Remove html from only a part of string

Question

I have the following code which should remove all HTML from a part of string, which is quoted by dollar signs (could be more of them). This works fine, but I also need to preserve those dollar signs. Any suggestions, thanks

private static String removeMarkupBetweenDollars(String input){
    if ((input.length()-input.replaceAll("\\$","").length())%2!=0)
    {
        throw new RuntimeException("Missing or extra: dollar");
    }
    Pattern pattern = Pattern.compile("\\$(.*?)\\$",Pattern.DOTALL);
    Matcher matcher = pattern.matcher(input);

    StringBuffer sb =new StringBuffer();

    while(matcher.find())
         { //prepending does NOT work, if sth. is in front of first dollar
        matcher.appendReplacement(sb,matcher.group(1).replaceAll("\\<.*?\\>", ""));
        sb.append("$"); //note this manual appending
    }
    matcher.appendTail(sb);
    System.out.println(sb.toString());

    return sb.toString();
}

Thanks for help!

        String input="<p>$<em>something</em>$</p>  <p>anything else</p>";
    String output="<p>$something$</p>  <p>anything else</p>";

More complicated input and output:

String input="<p>$ bar  <b>foo</b>  bar <span style=\"text-decoration: underline;\">foo</span>  $</p><p>another foos</p> $ foo bar <em>bar</em>$";
String output="<p>$ bar  foo  bar foo  $</p><p>another foos</p> $ foo bar bar$"

I, know, but REGEX is the simpliest way to get rid of it. I don't need to do anything else with it... — MartinM
– MartinM, Commented Jul 19, 2012 at 18:52
I have no idea what you are trying to achieve. Please post sample input and expected output - examples speak much loader and clearer than words or code. And delete all your code - there's probably a better way — Bohemian
– Bohemian ♦, Commented Jul 19, 2012 at 18:52
Sorry,sample posted, I'm trying to remove all HTML which is inside 2 dollarsigns... — MartinM
– MartinM, Commented Jul 19, 2012 at 18:55

ᴇʟᴇvᴀтᴇ · Accepted Answer · 2012-07-19 19:18:21Z

1

Just some minor tweaks to your code:

private static String removeMarkupBetweenDollars(String input) {
    if ((input.length() - input.replaceAll("\\$", "").length()) % 2 != 0) {
        throw new RuntimeException("Missing or extra: dollar");
    }

    Pattern pattern = Pattern.compile("\\$(.*?)\\$", Pattern.DOTALL);
    Matcher matcher = pattern.matcher(input);

    StringBuffer sb = new StringBuffer();

    while (matcher.find()) {
        String s = matcher.group().replaceAll("<[^>]+>", "");
        matcher.appendReplacement(sb, Matcher.quoteReplacement(s));
    }
    matcher.appendTail(sb);

    return sb.toString();
}

edited Jul 19, 2012 at 19:18

answered Jul 19, 2012 at 19:12

ᴇʟᴇvᴀтᴇ

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Comments

Bohemian · Accepted Answer · 2012-07-19 19:18:29Z

0

String output = input.replaceAll("\\$<.*?>(.*?)<.*?>\\$", "\\$$1\\$");

One key point in the regex is the ? in .*? - it means a "non greedy" match, which in turn means "consume the least possible input you can". Without this, the regex would try to consume as much as possible - up to the end of a subsequent occurrence of $<html>foo</html>$ in the input if one existed.

Here's a test:

public static void main(String[] args) throws Exception {
    String input = "<p>$<em>something</em>$</p> <p>and $<em>anything</em>$ else</p>";
    String output = input.replaceAll("\\$<.*?>(.*?)<.*?>\\$", "\\$$1\\$");
    System.out.println(output);
}

Output:

<p>$something$</p> <p>and $anything$ else</p>

edited Jul 19, 2012 at 19:18

answered Jul 19, 2012 at 18:58

Bohemian♦

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6 Comments

MartinM Over a year ago

Thank you for your fast answer, but what if the input is more complicated? see my edited question?

ᴇʟᴇvᴀтᴇ Over a year ago

This works for a single embedded tag but fails if you have multiple e.g. "$something$ and $anything$ else" which returns "$something$ and $anything$ else" (wrong).

Bohemian Over a year ago

@davidpeterson Would you believe I left out a single ? from the regex. It's fixed now.

Bohemian Over a year ago

@MartinM I fixed the problem. My group one capture was also greedy - I added an extra ? to the regex and it works properly now. I also updated the sample test.

Bohemian Over a year ago

However note that your new input differs from the original in that html no longer comes immediately after the dollar.

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