ee.Number.toUint8

将输入值强制转换为无符号 8 位整数。

用法返回
Number.toUint8()数字
参数类型详细信息
此：input数字输入值。

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())