A connection to a graph file. When provided as a path to a file, it will read the file from disk. Files starting with http://, https://, ftp://, or ftps:// will be automatically downloaded.

The type of file to be imported. Options are: gml (GML), sif (SIF), edges (a .edges file), and mtx (MatrixMarket format). If not supplied, the type of graph file will be inferred by its file extension.

For edges files, a vector of attribute names beyond the from and to data columns can be provided in the order they appear in the input data file.

For edges files, this is a string of column types for any attribute columns provided for edges_extra_attr_names. This string representation is where each character represents each of the extra columns of data and the mappings are: c -> character, i -> integer, n -> number, d -> double, l -> logical, D -> date, T -> date time, t -> time, ? -> guess, or _/-, which skips the column.

An optional string for labeling the graph object.

The theme (i.e., collection of graph, node, and edge global graph attributes) to use for this graph. The default theme is called default; there are hierarchical layout themes called lr, tb, rl, and bt (these operate from left-to-right, top-to-bottom, right-to-left, and bottom-to-top); and, for larger graphs, the fdp theme provides a force directed layout. If this is set to NULL then no global graph attributes will be applied to the graph upon creation.

An option to write incremental backups of changing graph states to disk. If TRUE, a subdirectory within the working directory will be created and used to store RDS files. The default value is FALSE so one has to opt in to use this functionality.

An option to display messages primarily concerned with changes in graph selections. By default, this is FALSE.