Python中按索引比较列表值

Question

我需要查看一个列表中的两个项目是否出现在另一个列表中，如果出现，请按它们在另一个列表中的位置比较它们。伪代码示例：

j=0
for x in mylist #loop through the list
    i=0
    for y in mylist #loop through the list again to compare items
        if index of mylist[j] > index of mylist[i] in list1 and list2:
            score[i][j] = 1 #writes the score to a 2d array(numpy) called score
            i=i+1
        else: 
            score[i][j]=0
            i=i+1
j=j+1

叙述性描述示例：

Names = [John, James, Barry, Greg, Jenny]
Results1 = [James, Barry, Jenny, Greg, John]
Results2 = [Barry, Jenny, Greg, James, John]

loop through Names for i
    loop through Names for j
        if (index value for john) > (index value for james) in results1 and 
           (index value for john) > (index value for james) results2:
            score[i][j] = 1

有人能告诉我正确的方向吗？我看了很多列表、数组和索引教程，但似乎没有什么能回答我的问题

Answer 1

将list2转换为对给定项的位置进行编码的字典：

dic2 = dict((item,i) for i,item in enumerate(list2))

现在可以使用x in dic2 and y in dic2测试列表中的内容，并使用dic2[x]获取列表中的索引。

编辑：这违背了我的直觉，但这里是完整的代码。第一部分是使用我上面展示的内容，将一个简单的列表转换为索引的查找。接下来是初始化2D列表的标准if-unintive方法。接下来是循环，使用非常方便的enumerate函数为列表中的每个名称分配一个索引。

Names = ['John', 'James', 'Barry', 'Greg', 'Jenny']
Results1 = ['James', 'Barry', 'Jenny', 'Greg', 'John']
Results2 = ['Barry', 'Jenny', 'Greg', 'James', 'John']

Order1 = dict((name,order) for order,name in enumerate(Results1))
Order2 = dict((name,order) for order,name in enumerate(Results2))

score = [[0]*len(Names) for y in range(len(Names))]

for i,name1 in enumerate(Names):
    for j,name2 in enumerate(Names):
        if name1 in Order1 and name2 in Order1 and Order1[name1] > Order1[name2] and name1 in Order2 and name2 in Order2 and Order2[name1] > Order2[name2]:
            score[i][j] = 1

Answer 2

如果我理解您的意图，这里有一个方法：

score={}

Names = ["John", "James", "Barry", "Greg", "Jenny"]
Results1 = ["James", "Barry", "Jenny", "Greg", "John"]
Results2 = ["Barry", "Jenny", "Greg", "James", "John"]

r1dict={name:i for i,name in enumerate(Results1)}
r2dict={name:i for i,name in enumerate(Results2)}

for i, ni in enumerate(Names):
    for j, nj in enumerate(Names):
        if r1dict[ni] > r2dict[nj]:
            score[(i,j)]=1

print(score)  

印刷品：

{(0, 1): 1, (3, 2): 1, (4, 4): 1, (3, 3): 1, (2, 2): 1, 
 (4, 2): 1, (0, 3): 1, (0, 4): 1, (3, 4): 1, (0, 2): 1}

Answer 3

lis1=[1,2,3,4,5,6,7,8]
num1=lis1[1]
num2=lis1[4]
lis2=[11,12,13,14,2,7,5,34]
if num1 in lis2 and num2 in lis2:
    if lis2.index(num1)>lis2.index(num2):
        #do something here
    else:
        #do something else