One thing to consider is that the Enumerable module does not include #size. You have to use #count (which enumerates over the items). This can be costly so you need to be careful.

If you're calling this on an ActiveRecord object then the conclusion is significantly different. length pulls the array into memory and count runs a "count query". size will use the cache if available and the count query if no cache is available.

Clearly explained. Thanks!!

Thanks Prabhakar!

Thanks!!!

Number 3 method 2. you mean to say there are 3 elements that have a value = 7

Yes Freddy, that is correct.