Re: [igraph] Extra vertex being read from edgelist

[Tamás Nepusz]

Hi

igraph edgelist files use zero-based vertex indices, so your edgelist file contains 1134 vertices since the highest vertex ID in the file is 1133. Subtract 1 from every edge ID  in the file and you should be okay. (However, note that vertex indices in R start from 1, so if you have a vertex with ID=X in your file, this will be vertex X+1 in R).

In case you wonder why edgelist files are zero-based: this is for sake of compatibility with edgelist files created from the raw C API of igraph or from igraph’s Python interface because those are zero-based.

-- 

T.

On Tuesday, 19 November 2013 at 16:00, Prithwiraj MUKHERJEE wrote:

Hi

I have attached an edgelist file "email_edges.txt". The graph has 1133 vertices. I am reading it as

G<-read.graph("email_edges.txt", format="edgelist")

On checking the graph, it has 1134 vertices (one extra vertex). Is there something I am missing?

I am using igraph's latest version (i updated it today) on R 2.15.3 (64 bit) for Windows 7.

Regards

Prithwiraj

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Attachments:

- email_edges.txt