Arbitrary row/column selection for NMatrix
Arbitrary row/column selection for NMatrix. Allows you to do selections like:
x.col([0,2]).row(y =~ 'setosa')
Works with dense and sparse matrix types.
gem install nmatrix-rowcol
require 'nmatrix/rowcol'm = NMatrix.indgen [3,3]# [ [0, 1, 2]# [3, 4, 5]# [6, 7, 8] ]m.row [0,2]# [ [0, 1, 2]# [6, 7, 8] ]m.row m.sum(1) > 6# [ [3, 4, 5]# [6, 7, 8] ]m.col [0,2]# [ [0, 2]# [3, 5]# [6, 8] ]m.col m.sum(0) > 12# [ [2]# [5]# [8] ]m.row([0,2]).col([0,2])# [ [0, 2]# [6, 8] ]m.col [2,0,1] # re-arrange columns# [ [2, 0, 1]# [5, 3, 4]# [8, 6, 7] ]m.row m.rows.times.to_a.sample(2) # random row samples# [ [6, 7, 8]# [0, 1, 2] ]
MIT