String And Bytes Methods

Strings are valid UTF-8 text values. Bytes are raw byte sequences. The two types intentionally have different indexing rules: String indexes are byte offsets that must land on UTF-8 boundaries, while bytes indexes address raw u8 values.

String Search And Transform

String helpers include len, is_empty, contains, find, starts_with, ends_with, strip_prefix, strip_suffix, to_upper, to_lower, trim, trim_start, trim_end, replace, repeat, and slice.

fn main() {
    let label = "  Quest.Gold ".trim().replace(".", "_").to_lower();
    let kind = label.slice(0, 5);
    let item = label.strip_prefix("quest_").unwrap_or("");
    return kind + ":" + item;
}

find, strip_prefix, and strip_suffix return Option.

Splitting, Parsing, And Characters

split, split_lines, and split_whitespace produce arrays. split_once returns Option<(String, String)>. Parsing helpers return Option so invalid input can be handled without a VM trap.

fn main() {
    let parts = "count=3 enabled=true".split_whitespace();
    let (_, count_text) = parts[0].split_once("=").unwrap_or(("count", "0"));
    let (_, enabled_text) = parts[1].split_once("=").unwrap_or(("enabled", "false"));
    let count = count_text
        .parse_i64()
        .unwrap_or(0);
    let enabled = enabled_text
        .parse_bool()
        .unwrap_or(false);
    return enabled && count == 3;
}

Use chars for Unicode scalar values and bytes for UTF-8 bytes.

fn main() {
    let first = "gold".chars().next().unwrap_or('\0');
    return first.to_string().to_upper();
}

Bytes

Bytes support len, is_empty, slice, get, read_u32_le, read_u32_be, to_hex, iter, and values. bytes::from_hex returns Result because malformed hex text has a recoverable error message.

fn main() {
    let decoded = bytes::from_hex("01000000");
    let bytes = result::unwrap_or(decoded, b"");
    if bytes.len() >= 4 {
        return bytes.read_u32_le(0);
    }
    return 0;
}

Out-of-bounds byte reads and invalid string slice boundaries are VM diagnostics, not Option.