How do I extend, mimic, or emulate the range function?

Question

I made a little generator function for character ranges:

>>> def crange(start, end):
...     for i in range(ord(start), ord(end)+1):
...                     


        

Answer 1

To add to Martin Konecny's answer. You probably want to use an internal range for everything and convert between chr and ord.

class crange:
    def __init__(self, *args, **kwargs):
        args = [ord(arg) for arg in args]
        kwargs = {key: ord(val) for key, val in kwargs.items()}
        self.range = range(*args, **kwargs)

    def __iter__(self):
        for n in self.range:
            yield chr(n)

    def __contains__(self, c):
        return ord(c) in self.range

    def __getitem__(self, i):
        if isinstance(i, slice):
            ret = crange('\x00')
            ret.range = self.range[i]
            return ret
        else:
            return chr(self.range[i])

    def __repr__(self):
        return  "crange({}, {})".format(
            repr(chr(self.range.start)), repr(chr(self.range.stop)))

r = crange('a', 'f')
print(list(r))
print('b' in r)
print('f' in r)
print(r[:2])

In other words: if we can't subclass it we can use object composition.