Programs & Examples On #Asp.net customcontrol

Adding text to a cell in Excel using VBA

You need to use Range and Value functions.
Range would be the cell where you want the text you want
Value would be the text that you want in that Cell

Range("A1").Value="whatever text"

Load and execution sequence of a web page?

AFAIK, the browser (at least Firefox) requests every resource as soon as it parses it. If it encounters an img tag it will request that image as soon as the img tag has been parsed. And that can be even before it has received the totality of the HTML document... that is it could still be downloading the HTML document when that happens.

For Firefox, there are browser queues that apply, depending on how they are set in about:config. For example it will not attempt to download more then 8 files at once from the same server... the additional requests will be queued. I think there are per-domain limits, per proxy limits, and other stuff, which are documented on the Mozilla website and can be set in about:config. I read somewhere that IE has no such limits.

The jQuery ready event is fired as soon as the main HTML document has been downloaded and it's DOM parsed. Then the load event is fired once all linked resources (CSS, images, etc.) have been downloaded and parsed as well. It is made clear in the jQuery documentation.

If you want to control the order in which all that is loaded, I believe the most reliable way to do it is through JavaScript.

Truncating all tables in a Postgres database

You can do this with bash also:

#!/bin/bash
PGPASSWORD='' psql -h 127.0.0.1 -Upostgres sng --tuples-only --command "SELECT 'TRUNCATE TABLE ' || schemaname || '.' ||  tablename || ';' FROM pg_tables WHERE schemaname in ('cms_test', 'ids_test', 'logs_test', 'sps_test');" | 
tr "\\n" " " | 
xargs -I{} psql -h 127.0.0.1 -Upostgres sng --command "{}"

You will need to adjust schema names, passwords and usernames to match your schemas.

Create an empty data.frame

You can do it without specifying column types

df = data.frame(matrix(vector(), 0, 3,
                dimnames=list(c(), c("Date", "File", "User"))),
                stringsAsFactors=F)

How to show a confirm message before delete?

I'm useing this way (in laravel)-

<form id="delete-{{$category->id}}" action="{{route('category.destroy',$category->id)}}" style="display: none;" method="POST">
 @csrf
 @method('DELETE')
</form>

<a href="#" onclick="if (confirm('Are you sure want to delete this item?')) {
           event.preventDefault();
           document.getElementById('delete-{{$category->id}}').submit();
         }else{
           event.preventDefault();
         }">
  <i class="fa fa-trash"></i>
</a>

Join two sql queries

If you assume that values exist for all activities in both years then just do an inner join as follows

 select act.activity, t1.amount as "Total 2009", t2.amount as "Total 2008"
from Activities as act,
    (select activityid,  SUM(Amount) as amount
    from Activities, Incomes
    where Activities.UnitName = ? AND
          Incomes.ActivityId = Activities.ActivityID
    GROUP BY Activityid) as t1,
    (select activityid, SUM(Amount) as amount
    from Activities, Incomes2008
    where Activities.UnitName = ? AND
          Incomes2008.ActivityId = Activities.ActivityID
    GROUP BY Activityid) as t2
    WHERE t1.activityid= t2.activityid
    AND act.activityId = t1.activityId
    ORDER BY act.activity

If you can't assume this, then look at doing an outer join

Disabling vertical scrolling in UIScrollView

Just set the y to be always on top. Need to conform with UIScrollViewDelegate

func scrollViewDidScroll(scrollView: UIScrollView) {
        scrollView.contentOffset.y = 0.0
}

This will keep the Deceleration / Acceleration effect of the scrolling.

Tablix: Repeat header rows on each page not working - Report Builder 3.0

Open Advanced Mode in the Groupings pane. (Click the arrow to the right of the Column Groups and select Advanced Mode.)

In the Row Groups area (not Column Groups), click on a Static group, which highlights the corresponding textbox in the tablix.

Click through each Static group until it highlights the leftmost column header. This is generally the first Static group listed.

In the properties grid:

  • set KeepWithGroup to After
  • set RepeatOnNewPage to True for repeating headers
  • set FixedData to True for keeping headers visible

How to uninstall an older PHP version from centOS7

Subscribing to the IUS Community Project Repository

cd ~
curl 'https://setup.ius.io/' -o setup-ius.sh

Run the script:

sudo bash setup-ius.sh

Upgrading mod_php with Apache

This section describes the upgrade process for a system using Apache as the web server and mod_php to execute PHP code. If, instead, you are running Nginx and PHP-FPM, skip ahead to the next section.

Begin by removing existing PHP packages. Press y and hit Enter to continue when prompted.

sudo yum remove php-cli mod_php php-common

Install the new PHP 7 packages from IUS. Again, press y and Enter when prompted.

sudo yum install mod_php70u php70u-cli php70u-mysqlnd

Finally, restart Apache to load the new version of mod_php:

sudo apachectl restart

You can check on the status of Apache, which is managed by the httpd systemd unit, using systemctl:

systemctl status httpd

make arrayList.toArray() return more specific types

 public static <E> E[] arrayListToTypedArray(List<E> list) {

    if (list == null) {
      return null;
    }
    int noItems = list.size();
    if (noItems == 0) {
      return null;
    }

    E[] listAsTypedArray;
    E typeHelper = list.get(0);

    try {
      Object o = Array.newInstance(typeHelper.getClass(), noItems);
      listAsTypedArray = (E[]) o;
      for (int i = 0; i < noItems; i++) {
        Array.set(listAsTypedArray, i, list.get(i));
      }
    } catch (Exception e) {
      return null;
    }

    return listAsTypedArray;
  }

LINQ - Full Outer Join

Thank You everybody for the interesting posts!

I modified the code because in my case I needed

  • a personalized join predicate
  • a personalized union distinct comparer

For the ones interested this is my modified code (in VB, sorry)

    Module MyExtensions
        <Extension()>
        Friend Function FullOuterJoin(Of TA, TB, TResult)(ByVal a As IEnumerable(Of TA), ByVal b As IEnumerable(Of TB), ByVal joinPredicate As Func(Of TA, TB, Boolean), ByVal projection As Func(Of TA, TB, TResult), ByVal comparer As IEqualityComparer(Of TResult)) As IEnumerable(Of TResult)
            Dim joinL =
                From xa In a
                From xb In b.Where(Function(x) joinPredicate(xa, x)).DefaultIfEmpty()
                Select projection(xa, xb)
            Dim joinR =
                From xb In b
                From xa In a.Where(Function(x) joinPredicate(x, xb)).DefaultIfEmpty()
                Select projection(xa, xb)
            Return joinL.Union(joinR, comparer)
        End Function
    End Module

    Dim fullOuterJoin = lefts.FullOuterJoin(
        rights,
        Function(left, right) left.Code = right.Code And (left.Amount [...] Or left.Description.Contains [...]),
        Function(left, right) New CompareResult(left, right),
        New MyEqualityComparer
    )

    Public Class MyEqualityComparer
        Implements IEqualityComparer(Of CompareResult)

        Private Function GetMsg(obj As CompareResult) As String
            Dim msg As String = ""
            msg &= obj.Code & "_"
            [...]
            Return msg
        End Function

        Public Overloads Function Equals(x As CompareResult, y As CompareResult) As Boolean Implements IEqualityComparer(Of CompareResult).Equals
            Return Me.GetMsg(x) = Me.GetMsg(y)
        End Function

        Public Overloads Function GetHashCode(obj As CompareResult) As Integer Implements IEqualityComparer(Of CompareResult).GetHashCode
            Return Me.GetMsg(obj).GetHashCode
        End Function
    End Class

How can I get the name of an html page in Javascript?

Single statement that works with trailing slash. If you are using IE11 you'll have to polyfill the filter function.

var name = window.location.pathname
        .split("/")
        .filter(function (c) { return c.length;})
        .pop();

How to validate a form with multiple checkboxes to have atleast one checked

How about this:

$(document).ready(function() {
    $('#subscribeForm').submit(function() {
        var $fields = $(this).find('input[name="list"]:checked');
        if (!$fields.length) {
            alert('You must check at least one box!');
            return false; // The form will *not* submit
        }
    });
});

Variables within app.config/web.config

A slightly more complicated, but far more flexible, alternative is to create a class that represents a configuration section. In your app.config / web.config file, you can have this:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <!-- This section must be the first section within the <configuration> node -->
    <configSections>
        <section name="DirectoryInfo" type="MyProjectNamespace.DirectoryInfoConfigSection, MyProjectAssemblyName" />
    </configSections>

    <DirectoryInfo>
        <Directory MyBaseDir="C:\MyBase" Dir1="Dir1" Dir2="Dir2" />
    </DirectoryInfo>
</configuration>

Then, in your .NET code (I'll use C# in my example), you can create two classes like this:

using System;
using System.Configuration;

namespace MyProjectNamespace {

    public class DirectoryInfoConfigSection : ConfigurationSection {

        [ConfigurationProperty("Directory")]
        public DirectoryConfigElement Directory {
            get {
                return (DirectoryConfigElement)base["Directory"];
            }
    }

    public class DirectoryConfigElement : ConfigurationElement {

        [ConfigurationProperty("MyBaseDir")]
        public String BaseDirectory {
            get {
                return (String)base["MyBaseDir"];
            }
        }

        [ConfigurationProperty("Dir1")]
        public String Directory1 {
            get {
                return (String)base["Dir1"];
            }
        }

        [ConfigurationProperty("Dir2")]
        public String Directory2 {
            get {
                return (String)base["Dir2"];
            }
        }
        // You can make custom properties to combine your directory names.
        public String Directory1Resolved {
            get {
                return System.IO.Path.Combine(BaseDirectory, Directory1);
            }
        }
    }
}

Finally, in your program code, you can access your app.config variables, using your new classes, in this manner:

DirectoryInfoConfigSection config =
  (DirectoryInfoConfigSection)ConfigurationManager.GetSection("DirectoryInfo");
String dir1Path = config.Directory.Directory1Resolved;  // This value will equal "C:\MyBase\Dir1"

node.js execute system command synchronously

I had a similar problem and I ended up writing a node extension for this. You can check out the git repository. It's open source and free and all that good stuff !

https://github.com/aponxi/npm-execxi

ExecXI is a node extension written in C++ to execute shell commands one by one, outputting the command's output to the console in real-time. Optional chained, and unchained ways are present; meaning that you can choose to stop the script after a command fails (chained), or you can continue as if nothing has happened !

Usage instructions are in the ReadMe file. Feel free to make pull requests or submit issues!

EDIT: However it doesn't return the stdout yet... Just outputs them in real-time. It does now. Well, I just released it today. Maybe we can build on it.

Anyway, I thought it was worth to mention it.

How to build splash screen in windows forms application?

Here is the easiest way of creating a splash screen:

First of all, add the following line of code before the namespace in Form1.cs code:

using System.Threading;

Now, follow the following steps:

  1. Add a new form in you application

  2. Name this new form as FormSplashScreen

  3. In the BackgroundImage property, choose an image from one of your folders

  4. Add a progressBar

  5. In the Dock property, set it as Bottom

  6. In MarksAnimationSpeed property, set as 50

  7. In your main form, named as Form1.cs by default, create the following method:

     private void StartSplashScreen()
     {
         Application.Run(new Forms.FormSplashScreen());
     }
    
  8. In the constructor method of Form1.cs, add the following code:

     public Form1()
     {
         Thread t = new Thread(new ThreadStart(StartSplashScreen));
         t.Start();
         Thread.Sleep(5000);
    
         InitializeComponent();//This code is automatically generated by Visual Studio
    
         t.Abort();
     }
    
  9. Now, just run the application, it is going to work perfectly.

How do you set a default value for a MySQL Datetime column?

this is indeed terrible news.here is a long pending bug/feature request for this. that discussion also talks about the limitations of timestamp data type.

I am seriously wondering what is the issue with getting this thing implemented.

Why am I getting the error "connection refused" in Python? (Sockets)

This error means that for whatever reason the client cannot connect to the port on the computer running server script. This can be caused by few things, like lack of routing to the destination, but since you can ping the server, it should not be the case. The other reason might be that you have a firewall somewhere between your client and the server - it could be on server itself or on the client. Given your network addressing, I assume both server and client are on the same LAN, so there shouldn't be any router/firewall involved that could block the traffic. In this case, I'd try the following:

  • check if you really have that port listening on the server (this should tell you if your code does what you think it should): based on your OS, but on linux you could do something like netstat -ntulp
  • check from the server, if you're accepting the connections to the server: again based on your OS, but telnet LISTENING_IP LISTENING_PORT should do the job
  • check if you can access the port of the server from the client, but not using the code: just us the telnet (or appropriate command for your OS) from the client

and then let us know the findings.

CSS3 selector to find the 2nd div of the same class

And for people who are looking for a jQuery compatible answer:

$('.foo:eq(1)').css('color', 'red');

HTML:

<div>
  <div class="other"></div>
  <div class="foo"></div>
  <div class="foo">Find me</div>
  ...    

What causes a Python segmentation fault?

This happens when a python extension (written in C) tries to access a memory beyond reach.

You can trace it in following ways.

  • Add sys.settrace at the very first line of the code.
  • Use gdb as described by Mark in this answer.. At the command prompt

    gdb python
    (gdb) run /path/to/script.py
    ## wait for segfault ##
    (gdb) backtrace
    ## stack trace of the c code
    

How to conditionally take action if FINDSTR fails to find a string

In DOS/Windows Batch most commands return an exitCode, called "errorlevel", that is a value that customarily is equal to zero if the command ends correctly, or a number greater than zero if ends because an error, with greater numbers for greater errors (hence the name).

There are a couple methods to check that value, but the original one is:

IF ERRORLEVEL value command

Previous IF test if the errorlevel returned by the previous command was GREATER THAN OR EQUAL the given value and, if this is true, execute the command. For example:

verify bad-param
if errorlevel 1 echo Errorlevel is greater than or equal 1
echo The value of errorlevel is: %ERRORLEVEL%

Findstr command return 0 if the string was found and 1 if not:

CD C:\MyFolder
findstr /c:"stringToCheck" fileToCheck.bat
IF ERRORLEVEL 1 XCOPY "C:\OtherFolder\fileToCheck.bat" "C:\MyFolder" /s /y

Previous code will copy the file if the string was NOT found in the file.

CD C:\MyFolder
findstr /c:"stringToCheck" fileToCheck.bat
IF NOT ERRORLEVEL 1 XCOPY "C:\OtherFolder\fileToCheck.bat" "C:\MyFolder" /s /y

Previous code copy the file if the string was found. Try this:

findstr "string" file
if errorlevel 1 (
    echo String NOT found...
) else (
    echo String found
)

Excel - extracting data based on another list

New Excel versions

=IF(ISNA(VLOOKUP(A1,B,B,1,FALSE)),"",A1)

Older Excel versions

=IF(ISNA(VLOOKUP(A1;B:B;1;FALSE));"";A1)

That is: "If the value of A1 exists in the B column, display it here. If it doesn't exist, leave it empty."

How to run Spring Boot web application in Eclipse itself?

This answer is late, but I was having the same issue. I found something that works.
In eclipse Project Explorer, right click the project name -> select "Run As" -> "Maven Build..."
In the goals, enter spring-boot:run then click Run button.

I have the STS plug-in (i.e. SpringSource Tool Suite), so on some projects I will get a "Spring Boot App" option under Run As. But, it doesn't always show up for some reason. I use the above workaround for those.
Here is a reference that explains how to run Spring boot apps:
Spring boot tutorial

Just what is an IntPtr exactly?

A direct interpretation

An IntPtr is an integer which is the same size as a pointer.

You can use IntPtr to store a pointer value in a non-pointer type. This feature is important in .NET since using pointers is highly error prone and therefore illegal in most contexts. By allowing the pointer value to be stored in a "safe" data type, plumbing between unsafe code segments may be implemented in safer high-level code -- or even in a .NET language that doesn't directly support pointers.

The size of IntPtr is platform-specific, but this detail rarely needs to be considered, since the system will automatically use the correct size.

The name "IntPtr" is confusing -- something like Handle might have been more appropriate. My initial guess was that "IntPtr" was a pointer to an integer. The MSDN documentation of IntPtr goes into somewhat cryptic detail without ever providing much insight about the meaning of the name.

An alternative perspective

An IntPtr is a pointer with two limitations:

  1. It cannot be directly dereferenced
  2. It doesn't know the type of the data that it points to.

In other words, an IntPtr is just like a void* -- but with the extra feature that it can (but shouldn't) be used for basic pointer arithmetic.

In order to dereference an IntPtr, you can either cast it to a true pointer (an operation which can only be performed in "unsafe" contexts) or you can pass it to a helper routine such as those provided by the InteropServices.Marshal class. Using the Marshal class gives the illusion of safety since it doesn't require you to be in an explicit "unsafe" context. However, it doesn't remove the risk of crashing which is inherent in using pointers.

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

For my case none of the suggested solutions worked so I tried to fix it myself and I got it resolved.

For me I am getting this error on my AWS EC2 UBUNTU instance, what I did to resolve it was to edit the ssh config (or add it if it does not exist).

sudo nano ~/.ssh/config

And I added the following

Host github.com
 Hostname ssh.github.com
 Port 443

Then, run the command ssh -T [email protected] to confirm if the issue is fixed.

According to this

Sometimes, firewalls refuse to allow SSH connections entirely. If using HTTPS cloning with credential caching is not an option, you can attempt to clone using an SSH connection made over the HTTPS port. Most firewall rules should allow this, but proxy servers may interfere

Hopefully this helps anyone else who's having the same issue I did.

How do I declare an array of undefined or no initial size?

Modern C, aka C99, has variable length arrays, VLA. Unfortunately, not all compilers support this but if yours does this would be an alternative.

Get environment variable value in Dockerfile

Load environment variables from a file you create at runtime.

export MYVAR="my_var_outside"
cat > build/env.sh <<EOF
MYVAR=${MYVAR}
EOF

... then in the Dockerfile

ADD build /build
RUN /build/test.sh

where test.sh loads MYVAR from env.sh

#!/bin/bash
. /build/env.sh
echo $MYVAR > /tmp/testfile

Is there a C# case insensitive equals operator?

Operator? NO, but I think you can change your culture so that string comparison is not case-sensitive.

// you'll want to change this...
System.Threading.Thread.CurrentThread.CurrentCulture
// and you'll want to custimize this
System.Globalization.CultureInfo.CompareInfo

I'm confident that it will change the way that strings are being compared by the equals operator.

How to simulate a mouse click using JavaScript?

Here's a pure JavaScript function which will simulate a click (or any mouse event) on a target element:

function simulatedClick(target, options) {

  var event = target.ownerDocument.createEvent('MouseEvents'),
      options = options || {},
      opts = { // These are the default values, set up for un-modified left clicks
        type: 'click',
        canBubble: true,
        cancelable: true,
        view: target.ownerDocument.defaultView,
        detail: 1,
        screenX: 0, //The coordinates within the entire page
        screenY: 0,
        clientX: 0, //The coordinates within the viewport
        clientY: 0,
        ctrlKey: false,
        altKey: false,
        shiftKey: false,
        metaKey: false, //I *think* 'meta' is 'Cmd/Apple' on Mac, and 'Windows key' on Win. Not sure, though!
        button: 0, //0 = left, 1 = middle, 2 = right
        relatedTarget: null,
      };

  //Merge the options with the defaults
  for (var key in options) {
    if (options.hasOwnProperty(key)) {
      opts[key] = options[key];
    }
  }

  //Pass in the options
  event.initMouseEvent(
      opts.type,
      opts.canBubble,
      opts.cancelable,
      opts.view,
      opts.detail,
      opts.screenX,
      opts.screenY,
      opts.clientX,
      opts.clientY,
      opts.ctrlKey,
      opts.altKey,
      opts.shiftKey,
      opts.metaKey,
      opts.button,
      opts.relatedTarget
  );

  //Fire the event
  target.dispatchEvent(event);
}

Here's a working example: http://www.spookandpuff.com/examples/clickSimulation.html

You can simulate a click on any element in the DOM. Something like simulatedClick(document.getElementById('yourButtonId')) would work.

You can pass in an object into options to override the defaults (to simulate which mouse button you want, whether Shift/Alt/Ctrl are held, etc. The options it accepts are based on the MouseEvents API.

I've tested in Firefox, Safari and Chrome. Internet Explorer might need special treatment, I'm not sure.

How to reverse apply a stash?

This is long over due, but if i interpret the problem correctly i have found a simple solution, note, this is an explanation in my own terminology:

git stash [save] will save away current changes and set your current branch to the "clean state"

git stash list gives something like: stash@{0}: On develop: saved testing-stuff

git apply stash@{0} will set current branch as before stash [save]

git checkout . Will set current branch as after stash [save]

The code that is saved in the stash is not lost, it can be found by git apply stash@{0} again.

Anywhay, this worked for me!

Insert php variable in a href

You could try:

<a href="<?php echo $directory ?>">The link to the file</a>

Or for PHP 5.4+ (<?= is the PHP short echo tag):

<a href="<?= $directory ?>">The link to the file</a>

But your path is relative to the server, don't forget that.

Get current clipboard content?

You can use

window.clipboardData.getData('Text')

to get the content of user's clipboard in IE. However, in other browser you may need to use flash to get the content, since there is no standard interface to access the clipboard. May be you can have try this plugin Zero Clipboard

git ignore all files of a certain type, except those in a specific subfolder

An optional prefix ! which negates the pattern; any matching file excluded by a previous pattern will become included again. If a negated pattern matches, this will override lower precedence patterns sources.

http://schacon.github.com/git/gitignore.html

*.json
!spec/*.json

Checking the form field values before submitting that page

use return before calling the function, while you click the submit button, two events(form posting as you used submit button and function call for onclick) will happen, to prevent form posting you have to return false, you have did it, also you have to specify the return i.e, to expect a value from the function,

this is a code:

input type="submit" name="continue" value="submit" onClick="**return** checkform();"

Optional Parameters in Go?

Neither optional parameters nor function overloading are supported in Go. Go does support a variable number of parameters: Passing arguments to ... parameters

Comparing mongoose _id and strings

According to the above,i found three ways to solve the problem.

  1. AnotherMongoDocument._id.toString()
  2. JSON.stringify(AnotherMongoDocument._id)
  3. results.userId.equals(AnotherMongoDocument._id)

How can I format a String number to have commas and round?

Once you've converted your String to a number, you can use

// format the number for the default locale
NumberFormat.getInstance().format(num)

or

// format the number for a particular locale
NumberFormat.getInstance(locale).format(num)

How to use Macro argument as string literal?

Use the preprocessor # operator:

#define CALL_DO_SOMETHING(VAR) do_something(#VAR, VAR);

How to allow remote access to my WAMP server for Mobile(Android)

I assume you are using windows. Open the command prompt and type ipconfig and find out your local address (on your pc) it should look something like 192.168.1.13 or 192.168.0.5 where the end digit is the one that changes. It should be next to IPv4 Address.

If your WAMP does not use virtual hosts the next step is to enter that IP address on your phones browser ie http://192.168.1.13 If you have a virtual host then you will need root to edit the hosts file.

If you want to test the responsiveness / mobile design of your website you can change your user agent in chrome or other browsers to mimic a mobile.

See http://googlesystem.blogspot.co.uk/2011/12/changing-user-agent-new-google-chrome.html.

Edit: Chrome dev tools now has a mobile debug tool where you can change the size of the viewport, spoof user agents, connections (4G, 3G etc).

If you get forbidden access then see this question WAMP error: Forbidden You don't have permission to access /phpmyadmin/ on this server. Basically, change the occurrances of deny,allow to allow,deny in the httpd.conf file. You can access this by the WAMP menu.

To eliminate possible causes of the issue for now set your config file to

<Directory />
    Options FollowSymLinks
    AllowOverride All
    Order allow,deny
    Allow from all
    <RequireAll>
        Require all granted
    </RequireAll>
</Directory>

As thatis working for my windows PC, if you have the directory config block as well change that also to allow all.

Config file that fixed the problem:

https://gist.github.com/samvaughton/6790739

Problem was that the /www apache directory config block still had deny set as default and only allowed from localhost.

Manipulating an Access database from Java without ODBC

UCanAccess is a pure Java JDBC driver that allows us to read from and write to Access databases without using ODBC. It uses two other packages, Jackcess and HSQLDB, to perform these tasks. The following is a brief overview of how to get it set up.

 

Option 1: Using Maven

If your project uses Maven you can simply include UCanAccess via the following coordinates:

groupId: net.sf.ucanaccess
artifactId: ucanaccess

The following is an excerpt from pom.xml, you may need to update the <version> to get the most recent release:

  <dependencies>
    <dependency>
        <groupId>net.sf.ucanaccess</groupId>
        <artifactId>ucanaccess</artifactId>
        <version>4.0.4</version>
    </dependency>
  </dependencies>

 

Option 2: Manually adding the JARs to your project

As mentioned above, UCanAccess requires Jackcess and HSQLDB. Jackcess in turn has its own dependencies. So to use UCanAccess you will need to include the following components:

UCanAccess (ucanaccess-x.x.x.jar)
HSQLDB (hsqldb.jar, version 2.2.5 or newer)
Jackcess (jackcess-2.x.x.jar)
commons-lang (commons-lang-2.6.jar, or newer 2.x version)
commons-logging (commons-logging-1.1.1.jar, or newer 1.x version)

Fortunately, UCanAccess includes all of the required JAR files in its distribution file. When you unzip it you will see something like

ucanaccess-4.0.1.jar  
  /lib/
    commons-lang-2.6.jar  
    commons-logging-1.1.1.jar  
    hsqldb.jar  
    jackcess-2.1.6.jar

All you need to do is add all five (5) JARs to your project.

NOTE: Do not add loader/ucanload.jar to your build path if you are adding the other five (5) JAR files. The UcanloadDriver class is only used in special circumstances and requires a different setup. See the related answer here for details.

Eclipse: Right-click the project in Package Explorer and choose Build Path > Configure Build Path.... Click the "Add External JARs..." button to add each of the five (5) JARs. When you are finished your Java Build Path should look something like this

BuildPath.png

NetBeans: Expand the tree view for your project, right-click the "Libraries" folder and choose "Add JAR/Folder...", then browse to the JAR file.

nbAddJar.png

After adding all five (5) JAR files the "Libraries" folder should look something like this:

nbLibraries.png

IntelliJ IDEA: Choose File > Project Structure... from the main menu. In the "Libraries" pane click the "Add" (+) button and add the five (5) JAR files. Once that is done the project should look something like this:

IntelliJ.png

 

That's it!

Now "U Can Access" data in .accdb and .mdb files using code like this

// assumes...
//     import java.sql.*;
Connection conn=DriverManager.getConnection(
        "jdbc:ucanaccess://C:/__tmp/test/zzz.accdb");
Statement s = conn.createStatement();
ResultSet rs = s.executeQuery("SELECT [LastName] FROM [Clients]");
while (rs.next()) {
    System.out.println(rs.getString(1));
}

 

Disclosure

At the time of writing this Q&A I had no involvement in or affiliation with the UCanAccess project; I just used it. I have since become a contributor to the project.

Display names of all constraints for a table in Oracle SQL

Often enterprise databases have several users and I'm not aways on the right one :

SELECT * FROM ALL_CONSTRAINTS WHERE table_name = 'YOUR TABLE NAME' ;

Picked from Oracle documentation

Removing NA observations with dplyr::filter()

From @Ben Bolker:

[T]his has nothing specifically to do with dplyr::filter()

From @Marat Talipov:

[A]ny comparison with NA, including NA==NA, will return NA

From a related answer by @farnsy:

The == operator does not treat NA's as you would expect it to.

Think of NA as meaning "I don't know what's there". The correct answer to 3 > NA is obviously NA because we don't know if the missing value is larger than 3 or not. Well, it's the same for NA == NA. They are both missing values but the true values could be quite different, so the correct answer is "I don't know."

R doesn't know what you are doing in your analysis, so instead of potentially introducing bugs that would later end up being published an embarrassing you, it doesn't allow comparison operators to think NA is a value.

SVG drop shadow using css3

Black text with white shadow

Another way, I used for white shadow (on text): create a clone for shadow:

Note: This require xmlns:xlink="http://www.w3.org/1999/xlink" at SVG declaration.

Real text value is located in <defs> section, with position and style, but without a fill definition.

The text is cloned two times: first for shadow and second for the text itself.

_x000D_
_x000D_
<svg xmlns="http://www.w3.org/2000/svg" width="640" height="70"_x000D_
    xmlns:xlink="http://www.w3.org/1999/xlink">_x000D_
  <defs>_x000D_
  <filter id="Blur"><feGaussianBlur stdDeviation="0.8" /></filter>_x000D_
  <text style="font-family:sans,helvetica;font-weight:bold;font-size:12pt"_x000D_
      id="Text"><tspan x="12" y="19">_x000D_
        Black text with white shadow_x000D_
    </tspan></text>_x000D_
  </defs>_x000D_
  <rect style="fill:#8AB" width="640" height="70" />_x000D_
  <use style="fill:white;" filter="url(#Blur)" xlink:href="#Text"_x000D_
      transform="translate(1.8,.9)"/>_x000D_
  <use style="fill:black;" xlink:href="#Text"/>_x000D_
</svg>
_x000D_
_x000D_
_x000D_

More distant shadow with biggest value as blur deviation:

_x000D_
_x000D_
<svg xmlns="http://www.w3.org/2000/svg" width="640" height="70"_x000D_
    xmlns:xlink="http://www.w3.org/1999/xlink">_x000D_
  <defs>_x000D_
  <filter id="Blur"><feGaussianBlur stdDeviation="3" /></filter>_x000D_
  <text style="font-family:sans,helvetica;font-weight:bold;font-size:12pt"_x000D_
      id="Text"><tspan x="12" y="19">_x000D_
        Black text with white shadow_x000D_
    </tspan></text>_x000D_
  </defs>_x000D_
  <rect style="fill:#8AB" width="640" height="70" />_x000D_
  <use style="fill:white;" filter="url(#Blur)" xlink:href="#Text"_x000D_
      transform="translate(7,5)"/>_x000D_
  <use style="fill:black;" xlink:href="#Text"/>_x000D_
</svg>
_x000D_
_x000D_
_x000D_

You can use this same approach with regular SVG objects.

With same requirement: No fill definition at <defs> section!

_x000D_
_x000D_
<svg xmlns="http://www.w3.org/2000/svg" width="364" height="172"_x000D_
    xmlns:xlink="http://www.w3.org/1999/xlink">_x000D_
  <defs>_x000D_
    <filter id="Blur"><feGaussianBlur stdDeviation="0.8" /></filter>_x000D_
    <g transform="matrix(.7,0,0,.7,-117.450795,-335.320895)" id="Img">_x000D_
        <g transform="matrix(12.997776,0,0,-12.997776,389.30313,662.04015)">_x000D_
            <path d="m 0,0 -1.107,0 c -0.039,0 -0.067,0.044 -0.067,0.086 0,0.015 0.589,1.914 0.589,1.914 0.021,0.071 0.023,0.073 0.031,0.073 l 0.001,0 c 0.009,0 0.01,-0.002 0.031,-0.073 0,0 0.589,-1.899 0.589,-1.914 C 0.067,0.044 0.037,0 0,0 M 1.493,4.345 C 1.482,4.383 1.448,4.411 1.408,4.414 l -4.065,0 C -2.698,4.41 -2.731,4.383 -2.742,4.346 c 0,0 -2.247,-7.418 -2.247,-7.432 0,-0.037 0.029,-0.067 0.067,-0.067 l 2.687,0 c 0.021,0.008 0.037,0.028 0.042,0.051 l 0.313,1 c 0.01,0.025 0.033,0.042 0.061,0.043 l 2.479,0.002 c 0.027,-0.002 0.051,-0.021 0.061,-0.045 l 0.32,-1 c 0.005,-0.023 0.021,-0.044 0.042,-0.052 0,0 2.642,10e-4 2.644,10e-4 0.037,0 0.068,0.028 0.068,0.065 0,0.013 -2.302,7.433 -2.302,7.433" />_x000D_
        </g>_x000D_
        <g transform="matrix(12.997776,0,0,-12.997776,508.27177,644.93113)">_x000D_
            <path d="m 0,0 -1.651,-0.001 c 0,0 -0.044,0.013 -0.044,0.063 l -10e-4,0.833 c 0,0.05 0.044,0.063 0.044,0.063 l 1.514,0 C 0.038,0.958 0.394,0.87 0.394,0.463 0.394,0.056 0,0 0,0 m 7.916,0.645 3.741,0 0,2.453 -4.81,0 C 6.397,3.098 5.764,2.866 5.401,2.597 5.038,2.328 4.513,1.715 4.513,0.87 c 0,-0.845 0.513,-1.502 0.513,-1.502 0.263,-0.326 0.925,-1.005 0.925,-1.005 0.015,-0.016 0.024,-0.037 0.024,-0.061 0,-0.051 -0.041,-0.092 -0.092,-0.092 l -3.705,0 c -0.451,0.002 -0.482,0.181 -0.482,0.207 0,0.046 0.056,0.075 0.056,0.075 0.169,0.081 0.514,0.35 0.514,0.35 0.732,0.57 0.82,1.352 0.82,1.771 0,0.42 -0.063,1.163 -0.814,1.814 C 1.521,3.078 0.57,3.096 0.57,3.096 l -5.287,0 c 0,0 0,-7.52 0,-7.522 0,-0.024 0.022,-0.043 0.046,-0.043 l 2.943,0 0,2.11 c 0,0.037 0.057,0 0.057,0 l 1.533,-1.54 c 0.545,-0.551 1.446,-0.57 1.446,-0.57 l 5.796,0.001 c 0.989,0 1.539,0.538 1.69,0.688 0.15,0.151 0.651,0.714 0.651,1.647 0,0.932 -0.426,1.409 -0.608,1.628 C 8.675,-0.309 8.029,0.375 7.894,0.517 7.878,0.53 7.868,0.55 7.868,0.572 c 0,0.033 0.019,0.064 0.048,0.073" />_x000D_
        </g>_x000D_
        <g transform="matrix(12.997776,0,0,-12.997776,306.99861,703.01559)">_x000D_
            <path d="m 0,0 c 0.02,0 0.034,0.014 0.04,0.036 0,0 2.277,7.479 2.277,7.486 0,0.02 -0.012,0.042 -0.031,0.044 0,0 -2.805,0 -2.807,0 -0.014,0 -0.023,-0.011 -0.026,-0.026 0,-0.001 -0.581,-1.945 -0.581,-1.946 -0.004,-0.016 -0.012,-0.026 -0.026,-0.026 -0.014,0 -0.026,0.014 -0.028,0.026 L -1.79,7.541 c -0.002,0.013 -0.012,0.025 -0.026,0.025 -10e-4,0 -3.1,0.001 -3.1,0.001 -0.009,-0.002 -0.017,-0.01 -0.02,-0.018 0,0 -0.545,-1.954 -0.545,-1.954 -0.003,-0.017 -0.012,-0.027 -0.027,-0.027 -0.013,0 -0.024,0.01 -0.026,0.023 l -0.578,1.952 c -0.001,0.012 -0.011,0.022 -0.023,0.024 l -2.992,0 c -0.024,0 -0.044,-0.02 -0.044,-0.045 0,-0.004 10e-4,-0.012 10e-4,-0.012 0,0 2.31,-7.471 2.311,-7.474 C -6.853,0.014 -6.839,0 -6.819,0 c 0.003,0 2.485,-0.001 2.485,-0.001 0.015,0.002 0.03,0.019 0.034,0.037 10e-4,0 0.865,2.781 0.865,2.781 0.005,0.017 0.012,0.027 0.026,0.027 0.015,0 0.023,-0.012 0.027,-0.026 L -2.539,0.024 C -2.534,0.01 -2.521,0 -2.505,0 -2.503,0 0,0 0,0" />_x000D_
        </g>_x000D_
        <g transform="matrix(12.997776,0,0,-12.997776,278.90126,499.03369)">_x000D_
            <path d="m 0,0 c -0.451,0 -1.083,-0.232 -1.446,-0.501 -0.363,-0.269 -0.888,-0.882 -0.888,-1.727 0,-0.845 0.513,-1.502 0.513,-1.502 0.263,-0.326 0.925,-1.01 0.925,-1.01 0.015,-0.016 0.024,-0.037 0.024,-0.06 0,-0.051 -0.041,-0.093 -0.092,-0.093 -0.008,0 -6.046,0 -6.046,0 l 0,-2.674 7.267,0 c 0.988,0 1.539,0.538 1.69,0.689 0.15,0.15 0.65,0.713 0.65,1.646 0,0.932 -0.425,1.414 -0.607,1.633 -0.162,0.196 -0.808,0.876 -0.943,1.017 -0.016,0.014 -0.026,0.034 -0.026,0.056 0,0.033 0.019,0.063 0.048,0.073 l 3.5,0 0,-5.114 2.691,0 0,5.101 3.267,0 0,2.466 L 0,0 Z" />_x000D_
        </g>_x000D_
        <g transform="matrix(12.997776,0,0,-12.997776,583.96822,539.30215)">_x000D_
            <path d="m 0,0 -1.651,-0.001 c 0,0 -0.044,0.013 -0.044,0.063 l -10e-4,0.833 c 0,0.05 0.044,0.063 0.044,0.063 l 1.514,0 C 0.038,0.958 0.394,0.87 0.394,0.463 0.394,0.056 0,0 0,0 m 2.178,-1.79 c -0.45,0.002 -0.482,0.181 -0.482,0.207 0,0.046 0.056,0.075 0.056,0.075 0.169,0.081 0.514,0.35 0.514,0.35 0.732,0.57 0.82,1.352 0.82,1.771 0,0.42 -0.063,1.163 -0.814,1.814 C 1.521,3.078 0.57,3.098 0.57,3.098 l -5.287,0 c 0,0 0,-7.522 0,-7.524 0,-0.024 0.022,-0.043 0.046,-0.043 0.005,0 2.943,0 2.943,0 l 0,2.109 c 0,0.038 0.057,0 0.057,0 l 1.533,-1.539 c 0.545,-0.551 1.446,-0.57 1.446,-0.57 l 4.525,0 0,2.679 -3.655,0 z" />_x000D_
        </g>_x000D_
        <g transform="matrix(12.997776,0,0,-12.997776,466.86346,556.40203)">_x000D_
            <path d="m 0,0 -1.107,0 c -0.041,0 -0.067,0.044 -0.067,0.086 0,0.016 0.589,1.914 0.589,1.914 0.021,0.071 0.027,0.073 0.031,0.073 l 0.001,0 c 0.004,0 0.01,-0.002 0.031,-0.073 0,0 0.589,-1.898 0.589,-1.914 C 0.067,0.044 0.04,0 0,0 M 1.49,4.347 C 1.479,4.385 1.446,4.412 1.405,4.414 l -4.065,0 C -2.7,4.412 -2.734,4.385 -2.745,4.348 c 0,0 -2.245,-7.42 -2.245,-7.434 0,-0.037 0.03,-0.067 0.067,-0.067 l 2.687,0 c 0.022,0.007 0.038,0.028 0.043,0.051 l 0.313,1.001 c 0.01,0.024 0.033,0.041 0.061,0.042 l 2.478,0 C 0.687,-2.061 0.71,-2.078 0.721,-2.102 l 0.32,-1 c 0.005,-0.023 0.021,-0.044 0.042,-0.052 0,0 2.642,10e-4 2.644,10e-4 0.037,0 0.067,0.028 0.067,0.066 0,0.012 -2.304,7.434 -2.304,7.434" />_x000D_
        </g>_x000D_
    </g>_x000D_
  </defs>_x000D_
  <rect style="fill:#8AB" width="364" height="172" />_x000D_
  <use style="fill:white;" filter="url(#Blur)" xlink:href="#Img"_x000D_
    transform="translate(1.8,.9)"/>_x000D_
  <use style="fill:black;" xlink:href="#Img"/>_x000D_
</svg>
_x000D_
_x000D_
_x000D_

Set font-weight using Bootstrap classes

EDIT 2 (final) : According to the bootstrap 4 documentation, class="font-weight-bold" is what you are looking for.


EDIT : You can use class="font-weight-bold" as shown here (Bootstrap 4 alpha).

I kept the original answer below for clarity purposes.


I am posting this answer because this thread seems to have a lot of visitors, yet it had no proper solution to solve this issue. But there will be soon now a way with Bootstrap 4 :

As this GitHub pull request shows, you will just have to use the text-weight-normal, text-weight-bold and text-weight-italic classes.

This can maybe change until the official stable release. At this date of writing, this pull request is not merged yet in the alpha branch.

I will update this post once Bootstrap v4 has been released.

Google Maps API v3: How do I dynamically change the marker icon?

You can try this code

    <script src="http://maps.googleapis.com/maps/api/js"></script>
<script type="text/javascript" src="http://google-maps-utility-library-v3.googlecode.com/svn/trunk/infobox/src/infobox.js"></script>

<script>

    function initialize()
    {
        var map;
        var bounds = new google.maps.LatLngBounds();
        var mapOptions = {
                            zoom: 10,
                            mapTypeId: google.maps.MapTypeId.ROADMAP    
                         };
        map = new google.maps.Map(document.getElementById("mapDiv"), mapOptions);
        var markers = [
            ['title-1', '<img style="width:100%;" src="canberra_hero_image.jpg"></img>', 51.508742, -0.120850, '<p> Hello - 1 </p>'],
            ['title-2', '<img style="width:100%;" src="canberra_hero_image.jpg"></img>', 51.508742, -0.420850, '<p> Hello - 2 </p>'],
            ['title-3', '<img style="width:100%;" src="canberra_hero_image.jpg"></img>', 51.508742, -0.720850, '<p> Hello - 3 </p>'],
            ['title-4', '<img style="width:100%;" src="canberra_hero_image.jpg"></img>', 51.508742, -1.020850, '<p> Hello - 4 </p>'],
            ['title-5', '<img style="width:100%;" src="canberra_hero_image.jpg"></img>', 51.508742, -1.320850, '<p> Hello - 5 </p>']
        ];

        var infoWindow = new google.maps.InfoWindow(), marker, i;
        var testMarker = [];
        var status = [];
        for( i = 0; i < markers.length; i++ ) 
        {
            var title = markers[i][0];
            var loan = markers[i][1];
            var lat = markers[i][2];
            var long = markers[i][3];
            var add = markers[i][4];


            var iconGreen = 'img/greenMarker.png'; //green marker
            var iconRed = 'img/redMarker.png';     //red marker

            var infoWindowContent = loan + "\n" + placeId + add;

            var position = new google.maps.LatLng(lat, long);
            bounds.extend(position);

            marker = new google.maps.Marker({
                map: map,
                title: title,
                position: position,
                icon: iconGreen
            });
            testMarker[i] = marker;
            status[i] = 1;
            google.maps.event.addListener(marker, 'click', ( function toggleBounce( i,status,testMarker) 
            {
                return function() 
                {
                    infoWindow.setContent(markers[i][1]+markers[i][4]);
                    if( status[i] === 1 )
                    {
                        testMarker[i].setIcon(iconRed);
                        status[i] = 0;

                    }
                    for( var k = 0; k <  markers.length ; k++ )
                    {
                        if(k != i)
                        {
                            testMarker[k].setIcon(iconGreen);
                            status[i] = 1;

                        }
                    }
                    infoWindow.open(map, testMarker[i]);
                }
            })( i,status,testMarker));
            map.fitBounds(bounds);
        }
        var boundsListener = google.maps.event.addListener((map), 'bounds_changed', function(event)
        {
            this.setZoom(8);
            google.maps.event.removeListener(boundsListener);
        });
    }
    google.maps.event.addDomListener(window, 'load', initialize);

</script>

<div id="mapDiv" style="width:820px; height:300px"></div>

embedding image in html email

The other solution is attaching the image as attachment and then referencing it html code using cid.

HTML Code:

<html>
    <head>
    </head>
    <body>
        <img width=100 height=100 id="1" src="cid:Logo.jpg">
    </body>
</html>

C# Code:

EmailMessage email = new EmailMessage(service);
email.Subject = "Email with Image";
email.Body = new MessageBody(BodyType.HTML, html);
email.ToRecipients.Add("[email protected]");
string file = @"C:\Users\acv\Pictures\Logo.jpg";
email.Attachments.AddFileAttachment("Logo.jpg", file);
email.Attachments[0].IsInline = true;
email.Attachments[0].ContentId = "Logo.jpg";
email.SendAndSaveCopy();

How to pass a form input value into a JavaScript function

There are several ways to approach this. Personally, I would avoid in-line scripting. Since you've tagged jQuery, let's use that.

HTML:

<form>
    <input type="text" id="formValueId" name="valueId"/>
    <input type="button" id="myButton" />
</form>

JavaScript:

$(document).ready(function() {
    $('#myButton').click(function() {
      foo($('#formValueId').val());
    });
});

SQL Server query to find all permissions/access for all users in a database

CREATE PROCEDURE Get_permission 
AS 
    DECLARE @db_name  VARCHAR(200), 
            @sql_text VARCHAR(max) 

    SET @sql_text='Create table ##db_name (user_name varchar(max),' 

    DECLARE db_cursor CURSOR FOR 
      SELECT name 
      FROM   sys.databases 

    OPEN db_cursor 

    FETCH next FROM db_cursor INTO @db_name 

    WHILE @@FETCH_STATUS = 0 
      BEGIN 
          SET @sql_text=@sql_text + @db_name + ' varchar(max),' 

          FETCH next FROM db_cursor INTO @db_name 
      END 

    CLOSE db_cursor 

    SET @sql_text=@sql_text + 'Server_perm varchar(max))' 

    EXEC (@sql_text) 

    DEALLOCATE db_cursor 

    DECLARE @RoleName VARCHAR(50) 
    DECLARE @UserName VARCHAR(50) 
    DECLARE @CMD VARCHAR(1000) 

    CREATE TABLE #permission 
      ( 
         user_name    VARCHAR(50), 
         databasename VARCHAR(50), 
         role         VARCHAR(50) 
      ) 

    DECLARE longspcur CURSOR FOR 
      SELECT name 
      FROM   sys.server_principals 
      WHERE  type IN ( 'S', 'U', 'G' ) 
             AND principal_id > 4 
             AND name NOT LIKE '##%' 
             AND name <> 'NT AUTHORITY\SYSTEM' 
             AND name <> 'ONDEMAND\Administrator' 
             AND name NOT LIKE 'steel%' 

    OPEN longspcur 

    FETCH next FROM longspcur INTO @UserName 

    WHILE @@FETCH_STATUS = 0 
      BEGIN 
          CREATE TABLE #userroles_kk 
            ( 
               databasename VARCHAR(50), 
               role         VARCHAR(50) 
            ) 

          CREATE TABLE #rolemember_kk 
            ( 
               dbrole     VARCHAR(100), 
               membername VARCHAR(100), 
               membersid  VARBINARY(2048) 
            ) 

          SET @CMD = 'use ? truncate table #RoleMember_kk insert into #RoleMember_kk exec sp_helprolemember  insert into #UserRoles_kk (DatabaseName, Role) select db_name(), dbRole from #RoleMember_kk where MemberName = ''' + @UserName + '''' 

          EXEC Sp_msforeachdb 
            @CMD 

          INSERT INTO #permission 
          SELECT @UserName 'user', 
                 b.name, 
                 u.role 
          FROM   sys.sysdatabases b 
                 LEFT OUTER JOIN #userroles_kk u 
                              ON u.databasename = b.name --and u.Role='db_owner' 
          ORDER  BY 1 

          DROP TABLE #userroles_kk; 

          DROP TABLE #rolemember_kk; 

          FETCH next FROM longspcur INTO @UserName 
      END 

    CLOSE longspcur 

    DEALLOCATE longspcur 

    TRUNCATE TABLE ##db_name 

    DECLARE @d1 VARCHAR(max), 
            @d2 VARCHAR(max), 
            @d3 VARCHAR(max), 
            @ss VARCHAR(max) 
    DECLARE perm_cur CURSOR FOR 
      SELECT * 
      FROM   #permission 
      ORDER  BY 2 DESC 

    OPEN perm_cur 

    FETCH next FROM perm_cur INTO @d1, @d2, @d3 

    WHILE @@FETCH_STATUS = 0 
      BEGIN 
          IF NOT EXISTS(SELECT 1 
                        FROM   ##db_name 
                        WHERE  user_name = @d1) 
            BEGIN 
                SET @ss='insert into ##db_name(user_name) values (''' 
                        + @d1 + ''')' 

                EXEC (@ss) 

                SET @ss='update ##db_name set ' + @d2 + '=''' + @d3 
                        + ''' where user_name=''' + @d1 + '''' 

                EXEC (@ss) 
            END 
          ELSE 
            BEGIN 
                DECLARE @var            NVARCHAR(max), 
                        @ParmDefinition NVARCHAR(max), 
                        @var1           NVARCHAR(max) 

                SET @var = N'select @var1=' + @d2 
                           + ' from ##db_name where USER_NAME=''' + @d1 
                           + ''''; 
                SET @ParmDefinition = N'@var1 nvarchar(300) OUTPUT'; 

                EXECUTE Sp_executesql 
                  @var, 
                  @ParmDefinition, 
                  @var1=@var1 output; 

                SET @var1=Isnull(@var1, ' ') 
                SET @var= '  update ##db_name set ' + @d2 + '=''' + @var1 + ' ' 
                          + @d3 + ''' where user_name=''' + @d1 + '''  ' 

                EXEC (@var) 
            END 

          FETCH next FROM perm_cur INTO @d1, @d2, @d3 
      END 

    CLOSE perm_cur 

    DEALLOCATE perm_cur 

    SELECT * 
    FROM   ##db_name 

    DROP TABLE ##db_name 

    DROP TABLE #permission 

Operation must use an updatable query. (Error 3073) Microsoft Access

I had a similar problem where the following queries wouldn't work;

update tbl_Lot_Valuation_Details as LVD
set LVD.LGAName = (select LGA.LGA_NAME from tbl_Prop_LGA as LGA where LGA.LGA_CODE = LVD.LGCode)
where LVD.LGAName is null;

update tbl_LOT_VALUATION_DETAILS inner join tbl_prop_LGA on tbl_LOT_VALUATION_DETAILS.LGCode = tbl_prop_LGA.LGA_CODE 
set tbl_LOT_VALUATION_DETAILS.LGAName = [tbl_Prop_LGA].[LGA_NAME]
where tbl_LOT_VALUATION_DETAILS.LGAName is null;

However using DLookup resolved the problem;

update tbl_Lot_Valuation_Details as LVD
set LVD.LGAName = dlookup("LGA_NAME", "tbl_Prop_LGA", "LGA_CODE="+LVD.LGCode)
where LVD.LGAName is null;

This solution was originally proposed at https://stackoverflow.com/questions/537161/sql-update-woes-in-ms-access-operation-must-use-an-updateable-query

How to create an installer for a .net Windows Service using Visual Studio

InstallUtil classes ( ServiceInstaller ) are considered an anti-pattern by the Windows Installer community. It's a fragile, out of process, reinventing of the wheel that ignores the fact that Windows Installer has built-in support for Services.

Visual Studio deployment projects ( also not highly regarded and deprecated in the next release of Visual Studio ) do not have native support for services. But they can consume merge modules. So I would take a look at this blog article to understand how to create a merge module using Windows Installer XML that can express the service and then consume that merge module in your VDPROJ solution.

Augmenting InstallShield using Windows Installer XML - Windows Services

IsWiX Windows Service Tutorial

IsWiX Windows Service Video

How to get Real IP from Visitor?

This is my approach:

 function getRealUserIp(){
    switch(true){
      case (!empty($_SERVER['HTTP_X_REAL_IP'])) : return $_SERVER['HTTP_X_REAL_IP'];
      case (!empty($_SERVER['HTTP_CLIENT_IP'])) : return $_SERVER['HTTP_CLIENT_IP'];
      case (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) : return $_SERVER['HTTP_X_FORWARDED_FOR'];
      default : return $_SERVER['REMOTE_ADDR'];
    }
 }

How to use:

$ip = getRealUserIp();

Get all Attributes from a HTML element with Javascript/jQuery

Imagine you've got an HTML element like below:

<a class="toc-item"
   href="/books/n/ukhta2333/s5/"
   id="book-link-29"
>
   Chapter 5. Conclusions and recommendations
</a>

One way you can get all attributes of it is to convert them into an array:

const el = document.getElementById("book-link-29")
const attrArray = Array.from(el.attributes)

// Now you can iterate all the attributes and do whatever you need.
const attributes = attrArray.reduce((attrs, attr) => {
    attrs !== '' && (attrs += ' ')
    attrs += `${attr.nodeName}="${attr.nodeValue}"`
    return attrs
}, '')
console.log(attributes)

And below is the string that what you'll get (from the example), which includes all attributes:

class="toc-item" href="/books/n/ukhta2333/s5/" id="book-link-29"

Add new field to every document in a MongoDB collection

Same as the updating existing collection field, $set will add a new fields if the specified field does not exist.

Check out this example:

> db.foo.find()
> db.foo.insert({"test":"a"})
> db.foo.find()
{ "_id" : ObjectId("4e93037bbf6f1dd3a0a9541a"), "test" : "a" }
> item = db.foo.findOne()
{ "_id" : ObjectId("4e93037bbf6f1dd3a0a9541a"), "test" : "a" }
> db.foo.update({"_id" :ObjectId("4e93037bbf6f1dd3a0a9541a") },{$set : {"new_field":1}})
> db.foo.find()
{ "_id" : ObjectId("4e93037bbf6f1dd3a0a9541a"), "new_field" : 1, "test" : "a" }

EDIT:

In case you want to add a new_field to all your collection, you have to use empty selector, and set multi flag to true (last param) to update all the documents

db.your_collection.update(
  {},
  { $set: {"new_field": 1} },
  false,
  true
)

EDIT:

In the above example last 2 fields false, true specifies the upsert and multi flags.

Upsert: If set to true, creates a new document when no document matches the query criteria.

Multi: If set to true, updates multiple documents that meet the query criteria. If set to false, updates one document.

This is for Mongo versions prior to 2.2. For latest versions the query is changed a bit

db.your_collection.update({},
                          {$set : {"new_field":1}},
                          {upsert:false,
                          multi:true}) 

SSH SCP Local file to Remote in Terminal Mac Os X

Just to clarify the answer given by JScoobyCed, the scp command cannot copy files to directories that require administrative permission. However, you can use the scp command to copy to directories that belong to the remote user.

So, to copy to a directory that requires root privileges, you must first copy that file to a directory belonging to the remote user using the scp command. Next, you must login to the remote account using ssh. Once logged in, you can then move the file to the directory of your choosing by using the sudo mv command. In short, the commands to use are as follows:

Using scp, copy file to a directory in the remote user's account, for example the Documents directory:

scp /path/to/your/local/file remoteUser@some_address:/home/remoteUser/Documents

Next, login to the remote user's account using ssh and then move the file to a restricted directory using sudo:

ssh remoteUser@some_address
sudo mv /home/remoteUser/Documents/file /var/www

Matplotlib: Specify format of floats for tick labels

format labels using lambda function

enter image description here 3x the same plot with differnt y-labeling

Minimal example

import numpy as np
import matplotlib as mpl
import matplotlib.pylab as plt
from matplotlib.ticker import FormatStrFormatter

fig, axs = mpl.pylab.subplots(1, 3)

xs = np.arange(10)
ys = 1 + xs ** 2 * 1e-3

axs[0].set_title('default y-labeling')
axs[0].scatter(xs, ys)
axs[1].set_title('custom y-labeling')
axs[1].scatter(xs, ys)
axs[2].set_title('x, pos arguments')
axs[2].scatter(xs, ys)


fmt = lambda x, pos: '1+ {:.0f}e-3'.format((x-1)*1e3, pos)
axs[1].yaxis.set_major_formatter(mpl.ticker.FuncFormatter(fmt))

fmt = lambda x, pos: 'x={:f}\npos={:f}'.format(x, pos)
axs[2].yaxis.set_major_formatter(mpl.ticker.FuncFormatter(fmt))

You can also use 'real'-functions instead of lambdas, of course. https://matplotlib.org/3.1.1/gallery/ticks_and_spines/tick-formatters.html

How to call external JavaScript function in HTML

If a <script> has a src then the text content of the element will be not be executed as JS (although it will appear in the DOM).

You need to use multiple script elements.

  1. a <script> to load the external script
  2. a <script> to hold your inline code (with the call to the function in the external script)

    scroll_messages();

WCF Exception: Could not find a base address that matches scheme http for the endpoint

You can get this if you ONLY configure https as a site binding inside IIS.

You need to add http(80) as well as https(443) - at least I did :-)

How to fix '.' is not an internal or external command error

Just leave out the "dot-slash" ./:

D:\Gesture Recognition\Gesture Recognition\Debug>"Gesture Recognition.exe"

Though, if you wanted to, you could use .\ and it would work.

D:\Gesture Recognition\Gesture Recognition\Debug>.\"Gesture Recognition.exe"

Maven is not working in Java 8 when Javadoc tags are incomplete

In my case I was using a parent pom (not sure it was the real cause since I was running against the clock), maven 2.x and java 1.6 were used, for some reason above solutions didn't work, so I added the following profile and managed it to make it run:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.mycompany</groupId>
    <artifactId>myapp</artifactId>
    <packaging>war</packaging>
    <name>myapp</name>
    <version>0.0.1-SNAPSHOT</version>
    <description>My App</description>
    <parent>
        <groupId>com.mycompany</groupId>
        <artifactId>parent-artifact</artifactId>
        <version>0.0.1</version>
    </parent>

    <profiles>
        <profile>
            <id>doclint-java6-disable</id>
            <activation>
                <jdk>[1.6,)</jdk>
            </activation>
            <properties>
                <additionalparam>--allow-script-in-comments</additionalparam>
            </properties>
        </profile>
    </profiles>
</project>

Verify if file exists or not in C#

You can determine whether a specified file exists using the Exists method of the File class in the System.IO namespace:

bool System.IO.File.Exists(string path)

You can find the documentation here on MSDN.

Example:

using System;
using System.IO;

class Test
{
    public static void Main()
    {
        string resumeFile = @"c:\ResumesArchive\923823.txt";
        string newFile = @"c:\ResumesImport\newResume.txt";
        if (File.Exists(resumeFile))
        {
            File.Copy(resumeFile, newFile);
        }
        else
        {
            Console.WriteLine("Resume file does not exist.");
        }
    }
}

How can I disable ARC for a single file in a project?

It is possible to disable ARC (Automatic Reference Counting) for particular file in Xcode.

Select Target -> Build Phases -> Compile Sources -> Select File (double click) -> Add "-fno-objc-arc" to pop-up window.

I had encountered this situation in using "Reachibility" files.

This is shown in below figure :

enter image description here

How do I add a border to an image in HTML?

as said above simple line of code will fix your problems

border: 1px solid #000;

There is another option to add border to your image and that with photoshop you can see how it's done with this tutorial below: http://bannercheapdesign.com/articles-and-tutorials/learn-how-to-add-border-to-your-banner-design-using-photoshop/

Converting a value to 2 decimal places within jQuery

You need to use the .toFixed() method

It takes as a parameter the number of digits to show after the decimal point.

$(document).ready(function() {
  $('.add').click(function() {
     var value = parseFloat($('#total').text()) + parseFloat($(this).data('amount'))/100
     $('#total').text( value.toFixed(2) );
  });
})

Quick Way to Implement Dictionary in C

Additionally, you can use Google CityHash:

#include <stdlib.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>

#include <byteswap.h>

#include "city.h"

void swap(uint32* a, uint32* b) {
    int temp = *a;
    *a = *b;
    *b = temp;
}

#define PERMUTE3(a, b, c) swap(&a, &b); swap(&a, &c);

// Magic numbers for 32-bit hashing.  Copied from Murmur3.
static const uint32 c1 = 0xcc9e2d51;
static const uint32 c2 = 0x1b873593;

static uint32 UNALIGNED_LOAD32(const char *p) {
  uint32 result;
  memcpy(&result, p, sizeof(result));
  return result;
}

static uint32 Fetch32(const char *p) {
  return UNALIGNED_LOAD32(p);
}

// A 32-bit to 32-bit integer hash copied from Murmur3.
static uint32 fmix(uint32 h)
{
  h ^= h >> 16;
  h *= 0x85ebca6b;
  h ^= h >> 13;
  h *= 0xc2b2ae35;
  h ^= h >> 16;
  return h;
}

static uint32 Rotate32(uint32 val, int shift) {
  // Avoid shifting by 32: doing so yields an undefined result.
  return shift == 0 ? val : ((val >> shift) | (val << (32 - shift)));
}

static uint32 Mur(uint32 a, uint32 h) {
  // Helper from Murmur3 for combining two 32-bit values.
  a *= c1;
  a = Rotate32(a, 17);
  a *= c2;
  h ^= a;
  h = Rotate32(h, 19);
  return h * 5 + 0xe6546b64;
}

static uint32 Hash32Len13to24(const char *s, size_t len) {
  uint32 a = Fetch32(s - 4 + (len >> 1));
  uint32 b = Fetch32(s + 4);
  uint32 c = Fetch32(s + len - 8);
  uint32 d = Fetch32(s + (len >> 1));
  uint32 e = Fetch32(s);
  uint32 f = Fetch32(s + len - 4);
  uint32 h = len;

  return fmix(Mur(f, Mur(e, Mur(d, Mur(c, Mur(b, Mur(a, h)))))));
}

static uint32 Hash32Len0to4(const char *s, size_t len) {
  uint32 b = 0;
  uint32 c = 9;
  for (size_t i = 0; i < len; i++) {
    signed char v = s[i];
    b = b * c1 + v;
    c ^= b;
  }
  return fmix(Mur(b, Mur(len, c)));
}

static uint32 Hash32Len5to12(const char *s, size_t len) {
  uint32 a = len, b = len * 5, c = 9, d = b;
  a += Fetch32(s);
  b += Fetch32(s + len - 4);
  c += Fetch32(s + ((len >> 1) & 4));
  return fmix(Mur(c, Mur(b, Mur(a, d))));
}

uint32 CityHash32(const char *s, size_t len) {
  if (len <= 24) {
    return len <= 12 ?
        (len <= 4 ? Hash32Len0to4(s, len) : Hash32Len5to12(s, len)) :
        Hash32Len13to24(s, len);
  }

  // len > 24
  uint32 h = len, g = c1 * len, f = g;
  uint32 a0 = Rotate32(Fetch32(s + len - 4) * c1, 17) * c2;
  uint32 a1 = Rotate32(Fetch32(s + len - 8) * c1, 17) * c2;
  uint32 a2 = Rotate32(Fetch32(s + len - 16) * c1, 17) * c2;
  uint32 a3 = Rotate32(Fetch32(s + len - 12) * c1, 17) * c2;
  uint32 a4 = Rotate32(Fetch32(s + len - 20) * c1, 17) * c2;
  h ^= a0;
  h = Rotate32(h, 19);
  h = h * 5 + 0xe6546b64;
  h ^= a2;
  h = Rotate32(h, 19);
  h = h * 5 + 0xe6546b64;
  g ^= a1;
  g = Rotate32(g, 19);
  g = g * 5 + 0xe6546b64;
  g ^= a3;
  g = Rotate32(g, 19);
  g = g * 5 + 0xe6546b64;
  f += a4;
  f = Rotate32(f, 19);
  f = f * 5 + 0xe6546b64;
  size_t iters = (len - 1) / 20;
  do {
    uint32 a0 = Rotate32(Fetch32(s) * c1, 17) * c2;
    uint32 a1 = Fetch32(s + 4);
    uint32 a2 = Rotate32(Fetch32(s + 8) * c1, 17) * c2;
    uint32 a3 = Rotate32(Fetch32(s + 12) * c1, 17) * c2;
    uint32 a4 = Fetch32(s + 16);
    h ^= a0;
    h = Rotate32(h, 18);
    h = h * 5 + 0xe6546b64;
    f += a1;
    f = Rotate32(f, 19);
    f = f * c1;
    g += a2;
    g = Rotate32(g, 18);
    g = g * 5 + 0xe6546b64;
    h ^= a3 + a1;
    h = Rotate32(h, 19);
    h = h * 5 + 0xe6546b64;
    g ^= a4;
    g = bswap_32(g) * 5;
    h += a4 * 5;
    h = bswap_32(h);
    f += a0;
    PERMUTE3(f, h, g);
    s += 20;
  } while (--iters != 0);
  g = Rotate32(g, 11) * c1;
  g = Rotate32(g, 17) * c1;
  f = Rotate32(f, 11) * c1;
  f = Rotate32(f, 17) * c1;
  h = Rotate32(h + g, 19);
  h = h * 5 + 0xe6546b64;
  h = Rotate32(h, 17) * c1;
  h = Rotate32(h + f, 19);
  h = h * 5 + 0xe6546b64;
  h = Rotate32(h, 17) * c1;
  return h;
}

Excel Formula: Count cells where value is date

This is difficult with worksheet functions because dates in excel are simply formatted numbers - only CELL function lets you investigate the format of a cell (and you can't apply that to a range, so a helper column would be required).......or, if you only have dates and blanks.....or dates and text then it would be sufficient to use COUNT function, i.e.

=COUNT(range)

That counts numbers so it won't be adequate if you want to distinguish dates from numbers. If you do then the number range could be utilised, e.g. if you have numbers in a range and dates but the numbers will all be lower than 10,000 and the dates will all be relatively recent then you could use this version to exclude the numbers

=COUNTIF(range,">10000")

WCF Error - Could not find default endpoint element that references contract 'UserService.UserService'

I ran into the same issue, for whatever reason Visual Studio did not update the web config when I first added the service. I found that updating the Service Reference also fixed this issue.

Steps:

  1. Navigate to the Service Reference Folder
  2. Expand it
  3. Right Click and Select update Service Reference
  4. Observe web Config be updated

Git add and commit in one command

You can use git aliases, e.g.

git config --global alias.add-commit '!git add -A && git commit'

and use it with

git add-commit -m 'My commit message'

EDIT: Reverted back to ticks ('), as otherwise it will fail for shell expansion on Linux. On Windows, one should use double-quotes (") instead (pointed out in the comments, did not verify).

SQL Query Where Field DOES NOT Contain $x

SELECT * FROM table WHERE field1 NOT LIKE '%$x%'; (Make sure you escape $x properly beforehand to avoid SQL injection)

Edit: NOT IN does something a bit different - your question isn't totally clear so pick which one to use. LIKE 'xxx%' can use an index. LIKE '%xxx' or LIKE '%xxx%' can't.

How to simplify a null-safe compareTo() implementation?

I was looking for something similar and this seemed a bit complicated so I did this. I think it's a little easier to understand. You can use it as a Comparator or as a one liner. For this question you would change to compareToIgnoreCase(). As is, nulls float up. You can flip the 1, -1 if you want them to sink.

StringUtil.NULL_SAFE_COMPARATOR.compare(getName(), o.getName());

.

public class StringUtil {
    public static final Comparator<String> NULL_SAFE_COMPARATOR = new Comparator<String>() {

        @Override
        public int compare(final String s1, final String s2) {
            if (s1 == s2) {
                //Nulls or exact equality
                return 0;
            } else if (s1 == null) {
                //s1 null and s2 not null, so s1 less
                return -1;
            } else if (s2 == null) {
                //s2 null and s1 not null, so s1 greater
                return 1;
            } else {
                return s1.compareTo(s2);
            }
        }
    }; 

    public static void main(String args[]) {
        final ArrayList<String> list = new ArrayList<String>(Arrays.asList(new String[]{"qad", "bad", "sad", null, "had"}));
        Collections.sort(list, NULL_SAFE_COMPARATOR);

        System.out.println(list);
    }
}

How to merge two arrays of objects by ID using lodash?

Create dictionaries for both arrays using _.keyBy(), merge the dictionaries, and convert the result to an array with _.values(). In this way, the order of the arrays doesn't matter. In addition, it can also handle arrays of different length.

_x000D_
_x000D_
const ObjectId = (id) => id; // mock of ObjectId_x000D_
const arr1 = [{"member" : ObjectId("57989cbe54cf5d2ce83ff9d8"),"bank" : ObjectId("575b052ca6f66a5732749ecc"),"country" : ObjectId("575b0523a6f66a5732749ecb")},{"member" : ObjectId("57989cbe54cf5d2ce83ff9d6"),"bank" : ObjectId("575b052ca6f66a5732749ecc"),"country" : ObjectId("575b0523a6f66a5732749ecb")}];_x000D_
const arr2 = [{"member" : ObjectId("57989cbe54cf5d2ce83ff9d6"),"name" : 'xxxxxx',"age" : 25},{"member" : ObjectId("57989cbe54cf5d2ce83ff9d8"),"name" : 'yyyyyyyyyy',"age" : 26}];_x000D_
_x000D_
const merged = _(arr1) // start sequence_x000D_
  .keyBy('member') // create a dictionary of the 1st array_x000D_
  .merge(_.keyBy(arr2, 'member')) // create a dictionary of the 2nd array, and merge it to the 1st_x000D_
  .values() // turn the combined dictionary to array_x000D_
  .value(); // get the value (array) out of the sequence_x000D_
_x000D_
console.log(merged);
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.14.0/lodash.min.js"></script>
_x000D_
_x000D_
_x000D_

Using ES6 Map

Concat the arrays, and reduce the combined array to a Map. Use Object#assign to combine objects with the same member to a new object, and store in map. Convert the map to an array with Map#values and spread:

_x000D_
_x000D_
const ObjectId = (id) => id; // mock of ObjectId_x000D_
const arr1 = [{"member" : ObjectId("57989cbe54cf5d2ce83ff9d8"),"bank" : ObjectId("575b052ca6f66a5732749ecc"),"country" : ObjectId("575b0523a6f66a5732749ecb")},{"member" : ObjectId("57989cbe54cf5d2ce83ff9d6"),"bank" : ObjectId("575b052ca6f66a5732749ecc"),"country" : ObjectId("575b0523a6f66a5732749ecb")}];_x000D_
const arr2 = [{"member" : ObjectId("57989cbe54cf5d2ce83ff9d6"),"name" : 'xxxxxx',"age" : 25},{"member" : ObjectId("57989cbe54cf5d2ce83ff9d8"),"name" : 'yyyyyyyyyy',"age" : 26}];_x000D_
_x000D_
const merged = [...arr1.concat(arr2).reduce((m, o) => _x000D_
  m.set(o.member, Object.assign(m.get(o.member) || {}, o))_x000D_
, new Map()).values()];_x000D_
_x000D_
console.log(merged);
_x000D_
_x000D_
_x000D_

Unable to copy a file from obj\Debug to bin\Debug

Solution1:

  1. Close the project.
  2. Delete the bin folder.
  3. Open the project.
  4. Build the project.

Solution2:

Add the following code in pre-build event:

attrib -r $(OutDir)*..\* /s

This command line code will remove the ready-only attribute of "bin" folder. Now visual studio can easily delete and copy new dlls.

Changing variable names with Python for loops

You could access your class's __dict__ attribute:

for i in range(3)
     self.__dict__['group%d' % i]=self.getGroup(selected, header+i)

But why can't you just use an array named group?

How to modify WooCommerce cart, checkout pages (main theme portion)

You can use function: wc_get_page_id( 'cart' ) to get the ID of the page. This function will use the page setup as 'cart' page and not the slug. Meaning it will keep working also when you setup a different url for your 'cart' on the settings page. This works for all kind of Woocommerce special page, like 'checkout', 'shop' etc.

example:

if (wc_get_page_id( 'cart' ) == get_the_ID()) {
  // Do something.
}

Find document with array that contains a specific value

In case you need to find documents which contain NULL elements inside an array of sub-documents, I've found this query which works pretty well:

db.collection.find({"keyWithArray":{$elemMatch:{"$in":[null], "$exists":true}}})

This query is taken from this post: MongoDb query array with null values

It was a great find and it works much better than my own initial and wrong version (which turned out to work fine only for arrays with one element):

.find({
    'MyArrayOfSubDocuments': { $not: { $size: 0 } },
    'MyArrayOfSubDocuments._id': { $exists: false }
})

Creating Accordion Table with Bootstrap

In the accepted answer you get annoying spacing between the visible rows when the expandable row is hidden. You can get rid of that by adding this to css:

.collapse-row.collapsed + tr {
     display: none;
}

'+' is adjacent sibling selector, so if you want your expandable row to be the next row, this selects the next tr following tr named collapse-row.

Here is updated fiddle: http://jsfiddle.net/Nb7wy/2372/

ImportError: cannot import name NUMPY_MKL

I'm not sure if this is a good solution but it removed the error. I commented out the line:

from numpy._distributor_init import NUMPY_MKL 

and it worked. Not sure if this will cause other features to break though

How to add an item to a drop down list in ASP.NET?

Try this, it will insert the list item at index 0;

DropDownList1.Items.Insert(0, new ListItem("Add New", ""));

New line character in VB.Net?

You need to use HTML on a web page to get line breaks. For example "<br/>" will give you a line break.

How to debug .htaccess RewriteRule not working

Enter some junk value into your .htaccess e.g. foo bar, sakjnaskljdnas any keyword not recognized by htaccess and visit your URL. If it is working, you should get a

500 Internal Server Error

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request....

I suggest you to put it soon after RewriteEngine on.


Since you are on your machine. I presume you have access to apache .conf file.

open the .conf file, and look for a line similar to:

LoadModule rewrite_module modules/mod_rewrite.so

If it is commented(#), uncomment and restart apache.


To log rewrite

RewriteEngine On
RewriteLog "/path/to/rewrite.log"
RewriteLogLevel 9

Put the above 3 lines in your virtualhost. restart the httpd.

RewriteLogLevel 9 Using a high value for Level will slow down your Apache server dramatically! Use the rewriting logfile at a Level greater than 2 only for debugging! Level 9 will log almost every rewritelog detail.


UPDATE

Things have changed in Apache 2.4:

FROM Upgrading to 2.4 from 2.2

The RewriteLog and RewriteLogLevel directives have been removed. This functionality is now provided by configuring the appropriate level of logging for the mod_rewrite module using the LogLevel directive. See also the mod_rewrite logging section.

For more on LogLevel, refer LogLevel Directive

you can accomplish

RewriteLog "/path/to/rewrite.log"

in this manner now

LogLevel debug rewrite_module:debug

How to detect incoming calls, in an Android device?

Here's what I use to do this:

Manifest:

<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.PROCESS_OUTGOING_CALLS"/>

<!--This part is inside the application-->
    <receiver android:name=".CallReceiver" >
        <intent-filter>
            <action android:name="android.intent.action.PHONE_STATE" />
        </intent-filter>
        <intent-filter>
            <action android:name="android.intent.action.NEW_OUTGOING_CALL" />
        </intent-filter>
    </receiver>

My base reusable call detector

package com.gabesechan.android.reusable.receivers;

import java.util.Date;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.telephony.TelephonyManager;

public abstract class PhonecallReceiver extends BroadcastReceiver {

    //The receiver will be recreated whenever android feels like it.  We need a static variable to remember data between instantiations

    private static int lastState = TelephonyManager.CALL_STATE_IDLE;
    private static Date callStartTime;
    private static boolean isIncoming;
    private static String savedNumber;  //because the passed incoming is only valid in ringing


    @Override
    public void onReceive(Context context, Intent intent) {

        //We listen to two intents.  The new outgoing call only tells us of an outgoing call.  We use it to get the number.
        if (intent.getAction().equals("android.intent.action.NEW_OUTGOING_CALL")) {
            savedNumber = intent.getExtras().getString("android.intent.extra.PHONE_NUMBER");
        }
        else{
            String stateStr = intent.getExtras().getString(TelephonyManager.EXTRA_STATE);
            String number = intent.getExtras().getString(TelephonyManager.EXTRA_INCOMING_NUMBER);
            int state = 0;
            if(stateStr.equals(TelephonyManager.EXTRA_STATE_IDLE)){
                state = TelephonyManager.CALL_STATE_IDLE;
            }
            else if(stateStr.equals(TelephonyManager.EXTRA_STATE_OFFHOOK)){
                state = TelephonyManager.CALL_STATE_OFFHOOK;
            }
            else if(stateStr.equals(TelephonyManager.EXTRA_STATE_RINGING)){
                state = TelephonyManager.CALL_STATE_RINGING;
            }


            onCallStateChanged(context, state, number);
        }
    }

    //Derived classes should override these to respond to specific events of interest
    protected abstract void onIncomingCallReceived(Context ctx, String number, Date start);
    protected abstract void onIncomingCallAnswered(Context ctx, String number, Date start);
    protected abstract void onIncomingCallEnded(Context ctx, String number, Date start, Date end);

    protected abstract void onOutgoingCallStarted(Context ctx, String number, Date start);      
    protected abstract void onOutgoingCallEnded(Context ctx, String number, Date start, Date end);

    protected abstract void onMissedCall(Context ctx, String number, Date start);

    //Deals with actual events

    //Incoming call-  goes from IDLE to RINGING when it rings, to OFFHOOK when it's answered, to IDLE when its hung up
    //Outgoing call-  goes from IDLE to OFFHOOK when it dials out, to IDLE when hung up
    public void onCallStateChanged(Context context, int state, String number) {
        if(lastState == state){
            //No change, debounce extras
            return;
        }
        switch (state) {
            case TelephonyManager.CALL_STATE_RINGING:
                isIncoming = true;
                callStartTime = new Date();
                savedNumber = number;
                onIncomingCallReceived(context, number, callStartTime);
                break;
            case TelephonyManager.CALL_STATE_OFFHOOK:
                //Transition of ringing->offhook are pickups of incoming calls.  Nothing done on them
                if(lastState != TelephonyManager.CALL_STATE_RINGING){
                    isIncoming = false;
                    callStartTime = new Date();
                    onOutgoingCallStarted(context, savedNumber, callStartTime);                     
                }
                else
                {
                    isIncoming = true;
                    callStartTime = new Date();
                    onIncomingCallAnswered(context, savedNumber, callStartTime); 
                }

                break;
            case TelephonyManager.CALL_STATE_IDLE:
                //Went to idle-  this is the end of a call.  What type depends on previous state(s)
                if(lastState == TelephonyManager.CALL_STATE_RINGING){
                    //Ring but no pickup-  a miss
                    onMissedCall(context, savedNumber, callStartTime);
                }
                else if(isIncoming){
                    onIncomingCallEnded(context, savedNumber, callStartTime, new Date());                       
                }
                else{
                    onOutgoingCallEnded(context, savedNumber, callStartTime, new Date());                                               
                }
                break;
        }
        lastState = state;
    }
}

Then to use it, simply derive a class from it and implement a few easy functions, whichever call types you care about:

public class CallReceiver extends PhonecallReceiver {

    @Override
    protected void onIncomingCallReceived(Context ctx, String number, Date start)
    {
        //
    }

    @Override
    protected void onIncomingCallAnswered(Context ctx, String number, Date start)
    {
        //
    }

    @Override
    protected void onIncomingCallEnded(Context ctx, String number, Date start, Date end)
    {
        //
    }

    @Override
    protected void onOutgoingCallStarted(Context ctx, String number, Date start)
    {
        //
    } 

    @Override 
    protected void onOutgoingCallEnded(Context ctx, String number, Date start, Date end)
    {
        //
    }

    @Override
    protected void onMissedCall(Context ctx, String number, Date start)
    {
        //
    }

}

In addition you can see a writeup I did on why the code is like it is on my blog. Gist link: https://gist.github.com/ftvs/e61ccb039f511eb288ee

EDIT: Updated to simpler code, as I've reworked the class for my own use

Select an Option from the Right-Click Menu in Selenium Webdriver - Java

Using python webdriver right click operation

from selenium import webdriver

from selenium.webdriver import ActionChains

import time

driver = webdriver.Chrome()

driver.get("https://swisnl.github.io/jQuery-contextMenu/demo.html")
button=driver.find_element_by_xpath("//body[@class='wy-body-for-nav']")

action=ActionChains(driver)
action.context_click(button).perform()

Unable to find the requested .Net Framework Data Provider in Visual Studio 2010 Professional

I have seen reports of people having and additional, self terminating node in the machine.config file. Removing it resolved their issue. machine.config is found in \Windows\Microsoft.net\Framework\vXXXX\Config. You could have a multitude of config files based on how many versions of the framework are installed, including 32 and 64 bit variants.

<system.data>
    <DbProviderFactories>
        <add name="Odbc Data Provider" invariant="System.Data.Odbc" ... />
        <add name="OleDb Data Provider" invariant="System.Data.OleDb" ... />
        <add name="OracleClient Data Provider" invariant="System.Data ... />
        <add name="SqlClient Data Provider" invariant="System.Data ... />
        <add name="IBM DB2 for i .NET Provider" invariant="IBM.Data ... />
        <add name="Microsoft SQL Server Compact Data Provider" ... />     
    </DbProviderFactories>

    <DbProviderFactories/>  //remove this one!
</system.data>

Make a nav bar stick

I would recommend to use Bootstrap. http://getbootstrap.com/. This approach is very straight-forward and light weight.

<div class="navbar navbar-inverse navbar-fixed-top">
   <div class="container">
      <div class="navbar-collapse collapse">
         <ul class="nav navbar-nav navbar-fixed-top">
            <li><a href="#home"> <br>BLINK</a></li>
                <li><a href="#news"><br>ADVERTISING WITH BLINK</a></li>
                <li><a href="#contact"><br>EDUCATING WITH BLINK</a></li>
                <li><a href="#about"><br>ABOUT US</a></li>
            </ul>
        </div>
    </div>
</div>

You need to include the Bootstrap into your project, which will include the necessary scripts and styles. Then just call the class 'navbar-fixed-top'. This will do the trick. See above example

jQuery: click function exclude children.

Here is an example. Green square is parent and yellow square is child element.

Hope that this helps.

_x000D_
_x000D_
var childElementClicked;_x000D_
_x000D_
$("#parentElement").click(function(){_x000D_
_x000D_
  $("#childElement").click(function(){_x000D_
     childElementClicked = true;_x000D_
  });_x000D_
_x000D_
  if( childElementClicked != true ) {_x000D_
_x000D_
   // It is clicked on parent but not on child._x000D_
      // Now do some action that you want._x000D_
      alert('Clicked on parent');_x000D_
   _x000D_
  }else{_x000D_
      alert('Clicked on child');_x000D_
    }_x000D_
    _x000D_
    childElementClicked = false;_x000D_
 _x000D_
});
_x000D_
#parentElement{_x000D_
width:200px;_x000D_
height:200px;_x000D_
background-color:green;_x000D_
position:relative;_x000D_
}_x000D_
_x000D_
#childElement{_x000D_
margin-top:50px;_x000D_
margin-left:50px;_x000D_
width:100px;_x000D_
height:100px;_x000D_
background-color:yellow;_x000D_
position:absolute;_x000D_
}
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
<div id="parentElement">_x000D_
  <div id="childElement">_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Styling every 3rd item of a list using CSS?

You can use the :nth-child selector for that

li:nth-child(3n) {
 /* your rules here */
}

Flask - Calling python function on button OnClick event

It sounds like you want to use this web application as a remote control for your robot, and a core issue is that you won't want a page reload every time you perform an action, in which case, the last link you posted answers your problem.

I think you may be misunderstanding a few things about Flask. For one, you can't nest multiple functions in a single route. You're not making a set of functions available for a particular route, you're defining the one specific thing the server will do when that route is called.

With that in mind, you would be able to solve your problem with a page reload by changing your app.py to look more like this:

from flask import Flask, render_template, Response, request, redirect, url_for
app = Flask(__name__)

@app.route("/")
def index():
    return render_template('index.html')

@app.route("/forward/", methods=['POST'])
def move_forward():
    #Moving forward code
    forward_message = "Moving Forward..."
    return render_template('index.html', forward_message=forward_message);

Then in your html, use this:

<form action="/forward/" method="post">
    <button name="forwardBtn" type="submit">Forward</button>
</form>

...To execute your moving forward code. And include this:

{{ forward_message }} 

... where you want the moving forward message to appear on your template.

This will cause your page to reload, which is inevitable without using AJAX and Javascript.

Getting a map() to return a list in Python 3.x

Another option is to create a shortcut, returning a list:

from functools import reduce
_compose = lambda f, g: lambda *args: f(g(*args))
lmap = reduce(_compose, (list, map))

>>> lmap(chr, [66, 53, 0, 94])
['B', '5', '\x00', '^']

Oracle: SQL select date with timestamp

You can specify the whole day by doing a range, like so:

WHERE bk_date >= TO_DATE('2012-03-18', 'YYYY-MM-DD')
AND bk_date <  TO_DATE('2012-03-19', 'YYYY-MM-DD')

More simply you can use TRUNC:

WHERE TRUNC(bk_date) = TO_DATE('2012-03-18', 'YYYY-MM-DD')

TRUNC without parameter removes hours, minutes and seconds from a DATE.

Multiple Java versions running concurrently under Windows

It is absolutely possible to install side-by-side several JRE/JDK versions. Moreover, you don't have to do anything special for that to happen, as Sun is creating a different folder for each (under Program Files).

There is no control panel to check which JRE works for each application. Basically, the JRE that will work would be the first in your PATH environment variable. You can change that, or the JAVA_HOME variable, or create specific cmd/bat files to launch the applications you desire, each with a different JRE in path.

How to create Toast in Flutter?

Add flutter_just_toast to your dependencies in your Pubspecs.yaml

dependencies:

flutter_just_toast: ^1.0.1

Next import package into your class:

import 'package:flutter_just_toast/flutter_just_toast.dart';

Implement Toast with message

Toast.show( message: "Your toast message", 
    duration: Delay.SHORT, 
    textColor: Colors.black);

PHP fopen() Error: failed to open stream: Permission denied

You may need to change the permissions as an administrator. Open up terminal on your Mac and then open the directory that markers.xml is located in. Then type:

sudo chmod 777 markers.xml

You may be prompted for a password. Also, it could be the directories that don't allow full access. I'm not familiar with WordPress, so you may have to change the permission of each directory moving upward to the mysite directory.

How to retrieve images from MySQL database and display in an html tag

add $row = mysql_fetch_object($result); after your mysql_query();

your html <img src="<?php echo $row->dvdimage; ?>" width="175" height="200" />

Swing vs JavaFx for desktop applications

What will be cleaner and easier to maintain?

All things being equal, probably JavaFX - the API is much more consistent across components. However, this depends much more on how the code is written rather than what library is used to write it.

And what will be faster to build from scratch?

Highly dependent on what you're building. Swing has more components around for it (3rd party as well as built in) and not all of them have made their way to the newer JavaFX platform yet, so there may be a certain amount of re-inventing the wheel if you need something a bit custom. On the other hand, if you want to do transitions / animations / video stuff then this is orders of magnitude easier in FX.

One other thing to bear in mind is (perhaps) look and feel. If you absolutely must have the default system look and feel, then JavaFX (at present) can't provide this. Not a big must have for me (I prefer the default FX look anyway) but I'm aware some policies mandate a restriction to system styles.

Personally, I see JavaFX as the "up and coming" UI library that's not quite there yet (but more than usable), and Swing as the borderline-legacy UI library that's fully featured and supported for the moment, but probably won't be so much in the years to come (and therefore chances are FX will overtake it at some point.)

bash: Bad Substitution

I was adding a dollar sign twice in an expression with curly braces in bash:

cp -r $PROJECT_NAME ${$PROJECT_NAME}2

instead of

cp -r $PROJECT_NAME ${PROJECT_NAME}2

Display Adobe pdf inside a div

I don't think you can. You may need to use an Iframe instead.

HTML tag inside JavaScript

<div id="demo"></div>

<input type="submit" name="submit" id="submit" value="Submit" onClick="return empty()">


<script type="text/javascript">
        function empty()
        {
          var x;
          x = document.getElementById("feedbackpost").value;
          if (x == "")
           {
             var demo = document.getElementById("demo");
             demo.innerHTML =document.write='<h1>Hello member</h1>';
              return false;
           };
        }
    </script>

Checking for an empty field with MySQL

check this code for the problem:

$sql = "SELECT * FROM tablename WHERE condition";

$res = mysql_query($sql);

while ($row = mysql_fetch_assoc($res)) {

    foreach($row as $key => $field) {  

        echo "<br>";

        if(empty($row[$key])){

            echo $key." : empty field :"."<br>"; 

        }else{

        echo $key." =" . $field."<br>";     

        }
    }
}

Selenium and xPath - locating a link by containing text

@FindBy(xpath = "//button[@class='btn btn-primary' and contains(text(), 'Submit')]") private WebElementFacade submitButton;

public void clickOnSubmitButton() {
    submitButton.click();
}   

How to properly add include directories with CMake

First, you use include_directories() to tell CMake to add the directory as -I to the compilation command line. Second, you list the headers in your add_executable() or add_library() call.

As an example, if your project's sources are in src, and you need headers from include, you could do it like this:

include_directories(include)

add_executable(MyExec
  src/main.c
  src/other_source.c
  include/header1.h
  include/header2.h
)

jQuery's .click - pass parameters to user function

I get the simple solution:

 <button id="btn1" onclick="sendData(20)">ClickMe</button>

<script>
   var id; // global variable
   function sendData(valueId){
     id = valueId;
   }
   $("#btn1").click(function(){
        alert(id);
     });
</script>

My mean is that pass the value onclick event to the javascript function sendData(), initialize to the variable and take it by the jquery event handler method.

This is possible since at first sendData(valueid) gets called and initialize the value. Then after jquery event get's executed and use that value.

This is the straight forward solution and For Detail solution go Here.

SSL Error: unable to get local issuer certificate

If you are a linux user Update node to a later version by running

sudo apt update

 sudo apt install build-essential checkinstall libssl-dev

curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.35.1/install.sh | bash

nvm --version

nvm ls

nvm ls-remote

nvm install [version.number]

this should solve your problem

Javascript swap array elements

Here is a variation that first checks if the index exists in the array:

Array.prototype.swapItems = function(a, b){
    if(  !(a in this) || !(b in this) )
        return this;
    this[a] = this.splice(b, 1, this[a])[0];
    return this;
}

It currently will just return this if the index does not exist, but you could easily modify behavior on fail

changing default x range in histogram matplotlib

import matplotlib.pyplot as plt


...


plt.xlim(xmin=6.5, xmax = 12.5)

Is it possible to "decompile" a Windows .exe? Or at least view the Assembly?

If you are just trying to figure out what a malware does, it might be much easier to run it under something like the free tool Process Monitor which will report whenever it tries to access the filesystem, registry, ports, etc...

Also, using a virtual machine like the free VMWare server is very helpful for this kind of work. You can make a "clean" image, and then just go back to that every time you run the malware.

How do I convert a PDF document to a preview image in PHP?

Here is a simple class I've written and used on a couple of projects. It just wraps imagick and handles writing each page out to disk. If anyone is still looking for an easy way to do this, this link might be helpful.

Android, Java: HTTP POST Request

I used the following code to send HTTP POST from my android client app to C# desktop app on my server:

// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.yoursite.com/script.php");

try {
    // Add your data
    List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
    nameValuePairs.add(new BasicNameValuePair("id", "12345"));
    nameValuePairs.add(new BasicNameValuePair("stringdata", "AndDev is Cool!"));
    httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

    // Execute HTTP Post Request
    HttpResponse response = httpclient.execute(httppost);

} catch (ClientProtocolException e) {
    // TODO Auto-generated catch block
} catch (IOException e) {
    // TODO Auto-generated catch block
}

I worked on reading the request from a C# app on my server (something like a web server little application). I managed to read request posted data using the following code:

server = new HttpListener();
server.Prefixes.Add("http://*:50000/");
server.Start();

HttpListenerContext context = server.GetContext();
HttpListenerContext context = obj as HttpListenerContext;
HttpListenerRequest request = context.Request;

StreamReader sr = new StreamReader(request.InputStream);
string str = sr.ReadToEnd();

When do I need a fb:app_id or fb:admins?

To use the Like Button and have the Open Graph inspect your website, you need an application.

So you need to associate the Like Button with a fb:app_id

If you want other users to see the administration page for your website on Facebook you add fb:admins. So if you are the developer of the application and the website owner there is no need to add fb:admins

What is a StackOverflowError?

A StackOverflowError is a runtime error in java.

It is thrown when the amount of call stack memory allocated by JVM is exceeded.

A common case of a StackOverflowError being thrown, is when call stack exceeds due to excessive deep or infinite recursion.

Example:

public class Factorial {
    public static int factorial(int n){
        if(n == 1){
            return 1;
        }
        else{
            return n * factorial(n-1);
        }
    }

    public static void main(String[] args){
        System.out.println("Main method started");
        int result = Factorial.factorial(-1);
        System.out.println("Factorial ==>"+result);
        System.out.println("Main method ended");
    }
}

Stack trace:

Main method started
Exception in thread "main" java.lang.StackOverflowError
at com.program.stackoverflow.Factorial.factorial(Factorial.java:9)
at com.program.stackoverflow.Factorial.factorial(Factorial.java:9)
at com.program.stackoverflow.Factorial.factorial(Factorial.java:9)

In the above case, it can be avoided by doing programmatic changes. But if the program logic is correct and it still occurs then you stack size needs to be increased.

'Access-Control-Allow-Origin' issue when API call made from React (Isomorphic app)

I don't know if this will help but I was getting the same error when remote debugging a react-native application. I was running the debugger on 192.168.x.x:8081. I read a little bit on this Cross-Origin Resource Sharing (CORS) to educate myself on what CORS is. (I'm a beginner) and changed my URL from IP:8081 to localhost:8081 and my issue was resolved.

Determine which MySQL configuration file is being used

Using MySQL Workbench it will be shown under "Server Status": enter image description here

log4j logging hierarchy order

Hierarchy of log4j logging levels are as follows in Highest to Lowest order :

  • TRACE
  • DEBUG
  • INFO
  • WARN
  • ERROR
  • FATAL
  • OFF

TRACE log level provides highest logging which would be helpful to troubleshoot issues. DEBUG log level is also very useful to trouble shoot the issues.

You can also refer this link for more information about log levels : https://logging.apache.org/log4j/2.0/manual/architecture.html

How to create a TextArea in Android

<EditText
    android:id="@+id/comments_textbox"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="comments"
    android:inputType="textMultiLine"
    android:longClickable="false" />

use it to create multi line text box like textArea in Html

How to change status bar color in Flutter?

Works totally fine in my app

import 'package:flutter_statusbarcolor/flutter_statusbarcolor.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    FlutterStatusbarcolor.setStatusBarColor(Colors.white);
    return MaterialApp(
      title: app_title,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: HomePage(title: home_title),
    );
  }
}

(this package)

UPD: Another solution

SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle(
  statusBarColor: Colors.white
));

Printing integer variable and string on same line in SQL

declare @x INT = 1 /* Declares an integer variable named "x" with the value of 1 */
    
PRINT 'There are ' + CAST(@x AS VARCHAR) + ' alias combinations did not match a record' /* Prints a string concatenated with x casted as a varchar */

Parsing a JSON string in Ruby

I suggest Oj as it is waaaaaay faster than the standard JSON library.

https://github.com/ohler55/oj

(see performance comparisons here)

Scroll to a div using jquery

There is no .scrollTo() method in jQuery, but there is a .scrollTop() one. .scrollTop expects a parameter, that is, the pixel value where the scrollbar should scroll to.

Example:

$(window).scrollTop(200);

will scroll the window (if there is enough content in it).

So you can get this desired value with .offset() or .position().

Example:

$(window).scrollTop($('#contact').offset().top);

This should scroll the #contact element into view.

The non-jQuery alternate method is .scrollIntoView(). You can call that method on any DOM element like:

$('#contact')[0].scrollIntoView(true);

true indicates that the element is positioned at the top whereas false would place it on the bottom of the view. The nice thing with the jQuery method is, you can even use it with fx functions like .animate(). So you might smooth scroll something.

Reference: .scrollTop(), .position(), .offset()

Git: Create a branch from unstaged/uncommitted changes on master

Try:

git stash
git checkout -b new-branch
git stash apply

show all tags in git log

git log --no-walk --tags --pretty="%h %d %s" --decorate=full

This version will print the commit message as well:

 $ git log --no-walk --tags --pretty="%h %d %s" --decorate=full
3713f3f  (tag: refs/tags/1.0.0, tag: refs/tags/0.6.0, refs/remotes/origin/master, refs/heads/master) SP-144/ISP-177: Updating the package.json with 0.6.0 version and the README.md.
00a3762  (tag: refs/tags/0.5.0) ISP-144/ISP-205: Update logger to save files with optional port number if defined/passed: Version 0.5.0
d8db998  (tag: refs/tags/0.4.2) ISP-141/ISP-184/ISP-187: Fixing the bug when loading the app with Gulp and Grunt for 0.4.2
3652484  (tag: refs/tags/0.4.1) ISP-141/ISP-184: Missing the package.json and README.md updates with the 0.4.1 version
c55eee7  (tag: refs/tags/0.4.0) ISP-141/ISP-184/ISP-187: Updating the README.md file with the latest 1.3.0 version.
6963d0b  (tag: refs/tags/0.3.0) ISP-141/ISP-184: Add support for custom serializers: README update
4afdbbe  (tag: refs/tags/0.2.0) ISP-141/ISP-143/ISP-144: Fixing a bug with the creation of the logs
e1513f1  (tag: refs/tags/0.1.0) ISP-141/ISP-143: Betterr refactoring of the Loggers, no dependencies, self-configuration for missing settings.

How to use http.client in Node.js if there is basic authorization

You have to set the Authorization field in the header.

It contains the authentication type Basic in this case and the username:password combination which gets encoded in Base64:

var username = 'Test';
var password = '123';
var auth = 'Basic ' + Buffer.from(username + ':' + password).toString('base64');
// new Buffer() is deprecated from v6

// auth is: 'Basic VGVzdDoxMjM='

var header = {'Host': 'www.example.com', 'Authorization': auth};
var request = client.request('GET', '/', header);

sudo service mongodb restart gives "unrecognized service error" in ubuntu 14.0.4

This is a simple solution that worked for me with the same problem (I think): mv /var/lib/mongodb /var/lib/mongodb_backup mkdir /var/lib/mongodb chmod 700 /var/lib/mongodb chown mongodb:daemon /var/lib/mongodb systemctl restart mongodb or service mongod restart

org.json.simple cannot be resolved

The jar file is missing. You can download the jar file and add it as external libraries in your project . You can download this from

http://www.findjar.com/jar/com/googlecode/json-simple/json-simple/1.1/json-simple-1.1.jar.html

Android EditText delete(backspace) key event

This seems to be working for me :

public void onTextChanged(CharSequence s, int start, int before, int count) {
    if (before - count == 1) {
        onBackSpace();
    } else if (s.subSequence(start, start + count).toString().equals("\n")) {
        onNewLine();
    }
}

Disable double-tap "zoom" option in browser on touch devices

I just wanted to answer my question properly as some people do not read the comments below an answer. So here it is:

(function($) {
  $.fn.nodoubletapzoom = function() {
      $(this).bind('touchstart', function preventZoom(e) {
        var t2 = e.timeStamp
          , t1 = $(this).data('lastTouch') || t2
          , dt = t2 - t1
          , fingers = e.originalEvent.touches.length;
        $(this).data('lastTouch', t2);
        if (!dt || dt > 500 || fingers > 1) return; // not double-tap

        e.preventDefault(); // double tap - prevent the zoom
        // also synthesize click events we just swallowed up
        $(this).trigger('click').trigger('click');
      });
  };
})(jQuery);

I did not write this, i just modified it. I found the iOS-only version here: https://gist.github.com/2047491 (thanks Kablam)

How to split a string with any whitespace chars as delimiters

All you need is to split using the one of the special character of Java Ragex Engine,

and that is- WhiteSpace Character

  • \d Represents a digit: [0-9]
  • \D Represents a non-digit: [^0-9]
  • \s Represents a whitespace character including [ \t\n\x0B\f\r]
  • \S Represents a non-whitespace character as [^\s]
  • \v Represents a vertical whitespace character as [\n\x0B\f\r\x85\u2028\u2029]
  • \V Represents a non-vertical whitespace character as [^\v]
  • \w Represents a word character as [a-zA-Z_0-9]
  • \W Represents a non-word character as [^\w]

Here, the key point to remember is that the small leter character \s represents all types of white spaces including a single space [ ] , tab characters [ ] or anything similar.

So, if you'll try will something like this-

String theString = "Java<a space><a tab>Programming"
String []allParts = theString.split("\\s+");

You will get the desired output.


Some Very Useful Links:


Hope, this might help you the best!!!

How can I use the HTML5 canvas element in IE?

The page is using excanvas - a JS library that simulates the canvas element using IE's VML renderer.

Note that in Internet Explorer 9, the canvas tag is supported natively! See MSDN docs for details...

How to use org.apache.commons package?

Download commons-net binary from here. Extract the files and reference the commons-net-x.x.jar file.

NSURLConnection Using iOS Swift

Swift 3.0

AsynchonousRequest

let urlString = "http://heyhttp.org/me.json"
var request = URLRequest(url: URL(string: urlString)!)
let session = URLSession.shared

session.dataTask(with: request) {data, response, error in
  if error != nil {
    print(error!.localizedDescription)
    return
  }

  do {
    let jsonResult: NSDictionary? = try JSONSerialization.jsonObject(with: data!, options: JSONSerialization.ReadingOptions.mutableContainers) as? NSDictionary
    print("Synchronous\(jsonResult)")
  } catch {
    print(error.localizedDescription)
  }
}.resume()

Is it possible to set an object to null?

"an object" of what type?

You can certainly assign NULL (and nullptr) to objects of pointer types, and it is implementation defined if you can assign NULL to objects of arithmetic types.

If you mean objects of some class type, the answer is NO (excepting classes that have operator= accepting pointer or arithmetic types)

"empty" is more plausible, as many types have both copy assignment and default construction (often implicitly). To see if an existing object is like a default constructed one, you will also need an appropriate bool operator==

How do you modify the web.config appSettings at runtime?

You need to use WebConfigurationManager.OpenWebConfiguration(): For Example:

Dim myConfiguration As Configuration = System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~")
myConfiguration.ConnectionStrings.ConnectionStrings("myDatabaseName").ConnectionString = txtConnectionString.Text
myConfiguration.AppSettings.Settings.Item("myKey").Value = txtmyKey.Text
myConfiguration.Save()

I think you might also need to set AllowLocation in machine.config. This is a boolean value that indicates whether individual pages can be configured using the element. If the "allowLocation" is false, it cannot be configured in individual elements.

Finally, it makes a difference if you run your application in IIS and run your test sample from Visual Studio. The ASP.NET process identity is the IIS account, ASPNET or NETWORK SERVICES (depending on IIS version).

Might need to grant ASPNET or NETWORK SERVICES Modify access on the folder where web.config resides.

Bootstrap 3, 4 and 5 .container-fluid with grid adding unwanted padding

I have used <div class="container-fluid" style="padding: 0px !important"> and it seems to be working.

creating a table in ionic

This is the way i use it. It's very simple and work very well.. Ionic html:

  <ion-content>
 

  <ion-grid class="ion-text-center">

    <ion-row class="ion-margin">
      <ion-col>
        <ion-title>
          <ion-text color="default">
            Your title remove if don't want use
          </ion-text>
        </ion-title>
      </ion-col>
    </ion-row>

    <ion-row class="header-row">
      <ion-col>
        <ion-text>Data</ion-text>
      </ion-col>

      <ion-col>
        <ion-text>Cliente</ion-text>
      </ion-col>

      <ion-col>
        <ion-text>Pagamento</ion-text>
      </ion-col>
    </ion-row>


    <ion-row>
      <ion-col>
        <ion-text>
            19/10/2020
        </ion-text>
      </ion-col>

        <ion-col>
          <ion-text>
            Nome
          </ion-text>
        </ion-col>
  
        <ion-col>
          <ion-text>
            R$ 200
          </ion-text>
        </ion-col>
    </ion-row>

  </ion-grid>
</ion-content>

CSS:

.header-row {
  background: #7163AA;
  color: #fff;
  font-size: 18px;
}

ion-col {
  border: 1px solid #ECEEEF;
}

Result of the code

How to delete all files from a specific folder?

string[] filePaths = Directory.GetFiles(@"c:\MyDir\");
foreach (string filePath in filePaths)
File.Delete(filePath);

Or in a single line:

Array.ForEach(Directory.GetFiles(@"c:\MyDir\"), File.Delete);

How to make function decorators and chain them together?

Paolo Bergantino's answer has the great advantage of only using the stdlib, and works for this simple example where there are no decorator arguments nor decorated function arguments.

However it has 3 major limitations if you want to tackle more general cases:

  • as already noted in several answers, you can not easily modify the code to add optional decorator arguments. For example creating a makestyle(style='bold') decorator is non-trivial.
  • besides, wrappers created with @functools.wraps do not preserve the signature, so if bad arguments are provided they will start executing, and might raise a different kind of error than the usual TypeError.
  • finally, it is quite difficult in wrappers created with @functools.wraps to access an argument based on its name. Indeed the argument can appear in *args, in **kwargs, or may not appear at all (if it is optional).

I wrote decopatch to solve the first issue, and wrote makefun.wraps to solve the other two. Note that makefun leverages the same trick than the famous decorator lib.

This is how you would create a decorator with arguments, returning truly signature-preserving wrappers:

from decopatch import function_decorator, DECORATED
from makefun import wraps

@function_decorator
def makestyle(st='b', fn=DECORATED):
    open_tag = "<%s>" % st
    close_tag = "</%s>" % st

    @wraps(fn)
    def wrapped(*args, **kwargs):
        return open_tag + fn(*args, **kwargs) + close_tag

    return wrapped

decopatch provides you with two other development styles that hide or show the various python concepts, depending on your preferences. The most compact style is the following:

from decopatch import function_decorator, WRAPPED, F_ARGS, F_KWARGS

@function_decorator
def makestyle(st='b', fn=WRAPPED, f_args=F_ARGS, f_kwargs=F_KWARGS):
    open_tag = "<%s>" % st
    close_tag = "</%s>" % st
    return open_tag + fn(*f_args, **f_kwargs) + close_tag

In both cases you can check that the decorator works as expected:

@makestyle
@makestyle('i')
def hello(who):
    return "hello %s" % who

assert hello('world') == '<b><i>hello world</i></b>'    

Please refer to the documentation for details.

Microsoft Advertising SDK doesn't deliverer ads

I only use MicrosoftAdvertising.Mobile and Microsoft.Advertising.Mobile.UI and I am served ads. The SDK should only add the DLLs not reference itself.

Note: You need to explicitly set width and height Make sure the phone dialer, and web browser capabilities are enabled

Followup note: Make sure that after you've removed the SDK DLL, that the xmlns references are not still pointing to it. The best route to take here is

  1. Remove the XAML for the ad
  2. Remove the xmlns declaration (usually at the top of the page, but sometimes will be declared in the ad itself)
  3. Remove the bad DLL (the one ending in .SDK )
  4. Do a Clean and then Build (clean out anything remaining from the DLL)
  5. Add the xmlns reference (actual reference is below)
  6. Add the ad to the page (example below)

Here is the xmlns reference:

xmlns:AdNamepace="clr-namespace:Microsoft.Advertising.Mobile.UI;assembly=Microsoft.Advertising.Mobile.UI" 

Then the ad itself:

<AdNamespace:AdControl x:Name="myAd" Height="80" Width="480"                    AdUnitId="yourAdUnitIdHere" ApplicationId="yourIdHere"/> 

Maven and adding JARs to system scope

Try this configuration. It worked for me:

<plugin>
    <artifactId>maven-war-plugin</artifactId>
    <version>2.4</version>
    <configuration>
        <warSourceDirectory>mywebRoot</warSourceDirectory>
        <warSourceExcludes>source\**,build\**,dist\**,WEB-INF\lib\*,
            WEB-INF\classes\**,build.*
        </warSourceExcludes>
        <webXml>myproject/source/deploiement/web.xml</webXml>
        <webResources>
            <resource>
                <directory>mywebRoot/WEB-INF/lib</directory>
                <targetPath>WEB-INF/lib</targetPath>
                <includes>
                        <include>mySystemJar1.jar.jar</include>
                         <include>mySystemJar2.jar</include>
                   </includes>
            </resource>
        </webResources>
    </configuration>
</plugin>

How do I convert a number to a letter in Java?

Personally, I prefer

return "ABCDEFGHIJKLMNOPQRSTUVWXYZ".substring(i, i+1);

which shares the backing char[]. Alternately, I think the next-most-readable approach is

return Character.toString((char) (i + 'A'));

which doesn't depend on remembering ASCII tables. It doesn't do validation, but if you want to, I'd prefer to write

char c = (char) (i + 'A');
return Character.isUpperCase(c) ? Character.toString(c) : null;

just to make it obvious that you're checking that it's an alphabetic character.

How to query a MS-Access Table from MS-Excel (2010) using VBA

All you need is a ADODB.Connection

Dim cnn As ADODB.Connection ' Requieres reference to the
Dim rs As ADODB.Recordset   ' Microsoft ActiveX Data Objects Library

Set cnn = CreateObject("adodb.Connection")
cnn.Open "DRIVER={Microsoft Access Driver (*.mdb, *.accdb)};DBQ=C:\Access\webforums\whiteboard2003.mdb;"

Set rs = cnn.Execute(SQLQuery) ' Retrieve the data

How to initialize a struct in accordance with C programming language standards

a = (MYTYPE){ true, 15, 0.123 };

would do fine in C99

IOCTL Linux device driver

The ioctl function is useful for implementing a device driver to set the configuration on the device. e.g. a printer that has configuration options to check and set the font family, font size etc. ioctl could be used to get the current font as well as set the font to a new one. A user application uses ioctl to send a code to a printer telling it to return the current font or to set the font to a new one.

int ioctl(int fd, int request, ...)
  1. fd is file descriptor, the one returned by open;
  2. request is request code. e.g GETFONT will get the current font from the printer, SETFONT will set the font on the printer;
  3. the third argument is void *. Depending on the second argument, the third may or may not be present, e.g. if the second argument is SETFONT, the third argument can be the font name such as "Arial";

int request is not just a macro. A user application is required to generate a request code and the device driver module to determine which configuration on device must be played with. The application sends the request code using ioctl and then uses the request code in the device driver module to determine which action to perform.

A request code has 4 main parts

    1. A Magic number - 8 bits
    2. A sequence number - 8 bits
    3. Argument type (typically 14 bits), if any.
    4. Direction of data transfer (2 bits).  

If the request code is SETFONT to set font on a printer, the direction for data transfer will be from user application to device driver module (The user application sends the font name "Arial" to the printer). If the request code is GETFONT, direction is from printer to the user application.

In order to generate a request code, Linux provides some predefined function-like macros.

1._IO(MAGIC, SEQ_NO) both are 8 bits, 0 to 255, e.g. let us say we want to pause printer. This does not require a data transfer. So we would generate the request code as below

#define PRIN_MAGIC 'P'
#define NUM 0
#define PAUSE_PRIN __IO(PRIN_MAGIC, NUM) 

and now use ioctl as

ret_val = ioctl(fd, PAUSE_PRIN);

The corresponding system call in the driver module will receive the code and pause the printer.

  1. __IOW(MAGIC, SEQ_NO, TYPE) MAGIC and SEQ_NO are the same as above, and TYPE gives the type of the next argument, recall the third argument of ioctl is void *. W in __IOW indicates that the data flow is from user application to driver module. As an example, suppose we want to set the printer font to "Arial".
#define PRIN_MAGIC 'S'
#define SEQ_NO 1
#define SETFONT __IOW(PRIN_MAGIC, SEQ_NO, unsigned long)

further,

char *font = "Arial";
ret_val = ioctl(fd, SETFONT, font); 

Now font is a pointer, which means it is an address best represented as unsigned long, hence the third part of _IOW mentions type as such. Also, this address of font is passed to corresponding system call implemented in device driver module as unsigned long and we need to cast it to proper type before using it. Kernel space can access user space and hence this works. other two function-like macros are __IOR(MAGIC, SEQ_NO, TYPE) and __IORW(MAGIC, SEQ_NO, TYPE) where the data flow will be from kernel space to user space and both ways respectively.

Please let me know if this helps!

Raise warning in Python without interrupting program

You shouldn't raise the warning, you should be using warnings module. By raising it you're generating error, rather than warning.

Expression must be a modifiable L-value

lvalue means "left value" -- it should be assignable. You cannot change the value of text since it is an array, not a pointer.

Either declare it as char pointer (in this case it's better to declare it as const char*):

const char *text;
if(number == 2) 
    text = "awesome"; 
else 
    text = "you fail";

Or use strcpy:

char text[60];
if(number == 2) 
    strcpy(text, "awesome"); 
else 
    strcpy(text, "you fail");

python: how to get information about a function?

Try

help(my_list)

to get built-in help messages.

How to use ArrayList.addAll()?

Collections.addAll is what you want.

Collections.addAll(myArrayList, '+', '-', '*', '^');

Another option is to pass the list into the constructor using Arrays.asList like this:

List<Character> myArrayList = new ArrayList<Character>(Arrays.asList('+', '-', '*', '^'));

If, however, you are good with the arrayList being fixed-length, you can go with the creation as simple as list = Arrays.asList(...). Arrays.asList specification states that it returns a fixed-length list which acts as a bridge to the passed array, which could be not what you need.

cast_sender.js error: Failed to load resource: net::ERR_FAILED in Chrome

To stop seeing those cast_sender.js errors, edit the youtube link in the iframe src and change embed to v

[Vue warn]: Cannot find element

I think sometimes stupid mistakes can give us this error.

<div id="#main"> <--- id with hashtag
    <div id="mainActivity" v-component="{{currentActivity}}" class="activity"></div>
</div>

To

<div id="main"> <--- id without hashtag
    <div id="mainActivity" v-component="{{currentActivity}}" class="activity"></div>
</div>

Python main call within class

Well, first, you need to actually define a function before you can run it (and it doesn't need to be called main). For instance:

class Example(object):
    def run(self):
        print "Hello, world!"

if __name__ == '__main__':
    Example().run()

You don't need to use a class, though - if all you want to do is run some code, just put it inside a function and call the function, or just put it in the if block:

def main():
    print "Hello, world!"

if __name__ == '__main__':
    main()

or

if __name__ == '__main__':
    print "Hello, world!"

Is there an upper bound to BigInteger?

The number is held in an int[] - the maximum size of an array is Integer.MAX_VALUE. So the maximum BigInteger probably is (2 ^ 32) ^ Integer.MAX_VALUE.

Admittedly, this is implementation dependent, not part of the specification.


In Java 8, some information was added to the BigInteger javadoc, giving a minimum supported range and the actual limit of the current implementation:

BigInteger must support values in the range -2Integer.MAX_VALUE (exclusive) to +2Integer.MAX_VALUE (exclusive) and may support values outside of that range.

Implementation note: BigInteger constructors and operations throw ArithmeticException when the result is out of the supported range of -2Integer.MAX_VALUE (exclusive) to +2Integer.MAX_VALUE (exclusive).

Clicking a button within a form causes page refresh

Add action to your form.

<form action="#">

Best way to resolve file path too long exception

The best answer I can find, is in one of the comments here. Adding it to the answer so that someone won't miss the comment and should definitely try this out. It fixed the issue for me.

We need to map the solution folder to a drive using the "subst" command in command prompt- e.g., subst z:

And then open the solution from this drive (z in this case). This would shorten the path as much as possible and could solve the lengthy filename issue.

How can I check for Python version in a program that uses new language features?

import sys    
# prints whether python is version 3 or not
python_version = sys.version_info.major
if python_version == 3:
    print("is python 3")
else:
    print("not python 3")

Media Queries: How to target desktop, tablet, and mobile?

Since there are many varying screen sizes that always change and most likely will always change the best way to go is to base your break points and media queries on your design.

The easiest way to go about this is to grab your completed desktop design and open it in your web browser. Shrink the screen slowly to make it narrower. Observe to see when the design starts to, "break", or looks horrible and cramped. At this point a break point with a media query would be required.

It's common to create three sets of media queries for desktop, tablet and phone. But if your design looks good on all three, why bother with the complexity of adding three different media queries that are not necessary. Do it on an as-needed basis!

How to redirect to a 404 in Rails?

HTTP 404 Status

To return a 404 header, just use the :status option for the render method.

def action
  # here the code

  render :status => 404
end

If you want to render the standard 404 page you can extract the feature in a method.

def render_404
  respond_to do |format|
    format.html { render :file => "#{Rails.root}/public/404", :layout => false, :status => :not_found }
    format.xml  { head :not_found }
    format.any  { head :not_found }
  end
end

and call it in your action

def action
  # here the code

  render_404
end

If you want the action to render the error page and stop, simply use a return statement.

def action
  render_404 and return if params[:something].blank?

  # here the code that will never be executed
end

ActiveRecord and HTTP 404

Also remember that Rails rescues some ActiveRecord errors, such as the ActiveRecord::RecordNotFound displaying the 404 error page.

It means you don't need to rescue this action yourself

def show
  user = User.find(params[:id])
end

User.find raises an ActiveRecord::RecordNotFound when the user doesn't exist. This is a very powerful feature. Look at the following code

def show
  user = User.find_by_email(params[:email]) or raise("not found")
  # ...
end

You can simplify it by delegating to Rails the check. Simply use the bang version.

def show
  user = User.find_by_email!(params[:email])
  # ...
end

SQL Server : fetching records between two dates?

As others have answered, you probably have a DATETIME (or other variation) column and not a DATE datatype.

Here's a condition that works for all, including DATE:

SELECT * 
FROM xxx 
WHERE dates >= '20121026' 
  AND dates <  '20121028'    --- one day after 
                             --- it is converted to '2012-10-28 00:00:00.000'
 ;

@Aaron Bertrand has blogged about this at: What do BETWEEN and the devil have in common?

Best way to find the intersection of multiple sets?

As of 2.6, set.intersection takes arbitrarily many iterables.

>>> s1 = set([1, 2, 3])
>>> s2 = set([2, 3, 4])
>>> s3 = set([2, 4, 6])
>>> s1 & s2 & s3
set([2])
>>> s1.intersection(s2, s3)
set([2])
>>> sets = [s1, s2, s3]
>>> set.intersection(*sets)
set([2])

Class JavaLaunchHelper is implemented in two places

I am using Intellij Idea 2017 and I got into the same problem. What solved the problem for me was to simply

  1. close the project in intelliJ
  2. File -> New -> project from existing resources
  3. use Import from external model (if any)
  4. open the project again.

How to plot ROC curve in Python

I have made a simple function included in a package for the ROC curve. I just started practicing machine learning so please also let me know if this code has any problem!

Have a look at the github readme file for more details! :)

https://github.com/bc123456/ROC

from sklearn.metrics import confusion_matrix, accuracy_score, roc_auc_score, roc_curve
import matplotlib.pyplot as plt
import seaborn as sns
import numpy as np

def plot_ROC(y_train_true, y_train_prob, y_test_true, y_test_prob):
    '''
    a funciton to plot the ROC curve for train labels and test labels.
    Use the best threshold found in train set to classify items in test set.
    '''
    fpr_train, tpr_train, thresholds_train = roc_curve(y_train_true, y_train_prob, pos_label =True)
    sum_sensitivity_specificity_train = tpr_train + (1-fpr_train)
    best_threshold_id_train = np.argmax(sum_sensitivity_specificity_train)
    best_threshold = thresholds_train[best_threshold_id_train]
    best_fpr_train = fpr_train[best_threshold_id_train]
    best_tpr_train = tpr_train[best_threshold_id_train]
    y_train = y_train_prob > best_threshold

    cm_train = confusion_matrix(y_train_true, y_train)
    acc_train = accuracy_score(y_train_true, y_train)
    auc_train = roc_auc_score(y_train_true, y_train)

    print 'Train Accuracy: %s ' %acc_train
    print 'Train AUC: %s ' %auc_train
    print 'Train Confusion Matrix:'
    print cm_train

    fig = plt.figure(figsize=(10,5))
    ax = fig.add_subplot(121)
    curve1 = ax.plot(fpr_train, tpr_train)
    curve2 = ax.plot([0, 1], [0, 1], color='navy', linestyle='--')
    dot = ax.plot(best_fpr_train, best_tpr_train, marker='o', color='black')
    ax.text(best_fpr_train, best_tpr_train, s = '(%.3f,%.3f)' %(best_fpr_train, best_tpr_train))
    plt.xlim([0.0, 1.0])
    plt.ylim([0.0, 1.0])
    plt.xlabel('False Positive Rate')
    plt.ylabel('True Positive Rate')
    plt.title('ROC curve (Train), AUC = %.4f'%auc_train)

    fpr_test, tpr_test, thresholds_test = roc_curve(y_test_true, y_test_prob, pos_label =True)

    y_test = y_test_prob > best_threshold

    cm_test = confusion_matrix(y_test_true, y_test)
    acc_test = accuracy_score(y_test_true, y_test)
    auc_test = roc_auc_score(y_test_true, y_test)

    print 'Test Accuracy: %s ' %acc_test
    print 'Test AUC: %s ' %auc_test
    print 'Test Confusion Matrix:'
    print cm_test

    tpr_score = float(cm_test[1][1])/(cm_test[1][1] + cm_test[1][0])
    fpr_score = float(cm_test[0][1])/(cm_test[0][0]+ cm_test[0][1])

    ax2 = fig.add_subplot(122)
    curve1 = ax2.plot(fpr_test, tpr_test)
    curve2 = ax2.plot([0, 1], [0, 1], color='navy', linestyle='--')
    dot = ax2.plot(fpr_score, tpr_score, marker='o', color='black')
    ax2.text(fpr_score, tpr_score, s = '(%.3f,%.3f)' %(fpr_score, tpr_score))
    plt.xlim([0.0, 1.0])
    plt.ylim([0.0, 1.0])
    plt.xlabel('False Positive Rate')
    plt.ylabel('True Positive Rate')
    plt.title('ROC curve (Test), AUC = %.4f'%auc_test)
    plt.savefig('ROC', dpi = 500)
    plt.show()

    return best_threshold

A sample roc graph produced by this code

Error 6 (net::ERR_FILE_NOT_FOUND): The files c or directory could not be found

If this is an HTML file where you are using file://FileName then using a CDN like src="//cdnjs.cloudflare.com/ajax/libs/angular.js/1.2.1/angular.min.js" will not work.

You will have to include the .js file in your code.

What is the difference between java and core java?

Core Java is Sun Microsystem's, used to refer to Java SE. And there are Java ME and Java EE (J2EE). So this is told in order to differentiate with the Java ME and J2EE. So I feel Core Java is only used to mention J2SE.

Java having 3 category:

J2SE(Java to Standard Edition) - Core Java

J2EE(Java to Enterprises Edition)- Advance Java + Framework

J2ME(Java to Micro Edition)

Thank You..

getting the table row values with jquery

Give something like this a try:

$(document).ready(function(){
    $("#thisTable tr").click(function(){
        $(this).find("td").each(function(){
            alert($(this).html());
        });
    });
});?

Here is a fiddle of the code in action: http://jsfiddle.net/YhZsW/

How to remove jar file from local maven repository which was added with install:install-file?

Although deleting files manually works, there is an official way of removing dependencies of your project from your local (cache) repository and optionally re-resolving them from remote repositories.

The goal purge-local-repository, on the standard Maven dependency plugin, will remove the locally installed dependencies of this project from your cache. Optionally, you may re-resolve them from the remote repositories at the same time.

This should be used as part of a project phase because it applies to the dependencies for the containing project. Also transitive dependencies will be purged (locally) as well, by default.

If you want to explicitly remove a single artifact from the cache, use purge-local-repository with the manualInclude parameter. For example, from the command line:

mvn dependency:purge-local-repository -DmanualInclude="groupId:artifactId, ..."

The documentation implies that this does not remove transitive dependencies by default. If you are running with a non-standard cache location, or on multiple platforms, these are more reliable than deleting files "by hand".

The full documentation is in the maven-dependency-plugin spec.

Note: Older versions of the maven dependency plugin had a manual-purge-local-repository goal, which is now (version 2.8) implied by the use of manualInclude. The documentation for manualIncludes (with an s) should be read as well.

How to register multiple servlets in web.xml in one Spring application

Use config something like this:

<context-param>
  <param-name>contextConfigLocation</param-name>
  <param-value>/WEB-INF/applicationContext.xml</param-value>
</context-param>

<listener>
  <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<servlet>
  <servlet-name>myservlet</servlet-name>
  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  <load-on-startup>1</load-on-startup>
</servlet>

<servlet>
  <servlet-name>user-webservice</servlet-name>
  <servlet-class>org.apache.cxf.transport.servlet.CXFServlet</servlet-class>
  <load-on-startup>2</load-on-startup>
</servlet>

and then you'll need three files:

  • applicationContext.xml;
  • myservlet-servlet.xml; and
  • user-webservice-servlet.xml.

The *-servlet.xml files are used automatically and each creates an application context for that servlet.

From the Spring documentation, 13.2. The DispatcherServlet:

The framework will, on initialization of a DispatcherServlet, look for a file named [servlet-name]-servlet.xml in the WEB-INF directory of your web application and create the beans defined there (overriding the definitions of any beans defined with the same name in the global scope).

How do I delete an entity from symfony2

Symfony is smart and knows how to make the find() by itself :

public function deleteGuestAction(Guest $guest)
{
    if (!$guest) {
        throw $this->createNotFoundException('No guest found');
    }

    $em = $this->getDoctrine()->getEntityManager();
    $em->remove($guest);
    $em->flush();

    return $this->redirect($this->generateUrl('GuestBundle:Page:viewGuests.html.twig'));
}

To send the id in your controller, use {{ path('your_route', {'id': guest.id}) }}

Extract specific columns from delimited file using Awk

Other languages have short cuts for ranges of field numbers, but not awk, you'll have to write your code as your fear ;-)

awk -F, 'BEGIN {OFS=","} { print $1, $2, $3, $4 ..... $30, $33}' infile.csv > outfile.csv

There is no direct function in awk to use field names as column specifiers.

I hope this helps.

Erase the current printed console line

You can use VT100 escape codes. Most terminals, including xterm, are VT100 aware. For erasing a line, this is ^[[2K. In C this gives:

printf("%c[2K", 27);

How to convert const char* to char* in C?

You can use the strdup function which has the following prototype

char *strdup(const char *s1);

Example of use:

#include <string.h>

char * my_str = strdup("My string literal!");
char * my_other_str = strdup(some_const_str);

or strcpy/strncpy to your buffer

or rewrite your functions to use const char * as parameter instead of char * where possible so you can preserve the const

How to Automatically Start a Download in PHP?

Send the following headers before outputting the file:

header("Content-Disposition: attachment; filename=\"" . basename($File) . "\"");
header("Content-Type: application/octet-stream");
header("Content-Length: " . filesize($File));
header("Connection: close");

@grom: Interesting about the 'application/octet-stream' MIME type. I wasn't aware of that, have always just used 'application/force-download' :)

How do I tell if a regular file does not exist in Bash?

I prefer to do the following one-liner, in POSIX shell compatible format:

$ [ -f "/$DIR/$FILE" ] || echo "$FILE NOT FOUND"

$ [ -f "/$DIR/$FILE" ] && echo "$FILE FOUND"

For a couple of commands, like I would do in a script:

$  [ -f "/$DIR/$FILE" ] || { echo "$FILE NOT FOUND" ; exit 1 ;}

Once I started doing this, I rarely use the fully typed syntax anymore!!

What is Hive: Return Code 2 from org.apache.hadoop.hive.ql.exec.MapRedTask

I was also facing same error when I was inserting the data into HIVE external table which was pointing to Elastic search cluster.

I replaced the older JAR elasticsearch-hadoop-2.0.0.RC1.jar to elasticsearch-hadoop-5.6.0.jar, and everything worked fine.

My Suggestion is please use the specific JAR as per the elastic search version. Don't use older JARs if you are using newer version of elastic search.

Thanks to this post Hive- Elasticsearch Write Operation #409

Adding a Method to an Existing Object Instance

In Python, there is a difference between functions and bound methods.

>>> def foo():
...     print "foo"
...
>>> class A:
...     def bar( self ):
...         print "bar"
...
>>> a = A()
>>> foo
<function foo at 0x00A98D70>
>>> a.bar
<bound method A.bar of <__main__.A instance at 0x00A9BC88>>
>>>

Bound methods have been "bound" (how descriptive) to an instance, and that instance will be passed as the first argument whenever the method is called.

Callables that are attributes of a class (as opposed to an instance) are still unbound, though, so you can modify the class definition whenever you want:

>>> def fooFighters( self ):
...     print "fooFighters"
...
>>> A.fooFighters = fooFighters
>>> a2 = A()
>>> a2.fooFighters
<bound method A.fooFighters of <__main__.A instance at 0x00A9BEB8>>
>>> a2.fooFighters()
fooFighters

Previously defined instances are updated as well (as long as they haven't overridden the attribute themselves):

>>> a.fooFighters()
fooFighters

The problem comes when you want to attach a method to a single instance:

>>> def barFighters( self ):
...     print "barFighters"
...
>>> a.barFighters = barFighters
>>> a.barFighters()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: barFighters() takes exactly 1 argument (0 given)

The function is not automatically bound when it's attached directly to an instance:

>>> a.barFighters
<function barFighters at 0x00A98EF0>

To bind it, we can use the MethodType function in the types module:

>>> import types
>>> a.barFighters = types.MethodType( barFighters, a )
>>> a.barFighters
<bound method ?.barFighters of <__main__.A instance at 0x00A9BC88>>
>>> a.barFighters()
barFighters

This time other instances of the class have not been affected:

>>> a2.barFighters()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: A instance has no attribute 'barFighters'

More information can be found by reading about descriptors and metaclass programming.

No line-break after a hyphen

Late to the party, but I think this is actually the most elegant. Use the WORD JOINER Unicode character &#8288; on either side of your hyphen, or em dash, or any character.

So, like so:

&#8288;—&#8288;

This will join the symbol on both ends to its neighbors (without adding a space) and prevent line breaking.

Convert object string to JSON

You have to write round brackets, because without them eval will consider code inside curly brackets as block of commands.

var i = eval("({ hello: 'world', places: ['Africa', 'America', 'Asia', 'Australia'] })");

LINQ to Entities how to update a record

//for update

(from x in dataBase.Customers
         where x.Name == "Test"
         select x).ToList().ForEach(xx => xx.Name="New Name");

//for delete

dataBase.Customers.RemoveAll(x=>x.Name=="Name");

Center an element with "absolute" position and undefined width in CSS?

Try not to use the dark side of the CSS. Avoid using negative values for margins. I know that sometimes you are forced to do awful things like a margin-left: -450px, but probably you could do something like right: 450px. It's just my way to work.

SOAP vs REST (differences)

SOAP (Simple Object Access Protocol) and REST (Representation State Transfer) both are beautiful in their way. So I am not comparing them. Instead, I am trying to depict the picture, when I preferred to use REST and when SOAP.

What is payload?

When data is sent over the Internet, each unit transmitted includes both header information and the actual data being sent. The header identifies the source and destination of the packet, while the actual data is referred to as the payload. In general, the payload is the data that is carried on behalf of an application and the data received by the destination system.

Now, for example, I have to send a Telegram and we all know that the cost of the telegram will depend on some words.

So tell me among below mentioned these two messages, which one is cheaper to send?

<name>Arin</name>

or

"name": "Arin"

I know your answer will be the second one although both representing the same message second one is cheaper regarding cost.

So I am trying to say that, sending data over the network in JSON format is cheaper than sending it in XML format regarding payload.

Here is the first benefit or advantages of REST over SOAP. SOAP only support XML, but REST supports different format like text, JSON, XML, etc. And we already know, if we use Json then definitely we will be in better place regarding payload.

Now, SOAP supports the only XML, but it also has its advantages.

Really! How?

SOAP relies on XML in three ways Envelope – that defines what is in the message and how to process it.

A set of encoding rules for data types, and finally the layout of the procedure calls and responses gathered.

This envelope is sent via a transport (HTTP/HTTPS), and an RPC (Remote Procedure Call) is executed, and the envelope is returned with information in an XML formatted document.

The important point is that one of the advantages of SOAP is the use of the “generic” transport but REST uses HTTP/HTTPS. SOAP can use almost any transport to send the request but REST cannot. So here we got an advantage of using SOAP.

As I already mentioned in above paragraph “REST uses HTTP/HTTPS”, so go a bit deeper on these words.

When we are talking about REST over HTTP, all security measures applied HTTP are inherited, and this is known as transport level security and it secures messages only while it is inside the wire but once you delivered it on the other side you don’t know how many stages it will have to go through before reaching the real point where the data will be processed. And of course, all those stages could use something different than HTTP.So Rest is not safer completely, right?

But SOAP supports SSL just like REST additionally it also supports WS-Security which adds some enterprise security features. WS-Security offers protection from the creation of the message to it’s consumption. So for transport level security whatever loophole we found that can be prevented using WS-Security.

Apart from that, as REST is limited by it's HTTP protocol so it’s transaction support is neither ACID compliant nor can provide two-phase commit across distributed transnational resources.

But SOAP has comprehensive support for both ACID based transaction management for short-lived transactions and compensation based transaction management for long-running transactions. It also supports two-phase commit across distributed resources.

I am not drawing any conclusion, but I will prefer SOAP-based web service while security, transaction, etc. are the main concerns.

Here is the "The Java EE 6 Tutorial" where they have said A RESTful design may be appropriate when the following conditions are met. Have a look.

Hope you enjoyed reading my answer.

NoClassDefFoundError: org/slf4j/impl/StaticLoggerBinder

Copy all order entries of home folder .iml file into your /src/main/main.iml file. This will solve the problem.

Install Android App Bundle on device

Short answer:

Not directly.

Longer answer:

Android App Bundles is a publishing format. Android devices require .apk files to install applications.

The PlayStore or any other source that you're installing from needs to extract apks from the bundle, sign each one and then install them specific to the target device.

The conversion from .aab to .apk is done via bundletool.

You can use Internal App Sharing to upload a debuggable build of your app to the Play Store and share it with testers.

iOS8 Beta Ad-Hoc App Download (itms-services)

I was struggling with this, my app was installing but not complete (almost 60% I can say) in iOS8, but in iOS7.1 it was working as expected. The error message popped was:

"Cannot install at this time". 

Finally Zillan's link helped me to get apple documentation. So, check:

  1. make sure the internet reachability in your device as you will be in local network/ intranet.
  2. Also make sure the address ax.init.itunes.apple.com is not getting blocked by your firewall/proxy (Just type this address in safari, a blank page must load).

As soon as I changed the proxy it installed completely. Hope it will help someone.

How do I find the location of my Python site-packages directory?

A solution that:

  • outside of virtualenv - provides the path of global site-packages,
  • insidue a virtualenv - provides the virtualenv's site-packages

...is this one-liner:

python -c "from distutils.sysconfig import get_python_lib; print(get_python_lib())"

Formatted for readability (rather than use as a one-liner), that looks like the following:

from distutils.sysconfig import get_python_lib
print(get_python_lib())


Source: an very old version of "How to Install Django" documentation (though this is useful to more than just Django installation)

How can I get System variable value in Java?

Use the System.getenv(String) method, passing the name of the variable to read.

How to compare objects by multiple fields

Better late than never - if you're looking for unnecessary clutter or overhead then it's hard to beat the following in terms of least code/fast execution at the same time.

Data class:

public class MyData {
    int id;
    boolean relevant;
    String name;
    float value;
}

Comparator:

public class MultiFieldComparator implements Comparator<MyData> {
    @Override
    public int compare(MyData dataA, MyData dataB) {
        int result;
        if((result = Integer.compare(dataA.id, dataB.id)) == 0 &&
           (result = Boolean.compare(dataA.relevant, dataB.relevant)) == 0 &&
           (result = dataA.name.compareTo(dataB.name)) == 0)
            result = Float.compare(dataA.value, dataB.value);
        return result;
    }
}

If you are just looking to sort a collection by a custom order then the following is even cleaner:

myDataList.sort((dataA, dataB) -> {
    int result;
    if((result = Integer.compare(dataA.id, dataB.id)) == 0 &&
       (result = Boolean.compare(dataA.relevant, dataB.relevant)) == 0 &&
       (result = dataA.name.compareTo(dataB.name)) == 0)
        result = Float.compare(dataA.value, dataB.value);
    return result;
});

SQL ON DELETE CASCADE, Which Way Does the Deletion Occur?

Cascade will work when you delete something on table Courses. Any record on table BookCourses that has reference to table Courses will be deleted automatically.

But when you try to delete on table BookCourses only the table itself is affected and not on the Courses

follow-up question: why do you have CourseID on table Category?

Maybe you should restructure your schema into this,

CREATE TABLE Categories 
(
  Code CHAR(4) NOT NULL PRIMARY KEY,
  CategoryName VARCHAR(63) NOT NULL UNIQUE
);

CREATE TABLE Courses 
(
  CourseID INT NOT NULL PRIMARY KEY,
  BookID INT NOT NULL,
  CatCode CHAR(4) NOT NULL,
  CourseNum CHAR(3) NOT NULL,
  CourseSec CHAR(1) NOT NULL,
);

ALTER TABLE Courses
ADD FOREIGN KEY (CatCode)
REFERENCES Categories(Code)
ON DELETE CASCADE;

Android: How can I get the current foreground activity (from a service)?

I don't know if it's a stupid answer, but resolved this problem by storing a flag in shared preferences every time I entered onCreate() of any activity, then I used the value from shered preferences to find out what it's the foreground activity.

DateTime vs DateTimeOffset

The most important distinction is that DateTime does not store time zone information, while DateTimeOffset does.

Although DateTime distinguishes between UTC and Local, there is absolutely no explicit time zone offset associated with it. If you do any kind of serialization or conversion, the server's time zone is going to be used. Even if you manually create a local time by adding minutes to offset a UTC time, you can still get bit in the serialization step, because (due to lack of any explicit offset in DateTime) it will use the server's time zone offset.

For example, if you serialize a DateTime value with Kind=Local using Json.Net and an ISO date format, you'll get a string like 2015-08-05T07:00:00-04. Notice that last part (-04) had nothing to do with your DateTime or any offset you used to calculate it... it's just purely the server's time zone offset.

Meanwhile, DateTimeOffset explicitly includes the offset. It may not include the name of the time zone, but at least it includes the offset, and if you serialize it, you're going to get the explicitly included offset in your value instead of whatever the server's local time happens to be.

from jquery $.ajax to angular $http

We can implement ajax request by using http service in AngularJs, which helps to read/load data from remote server.

$http service methods are listed below,

 $http.get()
 $http.post()
 $http.delete()
 $http.head()
 $http.jsonp()
 $http.patch()
 $http.put()

One of the Example:

    $http.get("sample.php")
        .success(function(response) {
            $scope.getting = response.data; // response.data is an array
    }).error(){

        // Error callback will trigger
    });

http://www.drtuts.com/ajax-requests-angularjs/

How to draw a graph in LaTeX?

In my experience, I always just use an external program to generate the graph (mathematica, gnuplot, matlab, etc.) and export the graph as a pdf or eps file. Then I include it into the document with includegraphics.

How to send json data in POST request using C#

This works for me.

var httpWebRequest = (HttpWebRequest)WebRequest.Create("http://url");
httpWebRequest.ContentType = "application/json";
httpWebRequest.Method = "POST";
using (var streamWriter = new 

StreamWriter(httpWebRequest.GetRequestStream()))
{
    string json = new JavaScriptSerializer().Serialize(new
                {
                    Username = "myusername",
                    Password = "password"
                });

    streamWriter.Write(json);
}
var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
{
    var result = streamReader.ReadToEnd();
}

What is the difference between "JPG" / "JPEG" / "PNG" / "BMP" / "GIF" / "TIFF" Image?

The named ones are all raster graphics, but beside that don't forget the more and more important vectorgraphics. There are compressed and uncompressed types (in a more or less way), but they're all lossless. Most important are:

How to use local docker images with Minikube?

A simpler method that answers the original question "How to use local docker images with Minikube?", is to save the image to a tar file and load it into minikube:

# export the docker image to a tar file
docker save --output my-image.tar the.full.path.to/the/docker/image:the-tag
# set local environment variables so that docker commands go to the docker in minikube
eval $(minikube docker-env)
# or if on windows: @FOR /f "tokens=*" %i IN ('minikube docker-env') DO @%i
# import the docker image from the tar file into minikube
docker load --input my-image.tar
# cleanup - put docker back to normal
eval $(minikube docker-env -u)
# or if on windows: @FOR /f "tokens=*" %i IN ('minikube docker-env -u') DO @%i

Then running the image involves a command like the following. Make sure to include the "--image-pull-policy=Never" parameter.

kubectl run my-image --image=the.full.path.to/the/docker/image:the-tag --image-pull-policy=Never --port=80

Emulate a 403 error page

Use ModRewrite:

RewriteRule ^403.html$ - [F]

Just make sure you create a blank document called "403.html" in your www root or you'll get a 404 error instead of 403.

How to get CSS to select ID that begins with a string (not in Javascript)?

I'd do it like this:

[id^="product"] {
  ...
}

Ideally, use a class. This is what classes are for:

<div id="product176" class="product"></div>
<div id="product177" class="product"></div>
<div id="product178" class="product"></div>

And now the selector becomes:

.product {
  ...
}

How to use Visual Studio C++ Compiler?

In Visual Studio, you can't just open a .cpp file and expect it to run. You must create a project first, or open the .cpp in some existing project.

In your case, there is no project, so there is no project to build.

Go to File --> New --> Project --> Visual C++ --> Win32 Console Application. You can uncheck "create a directory for solution". On the next page, be sure to check "Empty project".

Then, You can add .cpp files you created outside the Visual Studio by right clicking in the Solution explorer on folder icon "Source" and Add->Existing Item.

Obviously You can create new .cpp this way too (Add --> New). The .cpp file will be created in your project directory.

Then you can press ctrl+F5 to compile without debugging and can see output on console window.

How to get current date & time in MySQL?

Use CURRENT_TIMESTAMP() or now()

Like

INSERT INTO servers (server_name, online_status, exchange, disk_space,
network_shares,date_time) VALUES('m1','ONLINE','ONLINE','100GB','ONLINE',now() )

or

INSERT INTO servers (server_name, online_status, exchange, disk_space,
network_shares,date_time) VALUES('m1', 'ONLINE', 'ONLINE', '100GB', 'ONLINE'
,CURRENT_TIMESTAMP() )

Replace date_time with the column name you want to use to insert the time.

Explain ExtJS 4 event handling

Let's start by describing DOM elements' event handling.

DOM node event handling

First of all you wouldn't want to work with DOM node directly. Instead you probably would want to utilize Ext.Element interface. For the purpose of assigning event handlers, Element.addListener and Element.on (these are equivalent) were created. So, for example, if we have html:

<div id="test_node"></div>

and we want add click event handler.
Let's retrieve Element:

var el = Ext.get('test_node');

Now let's check docs for click event. It's handler may have three parameters:

click( Ext.EventObject e, HTMLElement t, Object eOpts )

Knowing all this stuff we can assign handler:

//       event name      event handler
el.on(    'click'        , function(e, t, eOpts){
  // handling event here
});

Widgets event handling

Widgets event handling is pretty much similar to DOM nodes event handling.

First of all, widgets event handling is realized by utilizing Ext.util.Observable mixin. In order to handle events properly your widget must containg Ext.util.Observable as a mixin. All built-in widgets (like Panel, Form, Tree, Grid, ...) has Ext.util.Observable as a mixin by default.

For widgets there are two ways of assigning handlers. The first one - is to use on method (or addListener). Let's for example create Button widget and assign click event to it. First of all you should check event's docs for handler's arguments:

click( Ext.button.Button this, Event e, Object eOpts )

Now let's use on:

var myButton = Ext.create('Ext.button.Button', {
  text: 'Test button'
});
myButton.on('click', function(btn, e, eOpts) {
  // event handling here
  console.log(btn, e, eOpts);
});

The second way is to use widget's listeners config:

var myButton = Ext.create('Ext.button.Button', {
  text: 'Test button',
  listeners : {
    click: function(btn, e, eOpts) {
      // event handling here
      console.log(btn, e, eOpts);
    }
  }
});

Notice that Button widget is a special kind of widgets. Click event can be assigned to this widget by using handler config:

var myButton = Ext.create('Ext.button.Button', {
  text: 'Test button',
  handler : function(btn, e, eOpts) {
    // event handling here
    console.log(btn, e, eOpts);
  }
});

Custom events firing

First of all you need to register an event using addEvents method:

myButton.addEvents('myspecialevent1', 'myspecialevent2', 'myspecialevent3', /* ... */);

Using the addEvents method is optional. As comments to this method say there is no need to use this method but it provides place for events documentation.

To fire your event use fireEvent method:

myButton.fireEvent('myspecialevent1', arg1, arg2, arg3, /* ... */);

arg1, arg2, arg3, /* ... */ will be passed into handler. Now we can handle your event:

myButton.on('myspecialevent1', function(arg1, arg2, arg3, /* ... */) {
  // event handling here
  console.log(arg1, arg2, arg3, /* ... */);
});

It's worth mentioning that the best place for inserting addEvents method call is widget's initComponent method when you are defining new widget:

Ext.define('MyCustomButton', {
  extend: 'Ext.button.Button',
  // ... other configs,
  initComponent: function(){
    this.addEvents('myspecialevent1', 'myspecialevent2', 'myspecialevent3', /* ... */);
    // ...
    this.callParent(arguments);
  }
});
var myButton = Ext.create('MyCustomButton', { /* configs */ });

Preventing event bubbling

To prevent bubbling you can return false or use Ext.EventObject.preventDefault(). In order to prevent browser's default action use Ext.EventObject.stopPropagation().

For example let's assign click event handler to our button. And if not left button was clicked prevent default browser action:

myButton.on('click', function(btn, e){
  if (e.button !== 0)
    e.preventDefault();
});

IEnumerable vs List - What to Use? How do they work?

I will share one misused concept that I fell into one day:

var names = new List<string> {"mercedes", "mazda", "bmw", "fiat", "ferrari"};

var startingWith_M = names.Where(x => x.StartsWith("m"));

var startingWith_F = names.Where(x => x.StartsWith("f"));


// updating existing list
names[0] = "ford";

// Guess what should be printed before continuing
print( startingWith_M.ToList() );
print( startingWith_F.ToList() );

Expected result

// I was expecting    
print( startingWith_M.ToList() ); // mercedes, mazda
print( startingWith_F.ToList() ); // fiat, ferrari

Actual result

// what printed actualy   
print( startingWith_M.ToList() ); // mazda
print( startingWith_F.ToList() ); // ford, fiat, ferrari

Explanation

As per other answers, the evaluation of the result was deferred until calling ToList or similar invocation methods for example ToArray.

So I can rewrite the code in this case as:

var names = new List<string> {"mercedes", "mazda", "bmw", "fiat", "ferrari"};

// updating existing list
names[0] = "ford";

// before calling ToList directly
var startingWith_M = names.Where(x => x.StartsWith("m"));

var startingWith_F = names.Where(x => x.StartsWith("f"));

print( startingWith_M.ToList() );
print( startingWith_F.ToList() );

Play arround

https://repl.it/E8Ki/0

General guidelines to avoid memory leaks in C++

If you are going to manage your memory manually, you have two cases:

  1. I created the object (perhaps indirectly, by calling a function that allocates a new object), I use it (or a function I call uses it), then I free it.
  2. Somebody gave me the reference, so I should not free it.

If you need to break any of these rules, please document it.

It is all about pointer ownership.

What are the differences in die() and exit() in PHP?

This output from https://3v4l.org demonstrates that die and exit are functionally identical. enter image description here

Python vs Bash - In which kind of tasks each one outruns the other performance-wise?

I'm posting this late answer primarily because Google likes this question.

I believe the issue and context really should be about the workflow, not the tools. The overall philosophy is always "Use the right tool for the job." But before this comes one that many often forget when they get lost in the tools: "Get the job done."

When I have a problem that isn't completely defined, I almost always start with Bash. I have solved some gnarly problems in large Bash scripts that are both readable and maintainable.

But when does the problem start to exceed what Bash should be asked to do? I have some checks I use to give me warnings:

  1. Am I wishing Bash had 2D (or higher) arrays? If yes, it's time to realize that Bash is not a great data processing language.
  2. Am I doing more work preparing data for other utilities than I am actually running those utilities? If yes, time again to realize Bash is not a great data processing language.
  3. Is my script simply getting too large to manage? If yes, it is important to realize that while Bash can import script libraries, it lacks a package system like other languages. It's really a "roll your own" language compared to most others. Then again, it has a enormous amount of functionality built-in (some say too much...)

The list goes on. Bottom-line, when you are working harder to keep your scripts running that you do adding features, it's time to leave Bash.

Let's assume you've decided to move your work to Python. If your Bash scripts are clean, the initial conversion is quite straightforward. There are even several converters / translators that will do the first pass for you.

The next question is: What do you give up moving to Python?

  1. All calls to external utilities must be wrapped in something from the subprocess module (or equivalent). There are multiple ways to do this, and until 3.7 it took some effort to get it right (3.7 improved subprocess.run() to handle all common cases on its own).

  2. Surprisingly, Python has no standard platform-independent non-blocking utility (with timeout) for polling the keyboard (stdin). The Bash read command is an awesome tool for simple user interaction. My most common use is to show a spinner until the user presses a key, while also running a polling function (with each spinner step) to make sure things are still running well. This is a harder problem than it would appear at first, so I often simply make a call to Bash: Expensive, but it does precisely what I need.

  3. If you are developing on an embedded or memory-constrained system, Python's memory footprint can be many times larger than Bash's (depending on the task at hand). Plus, there is almost always an instance of Bash already in memory, which may not be the case for Python.

  4. For scripts that run once and exit quickly, Python's startup time can be much longer than Bash's. But if the script contains significant calculations, Python quickly pulls ahead.

  5. Python has the most comprehensive package system on the planet. When Bash gets even slightly complex, Python probably has a package that makes whole chunks of Bash become a single call. However, finding the right package(s) to use is the biggest and most daunting part of becoming a Pythonista. Fortunately, Google and StackExchange are your friends.