RegularExpression for string replacement

[Gunjan Kumar]

Hi

I need one regular expression for this requirement.
I have to search for & character which is not coming before test;,in that case replace the & with &test;
Example:
input string "&abc&test;"
output string "&test;abc&test;"

input: "abc&test;"
output: "abc&test;"

input: "abc&g&test;"
output: "abc&test;g&test;"

please help me in writing the regular expression

[ May 14, 2008: Message edited by: Gunjan Kumar ]

[ May 14, 2008: Message edited by: Gunjan Kumar ]
[ May 14, 2008: Message edited by: Gunjan Kumar ]

[Campbell Ritchie]

Not easy. Please tell us what you have tried so far, and whether it works.

[Gunjan Kumar]

I have tried like this,but not able to achieve the desired output
i am not able to create a correct reg exp

    String check ="&test;hf&test";//output should be &test;hf&test;test
        Pattern p = Pattern.compile("&test;");
        // Create a matcher with an input string
        Matcher m = p.matcher(check);
        StringBuffer sb = new StringBuffer();
        boolean result = m.find();
        // Loop through and create a new String 
        // with the replacements
        while(result) {
            //System.out.println(result);
            m.appendReplacement(sb, "&GK;");
            result = m.find();
        }
        // Add the last segment of input to 
        // the new String
        m.appendTail(sb);
        System.out.println("result is "+sb.toString());

[Darryl Burke]

From your problem description, you need a regex that
-- matches the single character "&"
-- with a non-capturing zero-width negative lookahead for "test;"

And replace with "&test;"

Please go through the API for java.util.regex.Pattern and try to figure out something for yourself. Come back with your best efforts if you are unsuccessful.

edit Saw your code after I had posted that. All you need is

check.replaceAll("&(?!test :wink: ", "&test;");

[ May 14, 2008: Message edited by: Darryl Burke ]

[Gunjan Kumar]

Thanks for your reply

with a non-capturing zero-width negative lookahead for "test;"

What do you mean by non-capturing zero-width negative?

[Gunjan Kumar]

Thanks for your reply
it works for me

[Darryl Burke]

Originally posted by Darryl Burke:
From your problem description, you need a regex that
-- matches the single character "&"
-- with a non-capturing zero-width negative lookahead for "test;"

And replace with "&test;"

Please go through the API for java.util.regex.Pattern and try to figure out something for yourself. Come back with your best efforts if you are unsuccessful.

edit Saw your code after I had posted that. All you need is

check.replaceAll("&(?!test :wink:  ", "&test;");

[ May 14, 2008: Message edited by: Darryl Burke ]

edit2: Code gets replaced by smilies?
That was "&(?!test-semicolon-)"

[Joanne Neal]

Originally posted by Darryl Burke:


edit2: Code gets replaced by smilies?
That was "&(?!test-semicolon-)"

Check the 'Disable smilies in this post' check box at below left if you want to avoid this problem.

[Darryl Burke]

Originally posted by Gunjan Kumar:
What do you mean by non-capturing zero-width negative?

I repeat, please read the API for Pattern. Also The Java� Tutorial: Lesson: Regular Expressions

[Darryl Burke]

Originally posted by Joanne Neal:


Check the 'Disable smilies in this post' check box at below left if you want to avoid this problem.

Thanks for the heads-up, Joanne. @800 X 600, I hadn't ever scrolled down enough to notice it.

cheers, Darryl