From f396d586632510e6020698bbd54c8fd4ff88628e Mon Sep 17 00:00:00 2001
From: metheglin <pigmybank@gmail.com>
Date: Tue, 13 Dec 2016 19:11:56 +0900
Subject: [PATCH] Check existence of the index of array.

---
 lib/histogram.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/histogram.rb b/lib/histogram.rb
index eb095cb..546d3f1 100644
--- a/lib/histogram.rb
+++ b/lib/histogram.rb
@@ -343,7 +343,7 @@ def histogram(*args)
           if index == bins
             index -= 1
           end
-          _freqs[index] += height
+          _freqs[index] += height if _freqs[index]
         end
         _freqs
       end