As with lists, the in operator can be applied to tuples and sets to check whether an item is a member of the collection:
| >>> odds = set([1, 3, 5, 7, 9]) |
| >>> 9 in odds |
| True |
| >>> 8 in odds |
| False |
| >>> '9' in odds |
| False |
| >>> evens = (0, 2, 4, 6, 8) |
| >>> 4 in evens |
| True |
| >>> 11 in evens |
| False |
When used on a dictionary, in checks whether a value is a key in the dictionary:
| >>> bird_to_observations = {'canada goose': 183, 'long-tailed jaeger': 71, |
| ... 'snow goose': 63, 'northern fulmar': 1} |
| >>> 'snow goose' in bird_to_observations |
| True |
| >>> 183 in bird_to_observations |
| False |
Notice that the values in the dictionary are ignored; the in operator only looks at the keys.