Julia 1.0 Programming Complete Reference Guide

Unicode and UTF-8

In Julia, string literals are encoded using UTF-8. UTF-8 is a variable-width encoding, meaning that not all characters are represented using the same number of bytes. For example, ASCII characters are encoded using a single byte—but other characters can use up to four bytes. This means that not every byte index into a UTF-8 string is necessarily a valid index for a corresponding character. If you index into a string at such an invalid byte index, an error will be thrown. Here is what I mean:

julia> str = "Søren Kierkegaard was a Danish Philosopher" 
julia> str[1] 
'S': ASCII/Unicode U+0053 (category Lu: Letter, uppercase) 

We can correctly retrieve the character at index 1:

julia> str[2] 'ø': Unicode U+00f8 (category Ll: Letter, ...