java如何检查两个双值中的较大值和较小值？

Question

我有两个double值，我想通过比较这两个值来检查是否等于或大于和是否等于或小于

我在网上找不到相关的问题，所以我也找不到答案

我所能找到的就是，如何比较两个double值

     int returnVal = Double.compare(d1, d2);

但是我如何检查d1 <= d2和d1 >= d2

编辑：

double remRangeInKm;
if (remRange == 200 || remRange == 500){
     if (remRange == 200) remRangeInKm = 0.2;
     else remRangeInKm = 0.5;
}
else remRangeInKm = remRange * 1.0;

int earthRadius = 6371; //in km
double distance = Math.abs(Math.acos(Math.sin(remLatitude)*Math.sin(currentLatitude)
              + Math.cos(remLatitude)*Math.cos(currentLatitude)
              * Math.cos(currentLongitude - remLongitude)) * earthRadius);

Log.d("Distance after formula", String.valueOf(distance));

if (distance <= remRangeInKm){
    triggerNotification();
}

距离是91.482605 meters，remRangeInKm是200 meters，即使它没有执行if语句

Answer 1

int returnVal = Double.compare(d1, d2);     
boolean lessThanOrEqual = returnVal <= 0;

Answer 2

int returnVal = Double.compare(d1, d2);

这会满足您的需要并返回：

如果d1在数值上等于d2，则值为0；如果d1在数值上小于d2，则值小于0；如果d1在数值上大于d2，则该值大于0

Answer 3

请尝试使用BigDecimal，如下例所示

import java.math.BigDecimal; BigDecimal premium = BigDecimal.valueOf(1586.6d); BigDecimal netToCompany = BigDecimal.valueOf(708.75d); BigDecimal commission = premium.subtract(netToCompany); System.out.println(commission + " = " + premium + " - " + netToCompany);

这将产生以下输出

877.85 = 1586.6 - 708.75

可能重复：How to resolve a Java Rounding Double issue

Answer 4

这需要一些修正，这里有死代码：

double remRangeInKm;
if (remRange == 200 || remRange == 500){
     if (remRange == 200) remRangeInKm = 0.2;
     else remRangeInKm = 0.5;
}
else remRangeInKm = remRange * 1.0;

固定的：

double remRangeInKm = 0.0;
if (remRange == 200 || remRange == 500) {
     if (remRange == 200) { 
         remRangeInKm = 0.2;
     } else {
         remRangeInKm = 0.5;
     }
} else {
    // there was a logic mistake here, needs to be multiplied by 0.001 
    // not 1.0 to convert from meters to km
    // if you have 600m * 1.0 == 600.0km
    // should be 600m * 0.001 == 0.6km
    remRangeInKm = remRange * 0.001;
}

现在尝试使用此修复程序运行代码

注意：如果使用if/else的括号，则更容易遵循逻辑并理解每种情况下发生的情况

Answer 5

那么：

double d1 = 1.0;
double d2 = 2.0;
if (d1 <= d2) {
   System.out.println(d1 + " is lesser than " + d2);
}

这适用于Double：编译器将根据需要执行box/unbox操作。当然你也可以用另一种方式

if (d2 >= d1) {
   System.out.println(d1 + " is lesser than " + d2);
}

Answer 6

这就行了

// true if d1 is equal or smaller than d2
Double.compare(d1, d2) <= 0

// true if d1 is equal or larger than d2
Double.compare(d1, d2) >= 0