UTF-8 - rust-course

46.2.1Getting a slice from a UTF-8 string¶

Compiler error:

let s = "Салам";
println!("s: {}", &s[0..1]);

thread '<unnamed>' (52188) panicked at src/lib.rs:96:21:

end byte index 1 is not a char boundary; it is inside 'С' (bytes 0..2 of string)

stack backtrace:

   0: __rustc::rust_begin_unwind

             at /rustc/58cf8f9c35b355199727627d07ae34a4e2846d67/library/std/src/panicking.rs:679:5

   1: core::panicking::panic_fmt

             at /rustc/58cf8f9c35b355199727627d07ae34a4e2846d67/library/core/src/panicking.rs:80:14

   2: core::str::slice_error_fail_rt

   3: core::str::slice_error_fail

             at /rustc/58cf8f9c35b355199727627d07ae34a4e2846d67/library/core/src/str/mod.rs:70:5

   4: __rust_try

   5: run_user_code_1

   6: <evcxr::runtime::Runtime>::run_loop

   7: evcxr::runtime::runtime_hook

   8: evcxr_jupyter::main

note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

Runtime error (panic):

let s = String::from("Салам");
println!("s: {}", &s[0..1]);

Couldn't automatically determine type of variable `s`.
Please give it an explicit type.

We use the get() method:

{
  let s = String::from("Салам");
  if let Some(t) = s.get(0..1) {
    println!("s[0..1]: {t}");
  }
  if let Some(t) = s.get(0..2) {
    println!("s[0..2]: {t}");
  }
}

s[0..2]: С

()

46.2 UTF-8

46.2.1Getting a slice from a UTF-8 string¶