Janus Bor wrote:

> I'm pretty new to Ruby and programming in general. Here's my problem:
> 
> I'm writing a program that will automatically download protein sequences
> from a server and write them into the corresponding file. Every single
> sequence has a unique id and I have to eliminate duplicates. However, as
> the number of sequences might exceed 50 000, I can't simply save all
> sequences in a hash (with their id as key)

How do you know that? Did you try it, as an experiment?