How to get UTF-8 index of char in Rust

Question

I'm very new to rust. How I can to get UTF-8 index of char symbol in Rust.

Here you have a reference to utf table.

let bracket = '[';

fn get_utf(c:&[u8])->&str{
  // don't know how to obtain utf index
}

let result = get_utf(bracket); // 005B

I tried this function, but it does not work in a way I expect.

This crate might be useful, but I don't know how to use it.

Sorry, not much of my effort.

UTF-8 is a variable length multi-byte encoding for all symbols ("code points") of all scripts in Unicode, a numbering of code points. For 7bits UTF-8 == ASCII, single byte, and '[' casted to int is 0x5B == 91. — Joop Eggen
– Joop Eggen, Commented Jan 24, 2021 at 18:03

kmdreko · Accepted Answer · 2021-02-18 04:49:12Z

5

A char in Rust represents a Unicode scalar value. You can use as to cast it to a u32:

let bracket = '[';
let result = bracket as u32;

println!("{:04X}", result); // prints "005B"

See also: How to get a char's unicode value?

edited Feb 18, 2021 at 4:49

answered Jan 24, 2021 at 18:15

kmdreko

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2 Comments

Ömer Erden Over a year ago

Since OP is new to Rust and wants to assign value into a variable, this might support the answer : let result = format!("{:04X}", bracket as u32);

kmdreko Over a year ago

I edited it to be a little more explicit. Its not clear to me what OP wants to use it for, so I don't know whether it should be an integer or a string. But I hope the example helps regardless.

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