Rails check if an array exists

Question

Sorry for my probably noobish question; I recently started developing with Rails. I checked through the API, documentation, and did a bunch of searches but could not find what I was look for.

Is there a method to check to see if a specific array exists?

For example,

    array = []
    array = [2,3,4]
    if array.exists?
      puts "array exists!"
    else
      puts "No such thing!"
    end

Thanks

What do you mean by exists? Has content?

Kristján
– Kristján

2015-06-04 14:19:10 +00:00
Commented Jun 4, 2015 at 14:19 — Kristján
– Kristján, Commented Jun 4, 2015 at 14:19
No, More like is declared.

WhyEnBe
– WhyEnBe

2015-06-04 14:24:45 +00:00
Commented Jun 4, 2015 at 14:24 — WhyEnBe
– WhyEnBe, Commented Jun 4, 2015 at 14:24

Max Williams · Accepted Answer · 2015-06-04 14:19:35Z

5

like so:

if defined?(array)

instance variables (eg @array) default to nil, so you can just test them with

if @array

answered Jun 4, 2015 at 14:19

Max Williams

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1 Comment

WhyEnBe Over a year ago

Thanks so much for your lightning fast answer!

rkamun1 · Accepted Answer · 2015-06-04 14:21:03Z

2

Note: By defining your array with array = [], your array will always exist. But if you want to check if array is an Array, you can say array.is_a?(Array)

answered Jun 4, 2015 at 14:21

rkamun1

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Comments

Akshay Borade · Accepted Answer · 2015-06-04 14:21:42Z

0

Try this

a = [1,2,3]

a.any?
=> true

a.clear

a.any?
=> false

answered Jun 4, 2015 at 14:21

Akshay Borade

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Comments

Jorgesys · Accepted Answer · 2015-06-04 14:29:48Z

0

Hi fellas i´m newbie at Ruby on Rails but this is the most simple way:

if (defined?(array))
   puts "array exists!"
else
   puts "No such thing!"
end

answered Jun 4, 2015 at 14:29

Jorgesys

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1 Comment

WhyEnBe Over a year ago

Thanks for the precise example.

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