CODEWITHSUNDEEP
ruby
user114385
user114385

Reputation: 382

How does nil? work in ruby?

How come ().nil? is true in Ruby?

Upvotes: 4

Views: 264

Answers (2)

Robert Brown
Robert Brown

Reputation: 11026

Playing in irb...

a = ()
a.class # => NilClass
a.nil? # => true

Upvotes: 2

Peter
Peter

Reputation: 132417

Simple answer: () is an empty expression that evaluates to nil.

More detailed: all expressions have a result in Ruby, returning nil if there's nothing better to return. () doesn't cause any action by itself, so an expression that is merely () has nothing in particular to return. Thus the result of the expression is set to nil, and so ().nil? evaluates an empty expression, decides there's nothing much to return so returns nil. This is indeed equal to nil, so nil? says true.

Upvotes: 9

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