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Ruby ActiveRecord Basics Query Interface Finding Scopes 2

Philip Benton
Philip Benton
1,378 Points
Posted by Philip Benton
Philip Benton
1,378 Points

What is the difference between having the : at the beginning or end of a Ruby symbol?

I'm just working through some of the Active Record videos and keep getting confused between the : being at the beginning or end of a Ruby symbol.

Can someone enlighten me as to the difference and use cases?

2 Answers

Andrew Olson
Andrew Olson
4,028 Points

Hi Phillip!

Using the : at the end of a symbol is usually reserved for specifying a hash key.

Something like:

{
  username: 'jane',
  number_of_logins: 2,
  favorite_color: 'blue'
}

Using the : at the beginning of the symbol is usually used for assigning a value.

Something like:

favorite_color = :blue

You can also combine the two:

{
  favorite_color: :blue
}

Hope this helps.

Philip Benton
Philip Benton
1,378 Points
Philip Benton
Philip Benton
1,378 Points

Hey Andrew, that's a great help thanks.

Are both cases still classed as symbols?

Andrew Olson
Andrew Olson
4,028 Points

Exactly, they're both just symbols.

Try it out with irb:

irb(main):001:0> hash = { favorite_color: :blue }
=> {:favorite_color=>:blue}
irb(main):002:0> hash.keys.first.class
=> Symbol
irb(main):003:0> hash.values.first.class
=> Symbol