dataset.rb in svmkit-0.7.1

- old
+ new

@@ -1,7 +1,9 @@
 # frozen_string_literal: true
 
+require 'csv'
+
 module SVMKit
   # Module for loading and saving a dataset file.
   module Dataset
     class << self
       # Load a dataset with the libsvm file format into Numo::NArray.
@@ -14,15 +16,15 @@
       #   and (n_samples) vector for labels or target values.
       def load_libsvm_file(filename, zero_based: false)
         ftvecs = []
         labels = []
         n_features = 0
-        File.read(filename).split("\n").each do |line|
+        CSV.foreach(filename, col_sep: "\s", headers: false) do |line|
           label, ftvec, max_idx = parse_libsvm_line(line, zero_based)
           labels.push(label)
           ftvecs.push(ftvec)
-          n_features = [n_features, max_idx].max
+          n_features = max_idx if n_features < max_idx
         end
         [convert_to_matrix(ftvecs, n_features), Numo::NArray.asarray(labels)]
       end
 
       # Dump the dataset with the libsvm file format.
@@ -46,19 +48,20 @@
       end
 
       private
 
       def parse_libsvm_line(line, zero_based)
-        tokens = line.split
-        label = parse_label(tokens.shift)
-        ftvec = tokens.map do |el|
+        label = parse_label(line.shift)
+        adj_idx = zero_based == false ? 1 : 0
+        max_idx = -1
+        ftvec = []
+        while (el = line.shift)
           idx, val = el.split(':')
-          idx = idx.to_i - (zero_based == false ? 1 : 0)
+          idx = idx.to_i - adj_idx
           val = val.to_i.to_s == val ? val.to_i : val.to_f
-          [idx, val]
+          max_idx = idx if max_idx < idx
+          ftvec.push([idx, val])
         end
-        max_idx = ftvec.map { |el| el[0] }.max
-        max_idx ||= 0
         [label, ftvec, max_idx]
       end
 
       def parse_label(label)
         lbl_arr = label.split(',').map { |lbl| lbl.to_i.to_s == lbl ? lbl.to_i : lbl.to_f }