\subsection{Empty Set Literal}

People, who are new to Python, meeting the built-in set type for the first time often get confused when trying to create an empty set by using the \lstinline|{}| literal.

This literal is already reserved for creating empty dictionaries.

The normal way to create a new empty set in Python is to use the \lstinline{set()} constructor.

However, if you like, you can use a literal, too!

\lstinputlisting[caption=empty\_set\_literal.py]{../standard_lib/empty_set_literal.py}

What happens here is that an empty list (using the list literal \lstinline{[]}) is created and unpacked using the \lstinline{*}-operator.

The elements from the unpacked empty list are passed to the curly braces.

Even though no elements at all are passed to the set literal, Python accepts it as valid set creation syntax.

\begin{lstlisting}[caption=Output of empty\_set\_literal.py]

$ python empty_set_literal.py

set()

\end{lstlisting}

| empty_set_literal | Create an empty set using a literal |

empty_set = {*[]}

print(empty_set)