escape character nightmare - please help

[Yuriy Zilbergleyt]

Hello, I'm trying to assign the value

\"

to a String. That is, I want the string to be backslash + double quote. \" just gives the double quote, \\" becomes an unterminated string, and \\\" is back to the double quote without the backslash. I'm pretty sure that unicode would have the same result. The must be some way to do this, right?

Thanks in advance,
Yuriy

[Ernest Friedman-Hill]

This works fine:

String s = "\\\"";

From your message, that appears to be one of the things you tried, but perhaps you made a typo?

[Yuriy Zilbergleyt]

Hmm, that does work. Actually what I am really trying to do is replace all occurances of double quotes in a String with the escaped double quote. So more along the lines of

String test = "\"abc";
System.out.println(test.replaceAll("\"", "\\\""));

this just prints out "abc
I'm guessing that this is a regular expression problem then?

Thanks in advance,
Yuriy

[Ernest Friedman-Hill]

Originally posted by Yuriy Zilbergleyt:

I'm guessing that this is a regular expression problem then?

Yes. It's tricky because the backslash is meaningful to both Java and the regexp parser. To do this, first write the actual expression you want to replace with:

\\"

Then escape each of the special characters so they'll pass through the Java parser untouched:

\\\\\"

So you need to say

System.out.println(test.replaceAll("\"", "\\\\\""));

Five slashes!

[Yuriy Zilbergleyt]

Great! Thank you so much!

Yuriy

[Layne Lund]

Your subject name aptly names your problem. When dealing with regular expressions, escape characters are definitely nightmarish!

Layne

[Stefan Wagner]

It helps to read regular expressions containing special characters from a file or a textfield, and to control them by printing them out.