Javascript >= 与两个负数比较产生不正确的结果

Question

I've come across strange behaviour where both before and after using toFixed() the same number is visibly greater than the other (correct).我遇到了奇怪的行为，在使用 toFixed() 之前和之后，相同的数字明显大于另一个（正确）。 However the toFixed() version produces an incorrect comparison?但是 toFixed() 版本会产生不正确的比较？ This seems to happen when both numbers are negative and >= is the operand.当两个数字都是负数并且 >= 是操作数时，这似乎会发生。

 let lastVal = 0.091; let currentVal = 0.093; let newVal = 0.094; let oldSlope = lastVal - currentVal; let newSlope = currentVal - newVal; let oldSlopeFixed = (lastVal - currentVal).toFixed(16); let newSlopeFixed = (currentVal - newVal).toFixed(16); document.getElementById("one").innerHTML = "oldSlope = " + oldSlope + ", newSlope = " + newSlope; document.getElementById("two").innerHTML = "oldSlopeFixed = " + oldSlopeFixed + ", newSlopeFixed = " + newSlopeFixed; if ((newSlope) >= (oldSlope)) { document.getElementById("three").innerHTML = "newSlope >= oldSlope (correct)"; } if (!((newSlopeFixed) >= (oldSlopeFixed))) { document.getElementById("four").innerHTML = "newSlopeFixed < oldSlopeFixed (incorrect ... what???)"; }

 <!DOCTYPE html> <html> <body> <p id="one"></p> <p id="two"></p> <p id="three"></p> <p id="four"></p> </body> </html>

Answer 1

toFixed produces a string. toFixed产生一个字符串。 You aren't comparing numbers, you're comparing strings, which are compared alphabetically.您不是在比较数字，而是在比较按字母顺序比较的字符串。

 console.log(-0.001 <= -0.002) // false console.log('-0.001' <= '-0.002') // true

Don't use toFixed before calculations.不要在计算前使用toFixed 。 It is used when all calculations are done and you're trying to format a number for human consumption.当所有计算完成并且您尝试格式化数字以供人类使用时使用它。

Javascript >= 与两个负数比较产生不正确的结果

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1 个解决方案

解决方案1
4 已采纳 2022-05-19 14:58:53

Javascript &gt;= 与两个负数比较产生不正确的结果

问题描述

1 个解决方案

解决方案1 4 已采纳 2022-05-19 14:58:53

Javascript >= 与两个负数比较产生不正确的结果

解决方案1
4 已采纳 2022-05-19 14:58:53