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yellowtail
V2EX  ›  Python

闭包练习,为什么第一个写法和第二个学法输出不一样?

  •  
  •   yellowtail · Jul 7, 2021 via iPhone · 1853 views
    This topic created in 1774 days ago, the information mentioned may be changed or developed.
    def fapi(i):
    def fuc():
    return i**2
    return fuc

    l=[]
    for i in range(4):
    l.append(fapi(i))
    l[0]()

    def mainf():
    l = []
    for i in range(4):
    def f():
    return i**2
    l.append(f)
    return l

    mainf()[0]()

    def mainf2():
    l = []
    def f():
    return i**2
    for i in range(4):
    l.append(f)
    return l

    mainf2()[0]()
    3 replies    2021-07-12 11:46:12 +08:00
    frostming
        1
    frostming  
       Jul 8, 2021
    缩进全丢了让人怎么看?

    mainf 和 mainf2 效果是完全一样的,闭包内的自由变量直到包装的函数被调用时才会真正去寻值,i 都等于 3
    yellowtail
        2
    yellowtail  
    OP
       Jul 10, 2021
    @frostming 手机发帖不习惯,想了下没有缩减也不会有歧义,抱歉...不过第一个也都是对应的 i,结束以后应该都是 9 。
    frostming
        3
    frostming  
       Jul 12, 2021
    第一个是正常输出 0,建议你重试下
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