python 列表list去重

python 列表list去重

 

一.{}.fromkeys(list).keys()

list2 = {}.fromkeys(list1).keys()

list2 = {}.fromkeys(list1).keys()

(set(list1))

 

三.itertools.grouby

ids = [1,4,3,3,4,2,3,4,5,6,1]

ids.sort()

it = itertools.groupby(ids)

 for k, g in it:

    print k

 

四,笨方法

 

四,笨方法

ids =3,2,3333,333, ,5,6,1]

news_ids = []

for id in ids:

    if id not in news_ids:

        news_ids.append(id)

print news_ids

這四種都有個特點，去重後元素排序變了，效率據說第一種比第二種快一點

 

五.索引再次排序這種可以去重並且保持元素順序

#要結果是[1, 4, 3, 2, 5, 6]  不要[1, 2, 3, 4, 5, 6]

ids = [1,4,3,3,4,2,3,4,5,6,1]

news_ids = list(set(ids))

news_ids.sort(key=ids.index)

print news_ids #[1, 4, 3, 2, 5, 6]

 

。 1,4,3,3,4,2,3,4,5,6,1]

func = lambda x,y:x if y in x else x + [y]

print reduce(func, [ [], ] + ids)#[1, 4, 3, 2, 5, 6]

🎜