diff --git a/src/Encoder/Encoder.php b/src/Encoder/Encoder.php
index b31a5119..5df7b721 100644
--- a/src/Encoder/Encoder.php
+++ b/src/Encoder/Encoder.php
@@ -220,7 +220,7 @@ private function getEncodingParameters($data, EncodingParametersInterface $param
         } elseif ($parameters !== null && $parameters->getIncludePaths() !== null) {
             return $parameters;
         } else {
-            $schema       = $this->container->getSchema(is_array($data) ? $data[0] : $data);
+            $schema       = $this->container->getSchema(is_array($data) ? reset($data) : $data);
             $includePaths = $schema->getIncludePaths();
             $fieldSets    = $parameters === null ? null : $parameters->getFieldSets();
 
diff --git a/src/Encoder/Parser/Parser.php b/src/Encoder/Parser/Parser.php
index a2922ae6..4600f83b 100644
--- a/src/Encoder/Parser/Parser.php
+++ b/src/Encoder/Parser/Parser.php
@@ -131,7 +131,7 @@ private function parseData($data)
         } else {
             if (is_array($data) === true) {
                 $isOriginallyArrayed = true;
-                $schema = $this->container->getSchema($data[0]);
+                $schema = $this->container->getSchema(reset($data));
             } else {
                 $isOriginallyArrayed = false;
                 $schema = $this->container->getSchema($data);