Python program to Extract string till first Non-Alphanumeric character

Last Updated : 01 Oct, 2020

Given a string, extract all the alphanumerics before 1st occurrence of non-alphanumeric.

Input : test_str = ‘geek$s4g!!!eeks’
Output : geek
Explanation : Stopped at $ occurrence.
Input : test_str = ‘ge)eks4g!!!eeks’
Output : ge
Explanation : Stopped at ) occurrence.

Method #1 : Using regex + search()

In this, search() is used to search appropriate regex() for alphanumerics, then the result is sliced till 1st occurrence of a non-alphanumeric character

Python3

# Python3 code to demonstrate working of 
# Extract string till first Non-Alphanumeric character
# Using regex + search()
import re
  
# initializing string
test_str = 'geeks4g!!!eeks'
  
# printing original string
print("The original string is : " + str(test_str))
  
# using start() to get 1st substring
res = re.search(r'\W+', test_str).start()
res = test_str[0 : res]
          
# printing result 
print("The resultant string : " + str(res))

Output

The original string is : geeks4g!!!eeks
The resultant string : geeks4g

Method #2 : Using findall()

This is yet another regex way to solve this problem. In this, we extract the 1st substring before non-alnum character by accessing the 0th index.

Python3

# Python3 code to demonstrate working of 
# Extract string till first Non-Alphanumeric character
# Using findall()
import re
  
# initializing string
test_str = 'geeks4g!!!eeks'
  
# printing original string
print("The original string is : " + str(test_str))
  
# using findall() to get all substrings 
# 0th index gives 1st substring
res = re.findall("[\dA-Za-z]*", test_str)[0]
          
# printing result 
print("The resultant string : " + str(res))

Output

The original string is : geeks4g!!!eeks
The resultant string : geeks4g

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