how to find last index of list in python

# Use an Index of -1
l = [1,2,3,4]
print(l[-1])
# Returns 4

def list_rindex(li, x):
    for i in reversed(range(len(li))):
        if li[i] == x:
            return i
    raise ValueError("{} is not in list".format(x))

# using rindex() 
test_string = "abcabcabc"
# using rindex() 
# to get last element occurrence 
res = test_string.rindex('c')  
# printing result 
print ("The index of last element occurrence: " + str(res))

OUTPUT:
  The index of last element occurrence: 8