Python输出说明

Question

I came across a piece of python code, requiring me to give the output. The code goes as follows:

a = [1, 2]
b = [a, 3]
c = b[:]
a[0] = 7
b[1] = 8
print c

I thought the output to be [[7, 2], 8] since i have the reference to the a in b , and consequently, c had the reference to b

But the output came out to be [[7, 2], 3]

What am I missing here?

Answer 1

c had the reference to b

This is where you went wrong. c is initialized as a (shallow) copy of b .

If it were simply c = b (without the [:] ) then you'd be correct.