CODEWITHSUNDEEP
rubyactiverecord
singularity
singularity

Reputation: 593

Method as argument for each instance in ActiveRecord `where`

Can .where in active record take a method as an argument?

def not_foo?
  name != "foo"
end

The below code does not work, but you'll see what I mean:

array.where(|element| element.not_foo?).count

Upvotes: 1

Views: 75

Answers (3)

mhaseeb
mhaseeb

Reputation: 1779

The pass around methods as arguments, that is functional paradigm. In Ruby that is achieved by closures.

Closures can be implemented in Ruby through blocks, lambdas, procs.

Upvotes: 2

Shiva
Shiva

Reputation: 12514

Can .where in active record take a method as an argument?

Ans: No, it cannot. may be you want to do this

array.where.not(name: 'foo').count

Upvotes: 3

Leo Brito
Leo Brito

Reputation: 2051

You're mixing several different concepts here.

You can't "pass a method as an argument" in Ruby as you would in C or other languages. You can pass a block as an argument, which is very different.

In your example, element.not_foo? would be evaluated first. You are passing the result of that evaluation to where. There are, however, some problems in your code which would prevent it from even running:

  • The definition of not_foo? receives an argument (def nor_foo?(v)) but you passed none, which would raise an ArgumentError: wrong number of arguments (0 for 1) exception.

  • You are using block argument syntax (|element|) incorrectly. In any case, ActiveRecord's where doesn't accept a block.

Upvotes: 1

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