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javaregexstringreplaceall

string.replaceAll java doesn't work with lookaround regex?

I have a json string like this:

string = "{name={first=sam, last=vo}, hobbies={hobby1=football, hobby2=swimming}}"

And I want to remove the "name=" and the "hobbies=", so that I use this pattern: \w*\=(?={) ->tested using editPadPro

However, when I use the replace all in java:

String pattern = "\\w*\\=(?={)";
String removedParent = string.replaceAll(pattern, "");

I got this error message 

"Exception in thread "main" java.util.regex.PatternSyntaxException: Illegal repetition near index 7
\w*\=(?={)"

Can you please give me some advices to get this work?

Regards,

Sam

Solution

  • The problem is that the { character is a special character in regex syntax which denotes an amount (for instance \d{2} denotes 2 digits). In your case, you want to match the literal {, meaning that you need to escape the { character, so you need to change your regex to this: "\\w*\\=(?=\\{)";.

    For me, this yielded:

    {{first=sam, last=vo}, {hobby1=football, hobby2=swimming}}