FOR WHILE LOOP Question

Question

Firstly below my code (that works):

def power(num,power):
j=0
while j <=power:
for i in range(power):
res=num**i
print(str(num) + " at " + str(i) + " = " + str(res) )
j+=1
return res
power(2,5)

But, if I DON'T insert "return res" at the end, it repeats the output twice.
Why?
Thanks

Answer 1

at the end of for loop j is 5.
and condition j<=5 (j is less than or equal to 5) is still true. use j<power instead

Answer 2

when it return the function end, also the loops inside the function.
when return is removed, the loop executed again because the condition of the while loop still true.

Answer 3

This is what I don't understand: if there is a "while j<=power" I expect the loop to stop when j=5 (so my last power is 4).
After that, it should stop! But clearly I miss something....

Answer 4

Ok thanks Taste now I realize my mistake. I was looking at "i" while indeed I was not paying attention to "j". Anyway you helped me to wake up! Thanks