Programs & Examples On #Ieditableobject

IEditableObject is an interface in the .NET framework to allow objects to be edited by a user.

Saving a text file on server using JavaScript

It's not possible to save content to the website using only client-side scripting such as JavaScript and jQuery, but by submitting the data in an AJAX POST request you could perform the other half very easily on the server-side.

However, I would not recommend having raw content such as scripts so easily writeable to your hosting as this could easily be exploited. If you want to learn more about AJAX POST requests, you can read the jQuery API page:

http://api.jquery.com/jQuery.post/

And here are some things you ought to be aware of if you still want to save raw script files on your hosting. You have to be very careful with security if you are handling files like this!

File uploading (most of this applies if sending plain text too if javascript can choose the name of the file) http://www.developershome.com/wap/wapUpload/wap_upload.asp?page=security https://www.owasp.org/index.php/Unrestricted_File_Upload

how to clear localstorage,sessionStorage and cookies in javascript? and then retrieve?

The standard Web Storage, does not say anything about the restoring any of these. So there won't be any standard way to do it. You have to go through the way the browsers implement these, or find a way to backup these before you delete them.

Recommended SQL database design for tags or tagging

If you are using a database that supports map-reduce, like couchdb, storing tags in a plain text field or list field is indeed the best way. Example:

tagcloud: {
  map: function(doc){ 
    for(tag in doc.tags){ 
      emit(doc.tags[tag],1) 
    }
  }
  reduce: function(keys,values){
    return values.length
  }
}

Running this with group=true will group the results by tag name, and even return a count of the number of times that tag was encountered. It's very similar to counting the occurrences of a word in text.

In Excel how to get the left 5 characters of each cell in a specified column and put them into a new column

1) Put =Left(E1,5) in F1

2) Copy F1, then select entire F column and paste.

How to call a VbScript from a Batch File without opening an additional command prompt

If you want to fix vbs associations type

regsvr32 vbscript.dll
regsvr32 jscript.dll
regsvr32 wshext.dll
regsvr32 wshom.ocx
regsvr32 wshcon.dll
regsvr32 scrrun.dll

Also if you can't use vbs due to management then convert your script to a vb.net program which is designed to be easy, is easy, and takes 5 minutes.

Big difference is functions and subs are both called using brackets rather than just functions.

So the compilers are installed on all computers with .NET installed.

See this article here on how to make a .NET exe. Note the sample is for a scripting host. You can't use this, you have to put your vbs code in as .NET code.

How can I convert a VBScript to an executable (EXE) file?

How to break lines at a specific character in Notepad++?

  1. Click Ctrl + h or Search -> Replace on the top menu
  2. Under the Search Mode group, select Regular expression
  3. In the Find what text field, type ],\s*
  4. In the Replace with text field, type ],\n
  5. Click Replace All

Use Mockito to mock some methods but not others

To directly answer your question, yes, you can mock some methods without mocking others. This is called a partial mock. See the Mockito documentation on partial mocks for more information.

For your example, you can do something like the following, in your test:

Stock stock = mock(Stock.class);
when(stock.getPrice()).thenReturn(100.00);    // Mock implementation
when(stock.getQuantity()).thenReturn(200);    // Mock implementation
when(stock.getValue()).thenCallRealMethod();  // Real implementation

In that case, each method implementation is mocked, unless specify thenCallRealMethod() in the when(..) clause.

There is also a possibility the other way around with spy instead of mock:

Stock stock = spy(Stock.class);
when(stock.getPrice()).thenReturn(100.00);    // Mock implementation
when(stock.getQuantity()).thenReturn(200);    // Mock implementation
// All other method call will use the real implementations

In that case, all method implementation are the real one, except if you have defined a mocked behaviour with when(..).

There is one important pitfall when you use when(Object) with spy like in the previous example. The real method will be called (because stock.getPrice() is evaluated before when(..) at runtime). This can be a problem if your method contains logic that should not be called. You can write the previous example like this:

Stock stock = spy(Stock.class);
doReturn(100.00).when(stock).getPrice();    // Mock implementation
doReturn(200).when(stock).getQuantity();    // Mock implementation
// All other method call will use the real implementations

Another possibility may be to use org.mockito.Mockito.CALLS_REAL_METHODS, such as:

Stock MOCK_STOCK = Mockito.mock( Stock.class, CALLS_REAL_METHODS );

This delegates unstubbed calls to real implementations.


However, with your example, I believe it will still fail, since the implementation of getValue() relies on quantity and price, rather than getQuantity() and getPrice(), which is what you've mocked.

Another possibility is to avoid mocks altogether:

@Test
public void getValueTest() {
    Stock stock = new Stock(100.00, 200);
    double value = stock.getValue();
    assertEquals("Stock value not correct", 100.00*200, value, .00001);
}

Database corruption with MariaDB : Table doesn't exist in engine

Something has deleted your ibdata1 file where InnoDB keeps the dictionary. Definitely it's not MySQL who does it.

UPDATE: I made a tutorial on how to fix the error - https://youtu.be/014KbCYayuE

Decompile an APK, modify it and then recompile it

The answers are already kind of outdated or not complete. This maybe works for non-protected apks (no Proguard), but nowadays nobody deploys an unprotected apk. The way I was able to modify a (my) well-protected apk (Proguard, security check which checks for "hacking tools", security check, which checks if the app is repackaged with debug mode,...) is via apktool as already mentioned by other ones here. But nobody explained, that you have to sign the app again.

apktool d app.apk
//generates a folder with smali bytecode files. 

//Do something with it.

apktool b [folder name] -o modified.apk
//generates the modified apk.

//and then
jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore ~/.android/debug.keystore modified.apk androiddebugkey
//signs the app the the debug key (the password is android)

//this apk can be installed on a device.

In my test, the original release apk had no logging. After I decompiled with apktool I exchanged a full byte code file without logging by a full byte code file with logging, re-compiled and signed it and I was able to install it on my device. Afterwards I was able to see the logs in Android Studio as I connected the app to it.

In my opinion, decompiling with dex2jar and JD-GUI is only helpful to get a better understanding what the classes are doing, just for reading purposes. But since everything is proguarded, I'm not sure that you can ever re-compile this half-baked Java code to a working apk. If so, please let me know. I think, the only way is to manipulate the byte code itself as mentioned in this example.

Easiest way to toggle 2 classes in jQuery

The easiest solution is to toggleClass() both classes individually.

Let's say you have an icon:

    <i id="target" class="fa fa-angle-down"></i>

To toggle between fa-angle-down and fa-angle-up do the following:

    $('.sometrigger').click(function(){
        $('#target').toggleClass('fa-angle-down');
        $('#target').toggleClass('fa-angle-up');
    });

Since we had fa-angle-down at the beginning without fa-angle-up each time you toggle both, one leaves for the other to appear.

How to create dictionary and add key–value pairs dynamically?

how about the one liner for creating a key value pair?

let result = { ["foo"]: "some value" };

and some iterator function like reduce to dynamically convert an array to a dictionary

_x000D_
_x000D_
var options = [_x000D_
  { key: "foo", value: 1 },_x000D_
  { key: "bar", value: {id: 2, name: "two"} },_x000D_
  { key: "baz", value: {["active"]: true} },_x000D_
];_x000D_
_x000D_
var result = options.reduce((accumulator, current) => {_x000D_
  accumulator[current.key] = current.value;_x000D_
  return accumulator;_x000D_
}, {});_x000D_
_x000D_
console.log(result);
_x000D_
_x000D_
_x000D_

How to post query parameters with Axios?

In my case, the API responded with a CORS error. I instead formatted the query parameters into query string. It successfully posted data and also avoided the CORS issue.

        var data = {};

        const params = new URLSearchParams({
          contact: this.ContactPerson,
          phoneNumber: this.PhoneNumber,
          email: this.Email
        }).toString();

        const url =
          "https://test.com/api/UpdateProfile?" +
          params;

        axios
          .post(url, data, {
            headers: {
              aaid: this.ID,
              token: this.Token
            }
          })
          .then(res => {
            this.Info = JSON.parse(res.data);
          })
          .catch(err => {
            console.log(err);
          });

What is the difference between typeof and instanceof and when should one be used vs. the other?

no need to overwhelm with ton of above examples, just keep in mind two points of view:

  1. typeof var; is an unary operator will return the original type or root type of var. so that it will return primitive types(string, number, bigint, boolean, undefined, and symbol) or object type.

  2. in case of higher-level object, like built-in objects (String, Number, Boolean, Array..) or complex or custom objects, all of them is object root type, but instance type built base on them is vary(like OOP class inheritance concept), here a instanceof A - a binary operator - will help you, it will go through the prototype chain to check whether constructor of the right operand(A) appears or not.

so whenever you want to check "root type" or work with primitive variable - use "typeof", otherwise using "instanceof".

null is a special case,which is seemingly primitive, but indeed is a special case for object. Using a === null to check null instead.

on the other hand, function is also a special case, which is built-in object but typeof return function

as you can see instanceof must go through the prototype chain meanwhile typeof just check the root type one time so it's easy to understand why typeof is faster than instanceof

How to ensure a <select> form field is submitted when it is disabled?

<select id="example">
    <option value="">please select</option>
    <option value="0" >one</option>
    <option value="1">two</option>
</select>



if (condition){
    //you can't select
    $("#example").find("option").css("display","none");
}else{
   //you can select
   $("#example").find("option").css("display","block");
}

How to get a random number in Ruby

Simplest answer to the question:

rand(0..n)

How to check identical array in most efficient way?

So, what's wrong with checking each element iteratively?

function arraysEqual(arr1, arr2) {
    if(arr1.length !== arr2.length)
        return false;
    for(var i = arr1.length; i--;) {
        if(arr1[i] !== arr2[i])
            return false;
    }

    return true;
}

Typescript: React event types

For those who are looking for a solution to get an event and store something, in my case a HTML 5 element, on a useState here's my solution:

const [anchorElement, setAnchorElement] = useState<HTMLButtonElement | null>(null);

const handleMenu = (event: React.MouseEvent<HTMLButtonElement, MouseEvent>) : void => {
    setAnchorElement(event.currentTarget);
};

How can I check which version of Angular I'm using?

You could also check your package.json:

"dependencies": {
    "@angular/common": "^5.0.0",
    "@angular/compiler": "^5.0.0",
    "@angular/core": "^5.0.0",
    "@angular/forms": "^5.0.0",
    "@angular/http": "^5.0.0",
    "@angular/platform-browser": "^5.0.0",
    "@angular/platform-browser-dynamic": "^5.0.0",
    "@angular/router": "^5.0.0",
  }

(The caret ^ will update you to the most recent major version (the first number). ^4.3.0 will match any 4.x.x release including 4.4.0, but will hold off on 5.0.0. The tilde ~ matches the most recent minor version (the middle number). ~4.3.0 will match all 4.3.x versions, but will miss 4.4.0.)

Python: Binding Socket: "Address already in use"

Try using the SO_REUSEADDR socket option before binding the socket.

comSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

Edit: I see you're still having trouble with this. There is a case where SO_REUSEADDR won't work. If you try to bind a socket and reconnect to the same destination (with SO_REUSEADDR enabled), then TIME_WAIT will still be in effect. It will however allow you to connect to a different host:port.

A couple of solutions come to mind. You can either continue retrying until you can gain a connection again. Or if the client initiates the closing of the socket (not the server), then it should magically work.

How to center the text in a JLabel?

String text = "In early March, the city of Topeka, Kansas," + "<br>" +
              "temporarily changed its name to Google..." + "<br>" + "<br>" +
              "...in an attempt to capture a spot" + "<br>" +
              "in Google's new broadband/fiber-optics project." + "<br>" + "<br>" +"<br>" +
              "source: http://en.wikipedia.org/wiki/Google_server#Oil_Tanker_Data_Center";
JLabel label = new JLabel("<html><div style='text-align: center;'>" + text + "</div></html>");

converting epoch time with milliseconds to datetime

Use datetime.datetime.fromtimestamp:

>>> import datetime
>>> s = 1236472051807 / 1000.0
>>> datetime.datetime.fromtimestamp(s).strftime('%Y-%m-%d %H:%M:%S.%f')
'2009-03-08 09:27:31.807000'

%f directive is only supported by datetime.datetime.strftime, not by time.strftime.

UPDATE Alternative using %, str.format:

>>> import time
>>> s, ms = divmod(1236472051807, 1000)  # (1236472051, 807)
>>> '%s.%03d' % (time.strftime('%Y-%m-%d %H:%M:%S', time.gmtime(s)), ms)
'2009-03-08 00:27:31.807'
>>> '{}.{:03d}'.format(time.strftime('%Y-%m-%d %H:%M:%S', time.gmtime(s)), ms)
'2009-03-08 00:27:31.807'

How can I mock an ES6 module import using Jest?

The claims that you have to mock it at the top of your file are false.

Mock a named ES Import:

// import the named module
import { useWalkthroughAnimations } from '../hooks/useWalkthroughAnimations';

// mock the file and its named export
jest.mock('../hooks/useWalkthroughAnimations', () => ({
  useWalkthroughAnimations: jest.fn()
}));

// do whatever you need to do with your mocked function
useWalkthroughAnimations.mockReturnValue({ pageStyles, goToNextPage, page });

ab load testing

Steps to set up Apache Bench(AB) on windows (IMO - Recommended).

Step 1 - Install Xampp.
Step 2 - Open CMD.
Step 3 - Go to the apache bench destination (cd C:\xampp\apache\bin) from CMD
Step 4 - Paste the command (ab -n 100 -c 10 -k -H "Accept-Encoding: gzip, deflate" http://localhost:yourport/)
Step 5 - Wait for it. Your done

Reading output of a command into an array in Bash

You can use

my_array=( $(<command>) )

to store the output of command <command> into the array my_array.

You can access the length of that array using

my_array_length=${#my_array[@]}

Now the length is stored in my_array_length.

How to get an isoformat datetime string including the default timezone?

With arrow:

>>> import arrow
>>> arrow.now().isoformat()
'2015-04-17T06:36:49.463207-05:00'
>>> arrow.utcnow().isoformat()
'2015-04-17T11:37:17.042330+00:00'

"Could not find a part of the path" error message

The error is self explanatory. The path you are trying to access is not present.

string source_dir = "E:\\Debug\\VipBat\\{0}";

I'm sure that this is not the correct path. Debug folder directly in E: drive looks wrong to me. I guess there must be the project name folder directory present.

Second thing; what is {0} in your string. I am sure that it is an argument placeholder because folder name cannot contains {0} such name. So you need to use String.Format() to replace the actual value.

string source_dir = String.Format("E:\\Debug\\VipBat\\{0}",variableName);

But first check the path existence that you are trying to access.

Read Excel sheet in Powershell

This was extremely helpful for me when trying to automate Cisco SIP phone configuration using an Excel spreadsheet as the source. My only issue was when I tried to make an array and populate it using $array | Add-Member ... as I needed to use it later on to generate the config file. Just defining an array and making it the for loop allowed it to store correctly.

$lastCell = 11 
$startRow, $model, $mac, $nOF, $ext = 1, 1, 5, 6, 7

$excel = New-Object -ComObject excel.application
$wb = $excel.workbooks.open("H:\Strike Network\Phones\phones.xlsx")
$sh = $wb.Sheets.Item(1)
$endRow = $sh.UsedRange.SpecialCells($lastCell).Row

$phoneData = for ($i=1; $i -le $endRow; $i++)
            {
                $pModel = $sh.Cells.Item($startRow,$model).Value2
                $pMAC = $sh.Cells.Item($startRow,$mac).Value2
                $nameOnPhone = $sh.Cells.Item($startRow,$nOF).Value2
                $extension = $sh.Cells.Item($startRow,$ext).Value2
                New-Object PSObject -Property @{ Model = $pModel; MAC = $pMAC; NameOnPhone = $nameOnPhone; Extension = $extension }
                $startRow++
            }

I used to have no issues adding information to an array with Add-Member but that was back in PSv2/3, and I've been away from it a while. Though the simple solution saved me manually configuring 100+ phones and extensions - which nobody wants to do.

height style property doesn't work in div elements

You're loosing your height attribute because you're changing the block element to inline (it's now going to act like a <p>). You're probably picking up that 14px height because of the text height inside your in-line div.

Inline-block may work for your needs, but you may have to implement a work around or two for cross-browser support.

IE supports inline-block, but only for elements that are natively inline.

Validating email addresses using jQuery and regex

This is my solution:

function isValidEmailAddress(emailAddress) {
    var pattern = new RegExp(/^[+a-zA-Z0-9._-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}$/i);
    // alert( pattern.test(emailAddress) );
    return pattern.test(emailAddress);
};

Found that RegExp over here: http://mdskinner.com/code/email-regex-and-validation-jquery

sending email via php mail function goes to spam

What we usually do with e-mail, preventing spam-folders as the end destination, is using either Gmail as the smtp server or Mandrill as the smtp server.

What is the correct syntax of ng-include?

You have to single quote your src string inside of the double quotes:

<div ng-include src="'views/sidepanel.html'"></div>

Source

How to use both onclick and target="_blank"

Instead use window.open():

The syntax is:

window.open(strUrl, strWindowName[, strWindowFeatures]);

Your code should have:

window.open('Prosjektplan.pdf');

Your code should be:

<p class="downloadBoks"
   onclick="window.open('Prosjektplan.pdf')">Prosjektbeskrivelse</p>

How do I create an executable in Visual Studio 2013 w/ C++?

All executable files from Visual Studio should be located in the debug folder of your project, e.g:

Visual Studio Directory: c:\users\me\documents\visual studio

Then the project which was called 'hello world' would be in the directory:

c:\users\me\documents\visual studio\hello world

And your exe would be located in:

c:\users\me\documents\visual studio\hello world\Debug\hello world.exe

Note the exe being named the same as the project.

Otherwise, you could publish it to a specified folder of your choice which comes with an installation, which would be good if you wanted to distribute it quickly

EDIT:

Everytime you build your project in VS, the exe is updated with the new one according to the code (as long as it builds without errors). When you publish it, you can choose the location, aswell as other factors, and the setup exe will be in that location, aswell as some manifest files and other files about the project.

How can I style the border and title bar of a window in WPF?

You need to set

WindowStyle="None", AllowsTransparency="True" and optionally ResizeMode="NoResize"
and then set the Style property of the window to your custom window style, where you design the appearance of the window (title bar, buttons, border) to anything you want and display the window contents in a ContentPresenter.

This seems to be a good article on how you can achieve this, but there are many other articles on the internet.

Effect of NOLOCK hint in SELECT statements

1) Yes, a select with NOLOCK will complete faster than a normal select.

2) Yes, a select with NOLOCK will allow other queries against the effected table to complete faster than a normal select.

Why would this be?

NOLOCK typically (depending on your DB engine) means give me your data, and I don't care what state it is in, and don't bother holding it still while you read from it. It is all at once faster, less resource-intensive, and very very dangerous.

You should be warned to never do an update from or perform anything system critical, or where absolute correctness is required using data that originated from a NOLOCK read. It is absolutely possible that this data contains rows that were deleted during the query's run or that have been deleted in other sessions that have yet to be finalized. It is possible that this data includes rows that have been partially updated. It is possible that this data contains records that violate foreign key constraints. It is possible that this data excludes rows that have been added to the table but have yet to be committed.

You really have no way to know what the state of the data is.

If you're trying to get things like a Row Count or other summary data where some margin of error is acceptable, then NOLOCK is a good way to boost performance for these queries and avoid having them negatively impact database performance.

Always use the NOLOCK hint with great caution and treat any data it returns suspiciously.

No connection could be made because the target machine actively refused it?

I've received this error from referencing services located on a WCFHost from my web tier. What worked for me may not apply to everyone, but I'm leaving this answer for those whom it may. The port number for my WCFHost was randomly updated by IIS, I simply had to update the end routes to the svc references in my web config. Problem solved.

Enabling the OpenSSL in XAMPP

Yes, you must open php.ini and remove the semicolon to:

;extension=php_openssl.dll

If you don't have that line, check that you have the file (In my PC is on D:\xampp\php\ext) and add this to php.ini in the "Dynamic Extensions" section:

extension=php_openssl.dll

Things have changed for PHP > 7. This is what i had to do for PHP 7.2.

Step: 1: Uncomment extension=openssl

Step: 2: Uncomment extension_dir = "ext"

Step: 3: Restart xampp.

Done.

Explanation: ( From php.ini )

If you wish to have an extension loaded automatically, use the following syntax:

extension=modulename

Note : The syntax used in previous PHP versions (extension=<ext>.so and extension='php_<ext>.dll) is supported for legacy reasons and may be deprecated in a future PHP major version. So, when it is possible, please move to the new (extension=<ext>) syntax.

Special Note: Be sure to appropriately set the extension_dir directive.

C#: How to make pressing enter in a text box trigger a button, yet still allow shortcuts such as "Ctrl+A" to get through?

Can you not use AcceptButton in for the Forms Properties Window? This sets the default behaviour for the Enter key press, but you are still able to use other shortcuts.

Model summary in pytorch

Simplest to remember (not as pretty as Keras):

print(model)

This also work:

repr(model)

If you just want the number of parameters:

sum([param.nelement() for param in model.parameters()])

From: Is there similar pytorch function as model.summary() as keras? (forum.PyTorch.org)

Programmatically get own phone number in iOS

As you probably all ready know if you use the following line of code, your app will be rejected by Apple

NSString *num = [[NSUserDefaults standardUserDefaults] stringForKey:@"SBFormattedPhoneNumber"];

here is a reference

http://ayeapi.blogspot.com/2009/12/sbformatphonenumber-is-lie.html

you can use the following information instead

NSString *phoneName = [[UIDevice currentDevice] name];

NSString *phoneUniqueIdentifier = [[UIDevice currentDevice] uniqueIdentifier];

and so on

@property(nonatomic,readonly,retain) NSString    *name;              // e.g. "My iPhone"
@property(nonatomic,readonly,retain) NSString    *model;             // e.g. @"iPhone", @"iPod Touch"
@property(nonatomic,readonly,retain) NSString    *localizedModel;    // localized version of model
@property(nonatomic,readonly,retain) NSString    *systemName;        // e.g. @"iPhone OS"
@property(nonatomic,readonly,retain) NSString    *systemVersion;     // e.g. @"2.0"
@property(nonatomic,readonly) UIDeviceOrientation orientation;       // return current device orientation
@property(nonatomic,readonly,retain) NSString    *uniqueIdentifier;  // a string unique to each device based on various hardware info.

Hope this helps!

Handler vs AsyncTask vs Thread

Thread

When you start an app, a process is created to execute the code. To efficiently use computing resource, threads can be started within the process so that multiple tasks can be executed at the time. So threads allow you to build efficient apps by utilizing cpu efficiently without idle time.

In Android, all components execute on a single called main thread. Android system queue tasks and execute them one by one on the main thread. When long running tasks are executed, app become unresponsive.

To prevent this, you can create worker threads and run background or long running tasks.

Handler

Since android uses single thread model, UI components are created non-thread safe meaning only the thread it created should access them that means UI component should be updated on main thread only. As UI component run on the main thread, tasks which run on worker threads can not modify UI components. This is where Handler comes into picture. Handler with the help of Looper can connect to new thread or existing thread and run code it contains on the connected thread.

Handler makes it possible for inter thread communication. Using Handler, background thread can send results to it and the handler which is connected to main thread can update the UI components on the main thread.

AsyncTask

AsyncTask provided by android uses both thread and handler to make running simple tasks in the background and updating results from background thread to main thread easy.

Please see android thread, handler, asynctask and thread pools for examples.

How to return a value from try, catch, and finally?

It is because you are in a try statement. Since there could be an error, sum might not get initialized, so put your return statement in the finally block, that way it will for sure be returned.

Make sure that you initialize sum outside the try/catch/finally so that it is in scope.

Saving ssh key fails

It looks like you are executing that command from a DOS session (see this thread), and that means you need to create the .ssh directory before said command.

Or you can execute it from the bash session (part of the msysgit distribution), and it should work.

What are the differences between the BLOB and TEXT datatypes in MySQL?

TEXT and CHAR will convert to/from the character set they have associated with time. BLOB and BINARY simply store bytes.

BLOB is used for storing binary data while Text is used to store large string.

BLOB values are treated as binary strings (byte strings). They have no character set, and sorting and comparison are based on the numeric values of the bytes in column values.

TEXT values are treated as nonbinary strings (character strings). They have a character set, and values are sorted and compared based on the collation of the character set.

http://dev.mysql.com/doc/refman/5.0/en/blob.html

How to get a tab character?

I use <span style="display: inline-block; width: 2ch;">&#9;</span> for a two characters wide tab.

SFTP in Python? (platform independent)

Twisted can help you with what you are doing, check out their documentation, there are plenty of examples. Also it is a mature product with a big developer/user community behind it.

Change default icon

Your application icon shows in the taskbar. The icon on the topleft (window) is the form-icon. Go to your form and fill the property "icon" with the same icon; problem solved. You don't need to put the icon in the outputfolder (that's just for setups).

How to underline a UILabel in swift?

Just a little fix for the Shlome answer in Swift 4 and Xcode 9.

extension UILabel {
    func underline() {
        if let textString = self.text {
            let attributedString = NSMutableAttributedString(string: textString)
            attributedString.addAttribute(NSAttributedStringKey.underlineStyle,
                                          value: NSUnderlineStyle.styleSingle.rawValue,
                                          range: NSRange(location: 0, length: attributedString.length - 1))
            attributedText = attributedString
        }
    }
}

    extension UIButton {
        func underline() {
            let attributedString = NSMutableAttributedString(string: (self.titleLabel?.text!)!)
            attributedString.addAttribute(NSAttributedStringKey.underlineStyle,
                                          value: NSUnderlineStyle.styleSingle.rawValue,
                                          range: NSRange(location: 0, length: (self.titleLabel?.text!.count)!))
            self.setAttributedTitle(attributedString, for: .normal)
        }
    }

onclick on a image to navigate to another page using Javascript

Because it makes these things so easy, you could consider using a JavaScript library like jQuery to do this:

<script>
    $(document).ready(function() {
        $('img.thumbnail').click(function() {
            window.location.href = this.id + '.html';
        });
    });
</script>

Basically, it attaches an onClick event to all images with class thumbnail to redirect to the corresponding HTML page (id + .html). Then you only need the images in your HTML (without the a elements), like this:

<img src="bottle.jpg" alt="bottle" class="thumbnail" id="bottle" />
<img src="glass.jpg" alt="glass" class="thumbnail" id="glass" />

How to find the length of a string in R

See ?nchar. For example:

> nchar("foo")
[1] 3
> set.seed(10)
> strn <- paste(sample(LETTERS, 10), collapse = "")
> strn
[1] "NHKPBEFTLY"
> nchar(strn)
[1] 10

What is the difference between buffer and cache memory in Linux?

Explained by Red Hat:

Cache Pages:

A cache is the part of the memory which transparently stores data so that future requests for that data can be served faster. This memory is utilized by the kernel to cache disk data and improve i/o performance.

The Linux kernel is built in such a way that it will use as much RAM as it can to cache information from your local and remote filesystems and disks. As the time passes over various reads and writes are performed on the system, kernel tries to keep data stored in the memory for the various processes which are running on the system or the data that of relevant processes which would be used in the near future. The cache is not reclaimed at the time when process get stop/exit, however when the other processes requires more memory then the free available memory, kernel will run heuristics to reclaim the memory by storing the cache data and allocating that memory to new process.

When any kind of file/data is requested then the kernel will look for a copy of the part of the file the user is acting on, and, if no such copy exists, it will allocate one new page of cache memory and fill it with the appropriate contents read out from the disk.

The data that is stored within a cache might be values that have been computed earlier or duplicates of original values that are stored elsewhere in the disk. When some data is requested, the cache is first checked to see whether it contains that data. The data can be retrieved more quickly from the cache than from its source origin.

SysV shared memory segments are also accounted as a cache, though they do not represent any data on the disks. One can check the size of the shared memory segments using ipcs -m command and checking the bytes column.

Buffers:

Buffers are the disk block representation of the data that is stored under the page caches. Buffers contains the metadata of the files/data which resides under the page cache. Example: When there is a request of any data which is present in the page cache, first the kernel checks the data in the buffers which contain the metadata which points to the actual files/data contained in the page caches. Once from the metadata the actual block address of the file is known, it is picked up by the kernel for processing.

Resolve conflicts using remote changes when pulling from Git remote

If you truly want to discard the commits you've made locally, i.e. never have them in the history again, you're not asking how to pull - pull means merge, and you don't need to merge. All you need do is this:

# fetch from the default remote, origin
git fetch
# reset your current branch (master) to origin's master
git reset --hard origin/master

I'd personally recommend creating a backup branch at your current HEAD first, so that if you realize this was a bad idea, you haven't lost track of it.

If on the other hand, you want to keep those commits and make it look as though you merged with origin, and cause the merge to keep the versions from origin only, you can use the ours merge strategy:

# fetch from the default remote, origin
git fetch
# create a branch at your current master
git branch old-master
# reset to origin's master
git reset --hard origin/master
# merge your old master, keeping "our" (origin/master's) content
git merge -s ours old-master

How to set conditional breakpoints in Visual Studio?

If you came from Google, this answer might be what you are searching for.

  1. Click Debug> New BreakPoint > Function Breakpoint enter image description here

  2. there choose the conditional Breakpoint.

Check if value exists in the array (AngularJS)

You could use indexOf function.

if(list.indexOf(createItem.artNr) !== -1) {
  $scope.message = 'artNr already exists!';
}

More about indexOf:

Bind failed: Address already in use

As mentioned above the port is in use already. This could be due to several reasons

  1. some other application is already using it.
  2. The port is in close_wait state when your program is waiting for the other end to close the program.refer (https://unix.stackexchange.com/questions/10106/orphaned-connections-in-close-wait-state).
  3. The program might be in time_wait state. you can wait or use socket option SO_REUSEADDR as mentioned in another post.

Do netstat -a | grep <portno> to check the port state.

How can I set a custom baud rate on Linux?

You can set a custom baud rate using the stty command on Linux. For example, to set a custom baud rate of 567890 on your serial port /dev/ttyX0, use the command:

stty -F /dev/ttyX0 567890

How to get week number of the month from the date in sql server 2008

You can simply get week number by getting minimum week number of month and deduct it from week number. Suppose you have a table with dates

select
    emp_id, dt , datepart(wk,dt) - (select min(datepart(wk,dt))
from
    workdates ) + 1 from workdates

How to do fade-in and fade-out with JavaScript and CSS

Here is a more efficient way of fading out an element:

function fade(element) {
    var op = 1;  // initial opacity
    var timer = setInterval(function () {
        if (op <= 0.1){
            clearInterval(timer);
            element.style.display = 'none';
        }
        element.style.opacity = op;
        element.style.filter = 'alpha(opacity=' + op * 100 + ")";
        op -= op * 0.1;
    }, 50);
}

you can do the reverse for fade in

setInterval or setTimeout should not get a string as argument

google the evils of eval to know why

And here is a more efficient way of fading in an element.

function unfade(element) {
    var op = 0.1;  // initial opacity
    element.style.display = 'block';
    var timer = setInterval(function () {
        if (op >= 1){
            clearInterval(timer);
        }
        element.style.opacity = op;
        element.style.filter = 'alpha(opacity=' + op * 100 + ")";
        op += op * 0.1;
    }, 10);
}

JavaScript alert not working in Android WebView

if you wish to hide URL from the user, Show an AlertDialog as below.

myWebView.setWebChromeClient(new WebChromeClient() {

            @Override
            public boolean onJsAlert(WebView view, String url, String message, JsResult result) {
                Log.d(TAG, "onJsAlert url: " + url + "; message: " + message);
                AlertDialog.Builder builder = new AlertDialog.Builder(
                        mContext);
                builder.setMessage(message)
                        .setNeutralButton("OK", new OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int arg1) {
                                dialog.dismiss();
                            }
                        }).show();
                result.cancel();
                return true;
            }
    }

How to reset the use/password of jenkins on windows?

I had the same problem, no possible connection at second login.

After solving the problem (useSecurity, etc., see above), I realized that admin/admin worked (with Synology, it that's relevant).

What is the purpose of "&&" in a shell command?

Furthermore, you also have || which is the logical or, and also ; which is just a separator which doesn't care what happend to the command before.

$ false || echo "Oops, fail"
Oops, fail

$ true || echo "Will not be printed"
$  

$ true && echo "Things went well"
Things went well

$ false && echo "Will not be printed"
$

$ false ; echo "This will always run"
This will always run

Some details about this can be found here Lists of Commands in the Bash Manual.

how to programmatically fake a touch event to a UIButton?

For Xamarin iOS

btnObj.SendActionForControlEvents(UIControlEvent.TouchUpInside);

Reference

What is the use of static variable in C#? When to use it? Why can't I declare the static variable inside method?

You don't need to instantiate an object, because yau are going to use a static variable: Console.WriteLine(Book.myInt);

Saving an Excel sheet in a current directory with VBA

If the Path is omitted the file will be saved automaticaly in the current directory. Try something like this:

ActiveWorkbook.SaveAs "Filename.xslx"

Substring in VBA

You can first find the position of the string in this case ":"

'position = InStr(StringToSearch, StringToFind)
position = InStr(StringToSearch, ":")

Then use Left(StringToCut, NumberOfCharacterToCut)

Result = Left(StringToSearch, position -1)

Cannot open include file: 'stdio.h' - Visual Studio Community 2017 - C++ Error

Faced the same issue, another solution is to add default includes, this fixed the problem for me:

$(IncludePath);

Which to use <div class="name"> or <div id="name">?

Classes should be used when you have multiple similar elements.

Ex: Many div's displaying song lyrics, you could assign them a class of lyrics since they are all similar.

ID's must be unique! They are used to target specific elements

Ex: An input for a users email could have the ID txtEmail -- No other element should have this ID.

What's a Good Javascript Time Picker?

You could read jQuery creator John Resig's post about it here: http://ejohn.org/blog/picking-time/.

Java file path in Linux

I think Todd is correct, but I think there's one other thing you should consider. You can reliably get the home directory from the JVM at runtime, and then you can create files objects relative to that location. It's not that much more trouble, and it's something you'll appreciate if you ever move to another computer or operating system.

File homedir = new File(System.getProperty("user.home"));
File fileToRead = new File(homedir, "java/ex.txt");

What is the significance of #pragma marks? Why do we need #pragma marks?

While searching for doc to point to about how pragma are directives for the compiler, I found this NSHipster article that does the job pretty well.

I hope you'll enjoy the reading

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

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

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

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

Property [title] does not exist on this collection instance

A person might get this while working with factory functions, so I can confirm this is valid syntax:

$user = factory(User::class, 1)->create()->first();

You might see the collection instance error if you do something like:

$user = factory(User::class, 1)->create()->id;

so change it to:

$user = factory(User::class, 1)->create()->first()->id;

Can we call the function written in one JavaScript in another JS file?

The function could be called as if it was in the same JS File as long as the file containing the definition of the function has been loaded before the first use of the function.

I.e.

File1.js

function alertNumber(number) {
    alert(number);
}

File2.js

function alertOne() {
     alertNumber("one");
}

HTML

<head>
....
    <script src="File1.js" type="text/javascript"></script> 
    <script src="File2.js" type="text/javascript"></script> 
....
</head>
<body>
....
    <script type="text/javascript">
       alertOne();
    </script>
....
</body>

The other way won't work. As correctly pointed out by Stuart Wakefield. The other way will also work.

HTML

<head>
....
    <script src="File2.js" type="text/javascript"></script> 
    <script src="File1.js" type="text/javascript"></script> 
....
</head>
<body>
....
    <script type="text/javascript">
       alertOne();
    </script>
....
</body>

What will not work would be:

HTML

<head>
....
    <script src="File2.js" type="text/javascript"></script> 
    <script type="text/javascript">
       alertOne();
    </script>
    <script src="File1.js" type="text/javascript"></script> 
....
</head>
<body>
....
</body>

Although alertOne is defined when calling it, internally it uses a function that is still not defined (alertNumber).

Make Font Awesome icons in a circle?

This is the best and most precise solution I've found so far.

CSS:

.social .fa {
      margin-right: 1rem;
      border: 2px #fff solid;
      border-radius: 50%;
      height: 20px;
      width: 20px;
      line-height: 20px;
      text-align: center;
      padding: 0.5rem;
    }

Check if a string contains an element from a list (of strings)

As I needed to check if there are items from a list in a (long) string, I ended up with this one:

listOfStrings.Any(x => myString.ToUpper().Contains(x.ToUpper()));

Or in vb.net:

listOfStrings.Any(Function(x) myString.ToUpper().Contains(x.ToUpper()))

Best Practices for mapping one object to another

Efran Cobisi's suggestion of using an Auto Mapper is a good one. I have used Auto Mapper for a while and it worked well, until I found the much faster alternative, Mapster.

Given a large list or IEnumerable, Mapster outperforms Auto Mapper. I found a benchmark somewhere that showed Mapster being 6 times as fast, but I could not find it again. You could look it up and then, if it is suits you, use Mapster.

How can I set my Cygwin PATH to find javac?

If you are still finding that the default wrong Java version (1.7) is being used instead of your Java home directory, then all you need to do is simply change the order of your PATH variable to set JAVA_HOME\bin before your Windows directory in your PATH variable, save it and restart cygwin. Test it out to make sure everything will work fine. It should not have any adverse effect because you want your own Java version to override the default which comes with Windows. Good luck!

VBA error 1004 - select method of range class failed

You can't select a range without having first selected the sheet it is in. Try to select the sheet first and see if you still get the problem:

sourceSheetSum.Select
sourceSheetSum.Range("C3").Select

SQL Server : error converting data type varchar to numeric

thanks, try this instead

Select 
  STR(account_code) as account_code_Numeric,
  descr 
from account 
where  STR(account_code) = 1

I'm happy to help you

Remove all special characters with RegExp

Plain Javascript regex does not handle Unicode letters.

Do not use [^\w\s], this will remove letters with accents (like àèéìòù), not to mention to Cyrillic or Chinese, letters coming from such languages will be completed removed.

You really don't want remove these letters together with all the special characters. You have two chances:

  • Add in your regex all the special characters you don't want remove,
    for example: [^èéòàùì\w\s].
  • Have a look at xregexp.com. XRegExp adds base support for Unicode matching via the \p{...} syntax.

_x000D_
_x000D_
var str = "????::: résd,$%& adùf"
var search = XRegExp('([^?<first>\\pL ]+)');
var res = XRegExp.replace(str, search, '',"all");

console.log(res); // returns "????::: resd,adf"
console.log(str.replace(/[^\w\s]/gi, '') ); // returns " rsd adf"
console.log(str.replace(/[^\wèéòàùì\s]/gi, '') ); // returns " résd adùf"
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/xregexp/3.1.1/xregexp-all.js"></script>
_x000D_
_x000D_
_x000D_

Is it a good practice to use an empty URL for a HTML form's action attribute? (action="")

Just use

?

<form action="?" method="post" enctype="multipart/form-data" name="myForm" id="myForm">

It doesn't violate HTML5 standards.

Change Input to Upper Case

I couldn't find the text-uppercase in Bootstrap referred to in one of the answers. No matter, I created it;

.text-uppercase {
  text-transform: uppercase;
}

This displays text in uppercase, but the underlying data is not transformed in this way. So in jquery I have;

$(".text-uppercase").keyup(function () {
    this.value = this.value.toLocaleUpperCase();
});

This will change the underlying data wherever you use the text-uppercase class.

#1142 - SELECT command denied to user ''@'localhost' for table 'pma_table_uiprefs'

You use this command in phpMyAdmin SQL Part:

GRANT SELECT , INSERT , UPDATE , DELETE ON phpmyadmin.* TO  `pma`@`localhost` IDENTIFIED BY  ''

What's the best mock framework for Java?

I started using mocks through JMock, but eventually transitioned to use EasyMock. EasyMock was just that, --easier-- and provided a syntax that felt more natural. I haven't switched since.

How do I get Maven to use the correct repositories?

I think what you have missed here is this:

https://maven.apache.org/settings.html#Servers

The repositories for download and deployment are defined by the repositories and distributionManagement elements of the POM. However, certain settings such as username and password should not be distributed along with the pom.xml. This type of information should exist on the build server in the settings.xml.

This is the prefered way of using custom repos. So probably what is happening is that the url of this repo is in settings.xml of the build server.

Once you get hold of the url and credentials, you can put them in your machine here: ~/.m2/settings.xml like this:

<settings ...> 

        .
        .
        .
        <servers>
            <server>
              <id>internal-repository-group</id>
              <username>YOUR-USERNAME-HERE</username>
              <password>YOUR-PASSWORD-HERE</password>
            </server>
        </servers>
</settings>

EDIT:

You then need to refer this repository into project POM. The id internal-repository-group can be used in every project. You can setup multiple repos and credentials setting using different IDs in settings xml.

The advantage of this approach is that project can be shared without worrying about the credentials and don't have to mention the credentials in every project.

Following is a sample pom of a project using "internal-repository-group"

<repositories>
    <repository>
        <id>internal-repository-group</id>
        <name>repo-name</name>
        <url>http://project.com/yourrepourl/</url>
        <layout>default</layout>
        <releases>
            <enabled>true</enabled>
            <updatePolicy>never</updatePolicy>
        </releases>
        <snapshots>
            <enabled>true</enabled>
            <updatePolicy>never</updatePolicy>
        </snapshots>
    </repository>
</repositories>

How to add column if not exists on PostgreSQL?

the below function will check the column if exist return appropriate message else it will add the column to the table.

create or replace function addcol(schemaname varchar, tablename varchar, colname varchar, coltype varchar)
returns varchar 
language 'plpgsql'
as 
$$
declare 
    col_name varchar ;
begin 
      execute 'select column_name from information_schema.columns  where  table_schema = ' ||
      quote_literal(schemaname)||' and table_name='|| quote_literal(tablename) || '   and    column_name= '|| quote_literal(colname)    
      into   col_name ;   

      raise info  ' the val : % ', col_name;
      if(col_name is null ) then 
          col_name := colname;
          execute 'alter table ' ||schemaname|| '.'|| tablename || ' add column '|| colname || '  ' || coltype; 
      else
           col_name := colname ||' Already exist';
      end if;
return col_name;
end;
$$

How to analyze disk usage of a Docker container

I use docker stats $(docker ps --format={{.Names}}) --no-stream to get :

  1. CPU usage,
  2. Mem usage/Total mem allocated to container (can be allocate with docker run command)
  3. Mem %
  4. Block I/O
  5. Net I/O

How to pause a YouTube player when hiding the iframe?

You can stop the video by calling the stopVideo() method on the YouTube player instance before hiding the div e.g.

player.stopVideo()

For more details see here: http://code.google.com/apis/youtube/js_api_reference.html#Playback_controls

Input length must be multiple of 16 when decrypting with padded cipher

Had a similar issue. But it is important to understand the root cause and it may vary for different use cases.

Scenario 1
You are trying to decrypt a value which was not encoded correctly in the first place.

byte[] encryptedBytes = Base64.decodeBase64(encryptedBase64String);

If the String is misconfigured for certain reason or has not been encoded correctly, you would see the error " Input length must be multiple of 16 when decrypting with padded cipher"

Scenario 2
Now if by any chance you are using this encoded string in url (trying to pass in the base64Encoded value in url, it will fail. You should do URLEncoding and then pass in the token, it will work.

Scenario 3
When integrating with one of the vendors, we found that we had to do encryption of Base64 using URLEncoder but then we need not decode it because it was done internally by the Vendor

Copying Code from Inspect Element in Google Chrome

you dont have to do that in the Google chrome. Use the Internet explorer it offers the option to copy the css associated and after you copy and paste select the style and put that into another file .css to call into that html which you have created. Hope this will solve you problem than anything else:)

error: This is probably not a problem with npm. There is likely additional logging output above

Delete node_modules

rm -r node_modules

install packages again

npm install

How to capture the browser window close event?

The beforeunload event fires whenever the user leaves your page for any reason.

For example, it will be fired if the user submits a form, clicks a link, closes the window (or tab), or goes to a new page using the address bar, search box, or a bookmark.

You could exclude form submissions and hyperlinks (except from other frames) with the following code:

var inFormOrLink;
$('a').on('click', function() { inFormOrLink = true; });
$('form').on('submit', function() { inFormOrLink = true; });

$(window).on("beforeunload", function() { 
    return inFormOrLink ? "Do you really want to close?" : null; 
})

For jQuery versions older than 1.7, try this:

var inFormOrLink;
$('a').live('click', function() { inFormOrLink = true; });
$('form').bind('submit', function() { inFormOrLink = true; });

$(window).bind("beforeunload", function() { 
    return inFormOrLink ? "Do you really want to close?" : null; 
})

The live method doesn't work with the submit event, so if you add a new form, you'll need to bind the handler to it as well.

Note that if a different event handler cancels the submit or navigation, you will lose the confirmation prompt if the window is actually closed later. You could fix that by recording the time in the submit and click events, and checking if the beforeunload happens more than a couple of seconds later.

How to get past the login page with Wget?

I wanted a one-liner that didn't download any files; here is an example of piping the cookie output into the next request. I only tested the following on Gentoo, but it should work in most *nix environments:

wget -q -O /dev/null --save-cookies /dev/stdout --post-data 'u=user&p=pass' 'http://example.com/login' | wget -q -O - --load-cookies /dev/stdin 'http://example.com/private/page'

(This is one line, though it likely wraps on your browser)

If you want the output saved to a file, change -O - to -O /some/file/name.ext

Checking to see if a DateTime variable has had a value assigned

I generally prefer, where possible, to use the default value of value types to determine whether they've been set. This obviously isn't possible all the time, especially with ints - but for DateTimes, I think reserving the MinValue to signify that it hasn't been changed is fair enough. The benefit of this over nullables is that there's one less place where you'll get a null reference exception (and probably lots of places where you don't have to check for null before accessing it!)

Get current domain

Try $_SERVER['SERVER_NAME'].

Tips: Create a PHP file that calls the function phpinfo() and see the "PHP Variables" section. There are a bunch of useful variables we never think of there.

How to show the Project Explorer window in Eclipse

If none of the above solutions work, Try Window-> New Window

angular 2 ngIf and CSS transition/animation

According to the latest angular 2 documentation you can animate "Entering and Leaving" elements (like in angular 1).

Example of simple fade animation:

In relevant @Component add:

animations: [
  trigger('fadeInOut', [
    transition(':enter', [   // :enter is alias to 'void => *'
      style({opacity:0}),
      animate(500, style({opacity:1})) 
    ]),
    transition(':leave', [   // :leave is alias to '* => void'
      animate(500, style({opacity:0})) 
    ])
  ])
]

Do not forget to add imports

import {style, state, animate, transition, trigger} from '@angular/animations';

The relevant component's html's element should look like:

<div *ngIf="toggle" [@fadeInOut]>element</div>

I built example of slide and fade animation here.

Explanation on 'void' and '*':

  • void is the state when ngIf is set to false (it applies when the element is not attached to a view).
  • * - There can be many animation states (read more in docs). The * state takes precedence over all of them as a "wildcard" (in my example this is the state when ngIf is set to true).

Notice (taken from angular docs):

Extra declare inside the app module, import { BrowserAnimationsModule } from '@angular/platform-browser/animations';

Angular animations are built on top of the standard Web Animations API and run natively on browsers that support it. For other browsers, a polyfill is required. Grab web-animations.min.js from GitHub and add it to your page.

How to avoid a System.Runtime.InteropServices.COMException?

I came across System.Runtime.InteropServices.COMException while opening a project solution. Sometimes user doesn't have enough priveleges to run some COM Methods. I ran Visual Studio as Administrator and the exception was gone.

Initializing C dynamic arrays

You need to allocate a block of memory and use it as an array as:

int *arr = malloc (sizeof (int) * n); /* n is the length of the array */
int i;

for (i=0; i<n; i++)
{
  arr[i] = 0;
}

If you need to initialize the array with zeros you can also use the memset function from C standard library (declared in string.h).

memset (arr, 0, sizeof (int) * n);

Here 0 is the constant with which every locatoin of the array will be set. Note that the last argument is the number of bytes to be set the the constant. Because each location of the array stores an integer therefore we need to pass the total number of bytes as this parameter.

Also if you want to clear the array to zeros, then you may want to use calloc instead of malloc. calloc will return the memory block after setting the allocated byte locations to zero.

After you have finished, free the memory block free (arr).

EDIT1

Note that if you want to assign a particular integer in locations of an integer array using memset then it will be a problem. This is because memset will interpret the array as a byte array and assign the byte you have given, to every byte of the array. So if you want to store say 11243 in each location then it will not be possible.

EDIT2

Also note why every time setting an int array to 0 with memset may not work: Why does "memset(arr, -1, sizeof(arr)/sizeof(int))" not clear an integer array to -1? as pointed out by @Shafik Yaghmour

Convert UNIX epoch to Date object

Go via POSIXct and you want to set a TZ there -- here you see my (Chicago) default:

R> val <- 1352068320
R> as.POSIXct(val, origin="1970-01-01")
[1] "2012-11-04 22:32:00 CST"
R> as.Date(as.POSIXct(val, origin="1970-01-01"))
[1] "2012-11-05" 
R> 

Edit: A few years later, we can now use the anytime package:

R> library(anytime)
R> anytime(1352068320)
[1] "2012-11-04 16:32:00 CST"
R> anydate(1352068320)
[1] "2012-11-04"
R> 

Note how all this works without any format or origin arguments.

How can I determine browser window size on server side C#

So here is how you will do it.

Write a javascript function which fires whenever the window is resized.

window.onresize = function(event) {
    var height=$(window).height();
    var width=$(window).width();
    $.ajax({
     url: "/getwindowsize.ashx",
     type: "POST",
     data : { Height: height, 
              Width:width, 
              selectedValue:selectedValue },
     contentType: "application/json; charset=utf-8",
     dataType: "json",
     success: function (response) { 
           // do stuff
     }

}

Codebehind of Handler:

 public class getwindowsize : IHttpHandler {

public void ProcessRequest (HttpContext context) {
    context.Response.ContentType = "application/json";
     string Height = context.Request.QueryString["Height"]; 
     string Width = context.Request.QueryString["Width"]; 
    }

How do I use floating-point division in bash?

bash

As noted by others, bash does not support floating point arithmetic, although you could fake it with some fixed decimal trickery, e.g. with two decimals:

echo $(( 100 * 1 / 3 )) | sed 's/..$/.&/'

Output:

.33

See Nilfred's answer for a similar but more concise approach.

Alternatives

Besides the mentioned bc and awk alternatives there are also the following:

clisp

clisp -x '(/ 1.0 3)'

with cleaned up output:

clisp --quiet -x '(/ 1.0 3)'

or through stdin:

echo '(/ 1.0 3)' | clisp --quiet | tail -n1

dc

echo 2k 1 3 /p | dc

genius cli calculator

echo 1/3.0 | genius

ghostscript

echo 1 3 div = | gs -dNODISPLAY -dQUIET | sed -n '1s/.*>//p' 

gnuplot

echo 'pr 1/3.' | gnuplot

Imagemagick

convert xc: -format '%[fx:1/3]' info:

or through stdin:

echo 1/3 | { convert xc: -format "%[fx:$(cat)]" info:; }

jq

echo 1/3 | jq -nf /dev/stdin

Or:

jq -n 1/3

ksh

echo 'print $(( 1/3. ))' | ksh

lua

lua -e 'print(1/3)'

or through stdin:

echo 'print(1/3)' | lua

maxima

echo '1/3,numer;' | maxima

with cleaned up output:

echo '1/3,numer;' | maxima --quiet | sed -En '2s/[^ ]+ [^ ]+ +//p'

node

echo 1/3 | node -p

octave

echo 1/3 | octave

perl

echo print 1/3 | perl

python2

echo print 1/3. | python2

python3

echo 'print(1/3)' | python3

R

echo 1/3 | R --no-save

with cleaned up output:

echo 1/3 | R --vanilla --quiet | sed -n '2s/.* //p'

ruby

echo print 1/3.0 | ruby

units

units 1/3

with compact output:

units --co 1/3

wcalc

echo 1/3 | wcalc

with cleaned up output:

echo 1/3 | wcalc | tr -d ' ' | cut -d= -f2

zsh

print $(( 1/3. ))

or through stdin:

echo 'print $(( 1/3. ))' | zsh

#Other sources

Stéphane Chazelas answered a similar question over on Unix.SX.

What does Visual Studio mean by normalize inconsistent line endings?

Line endings also called newline, end of line (EOL) or line break is a control character or sequence of control characters in a character encoding specification (e.g. ASCII or EBCDIC) that is used to signify the end of a line of text and the start of a new one. Some text editors set/implement this special character when you press the Enter key.

The Carriage Return, Line Feed characters are ASCII representations for the end of a line (EOL). They will end the current line of a string, and start a new one.

However, at the operating system level, they are treated differently:

  • The Carriage Return ("CR") character (ASCII 13\0x0D, \r): Moves the cursor to the beginning of the line without advancing to the next line. This character is used as the new line character in Commodore and Early Macintosh operating systems (Mac OS 9 and earlier).

  • The Line Feed ("LF") character (ASCII 10\0x0A, \n): Moves the cursor down to the next line without returning to the beginning of the line. This character is used as the new line character in Unix based systems (Linux, macOS X, Android, etc).

  • The Carriage Return Line Feed ("CRLF") character (0x0D0A, \r\n): This is actually two ASCII characters and is a combination of the CR and LF characters. It moves the cursor both down to the next line and to the beginning of that line. This character is used as the new line character in most other non-Unix operating systems, including Microsoft Windows and Symbian OS.

Normalizing inconsistent line endings in Visual Studio means selecting one character type to be used for all your files. It could be:

  • The Carriage Return Line Feed ("CRLF") character
  • The Line Feed ("LF") character
  • The Carriage Return ("CR") character

However, you can set this in a better way using .gitattributes file in your root directory to avoid conflicts when you move your files from one Operating system to the other.

Simply create a new file called .gitattributes in the root directory of your application:

touch .gitattributes

And add the following in it:

# Enforce Unix newlines
* text=auto eol=lf

This enforces the Unix line feed line ending character.

Note: If this is an already existing project, simply run this command to update the files for the application using the newly defined line ending as specified in the .gitattributes.

git rm --cached -r .
git reset --hard

That's all.

I hope this helps

What is the best alternative IDE to Visual Studio

If you are looking to try Java, I believe NetBeans is a very, very good IDE. However, for .NET, sure there are alternative IDEs but I don't think it makes much sense to use them unless you are developing on an Open Source platform, in which case SharpDevelop is a good choice and is reasonably mature.

Better way to sum a property value in an array

Just another take, this is what native JavaScript functions Map and Reduce were built for (Map and Reduce are powerhouses in many languages).

var traveler = [{description: 'Senior', Amount: 50},
                {description: 'Senior', Amount: 50},
                {description: 'Adult', Amount: 75},
                {description: 'Child', Amount: 35},
                {description: 'Infant', Amount: 25}];

function amount(item){
  return item.Amount;
}

function sum(prev, next){
  return prev + next;
}

traveler.map(amount).reduce(sum);
// => 235;

// or use arrow functions
traveler.map(item => item.Amount).reduce((prev, next) => prev + next);

Note: by making separate smaller functions we get the ability to use them again.

// Example of reuse.
// Get only Amounts greater than 0;

// Also, while using Javascript, stick with camelCase.
// If you do decide to go against the standards, 
// then maintain your decision with all keys as in...

// { description: 'Senior', Amount: 50 }

// would be

// { Description: 'Senior', Amount: 50 };

var travelers = [{description: 'Senior', amount: 50},
                {description: 'Senior', amount: 50},
                {description: 'Adult', amount: 75},
                {description: 'Child', amount: 35},
                {description: 'Infant', amount: 0 }];

// Directly above Travelers array I changed "Amount" to "amount" to match standards.

function amount(item){
  return item.amount;
}

travelers.filter(amount);
// => [{description: 'Senior', amount: 50},
//     {description: 'Senior', amount: 50},
//     {description: 'Adult', amount: 75},
//     {description: 'Child', amount: 35}];
//     Does not include "Infant" as 0 is falsey.

Simulation of CONNECT BY PRIOR of Oracle in SQL Server

I haven't used connect by prior, but a quick search shows it's used for tree structures. In SQL Server, you use common table expressions to get similar functionality.

append new row to old csv file python

# I like using the codecs opening in a with 
field_names = ['latitude', 'longitude', 'date', 'user', 'text']
with codecs.open(filename,"ab", encoding='utf-8') as logfile:
    logger = csv.DictWriter(logfile, fieldnames=field_names)
    logger.writeheader()

# some more code stuff 

    for video in aList:
        video_result = {}                                     
        video_result['date'] = video['snippet']['publishedAt']
        video_result['user'] = video['id']
        video_result['text'] = video['snippet']['description'].encode('utf8')
        logger.writerow(video_result) 

Static Block in Java

yes, static block is used for initialize the code and it will load at the time JVM start for execution.

static block is used in previous versions of java but in latest version it doesn't work.

How to bind Dataset to DataGridView in windows application

use like this :-

gridview1.DataSource = ds.Tables[0]; <-- Use index or your table name which you want to bind
gridview1.DataBind();

I hope it helps!!

Creating a button in Android Toolbar

ToolBar with Button Tutorial

1 - Add library compatibility inside build.gradle

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:21.0.3'
}

2 - Create a file name color.xml to define the Toolbar colors

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="ColorPrimary">#FF5722</color>
    <color name="ColorPrimaryDark">#E64A19</color>
</resources>

3 - Modify your style.xml file

<resources>     
    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">

        <item name="colorPrimary">@color/ColorPrimary</item>
        <item name="colorPrimaryDark">@color/ColorPrimaryDark</item>
        <!-- Customize your theme here. -->
    </style>     
</resources>

4 - Create a xml file like tool_bar.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar
 xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/colorPrimary"
    android:elevation="4dp" />

5 - Include the Toolbar into your main_activity.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <include
        android:id="@+id/tool_bar"
        layout="@layout/tool_bar" />

    <TextView
        android:layout_below="@+id/tool_bar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="@dimen/TextDimTop"
        android:text="@string/hello_world" />

</RelativeLayout>

6 - Then, put it inside your MainActivity class

package com.example.hp1.materialtoolbar;

import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;

/* When using AppCompat support library                                                             
 * (you need to extend Main Activity to                                                            
 * ActionBarActivity)
 * ActionBarActivity has deprecated, use AppCompatActivity
 */
public class MainActivity extends ActionBarActivity { 
    // Declaring the Toolbar Object
    private Toolbar toolbar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_activity);

        // Attaching the layout to the toolbar object
        toolbar = (Toolbar) findViewById(R.id.tool_bar);
        // Setting toolbar as the ActionBar with setSupportActionBar() call
        setSupportActionBar(toolbar);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

7 - And finally, add your "Button Items" to the menu_main.xml inside of /res/menu/ directory

<?xml version="1.0" encoding="utf-8"?>
   <menu
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        tools:context=".MainActivity">
        <item
            android:id="@+id/action_settings"
            android:orderInCategory="100"
            android:title="@string/action_settings"
            app:showAsAction="never" />
        <item
            android:id="@+id/action_search"
            android:orderInCategory="200"
            android:title="Search"
            android:icon="@drawable/ic_search"
            app:showAsAction="ifRoom"/>                
        <item
            android:id="@+id/action_user"
            android:orderInCategory="300"
            android:title="User"
            android:icon="@drawable/ic_user"
            app:showAsAction="ifRoom" />        
    </menu>

rawQuery(query, selectionArgs)

if your SQL query is this

SELECT id,name,roll FROM student WHERE name='Amit' AND roll='7'

then rawQuery will be

String query="SELECT id, name, roll FROM student WHERE name = ? AND roll = ?";
String[] selectionArgs = {"Amit","7"} 
db.rawQuery(query, selectionArgs);

How to remove line breaks from a file in Java?

Try doing this:

 textValue= textValue.replaceAll("\n", "");
 textValue= textValue.replaceAll("\t", "");
 textValue= textValue.replaceAll("\\n", "");
 textValue= textValue.replaceAll("\\t", "");
 textValue= textValue.replaceAll("\r", "");
 textValue= textValue.replaceAll("\\r", "");
 textValue= textValue.replaceAll("\r\n", "");
 textValue= textValue.replaceAll("\\r\\n", "");

How to disable Django's CSRF validation?

If you want disable it in Global, you can write a custom middleware, like this

from django.utils.deprecation import MiddlewareMixin

class DisableCsrfCheck(MiddlewareMixin):

    def process_request(self, req):
        attr = '_dont_enforce_csrf_checks'
        if not getattr(req, attr, False):
            setattr(req, attr, True)

then add this class youappname.middlewarefilename.DisableCsrfCheck to MIDDLEWARE_CLASSES lists, before django.middleware.csrf.CsrfViewMiddleware

encrypt and decrypt md5

This question is tagged with PHP. But many people are using Laravel framework now. It might help somebody in future. That's why I answering for Laravel. It's more easy to encrypt and decrypt with internal functions.

$string = 'c4ca4238a0b923820dcc';
$encrypted = \Illuminate\Support\Facades\Crypt::encrypt($string);
$decrypted_string = \Illuminate\Support\Facades\Crypt::decrypt($encrypted);

var_dump($string);
var_dump($encrypted);
var_dump($decrypted_string);

Note: Be sure to set a 16, 24, or 32 character random string in the key option of the config/app.php file. Otherwise, encrypted values will not be secure.

But you should not use encrypt and decrypt for authentication. Rather you should use hash make and check.

To store password in database, make hash of password and then save.

$password = Input::get('password_from_user'); 
$hashed = Hash::make($password); // save $hashed value

To verify password, get password stored of account from database

// $user is database object
// $inputs is Input from user
if( \Illuminate\Support\Facades\Hash::check( $inputs['password'], $user['password']) == false) {
  // Password is not matching 
} else {
  // Password is matching 
}

Default value to a parameter while passing by reference in C++

In case of OO... To say that a Given Class has and "Default" means that this Default (value) must declared acondingly an then may be usd as an Default Parameter ex:

class Pagination {
public:
    int currentPage;
    //...
    Pagination() {
        currentPage = 1;
        //...
    }
    // your Default Pagination
    static Pagination& Default() {
        static Pagination pag;
        return pag;
    }
};

On your Method ...

 shared_ptr<vector<Auditoria> > 
 findByFilter(Auditoria& audit, Pagination& pagination = Pagination::Default() ) {

This solutions is quite suitable since in this case, "Global default Pagination" is a single "reference" value. You will also have the power to change default values at runtime like an "gobal-level" configuration ex: user pagination navigation preferences and etc..

How to get the row number from a datatable?

ArrayList check = new ArrayList();            

for (int i = 0; i < oDS.Tables[0].Rows.Count; i++)
{
    int iValue = Convert.ToInt32(oDS.Tables[0].Rows[i][3].ToString());
    check.Add(iValue);

}

Javascript setInterval not working

Try this:

function funcName() {
    alert("test");
}

var run = setInterval(funcName, 10000)

How to generate and manually insert a uniqueidentifier in sql server?

Kindly check Column ApplicationId datatype in Table aspnet_Users , ApplicationId column datatype should be uniqueidentifier .

*Your parameter order is passed wrongly , Parameter @id should be passed as first argument, but in your script it is placed in second argument..*

So error is raised..

Please refere sample script:

DECLARE @id uniqueidentifier
SET @id = NEWID()
Create Table #temp1(AppId uniqueidentifier)

insert into #temp1 values(@id)

Select * from #temp1

Drop Table #temp1

How to retrieve the hash for the current commit in Git?

Perhaps you want an alias so you don't have to remember all the nifty details. After doing one of the below steps, you will be able to simply type:

$ git lastcommit
49c03fc679ab11534e1b4b35687b1225c365c630

Following up on the accepted answer, here are two ways to set this up:

1) Teach git the explicit way by editing the global config (my original answer):

 # open the git config editor
 $ git config --global --edit
 # in the alias section, add
 ...
 [alias]
   lastcommit = rev-parse HEAD
 ...

2) Or if you like a shortcut to teach git a shortcut, as recently commented by Adrien:

$ git config --global alias.lastcommit "rev-parse HEAD"

From here on, use git lastcommit to show the last commit's hash.

MongoDB vs Firebase

Apples and oranges. Firebase is a Backend-as-a-Service containing identity management, realtime data views and a document database. It runs in the cloud.

MongoDB on the other hand is a full fledged database with a rich query language. In principle it runs on your own machine, but there are cloud providers.

If you are looking for the database component only MongoDB is much more mature and feature-rich.

Angularjs $http post file and form data

here is my solution:

_x000D_
_x000D_
// Controller_x000D_
$scope.uploadImg = function( files ) {_x000D_
  $scope.data.avatar = files[0];_x000D_
}_x000D_
_x000D_
$scope.update = function() {_x000D_
  var formData = new FormData();_x000D_
  formData.append('desc', data.desc);_x000D_
  formData.append('avatar', data.avatar);_x000D_
  SomeService.upload( formData );_x000D_
}_x000D_
_x000D_
_x000D_
// Service_x000D_
upload: function( formData ) {_x000D_
  var deferred = $q.defer();_x000D_
  var url = "/upload" ;_x000D_
  _x000D_
  var request = {_x000D_
    "url": url,_x000D_
    "method": "POST",_x000D_
    "data": formData,_x000D_
    "headers": {_x000D_
      'Content-Type' : undefined // important_x000D_
    }_x000D_
  };_x000D_
_x000D_
  console.log(request);_x000D_
_x000D_
  $http(request).success(function(data){_x000D_
    deferred.resolve(data);_x000D_
  }).error(function(error){_x000D_
    deferred.reject(error);_x000D_
  });_x000D_
  return deferred.promise;_x000D_
}_x000D_
_x000D_
_x000D_
// backend use express and multer_x000D_
// a part of the code_x000D_
var multer = require('multer');_x000D_
var storage = multer.diskStorage({_x000D_
  destination: function (req, file, cb) {_x000D_
    cb(null, '../public/img')_x000D_
  },_x000D_
  filename: function (req, file, cb) {_x000D_
    cb(null, file.fieldname + '-' + Date.now() + '.jpg');_x000D_
  }_x000D_
})_x000D_
_x000D_
var upload = multer({ storage: storage })_x000D_
app.post('/upload', upload.single('avatar'), function(req, res, next) {_x000D_
  // do something_x000D_
  console.log(req.body);_x000D_
  res.send(req.body);_x000D_
});
_x000D_
<div>_x000D_
  <input type="file" accept="image/*" onchange="angular.element( this ).scope().uploadImg( this.files )">_x000D_
  <textarea ng-model="data.desc" />_x000D_
  <button type="button" ng-click="update()">Update</button>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Force div element to stay in same place, when page is scrolled

You can do this replacing position:absolute; by position:fixed;.

Check if multiple strings exist in another string

a = ['a', 'b', 'c']
str =  "a123"

a_match = [True for match in a if match in str]

if True in a_match:
  print "some of the strings found in str"
else:
  print "no strings found in str"

How does the stack work in assembly language?

What is Stack? A stack is a type of data structure -- a means of storing information in a computer. When a new object is entered in a stack, it is placed on top of all the previously entered objects. In other words, the stack data structure is just like a stack of cards, papers, credit card mailings, or any other real-world objects you can think of. When removing an object from a stack, the one on top gets removed first. This method is referred to as LIFO (last in, first out).

The term "stack" can also be short for a network protocol stack. In networking, connections between computers are made through a series of smaller connections. These connections, or layers, act like the stack data structure, in that they are built and disposed of in the same way.

Difference between Grunt, NPM and Bower ( package.json vs bower.json )

Update for mid 2016:

The things are changing so fast that if it's late 2017 this answer might not be up to date anymore!

Beginners can quickly get lost in choice of build tools and workflows, but what's most up to date in 2016 is not using Bower, Grunt or Gulp at all! With help of Webpack you can do everything directly in NPM!

Don't get me wrong people use other workflows and I still use GULP in my legacy project(but slowly moving out of it), but this is how it's done in the best companies and developers working in this workflow make a LOT of money!

Look at this template it's a very up-to-date setup consisting of a mixture of the best and the latest technologies: https://github.com/coryhouse/react-slingshot

  • Webpack
  • NPM as a build tool (no Gulp, Grunt or Bower)
  • React with Redux
  • ESLint
  • the list is long. Go and explore!

Your questions:

When I want to add a package (and check in the dependency into git), where does it belong - into package.json or into bower.json

  • Everything belongs in package.json now

  • Dependencies required for build are in "devDependencies" i.e. npm install require-dir --save-dev (--save-dev updates your package.json by adding an entry to devDependencies)

  • Dependencies required for your application during runtime are in "dependencies" i.e. npm install lodash --save (--save updates your package.json by adding an entry to dependencies)

If that is the case, when should I ever install packages explicitly like that without adding them to the file that manages dependencies (apart from installing command line tools globally)?

Always. Just because of comfort. When you add a flag (--save-dev or --save) the file that manages deps (package.json) gets updated automatically. Don't waste time by editing dependencies in it manually. Shortcut for npm install --save-dev package-name is npm i -D package-name and shortcut for npm install --save package-name is npm i -S package-name

How to get JSON from URL in JavaScript?

ES8(2017) try

obj = await (await fetch(url)).json();

_x000D_
_x000D_
async function load() {_x000D_
    let url = 'https://my-json-server.typicode.com/typicode/demo/db';_x000D_
    let obj = await (await fetch(url)).json();_x000D_
    console.log(obj);_x000D_
}_x000D_
_x000D_
load();
_x000D_
_x000D_
_x000D_

you can handle errors by try-catch

_x000D_
_x000D_
async function load() {_x000D_
    let url = 'http://query.yahooapis.com/v1/publ...';_x000D_
    let obj = null;_x000D_
    _x000D_
    try {_x000D_
        obj = await (await fetch(url)).json();_x000D_
    } catch(e) {_x000D_
        console.log('error');_x000D_
    }_x000D_
    _x000D_
    console.log(obj);_x000D_
}_x000D_
_x000D_
load();
_x000D_
_x000D_
_x000D_

How to make connection to Postgres via Node.js

We can also use postgresql-easy. It is built on node-postgres and sqlutil. Note: pg_connection.js & your_handler.js are in the same folder. db.js is in the config folder placed.

pg_connection.js

const PgConnection = require('postgresql-easy');
const dbConfig = require('./config/db');
const pg = new PgConnection(dbConfig);
module.exports = pg;

./config/db.js

module.exports =  {
  database: 'your db',
  host: 'your host',
  port: 'your port',
  user: 'your user',
  password: 'your pwd',
}

your_handler.js

  const pg_conctn = require('./pg_connection');

  pg_conctn.getAll('your table')
    .then(res => {
         doResponseHandlingstuff();
      })
    .catch(e => {
         doErrorHandlingStuff()     
      })

jquery how to catch enter key and change event to tab

$('input').live("keypress", function(e) {
            /* ENTER PRESSED*/
            if (e.keyCode == 13) {
                /* FOCUS ELEMENT */
                var inputs = $(this).parents("form").eq(0).find(":input:visible");
                var idx = inputs.index(this);

                if (idx == inputs.length - 1) {
                    inputs[0].select()
                } else {
                    inputs[idx + 1].focus(); //  handles submit buttons
                    inputs[idx + 1].select();
                }
                return false;
            }
        });

visible input cann't be focused.

Killing a process created with Python's subprocess.Popen()

process.terminate() doesn't work when using shell=True. This answer will help you.

How to use Apple's new San Francisco font on a webpage

Last time tested: March 2018


To address the question

How to use Apple's new San Francisco font on a webpage

font-family: -apple-system, system-ui, BlinkMacSystemFont;

or (even shorter):

font-family: -apple-system, BlinkMacSystemFont;

should suffice.

If you want to default to system font on multiple platforms, though, I'd suggest:

font-family: -apple-system, system-ui, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu;
  • -apple-system — San Francisco in Safari (on Mac OS X and iOS); Neue Helvetica and Lucida Grande on older versions of Mac OS X.
  • system-ui — default UI font on a given platform.
  • BlinkMacSystemFont — equivalent of -apple-system, for Chrome on Mac OS X.
  • "Segoe UI" — Windows (Vista+) and Windows Phone.
  • Roboto — Android (Ice Cream Sandwich (4.0)+) and Chrome OS.
  • Ubuntu — all versions of Ubuntu.

The idea is borrowed from the following issue on github.

You can look up fonts for other OS or older versions of them in this article on css-tricks.

Gunicorn worker timeout error

The Microsoft Azure official documentation for running Flask Apps on Azure App Services (Linux App) states the use of timeout as 600

gunicorn --bind=0.0.0.0 --timeout 600 application:app

https://docs.microsoft.com/en-us/azure/app-service/configure-language-python#flask-app

How to wrap text in textview in Android

Just set layout_with to a definate size, when the text fills the maximum width it will overflow to the next line causing a wrap effect.

<TextView
    android:id="@+id/segmentText"
    android:layout_marginTop="10dp"
    android:layout_below="@+id/segmentHeader"
    android:text="You have the option to record in one go or segments(if you swap options 
    you will loose your current recordings)"
    android:layout_width="300dp"
    android:layout_height="wrap_content"/>

Extracting substrings in Go

This is the simple one to perform substring in Go

package main

import "fmt"

var p = fmt.Println

func main() {

  value := "address;bar"

  // Take substring from index 2 to length of string
  substring := value[2:len(value)]
  p(substring)

}

How to display special characters in PHP

Try This

Input:

<!DOCTYPE html>
<html>
<body>

<?php
$str = "This is some <b>bold</b> text.";
echo htmlspecialchars($str);
?>

<p>Converting &lt; and &gt; into entities are often used to prevent browsers from using it as an HTML element. <br />This can be especially useful to prevent code from running when users have access to display input on your homepage.</p>

</body>
</html>

Output:

This is some <b>bold</b> text.

Converting < and > into entities are often used to prevent browsers from using it as an HTML element. This can be especially useful to prevent code from running when users have access to display input on your homepage.

Display a jpg image on a JPanel

You could use a javax.swing.ImageIcon and add it to a JLabel using setIcon() method, then add the JLabel to the JPanel.

How to get correlation of two vectors in python

The docs indicate that numpy.correlate is not what you are looking for:

numpy.correlate(a, v, mode='valid', old_behavior=False)[source]
  Cross-correlation of two 1-dimensional sequences.
  This function computes the correlation as generally defined in signal processing texts:
     z[k] = sum_n a[n] * conj(v[n+k])
  with a and v sequences being zero-padded where necessary and conj being the conjugate.

Instead, as the other comments suggested, you are looking for a Pearson correlation coefficient. To do this with scipy try:

from scipy.stats.stats import pearsonr   
a = [1,4,6]
b = [1,2,3]   
print pearsonr(a,b)

This gives

(0.99339926779878274, 0.073186395040328034)

You can also use numpy.corrcoef:

import numpy
print numpy.corrcoef(a,b)

This gives:

[[ 1.          0.99339927]
 [ 0.99339927  1.        ]]

How to fill color in a cell in VBA?

Non VBA Solution:

Use Conditional Formatting rule with formula: =ISNA(A1) (to highlight cells with all errors - not only #N/A, use =ISERROR(A1))

enter image description here

VBA Solution:

Your code loops through 50 mln cells. To reduce number of cells, I use .SpecialCells(xlCellTypeFormulas, 16) and .SpecialCells(xlCellTypeConstants, 16)to return only cells with errors (note, I'm using If cell.Text = "#N/A" Then)

Sub ColorCells()
    Dim Data As Range, Data2 As Range, cell As Range
    Dim currentsheet As Worksheet

    Set currentsheet = ActiveWorkbook.Sheets("Comparison")

    With currentsheet.Range("A2:AW" & Rows.Count)
        .Interior.Color = xlNone
        On Error Resume Next
        'select only cells with errors
        Set Data = .SpecialCells(xlCellTypeFormulas, 16)
        Set Data2 = .SpecialCells(xlCellTypeConstants, 16)
        On Error GoTo 0
    End With

    If Not Data2 Is Nothing Then
        If Not Data Is Nothing Then
            Set Data = Union(Data, Data2)
        Else
            Set Data = Data2
        End If
    End If

    If Not Data Is Nothing Then
        For Each cell In Data
            If cell.Text = "#N/A" Then
               cell.Interior.ColorIndex = 4
            End If
        Next
    End If
End Sub

Note, to highlight cells witn any error (not only "#N/A"), replace following code

If Not Data Is Nothing Then
   For Each cell In Data
       If cell.Text = "#N/A" Then
          cell.Interior.ColorIndex = 3
       End If
   Next
End If

with

If Not Data Is Nothing Then Data.Interior.ColorIndex = 3

UPD: (how to add CF rule through VBA)

Sub test()
    With ActiveWorkbook.Sheets("Comparison").Range("A2:AW" & Rows.Count).FormatConditions
        .Delete
        .Add Type:=xlExpression, Formula1:="=ISNA(A1)"
        .Item(1).Interior.ColorIndex = 3
    End With
End Sub

How to get numeric position of alphabets in java?

Convert each character to its ASCII code, subtract the ASCII code for "a" and add 1. I'm deliberately leaving the code as an exercise.

This sounds like homework. If so, please tag it as such.

Also, this won't deal with upper case letters, since you didn't state any requirement to handle them, but if you need to then just lowercase the string before you start.

Oh, and this will only deal with the latin "a" through "z" characters without any accents, etc.

.htaccess or .htpasswd equivalent on IIS?

There isn't a direct 1:1 equivalent.

You can password protect a folder or file using file system permissions. If you are using ASP.Net you can also use some of its built in functions to protect various urls.

If you are trying to port .htaccess files used for url rewriting, check out ISAPI Rewrite: http://www.isapirewrite.com/

Can you change a path without reloading the controller in AngularJS?

If you don't have to use URLs like #/item/{{item.id}}/foo and #/item/{{item.id}}/bar but #/item/{{item.id}}/?foo and #/item/{{item.id}}/?bar instead, you can set up your route for /item/{{item.id}}/ to have reloadOnSearch set to false (https://docs.angularjs.org/api/ngRoute/provider/$routeProvider). That tells AngularJS to not reload the view if the search part of the url changes.

Ways to eliminate switch in code

Use a language that doesn't come with a built-in switch statement. Perl 5 comes to mind.

Seriously though, why would you want to avoid it? And if you have good reason to avoid it, why not simply avoid it then?

How do I paste multi-line bash codes into terminal and run it all at once?

Try putting \ at the end of each line before copying it.

Example:

echo "Hello world" && \
script_b.sh

echo $?

The exit code ($?) is now the full sequence of commands, and not just the last command.

What is the best/simplest way to read in an XML file in Java application?

Depending on your application and the scope of the cfg file, a properties file might be the easiest. Sure it isn't as elegant as xml but it certainly easier.

How to unmount a busy device

Just in case someone has the same pb. :

I couldn't unmount the mount point (here /mnt) of a chroot jail.

Here are the commands I typed to investigate :

$ umount /mnt
umount: /mnt: target is busy.
$ df -h | grep /mnt
/dev/mapper/VGTout-rootFS  4.8G  976M  3.6G  22% /mnt
$ fuser -vm /mnt/
                     USER        PID ACCESS COMMAND
/mnt:                root     kernel mount /mnt
$ lsof +f -- /dev/mapper/VGTout-rootFS
$

As you can notice, even lsof returns nothing.

Then I had the idea to type this :

$ df -ah | grep /mnt
/dev/mapper/VGTout-rootFS  4.8G  976M  3.6G  22% /mnt
dev                        2.9G     0  2.9G   0% /mnt/dev
$ umount /mnt/dev
$ umount /mnt
$ df -ah | grep /mnt
$

Here it was a /mnt/dev bind to /dev that I had created to be able to repair my system inside from the chroot jail.

After umounting it, my pb. is now solved.

Can't Load URL: The domain of this URL isn't included in the app's domains

I had the same issue as you, I figured it out. Facebook now roles some features as plugins. In the left hand side select Products and add product. Then select Facbook Login. Pretty straight forward from there, you'll see all the Oauth options show up.

Auto-refreshing div with jQuery - setTimeout or another method?

Another modification:

function update() {
  $.get("response.php", function(data) {
    $("#some_div").html(data);
    window.setTimeout(update, 10000);
  });
}

The difference with this is that it waits 10 seconds AFTER the ajax call is one. So really the time between refreshes is 10 seconds + length of ajax call. The benefit of this is if your server takes longer than 10 seconds to respond, you don't get two (and eventually, many) simultaneous AJAX calls happening.

Also, if the server fails to respond, it won't keep trying.

I've used a similar method in the past using .ajax to handle even more complex behaviour:

function update() {
  $("#notice_div").html('Loading..'); 
  $.ajax({
    type: 'GET',
    url: 'response.php',
    timeout: 2000,
    success: function(data) {
      $("#some_div").html(data);
      $("#notice_div").html(''); 
      window.setTimeout(update, 10000);
    },
    error: function (XMLHttpRequest, textStatus, errorThrown) {
      $("#notice_div").html('Timeout contacting server..');
      window.setTimeout(update, 60000);
    }
}

This shows a loading message while loading (put an animated gif in there for typical "web 2.0" style). If the server times out (in this case takes longer than 2s) or any other kind of error happens, it shows an error, and it waits for 60 seconds before contacting the server again.

This can be especially beneficial when doing fast updates with a larger number of users, where you don't want everyone to suddenly cripple a lagging server with requests that are all just timing out anyways.

Can I use an image from my local file system as background in HTML?

It seems you can provide just the local image name, assuming it is in the same folder...

It suffices like:

background-image: url("img1.png")

PostgreSQL database default location on Linux

Below query will help to find postgres configuration file.

postgres=# SHOW config_file;
             config_file
-------------------------------------
 /var/lib/pgsql/data/postgresql.conf
(1 row)

[root@node1 usr]# cd /var/lib/pgsql/data/
[root@node1 data]# ls -lrth
total 48K
-rw------- 1 postgres postgres    4 Nov 25 13:58 PG_VERSION
drwx------ 2 postgres postgres    6 Nov 25 13:58 pg_twophase
drwx------ 2 postgres postgres    6 Nov 25 13:58 pg_tblspc
drwx------ 2 postgres postgres    6 Nov 25 13:58 pg_snapshots
drwx------ 2 postgres postgres    6 Nov 25 13:58 pg_serial
drwx------ 4 postgres postgres   36 Nov 25 13:58 pg_multixact
-rw------- 1 postgres postgres  20K Nov 25 13:58 postgresql.conf
-rw------- 1 postgres postgres 1.6K Nov 25 13:58 pg_ident.conf
-rw------- 1 postgres postgres 4.2K Nov 25 13:58 pg_hba.conf
drwx------ 3 postgres postgres   60 Nov 25 13:58 pg_xlog
drwx------ 2 postgres postgres   18 Nov 25 13:58 pg_subtrans
drwx------ 2 postgres postgres   18 Nov 25 13:58 pg_clog
drwx------ 5 postgres postgres   41 Nov 25 13:58 base
-rw------- 1 postgres postgres   92 Nov 25 14:00 postmaster.pid
drwx------ 2 postgres postgres   18 Nov 25 14:00 pg_notify
-rw------- 1 postgres postgres   57 Nov 25 14:00 postmaster.opts
drwx------ 2 postgres postgres   32 Nov 25 14:00 pg_log
drwx------ 2 postgres postgres 4.0K Nov 25 14:00 global
drwx------ 2 postgres postgres   25 Nov 25 14:20 pg_stat_tmp

How to ensure that there is a delay before a service is started in systemd?

The systemd way to do this is to have the process "talk back" when it's setup somehow, like by opening a socket or sending a notification (or a parent script exiting). Which is of course not always straight-forward especially with third party stuff :|

You might be able to do something inline like

ExecStart=/bin/bash -c '/bin/start_cassandra &; do_bash_loop_waiting_for_it_to_come_up_here'

or a script that does the same. Or put do_bash_loop_waiting_for_it_to_come_up_here in an ExecStartPost

Or create a helper .service that waits for it to come up, so the helper service depends on cassandra, and waits for it to come up, then your other process can depend on the helper service.

(May want to increase TimeoutStartSec from the default 90s as well)

How to concat two ArrayLists?

add one ArrayList to second ArrayList as:

Arraylist1.addAll(Arraylist2);

EDIT : if you want to Create new ArrayList from two existing ArrayList then do as:

ArrayList<String> arraylist3=new ArrayList<String>();

arraylist3.addAll(Arraylist1); // add first arraylist

arraylist3.addAll(Arraylist2); // add Second arraylist

Converting a String to DateTime

DateTime.Parse

Syntax:

DateTime.Parse(String value)
DateTime.Parse(String value, IFormatProvider provider)
DateTime.Parse(String value, IFormatProvider provider, DateTypeStyles styles)

Example:

string value = "1 January 2019";
CultureInfo provider = new CultureInfo("en-GB");
DateTime.Parse(value, provider, DateTimeStyles.NoCurrentDateDefault););
  • Value: string representation of date and time.
  • Provider: object which provides culture specific info.
  • Styles: formatting options that customize string parsing for some date and time parsing methods. For instance, AllowWhiteSpaces is a value which helps to ignore all spaces present in string while it parse.

It's also worth remembering DateTime is an object that is stored as number internally in the framework, Format only applies to it when you convert it back to string.

  • Parsing converting a string to the internal number type.

  • Formatting converting the internal numeric value to a readable string.

I recently had an issue where I was trying to convert a DateTime to pass to Linq what I hadn't realised at the time was format is irrelevant when passing DateTime to a Linq Query.

DateTime SearchDate = DateTime.Parse(searchDate);
applicationsUsages = applicationsUsages.Where(x => DbFunctions.TruncateTime(x.dateApplicationSelected) == SearchDate.Date);

Full DateTime Documentation

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

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

A lighter editor would be Visual Code

Alternatives :

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

  2. Virtual machine (VMWare Fusion perhaps)

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

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

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

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

Java difference between FileWriter and BufferedWriter

You are right. Here is how write() method of BufferedWriter looks:

public void write(int c) throws IOException {
    synchronized (lock) {
        ensureOpen();
        if (nextChar >= nChars)
            flushBuffer();
        cb[nextChar++] = (char) c;
    }
}

As you can see it indeed checks whether the buffer is full (if (nextChar >= nChars)) and flushes the buffer. Then it adds new character to buffer (cb[nextChar++] = (char) c;).

Get pandas.read_csv to read empty values as empty string instead of nan

We have a simple argument in Pandas read_csv for this:

Use:

df = pd.read_csv('test.csv', na_filter= False)

Pandas documentation clearly explains how the above argument works.

Link

How to upgrade Angular CLI project?

JJB's answer got me on the right track, but the upgrade didn't go very smoothly. My process is detailed below. Hopefully the process becomes easier in the future and JJB's answer can be used or something even more straightforward.

Solution Details

I have followed the steps captured in JJB's answer to update the angular-cli precisely. However, after running npm install angular-cli was broken. Even trying to do ng version would produce an error. So I couldn't do the ng init command. See error below:

$ ng init
core_1.Version is not a constructor
TypeError: core_1.Version is not a constructor
    at Object.<anonymous> (C:\_git\my-project\code\src\main\frontend\node_modules\@angular\compiler-cli\src\version.js:18:19)
    at Module._compile (module.js:556:32)
    at Object.Module._extensions..js (module.js:565:10)
    at Module.load (module.js:473:32)
    ...

To be able to use any angular-cli commands, I had to update my package.json file by hand and bump the @angular dependencies to 2.4.1, then do another npm install.

After this I was able to do ng init. I updated my configuration files, but none of my app/* files. When this was done, I was still getting errors. The first one is detailed below, the second was the same type of error but in a different file.

ERROR in Error encountered resolving symbol values statically. Function calls are not supported. Consider replacing the function or lambda with a reference to an exported function (position 62:9 in the original .ts file), resolving symbol AppModule in C:/_git/my-project/code/src/main/frontend/src/app/app.module.ts

This error is tied to the following factory provider in my AppModule

{ provide: Http, useFactory: 
    (backend: XHRBackend, options: RequestOptions, router: Router, navigationService: NavigationService, errorService: ErrorService) => {
    return new HttpRerouteProvider(backend, options, router, navigationService, errorService);  
  }, deps: [XHRBackend, RequestOptions, Router, NavigationService, ErrorService]
}

To address this error, I had use an exported function and made the following change to the provider.

    { 
      provide: Http, 
      useFactory: httpFactory, 
      deps: [XHRBackend, RequestOptions, Router, NavigationService, ErrorService]
    }

... // elsewhere in AppModule

export function httpFactory(backend: XHRBackend, 
                            options: RequestOptions, 
                            router: Router, 
                            navigationService: NavigationService, 
                            errorService: ErrorService) {
  return new HttpRerouteProvider(backend, options, router, navigationService, errorService);
}

Summary

To summarize what I understand to be the most important details, the following changes were required:

  1. Update angular-cli version using the steps detailed in JJB's answer (and on their github page).

  2. Updating @angular version by hand, 2.0.0 did not seem to be supported by angular-cli version 1.0.0-beta.24

  3. With the assistance of angular-cli and the ng init command, I updated my configuration files. I think the critical changes were to angular-cli.json and package.json. See configuration file changes at the bottom.

  4. Make code changes to export functions before I reference them, as captured in the solution details.

Key Configuration Changes

angular-cli.json changes

{
  "project": {
    "version": "1.0.0-beta.16",
    "name": "frontend"
  },
  "apps": [
    {
      "root": "src",
      "outDir": "dist",
      "assets": "assets",
...

changed to...

{
  "project": {
    "version": "1.0.0-beta.24",
    "name": "frontend"
  },
  "apps": [
    {
      "root": "src",
      "outDir": "dist",
      "assets": [
        "assets",
        "favicon.ico"
      ],
...

My package.json looks like this after a manual merge that considers the versions used by ng-init. Note my angular version is not 2.4.1, but the change I was after was component inheritance which was introduced in 2.3, so I was fine with these versions. The original package.json is in the question.

{
  "name": "frontend",
  "version": "0.0.0",
  "license": "MIT",
  "angular-cli": {},
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "lint": "tslint \"src/**/*.ts\"",
    "test": "ng test",
    "pree2e": "webdriver-manager update --standalone false --gecko false",
    "e2e": "protractor",
    "build": "ng build",
    "buildProd": "ng build --env=prod"
  },
  "private": true,
  "dependencies": {
    "@angular/common": "^2.3.1",
    "@angular/compiler": "^2.3.1",
    "@angular/core": "^2.3.1",
    "@angular/forms": "^2.3.1",
    "@angular/http": "^2.3.1",
    "@angular/platform-browser": "^2.3.1",
    "@angular/platform-browser-dynamic": "^2.3.1",
    "@angular/router": "^3.3.1",
    "@angular/material": "^2.0.0-beta.1",
    "@types/google-libphonenumber": "^7.4.8",
    "angular2-datatable": "^0.4.2",
    "apollo-client": "^0.4.22",
    "core-js": "^2.4.1",
    "rxjs": "^5.0.1",
    "ts-helpers": "^1.1.1",
    "zone.js": "^0.7.2",
    "google-libphonenumber": "^2.0.4",
    "graphql-tag": "^0.1.15",
    "hammerjs": "^2.0.8",
    "ng2-bootstrap": "^1.1.16"
  },
  "devDependencies": {
    "@types/hammerjs": "^2.0.33",
    "@angular/compiler-cli": "^2.3.1",
    "@types/jasmine": "2.5.38",
    "@types/lodash": "^4.14.39",
    "@types/node": "^6.0.42",
    "angular-cli": "1.0.0-beta.24",
    "codelyzer": "~2.0.0-beta.1",
    "jasmine-core": "2.5.2",
    "jasmine-spec-reporter": "2.5.0",
    "karma": "1.2.0",
    "karma-chrome-launcher": "^2.0.0",
    "karma-cli": "^1.0.1",
    "karma-jasmine": "^1.0.2",
    "karma-remap-istanbul": "^0.2.1",
    "protractor": "~4.0.13",
    "ts-node": "1.2.1",
    "tslint": "^4.0.2",
    "typescript": "~2.0.3",
    "typings": "1.4.0"
  }
}

Styling text input caret

In CSS3, there is now a native way to do this, without any of the hacks suggested in the existing answers: the caret-color property.

There are a lot of things you can do to with the caret, as seen below. It can even be animated.

/* Keyword value */
caret-color: auto;
color: transparent;
color: currentColor;

/* <color> values */
caret-color: red;
caret-color: #5729e9;
caret-color: rgb(0, 200, 0);
caret-color: hsla(228, 4%, 24%, 0.8);

The caret-color property is supported from Firefox 55, and Chrome 60. Support is also available in the Safari Technical Preview and in Opera (but not yet in Edge). You can view the current support tables here.

How do I extract the contents of an rpm?

7-zip understands most kinds of archives, including rpm and the included cpio.

How do I set a textbox's text to bold at run time?

The bold property of the font itself is read only, but the actual font property of the text box is not. You can change the font of the textbox to bold as follows:

  textBox1.Font = new Font(textBox1.Font, FontStyle.Bold);

And then back again:

  textBox1.Font = new Font(textBox1.Font, FontStyle.Regular);

Internal Error 500 Apache, but nothing in the logs?

The answers by @eric-leschinski is correct.

But there is another case if your Server API is FPM/FastCGI (Default on Centos 8 or you can check use phpinfo() function)

In this case:

  1. Run phpinfo() in a php file;
  2. Looking for Loaded Configuration File param to see where is config file for your PHP.
  3. Edit config file like @eric-leschinski 's answer.
  4. Check Server API param. If your server only use apache handle API -> restart apache. If your server use php-fpm you must restart php-fpm service

    systemctl restart php-fpm

    Check the log file in php-fpm log folder. eg /var/log/php-fpm/www-error.log

How can I make a horizontal ListView in Android?

After reading this post, I have implemented my own horizontal ListView. You can find it here: http://dev-smart.com/horizontal-listview/ Let me know if this helps.

Refresh an asp.net page on button click

  • Create a class for maintain hit counters

    public static class Counter
    {
           private static long hit;
    
           public static void HitCounter()
           {
              hit++;
           }
    
           public static long GetCounter()
           {
              return hit;
           }
    }
    
  • Increment the value of counter at page load event

    protected void Page_Load(object sender, EventArgs e)
    {
        Counter.HitCounter(); // call static function of static class Counter to increment the counter value
    }
    
  • Redirect the page on itself and display the counter value on button click

    protected void Button1_Click(object sender, EventArgs e)
    {
        Response.Write(Request.RawUrl.ToString()); // redirect on itself
        Response.Write("<br /> Counter =" + Counter.GetCounter() ); // display counter value
    }
    

subtract two times in python

The python timedelta library should do what you need. A timedelta is returned when you subtract two datetime instances.

import datetime
dt_started = datetime.datetime.utcnow()

# do some stuff

dt_ended = datetime.datetime.utcnow()
print((dt_ended - dt_started).total_seconds())

Getting "project" nuget configuration is invalid error

Simply restarting Visual Studio worked for me.

Inheritance and Overriding __init__ in python

In each class that you need to inherit from, you can run a loop of each class that needs init'd upon initiation of the child class...an example that can copied might be better understood...

class Female_Grandparent:
    def __init__(self):
        self.grandma_name = 'Grandma'

class Male_Grandparent:
    def __init__(self):
        self.grandpa_name = 'Grandpa'

class Parent(Female_Grandparent, Male_Grandparent):
    def __init__(self):
        Female_Grandparent.__init__(self)
        Male_Grandparent.__init__(self)

        self.parent_name = 'Parent Class'

class Child(Parent):
    def __init__(self):
        Parent.__init__(self)
#---------------------------------------------------------------------------------------#
        for cls in Parent.__bases__: # This block grabs the classes of the child
             cls.__init__(self)      # class (which is named 'Parent' in this case), 
                                     # and iterates through them, initiating each one.
                                     # The result is that each parent, of each child,
                                     # is automatically handled upon initiation of the 
                                     # dependent class. WOOT WOOT! :D
#---------------------------------------------------------------------------------------#



g = Female_Grandparent()
print g.grandma_name

p = Parent()
print p.grandma_name

child = Child()

print child.grandma_name

Cannot read property 'map' of undefined

The error "Cannot read property 'map' of undefined" will be encountered if there is an error in the "this.props.data" or there is no props.data array.

Better put condition to check the the array like

if(this.props.data){
this.props.data.map(........)
.....
}

Open Bootstrap Modal from code-behind

Maybe this answer is so late, but it's useful.
to do it,we have 3 steps:
1- Create a modal structure in HTML.
2- Create a button to call a function in java script, to open modal and set display:none in CSS .
3- Call this button by function in code behind .
you can see these steps in below snippet :

HTML modal:

<div class="modal fade" id="myModal">
                <div class="modal-dialog">
                    <div class="modal-content">
                        <div class="modal-header">
                            <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                                <span aria-hidden="true">&times;</span></button>
                            <h4 class="modal-title">
                                Registration done Successfully</h4>
                        </div>
                        <div class="modal-body">
                            <asp:Label ID="lblMessage" runat="server" />
                        </div>
                        <div class="modal-footer">
                            <button type="button" class="btn btn-default" data-dismiss="modal">
                                Close</button>
                            <button type="button" class="btn btn-primary">
                                Save changes</button>
                        </div>
                    </div>
                    <!-- /.modal-content -->
                </div>
                <!-- /.modal-dialog -->
            </div>
            <!-- /.modal -->  

Hidden Button:

<button type="button" style="display: none;" id="btnShowPopup" class="btn btn-primary btn-lg"
                data-toggle="modal" data-target="#myModal">
                Launch demo modal
            </button>    

Script Code:

<script type="text/javascript">
        function ShowPopup() {
            $("#btnShowPopup").click();
        }
    </script>  

code behind:

protected void Page_Load(object sender, EventArgs e)
{
    ClientScript.RegisterStartupScript(this.GetType(), "alert", "ShowPopup();", true);
    this.lblMessage.Text = "Your Registration is done successfully. Our team will contact you shotly";
}  

this solution is one of any solutions that I used it .

How to get current user in asp.net core

In addition to existing answers I'd like to add that you can also have a class instance available app-wide which holds user-related data like UserID etc.

It may be useful for refactoring e.g. you don't want to fetch UserID in every controller action and declare an extra UserID parameter in every method related to Service Layer.

I've done a research and here's my post.

You just extend your class which you derive from DbContext by adding UserId property (or implement a custom Session class which has this property).

At filter level you can fetch your class instance and set UserId value.

After that wherever you inject your instance - it will have the necessary data (lifetime must be per request, so you register it using AddScoped method).

Working example:

public class AppInitializationFilter : IAsyncActionFilter
{
    private DBContextWithUserAuditing _dbContext;

    public AppInitializationFilter(
        DBContextWithUserAuditing dbContext
        )
    {
        _dbContext = dbContext;
    }

    public async Task OnActionExecutionAsync(
        ActionExecutingContext context,
        ActionExecutionDelegate next
        )
    {
        string userId = null;
        int? tenantId = null;

        var claimsIdentity = (ClaimsIdentity)context.HttpContext.User.Identity;

        var userIdClaim = claimsIdentity.Claims.SingleOrDefault(c => c.Type == ClaimTypes.NameIdentifier);
        if (userIdClaim != null)
        {
            userId = userIdClaim.Value;
        }

        var tenantIdClaim = claimsIdentity.Claims.SingleOrDefault(c => c.Type == CustomClaims.TenantId);
        if (tenantIdClaim != null)
        {
            tenantId = !string.IsNullOrEmpty(tenantIdClaim.Value) ? int.Parse(tenantIdClaim.Value) : (int?)null;
        }

        _dbContext.UserId = userId;
        _dbContext.TenantId = tenantId;

        var resultContext = await next();
    }
}

For more information see my answer.

html table cell width for different rows

with 5 columns and colspan, this is possible (click here) (but doesn't make much sense to me):

<table width="100%" border="1" bgcolor="#ffffff">
    <colgroup>
        <col width="25%">
        <col width="25%">
        <col width="25%">
        <col width="5%">
        <col width="20%">
    </colgroup>
    <tr>
        <td>25</td>
        <td colspan="2">50</td>
        <td colspan="2">25</td>     
    </tr>
    <tr>
        <td colspan="2">50</td>
        <td colspan="2">30</td>
        <td>20</td>
    </tr>
</table>

Which is the default location for keystore/truststore of Java applications?

Like bruno said, you're better configuring it yourself. Here's how I do it. Start by creating a properties file (/etc/myapp/config.properties).

javax.net.ssl.keyStore = /etc/myapp/keyStore
javax.net.ssl.keyStorePassword = 123456

Then load the properties to your environment from your code. This makes your application configurable.

FileInputStream propFile = new FileInputStream("/etc/myapp/config.properties");
Properties p = new Properties(System.getProperties());
p.load(propFile);
System.setProperties(p);

Allow scroll but hide scrollbar

I know this is an oldie but here is a quick way to hide the scroll bar with pure CSS.

Just add

::-webkit-scrollbar {display:none;}

To your id or class of the div you're using the scroll bar with.

Here is a helpful link Custom Scroll Bar in Webkit

How to set a bitmap from resource

just replace this line

bm = BitmapFactory.decodeResource(null, R.id.image);

with

Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.YourImageName);

I mean to say just change null value with getResources() If you use this code in any button or Image view click event just append getApplicationContext() before getResources()..

Docker is in volume in use, but there aren't any Docker containers

Currently you can use what docker offers now for a general and more complete cleaning:

docker system prune

To additionally remove any stopped containers and all unused images (not just dangling images), add the -a flag to the command:

docker system prune -a

Application.WorksheetFunction.Match method

You are getting this error because the value cannot be found in the range. String or integer doesn't matter. Best thing to do in my experience is to do a check first to see if the value exists.

I used CountIf below, but there is lots of different ways to check existence of a value in a range.

Public Sub test()

Dim rng As Range
Dim aNumber As Long

aNumber = 666

Set rng = Sheet5.Range("B16:B615")

    If Application.WorksheetFunction.CountIf(rng, aNumber) > 0 Then

        rowNum = Application.WorksheetFunction.Match(aNumber, rng, 0)

    Else
        MsgBox aNumber & " does not exist in range " & rng.Address
    End If

End Sub

ALTERNATIVE WAY

Public Sub test()
    Dim rng As Range
    Dim aNumber As Variant
    Dim rowNum As Long

    aNumber = "2gg"

    Set rng = Sheet5.Range("B1:B20")

    If Not IsError(Application.Match(aNumber, rng, 0)) Then
        rowNum = Application.Match(aNumber, rng, 0)
        MsgBox rowNum
    Else
        MsgBox "error"
    End If
End Sub

OR

Public Sub test()
    Dim rng As Range
    Dim aNumber As Variant
    Dim rowNum As Variant

    aNumber = "2gg"

    Set rng = Sheet5.Range("B1:B20")

    rowNum = Application.Match(aNumber, rng, 0)

    If Not IsError(rowNum) Then
        MsgBox rowNum
    Else
        MsgBox "error"
    End If
End Sub

Convert Numeric value to Varchar

i think it should be

select convert(varchar(10),StandardCost) +'S' from DimProduct where ProductKey = 212

or

select cast(StandardCost as varchar(10)) + 'S' from DimProduct where ProductKey = 212

How do you create a yes/no boolean field in SQL server?

You can use the BIT field.

For adding a BIT column to an existing table, the SQL command would look like:

ALTER TABLE table_name ADD yes_no BIT

If you want to create a new table, you could do: CREATE TABLE table_name (yes_no BIT).

.jar error - could not find or load main class

Had this problem couldn't find the answer so i went looking on other threads, I found that i was making my app with 1.8 but for some reason my jre was out dated even though i remember updating it. I downloaded the lastes jre 8 and the jar file runs perfectly. Hope this helps.

Most efficient way to concatenate strings in JavaScript?

Seems based on benchmarks at JSPerf that using += is the fastest method, though not necessarily in every browser.

For building strings in the DOM, it seems to be better to concatenate the string first and then add to the DOM, rather then iteratively add it to the dom. You should benchmark your own case though.

(Thanks @zAlbee for correction)

How to know which version of Symfony I have?

If you want to dynamicallly display your Symfony 2 version in pages, for example in footer, you can do it this way.

Create a service:

<?php

namespace Project\Bundle\DuBundle\Twig;

class SymfonyVersionExtension extends \Twig_Extension
{


 public function getFunctions()
 {
 return array(
 //this is the name of the function you will use in twig
 new \Twig_SimpleFunction('symfony_version', array($this, 'b'))
   );
 }

public function getName()
{
//return 'number_employees';
 return 'symfony_version_extension';
}   

public function b()
{
 $symfony_version = \Symfony\Component\HttpKernel\Kernel::VERSION;
 return $symfony_version;
}
}

Register in service.yml

 dut.twig.symfony_version_extension:
    class: Project\Bundle\DutBundle\Twig\SymfonyVersionExtension
    tags:
        - { name: twig.extension }
    #arguments: []

And you can call it anywhere. In Controller, wrap it in JSON, or in pages example footer

 <p> Built With Symfony {{ symfony_version() }} Version MIT License</p>

Now every time you run composer update to update your vendor, symfony version will also automatically update in your template.I know this is overkill but this is how I do it in my projects and it is working.

Replace Fragment inside a ViewPager

Works Great with AndroidTeam's solution, however I found that I needed the ability to go back much like FrgmentTransaction.addToBackStack(null) But merely adding this will only cause the Fragment to be replaced without notifying the ViewPager. Combining the provided solution with this minor enhancement will allow you to return to the previous state by merely overriding the activity's onBackPressed() method. The biggest drawback is that it will only go back one at a time which may result in multiple back clicks

private ArrayList<Fragment> bFragments = new ArrayList<Fragment>();
private ArrayList<Integer> bPosition = new ArrayList<Integer>();

public void replaceFragmentsWithBackOut(ViewPager container, Fragment oldFragment, Fragment newFragment) {
    startUpdate(container);

    // remove old fragment

    if (mCurTransaction == null) {
         mCurTransaction = mFragmentManager.beginTransaction();
     }
    int position = getFragmentPosition(oldFragment);
     while (mSavedState.size() <= position) {
         mSavedState.add(null);
     }

     //Add Fragment to Back List
     bFragments.add(oldFragment);

     //Add Pager Position to Back List
     bPosition.add(position);

     mSavedState.set(position, null);
     mFragments.set(position, null);

     mCurTransaction.remove(oldFragment);

     // add new fragment

     while (mFragments.size() <= position) {
         mFragments.add(null);
     }
     mFragments.set(position, newFragment);
     mCurTransaction.add(container.getId(), newFragment);

    finishUpdate(container);

    // ensure getItem returns newFragemtn after calling handleGetItemInbalidated()
    handleGetItemInvalidated(container, oldFragment, newFragment);

    container.notifyItemChanged(oldFragment, newFragment);
 }


public boolean popBackImmediate(ViewPager container){
    int bFragSize = bFragments.size();
    int bPosSize = bPosition.size();

    if(bFragSize>0 && bPosSize>0){
        if(bFragSize==bPosSize){
            int last = bFragSize-1;
            int position = bPosition.get(last);

            //Returns Fragment Currently at this position
            Fragment replacedFragment = mFragments.get(position);               
            Fragment originalFragment = bFragments.get(last);

            this.replaceFragments(container, replacedFragment, originalFragment);

            bPosition.remove(last);
            bFragments.remove(last);

            return true;
        }
    }

    return false;       
}

Hope this helps someone.

Also as far as getFragmentPosition() goes it's pretty much getItem() in reverse. You know which fragments go where, just make sure you return the correct position it will be in. Here's an example:

    @Override
    protected int getFragmentPosition(Fragment fragment) {
            if(fragment.equals(originalFragment1)){
                return 0;
            }
            if(fragment.equals(replacementFragment1)){
                return 0;
            }
            if(fragment.equals(Fragment2)){
                return 1;
            }
        return -1;
    }

How to get day of the month?

You could start by reading the documentation for Date. Then you realize that Date’s methods are all deprecated and turn to Calender instead.

Calendar now = Calendar.getInstance();
System.out.println(now.get(Calendar.DAY_OF_MONTH));

Why shouldn't I use PyPy over CPython if PyPy is 6.3 times faster?

NOTE: PyPy is more mature and better supported now than it was in 2013, when this question was asked. Avoid drawing conclusions from out-of-date information.


  1. PyPy, as others have been quick to mention, has tenuous support for C extensions. It has support, but typically at slower-than-Python speeds and it's iffy at best. Hence a lot of modules simply require CPython. PyPy doesn't support numpy. Some extensions are still not supported (Pandas, SciPy, etc.), take a look at the list of supported packages before making the change. Note that many packages marked unsupported on the list are now supported.
  2. Python 3 support is experimental at the moment. has just reached stable! As of 20th June 2014, PyPy3 2.3.1 - Fulcrum is out!
  3. PyPy sometimes isn't actually faster for "scripts", which a lot of people use Python for. These are the short-running programs that do something simple and small. Because PyPy is a JIT compiler its main advantages come from long run times and simple types (such as numbers). PyPy's pre-JIT speeds can be bad compared to CPython.
  4. Inertia. Moving to PyPy often requires retooling, which for some people and organizations is simply too much work.

Those are the main reasons that affect me, I'd say.

Make multiple-select to adjust its height to fit options without scroll bar

You can do this using the size attribute in the select tag. Supposing you have 8 options, then you would do it like:

<select name='courses' multiple="multiple" size='8'>

How to parse a JSON and turn its values into an Array?

You can prefer quick-json parser to meet your requirement...

quick-json parser is very straight forward, flexible, very fast and customizable. Try this out

[quick-json parser] (https://code.google.com/p/quick-json/) - quick-json features -

  • Compliant with JSON specification (RFC4627)

  • High-Performance JSON parser

  • Supports Flexible/Configurable parsing approach

  • Configurable validation of key/value pairs of any JSON Heirarchy

  • Easy to use # Very Less foot print

  • Raises developer friendly and easy to trace exceptions

  • Pluggable Custom Validation support - Keys/Values can be validated by configuring custom validators as and when encountered

  • Validating and Non-Validating parser support

  • Support for two types of configuration (JSON/XML) for using quick-json validating parser

  • Require JDK 1.5 # No dependency on external libraries

  • Support for Json Generation through object serialization

  • Support for collection type selection during parsing process

For e.g.

JsonParserFactory factory=JsonParserFactory.getInstance();
JSONParser parser=factory.newJsonParser();
Map jsonMap=parser.parseJson(jsonString);

OperationalError, no such column. Django

As you went through the tutorial you must have come across the section on migration, as this was one of the major changes in Django 1.7

Prior to Django 1.7, the syncdb command never made any change that had a chance to destroy data currently in the database. This meant that if you did syncdb for a model, then added a new row to the model (a new column, effectively), syncdb would not affect that change in the database.

So either you dropped that table by hand and then ran syncdb again (to recreate it from scratch, losing any data), or you manually entered the correct statements at the database to add only that column.

Then a project came along called south which implemented migrations. This meant that there was a way to migrate forward (and reverse, undo) any changes to the database and preserve the integrity of data.

In Django 1.7, the functionality of south was integrated directly into Django. When working with migrations, the process is a bit different.

  1. Make changes to models.py (as normal).
  2. Create a migration. This generates code to go from the current state to the next state of your model. This is done with the makemigrations command. This command is smart enough to detect what has changed and will create a script to effect that change to your database.
  3. Next, you apply that migration with migrate. This command applies all migrations in order.

So your normal syncdb is now a two-step process, python manage.py makemigrations followed by python manage.py migrate.

Now, on to your specific problem:

class Snippet(models.Model):
    owner = models.ForeignKey('auth.User', related_name='snippets')
    highlighted = models.TextField()
    created = models.DateTimeField(auto_now_add=True)
    title = models.CharField(max_length=100, blank=True, default='')
    code = models.TextField()
    linenos = models.BooleanField(default=False)
    language = models.CharField(choices=LANGUAGE_CHOICES,
                                            default='python',
                                            max_length=100)
    style = models.CharField(choices=STYLE_CHOICES,
                                     default='friendly',
                                     max_length=100)

In this model, you have two fields highlighted and code that is required (they cannot be null).

Had you added these fields from the start, there wouldn't be a problem because the table has no existing rows?

However, if the table has already been created and you add a field that cannot be null, you have to define a default value to provide for any existing rows - otherwise, the database will not accept your changes because they would violate the data integrity constraints.

This is what the command is prompting you about. You can tell Django to apply a default during migration, or you can give it a "blank" default highlighted = models.TextField(default='') in the model itself.

How can I combine two HashMap objects containing the same types?

Method 1: Put maps in a List and then join

public class Test15 {
public static void main(String[] args) {

    Map<String, List<String>> map1 = new HashMap<>();
    map1.put("London", Arrays.asList("A", "B", "C"));
    map1.put("Wales", Arrays.asList("P1", "P2", "P3"));

    Map<String, List<String>> map2 = new HashMap<>();
    map2.put("Calcutta", Arrays.asList("Protijayi", "Gina", "Gini"));
    map2.put("London", Arrays.asList( "P4", "P5", "P6"));
    map2.put("Wales", Arrays.asList( "P111", "P5555", "P677666"));
    
    System.out.println(map1);System.out.println(map2);
    
    
    
    // put the maps in an ArrayList
    
    List<Map<String, List<String>>> maplist = new ArrayList<Map<String,List<String>>>();
    maplist.add(map1);
    maplist.add(map2);
    /*
<T,K,U> Collector<T,?,Map<K,U>> toMap(

                                  Function<? super T,? extends K> keyMapper,

                                  Function<? super T,? extends U> valueMapper,

                                  BinaryOperator<U> mergeFunction)
    */
    
 Map<String, List<String>> collect = maplist.stream()
    .flatMap(ch -> ch.entrySet().stream())
    .collect(
            Collectors.toMap(
            
            //keyMapper,
            
            Entry::getKey,
            
            //valueMapper
            Entry::getValue,
            
            // mergeFunction
     (list_a,list_b) -> Stream.concat(list_a.stream(), list_b.stream()).collect(Collectors.toList())
            
            ));
    
    
    
    System.out.println("Final Result(Map after join) => " + collect);
    /*
    {Wales=[P1, P2, P3], London=[A, B, C]}
{Calcutta=[Protijayi, Gina, Gini], Wales=[P111, P5555, P677666], London=[P4, P5, P6]}
Final Result(Map after join) => {Calcutta=[Protijayi, Gina, Gini], Wales=[P1, P2, P3, P111, P5555, P677666], London=[A, B, C, P4, P5, P6]}
*/
    
}//main


}

Method 2 : Normal Map merge

public class Test15 {
public static void main(String[] args) {

    Map<String, List<String>> map1 = new HashMap<>();
    map1.put("London", Arrays.asList("A", "B", "C"));
    map1.put("Wales", Arrays.asList("P1", "P2", "P3"));

    Map<String, List<String>> map2 = new HashMap<>();
    map2.put("Calcutta", Arrays.asList("Protijayi", "Gina", "Gini"));
    map2.put("London", Arrays.asList( "P4", "P5", "P6"));
    map2.put("Wales", Arrays.asList( "P111", "P5555", "P677666"));
    
    System.out.println(map1);System.out.println(map2);
    
    
    

    /*
<T,K,U> Collector<T,?,Map<K,U>> toMap(

                                  Function<? super T,? extends K> keyMapper,

                                  Function<? super T,? extends U> valueMapper,

                                  BinaryOperator<U> mergeFunction)
    */
    
    
Map<String, List<String>> collect = Stream.of(map1,map2)
    .flatMap(ch -> ch.entrySet().stream())
    .collect(
            Collectors.toMap(
            
            //keyMapper,
            
            Entry::getKey,
            
            //valueMapper
            Entry::getValue,
            
            // mergeFunction
     (list_a,list_b) -> Stream.concat(list_a.stream(), list_b.stream()).collect(Collectors.toList())
            
            ));
    
    
    
    System.out.println("Final Result(Map after join) => " + collect);
    /*
    {Wales=[P1, P2, P3], London=[A, B, C]}
{Calcutta=[Protijayi, Gina, Gini], Wales=[P111, P5555, P677666], London=[P4, P5, P6]}
Final Result(Map after join) => {Calcutta=[Protijayi, Gina, Gini], Wales=[P1, P2, P3, P111, P5555, P677666], London=[A, B, C, P4, P5, P6]}

*/
    
}//main


}
    

In Python, HashMap is called Dictionary and we can merge them very easily.

x = {'Roopa': 1, 'Tabu': 2}
y = {'Roopi': 3, 'Soudipta': 4}


z = {**x,**y}
print(z)
{'Roopa': 1, 'Tabu': 2, 'Roopi': 3, 'Soudipta': 4}

Pretty-Print JSON in Java

Following the JSON-P 1.0 specs (JSR-353) a more current solution for a given JsonStructure (JsonObject or JsonArray) could look like this:

import java.io.StringWriter;
import java.util.HashMap;
import java.util.Map;

import javax.json.Json;
import javax.json.JsonStructure;
import javax.json.JsonWriter;
import javax.json.JsonWriterFactory;
import javax.json.stream.JsonGenerator;

public class PrettyJson {

    private static JsonWriterFactory FACTORY_INSTANCE;

    public static String toString(final JsonStructure status) {

        final StringWriter stringWriter = new StringWriter();

        final JsonWriter jsonWriter = getPrettyJsonWriterFactory()
                .createWriter(stringWriter);

        jsonWriter.write(status);
        jsonWriter.close();

        return stringWriter.toString();
    }

    private static JsonWriterFactory getPrettyJsonWriterFactory() {
        if (null == FACTORY_INSTANCE) {
            final Map<String, Object> properties = new HashMap<>(1);
            properties.put(JsonGenerator.PRETTY_PRINTING, true);
            FACTORY_INSTANCE = Json.createWriterFactory(properties);
        }
        return FACTORY_INSTANCE;
    }

}

Looping Over Result Sets in MySQL

Something like this should do the trick (However, read after the snippet for more info)

CREATE PROCEDURE GetFilteredData()
BEGIN
  DECLARE bDone INT;

  DECLARE var1 CHAR(16);    -- or approriate type
  DECLARE Var2 INT;
  DECLARE Var3 VARCHAR(50);

  DECLARE curs CURSOR FOR  SELECT something FROM somewhere WHERE some stuff;
  DECLARE CONTINUE HANDLER FOR NOT FOUND SET bDone = 1;

  DROP TEMPORARY TABLE IF EXISTS tblResults;
  CREATE TEMPORARY TABLE IF NOT EXISTS tblResults  (
    --Fld1 type,
    --Fld2 type,
    --...
  );

  OPEN curs;

  SET bDone = 0;
  REPEAT
    FETCH curs INTO var1,, b;

    IF whatever_filtering_desired
       -- here for whatever_transformation_may_be_desired
       INSERT INTO tblResults VALUES (var1, var2, var3 ...);
    END IF;
  UNTIL bDone END REPEAT;

  CLOSE curs;
  SELECT * FROM tblResults;
END

A few things to consider...

Concerning the snippet above:

  • may want to pass part of the query to the Stored Procedure, maybe particularly the search criteria, to make it more generic.
  • If this method is to be called by multiple sessions etc. may want to pass a Session ID of sort to create a unique temporary table name (actually unnecessary concern since different sessions do not share the same temporary file namespace; see comment by Gruber, below)
  • A few parts such as the variable declarations, the SELECT query etc. need to be properly specified

More generally: trying to avoid needing a cursor.

I purposely named the cursor variable curs[e], because cursors are a mixed blessing. They can help us implement complicated business rules that may be difficult to express in the declarative form of SQL, but it then brings us to use the procedural (imperative) form of SQL, which is a general feature of SQL which is neither very friendly/expressive, programming-wise, and often less efficient performance-wise.

Maybe you can look into expressing the transformation and filtering desired in the context of a "plain" (declarative) SQL query.

maven "cannot find symbol" message unhelpful

This is not a function of Maven; it's a function of the compiler. Look closely; the information you're looking for is most likely in the following line.

How to add new line in Markdown presentation?

See the original markdown specification (bold mine):

The implication of the “one or more consecutive lines of text” rule is that Markdown supports “hard-wrapped” text paragraphs. This differs significantly from most other text-to-HTML formatters (including Movable Type’s “Convert Line Breaks” option) which translate every line break character in a paragraph into a <br /> tag.

When you do want to insert a <br /> break tag using Markdown, you end a line with two or more spaces, then type return.

How to execute a shell script in PHP?

You might have disabled the exec privileges, most of the LAMP packages have those disabled. Check your php.ini for this line:

disable_functions = exec

And remove the exec, shell_exec entries if there are there.

Good Luck!

lambda expression join multiple tables with select and where clause

I was looking for something and I found this post. I post this code that managed many-to-many relationships in case someone needs it.

    var UserInRole = db.UsersInRoles.Include(u => u.UserProfile).Include(u => u.Roles)
    .Select (m => new 
    {
        UserName = u.UserProfile.UserName,
        RoleName = u.Roles.RoleName
    });

How to create windows service from java jar?

Another option is winsw: https://github.com/kohsuke/winsw/

Configure an xml file to specify the service name, what to execute, any arguments etc. And use the exe to install. Example xml: https://github.com/kohsuke/winsw/tree/master/examples

I prefer this to nssm, because it is one lightweight exe; and the config xml is easy to share/commit to source code.

PS the service is installed by running your-service.exe install

Python list of dictionaries search

You can use a list comprehension:

def search(name, people):
    return [element for element in people if element['name'] == name]

Forward declaration of a typedef in C++

You can do forward typedef. But to do

typedef A B;

you must first forward declare A:

class A;

typedef A B;

How do I test which class an object is in Objective-C?

If you want to check for a specific class then you can use

if([MyClass class] == [myClassObj class]) {
//your object is instance of MyClass
}