rubyregexfractionsdecimal-point

Ruby Regex to round trailing zeros

I'm looking for a regex to remove trailing zeros from decimal numbers. It should return the following results:

0.0002300 -> 0.00023
10.002300 -> 10.0023
100.0     -> 100
1000      -> 1000
0.0       -> 0
0         -> 0

Basically, it should remove trailing zeros and trailing decimal point if the fraction part is 0. It should also return 0 when that's the value. Any thoughts? thanks.

Solution

  • Try the regex:

    (?:(\..*[^0])0+|\.0+)$

    and replace it with:

    \1

    A demo:

    tests = ['0.0002300', '10.002300', '100.0', '1000', '0.0', '0']
tests.each { |tst|
  print tst, " -> ", tst.sub(/(?:(\..*[^0])0+|\.0+)$/, '\1'), "\n"
}

    which produces:

    0.0002300 -> 0.00023
10.002300 -> 10.0023
100.0 -> 100
1000 -> 1000
0.0 -> 0
0 -> 0

    Or you could simply do "%g" % tst to drop the trailing zeros:

    tests = ['0.0002300', '10.002300', '100.0', '1000', '0.0', '0']
tests.each { |tst|
  s = "%g" % tst
  print tst, " -> ", s, "\n"
}

    which produces the same output.