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JS：精度丢失0.1 + 0.2 === 0.3 ？ #56

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HCLacids opened this issue Mar 8, 2022 · 0 comments
Open

JS：精度丢失0.1 + 0.2 === 0.3 ？ #56

HCLacids opened this issue Mar 8, 2022 · 0 comments
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@HCLacids
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HCLacids commented Mar 8, 2022

参考链接

JS存放数字是双精度

pic1
pic2
双精度为存放1位为符号，11位表示指数，52位表示小数。
指数偏移量：指数偏移量公式：
formula
27.5 转换为二进制11011.1
11011.1转换为科学记数法
num
符号位0为正数1为负数
指数位e+ 或者e- 1023+/-e 这里e为4+
小数位10111补气52为最后为
0100 0000 0011 1011 1000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
0.10000000000000000555.toPrecision(16) //0.1000000000000000 去掉末尾的零后正好为0.1

恢复方式

toPrecision()
把浮点数变成整数，然后再除去基数。0.1+0.23 === (10 + 23) / 100
@HCLacids HCLacids added the JS label Mar 9, 2022
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