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  2. Python Language 教程
  3. 功能

功能

Created: November-22, 2018

你可以用功能做的 5 件基本事情：

  • 將函式分配給變數

    def f():
  print(20)
y = f
y()
# Output: 20

  • 在其他函式中定義函式（ 巢狀函式 ）

    def f(a, b, y):
    def inner_add(a, b):      # inner_add is hidden from outer code
        return a + b
    return inner_add(a, b)**y

  • 函式可以返回其他函式

    def f(y):
    def nth_power(x):
        return x ** y
    return nth_power    # returns a function

squareOf = f(2)         # function that returns the square of a number           
cubeOf = f(3)           # function that returns the cube of a number
squareOf(3)             # Output: 9
cubeOf(2)               # Output: 8

  • 函式可以作為引數傳遞給其他函式

    def a(x, y):
    print(x, y)
def b(fun, str):        # b has two arguments: a function and a string 
    fun('Hello', str)
b(a, 'Sophia')           # Output: Hello Sophia

  • 內部函式可以訪問封閉範圍（ Closure ）

    def outer_fun(name):
    def inner_fun():     # the variable name is available to the inner function
        return "Hello "+ name + "!"
    return inner_fun
greet = outer_fun("Sophia")
print(greet())            # Output: Hello Sophia!

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