Python Common errors

1, single element tuple (1,) instead of (1)

2. Copy of List

>>> mylist=[1,2]>>> mylist2=mylist>>> mylist3=list (mylist) >>> mylist2[1]=3>>> mylist2[1, 3]>>> mylist[1, 3] >>> mylist3[1, 2]

It is obvious here that Mylist2 is just a reference to mylist, so modifying the mylist2 is actually modifying the MyList

Mylist3 is a new copy.

#浅拷贝概念
>>> mylist=[1,[1,2]>>> mylist2=list (mylist)>>> mylist2[1, [ 1, 2]]>>> mylist2[1][1]=5>>> mylist2[1, [1, 5]]>>> mylist[ 1, [1, 5]]

>>> mylist2[1]=[1,2,3]
>>> MyList
[1, [1, 5]]
>>> Mylist2
[1, [1, 2, 3]]

Here there is a shallow copy involved, because Mylist2[1] is just a shallow copying, only copy the reference does not copy the value

But if you re-assign the value to Mylist2[1, then there's no problem.

Python Common errors