"""Read from and write to edgelists."""
from ..generators import empty_hypergraph
__all__ = [
"read_edgelist",
"write_edgelist",
"parse_edgelist",
]
[docs]def generate_edgelist(H, delimiter=" "):
"""
A helper function to generate a hyperedge list from a Hypergraph object.
Parameters
----------
H: Hypergraph object
The hypergraph of interest
delimiter: char, default: space (" ")
Specifies the delimiter between hyperedge members
Yields
-------
iterator of strings
Each entry is a line for the file to write.
"""
for id in H.edges:
e = H.edges.members(id)
yield delimiter.join(map(str, e))
[docs]def write_edgelist(H, path, delimiter=" ", encoding="utf-8"):
"""Create a file containing a hyperedge list from a Hypergraph object.
Parameters
----------
H: Hypergraph object
The hypergraph of interest
path: string
The path of the file to write to
delimiter: char, default: space (" ")
Specifies the delimiter between hyperedge members
encoding: string, default: "utf-8"
Encoding of the file
Examples
--------
>>> import xgi
>>> H = xgi.random_hypergraph(50, [0.01, 0.001])
>>> # xgi.write_edgelist(H, "test.csv", delimiter=",")
"""
with open(path, "wb") as file:
for line in generate_edgelist(H, delimiter):
line += "\n"
file.write(line.encode(encoding))
[docs]def read_edgelist(
path,
comments="#",
delimiter=None,
create_using=None,
nodetype=None,
encoding="utf-8",
):
"""Read a file containing a hyperedge list and
convert it to a Hypergraph object.
Parameters
----------
path: string
The path of the file to read from
comments: string, default: "#"
The token that denotes comments in the file
delimiter: char, default: space (" ")
Specifies the delimiter between hyperedge members
create_using : Hypergraph constructor, optional
The hypergraph object to add the data to, by default None
nodetype: type
type that the node labels will be cast to
encoding: string, default: "utf-8"
Encoding of the file
Returns
-------
Hypergraph object
The loaded hypergraph
See Also
--------
read_weighted_edgelist
Examples
--------
>>> import xgi
>>> # H = xgi.read_edgelist("test.csv", delimiter=",")
"""
with open(path, "rb") as file:
lines = (
line if isinstance(line, str) else line.decode(encoding) for line in file
)
return parse_edgelist(
lines,
comments=comments,
delimiter=delimiter,
create_using=create_using,
nodetype=nodetype,
)
[docs]def parse_edgelist(
lines, comments="#", delimiter=None, create_using=None, nodetype=None
):
"""
A helper function to read a iterable of strings containing a hyperedge list and
convert it to a Hypergraph object.
Parameters
----------
lines: iterable of strings
Lines where each line is an edge
comments: string, default: "#"
The token that denotes comments to ignore
delimiter: char, default: space (" ")
Specifies the delimiter between hyperedge members
create_using : Hypergraph constructor, optional
The hypergraph object to add the data to, by default None
nodetype: type
type that the node labels will be cast to
Returns
-------
Hypergraph object
The loaded hypergraph
"""
H = empty_hypergraph(create_using)
for line in lines:
if comments is not None:
p = line.find(comments)
if p >= 0:
line = line[:p]
if not line:
continue
edge = line.strip().split(delimiter)
if nodetype is not None:
try:
edge = [nodetype(node) for node in edge]
except ValueError as e:
raise TypeError(f"Failed to convert nodes to type {nodetype}.") from e
H.add_edge(edge)
return H