Tutorial by Examples: t

Arrays have fixed lengths that are known within the scope of their declarations. Nevertheless, it is possible and sometimes convenient to calculate array lengths. In particular, this can make code more flexible when the array length is determined automatically from an initializer: int array[] = {...

Accessing array values is generally done through square brackets: int val; int array[10]; /* Setting the value of the fifth element to 5: */ array[4] = 5; /* The above is equal to: */ *(array + 4) = 5; /* Reading the value of the fifth element: */ val = array[4]; As a side effect of...

You can filter what routes are available using constraints. There are several ways to use constraints including: segment constraints, request based constraints advanced constraints For example, a requested based constraint to only allow a specific IP address to access a route: constraints(...

The <nav> element is primarily intended to be used for sections that contain main navigation blocks for the website, this can include links to other parts of the web page (e.g. anchors for a table of contents) or other pages entirely. Inline items The following will display an inline set of ...

String literals in Swift are delimited with double quotes ("): let greeting = "Hello!" // greeting's type is String Characters can be initialized from string literals, as long as the literal contains only one grapheme cluster: let chr: Character = "H" // valid let chr...

Git will usually open an editor (like vim or emacs) when you run git commit. Pass the -m option to specify a message from the command line: git commit -m "Commit message here" Your commit message can go over multiple lines: git commit -m "Commit 'subject line' message here Mor...

var a = Math.random(); Sample value of a: 0.21322848065742162 Math.random() returns a random number between 0 (inclusive) and 1 (exclusive) function getRandom() { return Math.random(); } To use Math.random() to get a number from an arbitrary range (not [0,1)) use this function to get a...

The attribute tools:ignore can be used in xml files to dismiss lint warnings. BUT dismissing lint warnings with this technique is most of the time the wrong way to proceed. A lint warning must be understood and fixed... it can be ignored if and only if you have a full understanding of it's meaning...

git rm filename To delete the file from git without removing it from disk, use the --cached flag git rm --cached filename

Extensions can contain functions and computed/constant get variables. They are in the format extension ExtensionOf { //new functions and get-variables } To reference the instance of the extended object, self can be used, just as it could be used To create an extension of String that adds ...

Extensions can contain convenience initializers. For example, a failable initializer for Int that accepts a NSString: extension Int { init?(_ string: NSString) { self.init(string as String) // delegate to the existing Int.init(String) initializer } } let str1: NSString = &qu...

This example show how to subscribe, and once that is successful, publishing a message to that channel. It also demonstrates the full set of parameters that can be included in the subscribe's message callback function. pubnub = PUBNUB({ publish_key : 'your_pub_key', ...

import operator reduce(operator.mul, [10, 5, -3]) # Out: -150

reduce will not terminate the iteration before the iterable has been completly iterated over so it can be used to create a non short-circuit any() or all() function: import operator # non short-circuit "all" reduce(operator.and_, [False, True, True, True]) # = False # non short-circu...

# First falsy element or last element if all are truthy: reduce(lambda i, j: i and j, [100, [], 20, 10]) # = [] reduce(lambda i, j: i and j, [100, 50, 20, 10]) # = 10 # First truthy element or last element if all falsy: reduce(lambda i, j: i or j, [100, [], 20, 0]) # = 100 reduce(la...

When it comes to adding/removing channels to/from your channel groups, you need to have must have the manage permission for those channel groups. But you should never grant clients the permission to manage the channel groups that they will subscribe to. If they did, then they could add any channel t...

Presence works by sending messages when a user joins, leaves, or times out from a particular channel. You can listen for these messages to track who is in a channel, and how long since they did anything. First, make sure each user as a UUID. Set this when you initialize PubNub: var pubnub = PUBNUB...

In addition to .done, .fail and .always promise callbacks, which are triggered based on whether the request was successful or not, there is the option to trigger a function when a specific HTTP Status Code is returned from the server. This can be done using the statusCode parameter. $.ajax({ t...

For example, you can take the absolute value of each element: list(map(abs, (1, -1, 2, -2, 3, -3))) # the call to `list` is unnecessary in 2.x # Out: [1, 1, 2, 2, 3, 3] Anonymous function also support for mapping a list: map(lambda x:x*2, [1, 2, 3, 4, 5]) # Out: [2, 4, 6, 8, 10] or convert...

For example calculating the average of each i-th element of multiple iterables: def average(*args): return float(sum(args)) / len(args) # cast to float - only mandatory for python 2.x measurement1 = [100, 111, 99, 97] measurement2 = [102, 117, 91, 102] measurement3 = [104, 102, 95, 101] ...