Substituting variables into an Existing String

From last recipe,we know a way of substituting variables into string. Here, there are some ways again.

1. Printf-style string format
var = 'My name is %s.'
var % 'Allen'
#=> "My name is Allen."
'To 2 decimal places: %.2f' % Math:PI
#=> "To 2 decimal places: 3.14"
'Zero-padded: %.5d' % Math:PI
#=> "Zero-padded: 00003"

2.Use ERB
require 'erb'

template = ERB.new %q{It is <%= var%>!}
var = "here"
# When var is binded to template,just like following
puts template.result(binding)
#=> print "It is here"