pypama 1.0

This package provides a pattern matching for list of objects. Just as Regex provides regular expression for strings, this package provides regular expression for other type of lists.

An example is worth a thousand words: assume you have a list

>>> example_list = ['a', 'a', 1, '', None, 'b', 'c',  'e']

For some reason, you know that there is an int and a None, and you want to extract that number and the 2 strings following the None

>>> from pypama import build_pattern, is_int, is_none
>>> g = build_pattern((~is_int).star(False), '(', is_int, ')', '.*', is_none, '(',ANY,ANY, ')')
>>> g.match(example_list).groups()
[[1], ['b', 'c']]

• (~is_int) will matching anything that’s not an integer

• .star(False): equivalent to *? in regular expression: repeat as many as necessary

• parenthesis are for capturing groups

• .* is short for ANY.star() (match anything, repeatedly)

Therefore the pattern above reads as follow: match anything that’s not an int, repeatedly, until you find an int that you capture in group 1. Then match anything until you find a None. That must be followed by two elements that you capture in group 2.

This is therefore very similar to the `re` package, but applied to a list and with matching that goes beyond strings.