# Source code for networkx.algorithms.operators.unary

```"""Unary operations on graphs"""
import networkx as nx

__all__ = ["complement", "reverse"]

[docs]
@nx._dispatchable(returns_graph=True)
def complement(G):
"""Returns the graph complement of G.

Parameters
----------
G : graph
A NetworkX graph

Returns
-------
GC : A new graph.

Notes
-----
Note that `complement` does not create self-loops and also
does not produce parallel edges for MultiGraphs.

Graph, node, and edge data are not propagated to the new graph.

Examples
--------
>>> G = nx.Graph([(1, 2), (1, 3), (2, 3), (3, 4), (3, 5)])
>>> G_complement = nx.complement(G)
>>> G_complement.edges()  # This shows the edges of the complemented graph
EdgeView([(1, 4), (1, 5), (2, 4), (2, 5), (4, 5)])

"""
R = G.__class__()
((n, n2) for n, nbrs in G.adjacency() for n2 in G if n2 not in nbrs if n != n2)
)
return R

[docs]
@nx._dispatchable(returns_graph=True)
def reverse(G, copy=True):
"""Returns the reverse directed graph of G.

Parameters
----------
G : directed graph
A NetworkX directed graph
copy : bool
If True, then a new graph is returned. If False, then the graph is
reversed in place.

Returns
-------
H : directed graph
The reversed G.

Raises
------
NetworkXError
If graph is undirected.

Examples
--------
>>> G = nx.DiGraph([(1, 2), (1, 3), (2, 3), (3, 4), (3, 5)])
>>> G_reversed = nx.reverse(G)
>>> G_reversed.edges()
OutEdgeView([(2, 1), (3, 1), (3, 2), (4, 3), (5, 3)])

"""
if not G.is_directed():
raise nx.NetworkXError("Cannot reverse an undirected graph.")
else:
return G.reverse(copy=copy)

```