Programs & Examples On #Wampserver

Specific release of the WAMP stack for Windows.

Project Links do not work on Wamp Server

$suppress_localhost = false;

This did the trick for me.

Could not execute menu item (internal error)[Exception] - When changing PHP version from 5.3.1 to 5.2.9

Some applications like skype uses wamp's default port:80 so you have to find out which application is accessing this port you can easily find it by using TCP View. End the service accessing this port and restart wamp server. Now it will work.

Composer Warning: openssl extension is missing. How to enable in WAMP

All those answers are good, but in fact, if you want to understand, the extension directory need to be right if you want all you uncommented extensions to work. Can write a physical or relative path like

extension_dir = "C:/myStack/php/ext"

or

extension_dir = "../../php/ext"

It's relative to the httpd.exe Apache web server (C:\myStack\apache\bin) But if you want it to work with Composer or anything you need the physical path because the cli mode doesn't use the web server !

How to enable local network users to access my WAMP sites?

it's simple , and it's really worked for me .

run you wamp server => click right mouse button => and click on "put online"

then open your cmd as an administrateur , and pass in this commande word

ipconfig => and press enter

then lot of adresses show-up , then you have just to take the first one , it's look like this example: Adresse IPv4. . . . . . . . . . . . . .: 192.168.67.190 well done ! , that's the adresse, that you will use to cennecte to your wampserver in local.

Forbidden: You don't have permission to access / on this server, WAMP Error

By default wamp sets the following as the default for any directory not explicitly declared:

<Directory />
    AllowOverride none
    Require all denied
</Directory>

For me, if I comment out the line that says Require all denied I started having access to the directory in question. I don't recommend this.

Instead in the directory directive I included Require local as below:

<Directory "C:/GitHub/head_count/">
    AllowOverride All
    Allow from all
    Require local
</Directory>

NOTE: I was still getting permission denied when I only had Allow from all. Adding Require local helped for me.

Wampserver icon not going green fully, mysql services not starting up?

For me, adding innodb_force_recovery=3 to my.ini solved the issue

Another option is removing ibdata files and all ib_logfile from the data directory , as explained in MySQL docs here. However this will cause any innoDB tables not to work(because the some information stored in ibdata1)

How to send an email using PHP?

The native PHP function mail() does not work for me. It issues the message:

503 This mail server requires authentication when attempting to send to a non-local e-mail address

So, I usually use PHPMailer package

I've downloaded the version 5.2.23 from: GitHub.

I've just picked 2 files and put them in my source PHP root

class.phpmailer.php
class.smtp.php

In PHP, the file needs to be added

require_once('class.smtp.php');
require_once('class.phpmailer.php');

After this, it's just code:

require_once('class.smtp.php');
require_once('class.phpmailer.php');
... 
//----------------------------------------------
// Send an e-mail. Returns true if successful 
//
//   $to - destination
//   $nameto - destination name
//   $subject - e-mail subject
//   $message - HTML e-mail body
//   altmess - text alternative for HTML.
//----------------------------------------------
function sendmail($to,$nameto,$subject,$message,$altmess)  {

  $from  = "[email protected]";
  $namefrom = "yourname";
  $mail = new PHPMailer();  
  $mail->CharSet = 'UTF-8';
  $mail->isSMTP();   // by SMTP
  $mail->SMTPAuth   = true;   // user and password
  $mail->Host       = "localhost";
  $mail->Port       = 25;
  $mail->Username   = $from;  
  $mail->Password   = "yourpassword";
  $mail->SMTPSecure = "";    // options: 'ssl', 'tls' , ''  
  $mail->setFrom($from,$namefrom);   // From (origin)
  $mail->addCC($from,$namefrom);      // There is also addBCC
  $mail->Subject  = $subject;
  $mail->AltBody  = $altmess;
  $mail->Body = $message;
  $mail->isHTML();   // Set HTML type
//$mail->addAttachment("attachment");  
  $mail->addAddress($to, $nameto);
  return $mail->send();
}

It works like a charm

WAMP 403 Forbidden message on Windows 7

hi there are 2 solutions :

  1. change the port 80 to 81 in the text file (httpd.conf) and click 127.0.0.1:81

  2. change setting the network go to control panel--network and internet--network and sharing center

click-->local area connection select-->propertis check true in the -allow other ..... and --- allo other .....

Import SQL file by command line in Windows 7

Related to importing, if you are having issues importing a file with bulk inserts and you're getting MYSQL GONE AWAY, lost connection or similar error, open your my.cnf / my.ini and temporarily set your max_allowed_packet to something large like 400M

Remember to set it back again after your import!

Wamp Server not goes to green color

I've had the above solutions work for me on many occasions, except one; that was after I buggered up an alias file - ie a file that allows the website folder to be located in another location other than the www folder. Here's the solution:

  1. Go to c:/wamp/alias
  2. Cut all of the alias files and paste in a temp folder somewhere
  3. Restart all WAMP services
  4. If the WAMP icon goes green, then add each alias file back to the alias folder one by one, restart WAMP, and when WAMP doesn't start, you know that alias file has some bad data in it. So, fix that file or delete it. Your choice.

WAMP Cannot access on local network 403 Forbidden

For Apache 2.4.9

in addition, look at the httpd-vhosts.conf file in C:\wamp\bin\apache\apache2.4.9\conf\extra

<VirtualHost *:80>
ServerName localhost
ServerAlias localhost
DocumentRoot C:/wamp/www
<Directory "C:/wamp/www/">
Options Indexes FollowSymLinks MultiViews
AllowOverride all
Require local
</Directory>
</VirtualHost>

Change to:

<VirtualHost *:80>
ServerName localhost
ServerAlias localhost
DocumentRoot C:/wamp/www
<Directory "C:/wamp/www/">
Options Indexes FollowSymLinks MultiViews
AllowOverride all
Require all granted
</Directory>
</VirtualHost>

changing from "Require local" to "Require all granted" solved the error 403 in my local network

wampserver doesn't go green - stays orange

you can run appache:

E:\wamp\bin\apache\apache2.4.9\bin\httpd.exe -d E:/wamp/bin/apache/apache2.4.9

after that see the log of error and solve it.

How to upgrade safely php version in wamp server

WAMP server generally provide addond for different php/mysql versions. However you mentioned you have downloaded latest wamp server. As of now, latest Wamp server v2.5 provide PHP version 5.5.12

So you need to upgrade it manually as follow:

  1. Download binaries on php.net
  2. Extract all files in a new folder : C:/wamp/bin/php/php5.5.27/
  3. Copy the wampserver.conf from another php folder (like php/php5.5.12/) to the new folder
  4. Rename php.ini-development file to phpForApache.ini
  5. Done ! Restart WampServer (>Right Mouseclick on trayicon >Exit)

Although not asked, I'd recommend to vagrant/puppet or docker for local development. Check puphpet.com for details. It has slight learning curve but it will give you much better control of different versions of every tool.

How can I access localhost from another computer in the same network?

localhost is a special hostname that almost always resolves to 127.0.0.1. If you ask someone else to connect to http://localhost they'll be connecting to their computer instead or yours.

To share your web server with someone else you'll need to find your IP address or your hostname and provide that to them instead. On windows you can find this with ipconfig /all on a command line.

You'll also need to make sure any firewalls you may have configured allow traffic on port 80 to connect to the WAMP server.

How to change the URL from "localhost" to something else, on a local system using wampserver?

Copy the hosts file and add 127.0.0.1 and name which you want to show or run at the browser link. For example:

127.0.0.1   abc

Then run abc/ as a local host in the browser.

1

Apache won't start in wamp

This solved the issue for me:

Right click on the WAMP system try icon -> Tools -> Reinstall all services

Can't use WAMP , port 80 is used by IIS 7.5

I just installed WAMP 3 on Windows 10 and did not have Apache in the WampServer system tray options.

But the httpd.conf file is located here:

C:\wamp64\bin\apache\apache2.4.17\conf\

In that folder, open httpd.conf with a text editor. Then go to line 62-63 and change 80 to 8080 like this:

Listen 0.0.0.0:8080
Listen [::0]:8080

Then go to the WampServer icon in the system tray and right-click > Exit, then Open WampServer again, and it should now turn green.

Now go to localhost:8080 to see your server config page.

Putting a password to a user in PhpMyAdmin in Wamp

i have some problems with it, and fixed it my using another config variable

$cfg['Servers'][$i]['AllowNoPassword'] = true;
instead
$cfg['Servers'][$i]['AllowNoPasswordRoot'] = true;

may be it will helpfull ot someone

How to use .htaccess in WAMP Server?

click: WAMP icon->Apache->Apache modules->chose rewrite_module

and do restart for all services.

Access denied for user 'root'@'localhost' with PHPMyAdmin

Edit your phpmyadmin config.inc.php file and if you have Password, insert that in front of Password in following code:

$cfg['Servers'][$i]['verbose'] = 'localhost';
$cfg['Servers'][$i]['host'] = 'localhost';
$cfg['Servers'][$i]['port'] = '3306';
$cfg['Servers'][$i]['socket'] = '';
$cfg['Servers'][$i]['connect_type'] = 'tcp';
$cfg['Servers'][$i]['extension'] = 'mysqli';
$cfg['Servers'][$i]['auth_type'] = 'config';
$cfg['Servers'][$i]['user'] = '**your-root-username**';
$cfg['Servers'][$i]['password'] = '**root-password**';
$cfg['Servers'][$i]['AllowNoPassword'] = true;

WAMP shows error 'MSVCR100.dll' is missing when install

I have tried all the above answers but still the same error was throwing up. Later I found this in WAMP Forum and finally my WAMP works !!!

If you are using WampServer 2.5 on a 64bit Windows You will need both the 32bit and 64bit versions of this runtime.

Microsoft Visual C++ 2012 (www.microsoft.com)

Press the Download button and on the following screen select VSU_4\vcredist_x86.exe Press the Download button and on the following screen select VSU_4\vcredist_x64.exe

Source : http://forum.wampserver.com/read.php?2,123608

Can't import database through phpmyadmin file size too large

For Upload large size data in using phpmyadmin Do following steps.

  1. Open php.ini file from C:\wamp\bin\apache\Apache2.4.4\bin Update following lines
    max_execution_time = 259200
    max_input_time = 259200
    memory_limit = 1000M
    upload_max_filesize = 750M
    post_max_size = 750M
    than after restart wamp server or restart all services Now Upload data using import function in phymyadmin. Apply second step if till not upload data.
  2. open config.default.php file in c:\wamp\apps\phpmyadmin4.0.4\libraries (Open this file accoring to phpmyadmin version)
    Find $cfg['ExecTimeLimit'] = 300;Replace to $cfg['ExecTimeLimit'] = 0;
    Now you can upload data.

You can also upload large size database using MySQL Console as below.

  1. Click on WampServer Icon -> MySQL -> MySQL Consol
  2. Enter your database password like root in popup
  3. Select database name for insert data by writing command USE DATABASENAME
  4. Then load source sql file as SOURCE C:\FOLDER\database.sql
  5. Press enter for insert data.

Note: You can't load a compressed database file e.g. database.sql.zip or database.sql.gz, you have to extract it first. Otherwise the console will just crash.

WampServer orange icon

I ran into this same problem this morning but none of the answers above provided me with the solution.

I realised eventually that my issue was because I had changed the DocumentRoot to a subfolder of the www directory, as I had previously been running a Symfony2 project inside www.

With the new project I am working on inside www, that old DocumentRoot dir did not exist any more so Apache failed to start.

wampserver -> Apache -> httpd.conf, then look for "DocumentRoot" and make sure the directory it points to exists or else change it to one that does.

Thank you to RiggsFolly, it was because of your hint about the Event Viewer above that I found the issue.

Scale Image to fill ImageView width and keep aspect ratio

To create an image with width equals screen width, and height proportionally set according to aspect ratio, do the following.

Glide.with(context).load(url).asBitmap().into(new SimpleTarget<Bitmap>() {
                    @Override
                    public void onResourceReady(Bitmap resource, GlideAnimation<? super Bitmap> glideAnimation) {

                        // creating the image that maintain aspect ratio with width of image is set to screenwidth.
                        int width = imageView.getMeasuredWidth();
                        int diw = resource.getWidth();
                        if (diw > 0) {
                            int height = 0;
                            height = width * resource.getHeight() / diw;
                            resource = Bitmap.createScaledBitmap(resource, width, height, false);
                        }
                                              imageView.setImageBitmap(resource);
                    }
                });

Hope this helps.

Get all rows from SQLite

Using Android's built in method

If you want every column and every row, then just pass in null for the SQLiteDatabase column and selection parameters.

Cursor cursor = db.query(TABLE_NAME, null, null, null, null, null, null, null);

More details

The other answers use rawQuery, but you can use Android's built in SQLiteDatabase. The documentation for query says that you can just pass in null to the selection parameter to get all the rows.

selection Passing null will return all rows for the given table.

And while you can also pass in null for the column parameter to get all of the columns (as in the one-liner above), it is better to only return the columns that you need. The documentation says

columns Passing null will return all columns, which is discouraged to prevent reading data from storage that isn't going to be used.

Example

SQLiteDatabase db = mHelper.getReadableDatabase();
String[] columns = {
        MyDatabaseHelper.COLUMN_1,
        MyDatabaseHelper.COLUMN_2,
        MyDatabaseHelper.COLUMN_3};
String selection = null; // this will select all rows
Cursor cursor = db.query(MyDatabaseHelper.MY_TABLE, columns, selection,
        null, null, null, null, null);

android splash screen sizes for ldpi,mdpi, hdpi, xhdpi displays ? - eg : 1024X768 pixels for ldpi

There can be any number of different screen sizes due to Android having no set standard size so as a guide you can use the minimum screen sizes, which are provided by Google.

According to Google's statistics the majority of ldpi displays are small screens and the majority of mdpi, hdpi, xhdpi and xxhdpi displays are normal sized screens.

  • xlarge screens are at least 960dp x 720dp
  • large screens are at least 640dp x 480dp
  • normal screens are at least 470dp x 320dp
  • small screens are at least 426dp x 320dp

You can view the statistics on the relative sizes of devices on Google's dashboard which is available here.

More information on multiple screens can be found here.

9 Patch image

The best solution is to create a nine-patch image so that the image's border can stretch to fit the size of the screen without affecting the static area of the image.

http://developer.android.com/guide/topics/graphics/2d-graphics.html#nine-patch

Better way to remove specific characters from a Perl string

With a character class this big it is easier to say what you want to keep. A caret in the first position of a character class inverts its sense, so you can write

$varTemp =~ s/[^"%'+\-0-9<=>a-z_{|}]+//gi

or, using the more efficient tr

$varTemp =~ tr/"%'+\-0-9<=>A-Z_a-z{|}//cd

tr docs

How to convert DATE to UNIX TIMESTAMP in shell script on MacOS

I used the following on Mac OSX.

currDate=`date +%Y%m%d`
epochDate=$(date -j -f "%Y%m%d" "${currDate}" "+%s")

Regex for quoted string with escaping quotes

This one comes from nanorc.sample available in many linux distros. It is used for syntax highlighting of C style strings

\"(\\.|[^\"])*\"

'ssh-keygen' is not recognized as an internal or external command

for those who does not choose BASH HERE option. type sh in cmd then they should have ssh-keygen.exe accessible

Is it possible to create a File object from InputStream

You need to create new file and copy contents from InputStream to that file:

File file = //...
try(OutputStream outputStream = new FileOutputStream(file)){
    IOUtils.copy(inputStream, outputStream);
} catch (FileNotFoundException e) {
    // handle exception here
} catch (IOException e) {
    // handle exception here
}

I am using convenient IOUtils.copy() to avoid manual copying of streams. Also it has built-in buffering.

Sorting Python list based on the length of the string

The same as in Eli's answer - just using a shorter form, because you can skip a lambda part here.

Creating new list:

>>> xs = ['dddd','a','bb','ccc']
>>> sorted(xs, key=len)
['a', 'bb', 'ccc', 'dddd']

In-place sorting:

>>> xs.sort(key=len)
>>> xs
['a', 'bb', 'ccc', 'dddd']

What is difference between sjlj vs dwarf vs seh?

SJLJ (setjmp/longjmp): – available for 32 bit and 64 bit – not “zero-cost”: even if an exception isn’t thrown, it incurs a minor performance penalty (~15% in exception heavy code) – allows exceptions to traverse through e.g. windows callbacks

DWARF (DW2, dwarf-2) – available for 32 bit only – no permanent runtime overhead – needs whole call stack to be dwarf-enabled, which means exceptions cannot be thrown over e.g. Windows system DLLs.

SEH (zero overhead exception) – will be available for 64-bit GCC 4.8.

source: https://wiki.qt.io/MinGW-64-bit

Vim for Windows - What do I type to save and exit from a file?

Instead of telling you how you could execute a certain command (Esc:wq), I can provide you two links that may help you with VIM:

However, the best way to learn Vim is not only using it for Git commits, but as a regular editor for your everyday work.

If you're not going to switch to Vim, it's nonsense to keep its commands in mind. In that case, go and set up your favourite editor to use with Git.

Sum across multiple columns with dplyr

I encounter this problem often, and the easiest way to do this is to use the apply() function within a mutate command.

library(tidyverse)
df=data.frame(
  x1=c(1,0,0,NA,0,1,1,NA,0,1),
  x2=c(1,1,NA,1,1,0,NA,NA,0,1),
  x3=c(0,1,0,1,1,0,NA,NA,0,1),
  x4=c(1,0,NA,1,0,0,NA,0,0,1),
  x5=c(1,1,NA,1,1,1,NA,1,0,1))

df %>%
  mutate(sum = select(., x1:x5) %>% apply(1, sum, na.rm=TRUE))

Here you could use whatever you want to select the columns using the standard dplyr tricks (e.g. starts_with() or contains()). By doing all the work within a single mutate command, this action can occur anywhere within a dplyr stream of processing steps. Finally, by using the apply() function, you have the flexibility to use whatever summary you need, including your own purpose built summarization function.

Alternatively, if the idea of using a non-tidyverse function is unappealing, then you could gather up the columns, summarize them and finally join the result back to the original data frame.

df <- df %>% mutate( id = 1:n() )   # Need some ID column for this to work

df <- df %>%
  group_by(id) %>%
  gather('Key', 'value', starts_with('x')) %>%
  summarise( Key.Sum = sum(value) ) %>%
  left_join( df, . )

Here I used the starts_with() function to select the columns and calculated the sum and you can do whatever you want with NA values. The downside to this approach is that while it is pretty flexible, it doesn't really fit into a dplyr stream of data cleaning steps.

Find first element in a sequence that matches a predicate

J.F. Sebastian's answer is most elegant but requires python 2.6 as fortran pointed out.

For Python version < 2.6, here's the best I can come up with:

from itertools import repeat,ifilter,chain
chain(ifilter(predicate,seq),repeat(None)).next()

Alternatively if you needed a list later (list handles the StopIteration), or you needed more than just the first but still not all, you can do it with islice:

from itertools import islice,ifilter
list(islice(ifilter(predicate,seq),1))

UPDATE: Although I am personally using a predefined function called first() that catches a StopIteration and returns None, Here's a possible improvement over the above example: avoid using filter / ifilter:

from itertools import islice,chain
chain((x for x in seq if predicate(x)),repeat(None)).next()

How can multiple rows be concatenated into one in Oracle without creating a stored procedure?

Easy:

SELECT question_id, wm_concat(element_id) as elements
FROM   questions
GROUP BY question_id;

Pesonally tested on 10g ;-)

From http://www.oracle-base.com/articles/10g/StringAggregationTechniques.php

size of NumPy array

This is called the "shape" in NumPy, and can be requested via the .shape attribute:

>>> a = zeros((2, 5))
>>> a.shape
(2, 5)

If you prefer a function, you could also use numpy.shape(a).

Set initially selected item in Select list in Angular2

The easiest way to solve this problem in Angular is to do:

In Template:

<select [ngModel]="selectedObjectIndex">
  <option [value]="i" *ngFor="let object of objects; let i = index;">{{object.name}}</option>
</select>

In your class:

this.selectedObjectIndex = 1/0/your number wich item should be selected

matplotlib.pyplot will not forget previous plots - how can I flush/refresh?

I would rather use plt.clf() after every plt.show() to just clear the current figure instead of closing and reopening it, keeping the window size and giving you a better performance and much better memory usage.

Similarly, you could do plt.cla() to just clear the current axes.

To clear a specific axes, useful when you have multiple axes within one figure, you could do for example:

fig, axes = plt.subplots(nrows=2, ncols=2)

axes[0, 1].clear()

Assign keyboard shortcut to run procedure

According to Microsoft's documentation

  1. On the Tools menu, point to Macro, and then click Macros.

  2. In the Macro name box, enter the name of the macro you want to assign to a keyboard shortcut key.

  3. Click Options.

  4. If you want to run the macro by pressing a keyboard shortcut key, enter a letter in the Shortcut key box. You can use CTRL+ letter (for lowercase letters) or CTRL+SHIFT+ letter (for uppercase letters), where letter is any letter key on the keyboard. The shortcut key cannot use a number or special character, such as @ or #.

    Note: The shortcut key will override any equivalent default Microsoft Excel shortcut keys while the workbook that contains the macro is open.

  5. If you want to include a description of the macro, type it in the Description box.

  6. Click OK.

  7. Click Cancel.

Avoid line break between html elements

CSS for that td: white-space: nowrap; should solve it.

Select all from table with Laravel and Eloquent

 public function getAllPosts()
 {
   return  Blog::all();        
 }

Have a look at the docs this is probably the first thing they explain..

1 = false and 0 = true?

I suspect it's just following the Linux / Unix standard for returning 0 on success.

Does it really say "1" is false and "0" is true?

jQuery window scroll event does not fire up

  1. Declare your jQuery between <script> and </script> in the <head>,
  2. Wrap your .scroll() event within
$(document).ready(function(){
  //do something
});

How to convert date to timestamp?

It should have been in this standard date format YYYY-MM-DD, to use below equation. You may have time along with example: 2020-04-24 16:51:56 or 2020-04-24T16:51:56+05:30. It will work fine but date format should like this YYYY-MM-DD only.

var myDate = "2020-04-24";
var timestamp = +new Date(myDate)

Using array map to filter results with if conditional

You should use Array.prototype.reduce to do this. I did do a little JS perf test to verify that this is more performant than doing a .filter + .map.

$scope.appIds = $scope.applicationsHere.reduce(function(ids, obj){
    if(obj.selected === true){
        ids.push(obj.id);
    }
    return ids;
}, []);

Just for the sake of clarity, here's the sample .reduce I used in the JSPerf test:

_x000D_
_x000D_
  var things = [_x000D_
    {id: 1, selected: true},_x000D_
    {id: 2, selected: true},_x000D_
    {id: 3, selected: true},_x000D_
    {id: 4, selected: true},_x000D_
    {id: 5, selected: false},_x000D_
    {id: 6, selected: true},_x000D_
    {id: 7, selected: false},_x000D_
    {id: 8, selected: true},_x000D_
    {id: 9, selected: false},_x000D_
    {id: 10, selected: true},_x000D_
  ];_x000D_
  _x000D_
   _x000D_
var ids = things.reduce((ids, thing) => {_x000D_
  if (thing.selected) {_x000D_
    ids.push(thing.id);_x000D_
  }_x000D_
  return ids;_x000D_
}, []);_x000D_
_x000D_
console.log(ids)
_x000D_
_x000D_
_x000D_


EDIT 1

Note, As of 2/2018 Reduce + Push is fastest in Chrome and Edge, but slower than Filter + Map in Firefox

How do I sort a list of dictionaries by a value of the dictionary?

If you do not need the original list of dictionaries, you could modify it in-place with sort() method using a custom key function.

Key function:

def get_name(d):
    """ Return the value of a key in a dictionary. """

    return d["name"]

The list to be sorted:

data_one = [{'name': 'Homer', 'age': 39}, {'name': 'Bart', 'age': 10}]

Sorting it in-place:

data_one.sort(key=get_name)

If you need the original list, call the sorted() function passing it the list and the key function, then assign the returned sorted list to a new variable:

data_two = [{'name': 'Homer', 'age': 39}, {'name': 'Bart', 'age': 10}]
new_data = sorted(data_two, key=get_name)

Printing data_one and new_data.

>>> print(data_one)
[{'name': 'Bart', 'age': 10}, {'name': 'Homer', 'age': 39}]
>>> print(new_data)
[{'name': 'Bart', 'age': 10}, {'name': 'Homer', 'age': 39}]

SELECT only rows that contain only alphanumeric characters in MySQL

Change the REGEXP to Like

SELECT * FROM table_name WHERE column_name like '%[^a-zA-Z0-9]%'

this one works fine

How can I get a web site's favicon?

In 2020, using duckduckgo.com's service from the CLI

curl -v https://icons.duckduckgo.com/ip2/<website>.ico > favicon.ico

Example

curl -v https://icons.duckduckgo.com/ip2/www.cdc.gov.ico > favicon.ico

Does Spring @Transactional attribute work on a private method?

Spring Docs explain that

In proxy mode (which is the default), only external method calls coming in through the proxy are intercepted. This means that self-invocation, in effect, a method within the target object calling another method of the target object, will not lead to an actual transaction at runtime even if the invoked method is marked with @Transactional.

Consider the use of AspectJ mode (see mode attribute in table below) if you expect self-invocations to be wrapped with transactions as well. In this case, there will not be a proxy in the first place; instead, the target class will be weaved (that is, its byte code will be modified) in order to turn @Transactional into runtime behavior on any kind of method.

Another way is user BeanSelfAware

Self Join to get employee manager name

SELECT e1.empno EmployeeId, e1.ename EmployeeName, 
       e1.mgr ManagerId, e2.ename AS ManagerName
FROM   emp e1, emp e2
       where e1.mgr = e2.empno

Illegal mix of collations MySQL Error

I had my table originally created with CHARSET=latin1. After table conversion to utf8 some columns were not converted, however that was not really obvious. You can try to run SHOW CREATE TABLE my_table; and see which column was not converted or just fix incorrect character set on problematic column with query below (change varchar length and CHARSET and COLLATE according to your needs):

 ALTER TABLE `my_table` CHANGE `my_column` `my_column` VARCHAR(10) CHARSET utf8 
 COLLATE utf8_general_ci NULL;

Angular 2 change event on every keypress

The secret event that keeps angular ngModel synchronous is the event call input. Hence the best answer to your question should be:

<input type="text" [(ngModel)]="mymodel" (input)="valuechange($event)" />
{{mymodel}}

How do you replace double quotes with a blank space in Java?

You don't need regex for this. Just a character-by-character replace is sufficient. You can use String#replace() for this.

String replaced = original.replace("\"", " ");

Note that you can also use an empty string "" instead to replace with. Else the spaces would double up.

String replaced = original.replace("\"", "");

Swift Open Link in Safari

since iOS 10 you should use:

guard let url = URL(string: linkUrlString) else {
    return
}
    
if #available(iOS 10.0, *) {
    UIApplication.shared.open(url, options: [:], completionHandler: nil)
} else {
    UIApplication.shared.openURL(url)
}

How can I print using JQuery

Hey If you want to print selected area or div ,Try This.

<style type="text/css">
@media print
{
body * { visibility: hidden; }
.div2 * { visibility: visible; }
.div2 { position: absolute; top: 40px; left: 30px; }
}
</style>

Hope it helps you

Create or update mapping in elasticsearch

In later Elasticsearch versions (7.x), types were removed. Updating a mapping can becomes:

curl -XPUT "http://localhost:9200/test/_mapping" -H 'Content-Type: application/json' -d'{
  "properties": {
    "new_geo_field": {
      "type": "geo_point"
    }
  }
}'

As others have pointed out, if the field exists, you typically have to reindex. There are exceptions, such as adding a new sub-field or changing analysis settings.

You can't "create a mapping", as the mapping is created with the index. Typically, you'd define the mapping when creating the index (or via index templates):

curl -XPUT "http://localhost:9200/test" -H 'Content-Type: application/json' -d'{
  "mappings": {
    "properties": {
      "foo_field": {
        "type": "text"
      }
    }
  }
}'

That's because, in production at least, you'd want to avoid letting Elasticsearch "guess" new fields. Which is what generated this question: geo data was read as an array of long values.

Maven build debug in Eclipse

if you are using Maven 2.0.8+, then it will be very simple, run mvndebug from the console, and connect to it via Remote Debug Java Application with port 8000.

jquery .html() vs .append()

if by .add you mean .append, then the result is the same if #myDiv is empty.

is the performance the same? dont know.

.html(x) ends up doing the same thing as .empty().append(x)

How do I store and retrieve a blob from sqlite?

I ended up with this method for inserting a blob:

   protected Boolean updateByteArrayInTable(String table, String value, byte[] byteArray, String expr)
   {
      try
      {
         SQLiteCommand mycommand = new SQLiteCommand(connection);
         mycommand.CommandText = "update " + table + " set " + value + "=@image" + " where " + expr;
         SQLiteParameter parameter = new SQLiteParameter("@image", System.Data.DbType.Binary);
         parameter.Value = byteArray;
         mycommand.Parameters.Add(parameter);

         int rowsUpdated = mycommand.ExecuteNonQuery();
         return (rowsUpdated>0);
      }
      catch (Exception)
      {
         return false;
      }
   }

For reading it back the code is:

   protected DataTable executeQuery(String command)
   {
      DataTable dt = new DataTable();
      try
      {
         SQLiteCommand mycommand = new SQLiteCommand(connection);
         mycommand.CommandText = command;
         SQLiteDataReader reader = mycommand.ExecuteReader();
         dt.Load(reader);
         reader.Close();
         return dt;
      }
      catch (Exception)
      {
         return null;
      }
   }

   protected DataTable getAllWhere(String table, String sort, String expr)
   {
      String cmd = "select * from " + table;
      if (sort != null)
         cmd += " order by " + sort;
      if (expr != null)
         cmd += " where " + expr;
      DataTable dt = executeQuery(cmd);
      return dt;
   }

   public DataRow getImage(long rowId) {
      String where = KEY_ROWID_IMAGE + " = " + Convert.ToString(rowId);
      DataTable dt = getAllWhere(DATABASE_TABLE_IMAGES, null, where);
      DataRow dr = null;
      if (dt.Rows.Count > 0) // should be just 1 row
         dr = dt.Rows[0];
      return dr;
   }

   public byte[] getImage(DataRow dr) {
      try
      {
         object image = dr[KEY_IMAGE];
         if (!Convert.IsDBNull(image))
            return (byte[])image;
         else
            return null;
      } catch(Exception) {
         return null;
      }
   }

   DataRow dri = getImage(rowId);
   byte[] image = getImage(dri);

How to delete node from XML file using C#

It may be easier to use XPath to locate the nodes that you wish to delete. This stackoverflow thread might give you some ideas.

In your case you will find the four nodes that you want using this expression:

XmlDocument doc = new XmlDocument();
doc.Load(fileName);
XmlNodeList nodes = doc.SelectNodes("//Setting[@name='File1']");

No increment operator (++) in Ruby?

I don't think that notation is available because—unlike say PHP or C—everything in Ruby is an object.

Sure you could use $var=0; $var++ in PHP, but that's because it's a variable and not an object. Therefore, $var = new stdClass(); $var++ would probably throw an error.

I'm not a Ruby or RoR programmer, so I'm sure someone can verify the above or rectify it if it's inaccurate.

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();
      }
    });

Get index of element as child relative to parent

Delegate and Live are easy to use but if you won't have any more li:s added dynamically you could use event delagation with normal bind/click as well. There should be some performance gain using this method since the DOM won't have to be monitored for new matching elements. Haven't got any actual numbers but it makes sense :)

$("#wizard").click(function (e) {
    var source = $(e.target);
    if(source.is("li")){
        // alert index of li relative to ul parent
        alert(source.index());
    }
});

You could test it at jsFiddle: http://jsfiddle.net/jimmysv/4Sfdh/1/

jQuery to remove an option from drop down list, given option's text/value

$("option[value='foo']").remove();

or better (if you have few selects in the page):

$("#select_id option[value='foo']").remove();

How can I wait In Node.js (JavaScript)? l need to pause for a period of time

The other answers are great but I thought I'd take a different tact.

If all you are really looking for is to slow down a specific file in linux:

 rm slowfile; mkfifo slowfile; perl -e 'select STDOUT; $| = 1; while(<>) {print $_; sleep(1) if (($ii++ % 5) == 0); }' myfile > slowfile  &

node myprog slowfile

This will sleep 1 sec every five lines. The node program will go as slow as the writer. If it is doing other things they will continue at normal speed.

The mkfifo creates a first-in-first-out pipe. It's what makes this work. The perl line will write as fast as you want. The $|=1 says don't buffer the output.

How can I tell if a Java integer is null?

parseInt() is just going to throw an exception if the parsing can't complete successfully. You can instead use Integers, the corresponding object type, which makes things a little bit cleaner. So you probably want something closer to:

Integer s = null;

try { 
  s = Integer.valueOf(startField.getText());
}
catch (NumberFormatException e) {
  // ...
}

if (s != null) { ... }

Beware if you do decide to use parseInt()! parseInt() doesn't support good internationalization, so you have to jump through even more hoops:

try {
    NumberFormat nf = NumberFormat.getIntegerInstance(locale);
    nf.setParseIntegerOnly(true);
    nf.setMaximumIntegerDigits(9); // Or whatever you'd like to max out at.

    // Start parsing from the beginning.
    ParsePosition p = new ParsePosition(0);

    int val = format.parse(str, p).intValue();
    if (p.getIndex() != str.length()) {
        // There's some stuff after all the digits are done being processed.
    }

    // Work with the processed value here.
} catch (java.text.ParseFormatException exc) {
    // Something blew up in the parsing.
}

what is the most efficient way of counting occurrences in pandas?

When you want to count the frequency of categorical data in a column in pandas dataFrame use: df['Column_Name'].value_counts()

-Source.

Reading content from URL with Node.js

A slightly modified version of @sidanmor 's code. The main point is, not every webpage is purely ASCII, user should be able to handle the decoding manually (even encode into base64)

function httpGet(url) {
  return new Promise((resolve, reject) => {
    const http = require('http'),
      https = require('https');

    let client = http;

    if (url.toString().indexOf("https") === 0) {
      client = https;
    }

    client.get(url, (resp) => {
      let chunks = [];

      // A chunk of data has been recieved.
      resp.on('data', (chunk) => {
        chunks.push(chunk);
      });

      // The whole response has been received. Print out the result.
      resp.on('end', () => {
        resolve(Buffer.concat(chunks));
      });

    }).on("error", (err) => {
      reject(err);
    });
  });
}

(async(url) => {
  var buf = await httpGet(url);
  console.log(buf.toString('utf-8'));
})('https://httpbin.org/headers');

Java collections convert a string to a list of characters

The lack of a good way to convert between a primitive array and a collection of its corresponding wrapper type is solved by some third party libraries. Guava, a very common one, has a convenience method to do the conversion:

List<Character> characterList = Chars.asList("abc".toCharArray());
Set<Character> characterSet = new HashSet<Character>(characterList);

The source was not found, but some or all event logs could not be searched. Inaccessible logs: Security

Locally I run visual studio with admin rights and the error was gone.

If you get this error in task scheduler you have to check the option run with high privileges.

'git' is not recognized as an internal or external command

  1. Search for GitHubDesktop\app-2.5.0\resources\app\git\cmd
  2. Open the File
  3. Copy File location.
  4. Search for environment.
  5. open edit system environment variable.
  6. open Environment Variables.
  7. on user variable double-click on Path.
  8. click on new
  9. past
  10. OK
  11. Open path on system variables.
  12. New, past the add \ (backslash), then OK
  13. Search for GitHubDesktop\app-2.5.0\resources\app\git\usr\bin\ 14 Copy the Address again and repeat pasting from step 4 to 12.

Connecting to TCP Socket from browser using javascript

As for your problem, currently you will have to depend on XHR or websockets for this.

Currently no popular browser has implemented any such raw sockets api for javascript that lets you create and access raw sockets, but a draft for the implementation of raw sockets api in JavaScript is under-way. Have a look at these links:
http://www.w3.org/TR/raw-sockets/
https://developer.mozilla.org/en-US/docs/Web/API/TCPSocket

Chrome now has support for raw TCP and UDP sockets in its ‘experimental’ APIs. These features are only available for extensions and, although documented, are hidden for the moment. Having said that, some developers are already creating interesting projects using it, such as this IRC client.

To access this API, you’ll need to enable the experimental flag in your extension’s manifest. Using sockets is pretty straightforward, for example:

chrome.experimental.socket.create('tcp', '127.0.0.1', 8080, function(socketInfo) {
  chrome.experimental.socket.connect(socketInfo.socketId, function (result) {
        chrome.experimental.socket.write(socketInfo.socketId, "Hello, world!");         
    });
});

Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 71 bytes)

WordPress overrides PHP's memory limit to 256M, with the assumption that whatever it was set to before is going to be too low to render the dashboard. You can override this by defining WP_MAX_MEMORY_LIMIT in wp-config.php:

define( 'WP_MAX_MEMORY_LIMIT' , '512M' );

I agree with DanFromGermany, 256M is really a lot of memory for rendering a dashboard page. Changing the memory limit is really putting a bandage on the problem.

Transaction count after EXECUTE indicates a mismatching number of BEGIN and COMMIT statements. Previous count = 1, current count = 0

In my case, the error was being caused by a RETURN inside the BEGIN TRANSACTION. So I had something like this:

Begin Transaction
 If (@something = 'foo')
 Begin
     --- do some stuff
     Return
 End
commit

and it needs to be:

Begin Transaction
 If (@something = 'foo')
 Begin
     --- do some stuff
     Rollback Transaction ----- THIS WAS MISSING
     Return
 End
commit

How to save the output of a console.log(object) to a file?

Right click on object and saving was not available for me.

The working solution for me is given below

Log as pretty string shown in this answer

console.log('jsonListBeauty', JSON.stringify(jsonList, null, 2));

in Chrome DevTools, Log shows as below

saveJsonlog

Just press Copy, It will be copied to clipboard with desired spacing level

Paste it on your favorite text editor and save it


image took on 15/02/2021, Google Chrome Version 88.0.4324.150

Duplicate ID, tag null, or parent id with another fragment for com.google.android.gms.maps.MapFragment

In this solution you do not need to take static variable;

Button nextBtn;

private SupportMapFragment mMapFragment;

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    super.onCreateView(inflater, container, savedInstanceState);

    if (mRootView != null) {
        ViewGroup parent = (ViewGroup) mRootView.getParent();
        Utility.log(0,"removeView","mRootView not NULL");
        if (parent != null) {
            Utility.log(0, "removeView", "view removeViewed");
            parent.removeAllViews();
        }
    }
    else {
        try {
            mRootView = inflater.inflate(R.layout.dummy_fragment_layout_one, container, false);//
        } catch (InflateException e) {
    /* map is already there, just return view as it is  */
            e.printStackTrace();
        }
    }

    return  mRootView;
}

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    FragmentManager fm = getChildFragmentManager();
    SupportMapFragment mapFragment = (SupportMapFragment) fm.findFragmentById(R.id.mapView);
    if (mapFragment == null) {
        mapFragment = new SupportMapFragment();
        FragmentTransaction ft = fm.beginTransaction();
        ft.add(R.id.mapView, mapFragment, "mapFragment");
        ft.commit();
        fm.executePendingTransactions();
    }
    //mapFragment.getMapAsync(this);
    nextBtn = (Button) view.findViewById(R.id.nextBtn);
    nextBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Utility.replaceSupportFragment(getActivity(),R.id.dummyFragment,dummyFragment_2.class.getSimpleName(),null,new dummyFragment_2());
        }
    });

}`

What should every programmer know about security?

Rule #1 of security for programmers: Don't roll your own

Unless you are yourself a security expert and/or cryptographer, always use a well-designed, well-tested, and mature security platform, framework, or library to do the work for you. These things have spent years being thought out, patched, updated, and examined by experts and hackers alike. You want to gain those advantages, not dismiss them by trying to reinvent the wheel.

Now, that's not to say you don't need to learn anything about security. You certainly need to know enough to understand what you're doing and make sure you're using the tools correctly. However, if you ever find yourself about to start writing your own cryptography algorithm, authentication system, input sanitizer, etc, stop, take a step back, and remember rule #1.

Heap vs Binary Search Tree (BST)

Summary

          Type      BST (*)   Heap
Insert    average   log(n)    1
Insert    worst     log(n)    log(n) or n (***)
Find any  worst     log(n)    n
Find max  worst     1 (**)    1
Create    worst     n log(n)  n
Delete    worst     log(n)    log(n)

All average times on this table are the same as their worst times except for Insert.

  • *: everywhere in this answer, BST == Balanced BST, since unbalanced sucks asymptotically
  • **: using a trivial modification explained in this answer
  • ***: log(n) for pointer tree heap, n for dynamic array heap

Advantages of binary heap over a BST

  • average time insertion into a binary heap is O(1), for BST is O(log(n)). This is the killer feature of heaps.

    There are also other heaps which reach O(1) amortized (stronger) like the Fibonacci Heap, and even worst case, like the Brodal queue, although they may not be practical because of non-asymptotic performance: Are Fibonacci heaps or Brodal queues used in practice anywhere?

  • binary heaps can be efficiently implemented on top of either dynamic arrays or pointer-based trees, BST only pointer-based trees. So for the heap we can choose the more space efficient array implementation, if we can afford occasional resize latencies.

  • binary heap creation is O(n) worst case, O(n log(n)) for BST.

Advantage of BST over binary heap

  • search for arbitrary elements is O(log(n)). This is the killer feature of BSTs.

    For heap, it is O(n) in general, except for the largest element which is O(1).

"False" advantage of heap over BST

  • heap is O(1) to find max, BST O(log(n)).

    This is a common misconception, because it is trivial to modify a BST to keep track of the largest element, and update it whenever that element could be changed: on insertion of a larger one swap, on removal find the second largest. Can we use binary search tree to simulate heap operation? (mentioned by Yeo).

    Actually, this is a limitation of heaps compared to BSTs: the only efficient search is that for the largest element.

Average binary heap insert is O(1)

Sources:

Intuitive argument:

  • bottom tree levels have exponentially more elements than top levels, so new elements are almost certain to go at the bottom
  • heap insertion starts from the bottom, BST must start from the top

In a binary heap, increasing the value at a given index is also O(1) for the same reason. But if you want to do that, it is likely that you will want to keep an extra index up-to-date on heap operations How to implement O(logn) decrease-key operation for min-heap based Priority Queue? e.g. for Dijkstra. Possible at no extra time cost.

GCC C++ standard library insert benchmark on real hardware

I benchmarked the C++ std::set (Red-black tree BST) and std::priority_queue (dynamic array heap) insert to see if I was right about the insert times, and this is what I got:

enter image description here

  • benchmark code
  • plot script
  • plot data
  • tested on Ubuntu 19.04, GCC 8.3.0 in a Lenovo ThinkPad P51 laptop with CPU: Intel Core i7-7820HQ CPU (4 cores / 8 threads, 2.90 GHz base, 8 MB cache), RAM: 2x Samsung M471A2K43BB1-CRC (2x 16GiB, 2400 Mbps), SSD: Samsung MZVLB512HAJQ-000L7 (512GB, 3,000 MB/s)

So clearly:

  • heap insert time is basically constant.

    We can clearly see dynamic array resize points. Since we are averaging every 10k inserts to be able to see anything at all above system noise, those peaks are in fact about 10k times larger than shown!

    The zoomed graph excludes essentially only the array resize points, and shows that almost all inserts fall under 25 nanoseconds.

  • BST is logarithmic. All inserts are much slower than the average heap insert.

  • BST vs hashmap detailed analysis at: What data structure is inside std::map in C++?

GCC C++ standard library insert benchmark on gem5

gem5 is a full system simulator, and therefore provides an infinitely accurate clock with with m5 dumpstats. So I tried to use it to estimate timings for individual inserts.

enter image description here

Interpretation:

  • heap is still constant, but now we see in more detail that there are a few lines, and each higher line is more sparse.

    This must correspond to memory access latencies are done for higher and higher inserts.

  • TODO I can't really interpret the BST fully one as it does not look so logarithmic and somewhat more constant.

    With this greater detail however we can see can also see a few distinct lines, but I'm not sure what they represent: I would expect the bottom line to be thinner, since we insert top bottom?

Benchmarked with this Buildroot setup on an aarch64 HPI CPU.

BST cannot be efficiently implemented on an array

Heap operations only need to bubble up or down a single tree branch, so O(log(n)) worst case swaps, O(1) average.

Keeping a BST balanced requires tree rotations, which can change the top element for another one, and would require moving the entire array around (O(n)).

Heaps can be efficiently implemented on an array

Parent and children indexes can be computed from the current index as shown here.

There are no balancing operations like BST.

Delete min is the most worrying operation as it has to be top down. But it can always be done by "percolating down" a single branch of the heap as explained here. This leads to an O(log(n)) worst case, since the heap is always well balanced.

If you are inserting a single node for every one you remove, then you lose the advantage of the asymptotic O(1) average insert that heaps provide as the delete would dominate, and you might as well use a BST. Dijkstra however updates nodes several times for each removal, so we are fine.

Dynamic array heaps vs pointer tree heaps

Heaps can be efficiently implemented on top of pointer heaps: Is it possible to make efficient pointer-based binary heap implementations?

The dynamic array implementation is more space efficient. Suppose that each heap element contains just a pointer to a struct:

  • the tree implementation must store three pointers for each element: parent, left child and right child. So the memory usage is always 4n (3 tree pointers + 1 struct pointer).

    Tree BSTs would also need further balancing information, e.g. black-red-ness.

  • the dynamic array implementation can be of size 2n just after a doubling. So on average it is going to be 1.5n.

On the other hand, the tree heap has better worst case insert, because copying the backing dynamic array to double its size takes O(n) worst case, while the tree heap just does new small allocations for each node.

Still, the backing array doubling is O(1) amortized, so it comes down to a maximum latency consideration. Mentioned here.

Philosophy

  • BSTs maintain a global property between a parent and all descendants (left smaller, right bigger).

    The top node of a BST is the middle element, which requires global knowledge to maintain (knowing how many smaller and larger elements are there).

    This global property is more expensive to maintain (log n insert), but gives more powerful searches (log n search).

  • Heaps maintain a local property between parent and direct children (parent > children).

    The top node of a heap is the big element, which only requires local knowledge to maintain (knowing your parent).

Comparing BST vs Heap vs Hashmap:

  • BST: can either be either a reasonable:

    • unordered set (a structure that determines if an element was previously inserted or not). But hashmap tends to be better due to O(1) amortized insert.
    • sorting machine. But heap is generally better at that, which is why heapsort is much more widely known than tree sort
  • heap: is just a sorting machine. Cannot be an efficient unordered set, because you can only check for the smallest/largest element fast.

  • hash map: can only be an unordered set, not an efficient sorting machine, because the hashing mixes up any ordering.

Doubly-linked list

A doubly linked list can be seen as subset of the heap where first item has greatest priority, so let's compare them here as well:

  • insertion:
    • position:
      • doubly linked list: the inserted item must be either the first or last, as we only have pointers to those elements.
      • binary heap: the inserted item can end up in any position. Less restrictive than linked list.
    • time:
      • doubly linked list: O(1) worst case since we have pointers to the items, and the update is really simple
      • binary heap: O(1) average, thus worse than linked list. Tradeoff for having more general insertion position.
  • search: O(n) for both

An use case for this is when the key of the heap is the current timestamp: in that case, new entries will always go to the beginning of the list. So we can even forget the exact timestamp altogether, and just keep the position in the list as the priority.

This can be used to implement an LRU cache. Just like for heap applications like Dijkstra, you will want to keep an additional hashmap from the key to the corresponding node of the list, to find which node to update quickly.

Comparison of different Balanced BST

Although the asymptotic insert and find times for all data structures that are commonly classified as "Balanced BSTs" that I've seen so far is the same, different BBSTs do have different trade-offs. I haven't fully studied this yet, but it would be good to summarize these trade-offs here:

  • Red-black tree. Appears to be the most commonly used BBST as of 2019, e.g. it is the one used by the GCC 8.3.0 C++ implementation
  • AVL tree. Appears to be a bit more balanced than BST, so it could be better for find latency, at the cost of slightly more expensive finds. Wiki summarizes: "AVL trees are often compared with red–black trees because both support the same set of operations and take [the same] time for the basic operations. For lookup-intensive applications, AVL trees are faster than red–black trees because they are more strictly balanced. Similar to red–black trees, AVL trees are height-balanced. Both are, in general, neither weight-balanced nor mu-balanced for any mu < 1/2; that is, sibling nodes can have hugely differing numbers of descendants."
  • WAVL. The original paper mentions advantages of that version in terms of bounds on rebalancing and rotation operations.

See also

Similar question on CS: https://cs.stackexchange.com/questions/27860/whats-the-difference-between-a-binary-search-tree-and-a-binary-heap

Possible reasons for timeout when trying to access EC2 instance

To enable ssh access from the Internet for instances in a VPC subnet do the following:

  • Attach an Internet gateway to your VPC.
  • Ensure that your subnet's route table points to the Internet gateway.
  • Ensure that instances in your subnet have a globally unique IP address (public IPv4 address, Elastic IP address, or IPv6 address).
  • Ensure that your network access control (at VPC Level) and security group rules (at ec2 level) allow the relevant traffic to flow to and from your instance. Ensure your network Public IP address is enabled for both. By default, Network AcL allow all inbound and outbound traffic except explicitly configured otherwise

Error: JavaFX runtime components are missing, and are required to run this application with JDK 11

This worked for me:

File >> Project Structure >> Modules >> Dependency >> + (on left-side of window)

clicking the "+" sign will let you designate the directory where you have unpacked JavaFX's "lib" folder.

Scope is Compile (which is the default.) You can then edit this to call it JavaFX by double-clicking on the line.

then in:

Run >> Edit Configurations

Add this line to VM Options:

--module-path /path/to/JavaFX/lib --add-modules=javafx.controls

(oh and don't forget to set the SDK)

Border for an Image view in Android?

Just add this code in your ImageView:

<?xml version="1.0" encoding="utf-8"?>
<shape
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">

    <solid
        android:color="@color/white"/>

    <size
        android:width="20dp"
        android:height="20dp"/>
    <stroke
        android:width="4dp" android:color="@android:color/black"/>
    <padding android:left="1dp" android:top="1dp" android:right="1dp"
        android:bottom="1dp" />
</shape>

change PATH permanently on Ubuntu

Assuming you want to add this path for all users on the system, add the following line to your /etc/profile.d/play.sh (and possibly play.csh, etc):

PATH=$PATH:/home/me/play
export PATH

case in sql stored procedure on SQL Server

CASE isn't used for flow control... for this, you would need to use IF...

But, there's a set-based solution to this problem instead of the procedural approach:

UPDATE tblEmployee
SET 
  InOffice = CASE WHEN @NewStatus = 'InOffice' THEN -1 ELSE InOffice END,
  OutOffice = CASE WHEN @NewStatus = 'OutOffice' THEN -1 ELSE OutOffice END,
  Home = CASE WHEN @NewStatus = 'Home' THEN -1 ELSE Home END
WHERE EmpID = @EmpID

Note that the ELSE will preserves the original value if the @NewStatus condition isn't met.

How to detect if a string contains at least a number?

  1. You could use CLR based UDFs or do a CONTAINS query using all the digits on the search column.

Reference - What does this error mean in PHP?

Warning: open_basedir restriction in effect

This warning can appear with various functions that are related to file and directory access. It warns about a configuration issue.

When it appears, it means that access has been forbidden to some files.

The warning itself does not break anything, but most often a script does not properly work if file-access is prevented.

The fix is normally to change the PHP configuration, the related setting is called open_basedir.

Sometimes the wrong file or directory names are used, the fix is then to use the right ones.

Related Questions:

Opening a .ipynb.txt File

I used to read jupiter nb files with this code:

import codecs
import json

f = codecs.open("JupFileName.ipynb", 'r')
source = f.read()

y = json.loads(source)
pySource = '##Python code from jpynb:\n'
for x in y['cells']:
     for x2 in x['source']:
         pySource = pySource + x2
         if x2[-1] != '\n':
            pySource = pySource + '\n'
print(pySource)

Appending the same string to a list of strings in Python

The simplest way to do this is with a list comprehension:

[s + mystring for s in mylist]

Notice that I avoided using builtin names like list because that shadows or hides the builtin names, which is very much not good.

Also, if you do not actually need a list, but just need an iterator, a generator expression can be more efficient (although it does not likely matter on short lists):

(s + mystring for s in mylist)

These are very powerful, flexible, and concise. Every good python programmer should learn to wield them.

Remove last 3 characters of string or number in javascript

Here is an approach using str.slice(0, -n). Where n is the number of characters you want to truncate.

_x000D_
_x000D_
var str = 1437203995000;_x000D_
str = str.toString();_x000D_
console.log("Original data: ",str);_x000D_
str = str.slice(0, -3);_x000D_
str = parseInt(str);_x000D_
console.log("After truncate: ",str);
_x000D_
_x000D_
_x000D_

RESTful URL design for search

In addition i would also suggest:

/cars/search/all{?color,model,year}
/cars/search/by-parameters{?color,model,year}
/cars/search/by-vendor{?vendor}

Here, Search is considered as a child resource of Cars resource.

How do you take a git diff file, and apply it to a local branch that is a copy of the same repository?

It seems like you can also use the patch command. Put the diff in the root of the repository and run patch from the command line.

patch -i yourcoworkers.diff

or

patch -p0 -i yourcoworkers.diff

You may need to remove the leading folder structure if they created the diff without using --no-prefix.

If so, then you can remove the parts of the folder that don't apply using:

patch -p1 -i yourcoworkers.diff

The -p(n) signifies how many parts of the folder structure to remove.

More information on creating and applying patches here.

You can also use

git apply yourcoworkers.diff --stat 

to see if the diff by default will apply any changes. It may say 0 files affected if the patch is not applied correctly (different folder structure).

python - checking odd/even numbers and changing outputs on number size

1. another odd testing function

Ok, the assignment was handed in 8+ years ago, but here is another solution based on bit shifting operations:

def isodd(i):
    return(bool(i>>0&1))

testing gives:

>>> isodd(2)
False
>>> isodd(3)
True
>>> isodd(4)
False

2. Nearest Odd number alternative approach

However, instead of a code that says "give me this precise input (an integer odd number) or otherwise I won't do anything" I also like robust codes that say, "give me a number, any number, and I'll give you the nearest pyramid to that number".

In that case this function is helpful, and gives you the nearest odd (e.g. any number f such that 6<=f<8 is set to 7 and so on.)

def nearodd(f):
    return int(f/2)*2+1

Example output:

nearodd(4.9)
5

nearodd(7.2)
7

nearodd(8)
9  

How to create a signed APK file using Cordova command line interface?

Step 1:

D:\projects\Phonegap\Example> cordova plugin rm org.apache.cordova.console --save

add the --save so that it removes the plugin from the config.xml file.

Step 2:

To generate a release build for Android, we first need to make a small change to the AndroidManifest.xml file found in platforms/android. Edit the file and change the line:

<application android:debuggable="true" android:hardwareAccelerated="true" android:icon="@drawable/icon" android:label="@string/app_name">

and change android:debuggable to false:

<application android:debuggable="false" android:hardwareAccelerated="true" android:icon="@drawable/icon" android:label="@string/app_name">

As of cordova 6.2.0 remove the android:debuggable tag completely. Here is the explanation from cordova:

Explanation for issues of type "HardcodedDebugMode": It's best to leave out the android:debuggable attribute from the manifest. If you do, then the tools will automatically insert android:debuggable=true when building an APK to debug on an emulator or device. And when you perform a release build, such as Exporting APK, it will automatically set it to false.

If on the other hand you specify a specific value in the manifest file, then the tools will always use it. This can lead to accidentally publishing your app with debug information.

Step 3:

Now we can tell cordova to generate our release build:

D:\projects\Phonegap\Example> cordova build --release android

Then, we can find our unsigned APK file in platforms/android/ant-build. In our example, the file was platforms/android/ant-build/Example-release-unsigned.apk

Step 4:

Note : We have our keystore keystoreNAME-mobileapps.keystore in this Git Repo, if you want to create another, please proceed with the following steps.

Key Generation:

Syntax:

keytool -genkey -v -keystore <keystoreName>.keystore -alias <Keystore AliasName> -keyalg <Key algorithm> -keysize <Key size> -validity <Key Validity in Days>

Egs:

keytool -genkey -v -keystore NAME-mobileapps.keystore -alias NAMEmobileapps -keyalg RSA -keysize 2048 -validity 10000


keystore password? : xxxxxxx
What is your first and last name? :  xxxxxx
What is the name of your organizational unit? :  xxxxxxxx
What is the name of your organization? :  xxxxxxxxx
What is the name of your City or Locality? :  xxxxxxx
What is the name of your State or Province? :  xxxxx
What is the two-letter country code for this unit? :  xxx

Then the Key store has been generated with name as NAME-mobileapps.keystore

Step 5:

Place the generated keystore in

old version cordova

D:\projects\Phonegap\Example\platforms\android\ant-build

New version cordova

D:\projects\Phonegap\Example\platforms\android\build\outputs\apk

To sign the unsigned APK, run the jarsigner tool which is also included in the JDK:

Syntax:

jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore <keystorename> <Unsigned APK file> <Keystore Alias name>

Egs:

D:\projects\Phonegap\Example\platforms\android\ant-build> jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore NAME-mobileapps.keystore Example-release-unsigned.apk xxxxxmobileapps

OR

D:\projects\Phonegap\Example\platforms\android\build\outputs\apk> jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore NAME-mobileapps.keystore Example-release-unsigned.apk xxxxxmobileapps

Enter KeyPhrase as 'xxxxxxxx'

This signs the apk in place.

Step 6:

Finally, we need to run the zip align tool to optimize the APK:

D:\projects\Phonegap\Example\platforms\android\ant-build> zipalign -v 4 Example-release-unsigned.apk Example.apk 

OR

D:\projects\Phonegap\Example\platforms\android\ant-build> C:\Phonegap\adt-bundle-windows-x86_64-20140624\sdk\build-tools\android-4.4W\zipalign -v 4 Example-release-unsigned.apk Example.apk

OR

D:\projects\Phonegap\Example\platforms\android\build\outputs\apk> C:\Phonegap\adt-bundle-windows-x86_64-20140624\sdk\build-tools\android-4.4W\zipalign -v 4 Example-release-unsigned.apk Example.apk

Now we have our final release binary called example.apk and we can release this on the Google Play Store.

Subversion stuck due to "previous operation has not finished"?

I initially got this problem trying to check in with TortoiseSVN. Initially, both, TortoiseSVN clean up and console svn cleanup both failed with similar messages as the original poster.

But my solution, (found out accidentally) was just to wait a few minutes. I am thinking TSVNCache was holding on to some of those files at the time of check in.

How to fix Error: "Could not find schema information for the attribute/element" by creating schema

When this happened to me (out of nowhere) I was about to dive into the top answer above, and then I figured I'd close the project, close Visual Studio, and then re-open everything. Problem solved. VS bug?

Cassandra cqlsh - connection refused

Look for native_transport_port in /etc/cassandra/cassandra.yaml The default is 9842.

native_transport_port: 9842

For connecting to localhost with cqlsh, this port worked for me.

cqlsh 127.0.0.1 9842

Authenticate with GitHub using a token

By having struggling so many hours on applying GitHub token finally it works as below:

$ cf_export GITHUB_TOKEN=$(codefresh get context github --decrypt -o yaml | yq -y .spec.data.auth.password)

  • code follows Codefresh guidance on cloning a repo using token (freestyle}
  • test carried: sed %d%H%M on match word '-123456-whatever'
  • push back to the repo (which is private repo)
  • triggered by DockerHub webhooks

Following is the complete code:

version: '1.0'
steps:
  get_git_token:
    title: Reading Github token
    image: codefresh/cli
    commands:
      - cf_export GITHUB_TOKEN=$(codefresh get context github --decrypt -o yaml | yq -y .spec.data.auth.password)
  main_clone:
    title: Updating the repo
    image: alpine/git:latest
    commands:
      - git clone https://chetabahana:[email protected]/chetabahana/compose.git
      - cd compose && git remote rm origin
      - git config --global user.name "chetabahana"
      - git config --global user.email "[email protected]"
      - git remote add origin https://chetabahana:[email protected]/chetabahana/compose.git
      - sed -i "s/-[0-9]\{1,\}-\([a-zA-Z0-9_]*\)'/-`date +%d%H%M`-whatever'/g" cloudbuild.yaml
      - git status && git add . && git commit -m "fresh commit" && git push -u origin master

Output...

On branch master 
Changes not staged for commit: 
  (use "git add ..." to update what will be committed) 
  (use "git checkout -- ..." to discard changes in working directory) 

modified:   cloudbuild.yaml 

no changes added to commit (use "git add" and/or "git commit -a") 
[master dbab20f] fresh commit 
 1 file changed, 1 insertion(+), 1 deletion(-) 
Enumerating objects: 5, done. 
Counting objects:  20% (1/5) ...  Counting objects: 100% (5/5), done. 
Delta compression using up to 4 threads 
Compressing objects:  33% (1/3) ... Writing objects: 100% (3/3), 283 bytes | 283.00 KiB/s, done. 
Total 3 (delta 2), reused 0 (delta 0) 
remote: Resolving deltas:   0% (0/2)  ...   (2/2), completed with 2 local objects. 
To https://github.com/chetabahana/compose.git 
   bbb6d2f..dbab20f  master -> master 
Branch 'master' set up to track remote branch 'master' from 'origin'. 
Reading environment variable exporting file contents. 
Successfully ran freestyle step: Cloning the repo 

react-native :app:installDebug FAILED

This works for me

  1. Uninstall the app from your phone
  2. cd android
  3. gradlew clean
  4. cd ..
  5. react-native run-android

How to update Android Studio automatically?

These steps are for the people who already have Android Studio installed on their Windows machine >>>

Steps to download the update:

  1. Google for “Update android studio”
  2. Choose the result from “tools.android.com”
  3. Download the zip file (it’s around 500 MB).

Steps to install Android Studio from a .zip folder:

  1. Open the .zip folder using Windows Explorer.
  2. click on 'Extract all' (or 'Extract all files') option in the ribbon.
  3. Go to the extract location. And then to android-studio\bin and run studio.exe ifyou’re on 32bit OS, or studio64.exe if you’re on 64bit OS.

By then, the Andriod Studio should open and configure your uppdates enter image description here

Python: maximum recursion depth exceeded while calling a Python object

this turns the recursion in to a loop:

def checkNextID(ID):
    global numOfRuns, curRes, lastResult
    while ID < lastResult:
        try:
            numOfRuns += 1
            if numOfRuns % 10 == 0:
                time.sleep(3) # sleep every 10 iterations
            if isValid(ID + 8):
                parseHTML(curRes)
                ID = ID + 8
            elif isValid(ID + 18):
                parseHTML(curRes)
                ID = ID + 18
            elif isValid(ID + 7):
                parseHTML(curRes)
                ID = ID + 7
            elif isValid(ID + 17):
                parseHTML(curRes)
                ID = ID + 17
            elif isValid(ID+6):
                parseHTML(curRes)
                ID = ID + 6
            elif isValid(ID + 16):
                parseHTML(curRes)
                ID = ID + 16
            else:
                ID = ID + 1
        except Exception, e:
            print "somethin went wrong: " + str(e)

Is it a bad practice to use break in a for loop?

There is nothing inherently wrong with using a break statement but nested loops can get confusing. To improve readability many languages (at least Java does) support breaking to labels which will greatly improve readability.

int[] iArray = new int[]{0,1,2,3,4,5,6,7,8,9};
int[] jArray = new int[]{0,1,2,3,4,5,6,7,8,9};

// label for i loop
iLoop: for (int i = 0; i < iArray.length; i++) {

    // label for j loop
    jLoop: for (int j = 0; j < jArray.length; j++) {

        if(iArray[i] < jArray[j]){
            // break i and j loops
            break iLoop;
        } else if (iArray[i] > jArray[j]){  
            // breaks only j loop
            break jLoop;
        } else {
            // unclear which loop is ending
            // (breaks only the j loop)
            break;
        }
    }
}

I will say that break (and return) statements often increase cyclomatic complexity which makes it harder to prove code is doing the correct thing in all cases.

If you're considering using a break while iterating over a sequence for some particular item, you might want to reconsider the data structure used to hold your data. Using something like a Set or Map may provide better results.

How to spawn a process and capture its STDOUT in .NET?

I needed to capture both stdout and stderr and have it timeout if the process didn't exit when expected. I came up with this:

Process process = new Process();
StringBuilder outputStringBuilder = new StringBuilder();

try
{
process.StartInfo.FileName = exeFileName;
process.StartInfo.WorkingDirectory = args.ExeDirectory;
process.StartInfo.Arguments = args;
process.StartInfo.RedirectStandardError = true;
process.StartInfo.RedirectStandardOutput = true;
process.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
process.StartInfo.CreateNoWindow = true;
process.StartInfo.UseShellExecute = false;
process.EnableRaisingEvents = false;
process.OutputDataReceived += (sender, eventArgs) => outputStringBuilder.AppendLine(eventArgs.Data);
process.ErrorDataReceived += (sender, eventArgs) => outputStringBuilder.AppendLine(eventArgs.Data);
process.Start();
process.BeginOutputReadLine();
process.BeginErrorReadLine();
var processExited = process.WaitForExit(PROCESS_TIMEOUT);

if (processExited == false) // we timed out...
{
    process.Kill();
    throw new Exception("ERROR: Process took too long to finish");
}
else if (process.ExitCode != 0)
{
    var output = outputStringBuilder.ToString();
    var prefixMessage = "";

    throw new Exception("Process exited with non-zero exit code of: " + process.ExitCode + Environment.NewLine + 
    "Output from process: " + outputStringBuilder.ToString());
}
}
finally
{                
process.Close();
}

I am piping the stdout and stderr into the same string, but you could keep it separate if needed. It uses events, so it should handle them as they come (I believe). I have run this successfully, and will be volume testing it soon.

How do I give text or an image a transparent background using CSS?

background-color: rgba(255, 0, 0, 0.5); as mentioned above is the best answer simply put. To say use CSS 3, even in 2013, is not simple because the level of support from various browsers changes with every iteration.

While background-color is supported by all major browsers (not new to CSS 3) [1] the alpha transparency can be tricky, especially with Internet Explorer prior to version 9 and with border color on Safari prior to version 5.1. [2]

Using something like Compass or SASS can really help production and cross platform compatibility.


[1] W3Schools: CSS background-color Property

[2] Norman's Blog: Browser Support Checklist CSS3 (October 2012)

How can I switch to another branch in git?

The Best Command for changing branch

git branch -M YOUR_BRANCH

matrix multiplication algorithm time complexity

Using linear algebra, there exist algorithms that achieve better complexity than the naive O(n3). Solvay Strassen algorithm achieves a complexity of O(n2.807) by reducing the number of multiplications required for each 2x2 sub-matrix from 8 to 7.

The fastest known matrix multiplication algorithm is Coppersmith-Winograd algorithm with a complexity of O(n2.3737). Unless the matrix is huge, these algorithms do not result in a vast difference in computation time. In practice, it is easier and faster to use parallel algorithms for matrix multiplication.

How to request Administrator access inside a batch file

This script does the trick! Just paste it into the top of your bat file. If you want to review the output of your script, add a "pause" command at the bottom of your batch file.

UPDATE: This script is now slightly edited to support command line arguments and a 64 bit OS.

Thank you Eneerge @ https://sites.google.com/site/eneerge/scripts/batchgotadmin

@echo off

:: BatchGotAdmin
:-------------------------------------
REM  --> Check for permissions
    IF "%PROCESSOR_ARCHITECTURE%" EQU "amd64" (
>nul 2>&1 "%SYSTEMROOT%\SysWOW64\cacls.exe" "%SYSTEMROOT%\SysWOW64\config\system"
) ELSE (
>nul 2>&1 "%SYSTEMROOT%\system32\cacls.exe" "%SYSTEMROOT%\system32\config\system"
)

REM --> If error flag set, we do not have admin.
if '%errorlevel%' NEQ '0' (
    echo Requesting administrative privileges...
    goto UACPrompt
) else ( goto gotAdmin )

:UACPrompt
    echo Set UAC = CreateObject^("Shell.Application"^) > "%temp%\getadmin.vbs"
    set params= %*
    echo UAC.ShellExecute "cmd.exe", "/c ""%~s0"" %params:"=""%", "", "runas", 1 >> "%temp%\getadmin.vbs"

    "%temp%\getadmin.vbs"
    del "%temp%\getadmin.vbs"
    exit /B

:gotAdmin
    pushd "%CD%"
    CD /D "%~dp0"
:--------------------------------------    
    <YOUR BATCH SCRIPT HERE>

Java 8 lambda get and remove element from list

Combining my initial idea and your answers I reached what seems to be the solution to my own question:

public ProducerDTO findAndRemove(String pod) {
    ProducerDTO p = null;
    try {
        p = IntStream.range(0, producersProcedureActive.size())
             .filter(i -> producersProcedureActive.get(i).getPod().equals(pod))
             .boxed()
             .findFirst()
             .map(i -> producersProcedureActive.remove((int)i))
             .get();
        logger.debug(p);
    } catch (NoSuchElementException e) {
        logger.error("No producer found with POD [" + pod + "]");
    }
    return p;
}

It lets remove the object using remove(int) that do not traverse again the list (as suggested by @Tunaki) and it lets return the removed object to the function caller.

I read your answers that suggest me to choose safe methods like ifPresent instead of get but I do not find a way to use them in this scenario.

Are there any important drawback in this kind of solution?

Edit following @Holger advice

This should be the function I needed

public ProducerDTO findAndRemove(String pod) {
    return IntStream.range(0, producersProcedureActive.size())
            .filter(i -> producersProcedureActive.get(i).getPod().equals(pod))      
            .boxed()                                                                
            .findFirst()
            .map(i -> producersProcedureActive.remove((int)i))
            .orElseGet(() -> {
                logger.error("No producer found with POD [" + pod + "]"); 
                return null; 
            });
}

An exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll

use try-catch to see real error occurred on you

 try
{
  //Your insert code here
}
catch (System.Data.SqlClient.SqlException sqlException)
{
  System.Windows.Forms.MessageBox.Show(sqlException.Message);
}

How to recursively download a folder via FTP on Linux

ncftp -u <user> -p <pass> <server>
ncftp> mget directory

Getting time difference between two times in PHP

You can use strtotime() for time calculation. Here is an example:

$checkTime = strtotime('09:00:59');
echo 'Check Time : '.date('H:i:s', $checkTime);
echo '<hr>';

$loginTime = strtotime('09:01:00');
$diff = $checkTime - $loginTime;
echo 'Login Time : '.date('H:i:s', $loginTime).'<br>';
echo ($diff < 0)? 'Late!' : 'Right time!'; echo '<br>';
echo 'Time diff in sec: '.abs($diff);

echo '<hr>';

$loginTime = strtotime('09:00:59');
$diff = $checkTime - $loginTime;
echo 'Login Time : '.date('H:i:s', $loginTime).'<br>';
echo ($diff < 0)? 'Late!' : 'Right time!';

echo '<hr>';

$loginTime = strtotime('09:00:00');
$diff = $checkTime - $loginTime;
echo 'Login Time : '.date('H:i:s', $loginTime).'<br>';
echo ($diff < 0)? 'Late!' : 'Right time!';

Demo

Check the already-asked question - how to get time difference in minutes:

Subtract the past-most one from the future-most one and divide by 60.

Times are done in unix format so they're just a big number showing the number of seconds from January 1 1970 00:00:00 GMT

How to add smooth scrolling to Bootstrap's scroll spy function

with this code, the id will not appear on the link

    document.querySelectorAll('a[href^="#"]').forEach(anchor => {
        anchor.addEventListener('click', function (e) {
            e.preventDefault();

            document.querySelector(this.getAttribute('href')).scrollIntoView({
                behavior: 'smooth'
            });
        });
    });

Understanding the ngRepeat 'track by' expression

If you are working with objects track by the identifier(e.g. $index) instead of the whole object and you reload your data later, ngRepeat will not rebuild the DOM elements for items it has already rendered, even if the JavaScript objects in the collection have been substituted for new ones.

MySQL - UPDATE query based on SELECT Query

I found this question in looking for my own solution to a very complex join. This is an alternative solution, to a more complex version of the problem, which I thought might be useful.

I needed to populate the product_id field in the activities table, where activities are numbered in a unit, and units are numbered in a level (identified using a string ??N), such that one can identify activities using an SKU ie L1U1A1. Those SKUs are then stored in a different table.

I identified the following to get a list of activity_id vs product_id:-

SELECT a.activity_id, w.product_id 
  FROM activities a 
  JOIN units USING(unit_id) 
  JOIN product_types USING(product_type_id) 
  JOIN web_products w 
    ON sku=CONCAT('L',SUBSTR(product_type_code,3), 'U',unit_index, 'A',activity_index)

I found that that was too complex to incorporate into a SELECT within mysql, so I created a temporary table, and joined that with the update statement:-

CREATE TEMPORARY TABLE activity_product_ids AS (<the above select statement>);

UPDATE activities a
  JOIN activity_product_ids b
    ON a.activity_id=b.activity_id 
  SET a.product_id=b.product_id;

I hope someone finds this useful

How to use HTTP GET in PowerShell?

In PowerShell v3, have a look at the Invoke-WebRequest and Invoke-RestMethod e.g.:

$msg = Read-Host -Prompt "Enter message"
$encmsg = [System.Web.HttpUtility]::UrlEncode($msg)
Invoke-WebRequest -Uri "http://smsserver/SNSManager/msgSend.jsp?uid&to=smartsms:*+001XXXXXX&msg=$encmsg&encoding=windows-1255"

GZIPInputStream reading line by line

You can use the following method in a util class, and use it whenever necessary...

public static List<String> readLinesFromGZ(String filePath) {
    List<String> lines = new ArrayList<>();
    File file = new File(filePath);

    try (GZIPInputStream gzip = new GZIPInputStream(new FileInputStream(file));
            BufferedReader br = new BufferedReader(new InputStreamReader(gzip));) {
        String line = null;
        while ((line = br.readLine()) != null) {
            lines.add(line);
        }
    } catch (FileNotFoundException e) {
        e.printStackTrace(System.err);
    } catch (IOException e) {
        e.printStackTrace(System.err);
    }
    return lines;
}

Default password of mysql in ubuntu server 16.04

As of Ubuntu 20.04 with MySql 8.0 : the function PASSWORD do not exists any more, hence the right way is:

  1. login to mysql with sudo mysql -u root

  2. change the password:

USE mysql;
UPDATE user set authentication_string=NULL where User='root';
FLUSH privileges;
ALTER USER 'root'@'localhost' IDENTIFIED WITH caching_sha2_password BY 'My-N7w_And.5ecure-P@s5w0rd';
FLUSH privileges;
QUIT

now you should be able to login with mysql -u root -p (or to phpMyAdmin with username root) and your chosen password.

P,S:

You can also login with user debian-sys-maint, the password is in the file /etc/mysql/debian.cnf

Numpy how to iterate over columns of array?

Alternatively, you can use enumerate. It gives you the column number and the column values as well.

for num, column in enumerate(array.T):
    some_function(column) # column: Gives you the column value as asked in the question
    some_function(num) # num: Gives you the column number 


How to reformat JSON in Notepad++?

I know you asked about NotePad++ but TextMate for OS X can do it via the JSON bundle, its called the "Reformat Document" command.

Could not install packages due to a "Environment error :[error 13]: permission denied : 'usr/local/bin/f2py'"

As a windows user, run an Admin powershell and launch :

python -m pip install --upgrade pip

Placing/Overlapping(z-index) a view above another view in android

I use this, if you want only one view to be bring to front when needed:

containerView.bringChildToFront(topView);

containerView is container of views to be sorted, topView is view which i want to have as top most in container.

for multiple views to arrange is about to use setChildrenDrawingOrderEnabled(true) and overriding getChildDrawingOrder(int childCount, int i) as mentioned above.

Node.js - Maximum call stack size exceeded

I found a dirty solution:

/bin/bash -c "ulimit -s 65500; exec /usr/local/bin/node --stack-size=65500 /path/to/app.js"

It just increase call stack limit. I think that this is not suitable for production code, but I needed it for script that run only once.

nginx- duplicate default server error

In my case junk files from editor caused the problem. I had a config as below:

#...
http {
 # ...
 include ../sites/*;
}

In the ../sites directory initially I had a default.config file. However, by mistake I saved duplicate files as default.config.save and default.config.save.1. Removing them resolved the issue.

Checking if object is empty, works with ng-show but not from controller?

Use an empty object literal isn't necessary here, you can use null or undefined:

$scope.items = null;

In this way, ng-show should keep working, and in your controller you can just do:

if ($scope.items) {
    // items have value
} else {
    // items is still null
}

And in your $http callbacks, you do the following:

$http.get(..., function(data) {
    $scope.items = {
        data: data,
        // other stuff
    };
});

Case Function Equivalent in Excel

Recently I unfortunately had to work with Excel 2010 again for a while and I missed the SWITCH function a lot. I came up with the following to try to minimize my pain:

=CHOOSE(SUM((A1={"a";"b";"c"})*ROW(INDIRECT(1&":"&3))),1,2,3)
CTRL+SHIFT+ENTER

where A1 is where your condition lies (it could be a formula, whatever). The good thing is that we just have to provide the condition once (just like SWITCH) and the cases (in this example: a,b,c) and results (in this example: 1,2,3) are ordered, which makes it easy to reason about.

Here is how it works:

  • Cond={"c1";"c2";...;"cn"} returns a N-vector of TRUE or FALSE (with behaves like 1s and 0s)
  • ROW(INDIRECT(1&":"&n)) returns a N-vector of ordered numbers: 1;2;3;...;n
  • The multiplication of both vectors will return lots of zeros and a number (position) where the condition was matched
  • SUM just transforms this vector with zeros and a position into just a single number, which CHOOSE then can use
  • If you want to add another condition, just remember to increment the last number inside INDIRECT
  • If you want an ELSE case, just wrap it inside an IFERROR formula
  • The formula will not behave properly if you provide the same condition more than once, but I guess nobody would want to do that anyway

What's the difference between `raw_input()` and `input()` in Python 3?

If You want to ensure, that your code is running with python2 and python3, use function input () in your script and add this to begin of your script:

from sys import version_info
if version_info.major == 3:
    pass
elif version_info.major == 2:
    try:
        input = raw_input
    except NameError:
        pass
else:
    print ("Unknown python version - input function not safe")

Reliable way to convert a file to a byte[]

Not to repeat what everyone already have said but keep the following cheat sheet handly for File manipulations:

  1. System.IO.File.ReadAllBytes(filename);
  2. File.Exists(filename)
  3. Path.Combine(folderName, resOfThePath);
  4. Path.GetFullPath(path); // converts a relative path to absolute one
  5. Path.GetExtension(path);

Error: select command denied to user '<userid>'@'<ip-address>' for table '<table-name>'

For me, I accidentally included my local database name inside the SQL query, hence the access denied issue came up when I deployed.

I removed the database name from the SQL query and it got fixed.

Direct download from Google Drive using Google Drive API

Check this out:

wget https://raw.githubusercontent.com/circulosmeos/gdown.pl/master/gdown.pl
chmod +x gdown.pl
./gdown.pl https://drive.google.com/file/d/FILE_ID/view TARGET_PATH

finding multiples of a number in Python

Based on mathematical concepts, I understand that:

  • all natural numbers that, divided by n, having 0 as remainder, are all multiples of n

Therefore, the following calculation also applies as a solution (multiples between 1 and 100):

>>> multiples_5 = [n for n in range(1, 101) if n % 5 == 0]
>>> multiples_5
[5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100]

For further reading:

Value of type 'T' cannot be converted to

I know similar code that the OP posted in this question from generic parsers. From a performance perspective, you should use Unsafe.As<TFrom, TResult>(ref TFrom source), which can be found in the System.Runtime.CompilerServices.Unsafe NuGet package. It avoids boxing for value types in these scenarios. I also think that Unsafe.As results in less machine code produced by the JIT than casting twice (using (TResult) (object) actualString), but I haven't checked that out.

public TResult ParseSomething<TResult>(ParseContext context)
{
    if (typeof(TResult) == typeof(string))
    {
        var token = context.ParseNextToken();
        string parsedString = token.ParseToDotnetString();
        return Unsafe.As<string, TResult>(ref parsedString);
    }
    else if (typeof(TResult) == typeof(int))
    {
        var token = context.ParseNextToken();
        int parsedInt32 = token.ParseToDotnetInt32();
        // This will not box which might be critical to performance
        return Unsafe.As<int, TResult>(ref parsedInt32); 
    }
    // other cases omitted for brevity's sake
}

Unsafe.As will be replaced by the JIT with efficient machine code instructions, as you can see in the official CoreFX repo:

Source Code of Unsafe.As

Run Java Code Online

Some new java online compiler and runner:

  1. Java Launch
  2. Srikanthdaggumalli

These sites are in under development. But you can view the compilation errors, Runtime Exceptions as well as output of a java program by clicking on the TryItYourself link.

Get last 5 characters in a string

Checks for errors:

Dim result As String = str
If str.Length > 5 Then
    result = str.Substring(str.Length - 5)
End If

How to easily consume a web service from PHP

Well, those features are specific to a tool that you are using for development in those languages.

You wouldn't have those tools if (for example) you were using notepad to write code. So, maybe you should ask the question for the tool you are using.

For PHP: http://webservices.xml.com/pub/a/ws/2004/03/24/phpws.html

Ajax using https on an http page

Here's what I do:

Generate a hidden iFrame with the data you would like to post. Since you still control that iFrame, same origin does not apply. Then submit the form in that iFrame to the ssl page. The ssl page then redirects to a non-ssl page with status messages. You have access to the iFrame.

Getting the .Text value from a TextBox

Use this instead:

string objTextBox = t.Text;

The object t is the TextBox. The object you call objTextBox is assigned the ID property of the TextBox.

So better code would be:

TextBox objTextBox = (TextBox)sender;
string theText = objTextBox.Text;

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.

Ways to save enums in database

For a large database, I am reluctant to lose the size and speed advantages of the numeric representation. I often end up with a database table representing the Enum.

You can enforce database consistency by declaring a foreign key -- although in some cases it might be better to not declare that as a foreign key constraint, which imposes a cost on every transaction. You can ensure consistency by periodically doing a check, at times of your choosing, with:

SELECT reftable.* FROM reftable
  LEFT JOIN enumtable ON reftable.enum_ref_id = enumtable.enum_id
WHERE enumtable.enum_id IS NULL;

The other half of this solution is to write some test code that checks that the Java enum and the database enum table have the same contents. That's left as an exercise for the reader.

Adding default parameter value with type hint in Python

Your second way is correct.

def foo(opts: dict = {}):
    pass

print(foo.__annotations__)

this outputs

{'opts': <class 'dict'>}

It's true that's it's not listed in PEP 484, but type hints are an application of function annotations, which are documented in PEP 3107. The syntax section makes it clear that keyword arguments works with function annotations in this way.

I strongly advise against using mutable keyword arguments. More information here.

C string append

Consider using the great but unknown open_memstream() function.

FILE *open_memstream(char **ptr, size_t *sizeloc);

Example of usage :

// open the stream
FILE *stream;
char *buf;
size_t len;
stream = open_memstream(&buf, &len);

// write what you want with fprintf() into the stream
fprintf(stream, "Hello");
fprintf(stream, " ");
fprintf(stream, "%s\n", "world");

// close the stream, the buffer is allocated and the size is set !
fclose(stream);
printf ("the result is '%s' (%d characters)\n", buf, len);
free(buf);

If you don't know in advance the length of what you want to append, this is convenient and safer than managing buffers yourself.

Sql connection-string for localhost server

Do You have Internal Connection or External Connection. If you did Internal Connection then try this:

"Data Source=.\SQLEXPRESS;AttachDbFilename="Your PAth .mdf";Integrated Security=True;User Instance=True";

Adding whitespace in Java

There's a few approaches for this:

  1. Create a char array then use Arrays.fill, and finally convert to a String
  2. Iterate through a loop adding a space each time
  3. Use String.format

What is the difference between Amazon SNS and Amazon SQS?

AWS SNS is a publisher subscriber network, where subscribers can subscribe to topics and will receive messages whenever a publisher publishes to that topic.

AWS SQS is a queue service, which stores messages in a queue. SQS cannot deliver any messages, where an external service (lambda, EC2, etc.) is needed to poll SQS and grab messages from SQS.

SNS and SQS can be used together for multiple reasons.

  1. There may be different kinds of subscribers where some need the immediate delivery of messages, where some would require the message to persist, for later usage via polling. See this link.

  2. The "Fanout Pattern." This is for the asynchronous processing of messages. When a message is published to SNS, it can distribute it to multiple SQS queues in parallel. This can be great when loading thumbnails in an application in parallel, when images are being published. See this link.

  3. Persistent storage. When a service that is going to process a message is not reliable. In a case like this, if SNS pushes a notification to a Service, and that service is unavailable, then the notification will be lost. Therefore we can use SQS as a persistent storage and then process it afterwards.

Find and replace Android studio

Use ctrl+R or cmd+R in OSX

Using cURL with a username and password?

You can also just send the user name by writing:

curl -u USERNAME http://server.example

Curl will then ask you for the password, and the password will not be visible on the screen (or if you need to copy/paste the command).

Updating PartialView mvc 4

So, say you have your View with PartialView, which have to be updated by button click:

<div class="target">
    @{ Html.RenderAction("UpdatePoints");}
</div>

<input class="button" value="update" />

There are some ways to do it. For example you may use jQuery:

<script type="text/javascript">
    $(function(){    
        $('.button').on("click", function(){        
            $.post('@Url.Action("PostActionToUpdatePoints", "Home")').always(function(){
                $('.target').load('/Home/UpdatePoints');        
            })        
        });
    });        
</script>

PostActionToUpdatePoints is your Action with [HttpPost] attribute, which you use to update points

If you use logic in your action UpdatePoints() to update points, maybe you forgot to add [HttpPost] attribute to it:

[HttpPost]
public ActionResult UpdatePoints()
{    
    ViewBag.points =  _Repository.Points;
    return PartialView("UpdatePoints");
}

jQuery toggle CSS?

The best option would be to set a class style in CSS like .showMenu and .hideMenu with the various styles inside. Then you can do something like

$("#user_button").addClass("showMenu"); 

Given two directory trees, how can I find out which files differ by content?

To report differences between dirA and dirB, while also updating/syncing.

rsync -auv <dirA> <dirB>

Go Back to Previous Page

You specifically asked for JS solutions, but in the event that someone visits your form with JS disabled a PHP backup is always nice:

when the form loads grab the previous page address via something like $previous = $_SERVER['HTTP_REFERER']; and then set that as a <input type="hidden" value="$previous" /> in your form. When you process your form with the script you can grab that value and stick it in the header("Location:___") or stick the address directly into a link to send them back where they came from

No JS, pretty simple, and you can structure it so that it's only handled if the client doesn't have JS enabled.

Activating Anaconda Environment in VsCode

I found a hacky solution replace your environment variable for the original python file so instead it can just call from the python.exe from your anaconda folder, so when you reference python it will reference anaconda's python.

So your only python path in env var should be like:

"C:\Anaconda3\envs\py34\", or wherever the python executable lives

If you need more details I don't mind explaining. :)

Extract Month and Year From Date in R

This will add a new column to your data.frame with the specified format.

df$Month_Yr <- format(as.Date(df$Date), "%Y-%m")

df
#>   ID       Date Month_Yr
#> 1  1 2004-02-06  2004-02
#> 2  2 2006-03-14  2006-03
#> 3  3 2007-07-16  2007-07

# your data sample
  df <- data.frame( ID=1:3,Date = c("2004-02-06" , "2006-03-14" , "2007-07-16") )

a simple example:

dates <- "2004-02-06"

format(as.Date(dates), "%Y-%m")
> "2004-02"

side note: the data.table approach can be quite faster in case you're working with a big dataset.

library(data.table)
setDT(df)[, Month_Yr := format(as.Date(Date), "%Y-%m") ]

Gradle Build Android Project "Could not resolve all dependencies" error

As Peter says, they won't be in Maven Central

from the Android SDK Manager download the 'Android Support Repository' and a Maven repo of the support libraries will be downloaded to your Android SDK directory (see 'extras' folder)

to deploy the libraries to your local .m2 repository you can use maven-android-sdk-deployer

2017 edit:

you can now reference the Google online M2 repo

repositories {
google()
jcenter()
}

Can I call a base class's virtual function if I'm overriding it?

If you want to call a function of base class from its derived class you can simply call inside the overridden function with mentioning base class name(like Foo::printStuff()).

code goes here

#include <iostream>
using namespace std;

class Foo
{
public:
    int x;

    virtual void printStuff()
    {
         cout<<"Base Foo printStuff called"<<endl;
    }
};

class Bar : public Foo
{
public:
    int y;

    void printStuff()
    {
        cout<<"derived Bar printStuff called"<<endl;
        Foo::printStuff();/////also called the base class method
    }
};

int main()
{
    Bar *b=new Bar;
    b->printStuff();
}

Again you can determine at runtime which function to call using the object of that class(derived or base).But this requires your function at base class must be marked as virtual.

code below

#include <iostream>
using namespace std;

class Foo
{
public:
    int x;

    virtual void printStuff()
    {
         cout<<"Base Foo printStuff called"<<endl;
    }
};

class Bar : public Foo
{
public:
    int y;

    void printStuff()
    {
        cout<<"derived Bar printStuff called"<<endl;
    }
};

int main()
{

    Foo *foo=new Foo;
    foo->printStuff();/////this call the base function
    foo=new Bar;
    foo->printStuff();
}

How do I apply a diff patch on Windows?

I am already using BeyondCompare (commercial) for diffs and merges, and this tool also has the capability to create, view and apply patches.

What does it mean with bug report captured in android tablet?

It's because you have turned on USB debugging in Developer Options. You can create a bug report by holding the power + both volume up and down.

Edit: This is what the forums say:

By pressing Volume up + Volume down + power button, you will feel a vibration after a second or so, that's when the bug reporting initiated.

To disable:

/system/bin/bugmailer.sh must be deleted/renamed.

There should be a folder on your SD card called "bug reports".

Have a look at this thread: http://forum.xda-developers.com/showthread.php?t=2252948

And this one: http://forum.xda-developers.com/showthread.php?t=1405639

How to get response body using HttpURLConnection, when code other than 2xx is returned?

Wrong method was used for errors, here is the working code:

BufferedReader br = null;
if (100 <= conn.getResponseCode() && conn.getResponseCode() <= 399) {
    br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
} else {
    br = new BufferedReader(new InputStreamReader(conn.getErrorStream()));
}

Cannot hide status bar in iOS7

In Info Plist file Add a row for following property

Property Name : View controller-based status bar appearance

Value : NO

Number to String in a formula field

CSTR({number_field}, 0, '')

The second placeholder is for decimals.

The last placeholder is for thousands separator.

What does the JSLint error 'body of a for in should be wrapped in an if statement' mean?

This means that you should filter the properties of evtListeners with the hasOwnProperty method.

What is the difference between a deep copy and a shallow copy?

A shallow copy constructs a new compound object and insert its references into it to the original object.

Unlike shallow copy, deepcopy constructs new compound object and also inserts copies of the original objects of original compound object.

Lets take an example.

import copy
x =[1,[2]]
y=copy.copy(x)
z= copy.deepcopy(x)
print(y is z)

Above code prints FALSE.

Let see how.

Original compound object x=[1,[2]] (called as compound because it has object inside object (Inception))

enter image description here

as you can see in the image, there is a list inside list.

Then we create a shallow copy of it using y = copy.copy(x). What python does here is, it will create a new compound object but objects inside them are pointing to the orignal objects.

enter image description here

In the image it has created a new copy for outer list. but the inner list remains same as the original one.

Now we create deepcopy of it using z = copy.deepcopy(x). what python does here is, it will create new object for outer list as well as inner list. as shown in the image below (red highlighted).

enter image description here

At the end code prints False, as y and z are not same objects.

HTH.

Getting json body in aws Lambda via API gateway

I am using lambda with Zappa; I am sending data with POST in json format:

My code for basic_lambda_pure.py is:

import time
import requests
import json
def my_handler(event, context):
    print("Received event: " + json.dumps(event, indent=2))
    print("Log stream name:", context.log_stream_name)
    print("Log group name:",  context.log_group_name)
    print("Request ID:", context.aws_request_id)
    print("Mem. limits(MB):", context.memory_limit_in_mb)
    # Code will execute quickly, so we add a 1 second intentional delay so you can see that in time remaining value.
    print("Time remaining (MS):", context.get_remaining_time_in_millis())

    if event["httpMethod"] == "GET":
        hub_mode = event["queryStringParameters"]["hub.mode"]
        hub_challenge = event["queryStringParameters"]["hub.challenge"]
        hub_verify_token = event["queryStringParameters"]["hub.verify_token"]
        return {'statusCode': '200', 'body': hub_challenge, 'headers': 'Content-Type': 'application/json'}}

    if event["httpMethod"] == "post":
        token = "xxxx"
    params = {
        "access_token": token
    }
    headers = {
        "Content-Type": "application/json"
    }
        _data = {"recipient": {"id": 1459299024159359}}
        _data.update({"message": {"text": "text"}})
        data = json.dumps(_data)
        r = requests.post("https://graph.facebook.com/v2.9/me/messages",params=params, headers=headers, data=data, timeout=2)
        return {'statusCode': '200', 'body': "ok", 'headers': {'Content-Type': 'application/json'}}

I got the next json response:

{
"resource": "/",
"path": "/",
"httpMethod": "POST",
"headers": {
"Accept": "*/*",
"Accept-Encoding": "deflate, gzip",
"CloudFront-Forwarded-Proto": "https",
"CloudFront-Is-Desktop-Viewer": "true",
"CloudFront-Is-Mobile-Viewer": "false",
"CloudFront-Is-SmartTV-Viewer": "false",
"CloudFront-Is-Tablet-Viewer": "false",
"CloudFront-Viewer-Country": "US",
"Content-Type": "application/json",
"Host": "ox53v9d8ug.execute-api.us-east-1.amazonaws.com",
"Via": "1.1 f1836a6a7245cc3f6e190d259a0d9273.cloudfront.net (CloudFront)",
"X-Amz-Cf-Id": "LVcBZU-YqklHty7Ii3NRFOqVXJJEr7xXQdxAtFP46tMewFpJsQlD2Q==",
"X-Amzn-Trace-Id": "Root=1-59ec25c6-1018575e4483a16666d6f5c5",
"X-Forwarded-For": "69.171.225.87, 52.46.17.84",
"X-Forwarded-Port": "443",
"X-Forwarded-Proto": "https",
"X-Hub-Signature": "sha1=10504e2878e56ea6776dfbeae807de263772e9f2"
},
"queryStringParameters": null,
"pathParameters": null,
"stageVariables": null,
"requestContext": {
"path": "/dev",
"accountId": "001513791584",
"resourceId": "i6d2tyihx7",
"stage": "dev",
"requestId": "d58c5804-b6e5-11e7-8761-a9efcf8a8121",
"identity": {
"cognitoIdentityPoolId": null,
"accountId": null,
"cognitoIdentityId": null,
"caller": null,
"apiKey": "",
"sourceIp": "69.171.225.87",
"accessKey": null,
"cognitoAuthenticationType": null,
"cognitoAuthenticationProvider": null,
"userArn": null,
"userAgent": null,
"user": null
},
"resourcePath": "/",
"httpMethod": "POST",
"apiId": "ox53v9d8ug"
},
"body": "eyJvYmplY3QiOiJwYWdlIiwiZW50cnkiOlt7ImlkIjoiMTA3OTk2NDk2NTUxMDM1IiwidGltZSI6MTUwODY0ODM5MDE5NCwibWVzc2FnaW5nIjpbeyJzZW5kZXIiOnsiaWQiOiIxNDAzMDY4MDI5ODExODY1In0sInJlY2lwaWVudCI6eyJpZCI6IjEwNzk5NjQ5NjU1MTAzNSJ9LCJ0aW1lc3RhbXAiOjE1MDg2NDgzODk1NTUsIm1lc3NhZ2UiOnsibWlkIjoibWlkLiRjQUFBNHo5RmFDckJsYzdqVHMxZlFuT1daNXFaQyIsInNlcSI6MTY0MDAsInRleHQiOiJob2xhIn19XX1dfQ==",
"isBase64Encoded": true
}

my data was on body key, but is code64 encoded, How can I know this? I saw the key isBase64Encoded

I copy the value for body key and decode with This tool and "eureka", I get the values.

I hope this help you. :)

password for postgres

Set the default password in the .pgpass file. If the server does not save the password, it is because it is not set in the .pgpass file, or the permissions are open and the file is therefore ignored.

Read more about the password file here.

Also, be sure to check the permissions: on *nix systems the permissions on .pgpass must disallow any access to world or group; achieve this by the command chmod 0600 ~/.pgpass. If the permissions are less strict than this, the file will be ignored.

Have you tried logging-in using PGAdmin? You can save the password there, and modify the pgpass file.

How to use the ConfigurationManager.AppSettings

ConfigurationManager.AppSettings is actually a property, so you need to use square brackets.

Overall, here's what you need to do:

SqlConnection con= new SqlConnection(ConfigurationManager.AppSettings["ConnectionString"]);

The problem is that you tried to set con to a string, which is not correct. You have to either pass it to the constructor or set con.ConnectionString property.

Can I fade in a background image (CSS: background-image) with jQuery?

i have been searching for ages and finally i put everything together to find my solution. Folks say, you cannot fade-in/-out the background-image- id of the html-background. Thats definitely wrong as you can figure out by implementing the below mentioned demo

CSS:

html, body

height: 100%;   /* ges Hoehe der Seite -> weitere Hoehenangaben werden relativ hierzu ausgewertet */
overflow: hidden;   /*  hide scrollbars */
opacity: 1.0;
-webkit-transition: background 1.5s linear;
-moz-transition: background 1.5s linear;
-o-transition: background 1.5s linear;
-ms-transition: background 1.5s linear;
transition: background 1.5s linear;

Changing body's background-image can now easily be done using JavaScript:

switch (dummy)

case 1:

$(document.body).css({"background-image": "url("+URL_of_pic_One+")"});
waitAWhile();

case 2:
$(document.body).css({"background-image": "url("+URL_of_pic_Two+")"});
waitAWhile();

How to read value of a registry key c#

Change:

using (RegistryKey key = Registry.LocalMachine.OpenSubKey("Software\\Wow6432Node\\MySQL AB\\MySQL Connector\\Net"))

To:

 using (RegistryKey key = Registry.LocalMachine.OpenSubKey("Software\Wow6432Node\MySQL AB\MySQL Connector\Net"))

Send inline image in email

An even more minimalistic example:

var linkedResource = new LinkedResource(@"C:\Image.jpg", MediaTypeNames.Image.Jpeg);

// My mail provider would not accept an email with only an image, adding hello so that the content looks less suspicious.
var htmlBody = $"hello<img src=\"cid:{linkedResource.ContentId}\"/>";
var alternateView = AlternateView.CreateAlternateViewFromString(htmlBody, null, MediaTypeNames.Text.Html);
alternateView.LinkedResources.Add(linkedResource);

var mailMessage = new MailMessage
{
    From = new MailAddress("[email protected]"),
    To = { "[email protected]" },
    Subject = "yourSubject",
    AlternateViews = { alternateView }
};

var smtpClient = new SmtpClient();
smtpClient.Send(mailMessage);

matplotlib get ylim values

I put above-mentioned methods together using ax instead of plt

import numpy as np
import matplotlib.pyplot as plt

x = range(100)
y = x

fig, ax = plt.subplots(1, 1, figsize=(7.2, 7.2))
ax.plot(x, y);

# method 1
print(ax.get_xlim())
print(ax.get_xlim())
# method 2
print(ax.axis())

enter image description here

C# string reference type?

As others have stated, the String type in .NET is immutable and it's reference is passed by value.

In the original code, as soon as this line executes:

test = "after passing";

then test is no longer referring to the original object. We've created a new String object and assigned test to reference that object on the managed heap.

I feel that many people get tripped up here since there's no visible formal constructor to remind them. In this case, it's happening behind the scenes since the String type has language support in how it is constructed.

Hence, this is why the change to test is not visible outside the scope of the TestI(string) method - we've passed the reference by value and now that value has changed! But if the String reference were passed by reference, then when the reference changed we will see it outside the scope of the TestI(string) method.

Either the ref or out keyword are needed in this case. I feel the out keyword might be slightly better suited for this particular situation.

class Program
{
    static void Main(string[] args)
    {
        string test = "before passing";
        Console.WriteLine(test);
        TestI(out test);
        Console.WriteLine(test);
        Console.ReadLine();
    }

    public static void TestI(out string test)
    {
        test = "after passing";
    }
}

Efficiency of Java "Double Brace Initialization"?

Taking the following test class:

public class Test {
  public void test() {
    Set<String> flavors = new HashSet<String>() {{
        add("vanilla");
        add("strawberry");
        add("chocolate");
        add("butter pecan");
    }};
  }
}

and then decompiling the class file, I see:

public class Test {
  public void test() {
    java.util.Set flavors = new HashSet() {

      final Test this$0;

      {
        this$0 = Test.this;
        super();
        add("vanilla");
        add("strawberry");
        add("chocolate");
        add("butter pecan");
      }
    };
  }
}

This doesn't look terribly inefficient to me. If I were worried about performance for something like this, I'd profile it. And your question #2 is answered by the above code: You're inside an implicit constructor (and instance initializer) for your inner class, so "this" refers to this inner class.

Yes, this syntax is obscure, but a comment can clarify obscure syntax usage. To clarify the syntax, most people are familiar with a static initializer block (JLS 8.7 Static Initializers):

public class Sample1 {
    private static final String someVar;
    static {
        String temp = null;
        ..... // block of code setting temp
        someVar = temp;
    }
}

You can also use a similar syntax (without the word "static") for constructor usage (JLS 8.6 Instance Initializers), although I have never seen this used in production code. This is much less commonly known.

public class Sample2 {
    private final String someVar;

    // This is an instance initializer
    {
        String temp = null;
        ..... // block of code setting temp
        someVar = temp;
    }
}

If you don't have a default constructor, then the block of code between { and } is turned into a constructor by the compiler. With this in mind, unravel the double brace code:

public void test() {
  Set<String> flavors = new HashSet<String>() {
      {
        add("vanilla");
        add("strawberry");
        add("chocolate");
        add("butter pecan");
      }
  };
}

The block of code between the inner-most braces is turned into a constructor by the compiler. The outer-most braces delimit the anonymous inner class. To take this the final step of making everything non-anonymous:

public void test() {
  Set<String> flavors = new MyHashSet();
}

class MyHashSet extends HashSet<String>() {
    public MyHashSet() {
        add("vanilla");
        add("strawberry");
        add("chocolate");
        add("butter pecan");
    }
}

For initialization purposes, I'd say there is no overhead whatsoever (or so small that it can be neglected). However, every use of flavors will go not against HashSet but instead against MyHashSet. There is probably a small (and quite possibly negligible) overhead to this. But again, before I worried about it, I would profile it.

Again, to your question #2, the above code is the logical and explicit equivalent of double brace initialization, and it makes it obvious where "this" refers: To the inner class that extends HashSet.

If you have questions about the details of instance initializers, check out the details in the JLS documentation.

What are Aggregates and PODs and how/why are they special?

POD in C++11 was basically split into two different axes here: triviality and layout. Triviality is about the relationship between an object's conceptual value and the bits of data within its storage. Layout is about... well, the layout of an object's subobjects. Only class types have layout, while all types have triviality relationships.

So here is what the triviality axis is about:

  1. Non-trivially copyable: The value of objects of such types may be more than just the binary data that are stored directly within the object.

    For example, unique_ptr<T> stores a T*; that is the totality of the binary data within the object. But that's not the totality of the value of a unique_ptr<T>. A unique_ptr<T> stores either a nullptr or a pointer to an object whose lifetime is managed by the unique_ptr<T> instance. That management is part of the value of a unique_ptr<T>. And that value is not part of the binary data of the object; it is created by the various member functions of that object.

    For example, to assign nullptr to a unique_ptr<T> is to do more than just change the bits stored in the object. Such an assignment must destroy any object managed by the unique_ptr. To manipulate the internal storage of a unique_ptr without going through its member functions would damage this mechanism, to change its internal T* without destroying the object it currently manages, would violate the conceptual value that the object possesses.

  2. Trivially copyable: The value of such objects are exactly and only the contents of their binary storage. This is what makes it reasonable to allow copying that binary storage to be equivalent to copying the object itself.

    The specific rules that define trivial copyability (trivial destructor, trivial/deleted copy/move constructors/assignment) are what is required for a type to be binary-value-only. An object's destructor can participate in defining the "value" of an object, as in the case with unique_ptr. If that destructor is trivial, then it doesn't participate in defining the object's value.

    Specialized copy/move operations also can participate in an object's value. unique_ptr's move constructor modifies the source of the move operation by null-ing it out. This is what ensures that the value of a unique_ptr is unique. Trivial copy/move operations mean that such object value shenanigans are not being played, so the object's value can only be the binary data it stores.

  3. Trivial: This object is considered to have a functional value for any bits that it stores. Trivially copyable defines the meaning of the data store of an object as being just that data. But such types can still control how data gets there (to some extent). Such a type can have default member initializers and/or a default constructor that ensures that a particular member always has a particular value. And thus, the conceptual value of the object can be restricted to a subset of the binary data that it could store.

    Performing default initialization on a type that has a trivial default constructor will leave that object with completely uninitialized values. As such, a type with a trivial default constructor is logically valid with any binary data in its data storage.

The layout axis is really quite simple. Compilers are given a lot of leeway in deciding how the subobjects of a class are stored within the class's storage. However, there are some cases where this leeway is not necessary, and having more rigid ordering guarantees is useful.

Such types are standard layout types. And the C++ standard doesn't even really do much with saying what that layout is specifically. It basically says three things about standard layout types:

  1. The first subobject is at the same address as the object itself.

  2. You can use offsetof to get a byte offset from the outer object to one of its member subobjects.

  3. unions get to play some games with accessing subobjects through an inactive member of a union if the active member is (at least partially) using the same layout as the inactive one being accessed.

Compilers generally permit standard layout objects to map to struct types with the same members in C. But there is no statement of that in the C++ standard; that's just what compilers feel like doing.

POD is basically a useless term at this point. It is just the intersection of trivial copyability (the value is only its binary data) and standard layout (the order of its subobjects is more well-defined). One can infer from such things that the type is C-like and could map to similar C objects. But the standard has no statements to that effect.


can you please elaborate following rules:

I'll try:

a) standard-layout classes must have all non-static data members with the same access control

That's simple: all non-static data members must all be public, private, or protected. You can't have some public and some private.

The reasoning for them goes to the reasoning for having a distinction between "standard layout" and "not standard layout" at all. Namely, to give the compiler the freedom to choose how to put things into memory. It's not just about vtable pointers.

Back when they standardized C++ in 98, they had to basically predict how people would implement it. While they had quite a bit of implementation experience with various flavors of C++, they weren't certain about things. So they decided to be cautious: give the compilers as much freedom as possible.

That's why the definition of POD in C++98 is so strict. It gave C++ compilers great latitude on member layout for most classes. Basically, POD types were intended to be special cases, something you specifically wrote for a reason.

When C++11 was being worked on, they had a lot more experience with compilers. And they realized that... C++ compiler writers are really lazy. They had all this freedom, but they didn't do anything with it.

The rules of standard layout are more or less codifying common practice: most compilers didn't really have to change much if anything at all to implement them (outside of maybe some stuff for the corresponding type traits).

Now, when it came to public/private, things are different. The freedom to reorder which members are public vs. private actually can matter to the compiler, particularly in debugging builds. And since the point of standard layout is that there is compatibility with other languages, you can't have the layout be different in debug vs. release.

Then there's the fact that it doesn't really hurt the user. If you're making an encapsulated class, odds are good that all of your data members will be private anyway. You generally don't expose public data members on fully encapsulated types. So this would only be a problem for those few users who do want to do that, who want that division.

So it's no big loss.

b) only one class in the whole inheritance tree can have non-static data members,

The reason for this one comes back to why they standardized standard layout again: common practice.

There's no common practice when it comes to having two members of an inheritance tree that actually store things. Some put the base class before the derived, others do it the other way. Which way do you order the members if they come from two base classes? And so on. Compilers diverge greatly on these questions.

Also, thanks to the zero/one/infinity rule, once you say you can have two classes with members, you can say as many as you want. This requires adding a lot of layout rules for how to handle this. You have to say how multiple inheritance works, which classes put their data before other classes, etc. That's a lot of rules, for very little material gain.

You can't make everything that doesn't have virtual functions and a default constructor standard layout.

and the first non-static data member cannot be of a base class type (this could break aliasing rules).

I can't really speak to this one. I'm not educated enough in C++'s aliasing rules to really understand it. But it has something to do with the fact that the base member will share the same address as the base class itself. That is:

struct Base {};
struct Derived : Base { Base b; };

Derived d;
static_cast<Base*>(&d) == &d.b;

And that's probably against C++'s aliasing rules. In some way.

However, consider this: how useful could having the ability to do this ever actually be? Since only one class can have non-static data members, then Derived must be that class (since it has a Base as a member). So Base must be empty (of data). And if Base is empty, as well as a base class... why have a data member of it at all?

Since Base is empty, it has no state. So any non-static member functions will do what they do based on their parameters, not their this pointer.

So again: no big loss.

Apache HttpClient Interim Error: NoHttpResponseException

I have faced same issue, I resolved by adding "connection: close" as extention,

Step 1: create a new class ConnectionCloseExtension

import com.github.tomakehurst.wiremock.common.FileSource;
import com.github.tomakehurst.wiremock.extension.Parameters;
import com.github.tomakehurst.wiremock.extension.ResponseTransformer;
import com.github.tomakehurst.wiremock.http.HttpHeader;
import com.github.tomakehurst.wiremock.http.HttpHeaders;
import com.github.tomakehurst.wiremock.http.Request;
import com.github.tomakehurst.wiremock.http.Response;

public class ConnectionCloseExtension extends ResponseTransformer {
  @Override
  public Response transform(Request request, Response response, FileSource files, Parameters parameters) {
    return Response.Builder
        .like(response)
        .headers(HttpHeaders.copyOf(response.getHeaders())
            .plus(new HttpHeader("Connection", "Close")))
        .build();
  }

  @Override
  public String getName() {
    return "ConnectionCloseExtension";
  }
}

Step 2: set extension class in wireMockServer like below,

final WireMockServer wireMockServer = new WireMockServer(options()
                .extensions(ConnectionCloseExtension.class)
                .port(httpPort));

Playing m3u8 Files with HTML Video Tag

In normally html5 video player will support mp4, WebM, 3gp and OGV format directly.

    <video controls>
      <source src=http://techslides.com/demos/sample-videos/small.webm type=video/webm>
      <source src=http://techslides.com/demos/sample-videos/small.ogv type=video/ogg>
      <source src=http://techslides.com/demos/sample-videos/small.mp4 type=video/mp4>
      <source src=http://techslides.com/demos/sample-videos/small.3gp type=video/3gp>
    </video>

We can add an external HLS js script in web application.

    <!DOCTYPE html>
    <html>
    <head>
    <meta charset=utf-8 />
    <title>Your title</title>
      
    
      <link href="https://unpkg.com/video.js/dist/video-js.css" rel="stylesheet">
      <script src="https://unpkg.com/video.js/dist/video.js"></script>
      <script src="https://unpkg.com/videojs-contrib-hls/dist/videojs-contrib-hls.js"></script>
       
    </head>
    <body>
      <video id="my_video_1" class="video-js vjs-fluid vjs-default-skin" controls preload="auto"
      data-setup='{}'>
        <source src="https://cdn3.wowza.com/1/ejBGVnFIOW9yNlZv/cithRSsv/hls/live/playlist.m3u8" type="application/x-mpegURL">
      </video>
      
    <script>
    var player = videojs('my_video_1');
    player.play();
    </script>
      
    </body>
    </html>

Using HTML and Local Images Within UIWebView

try use base64 image string.

NSData* data = UIImageJPEGRepresentation(image, 1.0f);

NSString *strEncoded = [data base64Encoding];   

<img src='data:image/png;base64,%@ '/>,strEncoded

How to exclude *AutoConfiguration classes in Spring Boot JUnit tests?

If the issue is that your SpringBootApplication/Configuration you are bringing in is component scanning the package your test configurations are in, you can actually remove the @Configuration annotation from the test configurations and you can still use them in the @SpringBootTest annotations. For example, if you have a class Application that is your main configuration and a class TestConfiguration that is a configuration for certain, but not all tests, you can set up your classes as follows:

@Import(Application.class) //or the specific configurations you want
//(Optional) Other Annotations that will not trigger an autowire
public class TestConfiguration {
    //your custom test configuration
}

And then you can configure your tests in one of two ways:

  1. With the regular configuration:

    @SpringBootTest(classes = {Application.class}) //won't component scan your configuration because it doesn't have an autowire-able annotation
    //Other annotations here
    public class TestThatUsesNormalApplication {
        //my test code
    }
    
  2. With the test custom test configuration:

    @SpringBootTest(classes = {TestConfiguration.class}) //this still works!
    //Other annotations here
    public class TestThatUsesCustomTestConfiguration {
        //my test code
    }
    

:not(:empty) CSS selector is not working?

Since placeholder disappear on input, you can use:

input:placeholder-shown{
    //rules for not empty input
}

How to query a CLOB column in Oracle

This works

select DBMS_LOB.substr(myColumn, 3000) from myTable

SQL Insert into table only if record doesn't exist

This might be a simple solution to achieve this:

INSERT INTO funds (ID, date, price)
SELECT 23, DATE('2013-02-12'), 22.5
  FROM dual
 WHERE NOT EXISTS (SELECT 1 
                     FROM funds 
                    WHERE ID = 23
                      AND date = DATE('2013-02-12'));

p.s. alternatively (if ID a primary key):

 INSERT INTO funds (ID, date, price)
    VALUES (23, DATE('2013-02-12'), 22.5)
        ON DUPLICATE KEY UPDATE ID = 23; -- or whatever you need

see this Fiddle.

How to join two sets in one line without using "|"

Suppose you have 2 lists

 A = [1,2,3,4]
 B = [3,4,5,6]

so you can find A Union B as follow

 union = set(A).union(set(B))

also if you want to find intersection and non-intersection you do that as follow

 intersection = set(A).intersection(set(B))
 non_intersection = union - intersection

How to write to a file, using the logging Python module?

Taken from the "logging cookbook":

# create logger with 'spam_application'
logger = logging.getLogger('spam_application')
logger.setLevel(logging.DEBUG)
# create file handler which logs even debug messages
fh = logging.FileHandler('spam.log')
fh.setLevel(logging.DEBUG)
logger.addHandler(fh)

And you're good to go.

P.S. Make sure to read the logging HOWTO as well.

Twitter Bootstrap add active class to li

This works fine for me. It marks both simple nav elements and dropdown nav elements as active.

$(document).ready(function () {
   var url = window.location;

   $('ul.nav a[href="' + this.location.pathname + '"]').parent().addClass('active');

   $('ul.nav a').filter(function() {
      return this.href == url;
   }).parent().parent().parent().addClass('active');
});

Passing this.location.pathname to $('ul.nav a[href="'...'"]') marks also simple nav elements. Passing url did'nt work for me.

Marker content (infoWindow) Google Maps

We've solved this, although we didn't think having the addListener outside of the for would make any difference, it seems to. Here's the answer:

Create a new function with your information for the infoWindow in it:

function addInfoWindow(marker, message) {

            var infoWindow = new google.maps.InfoWindow({
                content: message
            });

            google.maps.event.addListener(marker, 'click', function () {
                infoWindow.open(map, marker);
            });
        }

Then call the function with the array ID and the marker you want to create:

addInfoWindow(marker, hotels[i][3]);

Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

This is a problem if you are running out of disk space. Solution is to free some space from the HDD.

Please read more to have the explanation :

If you are running MySQL at LINUX check the free space of HDD with the command disk free :

 df 

if you are getting something like that :

Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda2              5162828   4902260         0 100% /
udev                    156676        84    156592   1% /dev
/dev/sda3              3107124     70844   2878444   3% /home

Then this is the problem and now you have the solution!

Since mysql.sock wants to be created at the mysql folder which is almost always under the root folder could not achieve it because lack of space.

If you are periodicaly give the ls command under the mysql directory (at openSUSE 11.1 is at /var/lib/mysql) you will get something like :

hostname:/var/lib/mysql #
.protected  IT     files        ibdata1             mysqld.log  systemtemp
.tmp        NEWS   greekDB      mysql               mysqld.pid  test
ARXEIO      TEMP1  ib_logfile0  mysql.sock          polis
DATING      deisi  ib_logfile1  mysql_upgrade_info  restore

The mysql.sock file appearing and disappearing often (you must to try allot with the ls to hit a instance with the mysql.sock file on folder).

This caused by not enough disk space.

I hope that i will help some people!!!! Thanks!

How can I create an object based on an interface file definition in TypeScript?

If you are creating the "modal" variable elsewhere, and want to tell TypeScript it will all be done, you would use:

declare const modal: IModal;

If you want to create a variable that will actually be an instance of IModal in TypeScript you will need to define it fully.

const modal: IModal = {
    content: '',
    form: '',
    href: '',
    $form: null,
    $message: null,
    $modal: null,
    $submits: null
};

Or lie, with a type assertion, but you'll lost type safety as you will now get undefined in unexpected places, and possibly runtime errors, when accessing modal.content and so on (properties that the contract says will be there).

const modal = {} as IModal;

Example Class

class Modal implements IModal {
    content: string;
    form: string;
    href: string;
    $form: JQuery;
    $message: JQuery;
    $modal: JQuery;
    $submits: JQuery;
}

const modal = new Modal();

You may think "hey that's really a duplication of the interface" - and you are correct. If the Modal class is the only implementation of the IModal interface you may want to delete the interface altogether and use...

const modal: Modal = new Modal();

Rather than

const modal: IModal = new Modal();

EditorFor() and html properties

I solved this by creating an EditorTemplate named String.ascx in my /Views/Shared/EditorTemplates folder:

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<string>" %>
<% int size = 10;
   int maxLength = 100;
   if (ViewData["size"] != null)
   {
       size = (int)ViewData["size"];
   }
   if (ViewData["maxLength"] != null)
   {
       maxLength = (int)ViewData["maxLength"];
   }
%>
<%= Html.TextBox("", Model, new { Size=size, MaxLength=maxLength }) %>

In my view, I use

<%= Html.EditorFor(model => model.SomeStringToBeEdited, new { size = 15, maxLength = 10 }) %>

Works like a charm for me!

How to enable Ad Hoc Distributed Queries

If ad hoc updates to system catalog is "not supported", or if you get a "Msg 5808" then you will need to configure with override like this:

EXEC sp_configure 'show advanced options', 1
RECONFIGURE with override
GO
EXEC sp_configure 'ad hoc distributed queries', 1
RECONFIGURE with override
GO

Find package name for Android apps to use Intent to launch Market app from web

It depends where exactly you want to get the information from. You have a bunch of options:

  • If you have a copy of the .apk, it's just a case of opening it as a zip file and looking at the AndroidManifest.xml file. The top level <manifest> element will have a package attribute.
  • If you have the app installed on a device and can connect using adb, you can launch adb shell and execute pm list packages -f, which shows the package name for each installed apk.
  • If you just want to manually find a couple of package names, you can search for the app on http://www.cyrket.com/m/android/, and the package name is shown in the URL
  • You can also do it progmatically from an Android app using the PackageManager

Once you've got the package name, you simply link to market://search?q=pname:<package_name> or http://market.android.com/search?q=pname:<package_name>. Both will open the market on an Android device; the latter obviously has the potential to work on other hardware as well (it doesn't at the minute).

How to Install Sublime Text 3 using Homebrew

An update

Turns out now brew cask install sublime-text installs the most up to date version (e.g. 3) by default and brew cask is now part of the standard brew-installation.

How to know what the 'errno' means?

It means:

File or Directory not found.

How can I backup a Docker-container with its data-volumes?

If you only need to backup mounted volumes you can just copy folders from your Dockerhost.

Note: If you are on Ubuntu, Dockerhost is your local machine. If you are on Mac, Dockerhost is your virtual machine.

On Ubuntu

You can find all folders with volumes here: /var/lib/docker/volumes/ so you can copy them and archive wherever you want.

On MAC

It's not so easy as on Ubuntu. You need to copy files from VM.

Here is a script of how to copy all folders with volumes from virtual machine (where Docker server is running) to your local machine. We assume that your docker-machine VM named default.

docker-machine ssh default sudo cp -v -R /var/lib/docker/volumes/ /home/docker/volumes

docker-machine ssh default sudo chmod -R 777 /home/docker/volumes

docker-machine scp -R default:/home/docker/volumes ./backup_volumes

docker-machine ssh default sudo rm -r /home/docker/volumes

It is going to create a folder ./backup_volumes in your current directory and copy all volumes to this folder.

Here is a script of how to copy all saved volumes from your local directory (./backup_volumes) to Dockerhost machine

docker-machine scp -r ./backup_volumes default:/home/docker

docker-machine ssh default sudo mv -f /home/docker/backup_volumes /home/docker/volumes

docker-machine ssh default sudo chmod -R 777 /home/docker/volumes

docker-machine ssh default sudo cp -v -R /home/docker/volumes /var/lib/docker/

docker-machine ssh default sudo rm -r /home/docker/volumes

Now you can check if it works by:

docker volume ls

Overwriting my local branch with remote branch

git reset --hard

This is to revert all your local changes to the origin head

Java - Best way to print 2D array?

Two-liner with new line:

for(int[] x: matrix)
            System.out.println(Arrays.toString(x));

One liner without new line:

System.out.println(Arrays.deepToString(matrix));

how to get the first and last days of a given month

Basically:

$lastDate = date("Y-m-t", strtotime($query_d));

Date t parameter return days number in current month.

Side-by-side plots with ggplot2

You can use the following multiplot function from Winston Chang's R cookbook

multiplot(plot1, plot2, cols=2)

multiplot <- function(..., plotlist=NULL, cols) {
    require(grid)

    # Make a list from the ... arguments and plotlist
    plots <- c(list(...), plotlist)

    numPlots = length(plots)

    # Make the panel
    plotCols = cols                          # Number of columns of plots
    plotRows = ceiling(numPlots/plotCols) # Number of rows needed, calculated from # of cols

    # Set up the page
    grid.newpage()
    pushViewport(viewport(layout = grid.layout(plotRows, plotCols)))
    vplayout <- function(x, y)
        viewport(layout.pos.row = x, layout.pos.col = y)

    # Make each plot, in the correct location
    for (i in 1:numPlots) {
        curRow = ceiling(i/plotCols)
        curCol = (i-1) %% plotCols + 1
        print(plots[[i]], vp = vplayout(curRow, curCol ))
    }

}

Is it possible to use jQuery .on and hover?

jQuery hover function gives mouseover and mouseout functionality.

$(selector).hover(inFunction,outFunction);

$(".item-image").hover(function () {
    // mouseover event codes...
}, function () {
    // mouseout event codes...
});

Source: http://www.w3schools.com/jquery/event_hover.asp

How do I get the SelectedItem or SelectedIndex of ListView in vb.net?

ListView.FocusedItem.Index 

or you can use foreach loop like this

int index= -1;
foreach (ListViewItem itm in listView1.SelectedItems)
{
    if (itm.Selected)
    {
        index= itm.Index;
    }
}

Paste a multi-line Java String in Eclipse

You can use this Eclipse Plugin: http://marketplace.eclipse.org/node/491839#.UIlr8ZDwCUm This is a multi-line string editor popup. Place your caret in a string literal press ctrl-shift-alt-m and paste your text.

Getting multiple values with scanf()

Just to add, we can use array as well:

int i, array[4];
printf("Enter Four Ints: ");
for(i=0; i<4; i++) {
    scanf("%d", &array[i]);
}

How can I set an SQL Server connection string?

You can use either Windows authentication, if your server is in the domain, or SQL Server authentication. Sa is a system administrator, the root account for SQL Server authentication. But it is a bad practice to use if for connecting to your clients.

You should create your own accounts, and use them to connect to your SQL Server instance. In each connection you set account login, its password and the default database, you want to connect to.

What is sr-only in Bootstrap 3?

The .sr-only class hides an element to all devices except screen readers:

Skip to main content Combine .sr-only with .sr-only-focusable to show the element again when it is focused

.sr-only {
border: 0 !important;
clip: rect(1px, 1px, 1px, 1px) !important; /* 1 */
-webkit-clip-path: inset(50%) !important;
    clip-path: inset(50%) !important;  /* 2 */
height: 1px !important;
margin: -1px !important;
overflow: hidden !important;
padding: 0 !important;
position: absolute !important;
width: 1px !important;
white-space: nowrap !important;            /* 3 */

}

How can I one hot encode in Python?

Try this:

!pip install category_encoders
import category_encoders as ce

categorical_columns = [...the list of names of the columns you want to one-hot-encode ...]
encoder = ce.OneHotEncoder(cols=categorical_columns, use_cat_names=True)
df_train_encoded = encoder.fit_transform(df_train_small)

df_encoded.head()

The resulting dataframe df_train_encoded is the same as the original, but the categorical features are now replaced with their one-hot-encoded versions.

More information on category_encoders here.

What is the purpose of using WHERE 1=1 in SQL statements?

The 1=1 is ignored by always all rdbms. There is no tradeoff executing a query with WHERE 1=1.

Building dynamic WHERE conditions, like ORM frameworks or other do very often, it is easier to append the real where conditions because you avoid checking for prepending an AND to the current condition.

stmt += "WHERE 1=1";
if (v != null) {
   stmt += (" AND col = " + v.ToString());
}

This is how it looks like without 1=1.

var firstCondition = true;
...
if (v != null) {
   if (!firstCondition) {
      stmt += " AND ";
   }
   else {
       stmt += " WHERE ";
       firstCondition = false;
   }
   stmt += "col = " + v.ToString());
}

What is token-based authentication?

I think it's well explained here -- quoting just the key sentences of the long article:

The general concept behind a token-based authentication system is simple. Allow users to enter their username and password in order to obtain a token which allows them to fetch a specific resource - without using their username and password. Once their token has been obtained, the user can offer the token - which offers access to a specific resource for a time period - to the remote site.

In other words: add one level of indirection for authentication -- instead of having to authenticate with username and password for each protected resource, the user authenticates that way once (within a session of limited duration), obtains a time-limited token in return, and uses that token for further authentication during the session.

Advantages are many -- e.g., the user could pass the token, once they've obtained it, on to some other automated system which they're willing to trust for a limited time and a limited set of resources, but would not be willing to trust with their username and password (i.e., with every resource they're allowed to access, forevermore or at least until they change their password).

If anything is still unclear, please edit your question to clarify WHAT isn't 100% clear to you, and I'm sure we can help you further.

How to dockerize maven project? and how many ways to accomplish it?

As a rule of thumb, you should build a fat JAR using Maven (a JAR that contains both your code and all dependencies).

Then you can write a Dockerfile that matches your requirements (if you can build a fat JAR you would only need a base os, like CentOS, and the JVM).

This is what I use for a Scala app (which is Java-based).

FROM centos:centos7

# Prerequisites.

RUN yum -y update
RUN yum -y install wget tar

# Oracle Java 7

WORKDIR /opt

RUN wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/7u71-b14/server-jre-7u71-linux-x64.tar.gz
RUN tar xzf server-jre-7u71-linux-x64.tar.gz
RUN rm -rf server-jre-7u71-linux-x64.tar.gz
RUN alternatives --install /usr/bin/java java /opt/jdk1.7.0_71/bin/java 1

# App

USER daemon

# This copies to local fat jar inside the image
ADD /local/path/to/packaged/app/appname.jar /app/appname.jar

# What to run when the container starts
ENTRYPOINT [ "java", "-jar", "/app/appname.jar" ]

# Ports used by the app
EXPOSE 5000

This creates a CentOS-based image with Java7. When started, it will execute your app jar.

The best way to deploy it is via the Docker Registry, it's like a Github for Docker images.

You can build an image like this:

# current dir must contain the Dockerfile
docker build -t username/projectname:tagname .

You can then push an image in this way:

docker push username/projectname # this pushes all tags

Once the image is on the Docker Registry, you can pull it from anywhere in the world and run it.

See Docker User Guide for more informations.

Something to keep in mind:

You could also pull your repository inside an image and build the jar as part of the container execution, but it's not a good approach, as the code could change and you might end up using a different version of the app without notice.

Building a fat jar removes this issue.

Iterate two Lists or Arrays with one ForEach statement in C#

I understand/hope that the lists have the same length: No, your only bet is going with a plain old standard for loop.

How do you modify a CSS style in the code behind file for divs in ASP.NET?

Another way to do it:

testSpace.Style.Add("display", "none");

or

testSpace.Style["background-image"] = "url(images/foo.png)";

in vb.net you can do it this way:

testSpace.Style.Item("display") = "none"

Serializing and submitting a form with jQuery and PHP

The problem can be PHP configuration:

Please check the setting max_input_vars in the php.ini file.

Try to increase the value of this setting to 5000 as example.

max_input_vars = 5000

Then restart your web-server and try.

WCF Error - Could not find default endpoint element that references contract 'UserService.UserService'

You can also set these values programatically in the class library, this will avoid unnecessary movement of the config files across the library. The example code for simple BasciHttpBinding is -

BasicHttpBinding basicHttpbinding = new BasicHttpBinding(BasicHttpSecurityMode.None);
basicHttpbinding.Name = "BasicHttpBinding_YourName";
basicHttpbinding.Security.Transport.ClientCredentialType = HttpClientCredentialType.None;
basicHttpbinding.Security.Message.ClientCredentialType = BasicHttpMessageCredentialType.UserName;

EndpointAddress endpointAddress = new EndpointAddress("http://<Your machine>/Service1/Service1.svc");
Service1Client proxyClient = new Service1Client(basicHttpbinding,endpointAddress);

Access event to call preventdefault from custom function originating from onclick attribute of tag

You can access the event from onclick like this:

<button onclick="yourFunc(event);">go</button>

and at your javascript function, my advice is adding that first line statement as:

function yourFunc(e) {
    e = e ? e : event;
}

then use everywhere e as event variable

Python 'If not' syntax

Yes, if bar is not None is more explicit, and thus better, assuming it is indeed what you want. That's not always the case, there are subtle differences: if not bar: will execute if bar is any kind of zero or empty container, or False. Many people do use not bar where they really do mean bar is not None.

Using the star sign in grep

The "star sign" is only meaningful if there is something in front of it. If there isn't the tool (grep in this case) may just treat it as an error. For example:

'*xyz'    is meaningless
'a*xyz'   means zero or more occurrences of 'a' followed by xyz

how to use substr() function in jquery?

If you want to extract from a tag then

$('.dep_buttons').text().substr(0,25)

With the mouseover event,

$(this).text($(this).text().substr(0, 25));

The above will extract the text of a tag, then extract again assign it back.

Reverse a string in Python

How about:

>>> 'hello world'[::-1]
'dlrow olleh'

This is extended slice syntax. It works by doing [begin:end:step] - by leaving begin and end off and specifying a step of -1, it reverses a string.

$("#form1").validate is not a function

If you had a link I could look to see what the issue is but here are a couple questions and things to check:

  • Is the ID for your form named "form" in the HTML?
  • Check to see if messages are required, maybe there is some imbalance in parameters
  • You should also add the 'type="text/javascript"' attributes where you are getting jQuery from Google

Also, if you're going to use the Google CDN for getting jQuery you may as well use Microsoft's CDN for getting your validation file. Any of these URLs will work:

Difference between Spring MVC and Spring Boot

Spring MVC and Spring Boot are exist for the different purpose. So, it is not wise to compare each other as the contenders.

What is Spring Boot?

Spring Boot is a framework for packaging the spring application with sensible defaults. What does this mean?. You are developing a web application using Spring MVC, Spring Data, Hibernate and Tomcat. How do you package and deploy this application to your web server. As of now, we have to manually write the configurations, XML files, etc. for deploying to web server.

Spring Boot does that for you with Zero XML configuration in your project. Believe me, you don't need deployment descriptor, web server, etc. Spring Boot is magical framework that bundles all the dependencies for you. Finally your web application will be a standalone JAR file with embeded servers.

If you are still confused how this works, please read about microservice framework development using spring boot.

What is Spring MVC?

It is a traditional web application framework that helps you to build web applications. It is similar to Struts framework.

A Spring MVC is a Java framework which is used to build web applications. It follows the Model-View-Controller design pattern. It implements all the basic features of a core spring framework like Inversion of Control, Dependency Injection.

A Spring MVC provides an elegant solution to use MVC in spring framework by the help of DispatcherServlet. Here, DispatcherServlet is a class that receives the incoming request and maps it to the right resource such as controllers, models, and views.

I hope this helps you to understand the difference.

How to check if a file exists in Documents folder?

If you set up your file system differently or looking for a different way of setting up a file system and then checking if a file exists in the documents folder heres an another example. also show dynamic checking

for (int i = 0; i < numberHere; ++i){
    NSFileManager* fileMgr = [NSFileManager defaultManager];
    NSString *documentsDirectory = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
    NSString* imageName = [NSString stringWithFormat:@"image-%@.png", i];
    NSString* currentFile = [documentsDirectory stringByAppendingPathComponent:imageName];
    BOOL fileExists = [fileMgr fileExistsAtPath:currentFile];
    if (fileExists == NO){
        cout << "DOESNT Exist!" << endl;
    } else {
        cout << "DOES Exist!" << endl;
    }
}

Comparing two maps

As long as you override equals() on each key and value contained in the map, then m1.equals(m2) should be reliable to check for maps equality.

The same result can be obtained also by comparing toString() of each map as you suggested, but using equals() is a more intuitive approach.

May not be your specific situation, but if you store arrays in the map, may be a little tricky, because they must be compared value by value, or using Arrays.equals(). More details about this see here.