Python - 删除位置行

给定一个矩阵，任务是编写一个Python程序来删除具有特定位置的行。

例子：

Input: test_list = [[3, 5, 2], [1, 8, 9], 
                [5, 3, 1], [0, 1, 6], 
            [9, 4, 1], [1, 2, 10], 
            [0, 1, 2]]; idx_lis = [1, 2, 5]
Output: [[3, 5, 2], [0, 1, 6], [9, 4, 1], [0, 1, 2]]
Explanation: 1st, 2nd and 5th rows are removed.

Input: test_list = [[3, 5, 2], [1, 8, 9], 
             [5, 3, 1], [0, 1, 6], 
             [9, 4, 1], [1, 2, 10], 
             [0, 1, 2]]; idx_lis = [1, 3, 5]
Output: [[3, 5, 2], [5, 3, 1], [9, 4, 1], [0, 1, 2]]
Explanation: 1st, 3rd and 5th rows are removed.

方法 #1：使用循环+ pop() +反向迭代

在这种情况下，使用 pop() 处理删除，并且需要反向迭代以确保由于删除时的重新排列，错误的位置行不会被删除。

Python3

# Python3 code to demonstrate working of
# Remove positional rows
# Using loop + pop() + back iteration
  
# initializing list
test_list = [[3, 5, 2], [1, 8, 9], [5, 3, 1], 
             [0, 1, 6], [9, 4, 1], [1, 2, 10], 
             [0, 1, 2]]
  
# printing original list
print("The original list is: " + str(test_list))
  
# initializing indices
idx_lis = [1, 2, 5]
  
# back iteration
for idx in idx_lis[::-1]:
  
    # pop() used for removal
    test_list.pop(idx)
  
# printing result
print("Matrix after removal: " + str(test_list))

输出：

The original list is: [[3, 5, 2], [1, 8, 9], [5, 3, 1], [0, 1, 6], [9, 4, 1], [1, 2, 10], [0, 1, 2]]

Matrix after removal: [[3, 5, 2], [0, 1, 6], [9, 4, 1], [0, 1, 2]]

方法 #2：使用enumerate() +列表理解

在这种情况下，我们不是按索引删除行，而是执行仅添加不属于删除索引列表的行的任务。

蟒蛇3

# Python3 code to demonstrate working of
# Remove positional rows
# Using enumerate() + list comprehension
  
# initializing list
test_list = [[3, 5, 2], [1, 8, 9], [5, 3, 1], 
             [0, 1, 6], [9, 4, 1], [1, 2, 10], 
             [0, 1, 2]]
  
# printing original list
print("The original list is: " + str(test_list))
  
# initializing indices
idx_lis = [1, 2, 5]
  
# using enumerate() to get index and value of each row
res = [sub[1] for sub in enumerate(test_list) if sub[0] not in idx_lis]
  
# printing result
print("Matrix after removal: " + str(res))

输出：

The original list is: [[3, 5, 2], [1, 8, 9], [5, 3, 1], [0, 1, 6], [9, 4, 1], [1, 2, 10], [0, 1, 2]]

Matrix after removal: [[3, 5, 2], [0, 1, 6], [9, 4, 1], [0, 1, 2]]