Ruby concatenate strings and add spaces

Question

I have 4 string variables name, quest, favorite_color, speed that might be empty. I want to concatenate them all together, putting spaces between those that aren't empty.

So:

name = 'Tim'
quest = 'destroy'
favorite_color = 'red'
speed = 'fast'

becomes

'Tim destroy red fast'

and

name = 'Steve'
quest = ''
favorite_color = ''
speed = 'slow'

becomes:

'Steve slow'

(Notice: there is only 1 space between 'Steve' and 'slow')

How do I do that (preferably in 1 line)?

EDIT: should have put this earlier. Simplicity of the code (IE how simple is to to look at and understand) is more important than speed.

Answer 1

You can use inject:

[name,quest,favorite_color,speed].inject("") {|k,v| v.empty? ? k : k << " " << v }.strip

Answer 2

[name, quest, favorite_color, speed].reject(&:empty?).join(' ')

Answer 3

Try [name,quest,favorite_color,speed].join(' ').squeeze(' ')