Python – 删除 K 后的 N 个字符

给定一个字符串，删除 K 个字符后的 N 个字符。

Input : test_str = ‘ge@987eksfor@123geeks is best@212 for cs’, N = 3, K = ‘@’
Output : ‘geeksforgeeks is best for cs’
Explanation : All 3 required occurrences removed.

Input : test_str = ‘geeksfor@123geeks is best for cs’, N = 3, K = ‘@’
Output : ‘geeksforgeeks is best for cs’
Explanation : @123 is removed.

方法#1：使用 re.sub()

在此，我们指定适当的正则表达式来捕获元素并从字符串中删除接下来的 N 次出现。 sub() 用于执行替换。

Python3

# Python3 code to demonstrate working of 
# Remove N characters after K
# Using re.sub()
import re
  
# initializing strings
test_str = 'geeksfor@123geeks is best@212 for cs'
  
# printing original string
print("The original string is : " + str(test_str))
  
# initializing N 
N = 3
  
# initializing K 
K = '@'
  
# using re.sub() to perform task 
res = re.sub(r'\@...', '', test_str)
  
# printing result 
print("The String after removal : " + str(res))

输出

The original string is : geeksfor@123geeks is best@212 for cs
The String after removal : geeksforgeeks is best for cs

方法#2：使用 re.sub() + 出现选项

这与上面类似，只是使用 re.sub() 的第四个参数来控制我们希望执行替换的出现次数。

Python3

# Python3 code to demonstrate working of 
# Remove N characters after K
# Using re.sub() + occurrence option
import re
  
# initializing strings
test_str = 'geeksfor@123geeks is best@212 for cs'
  
# printing original string
print("The original string is : " + str(test_str))
  
# initializing N 
N = 3
  
# initializing K 
K = '@'
  
# using re.sub() to perform task 
# controlling occurrence using 4th arg.
# removes just 1st occurrence
res = re.sub(r'\@...', '', test_str, 1)
  
# printing result 
print("The String after removal : " + str(res)) 

输出

The original string is : geeksfor@123geeks is best@212 for cs
The String after removal : geeksforgeeks is best@212 for cs