length EXPR
    length  Returns the length in *characters* of the value of EXPR. If EXPR
            is omitted, returns the length of $_. If EXPR is undefined,
            returns "undef".

            This function cannot be used on an entire array or hash to find
            out how many elements these have. For that, use "scalar @array"
            and "scalar keys %hash", respectively.

            Like all Perl character operations, length() normally deals in
            logical characters, not physical bytes. For how many bytes a
            string encoded as UTF-8 would take up, use
            "length(Encode::encode_utf8(EXPR))" (you'll have to "use Encode"
            first). See Encode and perlunicode.