data = [1,5,-3,-2,8,0,9]
res = []
for x in data:
if x >=0:
res.append(x)
print(res)
filter(lambda x:x>=0,data)
from random import randint data = [randint(-10,10) for x in range(10)] a = filter(lambda x:x>=0,data) print(data) #在python3中需要list(a)这一步,python2不需要这步 # 原因是在python3中,map函数仅仅是创建一个待运行的命令容器 # 只有其他函数调用它的时候才返回结果 print(list(a))
[x for x in data if x>=0]
,推荐使用列表解析data = [1,5,-3,-2,8,0,9] a = [x for x in data if x>=0] print(list(a))
{k:v for k,v in d.items() if v>90}
,python2用d.iteritems()
from random import randint
d = {x : randint(60,100) for x in range(1,21)}
print(d)
dict = {k:v for k,v in d.items() if v>90}
print(dict)
{x for x in s if x%3==0}
from random import randint
data = [randint(-10,10) for x in range(10)]
print(data)
s = {x for x in data if x % 3 ==0}
print(s)