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:"})

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

是的，使用NumberHelper。您正在寻找的方法是number_with_delimiter。

 number_with_delimiter(98765432.98, :delimiter => ",", :separator => ".")
 # => 98,765,432.98

对于javascript的人

function numberWithDelimiter(value) {
    return (value+"").split("").reverse().join("").replace(/(\d{3})(?=\d)/g, '$1,').split("").reverse().join("")
}

:)

如果您经常这样做，但也仅供参考，因为上面没有暗示它，Rails为number_with_delimiter方法提供了合理的默认值。

#inside controller or view
number_with_delimiter(2444323.4)
#=> 2,444,323.30

#inside console
helper.number_with_delimiter(233423)
#=> 233,423

如果使用最典型的方式，则不需要提供分隔符值。

对于不使用rails的人:

number.to_s.reverse.gsub(/(\d{3})(?=\d)/, '\\1,').reverse