Programs & Examples On #Iaas

IAAS (Infrastructure as a Service) is a provision model in which an organization outsources the equipment used to support operations, including storage, hardware, servers and networking components. The service provider owns the equipment and is responsible for housing, running and maintaining it.

What is SaaS, PaaS and IaaS? With examples

Iam sharing my experiences along with Standard definitions by NIST. Iam developer from product company and we own database and client (eco system). Beside many clear pictures the confusion arises because of many actors(5 defined by NIST) and things differ from prespectives.

For IaaS and Bare metal deployments we sell licenses and packages can be obtained from CD's or FTP server (rpms). The code is compiled tested and delivered. Here our customers pay to us (license cost) and/or to cloud provider for instances.

We partner with cloud providers (technology partner) to sell our products via marketplace.

Typically we deliver images (ami,vhd,etc) + some (cloud formation templates or ARM templates, etc) in case of PaaS. We have Jenkins pipelines to place them in market place (version based). Here with some skills developers can login into instances and manipulate the software (e.g after database instances are launched login and completely remove the software and make it look like just EC2 instances)

In case of SaaS our Jenkins pipelines will directly deploy (whether they are web apps, azure/lambda functions). Neither developers/end users have less control over the physical hardware.

Below are the Actors defined by NIST and since developers(tech company that provides software) partners with cloud provider, developers best match is cloud provider.

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Fixed digits after decimal with f-strings

Adding to Rob?'s answer: in case you want to print rather large numbers, using thousand separators can be a great help (note the comma).

>>> f'{a*1000:,.2f}'
'10,123.40'

How to find the statistical mode?

One more solution, which works for both numeric & character/factor data:

Mode <- function(x) {
  ux <- unique(x)
  ux[which.max(tabulate(match(x, ux)))]
}

On my dinky little machine, that can generate & find the mode of a 10M-integer vector in about half a second.

If your data set might have multiple modes, the above solution takes the same approach as which.max, and returns the first-appearing value of the set of modes. To return all modes, use this variant (from @digEmAll in the comments):

Modes <- function(x) {
  ux <- unique(x)
  tab <- tabulate(match(x, ux))
  ux[tab == max(tab)]
}

Is it possible to set ENV variables for rails development environment in my code?

Script for loading of custom .env file: Add the following lines to /config/environment.rb, between the require line, and the Application.initialize line:

# Load the app's custom environment variables here, so that they are loaded before environments/*.rb

app_environment_variables = File.join(Rails.root, 'config', 'local_environment.env')
if File.exists?(app_environment_variables)
  lines = File.readlines(app_environment_variables)
  lines.each do |line|
    line.chomp!
    next if line.empty? or line[0] == '#'
    parts = line.partition '='
    raise "Wrong line: #{line} in #{app_environment_variables}" if parts.last.empty?
    ENV[parts.first] = parts.last
  end
end

And config/local_environment.env (you will want to .gitignore it) will look like:

# This is ignored comment
DATABASE_URL=mysql2://user:[email protected]:3307/database
RACK_ENV=development

(Based on solution of @user664833)

How can I align the columns of tables in Bash?

Use column command:

column -t -s' ' filename

How to get store information in Magento?

Great answers here. If you're looking for the default view "Store Name" set in the Magento configuration:

Mage::app()->getStore()->getFrontendName()

Selenium 2.53 not working on Firefox 47

Firefox 47.0 stopped working with Webdriver.

Easiest solution is to switch to Firefox 47.0.1 and Webdriver 2.53.1. This combination again works. In fact, restoring Webdriver compatibility was the main reason behind the 47.0.1 release, according to https://www.mozilla.org/en-US/firefox/47.0.1/releasenotes/.

document.getElementById().value doesn't set the value

Your response is almost certainly a string. You need to make sure it gets converted to a number:

document.getElementById("points").value= new Number(request.responseText);

You might take a closer look at your responseText. It sound like you are getting a string that contains quotes. If you are getting JSON data via AJAX, you might have more consistent results running it through JSON.parse().

document.getElementById("points").value= new Number(JSON.parse(request.responseText));

Is calling destructor manually always a sign of bad design?

Any time you need to separate allocation from initialization, you'll need placement new and explicit calling of the destructor manually. Today, it's rarely necessary, since we have the standard containers, but if you have to implement some new sort of container, you'll need it.

How to copy only a single worksheet to another workbook using vba

The much longer example below combines some of the useful snippets above:

  • You can specify any number of sheets you want to copy across
  • You can copy entire sheets, i.e. like dragging the tab across, or you can copy over the contents of cells as values-only but preserving formatting.

It could still do with a lot of work to make it better (better error-handling, general cleaning up), but it hopefully provides a good start.

Note that not all formatting is carried across because the new sheet uses its own theme's fonts and colours. I can't work out how to copy those across when pasting as values only.

 Option Explicit

Sub copyDataToNewFile()
    Application.ScreenUpdating = False

    ' Allow different ways of copying data:
    ' sheet = copy the entire sheet
    ' valuesWithFormatting = create a new sheet with the same name as the
    '                        original, copy values from the cells only, then
    '                        apply original formatting. Formatting is only as
    '                        good as the Paste Special > Formats command - theme
    '                        colours and fonts are not preserved.
    Dim copyMethod As String
    copyMethod = "valuesWithFormatting"

    Dim newFilename As String           ' Name (+optionally path) of new file
    Dim themeTempFilePath As String     ' To temporarily save the source file's theme

    Dim sourceWorkbook As Workbook      ' This file
    Set sourceWorkbook = ThisWorkbook

    Dim newWorkbook As Workbook         ' New file

    Dim sht As Worksheet                ' To iterate through sheets later on.
    Dim sheetFriendlyName As String     ' To store friendly sheet name
    Dim sheetCount As Long              ' To avoid having to count multiple times

    ' Sheets to copy over, using internal code names as more reliable.
    Dim colSheetObjectsToCopy As New Collection
    colSheetObjectsToCopy.Add Sheet1
    colSheetObjectsToCopy.Add Sheet2

    ' Get filename of new file from user.
    Do
        newFilename = InputBox("Please Specify the name of your new workbook." & vbCr & vbCr & "Either enter a full path or just a filename, in which case the file will be saved in the same location (" & sourceWorkbook.Path & "). Don't use the name of a workbook that is already open, otherwise this script will break.", "New Copy")
        If newFilename = "" Then MsgBox "You must enter something.", vbExclamation, "Filename needed"
    Loop Until newFilename > ""

    ' If they didn't supply a path, assume same location as the source workbook.
    ' Not perfect - simply assumes a path has been supplied if a path separator
    ' exists somewhere. Could still be a badly-formed path. And, no check is done
    ' to see if the path actually exists.
    If InStr(1, newFilename, Application.PathSeparator, vbTextCompare) = 0 Then
        newFilename = sourceWorkbook.Path & Application.PathSeparator & newFilename
    End If

    ' Create a new workbook and save as the user requested.
    ' NB This fails if the filename is the same as a workbook that's
    ' already open - it should check for this.
    Set newWorkbook = Application.Workbooks.Add(xlWBATWorksheet)
    newWorkbook.SaveAs Filename:=newFilename, _
        FileFormat:=xlWorkbookDefault

    ' Theme fonts and colours don't get copied over with most paste-special operations.
    ' This saves the theme of the source workbook and then loads it into the new workbook.
    ' BUG: Doesn't work!
    'themeTempFilePath = Environ("temp") & Application.PathSeparator & sourceWorkbook.Name & " - Theme.xml"
    'sourceWorkbook.Theme.ThemeFontScheme.Save themeTempFilePath
    'sourceWorkbook.Theme.ThemeColorScheme.Save themeTempFilePath
    'newWorkbook.Theme.ThemeFontScheme.Load themeTempFilePath
    'newWorkbook.Theme.ThemeColorScheme.Load themeTempFilePath
    'On Error Resume Next
    'Kill themeTempFilePath  ' kill = delete in VBA-speak
    'On Error GoTo 0


    ' getWorksheetNameFromObject returns null if the worksheet object doens't
    ' exist
    For Each sht In colSheetObjectsToCopy
        sheetFriendlyName = getWorksheetNameFromObject(sourceWorkbook, sht)
        Application.StatusBar = "VBL Copying " & sheetFriendlyName
        If Not IsNull(sheetFriendlyName) Then
            Select Case copyMethod
                Case "sheet"
                    sourceWorkbook.Sheets(sheetFriendlyName).Copy _
                        After:=newWorkbook.Sheets(newWorkbook.Sheets.count)
                Case "valuesWithFormatting"
                    newWorkbook.Sheets.Add After:=newWorkbook.Sheets(newWorkbook.Sheets.count), _
                        Type:=sourceWorkbook.Sheets(sheetFriendlyName).Type
                    sheetCount = newWorkbook.Sheets.count
                    newWorkbook.Sheets(sheetCount).Name = sheetFriendlyName
                    ' Copy all cells in current source sheet to the clipboard. Could copy straight
                    ' to the new workbook by specifying the Destination parameter but in this case
                    ' we want to do a paste special as values only and the Copy method doens't allow that.
                    sourceWorkbook.Sheets(sheetFriendlyName).Cells.Copy ' Destination:=newWorkbook.Sheets(newWorkbook.Sheets.Count).[A1]
                    newWorkbook.Sheets(sheetCount).[A1].PasteSpecial Paste:=xlValues
                    newWorkbook.Sheets(sheetCount).[A1].PasteSpecial Paste:=xlFormats
                    newWorkbook.Sheets(sheetCount).Tab.Color = sourceWorkbook.Sheets(sheetFriendlyName).Tab.Color
                    Application.CutCopyMode = False
            End Select
        End If
    Next sht

    Application.StatusBar = False
    Application.ScreenUpdating = True
    ActiveWorkbook.Save

jquery/javascript convert date string to date

var stringDate = "Sunday, February 28, 2010";

var months = ["January", "February", "March"]; // You add the rest  :-)

var m = /(\w+) (\d+), (\d+)/.exec(stringDate);

var date = new Date(+m[3], months.indexOf(m[1]), +m[2]);

The indexOf method on arrays is only supported on newer browsers (i.e. not IE). You'll need to do the searching yourself or use one of the many libraries that provide the same functionality.

Also the code is lacking any error checking which should be added. (String not matching the regular expression, non existent months, etc.)

How to split a string in two and store it in a field

I would suggest the following:

String[] parsedInput = str.split("\n"); String firstName = parsedInput[0].split(": ")[1]; String lastName = parsedInput[1].split(": ")[1]; myMap.put(firstName,lastName); 

How do you get centered content using Twitter Bootstrap?

You need to adjust with the .span.

Example:

<div class="container-fluid">
  <div class="row-fluid">
    <div class="span4"></div>
    <!--/span-->
    <div class="span4" align="center">
      <div class="hero-unit" align="center">
        <h3>Sign In</h3>
        <form>
          <div class="input-prepend">
            <span class="add-on"><i class="icon-envelope"></i> </span>
            <input class="span6" type="text" placeholder="Email address">
          </div>
          <div class="input-prepend">
            <span class="add-on"><i class="icon-key"></i> </span>
            <input class="span6" type="password" placeholder="Password">
          </div>
        </form>
      </div>
    </div>
    <!-- /span -->
    <div class="span4"></div>
  </div>
  <!-- /row -->
</div>

C++ program converts fahrenheit to celsius

Best way would be

#include <iostream>                        
using namespace std;                       

int main() {                               
    float celsius;                         
    float fahrenheit;

    cout << "Enter Celsius temperature: "; 
    cin >> celsius;
    fahrenheit = (celsius * 1.8) + 32;// removing division for the confusion
    cout << "Fahrenheit = " << fahrenheit << endl;

    return 0;                             
}

:)

Escaping ampersand in URL

This does not only apply to the ampersand in URLs, but to all reserved characters. Some of which include:

 # $ & + ,  / : ; = ? @ [ ]

The idea is the same as encoding an &in an HTML document, but the context has changed to be within the URI, in addition to being within the HTML document. So, the percent-encoding prevents issues with parsing inside of both contexts.

The place where this comes in handy a lot is when you need to put a URL inside of another URL. For example, if you want to post a status on Twitter:

http://www.twitter.com/intent/tweet?status=What%27s%20up%2C%20StackOverflow%3F(http%3A%2F%2Fwww.stackoverflow.com)

There's lots of reserved characters in my Tweet, namely ?'():/, so I encoded the whole value of the status URL parameter. This also is helpful when using mailto: links that have a message body or subject, because you need to encode the body and subject parameters to keep line breaks, ampersands, etc. intact.

When a character from the reserved set (a "reserved character") has special meaning (a "reserved purpose") in a certain context, and a URI scheme says that it is necessary to use that character for some other purpose, then the character must be percent-encoded. Percent-encoding a reserved character involves converting the character to its corresponding byte value in ASCII and then representing that value as a pair of hexadecimal digits. The digits, preceded by a percent sign ("%") which is used as an escape character, are then used in the URI in place of the reserved character. (For a non-ASCII character, it is typically converted to its byte sequence in UTF-8, and then each byte value is represented as above.) The reserved character "/", for example, if used in the "path" component of a URI, has the special meaning of being a delimiter between path segments. If, according to a given URI scheme, "/" needs to be in a path segment, then the three characters "%2F" or "%2f" must be used in the segment instead of a raw "/".

http://en.wikipedia.org/wiki/Percent-encoding#Percent-encoding_reserved_characters

Difference between uint32 and uint32_t

uint32_t is defined in the standard, in

18.4.1 Header <cstdint> synopsis [cstdint.syn]

namespace std {
//...
typedef unsigned integer type uint32_t; // optional
//...
}

uint32 is not, it's a shortcut provided by some compilers (probably as typedef uint32_t uint32) for ease of use.

Error Running React Native App From Terminal (iOS)

You may need to install or set the location of the Xcode Command Line Tools.

Via command line

If you have Xcode downloaded you can run the following to set the path:

sudo xcode-select -s /Applications/Xcode.app

If the command line tools haven't been installed yet, you may need to run this first:

xcode-select --install

You may need to accept the Xcode license before installing command line tools:

sudo xcodebuild -license accept 

Via Xcode

Or adjust the Command Line Tools setting via Xcode (Xcode > Preferences > Locations):

Xcode preferences - Locations tab

Protect image download

There is no way to protect image downloading. This is because the image has to be downloaded by the browser for it to be seen by the user. There are tricks (like the transparent background you specified) to restrict certain operations like image right click and saving to browser cache folder, but there isn't a way for truly protecting the images.

Typescript: Type X is missing the following properties from type Y length, pop, push, concat, and 26 more. [2740]

I had the same problem and I solved as follows define an interface like mine

export class Notification {
    id: number;
    heading: string;
    link: string;
}

and in nofificationService write

allNotifications: Notification[]; 
  //NotificationDetail: Notification;  
  private notificationsUrl = 'assets/data/notification.json';  // URL to web api 
  private downloadsUrl = 'assets/data/download.json';  // URL to web api 

  constructor(private httpClient: HttpClient ) { }

  getNotifications(): Observable<Notification[]> {    
       //return this.allNotifications = this.NotificationDetail.slice(0);  
     return this.httpClient.get<Notification[]>

(this.notificationsUrl).pipe(map(res => this.allNotifications = res))
      } 

and in component write

 constructor(private notificationService: NotificationService) {
   }

  ngOnInit() {
      /* get Notifications */
      this.notificationService.getNotifications().subscribe(data => this.notifications = data);
}

Environment Variable with Maven

I suggest using the amazing tool direnv. With it you can inject environment variables once you cd into the project. These steps worked for me:

.envrc file

source_up
dotenv

.env file

_JAVA_OPTIONS="-DYourEnvHere=123"

Check if item is in an array / list

Assuming you mean "list" where you say "array", you can do

if item in my_list:
    # whatever

This works for any collection, not just for lists. For dictionaries, it checks whether the given key is present in the dictionary.

Binding a Button's visibility to a bool value in ViewModel

2 way conversion in c# from boolean to visibility

using System;
using System.Windows;
using System.Windows.Data;

namespace FaceTheWall.converters
{
    class BooleanToVisibilityConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            if (value is Boolean && (bool)value)
            {
                return Visibility.Visible;
            }
            return Visibility.Collapsed;
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            if (value is Visibility && (Visibility)value == Visibility.Visible)
            {
                return true;
            }
            return false;
        }
    }
}

How to construct a WebSocket URI relative to the page URI?

easy:

location.href.replace(/^http/, 'ws') + '/to/ws'
// or if you hate regexp:
location.href.replace('http://', 'ws://').replace('https://', 'wss://') + '/to/ws'

Android - Launcher Icon Size

I had the same problem but then realized the arrangement of my icon graphic within the square allowed (512 x 512 in my case) was not maximized. So I rotated the image and was able to scale it up to fill the corners better. Then I right clicked on my res folder in my project in Android Studio, then choose New then Image Asset, it took me through a wizard where I got to select my image file to use. Then if you check the box that says "Trim surrounding blank space", it makes sure all edges, that are able, touch the sides of your square. These steps got it much bigger than the original.

Release generating .pdb files, why?

Why are you so sure you will not debug release builds? Sometimes (hopefully rarely but happens) you may get a defect report from a customer that is not reproducible in the debug version for some reason (different timings, small different behaviour or whatever). If that issue appears to be reproducible in the release build you'll be happy to have the matching pdb.

Deprecated Gradle features were used in this build, making it incompatible with Gradle 5.0

It was fixed this kind of error after migrate to AndroidX

  • Go to Refactor ---> Migrate to AndroidX

jQuery Keypress Arrow Keys

$(document).on( "keydown",  keyPressed);

function keyPressed (e){
    e = e || window.e;
    var newchar = e.which || e.keyCode;
    alert(newchar)
}

Naming threads and thread-pools of ExecutorService

Extend ThreadFactory

public interface ThreadFactory

An object that creates new threads on demand. Using thread factories removes hardwiring of calls to new Thread, enabling applications to use special thread subclasses, priorities, etc.

Thread newThread(Runnable r)

Constructs a new Thread. Implementations may also initialize priority, name, daemon status, ThreadGroup, etc.

Sample code:

import java.util.concurrent.*;
import java.util.concurrent.atomic.*;

import java.util.concurrent.ThreadPoolExecutor.DiscardPolicy;

class SimpleThreadFactory implements ThreadFactory {
   String name;
   AtomicInteger threadNo = new AtomicInteger(0);

   public SimpleThreadFactory (String name){
       this.name = name;
   }
   public Thread newThread(Runnable r) {
     String threadName = name+":"+threadNo.incrementAndGet();
     System.out.println("threadName:"+threadName);
     return new Thread(r,threadName );
   }
   public static void main(String args[]){
        SimpleThreadFactory factory = new SimpleThreadFactory("Factory Thread");
        ThreadPoolExecutor executor= new ThreadPoolExecutor(1,1,60,
                    TimeUnit.SECONDS,new ArrayBlockingQueue<Runnable>(1),new ThreadPoolExecutor.DiscardPolicy());


        final ExecutorService executorService = Executors.newFixedThreadPool(5,factory);

        for ( int i=0; i < 100; i++){
            executorService.submit(new Runnable(){
                 public void run(){
                    System.out.println("Thread Name in Runnable:"+Thread.currentThread().getName());
                 }
            });
        }
        executorService.shutdown();
    }
 }

output:

java SimpleThreadFactory

thread no:1
thread no:2
Thread Name in Runnable:Factory Thread:1
Thread Name in Runnable:Factory Thread:2
thread no:3
thread no:4
Thread Name in Runnable:Factory Thread:3
Thread Name in Runnable:Factory Thread:4
thread no:5
Thread Name in Runnable:Factory Thread:5

....etc

SSH SCP Local file to Remote in Terminal Mac Os X

At first, you need to add : after the IP address to indicate the path is following:

scp magento.tar.gz [email protected]:/var/www

I don't think you need to sudo the scp. In this case it doesn't affect the remote machine, only the local command.

Then if your user@xx.x.x.xx doesn't have write access to /var/www then you need to do it in 2 times:

Copy to remote server in your home folder (: represents your remote home folder, use :subfolder/ if needed, or :/home/user/ for full path):

scp magento.tar.gz [email protected]:

Then SSH and move the file:

ssh [email protected]
sudo mv magento.tar.gz /var/www

execute function after complete page load

this may work for you :

document.addEventListener('DOMContentLoaded', function() {
   // your code here
}, false);

or if your comfort with jquery,

$(document).ready(function(){
// your code
});

$(document).ready() fires on DOMContentLoaded, but this event is not being fired consistently among browsers. This is why jQuery will most probably implement some heavy workarounds to support all the browsers. And this will make it very difficult to "exactly" simulate the behavior using plain Javascript (but not impossible of course).

as Jeffrey Sweeney and J Torres suggested, i think its better to have a setTimeout function, before firing the function like below :

setTimeout(function(){
 //your code here
}, 3000);

How to set Meld as git mergetool

It took a few permutations to get meld working on windows for me. This is my current .gitconfig:

[merge]
    conflictstyle = diff3
    tool = meld
[mergetool "meld"]
    cmd = \"C:\\Program Files (x86)\\Meld\\Meld.exe\" --auto-merge \"$LOCAL\" \"$BASE\" \"$REMOTE\" --output \"$MERGED\"

Linux:

[merge]
    conflictstyle = diff3
    tool = meld
[mergetool "meld"]
    cmd = meld --auto-merge $LOCAL $BASE $REMOTE --output=$MERGED --diff $BASE $LOCAL --diff $BASE $REMOTE

I believe adding conflictstyle = diff3 changes the inline text to include BASE contents in the output file before meld gets to it, which might give it a head start. Not sure.

Now, since I already noted Meld supports three-way merging, there is another option. When “diff3” git conflict style is set, Meld prints “(??)” on the line showing the content from BASE. source

A few meld command line features I really like:

  • --auto-merge does a great job at choosing the right thing for you (it's not bulletproof, but I consider the time saved to be worth any risk).

  • You can add extra diff windows in the same command. E.g.:

    --diff $BASE $LOCAL --diff $BASE $REMOTE

    will add two more tabs with the local and incoming patch diffs. These can be quite useful to see separately from the 3 way view to see separate diffs from the base in each branch. I could't get this working on windows though.

  • Some version of meld allow you to label tabs with --label. This was more important before git fixed the names of the files passed to meld to include local/base/remote.

  • The order of --diff can affect the tab order. I had trouble in some older versions that were putting the additional diffs first, when the main 3 way diff is far more frequently used.

Timeout a command in bash without unnecessary delay

Here is a version that does not rely on spawning a child process - I needed a standalone script which embedded this functionality. It also does a fractional poll interval, so you can poll quicker. timeout would have been preferred - but I'm stuck on an old server

# wait_on_command <timeout> <poll interval> command
wait_on_command()
{
    local timeout=$1; shift
    local interval=$1; shift
    $* &
    local child=$!

    loops=$(bc <<< "($timeout * (1 / $interval)) + 0.5" | sed 's/\..*//g')
    ((t = loops))
    while ((t > 0)); do
        sleep $interval
        kill -0 $child &>/dev/null || return
        ((t -= 1))
    done

    kill $child &>/dev/null || kill -0 $child &>/dev/null || return
    sleep $interval
    kill -9 $child &>/dev/null
    echo Timed out
}

slow_command()
{
    sleep 2
    echo Completed normally
}

# wait 1 sec in 0.1 sec increments
wait_on_command 1 0.1 slow_command

# or call an external command
wait_on_command 1 0.1 sleep 10

How do I parse an ISO 8601-formatted date?

Django's parse_datetime() function supports dates with UTC offsets:

parse_datetime('2016-08-09T15:12:03.65478Z') =
datetime.datetime(2016, 8, 9, 15, 12, 3, 654780, tzinfo=<UTC>)

So it could be used for parsing ISO 8601 dates in fields within entire project:

from django.utils import formats
from django.forms.fields import DateTimeField
from django.utils.dateparse import parse_datetime

class DateTimeFieldFixed(DateTimeField):
    def strptime(self, value, format):
        if format == 'iso-8601':
            return parse_datetime(value)
        return super().strptime(value, format)

DateTimeField.strptime = DateTimeFieldFixed.strptime
formats.ISO_INPUT_FORMATS['DATETIME_INPUT_FORMATS'].insert(0, 'iso-8601')

What are the best JVM settings for Eclipse?

My own settings (Java 1.7, modify for 1.6):

-vm
C:/Program Files (x86)/Java/jdk1.7.0/bin
-startup
plugins/org.eclipse.equinox.launcher_1.1.0.v20100507.jar
--launcher.library
plugins/org.eclipse.equinox.launcher.win32.win32.x86_1.1.100.v20100628
-showsplash
org.eclipse.platform
--launcher.XXMaxPermSize
256m
--launcher.defaultAction
openFile
-vmargs
-server
-Dosgi.requiredJavaVersion=1.7
-Xmn100m
-Xss1m
-XgcPrio:deterministic
-XpauseTarget:20
-XX:PermSize=400M
-XX:MaxPermSize=500M
-XX:CompileThreshold=10
-XX:MaxGCPauseMillis=10
-XX:MaxHeapFreeRatio=70
-XX:+UnlockExperimentalVMOptions
-XX:+DoEscapeAnalysis
-XX:+UseG1GC
-XX:+UseFastAccessorMethods
-XX:+AggressiveOpts
-Xms512m
-Xmx512m

How to get a random number between a float range?

Use random.uniform(a, b):

>>> random.uniform(1.5, 1.9)
1.8733202628557872

How can I get a random number in Kotlin?

Another way of implementing s1m0nw1's answer would be to access it through a variable. Not that its any more efficient but it saves you from having to type ().

val ClosedRange<Int>.random: Int
    get() = Random().nextInt((endInclusive + 1) - start) +  start 

And now it can be accessed as such

(1..10).random

Remove a symlink to a directory

Assuming your setup is something like: ln -s /mnt/bar ~/foo, then you should be able to do a rm foo with no problem. If you can't, make sure you are the owner of the foo and have permission to write/execute the file. Removing foo will not touch bar, unless you do it recursively.

Cannot find firefox binary in PATH. Make sure firefox is installed. OS appears to be: VISTA

The simplest way is to use the below code before you define your Driver.

System.setProperty("webdriver.firefox.bin",
                    "C:\\Program Files (x86)\\Mozilla Firefox\\firefox.exe");

How to convert a private key to an RSA private key?

This may be of some help (do not literally write out the backslashes '\' in the commands, they are meant to indicate that "everything has to be on one line"):

Which Command to Apply When

It seems that all the commands (in grey) take any type of key file (in green) as "in" argument. Which is nice.

Here are the commands again for easier copy-pasting:

openssl rsa                                                -in $FF -out $TF
openssl rsa -aes256                                        -in $FF -out $TF
openssl pkcs8 -topk8 -nocrypt                              -in $FF -out $TF
openssl pkcs8 -topk8 -v2 aes-256-cbc -v2prf hmacWithSHA256 -in $FF -out $TF

and

openssl rsa -check -in $FF
openssl rsa -text  -in $FF

How to print something to the console in Xcode?

In some environments, NSLog() will be unresponsive. But there are other ways to get output...

NSString* url = @"someurlstring";
printf("%s", [url UTF8String]);

By using printf with the appropriate parameters, we can display things this way. This is the only way I have found to work on online Objective-C sandbox environments.

Disable scrolling in an iPhone web application?

The page has to be launched from the Home screen for the meta tag to work.

How do I compare strings in Java?

I agree with the answer from zacherates.

But what you can do is to call intern() on your non-literal strings.

From zacherates example:

// ... but they are not the same object
new String("test") == "test" ==> false 

If you intern the non-literal String equality is true:

new String("test").intern() == "test" ==> true 

How to debug a GLSL shader?

You can try this: https://github.com/msqrt/shader-printf which is an implementation called appropriately "Simple printf functionality for GLSL."

You might also want to try ShaderToy, and maybe watch a video like this one (https://youtu.be/EBrAdahFtuo) from "The Art of Code" YouTube channel where you can see some of the techniques that work well for debugging and visualising. I can strongly recommend his channel as he writes some really good stuff and he also has a knack for presenting complex ideas in novel, highly engaging and and easy to digest formats (His Mandelbrot video is a superb example of exactly that : https://youtu.be/6IWXkV82oyY)

I hope nobody minds this late reply, but the question ranks high on Google searches for GLSL debugging and much has of course changed in 9 years :-)

PS: Other alternatives could also be NVIDIA nSight and AMD ShaderAnalyzer which offer a full stepping debugger for shaders.

Draw line in UIView

The easiest way in your case (horizontal line) is to add a subview with black background color and frame [0, 200, 320, 1].

Code sample (I hope there are no errors - I wrote it without Xcode):

UIView *lineView = [[UIView alloc] initWithFrame:CGRectMake(0, 200, self.view.bounds.size.width, 1)];
lineView.backgroundColor = [UIColor blackColor];
[self.view addSubview:lineView];
[lineView release];
// You might also keep a reference to this view 
// if you are about to change its coordinates.
// Just create a member and a property for this...

Another way is to create a class that will draw a line in its drawRect method (you can see my code sample for this here).

What are the rules for JavaScript's automatic semicolon insertion (ASI)?

Straight from the ECMA-262, Fifth Edition ECMAScript Specification:

7.9.1 Rules of Automatic Semicolon Insertion

There are three basic rules of semicolon insertion:

  1. When, as the program is parsed from left to right, a token (called the offending token) is encountered that is not allowed by any production of the grammar, then a semicolon is automatically inserted before the offending token if one or more of the following conditions is true:
    • The offending token is separated from the previous token by at least one LineTerminator.
    • The offending token is }.
  2. When, as the program is parsed from left to right, the end of the input stream of tokens is encountered and the parser is unable to parse the input token stream as a single complete ECMAScript Program, then a semicolon is automatically inserted at the end of the input stream.
  3. When, as the program is parsed from left to right, a token is encountered that is allowed by some production of the grammar, but the production is a restricted production and the token would be the first token for a terminal or nonterminal immediately following the annotation "[no LineTerminator here]" within the restricted production (and therefore such a token is called a restricted token), and the restricted token is separated from the previous token by at least one LineTerminator, then a semicolon is automatically inserted before the restricted token.

However, there is an additional overriding condition on the preceding rules: a semicolon is never inserted automatically if the semicolon would then be parsed as an empty statement or if that semicolon would become one of the two semicolons in the header of a for statement (see 12.6.3).

How to use Visual Studio C++ Compiler?

You may be forgetting something. Before #include <iostream>, write #include <stdafx.h> and maybe that will help. Then, when you are done writing, click test, than click output from build, then when it is done processing/compiling, press Ctrl+F5 to open the Command Prompt and it should have the output and "press any key to continue."

html form - make inputs appear on the same line

Try just putting a div around the first and last name inputs/labels like this:

<div class="name">
        <label for="First_Name">First Name:</label>
        <input name="first_name" id="First_Name" type="text" />

        <label for="Name">Last Name:</label>
        <input name="last_name" id="Last_Name" type="text" /> 
</div>

Look at the fiddle here: http://jsfiddle.net/XAkXg/

How do I set the classpath in NetBeans?

  1. Right-click your Project.
  2. Select Properties.
  3. On the left-hand side click Libraries.
  4. Under Compile tab - click Add Jar/Folder button.

Or

  1. Expand your Project.
  2. Right-click Libraries.
  3. Select Add Jar/Folder.

Reading PDF content with itextsharp dll in VB.NET or C#

Here is a VB.NET solution based on ShravankumarKumar's solution.

This will ONLY give you the text. The images are a different story.

Public Shared Function GetTextFromPDF(PdfFileName As String) As String
    Dim oReader As New iTextSharp.text.pdf.PdfReader(PdfFileName)

    Dim sOut = ""

    For i = 1 To oReader.NumberOfPages
        Dim its As New iTextSharp.text.pdf.parser.SimpleTextExtractionStrategy

        sOut &= iTextSharp.text.pdf.parser.PdfTextExtractor.GetTextFromPage(oReader, i, its)
    Next

    Return sOut
End Function

Java: Simplest way to get last word in a string

If other whitespace characters are possible, then you'd want:

testString.split("\\s+");

Count the frequency that a value occurs in a dataframe column

If your DataFrame has values with the same type, you can also set return_counts=True in numpy.unique().

index, counts = np.unique(df.values,return_counts=True)

np.bincount() could be faster if your values are integers.

Python: Select subset from list based on index set

I see 2 options.

  1. Using numpy:

    property_a = numpy.array([545., 656., 5.4, 33.])
    property_b = numpy.array([ 1.2,  1.3, 2.3, 0.3])
    good_objects = [True, False, False, True]
    good_indices = [0, 3]
    property_asel = property_a[good_objects]
    property_bsel = property_b[good_indices]
    
  2. Using a list comprehension and zip it:

    property_a = [545., 656., 5.4, 33.]
    property_b = [ 1.2,  1.3, 2.3, 0.3]
    good_objects = [True, False, False, True]
    good_indices = [0, 3]
    property_asel = [x for x, y in zip(property_a, good_objects) if y]
    property_bsel = [property_b[i] for i in good_indices]
    

Trim Whitespaces (New Line and Tab space) in a String in Oracle

TRIM(BOTH chr(13)||chr(10)||' ' FROM str)

Qt. get part of QString

Use the left function:

QString yourString = "This is a string";
QString leftSide = yourString.left(5);
qDebug() << leftSide; // output "This "

Also have a look at mid() if you want more control.

How to completely uninstall kubernetes

In my "Ubuntu 16.04", I use next steps to completely remove and clean Kubernetes (installed with "apt-get"):

kubeadm reset
sudo apt-get purge kubeadm kubectl kubelet kubernetes-cni kube*   
sudo apt-get autoremove  
sudo rm -rf ~/.kube

And restart the computer.

vuejs update parent data from child component

Child Component

Use this.$emit('event_name') to send an event to the parent component.

enter image description here

Parent Component

In order to listen to that event in the parent component, we do v-on:event_name and a method (ex. handleChange) that we want to execute on that event occurs

enter image description here

Done :)

Find if a textbox is disabled or not using jquery

.prop('disabled') will return a Boolean:

var isDisabled = $('textbox').prop('disabled');

Here's the fiddle: http://jsfiddle.net/unhjM/

Select all from table with Laravel and Eloquent

using DB facade you can perform SQL queries

 public function index()
{
    return DB::table('table_name')->get();
}

Declaring a boolean in JavaScript using just var

The variable will become what ever type you assign it. Initially it is undefined. If you assign it 'true' it will become a string, if you assign it true it will become a boolean, if you assign it 1 it will become a number. Subsequent assignments may change the type of the variable later.

Selecting last element in JavaScript array

var last = array.slice(-1)[0];

I find slice at -1 useful for getting the last element (especially of an array of unknown length) and the performance is much better than calculating the length less 1.

Mozilla Docs on Slice

Performance of the various methods for selecting last array element

Does C# have an equivalent to JavaScript's encodeURIComponent()?

Try Server.UrlEncode(), or System.Web.HttpUtility.UrlEncode() for instances when you don't have access to the Server object. You can also use System.Uri.EscapeUriString() to avoid adding a reference to the System.Web assembly.

Casting objects in Java

Casting is necessary to tell that you are calling a child and not a parent method. So it's ever downward. However if the method is already defined in the parent class and overriden in the child class, you don't any cast. Here an example:

class Parent{
   void method(){ System.out.print("this is the parent"); }
}

class Child extends Parent{
   @override
   void method(){ System.out.print("this is the child"); }
}
...
Parent o = new Child();
o.method();
((Child)o).method();  

The two method call will both print : "this is the child".

Commit only part of a file in Git

It's been 10 years since this question was asked. And I hope this answer will be useful to someone. As mentioned in the answer here, where GUI is not an option, Andrew Shadura's crecord extension helps bring a ncurses window in which we can select the lines to commit.

Set up the extension as follows:

git clone https://github.com/andrewshadura/git-crecord
cd git-crecord
./setup.py install
ln -s $PWD/git-crecord ~/.local/bin/git-crecord

cd to your git repo and invoke it as follows:

git crecord

This would bring up the ncurses interface which can be used as shown below. Pressing the following keys in the ncurses window will do certain actions:

f       hunk toggle fold (arrow keys can also be used)
space   toggle hunk selection
a       toggle commit or amend
c       confirm and open commit window

Screencast showing a sample usageExample

How do I get the different parts of a Flask request's url?

If you are using Python, I would suggest by exploring the request object:

dir(request)

Since the object support the method dict:

request.__dict__

It can be printed or saved. I use it to log 404 codes in Flask:

@app.errorhandler(404)
def not_found(e):
    with open("./404.csv", "a") as f:
        f.write(f'{datetime.datetime.now()},{request.__dict__}\n')
    return send_file('static/images/Darknet-404-Page-Concept.png', mimetype='image/png')

Auto increment in phpmyadmin

@AmitKB, Your procedure is correct. Although this error

Query error: #1075 - Incorrect table definition; there can be only one auto column and it must be defined as a key

can be solved by first marking the field as key(using the key icon with label primary),unless you have other key then it may not work.

Can't use SURF, SIFT in OpenCV

IN opencv3.x SIFT() & SURF() are no longer exist .for this

uninstall all the opencv versions

python -m pip uninstall opencv-python

python -m pip uninstall opencv-contrib-python

after that install opencv-contrib to include sift() and surf() using below given command with python(3.x)

python -m pip install opencv-contrib-python==3.4.2.16

then you can use

sift = cv2.xfeatures2d.SIFT_create()

Testing javascript with Mocha - how can I use console.log to debug a test?

If you are testing asynchronous code, you need to make sure to place done() in the callback of that asynchronous code. I had that issue when testing http requests to a REST API.

Count the number of commits on a Git branch

I like doing git shortlog -s -n --all. Gives you a "leaderboard" style list of names and number of commits.

jQuery UI Dialog individual CSS styling

The current version of dialog has the option "dialogClass" which you can use with your id's. For example,

$('foo').dialog({dialogClass:'dialog_style1'});

Then the CSS would be

.dialog_style1 {color:#aaa;}

Convert row to column header for Pandas DataFrame,

It would be easier to recreate the data frame. This would also interpret the columns types from scratch.

headers = df.iloc[0]
new_df  = pd.DataFrame(df.values[1:], columns=headers)

Customize Bootstrap checkboxes

As others have said, the style you're after is actually just the Mac OS checkbox style, so it will look radically different on other devices.

In fact both screenshots you linked show what checkboxes look like on Mac OS in Chrome, the grey one is shown at non-100% zoom levels.

phpMyAdmin - config.inc.php configuration?

Have a look at config.sample.inc.php: you will find examples of the configuration directives that you should copy to your config.inc.php (copy the missing ones). Then, have a look at examples/create_tables.sql which will help you create the missing tables.

The complete documentation for this is available at http://docs.phpmyadmin.net/en/latest/setup.html#phpmyadmin-configuration-storage.

How to remove carriage return and newline from a variable in shell script

use this command on your script file after copying it to Linux/Unix

perl -pi -e 's/\r//' scriptfilename

How to get the full URL of a Drupal page?

You can also do it this way:

$current_url = 'http://' .$_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];

It's a bit faster.

What does <> mean in excel?

It means "not equal to" (as in, the values in cells E37-N37 are not equal to "", or in other words, they are not empty.)

Python safe method to get value of nested dictionary

You could use get twice:

example_dict.get('key1', {}).get('key2')

This will return None if either key1 or key2 does not exist.

Note that this could still raise an AttributeError if example_dict['key1'] exists but is not a dict (or a dict-like object with a get method). The try..except code you posted would raise a TypeError instead if example_dict['key1'] is unsubscriptable.

Another difference is that the try...except short-circuits immediately after the first missing key. The chain of get calls does not.


If you wish to preserve the syntax, example_dict['key1']['key2'] but do not want it to ever raise KeyErrors, then you could use the Hasher recipe:

class Hasher(dict):
    # https://stackoverflow.com/a/3405143/190597
    def __missing__(self, key):
        value = self[key] = type(self)()
        return value

example_dict = Hasher()
print(example_dict['key1'])
# {}
print(example_dict['key1']['key2'])
# {}
print(type(example_dict['key1']['key2']))
# <class '__main__.Hasher'>

Note that this returns an empty Hasher when a key is missing.

Since Hasher is a subclass of dict you can use a Hasher in much the same way you could use a dict. All the same methods and syntax is available, Hashers just treat missing keys differently.

You can convert a regular dict into a Hasher like this:

hasher = Hasher(example_dict)

and convert a Hasher to a regular dict just as easily:

regular_dict = dict(hasher)

Another alternative is to hide the ugliness in a helper function:

def safeget(dct, *keys):
    for key in keys:
        try:
            dct = dct[key]
        except KeyError:
            return None
    return dct

So the rest of your code can stay relatively readable:

safeget(example_dict, 'key1', 'key2')

Checkout remote branch using git svn

Standard Subversion layout

Create a git clone of that includes your Subversion trunk, tags, and branches with

git svn clone http://svn.example.com/project -T trunk -b branches -t tags

The --stdlayout option is a nice shortcut if your Subversion repository uses the typical structure:

git svn clone http://svn.example.com/project --stdlayout

Make your git repository ignore everything the subversion repo does:

git svn show-ignore >> .git/info/exclude

You should now be able to see all the Subversion branches on the git side:

git branch -r

Say the name of the branch in Subversion is waldo. On the git side, you'd run

git checkout -b waldo-svn remotes/waldo

The -svn suffix is to avoid warnings of the form

warning: refname 'waldo' is ambiguous.

To update the git branch waldo-svn, run

git checkout waldo-svn
git svn rebase

Starting from a trunk-only checkout

To add a Subversion branch to a trunk-only clone, modify your git repository's .git/config to contain

[svn-remote "svn-mybranch"]
        url = http://svn.example.com/project/branches/mybranch
        fetch = :refs/remotes/mybranch

You'll need to develop the habit of running

git svn fetch --fetch-all

to update all of what git svn thinks are separate remotes. At this point, you can create and track branches as above. For example, to create a git branch that corresponds to mybranch, run

git checkout -b mybranch-svn remotes/mybranch

For the branches from which you intend to git svn dcommit, keep their histories linear!


Further information

You may also be interested in reading an answer to a related question.

Quick way to clear all selections on a multiselect enabled <select> with jQuery?

_x000D_
_x000D_
$('.clearAll').on('click', function() {_x000D_
  $('.dropdown').val([]);_x000D_
});
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
_x000D_
<select class="dropdown" multiple>_x000D_
  <option value="volvo">Volvo</option>_x000D_
  <option value="saab">Saab</option>_x000D_
  <option value="opel">Opel</option>_x000D_
  <option value="audi">Audi</option>_x000D_
</select>_x000D_
_x000D_
<button class='clearAll'>Clear All Selection</button>
_x000D_
_x000D_
_x000D_

Send cookies with curl

Very annoying, no cookie file exmpale on the official website https://ec.haxx.se/http/http-cookies.

Finnaly, I find it does not work, if your file content is just copyied like this

foo1=bar;foo2=bar2

I gusess the format must looks the style said by @Agustí Sánchez . You can test it by -c to create a cookie file on a website.

So try this way, it works

curl -H "Cookie:`cat ./my.cookie`"   http://xxxx.com

You can just copy the cookie from chrome console network tab.

HTML Form: Select-Option vs Datalist-Option

Datalist includes autocomplete and suggestions natively, it can also allow a user to enter a value that is not defined in the suggestions.

Select only gives you pre-defined options the user has to select from

How do I implement a callback in PHP?

I cringe every time I use create_function() in php.

Parameters are a coma separated string, the whole function body in a string... Argh... I think they could not have made it uglier even if they tried.

Unfortunately, it is the only choice when creating a named function is not worth the trouble.

wildcard * in CSS for classes

What you need is called attribute selector. An example, using your html structure, is the following:

div[class^="tocolor-"], div[class*=" tocolor-"] {
    color:red 
}

In the place of div you can add any element or remove it altogether, and in the place of class you can add any attribute of the specified element.

[class^="tocolor-"] — starts with "tocolor-".
[class*=" tocolor-"] — contains the substring "tocolor-" occurring directly after a space character.

Demo: http://jsfiddle.net/K3693/1/

More information on CSS attribute selectors, you can find here and here. And from MDN Docs MDN Docs

How do I concatenate strings and variables in PowerShell?

I just want to bring another way to do this using .NET String.Format:

$name = "Slim Shady"
Write-Host ([string]::Format("My name is {0}", $name))

Explanation of polkitd Unregistered Authentication Agent

I found this problem too. Because centos service depend on multi-user.target for none desktop Cenots 7.2. so I delete multi-user.target from my .service file. It had missed.

Convert an enum to List<string>

Use Enum's static method, GetNames. It returns a string[], like so:

Enum.GetNames(typeof(DataSourceTypes))

If you want to create a method that does only this for only one type of enum, and also converts that array to a List, you can write something like this:

public List<string> GetDataSourceTypes()
{
    return Enum.GetNames(typeof(DataSourceTypes)).ToList();
}

You will need Using System.Linq; at the top of your class to use .ToList()

How can I read numeric strings in Excel cells as string (not numbers)?

getStringCellValue returns NumberFormatException if the cell type is numeric. If you don't want to change the cell type to string, you can do this.

String rsdata = "";
try {
    rsdata = cell.getStringValue();
} catch (NumberFormatException ex) {
    rsdata = cell.getNumericValue() + "";
}

How to redirect stderr to null in cmd.exe

Your DOS command 2> nul

Read page Using command redirection operators. Besides the "2>" construct mentioned by Tanuki Software, it lists some other useful combinations.

What is the difference between response.sendRedirect() and request.getRequestDispatcher().forward(request,response)

1.redirect return the request to the browser from server,then resend the request to the server from browser.

2.forward send the request to another servlet (servlet to servlet).

Should you choose the MONEY or DECIMAL(x,y) datatypes in SQL Server?

Everything is dangerous if you don't know what you are doing

Even high-precision decimal types can't save the day:

declare @num1 numeric(38,22)
declare @num2 numeric(38,22)
set @num1 = .0000006
set @num2 = 1.0
select @num1 * @num2 * 1000000

1.000000 <- Should be 0.6000000


The money types are integers

The text representations of smallmoney and decimal(10,4) may look alike, but that doesn't make them interchangeable. Do you cringe when you see dates stored as varchar(10)? This is the same thing.

Behind the scenes, money/smallmoney are just a bigint/int The decimal point in the text representation of money is visual fluff, just like the dashes in a yyyy-mm-dd date. SQL doesn't actually store those internally.

Regarding decimal vs money, pick whatever is appropriate for your needs. The money types exist because storing accounting values as integer multiples of 1/10000th of unit is very common. Also, if you are dealing with actual money and calculations beyond simple addition and subtraction, you shouldn't be doing that at the database level! Do it at the application level with a library that supports Banker's Rounding (IEEE 754)

How to read data from java properties file using Spring Boot

We can read properties file in spring boot using 3 way

1. Read value from application.properties Using @Value

map key as

public class EmailService {

 @Value("${email.username}")
 private String username;

}

2. Read value from application.properties Using @ConfigurationProperties

In this we will map prefix of key using ConfigurationProperties and key name is same as field of class

  @Component
   @ConfigurationProperties("email")
    public class EmailConfig {

        private String   username;
    }

3. Read application.properties Using using Environment object

public class EmailController {

@Autowired
private Environment env;

@GetMapping("/sendmail")
public void sendMail(){     
    System.out.println("reading value from application properties file  using Environment ");
    System.out.println("username ="+ env.getProperty("email.username"));
    System.out.println("pwd ="+ env.getProperty("email.pwd"));
}

Reference : how to read value from application.properties in spring boot

The definitive guide to form-based website authentication

I would like to add one very important comment: -

  • "In a corporate, intra- net setting," most if not all of the foregoing might not apply!

Many corporations deploy "internal use only" websites which are, effectively, "corporate applications" that happen to have been implemented through URLs. These URLs can (supposedly ...) only be resolved within "the company's internal network." (Which network magically includes all VPN-connected 'road warriors.')

When a user is dutifully-connected to the aforesaid network, their identity ("authentication") is [already ...] "conclusively known," as is their permission ("authorization") to do certain things ... such as ... "to access this website."

This "authentication + authorization" service can be provided by several different technologies, such as LDAP (Microsoft OpenDirectory), or Kerberos.

From your point-of-view, you simply know this: that anyone who legitimately winds-up at your website must be accompanied by [an environment-variable magically containing ...] a "token." (i.e. The absence of such a token must be immediate grounds for 404 Not Found.)

The token's value makes no sense to you, but, should the need arise, "appropriate means exist" by which your website can "[authoritatively] ask someone who knows (LDAP... etc.)" about any and every(!) question that you may have. In other words, you do not avail yourself of any "home-grown logic." Instead, you inquire of The Authority and implicitly trust its verdict.

Uh huh ... it's quite a mental-switch from the "wild-and-wooly Internet."

How can I easily convert DataReader to List<T>?

I would suggest writing an extension method for this:

public static IEnumerable<T> Select<T>(this IDataReader reader,
                                       Func<IDataReader, T> projection)
{
    while (reader.Read())
    {
        yield return projection(reader);
    }
}

You can then use LINQ's ToList() method to convert that into a List<T> if you want, like this:

using (IDataReader reader = ...)
{
    List<Customer> customers = reader.Select(r => new Customer {
        CustomerId = r["id"] is DBNull ? null : r["id"].ToString(),
        CustomerName = r["name"] is DBNull ? null : r["name"].ToString() 
    }).ToList();
}

I would actually suggest putting a FromDataReader method in Customer (or somewhere else):

public static Customer FromDataReader(IDataReader reader) { ... }

That would leave:

using (IDataReader reader = ...)
{
    List<Customer> customers = reader.Select<Customer>(Customer.FromDataReader)
                                     .ToList();
}

(I don't think type inference would work in this case, but I could be wrong...)

When to use .First and when to use .FirstOrDefault with LINQ?

First()

When you know that result contain more than 1 element expected and you should only the first element of sequence.

FirstOrDefault()

FirstOrDefault() is just like First() except that, if no element match the specified condition than it returns default value of underlying type of generic collection. It does not throw InvalidOperationException if no element found. But collection of element or a sequence is null than it throws an exception.

How to validate an OAuth 2.0 access token for a resource server?

OAuth v2 specs indicates:

Access token attributes and the methods used to access protected resources are beyond the scope of this specification and are defined by companion specifications.

My Authorisation Server has a webservice (SOAP) endpoint that allows the Resource Server to know whether the access_token is valid.

Get GPS location via a service in Android

ok , i've solved it by creating a handler on the onCreate of the service , and calling the gps functions through there .

The code is as simple as this:

final handler=new Handler(Looper.getMainLooper()); 

And then to force running things on the UI, I call post on it.

Using GCC to produce readable assembly?

If you give GCC the flag -fverbose-asm, it will

Put extra commentary information in the generated assembly code to make it more readable.

[...] The added comments include:

  • information on the compiler version and command-line options,
  • the source code lines associated with the assembly instructions, in the form FILENAME:LINENUMBER:CONTENT OF LINE,
  • hints on which high-level expressions correspond to the various assembly instruction operands.

How do I get PHP errors to display?

Report all errors except E_NOTICE

error_reporting(E_ALL & ~E_NOTICE);

Display all PHP errors

error_reporting(E_ALL);  or ini_set('error_reporting', E_ALL);

Turn off all error reporting

error_reporting(0);

Defining Z order of views of RelativeLayout in Android

I encountered the same issues: In a relative layout parentView, I have 2 children childView1 and childView2. At first, I put childView1 above childView2 and I want childView1 to be on top of childView2. Changing the order of children views did not solve the problem for me. What worked for me is to set android:clipChildren="false" on parentView and in the code I set:

childView1.bringToFront();

parentView.invalidate();

Download file from an ASP.NET Web API method using AngularJS

In your component i.e angular js code:

function getthefile (){
window.location.href='http://localhost:1036/CourseRegConfirm/getfile';
};

bootstrap 4 row height

Use the sizing utility classes...

  • h-50 = height 50%
  • h-100 = height 100%

http://www.codeply.com/go/Y3nG0io2uE

 <div class="container">
        <div class="row">
            <div class="col-md-8 col-lg-6 B">
                <div class="card card-inverse card-primary">
                    <img src="http://lorempicsum.com/rio/800/500/4" class="img-fluid" alt="Responsive image">
                </div>
            </div>
            <div class="col-md-4 col-lg-3 G">
                <div class="row h-100">
                    <div class="col-md-6 col-lg-6 B h-50 pb-3">
                        <div class="card card-inverse card-success h-100">

                        </div>
                    </div>
                    <div class="col-md-6 col-lg-6 B h-50 pb-3">
                        <div class="card card-inverse bg-success h-100">

                        </div>
                    </div>
                    <div class="col-md-12 h-50">
                        <div class="card card-inverse bg-danger h-100">

                        </div>
                    </div>
                </div>
            </div>
        </div>
    </div>

Or, for an unknown number of child columns, use flexbox and the cols will fill height. See the d-flex flex-column on the row, and h-100 on the child cols.

<div class="container">
    <div class="row">
        <div class="col-md-8 col-lg-6 B">
            <div class="card card-inverse card-primary">
                <img src="http://lorempicsum.com/rio/800/500/4" class="img-fluid" alt="Responsive image">
            </div>
        </div>
        <div class="col-md-4 col-lg-3 G ">
            <div class="row d-flex flex-column h-100">
                <div class="col-md-6 col-lg-6 B h-100">
                    <div class="card bg-success h-100">

                    </div>
                </div>
                <div class="col-md-6 col-lg-6 B h-100">
                    <div class="card bg-success h-100">

                    </div>
                </div>
                <div class="col-md-12 h-100">
                    <div class="card bg-danger h-100">

                    </div>
                </div>
            </div>
        </div>
    </div>
</div>

https://www.codeply.com/go/tgzFAH8vaW

Android Calling JavaScript functions in WebView

From kitkat onwards use evaluateJavascript method instead loadUrl to call the javascript functions like below

    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT) {
        webView.evaluateJavascript("enable();", null);
    } else {
        webView.loadUrl("javascript:enable();");
    }

How to normalize a vector in MATLAB efficiently? Any related built-in function?

Fastest by far (time is in comparison to Jacobs):

clc; clear all;
V = rand(1024*1024*32,1);
N = 10;
tic; 
for i=1:N, 
    d = 1/sqrt(V(1)*V(1)+V(2)*V(2)+V(3)*V(3)); 
    V1 = V*d;
end; 
toc % 1.5s

Resource files not found from JUnit test cases

Main classes should be under src/main/java
and
test classes should be under src/test/java

If all in the correct places and still main classes are not accessible then
Right click project => Maven => Update Project
Hope so this will resolve the issue

What's the best practice to round a float to 2 decimals?

Here is a shorter implementation comparing to @Jav_Rock's

   /**
     * Round to certain number of decimals
     * 
     * @param d
     * @param decimalPlace the numbers of decimals
     * @return
     */

    public static float round(float d, int decimalPlace) {
         return BigDecimal.valueOf(d).setScale(decimalPlace,BigDecimal.ROUND_HALF_UP).floatValue();
    }



    System.out.println(round(2.345f,2));//two decimal digits, //2.35

Removing the first 3 characters from a string

Use the substring method of the String class :

String removeCurrency=amount.getText().toString().substring(3);

Pass Multiple Parameters to jQuery ajax call

    var valueOfTextBox=$("#result").val();
    var valueOfSelectedCheckbox=$("#radio:checked").val();

    $.ajax({
    url: 'result.php',
    type: 'POST',
    data: { forValue: valueOfTextBox, check : valueOfSelectedCheckbox } ,
    beforeSend: function() {

          $("#loader").show();
       },
    success: function (response) {
       $("#loader").hide();
       $("#answer").text(response);
    },
    error: function () {
        //$("#loader").show();
        alert("error occured");
    }
    }); 

Using union and order by clause in mysql

This is because You're sorting entire result-set, You should sort, every part of union separately, or You can use ORDER BY (Something ie. subquery distance) THEN (something ie row id) clause

java.util.zip.ZipException: error in opening zip file

In my case SL4j-api.jar with multiple versions are conflicting in the maven repo. Than I deleted the entire SL4j-api folder in m2 maven repo and updated maven project, build maven project than ran the project in JBOSS server. issue got resolved.

Is there a way to detect if an image is blurry?

During some work with an auto-focus lens, I came across this very useful set of algorithms for detecting image focus. It's implemented in MATLAB, but most of the functions are quite easy to port to OpenCV with filter2D.

It's basically a survey implementation of many focus measurement algorithms. If you want to read the original papers, references to the authors of the algorithms are provided in the code. The 2012 paper by Pertuz, et al. Analysis of focus measure operators for shape from focus (SFF) gives a great review of all of these measure as well as their performance (both in terms of speed and accuracy as applied to SFF).

EDIT: Added MATLAB code just in case the link dies.

function FM = fmeasure(Image, Measure, ROI)
%This function measures the relative degree of focus of 
%an image. It may be invoked as:
%
%   FM = fmeasure(Image, Method, ROI)
%
%Where 
%   Image,  is a grayscale image and FM is the computed
%           focus value.
%   Method, is the focus measure algorithm as a string.
%           see 'operators.txt' for a list of focus 
%           measure methods. 
%   ROI,    Image ROI as a rectangle [xo yo width heigth].
%           if an empty argument is passed, the whole
%           image is processed.
%
%  Said Pertuz
%  Abr/2010


if ~isempty(ROI)
    Image = imcrop(Image, ROI);
end

WSize = 15; % Size of local window (only some operators)

switch upper(Measure)
    case 'ACMO' % Absolute Central Moment (Shirvaikar2004)
        if ~isinteger(Image), Image = im2uint8(Image);
        end
        FM = AcMomentum(Image);

    case 'BREN' % Brenner's (Santos97)
        [M N] = size(Image);
        DH = Image;
        DV = Image;
        DH(1:M-2,:) = diff(Image,2,1);
        DV(:,1:N-2) = diff(Image,2,2);
        FM = max(DH, DV);        
        FM = FM.^2;
        FM = mean2(FM);

    case 'CONT' % Image contrast (Nanda2001)
        ImContrast = inline('sum(abs(x(:)-x(5)))');
        FM = nlfilter(Image, [3 3], ImContrast);
        FM = mean2(FM);

    case 'CURV' % Image Curvature (Helmli2001)
        if ~isinteger(Image), Image = im2uint8(Image);
        end
        M1 = [-1 0 1;-1 0 1;-1 0 1];
        M2 = [1 0 1;1 0 1;1 0 1];
        P0 = imfilter(Image, M1, 'replicate', 'conv')/6;
        P1 = imfilter(Image, M1', 'replicate', 'conv')/6;
        P2 = 3*imfilter(Image, M2, 'replicate', 'conv')/10 ...
            -imfilter(Image, M2', 'replicate', 'conv')/5;
        P3 = -imfilter(Image, M2, 'replicate', 'conv')/5 ...
            +3*imfilter(Image, M2, 'replicate', 'conv')/10;
        FM = abs(P0) + abs(P1) + abs(P2) + abs(P3);
        FM = mean2(FM);

    case 'DCTE' % DCT energy ratio (Shen2006)
        FM = nlfilter(Image, [8 8], @DctRatio);
        FM = mean2(FM);

    case 'DCTR' % DCT reduced energy ratio (Lee2009)
        FM = nlfilter(Image, [8 8], @ReRatio);
        FM = mean2(FM);

    case 'GDER' % Gaussian derivative (Geusebroek2000)        
        N = floor(WSize/2);
        sig = N/2.5;
        [x,y] = meshgrid(-N:N, -N:N);
        G = exp(-(x.^2+y.^2)/(2*sig^2))/(2*pi*sig);
        Gx = -x.*G/(sig^2);Gx = Gx/sum(Gx(:));
        Gy = -y.*G/(sig^2);Gy = Gy/sum(Gy(:));
        Rx = imfilter(double(Image), Gx, 'conv', 'replicate');
        Ry = imfilter(double(Image), Gy, 'conv', 'replicate');
        FM = Rx.^2+Ry.^2;
        FM = mean2(FM);

    case 'GLVA' % Graylevel variance (Krotkov86)
        FM = std2(Image);

    case 'GLLV' %Graylevel local variance (Pech2000)        
        LVar = stdfilt(Image, ones(WSize,WSize)).^2;
        FM = std2(LVar)^2;

    case 'GLVN' % Normalized GLV (Santos97)
        FM = std2(Image)^2/mean2(Image);

    case 'GRAE' % Energy of gradient (Subbarao92a)
        Ix = Image;
        Iy = Image;
        Iy(1:end-1,:) = diff(Image, 1, 1);
        Ix(:,1:end-1) = diff(Image, 1, 2);
        FM = Ix.^2 + Iy.^2;
        FM = mean2(FM);

    case 'GRAT' % Thresholded gradient (Snatos97)
        Th = 0; %Threshold
        Ix = Image;
        Iy = Image;
        Iy(1:end-1,:) = diff(Image, 1, 1);
        Ix(:,1:end-1) = diff(Image, 1, 2);
        FM = max(abs(Ix), abs(Iy));
        FM(FM<Th)=0;
        FM = sum(FM(:))/sum(sum(FM~=0));

    case 'GRAS' % Squared gradient (Eskicioglu95)
        Ix = diff(Image, 1, 2);
        FM = Ix.^2;
        FM = mean2(FM);

    case 'HELM' %Helmli's mean method (Helmli2001)        
        MEANF = fspecial('average',[WSize WSize]);
        U = imfilter(Image, MEANF, 'replicate');
        R1 = U./Image;
        R1(Image==0)=1;
        index = (U>Image);
        FM = 1./R1;
        FM(index) = R1(index);
        FM = mean2(FM);

    case 'HISE' % Histogram entropy (Krotkov86)
        FM = entropy(Image);

    case 'HISR' % Histogram range (Firestone91)
        FM = max(Image(:))-min(Image(:));


    case 'LAPE' % Energy of laplacian (Subbarao92a)
        LAP = fspecial('laplacian');
        FM = imfilter(Image, LAP, 'replicate', 'conv');
        FM = mean2(FM.^2);

    case 'LAPM' % Modified Laplacian (Nayar89)
        M = [-1 2 -1];        
        Lx = imfilter(Image, M, 'replicate', 'conv');
        Ly = imfilter(Image, M', 'replicate', 'conv');
        FM = abs(Lx) + abs(Ly);
        FM = mean2(FM);

    case 'LAPV' % Variance of laplacian (Pech2000)
        LAP = fspecial('laplacian');
        ILAP = imfilter(Image, LAP, 'replicate', 'conv');
        FM = std2(ILAP)^2;

    case 'LAPD' % Diagonal laplacian (Thelen2009)
        M1 = [-1 2 -1];
        M2 = [0 0 -1;0 2 0;-1 0 0]/sqrt(2);
        M3 = [-1 0 0;0 2 0;0 0 -1]/sqrt(2);
        F1 = imfilter(Image, M1, 'replicate', 'conv');
        F2 = imfilter(Image, M2, 'replicate', 'conv');
        F3 = imfilter(Image, M3, 'replicate', 'conv');
        F4 = imfilter(Image, M1', 'replicate', 'conv');
        FM = abs(F1) + abs(F2) + abs(F3) + abs(F4);
        FM = mean2(FM);

    case 'SFIL' %Steerable filters (Minhas2009)
        % Angles = [0 45 90 135 180 225 270 315];
        N = floor(WSize/2);
        sig = N/2.5;
        [x,y] = meshgrid(-N:N, -N:N);
        G = exp(-(x.^2+y.^2)/(2*sig^2))/(2*pi*sig);
        Gx = -x.*G/(sig^2);Gx = Gx/sum(Gx(:));
        Gy = -y.*G/(sig^2);Gy = Gy/sum(Gy(:));
        R(:,:,1) = imfilter(double(Image), Gx, 'conv', 'replicate');
        R(:,:,2) = imfilter(double(Image), Gy, 'conv', 'replicate');
        R(:,:,3) = cosd(45)*R(:,:,1)+sind(45)*R(:,:,2);
        R(:,:,4) = cosd(135)*R(:,:,1)+sind(135)*R(:,:,2);
        R(:,:,5) = cosd(180)*R(:,:,1)+sind(180)*R(:,:,2);
        R(:,:,6) = cosd(225)*R(:,:,1)+sind(225)*R(:,:,2);
        R(:,:,7) = cosd(270)*R(:,:,1)+sind(270)*R(:,:,2);
        R(:,:,7) = cosd(315)*R(:,:,1)+sind(315)*R(:,:,2);
        FM = max(R,[],3);
        FM = mean2(FM);

    case 'SFRQ' % Spatial frequency (Eskicioglu95)
        Ix = Image;
        Iy = Image;
        Ix(:,1:end-1) = diff(Image, 1, 2);
        Iy(1:end-1,:) = diff(Image, 1, 1);
        FM = mean2(sqrt(double(Iy.^2+Ix.^2)));

    case 'TENG'% Tenengrad (Krotkov86)
        Sx = fspecial('sobel');
        Gx = imfilter(double(Image), Sx, 'replicate', 'conv');
        Gy = imfilter(double(Image), Sx', 'replicate', 'conv');
        FM = Gx.^2 + Gy.^2;
        FM = mean2(FM);

    case 'TENV' % Tenengrad variance (Pech2000)
        Sx = fspecial('sobel');
        Gx = imfilter(double(Image), Sx, 'replicate', 'conv');
        Gy = imfilter(double(Image), Sx', 'replicate', 'conv');
        G = Gx.^2 + Gy.^2;
        FM = std2(G)^2;

    case 'VOLA' % Vollath's correlation (Santos97)
        Image = double(Image);
        I1 = Image; I1(1:end-1,:) = Image(2:end,:);
        I2 = Image; I2(1:end-2,:) = Image(3:end,:);
        Image = Image.*(I1-I2);
        FM = mean2(Image);

    case 'WAVS' %Sum of Wavelet coeffs (Yang2003)
        [C,S] = wavedec2(Image, 1, 'db6');
        H = wrcoef2('h', C, S, 'db6', 1);   
        V = wrcoef2('v', C, S, 'db6', 1);   
        D = wrcoef2('d', C, S, 'db6', 1);   
        FM = abs(H) + abs(V) + abs(D);
        FM = mean2(FM);

    case 'WAVV' %Variance of  Wav...(Yang2003)
        [C,S] = wavedec2(Image, 1, 'db6');
        H = abs(wrcoef2('h', C, S, 'db6', 1));
        V = abs(wrcoef2('v', C, S, 'db6', 1));
        D = abs(wrcoef2('d', C, S, 'db6', 1));
        FM = std2(H)^2+std2(V)+std2(D);

    case 'WAVR'
        [C,S] = wavedec2(Image, 3, 'db6');
        H = abs(wrcoef2('h', C, S, 'db6', 1));   
        V = abs(wrcoef2('v', C, S, 'db6', 1));   
        D = abs(wrcoef2('d', C, S, 'db6', 1)); 
        A1 = abs(wrcoef2('a', C, S, 'db6', 1));
        A2 = abs(wrcoef2('a', C, S, 'db6', 2));
        A3 = abs(wrcoef2('a', C, S, 'db6', 3));
        A = A1 + A2 + A3;
        WH = H.^2 + V.^2 + D.^2;
        WH = mean2(WH);
        WL = mean2(A);
        FM = WH/WL;
    otherwise
        error('Unknown measure %s',upper(Measure))
end
 end
%************************************************************************
function fm = AcMomentum(Image)
[M N] = size(Image);
Hist = imhist(Image)/(M*N);
Hist = abs((0:255)-255*mean2(Image))'.*Hist;
fm = sum(Hist);
end

%******************************************************************
function fm = DctRatio(M)
MT = dct2(M).^2;
fm = (sum(MT(:))-MT(1,1))/MT(1,1);
end

%************************************************************************
function fm = ReRatio(M)
M = dct2(M);
fm = (M(1,2)^2+M(1,3)^2+M(2,1)^2+M(2,2)^2+M(3,1)^2)/(M(1,1)^2);
end
%******************************************************************

A few examples of OpenCV versions:

// OpenCV port of 'LAPM' algorithm (Nayar89)
double modifiedLaplacian(const cv::Mat& src)
{
    cv::Mat M = (Mat_<double>(3, 1) << -1, 2, -1);
    cv::Mat G = cv::getGaussianKernel(3, -1, CV_64F);

    cv::Mat Lx;
    cv::sepFilter2D(src, Lx, CV_64F, M, G);

    cv::Mat Ly;
    cv::sepFilter2D(src, Ly, CV_64F, G, M);

    cv::Mat FM = cv::abs(Lx) + cv::abs(Ly);

    double focusMeasure = cv::mean(FM).val[0];
    return focusMeasure;
}

// OpenCV port of 'LAPV' algorithm (Pech2000)
double varianceOfLaplacian(const cv::Mat& src)
{
    cv::Mat lap;
    cv::Laplacian(src, lap, CV_64F);

    cv::Scalar mu, sigma;
    cv::meanStdDev(lap, mu, sigma);

    double focusMeasure = sigma.val[0]*sigma.val[0];
    return focusMeasure;
}

// OpenCV port of 'TENG' algorithm (Krotkov86)
double tenengrad(const cv::Mat& src, int ksize)
{
    cv::Mat Gx, Gy;
    cv::Sobel(src, Gx, CV_64F, 1, 0, ksize);
    cv::Sobel(src, Gy, CV_64F, 0, 1, ksize);

    cv::Mat FM = Gx.mul(Gx) + Gy.mul(Gy);

    double focusMeasure = cv::mean(FM).val[0];
    return focusMeasure;
}

// OpenCV port of 'GLVN' algorithm (Santos97)
double normalizedGraylevelVariance(const cv::Mat& src)
{
    cv::Scalar mu, sigma;
    cv::meanStdDev(src, mu, sigma);

    double focusMeasure = (sigma.val[0]*sigma.val[0]) / mu.val[0];
    return focusMeasure;
}

No guarantees on whether or not these measures are the best choice for your problem, but if you track down the papers associated with these measures, they may give you more insight. Hope you find the code useful! I know I did.

MySQL GROUP BY two columns

First, let's make some test data:

create table client (client_id integer not null primary key auto_increment,
                     name varchar(64));
create table portfolio (portfolio_id integer not null primary key auto_increment,
                        client_id integer references client.id,
                        cash decimal(10,2),
                        stocks decimal(10,2));
insert into client (name) values ('John Doe'), ('Jane Doe');
insert into portfolio (client_id, cash, stocks) values (1, 11.11, 22.22),
                                                       (1, 10.11, 23.22),
                                                       (2, 30.30, 40.40),
                                                       (2, 40.40, 50.50);

If you didn't need the portfolio ID, it would be easy:

select client_id, name, max(cash + stocks)
from client join portfolio using (client_id)
group by client_id

+-----------+----------+--------------------+
| client_id | name     | max(cash + stocks) |
+-----------+----------+--------------------+
|         1 | John Doe |              33.33 | 
|         2 | Jane Doe |              90.90 | 
+-----------+----------+--------------------+

Since you need the portfolio ID, things get more complicated. Let's do it in steps. First, we'll write a subquery that returns the maximal portfolio value for each client:

select client_id, max(cash + stocks) as maxtotal
from portfolio
group by client_id

+-----------+----------+
| client_id | maxtotal |
+-----------+----------+
|         1 |    33.33 | 
|         2 |    90.90 | 
+-----------+----------+

Then we'll query the portfolio table, but use a join to the previous subquery in order to keep only those portfolios the total value of which is the maximal for the client:

 select portfolio_id, cash + stocks from portfolio 
 join (select client_id, max(cash + stocks) as maxtotal 
       from portfolio
       group by client_id) as maxima
 using (client_id)
 where cash + stocks = maxtotal

+--------------+---------------+
| portfolio_id | cash + stocks |
+--------------+---------------+
|            5 |         33.33 | 
|            6 |         33.33 | 
|            8 |         90.90 | 
+--------------+---------------+

Finally, we can join to the client table (as you did) in order to include the name of each client:

select client_id, name, portfolio_id, cash + stocks
from client
join portfolio using (client_id)
join (select client_id, max(cash + stocks) as maxtotal
      from portfolio 
      group by client_id) as maxima
using (client_id)
where cash + stocks = maxtotal

+-----------+----------+--------------+---------------+
| client_id | name     | portfolio_id | cash + stocks |
+-----------+----------+--------------+---------------+
|         1 | John Doe |            5 |         33.33 | 
|         1 | John Doe |            6 |         33.33 | 
|         2 | Jane Doe |            8 |         90.90 | 
+-----------+----------+--------------+---------------+

Note that this returns two rows for John Doe because he has two portfolios with the exact same total value. To avoid this and pick an arbitrary top portfolio, tag on a GROUP BY clause:

select client_id, name, portfolio_id, cash + stocks
from client
join portfolio using (client_id)
join (select client_id, max(cash + stocks) as maxtotal
      from portfolio 
      group by client_id) as maxima
using (client_id)
where cash + stocks = maxtotal
group by client_id, cash + stocks

+-----------+----------+--------------+---------------+
| client_id | name     | portfolio_id | cash + stocks |
+-----------+----------+--------------+---------------+
|         1 | John Doe |            5 |         33.33 | 
|         2 | Jane Doe |            8 |         90.90 | 
+-----------+----------+--------------+---------------+

What's the difference between git reset --mixed, --soft, and --hard?

In the simplest terms:

  • --soft: uncommit changes, changes are left staged (index).
  • --mixed (default): uncommit + unstage changes, changes are left in working tree.
  • --hard: uncommit + unstage + delete changes, nothing left.

How to share data between different threads In C# using AOP?

Look at the following example code:

public class MyWorker
{
    public SharedData state;
    public void DoWork(SharedData someData)
    {
        this.state = someData;
        while (true) ;
    }

}

public class SharedData {
    X myX;
    public getX() { etc
    public setX(anX) { etc

}

public class Program
{
    public static void Main()
    {
        SharedData data = new SharedDate()
        MyWorker work1 = new MyWorker(data);
        MyWorker work2 = new MyWorker(data);
        Thread thread = new Thread(new ThreadStart(work1.DoWork));
        thread.Start();
        Thread thread2 = new Thread(new ThreadStart(work2.DoWork));
        thread2.Start();
    }
}

In this case, the thread class MyWorker has a variable state. We initialise it with the same object. Now you can see that the two workers access the same SharedData object. Changes made by one worker are visible to the other.

You have quite a few remaining issues. How does worker 2 know when changes have been made by worker 1 and vice-versa? How do you prevent conflicting changes? Maybe read: this tutorial.

Is there a command to refresh environment variables from the command prompt in Windows?

I came across this answer before eventually finding an easier solution.

Simply restart explorer.exe in Task Manager.

I didn't test, but you may also need to reopen you command prompt.

Credit to Timo Huovinen here: Node not recognized although successfully installed (if this helped you, please go give this man's comment credit).

iOS 7.0 No code signing identities found

I just had this problem with Jenkins.

The solution was to copy the certificate and paste it into the system keychain otherwise Jenkins couldn't read the certificate.

PermissionError: [Errno 13] Permission denied

This also happens if you are trying to write a file, but your path is a folder.

This can happen easily by mistake.

To defend against that, use:

import os

path = r"my/path/to/file.txt"
assert os.path.isfile(path)
with open(path, "r") as f:
    pass

The assertion will fail if your path is actually a folder.

Insert images to XML file

XML is not a format for storing images, neither binary data. I think it all depends on how you want to use those images. If you are in a web application and would want to read them from there and display them, I would store the URLs. If you need to send them to another web endpoint, I would serialize them, rather than persisting manually in XML. Please explain what is the scenario.

Could not load file or assembly 'Microsoft.Web.Infrastructure,

It turns out after doing a Reference Cleaning, it removed Microsoft.Web.Infrastructure, but not from the packages.config file. After trying to add it again using the Package Manager Console, Visual Studio says that it is already installed which is false because it was removed.

I then removed the line of code in the packages.config file

<package id="Microsoft.Web.Infrastructure" version="1.0.0.0" targetFramework="net45" />

and ran the command again

PM> Install-Package Microsoft.Web.Infrastructure

After this, now it works fine.

Access-control-allow-origin with multiple domains

There can only be one Access-Control-Allow-Origin response header, and that header can only have one origin value. Therefore, in order to get this to work, you need to have some code that:

  1. Grabs the Origin request header.
  2. Checks if the origin value is one of the whitelisted values.
  3. If it is valid, sets the Access-Control-Allow-Origin header with that value.

I don't think there's any way to do this solely through the web.config.

if (ValidateRequest()) {
    Response.Headers.Remove("Access-Control-Allow-Origin");
    Response.AddHeader("Access-Control-Allow-Origin", Request.UrlReferrer.GetLeftPart(UriPartial.Authority));

    Response.Headers.Remove("Access-Control-Allow-Credentials");
    Response.AddHeader("Access-Control-Allow-Credentials", "true");

    Response.Headers.Remove("Access-Control-Allow-Methods");
    Response.AddHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS");
}

How do I get the current location of an iframe?

You can use Ra-Ajax and have an iframe wrapped inside e.g. a Window control. Though in general terms I don't encourage people to use iframes (for anything)

Another alternative is to load the HTML on the server and send it directly into the Window as the content of a Label or something. Check out how this Ajax RSS parser is loading the RSS items in the source which can be downloaded here (Open Source - LGPL)

(Disclaimer; I work with Ra-Ajax...)

Difference of keywords 'typename' and 'class' in templates?

This piece of snippet is from c++ primer book. Although I am sure this is wrong.

Each type parameter must be preceded by the keyword class or typename:

// error: must precede U with either typename or class
template <typename T, U> T calc(const T&, const U&);

These keywords have the same meaning and can be used interchangeably inside a template parameter list. A template parameter list can use both keywords:

// ok: no distinction between typename and class in a template parameter list
template <typename T, class U> calc (const T&, const U&);

It may seem more intuitive to use the keyword typename rather than class to designate a template type parameter. After all, we can use built-in (nonclass) types as a template type argument. Moreover, typename more clearly indicates that the name that follows is a type name. However, typename was added to C++ after templates were already in widespread use; some programmers continue to use class exclusively

How to center a label text in WPF?

Sample:

Label label = new Label();
label.HorizontalContentAlignment = HorizontalAlignment.Center;

Vue.js—Difference between v-model and v-bind

v-model is for two way bindings means: if you change input value, the bound data will be changed and vice versa. But v-bind:value is called one way binding that means: you can change input value by changing bound data but you can't change bound data by changing input value through the element.

v-model is intended to be used with form elements. It allows you to tie the form element (e.g. a text input) with the data object in your Vue instance.

Example: https://jsfiddle.net/jamesbrndwgn/j2yb9zt1/1/

v-bind is intended to be used with components to create custom props. This allows you to pass data to a component. As the prop is reactive, if the data that’s passed to the component changes then the component will reflect this change

Example: https://jsfiddle.net/jamesbrndwgn/ws5kad1c/3/

Hope this helps you with basic understanding.

Check orientation on Android phone

A fully way to specify the current orientation of the phone:

public String getRotation(Context context) {
    final int rotation = ((WindowManager) context.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay().getOrientation();
    switch (rotation) {
        case Surface.ROTATION_0:
            return "portrait";
        case Surface.ROTATION_90:
            return "landscape";
        case Surface.ROTATION_180:
            return "reverse portrait";
        default:
            return "reverse landscape";
    }
}

When and how should I use a ThreadLocal variable?

ThreadLocal is a specially provisioned functionality by JVM to provide an isolated storage space for threads only. like the value of instance scoped variable are bound to a given instance of a class only. each object has its only values and they can not see each other value. so is the concept of ThreadLocal variables, they are local to the thread in the sense of object instances other thread except for the one which created it, can not see it. See Here

import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.IntStream;


public class ThreadId {
private static final AtomicInteger nextId = new AtomicInteger(1000);

// Thread local variable containing each thread's ID
private static final ThreadLocal<Integer> threadId = ThreadLocal.withInitial(() -> nextId.getAndIncrement());


// Returns the current thread's unique ID, assigning it if necessary
public static int get() {
    return threadId.get();
}

public static void main(String[] args) {

    new Thread(() -> IntStream.range(1, 3).forEach(i -> {
        System.out.println(Thread.currentThread().getName() + " >> " + new ThreadId().get());
    })).start();

    new Thread(() -> IntStream.range(1, 3).forEach(i -> {
        System.out.println(Thread.currentThread().getName() + " >> " + new ThreadId().get());
    })).start();

    new Thread(() -> IntStream.range(1, 3).forEach(i -> {
        System.out.println(Thread.currentThread().getName() + " >> " + new ThreadId().get());
    })).start();

}
}

Exposing a port on a live Docker container

While you cannot expose a new port of an existing container, you can start a new container in the same Docker network and get it to forward traffic to the original container.

# docker run \
  --rm \
  -p $PORT:1234 \
  verb/socat \
    TCP-LISTEN:1234,fork \
    TCP-CONNECT:$TARGET_CONTAINER_IP:$TARGET_CONTAINER_PORT

Worked Example

Launch a web-service that listens on port 80, but do not expose its internal port 80 (oops!):

# docker run -ti mkodockx/docker-pastebin   # Forgot to expose PORT 80!

Find its Docker network IP:

# docker inspect 63256f72142a | grep IPAddress
                    "IPAddress": "172.17.0.2",

Launch verb/socat with port 8080 exposed, and get it to forward TCP traffic to that IP's port 80:

# docker run --rm -p 8080:1234 verb/socat TCP-LISTEN:1234,fork TCP-CONNECT:172.17.0.2:80

You can now access pastebin on http://localhost:8080/, and your requests goes to socat:1234 which forwards it to pastebin:80, and the response travels the same path in reverse.

The pipe ' ' could not be found angular2 custom pipe

If you see this error when running tests, make sure you have imported the module the pipe belongs to, e.g.:

    beforeEach(async(() => {
        TestBed.configureTestingModule({
            imports: [CustomPipeModule],
            declarations: [...],
            providers: [...],
            ...
        }).compileComponents();
    }));

Facebook development in localhost

It's easy go to the app dashboard under the facebook login tab click settings then select Enforce HTTPs No, save settingsenter image description here

Java: How to convert a File object to a String object in java?

Why you just not read the File line by line and add it to a StringBuffer?

After you reach end of File you can get the String from the StringBuffer.

What does a "Cannot find symbol" or "Cannot resolve symbol" error mean?

SOLVED

Using IntelliJ

Select Build->Rebuild Project will solve it

Get property value from string using reflection

 public static object GetPropValue(object src, string propName)
 {
     return src.GetType().GetProperty(propName).GetValue(src, null);
 }

Of course, you will want to add validation and whatnot, but that is the gist of it.

Animation CSS3: display + opacity

If you are triggering the change with JS, let's say on click, there is a nice workaround.

You see, the problem happens because the animation is ignored on display:none element but browser applies all the changes at once and the element is never display:block while not animated at the same time.

The trick is to ask the browser to render the frame after changing the visibility but before triggering the animation.

Here is a JQuery example:

    $('.child').css({"display":"block"});
    //now ask the browser what is the value of the display property
    $('.child').css("display"); //this will trigger the browser to apply the change. this costs one frame render
    //now a change to opacity will trigger the animation
    $('.child').css("opacity":100);

Getting individual colors from a color map in matplotlib

To build on the solutions from Ffisegydd and amaliammr, here's an example where we make CSV representation for a custom colormap:

#! /usr/bin/env python3
import matplotlib
import numpy as np 

vmin = 0.1
vmax = 1000

norm = matplotlib.colors.Normalize(np.log10(vmin), np.log10(vmax))
lognum = norm(np.log10([.5, 2., 10, 40, 150,1000]))

cdict = {
    'red':
    (
        (0., 0, 0),
        (lognum[0], 0, 0),
        (lognum[1], 0, 0),
        (lognum[2], 1, 1),
        (lognum[3], 0.8, 0.8),
        (lognum[4], .7, .7),
    (lognum[5], .7, .7)
    ),
    'green':
    (
        (0., .6, .6),
        (lognum[0], 0.8, 0.8),
        (lognum[1], 1, 1),
        (lognum[2], 1, 1),
        (lognum[3], 0, 0),
        (lognum[4], 0, 0),
    (lognum[5], 0, 0)
    ),
    'blue':
    (
        (0., 0, 0),
        (lognum[0], 0, 0),
        (lognum[1], 0, 0),
        (lognum[2], 0, 0),
        (lognum[3], 0, 0),
        (lognum[4], 0, 0),
    (lognum[5], 1, 1)
    )
}


mycmap = matplotlib.colors.LinearSegmentedColormap('my_colormap', cdict, 256)   
norm = matplotlib.colors.LogNorm(vmin, vmax)
colors = {}
count = 0
step_size = 0.001
for value in np.arange(vmin, vmax+step_size, step_size):
    count += 1
    print("%d/%d %f%%" % (count, vmax*(1./step_size), 100.*count/(vmax*(1./step_size))))
    rgba = mycmap(norm(value), bytes=True)
    color = (rgba[0], rgba[1], rgba[2])
    if color not in colors.values():
        colors[value] = color

print ("value, red, green, blue")
for value in sorted(colors.keys()):
    rgb = colors[value]
    print("%s, %s, %s, %s" % (value, rgb[0], rgb[1], rgb[2]))

Multi column forms with fieldsets

There are a couple of things that need to be adjusted in your layout:

  1. You are nesting col elements within form-group elements. This should be the other way around (the form-group should be within the col-sm-xx element).

  2. You should always use a row div for each new "row" in your design. In your case, you would need at least 5 rows (Username, Password and co, Title/First/Last name, email, Language). Otherwise, your problematic .col-sm-12 is still on the same row with the above 3 .col-sm-4 resulting in a total of columns greater than 12, and causing the overlap problem.

Here is a fixed demo.

And an excerpt of what the problematic section HTML should become:

<fieldset>
    <legend>Personal Information</legend>
    <div class='row'>
        <div class='col-sm-4'>    
            <div class='form-group'>
                <label for="user_title">Title</label>
                <input class="form-control" id="user_title" name="user[title]" size="30" type="text" />
            </div>
        </div>
        <div class='col-sm-4'>
            <div class='form-group'>
                <label for="user_firstname">First name</label>
                <input class="form-control" id="user_firstname" name="user[firstname]" required="true" size="30" type="text" />
            </div>
        </div>
        <div class='col-sm-4'>
            <div class='form-group'>
                <label for="user_lastname">Last name</label>
                <input class="form-control" id="user_lastname" name="user[lastname]" required="true" size="30" type="text" />
            </div>
        </div>
    </div>
    <div class='row'>
        <div class='col-sm-12'>
            <div class='form-group'>

                <label for="user_email">Email</label>
                <input class="form-control required email" id="user_email" name="user[email]" required="true" size="30" type="text" />
            </div>
        </div>
    </div>
</fieldset>

Create a jTDS connection string

jdbc:jtds:sqlserver://x.x.x.x/database replacing x.x.x.x with the IP or hostname of your SQL Server machine.

jdbc:jtds:sqlserver://MYPC/Blog;instance=SQLEXPRESS

or

jdbc:jtds:sqlserver://MYPC:1433/Blog;instance=SQLEXPRESS

If you are wanting to set the username and password in the connection string too instead of against a connection object separately:

jdbc:jtds:sqlserver://MYPC/Blog;instance=SQLEXPRESS;user=foo;password=bar

(Updated my incorrect information and add reference to the instance syntax)

Export table from database to csv file

rsubmit;
options missing=0;
ods listing close;
ods csv file='\\FILE_PATH_and_Name_of_report.csv';

proc sql;
SELECT *
FROM `YOUR_FINAL_TABLE_NAME';
quit;
ods csv close;

endrsubmit;

Is it safe to delete the "InetPub" folder?

Don't delete the folder or you will create a registry problem. However, if you do not want to use IIS, search the web for turning it off. You might want to check out "www.blackviper.com" because he lists all Operating System "services" (Not "Computer Services" - both are in Administrator Tools) with extra information for what you can and cannot disable to change to manual. If I recall correctly, he had some IIS info and how to turn it off.

Change User Agent in UIWebView

Try this in the AppDelegate.m

+ (void)initialize 

{

    // Set user agent (the only problem is that we can’t modify the User-Agent later in the program)

    // iOS 5.1

    NSDictionary *dictionnary = [[NSDictionary alloc] initWithObjectsAndKeys:@”Mozilla/5.0 (iPad; CPU OS 5_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9B176 Safari/7534.48.3”, @”UserAgent”, nil];


    [[NSUserDefaults standardUserDefaults] registerDefaults:dictionnary];

}

Force IE compatibility mode off using tags

IE8 defaults to standards mode for the intERnet and quirks mode for the intRAnet. The HTML meta tag is ignored if you have the doctype set to xhtml transitional. The solution is to add an HTTP header in code. This worked for us. Now our intranet site is forcing IE8 to render the app in standards mode.

Added to PageInit of the base page class (ASP.net C#):

Response.AddHeader("X-UA-Compatible", "IE=EmulateIE8");

reference: http://ilia.ws/archives/196-IE8-X-UA-Compatible-Rant.html

Passing a varchar full of comma delimited values to a SQL Server IN function

CREATE TABLE t 
  ( 
     id   INT, 
     col1 VARCHAR(50) 
  ) 

INSERT INTO t 
VALUES     (1, 
            'param1') 

INSERT INTO t 
VALUES     (2, 
            'param2') 

INSERT INTO t 
VALUES     (3, 
            'param3') 

INSERT INTO t 
VALUES     (4, 
            'param4') 

INSERT INTO t 
VALUES     (5, 
            'param5') 

DECLARE @params VARCHAR(100) 

SET @params = ',param1,param2,param3,' 

SELECT * 
FROM   t 
WHERE  Charindex(',' + Cast(col1 AS VARCHAR(8000)) + ',', @params) > 0 

working fiddle find here Fiddle

makefile execute another target

If you removed the make all line from your "fresh" target:

fresh :
    rm -f *.o $(EXEC)
    clear

You could simply run the command make fresh all, which will execute as make fresh; make all.

Some might consider this as a second instance of make, but it's certainly not a sub-instance of make (a make inside of a make), which is what your attempt seemed to result in.

Modulo operator in Python

In addition to the other answers, the fmod documentation has some interesting things to say on the subject:

math.fmod(x, y)

Return fmod(x, y), as defined by the platform C library. Note that the Python expression x % y may not return the same result. The intent of the C standard is that fmod(x, y) be exactly (mathematically; to infinite precision) equal to x - n*y for some integer n such that the result has the same sign as x and magnitude less than abs(y). Python’s x % y returns a result with the sign of y instead, and may not be exactly computable for float arguments. For example, fmod(-1e-100, 1e100) is -1e-100, but the result of Python’s -1e-100 % 1e100 is 1e100-1e-100, which cannot be represented exactly as a float, and rounds to the surprising 1e100. For this reason, function fmod() is generally preferred when working with floats, while Python’s x % y is preferred when working with integers.

Executing Javascript code "on the spot" in Chrome?

I'm not sure how far it will get you, but you can execute JavaScript one line at a time from the Developer Tool Console.

python ignore certificate validation urllib2

The easiest way:

python 2

import urllib2, ssl

request = urllib2.Request('https://somedomain.co/')
response = urllib2.urlopen(request, context=ssl._create_unverified_context())

python 3

from urllib.request import urlopen
import ssl

response = urlopen('https://somedomain.co', context=ssl._create_unverified_context())

How to make Git "forget" about a file that was tracked but is now in .gitignore?

  1. Update your .gitignore file – for instance, add a folder you don't want to track to .gitignore.

  2. git rm -r --cached . – Remove all tracked files, including wanted and unwanted. Your code will be safe as long as you have saved locally.

  3. git add . – All files will be added back in, except those in .gitignore.


Hat tip to @AkiraYamamoto for pointing us in the right direction.

Git resolve conflict using --ours/--theirs for all files

function gitcheckoutall() {
    git diff --name-only --diff-filter=U | sed 's/^/"/;s/$/"/' | xargs git checkout --$1
}

I've added this function in .zshrc file.

Use them this way: gitcheckoutall theirs or gitcheckoutall ours

Add Marker function with Google Maps API

You have added the add marker method call outside the function and that causes it to execute before the initialize method which will be called when google maps script loads and thus the marker is not added because map is not initialized Do as below.... Create separate method TestMarker and call it from initialize.

<script type="text/javascript">

    // Standard google maps function
    function initialize() {
        var myLatlng = new google.maps.LatLng(40.779502, -73.967857);
        var myOptions = {
            zoom: 12,
            center: myLatlng,
            mapTypeId: google.maps.MapTypeId.ROADMAP
        }
        map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
        TestMarker();
    }

    // Function for adding a marker to the page.
    function addMarker(location) {
        marker = new google.maps.Marker({
            position: location,
            map: map
        });
    }

    // Testing the addMarker function
    function TestMarker() {
           CentralPark = new google.maps.LatLng(37.7699298, -122.4469157);
           addMarker(CentralPark);
    }
</script>

How to find the number of days between two dates

I would use the DATE_DIFF function to provide this value as below:

SELECT dtCreated
    , bActive
    , dtLastPaymentAttempt
    , dtLastUpdated
    , dtLastVisit
    , DATEDIFF(d, dtLastUpdated, dtCreated) AS Difference
FROM Customers
WHERE (bActive = 'true') 
    AND (dtLastUpdated > CONVERT(DATETIME, '2012-01-0100:00:00', 102))

EDIT: IF using MySQL you omit the 'd' leaving you with

DATEDIFF(dtLastUpdated, dtCreated) AS Difference

How to skip to next iteration in jQuery.each() util?

By 'return non-false', they mean to return any value which would not work out to boolean false. So you could return true, 1, 'non-false', or whatever else you can think up.

JavaScript + Unicode regexes

September 2018 (updated February 2019)

It seems that regexp /\p{L}/u for match letters (as unicode categories)

  • works on Chrome 68.0.3440.106 and Safari 11.1.2 (13605.3.8)
  • NOT working on Firefox 65.0 :(

Here is a working example

_x000D_
_x000D_
In below field you should be able to to type letters but not numbers<br>_x000D_
<input type="text" name="field" onkeydown="return /\p{L}/u.test(event.key)" >
_x000D_
_x000D_
_x000D_

I report this bug here.

Update

After over 2 years according to: 1500035 > 1361876 > 1634135 finally this bug is fixed and will be available in Firefox v.78+

Getting the source of a specific image element with jQuery

var src = $('img.conversation_img[alt="example"]').attr('src');

If you have multiple matching elements only the src of the first one will be returned.

Apply .gitignore on an existing repository already tracking large number of files

Here is one way to “untrack” any files that are would otherwise be ignored under the current set of exclude patterns:

(GIT_INDEX_FILE=some-non-existent-file \
git ls-files --exclude-standard --others --directory --ignored -z) |
xargs -0 git rm --cached -r --ignore-unmatch --

This leaves the files in your working directory but removes them from the index.

The trick used here is to provide a non-existent index file to git ls-files so that it thinks there are no tracked files. The shell code above asks for all the files that would be ignored if the index were empty and then removes them from the actual index with git rm.

After the files have been “untracked”, use git status to verify that nothing important was removed (if so adjust your exclude patterns and use git reset -- path to restore the removed index entry). Then make a new commit that leaves out the “crud”.

The “crud” will still be in any old commits. You can use git filter-branch to produce clean versions of the old commits if you really need a clean history (n.b. using git filter-branch will “rewrite history”, so it should not be undertaken lightly if you have any collaborators that have pulled any of your historical commits after the “crud” was first introduced).

create table with sequence.nextval in oracle

I for myself prefer Lukas Edger's solution.

But you might want to know there is also a function SYS_GUID which can be applied as a default value to a column and generate unique ids.

you can read more about pros and cons here

How do you know if Tomcat Server is installed on your PC

The port 8005 is used as service port. You can send a shutdown command (a configurable password) to that port. It will not "speak" HTTP, so you cannot use your browser to connect.

The default port for delivering web-content is 8080.

But there may be other applications listen to that port. So your tomcat may not start, if the port is not available.

You asked "How do you know, if tomcat server is installed on your PC?". The answer to that question is: You can't

You can't determine, if it is installed, because it may be only extracted from a ZIP archive or packaged within another application (Like JBoss AS (I think)).

Verify External Script Is Loaded

This was very simple now that I realize how to do it, thanks to all the answers for leading me to the solution. I had to abandon $.getScript() in order to specify the source of the script...sometimes doing things manually is best.

Solution

//great suggestion @Jasper
var len = $('script[src*="Javascript/MyScript.js"]').length; 

if (len === 0) {
        alert('script not loaded');

        loadScript('Javascript/MyScript.js');

        if ($('script[src*="Javascript/MyScript.js"]').length === 0) {
            alert('still not loaded');
        }
        else {
            alert('loaded now');
        }
    }
    else {
        alert('script loaded');
    }


function loadScript(scriptLocationAndName) {
    var head = document.getElementsByTagName('head')[0];
    var script = document.createElement('script');
    script.type = 'text/javascript';
    script.src = scriptLocationAndName;
    head.appendChild(script);
}

What is the best way to detect a mobile device?

This seems to be a comprehensive, modern solution:

https://github.com/matthewhudson/device.js

It detects several platforms, smartphone vs. tablets, and orientation. It also adds classes to the BODY tag so detection takes place only once and you can read what device you're on with a simple series of jQuery hasClass functions.

Check it out...

[DISCLAIMER: I've got nothing to do with the person who wrote it.]

Write HTML string in JSON

It is possible to write an HTML string in JSON. You just need to escape your double-quotes.

[
    {
        "id": "services.html",
        "img": "img/SolutionInnerbananer.jpg",
        "html": "<h2class=\"fg-white\">AboutUs</h2><pclass=\"fg-white\">CSMTechnologiesisapioneerinprovidingconsulting,
        developingandsupportingcomplexITsolutions.Touchingmillionsoflivesworldwidebybringingininnovativetechnology,
        CSMforayedintotheuntappedmarketslikee-GovernanceinIndiaandAfricancontinent.</p>"
    }
]

Force index use in Oracle

You can use optimizer hints

select /*+ INDEX(table_name index_name) */ from table etc...

More on using optimizer hints: http://download.oracle.com/docs/cd/B19306_01/server.102/b14211/hintsref.htm

Center image horizontally within a div

Put the picture inside a newDiv. Make the width of the containing div the same as the image. Apply margin: 0 auto; to the newDiv. That should center the div within the container.

Dump all documents of Elasticsearch

Here's a new tool we've been working on for exactly this purpose https://github.com/taskrabbit/elasticsearch-dump. You can export indices into/out of JSON files, or from one cluster to another.

How to vertically align label and input in Bootstrap 3?

I'm sure you've found your answer by now, but for those who are still looking for an answer:

When input-lg is used, margins mismatch unless you use form-group-lg in addition to form-group class. Its example is in docs:

<form class="form-horizontal">
  <div class="form-group form-group-lg">
    <label class="col-sm-2 control-label" for="formGroupInputLarge">Large label</label>
    <div class="col-sm-10">
      <input class="form-control" type="text" id="formGroupInputLarge" placeholder="Large input">
    </div>
  </div>
  <div class="form-group form-group-sm">
    <label class="col-sm-2 control-label" for="formGroupInputSmall">Small label</label>
    <div class="col-sm-10">
      <input class="form-control" type="text" id="formGroupInputSmall" placeholder="Small input">
    </div>
  </div>
</form>

VBScript -- Using error handling

I'm exceptionally new to VBScript, so this may not be considered best practice or there may be a reason it shouldn't be done this that way I'm not yet aware of, but this is the solution I came up with to trim down the amount of error logging code in my main code block.

Dim oConn, connStr
Set oConn = Server.CreateObject("ADODB.Connection")
connStr = "Provider=SQLOLEDB;Server=XX;UID=XX;PWD=XX;Databse=XX"

ON ERROR RESUME NEXT

oConn.Open connStr
If err.Number <> 0 Then : showError() : End If


Sub ShowError()

    'You could write the error details to the console...
    errDetail = "<script>" & _
    "console.log('Description: " & err.Description & "');" & _
    "console.log('Error number: " & err.Number & "');" & _
    "console.log('Error source: " & err.Source & "');" & _
    "</script>"

    Response.Write(errDetail)       

    '...you could display the error info directly in the page...
    Response.Write("Error Description: " & err.Description)
    Response.Write("Error Source: " & err.Source)
    Response.Write("Error Number: " & err.Number)

    '...or you could execute additional code when an error is thrown...
    'Insert error handling code here

    err.clear
End Sub

Can a variable number of arguments be passed to a function?

Adding to the other excellent posts.

Sometimes you don't want to specify the number of arguments and want to use keys for them (the compiler will complain if one argument passed in a dictionary is not used in the method).

def manyArgs1(args):
  print args.a, args.b #note args.c is not used here

def manyArgs2(args):
  print args.c #note args.b and .c are not used here

class Args: pass

args = Args()
args.a = 1
args.b = 2
args.c = 3

manyArgs1(args) #outputs 1 2
manyArgs2(args) #outputs 3

Then you can do things like

myfuns = [manyArgs1, manyArgs2]
for fun in myfuns:
  fun(args)

Understanding the difference between Object.create() and new SomeFunction()

This:

var foo = new Foo();

and

var foo = Object.create(Foo.prototype);

are quite similar. One important difference is that new Foo actually runs constructor code, whereas Object.create will not execute code such as

function Foo() {
    alert("This constructor does not run with Object.create");
}

Note that if you use the two-parameter version of Object.create() then you can do much more powerful things.

In Java, how can I determine if a char array contains a particular character?

The following snippets test for the "not contains" condition, as exemplified in the sample pseudocode in the question. For a direct solution with explicit looping, do this:

boolean contains = false;
for (char c : charArray) {
    if (c == 'q') {
        contains = true;
        break;
    }
}
if (!contains) {
    // do something
}

Another alternative, using the fact that String provides a contains() method:

if (!(new String(charArray).contains("q"))) {
    // do something
}

Yet another option, this time using indexOf():

if (new String(charArray).indexOf('q') == -1) {
    // do something
}

Java - Opposite of .contains (does not contain)

Maybe

if (inventory.contains("bread") && !inventory.contains("water"))

Or

if (inventory.contains("bread")) {
    if (!inventory.contains("water")) {
        // do something here
    } 
}

Show which git tag you are on?

git describe is a porcelain command, which you should avoid:

http://git-blame.blogspot.com/2013/06/checking-current-branch-programatically.html

Instead, I used:

git name-rev --tags --name-only $(git rev-parse HEAD)

Hiding the scroll bar on an HTML page

Use the CSS overflow property:

.noscroll {
  width: 150px;
  height: 150px;
  overflow: auto; /* Or hidden, or visible */
}

Here are some more examples:

How do you use https / SSL on localhost?

If you have IIS Express (with Visual Studio):

To enable the SSL within IIS Express, you have to just set “SSL Enabled = true” in the project properties window.

See the steps and pictures at this code project.

IIS Express will generate a certificate for you (you'll be prompted for it, etc.). Note that depending on configuration the site may still automatically start with the URL rather than the SSL URL. You can see the SSL URL - note the port number and replace it in your browser address bar, you should be able to get in and test.

From there you can right click on your project, click property pages, then start options and assign the start URL - put the new https with the new port (usually 44301 - notice the similarity to port 443) and your project will start correctly from then on.

enter image description here

Cannot resolve symbol AppCompatActivity - Support v7 libraries aren't recognized?

I had the same problem in my newly started project with minimum api 23, and finally i have added these lines of codes in my gradle dependency file and it solved the error:)

 implementation 'com.android.support:appcompat-v7:28.0.0'
 implementation 'com.android.support:customtabs:28.0.0'
 implementation 'com.android.support:support-vector-drawable:28.0.0'
 implementation 'com.android.support:support-media-compat:28.0.0'

Angular 2 router.navigate

If the first segment doesn't start with / it is a relative route. router.navigate needs a relativeTo parameter for relative navigation

Either you make the route absolute:

this.router.navigate(['/foo-content', 'bar-contents', 'baz-content', 'page'], this.params.queryParams)

or you pass relativeTo

this.router.navigate(['../foo-content', 'bar-contents', 'baz-content', 'page'], {queryParams: this.params.queryParams, relativeTo: this.currentActivatedRoute})

See also

Axios get in url works but with second parameter as object it doesn't

axios.get accepts a request config as the second parameter (not query string params).

You can use the params config option to set query string params as follows:

axios.get('/api', {
  params: {
    foo: 'bar'
  }
});

Edit line thickness of CSS 'underline' attribute

You can do it with a linear-gradient by setting it to be like this:

_x000D_
_x000D_
h1, a {
    display: inline;
    text-decoration: none;
    color: black;
    background-image: linear-gradient(to top, #000 12%, transparent 12%);
}
_x000D_
<h1>I'm underlined</h1>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim <a href="https://stackoverflow.com">veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in</a> reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
_x000D_
_x000D_
_x000D_

And, yes, you can change it like this...

_x000D_
_x000D_
var m = document.getElementById("m");
m.onchange = u;
function u() {
    document.getElementById("a").innerHTML = ":root { --value: " + m.value + "%;";
}
_x000D_
h1, a {
    display: inline;
    text-decoration: none;
    color: black;
    background-image: linear-gradient(to top, #000 var(--value), transparent var(--value));
}
_x000D_
<h1>I'm underlined</h1>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim <a href="https://stackoverflow.com">veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in</a> reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
<style id="a"></style>
<input type="range" min="0" max="100" id="m" />
_x000D_
_x000D_
_x000D_

Use xml.etree.ElementTree to print nicely formatted xml files

You can use the function toprettyxml() from xml.dom.minidom in order to do that:

def prettify(elem):
    """Return a pretty-printed XML string for the Element.
    """
    rough_string = ElementTree.tostring(elem, 'utf-8')
    reparsed = minidom.parseString(rough_string)
    return reparsed.toprettyxml(indent="\t")

The idea is to print your Element in a string, parse it using minidom and convert it again in XML using the toprettyxml function.

Source: http://pymotw.com/2/xml/etree/ElementTree/create.html

One line if-condition-assignment

You can definitely use num1 = (20 if someBoolValue else num1) if you want.

Java - escape string to prevent SQL injection

In case you are dealing with a legacy system, or you have too many places to switch to PreparedStatements in too little time - i.e. if there is an obstacle to using the best practice suggested by other answers, you can try AntiSQLFilter

Remove scrollbar from iframe

Adding scroll="no" and style="overflow:hidden" on iframe didn't work, I had to add style="overflow:hidden" on body of html document loaded inside iframe.

Value Change Listener to JTextField

Be aware that when the user modify the field, the DocumentListener can, sometime, receive two events. For instance if the user selects the whole field content, then press a key, you'll receive a removeUpdate (all the content is remove) and an insertUpdate. In your case, I don't think it is a problem but, generally speaking, it is. Unfortunately, it seems there's no way to track the content of the textField without subclassing JTextField. Here is the code of a class that provide a "text" property :

package net.yapbam.gui.widget;

import javax.swing.JTextField;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.PlainDocument;

/** A JTextField with a property that maps its text.
 * <br>I've found no way to track efficiently the modifications of the text of a JTextField ... so I developed this widget.
 * <br>DocumentListeners are intended to do it, unfortunately, when a text is replace in a field, the listener receive two events:<ol>
 * <li>One when the replaced text is removed.</li>
 * <li>One when the replacing text is inserted</li>
 * </ul>
 * The first event is ... simply absolutely misleading, it corresponds to a value that the text never had.
 * <br>Anoter problem with DocumentListener is that you can't modify the text into it (it throws IllegalStateException).
 * <br><br>Another way was to use KeyListeners ... but some key events are throw a long time (probably the key auto-repeat interval)
 * after the key was released. And others events (for example a click on an OK button) may occurs before the listener is informed of the change.
 * <br><br>This widget guarantees that no "ghost" property change is thrown !
 * @author Jean-Marc Astesana
 * <BR>License : GPL v3
 */

public class CoolJTextField extends JTextField {
    private static final long serialVersionUID = 1L;

    public static final String TEXT_PROPERTY = "text";

    public CoolJTextField() {
        this(0);
    }

    public CoolJTextField(int nbColumns) {
        super("", nbColumns);
        this.setDocument(new MyDocument());
    }

    @SuppressWarnings("serial")
    private class MyDocument extends PlainDocument {
        private boolean ignoreEvents = false;

        @Override
        public void replace(int offset, int length, String text, AttributeSet attrs) throws BadLocationException {
            String oldValue = CoolJTextField.this.getText();
            this.ignoreEvents = true;
            super.replace(offset, length, text, attrs);
            this.ignoreEvents = false;
            String newValue = CoolJTextField.this.getText();
            if (!oldValue.equals(newValue)) CoolJTextField.this.firePropertyChange(TEXT_PROPERTY, oldValue, newValue);
        }

        @Override
        public void remove(int offs, int len) throws BadLocationException {
            String oldValue = CoolJTextField.this.getText();
            super.remove(offs, len);
            String newValue = CoolJTextField.this.getText();
            if (!ignoreEvents && !oldValue.equals(newValue)) CoolJTextField.this.firePropertyChange(TEXT_PROPERTY, oldValue, newValue);
        }
    }

UITableview: How to Disable Selection for Some Rows but Not Others

For Swift 4.0 for example:

cell.isUserInteractionEnabled = false
cell.contentView.alpha = 0.5

How to set up a cron job to run an executable every hour?

Since I could not run the C executable that way, I wrote a simple shell script that does the following

cd /..path_to_shell_script
./c_executable_name

In the cron jobs list, I call the shell script.

What's the best way to store Phone number in Django models

I will describe what I use:

Validation: string contains more than 5 digits.

Cleaning: removing all non digits symbols, write in db only numbers. I'm lucky, because in my country (Russia) everybody has phone numbers with 10 digits. So I store in db only 10 diits. If you are writing multi-country application, then you should make a comprehensive validation.

Rendering: I write custom template tag to render it in template nicely. Or even render it like a picture - it is more safe to prevent sms spam.

AttributeError: 'datetime' module has no attribute 'strptime'

If I had to guess, you did this:

import datetime

at the top of your code. This means that you have to do this:

datetime.datetime.strptime(date, "%Y-%m-%d")

to access the strptime method. Or, you could change the import statement to this:

from datetime import datetime

and access it as you are.

The people who made the datetime module also named their class datetime:

#module  class    method
datetime.datetime.strptime(date, "%Y-%m-%d")

How to enable external request in IIS Express?

As a sidenote to this:

netsh http add urlacl url=http://vaidesg:8080/ user=everyone

This will only work on English versions of Windows. If you are using a localized version you have to replace "everyone" with something else, for example:

  • "Iedereen" when using a Dutch version
  • "Jeder" when using a German version
  • "Mindenki" when using a Hungarian version

Otherwise you will get an error (Create SDDL failed, Error: 1332)

Expected response code 220 but got code "", with message "" in Laravel

I did as per sid saying my env after updating is

MAIL_DRIVER=smtp
MAIL_HOST=smtp.gmail.com
MAIL_PORT=587
MAIL_USERNAME=<mygmailaddress>
MAIL_PASSWORD=<gmailpassword>
MAIL_ENCRYPTION=tls

this did work without 2 step verification. with 2 step verification enabled it did not work for me.

How to define constants in Visual C# like #define in C?

Check How to: Define Constants in C# on MSDN:

In C# the #define preprocessor directive cannot be used to define constants in the way that is typically used in C and C++.

How to iterate a table rows with JQuery and access some cell values?

do this:

$("tr.item").each(function(i, tr) {
    var value = $("span.value", tr).text();
    var quantity = $("input.quantity", tr).val();
});

Force encode from US-ASCII to UTF-8 (iconv)

The following converts all files in a folder.

Create backup folder of original files.

mkdir backup

Convert all files in US ASCII encoding to UTF-8 (single line command)

for f in $(file -i * .sql | grep us-ascii | cut -d ':' -f 1); do iconv -f us-ascii -t utf-8 $f -o $ f.utf-8 && mv $f backup / && mv "$f.utf-8" $f; done

Convert all files in encoding ISO 8859-1 to UTF-8 (single line command)

for f $(file -i * .sql | grep iso-8859-1 | cut -d ':' -f 1); do iconv -f iso-8859-1 -t utf-8 $f -o $f.utf-8 && mv $f backup / && mv "$f.utf-8" $f; done

Checking if a collection is empty in Java: which is the best method?

Use CollectionUtils.isEmpty(Collection coll)

Null-safe check if the specified collection is empty. Null returns true.

Parameters: coll - the collection to check, may be null

Returns: true if empty or null

Pip error: Microsoft Visual C++ 14.0 is required

I got this error when I tried to install pymssql even though Visual C++ 2015 (14.0) is installed in my system.

I resolved this error by downloading the .whl file of pymssql from here.

Once downloaded, it can be installed by the following command :

pip install python_package.whl

Hope this helps

BSTR to std::string (std::wstring) and vice versa

There is a c++ class called _bstr_t. It has useful methods and a collection of overloaded operators.

For example, you can easily assign from a const wchar_t * or a const char * just doing _bstr_t bstr = L"My string"; Then you can convert it back doing const wchar_t * s = bstr.operator const wchar_t *();. You can even convert it back to a regular char const char * c = bstr.operator char *(); You can then just use the const wchar_t * or the const char * to initialize a new std::wstring oe std::string.

Determine whether a key is present in a dictionary

In the same vein as martineau's response, the best solution is often not to check. For example, the code

if x in d:
    foo = d[x]
else:
    foo = bar

is normally written

foo = d.get(x, bar)

which is shorter and more directly speaks to what you mean.

Another common case is something like

if x not in d:
    d[x] = []

d[x].append(foo)

which can be rewritten

d.setdefault(x, []).append(foo)

or rewritten even better by using a collections.defaultdict(list) for d and writing

d[x].append(foo)

Group By Eloquent ORM

try: ->unique('column')

example:

$users = User::get()->unique('column');

How to remove duplicate objects in a List<MyObject> without equals/hashcode?

use this code

 public List<Blog> removeDuplicates(List<Blog> list) {
    // Set set1 = new LinkedHashSet(list);
    Set set = new TreeSet(new Comparator() {

        @Override
        public int compare(Object o1, Object o2) {
            if (((Blog) o1).get().equalsIgnoreCase(((Blog) o2).getId()) /*&&
                    ((Blog)o1).getName().equalsIgnoreCase(((Blog)o2).getName())*/) {
                return 0;
            }
            return 1;
        }
    });
    set.addAll(list);

    final List newList = new ArrayList(set);
    return newList;
}

MySQL, Check if a column exists in a table with SQL

This works well for me.

SHOW COLUMNS FROM `table` LIKE 'fieldname';

With PHP it would be something like...

$result = mysql_query("SHOW COLUMNS FROM `table` LIKE 'fieldname'");
$exists = (mysql_num_rows($result))?TRUE:FALSE;

Why does Lua have no "continue" statement?

I've never used Lua before, but I Googled it and came up with this:

http://www.luafaq.org/

Check question 1.26.

This is a common complaint. The Lua authors felt that continue was only one of a number of possible new control flow mechanisms (the fact that it cannot work with the scope rules of repeat/until was a secondary factor.)

In Lua 5.2, there is a goto statement which can be easily used to do the same job.

Set Windows process (or user) memory limit

Use the Application Verifier (AppVerifier) tool from Microsoft.

In my case I need to simulate memory no longer being available so I did the following in the tool:

  1. Added my application
  2. Unchecked Basic
  3. Checked Low Resource Simulation
    • Changed TimeOut to 120000 - my application will run normally for 2 minutes before anything goes into effect.
    • Changed HeapAlloc to 100 - 100% chance of heap allocation error
    • Set Stacks to true - the stack will not be able to grow any larger
  4. Save
  5. Start my application

After 2 minutes my program could no longer allocate new memory and I was able to see how everything was handled.

Behaviour of increment and decrement operators in Python

In python 3.8+ you can do :

(a:=a+1) #same as ++a (increment, then return new value)
(a:=a+1)-1 #same as a++ (return the incremented value -1) (useless)

You can do a lot of thinks with this.

>>> a = 0
>>> while (a:=a+1) < 5:
    print(a)

    
1
2
3
4

Or if you want write somthing with more sophisticated syntaxe (the goal is not optimization):

>>> del a
>>> while (a := (a if 'a' in locals() else 0) + 1) < 5:
    print(a)

    
1
2
3
4

It will return 0 even if 'a' doesn't exist without errors, and then will set it to 1

Execution failed for task ':app:compileDebugJavaWithJavac' Android Studio 3.1 Update

I'm on Android Studio 3.1 Build #AI-173.4670197, built on March 22, 2018 JRE: 1.8.0_152-release-1024-b02 amd64 JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o Windows 10 10.

I had the same issue and it only worked after changing my build.grade file to

    compileOptions {                                                          
    sourceCompatibility JavaVersion.VERSION_1_8 
    targetCompatibility JavaVersion.VERSION_1_8


}

Prior to this change nothing worked and all compiles would fail. previously my settings were

sourceCompatibility JavaVersion.VERSION_1_7 
targetCompatibility JavaVersion.VERSION_1_8