How do I set limits for my range function in python?

Issue

Say I am iterating through a list. I want to check if the list’s neighbours (i-1 and i+1) contain a certain element. How do I do this without running into "list index out of range" problem?
Example:

list = [1, 0, 1, 0, 1, 0]
for i, j in enumerate(list):
    elements = 0
    for m in range(i-1,i+2):
        if list[m] == 1:
            elements += 1
    print(list[i], elements)

How do I set boundaries for the range function, so that it doesn’t go below 0 and above len(list)?

Solution

If you want to iterate for all elements in the target list, one solution is to check the value of second for loop:

_list = [1, 0, 1, 0, 1, 0]
elements = 0
for i, j in enumerate(_list):
    for m in range(max(i-1, 0), min(i+2, len(_list))):
        if _list[m] == 1:
            elements += 1

Answered By – Hayoung

Answer Checked By – Gilberto Lyons (AngularFixing Admin)