Programs & Examples On #Database independent

function declaration isn't a prototype

In C int foo() and int foo(void) are different functions. int foo() accepts an arbitrary number of arguments, while int foo(void) accepts 0 arguments. In C++ they mean the same thing. I suggest that you use void consistently when you mean no arguments.

If you have a variable a, extern int a; is a way to tell the compiler that a is a symbol that might be present in a different translation unit (C compiler speak for source file), don't resolve it until link time. On the other hand, symbols which are function names are anyway resolved at link time. The meaning of a storage class specifier on a function (extern, static) only affects its visibility and extern is the default, so extern is actually unnecessary.

I suggest removing the extern, it is extraneous and is usually omitted.

How do you write multiline strings in Go?

From String literals:

  • raw string literal supports multiline (but escaped characters aren't interpreted)
  • interpreted string literal interpret escaped characters, like '\n'.

But, if your multi-line string has to include a backquote (`), then you will have to use an interpreted string literal:

`line one
  line two ` +
"`" + `line three
line four`

You cannot directly put a backquote (`) in a raw string literal (``xx\).
You have to use (as explained in "how to put a backquote in a backquoted string?"):

 + "`" + ...

How can I restore the MySQL root user’s full privileges?

If you've deleted your root user by mistake you can do one thing:

  1. Stop MySQL service
  2. Run mysqld_safe --skip-grant-tables &
  3. Type mysql -u root -p and press enter.
  4. Enter your password
  5. At the mysql command line enter: use mysql;

Then execute this query:

insert into `user` (`Host`, `User`, `Password`, `Select_priv`, `Insert_priv`, `Update_priv`, `Delete_priv`, `Create_priv`, `Drop_priv`, `Reload_priv`, `Shutdown_priv`, `Process_priv`, `File_priv`, `Grant_priv`, `References_priv`, `Index_priv`, `Alter_priv`, `Show_db_priv`, `Super_priv`, `Create_tmp_table_priv`, `Lock_tables_priv`, `Execute_priv`, `Repl_slave_priv`, `Repl_client_priv`, `Create_view_priv`, `Show_view_priv`, `Create_routine_priv`, `Alter_routine_priv`, `Create_user_priv`, `ssl_type`, `ssl_cipher`, `x509_issuer`, `x509_subject`, `max_questions`, `max_updates`, `max_connections`, `max_user_connections`) 
values('localhost','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','','0','0','0','0');

then restart the mysqld

EDIT: October 6, 2018

In case anyone else needs this answer, I tried it today using innodb_version 5.6.36-82.0 and 10.1.24-MariaDB and it works if you REMOVE THE BACKTICKS (no single quotes either, just remove them):

insert into user (Host, User, Password, Select_priv, Insert_priv, Update_priv, Delete_priv, Create_priv, Drop_priv, Reload_priv, Shutdown_priv, Process_priv, File_priv, Grant_priv, References_priv, Index_priv, Alter_priv, Show_db_priv, Super_priv, Create_tmp_table_priv, Lock_tables_priv, Execute_priv, Repl_slave_priv, Repl_client_priv, Create_view_priv, Show_view_priv, Create_routine_priv, Alter_routine_priv, Create_user_priv, ssl_type, ssl_cipher, x509_issuer, x509_subject, max_questions, max_updates, max_connections, max_user_connections) 
values('localhost','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','','0','0','0','0');

UIView Infinite 360 degree rotation animation?

Swift 4.0

func rotateImageView()
{
    UIView.animate(withDuration: 0.3, delay: 0, options: .curveLinear, animations: {() -> Void in
        self.imageView.transform = self.imageView.transform.rotated(by: .pi / 2)
    }, completion: {(_ finished: Bool) -> Void in
        if finished {
            rotateImageView()
        }
    })
}

How to stop (and restart) the Rails Server?

I had to restart the rails application on the production so I looked for an another answer. I have found it below:

http://wiki.ocssolutions.com/Restarting_a_Rails_Application_Using_Passenger

Undefined behavior and sequence points

I am guessing there is a fundamental reason for the change, it isn't merely cosmetic to make the old interpretation clearer: that reason is concurrency. Unspecified order of elaboration is merely selection of one of several possible serial orderings, this is quite different to before and after orderings, because if there is no specified ordering, concurrent evaluation is possible: not so with the old rules. For example in:

f (a,b)

previously either a then b, or, b then a. Now, a and b can be evaluated with instructions interleaved or even on different cores.

php refresh current page?

PHP refresh current page

With PHP code:

<?php
$secondsWait = 1;
header("Refresh:$secondsWait");
echo date('Y-m-d H:i:s');
?>

Note: Remember that header() must be called before any actual output is sent, either by normal HTML tags, blank lines in a file, or from PHP.

if you send any output, you can use javascript:

<?php
echo date('Y-m-d H:i:s');
echo '<script type="text/javascript">location.reload(true);</script>';
?>

When this method receives a true value as argument, it will cause the page to always be reloaded from the server. If it is false or not specified, the browser may reload the page from its cache.

Or you can explicitly use "meta refresh" (with pure html):

<?php
$secondsWait = 1;
echo date('Y-m-d H:i:s');
echo '<meta http-equiv="refresh" content="'.$secondsWait.'">';
?>

Greetings and good code,

ASP.NET Identity DbContext confusion

If you drill down through the abstractions of the IdentityDbContext you'll find that it looks just like your derived DbContext. The easiest route is Olav's answer, but if you want more control over what's getting created and a little less dependency on the Identity packages have a look at my question and answer here. There's a code example if you follow the link, but in summary you just add the required DbSets to your own DbContext subclass.

Parsing JSON giving "unexpected token o" error

Your data is already an object. No need to parse it. The javascript interpreter has already parsed it for you.

var cur_ques_details ={"ques_id":15,"ques_title":"jlkjlkjlkjljl"};
document.write(cur_ques_details['ques_title']);

A TypeScript GUID class?

I found this https://typescriptbcl.codeplex.com/SourceControl/latest

here is the Guid version they have in case the link does not work later.

module System {
    export class Guid {
        constructor (public guid: string) {
            this._guid = guid;
        }

        private _guid: string;

        public ToString(): string {
            return this.guid;
        }

        // Static member
        static MakeNew(): Guid {
            var result: string;
            var i: string;
            var j: number;

            result = "";
            for (j = 0; j < 32; j++) {
                if (j == 8 || j == 12 || j == 16 || j == 20)
                    result = result + '-';
                i = Math.floor(Math.random() * 16).toString(16).toUpperCase();
                result = result + i;
            }
            return new Guid(result);
        }
    }
}

standard size for html newsletter template

Short answer: 400-800 pixels.

What I have read is that HTML newsletter width should be as narrow as possible without being too narrow. For instance, 400-500 pixels for a one column layout is a lower limit. Any less may look too weird.

Today's widescreen monitors allow for more horizontal pixels and most web email clients will either be of the two-column variety (Gmail) or 3-pane layout where the content window bellow the inbox list (Hotmail and Yahoo). In either case, you can be okay with 800 pixels if you're targeting the 1280 wide audience. An older or less technical audience may have older, square monitors.

There is the problem of Outlook having a three-column layout. That limits the width of your email even more. With them, you may want to go even narrower.

I just recently created a template that required an ad banner that is 730 pixels wide. It was near in the wide range, but not so much that most people could not double-click the email an open a new window in Outlook (the web email users should be okay for the most part).

Hope this advice helps.

How to install php-curl in Ubuntu 16.04

This works for me:

sudo apt-get install php5.6-curl

What's the foolproof way to tell which version(s) of .NET are installed on a production Windows Server?

OneTouch deployment will do all the detection and installation of pre-requisites. It's probably best to go with a pre-made solution than trying to roll your own. Trying to roll your own may lead to problems because whatever thing you key on may change with a hotfix or service pack. Likely Microsoft has some heuristic for determining what version is running.

Difference between <span> and <div> with text-align:center;?

Spans are inline, divs are block elements. i.e. spans are only as wide as their respective content. You can align the span inside the surrounding container (if it's a block container), but you can't align the content.

Span is primarily used for formatting purposes. If you want to arrange or position the contents, use div, p or some other block element.

Best way to test if a row exists in a MySQL table

For non-InnoDB tables you could also use the information schema tables:

http://dev.mysql.com/doc/refman/5.1/en/tables-table.html

How to display my location on Google Maps for Android API v2

Before enabling the My Location layer, you must request location permission from the user. This sample does not include a request for location permission.

To simplify, in terms of lines of code, the request for the location permit can be made using the library EasyPermissions.

Then following the example of the official documentation of The My Location Layer my code works as follows for all versions of Android that contain Google services.

  1. Create an activity that contains a map and implements the interfaces OnMyLocationClickListener y OnMyLocationButtonClickListener.
  2. Define in app/build.gradle implementation 'pub.devrel:easypermissions:2.0.1'
  3. Forward results to EasyPermissions within method onRequestPermissionsResult()

    EasyPermissions.onRequestPermissionsResult(requestCode, permissions, grantResults, this);

  4. Request permission and operate according to the user's response with requestLocationPermission()

  5. Call requestLocationPermission() and set the listeners to onMapReady().

MapsActivity.java

public class MapsActivity extends FragmentActivity implements 
    OnMapReadyCallback,
    GoogleMap.OnMyLocationClickListener,
    GoogleMap.OnMyLocationButtonClickListener {

    private final int REQUEST_LOCATION_PERMISSION = 1;

    private GoogleMap mMap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        requestLocationPermission();
        mMap.setOnMyLocationButtonClickListener(this);
        mMap.setOnMyLocationClickListener(this);
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        // Forward results to EasyPermissions
        EasyPermissions.onRequestPermissionsResult(requestCode, permissions, grantResults, this);
    }

    @SuppressLint("MissingPermission")
    @AfterPermissionGranted(REQUEST_LOCATION_PERMISSION)
    public void requestLocationPermission() {
        String[] perms = {Manifest.permission.ACCESS_FINE_LOCATION};
        if(EasyPermissions.hasPermissions(this, perms)) {
            mMap.setMyLocationEnabled(true);
            Toast.makeText(this, "Permission already granted", Toast.LENGTH_SHORT).show();
        }
        else {
            EasyPermissions.requestPermissions(this, "Please grant the location permission", REQUEST_LOCATION_PERMISSION, perms);
        }
    }

    @Override
    public boolean onMyLocationButtonClick() {
        Toast.makeText(this, "MyLocation button clicked", Toast.LENGTH_SHORT).show();
        return false;
    }

    @Override
    public void onMyLocationClick(@NonNull Location location) {
        Toast.makeText(this, "Current location:\n" + location, Toast.LENGTH_LONG).show();
    }
}

Source

"register" keyword in C?

I'm surprised that nobody mentioned that you cannot take an address of register variable, even if compiler decides to keep variable in memory rather than in register.

So using register you win nothing (anyway compiler will decide for itself where to put the variable) and lose the & operator - no reason to use it.

Performing Breadth First Search recursively

Let v be the starting vertex

Let G be the graph in question

The following is the pseudo code without using queue

Initially label v as visited as you start from v
BFS(G,v)
    for all adjacent vertices w of v in G:
        if vertex w is not visited:
            label w as visited
    for all adjacent vertices w of v in G:
        recursively call BFS(G,w)

ImageMagick security policy 'PDF' blocking conversion

This is due to a security vulnerability that has been addressed in Ghostscript 9.24 (source). If you have a newer version, you don't need this workaround anymore. On Ubuntu 19.10 with Ghostscript 6, this means:

  1. Make sure you have Ghostscript =9.24:

    gs --version
    
  2. If yes, just remove this whole following section from /etc/ImageMagick-6/policy.xml:

    <!-- disable ghostscript format types -->
    <policy domain="coder" rights="none" pattern="PS" />
    <policy domain="coder" rights="none" pattern="PS2" />
    <policy domain="coder" rights="none" pattern="PS3" />
    <policy domain="coder" rights="none" pattern="EPS" />
    <policy domain="coder" rights="none" pattern="PDF" />
    <policy domain="coder" rights="none" pattern="XPS" />
    

React-router: How to manually invoke Link?

In the version 5.x, you can use useHistory hook of react-router-dom:

// Sample extracted from https://reacttraining.com/react-router/core/api/Hooks/usehistory
import { useHistory } from "react-router-dom";

function HomeButton() {
  const history = useHistory();

  function handleClick() {
    history.push("/home");
  }

  return (
    <button type="button" onClick={handleClick}>
      Go home
    </button>
  );
}

How to Change Font Size in drawString Java

code example below:

g.setFont(new Font("TimesRoman", Font.PLAIN, 30));
g.drawString("Welcome to the Java Applet", 20 , 20);

What is referencedColumnName used for in JPA?

  • name attribute points to the column containing the asociation, i.e. column name of the foreign key
  • referencedColumnName attribute points to the related column in asociated/referenced entity, i.e. column name of the primary key

You are not required to fill the referencedColumnName if the referenced entity has single column as PK, because there is no doubt what column it references (i.e. the Address single column ID).

@ManyToOne
@JoinColumn(name="ADDR_ID")
public Address getAddress() { return address; }

However if the referenced entity has PK that spans multiple columns the order in which you specify @JoinColumn annotations has significance. It might work without the referencedColumnName specified, but that is just by luck. So you should map it like this:

@ManyToOne
@JoinColumns({
    @JoinColumn(name="ADDR_ID", referencedColumnName="ID"),
    @JoinColumn(name="ADDR_ZIP", referencedColumnName="ZIP")
})
public Address getAddress() { return address; }

or in case of ManyToMany:

@ManyToMany
@JoinTable(
    name="CUST_ADDR",
    joinColumns=
        @JoinColumn(name="CUST_ID"),
    inverseJoinColumns={
        @JoinColumn(name="ADDR_ID", referencedColumnName="ID"),
        @JoinColumn(name="ADDR_ZIP", referencedColumnName="ZIP")
    }
)

Real life example

Two queries generated by Hibernate of the same join table mapping, both without referenced column specified. Only the order of @JoinColumn annotations were changed.

/* load collection Client.emails */ 
select 
emails0_.id_client as id1_18_1_,
emails0_.rev as rev18_1_,
emails0_.id_email as id3_1_,
email1_.id_email as id1_6_0_

from client_email emails0_ 
inner join email email1_ on emails0_.id_email=email1_.id_email 

where emails0_.id_client='2' and 
emails0_.rev='18'
/* load collection Client.emails */ 
select
emails0_.rev as rev18_1_,
emails0_.id_client as id2_18_1_,
emails0_.id_email as id3_1_, 
email1_.id_email as id1_6_0_

from client_email emails0_ 
inner join email email1_ on emails0_.id_email=email1_.id_email 

where emails0_.rev='2' and 
emails0_.id_client='18'

We are querying a join table to get client's emails. The {2, 18} is composite ID of Client. The order of column names is determined by your order of @JoinColumn annotations. The order of both integers is always the same, probably sorted by hibernate and that's why proper alignment with join table columns is required and we can't or should rely on mapping order.

The interesting thing is the order of the integers does not match the order in which they are mapped in the entity - in that case I would expect {18, 2}. So it seems the Hibernate is sorting the column names before it use them in query. If this is true and you would order your @JoinColumn in the same way you would not need referencedColumnName, but I say this only for illustration.

Properly filled referencedColumnName attributes result in exactly same query without the ambiguity, in my case the second query (rev = 2, id_client = 18).

What are bitwise shift (bit-shift) operators and how do they work?

The bitwise shift operators move the bit values of a binary object. The left operand specifies the value to be shifted. The right operand specifies the number of positions that the bits in the value are to be shifted. The result is not an lvalue. Both operands have the same precedence and are left-to-right associative.

Operator     Usage

 <<           Indicates the bits are to be shifted to the left.

 >>           Indicates the bits are to be shifted to the right.

Each operand must have an integral or enumeration type. The compiler performs integral promotions on the operands, and then the right operand is converted to type int. The result has the same type as the left operand (after the arithmetic conversions).

The right operand should not have a negative value or a value that is greater than or equal to the width in bits of the expression being shifted. The result of bitwise shifts on such values is unpredictable.

If the right operand has the value 0, the result is the value of the left operand (after the usual arithmetic conversions).

The << operator fills vacated bits with zeros. For example, if left_op has the value 4019, the bit pattern (in 16-bit format) of left_op is:

0000111110110011

The expression left_op << 3 yields:

0111110110011000

The expression left_op >> 3 yields:

0000000111110110

Changing background color of text box input not working when empty

<! DOCTYPE html>
<html>
<head></head>
<body>

    <input type="text" id="subEmail">


    <script type="text/javascript">

        window.onload = function(){

        var subEmail = document.getElementById("subEmail");

        subEmail.onchange = function(){

            if(subEmail.value == "")
            {
                subEmail.style.backgroundColor = "red";
            }
            else
            {
               subEmail.style.backgroundColor = "yellow"; 
            }
        };

    };



    </script>

</body>

Search of table names

I'm using this and works fine

SELECT * FROM INFORMATION_SCHEMA.TABLES 
WHERE TABLE_NAME LIKE '%%'

Allow User to input HTML in ASP.NET MVC - ValidateInput or AllowHtml

You Can Use [AllowHtml] To Your Project For Example

 [AllowHtml]
 public string Description { get; set; }

For Use This Code To Class Library You Instal This Package

Install-Package Microsoft.AspNet.Mvc

After Use This using

using System.Web.Mvc;

How to implement Enums in Ruby?

This seems a bit superfluous, but this is a methodology that I have used a few times, especially where I am integrating with xml or some such.

#model
class Profession
  def self.pro_enum
    {:BAKER => 0, 
     :MANAGER => 1, 
     :FIREMAN => 2, 
     :DEV => 3, 
     :VAL => ["BAKER", "MANAGER", "FIREMAN", "DEV"]
    }
  end
end

Profession.pro_enum[:DEV]      #=>3
Profession.pro_enum[:VAL][1]   #=>MANAGER

This gives me the rigor of a c# enum and it is tied to the model.

Replace first occurrence of string in Python

Use re.sub directly, this allows you to specify a count:

regex.sub('', url, 1)

(Note that the order of arguments is replacement, original not the opposite, as might be suspected.)

What is the difference between prefix and postfix operators?

fun(10) returns 10. If you want it to return 11 then you need to use ++i as opposed to i++.

int fun(int i)
{
    return ++i;
}

How to start MySQL with --skip-grant-tables?

How to re-take control of the root user in MySQL.

DANGER: RISKY OPERATTION

  • Start session ssh (using root if possible).
  • Edit my.cnf file using.

    sudo vi /etc/my.cnf
    
  • Add line to mysqld block.*

    skip-grant-tables
    
  • Save and exit.

  • Restart MySQL service.

    service mysql restart
    
  • Check service status.

    service mysql status
    
  • Connect to mysql.

    mysql
    
  • Using main database.

    use mysql;
    
  • Redefine user root password.

    UPDATE user SET `authentication_string` = PASSWORD('myNuevoPassword') WHERE `User` = 'root'; 
    
  • Edit file my.cnf.

    sudo vi /etc/my.cnf
    
  • Erase line.

    skip-grant-tables
    
  • Save and exit.

  • Restart MySQL service.

    service mysqld restart
    
  • Check service status.

    service mysql status
    
  • Connect to database.

    mysql -u root -p
    
  • Type new password when prompted.

This action is very dangerous, it allows anyone to connect to all databases with no restriction without a user and password. It must be used carefully and must be reverted quickly to avoid risks.

Razor MVC Populating Javascript array with Model Array

If it is a symmetrical (rectangular) array then Try pushing into a single dimension javascript array; use razor to determine the array structure; and then transform into a 2 dimensional array.

// this just sticks them all in a one dimension array of rows * cols
var myArray = new Array();
@foreach (var d in Model.ResultArray)
{
    @:myArray.push("@d");
}

var MyA = new Array();

var rows = @Model.ResultArray.GetLength(0);
var cols = @Model.ResultArray.GetLength(1);

// now convert the single dimension array to 2 dimensions
var NewRow;
var myArrayPointer = 0;

for (rr = 0; rr < rows; rr++)
{
  NewRow = new Array();
  for ( cc = 0; cc < cols; cc++)
  {
    NewRow.push(myArray[myArrayPointer]);
    myArrayPointer++;
  }
  MyA.push(NewRow);
}

How to take input in an array + PYTHON?

data = []
n = int(raw_input('Enter how many elements you want: '))
for i in range(0, n):
    x = raw_input('Enter the numbers into the array: ')
    data.append(x)
print(data)

Now this doesn't do any error checking and it stores data as a string.

Multiple arguments to function called by pthread_create()?

I have the same question as the original poster, Michael.

However I have tried to apply the answers submitted for the original code without success

After some trial and error, here is my version of the code that works (or at least works for me!). And if you look closely, you will note that it is different to the earlier solutions posted.

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>

struct arg_struct
{
   int arg1;
   int arg2;
} *args;

void *print_the_arguments(void *arguments)
{
   struct arg_struct *args = arguments;
   printf("Thread\n");
   printf("%d\n", args->arg1);
   printf("%d\n", args->arg2);
   pthread_exit(NULL);
   return NULL;
}

int main()
{
   pthread_t some_thread;
   args = malloc(sizeof(struct arg_struct) * 1);

   args->arg1 = 5;
   args->arg2 = 7;

   printf("Before\n");
   printf("%d\n", args->arg1);
   printf("%d\n", args->arg2);
   printf("\n");


   if (pthread_create(&some_thread, NULL, &print_the_arguments, args) != 0)
   {
      printf("Uh-oh!\n");
      return -1;
   }

   return pthread_join(some_thread, NULL); /* Wait until thread is finished */
}

Return row of Data Frame based on value in a column - R

Based on the syntax provided

 Select * Where Amount = min(Amount)

You could do using:

 library(sqldf)

Using @Kara Woo's example df

  sqldf("select * from df where Amount in (select min(Amount) from df)")
  #Name Amount
 #1    B    120
 #2    E    120

Perform a Shapiro-Wilk Normality Test

Set the data as a vector and then place in the function.

Simple CSS Animation Loop – Fading In & Out "Loading" Text

As King King said, you must add the browser specific prefix. This should cover most browsers:

_x000D_
_x000D_
@keyframes flickerAnimation {_x000D_
  0%   { opacity:1; }_x000D_
  50%  { opacity:0; }_x000D_
  100% { opacity:1; }_x000D_
}_x000D_
@-o-keyframes flickerAnimation{_x000D_
  0%   { opacity:1; }_x000D_
  50%  { opacity:0; }_x000D_
  100% { opacity:1; }_x000D_
}_x000D_
@-moz-keyframes flickerAnimation{_x000D_
  0%   { opacity:1; }_x000D_
  50%  { opacity:0; }_x000D_
  100% { opacity:1; }_x000D_
}_x000D_
@-webkit-keyframes flickerAnimation{_x000D_
  0%   { opacity:1; }_x000D_
  50%  { opacity:0; }_x000D_
  100% { opacity:1; }_x000D_
}_x000D_
.animate-flicker {_x000D_
   -webkit-animation: flickerAnimation 1s infinite;_x000D_
   -moz-animation: flickerAnimation 1s infinite;_x000D_
   -o-animation: flickerAnimation 1s infinite;_x000D_
    animation: flickerAnimation 1s infinite;_x000D_
}
_x000D_
<div class="animate-flicker">Loading...</div>
_x000D_
_x000D_
_x000D_

How to style the UL list to a single line

In modern browsers you can do the following (CSS3 compliant)

_x000D_
_x000D_
ul_x000D_
{_x000D_
  display:flex;  _x000D_
  list-style:none;_x000D_
}
_x000D_
<ul>_x000D_
  <li><a href="">Item1</a></li>_x000D_
  <li><a href="">Item2</a></li>_x000D_
  <li><a href="">Item3</a></li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

Redefine tab as 4 spaces

Permanent for all users (when you alone on server):

# echo "set tabstop=4" >> /etc/vim/vimrc

Appends the setting in the config file. Normally on new server apt-get purge nano mc and all other to save your time. Otherwise, you will redefine editor in git, crontab etc.

Update Git branches from master

  1. git checkout master
  2. git pull
  3. git checkout feature_branch
  4. git rebase master
  5. git push -f

You need to do a forceful push after rebasing against master

'NOT NULL constraint failed' after adding to models.py

You must create a migration, where you will specify default value for a new field, since you don't want it to be null. If null is not required, simply add null=True and create and run migration.

live output from subprocess command

Similar to previous answers but the following solution worked for for me on windows using Python3 to provide a common method to print and log in realtime (getting-realtime-output-using-python):

def print_and_log(command, logFile):
    with open(logFile, 'wb') as f:
        command = subprocess.Popen(command, stdout=subprocess.PIPE, shell=True)

        while True:
            output = command.stdout.readline()
            if not output and command.poll() is not None:
                f.close()
                break
            if output:
                f.write(output)
                print(str(output.strip(), 'utf-8'), flush=True)
        return command.poll()

Python : Trying to POST form using requests

You can use the Session object

import requests
headers = {'User-Agent': 'Mozilla/5.0'}
payload = {'username':'niceusername','password':'123456'}

session = requests.Session()
session.post('https://admin.example.com/login.php',headers=headers,data=payload)
# the session instance holds the cookie. So use it to get/post later.
# e.g. session.get('https://example.com/profile')

Using IF..ELSE in UPDATE (SQL server 2005 and/or ACCESS 2007)

this should work

update table_name
  set column_b = case
                  when column_a = 1 then 'Y'
                  else null
                 end,
  set column_c = case
                  when column_a = 2 then 'Y'
                  else null
                 end,
  set column_d = case
                  when column_a = 3 then 'Y'
                  else null
                 end
where
 conditions

the question is why would you want to do that...you may want to rethink the data model. you can replace null with whatever you want.

Delete the first three rows of a dataframe in pandas

df.drop(df.index[[0,2]])

Pandas uses zero based numbering, so 0 is the first row, 1 is the second row and 2 is the third row.

How to call an element in a numpy array?

TL;DR:

Using slicing:

>>> import numpy as np
>>> 
>>> arr = np.array([[1,2,3,4,5],[6,7,8,9,10]])
>>> 
>>> arr[0,0]
1
>>> arr[1,1]
7
>>> arr[1,0]
6
>>> arr[1,-1]
10
>>> arr[1,-2]
9

In Long:

Hopefully this helps in your understanding:

>>> import numpy as np
>>> np.array([ [1,2,3], [4,5,6] ])
array([[1, 2, 3],
       [4, 5, 6]])
>>> x = np.array([ [1,2,3], [4,5,6] ])
>>> x[1][2] # 2nd row, 3rd column 
6
>>> x[1,2] # Similarly
6

But to appreciate why slicing is useful, in more dimensions:

>>> np.array([ [[1,2,3], [4,5,6]], [[7,8,9],[10,11,12]] ])
array([[[ 1,  2,  3],
        [ 4,  5,  6]],

       [[ 7,  8,  9],
        [10, 11, 12]]])
>>> x = np.array([ [[1,2,3], [4,5,6]], [[7,8,9],[10,11,12]] ])

>>> x[1][0][2] # 2nd matrix, 1st row, 3rd column
9
>>> x[1,0,2] # Similarly
9

>>> x[1][0:2][2] # 2nd matrix, 1st row, 3rd column
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: index 2 is out of bounds for axis 0 with size 2

>>> x[1, 0:2, 2] # 2nd matrix, 1st and 2nd row, 3rd column
array([ 9, 12])

>>> x[1, 0:2, 1:3] # 2nd matrix, 1st and 2nd row, 2nd and 3rd column
array([[ 8,  9],
       [11, 12]])

What is the meaning of curly braces?

A dictionary is something like an array that's accessed by keys (e.g. strings,...) rather than just plain sequential numbers. It contains key/value pairs, you can look up values using a key like using a phone book: key=name, number=value.

For defining such a dictionary, you use this syntax using curly braces, see also: http://wiki.python.org/moin/SimplePrograms

how to convert Lower case letters to upper case letters & and upper case letters to lower case letters

String name = "Vikash";
String upperCase = name.toUpperCase();
String lowerCase = name.toLowerCase();

Setting up foreign keys in phpMyAdmin?

InnoDB allows you to add a new foreign key constraint to a table by using ALTER TABLE:

ALTER TABLE tbl_name
    ADD [CONSTRAINT [symbol]] FOREIGN KEY
    [index_name] (index_col_name, ...)
    REFERENCES tbl_name (index_col_name,...)
    [ON DELETE reference_option]
    [ON UPDATE reference_option]

On the other hand, if MyISAM has advantages over InnoDB in your context, why would you want to create foreign key constraints at all. You can handle this on the model level of your application. Just make sure the columns which you want to use as foreign keys are indexed!

Hashing with SHA1 Algorithm in C#

This is what I went with. For those of you who want to optimize, check out https://stackoverflow.com/a/624379/991863.

    public static string Hash(string stringToHash)
    {
        using (var sha1 = new SHA1Managed())
        {
            return BitConverter.ToString(sha1.ComputeHash(Encoding.UTF8.GetBytes(stringToHash)));
        }
    }

Why isn't ProjectName-Prefix.pch created automatically in Xcode 6?

You need to create own PCH file
Add New file -> Other-> PCH file

Then add the path of this PCH file to your build setting->prefix header->path

($(SRCROOT)/filename.pch)

enter image description here

Error: Unexpected value 'undefined' imported by the module

This issue of circular dependencies of two module

Module 1:import Module 2
Module 2:import Module 1

Add common prefix to all cells in Excel

Another way to do this:

  1. Put your prefix in one column say column A in excel
  2. Put the values to which you want to add prefix in another column say column B in excel
  3. In Column C, use this formula;

"C1=A1&B1"

  1. Copy all the values in column C and paste it again in the same selection but as values only.

determine DB2 text string length

From similar question DB2 - find and compare the lentgh of the value in a table field - add RTRIM since LENGTH will return length of column definition. This should be correct:

select * from table where length(RTRIM(fieldName))=10

UPDATE 27.5.2019: maybe on older db2 versions the LENGTH function returned the length of column definition. On db2 10.5 I have tried the function and it returns data length, not column definition length:

select fieldname
, length(fieldName) len_only
, length(RTRIM(fieldName)) len_rtrim
from (values (cast('1234567890  ' as varchar(30)) )) 
as tab(fieldName)

FIELDNAME                      LEN_ONLY    LEN_RTRIM
------------------------------ ----------- -----------
1234567890                              12          10

One can test this by using this term:

where length(fieldName)!=length(rtrim(fieldName))

Facebook Graph API, how to get users email?

Assuming you've requested email permissions when the user logged in from your app and you have a valid token,

With the fetch api you can just

const token = "some_valid_token";
const response = await fetch(
        `https://graph.facebook.com/me?fields=email&access_token=${token}`
      );
const result = await response.json();

result will be:

{
    "id": "some_id",
    "email": "[email protected]"
}

id will be returned anyway.

You can add to the fields query param more stuff, but you need permissions for them if they are not on the public profile (name is public).

?fields=name,email,user_birthday&token=

https://developers.facebook.com/docs/facebook-login/permissions

How to get a substring between two strings in PHP?

function img($n,$str){

    $first=$n."tag/";
    $n+=1;
    $last=$n."tag/";
    $frm = stripos($str,$first);
    $to = stripos($str,$last);
    echo $frm."<br>";
    echo $to."<br>";
    $to=($to=="")?(strlen($str)-$frm):($to-$frm);
    $final = substr($str,$frm,$to);
    echo $to."<br>";
    echo $final."<br>";

}


$str = "1tag/Ilove.php2tag/youlike.java3tag/youlike.php";
img(1,$str);

img(2,$str);

img(3,$str);

Binary numbers in Python

I think you're confused about what binary is. Binary and decimal are just different representations of a number - e.g. 101 base 2 and 5 base 10 are the same number. The operations add, subtract, and compare operate on numbers - 101 base 2 == 5 base 10 and addition is the same logical operation no matter what base you're working in.

Double decimal formatting in Java

First import NumberFormat. Then add this:

NumberFormat currencyFormatter = NumberFormat.getCurrencyInstance();

This will give you two decimal places and put a dollar sign if it's dealing with currency.

import java.text.NumberFormat;
public class Payroll 
{
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) 
    {
    int hoursWorked = 80;
    double hourlyPay = 15.52;

    double grossPay = hoursWorked * hourlyPay;
    NumberFormat currencyFormatter = NumberFormat.getCurrencyInstance();

    System.out.println("Your gross pay is " + currencyFormatter.format(grossPay));
    }

}

Swift alert view with OK and Cancel: which button tapped?

You may want to consider using SCLAlertView, alternative for UIAlertView or UIAlertController.

UIAlertController only works on iOS 8.x or above, SCLAlertView is a good option to support older version.

github to see the details

example:

let alertView = SCLAlertView()
alertView.addButton("First Button", target:self, selector:Selector("firstButton"))
alertView.addButton("Second Button") {
    print("Second button tapped")
}
alertView.showSuccess("Button View", subTitle: "This alert view has buttons")

How can I filter a date of a DateTimeField in Django?

Hm.. My solution is working:

Mymodel.objects.filter(date_time_field__startswith=datetime.datetime(1986, 7, 28))

Conversion of Char to Binary in C

We show up two functions that prints a SINGLE character to binary.

void printbinchar(char character)
{
    char output[9];
    itoa(character, output, 2);
    printf("%s\n", output);
}

printbinchar(10) will write into the console

    1010

itoa is a library function that converts a single integer value to a string with the specified base. For example... itoa(1341, output, 10) will write in output string "1341". And of course itoa(9, output, 2) will write in the output string "1001".

The next function will print into the standard output the full binary representation of a character, that is, it will print all 8 bits, also if the higher bits are zero.

void printbincharpad(char c)
{
    for (int i = 7; i >= 0; --i)
    {
        putchar( (c & (1 << i)) ? '1' : '0' );
    }
    putchar('\n');
}

printbincharpad(10) will write into the console

    00001010

Now i present a function that prints out an entire string (without last null character).

void printstringasbinary(char* s)
{
    // A small 9 characters buffer we use to perform the conversion
    char output[9];

    // Until the first character pointed by s is not a null character
    // that indicates end of string...
    while (*s)
    {
        // Convert the first character of the string to binary using itoa.
        // Characters in c are just 8 bit integers, at least, in noawdays computers.
        itoa(*s, output, 2);

        // print out our string and let's write a new line.
        puts(output);

        // we advance our string by one character,
        // If our original string was "ABC" now we are pointing at "BC".
        ++s;
    }
}

Consider however that itoa don't adds padding zeroes, so printstringasbinary("AB1") will print something like:

1000001
1000010
110001

How to customize message box

You can't restyle the default MessageBox as that's dependant on the current Windows OS theme, however you can easily create your own MessageBox. Just add a new form (i.e. MyNewMessageBox) to your project with these settings:

FormBorderStyle    FixedToolWindow
ShowInTaskBar      False
StartPosition      CenterScreen

To show it use myNewMessageBoxInstance.ShowDialog();. And add a label and buttons to your form, such as OK and Cancel and set their DialogResults appropriately, i.e. add a button to MyNewMessageBox and call it btnOK. Set the DialogResult property in the property window to DialogResult.OK. When that button is pressed it would return the OK result:

MyNewMessageBox myNewMessageBoxInstance = new MyNewMessageBox();
DialogResult result = myNewMessageBoxInstance.ShowDialog();
if (result == DialogResult.OK)
{
    // etc
}

It would be advisable to add your own Show method that takes the text and other options you require:

public DialogResult Show(string text, Color foreColour)
{
     lblText.Text = text;
     lblText.ForeColor = foreColour;
     return this.ShowDialog();
}

Best way to create enum of strings?

Either set the enum name to be the same as the string you want or, more generally,you can associate arbitrary attributes with your enum values:

enum Strings {
   STRING_ONE("ONE"), STRING_TWO("TWO");
   private final String stringValue;
   Strings(final String s) { stringValue = s; }
   public String toString() { return stringValue; }
   // further methods, attributes, etc.
}

It's important to have the constants at the top, and the methods/attributes at the bottom.

ln (Natural Log) in Python

math.log is the natural logarithm:

From the documentation:

math.log(x[, base]) With one argument, return the natural logarithm of x (to base e).

Your equation is therefore:

n = math.log((1 + (FV * r) / p) / math.log(1 + r)))

Note that in your code you convert n to a str twice which is unnecessary

PHP send mail to multiple email addresses

Programmatically sending an submitted form to multiple email address is a possible thing, however the best practice for this is by creating a mailing list. On the code the list address will be place and any change or update on email addresses to the recipients list can be done without changing in the code.

Run javascript script (.js file) in mongodb including another file inside js

Use Load function

load(filename)

You can directly call any .js file from the mongo shell, and mongo will execute the JavaScript.

Example : mongo localhost:27017/mydb myfile.js

This executes the myfile.js script in mongo shell connecting to mydb database with port 27017 in localhost.

For loading external js you can write

load("/data/db/scripts/myloadjs.js")

Suppose we have two js file myFileOne.js and myFileTwo.js

myFileOne.js

print('From file 1');
load('myFileTwo.js');     // Load other js file .

myFileTwo.js

print('From file 2');

MongoShell

>mongo myFileOne.js

Output

From file 1
From file 2

How to add elements of a string array to a string array list?

You should instantiate your ArrayList before trying to add items:

private List<String> species = new ArrayList<String>();

Android : Check whether the phone is dual SIM

I was taking a look at the call logs and I noticed that apart from the usual fields in the contents of managedCursor, we have a column "simid" in Dual SIM phones (I checked on Xolo A500s Lite), so as to tag each call in the call log with a SIM. This value is either 1 or 2, most probably denoting SIM1/SIM2.

managedCursor = context.getContentResolver().query(contacts, null, null, null, null);
managedCursor.moveToNext();        
for(int i=0;i<managedCursor.getColumnCount();i++)
{//for dual sim phones
    if(managedCursor.getColumnName(i).toLowerCase().equals("simid"))
        indexSIMID=i;
}

I did not find this column in a single SIM phone (I checked on Xperia L).

So although I don't think this is a foolproof way to check for dual SIM nature, I am posting it here because it could be useful to someone.

How do I calculate someone's age based on a DateTime type birthday?

I would simply do this:

DateTime birthDay = new DateTime(1990, 05, 23);
DateTime age = DateTime.Now - birthDay;

This way you can calculate the exact age of a person, down to the millisecond if you want.

How can I delay a method call for 1 second?

NOTE: this will pause your whole thread, not just the one method.
Make a call to sleep/wait/halt for 1000 ms just before calling your method?

Sleep(1000); // does nothing the next 1000 mSek

Methodcall(params); // now do the real thing

Edit: The above answer applies to the general question "How can I delay a method call for 1 second?", which was the question asked at the time of the answer (infact the answer was given within 7 minutes of the original question :-)). No Info was given about the language at that time, so kindly stop bitching about the proper way of using sleep i XCode og the lack of classes...

How to check if IsNumeric

You should use TryParse method which Converts the string representation of a number to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded.

    int intParsed;
    if(int.TryParse(txtMyText.Text.Trim(),out intParsed))
    {
        // perform your code
    }

How do you detect where two line segments intersect?

I think there is a much much simpler solution for this problem. I came up with another idea today and it seems to work just fine (at least in 2D for now). All you have to do, is to calculate the intersection between two lines, then check if the calculated intersection point is within the boundig boxes of both line segments. If it is, the line segments intersect. That's it.

EDIT:

This is how I calculate the intersection (I don't know anymore where I found this code snippet)

Point3D

comes from

System.Windows.Media.Media3D

public static Point3D? Intersection(Point3D start1, Point3D end1, Point3D start2, Point3D end2) {

        double a1 = end1.Y - start1.Y;
        double b1 = start1.X - end1.X;
        double c1 = a1 * start1.X + b1 * start1.Y;

        double a2 = end2.Y - start2.Y;
        double b2 = start2.X - end2.X;
        double c2 = a2 * start2.X + b2 * start2.Y;

        double det = a1 * b2 - a2 * b1;
        if (det == 0) { // lines are parallel
            return null;
        }

        double x = (b2 * c1 - b1 * c2) / det;
        double y = (a1 * c2 - a2 * c1) / det;

        return new Point3D(x, y, 0.0);
    }

and this is my (simplified for the purpose of the answer) BoundingBox class:

public class BoundingBox {
    private Point3D min = new Point3D();
    private Point3D max = new Point3D();

    public BoundingBox(Point3D point) {
        min = point;
        max = point;
    }

    public Point3D Min {
        get { return min; }
        set { min = value; }
    }

    public Point3D Max {
        get { return max; }
        set { max = value; }
    }

    public bool Contains(BoundingBox box) {
        bool contains =
            min.X <= box.min.X && max.X >= box.max.X &&
            min.Y <= box.min.Y && max.Y >= box.max.Y &&
            min.Z <= box.min.Z && max.Z >= box.max.Z;
        return contains;
    }

    public bool Contains(Point3D point) {
        return Contains(new BoundingBox(point));
    }

}

Groovy Shell warning "Could not open/create prefs root node ..."

I was getting the following message:

Could not open/create prefs root node Software\JavaSoft\Prefs at root 0x80000002

and it was gone after creating one of these registry keys, mine is 64 bit so I tried only that.

32 bit Windows
HKEY_LOCAL_MACHINE\Software\JavaSoft\Prefs

64 bit Windows
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\JavaSoft\Prefs

How to append multiple items in one line in Python

You could also:

newlist += mylist[i:i+22]

Why do I get a "permission denied" error while installing a gem?

Your Ruby is installed in /usr/local/Cellar/ruby/....

That is a restricted path and can only be written to when you use elevated privileges, either by running as root or by using sudo. I won't recommend you run things as root since you don't understand how paths and permissions work. You can use sudo gem install jekyll, which will temporarily elevate your permissions, giving your command the rights needed to write to that directory.

However, I'd recommend you give serious thought into NOT doing that, and instead use your RVM to install Ruby into your own home directory, where you'll automatically be able to install Rubies and gems without permission issues. See the directions for installing into a local RVM sandbox in "Single-User installations".

Because you have RVM in your ~/.bash_profile, but it doesn't show up in your Gem environment listing, I suspect you either haven't followed the directions for installing RVM correctly, or you haven't used the all-important command:

rvm use 2.0.0 --default

to configure a default Ruby.

For most users, the "Single-User installation" is the way to go. If you have to use sudo with that configuration you've done something wrong.

Git for beginners: The definitive practical guide

How can I create a branch on a remote repository?

Assuming that you have cloned your remote repository from some single remote repository.

# create a new branch locally
git branch name_of_branch
git checkout name_of_branch
# edit/add/remove files    
# ... 
# Commit your changes locally
git add fileName
git commit -m Message
# push changes and new branch to remote repository:
git push origin name_of_branch:name_of_branch

onclick="location.href='link.html'" does not load page in Safari

Give this a go:

<option onclick="parent.location='#5.2'">Bookmark 2</option>

How to solve COM Exception Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))?

I ran into the same issue using a COM class, i.e. 'Class not registered exception' at runtime. For me I was able to resolve by going to the app.config file and change the 'startup' and 'supportedRuntime' elements to something like:

<configuration>
  <startup useLegacyV2RuntimeActivationPolicy="true">
    <supportedRuntime version="v4.0"/>
  </startup>
</configuration>

You can read more about the details here http://stackoverflow.com/questions/1604663/

and here https://msdn.microsoft.com/en-us/library/w4atty68(v=vs.110).aspx

I should note I am running Visual Studio 2017. Target cpu = x86 Embed Interop Type = true (in the properties window)

Automatically open Chrome developer tools when new tab/new window is opened

I came here looking for a similar solution. I really wanted to see the chrome output for the pageload from a new tab. (a form submission in my case) The solution I actually used was to modify the form target attribute so that the form submission would occur in the current tab. I was able to capture the network request. Problem Solved!

Adding external library in Android studio

To reference an external lib project without copy, just do this: - Insert this 2 lines on setting.gradle:

  include ':your-lib-name'
  project(':your-lib-name').projectDir = new File('/path-to-your-lib/your-lib-name)

Insert this line on on dependencies part of build.gradle file:

compile project(':your-lib-name')

Sync project

No authenticationScheme was specified, and there was no DefaultChallengeScheme found with default authentification and custom authorization

Do not use authorization instead of authentication. I should get whole access to service all clients with header. The working code is :

public class TokenAuthenticationHandler : AuthenticationHandler<TokenAuthenticationOptions> 
{
    public IServiceProvider ServiceProvider { get; set; }

    public TokenAuthenticationHandler (IOptionsMonitor<TokenAuthenticationOptions> options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock, IServiceProvider serviceProvider) 
        : base (options, logger, encoder, clock) 
    {
        ServiceProvider = serviceProvider;
    }

    protected override Task<AuthenticateResult> HandleAuthenticateAsync () 
    {
        var headers = Request.Headers;
        var token = "X-Auth-Token".GetHeaderOrCookieValue (Request);

        if (string.IsNullOrEmpty (token)) {
            return Task.FromResult (AuthenticateResult.Fail ("Token is null"));
        }           

        bool isValidToken = false; // check token here

        if (!isValidToken) {
            return Task.FromResult (AuthenticateResult.Fail ($"Balancer not authorize token : for token={token}"));
        }

        var claims = new [] { new Claim ("token", token) };
        var identity = new ClaimsIdentity (claims, nameof (TokenAuthenticationHandler));
        var ticket = new AuthenticationTicket (new ClaimsPrincipal (identity), this.Scheme.Name);
        return Task.FromResult (AuthenticateResult.Success (ticket));
    }
}

Startup.cs :

#region Authentication
services.AddAuthentication (o => {
    o.DefaultScheme = SchemesNamesConst.TokenAuthenticationDefaultScheme;
})
.AddScheme<TokenAuthenticationOptions, TokenAuthenticationHandler> (SchemesNamesConst.TokenAuthenticationDefaultScheme, o => { });
#endregion

And mycontroller.cs

[Authorize(AuthenticationSchemes = SchemesNamesConst.TokenAuthenticationDefaultScheme)]
public class MainController : BaseController
{ ... }

I can't find TokenAuthenticationOptions now, but it was empty. I found the same class PhoneNumberAuthenticationOptions :

public class PhoneNumberAuthenticationOptions : AuthenticationSchemeOptions
{
    public Regex PhoneMask { get; set; }// = new Regex("7\\d{10}");
}

You should define static class SchemesNamesConst. Something like:

public static class SchemesNamesConst
{
    public const string TokenAuthenticationDefaultScheme = "TokenAuthenticationScheme";
}

cast or convert a float to nvarchar?

Do not use floats to store fixed-point, accuracy-required data. This example shows how to convert a float to NVARCHAR(50) properly, while also showing why it is a bad idea to use floats for precision data.

create table #f ([Column_Name] float)
insert #f select 9072351234
insert #f select 907235123400000000000

select
    cast([Column_Name] as nvarchar(50)),
    --cast([Column_Name] as int), Arithmetic overflow
    --cast([Column_Name] as bigint), Arithmetic overflow
    CAST(LTRIM(STR([Column_Name],50)) AS NVARCHAR(50))
from #f

Output

9.07235e+009    9072351234
9.07235e+020    907235123400000010000

You may notice that the 2nd output ends with '10000' even though the data we tried to store in the table ends with '00000'. It is because float datatype has a fixed number of significant figures supported, which doesn't extend that far.

Exporting functions from a DLL with dllexport

If you want plain C exports, use a C project not C++. C++ DLLs rely on name-mangling for all the C++isms (namespaces etc...). You can compile your code as C by going into your project settings under C/C++->Advanced, there is an option "Compile As" which corresponds to the compiler switches /TP and /TC.

If you still want to use C++ to write the internals of your lib but export some functions unmangled for use outside C++, see the second section below.

Exporting/Importing DLL Libs in VC++

What you really want to do is define a conditional macro in a header that will be included in all of the source files in your DLL project:

#ifdef LIBRARY_EXPORTS
#    define LIBRARY_API __declspec(dllexport)
#else
#    define LIBRARY_API __declspec(dllimport)
#endif

Then on a function that you want to be exported you use LIBRARY_API:

LIBRARY_API int GetCoolInteger();

In your library build project create a define LIBRARY_EXPORTS this will cause your functions to be exported for your DLL build.

Since LIBRARY_EXPORTS will not be defined in a project consuming the DLL, when that project includes the header file of your library all of the functions will be imported instead.

If your library is to be cross-platform you can define LIBRARY_API as nothing when not on Windows:

#ifdef _WIN32
#    ifdef LIBRARY_EXPORTS
#        define LIBRARY_API __declspec(dllexport)
#    else
#        define LIBRARY_API __declspec(dllimport)
#    endif
#elif
#    define LIBRARY_API
#endif

When using dllexport/dllimport you do not need to use DEF files, if you use DEF files you do not need to use dllexport/dllimport. The two methods accomplish the same task different ways, I believe that dllexport/dllimport is the recommended method out of the two.

Exporting unmangled functions from a C++ DLL for LoadLibrary/PInvoke

If you need this to use LoadLibrary and GetProcAddress, or maybe importing from another language (i.e PInvoke from .NET, or FFI in Python/R etc) you can use extern "C" inline with your dllexport to tell the C++ compiler not to mangle the names. And since we are using GetProcAddress instead of dllimport we don't need to do the ifdef dance from above, just a simple dllexport:

The Code:

#define EXTERN_DLL_EXPORT extern "C" __declspec(dllexport)

EXTERN_DLL_EXPORT int getEngineVersion() {
  return 1;
}

EXTERN_DLL_EXPORT void registerPlugin(Kernel &K) {
  K.getGraphicsServer().addGraphicsDriver(
    auto_ptr<GraphicsServer::GraphicsDriver>(new OpenGLGraphicsDriver())
  );
}

And here's what the exports look like with Dumpbin /exports:

  Dump of file opengl_plugin.dll

  File Type: DLL

  Section contains the following exports for opengl_plugin.dll

    00000000 characteristics
    49866068 time date stamp Sun Feb 01 19:54:32 2009
        0.00 version
           1 ordinal base
           2 number of functions
           2 number of names

    ordinal hint RVA      name

          1    0 0001110E getEngineVersion = @ILT+265(_getEngineVersion)
          2    1 00011028 registerPlugin = @ILT+35(_registerPlugin)

So this code works fine:

m_hDLL = ::LoadLibrary(T"opengl_plugin.dll");

m_pfnGetEngineVersion = reinterpret_cast<fnGetEngineVersion *>(
  ::GetProcAddress(m_hDLL, "getEngineVersion")
);
m_pfnRegisterPlugin = reinterpret_cast<fnRegisterPlugin *>(
  ::GetProcAddress(m_hDLL, "registerPlugin")
);

codeigniter, result() vs. result_array()

result_array() is faster, result() is easier

What is the difference between float and double?

Type float, 32 bits long, has a precision of 7 digits. While it may store values with very large or very small range (+/- 3.4 * 10^38 or * 10^-38), it has only 7 significant digits.

Type double, 64 bits long, has a bigger range (*10^+/-308) and 15 digits precision.

Type long double is nominally 80 bits, though a given compiler/OS pairing may store it as 12-16 bytes for alignment purposes. The long double has an exponent that just ridiculously huge and should have 19 digits precision. Microsoft, in their infinite wisdom, limits long double to 8 bytes, the same as plain double.

Generally speaking, just use type double when you need a floating point value/variable. Literal floating point values used in expressions will be treated as doubles by default, and most of the math functions that return floating point values return doubles. You'll save yourself many headaches and typecastings if you just use double.

How to check a channel is closed or not without reading it?

I have had this problem frequently with multiple concurrent goroutines.

It may or may not be a good pattern, but I define a a struct for my workers with a quit channel and field for the worker state:

type Worker struct {
    data chan struct
    quit chan bool
    stopped bool
}

Then you can have a controller call a stop function for the worker:

func (w *Worker) Stop() {
    w.quit <- true
    w.stopped = true
}

func (w *Worker) eventloop() {
    for {
        if w.Stopped {
            return
        }
        select {
            case d := <-w.data:
                //DO something
                if w.Stopped {
                    return
                }
            case <-w.quit:
                return
        }
    }
}

This gives you a pretty good way to get a clean stop on your workers without anything hanging or generating errors, which is especially good when running in a container.

Find string between two substrings

To extract STRING, try:

myString = '123STRINGabc'
startString = '123'
endString = 'abc'

mySubString=myString[myString.find(startString)+len(startString):myString.find(endString)]

Where should I put the CSS and Javascript code in an HTML webpage?

In my opinion best way is 1) place the CSS file in the header part in between head tag reason is first page show the view for that css require 2)and all js file should place before the body closing tag. reason is after all component display js can apply

Setting environment variables via launchd.conf no longer works in OS X Yosemite/El Capitan/macOS Sierra/Mojave?

I added the variables in the ~/.bash_profile in the following way. After you are done restart/log out and log in

export M2_HOME=/Users/robin/softwares/apache-maven-3.2.3
export ANT_HOME=/Users/robin/softwares/apache-ant-1.9.4
launchctl setenv M2_HOME $M2_HOME
launchctl setenv ANT_HOME $ANT_HOME
export PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/Users/robin/softwares/apache-maven-3.2.3/bin:/Users/robin/softwares/apache-ant-1.9.4/bin
launchctl setenv PATH $PATH

NOTE: without restart/log out and log in you can apply these changes using;

source ~/.bash_profile

How to find SQL Server running port?

SQL Server 2000 Programs | MS SQL Server | Client Network Utility | Select TCP_IP then Properties

SQL Server 2005 Programs | SQL Server | SQL Server Configuration Manager | Select Protocols for MSSQLSERVER or select Client Protocols and right click on TCP/IP

Java: String - add character n-times

Its better to use StringBuilder instead of String because String is an immutable class and it cannot be modified once created: in String each concatenation results in creating a new instance of the String class with the modified string.

How to call JavaScript function instead of href in HTML

Your should also separate the javascript from the HTML.
HTML:

<a href="#" id="function-click"><img title="next page" alt="next page" src="/themes/me/img/arrn.png"></a>

javascript:

myLink = document.getElementById('function-click');
myLink.onclick = ShowOld(2367,146986,2);

Just make sure the last line in the ShowOld function is:

return false;

as this will stop the link from opening in the browser.

phpmyadmin logs out after 1440 secs

You just Increase the phpMyAdmin Session Timeout, open config.inc.php in the root phpMyAdmin directory and add this line.

from the wamp folder path wamp\apps\phpmyadmin4.0.4\config.inc.php

$cfg['LoginCookieValidity'] = <your_timeout>;

Example

$cfg['LoginCookieValidity'] = '1440';

Note: short cookie lifetime is all well and good for the development server not for your production server.

How to get the current TimeStamp?

Since Qt 5.8, we now have QDateTime::currentSecsSinceEpoch() to deliver the seconds directly, a.k.a. as real Unix timestamp. So, no need to divide the result by 1000 to get seconds anymore.

Credits: also posted as comment to this answer. However, I think it is easier to find if it is a separate answer.

How to change node.js's console font color?

var colorSet = {
    Reset: "\x1b[0m",
    Red: "\x1b[31m",
    Green: "\x1b[32m",
    Yellow: "\x1b[33m",
    Blue: "\x1b[34m",
    Magenta: "\x1b[35m"
};

var funcNames = ["info", "log", "warn", "error"];
var colors = [colorSet.Green, colorSet.Blue, colorSet.Yellow, colorSet.Red];

for (var i = 0; i < funcNames.length; i++) {
    let funcName = funcNames[i];
    let color = colors[i];
    let oldFunc = console[funcName];
    console[funcName] = function () {
        var args = Array.prototype.slice.call(arguments);
        if (args.length) {
            args = [color + args[0]].concat(args.slice(1), colorSet.Reset);
        }
        oldFunc.apply(null, args);
    };
}

// Test:
console.info("Info is green.");
console.log("Log is blue.");
console.warn("Warn is orange.");
console.error("Error is red.");
console.info("--------------------");
console.info("Formatting works as well. The number = %d", 123);

Using Panel or PlaceHolder

I weird bug* in visual studio 2010, if you put controls inside a Placeholder it does not render them in design view mode.

This is especially true for Hidenfields and Empty labels.

I would love to use placeholders instead of panels but I hate the fact I cant put other controls inside placeholders at design time in the GUI.

How to create a date and time picker in Android?

combined DatePicker and TimePicker in DialogFragment for Android

I created a library to do this. It also has customizable colors!

It's very simple to use.

First you create a listener:

private SlideDateTimeListener listener = new SlideDateTimeListener() {

    @Override
    public void onDateTimeSet(Date date)
    {
        // Do something with the date. This Date object contains
        // the date and time that the user has selected.
    }

    @Override
    public void onDateTimeCancel()
    {
        // Overriding onDateTimeCancel() is optional.
    }
};

Then you create and show the dialog:

new SlideDateTimePicker.Builder(getSupportFragmentManager())
    .setListener(listener)
    .setInitialDate(new Date())
    .build()
    .show();

I hope you find it useful.

Extract names of objects from list

You can just use:

> names(LIST)
[1] "A" "B"

Obviously the names of the first element is just

> names(LIST)[1]
[1] "A"

Facebook API error 191

Working locally... I couldn't get the feeds api to work, but the share api worked pretty much straight away with no problems.

window.close() doesn't work - Scripts may close only the windows that were opened by it

Error messages don't get any clearer than this:

"Scripts may close only the windows that were opened by it."

If your script did not initiate opening the window (with something like window.open), then the script in that window is not allowed to close it. Its a security to prevent a website taking control of your browser and closing windows.

Downloading Java JDK on Linux via wget is shown license page instead

Instead of using for every new Java version a new link or changing existing scripts, I was looking for a more generic way to automate the download of the required Java packages and later installation via yum localinstall ${JAVA_ENVIRONMENT}-${JAVA_VERSION}-linux-x64.rpm.

I've used a somehow trivial approach similar to manual/user action to find the package and to download it. I am also pretty sure that one will find a more elegant way to do it by using other tools like egrep, awk, etc.., so leave it as an example here:

#!/bin/bash

### Proxy settings
# If there is a company proxy 

PROXY="my.proxy.local:8080"
PROXY_TYPE="--proxy-ntlm" # or leave empty with ""
USER="user"
PASS='pass'

### Find out the links to JRE and JDK 
# To do so, got to the page http://www.oracle.com/technetwork/java/javase/downloads/

BASE_URL="technetwork/java/javase/downloads"

# Put the whole page into a single string/line

BASE_URL_OUTPUT="$(curl -s -k ${PROXY_TYPE} -x "http://${USER}:${PASS}@${PROXY}" -L0 http://www.oracle.com/${BASE_URL}/)"

# Define the environments to download 

JAVA_ENVIRONMENTS=("JRE" "JDK") # ! yet "SERVER-JRE"

for JAVA_ENVIRONMENT in "${JAVA_ENVIRONMENTS[@]}"
do

echo
echo "JAVA_ENVIRONMENT="$JAVA_ENVIRONMENT
echo

for (( JAVA_BASE_VERSION = 8; JAVA_BASE_VERSION <= 10; JAVA_BASE_VERSION += 2 ))  
do

echo "JAVA_BASE_VERSION="$JAVA_BASE_VERSION

### "Read the page"
# and follow the links for the package interested in 

DOWNLOAD_SITE="$(echo $BASE_URL_OUTPUT | grep -m 1 -io "${JAVA_ENVIRONMENT}${JAVA_BASE_VERSION}-downloads-[0-9]*.html" -- | tail -1)"
echo "DOWNLOAD_SITE="$DOWNLOAD_SITE

### Gather the necessary download links
# To do so, following the link to the download site
# reading and accept the license 
# 
# ... the greedy regular expression is to address the different syntax of the links
# and already prepared for OR .gz files 

DOWNLOAD_LINK_OUTPUT="$(curl -s -k ${PROXY_TYPE} -x "http://${USER}:${PASS}@${PROXY}" -L -j -H "Cookie: oraclelicense=accept-securebackup-cookie" http://www.oracle.com/${BASE_URL}/${DOWNLOAD_SITE} |  grep -io "filepath.*${JAVA_ENVIRONMENT}-[${JAVA_BASE_VERSION}].*linux[-_]x64[._].*\(rpm\)" -- | cut -d '"' -f 3 | tail -1)"

# and echo out the link

echo "DOWNLOAD_LINK_OUTPUT="$DOWNLOAD_LINK_OUTPUT

done

done

Since the download links are available now, one may proceed further with wget or curl.

Simple PHP calculator

<?php 
$result = "";
class calculator
{
    var $a;
    var $b;

    function checkopration($oprator)
    {
        switch($oprator)
        {
            case '+':
            return $this->a + $this->b;
            break;

            case '-':
            return $this->a - $this->b;
            break;

            case '*':
            return $this->a * $this->b;
            break;

            case '/':
            return $this->a / $this->b;
            break;

            default:
            return "Sorry No command found";
        }   
    }
    function getresult($a, $b, $c)
    {
        $this->a = $a;
        $this->b = $b;
        return $this->checkopration($c);
    }
}

$cal = new calculator();
if(isset($_POST['submit']))
{   
    $result = $cal->getresult($_POST['n1'],$_POST['n2'],$_POST['op']);
}
?>

<form method="post">
<table align="center">
    <tr>
        <td><strong><?php echo $result; ?><strong></td>
    </tr>
    <tr>
        <td>Enter 1st Number</td>
        <td><input type="text" name="n1"></td>
    </tr>

    <tr>
        <td>Enter 2nd Number</td>
        <td><input type="text" name="n2"></td>
    </tr>

    <tr>
        <td>Select Oprator</td>
        <td><select name="op">
            <option value="+">+</option>
            <option value="-">-</option>
            <option value="*">*</option>
            <option value="/">/</option>
        </select></td>
    </tr>

    <tr>
        <td></td>
        <td><input type="submit" name="submit" value="                =                "></td>
    </tr>

</table>
</form>

Find Number of CPUs and Cores per CPU using Command Prompt

In order to check the absence of physical sockets run:

wmic cpu get SocketDesignation

Disabling SSL Certificate Validation in Spring RestTemplate

What you need to add is a custom HostnameVerifier class bypasses certificate verification and returns true

HttpsURLConnection.setDefaultHostnameVerifier(new HostnameVerifier() {
            public boolean verify(String hostname, SSLSession session) {
                return true;
            }
        });

This needs to be placed appropriately in your code.

ORA-00907: missing right parenthesis

Firstly, in histories_T, you are referencing table T_customer (should be T_customers) and secondly, you are missing the FOREIGN KEY clause that REFERENCES orders; which is not being created (or dropped) with the code you provided.

There may be additional errors as well, and I admit Oracle has never been very good at describing the cause of errors - "Mutating Tables" is a case in point.

Let me know if there additional problems you are missing.

Java Regex Replace with Capturing Group

Java 9 offers a Matcher.replaceAll() that accepts a replacement function:

resultString = regexMatcher.replaceAll(
        m -> String.valueOf(Integer.parseInt(m.group()) * 3));

What is CMake equivalent of 'configure --prefix=DIR && make all install '?

Note that in both CMake and Autotools you don't always have to set the installation path at configure time. You can use DESTDIR at install time (see also here) instead as in:

make DESTDIR=<installhere> install

See also this question which explains the subtle difference between DESTDIR and PREFIX.

This is intended for staged installs and to allow for storing programs in a different location from where they are run e.g. /etc/alternatives via symbolic links.

However, if your package is relocatable and doesn't need any hard-coded (prefix) paths set via the configure stage you may be able to skip it. So instead of:

cmake -DCMAKE_INSTALL_PREFIX=/usr . && make all install

you would run:

cmake . && make DESTDIR=/usr all install

Note that, as user7498341 points out, this is not appropriate for cases where you really should be using PREFIX.

Disable same origin policy in Chrome

EDIT 3: Seems that the extension no longer exists... Normally to get around CORS these days I set up another version of Chrome with a separate directory or I use Firefox with https://addons.mozilla.org/en-US/firefox/addon/cors-everywhere/ instead.

EDIT 2: I can no longer get this to work consistently.

EDIT: I tried using the just the other day for another project and it stopped working. Uninstalling and reinstalling the extension fixed it (to reset the defaults).

Original Answer:

I didn't want to restart Chrome and disable my web security (because I was browsing while developing) and stumbled onto this Chrome extension.

Chrome Web Store Allow-Control-Allow-Origin: *
(https://chrome.google.com/webstore/detail/allow-control-allow-origi/nlfbmbojpeacfghkpbjhddihlkkiljbi?hl=en)

Basically it's a little toggle switch to toggle on and off the Allow-Access-Origin-Control check. Works perfectly for me for what I'm doing.

git diff file against its last change

One of the ways to use git diff is:

git diff <commit> <path>

And a common way to refer one commit of the last commit is as a relative path to the actual HEAD. You can reference previous commits as HEAD^ (in your example this will be 123abc) or HEAD^^ (456def in your example), etc ...

So the answer to your question is:

git diff HEAD^^ myfile

How to get the Mongo database specified in connection string in C#

Update:

MongoServer.Create is obsolete now (thanks to @aknuds1). Instead this use following code:

var _server = new MongoClient(connectionString).GetServer();

It's easy. You should first take database name from connection string and then get database by name. Complete example:

var connectionString = "mongodb://localhost:27020/mydb";

//take database name from connection string
var _databaseName = MongoUrl.Create(connectionString).DatabaseName;
var _server = MongoServer.Create(connectionString);

//and then get database by database name:
_server.GetDatabase(_databaseName);

Important: If your database and auth database are different, you can add a authSource= query parameter to specify a different auth database. (thank you to @chrisdrobison)

From docs:

NOTE If you are using the database segment as the initial database to use, but the username and password specified are defined in a different database, you can use the authSource option to specify the database in which the credential is defined. For example, mongodb://user:pass@hostname/db1?authSource=userDb would authenticate the credential against the userDb database instead of db1.

How to Convert string "07:35" (HH:MM) to TimeSpan

You can convert the time using the following code.

TimeSpan _time = TimeSpan.Parse("07:35");

But if you want to get the current time of the day you can use the following code:

TimeSpan _CurrentTime = DateTime.Now.TimeOfDay;

The result will be:

03:54:35.7763461

With a object cantain the Hours, Minutes, Seconds, Ticks and etc.

Convert floats to ints in Pandas?

>>> import pandas as pd
>>> right = pd.DataFrame({'C': [1.002, 2.003], 'D': [1.009, 4.55], 'key': ['K0', 'K1']})
>>> print(right)
           C      D key
    0  1.002  1.009  K0
    1  2.003  4.550  K1
>>> right['C'] = right.C.astype(int)
>>> print(right)
       C      D key
    0  1  1.009  K0
    1  2  4.550  K1

Tomcat started in Eclipse but unable to connect to http://localhost:8085/

You can change the port number:

Open the server tab in eclipse -> right click open click on open---->you can change the port number.

Run the application with http://localhost:8080/Applicationname it will give output and also check http://localhost:8080/Applicationname/index.jsp

Measuring function execution time in R

A slightly nicer way of measuring execution time, is to use the rbenchmark package. This package (easily) allows you to specify how many times to replicate your test and would the relative benchmark should be.

See also a related question at stats.stackexchange

Checking for directory and file write permissions in .NET

according to this link: http://www.authorcode.com/how-to-check-file-permission-to-write-in-c/

it's easier to use existing class SecurityManager

string FileLocation = @"C:\test.txt";
FileIOPermission writePermission = new FileIOPermission(FileIOPermissionAccess.Write, FileLocation);
if (SecurityManager.IsGranted(writePermission))
{
  // you have permission
}
else
{
 // permission is required!
}

but it seems it's been obsoleted, it is suggested to use PermissionSet instead.

[Obsolete("IsGranted is obsolete and will be removed in a future release of the .NET Framework.  Please use the PermissionSet property of either AppDomain or Assembly instead.")]

Setting PHP tmp dir - PHP upload not working

My problem was selinux...

Go sestatus

If Current mode: enforcing

Then chcon -R -t httpd_sys_rw_content_t /var/www/html

JS map return object

map rockets and add 10 to its launches:

_x000D_
_x000D_
var rockets = [_x000D_
    { country:'Russia', launches:32 },_x000D_
    { country:'US', launches:23 },_x000D_
    { country:'China', launches:16 },_x000D_
    { country:'Europe(ESA)', launches:7 },_x000D_
    { country:'India', launches:4 },_x000D_
    { country:'Japan', launches:3 }_x000D_
];_x000D_
rockets.map((itm) => {_x000D_
    itm.launches += 10_x000D_
    return itm_x000D_
})_x000D_
console.log(rockets)
_x000D_
_x000D_
_x000D_

If you don't want to modify rockets you can do:

var plusTen = []
rockets.forEach((itm) => {
    plusTen.push({'country': itm.country, 'launches': itm.launches + 10})
})

Convert integer value to matching Java Enum

static final PcapLinkType[] values  = { DLT_NULL, DLT_EN10MB, DLT_EN3MB, null ...}    

...

public static PcapLinkType  getPcapLinkTypeForInt(int num){    
    try{    
       return values[int];    
    }catch(ArrayIndexOutOfBoundsException e){    
       return DLT_UKNOWN;    
    }    
}    

Writing data to a local text file with javascript

Our HTML:

<div id="addnew">
    <input type="text" id="id">
    <input type="text" id="content">
    <input type="button" value="Add" id="submit">
</div>

<div id="check">
    <input type="text" id="input">
    <input type="button" value="Search" id="search">
</div>

JS (writing to the txt file):

function writeToFile(d1, d2){
    var fso = new ActiveXObject("Scripting.FileSystemObject");
    var fh = fso.OpenTextFile("data.txt", 8, false, 0);
    fh.WriteLine(d1 + ',' + d2);
    fh.Close();
}
var submit = document.getElementById("submit");
submit.onclick = function () {
    var id      = document.getElementById("id").value;
    var content = document.getElementById("content").value;
    writeToFile(id, content);
}

checking a particular row:

function readFile(){
    var fso = new ActiveXObject("Scripting.FileSystemObject");
    var fh = fso.OpenTextFile("data.txt", 1, false, 0);
    var lines = "";
    while (!fh.AtEndOfStream) {
        lines += fh.ReadLine() + "\r";
    }
    fh.Close();
    return lines;
}
var search = document.getElementById("search");
search.onclick = function () {
    var input   = document.getElementById("input").value;
    if (input != "") {
        var text    = readFile();
        var lines   = text.split("\r");
        lines.pop();
        var result;
        for (var i = 0; i < lines.length; i++) {
            if (lines[i].match(new RegExp(input))) {
                result = "Found: " + lines[i].split(",")[1];
            }
        }
        if (result) { alert(result); }
        else { alert(input + " not found!"); }
    }
}

Put these inside a .hta file and run it. Tested on W7, IE11. It's working. Also if you want me to explain what's going on, say so.

What is a predicate in c#?

The Predicate will always return a boolean, by definition.

Predicate<T> is basically identical to Func<T,bool>.

Predicates are very useful in programming. They are often used to allow you to provide logic at runtime, that can be as simple or as complicated as necessary.

For example, WPF uses a Predicate<T> as input for Filtering of a ListView's ICollectionView. This lets you write logic that can return a boolean determining whether a specific element should be included in the final view. The logic can be very simple (just return a boolean on the object) or very complex, all up to you.

ActionBarCompat: java.lang.IllegalStateException: You need to use a Theme.AppCompat

To simply add ActionBar Compat your activity or application should use @style/Theme.AppCompat theme in AndroidManifest.xml like this:

   <activity
        ...
        android:theme="@style/Theme.AppCompat" />

This will add actionbar in activty(or all activities if you added this theme to application)


But usually you need to customize you actionbar. To do this you need to create two styles with Theme.AppCompat parent, for example, "@style/Theme.AppCompat.Light". First one will be for api 11>= (versions of android with build in android actionbar), second one for api 7-10 (no build in actionbar).

Let's look at first style. It will be located in res/values-v11/styles.xml . It will look like this:

<style name="Theme.Styled" parent="@style/Theme.AppCompat.Light">
    <!-- Setting values in the android namespace affects API levels 11+ -->
    <item name="android:actionBarStyle">@style/Widget.Styled.ActionBar</item>
</style>

<style name="Widget.Styled.ActionBar" parent="@style/Widget.AppCompat.Light.ActionBar">
    <!-- Setting values in the android namespace affects API levels 11+ -->
    <item name="android:background">@drawable/ab_custom_solid_styled</item>
    <item name="android:backgroundStacked"
      >@drawable/ab_custom_stacked_solid_styled</item>
    <item name="android:backgroundSplit"
      >@drawable/ab_custom_bottom_solid_styled</item>
</style>

And you need to have same style for api 7-10. It will be located in res/values/styles.xml, BUT because that api levels don't yet know about original android actionbar style items, we should use one, provided by support library. ActionBar Compat items are defined just like original android, but without "android:" part in the front:

<style name="Theme.Styled" parent="@style/Theme.AppCompat.Light">
    <!-- Setting values in the default namespace affects API levels 7-11 -->
    <item name="actionBarStyle">@style/Widget.Styled.ActionBar</item>
</style>

<style name="Widget.Styled.ActionBar" parent="@style/Widget.AppCompat.Light.ActionBar">
    <!-- Setting values in the default namespace affects API levels 7-11 -->
    <item name="background">@drawable/ab_custom_solid_styled</item>
    <item name="backgroundStacked">@drawable/ab_custom_stacked_solid_styled</item>
    <item name="backgroundSplit">@drawable/ab_custom_bottom_solid_styled</item>
</style>

Please mark that, even if api levels higher than 10 already have actionbar you should still use AppCompat styles. If you don't, you will have this error on launch of Acitvity on devices with android 3.0 and higher:

java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.

Here is link this original article http://android-developers.blogspot.com/2013/08/actionbarcompat-and-io-2013-app-source.html written by Chris Banes.

P.S. Sorry for my English

jQuery addClass onClick

Try to make your css more specific so that the new (green) style is more specific than the previous one, so that it worked for me!

For example, you might use in css:

button:active {/*your style here*/}

Instead of (probably not working):

.active {/*style*/} (.active is not a pseudo-class)

Hope it helps!

How to skip the OPTIONS preflight request?

I think best way is check if request is of type "OPTIONS" return 200 from middle ware. It worked for me.

express.use('*',(req,res,next) =>{
      if (req.method == "OPTIONS") {
        res.status(200);
        res.send();
      }else{
        next();
      }
    });

How do you clear a stringstream variable?

For all the standard library types the member function empty() is a query, not a command, i.e. it means "are you empty?" not "please throw away your contents".

The clear() member function is inherited from ios and is used to clear the error state of the stream, e.g. if a file stream has the error state set to eofbit (end-of-file), then calling clear() will set the error state back to goodbit (no error).

For clearing the contents of a stringstream, using:

m.str("");

is correct, although using:

m.str(std::string());

is technically more efficient, because you avoid invoking the std::string constructor that takes const char*. But any compiler these days should be able to generate the same code in both cases - so I would just go with whatever is more readable.

How can I obfuscate (protect) JavaScript?

This one minifies but doesn't obfuscate. If you don't want to use command line Java you can paste your javascript into a webform.

Installing Java on OS X 10.9 (Mavericks)

The new Mavericks (10.9) showed me the "Requesting install", but nothing happened.

The solution was to manually download and install the official Java package for OS X, which is in Java for OS X 2013-005.

Update: As mentioned in the comments below, there is a newer version of this same package:

Java for OS X 2014-001

Java for OS X 2014-001 (Correcting dead line above)

Java for OS X 2014-001 includes installation improvements, and supersedes all previous versions of Java for OS X. This package installs the same version of Java 6 included in Java for OS X 2013-005.

Height of an HTML select box (dropdown)

NO. It's not possible to change height of a select dropdown because that property is browser specific.

However if you want that functionality, then there are many options. You can use bootstrap dropdown-menu and define it's max-height property. Something like this.

_x000D_
_x000D_
$('.dropdown-menu').on( 'click', 'a', function() {_x000D_
    var text = $(this).html();_x000D_
    var htmlText = text + ' <span class="caret"></span>';_x000D_
    $(this).closest('.dropdown').find('.dropdown-toggle').html(htmlText);_x000D_
});
_x000D_
.dropdown-menu {_x000D_
    max-height: 146px;_x000D_
    overflow: scroll;_x000D_
    overflow-x: hidden;_x000D_
    margin-top: 0px;_x000D_
}_x000D_
_x000D_
.caret {_x000D_
   float: right;_x000D_
    margin-top: 5%;_x000D_
}_x000D_
_x000D_
#menu1 {_x000D_
    width: 160px; _x000D_
    text-align: left;_x000D_
}
_x000D_
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">_x000D_
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>_x000D_
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>_x000D_
   _x000D_
<div class="container" style="margin:10px">_x000D_
  <div class="dropdown">_x000D_
    <button class="btn btn-default dropdown-toggle" type="button" id="menu1" data-toggle="dropdown">Tutorials_x000D_
    <span class="caret"></span></button>_x000D_
    <ul class="dropdown-menu" role="menu" aria-labelledby="menu1">_x000D_
      <li><a href="#">HTML</a></li>_x000D_
      <li><a href="#">CSS</a></li>_x000D_
      <li><a href="#">JavaScript</a></li>_x000D_
      <li><a href="#">About Us</a></li>_x000D_
      <li><a href="#">HTML</a></li>_x000D_
      <li><a href="#">CSS</a></li>_x000D_
      <li><a href="#">JavaScript</a></li>_x000D_
      <li><a href="#">About Us</a></li>_x000D_
      <li><a href="#">HTML</a></li>_x000D_
      <li><a href="#">CSS</a></li>_x000D_
      <li><a href="#">JavaScript</a></li>_x000D_
      <li><a href="#">About Us</a></li>_x000D_
      <li><a href="#">HTML</a></li>_x000D_
      <li><a href="#">CSS</a></li>_x000D_
      <li><a href="#">JavaScript</a></li>_x000D_
      <li><a href="#">About Us</a></li>_x000D_
      <li><a href="#">HTML</a></li>_x000D_
      <li><a href="#">CSS</a></li>_x000D_
      <li><a href="#">JavaScript</a></li>_x000D_
      <li><a href="#">About Us</a></li>_x000D_
      <li><a href="#">HTML</a></li>_x000D_
      <li><a href="#">CSS</a></li>_x000D_
      <li><a href="#">JavaScript</a></li>_x000D_
      <li><a href="#">About Us</a></li>_x000D_
    </ul>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Spring Boot without the web server

Remove folowing dependancy on your pom file will work for me

  <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

How can I use Async with ForEach?

This little extension method should give you exception-safe async iteration:

public static async Task ForEachAsync<T>(this List<T> list, Func<T, Task> func)
{
    foreach (var value in list)
    {
        await func(value);
    }
}

Since we're changing the return type of the lambda from void to Task, exceptions will propagate up correctly. This will allow you to write something like this in practice:

await db.Groups.ToList().ForEachAsync(async i => {
    await GetAdminsFromGroup(i.Gid);
});

Encoding an image file with base64

Borrowing from what Ivo van der Wijk and gnibbler have developed earlier, this is a dynamic solution

import cStringIO
import PIL.Image

image_data = None

def imagetopy(image, output_file):
    with open(image, 'rb') as fin:
        image_data = fin.read()

    with open(output_file, 'w') as fout:
        fout.write('image_data = '+ repr(image_data))

def pytoimage(pyfile):
    pymodule = __import__(pyfile)
    img = PIL.Image.open(cStringIO.StringIO(pymodule.image_data))
    img.show()

if __name__ == '__main__':
    imagetopy('spot.png', 'wishes.py')
    pytoimage('wishes')

You can then decide to compile the output image file with Cython to make it cool. With this method, you can bundle all your graphics into one module.

Homebrew refusing to link OpenSSL

The solution above from edwardthesecond worked for me too on Sierra

 brew install openssl
 cd /usr/local/include 
 ln -s ../opt/openssl/include/openssl 
 ./configure && make

Other steps I did before were:

  • installing openssl via brew

    brew install openssl
    
  • adding openssl to the path as suggested by homebrew

    brew info openssl
    echo 'export PATH="/usr/local/opt/openssl/bin:$PATH"' >> ~/.bash_profile
    

'if' statement in jinja2 template

Why the loop?

You could simply do this:

{% if 'priority' in data %}
    <p>Priority: {{ data['priority'] }}</p>
{% endif %}

When you were originally doing your string comparison, you should have used == instead.

Fastest way to convert a dict's keys & values from `unicode` to `str`?

def to_str(key, value):
    if isinstance(key, unicode):
        key = str(key)
    if isinstance(value, unicode):
        value = str(value)
    return key, value

pass key and value to it, and add recursion to your code to account for inner dictionary.

Inserting a blank table row with a smaller height

Just add the CSS rule (and the slightly improved mark-up) posted below and you should get the result that you're after.

CSS

.blank_row
{
    height: 10px !important; /* overwrites any other rules */
    background-color: #FFFFFF;
}

HTML

<tr class="blank_row">
    <td colspan="3"></td>
</tr>

Since I have no idea what your current stylesheet looks like I added the !important property just in case. If possible, though, you should remove it as one rarely wants to rely on !important declarations in a stylesheet considering the big possibility that they will mess it up later on.

Pip error: Microsoft Visual C++ 14.0 is required

Try doing this:

py -m pip install pipwin
py -m pipwin install PyAudio

How to create duplicate table with new name in SQL Server 2008

To create a new table from an existing table: (copying all rows from Old_Table into de New_Table):

SELECT * INTO New_table FROM  Old_Table

To copy the data from one table to another (when you have already created them):

Insert into Table_Name2 select top 1 * from Table_Name1

Remember to remove the top 1 argument and apply a relevant where clause if needed on the Select

Choosing a jQuery datagrid plugin?

You should look here: https://stackoverflow.com/questions/159025/jquery-grid-recommendations

Update

The link above takes to a question that was closed and then deleted. Here are the original suggestions that were on the most voted answer:

How to place the ~/.composer/vendor/bin directory in your PATH?

my path didn't have /.composer, just /composer so my path was:-

export PATH="$PATH:$HOME/.config/composer/vendor/bin"

This worked for me on ubuntu 20.04

Create ul and li elements in javascript.

Great then. Let's create a simple function that takes an array and prints our an ordered listview/list inside a div tag.

Step 1: Let's say you have an div with "contentSectionID" id.<div id="contentSectionID"></div>

Step 2: We then create our javascript function that returns a list component and takes in an array:

function createList(spacecrafts){

var listView=document.createElement('ol');

for(var i=0;i<spacecrafts.length;i++)
{
    var listViewItem=document.createElement('li');
    listViewItem.appendChild(document.createTextNode(spacecrafts[i]));
    listView.appendChild(listViewItem);
}

return listView;
}

Step 3: Finally we select our div and create a listview in it:

document.getElementById("contentSectionID").appendChild(createList(myArr));

What is the Swift equivalent of respondsToSelector?

I guess you want to make a default implementation for delegate. You can do this:

let defaultHandler = {}
(delegate?.method ?? defaultHandler)()

What exactly is the meaning of an API?

Lets say you are developing a game and you want the game user to login their facebook profile(to get your profile information) before playing it,so how your game is going to access facebook? Now here comes the API.Facebook has already written the program(API) for you to do it, you have to just use those programs in your game application.using Facebook-API you can use their services in your application.Here is a good and detailed look on API... http://money.howstuffworks.com/business-communications/how-to-leverage-an-api-for-conferencing1.htm

What Does 'zoom' do in CSS?

As Joshua M pointed out, the zoom function isn't supported only in Firefox, but you can simply fix this as shown:

div.zoom {
  zoom: 2; /* all browsers */
 -moz-transform: scale(2);  /* Firefox */
}

Changing the color of a clicked table row using jQuery

in your css:

.selected{
    background: #F00;
}

in the jquery:

$("#data tr").click(function(){
   $(this).toggleClass('selected');
});

Basically you create a class and adds/removes it from the selected row.

Btw you could have shown more effort, there's no css or jquery/js at all in your code xD

Nginx: stat() failed (13: permission denied)

You can also add which user will run the nginx. In the nginx.conf file, make the following changes:

user root;

You can add the above line as the first line in your nginx conf. You can write the name of any user who has the permission to write in that directory.

How to add a button programmatically in VBA next to some sheet cell data?

Suppose your function enters data in columns A and B and you want to a custom Userform to appear if the user selects a cell in column C. One way to do this is to use the SelectionChange event:

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    Dim clickRng As Range
    Dim lastRow As Long

    lastRow = Range("A1").End(xlDown).Row
    Set clickRng = Range("C1:C" & lastRow) //Dynamically set cells that can be clicked based on data in column A

    If Not Intersect(Target, clickRng) Is Nothing Then
        MyUserForm.Show //Launch custom userform
    End If

End Sub

Note that the userform will appear when a user selects any cell in Column C and you might want to populate each cell in Column C with something like "select cell to launch form" to make it obvious that the user needs to perform an action (having a button naturally suggests that it should be clicked)

How can I position my div at the bottom of its container?

Div of style, position:absolute;bottom:5px;width:100%; is working, But it required more scrollup situation.

window.onscroll = function() {
    var v = document.getElementById("copyright");
    v.style.position = "fixed";
    v.style.bottom = "5px";
}

How do you do dynamic / dependent drop downs in Google Sheets?

Here you have another solution based on the one provided by @tarheel

function onEdit() {
    var sheetWithNestedSelectsName = "Sitemap";
    var columnWithNestedSelectsRoot = 1;
    var sheetWithOptionPossibleValuesSuffix = "TabSections";

    var activeSpreadsheet = SpreadsheetApp.getActiveSpreadsheet();
    var activeSheet = SpreadsheetApp.getActiveSheet();

    // If we're not in the sheet with nested selects, exit!
    if ( activeSheet.getName() != sheetWithNestedSelectsName ) {
        return;
    }

    var activeCell = SpreadsheetApp.getActiveRange();

    // If we're not in the root column or a content row, exit!
    if ( activeCell.getColumn() != columnWithNestedSelectsRoot || activeCell.getRow() < 2 ) {
        return;
    }

    var sheetWithActiveOptionPossibleValues = activeSpreadsheet.getSheetByName( activeCell.getValue() + sheetWithOptionPossibleValuesSuffix );

    // Get all possible values
    var activeOptionPossibleValues = sheetWithActiveOptionPossibleValues.getSheetValues( 1, 1, -1, 1 );

    var possibleValuesValidation = SpreadsheetApp.newDataValidation();
    possibleValuesValidation.setAllowInvalid( false );
    possibleValuesValidation.requireValueInList( activeOptionPossibleValues, true );

    activeSheet.getRange( activeCell.getRow(), activeCell.getColumn() + 1 ).setDataValidation( possibleValuesValidation.build() );
}

It has some benefits over the other approach:

  • You don't need to edit the script every time you add a "root option". You only have to create a new sheet with the nested options of this root option.
  • I've refactored the script providing more semantic names for the variables and so on. Furthermore, I've extracted some parameters to variables in order to make it easier to adapt to your specific case. You only have to set the first 3 values.
  • There's no limit of nested option values (I've used the getSheetValues method with the -1 value).

So, how to use it:

  1. Create the sheet where you'll have the nested selectors
  2. Go to the "Tools" > "Script Editor…" and select the "Blank project" option
  3. Paste the code attached to this answer
  4. Modify the first 3 variables of the script setting up your values and save it
  5. Create one sheet within this same document for each possible value of the "root selector". They must be named as the value + the specified suffix.

Enjoy!

How to force a checkbox and text on the same line?

Try this CSS:

label {
  display: inline-block;
}

How to provide a mysql database connection in single file in nodejs

I took a similar approach as Sean3z but instead I have the connection closed everytime i make a query.

His way works if it's only executed on the entry point of your app, but let's say you have controllers that you want to do a var db = require('./db'). You can't because otherwise everytime you access that controller you will be creating a new connection.

To avoid that, i think it's safer, in my opinion, to open and close the connection everytime.

here is a snippet of my code.

mysq_query.js

// Dependencies
var mysql   = require('mysql'),
    config  = require("../config");

/*
 * @sqlConnection
 * Creates the connection, makes the query and close it to avoid concurrency conflicts.
 */
var sqlConnection = function sqlConnection(sql, values, next) {

    // It means that the values hasnt been passed
    if (arguments.length === 2) {
        next = values;
        values = null;
    }

    var connection = mysql.createConnection(config.db);
    connection.connect(function(err) {
        if (err !== null) {
            console.log("[MYSQL] Error connecting to mysql:" + err+'\n');
        }
    });

    connection.query(sql, values, function(err) {

        connection.end(); // close the connection

        if (err) {
            throw err;
        }

        // Execute the callback
        next.apply(this, arguments);
    });
}

module.exports = sqlConnection;

Than you can use it anywhere just doing like

var mysql_query = require('path/to/your/mysql_query');
mysql_query('SELECT * from your_table where ?', {id: '1'}, function(err, rows)   {
    console.log(rows);
});

UPDATED: config.json looks like

{
        "db": {
        "user"     : "USERNAME",
        "password" : "PASSWORD",
        "database" : "DATABASE_NAME",
        "socketPath": "/tmp/mysql.sock"
    }
}

Hope this helps.

How can I check if character in a string is a letter? (Python)

str.isalpha()

Return true if all characters in the string are alphabetic and there is at least one character, false otherwise. Alphabetic characters are those characters defined in the Unicode character database as “Letter”, i.e., those with general category property being one of “Lm”, “Lt”, “Lu”, “Ll”, or “Lo”. Note that this is different from the “Alphabetic” property defined in the Unicode Standard.

In python2.x:

>>> s = u'a1??'
>>> for char in s: print char, char.isalpha()
...
a True
1 False
? True
? True
>>> s = 'a1??'
>>> for char in s: print char, char.isalpha()
...
a True
1 False
? False
? False
? False
? False
? False
? False
>>>

In python3.x:

>>> s = 'a1??'
>>> for char in s: print(char, char.isalpha())
...
a True
1 False
? True
? True
>>>

This code work:

>>> def is_alpha(word):
...     try:
...         return word.encode('ascii').isalpha()
...     except:
...         return False
...
>>> is_alpha('??')
False
>>> is_alpha(u'??')
False
>>>

>>> a = 'a'
>>> b = 'a'
>>> ord(a), ord(b)
(65345, 97)
>>> a.isalpha(), b.isalpha()
(True, True)
>>> is_alpha(a), is_alpha(b)
(False, True)
>>>

gcloud command not found - while installing Google Cloud SDK

Now after running install.sh in Mac OS, google itself giving the information to run completion.bash.inc and path.bash.inc.

If you're using zsh terminal, it'll ask you to run completion.zsh.inc and path.zsh.inc. Please see the image below

enter image description here

Adding a default value in dropdownlist after binding with database

You can do it programmatically:

ddlColor.DataSource = from p in db.ProductTypes
                                  where p.ProductID == pID
                                  orderby p.Color 
                                  select new { p.Color };
ddlColor.DataTextField = "Color";
ddlColor.DataBind();
ddlColor.Items.Insert(0, new ListItem("Select", "NA"));

Or add it in markup as:

<asp:DropDownList .. AppendDataBoundItems="true">
   <Items>
       <asp:ListItem Text="Select" Value="" />
   </Items>
</asp:DropDownList>

How to print SQL statement in codeigniter model

You can use this:

$this->db->last_query();

"Returns the last query that was run (the query string, not the result)."

Reff: https://www.codeigniter.com/userguide3/database/helpers.html

Left Outer Join using + sign in Oracle 11g

Those two queries are performing OUTER JOIN. See below

Oracle recommends that you use the FROM clause OUTER JOIN syntax rather than the Oracle join operator. Outer join queries that use the Oracle join operator (+) are subject to the following rules and restrictions, which do not apply to the FROM clause OUTER JOIN syntax:

  • You cannot specify the (+) operator in a query block that also contains FROM clause join syntax.

  • The (+) operator can appear only in the WHERE clause or, in the context of left- correlation (when specifying the TABLE clause) in the FROM clause, and can be applied only to a column of a table or view.

  • If A and B are joined by multiple join conditions, then you must use the (+) operator in all of these conditions. If you do not, then Oracle Database will return only the rows resulting from a simple join, but without a warning or error to advise you that you do not have the results of an outer join.

  • The (+) operator does not produce an outer join if you specify one table in the outer query and the other table in an inner query.

  • You cannot use the (+) operator to outer-join a table to itself, although self joins are valid. For example, the following statement is not valid:

    -- The following statement is not valid:
    SELECT employee_id, manager_id
       FROM employees
       WHERE employees.manager_id(+) = employees.employee_id;
    

    However, the following self join is valid:

    SELECT e1.employee_id, e1.manager_id, e2.employee_id
       FROM employees e1, employees e2
       WHERE e1.manager_id(+) = e2.employee_id
       ORDER BY e1.employee_id, e1.manager_id, e2.employee_id;
    
  • The (+) operator can be applied only to a column, not to an arbitrary expression. However, an arbitrary expression can contain one or more columns marked with the (+) operator.

  • A WHERE condition containing the (+) operator cannot be combined with another condition using the OR logical operator.

  • A WHERE condition cannot use the IN comparison condition to compare a column marked with the (+) operator with an expression.

If the WHERE clause contains a condition that compares a column from table B with a constant, then the (+) operator must be applied to the column so that Oracle returns the rows from table A for which it has generated nulls for this column. Otherwise Oracle returns only the results of a simple join.

In a query that performs outer joins of more than two pairs of tables, a single table can be the null-generated table for only one other table. For this reason, you cannot apply the (+) operator to columns of B in the join condition for A and B and the join condition for B and C. Refer to SELECT for the syntax for an outer join.

Taken from http://download.oracle.com/docs/cd/B28359_01/server.111/b28286/queries006.htm

Using SHA1 and RSA with java.security.Signature vs. MessageDigest and Cipher

I have a similar problem, I tested adding code and found some interesting results. With this code I add, I can deduce that depending on the "provider" to use, the firm can be different? (because the data included in the encryption is not always equal in all providers).

Results of my test.

Conclusion.- Signature Decipher= ???(trash) + DigestInfo (if we know the value of "trash", the digital signatures will be equal)

IDE Eclipse OUTPUT...

Input data: This is the message being signed

Digest: 62b0a9ef15461c82766fb5bdaae9edbe4ac2e067

DigestInfo: 3021300906052b0e03021a0500041462b0a9ef15461c82766fb5bdaae9edbe4ac2e067

Signature Decipher: 1ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff003021300906052b0e03021a0500041462b0a9ef15461c82766fb5bdaae9edbe4ac2e067

CODE

import java.security.InvalidKeyException;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.SignatureException;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import org.bouncycastle.asn1.x509.DigestInfo;
import org.bouncycastle.asn1.DERObjectIdentifier;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
public class prueba {
/**
* @param args
* @throws NoSuchProviderException 
* @throws NoSuchAlgorithmException 
* @throws InvalidKeyException 
* @throws SignatureException 
* @throws NoSuchPaddingException 
* @throws BadPaddingException 
* @throws IllegalBlockSizeException 
*///
public static void main(String[] args) throws NoSuchAlgorithmException, NoSuchProviderException, InvalidKeyException, SignatureException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException {
// TODO Auto-generated method stub
KeyPair keyPair = KeyPairGenerator.getInstance("RSA","BC").generateKeyPair();
PrivateKey privateKey = keyPair.getPrivate();
PublicKey puKey = keyPair.getPublic();
String plaintext = "This is the message being signed";
// Hacer la firma
Signature instance = Signature.getInstance("SHA1withRSA","BC");
instance.initSign(privateKey);
instance.update((plaintext).getBytes());
byte[] signature = instance.sign();
// En dos partes primero hago un Hash
MessageDigest digest = MessageDigest.getInstance("SHA1", "BC");
byte[] hash = digest.digest((plaintext).getBytes());
// El digest es identico a  openssl dgst -sha1 texto.txt
//MessageDigest sha1 = MessageDigest.getInstance("SHA1","BC");
//byte[] digest = sha1.digest((plaintext).getBytes());
AlgorithmIdentifier digestAlgorithm = new AlgorithmIdentifier(new
DERObjectIdentifier("1.3.14.3.2.26"), null);
// create the digest info
DigestInfo di = new DigestInfo(digestAlgorithm, hash);
byte[] digestInfo = di.getDEREncoded();
//Luego cifro el hash
Cipher cipher = Cipher.getInstance("RSA","BC");
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
byte[] cipherText = cipher.doFinal(digestInfo);
//byte[] cipherText = cipher.doFinal(digest2);
Cipher cipher2 = Cipher.getInstance("RSA","BC");
cipher2.init(Cipher.DECRYPT_MODE, puKey);
byte[] cipherText2 = cipher2.doFinal(signature);
System.out.println("Input data: " + plaintext);
System.out.println("Digest: " + bytes2String(hash));
System.out.println("Signature: " + bytes2String(signature));
System.out.println("Signature2: " + bytes2String(cipherText));
System.out.println("DigestInfo: " + bytes2String(digestInfo));
System.out.println("Signature Decipher: " + bytes2String(cipherText2));
}

Loop through all the rows of a temp table and call a stored procedure for each row

you could use a cursor:

DECLARE @id int
DECLARE @pass varchar(100)

DECLARE cur CURSOR FOR SELECT Id, Password FROM @temp
OPEN cur

FETCH NEXT FROM cur INTO @id, @pass

WHILE @@FETCH_STATUS = 0 BEGIN
    EXEC mysp @id, @pass ... -- call your sp here
    FETCH NEXT FROM cur INTO @id, @pass
END

CLOSE cur    
DEALLOCATE cur

get dictionary value by key

I use a similar method to dasblinkenlight's in a function to return a single key value from a Cookie containing a JSON array loaded into a Dictionary as follows:

    /// <summary>
    /// Gets a single key Value from a Json filled cookie with 'cookiename','key' 
    /// </summary>
    public static string GetSpecialCookieKeyVal(string _CookieName, string _key)
    {
        //CALL COOKIE VALUES INTO DICTIONARY
        Dictionary<string, string> dictCookie =
        JsonConvert.DeserializeObject<Dictionary<string, string>>
         (MyCookinator.Get(_CookieName));

        string value;
        if (dictCookie.TryGetValue( _key, out value))
        {
            return value;
        }
        else
        {
            return "0";
        }

    }

Where "MyCookinator.Get()" is another simple Cookie function getting an http cookie overall value.

JQuery - how to select dropdown item based on value

In your case $("#mySelect").val("fg") :)

Changing width property of a :before css selector using JQuery

You may try to inherit property from the base class:

_x000D_
_x000D_
var width = 2;_x000D_
var interval = setInterval(function () {_x000D_
    var element = document.getElementById('box');_x000D_
    width += 0.0625;_x000D_
    element.style.width = width + 'em';_x000D_
    if (width >= 7) clearInterval(interval);_x000D_
}, 50);
_x000D_
.box {_x000D_
    /* Set property */_x000D_
    width:4em;_x000D_
    height:2em;_x000D_
    background-color:#d42;_x000D_
    position:relative;_x000D_
}_x000D_
.box:after {_x000D_
    /* Inherit property */_x000D_
    width:inherit;_x000D_
    content:"";_x000D_
    height:1em;_x000D_
    background-color:#2b4;_x000D_
    position:absolute;_x000D_
    top:100%;_x000D_
}
_x000D_
<div id="box" class="box"></div>
_x000D_
_x000D_
_x000D_

Escape sequence \f - form feed - what exactly is it?

From wiki page

12 (form feed, \f, ^L), to cause a printer to eject paper to the top of the next page, or a video terminal to clear the screen.

or more details here.

It seems that this symbol is rather obsolete now and the way it is processed may be(?) implementation dependent. At least for me your code gives the following output (xcode gcc 4.2, gdb console):

hello
    goodbye

How to send email from Terminal?

If you want to attach a file on Linux

echo 'mail content' | mailx -s 'email subject' -a attachment.txt [email protected]

Could not load file or assembly or one of its dependencies. Access is denied. The issue is random, but after it happens once, it continues

I ran into this problem and it turned out that a referenced package/assembly was being encrypted by Windows. This happened because my company implemented a policy to require the My Documents folder to be encrypted and my Visual Studio solutions happened to be under that directory.

I could manually go into the file/directory properties in Windows Explorer and disable encryption. But in my case this was a temporary solution since the network policy would eventually change it back. I wound up moving my VS solution to another un-encrypted location.

Simple VBA selection: Selecting 5 cells to the right of the active cell

This copies the 5 cells to the right of the activecell. If you have a range selected, the active cell is the top left cell in the range.

Sub Copy5CellsToRight()
    ActiveCell.Offset(, 1).Resize(1, 5).Copy
End Sub

If you want to include the activecell in the range that gets copied, you don't need the offset:

Sub ExtendAndCopy5CellsToRight()
    ActiveCell.Resize(1, 6).Copy
End Sub

Note that you don't need to select before copying.

How to use getJSON, sending data with post method?

Just add these lines to your <script> (somewhere after jQuery is loaded but before posting anything):

$.postJSON = function(url, data, func)
{
    $.post(url, data, func, 'json');
}

Replace (some/all) $.getJSON with $.postJSON and enjoy!

You can use the same Javascript callback functions as with $.getJSON. No server-side change is needed. (Well, I always recommend using $_REQUEST in PHP. http://php.net/manual/en/reserved.variables.request.php, Among $_REQUEST, $_GET and $_POST which one is the fastest?)

This is simpler than @lepe's solution.

How to convert "Mon Jun 18 00:00:00 IST 2012" to 18/06/2012?

You can also use a formula in excel in order to convert this type of date to a date type excel can read: =DATEVALUE(CONCATENATE(MID(A1,8,3),MID(A1,4,4),RIGHT(A1,4)))

And you get: 12/7/2016 from: Wed Dec 07 00:00:00 UTC 2016

Error in file(file, "rt") : cannot open the connection

Use setwd() to change to appropriate directory. Use only filename to access any file in the working directory. Navigate a folder above by using "../<filename>".

laravel 5.5 The page has expired due to inactivity. Please refresh and try again

my problem solved by just adding @csrf in form tag

Laravel 5.6 doesn't support {{ csrf_field() }} just add @csrf in place of {{ csrf_field() }}

larvel_fix_error.png

how to start the tomcat server in linux?

I know this is old question, but this command helped me!

Go to your Tomcat Directory
Just type this command in your terminal:

./catalina.sh start

GLYPHICONS - bootstrap icon font hex value

If you want to use glyph icons with bootstrap 2.3.2, Add the font files from bootstrap 3 to your project folder then copy this to your css file

 @font-face {
  font-family: 'Glyphicons Halflings';
  src: url('../fonts/glyphicons-halflings-regular.eot');
  src: url('../fonts/glyphicons-halflings-regular.eot?#iefix') format('embedded-opentype'), url('../fonts/glyphicons-halflings-regular.woff') format('woff'), url('../fonts/glyphicons-halflings-regular.ttf') format('truetype'), url('../fonts/glyphicons-halflings-regular.svg#glyphicons-halflingsregular') format('svg');
}

Setting Elastic search limit to "unlimited"

You can use the from and size parameters to page through all your data. This could be very slow depending on your data and how much is in the index.

http://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-from-size.html

jQuery Ajax requests are getting cancelled without being sent

For Dropzone.js case. In my case it's was caused because of timeout option value was too low by default. So increase it by your needs.

{
// other dropzone options
timeout: 60000 * 10, // 10 minutes
...
}

Begin, Rescue and Ensure in Ruby?

Yes, ensure ensures that the code is always evaluated. That's why it's called ensure. So, it is equivalent to Java's and C#'s finally.

The general flow of begin/rescue/else/ensure/end looks like this:

begin
  # something which might raise an exception
rescue SomeExceptionClass => some_variable
  # code that deals with some exception
rescue SomeOtherException => some_other_variable
  # code that deals with some other exception
else
  # code that runs only if *no* exception was raised
ensure
  # ensure that this code always runs, no matter what
  # does not change the final value of the block
end

You can leave out rescue, ensure or else. You can also leave out the variables in which case you won't be able to inspect the exception in your exception handling code. (Well, you can always use the global exception variable to access the last exception that was raised, but that's a little bit hacky.) And you can leave out the exception class, in which case all exceptions that inherit from StandardError will be caught. (Please note that this does not mean that all exceptions are caught, because there are exceptions which are instances of Exception but not StandardError. Mostly very severe exceptions that compromise the integrity of the program such as SystemStackError, NoMemoryError, SecurityError, NotImplementedError, LoadError, SyntaxError, ScriptError, Interrupt, SignalException or SystemExit.)

Some blocks form implicit exception blocks. For example, method definitions are implicitly also exception blocks, so instead of writing

def foo
  begin
    # ...
  rescue
    # ...
  end
end

you write just

def foo
  # ...
rescue
  # ...
end

or

def foo
  # ...
ensure
  # ...
end

The same applies to class definitions and module definitions.

However, in the specific case you are asking about, there is actually a much better idiom. In general, when you work with some resource which you need to clean up at the end, you do that by passing a block to a method which does all the cleanup for you. It's similar to a using block in C#, except that Ruby is actually powerful enough that you don't have to wait for the high priests of Microsoft to come down from the mountain and graciously change their compiler for you. In Ruby, you can just implement it yourself:

# This is what you want to do:
File.open('myFile.txt', 'w') do |file|
  file.puts content
end

# And this is how you might implement it:
def File.open(filename, mode='r', perm=nil, opt=nil)
  yield filehandle = new(filename, mode, perm, opt)
ensure
  filehandle&.close
end

And what do you know: this is already available in the core library as File.open. But it is a general pattern that you can use in your own code as well, for implementing any kind of resource cleanup (à la using in C#) or transactions or whatever else you might think of.

The only case where this doesn't work, if acquiring and releasing the resource are distributed over different parts of the program. But if it is localized, as in your example, then you can easily use these resource blocks.


BTW: in modern C#, using is actually superfluous, because you can implement Ruby-style resource blocks yourself:

class File
{
    static T open<T>(string filename, string mode, Func<File, T> block)
    {
        var handle = new File(filename, mode);
        try
        {
            return block(handle);
        }
        finally
        {
            handle.Dispose();
        }
    }
}

// Usage:

File.open("myFile.txt", "w", (file) =>
{
    file.WriteLine(contents);
});

What is the maximum number of characters that nvarchar(MAX) will hold?

2^31-1 bytes. So, a little less than 2^31-1 characters for varchar(max) and half that for nvarchar(max).

nchar and nvarchar

Google Chrome display JSON AJAX response as tree and not as a plain text

To see a tree view in recent versions of Chrome:

Navigate to Developer Tools > Network > the given response > Preview

Sorting dropdown alphabetically in AngularJS

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

module.controller("orderByController", function ($scope) {
    $scope.orderByValue = function (value) {
        return value;
    };

    $scope.items = ["c", "b", "a"];
    $scope.objList = [
        {
            "name": "c"
        }, {
            "name": "b"
        }, {
            "name": "a"
        }];
        $scope.item = "b";
    });

http://jsfiddle.net/Nfv42/65/

How to join multiple collections with $lookup in mongodb

You can actually chain multiple $lookup stages. Based on the names of the collections shared by profesor79, you can do this :

db.sivaUserInfo.aggregate([
    {
        $lookup: {
           from: "sivaUserRole",
           localField: "userId",
           foreignField: "userId",
           as: "userRole"
        }
    },
    {
        $unwind: "$userRole"
    },
    {
        $lookup: {
            from: "sivaUserInfo",
            localField: "userId",
            foreignField: "userId",
            as: "userInfo"
        }
    },
    {
        $unwind: "$userInfo"
    }
])

This will return the following structure :

{
    "_id" : ObjectId("56d82612b63f1c31cf906003"),
    "userId" : "AD",
    "phone" : "0000000000",
    "userRole" : {
        "_id" : ObjectId("56d82612b63f1c31cf906003"),
        "userId" : "AD",
        "role" : "admin"
    },
    "userInfo" : {
        "_id" : ObjectId("56d82612b63f1c31cf906003"),
        "userId" : "AD",
        "phone" : "0000000000"
    }
}

Maybe this could be considered an anti-pattern because MongoDB wasn't meant to be relational but it is useful.

Convert byte to string in Java

Use char instead of byte:

System.out.println("string " + (char)0x63);

Or if you want to be a Unicode puritan, you use codepoints:

System.out.println("string " + new String(new int[]{ 0x63 }, 0, 1));

And if you like the old skool US-ASCII "every byte is a character" idea:

System.out.println("string " + new String(new byte[]{ (byte)0x63 },
                                          StandardCharsets.US_ASCII));

Avoid using the String(byte[]) constructor recommended in other answers; it relies on the default charset. Circumstances could arise where 0x63 actually isn't the character c.

JComboBox Selection Change Listener?

You may try these

 int selectedIndex = myComboBox.getSelectedIndex();

-or-

Object selectedObject = myComboBox.getSelectedItem();

-or-

String selectedValue = myComboBox.getSelectedValue().toString();

org.hibernate.exception.SQLGrammarException: could not insert [com.sample.Person]

I solved the error by modifying the following property in hibernate.cfg.xml

  <property name="hibernate.hbm2ddl.auto">validate</property>

Earlier, the table was getting deleted each time I ran the program and now it doesnt, as hibernate only validates the schema and does not affect changes to it.

How can I specify a local gem in my Gemfile?

You can also reference a local gem with git if you happen to be working on it.

gem 'foo',
  :git => '/Path/to/local/git/repo',
  :branch => 'my-feature-branch'

Then, if it changes I run

bundle exec gem uninstall foo
bundle update foo

But I am not sure everyone needs to run these two steps.

Warning: mysql_connect(): Access denied for user 'root'@'localhost' (using password: YES)

try $conn = mysql_connect("localhost", "root") or $conn = mysql_connect("localhost", "root", "")

Releasing memory in Python

First, you may want to install glances:

sudo apt-get install python-pip build-essential python-dev lm-sensors 
sudo pip install psutil logutils bottle batinfo https://bitbucket.org/gleb_zhulik/py3sensors/get/tip.tar.gz zeroconf netifaces pymdstat influxdb elasticsearch potsdb statsd pystache docker-py pysnmp pika py-cpuinfo bernhard
sudo pip install glances

Then run it in the terminal!

glances

In your Python code, add at the begin of the file, the following:

import os
import gc # Garbage Collector

After using the "Big" variable (for example: myBigVar) for which, you would like to release memory, write in your python code the following:

del myBigVar
gc.collect()

In another terminal, run your python code and observe in the "glances" terminal, how the memory is managed in your system!

Good luck!

P.S. I assume you are working on a Debian or Ubuntu system

Best C++ Code Formatter/Beautifier

AStyle can be customized in great detail for C++ and Java (and others too)

This is a source code formatting tool.


clang-format is a powerful command line tool bundled with the clang compiler which handles even the most obscure language constructs in a coherent way.

It can be integrated with Visual Studio, Emacs, Vim (and others) and can format just the selected lines (or with git/svn to format some diff).

It can be configured with a variety of options listed here.

When using config files (named .clang-format) styles can be per directory - the closest such file in parent directories shall be used for a particular file.

Styles can be inherited from a preset (say LLVM or Google) and can later override different options

It is used by Google and others and is production ready.


Also look at the project UniversalIndentGUI. You can experiment with several indenters using it: AStyle, Uncrustify, GreatCode, ... and select the best for you. Any of them can be run later from a command line.


Uncrustify has a lot of configurable options. You'll probably need Universal Indent GUI (in Konstantin's reply) as well to configure it.

Implementing a simple file download servlet

That depends. If said file is publicly available via your HTTP server or servlet container you can simply redirect to via response.sendRedirect().

If it's not, you'll need to manually copy it to response output stream:

OutputStream out = response.getOutputStream();
FileInputStream in = new FileInputStream(my_file);
byte[] buffer = new byte[4096];
int length;
while ((length = in.read(buffer)) > 0){
    out.write(buffer, 0, length);
}
in.close();
out.flush();

You'll need to handle the appropriate exceptions, of course.

converting json to string in python

json.dumps() is much more than just making a string out of a Python object, it would always produce a valid JSON string (assuming everything inside the object is serializable) following the Type Conversion Table.

For instance, if one of the values is None, the str() would produce an invalid JSON which cannot be loaded:

>>> data = {'jsonKey': None}
>>> str(data)
"{'jsonKey': None}"
>>> json.loads(str(data))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 338, in loads
    return _default_decoder.decode(s)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 366, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 382, in raw_decode
    obj, end = self.scan_once(s, idx)
ValueError: Expecting property name: line 1 column 2 (char 1)

But the dumps() would convert None into null making a valid JSON string that can be loaded:

>>> import json
>>> data = {'jsonKey': None}
>>> json.dumps(data)
'{"jsonKey": null}'
>>> json.loads(json.dumps(data))
{u'jsonKey': None}

UTF-8 output from PowerShell

Spent some time working on a solution to my issue and thought it may be of interest. I ran into a problem trying to automate code generation using PowerShell 3.0 on Windows 8. The target IDE was the Keil compiler using MDK-ARM Essential Toolchain 5.24.1. A bit different from OP, as I am using PowerShell natively during the pre-build step. When I tried to #include the generated file, I received the error

fatal error: UTF-16 (LE) byte order mark detected '..\GITVersion.h' but encoding is not supported

I solved the problem by changing the line that generated the output file from:

out-file -FilePath GITVersion.h -InputObject $result

to:

out-file -FilePath GITVersion.h -Encoding ascii -InputObject $result

How to embed a YouTube channel into a webpage

In order to embed your channel, all you need to do is copy then paste the following code in another web-page.

<script src="http://www.gmodules.com/ig/ifr?url=http://www.google.com/ig/modules/youtube.xml&up_channel=YourChannelName&synd=open&w=320&h=390&title=&border=%23ffffff%7C3px%2C1px+solid+%23999999&output=js"></script>

Make sure to replace the YourChannelName with your actual channel name.

For example: if your channel name were CaliChick94066 your channel embed code would be:

<script src="http://www.gmodules.com/ig/ifr?url=http://www.google.com/ig/modules/youtube.xml&up_channel=CaliChick94066&synd=open&w=320&h=390&title=&border=%23ffffff%7C3px%2C1px+solid+%23999999&output=js"></script>

Please look at the following links:

YouTube on your site

Embed YouTube Channel

You just have to name the URL to your channel name. Also you can play with the height and the border color and size. Hope it helps

Difference between virtual and abstract methods

First of all you should know the difference between a virtual and abstract method.

Abstract Method

  • Abstract Method resides in abstract class and it has no body.
  • Abstract Method must be overridden in non-abstract child class.

Virtual Method

  • Virtual Method can reside in abstract and non-abstract class.
  • It is not necessary to override virtual method in derived but it can be.
  • Virtual method must have body ....can be overridden by "override keyword".....

ES6 class variable alternatives

Just to add to Benjamin's answer — class variables are possible, but you wouldn't use prototype to set them.

For a true class variable you'd want to do something like the following:

class MyClass {}
MyClass.foo = 'bar';

From within a class method that variable can be accessed as this.constructor.foo (or MyClass.foo).

These class properties would not usually be accessible from to the class instance. i.e. MyClass.foo gives 'bar' but new MyClass().foo is undefined

If you want to also have access to your class variable from an instance, you'll have to additionally define a getter:

class MyClass {
    get foo() {
        return this.constructor.foo;
    }
}

MyClass.foo = 'bar';

I've only tested this with Traceur, but I believe it will work the same in a standard implementation.

JavaScript doesn't really have classes. Even with ES6 we're looking at an object- or prototype-based language rather than a class-based language. In any function X () {}, X.prototype.constructor points back to X. When the new operator is used on X, a new object is created inheriting X.prototype. Any undefined properties in that new object (including constructor) are looked up from there. We can think of this as generating object and class properties.

XPath test if node value is number

There's an amazing type test operator in XPath 2.0 you can use:

<xsl:if test="$number castable as xs:double">
    <!-- implementation -->
</xsl:if>

Counting no of rows returned by a select query

The syntax error is just due to a missing alias for the subquery:

select COUNT(*) from
(
select m.Company_id
from Monitor as m
    inner join Monitor_Request as mr on mr.Company_ID=m.Company_id
    group by m.Company_id
    having COUNT(m.Monitor_id)>=5)  mySubQuery  /* Alias */

How to set a maximum execution time for a mysql query?

You can find the answer on this other S.O. question:

MySQL - can I limit the maximum time allowed for a query to run?

a cron job that runs every second on your database server, connecting and doing something like this:

  • SHOW PROCESSLIST
  • Find all connections with a query time larger than your maximum desired time
  • Run KILL [process id] for each of those processes

Check if an element is present in an array

Since ECMAScript6, one can use Set :

var myArray = ['A', 'B', 'C'];
var mySet = new Set(myArray);
var hasB = mySet.has('B'); // true
var hasZ = mySet.has('Z'); // false

How to get option text value using AngularJS?

Instead of ng-options="product as product.label for product in products"> in the select element, you can even use this:

<option ng-repeat="product in products" value="{{product.label}}">{{product.label}}

which works just fine as well.

REACT - toggle class onclick

A good sample would help to understand things better:

HTML

<div id="root">
</div>

CSS

.box {
  display: block;
  width: 200px;
  height: 200px;
  background-color: gray;
  color: white;
  text-align: center;
  vertical-align: middle;
  cursor: pointer;
}
.box.green {
  background-color: green; 
}

React code

class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {addClass: false}
  }
  toggle() {
    this.setState({addClass: !this.state.addClass});
  }
  render() {
    let boxClass = ["box"];
    if(this.state.addClass) {
      boxClass.push('green');
    }
    return(
        <div className={boxClass.join(' ')} onClick={this.toggle.bind(this)}>{this.state.addClass ? "Remove a class" : "Add a class (click the box)"}<br />Read the tutorial <a href="http://www.automationfuel.com" target="_blank">here</a>.</div>       
    );
  }
}
ReactDOM.render(<App />, document.getElementById("root"));

Multiple conditions in if statement shell script

if using /bin/sh you can use:

if [ <condition> ] && [ <condition> ]; then
    ...
fi

if using /bin/bash you can use:

if [[ <condition> && <condition> ]]; then
    ...
fi

What are the undocumented features and limitations of the Windows FINDSTR command?

Answer continued from part 1 above - I've run into the 30,000 character answer limit :-(

Limited Regular Expressions (regex) Support
FINDSTR support for regular expressions is extremely limited. If it is not in the HELP documentation, it is not supported.

Beyond that, the regex expressions that are supported are implemented in a completely non-standard manner, such that results can be different then would be expected coming from something like grep or perl.

Regex Line Position anchors ^ and $
^ matches beginning of input stream as well as any position immediately following a <LF>. Since FINDSTR also breaks lines after <LF>, a simple regex of "^" will always match all lines within a file, even a binary file.

$ matches any position immediately preceding a <CR>. This means that a regex search string containing $ will never match any lines within a Unix style text file, nor will it match the last line of a Windows text file if it is missing the EOL marker of <CR><LF>.

Note - As previously discussed, piped and redirected input to FINDSTR may have <CR><LF> appended that is not in the source. Obviously this can impact a regex search that uses $.

Any search string with characters before ^ or after $ will always fail to find a match.

Positional Options /B /E /X
The positional options work the same as ^ and $, except they also work for literal search strings.

/B functions the same as ^ at the start of a regex search string.

/E functions the same as $ at the end of a regex search string.

/X functions the same as having both ^ at the beginning and $ at the end of a regex search string.

Regex word boundary
\< must be the very first term in the regex. The regex will not match anything if any other characters precede it. \< corresponds to either the very beginning of the input, the beginning of a line (the position immediately following a <LF>), or the position immediately following any "non-word" character. The next character need not be a "word" character.

\> must be the very last term in the regex. The regex will not match anything if any other characters follow it. \> corresponds to either the end of input, the position immediately prior to a <CR>, or the position immediately preceding any "non-word" character. The preceding character need not be a "word" character.

Here is a complete list of "non-word" characters, represented as the decimal byte code. Note - this list was compiled on a U.S machine. I do not know what impact other languages may have on this list.

001   028   063   179   204   230
002   029   064   180   205   231
003   030   091   181   206   232
004   031   092   182   207   233
005   032   093   183   208   234
006   033   094   184   209   235
007   034   096   185   210   236
008   035   123   186   211   237
009   036   124   187   212   238
011   037   125   188   213   239
012   038   126   189   214   240
014   039   127   190   215   241
015   040   155   191   216   242
016   041   156   192   217   243
017   042   157   193   218   244
018   043   158   194   219   245
019   044   168   195   220   246
020   045   169   196   221   247
021   046   170   197   222   248
022   047   173   198   223   249
023   058   174   199   224   250
024   059   175   200   226   251
025   060   176   201   227   254
026   061   177   202   228   255
027   062   178   203   229

Regex character class ranges [x-y]
Character class ranges do not work as expected. See this question: Why does findstr not handle case properly (in some circumstances)?, along with this answer: https://stackoverflow.com/a/8767815/1012053.

The problem is FINDSTR does not collate the characters by their byte code value (commonly thought of as the ASCII code, but ASCII is only defined from 0x00 - 0x7F). Most regex implementations would treat [A-Z] as all upper case English capital letters. But FINDSTR uses a collation sequence that roughly corresponds to how SORT works. So [A-Z] includes the complete English alphabet, both upper and lower case (except for "a"), as well as non-English alpha characters with diacriticals.

Below is a complete list of all characters supported by FINDSTR, sorted in the collation sequence used by FINDSTR to establish regex character class ranges. The characters are represented as their decimal byte code value. I believe the collation sequence makes the most sense if the characters are viewed using code page 437. Note - this list was compiled on a U.S machine. I do not know what impact other languages may have on this list.

001
002
003
004
005
006
007
008
014
015
016
017
018           
019
020
021
022
023
024
025
026
027
028
029
030
031
127
039
045
032
255
009
010
011
012
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058
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064
091
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123
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173
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155
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043
249
060
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062
241
174
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246
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169
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196
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179
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176
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248
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048
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253
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236
097
065
166
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133
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142
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098
066
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135
128
100
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101
069
130
144
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161
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106
074
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252
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225
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Regex character class term limit and BUG
Not only is FINDSTR limited to a maximum of 15 character class terms within a regex, it fails to properly handle an attempt to exceed the limit. Using 16 or more character class terms results in an interactive Windows pop up stating "Find String (QGREP) Utility has encountered a problem and needs to close. We are sorry for the inconvenience." The message text varies slightly depending on the Windows version. Here is one example of a FINDSTR that will fail:

echo 01234567890123456|findstr [0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]

This bug was reported by DosTips user Judago here. It has been confirmed on XP, Vista, and Windows 7.

Regex searches fail (and may hang indefinitely) if they include byte code 0xFF (decimal 255)
Any regex search that includes byte code 0xFF (decimal 255) will fail. It fails if byte code 0xFF is included directly, or if it is implicitly included within a character class range. Remember that FINDSTR character class ranges do not collate characters based on the byte code value. Character <0xFF> appears relatively early in the collation sequence between the <space> and <tab> characters. So any character class range that includes both <space> and <tab> will fail.

The exact behavior changes slightly depending on the Windows version. Windows 7 hangs indefinitely if 0xFF is included. XP doesn't hang, but it always fails to find a match, and occasionally prints the following error message - "The process tried to write to a nonexistent pipe."

I no longer have access to a Vista machine, so I haven't been able to test on Vista.

Regex bug: . and [^anySet] can match End-Of-File
The regex . meta-character should only match any character other than <CR> or <LF>. There is a bug that allows it to match the End-Of-File if the last line in the file is not terminated by <CR> or <LF>. However, the . will not match an empty file.

For example, a file named "test.txt" containing a single line of x, without terminating <CR> or <LF>, will match the following:

findstr /r x......... test.txt

This bug has been confirmed on XP and Win7.

The same seems to be true for negative character sets. Something like [^abc] will match End-Of-File. Positive character sets like [abc] seem to work fine. I have only tested this on Win7.

How does the "final" keyword in Java work? (I can still modify an object.)

"A final variable can only be assigned once"

*Reflection* - "wowo wait, hold my beer".


Freeze of final fields happen in two scenarios:

  • End of constructor.
  • When reflection sets the field's value. (as many times as it wants to)

Let's break the law

public class HoldMyBeer 
{
    final int notSoFinal;
    
    public HoldMyBeer()
    {
       notSoFinal = 1;
    }

    static void holdIt(HoldMyBeer beer, int yetAnotherFinalValue) throws Exception
    {
       Class<HoldMyBeer> cl = HoldMyBeer.class;
       Field field = cl.getDeclaredField("notSoFinal");
       field.setAccessible(true);
       field.set(beer, yetAnotherFinalValue);
    }

    public static void main(String[] args) throws Exception 
    {
       HoldMyBeer beer = new HoldMyBeer();
       System.out.println(beer.notSoFinal);
       holdIt(beer, 50);
       System.out.println(beer.notSoFinal);
       holdIt(beer, 100);
       System.out.println(beer.notSoFinal);
       holdIt(beer, 666);
       System.out.println(beer.notSoFinal);
       holdIt(beer, 8888);
       System.out.println(beer.notSoFinal);
    }    
}

Output:

1
50
100
666
8888

The "final" field has been assigned 5 different "final" values (note the quotes). And it could keep being assigned different values over and over...

Why? Because reflection is like Chuck Norris, and if it wants to change the value of an initialized final field, it does. Some say he himself is the one that pushes the new values into the stack :

Code:
   7: astore_1
  11: aload_1
  12: getfield                
  18: aload_1
  19: bipush        50        //wait what
  27: aload_1
  28: getfield                
  34: aload_1
  35: bipush        100       //come on...
  43: aload_1
  44: getfield                
  50: aload_1
  51: sipush        666      //...you were supposed to be final...
  60: aload_1
  61: getfield                
  67: aload_1
  68: sipush        8888     //ok i'm out whatever dude
  77: aload_1
  78: getfield                

NSURLConnection Using iOS Swift

An abbreviated version of your code worked for me,

class Remote: NSObject {

    var data = NSMutableData()

    func connect(query:NSString) {
        var url =  NSURL.URLWithString("http://www.google.com")
        var request = NSURLRequest(URL: url)
        var conn = NSURLConnection(request: request, delegate: self, startImmediately: true)
    }


     func connection(didReceiveResponse: NSURLConnection!, didReceiveResponse response: NSURLResponse!) {
        println("didReceiveResponse")
    }

    func connection(connection: NSURLConnection!, didReceiveData conData: NSData!) {
        self.data.appendData(conData)
    }

    func connectionDidFinishLoading(connection: NSURLConnection!) {
        println(self.data)
    }


    deinit {
        println("deiniting")
    }
}

This is the code I used in the calling class,

class ViewController: UIViewController {

    var remote = Remote()


    @IBAction func downloadTest(sender : UIButton) {
        remote.connect("/apis")
    }

}

You didn't specify in your question where you had this code,

var remote = Remote()
remote.connect("/apis")

If var is a local variable, then the Remote class will be deallocated right after the connect(query:NSString) method finishes, but before the data returns. As you can see by my code, I usually implement reinit (or dealloc up to now) just to make sure when my instances go away. You should add that to your Remote class to see if that's your problem.

Linux error while loading shared libraries: cannot open shared object file: No such file or directory

Update
While what I write below is true as a general answer about shared libraries, I think the most frequent cause of these sorts of message is because you've installed a package, but not installed the "-dev" version of that package.


Well, it's not lying - there is no libpthread_rt.so.1 in that listing. You probably need to re-configure and re-build it so that it depends on the library you have, or install whatever provides libpthread_rt.so.1.

Generally, the numbers after the .so are version numbers, and you'll often find that they are symlinks to each other, so if you have version 1.1 of libfoo.so, you'll have a real file libfoo.so.1.0, and symlinks foo.so and foo.so.1 pointing to the libfoo.so.1.0. And if you install version 1.1 without removing the other one, you'll have a libfoo.so.1.1, and libfoo.so.1 and libfoo.so will now point to the new one, but any code that requires that exact version can use the libfoo.so.1.0 file. Code that just relies on the version 1 API, but doesn't care if it's 1.0 or 1.1 will specify libfoo.so.1. As orip pointed out in the comments, this is explained well at http://tldp.org/HOWTO/Program-Library-HOWTO/shared-libraries.html.

In your case, you might get away with symlinking libpthread_rt.so.1 to libpthread_rt.so. No guarantees that it won't break your code and eat your TV dinners, though.