String Methods

Methods available on String types.

Inspection

count

Returns the total number of characters in the string.

fn count(): Int

let greeting = "hello";
print(greeting.count()); // 5

indexOf

Returns the index of the first occurrence of sub, or Null if not found.

fn indexOf(sub: String): Int|Null

let sentence = "hello world";
print(sentence.indexOf(sub: "world")); // 6
print(sentence.indexOf(sub: "mars"));  // null

contains

Checks if the string contains the specified substring.

fn contains(sub: String): Bool

let sentence = "hello world";
if sentence.contains(sub: "hello") {
    print("Found!");
}

startsWith

Checks if the string begins with the specified substring.

fn startsWith(sub: String): Bool

let filename = "document.txt";
print(filename.startsWith(sub: "doc")); // true

endsWith

Checks if the string ends with the specified substring.

fn endsWith(sub: String): Bool

let imageName = "picture.png";
print(imageName.endsWith(sub: ".png")); // true

Transformation

lower

Converts the string to lowercase.

fn lower(): String

let shout = "HELLO";
print(shout.lower()); // "hello"

upper

Converts the string to uppercase.

fn upper(): String

let greeting = "hello";
print(greeting.upper()); // "HELLO"

trim

Removes whitespace from both the beginning and end of the string.

fn trim(): String

let userInput = "  hello  ";
print(userInput.trim()); // "hello"

trimLeft / ltrim

Removes whitespace from the beginning of the string.

fn trimLeft(): String

let s = "  hello";
print(s.trimLeft()); // "hello"

trimRight / rtrim

Removes whitespace from the end of the string.

fn trimRight(): String

let s = "hello  ";
print(s.trimRight()); // "hello"

replace

Replaces all occurrences of the old string with the new string.

fn replace(old: String, new: String): String

let template = "hello world";
print(template.replace(old: "world", new: "universe")); // "hello universe"

split

Splits the string into an array of substrings using the delimiter sep.

fn split(sep: String): Array<String>

let csvData = "apple,banana,cherry";
let items = csvData.split(sep: ",");
// items is ["apple", "banana", "cherry"]

substring

Extracts a portion of the string. If len is omitted, extracts to the end.

fn substring(start: Int, len: Int?): String

let phrase = "hello world";
print(phrase.substring(start: 0, len: 5)); // "hello"
print(phrase.substring(start: 6));         // "world"

reverse

Reverses the characters in the string.

fn reverse(): String

let word = "abc";
print(word.reverse()); // "cba"

repeat

Repeats the string n times.

fn repeat(n: Int): String

let star = "*";
print(star.repeat(n: 5)); // "*****"

pad

Pads the string to a certain length with another string.

fn pad(length: Int, padString: String = " ", type: Int = STR_PAD_RIGHT): String

let s = "Hello";
print(s.pad(length: 10, padString: ".")); // "Hello....."