Java How to remove trailing and leading escape slashes in string

Question

For example, I have a string a="\\\\a\\\\b\\\\";

How to remove all escape slashes in leading and trailing for it, so the processed string will be a\\\\b .

I tried using:

a=a.replaceFirst("\\+$", "");
a=a.replaceFirst("\\+", "");

But it's not working correctly as I expected.

Answer 1

You can just use two regexes:

String a = "\\\\a\\b\\\\\\";
System.out.println(
   a.replaceAll("^\\\\+", "")
    .replaceAll("\\\\+$", "")
);

So many bars, right? This is because to express a single "\\" in a String, we need to scape it with another bar, which will be "\\\\" . But, \\ is also a special char for regular expressions, so you need to scape it too.

That is why you need four \\\\\\\\ , which will be "translated" to just two.

Answer 2

Loop through the String from start until you hit a non slash and remove slashes before it and vice versa for trailing.

I wouldn't use a regex for something this trivial.