Programs & Examples On #Coldfusion

ColdFusion is a server-side rapid application development platform, implementing the dynamic general purpose CFML programming language. Please include CFML version, OS & web server in questions.

How to pass "Null" (a real surname!) to a SOAP web service in ActionScript 3

Translate all characters into their hex-entity equivalents. In this case, Null would be converted into &#4E;K&#6C;&#6C;

How can I create a blank/hardcoded column in a sql query?

The answers above are correct, and what I'd consider the "best" answers. But just to be as complete as possible, you can also do this directly in CF using queryAddColumn.

See http://www.cfquickdocs.com/cf9/#queryaddcolumn

Again, it's more efficient to do it at the database level... but it's good to be aware of as many alternatives as possible (IMO, of course) :)

Keytool is not recognized as an internal or external command

Execute following command:

set PATH="C:\Program Files (x86)\Java\jre7"

(whichever JRE exists in case of 64bit).

Because your Java Path is not set so you can just do this at command line and then execute the keytool import command.

Concatenating variables and strings in React

You're almost correct, just misplaced a few quotes. Wrapping the whole thing in regular quotes will literally give you the string #demo + {this.state.id} - you need to indicate which are variables and which are string literals. Since anything inside {} is an inline JSX expression, you can do:

href={"#demo" + this.state.id}

This will use the string literal #demo and concatenate it to the value of this.state.id. This can then be applied to all strings. Consider this:

var text = "world";

And this:

{"Hello " + text + " Andrew"}

This will yield:

Hello world Andrew 

You can also use ES6 string interpolation/template literals with ` (backticks) and ${expr} (interpolated expression), which is closer to what you seem to be trying to do:

href={`#demo${this.state.id}`}

This will basically substitute the value of this.state.id, concatenating it to #demo. It is equivalent to doing: "#demo" + this.state.id.

Animate visibility modes, GONE and VISIBLE

You can use the expandable list view explained in API demos to show groups

http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/view/ExpandableList1.html.

To animate the list items motion, you will have to override the getView method and apply translate animation on each list item. The values for animation depend on the position of each list item. This was something which i tried on a simple list view long time back.

What's the difference between a null pointer and a void pointer?

Void refers to the type. Basically the type of data that it points to is unknown.

Null refers to the value. It's essentially a pointer to nothing, and is invalid to use.

virtualenvwrapper and Python 3

You can make virtualenvwrapper use a custom Python binary instead of the one virtualenvwrapper is run with. To do that you need to use VIRTUALENV_PYTHON variable which is utilized by virtualenv:

$ export VIRTUALENV_PYTHON=/usr/bin/python3
$ mkvirtualenv -a myproject myenv
Running virtualenv with interpreter /usr/bin/python3
New python executable in myenv/bin/python3
Also creating executable in myenv/bin/python
(myenv)$ python
Python 3.2.3 (default, Oct 19 2012, 19:53:16) 
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.

auto create database in Entity Framework Core

If you want both of EnsureCreated and Migrate use this code:

     using (var context = new YourDbContext())
            {
                if (context.Database.EnsureCreated())
                {
                    //auto migration when database created first time

                    //add migration history table

                    string createEFMigrationsHistoryCommand = $@"
USE [{context.Database.GetDbConnection().Database}];
SET ANSI_NULLS ON;
SET QUOTED_IDENTIFIER ON;
CREATE TABLE [dbo].[__EFMigrationsHistory](
    [MigrationId] [nvarchar](150) NOT NULL,
    [ProductVersion] [nvarchar](32) NOT NULL,
 CONSTRAINT [PK___EFMigrationsHistory] PRIMARY KEY CLUSTERED 
(
    [MigrationId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY];
";
                    context.Database.ExecuteSqlRaw(createEFMigrationsHistoryCommand);

                    //insert all of migrations
                    var dbAssebmly = context.GetType().GetAssembly();
                    foreach (var item in dbAssebmly.GetTypes())
                    {
                        if (item.BaseType == typeof(Migration))
                        {
                            string migrationName = item.GetCustomAttributes<MigrationAttribute>().First().Id;
                            var version = typeof(Migration).Assembly.GetName().Version;
                            string efVersion = $"{version.Major}.{version.Minor}.{version.Build}";
                            context.Database.ExecuteSqlRaw("INSERT INTO __EFMigrationsHistory(MigrationId,ProductVersion) VALUES ({0},{1})", migrationName, efVersion);
                        }
                    }
                }
                context.Database.Migrate();
            }

My httpd.conf is empty

It seems to me, that it is by design that this file is empty.

A similar question has been asked here: https://stackoverflow.com/questions/2567432/ubuntu-apache-httpd-conf-or-apache2-conf

So, you should have a look for /etc/apache2/apache2.conf

Can the Twitter Bootstrap Carousel plugin fade in and out on slide transition

Came across this issue when using Bootstrap 3. My solution was to add the carousel-fade class to the carousel main DIV and slot the following CSS in, somewhere after the Bootstrap CSS is included:

.carousel-fade .item {
  opacity: 0;
  -webkit-transition: opacity 2s ease-in-out;
  -moz-transition: opacity 2s ease-in-out;
  -ms-transition: opacity 2s ease-in-out;
  -o-transition: opacity 2s ease-in-out;
  transition: opacity 2s ease-in-out;
  left: 0 !important;
}

.carousel-fade .active {
  opacity: 1 !important;
}

.carousel-fade .left {
  opacity: 0 !important;
  -webkit-transition: opacity 0.5s ease-in-out !important;
  -moz-transition: opacity 0.5s ease-in-out !important;
  -ms-transition: opacity 0.5s ease-in-out !important;
  -o-transition: opacity 0.5s ease-in-out !important;
  transition: opacity 0.5s ease-in-out !important;
}

.carousel-fade .carousel-control {
  opacity: 1 !important;
}

The style transitions that Bootstrap applies mean that you have to have the mid-stride transitions (active left, next left) quickly, otherwise the item just ends up disappearing (hence the 1/2 second transition time).

I haven't experimented with adjusting the .item and .left transition times, but they will probably need adjusting proportionally to keep the effect looking nice.

How do I make a relative reference to another workbook in Excel?

What works for me was with one dot. Mine Office is 365. =HYPERLINK(".\Name_of_folder\","DisplayLinkName") =HYPERLINK(".\Name_of_file","DisplayLinkName")

Strange problem with Subversion - "File already exists" when trying to recreate a directory that USED to be in my repository

I managed to work around it by reverting back to the last version that I had the mysql directory in, then deleting the contents of the directory, putting the new contents in it, and checking the new information back in. Although I'm curious if anyone has a better explanation for what the heck was going on there.

Pass all variables from one shell script to another?

Another option is using eval. This is only suitable if the strings are trusted. The first script can echo the variable assignments:

echo "VAR=myvalue"

Then:

eval $(./first.sh) ./second.sh

This approach is of particular interest when the second script you want to set environment variables for is not in bash and you also don't want to export the variables, perhaps because they are sensitive and you don't want them to persist.

How do I execute a program using Maven?

With the global configuration that you have defined for the exec-maven-plugin:

<plugin>
  <groupId>org.codehaus.mojo</groupId>
  <artifactId>exec-maven-plugin</artifactId>
  <version>1.4.0</version>
  <configuration>
    <mainClass>org.dhappy.test.NeoTraverse</mainClass>
  </configuration>
</plugin>

invoking mvn exec:java on the command line will invoke the plugin which is configured to execute the class org.dhappy.test.NeoTraverse.

So, to trigger the plugin from the command line, just run:

mvn exec:java

Now, if you want to execute the exec:java goal as part of your standard build, you'll need to bind the goal to a particular phase of the default lifecycle. To do this, declare the phase to which you want to bind the goal in the execution element:

<plugin>
  <groupId>org.codehaus.mojo</groupId>
  <artifactId>exec-maven-plugin</artifactId>
  <version>1.4</version>
  <executions>
    <execution>
      <id>my-execution</id>
      <phase>package</phase>
      <goals>
        <goal>java</goal>
      </goals>
    </execution>
  </executions>
  <configuration>
    <mainClass>org.dhappy.test.NeoTraverse</mainClass>
  </configuration>
</plugin>

With this example, your class would be executed during the package phase. This is just an example, adapt it to suit your needs. Works also with plugin version 1.1.

uncaught syntaxerror unexpected token U JSON

This answer can be a possible solution from many. This answer is for the people who are facing this error while working with File Upload..

We were using middleware for token based encryption - decryption and we encountered same error.

Following was our code in route file:

  router.route("/uploadVideoMessage")
  .post(
    middleware.checkToken,
    upload.single("video_file"),
    videoMessageController.uploadVideoMessage
  );

here we were calling middleware before upload function and that was causing the error. So when we changed it to this, it worked.

router.route("/uploadVideoMessage")
  .post(
    upload.single("video_file"),
    middleware.checkToken,
    videoMessageController.uploadVideoMessage
  );

How to inspect FormData?

  function abc(){ 
    var form = $('#form_name')[0]; 
        var formData = new FormData(form);
        for (var [key, value] of formData.entries()) { 
            console.log(key, value);
        }
        $.ajax({
            type: "POST",
            url: " ",
            data:  formData,
            contentType: false,
            cache: false,
            processData:false,
            beforeSend: function() {

            },
            success: function(data) {


            },

       });
}

Linux command for extracting war file?

Or

jar xvf myproject.war

MySQL SELECT AS combine two columns into one

In case of NULL columns it is better to use IF clause like this which combine the two functions of : CONCAT and COALESCE and uses special chars between the columns in result like space or '_'

SELECT FirstName , LastName , 
IF(FirstName IS NULL AND LastName IS NULL, NULL,' _ ',CONCAT(COALESCE(FirstName ,''), COALESCE(LastName ,''))) 
AS Contact_Phone FROM   TABLE1

Mongoose query where value is not null

$ne

selects the documents where the value of the field is not equal to the specified value. This includes documents that do not contain the field.

User.find({ "username": { "$ne": 'admin' } })

$nin

$nin selects the documents where: the field value is not in the specified array or the field does not exist.

User.find({ "groups": { "$nin": ['admin', 'user'] } })

Manually map column names with class properties

Messing with mapping is borderline moving into real ORM land. Instead of fighting with it and keeping Dapper in its true simple (fast) form, just modify your SQL slightly like so:

var sql = @"select top 1 person_id as PersonId,FirstName,LastName from Person";

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

Try

var ts = TimeSpan.Parse(stringTime);

With a newer .NET you also have

TimeSpan ts;

if(!TimeSpan.TryParse(stringTime, out ts)){
     // throw exception or whatnot
}
// ts now has a valid format

This is the general idiom for parsing strings in .NET with the first version handling erroneous string by throwing FormatException and the latter letting the Boolean TryParse give you the information directly.

What is the difference between git clone and checkout?

Simply git checkout have 2 uses

  1. Switching between existing local branches like git checkout <existing_local_branch_name>
  2. Create a new branch from current branch using flag -b. Suppose if you are at master branch then git checkout -b <new_feature_branch_name> will create a new branch with the contents of master and switch to newly created branch

You can find more options at the official site

Room - Schema export directory is not provided to the annotation processor so we cannot export the schema

Above answers are correct. This version is easy to follow:

Because "Schema export directory is not provided to the annotation processor", So we need to provide the directory for schema export:

Step [1] In your file which extends the RoomDatabase, change the line to:

`@Database(entities = ???.class,version = 1, exportSchema = true)`

Or

`@Database(entities = ???.class,version = 1)` 

(because the default value is always true)

Step [2] In your build.gradle(project:????) file, inside the defaultConfig{ } (which is inside android{ } big section), add the javaCompileOptions{ } section, it will be like:

         android{
                defaultConfig{
                      //javaComplieOptions SECTION
                      javaCompileOptions {
                            annotationProcessorOptions {
                                     arguments = ["room.schemaLocation":"$projectDir/schemas".toString()]
                            }
                       }
                      //Other SECTION
                      ...
                }
         }

$projectDir:is a variable name, you cannot change it. it will get your own project directory

schemas:is a string, you can change it to any you like. For example: "$projectDir/MyOwnSchemas".toString()

How should the ViewModel close the form?

This is a simple and clean solution - You add an event to the ViewModel and instruct the Window to close itself when that event is fired.

For more details see my blog post, Close window from ViewModel.

XAML:

<Window
  x:Name="this"
  xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"  
  xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions">
  <i:Interaction.Triggers>
    <i:EventTrigger SourceObject="{Binding}" EventName="Closed">
      <ei:CallMethodAction
        TargetObject="{Binding ElementName=this}"
        MethodName="Close"/>
    </i:EventTrigger>
  </i:Interaction.Triggers>
<Window>

ViewModel:

private ICommand _SaveAndCloseCommand;
public ICommand SaveAndCloseCommand
{
  get
  {
    return _SaveAndCloseCommand ??
      (_SaveAndCloseCommand = new DelegateCommand(SaveAndClose));
  }
}
private void SaveAndClose()
{
  Save();
  Close();
}

public event EventHandler Closed;
private void Close()
{
  if (Closed != null) Closed(this, EventArgs.Empty);
}

Note: The example uses Prism's DelegateCommand (see Prism: Commanding), but any ICommand implementation can be used for that matter.

You can use behaviors from this official package.

Open multiple Projects/Folders in Visual Studio Code

To run one project at a time in same solution

Open Solution explorer window -> Open Solution for Project -> Right click on it -> Select Properties from drop down list (Alt+Enter)-> Common Properties -> select Startup Project you will see "current selection,single selection and multiple selection from that select "Current Selection" this will help you to run one project at a time in same solution workspace having different coding.

My Application Could not open ServletContext resource

If you are getting this error with a Java configuration, it is usually because you forget to pass in the application context to the DispatcherServlet constructor:

AnnotationConfigWebApplicationContext ctx = new AnnotationConfigWebApplicationContext();
ctx.register(WebConfig.class);

ServletRegistration.Dynamic dispatcher = sc.addServlet("dispatcher", 
    new DispatcherServlet()); // <-- no constructor args!
dispatcher.setLoadOnStartup(1);
dispatcher.addMapping("/*");

Fix it by adding the context as the constructor arg:

AnnotationConfigWebApplicationContext ctx = new AnnotationConfigWebApplicationContext();
ctx.register(WebConfig.class);

ServletRegistration.Dynamic dispatcher = sc.addServlet("dispatcher", 
    new DispatcherServlet(ctx)); // <-- hooray! Spring doesn't look for XML files!
dispatcher.setLoadOnStartup(1);
dispatcher.addMapping("/*");

How do I show a running clock in Excel?

See the below code (taken from this post)

Put this code in a Module in VBA (Developer Tab -> Visual Basic)

Dim TimerActive As Boolean
Sub StartTimer()
    Start_Timer
End Sub
Private Sub Start_Timer()
    TimerActive = True
    Application.OnTime Now() + TimeValue("00:01:00"), "Timer"
End Sub
Private Sub Stop_Timer()
    TimerActive = False
End Sub
Private Sub Timer()
    If TimerActive Then
        ActiveSheet.Cells(1, 1).Value = Time
        Application.OnTime Now() + TimeValue("00:01:00"), "Timer"
    End If
End Sub

You can invoke the "StartTimer" function when the workbook opens and have it repeat every minute by adding the below code to your workbooks Visual Basic "This.Workbook" class in the Visual Basic editor.

Private Sub Workbook_Open()
    Module1.StartTimer
End Sub

Now, every time 1 minute passes the Timer procedure will be invoked, and set cell A1 equal to the current time.

Run a Docker image as a container

The specific way to run it depends on whether you gave the image a tag/name or not.

$ docker images
REPOSITORY          TAG                 ID                  CREATED             SIZE
ubuntu              12.04               8dbd9e392a96        4 months ago        131.5 MB (virtual 131.5 MB)

With a name (let's use Ubuntu):

$ docker run -i -t ubuntu:12.04 /bin/bash

Without a name, just using the ID:

$ docker run -i -t 8dbd9e392a96 /bin/bash

Please see Docker run reference for more information.

How to programmatically open the Permission Screen for a specific app on Android Marshmallow?

It is not possible to programmatically open the permission screen. Instead, we can open the app settings screen.

Code

Intent i = new Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.parse("package:" + BuildConfig.APPLICATION_ID));
startActivity(i);

Sample Output

enter image description here

Determine on iPhone if user has enabled push notifications

Unfortunately none of these solutions provided really solve the problem because at the end of the day the APIs are seriously lacking when it comes to providing the pertinent information. You can make a few guesses however using currentUserNotificationSettings (iOS8+) just isn't sufficient in its current form to really answer the question. Although a lot of the solutions here seem to suggest that either that or isRegisteredForRemoteNotifications is more of a definitive answer it really is not.

Consider this:

with isRegisteredForRemoteNotifications documentation states:

Returns YES if the application is currently registered for remote notifications, taking into account any systemwide settings...

However if you throw a simply NSLog into your app delegate to observe the behavior it is clear this does not behave the way we are anticipating it will work. It actually pertains directly to remote notifications having been activated for this app/device. Once activated for the first time this will always return YES. Even turning them off in settings (notifications) will still result in this returning YES this is because, as of iOS8, an app may register for remote notifications and even send to a device without the user having notifications enabled, they just may not do Alerts, Badges and Sound without the user turning that on. Silent notifications are a good example of something you may continue to do even with notifications turned off.

As far as currentUserNotificationSettings it indicates one of four things:

Alerts are on Badges are on Sound is on None are on.

This gives you absolutely no indication whatsoever about the other factors or the Notification switch itself.

A user may in fact turn off badges, sound and alerts but still have show on lockscreen or in notification center. This user should still be receiving push notifications and be able to see them both on the lock screen and in the notification center. They have the notification switch on. BUT currentUserNotificationSettings will return: UIUserNotificationTypeNone in that case. This is not truly indicative of the users actual settings.

A few guesses one can make:

  • if isRegisteredForRemoteNotifications is NO then you can assume that this device has never successfully registered for remote notifications.
  • after the first time of registering for remote notifications a callback to application:didRegisterUserNotificationSettings: is made containing user notification settings at this time since this is the first time a user has been registered the settings should indicate what the user selected in terms of the permission request. If the settings equate to anything other than: UIUserNotificationTypeNone then push permission was granted, otherwise it was declined. The reason for this is that from the moment you begin the remote registration process the user only has the ability to accept or decline, with the initial settings of an acceptance being the settings you setup during the registration process.

SSH Private Key Permissions using Git GUI or ssh-keygen are too open

For Windows 7 using the Git found here (it uses MinGW, not Cygwin):

  1. In the windows explorer, right-click your id_rsa file and select Properties
  2. Select the Security tab and click Edit...
  3. Check the Deny box next to Full Control for all groups EXCEPT Administrators
  4. Retry your Git command

System.Net.Http: missing from namespace? (using .net 4.5)

Make sure it's referenced in your web.config:

How do I output text without a newline in PowerShell?

Unfortunately, as noted in several answers and comments, Write-Host can be dangerous and cannot be piped to other processes and Write-Output does not have the -NoNewline flag.

But those methods are the "*nix" ways to display progression, the "PowerShell" way to do that seems to be Write-Progress: it displays a bar at the top of the PowerShell window with progress information, available from PowerShell 3.0 onward, see manual for details.

# Total time to sleep
$start_sleep = 120

# Time to sleep between each notification
$sleep_iteration = 30

Write-Output ( "Sleeping {0} seconds ... " -f ($start_sleep) )
for ($i=1 ; $i -le ([int]$start_sleep/$sleep_iteration) ; $i++) {
    Start-Sleep -Seconds $sleep_iteration
    Write-Progress -CurrentOperation ("Sleep {0}s" -f ($start_sleep)) ( " {0}s ..." -f ($i*$sleep_iteration) )
}
Write-Progress -CurrentOperation ("Sleep {0}s" -f ($start_sleep)) -Completed "Done waiting for X to finish"

And to take the OP's example:

# For the file log
Write-Output "Enabling feature XYZ"

# For the operator
Write-Progress -CurrentOperation "EnablingFeatureXYZ" ( "Enabling feature XYZ ... " )

Enable-SPFeature...

# For the operator
Write-Progress -CurrentOperation "EnablingFeatureXYZ" ( "Enabling feature XYZ ... Done" )

# For the log file
Write-Output "Feature XYZ enabled"

Web API Put Request generates an Http 405 Method Not Allowed error

Another cause of this could be if you don't use the default variable name for the "id" which is actually: id.

htaccess Access-Control-Allow-Origin

The other answers didn't work for me, this is what ended up doing the trick for apache2:

1) Enable the headers mod:

sudo a2enmod headers

2) Create the /etc/apache2/mods-enabled/headers.conf file and insert:

<IfModule mod_headers.c>
    Header set Access-Control-Allow-Origin "*"
</IfModule>

3) Restart your server:

sudo service apache2 restart

Port 80 is being used by SYSTEM (PID 4), what is that?

I just got this problem today, since it showed up after Norton requested reboot I blamed Norton.
But it wasn't Norton, I removed Norton, rebooted -> problem still there.

netstat -nao was showing that PID 4 owned my port 80 connection.

I then went to control panel, then "Turn Windows features on or off" then unchecked Internet Information Services.
Rebooted, the problem went away.
My xampp server is running ok now.

I don't ever remembering turning IIS on in the first place. I had been running many months before this happened. I still don't know what caused it in the first place. Maybe a previous windows updated enabled iis and my reboot turned it on, I don't know.

How can I find the method that called the current method?

Obviously this is a late answer, but I have a better option if you can use .NET 4.5 or newer:

internal static void WriteInformation<T>(string text, [CallerMemberName]string method = "")
{
    Console.WriteLine(DateTime.Now.ToString() + " => " + typeof(T).FullName + "." + method + ": " + text);
}

This will print the current Date and Time, followed by "Namespace.ClassName.MethodName" and ending with ": text".
Sample output:

6/17/2016 12:41:49 PM => WpfApplication.MainWindow..ctor: MainWindow initialized

Sample use:

Logger.WriteInformation<MainWindow>("MainWindow initialized");

Is a new line = \n OR \r\n?

The given answer is far from complete. In fact, it is so far from complete that it tends to lead the reader to believe that this answer is OS dependent when it isn't. It also isn't something which is programming language dependent (as some commentators have suggested). I'm going to add more information in order to make this more clear. First, lets give the list of current new line variations (as in, what they've been since 1999):

  • \r\n is only used on Windows Notepad, the DOS command line, most of the Windows API and in some (older) Windows apps.
  • \n is used for all other systems, applications and the Internet.

You'll notice that I've put most Windows apps in the \n group which may be slightly controversial but before you disagree with this statement, please grab a UNIX formatted text file and try it in 10 web friendly Windows applications of your choice (which aren't listed in my exceptions above). What percentage of them handled it just fine? You'll find that they (practically) all implement auto detection of line endings or just use \n because, while Windows may use \r\n, the Internet uses \n. Therefore, it is best practice for applications to use \n alone if you want your output to be Internet friendly.

PHP also defines a newline character called PHP_EOL. This constant is set to the OS specific newline string for the machine PHP is running on (\r\n for Windows and \n for everything else). This constant is not very useful for webpages and should be avoided for HTML output or for writing most text to files. It becomes VERY useful when we move to command line output from PHP applications because it will allow your application to output to a terminal Window in a consistent manner across all supported OSes.

If you want your PHP applications to work from any server they are placed on, the two biggest things to remember are that you should always just use \n unless it is terminal output (in which case you use PHP_EOL) and you should also ALWAYS use / for your path separator (not \).

The even longer explanation:

An application may choose to use whatever line endings it likes regardless of the default OS line ending style. If I want my text editor to print a newline every time it encounters a period that is no harder than using the \n to represent a newline because I'm interpreting the text as I display it anyway. IOW, I'm fiddling around with measuring the width of each character so it knows where to display the next so it is very simple to add a statement saying that if the current char is a period then perform a newline action (or if it is a \n then display a period).

Aside from the null terminator, no character code is sacred and when you write a text editor or viewer you are in charge of translating the bits in your file into glyphs (or carriage returns) on the screen. The only thing that distinguishes a control character such as the newline from other characters is that most font sets don't include them (meaning they don't have a visual representation available).

That being said, if you are working at a higher level of abstraction then you probably aren't making your own textbox controls. If this is the case then you're stuck with whatever line ending that control makes available to you. Even in this case it is a simple matter to automatically detect the line ending style of any string and make the conversion before you load your text into the control and then undo it when you read from that control. Meaning, that if you're a desktop application dev and your application doesn't recognize \n as a newline then it isn't a very friendly application and you really have no excuse because it isn't hard to make it the right way. It also means that whomever wrote Notepad should be ashamed of himself because it really is very easy to do much better and so many people suffer through using it every day.

Find the number of columns in a table

Query to count the number of columns in a table:

select count(*) from user_tab_columns where table_name = 'tablename';

Replace tablename with the name of the table whose total number of columns you want returned.

Java IOException "Too many open files"

On Linux and other UNIX / UNIX-like platforms, the OS places a limit on the number of open file descriptors that a process may have at any given time. In the old days, this limit used to be hardwired1, and relatively small. These days it is much larger (hundreds / thousands), and subject to a "soft" per-process configurable resource limit. (Look up the ulimit shell builtin ...)

Your Java application must be exceeding the per-process file descriptor limit.

You say that you have 19 files open, and that after a few hundred times you get an IOException saying "too many files open". Now this particular exception can ONLY happen when a new file descriptor is requested; i.e. when you are opening a file (or a pipe or a socket). You can verify this by printing the stacktrace for the IOException.

Unless your application is being run with a small resource limit (which seems unlikely), it follows that it must be repeatedly opening files / sockets / pipes, and failing to close them. Find out why that is happening and you should be able to figure out what to do about it.

FYI, the following pattern is a safe way to write to files that is guaranteed not to leak file descriptors.

Writer w = new FileWriter(...);
try {
    // write stuff to the file
} finally {
    try {
        w.close();
    } catch (IOException ex) {
        // Log error writing file and bail out.
    }
}

1 - Hardwired, as in compiled into the kernel. Changing the number of available fd slots required a recompilation ... and could result in less memory being available for other things. In the days when Unix commonly ran on 16-bit machines, these things really mattered.

UPDATE

The Java 7 way is more concise:

try (Writer w = new FileWriter(...)) {
    // write stuff to the file
} // the `w` resource is automatically closed 

UPDATE 2

Apparently you can also encounter a "too many files open" while attempting to run an external program. The basic cause is as described above. However, the reason that you encounter this in exec(...) is that the JVM is attempting to create "pipe" file descriptors that will be connected to the external application's standard input / output / error.

How can I catch all the exceptions that will be thrown through reading and writing a file?

You may catch multiple exceptions in single catch block.

try{
  // somecode throwing multiple exceptions;
} catch (Exception1 | Exception2 | Exception3 exception){
  // handle exception.
} 

Difference between a theta join, equijoin and natural join

@outis's answer is good: concise and correct as regards relations.

However, the situation is slightly more complicated as regards SQL.

Consider the usual suppliers and parts database but implemented in SQL:

SELECT * FROM S NATURAL JOIN SP;

would return a resultset** with columns

SNO, SNAME, STATUS, CITY, PNO, QTY

The join is performed on the column with the same name in both tables, SNO. Note that the resultset has six columns and only contains one column for SNO.

Now consider a theta eqijoin, where the column names for the join must be explicitly specified (plus range variables S and SP are required):

SELECT * FROM S JOIN SP ON S.SNO = SP.SNO;

The resultset will have seven columns, including two columns for SNO. The names of the resultset are what the SQL Standard refers to as "implementation dependent" but could look like this:

SNO, SNAME, STATUS, CITY, SNO, PNO, QTY

or perhaps this

S.SNO, SNAME, STATUS, CITY, SP.SNO, PNO, QTY

In other words, NATURAL JOIN in SQL can be considered to remove columns with duplicated names from the resultset (but alas will not remove duplicate rows - you must remember to change SELECT to SELECT DISTINCT yourself).


** I don't quite know what the result of SELECT * FROM table_expression; is. I know it is not a relation because, among other reasons, it can have columns with duplicate names or a column with no name. I know it is not a set because, among other reasons, the column order is significant. It's not even a SQL table or SQL table expression. I call it a resultset.

Increment a value in Postgres

UPDATE totals 
   SET total = total + 1
WHERE name = 'bill';

If you want to make sure the current value is indeed 203 (and not accidently increase it again) you can also add another condition:

UPDATE totals 
   SET total = total + 1
WHERE name = 'bill'
  AND total = 203;

In mocha testing while calling asynchronous function how to avoid the timeout Error: timeout of 2000ms exceeded

I find that the "solution" of just increasing the timeouts obscures what's really going on here, which is either

  1. Your code and/or network calls are way too slow (should be sub 100 ms for a good user experience)
  2. The assertions (tests) are failing and something is swallowing the errors before Mocha is able to act on them.

You usually encounter #2 when Mocha doesn't receive assertion errors from a callback. This is caused by some other code swallowing the exception further up the stack. The right way of dealing with this is to fix the code and not swallow the error.

When external code swallows your errors

In case it's a library function that you are unable to modify, you need to catch the assertion error and pass it onto Mocha yourself. You do this by wrapping your assertion callback in a try/catch block and pass any exceptions to the done handler.

it('should not fail', function (done) { // Pass reference here!

  i_swallow_errors(function (err, result) {
    try { // boilerplate to be able to get the assert failures
      assert.ok(true);
      assert.equal(result, 'bar');
      done();
    } catch (error) {
      done(error);
    }
  });
});

This boilerplate can of course be extracted into some utility function to make the test a little more pleasing to the eye:

it('should not fail', function (done) { // Pass reference here!
    i_swallow_errors(handleError(done, function (err, result) {
        assert.equal(result, 'bar');
    }));
});

// reusable boilerplate to be able to get the assert failures
function handleError(done, fn) {
    try { 
        fn();
        done();
    } catch (error) {
        done(error);
    }
}

Speeding up network tests

Other than that I suggest you pick up the advice on starting to use test stubs for network calls to make tests pass without having to rely on a functioning network. Using Mocha, Chai and Sinon the tests might look something like this

describe('api tests normally involving network calls', function() {

    beforeEach: function () {
        this.xhr = sinon.useFakeXMLHttpRequest();
        var requests = this.requests = [];

        this.xhr.onCreate = function (xhr) {
            requests.push(xhr);
        };
    },

    afterEach: function () {
        this.xhr.restore();
    }


    it("should fetch comments from server", function () {
        var callback = sinon.spy();
        myLib.getCommentsFor("/some/article", callback);
        assertEquals(1, this.requests.length);

        this.requests[0].respond(200, { "Content-Type": "application/json" },
                                 '[{ "id": 12, "comment": "Hey there" }]');
        expect(callback.calledWith([{ id: 12, comment: "Hey there" }])).to.be.true;
    });

});

See Sinon's nise docs for more info.

2D character array initialization in C

I think what you originally meant to do was to make an array only of characters, not of pointers:

char options[2][100];

options[0][0]='t';
options[0][1]='e';
options[0][2]='s';
options[0][3]='t';
options[0][4]='1';
options[0][5]='\0';  /* NUL termination of C string */

/* A standard C library function which copies strings. */
strcpy(options[1], "test2");

The code above shows two distinct methods of setting the character values in memory you have set aside to contain characters.

Making the Android emulator run faster

Enable GPU Hardware Acceleration (in addition to Intel's HAXM), if you are using API 15 v3 or newer and SDK Tools v17+. Graphics acceleration for the emulator takes advantage of your development computer's graphics hardware, specifically its graphics processing unit (GPU), to make screen drawing faster. This gives a noticeable boost in speed.

To enable graphics acceleration enabled by default on your emulator: when creating the AVD, in the Hardware section, click New, select GPU emulation and set the value to Yes.

To enable acceleration only at runtime: use the -gpu flag while starting the emulator like this:

emulator -avd <avd_name> -gpu on

Source: Google's Using the Emulator tutorial.

Convert UTC datetime string to local datetime

Here is a quick and dirty version that uses the local systems settings to work out the time difference. NOTE: This will not work if you need to convert to a timezone that your current system is not running in. I have tested this with UK settings under BST timezone

from datetime import datetime
def ConvertP4DateTimeToLocal(timestampValue):
   assert isinstance(timestampValue, int)

   # get the UTC time from the timestamp integer value.
   d = datetime.utcfromtimestamp( timestampValue )

   # calculate time difference from utcnow and the local system time reported by OS
   offset = datetime.now() - datetime.utcnow()

   # Add offset to UTC time and return it
   return d + offset

Will iOS launch my app into the background if it was force-quit by the user?

You can change your target's launch settings in "Manage Scheme" to Wait for <app>.app to be launched manually, which allows you debug by setting a breakpoint in application: didReceiveRemoteNotification: fetchCompletionHandler: and sending the push notification to trigger the background launch.

I'm not sure it'll solve the issue, but it may assist you with debugging for now.

screenshot

How do I implement Toastr JS?

Toastr is a very nice component, and you can show messages with theses commands:

// for success - green box
toastr.success('Success messages');

// for errors - red box
toastr.error('errors messages');

// for warning - orange box
toastr.warning('warning messages');

// for info - blue box
toastr.info('info messages');

If you want to provide a title on the toastr message, just add a second argument:

// for info - blue box
toastr.success('The process has been saved.', 'Success');

you also can change the default behaviour using something like this:

toastr.options.timeOut = 3000; // 3s

See more on the github of the project.

Edits

A sample of use:

$(document).ready(function() {

    // show when page load
    toastr.info('Page Loaded!');

    $('#linkButton').click(function() {
       // show when the button is clicked
       toastr.success('Click Button');

    });

});

and a html:

<a id='linkButton'>Show Message</a>

convert float into varchar in SQL server without scientific notation

I have another solution since the STR() function would result some blank spaces, so I use the FORMAT() function as folowing example:

SELECT ':' + STR(1000.2324422), ':' + FORMAT(1000.2324422,'##.#######'), ':' + FORMAT(1000.2324422,'##')

The result of above code would be:

:      1000 :1000.2324422   :1000

Binding List<T> to DataGridView in WinForm

After adding new item to persons add:

myGrid.DataSource = null;
myGrid.DataSource = persons;

How to make a variable accessible outside a function?

$.getJSON is an asynchronous request, meaning the code will continue to run even though the request is not yet done. You should trigger the second request when the first one is done, one of the choices you seen already in ComFreek's answer.

Alternatively you could use jQuery's $.when/.then(), similar to this:

var input = "netuetamundis";  var sID;  $(document).ready(function () {     $.when($.getJSON("https://prod.api.pvp.net/api/lol/eune/v1.1/summoner/by-name/" + input + "?api_key=API_KEY_HERE", function () {         obj = name;         sID = obj.id;         console.log(sID);     })).then(function () {         $.getJSON("https://prod.api.pvp.net/api/lol/eune/v1.2/stats/by-summoner/" + sID + "/summary?api_key=API_KEY_HERE", function (stats) {             console.log(stats);         });     }); }); 

This would be more open for future modification and separates out the responsibility for the first call to know about the second call.

The first call can simply complete and do it's own thing not having to be aware of any other logic you may want to add, leaving the coupling of the logic separated.

Adding ID's to google map markers

Marker already has unique id

marker.__gm_id

Conditional formatting based on another cell's value

change the background color of cell B5 based on the value of another cell - C5. If C5 is greater than 80% then the background color is green but if it's below, it will be amber/red.

There is no mention that B5 contains any value so assuming 80% is .8 formatted as percentage without decimals and blank counts as "below":

Select B5, colour "amber/red" with standard fill then Format - Conditional formatting..., Custom formula is and:

=C5>0.8

with green fill and Done.

CF rule example

How to open a new file in vim in a new window

If you don't mind using gVim, you can launch a single instance, so that when a new file is opened with it it's automatically opened in a new tab in the currently running instance.

to do this you can write: gVim --remote-tab-silent file

You could always make an alias to this command so that you don't have to type so many words. For example I use linux and bash and in my ~/.bashrc file I have:

alias g='gvim --remote-tab-silent'

so instead of doing $ mate file I do: $ g file

What can MATLAB do that R cannot do?

I have used both R and MATLAB to solve problems and construct models related to Environmental Engineering and there is a lot of overlap between the two systems. In my opinion, the advantages of MATLAB lie in specialized domain-specific applications. Some examples are:

  • Functions such as streamline that aid in fluid dynamics investigations.

  • Toolboxes such as the image processing toolset. I have not found a R package that provides an equivalent implementation of tools like the watershed algorithm.

In my opinion MATLAB provides far better interactive graphics capabilities. However, I think R produces better static print-quality graphics, depending on the application. MATLAB's symbolic math toolbox is also better integrated and more capable than R equivalents such as Ryacas or rSymPy. The existence of the MATLAB compiler also allows systems based on MATLAB code to be deployed independently of the MATLAB environment-- although it's availability will depend on how much money you have to throw around.

Another thing I should note is that the MATLAB debugger is one of the best I have worked with.

The principle advantage I see with R is the openness of the system and the ease with which it can be extended. This has resulted in an incredible diversity of packages on CRAN. I know Mathworks also maintains a repository of user-contributed toolboxes and I can't make a fair comparison as I have not used it that much.

The openness of R also extends to linking in compiled code. A while back I had a model written in Fortran and I was trying to decide between using R or MATLAB as a front-end to help prepare input and process results. I spent an hour reading about the MEX interface to compiled code. When I found that I would have to write and maintain a separate Fortran routine that did some intricate pointer juggling in order to manage the interface, I shelved MATLAB.

The R interface consists of calling .Fortran( [subroutine name], [argument list]) and is simply quicker and cleaner.

What, exactly, is needed for "margin: 0 auto;" to work?

Off the top of my cat's head, make sure the div you're trying to center is not set to width: 100%.

If it is, then the rules set on the child divs are what will matter.

The response content cannot be parsed because the Internet Explorer engine is not available, or

You can disable need to run Internet Explorer's first launch configuration by running this PowerShell script, it will adjust corresponding registry property:

Set-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Internet Explorer\Main" -Name "DisableFirstRunCustomize" -Value 2

After this, WebClient will work without problems

Placeholder Mixin SCSS/CSS

I use exactly the same sass mixin placeholder as NoDirection wrote. I find it in sass mixins collection here and I'm very satisfied with it. There's a text that explains a mixins option more.

Scale Image to fill ImageView width and keep aspect ratio

You can try to do what you're doing by manually loading the images, but I would very very strongly recommend taking a look at Universal Image Loader.

I recently integrated it into my project and I have to say its fantastic. Does all the worrying about making things asynchronous, resizing, caching images for you. It's really easy to integrate and set up. Within 5 minutes you can probably get it doing what you want.

Example code:

//ImageLoader config
DisplayImageOptions displayimageOptions = new DisplayImageOptions.Builder().showStubImage(R.drawable.downloadplaceholder).cacheInMemory().cacheOnDisc().showImageOnFail(R.drawable.loading).build();

    ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(getApplicationContext()).
            defaultDisplayImageOptions(displayimageOptions).memoryCache(new WeakMemoryCache()).discCache(new UnlimitedDiscCache(cacheDir)).build();

    if (ImageLoader.getInstance().isInited()) {
        ImageLoader.getInstance().destroy();
    }
    ImageLoader.getInstance().init(config);

    imageLoadingListener = new ImageLoadingListener() {
        @Override
        public void onLoadingStarted(String s, View view) {

        }

        @Override
        public void onLoadingFailed(String s, View view, FailReason failReason) {
            ImageView imageView = (ImageView) view;
            imageView.setImageResource(R.drawable.android);
            Log.i("Failed to Load " + s, failReason.toString());
        }

        @Override
        public void onLoadingComplete(String s, View view, Bitmap bitmap) {

        }

        @Override
        public void onLoadingCancelled(String s, View view) {

        }
    };

//Imageloader usage
ImageView imageView = new ImageView(getApplicationContext());
    if (orientation == 1) {
        imageView.setLayoutParams(new LinearLayout.LayoutParams(width / 6, width / 6));
    } else {
        imageView.setLayoutParams(new LinearLayout.LayoutParams(height / 6, height / 6));
    }
    imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
    imageLoader.displayImage(SERVER_HOSTNAME + "demos" + demo.getPathRoot() + demo.getRootName() + ".png", imageView, imageLoadingListener);

This can lazy load the images, fit them correctly to the size of the imageView showing a placeholder image while it loads, and showing a default icon if loading fails and caching the resources.

-- I should also add that this current config keeps the image aspect ratio, hence applicable to your original question

How to make for loops in Java increase by increments other than 1

for(j = 0; j<=90; j++){}

j++ means j=j+1, j value already 0 now we are adding 1 so now the sum value of j+1 became 1, finally we are overriding the j value(0) with the sum value(1) so here we are overriding the j value by j+1. So each iteration j value will be incremented by 1.

for(j = 0; j<=90; j+3){}

Here j+3 means j value already 0 now we are adding 3 so now the sum value of j+3 became 3 but we are not overriding the existing j value. So that JVM asking the programmer, you are calculating the new value but where you are assigning that value to a variable(i.e j). That's why we are getting the compile-time error " invalid AssignmentOperator ".

If we want to increment j value by 3 then we can use any one of the following way.

 for (int j=0; j<=90; j+=3)  --> here each iteration j value will be incremented by 3.
 for (int j=0; j<=90; j=j+3) --> here each iteration j value will be incremented by 3.  

git rebase: "error: cannot stat 'file': Permission denied"

I've only ever seen this error on Windows and what it seems to mean is that something blocked git from modifying a file at the moment when it tried to a apply a patch.

Windows tends to give processes exclusive access to files when it shouldn't really be necessary, in the past virus checkers have been one source of suspicion but I've never proved this conclusively.

Probably the easiest thing to do is to abort and try again, hoping that it doesn't happen the next time.

git rebase --abort

You can attempt to use git apply and knowledge of what commit git was actually trying to do before doing a git rebase --continue but in all honesty I wouldn't recommend this. Most of the times I've seen this tried there's been a better than evens chance that something gets accidentally missed or messed up.

How do I set the default schema for a user in MySQL

If your user has a local folder e.g. Linux, in your users home folder you could create a .my.cnf file and provide the credentials to access the server there. for example:-

[client]
host=localhost
user=yourusername
password=yourpassword or exclude to force entry
database=mygotodb

Mysql would then open this file for each user account read the credentials and open the selected database.

Not sure on Windows, I upgraded from Windows because I needed the whole house not just the windows (aka Linux) a while back.

Javascript Regular Expression Remove Spaces

In production and works across line breaks

This is used in several apps to clean user-generated content removing extra spacing/returns etc but retains the meaning of spaces.

text.replace(/[\n\r\s\t]+/g, ' ')

Change the bullet color of list

You have to use image

.listStyle {
    list-style: none;
    background: url(bullet.jpg) no-repeat left center;
    padding-left: 40px;
}

How to get the title of HTML page with JavaScript?

Use document.title:

_x000D_
_x000D_
console.log(document.title)
_x000D_
<title>Title test</title>
_x000D_
_x000D_
_x000D_

MDN Web Docs

How do you set, clear, and toggle a single bit?

Expanding on the bitset answer:

#include <iostream>
#include <bitset>
#include <string>

using namespace std;
int main() {
  bitset<8> byte(std::string("10010011");

  // Set Bit
  byte.set(3); // 10010111

  // Clear Bit
  byte.reset(2); // 10010101

  // Toggle Bit
  byte.flip(7); // 00010101

  cout << byte << endl;

  return 0;
}

How do check if a parameter is empty or null in Sql Server stored procedure in IF statement?

To check if variable is null or empty use this:

IF LEN(ISNULL(@var, '')) = 0
    -- Is empty or NULL
ELSE
    -- Is not empty and is not NULL

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

Alternate way.

If you don't want to add the PATH as the previous well written answers pointed out,

but you want to execute pip as your command then you can do that with py -m as prefix.

Given that you have to do it again and again.

eg.

py -m <command>

as in

py -m pip install --upgrade pip setuptools

Also make sure to have pip and py installed

enter image description here

C99 stdint.h header and MS Visual Studio

Boost contains cstdint.hpp header file with the types you are looking for: http://www.boost.org/doc/libs/1_36_0/boost/cstdint.hpp

Executing <script> elements inserted with .innerHTML

Made this new helper function in TypeScript, maybe someone will appreciate it. If you remove type declaration from script parameter it will just be plain JS.

_x000D_
_x000D_
const evalPageScripts = () => {
  const scripts = document.querySelectorAll('script');

  scripts.forEach((script: HTMLScriptElement) => {
    const newScript = document.createElement('script');
    newScript.type = 'text/javascript';
    newScript.src = script.src;

    if (script.parentNode) {
      script.parentNode.removeChild(script);
    }

    return document.body.appendChild(newScript);
  })
};

export default evalPageScripts;
_x000D_
_x000D_
_x000D_

Determine the size of an InputStream

I would read into a ByteArrayOutputStream and then call toByteArray() to get the resultant byte array. You don't need to define the size in advance (although it's possibly an optimisation if you know it. In many cases you won't)

Comparing two input values in a form validation with AngularJS

One way to achieve this is with a custom directive. Here's an example using a custom directive (ng-match in this case):

<p>Email:<input type="email" name="email1" ng-model="emailReg">
Repeat Email:<input type="email" name="email2" ng-model="emailReg2" ng-match="emailReg"></p>

<span data-ng-show="myForm.emailReg2.$error.match">Emails have to match!</span>

NOTE: It's not generally recommended to use ng- as a prefix for a custom directive because it may conflict with an official AngularJS directive.

Update

It's also possible to get this functionality without using a custom directive:

HTML

<button ng-click="add()></button>
<span ng-show="IsMatch">Emails have to match!</span>

Controller

$scope.add = function() {
  if ($scope.emailReg != $scope.emailReg2) {
    $scope.IsMatch=true;
    return false;
  }
  $scope.IsMatch=false;
}

Changing color of Twitter bootstrap Nav-Pills

If you don't want to include any extra CSS you can just use the button color classes into the nav-link element, it will format the pill just the same as a regular button.

_x000D_
_x000D_
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">_x000D_
_x000D_
<script src="https://code.jquery.com/jquery-3.4.1.min.js" integrity="sha256-CSXorXvZcTkaix6Yvo6HppcZGetbYMGWSFlBw8HfCJo=" crossorigin="anonymous"></script>_x000D_
_x000D_
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script>_x000D_
_x000D_
<ul class="nav nav-pills p-3">_x000D_
    <li class="nav-item">_x000D_
        <a class="nav-link active" href="#">Normal</a>_x000D_
    </li>_x000D_
    <li class="nav-item">_x000D_
        <a class="nav-link active btn-primary" href="#">Primary</a>_x000D_
    </li>_x000D_
    <li class="nav-item">_x000D_
        <a class="nav-link active btn-secondary" href="#">Secondary</a>_x000D_
    </li>_x000D_
    <li class="nav-item">_x000D_
        <a class="nav-link active btn-success" href="#">Success</a>_x000D_
    </li>_x000D_
    <li class="nav-item">_x000D_
        <a class="nav-link active btn-warning" href="#">Warning</a>_x000D_
    </li>_x000D_
    <li class="nav-item">_x000D_
        <a class="nav-link active btn-danger" href="#">Danger</a>_x000D_
    </li>_x000D_
_x000D_
</ul>
_x000D_
_x000D_
_x000D_

Compiling LaTex bib source

You need to compile the bibtex file.

Suppose you have article.tex and article.bib. You need to run:

  • latex article.tex (this will generate a document with question marks in place of unknown references)
  • bibtex article (this will parse all the .bib files that were included in the article and generate metainformation regarding references)
  • latex article.tex (this will generate document with all the references in the correct places)
  • latex article.tex (just in case if adding references broke page numbering somewhere)

How can I initialize base class member variables in derived class constructor?

Leaving aside the fact that they are private, since a and b are members of A, they are meant to be initialized by A's constructors, not by some other class's constructors (derived or not).

Try:

class A
{
    int a, b;

protected: // or public:
    A(int a, int b): a(a), b(b) {}
};

class B : public A
{
    B() : A(0, 0) {}
};

Is it possible to write to the console in colour in .NET?

Yes, it is possible as follows. These colours can be used in a console application to view some errors in red, etc.

Console.BackgroundColor = ConsoleColor.Blue;
Console.ForegroundColor = ConsoleColor.White;//after this line every text will be white on blue background
Console.WriteLine("White on blue.");
Console.WriteLine("Another line.");
Console.ResetColor();//reset to the defoult colour

How to get an object's methods?

In modern browsers you can use Object.getOwnPropertyNames to get all properties (both enumerable and non-enumerable) on an object. For instance:

function Person ( age, name ) {
    this.age = age;
    this.name = name;
}

Person.prototype.greet = function () {
    return "My name is " + this.name;
};

Person.prototype.age = function () {
    this.age = this.age + 1;
};

// ["constructor", "greet", "age"]
Object.getOwnPropertyNames( Person.prototype );

Note that this only retrieves own-properties, so it will not return properties found elsewhere on the prototype chain. That, however, doesn't appear to be your request so I will assume this approach is sufficient.

If you would only like to see enumerable properties, you can instead use Object.keys. This would return the same collection, minus the non-enumerable constructor property.

How to check all versions of python installed on osx and centos

COMMAND: python --version && python3 --version

OUTPUT:

Python 2.7.10
Python 3.7.1

ALIAS COMMAND: pyver

OUTPUT:

Python 2.7.10
Python 3.7.1

You can make an alias like "pyver" in your .bashrc file or else using a text accelerator like AText maybe.

What is the difference between an interface and abstract class?

You can find clear difference between interface and abstract class.

Interface

  • Interface only contains abstract methods.
  • Force users to implement all methods when implements the interface.
  • Contains only final and static variables.
  • Declare using interface keyword.
  • All methods of an interface must be defined as public.
  • An interface can extend or a class can implement multiple other interfaces.

Abstract class

  • Abstract class contains abstract and non-abstract methods.

  • Does not force users to implement all methods when inherited the abstract class.

  • Contains all kinds of variables including primitive and non-primitive

  • Declare using abstract keyword.

  • Methods and members of an abstract class can be defined with any visibility.

  • A child class can only extend a single class (abstract or concrete).

Difference between JPanel, JFrame, JComponent, and JApplet

JFrame and JApplet are top level containers. If you wish to create a desktop application, you will use JFrame and if you plan to host your application in browser you will use JApplet.

JComponent is an abstract class for all Swing components and you can use it as the base class for your new component. JPanel is a simple usable component you can use for almost anything.

Since this is for a fun project, the simplest way for you is to work with JPanel and then host it inside JFrame or JApplet. Netbeans has a visual designer for Swing with simple examples.

java : non-static variable cannot be referenced from a static context Error

Java has two kind of Variables

a)
Class Level (Static) :
They are one per Class.Say you have Student Class and defined name as static variable.Now no matter how many student object you create all will have same name.

Object Level :
They belong to per Object.If name is non-static ,then all student can have different name.

b)
Class Level :
This variables are initialized on Class load.So even if no student object is created you can still access and use static name variable.

Object Level: They will get initialized when you create a new object ,say by new();

C)
Your Problem : Your class is Just loaded in JVM and you have called its main (static) method : Legally allowed.

Now from that you want to call an Object varibale : Where is the object ??

You have to create a Object and then only you can access Object level varibales.

How do I change the default application icon in Java?

Try This write after

initcomponents();

setIconImage(Toolkit.getDefaultToolkit().getImage(getClass().getResource("Your image address")));

Selecting between two dates within a DateTime field - SQL Server

select * 
from blah 
where DatetimeField between '22/02/2009 09:00:00.000' and '23/05/2009 10:30:00.000'

Depending on the country setting for the login, the month/day may need to be swapped around.

Android Studio : How to uninstall APK (or execute adb command) automatically before Run or Debug?

List the packages by:

adb shell su 0 pm list packages

Review which package you want to uninstall and copy the package name from there. For example:

com.android.calculator2

Lastly type in:

adb uninstall com.android.calculator2 

and you are done.

Laravel 5 call a model function in a blade view

I solve the problem. So simple. Syntax error.

  • App\Product
  • App\Service

enter image description here

But I also want to know how to pass a function with parameters to view....

How can I make git show a list of the files that are being tracked?

You might want colored output with this.

I use this one-liner for listing the tracked files and directories in the current directory of the current branch:

ls --group-directories-first --color=auto -d $(git ls-tree $(git branch | grep \* | cut -d " " -f2) --name-only)

You might want to add it as an alias:

alias gl='ls --group-directories-first --color=auto -d $(git ls-tree $(git branch | grep \* | cut -d " " -f2) --name-only)'

If you want to recursively list files:

'ls' --color=auto -d $(git ls-tree -rt $(git branch | grep \* | cut -d " " -f2) --name-only)

And an alias:

alias glr="'ls' --color=auto -d \$(git ls-tree -rt \$(git branch | grep \\* | cut -d \" \" -f2) --name-only)"

Numpy array dimensions

The shape method requires that a be a Numpy ndarray. But Numpy can also calculate the shape of iterables of pure python objects:

np.shape([[1,2],[1,2]])

How can I put strings in an array, split by new line?

That's my way:

$lines = preg_split('/[\r\n]+/', $db_text, NULL, PREG_SPLIT_NO_EMPTY);

This also will skip all empty lines too.

time delayed redirect?

 <script type="text/JavaScript">
      setTimeout("location.href = 'http://www.your_site.com';",1500);
 </script>

Python Dictionary Comprehension

Use dict() on a list of tuples, this solution will allow you to have arbitrary values in each list, so long as they are the same length

i_s = range(1, 11)
x_s = range(1, 11)
# x_s = range(11, 1, -1) # Also works
d = dict([(i_s[index], x_s[index], ) for index in range(len(i_s))])

Import Excel spreadsheet columns into SQL Server database

This may sound like the long way around, but you may want to look at using Excel to generate INSERT SQL code that you can past into Query Analyzer to create your table.

Works well if you cant use the wizards because the excel file isn't on the server

PHP expects T_PAAMAYIM_NEKUDOTAYIM?

This just happened to me in a foreach loop. I had inadvertently typed ($array as $key as $value) and PHP objected to the first as.

PHP how to get value from array if key is in a variable

As others stated, it's likely failing because the requested key doesn't exist in the array. I have a helper function here that takes the array, the suspected key, as well as a default return in the event the key does not exist.

    protected function _getArrayValue($array, $key, $default = null)
    {
        if (isset($array[$key])) return $array[$key];
        return $default;
    }

hope it helps.

java.lang.UnsupportedClassVersionError

The code was most likely compiled with a later JDK (without using cross-compilation options) and is being run on an earlier JRE. While upgrading the JRE is one solution, it would be better to use the cross-compilation options to ensure the code will run on whatever JRE is intended as the minimum version for the app.

Print execution time of a shell command

Don't forget that there is a difference between bash's builtin time (which should be called by default when you do time command) and /usr/bin/time (which should require you to call it by its full path).

The builtin time always prints to stderr, but /usr/bin/time will allow you to send time's output to a specific file, so you do not interfere with the executed command's stderr stream. Also, /usr/bin/time's format is configurable on the command line or by the environment variable TIME, whereas bash's builtin time format is only configured by the TIMEFORMAT environment variable.

$ time factor 1234567889234567891 # builtin
1234567889234567891: 142662263 8653780357

real    0m3.194s
user    0m1.596s
sys 0m0.004s
$ /usr/bin/time factor 1234567889234567891
1234567889234567891: 142662263 8653780357
1.54user 0.00system 0:02.69elapsed 57%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+215minor)pagefaults 0swaps
$ /usr/bin/time -o timed factor 1234567889234567891 # log to file `timed`
1234567889234567891: 142662263 8653780357
$ cat timed
1.56user 0.02system 0:02.49elapsed 63%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+217minor)pagefaults 0swaps

Difference between left join and right join in SQL Server

(INNER) JOIN: Returns records that have matching values in both tables.

LEFT (OUTER) JOIN: Return all records from the left table, and the matched records from the right table.

RIGHT (OUTER) JOIN: Return all records from the right table, and the matched records from the left table.

FULL (OUTER) JOIN: Return all records when there is a match in either left or right table

For example, lets suppose we have two table with following records:

Table A

id   firstname   lastname
___________________________
1     Ram         Thapa
2     sam         Koirala
3     abc         xyz
6    sruthy       abc

Table B

id2   place
_____________
1      Nepal
2      USA
3      Lumbini
5      Kathmandu

Inner Join

Note: It give the intersection of two table.

Inner Join

Syntax

SELECT column_name FROM table1 INNER JOIN table2 ON table1.column_name = table2.column_name;

Apply it in your sample table:

SELECT TableA.firstName,TableA.lastName,TableB.Place FROM TableA INNER JOIN TableB ON TableA.id = TableB.id2;

Result will be:

firstName       lastName       Place
_____________________________________
  Ram         Thapa             Nepal
  sam         Koirala            USA
  abc         xyz              Lumbini

Left Join

Note : will give all selected rows in TableA, plus any common selected rows in TableB.

Left join

SELECT column_name(s) FROM table1 LEFT JOIN table2 ON table1.column_name = table2.column_name;

Apply it in your sample table

SELECT TableA.firstName,TableA.lastName,TableB.Place FROM TableA LEFT JOIN TableB ON TableA.id = TableB.id2;

Result will be:

firstName   lastName    Place
______________________________
 Ram         Thapa      Nepal
 sam         Koirala    USA
 abc         xyz        Lumbini
sruthy       abc        Null

Right Join

Note:will give all selected rows in TableB, plus any common selected rows in TableA.

Right Join

Syntax:

SELECT column_name(s) FROM table1 RIGHT JOIN table2 ON table1.column_name = table2.column_name;

Apply it in your samole table:

SELECT TableA.firstName,TableA.lastName,TableB.Place FROM TableA RIGHT JOIN TableB ON TableA.id = TableB.id2;

Result will bw:

firstName   lastName     Place
______________________________
Ram         Thapa         Nepal
sam         Koirala       USA
abc         xyz           Lumbini
Null        Null          Kathmandu

Full Join

Note : It is same as union operation, it will return all selected values from both tables.

Full join

Syntax:

SELECT column_name(s) FROM table1 FULL OUTER JOIN table2 ON table1.column_name = table2.column_name;

Apply it in your samp[le table:

SELECT TableA.firstName,TableA.lastName,TableB.Place FROM TableA FULL JOIN TableB ON TableA.id = TableB.id2;

Result will be:

firstName   lastName    Place
______________________________
 Ram         Thapa      Nepal
 sam         Koirala    USA
 abc         xyz        Lumbini
sruthy       abc        Null
 Null         Null      Kathmandu

Some facts

For INNER joins the order doesn't matter

For (LEFT, RIGHT or FULL) OUTER joins,the order matter

Find More at w3schools

JavaScript - Get minutes between two dates

For those that like to work with small numbers

const today = new Date();
const endDate = new Date(startDate.setDate(startDate.getDate() + 7));
const days = parseInt((endDate - today) / (1000 * 60 * 60 * 24));
const hours = parseInt(Math.abs(endDate - today) / (1000 * 60 * 60) % 24);
const minutes = parseInt(Math.abs(endDate.getTime() - today.getTime()) / (1000 * 60) % 60);
const seconds = parseInt(Math.abs(endDate.getTime() - today.getTime()) / (1000) % 60); 

Is there a mechanism to loop x times in ES6 (ECMAScript 6) without mutable variables?

const times = 4;
new Array(times).fill().map(() => console.log('test'));

This snippet will console.log test 4 times.

AngularJS event on window innerWidth size change

If Khanh TO's solution caused UI issues for you (like it did for me) try using $timeout to not update the attribute until it has been unchanged for 500ms.

var oldWidth = window.innerWidth;
$(window).on('resize.doResize', function () {
    var newWidth = window.innerWidth,
        updateStuffTimer;

    if (newWidth !== oldWidth) {
        $timeout.cancel(updateStuffTimer);
    }

    updateStuffTimer = $timeout(function() {
         updateStuff(newWidth); // Update the attribute based on window.innerWidth
    }, 500);
});

$scope.$on('$destroy',function (){
    $(window).off('resize.doResize'); // remove the handler added earlier
});

Reference: https://gist.github.com/tommaitland/7579618

git clone error: RPC failed; curl 56 OpenSSL SSL_read: SSL_ERROR_SYSCALL, errno 10054

git config --global http.postBuffer 524288000

Work in my case - AWS code commit

How can I change the thickness of my <hr> tag

I suggest to use construction like

<style>
  .hr { height:0; border-top:1px solid _anycolor_; }
  .hr hr { display:none }
</style>

<div class="hr"><hr /></div>

Why maven? What are the benefits?

Figuring out package dependencies is really not that hard. You rarely do it anyway. Probably once during project setup and few more during upgrades. With maven you'll end up fixing mismatched dependencies, badly written poms, and doing package exclusions anyway.

Not that hard... for toy projects. But the projects I work on have many, really many, of them, and I'm very glad to get them transitively, to have a standardized naming scheme for them. Managing all this manually by hand would be a nightmare.

And yes, sometimes you have to work on the convergence of dependencies. But think about it twice, this is not inherent to Maven, this is inherent to any system using dependencies (and I am talking about Java dependencies in general here).

So with Ant, you have to do the same work except that you have to do everything manually: grabbing some version of project A and its dependencies, grabbing some version of project B and its dependencies, figuring out yourself what exact versions they use, checking that they don't overlap, checking that they are not incompatible, etc. Welcome to hell.

On the other hand, Maven supports dependency management and will retrieve them transitively for me and gives me the tooling I need to manage the complexity inherent to dependency management: I can analyze a dependency tree, control the versions used in transitive dependencies, exclude some of them if required, control the converge across modules, etc. There is no magic. But at least you have support.

And don't forget that dependency management is only a small part of what Maven offers, there is much more (not even mentioning the other tools that integrates nicely with Maven, e.g. Sonar).

Slow FIX-COMPILE-DEPLOY-DEBUG cycle, which kills productivity. This is my main gripe. You make a change, the you have to wait for maven build to kick in and wait for it to deploy. No hot deployment whatsoever.

First, why do you use Maven like this? I don't. I use my IDE to write tests, code until they pass, refactor, deploy, hot deploy and run a local Maven build when I'm done, before to commit, to make sure I will not break the continuous build.

Second, I'm not sure using Ant would make things much better. And to my experience, modular Maven builds using binary dependencies gives me faster build time than typical monolithic Ant builds. Anyway, have a look at Maven Shell for a ready to (re)use Maven environment (which is awesome by the way).

So at end, and I'm sorry to say so, it's not really Maven that is killing your productivity, it's you misusing your tools. And if you're not happy with it, well, what can I say, don't use it. Personally, I'm using Maven since 2003 and I never looked back.

What is Dispatcher Servlet in Spring?

We can say like DispatcherServlet taking care of everything in Spring MVC.

At web container start up:

  1. DispatcherServlet will be loaded and initialized by calling init() method
  2. init() of DispatcherServlet will try to identify the Spring Configuration Document with naming conventions like "servlet_name-servlet.xml" then all beans can be identified.

Example:

public class DispatcherServlet extends HttpServlet {

    ApplicationContext ctx = null;

    public void init(ServletConfig cfg){
        // 1. try to get the spring configuration document with default naming conventions
        String xml = "servlet_name" + "-servlet.xml";

        //if it was found then creates the ApplicationContext object
        ctx = new XmlWebApplicationContext(xml);
    }
    ...
}

So, in generally DispatcherServlet capture request URI and hand over to HandlerMapping. HandlerMapping search mapping bean with method of controller, where controller returning logical name(view). Then this logical name is send to DispatcherServlet by HandlerMapping. Then DispatcherServlet tell ViewResolver to give full location of view by appending prefix and suffix, then DispatcherServlet give view to the client.

ScrollIntoView() causing the whole page to move

jQuery plugin scrollintoview() increases usability

Instead of default DOM implementation you can use a plugin that animates movement and doesn't have any unwanted effects. Here's the simplest way of using it with defaults:

$("yourTargetLiSelector").scrollintoview();

Anyway head over to this blog post where you can read all the details and will eventually get you to GitHub source codeof the plugin.

This plugin automatically searches for the closest scrollable ancestor element and scrolls it so that selected element is inside its visible view port. If the element is already in the view port it doesn't do anything of course.

Inserting NOW() into Database with CodeIgniter's Active Record

aspirinemaga, just replace:

$this->db->set('time', 'NOW()', FALSE);
$this->db->insert('mytable', $data);

for it:

$this->db->set('time', 'NOW() + INTERVAL 1 DAY', FALSE);
$this->db->insert('mytable', $data);

How to change Java version used by TOMCAT?

test open the termenal or cmd. go to the [tomcat-home]\bin directory. ex: c:\tomcat8\bin write the following command: Tomcat8W //ES//Tomcat8 will open dialog, select the java tap(top tap). change the Java virtual Machine value.

Shell script "for" loop syntax

These all do {1..8} and should all be POSIX. They also will not break if you put a conditional continue in the loop. The canonical way:

f=
while [ $((f+=1)) -le 8 ]
do
  echo $f
done

Another way:

g=
while
  g=${g}1
  [ ${#g} -le 8 ]
do
  echo ${#g}
done

and another:

set --
while
  set $* .
  [ ${#} -le 8 ]
do
  echo ${#}
done

Accessing dictionary value by index in python

While you can do

value = d.values()[index]

It should be faster to do

value = next( v for i, v in enumerate(d.itervalues()) if i == index )

edit: I just timed it using a dict of len 100,000,000 checking for the index at the very end, and the 1st/values() version took 169 seconds whereas the 2nd/next() version took 32 seconds.

Also, note that this assumes that your index is not negative

MySQL - How to increase varchar size of an existing column in a database without breaking existing data?

I'd like explain the different alter table syntaxes - See the MySQL documentation

For adding/removing defaults on a column:

ALTER TABLE table_name
ALTER COLUMN col_name {SET DEFAULT literal | DROP DEFAULT}

For renaming a column, changing it's data type and optionally changing the column order:

ALTER TABLE table_name
CHANGE [COLUMN] old_col_name new_col_name column_definition
[FIRST|AFTER col_name]

For changing a column's data type and optionally changing the column order:

ALTER TABLE table_name
MODIFY [COLUMN] col_name column_definition
[FIRST | AFTER col_name]

How to center the elements in ConstraintLayout

Update:

Chain

You can now use the chain feature in packed mode as describe in Eugene's answer.


Guideline

You can use a horizontal guideline at 50% position and add bottom and top (8dp) constraints to edittext and button:

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="16dp"
    android:paddingRight="16dp">

    <android.support.design.widget.TextInputLayout
        android:id="@+id/client_id_input_layout"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        app:layout_constraintBottom_toTopOf="@+id/guideline"
        android:layout_marginRight="8dp"
        app:layout_constraintRight_toRightOf="parent"
        android:layout_marginLeft="8dp"
        app:layout_constraintLeft_toLeftOf="parent">

        <android.support.design.widget.TextInputEditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="@string/login_client_id"
            android:inputType="textEmailAddress"/>

    </android.support.design.widget.TextInputLayout>

    <android.support.v7.widget.AppCompatButton
        android:id="@+id/authenticate"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="@string/login_auth"
        app:layout_constraintTop_toTopOf="@+id/guideline"
        android:layout_marginTop="8dp"
        android:layout_marginRight="8dp"
        app:layout_constraintRight_toRightOf="parent"
        android:layout_marginLeft="8dp"
        app:layout_constraintLeft_toLeftOf="parent"/>

    <android.support.constraint.Guideline
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/guideline"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.5"/>

</android.support.constraint.ConstraintLayout>

Layout Editor

how to convert java string to Date object

The concise version:

String dateStr = "06/27/2007";
DateFormat formatter = new SimpleDateFormat("MM/dd/yyyy");
Date startDate = (Date)formatter.parse(dateStr);  

Add a try/catch block for a ParseException to ensure the format is a valid date.

Git workflow and rebase vs merge questions

DO NOT use git push origin --mirror UNDER ALMOST ANY CIRCUMSTANCE.

It does not ask if you're sure you want to do this, and you'd better be sure, because it will erase all of your remote branches that are not on your local box.

http://twitter.com/dysinger/status/1273652486

VBA vlookup reference in different sheet

The answer your question: the correct way to refer to a different sheet is by appropriately qualifying each Range you use. Please read this explanation and its conclusion, which I guess will give essential information.

The error you are getting is likely due to the sought-for value Sheet2!D2 not being found in the searched range Sheet1!A1:A65536. This may stem from two cases:

  1. The value is actually not present (pointed out by chris nielsen).

  2. You are searching the wrong Range. If the ActiveSheet is Sheet1, then using Range("D2") without qualifying it will be searching for Sheet1!D2, and it will throw the same error even if the sought-for value is present in the correct Range. Code accounting for this (and items below) follows:

    Sub srch()
        Dim ws1 As Worksheet, ws2 As Worksheet
        Dim srchres As Variant
    
        Set ws1 = Worksheets("Sheet1")
        Set ws2 = Worksheets("Sheet2")
    
        On Error Resume Next
        srchres = Application.WorksheetFunction.VLookup(ws2.Range("D2"), ws1.Range("A1:C65536"), 1, False)
        On Error GoTo 0
        If (IsEmpty(srchres)) Then
          ws2.Range("E2").Formula = CVErr(xlErrNA) ' Use whatever you want
        Else
          ws2.Range("E2").Value = srchres
        End If
    End Sub
    

I will point out a few additional notable points:

  1. Catching the error as done by chris nielsen is a good practice, probably mandatory if using Application.WorksheetFunction.VLookup (although it will not suitably handle case 2 above).

  2. This catching is actually performed by the function VLOOKUP as entered in a cell (and, if the sought-for value is not found, the result of the error is presented as #N/A in the result). That is why the first soluton by L42 does not need any extra error handling (it is taken care by =VLOOKUP...).

  3. Using =VLOOKUP... is fundamentally different from Application.WorksheetFunction.VLookup: the first leaves a formula, whose result may change if the cells referenced change; the second writes a fixed value.

  4. Both solutions by L42 qualify Ranges suitably.

  5. You are searching the first column of the range, and returning the value in that same column. Other functions are available for that (although yours works fine).

/bin/sh: pushd: not found

sudo dpkg-reconfigure dash 

Then select no.

HTML/CSS: how to put text both right and left aligned in a paragraph

Least amount of markup possible (you only need one span):

<p>This text is left. <span>This text is right.</span></p>

How you want to achieve the left/right styles is up to you, but I would recommend an external style on an ID or a class.

The full HTML:

<p class="split-para">This text is left. <span>This text is right.</span></p>

And the CSS:

.split-para      { display:block;margin:10px;}
.split-para span { display:block;float:right;width:50%;margin-left:10px;}

How to convert QString to int?

Use .toInt() for int .toFloat() for float and .toDouble() for double

toInt();

Python Serial: How to use the read or readline function to read more than 1 character at a time

I was reciving some date from my arduino uno (0-1023 numbers). Using code from 1337holiday, jwygralak67 and some tips from other sources:

import serial
import time

ser = serial.Serial(
    port='COM4',\
    baudrate=9600,\
    parity=serial.PARITY_NONE,\
    stopbits=serial.STOPBITS_ONE,\
    bytesize=serial.EIGHTBITS,\
        timeout=0)

print("connected to: " + ser.portstr)

#this will store the line
seq = []
count = 1

while True:
    for c in ser.read():
        seq.append(chr(c)) #convert from ANSII
        joined_seq = ''.join(str(v) for v in seq) #Make a string from array

        if chr(c) == '\n':
            print("Line " + str(count) + ': ' + joined_seq)
            seq = []
            count += 1
            break


ser.close()

How to install Python packages from the tar.gz file without using pip install

Install it by running

python setup.py install

Better yet, you can download from github. Install git via apt-get install git and then follow this steps:

git clone https://github.com/mwaskom/seaborn.git
cd seaborn
python setup.py install

How can I use ":" as an AWK field separator?

You can also use a regular expression as a field separator. The following will print "bar" by using a regular expression to set the number "10" as a separator.

echo "foo 10 bar" | awk -F'[0-9][0-9]' '{print $2}'

Android image caching

Late answer, but I figured I should add a link to my site because I have written a tutorial how to make an image cache for android: http://squarewolf.nl/2010/11/android-image-cache/ Update: the page has been taken offline as the source was outdated. I join @elenasys in her advice to use Ignition.

So to all the people who stumble upon this question and haven't found a solution: hope you enjoy! =D

Different names of JSON property during serialization and deserialization

You can use this variant:

import lombok.Getter;
import com.fasterxml.jackson.annotation.JsonGetter;
import com.fasterxml.jackson.annotation.JsonProperty;

//...

@JsonProperty(value = "rr") // for deserialization
@Getter(onMethod_ = {@JsonGetter(value = "r")}) // for serialization
private String rrrr;

with Lombok getter

Setting Oracle 11g Session Timeout

This is likely caused by your application's connection pool; not an Oracle DBMS issue. Most connection pools have a validate statement that can execute before giving you the connection. In oracle you would want "Select 1 from dual".

The reason it started occurring after you restarted the server is that the connection pool was probably added without a restart and you are just now experiencing the use of the connection pool for the first time. What is the modification dates on your resource files that deal with database connections?

Validate Query example:

 <Resource name="jdbc/EmployeeDB" auth="Container" 
            validationQuery="Select 1 from dual" type="javax.sql.DataSource" username="dbusername" password="dbpassword"
            driverClassName="org.hsql.jdbcDriver" url="jdbc:HypersonicSQL:database"
            maxActive="8" maxIdle="4"/>

EDIT: In the case of Grails, there are similar configuration options for the grails pool. Example for Grails 1.2 (see release notes for Grails 1.2)

dataSource {
    pooled = true
    dbCreate = "update"
    url = "jdbc:mysql://localhost/yourDB"
    driverClassName = "com.mysql.jdbc.Driver"
    username = "yourUser"
    password = "yourPassword"
    properties {
        maxActive = 50
        maxIdle = 25
        minIdle = 5
        initialSize = 5
        minEvictableIdleTimeMillis = 60000
        timeBetweenEvictionRunsMillis = 60000
        maxWait = 10000     
    }   
}

Expected response code 250 but got code "535", with message "535-5.7.8 Username and Password not accepted

This is my .env mail settings

MAIL_DRIVER=smtp
MAIL_HOST=smtp.googlemail.com
MAIL_PORT=587
[email protected]
MAIL_PASSWORD=hello27
MAIL_ENCRYPTION=tls

i was getting thesame error as stated in the question but by using

php artisan config:cache

Everything worked fine

Javascript sleep/delay/wait function

You could use the following code, it does a recursive call into the function in order to properly wait for the desired time.

function exportar(page,miliseconds,totalpages)
{
    if (page <= totalpages)
    {
        nextpage = page + 1;
        console.log('fnExcelReport('+ page +'); nextpage = '+ nextpage + '; miliseconds = '+ miliseconds + '; totalpages = '+ totalpages );
        fnExcelReport(page);
        setTimeout(function(){
            exportar(nextpage,miliseconds,totalpages);
        },miliseconds);
    };
}

How to change the icon of .bat file programmatically?

One of the way you can achieve this is:

  1. Create an executable Jar file
  2. Create a batch file to run the above jar and launch the desktop java application.
  3. Use Batch2Exe converter and covert to batch file to Exe.
  4. During above conversion, you can change the icon to that of your choice.(must of valid .ico file)
  5. Place the short cut for the above exe on desktop.

Now your java program can be opened in a fancy way just like any other MSWindows apps.! :)

Use sudo with password as parameter

# Make sure only root can run our script
if [ "$(id -u)" != "0" ]; then
   echo "This script must be run as root" 1>&2
   exit 1
fi

How do I run a batch file from my Java Application?

This code will execute two commands.bat that exist in the path C:/folders/folder.

Runtime.getRuntime().exec("cd C:/folders/folder & call commands.bat");

How to pass data from 2nd activity to 1st activity when pressed back? - android

Take This as an alternate to startActivityforResult.But keep in mind that for such cases this approach can be expensive in terms of performance but in some cases you might need to use.

In Activity2,

@Override
public void onBackPressed() {
String data = mEditText.getText();
SharedPreferences sp = getSharedPreferences("LoginInfos", 0);
Editor editor = sp.edit();
editor.putString("email",data);
editor.commit();
}

In Activity1,

 @Override
public void onResume() {
SharedPreferences sp = getSharedPreferences("LoginInfos", 0);
String  dataFromOtherAct= sp.getString("email", "no email");
} 

Navigation bar show/hide

To hide Navigation bar :

[self.navigationController setNavigationBarHidden:YES animated:YES];

To show Navigation bar :

[self.navigationController setNavigationBarHidden:NO animated:YES];

Search and replace part of string in database

I was just faced with a similar problem. I exported the contents of the db into one sql file and used TextEdit to find and replace everything I needed. Simplicity ftw!

pytest cannot import module while python can

In my case I am working in a container and unfortuantely pytest has the tendency to use python2.7 rather than my python3 interpreter of choice.

In my case this worked:

python3 -m pytest

My folder structure

/
app/
-module1.py
-module2.py
-tests/
--test_module1.py
--test_module2.py
requirements.txt
README.md

Having the output of a console application in Visual Studio instead of the console

A simple solution that works for me, to work with console ability(ReadKey, String with Format and arg etc) and to see and save the output:

I write TextWriter that write to Console and to Trace and replace the Console.Out with it.

if you use Dialog -> Debugging -> Check the "Redirect All Output Window Text to the Immediate Window" you get it in the Immediate Window and pretty clean.

my code: in start of my code:

Console.SetOut(new TextHelper());

and the class:

public class TextHelper : TextWriter
{
    TextWriter console;

    public TextHelper() {
        console = Console.Out;
    }

    public override Encoding Encoding => this.console.Encoding;

    public override void WriteLine(string format, params object[] arg)
    {
        string s = string.Format(format, arg);
        WriteLine(s);
    }

    public override void Write(object value)
    {
        console.Write(value);
        System.Diagnostics.Trace.Write(value);
    }

    public override void WriteLine(object value)
    {
        Write(value);
        Write("\n");
    }

    public override void WriteLine(string value)
    {
        console.WriteLine(value);
        System.Diagnostics.Trace.WriteLine(value);
    }
}

Note: I override just what I needed so if you write other types you should override more

How to call function on child component on parent events

The below example is self explainatory. where refs and events can be used to call function from and to parent and child.

// PARENT
<template>
  <parent>
    <child
      @onChange="childCallBack"
      ref="childRef"
      :data="moduleData"
    />
    <button @click="callChild">Call Method in child</button>
  </parent>
</template>

<script>
export default {
  methods: {
    callChild() {
      this.$refs.childRef.childMethod('Hi from parent');
    },
    childCallBack(message) {
      console.log('message from child', message);
    }
  }
};
</script>

// CHILD
<template>
  <child>
    <button @click="callParent">Call Parent</button>
  </child>
</template>

<script>
export default {
  methods: {
    callParent() {
      this.$emit('onChange', 'hi from child');
    },
    childMethod(message) {
      console.log('message from parent', message);
    }
  }
}
</script>

How to listen for a WebView finishing loading a URL?

@ian this is not 100% accurate. If you have several iframes in a page you will have multiple onPageFinished (and onPageStarted). And if you have several redirects it may also fail. This approach solves (almost) all the problems:

boolean loadingFinished = true;
boolean redirect = false;

mWebView.setWebViewClient(new WebViewClient() {

    @Override
    public boolean shouldOverrideUrlLoading(WebView view, String urlNewString) {
        if (!loadingFinished) {
            redirect = true;
        }

        loadingFinished = false;
        webView.loadUrl(urlNewString);
        return true;
    }

    @Override
    public void onPageStarted(WebView view, String url) {
        loadingFinished = false;
        //SHOW LOADING IF IT ISNT ALREADY VISIBLE  
    }

    @Override
    public void onPageFinished(WebView view, String url) {
        if (!redirect) {
           loadingFinished = true;
            //HIDE LOADING IT HAS FINISHED
        } else {
            redirect = false; 
        }
    }
});

UPDATE:

According to the documentation: onPageStarted will NOT be called when the contents of an embedded frame changes, i.e. clicking a link whose target is an iframe.

I found a specific case like that on Twitter where only a pageFinished was called and messed the logic a bit. To solve that I added a scheduled task to remove loading after X seconds. This is not needed in all the other cases.

UPDATE 2:

Now with current Android WebView implementation:

boolean loadingFinished = true;
boolean redirect = false;

    mWebView.setWebViewClient(new WebViewClient() {

        @Override
        public boolean shouldOverrideUrlLoading(
                WebView view, WebResourceRequest request) {
            if (!loadingFinished) {
               redirect = true;
            }

            loadingFinished = false;
            webView.loadUrl(request.getUrl().toString());
            return true;
        }

        @Override
        public void onPageStarted(
                WebView view, String url, Bitmap favicon) {
            super.onPageStarted(view, url, favicon);
            loadingFinished = false;
            //SHOW LOADING IF IT ISNT ALREADY VISIBLE  
        }

        @Override
        public void onPageFinished(WebView view, String url) {
            if (!redirect) {
               loadingFinished = true;
                //HIDE LOADING IT HAS FINISHED
            } else {
                redirect = false; 
            }
        }
    });

How to list the tables in a SQLite database file that was opened with ATTACH?

I use this query to get it:

SELECT name FROM sqlite_master WHERE type='table'

And to use in iOS:

NSString *aStrQuery=[NSString stringWithFormat:@"SELECT name FROM sqlite_master WHERE type='table'"];

What's the best way to override a user agent CSS stylesheet rule that gives unordered-lists a 1em margin?

Everything you write in your own stylesheet is overwriting the user agent styles - that's the point of writing your own stylesheet.

Resolve absolute path from relative path and/or file name

You can just concatenate them.

SET ABS_PATH=%~dp0 
SET REL_PATH=..\SomeFile.txt
SET COMBINED_PATH=%ABS_PATH%%REL_PATH%

it looks odd with \..\ in the middle of your path but it works. No need to do anything crazy :)

Why cannot change checkbox color whatever I do?

you cant change the background of checkbox but some how you can do a trick try this :)

_x000D_
_x000D_
.divBox {_x000D_
    width: 20px;_x000D_
    height: 20px;_x000D_
    background: #ddd;_x000D_
    margin: 20px 90px;_x000D_
    position: relative;_x000D_
    -webkit-box-shadow: 0px 1px 3px rgba(0,0,0,0.5);_x000D_
    -moz-box-shadow: 0px 1px 3px rgba(0,0,0,0.5);_x000D_
    box-shadow: 0px 1px 3px rgba(0,0,0,0.5);_x000D_
}_x000D_
_x000D_
.divBox label {_x000D_
    display: block;_x000D_
    width: 20px;_x000D_
    height: 20px;_x000D_
    -webkit-transition: all .5s ease;_x000D_
    -moz-transition: all .5s ease;_x000D_
    -o-transition: all .5s ease;_x000D_
    -ms-transition: all .5s ease;_x000D_
    transition: all .5s ease;_x000D_
    cursor: pointer;_x000D_
    position: absolute;_x000D_
    top: 1px;_x000D_
    z-index: 1;_x000D_
    /* _x000D_
    use this background transparent to check the value of checkbox _x000D_
    background: transparent;_x000D_
    */_x000D_
    background: Black;_x000D_
    -webkit-box-shadow:inset 0px 1px 3px rgba(0,0,0,0.5);_x000D_
    -moz-box-shadow:inset 0px 1px 3px rgba(0,0,0,0.5);_x000D_
    box-shadow:inset 0px 1px 3px rgba(0,0,0,0.5);_x000D_
}_x000D_
_x000D_
.divBox input[type=checkbox]:checked + label {_x000D_
    background: green;_x000D_
}
_x000D_
<div class="divBox">_x000D_
    <input type="checkbox" value="1" id="checkboxFourInput"name="" />_x000D_
    <label for="checkboxFourInput"></label>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Default value of 'boolean' and 'Boolean' in Java

class BooleanTester
{
    boolean primitive;
    Boolean object;

    public static void main(String[] args) {
        BooleanTester booleanTester = new BooleanTester();
        System.out.println("primitive: " + booleanTester.getPrimitive());
        System.out.println("object: " + booleanTester.getObject());
}

    public boolean getPrimitive() {
        return primitive;
    }

    public Boolean getObject() {
        return object;
    }
}

output:

primitive: false
object: null

This seems obvious but I had a situation where Jackson, while serializing an object to JSON, was throwing an NPE after calling a getter, just like this one, that returns a primitive boolean which was not assigned. This led me to believe that Jackson was receiving a null and trying to call a method on it, hence the NPE. I was wrong.

Moral of the story is that when Java allocates memory for a primitive, that memory has a value even if not initialized, which Java equates to false for a boolean. By contrast, when allocating memory for an uninitialized complex object like a Boolean, it allocates only space for a reference to that object, not the object itself - there is no object in memory to refer to - so resolving that reference results in null.

I think that strictly speaking, "defaults to false" is a little off the mark. I think Java does not allocate the memory and assign it a value of false until it is explicitly set; I think Java allocates the memory and whatever value that memory happens to have is the same as the value of 'false'. But for practical purpose they are the same thing.

How do I calculate the MD5 checksum of a file in Python?

In Python 3.8+ you can do

import hashlib

with open("your_filename.png", "rb") as f:
    file_hash = hashlib.md5()
    while chunk := f.read(8192):
        file_hash.update(chunk)

print(file_hash.digest())
print(file_hash.hexdigest())  # to get a printable str instead of bytes

On Python 3.7 and below:

with open("your_filename.png", "rb") as f:
    file_hash = hashlib.md5()
    chunk = f.read(8192)
    while chunk:
        file_hash.update(chunk)
        chunk = f.read(8192)

print(file_hash.hexdigest())

This reads the file 8192 (or 2¹³) bytes at a time instead of all at once with f.read() to use less memory.


Consider using hashlib.blake2b instead of md5 (just replace md5 with blake2b in the above snippets). It's cryptographically secure and faster than MD5.

Delete duplicate records from a SQL table without a primary key

select distinct * into newtablename from oldtablename

Now, the newtablename will have no duplicate records.

Simply change the table name(newtablename) by pressing F2 in object explorer in sql server.

Putting images with options in a dropdown list

You can't do that in plain HTML, but you can do it with jQuery:

JavaScript Image Dropdown

Are you tired with your old fashion dropdown? Try this new one. Image combo box. You can add an icon with each option. It works with your existing "select" element or you can create by JSON object.

Get attribute name value of <input>

Use the attr method of jQuery like this:

alert($('input').attr('name'));

Note that you can also use attr to set the attribute values by specifying second argument:

$('input').attr('name', 'new_name')

Get current time as formatted string in Go?

Use the time.Now() and time.Format() functions (as time.LocalTime() doesn't exist anymore as of Go 1.0.3)

t := time.Now()
fmt.Println(t.Format("20060102150405"))

Online demo (with date fixed in the past in the playground, never mind)

How can I use a C++ library from node.js?

Try shelljs to call c/c++ program or shared libraries by using node program from linux/unix . node-cmd an option in windows. Both packages basically enable us to call c/c++ program similar to the way we call from terminal/command line.

Eg in ubuntu:

const shell = require('shelljs');

shell.exec("command or script name");

In windows:

const cmd = require('node-cmd');
cmd.run('command here');

Note: shelljs and node-cmd are for running os commands, not specific to c/c++.

How do I remove all null and empty string values from an object?

According to Alexis King answer, here is a plain JavaScript version.

_x000D_
_x000D_
function cleanUp(obj) {_x000D_
    for (var attrKey in obj) {_x000D_
        var attrValue = obj[attrKey];_x000D_
        if (attrValue === null || attrValue === "") {_x000D_
            delete obj[attrKey];_x000D_
        } else if (Object.prototype.toString.call(attrValue) === "[object Object]") {_x000D_
            cleanUp(attrValue);_x000D_
        } else if (Array.isArray(attrValue)) {_x000D_
            attrValue.forEach(function (arrayValue) {_x000D_
                cleanUp(arrayValue);_x000D_
            });_x000D_
        }_x000D_
    }_x000D_
}
_x000D_
_x000D_
_x000D_

Pandas - Plotting a stacked Bar Chart

Are you getting errors, or just not sure where to start?

%pylab inline
import pandas as pd
import matplotlib.pyplot as plt

df2 = df.groupby(['Name', 'Abuse/NFF'])['Name'].count().unstack('Abuse/NFF').fillna(0)
df2[['abuse','nff']].plot(kind='bar', stacked=True)

stacked bar plot

How do I plot list of tuples in Python?

You could also use zip

import matplotlib.pyplot as plt

l = [(0, 6.0705199999997801e-08), (1, 2.1015700100300739e-08),
     (2, 7.6280656623374823e-09), (3, 5.7348209304555086e-09),
     (4, 3.6812203579604238e-09), (5, 4.1572516753310418e-09)]

x, y = zip(*l)

plt.plot(x, y)

How to import Maven dependency in Android Studio/IntelliJ?

Try itext. Add dependency to your build.gradle for latest as of this post

Note: special version for android, trailing "g":

dependencies {
    compile 'com.itextpdf:itextg:5.5.9'
}

Programmatically saving image to Django ImageField

class Pin(models.Model):
    """Pin Class"""
    image_link = models.CharField(max_length=255, null=True, blank=True)
    image = models.ImageField(upload_to='images/', blank=True)
    title = models.CharField(max_length=255, null=True, blank=True)
    source_name = models.CharField(max_length=255, null=True, blank=True)
    source_link = models.CharField(max_length=255, null=True, blank=True)
    description = models.TextField(null=True, blank=True)
    tags = models.ForeignKey(Tag, blank=True, null=True)

    def __unicode__(self):
        """Unicode class."""
        return unicode(self.image_link)

    def save(self, *args, **kwargs):
        """Store image locally if we have a URL"""
        if self.image_link and not self.image:
            result = urllib.urlretrieve(self.image_link)
            self.image.save(os.path.basename(self.image_link), File(open(result[0], 'r')))
            self.save()
            super(Pin, self).save()

Colors in JavaScript console

I create now the log-css.js https://codepen.io/luis7lobo9b/pen/QWyobwY

// log-css.js v1
const log = console.log.bind();
const css = function(item, color = '#fff', background = 'none', fontSize = '12px', fontWeight = 700, fontFamily) {
    return ['%c ' + item + ' ', 'color:' + color + ';background:' + background + ';font-size:' + fontSize + ';font-weight:' + fontWeight + (fontFamily ? ';font-family:' + fontFamily : '')];
};
// example
log(...css('Lorem ipsum dolor sit amet, consectetur adipisicing elit.', 'rebeccapurple', '#000', '14px'));

How to pass variable number of arguments to a PHP function

In a new Php 5.6, you can use ... operator instead of using func_get_args().

So, using this, you can get all the parameters you pass:

function manyVars(...$params) {
   var_dump($params);
}

What is the difference between Serialization and Marshaling?

My understanding of marshalling is different to the other answers.

Serialization:

To Produce or rehydrate a wire-format version of an object graph utilizing a convention.

Marshalling:

To Produce or rehydrate a wire-format version of an object graph by utilizing a mapping file, so that the results can be customized. The tool may start by adhering to a convention, but the important difference is the ability to customize results.

Contract First Development:

Marshalling is important within the context of contract first development.

  • Its possible to make changes to an internal object graph, while keeping the external interface stable over time. This way all of the service subscribers won't have to be modified for every trivial change.
  • Its possible to map the results across different languages. For example from the property name convention of one language ('property_name') to another ('propertyName').

How to detect if user select cancel InputBox VBA Excel

The solution above does not work in all InputBox-Cancel cases. Most notably, it does not work if you have to InputBox a Range.

For example, try the following InputBox for defining a custom range ('sRange', type:=8, requires Set + Application.InputBox) and you will get an error upon pressing Cancel:

Sub Cancel_Handler_WRONG()
Set sRange = Application.InputBox("Input custom range", _
    "Cancel-press test", Selection.Address, Type:=8)
If StrPtr(sRange) = 0 Then  'I also tried with sRange.address and vbNullString
    MsgBox ("Cancel pressed!")
    Exit Sub
End If
    MsgBox ("Your custom range is " & sRange.Address)
End Sub

The only thing that works, in this case, is an "On Error GoTo ErrorHandler" statement before the InputBox + ErrorHandler at the end:

Sub Cancel_Handler_OK()
On Error GoTo ErrorHandler
Set sRange = Application.InputBox("Input custom range", _
    "Cancel-press test", Selection.Address, Type:=8)
MsgBox ("Your custom range is " & sRange.Address)
Exit Sub
ErrorHandler:
    MsgBox ("Cancel pressed")
End Sub

So, the question is how to detect either an error or StrPtr()=0 with an If statement?

Can iterators be reset in Python?

I see many answers suggesting itertools.tee, but that's ignoring one crucial warning in the docs for it:

This itertool may require significant auxiliary storage (depending on how much temporary data needs to be stored). In general, if one iterator uses most or all of the data before another iterator starts, it is faster to use list() instead of tee().

Basically, tee is designed for those situation where two (or more) clones of one iterator, while "getting out of sync" with each other, don't do so by much -- rather, they say in the same "vicinity" (a few items behind or ahead of each other). Not suitable for the OP's problem of "redo from the start".

L = list(DictReader(...)) on the other hand is perfectly suitable, as long as the list of dicts can fit comfortably in memory. A new "iterator from the start" (very lightweight and low-overhead) can be made at any time with iter(L), and used in part or in whole without affecting new or existing ones; other access patterns are also easily available.

As several answers rightly remarked, in the specific case of csv you can also .seek(0) the underlying file object (a rather special case). I'm not sure that's documented and guaranteed, though it does currently work; it would probably be worth considering only for truly huge csv files, in which the list I recommmend as the general approach would have too large a memory footprint.

Finding a substring within a list in Python

This prints all elements that contain sub:

for s in filter (lambda x: sub in x, list): print (s)

How do I set session timeout of greater than 30 minutes

If you want to never expire a session use 0 or negative value -1.

<session-config>
    <session-timeout>0</session-timeout>
</session-config>

or mention 1440 it indicates 1440 minutes [24hours * 60 minutes]

<session-config>
  <session-timeout>1440</session-timeout><!-- 24hours -->
</session-config>

Session will be expire after 24hours.

PreparedStatement IN clause alternatives?

An analysis of the various options available, and the pros and cons of each is available here.

The suggested options are:

  • Prepare SELECT my_column FROM my_table WHERE search_column = ?, execute it for each value and UNION the results client-side. Requires only one prepared statement. Slow and painful.
  • Prepare SELECT my_column FROM my_table WHERE search_column IN (?,?,?) and execute it. Requires one prepared statement per size-of-IN-list. Fast and obvious.
  • Prepare SELECT my_column FROM my_table WHERE search_column = ? ; SELECT my_column FROM my_table WHERE search_column = ? ; ... and execute it. [Or use UNION ALL in place of those semicolons. --ed] Requires one prepared statement per size-of-IN-list. Stupidly slow, strictly worse than WHERE search_column IN (?,?,?), so I don't know why the blogger even suggested it.
  • Use a stored procedure to construct the result set.
  • Prepare N different size-of-IN-list queries; say, with 2, 10, and 50 values. To search for an IN-list with 6 different values, populate the size-10 query so that it looks like SELECT my_column FROM my_table WHERE search_column IN (1,2,3,4,5,6,6,6,6,6). Any decent server will optimize out the duplicate values before running the query.

None of these options are super great, though.

Duplicate questions have been answered in these places with equally sane alternatives, still none of them super great:

The Right Answer, if you are using JDBC4 and a server that supports x = ANY(y), is to use PreparedStatement.setArray as described here:

There doesn't seem to be any way to make setArray work with IN-lists, though.


Sometimes SQL statements are loaded at runtime (e.g., from a properties file) but require a variable number of parameters. In such cases, first define the query:

query=SELECT * FROM table t WHERE t.column IN (?)

Next, load the query. Then determine the number of parameters prior to running it. Once the parameter count is known, run:

sql = any( sql, count );

For example:

/**
 * Converts a SQL statement containing exactly one IN clause to an IN clause
 * using multiple comma-delimited parameters.
 *
 * @param sql The SQL statement string with one IN clause.
 * @param params The number of parameters the SQL statement requires.
 * @return The SQL statement with (?) replaced with multiple parameter
 * placeholders.
 */
public static String any(String sql, final int params) {
    // Create a comma-delimited list based on the number of parameters.
    final StringBuilder sb = new StringBuilder(
        String.join(", ", Collections.nCopies(possibleValue.size(), "?")));

    // For more than 1 parameter, replace the single parameter with
    // multiple parameter placeholders.
    if (sb.length() > 1) {
        sql = sql.replace("(?)", "(" + sb + ")");
    }

    // Return the modified comma-delimited list of parameters.
    return sql;
}

For certain databases where passing an array via the JDBC 4 specification is unsupported, this method can facilitate transforming the slow = ? into the faster IN (?) clause condition, which can then be expanded by calling the any method.

Command line to remove an environment variable from the OS level configuration

This has been covered quite a bit, but there's a crucial piece of information that's missing. Hopefully, I can help to clear up how this works and give some relief to weary travellers. :-)

Delete From Current Process

Obviously, everyone knows that you just do this to delete an environment variable from your current process:

set FOO=

Persistent Delete

There are two sets of environment variables, system-wide and user.

Delete User Environment Variable:

reg delete "HKCU\Environment" /v FOO /f

Delete System-Wide Environment Variable:

REG delete "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" /F /V FOO

Apply Value Without Rebooting

Here's the magic information that's missing! You're wondering why after you do this, when you launch a new command window, the environment variable is still there. The reason is because explorer.exe has not updated its environment. When one process launches another, the new process inherits the environment from the process that launched it.

There are two ways to fix this without rebooting. The most brute-force way is to kill your explorer.exe process and start it again. You can do that from Task Manager. I don't recommend this method, however.

The other way is by telling explorer.exe that the environment has changed and that it should reread it. This is done by broadcasting a Windows message (WM_SETTINGCHANGE). This can be accomplished with a simple PowerShell script. You could easily write one to do this, but I found one in Update Window Settings After Scripted Changes:

if (-not ("win32.nativemethods" -as [type])) {
    add-type -Namespace Win32 -Name NativeMethods -MemberDefinition @"
        [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        public static extern IntPtr SendMessageTimeout(
            IntPtr hWnd, uint Msg, UIntPtr wParam, string lParam,
            uint fuFlags, uint uTimeout, out UIntPtr lpdwResult);
        "@
}

$HWND_BROADCAST = [intptr]0xffff;
$WM_SETTINGCHANGE = 0x1a;
$result = [uintptr]::zero

[win32.nativemethods]::SendMessageTimeout($HWND_BROADCAST, $WM_SETTINGCHANGE,[uintptr]::Zero, "Environment", 2, 5000, [ref]$result);

Summary

So to delete a user environment variable named "FOO" and have the change reflected in processes you launch afterwards, do the following.

  1. Save the PowerShell script to a file (we'll call it updateenv.ps1).
  2. Do this from the command line: reg delete "HKCU\Environment" /v FOO /f
  3. Run updateenv.ps1.
  4. Close and reopen your command prompt, and you'll see that the environment variable is no longer defined.

Note, you'll probably have to update your PowerShell settings to allow you to run this script, but I'll leave that as a Google-fu exercise for you.

How To Raise Property Changed events on a Dependency Property?

I ran into a similar problem where I have a dependency property that I wanted the class to listen to change events to grab related data from a service.

public static readonly DependencyProperty CustomerProperty = 
    DependencyProperty.Register("Customer", typeof(Customer),
        typeof(CustomerDetailView),
        new PropertyMetadata(OnCustomerChangedCallBack));

public Customer Customer {
    get { return (Customer)GetValue(CustomerProperty); }
    set { SetValue(CustomerProperty, value); }
}

private static void OnCustomerChangedCallBack(
        DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
    CustomerDetailView c = sender as CustomerDetailView;
    if (c != null) {
        c.OnCustomerChanged();
    }
}

protected virtual void OnCustomerChanged() {
    // Grab related data.
    // Raises INotifyPropertyChanged.PropertyChanged
    OnPropertyChanged("Customer");
}

AngularJS open modal on button click

I am not sure,how you are opening popup or say model in your code. But you can try something like this..

<html ng-app="MyApp">
<head>

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js"></script>
<link rel="stylesheet" href="css/bootstrap.min.css" />

<script type="text/javascript">
    var myApp = angular.module("MyApp", []);
    myApp.controller('MyController', function ($scope) {
      $scope.open = function(){
        var modalInstance = $modal.open({
                        templateUrl: '/assets/yourOpupTemplatename.html',
                        backdrop:'static',
                        keyboard:false,
                        controller: function($scope, $modalInstance) {
                            $scope.cancel = function() {
                                $modalInstance.dismiss('cancel');
                            };
                            $scope.ok = function () {
                              $modalInstance.close();
                            };
                        }
                    });
      }
    });
</script>
</head>
<body ng-controller="MyController">

    <button class="btn btn-primary" ng-click="open()">Test Modal</button>

    <!-- Confirmation Dialog -->
    <div class="modal">
      <div class="modal-dialog">
        <div class="modal-content">
          <div class="modal-header">
            <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
            <h4 class="modal-title">Delete confirmation</h4>
          </div>
          <div class="modal-body">
            <p>Are you sure?</p>
          </div>
          <div class="modal-footer">
            <button type="button" class="btn btn-default" ng-click="cancel()">No</button>
            <button type="button" class="btn btn-primary" ng-click="ok()">Yes</button>
          </div>
        </div>
      </div>
    </div>
    <!-- End of Confirmation Dialog -->

 </body>
 </html>

filedialog, tkinter and opening files

Did you try adding the self prefix to the fileName and replacing the method above the Button ? With the self, it becomes visible between methods.

...

def load_file(self):
    self.fileName = filedialog.askopenfilename(filetypes = (("Template files", "*.tplate")
                                                     ,("HTML files", "*.html;*.htm")
                                                     ,("All files", "*.*") ))
...

General error: 1364 Field 'user_id' doesn't have a default value

In my case, the error was because I had not declared the field in my $fillable array in the model. Well, it seems to be something basic, but for us who started with laravel it could work.

Enabling CORS in Cloud Functions for Firebase

If there are people like me out there: If you want to call the cloud function from the same project as the cloud function it self, you can init the firebase sdk and use onCall method. It will handle everything for you:

exports.newRequest = functions.https.onCall((data, context) => {
    console.log(`This is the received data: ${data}.`);
    return data;
})

Call this function like this:

// Init the firebase SDK first    
const functions = firebase.functions();
const addMessage = functions.httpsCallable(`newRequest`);

Firebase docs: https://firebase.google.com/docs/functions/callable

If you can't init the SDK here is the essence from the other suggestions:

Last Key in Python Dictionary

In python 3.6 I got the value of last key from the following code

list(dict.keys())[-1]

How do I make CMake output into a 'bin' dir?

cat CMakeLists.txt
project (hello)
set(CMAKE_BINARY_DIR "/bin")
set(EXECUTABLE_OUTPUT_PATH ${CMAKE_BINARY_DIR})
add_executable (hello hello.c)

How to write dynamic variable in Ansible playbook

I would first suggest that you step back and look at organizing your plays to not require such complexity, but if you really really do, use the following:

   vars:
    myvariable: "{{[param1|default(''), param2|default(''), param3|default('')]|join(',')}}"

sqlite3.ProgrammingError: Incorrect number of bindings supplied. The current statement uses 1, and there are 74 supplied

You need to pass in a sequence, but you forgot the comma to make your parameters a tuple:

cursor.execute('INSERT INTO images VALUES(?)', (img,))

Without the comma, (img) is just a grouped expression, not a tuple, and thus the img string is treated as the input sequence. If that string is 74 characters long, then Python sees that as 74 separate bind values, each one character long.

>>> len(img)
74
>>> len((img,))
1

If you find it easier to read, you can also use a list literal:

cursor.execute('INSERT INTO images VALUES(?)', [img])

How do I copy the contents of one stream to another?

Easy and safe - make new stream from original source:

    MemoryStream source = new MemoryStream(byteArray);
    MemoryStream copy = new MemoryStream(byteArray);

No route matches "/users/sign_out" devise rails 3

Well, guys for me it was only remove the :method => :delete

<%= link_to('Sign out', destroy_user_session_path) %>

How do I create 7-Zip archives with .NET?

Install the NuGet package called SevenZipSharp.Interop

Then:

SevenZipBase.SetLibraryPath(@".\x86\7z.dll");
var compressor = new SevenZip.SevenZipCompressor();
var filesToCompress = Directory.GetFiles(@"D:\data\");
compressor.CompressFiles(@"C:\archive\abc.7z", filesToCompress);

Open Excel file for reading with VBA without display

In excel, hide the workbooks, and save them as hidden. When your app loads them they will not be shown.

Edit: upon re-reading, it became clear that these workbooks are not part of your application. Such a solution would be inappropriate for user workbooks.

How to convert column with dtype as object to string in Pandas Dataframe

Not answering the question directly, but it might help someone else.

I have a column called Volume, having both - (invalid/NaN) and numbers formatted with ,

df['Volume'] = df['Volume'].astype('str')
df['Volume'] = df['Volume'].str.replace(',', '')
df['Volume'] = pd.to_numeric(df['Volume'], errors='coerce')

Casting to string is required for it to apply to str.replace

pandas.Series.str.replace
pandas.to_numeric

Ruby class instance variable vs. class variable

As others said, class variables are shared between a given class and its subclasses. Class instance variables belong to exactly one class; its subclasses are separate.

Why does this behavior exist? Well, everything in Ruby is an object—even classes. That means that each class has an object of the class Class (or rather, a subclass of Class) corresponding to it. (When you say class Foo, you're really declaring a constant Foo and assigning a class object to it.) And every Ruby object can have instance variables, so class objects can have instance variables, too.

The trouble is, instance variables on class objects don't really behave the way you usually want class variables to behave. You usually want a class variable defined in a superclass to be shared with its subclasses, but that's not how instance variables work—the subclass has its own class object, and that class object has its own instance variables. So they introduced separate class variables with the behavior you're more likely to want.

In other words, class instance variables are sort of an accident of Ruby's design. You probably shouldn't use them unless you specifically know they're what you're looking for.

Increasing the maximum post size

I had a situation when variables went missing from POST and all of the above answers didn't help. It turned out that

max_input_vars=1000

was set by default and POST in question had more than that. This may be a problem.

CMake complains "The CXX compiler identification is unknown"

Your /home/gnu/bin/c++ seem to require additional flag to link things properly and CMake doesn't know about that.

To use /usr/bin/c++ as your compiler run cmake with -DCMAKE_CXX_COMPILER=/usr/bin/c++.

Also, CMAKE_PREFIX_PATH variable sets destination dir where your project' files should be installed. It has nothing to do with CMake installation prefix and CMake itself already know this.

Android: How to turn screen on and off programmatically?

If your app is a system app,you can use PowerManager.goToSleep() to turn screen off,you requires a special permission

before you use goToSleep(), you need use reflection just like:

public static void goToSleep(Context context) {
    PowerManager powerManager= (PowerManager)context.getSystemService(Context.POWER_SERVICE);
    try {
        powerManager.getClass().getMethod("goToSleep", new Class[]{long.class}).invoke(powerManager, SystemClock.uptimeMillis());
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    } catch (InvocationTargetException e) {
        e.printStackTrace();
    } catch (NoSuchMethodException e) {
        e.printStackTrace();
    }
}

Now,you can use goToSleep() to turn screen off.

This is what happens when the power key is pressed to turn off the screen.

Split page vertically using CSS

Check out this fiddle:

http://jsfiddle.net/G6N5T/1574/

CSS/HTML code:

_x000D_
_x000D_
.wrap {_x000D_
    width: 100%;_x000D_
    overflow:auto;_x000D_
}_x000D_
_x000D_
.fleft {_x000D_
    float:left; _x000D_
    width: 33%;_x000D_
background:lightblue;_x000D_
    height: 400px;_x000D_
}_x000D_
_x000D_
.fcenter{_x000D_
    float:left;_x000D_
    width: 33%;_x000D_
    background:lightgreen;_x000D_
    height:400px;_x000D_
    margin-left:0.25%;_x000D_
}_x000D_
_x000D_
.fright {_x000D_
float: right;_x000D_
    background:pink;_x000D_
    height: 400px;_x000D_
    width: 33.5%;_x000D_
    _x000D_
}
_x000D_
<div class="wrap">_x000D_
    <!--Updated on 10/8/2016; fixed center alignment percentage-->_x000D_
    <div class="fleft">Left</div>_x000D_
    <div class="fcenter">Center</div>_x000D_
    <div class="fright">Right</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

This uses the CSS float property for left, right, and center alignments of divs on a page.

Send cookies with curl

You can use -b to specify a cookie file to read the cookies from as well.

In many situations using -c and -b to the same file is what you want:

curl -b cookies.txt -c cookies.txt http://example.com

Further

Using only -c will make curl start with no cookies but still parse and understand cookies and if redirects or multiple URLs are used, it will then use the received cookies within the single invoke before it writes them all to the output file in the end.

The -b option feeds a set of initial cookies into curl so that it knows about them at start, and it activates curl's cookie parser so that it'll parse and use incoming cookies as well.

See Also

The cookies chapter in the Everything curl book.

ng-if check if array is empty

To overcome the null / undefined issue, try using the ? operator to check existence:

<p ng-if="post?.capabilities?.items?.length > 0">
  • Sidenote, if anyone got to this page looking for an Ionic Framework answer, ensure you use *ngIf:

    <p *ngIf="post?.capabilities?.items?.length > 0">
    

How to get UTF-8 working in Java webapps?

About CharsetFilter mentioned in @kosoant answer ....

There is a build in Filter in tomcat web.xml (located at conf/web.xml). The filter is named setCharacterEncodingFilter and is commented by default. You can uncomment this ( Please remember to uncomment its filter-mapping too )

Also there is no need to set jsp-config in your web.xml (I have test it for Tomcat 7+ )

MySQL config file location - redhat linux server

The information you want can be found by running

mysql --help

or

mysqld --help --verbose

I tried this :

    mysql --help | grep Default -A 1

And the output:

                      (Defaults to on; use --skip-auto-rehash to disable.)
  -A, --no-auto-rehash 
--
                      (Defaults to on; use --skip-line-numbers to disable.)
  -L, --skip-line-numbers 
--
                      (Defaults to on; use --skip-column-names to disable.)
  -N, --skip-column-names 
--
                      (Defaults to on; use --skip-reconnect to disable.)
  -s, --silent        Be more silent. Print results with a tab as separator,
--
  --default-auth=name Default authentication client-side plugin to use.
  --binary-mode       By default, ASCII '\0' is disallowed and '\r\n' is
--
Default options are read from the following files in the given order:
/etc/my.cnf /etc/mysql/my.cnf /usr/etc/my.cnf ~/.my.cnf 

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

The answer from Judah did not work for me (or is not complete) as the application was exiting after the first BeginOutputReadLine();

This works for me as a complete snippet, reading the constant output of a ping:

        var process = new Process();
        process.StartInfo.FileName = "ping";
        process.StartInfo.Arguments = "google.com -t";
        process.StartInfo.RedirectStandardOutput = true;
        process.StartInfo.UseShellExecute = false;
        process.OutputDataReceived += (sender, a) => Console.WriteLine(a.Data);
        process.Start();
        process.BeginOutputReadLine();
        process.WaitForExit();

Whether a variable is undefined

function my_url (base, opt)
{
    var retval = ["" + base];
    retval.push( opt.page_name ? "&page_name=" + opt.page_name : "");
    retval.push( opt.table_name ? "&table_name=" + opt.table_name : "");
    retval.push( opt.optionResult ? "&optionResult=" + opt.optionResult : "");
    return retval.join("");
}

my_url("?z=z",  { page_name : "pageX" /* no table_name and optionResult */ } );

/* Returns:
     ?z=z&page_name=pageX
*/

This avoids using typeof whatever === "undefined". (Also, there isn't any string concatenation.)

Shuffling a list of objects

from random import random
my_list = range(10)
shuffled_list = sorted(my_list, key=lambda x: random())

This alternative may be useful for some applications where you want to swap the ordering function.

What issues should be considered when overriding equals and hashCode in Java?

There are two methods in super class as java.lang.Object. We need to override them to custom object.

public boolean equals(Object obj)
public int hashCode()

Equal objects must produce the same hash code as long as they are equal, however unequal objects need not produce distinct hash codes.

public class Test
{
    private int num;
    private String data;
    public boolean equals(Object obj)
    {
        if(this == obj)
            return true;
        if((obj == null) || (obj.getClass() != this.getClass()))
            return false;
        // object must be Test at this point
        Test test = (Test)obj;
        return num == test.num &&
        (data == test.data || (data != null && data.equals(test.data)));
    }

    public int hashCode()
    {
        int hash = 7;
        hash = 31 * hash + num;
        hash = 31 * hash + (null == data ? 0 : data.hashCode());
        return hash;
    }

    // other methods
}

If you want get more, please check this link as http://www.javaranch.com/journal/2002/10/equalhash.html

This is another example, http://java67.blogspot.com/2013/04/example-of-overriding-equals-hashcode-compareTo-java-method.html

Have Fun! @.@

Difference between 'cls' and 'self' in Python classes?

This is very good question but not as wanting as question. There is difference between 'self' and 'cls' used method though analogically they are at same place

def moon(self, moon_name):
    self.MName = moon_name

#but here cls method its use is different 

@classmethod
def moon(cls, moon_name):
    instance = cls()
    instance.MName = moon_name

Now you can see both are moon function but one can be used inside class while other function name moon can be used for any class.

For practical programming approach :

While designing circle class we use area method as cls instead of self because we don't want area to be limited to particular class of circle only .

Get number of digits with JavaScript

The length property returns the length of a string (number of characters).

The length of an empty string is 0.

var str = "Hello World!";
var n = str.length;

The result of n will be: 12

    var str = "";
    var n = str.length;

The result of n will be: 0


Array length Property:


The length property sets or returns the number of elements in an array.

var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.length;

The result will be: 4

Syntax:

Return the length of an array:

array.length

Set the length of an array:

array.length=number

Java compiler level does not match the version of the installed Java project facet

You can change project facet from Project --> Properties --> Project Facet --> Java --> {required JDK version}

using wildcards in LDAP search filters/queries

A filter argument with a trailing * can be evaluated almost instantaneously via an index lookup. A leading * implies a sequential search through the index, so it is O(N). It will take ages.

I suggest you reconsider the requirement.

Remove file from SVN repository without deleting local copy

Rename your file, commit the changes including the "deleted" file, and don't include the new (renamed) file.

Rename your file back.

How to download source in ZIP format from GitHub?

I was facing same problem but accidentlty I sorted this problem. 1) Login in github 2) Click on Fork Button at Top Right. 3) After above step you can see Clone or download in Green color under <> Code Tab.

Is there a way to cast float as a decimal without rounding and preserving its precision?

Have you tried:

SELECT Cast( 2.555 as decimal(53,8))

This would return 2.55500000. Is that what you want?

UPDATE:

Apparently you can also use SQL_VARIANT_PROPERTY to find the precision and scale of a value. Example:

SELECT SQL_VARIANT_PROPERTY(Cast( 2.555 as decimal(8,7)),'Precision'),
SQL_VARIANT_PROPERTY(Cast( 2.555 as decimal(8,7)),'Scale')

returns 8|7

You may be able to use this in your conversion process...

DateTime.Today.ToString("dd/mm/yyyy") returns invalid DateTime Value

In addition to what the other answers have said, note that the '/' character in "dd/MM/yyyy" is not a literal character: it represents the date separator of the current user's culture. Therefore, if the current culture uses yyyy-MM-dd dates, then when you call toString it will give you a date such as "31-12-2016" (using dashes instead of slashes). To force it to use slashes, you need to escape that character:

DateTime.Now.ToString("dd/MM/yyyy")     --> "19-12-2016" for a Japanese user
DateTime.Now.ToString("dd/MM/yyyy")     --> "19/12/2016" for a UK user
DateTime.Now.ToString("dd\\/MM\\/yyyy") --> "19/12/2016" independent of region