I realize that matrix indexing has been addressed in various flavors, but I'm stumped and didn't find anything in the archives.  It's not clear if it is an igraph issue or a more general problem. Thanks in advance for your patience.

I am using igraph to read a gml file (http://www-personal.umich.edu/~mejn/netdata/football.zip
). The gml file contains vertex attributes (conference and team) that are provided as character/integer values.

I would like to build a matrix of dimension (length.team, length.conference) where the elements are zero except for 1's at the location of index [team, conference].

Here is a snippet of code that hopefully captures what I am trying to do:

original<-read.graph("./Data/football/football.gml", format="gml")
conf.list<- get.vertex.attribute(original, 'value', index=V(original))+1
team.list<- get.vertex.attribute(original, 'id', index=V(original))+1
temp<- matrix(0,115,12)
temp[team.list, conf.list]<-1

Unfortunately, temp[] is filled with 1's.

However, if I try:
c.list=c(1,3,5)
t.list=c(2,4,6)
temp[t.list,c.list]<-1

then things work as I would expect.  FWIW - I have tried as.integer(get.vertex.attribute(...)) with no luck.

Thanks for any suggestions.




*****************************************************
> original<-read.graph("./Data/football/football.gml", format="gml")
> conf.list<- get.vertex.attribute(original, 'value', index=V(original))+1
> team.list<- get.vertex.attribute(original, 'id', index=V(original))+1
> conf.list
  [1]  8  1  3  4  8  4  3  9  9  8  4 11  7  3  7  3  8 10  7  2 10  9  9  8 11  1  7 10 12  2  2  7  3  1  7  2  6
 [38]  1  7  3  4  8  6  7  5  1 12  3  5 12 11  9  4 12  7  2 10  5 12 11  3  7 10 11  3 10  5 12  9 11 10  7  4 12
 [75]  4  5 10  9  9  2  6  4  6 12  4  7  5 10 12  1  6  5  5  8  2 10 10 11  4  7  3  2  4  1  8  1  3  4  9  1  5
[112]  9  5 10 12
> team.list
  [1]   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27
 [28]  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54
 [55]  55  56  57  58  59  60  61  62  63  64  65  66  67  68  69  70  71  72  73  74  75  76  77  78  79  80  81
 [82]  82  83  84  85  86  87  88  89  90  91  92  93  94  95  96  97  98  99 100 101 102 103 104 105 106 107 108
[109] 109 110 111 112 113 114 115
> length(conf.list)
[1] 115
> length(team.list)
[1] 115
> temp<- matrix(0,115,12)
> r<-c(1,3,5)
> col<- c(2,4,6)
> temp[r,col]<-1
> temp[1:10,]
      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
 [1,]    0    1    0    1    0    1    0    0    0     0     0     0
 [2,]    0    0    0    0    0    0    0    0    0     0     0     0
 [3,]    0    1    0    1    0    1    0    0    0     0     0     0
 [4,]    0    0    0    0    0    0    0    0    0     0     0     0
 [5,]    0    1    0    1    0    1    0    0    0     0     0     0
 [6,]    0    0    0    0    0    0    0    0    0     0     0     0
 [7,]    0    0    0    0    0    0    0    0    0     0     0     0
 [8,]    0    0    0    0    0    0    0    0    0     0     0     0
 [9,]    0    0    0    0    0    0    0    0    0     0     0     0
[10,]    0    0    0    0    0    0    0    0    0     0     0     0
> temp[team.list,conf.list]<- 1
> temp[1:10,]
      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
 [1,]    1    1    1    1    1    1    1    1    1     1     1     1
 [2,]    1    1    1    1    1    1    1    1    1     1     1     1
 [3,]    1    1    1    1    1    1    1    1    1     1     1     1
 [4,]    1    1    1    1    1    1    1    1    1     1     1     1
 [5,]    1    1    1    1    1    1    1    1    1     1     1     1
 [6,]    1    1    1    1    1    1    1    1    1     1     1     1
 [7,]    1    1    1    1    1    1    1    1    1     1     1     1
 [8,]    1    1    1    1    1    1    1    1    1     1     1     1
 [9,]    1    1    1    1    1    1    1    1    1     1     1     1
[10,]    1    1    1    1    1    1    1    1    1     1     1     1
>
> ---------------------------------------------

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