Adding commas to a number

Question

I\'m trying to make a number like 1234567 go to be 1,234,567, but need some help. My thoughts were that I could use a split with \\d{3} and then join a , to that. T

Answer 1

i dont know if ruby has already an option to format numbers but in regex you can do this

/\G([+-]?\d+?)(?=(?:\d{3})++(?=\.\d++$|$))/g

then replace with this

\1,

sample: http://regex101.com/r/bA9cV2

Answer 2

I'd use Rails' ActiveSupport (even if I wasn't using Rails for the actual application), which also formats it properly for the current locale. If you aren't already using Rails, you'll need to install the gem:

gem install activesupport

Then, require it like this:

require "active_support/core_ext"

Then you can do:

=> ActiveSupport::NumberHelper.number_to_delimited(1234567)
=> "1,234,567"

Answer 3

More precise code (handles integers only, as OP did not mention floats!):

def group_digits(n)
  n.to_s.chars
   .reverse
   .each_slice(3)
   .map(&:join)
   .join(",")
   .reverse
end