python中禁止函数修改列表

 

1、原始函数

def a(x,y):
    while x:
        temp = x.pop()
        print(f"printing model:{temp}")
        y.append(temp)

def b(x):
    print("\nThe following model had been printed!")
    for i in x:
        print(i)

list1 = ["aaa","bbb","ccc"]
list2 = []

a(list1,list2)
b(list2)

printing model:ccc
printing model:bbb
printing model:aaa

The following model had been printed!
ccc
bbb
aaa
>>> list1        ## 原始列表变为空列表
[]
>>> list2
['ccc', 'bbb', 'aaa']

 

2、使用函数副本（列表分片复制）

def a(x,y):
    while x:
        temp = x.pop()
        print(f"printing model:{temp}")
        y.append(temp)

def b(x):
    print("\nThe following model had been printed!")
    for i in x:
        print(i)

list1 = ["aaa","bbb","ccc"]
list2 = []

a(list1[:],list2)
b(list2)

printing model:ccc
printing model:bbb
printing model:aaa

The following model had been printed!
ccc
bbb
aaa
>>> list1      ## 原始列表没有改变
['aaa', 'bbb', 'ccc']
>>> list2
['ccc', 'bbb', 'aaa']