in
KeywordPython 2.0+Beginner
Membership test operator; also used in for loops to iterate over items
Quick Info
- Documentation
- Official Docs
- Python Version
- 2.0+
Learn by Difficulty
Quick Example
python
# in with lists fruits = ["apple", "banana", "cherry"] print("banana" in fruits) print("grape" in fruits) # in with strings text = "Hello, World!" print("World" in text) print("xyz" in text) # in with dictionaries (checks keys) ages = {"Alice": 30, "Bob": 25} print("Alice" in ages) print(30 in ages) # checks keys, not values
'in' tests membership. For lists it checks values, for strings it checks substrings, for dicts it checks keys.
Try in PlaygroundTags
languagesyntaxcoremembershipiterationoperator