diff --git a/common_syntax/kotlin/List.kt b/common_syntax/kotlin/List.kt
new file mode 100644
index 0000000..5a35292
--- /dev/null
+++ b/common_syntax/kotlin/List.kt
@@ -0,0 +1,5 @@
+// Make a string groupBy by substring
+
+val inputList = listOf<String>("a","abc","xe", "df")
+// this is the map of length and values associated with condition of it.length
+inputList.groupBy{it.length}