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ee.String.evaluate
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Recupera in modo asincrono il valore di questo oggetto dal server e lo passa alla funzione di callback fornita.
| Utilizzo | Resi |
|---|
String.evaluate(callback) | |
| Argomento | Tipo | Dettagli |
|---|
questo: computedobject | ComputedObject | L'istanza ComputedObject. |
callback | Funzione | Una funzione del modulo function(success, failure), chiamata quando il server restituisce una risposta. Se la richiesta è riuscita, l'argomento success contiene il risultato valutato. Se la richiesta non è riuscita, l'argomento failure conterrà un messaggio di errore. |
Esempi
Editor di codice (JavaScript)
/**
* WARNING: this function transfers data from Earth Engine servers to the
* client. Doing so can negatively affect request processing and client
* performance. Server-side options should be used whenever possible.
* Learn more about the distinction between server and client:
* https://developers.google.com/earth-engine/guides/client_server
*/
// A server-side ee.String object fetched from a feature property.
var stringServer = ee.Feature(null, {lc: 'grassland'}).getString('lc');
// Use evaluate to transfer server-side string to client for use in ui.Label.
stringServer.evaluate(function(stringClient) {
print('Client-side primitive data type', typeof stringClient); // string
print('Client-side string', stringClient); // grassland
print('Client-side string used in ui.Label',
ui.Label('Land cover: ' + stringClient)); // Land cover: grassland
});
Configurazione di Python
Consulta la pagina
Ambiente Python per informazioni sull'API Python e sull'utilizzo di
geemap per lo sviluppo interattivo.
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.String objects.
# Use ee.String.getInfo() instead.
Salvo quando diversamente specificato, i contenuti di questa pagina sono concessi in base alla licenza Creative Commons Attribution 4.0, mentre gli esempi di codice sono concessi in base alla licenza Apache 2.0. Per ulteriori dettagli, consulta le norme del sito di Google Developers. Java è un marchio registrato di Oracle e/o delle sue consociate.
Ultimo aggiornamento 2025-07-26 UTC.
[null,null,["Ultimo aggiornamento 2025-07-26 UTC."],[[["\u003cp\u003e\u003ccode\u003eevaluate()\u003c/code\u003e retrieves the value of a server-side ComputedObject (like an \u003ccode\u003eee.String\u003c/code\u003e) and passes it to a client-side callback function.\u003c/p\u003e\n"],["\u003cp\u003eThis function is primarily used for transferring data from the Earth Engine servers to the client for tasks like displaying information in UI elements.\u003c/p\u003e\n"],["\u003cp\u003eExcessive use of \u003ccode\u003eevaluate()\u003c/code\u003e can impact performance and should be used judiciously, opting for server-side operations whenever possible.\u003c/p\u003e\n"],["\u003cp\u003eThe Python client library uses \u003ccode\u003egetInfo()\u003c/code\u003e for asynchronous evaluation instead of \u003ccode\u003eevaluate()\u003c/code\u003e.\u003c/p\u003e\n"]]],[],null,["# ee.String.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| String.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/**\n * WARNING: this function transfers data from Earth Engine servers to the\n * client. Doing so can negatively affect request processing and client\n * performance. Server-side options should be used whenever possible.\n * Learn more about the distinction between server and client:\n * https://developers.google.com/earth-engine/guides/client_server\n */\n\n// A server-side ee.String object fetched from a feature property.\nvar stringServer = ee.Feature(null, {lc: 'grassland'}).getString('lc');\n\n// Use evaluate to transfer server-side string to client for use in ui.Label.\nstringServer.evaluate(function(stringClient) {\n print('Client-side primitive data type', typeof stringClient); // string\n print('Client-side string', stringClient); // grassland\n print('Client-side string used in ui.Label',\n ui.Label('Land cover: ' + stringClient)); // Land cover: grassland\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.String objects.\n# Use ee.String.getInfo() instead.\n```"]]
