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The Python set add() method adds a given element to a set if the element is not present in the set in Python

Parameters:

• elem: The element that needs to be added to a set.

Returns: None

## Python Set add() Method Examples

Before going to the example we are assuming the time complexity of the set.add() function is O(1) because the set is implemented using a hash table.

### Add a new element to a Python set

It is used to add a new element to the set if it is not existing in a set.

## Python3

 `# set of letters` `GEEK ``=` `{``'g'``, ``'e'``, ``'k'``}`   `# adding 's'` `GEEK.add(``'s'``)` `print``(``"Letters are:"``, GEEK)`   `# adding 's' again` `GEEK.add(``'s'``)` `print``(``"Letters are:"``, GEEK)`

Output:

```Letters are: {'e', 's', 'g', 'k'}
Letters are: {'e', 's', 'g', 'k'}```

It is used to add an existing element to the set if it is existing in the Python set and check if it gets added or not.

## Python3

 `# set of letters` `GEEK ``=` `{``6``, ``0``, ``4``}`   `# adding 1` `GEEK.add(``1``)` `print``(``'Letters are:'``, GEEK)`   `# adding 0` `GEEK.add(``0``)` `print``(``'Letters are:'``, GEEK)`

Output:

```Letters are: {0, 1, 4, 6}
Letters are: {0, 1, 4, 6}```

### Adding any iterable to a set

We can add any Python iterable to a set using Python add or Python update function, if we try to add a list using the add function we get an unhashable Type error.

## Python3

 `# Python code to demonstrate addition of tuple to a set.` `s ``=` `{``'g'``, ``'e'``, ``'e'``, ``'k'``, ``'s'``}` `t ``=` `(``'f'``, ``'o'``)` `l ``=` `[``'a'``, ``'e'``]`   `# adding tuple t to set s.` `s.add(t)`   `# adding list l to set s.` `s.update(l)`   `print``(s)`

Output :

`{'a', 'g', 'k', 'e', ('f', 'o'), 's'}`

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