%

FormatâUses str as a format specification, and returns the result of applying it to arg. If the format specification contains more than one substitution, then arg must be an Array or Hash containing the values to be substituted. See Kernel::sprintf for details of the format string.

"%05d" % 123                              #=> "00123"
"%-5s: %08x" % [ "ID", self.object_id ]   #=> "ID   : 200e14d6"
"foo = %{foo}" % { :foo => 'bar' }        #=> "foo = bar"