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ee.Number.toUint8
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。
将输入值强制转换为无符号 8 位整数。
示例
代码编辑器 (JavaScript)
// Cast a number to unsigned 8-bit integer: [0, 255].
var number = ee.Number(100);
print('Number:', number);
var uint8Number = number.toUint8();
print('Number cast to uint8:', uint8Number);
/**
* Casting numbers to uint8 that are outside of its range and precision can
* modify the resulting value, note the behavior of the following scenarios.
*/
// A floating point number cast to uint8 loses decimal precision.
var float = ee.Number(1.7);
print('Floating point value:', float);
var floatToUint8 = float.toUint8();
print('Floating point value cast to uint8:', floatToUint8);
// A number greater than uint8 range max cast to uint8 becomes uint8 range max.
var UINT8_MAX = 255;
var outOfRangeHi = ee.Number(UINT8_MAX + 12345);
print('Greater than uint8 max:', outOfRangeHi);
var outOfRangeHiToUint8 = outOfRangeHi.toUint8();
print('Greater than uint8 max cast to uint8 becomes uint8 max:', outOfRangeHiToUint8);
// A number greater than uint8 range min cast to uint8 becomes uint8 range min.
var UINT8_MIN = 0;
var outOfRangeLo = ee.Number(UINT8_MIN - 12345);
print('Less than uint8 min:', outOfRangeLo);
var outOfRangeLoToUint8 = outOfRangeLo.toUint8();
print('Less than uint8 min cast to uint8 becomes uint8 min:', outOfRangeLoToUint8);
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)
# Cast a number to unsigned 8-bit integer: [0, 255].
number = ee.Number(100)
print('Number:', number.getInfo())
uint8_number = number.toUint8()
print('Number cast to uint8:', uint8_number.getInfo())
"""Casting numbers to uint8 that are outside of its range and precision can
modify the resulting value, note the behavior of the following scenarios.
"""
# A floating point number cast to uint8 loses decimal precision.
float_number = ee.Number(1.7)
print('Floating point value:', float_number.getInfo())
float_to_uint8 = float_number.toUint8()
print('Floating point value cast to uint8:', float_to_uint8.getInfo())
# A number greater than uint8 range max cast to uint8 becomes uint8 range max.
UINT8_MAX = 255
out_of_range_hi = ee.Number(UINT8_MAX + 12345)
print('Greater than uint8 max:', out_of_range_hi.getInfo())
out_of_range_hi_to_uint8 = out_of_range_hi.toUint8()
print('Greater than uint8 max cast to uint8 becomes uint8 max:',
out_of_range_hi_to_uint8.getInfo())
# A number greater than uint8 range min cast to uint8 becomes uint8 range min.
UINT8_MIN = 0
out_of_range_lo = ee.Number(UINT8_MIN - 12345)
print('Less than uint8 min:', out_of_range_lo.getInfo())
out_of_range_lo_to_uint8 = out_of_range_lo.toUint8()
print('Less than uint8 min cast to uint8 becomes uint8 min:',
out_of_range_lo_to_uint8.getInfo())
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\u003eNumber.toUint8()\u003c/code\u003e casts a number to an unsigned 8-bit integer, effectively converting it to a value within the range of 0 to 255.\u003c/p\u003e\n"],["\u003cp\u003eWhen applied to floating-point numbers, \u003ccode\u003etoUint8()\u003c/code\u003e truncates the decimal portion, resulting in a loss of precision.\u003c/p\u003e\n"],["\u003cp\u003eInput values exceeding the maximum value of an unsigned 8-bit integer (255) are converted to 255.\u003c/p\u003e\n"],["\u003cp\u003eInput values falling below the minimum value of an unsigned 8-bit integer (0) are converted to 0.\u003c/p\u003e\n"]]],[],null,["# ee.Number.toUint8\n\nCasts the input value to an unsigned 8-bit integer.\n\n\u003cbr /\u003e\n\n| Usage | Returns |\n|--------------------|---------|\n| Number.toUint8`()` | Number |\n\n| Argument | Type | Details |\n|---------------|--------|------------------|\n| this: `input` | Number | The input value. |\n\nExamples\n--------\n\n### Code Editor (JavaScript)\n\n```javascript\n// Cast a number to unsigned 8-bit integer: [0, 255].\nvar number = ee.Number(100);\nprint('Number:', number);\n\nvar uint8Number = number.toUint8();\nprint('Number cast to uint8:', uint8Number);\n\n\n/**\n * Casting numbers to uint8 that are outside of its range and precision can\n * modify the resulting value, note the behavior of the following scenarios.\n */\n\n// A floating point number cast to uint8 loses decimal precision.\nvar float = ee.Number(1.7);\nprint('Floating point value:', float);\n\nvar floatToUint8 = float.toUint8();\nprint('Floating point value cast to uint8:', floatToUint8);\n\n// A number greater than uint8 range max cast to uint8 becomes uint8 range max.\nvar UINT8_MAX = 255;\nvar outOfRangeHi = ee.Number(UINT8_MAX + 12345);\nprint('Greater than uint8 max:', outOfRangeHi);\n\nvar outOfRangeHiToUint8 = outOfRangeHi.toUint8();\nprint('Greater than uint8 max cast to uint8 becomes uint8 max:', outOfRangeHiToUint8);\n\n// A number greater than uint8 range min cast to uint8 becomes uint8 range min.\nvar UINT8_MIN = 0;\nvar outOfRangeLo = ee.Number(UINT8_MIN - 12345);\nprint('Less than uint8 min:', outOfRangeLo);\n\nvar outOfRangeLoToUint8 = outOfRangeLo.toUint8();\nprint('Less than uint8 min cast to uint8 becomes uint8 min:', outOfRangeLoToUint8);\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# Cast a number to unsigned 8-bit integer: [0, 255].\nnumber = ee.Number(100)\nprint('Number:', number.getInfo())\n\nuint8_number = number.toUint8()\nprint('Number cast to uint8:', uint8_number.getInfo())\n\n\n\"\"\"Casting numbers to uint8 that are outside of its range and precision can\nmodify the resulting value, note the behavior of the following scenarios.\n\"\"\"\n\n# A floating point number cast to uint8 loses decimal precision.\nfloat_number = ee.Number(1.7)\nprint('Floating point value:', float_number.getInfo())\n\nfloat_to_uint8 = float_number.toUint8()\nprint('Floating point value cast to uint8:', float_to_uint8.getInfo())\n\n# A number greater than uint8 range max cast to uint8 becomes uint8 range max.\nUINT8_MAX = 255\nout_of_range_hi = ee.Number(UINT8_MAX + 12345)\nprint('Greater than uint8 max:', out_of_range_hi.getInfo())\n\nout_of_range_hi_to_uint8 = out_of_range_hi.toUint8()\nprint('Greater than uint8 max cast to uint8 becomes uint8 max:',\n out_of_range_hi_to_uint8.getInfo())\n\n# A number greater than uint8 range min cast to uint8 becomes uint8 range min.\nUINT8_MIN = 0\nout_of_range_lo = ee.Number(UINT8_MIN - 12345)\nprint('Less than uint8 min:', out_of_range_lo.getInfo())\n\nout_of_range_lo_to_uint8 = out_of_range_lo.toUint8()\nprint('Less than uint8 min cast to uint8 becomes uint8 min:',\n out_of_range_lo_to_uint8.getInfo())\n```"]]