Merge pull request #22 from mrkn/fix_hist

histogram: Fill weights array by zeros before putting weight values

Author: mrkn

ext/enumerable/statistics/extension/statistics.c

@@ -2284,7 +2284,7 @@ ary_histogram(int argc, VALUE *argv, VALUE ary)
 {
   VALUE arg0, opts, edge, weights;
   int left_p;
-  long nbins;
+  long nbins, nweights, i;
 
   rb_scan_args(argc, argv, "01:", &arg0, &opts);
   if (NIL_P(arg0)) {
@@ -2296,7 +2296,13 @@ ary_histogram(int argc, VALUE *argv, VALUE ary)
   left_p = opt_closed_left_p(opts);
 
   edge = ary_histogram_calculate_edge(ary, nbins, left_p);
-  weights = rb_ary_new_capa(RARRAY_LEN(edge) - 1);
+
+  nweights = RARRAY_LEN(edge) - 1;
+  weights = rb_ary_new_capa(nweights);
+  for (i = 0; i < nweights; ++i) {
+    rb_ary_store(weights, i, INT2FIX(0));
+  }
+
   histogram_weights_push_values(weights, edge, ary, left_p);
 
   return rb_struct_new(cHistogram, edge, weights,

spec/histogram/array_spec.rb

@@ -4,8 +4,9 @@
 RSpec.describe Array, '#histogram' do
   let(:ary) { [] }
   let(:args) { [] }
+  let(:kwargs) { {} }
 
-  subject(:histogram) { ary.histogram(*args) }
+  subject(:histogram) { ary.histogram(*args, **kwargs) }
 
   with_array [] do
     context 'default' do
@@ -18,7 +19,7 @@
     end
 
     context 'closed: :right' do
-      let(:args) { [{closed: :right}] }
+      let(:kwargs) { {closed: :right} }
 
       specify do
         expect(histogram.edge).to eq([0.0])
@@ -51,6 +52,19 @@
     end
   end
 
+  with_array [1, 2] do
+    context 'closed: :left' do
+      let(:kwargs) { {closed: :left} }
+
+      specify do
+        expect(histogram.edge).to eq([1.0, 1.5, 2.0, 2.5])
+        expect(histogram.weights).to eq([1, 0, 1])
+        expect(histogram.closed).to eq(:left)
+        expect(histogram.density?).to eq(false)
+      end
+    end
+  end
+
   with_array [1, 2, 3, 4, 5, 6, 7, 8, 9] do
     context 'default' do
       specify do
@@ -62,7 +76,7 @@
     end
 
     context 'closed: :right' do
-      let(:args) { [{closed: :right}] }
+      let(:kwargs) { {closed: :right} }
 
       specify do
         expect(histogram.edge).to eq([0.0, 2.0, 4.0, 6.0, 8.0, 10.0])
@@ -108,7 +122,7 @@
     end
 
     context "closed: :right" do
-      let(:args) { [{closed: :right}] }
+      let(:kwargs) { {closed: :right} }
 
       specify do
         expect(histogram.edge).to eq([-4.0, -3.5, -3.0, -2.5, -2.0, -1.5,