Two lines needlessly used in else statement. Help shorten it

Question

#verifying my shopping list
i=input()
shopping=['tomato', 'potato', 'onion']
j=2
if i in shopping:
print('its there')
#remove duplication in next two line
else: shopping+=[j+1]
shopping [j+1]=i
print(shopping)

Answer 1

#you can do this:
shopping.append(i)

#however, that's asuuming you don't want shopping+=[j+1] , I don't know why you'd want to add the number three to it...

Answer 2

thank you, I seem to have forgotten why I couldn't think of append or insert commant