Python：獲取列表中最常見的項目

Question

我有一個元組列表，我想獲取最頻繁出現的元組，但是如果有「聯合獲勝者」，它應該隨機選擇它們。

tups = [ (1,2), (3,4), (5,6), (1,2), (3,4) ] 

所以我想要的東西，會在回報（1,2）或隨機對以上列舉

Answer 1

您可以先使用Counter來查找最重複的元組。然後找到所需的元組並最終隨機獲得第一個值。

from collections import Counter 
import random 

tups = [ (1,2), (3,4), (5,6), (1,2), (3,4) ] 
lst = Counter(tups).most_common() 
highest_count = max([i[1] for i in lst]) 
values = [i[0] for i in lst if i[1] == highest_count] 
random.shuffle(values) 
print values[0] 

Answer 2

（3,4）你可以先排序列表以獲得通過頻率排序的元組。之後，線性掃描可以從列表中獲得最頻繁的元組。總體時間O(nlogn)

>>> tups = [ (1,2), (3,4), (5,6), (1,2), (3,4) ] 
>>> 
>>> sorted(tups) 
[(1, 2), (1, 2), (3, 4), (3, 4), (5, 6)] 

Answer 3

使用collections.Counter：

>>> collections.Counter([ (1,2), (3,4), (5,6), (1,2), (3,4) ]).most_common()[0] 
((1, 2), 2) 

這是O(n log(n))。

Answer 4

這一個應該做你的任務在o(n)時間：

>>> from random import shuffle 
>>> from collections import Counter 
>>> 
>>> tups = [(1,2), (3,4), (5,6), (1,2), (3,4)] 
>>> c = Counter(tups)       # count frequencies 
>>> m = max(v for _, v in c.iteritems())   # get max frq 
>>> r = [k for k, v in c.iteritems() if v == m] # all items with highest frq 
>>> shuffle(r)         # if you really need random - shuffle 
>>> print r[0] 
(3, 4) 

Answer 5

最常見的collections.Counter，然後隨機選擇計數：

import collections 
import random 

lis = [ (1,2), (3,4), (5,6), (1,2), (3,4) ] # Test data 
cmn = collections.Counter(lis).most_common() # Numbering based on occurrence 
most = [e for e in cmn if (e[1] == cmn[0][1])] # List of those most common 
print(random.choice(most)[0]) # Print one of the most common at random