$ cargo run Compiling collections v0.1.0 (file:///projects/collections) error[E0277]: the type `String` cannot be indexed by `{integer}` --> src/main.rs:3:13 | 3 | let h = s1[0]; | ^^^^^ `String` cannot be indexed by `{integer}` | = help: the trait `Index<{integer}>` is not implemented for `String` = help: the following other types implement trait `Index<Idx>`: <String as Index<RangeFrom<usize>>> <String as Index<RangeFull>> <String as Index<RangeInclusive<usize>>> <String as Index<RangeTo<usize>>> <String as Index<RangeToInclusive<usize>>> <String as Index<std::ops::Range<usize>>> <str as Index<I>> For more information about this error, try `rustc --explain E0277`. error: could not compile `collections` due to previous error