相关疑难解决方法(0)

我有一个字符串,"1/16" 我想将其转换为浮点数并乘以它45.但是,我没有得到预期的结果.

我正在努力 script/console

>> "1/16".to_f
=> 1.0
>> "1/16".to_f*45
=> 45.0

我怎样才能得到理想的结果 2.81

更大的图片:我有这样的下拉:

<%=select_tag :volume, options_for_select(["", "1 g", "1/16 oz", "1/8 oz","1/4 oz",
"1/2 oz", "1 oz", "1/8 lb", "1/4 lb", "Single", "Multi 5" ], "N/A") %>

每当用户选择oz值时,我想将它乘以45

我这样做:

first, *rest = params[:volume].to_s.split(/ /)
if rest.first=="oz"
    @indprodprice = @prods.orig_price.to_i*first.to_f*28.3495
else 
    @indprodprice = @prods.orig_price.to_i*first.to_f*453.59237
end