The double bracket operator can be used on edge sequences, to print the meta-data (edge attributes) of the edges in the sequence.
# S3 method for igraph.es [[(x, ...)
An edge sequence.
Additional arguments, passed to
Another edge sequence, with metadata printing turned on. See details below.
Technically, when used with edge sequences, the double bracket operator does exactly the same as the single bracket operator, but the resulting edge sequence is printed differently: all attributes of the edges in the sequence are printed as well.
[.igraph.es for more about indexing edge sequences.
Other vertex and edge sequence operations: