List,
given an arbitrary n x m boolean matrix, say
[,1] [,2] [,3] [,4] [,5]
[1,] FALSE FALSE FALSE FALSE FALSE
[2,] FALSE FALSE TRUE FALSE FALSE
[3,] FALSE FALSE FALSE FALSE FALSE
[4,] FALSE FALSE FALSE TRUE TRUE
I have the TRUE entries (indexes) of each column, in a list
[[1]]
integer(0)
[[2]]
integer(0)
[[3]]
[1] 2
[[4]]
[1] 4
[[5]]
[1] 4
How can I, from this list, efficiently obtain the TRUE entries of each
row, in this case
[[1]]
integer(0)
[[2]]
[1] 3
[[3]]
integer(0)
[[4]]
[1] 4 5
without constructing the n x m boolean matrix?
--
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
8333081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de
http://www.52north.org/geostatistics [email protected]
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