有没有办法以百分比的形式打印十进制数,所以只能在句点后面的两位数字？
我的小数总是在1到0之间,所以我想可以从第三个字符开始调用number.round(2),但是我找不到任何地方的语法.
为了澄清,我想要将数字存储为一个完整的十进制,但是以百分比打印.
解决方法
你可能要使用number_to_percentage方法.这里有一些如何使用它的例子.
number_to_percentage(100) # => 100.000%
number_to_percentage("98") # => 98.000%
number_to_percentage(100,precision: 0) # => 100%
number_to_percentage(1000,delimiter: '.',separator: ',') # => 1.000,000%
number_to_percentage(302.24398923423,precision: 5) # => 302.24399%
number_to_percentage(1000,locale: :fr) # => 1 000,000%
number_to_percentage("98a") # => 98a%
number_to_percentage(100,format: "%n %") # => 100 %
选项：
:locale - Sets the locale to be used for formatting (defaults to current locale). :precision - Sets the precision of the number (defaults to 3). :significant - If true,precision will be the # of significant_digits. If false,the # of fractional digits (defaults to false). :separator - Sets the separator between the fractional and integer digits (defaults to “.”). :delimiter - Sets the thousands delimiter (defaults to “”). :strip_insignificant_zeros - If true removes insignificant zeros after the decimal separator (defaults to false). :format - Specifies the format of the percentage string The number field is %n (defaults to “%n%”).
或者你可以写一些如下的ruby：
class Numeric
def percent_of(n)
self.to_f / n.to_f * 100.0
end
end
p (1).percent_of(10) # => 10.0 (%)
p (200).percent_of(100) # => 200.0 (%)
p (0.5).percent_of(20) # => 2.5 (%)