hasPrefix(_:)

true if the string begins with prefix; otherwise, false.

The comparison is both case sensitive and Unicode safe. The case-sensitive comparison will only match strings whose corresponding characters have the same case.

let cafe = "Café du Monde"

// Case sensitive
print(cafe.hasPrefix("café"))
// Prints "false"

The Unicode-safe comparison matches Unicode scalar values rather than the code points used to compose them. The example below uses two strings with different forms of the "é" character—the first uses the composed form and the second uses the decomposed form.

// Unicode safe
let composedCafe = "Café"
let decomposedCafe = "Cafe\u{0301}"

print(cafe.hasPrefix(composedCafe))
// Prints "true"
print(cafe.hasPrefix(decomposedCafe))
// Prints "true"