Description:

This module exports a single function - make_partition_re. It takes as
its first argument a number between 0 and 1, representing a
percentage, and as its second argument a reference to a list of
strings. It returns a regular expression which is guaranteed to match
the percentage of the strings in the list represented by the number in
the first argument. More importantly, the regex returned is guaranteed
*not* to match the rest of the string in the list. That is, if the
inputs were '0.6' and a reference to a list of 100 strings, the
returned regex would match 60 of the strings in the list and not match
the other 40.