Set

instance of set class. unordered sequence of elements. contain unique elements. it is mutable object. usually contain same data type. elements have no index.

creating a set

use {} to create a set. you cannot add mutable objects (list, dict) to the set. only immutable objects (str, int, float, tuple, frozenset) can be added to the set. not allowed to create empty set using {}, you have to use set().

get length

use len()

access element

As set element do not have index, you can not access element by index. but you can use in keyword to check if element is present in the set.

set theory

todo

set methods

there are many methods.

• add() - add element to the set
• union() - return the union of two sets
• update() - update the set with the union of itself and others
• remove() - remove element from the set, produce error if element not present
• discard() - remove element from the set if it is present
• difference() - return the difference of two sets
• intersection() - return the intersection of two sets
• issubset() - test whether every element in the set is in another set
• issuperset() - test whether every element in another set is in the set
• pop() - remove and return an arbitrary set element
• clear() - remove all elements from the set
• copy() - return a copy of the set