Tutorial by Examples: c

One method is available for counting the number of occurrences of a sub-string in another string, str.count. str.count(sub[, start[, end]]) str.count returns an int indicating the number of non-overlapping occurrences of the sub-string sub in another string. The optional arguments start and end ...

Routes are defined in config/routes.rb. They are often defined as a group of related routes, using the resources or resource methods. resources :users creates the following seven routes, all mapping to actions of UsersController: get '/users', to: 'users#index' post '/users', ...

Signed integers can be of these types (the int after short, or long is optional): signed char c = 127; /* required to be 1 byte, see remarks for further information. */ signed short int si = 32767; /* required to be at least 16 bits. */ signed int i = 32767; /* required to be at least 16 bits */ ...

C99 The header <stdint.h> provides several fixed-width integer type definitions. These types are optional and only provided if the platform has an integer type of the corresponding width, and if the corresponding signed type has a two's complement representation of negative values. See the r...

The C language has three mandatory real floating point types, float, double, and long double. float f = 0.314f; /* suffix f or F denotes type float */ double d = 0.314; /* no suffix denotes double */ long double ld = 0.314l; /* suffix l or L denotes long double */ /* the differen...

Dictionaries are an unordered collection of keys and values. Values relate to unique keys and must be of the same type. When initializing a Dictionary the full syntax is as follows: var books : Dictionary<Int, String> = Dictionary<Int, String>() Although a more concise way of initia...

Add a key and value to a Dictionary var books = [Int: String]() //books = [:] books[5] = "Book 5" //books = [5: "Book 5"] books.updateValue("Book 6", forKey: 5) //[5: "Book 6"] updateValue returns the original value if one exists or nil. let previous...

A value in a Dictionary can be accessed using its key: var books: [Int: String] = [1: "Book 1", 2: "Book 2"] let bookName = books[1] //bookName = "Book 1" The values of a dictionary can be iterated through using the values property: for book in books.values { ...

The <article> element contains self-contained content like articles, blog posts, user comments or an interactive widget that could be distributed outside the context of the page, for example by RSS. When article elements are nested, the contents of the inner article node should be related t...

Syntax : history.replaceState(data, title [, url ]) This method modifies the current history entry instead of creating a new one. Mainly used when we want to update URL of the current history entry. window.history.replaceState("http://example.ca", "Sample Title", "/exam...

@media screen and (min-width: 720px) { body { background-color: skyblue; } } The above media query specifies two conditions: The page must be viewed on a normal screen (not a printed page, projector, etc). The width of the user's view port must be at least 720 pixels. I...

You can use the label's textColor property to apply a text color to the entire text of the label. Swift label.textColor = UIColor.redColor() label.textColor = UIColor(red: 64.0/255.0, green: 88.0/255.0, blue: 41.0/225.0, alpha: 1) Swift 3 label.textColor = UIColor.red label.textColor = UICol...

With a Frame When you know the exact dimensions you want to set for your label, you can initialize a UILabel with a CGRect frame. Swift let frame = CGRect(x: 0, y: 0, width: 200, height: 21) let label = UILabel(frame: frame) view.addSubview(label) Objective-C CGRect frame = CGRectMake(0, 0,...

Use new Date() to generate a new Date object containing the current date and time. Note that Date() called without arguments is equivalent to new Date(Date.now()). Once you have a date object, you can apply any of the several available methods to extract its properties (e.g. getFullYear() to get t...

Magic (also called dunder as an abbreviation for double-underscore) methods in Python serve a similar purpose to operator overloading in other languages. They allow a class to define its behavior when it is used as an operand in unary or binary operator expressions. They also serve as implementation...

It is possible to emulate container types, which support accessing values by key or index. Consider this naive implementation of a sparse list, which stores only its non-zero elements to conserve memory. class sparselist(object): def __init__(self, size): self.size = size se...

class adder(object): def __init__(self, first): self.first = first # a(...) def __call__(self, second): return self.first + second add2 = adder(2) add2(1) # 3 add2(2) # 4

Jsoup can be used to extract links and email address from a webpage, thus "Web email address collector bot" First, this code uses a Regular expression to extract the email addresses, and then uses methods provided by Jsoup to extract the URLs of links on the page. public class JSoupTest {...

This example uses the Cars Table from the Example Databases. UPDATE Cars SET Status = 'READY' WHERE Id = 4 This statement will set the status of the row of 'Cars' with id 4 to "READY". WHERE clause contains a logical expression which is evaluated for each row. If a...

The general syntax for declaring a one-dimensional array is type arrName[size]; where type could be any built-in type or user-defined types such as structures, arrName is a user-defined identifier, and size is an integer constant. Declaring an array (an array of 10 int variables in this case) i...