Article Summary
Checking if a Python string contains a substring is a common coding task with several built-in solutions. This article covers `in`, `__contains__()`, `find()`, `index()`, `count()`, and regex. Readers will know exactly which method fits their use case.
Checking if a string contains a substring is a task that comes up often when you are using any programming language, and if you’re trying to figure out how to do that in Python, you’re in luck. You have many options to check if a Python string contains a substring.
Below are some ways you can check for a substring in Python. Of these, using the operator is the most common when you only need to check the existence of the substring. Still, you may need other information besides a simple Boolean, so the other methods here can be just as valuable.
Using the Python string contains method
The python str class has a __contains__() method that will check if a python string contains a substring. It will return true if it’s found and will return false if it’s not. You will notice that the method name is wrapped in two underscores. This prevents this method from being overridden by a subclass or accessed accidentally.
You can use it in two ways. The first is to use the contains method of the String object you are checking:
| my_string = ‘This is the string being checked.” my_substring = ‘string’ if (my_string.__contains__(my_substring)): print(“String contains substring!”) else: print(“String does not contain substring”) |
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Frequently Asked Questions
Do you know all the ways to locate substrings in Python? Discover new — and easy — methods of checking if your Python string contains a substring. This guide provides structured insights, proven methodologies, and actionable execution steps for modern professionals.
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