Programming Perl, 4th Edition

length

length EXPR
length

This function returns the length in codepoints (programmer‐visible characters) of the scalar value EXPR. If EXPR is omitted, it returns the length of $_. (But be careful that the next thing doesn’t look like the start of an EXPR, or Perl’s lexer will get confused. For example, length < 10 won’t compile. When in doubt, use parentheses.)

Do not try to use length to find the size of an array or hash. Use scalar @array for the size of an array, and scalar keys %hash for the number of key/value pairs in a hash. (The scalar is typically omitted when redundant.)

To find the number of graphemes (user‐visible characters) in a string, either count them:

my $count = 0;
$count++ while our $string =~ /\X/g;

or use the CPAN Unicode::GCString module, which lets you work with a string as a sequence of graphemes instead of as a sequence of codepoints. That module also tells you how long a string is in print columns. That way you can still use printf justification and, if you’re creative, maybe even format and write, even though some codepoints occupy 0 columns, others 1 column, and still others 2 columns when printed.