[python] extend 和 append 区别

a = [1, 2, 3]
b = [4, 5, 6]
a.append(b)
print(a)

result : [1, 2, 3, [4, 5, 6]]

a = [1, 2, 3]
b = [4, 5, 6]
a.extend(b)
print(a)

result : [1, 2, 3, 4, 5, 6]