带有列表理解的python三元迭代
问题描述
可以进行三元迭代吗?我的意思的简化版本,虽然这个特定的例子可以用更好的方式完成:
Is ternary iteration possible? A simplistic version of what I mean, though this particular example could be done in a better way:
c = 0
list1 = [4, 6, 7, 3, 4, 5, 3, 4]
c += 1 if 4 == i for i in list1 else 0
一个更实际的例子:
strList = ['Ulis', 'Tolus', 'Utah', 'Ralf', 'Chair']
counter = 0
counter += 1 if True == i.startswith('U') for i in strList else 0
return counter
解决方案
你的实际例子"写成:
>>> strList = ['Ulis', 'Tolus', 'Utah', 'Ralf', 'Chair']
>>> sum(1 for el in strList if el.startswith('U'))
2
你的另一个例子(如果我理解正确的话)是:
Your other example (if I understand correctly) is:
>>> list1 = [4, 6, 7, 3, 4, 5, 3, 4]
>>> list1.count(4)
3
(或者只是改编 strList
示例,但使用内置方法没有错)
(or just adapt the strList
example, but nothing wrong with using builtin methods)
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