用正则表达式分割一个简单的数学表达式 [英] Splitting a simple maths expression with regex

问题描述

我试图将正则表达式拆分为1.5 + 4.2 *（5 + 2）等运算符与运算符 - + * /所以输出将输入到数组中以便我可以单独解析

I am trying to have a regular expression split on equations like 1.5+4.2*(5+2) with operators - + * / so the output would be input into a array so I can parse individually

[0]1.5
[1]+
[2]4.2
[3]*
[4](
[5]5
[6]+
[7]2
[8]) 

我发现 \ b 将适用于 1 + 2 + 3 但是，如果我有小数点，它就不会分裂。

I have found out that the \b will work on 1+2+3 however if I were to have decimal points it would not split.

我尝试用 \ b（\.\d {1,2}）拆分但是它不会在小数点上拆分

I have tried splitting with \b(\.\d{1,2}) however it does not split on the decimal point

推荐答案

Pattern pattern = Pattern.compile("((\\d*\\.\\d+)|(\\d+)|([\\+\\-\\*/\\(\\)]))");
Matcher m = pattern.matcher("1.5+4.2*(5+2)/10-4");
while(m.find()) {
    System.out.printf("%s ", m.group());
}

output: 1.5 + 4.2 * ( 5 + 2 ) / 10 - 4

您还可以使用？：来避免捕获组。我把它留下来简单。

You can also use ?: to avoid capturing groups. I left it to make it simple.

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