Writing: [\/] (\ or / regex) correctly?

Question

I'm trying to write a regex that matches either \ or /.

No matter in what order I write it:

[//\]

or

[/\\]

It is somehow escaping either my square bracket or my forward slash. What's the correct way of showing this particular case?

Answer 1

Yes, you are escaping the closing bracket in the second regex, and the first one won't even compile as a string. You want

"[/\\\\]"

Both of your regex in the question are correct plain regex. However, since the regex is specified inside a Java string literal, to specify a \, you need to escape it \\. Therefore, we end up with "[/\\\\]" or "[\\\\/]".

In summary, to correctly specify \ in the regex, we must escape it \\. And to correctly specify \\ in Java string literal, we must add on another layer of escaping \\\\.