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Sometimes, when you have local changes incompatible with remote changes (ie, when you cannot fast-forward the remote branch, or the remote branch is not a direct ancestor of your local branch), the only way to push your changes is a force push. git push -f or git push --force Important not...

Tk is the standard graphical user interface (GUI) for Ruby. It provides a cross-platform GUI for Ruby programs. Example code: require "tk" TkRoot.new{ title "Hello World!" } Tk.mainloop The result: Step by Step explanation: require "tk" Load the tk package...

Open a new blank document in the MATLAB Editor (in recent versions of MATLAB, do this by selecting the Home tab of the toolstrip, and clicking on New Script). The default keyboard shortcut to create a new script is Ctrl-n. Alternatively, typing edit myscriptname.m will open the file myscriptname.m ...

for loops iterate over a collection of items, such as list or dict, and run a block of code with each element from the collection. for i in [0, 1, 2, 3, 4]: print(i) The above for loop iterates over a list of numbers. Each iteration sets the value of i to the next element of the list. So f...

import random shuffle() You can use random.shuffle() to mix up/randomize the items in a mutable and indexable sequence. For example a list: laughs = ["Hi", "Ho", "He"] random.shuffle(laughs) # Shuffles in-place! Don't do: laughs = random.shuffle(laughs) p...

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...

Protocols may define associated type requirements using the associatedtype keyword: protocol Container { associatedtype Element var count: Int { get } subscript(index: Int) -> Element { get set } } Protocols with associated type requirements can only be used as generic constraints:...

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...

Standard Creation It is recommended to use this form only when creating regex from dynamic variables. Use when the expression may change or the expression is user generated. var re = new RegExp(".*"); With flags: var re = new RegExp(".*", "gmi"); With a backsl...

var re = /[a-z]+/; if (re.test("foo")) { console.log("Match exists."); } The test method performs a search to see if a regular expression matches a string. The regular expression [a-z]+ will search for one or more lowercase letters. Since the pattern matches the string,...

git remote add upstream git-repository-url Adds remote git repository represented by git-repository-url as new remote named upstream to the git repository

Assuming you set the upstream (as in the "setting an upstream repository") git fetch remote-name git merge remote-name/branch-name The pull command combines a fetch and a merge. git pull The pull with --rebase flag command combines a fetch and a rebase instead of merge. git pull ...

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...

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 ...