use warnings;
use strict;
use YAPE::Regex::Explain;
print YAPE::Regex::Explain->new('[^0-9]{1,1}')->explain();

__END__
The regular expression:

(?-imsx:[^0-9]{1,1})

matches as follows:

NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  [^0-9]{1,1}              any character except: '0' to '9' (between
                           1 and 1 times (matching the most amount
                           possible))
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------