Count truthy objects in an array

Question

I'd like to count truthy objects in an array. Since I can pass a block to count, the most idiomatic way I found was this:

[1, nil, 'foo', false, true].count { |i| i }
#=> 3

But I was wondering if there was a better way, especially using the syntax count(&:something), because passing a full block here looks like overkill to me.

AFAIK, there is no truthy? method in Ruby, so I couldn't find how to achieve this.

Just out of curiosity, one might calculate an amount of falseys [1, nil, 'foo', false, true].count(&:!) and subtract it from original array’s size :) — Aleksei Matiushkin
– Aleksei Matiushkin, Commented Oct 10, 2016 at 14:04

Andrey Deineko · Accepted Answer · 2016-10-10 14:04:05Z

15

With Ruby >= 2.2 you can use Object#itself:

[1, nil, 'foo', false, true].count(&:itself)
#=> 3

edited Oct 10, 2016 at 14:04

answered Oct 10, 2016 at 13:57

Andrey Deineko

52.5k11 gold badges119 silver badges151 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

lcguida Over a year ago

Ruby 2.2.0 does that too... ruby-doc.org/core-2.2.0/Object.html#method-i-itself

arghtype · Accepted Answer · 2017-02-03 15:08:09Z

-1

Try this:

[1, nil, 'foo', false, true].count(true)

edited Feb 3, 2017 at 15:08

arghtype

4,54211 gold badges51 silver badges62 bronze badges

answered Feb 2, 2017 at 13:53

Alexander Manzyuk

5944 silver badges5 bronze badges

1 Comment

Mat Over a year ago

This only counts true objects. The goal was to count all truthy objects (ie. 1 and 'foo' should also be counted.)

Collectives™ on Stack Overflow

Count truthy objects in an array

2 Answers 2

1 Comment

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related