HackerRank Python Solution - Sets - .difference() operation

.difference():

• The tool .difference() returns a set with all the elements from the set that are not in an iterable. Sometimes the - operator is used in place of the .difference() tool, but it only operates on the set of elements in the set.

• Set is immutable to the .difference() operation (or the - operation).

HackerRank Python Solution - Sets - .intersection() operation

.intersection():

• The .intersection() operator returns the intersection of a set and the set of elements in an iterable. Sometimes, the & operator is used in place of the .intersection() operator, but it only operates on the set of elements in the set.

• The set is immutable to the .intersection() operation (or & operation).

HackerRank Python Solution - Sets - .union() Operation

.union():

• The .union() operator returns the union of a set and the set of elements in an iterable. Sometimes, the | operator is used in place of .union() operator, but it operates only on the set of elements in set.

• Set is immutable to the .union() operation (or | operation).

HackerRank Python Solution - Sets - .discard(), .remove() & .pop()

.remove(x):

• This operation removes element x from the set.

• If element x does not exist, it raises a KeyError.

• The .remove(x) operation returns None.

Example:

>>> s = set([1, 2, 3, 4, 5, 6, 7, 8, 9])
>>> s.remove(5)
>>> print s
set([1, 2, 3, 4, 6, 7, 8, 9])
>>> print s.remove(4)
None
>>> print s
set([1, 2, 3, 6, 7, 8, 9])
>>> s.remove(0)
KeyError: 0

HackerRank Python Solution - Sets - .add()

• If we want to add a single element to an existing set, we can use the .add() operation.

• It adds the element to the set and returns 'None'.

Example:

>>> s = set('HackerRank')
>>> s.add('H')
>>> print s
set(['a', 'c', 'e', 'H', 'k', 'n', 'r', 'R'])
>>> print s.add('HackerRank')
None
>>> print s
set(['a', 'c', 'e', 'HackerRank', 'H', 'k', 'n', 'r', 'R'])