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Rust program to modify the values of HashMap using the iter_mut() method

Rust | HashMap Example: Write a program to modify the values of HashMap using the iter_mut() method.
Submitted by Nidhi, on October 17, 2021

Problem Solution:

In this program, we will create a HashMap and then we will insert items into HashMap using the insert() function. After that, we will modify the value of HashMap using the iter_mut() method and print updated HashMap.

Program/Source Code:

The source code to modify the values of the HashMap using the iter_mut () method is given below. The given program is compiled and executed successfully.

// Rust program to modify the values of HashMap 
// using iter_mut() method

use std::collections::HashMap;

fn main() 
{
    let mut map = HashMap::new();

    map.insert("Key1", 101);
    map.insert("Key2", 102);
    map.insert("Key3", 103);
    map.insert("Key4", 104);

    for (_, val) in map.iter_mut() {
        *val = *val + 50 ;
    }
    
    println!("HashMap Keys/values:");
    for (key, val) in map.iter() {
        println!("{} -> {}", key, val);
    }
}

Output:

HashMap Keys/values:
Key4 -> 154
Key3 -> 153
Key1 -> 151
Key2 -> 152

Explanation:

Here, we created a HashMap. Then we inserted the item into HashMap and modified the value of HashMap using the iter_mut() method printed the updated HashMap.

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