MultiRange will make complex range sequences from a formatted string.

multi_range.py

class MultiRange:
    def __init__(self, range_str, **kwargs):
        """
        MultiRange return a complex number sequence from a formatted string.
        Range formats:
        'Start[:Stop[:Step]]' - Start number (or single number), stop number (optional), step value (optional)
        Groups are separated by ','.
        For example, `MultiRange('1:3,5,7:9')` will result in (1,2,3,5,7,8,9).

        Text substitution can be specified by adding a keyword argument of the same name.
        For example, `MultiRange('1:max', max=10)` will result in (1,2,3,4,5,6,7,8,9,10)

        Sequences are returned in the order specified in the range_str, and can contain duplicates if written as such.
        Use `sorted(set(range_maker(...)))` to sort and eliminate duplicates if desired.

        :type range_str: str
        :rtype : MultiRange
        """
        self.range_str = range_str

        # Substitute strings that match kwargs keys
        for k, v in kwargs.items():
            self.range_str = self.range_str.replace(k, str(v))

        self._range_items = self.range_str.split(',')

    def _parse(self, range_item):
        # Make a list of each int value in the range.
        item_data = [int(item) for item in range_item.split(':', 2)]
        if len(item_data) == 1:
            return item_data
        else:
            # Get the range parameters
            start, stop = item_data[:2]
            stop_off = int(start <= stop or -1)
            # If no step value, use the stop offset
            step = item_data[2] if len(item_data) == 3 else stop_off
            return range(start, stop + stop_off, step)

    def __contains__(self, item):
        for range_item in self._range_items:
            if item in self._parse(range_item):
                return True
        return False

    def __iter__(self):
        result = []
        for range_items in self._range_items:
            result.extend(self._parse(range_items))
        return iter(result)