如果第一个字符为负号，则字符串拆分，然后将其视为负号

Question

- 符号可被视为运算符或负号。如果 - 位于开头，则应将其视为负号和字符串的减法。这仅适用于 - 符号，而 + 始终是加号。我怎样才能做到这一点？

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",";"]

这是我目前尝试过的方法

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 non-digit ( \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
;

如果第一个字符为负号，则字符串拆分，然后将其视为负号

String split if the first character is minus then tread it as a negative sign

java

split

qregularexpression