Iterators

Enumerate

Index and Value

enumerate pairs each item with its position, useful when building indexed output.

Program

Play the program to build a numbered report from a list of words.

enumerate.rs 
fn main() {
    let words = vec!["a", "b", "c"];
    let mut report = String::new();
    for (i, word) in words.iter().enumerate() {
        report.push_str(&format!("{i}:{word} "));
    }
    println!("{}", report.trim());
}
enumerate `enumerate` yields `(index, item)` pairs.
tuple binding `for (i, word)` destructures each pair.
trim `report.trim()` drops the trailing space.