Membership Operators

Membership operators are used to check if a value exists inside a sequence (like a sentence of text or a list of items).

Think of it as searching for something inside a container.

Python has two membership keywords: in and not in.

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1. The in Operator

Returns True if the value is found inside the container.

Searching inside text (Strings):

sentence = "Python is the future of AI"

# Check if the word "AI" is inside the sentence
print("AI" in sentence)      # Output: True
print("Java" in sentence)    # Output: False

Searching inside lists:

# A list of names (we will learn more about lists later!)
names = ["Rahul", "Sai", "Priya"]

print("Sai" in names)    # Output: True
print("John" in names)   # Output: False

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2. The not in Operator

Returns True if the value is not found inside the container (returns the opposite of in).

sentence = "Python is the future of AI"

print("Java" not in sentence)  # Output: True (Java is indeed not there!)
print("AI" not in sentence)    # Output: False (Because AI is there!)

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Quick Summary

• in Operator: Checks if an element exists inside a collection (string, list, tuple, etc.) and returns True if found.
• not in Operator: Checks if an element is absent from a collection and returns True if missing.
• Membership in Strings: Searches sub-strings within larger text (e.g., "AI" in "Python for AI" -> True).

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What's Next?

Congratulations on completing Module 4! Now that we know all the operators, let's learn how to make smart decisions in code using Conditional Statements (if, elif, else) in Module 5!