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ee.Join.saveFirst
透過集合功能整理內容
你可以依據偏好儲存及分類內容。
傳回聯結，將第一個集合中的每個元素與第二個集合中的相符元素配對。第一個相符項目會以額外屬性的形式新增至結果。
| 用量 | 傳回 |
|---|
ee.Join.saveFirst(matchKey, ordering, ascending, measureKey, outer) | 加入 |
| 引數 | 類型 | 詳細資料 |
|---|
matchKey | 字串 | 用於儲存比對結果的屬性名稱。 |
ordering | 字串，預設值為空值 | 在選取第一個相符項目之前，要依據哪個屬性排序。 |
ascending | 布林值，預設值為 true | 排序是否為遞增。 |
measureKey | 字串，預設值為空值 | 用於儲存比對聯結條件測量的選用屬性名稱。 |
outer | 布林值，預設值為 false | 如果設為 true，結果會包含沒有相符項目的主要資料列。 |
除非另有註明，否則本頁面中的內容是採用創用 CC 姓名標示 4.0 授權，程式碼範例則為阿帕契 2.0 授權。詳情請參閱《Google Developers 網站政策》。Java 是 Oracle 和/或其關聯企業的註冊商標。
上次更新時間：2025-07-26 (世界標準時間)。
[null,null,["上次更新時間：2025-07-26 (世界標準時間)。"],[[["\u003cp\u003eThis function joins two collections by pairing elements based on matching property values.\u003c/p\u003e\n"],["\u003cp\u003eIt prioritizes the first match encountered and appends it as an additional property to the primary collection.\u003c/p\u003e\n"],["\u003cp\u003eUsers can specify sorting criteria for the matches using \u003ccode\u003eordering\u003c/code\u003e and \u003ccode\u003eascending\u003c/code\u003e parameters.\u003c/p\u003e\n"],["\u003cp\u003eOptionally, it allows saving the measure of the join condition and includes primary rows without matches if \u003ccode\u003eouter\u003c/code\u003e is true.\u003c/p\u003e\n"]]],["The `ee.Join.saveFirst` function creates a join between two collections, pairing each element from the first with its first matching element from the second. The matched element is stored as a new property, specified by `matchKey`. Matches can be sorted by `ordering` in `ascending` order before the first is selected. `measureKey` can be used to save the measurement of the join. Setting `outer` to true includes unmatched primary rows.\n"],null,["# ee.Join.saveFirst\n\nReturns a join that pairs each element from the first collection with a matching element from the second collection. The first match is added to the result as an additional property.\n\n\u003cbr /\u003e\n\n| Usage | Returns |\n|------------------------------------------------------------------------------------------|---------|\n| `ee.Join.saveFirst(matchKey, `*ordering* `, `*ascending* `, `*measureKey* `, `*outer*`)` | Join |\n\n| Argument | Type | Details |\n|--------------|-------------------------|----------------------------------------------------------------------------------------|\n| `matchKey` | String | The property name used to save the match. |\n| `ordering` | String, default: null | The property on which to sort the matches before selecting the first. |\n| `ascending` | Boolean, default: true | Whether the ordering is ascending. |\n| `measureKey` | String, default: null | An optional property name used to save the measure of the join condition on the match. |\n| `outer` | Boolean, default: false | If true, primary rows without matches will be included in the result. |"]]
