Ruby: Merging variables in to a string

Question

Hello,

I'm looking for a better way to merge variables in to a string, in Ruby.

For example if the string is something like:

"The animal action the *second_animal*"

And i have variables for Animal, Action and Second Animal, what is the prefered way to put those variables in to the string?

Thanks

James

Answer 1

The idiomatic way is to write something like this:

"The #{animal} #{action} the #{second_animal}"

Answer 2

You can use sprintf-like formatting to inject values into the string. For that the string must include placeholders. Put your arguments into an array and use on of these ways: (For more info look at the documentation for Kernel::sprintf.)

fmt = 'The %s %s the %s'
res = fmt % [animal, action, other_animal]  # using %-operator
res = sprintf(fmt, animal, action, other_animal)  # call Kernel.sprintf

You can even explicitly specify the argument number and shuffle them around:

'The %3$s %2$s the %1$s' % ['cat', 'eats', 'mouse']

Answer 3

Consider an eRuby, erubis is good, or other templating system.