如何比較重複項目列表（含有N項），但僅限於不同列表中的項目

Question

經過幾年的關注，我回到了編程階段，並且在繞過這個問題時遇到了麻煩。用戶定義的分類設定量但RasterValue是列表是長度N

示例： ClassificationSet =（1，2，3，4，5，6）由用戶#define的
RasterVal =（）＃長度= N

我存儲物品進入RasterVal使用ClassificationSet作爲指標： RasterVal（ClassificationSet）。新增（導入值）

RasterVal(1) = 22,23,24,25,23,23,22 
RasterVal(2) = 22,30,31,32,30,30 
RasterVal(3) = 31 

它是：RasterVal（[]，[22,23,24 ，25,23,23,22]，[22,30,31,32,30,30]，[31]）

我想列出重複的值，但只有當它們在不同的集合中重複時纔是重複的，而不是相同的。

輸出應該是： RepeatSet = 22，31

非常感謝您的任何幫助。我已經能夠比較這些集合，但是它列出了重複的值，即使它們出現在相同的集合列表中。

Answer 1

@lukecampbell是正確的：

>>> lsts = [[22,23,24,25,23,23,22],[22,30,31,32,30,30],[31]] 
>>> from collections import Counter 
>>> c = Counter(x for lst in lsts for x in set(lst)) 
>>> [x for x,y in c.items() if y > 1] 
[22, 31] 

該算法的運行時間是線性的，而不是在組數二次的。

Answer 2

#-- Your initial data... 
rasterVals = [ 
    (22,23,24,25,23,23,22), 
    (22,30,31,32,30,30), 
    (31,) 
] 

#-- This will be a set, which holds only distinct values. 
repeated = set() 

#-- We set up a classic inner-outer loop to iterate over all 
#-- pairs of lists in your given data. (Note, there are better ways 
#-- of doing this in Python, but this is the easiest to read and understand) 
for a in rasterVals: 
    #-- First, we'll make a set from the first element. 
    #-- Since sets only hold distinct values, any repeated numbers 
    #-- in the sequence will be ignored. 
    s = set(a) 

    for b in rasterVals: 
     #-- Test that we are not comparing a sequence to itself. 
     if (a is not b): 
      #-- Make a set for the inner loop. (again, only distinct numbers...) 
      t = set(b) 

      #-- Get the intersection of s and t, answering with only those elements 
      #-- that are in both s and t. 
      intersecting = (s & t) 

      #-- We update our set of (inter-sequence) repeated elements. 
      repeated.update(intersecting) 

#-- Show the results. 
print repeated 

Answer 3

RasterVal = [[22,23,24,25,23,23,22],[22,30,31,32,30,30],[31]] 

from itertools import combinations 
out = set() 
for a,b in combinations(RasterVal,2): 
    out = out|(set(a)&set(b)) 

print out 
#output: 
set([22, 31])