list_comprehension.py

# first list
a = [1, 2, 3, 4]

# second list
b = ['a', 'b']

# expected list
exp = ['a1', 'a2', 'a3', 'a4', 'b1', 'b2', 'b3', 'b4']

# WITHOUT list comprehension
result = []
for item_a in a:
    for item_b in b:
        result.append(item_b+str(item_a))

print('without', result)

# WITH list comprehension
result = [item_b+str(item_a) for item_a in a for item_b in b]

print('with', result)