函数默认值初始化引起的问题
妙音
posted @ 2018年3月30日 17:58
in python
, 1291 阅读
函数的默认值只会创建一次，之后不会再变了，使用对象(列表、字典、实例)作为默认值，会导致函数混乱
- 官方说明
- 示例
def f(a, L=[]):
L.append(a)
return L
for i in range(3):
print f(i)
#输出
[0]
[0, 1]
[0, 1, 2]
- 规避方法
def f(a, t=None):
t = t or []
t.append(a)
return t
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