split

gistfile1.txt

class split:
    def __init__(self, delimiter, sequence):
        """
        Break a sequence on particular elements.
        Return an iterator over chunks.

        Arguments:

        delimiter   if a function, it returns True on chunk separators;
                    otherwise, it is the value of chunk separator.
        sequence    original sequence;
        keepdelims  whether or not to keep delimiters in chunks

        """
        self.delimiter = delimiter(x) if callable(delimiter) else partial(eq, delimiter)
        self.sequence = iter(sequence)
        self.active = OrderedDict()
        self.id = 0
        self.last_yielded_subgen_id = 0

    def __iter__(self):
        return self

    def subgen(self, id, item, buffered):
        if self.delimiter(item):
            return
        yield item
        buffered = self.active[id][1]
        while True:
            if buffered:
                yield from (buffered.popleft() for i in range(len(buffered)))
            elif id not in self.active:
                return
            else:
                try:
                    item = next(seq)
                except StopIteration:
                    self.active.pop(id)
                    return
                else:
                    is_delim = self.delimiter(item)
                    if is_delim:
                        if self.active:
                            self.active.popitem(last=False)
                    else:
                        if self.active:
                            self.active[0][1].append(item)
                        else:
                            yield item

    def __next__(self):
        if self.active:
            yield self.active[min(self.active)][0]
        else:
            try:
                item = next(self.sequence)
            except StopIteration:
                return
            else:
                buffer = deque()
                self.id += 1
                subg = self.subgen(id, item, buffer)
                self.active[id] = subg, buffer
                yield subg