Skip to content
Related Articles

Related Articles

Python Program to Count characters surrounding vowels
  • Last Updated : 11 Dec, 2020

Given a String, the task is to write a Python program to count those characters which have vowels as their neighbors.

Examples:

Input : test_str = ‘geeksforgeeksforgeeks’ 
Output : 10 
Explanation : g, k, f, r, g, k, f, r, g, k have surrounding vowels.

Input : test_str = ‘geeks’ 
Output : 2 
Explanation : g, k have surrounding vowels. 
 

Method 1 : Using loop



In this, we increment counter while checking previous and successive element for vowels using loop.

Python3




# initializing string
test_str = 'geeksforgeeksforgeeks'
  
# printing original string
print("The original string is : " + str(test_str))
  
res = 0
vow_list = ['a', 'e', 'i', 'o', 'u']
for idx in range(1, len(test_str) - 1):
  
    # checking for preceding and succeeding element to be vowel
    if test_str[idx] not in vow_list and (test_str[idx - 1] in vow_list or test_str[idx + 1] in vow_list):
        res += 1
  
# solving for 1st and last element
if test_str[0] not in vow_list and test_str[1] in vow_list:
    res += 1
  
if test_str[-1] not in vow_list and test_str[-2] in vow_list:
    res += 1
  
# printing result
print("Characters around vowels count : " + str(res))

Output:

The original string is : geeksforgeeksforgeeks

Characters around vowels count : 10

Method 2 : Using sum() and list comprehension

In this, we perform the task of getting count using sum() and iteration and filtering is done using list comprehension.

Python3




# initializing string
test_str = 'geeksforgeeksforgeeks'
  
# printing original string
print("The original string is : " + str(test_str))
  
vow_list = ['a', 'e', 'i', 'o', 'u']
  
# sum() accumulates all vowels surround elements
res = sum([1 for idx in range(1, len(test_str) - 1) if test_str[idx]
           not in vow_list and (test_str[idx - 1] in vow_list or test_str[idx + 1] in vow_list)])
  
# solving for 1st and last element
if test_str[0] not in vow_list and test_str[1] in vow_list:
    res += 1
  
if test_str[-1] not in vow_list and test_str[-2] in vow_list:
    res += 1
  
# printing result
print("Characters around vowels count : " + str(res))

 Output:

The original string is : geeksforgeeksforgeeks

Characters around vowels count : 10

 

Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course.

My Personal Notes arrow_drop_up
Recommended Articles
Page :