Question

我有一个元组列表：

tuples_list = [(1,0), (2,3), (3,2), (2,0)]

我想使用其中一些元组访问二维数组a的元素，例如

for i in range(3):
    print a[tuples_list[i]]

应该输出a[1][0], a[2][3], a[3][2]的值。只是为了澄清，a就像是

a = [[1,2,3,4],[5,6,7,8],[9,10,11,12],[13,14,15,16],[17,18,19,20],[21,22,23,24]]

Answer 1

实现这一目标的典型方法是在for循环中使用元组解包，如下所示：

a = [[1,2,3,4],[5,6,7,8],[9,10,11,12],[13,14,15,16],[17,18,19,20],[21,22,23,24]]
tuples_list = [(1,0), (2,3), (3,2), (2,0)]
for x,y in tuples_list:
    print a[x][y]

Answer 2

使用元组解包将元组拆分为两个变量：

>>> tuples_list = [(1,0), (2,3), (3,2), (2,0)]
>>> a = [[1,2,3,4], [5,6,7,8], [9,10,11,12], [13,14,15,16], [17,18,19,20], [21,22,23,24]]
>>> for indexes in tuples_list:
...     i, j = indexes  # tuple unpacking
...     print a[i][j]
...
5
12
15
9

>>> for i, j in tuples_list:  # tuple unpacking
...     print a[i][j]
...
5
12
15
9

Answer 3

这应该做的工作：

for i in range(len(tuples_list)):
    list_index, element_index = tuples_list[i]
    print(a[list_index][element_index])

Python - 使用元组作为列表索引

3 个答案: