java.util.regex.PatternSyntaxException: Dangling meta character ‘+’ near index 0 +

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java.util.regex.PatternSyntaxException: Dangling meta character ‘+’ near index 0 +

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  1. java.util.regex.PatternSyntaxException: Dangling meta character '+' near index 0 +

    There are reserved character in Regex and you should scape these character to achieve what you want. For example, you can't use String.split("+"), you have to use String.split("\\+").

  2. java.util.regex.PatternSyntaxException: Dangling meta character '+' near index 0 +

    There are reserved character in Regex and you should scape these character to achieve what you want. For example, you can't use String.split("+"), you have to use String.split("\\+").

Solution 1

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There are reserved character in Regex and you should scape these character to achieve what you want. For example, you can’t use String.split("+"), you have to use String.split("\\+").

The correct operators would be:

String[] operators = new String[] {"-","\\+","/","\\*","x","\\^","X"};

Original Author Paulo Of This Content

Solution 2

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in your case + * and ^ are treated with a special meaning, most often called as Metacharacters. String.split() method takes a regex expression as its argument and return a String array. To avoid treating above as a Metacharacters you need to use these escape sequences in your code "\\+" "\\*" "\\^"

modify your operator array like this

private String[] operators = new String[] {"-","\\+","/","\\*","x","\\^","X"};

for more detalis refere these links regex.Pattern and String.split()

Original Author prabath Of This Content

Solution 3

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you can use
case String.valueOf(‘+’);

Original Author saci nassim Of This Content

Solution 4

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Change: String[] split = nums.split(operator);

To this: String[] split = nums.split("\\" + operator);

edit: This will only work for standard operators, not the x or X. You’ll have to change your String[] operators declaration actually, like the other answer mentioned. Personally though, I’d do some kind of input validation and do a replace() on x or X to be * instead

Original Author j.seashell Of This Content

Conclusion

So This is all About This Tutorial. Hope This Tutorial Helped You. Thank You.

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Siddharth

I am an Information Technology Engineer. I have Completed my MCA And I have 4 Year Plus Experience, I am a web developer with knowledge of multiple back-end platforms Like PHP, Node.js, Python and frontend JavaScript frameworks Like Angular, React, and Vue.

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