Rust update values in a hash - count words

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examples/hashes/count-words/src/main.rs

use std::collections::HashMap;

fn main() {
    let fruits = ["apple", "banana", "peach", "apple"];
    let mut counter = HashMap::new();

    for fruit in fruits {
        println!("{}", fruit);
        *counter.entry(fruit).or_insert(0) += 1;
    }
    println!("{:#?}", counter);
}