ruby - phone-number

ruby/phone-number/phone_number.rb

@@ -0,0 +1,19 @@
+class PhoneNumber
+  def self.clean(number)
+    number.gsub!(/[^0-9]/, '')
+
+    if number.length < 10 or number.length > 11
+      nil
+    elsif number.length == 11
+      if number[0] == "1"
+        number.slice(1, number.length)
+      else
+        nil
+      end
+    elsif ["0", "1"].include?(number[0]) or ["0", "1"].include?(number[3])
+      nil
+    else
+      number
+    end
+  end
+end