myscript.sh [-s <45|90>] [-p <string>]

$ ./myscript.sh -s "" -p ""
Usage: ./myscript.sh [-s <45|90>] [-p <string>]

$ ./myscript.sh -s 10 -p foo
Usage: ./myscript.sh [-s <45|90>] [-p <string>]

$ ./myscript.sh -s 45 -p foo
s = 45
p = foo

$ ./myscript.sh -s 90 -p bar
s = 90
p = bar

CSS Box Shadow - Top and Bottom Only

As Kristian has pointed out, good control over z-values will often solve your problems.

If that does not work you can take a look at CSS Box Shadow Bottom Only on using overflow hidden to hide excess shadow.

I would also have in mind that the box-shadow property can accept a comma-separated list of shadows like this:

box-shadow: 0px 10px 5px #888, 0px -10px 5px #888;

This will give you some control over the "amount" of shadow in each direction.

Have a look at http://www.css3.info/preview/box-shadow/ for more information about box-shadow.

Hope this was what you were looking for!

How to enable CORS on Firefox?

This Firefox add-on may work for you:

https://addons.mozilla.org/en-US/firefox/addon/cors-everywhere/

It can toggle CORS on and off for development purposes.

MySQL: is a SELECT statement case sensitive?

For anyone who would find himself in a similar situation like me, I add my solution using like:

In my case, I had to select all the rows filtering them by a certain column value. In that column, there were different values, such as 'project_process', 'PROJECT_process', 'PROJECT_PROCESS' and so on.

Notes:

PROJECT/project refers to a certain project name in capital/lowercase letters.

PROCESS/process refers to a certain process name in capital/lowercase letters.

This query was the solution:

SELECT * FROM `table_name` where process like '%project_process' 

(this query allowed me to get all the possible combinations)

Spring - download response as a file

//JAVA PART

@RequestMapping(value = "/report-excel", method = RequestMethod.GET)
    public ResponseEntity<byte[]> getReportExcel(@RequestParam("bookingStatusType") String bookingStatusType,
            @RequestParam("endDate") String endDate, @RequestParam("product") String product, @RequestParam("startDate") String startDate)throws IOException, ParseException {

//Generate Excel from DTO using any logic after that do the following
byte[] body = wb.getBytes();
HttpHeaders header = new HttpHeaders();
        header.setContentType(new MediaType("application", "xlsx"));
        header.set("Content-Disposition", "inline; filename=" + fileName);
        header.setCacheControl("must-revalidate, post-check=0, pre-check=0");
        header.setContentLength(body.length);

 return new ResponseEntity<byte[]>(body, header, HttpStatus.OK);
}



//HTML PART
<html>
<head>
<title>Test</title>
<meta http-equiv="content-type" content="application/x-www-form-urlencoded; charset=UTF-8">
</head>
<body>
  <form name="downloadXLS" method="get" action="http://localhost:8080/rest/report-excel" enctype="multipart/form-data">
    <input type="text" name="bookingStatusType" value="SALES"></input>
    <input type="text" name="endDate" value="abcd"></input>
    <input type="text" name="product" value="FLIGHT"></input>
    <input type="text" name="startDate" value="abcd"></input>
    <input onclick="document.downloadXLS.submit()" value="Submit"></input>
  </form>
</body>
</html>

How to get second-highest salary employees in a table

I think you would want to use DENSE_RANK as you don't know how many employees have the same salary and you did say you wanted nameS of employees.

CREATE TABLE #Test
(
    Id INT,
    Name NVARCHAR(12),
    Salary MONEY
)

SELECT x.Name, x.Salary
FROM
        (
        SELECT  Name, Salary, DENSE_RANK() OVER (ORDER BY Salary DESC) as Rnk
        FROM    #Test
        ) x
WHERE x.Rnk = 2

ROW_NUMBER would give you unique numbering even if the salaries tied, and plain RANK would not give you a '2' as a rank if you had multiple people tying for highest salary. I've corrected this as DENSE_RANK does the best job for this.

Found shared references to a collection org.hibernate.HibernateException

I have experienced a great example of reproducing such a problem. Maybe my experience will help someone one day.

Short version

Check that your @Embedded Id of container has no possible collisions.

Long version

When Hibernate instantiates collection wrapper, it searches for already instantiated collection by CollectionKey in internal Map.

For Entity with @Embedded id, CollectionKey wraps EmbeddedComponentType and uses @Embedded Id properties for equality checks and hashCode calculation.

So if you have two entities with equal @Embedded Ids, Hibernate will instantiate and put new collection by the first key and will find same collection for the second key. So two entities with same @Embedded Id will be populated with same collection.

Example

Suppose you have Account entity which has lazy set of loans. And Account has @Embedded Id consists of several parts(columns).

@Entity
@Table(schema = "SOME", name = "ACCOUNT")
public class Account {
    @OneToMany(fetch = FetchType.LAZY, mappedBy = "account")
    private Set<Loan> loans;

    @Embedded
    private AccountId accountId;

    ...
}

@Embeddable
public class AccountId {
    @Column(name = "X")
    private Long x;
    
    @Column(name = "BRANCH")
    private String branchId;
    
    @Column(name = "Z")
    private String z;

    ...
}

Then suppose that Account has additional property mapped by @Embedded Id but has relation to other entity Branch.

@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "BRANCH")
@MapsId("accountId.branchId")
@NotFound(action = NotFoundAction.IGNORE)//Look at this!
private Branch branch;

It could happen that you have no FK for Account to Brunch relation id DB so Account.BRANCH column can have any value not presented in Branch table.

According to @NotFound(action = NotFoundAction.IGNORE) if value is not present in related table, Hibernate will load null value for the property.

If X and Y columns of two Accounts are same(which is fine), but BRANCH is different and not presented in Branch table, hibernate will load null for both and Embedded Ids will be equal.

So two CollectionKey objects will be equal and will have same hashCode for different Accounts.

result = {CollectionKey@34809} "CollectionKey[Account.loans#Account@43deab74]"
 role = "Account.loans"
 key = {Account@26451} 
 keyType = {EmbeddedComponentType@21355} 
 factory = {SessionFactoryImpl@21356} 
 hashCode = 1187125168
 entityMode = {EntityMode@17415} "pojo"

result = {CollectionKey@35653} "CollectionKey[Account.loans#Account@33470aa]"
 role = "Account.loans"
 key = {Account@35225} 
 keyType = {EmbeddedComponentType@21355} 
 factory = {SessionFactoryImpl@21356} 
 hashCode = 1187125168
 entityMode = {EntityMode@17415} "pojo"

Because of this, Hibernate will load same PesistentSet for two entities.

How to re-create database for Entity Framework?

I would like to add that Lin's answer is correct.

If you improperly delete the MDF you will have to fix it. To fix the screwed up connections in the project to the MDF. Short answer; recreate and delete it properly.

  1. Create a new MDF and name it the same as the old MDF, put it in the same folder location. You can create a new project and create a new mdf. The mdf does not have to match your old tables, because were going to delete it. So create or copy an old one to the correct folder.
  2. Open it in server explorer [double click the mdf from solution explorer]
  3. Delete it in server explorer
  4. Delete it from solution explorer
  5. run update-database -force [Use force if necessary]

Done, enjoy your new db

UPDATE 11/12/14 - I use this all the time when I make a breaking db change. I found this is a great way to roll back your migrations to the original db:

  • Puts the db back to original
  • Run the normal migration to put it back to current

    1. Update-Database -TargetMigration:0 -force [This will destroy all tables and all data.]
    2. Update-Database -force [use force if necessary]

Include of non-modular header inside framework module

I was able to clear dozens of these errors by using Git clean. Here's the command: git clean -dffx && git reset --hard

How can I check if an argument is defined when starting/calling a batch file?

IF "%~1"=="" GOTO :Usage

~ will de-quote %1 if %1 itself is quoted.

" " will protect from special characters passed. for example calling the script with &ping

How to check if a symlink exists

Is the file really a symbolic link? If not, the usual test for existence is -r or -e.

See man test.

Foreign key referring to primary keys across multiple tables?

Assuming that I have understood your scenario correctly, this is what I would call the right way to do this:

Start from a higher-level description of your database! You have employees, and employees can be "ce" employees and "sn" employees (whatever those are). In object-oriented terms, there is a class "employee", with two sub-classes called "ce employee" and "sn employee".

Then you translate this higher-level description to three tables: employees, employees_ce and employees_sn:

  • employees(id, name)
  • employees_ce(id, ce-specific stuff)
  • employees_sn(id, sn-specific stuff)

Since all employees are employees (duh!), every employee will have a row in the employees table. "ce" employees also have a row in the employees_ce table, and "sn" employees also have a row in the employees_sn table. employees_ce.id is a foreign key to employees.id, just as employees_sn.id is.

To refer to an employee of any kind (ce or sn), refer to the employees table. That is, the foreign key you had trouble with should refer to that table!

SVN Commit specific files

You basically put the files you want to commit on the command line

svn ci file1 file2 dir1/file3

How to open local file on Jupyter?

Are you running this on Windows or Linux? If you're on Windows,then you should be use a path like C:\\Users\\apple\\Downloads\train.csv . If you're on Linux, then you can follow the same path.

Failed to load resource: the server responded with a status of 404 (Not Found) error in server

Use your browser's network inspector (F12) to see when the browser is requesting the bgbody.png image and what absolute path it's using and why the server is returning a 404 response.

...assuming that bgbody.png actually exists :)

Is your CSS in a stylesheet file or in a <style> block in a page? If it's in a stylesheet then the relative path must be relative to the CSS stylesheet (not the document that references it). If it's in a page then it must be relative to the current resource path. If you're using non-filesystem-based resource paths (i.e. using URL rewriting or URL routing) then this will cause problems and it's best to always use absolute paths.

Going by your relative path it looks like you store your images separately from your stylesheets. I don't think this is a good idea - I support storing images and other resources, like fonts, in the same directory as the stylesheet itself, as it simplifies paths and is also a more logical filesystem arrangement.

Detect Safari browser

I don't know why the OP wanted to detect Safari, but in the rare case you need browser sniffing nowadays it's problably more important to detect the render engine than the name of the browser. For example on iOS all browsers use the Safari/Webkit engine, so it's pointless to get "chrome" or "firefox" as browser name if the underlying renderer is in fact Safari/Webkit. I haven't tested this code with old browsers but it works with everything fairly recent on Android, iOS, OS X, Windows and Linux.

<script>
    let browserName = "";

    if(navigator.vendor.match(/google/i)) {
        browserName = 'chrome/blink';
    }
    else if(navigator.vendor.match(/apple/i)) {
        browserName = 'safari/webkit';
    }
    else if(navigator.userAgent.match(/firefox\//i)) {
        browserName = 'firefox/gecko';
    }
    else if(navigator.userAgent.match(/edge\//i)) {
        browserName = 'edge/edgehtml';
    }
    else if(navigator.userAgent.match(/trident\//i)) {
        browserName = 'ie/trident';
    }
    else
    {
        browserName = navigator.userAgent + "\n" + navigator.vendor;
    }
    alert(browserName);
</script>

To clarify:

  • All browsers under iOS will be reported as "safari/webkit"
  • All browsers under Android but Firefox will be reported as "chrome/blink"
  • Chrome, Opera, Blisk, Vivaldi etc. will all be reported as "chrome/blink" under Windows, OS X or Linux

Send POST parameters with MultipartFormData using Alamofire, in iOS Swift

func funcationname()
{

    var parameters = [String:String]()
    let apiToken = "Bearer \(UserDefaults.standard.string(forKey: "vAuthToken")!)"
    let headers = ["Vauthtoken":apiToken]
    let mobile = "\(ApiUtillity.sharedInstance.getUserData(key: "mobile"))"
    parameters = ["first_name":First_name,"last_name":last_name,"email":Email,"mobile_no":mobile]

    print(parameters)
    ApiUtillity.sharedInstance.showSVProgressHUD(text: "Loading...")
    let URL1 = ApiUtillity.sharedInstance.API(Join: "user/update_profile")
    let url = URL(string: URL1.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!)
    var urlRequest = URLRequest(url: url!)
    urlRequest.httpMethod = "POST"
    urlRequest.allHTTPHeaderFields = headers
    Alamofire.upload(multipartFormData: { (multipartFormData) in

        multipartFormData.append(self.imageData_pf_pic, withName: "profile_image", fileName: "image.jpg", mimeType: "image/jpg")


        for (key, value) in parameters {

            multipartFormData.append((value as AnyObject).data(using: String.Encoding.utf8.rawValue)!, withName: key)
        }

    }, with: urlRequest) { (encodingResult) in

        switch encodingResult {
        case .success(let upload, _, _):
            upload.responseJSON { response in
                if let JSON = response.result.value {
                    print("JSON: \(JSON)")
                    let status = (JSON as AnyObject).value(forKey: "status") as! Int
                    let sts = Int(status)
                    if sts == 200
                    {
                        ApiUtillity.sharedInstance.dismissSVProgressHUD()
                        let UserData = ((JSON as AnyObject).value(forKey: "data") as! NSDictionary)
                        ApiUtillity.sharedInstance.setUserData(data: UserData)


                    }
                    else
                    {
                        ApiUtillity.sharedInstance.dismissSVProgressHUD()

                        let ErrorDic:NSDictionary = (JSON as AnyObject).value(forKey: "message") as! NSDictionary

                        let Errormobile_no = ErrorDic.value(forKey: "mobile_no") as? String
                        let Erroremail = ErrorDic.value(forKey: "email") as? String

                        if Errormobile_no?.count == nil
                        {}
                        else
                        {
                            ApiUtillity.sharedInstance.dismissSVProgressHUDWithError(error: Errormobile_no!)
                        }
                        if Erroremail?.count == nil
                        {}
                        else
                        {
                            ApiUtillity.sharedInstance.dismissSVProgressHUDWithError(error: Erroremail!)
                        }
                    }

                }

            }

        case .failure(let encodingError):
            ApiUtillity.sharedInstance.dismissSVProgressHUD()
            print(encodingError)
        }

    }
}

How to get a pixel's x,y coordinate color from an image?

With : i << 2

const data = context.getImageData(x, y, width, height).data;
const pixels = [];

for (let i = 0, dx = 0; dx < data.length; i++, dx = i << 2) {
    if (data[dx+3] <= 8)
        console.log("transparent x= " + i);
}

How to get the month name in C#?

You can use the CultureInfo to get the month name. You can even get the short month name as well as other fun things.

I would suggestion you put these into extension methods, which will allow you to write less code later. However you can implement however you like.

Here is an example of how to do it using extension methods:

using System;
using System.Globalization;

class Program
{
    static void Main()
    {

        Console.WriteLine(DateTime.Now.ToMonthName());
        Console.WriteLine(DateTime.Now.ToShortMonthName());
        Console.Read();
    }
}

static class DateTimeExtensions
{
    public static string ToMonthName(this DateTime dateTime)
    {
        return CultureInfo.CurrentCulture.DateTimeFormat.GetMonthName(dateTime.Month);
    }

    public static string ToShortMonthName(this DateTime dateTime)
    {
        return CultureInfo.CurrentCulture.DateTimeFormat.GetAbbreviatedMonthName(dateTime.Month);
    }
}

Hope this helps!

Set custom attribute using JavaScript

Use the setAttribute method:

document.getElementById('item1').setAttribute('data', "icon: 'base2.gif', url: 'output.htm', target: 'AccessPage', output: '1'");

But you really should be using data followed with a dash and with its property, like:

<li ... data-icon="base.gif" ...>

And to do it in JS use the dataset property:

document.getElementById('item1').dataset.icon = "base.gif";

How do I generate a SALT in Java for Salted-Hash?

You were right regarding how you want to generate salt i.e. its nothing but a random number. For this particular case it would protect your system from possible Dictionary attacks. Now, for the second problem what you could do is instead of using UTF-8 encoding you may want to use Base64. Here, is a sample for generating a hash. I am using Apache Common Codecs for doing the base64 encoding you may select one of your own

public byte[] generateSalt() {
        SecureRandom random = new SecureRandom();
        byte bytes[] = new byte[20];
        random.nextBytes(bytes);
        return bytes;
    }

public String bytetoString(byte[] input) {
        return org.apache.commons.codec.binary.Base64.encodeBase64String(input);
    }

public byte[] getHashWithSalt(String input, HashingTechqniue technique, byte[] salt) throws NoSuchAlgorithmException {
        MessageDigest digest = MessageDigest.getInstance(technique.value);
        digest.reset();
        digest.update(salt);
        byte[] hashedBytes = digest.digest(stringToByte(input));
        return hashedBytes;
    }
public byte[] stringToByte(String input) {
        if (Base64.isBase64(input)) {
            return Base64.decodeBase64(input);

        } else {
            return Base64.encodeBase64(input.getBytes());
        }
    }

Here is some additional reference of the standard practice in password hashing directly from OWASP

How can I remove a specific item from an array?

splice() function is able to give you back item in array as well as remove item/ items from specific index

_x000D_
_x000D_
function removeArrayItem(index, array) {
 array.splice(index, 1);
 return array;
}

let array = [1,2,3,4];
let index = 2;
array = removeArrayItem(index, array);
console.log(array);
_x000D_
_x000D_
_x000D_

Get the distance between two geo points

Location loc1 = new Location("");
loc1.setLatitude(lat1);
loc1.setLongitude(lon1);

Location loc2 = new Location("");
loc2.setLatitude(lat2);
loc2.setLongitude(lon2);

float distanceInMeters = loc1.distanceTo(loc2);

Reference: http://developer.android.com/reference/android/location/Location.html#distanceTo(android.location.Location)

Python, HTTPS GET with basic authentication

using only standard modules and no manual header encoding

...which seems to be the intended and most portable way

the concept of python urllib is to group the numerous attributes of the request into various managers/directors/contexts... which then process their parts:

import urllib.request, ssl

# to avoid verifying ssl certificates
httpsHa = urllib.request.HTTPSHandler(context= ssl._create_unverified_context())

# setting up realm+urls+user-password auth
# (top_level_url may be sequence, also the complete url, realm None is default)
top_level_url = 'https://ip:port_or_domain'
# of the std managers, this can send user+passwd in one go,
# not after HTTP req->401 sequence
password_mgr = urllib.request.HTTPPasswordMgrWithPriorAuth()
password_mgr.add_password(None, top_level_url, "user", "password", is_authenticated=True)

handler = urllib.request.HTTPBasicAuthHandler(password_mgr)
# create OpenerDirector
opener = urllib.request.build_opener(handler, httpsHa)

url = top_level_url + '/some_url?some_query...'
response = opener.open(url)

print(response.read())

What is the purpose of a self executing function in javascript?

Namespacing. JavaScript's scopes are function-level.

How can I set the font-family & font-size inside of a div?

You need a semicolon after font-family: Arial, Helvetica, sans-serif. This will make your updated code the following:

<!DOCTYPE>
<html>
    <head>
        <title>DIV Font</title>

        <style>
            .my_text
            {
                font-family:    Arial, Helvetica, sans-serif;
                font-size:      40px;
                font-weight:    bold;
            }
        </style>
    </head>

    <body>
        <div class="my_text">some text</div>
    </body>
</html>

Java difference between FileWriter and BufferedWriter

http://docs.oracle.com/javase/1.5.0/docs/api/java/io/BufferedWriter.html

In general, a Writer sends its output immediately to the underlying character or byte stream. Unless prompt output is required, it is advisable to wrap a BufferedWriter around any Writer whose write() operations may be costly, such as FileWriters and OutputStreamWriters. For example,

PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("foo.out")));

will buffer the PrintWriter's output to the file. Without buffering, each invocation of a print() method would cause characters to be converted into bytes that would then be written immediately to the file, which can be very inefficient.

Saving numpy array to txt file row wise

I know this is old, but none of these answers solved the root problem of numpy not saving the array row-wise. I found that this one liner did the trick for me:

b = np.matrix(a)
np.savetxt("file", b)

CSS3 transition on click using pure CSS

As jeremyjjbrow said, :active pseudo won't persist. But there's a hack for doing it on pure css. You can wrap it on a <a> tag, and apply the :active on it, like this:

<a class="test">
    <img class="crossRotate" src="images/cross.png" alt="Cross Menu button" />
 </a>

And the css:

.test:active .crossRotate {
    transform: rotate(45deg);
    -webkit-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
    }

Try it out... It works (at least on Chrome)!

When use getOne and findOne methods Spring Data JPA

1. Why does the getOne(id) method fail?

See this section in the docs. You overriding the already in place transaction might be causing the issue. However, without more info this one is difficult to answer.

2. When I should use the getOne(id) method?

Without digging into the internals of Spring Data JPA, the difference seems to be in the mechanism used to retrieve the entity.

If you look at the JavaDoc for getOne(ID) under See Also:

See Also:
EntityManager.getReference(Class, Object)

it seems that this method just delegates to the JPA entity manager's implementation.

However, the docs for findOne(ID) do not mention this.

The clue is also in the names of the repositories. JpaRepository is JPA specific and therefore can delegate calls to the entity manager if so needed. CrudRepository is agnostic of the persistence technology used. Look here. It's used as a marker interface for multiple persistence technologies like JPA, Neo4J etc.

So there's not really a 'difference' in the two methods for your use cases, it's just that findOne(ID) is more generic than the more specialised getOne(ID). Which one you use is up to you and your project but I would personally stick to the findOne(ID) as it makes your code less implementation specific and opens the doors to move to things like MongoDB etc. in the future without too much refactoring :)

Countdown timer in React

The problem is in your "this" value. Timer function cannot access the "state" prop because run in a different context. I suggest you to do something like this:

...
startTimer = () => {
  let interval = setInterval(this.timer.bind(this), 1000);
  this.setState({ interval });
};

As you can see I've added a "bind" method to your timer function. This allows the timer, when called, to access the same "this" of your react component (This is the primary problem/improvement when working with javascript in general).

Another option is to use another arrow function:

startTimer = () => {
  let interval = setInterval(() => this.timer(), 1000);
  this.setState({ interval });
};

Difference between r+ and w+ in fopen()

w+

#include <stdio.h>
int main()
{
   FILE *fp;
   fp = fopen("test.txt", "w+");  //write and read mode
   fprintf(fp, "This is testing for fprintf...\n"); 

   rewind(fp); //rewind () function moves file pointer position to the beginning of the file.
   char ch;
   while((ch=getc(fp))!=EOF)
   putchar(ch);

   fclose(fp);
}  

output

This is testing for fprintf...

test.txt

This is testing for fprintf...

w and r to form w+

#include <stdio.h>
int main()
{
   FILE *fp;

   fp = fopen("test.txt", "w"); //only write mode
   fprintf(fp, "This is testing for fprintf...\n"); 
   fclose(fp);
   fp = fopen("test.txt", "r");
   char ch;
   while((ch=getc(fp))!=EOF)
   putchar(ch);
   fclose(fp);
}  

output

This is testing for fprintf...

test.txt

This is testing for fprintf...

r+

test.txt

This is testing for fprintf...
#include<stdio.h>
int main()
{
    FILE *fp;
    fp = fopen("test.txt", "r+");  //read and write mode
    char ch;
    while((ch=getc(fp))!=EOF)
    putchar(ch);
    rewind(fp); //rewind () function moves file pointer position to the beginning of the file.
    fprintf(fp, "This is testing for fprintf again...\n");
    fclose(fp);
    return 0;
}

output

This is testing for fprintf...

test.txt

This is testing for fprintf again...

r and w to form r+

test.txt

This is testing for fprintf...
#include<stdio.h>
int main()
{
    FILE *fp;
    fp = fopen("test.txt", "r"); 
    char ch;
    while((ch=getc(fp))!=EOF)
    putchar(ch);
    fclose(fp);

    fp=fopen("test.txt","w");
    fprintf(fp, "This is testing for fprintf again...\n");
    fclose(fp);
    return 0;
}

output

This is testing for fprintf...

test.txt

This is testing for fprintf again...

a+

test.txt

This is testing for fprintf...
#include<stdio.h>
int main()
{
    FILE *fp;
    fp = fopen("test.txt", "a+");  //append and read mode
    char ch;
    while((ch=getc(fp))!=EOF)
    putchar(ch);
    rewind(fp); //rewind () function moves file pointer position to the beginning of the file.
    fprintf(fp, "This is testing for fprintf again...\n");
    fclose(fp);
    return 0;
}

output

This is testing for fprintf...

test.txt

This is testing for fprintf...
This is testing for fprintf again...

a and r to form a+

test.txt

This is testing for fprintf...
#include<stdio.h>
int main()
{
    FILE *fp;
    fp = fopen("test.txt", "a");  //append and read mode
    char ch;
    while((ch=getc(fp))!=EOF)
    putchar(ch);
    fclose(fp);
    fp=fopen("test.txt","r");
    fprintf(fp, "This is testing for fprintf again...\n");
    fclose(fp);
    return 0;
}

output

This is testing for fprintf...

test.txt

This is testing for fprintf...
This is testing for fprintf again...

How to keep the local file or the remote file during merge using Git and the command line?

This approach seems more straightforward, avoiding the need to individually select each file:

# keep remote files
git merge --strategy-option theirs
# keep local files
git merge --strategy-option ours

or

# keep remote files
git pull -Xtheirs
# keep local files
git pull -Xours

Copied directly from: Resolve Git merge conflicts in favor of their changes during a pull

Text overwrite in visual studio 2010

I'm using Visual Studio with Parallels/Win 7 on a MacBook laptop keyboard and the only thing that worked was Fn + Enter/Return (that's the Mac shortcut for Insert).

How to change the background color on a Java panel?

You could call:


getContentPane().setBackground(Color.black);

Or add a JPanel to the JFrame your using. Then add your components to the JPanel. This will allow you to call


setBackground(Color.black);

on the JPanel to set the background color.

How to create byte array from HttpPostedFile

For images if your using Web Pages v2 use the WebImage Class

var webImage = new System.Web.Helpers.WebImage(Request.Files[0].InputStream);
byte[] imgByteArray = webImage.GetBytes();

String strip() for JavaScript?

Steven Levithan once wrote about how to implement a Faster JavaScript Trim. It’s definitely worth a look.

Java integer list

To insert a sleep command you can use Thread.sleep(2000). So the code would be:

List<Integer> myCoords = new ArrayList<Integer>();
myCoords.add(10);
myCoords.add(20);
myCoords.add(30);
myCoords.add(40);
myCoords.add(50);
Iterator<Integer> myListIterator = someList.iterator(); 
while (myListIterator.hasNext()) {
    Integer coord = myListIterator.next();    
    System.out.println(coord);
    Thread.Sleep(2000);
}

This would output: 10 20 30 40 50

If you want the numbers after each other you could use: System.out.print(coord +" " ); and if you want to repeat the section you can put it in another while loop.

List<Integer> myCoords = new ArrayList<Integer>();
myCoords.add(10);
myCoords.add(20);
myCoords.add(30);
myCoords.add(40);
myCoords.add(50);
while(true)
    Iterator<Integer> myListIterator = someList.iterator(); 
    while (myListIterator.hasNext()) {
        Integer coord = myListIterator.next();    
        System.out.print(coord + " ");
        Thread.Sleep(2000);
    }
}

This would output: 10 20 30 40 50 10 20 30 40 50 ... and never stop until you kill the program.

Edit: You do have to put the sleep command in a try catch block

ArrayList initialization equivalent to array initialization

Here is the closest you can get:

ArrayList<String> list = new ArrayList(Arrays.asList("Ryan", "Julie", "Bob"));

You can go even simpler with:

List<String> list = Arrays.asList("Ryan", "Julie", "Bob")

Looking at the source for Arrays.asList, it constructs an ArrayList, but by default is cast to List. So you could do this (but not reliably for new JDKs):

ArrayList<String> list = (ArrayList<String>)Arrays.asList("Ryan", "Julie", "Bob")

AngularJS- Login and Authentication in each route and controller

For instance an application has two user called ap and auc. I am passing an extra property to each route and handling the routing based on the data i get in $routeChangeStart.

Try this:

angular.module("app").config(['$routeProvider',
function ($routeProvider) {

    $routeProvider.
            when('/ap', {
                templateUrl: 'template1.html',
                controller: 'template1',
                isAp: 'ap',
            }).
            when('/auc', {
                templateUrl: 'template2.html',
                controller: 'template2',
                isAp: 'common',
            }).
            when('/ic', {
                templateUrl: 'template3.html',
                controller: 'template3',
                isAp: 'auc',
            }).
            when('/mup', {
                templateUrl: 'template4.html',
                controller: 'template4',
                isAp: 'ap',
            }).

            when('/mnu', {
                templateUrl: 'template5.html',
                controller: 'template5',
                isAp: 'common',
            }).                               
            otherwise({
                redirectTo: '/ap',
            });
   }]);

app.js:

.run(['$rootScope', '$location', function ($rootScope, $location) {                
    $rootScope.$on("$routeChangeStart", function (event, next, current) {
        if (next.$$route.isAp != 'common') {
            if ($rootScope.userTypeGlobal == 1) {
                if (next.$$route.isAp != 'ap') {
                    $location.path("/ap");
                }
            }
            else {
                if (next.$$route.isAp != 'auc') {
                    $location.path("/auc");
                }                        
            }
        }

    });
}]);

Using Sockets to send and receive data

    //Client

    import java.io.*;
    import java.net.*;

    public class Client {
        public static void main(String[] args) {

        String hostname = "localhost";
        int port = 6789;

        // declaration section:
        // clientSocket: our client socket
        // os: output stream
        // is: input stream

            Socket clientSocket = null;  
            DataOutputStream os = null;
            BufferedReader is = null;

        // Initialization section:
        // Try to open a socket on the given port
        // Try to open input and output streams

            try {
                clientSocket = new Socket(hostname, port);
                os = new DataOutputStream(clientSocket.getOutputStream());
                is = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
            } catch (UnknownHostException e) {
                System.err.println("Don't know about host: " + hostname);
            } catch (IOException e) {
                System.err.println("Couldn't get I/O for the connection to: " + hostname);
            }

        // If everything has been initialized then we want to write some data
        // to the socket we have opened a connection to on the given port

        if (clientSocket == null || os == null || is == null) {
            System.err.println( "Something is wrong. One variable is null." );
            return;
        }

        try {
            while ( true ) {
            System.out.print( "Enter an integer (0 to stop connection, -1 to stop server): " );
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            String keyboardInput = br.readLine();
            os.writeBytes( keyboardInput + "\n" );

            int n = Integer.parseInt( keyboardInput );
            if ( n == 0 || n == -1 ) {
                break;
            }

            String responseLine = is.readLine();
            System.out.println("Server returns its square as: " + responseLine);
            }

            // clean up:
            // close the output stream
            // close the input stream
            // close the socket

            os.close();
            is.close();
            clientSocket.close();   
        } catch (UnknownHostException e) {
            System.err.println("Trying to connect to unknown host: " + e);
        } catch (IOException e) {
            System.err.println("IOException:  " + e);
        }
        }           
    }





//Server




import java.io.*;
import java.net.*;

public class Server1 {
    public static void main(String args[]) {
    int port = 6789;
    Server1 server = new Server1( port );
    server.startServer();
    }

    // declare a server socket and a client socket for the server

    ServerSocket echoServer = null;
    Socket clientSocket = null;
    int port;

    public Server1( int port ) {
    this.port = port;
    }

    public void stopServer() {
    System.out.println( "Server cleaning up." );
    System.exit(0);
    }

    public void startServer() {
    // Try to open a server socket on the given port
    // Note that we can't choose a port less than 1024 if we are not
    // privileged users (root)

        try {
        echoServer = new ServerSocket(port);
        }
        catch (IOException e) {
        System.out.println(e);
        }   

    System.out.println( "Waiting for connections. Only one connection is allowed." );

    // Create a socket object from the ServerSocket to listen and accept connections.
    // Use Server1Connection to process the connection.

    while ( true ) {
        try {
        clientSocket = echoServer.accept();
        Server1Connection oneconnection = new Server1Connection(clientSocket, this);
        oneconnection.run();
        }   
        catch (IOException e) {
        System.out.println(e);
        }
    }
    }
}

class Server1Connection {
    BufferedReader is;
    PrintStream os;
    Socket clientSocket;
    Server1 server;

    public Server1Connection(Socket clientSocket, Server1 server) {
    this.clientSocket = clientSocket;
    this.server = server;
    System.out.println( "Connection established with: " + clientSocket );
    try {
        is = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        os = new PrintStream(clientSocket.getOutputStream());
    } catch (IOException e) {
        System.out.println(e);
    }
    }

    public void run() {
        String line;
    try {
        boolean serverStop = false;

            while (true) {
                line = is.readLine();
        System.out.println( "Received " + line );
                int n = Integer.parseInt(line);
        if ( n == -1 ) {
            serverStop = true;
            break;
        }
        if ( n == 0 ) break;
                os.println("" + n*n ); 
            }

        System.out.println( "Connection closed." );
            is.close();
            os.close();
            clientSocket.close();

        if ( serverStop ) server.stopServer();
    } catch (IOException e) {
        System.out.println(e);
    }
    }
}

Laravel Eloquent LEFT JOIN WHERE NULL

use Illuminate\Database\Eloquent\Builder;

$query = Customers::with('orders');
$query = $query->whereHas('orders', function (Builder $query) use ($request) {
     $query = $query->where('orders.customer_id', 'NULL') 
});
    $query = $query->get();

How can I delete derived data in Xcode 8?

In Xcode 8, all the derived data is automatically cleaned. If you want to do it by hand, go to Locations tab from the Preferences, locate project's derived data folder, and delete files related to the project.

In macOS 10.12 and later, Xcode cleans up stale derived data, precompiled headers, and module caches. (23282174)

Xcode 8.0 Release Notes

Credits to @charmingToad

But from what I observed, the same behaviour is typical when using Xcode 8 on OS X 10.11.5/6

Delete branches in Bitbucket

Step 1 : Login in Bitbucket

Step 2 : Select Your Repository in Repositories list. enter image description here

Step 3 : Select branches in left hand side menu. enter image description here

Step4 : Cursor point on branch click on three dots (...) Select Delete (See in Bellow Image) enter image description here

What is the `data-target` attribute in Bootstrap 3?

The toggle tells Bootstrap what to do and the target tells Bootstrap which element is going to open. So whenever a link like that is clicked, a modal with an id of “basicModal” will appear.

System.currentTimeMillis vs System.nanoTime

For game graphics & smooth position updates, use System.nanoTime() rather than System.currentTimeMillis(). I switched from currentTimeMillis() to nanoTime() in a game and got a major visual improvement in smoothness of motion.

While one millisecond may seem as though it should already be precise, visually it is not. The factors nanoTime() can improve include:

  • accurate pixel positioning below wall-clock resolution
  • ability to anti-alias between pixels, if you want
  • Windows wall-clock inaccuracy
  • clock jitter (inconsistency of when wall-clock actually ticks forward)

As other answers suggest, nanoTime does have a performance cost if called repeatedly -- it would be best to call it just once per frame, and use the same value to calculate the entire frame.

Change button text from Xcode?

Swift 5 Use button.setTitle()

  1. If using storyboards, make a IBOutlet reference.

@IBOutlet weak var button: UIButton!

  1. Call setTitle on the button followed by the text and the state.

button.setTitle("Button text here", forState: .normal)

Is it possible to pull just one file in Git?

Here is a slightly easier method I just came up with when researching this:

git fetch {remote}
git checkout FETCH_HEAD -- {file}

Why do I get an UnsupportedOperationException when trying to remove an element from a List?

This one has burned me many times. Arrays.asList creates an unmodifiable list. From the Javadoc: Returns a fixed-size list backed by the specified array.

Create a new list with the same content:

newList.addAll(Arrays.asList(newArray));

This will create a little extra garbage, but you will be able to mutate it.

How to install python developer package?

yum install python-devel will work.

If yum doesn't work then use

apt-get install python-dev

How to delete duplicate lines in a file without sorting it in Unix?

The one-liner that Andre Miller posted above works except for recent versions of sed when the input file ends with a blank line and no chars. On my Mac my CPU just spins.

Infinite loop if last line is blank and has no chars:

sed '$!N; /^\(.*\)\n\1$/!P; D'

Doesn't hang, but you lose the last line

sed '$d;N; /^\(.*\)\n\1$/!P; D'

The explanation is at the very end of the sed FAQ:

The GNU sed maintainer felt that despite the portability problems
this would cause, changing the N command to print (rather than
delete) the pattern space was more consistent with one's intuitions
about how a command to "append the Next line" ought to behave.
Another fact favoring the change was that "{N;command;}" will
delete the last line if the file has an odd number of lines, but
print the last line if the file has an even number of lines.

To convert scripts which used the former behavior of N (deleting
the pattern space upon reaching the EOF) to scripts compatible with
all versions of sed, change a lone "N;" to "$d;N;".

Is there a way to make mv create the directory to be moved to if it doesn't exist?

You can chain commands:mkdir ~/bar/baz | mv foo.c ~/bar/baz/
or shell script is here:

#!/bin/bash
mkdir $2 | mv $1 $2

1. Open any text editor
2. Copy-paste shell script.
3. Save it as mkdir_mv.sh
4. Enter your script's directory: cd your/script/directory
5. Change file mode : chmod +x mkdir_mv.sh
6. Set alias: alias mv="./mkdir_mv.sh"
Now, whenever you run command mv moving directory will be created if does not exists.

How to remove newlines from beginning and end of a string?

If your string is potentially null, consider using StringUtils.trim() - the null-safe version of String.trim().

Hibernate throws MultipleBagFetchException - cannot simultaneously fetch multiple bags

Add a Hibernate-specific @Fetch annotation to your code:

@OneToMany(mappedBy="parent", fetch=FetchType.EAGER)
@Fetch(value = FetchMode.SUBSELECT)
private List<Child> childs;

This should fix the issue, related to Hibernate bug HHH-1718

How do I force a DIV block to extend to the bottom of a page even if it has no content?

you can kinda hack it with the min-height declaration

<div style="min-height: 100%">stuff</div>

Rails params explained?

Params contains the following three groups of parameters:

  1. User supplied parameters
    • GET (http://domain.com/url?param1=value1&param2=value2 will set params[:param1] and params[:param2])
    • POST (e.g. JSON, XML will automatically be parsed and stored in params)
    • Note: By default, Rails duplicates the user supplied parameters and stores them in params[:user] if in UsersController, can be changed with wrap_parameters setting
  2. Routing parameters
    • match '/user/:id' in routes.rb will set params[:id]
  3. Default parameters
    • params[:controller] and params[:action] is always available and contains the current controller and action

How To Execute SSH Commands Via PHP

Do you have the SSH2 extension available?

Docs: http://www.php.net/manual/en/function.ssh2-exec.php

$connection = ssh2_connect('shell.example.com', 22);
ssh2_auth_password($connection, 'username', 'password');

$stream = ssh2_exec($connection, '/usr/local/bin/php -i');

Why not inherit from List<T>?

When is it acceptable?

To quote Eric Lippert:

When you're building a mechanism that extends the List<T> mechanism.

For example, you are tired of the absence of the AddRange method in IList<T>:

public interface IMoreConvenientListInterface<T> : IList<T>
{
    void AddRange(IEnumerable<T> collection);
}

public class MoreConvenientList<T> : List<T>, IMoreConvenientListInterface<T> { }

Spring Boot access static resources missing scr/main/resources

You can use following code to read file in String from resource folder.

final Resource resource = new ClassPathResource("public.key");
String publicKey = null;
try {
     publicKey = new String(Files.readAllBytes(resource.getFile().toPath()), StandardCharsets.UTF_8);
} catch (IOException e) {
     e.printStackTrace();
}

How to open select file dialog via js?

For the sake of completeness, Ron van der Heijden's solution in pure JavaScript:

<button onclick="document.querySelector('.inputFile').click();">Select File ...</button>
<input class="inputFile" type="file" style="display: none;">

Mongoose delete array element in document and save

The checked answer does work but officially in MongooseJS latest, you should use pull.

doc.subdocs.push({ _id: 4815162342 }) // added
doc.subdocs.pull({ _id: 4815162342 }) // removed

https://mongoosejs.com/docs/api.html#mongoosearray_MongooseArray-pull

I was just looking that up too.

See Daniel's answer for the correct answer. Much better.

Best way to create an empty map in Java

1) If the Map can be immutable:

Collections.emptyMap()

// or, in some cases:
Collections.<String, String>emptyMap()

You'll have to use the latter sometimes when the compiler cannot automatically figure out what kind of Map is needed (this is called type inference). For example, consider a method declared like this:

public void foobar(Map<String, String> map){ ... }

When passing the empty Map directly to it, you have to be explicit about the type:

foobar(Collections.emptyMap());                 // doesn't compile
foobar(Collections.<String, String>emptyMap()); // works fine

2) If you need to be able to modify the Map, then for example:

new HashMap<String, String>()

(as tehblanx pointed out)


Addendum: If your project uses Guava, you have the following alternatives:

1) Immutable map:

ImmutableMap.of()
// or:
ImmutableMap.<String, String>of()

Granted, no big benefits here compared to Collections.emptyMap(). From the Javadoc:

This map behaves and performs comparably to Collections.emptyMap(), and is preferable mainly for consistency and maintainability of your code.

2) Map that you can modify:

Maps.newHashMap()
// or:
Maps.<String, String>newHashMap()

Maps contains similar factory methods for instantiating other types of maps as well, such as TreeMap or LinkedHashMap.


Update (2018): On Java 9 or newer, the shortest code for creating an immutable empty map is:

Map.of()

...using the new convenience factory methods from JEP 269.

How do you refresh the MySQL configuration file without restarting?

Reloading the configuration file (my.cnf) cannot be done without restarting the mysqld server.

FLUSH LOGS only rotates a few log files.

SET @@...=... sets it for anyone not yet logged in, but it will go away after the next restart. But that gives a clue... Do the SET, and change my.cnf; that way you are covered. Caveat: Not all settings can be performed via SET.

New with MySQL 8.0...

SET PERSIST ... will set the global setting and save it past restarts. Nearly all settings can be adjusted this way.

Making the main scrollbar always visible

Setting height to 101% is my solution to the problem. You pages will no longer 'flick' when switching between ones that exceed the viewport height and ones that do not.

What does 'low in coupling and high in cohesion' mean

Long story short, low coupling as I understood it meant components can be swapped out without affecting the proper functioning of a system. Basicaly modulize your system into functioning components that can be updated individually without breaking the system

How to implement the ReLU function in Numpy

Richard Möhn's comparison is not fair.
As Andrea Di Biagio's comment, the in-place method np.maximum(x, 0, x) will modify x at the first loop.

So here is my benchmark:

import numpy as np

def baseline():
    x = np.random.random((5000, 5000)) - 0.5
    return x

def relu_mul():
    x = np.random.random((5000, 5000)) - 0.5
    out = x * (x > 0)
    return out

def relu_max():
    x = np.random.random((5000, 5000)) - 0.5
    out = np.maximum(x, 0)
    return out

def relu_max_inplace():
    x = np.random.random((5000, 5000)) - 0.5
    np.maximum(x, 0, x)
    return x 

Timing it:

print("baseline:")
%timeit -n10 baseline()
print("multiplication method:")
%timeit -n10 relu_mul()
print("max method:")
%timeit -n10 relu_max()
print("max inplace method:")
%timeit -n10 relu_max_inplace()

Get the results:

baseline:
10 loops, best of 3: 425 ms per loop
multiplication method:
10 loops, best of 3: 596 ms per loop
max method:
10 loops, best of 3: 682 ms per loop
max inplace method:
10 loops, best of 3: 602 ms per loop

In-place maximum method is only a bit faster than the maximum method, and it may because it omits the variable assignment for 'out'. And it's still slower than the multiplication method.
And since you're implementing the ReLU func. You may have to save the 'x' for backprop through relu. E.g.:

def relu_backward(dout, cache):
    x = cache
    dx = np.where(x > 0, dout, 0)
    return dx

So i recommend you to use multiplication method.

Invalid use side-effecting operator Insert within a function

Disclaimer: This is not a solution, it is more of a hack to test out something. User-defined functions cannot be used to perform actions that modify the database state.

I found one way to make insert or update using sqlcmd.exe so you need just to replace the code inside @sql variable.

CREATE FUNCTION [dbo].[_tmp_func](@orderID NVARCHAR(50))
RETURNS INT
AS
BEGIN
DECLARE @sql varchar(4000), @cmd varchar(4000)
SELECT @sql = 'INSERT INTO _ord (ord_Code) VALUES (''' + @orderID + ''') '
SELECT @cmd = 'sqlcmd -S ' + @@servername +
              ' -d ' + db_name() + ' -Q "' + @sql + '"'
EXEC master..xp_cmdshell @cmd, 'no_output'
RETURN 1
END

Why does JSHint throw a warning if I am using const?

To fix this in Dreamweaver CC 2018, I went to preferences, edit rule set - select JS, edit/apply changes, find "esnext" and changed the false setting to true. It worked for me after hours of research. Hope it helps others.

How to set shadows in React Native for android?

You can use my react-native-simple-shadow-view

  • This enables almost identical shadow in Android as in iOS
  • No need to use elevation, works with the same shadow parameters of iOS (shadowColor, shadowOpacity, shadowRadius, offset, etc.) so you don't need to write platform specific shadow styles
  • Can be used with semi-transparent views
  • Supported in android 18 and up

isset() and empty() - what to use

In your particular case: if ($var).

You need to use isset if you don't know whether the variable exists or not. Since you declared it on the very first line though, you know it exists, hence you don't need to, nay, should not use isset.

The same goes for empty, only that empty also combines a check for the truthiness of the value. empty is equivalent to !isset($var) || !$var and !empty is equivalent to isset($var) && $var, or isset($var) && $var == true.

If you only want to test a variable that should exist for truthiness, if ($var) is perfectly adequate and to the point.

How do I import a .dmp file into Oracle?

imp system/system-password@SID file=directory-you-selected\FILE.dmp log=log-dir\oracle_load.log fromuser=infodba touser=infodba commit=Y

Inline instantiation of a constant List

You'll need to use a static readonly list instead. And if you want the list to be immutable then you might want to consider using ReadOnlyCollection<T> rather than List<T>.

private static readonly ReadOnlyCollection<string> _metrics =
    new ReadOnlyCollection<string>(new[]
        {
            SourceFile.LOC,
            SourceFile.MCCABE,
            SourceFile.NOM,
            SourceFile.NOA,
            SourceFile.FANOUT,
            SourceFile.FANIN,
            SourceFile.NOPAR,
            SourceFile.NDC,
            SourceFile.CALLS
        });

public static ReadOnlyCollection<string> Metrics
{
    get { return _metrics; }
}

Node.JS: Getting error : [nodemon] Internal watch failed: watch ENOSPC

in my case closing the visual studio code then starting the server did the trick

Operating system - ubuntu 16.4 lts

node.js version - 8.11.1

npm version - 6.0.0

How to use __doPostBack()

This is how I do it

    public void B_ODOC_OnClick(Object sender, EventArgs e)
    {
        string script="<script>__doPostBack(\'fileView$ctl01$OTHDOC\',\'{\"EventArgument\":\"OpenModal\",\"EncryptedData\":null}\');</script>";
        Page.ClientScript.RegisterStartupScript(this.GetType(),"JsOtherDocuments",script);               
    }

Run script with rc.local: script works, but not at boot

In this example of a rc.local script I use io redirection at the very first line of execution to my own log file:

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

exec 2> /tmp/rc.local.log  # send stderr from rc.local to a log file
exec 1>&2                      # send stdout to the same log file
set -x                         # tell sh to display commands before execution

/opt/stuff/somefancy.error.script.sh

exit 0

Undefined reference to main - collect2: ld returned 1 exit status

In my case it was just because I had not Saved the source file and was trying to compile a empty file .

sqlite copy data from one table to another

INSERT INTO Destination SELECT * FROM Source;

See SQL As Understood By SQLite: INSERT for a formal definition.

What is the difference between bool and Boolean types in C#

Perhaps bool is a tad "lighter" than Boolean; Interestingly, changing this:

namespace DuckbillServerWebAPI.Models
{
    public class Expense
    {
        . . .
        public bool CanUseOnItems { get; set; }
    }
}

...to this:

namespace DuckbillServerWebAPI.Models
{
    public class Expense
    {
        . . .
        public Boolean CanUseOnItems { get; set; }
    }
}

...caused my cs file to sprout a "using System;" Changing the type back to "bool" caused the using clause's hair to turn grey.

(Visual Studio 2010, WebAPI project)

Getting a count of rows in a datatable that meet certain criteria

One easy way to accomplish this is combining what was posted in the original post into a single statement:

int numberOfRecords = dtFoo.Select("IsActive = 'Y'").Length;

Another way to accomplish this is using Linq methods:

int numberOfRecords = dtFoo.AsEnumerable().Where(x => x["IsActive"].ToString() == "Y").ToList().Count;

Note this requires including System.Linq.

What does FETCH_HEAD in Git mean?

FETCH_HEAD is a short-lived ref, to keep track of what has just been fetched from the remote repository.

Actually, ... not always considering that, with Git 2.29 (Q4 2020), "git fetch"(man) learned --no-write-fetch-head option to avoid writing the FETCH_HEAD file.

See commit 887952b (18 Aug 2020) by Junio C Hamano (gitster).
(Merged by Junio C Hamano -- gitster -- in commit b556050, 24 Aug 2020)

fetch: optionally allow disabling FETCH_HEAD update

Signed-off-by: Derrick Stolee

If you run fetch but record the result in remote-tracking branches, and either if you do nothing with the fetched refs (e.g. you are merely mirroring) or if you always work from the remote-tracking refs (e.g. you fetch and then merge origin/branchname separately), you can get away with having no FETCH_HEAD at all.

Teach "git fetch"(man) a command line option "--[no-]write-fetch-head".

  • The default is to write FETCH_HEAD, and the option is primarily meant to be used with the "--no-" prefix to override this default, because there is no matching fetch.writeFetchHEAD configuration variable to flip the default to off (in which case, the positive form may become necessary to defeat it).

Note that under "--dry-run" mode, FETCH_HEAD is never written; otherwise you'd see list of objects in the file that you do not actually have.

Passing --write-fetch-head does not force [git fetch](https://github.com/git/git/blob/887952b8c680626f4721cb5fa57704478801aca4/Documentation/git-fetch.txt)<sup>([man](https://git-scm.com/docs/git-fetch))</sup> to write the file.

fetch-options now includes in its man page:

--[no-]write-fetch-head

Write the list of remote refs fetched in the FETCH_HEAD file directly under $GIT_DIR.
This is the default.

Passing --no-write-fetch-head from the command line tells Git not to write the file.
Under --dry-run option, the file is never written.


Consider also, still with Git 2.29 (Q4 2020), the FETCH_HEAD is now always read from the filesystem regardless of the ref backend in use, as its format is much richer than the normal refs, and written directly by "git fetch"(man) as a plain file..

See commit e811530, commit 5085aef, commit 4877c6c, commit e39620f (19 Aug 2020) by Han-Wen Nienhuys (hanwen).
(Merged by Junio C Hamano -- gitster -- in commit 98df75b, 27 Aug 2020)

refs: read FETCH_HEAD and MERGE_HEAD generically

Signed-off-by: Han-Wen Nienhuys

The FETCH_HEAD and MERGE_HEAD refs must be stored in a file, regardless of the type of ref backend. This is because they can hold more than just a single ref.

To accomodate them for alternate ref backends, read them from a file generically in refs_read_raw_ref().


With Git 2.29 (Q4 2020), Updates to on-demand fetching code in lazily cloned repositories.

See commit db3c293 (02 Sep 2020), and commit 9dfa8db, commit 7ca3c0a, commit 5c3b801, commit abcb7ee, commit e5b9421, commit 2b713c2, commit cbe566a (17 Aug 2020) by Jonathan Tan (jhowtan).
(Merged by Junio C Hamano -- gitster -- in commit b4100f3, 03 Sep 2020)

fetch: no FETCH_HEAD display if --no-write-fetch-head

Signed-off-by: Jonathan Tan

887952b8c6 ("fetch: optionally allow disabling FETCH_HEAD update", 2020-08-18, Git v2.29.0 -- merge listed in batch #10) introduced the ability to disable writing to FETCH_HEAD during fetch, but did not suppress the "<source> -> FETCH_HEAD" message when this ability is used.

This message is misleading in this case, because FETCH_HEAD is not written.

Also, because "fetch" is used to lazy-fetch missing objects in a partial clone, this significantly clutters up the output in that case since the objects to be fetched are potentially numerous.

Therefore, suppress this message when --no-write-fetch-head is passed (but not when --dry-run is set).

printf a variable in C

As Shafik already wrote you need to use the right format because scanf gets you a char. Don't hesitate to look here if u aren't sure about the usage: http://www.cplusplus.com/reference/cstdio/printf/

Hint: It's faster/nicer to write x=x+1; the shorter way: x++;

Sorry for answering what's answered just wanted to give him the link - the site was really useful to me all the time dealing with C.

Difference between ApiController and Controller in ASP.NET MVC

Quick n Short Answer

If you want to return a view, you should be in "Controller".

Normal Controller - ASP.NET MVC: you deal with normal "Controller" if you are in ASP.net Web Application. You can create Controller-Actions and you can return Views().

ApiController Controller: you create ApiControllers when you are developing ASP.net REST APIs. you can't return Views (though you can return Json/Data for HTML as string). These apis are considered as backend and their functions are called to return data not the view

Please dont forgt to mark this as answer, take care

More Details here

Get the last element of a std::string

You could write a function template back that delegates to the member function for ordinary containers and a normal function that implements the missing functionality for strings:

template <typename C>
typename C::reference back(C& container)
{
    return container.back();
}

template <typename C>
typename C::const_reference back(const C& container)
{
    return container.back();
}

char& back(std::string& str)
{
    return *(str.end() - 1);
}

char back(const std::string& str)
{
    return *(str.end() - 1);
}

Then you can just say back(foo) without worrying whether foo is a string or a vector.

Insert ellipsis (...) into HTML tag if content too wide

I built this code using a number of other posts, with the following enhancements:

  1. It uses a binary search to find the text length that is just right.
  2. It handles cases where the ellipsis element(s) are initially hidden by setting up a one-shot show event that re-runs the ellipsis code when the item is first displayed. This is handy for master-detail views or tree-views where some items aren't initially displayed.
  3. It optionally adds a title attribute with the original text for a hoverover effect.
  4. Added display: block to the style, so spans work
  5. It uses the ellipsis character instead of 3 periods.
  6. It auto-runs the script for anything with the .ellipsis class

CSS:

.ellipsis {
        white-space: nowrap;
        overflow: hidden;
        display: block;
}

.ellipsis.multiline {
        white-space: normal;
}

jquery.ellipsis.js

(function ($) {

    // this is a binary search that operates via a function
    // func should return < 0 if it should search smaller values
    // func should return > 0 if it should search larger values
    // func should return = 0 if the exact value is found
    // Note: this function handles multiple matches and will return the last match
    // this returns -1 if no match is found
    function binarySearch(length, func) {
        var low = 0;
        var high = length - 1;
        var best = -1;
        var mid;

        while (low <= high) {
            mid = ~ ~((low + high) / 2); //~~ is a fast way to convert something to an int
            var result = func(mid);
            if (result < 0) {
                high = mid - 1;
            } else if (result > 0) {
                low = mid + 1;
            } else {
                best = mid;
                low = mid + 1;
            }
        }

        return best;
    }

    // setup handlers for events for show/hide
    $.each(["show", "toggleClass", "addClass", "removeClass"], function () {

        //get the old function, e.g. $.fn.show   or $.fn.hide
        var oldFn = $.fn[this];
        $.fn[this] = function () {

            // get the items that are currently hidden
            var hidden = this.find(":hidden").add(this.filter(":hidden"));

            // run the original function
            var result = oldFn.apply(this, arguments);

            // for all of the hidden elements that are now visible
            hidden.filter(":visible").each(function () {
                // trigger the show msg
                $(this).triggerHandler("show");
            });

            return result;
        };
    });

    // create the ellipsis function
    // when addTooltip = true, add a title attribute with the original text
    $.fn.ellipsis = function (addTooltip) {

        return this.each(function () {
            var el = $(this);

            if (el.is(":visible")) {

                if (el.css("overflow") === "hidden") {
                    var content = el.html();
                    var multiline = el.hasClass('multiline');
                    var tempElement = $(this.cloneNode(true))
                        .hide()
                        .css('position', 'absolute')
                        .css('overflow', 'visible')
                        .width(multiline ? el.width() : 'auto')
                        .height(multiline ? 'auto' : el.height())
                    ;

                    el.after(tempElement);

                    var tooTallFunc = function () {
                        return tempElement.height() > el.height();
                    };

                    var tooWideFunc = function () {
                        return tempElement.width() > el.width();
                    };

                    var tooLongFunc = multiline ? tooTallFunc : tooWideFunc;

                    // if the element is too long...
                    if (tooLongFunc()) {

                        var tooltipText = null;
                        // if a tooltip was requested...
                        if (addTooltip) {
                            // trim leading/trailing whitespace
                            // and consolidate internal whitespace to a single space
                            tooltipText = $.trim(el.text()).replace(/\s\s+/g, ' ');
                        }

                        var originalContent = content;

                        var createContentFunc = function (i) {
                            content = originalContent.substr(0, i);
                            tempElement.html(content + "…");
                        };

                        var searchFunc = function (i) {
                            createContentFunc(i);
                            if (tooLongFunc()) {
                                return -1;
                            }
                            return 0;
                        };

                        var len = binarySearch(content.length - 1, searchFunc);

                        createContentFunc(len);

                        el.html(tempElement.html());

                        // add the tooltip if appropriate
                        if (tooltipText !== null) {
                            el.attr('title', tooltipText);
                        }
                    }

                    tempElement.remove();
                }
            }
            else {
                // if this isn't visible, then hook up the show event
                el.one('show', function () {
                    $(this).ellipsis(addTooltip);
                });
            }
        });
    };

    // ellipsification for items with an ellipsis
    $(document).ready(function () {
        $('.ellipsis').ellipsis(true);
    });

} (jQuery));

How do I filter an array with TypeScript in Angular 2?

You can check an example in Plunker over here plunker example filters

filter() {

    let storeId = 1;
    this.bookFilteredList = this.bookList
                                .filter((book: Book) => book.storeId === storeId);
    this.bookList = this.bookFilteredList; 
}

toggle show/hide div with button?

Here's a plain Javascript way of doing toggle:

<script>
  var toggle = function() {
  var mydiv = document.getElementById('newpost');
  if (mydiv.style.display === 'block' || mydiv.style.display === '')
    mydiv.style.display = 'none';
  else
    mydiv.style.display = 'block'
  }
</script>

<div id="newpost">asdf</div>
<input type="button" value="btn" onclick="toggle();">

How to change root logging level programmatically for logback

I seem to be having success doing

org.jboss.logmanager.Logger logger = org.jboss.logmanager.Logger.getLogger("");
logger.setLevel(java.util.logging.Level.ALL);

Then to get detailed logging from netty, the following has done it

org.slf4j.impl.SimpleLogger.setLevel(org.slf4j.impl.SimpleLogger.TRACE);

'JSON' is undefined error in JavaScript in Internet Explorer

Maybe it is not what you are looking for, but I had a similar problem and i solved it including JSON 2 to my application:

https://github.com/douglascrockford/JSON-js

Other browsers natively implements JSON but IE < 8 (also IE 8 compatibility mode) does not, that's why you need to include it.

Here is a related question: JSON on IE6 (IE7)

UPDATE

the JSON parser has been updated so you should use the new one: http://bestiejs.github.io/json3/

How to find duplicate records in PostgreSQL

From "Find duplicate rows with PostgreSQL" here's smart solution:

select * from (
  SELECT id,
  ROW_NUMBER() OVER(PARTITION BY column1, column2 ORDER BY id asc) AS Row
  FROM tbl
) dups
where 
dups.Row > 1

Equivalent of SQL ISNULL in LINQ?

Since aa is the set/object that might be null, can you check aa == null ?

(aa / xx might be interchangeable (a typo in the question); the original question talks about xx but only defines aa)

i.e.

select new {
    AssetID = x.AssetID,
    Status = aa == null ? (bool?)null : aa.Online; // a Nullable<bool>
}

or if you want the default to be false (not null):

select new {
    AssetID = x.AssetID,
    Status = aa == null ? false : aa.Online;
}

Update; in response to the downvote, I've investigated more... the fact is, this is the right approach! Here's an example on Northwind:

        using(var ctx = new DataClasses1DataContext())
        {
            ctx.Log = Console.Out;
            var qry = from boss in ctx.Employees
                      join grunt in ctx.Employees
                          on boss.EmployeeID equals grunt.ReportsTo into tree
                      from tmp in tree.DefaultIfEmpty()
                      select new
                             {
                                 ID = boss.EmployeeID,
                                 Name = tmp == null ? "" : tmp.FirstName
                        };
            foreach(var row in qry)
            {
                Console.WriteLine("{0}: {1}", row.ID, row.Name);
            }
        }

And here's the TSQL - pretty much what we want (it isn't ISNULL, but it is close enough):

SELECT [t0].[EmployeeID] AS [ID],
    (CASE
        WHEN [t2].[test] IS NULL THEN CONVERT(NVarChar(10),@p0)
        ELSE [t2].[FirstName]
     END) AS [Name]
FROM [dbo].[Employees] AS [t0]
LEFT OUTER JOIN (
    SELECT 1 AS [test], [t1].[FirstName], [t1].[ReportsTo]
    FROM [dbo].[Employees] AS [t1]
    ) AS [t2] ON ([t0].[EmployeeID]) = [t2].[ReportsTo]
-- @p0: Input NVarChar (Size = 0; Prec = 0; Scale = 0) []
-- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 3.5.30729.1

QED?

Vbscript list all PDF files in folder and subfolders

The file extension may be case sentive...but the code works.

Set objFSO = CreateObject("Scripting.FileSystemObject")
  objStartFolder = "C:\Dev\"

  Set objFolder = objFSO.GetFolder(objStartFolder)
  Wscript.Echo objFolder.Path

  Set colFiles = objFolder.Files

  For Each objFile in colFiles
  strFileName = objFile.Name

  If objFSO.GetExtensionName(strFileName) = "pdf" Then
      Wscript.Echo objFile.Name
  End If

  Next
  Wscript.Echo

  ShowSubfolders objFSO.GetFolder(objStartFolder)

  Sub ShowSubFolders(Folder)
     For Each Subfolder in Folder.SubFolders
          Wscript.Echo Subfolder.Path
          Set objFolder = objFSO.GetFolder(Subfolder.Path)
          Set colFiles = objFolder.Files
          For Each objFile in colFiles
              Wscript.Echo objFile.Name
          Next
          Wscript.Echo
          ShowSubFolders Subfolder
      Next
  End Sub

pull out p-values and r-squared from a linear regression

I came across this question while exploring suggested solutions for a similar problem; I presume that for future reference it may be worthwhile to update the available list of answer with a solution utilising the broom package.

Sample code

x = cumsum(c(0, runif(100, -1, +1)))
y = cumsum(c(0, runif(100, -1, +1)))
fit = lm(y ~ x)
require(broom)
glance(fit)

Results

>> glance(fit)
  r.squared adj.r.squared    sigma statistic    p.value df    logLik      AIC      BIC deviance df.residual
1 0.5442762     0.5396729 1.502943  118.2368 1.3719e-18  2 -183.4527 372.9055 380.7508 223.6251          99

Side notes

I find the glance function is useful as it neatly summarises the key values. The results are stored as a data.frame which makes further manipulation easy:

>> class(glance(fit))
[1] "data.frame"

How to declare a variable in a PostgreSQL query

You could also try this in PLPGSQL:

DO $$
DECLARE myvar integer;
BEGIN
    SELECT 5 INTO myvar;

    DROP TABLE IF EXISTS tmp_table;
    CREATE TABLE tmp_table AS
    SELECT * FROM yourtable WHERE   id = myvar;
END $$;

SELECT * FROM tmp_table;

The above requires Postgres 9.0 or later.

How do I delete an item or object from an array using ng-click?

Using $index works perfectly well in basic cases, and @charlietfl's answer is great. But sometimes, $index isn't enough.

Imagine you have a single array, which you're presenting in two different ng-repeat's. One of those ng-repeat's is filtered for objects that have a truthy property, and the other is filtered for a falsy property. Two different filtered arrays are being presented, which derive from a single original array. (Or, if it helps to visualize: perhaps you have a single array of people, and you want one ng-repeat for the women in that array, and another for the men in that same array.) Your goal: delete reliably from the original array, using information from the members of the filtered arrays.

In each of those filtered arrays, $index won't be the index of the item within the original array. It'll be the index in the filtered sub-array. So, you won't be able to tell the person's index in the original people array, you'll only know the $index from the women or men sub-array. Try to delete using that, and you'll have items disappearing from everywhere except where you wanted. What to do?

If you're lucky enough be using a data model includes a unique identifier for each object, then use that instead of $index, to find the object and splice it out of the main array. (Use my example below, but with that unique identifier.) But if you're not so lucky?

Angular actually augments each item in an ng-repeated array (in the main, original array) with a unique property called $$hashKey. You can search the original array for a match on the $$hashKey of the item you want to delete, and get rid of it that way.

Note that $$hashKey is an implementation detail, not included in the published API for ng-repeat. They could remove support for that property at any time. But probably not. :-)

$scope.deleteFilteredItem = function(hashKey, sourceArray){
  angular.forEach(sourceArray, function(obj, index){
    // sourceArray is a reference to the original array passed to ng-repeat, 
    // rather than the filtered version. 
    // 1. compare the target object's hashKey to the current member of the iterable:
    if (obj.$$hashKey === hashKey) {
      // remove the matching item from the array
      sourceArray.splice(index, 1);
      // and exit the loop right away
      return;
    };
  });
}

Invoke with:

ng-click="deleteFilteredItem(item.$$hashKey, refToSourceArray)"

EDIT: Using a function like this, which keys on the $$hashKey instead of a model-specific property name, also has the significant added advantage of making this function reusable across different models and contexts. Provide it with your array reference, and your item reference, and it should just work.

Unable to create Genymotion Virtual Device

Solved!!

I am using OS X 10.9 (Mavericks), Genymotion v1.3.1

While adding the device, instead of adding Nexus, I added Galaxy S4/HTC One/Xperia Z - 4.2.2 with Google Apps.

This one just worked.

How to split data into 3 sets (train, validation and test)?

However, one approach to dividing the dataset into train, test, cv with 0.6, 0.2, 0.2 would be to use the train_test_split method twice.

from sklearn.model_selection import train_test_split

x, x_test, y, y_test = train_test_split(xtrain,labels,test_size=0.2,train_size=0.8)
x_train, x_cv, y_train, y_cv = train_test_split(x,y,test_size = 0.25,train_size =0.75)

Click event doesn't work on dynamically generated elements

The Jquery .on works ok but I had some problems with the rendering implementing some of the solutions above. My problem using the .on is that somehow it was rendering the events differently than the .hover method.

Just fyi for anyone else that may also have the problem. I solved my problem by re-registering the hover event for the dynamically added item:

re-register the hover event because hover doesn't work for dynamically created items. so every time i create the new/dynamic item i add the hover code again. works perfectly

$('#someID div:last').hover(
    function() {
       //...
    },
    function() {
       //...
    }
);

How to hide underbar in EditText

Set background to null.

android:background="@null"

jQuery to retrieve and set selected option value of html select element

$( "#myId option:selected" ).text(); will give you the text that you selected in the drop down element. either way you can change it to .val(); to get the value of it . check the below coding

<select id="myId">
    <option value="1">Mr</option>
    <option value="2">Mrs</option>
    <option value="3">Ms</option>`
    <option value="4">Dr</option>
    <option value="5">Prof</option>
</select>

Rails 4 - Strong Parameters - Nested Objects

Permitting a nested object :

params.permit( {:school => [:id , :name]}, 
               {:student => [:id, 
                            :name, 
                            :address, 
                            :city]},
                {:records => [:marks, :subject]})

Difference between java.lang.RuntimeException and java.lang.Exception

There are two types of exception, You can recover from checked exception if you get such kind of exception. Runtime exception are irrecoverable, runtime exceptions are programming errors, and programmer should take care of it while writing the code, and continue execution of this might give you incorrect result. Runtime exceptions are about violating precondition ex. you have an array of size 10, and you are trying to access 11 th element, it will throw ArrayIndexOutOfBoundException

How to define static constant in a class in swift

If you actually want a static property of your class, that isn't currently supported in Swift. The current advice is to get around that by using global constants:

let testStr = "test"
let testStrLen = countElements(testStr)

class MyClass {
    func myFunc() {
    }
}

If you want these to be instance properties instead, you can use a lazy stored property for the length -- it will only get evaluated the first time it is accessed, so you won't be computing it over and over.

class MyClass {
    let testStr: String = "test"
    lazy var testStrLen: Int = countElements(self.testStr)

    func myFunc() {
    }
}

Getting last month's date in php

It works for me:

Today is: 31/03/2012

echo date("Y-m-d", strtotime(date('m', mktime() - 31*3600*24).'/01/'.date('Y').' 00:00:00')); // 2012-02-01
echo  date("Y-m-d", mktime() - 31*3600*24); // 2012-02-29

Add new value to an existing array in JavaScript

There are several ways:

Instantiating the array:

var arr;

arr = new Array(); // empty array

// ---

arr = [];          // empty array

// ---

arr = new Array(3);
alert(arr.length);  // 3
alert(arr[0]); // undefined

// ---

arr = [3];
alert(arr.length);  // 1
alert(arr[0]); // 3

Pushing to the array:

arr = [3];     // arr == [3]
arr[1] = 4;    // arr == [3, 4]
arr[2] = 5;    // arr == [3, 4, 5]
arr[4] = 7;    // arr == [3, 4, 5, undefined, 7]

// ---

arr = [3];
arr.push(4);        // arr == [3, 4]
arr.push(5);        // arr == [3, 4, 5]
arr.push(6, 7, 8);  // arr == [3, 4, 5, 6, 7, 8]

Using .push() is the better way to add to an array, since you don't need to know how many items are already there, and you can add many items in one function call.

Check if list is empty in C#

    If (list.Count==0){
      //you can show your error messages here
    } else {
      //here comes your datagridview databind 
    }

You can make your datagrid visible false and make it visible on the else section.

What is a elegant way in Ruby to tell if a variable is a Hash or an Array?

I use this:

@var.respond_to?(:keys)

It works for Hash and ActiveSupport::HashWithIndifferentAccess.

How can I comment a single line in XML?

It is the same as the HTML or JavaScript block comments:

<!-- The to-be-commented XML block goes here. -->

Address in mailbox given [] does not comply with RFC 2822, 3.6.2. when email is in a variable

I have faced the same problem and I have fixed. Please make sure some things as written bellow :

   Mail::send('emails.auth.activate', array('link'=> URL::route('account-activate', $code),'username'=>$user->username),function($message) use ($user) {
                        $message->to($user->email , $user->username)->subject('Active your account !');

                    });

This should be your emails.activation

    Hello {{ $username }} , <br> <br> <br>

    We have created your account ! Awesome ! Please activate by clicking the   following link <br> <br> <br>
   ----- <br>
      {{ $link }} <br> <br> <br>
       ---- 

The answer to your why you can't call $email variable into your mail sending function. You need to call $user variable then you can write your desired variable as $user->variable

Thank You :)