How to format a number 1000 as “1 000”

Question

I need a way to format numbers. I stored some numbers in my DB table, e.g. 12500, and would like to print them in this format 12 500 (so there is a

Answer 1

Another way:

12500.to_s.reverse().split(//).inject() {|x,i| (x.gsub(/ /,"").length % 3 == 0 ) ? x + " " + i : x + i}.reverse()

You can always Open the Fixnum class and add this for convenience:

module FormatNums
  def spaceify
    self.to_s.reverse().split(//).inject() {|x,i| (x.gsub(/ /,"").length % 3 == 0 ) ? x + " " + i : x + i}.reverse()
  end
end

class Fixnum
  include FormatNums
end

12500.spaceify # => "12 500"

Answer 2

This is old but the fastest and most elegant way I could find to do this is:

def r_delim(s, e)                                                               
  (a = e%1000) > 0 ? r_delim(s, e/1000) : return; s << a                        
end

r_delim([], 1234567).join(',')

I'll try and add benchmarks at some point.

Answer 3

All but one of the answers use n.to_s. @MrMorphe's does not, but he creates an array to be joined. Here's a way that uses neither Fixnum#to_s nor Array#join.

def separate(n,c=' ')
  m = n
  str = ''
  loop do
    m,r = m.divmod(1000)
    return str.insert(0,"#{r}") if m.zero?
    str.insert(0,"#{c}#{"%03d" % r}")
  end
end

separate(1)       #=>         "1"
separate(12)      #=>        "12"
separate(123)     #=>       "123"
separate(1234)    #=>     "1 234"
separate(12045)   #=>    "12 045"
separate(123456)  #=>   "123 456"
separate(1234000) #=> "1 234 000"

Hmmm. Is that column on the right tipping?

Another way that uses to_s but not join:

def separate(n, c=' ')
  str = n.to_s
  sz = str.size
  (3...sz).step(3) { |i| str.insert(sz-i, c) }
  str
end

Answer 4

I just stumbled on this thread while looking for a way to format a value as US currency. I took a slightly different approach to the regex solutions proposed:

amt = 1234567890.12
f_amt = format("$%.2f",amt)
i = f_amt.index(".")
while i > 4
  f_amt[i-3]=","+f_amt[i-3]
  i = f_amt.index(",")
end

f_amt
=> "$1,234,567,890.12"

This could be parameterized for formatting other currencies.

Answer 5

very simple:

number_with_delimiter(12500, delimiter: " ")

see: http://apidock.com/rails/ActionView/Helpers/NumberHelper/number_with_delimiter

Answer 6

Activesupport uses this regexp (and no reverse reverse).

10000000.to_s.gsub(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1 ") #=> "10 000 000"