Well, not really but it has made my job easier and I think it could do the same for you.
I’m relatively new to Ruby and in my past life my bread and butter language was PHP. When I was told that our stacks were going to be ripped down and replaced with Ruby on Rails I had mixed emotions. In one hand I was really excited to be working with Ruby on Rails. A new cool language to sink my teeth into. On the other hand I was going to be working with Ruby on Rails! I thought, OK maybe this wont be so bad. I can use what I know about PHP and apply it to Ruby on Rails. So I hit the books and tutorials and anything I could get my hands on. I quickly learned that Ruby on Rails and Ruby had a lot of built in magic and PHP had none of that. It took me a long time to get my head around it. A colleague told me to just “believe in the magic”. Well, now I believe and I would like to share some of that “magic” with you.
One of the events that really help me believe was a suggestion from another colleague. He told me about this blog called “Ruby Tapas” by Avdi Grimm. You have to check it out! I can’t say enough good things about it but maybe I’ll save that for another blog post. Everyday I would go through his posts while commuting to work. I would sit on the train with my headphones on staring at my phone and continually saying out loud “ah that’s cool!”. My fellow commuters started to sit a little further away from me each day.
One of those “ah that’s cool!” moments came after I saw Avdi’s post about this strange enumerator called partition.
What is partition and what does it do?
Returns two arrays, the first containing the elements of enum for which the block evaluates to true, the second containing the rest.”
In simpler terms it splits a collection into two subsets based on some criteria.
A few days later after stumbling on this gem I was tasked with building a tool for our Web Edit Team. This team will sometimes free up content on our sites and they needed a quick and easy way to find out which pieces of content are currently free. The bit of logic we have built into our code to determine if a piece of content is free doesn’t use a status attribute but instead uses start and end dates to determine if something is currently free. I thought this would be so much easier if we just had a status attribute and I could easily just query everything that had a status of active. I thought, I could make a schema change and add the new attribute and run a daily job to check and alter the status but that just seemed like crazy town. Then I thought about the Ruby “magic” and the post I saw a few days earlier about partition. Everything just fell into place. I didn’t need to make a crazy schema change it was just for a view after all. Partition was exactly what I needed.
So I built a helper that would take an array of hashes and easily split the array into to two arrays. An active array and an inactive array.
The next part was even easier. I just needed to create a view that called the helper and returned the instance variables @active and @inactive. Once I checked for the presence of the instance variables all that was left to do was iterate over the arrays.
So the next time you find yourself needing to split a collection into two subsets based on some criteria just remember this story and the “magic” of partition.