Ruby: How to get the first character of a string

Question

How can I get the first character in a string using Ruby?

Ultimately what I'm doing is taking someone's last name and just creating an initial out of it.

So if the string was "Smith" I just want "S".

Answer 1

>> s = 'Smith'                                                          
=> "Smith"                                                              
>> s[0]                                                                 
=> "S"                                                        

Answer 2

If you use a recent version of Ruby (1.9.0 or later), the following should work:

'Smith'[0] # => 'S'

If you use either 1.9.0+ or 1.8.7, the following should work:

'Smith'.chars.first # => 'S'

If you use a version older than 1.8.7, this should work:

'Smith'.split(//).first # => 'S'

Note that 'Smith'[0,1] does not work on 1.8, it will not give you the first character, it will only give you the first byte.

Answer 3

The regex /^([a-zA-Z])/ will return the first letter.

Answer 4

You can use Ruby's open classes to make your code much more readable. For instance, this:

class String
  def initial
    self[0,1]
  end
end

will allow you to use the initial method on any string. So if you have the following variables:

last_name = "Smith"
first_name = "John"

Then you can get the initials very cleanly and readably:

puts first_name.initial   # prints J
puts last_name.initial    # prints S

The other method mentioned here doesn't work on Ruby 1.8:

puts 'Smith'[0]           # prints 83

Of course, if you're not doing it on a regular basis, then defining the method might be overkill, and you could just do it directly:

puts last_name[0,1] 

Answer 5

Because of an annoying design choice in Ruby before 1.9 — some_string[0] returns the character code of the first character — the most portable way to write this is some_string[0,1], which tells it to get a substring at index 0 that's 1 character long.

Answer 6

"Smith"[0..0]

works in both ruby 1.8 and ruby 1.9.

Answer 7

In MRI 1.8.7 or greater:

'foobarbaz'.each_char.first