32 lines
900 B
Python
32 lines
900 B
Python
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import math
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from functools import partial
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# 假设我们有这样一个函数
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def spam(a, b, c, d):
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print(a, b, c, d)
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if __name__ == '__main__':
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# 这个函数的输入参数有一大堆,但是其中几个是固定的,那就有用了
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s1 = partial(spam, 1) #固定a=1
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s2 = partial(spam, d=2) # 固定d=2
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s3 = partial(spam, 3, 3, d=3) # 固定a=3 b=3 d=3
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s1(2,3,4)
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s2(1,2,3)
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s3(1)
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# partial返回的是一个被填充了部分参数的函数,参数数量等于被包装的函数的剩余参数个数
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# 这个函数可以用来适配一些参数数量受限的复用场景, 比如sorted函数的key参数仅支持单参数函数
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points = [(1, 2), (3, 4), (5, 6), (7, 8)]
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def dis (p1, p2):
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x1, y1 = p1
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x2, y2 = p2
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return math.hypot(x2-x1, y2-y1)
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pt = (4, 3)
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s = partial(dis, pt)
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print(sorted(points, key=s))
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