从方阵中删除第一个对角元素的Python程序

给定一个 N*N 维的方阵，任务是编写一个Python程序去除第一条对角线。

例子：

Input : test_list = [[5, 3, 3, 2, 1], [5, 6, 7, 8, 2], [9, 3, 4, 6, 7], [0, 1, 2, 3, 5], [2, 5, 4, 3, 5]]

Output : [[3, 3, 2, 1], [5, 7, 8, 2], [9, 3, 6, 7], [0, 1, 2, 5], [2, 5, 4, 3]]

Explanation : Removed 5, 6, 4, 3, 5 from lists, 1st diagonals.

Input : test_list = [[5, 3, 3, 2], [5, 6, 7, 8], [9, 3, 4, 6], [0, 1, 2, 3]]

Output : [[3, 3, 2], [5, 7, 8], [9, 3, 6], [0, 1, 2]]

Explanation : Removed 5, 6, 4, 3 from lists, 1st diagonals.

方法 1：使用循环和enumerate()

在此我们使用循环遍历每一行，并将元素的索引与行号进行比较，如果发现相等，则省略该元素。

程序：

Python3

# initializing list
test_list = [[5, 3, 3, 2, 1], [5, 6, 7, 8, 2], [
    9, 3, 4, 6, 7], [0, 1, 2, 3, 5], [2, 5, 4, 3, 5]]
  
# printing original list
print("The original list is : " + str(test_list))
  
res = []
for idx, ele in enumerate(test_list):
  
    # removing element whose index is equal to row index
    res.append([el for idxx, el in enumerate(ele) if idxx != idx])
  
# printing result
print("Filtered Matrix : " + str(res))

输出：

The original list is : [[5, 3, 3, 2, 1], [5, 6, 7, 8, 2], [9, 3, 4, 6, 7], [0, 1, 2, 3, 5], [2, 5, 4, 3, 5]]

Filtered Matrix : [[3, 3, 2, 1], [5, 7, 8, 2], [9, 3, 6, 7], [0, 1, 2, 5], [2, 5, 4, 3]]

方法 2：使用列表推导和enumerate()

在此，我们使用列表理解来执行迭代任务，为上述方法提供一种线性解决方案。

程序：

蟒蛇3

# initializing list
test_list = [[5, 3, 3, 2, 1], [5, 6, 7, 8, 2], [
    9, 3, 4, 6, 7], [0, 1, 2, 3, 5], [2, 5, 4, 3, 5]]
  
# printing original list
print("The original list is : " + str(test_list))
  
# list comprehension to perform task as one liner
res = [[el for idxx, el in enumerate(ele) if idxx != idx]
       for idx, ele in enumerate(test_list)]
  
# printing result
print("Filtered Matrix : " + str(res))

输出：

The original list is : [[5, 3, 3, 2, 1], [5, 6, 7, 8, 2], [9, 3, 4, 6, 7], [0, 1, 2, 3, 5], [2, 5, 4, 3, 5]]

Filtered Matrix : [[3, 3, 2, 1], [5, 7, 8, 2], [9, 3, 6, 7], [0, 1, 2, 5], [2, 5, 4, 3]]