Programs & Examples On #Runloop

How to fix Error: this class is not key value coding-compliant for the key tableView.'

You have your storyboard set up to expect an outlet called tableView but the actual outlet name is myTableView.

If you delete the connection in the storyboard and reconnect to the right variable name, it should fix the problem.

UICollectionView - dynamic cell height?

Seems like it's quite a popular question, so I will try to make my humble contribution.


The code below is Swift 4 solution for no-storyboard setup. It utilizes some approaches from previous answers, therefore it prevents Auto Layout warning caused on device rotation.

I am sorry if code samples are a bit long. I want to provide an "easy-to-use" solution fully hosted by StackOverflow. If you have any suggestions to the post - please, share the idea and I will update it accordingly.

The setup:

Two classes: ViewController.swift and MultilineLabelCell.swift - Cell containing single UILabel.

MultilineLabelCell.swift

import UIKit

class MultilineLabelCell: UICollectionViewCell {
    static let reuseId = "MultilineLabelCellReuseId"

    private let label: UILabel = UILabel(frame: .zero)

    override init(frame: CGRect) {
        super.init(frame: frame)

        layer.borderColor = UIColor.red.cgColor
        layer.borderWidth = 1.0

        label.numberOfLines = 0
        label.lineBreakMode = .byWordWrapping

        let labelInset = UIEdgeInsets(top: 10, left: 10, bottom: -10, right: -10)
        contentView.addSubview(label)
        label.translatesAutoresizingMaskIntoConstraints = false
        label.topAnchor.constraint(equalTo: contentView.layoutMarginsGuide.topAnchor, constant: labelInset.top).isActive = true
        label.leadingAnchor.constraint(equalTo: contentView.layoutMarginsGuide.leadingAnchor, constant: labelInset.left).isActive = true
        label.trailingAnchor.constraint(equalTo: contentView.layoutMarginsGuide.trailingAnchor, constant: labelInset.right).isActive = true
        label.bottomAnchor.constraint(equalTo: contentView.layoutMarginsGuide.bottomAnchor, constant: labelInset.bottom).isActive = true

        label.layer.borderColor = UIColor.black.cgColor
        label.layer.borderWidth = 1.0
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("Storyboards are quicker, easier, more seductive. Not stronger then Code.")
    }

    func configure(text: String?) {
        label.text = text
    }

    override func preferredLayoutAttributesFitting(_ layoutAttributes: UICollectionViewLayoutAttributes) -> UICollectionViewLayoutAttributes {
        label.preferredMaxLayoutWidth = layoutAttributes.size.width - contentView.layoutMargins.left - contentView.layoutMargins.left
        layoutAttributes.bounds.size.height = systemLayoutSizeFitting(UIView.layoutFittingCompressedSize).height
        return layoutAttributes
    }
}

ViewController.swift

import UIKit

let samuelQuotes = [
    "Samuel says", 
    "Add different length strings here for better testing"
]

class ViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
    private(set) var collectionView: UICollectionView

    // Initializers
    init() {
        // Create new `UICollectionView` and set `UICollectionViewFlowLayout` as its layout
        collectionView = UICollectionView(frame: .zero, collectionViewLayout: UICollectionViewFlowLayout())
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder aDecoder: NSCoder) {
        // Create new `UICollectionView` and set `UICollectionViewFlowLayout` as its layout
        collectionView = UICollectionView(frame: .zero, collectionViewLayout: UICollectionViewFlowLayout())
        super.init(coder: aDecoder)
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        title = "Dynamic size sample"

        // Register Cells
        collectionView.register(MultilineLabelCell.self, forCellWithReuseIdentifier: MultilineLabelCell.reuseId)

        // Add `coolectionView` to display hierarchy and setup its appearance
        view.addSubview(collectionView)
        collectionView.backgroundColor = .white
        collectionView.contentInsetAdjustmentBehavior = .always
        collectionView.contentInset = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)

        // Setup Autolayout constraints
        collectionView.translatesAutoresizingMaskIntoConstraints = false
        collectionView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0).isActive = true
        collectionView.leftAnchor.constraint(equalTo: view.leftAnchor, constant: 0).isActive = true
        collectionView.topAnchor.constraint(equalTo: view.topAnchor, constant: 0).isActive = true
        collectionView.rightAnchor.constraint(equalTo: view.rightAnchor, constant: 0).isActive = true

        // Setup `dataSource` and `delegate`
        collectionView.dataSource = self
        collectionView.delegate = self

        (collectionView.collectionViewLayout as! UICollectionViewFlowLayout).estimatedItemSize = UICollectionViewFlowLayout.automaticSize
        (collectionView.collectionViewLayout as! UICollectionViewFlowLayout).sectionInsetReference = .fromLayoutMargins
    }

    // MARK: - UICollectionViewDataSource -
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: MultilineLabelCell.reuseId, for: indexPath) as! MultilineLabelCell
        cell.configure(text: samuelQuotes[indexPath.row])
        return cell
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return samuelQuotes.count
    }

    // MARK: - UICollectionViewDelegateFlowLayout -
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        let sectionInset = (collectionViewLayout as! UICollectionViewFlowLayout).sectionInset
        let referenceHeight: CGFloat = 100 // Approximate height of your cell
        let referenceWidth = collectionView.safeAreaLayoutGuide.layoutFrame.width
            - sectionInset.left
            - sectionInset.right
            - collectionView.contentInset.left
            - collectionView.contentInset.right
        return CGSize(width: referenceWidth, height: referenceHeight)
    }
}

To run this sample create new Xcode project, create corresponding files and replace AppDelegate contents with the following code:

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?
    var navigationController: UINavigationController?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        window = UIWindow(frame: UIScreen.main.bounds)

        if let window = window {
            let vc = ViewController()
            navigationController = UINavigationController(rootViewController: vc)
            window.rootViewController = navigationController
            window.makeKeyAndVisible()
        }

        return true
    }
}

libc++abi.dylib: terminating with uncaught exception of type NSException (lldb)

For me, the problem was in my IBAction with a UIButton.

When you Ctrl+Drag to create an IBAction from a UIButton, make sure to select "UIButton" from the Type dropdown. The default selection of AnyObject causes the app to crash when you tap on the UIButton.

enter image description here

symbol(s) not found for architecture i386

Make sure that the missing framework is actually listed under "Target/Build Phases/Link Binary With Libraries" if not just add it. As mentioned before it usually indicates a missing framework.

In my project there were two identical framework listed, when I removed one of them I had this error, because it also removed it form the the "Link Binary With Libraries" list. I added back and the problem disappeared (and I still have two frameworks listed)

XAMPP: Couldn't start Apache (Windows 10)

You can change the port of Apache:

  1. Go to C:\xampp\apache\conf\httpd.
  2. Find by combination Ctrl+F line #Listen 12.34.56.78:80 and change the 80 to any you like for example 81
  3. The same with Listen 80 change to 81
  4. The same with ServerName localhost:80 change to 81.
  5. Go to C:\xampp\apache\conf\extra\httpd-vhosts and change 80 to 81

NameVirtualHost *:80 here

VirtualHost *:80 and here (two times)

  1. Restart Apache

To enter your web page, type: http://localhost:81/index.html

TypeScript: correct way to do string equality?

If you know x and y are both strings, using === is not strictly necessary, but is still good practice.

Assuming both variables actually are strings, both operators will function identically. However, TS often allows you to pass an object that meets all the requirements of string rather than an actual string, which may complicate things.

Given the possibility of confusion or changes in the future, your linter is probably correct in demanding ===. Just go with that.

ab load testing

Load testing your API by using just ab is not enough. However, I think it's a great tool to give you a basic idea how your site is performant.

If you want to use the ab command in to test multiple API endpoints, with different data, all at the same time in background, you need to use "nohup" command. It runs any command even when you close the terminal.

I wrote a simple script that automates the whole process, feel free to use it: http://blog.ikvasnica.com/entry/load-test-multiple-api-endpoints-concurrently-use-this-simple-shell-script

Stripping everything but alphanumeric chars from a string in Python

I just timed some functions out of curiosity. In these tests I'm removing non-alphanumeric characters from the string string.printable (part of the built-in string module). The use of compiled '[\W_]+' and pattern.sub('', str) was found to be fastest.

$ python -m timeit -s \
     "import string" \
     "''.join(ch for ch in string.printable if ch.isalnum())" 
10000 loops, best of 3: 57.6 usec per loop

$ python -m timeit -s \
    "import string" \
    "filter(str.isalnum, string.printable)"                 
10000 loops, best of 3: 37.9 usec per loop

$ python -m timeit -s \
    "import re, string" \
    "re.sub('[\W_]', '', string.printable)"
10000 loops, best of 3: 27.5 usec per loop

$ python -m timeit -s \
    "import re, string" \
    "re.sub('[\W_]+', '', string.printable)"                
100000 loops, best of 3: 15 usec per loop

$ python -m timeit -s \
    "import re, string; pattern = re.compile('[\W_]+')" \
    "pattern.sub('', string.printable)" 
100000 loops, best of 3: 11.2 usec per loop

Splitting strings using a delimiter in python

So, your input is 'dan|warrior|54' and you want "warrior". You do this like so:

>>> dan = 'dan|warrior|54'
>>> dan.split('|')[1]
"warrior"

Passing a callback function to another class

Delegate is just the base class so you can't use it like that. You could do something like this though:

public void DoRequest(string request, Action<string> callback)
{
     // do stuff....
     callback("asdf");
}

Force file download with php using header()

Here is a snippet from me in testing... obviously passing via get to the script may not be the best... should post or just send an id and grab guid from db... anyhow.. this worked. I take the URL and convert it to a path.

// Initialize a file URL to the variable
$file = $_GET['url'];
$file = str_replace(Polepluginforrvms_Plugin::$install_url, $DOC_ROOT.'/pole-permitter/', $file );

$quoted = sprintf('"%s"', addcslashes(basename($file), '"\\'));
$size   = filesize($file);

header( "Content-type: application/octet-stream" );
header( "Content-Disposition: attachment; filename={$quoted}" );
header( "Content-length: " . $size );
header( "Pragma: no-cache" );
header( "Expires: 0" );
readfile( "{$file}" );

Importing Maven project into Eclipse

I find the m2eclipse plugin to be more useful. This provides nice tools like the POM editor and creating a Maven project from within Eclipse.

CSS Box Shadow - Top and Bottom Only

essentially the shadow is the box shape just offset behind the actual box. in order to hide portions of the shadow, you need to create additional divs and set their z-index above the shadowed box so that the shadow is not visible.

If you'd like to have extremely specific control over your shadows, build them as images and created container divs with the right amount of padding and margins.. then use the png fix to make sure the shadows render properly in all browsers

Printing column separated by comma using Awk command line

If your only requirement is to print the third field of every line, with each field delimited by a comma, you can use cut:

cut -d, -f3 file
  • -d, sets the delimiter to a comma
  • -f3 specifies that only the third field is to be printed

How to send an email with Gmail as provider using Python?

Not directly related but still worth pointing out is that my package tries to make sending gmail messages really quick and painless. It also tries to maintain a list of errors and tries to point to the solution immediately.

It would literally only need this code to do exactly what you wrote:

import yagmail
yag = yagmail.SMTP('[email protected]')
yag.send('[email protected]', 'Why,Oh why!')

Or a one liner:

yagmail.SMTP('[email protected]').send('[email protected]', 'Why,Oh why!')

For the package/installation please look at git or pip, available for both Python 2 and 3.

How do I specify "close existing connections" in sql script

According to the ALTER DATABASE SET documentation, there is still a possibility that after setting a database to SINGLE_USER mode you won't be able to access that database:

Before you set the database to SINGLE_USER, verify the AUTO_UPDATE_STATISTICS_ASYNC option is set to OFF. When set to ON, the background thread used to update statistics takes a connection against the database, and you will be unable to access the database in single-user mode.

So, a complete script to drop the database with existing connections may look like this:

DECLARE @dbId int
DECLARE @isStatAsyncOn bit
DECLARE @jobId int
DECLARE @sqlString nvarchar(500)

SELECT @dbId = database_id,
       @isStatAsyncOn = is_auto_update_stats_async_on
FROM sys.databases
WHERE name = 'db_name'

IF @isStatAsyncOn = 1
BEGIN
    ALTER DATABASE [db_name] SET  AUTO_UPDATE_STATISTICS_ASYNC OFF

    -- kill running jobs
    DECLARE jobsCursor CURSOR FOR
    SELECT job_id
    FROM sys.dm_exec_background_job_queue
    WHERE database_id = @dbId

    OPEN jobsCursor

    FETCH NEXT FROM jobsCursor INTO @jobId
    WHILE @@FETCH_STATUS = 0
    BEGIN
        set @sqlString = 'KILL STATS JOB ' + STR(@jobId)
        EXECUTE sp_executesql @sqlString
        FETCH NEXT FROM jobsCursor INTO @jobId
    END

    CLOSE jobsCursor
    DEALLOCATE jobsCursor
END

ALTER DATABASE [db_name] SET  SINGLE_USER WITH ROLLBACK IMMEDIATE

DROP DATABASE [db_name]

TSQL PIVOT MULTIPLE COLUMNS

Since you want to pivot multiple columns of data, I would first suggest unpivoting the result, score and grade columns so you don't have multiple columns but you will have multiple rows.

Depending on your version of SQL Server you can use the UNPIVOT function or CROSS APPLY. The syntax to unpivot the data will be similar to:

select ratio, col, value
from GRAND_TOTALS
cross apply
(
  select 'result', cast(result as varchar(10)) union all
  select 'score', cast(score as varchar(10)) union all
  select 'grade', grade
) c(col, value)

See SQL Fiddle with Demo. Once the data has been unpivoted, then you can apply the PIVOT function:

select ratio = col,
  [current ratio], [gearing ratio], [performance ratio], total
from
(
  select ratio, col, value
  from GRAND_TOTALS
  cross apply
  (
    select 'result', cast(result as varchar(10)) union all
    select 'score', cast(score as varchar(10)) union all
    select 'grade', grade
  ) c(col, value)
) d
pivot
(
  max(value)
  for ratio in ([current ratio], [gearing ratio], [performance ratio], total)
) piv;

See SQL Fiddle with Demo. This will give you the result:

|  RATIO | CURRENT RATIO | GEARING RATIO | PERFORMANCE RATIO |     TOTAL |
|--------|---------------|---------------|-------------------|-----------|
|  grade |          Good |          Good |      Satisfactory |      Good |
| result |       1.29400 |       0.33840 |           0.04270 |    (null) |
|  score |      60.00000 |      70.00000 |          50.00000 | 180.00000 |

How to delete all files and folders in a folder by cmd call

del .\*

This Command delete all files & folders from current navigation in your command line.

Python: convert string to byte array

Depending on your needs, this can be one step or two steps

1. use encode() to convert string to bytes, immutable
2. use bytearray() to convert bytes to bytearray, mutable

s="ABCD"
encoded=s.encode('utf-8')
array=bytearray(encoded)

The following validation is done in Python 3.7

>>> s="ABCD"
>>> encoded=s.encode('utf-8')
>>> encoded
b'ABCD'
>>> array=bytearray(encoded)
>>> array
bytearray(b'ABCD')

JavaScript property access: dot notation vs. brackets?

Dot notation does not work with some keywords (like new and class) in internet explorer 8.

I had this code:

//app.users is a hash
app.users.new = {
  // some code
}

And this triggers the dreaded "expected indentifier" (at least on IE8 on windows xp, I havn't tried other environments). The simple fix for that is to switch to bracket notation:

app.users['new'] = {
  // some code
}

How can I use threading in Python?

I would like to contribute with a simple example and the explanations I've found useful when I had to tackle this problem myself.

In this answer you will find some information about Python's GIL (global interpreter lock) and a simple day-to-day example written using multiprocessing.dummy plus some simple benchmarks.

Global Interpreter Lock (GIL)

Python doesn't allow multi-threading in the truest sense of the word. It has a multi-threading package, but if you want to multi-thread to speed your code up, then it's usually not a good idea to use it.

Python has a construct called the global interpreter lock (GIL). The GIL makes sure that only one of your 'threads' can execute at any one time. A thread acquires the GIL, does a little work, then passes the GIL onto the next thread.

This happens very quickly so to the human eye it may seem like your threads are executing in parallel, but they are really just taking turns using the same CPU core.

All this GIL passing adds overhead to execution. This means that if you want to make your code run faster then using the threading package often isn't a good idea.

There are reasons to use Python's threading package. If you want to run some things simultaneously, and efficiency is not a concern, then it's totally fine and convenient. Or if you are running code that needs to wait for something (like some I/O) then it could make a lot of sense. But the threading library won't let you use extra CPU cores.

Multi-threading can be outsourced to the operating system (by doing multi-processing), and some external application that calls your Python code (for example, Spark or Hadoop), or some code that your Python code calls (for example: you could have your Python code call a C function that does the expensive multi-threaded stuff).

Why This Matters

Because lots of people spend a lot of time trying to find bottlenecks in their fancy Python multi-threaded code before they learn what the GIL is.

Once this information is clear, here's my code:

#!/bin/python
from multiprocessing.dummy import Pool
from subprocess import PIPE,Popen
import time
import os

# In the variable pool_size we define the "parallelness".
# For CPU-bound tasks, it doesn't make sense to create more Pool processes
# than you have cores to run them on.
#
# On the other hand, if you are using I/O-bound tasks, it may make sense
# to create a quite a few more Pool processes than cores, since the processes
# will probably spend most their time blocked (waiting for I/O to complete).
pool_size = 8

def do_ping(ip):
    if os.name == 'nt':
        print ("Using Windows Ping to " + ip)
        proc = Popen(['ping', ip], stdout=PIPE)
        return proc.communicate()[0]
    else:
        print ("Using Linux / Unix Ping to " + ip)
        proc = Popen(['ping', ip, '-c', '4'], stdout=PIPE)
        return proc.communicate()[0]


os.system('cls' if os.name=='nt' else 'clear')
print ("Running using threads\n")
start_time = time.time()
pool = Pool(pool_size)
website_names = ["www.google.com","www.facebook.com","www.pinterest.com","www.microsoft.com"]
result = {}
for website_name in website_names:
    result[website_name] = pool.apply_async(do_ping, args=(website_name,))
pool.close()
pool.join()
print ("\n--- Execution took {} seconds ---".format((time.time() - start_time)))

# Now we do the same without threading, just to compare time
print ("\nRunning NOT using threads\n")
start_time = time.time()
for website_name in website_names:
    do_ping(website_name)
print ("\n--- Execution took {} seconds ---".format((time.time() - start_time)))

# Here's one way to print the final output from the threads
output = {}
for key, value in result.items():
    output[key] = value.get()
print ("\nOutput aggregated in a Dictionary:")
print (output)
print ("\n")

print ("\nPretty printed output: ")
for key, value in output.items():
    print (key + "\n")
    print (value)

How do JavaScript closures work?

Every function in JavaScript maintains a link to its outer lexical environment. A lexical environment is a map of all the names (eg. variables, parameters) within a scope, with their values.

So, whenever you see the function keyword, code inside that function has access to variables declared outside the function.

_x000D_
_x000D_
function foo(x) {_x000D_
  var tmp = 3;_x000D_
_x000D_
  function bar(y) {_x000D_
    console.log(x + y + (++tmp)); // will log 16_x000D_
  }_x000D_
_x000D_
  bar(10);_x000D_
}_x000D_
_x000D_
foo(2);
_x000D_
_x000D_
_x000D_

This will log 16 because function bar closes over the parameter x and the variable tmp, both of which exist in the lexical environment of outer function foo.

Function bar, together with its link with the lexical environment of function foo is a closure.

A function doesn't have to return in order to create a closure. Simply by virtue of its declaration, every function closes over its enclosing lexical environment, forming a closure.

_x000D_
_x000D_
function foo(x) {_x000D_
  var tmp = 3;_x000D_
_x000D_
  return function (y) {_x000D_
    console.log(x + y + (++tmp)); // will also log 16_x000D_
  }_x000D_
}_x000D_
_x000D_
var bar = foo(2);_x000D_
bar(10); // 16_x000D_
bar(10); // 17
_x000D_
_x000D_
_x000D_

The above function will also log 16, because the code inside bar can still refer to argument x and variable tmp, even though they are no longer directly in scope.

However, since tmp is still hanging around inside bar's closure, it is available to be incremented. It will be incremented each time you call bar.

The simplest example of a closure is this:

_x000D_
_x000D_
var a = 10;_x000D_
_x000D_
function test() {_x000D_
  console.log(a); // will output 10_x000D_
  console.log(b); // will output 6_x000D_
}_x000D_
var b = 6;_x000D_
test();
_x000D_
_x000D_
_x000D_

When a JavaScript function is invoked, a new execution context ec is created. Together with the function arguments and the target object, this execution context also receives a link to the lexical environment of the calling execution context, meaning the variables declared in the outer lexical environment (in the above example, both a and b) are available from ec.

Every function creates a closure because every function has a link to its outer lexical environment.

Note that variables themselves are visible from within a closure, not copies.

Iterating over every property of an object in javascript using Prototype?

There's no need for Prototype here: JavaScript has for..in loops. If you're not sure that no one messed with Object.prototype, check hasOwnProperty() as well, ie

for(var prop in obj) {
    if(obj.hasOwnProperty(prop))
        doSomethingWith(obj[prop]);
}

T-SQL loop over query results

My prefer solution is Microsoft KB 111401 http://support.microsoft.com/kb/111401.

The link refers to 3 examples:

This article describes various methods that you can use to simulate a cursor-like FETCH-NEXT logic in a stored procedure, trigger, or Transact-SQL batch.

/*********** example 1 ***********/ 

declare @au_id char( 11 )

set rowcount 0
select * into #mytemp from authors

set rowcount 1

select @au_id = au_id from #mytemp

while @@rowcount <> 0
begin
    set rowcount 0
    select * from #mytemp where au_id = @au_id
    delete #mytemp where au_id = @au_id

    set rowcount 1
    select @au_id = au_id from #mytemp
end
set rowcount 0



/********** example 2 **********/ 

declare @au_id char( 11 )

select @au_id = min( au_id ) from authors

while @au_id is not null
begin
    select * from authors where au_id = @au_id
    select @au_id = min( au_id ) from authors where au_id > @au_id
end



/********** example 3 **********/ 

set rowcount 0
select NULL mykey, * into #mytemp from authors

set rowcount 1
update #mytemp set mykey = 1

while @@rowcount > 0
begin
    set rowcount 0
    select * from #mytemp where mykey = 1
    delete #mytemp where mykey = 1
    set rowcount 1
    update #mytemp set mykey = 1
end
set rowcount 0

How should I copy Strings in Java?

Your second version is less efficient because it creates an extra string object when there is simply no need to do so.

Immutability means that your first version behaves the way you expect and is thus the approach to be preferred.

Rails 3 check if attribute changed

This is how I solved the problem of checking for changes in multiple attributes.

attrs = ["street1", "street2", "city", "state", "zipcode"]

if (@user.changed & attrs).any?
  then do something....
end

The changed method returns an array of the attributes changed for that object.

Both @user.changed and attrs are arrays so I can get the intersection (see ary & other ary method). The result of the intersection is an array. By calling any? on the array, I get true if there is at least one intersection.

Also very useful, the changed_attributes method returns a hash of the attributes with their original values and the changes returns a hash of the attributes with their original and new values (in an array).

You can check APIDock for which versions supported these methods.

http://apidock.com/rails/ActiveModel/Dirty

mysql_fetch_array()/mysql_fetch_assoc()/mysql_fetch_row()/mysql_num_rows etc... expects parameter 1 to be resource

Traditionally PHP has been tolerant to bad practice and failures in code, which makes debugging quite hard. The problem in this specific case is that both mysqli and PDO by default don't tell you, when a query failed and just return FALSE. (I will not talk about the depricated mysql extention. The support for prepared statements is reason anough to switch either to PDO or mysqli.) But you can change the default behavior of PHP to always throw exceptions when a query fails.

For PDO: Use $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

error_reporting(E_ALL);

$pdo = new PDO("mysql:host=localhost;dbname=test", "test","");
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$result = $pdo->query('select emal from users');
$data = $result->fetchAll();

This will show you the following:

Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[42S22]: Column not found: 1054 Unknown column 'emal' in 'field list'' in E:\htdocs\test\mysql_errors\pdo.php on line 8

PDOException: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'emal' in 'field list' in E:\htdocs\test\mysql_errors\pdo.php on line 8

As you see, it tells you exactly, what is wrong with the query, and where to fix it in your code.

Without $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); you will get

Fatal error: Call to a member function fetchAll() on boolean in E:\htdocs\test\mysql_errors\pdo.php on line 9

For mysqli: Use mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

error_reporting(E_ALL);

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli('localhost', 'test', '', 'test');

$result = $mysqli->query('select emal from users');
$data = $result->fetch_all();

You will get

Fatal error: Uncaught exception 'mysqli_sql_exception' with message 'Unknown column 'emal' in 'field list'' in E:\htdocs\test\mysql_errors\mysqli.php on line 8

mysqli_sql_exception: Unknown column 'emal' in 'field list' in E:\htdocs\test\mysql_errors\mysqli.php on line 8

Without mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT); you only get

Fatal error: Call to a member function fetch_all() on boolean in E:\htdocs\test\mysql_errors\mysqli.php on line 10

Of course, you could manually check the MySQL errors. But I would go crazy if I had to do that every time I made a typo - or worse - every time I want to query the database.

sql how to cast a select query

If you're using SQL (which you didn't say):

select cast(column as varchar(200)) from table 

You can use it in any statement, for example:

select value where othervalue in( select cast(column as varchar(200)) from table)
from othertable

If you want to do a join query, the answer is here already in another post :)

Simple way to convert datarow array to datatable

Why not iterate through your DataRow array and add (using DataRow.ImportRow, if necessary, to get a copy of the DataRow), something like:

foreach (DataRow row in rowArray) {
   dataTable.ImportRow(row);
}

Make sure your dataTable has the same schema as the DataRows in your DataRow array.

Check cell for a specific letter or set of letters

Some options without REGEXMATCH, since you might want to be case insensitive and not want say blast or ablative to trigger a YES. Using comma as the delimiter, as in the OP, and for the moment ignoring the IF condition:

First very similar to @user1598086's answer:

=FIND("bla",A1)

Is case sensitive but returns #VALUE! rather than NO and a number rather than YES (both of which can however be changed to NO/YES respectively).

=SEARCH("bla",A1)  

Case insensitive, so treats Black and black equally. Returns as above.

The former (for the latter equivalent) to indicate whether bla present after the first three characters in A1:

=FIND("bla",A1,4)  

Returns a number for blazer, black but #VALUE! for blazer, blue.

To find Bla only when a complete word on its own (ie between spaces - not at the start or end of a 'sentence'):

=SEARCH(" Bla ",A1) 

Since the return in all cases above is either a number ("found", so YES preferred) or #VALUE! we can use ISERROR to test for #VALUE! within an IF formula, for instance taking the first example above:

 =if(iserror(FIND("bla",A1)),"NO","YES")  

Longer than the regexmatch but the components are easily adjustable.

How to print multiple variable lines in Java

System.out.println("First Name: " + firstname);
System.out.println("Last Name: " + lastname);

or

System.out.println(String.format("First Name: %s", firstname));
System.out.println(String.format("Last Name: %s", lastname));

MVC: How to Return a String as JSON

The issue, I believe, is that the Json action result is intended to take an object (your model) and create an HTTP response with content as the JSON-formatted data from your model object.

What you are passing to the controller's Json method, though, is a JSON-formatted string object, so it is "serializing" the string object to JSON, which is why the content of the HTTP response is surrounded by double-quotes (I'm assuming that is the problem).

I think you can look into using the Content action result as an alternative to the Json action result, since you essentially already have the raw content for the HTTP response available.

return this.Content(returntext, "application/json");
// not sure off-hand if you should also specify "charset=utf-8" here, 
//  or if that is done automatically

Another alternative would be to deserialize the JSON result from the service into an object and then pass that object to the controller's Json method, but the disadvantage there is that you would be de-serializing and then re-serializing the data, which may be unnecessary for your purposes.

How to prevent IFRAME from redirecting top-level window

I know it has been a long time since question was done but here is my improved version it will wait 500ms for any subsequent call only when the iframe is loaded.

<script type="text/javasript">
var prevent_bust = false ;
    var from_loading_204 = false;
    var frame_loading = false;
    var prevent_bust_timer = 0;
    var  primer = true;
    window.onbeforeunload = function(event) {
        prevent_bust = !from_loading_204 && frame_loading;
        if(from_loading_204)from_loading_204 = false;
        if(prevent_bust){
            prevent_bust_timer=500;
        }
    }
    function frameLoad(){
        if(!primer){
            from_loading_204 = true;
            window.top.location = '/?204';
            prevent_bust = false;
            frame_loading = true;
            prevent_bust_timer=1000;
        }else{
            primer = false;
        }
    }
    setInterval(function() {  
        if (prevent_bust_timer>0) {  
            if(prevent_bust){
                from_loading_204 = true;
                window.top.location = '/?204';
                prevent_bust = false;
            }else if(prevent_bust_timer == 1){
                frame_loading = false;
                prevent_bust = false;
                from_loading_204 = false;
                prevent_bust_timer == 0;
            }



        }
        prevent_bust_timer--;
        if(prevent_bust_timer==-100) {
            prevent_bust_timer = 0;
        }
    }, 1);
</script>

and onload="frameLoad()" and onreadystatechange="frameLoad();" must be added to the frame or iframe.

How to pass an array to a function in VBA?

This seems unnecessary, but VBA is a strange place. If you declare an array variable, then set it using Array() then pass the variable into your function, VBA will be happy.

Sub test()
    Dim fString As String
    Dim arr() As Variant
    arr = Array("foo", "bar")
    fString = processArr(arr)
End Sub

Also your function processArr() could be written as:

Function processArr(arr() As Variant) As String
    processArr = Replace(Join(arr()), " ", "")
End Function

If you are into the whole brevity thing.

OpenCV NoneType object has no attribute shape

You probably get the error because your video path may be wrong in a way. Be sure your path is completely correct.

System.Windows.Markup.XamlParseException' occurred in PresentationFramework.dll?

Problem solved! I'm using Ctrl + Alt + E to open Exception Window, and I checked all throw checkbox. So the debuger can stop at the exactly the error code.

Executing a stored procedure within a stored procedure

Thats how it works stored procedures run in order, you don't need begin just something like

exec dbo.sp1
exec dbo.sp2

How can I inspect the file system of a failed `docker build`?

Everytime docker successfully executes a RUN command from a Dockerfile, a new layer in the image filesystem is committed. Conveniently you can use those layers ids as images to start a new container.

Take the following Dockerfile:

FROM busybox
RUN echo 'foo' > /tmp/foo.txt
RUN echo 'bar' >> /tmp/foo.txt

and build it:

$ docker build -t so-2622957 .
Sending build context to Docker daemon 47.62 kB
Step 1/3 : FROM busybox
 ---> 00f017a8c2a6
Step 2/3 : RUN echo 'foo' > /tmp/foo.txt
 ---> Running in 4dbd01ebf27f
 ---> 044e1532c690
Removing intermediate container 4dbd01ebf27f
Step 3/3 : RUN echo 'bar' >> /tmp/foo.txt
 ---> Running in 74d81cb9d2b1
 ---> 5bd8172529c1
Removing intermediate container 74d81cb9d2b1
Successfully built 5bd8172529c1

You can now start a new container from 00f017a8c2a6, 044e1532c690 and 5bd8172529c1:

$ docker run --rm 00f017a8c2a6 cat /tmp/foo.txt
cat: /tmp/foo.txt: No such file or directory

$ docker run --rm 044e1532c690 cat /tmp/foo.txt
foo

$ docker run --rm 5bd8172529c1 cat /tmp/foo.txt
foo
bar

of course you might want to start a shell to explore the filesystem and try out commands:

$ docker run --rm -it 044e1532c690 sh      
/ # ls -l /tmp
total 4
-rw-r--r--    1 root     root             4 Mar  9 19:09 foo.txt
/ # cat /tmp/foo.txt 
foo

When one of the Dockerfile command fails, what you need to do is to look for the id of the preceding layer and run a shell in a container created from that id:

docker run --rm -it <id_last_working_layer> bash -il

Once in the container:

  • try the command that failed, and reproduce the issue
  • then fix the command and test it
  • finally update your Dockerfile with the fixed command

If you really need to experiment in the actual layer that failed instead of working from the last working layer, see Drew's answer.

How to get everything after last slash in a URL?

One more (idio(ma)tic) way:

URL.split("/")[-1]

WooCommerce - get category for product page

Thanks Box. I'm using MyStile Theme and I needed to display the product category name in my search result page. I added this function to my child theme functions.php

Hope it helps others.

/* Post Meta */


if (!function_exists( 'woo_post_meta')) {
    function woo_post_meta( ) {
        global $woo_options;
        global $post;

        $terms = get_the_terms( $post->ID, 'product_cat' );
        foreach ($terms as $term) {
            $product_cat = $term->name;
            break;
        }

?>
<aside class="post-meta">
    <ul>
        <li class="post-category">
            <?php the_category( ', ', $post->ID) ?>
                        <?php echo $product_cat; ?>

        </li>
        <?php the_tags( '<li class="tags">', ', ', '</li>' ); ?>
        <?php if ( isset( $woo_options['woo_post_content'] ) && $woo_options['woo_post_content'] == 'excerpt' ) { ?>
            <li class="comments"><?php comments_popup_link( __( 'Leave a comment', 'woothemes' ), __( '1 Comment', 'woothemes' ), __( '% Comments', 'woothemes' ) ); ?></li>
        <?php } ?>
        <?php edit_post_link( __( 'Edit', 'woothemes' ), '<li class="edit">', '</li>' ); ?>
    </ul>
</aside>
<?php
    }
}


?>

Recursion or Iteration?

Comparing recursion to iteration is like comparing a phillips head screwdriver to a flat head screwdriver. For the most part you could remove any phillips head screw with a flat head, but it would just be easier if you used the screwdriver designed for that screw right?

Some algorithms just lend themselves to recursion because of the way they are designed (Fibonacci sequences, traversing a tree like structure, etc.). Recursion makes the algorithm more succinct and easier to understand (therefore shareable and reusable).

Also, some recursive algorithms use "Lazy Evaluation" which makes them more efficient than their iterative brothers. This means that they only do the expensive calculations at the time they are needed rather than each time the loop runs.

That should be enough to get you started. I'll dig up some articles and examples for you too.

Link 1: Haskel vs PHP (Recursion vs Iteration)

Here is an example where the programmer had to process a large data set using PHP. He shows how easy it would have been to deal with in Haskel using recursion, but since PHP had no easy way to accomplish the same method, he was forced to use iteration to get the result.

http://blog.webspecies.co.uk/2011-05-31/lazy-evaluation-with-php.html

Link 2: Mastering Recursion

Most of recursion's bad reputation comes from the high costs and inefficiency in imperative languages. The author of this article talks about how to optimize recursive algorithms to make them faster and more efficient. He also goes over how to convert a traditional loop into a recursive function and the benefits of using tail-end recursion. His closing words really summed up some of my key points I think:

"recursive programming gives the programmer a better way of organizing code in a way that is both maintainable and logically consistent."

https://developer.ibm.com/articles/l-recurs/

Link 3: Is recursion ever faster than looping? (Answer)

Here is a link to an answer for a stackoverflow question that is similar to yours. The author points out that a lot of the benchmarks associated with either recursing or looping are very language specific. Imperative languages are typically faster using a loop and slower with recursion and vice-versa for functional languages. I guess the main point to take from this link is that it is very difficult to answer the question in a language agnostic / situation blind sense.

Is recursion ever faster than looping?

css background image in a different folder from css

Since you are providing a relative pathway to the image, the image location is looked for from the location in which you have the css file. So if you have the image in a different location to the css file you could either try giving the absolute URL(pathway starting from the root folder) or give the relative file location path. In your case since img and css are in the folder assets to move from location of css file to the img file, you can use '..' operator to refer that the browser has to move 1 folder back and then follow the pathway you have after the '..' operator. This is basically how relative pathway works and you can use it to access resoures in different folders. Hope it helps.

How to get resources directory path programmatically

I'm assuming the contents of src/main/resources/ is copied to WEB-INF/classes/ inside your .war at build time. If that is the case you can just do (substituting real values for the classname and the path being loaded).

URL sqlScriptUrl = MyServletContextListener.class
                       .getClassLoader().getResource("sql/script.sql");

What is bootstrapping?

In terms of it in regards to using the popular Twitter Bootstrap I feel like this type of bootstrapping is the action of integrating a modular component into a Web application without the Web application having to even acknowledge the modular component exists until it needs it or references it.

The developer can seamlessly integrate a default copy of the CSS Twitter Bootstrap theme by simply loading (referencing) it into the Web application. Vuola! Then you may need to override some of these changes, but you can do so in such a way that the resource/component is untouched and completely reusable.

This same concept is how Web Devs implement jQuery APIs and so on, but it's not really expressed by Devs as bootstrapping per se. What it does is it improves flexibility and reusability while allowing the isolation of different components/resources of an app to reside freely either on the same server/s or possibly on a CDN.

NOTE: In computing bootstrapping deals with the MBR and in UNIX it requires a special bootloader or manager which is a small program in ROM that loads the OS into RAM. If you think about it the same concept takes places in the action of the bootstrap loader checking the MBR and loading the OS based on this table which occurs without the OS having any idea that this takes place.

UITableview: How to Disable Selection for Some Rows but Not Others

You can use the tableView:willDisplayCell method to do all the kinds of customization to a tableViewCell.

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
     [cell setSelectionStyle:UITableViewCellSelectionStyleNone];
     [cell setUserInteractionEnabled:NO];

     if (indexPath.section == 1 && indexPath.row == 0)
     {
         [cell setSelectionStyle:UITableViewCellSelectionStyleGray];
         [cell setUserInteractionEnabled:YES];
     }
} 

In this above code, the user can only select the first row in the second section of the tableView. The rest all rows can't be selected. Thanks!~

"Cannot evaluate expression because the code of the current method is optimized" in Visual Studio 2010

Regarding the problem with "Optimize code" property being UNCHECKED yet the code still compiling as optimized: What finally helped me after trying everything was checking the "Enable unmanaged code debugging" checkbox on the same settings page (Project properties - Debug). It doesn't directly relate to the code optimization, but with this enabled, VS no longer optimizes my library and I can debug.

Searching in a ArrayList with custom objects for certain strings

For a custom class to work properly in collections you'll have to implement/override the equals() methods of the class. For sorting also override compareTo().

See this article or google about how to implement those methods properly.

Adding System.Web.Script reference in class library

You need to add a reference to System.Web.Extensions.dll in project for System.Web.Script.Serialization error.

Why is "1000000000000000 in range(1000000000000001)" so fast in Python 3?

The other answers explained it well already, but I'd like to offer another experiment illustrating the nature of range objects:

>>> r = range(5)
>>> for i in r:
        print(i, 2 in r, list(r))

0 True [0, 1, 2, 3, 4]
1 True [0, 1, 2, 3, 4]
2 True [0, 1, 2, 3, 4]
3 True [0, 1, 2, 3, 4]
4 True [0, 1, 2, 3, 4]

As you can see, a range object is an object that remembers its range and can be used many times (even while iterating over it), not just a one-time generator.

How to stretch in width a WPF user control to its window?

Is the Canvas crucial in your window? If not, try removing it and keep the Grid as the main panel. Canvas has no size unless specified, while a Grid normally takes up all available space. Inside the Canvas, the Grid will have no available space.

A weighted version of random.choice

If you don't mind using numpy, you can use numpy.random.choice.

For example:

import numpy

items  = [["item1", 0.2], ["item2", 0.3], ["item3", 0.45], ["item4", 0.05]
elems = [i[0] for i in items]
probs = [i[1] for i in items]

trials = 1000
results = [0] * len(items)
for i in range(trials):
    res = numpy.random.choice(items, p=probs)  #This is where the item is selected!
    results[items.index(res)] += 1
results = [r / float(trials) for r in results]
print "item\texpected\tactual"
for i in range(len(probs)):
    print "%s\t%0.4f\t%0.4f" % (items[i], probs[i], results[i])

If you know how many selections you need to make in advance, you can do it without a loop like this:

numpy.random.choice(items, trials, p=probs)

SELECT max(x) is returning null; how can I make it return 0?

Like this (for MySQL):

SELECT IFNULL(MAX(X), 0) AS MaxX
FROM tbl
WHERE XID = 1

For MSSQL replace IFNULL with ISNULL or for Oracle use NVL

Deleting an element from an array in PHP

If you need to remove multiple elements from an associative array, you can use array_diff_key() (here used with array_flip()):

$my_array = array(
  "key1" => "value 1",
  "key2" => "value 2",
  "key3" => "value 3",
  "key4" => "value 4",
  "key5" => "value 5",
);

$to_remove = array("key2", "key4");

$result = array_diff_key($my_array, array_flip($to_remove));

print_r($result);

Output:

Array ( [key1] => value 1 [key3] => value 3 [key5] => value 5 ) 

How to initialize private static members in C++?

If you want to initialize some compound type (f.e. string) you can do something like that:

class SomeClass {
  static std::list<string> _list;

  public:
    static const std::list<string>& getList() {
      struct Initializer {
         Initializer() {
           // Here you may want to put mutex
           _list.push_back("FIRST");
           _list.push_back("SECOND");
           ....
         }
      }
      static Initializer ListInitializationGuard;
      return _list;
    }
};

As the ListInitializationGuard is a static variable inside SomeClass::getList() method it will be constructed only once, which means that constructor is called once. This will initialize _list variable to value you need. Any subsequent call to getList will simply return already initialized _list object.

Of course you have to access _list object always by calling getList() method.

CSS Resize/Zoom-In effect on Image while keeping Dimensions

You could achieve that simply by wrapping the image by a <div> and adding overflow: hidden to that element:

<div class="img-wrapper">
    <img src="..." />
</div>
.img-wrapper {
    display: inline-block; /* change the default display type to inline-block */
    overflow: hidden;      /* hide the overflow */
}

WORKING DEMO.


Also it's worth noting that <img> element (like the other inline elements) sits on its baseline by default. And there would be a 4~5px gap at the bottom of the image.

That vertical gap belongs to the reserved space of descenders like: g j p q y. You could fix the alignment issue by adding vertical-align property to the image with a value other than baseline.

Additionally for a better user experience, you could add transition to the images.

Thus we'll end up with the following:

.img-wrapper img {
    transition: all .2s ease;
    vertical-align: middle;
}

UPDATED DEMO.

Spring Boot REST API - request timeout?

A fresh answer for Spring Boot 2.2 is required as server.connection-timeout=5000 is deprecated. Each server behaves differently, so server specific properties are recommended instead.

SpringBoot embeds Tomcat by default, if you haven't reconfigured it with Jetty or something else. Use server specific application properties like server.tomcat.connection-timeout or server.jetty.idle-timeout.

How to create .ipa file using Xcode?

Click Product > Archive from the menu, once this is complete open up the Organiser and click the latest version > Distribute > Save for Enterprise or Ad-Hoc Deployment > Choose correct signing > Save to destination

Way to ng-repeat defined number of times instead of repeating over array?

I ran into the same issue. I came across this thread, but didn't like the methods they had here. My solution was using underscore.js, which we had already installed. It's as simple as this:

<ul>
    <li ng-repeat="n in _.range(1,6)"><span>{{n}}</span></li>
</ul>

This will do exactly what you're looking for.

How to check compiler log in sql developer?

I can also use

show errors;

In sql worksheet.

Test for array of string type in TypeScript

Try this:

if (value instanceof Array) {
alert('value is Array!');
} else {
alert('Not an array');
}

referenced before assignment error in python

I think you are using 'global' incorrectly. See Python reference. You should declare variable without global and then inside the function when you want to access global variable you declare it global yourvar.

#!/usr/bin/python

total

def checkTotal():
    global total
    total = 0

See this example:

#!/usr/bin/env python

total = 0

def doA():
    # not accessing global total
    total = 10

def doB():
    global total
    total = total + 1

def checkTotal():
    # global total - not required as global is required
    # only for assignment - thanks for comment Greg
    print total

def main():
    doA()
    doB()
    checkTotal()

if __name__ == '__main__':
    main()

Because doA() does not modify the global total the output is 1 not 11.

Woocommerce get products

<?php  
    $args = array(
        'post_type'      => 'product',
        'posts_per_page' => 10,
        'product_cat'    => 'hoodies'
    );

    $loop = new WP_Query( $args );

    while ( $loop->have_posts() ) : $loop->the_post();
        global $product;
        echo '<br /><a href="'.get_permalink().'">' . woocommerce_get_product_thumbnail().' '.get_the_title().'</a>';
    endwhile;

    wp_reset_query();
?>

This will list all product thumbnails and names along with their links to product page. change the category name and posts_per_page as per your requirement.

How to disable a input in angular2

I think I figured out the problem, this input field is part of a reactive form (?), since you have included formControlName. This means that what you are trying to do by disabling the input field with is_edit is not working, e.g your attempt [disabled]="is_edit", which would in other cases work. With your form you need to do something like this:

toggle() {
  let control = this.myForm.get('name')
  control.disabled ? control.enable() : control.disable();
}

and lose the is_edit altogether.

if you want the input field to be disabled as default, you need to set the form control as:

name: [{value: '', disabled:true}]

Here's a plunker

ImportError: cannot import name main when running pip --version command in windows7 32 bit

Even though the original question seems to be from 2015, this 'bug' seems to affect users installing pip-10.0.0 as well.

The workaround is not to modify pip, however to change the way pip is called. Instead of calling /usr/bin/pip call pip via Python itself. For example, instead of the below:

pip install <package>

If from Python version 2 (or default Python binary is called python) do :

python -m pip install <package>

or if from Python version 3:

python3 -m pip install <package> 

AttributeError: 'datetime' module has no attribute 'strptime'

If I had to guess, you did this:

import datetime

at the top of your code. This means that you have to do this:

datetime.datetime.strptime(date, "%Y-%m-%d")

to access the strptime method. Or, you could change the import statement to this:

from datetime import datetime

and access it as you are.

The people who made the datetime module also named their class datetime:

#module  class    method
datetime.datetime.strptime(date, "%Y-%m-%d")

How to concatenate multiple lines of output to one line?

I like the xargs solution, but if it's important to not collapse spaces, then one might instead do:

sed ':b;$!{N;bb};s/\n/ /g'

That will replace newlines for spaces, without substituting the last line terminator like tr '\n' ' ' would.

This also allows you to use other joining strings besides a space, like a comma, etc, something that xargs cannot do:

$ seq 1 5 | sed ':b;$!{N;bb};s/\n/,/g'
1,2,3,4,5

Max tcp/ip connections on Windows Server 2008

There is a limit on the number of half-open connections, but afaik not for active connections. Although it appears to depend on the type of Windows 2008 server, at least according to this MSFT employee:

It depends on the edition, Web and Foundation editions have connection limits while Standard, Enterprise, and Datacenter do not.

Convert Mat to Array/Vector in OpenCV

If the memory of the Mat mat is continuous (all its data is continuous), you can directly get its data to a 1D array:

std::vector<uchar> array(mat.rows*mat.cols*mat.channels());
if (mat.isContinuous())
    array = mat.data;

Otherwise, you have to get its data row by row, e.g. to a 2D array:

uchar **array = new uchar*[mat.rows];
for (int i=0; i<mat.rows; ++i)
    array[i] = new uchar[mat.cols*mat.channels()];

for (int i=0; i<mat.rows; ++i)
    array[i] = mat.ptr<uchar>(i);

UPDATE: It will be easier if you're using std::vector, where you can do like this:

std::vector<uchar> array;
if (mat.isContinuous()) {
  // array.assign(mat.datastart, mat.dataend); // <- has problems for sub-matrix like mat = big_mat.row(i)
  array.assign(mat.data, mat.data + mat.total()*mat.channels());
} else {
  for (int i = 0; i < mat.rows; ++i) {
    array.insert(array.end(), mat.ptr<uchar>(i), mat.ptr<uchar>(i)+mat.cols*mat.channels());
  }
}

p.s.: For cv::Mats of other types, like CV_32F, you should do like this:

std::vector<float> array;
if (mat.isContinuous()) {
  // array.assign((float*)mat.datastart, (float*)mat.dataend); // <- has problems for sub-matrix like mat = big_mat.row(i)
  array.assign((float*)mat.data, (float*)mat.data + mat.total()*mat.channels());
} else {
  for (int i = 0; i < mat.rows; ++i) {
    array.insert(array.end(), mat.ptr<float>(i), mat.ptr<float>(i)+mat.cols*mat.channels());
  }
}

UPDATE2: For OpenCV Mat data continuity, it can be summarized as follows:

  • Matrices created by imread(), clone(), or a constructor will always be continuous.
  • The only time a matrix will not be continuous is when it borrows data (except the data borrowed is continuous in the big matrix, e.g. 1. single row; 2. multiple rows with full original width) from an existing matrix (i.e. created out of an ROI of a big mat).

Please check out this code snippet for demonstration.

Can HTTP POST be limitless?

POST allows for an arbitrary length of data to be sent to a server, but there are limitations based on timeouts/bandwidth etc.

I think basically, it's safer to assume that it's not okay to send lots of data.

How to remove an item from an array in AngularJS scope?

You can also use this

$scope.persons = $filter('filter')($scope.persons , { id: ('!' + person.id) });

How to store a large (10 digits) integer?

You can store this in a long. A long can store a value from -9223372036854775808 to 9223372036854775807.

Difference between MEAN.js and MEAN.io

The Starter Trade-offs sheet of my comparison spreadsheet has comprehensive one-on-one comparisons between each generator. So no more need to distortedly cherry-pick great things to say about your favorite.

Here is the one between generator-angular-fullstack and MEAN.js. The percentages are values for each benefit based on my personal weightings, where a perfect generator would be 100%

generator- angular- fullstack offers 8% that MEANJS.org doesn't

  • 1.9% Client-side end-to-end tests
  • 0.6% factory
  • 0.5% provider
  • 0.4% SASS
  • 0.4% LESS
  • 0.4% Compass
  • 0.4% decorator
  • 0.4% Endpoint subgenerator
  • 0.4% Comments
  • 0.3% FontAwesome
  • 0.3% Run server in debug mode
  • 0.3% Save generator answers to a file
  • 0.2% constant
  • 0.2% Development build script: ...... replace 3rd party deps with CDN versions
  • 0.2% Authentication - Cookie
  • 0.2% Authentication - JSON Web Token (JWT)
  • 0.2% Server-side logging
  • 0.1% Development build script: run tasks in parallel to speed it up
  • 0.1% Development build script: Renames asset files to prevent browser caching
  • 0.1% Development build script: run end to end tests
  • 0.1% Production build script: safe pre-minification
  • 0.1% Production build script: add CSS vendor prefixes
  • 0.1% Heroku deployment automation
  • 0.1% value
  • 0.1% Jade
  • 0.1% Coffeescript
  • 0.1% Serverside authenticated route restriction
  • 0.1% SASS version of Twitter Bootstrap
  • 0.1% Production build script: compress images
  • 0.1% OpenShift deployment automation

MeanJS.org. offers 9% that generator-angular-fullstack doesn't

  • 3.7% Dedicated/searchable user group: response time mostly under a day
  • 0.4% Generate routes
  • 0.4% Authentication - Oauth
  • 0.4% config
  • 0.4% i18n, localization
  • 0.4% Input application profile
  • 0.3% FEATURE (a.k.a. module, entity, crud-mock)
  • 0.3% Menus system
  • 0.3% Options for making subcomponents
  • 0.3% test - client side
  • 0.3% Javascript performance thing
  • 0.3% Production build script: make static pages for SEO
  • 0.2% Quick install?
  • 0.2% Dedicated/searchable user group
  • 0.1% Development build script: reload build file upon change
  • 0.1% Development build script: coffee files compiled to JS
  • 0.1% controller - server side
  • 0.1% model - server side
  • 0.1% route - server side
  • 0.1% test - server side
  • 0.1% Swig
  • 0.1% Safe from IP Spoofing
  • 0.1% Production build script: uglification
  • 0.0% Approach to views: URLs start with "#!"
  • 0.0% Approach to frontend services and ajax calls: uses $resource

Here is the one between MEAN.io and MEAN.js in a more readable format

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<table border="1" cellpadding="10"><tbody><tr><td valign="top" width="33%"><br><br><h1>MeanJS.org. provides these benefits that MEAN.io. doesn't</h1><br><br><b>Help</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Dedicated/searchable user group for questions, using github issues<br>&nbsp;&nbsp;&nbsp;&nbsp;* There's a book about it<br><b>File Organization</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Basic sourcecode organization, module(-&gt;submodule)-&gt;side<br>&nbsp;&nbsp;&nbsp;&nbsp;* Module directories hold directives<br><b>Code Modularization</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to AngularJS modules, Only one module definition per file<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to AngularJS modules, Don’t alter a module other than where it is defined<br><b>Model</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Object-relational mapping<br>&nbsp;&nbsp;&nbsp;&nbsp;* Server-side validation, server-side example<br>&nbsp;&nbsp;&nbsp;&nbsp;* Client side validation, using Angular 1.3<br><b>View</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to AngularJS views, Directives start with "data-"<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to data readiness, Use ng-init<br><b>Control</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to frontend routing or state changing, URLs start with '#!'<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to frontend routing or state changing, Use query parameters to store route state<br><b>Support for things</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Languages, LESS<br>&nbsp;&nbsp;&nbsp;&nbsp;* Languages, SASS<br><b>Syntax, language and coding</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* JavaScript 5 best practices, Don't use "new"<br><b>Testing</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Testing, using Mocha<br>&nbsp;&nbsp;&nbsp;&nbsp;* End-to-end tests<br>&nbsp;&nbsp;&nbsp;&nbsp;* End-to-end tests, using Protractor<br>&nbsp;&nbsp;&nbsp;&nbsp;* Continuous integration (CI), using Travis<br><b>Development and debugging</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Command line interface (CLI), using Yeoman<br><b>Build</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Build configurations file(s)<br>&nbsp;&nbsp;&nbsp;&nbsp;* Deployment automation, using Azure<br>&nbsp;&nbsp;&nbsp;&nbsp;* Deployment automation, using Digital Ocean, screencast of it<br>&nbsp;&nbsp;&nbsp;&nbsp;* Deployment automation, using Heroku, screencast of it<br><b>Code Generation</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Input application profile<br>&nbsp;&nbsp;&nbsp;&nbsp;* Quick install?<br>&nbsp;&nbsp;&nbsp;&nbsp;* Options for making subcomponents<br>&nbsp;&nbsp;&nbsp;&nbsp;* config generator<br>&nbsp;&nbsp;&nbsp;&nbsp;* controller (client side) generator<br>&nbsp;&nbsp;&nbsp;&nbsp;* directive generator<br>&nbsp;&nbsp;&nbsp;&nbsp;* filter generator<br>&nbsp;&nbsp;&nbsp;&nbsp;* route (client side) generator<br>&nbsp;&nbsp;&nbsp;&nbsp;* service (client side) generator<br>&nbsp;&nbsp;&nbsp;&nbsp;* test - client side<br>&nbsp;&nbsp;&nbsp;&nbsp;* view or view partial generator<br>&nbsp;&nbsp;&nbsp;&nbsp;* controller (server side) generator<br>&nbsp;&nbsp;&nbsp;&nbsp;* model (server side) generator<br>&nbsp;&nbsp;&nbsp;&nbsp;* route (server side) generator<br>&nbsp;&nbsp;&nbsp;&nbsp;* test (server side) generator<br><b>Implemented Functionality</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Account Management, Forgotten Password with Resetting<br>&nbsp;&nbsp;&nbsp;&nbsp;* Chat<br>&nbsp;&nbsp;&nbsp;&nbsp;* CSV processing<br>&nbsp;&nbsp;&nbsp;&nbsp;* E-mail sending system<br>&nbsp;&nbsp;&nbsp;&nbsp;* E-mail sending system, using Nodemailer<br>&nbsp;&nbsp;&nbsp;&nbsp;* E-mail sending system, using its own e-mail implementation<br>&nbsp;&nbsp;&nbsp;&nbsp;* Menus system, state-based<br>&nbsp;&nbsp;&nbsp;&nbsp;* Paypal integration<br>&nbsp;&nbsp;&nbsp;&nbsp;* Responsive design<br>&nbsp;&nbsp;&nbsp;&nbsp;* Social connections management page<br><b>Performance</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Creates a favicon<br><b>Security</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Safe from IP Spoofing<br>&nbsp;&nbsp;&nbsp;&nbsp;* Authorization, Access Contol List (ACL)<br>&nbsp;&nbsp;&nbsp;&nbsp;* Authentication, Cookie<br>&nbsp;&nbsp;&nbsp;&nbsp;* Websocket and RESTful http share security policies<br><br><br></td><td valign="top" width="33%"><br><br><h1>MEAN.io. provides these benefits that MeanJS.org. doesn't</h1><br><br><b>Quality</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Sponsoring company<br><b>Help</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Docs with flatdoc<br><b>Code Modularization</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Share code between projects<br>&nbsp;&nbsp;&nbsp;&nbsp;* Module manager<br><b>View</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to data readiness, Use state.resolve()<br><b>Control</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to frontend code loading, Use AMD with Require.js<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to frontend code loading, using wiredep<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to error handling, Server-side logging<br><b>Client/Server Communication</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Centralized event handling<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to XHR calls, using $http and $q<br><b>Syntax, language and coding</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* JavaScript 5 best practices, Wrap code in an IIFE (SEAF, SIAF)<br><b>Development and debugging</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* API introspection report and testing interface, using Swagger<br>&nbsp;&nbsp;&nbsp;&nbsp;* Command line interface (CLI), using Independent command line interface<br><b>Build</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Development build, add IIFEs (SEAF, SIAF) to executable copies of code<br>&nbsp;&nbsp;&nbsp;&nbsp;* Deployment automation<br>&nbsp;&nbsp;&nbsp;&nbsp;* Deployment automation, using Heroku<br><b>Code Generation</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Scaffolding undo&nbsp;&nbsp;&nbsp;&nbsp;(mean package -d &lt;name&gt;)<br>&nbsp;&nbsp;&nbsp;&nbsp;* FEATURE (a.k.a. module, entity) generator, Menu items added for new features<br><b>Implemented Functionality</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Admin page for users and roles<br>&nbsp;&nbsp;&nbsp;&nbsp;* Content Management System&nbsp;&nbsp;&nbsp;&nbsp;(Use special data-bound directives in your templates.<br>Switch to edit mode and you can edit the values right where you see them)<br>&nbsp;&nbsp;&nbsp;&nbsp;* File Upload<br>&nbsp;&nbsp;&nbsp;&nbsp;* i18n, localization<br>&nbsp;&nbsp;&nbsp;&nbsp;* Menus system, submenus<br>&nbsp;&nbsp;&nbsp;&nbsp;* Search<br>&nbsp;&nbsp;&nbsp;&nbsp;* Search, actually works with backend API<br>&nbsp;&nbsp;&nbsp;&nbsp;* Search, using Elastic Search<br>&nbsp;&nbsp;&nbsp;&nbsp;* Styles, using Bootstrap, using UI Bootstrap AngularJS directives<br>&nbsp;&nbsp;&nbsp;&nbsp;* Text (WYSIWYG) Editor<br>&nbsp;&nbsp;&nbsp;&nbsp;* Text (WYSIWYG) Editor, using medium-editor<br><b>Performance</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Instrumentation, server-side<br><b>Security</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Serverside authenticated route restriction<br>&nbsp;&nbsp;&nbsp;&nbsp;* Authentication, using Oauth, Link multiple Oauth strategies to one account<br>&nbsp;&nbsp;&nbsp;&nbsp;* Authentication, JSON Web Token (JWT)<br><br><br></td><td valign="top" width="33%"><br><br><h1>MEAN.io. and MeanJS.org. both provide these benefits</h1><br><br><b>Quality</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Version Control, using git<br><b>Platforms</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Client-side JS Framework, using AngularJS<br>&nbsp;&nbsp;&nbsp;&nbsp;* Frontend Server/ Framework, using Node.JS<br>&nbsp;&nbsp;&nbsp;&nbsp;* Frontend Server/ Framework, using Node.JS, using Express<br>&nbsp;&nbsp;&nbsp;&nbsp;* API Server/ Framework, using NodeJS<br>&nbsp;&nbsp;&nbsp;&nbsp;* API Server/ Framework, using NodeJS, using Express<br><b>Help</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Dedicated/searchable user group for questions<br>&nbsp;&nbsp;&nbsp;&nbsp;* Dedicated/searchable user group for questions, using Google Groups<br>&nbsp;&nbsp;&nbsp;&nbsp;* Dedicated/searchable user group for questions, using Facebook<br>&nbsp;&nbsp;&nbsp;&nbsp;* Dedicated/searchable user group for questions, response time mostly under a day<br>&nbsp;&nbsp;&nbsp;&nbsp;* Example application<br>&nbsp;&nbsp;&nbsp;&nbsp;* Tutorial screencast in English<br>&nbsp;&nbsp;&nbsp;&nbsp;* Tutorial screencast in English, using Youtube<br>&nbsp;&nbsp;&nbsp;&nbsp;* Dedicated chatroom<br><b>File Organization</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Basic sourcecode organization, module(-&gt;submodule)-&gt;side, with type subfolders<br>&nbsp;&nbsp;&nbsp;&nbsp;* Module directories hold controllers<br>&nbsp;&nbsp;&nbsp;&nbsp;* Module directories hold services<br>&nbsp;&nbsp;&nbsp;&nbsp;* Module directories hold templates<br>&nbsp;&nbsp;&nbsp;&nbsp;* Module directories hold unit tests<br>&nbsp;&nbsp;&nbsp;&nbsp;* Separate route configuration files for each module<br><b>Code Modularization</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Modularized Functionality<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to AngularJS modules, No global 'app' module variable<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to AngularJS modules, No global 'app' module variable without an IIFE<br><b>Model</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Setup of persistent storage<br>&nbsp;&nbsp;&nbsp;&nbsp;* Setup of persistent storage, using NoSQL db<br>&nbsp;&nbsp;&nbsp;&nbsp;* Setup of persistent storage, using NoSQL db, using MongoDB<br><b>View</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* No XHR calls in controllers<br>&nbsp;&nbsp;&nbsp;&nbsp;* Templates, using Angular directives<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to data readiness, prevents Flash of Unstyled/compiled Content (FOUC)<br><b>Control</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to frontend routing or state changing, example of it<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to frontend routing or state changing, State-based routing<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to frontend routing or state changing, State-based routing, using ui-router<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to frontend routing or state changing, HTML5 Mode<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to frontend code loading, using angular.bootstrap()<br><b>Client/Server Communication</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Serve status codes only as responses<br>&nbsp;&nbsp;&nbsp;&nbsp;* Accept nested, JSON parameters<br>&nbsp;&nbsp;&nbsp;&nbsp;* Add timer header to requests<br>&nbsp;&nbsp;&nbsp;&nbsp;* Support for signed and encrypted cookies<br>&nbsp;&nbsp;&nbsp;&nbsp;* Serve URLs based on the route definitions<br>&nbsp;&nbsp;&nbsp;&nbsp;* Can serve headers only<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to XHR calls, using JSON<br>&nbsp;&nbsp;&nbsp;&nbsp;* Approach to XHR calls, using $resource (angular-resource)<br><b>Support for things</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Languages, JavaScript (server side)<br>&nbsp;&nbsp;&nbsp;&nbsp;* Languages, Swig<br><b>Syntax, language and coding</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* JavaScript 5 best practices, Use 'use strict'<br><b>Tool Configuration/customization</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Separate runtime configuration profiles<br><b>Testing</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Testing, using Jasmine<br>&nbsp;&nbsp;&nbsp;&nbsp;* Testing, using Karma<br>&nbsp;&nbsp;&nbsp;&nbsp;* Client-side unit tests<br>&nbsp;&nbsp;&nbsp;&nbsp;* Continuous integration (CI)<br>&nbsp;&nbsp;&nbsp;&nbsp;* Automated device testing, using Live Reload<br>&nbsp;&nbsp;&nbsp;&nbsp;* Server-side integration &amp; unit tests<br>&nbsp;&nbsp;&nbsp;&nbsp;* Server-side integration &amp; unit tests, using Mocha<br><b>Development and debugging</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Command line interface (CLI)<br><b>Build</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Build-time Dependency Management, using npm<br>&nbsp;&nbsp;&nbsp;&nbsp;* Build-time Dependency Management, using bower<br>&nbsp;&nbsp;&nbsp;&nbsp;* Build tool / Task runner, using Grunt<br>&nbsp;&nbsp;&nbsp;&nbsp;* Build tool / Task runner, using gulp<br>&nbsp;&nbsp;&nbsp;&nbsp;* Development build, script<br>&nbsp;&nbsp;&nbsp;&nbsp;* Development build, reload build script file upon change<br>&nbsp;&nbsp;&nbsp;&nbsp;* Development build, copy assets to build or dist or target folder<br>&nbsp;&nbsp;&nbsp;&nbsp;* Development build, html page processing<br>&nbsp;&nbsp;&nbsp;&nbsp;* Development build, html page processing, inject references by searching directories<br>&nbsp;&nbsp;&nbsp;&nbsp;* Development build, html page processing, inject references by searching directories, injects js references<br>&nbsp;&nbsp;&nbsp;&nbsp;* Development build, html page processing, inject references by searching directories, injects css references<br>&nbsp;&nbsp;&nbsp;&nbsp;* Development build, LESS/SASS/etc files are linted, compiled<br>&nbsp;&nbsp;&nbsp;&nbsp;* Development build, JavaScript style checking<br>&nbsp;&nbsp;&nbsp;&nbsp;* Development build, JavaScript style checking, using jshint or jslint<br>&nbsp;&nbsp;&nbsp;&nbsp;* Development build, run unit tests<br>&nbsp;&nbsp;&nbsp;&nbsp;* Production build, script<br>&nbsp;&nbsp;&nbsp;&nbsp;* Production build, concatenation (aggregation, globbing, bundling)&nbsp;&nbsp;&nbsp;&nbsp;(If you add debug:true to your config/env/development.js the will not be <br>uglified)<br>&nbsp;&nbsp;&nbsp;&nbsp;* Production build, minification<br>&nbsp;&nbsp;&nbsp;&nbsp;* Production build, safe pre-minification, using ng-annotate<br>&nbsp;&nbsp;&nbsp;&nbsp;* Production build, uglification<br>&nbsp;&nbsp;&nbsp;&nbsp;* Production build, make static pages for SEO<br><b>Code Generation</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* FEATURE (a.k.a. module, entity) generator&nbsp;&nbsp;&nbsp;&nbsp;(README.md<br>feature css<br>routes<br>controller<br>view<br>additional menu item)<br><b>Implemented Functionality</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* 404 Page<br>&nbsp;&nbsp;&nbsp;&nbsp;* 500 Page<br>&nbsp;&nbsp;&nbsp;&nbsp;* Account Management<br>&nbsp;&nbsp;&nbsp;&nbsp;* Account Management, register/login/logout<br>&nbsp;&nbsp;&nbsp;&nbsp;* Account Management, is password manager friendly<br>&nbsp;&nbsp;&nbsp;&nbsp;* Front-end CRUD<br>&nbsp;&nbsp;&nbsp;&nbsp;* Full-stack CRUD<br>&nbsp;&nbsp;&nbsp;&nbsp;* Full-stack CRUD, with Read<br>&nbsp;&nbsp;&nbsp;&nbsp;* Full-stack CRUD, with Create, Update and Delete<br>&nbsp;&nbsp;&nbsp;&nbsp;* Google Analytics<br>&nbsp;&nbsp;&nbsp;&nbsp;* Menus system<br>&nbsp;&nbsp;&nbsp;&nbsp;* Realtime data sync<br>&nbsp;&nbsp;&nbsp;&nbsp;* Realtime data sync, using socket.io<br>&nbsp;&nbsp;&nbsp;&nbsp;* Styles, using Bootstrap<br><b>Performance</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* Javascript performance thing<br>&nbsp;&nbsp;&nbsp;&nbsp;* Javascript performance thing, using lodash<br>&nbsp;&nbsp;&nbsp;&nbsp;* One event-loop thread handles all requests<br>&nbsp;&nbsp;&nbsp;&nbsp;* Configurable response caching&nbsp;&nbsp;&nbsp;&nbsp;(Express plugin<br><b>https</b>://www.npmjs.org/package/apicache)<br>&nbsp;&nbsp;&nbsp;&nbsp;* Clustered HTTP sessions<br><b>Security</b>:<br>&nbsp;&nbsp;&nbsp;&nbsp;* JavaScript obfuscation<br>&nbsp;&nbsp;&nbsp;&nbsp;* https<br>&nbsp;&nbsp;&nbsp;&nbsp;* Authentication, using Oauth<br>&nbsp;&nbsp;&nbsp;&nbsp;* Authentication, Basic&nbsp;&nbsp;&nbsp;&nbsp;(With Passport or others)<br>&nbsp;&nbsp;&nbsp;&nbsp;* Authentication, Digest&nbsp;&nbsp;&nbsp;&nbsp;(With Passport or others)<br>&nbsp;&nbsp;&nbsp;&nbsp;* Authentication, Token&nbsp;&nbsp;&nbsp;&nbsp;(With Passport or others)<br></td></tr></tbody></table>
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How do I convert a list into a string with spaces in Python?

For Non String list we can do like this as well

" ".join(map(str, my_list))

What is the idiomatic Go equivalent of C's ternary operator?

One-liners, though shunned by the creators, have their place.

This one solves the lazy evaluation problem by letting you, optionally, pass functions to be evaluated if necessary:

func FullTernary(e bool, a, b interface{}) interface{} {
    if e {
        if reflect.TypeOf(a).Kind() == reflect.Func {
            return a.(func() interface{})()
        }
        return a
    }
    if reflect.TypeOf(b).Kind() == reflect.Func {
        return b.(func() interface{})()
    }
    return b
}

func demo() {
    a := "hello"
    b := func() interface{} { return a + " world" }
    c := func() interface{} { return func() string { return "bye" } }
    fmt.Println(FullTernary(true, a, b).(string)) // cast shown, but not required
    fmt.Println(FullTernary(false, a, b))
    fmt.Println(FullTernary(true, b, a))
    fmt.Println(FullTernary(false, b, a))
    fmt.Println(FullTernary(true, c, nil).(func() string)())
}

Output

hello
hello world
hello world
hello
bye
  • Functions passed in must return an interface{} to satisfy the internal cast operation.
  • Depending on the context, you might choose to cast the output to a specific type.
  • If you wanted to return a function from this, you would need to wrap it as shown with c.

The standalone solution here is also nice, but could be less clear for some uses.

return SQL table as JSON in python

Personally I prefer SQLObject for this sort of thing. I adapted some quick-and-dirty test code I had to get this:

import simplejson

from sqlobject import *

# Replace this with the URI for your actual database
connection = connectionForURI('sqlite:/:memory:')
sqlhub.processConnection = connection

# This defines the columns for your database table. See SQLObject docs for how it
# does its conversions for class attributes <-> database columns (underscores to camel
# case, generally)

class Song(SQLObject):

    name = StringCol()
    artist = StringCol()
    album = StringCol()

# Create fake data for demo - this is not needed for the real thing
def MakeFakeDB():
    Song.createTable()
    s1 = Song(name="B Song",
              artist="Artist1",
              album="Album1")
    s2 = Song(name="A Song",
              artist="Artist2",
              album="Album2")

def Main():
    # This is an iterable, not a list
    all_songs = Song.select().orderBy(Song.q.name)

    songs_as_dict = []

    for song in all_songs:
        song_as_dict = {
            'name' : song.name,
            'artist' : song.artist,
            'album' : song.album}
        songs_as_dict.append(song_as_dict)

    print simplejson.dumps(songs_as_dict)


if __name__ == "__main__":
    MakeFakeDB()
    Main()

How to programmatically set style attribute in a view

You can do style attributes like so:

Button myButton = new Button(this, null,android.R.attr.buttonBarButtonStyle);

in place of:

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/btn"
    style="?android:attr/buttonBarButtonStyle"

    />

How do I add 24 hours to a unix timestamp in php?

A Unix timestamp is simply the number of seconds since January the first 1970, so to add 24 hours to a Unix timestamp we just add the number of seconds in 24 hours. (24 * 60 *60)

time() + 24*60*60;

Can a relative sitemap url be used in a robots.txt?

Google crawlers are not smart enough, they can't crawl relative URLs, that's why it's always recommended to use absolute URL's for better crawlability and indexability.

Therefore, you can not use this variation

> sitemap: /sitemap.xml

Recommended syntax is

Sitemap: https://www.yourdomain.com/sitemap.xml

Note:

  • Don't forgot to capitalise the first letter in "sitemap"
  • Don't forgot to put space after "Sitemap:"

The breakpoint will not currently be hit. No symbols have been loaded for this document in a Silverlight application

One possible scenario is that if your ASP project is referencing some code in an Application(rather than a dll) then the symbols won't be loaded.

I had to change the referenced application to a Class Library temporarily while I debugged the code.

Difference between INNER JOIN and LEFT SEMI JOIN

Tried in Hive and got the below output

table1

1,wqe,chennai,india

2,stu,salem,india

3,mia,bangalore,india

4,yepie,newyork,USA

table2

1,wqe,chennai,india

2,stu,salem,india

3,mia,bangalore,india

5,chapie,Los angels,USA

Inner Join

SELECT * FROM table1 INNER JOIN table2 ON (table1.id = table2.id);

1 wqe chennai india 1 wqe chennai india

2 stu salem india 2 stu salem india

3 mia bangalore india 3 mia bangalore india

Left Join

SELECT * FROM table1 LEFT JOIN table2 ON (table1.id = table2.id);

1 wqe chennai india 1 wqe chennai india

2 stu salem india 2 stu salem india

3 mia bangalore india 3 mia bangalore india

4 yepie newyork USA NULL NULL NULL NULL

Left Semi Join

SELECT * FROM table1 LEFT SEMI JOIN table2 ON (table1.id = table2.id);

1 wqe chennai india

2 stu salem india

3 mia bangalore india

note: Only records in left table are displayed whereas for Left Join both the table records displayed

How do I tell if an object is a Promise?

Update: This is no longer the best answer. Please vote up my other answer instead.

obj instanceof Promise

should do it. Note that this may only work reliably with native es6 promises.

If you're using a shim, a promise library or anything else pretending to be promise-like, then it may be more appropriate to test for a "thenable" (anything with a .then method), as shown in other answers here.

Output array to CSV in Ruby

I've got this down to just one line.

rows = [['a1', 'a2', 'a3'],['b1', 'b2', 'b3', 'b4'], ['c1', 'c2', 'c3'], ... ]
csv_str = rows.inject([]) { |csv, row|  csv << CSV.generate_line(row) }.join("")
#=> "a1,a2,a3\nb1,b2,b3\nc1,c2,c3\n" 

Do all of the above and save to a csv, in one line.

File.open("ss.csv", "w") {|f| f.write(rows.inject([]) { |csv, row|  csv << CSV.generate_line(row) }.join(""))}

NOTE:

To convert an active record database to csv would be something like this I think

CSV.open(fn, 'w') do |csv|
  csv << Model.column_names
  Model.where(query).each do |m|
    csv << m.attributes.values
  end
end

Hmm @tamouse, that gist is somewhat confusing to me without reading the csv source, but generically, assuming each hash in your array has the same number of k/v pairs & that the keys are always the same, in the same order (i.e. if your data is structured), this should do the deed:

rowid = 0
CSV.open(fn, 'w') do |csv|
  hsh_ary.each do |hsh|
    rowid += 1
    if rowid == 1
      csv << hsh.keys# adding header row (column labels)
    else
      csv << hsh.values
    end# of if/else inside hsh
  end# of hsh's (rows)
end# of csv open

If your data isn't structured this obviously won't work

Creating a UITableView Programmatically

When you register a class, and use dequeueReusableCellWithIdentifier:forIndexPath:, the dequeue method is guaranteed to return a cell, so your if (cell == nil) clause is never entered. So, just do it the old way, don't register the class, and use dequeueReusableCellWithIdentifier:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"newFriendCell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) {
        cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
    }
//etc.
return cell;
}

As for the segue, it can't be called because you can't make a segue to a table that you've created in code, not in IB. Again, go back to the old way and use tableView:didSelectRowAtIndexPath: which will be called when you select a cell. Instantiate your detail controller there and do the trasition in code.

After edit:

I didn't see your added code there. You've implemented didDeselectRowAtIndexPath rather than didSelectRowAtIndexPath. If you change that, your segue should work.

How to control size of list-style-type disc in CSS?

If you choose to use inline SVG to render your bullets, you can use width and height properties to control their size:

_x000D_
_x000D_
ul {_x000D_
  list-style-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='10' height='10' viewBox='-1 -1 2 2'><circle r='1' /></svg>");_x000D_
}_x000D_
_x000D_
.x {_x000D_
  list-style-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='10' height='10' viewBox='-1 -1 2 2'><circle r='0.5' /></svg>");_x000D_
}_x000D_
_x000D_
.x_alternative {_x000D_
  list-style-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='10' height='10' viewBox='-2.2 -2.4 4 4'><circle r='1' /></svg>");_x000D_
}
_x000D_
<ul>_x000D_
  <li>foo</li>_x000D_
  <li>bar</li>_x000D_
  <li>baz</li>_x000D_
</ul>_x000D_
_x000D_
<ul class="x">_x000D_
  <li>foo</li>_x000D_
  <li>bar</li>_x000D_
  <li>baz</li>_x000D_
</ul>_x000D_
_x000D_
<ul class="x_alternative">_x000D_
  <li>foo</li>_x000D_
  <li>bar</li>_x000D_
  <li>baz</li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

Click here for an easy explanation of the viewBox.

How to replace item in array?

Here is the basic answer made into a reusable function:

function arrayFindReplace(array, findValue, replaceValue){
    while(array.indexOf(findValue) !== -1){
        let index = array.indexOf(findValue);
        array[index] = replaceValue;
    }
}

How to keep onItemSelected from firing off on a newly instantiated Spinner?

mYear.setOnItemSelectedListener(new OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View arg1, int item, long arg3) {
                if (mYearSpinnerAdapter.isEnabled(item)) {

                }
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
            }
        });

React-Router External link

Using React with Typescript you get an error as the function must return a react element, not void. So I did it this way using the Route render method (and using React router v4):

redirectToHomePage = (): null => {
    window.location.reload();
    return null;
  };    
<Route exact path={'/'} render={this.redirectToHomePage} />

Where you could instead also use window.location.assign(), window.location.replace() etc

Checking the equality of two slices

In case that you are interested in writing a test, then github.com/stretchr/testify/assert is your friend.

Import the library at the very beginning of the file:

import (
    "github.com/stretchr/testify/assert"
)

Then inside the test you do:


func TestEquality_SomeSlice (t * testing.T) {
    a := []int{1, 2}
    b := []int{2, 1}
    assert.Equal(t, a, b)
}

The error prompted will be:

                Diff:
                --- Expected
                +++ Actual
                @@ -1,4 +1,4 @@
                 ([]int) (len=2) {
                + (int) 1,
                  (int) 2,
                - (int) 2,
                  (int) 1,
Test:           TestEquality_SomeSlice

How to make Firefox headless programmatically in Selenium with Python?

from selenium.webdriver.firefox.options import Options

if __name__ == "__main__":
    options = Options()
    options.add_argument('-headless')
    driver = Firefox(executable_path='geckodriver', firefox_options=options) 
    wait = WebDriverWait(driver, timeout=10)
    driver.get('http://www.google.com')

Tested, works as expected and this is from Official - Headless Mode | Mozilla

How to get ER model of database from server with Workbench

On mac, press Command + R or got to Database -> Reverse Engineer and keep selecting your requirements and continue

enter image description here

How to add facebook share button on my website?

You don't need all that code. All you need are the following lines:

<a href="https://www.facebook.com/sharer/sharer.php?u=example.org" target="_blank">
  Share on Facebook
</a>

Documentation can be found at https://developers.facebook.com/docs/reference/plugins/share-links/

What's the difference between Cache-Control: max-age=0 and no-cache?

By the way, it's worth noting that some mobile devices, particularly Apple products like iPhone/iPad completely ignore headers like no-cache, no-store, Expires: 0, or whatever else you may try to force them to not re-use expired form pages.

This has caused us no end of headaches as we try to get the issue of a user's iPad say, being left asleep on a page they have reached through a form process, say step 2 of 3, and then the device totally ignores the store/cache directives, and as far as I can tell, simply takes what is a virtual snapshot of the page from its last state, that is, ignoring what it was told explicitly, and, not only that, taking a page that should not be stored, and storing it without actually checking it again, which leads to all kinds of strange Session issues, among other things.

I'm just adding this in case someone comes along and can't figure out why they are getting session errors with particularly iphones and ipads, which seem by far to be the worst offenders in this area.

I've done fairly extensive debugger testing with this issue, and this is my conclusion, the devices ignore these directives completely.

Even in regular use, I've found that some mobiles also totally fail to check for new versions via say, Expires: 0 then checking last modified dates to determine if it should get a new one.

It simply doesn't happen, so what I was forced to do was add query strings to the css/js files I needed to force updates on, which tricks the stupid mobile devices into thinking it's a file it does not have, like: my.css?v=1, then v=2 for a css/js update. This largely works.

User browsers also, by the way, if left to their defaults, as of 2016, as I continuously discover (we do a LOT of changes and updates to our site) also fail to check for last modified dates on such files, but the query string method fixes that issue. This is something I've noticed with clients and office people who tend to use basic normal user defaults on their browsers, and have no awareness of caching issues with css/js etc, almost invariably fail to get the new css/js on change, which means the defaults for their browsers, mostly MSIE / Firefox, are not doing what they are told to do, they ignore changes and ignore last modified dates and do not validate, even with Expires: 0 set explicitly.

This was a good thread with a lot of good technical information, but it's also important to note how bad the support for this stuff is in particularly mobile devices. Every few months I have to add more layers of protection against their failure to follow the header commands they receive, or to properly interpet those commands.

Javascript: console.log to html

A little late to the party, but I took @Hristiyan Dodov's answer a bit further still.

All console methods are now rewired and in case of overflowing text, an optional autoscroll to bottom is included. Colors are now based on the logging method rather than the arguments.

_x000D_
_x000D_
rewireLoggingToElement(_x000D_
    () => document.getElementById("log"),_x000D_
    () => document.getElementById("log-container"), true);_x000D_
_x000D_
function rewireLoggingToElement(eleLocator, eleOverflowLocator, autoScroll) {_x000D_
    fixLoggingFunc('log');_x000D_
    fixLoggingFunc('debug');_x000D_
    fixLoggingFunc('warn');_x000D_
    fixLoggingFunc('error');_x000D_
    fixLoggingFunc('info');_x000D_
_x000D_
    function fixLoggingFunc(name) {_x000D_
        console['old' + name] = console[name];_x000D_
        console[name] = function(...arguments) {_x000D_
            const output = produceOutput(name, arguments);_x000D_
            const eleLog = eleLocator();_x000D_
_x000D_
            if (autoScroll) {_x000D_
                const eleContainerLog = eleOverflowLocator();_x000D_
                const isScrolledToBottom = eleContainerLog.scrollHeight - eleContainerLog.clientHeight <= eleContainerLog.scrollTop + 1;_x000D_
                eleLog.innerHTML += output + "<br>";_x000D_
                if (isScrolledToBottom) {_x000D_
                    eleContainerLog.scrollTop = eleContainerLog.scrollHeight - eleContainerLog.clientHeight;_x000D_
                }_x000D_
            } else {_x000D_
                eleLog.innerHTML += output + "<br>";_x000D_
            }_x000D_
_x000D_
            console['old' + name].apply(undefined, arguments);_x000D_
        };_x000D_
    }_x000D_
_x000D_
    function produceOutput(name, args) {_x000D_
        return args.reduce((output, arg) => {_x000D_
            return output +_x000D_
                "<span class=\"log-" + (typeof arg) + " log-" + name + "\">" +_x000D_
                    (typeof arg === "object" && (JSON || {}).stringify ? JSON.stringify(arg) : arg) +_x000D_
                "</span>&nbsp;";_x000D_
        }, '');_x000D_
    }_x000D_
}_x000D_
_x000D_
_x000D_
setInterval(() => {_x000D_
  const method = (['log', 'debug', 'warn', 'error', 'info'][Math.floor(Math.random() * 5)]);_x000D_
  console[method](method, 'logging something...');_x000D_
}, 200);
_x000D_
#log-container { overflow: auto; height: 150px; }_x000D_
_x000D_
.log-warn { color: orange }_x000D_
.log-error { color: red }_x000D_
.log-info { color: skyblue }_x000D_
.log-log { color: silver }_x000D_
_x000D_
.log-warn, .log-error { font-weight: bold; }
_x000D_
<div id="log-container">_x000D_
  <pre id="log"></pre>_x000D_
</div>
_x000D_
_x000D_
_x000D_

is there any alternative for ng-disabled in angular2?

Yes You can either set [disabled]= "true" or if it is an radio button or checkbox then you can simply use disable

For radio button:

<md-radio-button disabled>Select color</md-radio-button>

For dropdown:

<ng-select (selected)="someFunction($event)" [disabled]="true"></ng-select>

Makefile: How to correctly include header file and its directory?

Try INC_DIR=../ ../StdCUtil.

Then, set CCFLAGS=-c -Wall $(addprefix -I,$(INC_DIR))

EDIT: Also, modify your #include to be #include <StdCUtil/split.h> so that the compiler knows to use -I rather than local path of the .cpp using the #include.

@import vs #import - iOS 7

History:

#include => #import => .pch => @import

[#include vs #import]
[.pch - Precompiled header]

Module - @import

Product Name == Product Module Name 

@import module declaration says to compiler to load a precompiled binary of framework which decrease a building time. Modular Framework contains .modulemap[About]

If module feature is enabled in Xcode project #include and #import directives are automatically converted to @import that brings all advantages

enter image description here

Angular routerLink does not navigate to the corresponding component

For not very sharp eyes like mine, I had href instead of routerLink, took me a few searches to figure that out #facepalm.

Cordova : Requirements check failed for JDK 1.8 or greater

I faced the same issue with jdk1.8.0_201.It got resolved when I made JAVA_HOME=C:\Program Files\Java\jdk1.8.0_201 and added "C:\Program Files\Java\jdk1.8.0_201\bin" in path variable

How to "perfectly" override a dict?

You can write an object that behaves like a dict quite easily with ABCs (Abstract Base Classes) from the collections.abc module. It even tells you if you missed a method, so below is the minimal version that shuts the ABC up.

from collections.abc import MutableMapping


class TransformedDict(MutableMapping):
    """A dictionary that applies an arbitrary key-altering
       function before accessing the keys"""

    def __init__(self, *args, **kwargs):
        self.store = dict()
        self.update(dict(*args, **kwargs))  # use the free update to set keys

    def __getitem__(self, key):
        return self.store[self._keytransform(key)]

    def __setitem__(self, key, value):
        self.store[self._keytransform(key)] = value

    def __delitem__(self, key):
        del self.store[self._keytransform(key)]

    def __iter__(self):
        return iter(self.store)
    
    def __len__(self):
        return len(self.store)

    def _keytransform(self, key):
        return key

You get a few free methods from the ABC:

class MyTransformedDict(TransformedDict):

    def _keytransform(self, key):
        return key.lower()


s = MyTransformedDict([('Test', 'test')])

assert s.get('TEST') is s['test']   # free get
assert 'TeSt' in s                  # free __contains__
                                    # free setdefault, __eq__, and so on

import pickle
# works too since we just use a normal dict
assert pickle.loads(pickle.dumps(s)) == s

I wouldn't subclass dict (or other builtins) directly. It often makes no sense, because what you actually want to do is implement the interface of a dict. And that is exactly what ABCs are for.

need to add a class to an element

You can use result.className = 'red';, but you can also use result.classList.add('red');. The .classList.add(str) way is usually easier if you need to add a class in general, and don't want to check if the class is already in the list of classes.

nodejs - How to read and output jpg image?

Here is how you can read the entire file contents, and if done successfully, start a webserver which displays the JPG image in response to every request:

var http = require('http')
var fs = require('fs')

fs.readFile('image.jpg', function(err, data) {
  if (err) throw err // Fail if the file can't be read.
  http.createServer(function(req, res) {
    res.writeHead(200, {'Content-Type': 'image/jpeg'})
    res.end(data) // Send the file data to the browser.
  }).listen(8124)
  console.log('Server running at http://localhost:8124/')
})

Note that the server is launched by the "readFile" callback function and the response header has Content-Type: image/jpeg.

[Edit] You could even embed the image in an HTML page directly by using an <img> with a data URI source. For example:

  res.writeHead(200, {'Content-Type': 'text/html'});
  res.write('<html><body><img src="data:image/jpeg;base64,')
  res.write(Buffer.from(data).toString('base64'));
  res.end('"/></body></html>');

How to set timeout in Retrofit library?

You can set timeouts on the underlying HTTP client. If you don't specify a client, Retrofit will create one with default connect and read timeouts. To set your own timeouts, you need to configure your own client and supply it to the RestAdapter.Builder.

An option is to use the OkHttp client, also from Square.

1. Add the library dependency

In the build.gradle, include this line:

compile 'com.squareup.okhttp:okhttp:x.x.x'

Where x.x.x is the desired library version.

2. Set the client

For example, if you want to set a timeout of 60 seconds, do this way for Retrofit before version 2 and Okhttp before version 3 (FOR THE NEWER VERSIONS, SEE THE EDITS):

public RestAdapter providesRestAdapter(Gson gson) {
    final OkHttpClient okHttpClient = new OkHttpClient();
    okHttpClient.setReadTimeout(60, TimeUnit.SECONDS);
    okHttpClient.setConnectTimeout(60, TimeUnit.SECONDS);

    return new RestAdapter.Builder()
        .setEndpoint(BuildConfig.BASE_URL)
        .setConverter(new GsonConverter(gson))
        .setClient(new OkClient(okHttpClient))
        .build();
}

EDIT 1

For okhttp versions since 3.x.x, you have to set the dependency this way:

compile 'com.squareup.okhttp3:okhttp:x.x.x'

And set the client using the builder pattern:

final OkHttpClient okHttpClient = new OkHttpClient.Builder()
        .readTimeout(60, TimeUnit.SECONDS)
        .connectTimeout(60, TimeUnit.SECONDS)
        .build();

More info in Timeouts


EDIT 2

Retrofit versions since 2.x.x also uses the builder pattern, so change the return block above to this:

return new Retrofit.Builder()
    .baseUrl(BuildConfig.BASE_URL)
    .addConverterFactory(GsonConverterFactory.create())
    .client(okHttpClient)
    .build();

If using a code like my providesRestAdapter method, then change the method return type to Retrofit.

More info in Retrofit 2 — Upgrade Guide from 1.9


ps: If your minSdkVersion is greater than 8, you can use TimeUnit.MINUTES:

okHttpClient.setReadTimeout(1, TimeUnit.MINUTES);
okHttpClient.setConnectTimeout(1, TimeUnit.MINUTES);

For more details about the units, see TimeUnit.

MySQL - Meaning of "PRIMARY KEY", "UNIQUE KEY" and "KEY" when used together while creating a table

Just to add to the other answers, the documentation gives this explanation:

  • KEY is normally a synonym for INDEX. The key attribute PRIMARY KEY can also be specified as just KEY when given in a column definition. This was implemented for compatibility with other database systems.

  • A UNIQUE index creates a constraint such that all values in the index must be distinct. An error occurs if you try to add a new row with a key value that matches an existing row. For all engines, a UNIQUE index permits multiple NULL values for columns that can contain NULL.

  • A PRIMARY KEY is a unique index where all key columns must be defined as NOT NULL. If they are not explicitly declared as NOT NULL, MySQL declares them so implicitly (and silently). A table can have only one PRIMARY KEY. The name of a PRIMARY KEY is always PRIMARY, which thus cannot be used as the name for any other kind of index.

Can I replace groups in Java regex?

Add a third group by adding parens around .*, then replace the subsequence with "number" + m.group(2) + "1". e.g.:

String output = m.replaceFirst("number" + m.group(2) + "1");

How to open an external file from HTML

You may need an extra "/"

<a href="file:///server/directory/file.xlsx">Click me!</a>

How to retrieve a module's path?

If you wish to do this dynamically in a "program" try this code:
My point is, you may not know the exact name of the module to "hardcode" it. It may be selected from a list or may not be currently running to use __file__.

(I know, it will not work in Python 3)

global modpath
modname = 'os' #This can be any module name on the fly
#Create a file called "modname.py"
f=open("modname.py","w")
f.write("import "+modname+"\n")
f.write("modpath = "+modname+"\n")
f.close()
#Call the file with execfile()
execfile('modname.py')
print modpath
<module 'os' from 'C:\Python27\lib\os.pyc'>

I tried to get rid of the "global" issue but found cases where it did not work I think "execfile()" can be emulated in Python 3 Since this is in a program, it can easily be put in a method or module for reuse.

Do we have router.reload in vue-router?

function removeHash () { 
    history.pushState("", document.title, window.location.pathname
                                          + window.location.search);
}


App.$router.replace({name:"my-route", hash: '#update'})
App.$router.replace({name:"my-route", hash: ' ', params: {a: 100} })
setTimeout(removeHash, 0)

Notes:

  1. And the # must have some value after it.
  2. The second route hash is a space, not empty string.
  3. setTimeout, not $nextTick to keep the url clean.

Set value of hidden field in a form using jQuery's ".val()" doesn't work

<javascript>


slots=''; hidden=''; basket = 0;

    cost_per_slot = $("#cost_per_slot").val();
    //cost_per_slot = parseFloat(cost_per_slot).toFixed(2)

    for (i=0; i< check_array.length; i++) {
        slots += check_array[i] + '\r\n';
        hidden += check_array[i].substring(0, 8) + '|';
        basket = (basket + parseFloat(cost_per_slot));
    }

    // Populate the Selected Slots section
    $("#selected_slots").html(slots);

    // Update hidden slots_booked form element with booked slots
    $("#slots_booked").val(hidden);     

    // Update basket total box
    basket = basket.toFixed(2);
    $("#total").html(basket);

How to split comma separated string using JavaScript?

_x000D_
_x000D_
var result;_x000D_
result = "1,2,3".split(","); _x000D_
console.log(result);
_x000D_
_x000D_
_x000D_

More info on W3Schools describing the String Split function.

javascript: pause setTimeout();

I needed to calculate the elapsed and remaining time to show a progress-bar. It was not easy using the accepted answer. 'setInterval' is better than 'setTimeout' for this task. So, I created this Timer class that you can use in any project.

https://jsfiddle.net/ashraffayad/t0mmv853/

'use strict';


    //Constructor
    var Timer = function(cb, delay) {
      this.cb = cb;
      this.delay = delay;
      this.elapsed = 0;
      this.remaining = this.delay - self.elapsed;
    };

    console.log(Timer);

    Timer.prototype = function() {
      var _start = function(x, y) {
          var self = this;
          if (self.elapsed < self.delay) {
            clearInterval(self.interval);
            self.interval = setInterval(function() {
              self.elapsed += 50;
              self.remaining = self.delay - self.elapsed;
              console.log('elapsed: ' + self.elapsed, 
                          'remaining: ' + self.remaining, 
                          'delay: ' + self.delay);
              if (self.elapsed >= self.delay) {
                clearInterval(self.interval);
                self.cb();
              }
            }, 50);
          }
        },
        _pause = function() {
          var self = this;
          clearInterval(self.interval);
        },
        _restart = function() {
          var self = this;
          self.elapsed = 0;
          console.log(self);
          clearInterval(self.interval);
          self.start();
        };

      //public member definitions
      return {
        start: _start,
        pause: _pause,
        restart: _restart
      };
    }();


    // - - - - - - - - how to use this class

    var restartBtn = document.getElementById('restart');
    var pauseBtn = document.getElementById('pause');
    var startBtn = document.getElementById('start');

    var timer = new Timer(function() {
      console.log('Done!');
    }, 2000);

    restartBtn.addEventListener('click', function(e) {
      timer.restart();
    });
    pauseBtn.addEventListener('click', function(e) {
      timer.pause();
    });
    startBtn.addEventListener('click', function(e) {
      timer.start();
    });

Why do we use volatile keyword?

Consider this code,

int some_int = 100;

while(some_int == 100)
{
   //your code
}

When this program gets compiled, the compiler may optimize this code, if it finds that the program never ever makes any attempt to change the value of some_int, so it may be tempted to optimize the while loop by changing it from while(some_int == 100) to something which is equivalent to while(true) so that the execution could be fast (since the condition in while loop appears to be true always). (if the compiler doesn't optimize it, then it has to fetch the value of some_int and compare it with 100, in each iteration which obviously is a little bit slow.)

However, sometimes, optimization (of some parts of your program) may be undesirable, because it may be that someone else is changing the value of some_int from outside the program which compiler is not aware of, since it can't see it; but it's how you've designed it. In that case, compiler's optimization would not produce the desired result!

So, to ensure the desired result, you need to somehow stop the compiler from optimizing the while loop. That is where the volatile keyword plays its role. All you need to do is this,

volatile int some_int = 100; //note the 'volatile' qualifier now!

In other words, I would explain this as follows:

volatile tells the compiler that,

"Hey compiler, I'm volatile and, you know, I can be changed by some XYZ that you're not even aware of. That XYZ could be anything. Maybe some alien outside this planet called program. Maybe some lightning, some form of interrupt, volcanoes, etc can mutate me. Maybe. You never know who is going to change me! So O you ignorant, stop playing an all-knowing god, and don't dare touch the code where I'm present. Okay?"

Well, that is how volatile prevents the compiler from optimizing code. Now search the web to see some sample examples.


Quoting from the C++ Standard ($7.1.5.1/8)

[..] volatile is a hint to the implementation to avoid aggressive optimization involving the object because the value of the object might be changed by means undetectable by an implementation.[...]

Related topic:

Does making a struct volatile make all its members volatile?

Doing a cleanup action just before Node.js exits

UPDATE:

You can register a handler for process.on('exit') and in any other case(SIGINT or unhandled exception) to call process.exit()

process.stdin.resume();//so the program will not close instantly

function exitHandler(options, exitCode) {
    if (options.cleanup) console.log('clean');
    if (exitCode || exitCode === 0) console.log(exitCode);
    if (options.exit) process.exit();
}

//do something when app is closing
process.on('exit', exitHandler.bind(null,{cleanup:true}));

//catches ctrl+c event
process.on('SIGINT', exitHandler.bind(null, {exit:true}));

// catches "kill pid" (for example: nodemon restart)
process.on('SIGUSR1', exitHandler.bind(null, {exit:true}));
process.on('SIGUSR2', exitHandler.bind(null, {exit:true}));

//catches uncaught exceptions
process.on('uncaughtException', exitHandler.bind(null, {exit:true}));

Decompile Python 2.7 .pyc

Here is a great tool to decompile pyc files.

It was coded by me and supports python 1.0 - 3.3

Its based on uncompyle2 and decompyle++

http://sourceforge.net/projects/easypythondecompiler/

Scp command syntax for copying a folder from local machine to a remote server

scp -r C:/site user@server_ip:path

path is the place, where site will be copied into the remote server


EDIT: As I said in my comment, try pscp, as you want to use scp using PuTTY.

The other option is WinSCP

How do I get cURL to not show the progress bar?

In curl version 7.22.0 on Ubuntu and 7.24.0 on OSX the solution to not show progress but to show errors is to use both -s (--silent) and -S (--show-error) like so:

curl -sS http://google.com > temp.html

This works for both redirected output > /some/file, piped output | less and outputting directly to the terminal for me.

Update: Since curl 7.67.0 there is a new option --no-progress-meter which does precisely this and nothing else, see clonejo's answer for more details.

When you use 'badidea' or 'thisisunsafe' to bypass a Chrome certificate/HSTS error, does it only apply for the current site?

I'm a PHP developer and to be able to work on my development environment with a certificate, I was able to do the same by finding the real SSL HTTPS/HTTP Certificate and deleting it.

The steps are :

  1. In the address bar, type "chrome://net-internals/#hsts".
  2. Type the domain name in the text field below "Delete domain".
  3. Click the "Delete" button.
  4. Type the domain name in the text field below "Query domain".
  5. Click the "Query" button.
  6. Your response should be "Not found".

You can find more information at : http://classically.me/blogs/how-clear-hsts-settings-major-browsers

Although this solution is not the best, Chrome currently does not have any good solution for the moment. I have escalated this situation with their support team to help improve user experience.

Edit : you have to repeat the steps every time you will go on the production site.

How can I convert a PFX certificate file for use with Apache on a linux server?

To get it to work with Apache, we needed one extra step.

openssl pkcs12 -in domain.pfx -clcerts -nokeys -out domain.cer
openssl pkcs12 -in domain.pfx -nocerts -nodes  -out domain_encrypted.key
openssl rsa -in domain_encrypted.key -out domain.key

The final command decrypts the key for use with Apache. The domain.key file should look like this:

-----BEGIN RSA PRIVATE KEY-----
MjQxODIwNTFaMIG0MRQwEgYDVQQKEwtFbnRydXN0Lm5ldDFAMD4GA1UECxQ3d3d3
LmVudHJ1c3QubmV0L0NQU18yMDQ4IGluY29ycC4gYnkgcmVmLiAobGltaXRzIGxp
YWIuKTElMCMGA1UECxMcKGMpIDE5OTkgRW50cnVzdC5uZXQgTGltaXRlZDEzMDEG
A1UEAxMqRW50cnVzdC5uZXQgQ2VydGlmaWNhdGlvbiBBdXRob3JpdHkgKDIwNDgp
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEArU1LqRKGsuqjIAcVFmQq
-----END RSA PRIVATE KEY-----

Non-static variable cannot be referenced from a static context

I will try to explain the static thing to you. First of all static variables do not belong to any particular instance of the class. They are recognized with the name of the class. Static methods again do not belong again to any particular instance. They can access only static variables. Imagine you call MyClass.myMethod() and myMethod is a static method. If you use non-static variables inside the method, how the hell on earth would it know which variables to use? That's why you can use from static methods only static variables. I repeat again they do NOT belong to any particular instance.

Cast object to interface in TypeScript

Here's another way to force a type-cast even between incompatible types and interfaces where TS compiler normally complains:

export function forceCast<T>(input: any): T {

  // ... do runtime checks here

  // @ts-ignore <-- forces TS compiler to compile this as-is
  return input;
}

Then you can use it to force cast objects to a certain type:

import { forceCast } from './forceCast';

const randomObject: any = {};
const typedObject = forceCast<IToDoDto>(randomObject);

Note that I left out the part you are supposed to do runtime checks before casting for the sake of reducing complexity. What I do in my project is compiling all my .d.ts interface files into JSON schemas and using ajv to validate in runtime.

How to apply shell command to each line of a command output?

xargs fails with with backslashes, quotes. It needs to be something like

ls -1 |tr \\n \\0 |xargs -0 -iTHIS echo "THIS is a file."

xargs -0 option:

-0, --null
          Input  items are terminated by a null character instead of by whitespace, and the quotes and backslash are
          not special (every character is taken literally).  Disables the end of file string, which is treated  like
          any  other argument.  Useful when input items might contain white space, quote marks, or backslashes.  The
          GNU find -print0 option produces input suitable for this mode.

ls -1 terminates the items with newline characters, so tr translates them into null characters.

This approach is about 50 times slower than iterating manually with for ... (see Michael Aaron Safyans answer) (3.55s vs. 0.066s). But for other input commands like locate, find, reading from a file (tr \\n \\0 <file) or similar, you have to work with xargs like this.

Get a filtered list of files in a directory

import os

dir="/path/to/dir"
[x[0]+"/"+f for x in os.walk(dir) for f in x[2] if f.endswith(".jpg")]

This will give you a list of jpg files with their full path. You can replace x[0]+"/"+f with f for just filenames. You can also replace f.endswith(".jpg") with whatever string condition you wish.

JFrame background image

You can do:

setContentPane(new JLabel(new ImageIcon("resources/taverna.jpg")));

At first line of the Jframe class constructor, that works fine for me

How do I stop a program when an exception is raised in Python?

You can stop catching the exception, or - if you need to catch it (to do some custom handling), you can re-raise:

try:
  doSomeEvilThing()
except Exception, e:
  handleException(e)
  raise

Note that typing raise without passing an exception object causes the original traceback to be preserved. Typically it is much better than raise e.

Of course - you can also explicitly call

import sys 
sys.exit(exitCodeYouFindAppropriate)

This causes SystemExit exception to be raised, and (unless you catch it somewhere) terminates your application with specified exit code.

How to escape "&" in XML?

use &amp; in place of &

change to

<string name="magazine">Newspaper &amp; Magazines</string>

How to pause / sleep thread or process in Android?

One solution to this problem is to use the Handler.postDelayed() method. Some Google training materials suggest the same solution.

@Override
public void onClick(View v) {
    my_button.setBackgroundResource(R.drawable.icon);

    Handler handler = new Handler(); 
    handler.postDelayed(new Runnable() {
         @Override 
         public void run() { 
              my_button.setBackgroundResource(R.drawable.defaultcard); 
         } 
    }, 2000); 
}

However, some have pointed out that the solution above causes a memory leak because it uses a non-static inner and anonymous class which implicitly holds a reference to its outer class, the activity. This is a problem when the activity context is garbage collected.

A more complex solution that avoids the memory leak subclasses the Handler and Runnable with static inner classes inside the activity since static inner classes do not hold an implicit reference to their outer class:

private static class MyHandler extends Handler {}
private final MyHandler mHandler = new MyHandler();

public static class MyRunnable implements Runnable {
    private final WeakReference<Activity> mActivity;

    public MyRunnable(Activity activity) {
        mActivity = new WeakReference<>(activity);
    }

    @Override
    public void run() {
        Activity activity = mActivity.get();
        if (activity != null) {
            Button btn = (Button) activity.findViewById(R.id.button);
            btn.setBackgroundResource(R.drawable.defaultcard);
        }
    }
}

private MyRunnable mRunnable = new MyRunnable(this);

public void onClick(View view) {
    my_button.setBackgroundResource(R.drawable.icon);

    // Execute the Runnable in 2 seconds
    mHandler.postDelayed(mRunnable, 2000);
}

Note that the Runnable uses a WeakReference to the Activity, which is necessary in a static class that needs access to the UI.

How to $watch multiple variable change in angular

There is many way to watch multiple values :

//angular 1.1.4
$scope.$watchCollection(['foo', 'bar'], function(newValues, oldValues){
    // do what you want here
});

or more recent version

//angular 1.3
$scope.$watchGroup(['foo', 'bar'], function(newValues, oldValues, scope) {
  //do what you want here
});

Read official doc for more informations : https://docs.angularjs.org/api/ng/type/$rootScope.Scope

How to select distinct query using symfony2 doctrine query builder?

Just open your repository file and add this new function, then call it inside your controller:

 public function distinctCategories(){
        return $this->createQueryBuilder('cc')
        ->where('cc.contenttype = :type')
        ->setParameter('type', 'blogarticle')
        ->groupBy('cc.blogarticle')
        ->getQuery()
        ->getResult()
        ;
    }

Then within your controller:

public function index(YourRepository $repo)
{
    $distinctCategories = $repo->distinctCategories();


    return $this->render('your_twig_file.html.twig', [
        'distinctCategories' => $distinctCategories
    ]);
}

Good luck!

Select current element in jQuery

You will find the siblings() and parent() methods useful here.

// assuming A1 is clicked
$('div a').click(function(e) {
    $(this); // A1
    $(this).parent(); // the div containing A1
    $(this).siblings(); // A2 and A3
});

Combining those methods with andSelf() will let you manipulate any combination of those elements you want.

Edit: The comment left by Mark regarding event delegation on Shog9's answer is a very good one. The easiest way to accomplish this in jQuery would be by using the live() method.

// assuming A1 is clicked
$('div a').live('click', function(e) {
    $(this); // A1
    $(this).parent(); // the div containing A1
    $(this).siblings(); // A2 and A3
});

I think it actually binds the event to the root element, but the effect is that same. Not only is it more flexible, it also improves performance in a lot of cases. Just be sure to read the documentation to avoid any gotchas.

mysqldump & gzip commands to properly create a compressed file of a MySQL database using crontab

if you need to add a date-time to your backup file name (Centos7) use the following:

/usr/bin/mysqldump -u USER -pPASSWD DBNAME | gzip > ~/backups/db.$(date +%F.%H%M%S).sql.gz

this will create the file: db.2017-11-17.231537.sql.gz

"undefined" function declared in another file?

If you want to call a function from another go file and you are using Goland, then find the option 'Edit configuration' from the Run menu and change the run kind from File to Directory. It clears all the errors and allows you to call functions from other go files.

how to get the value of a textarea in jquery?

You can directly use

var message = $.trim($("#message").val());

Read more @ Get the Value of TextArea using the jQuery Val () Method

How to run python script with elevated privilege on windows

I can confirm that the solution by delphifirst works and is the easiest, simplest solution to the problem of running a python script with elevated privileges.

I created a shortcut to the python executable (python.exe) and then modified the shortcut by adding my script's name after the call to python.exe. Next I checked "run as administrator" on the "compatibility tab" of the shortcut. When the shortcut is executed, you get a prompt asking permission to run the script as an administrator.

My particular python application was an installer program. The program allows installing and uninstalling another python app. In my case I created two shortcuts, one named "appname install" and the other named "appname uninstall". The only difference between the two shortcuts is the argument following the python script name. In the installer version the argument is "install". In the uninstall version the argument is "uninstall". Code in the installer script evaluates the argument supplied and calls the appropriate function (install or uninstall) as needed.

I hope my explanation helps others more quickly figure out how to run a python script with elevated privileges.

jQuery If DIV Doesn't Have Class "x"

jQuery has the hasClass() function that returns true if any element in the wrapped set contains the specified class

if (!$(this).hasClass("selected")) {
    //do stuff
}

Take a look at my example of use

  • If you hover over a div, it fades as normal speed to 100% opacity if the div does not contain the 'selected' class
  • If you hover out of a div, it fades at slow speed to 30% opacity if the div does not contain the 'selected' class
  • Clicking the button adds 'selected' class to the red div. The fading effects no longer work on the red div

Here is the code for it

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.1/jquery.min.js"></script>
<title>Sandbox</title>
<meta http-equiv="Content-type" content="text/html; charset=utf-8" />
<style type="text/css" media="screen">
body { background-color: #FFF; font: 16px Helvetica, Arial; color: #000; }
</style>


<!-- jQuery code here -->
<script type="text/javascript">
$(function() {

$('#myButton').click(function(e) {
$('#div2').addClass('selected');
});

$('.thumbs').bind('click',function(e) { alert('You clicked ' + e.target.id ); } );

$('.thumbs').hover(fadeItIn, fadeItOut);


});

function fadeItIn(e) {
if (!$(e.target).hasClass('selected')) 
 { 
    $(e.target).fadeTo('normal', 1.0); 
  } 
}

function fadeItOut(e) { 
  if (!$(e.target).hasClass('selected'))
  { 
    $(e.target).fadeTo('slow', 0.3); 
 } 
}
</script>


</head>
<body>
<div id="div1" class="thumbs" style=" background-color: #0f0; margin: 10px; padding: 10px; width: 100px; height: 50px; clear: both;"> 
One div with a thumbs class
</div>
<div id="div2" class="thumbs" style=" background-color: #f00; margin: 10px; padding: 10px; width: 100px; height: 50px; clear: both;">
Another one with a thumbs class
</div>
<input type="button" id="myButton" value="add 'selected' class to red div" />
</body>
</html>

EDIT:

this is just a guess, but are you trying to achieve something like this?

  • Both divs start at 30% opacity
  • Hovering over a div fades to 100% opacity, hovering out fades back to 30% opacity. Fade effects only work on elements that don't have the 'selected' class
  • Clicking a div adds/removes the 'selected' class

jQuery Code is here-

$(function() {

$('.thumbs').bind('click',function(e) { $(e.target).toggleClass('selected'); } );
$('.thumbs').hover(fadeItIn, fadeItOut);
$('.thumbs').css('opacity', 0.3);

});

function fadeItIn(e) {
if (!$(e.target).hasClass('selected')) 
 { 
    $(e.target).fadeTo('normal', 1.0); 
  } 
}

function fadeItOut(e) { 
  if (!$(e.target).hasClass('selected'))
  { 
    $(e.target).fadeTo('slow', 0.3); 
 } 
}

<div id="div1" class="thumbs" style=" background-color: #0f0; margin: 10px; padding: 10px; width: 100px; height: 50px; clear: both; cursor:pointer;"> 
One div with a thumbs class
</div>
<div id="div2" class="thumbs" style=" background-color: #f00; margin: 10px; padding: 10px; width: 100px; height: 50px; clear: both; cursor:pointer;">
Another one with a thumbs class
</div>

Permission denied error while writing to a file in Python

This also happens when you attempt to create a file with the same name as a directory:

import os

conflict = 'conflict'

# Create a directory with a given name
try: 
    os.makedirs(conflict)
except OSError:
    if not os.path.isdir(conflict):
        raise

# Attempt to create a file with the same name
file = open(conflict, 'w+')

Result:

IOError: [Errno 13] Permission denied: 'conflict'

Get content of a cell given the row and column numbers

You don't need the CELL() part of your formulas:

=INDIRECT(ADDRESS(B1,B2))

or

=OFFSET($A$1, B1-1,B2-1)

will both work. Note that both INDIRECT and OFFSET are volatile functions. Volatile functions can slow down calculation because they are calculated at every single recalculation.

The remote end hung up unexpectedly while git cloning

Obs.: Changing http.postBuffer might also require to set up the Nginx configuration file for gitlab to accept larger body sizes for the client, by tuning the value of client_max_body_size.

However, there is a workaround if you have access to the Gitlab machine or to a machine in its network, and that is by making use of git bundle.

  1. go to your git repository on the source machine
  2. run git bundle create my-repo.bundle --all
  3. transfer (eg., with rsync) the my-repo.bundle file to the destination machine
  4. on the destination machine, run git clone my-repo.bundle
  5. git remote set-url origin "path/to/your/repo.git"
  6. git push

All the best!

Resizable table columns with jQuery

Here's a short complete html example. See demo http://jsfiddle.net/CU585/

<!DOCTYPE html><html><head><title>resizable columns</title>
<meta charset="utf-8">
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.11.0/themes/smoothness/jquery-ui.css" />
<script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.11.0/jquery-ui.min.js"></script>
<style>
th {border: 1px solid black;}
table{border-collapse: collapse;}
.ui-icon, .ui-widget-content .ui-icon {background-image: none;}
</style>
<body>
<table>
<tr><th>head 1</th><th>head 2</th></tr><tr><td>a1</td><td>b1</td></tr></table><script>
$( "th" ).resizable();
</script></body></html>

How to show all shared libraries used by executables in Linux?

on ubuntu print packages related to an executable

ldd executable_name|awk '{print $3}'|xargs dpkg -S |awk -F  ":"  '{print $1}'

What is the recommended way to make a numeric TextField in JavaFX?

Starting from Java SE 8u40, for such need you can use an "integer" Spinner allowing to safely select a valid integer by using the keyboard's up arrow/down arrow keys or the up arrow/down arrow provided buttons.

You can also define a min, a max and an initial value to limit the allowed values and an amount to increment or decrement by, per step.

For example

// Creates an integer spinner with 1 as min, 10 as max and 2 as initial value
Spinner<Integer> spinner1 = new Spinner<>(1, 10, 2);
// Creates an integer spinner with 0 as min, 100 as max and 10 as initial 
// value and 10 as amount to increment or decrement by, per step
Spinner<Integer> spinner2 = new Spinner<>(0, 100, 10, 10);

Example of result with an "integer" spinner and a "double" spinner

enter image description here

A spinner is a single-line text field control that lets the user select a number or an object value from an ordered sequence of such values. Spinners typically provide a pair of tiny arrow buttons for stepping through the elements of the sequence. The keyboard's up arrow/down arrow keys also cycle through the elements. The user may also be allowed to type a (legal) value directly into the spinner. Although combo boxes provide similar functionality, spinners are sometimes preferred because they don't require a drop-down list that can obscure important data, and also because they allow for features such as wrapping from the maximum value back to the minimum value (e.g., from the largest positive integer to 0).

More details about the Spinner control

What are Maven goals and phases and what is their difference?

There are following three built-in build lifecycles:

  • default
  • clean
  • site

Lifecycle default -> [validate, initialize, generate-sources, process-sources, generate-resources, process-resources, compile, process-classes, generate-test-sources, process-test-sources, generate-test-resources, process-test-resources, test-compile, process-test-classes, test, prepare-package, package, pre-integration-test, integration-test, post-integration-test, verify, install, deploy]

Lifecycle clean -> [pre-clean, clean, post-clean]

Lifecycle site -> [pre-site, site, post-site, site-deploy]

The flow is sequential, for example, for default lifecycle, it starts with validate, then initialize and so on...

You can check the lifecycle by enabling debug mode of mvn i.e., mvn -X <your_goal>

In Python, when to use a Dictionary, List or Set?

Lists are what they seem - a list of values. Each one of them is numbered, starting from zero - the first one is numbered zero, the second 1, the third 2, etc. You can remove values from the list, and add new values to the end. Example: Your many cats' names.

Tuples are just like lists, but you can't change their values. The values that you give it first up, are the values that you are stuck with for the rest of the program. Again, each value is numbered starting from zero, for easy reference. Example: the names of the months of the year.

Dictionaries are similar to what their name suggests - a dictionary. In a dictionary, you have an 'index' of words, and for each of them a definition. In python, the word is called a 'key', and the definition a 'value'. The values in a dictionary aren't numbered - tare similar to what their name suggests - a dictionary. In a dictionary, you have an 'index' of words, and for each of them a definition. In python, the word is called a 'key', and the definition a 'value'. The values in a dictionary aren't numbered - they aren't in any specific order, either - the key does the same thing. You can add, remove, and modify the values in dictionaries. Example: telephone book.

How do you stash an untracked file?

I thought this could be solved by telling git that the file exists, rather than committing all of the contents of it to the staging area, and then call git stash. Araqnid describes how to do the former.

git add --intent-to-add path/to/untracked-file

or

git update-index --add --cacheinfo 100644 e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 path/to/untracked-file

However, the latter doesn't work:

$ git stash
b.rb: not added yet
fatal: git-write-tree: error building trees
Cannot save the current index state

How do I change TextView Value inside Java Code?

I presume that this question is a continuation of this one.

What are you trying to do? Do you really want to dynamically change the text in your TextView objects when the user clicks a button? You can certainly do that, if you have a reason, but, if the text is static, it is usually set in the main.xml file, like this:

<TextView  
android:id="@+id/rate"
android:layout_width="fill_parent" 
android:layout_height="wrap_content" 
android:text="@string/rate"
/>

The string "@string/rate" refers to an entry in your strings.xml file that looks like this:

<string name="rate">Rate</string>

If you really want to change this text later, you can do so by using Nikolay's example - you'd get a reference to the TextView by utilizing the id defined for it within main.xml, like this:


final TextView textViewToChange = (TextView) findViewById(R.id.rate);
textViewToChange.setText(
    "The new text that I'd like to display now that the user has pushed a button.");

Html.EditorFor Set Default Value

Its not right to set default value in View. The View should perform display work, not more. This action breaks ideology of MVC pattern. So the right place to set defaults - create method of controller class.

Efficient SQL test query or validation query that will work across all (or most) databases

For MSSQL.

This helped me determine if linked servers were alive. Using an Open Query connection and a TRY CATCH to put the results of the error to something useful.

IF OBJECT_ID('TEMPDB..#TEST_CONNECTION') IS NOT NULL DROP TABLE #TEST_CONNECTION
IF OBJECT_ID('TEMPDB..#RESULTSERROR') IS NOT NULL DROP TABLE #RESULTSERROR
IF OBJECT_ID('TEMPDB..#RESULTSGOOD') IS NOT NULL DROP TABLE #RESULTSGOOD

DECLARE @LINKEDSERVER AS VARCHAR(25)    SET @LINKEDSERVER = 'SERVER NAME GOES HERE'
DECLARE @SQL AS VARCHAR(MAX)
DECLARE @OPENQUERY AS VARCHAR(MAX)

--IF OBJECT_ID ('dbo.usp_GetErrorInfo', 'P' ) IS NOT NULL DROP PROCEDURE usp_GetErrorInfo;  
--GO  

---- Create procedure to retrieve error information.  
--CREATE PROCEDURE dbo.usp_GetErrorInfo  
--AS  
--SELECT     
--    ERROR_NUMBER() AS ErrorNumber  
--    ,ERROR_SEVERITY() AS ErrorSeverity  
--    ,ERROR_STATE() AS ErrorState  
--    ,ERROR_PROCEDURE() AS ErrorProcedure  
--    ,ERROR_LINE() AS ErrorLine  
--    ,ERROR_MESSAGE() AS Message;  
--GO  


BEGIN TRY
SET @SQL='
SELECT 1 
'''
--SELECT @SQL
SET @OPENQUERY = 'SELECT * INTO ##TEST_CONNECTION FROM OPENQUERY(['+ @LINKEDSERVER +'],''' + @SQL + ')'
--SELECT @OPENQUERY
EXEC(@OPENQUERY)
SELECT * INTO #TEST_CONNECTION FROM ##TEST_CONNECTION
DROP TABLE ##TEST_CONNECTION
--SELECT * FROM #TEST_CONNECTION
END TRY

BEGIN CATCH
-- Execute error retrieval routine.
IF OBJECT_ID('dbo.usp_GetErrorInfo') IS NOT NULL -- IT WILL ALWAYS HAVE SOMTHING... 
    BEGIN
        CREATE TABLE #RESULTSERROR (
        [ErrorNumber]       INT
        ,[ErrorSeverity]    INT
        ,[ErrorState]       INT
        ,[ErrorProcedure]   INT
        ,[ErrorLine]        INT
        ,[Message]          NVARCHAR(MAX) 
        )
        INSERT INTO #RESULTSERROR
        EXECUTE dbo.usp_GetErrorInfo
    END
END CATCH

BEGIN 
    IF (Select ERRORNUMBER FROM #RESULTSERROR WHERE ERRORNUMBER = '1038') IS NOT NULL --'1038' FOR ME SHOWED A CONNECTION ATLEAST. 
        SELECT
        '0' AS [ErrorNumber]        
        ,'0'AS [ErrorSeverity]  
        ,'0'AS [ErrorState]     
        ,'0'AS [ErrorProcedure] 
        ,'0'AS [ErrorLine]      
        , CONCAT('CONNECTION IS UP ON ', @LINKEDSERVER) AS [Message]            
    ELSE 
        SELECT * FROM #RESULTSERROR
END

docs.microsoft.com

How to compare a local git branch with its remote branch?

try:

git diff origin HEAD

Assuming you want to diff you current Local branch's HEAD against the origin. And assuming you are on the local branch. :)

POST JSON to API using Rails and HTTParty

The :query_string_normalizer option is also available, which will override the default normalizer HashConversions.to_params(query)

query_string_normalizer: ->(query){query.to_json}

How do I get a value of a <span> using jQuery?

$('#id span').text() is the answer!

jQuery callback on image load (even when the image is cached)

I can give you a little tip if you want do like this:

<div style="position:relative;width:100px;height:100px">
     <img src="loading.jpg" style='position:absolute;width:100px;height:100px;z-index:0'/>
     <img onLoad="$(this).fadeIn('normal').siblings('img').fadeOut('normal')" src="picture.jpg" style="display:none;position:absolute;width:100px;height:100px;z-index:1"/>
</div>

If you do that when the browser caches pictures, it's no problem always img shown but loading img under real picture.

how to open *.sdf files?

It's a SQL Compact database. You need to define what you mean by "Open". You can open it via code with the SqlCeConnection so you can write your own tool/app to access it.

Visual Studio can also open the files directly if was created with the right version of SQL Compact.

There are also some third-party tools for manipulating them.

How can I plot a histogram such that the heights of the bars sum to 1 in matplotlib?

Here is another simple solution using np.histogram() method.

myarray = np.random.random(100)
results, edges = np.histogram(myarray, normed=True)
binWidth = edges[1] - edges[0]
plt.bar(edges[:-1], results*binWidth, binWidth)

You can indeed check that the total sums up to 1 with:

> print sum(results*binWidth)
1.0

Python JSON dump / append to .txt with each variable on new line

Your question is a little unclear. If you're generating hostDict in a loop:

with open('data.txt', 'a') as outfile:
    for hostDict in ....:
        json.dump(hostDict, outfile)
        outfile.write('\n')

If you mean you want each variable within hostDict to be on a new line:

with open('data.txt', 'a') as outfile:
    json.dump(hostDict, outfile, indent=2)

When the indent keyword argument is set it automatically adds newlines.

How to retrieve GET parameters from JavaScript

tl;dr solution on a single line of code using vanilla JavaScript

var queryDict = {}
location.search.substr(1).split("&").forEach(function(item) {queryDict[item.split("=")[0]] = item.split("=")[1]})

This is the simplest solution. It unfortunately does not handle multi-valued keys and encoded characters.

"?a=1&a=%2Fadmin&b=2&c=3&d&e"
> queryDict
a: "%2Fadmin"  // Overridden with the last value, not decoded.
b: "2"
c: "3"
d: undefined
e: undefined

Multi-valued keys and encoded characters?

See the original answer at How can I get query string values in JavaScript?.

"?a=1&b=2&c=3&d&e&a=5&a=t%20e%20x%20t&e=http%3A%2F%2Fw3schools.com%2Fmy%20test.asp%3Fname%3Dståle%26car%3Dsaab&a=%2Fadmin"
> queryDict
a: ["1", "5", "t e x t", "/admin"]
b: ["2"]
c: ["3"]
d: [undefined]
e: [undefined, "http://w3schools.com/my test.asp?name=ståle&car=saab"]

In your example, you would access the value like this:

"?returnurl=%2Fadmin"
> qd.returnurl    // ["/admin"]
> qd['returnurl'] // ["/admin"]
> qd.returnurl[0] // "/admin"

Check if cookie exists else set cookie to Expire in 10 days

You need to read and write document.cookie

if (document.cookie.indexOf("visited=") >= 0) {
  // They've been here before.
  alert("hello again");
}
else {
  // set a new cookie
  expiry = new Date();
  expiry.setTime(expiry.getTime()+(10*60*1000)); // Ten minutes

  // Date()'s toGMTSting() method will format the date correctly for a cookie
  document.cookie = "visited=yes; expires=" + expiry.toGMTString();
  alert("this is your first time");
}

Enable ASP.NET ASMX web service for HTTP POST / GET requests

Actually, I found a somewhat quirky way to do this. Add the protocol to your web.config, but inside a location element. Specify the webservice location as the path attribute, like so:

<location path="YourWebservice.asmx">
  <system.web>
    <webServices>
      <protocols>
        <add name="HttpGet"/>
        <add name="HttpPost"/>
      </protocols>
    </webServices>
  </system.web>
</location>

What SOAP client libraries exist for Python, and where is the documentation for them?

Could this help: http://users.skynet.be/pascalbotte/rcx-ws-doc/python.htm#SOAPPY

I found it by searching for wsdl and python, with the rational being, that you would need a wsdl description of a SOAP server to do any useful client wrappers....

Submit button doesn't work

I faced this problem today, and the issue was I was preventing event default action in document onclick:

document.onclick = function(e) {
    e.preventDefault();
}

Document onclick usually is used for event delegation but it's wrong to prevent default for every event, you must do it only for required elements:

document.onclick = function(e) {
    if (e.target instanceof HTMLAnchorElement) e.preventDefault();
}

How can I set the color of a selected row in DataGrid

As an extention to @Seb Kade's answer, you can fully control the colours of the selected and unselected rows using the following Style:

<Style TargetType="{x:Type DataGridRow}">
    <Style.Resources>
        <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="Transparent" />
        <SolidColorBrush x:Key="{x:Static SystemColors.ControlBrushKey}" Color="Transparent" />
        <SolidColorBrush x:Key="{x:Static SystemColors.HighlightTextBrushKey}" Color="Black" />
        <SolidColorBrush x:Key="{x:Static SystemColors.ControlTextBrushKey}" Color="Black" />
    </Style.Resources>
</Style>

You can of course enter whichever colours you prefer. This Style will also work for other collection items such as ListBoxItems (if you replace TargetType="{x:Type DataGridRow}" with TargetType="{x:Type ListBoxItem}" for instance).

Python equivalent to 'hold on' in Matlab

The hold on feature is switched on by default in matplotlib.pyplot. So each time you evoke plt.plot() before plt.show() a drawing is added to the plot. Launching plt.plot() after the function plt.show() leads to redrawing the whole picture.

JavaScript isset() equivalent

(typeof SOMETHING) !== 'undefined'

It's too long to write when used. But we can't package the typeof keyword into a function, because an error will thrown before the function is called, like this:

function isdef($var) {
    return (typeof $var) !== 'undefined';
}

isdef(SOMETHING); ///// thrown error: SOMETHING is not defined

So I figured out a way:

function isdef($type) {
    return $type !== 'undefined';
}

isdef(typeof SOMETHING);

It can work both with individual variables (variables that does not exist at all), or object properties (non-existent properties). And only 7 more characters than PHP isset.

How do I replace text in a selection?

I know this has been answered many times, and all are correct, but I though I would add another:

Similar to the Ctrl - D method to select individual occurrences of the current selection, you can select all occurrences in the file with Alt+F3 when using Windows or Linux (CMD+CTRL+G in Mac world).

This is helpful for mass-changes.

How to export a table dataframe in PySpark to csv?

If data frame fits in a driver memory and you want to save to local files system you can convert Spark DataFrame to local Pandas DataFrame using toPandas method and then simply use to_csv:

df.toPandas().to_csv('mycsv.csv')

Otherwise you can use spark-csv:

  • Spark 1.3

    df.save('mycsv.csv', 'com.databricks.spark.csv')
    
  • Spark 1.4+

    df.write.format('com.databricks.spark.csv').save('mycsv.csv')
    

In Spark 2.0+ you can use csv data source directly:

df.write.csv('mycsv.csv')

How can I pass selected row to commandLink inside dataTable or ui:repeat?

In my view page:

<p:dataTable  ...>
<p:column>
<p:commandLink actionListener="#{inquirySOController.viewDetail}" 
               process="@this" update=":mainform:dialog_content"
           oncomplete="dlg2.show()">
    <h:graphicImage library="images" name="view.png"/>
    <f:param name="trxNo" value="#{item.map['trxNo']}"/>
</p:commandLink>
</p:column>
</p:dataTable>

backing bean

 public void viewDetail(ActionEvent e) {

    String trxNo = getFacesContext().getRequestParameterMap().get("trxNo");

    for (DTO item : list) {
        if (item.get("trxNo").toString().equals(trxNo)) {
            System.out.println(trxNo);
            setSelectedItem(item);
            break;
        }
    }
}

What is the difference between Java RMI and RPC?

RMI or Remote Method Invokation is very similar to RPC or Remote Procedure call in that the client both send proxy objects (or stubs) to the server however the subtle difference is that client side RPC invokes FUNCTIONS through the proxy function and RMI invokes METHODS through the proxy function. RMI is considered slightly superior as it is an object-oriented version of RPC.

From here.

For more information and examples, have a look here.

How to add headers to a multicolumn listbox in an Excel userform using VBA

Here's one approach which automates creating labels above each column of a listbox (on a worksheet).

It will work (though not super-pretty!) as long as there's no horizontal scrollbar on your listbox.

Sub Tester()
Dim i As Long

With Me.lbTest
    .Clear
    .ColumnCount = 5
    'must do this next step!
    .ColumnWidths = "70;60;100;60;60"
    .ListStyle = fmListStylePlain
    Debug.Print .ColumnWidths
    For i = 0 To 10
        .AddItem
        .List(i, 0) = "blah" & i
        .List(i, 1) = "blah"
        .List(i, 2) = "blah"
        .List(i, 3) = "blah"
        .List(i, 4) = "blah"
    Next i

End With

LabelHeaders Me.lbTest, Array("Header1", "Header2", _
                     "Header3", "Header4", "Header5")

End Sub

Sub LabelHeaders(lb, arrHeaders)

    Const LBL_HT As Long = 15
    Dim T, L, shp As Shape, cw As String, arr
    Dim i As Long, w

    'delete any previous headers for this listbox
    For i = lb.Parent.Shapes.Count To 1 Step -1
        If lb.Parent.Shapes(i).Name Like lb.Name & "_*" Then
            lb.Parent.Shapes(i).Delete
        End If
    Next i

    'get an array of column widths
    cw = lb.ColumnWidths
    If Len(cw) = 0 Then Exit Sub
    cw = Replace(cw, " pt", "")
    arr = Split(cw, ";")

    'start points for labels
    T = lb.Top - LBL_HT
    L = lb.Left

    For i = LBound(arr) To UBound(arr)
        w = CLng(arr(i))
        If i = UBound(arr) And (L + w) < lb.Width Then w = lb.Width - L
        Set shp = ActiveSheet.Shapes.AddShape(msoShapeRectangle, _
                                         L, T, w, LBL_HT)
        With shp
            .Name = lb.Name & "_" & i
            'do some formatting
            .Line.ForeColor.RGB = vbBlack
            .Line.Weight = 1
            .Fill.ForeColor.RGB = RGB(220, 220, 220)
            .TextFrame2.TextRange.Characters.Text = arrHeaders(i)
            .TextFrame2.TextRange.Font.Size = 9
            .TextFrame2.TextRange.Font.Fill.ForeColor.RGB = vbBlack
        End With
        L = L + w
    Next i
End Sub

CURRENT_DATE/CURDATE() not working as default DATE value

create table the_easy_way(
  capture_ts DATETIME DEFAULT CURRENT_TIMESTAMP,
  capture_dt DATE AS (DATE(capture_ts))
)

(MySQL 5.7)

How to build a 2 Column (Fixed - Fluid) Layout with Twitter Bootstrap?

- Another Update -

Since Twitter Bootstrap version 2.0 - which saw the removal of the .container-fluid class - it has not been possible to implement a two column fixed-fluid layout using just the bootstrap classes - however I have updated my answer to include some small CSS changes that can be made in your own CSS code that will make this possible

It is possible to implement a fixed-fluid structure using the CSS found below and slightly modified HTML code taken from the Twitter Bootstrap Scaffolding : layouts documentation page:

HTML

<div class="container-fluid fill">
    <div class="row-fluid">
        <div class="fixed">  <!-- we want this div to be fixed width -->
            ...
        </div>
        <div class="hero-unit filler">  <!-- we have removed spanX class -->
            ...
        </div>
    </div>
</div>

CSS

/* CSS for fixed-fluid layout */

.fixed {
    width: 150px;  /* the fixed width required */
    float: left;
}

.fixed + div {
     margin-left: 150px;  /* must match the fixed width in the .fixed class */
     overflow: hidden;
}


/* CSS to ensure sidebar and content are same height (optional) */

html, body {
    height: 100%;
}

.fill { 
    min-height: 100%;
    position: relative;
}

.filler:after{
    background-color:inherit;
    bottom: 0;
    content: "";
    height: auto;
    min-height: 100%;
    left: 0;
    margin:inherit;
    right: 0;
    position: absolute;
    top: 0;
    width: inherit;
    z-index: -1;  
}

I have kept the answer below - even though the edit to support 2.0 made it a fluid-fluid solution - as it explains the concepts behind making the sidebar and content the same height (a significant part of the askers question as identified in the comments)


Important

Answer below is fluid-fluid

Update As pointed out by @JasonCapriotti in the comments, the original answer to this question (created for v1.0) did not work in Bootstrap 2.0. For this reason, I have updated the answer to support Bootstrap 2.0

To ensure that the main content fills at least 100% of the screen height, we need to set the height of the html and body to 100% and create a new css class called .fill which has a minimum-height of 100%:

html, body {
    height: 100%;
}

.fill { 
    min-height: 100%;
}

We can then add the .fill class to any element that we need to take up 100% of the sceen height. In this case we add it to the first div:

<div class="container-fluid fill">
    ...
</div>

To ensure that the Sidebar and the Content columns have the same height is very difficult and unnecessary. Instead we can use the ::after pseudo selector to add a filler element that will give the illusion that the two columns have the same height:

.filler::after {
    background-color: inherit;
    bottom: 0;
    content: "";
    right: 0;
    position: absolute;
    top: 0;
    width: inherit;
    z-index: -1;  
}

To make sure that the .filler element is positioned relatively to the .fill element we need to add position: relative to .fill:

.fill { 
    min-height: 100%;
    position: relative;
}

And finally add the .filler style to the HTML:

HTML

<div class="container-fluid fill">
    <div class="row-fluid">
        <div class="span3">
            ...
        </div>
        <div class="span9 hero-unit filler">
            ...
        </div>
    </div>
</div>

Notes

  • If you need the element on the left of the page to be the filler then you need to change right: 0 to left: 0.

ReactJS - Call One Component Method From Another Component

Well, actually, React is not suitable for calling child methods from the parent. Some frameworks, like Cycle.js, allow easily access data both from parent and child, and react to it.

Also, there is a good chance you don't really need it. Consider calling it into existing component, it is much more independent solution. But sometimes you still need it, and then you have few choices:

  • Pass method down, if it is a child (the easiest one, and it is one of the passed properties)
  • add events library; in React ecosystem Flux approach is the most known, with Redux library. You separate all events into separated state and actions, and dispatch them from components
  • if you need to use function from the child in a parent component, you can wrap in a third component, and clone parent with augmented props.

UPD: if you need to share some functionality which doesn't involve any state (like static functions in OOP), then there is no need to contain it inside components. Just declare it separately and invoke when need:

let counter = 0;
function handleInstantiate() {
   counter++;
}

constructor(props) {
   super(props);
   handleInstantiate();
}

IsNull function in DB2 SQL?

I think COALESCE function partially similar to the isnull, but try it.

Why don't you go for null handling functions through application programs, it is better alternative.

How can I make one python file run another?

I used subprocess.call it's almost same like subprocess.Popen

from subprocess import call
call(["python", "your_file.py"])

Optimal way to DELETE specified rows from Oracle

First, disabling the index during the deletion would be helpful.

Try with a MERGE INTO statement :
1) create a temp table with IDs and an additional column from TABLE1 and test with the following

MERGE INTO table1 src
USING (SELECT id,col1
         FROM test_merge_delete) tgt
ON (src.id = tgt.id)
WHEN MATCHED THEN
  UPDATE
     SET src.col1 = tgt.col1
  DELETE
   WHERE src.id = tgt.id

Difference between @Mock and @InjectMocks

  • @Mock creates a mock implementation for the classes you need.
  • @InjectMock creates an instance of the class and injects the mocks that are marked with the annotations @Mock into it.

For example

@Mock
StudentDao studentDao;

@InjectMocks
StudentService service;

@Before
public void setUp() throws Exception {
    MockitoAnnotations.initMocks(this);
}

Here we need the DAO class for the service class. So, we mock it and inject it in the service class instance. Similarly, in Spring framework all the @Autowired beans can be mocked by @Mock in jUnits and injected into your bean through @InjectMocks.

MockitoAnnotations.initMocks(this) method initialises these mocks and injects them for every test method so it needs to be called in the setUp() method.

This link has a good tutorial for Mockito framework

You seem to not be depending on "@angular/core". This is an error

**You should be in the newly created YOUR_APP folder before you hit the ng serve command **

Lets start from fresh,

1) install npm

2) create a new angular app ( ng new <YOUR_APP_NAME> )

3) go to app folder (cd YOUR_APP_NAME)

4) ng serve

I hope it will resolve the issue.

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

I wrote a higher order function to make it work right. We've used this in several projects and it seems to work great. This is how things should have been done from the start, without the "using" paradigm or so on.

TReturn UseService<TChannel, TReturn>(Func<TChannel, TReturn> code)
{
    var chanFactory = GetCachedFactory<TChannel>();
    TChannel channel = chanFactory.CreateChannel();
    bool error = true;
    try {
        TReturn result = code(channel);
        ((IClientChannel)channel).Close();
        error = false;
        return result;
    }
    finally {
        if (error) {
            ((IClientChannel)channel).Abort();
        }
    }
}

You can make calls like this:

int a = 1;
int b = 2;
int sum = UseService((ICalculator calc) => calc.Add(a, b));
Console.WriteLine(sum);

This is pretty much just like you have in your example. In some projects, we write strongly typed helper methods, so we end up writing things like "Wcf.UseFooService(f=>f...)".

I find it quite elegant, all things considered. Is there a particular problem you encountered?

This allows other nifty features to be plugged in. For instance, on one site, the site authenticates to the service on behalf of the logged in user. (The site has no credentials by itself.) By writing our own "UseService" method helper, we can configure the channel factory the way we want, etc. We're also not bound to using the generated proxies -- any interface will do.

Get list of all input objects using JavaScript, without accessing a form object

querySelectorAll returns a NodeList which has its own forEach method:

document.querySelectorAll('input').forEach( input => {
  // ...
});

getElementsByTagName now returns an HTMLCollection instead of a NodeList. So you would first need to convert it to an array to have access to methods like map and forEach:

Array.from(document.getElementsByTagName('input')).forEach( input => {
  // ...
});

Div with horizontal scrolling only

I couldn't get the selected answer to work but after a bit of research, I found that the horizontal scrolling div must have white-space: nowrap in the css.

Here's complete working code:

<!doctype html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <title>Something</title>
    <style type="text/css">
        #scrolly{
            width: 1000px;
            height: 190px;
            overflow: auto;
            overflow-y: hidden;
            margin: 0 auto;
            white-space: nowrap
        }

        img{
            width: 300px;
            height: 150px;
            margin: 20px 10px;
            display: inline;
        }
    </style>
</head>
<body>
    <div id='scrolly'>
        <img src='img/car.jpg'></img>
        <img src='img/car.jpg'></img>
        <img src='img/car.jpg'></img>
        <img src='img/car.jpg'></img>
        <img src='img/car.jpg'></img>
        <img src='img/car.jpg'></img>
    </div>
</body>
</html>

no module named zlib

After running configure, you can change the config option in the file Modules/Setup as below:

zlib zlibmodule.c -I$(prefix)/include -L$(exec_prefix)/lib -lz

Or you can uncomment the zlib line as-is.

Convert String to Date in MS Access Query

In Access, click Create > Module and paste in the following code

Public Function ConvertMyStringToDateTime(strIn As String) As Date
ConvertMyStringToDateTime = CDate( _
        Mid(strIn, 1, 4) & "-" & Mid(strIn, 5, 2) & "-" & Mid(strIn, 7, 2) & " " & _
        Mid(strIn, 9, 2) & ":" & Mid(strIn, 11, 2) & ":" & Mid(strIn, 13, 2))
End Function

Hit Ctrl+S and save the module as modDateConversion.

Now try using a query like

Select * from Events
Where Events.[Date] > ConvertMyStringToDateTime("20130423014854")

--- Edit ---

Alternative solution avoiding user-defined VBA function:

SELECT * FROM Events
WHERE Format(Events.[Date],'yyyyMMddHhNnSs') > '20130423014854'

Update Row if it Exists Else Insert Logic with Entity Framework

Check existing row with Any.

    public static void insertOrUpdateCustomer(Customer customer)
    {
        using (var db = getDb())
        {

            db.Entry(customer).State = !db.Customer.Any(f => f.CustomerId == customer.CustomerId) ? EntityState.Added : EntityState.Modified;
            db.SaveChanges();

        }

    }

Store images in a MongoDB database

var upload = multer({dest: "./uploads"});
var mongo = require('mongodb');
var Grid = require("gridfs-stream");
Grid.mongo = mongo;

router.post('/:id', upload.array('photos', 200), function(req, res, next){
gfs = Grid(db);
var ss = req.files;
   for(var j=0; j<ss.length; j++){
     var originalName = ss[j].originalname;
     var filename = ss[j].filename;
     var writestream = gfs.createWriteStream({
         filename: originalName
     });
    fs.createReadStream("./uploads/" + filename).pipe(writestream);
   }
});

In your view:

<form action="/" method="post" enctype="multipart/form-data">
<input type="file" name="photos">

With this code you can add single as well as multiple images in MongoDB.

How to prevent errno 32 broken pipe?

Your server process has received a SIGPIPE writing to a socket. This usually happens when you write to a socket fully closed on the other (client) side. This might be happening when a client program doesn't wait till all the data from the server is received and simply closes a socket (using close function).

In a C program you would normally try setting to ignore SIGPIPE signal or setting a dummy signal handler for it. In this case a simple error will be returned when writing to a closed socket. In your case a python seems to throw an exception that can be handled as a premature disconnect of the client.

JavaScript - Get Portion of URL Path

There is a useful Web API method called URL

_x000D_
_x000D_
const url = new URL('http://www.somedomain.com/account/search?filter=a#top');_x000D_
console.log(url.pathname.split('/'));_x000D_
const params = new URLSearchParams(url.search)_x000D_
console.log(params.get("filter"))
_x000D_
_x000D_
_x000D_

How to convert a String to a Date using SimpleDateFormat?

Try this:

new SimpleDateFormat("MM/dd/yyyy")
  • MM is "month" (not mm)
  • dd is "day" (not DD)

It's all in the javadoc for SimpleDateFormat


FYI, the reason your format is still a valid date format is that:

  • mm is "minutes"
  • DD is "day in year"

Also, you don't need the cast to Date... it already is a Date (or it explodes):

public static void main(String[] args) throws ParseException {
    System.out.println(new SimpleDateFormat("MM/dd/yyyy").parse("08/16/2011"));
}

Output:

Tue Aug 16 00:00:00 EST 2011

Voila!

How to restart kubernetes nodes?

I had an onpremises HA installation, a master and a worker stopped working returning a NOTReady status. Checking the kubelet logs on the nodes I found out this problem:

failed to run Kubelet: Running with swap on is not supported, please disable swap! or set --fail-swap-on flag to false

Disabling swap on nodes with

swapoff -a

and restarting the kubelet

systemctl restart kubelet

did the work.

WampServer: php-win.exe The program can't start because MSVCR110.dll is missing

What solves my problem: I am using 64 bit Windows 7, so I thought I could install 64 bit Wamp. After I Installed the 32-bit version the error does not appear. So something in the developing process at Wamp went wrong...

How to set adaptive learning rate for GradientDescentOptimizer?

Tensorflow provides an op to automatically apply an exponential decay to a learning rate tensor: tf.train.exponential_decay. For an example of it in use, see this line in the MNIST convolutional model example. Then use @mrry's suggestion above to supply this variable as the learning_rate parameter to your optimizer of choice.

The key excerpt to look at is:

# Optimizer: set up a variable that's incremented once per batch and
# controls the learning rate decay.
batch = tf.Variable(0)

learning_rate = tf.train.exponential_decay(
  0.01,                # Base learning rate.
  batch * BATCH_SIZE,  # Current index into the dataset.
  train_size,          # Decay step.
  0.95,                # Decay rate.
  staircase=True)
# Use simple momentum for the optimization.
optimizer = tf.train.MomentumOptimizer(learning_rate,
                                     0.9).minimize(loss,
                                                   global_step=batch)

Note the global_step=batch parameter to minimize. That tells the optimizer to helpfully increment the 'batch' parameter for you every time it trains.

Python: How to use RegEx in an if statement?

The REPL makes it easy to learn APIs. Just run python, create an object and then ask for help:

$ python
>>> import re
>>> help(re.compile(r''))

at the command line shows, among other things:

search(...)

search(string[, pos[, endpos]]) --> match object or None. Scan through string looking for a match, and return a corresponding MatchObject instance. Return None if no position in the string matches.

so you can do

regex = re.compile(regex_txt, re.IGNORECASE)

match = regex.search(content)  # From your file reading code.
if match is not None:
  # use match

Incidentally,

regex_txt = "facebook.com"

has a . which matches any character, so re.compile("facebook.com").search("facebookkcom") is not None is true because . matches any character. Maybe

regex_txt = r"(?i)facebook\.com"

The \. matches a literal "." character instead of treating . as a special regular expression operator.

The r"..." bit means that the regular expression compiler gets the escape in \. instead of the python parser interpreting it.

The (?i) makes the regex case-insensitive like re.IGNORECASE but self-contained.

iPhone hide Navigation Bar only on first page

The currently accepted answer does not match the intended behavior described in the question. The question asks for the navigation bar to be hidden on the root view controller, but visible everywhere else, but the accepted answer hides the navigation bar on a particular view controller. What happens when another instance of the first view controller is pushed onto the stack? It will hide the navigation bar even though we are not looking at the root view controller.

Instead, @Chad M.'s strategy of using the UINavigationControllerDelegate is a good one, and here is a more complete solution. Steps:

  1. Subclass UINavigationController
  2. Implement the -navigationController:willShowViewController:animated method to show or hide the navigation bar based on whether it is showing the root view controller
  3. Override the initialization methods to set the UINavigationController subclass as its own delegate

Complete code for this solution can be found in this Gist. Here's the navigationController:willShowViewController:animated implementation:

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    /* Hide navigation bar if root controller */
    if ([viewController isEqual:[self.viewControllers firstObject]]) {
        [self setNavigationBarHidden:YES animated:animated];
    } else {
        [self setNavigationBarHidden:NO animated:animated];
    }
}

Bootstrap modal not displaying

I had the same problem.

Solution: I put modal's DIV in the uppermost scope of main HTML (due to using Jinja2 blocks my modal got nested somewhere in the middle of some other DIV.

What to do about Eclipse's "No repository found containing: ..." error messages?

The updates that Eclipse has found have dependencies that need to be downloaded during the installation but which cannot currently be found. This may be a temporary network problem or some repo server being down (if you're lucky). But unfortunately, sometimes this simply means that the dependencies are not contained in the repositories that Eclipse is trying to download them from, at least that is what i have encountered every now and then (not annoyingly often though).

So either the failure is temporary and you should try again or you are out of luck and may have to use a manual installation procedure (download and unpack in plugins folder).

Maybe you can increase your success rate by adding the repositories that supposedly contain the artifacts in the 'Available Software Sites' dialogue.

I'm not 100% sure of that though. In fact, I would like to find a 'perfect' answer to this question myself.

What usually works quite well is installing plugins via the Eclipse Marketplace.

Oh and sometimes this helps: Uncheck some options (like OSGI in your case).

Removing MySQL 5.7 Completely

You need to remove the /var/lib/mysql folder. Also, purge when you remove the packages (I'm told this helps).

sudo apt-get remove --purge mysql-server mysql-client mysql-common

sudo rm -rf /var/lib/mysql

I was encountering similar issues. The second line got rid of my issues and allowed me to set up MySql from scratch. Hopefully it helps you too!

curl: (60) SSL certificate problem: unable to get local issuer certificate

Yes you need to add a CA certificate also. Adding a code snippet in Node.js for clear view.

var fs = require(fs)
var path = require('path')
var https = require('https')
var port = process.env.PORT || 8080;
var app = express();

https.createServer({
key: fs.readFileSync(path.join(__dirname, './path to your private key/privkey.pem')),
cert: fs.readFileSync(path.join(__dirname, './path to your certificate/cert.pem')),
ca: fs.readFileSync(path.join(__dirname, './path to your CA file/chain.pem'))}, app).listen(port)

Not receiving Google OAuth refresh token

The refresh_token is only provided on the first authorization from the user. Subsequent authorizations, such as the kind you make while testing an OAuth2 integration, will not return the refresh_token again. :)

  1. Go to the page showing Apps with access to your account: https://myaccount.google.com/u/0/permissions.
  2. Under the Third-party apps menu, choose your app.
  3. Click Remove access and then click Ok to confirm
  4. The next OAuth2 request you make will return a refresh_token (providing that it also includes the 'access_type=offline' query parameter.

Alternatively, you can add the query parameters prompt=consent&access_type=offline to the OAuth redirect (see Google's OAuth 2.0 for Web Server Applications page).

This will prompt the user to authorize the application again and will always return a refresh_token.

I'm getting Key error in python

I fully agree with the Key error comments. You could also use the dictionary's get() method as well to avoid the exceptions. This could also be used to give a default path rather than None as shown below.

>>> d = {"a":1, "b":2}
>>> x = d.get("A",None)
>>> print x
None

document.getElementById replacement in angular4 / typescript?

Try this:

TypeScript file code:

(<HTMLInputElement>document.getElementById("name")).value

HTML code:

 <input id="name" type="text" #name /> 

Javascript Get Values from Multiple Select Option Box

Take a look at HTMLSelectElement.selectedOptions.

HTML

<select name="north-america" multiple>
  <option valud="ca" selected>Canada</a>
  <option value="mx" selected>Mexico</a>
  <option value="us">USA</a>
</select>

JavaScript

var elem = document.querySelector("select");

console.log(elem.selectedOptions);
//=> HTMLCollection [<option value="ca">Canada</option>, <option value="mx">Mexico</option>]

This would also work on non-multiple <select> elements


Warning: Support for this selectedOptions seems pretty unknown at this point

jquery - is not a function error

In my case, the same error had a much easier fix. Basically my function was in a .js file that was not included in the current aspx that was showing. All I needed was the include line.

Parsing a JSON string in Ruby

I suggest Oj as it is waaaaaay faster than the standard JSON library.

https://github.com/ohler55/oj

(see performance comparisons here)

How to use graphics.h in codeblocks?

  1. First download WinBGIm from http://winbgim.codecutter.org/ Extract it.
  2. Copy graphics.h and winbgim.h files in include folder of your compiler directory
  3. Copy libbgi.a to lib folder of your compiler directory
  4. In code::blocks open Settings >> Compiler and debugger >>linker settings click Add button in link libraries part and browse and select libbgi.a file
  5. In right part (i.e. other linker options) paste commands -lbgi -lgdi32 -lcomdlg32 -luuid -loleaut32 -lole32
  6. Click OK

For detail information follow this link.