Question

我有一个这样的清单：

 all = [[a,b,c,d],[r,d,g,s],[e,r,a,b],[p,o,i,u]....(more similar items)]

我想了解其中有多少项相同，因此我需要将all[0]与all[1],all[2]...all[(len(all)-1)]进行比较，然后使用all[1]与all[2],all[3]...all[(len(all)-1)]进行比较，然后all[2]与all[3],all[4],...all[(len(all)-1)]

进行比较

我试过这样的事情：

 for i in range(len(all)):
     print len(all[i] & all[i+1]) ##how many identical items shared by all[0] and all[1]
     print len(all[i+1] & all[i+2])

但不知道如何继续，我想得到的结果是：

item1 has 3 same values with item2, 
      has 4 same values with item3,
      has 1 same values with item4....

item2 has 3 same values with item1,
      has 2 same values with item3,
      etc

Answer 1

这里最简单的算法是n ^ 2。只需循环遍历列表两次：

for x, left in enumerate(all):
    for y, right in enumerate(all):
        common = len(set(left) & set(right))
        print "item%s has %s values in common with item%s"%(x, common, y)

Answer 2

设置是要走的路。。。

 
all = [[1,2,3,4],[1,2,5,6],[4,5,7,8],[1,8,3,4]]
set_all = [set(i) for i in all]
for i in range(len(all)):
    for j in range(len(all)):
        if i == j: 
            continue
        ncom = len(set_all[i].intersection(set_all[j]))
        print "List set %s has %s elements in common with set %s" % (i, ncom, j)

List set 0 has 2 elements in common with set 1
List set 0 has 1 elements in common with set 2
List set 0 has 3 elements in common with set 3
List set 1 has 2 elements in common with set 0
List set 1 has 1 elements in common with set 2
List set 1 has 1 elements in common with set 3
List set 2 has 1 elements in common with set 0
List set 2 has 1 elements in common with set 1
List set 2 has 2 elements in common with set 3
List set 3 has 3 elements in common with set 0
List set 3 has 1 elements in common with set 1
List set 3 has 2 elements in common with set 2

Answer 3

基本上你要做的是计算每个列表中元素集与每个其他列表的交点长度。试试这个：

a = [['a','b','c','d'],['r','d','g','s'],['e','r','a','b'],['p','o','i','u']]

for i in range(len(a)):
   for j in range(len(a)):
      print "item%d has %d same values as item%d" % ( i, len(set(a[i]) & set(a[j])) ,j )

输出格式并不完全符合您的要求，但您明白了。

Answer 4

如果你正在寻找最短的答案，因为你像我这样懒惰的人：）

>>> my_list = [['a','b','c','d'],['r','d','g','s'],['e','r','a','b'],['p','o','i','u']]
>>> for i, sub_list in enumerate(my_list):
...     print 'item %d shares with %r'%(i, map(lambda a, b: len(set(a) & set(b)), sub_list, my_list))
...
item 0 shares with [1, 0, 0, 0]
item 1 shares with [0, 1, 0, 0]
item 2 shares with [0, 1, 1, 0]
item 3 shares with [0, 0, 0, 1]

如何比较列表中的一个项目与此列表中的所有其他项目python

4 个答案: