Calling an array in an each loop find_by_email

Question

I'm trying to cycle through an array in console and use find_by_email to locate the User:

a = [ "[email protected]",  "[email protected]"]
a.each do |email|
 u = User.find_by_email("#{a}")
 u.delete
end

But I'm getting an error:

NameError: undefined local variable or method `email' for main:Object

Here, what I get based on the answer:

1.9.3p194 :035 > a = [ "[email protected]",  "[email protected]"]
 => ["[email protected]", "[email protected]"] 
1.9.3p194 :036 > a.each do |email|
1.9.3p194 :037 >     u = User.find_by_email(email)
1.9.3p194 :038?>   u.destroy
1.9.3p194 :039?>   end
  User Load (0.7ms)  SELECT "users".* FROM "users" WHERE "users"."email" = '[email protected]' ORDER BY users.created_at DESC LIMIT 1

NoMethodError: undefined method `destroy' for nil:NilClass

Niels B. · Accepted Answer · 2013-07-07 16:11:52Z

2

First, don't use #{a}. It refers to the array, use the email variable passed into the loop, which refers to the email of that iteration.

u = User.find_by_email(email)

The reason you are getting the error, is because you are missing do.

a.each do |email|
  u = User.find_by_email(email)
  u.destroy
end

You can optimize the query by writing.

User.where(email: a).destroy_all

edited Jul 7, 2013 at 16:11

answered Jul 7, 2013 at 15:44

Niels B.

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9 Comments

Brian McDonough Over a year ago

Hi Niels, that gives me: NoMethodError: undefined method `delete' for nil:NilClass. I've pasted the logs in my question.

Niels B. Over a year ago

Yes, the method you are looking for is called destroy.

Brian McDonough Over a year ago

a = [ "[email protected]", "[email protected]"] a.each do |email| u = User.find_by_email(email) u.destroy end NoMethodError: undefined method `destroy' for nil:NilClass

Niels B. Over a year ago

In that case, you don't have any users with those e-mail addresses.

Niels B. Over a year ago

Try User.where(email: a).count

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