Programs & Examples On #Navicat

Navicat is a series of graphical database management and development software produced by PremiumSoft CyberTech Ltd. for MySQL, MariaDB, Oracle, SQLite, PostgreSQL and Microsoft SQL Server.

How to send email from MySQL 5.1

If you have an SMTP service running, you can outfile to the drop directory. If you have high volume, you may result with duplicate file names, but there are ways to avoid that.

Otherwise, you will need to create a UDF.

Here's a sample trigger solution:

CREATE TRIGGER test.autosendfromdrop BEFORE INSERT ON test.emaildrop
FOR EACH ROW BEGIN
      /* START THE WRITING OF THE EMAIL FILE HERE*/      
      SELECT  concat("To: ",NEW.To),
              concat("From: ",NEW.From),
              concat("Subject: ",NEW.Subject),
              NEW.Body
          INTO OUTFILE 
                   "C:\\inetpub\\mailroot\\pickup\\mail.txt" 
              FIELDS TERMINATED by '\r\n' ESCAPED BY '';            
END;

To markup the message body you will need something like this...

CREATE FUNCTION `HTMLBody`(Msg varchar(8192)) 
    RETURNS varchar(17408) CHARSET latin1 DETERMINISTIC
BEGIN
  declare tmpMsg varchar(17408);
  set tmpMsg = cast(concat(
      'Date: ',date_format(NOW(),'%e %b %Y %H:%i:%S -0600'),'\r\n',
      'MIME-Version: 1.0','\r\n',
      'Content-Type: multipart/alternative;','\r\n',
      ' boundary=\"----=_NextPart_000_0000_01CA4B3F.8C263EE0\"','\r\n',
      'Content-Class: urn:content-classes:message','\r\n',
      'Importance: normal','\r\n',
      'Priority: normal','\r\n','','\r\n','','\r\n',
      'This is a multi-part message in MIME format.','\r\n','','\r\n',
      '------=_NextPart_000_0000_01CA4B3F.8C263EE0','\r\n',
      'Content-Type: text/plain;','\r\n',
      '  charset=\"iso-8859-1\"','\r\n',
      'Content-Transfer-Encoding: 7bit','\r\n','','\r\n','','\r\n',
      Msg,
      '\r\n','','\r\n','','\r\n',
      '------=_NextPart_000_0000_01CA4B3F.8C263EE0','\r\n',
      'Content-Type: text/html','\r\n',
      'Content-Transfer-Encoding: 7bit','\r\n','','\r\n',
      Msg,
      '\r\n','------=_NextPart_000_0000_01CA4B3F.8C263EE0--'
      ) as char);
  RETURN tmpMsg;
END ;

Error: Tablespace for table xxx exists. Please DISCARD the tablespace before IMPORT

Deleting/Moving tablename.ibd sure did not work for me.

How I solved it

Since I was going to delete the corrupted and non existing table, I took a backup of the other tables by going to phpmyadmin->database->export->selected tables to backup->export(as .sql).

After that I selected the database icon next to database name and then dropped it. Created a new database. Select your new database->import-> Select the file you downloaded earlier->click import. Now I have my old working tables and have the corrupted table deleted. Now I just create the table that was throwing the error.

Likely I had an earlier backup of the corrupted table.

HTML how to clear input using javascript?

You don't need to bother with that. Just write

<input type="text" name="email" placeholder="[email protected]" size="30">

replace the value with placeholder

Add Bean Programmatically to Spring Web App Context

In Spring 3.0 you can make your bean implement BeanDefinitionRegistryPostProcessor and add new beans via BeanDefinitionRegistry.

In previous versions of Spring you can do the same thing in BeanFactoryPostProcessor (though you need to cast BeanFactory to BeanDefinitionRegistry, which may fail).

In Python, what is the difference between ".append()" and "+= []"?

+= is an assignment. When you use it you're really saying ‘some_list2= some_list2+['something']’. Assignments involve rebinding, so:

l= []

def a1(x):
    l.append(x) # works

def a2(x):
    l= l+[x] # assign to l, makes l local
             # so attempt to read l for addition gives UnboundLocalError

def a3(x):
    l+= [x]  # fails for the same reason

The += operator should also normally create a new list object like list+list normally does:

>>> l1= []
>>> l2= l1

>>> l1.append('x')
>>> l1 is l2
True

>>> l1= l1+['x']
>>> l1 is l2
False

However in reality:

>>> l2= l1
>>> l1+= ['x']
>>> l1 is l2
True

This is because Python lists implement __iadd__() to make a += augmented assignment short-circuit and call list.extend() instead. (It's a bit of a strange wart this: it usually does what you meant, but for confusing reasons.)

In general, if you're appending/extended an existing list, and you want to keep the reference to the same list (instead of making a new one), it's best to be explicit and stick with the append()/extend() methods.

How to use Class<T> in Java?

In java <T> means Generic class. A Generic Class is a class which can work on any type of data type or in other words we can say it is data type independent.

public class Shape<T> {
    // T stands for "Type"
    private T t;

    public void set(T t) { this.t = t; }
    public T get() { return t; }
}

Where T means type. Now when you create instance of this Shape class you will need to tell the compiler for what data type this will be working on.

Example:

Shape<Integer> s1 = new Shape();
Shape<String> s2 = new Shape();

Integer is a type and String is also a type.

<T> specifically stands for generic type. According to Java Docs - A generic type is a generic class or interface that is parameterized over types.

How to list only files and not directories of a directory Bash?

You can also use ls with grep or egrep and put it in your profile as an alias:

ls -l | egrep -v '^d'
ls -l | grep -v '^d'

module.exports vs. export default in Node.js and ES6

The issue is with

  • how ES6 modules are emulated in CommonJS
  • how you import the module

ES6 to CommonJS

At the time of writing this, no environment supports ES6 modules natively. When using them in Node.js you need to use something like Babel to convert the modules to CommonJS. But how exactly does that happen?

Many people consider module.exports = ... to be equivalent to export default ... and exports.foo ... to be equivalent to export const foo = .... That's not quite true though, or at least not how Babel does it.

ES6 default exports are actually also named exports, except that default is a "reserved" name and there is special syntax support for it. Lets have a look how Babel compiles named and default exports:

// input
export const foo = 42;
export default 21;

// output
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
var foo = exports.foo = 42;
exports.default = 21; 

Here we can see that the default export becomes a property on the exports object, just like foo.

Import the module

We can import the module in two ways: Either using CommonJS or using ES6 import syntax.

Your issue: I believe you are doing something like:

var bar = require('./input');
new bar();

expecting that bar is assigned the value of the default export. But as we can see in the example above, the default export is assigned to the default property!

So in order to access the default export we actually have to do

var bar = require('./input').default;

If we use ES6 module syntax, namely

import bar from './input';
console.log(bar);

Babel will transform it to

'use strict';

var _input = require('./input');

var _input2 = _interopRequireDefault(_input);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

console.log(_input2.default);

You can see that every access to bar is converted to access .default.

Bind event to right mouse click

I found this answer here and I'm using it like this.

Code from my Library:

$.fn.customContextMenu = function(callBack){
    $(this).each(function(){
        $(this).bind("contextmenu",function(e){
             e.preventDefault();
             callBack();
        });
    }); 
}

Code from my page's script:

$("#newmagazine").customContextMenu(function(){
    alert("some code");
});

ngFor with index as value in attribute

The other answers are correct but you can omit the [attr.data-index] altogether and just use

<ul>
    <li *ngFor="let item of items; let i = index">{{i + 1}}</li>
</ul

How can I install a previous version of Python 3 in macOS using homebrew?

What I did was first I installed python 3.7

brew install python3
brew unlink python

then I installed python 3.6.5 using above link

brew install --ignore-dependencies https://raw.githubusercontent.com/Homebrew/homebrew-core/f2a764ef944b1080be64bd88dca9a1d80130c558/Formula/python.rb --ignore-dependencies

After that I ran brew link --overwrite python. Now I have all pythons in the system to create the virtual environments.

mian@tdowrick2~ $ python --version
Python 2.7.10
mian@tdowrick2~ $ python3.7 --version
Python 3.7.1
mian@tdowrick2~ $ python3.6 --version
Python 3.6.5

To create Python 3.7 virtual environment.

mian@tdowrick2~ $ virtualenv -p python3.7 env
Already using interpreter /Library/Frameworks/Python.framework/Versions/3.7/bin/python3.7
Using base prefix '/Library/Frameworks/Python.framework/Versions/3.7'
New python executable in /Users/mian/env/bin/python3.7
Also creating executable in /Users/mian/env/bin/python
Installing setuptools, pip, wheel...
done.
mian@tdowrick2~ $ source env/bin/activate
(env) mian@tdowrick2~ $ python --version
Python 3.7.1
(env) mian@tdowrick2~ $ deactivate

To create Python 3.6 virtual environment

mian@tdowrick2~ $ virtualenv -p python3.6 env
Running virtualenv with interpreter /usr/local/bin/python3.6
Using base prefix '/usr/local/Cellar/python/3.6.5_1/Frameworks/Python.framework/Versions/3.6'
New python executable in /Users/mian/env/bin/python3.6
Not overwriting existing python script /Users/mian/env/bin/python (you must use /Users/mian/env/bin/python3.6)
Installing setuptools, pip, wheel...
done.
mian@tdowrick2~ $ source env/bin/activate
(env) mian@tdowrick2~ $ python --version
Python 3.6.5
(env) mian@tdowrick2~ $ 

Display current time in 12 hour format with AM/PM

SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MMM-yy hh.mm.ss.S aa");
String formattedDate = dateFormat.format(new Date()).toString();
System.out.println(formattedDate);

Output: 11-Sep-13 12.25.15.375 PM

C++ Calling a function from another class

class B is only declared but not defined at the beginning, which is what the compiler complains about. The root cause is that in class A's Call Function, you are referencing instance b of type B, which is incomplete and undefined. You can modify source like this without introducing new file(just for sake of simplicity, not recommended in practice):

using namespace std;

class A 
{
public:

    void CallFunction ();
};

class B: public A
{
public:
    virtual void bFunction()
    {
        //stuff done here
    }
};


 // postpone definition of CallFunction here

 void A::CallFunction ()
 {
     B b;
     b.bFunction();
 }

How to sort a HashMap in Java

Do you have to use a HashMap? If you only need the Map Interface use a TreeMap


If you want to sort by comparing values in the HashMap. You have to write code to do this, if you want to do it once you can sort the values of your HashMap:

Map<String, Person> people = new HashMap<>();
Person jim = new Person("Jim", 25);
Person scott = new Person("Scott", 28);
Person anna = new Person("Anna", 23);

people.put(jim.getName(), jim);
people.put(scott.getName(), scott);
people.put(anna.getName(), anna);

// not yet sorted
List<Person> peopleByAge = new ArrayList<>(people.values());

Collections.sort(peopleByAge, Comparator.comparing(Person::getAge));

for (Person p : peopleByAge) {
    System.out.println(p.getName() + "\t" + p.getAge());
}

If you want to access this sorted list often, then you could insert your elements into a HashMap<TreeSet<Person>>, though the semantics of sets and lists are a bit different.

How do you uninstall MySQL from Mac OS X?

OS version: 10.14.6 MYSQL version: 8.0.14

Goto System preferences -> MYSQLenter image description here

Stop MySQL server

enter image description here

One option will be shown here to uninstall MYSQL 8 after stopping Mysql server

Update with two tables?

It can be as follows:

UPDATE A 
SET A.`id` = (SELECT id from B WHERE A.title = B.title)

Android EditText view Floating Hint in Material Design

@andruboy's suggestion of https://gist.github.com/chrisbanes/11247418 is probably your best bet.

https://github.com/thebnich/FloatingHintEditText kind of works with appcompat-v7 v21.0.0, but since v21.0.0 does not support accent colors with subclasses of EditText, the underline of the FloatingHintEditText will be the default solid black or white. Also the padding is not optimized for the Material style EditText, so you may need to adjust it.

Java SSL: how to disable hostname verification

In case you're using apache's http-client 4:

SSLConnectionSocketFactory sslConnectionSocketFactory = 
    new SSLConnectionSocketFactory(sslContext,
             new String[] { "TLSv1.2" }, null, new HostnameVerifier() {
                    public boolean verify(String arg0, SSLSession arg1) {
                            return true;
            }
      });

What are alternatives to document.write?

As a recommended alternative to document.write you could use DOM manipulation to directly query and add node elements to the DOM.

Using group by on multiple columns

Here I am going to explain not only the GROUP clause use, but also the Aggregate functions use.

The GROUP BY clause is used in conjunction with the aggregate functions to group the result-set by one or more columns. e.g.:

-- GROUP BY with one parameter:
SELECT column_name, AGGREGATE_FUNCTION(column_name)
FROM table_name
WHERE column_name operator value
GROUP BY column_name;

-- GROUP BY with two parameters:
SELECT
    column_name1,
    column_name2,
    AGGREGATE_FUNCTION(column_name3)
FROM
    table_name
GROUP BY
    column_name1,
    column_name2;

Remember this order:

  1. SELECT (is used to select data from a database)

  2. FROM (clause is used to list the tables)

  3. WHERE (clause is used to filter records)

  4. GROUP BY (clause can be used in a SELECT statement to collect data across multiple records and group the results by one or more columns)

  5. HAVING (clause is used in combination with the GROUP BY clause to restrict the groups of returned rows to only those whose the condition is TRUE)

  6. ORDER BY (keyword is used to sort the result-set)

You can use all of these if you are using aggregate functions, and this is the order that they must be set, otherwise you can get an error.

Aggregate Functions are:

MIN() returns the smallest value in a given column

MAX() returns the maximum value in a given column.

SUM() returns the sum of the numeric values in a given column

AVG() returns the average value of a given column

COUNT() returns the total number of values in a given column

COUNT(*) returns the number of rows in a table

SQL script examples about using aggregate functions:

Let's say we need to find the sale orders whose total sale is greater than $950. We combine the HAVING clause and the GROUP BY clause to accomplish this:

SELECT 
    orderId, SUM(unitPrice * qty) Total
FROM
    OrderDetails
GROUP BY orderId
HAVING Total > 950;

Counting all orders and grouping them customerID and sorting the result ascendant. We combine the COUNT function and the GROUP BY, ORDER BY clauses and ASC:

SELECT 
    customerId, COUNT(*)
FROM
    Orders
GROUP BY customerId
ORDER BY COUNT(*) ASC;

Retrieve the category that has an average Unit Price greater than $10, using AVG function combine with GROUP BY and HAVING clauses:

SELECT 
    categoryName, AVG(unitPrice)
FROM
    Products p
INNER JOIN
    Categories c ON c.categoryId = p.categoryId
GROUP BY categoryName
HAVING AVG(unitPrice) > 10;

Getting the less expensive product by each category, using the MIN function in a subquery:

SELECT categoryId,
       productId,
       productName,
       unitPrice
FROM Products p1
WHERE unitPrice = (
                SELECT MIN(unitPrice)
                FROM Products p2
                WHERE p2.categoryId = p1.categoryId)

The following statement groups rows with the same values in both categoryId and productId columns:

SELECT 
    categoryId, categoryName, productId, SUM(unitPrice)
FROM
    Products p
INNER JOIN
    Categories c ON c.categoryId = p.categoryId
GROUP BY categoryId, productId

Determine which element the mouse pointer is on top of in JavaScript

You can use this selector to undermouse object and then manipulate it as a jQuery object:

$(':hover').last();

Angular ForEach in Angular4/Typescript?

in angular4 foreach like that. try this.

 selectChildren(data, $event) {
      let parentChecked = data.checked;
       this.hierarchicalData.forEach(obj => {
          obj.forEach(childObj=> {
            value.checked = parentChecked;
         });
      });
    }

Use mysql_fetch_array() with foreach() instead of while()

There's not a good way to convert it to foreach, because mysql_fetch_array() just fetches the next result from $result_select. If you really wanted to foreach, you could do pull all the results into an array first, doing something like the following:

$result_list = array();
while($row = mysql_fetch_array($result_select)) {
   result_list[] = $row;
}

foreach($result_list as $row) {
   ...
}

But there's no good reason I can see to do that - and you still have to use the while loop, which is unavoidable due to how mysql_fetch_array() works. Why is it so important to use a foreach()?

EDIT: If this is just for learning purposes: you can't convert this to a foreach. You have to have a pre-existing array to use a foreach() instead of a while(), and mysql_fetch_array() fetches one result per call - there's no pre-existing array for foreach() to iterate through.

where does MySQL store database files?

another way from MySQL Workbench:

enter image description here

How to check which locks are held on a table

You can find blocking sql and wait sql by running this:

SELECT
    t1.resource_type ,
    DB_NAME( resource_database_id) AS dat_name ,
    t1.resource_associated_entity_id,
    t1.request_mode,
    t1.request_session_id,
    t2.wait_duration_ms,
    ( SELECT TEXT FROM sys.dm_exec_requests r CROSS apply sys.dm_exec_sql_text ( r.sql_handle ) WHERE r.session_id = t1.request_session_id ) AS wait_sql,
    t2.blocking_session_id,
    ( SELECT TEXT FROM sys.sysprocesses p CROSS apply sys.dm_exec_sql_text ( p.sql_handle ) WHERE p.spid = t2.blocking_session_id ) AS blocking_sql 
FROM
    sys.dm_tran_locks t1,
    sys.dm_os_waiting_tasks t2 
WHERE
    t1.lock_owner_address = t2.resource_address

Using array map to filter results with if conditional

You should use Array.prototype.reduce to do this. I did do a little JS perf test to verify that this is more performant than doing a .filter + .map.

$scope.appIds = $scope.applicationsHere.reduce(function(ids, obj){
    if(obj.selected === true){
        ids.push(obj.id);
    }
    return ids;
}, []);

Just for the sake of clarity, here's the sample .reduce I used in the JSPerf test:

_x000D_
_x000D_
  var things = [_x000D_
    {id: 1, selected: true},_x000D_
    {id: 2, selected: true},_x000D_
    {id: 3, selected: true},_x000D_
    {id: 4, selected: true},_x000D_
    {id: 5, selected: false},_x000D_
    {id: 6, selected: true},_x000D_
    {id: 7, selected: false},_x000D_
    {id: 8, selected: true},_x000D_
    {id: 9, selected: false},_x000D_
    {id: 10, selected: true},_x000D_
  ];_x000D_
  _x000D_
   _x000D_
var ids = things.reduce((ids, thing) => {_x000D_
  if (thing.selected) {_x000D_
    ids.push(thing.id);_x000D_
  }_x000D_
  return ids;_x000D_
}, []);_x000D_
_x000D_
console.log(ids)
_x000D_
_x000D_
_x000D_


EDIT 1

Note, As of 2/2018 Reduce + Push is fastest in Chrome and Edge, but slower than Filter + Map in Firefox

How can I slice an ArrayList out of an ArrayList in Java?

Although this post is very old. In case if somebody is looking for this..

Guava facilitates partitioning the List into sublists of a specified size

List<Integer> intList = Lists.newArrayList(1, 2, 3, 4, 5, 6, 7, 8);
    List<List<Integer>> subSets = Lists.partition(intList, 3);

No 'Access-Control-Allow-Origin' header is present on the requested resource error

For development you can use https://cors-anywhere.herokuapp.com , for production is better to set up your own proxy

_x000D_
_x000D_
async function read() {_x000D_
   let r= await (await fetch('https://cors-anywhere.herokuapp.com/http://ajax.googleapis.com/ajax/services/feed/load?v=1.0&num=10&q=http://feeds.feedburner.com/mathrubhumi')).json();_x000D_
   console.log(r);_x000D_
}_x000D_
_x000D_
read();
_x000D_
_x000D_
_x000D_

Confusing "duplicate identifier" Typescript error message

run the following command will fix this issue.

npm install @types/node --save-dev

Most efficient solution for reading CLOB to String, and String to CLOB in Java?

What's wrong with:

clob.getSubString(1, (int) clob.length());

?

For example Oracle oracle.sql.CLOB performs getSubString() on internal char[] which defined in oracle.jdbc.driver.T4CConnection and just System.arraycopy() and next wrap to String... You never get faster reading than System.arraycopy().

UPDATE Get driver ojdbc6.jar, decompile CLOB implementation, and study which case could be faster based on the internals knowledge.

What is the 'open' keyword in Swift?

open is a new access level in Swift 3, introduced with the implementation of

It is available with the Swift 3 snapshot from August 7, 2016, and with Xcode 8 beta 6.

In short:

  • An open class is accessible and subclassable outside of the defining module. An open class member is accessible and overridable outside of the defining module.
  • A public class is accessible but not subclassable outside of the defining module. A public class member is accessible but not overridable outside of the defining module.

So open is what public used to be in previous Swift releases and the access of public has been restricted. Or, as Chris Lattner puts it in SE-0177: Allow distinguishing between public access and public overridability:

“open” is now simply “more public than public”, providing a very simple and clean model.

In your example, open var hashValue is a property which is accessible and can be overridden in NSObject subclasses.

For more examples and details, have a look at SE-0117.

How to open select file dialog via js?

In HTML only:

<label>
  <input type="file" name="input-name" style="display: none;" />
  <span>Select file</span>
</label>

Edit: I hadn't tested this in Blink, it actually doesn't work with a <button>, but it should work with most other elements–at least in recent browsers.

Check this fiddle with the code above.

Bootstrap col-md-offset-* not working

check this bootply

this is wrong because bootstrap using margin-left:**%

.jumbotron h2:first-child {
   margin: 120px 0 0;
}

Remove specific commit

From other answers here, I was kind of confused with how git rebase -i could be used to remove a commit, so I hope it's OK to jot down my test case here (very similar to the OP).

Here is a bash script that you can paste in to create a test repository in the /tmp folder:

set -x

rm -rf /tmp/myrepo*
cd /tmp

mkdir myrepo_git
cd myrepo_git
git init
git config user.name me
git config user.email [email protected]

mkdir folder
echo aaaa >> folder/file.txt
git add folder/file.txt
git commit -m "1st git commit"

echo bbbb >> folder/file.txt
git add folder/file.txt
git commit -m "2nd git commit"

echo cccc >> folder/file.txt
git add folder/file.txt
git commit -m "3rd git commit"

echo dddd >> folder/file.txt
git add folder/file.txt
git commit -m "4th git commit"

echo eeee >> folder/file.txt
git add folder/file.txt
git commit -m "5th git commit"

At this point, we have a file.txt with these contents:

aaaa
bbbb
cccc
dddd
eeee

At this point, HEAD is at the 5th commit, HEAD~1 would be the 4th - and HEAD~4 would be the 1st commit (so HEAD~5 wouldn't exist). Let's say we want to remove the 3rd commit - we can issue this command in the myrepo_git directory:

git rebase -i HEAD~4

(Note that git rebase -i HEAD~5 results with "fatal: Needed a single revision; invalid upstream HEAD~5".) A text editor (see screenshot in @Dennis' answer) will open with these contents:

pick 5978582 2nd git commit
pick 448c212 3rd git commit
pick b50213c 4th git commit
pick a9c8fa1 5th git commit

# Rebase b916e7f..a9c8fa1 onto b916e7f
# ...

So we get all commits since (but not including) our requested HEAD~4. Delete the line pick 448c212 3rd git commit and save the file; you'll get this response from git rebase:

error: could not apply b50213c... 4th git commit

When you have resolved this problem run "git rebase --continue".
If you would prefer to skip this patch, instead run "git rebase --skip".
To check out the original branch and stop rebasing run "git rebase --abort".
Could not apply b50213c... 4th git commit

At this point open myrepo_git/folder/file.txt in a text editor; you'll see it has been modified:

aaaa
bbbb
<<<<<<< HEAD
=======
cccc
dddd
>>>>>>> b50213c... 4th git commit

Basically, git sees that when HEAD got to 2nd commit, there was content of aaaa + bbbb; and then it has a patch of added cccc+dddd which it doesn't know how to append to the existing content.

So here git cannot decide for you - it is you who has to make a decision: by removing the 3rd commit, you either keep the changes introduced by it (here, the line cccc) -- or you don't. If you don't, simply remove the extra lines - including the cccc - in folder/file.txt using a text editor, so it looks like this:

aaaa
bbbb
dddd

... and then save folder/file.txt. Now you can issue the following commands in myrepo_git directory:

$ nano folder/file.txt  # text editor - edit, save
$ git rebase --continue
folder/file.txt: needs merge
You must edit all merge conflicts and then
mark them as resolved using git add

Ah - so in order to mark that we've solved the conflict, we must git add the folder/file.txt, before doing git rebase --continue:

$ git add folder/file.txt
$ git rebase --continue

Here a text editor opens again, showing the line 4th git commit - here we have a chance to change the commit message (which in this case could be meaningfully changed to 4th (and removed 3rd) commit or similar). Let's say you don't want to - so just exit the text editor without saving; once you do that, you'll get:

$ git rebase --continue
[detached HEAD b8275fc] 4th git commit
 1 file changed, 1 insertion(+)
Successfully rebased and updated refs/heads/master.

At this point, now you have a history like this (which you could also inspect with say gitk . or other tools) of the contents of folder/file.txt (with, apparently, unchanged timestamps of the original commits):

1st git commit  |  +aaaa
----------------------------------------------
2nd git commit  |   aaaa
                |  +bbbb
----------------------------------------------
4th git commit  |   aaaa
                |   bbbb
                |  +dddd
----------------------------------------------
5th git commit  |   aaaa
                |   bbbb
                |   dddd
                |  +eeee

And if previously, we decided to keep the line cccc (the contents of the 3rd git commit that we removed), we would have had:

1st git commit  |  +aaaa
----------------------------------------------
2nd git commit  |   aaaa
                |  +bbbb
----------------------------------------------
4th git commit  |   aaaa
                |   bbbb
                |  +cccc
                |  +dddd
----------------------------------------------
5th git commit  |   aaaa
                |   bbbb
                |   cccc
                |   dddd
                |  +eeee

Well, this was the kind of reading I hoped I'd have found, to start grokking how git rebase works in terms of deleting commits/revisions; so hope it might help others too...

What is the strict aliasing rule?

Note

This is excerpted from my "What is the Strict Aliasing Rule and Why do we care?" write-up.

What is strict aliasing?

In C and C++ aliasing has to do with what expression types we are allowed to access stored values through. In both C and C++ the standard specifies which expression types are allowed to alias which types. The compiler and optimizer are allowed to assume we follow the aliasing rules strictly, hence the term strict aliasing rule. If we attempt to access a value using a type not allowed it is classified as undefined behavior(UB). Once we have undefined behavior all bets are off, the results of our program are no longer reliable.

Unfortunately with strict aliasing violations, we will often obtain the results we expect, leaving the possibility the a future version of a compiler with a new optimization will break code we thought was valid. This is undesirable and it is a worthwhile goal to understand the strict aliasing rules and how to avoid violating them.

To understand more about why we care, we will discuss issues that come up when violating strict aliasing rules, type punning since common techniques used in type punning often violate strict aliasing rules and how to type pun correctly.

Preliminary examples

Let's look at some examples, then we can talk about exactly what the standard(s) say, examine some further examples and then see how to avoid strict aliasing and catch violations we missed. Here is an example that should not be surprising (live example):

int x = 10;
int *ip = &x;

std::cout << *ip << "\n";
*ip = 12;
std::cout << x << "\n";

We have a int* pointing to memory occupied by an int and this is a valid aliasing. The optimizer must assume that assignments through ip could update the value occupied by x.

The next example shows aliasing that leads to undefined behavior (live example):

int foo( float *f, int *i ) { 
    *i = 1;               
    *f = 0.f;            

   return *i;
}

int main() {
    int x = 0;

    std::cout << x << "\n";   // Expect 0
    x = foo(reinterpret_cast<float*>(&x), &x);
    std::cout << x << "\n";   // Expect 0?
}

In the function foo we take an int* and a float*, in this example we call foo and set both parameters to point to the same memory location which in this example contains an int. Note, the reinterpret_cast is telling the compiler to treat the the expression as if it had the type specificed by its template parameter. In this case we are telling it to treat the expression &x as if it had type float*. We may naively expect the result of the second cout to be 0 but with optimization enabled using -O2 both gcc and clang produce the following result:

0
1

Which may not be expected but is perfectly valid since we have invoked undefined behavior. A float can not validly alias an int object. Therefore the optimizer can assume the constant 1 stored when dereferencing i will be the return value since a store through f could not validly affect an int object. Plugging the code in Compiler Explorer shows this is exactly what is happening(live example):

foo(float*, int*): # @foo(float*, int*)
mov dword ptr [rsi], 1  
mov dword ptr [rdi], 0
mov eax, 1                       
ret

The optimizer using Type-Based Alias Analysis (TBAA) assumes 1 will be returned and directly moves the constant value into register eax which carries the return value. TBAA uses the languages rules about what types are allowed to alias to optimize loads and stores. In this case TBAA knows that a float can not alias and int and optimizes away the load of i.

Now, to the Rule-Book

What exactly does the standard say we are allowed and not allowed to do? The standard language is not straightforward, so for each item I will try to provide code examples that demonstrates the meaning.

What does the C11 standard say?

The C11 standard says the following in section 6.5 Expressions paragraph 7:

An object shall have its stored value accessed only by an lvalue expression that has one of the following types:88) — a type compatible with the effective type of the object,

int x = 1;
int *p = &x;   
printf("%d\n", *p); // *p gives us an lvalue expression of type int which is compatible with int

— a qualified version of a type compatible with the effective type of the object,

int x = 1;
const int *p = &x;
printf("%d\n", *p); // *p gives us an lvalue expression of type const int which is compatible with int

— a type that is the signed or unsigned type corresponding to the effective type of the object,

int x = 1;
unsigned int *p = (unsigned int*)&x;
printf("%u\n", *p ); // *p gives us an lvalue expression of type unsigned int which corresponds to 
                     // the effective type of the object

gcc/clang has an extension and also that allows assigning unsigned int* to int* even though they are not compatible types.

— a type that is the signed or unsigned type corresponding to a qualified version of the effective type of the object,

int x = 1;
const unsigned int *p = (const unsigned int*)&x;
printf("%u\n", *p ); // *p gives us an lvalue expression of type const unsigned int which is a unsigned type 
                     // that corresponds with to a qualified verison of the effective type of the object

— an aggregate or union type that includes one of the aforementioned types among its members (including, recursively, a member of a subaggregate or contained union), or

struct foo {
  int x;
};

void foobar( struct foo *fp, int *ip );  // struct foo is an aggregate that includes int among its members so it can
                                         // can alias with *ip

foo f;
foobar( &f, &f.x );

— a character type.

int x = 65;
char *p = (char *)&x;
printf("%c\n", *p );  // *p gives us an lvalue expression of type char which is a character type.
                      // The results are not portable due to endianness issues.

What the C++17 Draft Standard say

The C++17 draft standard in section [basic.lval] paragraph 11 says:

If a program attempts to access the stored value of an object through a glvalue of other than one of the following types the behavior is undefined:63 (11.1) — the dynamic type of the object,

void *p = malloc( sizeof(int) ); // We have allocated storage but not started the lifetime of an object
int *ip = new (p) int{0};        // Placement new changes the dynamic type of the object to int
std::cout << *ip << "\n";        // *ip gives us a glvalue expression of type int which matches the dynamic type 
                                  // of the allocated object

(11.2) — a cv-qualified version of the dynamic type of the object,

int x = 1;
const int *cip = &x;
std::cout << *cip << "\n";  // *cip gives us a glvalue expression of type const int which is a cv-qualified 
                            // version of the dynamic type of x

(11.3) — a type similar (as defined in 7.5) to the dynamic type of the object,

(11.4) — a type that is the signed or unsigned type corresponding to the dynamic type of the object,

// Both si and ui are signed or unsigned types corresponding to each others dynamic types
// We can see from this godbolt(https://godbolt.org/g/KowGXB) the optimizer assumes aliasing.
signed int foo( signed int &si, unsigned int &ui ) {
  si = 1;
  ui = 2;

  return si;
}

(11.5) — a type that is the signed or unsigned type corresponding to a cv-qualified version of the dynamic type of the object,

signed int foo( const signed int &si1, int &si2); // Hard to show this one assumes aliasing

(11.6) — an aggregate or union type that includes one of the aforementioned types among its elements or nonstatic data members (including, recursively, an element or non-static data member of a subaggregate or contained union),

struct foo {
 int x;
};

// Compiler Explorer example(https://godbolt.org/g/z2wJTC) shows aliasing assumption
int foobar( foo &fp, int &ip ) {
 fp.x = 1;
 ip = 2;

 return fp.x;
}

foo f; 
foobar( f, f.x ); 

(11.7) — a type that is a (possibly cv-qualified) base class type of the dynamic type of the object,

struct foo { int x ; };

struct bar : public foo {};

int foobar( foo &f, bar &b ) {
  f.x = 1;
  b.x = 2;

  return f.x;
}

(11.8) — a char, unsigned char, or std::byte type.

int foo( std::byte &b, uint32_t &ui ) {
  b = static_cast<std::byte>('a');
  ui = 0xFFFFFFFF;                   

  return std::to_integer<int>( b );  // b gives us a glvalue expression of type std::byte which can alias
                                     // an object of type uint32_t
}

Worth noting signed char is not included in the list above, this is a notable difference from C which says a character type.

What is Type Punning

We have gotten to this point and we may be wondering, why would we want to alias for? The answer typically is to type pun, often the methods used violate strict aliasing rules.

Sometimes we want to circumvent the type system and interpret an object as a different type. This is called type punning, to reinterpret a segment of memory as another type. Type punning is useful for tasks that want access to the underlying representation of an object to view, transport or manipulate. Typical areas we find type punning being used are compilers, serialization, networking code, etc…

Traditionally this has been accomplished by taking the address of the object, casting it to a pointer of the type we want to reinterpret it as and then accessing the value, or in other words by aliasing. For example:

int x =  1 ;

// In C
float *fp = (float*)&x ;  // Not a valid aliasing

// In C++
float *fp = reinterpret_cast<float*>(&x) ;  // Not a valid aliasing

printf( "%f\n", *fp ) ;

As we have seen earlier this is not a valid aliasing, so we are invoking undefined behavior. But traditionally compilers did not take advantage of strict aliasing rules and this type of code usually just worked, developers have unfortunately gotten used to doing things this way. A common alternate method for type punning is through unions, which is valid in C but undefined behavior in C++ (see live example):

union u1
{
  int n;
  float f;
} ;

union u1 u;
u.f = 1.0f;

printf( "%d\n”, u.n );  // UB in C++ n is not the active member

This is not valid in C++ and some consider the purpose of unions to be solely for implementing variant types and feel using unions for type punning is an abuse.

How do we Type Pun correctly?

The standard method for type punning in both C and C++ is memcpy. This may seem a little heavy handed but the optimizer should recognize the use of memcpy for type punning and optimize it away and generate a register to register move. For example if we know int64_t is the same size as double:

static_assert( sizeof( double ) == sizeof( int64_t ) );  // C++17 does not require a message

we can use memcpy:

void func1( double d ) {
  std::int64_t n;
  std::memcpy(&n, &d, sizeof d); 
  //...

At a sufficient optimization level any decent modern compiler generates identical code to the previously mentioned reinterpret_cast method or union method for type punning. Examining the generated code we see it uses just register mov (live Compiler Explorer Example).

C++20 and bit_cast

In C++20 we may gain bit_cast (implementation available in link from proposal) which gives a simple and safe way to type-pun as well as being usable in a constexpr context.

The following is an example of how to use bit_cast to type pun a unsigned int to float, (see it live):

std::cout << bit_cast<float>(0x447a0000) << "\n" ; //assuming sizeof(float) == sizeof(unsigned int)

In the case where To and From types don't have the same size, it requires us to use an intermediate struct15. We will use a struct containing a sizeof( unsigned int ) character array (assumes 4 byte unsigned int) to be the From type and unsigned int as the To type.:

struct uint_chars {
 unsigned char arr[sizeof( unsigned int )] = {} ;  // Assume sizeof( unsigned int ) == 4
};

// Assume len is a multiple of 4 
int bar( unsigned char *p, size_t len ) {
 int result = 0;

 for( size_t index = 0; index < len; index += sizeof(unsigned int) ) {
   uint_chars f;
   std::memcpy( f.arr, &p[index], sizeof(unsigned int));
   unsigned int result = bit_cast<unsigned int>(f);

   result += foo( result );
 }

 return result ;
}

It is unfortunate that we need this intermediate type but that is the current constraint of bit_cast.

Catching Strict Aliasing Violations

We don't have a lot of good tools for catching strict aliasing in C++, the tools we have will catch some cases of strict aliasing violations and some cases of misaligned loads and stores.

gcc using the flag -fstrict-aliasing and -Wstrict-aliasing can catch some cases although not without false positives/negatives. For example the following cases will generate a warning in gcc (see it live):

int a = 1;
short j;
float f = 1.f; // Originally not initialized but tis-kernel caught 
               // it was being accessed w/ an indeterminate value below

printf("%i\n", j = *(reinterpret_cast<short*>(&a)));
printf("%i\n", j = *(reinterpret_cast<int*>(&f)));

although it will not catch this additional case (see it live):

int *p;

p=&a;
printf("%i\n", j = *(reinterpret_cast<short*>(p)));

Although clang allows these flags it apparently does not actually implement the warnings.

Another tool we have available to us is ASan which can catch misaligned loads and stores. Although these are not directly strict aliasing violations they are a common result of strict aliasing violations. For example the following cases will generate runtime errors when built with clang using -fsanitize=address

int *x = new int[2];               // 8 bytes: [0,7].
int *u = (int*)((char*)x + 6);     // regardless of alignment of x this will not be an aligned address
*u = 1;                            // Access to range [6-9]
printf( "%d\n", *u );              // Access to range [6-9]

The last tool I will recommend is C++ specific and not strictly a tool but a coding practice, don't allow C-style casts. Both gcc and clang will produce a diagnostic for C-style casts using -Wold-style-cast. This will force any undefined type puns to use reinterpret_cast, in general reinterpret_cast should be a flag for closer code review. It is also easier to search your code base for reinterpret_cast to perform an audit.

For C we have all the tools already covered and we also have tis-interpreter, a static analyzer that exhaustively analyzes a program for a large subset of the C language. Given a C verions of the earlier example where using -fstrict-aliasing misses one case (see it live)

int a = 1;
short j;
float f = 1.0 ;

printf("%i\n", j = *((short*)&a));
printf("%i\n", j = *((int*)&f));

int *p; 

p=&a;
printf("%i\n", j = *((short*)p));

tis-interpeter is able to catch all three, the following example invokes tis-kernal as tis-interpreter (output is edited for brevity):

./bin/tis-kernel -sa example1.c 
...
example1.c:9:[sa] warning: The pointer (short *)(& a) has type short *. It violates strict aliasing
              rules by accessing a cell with effective type int.
...

example1.c:10:[sa] warning: The pointer (int *)(& f) has type int *. It violates strict aliasing rules by
              accessing a cell with effective type float.
              Callstack: main
...

example1.c:15:[sa] warning: The pointer (short *)p has type short *. It violates strict aliasing rules by
              accessing a cell with effective type int.

Finally there is TySan which is currently in development. This sanitizer adds type checking information in a shadow memory segment and checks accesses to see if they violate aliasing rules. The tool potentially should be able to catch all aliasing violations but may have a large run-time overhead.

Difference between request.getSession() and request.getSession(true)

request.getSession() is just a convenience method. It does exactly the same as request.getSession(true).

Iterate over object in Angular

If someone is wondering how to work with multidimensional object, here is the solution.

lets assume we have following object in service

getChallenges() {
    var objects = {};
    objects['0'] = { 
        title: 'Angular2', 
        description : "Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur."
    };

    objects['1'] = { 
        title: 'AngularJS', 
        description : "Lorem Ipsum is simply dummy text of the printing and typesetting industry."
    };

    objects['2'] = { 
        title: 'Bootstrap',
        description : "Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.",
    };
    return objects;
}

in component add following function

challenges;

constructor(testService : TestService){
    this.challenges = testService.getChallenges();
}
keys() : Array<string> {
    return Object.keys(this.challenges);
}

finally in view do following

<div *ngFor="#key of keys();">
    <h4 class="heading">{{challenges[key].title}}</h4>
    <p class="description">{{challenges[key].description}}</p>
</div>

How can I replace non-printable Unicode characters in Java?

You may be interested in the Unicode categories "Other, Control" and possibly "Other, Format" (unfortunately the latter seems to contain both unprintable and printable characters).

In Java regular expressions you can check for them using \p{Cc} and \p{Cf} respectively.

What is the equivalent to getLastInsertId() in Cakephp?

Below are the options:

echo $this->Registration->id;

echo $this->Registration->getInsertID();

echo $this->Registration->getLastInsertId();

Here, you can replace Registration with your model name.

Thanks

How to convert Varchar to Double in sql?

use DECIMAL() or NUMERIC() as they are fixed precision and scale numbers.

SELECT fullName, 
       CAST(totalBal as DECIMAL(9,2)) _totalBal
FROM client_info 
ORDER BY _totalBal DESC

What are intent-filters in Android?

Keep the first intent filter with keys MAIN and LAUNCHER and add another as ANY_NAME and DEFAULT.

Your LAUNCHER will be activity A and DEFAULT will be your activity B.

How to iterate through a table rows and get the cell values using jQuery

Hello every one thanks for the help below is the working code for my question

$("#TableView tr.item").each(function() { 
    var quantity1=$(this).find("input.name").val(); 
    var quantity2=$(this).find("input.id").val(); 
});

How to change the datetime format in pandas

The below code worked for me instead of the previous one - try it out !

df['DOB']=pd.to_datetime(df['DOB'].astype(str), format='%m/%d/%Y')

How do I connect to mongodb with node.js (and authenticate)?

Per the source:

After connecting:

Db.authenticate(user, password, function(err, res) {
  // callback
});

C++ string to double conversion

The problem is that C++ is a statically-typed language, meaning that if something is declared as a string, it's a string, and if something is declared as a double, it's a double. Unlike other languages like JavaScript or PHP, there is no way to automatically convert from a string to a numeric value because the conversion might not be well-defined. For example, if you try converting the string "Hi there!" to a double, there's no meaningful conversion. Sure, you could just set the double to 0.0 or NaN, but this would almost certainly be masking the fact that there's a problem in the code.

To fix this, don't buffer the file contents into a string. Instead, just read directly into the double:

double lol;
openfile >> lol;

This reads the value directly as a real number, and if an error occurs will cause the stream's .fail() method to return true. For example:

double lol;
openfile >> lol;

if (openfile.fail()) {
    cout << "Couldn't read a double from the file." << endl;
}

How do you extract a column from a multi-dimensional array?

Well a 'bit' late ...

In case performance matters and your data is shaped rectangular, you might also store it in one dimension and access the columns by regular slicing e.g. ...

A = [[1,2,3,4],[5,6,7,8]]     #< assume this 4x2-matrix
B = reduce( operator.add, A ) #< get it one-dimensional

def column1d( matrix, dimX, colIdx ):
  return matrix[colIdx::dimX]

def row1d( matrix, dimX, rowIdx ):
  return matrix[rowIdx:rowIdx+dimX] 

>>> column1d( B, 4, 1 )
[2, 6]
>>> row1d( B, 4, 1 )
[2, 3, 4, 5]

The neat thing is this is really fast. However, negative indexes don't work here! So you can't access the last column or row by index -1.

If you need negative indexing you can tune the accessor-functions a bit, e.g.

def column1d( matrix, dimX, colIdx ):
  return matrix[colIdx % dimX::dimX]

def row1d( matrix, dimX, dimY, rowIdx ):
  rowIdx = (rowIdx % dimY) * dimX
  return matrix[rowIdx:rowIdx+dimX]

inner join in linq to entities

You can find a whole bunch of Linq examples in visual studio. Just select Help -> Samples, and then unzip the Linq samples.

Open the linq samples solution and open the LinqSamples.cs of the SampleQueries project.

The answer you are looking for is in method Linq14:

int[] numbersA = { 0, 2, 4, 5, 6, 8, 9 };
int[] numbersB = { 1, 3, 5, 7, 8 };

var pairs =
   from a in numbersA
   from b in numbersB
   where a < b
   select new {a, b};

How to preSelect an html dropdown list with php?

you can use this..

<select name="select_name">
    <option value="1"<?php echo(isset($_POST['select_name'])&&($_POST['select_name']=='1')?' selected="selected"':'');?>>Yes</option>
    <option value="2"<?php echo(isset($_POST['select_name'])&&($_POST['select_name']=='2')?' selected="selected"':'');?>>No</option>
    <option value="3"<?php echo(isset($_POST['select_name'])&&($_POST['select_name']=='3')?' selected="selected"':'');?>>Fine</option>
</select>

Read .csv file in C

Thought I'd share this code. It's fairly simple, but effective. It parses comma-separated files with parenthesis. You can easily modify it to suit your needs.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>


int main(int argc, char *argv[])
{
  //argv[1] path to csv file
  //argv[2] number of lines to skip
  //argv[3] length of longest value (in characters)

  FILE *pfinput;
  unsigned int nSkipLines, currentLine, lenLongestValue;
  char *pTempValHolder;
  int c;
  unsigned int vcpm; //value character marker
  int QuotationOnOff; //0 - off, 1 - on

  nSkipLines = atoi(argv[2]);
  lenLongestValue = atoi(argv[3]);

  pTempValHolder = (char*)malloc(lenLongestValue);  

  if( pfinput = fopen(argv[1],"r") ) {

    rewind(pfinput);

    currentLine = 1;
    vcpm = 0;
    QuotationOnOff = 0;

    //currentLine > nSkipLines condition skips ignores first argv[2] lines
    while( (c = fgetc(pfinput)) != EOF)
    {
       switch(c)
       {
          case ',':
            if(!QuotationOnOff && currentLine > nSkipLines) 
            {
              pTempValHolder[vcpm] = '\0';
              printf("%s,",pTempValHolder);
              vcpm = 0;
            }
            break;
          case '\n':
            if(currentLine > nSkipLines)
            {
              pTempValHolder[vcpm] = '\0';
              printf("%s\n",pTempValHolder);
              vcpm = 0;
            }
            currentLine++;
            break;
          case '\"':
            if(currentLine > nSkipLines)
            {
              if(!QuotationOnOff) {
                QuotationOnOff = 1;
                pTempValHolder[vcpm] = c;
                vcpm++;
              } else {
                QuotationOnOff = 0;
                pTempValHolder[vcpm] = c;
                vcpm++;
              }
            }
            break;
          default:
            if(currentLine > nSkipLines)
            {
              pTempValHolder[vcpm] = c;
              vcpm++;
            }
            break;
       }
    }

    fclose(pfinput); 
    free(pTempValHolder);

  }

  return 0;
}

Setting timezone to UTC (0) in PHP

Is 'UTC' a valid timezone identifier on your system?

<?php
if (date_default_timezone_set('UTC')){
    echo "UTC is a valid time zone";
}else{
    echo "The system doesn't know WTFUTC.  Maybe try updating tzinfo with your package manager?";
}

How do I get the number of elements in a list?

There is an inbuilt function called len() in python which will help in these conditions.

a=[1,2,3,4,5,6]
print(len(a))     #Here the len() function counts the number of items in the list.

Output:

>>> 6

This will work slightly different in the case of string (below):

a="Hello"
print(len(a)) #Here the len() function counts the alphabets or characters in the list.

Output:

>>> 5

This is because variable (a) is a string and not a list, so it will count the number of characters or alphabets in the string and then print the output.

Recursively list all files in a directory including files in symlink directories

ls -R -L

-L dereferences symbolic links. This will also make it impossible to see any symlinks to files, though - they'll look like the pointed-to file.

Stopping Excel Macro executution when pressing Esc won't work

My laptop did not have Break nor Scr Lock, so I somehow managed to make it work by pressing Ctrl + Function + Right Shift (to activate 'pause').

How to do a for loop in windows command line?

This may help you find what you're looking for... Batch script loop

My answer is as follows:

@echo off
:start
set /a var+=1
if %var% EQU 100 goto end
:: Code you want to run goes here
goto start

:end
echo var has reached %var%.
pause
exit

The first set of commands under the start label loops until a variable, %var% reaches 100. Once this happens it will notify you and allow you to exit. This code can be adapted to your needs by changing the 100 to 17 and putting your code or using a call command followed by the batch file's path (Shift+Right Click on file and select "Copy as Path") where the comment is placed.

How to add onload event to a div element

use an iframe and hide it iframe works like a body tag

<!DOCTYPE html>
<html>
<body>

<iframe style="display:none" onload="myFunction()" src="http://www.w3schools.com"></iframe>
<p id="demo"></p>

<script>
function myFunction() {
    document.getElementById("demo").innerHTML = "Iframe is loaded.";
}
</script>

</body>
</html>

How do you display a Toast from a background thread on Android?

  1. Get UI Thread Handler instance and use handler.sendMessage();
  2. Call post() method handler.post();
  3. runOnUiThread()
  4. view.post()

Windows 10 SSH keys

I'm running Microsoft Windows 10 Pro, Version 10.0.17763 Build 17763, and I see my .ssh folder easily at C:\Users\jrosario\.ssh without having to edit permissions or anything (though in File Explorer, I did select "Show hidden files, folders and drives"): enter image description here

The keys are stored in a text file named known_hosts, which looks roughly like this: enter image description here

Retrieving a List from a java.util.stream.Stream in Java 8

Here is code by AbacusUtil

LongStream.of(1, 10, 50, 80, 100, 120, 133, 333).filter(e -> e > 100).toList();

Disclosure: I'm the developer of AbacusUtil.

Best way to detect Mac OS X or Windows computers with JavaScript or jQuery

Is this what you are looking for? Otherwise, let me know and I will remove this post.

Try this jQuery plugin: http://archive.plugins.jquery.com/project/client-detect

Demo: http://www.stoimen.com/jquery.client.plugin/

This is based on quirksmode BrowserDetect a wrap for jQuery browser/os detection plugin.

For keen readers:
http://www.stoimen.com/blog/2009/07/16/jquery-browser-and-os-detection-plugin/
http://www.quirksmode.org/js/support.html

And more code around the plugin resides here: http://www.stoimen.com/jquery.client.plugin/jquery.client.js

Python: Tuples/dictionaries as keys, select, sort

Personally, one of the things I love about python is the tuple-dict combination. What you have here is effectively a 2d array (where x = fruit name and y = color), and I am generally a supporter of the dict of tuples for implementing 2d arrays, at least when something like numpy or a database isn't more appropriate. So in short, I think you've got a good approach.

Note that you can't use dicts as keys in a dict without doing some extra work, so that's not a very good solution.

That said, you should also consider namedtuple(). That way you could do this:

>>> from collections import namedtuple
>>> Fruit = namedtuple("Fruit", ["name", "color"])
>>> f = Fruit(name="banana", color="red")
>>> print f
Fruit(name='banana', color='red')
>>> f.name
'banana'
>>> f.color
'red'

Now you can use your fruitcount dict:

>>> fruitcount = {Fruit("banana", "red"):5}
>>> fruitcount[f]
5

Other tricks:

>>> fruits = fruitcount.keys()
>>> fruits.sort()
>>> print fruits
[Fruit(name='apple', color='green'), 
 Fruit(name='apple', color='red'), 
 Fruit(name='banana', color='blue'), 
 Fruit(name='strawberry', color='blue')]
>>> fruits.sort(key=lambda x:x.color)
>>> print fruits
[Fruit(name='banana', color='blue'), 
 Fruit(name='strawberry', color='blue'), 
 Fruit(name='apple', color='green'), 
 Fruit(name='apple', color='red')]

Echoing chmullig, to get a list of all colors of one fruit, you would have to filter the keys, i.e.

bananas = [fruit for fruit in fruits if fruit.name=='banana']

How can I find matching values in two arrays?

Naturally, my approach was to loop through the first array once and check the index of each value in the second array. If the index is > -1, then push it onto the returned array.

?Array.prototype.diff = function(arr2) {
    var ret = [];
    for(var i in this) {   
        if(arr2.indexOf(this[i]) > -1){
            ret.push(this[i]);
        }
    }
    return ret;
};

? My solution doesn't use two loops like others do so it may run a bit faster. If you want to avoid using for..in, you can sort both arrays first to reindex all their values:

Array.prototype.diff = function(arr2) {
    var ret = [];
    this.sort();
    arr2.sort();
    for(var i = 0; i < this.length; i += 1) {
        if(arr2.indexOf(this[i]) > -1){
            ret.push(this[i]);
        }
    }
    return ret;
};

Usage would look like:

var array1 = ["cat", "sum","fun", "run", "hut"];
var array2 = ["bat", "cat","dog","sun", "hut", "gut"];

console.log(array1.diff(array2));

If you have an issue/problem with extending the Array prototype, you could easily change this to a function.

var diff = function(arr, arr2) {

And you'd change anywhere where the func originally said this to arr2.

PHP: Split string into array, like explode with no delimiter

$array = str_split("0123456789bcdfghjkmnpqrstvwxyz");

str_split takes an optional 2nd param, the chunk length (default 1), so you can do things like:

$array = str_split("aabbccdd", 2);

// $array[0] = aa
// $array[1] = bb
// $array[2] = cc  etc ...

You can also get at parts of your string by treating it as an array:

$string = "hello";
echo $string[1];

// outputs "e"

Removing duplicates from a list of lists

List of tuple and {} can be used to remove duplicates

>>> [list(tupl) for tupl in {tuple(item) for item in k }]
[[1, 2], [5, 6, 2], [3], [4]]
>>> 

Why doesn't Console.Writeline, Console.Write work in Visual Studio Express?

Right click on the project in solution-explorer and click "clean".

Now run F5

Make sure the code is as below:

Console.WriteLine("TEST");
Console.ReadLine();

jQuery - Detect value change on hidden input field

You can simply use the below function, You can also change the type element.

 $("input[type=hidden]").bind("change", function() {
       alert($(this).val()); 
 });

Changes in value to hidden elements don't automatically fire the .change() event. So, wherever it is that you're setting that value, you also have to tell jQuery to trigger it.

HTML

 <div id="message"></div>
<input type="hidden" id="testChange" value="0"  />    

JAVASCRIPT

var $message = $('#message');
var $testChange = $('#testChange');
var i = 1;

function updateChange() {
    $message.html($message.html() + '<p>Changed to ' + $testChange.val() + '</p>');
}

$testChange.on('change', updateChange);

setInterval(function() {
    $testChange.val(++i).trigger('change');; 
    console.log("value changed" +$testChange.val());
}, 3000);

updateChange();

should work as expected.

http://jsfiddle.net/7CM6k/3/

IOError: [Errno 2] No such file or directory trying to open a file

I got this error and fixed by appending the directory path in the loop. script not in the same directory as the files. dr1 ="~/test" directory variable

 fileop=open(dr1+"/"+fil,"r")

How do I add a delay in a JavaScript loop?

Since ES7 theres a better way to await a loop:

// Returns a Promise that resolves after "ms" Milliseconds
const timer = ms => new Promise(res => setTimeout(res, ms))

async function load () { // We need to wrap the loop into an async function for this to work
  for (var i = 0; i < 3; i++) {
    console.log(i);
    await timer(3000); // then the created Promise can be awaited
  }
}

load();

When the engine reaches the await part, it sets a timeout and halts the execution of the async function. Then when the timeout completes, execution continues at that point. That's quite useful as you can delay (1) nested loops, (2) conditionally, (3) nested functions:

_x000D_
_x000D_
async function task(i) { // 3
  await timer(1000);
  console.log(`Task ${i} done!`);
}

async function main() {
  for(let i = 0; i < 100; i+= 10) {
    for(let j = 0; j < 10; j++) { // 1
      if(j % 2) { // 2
        await task(i + j);
      }
    }
  }
}
    
main();

function timer(ms) { return new Promise(res => setTimeout(res, ms)); }
_x000D_
_x000D_
_x000D_

Reference on MDN

While ES7 is now supported by NodeJS and modern browsers, you might want to transpile it with BabelJS so that it runs everywhere.

You don't have write permissions for the /var/lib/gems/2.3.0 directory

If you want to use the distribution Ruby instead of rb-env/rvm, you can set up a GEM_HOME for your current user. Start by creating a directory to store the Ruby gems for your user:

$ mkdir ~/.ruby

Then update your shell to use that directory for GEM_HOME and to update your PATH variable to include the Ruby gem bin directory.

$ echo 'export GEM_HOME=~/.ruby/' >> ~/.bashrc
$ echo 'export PATH="$PATH:~/.ruby/bin"' >> ~/.bashrc
$ source ~/.bashrc

(That last line will reload the environment variables in your current shell.)

Now you should be able to install Ruby gems under your user using the gem command. I was able to get this working with Ruby 2.5.1 under Ubuntu 18.04. If you are using a shell that is not Bash, then you will need to edit the startup script for that shell instead of bashrc.

How to find out if you're using HTTPS without $_SERVER['HTTPS']

If You use nginx as loadbalancing system check $_SERVER['HTTP_HTTPS'] == 1 other checks will be fail for ssl.

Find files and tar them (with spaces)

Use this:

find . -type f -print0 | tar -czvf backup.tar.gz --null -T -

It will:

  • deal with files with spaces, newlines, leading dashes, and other funniness
  • handle an unlimited number of files
  • won't repeatedly overwrite your backup.tar.gz like using tar -c with xargs will do when you have a large number of files

Also see:

How to measure time elapsed on Javascript?

The Date documentation states that :

The JavaScript date is based on a time value that is milliseconds since midnight January 1, 1970, UTC

Click on start button then on end button. It will show you the number of seconds between the 2 clicks.

The milliseconds diff is in variable timeDiff. Play with it to find seconds/minutes/hours/ or what you need

_x000D_
_x000D_
var startTime, endTime;_x000D_
_x000D_
function start() {_x000D_
  startTime = new Date();_x000D_
};_x000D_
_x000D_
function end() {_x000D_
  endTime = new Date();_x000D_
  var timeDiff = endTime - startTime; //in ms_x000D_
  // strip the ms_x000D_
  timeDiff /= 1000;_x000D_
_x000D_
  // get seconds _x000D_
  var seconds = Math.round(timeDiff);_x000D_
  console.log(seconds + " seconds");_x000D_
}
_x000D_
<button onclick="start()">Start</button>_x000D_
_x000D_
<button onclick="end()">End</button>
_x000D_
_x000D_
_x000D_

OR another way of doing it for modern browser

Using performance.now() which returns a value representing the time elapsed since the time origin. This value is a double with microseconds in the fractional.

The time origin is a standard time which is considered to be the beginning of the current document's lifetime.

_x000D_
_x000D_
var startTime, endTime;_x000D_
_x000D_
function start() {_x000D_
  startTime = performance.now();_x000D_
};_x000D_
_x000D_
function end() {_x000D_
  endTime = performance.now();_x000D_
  var timeDiff = endTime - startTime; //in ms _x000D_
  // strip the ms _x000D_
  timeDiff /= 1000; _x000D_
  _x000D_
  // get seconds _x000D_
  var seconds = Math.round(timeDiff);_x000D_
  console.log(seconds + " seconds");_x000D_
}
_x000D_
<button onclick="start()">Start</button>_x000D_
<button onclick="end()">End</button>
_x000D_
_x000D_
_x000D_

Does dispatch_async(dispatch_get_main_queue(), ^{...}); wait until done?

If you want to run a single independent queued operation and you’re not concerned with other concurrent operations, you can use the global concurrent queue:

dispatch_queue_t globalConcurrentQueue =
dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)

This will return a concurrent queue with the given priority as outlined in the documentation:

DISPATCH_QUEUE_PRIORITY_HIGH Items dispatched to the queue will run at high priority, i.e. the queue will be scheduled for execution before any default priority or low priority queue.

DISPATCH_QUEUE_PRIORITY_DEFAULT Items dispatched to the queue will run at the default priority, i.e. the queue will be scheduled for execution after all high priority queues have been scheduled, but before any low priority queues have been scheduled.

DISPATCH_QUEUE_PRIORITY_LOW Items dispatched to the queue will run at low priority, i.e. the queue will be scheduled for execution after all default priority and high priority queues have been scheduled.

DISPATCH_QUEUE_PRIORITY_BACKGROUND Items dispatched to the queue will run at background priority, i.e. the queue will be scheduled for execution after all higher priority queues have been scheduled and the system will run items on this queue on a thread with background status as per setpriority(2) (i.e. disk I/O is throttled and the thread’s scheduling priority is set to lowest value).

Clear an input field with Reactjs?

On the event of onClick

this.state={
  title:''
}

sendthru=()=>{
  document.getElementByid('inputname').value = '';
  this.setState({
     title:''
})
}
<input type="text" id="inputname" className="form-control" ref={el => this.inputTitle = el} />   
<button className="btn btn-info" onClick={this.sendthru}>Add</button>

How do I specify the JDK for a GlassFish domain?

Had the same problem in my IntelliJ 17 after adding fresh glassfish 4.1.

I had set my JAVA_HOME environment variable as follow:

echo %JAVA_HOME%
C:\Java\jdk1.8.0_121\

Then opened %GLASSFISH_HOME%\glassfish\config\asenv.bat

And just added and the end of the file:

set AS_JAVA=%JAVA_HOME%

Then Glassfish started without problems.

PHP - get base64 img string decode and save as jpg (resulting empty image )

Decode and save image as PNG

header('content-type: image/png');

           ob_start();

        $ret = fopen($fullurl, 'r', true, $context);
        $contents = stream_get_contents($ret);
        $base64 = 'data:image/PNG;base64,' . base64_encode($contents);
        echo "<img src=$base64 />" ;


        ob_end_flush();

How to display an image from a path in asp.net MVC 4 and Razor view?

 @foreach (var m in Model)
    {
      <img src="~/Images/@m.Url" style="overflow: hidden; position: relative; width:200px; height:200px;" />
    }

Get index of element as child relative to parent

There's no need to require a big library like jQuery to accomplish this, if you don't want to. To achieve this with built-in DOM manipulation, get a collection of the li siblings in an array, and on click, check the indexOf the clicked element in that array.

_x000D_
_x000D_
const lis = [...document.querySelectorAll('#wizard > li')];_x000D_
lis.forEach((li) => {_x000D_
  li.addEventListener('click', () => {_x000D_
    const index = lis.indexOf(li);_x000D_
    console.log(index);_x000D_
  });_x000D_
});
_x000D_
<ul id="wizard">_x000D_
    <li>Step 1</li>_x000D_
    <li>Step 2</li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

Or, with event delegation:

_x000D_
_x000D_
const lis = [...document.querySelectorAll('#wizard li')];_x000D_
document.querySelector('#wizard').addEventListener('click', ({ target }) => {_x000D_
  // Make sure the clicked element is a <li> which is a child of wizard:_x000D_
  if (!target.matches('#wizard > li')) return;_x000D_
  _x000D_
  const index = lis.indexOf(target);_x000D_
  console.log(index);_x000D_
});
_x000D_
<ul id="wizard">_x000D_
    <li>Step 1</li>_x000D_
    <li>Step 2</li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

Or, if the child elements may change dynamically (like with a todo list), then you'll have to construct the array of lis on every click, rather than beforehand:

_x000D_
_x000D_
const wizard = document.querySelector('#wizard');_x000D_
wizard.addEventListener('click', ({ target }) => {_x000D_
  // Make sure the clicked element is a <li>_x000D_
  if (!target.matches('li')) return;_x000D_
  _x000D_
  const lis = [...wizard.children];_x000D_
  const index = lis.indexOf(target);_x000D_
  console.log(index);_x000D_
});
_x000D_
<ul id="wizard">_x000D_
    <li>Step 1</li>_x000D_
    <li>Step 2</li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

Absolute and Flexbox in React Native

The first step would be to add

position: 'absolute',

then if you want the element full width, add

left: 0,
right: 0,

then, if you want to put the element in the bottom, add

bottom: 0,
// don't need set top: 0

if you want to position the element at the top, replace bottom: 0 by top: 0

Unable to connect to any of the specified mysql hosts. C# MySQL

If you are accessing the live database by using localhost URL then it will not work. Please deploy your service or website on IIS and create URL and then access the database by using new URL, It will work.

Using .htaccess to make all .html pages to run as .php files?

Normally you should add:

Options +ExecCGI
 AddType application/x-httpd-php .php .html
 AddHandler x-httpd-php5 .php .html

However for GoDaddy shared hosting (php-cgi), you need to add also these lines:

AddHandler fcgid-script .html
FCGIWrapper /usr/local/cpanel/cgi-sys/php5 .html

Source: Parse HTML As PHP Using HTACCESS File On Godaddy.

Spring - applicationContext.xml cannot be opened because it does not exist

I placed the applicationContext.xml in the src/main/java folder and it worked

How to clear memory to prevent "out of memory error" in excel vba?

I had a similar problem that I resolved myself.... I think it was partially my code hogging too much memory while too many "big things"

in my application - the workbook goes out and grabs another departments "daily report".. and I extract out all the information our team needs (to minimize mistakes and data entry).

I pull in their sheets directly... but I hate the fact that they use Merged cells... which I get rid of (ie unmerge, then find the resulting blank cells, and fill with the values from above)

I made my problem go away by

a)unmerging only the "used cells" - rather than merely attempting to do entire column... ie finding the last used row in the column, and unmerging only this range (there is literally 1000s of rows on each of the sheet I grab)

b) Knowing that the undo only looks after the last ~16 events... between each "unmerge" - i put 15 events which clear out what is stored in the "undo" to minimize the amount of memory held up (ie go to some cell with data in it.. and copy// paste special value... I was GUESSING that the accumulated sum of 30sheets each with 3 columns worth of data might be taxing memory set as side for undoing

Yes it doesn't allow for any chance of an Undo... but the entire purpose is to purge the old information and pull in the new time sensitive data for analysis so it wasn't an issue

Sound corny - but my problem went away

CSS scale height to match width - possibly with a formfactor

For this, you will need to utilise JavaScript, or rely on the somewhat supported calc() CSS expression.

window.addEventListener("resize", function(e) {
    var mapElement = document.getElementById("map");
    mapElement.style.height = mapElement.offsetWidth * 1.72;
});

Or using CSS calc (see support here: http://caniuse.com/calc)

#map {
    width: 100%;
    height: calc(100vw * 1.72)
}

How can I get date in application run by node.js?

You do that as you would in a browser:

_x000D_
_x000D_
    var datetime = new Date();_x000D_
    console.log(datetime);
_x000D_
_x000D_
_x000D_

jQuery location href

Ideally, you want to be using window.location.replace(...).

See this answer here for a full explanation: How do I redirect to another webpage?

Using event.target with React components

First argument in update method is SyntheticEvent object that contains common properties and methods to any event, it is not reference to React component where there is property props.

if you need pass argument to update method you can do it like this

onClick={ (e) => this.props.onClick(e, 'home', 'Home') }

and get these arguments inside update method

update(e, space, txt){
   console.log(e.target, space, txt);
}

Example


event.target gives you the native DOMNode, then you need to use the regular DOM APIs to access attributes. For instance getAttribute or dataset

<button 
  data-space="home" 
  className="home" 
  data-txt="Home" 
  onClick={ this.props.onClick } 
/> 
  Button
</button>

onClick(e) {
   console.log(e.target.dataset.txt, e.target.dataset.space);
}

Example

How to run an external program, e.g. notepad, using hyperlink?

The reasonable way how to launch apps from HTML is through url schemes. So you can launch email via mailto: links and irc through irc: links. Individual apps can implement these schemes, but I'm not sure WinMerge does this.

Using Python, find anagrams for a list of words

def findanagranfromlistofwords(li):
    dict = {}
    index=0
    for i in range(0,len(li)):
        originalfirst = li[index]
        sortedfirst = ''.join(sorted(str(li[index])))
        for j in range(index+1,len(li)):
            next = ''.join(sorted(str(li[j])))
            print next
            if sortedfirst == next:
                dict.update({originalfirst:li[j]})
                print "dict = ",dict
        index+=1

    print dict

findanagranfromlistofwords(["car", "tree", "boy", "girl", "arc"])

What is useState() in React?

useState is a Hook that allows you to have state variables in functional components.

There are two types of components in React: class and functional components.

Class components are ES6 classes that extend from React.Component and can have state and lifecycle methods:

class Message extends React.Component {
constructor(props) {
super(props);
this.state = {
  message: ‘’    
 };
}

componentDidMount() {
/* ... */
 }

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

Functional components are functions that just accept arguments as the properties of the component and return valid JSX:

function Message(props) {
  return <div>{props.message}</div>
 }
// Or as an arrow function
const Message = (props) =>  <div>{props.message}</div>

As you can see, there are no state or lifecycle methods.

How do I clone a generic List in Java?

List<String> shallowClonedList = new ArrayList<>(listOfStrings);

Keep in mind that this is only a shallow not a deep copy, ie. you get a new list, but the entries are the same. This is no problem for simply strings. Get's more tricky when the list entries are objects themself.

iOS 8 UITableView separator inset 0 not working

This is the code that's working for me, in Swift:

override func viewDidLoad() 
{
    super.viewDidLoad()
    ...
    if tableView.respondsToSelector("setSeparatorInset:") {
        tableView.separatorInset = UIEdgeInsetsZero
    }
}

func tableView(tableView: UITableView, willDisplayCell cell: UITableViewCell,forRowAtIndexPath indexPath: NSIndexPath)
{
    if cell.respondsToSelector("setSeparatorInset:") {
        cell.separatorInset.left = CGFloat(0.0)
    }
    if tableView.respondsToSelector("setLayoutMargins:") {
        tableView.layoutMargins = UIEdgeInsetsZero
    }
    if cell.respondsToSelector("setLayoutMargins:") {
        cell.layoutMargins.left = CGFloat(0.0)
    }
}

This seems the cleanest to me (for now), as all the cell/tableView edge/margin adjustments are done in the tableView:willDisplayCell:forRowAtIndexPath: method, without cramming unneccessary code into tableView:cellForRowAtIndexPath:.

Btw, I'm only setting the cell's left separatorInset/layoutMargins, because in this case I don't want to screw up my constraints that I have set up in my cell.

Code updated to Swift 2.2 :

 override func viewDidLoad() {
   super.viewDidLoad()       

    if tableView.respondsToSelector(Selector("setSeparatorInset:")) {
      tableView.separatorInset = UIEdgeInsetsZero
        }
    }

 override func tableView(tableView: UITableView, willDisplayCell cell: UITableViewCell,forRowAtIndexPath indexPath: NSIndexPath) {
        if cell.respondsToSelector(Selector("setSeparatorInset:")) {
            cell.separatorInset.left = CGFloat(0.0)
        }
        if tableView.respondsToSelector(Selector("setLayoutMargins:")) {
            tableView.layoutMargins = UIEdgeInsetsZero
        }
        if cell.respondsToSelector(Selector("setLayoutMargins:")) {
            cell.layoutMargins.left = CGFloat(0.0)
        }
    }

How to solve munmap_chunk(): invalid pointer error in C++

This happens when the pointer passed to free() is not valid or has been modified somehow. I don't really know the details here. The bottom line is that the pointer passed to free() must be the same as returned by malloc(), realloc() and their friends. It's not always easy to spot what the problem is for a novice in their own code or even deeper in a library. In my case, it was a simple case of an undefined (uninitialized) pointer related to branching.

The free() function frees the memory space pointed to by ptr, which must have been returned by a previous call to malloc(), calloc() or realloc(). Otherwise, or if free(ptr) has already been called before, undefined behavior occurs. If ptr is NULL, no operation is performed. GNU 2012-05-10 MALLOC(3)

char *words; // setting this to NULL would have prevented the issue

if (condition) {
    words = malloc( 512 );

    /* calling free sometime later works here */

    free(words)
} else {

    /* do not allocate words in this branch */
}

/* free(words);  -- error here --
*** glibc detected *** ./bin: munmap_chunk(): invalid pointer: 0xb________ ***/

There are many similar questions here about the related free() and rellocate() functions. Some notable answers providing more details:

*** glibc detected *** free(): invalid next size (normal): 0x0a03c978 ***
*** glibc detected *** sendip: free(): invalid next size (normal): 0x09da25e8 ***
glibc detected, realloc(): invalid pointer


IMHO running everything in a debugger (Valgrind) is not the best option because errors like this are often caused by inept or novice programmers. It's more productive to figure out the issue manually and learn how to avoid it in the future.

C# - How to convert string to char?

char[] myChar = theString.ToCharArray();

React - Component Full Screen (with height 100%)

I managed this with a css class in my app.css

.fill-window {
    height: 100%;
    position: absolute;
    left: 0;
    width: 100%;
    overflow: hidden;
}

Apply it to your root element in your render() method

render() {
   return ( <div className="fill-window">{content}</div> );
}

Or inline

render() {
   return (
      <div style={{ height: '100%', position: 'absolute', left: '0px', width: '100%', overflow: 'hidden'}}>
          {content}
      </div>
   );
}

How to remove indentation from an unordered list item?

I have the same problem with a footer I'm trying to divide up. I found that this worked for me by trying few of above suggestions combined:

footer div ul {
    list-style-position: inside;
    padding-left: 0;
}

This seems to keep it to the left under my h1 and the bullet points inside the div rather than outside to the left.

WHERE Clause to find all records in a specific month

As an alternative to the MONTH and YEAR functions, a regular WHERE clause will work too:

select *
from yourtable
where '2009-01-01' <= datecolumn and datecolumn < '2009-02-01'

No Creators, like default construct, exist): cannot deserialize from Object value (no delegate- or property-based Creator

If you're using Lombok on a POJO model, make sure you have these annotations:

@Getter
@Builder
@NoArgsConstructor
@AllArgsConstructor

It could vary, but make sure @Getter and especially @NoArgsConstructor.

Call a REST API in PHP

as @Christoph Winkler mentioned this is a base class for achieving it:

curl_helper.php

// This class has all the necessary code for making API calls thru curl library

class CurlHelper {

// This method will perform an action/method thru HTTP/API calls
// Parameter description:
// Method= POST, PUT, GET etc
// Data= array("param" => "value") ==> index.php?param=value
public static function perform_http_request($method, $url, $data = false)
{
    $curl = curl_init();

    switch ($method)
    {
        case "POST":
            curl_setopt($curl, CURLOPT_POST, 1);

            if ($data)
                curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
            break;
        case "PUT":
            curl_setopt($curl, CURLOPT_PUT, 1);
            break;
        default:
            if ($data)
                $url = sprintf("%s?%s", $url, http_build_query($data));
    }

    // Optional Authentication:
    //curl_setopt($curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
    //curl_setopt($curl, CURLOPT_USERPWD, "username:password");

    curl_setopt($curl, CURLOPT_URL, $url);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);

    $result = curl_exec($curl);

    curl_close($curl);

    return $result;
}

}

Then you can always include the file and use it e.g.: any.php

    require_once("curl_helper.php");
    ...
    $action = "GET";
    $url = "api.server.com/model"
    echo "Trying to reach ...";
    echo $url;
    $parameters = array("param" => "value");
    $result = CurlHelper::perform_http_request($action, $url, $parameters);
    echo print_r($result)

Spring cannot find bean xml configuration file when it does exist

I also had a similar problem but because of a bit different cause so sharing here in case it can help anybody.

My file location

beans.xml file

How I was using

ClassPathXmlApplicationContext("beans.xml");

There are two solutions

  1. Take the beans.xml out of package and put in default package.
  2. Specify package name while using it viz.

ClassPathXmlApplicationContext("com/mypackage/beans.xml");

How to make a pure css based dropdown menu?

Create simple drop-down menu using HTML and CSS

CSS:

<style>
.dropdown {
    position: relative;
    display: inline-block;
}

.dropdown-content {
    display: none;
    position: absolute;
    background-color: #f9f9f9;
    min-width: 160px;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
    padding: 12px 16px;
    z-index: 1;
}

.dropdown:hover .dropdown-content {
    display: block;
}
</style>

and HTML:

<div class="dropdown">
  <span>Mouse over me</span>
  <div class="dropdown-content">
    <p>Hello World!</p>
  </div>
</div>

View demo online

Javascript ES6/ES5 find in array and change

You can use findIndex to find the index in the array of the object and replace it as required:

var item = {...}
var items = [{id:2}, {id:2}, {id:2}];

var foundIndex = items.findIndex(x => x.id == item.id);
items[foundIndex] = item;

This assumes unique IDs. If your IDs are duplicated (as in your example), it's probably better if you use forEach:

items.forEach((element, index) => {
    if(element.id === item.id) {
        items[index] = item;
    }
});

Iterate through pairs of items in a Python list

To do that you should do:

a =  [5, 7, 11, 4, 5]
for i in range(len(a)-1):
    print [a[i], a[i+1]]

How to set null value to int in c#?

int does not allow null, use-

int? value = 0  

or use

Nullable<int> value

jquery to loop through table rows and cells, where checkob is checked, concatenate

UPDATED

I've updated your demo: http://jsfiddle.net/terryyounghk/QS56z/18/

Also, I've changed two ^= to *=. See http://api.jquery.com/category/selectors/

And note the :checked selector. See http://api.jquery.com/checked-selector/

function createcodes() {

    //run through each row
    $('.authors-list tr').each(function (i, row) {

        // reference all the stuff you need first
        var $row = $(row),
            $family = $row.find('input[name*="family"]'),
            $grade = $row.find('input[name*="grade"]'),
            $checkedBoxes = $row.find('input:checked');

        $checkedBoxes.each(function (i, checkbox) {
            // assuming you layout the elements this way, 
            // we'll take advantage of .next()
            var $checkbox = $(checkbox),
                $line = $checkbox.next(),
                $size = $line.next();

            $line.val(
                $family.val() + ' ' + $size.val() + ', ' + $grade.val()
            );

        });

    });
}

How do I concatenate two strings in C?

You cannot add string literals like that in C. You have to create a buffer of size of string literal one + string literal two + a byte for null termination character and copy the corresponding literals to that buffer and also make sure that it is null terminated. Or you can use library functions like strcat.

Center a position:fixed element

left: 0;
right: 0;

Was not working under IE7.

Changed to

left:auto;
right:auto;

Started working but in the rest browsers it stop working! So used this way for IE7 below

if ($.browser.msie && parseInt($.browser.version, 10) <= 7) {                                
  strAlertWrapper.css({position:'fixed', bottom:'0', height:'auto', left:'auto', right:'auto'});
}

isolating a sub-string in a string before a symbol in SQL Server 2008

DECLARE @dd VARCHAR(200) = 'Net Operating Loss - 2007';

SELECT SUBSTRING(@dd, 1, CHARINDEX('-', @dd) -1) F1,
       SUBSTRING(@dd, CHARINDEX('-', @dd) +1, LEN(@dd)) F2

How do I read / convert an InputStream into a String in Java?

Here's my Java 8 based solution, which uses the new Stream API to collect all lines from an InputStream:

public static String toString(InputStream inputStream) {
    BufferedReader reader = new BufferedReader(
        new InputStreamReader(inputStream));
    return reader.lines().collect(Collectors.joining(
        System.getProperty("line.separator")));
}

jQuery click function doesn't work after ajax call?

$('body').delegate('.deletelanguage','click',function(){
    alert("success");
});

or

$('body').on('click','.deletelanguage',function(){
    alert("success");
});

JavaFX "Location is required." even though it is in the same package

I have found all of the above solutions work just fine because they trigger your IDE to rebuild the project. No magic involved.

The "real" solution for this issue is that you should just ditch your previous build directory.

  • If you are using Maven, just delete the target folder (or do a mvn clean)!
  • If you're using ANT, delete that respective folder (I think it's called out)!
  • If you're using Gradle, delete the build folder!

Android: ScrollView vs NestedScrollView

In addition to the nested scrolling NestedScrollView added one major functionality, which could even make it interesting outside of nested contexts: It has build in support for OnScrollChangeListener. Adding a OnScrollChangeListener to the original ScrollView below API 23 required subclassing ScrollView or messing around with the ViewTreeObserver of the ScrollView which often means even more work than subclassing. With NestedScrollView it can be done using the build-in setter.

How do I bind Twitter Bootstrap tooltips to dynamically created elements?

For me, only catching the mouseenter event was a bit buggy, and the tooltip was not showing/hiding properly. I had to write this, and it is now working perfectly:

$(document).on('mouseenter','[rel=tooltip]', function(){
    $(this).tooltip('show');
});

$(document).on('mouseleave','[rel=tooltip]', function(){
    $(this).tooltip('hide');
});

How to make a JSON call to a url?

In modern-day JS, you can get your JSON data by calling ES6's fetch() on your URL and then using ES7's async/await to "unpack" the Response object from the fetch to get the JSON data like so:

_x000D_
_x000D_
const getJSON = async url => {
  try {
    const response = await fetch(url);
    if(!response.ok) // check if response worked (no 404 errors etc...)
      throw new Error(response.statusText);

    const data = await response.json(); // get JSON from the response
    return data; // returns a promise, which resolves to this data value
  } catch(error) {
    return error;
  }
}

console.log("Fetching data...");
getJSON("https://soundcloud.com/oembed?url=http%3A//soundcloud.com/forss/flickermood&format=json").then(data => {
  console.log(data);
}).catch(error => {
  console.error(error);
});
_x000D_
_x000D_
_x000D_

The above method can be simplified down to a few lines if you ignore the exception/error handling (usually not recommended as this can lead to unwanted errors):

_x000D_
_x000D_
const getJSON = async url => {
  const response = await fetch(url);
  return response.json(); // get JSON from the response 
}

console.log("Fetching data...");
getJSON("https://soundcloud.com/oembed?url=http%3A//soundcloud.com/forss/flickermood&format=json")
  .then(data => console.log(data));
_x000D_
_x000D_
_x000D_

Unable to Connect to GitHub.com For Cloning

You are probably behind a firewall. Try cloning via https – that has a higher chance of not being blocked:

git clone https://github.com/angular/angular-phonecat.git

Convert string to decimal number with 2 decimal places in Java

Use BigDecimal:

new BigDecimal(theInputString);

It retains all decimal digits. And you are sure of the exact representation since it uses decimal base, not binary base, to store the precision/scale/etc.

And it is not subject to precision loss like float or double are, unless you explicitly ask it to.

Opening PDF String in new window with javascript

One suggestion is that use a pdf library like PDFJS.

Yo have to append, the following "data:application/pdf;base64" + your pdf String, and set the src of your element to that.

Try with this example:

var pdfsrc = "data:application/pdf;base64" + "67987yiujkhkyktgiyuyhjhgkhgyi...n"

<pdf-element id="pdfOpen" elevation="5" downloadable src="pdfsrc" ></pdf-element>

Hope it helps :)

In Java, what purpose do the keywords `final`, `finally` and `finalize` fulfil?

The meaning of final in java is: -applied to a variable means that the respective variable once initialized can no longer be modified

private final double numer = 12;

If you try to modify this value, you will get an error.

-applied to a method means that the respective method can't be override

 public final void displayMsg()
    {
        System.out.println("I'm in Base class - displayMsg()");
    }

But final method can be inherited because final keyword restricts the redefinition of the method.

-applied to a class means that the respective class can't be extended.

class Base
{

    public void displayMsg()
    {
        System.out.println("I'm in Base class - displayMsg()");
    }
}

The meaning of finally is :

class TestFinallyBlock{  
  public static void main(String args[]){  
  try{  
   int data=25/5;  
   System.out.println(data);  
  }  
  catch(NullPointerException e){System.out.println(e);}  
  finally{System.out.println("finally block is always executed");}  
  System.out.println("rest of the code...");  
  }  
} 

in this exemple even if the try-catch is executed or not, what is inside of finally will always be executed. The meaning of finalize:

class FinalizeExample{  
public void finalize(){System.out.println("finalize called");}  
public static void main(String[] args){  
FinalizeExample f1=new FinalizeExample();  
FinalizeExample f2=new FinalizeExample();  
f1=null;  
f2=null;  
System.gc();  
}}  

before calling the Garbage Collector.

How to subscribe to an event on a service in Angular2?

Update: I have found a better/proper way to solve this problem using a BehaviorSubject or an Observable rather than an EventEmitter. Please see this answer: https://stackoverflow.com/a/35568924/215945

Also, the Angular docs now have a cookbook example that uses a Subject.


Original/outdated/wrong answer: again, don't use an EventEmitter in a service. That is an anti-pattern.

Using beta.1... NavService contains the EventEmiter. Component Navigation emits events via the service, and component ObservingComponent subscribes to the events.

nav.service.ts

import {EventEmitter} from 'angular2/core';
export class NavService {
  navchange: EventEmitter<number> = new EventEmitter();
  constructor() {}
  emitNavChangeEvent(number) {
    this.navchange.emit(number);
  }
  getNavChangeEmitter() {
    return this.navchange;
  }
}

components.ts

import {Component} from 'angular2/core';
import {NavService} from '../services/NavService';

@Component({
  selector: 'obs-comp',
  template: `obs component, item: {{item}}`
})
export class ObservingComponent {
  item: number = 0;
  subscription: any;
  constructor(private navService:NavService) {}
  ngOnInit() {
    this.subscription = this.navService.getNavChangeEmitter()
      .subscribe(item => this.selectedNavItem(item));
  }
  selectedNavItem(item: number) {
    this.item = item;
  }
  ngOnDestroy() {
    this.subscription.unsubscribe();
  }
}

@Component({
  selector: 'my-nav',
  template:`
    <div class="nav-item" (click)="selectedNavItem(1)">nav 1 (click me)</div>
    <div class="nav-item" (click)="selectedNavItem(2)">nav 2 (click me)</div>
  `,
})
export class Navigation {
  item = 1;
  constructor(private navService:NavService) {}
  selectedNavItem(item: number) {
    console.log('selected nav item ' + item);
    this.navService.emitNavChangeEvent(item);
  }
}

Plunker

correct configuration for nginx to localhost?

Fundamentally you hadn't declare location which is what nginx uses to bind URL with resources.

 server {
            listen       80;
            server_name  localhost;

            access_log  logs/localhost.access.log  main;

            location / {
                root /var/www/board/public;
                index index.html index.htm index.php;
            }
       }

HTTPS setup in Amazon EC2

One of the best resources I found was using let's encrypt, you do not need ELB nor cloudfront for your EC2 instance to have HTTPS, just follow the following simple instructions: let's encrypt Login to your server and follow the steps in the link.

It is also important as mentioned by others that you have port 443 opened by editing your security groups

You can view your certificate or any other website's by changing the site name in this link

Please do not forget that it is only valid for 90 days

How to pass variable number of arguments to printf/sprintf

Have a look at the example http://www.cplusplus.com/reference/clibrary/cstdarg/va_arg/, they pass the number of arguments to the method but you can ommit that and modify the code appropriately (see the example).

Sort arrays of primitive types in descending order

There's been some confusion about Arrays.asList in the other answers. If you say

double[] arr = new double[]{6.0, 5.0, 11.0, 7.0};
List xs = Arrays.asList(arr);
System.out.println(xs.size());  // prints 1

then you'll have a List with 1 element. The resulting List has the double[] array as its own element. What you want is to have a List<Double> whose elements are the elements of the double[].

Unfortunately, no solution involving Comparators will work for a primitive array. Arrays.sort only accepts a Comparator when being passed an Object[]. And for the reasons describe above, Arrays.asList won't let you make a List out of the elements of your array.

So despite my earlier answer which the comments below reference, there's no better way than manually reversing the array after sorting. Any other approach (such as copying the elements into a Double[] and reverse-sorting and copying them back) would be more code and slower.

How to pass parameters or arguments into a gradle task

You should consider passing the -P argument in invoking Gradle.

From Gradle Documentation :

--project-prop Sets a project property of the root project, for example -Pmyprop=myvalue. See Section 14.2, “Gradle properties and system properties”.

Considering this build.gradle

task printProp << {
    println customProp
}

Invoking Gradle -PcustomProp=myProp will give this output :

$ gradle -PcustomProp=myProp printProp
:printProp
myProp

BUILD SUCCESSFUL

Total time: 3.722 secs

This is the way I found to pass parameters.

How to get the name of a class without the package?

Class.getSimpleName()

Returns the simple name of the underlying class as given in the source code. Returns an empty string if the underlying class is anonymous.

The simple name of an array is the simple name of the component type with "[]" appended. In particular the simple name of an array whose component type is anonymous is "[]".

It is actually stripping the package information from the name, but this is hidden from you.

Export Postgresql table data using pgAdmin

In the pgAdmin4, Right click on table select backup like this

enter image description here

After that into the backup dialog there is Dump options tab into that there is section queries you can select Use Insert Commands which include all insert queries as well in the backup.

enter image description here

Get first element from a dictionary

For anyone coming to this that wants a linq-less way to get an element from a dictionary

var d = new Dictionary<string, string>();
d.Add("a", "b");
var e = d.GetEnumerator();
e.MoveNext();
var anElement = e.Current;
// anElement/e.Current is a KeyValuePair<string,string>
// where Key = "a", Value = "b"

I'm not sure if this is implementation specific, but if your Dictionary doesn't have any elements, Current will contain a KeyValuePair<string, string> where both the key and value are null.

(I looked at the logic behind linq's First method to come up with this, and tested it via LinqPad 4)

CSS force image resize and keep aspect ratio

You can create a div like this:

<div class="image" style="background-image:url('/to/your/image')"></div>

And use this css to style it:

height: 100%;
width: 100%;
background-position: center center;
background-repeat: no-repeat;
background-size: contain; // this can also be cover

Multiple files upload (Array) with CodeIgniter 2.0

    public function imageupload() 
    {

      $count = count($_FILES['userfile']['size']);

  $config['upload_path'] = './uploads/';
  $config['allowed_types'] = 'gif|jpg|png|bmp';
  $config['max_size']   = '0';
  $config['max_width']  = '0';
  $config['max_height']  = '0';

  $config['image_library'] = 'gd2';
  $config['create_thumb'] = TRUE;
  $config['maintain_ratio'] = FALSE;
  $config['width'] = 50;
  $config['height'] = 50;

  foreach($_FILES as $key=>$value)
  { 
     for($s=0; $s<=$count-1; $s++)
     {
     $_FILES['userfile']['name']=$value['name'][$s];
     $_FILES['userfile']['type']    = $value['type'][$s];
     $_FILES['userfile']['tmp_name'] = $value['tmp_name'][$s]; 
     $_FILES['userfile']['error']       = $value['error'][$s];
     $_FILES['userfile']['size']    = $value['size'][$s];  

         $this->load->library('upload', $config);

         if ($this->upload->do_upload('userfile'))
         {
           $data['userfile'][$i] = $this->upload->data();
       $full_path = $data['userfile']['full_path'];


           $config['source_image'] = $full_path;
           $config['new_image'] = './uploads/resiezedImage';

           $this->load->library('image_lib', $config);
           $this->image_lib->resize(); 
           $this->image_lib->clear();

         }
         else
         {
           $data['upload_errors'][$i] = $this->upload->display_errors();
         } 
     }
  }
}

Plotting multiple lines, in different colors, with pandas dataframe

Another simple way is to use the pivot function to format the data as you need first.

df.plot() does the rest

df = pd.DataFrame([
    ['red', 0, 0],
    ['red', 1, 1],
    ['red', 2, 2],
    ['red', 3, 3],
    ['red', 4, 4],
    ['red', 5, 5],
    ['red', 6, 6],
    ['red', 7, 7],
    ['red', 8, 8],
    ['red', 9, 9],
    ['blue', 0, 0],
    ['blue', 1, 1],
    ['blue', 2, 4],
    ['blue', 3, 9],
    ['blue', 4, 16],
    ['blue', 5, 25],
    ['blue', 6, 36],
    ['blue', 7, 49],
    ['blue', 8, 64],
    ['blue', 9, 81],
], columns=['color', 'x', 'y'])

df = df.pivot(index='x', columns='color', values='y')

df.plot()

result

pivot effectively turns the data into:

enter image description here

How to run a subprocess with Python, wait for it to exit and get the full stdout as a string?

I'd try something like:

#!/usr/bin/python
from __future__ import print_function

import shlex
from subprocess import Popen, PIPE

def shlep(cmd):
    '''shlex split and popen
    '''
    parsed_cmd = shlex.split(cmd)
    ## if parsed_cmd[0] not in approved_commands:
    ##    raise ValueError, "Bad User!  No output for you!"
    proc = Popen(parsed_command, stdout=PIPE, stderr=PIPE)
    out, err = proc.communicate()
    return (proc.returncode, out, err)

... In other words let shlex.split() do most of the work. I would NOT attempt to parse the shell's command line, find pipe operators and set up your own pipeline. If you're going to do that then you'll basically have to write a complete shell syntax parser and you'll end up doing an awful lot of plumbing.

Of course this raises the question, why not just use Popen with the shell=True (keyword) option? This will let you pass a string (no splitting nor parsing) to the shell and still gather up the results to handle as you wish. My example here won't process any pipelines, backticks, file descriptor redirection, etc that might be in the command, they'll all appear as literal arguments to the command. Thus it is still safer then running with shell=True ... I've given a silly example of checking the command against some sort of "approved command" dictionary or set --- through it would make more sense to normalize that into an absolute path unless you intend to require that the arguments be normalized prior to passing the command string to this function.

Is there a .NET/C# wrapper for SQLite?

sqlite-net is an open source, minimal library to allow .NET and Mono applications to store data in SQLite 3 databases. More information at the wiki page.

It is written in C# and is meant to be simply compiled in with your projects. It was first designed to work with MonoTouch on the iPhone, but has grown up to work on all the platforms (Mono for Android, .NET, Silverlight, WP7, WinRT, Azure, etc.).

It is available as a Nuget package, where it is the 2nd most popular SQLite package with over 60,000 downloads as of 2014.

sqlite-net was designed as a quick and convenient database layer. Its design follows from these goals:

  • Very easy to integrate with existing projects and with MonoTouch projects.
  • Thin wrapper over SQLite and should be fast and efficient. (The library should not be the performance bottleneck of your queries.)
  • Very simple methods for executing CRUD operations and queries safely (using parameters) and for retrieving the results of those query in a strongly typed fashion.
  • Works with your data model without forcing you to change your classes. (Contains a small reflection-driven ORM layer.)
  • 0 dependencies aside from a compiled form of the sqlite2 library.

Non-goals include:

  • Not an ADO.NET implementation. This is not a full SQLite driver. If you need that, use System.Data.SQLite.

How to change a css class style through Javascript?

<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
        $("div").addClass(function(){
            return "par" ;
    });
});
</script>
<style>
.par {
    color: blue;
}
</style>
</head>
<body>
<div class="test">This is a paragraph.</div>
</body>
</html>

css transform, jagged edges in chrome

I've tried the all solutions in here and didn't work in my case. But using

will-change: transform;

fixes the jagge issue.

Validate select box

<select id='bookcategory' class="form-control" required="">
                    <option value="" disabled="disabled">Category</option>
                    <option value="1">LITERATURE & FICTION</option>
                    <option value="2">NON FICTION</option>
                    <option value="3">ACADEMIC</option>
            <option value="4">CHILDREN & TEENS</option>

                </select>

HTML form validation can be performed automatically by the browser. Try the above code:
The rest all will be done automatically, no need to create any js functions just this dropdown and a submit button.

IE8 crashes when loading website - res://ieframe.dll/acr_error.htm

I had this happening with a Drupal theme. None of the many suggestions on various threads (change IE security settings or some other advanced settings, update Java, update Flash, fiddle with registry, remove certain Windows updates, check plugins, scan for malware, completely reinstall IE8) worked for me.

In this case, it turned out to be a problem with setting a background-image on a body element - changing body to an html element fixed things. It is apparently related to loading respond.js - try putting that at the bottom.

What is the meaning of the prefix N in T-SQL statements and when should I use it?

Assuming the value is nvarchar type for that only we are using N''

Can you install and run apps built on the .NET framework on a Mac?

You can use a .Net environment Visual studio, Take a look at the differences with the PC version.

A lighter editor would be Visual Code

Alternatives :

  1. Installing the Mono Project runtime . It allows you to re-compile the code and run it on a Mac, but this requires various alterations to the codebase, as the fuller .Net Framework is not available. (Also, WPF applications aren't supported here either.)

  2. Virtual machine (VMWare Fusion perhaps)

  3. Update your codebase to .Net Core, (before choosing this option take a look at this migration process)

    • .Net Core 3.1 is an open-source, free and available on Window, MacOs and Linux

    • As of September 14, a release candidate 1 of .Net Core 5.0 has been deployed on Window, MacOs and Linux.

[1] : Release candidate (RC) : releases providing early access to complete features. These releases are supported for production use when they have a go-live license

SQL Server reports 'Invalid column name', but the column is present and the query works through management studio

I've gotten this error when running a scalar function using a table value, but the Select statement in my scalar function RETURN clause was missing the "FROM table" portion. :facepalms:

Unable to execute dex: Multiple dex files define

I got this error for another reason. I was mistaking adding both the v4 AND the v13 support library. This was not necessary for me since my minSdkVersion is 15.

I fixed it by only including the v13 support library. Also, make sure to check mark the library in your exported library build path in eclipse. I also moved it to the top.

Apache VirtualHost and localhost

localhost will always redirect to 127.0.0.1. You can trick this by naming your other VirtualHost to other local loop-back address, such as 127.0.0.2. Make sure you also change the corresponding hosts file to implement this.

For example, my httpd-vhosts.conf looks like this:

<VirtualHost 127.0.0.2:80>
    DocumentRoot "D:/6. App Data/XAMPP Shared/htdocs/intranet"
    ServerName intranet.dev
    ServerAlias www.intranet.dev
    ErrorLog "logs/intranet.dev-error.log"
    CustomLog "logs/intranet.dec-access.log" combined

    <Directory "D:/6. App Data/XAMPP Shared/htdocs/intranet">
        Options Indexes FollowSymLinks ExecCGI Includes
        Order allow,deny
        Allow from all
        AllowOverride All
        Require all granted
    </Directory>
</VirtualHost>

(Notice that in <VirtualHost> section I typed 127.0.0.2:80. It means that this block of VirtualHost will only affects requests to IP address 127.0.0.2 port 80, which is the default port for HTTP.

To route the name intranet.dev properly, my hosts entry line is like this:

127.0.0.2 intranet.dev

This way, it will prevent you from creating another VirtualHost block for localhost, which is unnecessary.

Setting up enviromental variables in Windows 10 to use java and javac

Here are the typical steps to set JAVA_HOME on Windows 10.

  1. Search for Advanced System Settings in your windows Search box. Click on Advanced System Settings.
  2. Click on Environment variables button: Environment Variables popup will open.
  3. Goto system variables session, and click on New button to create new variable (HOME_PATH), then New System Variables popup will open.
  4. Give Variable Name: JAVA_HOME, and Variable value : Your Java SDK home path. Ex: C:\Program Files\java\jdk1.8.0_151 Note: It should not include \bin. Then click on OK button.
  5. Now you are able to see your JAVA_HOME in system variables list. (If you are not able to, try doing it again.)
  6. Select Path (from system variables list) and click on Edit button, A new pop will opens (Edit Environment Variables). It was introduced in windows 10.
  7. Click on New button and give %JAVA_HOME%\bin at highlighted field and click Ok button.

You can find complete tutorials on my blog :

How to set JAVA_HOME in 64 bit Windows 10 OS

When should use Readonly and Get only properties

Methods suggest something has to happen to return the value, properties suggest that the value is already there. This is a rule of thumb, sometimes you might want a property that does a little work (i.e. Count), but generally it's a useful way to decide.

Set the space between Elements in Row Flutter

Row(
 children: <Widget>[
  Flexible(
   child: TextFormField()),
  Container(width: 20, height: 20),
  Flexible(
   child: TextFormField())
 ])

This works for me, there are 3 widgets inside row: Flexible, Container, Flexible

How to delete multiple rows in SQL where id = (x to y)

If you need to delete based on a list, you can use IN:

DELETE FROM your_table
WHERE id IN (value1, value2, ...);

If you need to delete based on the result of a query, you can also use IN:

DELETE FROM your_table
WHERE id IN (select aColumn from ...);

(Notice that the subquery must return only one column)

If you need to delete based on a range of values, either you use BETWEEN or you use inequalities:

DELETE FROM your_table
WHERE id BETWEEN bottom_value AND top_value;

or

DELETE FROM your_table
WHERE id >= a_value AND id <= another_value;

Insert multiple rows with one query MySQL

While inserting multiple rows with a single INSERT statement is generally faster, it leads to a more complicated and often unsafe code. Below I present the best practices when it comes to inserting multiple records in one go using PHP.

To insert multiple new rows into the database at the same time, one needs to follow the following 3 steps:

  1. Start transaction (disable autocommit mode)
  2. Prepare INSERT statement
  3. Execute it multiple times

Using database transactions ensures that the data is saved in one piece and significantly improves performance.

How to properly insert multiple rows using PDO

PDO is the most common choice of database extension in PHP and inserting multiple records with PDO is quite simple.

$pdo = new \PDO("mysql:host=localhost;dbname=test;charset=utf8mb4", 'user', 'password', [
    \PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION,
    \PDO::ATTR_EMULATE_PREPARES => false
]);

// Start transaction
$pdo->beginTransaction();

// Prepare statement
$stmt = $pdo->prepare('INSERT 
    INTO `pxlot` (realname,email,address,phone,status,regtime,ip) 
    VALUES (?,?,?,?,?,?,?)');

// Perform execute() inside a loop
// Sample data coming from a fictitious data set, but the data can come from anywhere
foreach ($dataSet as $data) {
    // All seven parameters are passed into the execute() in a form of an array
    $stmt->execute([$data['name'], $data['email'], $data['address'], getPhoneNo($data['name']), '0', $data['regtime'], $data['ip']]);
}

// Commit the data into the database
$pdo->commit();

How to properly insert multiple rows using mysqli

The mysqli extension is a little bit more cumbersome to use but operates on very similar principles. The function names are different and take slightly different parameters.

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new \mysqli('localhost', 'user', 'password', 'database');
$mysqli->set_charset('utf8mb4');

// Start transaction
$mysqli->begin_transaction();

// Prepare statement
$stmt = $mysqli->prepare('INSERT 
    INTO `pxlot` (realname,email,address,phone,status,regtime,ip) 
    VALUES (?,?,?,?,?,?,?)');

// Perform execute() inside a loop
// Sample data coming from a fictitious data set, but the data can come from anywhere
foreach ($dataSet as $data) {
    // mysqli doesn't accept bind in execute yet, so we have to bind the data first
    // The first argument is a list of letters denoting types of parameters. It's best to use 's' for all unless you need a specific type
    // bind_param doesn't accept an array so we need to unpack it first using '...'
    $stmt->bind_param('sssssss', ...[$data['name'], $data['email'], $data['address'], getPhoneNo($data['name']), '0', $data['regtime'], $data['ip']]);
    $stmt->execute();
}

// Commit the data into the database
$mysqli->commit();

Performance

Both extensions offer the ability to use transactions. Executing prepared statement with transactions greatly improves performance, but it's still not as good as a single SQL query. However, the difference is so negligible that for the sake of conciseness and clean code it is perfectly acceptable to execute prepared statements multiple times. If you need a faster option to insert many records into the database at once, then chances are that PHP is not the right tool.

findViewByID returns null

In my case, findViewById returned null when I moved the call from a parent object into an adapter object instantiated by the parent. After trying tricks listed here without success, I moved the findViewById back into the parent object and passed the result as a parameter during instantiation of the adapter object. For example, I did this in parent object:

 Spinner hdSpinner = (Spinner)view.findViewById(R.id.accountsSpinner);

Then I passed the hdSpinner as a parameter during creation of the adapter object:

  mTransactionAdapter = new TransactionAdapter(getActivity(),
        R.layout.transactions_list_item, null, from, to, 0, hdSpinner);

Making authenticated POST requests with Spring RestTemplate for Android

Ok found the answer. exchange() is the best way. Oddly the HttpEntity class doesn't have a setBody() method (it has getBody()), but it is still possible to set the request body, via the constructor.

// Create the request body as a MultiValueMap
MultiValueMap<String, String> body = new LinkedMultiValueMap<String, String>();     

body.add("field", "value");

// Note the body object as first parameter!
HttpEntity<?> httpEntity = new HttpEntity<Object>(body, requestHeaders);

ResponseEntity<MyModel> response = restTemplate.exchange("/api/url", HttpMethod.POST, httpEntity, MyModel.class);

Python-Requests close http connection

As discussed here, there really isn't such a thing as an HTTP connection and what httplib refers to as the HTTPConnection is really the underlying TCP connection which doesn't really know much about your requests at all. Requests abstracts that away and you won't ever see it.

The newest version of Requests does in fact keep the TCP connection alive after your request.. If you do want your TCP connections to close, you can just configure the requests to not use keep-alive.

s = requests.session()
s.config['keep_alive'] = False

How can I disable notices and warnings in PHP within the .htaccess file?

Fortes is right, thank you.

When you have a shared hosting it is usual to obtain an 500 server error.

I have a website with Joomla and I added to the index.php:

ini_set('display_errors','off');

The error line showed in my website disappeared.

ERROR 1044 (42000): Access denied for 'root' With All Privileges

The reason i could not delete some of the users via 'drop' statement was that there is a bug in Mysql http://bugs.mysql.com/bug.php?id=62255 with hostname containing upper case letters. The solution was running following query:

DELETE FROM mysql.user where host='Some_Host_With_UpperCase_Letters';

I am still trying to figure the other issue where the root user with all permissions are unable to grant privileges to new user for particular database

Token based authentication in Web API without any user interface

ASP.Net Web API has Authorization Server build-in already. You can see it inside Startup.cs when you create a new ASP.Net Web Application with Web API template.

OAuthOptions = new OAuthAuthorizationServerOptions
{
    TokenEndpointPath = new PathString("/Token"),
    Provider = new ApplicationOAuthProvider(PublicClientId),
    AuthorizeEndpointPath = new PathString("/api/Account/ExternalLogin"),
    AccessTokenExpireTimeSpan = TimeSpan.FromDays(14),
    // In production mode set AllowInsecureHttp = false
    AllowInsecureHttp = true
};

All you have to do is to post URL encoded username and password inside query string.

/Token/userName=johndoe%40example.com&password=1234&grant_type=password

If you want to know more detail, you can watch User Registration and Login - Angular Front to Back with Web API by Deborah Kurata.

Count number of occurrences for each unique value

You should change the query to:

SELECT time_col, COUNT(time_col) As Count
FROM time_table
WHERE activity_col = 3
GROUP BY time_col

This vl works correctly.

PHP 5 disable strict standards error

In php.ini set :

error_reporting = E_ALL & ~E_NOTICE & ~E_STRICT

How to execute Table valued function

A TVF (table-valued function) is supposed to be SELECTed FROM. Try this:

select * from FN('myFunc')

How do I count the number of occurrences of a char in a String?

I had an idea similar to Mladen, but the opposite...

String s = "a.b.c.d";
int charCount = s.replaceAll("[^.]", "").length();
println(charCount);

How to force DNS refresh for a website?

So if the issue is you just created a website and your clients or any given ISP DNS is cached and doesn't show new site yet. Yes all the other stuff applies ipconfig reset browser etc. BUT here's an Idea and something I do from time to time. You can set an alternate network ISP's DNS in the tcpip properties on the NIC properties. So if your ISP is say telstra and it hasn't propagated or updated you can specify an alternate service providers dns there. if that isp dns is updated before your native one hey presto you will see new site.But there is lots of other tricks you can do to determine propagation and get mail to work prior to the DNS updating. drop me a line if any one wants to chat.

Sqlite or MySql? How to decide?

The sqlite team published an article explaining when to use sqlite that is great read. Basically, you want to avoid using sqlite when you have a lot of write concurrency or need to scale to terabytes of data. In many other cases, sqlite is a surprisingly good alternative to a "traditional" database such as MySQL.

Eclipse HotKey: how to switch between tabs?

Solved!!

Change Scheme to Microsoft Visual Studio

Window>Preferences>General>Keys

Look for Schemes dropdown

My eclipse version:

Eclipse Java EE IDE for Web Developers.

Version: Juno Service Release 1 Build id: 20120920-0800

How to convert a UTF-8 string into Unicode?

If you have a UTF-8 string, where every byte is correct ('Ö' -> [195, 0] , [150, 0]), you can use the following:

public static string Utf8ToUtf16(string utf8String)
{
    /***************************************************************
     * Every .NET string will store text with the UTF-16 encoding, *
     * known as Encoding.Unicode. Other encodings may exist as     *
     * Byte-Array or incorrectly stored with the UTF-16 encoding.  *
     *                                                             *
     * UTF-8 = 1 bytes per char                                    *
     *    ["100" for the ansi 'd']                                 *
     *    ["206" and "186" for the russian '?']                    *
     *                                                             *
     * UTF-16 = 2 bytes per char                                   *
     *    ["100, 0" for the ansi 'd']                              *
     *    ["186, 3" for the russian '?']                           *
     *                                                             *
     * UTF-8 inside UTF-16                                         *
     *    ["100, 0" for the ansi 'd']                              *
     *    ["206, 0" and "186, 0" for the russian '?']              *
     *                                                             *
     * First we need to get the UTF-8 Byte-Array and remove all    *
     * 0 byte (binary 0) while doing so.                           *
     *                                                             *
     * Binary 0 means end of string on UTF-8 encoding while on     *
     * UTF-16 one binary 0 does not end the string. Only if there  *
     * are 2 binary 0, than the UTF-16 encoding will end the       *
     * string. Because of .NET we don't have to handle this.       *
     *                                                             *
     * After removing binary 0 and receiving the Byte-Array, we    *
     * can use the UTF-8 encoding to string method now to get a    *
     * UTF-16 string.                                              *
     *                                                             *
     ***************************************************************/

    // Get UTF-8 bytes and remove binary 0 bytes (filler)
    List<byte> utf8Bytes = new List<byte>(utf8String.Length);
    foreach (byte utf8Byte in utf8String)
    {
        // Remove binary 0 bytes (filler)
        if (utf8Byte > 0) {
            utf8Bytes.Add(utf8Byte);
        }
    }

    // Convert UTF-8 bytes to UTF-16 string
    return Encoding.UTF8.GetString(utf8Bytes.ToArray());
}

In my case the DLL result is a UTF-8 string too, but unfortunately the UTF-8 string is interpreted with UTF-16 encoding ('Ö' -> [195, 0], [19, 32]). So the ANSI '–' which is 150 was converted to the UTF-16 '–' which is 8211. If you have this case too, you can use the following instead:

public static string Utf8ToUtf16(string utf8String)
{
    // Get UTF-8 bytes by reading each byte with ANSI encoding
    byte[] utf8Bytes = Encoding.Default.GetBytes(utf8String);

    // Convert UTF-8 bytes to UTF-16 bytes
    byte[] utf16Bytes = Encoding.Convert(Encoding.UTF8, Encoding.Unicode, utf8Bytes);

    // Return UTF-16 bytes as UTF-16 string
    return Encoding.Unicode.GetString(utf16Bytes);
}

Or the Native-Method:

[DllImport("kernel32.dll")]
private static extern Int32 MultiByteToWideChar(UInt32 CodePage, UInt32 dwFlags, [MarshalAs(UnmanagedType.LPStr)] String lpMultiByteStr, Int32 cbMultiByte, [Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder lpWideCharStr, Int32 cchWideChar);

public static string Utf8ToUtf16(string utf8String)
{
    Int32 iNewDataLen = MultiByteToWideChar(Convert.ToUInt32(Encoding.UTF8.CodePage), 0, utf8String, -1, null, 0);
    if (iNewDataLen > 1)
    {
        StringBuilder utf16String = new StringBuilder(iNewDataLen);
        MultiByteToWideChar(Convert.ToUInt32(Encoding.UTF8.CodePage), 0, utf8String, -1, utf16String, utf16String.Capacity);

        return utf16String.ToString();
    }
    else
    {
        return String.Empty;
    }
}

If you need it the other way around, see Utf16ToUtf8. Hope I could be of help.

Check mySQL version on Mac 10.8.5

Every time you used the mysql console, the version is shown.

 mysql -u user

Successful console login shows the following which includes the mysql server version.

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1432
Server version: 5.5.9-log Source distribution

Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

You can also check the mysql server version directly by executing the following command:

mysql --version

You may also check the version information from the mysql console itself using the version variables:

mysql> SHOW VARIABLES LIKE "%version%";

Output will be something like this:

+-------------------------+---------------------+
| Variable_name           | Value               |
+-------------------------+---------------------+
| innodb_version          | 1.1.5               |
| protocol_version        | 10                  |
| slave_type_conversions  |                     |
| version                 | 5.5.9-log           |
| version_comment         | Source distribution |
| version_compile_machine | i386                |
| version_compile_os      | osx10.4             |
+-------------------------+---------------------+
7 rows in set (0.01 sec)

You may also use this:

mysql> select @@version;

The STATUS command display version information as well.

mysql> STATUS

You can also check the version by executing this command:

mysql -v

It's worth mentioning that if you have encountered something like this:

ERROR 2002 (HY000): Can't connect to local MySQL server through socket
'/tmp/mysql.sock' (2)

you can fix it by:

sudo ln -s /Applications/MAMP/tmp/mysql/mysql.sock /tmp/mysql.sock

Is there a way to check which CSS styles are being used or not used on a web page?

Take a look at UnCSS. It helps in creating a CSS file of used CSS.

Laravel 5.2 - pluck() method returns array

I use laravel 7.x and I used this as a workaround:->get()->pluck('id')->toArray();

it gives back an array of ids [50,2,3] and this is the whole query I used:

   $article_tags = DB::table('tags')
    ->join('taggables', function ($join) use ($id) {
        $join->on('tags.id', '=', 'taggables.tag_id');
        $join->where([
            ['taggable_id', '=', $id],
            ['taggable_type','=','article']
        ]);
    })->select('tags.id')->get()->pluck('id')->toArray();

Difference between RUN and CMD in a Dockerfile

RUN Command: RUN command will basically, execute the default command, when we are building the image. It also will commit the image changes for next step.

There can be more than 1 RUN command, to aid in process of building a new image.

CMD Command: CMD commands will just set the default command for the new container. This will not be executed at build time.

If a docker file has more than 1 CMD commands then all of them are ignored except the last one. As this command will not execute anything but just set the default command.

ssh: connect to host github.com port 22: Connection timed out

For my case none of the suggested solutions worked so I tried to fix it myself and I got it resolved.

For me I am getting this error on my AWS EC2 UBUNTU instance, what I did to resolve it was to edit the ssh config (or add it if it does not exist).

sudo nano ~/.ssh/config

And I added the following

Host github.com
 Hostname ssh.github.com
 Port 443

Then, run the command ssh -T [email protected] to confirm if the issue is fixed.

According to this

Sometimes, firewalls refuse to allow SSH connections entirely. If using HTTPS cloning with credential caching is not an option, you can attempt to clone using an SSH connection made over the HTTPS port. Most firewall rules should allow this, but proxy servers may interfere

Hopefully this helps anyone else who's having the same issue I did.

Excel Macro : How can I get the timestamp in "yyyy-MM-dd hh:mm:ss" format?

DateTime.Now returns a value of data type Date. Date variables display dates according to the short date format and time format set on your computer.

They may be formatted as a string for display in any valid date format by the Format function as mentioned in aother answers

Format(DateTime.Now, "yyyy-MM-dd hh:mm:ss")

How to create circular ProgressBar in android?

It's easy to create this yourself

In your layout include the following ProgressBar with a specific drawable (note you should get the width from dimensions instead). The max value is important here:

<ProgressBar
    android:id="@+id/progressBar"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_width="150dp"
    android:layout_height="150dp"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:max="500"
    android:progress="0"
    android:progressDrawable="@drawable/circular" />

Now create the drawable in your resources with the following shape. Play with the radius (you can use innerRadius instead of innerRadiusRatio) and thickness values.

circular (Pre Lollipop OR API Level < 21)

   <shape
        android:innerRadiusRatio="2.3"
        android:shape="ring"
        android:thickness="3.8sp" >
        <solid android:color="@color/yourColor" />
   </shape>

circular ( >= Lollipop OR API Level >= 21)

    <shape
        android:useLevel="true"
        android:innerRadiusRatio="2.3"
        android:shape="ring"
        android:thickness="3.8sp" >
        <solid android:color="@color/yourColor" />
     </shape>

useLevel is "false" by default in API Level 21 (Lollipop) .

Start Animation

Next in your code use an ObjectAnimator to animate the progress field of the ProgessBar of your layout.

ProgressBar progressBar = (ProgressBar) view.findViewById(R.id.progressBar);
ObjectAnimator animation = ObjectAnimator.ofInt(progressBar, "progress", 0, 500); // see this max value coming back here, we animate towards that value
animation.setDuration(5000); // in milliseconds
animation.setInterpolator(new DecelerateInterpolator());
animation.start();

Stop Animation

progressBar.clearAnimation();

P.S. unlike examples above, it give smooth animation.

Simple and clean way to convert JSON string to Object in Swift

For iOS 10 & Swift 3, using Alamofire & Gloss:

Alamofire.request("http://localhost:8080/category/en").responseJSON { response in

if let data = response.data {

    if let categories = [Category].from(data: response.data) {

        self.categories = categories

        self.categoryCollectionView.reloadData()
    } else {

        print("Casting error")
    }
  } else {

    print("Data is null")
  }
}

and here is the Category class

import Gloss

struct Category: Decodable {

    let categoryId: Int?
    let name: String?
    let image: String?

    init?(json: JSON) {
        self.categoryId = "categoryId" <~~ json
        self.name = "name" <~~ json
        self.image = "image" <~~ json
    }
}

IMO, this is by far the most elegant solution.

How to convert int to date in SQL Server 2008

If your integer is timestamp in milliseconds use:

SELECT strftime("%Y-%d-%m", col_name, 'unixepoch') AS col_name

It will format milliseconds to yyyy-mm-dd string.

Converting Array to List

If you are dealing with String[] instead of int[], We can use

ArrayList<String> list = new ArrayList<>();
list.addAll(Arrays.asList(StringArray));

How do you launch the JavaScript debugger in Google Chrome?

In Chrome 8.0.552 on a Mac, you can find this under menu View/Developer/JavaScript Console ... or you can use Alt+CMD+J.

Which port(s) does XMPP use?

The official ports (TCP:5222 and TCP:5269) are listed in RFC 6120. Contrary to the claims of a previous answer, XEP-0174 does not specify a port. Thus TCP:5298 might be customary for Link-Local XMPP, but is not official.

You can use other ports than the reserved ones, though: You can make your DNS SRV record point to any machine and port you like.

File transfers (XEP-0234) are these days handled using Jingle (XEP-0166). The same goes for RTP sessions (XEP-0167). They do not specify ports, though, since Jingle negotiates the creation of the data stream between the XMPP clients, but the actual data is then transferred by other means (e.g. RTP) through that stream (i.e. not usually through the XMPP server, even though in-band transfers are possible). Beware that Jingle is comprised of several XEPs, so make sure to have a look at the whole list of XMPP extensions.

SQL update fields of one table from fields of another one

Not necessarily what you asked, but maybe using postgres inheritance might help?

CREATE TABLE A (
    ID            int,
    column1       text,
    column2       text,
    column3       text
);

CREATE TABLE B (
    column4       text
) INHERITS (A);

This avoids the need to update B.

But be sure to read all the details.

Otherwise, what you ask for is not considered a good practice - dynamic stuff such as views with SELECT * ... are discouraged (as such slight convenience might break more things than help things), and what you ask for would be equivalent for the UPDATE ... SET command.

JavaScript: client-side vs. server-side validation

The benefit of doing server side validation over client side validation is that client side validation can be bypassed/manipulated:

  • The end user could have javascript switched off
  • The data could be sent directly to your server by someone who's not even using your site, with a custom app designed to do so
  • A Javascript error on your page (caused by any number of things) could result in some, but not all, of your validation running

In short - always, always validate server-side and then consider client-side validation as an added "extra" to enhance the end user experience.

Can Selenium WebDriver open browser windows silently in the background?

If you are using Ubuntu (Gnome), one simple workaround is to install Gnome extension auto-move-window: https://extensions.gnome.org/extension/16/auto-move-windows/

Then set the browser (eg. Chrome) to another workspace (eg. Workspace 2). The browser will silently run in other workspace and not bother you anymore. You can still use Chrome in your workspace without any interruption.

How can I get the current date and time in the terminal and set a custom command in the terminal for it?

You can use date to get time and date of a day:

[pengyu@GLaDOS ~]$date
Tue Aug 27 15:01:27 CST 2013

Also hwclock would do:

[pengyu@GLaDOS ~]$hwclock
Tue 27 Aug 2013 03:01:29 PM CST  -0.516080 seconds

For customized output, you can either redirect the output of date to something like awk, or write your own program to do that.

Remember to put your own executable scripts/binary into your PATH (e.g. /usr/bin) to make it invokable anywhere.

How to echo (or print) to the js console with php

<?php  echo "<script>console.log({$yourVariable})</script>"; ?>

How do I find a default constraint using INFORMATION_SCHEMA?

Necromancing.
If you only need to check if a default-constraint exists
(default-constraint(s) may have different name in poorly-managed DBs),
use INFORMATION_SCHEMA.COLUMNS (column_default):

IF NOT EXISTS(
    SELECT * FROM INFORMATION_SCHEMA.COLUMNS
    WHERE (1=1) 
    AND TABLE_SCHEMA = 'dbo' 
    AND TABLE_NAME = 'T_VWS_PdfBibliothek' 
    AND COLUMN_NAME = 'PB_Text'
    AND COLUMN_DEFAULT IS NOT NULL  
)
BEGIN 
    EXECUTE('ALTER TABLE dbo.T_VWS_PdfBibliothek 
                ADD CONSTRAINT DF_T_VWS_PdfBibliothek_PB_Text DEFAULT (N''image'') FOR PB_Text; 
    '); 
END 

If you want to check by the constraint-name only:

-- Alternative way: 
IF OBJECT_ID('DF_CONSTRAINT_NAME', 'D') IS NOT NULL 
BEGIN
    -- constraint exists, deal with it.
END 

And last but not least, you can just create a view called
INFORMATION_SCHEMA.DEFAULT_CONSTRAINTS:

CREATE VIEW INFORMATION_SCHEMA.DEFAULT_CONSTRAINTS 
AS 
SELECT 
     DB_NAME() AS CONSTRAINT_CATALOG 
    ,csch.name AS CONSTRAINT_SCHEMA
    ,dc.name AS CONSTRAINT_NAME 
    ,DB_NAME() AS TABLE_CATALOG 
    ,sch.name AS TABLE_SCHEMA 
    ,syst.name AS TABLE_NAME 
    ,sysc.name AS COLUMN_NAME 
    ,COLUMNPROPERTY(sysc.object_id, sysc.name, 'ordinal') AS ORDINAL_POSITION 
    ,dc.type_desc AS CONSTRAINT_TYPE 
    ,dc.definition AS COLUMN_DEFAULT 

    -- ,dc.create_date 
    -- ,dc.modify_date 
FROM sys.columns AS sysc -- 46918 / 3892 with inner joins + where 
-- FROM sys.all_columns AS sysc -- 55429 / 3892 with inner joins + where 

INNER JOIN sys.tables AS syst 
    ON syst.object_id = sysc.object_id 

INNER JOIN sys.schemas AS sch
    ON sch.schema_id = syst.schema_id 

INNER JOIN sys.default_constraints AS dc 
    ON sysc.default_object_id = dc.object_id

INNER JOIN sys.schemas AS csch
    ON csch.schema_id = dc.schema_id 

WHERE (1=1) 
AND dc.is_ms_shipped = 0 

/*
WHERE (1=1) 
AND sch.name = 'dbo'
AND syst.name = 'tablename'
AND sysc.name = 'columnname'
*/

jQuery '.each' and attaching '.click' event

One solution you could use is to assign a more generalized class to any div you want the click event handler bound to.

For example:

HTML:

<body>
<div id="dog" class="selected" data-selected="false">dog</div>
<div id="cat" class="selected" data-selected="true">cat</div>
<div id="mouse" class="selected" data-selected="false">mouse</div>

<div class="dog"><img/></div>
<div class="cat"><img/></div>
<div class="mouse"><img/></div>
</body>

JS:

$( ".selected" ).each(function(index) {
    $(this).on("click", function(){
        // For the boolean value
        var boolKey = $(this).data('selected');
        // For the mammal value
        var mammalKey = $(this).attr('id'); 
    });
});

How do I show a console output/window in a forms application?

Building on Chaz's answer, in .NET 5 there is a breaking change, so two modifications are required in the project file, i.e. changing OutputType and adding DisableWinExeOutputInference. Example:

<PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net5.0-windows10.0.17763.0</TargetFramework>
    <UseWindowsForms>true</UseWindowsForms>
    <DisableWinExeOutputInference>true</DisableWinExeOutputInference>
    <Platforms>AnyCPU;x64;x86</Platforms>
</PropertyGroup>

How to ensure that there is a delay before a service is started in systemd?

Instead of editing the bringup service, add a post-start delay to the service which it depends on. Edit cassandra.service like so:

ExecStartPost=/bin/sleep 30

This way the added sleep shouldn't slow down restarts of starting services that depend on it (though does slow down its own start, maybe that's desirable?).

How to upload file using Selenium WebDriver in Java

driver.findElement(By.id("urid")).sendKeys("drive:\\path\\filename.extension");

How to remove focus from input field in jQuery?

If you have readonly attribute, blur by itself would not work. Contraption below should do the job.

$('#myInputID').removeAttr('readonly').trigger('blur').attr('readonly','readonly');

How do you completely remove Ionic and Cordova installation from mac?

Here the command to remove cordova and ionic from your machine

npm uninstall cordova ionic

Explanation of BASE terminology

It has to do with BASE: the BASE jumper kind is always Basically Available (to new relationships), in a Soft state (none of his relationship last very long) and Eventually consistent (one day he will get married).

How to run a method every X seconds

You can please try this code to call the handler every 15 seconds via onResume() and stop it when the activity is not visible, via onPause().

Handler handler = new Handler();
Runnable runnable;
int delay = 15*1000; //Delay for 15 seconds.  One second = 1000 milliseconds.


@Override
protected void onResume() {
   //start handler as activity become visible

    handler.postDelayed( runnable = new Runnable() {
        public void run() {
            //do something

            handler.postDelayed(runnable, delay);
        }
    }, delay);

    super.onResume();
}

// If onPause() is not included the threads will double up when you 
// reload the activity 

@Override
protected void onPause() {
    handler.removeCallbacks(runnable); //stop handler when activity not visible
    super.onPause();
}

The term 'ng' is not recognized as the name of a cmdlet

You can also make sure you run the Command Prompt - or whatever terminal you use - As Administrator. I am using Visual Studio Code and the ng serve command gives me that exact error when not running VS Code as admin.

java.lang.OutOfMemoryError: bitmap size exceeds VM budget - Android

I had the same problem just with switching the background images with reasonable sizes. I got better results with setting the ImageView to null before putting in a new picture.

ImageView ivBg = (ImageView) findViewById(R.id.main_backgroundImage);
ivBg.setImageDrawable(null);
ivBg.setImageDrawable(getResources().getDrawable(R.drawable.new_picture));

Imitating a blink tag with CSS3 animations

I'm going to hell for this :

=keyframes($name)
  @-webkit-keyframes #{$name}
    @content
  @-moz-keyframes #{$name}
    @content
  @-ms-keyframes #{$name}
    @content
  @keyframes #{$name}
    @content


+keyframes(blink)
  25%
    zoom: 1
    opacity: 1

  65%
    opacity: 1 

  66%
    opacity: 0

  100%
    opacity: 0

body
  font-family: sans-serif
  font-size: 4em
  background: #222
  text-align: center

  .blink
    color: rgba(#fff, 0.9)
    +animation(blink 1s 0s reverse infinite)
    +transform(translateZ(0))

.table
  display: table
  height: 5em
  width: 100%
  vertical-align: middle

  .cell
    display: table-cell
    width: 100%
    height: 100%
    vertical-align: middle

http://codepen.io/anon/pen/kaGxC (sass with bourbon)

WAMP Cannot access on local network 403 Forbidden

I got this answer from here. and its works for me

Require local

Change to

Require all granted
Order Deny,Allow
Allow from all

How to build and fill pandas dataframe from for loop?

Try this using list comprehension:

import pandas as pd

df = pd.DataFrame(
    [p, p.team, p.passing_att, p.passer_rating()] for p in game.players.passing()
)

Could not load file or assembly 'System.Net.Http.Formatting' or one of its dependencies. The system cannot find the path specified

As originally suggested in a comment by GeoMac and documented on NuGet's docs the following worked for me when none of the other answers worked:

Tools / NuGet Package Manager / Package Manager Console

Update-Package -ProjectName MyProjectName -reinstall

Set the default value in dropdownlist using jQuery

One line of jQuery does it all!

$("#myCombobox option[text='it\'s me']").attr("selected","selected"); 

Jquery UI tooltip does not support html content

another solution will be to grab the text inside the title tag & then use .html() method of jQuery to construct the content of the tooltip.

$(function() {
  $(document).tooltip({
    position: {
      using: function(position, feedback) {
        $(this).css(position);
        var txt = $(this).text();
        $(this).html(txt);
        $("<div>")
          .addClass("arrow")
          .addClass(feedback.vertical)
          .addClass(feedback.horizontal)
          .appendTo(this);
      }
    }
  });
});

Example: http://jsfiddle.net/hamzeen/0qwxfgjo/

MacOSX homebrew mysql root password

Terminal 1:

$ mysql_safe

Terminal 2:

$ mysql -u root
mysql> UPDATE mysql.user SET Password=PASSWORD('new-password') WHERE User='root';
mysql> FLUSH PRIVILEGES;
mysql> quit

Get last key-value pair in PHP array

You can use end to advance the internal pointer to the end or array_slice to get an array only containing the last element:

$last = end($arr);
$last = current(array_slice($arr, -1));

Getting a list of values from a list of dicts

For a very simple case like this, a comprehension, as in Ismail Badawi's answer is definitely the way to go.

But when things get more complicated, and you need to start writing multi-clause or nested comprehensions with complex expressions in them, it's worth looking into other alternatives. There are a few different (quasi-)standard ways to specify XPath-style searches on nested dict-and-list structures, such as JSONPath, DPath, and KVC. And there are nice libraries on PyPI for them.

Here's an example with the library named dpath, showing how it can simplify something just a bit more complicated:

>>> dd = {
...     'fruits': [{'value': 'apple', 'blah': 2}, {'value': 'banana', 'blah': 3}],
...     'vehicles': [{'value': 'cars', 'blah':4}]}

>>> {key: [{'value': d['value']} for d in value] for key, value in dd.items()}
{'fruits': [{'value': 'apple'}, {'value': 'banana'}],
 'vehicles': [{'value': 'cars'}]}

>>> dpath.util.search(dd, '*/*/value')
{'fruits': [{'value': 'apple'}, {'value': 'banana'}],
 'vehicles': [{'value': 'cars'}]}

Or, using jsonpath-ng:

>>> [d['value'] for key, value in dd.items() for d in value]
['apple', 'banana', 'cars']
>>> [m.value for m in jsonpath_ng.parse('*.[*].value').find(dd)]
['apple', 'banana', 'cars']

This one may not look quite as simple at first glance, because find returns match objects, which include all kinds of things besides just the matched value, such as a path directly to each item. But for more complex expressions, being able to specify a path like '*.[*].value' instead of a comprehension clause for each * can make a big difference. Plus, JSONPath is a language-agnostic specification, and there are even online testers that can be very handy for debugging.

RestSharp JSON Parameter Posting

Hope this will help someone. It worked for me -

RestClient client = new RestClient("http://www.example.com/");
RestRequest request = new RestRequest("login", Method.POST);
request.AddHeader("Accept", "application/json");
var body = new
{
    Host = "host_environment",
    Username = "UserID",
    Password = "Password"
};
request.AddJsonBody(body);

var response = client.Execute(request).Content;

Various ways to remove local Git changes

As with everything in git there are multiple ways of doing it. The two commands you used are one way of doing it. Another thing you could have done is simply stash them with git stash -u. The -u makes sure that newly added files (untracked) are also included.

The handy thing about git stash -u is that

  1. it is probably the simplest (only?) single command to accomplish your goal
  2. if you change your mind afterwards you get all your work back with git stash pop (it's like deleting an email in gmail where you can just undo if you change your mind afterwards)

As of your other question git reset --hard won't remove the untracked files so you would still need the git clean -f. But a git stash -u might be the most convenient.

How do I horizontally center a span element inside a div

Applying inline-block to the element that is to be centered and applying text-align:center to the parent block did the trick for me.

Works even on <span> tags.