Question

I want to look at every n-th elements in an array. In C++, I’d do this:

for(int x = 0; x<cx; x+=n){
    value_i_care_about = array[x];
    //do something with the value I care about.  
}

I want to do the same in Ruby, but can’t find a way to “step”. A while loop could do the job, but I find it distasteful using it for a known size, and expect there to be a better (more Ruby) way of doing this.

Answer 1

Ranges have a step method which you can use to skip through the indexes:

(0..array.length - 1).step(2).each do |index|
  value_you_care_about = array[index]
end

Or if you are comfortable using ... with ranges the following is a bit more concise:

(0...array.length).step(2).each do |index|
  value_you_care_about = array[index]
end