Regular expression to match all java operators in a string

Question

I'm working on lexical analyzing in java world, and want to break a given string into tokens discarding the spaces. I use the below regex to match tokens such as alphabet, numbers and the most common operators and separators:

"[a-zA-Z0-9_]+|[\\[\\](){}.;,!<>+^%]"

However, operators like ++ , -- , == , <= , >= ^= , *= , += is difficult to handle. Any help in how to improve my regex to fit my needs ? Many thanks.

Answer 1

Try this one:

"[a-zA-Z0-9_]|\+\+|--|<<|>>|[=+<>^*]=|[\[\](){}.;,!<>+^%]"

Explanation:

• \\+\\+ catches the ++
• -- catches the --
• << catches the <<
• >> catches the >>
• [=+<>^*]= catches == , <= , >= , ^= , *= , +=

Online test