Adding and Deleting elements - set

Let us see how we can add and delete elements to the set in Python.

  • We can add elements to set or update existing ones.

    • add

    • update

    • union

  • We can delete elements from the set using different functions.

    • pop

    • remove

    • discard

    • clear

s = {1, 2, 3, 3, 3, 4, 4}

s.add(5)

s

{1, 2, 3, 4, 5}

s.update?

Docstring: Update a set with the union of itself and others.
Type:      builtin_function_or_method

s.update({4, 5, 6, 7}) # Updates the set on which update is invoked

s

{1, 2, 3, 4, 5, 6, 7}

s.union?

Docstring:
Return the union of sets as a new set.

(i.e. all elements that are in either set.)
Type:      builtin_function_or_method

s = {1, 2, 3, 4, 5}
s.union({4, 5, 6, 7}) # Creates new set

{1, 2, 3, 4, 5, 6, 7}

s

{1, 2, 3, 4, 5}

s.pop?

Docstring:
Remove and return an arbitrary set element.
Raises KeyError if the set is empty.
Type:      builtin_function_or_method

s.pop()

1

s

{2, 3, 4, 5}

s.remove?

Docstring:
Remove an element from a set; it must be a member.

If the element is not a member, raise a KeyError.
Type:      builtin_function_or_method

s.remove(4)

s

{2, 3, 5}

s.remove(6) # 6 does not exist, throws KeyError

---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
<ipython-input-17-b3638b2cbd97> in <module>
----> 1 s.remove(6) # 6 does not exist, throws KeyError

KeyError: 6

s = {1, 2, 3, 4, 5}

s.discard?

Docstring:
Remove an element from a set if it is a member.

If the element is not a member, do nothing.
Type:      builtin_function_or_method

s.discard(4)

s

{1, 2, 3, 5}

s.discard(6)

s

{1, 2, 3, 5}

s.clear?

Docstring: Remove all elements from this set.
Type:      builtin_function_or_method

s.clear()

s

set()
Other list operations Typical set operations