YAML中的流映射表示鍵-值對的無序集合。它們也稱爲映射節點。請注意，密鑰應保持唯一。如果流映射結構中存在鍵的重複，則會生成錯誤。密鑰順序在序列化樹中生成。

Example

流映射結構的示例如下所示−

%YAML 1.1
paper:
   uuid: 8a8cbf60-e067-11e3-8b68-0800200c9a66
   name: On formally undecidable propositions of  Principia Mathematica and related systems I.
   author: Kurt Gödel.
tags:
   - tag:
      uuid: 98fb0d90-e067-11e3-8b68-0800200c9a66
      name: Mathematics
   - tag:
      uuid: 3f25f680-e068-11e3-8b68-0800200c9a66
      name: Logic

JSON格式的映射序列（無序列表）的輸出如下所示;

{
   "paper": {
      "uuid": "8a8cbf60-e067-11e3-8b68-0800200c9a66",
      "name": "On formally undecidable propositions of Principia Mathematica and related systems I.",
      "author": "Kurt Gödel."
   },
   "tags": [
      {
         "tag": {
            "uuid": "98fb0d90-e067-11e3-8b68-0800200c9a66",
            "name": "Mathematics"
         }
      },
      {
         "tag": {
            "uuid": "3f25f680-e068-11e3-8b68-0800200c9a66",
            "name": "Logic"
         }
      }
   ]
}

如果您觀察到如上所示的輸出，就會發現密鑰名在YAML映射結構中保持唯一。