Programs & Examples On #Adaptive compression

Cannot use special principal dbo: Error 15405

Fix: Cannot use the special principal ‘sa’. Microsoft SQL Server, Error: 15405

When importing a database in your SQL instance you would find yourself with Cannot use the special principal 'sa'. Microsoft SQL Server, Error: 15405 popping out when setting the sa user as the DBO of the database. To fix this, Open SQL Management Studio and Click New Query. Type:

USE mydatabase
exec sp_changedbowner 'sa', 'true'

Close the new query and after viewing the security of the sa, you will find that that sa is the DBO of the database. (14444)

Source: http://www.noelpulis.com/fix-cannot-use-the-special-principal-sa-microsoft-sql-server-error-15405/

Format string to a 3 digit number

 string.Format("{0:000}", myString);

How to set environment variable or system property in spring tests?

One can also use a test ApplicationContextInitializer to initialize a system property:

public class TestApplicationContextInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext>
{
    @Override
    public void initialize(ConfigurableApplicationContext applicationContext)
    {
        System.setProperty("myproperty", "value");
    }
}

and then configure it on the test class in addition to the Spring context config file locations:

@ContextConfiguration(initializers = TestApplicationContextInitializer.class, locations = "classpath:whereever/context.xml", ...)
@RunWith(SpringJUnit4ClassRunner.class)
public class SomeTest
{
...
}

This way code duplication can be avoided if a certain system property should be set for all the unit tests.

How to check what user php is running as?

If available you can probe the current user account with posix_geteuid and then get the user name with posix_getpwuid.

$username = posix_getpwuid(posix_geteuid())['name'];

If you are running in safe mode however (which is often the case when exec is disabled), then it's unlikely that your PHP process is running under anything but the default www-data or apache account.

Export SQL query data to Excel

I see that you’re trying to export SQL data to Excel to avoid copy-pasting your very large data set into Excel.

You might be interested in learning how to export SQL data to Excel and update the export automatically (with any SQL database: MySQL, Microsoft SQL Server, PostgreSQL).

To export data from SQL to Excel, you need to follow 2 steps:

  • Step 1: Connect Excel to your SQL database? (Microsoft SQL Server, MySQL, PostgreSQL...)
  • Step 2: Import your SQL data into Excel

The result will be the list of tables you want to query data from your SQL database into Excel:

?

Step1: Connect Excel to an external data source: your SQL database

  1. Install An ODBC
  2. Install A Driver
  3. Avoid A Common Error
  4. Create a DSN

Step 2: Import your SQL data into Excel

  1. Click Where You Want Your Pivot Table
  2. Click Insert
  3. Click Pivot Table
  4. Click Use an external data source, then Choose Connection
  5. Click on the System DSN tab
  6. Select the DSN created in ODBC Manager
  7. Fill the requested username and password
  8. Avoid a Common Error
  9. Access The Microsoft Query Dialog Box
  10. Click on the arrow to see the list of tables in your database
  11. Select the table you want to query data from your SQL database into Excel
  12. Click on Return Data when you’re done with your selection

To update the export automatically, there are 2 additional steps:

  1. Create a Pivot Table with an external SQL data source
  2. Automate Your SQL Data Update In Excel With The GETPIVOTDATA Function

I’ve created a step-by-step tutorial about this whole process, from connecting Excel to SQL, up to having the whole thing automatically updated. You might find the detailed explanations and screenshots useful.

Difference between DOMContentLoaded and load events

  • domContentLoaded: marks the point when both the DOM is ready and there are no stylesheets that are blocking JavaScript execution - meaning we can now (potentially) construct the render tree. Many JavaScript frameworks wait for this event before they start executing their own logic. For this reason the browser captures the EventStart and EventEnd timestamps to allow us to track how long this execution took.

  • loadEvent: as a final step in every page load the browser fires an “onload” event which can trigger additional application logic.

source

What's the equivalent of Java's Thread.sleep() in JavaScript?

This eventually helped me:

    var x = 0;
    var buttonText = 'LOADING';

    $('#startbutton').click(function(){
        $(this).text(buttonText);
        window.setTimeout(addDotToButton,2000);
    })

    function addDotToButton(){
        x++;
        buttonText += '.';
        $('#startbutton').text(buttonText);

        if (x < 4) window.setTimeout(addDotToButton, 2000);
        else location.reload(true);
    }

Use URI builder in Android or create URL with variables

here is a good way to explain it:

there are two forms of the URI

1 - Builder(ready to be modified, not ready to be used)

2 - Built(not ready to be modified, ready to be used )

You can create a builder by

Uri.Builder builder = new Uri.Builder();

this gonna return a Builder ready to be modified like this:-

builder.scheme("https");
builder.authority("api.github.com");
builder.appendPath("search");
builder.appendPath("repositories");
builder.appendQueryParameter(PARAMETER_QUERY,parameterValue);

but to use it you have to build it first

retrun builder.build();

or however you gonna use it. and then you have built that is already built for you, ready to use but cannot be modified.

Uri built = Uri.parse("your URI goes here");

this is ready to use but if you want to modify it you need to buildUpon()

Uri built = Uri.parse("Your URI goes here")
           .buildUpon(); //now it's ready to be modified
           .buildUpon()
           .appendQueryParameter(QUERY_PARAMATER, parameterValue) 
           //any modification you want to make goes here
           .build(); // you have to build it back cause you are storing it 
                     // as Uri not Uri.builder

now every time you want to modify it you need to buildUpon() and in the end build().

so Uri.Builder is a Builder type that store a Builder in it. Uri is a Built type that store an already built URI in it.

new Uri.Builder(); rerurns a Builder. Uri.parse("your URI goes here") returns a Built.

and with build() you can change it from Builder to Built. buildUpon() you can change it from Built to Builder. Here is what you can do

Uri.Builder builder = Uri.parse("URL").buildUpon();
// here you created a builder, made an already built URI with Uri.parse
// and then change it to builder with buildUpon();
Uri built = builder.build();
//when you want to change your URI, change Builder 
//when you want to use your URI, use Built

and also the opposite:-

Uri built = new Uri.Builder().build();
// here you created a reference to a built URI
// made a builder with new Uri.Builder() and then change it to a built with 
// built();
Uri.Builder builder = built.buildUpon();

hope my answer helped :) <3

How to "scan" a website (or page) for info, and bring it into my program?

This is referred to as screen scraping, wikipedia has this article on the more specific web scraping. It can be a major challenge because there's some ugly, mess-up, broken-if-not-for-browser-cleverness HTML out there, so good luck.

Why aren't variable-length arrays part of the C++ standard?

This was considered for inclusion in C++/1x, but was dropped (this is a correction to what I said earlier).

It would be less useful in C++ anyway since we already have std::vector to fill this role.

Font Awesome icon inside text input element

You could use a wrapper. Inside the wrapper, add the font awesome element i and the input element.

<div class="wrapper">
    <i class="fa fa-icon"></i>
    <input type="button">
</div>

then set the wrapper's position to relative:

.wrapper { position: relative; }

and then set the i element's position to absolute, and set the correct place for it:

i.fa-icon { position: absolute; top: 10px; left: 50px; }

(It's a hack, I know, but it gets the job done.)

What's the best UML diagramming tool?

I use gmodeler.com. It just does class diagrams.

Good things

  • Very simple feature set. Great UI. Very easy to use.
  • Attractive UI.
  • Don't have to login/create an account
  • Can save diagrams
  • Free

Bad things

  • Hard to collaborate -- have to export to xml (I don't care)
  • Can't access diagrams from any machine because it saves to your browser (I don't care)
  • Can't export as image or pdf (I can take a screen shot)
  • Can't generate code for most languages
  • Very simple feature set. (I don't care)
  • Each class has an 'Event' list which I don't need and I can't get rid of.

How to check if a MySQL query using the legacy API was successful?

put only :

or die(mysqli_error());

after your query

and it will retern the error as echo

example

// "Your Query" means you can put "Select/Update/Delete/Set" queries here
$qfetch = mysqli_fetch_assoc(mysqli_query("your query")) or die(mysqli_error()); 



    if (mysqli_errno()) {
        echo 'error' . mysqli_error();
        die();
    }

What are unit tests, integration tests, smoke tests, and regression tests?

  • Unit test: Specify and test one point of the contract of single method of a class. This should have a very narrow and well defined scope. Complex dependencies and interactions to the outside world are stubbed or mocked.

  • Integration test: Test the correct inter-operation of multiple subsystems. There is whole spectrum there, from testing integration between two classes, to testing integration with the production environment.

  • Smoke test (aka sanity check): A simple integration test where we just check that when the system under test is invoked it returns normally and does not blow up.

    • Smoke testing is both an analogy with electronics, where the first test occurs when powering up a circuit (if it smokes, it's bad!)...
    • ... and, apparently, with plumbing, where a system of pipes is literally filled by smoke and then checked visually. If anything smokes, the system is leaky.
  • Regression test: A test that was written when a bug was fixed. It ensures that this specific bug will not occur again. The full name is "non-regression test". It can also be a test made prior to changing an application to make sure the application provides the same outcome.

To this, I will add:

  • Acceptance test: Test that a feature or use case is correctly implemented. It is similar to an integration test, but with a focus on the use case to provide rather than on the components involved.

  • System test: Tests a system as a black box. Dependencies on other systems are often mocked or stubbed during the test (otherwise it would be more of an integration test).

  • Pre-flight check: Tests that are repeated in a production-like environment, to alleviate the 'builds on my machine' syndrome. Often this is realized by doing an acceptance or smoke test in a production like environment.

Adding system header search path to Xcode

Though this question has an answer, I resolved it differently when I had the same issue. I had this issue when I copied folders with the option Create Folder references; then the above solution of adding the folder to the build_path worked. But when the folder was added using the Create groups for any added folder option, the headers were picked up automatically.

Hibernate SessionFactory vs. JPA EntityManagerFactory

Prefer EntityManagerFactory and EntityManager. They are defined by the JPA standard.

SessionFactory and Session are hibernate-specific. The EntityManager invokes the hibernate session under the hood. And if you need some specific features that are not available in the EntityManager, you can obtain the session by calling:

Session session = entityManager.unwrap(Session.class);

Handling identity columns in an "Insert Into TABLE Values()" statement?

The best practice is to explicitly list the columns:

Insert Into TableName(col1, col2,col2) Values(?, ?, ?)

Otherwise, your original insert will break if you add another column to your table.

How to check existence of user-define table type in SQL Server 2008?

Following examples work for me, please note "is_user_defined" NOT "is_table_type"

IF TYPE_ID(N'idType') IS NULL
CREATE TYPE [dbo].[idType] FROM Bigint NOT NULL
go

IF not EXISTS (SELECT * FROM sys.types WHERE is_user_defined = 1 AND name = 'idType')
CREATE TYPE [dbo].[idType] FROM Bigint NOT NULL
go

How can I analyze a heap dump in IntelliJ? (memory leak)

There also exists a 'JVM Debugger Memory View' found in the plugin repository, which could be useful.

Set form backcolor to custom color

If you want to set the form's back color to some arbitrary RGB value, you can do this:

this.BackColor = Color.FromArgb(255, 232, 232); // this should be pink-ish

How to click an element in Selenium WebDriver using JavaScript

Not sure OP answer was really answered.

var driver = new webdriver.Builder().usingServer('serverAddress').withCapabilities({'browserName': 'firefox'}).build();

driver.get('http://www.google.com');
driver.findElement(webdriver.By.id('gbqfb')).click();

Hashing a string with Sha256

The shortest and fastest way ever. Only 1 line!

public static string StringSha256Hash(string text) =>
    string.IsNullOrEmpty(text) ? string.Empty : BitConverter.ToString(new System.Security.Cryptography.SHA256Managed().ComputeHash(System.Text.Encoding.UTF8.GetBytes(text))).Replace("-", string.Empty);

Get MIME type from filename extension

You could use the table provided from Apache's httpd. It should be trivial to map this into a function, dictionary, list, etc.

Also, as seen here, extension->mime type is not necessarily a function. There may be multiple common MIME types per file extension, so you should look at the requirements of your application, and see why you care about MIME types, what you want "to do" with them, etc. Can you use file extensions to key the same behavior? Do you need to read the first few bytes of a file to determine its MIME type as well?

Pivoting rows into columns dynamically in Oracle

Oracle 11g provides a PIVOT operation that does what you want.

Oracle 11g solution

select * from
(select id, k, v from _kv) 
pivot(max(v) for k in ('name', 'age', 'gender', 'status')

(Note: I do not have a copy of 11g to test this on so I have not verified its functionality)

I obtained this solution from: http://orafaq.com/wiki/PIVOT

EDIT -- pivot xml option (also Oracle 11g)
Apparently there is also a pivot xml option for when you do not know all the possible column headings that you may need. (see the XML TYPE section near the bottom of the page located at http://www.oracle.com/technetwork/articles/sql/11g-pivot-097235.html)

select * from
(select id, k, v from _kv) 
pivot xml (max(v)
for k in (any) )

(Note: As before I do not have a copy of 11g to test this on so I have not verified its functionality)

Edit2: Changed v in the pivot and pivot xml statements to max(v) since it is supposed to be aggregated as mentioned in one of the comments. I also added the in clause which is not optional for pivot. Of course, having to specify the values in the in clause defeats the goal of having a completely dynamic pivot/crosstab query as was the desire of this question's poster.

Set JavaScript variable = null, or leave undefined?

I usually set it to whatever I expect to be returned from the function.

If a string, than i will set it to an empty string ='', same for object ={} and array=[], integers = 0.

using this method saves me the need to check for null / undefined. my function will know how to handle string/array/object regardless of the result.

C# List<string> to string with delimiter

You can also do this with linq if you'd like

var names = new List<string>() { "John", "Anna", "Monica" };
var joinedNames = names.Aggregate((a, b) => a + ", " + b);

Although I prefer the non-linq syntax in Quartermeister's answer and I think Aggregate might perform slower (probably more string concatenation operations).

How do I install a JRE or JDK to run the Android Developer Tools on Windows 7?

The most likely reason why the Java Runtime Environment JRE or Java Development Kit JDK is that it's owned by Oracle not Google and they would need a redistribution agreement which if you know there is some history between the two companies.

Lucky for us that Sun Microsystems before it was bought by Oracle open sourced Java and MySQL a win for us little guys.... Thank you Sun!

Google should probably have a caveat saying you may also need JRE OR JDK

Find size of object instance in bytes in c#

For unmanaged types aka value types, structs:

        Marshal.SizeOf(object);

For managed objects the closer i got is an approximation.

        long start_mem = GC.GetTotalMemory(true);

        aclass[] array = new aclass[1000000];
        for (int n = 0; n < 1000000; n++)
            array[n] = new aclass();

        double used_mem_median = (GC.GetTotalMemory(false) - start_mem)/1000000D;

Do not use serialization.A binary formatter adds headers, so you can change your class and load an old serialized file into the modified class.

Also it won't tell you the real size in memory nor will take into account memory alignment.

[Edit] By using BiteConverter.GetBytes(prop-value) recursivelly on every property of your class you would get the contents in bytes, that doesn't count the weight of the class or references but is much closer to reality. I would recommend to use a byte array for data and an unmanaged proxy class to access values using pointer casting if size matters, note that would be non-aligned memory so on old computers is gonna be slow but HUGE datasets on MODERN RAM is gonna be considerably faster, as minimizing the size to read from RAM is gonna be a bigger impact than unaligned.

MySQL ORDER BY multiple column ASC and DESC

Ok, I THINK I understand what you want now, and let me clarify to confirm before the query. You want 1 record for each user. For each user, you want their BEST POINTS score record. Of the best points per user, you want the one with the best average time. Once you have all users "best" values, you want the final results sorted with best points first... Almost like ranking of a competition.

So now the query. If the above statement is accurate, you need to start with getting the best point/average time per person and assigning a "Rank" to that entry. This is easily done using MySQL @ variables. Then, just include a HAVING clause to only keep those records ranked 1 for each person. Finally apply the order by of best points and shortest average time.

select
      U.UserName,
      PreSortedPerUser.Point,
      PreSortedPerUser.Avg_Time,
      @UserRank := if( @lastUserID = PreSortedPerUser.User_ID, @UserRank +1, 1 ) FinalRank,
      @lastUserID := PreSortedPerUser.User_ID
   from
      ( select
              S.user_id,
              S.point,
              S.avg_time
           from
              Scores S
           order by
              S.user_id,
              S.point DESC,
              S.Avg_Time ) PreSortedPerUser
         JOIN Users U
            on PreSortedPerUser.user_ID = U.ID,
      ( select @lastUserID := 0,
               @UserRank := 0 ) sqlvars 
   having
      FinalRank = 1
   order by
      Point Desc,
      Avg_Time

Results as handled by SQLFiddle

Note, due to the inline @variables needed to get the answer, there are the two extra columns at the end of each row. These are just "left-over" and can be ignored in any actual output presentation you are trying to do... OR, you can wrap the entire thing above one more level to just get the few columns you want like

select 
      PQ.UserName,
      PQ.Point,
      PQ.Avg_Time
   from
      ( entire query above pasted here ) as PQ

Any way (or shortcut) to auto import the classes in IntelliJ IDEA like in Eclipse?

Use control+option+L to auto import the package and auto remove unused packages on Mac

File opens instead of downloading in internet explorer in a href link

This is not a code issue. It is your default IE settings

To change the "always open" setting:

  1. In Windows Explorer, click on the "Tools" menu, choose "Folder options"
  2. In the window that appears, click on the "File Types" tab, and scroll through the list until you find the file extension you want to change (they're in alphabetical order). For example, if Internet Explorer always tries to open .zip files, scroll through the list until you find the entry for "zip".
  3. Click on the file type, then the "Advanced" button.
  4. Check the "Confirm after download" box, then click OK > Close.

EDIT: If you ask me , instead of making any changes in the code i would add the following text "Internet Explorer users: To download file, "Rightclick" the link and hit "Save target as" to download the file."

EDIT 2: THIS solution will work perfectly for you. Its a solution i just copied from the other answer. Im not trying to pass it off as my own

Content-Type: application/octet-stream
Content-Disposition: attachment;filename=\"filename.xxx\"

However you must make sure that you specify the type of file(s) you allow. You have mentioned in your post that you want this for any type of file. This will be an issue.

For ex. If your site has images and if the end user clicks these images then they will be downloaded on his computer instead of opening in a new page. Got the point. So you need to specify the file extensions.

Preferred way to create a Scala list

I always prefer List and I use "fold/reduce" before "for comprehension". However, "for comprehension" is preferred if nested "folds" are required. Recursion is the last resort if I can not accomplish the task using "fold/reduce/for".

so for your example, I will do:

((0 to 3) :\ List[Int]())(_ :: _)

before I do:

(for (x <- 0 to 3) yield x).toList

Note: I use "foldRight(:\)" instead of "foldLeft(/:)" here because of the order of "_"s. For a version that does not throw StackOverflowException, use "foldLeft" instead.

If WorkSheet("wsName") Exists

Slightly changed to David Murdoch's code for generic library

Function HasByName(cSheetName As String, _ 
                   Optional oWorkBook As Excel.Workbook) As Boolean

    HasByName = False
    Dim wb

    If oWorkBook Is Nothing Then
        Set oWorkBook = ThisWorkbook
    End If

    For Each wb In oWorkBook.Worksheets
        If wb.Name = cSheetName Then
            HasByName = True
            Exit Function
        End If
    Next wb
End Function

Is unsigned integer subtraction defined behavior?

The result of a subtraction generating a negative number in an unsigned type is well-defined:

  1. [...] A computation involving unsigned operands can never overflow, because a result that cannot be represented by the resulting unsigned integer type is reduced modulo the number that is one greater than the largest value that can be represented by the resulting type. (ISO/IEC 9899:1999 (E) §6.2.5/9)

As you can see, (unsigned)0 - (unsigned)1 equals -1 modulo UINT_MAX+1, or in other words, UINT_MAX.

Note that although it does say "A computation involving unsigned operands can never overflow", which might lead you to believe that it applies only for exceeding the upper limit, this is presented as a motivation for the actual binding part of the sentence: "a result that cannot be represented by the resulting unsigned integer type is reduced modulo the number that is one greater than the largest value that can be represented by the resulting type." This phrase is not restricted to overflow of the upper bound of the type, and applies equally to values too low to be represented.

How to include "zero" / "0" results in COUNT aggregate?

To change even less on your original query, you can turn your join into a RIGHT join

SELECT person.person_id, COUNT(appointment.person_id) AS "number_of_appointments"
FROM appointment
RIGHT JOIN person ON person.person_id = appointment.person_id
GROUP BY person.person_id;

This just builds on the selected answer, but as the outer join is in the RIGHT direction, only one word needs to be added and less changes. - Just remember that it's there and can sometimes make queries more readable and require less rebuilding.

How to stop a thread created by implementing runnable interface?

If you use ThreadPoolExecutor, and you use submit() method, it will give you a Future back. You can call cancel() on the returned Future to stop your Runnable task.

How to Upload Image file in Retrofit 2

@Multipart
@POST("user/updateprofile")
Observable<ResponseBody> updateProfile(@Part("user_id") RequestBody id,
                                       @Part("full_name") RequestBody fullName,
                                       @Part MultipartBody.Part image,
                                       @Part("other") RequestBody other);

//pass it like this
File file = new File("/storage/emulated/0/Download/Corrections 6.jpg");
RequestBody requestFile =
        RequestBody.create(MediaType.parse("multipart/form-data"), file);

// MultipartBody.Part is used to send also the actual file name
MultipartBody.Part body =
        MultipartBody.Part.createFormData("image", file.getName(), requestFile);

// add another part within the multipart request
RequestBody fullName = 
        RequestBody.create(MediaType.parse("multipart/form-data"), "Your Name");

service.updateProfile(id, fullName, body, other);

Look at the way I am passing the multipart and string params. Hope this will help you!

Generating Random Number In Each Row In Oracle Query

Something like?

select t.*, round(dbms_random.value() * 8) + 1 from foo t;

Edit: David has pointed out this gives uneven distribution for 1 and 9.

As he points out, the following gives a better distribution:

select t.*, floor(dbms_random.value(1, 10)) from foo t;

Submit HTML form, perform javascript function (alert then redirect)

You need to prevent the default behaviour. You can either use e.preventDefault() or return false; In this case, the best thing is, you can use return false; here:

<form onsubmit="completeAndRedirect(); return false;">

document.body.appendChild(i)

If your script is inside head tag in html file, try to put it inside body tag. CreateElement while script is inside head tag will give you a null warning

<head>
  <title></title>
</head>

<body>
  <h1>Game</h1>
  <script type="text/javascript" src="script.js"></script>
</body>

What is the best way to convert seconds into (Hour:Minutes:Seconds:Milliseconds) time?

For .Net <= 4.0 Use the TimeSpan class.

TimeSpan t = TimeSpan.FromSeconds( secs );

string answer = string.Format("{0:D2}h:{1:D2}m:{2:D2}s:{3:D3}ms", 
                t.Hours, 
                t.Minutes, 
                t.Seconds, 
                t.Milliseconds);

(As noted by Inder Kumar Rathore) For .NET > 4.0 you can use

TimeSpan time = TimeSpan.FromSeconds(seconds);

//here backslash is must to tell that colon is
//not the part of format, it just a character that we want in output
string str = time .ToString(@"hh\:mm\:ss\:fff");

(From Nick Molyneux) Ensure that seconds is less than TimeSpan.MaxValue.TotalSeconds to avoid an exception.

Read input numbers separated by spaces

I would recommend reading in the line into a string, then splitting it based on the spaces. For this, you can use the getline(...) function. The trick is having a dynamic sized data structure to hold the strings once it's split. Probably the easiest to use would be a vector.

#include <string>
#include <vector>
...
  string rawInput;
  vector<String> numbers;
  while( getline( cin, rawInput, ' ' ) )
  {
    numbers.push_back(rawInput);
  }

So say the input looks like this:

Enter a number, or numbers separated by a space, between 1 and 1000.
10 5 20 1 200 7

You will now have a vector, numbers, that contains the elements: {"10","5","20","1","200","7"}.

Note that these are still strings, so not useful in arithmetic. To convert them to integers, we use a combination of the STL function, atoi(...), and because atoi requires a c-string instead of a c++ style string, we use the string class' c_str() member function.

while(!numbers.empty())
{
  string temp = numbers.pop_back();//removes the last element from the string
  num = atoi( temp.c_str() ); //re-used your 'num' variable from your code

  ...//do stuff
}

Now there's some problems with this code. Yes, it runs, but it is kind of clunky, and it puts the numbers out in reverse order. Lets re-write it so that it is a little more compact:

#include <string>
...
string rawInput;
cout << "Enter a number, or numbers separated by a space, between 1 and 1000." << endl;
while( getline( cin, rawInput, ' ') )
{
  num = atoi( rawInput.c_str() );
  ...//do your stuff
}

There's still lots of room for improvement with error handling (right now if you enter a non-number the program will crash), and there's infinitely more ways to actually handle the input to get it in a usable number form (the joys of programming!), but that should give you a comprehensive start. :)

Note: I had the reference pages as links, but I cannot post more than two since I have less than 15 posts :/

Edit: I was a little bit wrong about the atoi behavior; I confused it with Java's string->Integer conversions which throw a Not-A-Number exception when given a string that isn't a number, and then crashes the program if the exception isn't handled. atoi(), on the other hand, returns 0, which is not as helpful because what if 0 is the number they entered? Let's make use of the isdigit(...) function. An important thing to note here is that c++ style strings can be accessed like an array, meaning rawInput[0] is the first character in the string all the way up to rawInput[length - 1].

#include <string>
#include <ctype.h>
...
string rawInput;
cout << "Enter a number, or numbers separated by a space, between 1 and 1000." << endl;
while( getline( cin, rawInput, ' ') )
{
  bool isNum = true;
  for(int i = 0; i < rawInput.length() && isNum; ++i)
  {
    isNum = isdigit( rawInput[i]);
  }

  if(isNum)
  {
    num = atoi( rawInput.c_str() );
    ...//do your stuff
  }
  else
    cout << rawInput << " is not a number!" << endl;
}

The boolean (true/false or 1/0 respectively) is used as a flag for the for-loop, which steps through each character in the string and checks to see if it is a 0-9 digit. If any character in the string is not a digit, the loop will break during it's next execution when it gets to the condition "&& isNum" (assuming you've covered loops already). Then after the loop, isNum is used to determine whether to do your stuff, or to print the error message.

Where does the iPhone Simulator store its data?

Where Xcode stores simulators in 2019+ Catalina, Xcode 11.0

Runtimes

$ open ~/Library/Developer/CoreSimulator/Profiles/Runtimes

For example: iOS 13.0, watchOS 6.0 These take the most space, by far. Each one can be up to ~5GB

Devices

$ open ~/Library/Developer/CoreSimulator/Devices

For example: iPhone Xr, iPhone 11 Pro Max. These are typically <15 mb each.

Explanation

Simulators are split between runtimes and devices. If you run $ xcrun simctl list you can see an overview, but if you want to find the physical location of these simulators, look in these directories I've shown.

It's totally safe to delete runtimes you don't support. You can reinstall these later if you want.

Node.js check if file exists

You can use fs.stat to check if target is a file or directory and you can use fs.access to check if you can write/read/execute the file. (remember to use path.resolve to get full path for the target)

Documentation:

Full example (TypeScript)

import * as fs from 'fs';
import * as path from 'path';

const targetPath = path.resolve(process.argv[2]);

function statExists(checkPath): Promise<fs.Stats> {
  return new Promise((resolve) => {
    fs.stat(checkPath, (err, result) => {
      if (err) {
        return resolve(undefined);
      }

      return resolve(result);
    });
  });
}

function checkAccess(checkPath: string, mode: number = fs.constants.F_OK): Promise<boolean> {
  return new Promise((resolve) => {
    fs.access(checkPath, mode, (err) => {
      resolve(!err);
    });
  });
}

(async function () {
  const result = await statExists(targetPath);
  const accessResult = await checkAccess(targetPath, fs.constants.F_OK);
  const readResult = await checkAccess(targetPath, fs.constants.R_OK);
  const writeResult = await checkAccess(targetPath, fs.constants.W_OK);
  const executeResult = await checkAccess(targetPath, fs.constants.X_OK);
  const allAccessResult = await checkAccess(targetPath, fs.constants.F_OK | fs.constants.R_OK | fs.constants.W_OK | fs.constants.X_OK);

  if (result) {
    console.group('stat');
    console.log('isFile: ', result.isFile());
    console.log('isDir: ', result.isDirectory());
    console.groupEnd();
  }
  else {
    console.log('file/dir does not exist');
  }

  console.group('access');
  console.log('access:', accessResult);
  console.log('read access:', readResult);
  console.log('write access:', writeResult);
  console.log('execute access:', executeResult);
  console.log('all (combined) access:', allAccessResult);
  console.groupEnd();

  process.exit(0);
}());

Difference between mkdir() and mkdirs() in java for java.io.File

mkdir()

creates only one directory at a time, if it is parent that one only. other wise it can create the sub directory(if the specified path is existed only) and do not create any directories in between any two directories. so it can not create smultiple directories in one directory

mkdirs()

create the multiple directories(in between two directories also) at a time.

When a 'blur' event occurs, how can I find out which element focus went *to*?

Edit: A hacky way to do it would be to create a variable that keeps track of focus for every element you care about. So, if you care that 'myInput' lost focus, set a variable to it on focus.

<script type="text/javascript">
   var lastFocusedElement;
</script>
<input id="myInput" onFocus="lastFocusedElement=this;" />

Original Answer: You can pass 'this' to the function.

<input id="myInput" onblur="function(this){
   var theId = this.id; // will be 'myInput'
}" />

What are the specific differences between .msi and setup.exe file?

MSI is basically an installer from Microsoft that is built into windows. It associates components with features and contains installation control information. It is not necessary that this file contains actual user required files i.e the application programs which user expects. MSI can contain another setup.exe inside it which the MSI wraps, which actually contains the user required files.

Hope this clears you doubt.

Set style for TextView programmatically

Dynamically changing styles is not supported (yet). You have to set the style before the view gets created, via XML.

How do I restrict a float value to only two places after the decimal point in C?

In C++ (or in C with C-style casts), you could create the function:

/* Function to control # of decimal places to be output for x */
double showDecimals(const double& x, const int& numDecimals) {
    int y=x;
    double z=x-y;
    double m=pow(10,numDecimals);
    double q=z*m;
    double r=round(q);

    return static_cast<double>(y)+(1.0/m)*r;
}

Then std::cout << showDecimals(37.777779,2); would produce: 37.78.

Obviously you don't really need to create all 5 variables in that function, but I leave them there so you can see the logic. There are probably simpler solutions, but this works well for me--especially since it allows me to adjust the number of digits after the decimal place as I need.

CSS3 transform: rotate; in IE9

Standard CSS3 rotate should work in IE9, but I believe you need to give it a vendor prefix, like so:

  -ms-transform: rotate(10deg);

It is possible that it may not work in the beta version; if not, try downloading the current preview version (preview 7), which is a later revision that the beta. I don't have the beta version to test against, so I can't confirm whether it was in that version or not. The final release version is definitely slated to support it.

I can also confirm that the IE-specific filter property has been dropped in IE9.

[Edit]
People have asked for some further documentation. As they say, this is quite limited, but I did find this page: http://css3please.com/ which is useful for testing various CSS3 features in all browsers.

But testing the rotate feature on this page in IE9 preview caused it to crash fairly spectacularly.

However I have done some independant tests using -ms-transform:rotate() in IE9 in my own test pages, and it is working fine. So my conclusion is that the feature is implemented, but has got some bugs, possibly related to setting it dynamically.

Another useful reference point for which features are implemented in which browsers is www.canIuse.com -- see http://caniuse.com/#search=rotation

[EDIT]
Reviving this old answer because I recently found out about a hack called CSS Sandpaper which is relevant to the question and may make things easier.

The hack implements support for the standard CSS transform for for old versions of IE. So now you can add the following to your CSS:

-sand-transform: rotate(10deg);

...and have it work in IE 6/7/8, without having to use the filter syntax. (of course it still uses the filter syntax behind the scenes, but this makes it a lot easier to manage because it's using similar syntax to other browsers)

getActivity() returns null in Fragment function

The order in which the callbacks are called after commit():

  1. Whatever method you call manually right after commit()
  2. onAttach()
  3. onCreateView()
  4. onActivityCreated()

I needed to do some work that involved some Views, so onAttach() didn't work for me; it crashed. So I moved part of my code that was setting some params inside a method called right after commit() (1.), then the other part of the code that handled view inside onCreateView() (3.).

Detect if PHP session exists

I use a combined version:

if(session_id() == '' || !isset($_SESSION)) {
    // session isn't started
    session_start();
}

ALTER TABLE DROP COLUMN failed because one or more objects access this column

As already written in answers you need to drop constraints (created automatically by sql) related to all columns that you are trying to delete.

Perform followings steps to do the needful.

  1. Get Name of all Constraints using sp_helpconstraint which is a system stored procedure utility - execute following exec sp_helpconstraint '<your table name>'
  2. Once you get the name of the constraint then copy that constraint name and execute next statement i.e alter table <your_table_name> drop constraint <constraint_name_that_you_copied_in_1> (It'll be something like this only or similar format)
  3. Once you delete the constraint then you can delete 1 or more columns by using conventional method i.e Alter table <YourTableName> Drop column column1, column2 etc

How to $http Synchronous call with AngularJS

var EmployeeController = ["$scope", "EmployeeService",
        function ($scope, EmployeeService) {
            $scope.Employee = {};
            $scope.Save = function (Employee) {                
                if ($scope.EmployeeForm.$valid) {
                    EmployeeService
                        .Save(Employee)
                        .then(function (response) {
                            if (response.HasError) {
                                $scope.HasError = response.HasError;
                                $scope.ErrorMessage = response.ResponseMessage;
                            } else {

                            }
                        })
                        .catch(function (response) {

                        });
                }
            }
        }]


var EmployeeService = ["$http", "$q",
            function ($http, $q) {
                var self = this;

                self.Save = function (employee) {
                    var deferred = $q.defer();                
                    $http
                        .post("/api/EmployeeApi/Create", angular.toJson(employee))
                        .success(function (response, status, headers, config) {
                            deferred.resolve(response, status, headers, config);
                        })
                        .error(function (response, status, headers, config) {
                            deferred.reject(response, status, headers, config);
                        });

                    return deferred.promise;
                };

inline if statement java, why is not working

Your cases does not have a return value.

getButtons().get(i).setText("§");

In-line-if is Ternary operation all ternary operations must have return value. That variable is likely void and does not return anything and it is not returning to a variable. Example:

int i = 40;
String value = (i < 20) ? "it is too low" : "that is larger than 20";

for your case you just need an if statement.

if (compareChar(curChar, toChar("0"))) { getButtons().get(i).setText("§"); }

Also side note you should use curly braces it makes the code more readable and declares scope.

DateTime "null" value

You can use a nullable DateTime for this.

Nullable<DateTime> myDateTime;

or the same thing written like this:

DateTime? myDateTime;

How to add custom Http Header for C# Web Service Client consuming Axis 1.4 Web service

Instead of modding the auto-generated code or wrapping every call in duplicate code, you can inject your custom HTTP headers by adding a custom message inspector, it's easier than it sounds:

public class CustomMessageInspector : IClientMessageInspector
{
    readonly string _authToken;

    public CustomMessageInspector(string authToken)
    {
        _authToken = authToken;
    }

    public object BeforeSendRequest(ref Message request, IClientChannel channel)
    {
        var reqMsgProperty = new HttpRequestMessageProperty();
        reqMsgProperty.Headers.Add("Auth-Token", _authToken);
        request.Properties[HttpRequestMessageProperty.Name] = reqMsgProperty;
        return null;
    }

    public void AfterReceiveReply(ref Message reply, object correlationState)
    { }
}


public class CustomAuthenticationBehaviour : IEndpointBehavior
{
    readonly string _authToken;

    public CustomAuthenticationBehaviour (string authToken)
    {
        _authToken = authToken;
    }
    public void Validate(ServiceEndpoint endpoint)
    { }

    public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
    { }

    public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
    { }

    public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
    {
        clientRuntime.ClientMessageInspectors.Add(new CustomMessageInspector(_authToken));
    }
}

And when instantiating your client class you can simply add it as a behavior:

this.Endpoint.EndpointBehaviors.Add(new CustomAuthenticationBehaviour("Auth Token"));

This will make every outgoing service call to have your custom HTTP header.

How to quit android application programmatically

Since API 16 you can use the finishAffinity method, which seems to be pretty close to closing all related activities by its name and Javadoc description:

this.finishAffinity();

Finish this activity as well as all activities immediately below it in the current task that have the same affinity. This is typically used when an application can be launched on to another task (such as from an ACTION_VIEW of a content type it understands) and the user has used the up navigation to switch out of the current task and into its own task. In this case, if the user has navigated down into any other activities of the second application, all of those should be removed from the original task as part of the task switch.

Note that this finish does not allow you to deliver results to the previous activity, and an exception will be thrown if you are trying to do so.


Since API 21 you can use a very similar command

finishAndRemoveTask();

Finishes all activities in this task and removes it from the recent tasks list.

DateTime.Compare how to check if a date is less than 30 days old?

Well I would do it like this instead:

TimeSpan diff = expiryDate - DateTime.Today;
if (diff.Days > 30) 
   matchFound = true;

Compare only responds with an integer indicating weather the first is earlier, same or later...

Shortest way to check for null and assign another value if not

To extend @Dave's answer...if planRec.approved_by is already a string

this.approved_by = planRec.approved_by ?? "";

How to import large sql file in phpmyadmin

I have made a PHP script which is designed to import large database dumps which have been generated by phpmyadmin. It's called PETMI and you can download it here [project page] [gitlab page]. It has been tested with a 1GB database.

Change primary key column in SQL Server

Assuming that your current primary key constraint is called pk_history, you can replace the following lines:

ALTER TABLE history ADD PRIMARY KEY (id)

ALTER TABLE history
DROP CONSTRAINT userId
DROP CONSTRAINT name

with these:

ALTER TABLE history DROP CONSTRAINT pk_history

ALTER TABLE history ADD CONSTRAINT pk_history PRIMARY KEY (id)

If you don't know what the name of the PK is, you can find it with the following query:

SELECT * 
  FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS 
 WHERE TABLE_NAME = 'history'

How to add data validation to a cell using VBA

Use this one:

Dim ws As Worksheet
Dim range1 As Range, rng As Range
'change Sheet1 to suit
Set ws = ThisWorkbook.Worksheets("Sheet1")

Set range1 = ws.Range("A1:A5")
Set rng = ws.Range("B1")

With rng.Validation
    .Delete 'delete previous validation
    .Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, _
        Formula1:="='" & ws.Name & "'!" & range1.Address
End With

Note that when you're using Dim range1, rng As range, only rng has type of Range, but range1 is Variant. That's why I'm using Dim range1 As Range, rng As Range.
About meaning of parameters you can read is MSDN, but in short:

  • Type:=xlValidateList means validation type, in that case you should select value from list
  • AlertStyle:=xlValidAlertStop specifies the icon used in message boxes displayed during validation. If user enters any value out of list, he/she would get error message.
  • in your original code, Operator:= xlBetween is odd. It can be used only if two formulas are provided for validation.
  • Formula1:="='" & ws.Name & "'!" & range1.Address for list data validation provides address of list with values (in format =Sheet!A1:A5)

How to stop a looping thread in Python?

Depends on what you run in that thread. If that's your code, then you can implement a stop condition (see other answers).

However, if what you want is to run someone else's code, then you should fork and start a process. Like this:

import multiprocessing
proc = multiprocessing.Process(target=your_proc_function, args=())
proc.start()

now, whenever you want to stop that process, send it a SIGTERM like this:

proc.terminate()
proc.join()

And it's not slow: fractions of a second. Enjoy :)

What do raw.githubusercontent.com URLs represent?

The raw.githubusercontent.com domain is used to serve unprocessed versions of files stored in GitHub repositories. If you browse to a file on GitHub and then click the Raw link, that's where you'll go.

The URL in your question references the install file in the master branch of the Homebrew/install repository. The rest of that command just retrieves the file and runs ruby on its contents.

Convert .cer certificate to .jks

Just to be sure that this is really the "conversion" you need, please note that jks files are keystores, a file format used to store more than one certificate and allows you to retrieve them programmatically using the Java security API, it's not a one-to-one conversion between equivalent formats.

So, if you just want to import that certificate in a new ad-hoc keystore you can do it with Keystore Explorer, a graphical tool. You'll be able to modify the keystore and the certificates contained therein like you would have done with the java terminal utilities like keytool (but in a more accessible way).

VBA array sort function?

I posted some code in answer to a related question on StackOverflow:

Sorting a multidimensionnal array in VBA

The code samples in that thread include:

  1. A vector array Quicksort;
  2. A multi-column array QuickSort;
  3. A BubbleSort.

Alain's optimised Quicksort is very shiny: I just did a basic split-and-recurse, but the code sample above has a 'gating' function that cuts down on redundant comparisons of duplicated values. On the other hand, I code for Excel, and there's a bit more in the way of defensive coding - be warned, you'll need it if your array contains the pernicious 'Empty()' variant, which will break your While... Wend comparison operators and trap your code in an infinite loop.

Note that quicksort algorthms - and any recursive algorithm - can fill the stack and crash Excel. If your array has fewer than 1024 members, I'd use a rudimentary BubbleSort.

Public Sub QuickSortArray(ByRef SortArray As Variant, _
                                Optional lngMin As Long = -1, _ 
                                Optional lngMax As Long = -1, _ 
                                Optional lngColumn As Long = 0)
On Error Resume Next
'Sort a 2-Dimensional array
' Sample Usage: sort arrData by the contents of column 3 ' ' QuickSortArray arrData, , , 3
' 'Posted by Jim Rech 10/20/98 Excel.Programming
'Modifications, Nigel Heffernan:
' ' Escape failed comparison with empty variant ' ' Defensive coding: check inputs
Dim i As Long Dim j As Long Dim varMid As Variant Dim arrRowTemp As Variant Dim lngColTemp As Long

If IsEmpty(SortArray) Then Exit Sub End If
If InStr(TypeName(SortArray), "()") < 1 Then 'IsArray() is somewhat broken: Look for brackets in the type name Exit Sub End If
If lngMin = -1 Then lngMin = LBound(SortArray, 1) End If
If lngMax = -1 Then lngMax = UBound(SortArray, 1) End If
If lngMin >= lngMax Then ' no sorting required Exit Sub End If

i = lngMin j = lngMax
varMid = Empty varMid = SortArray((lngMin + lngMax) \ 2, lngColumn)
' We send 'Empty' and invalid data items to the end of the list: If IsObject(varMid) Then ' note that we don't check isObject(SortArray(n)) - varMid might pick up a valid default member or property i = lngMax j = lngMin ElseIf IsEmpty(varMid) Then i = lngMax j = lngMin ElseIf IsNull(varMid) Then i = lngMax j = lngMin ElseIf varMid = "" Then i = lngMax j = lngMin ElseIf varType(varMid) = vbError Then i = lngMax j = lngMin ElseIf varType(varMid) > 17 Then i = lngMax j = lngMin End If

While i <= j
While SortArray(i, lngColumn) < varMid And i < lngMax i = i + 1 Wend
While varMid < SortArray(j, lngColumn) And j > lngMin j = j - 1 Wend

If i <= j Then
' Swap the rows ReDim arrRowTemp(LBound(SortArray, 2) To UBound(SortArray, 2)) For lngColTemp = LBound(SortArray, 2) To UBound(SortArray, 2) arrRowTemp(lngColTemp) = SortArray(i, lngColTemp) SortArray(i, lngColTemp) = SortArray(j, lngColTemp) SortArray(j, lngColTemp) = arrRowTemp(lngColTemp) Next lngColTemp Erase arrRowTemp
i = i + 1 j = j - 1
End If

Wend
If (lngMin < j) Then Call QuickSortArray(SortArray, lngMin, j, lngColumn) If (i < lngMax) Then Call QuickSortArray(SortArray, i, lngMax, lngColumn)

End Sub

Swift 2: Call can throw, but it is not marked with 'try' and the error is not handled

When calling a function that is declared with throws in Swift, you must annotate the function call site with try or try!. For example, given a throwing function:

func willOnlyThrowIfTrue(value: Bool) throws {
  if value { throw someError }
}

this function can be called like:

func foo(value: Bool) throws {
  try willOnlyThrowIfTrue(value)
}

Here we annotate the call with try, which calls out to the reader that this function may throw an exception, and any following lines of code might not be executed. We also have to annotate this function with throws, because this function could throw an exception (i.e., when willOnlyThrowIfTrue() throws, then foo will automatically rethrow the exception upwards.

If you want to call a function that is declared as possibly throwing, but which you know will not throw in your case because you're giving it correct input, you can use try!.

func bar() {
  try! willOnlyThrowIfTrue(false)
}

This way, when you guarantee that code won't throw, you don't have to put in extra boilerplate code to disable exception propagation.

try! is enforced at runtime: if you use try! and the function does end up throwing, then your program's execution will be terminated with a runtime error.

Most exception handling code should look like the above: either you simply propagate exceptions upward when they occur, or you set up conditions such that otherwise possible exceptions are ruled out. Any clean up of other resources in your code should occur via object destruction (i.e. deinit()), or sometimes via defered code.

func baz(value: Bool) throws {

  var filePath = NSBundle.mainBundle().pathForResource("theFile", ofType:"txt")
  var data = NSData(contentsOfFile:filePath)

  try willOnlyThrowIfTrue(value)

  // data and filePath automatically cleaned up, even when an exception occurs.
}

If for whatever reason you have clean up code that needs to run but isn't in a deinit() function, you can use defer.

func qux(value: Bool) throws {
  defer {
    print("this code runs when the function exits, even when it exits by an exception")
  }

  try willOnlyThrowIfTrue(value)
}

Most code that deals with exceptions simply has them propagate upward to callers, doing cleanup on the way via deinit() or defer. This is because most code doesn't know what to do with errors; it knows what went wrong, but it doesn't have enough information about what some higher level code is trying to do in order to know what to do about the error. It doesn't know if presenting a dialog to the user is appropriate, or if it should retry, or if something else is appropriate.

Higher level code, however, should know exactly what to do in the event of any error. So exceptions allow specific errors to bubble up from where they initially occur to the where they can be handled.

Handling exceptions is done via catch statements.

func quux(value: Bool) {
  do {
    try willOnlyThrowIfTrue(value)
  } catch {
    // handle error
  }
}

You can have multiple catch statements, each catching a different kind of exception.

  do {
    try someFunctionThatThowsDifferentExceptions()
  } catch MyErrorType.errorA {
    // handle errorA
  } catch MyErrorType.errorB {
    // handle errorB
  } catch {
    // handle other errors
  }

For more details on best practices with exceptions, see http://exceptionsafecode.com/. It's specifically aimed at C++, but after examining the Swift exception model, I believe the basics apply to Swift as well.

For details on the Swift syntax and error handling model, see the book The Swift Programming Language (Swift 2 Prerelease).

Practical uses for the "internal" keyword in C#

Another reason to use internal is if you obfuscate your binaries. The obfuscator knows that it's safe to scramble the class name of any internal classes, while the name of public classes can't be scrambled, because that could break existing references.

Entity Framework rollback and remove bad migration

For EF 6 here's a one-liner if you're re-scaffolding a lot in development. Just update the vars and then keep using the up arrow in package manager console to rinse and repeat.

$lastGoodTarget = "OldTargetName"; $newTarget = "NewTargetName"; Update-Database -TargetMigration "$lastGoodTarget" -Verbose; Add-Migration "$newTarget" -Verbose -Force

Why is this necessary you ask? Not sure which versions of EF6 this applies but if your new migration target has already been applied then using '-Force' to re-scaffold in Add-Migration will not actually re-scaffold, but instead make a new file (this is a good thing though because you wouldn't want to lose your 'Down'). The above snippet does the 'Down' first if necessary then -Force works properly to re-scaffold.

MySQL Orderby a number, Nulls last

To achieve following result :

1, 2, 3, 4, NULL, NULL, NULL.

USE syntax, place -(minus sign) before field name and use inverse order_type(Like: If you want order by ASC order then use DESC or if you want DESC order then use ASC)

SELECT * FROM tablename WHERE visible=1 ORDER BY -position DESC

How to change the font size and color of x-axis and y-axis label in a scatterplot with plot function in R?

To track down the correct parameters you need to go first to ?plot.default, which refers you to ?par and ?axis:

plot(1, 1 ,xlab="x axis", ylab="y axis",  pch=19,
           col.lab="red", cex.lab=1.5,    #  for the xlab and ylab
           col="green")                   #  for the points

Enums in Javascript with ES6

Whilst using Symbol as the enum value works fine for simple use cases, it can be handy to give properties to enums. This can be done by using an Object as the enum value containing the properties.

For example we can give each of the Colors a name and hex value:

/**
 * Enum for common colors.
 * @readonly
 * @enum {{name: string, hex: string}}
 */
const Colors = Object.freeze({
  RED:   { name: "red", hex: "#f00" },
  BLUE:  { name: "blue", hex: "#00f" },
  GREEN: { name: "green", hex: "#0f0" }
});

Including properties in the enum avoids having to write switch statements (and possibly forgetting new cases to the switch statements when an enum is extended). The example also shows the enum properties and types documented with the JSDoc enum annotation.

Equality works as expected with Colors.RED === Colors.RED being true, and Colors.RED === Colors.BLUE being false.

Is it possible to get a list of files under a directory of a website? How?

If you have directory listing disabled in your webserver, then the only way somebody will find it is by guessing or by finding a link to it.

That said, I've seen hacking scripts attempt to "guess" a whole bunch of these common names. "secret.html" would probably be in such a guess list.

The more reasonable solution is to restrict access using a username/password via a htaccess file (for apache) or the equivalent setting for whatever webserver you're using.

Select all where [first letter starts with B]

SQL Statement:

 SELECT * FROM employee WHERE employeeName LIKE 'A%';

Result:

Number of Records: 4

employeeID  employeeName    employeeName    Address City    PostalCode  Country

1           Alam             Wipro          Delhi   Delhi   11005      India

2           Aditya           Wipro          Delhi   Delhi   11005      India

3           Alok             HCL            Delhi   Delhi   11005      India

4           Ashok            IBM            Delhi   Delhi   11005      India

'const int' vs. 'int const' as function parameters in C++ and C

const T and T const are identical. With pointer types it becomes more complicated:

  1. const char* is a pointer to a constant char
  2. char const* is a pointer to a constant char
  3. char* const is a constant pointer to a (mutable) char

In other words, (1) and (2) are identical. The only way of making the pointer (rather than the pointee) const is to use a suffix-const.

This is why many people prefer to always put const to the right side of the type (“East const” style): it makes its location relative to the type consistent and easy to remember (it also anecdotally seems to make it easier to teach to beginners).

Regular Expression Validation For Indian Phone Number and Mobile number

you can implement following regex regex = '^[6-9][0-9]{9}$'

Java - Access is denied java.io.FileNotFoundException

You need to set permission for the user controls .

  1. Goto C:\Program Files\
  2. Right click java folder, click properties. Select the security tab.
  3. There, click on "Edit" button, which will pop up PERMISSIONS FOR JAVA window.
  4. Click on Add, which will pop up a new window. In that, in the "Enter object name" box, Enter your user account name, and click okay(if already exist, skip this step).
  5. Now in "PERMISSIONS OF JAVA" window, you will see several clickable options like CREATOR OWNER, SYSTEM, among them is your username. Click on it, and check mark the FULL CONTROL option in Permissions for sub window.
  6. Finally, Hit apply and okay.

<SELECT multiple> - how to allow only one item selected?

Why don't you want to remove the multiple attribute? The entire purpose of that attribute is to specify to the browser that multiple values may be selected from the given select element. If only a single value should be selected, remove the attribute and the browser will know to allow only a single selection.

Use the tools you have, that's what they're for.

Multiple Order By with LINQ

You can use the ThenBy and ThenByDescending extension methods:

foobarList.OrderBy(x => x.Foo).ThenBy( x => x.Bar)

What is callback in Android?

It was discussed before here.

In computer programming, a callback is a piece of executable code that is passed as an argument to other code, which is expected to call back (execute) the argument at some convenient time. The invocation may be immediate as in a synchronous callback or it might happen at later time, as in an asynchronous callback.

Deprecation warning in Moment.js - Not in a recognized ISO format

This answer is to give a better understanding of this warning

Deprecation warning is caused when you use moment to create time object, var today = moment();.

If this warning is okay with you then I have a simpler method.

Don't use date object from js use moment instead. For example use moment() to get the current date.

Or convert the js date object to moment date. You can simply do that specifying the format of your js date object.

ie, moment("js date", "js date format");

eg:

moment("2014 04 25", "YYYY MM DD");

(BUT YOU CAN ONLY USE THIS METHOD UNTIL IT'S DEPRECIATED, this may be depreciated from moment in the future)

Pagination using MySQL LIMIT, OFFSET

If you want to keep it simple go ahead and try this out.

$page_number = mysqli_escape_string($con, $_GET['page']);
$count_per_page = 20;
$next_offset = $page_number * $count_per_page;
$cat =mysqli_query($con, "SELECT * FROM categories LIMIT $count_per_page OFFSET $next_offset");
while ($row = mysqli_fetch_array($cat))
        $count = $row[0];

The rest is up to you. If you have result comming from two tables i suggest you try a different approach.

Java Timer vs ExecutorService?

If it's available to you, then it's difficult to think of a reason not to use the Java 5 executor framework. Calling:

ScheduledExecutorService ex = Executors.newSingleThreadScheduledExecutor();

will give you a ScheduledExecutorService with similar functionality to Timer (i.e. it will be single-threaded) but whose access may be slightly more scalable (under the hood, it uses concurrent structures rather than complete synchronization as with the Timer class). Using a ScheduledExecutorService also gives you advantages such as:

  • You can customize it if need be (see the newScheduledThreadPoolExecutor() or the ScheduledThreadPoolExecutor class)
  • The 'one off' executions can return results

About the only reasons for sticking to Timer I can think of are:

  • It is available pre Java 5
  • A similar class is provided in J2ME, which could make porting your application easier (but it wouldn't be terribly difficult to add a common layer of abstraction in this case)

SQL Query - Concatenating Results into One String

DECLARE @CodeNameString varchar(max)
SET @CodeNameString=''

SELECT @CodeNameString=@CodeNameString+CodeName FROM AccountCodes ORDER BY Sort
SELECT @CodeNameString

How to add element in Python to the end of list using list.insert?

list.insert with any index >= len(of_the_list) places the value at the end of list. It behaves like append

Python 3.7.4
>>>lst=[10,20,30]
>>>lst.insert(len(lst), 101)
>>>lst
[10, 20, 30, 101]
>>>lst.insert(len(lst)+50, 202)
>>>lst
[10, 20, 30, 101, 202]

Time complexity, append O(1), insert O(n)

change cursor to finger pointer

Here is something cool if you want to go the extra mile with this. in the url, you can use a link or save an image png and use the path. for example:

url('assets/imgs/theGoods.png');

below is the code:

.cursor{
  cursor:url(http://www.icon100.com/up/3772/128/425-hand-pointer.png), auto;
}

So this will only work under the size 128 X 128, any bigger and the image wont load. But you can practically use any image you want! This would be consider pure css3, and some html. all you got to do in html is

<div class='cursor'></div>

and only in that div, that cursor will show. So I usually add it to the body tag.

How does one generate a random number in Apple's Swift language?

I use this code to generate a random number:

//
//  FactModel.swift
//  Collection
//
//  Created by Ahmadreza Shamimi on 6/11/16.
//  Copyright © 2016 Ahmadreza Shamimi. All rights reserved.
//

import GameKit

struct FactModel {

    let fun  = ["I love swift","My name is Ahmadreza","I love coding" ,"I love PHP","My name is ALireza","I love Coding too"]


    func getRandomNumber() -> String {

        let randomNumber  = GKRandomSource.sharedRandom().nextIntWithUpperBound(fun.count)

        return fun[randomNumber]
    }
}

Android Studio with Google Play Services

In my case google-play-services_lib are integrate as module (External Libs) for Google map & GCM in my project.

Now, these time require to implement Google Places Autocomplete API but problem is that's code are new and my libs are old so some class not found:

following these steps...

1> Update Google play service into SDK Manager

2> select new .jar file of google play service (Sdk/extras/google/google_play_services/libproject/google-play-services_lib/libs) replace with old one

i got success...!!!

When do I use super()?

I just tried it, commenting super(); does the same thing without commenting it as @Mark Peters said

package javaapplication6;

/**
 *
 * @author sborusu
 */
public class Super_Test {
    Super_Test(){
        System.out.println("This is super class, no object is created");
    }
}
class Super_sub extends Super_Test{
    Super_sub(){
       super();
       System.out.println("This is sub class, object is created");
    }
    public static void main(String args[]){
        new Super_sub();
    }
}

Prevent scroll-bar from adding-up to the Width of page on Chrome

You can get the scrollbar size and then apply a margin to the container.

Something like this:

var checkScrollBars = function(){
    var b = $('body');
    var normalw = 0;
    var scrollw = 0;
    if(b.prop('scrollHeight')>b.height()){
        normalw = window.innerWidth;
        scrollw = normalw - b.width();
        $('#container').css({marginRight:'-'+scrollw+'px'});
    }
}

CSS for remove the h-scrollbar:

body{
    overflow-x:hidden;
}

Try to take a look at this: http://jsfiddle.net/NQAzt/

What does "Could not find or load main class" mean?

In Java, when you sometimes run the JVM from the command line using the java executable and are trying to start a program from a class file with public static void main (PSVM), you might run into the below error even though the classpath parameter to the JVM is accurate and the class file is present on the classpath:

Error: main class not found or loaded

This happens if the class file with PSVM could not be loaded. One possible reason for that is that the class may be implementing an interface or extending another class that is not on the classpath. Normally if a class is not on the classpath, the error thrown indicates as such. But, if the class in use is extended or implemented, java is unable to load the class itself.

Reference: https://www.computingnotes.net/java/error-main-class-not-found-or-loaded/

How do I convert two lists into a dictionary?

Like this:

keys = ['a', 'b', 'c']
values = [1, 2, 3]
dictionary = dict(zip(keys, values))
print(dictionary) # {'a': 1, 'b': 2, 'c': 3}

Voila :-) The pairwise dict constructor and zip function are awesomely useful.

CSS selectors ul li a {...} vs ul > li > a {...}

to answer to your second question - performance IS affected - if you are using those selectors with a single (no nested) ul:

<ul>
    <li>jjj</li>
    <li>jjj</li>    
    <li>jjj</li>
</ul>

the child selector ul > li is more performant than ul li because it is more specific. the browser traverse the dom "right to left", so when it finds a li it then looks for a any ul as a parent in the case of a child selector, while it has to traverse the whole dom tree to find any ul ancestors in case of the descendant selector

How to read the content of a file to a string in C?

I tend to just load the entire buffer as a raw memory chunk into memory and do the parsing on my own. That way I have best control over what the standard lib does on multiple platforms.

This is a stub I use for this. you may also want to check the error-codes for fseek, ftell and fread. (omitted for clarity).

char * buffer = 0;
long length;
FILE * f = fopen (filename, "rb");

if (f)
{
  fseek (f, 0, SEEK_END);
  length = ftell (f);
  fseek (f, 0, SEEK_SET);
  buffer = malloc (length);
  if (buffer)
  {
    fread (buffer, 1, length, f);
  }
  fclose (f);
}

if (buffer)
{
  // start to process your data / extract strings here...
}

Case-insensitive search

If you're just searching for a string rather than a more complicated regular expression, you can use indexOf() - but remember to lowercase both strings first because indexOf() is case sensitive:

var string="Stackoverflow is the BEST"; 
var searchstring="best";

// lowercase both strings
var lcString=string.toLowerCase();
var lcSearchString=searchstring.toLowerCase();

var result = lcString.indexOf(lcSearchString)>=0;
alert(result);

Or in a single line:

var result = string.toLowerCase().indexOf(searchstring.toLowerCase())>=0;

Using Chrome's Element Inspector in Print Preview Mode?

With shortcuts available, the quickest way is to

  1. Open the Developer Tools

    • Windows: F12 or Ctrl+Shift+I
    • Mac: Cmd+Opt+I
  2. Open the Command Menu

    • Windows: Ctrl+Shift+P
    • Mac: Cmd+Shift+P
  3. Type print and select Emulate CSS print media type from the context menu

    Change Media Type Emulation Via Command Menu

Looking at the excellent and currently most-upvoted answer by lmeurs, I think this solution might also remain stable over time.

Is there any standard for JSON API response format?

The RFC 7807: Problem Details for HTTP APIs is at the moment the closest thing we have to an official standard.

Create hyperlink to another sheet

I recorded a macro making a hiperlink. This resulted.

ActiveCell.FormulaR1C1 = "=HYPERLINK(""[Workbook.xlsx]Sheet1!A1"",""CLICK HERE"")"

Pass form data to another page with php

The best way to accomplish that is to use POST which is a method of Hypertext Transfer Protocol https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods

index.php

<html>
<body>

<form action="site2.php" method="post">
Name: <input type="text" name="name">
Email: <input type="text" name="email">
<input type="submit">
</form>

</body>
</html> 

site2.php

 <html>
 <body>

 Hello <?php echo $_POST["name"]; ?>!<br>
 Your mail is <?php echo $_POST["mail"]; ?>.

 </body>
 </html> 

output

Hello "name" !

Your email is "[email protected]" .

How do I push a local Git branch to master branch in the remote?

You can also do it this way to reference the previous branch implicitly:

git checkout mainline
git pull
git merge -
git push

What is the email subject length limit?

See RFC 2822, section 2.1.1 to start.

There are two limits that this standard places on the number of characters in a line. Each line of characters MUST be no more than 998 characters, and SHOULD be no more than 78 characters, excluding the CRLF.

As the RFC states later, you can work around this limit (not that you should) by folding the subject over multiple lines.

Each header field is logically a single line of characters comprising the field name, the colon, and the field body. For convenience however, and to deal with the 998/78 character limitations per line, the field body portion of a header field can be split into a multiple line representation; this is called "folding". The general rule is that wherever this standard allows for folding white space (not simply WSP characters), a CRLF may be inserted before any WSP. For example, the header field:

       Subject: This is a test

can be represented as:

       Subject: This
        is a test

The recommendation for no more than 78 characters in the subject header sounds reasonable. No one wants to scroll to see the entire subject line, and something important might get cut off on the right.

Where is the application.properties file in a Spring Boot project?

In the your first journey in spring boot project I recommend you to start with Spring Starter Try this link here.

enter image description here

It will auto generate the project structure for you like this.application.perperties it will be under /resources.

application.properties important change,

server.port = Your PORT(XXXX) by default=8080
server.servlet.context-path=/api (SpringBoot version 2.x.)
server.contextPath-path=/api (SpringBoot version < 2.x.)

Any way you can use application.yml in case you don't want to make redundancy properties setting.

Example
application.yml

server:
   port: 8080 
   contextPath: /api

application.properties

server.port = 8080
server.contextPath = /api

What is the difference between UTF-8 and ISO-8859-1?

UTF-8 is a multibyte encoding that can represent any Unicode character. ISO 8859-1 is a single-byte encoding that can represent the first 256 Unicode characters. Both encode ASCII exactly the same way.

Passing environment-dependent variables in webpack

I'm not a huge fan of...

new webpack.DefinePlugin({
  'process.env': envVars
}),

...as it does not provides any type of security. instead, you end up boosting your secret stuff, unless you add a webpack to gitignore ??? there is a better solution.

Basically with this config once you compile your code all the process env variables will be removed from the entire code, there is not going to be a single process.env.VAR up thanks to the babel plugin transform-inline-environment-variables PS if you do not want to end up with a whole bunch of undefines, make sure you call the env.js before webpack calls babel-loader, that's why it is the first thing webpack calls. the array of vars in babel.config.js file must match the object on env.js. now there is only one mow thing to do. add a .env file put all your env variables there, the file must be at the root of the project or feel free to add it where ever u want, just make sure to set the same location on the env.js file and also add it to gitignore

const dotFiles = ['.env'].filter(Boolean);

if (existsSync(dotFiles)) {
    require("dotenv-expand")(require("dotenv").config((dotFiles)));
}

If you want to see the whole babel + webpack + ts get it from heaw https://github.com/EnetoJara/Node-typescript-babel-webpack.git

and same logic applies to react and all the other

config
---webpack.js
---env.js
src
---source code world
.env
bunch of dotFiles

env.js

"use strict";
/***
I took the main idea from CRA, but mine is more cooler xD
*/
const {realpathSync, existsSync} = require('fs');
const {resolve, isAbsolute, delimiter} = require('path');

const NODE_ENV = process.env.NODE_ENV || "development";

const appDirectory = realpathSync(process.cwd());

if (typeof NODE_ENV !== "string") {
    throw new Error("falle and stuff");
}

const dotFiles = ['.env'].filter(Boolean);

if (existsSync(dotFiles)) {
    require("dotenv-expand")(require("dotenv").config((dotFiles)));
}

process.env.NODE_PATH = (process.env.NODE_PATH || "")
    .split(delimiter)
    .filter(folder => folder && isAbsolute(folder))
    .map(folder => resolve(appDirectory, folder))
    .join(delimiter);

const ENETO_APP = /^ENETO_APP_/i;

module.exports = (function () {
    const raw = Object.keys ( process.env )
        .filter ( key => ENETO_APP.test ( key ) )
        .reduce ( ( env, key ) => {
                env[ key ] = process.env[ key ];
                return env;
            },
            {
                BABEL_ENV: process.env.ENETO_APP_BABEL_ENV,
                ENETO_APP_DB_NAME: process.env.ENETO_APP_DB_NAME,
                ENETO_APP_DB_PASSWORD: process.env.ENETO_APP_DB_PASSWORD,
                ENETO_APP_DB_USER: process.env.ENETO_APP_DB_USER,
                GENERATE_SOURCEMAP: process.env.ENETO_APP_GENERATE_SOURCEMAP,
                NODE_ENV: process.env.ENETO_APP_NODE_ENV,
                PORT: process.env.ENETO_APP_PORT,
                PUBLIC_URL: "/"
            } );

    const stringyField = {
        "process.env": Object.keys(raw).reduce((env, key)=> {
            env[key]=JSON.stringify(raw[key]);
            return env;
        },{}),

    };

    return {
        raw, stringyField
    }
})();

webpack file with no plugins troll

"use strict";

require("core-js");
require("./env.js");

const path = require("path");
const nodeExternals = require("webpack-node-externals");

module.exports = env => {
    return {
        devtool: "source-map",
        entry: path.join(__dirname, '../src/dev.ts'),
        externals: [nodeExternals()],
        module: {
            rules: [
                {
                    exclude: /node_modules/,
                    test: /\.ts$/,
                    use: [
                        {
                            loader: "babel-loader",
                        },
                        {
                            loader: "ts-loader"
                        }
                    ],
                },
                {
                    test: /\.(png|jpg|gif)$/,
                    use: [
                        {
                            loader: "file-loader",
                        },
                    ],
                },
            ],
        },
        node: {
            __dirname: false,
            __filename: false,
        },
        optimization: {
            splitChunks: {
                automaticNameDelimiter: "_",
                cacheGroups: {
                    vendor: {
                        chunks: "initial",
                        minChunks: 2,
                        name: "vendor",
                        test: /[\\/]node_modules[\\/]/,
                    },
                },
            },
        },
        output: {
            chunkFilename: "main.chunk.js",
            filename: "name-bundle.js",
            libraryTarget: "commonjs2",
        },
        plugins: [],
        resolve: {
            extensions: ['.ts', '.js']
        }   ,
        target: "node"
    };
};

babel.config.js

module.exports = api => {

    api.cache(() => process.env.NODE_ENV);

    return {

        plugins: [
            ["@babel/plugin-proposal-decorators", { legacy: true }],
            ["@babel/plugin-transform-classes", {loose: true}],
            ["@babel/plugin-external-helpers"],
            ["@babel/plugin-transform-runtime"],
            ["@babel/plugin-transform-modules-commonjs"],
            ["transform-member-expression-literals"],
            ["transform-property-literals"],
            ["@babel/plugin-transform-reserved-words"],
            ["@babel/plugin-transform-property-mutators"],
            ["@babel/plugin-transform-arrow-functions"],
            ["@babel/plugin-transform-block-scoped-functions"],
            [
                "@babel/plugin-transform-async-to-generator",
                {
                    method: "coroutine",
                    module: "bluebird",
                },
            ],
            ["@babel/plugin-proposal-async-generator-functions"],
            ["@babel/plugin-transform-block-scoping"],
            ["@babel/plugin-transform-computed-properties"],
            ["@babel/plugin-transform-destructuring"],
            ["@babel/plugin-transform-duplicate-keys"],
            ["@babel/plugin-transform-for-of"],
            ["@babel/plugin-transform-function-name"],
            ["@babel/plugin-transform-literals"],
            ["@babel/plugin-transform-object-super"],
            ["@babel/plugin-transform-shorthand-properties"],
            ["@babel/plugin-transform-spread"],
            ["@babel/plugin-transform-template-literals"],
            ["@babel/plugin-transform-exponentiation-operator"],
            ["@babel/plugin-proposal-object-rest-spread"],
            ["@babel/plugin-proposal-do-expressions"],
            ["@babel/plugin-proposal-export-default-from"],
            ["@babel/plugin-proposal-export-namespace-from"],
            ["@babel/plugin-proposal-logical-assignment-operators"],
            ["@babel/plugin-proposal-throw-expressions"],
            [
                "transform-inline-environment-variables",
                {
                    include: [
                        "ENETO_APP_PORT",
                        "ENETO_APP_NODE_ENV",
                        "ENETO_APP_BABEL_ENV",
                        "ENETO_APP_DB_NAME",
                        "ENETO_APP_DB_USER",
                        "ENETO_APP_DB_PASSWORD",
                    ],
                },
            ],
        ],
        presets: [["@babel/preset-env",{
            targets: {
                node: "current",
                esmodules: true
            },
            useBuiltIns: 'entry',
            corejs: 2,
            modules: "cjs"
        }],"@babel/preset-typescript"],
    };
};

How to check if a std::string is set or not?

I don't think you can tell with the std::string class. However, if you really need this information, you could always derive a class from std::string and give the derived class the ability to tell if it had been changed since construction (or some other arbitrary time). Or better yet, just write a new class that wraps std::string since deriving from std::string may not be a good idea given the lack of a base class virtual destructor. That's probably more work, but more work tends to be needed for an optimal solution.

Of course, you can always just assume if it contains something other than "" then it has been "set", this won't detect it manually getting set to "" though.

how to fix Cannot call sendRedirect() after the response has been committed?

The root cause of IllegalStateException exception is a java servlet is attempting to write to the output stream (response) after the response has been committed.

It is always better to ensure that no content is added to the response after the forward or redirect is done to avoid IllegalStateException. It can be done by including a ‘return’ statement immediately next to the forward or redirect statement.

JAVA 7 OFFICIAL LINK

ADDITIONAL INFO

How to exit an application properly

The following code is used in Visual Basic when prompting a user to exit the application:

Dim D As String

D = MsgBox("Are you sure you want to exit?", vbYesNo+vbQuestion,"Thanking You")

If D =  vbYes Then 
Unload Me
Else
Exit Sub
End If
End
End Sub

replace all occurrences in a string

Use the global flag.

str.replace(/\n/g, '<br />');

What is the best way to check for Internet connectivity using .NET?

Here's how it is implemented in Android.

As a proof of concept, I translated this code to C#:

var request = (HttpWebRequest)WebRequest.Create("http://g.cn/generate_204");
request.UserAgent = "Android";
request.KeepAlive = false;
request.Timeout = 1500;

using (var response = (HttpWebResponse)request.GetResponse())
{
    if (response.ContentLength == 0 && response.StatusCode == HttpStatusCode.NoContent)
    {
        //Connection to internet available
    }
    else
    {
        //Connection to internet not available
    }
}

How to include multiple js files using jQuery $.getScript() method

Append scripts with async=false

Here's a different, but super simple approach. To load multiple scripts you can simply append them to body.

  • Loads them asynchronously, because that's how browsers optimize the page loading
  • Executes scripts in order, because that's how browsers parse the HTML tags
  • No need for callback, because scripts are executed in order. Simply add another script, and it will be executed after the other scripts

More info here: https://www.html5rocks.com/en/tutorials/speed/script-loading/

var scriptsToLoad = [
   "script1.js", 
   "script2.js",
   "script3.js",
]; 
    
scriptsToLoad.forEach(function(src) {
  var script = document.createElement('script');
  script.src = src;
  script.async = false;
  document.body.appendChild(script);
});

How to Verify if file exist with VB script

There is no built-in functionality in VBS for that, however, you can use the FileSystemObject FileExists function for that :

Option Explicit
DIM fso    
Set fso = CreateObject("Scripting.FileSystemObject")

If (fso.FileExists("C:\Program Files\conf")) Then
  WScript.Echo("File exists!")
  WScript.Quit()
Else
  WScript.Echo("File does not exist!")
End If

WScript.Quit()

Disable Input fields in reactive form

The best solution is here:

https://netbasal.com/disabling-form-controls-when-working-with-reactive-forms-in-angular-549dd7b42110

Outline of solution (in case of broken link):

(1) Create a directive

import { NgControl } from '@angular/forms';

@Directive({selector: '[disableControl]'})
export class DisableControlDirective {

  @Input() set disableControl( condition : boolean ) {
    const action = condition ? 'disable' : 'enable';
    this.ngControl.control[action]();
  }

  constructor( private ngControl : NgControl ) {}
}

(2) Use it like so

<input [formControl]="formControl" [disableControl]="condition">

(3) Since disabled inputs do not show in form.value on submit you may need to use the following instead (if required):

onSubmit(form) {
  const formValue = form.getRawValue() // gets form.value including disabled controls
  console.log(formValue)
}

Fixed positioned div within a relative parent div

A simple thing you can do is position your fixed DIV relative to the rest of your page with % values.

Check out this jsfiddle here where the fixed DIV is a sidebar.

div#wrapper {
    margin: auto;
    width: 80%;
}

div#main {
    width: 60%;
}

div#sidebar {
    position: fixed;
    width: 30%;
    left: 60%;
}

And a brief picture below describing the layout above:

example layout

When use ResponseEntity<T> and @RestController for Spring RESTful applications

To complete the answer from Sotorios Delimanolis.

It's true that ResponseEntity gives you more flexibility but in most cases you won't need it and you'll end up with these ResponseEntity everywhere in your controller thus making it difficult to read and understand.

If you want to handle special cases like errors (Not Found, Conflict, etc.), you can add a HandlerExceptionResolver to your Spring configuration. So in your code, you just throw a specific exception (NotFoundException for instance) and decide what to do in your Handler (setting the HTTP status to 404), making the Controller code more clear.

Convert UTC date time to local date time

In my point of view servers should always in the general case return a datetime in the standardized ISO 8601-format.

More info here:

IN this case the server would return '2011-06-29T16:52:48.000Z' which would feed directly into the JS Date object.

var utcDate = '2011-06-29T16:52:48.000Z';  // ISO-8601 formatted date returned from server
var localDate = new Date(utcDate);

The localDate will be in the right local time which in my case would be two hours later (DK time).

You really don't have to do all this parsing which just complicates stuff, as long as you are consistent with what format to expect from the server.

Print series of prime numbers in python

for num in range(1,101):
    prime = True
    for i in range(2,num/2):
        if (num%i==0):
            prime = False
    if prime:
       print num

Java 8 stream's .min() and .max(): why does this compile?

Let me explain what is happening here, because it isn't obvious!

First, Stream.max() accepts an instance of Comparator so that items in the stream can be compared against each other to find the minimum or maximum, in some optimal order that you don't need to worry too much about.

So the question is, of course, why is Integer::max accepted? After all it's not a comparator!

The answer is in the way that the new lambda functionality works in Java 8. It relies on a concept which is informally known as "single abstract method" interfaces, or "SAM" interfaces. The idea is that any interface with one abstract method can be automatically implemented by any lambda - or method reference - whose method signature is a match for the one method on the interface. So examining the Comparator interface (simple version):

public Comparator<T> {
    T compare(T o1, T o2);
}

If a method is looking for a Comparator<Integer>, then it's essentially looking for this signature:

int xxx(Integer o1, Integer o2);

I use "xxx" because the method name is not used for matching purposes.

Therefore, both Integer.min(int a, int b) and Integer.max(int a, int b) are close enough that autoboxing will allow this to appear as a Comparator<Integer> in a method context.

Implements vs extends: When to use? What's the difference?

We use SubClass extends SuperClass only when the subclass wants to use some functionality (methods or instance variables) that is already declared in the SuperClass, or if I want to slightly modify the functionality of the SuperClass (Method overriding). But say, I have an Animal class(SuperClass) and a Dog class (SubClass) and there are few methods that I have defined in the Animal class eg. doEat(); , doSleep(); ... and many more.

Now, my Dog class can simply extend the Animal class, if i want my dog to use any of the methods declared in the Animal class I can invoke those methods by simply creating a Dog object. So this way I can guarantee that I have a dog that can eat and sleep and do whatever else I want the dog to do.

Now, imagine, one day some Cat lover comes into our workspace and she tries to extend the Animal class(cats also eat and sleep). She makes a Cat object and starts invoking the methods.

But, say, someone tries to make an object of the Animal class. You can tell how a cat sleeps, you can tell how a dog eats, you can tell how an elephant drinks. But it does not make any sense in making an object of the Animal class. Because it is a template and we do not want any general way of eating.

So instead, I will prefer to make an abstract class that no one can instantiate but can be used as a template for other classes.

So to conclude, Interface is nothing but an abstract class(a pure abstract class) which contains no method implementations but only the definitions(the templates). So whoever implements the interface just knows that they have the templates of doEat(); and doSleep(); but they have to define their own doEat(); and doSleep(); methods according to their need.

You extend only when you want to reuse some part of the SuperClass(but keep in mind, you can always override the methods of your SuperClass according to your need) and you implement when you want the templates and you want to define them on your own(according to your need).

I will share with you a piece of code: You try it with different sets of inputs and look at the results.

class AnimalClass {

public void doEat() {
    
    System.out.println("Animal Eating...");
}

public void sleep() {
    
    System.out.println("Animal Sleeping...");
}

}

public class Dog extends AnimalClass implements AnimalInterface, Herbi{

public static void main(String[] args) {
    
    AnimalInterface a = new Dog();
    Dog obj = new Dog();
    obj.doEat();
    a.eating();
    
    obj.eating();
    obj.herbiEating();
}

public void doEat() {
    System.out.println("Dog eating...");
}

@Override
public void eating() {
    
    System.out.println("Eating through an interface...");
    // TODO Auto-generated method stub
    
}

@Override
public void herbiEating() {
    
    System.out.println("Herbi eating through an interface...");
    // TODO Auto-generated method stub
    
}


}

Defined Interfaces :

public interface AnimalInterface {

public void eating();

}


interface Herbi {

public void herbiEating();

}

Oracle SQL - REGEXP_LIKE contains characters other than a-z or A-Z

if you want that not contains any of a-z and A-Z:

SELECT * FROM mytable WHERE NOT REGEXP_LIKE(column_1, '[A-Za-z]')

something like:

"98763045098" or "!%436%$7%$*#"

or other languages like persian, arabic and ... like this:

"???? ????"

How to use an output parameter in Java?

You can either use:

  • return X. this will return only one value.

  • return object. will return a full object. For example your object might include X, Y, and Z values.

  • pass array. arrays are passed by reference. i.e. if you pass array of integers, modified the array inside the method, then the original code will see the changes.

Example on passing Array.

void methodOne{
    int [] arr = {1,2,3};
    methodTwo(arr);
    ...//print arr here
}
void methodTwo(int [] arr){
    for (int i=0; i<arr.length;i++){
         arr[i]+=3;
    }
}

This will print out: 4,5,6.

Simplest/cleanest way to implement a singleton in JavaScript

This should work:

function Klass() {
   var instance = this;
   Klass = function () { return instance; }
}

How do you use NSAttributedString?

Since iOS 7 you can use NSAttributedString with HTML syntax:

NSURL *htmlString = [[NSBundle mainBundle]  URLForResource: @"string"     withExtension:@"html"];
NSAttributedString *stringWithHTMLAttributes = [[NSAttributedString alloc] initWithFileURL:htmlString
                                                                                       options:@{NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType}
                                                                            documentAttributes:nil
                                                                                         error:nil];
textView.attributedText = stringWithHTMLAttributes;// you can use a label also

You have to add the file "string.html" to you project, and the content of the html can be like this:

<html>
  <head>
    <style type="text/css">
      body {
        font-size: 15px;
        font-family: Avenir, Arial, sans-serif;
      }
      .red {
        color: red;
      }
      .green {
        color: green;
      }
      .blue {
        color: blue;
      }
    </style>
  </head>
  <body>
    <span class="red">first</span><span class="green">second</span><span class="blue">third</span>
  </body>
</html>  

Now, you can use NSAttributedString as you want, even without HTML file, like for example:

//At the top of your .m file
#define RED_OCCURENCE -red_occurence-
#define GREEN_OCCURENCE -green_occurence-
#define BLUE_OCCURENCE -blue_occurence-
#define HTML_TEMPLATE @"<span style=\"color:red\">-red_occurence-</span><span style=\"color:green\">-green_occurence-</span><span style=\"color:blue\">-blue_occurence-</span></body></html>"

//Where you need to use your attributed string
NSString *string = [HTML_TEMPLATE stringByReplacingOccurrencesOfString:RED_OCCURENCE withString:@"first"] ;
string = [string stringByReplacingOccurrencesOfString:GREEN_OCCURENCE   withString:@"second"];
string = [string stringByReplacingOccurrencesOfString:BLUE_OCCURENCE    withString:@"third"];

NSData* cData = [string dataUsingEncoding:NSUTF8StringEncoding];

NSAttributedString *stringWithHTMLAttributes = [[NSAttributedString alloc] initWithData:cData
                                                                                options:@{NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType}
                                                                        documentAttributes:nil
                                                                                     error:nil];
textView.attributedText = stringWithHTMLAttributes;

Source

Creating a range of dates in Python

Matplotlib related

from matplotlib.dates import drange
import datetime

base = datetime.date.today()
end  = base + datetime.timedelta(days=100)
delta = datetime.timedelta(days=1)
l = drange(base, end, delta)

Opacity of background-color, but not the text

Use rgba!

.alpha60 {
    /* Fallback for web browsers that don't support RGBa */
    background-color: rgb(0, 0, 0);
    /* RGBa with 0.6 opacity */
    background-color: rgba(0, 0, 0, 0.6);
    /* For IE 5.5 - 7*/
    filter:progid:DXImageTransform.Microsoft.gradient(startColorstr=#99000000, endColorstr=#99000000);
    /* For IE 8*/
    -ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr=#99000000, endColorstr=#99000000)";
}

In addition to this, you have to declare background: transparent for IE web browsers, preferably served via conditional comments or similar!

via http://robertnyman.com/2010/01/11/css-background-transparency-without-affecting-child-elements-through-rgba-and-filters/

remove white space from the end of line in linux

Try using

cat kb.txt | sed -e 's/\s$//g'

Finding a branch point with Git?

I seem to be getting some joy with

git rev-list branch...master

The last line you get is the first commit on the branch, so then it's a matter of getting the parent of that. So

git rev-list -1 `git rev-list branch...master | tail -1`^

Seems to work for me and doesn't need diffs and so on (which is helpful as we don't have that version of diff)

Correction: This doesn't work if you are on the master branch, but I'm doing this in a script so that's less of an issue

successful/fail message pop up box after submit?

You are echoing outside the body tag of your HTML. Put your echos there, and you should be fine.

Also, remove the onclick="alert()" from your submit. This is the cause for your first undefined message.

<?php
  $posted = false;
  if( $_POST ) {
    $posted = true;

    // Database stuff here...
    // $result = mysql_query( ... )
    $result = $_POST['name'] == "danny"; // Dummy result
  }
?>

<html>
  <head></head>
  <body>

  <?php
    if( $posted ) {
      if( $result ) 
        echo "<script type='text/javascript'>alert('submitted successfully!')</script>";
      else
        echo "<script type='text/javascript'>alert('failed!')</script>";
    }
  ?>
    <form action="" method="post">
      Name:<input type="text" id="name" name="name"/>
      <input type="submit" value="submit" name="submit"/>
    </form>
  </body>
</html>

Index all *except* one item in python

Use np.delete ! It does not actually delete anything inplace

Example:

import numpy as np
a = np.array([[1,4],[5,7],[3,1]])                                       

# a: array([[1, 4],
#           [5, 7],
#           [3, 1]])

ind = np.array([0,1])                                                   

# ind: array([0, 1])

# a[ind]: array([[1, 4],
#                [5, 7]])

all_except_index = np.delete(a, ind, axis=0)                                              
# all_except_index: array([[3, 1]])

# a: (still the same): array([[1, 4],
#                             [5, 7],
#                             [3, 1]])

How to stretch children to fill cross-axis?

  • The children of a row-flexbox container automatically fill the container's vertical space.

  • Specify flex: 1; for a child if you want it to fill the remaining horizontal space:

_x000D_
_x000D_
.wrapper {_x000D_
  display: flex;_x000D_
  flex-direction: row;_x000D_
  align-items: stretch;_x000D_
  width: 100%;_x000D_
  height: 5em;_x000D_
  background: #ccc;_x000D_
}_x000D_
.wrapper > .left_x000D_
{_x000D_
  background: #fcc;_x000D_
}_x000D_
.wrapper > .right_x000D_
{_x000D_
  background: #ccf;_x000D_
  flex: 1; _x000D_
}
_x000D_
<div class="wrapper">_x000D_
  <div class="left">Left</div>_x000D_
  <div class="right">Right</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

  • Specify flex: 1; for both children if you want them to fill equal amounts of the horizontal space:

_x000D_
_x000D_
.wrapper {_x000D_
  display: flex;_x000D_
  flex-direction: row;_x000D_
  align-items: stretch;_x000D_
  width: 100%;_x000D_
  height: 5em;_x000D_
  background: #ccc;_x000D_
}_x000D_
.wrapper > div _x000D_
{_x000D_
  flex: 1; _x000D_
}_x000D_
.wrapper > .left_x000D_
{_x000D_
  background: #fcc;_x000D_
}_x000D_
.wrapper > .right_x000D_
{_x000D_
  background: #ccf;_x000D_
}
_x000D_
<div class="wrapper">_x000D_
  <div class="left">Left</div>_x000D_
  <div class="right">Right</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Can't accept license agreement Android SDK Platform 24

For me I was Building the Ionic using "ionic build android" command and I was getting the same problem! The solution was simply

  • To install the required sdk
  • Run the same command in CMD must be as administrater

What is the most efficient way to create a dictionary of two pandas Dataframe columns?

TL;DR

>>> import pandas as pd
>>> df = pd.DataFrame({'Position':[1,2,3,4,5], 'Letter':['a', 'b', 'c', 'd', 'e']})
>>> dict(sorted(df.values.tolist())) # Sort of sorted... 
{'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5}
>>> from collections import OrderedDict
>>> OrderedDict(df.values.tolist())
OrderedDict([('a', 1), ('b', 2), ('c', 3), ('d', 4), ('e', 5)])

In Long

Explaining solution: dict(sorted(df.values.tolist()))

Given:

df = pd.DataFrame({'Position':[1,2,3,4,5], 'Letter':['a', 'b', 'c', 'd', 'e']})

[out]:

 Letter Position
0   a   1
1   b   2
2   c   3
3   d   4
4   e   5

Try:

# Get the values out to a 2-D numpy array, 
df.values

[out]:

array([['a', 1],
       ['b', 2],
       ['c', 3],
       ['d', 4],
       ['e', 5]], dtype=object)

Then optionally:

# Dump it into a list so that you can sort it using `sorted()`
sorted(df.values.tolist()) # Sort by key

Or:

# Sort by value:
from operator import itemgetter
sorted(df.values.tolist(), key=itemgetter(1))

[out]:

[['a', 1], ['b', 2], ['c', 3], ['d', 4], ['e', 5]]

Lastly, cast the list of list of 2 elements into a dict.

dict(sorted(df.values.tolist())) 

[out]:

{'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5}

Related

Answering @sbradbio comment:

If there are multiple values for a specific key and you would like to keep all of them, it's the not the most efficient but the most intuitive way is:

from collections import defaultdict
import pandas as pd

multivalue_dict = defaultdict(list)

df = pd.DataFrame({'Position':[1,2,4,4,4], 'Letter':['a', 'b', 'd', 'e', 'f']})

for idx,row in df.iterrows():
    multivalue_dict[row['Position']].append(row['Letter'])

[out]:

>>> print(multivalue_dict)
defaultdict(list, {1: ['a'], 2: ['b'], 4: ['d', 'e', 'f']})

How to save a figure in MATLAB from the command line?

I don't think you can save it without it appearing, but just for saving in multiple formats use the print command. See the answer posted here: Save an imagesc output in Matlab

INSTALL_FAILED_NO_MATCHING_ABIS when install apk

this problem is for CPU Architecture and you have some of the abi in the lib folder.

go to build.gradle for your app module and in android, block add this :

  splits {
            abi {
                enable true
                reset()
                include 'x86', 'armeabi-v7a'
                universalApk true
            }
        }

How to check ASP.NET Version loaded on a system?

You can use

<%
Response.Write("Version: " + System.Environment.Version.ToString());
%>

That will get the currently running version. You can check the registry for all installed versions at:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP

How to add background-image using ngStyle (angular2)?

Use Instead

[ngStyle]="{'background-image':' url(' + instagram?.image + ')'}"

How to choose the id generation strategy when using JPA and Hibernate

The API Doc are very clear on this.

All generators implement the interface org.hibernate.id.IdentifierGenerator. This is a very simple interface. Some applications can choose to provide their own specialized implementations, however, Hibernate provides a range of built-in implementations. The shortcut names for the built-in generators are as follows:

increment

generates identifiers of type long, short or int that are unique only when no other process is inserting data into the same table. Do not use in a cluster.

identity

supports identity columns in DB2, MySQL, MS SQL Server, Sybase and HypersonicSQL. The returned identifier is of type long, short or int.

sequence

uses a sequence in DB2, PostgreSQL, Oracle, SAP DB, McKoi or a generator in Interbase. The returned identifier is of type long, short or int

hilo

uses a hi/lo algorithm to efficiently generate identifiers of type long, short or int, given a table and column (by default hibernate_unique_key and next_hi respectively) as a source of hi values. The hi/lo algorithm generates identifiers that are unique only for a particular database.

seqhilo

uses a hi/lo algorithm to efficiently generate identifiers of type long, short or int, given a named database sequence.

uuid

uses a 128-bit UUID algorithm to generate identifiers of type string that are unique within a network (the IP address is used). The UUID is encoded as a string of 32 hexadecimal digits in length.

guid

uses a database-generated GUID string on MS SQL Server and MySQL.

native

selects identity, sequence or hilo depending upon the capabilities of the underlying database.

assigned

lets the application assign an identifier to the object before save() is called. This is the default strategy if no element is specified.

select

retrieves a primary key, assigned by a database trigger, by selecting the row by some unique key and retrieving the primary key value.

foreign

uses the identifier of another associated object. It is usually used in conjunction with a primary key association.

sequence-identity

a specialized sequence generation strategy that utilizes a database sequence for the actual value generation, but combines this with JDBC3 getGeneratedKeys to return the generated identifier value as part of the insert statement execution. This strategy is only supported on Oracle 10g drivers targeted for JDK 1.4. Comments on these insert statements are disabled due to a bug in the Oracle drivers.

If you are building a simple application with not much concurrent users, you can go for increment, identity, hilo etc.. These are simple to configure and did not need much coding inside the db.

You should choose sequence or guid depending on your database. These are safe and better because the id generation will happen inside the database.

Update: Recently we had an an issue with idendity where primitive type (int) this was fixed by using warapper type (Integer) instead.

Pylint "unresolved import" error in Visual Studio Code

To me the problem was related with the project that I was working on. It took me a while to figure it out, so I hope this helps:

Original folder structure:

    root/
    __init__.py  # Empty

        folder/
            __init__.py # Empty

            sub_folder_b/
                my_code.py
            sub_folder_c/
                another_code.py

In another_code.py:

from folder.sub_folder_b import my_code.py

This didn't trigger the intellisense in Visual Studio Code, but it did execute OK.

On the other hand, adding "root" on the import path, did make the intellisense work, but raised ModuleNotFoundError when executing:

from root.folder.sub_folder_b import my_code.py

The solution was to remove the _init_.py file inside the "folder" directory, leaving only the _init_.py located at /root.

How to configure robots.txt to allow everything?

It means you allow every (*) user-agent/crawler to access the root (/) of your site. You're okay.

Copying Code from Inspect Element in Google Chrome

(eg: div,footer,table) Right click -> Edit as HTML

Then you can copy and paster wherever you need...

that's all enjoy your coding.....

In Powershell what is the idiomatic way of converting a string to an int?

A quick true/false test of whether it will cast to [int]

[bool]($var -as [int] -is [int])

How can I get the MAC and the IP address of a connected client in PHP?

You can get MAC Address or Physical Address using this code

$d = explode('Physical Address. . . . . . . . .',shell_exec ("ipconfig/all"));  
$d1 = explode(':',$d[1]);  
$d2 = explode(' ',$d1[1]);  
return $d2[1];

I used explode many time because shell_exec ("ipconfig/all") return complete detail of all network. so you have to split one by one. when you run this code then you will get
your MAC Address 00-##-##-CV-12 //this is fake address for show only.

Get index of a key/value pair in a C# dictionary based on the value

Let's say you have a Dictionary called fooDictionary

fooDictionary.Values.ToList().IndexOf(someValue);

Values.ToList() converts your dictionary values into a List of someValue objects.

IndexOf(someValue) searches your new List looking for the someValue object in question and returns the Index which would match the index of the Key/Value pair in the dictionary.

This method does not care about the dictionary keys, it simply returns the index of the value that you are looking for.

This does not however account for the issue that there may be several matching "someValue" objects.

How to increase dbms_output buffer?

When buffer size gets full. There are several options you can try:

1) Increase the size of the DBMS_OUTPUT buffer to 1,000,000

2) Try filtering the data written to the buffer - possibly there is a loop that writes to DBMS_OUTPUT and you do not need this data.

3) Call ENABLE at various checkpoints within your code. Each call will clear the buffer.

DBMS_OUTPUT.ENABLE(NULL) will default to 20000 for backwards compatibility Oracle documentation on dbms_output

You can also create your custom output display.something like below snippets

create or replace procedure cust_output(input_string in varchar2 )
is 

   out_string_in long default in_string; 
   string_lenth number; 
   loop_count number default 0; 

begin 

   str_len := length(out_string_in);

   while loop_count < str_len
   loop 
      dbms_output.put_line( substr( out_string_in, loop_count +1, 255 ) ); 
      loop_count := loop_count +255; 
   end loop; 
end;

Link -Ref :Alternative to dbms_output.putline @ By: Alexander

How do I fix the error 'Named Pipes Provider, error 40 - Could not open a connection to' SQL Server'?

Very simple solution

use (local)\InstanceName that's it. it worked for me.

Disable future dates after today in Jquery Ui Datepicker

//Disable future dates after current date

$("#datepicker").datepicker('setEndDate', new Date());

//Disable past dates after current date

$("#datepicker").datepicker('setEndDate', new Date());

WHILE LOOP with IF STATEMENT MYSQL

I have discovered that you cannot have conditionals outside of the stored procedure in mysql. This is why the syntax error. As soon as I put the code that I needed between

   BEGIN
   SELECT MONTH(CURDATE()) INTO @curmonth;
   SELECT MONTHNAME(CURDATE()) INTO @curmonthname;
   SELECT DAY(LAST_DAY(CURDATE())) INTO @totaldays;
   SELECT FIRST_DAY(CURDATE()) INTO @checkweekday;
   SELECT DAY(@checkweekday) INTO @checkday;
   SET @daycount = 0;
   SET @workdays = 0;

     WHILE(@daycount < @totaldays) DO
       IF (WEEKDAY(@checkweekday) < 5) THEN
         SET @workdays = @workdays+1;
       END IF;
       SET @daycount = @daycount+1;
       SELECT ADDDATE(@checkweekday, INTERVAL 1 DAY) INTO @checkweekday;
     END WHILE;
   END

Just for others:

If you are not sure how to create a routine in phpmyadmin you can put this in the SQL query

    delimiter ;;
    drop procedure if exists test2;;
    create procedure test2()
    begin
    select ‘Hello World’;
    end
    ;;

Run the query. This will create a stored procedure or stored routine named test2. Now go to the routines tab and edit the stored procedure to be what you want. I also suggest reading http://net.tutsplus.com/tutorials/an-introduction-to-stored-procedures/ if you are beginning with stored procedures.

The first_day function you need is: How to get first day of every corresponding month in mysql?

Showing the Procedure is working Simply add the following line below END WHILE and above END

    SELECT @curmonth,@curmonthname,@totaldays,@daycount,@workdays,@checkweekday,@checkday;

Then use the following code in the SQL Query Window.

    call test2 /* or whatever you changed the name of the stored procedure to */

NOTE: If you use this please keep in mind that this code does not take in to account nationally observed holidays (or any holidays for that matter).

mysql after insert trigger which updates another table's column

Try this:

DELIMITER $$
CREATE TRIGGER occupy_trig
AFTER INSERT ON `OccupiedRoom` FOR EACH ROW
begin
       DECLARE id_exists Boolean;
       -- Check BookingRequest table
       SELECT 1
       INTO @id_exists
       FROM BookingRequest
       WHERE BookingRequest.idRequest= NEW.idRequest;

       IF @id_exists = 1
       THEN
           UPDATE BookingRequest
           SET status = '1'
           WHERE idRequest = NEW.idRequest;
        END IF;
END;
$$
DELIMITER ;

How to get the position of a character in Python?

There are two string methods for this, find() and index(). The difference between the two is what happens when the search string isn't found. find() returns -1 and index() raises ValueError.

Using find()

>>> myString = 'Position of a character'
>>> myString.find('s')
2
>>> myString.find('x')
-1

Using index()

>>> myString = 'Position of a character'
>>> myString.index('s')
2
>>> myString.index('x')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: substring not found

From the Python manual

string.find(s, sub[, start[, end]])
Return the lowest index in s where the substring sub is found such that sub is wholly contained in s[start:end]. Return -1 on failure. Defaults for start and end and interpretation of negative values is the same as for slices.

And:

string.index(s, sub[, start[, end]])
Like find() but raise ValueError when the substring is not found.

How to vertically align text in input type="text"?

Use padding to fake it since vertical-align doesn't work on text inputs.

jsFiddle example

CSS

.date-input {     
    width: 145px;
    padding-top: 80px;
}?

SQL Developer is returning only the date, not the time. How do I fix this?

To expand on some of the previous answers, I found that Oracle DATE objects behave different from Oracle TIMESTAMP objects. In particular, if you set your NLS_DATE_FORMAT to include fractional seconds, the entire time portion is omitted.

  • Format "YYYY-MM-DD HH24:MI:SS" works as expected, for DATE and TIMESTAMP
  • Format "YYYY-MM-DD HH24:MI:SSXFF" displays just the date portion for DATE, works as expected for TIMESTAMP

My personal preference is to set DATE to "YYYY-MM-DD HH24:MI:SS", and to set TIMESTAMP to "YYYY-MM-DD HH24:MI:SSXFF".

How to enable/disable bluetooth programmatically in android

Add the following permissions into your manifest file:

<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>

Enable bluetooth use this

BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();    
if (!mBluetoothAdapter.isEnabled()) {
    mBluetoothAdapter.enable(); 
}else{Toast.makeText(getApplicationContext(), "Bluetooth Al-Ready Enable", Toast.LENGTH_LONG).show();}

Disable bluetooth use this

BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();    
if (mBluetoothAdapter.isEnabled()) {
    mBluetoothAdapter.disable(); 
}

Apache: client denied by server configuration

Can you try changing "Allow from 127.0.0 192.168.1 ::1 localhost" to "Allow from all". If that fixes your problem, you need to be less restrict about where content can be requested from

Get a pixel from HTML Canvas?

// Get pixel data
var imageData = context.getImageData(x, y, width, height);

// Color at (x,y) position
var color = [];
color['red'] = imageData.data[((y*(imageData.width*4)) + (x*4)) + 0];
color['green'] = imageData.data[((y*(imageData.width*4)) + (x*4)) + 1];
color['blue'] = imageData.data[((y*(imageData.width*4)) + (x*4)) + 2];
color['alpha'] = imageData.data[((y*(imageData.width*4)) + (x*4)) + 3];

Pandas Split Dataframe into two Dataframes at a specific row

iloc

df1 = datasX.iloc[:, :72]
df2 = datasX.iloc[:, 72:]

(iloc docs)

Specifying and saving a figure with exact size in pixels

This worked for me, based on your code, generating a 93Mb png image with color noise and the desired dimensions:

import matplotlib.pyplot as plt
import numpy

w = 7195
h = 3841

im_np = numpy.random.rand(h, w)

fig = plt.figure(frameon=False)
fig.set_size_inches(w,h)
ax = plt.Axes(fig, [0., 0., 1., 1.])
ax.set_axis_off()
fig.add_axes(ax)
ax.imshow(im_np, aspect='normal')
fig.savefig('figure.png', dpi=1)

I am using the last PIP versions of the Python 2.7 libraries in Linux Mint 13.

Hope that helps!

XAMPP - Apache could not start - Attempting to start Apache service

when i run xampp control panel normal:

enter image description here

I had been run

I can’t start apache So, I will run it with administrator:

enter image description here

I can run apache

Insert text into textarea with jQuery

If you want to append content to the textarea without replacing them, You can try the below

$('textarea').append('Whatever need to be added');

According to your scenario it would be

$('a').click(function() 
{ 
  $('textarea').append($('#area').val()); 
})

Which "href" value should I use for JavaScript links, "#" or "javascript:void(0)"?

If you use a link as a way to just execute some JavaScript code (instead of using a span like D4V360 greatly suggested), just do:

<a href="javascript:(function()%7Balert(%22test%22)%3B%7D)()%3B">test</a>

If you're using a link with onclick for navigation, don't use href="#" as the fallback when JavaScript is off. It's usually very annoying when the user clicks on the link. Instead, provide the same link the onclick handler would provide if possible. If you can't do that, skip the onclick and just use a JavaScript URI in the href.

ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired

from here ORA-00054: resource busy and acquire with NOWAIT specified

You can also look up the sql,username,machine,port information and get to the actual process which holds the connection

SELECT O.OBJECT_NAME, S.SID, S.SERIAL#, P.SPID, S.PROGRAM,S.USERNAME,
S.MACHINE,S.PORT , S.LOGON_TIME,SQ.SQL_FULLTEXT 
FROM V$LOCKED_OBJECT L, DBA_OBJECTS O, V$SESSION S, 
V$PROCESS P, V$SQL SQ 
WHERE L.OBJECT_ID = O.OBJECT_ID 
AND L.SESSION_ID = S.SID AND S.PADDR = P.ADDR 
AND S.SQL_ADDRESS = SQ.ADDRESS;

How to solve SQL Server Error 1222 i.e Unlock a SQL Server table

To prevent this, make sure every BEGIN TRANSACTION has COMMIT

The following will say successful but will leave uncommitted transactions:

BEGIN TRANSACTION
BEGIN TRANSACTION
<SQL_CODE?
COMMIT

Closing query windows with uncommitted transactions will prompt you to commit your transactions. This will generally resolve the Error 1222 message.

Code line wrapping - how to handle long lines

IMHO this is the best way to write your line :

private static final Map<Class<? extends Persistent>, PersistentHelper> class2helper =
        new HashMap<Class<? extends Persistent>, PersistentHelper>();

This way the increased indentation without any braces can help you to see that the code was just splited because the line was too long. And instead of 4 spaces, 8 will make it clearer.

How to check for file lock?

No, unfortunately, and if you think about it, that information would be worthless anyway since the file could become locked the very next second (read: short timespan).

Why specifically do you need to know if the file is locked anyway? Knowing that might give us some other way of giving you good advice.

If your code would look like this:

if not locked then
    open and update file

Then between the two lines, another process could easily lock the file, giving you the same problem you were trying to avoid to begin with: exceptions.

Moving Average Pandas

To get the moving average in pandas we can use cum_sum and then divide by count.

Here is the working example:

import pandas as pd
import numpy as np

df = pd.DataFrame({'id': range(5),
                   'value': range(100,600,100)})

# some other similar statistics
df['cum_sum'] = df['value'].cumsum()
df['count'] = range(1,len(df['value'])+1)
df['mov_avg'] = df['cum_sum'] / df['count']

# other statistics
df['rolling_mean2'] = df['value'].rolling(window=2).mean()

print(df)

output

   id  value  cum_sum  count  mov_avg     rolling_mean2
0   0    100      100      1    100.0           NaN
1   1    200      300      2    150.0           150.0
2   2    300      600      3    200.0           250.0
3   3    400     1000      4    250.0           350.0
4   4    500     1500      5    300.0           450.0

How do I start/stop IIS Express Server?

You can stop any IIS Express application or you can stop all application. Right click on IIS express icon , which is located at right bottom corner of task bar. Then Select Show All Application

enter image description here

How to delete history of last 10 commands in shell?

Maybe will be useful for someone.
When you login to any user of any console/terminal history of your current session exists only in some "buffer" which flushes to ~/.bash_history on your logout.
So, to keep things secret you can just:
history -r && exit
and you will be logged out with all your session's (and only) history cleared ;)

How to pass the button value into my onclick event function?

You can pass the value to the function using this.value, where this points to the button

<input type="button" value="mybutton1" onclick="dosomething(this.value)">

And then access that value in the function

function dosomething(val){
  console.log(val);
}

excel - if cell is not blank, then do IF statement

Your formula is wrong. You probably meant something like:

=IF(AND(NOT(ISBLANK(Q2));NOT(ISBLANK(R2)));IF(Q2<=R2;"1";"0");"")

Another equivalent:

=IF(NOT(OR(ISBLANK(Q2);ISBLANK(R2)));IF(Q2<=R2;"1";"0");"")

Or even shorter:

=IF(OR(ISBLANK(Q2);ISBLANK(R2));"";IF(Q2<=R2;"1";"0"))

OR EVEN SHORTER:

=IF(OR(ISBLANK(Q2);ISBLANK(R2));"";--(Q2<=R2))

No connection could be made because the target machine actively refused it 127.0.0.1

Had the same problem, it turned out it was the WindowsFirewall blocking connections. Try to disable WindowsFirewall for a while to see if helps and if it is the problem open ports as needed.

How can I protect my .NET assemblies from decompilation?

No obsfuscator can protect your application, not even any one described here. See this link, it's an deobsfuscator which can deobsfuscate almost every obsfuscator out there.

https://github.com/0xd4d/de4dot

The best way which can help you (but remember that they are also not full prof) is to use mixed codes, code your important codes in unmanaged language and make a DLL like in C or C++ and then protect them either with Armageddon or Themida. Themida is not for every cracker, it's one of the best protector in the market, it can also protect your .NET software.

getString Outside of a Context or Activity

##Unique Approach

##App.getRes().getString(R.string.some_id)

This will work everywhere in app. (Util class, Dialog, Fragment or any class in your app)

(1) Create or Edit (if already exist) your Application class.

import android.app.Application;
import android.content.res.Resources;

public class App extends Application {
    private static App mInstance;
    private static Resources res;


    @Override
    public void onCreate() {
        super.onCreate();
        mInstance = this;
        res = getResources();
    }

    public static App getInstance() {
        return mInstance;
    }

    public static Resources getRes() {
        return res;
    }

}

(2) Add name field to your manifest.xml <application tag.

<application
        android:name=".App"
        ...
        >
        ...
    </application>

Now you are good to go. Use App.getRes().getString(R.string.some_id) anywhere in app.

Setting an image for a UIButton in code

In case of Swift User

// case of normal image
let image1 = UIImage(named: "your_image_file_name_without_extension")!
button1.setImage(image1, forState: UIControlState.Normal) 

// in case you don't want image to change when "clicked", you can leave code below
// case of when button is clicked
let image2 = UIImage(named: "image_clicked")!
button1.setImage(image2, forState: UIControlState.Highlight) 

Run ScrollTop with offset of element by ID

No magic involved, just subtract from the offset top of the element

$('html, body').animate({scrollTop: $('#contact').offset().top -100 }, 'slow');

Difference between database and schema

A database is the main container, it contains the data and log files, and all the schemas within it. You always back up a database, it is a discrete unit on its own.

Schemas are like folders within a database, and are mainly used to group logical objects together, which leads to ease of setting permissions by schema.

EDIT for additional question

drop schema test1

Msg 3729, Level 16, State 1, Line 1
Cannot drop schema 'test1' because it is being referenced by object 'copyme'.

You cannot drop a schema when it is in use. You have to first remove all objects from the schema.

Related reading:

  1. What good are SQL Server schemas?
  2. MSDN: User-Schema Separation

ES6 Map in Typescript

As a bare minimum:

tsconfig:

 "lib": [
      "es2015"
    ]

and install a polyfill such as https://github.com/zloirock/core-js if you want IE < 11 support: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map

Remove Primary Key in MySQL

ALTER TABLE `user_customer_permission` MODIFY `id` INT;
ALTER TABLE `user_customer_permission` DROP PRIMARY KEY;

How do I get the scroll position of a document?

document.getElementById("elementID").scrollHeight

$("elementID").scrollHeight

How do you set the width of an HTML Helper TextBox in ASP.NET MVC?

For this you have to use HtmlAttributes, but there is a catch: HtmlAttributes and css class .

you can define it like this:

new { Attrubute="Value", AttributeTwo = IntegerValue, @class="className" };

and here is a more realistic example:

new { style="width:50px" };
new { style="width:50px", maxsize = 50 };
new {size=30, @class="required"}

and finally in:

MVC 1

<%= Html.TextBox("test", new { style="width:50px" }) %> 

MVC 2

<%= Html.TextBox("test", null, new { style="width:50px" }) %> 

MVC 3

@Html.TextBox("test", null, new { style="width:50px" })

Using sed to split a string with a delimiter

Using \n in sed is non-portable. The portable way to do what you want with sed is:

sed 's/:/\
/g' ~/Desktop/myfile.txt

but in reality this isn't a job for sed anyway, it's the job tr was created to do:

tr ':' '
' < ~/Desktop/myfile.txt

Show popup after page load

Use this below code to display pop-up box on page load:

$(document).ready(function() { 
  var id = '#dialog';
  var maskHeight = $(document).height();
  var maskWidth = $(window).width();
  $('#mask').css({'width':maskWidth,'height':maskHeight}); 
  $('#mask').fadeIn(500); 
  $('#mask').fadeTo("slow",0.9); 
        var winH = $(window).height();
  var winW = $(window).width();
        $(id).css('top',  winH/2-$(id).height()/2);
  $(id).css('left', winW/2-$(id).width()/2);
     $(id).fadeIn(2000);  
     $('.window .close').click(function (e) {
  e.preventDefault();
  $('#mask').hide();
  $('.window').hide();
     });  
     $('#mask').click(function () {
  $(this).hide();
  $('.window').hide();
 });  

});

<div class="maintext">
<h2> Main text goes here...</h2>
</div>
<div id="boxes">
<div style="top: 50%; left: 50%; display: none;" id="dialog" class="window"> 
<div id="san">
<a href="#" class="close agree"><img src="close-icon.png" width="25" style="float:right; margin-right: -25px; margin-top: -20px;"></a>
<img src="san-web-corner.png" width="450">
</div>
</div>
<div style="width: 2478px; font-size: 32pt; color:white; height: 1202px; display: none; opacity: 0.4;" id="mask"></div>
</div>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.js"></script> 

I refereed this code from here Demo

Maximum call stack size exceeded error

Both invocations of the identical code below if decreased by 1 work in Chrome 32 on my computer e.g. 17905 vs 17904. If run as is they will produce the error "RangeError: Maximum call stack size exceeded". It appears to be this limit is not hardcoded but dependant on the hardware of your machine. It does appear that if invoked as a function this self-imposed limit is higher than if invoked as a method i.e. this particular code uses less memory when invoked as a function.

Invoked as a method:

var ninja = {
    chirp: function(n) {
        return n > 1 ? ninja.chirp(n-1) + "-chirp" : "chirp";
    }
};

ninja.chirp(17905);

Invoked as a function:

function chirp(n) {
    return n > 1 ? chirp( n - 1 ) + "-chirp" : "chirp";
}

chirp(20889);

What good are SQL Server schemas?

I think schemas are like a lot of new features (whether to SQL Server or any other software tool). You need to carefully evaluate whether the benefit of adding it to your development kit offsets the loss of simplicity in design and implementation.

It looks to me like schemas are roughly equivalent to optional namespaces. If you're in a situation where object names are colliding and the granularity of permissions is not fine enough, here's a tool. (I'd be inclined to say there might be design issues that should be dealt with at a more fundamental level first.)

The problem can be that, if it's there, some developers will start casually using it for short-term benefit; and once it's in there it can become kudzu.

Is there an R function for finding the index of an element in a vector?

The function match works on vectors:

x <- sample(1:10)
x
# [1]  4  5  9  3  8  1  6 10  7  2
match(c(4,8),x)
# [1] 1 5

match only returns the first encounter of a match, as you requested. It returns the position in the second argument of the values in the first argument.

For multiple matching, %in% is the way to go:

x <- sample(1:4,10,replace=TRUE)
x
# [1] 3 4 3 3 2 3 1 1 2 2
which(x %in% c(2,4))
# [1]  2  5  9 10

%in% returns a logical vector as long as the first argument, with a TRUE if that value can be found in the second argument and a FALSE otherwise.

Vagrant error : Failed to mount folders in Linux guest

Update February 2016

This took me hours to solve independently. Yes, this problem does still exist with latest Vagrant and Virtual Box installs:

?  vagrant -v
Vagrant 1.8.1
?  vboxmanage -v
5.0.14r105127

The symptoms for me were messages something like:

Checking for guest additions in VM... The guest additions on this VM do not match the installed version of VirtualBox!

followed by a failure to mount NFS drives.

1). Install the vagrant-vbguest plugin.

Depending on version of Vagrant you are using, issue one of the following commands:

# For vagrant < 1.1.5
$ vagrant gem install vagrant-vbguest

# For vagrant 1.1.5+
$ vagrant plugin install vagrant-vbguest

Next, do vagrant halt, followed by vagrant up - chances are you still have issues.

2). ssh into your guest and setup a soft link to the correct version of Guest Additions (here, 5.0.14).

$ vagrant ssh

$ sudo ln -s /opt/VBoxGuestAdditions-5.0.14/lib/VBoxGuestAdditions /usr/lib/VBoxGuestAdditions
$ exit

$ vagrant reload

You should be all good. By default, the mounted drive on guest is at /vagrant

Final comment:

IF you still have problems related to mounting NFS drives, then here is a workaround that worked for me. I had a vagrantfile with config something like:

Simply remove the mount type information, and slim down the mount_options settings so they work universally. Vagrant will now automatically choose the best synced folder option for your environment.

MVC Form not able to post List of objects

Please read this: http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx
You should set indicies for your html elements "name" attributes like planCompareViewModel[0].PlanId, planCompareViewModel[1].PlanId to make binder able to parse them into IEnumerable.
Instead of @foreach (var planVM in Model) use for loop and render names with indexes.

.mp4 file not playing in chrome

After running into the same issue - here're some of my thoughts:

  • due to Chrome removing support for h264, on some machines, mp4 videos encoded with it will either not work (throwing an Parser error when viewing under Firebug/Network tab - consistent with issue submitted here), or crash the browser, depending upon the encoding settings
  • it isn't consistent - it entirely depends upon the codecs installed on the computer - while I didn't encounter this issue on my machine, we did have one in the office where the issue occurred (and thus we used this one for testing)
  • it might to do with Quicktime / divX settings (the machine in question had an older version of Quicktime than my native one - we didn't want to loose our testing pc though, so we didn't update it).

As it affects only Chrome (other browsers work fine with VideoForEverybody solution) the solution I've used is:

for every mp4 file, create a Theora encoded mp4 file (example.mp4 -> example_c.mp4) apply following js:

if (window.chrome)
    $("[type=video\\\/mp4]").each(function()
    {
        $(this).attr('src', $(this).attr('src').replace(".mp4", "_c.mp4"));
    });

Unfortunately it's a bad Chrome hack, but hey, at least it works.

Source: user: eithedog

This also can help: chrome could play html5 mp4 video but html5test said chrome did not support mp4 video codec

Also check your version of crome here: html5test

Java - get pixel array from image

Mota's answer is great unless your BufferedImage came from a Monochrome Bitmap. A Monochrome Bitmap has only 2 possible values for its pixels (for example 0 = black and 1 = white). When a Monochrome Bitmap is used then the

final byte[] pixels = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();

call returns the raw Pixel Array data in such a fashion that each byte contains more than one pixel.

So when you use a Monochrome Bitmap image to create your BufferedImage object then this is the algorithm you want to use:

/**
 * This returns a true bitmap where each element in the grid is either a 0
 * or a 1. A 1 means the pixel is white and a 0 means the pixel is black.
 * 
 * If the incoming image doesn't have any pixels in it then this method
 * returns null;
 * 
 * @param image
 * @return
 */
public static int[][] convertToArray(BufferedImage image)
{

    if (image == null || image.getWidth() == 0 || image.getHeight() == 0)
        return null;

    // This returns bytes of data starting from the top left of the bitmap
    // image and goes down.
    // Top to bottom. Left to right.
    final byte[] pixels = ((DataBufferByte) image.getRaster()
            .getDataBuffer()).getData();

    final int width = image.getWidth();
    final int height = image.getHeight();

    int[][] result = new int[height][width];

    boolean done = false;
    boolean alreadyWentToNextByte = false;
    int byteIndex = 0;
    int row = 0;
    int col = 0;
    int numBits = 0;
    byte currentByte = pixels[byteIndex];
    while (!done)
    {
        alreadyWentToNextByte = false;

        result[row][col] = (currentByte & 0x80) >> 7;
        currentByte = (byte) (((int) currentByte) << 1);
        numBits++;

        if ((row == height - 1) && (col == width - 1))
        {
            done = true;
        }
        else
        {
            col++;

            if (numBits == 8)
            {
                currentByte = pixels[++byteIndex];
                numBits = 0;
                alreadyWentToNextByte = true;
            }

            if (col == width)
            {
                row++;
                col = 0;

                if (!alreadyWentToNextByte)
                {
                    currentByte = pixels[++byteIndex];
                    numBits = 0;
                }
            }
        }
    }

    return result;
}

How to retrieve absolute path given relative

Try realpath.

~ $ sudo apt-get install realpath  # may already be installed
~ $ realpath .bashrc
/home/username/.bashrc

To avoid expanding symlinks, use realpath -s.

The answer comes from "bash/fish command to print absolute path to a file".

Getting unique values in Excel by using formulas only

Assuming Column A contains the values you want to find single unique instance of, and has a Heading row I used the following formula. If you wanted it to scale with an unpredictable number of rows, you could replace A772 (where my data ended) with =ADDRESS(COUNTA(A:A),1).

=IF(COUNTIF(A5:$A$772,A5)=1,A5,"")

This will display the unique value at the LAST instance of each value in the column and doesn't assume any sorting. It takes advantage of the lack of absolutes to essentially have a decreasing "sliding window" of data to count. When the countif in the reduced window is equal to 1, then that row is the last instance of that value in the column.

Auto expand a textarea using jQuery

I wrote this jquery function that seems to work.

You need to specify min-height in css though, and unless you want to do some coding, it needs to be two digits long. ie 12px;

$.fn.expand_ta = function() {

var val = $(this).val();
val = val.replace(/</g, "&lt;");
val = val.replace(/>/g, "&gt;");
val += "___";

var ta_class = $(this).attr("class");
var ta_width = $(this).width();

var min_height = $(this).css("min-height").substr(0, 2);
min_height = parseInt(min_height);

$("#pixel_height").remove();
$("body").append('<pre class="'+ta_class+'" id="pixel_height" style="position: absolute; white-space: pre-wrap; visibility: hidden; word-wrap: break-word; width: '+ta_width+'px; height: auto;"></pre>');
$("#pixel_height").html(val);

var height = $("#pixel_height").height();
if (val.substr(-6) == "<br />"){
    height = height + min_height;
};
if (height >= min_height) $(this).css("height", height+"px");
else $(this).css("height", min_height+"px");
}

List vs tuple, when to use each?

A minor but notable advantage of a list over a tuple is that lists tend to be slightly more portable. Standard tools are less likely to support tuples. JSON, for example, does not have a tuple type. YAML does, but its syntax is ugly compared to its list syntax, which is quite nice.

In those cases, you may wish to use a tuple internally then convert to list as part of an export process. Alternately, you might want to use lists everywhere for consistency.

Debug JavaScript in Eclipse

In 2015, there are at least six choices for JavaScript debugging in Eclipse:

Adding to the above, here are a couple of videos which focus on "debugging JavaScript using eclipse"

Outdated

ASP.NET GridView RowIndex As CommandArgument

Here is Microsoft Suggestion for this http://msdn.microsoft.com/en-us/library/bb907626.aspx#Y800

On the gridview add a command button and convert it into a template, then give it a commandname in this case "AddToCart" and also add CommandArgument "<%# ((GridViewRow) Container).RowIndex %>"

<asp:TemplateField>
  <ItemTemplate>
    <asp:Button ID="AddButton" runat="server" 
      CommandName="AddToCart" 
      CommandArgument="<%# ((GridViewRow) Container).RowIndex %>"
      Text="Add to Cart" />
  </ItemTemplate> 
</asp:TemplateField>

Then for create on the RowCommand event of the gridview identify when the "AddToCart" command is triggered, and do whatever you want from there

protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
{
  if (e.CommandName == "AddToCart")
  {
    // Retrieve the row index stored in the 
    // CommandArgument property.
    int index = Convert.ToInt32(e.CommandArgument);

    // Retrieve the row that contains the button 
    // from the Rows collection.
    GridViewRow row = GridView1.Rows[index];

    // Add code here to add the item to the shopping cart.
  }
}

**One mistake I was making is that I wanted to add the actions on my template button instead of doing it directly on the RowCommand Event.

Difference between Arrays.asList(array) and new ArrayList<Integer>(Arrays.asList(array))

Summary of difference -

when list is created without using new operator Arrays.asList() method it return Wrapper which means

1. you can perform add/update Operation.

2. the changes done in original array will be reflected to List as well and vice versa.

Parsing ISO 8601 date in Javascript

The Date object handles 8601 as it's first parameter:

_x000D_
_x000D_
var d = new Date("2014-04-07T13:58:10.104Z");_x000D_
console.log(d.toString());
_x000D_
_x000D_
_x000D_

PHP script to loop through all of the files in a directory?

You can use the DirectoryIterator. Example from php Manual:

<?php
$dir = new DirectoryIterator(dirname(__FILE__));
foreach ($dir as $fileinfo) {
    if (!$fileinfo->isDot()) {
        var_dump($fileinfo->getFilename());
    }
}
?>

Error: No module named psycopg2.extensions

pip3 install django-psycopg2-extension

I know i am late and there's lot of answers up here which also solves the problem. But today i also faced this problem and none of this helps me. Then i found the above magical command which solves my problem :-P . so i am posting this as it might be case for you too.
Happy coding.