Pattern.match() problem with $ in String

[Amrit Tiwana]

Hi,

I'm want to compare a a string against a regex. For this i m using
java.util.regex.Pattern.matches(regex, str). My problem is tht regex need not necessarily be a regex, it can be a string.
Now when I use argument like Pattern.matches("Sheet$", "Sheet$" ) it returns me false, as '$' means The end of a line(i also dont know where can I use it).

But I dont want to treat $ in string, as regex but as normal character.
please let me know the way to obtain true for input strings("Sheet$").
I tried Sheet\\p(Punct) as regex, but this will match with other strings too like Sheet* , Sheet! etc... but I want true for only exact match Sheet$.

Thanks
[ September 26, 2005: Message edited by: Amrit Tiwana ]

[Henry Wong]

Have you tried "Sheet\\$" ?

Henry

[Stan James]

Matcher has a quoteReplacement method that escapes any special characters. If your input might or might not be a regex you'd have to know when to call it and when not to. Does that help?

[Akshay Kiran]

Originally posted by Stan James:
Matcher has a quoteReplacement method that escapes any special characters. If your input might or might not be a regex you'd have to know when to call it and when not to. Does that help?

Perfectly right. If you want the string input directly (as is) as your pattern without any regex escapes, just do this
StringBuffer sb= "\Q";
sb.append(input).append("\E");
String s= sb.toString();

that should do the job (I'm not sure if we need to doubly escape \Q and \E) If this doesn't work, the thing you should do is, replace "\Q" and "\E" with "\\Q" and "\\E"

[Jim Yingst]

[Stan]: Matcher has a quoteReplacement method that escapes any special characters.

Matcher has a quoteReplacement method which escapes only \ and $ chars, because those are the only ones that have special significance for a replacement string (i.e. a string used as the second argument to String's replaceAll(), or the only argument to Matcher's replaceAll() or replaceFirst(), or the second argument to appendReplacement(). Replacement strings are a very specific context with special rules.

If you want to escape all special characters in a regex, there's \\Q and \\E as Ashkay Kiran said. Or you can use Pattern.quote(). Note that Pattern.quote() and Matcher.quoteReplacement() were added in JDK 5, while \\Q and \\E were available in 1.4.