Decimal number to hexadecimal string

Question

Does Rust have a set of functions that make converting a decimal integer to a hexadecimal string easy? I have no trouble converting a string to an integer, but I can't seem to figure out the opposite. Currently what I have does not work (and may be a bit of an abomination)

Editor's note - this code predates Rust 1.0 and no longer compiles.

pub fn dec_to_hex_str(num: uint) -> String {     let mut result_string = String::from_str("");     let mut i = num;     while i / 16 > 0 {         result_string.push_str(String::from_char(1, from_digit(i / 16, 16).unwrap()).as_slice());         i = i / 16;     }     result_string.push_str(String::from_char(1, from_digit(255 - i * 16, 16).unwrap()).as_slice());      result_string } 

Am I on the right track, or am I overthinking this whole thing?

Answer 1

You’re overthinking the whole thing.

assert_eq!(format!("{:x}", 42), "2a"); assert_eq!(format!("{:X}", 42), "2A"); 

That’s from std::fmt::LowerHex and std::fmt::UpperHex, respectively. See also a search of the documentation for "hex".