Common prefix, suffix and two-sided compression

prefix_suffix_compress.py

def common_prefix(strings):
    def _iter():
        for z in zip(*strings):
            if z.count(z[0]) == len(z):  # check all elements in `z` are the same
                yield z[0]
            else:
                return

    return "".join(_iter())

def common_suffix(strings):
    def _iter():
        for z in zip(*(reversed(s) for s in strings)):
            if z.count(z[0]) == len(z):  # check all elements in `z` are the same
                yield z[0]
            else:
                return
    return "".join(reversed(list(_iter())))

def compress(strings, *, group_start="(", group_end=")", sep=","):
    """Given a list of strings, create a single string with prefix and suffix separated".
    I.e. ["A_X_Z", "A_Y_Z"] -> "A_(X,Y)_Z"
    """
    if len(strings) == 1:
        return "".join(strings)
    pre = common_prefix(strings)
    suf = common_suffix(s[len(pre):] for s in strings)
    return pre + group_start + sep.join(s[len(pre):].removesuffix(suf) for s in strings) + group_end + suf