1 files changed, 34 insertions, 0 deletions
diff --git a/ios/WALT/NSArray+Extensions.m b/ios/WALT/NSArray+Extensions.m
new file mode 100644
index 0000000..2217bc4
--- /dev/null
+++ b/ios/WALT/NSArray+Extensions.m
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import "NSArray+Extensions.h"
+
+@implementation NSArray (WALTExtensions)
+- (NSNumber *)medianValue {
+  NSArray<NSNumber *> *sorted = [self sortedArrayUsingSelector:@selector(compare:)];
+  const NSUInteger count = sorted.count;
+  if (count == 0) {
+    return nil;
+  }
+  
+  if (count % 2) {
+    return [sorted objectAtIndex:count / 2];
+  } else {
+    return [NSNumber numberWithDouble:0.5 * ([sorted objectAtIndex:count / 2].doubleValue +
+                                             [sorted objectAtIndex:count / 2 - 1].doubleValue)];
+  }
+}
+@end