Choose random image script

Question

I'm creating a small movie with a set of random images that all appear in the same spot (no horizontal or vertical movement). I want each image to appear onscreen for two seconds, then be replaced by another randomly-chosen image. There are 17 images in the set. Here is the script I'm using:
on enterFrame
  channel=random(17)
  _movie.delay(2*60)
on exitFrame
  go to the Frame
end
This script works well. However, because the population is small - only 17 - what happens when I run the script is that a little too often it randomly chooses the same image once, twice, sometimes up to five times in a row, which gives the effect that the movie is either stuck or not working properly. I would like to find out how to modify the script so that on exitFrame it chooses randomly any of the other 16 images but not the current image. At first I thought if the script read random(16) or random(17-1) that might work, but it doesn't.
Any thoughts would be welcome.
Dallas

Answer 1

Hi Sean,
This randomizing project of mine is becoming more complex than I first realized and I now have another question that I hope you might be able to help me with.
The project breaks down into class, category, group and member. There are 9 classes (and perhaps a possibility in the future that further classes could be added). The structure and naming convention within each class is identical down to the member level. For example, Cat. 1 of Class 2 and Cat 1 of Class 7 both have the same names. Group 3 of Cat. 1 of Class 2 and Group 3 of Cat 1 of Class 6 both have the same names. However, the members of these groups do not have the same names.
In each class there are 4 categories, each with a different name. Each category contains a number of groups (each group has a different name). Each group contains a number of members. Each member in categories 1 and 2 is a bitmap image. The total number of bitmap members in the project is 21.
To give a fictionalized example (this project is not about clothing, but I'm using it as an example):
Class 1 = shirts
Class 2 = hats
Class 3 = pants
Class 4 = socks
Class 5 = shoes
etc.
Category 1 = British
Category 2 = Japanese
Category 3 = Turkish
Category 4 = Brazilian
Group 1 = Cotton
Group 2 = Synthetic
Group 3 = Speed
Group 4 = Sound
and so forth.
In Class 1 (shirts) there are British, Japanese, Turkish and Brazilian shirts and these could be made of either cotton or synthetic. In addition, there are a variety of speeds and sounds from which to choose when displaying the shirts.
In my project:
Cat. 1 has 7 groups and each group varies in the number of members with either 7, 14 or 21 (but no other alternative to these numbers).
Cat. 2 has 13 groups and each group has 7 members.
Cat. 3 does not randomize images but lets me choose any one of 12 different speeds for randomization in half-second increments.
Cat. 4 does not randomize images but lets me choose any one of 6 different sounds. Whenever the randomized image changes, this triggers the sound. The sound is not randomized but is consistent once the choice for what KIND of sound has been made. In short: tick, tick,tick, or tock, tock, tock but not tick, tock. It is possible that in the future more sounds could be added.
Navigation should allow me to start with any of the four categories. For randomization to work, I must choose within either Cat. 1 or Cat. 2 (but not both) and I must make a choice of some sort within Cat. 3 (speed of randomization) while Cat. 4 is entirely optional (sound on or off, but not required to be on and, if it's to be on then choice for which kind of sound).
There are also an additional two buttons for sound on or off than run the length of the score within any class, meaning that while randomization is occuring anywhere within a class, I can choose to turn the sound on if it's currently off or off if it's currently on. Turning it on while randomization is taking place will also probably require a choice of which kind of sound (meaning a floating window I suppose) so as not to exit the frame where randomization is taking place.
Now for my question: should I create one massive behaviour script for all classes that includes a series of nested if/else statements for each category, group and member, or should I create 4 large behavior scripts, one for each category with if/else instructions for its groups and members, or should I script at the group level, which will result in 180 separate behaviour scripts for image randomization plus additional scripts for speed and sound?
Further, I understand how to apply at the group level the script you gave me earlier (and it works beautifully), but if you think it would be more efficient now to work at the category or class level, I'm not sure how to script the if/else statements. I'm assuming that in whichever of these solutions turns out to be best, it is applied to a single sprite which will serve to display the randomly-chosen image. Bear in mind that the script you gave me randomizes the image change every two seconds. Now I'm looking to have a choice of it changing within a range of once every half-second to once every 5 seconds (e.g. 0.5 sceonds, 1 second, 1.5 seconds, 2 seconds, etc.).
An ancillary question: could this be done a different way? A friend suggested using subroutines but wasn't able to tell me how to do this because he doesn't know anything about Lingo. I was wondering whether the if/then syntax structure is Lingo's way of doing subroutines.
Your thoughts would be most welcome. If you think you can't help me with this, do you have any suggestions as to where I might turn for help (apart from the nuthouse at this point)?
Cheers,
Dallas