How can I check if a string contains a substring in Python?
Gable E

In Python, there are multiple ways to check if a string contains a substring. Here's a detailed explanation of some commonly used approaches: 1. Using thein operator: You can use thein operator to check if a substring is present in a string. It returnsTrue if the substring is found, andFalse otherwise.

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string = "Hello, World!"

if "Hello" in string:
    print("Substring found.")
else:
    print("Substring not found.")

2. Using thefind() method: Thefind() method returns the index of the first occurrence of a substring within a string. If the substring is not found, it returns -1.

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string = "Hello, World!"

index = string.find("Hello")

if index != -1:
    print("Substring found at index", index)
else:
    print("Substring not found.")

3. Using theindex() method (with error handling): Similar tofind(), theindex() method returns the index of the first occurrence of a substring. However, if the substring is not found, it raises aValueError. You can handle this exception to determine if the substring exists in the string.

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string = "Hello, World!"

try:
    index = string.index("Hello")
    print("Substring found at index", index)
except ValueError:
    print("Substring not found.")

4. Using regular expressions (with there module): If you need more advanced pattern matching, you can use regular expressions. There module provides methods likesearch() ormatch() to search for patterns within a string.

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import re

string = "Hello, World!"

if re.search("Hello", string):
    print("Substring found.")
else:
    print("Substring not found.")

These are some of the commonly used methods to check if a string contains a substring in Python. Choose the approach that suits your requirements and the complexity of the pattern you need to match.

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