Tutorial by Examples: pt

var directories = [ {name: 'users' , parent : null }, {name: 'distalx' , parent : 'users' }, {name: 'guest' , parent : 'users' }, {name: 'shared' , parent : 'users' }, {name: 'documents' , parent : 'distalx' }, {name: 'music' , parent : 'distalx' }, {name: 'desktop' , parent : '...

Use & to capture functions from other modules. You can use the captured functions directly as function parameters or within anonymous functions. Enum.map(list, fn(x) -> String.capitalize(x) end) Can be made more concise using &: Enum.map(list, &String.capitalize(&1)) Captu...

Exceptions represent programmer-level bugs like trying to access an array element that doesn’t exist. Errors are user-level issues like trying load a file that doesn’t exist. Because errors are expected during the normal execution of a program. Example: NSArray *inventory = @[@"Sam"...

Add 'exception' as a suffix Custom exception names should be suffixed with "-Exception". Below are correctly named exceptions: public class MyCustomException : Exception public class FooException : Exception

Subroutine arguments in Perl are passed by reference, unless they are in the signature. This means that the members of the @_ array inside the sub are just aliases to the actual arguments. In the following example, $text in the main program is left modified after the subroutine call because $_[0] in...

Command line You can use cpan to install modules directly from the command line: cpan install DBI This would be followed by possibly many pages of output describing exactly what it is doing to install the module. Depending on the modules being installed, it may pause and ask you questions. Int...

Use assert_raise to test if an exception was raised. assert_raise takes in an Exception and a function to be executed. test "invalid block size" do assert_raise(MerkleTree.ArgumentError, (fn() -> MerkleTree.new ["a", "b", "c"] end)) end Wrap a...

In some cases you might want to add an additional description to an enum value, for instance when the enum value itself is less readable than what you might want to display to the user. In such cases you can use the System.ComponentModel.DescriptionAttribute class. For example: public enum Possibl...

DataTables has the capability to enable or disable a number of its features, such as paging or searching. To choose these options, simply select them in your initialization: $(document).ready(function() { $('#tableid').DataTable( { "paging": false, //Turn off paging, all r...

Use "-x" to enable debug output of executed lines. It can be run on an entire session or script, or enabled programmatically within a script. Run a script with debug output enabled: $ bash -x myscript.sh Or $ bash --debug myscript.sh Turn on debugging within a bash script. It may ...

Dim aList as New List(Of String) aList.Add("one") aList.Add("two") aList.Add("three") For Each str As String in aList System.Console.WriteLine(str) Next Produces the following output: one two three Another option, would be to loop through using the ...

Your upstart script will need to be modified to use multiple IP addresses of the replica set. start on started mountall stop on shutdown respawn respawn limit 99 5 script # our example assumes you're using a replica set and/or oplog integreation export MONGO_URL='mongodb://mongo-a...

// initialize pubnub object var pubnub = new PubNub({ subscribeKey: "yourSubscribeKey", publishKey: "myPublishKey" // optional }) // get up to the last 100 messages // published to the channel pubnub.history( { channel: 'channel1' }, func...

For programs with a single source file, using gcc is simple. /* File name is hello_world.c */ #include <stdio.h> int main(void) { int i; printf("Hello world!\n"); } To compile the file hello_world.c from the command line: gcc hello_world.c gcc will then compil...

<script src="example.js"></script> The src attribute works like the href attribute on anchors: you can either specify an absolute or relative URL. The example above links to a file inside the same directory of the HTML document. This is typically added inside the <head&gt...

If you are inside a folder of a git repository it might be nice to show the current branch you are on. In ~/.bashrc or /etc/bashrc add the following (git is required for this to work): function prompt_command { # Check if we are inside a git repository if git status > /dev/null 2>&a...

Instead of linking to an external file, you can also include the JS code as-is in your HTML: <script> // JavaScript code </script>

Each Java Thread has an interrupt flag, which is initially false. Interrupting a thread, is essentially nothing more than setting that flag to true. The code running on that thread can check the flag on occasion and act upon it. The code can also ignore it completely. But why would each Thread have...

When a function returns an object (as opposed to using one that's passed in by the caller), be careful an exception doesn't cause the object to leak. function MakeStrings: TStrings; begin // Create a new object before entering the try-block. Result := TStringList.Create; try // Execu...

A try-finally block may be nested inside a try-except block. try AcquireResources; try UseResource; finally ReleaseResource; end; except on E: EResourceUsageError do begin HandleResourceErrors; end; end; If an exception occurs inside UseResource, then execution...