作用域（全局变量和局部变量）

作用域

>>> x = 1 >>> scope = vars() >>> scope['x'] 1 >>> scope['x'] += 1 >>> x 2

警告　

>>> def foo(): x = 42 ... >>> x = 1 >>> foo() >>> x 1

>>> def output(x): print(x) ... >>> x = 1 >>> y = 2 >>> output(y) 2

>>> def combine(parameter): print(parameter + external) ... >>> external = 'berry' >>> combine('Shrub') Shrubberry

警告　

“遮盖”的问题

>>> def combine(parameter): ...     print(parameter + globals()['parameter']) ... >>> parameter = 'berry' >>> combine('Shrub') Shrubberry

重新关联

>>> x = 1 >>> def change_global(): ...     global x ...     x = x + 1 ... >>> change_global() >>> x 2

def foo():     def bar():         print("Hello, world!")     bar()

def multiplier(factor):     def multiplyByFactor(number):         return number * factor     return multiplyByFactor

def multiplier(factor):     def multiplyByFactor(number):         return number * factor     return multiplyByFactor  >>> double = multiplier(2) >>> double(5) 10 >>> triple = multiplier(3) >>> triple(3) 9 >>> multiplier(5)(4) 20