How to Check if a String Contains a Specific Word with Python

In programming, it is often necessary to check if a string contains a specific word or substring. This can be useful for tasks such as searching for keywords in text, parsing data, or filtering input. In this tutorial, we will explore different ways to check if a string contains a specific word in Python.

Step 1: Using the ‘in’ Keyword

The simplest way to check if a string contains a specific word is to use the ‘in’ keyword. This keyword is used to check if a value exists in a sequence, such as a string or a list.

Here’s an example:

 string = "The quick brown fox jumps over the lazy dog"
 if "fox" in string:
     print("The string contains 'fox'")
 else:
     print("The string does not contain 'fox'")

In this example, we define a string and check if the word “fox” is in the string using the ‘in’ keyword. If the word is in the string, we print a message saying that the string contains the word. Otherwise, we print a message saying that the string does not contain the word.

Step 2: Using the find() Method

Another way to check if a string contains a specific word is to use the find() method. This method returns the index of the first occurrence of a substring in a string, or -1 if the substring is not found.

Here’s an example:

 string = "The quick brown fox jumps over the lazy dog"
 if string.find("fox") != -1:
     print("The string contains 'fox'")
 else:
     print("The string does not contain 'fox'")

In this example, we use the find() method to search for the word “fox” in the string. If the method returns a value other than -1, we know that the word is in the string and print a message saying so. Otherwise, we print a message saying that the word is not in the string.

Step 3: Using Regular Expressions

Regular expressions are a powerful tool for working with text. They allow you to search for patterns in strings and perform complex operations on them.

To use regular expressions in Python, we need to import the re module. Here’s an example:

import re

string = "The quick brown fox jumps over the lazy dog"
if re.search(r"\bfox\b", string):
print("The string contains 'fox'")
else:
print("The string does not contain 'fox'")

In this example, we use the search() method from the re module to search for the word “fox” in the string. The ‘\b’ characters are used to match the word boundary, ensuring that we only match the whole word and not a substring. If the search is successful, we print a message saying that the word is in the string. Otherwise, we print a message saying that the word is not in the string.

In this tutorial, we have explored different ways to check if a string contains a specific word in Python. Whether you prefer the simplicity of the ‘in’ keyword, the flexibility of the find() method, or the power of regular expressions, there is a solution for every situation. By mastering these techniques, you will be better equipped to work with text data in your Python programs.