python 由表及里理解 lambda

def multipliers():
    return [lambda x: i * x for i in range(4)]

print([m(2) for m in multipliers()])

# [6, 6, 6, 6]

multipliers内嵌套了一个匿名函数
该匿名函数引用外部非全局变量i
返回该嵌套函数

def multipliers():
    # 添加了一个默认参数i=i
    return [lambda x, i=i: i * x for i in range(4)]

print([m(2) for m in multipliers()])

# [0, 2, 4, 6]