Method split

sorts/external-sort.py:25–40

(self, block_size, sort_key=None)

        return self.block_filenames

    def split(self, block_size, sort_key=None):
        i = 0
        with open(self.filename) as file:
            while True:
                lines = file.readlines(block_size)

                if lines == []:
                    break

                if sort_key is None:
                    lines.sort()
                else:
                    lines.sort(key=sort_key)

                self.write_block(''.join(lines), i)
                i += 1

    def cleanup(self):
        map(lambda f: os.remove(f), self.block_filenames)