Warning

This documents an unmaintained version of NetworkX. Please upgrade to a maintained version and see the current NetworkX documentation.

# Adjacency List¶

Read and write NetworkX graphs as adjacency lists.

Adjacency list format is useful for graphs without data associated with nodes or edges and for nodes that can be meaningfully represented as strings.

## Format¶

The adjacency list format consists of lines with node labels. The first label in a line is the source node. Further labels in the line are considered target nodes and are added to the graph along with an edge between the source node and target node.

The graph with edges a-b, a-c, d-e can be represented as the following adjacency list (anything following the # in a line is a comment):

```
a b c # source target target
d e
```

read_adjlist(path[, comments, delimiter, ...]) |
Read graph in adjacency list format from path. |

write_adjlist(G, path[, comments, ...]) |
Write graph G in single-line adjacency-list format to path. |

parse_adjlist(lines[, comments, delimiter, ...]) |
Parse lines of a graph adjacency list representation. |

generate_adjlist(G[, delimiter]) |
Generate a single line of the graph G in adjacency list format. |