python求两个列表的并集.交集.差集

求两个列表的差集

>>> a = [1,2,3]

>>> b=[1,2]

>>> ####################################

>>> #两个列表的差集

>>> ret = []

>>> for i in a:

    if i not in b:

         ret.append(i)

>>> ret

[3]

>>> #两个列表的差集2

>>> ret2 = [ i for i in a if i not in b ]

>>> ret2

[3]

>>> #两个列表的差集3

>>> ret3 = list(set(a) ^ set(b))

>>> ret3

[3]

>>> #两个列表的差集4

>>> ret4=list(set(a).difference(set(b))) #  b中有而a中没有的

>>> ret4

[3]

求两个列表的并集

>>> ########################################

>>> #获取两个list 的并集

>>> ret1=list(set(a).union(set(b)))

>>> ret1

[1, 2, 3]

>>> ret1=list(set(a).union(set([4,5,6])))

>>> ret1

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

>>> #获取两个list 的并集2

>>> ret2= list(set(a) | set(b))

>>> ret2

[1, 2, 3]

>>> ret2=list(set(a)-set(b))#####差集

>>> ret2

[3]

求两个列表的交集

>>> ##########################################

>>> #获取两个列表的交集

>>> a = [1, 2, 3, 4, 5, 6]

>>> b = [2, 4, 6, 8 ,10]

>>> ret1= [x for x in b if x in set(a)]   # list a is the larger list b

>>> ret1

[2, 4, 6]

>>> #获取两个列表的交集2

>>> ret2= list(set(a) & set(b))

>>> ret2

[2, 4, 6]

>>> #获取两个列表的交集3

>>> ret3= list(set(a).intersection(b))

>>> ret3

[2, 4, 6]

>>>  #获取两个列表的交集4

>>> ret4 = list((set(a).union(set(b)))^(set(a)^set(b)))

>>> ret4

[2, 4, 6]

>>>

转自:https://blog.csdn.net/manjhok/article/details/79584110