If I want to get the value when the last loop completed,I can use last_a=a

But how to get the value when the first 2 loops are completed

Input:

A=[20,13,15,25,24,17,14,19,23,11]
B=[32,43,65,21,13,16,53,52,35,38]
last_a=last_b=0
last_last_a=0
last_last_b=0
for a,b in zip(A, B):
    if a<last_a and b<last_b:
        pass
    last_a=a
    last_b=b
    print(last_last_a)

Expected Output

0
0
20
13
15
25
24
17
14
19

CodePudding user response：

You need to add last_last_a = last_a before assigning to last_a. Also, you need to print before making those assignments, as these assignments serve for the next iteration of the loop. So:

for a,b in zip(A, B):
    if a<last_a and b<last_b:
        pass
    print(last_last_a)    # moved up
    last_last_a = last_a  # <-- added
    last_a=a
    last_b=b

As you don't print last_last_b, there is no need for that name.

CodePudding user response：

You can use enumerate with zip to keep track.

And then just use required index.

for index, (name, age) in enumerate(zip(names, ages)):
...

CodePudding user response：

If you want to output the value after two loops, just track the loops with a variable like i. However, if you want a value

after the first 2 loops are completed

you will not get a list as written in expected Output but one value (or more if you add print statements). I think your logic is off, since last_last_a is never modified.

A=[20,13,15,25,24,17,14,19,23,11]
B=[32,43,65,21,13,16,53,52,35,38]
last_a=last_b=0
last_last_a=0
last_last_b=0
for i, (a,b) in enumerate(zip(A, B)):
    if a<last_a and b<last_b:
        pass
    last_a=a
    last_b=b
    if i==2:
        print(last_last_a)