您可以使用来自ActiveSupport的方法

例如:

ActiveSupport::NumberHelper::number_to_currency(10000.1234，{精度:2，单位:"})

  def add_commas(numstring)
    correct_idxs = (1..100).to_a.select{|n| n % 6 == 0}.map{|n| n - 1}
     numstring.reverse.chars.join(",").chars.select.with_index{|x, i| i.even? || correct_idxs.include?(i)}.join.reverse
  end

这就是我的红宝石之路

除了编辑: 基本上，它在数字之间添加所有逗号，只选择索引为+ 1% 6的数字

我认为逗号到100是可以的，但如果你想要一个超长的数字，就把100变成一个更高的数字

另一种不使用helper的解决方案:格式化2位小数，然后替换。由,

puts(("%.2f" % 2.5666).gsub('.',','))
>> 2,57

对于那些不使用rails处理小数的人来说，更好的方法是:

parts = number.to_s.split('.')
parts[0].gsub!(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1,")
parts.join('.')

如果需要不同的分隔符，请更改正则表达式中的最后一个'，'。

额外的，这是正则表达式的工作方式:

gsub replaces everything that matches the regex with the second parameter passed to gsub. In this case that is \\1. \\1 becomes \1 when evaluated which matches the first capture group in the regex. In this regex that is (\d). (\d)(?=(\d\d\d)+) is matching a digit followed by 1 or more groups of 3 digits. The first set of parens is our \1 capture group, the second would be \2. If we were just to leave it at that we would get: 123456.gsub!(/(\d)(?=(\d\d\d)+)/, "\\1,") #=> 1,2,3,456 This is because 1234 matches, 2345 matches and 3456 matches so we put a comma after the 1, the 2, and the 3. By adding the (?!\d) we are matching anything that comes before that doesn't precede a digit so (\d)(?=(\d\d\d)+(?!\d)) means match a digit followed by 3 digits that is not followed by a digit. The reason why this works is that gsub will keep replacing things that match the string. If we were only going to replace the first match then for a number like 123456789 we would get 123456,789. Since 123456,789 still matches our regex we get 123,456,789.

这是我得到代码的地方:https://github.com/rails/rails/blob/master/activesupport/lib/active_support/number_helper.rb#L298-L300

这里是我了解正则表达式中发生了什么的地方:http://www.tutorialspoint.com/ruby/ruby_regular_expressions.htm

新语法

number_with_delimiter(@number, delimiter: ",")

如果你想用delimeter赚钱，你可以这么做

number_to_currency(@number)

这也会增加$。如果你使用金钱宝石，那么你可以这样做

Money.new(@number,"USD").format

这也会把$。

number_with_delimiter

ruby的钱

number_to_currency

您可以使用来自ActiveSupport的方法

例如:

ActiveSupport::NumberHelper::number_to_currency(10000.1234，{精度:2，单位:"})