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2025 年 4 月 15 日前註冊使用 Earth Engine 的非商業專案，都必須
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ee.Dictionary.get
透過集合功能整理內容
你可以依據偏好儲存及分類內容。
從字典中擷取具名值。如果字典不包含指定的鍵，則會傳回 defaultValue (除非為空值)。
| 用量 | 傳回 |
|---|
Dictionary.get(key, defaultValue) | 物件 |
| 引數 | 類型 | 詳細資料 |
|---|
這個：dictionary | 字典 | |
key | 字串 | |
defaultValue | 物件，預設值：null | |
範例
程式碼編輯器 (JavaScript)
// A dictionary (e.g. results of ee.Image.reduceRegion of an S2 image).
var dict = ee.Dictionary({
B1: 182,
B2: 219,
B3: 443
});
print('Value for "B1" key', dict.get('B1'));
// Set a default value for the case where the key does not exist.
print('Value for nonexistent "Band_1" key',
dict.get({key: 'Band_1', defaultValue: -9999}));
Python 設定
請參閱
Python 環境頁面，瞭解 Python API 和如何使用 geemap 進行互動式開發。
import ee
import geemap.core as geemap
Colab (Python)
# A dictionary (e.g. results of ee.Image.reduceRegion of an S2 image).
dic = ee.Dictionary({
'B1': 182,
'B2': 219,
'B3': 443
})
print('Value for "B1" key:', dic.get('B1').getInfo())
# Set a default value for the case where the key does not exist.
print('Value for nonexistent "Band_1" key:',
dic.get(**{'key': 'Band_1', 'defaultValue': -9999}).getInfo())
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\u003eThe \u003ccode\u003eDictionary.get()\u003c/code\u003e method extracts the value associated with a specified key from a dictionary.\u003c/p\u003e\n"],["\u003cp\u003eIf the key is not found in the dictionary, the method returns a user-defined default value.\u003c/p\u003e\n"],["\u003cp\u003eA null default value can be specified, resulting in a null return if the key is absent.\u003c/p\u003e\n"],["\u003cp\u003eThis function is applicable across different Earth Engine environments, including JavaScript, Python, and Colab.\u003c/p\u003e\n"]]],["The `get` method retrieves a value from a dictionary using a specified key. If the key exists, its corresponding value is returned. If the key is absent, a `defaultValue` is returned. The `defaultValue` can be customized, defaulting to `null` if not provided. Usage examples demonstrate retrieving existing values and setting default values for nonexistent keys, in both JavaScript and Python. The `get` method is applicable to dictionary objects.\n"],null,["# ee.Dictionary.get\n\nExtracts a named value from a dictionary. If the dictionary does not contain the given key, then defaultValue is returned, unless it is null.\n\n\u003cbr /\u003e\n\n| Usage | Returns |\n|-----------------------------------------|---------|\n| Dictionary.get`(key, `*defaultValue*`)` | Object |\n\n| Argument | Type | Details |\n|--------------------|-----------------------|---------|\n| this: `dictionary` | Dictionary | |\n| `key` | String | |\n| `defaultValue` | Object, default: null | |\n\nExamples\n--------\n\n### Code Editor (JavaScript)\n\n```javascript\n// A dictionary (e.g. results of ee.Image.reduceRegion of an S2 image).\nvar dict = ee.Dictionary({\n B1: 182,\n B2: 219,\n B3: 443\n});\n\nprint('Value for \"B1\" key', dict.get('B1'));\n\n// Set a default value for the case where the key does not exist.\nprint('Value for nonexistent \"Band_1\" key',\n dict.get({key: 'Band_1', defaultValue: -9999}));\n```\nPython setup\n\nSee the [Python Environment](/earth-engine/guides/python_install) page for information on the Python API and using\n`geemap` for interactive development. \n\n```python\nimport ee\nimport geemap.core as geemap\n```\n\n### Colab (Python)\n\n```python\n# A dictionary (e.g. results of ee.Image.reduceRegion of an S2 image).\ndic = ee.Dictionary({\n 'B1': 182,\n 'B2': 219,\n 'B3': 443\n})\n\nprint('Value for \"B1\" key:', dic.get('B1').getInfo())\n\n# Set a default value for the case where the key does not exist.\nprint('Value for nonexistent \"Band_1\" key:',\n dic.get(**{'key': 'Band_1', 'defaultValue': -9999}).getInfo())\n```"]]
