Skip to main content

String

A collection of unicode characters.

We expect all strings to be UTF-8 encoded!

var message: String = "Hello, world 👋"

Comparing Strings​

var word1 = "Cat"
var word2 = "Dog"

print("\{word1 == word2}") // Prints "false"
print("\{word1 != word2}") // Prints "true"

Escape Sequences​

Escape sequences allow you to embed non-printable characters and characters which would otherwise conflict with the languages syntax. String literals may contain the following escape sequences:

  • \n: Line break
  • \r: Carriage return (8.9)
  • \\: Backslash
  • \": Quote
  • \u{030A}: Unicode codepoints (see next section for more information)
  • \{<expr>}: Interpolation (see section interpolation)

Unicode Codepoints​

To insert unicode characters you can also use unicode codepoints. A unicode codepoint is written as \u{<value>}, where <value> is a placeholder for the codepoint's hexadecimal value, e.g. \u{00c5} for an Å. You can insert characters in different normalizations forms. The character Å can also be represented in the decomposed form \u{0041}\u{030A}.

var calendar_in_swedish = "kalendera\u{030A}r" // kalenderår

Note that codepoints such as \u{030A} are combined together with the leading character and are not treated as a separate characters. The length of this string is 10.

Interpolation​

String interpolation allows you to embed the values of variables or expressions into a string literal.

var name = "John"
var age = 18
print("Hello \{name}, over 18: \{age > 18}")

Properties​

byte_count​

byte_count: Int { get }

The number of bytes this string stores.

is_empty​

is_empty: Bool { get }

Whether the string has no characters in it.

length​

length: Int { get }

Number of unicode characters.

Methods​

appending​

appending(_ other: String) -> (String)

Returns a new string with other appended.

contains​

contains(_ other: String) -> (Bool)

Returns whether other is found in the string.

has_prefix​

has_prefix(_ prefix: String) -> (Bool)

Returns whether the string starts with the given prefix.

has_suffix​

has_suffix(_ suffix: String) -> (Bool)

Returns whether the string ends with the given suffix.

index​

index(of other: String, from: Int = 0) -> (Int?)

Returns the first index of other if found, starting the search from the given character.

inserting​

inserting(_ other: String, at index: Int) -> (String)

Returns a new string with other inserted into the string at the given character index.

lexicographically_precedes​

lexicographically_precedes(_ other: String) -> (Bool)

Returns whether the string should appear before other in a list.

This function doesn't implement proper ordering for all languages. It only works well for the latin alphabet.

lowercased​

lowercased() -> (String)

Returns a lowercase version of the string.

prefix​

prefix(_ max_length: Int) -> (String)

Returns a substring, up to the specified maximum length, starting from the beginning.

removing_all​

removing_all(_ other: String) -> (String)

Returns a string with all occurrences of other removed.

removing_subrange​

removing_subrange(from: Int, length: Int? = nil) -> (String)

Returns a string with the subrange removed.

from: Int

The starting character index

length: Int? = nil

The number of characters to remove. If not specified, the length will be the remainder after from.

replacing_all​

replacing_all(_ target: String, with replacement: String) -> (String)

Returns a string with all matches of target replaced by replacement.

reversed​

reversed() -> (String)

Returns a reversed version of the string.

split​

split(separator: String) -> ([String])

Returns a list of all segments obtained from splitting the string at every separator found in it.

substring​

substring(from: Int, length: Int? = nil) -> (String)

Returns a string containing only the specified range.

from: Int

The starting character index

length: Int? = nil

The number of characters to include. If not specified, the length will be the remainder after from.

suffix​

suffix(_ max_length: Int) -> (String)

Returns a substring, up to the specified maximum length, containing the final characters in the string.

trimmed​

trimmed() -> (String)

Returns a version with all leading and trailing whitespace removed.

uppercased​

uppercased() -> (String)

Returns an uppercase version of the string.