字符串拆分：如果第一个字符是负号，则将其作为负号处理

Question

-符号可以被视为运算符或负号。如果-位于开始，则应将其视为负号和抹去字符串的减法。这仅适用于-符号，而将始终是加号。如何实现此目的？

输入:

-23-23+4=F1Qa;
+23-23+4=F1Qa;

输出：

["-23","-","23","+","4","=","F","1","Q","a",";"]
["+", "23","-","23","+","4","=","F","1","Q","a",";"]

到目前为止我一直在尝试

String regx = (?:# .*? #:?)|(?!^)(?=\\D)|(?<=\\D)(?=\\d-)
String[] splits = inputString.split(regx);

Answer 1

您可以使用正则表达式，^-\d|\d\d表示开头为负整数（即^-\d）或数字（即\d ），或非数字（\d）。

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {

    public static void main(String[] args) {
        String str = "-23-23+4=F1Qa;";
        Pattern pattern = Pattern.compile("^-\\d+|\\d+|\\D");
        Matcher matcher = pattern.matcher(str);
        while (matcher.find()) {
            System.out.println(matcher.group());
        }
    }
}

输出：

-23
-
23
+
4
=
F
1
Q
a
;

另一个测试：

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {

    public static void main(String[] args) {
        String str = "+23-23+4=F1Qa;";
        Pattern pattern = Pattern.compile("^-\\d+|\\d+|\\D");
        Matcher matcher = pattern.matcher(str);
        while (matcher.find()) {
            System.out.println(matcher.group());
        }
    }
}

输出：

+
23
-
23
+
4
=
F
1
Q
a
;