Randomly find numbers from 1-12 without repeat [duplicate] - vb.net

Question

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Pick unique Random numbers
(1 answer)
Closed 5 years ago.
I have three variable integers, and I have the following code that randomizes their value:
Randomize()
number = Int(Rnd() * 12) + 1
AssignImagesToSquares()
number2 = Int(Rnd() * 12) + 1
AssignImagesToSquares()
number3 = Int(Rnd() * 12) + 1
AssignImagesToSquares()
And AssignImagesToSquares is a Private Sub where I use them.
However, the problem that I am facing is that numbers can be repeated. I could not figure out how to do it, but in psuedocode,
'Randomize the integer "number"
'Randomize the integer "number2" where number2 <> number
'Randomize the integer "number3" where number3 <> number2 <> number.
I thought of maybe using a loop to repeat the process until a match is found but how exactly can that be done?

Answer 1

As a simple solution you could just use a Do..Loop until the numbers do not match, for example
Randomize()
number = Int(Rnd() * 12) + 1
AssignImagesToSquares()
Do
number2 = Int(Rnd() * 12) + 1
If number2 <> number Then
AssignImagesToSquares()
Exit Do
End If
Loop
Do
number3 = Int(Rnd() * 12) + 1
If number3 <> number AndAlso number3 <> number2 Then
AssignImagesToSquares()
Exit Do
End If
Loop

Answer 2

Yes you could use loops, but alternatively given your situation you could store your values in array, and take values from this array, and as soon as you pick a value from array you remove it. Then you could use it again. Simple code provided (of course it would be better wrapped in a function):
Dim number1, number2, number3 as Integer
Dim numbers = New Integer() {1,2,3,4,5,6,7,8,9,10,11,12}
Dim indx As Integer = Int(Rnd() * numbers.Length)
number1=numbers(indx)
Console.WriteLine(number1)
System.Array.Clear(numbers, indx, 1)
indx=Int(Rnd() * numbers.Length) 'wrap in function
number2=numbers(indx) '
Console.WriteLine(number2) 'AssignImagesToSquares()
System.Array.Clear(numbers, indx, 1) '

Answer 3

MAYBE a little overkill ;) , but you can extend this for any number of numbers wanted:
Dim temp As New ConcurrentDictionary(Of Integer, Integer)
Dim count_actual As Integer = 0
Dim count_wanted As Integer = 3
Do
Dim number = Int(Rnd() * 12) + 1 'or whatever random function
If temp.TryAdd(number, count_actual) Then
count_actual += 1
End If
Loop While count_actual < count_wanted
Dim yourNumbers = temp.OrderBy(Function(v) v.Value).Select(Of Integer)(Function(v) v.Key).ToArray()
Now there are your wanted random different numbers in the yourNumbers array. Just use them.