[SOLVED]Is there a function to randomly pick from list of strings?

[laznewb]

Hello,

Is there a function to pseudorandomly pick from a list of constant strings like this?

Code: Pascal  [Select][+][-]

1. var
2.   s1, s2, s3, str: string;
3. begin
4.   s1 := 'black';
5.   s2 := 'white';
6.   s3 := 'orange';
7.  
8.   str := RandomlySelect(s1, s2, s3); {psudocode}
9. end;

Thanks for any advice 

[Handoko]

Not sure, but I don't think there is such function. You can write your own RandomlySelect, it's not hard. This is my solution:

Code: Pascal  [Select][+][-]

1. function RandomlySelect(const S1, S2, S3: string): string;
2. begin
3.   case Random(3) of // <----- change the number to the count of the items
4.     0: Result := S1;
5.     1: Result := S2;
6.     2: Result := S3;
7.   end;
8. end;
9.  
10. procedure TForm1.Button1Click(Sender: TObject);
11. var
12.   s1, s2, s3, str: string;
13. begin
14.   s1 := 'black';
15.   s2 := 'white';
16.   s3 := 'orange';
17.   str := RandomlySelect(s1, s2, s3);
18.   ShowMessage(str);
19. end;

[Bart]

Either put the strings in an array of in a TStringList.
Then use random function to get a pseudorandom index.

Bart

[lucamar]

An example lifted from one of my programs, but note that you have to set your strings inside a TStringList (or any other TStrings descendant; in my case it's used with a ListBox items):

Code: Pascal  [Select][+][-]

1. {Randomly shuffle the items in List}
2. procedure Shuffle(const List: TStrings);
3. var
4.   Strings: array of String;
5.   i, Max, Take: Integer;
6. begin
7.   if Assigned(List) and (List.Count > 1) then begin
8.     SetLength(Strings, List.Count);
9.     Max := List.Count-1 ;
10.     for i := 0 to Max do begin
11.       Take := Random(List.Count);
12.       Strings[i] := List[Take];
13.       List.Delete(Take);
14.     end;
15.     Assert(List.Count = 0, 'Shuffle: List should now be empty but isn''t');
16.     List.AddStrings(Strings);
17.   end;
18. end;

[winni]

Hi!

Make it simple:

Code: Pascal  [Select][+][-]

1. function RandomlySelect: string;
2. Const colors: array[0..2] of string = ('black',  'white',  'orange' );
3. begin
4. result := colors[random(3) ]
5. end;
6.  

Done.

Winni

[Handoko]

Code: Pascal  [Select][+][-]

1. function RandomlySelect: string;
2. Const colors: array[0..2] of string = ('black',  'white',  'orange' );
3. begin
4. result := colors[random(3) ]
5. end;
6.  

Done.

Winni

I like this one. Easiest and simplest.

[lucamar]

Code: Pascal  [Select][+][-]

1. function RandomlySelect: string;
2. Const colors: array[0..2] of string = ('black',  'white',  'orange' );
3. begin
4. result := colors[random(3) ]
5. end;

Done.

Winni

I like this one. Easiest and simplest.

Yes, for a small set of constant strings it's probably the best

[laznewb]

Hi!

Make it simple:

Code: Pascal  [Select][+][-]

1. function RandomlySelect: string;
2. Const colors: array[0..2] of string = ('black',  'white',  'orange' );
3. begin
4. result := colors[random(3) ]
5. end;
6.  

Done.

Winni

Thanks winni, and everyone for your solutions!