String

The string container type is a wrapper over a char array with automatic memory management, resizing and shrinking. It provides common functionality like substrings, string-ranges and string comparisons.

Working with Strings

Strings are created like any other struct type:

// Define the type and convert char array to String implicitly
var string: String = ""
// Or create a string explicitly
var string = String.create("")

note

String fulfills the Convertible and Constructable contracts so it can be used as a char reference, or created via a char array.

Substrings

Strings may be sliced into substrings. Substrings are parts of a string.

Creating a substring is easy:

var str: String = "Foo, Bar"

// Reads `Foo`
var foo = str.substring(from: 0, count: 3)

Alternatively, a substring can be constructed from from to to:

var str: String = "Foo, Bar"

// Reads `Foo`
var foo = str.substring(from: 0, to: 2)

danger

Both substring functions will result in a panic if the string does not have enough characters

String attributes

The length of a string is retrieved by accessing the length property:

var str: String = "Foo, Bar"

// Prints 8
print(str.length)

String ranges

String fulfills the Iterable contract, allowing it to be used by iterators like for loops:

var str: String = "Foo, Bar, Foobar"

// Use each character
for character in str {
    ...
}

String comparison

String fulfills the Comparable contract, allowing it to be compared against other strings:

var foo = "Foo"
var fooStr: String = "Foo"

// Compare
if foo == fooStr {
    
}

String Views

A string view is a non-owning reference to a string. It only holds an immutable reference, allowing comparison and iteration of the string. Views are faster to pass around and are generally favoured when ownership should remain on the string the view was created for.

A string view is created like this:

var str: String = "Foo, Bar"
var view = StringView.from(string: str)

// Iterate over the characters like it was a regular string
for character in view {
    ...
}