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Note

This documents the development version of NetworkX. Documentation for the current release can be found here.

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networkx.readwrite.adjlist.read_adjlist¶

read_adjlist(path, comments='#', delimiter=None, create_using=None, nodetype=None, encoding='utf-8')[source]¶

Read graph in adjacency list format from path.

Parameters

path (string or file) – Filename or file handle to read. Filenames ending in .gz or .bz2 will be uncompressed.
create_using (NetworkX graph constructor, optional (default=nx.Graph)) – Graph type to create. If graph instance, then cleared before populated.
nodetype (Python type, optional) – Convert nodes to this type.
comments (string, optional) – Marker for comment lines
delimiter (string, optional) – Separator for node labels. The default is whitespace.

Returns

G – The graph corresponding to the lines in adjacency list format.

Return type

NetworkX graph

Examples

>>> G = nx.path_graph(4)
>>> nx.write_adjlist(G, "test.adjlist")
>>> G = nx.read_adjlist("test.adjlist")

The path can be a filehandle or a string with the name of the file. If a filehandle is provided, it has to be opened in ‘rb’ mode.

>>> fh = open("test.adjlist", "rb")
>>> G = nx.read_adjlist(fh)

Filenames ending in .gz or .bz2 will be compressed.

>>> nx.write_adjlist(G, "test.adjlist.gz")
>>> G = nx.read_adjlist("test.adjlist.gz")

The optional nodetype is a function to convert node strings to nodetype.

For example

>>> G = nx.read_adjlist("test.adjlist", nodetype=int)

will attempt to convert all nodes to integer type.

Since nodes must be hashable, the function nodetype must return hashable types (e.g. int, float, str, frozenset - or tuples of those, etc.)

The optional create_using parameter indicates the type of NetworkX graph created. The default is nx.Graph, an undirected graph. To read the data as a directed graph use

>>> G = nx.read_adjlist("test.adjlist", create_using=nx.DiGraph)

Notes

This format does not store graph or node data.