Python：对列表副本进行切片会在使用嵌套的for循环时影响原始的元组或列表

Question

I'm having trouble changing any list copies of a list or tuple. When using two nested For loops the tuple is changed, as below:

testInput = ( ['foo','foo',], ['foo','foo'] )
testCopy = list(testInput)

for rowIndex, row in enumerate(testCopy):
    for columnIndex, column in enumerate(row):
        testCopy[rowIndex][columnIndex] = ['bar']

print(testInput)
print(testCopy)

>>>([['bar'], ['bar']], [['bar'], ['bar']])
>>>[[['bar'], ['bar']], [['bar'], ['bar']]]

when only using one for loop is used, it works as I expect it to and only changes the copy:

for rowIndex, row in enumerate(testCopy):
    testCopy[rowIndex] = ['bar']

>>>([['foo'], ['foo']], [['foo'], ['foo']])
>>>[['bar'], ['bar']]

this happens regardless of if the original is a list or tuple or however the copy is formatted:

testCopy = testInput
testCopy = list(testInput)
testCopy = testInput[:]

Answer 1

Nested list copy with recursive function: This way the copy is a copy not related with the original

def copyList(yourList):   
    yourCopiedList=[]   
    for listElement in yourList:
    if type(listElement)==list:
      yourCopiedList.append(copyList(listElement.copy()))
    else:
      yourCopiedList.append(listElement)   
    return yourCopiedList