Tutorial by Examples: l

import random randint() Returns a random integer between x and y (inclusive): random.randint(x, y) For example getting a random number between 1 and 8: random.randint(1, 8) # Out: 8 randrange() random.randrange has the same syntax as range and unlike random.randint, the last value is no...

git log will display all your commits with the author and hash. This will be shown over multiple lines per commit. (If you wish to show a single line per commit, look at onelineing). Use the q key to exit the log. By default, with no arguments, git log lists the commits made in that reposito...

git log --oneline will show all of your commits with only the first part of the hash and the commit message. Each commit will be in a single line, as the oneline flag suggests. The oneline option prints each commit on a single line, which is useful if you’re looking at a lot of commits. - sou...

About Protocols A Protocol specifies initialisers, properties, functions, subscripts and associated types required of a Swift object type (class, struct or enum) conforming to the protocol. In some languages similar ideas for requirement specifications of subsequent objects are known as ‘interfaces...

break statement When a break statement executes inside a loop, control flow "breaks" out of the loop immediately: i = 0 while i < 7: print(i) if i == 4: print("Breaking from loop") break i += 1 The loop conditional will not be evaluated a...

There are several flags you can specify to alter the RegEx behaviour. Flags may be appended to the end of a regex literal, such as specifying gi in /test/gi, or they may be specified as the second argument to the RegExp constructor, as in new RegExp('test', 'gi'). g - Global. Finds all matches inst...

To stage a file for committing, run git add <filename>

git add -A 2.0 git add . In version 2.x, git add . will stage all changes to files in the current directory and all its subdirectories. However, in 1.x it will only stage new and modified files, not deleted files. Use git add -A, or its equivalent command git add --all, to stage all ch...

You can make Git ignore certain files and directories — that is, exclude them from being tracked by Git — by creating one or more .gitignore files in your repository. In software projects, .gitignore typically contains a listing of files and/or directories that are generated during the build proces...

Changing the text of an existing UILabel can be done by accessing and modifying the text property of the UILabel. This can be done directly using String literals or indirectly using variables. Setting the text with String literals Swift label.text = "the new text" Objective-C // Do...

Setting a specific Seed will create a fixed random-number series: random.seed(5) # Create a fixed state print(random.randrange(0, 10)) # Get a random integer between 0 and 9 # Out: 9 print(random.randrange(0, 10)) # Out: 4 Resetting the seed will create the same &qu...

import java.awt.Image; import javax.imageio.ImageIO; ... try { Image img = ImageIO.read(new File("~/Desktop/cat.png")); } catch (IOException e) { e.printStackTrace(); }

Optionals are a generic enum type that acts as a wrapper. This wrapper allows a variable to have one of two states: the value of the user-defined type or nil, which represents the absence of a value. This ability is particularly important in Swift because one of the stated design objectives of the ...

x > y x < y These operators compare two types of values, they're the less than and greater than operators. For numbers this simply compares the numerical values to see which is larger: 12 > 4 # True 12 < 4 # False 1 < 4 # True For strings they will compare lexicographical...

x != y This returns True if x and y are not equal and otherwise returns False. 12 != 1 # True 12 != '12' # True '12' != '12' # False

x == y This expression evaluates if x and y are the same value and returns the result as a boolean value. Generally both type and value need to match, so the int 12 is not the same as the string '12'. 12 == 12 # True 12 == 1 # False '12' == '12' # True 'spam' == 'spam' # True 'spam' == ...

Use the import statement: >>> import random >>> print(random.randint(1, 10)) 4 import module will import a module and then allow you to reference its objects -- values, functions and classes, for example -- using the module.name syntax. In the above example, the random module...

Instead of importing the complete module you can import only specified names: from random import randint # Syntax "from MODULENAME import NAME1[, NAME2[, ...]]" print(randint(1, 10)) # Out: 5 from random is needed, because the python interpreter has to know from which resource it...

A basic "Hello, World!" program in Haskell can be expressed concisely in just one or two lines: main :: IO () main = putStrLn "Hello, World!" The first line is an optional type annotation, indicating that main is a value of type IO (), representing an I/O action which "...

from module_name import * for example: from math import * sqrt(2) # instead of math.sqrt(2) ceil(2.7) # instead of math.ceil(2.7) This will import all names defined in the math module into the global namespace, other than names that begin with an underscore (which indicates that the wri...