dynamically change method name inside array in ruby

Question

I have a user object which i access like this.. user.email, user.first_name

Now I want to loop through each and return a message based on the current key in loop somewhat like this.

[user.first_name, user.email, user.last_name].each do |key|
      puts "#{key} is required"
 end

The above works but loops through values instead of fields. so will do this below but how to prepend user to keys and get values inside array?

[first_name, email, last_name].each do |key|
 #inside here I want to prepend the user to the keys so that I can access like user.key 

 puts "#{user.key} is required" 
end

If this was a string we can concatenate but how to deal with this here as its a method call?

Are you asking how to use key as a method call on user?

jvillian
– jvillian

2017-03-29 19:29:39 +00:00
Commented Mar 29, 2017 at 19:29 — jvillian
– jvillian, Commented Mar 29, 2017 at 19:29
@jvillian yes...

Abhilash
– Abhilash

2017-03-29 19:30:06 +00:00
Commented Mar 29, 2017 at 19:30 — Abhilash
– Abhilash, Commented Mar 29, 2017 at 19:30

tadman · Accepted Answer · 2017-03-29 19:53:41Z

2

With ActiveRecord you can access properties via the [] method:

[ :first_name, :email, :last_name ].each do |key|
  unless (user[key])
    puts "#{key} is required"
  end
end

This generally a lot safer than the send approach because it's not calling arbitrary methods.

answered Mar 29, 2017 at 19:53

tadman

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jvillian · Accepted Answer · 2017-03-29 19:30:34Z

1

You can simply do:

user.send(key)

answered Mar 29, 2017 at 19:30

jvillian

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Comments

Ruslan · Accepted Answer · 2017-03-29 19:30:24Z

-1

[first_name, email, last_name].each do |key|
 puts user.send(key)
end

answered Mar 29, 2017 at 19:30

Ruslan

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