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[英]Fastest way of checking if two lists have at least 2 common items in Python?
[英]Fastest way to compare common items in two lists
我有兩個這樣的列表:
listt = [["a","abc","zzz","xxx","abc","abc"],["yyy","ggg","abc","cccc"]]
我有另一個這樣的查詢列表:
queryList = ["abc","cccc","abc","yyy"]
queryList
& listt[0]
共有 2 個"abc"
。
queryList
和listt[1]
共有 1 個"abc"
, 1 個"cccc"
和 1 個"yyy"
。
所以我想要一個像這樣的 output :
[2,3] #2 = Total common items between queryList & listt[0]
#3 = Total common items between queryList & listt[1]
我目前正在使用循環來執行此操作,但這似乎很慢。 我將有數百萬個列表,每個列表有數千個項目。
listt = [["a","abc","zzz","xxx","abc","abc"],["yyy","ggg","abc","cccc"]]
queryList = ["abc","cccc","abc","yyy"]
totalMatch = []
for hashtree in listt:
matches = 0
tempQueryHash = queryList.copy()
for hash in hashtree:
for i in range(len(tempQueryHash)):
if tempQueryHash[i]==hash:
matches +=1
tempQueryHash[i] = "" #Don't Match the same block twice.
break
totalMatch.append(matches)
print(totalMatch)
好吧,我仍在學習 Python 中的技巧。 但是根據這個較早的帖子,應該可以使用以下內容:
from collections import Counter
listt = [["a","abc","zzz","xxx","abc","abc"],["yyy","ggg","abc","cccc"]]
queryList = ["abc","cccc","abc","yyy"]
OutputList = [len(list((Counter(x) & Counter(queryList)).elements())) for x in listt]
# [2, 3]
我會留意其他方法...
JvdV答案的改進。
基本上對值求和而不是對元素進行計數,並且還緩存 queryListCounter。
from collections import Counter
listt = [["a","abc","zzz","xxx","abc","abc"],["yyy","ggg","abc","cccc"]]
queryList = ["abc","cccc","abc","yyy"]
queryListCounter = Counter(queryList)
OutputList = [sum((Counter(x) & queryListCounter).values()) for x in listt]
您可以列出 listt 和 queryList 的匹配項並計算匹配的數量。
output = ([i == z for i in listt[1] for z in queryList])
print(output.count(True))
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