ee.Number.expression

Menghitung ekspresi numerik.

Penggunaan	Hasil
ee.Number.expression(expression, vars)	Angka

Argumen	Jenis	Detail
expression	String	String ekspresi matematika yang akan dievaluasi. Selain operator aritmatika, boolean, dan relasional standar, ekspresi juga mendukung fungsi apa pun di Number, operator '.' untuk mengekstrak elemen turunan dari kamus 'vars', dan konstanta matematika Math.PI dan Math.E.
vars	Kamus, default: null	Kamus nilai bernama yang dapat digunakan dalam ekspresi.

Contoh

Code Editor (JavaScript)

// A dictionary of variables to use in expression.
var variables = {x: 5, y: 10};

// Arithmetic operators.
print('x + y',
      ee.Number.expression('x + y', variables));
print('x - y',
      ee.Number.expression('x - y', variables));
print('x * y',
      ee.Number.expression('x * y', variables));
print('x / y',
      ee.Number.expression('x / y', variables));
print('x ** y',
      ee.Number.expression('x ** y', variables));
print('x % y',
      ee.Number.expression('x % y', variables));

// Logical operators.
print('x || y',
      ee.Number.expression('x || y', variables));
print('x && y',
      ee.Number.expression('x && y', variables));
print('!(x)',
      ee.Number.expression('!(x)', variables));

// Relational operators.
print('x > y',
      ee.Number.expression('x > y', variables));
print('x >= y',
      ee.Number.expression('x >= y', variables));
print('x < y',
      ee.Number.expression('x < y', variables));
print('x <= y',
      ee.Number.expression('x <= y', variables));
print('x == y',
      ee.Number.expression('x == y', variables));
print('x != y',
      ee.Number.expression('x != y', variables));

// Conditional (ternary) operator.
print('(x < y) ? 100 : 1000)',
      ee.Number.expression('(x < y) ? 100 : 1000', variables));

// Constants in the expression.
print('100 * (x + y)',
      ee.Number.expression('100 * (x + y)', variables));

// JavaScript Math constants.
print('Math.PI',
      ee.Number.expression('Math.PI', null));
print('Math.E',
      ee.Number.expression('Math.E', null));

// Dot notation to call on child elements.
print('Use dot notation to call on child elements',
      ee.Number.expression('vals.x * vals.y', {vals: variables}));

// ee.Number functions.
print('Use ee.Number add: add(x, y)',
      ee.Number.expression('add(x, y)', variables));
print('Use ee.Number add and subtract: subtract(add(x, y), 5)',
      ee.Number.expression('subtract(add(x, y), 5)', variables));

Penyiapan Python

Lihat halaman Lingkungan Python untuk mengetahui informasi tentang Python API dan penggunaan geemap untuk pengembangan interaktif.

import ee
import geemap.core as geemap

Colab (Python)

# A dictionary of variables to use in expression.
variables = {'x': 5, 'y': 10}

# Arithmetic operators.
display('x + y:',
        ee.Number.expression('x + y', variables))
display('x - y:',
        ee.Number.expression('x - y', variables))
display('x * y:',
        ee.Number.expression('x * y', variables))
display('x / y:',
        ee.Number.expression('x / y', variables))
display('x ** y:',
        ee.Number.expression('x ** y', variables))
display('x % y:',
        ee.Number.expression('x % y', variables))

# Logical operators.
display('x || y:',
        ee.Number.expression('x || y', variables))
display('x && y:',
        ee.Number.expression('x && y', variables))
display('!(x):',
        ee.Number.expression('!(x)', variables))

# Relational operators.
display('x > y:',
        ee.Number.expression('x > y', variables))
display('x >= y:',
        ee.Number.expression('x >= y', variables))
display('x < y:',
        ee.Number.expression('x < y', variables))
display('x <= y:',
        ee.Number.expression('x <= y', variables))
display('x == y:',
        ee.Number.expression('x == y', variables))
display('x != y:',
        ee.Number.expression('x != y', variables))

# Conditional JavaScript (ternary) operator.
display('(x < y) ? 100 : 1000):',
        ee.Number.expression('(x < y) ? 100 : 1000', variables))

# Constants in the expression.
display('100 * (x + y):',
        ee.Number.expression('100 * (x + y)', variables))

# JavaScript Math constants.
display('Math.PI:',
        ee.Number.expression('Math.PI', None))
display('Math.E:',
        ee.Number.expression('Math.E', None))

# Dot notation to call on child elements.
display('Use dot notation to call on child elements:',
        ee.Number.expression('vals.x * vals.y', {'vals': variables}))

# ee.Number functions.
display('Use ee.Number add. add(x, y):',
        ee.Number.expression('add(x, y)', variables))
display('Use ee.Number add and subtract. subtract(add(x, y), 5):',
        ee.Number.expression('subtract(add(x, y), 5)', variables))