Python列表、字典与集合数据筛选实战：普通循环、Filter与解析式对比

#!/usr/bin/python3
 
 
def filter_l(data):
 res = []
 for i in data:
  if i > 0:
   res.append(i)
 return res
 
if __name__ == '__main__':
 data = [3, 9, -1, 10, -2]
 new_l = filter_l(data)
 print(new_l)

#!/usr/bin/python3
 
from random import randint
 
 
def filter_l(data):
 # 循环data列表，把值一个一个取出 交个lambda中x，如何lambda函数为True，返回x生成一个新的filter对象
 return filter(lambda x: x >= 0, data)
 
if __name__ == '__main__':
 # 列表生成10个 -10 到 10 的随机数
 data = [randint(-10, 10) for _ in range(10)]
 print(data)
 # new_l 为可迭代对象
 new_l = filter_l(data)
 print(list(new_l), type(new_l))

#!/usr/bin/python3
 
from random import randint
 
 
def filter_l(data):
 # 循环data列表，把值一个一个取出 是否满足if条件，满足True返回x生成一个新列表
 return [x for x in data if x >=0 ]
 
if __name__ == '__main__':
 # 列表生成10个 -10 到 10 的随机数
 data = [randint(-10, 10) for _ in range(10)]
 print(data)
 # new_l 为可迭代对象
 new_l = filter_l(data)
 print(list(new_l), type(new_l))

#!/usr/bin/python3
 
from random import randint
 
 
def filter_l(data):
 print(data.items())
 # 把字典转换成dict_items，循环里面的key和value，满足if条件返回对应的key和value值
 return {k: v for k, v in data.items() if v > 90}
 
if __name__ == '__main__':
 # 字典生成式
 data = {x: randint(0, 100) for x in range(10)}
 print(data)
 new_l = filter_l(data)
 print(new_l, type(new_l))

#!/usr/bin/python3
from random import randint
 
 
def filter_l(data):
 # 迭代集合中值，满足条件为True返回x
 return {x for x in data if x % 3 == 0}
 
if __name__ == '__main__':
 # 集合生成式
 data = {randint(0, 100) for x in range(10)}
 print(data)
 new_l = filter_l(data)
 print(new_l, type(new_l))