I have kind of a general question, and please forgive me if it is inappropriate. I use BASIC extensively for simulation of ecological systems, mainly because I learned it when I was 10 and never bothered to switch. Recently I was exposed to OOP and its possible uses in simulating population ecology, and now want to "upgrade" my programming abilities by learning a new language. I have, however, relatively little time to try out many languages (my day job interferes), and so thought I might save time by describing to the "experts" exactly what I want to do, and whether they think Ruby is going to accomplish what I want. Basically, I simulate the population ecology of wildlife disease. Whether an animal gets a disease or not, and then the progression of the disease once infected, is a function of a number of attributes of that individual. OOP seems perfect for this task, as each individual would be an object, with "attributes" (sex, age, immune status, presence or absence of disease etc.) and "behaviours" (give birth, die, become infected, migrate etc.). From my preliminary reading of Ruby this would seem pretty straight forward. The problem I forsee is that the objects would have to be stored in a "vector" or "array" (I think the C++ terminology would be containers?). Each time step (e.g., one year), I would iterate through the vector "killing" some animals (thus the vector or array of objects would contract), and then have the survivors "give birth" (thus the vector would expand). Therefore, the framework that I store the objects would have to shrink and expand dynamically as the population changes. An alternative would be to have a really long vector or array that never has any chance of filling up, but this seems to me to be a waste of memory. I'm not looking for a "how-to-do-this" in any specific way type of answer, but rather if this dynamic array or vector is possible in Ruby. I have a friend who programs in C and is learning C++ and he is having a heck of a time figuring this out. Any advice would be greatly appreciated, Damien __________________________________________________ Do You Yahoo!? Try FREE Yahoo! Mail - the world's greatest free email! http://mail.yahoo.com/