Python – Check if String Contain Only Defined Characters using Regex
In this article, we are going to see how to check whether the given string contains only certain set of characters in Python. These defined characters will be represented using sets.
Input: ‘657’ let us say regular expression contain following characters-
Output: Valid Explanation: The Input string only consist of characters present in the given string Input: ‘7606’ let us say regular expression contain following characters-
Check if String Contain Only Defined Characters using Regex:
Method or approach is simple we will define the character set using a regular expression. The regular expression is a special pattern or sequence of characters that will allow us to match and find other sets of characters or strings.
- compile(): Regular expressions are compiled into pattern objects, which have methods for various operations such as searching for pattern matches or performing string substitutions.
- search(): re.search() method either returns None (if the pattern doesn’t match), or a re.MatchObject that contains information about the matching part of the string. This method stops after the first match, so this is best suited for testing a regular expression more than extracting data.
Below is the implementation.
Time complexity : O(n)
Space Complexity : O(1)
Whether you're preparing for your first job interview or aiming to upskill in this ever-evolving tech landscape, GeeksforGeeks Courses
are your key to success. We provide top-quality content at affordable prices, all geared towards accelerating your growth in a time-bound manner. Join the millions we've already empowered, and we're here to do the same for you. Don't miss out - check it out now!