How would i go about picking a random number?

Question

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?

Comments

I think that language was Python.

Answer 1

yes. rand_range(float from, float to)

use randomize() before for "true" random numbers

Comments

Okay thanks for the help ^^

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

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

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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).

Answer 2

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()

Comments

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.

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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

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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()

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

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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.

Answer 3

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.

Comments

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.

Answer 4

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)

Comments

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

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

Answer 5

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)))

Answer 6

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

Answer 7

var name = 0

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

The random number will be between 1 and 10.

Answer 8

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!

Answer 9

rand_range(float from, float to)

use randomize() before for "true" random numbers

Answer 10

use randomize();

Answer 11

you could use the
randf_range(0,10)
if you want a float

randi_range
or if you want and int

(I think I wrote that right)

I dont think you need to use the randomise() function, please correct me if I am wrong

Comments

randf_range() , randi_range() - only works in Godot 4

Answer 12

Landed here wanting to find a basic Rand() function that can return a number between low and high. Supports OP original ask in addition to anyone looking for a custom low besides 1. This implementation supports negatives. It hits the low and high without going above or below.

var randNum = Rand(-10, 20)

func Rand(low, high):   
    return floor(rand_range(low, high + 1))

Answer 13

In Godot 4, use randf_range(from, to) and randi_range(from, to). They each take a minimum and maximum value, but one is for floats and the other for integers.