How to round a number to the nearest 9 in Ruby -

how round number nearest 9 in ruby?

my desired effect if number 22.22 round down 19. if number 26.34 round 29

any ideas?

thanks

unfortunately, round() methods float don't have syntactic sugar rounding other nearest integer. 1 can build one's own methods—

this method assumes numbers positive. readability, advise wrap convoluted numerical calculation method name refers it's doing.

def round_to_nearest_9(num)   ((num + 1) / 10).round * 10 - 1 end 

if don't want assume input number positive:

def round_to_nearest_9(num)   if num < 0     return ((num - 1) / 10).round * 10 + 1   else     return ((num + 1) / 10).round * 10 - 1   end end