Map Methods

Maps are script-owned value-keyed collections. Standard map helpers are designed for explicit lookup and explicit traversal; missing keys do not trap unless the script uses direct indexing. Key equality is defined by ValueKey, not by user-visible equality or ordering implementations.

Lookup And Update

Use has, get, and get_or when the key may be absent. get returns Option, while get_or returns the stored value or the fallback argument.

fn main() {
    let rewards = {"gold": 3, "xp": 10};
    let gold = rewards.get("gold").unwrap_or(0);
    let gems = rewards.get_or("gems", 0);
    return gold + gems;
}

set, remove, clear, extend, and merge mutate or combine maps. remove returns the removed value as Option.

fn main() {
    let rewards = {"gold": 3};
    rewards.set("xp", 10);
    let removed = rewards.remove("gold").unwrap_or(0);
    rewards.extend({"gems": 1});
    return removed + rewards.len();
}

Views And Entries

keys, values, and entries return iterators. keys yields the stored original key values, and entries yields MapEntry records with key and value fields. Non-string keys are not stringified by these helpers.

fn main() {
    let rewards = {"gold": 3, "xp": 10};
    let labels = rewards.keys().collect_array().sort().join(",");
    let total = rewards.values().collect_array().sum();
    return labels == "gold,xp" && total == 13;
}

Use entries when both key and value are needed in the same pipeline.

fn main() {
    let rewards = {"gold": 3, "xp": 10};
    let entry = rewards.entries()
        .find(|entry| entry.value >= 10)
        .unwrap_or(MapEntry { key: "", value: 0 });
    return entry.key;
}

Callback Helpers

Eager helpers such as map_values, filter, find, any, all, and count accept callbacks. Most helpers support either value-only callbacks or key-and-value callbacks where that is meaningful.

fn main() {
    let rewards = {"gold": 3, "xp": 10, "quest": 1};
    let doubled = rewards.map_values(|value| value * 2);
    let big = rewards.filter(|key, value| key.len() <= 4 && value >= 3);
    return doubled["xp"] + big.len();
}