str::array_split for splitting a string into a constant number of substrings #102905
Open
Description
Related to:
The idea is to provide an API similar to split_once, but allowing the programmer to specify any number of substrings at compile time, instead of being limited to two (one split) or relying on splitn at runtime.
This is helpful for many cases where a programmer wants exactly N substrings, no more and no less, and knows N at compile time. splitn can work for this use case, but since you get an iterator out, there's no concise way to get the substrings into an array. You could also have less than N substrings.
API
pub fn array_split<const N: usize, 'a, P: Pattern<'a>>(&'a self, delimiter: P) -> Option<[&'a str; N]>Usage example
let static_format = "abc 123 xyz The rest of the string";
let parts: [&str; 4] = static_format.array_split(char::is_whitespace).unwrap();
// or using turbofish to specify # of substrings
let parts = static_format.array_split::<4>(char::is_whitespace).unwrap();
assert_eq!(parts, ["abc", "123", "xyz", "The rest of the string"]);Returning an array enables nice features like infallible destructuring:
let line = "John Doe,Engineer,Kansas,555-555-5555,This is a comment about John, who is a hard worker, and loves to fish.";
let [name, occupation, state, phone_num, comment] = line.array_split().unwrap();
assert_eq!(name, "John Doe");
assert_eq!(phone_num, "555-555-5555");
assert_eq!(comment, "This is a comment about John, who is a hard worker, and loves to fish.");@rustbot label +T-libs-api +A-str +A-array +A-const-generics