用法
Python的lambda運算式用于構建匿名函式,基本語法是在冒號左邊放原函式的引數,可以有多個引數,用逗號隔開即可;冒號右邊是回傳值,
>>> lambda x,y: (x+y)/2
<function <lambda> at 0x005B33D8>
>>> g = lambda x: 2*x + 1
>>> g(10)
21
實體
可以巧妙利用lambda函式將某些方法構建為函式配合map操作序列,
>>> s = ['am','is','are']
>>> up = lambda x: x.upper()
>>> out = map(up,s)
>>> list(out)
['AM', 'IS', 'ARE']
當然這里只是舉例,顯然上述問題有更優解
>>> s = ['am','is','are']
>>> [x.upper() for x in s]
['AM', 'IS', 'ARE']
注意
復雜函式仍然建議def宣告,用lambda降低代碼可讀性,
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標籤:Python
