Random generation question

Question

The actual art for my final is coming together but I cannot get my random generation to work. I want it so that each of the hills, thesky, the background, and the extra objects have a one in three chance of being selected when generating. Here's the code.

to gen-hills
  if random 3 = 0 [
    grassy-hills
  ]
  if random 3 = 1 [
    sandy-hills
  ]
  if random 3 = 2 [
    snowy-hills
  ]
end

to gen-sky
  if random 3 = 0 [
    morning
  ]
  if random 3 = 1 [
    sunset
  ]
  if random 3 = 2 [
    nighttime
  ]
end

to gen-back
  if random 3 = 0 [
    town
  ]
  if random 3 = 1 [
    forest
  ]
  if random 3 = 2 [
    ocean
  ]
end

to gen-extras
  if random 3 = 0 [
    birds
  ]
  if random 3 = 1 [
    clouds
  ]
  if random 3 = 2 [
    planes
  ]
end

My logic is that each option will have a one in three chance in being created which is why I have them reach doing "random 3." But sometimes when I run the code I get multiple things overlapping or not being drawn correctly or nothing being drawn at all. What steps should I take to remedy this problem?

Answer 1

You should declare a variable before your if statements like this:

let check random 3

and then your if statements should look like this:

if check = 0 [ option1 ]
if check = 1 [ option2 ]
if check = 2 [ option3 ]

Comments

Thank you. This works

Answer 2

using ifelse instead of if will work!

Answer 3

I try to change your code. They are the same. I use ifelse statements and take caution on using random.

  to gen-hills
  ifelse (random 3 )= 0 [
    grassy-hills
  ] [
    ifelse (random 3) = 1 [
      sandy-hills
    ] [
      if (random 3) = 2 [
        snowy-hills
      ]
    ]
  end

to gen-sky
  ifelse (random 3) = 0 [
    morning
  ] [ 
    ifelse (random 3) = 1 [
      sunset
    ] [
      if (random 3) = 2 [
        nighttime
      ]
    ]
end