pxt-calliope/olddocs/js/number.md
2017-03-07 10:17:01 -08:00

2.7 KiB

Number

An integer number.

@parent javascript/language

A Number is an integer such as 42 or -42. More precisely, a Number is a signed 32-bit integer (two's complement).

Declare a number variable

Use the var statement and the assignment operator := to declare a local number variable. Like this:

let number1 = 2
let number2 = 2

To declare a global number variable, see global variables.

Arithmetic operators

The following arithmetic operators work on numbers and return a Number:

  • addition: 1 + 3
  • subtraction: 1 - 3
  • multiplication: 3 * 2
  • integer division: 7 / 3
  • modulo is available through the math library

Relational operators

The following relational operators work on numbers and return a Boolean:

  • equality: (3 + 1) = 4
  • inequality: 3 != 4
  • less or equal than: 3 <= 4
  • less than: 3 < 4
  • greater or equal than : 4 >= 3
  • greater than: 4 > 3

Show number

The show number function displays a number on the LED screen. For example, this code displays the number 42:

basic.showNumber(42, 100)

Functions that return a number

Some functions return a number, which you can store in a variable. For example the following code gets the display brightness (using the brightness function) and stores the value in a variable named brightness:

let brightness = led.brightness()

Math functions

The math library includes math related functions. In the Touch Develop editor, click math on the Code Keyboard to see the math functions. For example, the mod function returns the modulus (division of one number by another number):

number1 = math.mod(4, 3)

Convert a number to a string

The to string function converts a Number into a String. The following code converts number1 to a string and stores the string in the str variable:

let str = number1.toString()

Bit-level manipulation

The bits library includes functions for bit-level manipulation of integers. In the Touch Develop editor, click bits on the Code Keyboard to see these functions.

Lessons

counter, love meter, flipping bird, catch the egg game

See also

math library, var, bits library, Boolean, show number