Learn Python by Building Data Science Applications

Sets

Sets are—in a way—dictionaries without values. First, they use the same curly brackets, and second, their members cannot be duplicated, which are both similar to dictionary keys. Because of that, they are handy to use for deduplication or membership tests. On top of that, sets have built-in mathematical operations, unions, intersections, differences, and symmetrical differences:

>>> names = set(['Sam', 'John', 'James', 'Sam'])>>> names{'James', 'John', 'Sam'}>>> other_names = {'James', 'Nikolai', 'Iliah'}>>> names.difference(other_names){'John', 'Sam'}>>> names.symmetric_difference(other_names){'Iliah', 'John', 'Nikolai', 'Sam'}

Sets don't have an order and, compared to dictionaries, do not guarantee that the order of representation ...