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
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
(you'll have to
first). See Encode and perlunicode.