Is it a ruby idiom for nil is true?

Question

Hi I want to have a condition, which when it is nil, it true, or it call check method and return true/false. For example:

(apple.nil? || apple.sweet?) && (pear.nil? || pear.sweet?)

It checks if all the fruits are sweet(only apple&pear here). Is there any ruby idiom to simplify this code?

Cheers

Amadan · Accepted Answer · 2019-11-08 05:00:47Z

6

if all the fruits are sweet

[apple, pear].compact.all?(&:sweet?)

compact gets rid of the nil elements, then all?(&:sweet?) checks if all remaining ones are sweet.

edited Nov 8, 2019 at 5:00

answered Nov 8, 2019 at 4:47

Amadan

200k23 gold badges252 silver badges321 bronze badges

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

1 Comment

Stefan Over a year ago

Even works for the edge case of an empty array: all? returns true in that case.

Stefan · Accepted Answer · 2019-11-08 08:06:27Z

An alternative to the solution given by Amadan:

fruits.all? { |f| f.nil? || f.sweet? }

While the idea of using compact, as Amadan correctly suggested, is nice and concise, it will likely create a temporary array of the non-nil elements, while just using all? does not need such an array, and iteration stops as soon an element has been encountered which does not fulfil the condition.

Of course if you only have exactly two fruits in your code, which are mentioned expcitly, I would consider your code better to understand than doing a

[apple,pear].all? {...}

Collectives™ on Stack Overflow

Is it a ruby idiom for nil is true?

2 Answers 2

1 Comment

Comments

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Related