列表、字典、集合的解析

列表解析

生成一个随机列表，筛选出正数

>>> data = [randint(-10,10) for x in range(0,10)]

>>> data

[-8, -1, 9, -3, -3, -4, 7, 8, -3, 1]

>>> [x for x in data if x>0]

[9, 7, 8, 1]

 

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字典解析

假设一个班级20人，随机生成这个班级的成绩字典（百分制）

d = {x: randint(0,100) for x in range(1,21)}

>>> d

{1: 43, 2: 4, 3: 30, 4: 1, 5: 71, 6: 82, 7: 29, 8: 59, 9: 76, 10: 24, 11: 84, 12: 1, 13: 90, 14: 75, 15: 21, 16: 85, 17: 32, 18: 62, 19: 95, 20: 25}

 

现将分数大于等于85的元素提取出来

>>> {k:v for k,v in d.iteritems() if v>=85}

{16: 85, 19: 95, 13: 90}

 

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集合解析

生成一个随机列表，再转化为集合，筛选出能被3整除的数

>>> data = [randint(-10,10) for x in range(0,10)]

>>> data

[-8, -1, 9, -3, -3, -4, 7, 8, -3, 1]

>>> s = set(data)

>>> s

set([1, 7, 8, 9, -8, -4, -3, -1])

>>> {x for x in s if x%3==0}

set([9, -3])