6.3.2 Mathematical Set Operations

Union

  • The union of two sets is a set consisting of all the unique elements from both sets.
  • The union operator requires two sets, but method union may receive any iterable as its argument (this is true for subsequent methods in this section as well).
In [1]:
{1, 3, 5} | {2, 3, 4}
Out[1]:
{1, 2, 3, 4, 5}
In [2]:
{1, 3, 5}.union([20, 20, 3, 40, 40])
Out[2]:
{1, 3, 5, 20, 40}

Intersection

The intersection of two sets is a set consisting of all the unique elements that the two sets have in common.

In [3]:
{1, 3, 5} & {2, 3, 4}
Out[3]:
{3}
In [4]:
{1, 3, 5}.intersection([1, 2, 2, 3, 3, 4, 4])
Out[4]:
{1, 3}

Difference

The difference between two sets is a set consisting of the elements in the left operand that are not in the right operand.

In [5]:
{1, 3, 5} - {2, 3, 4}
Out[5]:
{1, 5}
In [6]:
{1, 3, 5, 7}.difference([2, 2, 3, 3, 4, 4])
Out[6]:
{1, 5, 7}

Symmetric Difference

The symmetric difference between two sets is a set consisting of the elements of both sets that are not in common with one another.

In [7]:
{1, 3, 5} ^ {2, 3, 4}
Out[7]:
{1, 2, 4, 5}
In [8]:
{1, 3, 5, 7}.symmetric_difference([2, 2, 3, 3, 4, 4])
Out[8]:
{1, 2, 4, 5, 7}

Disjoint

Two sets are disjoint if they do not have any common elements.

In [9]:
{1, 3, 5}.isdisjoint({2, 4, 6})
Out[9]:
True
In [10]:
{1, 3, 5}.isdisjoint({4, 6, 1})
Out[10]:
False

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