控制函数的参数个数
import hashlib
import sys
def main():
if len(sys.argv) != 2:
sys.exit('Usage: %s file' % sys.argv[0])
filename = sys.argv[1]
m = hashlib.md5()
with open(filename, 'rb') as fp:
while True:
blk = fp.read(4096) # 4KB per block
if not blk: break
m.update(blk)
print m.hexdigest(), filename
if __name__ == '__main__':
main()
控制多个异常exceptions
def is_uuid_like(val):
"""Returns validation of a value as a UUID.
For our purposes, a UUID is a canonical form string:
aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa
"""
try:
return str(uuid.UUID(val)) == val
except (TypeError, ValueError, AttributeError):
return False
