python - Accessing the index in 'for' loops

#short
#python
#loops
#list
How do I access the index while iterating over a sequence with a for loop?
xs = [8, 23, 45]

for x in xs:
print("item #{} = {}".format(index, x))

Desired output:
item #1 = 8
item #2 = 23
item #3 = 45