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How can you iterate through an array of objects and return the entire object if a certain attribute is correct?

I have the following in my rails app

array_of_objects.each { |favor| favor.completed == false }

array_of_objects.each { |favor| favor.completed }

but for some reason these two return the same result! I have tried to replace each with collect, map, keep_if as well as !favor.completed instead of favor.completed == false and none of them worked!

Any help is highly appreciated!

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5
  • What I want is to return the entire object favor if favor.completed and if !favor.completed Commented Jan 30, 2016 at 18:11
  • 1
    the each method always returns the original array. Commented Jan 30, 2016 at 18:11
  • 1
    Just to qualify @sugar's comment, when it has a block, Array#each returns its receiver. Commented Jan 30, 2016 at 19:04
  • What do you mean by, "return the entire object"? Do you mean you want to return an array of those objects from the first array for which a given attribute evaluates true? Or evaluates 'false'? Commented Jan 30, 2016 at 19:11
  • yes that's what I meant. I don't want to have the attribute returned Commented Jan 30, 2016 at 21:05

4 Answers 4

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78 
array_of_objects.select { |favor| favor.completed == false }

Will return all the objects that's completed is false.

You can also use find_all instead of select.

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5 Comments

Are there any non-destructive methods similar to select?
Didn't understand non-destructive, sorry.
select changes the original array, I was just wondering if there's a similar specialised method that keeps the original array intact?
No select doesn't change self. select! does.
Oh yes, I see now. Got confused now.
15

For first case,

array_of_objects.reject(&:completed)

For second case,

array_of_objects.select(&:completed)
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4 Comments

Nicely, done, assuming we both understand the question correctly. btw, I see the wand is no more.
@CarySwoveland Thanks for the kind words.
what does the :& mean?
@liyicky Please refer stackoverflow.com/questions/9429819/…
3

You need to use Enumerable#find_all to get the all matched objects.

array_of_objects.find_all { |favor| favor.completed == false }
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2 Comments

both find and 'find_all'` are returning nil for me! :( very annoying
this is the array of objects I'm calling them on [#<RequestedFavor id: 8, title: "Moving day", description: "Help me move to my new flat please!", user_id: 1, completed: false, created_at: "2016-01-30 18:19:33", updated_at: "2016-01-30 18:19:33", type: "RequestedFavor">, #<OfferedFavor id: 9, title: "Got two hours free", description: "I can spare two hours on Friday", user_id: 1, completed: false, created_at: "2016-01-30 18:19:52", updated_at: "2016-01-30 18:19:52", type: "OfferedFavor">]
0

For newer versions of ruby, you can use filter method

array_of_objects.filter { |favor| favor.completed == false }

Reference: https://apidock.com/ruby/Array/filter

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1 Comment

"Newest" means Ruby from 1.8.6_287 ?? (by your reference)

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