Tutorial by Examples: v

Exceptions are powerful, but a single overzealous except clause can take it all away in a single line. try: res = get_result() res = res[0] log('got result: %r' % res) except: if not res: res = '' print('got exception') This example demonstrates 3 symptoms of t...

GetHashCode has major performance effects on Dictionary<> and HashTable. Good GetHashCode Methods should have an even distribution every integer should have a roughly equal chance of returning for a random instance if your method returns the same integer (e.g. the constant '999') for e...

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In this example, we'll create a simple echo server that will listen on the specified port, and being able to handle new connections: #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/socket.h> #include <sys/types.h> #include <arpa/inet.h&...

Create a new Console Application Add the NuGet package Microsoft.CodeAnalysis Import the namespaces Microsoft.CodeAnalysis.MSBuild, System.Linq and Microsoft.CodeAnalysis.CSharp.Syntax Write the following example code in the Main method: // Declaring a variable with the current project file ...

Create a new console application with one line in the Main method: Console.WriteLine("Hello World") Remember the path to the .vbproj file and replace it in the example. Create a new Console Application and install the Microsoft.CodeAnalysis NuGet package and try the following code: Cons...

you can custom class below one private final String PROTOCOL_CONTENT_TYPE = String.format("application/json; charset=%s", PROTOCOL_CHARSET); public BooleanRequest(int method, String url, String requestBody, Response.Listener<Boolean> listener, Response.ErrorListener errorList...

If the shift count value is a negative value then both left shift and right shift operations are undefined1: int x = 5 << -3; /* undefined */ int x = 5 >> -3; /* undefined */ If left shift is performed on a negative value, it's undefined: int x = -5 << 3; /* undefined */ I...

#Region directive can now be placed inside methods and can even span over methods, classes and modules. #Region "A Region Spanning A Class and Ending Inside Of A Method In A Module" Public Class FakeClass 'Nothing to see here, just a fake class. End Class Module Extensi...

Variables exist within a specific scope, much like in in JavaScript. If you declare a variable outside of a block, it can be used throughout the sheet. $blue: dodgerblue; .main { background: $blue; p { background: #ffffff; color: $blue; } } .header { ...

In the below example value in map $color-array is treated as list of pairs. SCSS Input $color-array:( black: #4e4e4e, blue: #0099cc, green: #2ebc78 ); @each $color-name, $color-value in $color-array { .bg-#{$color-name} { background: $color-value; } } ...

Labeling the alternatives inside a rule starting with the # operator tells ANTLR to generate listener methods for each label corresponding to the alternative. By specifying a label for each alternative in the following rule: // Rule type : int #typeInt | short #typeShort | long ...

Specifying the -gui command line option when running an ANTLR grammar in the test rig will result in a window popping up with a visual representation of the parse tree. For example: Given the following grammar: JSON.g4 /** Taken from "The Definitive ANTLR 4 Reference" by Terence Parr */...

Setting a top-level property compileOnSave signals to the IDE to generate all files for a given tsconfig.json upon saving. { "compileOnSave": true, "compilerOptions": { ... }, "exclude": [ ... ] } This feature is available...

Due to the vulnerability caused by CSRF, it is generally considered a good practice to check for an AntiForgeryToken on all HttpPosts unless there is a good reason to not do it (some technical issue with the post, there is another authentication mechanism and/or the post does not mutate state like s...

For a 12hour time format one can use: ^(?:0?[0-9]|1[0-2])[-:][0-5][0-9]\s*[ap]m$ Where (?:0?[0-9]|1[0-2]) is the hour [-:] is the separator, which can be adjusted to fit your need [0-5][0-9] is the minute \s*[ap]m followed any number of whitespace characters, and am or pm If you need th...

Servant is a library for declaring APIs at the type-level and then: write servers (this part of servant can be considered a web framework), obtain client functions (in haskell), generate client functions for other programming languages, generate documentation for your web applications and m...

PresenceOf - Validates that a value is not null or empty string $validator->add('name', new \Phalcon\Validation\Validator\PresenceOf([ 'message' => 'The name is required' ])); Email - Checks if a value has a correct e-mail format $validator->add('email', new \Phalcon\Validation\Va...

2.1.3 1. Preview Different Devices There is a preview panel at the right of the android studio. In thispanel there is a button with device name with which you are previewing the UI of your app like this . Click on small dropdown indicator of this and a floating panel will appear with all the pr...

To find out what packages your project directly depends on, you can simply use this command: stack list-dependencies This way you can find out what version of your dependencies where actually pulled down by stack. Haskell projects frequently find themselves pulling in a lot of libraries indirec...