Posted on May 5, 2021 • Originally published at boringrails.com on May 5, 2021

Quickly explore your data with `uniq` and `tally`

A common question you may want to answer on user-input data is: what values have been entered and how many times is each one used?

Maybe you have a list of dropdown options and you want to investigate removing a rare-used option.

Ruby has two handy methods that I reach for often: uniq and tally.

Usage

The uniq method operates on an enumerable and compresses your data down to unique values.

Outreach::Task.all.map(&:status).uniq => ["Confirmed w/o Outreach", "Awaiting Outreach", "Responded", "No Response Expected", "Follow-up", "Awaiting Reply"]

While most developers are familiar with uniq, the tally method is one of the best kept secrets in Ruby. The tally method takes an enumerable of values and returns a hash where the keys are unique values and the values are the number of times the value appeared in the list.

Outreach::Task.all.map(&:status).tally => {"Confirmed w/o Outreach"=>106, "Awaiting Outreach"=>28, "Responded"=>48, "No Response Expected"=>10, "Follow-up"=>4, "Awaiting Reply"=>8}