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## [igraph] reordering the vertex sequence

 From: Lin Freeman Subject: [igraph] reordering the vertex sequence Date: Sat, 28 May 2011 07:12:45 -0700

Suppose I have a data set, "zach" in an ncol form with weights:

2                   1                   4
3                   1                   5
3                   2                   6
4                   1                   3
4                   2                   3
4                   3                   3
5                   1                   3
6                   1                   3
7                   1                   3
7                   5                   2
7                   6                   5
8                   1                   2
8                   2                   4
8                   3                   4
8                   4                   3
9                   1                   2
9                   3                   5
10                   3                   1
11                   1                   2
11                   5                   3
11                   6                   3
12                   1                   3
13                   1                   1
13                   4                   3
14                   1                   3
14                   2                   5
14                   3                   3
14                   4                   3
17                   6                   3
17                   7                   3
18                   1                   2
18                   2                   1
20                   1                   2
20                   2                   2
22                   1                   2
22                   2                   2
26                  24                   5
26                  25                   2
28                   3                   2
28                  24                   4
28                  25                   3
29                   3                   2
30                  24                   3
30                  27                   4
31                   2                   2
31                   9                   3
32                   1                   2
32                  25                   2
32                  26                   7
32                  29                   2
33                   3                   2
33                   9                   3
33                  15                   3
33                  16                   3
33                  19                   1
33                  21                   3
33                  23                   2
33                  24                   5
33                  30                   4
33                  31                   3
33                  32                   4
34                   9                   4
34                  10                   2
34                  14                   3
34                  15                   2
34                  16                   4
34                  19                   2
34                  20                   1
34                  21                   1
34                  23                   3
34                  24                   4
34                  27                   2
34                  28                   4
34                  29                   2
34                  30                   2
34                  31                   3
34                  32                   4
34                  33                   5

I can read it into igraph as follows:

> G <- read.graph("zach.txt", format="ncol", weights=V(G)\$weight

But, then, the vertex sequence is:

> V(G)
Vertex sequence:
[1] "2"  "1"  "3"  "4"  "5"  "6"  "7"  "8"  "9"  "10" "11" "12" "13" "14" "17"
[16] "18" "20" "22" "26" "24" "25" "28" "29" "30" "27" "31" "32" "33" "15" "16"
[31] "19" "21" "23" "34"

However, I want the vertices in G to be arranged in the natural order according to their labels, "1"  "2"  etc.
That way I can interpret the memberships produced by a community finding algorithm easily.

How can I get the vertices into the order I want?

Thank you,

Lin Freeman

--
Linton C. Freeman
Institute for Mathematical Behavioral Sciences and
Department of Sociology
School of Social Sciences  SSPA 2143
University of California
Irvine, CA 92697-5100

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