Question about iterating through a irritable loop resulting in index out of range-CodePudding

This works just fine

list_a = [1,2,3,4,5,6,7,8,9,10]

for i in list_a:
    for h in range(1,list_a[i]):
        print(h)

but this does not work

months_b = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

for i in months_b:
    for h in range(1,months_b[i]):
        print(h)

getting error

"for h in range(1,months_b[i]):"

"IndexError: list index out of range"

CodePudding user response：

On your first pass through the loop with months_b your variable i is set to the first value of the list, so 31. Then you iterate over the list from index 1 to 31 and there are not 31 elements of the list. Therefore, index out of range.

CodePudding user response：

forvariableiniterable iterates over elements, not indices.

You want to use something like this:

for month in months:
    for h in range(1,month):
        print(h)

CodePudding user response：

range is a list of natural numbers, in your case starting from 1 until months_b[i]. Since your for loop iterates over the elements of months_b, your first i will be 31. Therefore, your second loop will try to access the 31th element of months_b, which is out of range.