diff --git a/lib/jasmine-core/jasmine.js b/lib/jasmine-core/jasmine.js
index 57b5afe5..3df8d273 100644
--- a/lib/jasmine-core/jasmine.js
+++ b/lib/jasmine-core/jasmine.js
@@ -2572,8 +2572,8 @@ getJasmineRequireObj().matchersUtil = function(j$) {
     }
 
     var extraKeys = [];
-    for (var i in allKeys) {
-      if (!allKeys[i].match(/^[0-9]+$/)) {
+    for (var i = 0; i < allKeys.length; i++) {
+      if (!/^[0-9]+$/.test(allKeys[i])) {
         extraKeys.push(allKeys[i]);
       }
     }
diff --git a/src/core/matchers/matchersUtil.js b/src/core/matchers/matchersUtil.js
index 3aba3f0f..6516c33a 100644
--- a/src/core/matchers/matchersUtil.js
+++ b/src/core/matchers/matchersUtil.js
@@ -328,7 +328,7 @@ getJasmineRequireObj().matchersUtil = function(j$) {
 
     var extraKeys = [];
     for (var i = 0; i < allKeys.length; i++) {
-      if (!allKeys[i].match(/^[0-9]+$/)) {
+      if (!/^[0-9]+$/.test(allKeys[i])) {
         extraKeys.push(allKeys[i]);
       }
     }