def alternative_names(filename):
"""
相同文件命名方式为 a.jpg a-1.jpg a-2.jpg
:param filename: 文件名
:return:
"""
yield filename
base, ext = os.path.splitext(filename)
yield base + ext
for i in itertools.count(1):
yield base + "-%i" % i + ext
使用：
target_name = next(alt_name
for alt_name in alternative_names(file_path)
if not os.path.exists(alt_name))
