Tutorial by Examples: ar

Two ways to replace: by regex or by exact match. Note: the original String object will be unchanged, the return value holds the changed String. Exact match Replace single character with another single character: String replace(char oldChar, char newChar) Returns a new string resulting from...

Equality: value equality x == y (1 == 1.0 # true) value inequality x == y (1 != 1.0 # false) strict equality x === y (1 === 1.0 # false) strict inequality x === y (1 !== 1.0 # true) Comparison: x > y x >= y x < y x <= y If types are compatible, comparison uses natural o...

Pretty much every header file should follow the include guard idiom: my-header-file.h #ifndef MY_HEADER_FILE_H #define MY_HEADER_FILE_H // Code body for header file #endif This ensures that when you #include "my-header-file.h" in multiple places, you don't get duplicate declara...

For the character entity character(len=5), parameter :: greeting = "Hello" a substring may be referenced with the syntax greeting(2:4) ! "ell" To access a single letter it isn't sufficient to write greeting(1) ! This isn't the letter "H" but greeting(1:...

Declare your interface with Retrofit2 annotations: public interface BackendApiClient { @Multipart @POST("/uploadFile") Call<RestApiDefaultResponse> uploadPhoto(@Part("file\"; filename=\"photo.jpg\" ") RequestBody photo); } Where RestApiDef...

The process.env property returns an object containing the user environment. It returns an object like this one : { TERM: 'xterm-256color', SHELL: '/usr/local/bin/bash', USER: 'maciej', PATH: '~/.bin/:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin', PWD: '/Users/maciej', EDITOR: 'vi...

You've made a stash and wish to checkout only some of the files in that stash. git checkout stash@{0} -- myfile.txt

Consider the following example assuming that you have a ';'-delimited CSV to load into your database. 1;max;male;manager;12-7-1985 2;jack;male;executive;21-8-1990 . . . 1000000;marta;female;accountant;15-6-1992 Create the table for insertion. CREATE TABLE `employee` ( `id` INT NOT NULL , ...

In other frameworks pagination is headache. Laravel makes it breeze, it can generate pagination by adding few lines of code in Controller and View. Basic Usage There are many ways to paginate items, but the simplest one is using the paginate method on query builder or an Eloquent query. Laravel ou...

// create an array with 2 elements var myArray = new [] { "one", "two" }; // enumerate through the array foreach(var item in myArray) { Console.WriteLine(item); } // output: // one // two // exchange the element on the first position // note that all collecti...

declare is used to set an execution directive for a block of code. The following directives are recognized: ticks encoding strict_types For instance, set ticks to 1: declare(ticks=1); To enable strict type mode, the declare statement is used with the strict_types declaration: declare(s...

Assuming we want to modify bit n of an integer primitive, i (byte, short, char, int, or long): (i & 1 << n) != 0 // checks bit 'n' i |= 1 << n; // sets bit 'n' to 1 i &= ~(1 << n); // sets bit 'n' to 0 i ^= 1 << n; // toggles the value of bit 'n' Us...

You must be very careful when providing a forwarding reference overload as it may match too well: struct A { A() = default; // #1 A(A const& ) = default; // #2 template <class T> A(T&& ); // #3 }; The intent here was that A is c...

# Extract strings with a specific regex df= df['col_name'].str.extract[r'[Aa-Zz]'] # Replace strings within a regex df['col_name'].str.replace('Replace this', 'With this') For information on how to match strings using regex, see Getting started with Regular Expressions.

Active patterns are just simple functions. Like functions you can define additional parameters: let (|HasExtension|_|) expected (uri : string) = let result = uri.EndsWith (expected, StringComparison.CurrentCultureIgnoreCase) match result with | true -> Some true | _ -> N...

C++11 std::string supports iterators, and so you can use a ranged based loop to iterate through each character: std::string str = "Hello World!"; for (auto c : str) std::cout << c; You can use a "traditional" for loop to loop through every character: std::stri...

This simple example provides an explanation on some functions I found extremely useful since I have started using MATLAB: cellfun, arrayfun. The idea is to take an array or cell class variable, loop through all its elements and apply a dedicated function on each element. An applied function can eith...

Since Matlab R2014b it is easily possible to achieve semi-transparent markers for line and scatter plots using undocumented features introduced by Yair Altman. The basic idea is to get the hidden handle of the markers and apply a value < 1 for the last value in the EdgeColorData to achieve the d...

Let's say we have a class MyClass with no constructor argument: class MyClass In Scala we can instantiate it using below syntax: val obj = new MyClass() Or we can simply write: val obj = new MyClass But, if not paid attention, in some cases optional parenthesis may produce some unexpecte...

Array.prototype.map(): Returns a new array with the results of calling a provided function on every element in the original array. The following code example takes an array of persons and creates a new array containing persons with a 'fullName' property var personsArray = [ { id: 1, f...