convert a number from base 2 to base 8 in rust

main.rs
fn binary_to_octal(binary_num: &str) -> String {
    // Split the binary number into groups of 3 digits (starting from right)
    let binary_groups = binary_num
        .chars()
        .rev()
        .collect::<String>()
        .as_bytes()
        .chunks(3)
        .map(|chunk| std::str::from_utf8(chunk).unwrap())
        .collect::<Vec<_>>();
    
    // Convert each binary group to its octal equivalent and combine
    let octal_num = binary_groups.iter()
        .map(|&group| i32::from_str_radix(&group.to_owned(), 2).unwrap())
        .rev()
        .fold(String::new(), |acc, &octal| format!("{}{}", acc, octal));

    // Return the octal number
    octal_num
}
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main.rs
let binary_num = "10111010";
let octal_num = binary_to_octal(binary_num);
println!("The octal conversion of {} is {}", binary_num, octal_num);
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main.rs
The octal conversion of 10111010 is 272
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