在mongodb中舍入到小数点后2位 [英] Rounding to 2 decimal places in mongodb
问题描述
我的收藏为
学生
{
"first_name":"Harew",
"last_name":"Jackson",
"class":14,
"fee": [
{ "tuition":48500.2456, "transportation":500 }
]
}
我需要根据fee = 4500.24
过滤学生,并显示
所有有费用4500.24的学生都忽略了小数点后的其他数字.
I need to filter student according to fee = 4500.24
and it should display
all the students having fee 4500.24 ignoring other digits after the decimal point.
我已经搜索了 MongoDB:如何在查询中获得N个小数精度
查询精度,但是此处提供的解决方案在我的情况下不起作用,因为
"$mod": [ "$amount.value", 0.01 ]
不适用于BigDecimal
类型,在我的收藏中,我的费用类型为BigDecimal
.
I have searched in MongoDB: How to get N decimals precision in a query
precision-in-a-query but the solution provided here does not work in my scenario since
"$mod": [ "$amount.value", 0.01 ]
is not applicable for BigDecimal
type and in my collection I have fee type as BigDecimal
.
以下解决方案似乎效果很好,但我不知道如何在Scala中实现该功能
The following solution seems to work well but I don't know how to implement this in Scala
db.collection.find({
"$where": function() {
return Math.round(this.fee.school * 100)/ 100 === 1.12;
}
})
推荐答案
您可以轻松地将这些值从BigDecimal中舍入为特定精度,也可以同时将其转换为double值. 例如:-
you can easily round up the values into specific precision from BigDecimal , also if you want you can convert it into double value at the same time . For Example : -
scala> val s:BigDecimal = 10.232 s:BigDecimal = 10.232
scala> val s :BigDecimal = 10.232 s: BigDecimal = 10.232
scala> s.setScale(2,BigDecimal.RoundingMode.HALF_UP).toDouble res1:Double = 10.23//转换为Double
scala> s.setScale(2, BigDecimal.RoundingMode.HALF_UP).toDouble res1: Double = 10.23 // CONVERTED AS DOUBLE
scala> s.setScale(2,BigDecimal.RoundingMode.HALF_UP) res2:scala.math.BigDecimal = 10.23//正在路由
scala> s.setScale(2, BigDecimal.RoundingMode.HALF_UP) res2: scala.math.BigDecimal = 10.23 // Rouding Off
因此在scala中,而不是使用math.Round,您可以使用setScale.
So in scala instead of using math.Round you can use setScale.
这篇关于在mongodb中舍入到小数点后2位的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!