在Python中高效地搜索字符串列表中的字符串列表

我有一个字符串列表和一个字符串列表。例如：

L1=[["cat","dog","apple"],["orange","green","red"]]
L2=["cat","red"]

如果 L1[i] 包含 L2 中的任何项目，我需要放置这些对（用于在图中创建边） 就像，在我的例子中，我需要这些对("cat","dog"),("cat,apple"),("red,orange"),("red","green")

我应该使用什么方法才能最有效。 （我的 L1 列表很大）

假设您的 L1 子列表中可能有多个“控制”项。

我会用set() http://docs.python.org/py3k/library/stdtypes.html#set-types-set-frozenset and itertools.product() http://docs.python.org/py3k/library/itertools.html#itertools.product:

from itertools import product

def generate_edges(iterable, control):
    edges = []
    control_set = set(control)
    for e in iterable:
        e_set = set(e)
        common = e_set & control_set
        to_pair = e_set - common
        edges.extend(product(to_pair, common))
    return edges

Example:

>>> L1 = [["cat","dog","apple"],
...       ["orange","green","red"],
...       ["hand","cat","red"]]
>>> L2 = ["cat","red"]
>>> generate_edges(L1, L2)
[('apple', 'cat'),
 ('dog', 'cat'),
 ('orange', 'red'),
 ('green', 'red'),
 ('hand', 'red'),
 ('hand', 'cat')]