+36 votes

I dont remember what language it was but you could do random(1,10) or something like that and it would pick a number between 1 to 10, is there a way to do something like this in gdscript?

in Engine by (483 points)

8 Answers

+20 votes

yes. rand_range(float from, float to)

use randomize() before for "true" random numbers

by (423 points)

Okay thanks for the help ^^

I like this answer better because it mentions the randomize function, which without it, chooses the same "random" numbers every time.

Thanks for mentioning randomize. Is there an approach that permits to specify a seed number?

RandomNumberGenerator in Godot 3.1 allows to set any seed for each instance, so you could have independent "deterministic" generators in GDScript for different purposes within a game (randomizing different set of independent features).

+62 votes

randi()%10+1 returns an int from 1 to 10

randf()*10.0+1.0 returns a float from 1.0 to 10.999999~

rand_range(1,11) returns a float from 1.0 to 10.999999~

range(1,11)[randi()%range(1,11).size()] is a little ugly and less efficient but returns an int from 1 to 10 without you having to do the math yourself (aka the 11+1 part) because all you need to do is set the range()

by (840 points)
reshown by

Answer changed due to more info

Yay I won! Take that tiernich!

lol - defeat accepted :D

To get a random integer between 1 and 10, I find it more intuitive to floor the random float in range. More specifically:
floor(rand_range(1, 11))

randi()%11+1 is probably biased towards lowest values of 1..10

I'm trying to generate a random between 10-30 (randi()%30+10) but it's giving me a 35. Probably doing it wrong, but can't figure out how to make it right.

try (randi()%30)+10

Don't forget to call randomize

This answer has an important error. If you want to produce a real number in the interval [x,y[, in general you use:

(randf() * (y-x)) + x.

From 1 to 10, you have randf() * 9 + 1. This is because randf() can be 1 as maximum. In this case, you would obtain 9 + 1 = 10. In the case proposed by this answer, randf() * 11 + 1, if by chance randf() turns out to be greater than 0.8 you get something greater than 10. So, there is a 20% chance of having a wrong answer.

randi()%11+1 returns an int from 1 to 11

If you someone needs a random int between 1 and 10, use:
randi()%10+1

Please note that randi()%11+1 return a number between 1 and 11 not 10
because randi()%11 can be 10 and adding 1 to it will make it 11. the same thing for randf()

yes indeed, obviously and i don't know how we could go so wrong

Corrected the inaccuracies. The random floats won't return a 1.0, but at most .999999~.

The last method using arrays I left, but would recommend int(rand_range(1,11)) as an alternative.

+7 votes

As of Godot 3:

randi() % 20 returns an int from 0 to 19

randi() % 20 + 1 returns an int from 1 to 20

randf() returns a float from 0 to 1

Unfortunately, the older style no longer seems to work.

by (54 points)
edited by

Just a correction on the third line.

randi() % 20 + 1 won't return an int from 0 to 20.

It'll be an int from 1 to 20. Still very helpful, thanks.

+4 votes

The following code returns a random number, but it is the same number each time the script is executed:

var random_value = rand_range(1,10)

The following code gives you different random numbers each time the script is executed:

var random_generator = RandomNumberGenerator.new()
random_generator.randomize()
var random_value = random_generator.randf_range(1,10)

https://docs.godotengine.org/en/stable/classes/class_randomnumbergenerator.html

or simply:

randomize()
var random_value = rand_range(1,10)
by (207 points)
edited by

You don't need to call randomize() every time you pick a random number. Just call it once after starting the project.

Oh. You are right. We don't need to call randomize() in every script.

+1 vote

I needed a rand_range(a, b) but with integers, also to work with negative numbers. I came up with this function.

func randi_range(from, to):
    if from > to:
        var old_from = from
        from = to
        to = old_from
    return int(floor(rand_range(from , to + 1)))
by (16 points)
0 votes

You can use key words like randomize for randomizing numbers from 0 to 2^32, randrange for randomizing an specific range of numbers, for example randrange(2, 20) will return 2,3,4,5,6...19 or 20. There also at options like randi () or randf but I think those are the more important. I’ll link rand_range since is the specific one in your case: https://docs.godotengine.org/es/stable/getting_started/scripting/c_sharp/c_sharp_differences.html?highlight=Rand_range#random-functions

by (14 points)
0 votes

var name = 0

func ready():
rng.randomize()
name = rng.randi
range(1, 10)

The random number will be between 1 and 10.

by (254 points)
0 votes

Yea, the best way i found out how is this way:

    var RNG = RandomNumberGenerator.new()

func _ready():
    RNG.randomize
    var rannum = RNG.randf_range([number], [number])

So that's the code. hopefully it helps!

by (21 points)
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