公告：所有在
2025 年 4 月 15 日之前注册使用 Earth Engine 的非商业项目都必须
验证是否符合非商业性质的资格条件，才能继续使用 Earth Engine。
ee.Dictionary.evaluate
使用集合让一切井井有条
根据您的偏好保存内容并对其进行分类。
以异步方式从服务器检索此对象的值，并将其传递给所提供的回调函数。
| 用法 | 返回 |
|---|
Dictionary.evaluate(callback) | |
| 参数 | 类型 | 详细信息 |
|---|
此：computedobject | ComputedObject | ComputedObject 实例。 |
callback | 函数 | 一种函数，形式为 function(success, failure)，在服务器返回答案时调用。如果请求成功，success 实参将包含评估结果。如果请求失败，失败实参将包含错误消息。 |
示例
代码编辑器 (JavaScript)
// A dictionary (e.g. results of ee.Image.reduceRegion of an S2 image).
var dictServer = ee.Dictionary({
B1: 182,
B2: 219,
B3: 443
});
// Use evaluate to transfer server-side dictionary to the client.
dictServer.evaluate(function(dictClient) {
print('Client-side dot notation to access "B1" value', dictClient.B1);
print('Client-side bracket notation to access "B1" value', dictClient['B1']);
print('Client-side operations to print all key-value pairs');
Object.keys(dictClient).forEach(function(key) {
print(' ' + key + ': ' + dictClient[key]);
});
});
Python 设置
如需了解 Python API 和如何使用 geemap 进行交互式开发，请参阅
Python 环境页面。
import ee
import geemap.core as geemap
Colab (Python)
# The Earth Engine Python client library does not have an evaluate method for
# asynchronous evaluation of ee.Dictionary objects.
# Use ee.Dictionary.getInfo() instead.
如未另行说明，那么本页面中的内容已根据知识共享署名 4.0 许可获得了许可，并且代码示例已根据 Apache 2.0 许可获得了许可。有关详情，请参阅 Google 开发者网站政策。Java 是 Oracle 和/或其关联公司的注册商标。
最后更新时间 (UTC)：2025-07-26。
[null,null,["最后更新时间 (UTC)：2025-07-26。"],[[["\u003cp\u003e\u003ccode\u003eDictionary.evaluate()\u003c/code\u003e asynchronously retrieves the value of a server-side ComputedObject (like a dictionary) and passes it to a callback function.\u003c/p\u003e\n"],["\u003cp\u003eThe provided callback function handles the server response, receiving the evaluated result on success or an error message on failure.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eDictionary.evaluate()\u003c/code\u003e enables client-side access and manipulation of the server-side dictionary data using standard JavaScript operations.\u003c/p\u003e\n"],["\u003cp\u003eWhile the JavaScript API uses \u003ccode\u003eDictionary.evaluate()\u003c/code\u003e, the Python API leverages \u003ccode\u003eDictionary.getInfo()\u003c/code\u003e for synchronous retrieval of dictionary values.\u003c/p\u003e\n"]]],["The `evaluate` method asynchronously retrieves a `ComputedObject`'s value from the server and provides it to a callback function. The callback receives a success argument with the result or a failure argument with an error message. It's demonstrated with a dictionary example where server-side data is transferred to the client-side. In Python, `getInfo()` is used instead of `evaluate` for `ee.Dictionary` objects. The provided table details the usage, argument types, and their specifics.\n"],null,["# ee.Dictionary.evaluate\n\n\u003cbr /\u003e\n\nAsynchronously retrieves the value of this object from the server and passes it to the provided callback function.\n\n\u003cbr /\u003e\n\n| Usage | Returns |\n|---------------------------------|---------|\n| Dictionary.evaluate`(callback)` | |\n\n| Argument | Type | Details |\n|------------------------|----------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| this: `computedobject` | ComputedObject | The ComputedObject instance. |\n| `callback` | Function | A function of the form function(success, failure), called when the server returns an answer. If the request succeeded, the success argument contains the evaluated result. If the request failed, the failure argument will contains an error message. |\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 dictServer = ee.Dictionary({\n B1: 182,\n B2: 219,\n B3: 443\n});\n\n// Use evaluate to transfer server-side dictionary to the client.\ndictServer.evaluate(function(dictClient) {\n print('Client-side dot notation to access \"B1\" value', dictClient.B1);\n print('Client-side bracket notation to access \"B1\" value', dictClient['B1']);\n\n print('Client-side operations to print all key-value pairs');\n Object.keys(dictClient).forEach(function(key) {\n print(' ' + key + ': ' + dictClient[key]);\n });\n});\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# The Earth Engine Python client library does not have an evaluate method for\n# asynchronous evaluation of ee.Dictionary objects.\n# Use ee.Dictionary.getInfo() instead.\n```"]]
