Python程序反转列表中的范围

给定一个列表，我们的任务是编写一个Python程序来反转列表中的一个范围。

例子：

Input : test_list = [6, 3, 1, 8, 9, 2, 10, 12, 7, 4, 11], str, end = 3, 9

Output : [6, 3, 1, 7, 12, 10, 2, 9, 8, 4, 11]

Explanation : 8, 9, 2, 10, 12, 7 are reversed in list to 7, 12, 10, 2, 9, 8.

Input : test_list = [6, 3, 1, 8, 9, 2, 10, 12, 7, 4, 11], str, end = 8, 9

Output : [6, 3, 1, 8, 9, 2, 10, 7, 12, 4, 11]

Explanation : 12, 7 are reversed in list to 7, 12.

方法 #1：使用reverse() +循环

在此示例中，使用 reverse() 提取和反转子列表。接下来使用循环将范围元素替换为反向元素。

Python3

# Python3 code to demonstrate working of
# Reversing a range
# Using reverse() + loop
  
# initializing list
test_list = [6, 3, 1, 8, 9, 2, 10, 12, 7, 4, 11]
               
# printing original list
print("The original list is : " + str(test_list))
  
# initializing range 
strt, end = 3, 9
  
# reversing list and assigning the range
temp = test_list[strt:end]
temp.reverse()
for idx in range(strt, end):
    test_list[idx] = temp[idx - strt]
          
# printing result
print("Range reversed range list : " + str(test_list))

输出：

The original list is : [6, 3, 1, 8, 9, 2, 10, 12, 7, 4, 11]
Range reversed range list : [6, 3, 1, 7, 12, 10, 2, 9, 8, 4, 11]

方法 #2：使用列表split() +切片

解决此问题的紧凑方法是使用列表拆分方式执行范围列表的反转，该方式仅反转切片所需的范围。

蟒蛇3

# Python3 code to demonstrate working of
# Reversing a range
# Using list split + slicing
  
# initializing list
test_list = [6, 3, 1, 8, 9, 2, 10, 12, 7, 4, 11]
               
# printing original list
print("The original list is : " + str(test_list))
  
# initializing range 
strt, end = 3, 9
  
# Third arg. of split with -1 performs reverse 
test_list[strt:end] = test_list[strt:end][::-1]
  
# printing result
print("Range reversed range list : " + str(test_list))

输出：

The original list is : [6, 3, 1, 8, 9, 2, 10, 12, 7, 4, 11]
Range reversed range list : [6, 3, 1, 7, 12, 10, 2, 9, 8, 4, 11]