Programs & Examples On #Axshockwaveflash

AxShockwaveFlash is a .net wrapper component for loading flash movies (swf) on a windows form.

When should I use the Visitor Design Pattern?

One way to look at it is that the visitor pattern is a way of letting your clients add additional methods to all of your classes in a particular class hierarchy.

It is useful when you have a fairly stable class hierarchy, but you have changing requirements of what needs to be done with that hierarchy.

The classic example is for compilers and the like. An Abstract Syntax Tree (AST) can accurately define the structure of the programming language, but the operations you might want to do on the AST will change as your project advances: code-generators, pretty-printers, debuggers, complexity metrics analysis.

Without the Visitor Pattern, every time a developer wanted to add a new feature, they would need to add that method to every feature in the base class. This is particularly hard when the base classes appear in a separate library, or are produced by a separate team.

(I have heard it argued that the Visitor pattern is in conflict with good OO practices, because it moves the operations of the data away from the data. The Visitor pattern is useful in precisely the situation that the normal OO practices fail.)

javascript windows alert with redirect function

Use this if you also want to consider non-javascript users:

echo ("<SCRIPT LANGUAGE='JavaScript'>
           window.alert('Succesfully Updated')
           window.location.href='http://someplace.com';
       </SCRIPT>
       <NOSCRIPT>
           <a href='http://someplace.com'>Successfully Updated. Click here if you are not redirected.</a>
       </NOSCRIPT>");

Link error "undefined reference to `__gxx_personality_v0'" and g++

It sounds like you're trying to link with your resulting object file with gcc instead of g++:

Note that programs using C++ object files must always be linked with g++, in order to supply the appropriate C++ libraries. Attempting to link a C++ object file with the C compiler gcc will cause "undefined reference" errors for C++ standard library functions:

$ g++ -Wall -c hello.cc
$ gcc hello.o       (should use g++)
hello.o: In function `main':
hello.o(.text+0x1b): undefined reference to `std::cout'
.....
hello.o(.eh_frame+0x11):
  undefined reference to `__gxx_personality_v0'

Source: An Introduction to GCC - for the GNU compilers gcc and g++

How to have an auto incrementing version number (Visual Studio)?

If you add an AssemblyInfo class to your project and amend the AssemblyVersion attribute to end with an asterisk, for example:

[assembly: AssemblyVersion("2.10.*")]

Visual studio will increment the final number for you according to these rules (thanks galets, I had that completely wrong!)

To reference this version in code, so you can display it to the user, you use reflection. For example,

Version version = System.Reflection.Assembly.GetExecutingAssembly().GetName().Version;
DateTime buildDate = new DateTime(2000, 1, 1)
                        .AddDays(version.Build).AddSeconds(version.Revision * 2);
string displayableVersion = $"{version} ({buildDate})";

Three important gotchas that you should know

From @ashes999:

It's also worth noting that if both AssemblyVersion and AssemblyFileVersion are specified, you won't see this on your .exe.

From @BrainSlugs83:

Setting only the 4th number to be * can be bad, as the version won't always increment. The 3rd number is the number of days since the year 2000, and the 4th number is the number of seconds since midnight (divided by 2) [IT IS NOT RANDOM]. So if you built the solution late in a day one day, and early in a day the next day, the later build would have an earlier version number. I recommend always using X.Y.* instead of X.Y.Z.* because your version number will ALWAYS increase this way.

Newer versions of Visual Studio give this error:

(this thread begun in 2009)

The specified version string contains wildcards, which are not compatible with determinism. Either remove wildcards from the version string, or disable determinism for this compilation.

See this SO answer which explains how to remove determinism (https://stackoverflow.com/a/58101474/1555612)

Inserting string at position x of another string

If ES2018's lookbehind is available, one more regexp solution, that makes use of it to "replace" at a zero-width position after the Nth character (similar to @Kamil Kielczewski's, but without storing the initial characters in a capturing group):

"I want apple".replace(/(?<=^.{6})/, " an")

_x000D_
_x000D_
var a = "I want apple";_x000D_
var b = " an";_x000D_
var position = 6;_x000D_
_x000D_
var r= a.replace(new RegExp(`(?<=^.{${position}})`), b);_x000D_
_x000D_
console.log(r);_x000D_
console.log("I want apple".replace(/(?<=^.{6})/, " an"));
_x000D_
_x000D_
_x000D_

default value for struct member in C

You can use some function to initialize struct as follows,

typedef struct
{
    int flag;
} MyStruct;

MyStruct GetMyStruct(int value)
{
    MyStruct My = {0};
    My.flag = value;
    return My;
}

void main (void)
{
    MyStruct temp;
    temp = GetMyStruct(3);
    printf("%d\n", temp.flag);
}

EDIT:

typedef struct
{
    int flag;
} MyStruct;

MyStruct MyData[20];

MyStruct GetMyStruct(int value)
{
    MyStruct My = {0};
    My.flag = value;
    return My;
}

void main (void)
{
    int i;
    for (i = 0; i < 20; i ++)
        MyData[i] = GetMyStruct(3);

    for (i = 0; i < 20; i ++)
        printf("%d\n", MyData[i].flag);
}

Multiple input in JOptionPane.showInputDialog

Yes. You know that you can put any Object into the Object parameter of most JOptionPane.showXXX methods, and often that Object happens to be a JPanel.

In your situation, perhaps you could use a JPanel that has several JTextFields in it:

import javax.swing.*;

public class JOptionPaneMultiInput {
   public static void main(String[] args) {
      JTextField xField = new JTextField(5);
      JTextField yField = new JTextField(5);

      JPanel myPanel = new JPanel();
      myPanel.add(new JLabel("x:"));
      myPanel.add(xField);
      myPanel.add(Box.createHorizontalStrut(15)); // a spacer
      myPanel.add(new JLabel("y:"));
      myPanel.add(yField);

      int result = JOptionPane.showConfirmDialog(null, myPanel, 
               "Please Enter X and Y Values", JOptionPane.OK_CANCEL_OPTION);
      if (result == JOptionPane.OK_OPTION) {
         System.out.println("x value: " + xField.getText());
         System.out.println("y value: " + yField.getText());
      }
   }
}

jQuery deferreds and promises - .then() vs .done()

Only use .then()

These are the disadvantages of .done()

  • can not be chained
  • block resolve() call (all .done() handlers will be executed synchronous)
  • resolve() might get an exception from registered .done() handlers(!)
  • an exception in a .done() half-kills the deferred:
    • further .done() handlers will be silently skipped

I thought temporarily that .then(oneArgOnly) always requires .catch() so that no exception gets silently ignored, but that is not true any more: the unhandledrejection event logs unhandled .then() exceptions on the console (as default). Very reasonable! No reason left to use .done() at all.

Proof

The following code snippet reveals, that:

  • all .done() handlers will be called synchronous at point of resolve()
    • logged as 1, 3, 5, 7
    • logged before the script falls through bottom
  • exception in a .done() influences resolve() caller
    • logged via catch around resolve()
  • exception breaks promise from further .done() resolution
    • 8 and 10 are not logged!
  • .then() has none of these problems
    • logged as 2, 4, 6, 9, 11 after thread turns idle
    • (snippet environment has no unhandledrejection is seems)

Btw, exceptions from .done() can’t be properly caught: because of the synchronous pattern of .done(), the error is either thrown at the point of .resolve() (might be library code!) or at the .done() call which attaches the culprit if the deferred is already resolved.

_x000D_
_x000D_
console.log('Start of script.');_x000D_
let deferred = $.Deferred();_x000D_
// deferred.resolve('Redemption.');_x000D_
deferred.fail(() => console.log('fail()'));_x000D_
deferred.catch(()=> console.log('catch()'));_x000D_
deferred.done(() => console.log('1-done()'));_x000D_
deferred.then(() => console.log('2-then()'));_x000D_
deferred.done(() => console.log('3-done()'));_x000D_
deferred.then(() =>{console.log('4-then()-throw');_x000D_
    throw 'thrown from 4-then()';});_x000D_
deferred.done(() => console.log('5-done()'));_x000D_
deferred.then(() => console.log('6-then()'));_x000D_
deferred.done(() =>{console.log('7-done()-throw');_x000D_
    throw 'thrown from 7-done()';});_x000D_
deferred.done(() => console.log('8-done()'));_x000D_
deferred.then(() => console.log('9-then()'));_x000D_
_x000D_
console.log('Resolving.');_x000D_
try {_x000D_
    deferred.resolve('Solution.');_x000D_
} catch(e) {_x000D_
    console.log(`Caught exception from handler_x000D_
        in resolve():`, e);_x000D_
}_x000D_
deferred.done(() => console.log('10-done()'));_x000D_
deferred.then(() => console.log('11-then()'));_x000D_
console.log('End of script.');
_x000D_
<script_x000D_
src="https://code.jquery.com/jquery-3.4.1.min.js"_x000D_
integrity="sha384-vk5WoKIaW/vJyUAd9n/wmopsmNhiy+L2Z+SBxGYnUkunIxVxAv/UtMOhba/xskxh"_x000D_
crossorigin="anonymous"_x000D_
></script>
_x000D_
_x000D_
_x000D_

Xcode 9 Swift Language Version (SWIFT_VERSION)

This Solution works when nothing else works:

I spent more than a week to convert the whole project and came to a solution below:

First, de-integrate the cocopods dependency from the project and then start converting the project to the latest swift version.

Go to Project Directory in the Terminal and Type:

pod deintegrate

This will de-integrate cocopods from the project and No traces of CocoaPods will be left in the project. But at the same time, it won't delete the xcworkspace and podfiles. It's ok if they are present.

Now you have to open xcodeproj(not xcworkspace) and you will get lots of errors because you have called cocoapods dependency methods in your main projects.

So to remove those errors you have two options:

  1. Comment down all the code you have used from cocoapods library.
  2. Create a wrapper class which has dummy methods similar to cocopods library, and then call it.

Once all the errors get removed you can convert the code to the latest swift version.

Sometimes if you are getting weird errors then try cleaning derived data and try again.

Benefits of inline functions in C++?

It is not all about performance. Both C++ and C are used for embedded programming, sitting on top of hardware. If you would, for example, write an interrupt handler, you need to make sure that the code can be executed at once, without additional registers and/or memory pages being being swapped. That is when inline comes in handy. Good compilers do some "inlining" themselves when speed is needed, but "inline" compels them.

Converting file size in bytes to human-readable string

Here's mine - works for really big files too -_-

function formatFileSize(size)
{
    var sizes = [' Bytes', ' KB', ' MB', ' GB', ' TB', ' PB', ' EB', ' ZB', ' YB'];
    for (var i = 1; i < sizes.length; i++)
    {
        if (size < Math.pow(1024, i)) return (Math.round((size/Math.pow(1024, i-1))*100)/100) + sizes[i-1];
    }
    return size;
}

How to convert LINQ query result to List?

No need to do so much works..

var query = from c in obj.tbCourses
        where ...
        select c;

Then you can use:

List<course> list_course= query.ToList<course>();

It works fine for me.

Can you change what a symlink points to after it is created?

Yes, you can!

$ ln -sfn source_file_or_directory_name softlink_name

Custom alert and confirm box in jquery

jQuery UI has it's own elements, but jQuery alone hasn't.

http://jqueryui.com/dialog/

Working example:

<!doctype html>

<html lang="en">
<head>
  <meta charset="utf-8" />
  <title>jQuery UI Dialog - Default functionality</title>
  <link rel="stylesheet" href="http://code.jquery.com/ui/1.10.3/themes/smoothness/jquery-ui.css" />
  <script src="http://code.jquery.com/jquery-1.9.1.js"></script>
  <script src="http://code.jquery.com/ui/1.10.3/jquery-ui.js"></script>
  <link rel="stylesheet" href="/resources/demos/style.css" />
  <script>
  $(function() {
    $( "#dialog" ).dialog();
  });
  </script>
</head>
<body>

<div id="dialog" title="Basic dialog">
  <p>This is the default dialog which is useful for displaying information. The dialog window can be moved, resized and closed with the 'x' icon.</p>
</div>


</body>
</html>

SQL Server equivalent to MySQL enum data type?

CREATE FUNCTION ActionState_Preassigned()
RETURNS tinyint
AS
BEGIN
    RETURN 0
END

GO

CREATE FUNCTION ActionState_Unassigned()
RETURNS tinyint
AS
BEGIN
    RETURN 1
END

-- etc...

Where performance matters, still use the hard values.

Regular Expressions: Search in list

You can create an iterator in Python 3.x or a list in Python 2.x by using:

filter(r.match, list)

To convert the Python 3.x iterator to a list, simply cast it; list(filter(..)).

In mocha testing while calling asynchronous function how to avoid the timeout Error: timeout of 2000ms exceeded

I find that the "solution" of just increasing the timeouts obscures what's really going on here, which is either

  1. Your code and/or network calls are way too slow (should be sub 100 ms for a good user experience)
  2. The assertions (tests) are failing and something is swallowing the errors before Mocha is able to act on them.

You usually encounter #2 when Mocha doesn't receive assertion errors from a callback. This is caused by some other code swallowing the exception further up the stack. The right way of dealing with this is to fix the code and not swallow the error.

When external code swallows your errors

In case it's a library function that you are unable to modify, you need to catch the assertion error and pass it onto Mocha yourself. You do this by wrapping your assertion callback in a try/catch block and pass any exceptions to the done handler.

it('should not fail', function (done) { // Pass reference here!

  i_swallow_errors(function (err, result) {
    try { // boilerplate to be able to get the assert failures
      assert.ok(true);
      assert.equal(result, 'bar');
      done();
    } catch (error) {
      done(error);
    }
  });
});

This boilerplate can of course be extracted into some utility function to make the test a little more pleasing to the eye:

it('should not fail', function (done) { // Pass reference here!
    i_swallow_errors(handleError(done, function (err, result) {
        assert.equal(result, 'bar');
    }));
});

// reusable boilerplate to be able to get the assert failures
function handleError(done, fn) {
    try { 
        fn();
        done();
    } catch (error) {
        done(error);
    }
}

Speeding up network tests

Other than that I suggest you pick up the advice on starting to use test stubs for network calls to make tests pass without having to rely on a functioning network. Using Mocha, Chai and Sinon the tests might look something like this

describe('api tests normally involving network calls', function() {

    beforeEach: function () {
        this.xhr = sinon.useFakeXMLHttpRequest();
        var requests = this.requests = [];

        this.xhr.onCreate = function (xhr) {
            requests.push(xhr);
        };
    },

    afterEach: function () {
        this.xhr.restore();
    }


    it("should fetch comments from server", function () {
        var callback = sinon.spy();
        myLib.getCommentsFor("/some/article", callback);
        assertEquals(1, this.requests.length);

        this.requests[0].respond(200, { "Content-Type": "application/json" },
                                 '[{ "id": 12, "comment": "Hey there" }]');
        expect(callback.calledWith([{ id: 12, comment: "Hey there" }])).to.be.true;
    });

});

See Sinon's nise docs for more info.

Bootstrap carousel multiple frames at once

_x000D_
_x000D_
    $('#carousel-example-generic').on('slid.bs.carousel', function () {_x000D_
        $(".item.active:nth-child(" + ($(".carousel-inner .item").length -1) + ") + .item").insertBefore($(".item:first-child"));_x000D_
        $(".item.active:last-child").insertBefore($(".item:first-child"));_x000D_
    });    
_x000D_
        .item.active,_x000D_
        .item.active + .item,_x000D_
        .item.active + .item  + .item {_x000D_
           width: 33.3%;_x000D_
           display: block;_x000D_
           float:left;_x000D_
        }          
_x000D_
   <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" integrity="sha384-1q8mTJOASx8j1Au+a5WDVnPi2lkFfwwEAa8hDDdjZlpLegxhjVME1fgjWPGmkzs7" crossorigin="anonymous">_x000D_
_x000D_
<div id="carousel-example-generic" class="carousel slide" data-ride="carousel" style="max-width:800px;">_x000D_
  <!-- Indicators -->_x000D_
  <ol class="carousel-indicators">_x000D_
    <li data-target="#carousel-example-generic" data-slide-to="0" class="active"></li>_x000D_
    <li data-target="#carousel-example-generic" data-slide-to="1"></li>_x000D_
    <li data-target="#carousel-example-generic" data-slide-to="2"></li>_x000D_
  </ol>_x000D_
_x000D_
  <!-- Wrapper for slides -->_x000D_
  <div class="carousel-inner" role="listbox">_x000D_
    <div class="item active">_x000D_
        <img data-src="holder.js/300x200?text=1">_x000D_
    </div>_x000D_
    <div class="item">_x000D_
        <img data-src="holder.js/300x200?text=2">_x000D_
    </div>_x000D_
    <div class="item">_x000D_
        <img data-src="holder.js/300x200?text=3">_x000D_
    </div>_x000D_
    <div class="item">_x000D_
        <img data-src="holder.js/300x200?text=4">_x000D_
    </div>_x000D_
    <div class="item">_x000D_
        <img data-src="holder.js/300x200?text=5">_x000D_
    </div>_x000D_
    <div class="item">_x000D_
        <img data-src="holder.js/300x200?text=6">_x000D_
    </div>_x000D_
    <div class="item">_x000D_
        <img data-src="holder.js/300x200?text=7">_x000D_
    </div>    _x000D_
  </div>_x000D_
_x000D_
  <!-- Controls -->_x000D_
  <a class="left carousel-control" href="#carousel-example-generic" role="button" data-slide="prev">_x000D_
    <span class="glyphicon glyphicon-chevron-left" aria-hidden="true"></span>_x000D_
    <span class="sr-only">Previous</span>_x000D_
  </a>_x000D_
  <a class="right carousel-control" href="#carousel-example-generic" role="button" data-slide="next">_x000D_
    <span class="glyphicon glyphicon-chevron-right" aria-hidden="true"></span>_x000D_
    <span class="sr-only">Next</span>_x000D_
  </a>_x000D_
</div>_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>_x000D_
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js" integrity="sha384-0mSbJDEHialfmuBBQP6A4Qrprq5OVfW37PRR3j5ELqxss1yVqOtnepnHVP9aJ7xS" crossorigin="anonymous"></script>_x000D_
    <script src="https://cdnjs.cloudflare.com/ajax/libs/holder/2.9.1/holder.min.js"></script>_x000D_
    
_x000D_
_x000D_
_x000D_

Saving awk output to variable

variable=$(ps -ef | awk '/[p]ort 10/ {print $12}')

The [p] is a neat trick to remove the search from showing from ps

@Jeremy If you post the output of ps -ef | grep "port 10", and what you need from the line, it would be more easy to help you getting correct syntax

How do I prevent a form from being resized by the user?

If you want to prevent resize by dragging sizegrips and by the maximize button and by maximize by doubleclick on the header text, than insert the following code in the load event of the form:

    Me.FormBorderStyle = Windows.Forms.FormBorderStyle.FixedSingle ' Prevent size grips
    Me.MaximumSize = Me.Size ' Prevent maximize (also by doubleclick of header text)

Of course all choices of a formborderstyle beginning with Fixed will do.

How to return a value from a Form in C#?

delegates are the best option for sending data from one form to another.

public partial class frmImportContact : Form
{
     public delegate void callback_data(string someData);
    public event callback_data getData_CallBack;

    private void button_Click(object sender, EventArgs e)
    {
      string myData = "Top Secret Data To Share";
      getData_CallBack(myData);
    }

}

public partial class frmHireQuote : Form
{
     private void Button_Click(object sender, EventArgs e)
    {

      frmImportContact obj = new frmImportContact();
      obj.getData_CallBack += getData;
    }

    private void getData(string someData)
    {
         MessageBox.Show("someData");
    }
}

Select rows of a matrix that meet a condition

If your matrix is called m, just use :

R> m[m$three == 11, ]

GZIPInputStream reading line by line

here is with one line

try (BufferedReader br = new BufferedReader(
        new InputStreamReader(
           new GZIPInputStream(
              new FileInputStream(
                 "F:/gawiki-20090614-stub-meta-history.xml.gz"))))) 
     {br.readLine();}

Bold & Non-Bold Text In A Single UILabel?

Update

In Swift we don't have to deal with iOS5 old stuff besides syntax is shorter so everything becomes really simple:

Swift 5

func attributedString(from string: String, nonBoldRange: NSRange?) -> NSAttributedString {
    let fontSize = UIFont.systemFontSize
    let attrs = [
        NSAttributedString.Key.font: UIFont.boldSystemFont(ofSize: fontSize),
        NSAttributedString.Key.foregroundColor: UIColor.black
    ]
    let nonBoldAttribute = [
        NSAttributedString.Key.font: UIFont.systemFont(ofSize: fontSize),
    ]
    let attrStr = NSMutableAttributedString(string: string, attributes: attrs)
    if let range = nonBoldRange {
        attrStr.setAttributes(nonBoldAttribute, range: range)
    }
    return attrStr
}

Swift 3

func attributedString(from string: String, nonBoldRange: NSRange?) -> NSAttributedString {
    let fontSize = UIFont.systemFontSize
    let attrs = [
        NSFontAttributeName: UIFont.boldSystemFont(ofSize: fontSize),
        NSForegroundColorAttributeName: UIColor.black
    ]
    let nonBoldAttribute = [
        NSFontAttributeName: UIFont.systemFont(ofSize: fontSize),
    ]
    let attrStr = NSMutableAttributedString(string: string, attributes: attrs)
    if let range = nonBoldRange {
        attrStr.setAttributes(nonBoldAttribute, range: range)
    }
    return attrStr
}

Usage:

let targetString = "Updated 2012/10/14 21:59 PM"
let range = NSMakeRange(7, 12)

let label = UILabel(frame: CGRect(x:0, y:0, width:350, height:44))
label.backgroundColor = UIColor.white
label.attributedText = attributedString(from: targetString, nonBoldRange: range)
label.sizeToFit()

Bonus: Internationalisation

Some people commented about internationalisation. I personally think this is out of scope of this question but for instructional purposes this is how I would do it

// Date we want to show
let date = Date()

// Create the string.
// I don't set the locale because the default locale of the formatter is `NSLocale.current` so it's good for internationalisation :p
let formatter = DateFormatter()
formatter.dateStyle = .medium
formatter.timeStyle = .short
let targetString = String(format: NSLocalizedString("Update %@", comment: "Updated string format"),
                          formatter.string(from: date))

// Find the range of the non-bold part
formatter.timeStyle = .none
let nonBoldRange = targetString.range(of: formatter.string(from: date))

// Convert Range<Int> into NSRange
let nonBoldNSRange: NSRange? = nonBoldRange == nil ?
    nil :
    NSMakeRange(targetString.distance(from: targetString.startIndex, to: nonBoldRange!.lowerBound),
                targetString.distance(from: nonBoldRange!.lowerBound, to: nonBoldRange!.upperBound))

// Now just build the attributed string as before :)
label.attributedText = attributedString(from: targetString,
                                        nonBoldRange: nonBoldNSRange)

Result (Assuming English and Japanese Localizable.strings are available)

enter image description here

enter image description here


Previous answer for iOS6 and later (Objective-C still works):

In iOS6 UILabel, UIButton, UITextView, UITextField, support attributed strings which means we don't need to create CATextLayers as our recipient for attributed strings. Furthermore to make the attributed string we don't need to play with CoreText anymore :) We have new classes in obj-c Foundation.framework like NSParagraphStyle and other constants that will make our life easier. Yay!

So, if we have this string:

NSString *text = @"Updated: 2012/10/14 21:59"

We only need to create the attributed string:

if ([_label respondsToSelector:@selector(setAttributedText:)])
{
    // iOS6 and above : Use NSAttributedStrings

    // Create the attributes
    const CGFloat fontSize = 13;
    NSDictionary *attrs = @{
        NSFontAttributeName:[UIFont boldSystemFontOfSize:fontSize],
        NSForegroundColorAttributeName:[UIColor whiteColor]
    };
    NSDictionary *subAttrs = @{
        NSFontAttributeName:[UIFont systemFontOfSize:fontSize]
    };

    // Range of " 2012/10/14 " is (8,12). Ideally it shouldn't be hardcoded
    // This example is about attributed strings in one label
    // not about internationalisation, so we keep it simple :)
    // For internationalisation example see above code in swift
    const NSRange range = NSMakeRange(8,12);

    // Create the attributed string (text + attributes)
    NSMutableAttributedString *attributedText =
      [[NSMutableAttributedString alloc] initWithString:text
                                             attributes:attrs];
    [attributedText setAttributes:subAttrs range:range];

    // Set it in our UILabel and we are done!
    [_label setAttributedText:attributedText];
} else {
    // iOS5 and below
    // Here we have some options too. The first one is to do something
    // less fancy and show it just as plain text without attributes.
    // The second is to use CoreText and get similar results with a bit
    // more of code. Interested people please look down the old answer.

    // Now I am just being lazy so :p
    [_label setText:text];
}

There is a couple of good introductory blog posts here from guys at invasivecode that explain with more examples uses of NSAttributedString, look for "Introduction to NSAttributedString for iOS 6" and "Attributed strings for iOS using Interface Builder" :)

PS: Above code it should work but it was brain-compiled. I hope it is enough :)


Old Answer for iOS5 and below

Use a CATextLayer with an NSAttributedString ! much lighter and simpler than 2 UILabels. (iOS 3.2 and above)

Example.

Don't forget to add QuartzCore framework (needed for CALayers), and CoreText (needed for the attributed string.)

#import <QuartzCore/QuartzCore.h>
#import <CoreText/CoreText.h>

Below example will add a sublayer to the toolbar of the navigation controller. à la Mail.app in the iPhone. :)

- (void)setRefreshDate:(NSDate *)aDate
{
    [aDate retain];
    [refreshDate release];
    refreshDate = aDate;

    if (refreshDate) {

        /* Create the text for the text layer*/    
        NSDateFormatter *df = [[NSDateFormatter alloc] init];
        [df setDateFormat:@"MM/dd/yyyy hh:mm"];

        NSString *dateString = [df stringFromDate:refreshDate];
        NSString *prefix = NSLocalizedString(@"Updated", nil);
        NSString *text = [NSString stringWithFormat:@"%@: %@",prefix, dateString];
        [df release];

        /* Create the text layer on demand */
        if (!_textLayer) {
            _textLayer = [[CATextLayer alloc] init];
            //_textLayer.font = [UIFont boldSystemFontOfSize:13].fontName; // not needed since `string` property will be an NSAttributedString
            _textLayer.backgroundColor = [UIColor clearColor].CGColor;
            _textLayer.wrapped = NO;
            CALayer *layer = self.navigationController.toolbar.layer; //self is a view controller contained by a navigation controller
            _textLayer.frame = CGRectMake((layer.bounds.size.width-180)/2 + 10, (layer.bounds.size.height-30)/2 + 10, 180, 30);
            _textLayer.contentsScale = [[UIScreen mainScreen] scale]; // looks nice in retina displays too :)
            _textLayer.alignmentMode = kCAAlignmentCenter;
            [layer addSublayer:_textLayer];
        }

        /* Create the attributes (for the attributed string) */
        CGFloat fontSize = 13;
        UIFont *boldFont = [UIFont boldSystemFontOfSize:fontSize];
        CTFontRef ctBoldFont = CTFontCreateWithName((CFStringRef)boldFont.fontName, boldFont.pointSize, NULL);
        UIFont *font = [UIFont systemFontOfSize:13];
        CTFontRef ctFont = CTFontCreateWithName((CFStringRef)font.fontName, font.pointSize, NULL);
        CGColorRef cgColor = [UIColor whiteColor].CGColor;
        NSDictionary *attributes = [NSDictionary dictionaryWithObjectsAndKeys:
                                    (id)ctBoldFont, (id)kCTFontAttributeName,
                                    cgColor, (id)kCTForegroundColorAttributeName, nil];
        CFRelease(ctBoldFont);
        NSDictionary *subAttributes = [NSDictionary dictionaryWithObjectsAndKeys:(id)ctFont, (id)kCTFontAttributeName, nil];
        CFRelease(ctFont);

        /* Create the attributed string (text + attributes) */
        NSMutableAttributedString *attrStr = [[NSMutableAttributedString alloc] initWithString:text attributes:attributes];
        [attrStr addAttributes:subAttributes range:NSMakeRange(prefix.length, 12)]; //12 is the length of " MM/dd/yyyy/ "

        /* Set the attributes string in the text layer :) */
        _textLayer.string = attrStr;
        [attrStr release];

        _textLayer.opacity = 1.0;
    } else {
        _textLayer.opacity = 0.0;
        _textLayer.string = nil;
    }
}

In this example I only have two different types of font (bold and normal) but you could also have different font size, different color, italics, underlined, etc. Take a look at NSAttributedString / NSMutableAttributedString and CoreText attributes string keys.

Hope it helps

How to get the path of the batch script in Windows?

%~dp0 will be the directory. Here's some documentation on all of the path modifiers. Fun stuff :-)

To remove the final backslash, you can use the :n,m substring syntax, like so:

SET mypath=%~dp0
echo %mypath:~0,-1%

I don't believe there's a way to combine the %0 syntax with the :~n,m syntax, unfortunately.

SQL Server 2008: TOP 10 and distinct together

SELECT TOP 14 A, B, C
  FROM MyDatabase
  Where EXISTS 
   (
     Select Distinct[A] FROM MyDatabase
    )

Does C# support multiple inheritance?

Multiple inheritance allows programmers to create classes that combine aspects of multiple classes and their corresponding hierarchies. For ex. the C++ allows you to inherit from more than one class

In C#, the classes are only allowed to inherit from a single parent class, which is called single inheritance. But you can use interfaces or a combination of one class and interface(s), where interface(s) should be followed by class name in the signature.

Ex:

Class FirstClass { }
Class SecondClass { }

interface X { }
interface Y { }

You can inherit like the following:

class NewClass : X, Y { } In the above code, the class "NewClass" is created from multiple interfaces.

class NewClass : FirstClass, X { } In the above code, the class "NewClass" is created from interface X and class "FirstClass".

Is it possible to use an input value attribute as a CSS selector?

You can use Css3 attribute selector or attribute value selector.

/This will make all input whose value is defined to red/

input[value]{
color:red;
}

/This will make conditional selection depending on input value/

input[value="United States"]{
color:red;
} 

There are other attribute selector like attribute contains value selector,

input[value="United S"]{
color: red;
}

This will still make any input with United state as red text.

Than we attribute value starts with selector

input[value^='united']{
color: red;
}

Any input text starts with 'united' will have font color red

And the last one is attribute value ends with selector

input[value$='States']{
color:red;
}

Any input value ends with 'States' will have font color red

CSS Div width percentage and padding without breaking layout

If you want the #header to be the same width as your container, with 10px of padding, you can leave out its width declaration. That will cause it to implicitly take up its entire parent's width (since a div is by default a block level element).

Then, since you haven't defined a width on it, the 10px of padding will be properly applied inside the element, rather than adding to its width:

#container {
    position: relative;
    width: 80%;
}

#header {
    position: relative;
    height: 50px;
    padding: 10px;
}

You can see it in action here.

The key when using percentage widths and pixel padding/margins is not to define them on the same element (if you want to accurately control the size). Apply the percentage width to the parent and then the pixel padding/margin to a display: block child with no width set.


Update

Another option for dealing with this is to use the box-sizing CSS rule:

#container { 
    -webkit-box-sizing: border-box; /* Safari/Chrome, other WebKit */
    -moz-box-sizing: border-box;    /* Firefox, other Gecko */
    box-sizing: border-box;         /* Opera/IE 8+ */

    /* Since this element now uses border-box sizing, the 10px of horizontal
       padding will be drawn inside the 80% width */
    width: 80%;
    padding: 0 10px;
}

Here's a post talking about how box-sizing works.

IntelliJ IDEA generating serialVersionUID

I am using Android Studio 2.1 and I have better consistency of getting the lightbulb by clicking on the class Name and hover over it for a second.

Mailto links do nothing in Chrome but work in Firefox?

The usual <a href="mailto:[email protected]"></a> should work, but remember you must have a default email program set on your computer. For ex, I'm using Ubuntu 14.04 and the default email is thunderbird, which works fine.

Javascript find json value

Just use the ES6 find() function in a functional way:

_x000D_
_x000D_
var data=[{name:"Afghanistan",code:"AF"},{name:"Åland Islands",code:"AX"},{name:"Albania",code:"AL"},{name:"Algeria",code:"DZ"}];

let country = data.find(el => el.code === "AL");
// => {name: "Albania", code: "AL"}
console.log(country["name"]);
_x000D_
_x000D_
_x000D_

or Lodash _.find:

_x000D_
_x000D_
var data=[{name:"Afghanistan",code:"AF"},{name:"Åland Islands",code:"AX"},{name:"Albania",code:"AL"},{name:"Algeria",code:"DZ"}];

let country = _.find(data, ["code", "AL"]);
// => {name: "Albania", code: "AL"}
console.log(country["name"]);
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>
_x000D_
_x000D_
_x000D_

Android camera intent

try this code

Intent photo= new Intent("android.media.action.IMAGE_CAPTURE");
                    startActivityForResult(photo, CAMERA_PIC_REQUEST);

Resetting Select2 value in dropdown with reset button

version 4.0

$('#d').val('').trigger('change');

This is the correct solution from now on according to deprecated message thrown in debug mode: "The select2("val") method has been deprecated and will be removed in later Select2 versions. Use $element.val() instead"

How can I override the OnBeforeUnload dialog and replace it with my own?

You can't modify the default dialogue for onbeforeunload, so your best bet may be to work with it.

window.onbeforeunload = function() {
    return 'You have unsaved changes!';
}

Here's a reference to this from Microsoft:

When a string is assigned to the returnValue property of window.event, a dialog box appears that gives users the option to stay on the current page and retain the string that was assigned to it. The default statement that appears in the dialog box, "Are you sure you want to navigate away from this page? ... Press OK to continue, or Cancel to stay on the current page.", cannot be removed or altered.

The problem seems to be:

  1. When onbeforeunload is called, it will take the return value of the handler as window.event.returnValue.
  2. It will then parse the return value as a string (unless it is null).
  3. Since false is parsed as a string, the dialogue box will fire, which will then pass an appropriate true/false.

The result is, there doesn't seem to be a way of assigning false to onbeforeunload to prevent it from the default dialogue.

Additional notes on jQuery:

  • Setting the event in jQuery may be problematic, as that allows other onbeforeunload events to occur as well. If you wish only for your unload event to occur I'd stick to plain ol' JavaScript for it.
  • jQuery doesn't have a shortcut for onbeforeunload so you'd have to use the generic bind syntax.

    $(window).bind('beforeunload', function() {} );
    

Edit 09/04/2018: custom messages in onbeforeunload dialogs are deprecated since chrome-51 (cf: release note)

Why use #ifndef CLASS_H and #define CLASS_H in .h file but not in .cpp?

That's done for header files so that the contents only appear once in each preprocessed source file, even if it's included more than once (usually because it's included from other header files). The first time it's included, the symbol CLASS_H (known as an include guard) hasn't been defined yet, so all the contents of the file are included. Doing this defines the symbol, so if it's included again, the contents of the file (inside the #ifndef/#endif block) are skipped.

There's no need to do this for the source file itself since (normally) that's not included by any other files.

For your last question, class.h should contain the definition of the class, and declarations of all its members, associated functions, and whatever else, so that any file that includes it has enough information to use the class. The implementations of the functions can go in a separate source file; you only need the declarations to call them.

ASP.NET MVC3 - textarea with @Html.EditorFor

Declare in your Model with

  [DataType(DataType.MultilineText)]
  public string urString { get; set; }

Then in .cshtml can make use of editor as below. you can make use of @cols and @rows for TextArea size

     @Html.EditorFor(model => model.urString, new { htmlAttributes = new { @class = "",@cols = 35, @rows = 3 } })

Thanks !

Get size of an Iterable in Java

Instead of using loops and counting each element or using and third party library we can simply typecast the iterable in ArrayList and get its size.

((ArrayList) iterable).size();

How to disable scrolling the document body?

I know this is an ancient question, but I just thought that I'd weigh in.

I'm using disableScroll. Simple and it works like in a dream.

I have had some trouble disabling scroll on body, but allowing it on child elements (like a modal or a sidebar). It looks like that something can be done using disableScroll.on([element], [options]);, but I haven't gotten that to work just yet.


The reason that this is prefered compared to overflow: hidden; on body is that the overflow-hidden can get nasty, since some things might add overflow: hidden; like this:

... This is good for preloaders and such, since that is rendered before the CSS is finished loading.

But it gives problems, when an open navigation should add a class to the body-tag (like <body class="body__nav-open">). And then it turns into one big tug-of-war with overflow: hidden; !important and all kinds of crap.

ASP.NET MVC Conditional validation

There is now a framework that does this conditional validation (among other handy data annotation validations) out of the box: http://foolproof.codeplex.com/

Specifically, take a look at the [RequiredIfTrue("IsSenior")] validator. You put that directly on the property you want to validate, so you get the desired behavior of the validation error being associated to the "Senior" property.

It is available as a NuGet package.

How do I test if a variable does not equal either of two values?

ECMA2016 Shortest answer, specially good when checking againt multiple values:

if (!["A","B", ...].includes(test)) {}

How to ping ubuntu guest on VirtualBox

Using NAT (the default) this is not possible. Bridged Networking should allow it. If bridged does not work for you (this may be the case when your network adminstration does not allow multiple IP addresses on one physical interface), you could try 'Host-only networking' instead.

For configuration of Host-only here is a quote from the vbox manual(which is pretty good). http://www.virtualbox.org/manual/ch06.html:

For host-only networking, like with internal networking, you may find the DHCP server useful that is built into VirtualBox. This can be enabled to then manage the IP addresses in the host-only network since otherwise you would need to configure all IP addresses statically.

In the VirtualBox graphical user interface, you can configure all these items in the global settings via "File" -> "Settings" -> "Network", which lists all host-only networks which are presently in use. Click on the network name and then on the "Edit" button to the right, and you can modify the adapter and DHCP settings.

ImportError: No module named Crypto.Cipher

On the mac... if you run into this.. try to see if you can import crypto instead?

If so.. the package name is the issue C vs c. To get around this.. just add these lines to the top of your script.

import crypto
import sys
sys.modules['Crypto'] = crypto

You know should be able to import paramiko successfully.

Detect network connection type on Android

To get a more precise (and user friendly) information about connection type. You can use this code (derived from a @hide method in TelephonyManager.java).

This method returns a String describing the current connection type.
i.e. one of : "WIFI" , "2G" , "3G" , "4G" , "5G" , "-" (not connected) or "?" (unknown)

Remark: This code requires API 25+, but you can easily support older versions by using int instead of const. (See comments in code).

public static String getNetworkClass(Context context) {
    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);      
    NetworkInfo info = cm.getActiveNetworkInfo();
    if (info == null || !info.isConnected())
        return "-"; // not connected
    if (info.getType() == ConnectivityManager.TYPE_WIFI)
        return "WIFI";
    if (info.getType() == ConnectivityManager.TYPE_MOBILE) {
        int networkType = info.getSubtype();
        switch (networkType) {
            case TelephonyManager.NETWORK_TYPE_GPRS:
            case TelephonyManager.NETWORK_TYPE_EDGE:
            case TelephonyManager.NETWORK_TYPE_CDMA:
            case TelephonyManager.NETWORK_TYPE_1xRTT:
            case TelephonyManager.NETWORK_TYPE_IDEN:     // api< 8: replace by 11
            case TelephonyManager.NETWORK_TYPE_GSM:      // api<25: replace by 16
                return "2G";
            case TelephonyManager.NETWORK_TYPE_UMTS:
            case TelephonyManager.NETWORK_TYPE_EVDO_0:
            case TelephonyManager.NETWORK_TYPE_EVDO_A:
            case TelephonyManager.NETWORK_TYPE_HSDPA:
            case TelephonyManager.NETWORK_TYPE_HSUPA:
            case TelephonyManager.NETWORK_TYPE_HSPA:
            case TelephonyManager.NETWORK_TYPE_EVDO_B:   // api< 9: replace by 12
            case TelephonyManager.NETWORK_TYPE_EHRPD:    // api<11: replace by 14
            case TelephonyManager.NETWORK_TYPE_HSPAP:    // api<13: replace by 15
            case TelephonyManager.NETWORK_TYPE_TD_SCDMA: // api<25: replace by 17
                return "3G";
            case TelephonyManager.NETWORK_TYPE_LTE:      // api<11: replace by 13
            case TelephonyManager.NETWORK_TYPE_IWLAN:    // api<25: replace by 18
            case 19: // LTE_CA
                return "4G";
            case TelephonyManager.NETWORK_TYPE_NR:       // api<29: replace by 20
                return "5G";
            default:
                return "?";
         }
    }
    return "?";
}

How to crop a CvMat in OpenCV?

To create a copy of the crop we want, we can do the following,

// Read img
cv::Mat img = cv::imread("imgFileName");
cv::Mat croppedImg;

// This line picks out the rectangle from the image
// and copies to a new Mat
img(cv::Rect(xMin,yMin,xMax-xMin,yMax-yMin)).copyTo(croppedImg);

// Display diff
cv::imshow( "Original Image",  img );
cv::imshow( "Cropped Image",  croppedImg);
cv::waitKey();

Bootstrap modal: is not a function

I added a modal dialog in jsp and tried to open it with javascript in jsx and hit the same error: "...modal is not a function"

In my case, simply by adding the missing import to the jsx solved the problem.

`import "./../bower/bootstrap/js/modal.js"; // or import ".../bootstrap.min.js"` 

SQL query return data from multiple tables

Part 1 - Joins and Unions

This answer covers:

  1. Part 1
    • Joining two or more tables using an inner join (See the wikipedia entry for additional info)
    • How to use a union query
    • Left and Right Outer Joins (this stackOverflow answer is excellent to describe types of joins)
    • Intersect queries (and how to reproduce them if your database doesn't support them) - this is a function of SQL-Server (see info) and part of the reason I wrote this whole thing in the first place.
  2. Part 2
    • Subqueries - what they are, where they can be used and what to watch out for
    • Cartesian joins AKA - Oh, the misery!

There are a number of ways to retrieve data from multiple tables in a database. In this answer, I will be using ANSI-92 join syntax. This may be different to a number of other tutorials out there which use the older ANSI-89 syntax (and if you are used to 89, may seem much less intuitive - but all I can say is to try it) as it is much easier to understand when the queries start getting more complex. Why use it? Is there a performance gain? The short answer is no, but it is easier to read once you get used to it. It is easier to read queries written by other folks using this syntax.

I am also going to use the concept of a small caryard which has a database to keep track of what cars it has available. The owner has hired you as his IT Computer guy and expects you to be able to drop him the data that he asks for at the drop of a hat.

I have made a number of lookup tables that will be used by the final table. This will give us a reasonable model to work from. To start off, I will be running my queries against an example database that has the following structure. I will try to think of common mistakes that are made when starting out and explain what goes wrong with them - as well as of course showing how to correct them.

The first table is simply a color listing so that we know what colors we have in the car yard.

mysql> create table colors(id int(3) not null auto_increment primary key, 
    -> color varchar(15), paint varchar(10));
Query OK, 0 rows affected (0.01 sec)

mysql> show columns from colors;
+-------+-------------+------+-----+---------+----------------+
| Field | Type        | Null | Key | Default | Extra          |
+-------+-------------+------+-----+---------+----------------+
| id    | int(3)      | NO   | PRI | NULL    | auto_increment |
| color | varchar(15) | YES  |     | NULL    |                |
| paint | varchar(10) | YES  |     | NULL    |                |
+-------+-------------+------+-----+---------+----------------+
3 rows in set (0.01 sec)

mysql> insert into colors (color, paint) values ('Red', 'Metallic'), 
    -> ('Green', 'Gloss'), ('Blue', 'Metallic'), 
    -> ('White' 'Gloss'), ('Black' 'Gloss');
Query OK, 5 rows affected (0.00 sec)
Records: 5  Duplicates: 0  Warnings: 0

mysql> select * from colors;
+----+-------+----------+
| id | color | paint    |
+----+-------+----------+
|  1 | Red   | Metallic |
|  2 | Green | Gloss    |
|  3 | Blue  | Metallic |
|  4 | White | Gloss    |
|  5 | Black | Gloss    |
+----+-------+----------+
5 rows in set (0.00 sec)

The brands table identifies the different brands of the cars out caryard could possibly sell.

mysql> create table brands (id int(3) not null auto_increment primary key, 
    -> brand varchar(15));
Query OK, 0 rows affected (0.01 sec)

mysql> show columns from brands;
+-------+-------------+------+-----+---------+----------------+
| Field | Type        | Null | Key | Default | Extra          |
+-------+-------------+------+-----+---------+----------------+
| id    | int(3)      | NO   | PRI | NULL    | auto_increment |
| brand | varchar(15) | YES  |     | NULL    |                |
+-------+-------------+------+-----+---------+----------------+
2 rows in set (0.01 sec)

mysql> insert into brands (brand) values ('Ford'), ('Toyota'), 
    -> ('Nissan'), ('Smart'), ('BMW');
Query OK, 5 rows affected (0.00 sec)
Records: 5  Duplicates: 0  Warnings: 0

mysql> select * from brands;
+----+--------+
| id | brand  |
+----+--------+
|  1 | Ford   |
|  2 | Toyota |
|  3 | Nissan |
|  4 | Smart  |
|  5 | BMW    |
+----+--------+
5 rows in set (0.00 sec)

The model table will cover off different types of cars, it is going to be simpler for this to use different car types rather than actual car models.

mysql> create table models (id int(3) not null auto_increment primary key, 
    -> model varchar(15));
Query OK, 0 rows affected (0.01 sec)

mysql> show columns from models;
+-------+-------------+------+-----+---------+----------------+
| Field | Type        | Null | Key | Default | Extra          |
+-------+-------------+------+-----+---------+----------------+
| id    | int(3)      | NO   | PRI | NULL    | auto_increment |
| model | varchar(15) | YES  |     | NULL    |                |
+-------+-------------+------+-----+---------+----------------+
2 rows in set (0.00 sec)

mysql> insert into models (model) values ('Sports'), ('Sedan'), ('4WD'), ('Luxury');
Query OK, 4 rows affected (0.00 sec)
Records: 4  Duplicates: 0  Warnings: 0

mysql> select * from models;
+----+--------+
| id | model  |
+----+--------+
|  1 | Sports |
|  2 | Sedan  |
|  3 | 4WD    |
|  4 | Luxury |
+----+--------+
4 rows in set (0.00 sec)

And finally, to tie up all these other tables, the table that ties everything together. The ID field is actually the unique lot number used to identify cars.

mysql> create table cars (id int(3) not null auto_increment primary key, 
    -> color int(3), brand int(3), model int(3));
Query OK, 0 rows affected (0.01 sec)

mysql> show columns from cars;
+-------+--------+------+-----+---------+----------------+
| Field | Type   | Null | Key | Default | Extra          |
+-------+--------+------+-----+---------+----------------+
| id    | int(3) | NO   | PRI | NULL    | auto_increment |
| color | int(3) | YES  |     | NULL    |                |
| brand | int(3) | YES  |     | NULL    |                |
| model | int(3) | YES  |     | NULL    |                |
+-------+--------+------+-----+---------+----------------+
4 rows in set (0.00 sec)

mysql> insert into cars (color, brand, model) values (1,2,1), (3,1,2), (5,3,1), 
    -> (4,4,2), (2,2,3), (3,5,4), (4,1,3), (2,2,1), (5,2,3), (4,5,1);
Query OK, 10 rows affected (0.00 sec)
Records: 10  Duplicates: 0  Warnings: 0

mysql> select * from cars;
+----+-------+-------+-------+
| id | color | brand | model |
+----+-------+-------+-------+
|  1 |     1 |     2 |     1 |
|  2 |     3 |     1 |     2 |
|  3 |     5 |     3 |     1 |
|  4 |     4 |     4 |     2 |
|  5 |     2 |     2 |     3 |
|  6 |     3 |     5 |     4 |
|  7 |     4 |     1 |     3 |
|  8 |     2 |     2 |     1 |
|  9 |     5 |     2 |     3 |
| 10 |     4 |     5 |     1 |
+----+-------+-------+-------+
10 rows in set (0.00 sec)

This will give us enough data (I hope) to cover off the examples below of different types of joins and also give enough data to make them worthwhile.

So getting into the grit of it, the boss wants to know The IDs of all the sports cars he has.

This is a simple two table join. We have a table that identifies the model and the table with the available stock in it. As you can see, the data in the model column of the cars table relates to the models column of the cars table we have. Now, we know that the models table has an ID of 1 for Sports so lets write the join.

select
    ID,
    model
from
    cars
        join models
            on model=ID

So this query looks good right? We have identified the two tables and contain the information we need and use a join that correctly identifies what columns to join on.

ERROR 1052 (23000): Column 'ID' in field list is ambiguous

Oh noes! An error in our first query! Yes, and it is a plum. You see, the query has indeed got the right columns, but some of them exist in both tables, so the database gets confused about what actual column we mean and where. There are two solutions to solve this. The first is nice and simple, we can use tableName.columnName to tell the database exactly what we mean, like this:

select
    cars.ID,
    models.model
from
    cars
        join models
            on cars.model=models.ID

+----+--------+
| ID | model  |
+----+--------+
|  1 | Sports |
|  3 | Sports |
|  8 | Sports |
| 10 | Sports |
|  2 | Sedan  |
|  4 | Sedan  |
|  5 | 4WD    |
|  7 | 4WD    |
|  9 | 4WD    |
|  6 | Luxury |
+----+--------+
10 rows in set (0.00 sec)

The other is probably more often used and is called table aliasing. The tables in this example have nice and short simple names, but typing out something like KPI_DAILY_SALES_BY_DEPARTMENT would probably get old quickly, so a simple way is to nickname the table like this:

select
    a.ID,
    b.model
from
    cars a
        join models b
            on a.model=b.ID

Now, back to the request. As you can see we have the information we need, but we also have information that wasn't asked for, so we need to include a where clause in the statement to only get the Sports cars as was asked. As I prefer the table alias method rather than using the table names over and over, I will stick to it from this point onwards.

Clearly, we need to add a where clause to our query. We can identify Sports cars either by ID=1 or model='Sports'. As the ID is indexed and the primary key (and it happens to be less typing), lets use that in our query.

select
    a.ID,
    b.model
from
    cars a
        join models b
            on a.model=b.ID
where
    b.ID=1

+----+--------+
| ID | model  |
+----+--------+
|  1 | Sports |
|  3 | Sports |
|  8 | Sports |
| 10 | Sports |
+----+--------+
4 rows in set (0.00 sec)

Bingo! The boss is happy. Of course, being a boss and never being happy with what he asked for, he looks at the information, then says I want the colors as well.

Okay, so we have a good part of our query already written, but we need to use a third table which is colors. Now, our main information table cars stores the car color ID and this links back to the colors ID column. So, in a similar manner to the original, we can join a third table:

select
    a.ID,
    b.model
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
where
    b.ID=1

+----+--------+
| ID | model  |
+----+--------+
|  1 | Sports |
|  3 | Sports |
|  8 | Sports |
| 10 | Sports |
+----+--------+
4 rows in set (0.00 sec)

Damn, although the table was correctly joined and the related columns were linked, we forgot to pull in the actual information from the new table that we just linked.

select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
where
    b.ID=1

+----+--------+-------+
| ID | model  | color |
+----+--------+-------+
|  1 | Sports | Red   |
|  8 | Sports | Green |
| 10 | Sports | White |
|  3 | Sports | Black |
+----+--------+-------+
4 rows in set (0.00 sec)

Right, that's the boss off our back for a moment. Now, to explain some of this in a little more detail. As you can see, the from clause in our statement links our main table (I often use a table that contains information rather than a lookup or dimension table. The query would work just as well with the tables all switched around, but make less sense when we come back to this query to read it in a few months time, so it is often best to try to write a query that will be nice and easy to understand - lay it out intuitively, use nice indenting so that everything is as clear as it can be. If you go on to teach others, try to instill these characteristics in their queries - especially if you will be troubleshooting them.

It is entirely possible to keep linking more and more tables in this manner.

select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
        join brands d
            on a.brand=d.ID
where
    b.ID=1

While I forgot to include a table where we might want to join more than one column in the join statement, here is an example. If the models table had brand-specific models and therefore also had a column called brand which linked back to the brands table on the ID field, it could be done as this:

select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
        join brands d
            on a.brand=d.ID
            and b.brand=d.ID
where
    b.ID=1

You can see, the query above not only links the joined tables to the main cars table, but also specifies joins between the already joined tables. If this wasn't done, the result is called a cartesian join - which is dba speak for bad. A cartesian join is one where rows are returned because the information doesn't tell the database how to limit the results, so the query returns all the rows that fit the criteria.

So, to give an example of a cartesian join, lets run the following query:

select
    a.ID,
    b.model
from
    cars a
        join models b

+----+--------+
| ID | model  |
+----+--------+
|  1 | Sports |
|  1 | Sedan  |
|  1 | 4WD    |
|  1 | Luxury |
|  2 | Sports |
|  2 | Sedan  |
|  2 | 4WD    |
|  2 | Luxury |
|  3 | Sports |
|  3 | Sedan  |
|  3 | 4WD    |
|  3 | Luxury |
|  4 | Sports |
|  4 | Sedan  |
|  4 | 4WD    |
|  4 | Luxury |
|  5 | Sports |
|  5 | Sedan  |
|  5 | 4WD    |
|  5 | Luxury |
|  6 | Sports |
|  6 | Sedan  |
|  6 | 4WD    |
|  6 | Luxury |
|  7 | Sports |
|  7 | Sedan  |
|  7 | 4WD    |
|  7 | Luxury |
|  8 | Sports |
|  8 | Sedan  |
|  8 | 4WD    |
|  8 | Luxury |
|  9 | Sports |
|  9 | Sedan  |
|  9 | 4WD    |
|  9 | Luxury |
| 10 | Sports |
| 10 | Sedan  |
| 10 | 4WD    |
| 10 | Luxury |
+----+--------+
40 rows in set (0.00 sec)

Good god, that's ugly. However, as far as the database is concerned, it is exactly what was asked for. In the query, we asked for for the ID from cars and the model from models. However, because we didn't specify how to join the tables, the database has matched every row from the first table with every row from the second table.

Okay, so the boss is back, and he wants more information again. I want the same list, but also include 4WDs in it.

This however, gives us a great excuse to look at two different ways to accomplish this. We could add another condition to the where clause like this:

select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
        join brands d
            on a.brand=d.ID
where
    b.ID=1
    or b.ID=3

While the above will work perfectly well, lets look at it differently, this is a great excuse to show how a union query will work.

We know that the following will return all the Sports cars:

select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
        join brands d
            on a.brand=d.ID
where
    b.ID=1

And the following would return all the 4WDs:

select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
        join brands d
            on a.brand=d.ID
where
    b.ID=3

So by adding a union all clause between them, the results of the second query will be appended to the results of the first query.

select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
        join brands d
            on a.brand=d.ID
where
    b.ID=1
union all
select
    a.ID,
    b.model,
    c.color
from
    cars a
        join models b
            on a.model=b.ID
        join colors c
            on a.color=c.ID
        join brands d
            on a.brand=d.ID
where
    b.ID=3

+----+--------+-------+
| ID | model  | color |
+----+--------+-------+
|  1 | Sports | Red   |
|  8 | Sports | Green |
| 10 | Sports | White |
|  3 | Sports | Black |
|  5 | 4WD    | Green |
|  7 | 4WD    | White |
|  9 | 4WD    | Black |
+----+--------+-------+
7 rows in set (0.00 sec)

As you can see, the results of the first query are returned first, followed by the results of the second query.

In this example, it would of course have been much easier to simply use the first query, but union queries can be great for specific cases. They are a great way to return specific results from tables from tables that aren't easily joined together - or for that matter completely unrelated tables. There are a few rules to follow however.

  • The column types from the first query must match the column types from every other query below.
  • The names of the columns from the first query will be used to identify the entire set of results.
  • The number of columns in each query must be the same.

Now, you might be wondering what the difference is between using union and union all. A union query will remove duplicates, while a union all will not. This does mean that there is a small performance hit when using union over union all but the results may be worth it - I won't speculate on that sort of thing in this though.

On this note, it might be worth noting some additional notes here.

  • If we wanted to order the results, we can use an order by but you can't use the alias anymore. In the query above, appending an order by a.ID would result in an error - as far as the results are concerned, the column is called ID rather than a.ID - even though the same alias has been used in both queries.
  • We can only have one order by statement, and it must be as the last statement.

For the next examples, I am adding a few extra rows to our tables.

I have added Holden to the brands table. I have also added a row into cars that has the color value of 12 - which has no reference in the colors table.

Okay, the boss is back again, barking requests out - *I want a count of each brand we carry and the number of cars in it!` - Typical, we just get to an interesting section of our discussion and the boss wants more work.

Rightyo, so the first thing we need to do is get a complete listing of possible brands.

select
    a.brand
from
    brands a

+--------+
| brand  |
+--------+
| Ford   |
| Toyota |
| Nissan |
| Smart  |
| BMW    |
| Holden |
+--------+
6 rows in set (0.00 sec)

Now, when we join this to our cars table we get the following result:

select
    a.brand
from
    brands a
        join cars b
            on a.ID=b.brand
group by
    a.brand

+--------+
| brand  |
+--------+
| BMW    |
| Ford   |
| Nissan |
| Smart  |
| Toyota |
+--------+
5 rows in set (0.00 sec)

Which is of course a problem - we aren't seeing any mention of the lovely Holden brand I added.

This is because a join looks for matching rows in both tables. As there is no data in cars that is of type Holden it isn't returned. This is where we can use an outer join. This will return all the results from one table whether they are matched in the other table or not:

select
    a.brand
from
    brands a
        left outer join cars b
            on a.ID=b.brand
group by
    a.brand

+--------+
| brand  |
+--------+
| BMW    |
| Ford   |
| Holden |
| Nissan |
| Smart  |
| Toyota |
+--------+
6 rows in set (0.00 sec)

Now that we have that, we can add a lovely aggregate function to get a count and get the boss off our backs for a moment.

select
    a.brand,
    count(b.id) as countOfBrand
from
    brands a
        left outer join cars b
            on a.ID=b.brand
group by
    a.brand

+--------+--------------+
| brand  | countOfBrand |
+--------+--------------+
| BMW    |            2 |
| Ford   |            2 |
| Holden |            0 |
| Nissan |            1 |
| Smart  |            1 |
| Toyota |            5 |
+--------+--------------+
6 rows in set (0.00 sec)

And with that, away the boss skulks.

Now, to explain this in some more detail, outer joins can be of the left or right type. The Left or Right defines which table is fully included. A left outer join will include all the rows from the table on the left, while (you guessed it) a right outer join brings all the results from the table on the right into the results.

Some databases will allow a full outer join which will bring back results (whether matched or not) from both tables, but this isn't supported in all databases.

Now, I probably figure at this point in time, you are wondering whether or not you can merge join types in a query - and the answer is yes, you absolutely can.

select
    b.brand,
    c.color,
    count(a.id) as countOfBrand
from
    cars a
        right outer join brands b
            on b.ID=a.brand
        join colors c
            on a.color=c.ID
group by
    a.brand,
    c.color

+--------+-------+--------------+
| brand  | color | countOfBrand |
+--------+-------+--------------+
| Ford   | Blue  |            1 |
| Ford   | White |            1 |
| Toyota | Black |            1 |
| Toyota | Green |            2 |
| Toyota | Red   |            1 |
| Nissan | Black |            1 |
| Smart  | White |            1 |
| BMW    | Blue  |            1 |
| BMW    | White |            1 |
+--------+-------+--------------+
9 rows in set (0.00 sec)

So, why is that not the results that were expected? It is because although we have selected the outer join from cars to brands, it wasn't specified in the join to colors - so that particular join will only bring back results that match in both tables.

Here is the query that would work to get the results that we expected:

select
    a.brand,
    c.color,
    count(b.id) as countOfBrand
from
    brands a
        left outer join cars b
            on a.ID=b.brand
        left outer join colors c
            on b.color=c.ID
group by
    a.brand,
    c.color

+--------+-------+--------------+
| brand  | color | countOfBrand |
+--------+-------+--------------+
| BMW    | Blue  |            1 |
| BMW    | White |            1 |
| Ford   | Blue  |            1 |
| Ford   | White |            1 |
| Holden | NULL  |            0 |
| Nissan | Black |            1 |
| Smart  | White |            1 |
| Toyota | NULL  |            1 |
| Toyota | Black |            1 |
| Toyota | Green |            2 |
| Toyota | Red   |            1 |
+--------+-------+--------------+
11 rows in set (0.00 sec)

As we can see, we have two outer joins in the query and the results are coming through as expected.

Now, how about those other types of joins you ask? What about Intersections?

Well, not all databases support the intersection but pretty much all databases will allow you to create an intersection through a join (or a well structured where statement at the least).

An Intersection is a type of join somewhat similar to a union as described above - but the difference is that it only returns rows of data that are identical (and I do mean identical) between the various individual queries joined by the union. Only rows that are identical in every regard will be returned.

A simple example would be as such:

select
    *
from
    colors
where
    ID>2
intersect
select
    *
from
    colors
where
    id<4

While a normal union query would return all the rows of the table (the first query returning anything over ID>2 and the second anything having ID<4) which would result in a full set, an intersect query would only return the row matching id=3 as it meets both criteria.

Now, if your database doesn't support an intersect query, the above can be easily accomlished with the following query:

select
    a.ID,
    a.color,
    a.paint
from
    colors a
        join colors b
            on a.ID=b.ID
where
    a.ID>2
    and b.ID<4

+----+-------+----------+
| ID | color | paint    |
+----+-------+----------+
|  3 | Blue  | Metallic |
+----+-------+----------+
1 row in set (0.00 sec)

If you wish to perform an intersection across two different tables using a database that doesn't inherently support an intersection query, you will need to create a join on every column of the tables.

Excel- compare two cell from different sheet, if true copy value from other cell

In your destination field you want to use VLOOKUP like so:

=VLOOKUP(Sheet1!A1:A100,Sheet2!A1:F100,6,FALSE)

VLOOKUP Arguments:

  1. The set fields you want to lookup.
  2. The table range you want to lookup up your value against. The first column of your defined table should be the column you want compared against your lookup field. The table range should also contain the value you want to display (Column F).
  3. This defines what field you want to display upon a match.
  4. FALSE tells VLOOKUP to do an exact match.

Standard concise way to copy a file in Java?

Three possible problems with the above code:

  1. If getChannel throws an exception, you might leak an open stream.
  2. For large files, you might be trying to transfer more at once than the OS can handle.
  3. You are ignoring the return value of transferFrom, so it might be copying just part of the file.

This is why org.apache.tools.ant.util.ResourceUtils.copyResource is so complicated. Also note that while transferFrom is OK, transferTo breaks on JDK 1.4 on Linux (see Bug ID:5056395) – Jesse Glick Jan

Spring Maven clean error - The requested profile "pom.xml" could not be activated because it does not exist

I was getting this same warning everytime I was doing 'maven clean'. I found the solution :

Step - 1 Right click on your project in Eclipse

Step - 2 Click Properties

Step - 3 Select Maven in the left hand side list.

Step - 4 You will notice "pom.xml" in the Active Maven Profiles text box on the right hand side. Clear it and click Apply.

Below is the screen shot :

Properties dialog box

Hope this helps. :)

Concatenate two string literals

Since C++14 you can use two real string literals:

const string hello = "Hello"s;

const string message = hello + ",world"s + "!"s;

or

const string exclam = "!"s;

const string message = "Hello"s + ",world"s + exclam;

WebView and HTML5 <video>

A-M's is similar to what the BrowerActivity does. for FrameLayout.LayoutParams LayoutParameters = new FrameLayout.LayoutParams (768, 512);

I think we can use

FrameLayout.LayoutParams LayoutParameters = new FrameLayout.LayoutParams(FrameLayout.LayoutParams.FILL_PARENT,
            FrameLayout.LayoutParams.FILL_PARENT) 

instead.

Another issue I met is if the video is playing, and user clicks the back button, next time, you go to this activity(singleTop one) and can not play the video. to fix this, I called the

try { 
    mCustomVideoView.stopPlayback();  
    mCustomViewCallback.onCustomViewHidden();
} catch(Throwable e) { //ignore }

in the activity's onBackPressed method.

RegEx match open tags except XHTML self-contained tags

I agree that the right tool to parse XML and especially HTML is a parser and not a regular expression engine. However, like others have pointed out, sometimes using a regex is quicker, easier, and gets the job done if you know the data format.

Microsoft actually has a section of Best Practices for Regular Expressions in the .NET Framework and specifically talks about Consider[ing] the Input Source.

Regular Expressions do have limitations, but have you considered the following?

The .NET framework is unique when it comes to regular expressions in that it supports Balancing Group Definitions.

For this reason, I believe you CAN parse XML using regular expressions. Note however, that it must be valid XML (browsers are very forgiving of HTML and allow bad XML syntax inside HTML). This is possible since the "Balancing Group Definition" will allow the regular expression engine to act as a PDA.

Quote from article 1 cited above:

.NET Regular Expression Engine

As described above properly balanced constructs cannot be described by a regular expression. However, the .NET regular expression engine provides a few constructs that allow balanced constructs to be recognized.

  • (?<group>) - pushes the captured result on the capture stack with the name group.
  • (?<-group>) - pops the top most capture with the name group off the capture stack.
  • (?(group)yes|no) - matches the yes part if there exists a group with the name group otherwise matches no part.

These constructs allow for a .NET regular expression to emulate a restricted PDA by essentially allowing simple versions of the stack operations: push, pop and empty. The simple operations are pretty much equivalent to increment, decrement and compare to zero respectively. This allows for the .NET regular expression engine to recognize a subset of the context-free languages, in particular the ones that only require a simple counter. This in turn allows for the non-traditional .NET regular expressions to recognize individual properly balanced constructs.

Consider the following regular expression:

(?=<ul\s+id="matchMe"\s+type="square"\s*>)
(?>
   <!-- .*? -->                  |
   <[^>]*/>                      |
   (?<opentag><(?!/)[^>]*[^/]>)  |
   (?<-opentag></[^>]*[^/]>)     |
   [^<>]*
)*
(?(opentag)(?!))

Use the flags:

  • Singleline
  • IgnorePatternWhitespace (not necessary if you collapse regex and remove all whitespace)
  • IgnoreCase (not necessary)

Regular Expression Explained (inline)

(?=<ul\s+id="matchMe"\s+type="square"\s*>) # match start with <ul id="matchMe"...
(?>                                        # atomic group / don't backtrack (faster)
   <!-- .*? -->                 |          # match xml / html comment
   <[^>]*/>                     |          # self closing tag
   (?<opentag><(?!/)[^>]*[^/]>) |          # push opening xml tag
   (?<-opentag></[^>]*[^/]>)    |          # pop closing xml tag
   [^<>]*                                  # something between tags
)*                                         # match as many xml tags as possible
(?(opentag)(?!))                           # ensure no 'opentag' groups are on stack

You can try this at A Better .NET Regular Expression Tester.

I used the sample source of:

<html>
<body>
<div>
   <br />
   <ul id="matchMe" type="square">
      <li>stuff...</li>
      <li>more stuff</li>
      <li>
          <div>
               <span>still more</span>
               <ul>
                    <li>Another &gt;ul&lt;, oh my!</li>
                    <li>...</li>
               </ul>
          </div>
      </li>
   </ul>
</div>
</body>
</html>

This found the match:

   <ul id="matchMe" type="square">
      <li>stuff...</li>
      <li>more stuff</li>
      <li>
          <div>
               <span>still more</span>
               <ul>
                    <li>Another &gt;ul&lt;, oh my!</li>
                    <li>...</li>
               </ul>
          </div>
      </li>
   </ul>

although it actually came out like this:

<ul id="matchMe" type="square">           <li>stuff...</li>           <li>more stuff</li>           <li>               <div>                    <span>still more</span>                    <ul>                         <li>Another &gt;ul&lt;, oh my!</li>                         <li>...</li>                    </ul>               </div>           </li>        </ul>

Lastly, I really enjoyed Jeff Atwood's article: Parsing Html The Cthulhu Way. Funny enough, it cites the answer to this question that currently has over 4k votes.

Disable click outside of angular material dialog area to close the dialog (With Angular Version 4.0+)

There are two ways to do it.

  1. In the method that opens the dialog, pass in the following configuration option disableClose as the second parameter in MatDialog#open() and set it to true:

    export class AppComponent {
      constructor(private dialog: MatDialog){}
      openDialog() {
        this.dialog.open(DialogComponent, { disableClose: true });
      }
    }
    
  2. Alternatively, do it in the dialog component itself.

    export class DialogComponent {
      constructor(private dialogRef: MatDialogRef<DialogComponent>){
        dialogRef.disableClose = true;
      }
    }
    

Here's what you're looking for:

<code>disableClose</code> property in material.angular.io

And here's a Stackblitz demo


Other use cases

Here's some other use cases and code snippets of how to implement them.

Allow esc to close the dialog but disallow clicking on the backdrop to close the dialog

As what @MarcBrazeau said in the comment below my answer, you can allow the esc key to close the modal but still disallow clicking outside the modal. Use this code on your dialog component:

import { Component, OnInit, HostListener } from '@angular/core';
import { MatDialogRef } from '@angular/material';
@Component({
  selector: 'app-third-dialog',
  templateUrl: './third-dialog.component.html'
})
export class ThirdDialogComponent {
  constructor(private dialogRef: MatDialogRef<ThirdDialogComponent>) {      
}
  @HostListener('window:keyup.esc') onKeyUp() {
    this.dialogRef.close();
  }

}

Prevent esc from closing the dialog but allow clicking on the backdrop to close

P.S. This is an answer which originated from this answer, where the demo was based on this answer.

To prevent the esc key from closing the dialog but allow clicking on the backdrop to close, I've adapted Marc's answer, as well as using MatDialogRef#backdropClick to listen for click events to the backdrop.

Initially, the dialog will have the configuration option disableClose set as true. This ensures that the esc keypress, as well as clicking on the backdrop will not cause the dialog to close.

Afterwards, subscribe to the MatDialogRef#backdropClick method (which emits when the backdrop gets clicked and returns as a MouseEvent).

Anyways, enough technical talk. Here's the code:

openDialog() {
  let dialogRef = this.dialog.open(DialogComponent, { disableClose: true });
  /*
     Subscribe to events emitted when the backdrop is clicked
     NOTE: Since we won't actually be using the `MouseEvent` event, we'll just use an underscore here
     See https://stackoverflow.com/a/41086381 for more info
  */
  dialogRef.backdropClick().subscribe(() => {
    // Close the dialog
    dialogRef.close();
  })

  // ...
}

Alternatively, this can be done in the dialog component:

export class DialogComponent {
  constructor(private dialogRef: MatDialogRef<DialogComponent>) {
    dialogRef.disableClose = true;
    /*
      Subscribe to events emitted when the backdrop is clicked
      NOTE: Since we won't actually be using the `MouseEvent` event, we'll just use an underscore here
      See https://stackoverflow.com/a/41086381 for more info
    */
    dialogRef.backdropClick().subscribe(() => {
      // Close the dialog
      dialogRef.close();
    })
  }
}

Java 32-bit vs 64-bit compatibility

I accidentally ran our (largeish) application on a 64bit VM rather than a 32bit VM and didn't notice until some external libraries (called by JNI) started failing.

Data serialized on a 32bit platform was read in on the 64bit platform with no issues at all.

What sort of issues are you getting? Do some things work and not others? Have you tried attaching JConsole etc and have a peak around?

If you have a very big VM you may find that GC issues in 64 bit can affect you.

Align printf output in Java

Here's a potential solution that will set the width of the bookType column (i.e. format of the bookTypes value) based on the longest bookTypes value.

public class Test {
    public static void main(String[] args) {
        String[] bookTypes = { "Newspaper", "Paper Back", "Hardcover book", "Electronic book", "Magazine" };
        double[] costs = { 1.0, 7.5, 10.0, 2.0, 3.0 };

        // Find length of longest bookTypes value.
        int maxLengthItem = 0;
        boolean firstValue = true;
        for (String bookType : bookTypes) {
            maxLengthItem = (firstValue) ? bookType.length() : Math.max(maxLengthItem, bookType.length());
            firstValue = false;
        }

        // Display rows of data
        for (int i = 0; i < bookTypes.length; i++) {
            // Use %6.2 instead of %.2 so that decimals line up, assuming max
            // book cost of $999.99. Change 6 to a different number if max cost
            // is different
            String format = "%d. %-" + Integer.toString(maxLengthItem) + "s \t\t $%9.2f\n";
            System.out.printf(format, i + 1, bookTypes[i], costs[i]);
        }
    }
}

What is the equivalent to a JavaScript setInterval/setTimeout in Android/Java?

Depending on what you actually want to achieve, you should take a look at Android Handlers:

http://developer.android.com/reference/android/os/Handler.html

If you previously used javascript setTimeout() etc to schedule a task to run in the future, this is the Android way of doing it (postDelayed / sendMessageDelayed).

Note that neither Handlers or Timers makes an Android phone wake up from sleep mode. In other words, if you want to schedule something to actually happen even though the screen is off / cpu is sleeping, you need to check out the AlarmManager too.

Javascript - Regex to validate date format

To make sure it will work, you need to validate it.

function mmIsDate(str) {

    if (str == undefined) { return false; }

    var parms = str.split(/[\.\-\/]/);

    var yyyy = parseInt(parms[2], 10);

    if (yyyy < 1900) { return false; }

    var mm = parseInt(parms[1], 10);
    if (mm < 1 || mm > 12) { return false; }

    var dd = parseInt(parms[0], 10);
    if (dd < 1 || dd > 31) { return false; }

    var dateCheck = new Date(yyyy, mm - 1, dd);
    return (dateCheck.getDate() === dd && (dateCheck.getMonth() === mm - 1) && dateCheck.getFullYear() === yyyy);

};

Load external css file like scripts in jquery which is compatible in ie also

    //load css first, then print <link> to header, and execute callback
    //just set var href above this..
    $.ajax({
          url: href,
          dataType: 'css',
          success: function(){                  
                $('<link rel="stylesheet" type="text/css" href="'+href+'" />').appendTo("head");
                //your callback
            }
    });

For Jquery 1.2.6 and above ( omitting the fancy attributes functions above ).

I am doing it this way because I think that this will ensure that your requested stylesheet is loaded by ajax before you try to stick it into the head. Therefore, the callback is executed after the stylesheet is ready.

How can I check whether Google Maps is fully loaded?

In 2018:

var map = new google.maps.Map(...)
map.addListener('tilesloaded', function () { ... })

https://developers.google.com/maps/documentation/javascript/events

Accessing a resource via codebehind in WPF

You can use a resource key like this:

<UserControl.Resources>
    <SolidColorBrush x:Key="{x:Static local:Foo.MyKey}">Blue</SolidColorBrush>
</UserControl.Resources>
<Grid Background="{StaticResource {x:Static local:Foo.MyKey}}" />

public partial class Foo : UserControl
{
    public Foo()
    {
        InitializeComponent();
        var brush = (SolidColorBrush)FindResource(MyKey);
    }

    public static ResourceKey MyKey { get; } = CreateResourceKey();

    private static ComponentResourceKey CreateResourceKey([CallerMemberName] string caller = null)
    {
        return new ComponentResourceKey(typeof(Foo), caller); ;
    }
}

Add an image in a WPF button

I also had the same issue. I've fixed it by using the following code.

        <Button Width="30" Margin="0,5" HorizontalAlignment="Stretch"  Click="OnSearch" >
            <DockPanel>
                <Image Source="../Resources/Back.jpg"/>
            </DockPanel>
        </Button>

Note: Make sure the build action of the image in the property window, should be Resource.

enter image description here

Google Maps API v3: Can I setZoom after fitBounds?

this work's for me with API v3 but with setting fixed zoom:

var bounds = new google.maps.LatLngBounds();
// extend bounds with each point

gmap.setCenter(bounds.getCenter()); 
gmap.setZoom( 6 );

do { ... } while (0) — what is it good for?

It helps to group multiple statements into a single one so that a function-like macro can actually be used as a function. Suppose you have:

#define FOO(n)   foo(n);bar(n)

and you do:

void foobar(int n) {
  if (n)
     FOO(n);
}

then this expands to:

void foobar(int n) {
  if (n)
     foo(n);bar(n);
}

Notice that the second call bar(n) is not part of the if statement anymore.

Wrap both into do { } while(0), and you can also use the macro in an if statement.

How to determine when a Git branch was created?

Use:

git reflog

to show all the living cycle of your repository in current folder. The branch name that first appear (from down to up) is the source that was created.

855a3ce HEAD@{0}: checkout: moving from development to feature-sut-46
855a3ce HEAD@{1}: checkout: moving from feature-sut-46 to development
855a3ce HEAD@{2}: checkout: moving from feature-jira35 to feature-sut-46
535dd9d HEAD@{3}: checkout: moving from feature-sut-46 to feature-jira35
855a3ce HEAD@{4}: checkout: moving from development to feature-sut-46
855a3ce HEAD@{5}: checkout: moving from feature-jira35 to development
535dd9d HEAD@{6}: commit: insert the format for vendor specific brower - screen.css
855a3ce HEAD@{7}: checkout: moving from development to feature-jira35
855a3ce HEAD@{8}: checkout: moving from master to development

That mean:

  • Branch development is created (checkout -b) from master

  • Branch feature-jira35 is created (checkout -b) from development

  • Branch feature-jira-sut-46 is created (checkout -b) from development

How do I get the domain originating the request in express.js?

In Express 4.x you can use req.hostname, which returns the domain name, without port. i.e.:

// Host: "example.com:3000"
req.hostname
// => "example.com"

See: http://expressjs.com/en/4x/api.html#req.hostname

PHP header redirect 301 - what are the implications?

Just a tip: using http_response_code is much easier to remember than writing the full header:

http_response_code(301);
header('Location: /option-a'); 
exit;

How to select a CRAN mirror in R

I used

chooseCRANmirror(81)

it gives you a prompt to select the country. Then you can do a selection by typing the country mirror code specified there.

How to get value in the session in jQuery

Assuming you are using this plugin, you are misusing the .set method. .set must be passed the name of the key as a string as well as the value. I suppose you meant to write:

$.session.set("userName", $("#uname").val());

This sets the userName key in session storage to the value of the input, and allows you to retrieve it using:

$.session.get('userName');

Error while trying to run project: Unable to start program. Cannot find the file specified

I had the same problem.
The cause for me was that the Command option in Configuration Properties | Debugging had been reset to its default value.

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

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

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

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

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

Filter array to have unique values

As of June 15, 2015 you may use Set() to create a unique array:

var uniqueArray = [...new Set(array)]

For your Example:

var data = ["X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11"]
var newArray = [...new Set(data)]
console.log(newArray)

>> ["X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11"]

how to save DOMPDF generated content to file?

<?php
$content='<table width="100%" border="1">';
$content.='<tr><th>name</th><th>email</th><th>contact</th><th>address</th><th>city</th><th>country</th><th>postcode</th></tr>';
for ($index = 0; $index < 10; $index++) { 
$content.='<tr><td>nadim</td><td>[email protected]</td><td>7737033665</td><td>247 dehligate</td><td>udaipur</td><td>india</td><td>313001</td></tr>';
}
$content.='</table>';
//$html = file_get_contents('pdf.php');
if(isset($_POST['pdf'])){
    require_once('./dompdf/dompdf_config.inc.php');
    $dompdf = new DOMPDF;                        
    $dompdf->load_html($content);
    $dompdf->render();
    $dompdf->stream("hello.pdf");
}
?>
<html>
    <body>
        <form action="#" method="post">        
            <button name="pdf" type="submit">export</button>
        <table width="100%" border="1">
           <tr><th>name</th><th>email</th><th>contact</th><th>address</th><th>city</th><th>country</th><th>postcode</th></tr>         
            <?php for ($index = 0; $index < 10; $index++) { ?>
            <tr><td>nadim</td><td>[email protected]</td><td>7737033665</td><td>247 dehligate</td><td>udaipur</td><td>india</td><td>313001</td></tr>
            <?php } ?>            
        </table>        
        </form>        
    </body>
</html>

How to run a python script from IDLE interactive shell?

Python3:

exec(open('helloworld.py').read())

If your file not in the same dir:

exec(open('./app/filename.py').read())

See https://stackoverflow.com/a/437857/739577 for passing global/local variables.


In deprecated Python versions

Python2 Built-in function: execfile

execfile('helloworld.py')

It normally cannot be called with arguments. But here's a workaround:

import sys
sys.argv = ['helloworld.py', 'arg']  # argv[0] should still be the script name
execfile('helloworld.py')

Deprecated since 2.6: popen

import os
os.popen('python helloworld.py') # Just run the program
os.popen('python helloworld.py').read() # Also gets you the stdout

With arguments:

os.popen('python helloworld.py arg').read()

Advance usage: subprocess

import subprocess
subprocess.call(['python', 'helloworld.py']) # Just run the program
subprocess.check_output(['python', 'helloworld.py']) # Also gets you the stdout

With arguments:

subprocess.call(['python', 'helloworld.py', 'arg'])

Read the docs for details :-)


Tested with this basic helloworld.py:

import sys
if len(sys.argv) > 1:
    print(sys.argv[1])

data.table vs dplyr: can one do something well the other can't or does poorly?

Reading Hadley and Arun's answers one gets the impression that those who prefer dplyr's syntax would have in some cases to switch over to data.table or compromise for long running times.

But as some have already mentioned, dplyr can use data.table as a backend. This is accomplished using the dtplyr package which recently had it's version 1.0.0 release. Learning dtplyr incurs practically zero additional effort.

When using dtplyr one uses the function lazy_dt() to declare a lazy data.table, after which standard dplyr syntax is used to specify operations on it. This would look something like the following:

new_table <- mtcars2 %>% 
  lazy_dt() %>%
  filter(wt < 5) %>% 
  mutate(l100k = 235.21 / mpg) %>% # liters / 100 km
  group_by(cyl) %>% 
  summarise(l100k = mean(l100k))

  new_table

#> Source: local data table [?? x 2]
#> Call:   `_DT1`[wt < 5][, `:=`(l100k = 235.21/mpg)][, .(l100k = mean(l100k)), 
#>     keyby = .(cyl)]
#> 
#>     cyl l100k
#>   <dbl> <dbl>
#> 1     4  9.05
#> 2     6 12.0 
#> 3     8 14.9 
#> 
#> # Use as.data.table()/as.data.frame()/as_tibble() to access results

The new_table object is not evaluated until calling on it as.data.table()/as.data.frame()/as_tibble() at which point the underlying data.table operation is executed.

I've recreated a benchmark analysis done by data.table author Matt Dowle back at December 2018 which covers the case of operations over large numbers of groups. I've found that dtplyr indeed enables for the most part those who prefer the dplyr syntax to keep using it while enjoying the speed offered by data.table.

How can I find a file/directory that could be anywhere on linux command line?

I hope this comment will help you to find out your local & server file path using terminal

 find "$(cd ..; pwd)" -name "filename"

Or just you want to see your Current location then run

 pwd "filename"

Select default option value from typescript angular 6

HTML

<select class='form-control'>
    <option *ngFor="let option of options"
    [selected]="option === nrSelect"
    [value]="option">
        {{ option }}
    </option>
</select>

Typescript

nrSelect = 47;
options = [41, 42, 47, 48];

How to re-index all subarray elements of a multidimensional array?

Here you can see the difference between the way that deceze offered comparing to the simple array_values approach:

The Array:

$array['a'][0] = array('x' => 1, 'y' => 2, 'z' => 3);
$array['a'][5] = array('x' => 4, 'y' => 5, 'z' => 6);

$array['b'][1] = array('x' => 7, 'y' => 8, 'z' => 9);
$array['b'][7] = array('x' => 10, 'y' => 11, 'z' => 12);

In deceze way, here is your output:

$array = array_map('array_values', $array);
print_r($array);

/* Output */

Array
(
    [a] => Array
        (
            [0] => Array
                (
                    [x] => 1
                    [y] => 2
                    [z] => 3
                )
            [1] => Array
                (
                    [x] => 4
                    [y] => 5
                    [z] => 6
                )
        )
    [b] => Array
        (
            [0] => Array
                (
                    [x] => 7
                    [y] => 8
                    [z] => 9
                )

            [1] => Array
                (
                    [x] => 10
                    [y] => 11
                    [z] => 12
                )
        )
)

And here is your output if you only use array_values function:

$array = array_values($array);
print_r($array);

/* Output */

Array
(
    [0] => Array
        (
            [0] => Array
                (
                    [x] => 1
                    [y] => 2
                    [z] => 3
                )
            [5] => Array
                (
                    [x] => 4
                    [y] => 5
                    [z] => 6
                )
        )
    [1] => Array
        (
            [1] => Array
                (
                    [x] => 7
                    [y] => 8
                    [z] => 9
                )
            [7] => Array
                (
                    [x] => 10
                    [y] => 11
                    [z] => 12
                )
        )
)

How to keep one variable constant with other one changing with row in excel

Yeah. Just put the $ sign in front of your desired constant cell.

Like $A6 if you wish to just change the number 6 serially and keep a constant, or $A$6 if you do not want anything from that reference to change at all.

Example: Cell A5 contains my exchange rate. In B1 you put say ( = C1 * $A$1). when you fill B1 through B....... the value in A5 remains constant and the value in C1 increases serially.

I am by far not be good at teacher, but I hope this helps!!!! Wink wink

Changing the background color of a drop down list transparent in html

Or maybe

 background: transparent !important;
 color: #ffffff;

How to open a page in a new window or tab from code-behind

This code works for me:

Dim script As String = "<script type=""text/javascript"">window.open('" & URL.ToString & "');</script>"
ClientScript.RegisterStartupScript(Me.GetType, "openWindow", script)

Android view pager with page indicator

I know this has already been answered, but for anybody looking for a simple, no-frills implementation of a ViewPager indicator, I've implemented one that I've open sourced. For anyone finding Jake Wharton's version a bit complex for their needs, have a look at https://github.com/jarrodrobins/SimpleViewPagerIndicator.

Adding Table rows Dynamically in Android

You also can, as Fredigato said, declare a RelativeLayout in a separate Layout file. Then instantiate it using:

for(int i = 0; i < 6; i ++){
LayoutInflater inflater = (LayoutInflater)getApplicationContext().getSystemService
                (Context.LAYOUT_INFLATER_SERVICE);
RelativeLayout row = (RelativeLayout) inflater.inflate(R.layout.table_view,null);
        quizesTableLayout.addView(row,i);
}

In this approach you can easily design one custom row using XML and reuse it.

Now, to be able to change the children views in the instantiated RelativeLayout. You can call row.childAt(index).

So lets say you have a TextView in the RelativeLayout, you can use:

TextView tv = (TextView) row.childAt(0);
tv.setText("Text");

PreparedStatement with list of parameters in a IN clause

Currently, MySQL doesn't allow to set multiple values in one method call. So you have to have it under your own control. I usually create one prepared statement for predefined number of parameters, then I add as many batches as I need.

    int paramSizeInClause = 10; // required to be greater than 0!
    String color = "FF0000"; // red
    String name = "Nathan"; 
    Date now = new Date();
    String[] ids = "15,21,45,48,77,145,158,321,325,326,327,328,329,330,331,332,333,334,335,336,337,338,339,340,341,342,343,344,345,346,347,348,349,350,351,358,1284,1587".split(",");

    // Build sql query 
    StringBuilder sql = new StringBuilder();
    sql.append("UPDATE book SET color=? update_by=?, update_date=? WHERE book_id in (");
    // number of max params in IN clause can be modified 
    // to get most efficient combination of number of batches
    // and number of parameters in each batch
    for (int n = 0; n < paramSizeInClause; n++) {
        sql.append("?,");
    }
    if (sql.length() > 0) {
        sql.deleteCharAt(sql.lastIndexOf(","));
    }
    sql.append(")");

    PreparedStatement pstm = null;
    try {
        pstm = connection.prepareStatement(sql.toString());
        int totalIdsToProcess = ids.length;
        int batchLoops = totalIdsToProcess / paramSizeInClause + (totalIdsToProcess % paramSizeInClause > 0 ? 1 : 0);
        for (int l = 0; l < batchLoops; l++) {
            int i = 1;
            pstm.setString(i++, color);
            pstm.setString(i++, name);
            pstm.setTimestamp(i++, new Timestamp(now.getTime()));
            for (int count = 0; count < paramSizeInClause; count++) {
                int param = (l * paramSizeInClause + count);
                if (param < totalIdsToProcess) {
                    pstm.setString(i++, ids[param]);
                } else {
                    pstm.setNull(i++, Types.VARCHAR);
                }
            }
            pstm.addBatch();
        }
    } catch (SQLException e) {
    } finally {
        //close statement(s)
    }

If you don't like to set NULL when no more parameters left, you can modify code to build two queries and two prepared statements. First one is the same, but second statement for the remainder (modulus). In this particular example that would be one query for 10 params and one for 8 params. You will have to add 3 batches for the first query (first 30 params) then one batch for the second query (8 params).

How to retrieve an Oracle directory path?

The ALL_DIRECTORIES data dictionary view will have information about all the directories that you have access to. That includes the operating system path

SELECT owner, directory_name, directory_path
  FROM all_directories

How to set CATALINA_HOME variable in windows 7?

In order to set CATALINA_HOME:

  1. First, unzip and paste the apache-tomcat-7.1.100 folder in your C:// drive folder.

NOTE: Do not place your apache tomcat folder within any other folder or drive, place it directly in C:// drive folder only. (I did this mistake and none of the above-mentioned solutions were working).

  1. Open environment variable dialog box (windows key+ pause-break key --> advanced setting).

  2. Add a new variable name as "CATALINA_HOME" and add the variable path as "C://apache-tomcat-7.1.100"(as in my case), in System Variables.

  3. Edit PATH variable name add "%CATALINA_HOME%\bin" and press OK.

  4. Close the window and it will be saved.

  5. Open Command Prompt window and type command- "%CATALINA_HOME%\bin\startup.bat" to run and start the Tomcat server.

  6. END!

Format date to MM/dd/yyyy in JavaScript

All other answers don't quite solve the issue. They print the date formatted as mm/dd/yyyy but the question was regarding MM/dd/yyyy. Notice the subtle difference? MM indicates that a leading zero must pad the month if the month is a single digit, thus having it always be a double digit number.

i.e. whereas mm/dd would be 3/31, MM/dd would be 03/31.

I've created a simple function to achieve this. Notice that the same padding is applied not only to the month but also to the day of the month, which in fact makes this MM/DD/yyyy:

_x000D_
_x000D_
function getFormattedDate(date) {_x000D_
  var year = date.getFullYear();_x000D_
_x000D_
  var month = (1 + date.getMonth()).toString();_x000D_
  month = month.length > 1 ? month : '0' + month;_x000D_
_x000D_
  var day = date.getDate().toString();_x000D_
  day = day.length > 1 ? day : '0' + day;_x000D_
  _x000D_
  return month + '/' + day + '/' + year;_x000D_
}
_x000D_
_x000D_
_x000D_


Update for ES2017 using String.padStart(), supported by all major browsers except IE.

_x000D_
_x000D_
function getFormattedDate(date) {_x000D_
    let year = date.getFullYear();_x000D_
    let month = (1 + date.getMonth()).toString().padStart(2, '0');_x000D_
    let day = date.getDate().toString().padStart(2, '0');_x000D_
  _x000D_
    return month + '/' + day + '/' + year;_x000D_
}
_x000D_
_x000D_
_x000D_

Replace all particular values in a data frame

Since PikkuKatja and glallen asked for a more general solution and I cannot comment yet, I'll write an answer. You can combine statements as in:

> df[df=="" | df==12] <- NA
> df
     A    B
1  <NA> <NA>
2  xyz  <NA>
3  jkl  100

For factors, zxzak's code already yields factors:

> df <- data.frame(list(A=c("","xyz","jkl"), B=c(12,"",100)))
> str(df)
'data.frame':   3 obs. of  2 variables:
 $ A: Factor w/ 3 levels "","jkl","xyz": 1 3 2
 $ B: Factor w/ 3 levels "","100","12": 3 1 2

If in trouble, I'd suggest to temporarily drop the factors.

df[] <- lapply(df, as.character)

SQL "between" not inclusive

your code

SELECT * FROM Cases WHERE created_at BETWEEN '2013-05-01' AND '2013-05-01'

how SQL reading it

SELECT * FROM Cases WHERE '2013-05-01 22:25:19' BETWEEN '2013-05-01 00:00:00' AND '2013-05-01 00:00:00'

if you don't mention time while comparing DateTime and Date by default hours:minutes:seconds will be zero in your case dates are the same but if you compare time created_at is 22 hours ahead from your end date range

if the above is clear you fix this in many ways like putting ending hours in your end date eg BETWEEN '2013-05-01' AND ''2013-05-01 23:59:59''

OR

simply cast create_at as date like cast(created_at as date) after casting as date '2013-05-01 22:25:19' will be equal to '2013-05-01 00:00:00'

How to reload/refresh jQuery dataTable?

This is how I do it... Maybe not the best way, but it's definitely simpler (IMHO) and doesn't require any additional plugins.

HTML

<div id="my-datatable"></div>

jQuery

function LoadData() {
    var myDataTable = $("#my-datatable").html("<table><thead></thead><tbody></tbody></table>");
    $("table",myDataTable).dataTable({...});
}
$(document).ready(function() {
    $("#my-button").click(LoadData);
    LoadData();
});

Note: In my workings with jQuery dataTable, sometimes if you don't have <thead></thead><tbody></tbody> it doesn't work. But you might be able to get by without it. I haven't exactly figured out what makes it required and what doesn't.

How do I get just the date when using MSSQL GetDate()?

SELECT CONVERT(DATETIME, CONVERT(varchar(10), GETDATE(), 101))

Extract digits from string - StringUtils Java

        String line = "This order was32354 placed for QT ! OK?";
        String regex = "[^\\d]+";

        String[] str = line.split(regex);

        System.out.println(str[1]);

How to convert CharSequence to String?

There is a subtle issue here that is a bit of a gotcha.

The toString() method has a base implementation in Object. CharSequence is an interface; and although the toString() method appears as part of that interface, there is nothing at compile-time that will force you to override it and honor the additional constraints that the CharSequence toString() method's javadoc puts on the toString() method; ie that it should return a string containing the characters in the order returned by charAt().

Your IDE won't even help you out by reminding that you that you probably should override toString(). For example, in intellij, this is what you'll see if you create a new CharSequence implementation: http://puu.sh/2w1RJ. Note the absence of toString().

If you rely on toString() on an arbitrary CharSequence, it should work provided the CharSequence implementer did their job properly. But if you want to avoid any uncertainty altogether, you should use a StringBuilder and append(), like so:

final StringBuilder sb = new StringBuilder(charSequence.length());
sb.append(charSequence);
return sb.toString();

How do I conditionally add attributes to React components?

Here is an alternative.

var condition = true;

var props = {
  value: 'foo',
  ...( condition && { disabled: true } )
};

var component = <div { ...props } />;

Or its inline version

var condition = true;

var component = (
  <div
    value="foo"
    { ...( condition && { disabled: true } ) } />
);

Difference between RUN and CMD in a Dockerfile

There has been enough answers on RUN and CMD. I just want to add a few words on ENTRYPOINT. CMD arguments can be overwritten by command line arguments, while ENTRYPOINT arguments are always used.

This article is a good source of information.

Pass data to layout that are common to all pages

It's incredible that nobody has said this over here. Passing a viewmodel through a base controller is a mess. We are using user claims to pass info to the layout page (for showing user data on the navbar for example). There is one more advantage. The data is stored via cookies, so there is no need to retrieve the data in each request via partials. Just do some googling "asp net identity claims".

Shorter syntax for casting from a List<X> to a List<Y>?

This is not quite the answer to this question, but it may be useful for some: as @SWeko said, thanks to covariance and contravariance, List<X> can not be cast in List<Y>, but List<X> can be cast into IEnumerable<Y>, and even with implicit cast.

Example:

List<Y> ListOfY = new List<Y>();
List<X> ListOfX = (List<X>)ListOfY; // Compile error

but

List<Y> ListOfY = new List<Y>();
IEnumerable<X> EnumerableOfX = ListOfY;  // No issue

The big advantage is that it does not create a new list in memory.

SQL Delete Records within a specific Range

If you write it as the following in SQL server then there would be no danger of wiping the database table unless all of the values in that table happen to actually be between those values:

DELETE FROM [dbo].[TableName] WHERE [TableName].[IdField] BETWEEN 79 AND 296 

iOS 10 - Changes in asking permissions of Camera, microphone and Photo Library causing application to crash

You have to add this permission in Info.plist for iOS 10.

Photo :

Key       :  Privacy - Photo Library Usage Description    
Value   :  $(PRODUCT_NAME) photo use

Microphone :

Key        :  Privacy - Microphone Usage Description    
Value    :  $(PRODUCT_NAME) microphone use

Camera :

Key       :  Privacy - Camera Usage Description   
Value   :  $(PRODUCT_NAME) camera use

How to stop tracking and ignore changes to a file in Git?

To save some time the rules you add to your .gitignore can be used for removing multiple files/folders i.e.

git rm --cached app/**/*.xml

or

git rm --cached -r app/widgets/yourfolder/

e.t.c.

Add inline style using Javascript

you should make a css class .my_style then use .addClass('.mystyle')

Styling input radio with css

You should use some background image to your radio buttons and flip it with another image on change

.radio {
    background: url(customButton.png) no-repeat;
}

Traversing text in Insert mode

Many people in the Vim community argue that you should not navigate in Insert mode, that it is not the Vim way. I think this is an incorrect sentiment learned when transitioning from standard editors to Vim.

Vim is most powerful when you use its tools to create atomic, repeatable actions or finds.

It is ok to navigate while in Insert mode if you are fixing a mistake you made in the same Insert session. You should not navigate outside of the range of text you modified.

If you make a mistake while entering text and escape out of Insert mode to fix it you will not be able to repeat the intended action, . will repeat the correction.

Vim does support many Insert mode navigation keys. Obviously there are the arrow keys, Home, and End, but there are also many other shortcuts. See :h ins-special-keys.

Sending HTML mail using a shell script

Using CentOS 7's default mailx (appears as heirloom-mailx), I've simplified this to just using a text file with your required headers and a static boundary for multipart/mixed and multipart/alternative setup.

I'm sure you can figure out multipart/related if you want with the same setup.

test.txt:

--000000000000f3b2150570186a0e
Content-Type: multipart/alternative; boundary="000000000000f3b2130570186a0c"

--000000000000f3b2130570186a0c
Content-Type: text/plain; charset="UTF-8"

This is my plain text stuff here, in case the email client does not support HTML or is blocking it purposely

My Link Here <http://www.example.com>

--000000000000f3b2130570186a0c
Content-Type: text/html; charset="UTF-8"

<div dir="ltr">
<div>This is my HTML version of the email</div>
<div><br></div>
<div><a href="http://www.example.com">My Link Here</a><br></div>
</div>

--000000000000f3b2130570186a0c--
--000000000000f3b2150570186a0e
Content-Type: text/csv; charset="US-ASCII"; name="test.csv"
Content-Disposition: attachment; filename="test.csv"
Content-Transfer-Encoding: base64
X-Attachment-Id: f_jj5qmzqz0

The boundaries define multipart segments.

The boundary ID that has no dashes at the end is a start point of a segment.

The one with the two dashes at the end is the end point.

In this example, there's a subpart within the multipart/mixed main section, for multipart/alternative.

The multipart/alternative method basically says "Fallback to this, IF the priority part does not succeed" - in this example HTML is taken as priority normally by email clients. If an email client won't display the HTML, it falls back to the plain text.

The multipart/mixed method which encapsulates this whole message, is basically saying there's different content here, display both.

In this example, I placed a CSV file attachment on the email. You'll see the attachment get plugged in using base64 in the command below.

I threw in the attachment as an example, you'll have to set your content type appropriately for your attachment and specify whether inline or not.

The X-Attachment-Id is necessary for some providers, randomize the ID you set.

The command to mail this is:

echo -e "`cat test.txt; openssl base64 -e < test.csv`\n--000000000000f3b2150570186a0e--\n" | mailx -s "Test 2 $( echo -e "\nContent-Type: multipart/mixed; boundary=\"000000000000f3b2150570186a0e\"" )" -r [email protected] [email protected]

As you can see in the mailx Subject line I insert the multipart boundary statically, this is the first header the email client will see.

Then comes the test.txt contents being dumped.

Regarding the attachment, I use openssl (which is pretty standard on systems) to convert the file attachment to base64.

Additionally, I added the boundary close statement at the end of this echo, to signify the end of the message.

This works around heirloom-mailx problems and is virtually script-less.

The echo can be a feed instead, or any other number of methods.

Select first and last row from grouped data

Using data.table:

# convert to data.table
setDT(df) 
# order, group, filter
df[order(stopSequence)][, .SD[c(1, .N)], by = id]

   id stopId stopSequence
1:  1      a            1
2:  1      c            3
3:  2      b            1
4:  2      c            4
5:  3      b            1
6:  3      a            3

MySQL JOIN the most recent row only?

SELECT CONCAT(title,' ',forename,' ',surname) AS name * FROM customer c 
INNER JOIN customer_data d on c.id=d.customer_id WHERE name LIKE '%Smith%' 

i think you need to change c.customer_id to c.id

else update table structure

PHP: Return all dates between two dates in an array

I love a solid one-liner!

My php discovery of the day was that array_push() returns the new number of elements in the array.

I managed to check for the end date match, increment $x, and push new elements all within the two-part condition statement of an empty while loop.

function getDatesFromRange($a,$b,$x=0,$dates=[]){
    while(end($dates)!=$b && $x=array_push($dates,date("Y-m-d",strtotime("$a +$x day"))));
    return $dates;
}
var_export(getDatesFromRange('2010-10-01','2010-10-05'));

The most similar function to mine on this page is drolex's (which I didn't actually find until after I wrote mine, if you believe me). I did some speed tests across large and small date ranges and they seem to beat each other just as often -- so I'm calling them equal performers. Here are some other comparisons:

  • We both use date(), strtotime(), and two array functions.
  • Drolex uses just three variables, I use the same three plus $x.
  • Because loading the start date into the $date array is not necessary for my function, I can declare it in the function parameters and spare the line (likewise with $x).

**Just a couple of important notes:

1- Date strings MUST BE validated before being fed to the function.

2- The above function can only handle forward moving date ranges. If you want backward moving date ranges, simply reverse the date order in the function call and add a minus after $x=. (Pretty slick, eh?)

function getDatesFromRange($a,$b,$x=0,$dates=[]){
    while(end($dates)!=$b && $x=-array_push($dates,date("Y-m-d",strtotime("$a +$x day"))));
    return $dates;
}
var_export(getDatesFromRange('2010-10-05','2010-10-01'));

One more extension/consideration...

Imagine you have a multi-cultural (or sloppy) user base, and your function MUST be able to receive start and end dates in different valid formats AND you need to be able to output the array in any of the valid formats? By minor adjustment, I've provided a solution for that.

By "valid" I mean YYYY-MM-DD, MM/DD/YYY, and DD-MM-YYYY, these are massively popular standards world-wide, if another format is necessary then usability would come down to strtotime's comprehension of it.

Here is the Demo.

Code:

function getDatesFromRange($a,$b,$format='Y-m-d',$dates=[],$x=0){
    while(date($format,strtotime(end($dates)))!=date($format,strtotime($b)) && $x=array_push($dates,date($format,strtotime("$a +$x day"))));
    return $dates;
}

$formats=array("Computer"=>'Y-m-d',"American"=>'m/d/Y','Non-American'=>'d-m-Y');
$start='15-02-2017';    // Non-American formatted start date
$end='2017-02-27';  // Computer formatted start date
foreach($formats as $label=>$format){
    echo "<br>$label<br>";
    var_export(getDatesFromRange($start,$end,$format));
    echo "<br>";
}

Output

Computer
array ( 0 => '2017-02-15', 1 => '2017-02-16', 2 => '2017-02-17', 3 => '2017-02-18',
        4 => '2017-02-19', 5 => '2017-02-20', 6 => '2017-02-21', 7 => '2017-02-22',
        8 => '2017-02-23', 9 => '2017-02-24', 10 => '2017-02-25', 11 => '2017-02-26',
        12 => '2017-02-27', )

American
array ( 0 => '02/15/2017', 1 => '02/16/2017', 2 => '02/17/2017', 3 => '02/18/2017',
        4 => '02/19/2017', 5 => '02/20/2017', 6 => '02/21/2017', 7 => '02/22/2017',
        8 => '02/23/2017', 9 => '02/24/2017', 10 => '02/25/2017', 11 => '02/26/2017',
        12 => '02/27/2017', )

Non-American
array ( 0 => '15-02-2017', 1 => '16-02-2017', 2 => '17-02-2017', 3 => '18-02-2017',
        4 => '19-02-2017', 5 => '20-02-2017', 6 => '21-02-2017', 7 => '22-02-2017',
        8 => '23-02-2017', 9 => '24-02-2017', 10 => '25-02-2017', 11 => '26-02-2017',
        12 => '27-02-2017', )

Now some people don't 100% trust strtotime() because of some buggy behaviors. I think I've read that it will foul up when trying to jump a month from a leap-day. However, unless someone can reproduce it to prove me wrong, strtotime() is never going to let you down when you are only incrementing by one day.

Cocoa: What's the difference between the frame and the bounds?

Frame vs bounds

  • If you create a view at X:0, Y:0, width:400, height:400, its frame and bounds are the same.
  • If you move that view to X:400, its frame will reflect that change but its bounds will not. Remember, the bounds is relative to the view’s own space, and internally to the view nothing has changed.
  • If you transform the view, e.g. rotating it or scaling it up, the frame will change to reflect that, but the bounds still won’t – as far as the view is concerned internally, it hasn’t changed.
  • If you change the bounds then it will change the content inside the frame because the origin of the bounds rectangle starts at a different part of the view.

java.util.MissingResourceException: Can't find bundle for base name 'property_file name', locale en_US

You should set property file name without .properties extension, it works correctly for me:)

Oracle client ORA-12541: TNS:no listener

I also faced the same problem but I resolved the issue by starting the TNS listener in control panel -> administrative tools -> services ->oracle TNS listener start.I am using windows Xp and Toad to connect to Oracle.

Call angularjs function using jquery/javascript

Try this:

const scope = angular.element(document.getElementById('YourElementId')).scope();
scope.$apply(function(){
     scope.myfunction('test');
});

How to view DLL functions?

If a DLL is written in one of the .NET languages and if you only want to view what functions, there is a reference to this DLL in the project.

Then doubleclick the DLL in the references folder and then you will see what functions it has in the OBJECT EXPLORER window

If you would like to view the source code of that DLL file you can use a decompiler application such as .NET reflector. hope this helps you.

Changes in import statement python3

Relative import happens whenever you are importing a package relative to the current script/package.

Consider the following tree for example:

mypkg
+-- base.py
+-- derived.py

Now, your derived.py requires something from base.py. In Python 2, you could do it like this (in derived.py):

from base import BaseThing

Python 3 no longer supports that since it's not explicit whether you want the 'relative' or 'absolute' base. In other words, if there was a Python package named base installed in the system, you'd get the wrong one.

Instead it requires you to use explicit imports which explicitly specify location of a module on a path-alike basis. Your derived.py would look like:

from .base import BaseThing

The leading . says 'import base from module directory'; in other words, .base maps to ./base.py.

Similarly, there is .. prefix which goes up the directory hierarchy like ../ (with ..mod mapping to ../mod.py), and then ... which goes two levels up (../../mod.py) and so on.

Please however note that the relative paths listed above were relative to directory where current module (derived.py) resides in, not the current working directory.


@BrenBarn has already explained the star import case. For completeness, I will have to say the same ;).

For example, you need to use a few math functions but you use them only in a single function. In Python 2 you were permitted to be semi-lazy:

def sin_degrees(x):
    from math import *
    return sin(degrees(x))

Note that it already triggers a warning in Python 2:

a.py:1: SyntaxWarning: import * only allowed at module level
  def sin_degrees(x):

In modern Python 2 code you should and in Python 3 you have to do either:

def sin_degrees(x):
    from math import sin, degrees
    return sin(degrees(x))

or:

from math import *

def sin_degrees(x):
    return sin(degrees(x))

Convert all strings in a list to int

I also want to add Python | Converting all strings in list to integers

Method #1 : Naive Method

# Python3 code to demonstrate 
# converting list of strings to int 
# using naive method 

# initializing list 
test_list = ['1', '4', '3', '6', '7'] 

# Printing original list 
print ("Original list is : " + str(test_list)) 

# using naive method to 
# perform conversion 
for i in range(0, len(test_list)): 
    test_list[i] = int(test_list[i]) 
    

# Printing modified list 
print ("Modified list is : " + str(test_list)) 

Output:

Original list is : ['1', '4', '3', '6', '7']
Modified list is : [1, 4, 3, 6, 7]

Method #2 : Using list comprehension

# Python3 code to demonstrate 
# converting list of strings to int 
# using list comprehension 

# initializing list 
test_list = ['1', '4', '3', '6', '7'] 

# Printing original list 
print ("Original list is : " + str(test_list)) 

# using list comprehension to 
# perform conversion 
test_list = [int(i) for i in test_list] 
    

# Printing modified list 
print ("Modified list is : " + str(test_list)) 

Output:

Original list is : ['1', '4', '3', '6', '7']
Modified list is : [1, 4, 3, 6, 7]

Method #3 : Using map()

# Python3 code to demonstrate 
# converting list of strings to int 
# using map() 

# initializing list 
test_list = ['1', '4', '3', '6', '7'] 

# Printing original list 
print ("Original list is : " + str(test_list)) 

# using map() to 
# perform conversion 
test_list = list(map(int, test_list)) 
    

# Printing modified list 
print ("Modified list is : " + str(test_list)) 

Output:

Original list is : ['1', '4', '3', '6', '7']
Modified list is : [1, 4, 3, 6, 7]

Nesting queries in SQL

The way I see it, the only place for a nested query would be in the WHERE clause, so e.g.

SELECT country.name, country.headofstate
FROM country 
WHERE country.headofstate LIKE 'A%' AND 
country.id in (SELECT country_id FROM city WHERE population > 100000)

Apart from that, I have to agree with Adrian on: why the heck should you use nested queries?

django MultiValueDictKeyError error, how do I deal with it

Choose what is best for you:

1

is_private = request.POST.get('is_private', False);

If is_private key is present in request.POST the is_private variable will be equal to it, if not, then it will be equal to False.

2

if 'is_private' in request.POST:
    is_private = request.POST['is_private']
else:
    is_private = False

3

from django.utils.datastructures import MultiValueDictKeyError
try:
    is_private = request.POST['is_private']
except MultiValueDictKeyError:
    is_private = False

fastest way to export blobs from table into individual files

I tried using a CLR function and it was more than twice as fast as BCP. Here's my code.

Original Method:

SET @bcpCommand = 'bcp "SELECT blobcolumn FROM blobtable WHERE ID = ' + CAST(@FileID AS VARCHAR(20)) + '" queryout "' + @FileName + '" -T -c'
EXEC master..xp_cmdshell @bcpCommand

CLR Method:

declare @file varbinary(max) = (select blobcolumn from blobtable WHERE ID = @fileid)
declare @filepath nvarchar(4000) = N'c:\temp\' + @FileName
SELECT Master.dbo.WriteToFile(@file, @filepath, 0)

C# Code for the CLR function

using System;
using System.Data;
using System.Data.SqlTypes;
using System.IO;
using Microsoft.SqlServer.Server;

namespace BlobExport
{
    public class Functions
    {
      [SqlFunction]
      public static SqlString WriteToFile(SqlBytes binary, SqlString path, SqlBoolean append)
      {        
        try
        {
          if (!binary.IsNull && !path.IsNull && !append.IsNull)
          {         
            var dir = Path.GetDirectoryName(path.Value);           
            if (!Directory.Exists(dir))              
              Directory.CreateDirectory(dir);            
              using (var fs = new FileStream(path.Value, append ? FileMode.Append : FileMode.OpenOrCreate))
            {
                byte[] byteArr = binary.Value;
                for (int i = 0; i < byteArr.Length; i++)
                {
                    fs.WriteByte(byteArr[i]);
                };
            }
            return "SUCCESS";
          }
          else
             "NULL INPUT";
        }
        catch (Exception ex)
        {          
          return ex.Message;
        }
      }
    }
}

get the titles of all open windows

Based on the previous answer that give me some errors, finaly I use this code with GetOpenedWindows function:

public class InfoWindow
{
            public IntPtr Handle = IntPtr.Zero;
            public FileInfo File = new FileInfo( Application.ExecutablePath );
            public string Title = Application.ProductName;
            public override string ToString() {
                return  File.Name + "\t>\t" + Title;
            }
 }//CLASS

/// <summary>Contains functionality to get info on the open windows.</summary>
public static class RuningWindows
{   
            internal static event EventHandler WindowActivatedChanged;    
            internal static Timer TimerWatcher = new Timer();    
            internal static InfoWindow WindowActive = new InfoWindow();       
            internal static void DoStartWatcher() {
                TimerWatcher.Interval = 500;
                TimerWatcher.Tick += TimerWatcher_Tick;
                TimerWatcher.Start();    
            }                    

            /// <summary>Returns a dictionary that contains the handle and title of all the open windows.</summary>
            /// <returns>A dictionary that contains the handle and title of all the open windows.</returns>
            public static IDictionary<IntPtr , InfoWindow> GetOpenedWindows()
            {
                IntPtr shellWindow = GetShellWindow();
                Dictionary<IntPtr , InfoWindow> windows = new Dictionary<IntPtr , InfoWindow>();

                EnumWindows( new EnumWindowsProc( delegate( IntPtr hWnd , int lParam ) {
                    if ( hWnd == shellWindow ) return true;
                    if ( !IsWindowVisible( hWnd ) ) return true;    
                    int length = GetWindowTextLength( hWnd );
                    if ( length == 0 ) return true;    
                    StringBuilder builder = new StringBuilder( length );
                    GetWindowText( hWnd , builder , length + 1 );    
                    var info = new InfoWindow();
                    info.Handle = hWnd;
                    info.File = new FileInfo( GetProcessPath( hWnd ) );
                    info.Title = builder.ToString();    
                    windows[hWnd] = info;
                    return true;    
                } ) , 0 );    
                return windows;
            }

            private delegate bool EnumWindowsProc( IntPtr hWnd , int lParam );  

            public static string GetProcessPath( IntPtr hwnd )
            {
                uint pid = 0;
                GetWindowThreadProcessId( hwnd , out pid );
                if ( hwnd != IntPtr.Zero ) {
                    if ( pid != 0 ) {
                        var process = Process.GetProcessById( (int) pid );
                        if ( process != null ) {
                            return process.MainModule.FileName.ToString();
                        }
                    }
                }
                return "";
            }    

            [DllImport( "USER32.DLL" )]
            private static extern bool EnumWindows( EnumWindowsProc enumFunc , int lParam );

            [DllImport( "USER32.DLL" )]
            private static extern int GetWindowText( IntPtr hWnd , StringBuilder lpString , int nMaxCount );

            [DllImport( "USER32.DLL" )]
            private static extern int GetWindowTextLength( IntPtr hWnd );

            [DllImport( "USER32.DLL" )]
            private static extern bool IsWindowVisible( IntPtr hWnd );

            [DllImport( "USER32.DLL" )]
            private static extern IntPtr GetShellWindow();

            [DllImport( "user32.dll" )]
            private static extern IntPtr GetForegroundWindow();

            //WARN: Only for "Any CPU":
            [DllImport( "user32.dll" , CharSet = CharSet.Auto , SetLastError = true )]
            private static extern int GetWindowThreadProcessId( IntPtr handle , out uint processId );    


            static void TimerWatcher_Tick( object sender , EventArgs e )
            {
                var windowActive = new InfoWindow();
                windowActive.Handle = GetForegroundWindow();
                string path = GetProcessPath( windowActive.Handle );
                if ( string.IsNullOrEmpty( path ) ) return;
                windowActive.File = new FileInfo( path );
                int length = GetWindowTextLength( windowActive.Handle );
                if ( length == 0 ) return;
                StringBuilder builder = new StringBuilder( length );
                GetWindowText( windowActive.Handle , builder , length + 1 );
                windowActive.Title = builder.ToString();
                if ( windowActive.ToString() != WindowActive.ToString() ) {
                    //fire:
                    WindowActive = windowActive;
                    if ( WindowActivatedChanged != null ) WindowActivatedChanged( sender , e );
                    Console.WriteLine( "Window: " + WindowActive.ToString() );
                }
            }

}//CLASS

Warning: You can only compil/debug under "Any CPU" to access to 32bits Apps...

Changing text color of menu item in navigation drawer

I used below code to change Navigation drawer text color in my app.

NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setItemTextColor(ColorStateList.valueOf(Color.WHITE));

How to run a .awk file?

If you put #!/bin/awk -f on the first line of your AWK script it is easier. Plus editors like Vim and ... will recognize the file as an AWK script and you can colorize. :)

#!/bin/awk -f
BEGIN {}  # Begin section
{}        # Loop section
END{}     # End section

Change the file to be executable by running:

chmod ugo+x ./awk-script

and you can then call your AWK script like this:

`$ echo "something" | ./awk-script`

NSInternalInconsistencyException', reason: 'Could not load NIB in bundle: 'NSBundle

While developing the ios app i too face similar kind of issue. Simple Restart of the xcode works for me. Hope this will help some one.

How can I delete (not disable) ActiveX add-ons in Internet Explorer (7 and 8 Beta 2)?

You can go to IE Tools -> Internet options -> Advanced Tab. Under Advanced, check for security and put a check on the 1st 2 options which says,"Allow active content from CDs to run on My Computer* and Allow active content to run in files on My Computer*"

Restart your browser and the ActiveX scripts will not be shown.

How to add checkboxes to JTABLE swing

1) JTable knows JCheckbox with built-in Boolean TableCellRenderers and TableCellEditor by default, then there is contraproductive declare something about that,

2) AbstractTableModel should be useful, where is in the JTable required to reduce/restrict/change nested and inherits methods by default implemented in the DefaultTableModel,

3) consider using DefaultTableModel, (if you are not sure about how to works) instead of AbstractTableModel,

table_with_BooleanType_column

could be generated from simple code:

import javax.swing.*;
import javax.swing.table.*;

public class TableCheckBox extends JFrame {

    private static final long serialVersionUID = 1L;
    private JTable table;

    public TableCheckBox() {
        Object[] columnNames = {"Type", "Company", "Shares", "Price", "Boolean"};
        Object[][] data = {
            {"Buy", "IBM", new Integer(1000), new Double(80.50), false},
            {"Sell", "MicroSoft", new Integer(2000), new Double(6.25), true},
            {"Sell", "Apple", new Integer(3000), new Double(7.35), true},
            {"Buy", "Nortel", new Integer(4000), new Double(20.00), false}
        };
        DefaultTableModel model = new DefaultTableModel(data, columnNames);
        table = new JTable(model) {

            private static final long serialVersionUID = 1L;

            /*@Override
            public Class getColumnClass(int column) {
            return getValueAt(0, column).getClass();
            }*/
            @Override
            public Class getColumnClass(int column) {
                switch (column) {
                    case 0:
                        return String.class;
                    case 1:
                        return String.class;
                    case 2:
                        return Integer.class;
                    case 3:
                        return Double.class;
                    default:
                        return Boolean.class;
                }
            }
        };
        table.setPreferredScrollableViewportSize(table.getPreferredSize());
        JScrollPane scrollPane = new JScrollPane(table);
        getContentPane().add(scrollPane);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                TableCheckBox frame = new TableCheckBox();
                frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
                frame.pack();
                frame.setLocation(150, 150);
                frame.setVisible(true);
            }
        });
    }
}

SQL Server: Examples of PIVOTing String data

With pivot_data as
(
select 
action, -- grouping column
view_edit -- spreading column
from tbl
)
select action, [view], [edit]
from   pivot_data
pivot  ( max(view_edit) for view_edit in ([view], [edit]) ) as p;

How Can I Set the Default Value of a Timestamp Column to the Current Timestamp with Laravel Migrations?

In laravel 7, to set current time use following:

$table->timestamp('column_name')->useCurrent();

How to delete an app from iTunesConnect / App Store Connect

Easy.

(as of 2021)

Click your app, click App Information in the left side menu, scroll all the way down to the Additional Information section, click Remove App.

Boom. done.

How to check if an alert exists using WebDriver?

I found catching exception of driver.switchTo().alert(); is so slow in Firefox (FF V20 & selenium-java-2.32.0).`

So I choose another way:

    private static boolean isDialogPresent(WebDriver driver) {
        try {
            driver.getTitle();
            return false;
        } catch (UnhandledAlertException e) {
            // Modal dialog showed
            return true;
        }
    }

And it's a better way when most of your test cases is NO dialog present (throwing exception is expensive).

What is best tool to compare two SQL Server databases (schema and data)?

Database Workbench can made it too

http://www.upscene.com/products.dbw.index.php

Cross database development

Use the Schema Compare and Migration Tools to compare testing and deployed databases, migrate existing databases to different database systems.

you can also made it with database Comparer

http://www.clevercomponents.com/products/dbcomparer/dbcomparer.asp

I use it for Firebird and it works well.

How to select records without duplicate on just one field in SQL?

Try this one

SELECT country_id, country_title 
FROM (SELECT country_id, country_title,
CASE
WHEN country_title=LAG(country_title, 1, 0) OVER(ORDER BY country_title) THEN 1
ELSE 0
END AS "Duplicates"
FROM tbl_countries)
WHERE "Duplicates"=0;

Copy and Paste a set range in the next empty row

You could also try this

Private Sub CommandButton1_Click()

Sheets("Sheet1").Range("A3:E3").Copy

Dim lastrow As Long
lastrow = Range("A65536").End(xlUp).Row

Sheets("Summary Info").Activate
Cells(lastrow + 1, 1).PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks:=False, Transpose:=False

End Sub

Which Python memory profiler is recommended?

I recommend Dowser. It is very easy to setup, and you need zero changes to your code. You can view counts of objects of each type through time, view list of live objects, view references to live objects, all from the simple web interface.

# memdebug.py

import cherrypy
import dowser

def start(port):
    cherrypy.tree.mount(dowser.Root())
    cherrypy.config.update({
        'environment': 'embedded',
        'server.socket_port': port
    })
    cherrypy.server.quickstart()
    cherrypy.engine.start(blocking=False)

You import memdebug, and call memdebug.start. That's all.

I haven't tried PySizer or Heapy. I would appreciate others' reviews.

UPDATE

The above code is for CherryPy 2.X, CherryPy 3.X the server.quickstart method has been removed and engine.start does not take the blocking flag. So if you are using CherryPy 3.X

# memdebug.py

import cherrypy
import dowser

def start(port):
    cherrypy.tree.mount(dowser.Root())
    cherrypy.config.update({
        'environment': 'embedded',
        'server.socket_port': port
    })
    cherrypy.engine.start()

MySQL does not start when upgrading OSX to Yosemite or El Capitan

I’ve got a similar problem with MySQL on a Mac (Mac Os X Could not startup MySQL Server. Reason: 255 and also “ERROR! The server quit without updating PID file”). After a long trial and error process, finally in order to restore the file permissions, I’ve just do that:

* launch the Disk Utilities.app
* choose my drive on the left panel
* click on the “Repair disk permissions” button

This did the trick for me.

Hoping this can help someone else.

database vs. flat files

  1. Databases can handle querying tasks, so you don't have to walk over files manually. Databases can handle very complicated queries.
  2. Databases can handle indexing tasks, so if tasks like get record with id = x can be VERY fast
  3. Databases can handle multiprocess/multithreaded access.
  4. Databases can handle access from network
  5. Databases can watch for data integrity
  6. Databases can update data easily (see 1) )
  7. Databases are reliable
  8. Databases can handle transactions and concurrent access
  9. Databases + ORMs let you manipulate data in very programmer friendly way.

How to set a session variable when clicking a <a> link

Is your link to another web page? If so, perhaps you could put the variable in the query string and set the session variable when the page being linked to is loaded.

So the link looks like this:

<a href="home.php?variable=value" name="home">home</a>

And the homge page would parse the query string and set the session variable.

How to reset selected file with input tag file type in Angular 2?

Short version Plunker:

import { Component } from '@angular/core';

@Component({
  selector: 'my-app',
  template: `
      <input #myInput type="file" placeholder="File Name" name="filename">
      <button (click)="myInput.value = ''">Reset</button>
  `
})
export class AppComponent {


}

And i think more common case is to not using button but do reset automatically. Angular Template statements support chaining expressions so Plunker:

import { Component } from '@angular/core';

@Component({
  selector: 'my-app',
  template: `
      <input #myInput type="file" (change)="onChange(myInput.value, $event); myInput.value = ''" placeholder="File Name" name="filename">
  `
})
export class AppComponent {

  onChange(files, event) {
    alert( files );
    alert( event.target.files[0].name );
  }

}

And interesting link about why there is no recursion on value change.

Google Maps: Auto close open InfoWindows?

//assuming you have a map called 'map'
var infowindow = new google.maps.InfoWindow();

var latlng1 = new google.maps.LatLng(0,0);
var marker1 = new google.maps.Marker({position:latlng1, map:map});
google.maps.event.addListener(marker1, 'click',
    function(){
        infowindow.close();//hide the infowindow
        infowindow.setContent('Marker #1');//update the content for this marker
        infowindow.open(map, marker1);//"move" the info window to the clicked marker and open it
    }
);
var latlng2 = new google.maps.LatLng(10,10);
var marker2 = new google.maps.Marker({position:latlng2, map:map});
google.maps.event.addListener(marker2, 'click',
    function(){
        infowindow.close();//hide the infowindow
        infowindow.setContent('Marker #2');//update the content for this marker
        infowindow.open(map, marker2);//"move" the info window to the clicked marker and open it
    }
);

This will "move" the info window around to each clicked marker, in effect closing itself, then reopening (and panning to fit the viewport) in its new location. It changes its contents before opening to give the desired effect. Works for n markers.

How to pass parameters to a Script tag?

It's better to Use feature in html5 5 data Attributes

<script src="http://path.to/widget.js" data-width="200" data-height="200">
</script>

Inside the script file http://path.to/widget.js you can get the paremeters in that way:

<script>
function getSyncScriptParams() {
         var scripts = document.getElementsByTagName('script');
         var lastScript = scripts[scripts.length-1];
         var scriptName = lastScript;
         return {
             width : scriptName.getAttribute('data-width'),
             height : scriptName.getAttribute('data-height')
         };
 }
</script>

How can I tell what edition of SQL Server runs on the machine?

You can get just the edition name by using the following steps.

  • Open "SQL Server Configuration Manager"
  • From the List of SQL Server Services, Right Click on "SQL Server (Instance_name)" and Select Properties.
  • Select "Advanced" Tab from the Properties window.
  • Verify Edition Name from the "Stock Keeping Unit Name"
  • Verify Edition Id from the "Stock Keeping Unit Id"
  • Verify Service Pack from the "Service Pack Level"
  • Verify Version from the "Version"

screen shot

gradlew: Permission Denied

This error is gradle permission related . Just paste below line in your terminal and run...

chmod a+rx android/gradlew

char initial value in Java

Typically for local variables I initialize them as late as I can. It's rare that I need a "dummy" value. However, if you do, you can use any value you like - it won't make any difference, if you're sure you're going to assign a value before reading it.

If you want the char equivalent of 0, it's just Unicode 0, which can be written as

char c = '\0';

That's also the default value for an instance (or static) variable of type char.

Best way to "negate" an instanceof

If you find it more understandable, you can do something like this with Java 8 :

public static final Predicate<Object> isInstanceOfTheClass = 
    objectToTest -> objectToTest instanceof TheClass;

public static final Predicate<Object> isNotInstanceOfTheClass = 
    isInstanceOfTheClass.negate(); // or objectToTest -> !(objectToTest instanceof TheClass)

if (isNotInstanceOfTheClass.test(myObject)) {
    // do something
}

How to find the operating system version using JavaScript?

JavaScript have access to the window.navigator.platform - a string representing the platform of the browser: https://developer.mozilla.org/en-US/docs/Web/API/NavigatorID/platform

Use it to extract whatever details you need (and can). Note that there are no guarantees that the client actually uses that platform since this can easily be modified in many ways.

Gunicorn worker timeout error

Could it be this? http://docs.gunicorn.org/en/latest/settings.html#timeout

Other possibilities could be your response is taking too long or is stuck waiting.

How to run .jar file by double click on Windows 7 64-bit?

Your problem might also be inside your Java code setting, I mean, if your program somehow could not realize the main class/main file (entry point), it will not launch the the program/.jar (specially application built on IDE's). To solve that on an IDE :

  • Right Click the project > Properties > Run > Browse Main Class > OK.
  • Clean and Rebuild

Try running it now. Hope it helps

Creating columns in listView and add items

Your first problem is that you are passing -3 to the 2nd parameter of Columns.Add. It needs to be -2 for it to auto-size the column. Source: http://msdn.microsoft.com/en-us/library/system.windows.forms.listview.columns.aspx (look at the comments on the code example at the bottom)

private void initListView()
{
    // Add columns
    lvRegAnimals.Columns.Add("Id", -2,HorizontalAlignment.Left);
    lvRegAnimals.Columns.Add("Name", -2, HorizontalAlignment.Left);
    lvRegAnimals.Columns.Add("Age", -2, HorizontalAlignment.Left);
}

You can also use the other overload, Add(string). E.g:

lvRegAnimals.Columns.Add("Id");
lvRegAnimals.Columns.Add("Name");
lvRegAnimals.Columns.Add("Age");

Reference for more overloads: http://msdn.microsoft.com/en-us/library/system.windows.forms.listview.columnheadercollection.aspx

Second, to add items to the ListView, you need to create instances of ListViewItem and add them to the listView's Items collection. You will need to use the string[] constructor.

var item1 = new ListViewItem(new[] {"id123", "Tom", "24"});
var item2 = new ListViewItem(new[] {person.Id, person.Name, person.Age});
lvRegAnimals.Items.Add(item1);
lvRegAnimals.Items.Add(item2);

You can also store objects in the item's Tag property.

item2.Tag = person;

And then you can extract it

var person = item2.Tag as Person;

Let me know if you have any questions and I hope this helps!

Importing images from a directory (Python) to list or dictionary

from PIL import Image
import os, os.path

imgs = []
path = "/home/tony/pictures"
valid_images = [".jpg",".gif",".png",".tga"]
for f in os.listdir(path):
    ext = os.path.splitext(f)[1]
    if ext.lower() not in valid_images:
        continue
    imgs.append(Image.open(os.path.join(path,f)))
   

How to initialize weights in PyTorch?

Here is the better way, just pass your whole model

import torch.nn as nn
def initialize_weights(model):
    # Initializes weights according to the DCGAN paper
    for m in model.modules():
        if isinstance(m, (nn.Conv2d, nn.ConvTranspose2d, nn.BatchNorm2d)):
            nn.init.normal_(m.weight.data, 0.0, 0.02)
        # if you also want for linear layers ,add one more elif condition 

Oracle row count of table by count(*) vs NUM_ROWS from DBA_TABLES

According to the documentation NUM_ROWS is the "Number of rows in the table", so I can see how this might be confusing. There, however, is a major difference between these two methods.

This query selects the number of rows in MY_TABLE from a system view. This is data that Oracle has previously collected and stored.

select num_rows from all_tables where table_name = 'MY_TABLE'

This query counts the current number of rows in MY_TABLE

select count(*) from my_table

By definition they are difference pieces of data. There are two additional pieces of information you need about NUM_ROWS.

  1. In the documentation there's an asterisk by the column name, which leads to this note:

    Columns marked with an asterisk (*) are populated only if you collect statistics on the table with the ANALYZE statement or the DBMS_STATS package.

    This means that unless you have gathered statistics on the table then this column will not have any data.

  2. Statistics gathered in 11g+ with the default estimate_percent, or with a 100% estimate, will return an accurate number for that point in time. But statistics gathered before 11g, or with a custom estimate_percent less than 100%, uses dynamic sampling and may be incorrect. If you gather 99.999% a single row may be missed, which in turn means that the answer you get is incorrect.

If your table is never updated then it is certainly possible to use ALL_TABLES.NUM_ROWS to find out the number of rows in a table. However, and it's a big however, if any process inserts or deletes rows from your table it will be at best a good approximation and depending on whether your database gathers statistics automatically could be horribly wrong.

Generally speaking, it is always better to actually count the number of rows in the table rather then relying on the system tables.

How to use nan and inf in C?

<inf.h>

/* IEEE positive infinity.  */

#if __GNUC_PREREQ(3,3)
# define INFINITY   (__builtin_inff())
#else
# define INFINITY   HUGE_VALF
#endif

and

<bits/nan.h>
#ifndef _MATH_H
# error "Never use <bits/nan.h> directly; include <math.h> instead."
#endif


/* IEEE Not A Number.  */

#if __GNUC_PREREQ(3,3)

# define NAN    (__builtin_nanf (""))

#elif defined __GNUC__

# define NAN \
  (__extension__                                  \
   ((union { unsigned __l __attribute__ ((__mode__ (__SI__))); float __d; })  \
    { __l: 0x7fc00000UL }).__d)

#else

# include <endian.h>

# if __BYTE_ORDER == __BIG_ENDIAN
#  define __nan_bytes       { 0x7f, 0xc0, 0, 0 }
# endif
# if __BYTE_ORDER == __LITTLE_ENDIAN
#  define __nan_bytes       { 0, 0, 0xc0, 0x7f }
# endif

static union { unsigned char __c[4]; float __d; } __nan_union
    __attribute_used__ = { __nan_bytes };
# define NAN    (__nan_union.__d)

#endif  /* GCC.  */

What's the difference between setWebViewClient vs. setWebChromeClient?

If you want to log errors from web-page, you should use WebChromeClient and override its onConsoleMessage:

webView.settings.apply {
    javaScriptEnabled = true
    javaScriptCanOpenWindowsAutomatically = true
    domStorageEnabled = true
}
webView.webViewClient = WebViewClient()
webView.webChromeClient = MyWebChromeClient()

private class MyWebChromeClient : WebChromeClient() {
    override fun onConsoleMessage(consoleMessage: ConsoleMessage): Boolean {
        Timber.d("${consoleMessage.message()}")
        Timber.d("${consoleMessage.lineNumber()} ${consoleMessage.sourceId()}")
        return super.onConsoleMessage(consoleMessage)
    }
}

Why are C# 4 optional parameters defined on interface not enforced on implementing class?

UPDATE: This question was the subject of my blog on May 12th 2011. Thanks for the great question!

Suppose you have an interface as you describe, and a hundred classes that implement it. Then you decide to make one of the parameters of one of the interface's methods optional. Are you suggesting that the right thing to do is for the compiler to force the developer to find every implementation of that interface method, and make the parameter optional as well?

Suppose we did that. Now suppose the developer did not have the source code for the implementation:


// in metadata:
public class B 
{ 
    public void TestMethod(bool b) {}
}

// in source code
interface MyInterface 
{ 
    void TestMethod(bool b = false); 
}
class D : B, MyInterface {}
// Legal because D's base class has a public method 
// that implements the interface method

How is the author of D supposed to make this work? Are they required in your world to call up the author of B on the phone and ask them to please ship them a new version of B that makes the method have an optional parameter?

That's not going to fly. What if two people call up the author of B, and one of them wants the default to be true and one of them wants it to be false? What if the author of B simply refuses to play along?

Perhaps in that case they would be required to say:

class D : B, MyInterface 
{
    public new void TestMethod(bool b = false)
    {
        base.TestMethod(b);
    }
}

The proposed feature seems to add a lot of inconvenience for the programmer with no corresponding increase in representative power. What's the compelling benefit of this feature which justifies the increased cost to the user?


UPDATE: In the comments below, supercat suggests a language feature that would genuinely add power to the language and enable some scenarios similar to the one described in this question. FYI, that feature -- default implementations of methods in interfaces -- will be added to C# 8.

How to read and write excel file

String path="C:\\Book2.xlsx";
try {

        File f = new File( path );
        Workbook wb = WorkbookFactory.create(f);
        Sheet mySheet = wb.getSheetAt(0);
        Iterator<Row> rowIter = mySheet.rowIterator();
        for ( Iterator<Row> rowIterator = mySheet.rowIterator() ;rowIterator.hasNext(); )
        {
            for (  Iterator<Cell> cellIterator = ((Row)rowIterator.next()).cellIterator() ; cellIterator.hasNext() ;  ) 
            {
                System.out.println ( ( (Cell)cellIterator.next() ).toString() );
            }
            System.out.println( " **************************************************************** ");
        }
    } catch ( Exception e )
    {
        System.out.println( "exception" );
        e.printStackTrace();
    }

and make sure to have added the jars poi and poi-ooxml (org.apache.poi) to your project

CMD (command prompt) can't go to the desktop

You need to use the change directory command 'cd' to change directory

cd C:\Users\MyName\Desktop

you can use cd \d to change the drive as well.

link for additional resources http://ss64.com/nt/cd.html

multiple conditions for filter in spark data frames

df2 = df1.filter("Status=2")
     .filter("Status=3");

allowing only alphabets in text box using java script

just use onkeypress event like below:

<input type="text" name="onlyalphabet" onkeypress="return (event.charCode > 64 && event.charCode < 91) || (event.charCode > 96 && event.charCode < 123)">

If else on WHERE clause

Note the following is functionally different to Gordon Linoff's answer. His answer assumes that you want to use email2 if email is NULL. Mine assumes you want to use email2 if email is an empty-string. The correct answer will depend on your database (or you could perform a NULL check and an empty-string check - it all depends on what is appropriate for your database design).

SELECT  `id` ,  `naam` 
FROM  `klanten` 
WHERE `email` LIKE  '%[email protected]%'
OR (LENGTH(email) = 0 AND `email2` LIKE  '%[email protected]%')

dictionary update sequence element #0 has length 3; 2 is required

This error raised up because you trying to update dict object by using a wrong sequence (list or tuple) structure.

cash_id.create(cr, uid, lines,context=None) trying to convert lines into dict object:

(0, 0, {
    'name': l.name,
    'date': l.date,
    'amount': l.amount,
    'type': l.type,
    'statement_id': exp.statement_id.id,
    'account_id': l.account_id.id,
    'account_analytic_id': l.analytic_account_id.id,
    'ref': l.ref,
    'note': l.note,
    'company_id': l.company_id.id
})

Remove the second zero from this tuple to properly convert it into a dict object.

To test it your self, try this into python shell:

>>> l=[(0,0,{'h':88})]
>>> a={}
>>> a.update(l)

Traceback (most recent call last):
  File "<pyshell#11>", line 1, in <module>
    a.update(l)
ValueError: dictionary update sequence element #0 has length 3; 2 is required

>>> l=[(0,{'h':88})]
>>> a.update(l)

Equivalent to AssemblyInfo in dotnet core/csproj

Adding to NightOwl888's answer, you can go one step further and add an AssemblyInfo class rather than just a plain class:

enter image description here

Range of values in C Int and Long 32 - 64 bits

In C and C++ memory requirements of some variable :

signed char: -2^07 to +2^07-1
short: -2^15 to +2^15-1
int: -2^15 to +2^15-1
long: -2^31 to +2^31-1
long long: -2^63 to +2^63-1

signed char: -2^07 to +2^07-1
short: -2^15 to +2^15-1
int: -2^31 to +2^31-1
long: -2^31 to +2^31-1
long long: -2^63 to +2^63-1

depends on compiler and architecture of hardware

The international standard for the C language requires only that the size of short variables should be less than or equal to the size of type int, which in turn should be less than or equal to the size of type long.

How to use the unsigned Integer in Java 8 and Java 9?

If using a third party library is an option, there is jOOU (a spin off library from jOOQ), which offers wrapper types for unsigned integer numbers in Java. That's not exactly the same thing as having primitive type (and thus byte code) support for unsigned types, but perhaps it's still good enough for your use-case.

import static org.joou.Unsigned.*;

// and then...
UByte    b = ubyte(1);
UShort   s = ushort(1);
UInteger i = uint(1);
ULong    l = ulong(1);

All of these types extend java.lang.Number and can be converted into higher-order primitive types and BigInteger.

(Disclaimer: I work for the company behind these libraries)

how to get data from selected row from datagridview

I was having the same issue and this works excellently.

Private Sub DataGridView17_CellFormatting(sender As Object, e As System.Windows.Forms.DataGridViewCellFormattingEventArgs) Handles DataGridView17.CellFormatting  
  'Display complete contents in tooltip even though column display cuts off part of it.   
  DataGridView17.Rows(e.RowIndex).Cells(e.ColumnIndex).ToolTipText = DataGridView17.Rows(e.RowIndex).Cells(e.ColumnIndex).Value 
End Sub

Spring RequestMapping for controllers that produce and consume JSON

You shouldn't need to configure the consumes or produces attribute at all. Spring will automatically serve JSON based on the following factors.

  • The accepts header of the request is application/json
  • @ResponseBody annotated method
  • Jackson library on classpath

You should also follow Wim's suggestion and define your controller with the @RestController annotation. This will save you from annotating each request method with @ResponseBody

Another benefit of this approach would be if a client wants XML instead of JSON, they would get it. They would just need to specify xml in the accepts header.

Why is JsonRequestBehavior needed?

MVC defaults to DenyGet to protect you against a very specific attack involving JSON requests to improve the liklihood that the implications of allowing HTTP GET exposure are considered in advance of allowing them to occur.

This is opposed to afterwards when it might be too late.

Note: If your action method does not return sensitive data, then it should be safe to allow the get.

Further reading from my Wrox ASP.NET MVC3 book

By default, the ASP.NET MVC framework does not allow you to respond to an HTTP GET request with a JSON payload. If you need to send JSON in response to a GET, you'll need to explicitly allow the behavior by using JsonRequestBehavior.AllowGet as the second parameter to the Json method. However, there is a chance a malicious user can gain access to the JSON payload through a process known as JSON Hijacking. You do not want to return sensitive information using JSON in a GET request. For more details, see Phil's post at http://haacked.com/archive/2009/06/24/json-hijacking.aspx/ or this SO post.

Haack, Phil (2011). Professional ASP.NET MVC 3 (Wrox Programmer to Programmer) (Kindle Locations 6014-6020). Wrox. Kindle Edition.

Related StackOverflow question

With most recents browsers (starting with Firefox 21, Chrome 27, or IE 10), this is no more a vulnerability.

Error: vector does not name a type

You forgot to add std:: namespace prefix to vector class name.

SSL received a record that exceeded the maximum permissible length. (Error code: ssl_error_rx_record_too_long)

My case is related to Greg B's -- Visual Studio creates two sites when SSL is enabled -- one for secure, and one for normal http requests. However Visual Studio chooses two ports at random, and depending on how you start the debugger you might be pointing towards the wrong page for the request type. Especially if you edit the URL but don't change the port number.

Seeing these posts jogged my memory.

I know this isn't APACHE related, but it is definitely a page that people with that error will find..

ASP.NET Core configuration for .NET Core console application

If you use .netcore 3.1 the simplest way use new configuration system to call CreateDefaultBuilder method of static class Host and configure application

public class Program
{
    public static void Main(string[] args)
    {
        Host.CreateDefaultBuilder(args)
            .ConfigureAppConfiguration((context, config) =>
            {
                IHostEnvironment env = context.HostingEnvironment;
                config.AddEnvironmentVariables()
                    // copy configuration files to output directory
                    .AddJsonFile("appsettings.json")
                    // default prefix for environment variables is DOTNET_
                    .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
                    .AddCommandLine(args);
            })
            .ConfigureServices(services =>
            {
                services.AddSingleton<IHostedService, MySimpleService>();
            })
            .Build()
            .Run();
    }
}

class MySimpleService : IHostedService
{
    public Task StartAsync(CancellationToken cancellationToken)
    {
        Console.WriteLine("StartAsync");
        return Task.CompletedTask;
    }

    public Task StopAsync(CancellationToken cancellationToken)
    {
        Console.WriteLine("StopAsync");
        return Task.CompletedTask;
    }
}

You need set Copy to Output Directory = 'Copy if newer' for the files appsettings.json and appsettings.{environment}.json Also you can set environment variable {prefix}ENVIRONMENT (default prefix is DOTNET) to allow choose specific configuration parameters.

.csproj file:

<PropertyGroup>
  <OutputType>Exe</OutputType>
  <TargetFramework>netcoreapp3.1</TargetFramework>
  <RootNamespace>ConsoleApplication3</RootNamespace>
  <AssemblyName>ConsoleApplication3</AssemblyName>
</PropertyGroup>

<ItemGroup>
  <PackageReference Include="Microsoft.Extensions.Configuration" Version="3.1.7" />
  <PackageReference Include="Microsoft.Extensions.Hosting" Version="3.1.7" />
</ItemGroup>

<ItemGroup>
  <None Update="appsettings.Development.json">
    <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
  </None>
  <None Update="appsettings.json">
    <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
  </None>
</ItemGroup>

more details .NET Generic Host

Static variables in JavaScript

So what I see with the other answers is that they don't address the fundamental architectural requirement of a static attribute in object oriented programming.

Object oriented programming actually has two different styles one is 'class based' (C++, C#, Java etc), the other is 'prototypal' (Javascript). In class based languages a 'static attribute' is supposed to be associated with the class and not the instantiated objects. This concept actually works much more intuitively in a prototypal languages like Javascript because you just assign the attribute as a value of the parent prototype like so.

function MyObject() {};
MyObject.prototype.staticAttribute = "some value";

And access it from every one of the objects that is instantiated from this constructor like so...

var childObject1 = new MyObject(); // Instantiate a child object
var childObject2 = new MyObject(); // Instantiate another child object
console.log(childObject.staticAttribute); // Access the static Attribute from child 1
console.log(childObject.staticAttribute); // Access the static Attribute from child 2

Now if you go ahead and change the MyObject.prototype.staticAttribute the change will cascade down to the child objects that immediately inherit it.

However there are a few 'gotchas' that could significantly undermine the 'static' nature of this attribute, or just leave security vulnerability...

First make sure to hide the constructor from the Global namespace by enclosing it inside another function like the jQuery ready method

 $(document).ready(function () {
    function MyObject() {
        // some constructor instructions
    };
    MyObject.prototype.staticAttribute = "some value";
    var childObject = new MyObject(); // instantiate child object
    console.log(childObject.staticAttribute); // test attribute
});

Second and lastly, even if you do this, the attribute is still editable from any of the other parts of your own script, so it could be the case that a bug in your code writes over the attribute on one of the child objects and detaches it from the parent prototype, so if you change the parent attribute it will no longer cascade and change the static attribute for the child object. See this jsfiddle. In different scenarios we could either Object.freeze(obj) to stop any changes to the child object, or we could set up a setter and getter method in the constructor and access a closure, both of these have associated complexities.

It seems to me that there is not a perfect analogue between the class-based idea of a 'static attribute' and this Javascript implementation. So I think it might be better in the long run to use a different code pattern that is more Javascript friendly. Such as a central datastore or cache or even a dedicated helper object to hold all the necessary static variables.

How to detect the physical connected state of a network cable/connector?

Most modern Linux distributions use NetworkManager for this. You could use D-BUS to listen for the events.

If you want a command-line tool to check the status, you can also use mii-tool, given that you have Ethernet in mind.

How to read a local text file?

You need to check for status 0 (as when loading files locally with XMLHttpRequest, you don't get a status returned because it's not from a Webserver)

function readTextFile(file)
{
    var rawFile = new XMLHttpRequest();
    rawFile.open("GET", file, false);
    rawFile.onreadystatechange = function ()
    {
        if(rawFile.readyState === 4)
        {
            if(rawFile.status === 200 || rawFile.status == 0)
            {
                var allText = rawFile.responseText;
                alert(allText);
            }
        }
    }
    rawFile.send(null);
}

And specify file:// in your filename:

readTextFile("file:///C:/your/path/to/file.txt");

How can I echo the whole content of a .html file in PHP?

Just use:

<?php
    include("/path/to/file.html");
?>

That will echo it as well. This also has the benefit of executing any PHP in the file.

If you need to do anything with the contents, use file_get_contents(),

For example,

<?php
    $pagecontents = file_get_contents("/path/to/file.html");

    echo str_replace("Banana", "Pineapple", $pagecontents);

?>

This doesn't execute code in that file, so be careful if you expect that to work.

I usually use:

include($_SERVER['DOCUMENT_ROOT']."/path/to/file/as/in/url.html");

as then I can move files without breaking the includes.

How to reset AUTO_INCREMENT in MySQL?

it is for empty table:

ALTER TABLE `table_name` AUTO_INCREMENT = 1;

if you have data but you want to tidy up it, i recommend use this :

ALTER TABLE `table_name` DROP `auto_colmn`;
ALTER TABLE `table_name` ADD  `auto_colmn` INT( {many you want} ) NOT NULL AUTO_INCREMENT FIRST ,ADD PRIMARY KEY (`auto_colmn`);

Log4j, configuring a Web App to use a relative path

I've finally done it in this way.

Added a ServletContextListener that does the following:

public void contextInitialized(ServletContextEvent event) {
    ServletContext context = event.getServletContext();
    System.setProperty("rootPath", context.getRealPath("/"));
}

Then in the log4j.properties file:

log4j.appender.file.File=${rootPath}WEB-INF/logs/MyLog.log

By doing it in this way Log4j will write into the right folder as long as you don't use it before the "rootPath" system property has been set. This means that you cannot use it from the ServletContextListener itself but you should be able to use it from anywhere else in the app.

It should work on every web container and OS as it's not dependent on a container specific system property and it's not affected by OS specific path issues. Tested with Tomcat and Orion web containers and on Windows and Linux and it works fine so far.

What do you think?

How to check if a file exists in Ansible?

**

How to check if a file exists in Ansible using when condition

**

Below is the ansible play i used to remove the file when the file exists in the OS end.

 - name: find out /etc/init.d/splunk file exists or not'
      stat:
        path: /etc/init.d/splunk
      register: splunkresult
      tags:
        - always

    - name: 'Remove splunk from init.d file if splunk already running'
      file:
        path: /etc/init.d/splunk
        state: absent
      when: splunkresult.stat.exists == true
      ignore_errors: yes
      tags:
        - always

I have used play condition as like below

when: splunkresult.stat.exists == true --> Remove the file

you can give true/false based on your requirement

when: splunkresult.stat.exists == false
when: splunkresult.stat.exists == true

JavaScript - cannot set property of undefined

you never set d[a] to any value.

Because of this, d[a] evaluates to undefined, and you can't set properties on undefined.

If you add d[a] = {} right after d = {} things should work as expected.

Alternatively, you could use an object initializer:

d[a] = {
    greetings: b,
    data: c
};

Or you could set all the properties of d in an anonymous function instance:

d = new function () {
    this[a] = {
        greetings: b,
        data: c
    };
};

If you're in an environment that supports ES2015 features, you can use computed property names:

d = {
  [a]: {
    greetings: b,
    data: c
  }
};

How to fix broken paste clipboard in VNC on Windows

http://rreddy.blogspot.com/2009/07/vncviewer-clipboard-operations-like.html

Many times you must have observed that clipboard operations like copy/cut and paste suddenly stops workings with the vncviewer. The main reason for this there is a program called as vncconfig responsible for these clipboard transfers. Some times the program may get closed because of some bug in vnc or some other reasons like you closed that window.

To get those clipboard operations back you need to run the program "vncconfig &".

After this your clipboard actions should work fine with out any problems.

Run "vncconfig &" on the client.

Create iOS Home Screen Shortcuts on Chrome for iOS

Can't change the default browser, but try this (found online a while ago). Add a bookmark in Safari called "Open in Chrome" with the following.

javascript:location.href=%22googlechrome%22+location.href.substring(4);

Will open the current page in Chrome. Not as convenient, but maybe someone will find it useful.

Source

Works for me.

how to check for special characters php

preg_match('/'.preg_quote('^\'£$%^&*()}{@#~?><,@|-=-_+-¬', '/').'/', $string);

Encoding Javascript Object to Json string

Unless the variable k is defined, that's probably what's causing your trouble. Something like this will do what you want:

var new_tweets = { };

new_tweets.k = { };

new_tweets.k.tweet_id = 98745521;
new_tweets.k.user_id = 54875;

new_tweets.k.data = { };

new_tweets.k.data.in_reply_to_screen_name = 'other_user';
new_tweets.k.data.text = 'tweet text';

// Will create the JSON string you're looking for.
var json = JSON.stringify(new_tweets);

You can also do it all at once:

var new_tweets = {
  k: {
    tweet_id: 98745521,
    user_id: 54875,
    data: {
      in_reply_to_screen_name: 'other_user',
      text: 'tweet_text'
    }
  }
}

Copy filtered data to another sheet using VBA

When i need to copy data from filtered table i use range.SpecialCells(xlCellTypeVisible).copy. Where the range is range of all data (without a filter).

Example:

Sub copy()
     'source worksheet
     dim ws as Worksheet
     set ws = Application.Worksheets("Data")' set you source worksheet here
     dim data_end_row_number as Integer
     data_end_row_number = ws.Range("B3").End(XlDown).Row.Number
    'enable filter
    ws.Range("B2:F2").AutoFilter Field:=2, Criteria1:="hockey", VisibleDropDown:=True
    ws.Range("B3:F" & data_end_row_number).SpecialCells(xlCellTypeVisible).Copy
    Application.Worksheets("Hoky").Range("B3").Paste
    'You have to add headers to Hoky worksheet
end sub

How do I make a semi transparent background?

Try this:

.transparent
{ 
  opacity:.50;
  -moz-opacity:.50; 
  filter:alpha(opacity=50); 
}

configuring project ':app' failed to find Build Tools revision

It happens because Build Tools revision 24.4.1 doesn't exist.

The latest version is 23.0.2.
These tools is included in the SDK package and installed in the <sdk>/build-tools/ directory.

Don't confuse the Android SDK Tools with SDK Build Tools.

Change in your build.gradle

android {
   buildToolsVersion "23.0.2"
   // ...

}

How do I create a pause/wait function using Qt?

Similar to some answers here, but maybe a little more lightweight

void MyClass::sleepFor(qint64 milliseconds){
    qint64 timeToExitFunction = QDateTime::currentMSecsSinceEpoch()+milliseconds;
    while(timeToExitFunction>QDateTime::currentMSecsSinceEpoch()){
        QApplication::processEvents(QEventLoop::AllEvents, 100);
    }
}

favicon not working in IE

Care to share the URL? Many browsers cope with favicons in (e.g.) png format while IE had often troubles. - Also older versions of IE did not check the html source for the location of the favicon but just single-mindedly tried to get "/favicon.ico" from the webserver.

Excel VBA code to copy a specific string to clipboard

This macro uses late binding to copy text to the clipboard without requiring you to set references. You should be able to just paste and go:

Sub CopyText(Text As String)
    'VBA Macro using late binding to copy text to clipboard.
    'By Justin Kay, 8/15/2014
    Dim MSForms_DataObject As Object
    Set MSForms_DataObject = CreateObject("new:{1C3B4210-F441-11CE-B9EA-00AA006B1A69}")
    MSForms_DataObject.SetText Text
    MSForms_DataObject.PutInClipboard
    Set MSForms_DataObject = Nothing
End Sub

Usage:

Sub CopySelection()
    CopyText Selection.Text
End Sub

Cannot ping AWS EC2 instance

I had the same problem truying to connect from linux server to EC2, you have two make sure about to things that "ALL ICMP" is added from EC2 as shown above and that alone won't work, you have to update Ansible to newest version 2.4, it did not work with my previous version 2.2.

Authenticate Jenkins CI for Github private repository

If you need Jenkins to access more then 1 project you will need to:
1. add public key to one github user account
2. add this user as Owner (to access all projects) or as a Collaborator in every project.

Many public keys for one system user will not work because GitHub will find first matched deploy key and will send back error like "ERROR: Permission to user/repo2 denied to user/repo1"

http://help.github.com/ssh-issues/

Best Practices for Custom Helpers in Laravel 5

Create Helpers.php in app/Helper/Helpers.php

namespace App\Helper
class Helpers
{


}

Add in composer and composer update

 "autoload": {
        "classmap": [
            "database/seeds",
            "database/factories",
            "database","app/Helper/Helpers.php"
        ],
        "psr-4": {
            "App\\": "app/"
        },
         "files": ["app/Helper/Helpers.php"]
    },

use in Controller

use App\Helper\Helpers

use in view change in config->app.php file

   'aliases' => [
    ...
    'Helpers'   => 'App\Helper\Helpers'
    ],

call in view

<?php echo Helpers::function_name();  ?>

How to change Android usb connect mode to charge only?

Nothing worked until I went this way: Settings>Developer options>Default USB configuration now you can choose your default USB connection purpose.

"Repository does not have a release file" error

I have been having this issue for a couple of weeks and finally decided to sit down and try and fix it. I have no interest in config file editing as I'm primarily a Windows user.

In a fit of "clickyness" I noticed that the ubuntu server location was set "for United kingdom". I switched this over to "Main Server" and hey presto... it all stared updating.

So, it seems like the regionalised server (for the UK at least) has a very limited support window so if you are an infrequent user it is likely it will not have a valid upgrade path from your current version to the latest.

Edit: I only just noticted the previous reply, after posting. 100% agree.

Gson - convert from Json to a typed ArrayList<T>

If you want to use Arrays, it's pretty simple.

logs = gson.fromJson(br, JsonLog[].class); // line 6

Provide the JsonLog as an array JsonLog[].class

Java resource as file

ClassLoader.getResourceAsStream and Class.getResourceAsStream are definitely the way to go for loading the resource data. However, I don't believe there's any way of "listing" the contents of an element of the classpath.

In some cases this may be simply impossible - for instance, a ClassLoader could generate data on the fly, based on what resource name it's asked for. If you look at the ClassLoader API (which is basically what the classpath mechanism works through) you'll see there isn't anything to do what you want.

If you know you've actually got a jar file, you could load that with ZipInputStream to find out what's available. It will mean you'll have different code for directories and jar files though.

One alternative, if the files are created separately first, is to include a sort of manifest file containing the list of available resources. Bundle that in the jar file or include it in the file system as a file, and load it before offering the user a choice of resources.

missing FROM-clause entry for table

Because that gtab82 table isn't in your FROM or JOIN clause. You refer gtab82 table in these cases: gtab82.memno and gtab82.memacid

Solr vs. ElasticSearch

I have created a table of major differences between elasticsearch and Solr and splunk, you can use it as 2016 update: enter image description here

Error 500: Premature end of script headers

In my case (referencing a PHP file in the top folder of a Wordpress plugin) I had to change the permissions on that folder. My test environment was fine, but when deployed the folder had 775. I changed it to 755 and it works fine.

How to solve privileges issues when restore PostgreSQL Database

For people using Google Cloud Platform, any error will stop the import process. Personally I encountered two different errors depending on the pg_dump command I issued :

1- The input is a PostgreSQL custom-format dump. Use the pg_restore command-line client to restore this dump to a database.

Occurs when you've tried to dump your DB in a non plain text format. I.e when the command lacks the -Fp or --format=plain parameter. However, if you add it to your command, you may then encounter the following error :

2- SET SET SET SET SET SET CREATE EXTENSION ERROR: must be owner of extension plpgsql

This is a permission issue I have been unable to fix using the command provided in the GCP docs, the tips from this current thread, or following advice from Google Postgres team here. Which recommended to issue the following command :

pg_dump -Fp --no-acl --no-owner -U myusername myDBName > mydump.sql

The only thing that did the trick in my case was manually editing the dump file and commenting out all commands relating to plpgsql.

I hope this helps GCP-reliant souls.

Update :

It's easier to dump the file commenting out extensions, especially since some dumps can be huge : pg_dump ... | grep -v -E '(CREATE\ EXTENSION|COMMENT\ ON)' > mydump.sql

Which can be narrowed down to plpgsql : pg_dump ... | grep -v -E '(CREATE\ EXTENSION\ IF\ NOT\ EXISTS\ plpgsql|COMMENT\ ON\ EXTENSION\ plpgsql)' > mydump.sql

Difference between float and decimal data type

A "float" in most environments is a binary floating-point type. It can accurately store base-2 values (to a certain point), but cannot accurately store many base-10 (decimal) values. Floats are most appropriate for scientific calculations. They're not appropriate for most business-oriented math, and inappropriate use of floats will bite you. Many decimal values can't be exactly represented in base-2. 0.1 can't, for instance, and so you see strange results like 1.0 - 0.1 = 0.8999999.

Decimals store base-10 numbers. Decimal is an good type for most business math (but any built-in "money" type is more appropriate for financial calculations), where the range of values exceeds that provided by integer types, and fractional values are needed. Decimals, as the name implies, are designed for base-10 numbers - they can accurately store decimal values (again, to a certain point).

C# Parsing JSON array of objects

string jsonData1=@"[{""name"":""0"",""price"":""40"",""count"":""1"",""productId"":""4"",""catid"":""4"",""productTotal"":""40"",""orderstatus"":""0"",""orderkey"":""123456789""}]";

                  string jsonData = jsonData1.Replace("\"", "");


                  DataSet ds = new DataSet();
                  DataTable dt = new DataTable();
       JArray array= JArray.Parse(jsonData);

couldnot parse , if the vaule is a string..

look at name : meals , if name : 1 then it will parse

What is the difference between fastcgi and fpm?

What Anthony says is absolutely correct, but I'd like to add that your experience will likely show a lot better performance and efficiency (due not to fpm-vs-fcgi but more to the implementation of your httpd).

For example, I had a quad-core machine running lighttpd + fcgi humming along nicely. I upgraded to a 16-core machine to cope with growth, and two things exploded: RAM usage, and segfaults. I found myself restarting lighttpd every 30 minutes to keep the website up.

I switched to php-fpm and nginx, and RAM usage dropped from >20GB to 2GB. Segfaults disappeared as well. After doing some research, I learned that lighttpd and fcgi don't get along well on multi-core machines under load, and also have memory leak issues in certain instances.

Is this due to php-fpm being better than fcgi? Not entirely, but how you hook into php-fpm seems to be a whole heckuva lot more efficient than how you serve via fcgi.

How to make MySQL table primary key auto increment with some prefix

If you really need this you can achieve your goal with help of separate table for sequencing (if you don't mind) and a trigger.

Tables

CREATE TABLE table1_seq
(
  id INT NOT NULL AUTO_INCREMENT PRIMARY KEY
);
CREATE TABLE table1
(
  id VARCHAR(7) NOT NULL PRIMARY KEY DEFAULT '0', name VARCHAR(30)
);

Now the trigger

DELIMITER $$
CREATE TRIGGER tg_table1_insert
BEFORE INSERT ON table1
FOR EACH ROW
BEGIN
  INSERT INTO table1_seq VALUES (NULL);
  SET NEW.id = CONCAT('LHPL', LPAD(LAST_INSERT_ID(), 3, '0'));
END$$
DELIMITER ;

Then you just insert rows to table1

INSERT INTO Table1 (name) 
VALUES ('Jhon'), ('Mark');

And you'll have

|      ID | NAME |
------------------
| LHPL001 | Jhon |
| LHPL002 | Mark |

Here is SQLFiddle demo