Programs & Examples On #Userappdatapath

Is it possible to declare a public variable in vba and assign a default value?

.NET has spoiled us :) Your declaration is not valid for VBA.

Only constants can be given a value upon application load. You declare them like so:

Public Const APOSTROPHE_KEYCODE = 222

Here's a sample declaration from one of my vba projects:

VBA Constant Image

If you're looking for something where you declare a public variable and then want to initialize its value, you need to create a Workbook_Open sub and do your initialization there. Example:

Private Sub Workbook_Open()
  Dim iAnswer As Integer

  InitializeListSheetDataColumns_S
  HideAllMonths_S

  If sheetSetupInfo.Range("D6").Value = "Enter Facility Name" Then
    iAnswer = MsgBox("It appears you have not yet set up this workbook.  Would you like to do so now?", vbYesNo)
    If iAnswer = vbYes Then
      sheetSetupInfo.Activate
      sheetSetupInfo.Range("D6").Select
      Exit Sub
    End If
  End If

  Application.Calculation = xlCalculationAutomatic
  sheetGeneralInfo.Activate
  Load frmInfoSheet
  frmInfoSheet.Show


End Sub

Make sure you declare the sub in the Workbook Object itself: enter image description here

npm not working - "read ECONNRESET"

Solution 1:

MAC + LINUX

run this command with sudo

sudo npm install -g yo

Windows

run cmd as administrator and then run this command again

Solution 2:

run this command and then try

npm config set registry http://registry.npmjs.org/

How to group an array of objects by key

Agree that unless you use these often there is no need for an external library. Although similar solutions are available, I see that some of them are tricky to follow here is a gist that has a solution with comments if you're trying to understand what is happening.

_x000D_
_x000D_
const cars = [{
  'make': 'audi',
  'model': 'r8',
  'year': '2012'
}, {
  'make': 'audi',
  'model': 'rs5',
  'year': '2013'
}, {
  'make': 'ford',
  'model': 'mustang',
  'year': '2012'
}, {
  'make': 'ford',
  'model': 'fusion',
  'year': '2015'
}, {
  'make': 'kia',
  'model': 'optima',
  'year': '2012'
}, ];

/**
 * Groups an array of objects by a key an returns an object or array grouped by provided key.
 * @param array - array to group objects by key.
 * @param key - key to group array objects by.
 * @param removeKey  - remove the key and it's value from the resulting object.
 * @param outputType - type of structure the output should be contained in.
 */
const groupBy = (
  inputArray,
  key,
  removeKey = false,
  outputType = {},
) => {
  return inputArray.reduce(
    (previous, current) => {
      // Get the current value that matches the input key and remove the key value for it.
      const {
        [key]: keyValue
      } = current;
      // remove the key if option is set
      removeKey && keyValue && delete current[key];
      // If there is already an array for the user provided key use it else default to an empty array.
      const {
        [keyValue]: reducedValue = []
      } = previous;

      // Create a new object and return that merges the previous with the current object
      return Object.assign(previous, {
        [keyValue]: reducedValue.concat(current)
      });
    },
    // Replace the object here to an array to change output object to an array
    outputType,
  );
};

console.log(groupBy(cars, 'make', true))
_x000D_
_x000D_
_x000D_

Git: can't undo local changes (error: path ... is unmerged)

I find git stash very useful for temporal handling of all 'dirty' states.

joining two select statements

Not sure what you are trying to do, but you have two select clauses. Do this instead:

SELECT * 
FROM ( SELECT * 
       FROM orders_products 
       INNER JOIN orders ON orders_products.orders_id = orders.orders_id 
       WHERE products_id = 181) AS A
JOIN ( SELECT * 
       FROM orders_products 
       INNER JOIN orders ON orders_products.orders_id = orders.orders_id
       WHERE products_id = 180) AS B

ON A.orders_id=B.orders_id

Update:

You could probably reduce it to something like this:

SELECT o.orders_id, 
       op1.products_id, 
       op1.quantity, 
       op2.products_id, 
       op2.quantity
FROM orders o
INNER JOIN orders_products op1 on o.orders_id = op1.orders_id  
INNER JOIN orders_products op2 on o.orders_id = op2.orders_id  
WHERE op1.products_id = 180
AND op2.products_id = 181

Convert Text to Date?

Solved the issue for me :

    Range(Cells(1, 1), Cells(100, 1)).Select

    For Each xCell In Selection

    xCell.Value = CDate(xCell.Value)

    Next xCell

Npm install failed with "cannot run in wd"

OP here, I have learned a lot more about node since I first asked this question. Though Dmitry's answer was very helpful, what ultimately did it for me is to install node with the correct permissions.

I highly recommend not installing node using any package managers, but rather to compile it yourself so that it resides in a local directory with normal permissions.

This article provides a very clear step-by-step instruction of how to do so:

https://www.digitalocean.com/community/tutorials/how-to-install-an-upstream-version-of-node-js-on-ubuntu-12-04

HTML/Javascript: how to access JSON data loaded in a script tag with src set

While it's not currently possible with the script tag, it is possible with an iframe if it's from the same domain.

<iframe
id="mySpecialId"
src="/my/link/to/some.json"
onload="(()=>{if(!window.jsonData){window.jsonData={}}try{window.jsonData[this.id]=JSON.parse(this.contentWindow.document.body.textContent.trim())}catch(e){console.warn(e)}this.remove();})();"
onerror="((err)=>console.warn(err))();"
style="display: none;"
></iframe>

To use the above, simply replace the id and src attribute with what you need. The id (which we'll assume in this situation is equal to mySpecialId) will be used to store the data in window.jsonData["mySpecialId"].

In other words, for every iframe that has an id and uses the onload script will have that data synchronously loaded into the window.jsonData object under the id specified.

I did this for fun and to show that it's "possible' but I do not recommend that it be used.


Here is an alternative that uses a callback instead.

<script>
    function someCallback(data){
        /** do something with data */
        console.log(data);

    }
    function jsonOnLoad(callback){
        const raw = this.contentWindow.document.body.textContent.trim();
        try {
          const data = JSON.parse(raw);
          /** do something with data */
          callback(data);
        }catch(e){
          console.warn(e.message);
        }
        this.remove();
    }
</script>
<!-- I frame with src pointing to json file on server, onload we apply "this" to have the iframe context, display none as we don't want to show the iframe -->
<iframe src="your/link/to/some.json" onload="jsonOnLoad.apply(this, someCallback)" style="display: none;"></iframe>

Tested in chrome and should work in firefox. Unsure about IE or Safari.

Cannot declare instance members in a static class in C#

I know this post is old but...

I was able to do this, my problem was that I forgot to make my property static.

public static class MyStaticClass
{
    private static NonStaticObject _myObject = new NonStaticObject();

    //property
    public static NonStaticObject MyObject
    {
        get { return _myObject; }
        set { _myObject = value; }
    }
}

ASP.NET GridView RowIndex As CommandArgument

I typically bind this data using the RowDatabound event with the GridView:

protected void FormatGridView(object sender, System.Web.UI.WebControls.GridViewRowEventArgs e)
{
   if (e.Row.RowType == DataControlRowType.DataRow) 
   {
      ((Button)e.Row.Cells(0).FindControl("btnSpecial")).CommandArgument = e.Row.RowIndex.ToString();
   }
}

javax.el.PropertyNotFoundException: Property 'foo' not found on type com.example.Bean

EL interprets ${class.name} as described - the name becomes getName() on the assumption you are using explicit or implicit methods of generating getter/setters

You can override this behavior by explicitly identifying the name as a function: ${class.name()} This calls the function name() directly without modification.

How do I install pip on macOS or OS X?

You should install Brew first:

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Then brew install Python

brew install python

Then pip will work

Can a shell script set environment variables of the calling shell?

You should use modules, see http://modules.sourceforge.net/

EDIT: The modules package has not been updated since 2012 but still works ok for the basics. All the new features, bells and whistles happen in lmod this day (which I like it more): https://www.tacc.utexas.edu/research-development/tacc-projects/lmod

Assembly - JG/JNLE/JL/JNGE after CMP

When you do a cmp a,b, the flags are set as if you had calculated a - b.

Then the jmp-type instructions check those flags to see if the jump should be made.

In other words, the first block of code you have (with my comments added):

cmp al,dl     ; set flags based on the comparison
jg label1     ; then jump based on the flags

would jump to label1 if and only if al was greater than dl.

You're probably better off thinking of it as al > dl but the two choices you have there are mathematically equivalent:

al > dl
al - dl > dl - dl (subtract dl from both sides)
al - dl > 0       (cancel the terms on the right hand side)

You need to be careful when using jg inasmuch as it assumes your values were signed. So, if you compare the bytes 101 (101 in two's complement) with 200 (-56 in two's complement), the former will actually be greater. If that's not what was desired, you should use the equivalent unsigned comparison.

See here for more detail on jump selection, reproduced below for completeness. First the ones where signed-ness is not appropriate:

+--------+------------------------------+-------------+--------------------+
|Instr   | Description                  | signed-ness | Flags              |
+--------+------------------------------+-------------+--------------------+
| JO     | Jump if overflow             |             | OF = 1             |
+--------+------------------------------+-------------+--------------------+
| JNO    | Jump if not overflow         |             | OF = 0             |
+--------+------------------------------+-------------+--------------------+
| JS     | Jump if sign                 |             | SF = 1             |
+--------+------------------------------+-------------+--------------------+
| JNS    | Jump if not sign             |             | SF = 0             |
+--------+------------------------------+-------------+--------------------+
| JE/    | Jump if equal                |             | ZF = 1             |
| JZ     | Jump if zero                 |             |                    |
+--------+------------------------------+-------------+--------------------+
| JNE/   | Jump if not equal            |             | ZF = 0             |
| JNZ    | Jump if not zero             |             |                    |
+--------+------------------------------+-------------+--------------------+
| JP/    | Jump if parity               |             | PF = 1             |
| JPE    | Jump if parity even          |             |                    |
+--------+------------------------------+-------------+--------------------+
| JNP/   | Jump if no parity            |             | PF = 0             |
| JPO    | Jump if parity odd           |             |                    |
+--------+------------------------------+-------------+--------------------+
| JCXZ/  | Jump if CX is zero           |             | CX = 0             |
| JECXZ  | Jump if ECX is zero          |             | ECX = 0            |
+--------+------------------------------+-------------+--------------------+

Then the unsigned ones:

+--------+------------------------------+-------------+--------------------+
|Instr   | Description                  | signed-ness | Flags              |
+--------+------------------------------+-------------+--------------------+
| JB/    | Jump if below                | unsigned    | CF = 1             |
| JNAE/  | Jump if not above or equal   |             |                    |
| JC     | Jump if carry                |             |                    |
+--------+------------------------------+-------------+--------------------+
| JNB/   | Jump if not below            | unsigned    | CF = 0             |
| JAE/   | Jump if above or equal       |             |                    |
| JNC    | Jump if not carry            |             |                    |
+--------+------------------------------+-------------+--------------------+
| JBE/   | Jump if below or equal       | unsigned    | CF = 1 or ZF = 1   |
| JNA    | Jump if not above            |             |                    |
+--------+------------------------------+-------------+--------------------+
| JA/    | Jump if above                | unsigned    | CF = 0 and ZF = 0  |
| JNBE   | Jump if not below or equal   |             |                    |
+--------+------------------------------+-------------+--------------------+

And, finally, the signed ones:

+--------+------------------------------+-------------+--------------------+
|Instr   | Description                  | signed-ness | Flags              |
+--------+------------------------------+-------------+--------------------+
| JL/    | Jump if less                 | signed      | SF <> OF           |
| JNGE   | Jump if not greater or equal |             |                    |
+--------+------------------------------+-------------+--------------------+
| JGE/   | Jump if greater or equal     | signed      | SF = OF            |
| JNL    | Jump if not less             |             |                    |
+--------+------------------------------+-------------+--------------------+
| JLE/   | Jump if less or equal        | signed      | ZF = 1 or SF <> OF |
| JNG    | Jump if not greater          |             |                    |
+--------+------------------------------+-------------+--------------------+
| JG/    | Jump if greater              | signed      | ZF = 0 and SF = OF |
| JNLE   | Jump if not less or equal    |             |                    |
+--------+------------------------------+-------------+--------------------+

Count number of occurrences by month

Make column B in sheet1 the dates but where the day of the month is always the first day of the month, e.g. in B2 put =DATE(YEAR(A2),MONTH(A2),1). Then make E5 on sheet 2 contain the first date of the month you need, e.g. Date(2013,4,1). After that, putting in F5 COUNTIF(Sheet1!B2:B50, E5) will give you the count for the month specified in E5.

How to easily initialize a list of Tuples?

Super Duper Old I know but I would add my piece on using Linq and continuation lambdas on methods with using C# 7. I try to use named tuples as replacements for DTOs and anonymous projections when reused in a class. Yes for mocking and testing you still need classes but doing things inline and passing around in a class is nice to have this newer option IMHO. You can instantiate them from

  1. Direct Instantiation
var items = new List<(int Id, string Name)> { (1, "Me"), (2, "You")};
  1. Off of an existing collection, and now you can return well typed tuples similar to how anonymous projections used to be done.
public class Hold
{
    public int Id { get; set; }
    public string Name { get; set; }
}

//In some method or main console app:
var holds = new List<Hold> { new Hold { Id = 1, Name = "Me" }, new Hold { Id = 2, Name = "You" } };
var anonymousProjections = holds.Select(x => new { SomeNewId = x.Id, SomeNewName = x.Name });
var namedTuples = holds.Select(x => (TupleId: x.Id, TupleName: x.Name));
  1. Reuse the tuples later with grouping methods or use a method to construct them inline in other logic:
//Assuming holder class above making 'holds' object
public (int Id, string Name) ReturnNamedTuple(int id, string name) => (id, name);
public static List<(int Id, string Name)> ReturnNamedTuplesFromHolder(List<Hold> holds) => holds.Select(x => (x.Id, x.Name)).ToList();
public static void DoSomethingWithNamedTuplesInput(List<(int id, string name)> inputs) => inputs.ForEach(x => Console.WriteLine($"Doing work with {x.id} for {x.name}"));

var namedTuples2 = holds.Select(x => ReturnNamedTuple(x.Id, x.Name));
var namedTuples3 = ReturnNamedTuplesFromHolder(holds);
DoSomethingWithNamedTuplesInput(namedTuples.ToList());

How to append text to an existing file in Java?

Shouldn't all of the answers here with try/catch blocks have the .close() pieces contained in a finally block?

Example for marked answer:

PrintWriter out = null;
try {
    out = new PrintWriter(new BufferedWriter(new FileWriter("writePath", true)));
    out.println("the text");
} catch (IOException e) {
    System.err.println(e);
} finally {
    if (out != null) {
        out.close();
    }
} 

Also, as of Java 7, you can use a try-with-resources statement. No finally block is required for closing the declared resource(s) because it is handled automatically, and is also less verbose:

try(PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("writePath", true)))) {
    out.println("the text");
} catch (IOException e) {
    System.err.println(e);
}

jQuery posting valid json in request body

An actual JSON request would look like this:

data: '{"command":"on"}',

Where you're sending an actual JSON string. For a more general solution, use JSON.stringify() to serialize an object to JSON, like this:

data: JSON.stringify({ "command": "on" }),

To support older browsers that don't have the JSON object, use json2.js which will add it in.


What's currently happening is since you have processData: false, it's basically sending this: ({"command":"on"}).toString() which is [object Object]...what you see in your request.

How to fix java.net.SocketException: Broken pipe?

SocketException: Broken pipe, is caused by the 'other end' (The client or the server) closing the connection while your code is either reading from or writing to the connection.

This is a very common exception in client/server applications that receive traffic from clients or servers outside of the application control. For example, the client is a browser. If the browser makes an Ajax call, and/or the user simply closes the page or browser, then this can effectively kill all communication unexpectedly. Basically, you will see this error any time the other end terminates their application, and you were not anticipating it.

If you experience this Exception in your application, then it means you should check your code where the IO (Input/Output) occurs and wrap it with a try/catch block to catch this IOException. It is then, up to you to decide how you want to handle this semi-valid situation.

In your case, the earliest place where you still have control is the call to HttpMethodDirector.executeWithRetry - So ensure that call is wrapped with the try/catch block, and handle it how you see fit.

I would strongly advise against logging SocketException-Broken Pipe specific errors at anything other than debug/trace levels. Else, this can be used as a form of DOS (Denial Of Service) attack by filling up the logs. Try and harden and negative-test your application for this common scenario.

MySQL Trigger after update only if row has changed

As a workaround, you could use the timestamp (old and new) for checking though, that one is not updated when there are no changes to the row. (Possibly that is the source for confusion? Because that one is also called 'on update' but is not executed when no change occurs) Changes within one second will then not execute that part of the trigger, but in some cases that could be fine (like when you have an application that rejects fast changes anyway.)

For example, rather than

IF NEW.a <> OLD.a or NEW.b <> OLD.b /* etc, all the way to NEW.z <> OLD.z */ 
THEN  
  INSERT INTO bar (a, b) VALUES(NEW.a, NEW.b) ;
END IF

you could use

IF NEW.ts <> OLD.ts 
THEN  
  INSERT INTO bar (a, b) VALUES(NEW.a, NEW.b) ;
END IF

Then you don't have to change your trigger every time you update the scheme (the issue you mentioned in the question.)

EDIT: Added full example

create table foo (a INT, b INT, ts TIMESTAMP);
create table bar (a INT, b INT);

INSERT INTO foo (a,b) VALUES(1,1);
INSERT INTO foo (a,b) VALUES(2,2);
INSERT INTO foo (a,b) VALUES(3,3);

DELIMITER ///

CREATE TRIGGER ins_sum AFTER UPDATE ON foo
    FOR EACH ROW
    BEGIN
        IF NEW.ts <> OLD.ts THEN  
            INSERT INTO bar (a, b) VALUES(NEW.a, NEW.b);
        END IF;
    END;
///

DELIMITER ;

select * from foo;
+------+------+---------------------+
| a    | b    | ts                  |
+------+------+---------------------+
|    1 |    1 | 2011-06-14 09:29:46 |
|    2 |    2 | 2011-06-14 09:29:46 |
|    3 |    3 | 2011-06-14 09:29:46 |
+------+------+---------------------+
3 rows in set (0.00 sec)

-- UPDATE without change
UPDATE foo SET b = 3 WHERE a = 3;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 1  Changed: 0  Warnings: 0

-- the timestamo didnt change
select * from foo WHERE a = 3;
+------+------+---------------------+
| a    | b    | ts                  |
+------+------+---------------------+
|    3 |    3 | 2011-06-14 09:29:46 |
+------+------+---------------------+
1 rows in set (0.00 sec)

-- the trigger didn't run
select * from bar;
Empty set (0.00 sec)

-- UPDATE with change
UPDATE foo SET b = 4 WHERE a=3;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

-- the timestamp changed
select * from foo;
+------+------+---------------------+
| a    | b    | ts                  |
+------+------+---------------------+
|    1 |    1 | 2011-06-14 09:29:46 |
|    2 |    2 | 2011-06-14 09:29:46 |
|    3 |    4 | 2011-06-14 09:34:59 |
+------+------+---------------------+
3 rows in set (0.00 sec)

-- and the trigger ran
select * from bar;
+------+------+---------------------+
| a    | b    | ts                  |
+------+------+---------------------+
|    3 |    4 | 2011-06-14 09:34:59 |
+------+------+---------------------+
1 row in set (0.00 sec)

It is working because of mysql's behavior on handling timestamps. The time stamp is only updated if a change occured in the updates.

Documentation is here:
https://dev.mysql.com/doc/refman/5.7/en/timestamp-initialization.html

desc foo;
+-------+-----------+------+-----+-------------------+-----------------------------+
| Field | Type      | Null | Key | Default           | Extra                       |
+-------+-----------+------+-----+-------------------+-----------------------------+
| a     | int(11)   | YES  |     | NULL              |                             |
| b     | int(11)   | YES  |     | NULL              |                             |
| ts    | timestamp | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+-------+-----------+------+-----+-------------------+-----------------------------+

Git diff between current branch and master but not including unmerged master commits

According to Documentation

git diff Shows changes between the working tree and the index or a tree, changes between the index and a tree, changes between two trees, changes resulting from a merge, changes between two blob objects, or changes between two files on disk.

In git diff - There's a significant difference between two dots .. and 3 dots ... in the way we compare branches or pull requests in our repository. I'll give you an easy example which demonstrates it easily.

Example: Let's assume we're checking out new branch from master and pushing some code in.

  G---H---I feature (Branch)
 /
A---B---C---D master (Branch)
  • Two dots - If we want to show the diffs between all changes happened in the current time on both sides, We would use the git diff origin/master..feature or just git diff origin/master
    ,output: ( H, I against A, B, C, D )

  • Three dots - If we want to show the diffs between the last common ancestor (A), aka the check point we started our new branch ,we use git diff origin/master...feature,output: (H, I against A ).

  • I'd rather use the 3 dots in most circumstances.

How do I "commit" changes in a git submodule?

$ git submodule status --recursive

Is also a life saver in this situation. You can use it and gitk --all to keep track of your sha1's and verify your sub-modules are pointing at what you think they are.

Bat file to run a .exe at the command prompt

To start a program and then close command prompt without waiting for program to exit:

start /d "path" file.exe

How to solve “Microsoft Visual Studio (VS)” error “Unable to connect to the configured development Web server”

I fixed the problem with deleting .vs folder on project folder.

  • Close VS projects.
  • Delete .vs folder on project folder that includes applicationhost.config file.

VS will generate new config for this project.

Differences in boolean operators: & vs && and | vs ||

&& ; || are logical operators.... short circuit

& ; | are boolean logical operators.... Non-short circuit

Moving to differences in execution on expressions. Bitwise operators evaluate both sides irrespective of the result of left hand side. But in the case of evaluating expressions with logical operators, the evaluation of the right hand expression is dependent on the left hand condition.

For Example:

int i = 25;
int j = 25;
if(i++ < 0 && j++ > 0)
    System.out.println("OK");
System.out.printf("i = %d ; j = %d",i,j);

This will print i=26 ; j=25, As the first condition is false the right hand condition is bypassed as the result is false anyways irrespective of the right hand side condition.(short circuit)

int i = 25;
int j = 25;
if(i++ < 0 & j++ > 0)
    System.out.println("OK");
System.out.printf("i = %d ; j = %d",i,j);

But, this will print i=26; j=26,

angular-cli server - how to specify default port

You can now specify the port in the .angular-cli.json under the defaults:

"defaults": {
  "styleExt": "scss",
  "serve": {
    "port": 8080
  },
  "component": {}
}

Tested in angular-cli v1.0.6

Why is Thread.Sleep so harmful

It is the 1).spinning and 2).polling loop of your examples that people caution against, not the Thread.Sleep() part. I think Thread.Sleep() is usually added to easily improve code that is spinning or in a polling loop, so it is just associated with "bad" code.

In addition people do stuff like:

while(inWait)Thread.Sleep(5000); 

where the variable inWait is not accessed in a thread-safe manner, which also causes problems.

What programmers want to see is the threads controlled by Events and Signaling and Locking constructs, and when you do that you won't have need for Thread.Sleep(), and the concerns about thread-safe variable access are also eliminated. As an example, could you create an event handler associated with the FileSystemWatcher class and use an event to trigger your 2nd example instead of looping?

As Andreas N. mentioned, read Threading in C#, by Joe Albahari, it is really really good.

How do I remove leading whitespace in Python?

If you want to cut the whitespaces before and behind the word, but keep the middle ones.
You could use:

word = '  Hello World  '
stripped = word.strip()
print(stripped)

How to compare variables to undefined, if I don’t know whether they exist?

if (!obj) {
    // object (not class!) doesn't exist yet
}
else ...

Can I load a UIImage from a URL?

Make sure enable this settings from iOS 9:

App Transport Security Settings in Info.plist to ensure loading image from URL so that it will allow download image and set it.

enter image description here

And write this code:

NSURL *url = [[NSURL alloc]initWithString:@"http://feelgrafix.com/data/images/images-1.jpg"];
NSData *data =[NSData dataWithContentsOfURL:url];
quickViewImage.image = [UIImage imageWithData:data];

Space between two rows in a table?

In the parent table, try setting

border-collapse:separate; 
border-spacing:5em;

Plus a border declaration, and see if this achieves your desired effect. Beware, though, that IE doesn't support the "separated borders" model.

How to allow users to check for the latest app version from inside the app?

I know the OP was very old, at that time in-app-update was not available. But from API 21, you can use in-app-update checking. You may need to keep your eyes on some points which are nicely written up here:

How do I get git to default to ssh and not https for new repositories

You may have accidentally cloned the repository in https instead of ssh. I've made this mistake numerous times on github. Make sure that you copy the ssh link in the first place when cloning, instead of the https link.

How to show all privileges from a user in oracle?

You can use below code to get all the privileges list from all users.

select * from dba_sys_privs 

How to insert close button in popover for Bootstrap

$popover = $el.popover({
  html: true
  placement: 'left'
  content: 'Do you want to a <b>review</b>? <a href="#" onclick="">Yes</a> <a href="#">No</a>'
  trigger: 'manual'
  container: $container // to contain the popup code
});

$popover.on('shown', function() {
  $container.find('.popover-content a').click( function() {
    $popover.popover('destroy')
  });
});

$popover.popover('show')'

Format a datetime into a string with milliseconds

@Cabbi raised the issue that on some systems, the microseconds format %f may give "0", so it's not portable to simply chop off the last three characters.

The following code carefully formats a timestamp with milliseconds:

from datetime import datetime
(dt, micro) = datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S.%f').split('.')
dt = "%s.%03d" % (dt, int(micro) / 1000)
print dt

Example Output:

2016-02-26 04:37:53.133

To get the exact output that the OP wanted, we have to strip punctuation characters:

from datetime import datetime
(dt, micro) = datetime.utcnow().strftime('%Y%m%d%H%M%S.%f').split('.')
dt = "%s%03d" % (dt, int(micro) / 1000)
print dt

Example Output:

20160226043839901

SQL Server Configuration Manager not found

If you happen to be using Windows 8 and up, here's how to get to it:

  • The newer Microsoft SQL Server Configuration Manager is a snap-in for the Microsoft Management Console program.

  • It is not a stand-alone program as used in the previous versions of Microsoft Windows operating systems.

  • SQL Server Configuration Manager doesn’t appear as an application when running Windows 8.

  • To open SQL Server Configuration Manager, in the Search charm, under Apps, type:

    SQLServerManager15.msc for [SQL Server 2019] or

    SQLServerManager14.msc for [SQL Server 2017] or

    SQLServerManager13.msc for [SQL Server 2016] or

    SQLServerManager12.msc for [SQL Server 2014] or

    SQLServerManager11.msc for [SQL Server 2012] or

    SQLServerManager10.msc for [SQL Server 2008], and then press Enter.

Text kindly reproduced from SQL Server Configuration Manager changes in Windows 8


Detailed info from MSDN: SQL Server Configuration Manager

How to disable a link using only CSS?

I searched over internet and found no better than this. Basically to disable button click functionality, just add CSS style using jQuery like so:

$("#myLink").css({ 'pointer-events': 'none' });

Then to enable it again do this

$("#myLink").css({ 'pointer-events': '' });

Checked on Firefox and IE 11, it worked.

OS X Sprite Kit Game Optimal Default Window Size

You should target the smallest, not the largest, supported pixel resolution by the devices your app can run on.

Say if there's an actual Mac computer that can run OS X 10.9 and has a native screen resolution of only 1280x720 then that's the resolution you should focus on. Any higher and your game won't correctly run on this device and you could as well remove that device from your supported devices list.

You can rely on upscaling to match larger screen sizes, but you can't rely on downscaling to preserve possibly important image details such as text or smaller game objects.

The next most important step is to pick a fitting aspect ratio, be it 4:3 or 16:9 or 16:10, that ideally is the native aspect ratio on most of the supported devices. Make sure your game only scales to fit on devices with a different aspect ratio.

You could scale to fill but then you must ensure that on all devices the cropped areas will not negatively impact gameplay or the use of the app in general (ie text or buttons outside the visible screen area). This will be harder to test as you'd actually have to have one of those devices or create a custom build that crops the view accordingly.

Alternatively you can design multiple versions of your game for specific and very common screen resolutions to provide the best game experience from 13" through 27" displays. Optimized designs for iMac (desktop) and a Macbook (notebook) devices make the most sense, it'll be harder to justify making optimized versions for 13" and 15" plus 21" and 27" screens.

But of course this depends a lot on the game. For example a tile-based world game could simply provide a larger viewing area onto the world on larger screen resolutions rather than scaling the view up. Provided that this does not alter gameplay, like giving the player an unfair advantage (specifically in multiplayer).

You should provide @2x images for the Retina Macbook Pro and future Retina Macs.

Input size vs width

HTML controls the semantic meaning of the elements. CSS controls the layout/style of the page. Use CSS when you are controlling your layout.

In short, never use size=""

Powershell: count members of a AD group

Something I'd like to share..

$adinfo.members actually give twice the number of actual members. $adinfo.member (without the "s") returns the correct amount. Even when dumping $adinfo.members & $adinfo.member to screen outputs the lower amount of members.

No idea how to explain this!

How do I add an "Add to Favorites" button or link on my website?

  if (window.sidebar) { // Mozilla Firefox Bookmark
     window.sidebar.addPanel(document.title,location.href,"");

It adds the bookmark but in the sidebar.

Determine the type of an object?

As an aside to the previous answers, it's worth mentioning the existence of collections.abc which contains several abstract base classes (ABCs) that complement duck-typing.

For example, instead of explicitly checking if something is a list with:

isinstance(my_obj, list)

you could, if you're only interested in seeing if the object you have allows getting items, use collections.abc.Sequence:

from collections.abc import Sequence
isinstance(my_obj, Sequence) 

if you're strictly interested in objects that allow getting, setting and deleting items (i.e mutable sequences), you'd opt for collections.abc.MutableSequence.

Many other ABCs are defined there, Mapping for objects that can be used as maps, Iterable, Callable, et cetera. A full list of all these can be seen in the documentation for collections.abc.

String or binary data would be truncated. The statement has been terminated

SQL Server 2016 SP2 CU6 and SQL Server 2017 CU12 introduced trace flag 460 in order to return the details of truncation warnings. You can enable it at the query level or at the server level.

Query level

INSERT INTO dbo.TEST (ColumnTest)
VALUES (‘Test truncation warnings’)
OPTION (QUERYTRACEON 460);
GO

Server Level

DBCC TRACEON(460, -1);
GO

From SQL Server 2019 you can enable it at database level:

ALTER DATABASE SCOPED CONFIGURATION 
SET VERBOSE_TRUNCATION_WARNINGS = ON;

The old output message is:

Msg 8152, Level 16, State 30, Line 13
String or binary data would be truncated.
The statement has been terminated.

The new output message is:

Msg 2628, Level 16, State 1, Line 30
String or binary data would be truncated in table 'DbTest.dbo.TEST', column 'ColumnTest'. Truncated value: ‘Test truncation warnings‘'.

In a future SQL Server 2019 release, message 2628 will replace message 8152 by default.

Before and After Suite execution hook in jUnit 4.x

As for "Note: we're using maven 2 for our build. I've tried using maven's pre- & post-integration-test phases, but, if a test fails, maven stops and doesn't run post-integration-test, which is no help."

you can try the failsafe-plugin instead, I think it has the facility to ensure cleanup occurs regardless of setup or intermediate stage status

Unable to install Android Studio in Ubuntu

None of these options worked for me on Ubuntu 12.10 (yeah, I need to upgrade). However, I found an easy solution. Download the source from here: https://github.com/miracle2k/android-platform_sdk/blob/master/emulator/mksdcard/mksdcard.c. Then simply compile with "gcc mksdcard.c -o mksdcard". Backup mksdcard in the SDK tools subfolder and replace with the newly compiled one. Android Studio will now be happy with your SDK.

Refresh an asp.net page on button click

  • Create a class for maintain hit counters

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

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

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

Understanding the Rails Authenticity Token

The authenticity token is used to prevent Cross-Site Request Forgery attacks (CSRF). To understand the authenticity token, you must first understand CSRF attacks.

CSRF

Suppose that you are the author of bank.com. You have a form on your site that is used to transfer money to a different account with a GET request:

enter image description here

A hacker could just send an HTTP request to the server saying GET /transfer?amount=$1000000&account-to=999999, right?

enter image description here

Wrong. The hackers attack won't work. The server will basically think?

Huh? Who is this guy trying to initiate a transfer. It's not the owner of the account, that's for sure.

How does the server know this? Because there's no session_id cookie authenticating the requester.

When you sign in with your username and password, the server sets a session_id cookie on your browser. That way, you don't have to authenticate each request with your username and password. When your browser sends the session_id cookie, the server knows:

Oh, that's John Doe. He signed in successfully 2.5 minutes ago. He's good to go.

A hacker might think:

Hmm. A normal HTTP request won't work, but if I could get my hand on that session_id cookie, I'd be golden.

The users browser has a bunch of cookies set for the bank.com domain. Every time the user makes a request to the bank.com domain, all of the cookies get sent along. Including the session_id cookie.

So if a hacker could get you to make the GET request that transfers money into his account, he'd be successful. How could he trick you into doing so? With Cross Site Request Forgery.

It's pretty simply, actually. The hacker could just get you to visit his website. On his website, he could have the following image tag:

<img src="http://bank.com/transfer?amount=$1000000&account-to=999999">

When the users browser comes across that image tag, it'll be making a GET request to that url. And since the request comes from his browser, it'll send with it all of the cookies associated with bank.com. If the user had recently signed in to bank.com... the session_id cookie will be set, and the server will think that the user meant to transfer $1,000,000 to account 999999!

enter image description here

Well, just don't visit dangerous sites and you'll be fine.

That isn't enough. What if someone posts that image to Facebook and it appears on your wall? What if it's injected into a site you're visiting with a XSS attack?

It's not so bad. Only GET requests are vulnerable.

Not true. A form that sends a POST request can be dynamically generated. Here's the example from the Rails Guide on Security:

<a href="http://www.harmless.com/" onclick="
  var f = document.createElement('form');
  f.style.display = 'none';
  this.parentNode.appendChild(f);
  f.method = 'POST';
  f.action = 'http://www.example.com/account/destroy';
  f.submit();
  return false;">To the harmless survey</a>

Authenticity Token

When your ApplicationController has this:

protect_from_forgery with: :exception

This:

<%= form_tag do %>
  Form contents
<% end %>

Is compiled into this:

<form accept-charset="UTF-8" action="/" method="post">
  <input name="utf8" type="hidden" value="&#x2713;" />
  <input name="authenticity_token" type="hidden" value="J7CBxfHalt49OSHp27hblqK20c9PgwJ108nDHX/8Cts=" />
  Form contents
</form>

In particular, the following is generated:

<input name="authenticity_token" type="hidden" value="J7CBxfHalt49OSHp27hblqK20c9PgwJ108nDHX/8Cts=" />

To protect against CSRF attacks, if Rails doesn't see the authenticity token sent along with a request, it won't consider the request safe.

How is an attacker supposed to know what this token is? A different value is generated randomly each time the form is generated:

enter image description here

A Cross Site Scripting (XSS) attack - that's how. But that's a different vulnerability for a different day.

When and Why to use abstract classes/methods?

Typically one uses an abstract class to provide some incomplete functionality that will be fleshed out by concrete subclasses. It may provide methods that are used by its subclasses; it may also represent an intermediate node in the class hierarchy, to represent a common grouping of concrete subclasses, distinguishing them in some way from other subclasses of its superclass. Since an interface can't derive from a class, this is another situation where a class (abstract or otherwise) would be necessary, versus an interface.

A good rule of thumb is that only leaf nodes of a class hierarchy should ever be instantiated. Making non-leaf nodes abstract is an easy way of ensuring that.

Why aren't python nested functions called closures?

Python 2 didn't have closures - it had workarounds that resembled closures.

There are plenty of examples in answers already given - copying in variables to the inner function, modifying an object on the inner function, etc.

In Python 3, support is more explicit - and succinct:

def closure():
    count = 0
    def inner():
        nonlocal count
        count += 1
        print(count)
    return inner

Usage:

start = closure()
start() # prints 1
start() # prints 2
start() # prints 3

The nonlocal keyword binds the inner function to the outer variable explicitly mentioned, in effect enclosing it. Hence more explicitly a 'closure'.

What is the fastest way to create a checksum for large files in C#

I know that I am late to party but performed test before actually implement the solution.

I did perform test against inbuilt MD5 class and also md5sum.exe. In my case inbuilt class took 13 second where md5sum.exe too around 16-18 seconds in every run.

    DateTime current = DateTime.Now;
    string file = @"C:\text.iso";//It's 2.5 Gb file
    string output;
    using (var md5 = MD5.Create())
    {
        using (var stream = File.OpenRead(file))
        {
            byte[] checksum = md5.ComputeHash(stream);
            output = BitConverter.ToString(checksum).Replace("-", String.Empty).ToLower();
            Console.WriteLine("Total seconds : " + (DateTime.Now - current).TotalSeconds.ToString() + " " + output);
        }
    }

IntelliJ IDEA 13 uses Java 1.5 despite setting to 1.7

I managed to fix this by changing settings for new projects:

  1. File -> New Projects Settings -> Settings for New Projects -> Java Compiler -> Set the version

  2. File -> New Projects Settings -> Structure for New Projects -> Project -> Set Project SDK + set language level

  3. Remove the projects

  4. Import the projects

Converting string to double in C#

You can try this example out. A simple C# progaram to convert string to double

class Calculations{

protected double length;
protected double height;
protected double width;

public void get_data(){

this.length = Convert.ToDouble(Console.ReadLine());
this.width  = Convert.ToDouble(Console.ReadLine());
this.height = Convert.ToDouble(Console.ReadLine());

   }
}

Get program path in VB.NET?

Set Your Own application Path

Dim myPathsValues As String

    TextBox1.Text = Application.StartupPath
    TextBox2.Text = Len(Application.StartupPath)
    TextBox3.Text = Microsoft.VisualBasic.Right(Application.StartupPath, 10)
    myPathsValues = Val(TextBox2.Text) - 9
    TextBox4.Text = Microsoft.VisualBasic.Left(Application.StartupPath, myPathsValues) & "Reports"

The mysqli extension is missing. Please check your PHP configuration

This article can help you Configuring PHP with MySQL for Apache 2 or IIS in Windows. Look at the section "Configure PHP and MySQL under Apache 2", point 3:

extension_dir = "c:\php\extensions"      ; FOR PHP 4 ONLY 
extension_dir = "c:\php\ext"             ; FOR PHP 5 ONLY

You must uncomment extension_dir param line and set it to absolute path to the PHP extensions directory.

XAMPP Port 80 in use by "Unable to open process" with PID 4

Simply set Apache to listen on a different port. This can be done by clicking on the "Config" button on the same line as the "Apache" module, select the "httpd.conf" file in the dropdown, then change the "Listen 80" line to "Listen 8080". Save the file and close it.

Now it avoids Port 80 and uses Port 8080 instead without issue. The only additional thing you need to do is make sure to put localhost:8080 in the browser so the browser knows to look on Port 8080. Otherwise it defaults to Port 80 and won't find your local site.

Get first element from a dictionary

Dictionary<string, Dictionary<string, string>> like = new Dictionary<string, Dictionary<string, string>>();
Dictionary<string, string> first = like.Values.First();

The openssl extension is required for SSL/TLS protection

The same error occurred to me. I fixed it by turning off TLS for Composer, it's not safe but I assumed the risk on my develop machine.

try this:

composer config -g -- disable-tls true

and re-run your Composer. It works to me!

But it's unsecure and not recommended for your Server. The official website says:

If set to true all HTTPS URLs will be tried with HTTP instead and no network-level encryption is performed. Enabling this is a security risk and is NOT recommended. The better way is to enable the php_openssl extension in php.ini.

If you don't want to enable unsecure layer in your machine/server, then setup your php to enable openssl and it also works. Make sure the PHP Openssl extension has been installed and enable it on php.ini file.


To enable OpenSSL, add or find and uncomment this line on your php.ini file:

Linux/OSx:

extension=php_openssl.so

Windows:

extension=php_openssl.dll

And reload your php-fpm / web-server if needed!

How do I create variable variables?

Use the built-in getattr function to get an attribute on an object by name. Modify the name as needed.

obj.spam = 'eggs'
name = 'spam'
getattr(obj, name)  # returns 'eggs'

Python NoneType object is not callable (beginner)

I faced the error "TypeError: 'NoneType' object is not callable " but for a different issue. With the above clues, i was able to debug and got it right! The issue that i faced was : I had the custome Library written and my file wasnt recognizing it although i had mentioned it

example: 
Library           ../../../libraries/customlibraries/ExtendedWaitKeywords.py
the keywords from my custom library were recognized and that error  was resolved only after specifying the complete path, as it was not getting the callable function.

Java8: sum values from specific field of the objects in a list

Try:

int sum = lst.stream().filter(o -> o.field > 10).mapToInt(o -> o.field).sum();

c# dictionary How to add multiple values for single key?

You could use my implementation of a multimap, which derives from a Dictionary<K, List<V>>. It is not perfect, however it does a good job.

/// <summary>
/// Represents a collection of keys and values.
/// Multiple values can have the same key.
/// </summary>
/// <typeparam name="TKey">Type of the keys.</typeparam>
/// <typeparam name="TValue">Type of the values.</typeparam>
public class MultiMap<TKey, TValue> : Dictionary<TKey, List<TValue>>
{

    public MultiMap()
        : base()
    {
    }

    public MultiMap(int capacity)
        : base(capacity)
    {
    }

    /// <summary>
    /// Adds an element with the specified key and value into the MultiMap. 
    /// </summary>
    /// <param name="key">The key of the element to add.</param>
    /// <param name="value">The value of the element to add.</param>
    public void Add(TKey key, TValue value)
    {
        List<TValue> valueList;

        if (TryGetValue(key, out valueList)) {
            valueList.Add(value);
        } else {
            valueList = new List<TValue>();
            valueList.Add(value);
            Add(key, valueList);
        }
    }

    /// <summary>
    /// Removes first occurence of an element with a specified key and value.
    /// </summary>
    /// <param name="key">The key of the element to remove.</param>
    /// <param name="value">The value of the element to remove.</param>
    /// <returns>true if the an element is removed;
    /// false if the key or the value were not found.</returns>
    public bool Remove(TKey key, TValue value)
    {
        List<TValue> valueList;

        if (TryGetValue(key, out valueList)) {
            if (valueList.Remove(value)) {
                if (valueList.Count == 0) {
                    Remove(key);
                }
                return true;
            }
        }
        return false;
    }

    /// <summary>
    /// Removes all occurences of elements with a specified key and value.
    /// </summary>
    /// <param name="key">The key of the elements to remove.</param>
    /// <param name="value">The value of the elements to remove.</param>
    /// <returns>Number of elements removed.</returns>
    public int RemoveAll(TKey key, TValue value)
    {
        List<TValue> valueList;
        int n = 0;

        if (TryGetValue(key, out valueList)) {
            while (valueList.Remove(value)) {
                n++;
            }
            if (valueList.Count == 0) {
                Remove(key);
            }
        }
        return n;
    }

    /// <summary>
    /// Gets the total number of values contained in the MultiMap.
    /// </summary>
    public int CountAll
    {
        get
        {
            int n = 0;

            foreach (List<TValue> valueList in Values) {
                n += valueList.Count;
            }
            return n;
        }
    }

    /// <summary>
    /// Determines whether the MultiMap contains an element with a specific
    /// key / value pair.
    /// </summary>
    /// <param name="key">Key of the element to search for.</param>
    /// <param name="value">Value of the element to search for.</param>
    /// <returns>true if the element was found; otherwise false.</returns>
    public bool Contains(TKey key, TValue value)
    {
        List<TValue> valueList;

        if (TryGetValue(key, out valueList)) {
            return valueList.Contains(value);
        }
        return false;
    }

    /// <summary>
    /// Determines whether the MultiMap contains an element with a specific value.
    /// </summary>
    /// <param name="value">Value of the element to search for.</param>
    /// <returns>true if the element was found; otherwise false.</returns>
    public bool Contains(TValue value)
    {
        foreach (List<TValue> valueList in Values) {
            if (valueList.Contains(value)) {
                return true;
            }
        }
        return false;
    }

}

Note that the Add method looks if a key is already present. If the key is new, a new list is created, the value is added to the list and the list is added to the dictionary. If the key was already present, the new value is added to the existing list.

How to write LDAP query to test if user is member of a group?

I would add one more thing to Marc's answer: The memberOf attribute can't contain wildcards, so you can't say something like "memberof=CN=SPS*", and expect it to find all groups that start with "SPS".

Two onClick actions one button

Try it:

<input type="button" value="Dont show this again! " onClick="fbLikeDump();WriteCookie();" />

Or also

<script>
function clickEvent(){
    fbLikeDump();
    WriteCookie();
}
</script>
<input type="button" value="Dont show this again! " onClick="clickEvent();" />

how to get the host url using javascript from the current page

You can get the protocol, host, and port using this:

window.location.origin

Browser compatibility

Desktop

Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
(Yes) (Yes) (Yes) (Yes) (Yes) (Yes)
30.0.1599.101 (possibly earlier) ? 21.0 (21.0) 11 ? 7 (possibly earlier, see webkit bug 46558)

Mobile

Android Edge Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
(Yes) (Yes) (Yes) (Yes) (Yes) (Yes)
30.0.1599.101 (possibly earlier) ? 21.0 (21.0) ? ? 7 (possibly earlier, see webkit bug 46558)

All browser compatibility is from Mozilla Developer Network

Git will not init/sync/update new submodules

There seems to be a lot of confusion here (also) in the answers.

git submodule init is not intended to magically generate stuff in .git/config (from .gitmodules). It is intended to set up something in an entirely empty subdirectory after cloning the parent project, or pulling a commit that adds a previously non-existing submodule.

In other words, you follow a git clone of a project that has submodules (which you will know by the fact that the clone checked out a .gitmodules file) by a git submodule update --init --recursive.

You do not follow git submodule add ... with a git submodule init (or git submodule update --init), that isn't supposed to work. In fact, the add will already update the appropriate .git/config if things work.

EDIT

If a previously non-existing git submodule was added by someone else, and you do a git pull of that commit, then the directory of that submodule will be entirely empty (when you execute git submodule status the new submodule's hash should be visible but will have a - in front of it.) In this case you need to follow your git pull also with a git submodule update --init (plus --recursive when it's a submodule inside a submodule) in order to get the new, previously non-existing, submodule checked out; just like after an initial clone of a project with submodules (where obviously you didn't have those submodules before either).

Is there a way to collapse all code blocks in Eclipse?

There is a hotkey, mapped by default to Ctrl+Shift+NUM_KEYPAD_DIVIDE.

You can change it to something else via Window -> Preferences, search for "Keys", then for "Collapse All".

To open all code blocks the shortcut is Ctrl+Shift+NUM_KEYPAD_MULTIPLY.

In the Eclipse extension PyDev, close all code blocks is Ctrl + 9

To open all blocks, is Ctrl + 0

String parsing in Java with delimiter tab "\t" using split

String[] columnDetail = new String[11];
columnDetail = column.split("\t", -1); // unlimited
OR
columnDetail = column.split("\t", 11); // if you are sure about limit.
 * The {@code limit} parameter controls the number of times the
 * pattern is applied and therefore affects the length of the resulting
 * array.  If the limit <i>n</i> is greater than zero then the pattern
 * will be applied at most <i>n</i>&nbsp;-&nbsp;1 times, the array's
 * length will be no greater than <i>n</i>, and the array's last entry
 * will contain all input beyond the last matched delimiter.  If <i>n</i>
 * is non-positive then the pattern will be applied as many times as
 * possible and the array can have any length.  If <i>n</i> is zero then
 * the pattern will be applied as many times as possible, the array can
 * have any length, and trailing empty strings will be discarded.

How to implement onBackPressed() in Fragments?

According to the AndroidX release notes, androidx.activity 1.0.0-alpha01 is released and introduces ComponentActivity, a new base class of the existing FragmentActivity and AppCompatActivity. And this release brings us a new feature:

You can now register an OnBackPressedCallback via addOnBackPressedCallback to receive onBackPressed() callbacks without needing to override the method in your activity.

How to populate HTML dropdown list with values from database

<?php
 $query = "select username from users";
 $res = mysqli_query($connection, $query);   
?>


<form>
  <select>
     <?php
       while ($row = $res->fetch_assoc()) 
       {
         echo '<option value=" '.$row['id'].' "> '.$row['name'].' </option>';
       }
    ?>
  </select>
</form>

Difference between 3NF and BCNF in simple terms (must be able to explain to an 8-year old)

Your pizza can have exactly three topping types:

  • one type of cheese
  • one type of meat
  • one type of vegetable

So we order two pizzas and choose the following toppings:

Pizza    Topping     Topping Type
-------- ----------  -------------
1        mozzarella  cheese
1        pepperoni   meat
1        olives      vegetable
2        mozzarella  meat
2        sausage     cheese
2        peppers     vegetable

Wait a second, mozzarella can't be both a cheese and a meat! And sausage isn't a cheese!

We need to prevent these sorts of mistakes, to make mozzarella always be cheese. We should use a separate table for this, so we write down that fact in only one place.

Pizza    Topping
-------- ----------
1        mozzarella
1        pepperoni
1        olives
2        mozzarella 
2        sausage
2        peppers

Topping     Topping Type
----------  -------------
mozzarella  cheese
pepperoni   meat
olives      vegetable
sausage     meat
peppers     vegetable

That was the explanation that an 8 year-old might understand. Here is the more technical version.

BCNF acts differently from 3NF only when there are multiple overlapping candidate keys.

The reason is that the functional dependency X -> Y is of course true if Y is a subset of X. So in any table that has only one candidate key and is in 3NF, it is already in BCNF because there is no column (either key or non-key) that is functionally dependent on anything besides that key.

Because each pizza must have exactly one of each topping type, we know that (Pizza, Topping Type) is a candidate key. We also know intuitively that a given topping cannot belong to different types simultaneously. So (Pizza, Topping) must be unique and therefore is also a candidate key. So we have two overlapping candidate keys.

I showed an anomaly where we marked mozarella as the wrong topping type. We know this is wrong, but the rule that makes it wrong is a dependency Topping -> Topping Type which is not a valid dependency for BCNF for this table. It's a dependency on something other than a whole candidate key.

So to solve this, we take Topping Type out of the Pizzas table and make it a non-key attribute in a Toppings table.

SQL Delete Records within a specific Range

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

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

jQuery UI Dialog with ASP.NET button postback

With ASP.NET just use UseSubmitBehavior="false" in your ASP.NET button:

<asp:Button ID="btnButton" runat="server"  Text="Button" onclick="btnButton_Click" UseSubmitBehavior="false" />       

Reference: Button.UseSubmitBehavior Property

UnsatisfiedDependencyException: Error creating bean with name 'entityManagerFactory'

The MySQL dependency should be like the following syntax in the pom.xml file.

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.21</version>
    </dependency>

Make sure the syntax, groupId, artifactId, Version has included in the dependancy.

add id to dynamically created <div>

Not sure if this is the best way, but it works.

if (cartDiv == null) {
    cartDiv = "<div id='unique_id'></div>"; // document.createElement('div');
    document.body.appendChild(cartDiv);
}

Stopping a windows service when the stop option is grayed out

If the stop option is greyed out then your service did not indicate that it was accepting SERVICE_ACCEPT_STOP when it last called SetServiceStatus. If you're using .NET, then you need to set the CanStop property in ServiceBase.

Of course, if you're accepting stop requests, then you'd better make sure that your service can safely handle those requests, especially if your service is still progressing through its startup code.

How do you detect/avoid Memory leaks in your (Unmanaged) code?

In C++: use RAII. Smart pointers like std::unique_ptr, std::shared_ptr, std::weak_ptr are your friends.

Increase JVM max heap size for Eclipse

Try to modify the eclipse.ini so that both Xms and Xmx are of the same value:

-Xms6000m
-Xmx6000m

This should force the Eclipse's VM to allocate 6GB of heap right from the beginning.

But be careful about either using the eclipse.ini or the command-line ./eclipse/eclipse -vmargs .... It should work in both cases but pick one and try to stick with it.

change Oracle user account status from EXPIRE(GRACE) to OPEN

set long 9999999
set lin 400
select DBMS_METADATA.GET_DDL('USER','YOUR_USER_NAME') from dual;

This will output something like this:

SQL> select DBMS_METADATA.GET_DDL('USER','WILIAM') from dual;

DBMS_METADATA.GET_DDL('USER','WILIAM')
--------------------------------------------------------------------------------

   CREATE USER "WILIAM" IDENTIFIED BY VALUES 'S:6680C1468F5F3B36B726CE7620F
FD9657F0E0E49AE56AAACE847BA368CEB;120F24A4C2554B4F'
      DEFAULT TABLESPACE "USER"
      TEMPORARY TABLESPACE "TEMP"
      PASSWORD EXPIRE

Just use the first piece of that with alter user instead:

ALTER USER "WILIAM" IDENTIFIED BY VALUES 'S:6680C1468F5F3B36B726CE7620F
FD9657F0E0E49AE56AAACE847BA368CEB;120F24A4C2554B4F';

This will put the account back in to OPEN status without changing the password (as long as you cut and paste correctly the hash value from the output of DBMS_METADATA.GET_DDL) and you don't even need to know what the password is.

What Makes a Method Thread-safe? What are the rules?

If a method (instance or static) only references variables scoped within that method then it is thread safe because each thread has its own stack:

In this instance, multiple threads could call ThreadSafeMethod concurrently without issue.

public class Thing
{
    public int ThreadSafeMethod(string parameter1)
    {
        int number; // each thread will have its own variable for number.
        number = parameter1.Length;
        return number;
    }
}

This is also true if the method calls other class method which only reference locally scoped variables:

public class Thing
{
    public int ThreadSafeMethod(string parameter1)
    {
        int number;
        number = this.GetLength(parameter1);
        return number;
    }

    private int GetLength(string value)
    {
        int length = value.Length;
        return length;
    }
}

If a method accesses any (object state) properties or fields (instance or static) then you need to use locks to ensure that the values are not modified by a different thread.

public class Thing
{
    private string someValue; // all threads will read and write to this same field value

    public int NonThreadSafeMethod(string parameter1)
    {
        this.someValue = parameter1;

        int number;

        // Since access to someValue is not synchronised by the class, a separate thread
        // could have changed its value between this thread setting its value at the start 
        // of the method and this line reading its value.
        number = this.someValue.Length;
        return number;
    }
}

You should be aware that any parameters passed in to the method which are not either a struct or immutable could be mutated by another thread outside the scope of the method.

To ensure proper concurrency you need to use locking.

for further information see lock statement C# reference and ReadWriterLockSlim.

lock is mostly useful for providing one at a time functionality,
ReadWriterLockSlim is useful if you need multiple readers and single writers.

Adding a UISegmentedControl to UITableView

   self.tableView.tableHeaderView = segmentedControl; 

If you want it to obey your width and height properly though enclose your segmentedControl in a UIView first as the tableView likes to mangle your view a bit to fit the width.

enter image description here enter image description here

How to check type of variable in Java?

None of these answers work if the variable is an uninitialized generic type

And from what I can find, it's only possible using an extremely ugly workaround, or by passing in an initialized parameter to your function, making it in-place, see here:

<T> T MyMethod(...){ if(T.class == MyClass.class){...}}

Is NOT valid because you cannot pull the type out of the T parameter directly, since it is erased at runtime time.

<T> void MyMethod(T out, ...){ if(out.getClass() == MyClass.class){...}}

This works because the caller is responsible to instantiating the variable out before calling. This will still throw an exception if out is null when called, but compared to the linked solution, this is by far the easiest way to do this

I know this is a kind of specific application, but since this is the first result on google for finding the type of a variable with java (and given that T is a kind of variable), I feel it should be included

Maven2: Missing artifact but jars are in place

I tried all of the above solutions except manually installing jar in my repository.

By deleting the _remote_repositories file in the same directory as the "missing jar file" and doing maven update I got it to work.

This is the same end result as manually installing, I presume.

Using union and order by clause in mysql

Just use order by column number (don't use column name). Every query returns some columns, so you can order by any desired column using it's number.

Are arrays in PHP copied as value or as reference to new variables, and when passed to functions?

To extend one of the answers, also subarrays of multidimensional arrays are passed by value unless passed explicitely by reference.

<?php
$foo = array( array(1,2,3), 22, 33);

function hello($fooarg) {
  $fooarg[0][0] = 99;
}

function world(&$fooarg) {
  $fooarg[0][0] = 66;
}

hello($foo);
var_dump($foo); // (original array not modified) array passed-by-value

world($foo);
var_dump($foo); // (original array modified) array passed-by-reference

The result is:

array(3) {
  [0]=>
  array(3) {
    [0]=>
    int(1)
    [1]=>
    int(2)
    [2]=>
    int(3)
  }
  [1]=>
  int(22)
  [2]=>
  int(33)
}
array(3) {
  [0]=>
  array(3) {
    [0]=>
    int(66)
    [1]=>
    int(2)
    [2]=>
    int(3)
  }
  [1]=>
  int(22)
  [2]=>
  int(33)
}

How does internationalization work in JavaScript?

Some of it is native, the rest is available through libraries.

For example Datejs is a good international date library.

For the rest, it's just about language translation, and JavaScript is natively Unicode compatible (as well as all major browsers).

JavaScript or jQuery browser back button click detector

there are a lot of ways how you can detect if user has clicked on the Back button. But everything depends on what your needs. Try to explore links below, they should help you.

Detect if user pressed "Back" button on current page:

Detect if current page is visited after pressing "Back" button on previous("Forward") page:

Built in Python hash() function

Hash results varies between 32bit and 64bit platforms

If a calculated hash shall be the same on both platforms consider using

def hash32(value):
    return hash(value) & 0xffffffff

Why and how to fix? IIS Express "The specified port is in use"

netstat didn't show anything already using the port

netstat -ano | findstr <your port number> showed nothing for me. I found out that port was excluded using this command to see what ranges are reserved by something else:

netsh interface ipv4 show excludedportrange protocol=tcp

You can try to unblock the range from the start port for a number of ports (need Command Prompt with Administrator):

netsh int ip delete excludedportrange protocol=tcp numberofports=<number of ports> startport=<start port>

However, in my case I couldn't unblock the range, I just got "Access is denied", so I ended up having to pick another port for my site.

My original solution: The only thing that worked was deleting the .vs folder in the solution folder. (I've since found you can just delete the .vs/config/applicationhost.config instead to avoid losing so many settings).

Generate getters and setters in NetBeans

Position the cursor inside the class, then press ALT + Ins and select Getters and Setters from the contextual menu.

Java, looping through result set

List<String> sids = new ArrayList<String>();
List<String> lids = new ArrayList<String>();

String query = "SELECT rlink_id, COUNT(*)"
             + "FROM dbo.Locate  "
             + "GROUP BY rlink_id ";

Statement stmt = yourconnection.createStatement();
try {
    ResultSet rs4 = stmt.executeQuery(query);

    while (rs4.next()) {
        sids.add(rs4.getString(1));
        lids.add(rs4.getString(2));
    }
} finally {
    stmt.close();
}

String show[] = sids.toArray(sids.size());
String actuate[] = lids.toArray(lids.size());

What is .htaccess file?

It's not part of PHP; it's part of Apache.

http://httpd.apache.org/docs/2.2/howto/htaccess.html

.htaccess files provide a way to make configuration changes on a per-directory basis.

Essentially, it allows you to take directives that would normally be put in Apache's main configuration files, and put them in a directory-specific configuration file instead. They're mostly used in cases where you don't have access to the main configuration files (e.g. a shared host).

How to remove elements/nodes from angular.js array

There is no rocket science in deleting items from array. To delete items from any array you need to use splice: $scope.items.splice(index, 1);. Here is an example:

HTML

<!DOCTYPE html>
<html data-ng-app="demo">
  <head>
    <script data-require="[email protected]" data-semver="1.1.5" src="https://ajax.googleapis.com/ajax/libs/angularjs/1.1.5/angular.js"></script>
    <link rel="stylesheet" href="style.css" />
    <script src="script.js"></script>
  </head>
  <body>
    <div data-ng-controller="DemoController">
      <ul>
        <li data-ng-repeat="item in items">
          {{item}}
          <button data-ng-click="removeItem($index)">Remove</button>
        </li>
      </ul>
      <input data-ng-model="newItem"><button data-ng-click="addItem(newItem)">Add</button>
    </div>
  </body>
</html>

JavaScript

"use strict";

var demo = angular.module("demo", []);

function DemoController($scope){
  $scope.items = [
    "potatoes",
    "tomatoes",
    "flour",
    "sugar",
    "salt"
  ];

  $scope.addItem = function(item){
    $scope.items.push(item);
    $scope.newItem = null;
  }

  $scope.removeItem = function(index){
    $scope.items.splice(index, 1);
  }
}

JSON encode MySQL results

My simple fix to stop it putting speech marks around numeric values...

while($r = mysql_fetch_assoc($rs)){
    while($elm=each($r))
    {
        if(is_numeric($r[$elm["key"]])){
                    $r[$elm["key"]]=intval($r[$elm["key"]]);
        }
    }
    $rows[] = $r;
}   

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

The answer above gave me the information needed to resolve this issue. In my case the url was incorrectly starting with ssh:///

To check the url in your git config is correct, open the git config file :-

git config --local -e

Check the url entry. It should NOT have ssh:/// at the start.

Incorrect entry:

 url = ssh:///[email protected]:username/repo.git

Correct entry:

 url = [email protected]:username/repo.git

If your url is correct, then the next step would be to try the answer above that suggests changing protocol to http.

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

Try using this tool,which is just a simple js script https://github.com/shashwatsahai/CSSExtractor/ This tool helps in getting the CSS from a specific page listing all sources for active styles and save it to a JSON with source as key and rules as value. It loads all the CSS from the href links and tells all the styles applied from them You can modify the code to save all css into a .css file. Thereby combining all your css.

SQL - How to select a row having a column with max value

In Oracle DB:

create table temp_test1 (id number, value number, description varchar2(20));

insert into temp_test1 values(1, 22, 'qq');
insert into temp_test1 values(2, 22, 'qq');
insert into temp_test1 values(3, 22, 'qq');
insert into temp_test1 values(4, 23, 'qq1');
insert into temp_test1 values(5, 23, 'qq1');
insert into temp_test1 values(6, 23, 'qq1');

SELECT MAX(id), value, description FROM temp_test1 GROUP BY value, description;

Result:
    MAX(ID) VALUE DESCRIPTION
    -------------------------
    6         23    qq1
    3         22    qq

What is the Python equivalent of Matlab's tic and toc functions?

I have just created a module [tictoc.py] for achieving nested tic tocs, which is what Matlab does.

from time import time

tics = []

def tic():
    tics.append(time())

def toc():
    if len(tics)==0:
        return None
    else:
        return time()-tics.pop()

And it works this way:

from tictoc import tic, toc

# This keeps track of the whole process
tic()

# Timing a small portion of code (maybe a loop)
tic()

# -- Nested code here --

# End
toc()  # This returns the elapse time (in seconds) since the last invocation of tic()
toc()  # This does the same for the first tic()

I hope it helps.

Starting a node.js server

Run cmd and then run node server.js. In your example, you are trying to use the REPL to run your command, which is not going to work. The ellipsis is node.js expecting more tokens before closing the current scope (you can type code in and run it on the fly here)

SOAP-UI - How to pass xml inside parameter

NOTE: This one is just an alternative for the previous provided .NET framework 3.5 and above

You can send it as raw xml

<test>or like this</test>

If you declare the paramater2 as XElement data type

Can you split a stream into two streams?

This was the least bad answer I could come up with.

import org.apache.commons.lang3.tuple.ImmutablePair;
import org.apache.commons.lang3.tuple.Pair;

public class Test {

    public static <T, L, R> Pair<L, R> splitStream(Stream<T> inputStream, Predicate<T> predicate,
            Function<Stream<T>, L> trueStreamProcessor, Function<Stream<T>, R> falseStreamProcessor) {

        Map<Boolean, List<T>> partitioned = inputStream.collect(Collectors.partitioningBy(predicate));
        L trueResult = trueStreamProcessor.apply(partitioned.get(Boolean.TRUE).stream());
        R falseResult = falseStreamProcessor.apply(partitioned.get(Boolean.FALSE).stream());

        return new ImmutablePair<L, R>(trueResult, falseResult);
    }

    public static void main(String[] args) {

        Stream<Integer> stream = Stream.iterate(0, n -> n + 1).limit(10);

        Pair<List<Integer>, String> results = splitStream(stream,
                n -> n > 5,
                s -> s.filter(n -> n % 2 == 0).collect(Collectors.toList()),
                s -> s.map(n -> n.toString()).collect(Collectors.joining("|")));

        System.out.println(results);
    }

}

This takes a stream of integers and splits them at 5. For those greater than 5 it filters only even numbers and puts them in a list. For the rest it joins them with |.

outputs:

 ([6, 8],0|1|2|3|4|5)

Its not ideal as it collects everything into intermediary collections breaking the stream (and has too many arguments!)

How can I download HTML source in C#

The newest, most recent, up to date answer
This post is really old (it's 7 years old when I answered it), so no one of the other answers used the new and recommended way, which is HttpClient class.


HttpClient is considered the new API and it should replace the old ones (WebClient and WebRequest)

string url = "page url";
HttpClient client = new HttpClient();
using (HttpResponseMessage response = client.GetAsync(url).Result)
{
   using (HttpContent content = response.Content)
   {
      string result = content.ReadAsStringAsync().Result;
   }
}

for more information about how to use the HttpClient class (especially in async cases), you can refer this question


NOTE 1: If you want to use async/await

string url = "page url";
HttpClient client = new HttpClient();   // actually only one object should be created by Application
using (HttpResponseMessage response = await client.GetAsync(url))
{
   using (HttpContent content = response.Content)
   {
      string result = await content.ReadAsStringAsync();
   }
}

NOTE 2: If use C# 8 features

string url = "page url";
HttpClient client = new HttpClient();
using HttpResponseMessage response = await client.GetAsync(url);
using HttpContent content = response.Content;
string result = await content.ReadAsStringAsync();

Can Json.NET serialize / deserialize to / from a stream?

UPDATE: This no longer works in the current version, see below for correct answer (no need to vote down, this is correct on older versions).

Use the JsonTextReader class with a StreamReader or use the JsonSerializer overload that takes a StreamReader directly:

var serializer = new JsonSerializer();
serializer.Deserialize(streamReader);

What are file descriptors, explained in simple terms?

Addition to above all simplified responses.

If you are working with files in bash script, it's better to use file descriptor.

For example: If you want to read and write from/to the file "test.txt", use the file descriptor as show below:

FILE=$1 # give the name of file in the command line
exec 5<>$FILE # '5' here act as the file descriptor

# Reading from the file line by line using file descriptor
while read LINE; do
    echo "$LINE"
done <&5

# Writing to the file using descriptor
echo "Adding the date: `date`" >&5 
exec 5<&- # Closing a file descriptor

Slide right to left Android Animations

See this link.. you can see so many kinds of animations here, just copy the xml to your res/anim folder and use it like the following..

listView.setAnimation(AnimationUtils.loadAnimation(MainActivity.this,R.anim.slide_in_right));

Animation Lists

How to implement a ViewPager with different Fragments / Layouts

As this is a very frequently asked question, I wanted to take the time and effort to explain the ViewPager with multiple Fragments and Layouts in detail. Here you go.

ViewPager with multiple Fragments and Layout files - How To

The following is a complete example of how to implement a ViewPager with different fragment Types and different layout files.

In this case, I have 3 Fragment classes, and a different layout file for each class. In order to keep things simple, the fragment-layouts only differ in their background color. Of course, any layout-file can be used for the Fragments.

FirstFragment.java has a orange background layout, SecondFragment.java has a green background layout and ThirdFragment.java has a red background layout. Furthermore, each Fragment displays a different text, depending on which class it is from and which instance it is.

Also be aware that I am using the support-library's Fragment: android.support.v4.app.Fragment

MainActivity.java (Initializes the Viewpager and has the adapter for it as an inner class). Again have a look at the imports. I am using the android.support.v4 package.

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;

public class MainActivity extends FragmentActivity {

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

        ViewPager pager = (ViewPager) findViewById(R.id.viewPager);
        pager.setAdapter(new MyPagerAdapter(getSupportFragmentManager()));
    }

    private class MyPagerAdapter extends FragmentPagerAdapter {

        public MyPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int pos) {
            switch(pos) {

            case 0: return FirstFragment.newInstance("FirstFragment, Instance 1");
            case 1: return SecondFragment.newInstance("SecondFragment, Instance 1");
            case 2: return ThirdFragment.newInstance("ThirdFragment, Instance 1");
            case 3: return ThirdFragment.newInstance("ThirdFragment, Instance 2");
            case 4: return ThirdFragment.newInstance("ThirdFragment, Instance 3");
            default: return ThirdFragment.newInstance("ThirdFragment, Default");
            }
        }

        @Override
        public int getCount() {
            return 5;
        }       
    }
}

activity_main.xml (The MainActivitys .xml file) - a simple layout file, only containing the ViewPager that fills the whole screen.

<android.support.v4.view.ViewPager
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/viewPager"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    />

The Fragment classes, FirstFragment.java import android.support.v4.app.Fragment;

public class FirstFragment extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.first_frag, container, false);

        TextView tv = (TextView) v.findViewById(R.id.tvFragFirst);
        tv.setText(getArguments().getString("msg"));

        return v;
    }

    public static FirstFragment newInstance(String text) {

        FirstFragment f = new FirstFragment();
        Bundle b = new Bundle();
        b.putString("msg", text);

        f.setArguments(b);

        return f;
    }
}

first_frag.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/holo_orange_dark" >

    <TextView
        android:id="@+id/tvFragFirst"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:textSize="26dp"
        android:text="TextView" />
</RelativeLayout>

SecondFragment.java

public class SecondFragment extends Fragment {

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.second_frag, container, false);

    TextView tv = (TextView) v.findViewById(R.id.tvFragSecond);
    tv.setText(getArguments().getString("msg"));

    return v;
}

public static SecondFragment newInstance(String text) {

    SecondFragment f = new SecondFragment();
    Bundle b = new Bundle();
    b.putString("msg", text);

    f.setArguments(b);

    return f;
}
}

second_frag.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/holo_green_dark" >

    <TextView
        android:id="@+id/tvFragSecond"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:textSize="26dp"
        android:text="TextView" />

</RelativeLayout>

ThirdFragment.java

public class ThirdFragment extends Fragment {

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.third_frag, container, false);

    TextView tv = (TextView) v.findViewById(R.id.tvFragThird);      
    tv.setText(getArguments().getString("msg"));

    return v;
}

public static ThirdFragment newInstance(String text) {

    ThirdFragment f = new ThirdFragment();
    Bundle b = new Bundle();
    b.putString("msg", text);

    f.setArguments(b);

    return f;
}
}

third_frag.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/holo_red_light" >

    <TextView
        android:id="@+id/tvFragThird"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:textSize="26dp"
        android:text="TextView" />

</RelativeLayout>

The end result is the following:

The Viewpager holds 5 Fragments, Fragments 1 is of type FirstFragment, and displays the first_frag.xml layout, Fragment 2 is of type SecondFragment and displays the second_frag.xml, and Fragment 3-5 are of type ThirdFragment and all display the third_frag.xml.

enter image description here

Above you can see the 5 Fragments between which can be switched via swipe to the left or right. Only one Fragment can be displayed at the same time of course.

Last but not least:

I would recommend that you use an empty constructor in each of your Fragment classes.

Instead of handing over potential parameters via constructor, use the newInstance(...) method and the Bundle for handing over parameters.

This way if detached and re-attached the object state can be stored through the arguments. Much like Bundles attached to Intents.

Automatically open default email client and pre-populate content

Implemented this way without using Jquery:

<button class="emailReplyButton" onClick="sendEmail(message)">Reply</button>

sendEmail(message) {
    var email = message.emailId;
    var subject = message.subject;
    var emailBody = 'Hi '+message.from;
    document.location = "mailto:"+email+"?subject="+subject+"&body="+emailBody;
}

Defining private module functions in python

In Python, "privacy" depends on "consenting adults'" levels of agreement - you can't force it (any more than you can in real life;-). A single leading underscore means you're not supposed to access it "from the outside" -- two leading underscores (w/o trailing underscores) carry the message even more forcefully... but, in the end, it still depends on social convention and consensus: Python's introspection is forceful enough that you can't handcuff every other programmer in the world to respect your wishes.

((Btw, though it's a closely held secret, much the same holds for C++: with most compilers, a simple #define private public line before #includeing your .h file is all it takes for wily coders to make hash of your "privacy"...!-))

nginx - client_max_body_size has no effect

I meet the same problem, but I found it nothing to do with nginx. I am using nodejs as backend server, use nginx as a reverse proxy, 413 code is triggered by node server. node use koa parse the body. koa limit the urlencoded length.

formLimit: limit of the urlencoded body. If the body ends up being larger than this limit, a 413 error code is returned. Default is 56kb.

set formLimit to bigger can solve this problem.

Modifying location.hash without page scrolling

Okay, this is a rather old topic but I thought I'd chip in as the 'correct' answer doesn't work well with CSS.

This solution basically prevents the click event from moving the page so we can get the scroll position first. Then we manually add the hash and the browser automatically triggers a hashchange event. We capture the hashchange event and scroll back to the correct position. A callback separates and prevents your code causing a delay by keeping your hash hacking in one place.

var hashThis = function( $elem, callback ){
    var scrollLocation;
    $( $elem ).on( "click", function( event ){
        event.preventDefault();
        scrollLocation = $( window ).scrollTop();
        window.location.hash = $( event.target ).attr('href').substr(1);
    });
    $( window ).on( "hashchange", function( event ){
        $( window ).scrollTop( scrollLocation );
        if( typeof callback === "function" ){
            callback();
        }
    });
}
hashThis( $( ".myAnchor" ), function(){
    // do something useful!
});

Using Regular Expressions to Extract a Value in Java

if you are reading from file then this can help you

              try{
             InputStream inputStream = (InputStream) mnpMainBean.getUploadedBulk().getInputStream();
             BufferedReader br = new BufferedReader(new InputStreamReader(inputStream));
             String line;
             //Ref:03
             while ((line = br.readLine()) != null) {
                if (line.matches("[A-Z],\\d,(\\d*,){2}(\\s*\\d*\\|\\d*:)+")) {
                     String[] splitRecord = line.split(",");
                     //do something
                 }
                 else{
                     br.close();
                     //error
                     return;
                 }
             }
                br.close();

             }
         }
         catch (IOException  ioExpception){
             logger.logDebug("Exception " + ioExpception.getStackTrace());
         }

TypeError: Cannot read property 'then' of undefined

You need to return your promise to the calling function.

islogged:function(){
    var cUid=sessionService.get('uid');
    alert("in loginServce, cuid is "+cUid);
    var $checkSessionServer=$http.post('data/check_session.php?cUid='+cUid);
    $checkSessionServer.then(function(){
        alert("session check returned!");
        console.log("checkSessionServer is "+$checkSessionServer);
    });
    return $checkSessionServer; // <-- return your promise to the calling function
}

Appending pandas dataframes generated in a for loop

you can try this.

data_you_need=pd.DataFrame()
for infile in glob.glob("*.xlsx"):
    data = pandas.read_excel(infile)
    data_you_need=data_you_need.append(data,ignore_index=True)

I hope it can help.

Looping through array and removing items, without breaking for loop

Here is another example for the proper use of splice. This example is about to remove 'attribute' from 'array'.

for (var i = array.length; i--;) {
    if (array[i] === 'attribute') {
        array.splice(i, 1);
    }
}

What is the role of the package-lock.json?

This file is automatically created and used by npm to keep track of your package installations and to better manage the state and history of your project’s dependencies. You shouldn’t alter the contents of this file.

Select from one table where not in another

So there's loads of posts on the web that show how to do this, I've found 3 ways, same as pointed out by Johan & Sjoerd. I couldn't get any of these queries to work, well obviously they work fine it's my database that's not working correctly and those queries all ran slow.

So I worked out another way that someone else may find useful:

The basic jist of it is to create a temporary table and fill it with all the information, then remove all the rows that ARE in the other table.

So I did these 3 queries, and it ran quickly (in a couple moments).

CREATE TEMPORARY TABLE

`database1`.`newRows`

SELECT

`t1`.`id` AS `columnID`

FROM

`database2`.`table` AS `t1`

.

CREATE INDEX `columnID` ON `database1`.`newRows`(`columnID`)

.

DELETE FROM `database1`.`newRows`

WHERE

EXISTS(
    SELECT `columnID` FROM `database1`.`product_details` WHERE `columnID`=`database1`.`newRows`.`columnID`
)

Error - Unable to access the IIS metabase

One more thing you could try:

  • Check if you have pending Windows updates.
  • If you do, please reboot before trying anything else.

I tend to never shut down my machine, so I had plenty of them waiting for a reboot. And that fixed it.

Facebook api: (#4) Application request limit reached

The Facebook "Graph API Rate Limiting" docs says that an error with code #4 is an app level rate limit, which is different than user level rate limits. Although it doesn't give any exact numbers, it describes their app level rate-limit as:

This rate limiting is applied globally at the app level. Ads api calls are excluded.

  • Rate limiting happens real time on sliding window for past one hour.
  • Stats is collected for number of calls and queries made, cpu time spent, memory used for each app.
  • There is a limit for each resource multiplied by monthly active users of a given app.
  • When the app uses more than its allowed resources the error is thrown.
  • Error, Code: 4, Message: Application request limit reached

The docs also give recommendations for avoiding the rate limits. For app level limits, they are:

Recommendations:

  • Verify the error code (4) to confirm the throttling type.
  • Do not make burst of calls, spread out the calls throughout the day.
  • Do smart fetching of data (important data, non duplicated data, etc).
    • Real-time insights, make sure API calls are structured in a way that you can read insights for as many as Page posts as possible, with minimum number of requests.
    • Don't fetch users feed twice (in the case that two App users have a specific friend in common)
    • Don't fetch all user's friends feed in a row if the number of friends is more than 250. Separate the fetches over different days. As an option, fetch first the app user's news feed (me/home) in order to detect which friends are more important to the App user. Then, fetch those friends feeds first.
  • Consider to limit/filter the requests by using the following parameters: "since", "until", "limit"
  • For page related calls use realtime updates to subscribe to changes in data.
  • Field expansion allows ton "join" multiple graph queries into a single call.
  • Etags to check if the data querying has changed since the last check.
  • For page management developers who does not have massive user base, have the admins of the page to accept the app to increase the number of users.

Finally, the docs give the following informational tips:

  • Batching calls will not reduce the number of api calls.
  • Making parallel calls will not reduce the number of api calls.

Webpack "OTS parsing error" loading fonts

I experienced the same problem, but for different reasons.

After Will Madden's solution didn't help, I tried every alternative fix I could find via the Intertubes - also to no avail. Exploring further, I just happened to open up one of the font files at issue. The original content of the file had somehow been overwritten by Webpack to include some kind of configuration info, likely from previous tinkering with the file-loader. I replaced the corrupted files with the originals, and voilà, the errors disappeared (for both Chrome and Firefox).

Creating a daemon in Linux

I can stop at the first requirement "A daemon which cannot be stopped ..."

Not possible my friend; however, you can achieve the same with a much better tool, a kernel module.

http://www.infoq.com/articles/inotify-linux-file-system-event-monitoring

All daemons can be stopped. Some are more easily stopped than others. Even a daemon pair with the partner in hold down, respawning the partner if lost, can be stopped. You just have to work a little harder at it.

How to convert POJO to JSON and vice versa?

Use GSON for converting POJO to JSONObject. Refer here.

For converting JSONObject to POJO, just call the setter method in the POJO and assign the values directly from the JSONObject.

How can I get all the request headers in Django?

<b>request.META</b><br>
{% for k_meta, v_meta in request.META.items %}
  <code>{{ k_meta }}</code> : {{ v_meta }} <br>
{% endfor %}

how to display employee names starting with a and then b in sql

select * 
from stores 
where name like 'a%' or 
name like 'b%' 
order by name

How to detect tableView cell touched or clicked in swift

 # Check delegate? first must be connected owner of view controller

    # Simple implementation of the didSelectRowAt function.

    func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
         print("row selection: \(indexPath.row)")
    }

What online brokers offer APIs?

There are a few. I was looking into MBTrading for a friend. I didn't get too far, as my friend lost interest. Seemed relatively straigt forward with a C# and VB.Net SDK. They had some docs and everything. This was ~6 months ago, so it may be better (or worse) by now.

IIRC, you can create a demo account for free. I don't remember all the details, but it let you connect to their test server and pull quotes and make fake trades and such to get your software fine tuned.

Don't know much about cost for an actual account or anything.

how to check for null with a ng-if values in a view with angularjs?

Here is a simple example that I tried to explain.

<div>
    <div *ngIf="product">     <!--If "product" exists-->
      <h2>Product Details</h2><hr>
      <h4>Name: {{ product.name }}</h4>
      <h5>Price: {{ product.price | currency }}</h5>
      <p> Description: {{ product.description }}</p>
    </div>

    <div *ngIf="!product">     <!--If "product" not exists-->
       *Product not found
    </div>
</div>

Excel VBA - Delete empty rows

How about

sub foo()
  dim r As Range, rows As Long, i As Long
  Set r = ActiveSheet.Range("A1:Z50")
  rows = r.rows.Count
  For i = rows To 1 Step (-1)
    If WorksheetFunction.CountA(r.rows(i)) = 0 Then r.rows(i).Delete
  Next
End Sub

Try this

Option Explicit

Sub Sample()
    Dim i As Long
    Dim DelRange As Range

    On Error GoTo Whoa

    Application.ScreenUpdating = False

    For i = 1 To 50
        If Application.WorksheetFunction.CountA(Range("A" & i & ":" & "Z" & i)) = 0 Then
            If DelRange Is Nothing Then
                Set DelRange = Range("A" & i & ":" & "Z" & i)
            Else
                Set DelRange = Union(DelRange, Range("A" & i & ":" & "Z" & i))
            End If
        End If
    Next i

    If Not DelRange Is Nothing Then DelRange.Delete shift:=xlUp
LetsContinue:
    Application.ScreenUpdating = True

    Exit Sub
Whoa:
    MsgBox Err.Description
    Resume LetsContinue
End Sub

IF you want to delete the entire row then use this code

Option Explicit

Sub Sample()
    Dim i As Long
    Dim DelRange As Range

    On Error GoTo Whoa

    Application.ScreenUpdating = False

    For i = 1 To 50
        If Application.WorksheetFunction.CountA(Range("A" & i & ":" & "Z" & i)) = 0 Then
            If DelRange Is Nothing Then
                Set DelRange = Rows(i)
            Else
                Set DelRange = Union(DelRange, Rows(i))
            End If
        End If
    Next i

    If Not DelRange Is Nothing Then DelRange.Delete shift:=xlUp
LetsContinue:
    Application.ScreenUpdating = True

    Exit Sub
Whoa:
    MsgBox Err.Description
    Resume LetsContinue
End Sub

How do you align left / right a div without using float?

No need to add extra elements. While flexbox uses very non-intuitive property names if you know what it can do you'll find yourself using it quite often.

<div style="display: flex; justify-content: space-between;">
<span>Item Left</span>
<span>Item Right</span>
</div>

Plan on needing this often?

.align_between {display: flex; justify-content: space-between;}

I see other people using secondary words in the primary position which makes a mess of information hierarchy. If align is the primary task and right, left, and/or between are the secondary the class should be .align_outer, not .outer_align as it will make sense as you vertically scan your code:

.align_between {}
.align_left {}
.align_outer {}
.align_right {}

Good habits over time will allow you to get to bed sooner than later.

Using cut command to remove multiple columns

You are able to cut all odd/even columns by using seq:

This would print all odd columns

echo 1,2,3,4,5,6,7,8,9,10 | cut -d, -f$(seq -s, 1 2 10)

To print all even columns you could use

echo 1,2,3,4,5,6,7,8,9,10 | cut -d, -f$(seq -s, 2 2 10)

By changing the second number of seq you can specify which columns to be printed.

If the specification which columns to print is more complex you could also use a "one-liner-if-clause" like

echo 1,2,3,4,5,6,7,8,9,10 | cut -d, -f$(for i in $(seq 1 10); do if [[ $i -lt 10 && $i -lt 5 ]];then echo -n $i,; else echo -n $i;fi;done)

This would print all columns from 1 to 5 - you can simply modify the conditions to create more complex conditions to specify weather a column shall be printed.

ERROR Error: StaticInjectorError(AppModule)[UserformService -> HttpClient]:

There are two reasons for this error

1) In the array of import if you imported HttpModule twice

enter image description here

2) If you haven't import:

import { HttpModule, JsonpModule } from '@angular/http'; 

If you want then run:

npm install @angular/http

Grep only the first match and stop

My grep-a-like program ack has a -1 option that stops at the first match found anywhere. It supports the -m 1 that @mvp refers to as well. I put it in there because if I'm searching a big tree of source code to find something that I know exists in only one file, it's unnecessary to find it and have to hit Ctrl-C.

How can I truncate a datetime in SQL Server?

For SQL Server 2008 only

CAST(@SomeDateTime AS Date) 

Then cast it back to datetime if you want

CAST(CAST(@SomeDateTime AS Date) As datetime)

Authentication failed for https://xxx.visualstudio.com/DefaultCollection/_git/project

After struggling with git authentication and azure devops server and trying other answers this tip here worked for me.

Using Visual Studio? Team Explorer handles authentication with Azure Repos for you.

Once I connected to the repo using Team Explorer I could use command line to execute git commands.

How to change href attribute using JavaScript after opening the link in a new window?

You can change this in the page load.

My intention is that when the page comes to the load function, switch the links (the current link in the required one)

Live-stream video from one android phone to another over WiFi

I did work on something like this once, but sending a video and playing it in real time is a really complex thing. I suggest you work with PNG's only. In my implementation What i did was capture PNGs using the host camera and then sending them over the network to the client, Which will display the image as soon as received and request the next image from the host. Since you are on wifi that communication will be fast enough to get around 8-10 images per-second(approximation only, i worked on Bluetooth). So this will look like a continuous video but with much less effort. For communication you may use UDP sockets(Faster and less complex) or DLNA (Not sure how that works).

How to import a module given its name as string?

The recommended way for Python 2.7 and 3.1 and later is to use importlib module:

importlib.import_module(name, package=None)

Import a module. The name argument specifies what module to import in absolute or relative terms (e.g. either pkg.mod or ..mod). If the name is specified in relative terms, then the package argument must be set to the name of the package which is to act as the anchor for resolving the package name (e.g. import_module('..mod', 'pkg.subpkg') will import pkg.mod).

e.g.

my_module = importlib.import_module('os.path')

How to get min, seconds and milliseconds from datetime.now() in python?

What about:

datetime.now().strftime('%M:%S.%f')[:-4]

I'm not sure what you mean by "Milliseconds only 2 digits", but this should keep it to 2 decimal places. There may be a more elegant way by manipulating the strftime format string to cut down on the precision as well -- I'm not completely sure.

EDIT

If the %f modifier doesn't work for you, you can try something like:

now=datetime.now()
string_i_want=('%02d:%02d.%d'%(now.minute,now.second,now.microsecond))[:-4]

Again, I'm assuming you just want to truncate the precision.

Set the Value of a Hidden field using JQuery

If you have a hidden field like this

  <asp:HiddenField ID="HiddenField1" runat="server" Value='<%# Eval("VertragNr") %>'/>

Now you can use your value like this

$(this).parent().find('input[type=hidden]').val()

How to upload a file and JSON data in Postman?

Postman multipart form-data content-type

Select [Content Type] from [SHOW COLUMNS] then set content-type of "application/json" to the parameter of json text.

HTML table with fixed headers and a fixed column?

The jQuery DataTables plug-in is one excellent way to achieve excel-like fixed column(s) and headers.

Note the examples section of the site and the "extras".
http://datatables.net/examples/
http://datatables.net/extras/

The "Extras" section has tools for fixed columns and fixed headers.

Fixed Columns
http://datatables.net/extras/fixedcolumns/
(I believe the example on this page is the one most appropriate for your question.)

Fixed Header
http://datatables.net/extras/fixedheader/
(Includes an example with a full page spreadsheet style layout: http://datatables.net/release-datatables/extras/FixedHeader/top_bottom_left_right.html)

Converting a character code to char (VB.NET)

You could use the Chr(int) function

How to change the color of an svg element?

here the fast&furious way :)

_x000D_
_x000D_
 body{
 background-color: #deff05;
 }
 
 svg{
   width: 30%;
    height: auto;
 }
 
 svg path {
    color:red;
    fill: currentcolor;
}
_x000D_
<svg xmlns="http://www.w3.org/2000/svg" version="1.1" id="Capa_1" x="0px" y="0px" viewBox="0 0 514.666 514.666"><path d="M514.666,210.489L257.333,99.353L0,210.489l45.933,19.837v123.939h30V243.282l33.052,14.274v107.678l4.807,4.453  c2.011,1.862,50.328,45.625,143.542,45.625c93.213,0,141.53-43.763,143.541-45.626l4.807-4.452V257.557L514.666,210.489z   M257.333,132.031L439,210.489l-181.667,78.458L75.666,210.489L257.333,132.031z M375.681,351.432  c-13.205,9.572-53.167,33.881-118.348,33.881c-65.23,0-105.203-24.345-118.348-33.875v-80.925l118.348,51.112l118.348-51.111  V351.432z"></path></svg>
_x000D_
_x000D_
_x000D_

How to change MySQL data directory?

It is also possible to symlink the datadir. At least in macOS, dev environment.

(homebrew) e. g.

# make sure you're not overwriting anything important, backup existing data
mv /usr/local/var/mysql [your preferred data directory] 
ln -s [your preferred data directory] /usr/local/var/mysql

Restart mysql.

KERNELBASE.dll Exception 0xe0434352 offset 0x000000000000a49d

0xe0434352 is the SEH code for a CLR exception. If you don't understand what that means, stop and read A Crash Course on the Depths of Win32™ Structured Exception Handling. So your process is not handling a CLR exception. Don't shoot the messenger, KERNELBASE.DLL is just the unfortunate victim. The perpetrator is MyApp.exe.

There should be a minidump of the crash in DrWatson folders with a full stack, it will contain everything you need to root cause the issue.

I suggest you wire up, in your myapp.exe code, AppDomain.UnhandledException and Application.ThreadException, as appropriate.

Java: get all variable names in a class

As mentioned by few users, below code can help find all the fields in a given class.

TestClass testObject= new TestClass().getClass();
Method[] methods = testObject.getMethods();
for (Method method:methods)
{
    String name=method.getName();
    if(name.startsWith("get"))
    {
        System.out.println(name.substring(3));
    }else if(name.startsWith("is"))
    {
        System.out.println(name.substring(2));
    }
}

However a more interesting approach is below:

With the help of Jackson library, I was able to find all class properties of type String/integer/double, and respective values in a Map class. (without using reflections api!)

TestClass testObject = new TestClass();
com.fasterxml.jackson.databind.ObjectMapper m = new com.fasterxml.jackson.databind.ObjectMapper();

Map<String,Object> props = m.convertValue(testObject, Map.class);

for(Map.Entry<String, Object> entry : props.entrySet()){
    if(entry.getValue() instanceof String || entry.getValue() instanceof Integer || entry.getValue() instanceof Double){
        System.out.println(entry.getKey() + "-->" + entry.getValue());
    }
}

How to assign a select result to a variable?

In order to assign a variable safely you have to use the SET-SELECT statement:

SET @PrimaryContactKey = (SELECT c.PrimaryCntctKey
    FROM tarcustomer c, tarinvoice i
    WHERE i.custkey = c.custkey 
    AND i.invckey = @tmp_key)

Make sure you have both a starting and an ending parenthesis!

The reason the SET-SELECT version is the safest way to set a variable is twofold.

1. The SELECT returns several posts

What happens if the following select results in several posts?

SELECT @PrimaryContactKey = c.PrimaryCntctKey
FROM tarcustomer c, tarinvoice i
WHERE i.custkey = c.custkey 
    AND i.invckey = @tmp_key

@PrimaryContactKey will be assigned the value from the last post in the result.

In fact @PrimaryContactKey will be assigned one value per post in the result, so it will consequently contain the value of the last post the SELECT-command was processing.

Which post is "last" is determined by any clustered indexes or, if no clustered index is used or the primary key is clustered, the "last" post will be the most recently added post. This behavior could, in a worst case scenario, be altered every time the indexing of the table is changed.

With a SET-SELECT statement your variable will be set to null.

2. The SELECT returns no posts

What happens, when using the second version of the code, if your select does not return a result at all?

In a contrary to what you may believe the value of the variable will not be null - it will retain it's previous value!

This is because, as stated above, SQL will assign a value to the variable once per post - meaning it won't do anything with the variable if the result contains no posts. So, the variable will still have the value it had before you ran the statement.

With the SET-SELECT statement the value will be null.

See also: SET versus SELECT when assigning variables?

Append an int to a std::string

The std::string::append() method expects its argument to be a NULL terminated string (char*).

There are several approaches for producing a string containg an int:

  • std::ostringstream

    #include <sstream>
    
    std::ostringstream s;
    s << "select logged from login where id = " << ClientID;
    std::string query(s.str());
    
  • std::to_string (C++11)

    std::string query("select logged from login where id = " +
                      std::to_string(ClientID));
    
  • boost::lexical_cast

    #include <boost/lexical_cast.hpp>
    
    std::string query("select logged from login where id = " +
                      boost::lexical_cast<std::string>(ClientID));
    

.keyCode vs. .which

Note: The answer below was written in 2010. Here many years later, both keyCode and which are deprecated in favor of key (for the logical key) and code (for the physical placement of the key). But note that IE doesn't support code, and its support for key is based on an older version of the spec so isn't quite correct. As I write this, the current Edge based on EdgeHTML and Chakra doesn't support code either, but Microsoft is rolling out its Blink- and V8- based replacement for Edge, which presumably does/will.


Some browsers use keyCode, others use which.

If you're using jQuery, you can reliably use which as jQuery standardizes things; More here.

If you're not using jQuery, you can do this:

var key = 'which' in e ? e.which : e.keyCode;

Or alternatively:

var key = e.which || e.keyCode || 0;

...which handles the possibility that e.which might be 0 (by restoring that 0 at the end, using JavaScript's curiously-powerful || operator).

Insert line break in wrapped cell via code

Yes there are two way to add a line feed:

  1. Use the existing function from VBA vbCrLf in the string you want to add a line feed, as such:

    Dim text As String

    text = "Hello" & vbCrLf & "World!"

    Worksheets(1).Cells(1, 1) = text

  2. Use the Chr() function and pass the ASCII characters 13 and 10 in order to add a line feed, as shown bellow:

    Dim text As String

    text = "Hello" & Chr(13) & Chr(10) & "World!"

    Worksheets(1).Cells(1, 1) = text

In both cases, you will have the same output in cell (1,1) or A1.

Pip install - Python 2.7 - Windows 7

It is possible that in python 2.7 pip is installed by default. if it is not then you can execute

python -m ensurepip --default-pip

This worked for me.

Source: https://docs.python.org/2/installing/

What is the best algorithm for overriding GetHashCode?

I ran into an issue with floats and decimals using the implementation selected as the answer above.

This test fails (floats; hash is the same even though I switched 2 values to be negative):

        var obj1 = new { A = 100m, B = 100m, C = 100m, D = 100m};
        var obj2 = new { A = 100m, B = 100m, C = -100m, D = -100m};
        var hash1 = ComputeHash(obj1.A, obj1.B, obj1.C, obj1.D);
        var hash2 = ComputeHash(obj2.A, obj2.B, obj2.C, obj2.D);
        Assert.IsFalse(hash1 == hash2, string.Format("Hashcode values should be different   hash1:{0}  hash2:{1}",hash1,hash2));

But this test passes (with ints):

        var obj1 = new { A = 100m, B = 100m, C = 100, D = 100};
        var obj2 = new { A = 100m, B = 100m, C = -100, D = -100};
        var hash1 = ComputeHash(obj1.A, obj1.B, obj1.C, obj1.D);
        var hash2 = ComputeHash(obj2.A, obj2.B, obj2.C, obj2.D);
        Assert.IsFalse(hash1 == hash2, string.Format("Hashcode values should be different   hash1:{0}  hash2:{1}",hash1,hash2));

I changed my implementation to not use GetHashCode for the primitive types and it seems to work better

    private static int InternalComputeHash(params object[] obj)
    {
        unchecked
        {
            var result = (int)SEED_VALUE_PRIME;
            for (uint i = 0; i < obj.Length; i++)
            {
                var currval = result;
                var nextval = DetermineNextValue(obj[i]);
                result = (result * MULTIPLIER_VALUE_PRIME) + nextval;

            }
            return result;
        }
    }



    private static int DetermineNextValue(object value)
    {
        unchecked
        {

                int hashCode;
                if (value is short
                    || value is int
                    || value is byte
                    || value is sbyte
                    || value is uint
                    || value is ushort
                    || value is ulong
                    || value is long
                    || value is float
                    || value is double
                    || value is decimal)
                {
                    return Convert.ToInt32(value);
                }
                else
                {
                    return value != null ? value.GetHashCode() : 0;
                }
        }
    }

How to commit to remote git repository

Have you tried git push? gitref.org has a nice section dealing with remote repositories.

You can also get help from the command line using the --help option. For example:

% git push --help
GIT-PUSH(1)                             Git Manual                             GIT-PUSH(1)



NAME
       git-push - Update remote refs along with associated objects

SYNOPSIS
       git push [--all | --mirror | --tags] [-n | --dry-run] [--receive-pack=<git-receive-pack>]
                  [--repo=<repository>] [-f | --force] [-v | --verbose] [-u | --set-upstream]
                  [<repository> [<refspec>...]]
...

Concatenate a vector of strings/character

For sdata:

gsub(", ","",toString(sdata))

For a vector of integers:

gsub(", ","",toString(c(1:10)))

Regular expression for address field validation

I have succesfully used ;

Dim regexString = New stringbuilder
    With regexString
       .Append("(?<h>^[\d]+[ ])(?<s>.+$)|")                'find the 2013 1st ambonstreet 
       .Append("(?<s>^.*?)(?<h>[ ][\d]+[ ])(?<e>[\D]+$)|") 'find the 1-7-4 Dual Ampstreet 130 A
       .Append("(?<s>^[\D]+[ ])(?<h>[\d]+)(?<e>.*?$)|")    'find the Terheydenlaan 320 B3 
       .Append("(?<s>^.*?)(?<h>\d*?$)")                    'find the 245e oosterkade 9
    End With

    Dim Address As Match = Regex.Match(DataRow("customerAddressLine1"), regexString.ToString(), RegexOptions.Multiline)

    If Not String.IsNullOrEmpty(Address.Groups("s").Value) Then StreetName = Address.Groups("s").Value
    If Not String.IsNullOrEmpty(Address.Groups("h").Value) Then HouseNumber = Address.Groups("h").Value
    If Not String.IsNullOrEmpty(Address.Groups("e").Value) Then Extension = Address.Groups("e").Value

The regex will attempt to find a result, if there is none, it move to the next alternative. If no result is found, none of the 4 formats where present.

What is the difference between %g and %f in C?

%f and %g does the same thing. Only difference is that %g is the shorter form of %f. That is the precision after decimal point is larger in %f compared to %g

How to convert a string to lower case in Bash?

tr:

a="$(tr [A-Z] [a-z] <<< "$a")"

AWK:

{ print tolower($0) }

sed:

y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/

How to randomly pick an element from an array

public static int getRandom(int[] array) {
    int rnd = new Random().nextInt(array.length);
    return array[rnd];
}

store return json value in input hidden field

It looks like the return value is in an array? That's somewhat strange... and also be aware that certain browsers will allow that to be parsed from a cross-domain request (which isn't true when you have a top-level JSON object).

Anyway, if that is an array wrapper, you'll want something like this:

$('#my-hidden-field').val(theObject[0].id);

You can later retrieve it through a simple .val() call on the same field. This honestly looks kind of strange though. The hidden field won't persist across page requests, so why don't you just keep it in your own (pseudo-namespaced) value bucket? E.g.,

$MyNamespace = $MyNamespace || {};
$MyNamespace.myKey = theObject;

This will make it available to you from anywhere, without any hacky input field management. It's also a lot more efficient than doing DOM modification for simple value storage.

How do I install Python 3 on an AWS EC2 instance?

Here are the steps I used to manually install python3 for anyone else who wants to do it as it's not super straight forward. EDIT: It's almost certainly easier to use the yum package manager (see other answers).

Note, you'll probably want to do sudo yum groupinstall 'Development Tools' before doing this otherwise pip won't install.

wget https://www.python.org/ftp/python/3.4.2/Python-3.4.2.tgz
tar zxvf Python-3.4.2.tgz
cd Python-3.4.2
sudo yum install gcc
./configure --prefix=/opt/python3
make
sudo yum install openssl-devel
sudo make install
sudo ln -s /opt/python3/bin/python3 /usr/bin/python3
python3 (should start the interpreter if it's worked (quit() to exit)

Is there a way to make a PowerShell script work by double clicking a .ps1 file?

Simple PowerShell commands to set this in the registry;

New-PSDrive -Name HKCR -PSProvider Registry -Root HKEY_CLASSES_ROOT
Set-ItemProperty -Path "HKCR:\Microsoft.PowerShellScript.1\Shell\open\command" -name '(Default)' -Value '"C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe" -noLogo -ExecutionPolicy unrestricted -file "%1"'

How do I extract specific 'n' bits of a 32-bit unsigned integer in C?

Modulus works to get bottom bits (only), although I think value & 0x1ffff expresses "take the bottom 17 bits" more directly than value % 131072, and so is easier to understand as doing that.

The top 17 bits of a 32-bit unsigned value would be value & 0xffff8000 (if you want them still in their positions at the top), or value >> 15 if you want the top 17 bits of the value in the bottom 17 bits of the result.

AngularJS does not send hidden field value

I use a classical javascript to set value to hidden input

$scope.SetPersonValue = function (PersonValue)
{
    document.getElementById('TypeOfPerson').value = PersonValue;
    if (PersonValue != 'person')
    {
        document.getElementById('Discount').checked = false;
        $scope.isCollapsed = true;
    }
    else
    {
        $scope.isCollapsed = false;
    }
}

SQL JOIN - WHERE clause vs. ON clause

  • Does not matter for inner joins

  • Matters for outer joins

    a. WHERE clause: After joining. Records will be filtered after join has taken place.

    b. ON clause - Before joining. Records (from right table) will be filtered before joining. This may end up as null in the result (since OUTER join).



Example: Consider the below tables:

    1. documents:
     | id    | name        |
     --------|-------------|
     | 1     | Document1   |
     | 2     | Document2   |
     | 3     | Document3   |
     | 4     | Document4   |
     | 5     | Document5   |


    2. downloads:
     | id   | document_id   | username |
     |------|---------------|----------|
     | 1    | 1             | sandeep  |
     | 2    | 1             | simi     |
     | 3    | 2             | sandeep  |
     | 4    | 2             | reya     |
     | 5    | 3             | simi     |

a) Inside WHERE clause:

  SELECT documents.name, downloads.id
    FROM documents
    LEFT OUTER JOIN downloads
      ON documents.id = downloads.document_id
    WHERE username = 'sandeep'

 For above query the intermediate join table will look like this.

    | id(from documents) | name         | id (from downloads) | document_id | username |
    |--------------------|--------------|---------------------|-------------|----------|
    | 1                  | Document1    | 1                   | 1           | sandeep  |
    | 1                  | Document1    | 2                   | 1           | simi     |
    | 2                  | Document2    | 3                   | 2           | sandeep  |
    | 2                  | Document2    | 4                   | 2           | reya     |
    | 3                  | Document3    | 5                   | 3           | simi     |
    | 4                  | Document4    | NULL                | NULL        | NULL     |
    | 5                  | Document5    | NULL                | NULL        | NULL     |

  After applying the `WHERE` clause and selecting the listed attributes, the result will be: 

   | name         | id |
   |--------------|----|
   | Document1    | 1  |
   | Document2    | 3  | 

b) Inside JOIN clause

  SELECT documents.name, downloads.id
  FROM documents
    LEFT OUTER JOIN downloads
      ON documents.id = downloads.document_id
        AND username = 'sandeep'

For above query the intermediate join table will look like this.

    | id(from documents) | name         | id (from downloads) | document_id | username |
    |--------------------|--------------|---------------------|-------------|----------|
    | 1                  | Document1    | 1                   | 1           | sandeep  |
    | 2                  | Document2    | 3                   | 2           | sandeep  |
    | 3                  | Document3    | NULL                | NULL        | NULL     |
    | 4                  | Document4    | NULL                | NULL        | NULL     |
    | 5                  | Document5    | NULL                | NULL        | NULL     |

Notice how the rows in `documents` that did not match both the conditions are populated with `NULL` values.

After Selecting the listed attributes, the result will be: 

   | name       | id   |
   |------------|------|
   |  Document1 | 1    |
   |  Document2 | 3    | 
   |  Document3 | NULL |
   |  Document4 | NULL | 
   |  Document5 | NULL | 

Scatter plot with error bars

To summarize Laryx Decidua's answer:

define and use a function like the following

plot.with.errorbars <- function(x, y, err, ylim=NULL, ...) {
  if (is.null(ylim))
    ylim <- c(min(y-err), max(y+err))
  plot(x, y, ylim=ylim, pch=19, ...)
  arrows(x, y-err, x, y+err, length=0.05, angle=90, code=3)
}

where one can override the automatic ylim, and also pass extra parameters such as main, xlab, ylab.

Fastest way to determine if record exists

EXISTS (or NOT EXISTS) is specially designed for checking if something exists and therefore should be (and is) the best option. It will halt on the first row that matches so it does not require a TOP clause and it does not actually select any data so there is no overhead in size of columns. You can safely use SELECT * here - no different than SELECT 1, SELECT NULL or SELECT AnyColumn... (you can even use an invalid expression like SELECT 1/0 and it will not break).

IF EXISTS (SELECT * FROM Products WHERE id = ?)
BEGIN
--do what you need if exists
END
ELSE
BEGIN
--do what needs to be done if not
END

What does "./" (dot slash) refer to in terms of an HTML file path location?

You can use the following list as quick reference:

   /   = Root directory
   .   = This location
   ..  = Up a directory
   ./  = Current directory
   ../ = Parent of current directory
   ../../ = Two directories backwards

Useful article: https://css-tricks.com/quick-reminder-about-file-paths/

How to output a comma delimited list in jinja python template?

you could also use the builtin "join" filter (http://jinja.pocoo.org/docs/templates/#join like this:

{{ users|join(', ') }}

Safest way to convert float to integer in python?

You could use the round function. If you use no second parameter (# of significant digits) then I think you will get the behavior you want.

IDLE output.

>>> round(2.99999999999)
3
>>> round(2.6)
3
>>> round(2.5)
3
>>> round(2.4)
2

How to extract the nth word and count word occurrences in a MySQL string?

Shorter option to extract the second word in a sentence:

SELECT SUBSTRING_INDEX(SUBSTRING_INDEX('THIS IS A TEST', ' ',  2), ' ', -1) as FoundText

MySQL docs for SUBSTRING_INDEX

Query-string encoding of a Javascript Object

Here's the coffeescript version of accepted answer. This might save time to someone.

serialize = (obj, prefix) ->
  str = []
  for p, v of obj
    k = if prefix then prefix + "[" + p + "]" else p
    if typeof v == "object"
      str.push(serialize(v, k))
    else
      str.push(encodeURIComponent(k) + "=" + encodeURIComponent(v))

  str.join("&")

Is it possible to print a variable's type in standard C++?

You could use a traits class for this. Something like:

#include <iostream>
using namespace std;

template <typename T> class type_name {
public:
    static const char *name;
};

#define DECLARE_TYPE_NAME(x) template<> const char *type_name<x>::name = #x;
#define GET_TYPE_NAME(x) (type_name<typeof(x)>::name)

DECLARE_TYPE_NAME(int);

int main()
{
    int a = 12;
    cout << GET_TYPE_NAME(a) << endl;
}

The DECLARE_TYPE_NAME define exists to make your life easier in declaring this traits class for all the types you expect to need.

This might be more useful than the solutions involving typeid because you get to control the output. For example, using typeid for long long on my compiler gives "x".

Scripting SQL Server permissions

Yes, you can use a script like this to generate another script

SET NOCOUNT ON;
DECLARE @NewRole varchar(100), @SourceRole varchar(100);

-- Change as needed
SELECT @SourceRole = 'Giver', @NewRole = 'Taker';

SELECT
    state_desc + ' ' + permission_name + ' ON ' + OBJECT_NAME(major_id) + ' TO ' + @NewRole
FROM
    sys.database_permissions
WHERE
    grantee_principal_id = DATABASE_PRINCIPAL_ID(@SourceRole) AND
    -- 0 = DB,  1 = object/column, 3 = schema. 1 is normally enough
    class <= 3

This is taken from my answer here

Javascript switch vs. if...else if...else

Is there a preformance difference in Javascript between a switch statement and an if...else if....else?

I don't think so, switch is useful/short if you want prevent multiple if-else conditions.

Is the behavior of switch and if...else if...else different across browsers? (FireFox, IE, Chrome, Opera, Safari)

Behavior is same across all browsers :)

Ternary operators in JavaScript without an "else"

No, it needs three operands. That's why they're called ternary operators.

However, for what you have as your example, you can do this:

if(condition) x = true;

Although it's safer to have braces if you need to add more than one statement in the future:

if(condition) { x = true; }

Edit: Now that you mention the actual code in which your question applies to:

if(!defaults.slideshowWidth)
    { defaults.slideshowWidth = obj.find('img').width()+'px'; }

What is offsetHeight, clientHeight, scrollHeight?

* offsetHeight is a measurement in pixels of the element's CSS height, including border, padding and the element's horizontal scrollbar.

* clientHeight property returns the viewable height of an element in pixels, including padding, but not the border, scrollbar or margin.

* scrollHeight value is equal to the minimum height the element would require in order to fit all the content in the viewport without using a vertical scrollbar. The height is measured in the same way as clientHeight: it includes the element's padding, but not its border, margin or horizontal scrollbar.

Same is the case for all of these with width instead of height.

What is the easiest way to parse an INI File in C++?

If you need a cross-platform solution, try Boost's Program Options library.

Is it possible to hide the cursor in a webpage using CSS or Javascript?

Pointer Lock API

While the cursor: none CSS solution is definitely a solid and easy workaround, if your actual goal is to remove the default cursor while your web application is being used, or implement your own interpretation of raw mouse movement (for FPS games, for example), you might want to consider using the Pointer Lock API instead.

You can use requestPointerLock on an element to remove the cursor, and redirect all mousemove events to that element (which you may or may not handle):

document.body.requestPointerLock();

To release the lock, you can use exitPointerLock:

document.exitPointerLock();

Additional notes

No cursor, for real

This is a very powerful API call. It not only renders your cursor invisible, but it actually removes your operating system's native cursor. You won't be able to select text, or do anything with your mouse (except listening to some mouse events in your code) until the pointer lock is released (either by using exitPointerLock or pressing ESC in some browsers).

That is, you cannot leave the window with your cursor for it to show again, as there is no cursor.

Restrictions

As mentioned above, this is a very powerful API call, and is thus only allowed to be made in response to some direct user-interaction on the web, such as a click; for example:

document.addEventListener("click", function () {
    document.body.requestPointerLock();
});

Also, requestPointerLock won't work from a sandboxed iframe unless the allow-pointer-lock permission is set.

User-notifications

Some browsers will prompt the user for a confirmation before the lock is engaged, some will simply display a message. This means pointer lock might not activate right away after the call. However, the actual activation of pointer locking can be listened to by listening to the pointerchange event on the element on which requestPointerLock was called:

document.body.addEventListener("pointerlockchange", function () {
    if (document.pointerLockElement === document.body) {
        // Pointer is now locked to <body>.
    }
});

Most browsers will only display the message once, but Firefox will occasionally spam the message on every single call. AFAIK, this can only be worked around by user-settings, see Disable pointer-lock notification in Firefox.

Listening to raw mouse movement

The Pointer Lock API not only removes the mouse, but instead redirects raw mouse movement data to the element requestPointerLock was called on. This can be listened to simply by using the mousemove event, then accessing the movementX and movementY properties on the event object:

document.body.addEventListener("mousemove", function (e) {
    console.log("Moved by " + e.movementX + ", " + e.movementY);
});

How to get the type of a variable in MATLAB?

Be careful when using the isa function. This will be true if your object is of the specified type or one of its subclasses. You have to use strcmp with the class function to test if the object is specifically that type and not a subclass.

Difference between a user and a schema in Oracle?

From WikiAnswers:

  • A schema is collection of database objects, including logical structures such as tables, views, sequences, stored procedures, synonyms, indexes, clusters, and database links.
  • A user owns a schema.
  • A user and a schema have the same name.
  • The CREATE USER command creates a user. It also automatically creates a schema for that user.
  • The CREATE SCHEMA command does not create a "schema" as it implies, it just allows you to create multiple tables and views and perform multiple grants in your own schema in a single transaction.
  • For all intents and purposes you can consider a user to be a schema and a schema to be a user.

Furthermore, a user can access objects in schemas other than their own, if they have permission to do so.

Javascript to export html table to Excel

ShieldUI's export to excel functionality should already support all special chars.

What is mutex and semaphore in Java ? What is the main difference?

A mutex is often known as a binary semaphore. Whilst a semaphore can be created with any non-zero count a mutex is conceptually a semeaphore with an upper count of 1.

What good technology podcasts are out there?

Hacker Public Radio is an excellent source of podcasts on a broad range of technical topics.

Understanding passport serialize deserialize

For anyone using Koa and koa-passport:

Know that the key for the user set in the serializeUser method (often a unique id for that user) will be stored in:

this.session.passport.user

When you set in done(null, user) in deserializeUser where 'user' is some user object from your database:

this.req.user OR this.passport.user

for some reason this.user Koa context never gets set when you call done(null, user) in your deserializeUser method.

So you can write your own middleware after the call to app.use(passport.session()) to put it in this.user like so:

app.use(function * setUserInContext (next) {
  this.user = this.req.user
  yield next
})

If you're unclear on how serializeUser and deserializeUser work, just hit me up on twitter. @yvanscher

Like Operator in Entity Framework?

I had the same problem.

For now, I've settled with client-side Wildcard/Regex filtering based on http://www.codeproject.com/Articles/11556/Converting-Wildcards-to-Regexes?msg=1423024#xx1423024xx - it's simple and works as expected.

I've found another discussion on this topic: http://forums.asp.net/t/1654093.aspx/2/10
This post looks promising if you use Entity Framework >= 4.0:

Use SqlFunctions.PatIndex:

http://msdn.microsoft.com/en-us/library/system.data.objects.sqlclient.sqlfunctions.patindex.aspx

Like this:

var q = EFContext.Products.Where(x =>
SqlFunctions.PatIndex("%CD%BLUE%", x.ProductName) > 0);

Note: this solution is for SQL-Server only, because it uses non-standard PATINDEX function.

getMinutes() 0-9 - How to display two digit numbers?

Elegant ES6 function to format a date into hh:mm:ss:

const leadingZero = (num) => `0${num}`.slice(-2);

const formatTime = (date) =>
  [date.getHours(), date.getMinutes(), date.getSeconds()]
  .map(leadingZero)
  .join(':');

How to check whether a int is not null or empty?

I think you can initialize the variables a value like -1, because if the int type variables is not initialized it can't be used. When you want to check if it is not the value you want you can check if it is -1.

Maximum call stack size exceeded error

In my case, I was sending input elements instead of their values:

$.post( '',{ registerName: $('#registerName') } )

Instead of:

$.post( '',{ registerName: $('#registerName').val() } )

This froze my Chrome tab to a point it didn't even show me the 'Wait/Kill' dialog for when the page became unresponsive...

How to filter files when using scp to copy dir recursively?

scp -i /home/<user>/.ssh/id_rsa -o "StrictHostKeyChecking=no" -rp /source/directory/path/[!.]* <target_user>@<target_system:/destination/directory/path

html select scroll bar

One options will be to show the selected option above (or below) the select list like following:

HTML

<div id="selText"><span>&nbsp;</span></div><br/>
<select size="4" id="mySelect" style="width:65px;color:#f98ad3;">
    <option value="1" selected>option 1 The Long Option</option>
    <option value="2">option 2</option>
    <option value="3">option 3</option>
    <option value="4">option 4</option>
    <option value="5">option 5 Another Longer than the Long Option ;)</option>
    <option value="6">option 6</option>
</select>

JavaScript

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js"   
  type="text/javascript"></script> 
<script type="text/javascript">
$(document).ready(function(){        
    $("select#mySelect").change(function(){
      //$("#selText").html($($(this).children("option:selected")[0]).text());
       var txt = $($(this).children("option:selected")[0]).text();
       $("<span>" + txt + "<br/></span>").appendTo($("#selText span:last"));
    });
});
</script>

PS:- Set height of div#selText otherwise it will keep shifting select list downward.

jQuery: Can I call delay() between addClass() and such?

Try this simple arrow funtion:

setTimeout( () => { $("#div").addClass("error") }, 900 );

How to build a 'release' APK in Android Studio?

AndroidStudio is alpha version for now. So you have to edit gradle build script files by yourself. Add next lines to your build.gradle

android {

    signingConfigs {

        release {

            storeFile file('android.keystore')
            storePassword "pwd"
            keyAlias "alias"
            keyPassword "pwd"
        }
    }

    buildTypes {

       release {

           signingConfig signingConfigs.release
       }
    }
}

To actually run your application at emulator or device run gradle installDebug or gradle installRelease.

You can create helloworld project from AndroidStudio wizard to see what structure of gradle files is needed. Or export gradle files from working eclipse project. Also this series of articles are helpfull http://blog.stylingandroid.com/archives/1872#more-1872

Java integer list

code that works, but output is:

10
20
30
40
50

so:

    List<Integer> myCoords = new ArrayList<Integer>();
    myCoords.add(10);
    myCoords.add(20);
    myCoords.add(30);
    myCoords.add(40);
    myCoords.add(50);
    for (Integer number : myCoords) {
        System.out.println(number);
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

Count unique values with pandas per groups

You need nunique:

df = df.groupby('domain')['ID'].nunique()

print (df)
domain
'facebook.com'    1
'google.com'      1
'twitter.com'     2
'vk.com'          3
Name: ID, dtype: int64

If you need to strip ' characters:

df = df.ID.groupby([df.domain.str.strip("'")]).nunique()
print (df)
domain
facebook.com    1
google.com      1
twitter.com     2
vk.com          3
Name: ID, dtype: int64

Or as Jon Clements commented:

df.groupby(df.domain.str.strip("'"))['ID'].nunique()

You can retain the column name like this:

df = df.groupby(by='domain', as_index=False).agg({'ID': pd.Series.nunique})
print(df)
    domain  ID
0       fb   1
1      ggl   1
2  twitter   2
3       vk   3

The difference is that nunique() returns a Series and agg() returns a DataFrame.

Can MySQL convert a stored UTC time to local timezone?

1. Correctly setup your server:

On server, su to root and do this:

# mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql mysql

(Note that the command at the end is of course mysql , and, you're sending it to a table which happens to have the same name: mysql.)

Next, you can now # ls /usr/share/zoneinfo .

Use that command to see all the time zone info on ubuntu or almost any unixish server.

(BTW that's the convenient way to find the exact official name of some time zone.)

2. It's then trivial in mysql:

For example

mysql> select ts, CONVERT_TZ(ts, 'UTC', 'Pacific/Tahiti') from example_table ;
+---------------------+-----------------------------------------+
| ts                  | CONVERT_TZ(ts, 'UTC', 'Pacific/Tahiti') |
+---------------------+-----------------------------------------+
| 2020-10-20 16:59:57 | 2020-10-20 06:59:57                     |
| 2020-10-20 17:02:59 | 2020-10-20 07:02:59                     |
| 2020-10-20 17:30:08 | 2020-10-20 07:30:08                     |
| 2020-10-20 18:36:29 | 2020-10-20 08:36:29                     |
| 2020-10-20 18:37:20 | 2020-10-20 08:37:20                     |
| 2020-10-20 18:37:20 | 2020-10-20 08:37:20                     |
| 2020-10-20 19:00:18 | 2020-10-20 09:00:18                     |
+---------------------+-----------------------------------------+

git pull error "The requested URL returned error: 503 while accessing"

Every one please avoid modifying post buffer and advising it to others. It may help in some cases but it breaks others. If you have modified your post buffer for pushing your large project. Undo it using following command. git config --global --unset http.postBuffer git config --local --unset http.postBuffer

I modified my post buffer to fix one of the issues I had with git but it was the reason for my future problems with git.

how to determine size of tablespace oracle 11g

The following query can be used to detemine tablespace and other params:

select df.tablespace_name "Tablespace",
       totalusedspace "Used MB",
       (df.totalspace - tu.totalusedspace) "Free MB",
       df.totalspace "Total MB",
       round(100 * ( (df.totalspace - tu.totalusedspace)/ df.totalspace)) "Pct. Free"
  from (select tablespace_name,
               round(sum(bytes) / 1048576) TotalSpace
          from dba_data_files 
         group by tablespace_name) df,
       (select round(sum(bytes)/(1024*1024)) totalusedspace,
               tablespace_name
          from dba_segments 
         group by tablespace_name) tu
 where df.tablespace_name = tu.tablespace_name 
   and df.totalspace <> 0;

Source: https://community.oracle.com/message/1832920

For your case if you want to know the partition name and it's size just run this query:

select owner,
       segment_name,
       partition_name,
       segment_type,
       bytes / 1024/1024 "MB" 
  from dba_segments 
 where owner = <owner_name>;

Using python PIL to turn a RGB image into a pure black and white image

As Martin Thoma has said, you need to normally apply thresholding. But you can do this using simple vectorization which will run much faster than the for loop that is used in that answer.

The code below converts the pixels of an image into 0 (black) and 1 (white).

from PIL import Image
import numpy as np
import matplotlib.pyplot as plt

#Pixels higher than this will be 1. Otherwise 0.
THRESHOLD_VALUE = 200

#Load image and convert to greyscale
img = Image.open("photo.png")
img = img.convert("L")

imgData = np.asarray(img)
thresholdedData = (imgData > THRESHOLD_VALUE) * 1.0

plt.imshow(thresholdedData)
plt.show()

Laravel stylesheets and javascript don't load for non-base routes

Just Add Another Issue:

If you want to remove /public from your project using .htaccess,

then you can use this, [Add public before /css inside asset()]

<link href="{{ asset('public/css/app.css') }}" rel="stylesheet">

[Sometimes, it is useful.]

How to automatically add user account AND password with a Bash script?

The code below worked in Ubuntu 14.04. Try before you use it in other versions/linux variants.

# quietly add a user without password
adduser --quiet --disabled-password --shell /bin/bash --home /home/newuser --gecos "User" newuser

# set password
echo "newuser:newpassword" | chpasswd