Problem when trying to split an array of randomly ordered numbers into two equal parts using Godot/Gdscript

Question

I am currently creating a game in Godot 3.2.3, and in this game I need to create an array that contains numbers from 1 to array.size() (example:[0,1,2,...,30]) and that such numbers are in random order, to be further divided into 2 sub arrays.

The code below demonstrates the process:

func createImageSets(var size):
var arr = Array()
var n = 1
while (n <= size):
    arr.append(n)
    n = n + 1
arr.shuffle()
var half = size/2
study_set = arr.slice(0,half-1)
other_set = arr.slice(half, size-1)
print(study_set)
print(other_set)

Obs: study_set and other_set are variable from script.

When I try to print the sub arrays, I get this result:

[11, 16, 5, 25, 12, 2, 27, 17, 23, 21, 14, 7, 19, 13, 9]
[6, 10, 26, 24, 29, 3, 1, 8, 15, 18, 4, 22, 28, 20, 30]

I realized that every time I run this script, the order of the numbers generated in shuffle() It is the same, as if the method did not create a new instance to generate the shuffle between one execution and another. No matter how many times you run, the result is always these same 2 arrays.

I would like each execution to provide me with different sets of numbers. Could someone help me with this?

Answer 1

You have to call randomize() before the arr.shuffle().

extends Node2D

var a = [1,2,3,4,5,6,7,8,9]

func _ready():
    randomize()
    a.shuffle()
    for i in range(9):
        print(a[i])

Link for you to test: Here.

Source: QA - godotengine.org