Android Question random number except of one number...

[ilan]

can i get a random number except of a specific number?

like dim rnd1 as int = rnd(1,10) but nr 2 & 5 not allowed..

is that possible?

 

[JordiCP]

Why does my answer not work?

 

[sorex]

because you can only supply one forbidden number to it?

 

[JordiCP]

i want the levels load randomly again and agian but not same level twice after he was loaded.
but he can be again loaded if another level was before

like 2,4,5,3,2,4,2,6,7,5,6,7,....

That's what I understand ilan is asking for

 

[Gunther]

ok, that is a little different than since in #1 you asked to avoid 2 numbers...

Dim intNewNumber As Int = Rnd(1, 10), intOldNumber as Int = intNewNumber
'
Do Until intNewNumber <> intOldNumber

   intNewNumber = Rnd(1, 10)

Loop
intOldNumber = intNewNumber

 

[ilan]

Why does my answer not work?

hi jordiCp@

your code:

Sub randomfunction(maxint As Int,forbiddennr As Int) As Int
   Dim rnd1=Rnd(1,maxint-1)
   if rnd1>=forbiddennr then
      rnd1=rnd1+1
   end if
End Sub

the problem is if the forbidennumber was 10 (last level) and rnd1 was again 10 then the app will look for a new level that does not exist (level 11)

actually you are correct, it may work

 

[JordiCP]

If forbiddennumber was 10, the function would only look between 1 and 10-1, so it would never happen

I want my beer!!!!

 

[ilan]

If forbiddennumber was 10, the function would only look between 1 and 10-1, so it would never happen

I want my beer!!!!

you deserve it:

lot of thanx to all others ...

 

[sorex]

but...

that solution doesn't check for the 2 your requested

if you want to get rid of 4 & 5 this will fail on 4 as it becomes 5

 

[ilan]

but...

that solution doesn't check for the 2 your requested

your are correct, at least we solved 50%

 

[derez]

It is an old question which was discussed here https://www.b4x.com/android/forum/threads/rnd-problem-question.45544/

 

[DonManfred]

thnax guys, can it be done without any loops?

Write a new RND library which can get an additional parameter for results to filter.

Elsewhere: NO

 

[LucaMs]

can i get a random number except of a specific number?

like dim rnd1 as int = rnd(1,10) but nr 2 & 5 not allowed..

thnax guys, can it be done without any loops?

Dim Allowed As List
Allowed.Initialize2(Array As Int(1,3,4,6,7,8,9,10))
Dim OneNumber As Int = Allowed.Get(Rnd(1, Allowed.Size))

 

[ilan]

Dim Allowed As List
Allowed.Initialize2(Array As Int(1,3,4,6,7,8,9,10))
Dim OneNumber As Int = Allowed.Get(Rnd(1, Allowed.Size))

have also tried it with a list,... but your code is much more prettier...

 

[sorex]

simular as doing it without a list but with just an array, it limits flexibility unless you clear and refill the list again.

 

[LucaMs]

The arrays are dead; they were replaced by Lists, Maps, Hashtables.

 

[sorex]

nah, arrays still have benefits for some tasks.

 

[LucaMs]

nah, arrays still have benefits for some tasks.

Whatever you can do with arrays, you can do it with Lists or Maps (in B4X) but not vice versa.

 

[Troberg]

Even neater solution:

Put all the levels in a list in a random order. Then, take a random one from the first 8 (assuming 10 levels and 2 barred). Then, simply put the used one at the end of the list. The next time, just re-use the list.

 

[Troberg]

Arrays can be de

Whatever you can do with arrays, you can do it with Lists or Maps (in B4X) but not vice versa.

Arrays can be declared as being of a type. You can't do that with a map or list (something which would be very nice to be able to do).

 

[LucaMs]

Arrays can be de


Arrays can be declared as being of a type. You can't do that with a map or list (something which would be very nice to be able to do).

In a Map you can have many objects of different types, you can not with arrays.

Also, in other languages, like VB.Net, you can have:
Dim MyList As List Of(...)