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random()

Returns a random number or a random element from an array.

random() follows uniform distribution, which means that all outcomes are equally likely. When random() is used to generate numbers, all numbers in the output range are equally likely to be returned. When random() is used to select elements from an array, all elements are equally likely to be chosen.

By default, random() produces different results each time a sketch runs. The randomSeed() function can be used to generate the same sequence of numbers or choices each time a sketch runs.

The version of random() with no parameters returns a random number from 0 up to but not including 1.

The version of random() with one parameter works one of two ways. If the argument passed is a number, random() returns a random number from 0 up to but not including the number. For example, calling random(5) returns values between 0 and 5. If the argument passed is a table, random() returns a random element from that table. For example, calling random({'🦁', '🐯', '🐻'}) returns either a lion, tiger, or bear emoji.

The version of random() with two parameters returns a random number from a given range. The arguments passed set the range's lower and upper bounds. For example, calling random(-5, 10.2) returns values from -5 up to but not including 10.2.

Examples

random example 1

function setup()
  size(100, 100)

  background(200)

  -- Get random coordinates between 0 and 100.
  local x = random(0, 100)
  local y = random(0, 100)

  -- Draw a point.
  strokeWeight(5)
  point(x, y)

  describe('A black dot appears in a random position on a gray square.')
end

random example 2

function setup() 
  size(100, 100)

  background(200)
  fill(0)

  -- Create an array of emoticons.
  local emoticons = {'=)',':p','=|8^)'}

  -- Choose a random element from the array.
  local choice = random(emoticons)

  -- Style the text.
  textAlign(CENTER)
  textSize(20)

  -- Display the emoji.
  text(choice, 50, 50)

  describe('An emoticon face is displayed at random.')
end

random example 3

function setup() 
  size(100, 100)

  -- Slow the frame rate.
  frameRate(5)

  describe('A black dot moves around randomly on a gray square.')
end

function draw() 
  background(200)

  -- Get random coordinates between 0 and 100.
  local x = random(100)
  local y = random(100)

  -- Draw the point.
  strokeWeight(5)
  point(x, y)
end

random example 4

function setup() 
  size(100, 100)

  -- Slow the frame rate.
  frameRate(5)

  describe('A black dot moves around randomly in the middle of a gray square.')
end

function draw() 
  background(200)

  -- Get random coordinates between 45 and 55.
  local x = random(45, 55)
  local y = random(45, 55)

  -- Draw the point.
  strokeWeight(5)
  point(x, y)
end

random example 5

local x = 50
local y = 50

function setup() 
  size(100, 100)

  background(200)

  describe('A black dot moves around randomly leaving a trail.')
end

function draw() 
  -- Update x and y randomly.
  x = x + random(-1, 1)
  y = y + random(-1, 1)

  -- Draw the point.
  point(x, y)
end

Syntax

random([min], [max])

random(choices)

Parameters

Parameter
min Number: lower bound (inclusive).
max Number: upper bound (exclusive).
choices Table: table to choose from.

Returns

Number: random number.