ee.Number.toUint8

Truyền giá trị đầu vào thành số nguyên 8 bit không dấu.

Cách sử dụng	Giá trị trả về
Number.toUint8()	Số

Đối số	Loại	Thông tin chi tiết
this: input	Số	Giá trị đầu vào.

Ví dụ

Trình soạn thảo mã (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);

Thiết lập Python

Hãy xem trang Môi trường Python để biết thông tin về API Python và cách sử dụng geemap cho quá trình phát triển tương tác.

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())