[英]intersection of three sets in python?
Currently I am stuck trying to find the intersection of three sets. 目前我被困在试图找到三组的交集。 Now these sets are really lists that I am converting into sets, and then trying to find the intersection of.
现在这些集合实际上是我要转换成集合的列表,然后尝试找到它的交集。
Here's what I have so far: 这是我到目前为止所拥有的:
for list1 in masterlist:
list1 = thingList1
for list2 in masterlist:
list2 = thingList2
for list3 in masterlist:
list3 = thingList3
d3 = [set(thingList1), set(thingList2), set(thingList3)]
setmatches c = set.intersection(*map(set,d3))
print setmatches
and I'm getting 而且我正在
set([])
Script terminated.
I know there's a much simpler and better way to do this, but I can't find one... 我知道有一个更简单,更好的方法来做到这一点,但我找不到一个......
EDIT 编辑
Okay, here's what I have now. 好的,这就是我现在所拥有的。
setList=()
setList2=()
setList3=()
for list1 in masterlist:
setList=list1
for list2 in masterlist:
setList2=list2
for list3 in masterlist:
setList3=list3
setmatches=set(setList) & set(setList2) & set(setList3)
print setmatches
Still doesn't give me what I'm looking for: which is the one match I ensured was in each list. 仍然没有给我我正在寻找的东西:这是我确保在每个列表中的一个匹配。 It's giving me what looks like an addition of all the sets.
它给了我看起来像是所有套装的补充。
I think you are simply looking for: 我想你只是在寻找:
set(thingList1) & set(thingList2) & set(thingList3)
The ampersand is intersection in Python (and some other languages as well). &符是Python(以及其他一些语言)的交集。
set1 & set2 & set3
should work ... at least I think 应该工作......至少我认为
>>> set((1,2,3)) & set((2,3,4)) & set((3,4,5))
set([3])
你需要这样的东西:
frozenset(list1) & frozenset(list2) & frozenset(list1)
这应该做的伎俩:
reduce(lambda x,y: x&y, mysetlist)
A list of sets, you say? 你说的套装清单?
In [1]: mylist = [ [1, 2, 3, 4], [3, 4, 5, 6, 7], [2, 3, 4, 5, 6] ]
In [2]: result = set(mylist[0])
In [3]: for item in mylist:
...: result = result.intersection(item)
...:
...:
In [4]: result
Out[4]: set([3, 4])
set.intersection(*map(set,d3))
Will actually work, though because d3
already contains sets you can just do: 将实际工作,但因为
d3
已经包含集,你可以这样做:
set.intersection(*d3)
And, in fact, only the first one needs to be a set
- the others can be any iterable, and intersection
will setify them by itself. 而且,事实上,只有第一个需要成为一个
set
- 其他可以是任何可迭代的, intersection
将自己整理它们。
The problem you're having doesn't seem to be in this code - rather, 您遇到的问题似乎不在此代码中 - 相反,
for list1 in masterlist:
list1 = thingList1
Won't actually put anything into thingList1
. 实际上不会将任何东西放入
thingList1
。 It is hard to tell without seeing what masterlist
looks like, but you may want something like: 没有看到什么样的
masterlist
看起来很难说,但你可能需要这样的东西:
for list1 in masterlist:
thingList1[:] = list1
print
your three lists before you do the intersection to make sure they contain what you expect. 在做交叉点之前
print
三个列表以确保它们包含您期望的内容。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.