Python program to Increment Suffix Number in String

Given a String, the task is to write a Python program to increment the number which is at end of the string.

Input : test_str = ‘geeks006’ 
Output : geeks7 
Explanation : Suffix 006 incremented to 7.

Input : test_str = ‘geeks007’ 
Output : geeks8 
Explanation : Suffix 007 incremented to 8. 

Method #1 : Using findall() + join() + replace()

In this, strategy we perform the task of finding number using findall(), then perform the task of separating numeric string and prefix string, then an increment of a numeric string is performed. At last, the string is joined to get a prefix followed by an incremented number.

Python3

# Python3 code to demonstrate working of
# Increment Suffix Number
# Using findall() + join() + replace()
import re

# initializing string
test_str = 'geeks006'

# printing original string
print("The original string is : " + str(test_str))

# getting suffix number
reg = re.compile(r'[ 0 - 9]')
mtch = reg.findall(test_str)

# getting number
num = ''.join(mtch[-3 : ])
pre_str = test_str.replace(num, '')

# Increment number
add_val = int(num) + 1

# joining prefix str and added value
res = pre_str + str(add_val)

# printing result
print("Incremented numeric String : " + str(res))

Output:

The original string is : geeks006
Incremented numeric String : geeks61

Method #2 : Using sub() + group() + zfill()

In this, we perform the task of grouping numbers using group() and incrementing, zfill() is used for task of filling the required leading values in numerical. The sub() is used to find the numerical part of strings.

Python3

# Python3 code to demonstrate working of
# Increment Suffix Number
# Using sub() + group() + zfill()
import re

# initializing string
test_str = 'geeks006'

# printing original string
print("The original string is : " + str(test_str))

# fstring used to form string
# zfill fills values post increment
res = re.sub(r'[0-9]+$',
             lambda x: f"{str(int(x.group())+1).zfill(len(x.group()))}",
             test_str)

# printing result
print("Incremented numeric String : " + str(res))

Output:

The original string is : geeks006
Incremented numeric String : geeks007

The Time and Space Complexity for all the methods are the same:

Time Complexity: O(n)

Space Complexity: O(n)