7.3.2. Manipulating Elements
Sets are mostly used for mathematical operations instead of storing data for later use as is the case for tuples and list. Due to this, set only provides a small set of operations to manipulate its elements.
Adding Elements (set.add() method)
set.add() can be used to add elements to a set.
s1 = {'a', 'b', 'c'}
s1.add('d')
print(s1)
{'a', 'b', 'c', 'd'}
Note
Keep in mind that order of elements isn't fixed and duplicates are not allowed in sets.
There are other operations that can be used to add elements such as union operation which are covered in later section.
Removing Elements with set.pop()
set.pop() can be used to remove a random element from the set. It
returns the removed element.
s1 = {'a', 'b', 'c'}
print(s1.pop())
print(s1)
b
{'a', 'c'}
Unlike list.pop(), this method does not remove element
in a fixed order and doesn't take any index since sets are not
indexable.
Everytime the program is run, a different or random element is popped.
If set is empty, a KeyError is raised.
Removing Elements with set.remove()
set.remove() removes the given item from set.
s1 = {'a', 'b', 'c'}
s1.remove('a')
print(s1)
{'b', 'c'}
set.remove() raises a KeyError if item is not found in
the set.
Removing all elements
A set can be emptied using the set.clear() methods which
deletes all the elements from the set.
s1 = {'a', 'b', 'c'}
s1.clear()
print(s1)
set()
Note
set() implies empty set.