37 lines
1.3 KiB
Python
37 lines
1.3 KiB
Python
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# collection库中有一个东西叫做namedtuple,有点像结构体,可以给元组中的元素起名
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from collections import namedtuple
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Subscribe = namedtuple('Subscriber', ["addr", "joined"])
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sub = Subscribe("suka@qq.com", "2024/07/17")
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print(sub)
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print(sub.addr)
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print(sub.joined)
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# 可以看到,这个东西和对象有点相似,但这种操作又保留了适用于元组的所有操作,比如索引和分解
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print(sub[0])
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print(len(sub))
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addr, joined = sub
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print(addr, joined)
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# 如果我们获取的数据总是list类型,不是标准的json数据,那这东西就很有用
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# 比如返回的数据是这种东西: data = [0,1,1,3,2,6]
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# 如果是这种非标数据,普通代码处理长这样:
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def compute_cost(records):
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total = 0.0
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for rec in records:
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total += rec[1] * rec[2]
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return total
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# 这造成一个问题,鬼知道rec[1]和rec[2]是什么东西,代码可读性很傻逼;
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# 所以我们可以在拿到数据的时候先标准化一下
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Stock = namedtuple("Stock", ['name', 'share', 'price'])
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def compute_cost(records):
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total = 0.0
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for rec in records:
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stock = Stock(*rec)
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total += stock.share * stock.price
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return total
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# 当然如果返回的已经是对象了,那就没有做namedtuple的必要了,在不想用类的时候可以用这东西替代字典
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