R igraph manual pages

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Reading foreign file formats

Description

The read_graph function is able to read graphs in various representations from a file, or from a http connection. Currently some simple formats are supported.

Usage

read_graph(file, format = c("edgelist", "pajek", "ncol", "lgl", "graphml",
  "dimacs", "graphdb", "gml", "dl"), ...)

Arguments

file

The connection to read from. This can be a local file, or a http or ftp connection. It can also be a character string with the file name or URI.

format

Character constant giving the file format. Right now as_edgelist, pajek, graphml, gml, ncol, lgl, dimacs and graphdb are supported, the default is edgelist. As of igraph 0.4 this argument is case insensitive.

...

Additional arguments, see below.

Details

The read_graph function may have additional arguments depending on the file format (the format argument). See the details separately for each file format, below.

Value

A graph object.

Edge list format

This format is a simple text file with numeric vertex ids defining the edges. There is no need to have newline characters between the edges, a simple space will also do.

Additional arguments:

n

The number of vertices in the graph. If it is smaller than or equal to the largest integer in the file, then it is ignored; so it is safe to set it to zero (the default).

directed

Logical scalar, whether to create a directed graph. The default value is TRUE.

Author(s)

Gabor Csardi csardi.gabor@gmail.com

See Also

write_graph


[Package igraph version 1.0.0 Index]