如何分割2个部分的字符串？

I am working on a linear system solver and I would like the user to be able to input the whole equation in one go as oppose to separately inputting each number.

我正在研究线性系统求解器,我希望用户能够一次性输入整个等式,而不是分别输入每个数字。

I have tried to split the string at the "+" and "=" (The equation format is (ax+by=c)) but it is splitting the second part after the plus as "by=c" rather than just "by".

我试图将字符串拆分为“+”和“=”(等式格式为(ax + by = c))但是它将加号之后的第二部分拆分为“by = c”而不仅仅是“by” ”。

Here is my code:

这是我的代码:

System.out.print("Enter Your First Equation (ax + by = c): " );
String eq1 = sc.nextLine();

String[] part = eq1.split("\\+");
String[] part2 = eq1.split("\\=");

String result = part[0];

String result2 = part[1];

String result3 = part2[1];


double a1 = Double.parseDouble(result);
double b1 = Double.parseDouble(result2);
double c1 = Double.parseDouble(result3);

System.out.print("Enter Your Second Equation (ax + by = c): " );
String eq2 = sc.nextLine();

String[] part3 = eq1.split("\\+");
String[] part4 = eq1.split("\\=");

String result4 = part3[0];

String result5 = part3[1];

String result6 = part4[1];

double a2 = Double.parseDouble(result4);
double b2 = Double.parseDouble(result5);
double c2 = Double.parseDouble(result6);


System.out.println("Your Equations Are (1) " + a1 + "x + " + b1 + "y = " + c1);
System.out.println("                   (2) " + a2 + "x + " + b2 + "y = " + c2);

2 个解决方案

#1

String.split won't give you the desired result, which I guess would be "ax", "by", since it would have to look for a token to split at and would strip that token.

String.split不会给你想要的结果,我猜这将是“ax”,“by”,因为它必须寻找分裂的标记并将剥离该标记。

Try Pattern and Matcher instead, using this regex: (\d*)([a-zA-Z]+)|(\d+).

尝试模式和匹配,使用此正则表达式:(\ d *)([a-zA-Z] +)|(\ d +)。

e.g:

public static void main(String[] args) {

        String exp = "53x+6y=30";

        String pattern = "(\\d*)([a-zA-Z]+)|(\\d+)";

        // Create a Pattern object
          Pattern r = Pattern.compile(pattern);

          // Now create matcher object.
          Matcher m = r.matcher(exp);

          while (m.find( )) {
             System.out.println("Found value: " + m.group(0) );
          }
    }

Output -

Found value: 53x
Found value: 6y
Found value: 30

#2

If you insist on using the String.split() method then I suppose you could do it like this (just as an example):

如果你坚持使用String.split()方法,那么我想你可以像这样做(仅作为例子):

String eq = "ax+by=c";
String[] splitStrg1 = eq.split("=");
String[] splitStrg2 = splitStrg1[0].split("\\+");
String part1 = splitStrg2[0];
String part2 = splitStrg2[1];
String part3 = splitStrg1[1];

System.out.println("Part 1 is: " + part1);
System.out.println("Part 2 is: " + part2);
System.out.println("Part 3 is: " + part3);

#1