Stage 7.8: String Slice

A string slice is a reference to a sequence of bytes in memory that must always be valid utf-8.

A string slice (a sub-slice) of a str slice, must also be valid utf-8.

Common methods of &str:

• len gets the length of the string literal in bytes (not number of characters).
• starts_with / ends_with for basic testing.
• is_empty returns true if zero length.
• find returns an Option<usize> of the first position of some text.

Further information:

• https://doc.rust-lang.org/book/ch04-03-slices.html