python_list1.py

c = [[]]*3      #[[], [], []]
print(c)
c[0].append(100)
print(c)

print(id(c[0])) #c[0]==c[1]==c[2]
print(id(c[1]))

python_list2.py

d = [list() for i in range(3)]  #[[], [], []] but each element is different
print(d)
d[0].append(100)
print(d)

print(id(d[0]))
print(id(d[1]))

python_list3.py

#A container has a space to store references that can be used to refer to other objects.
a=[1,2,3]
mylist=[]
mylist.append(a)

a=[4,5,6]
mylist.append(a)
print('mylist1-->',mylist)  #兩次append的a, refenece 到不同object id, 

python_list4.py

a=[4,5,6]
mylist2=[]
for i in range(3):
    a[i]+=1  #[4,5,6]-->[5,6,7]
    mylist2.append(a)

print('mylist2-->',mylist2)                       

python_list5.py

mylist3=[]
for i in range(3):
    b=[4,5,6]  # reset b , so b is always a new object
    b[i]+=1
    #print(id(b))
    mylist3.append(b) 

print('mylist3-->',mylist3)