Java Regular expression

Question

I have a string and a pattern that I want to search for in that string. Now, when I match the pattern in the string, I want to know the string that matches my pattern.

String template = "<P ALIGN=\"LEFT\"><FONT FACE=\"Verdana\" SIZE=\"12\"> My Name is xyz </FONT></P>";

String pattern = "<FONT.*>";

Pattern.compile(pattern,Pattern.CASE_INSENSITIVE);

How can I find out the string that matches the pattern in my template.

i.e I want to get  as the result. Is there any method provided by the regex library in Java which can help me?

Update:

What is the regular expression that can match  My Name is xyz  and <LI> My Name is xyz </LI> and it should not be greedy in a given text.

HTML? Regular expressions? ? Where am I?

strager
– strager

2010-08-13 07:34:56 +00:00
Commented Aug 13, 2010 at 7:34 — strager
– strager, Commented Aug 13, 2010 at 7:34
stackoverflow.com/questions/1732348/…

Paul Tomblin
– Paul Tomblin

2010-08-16 17:59:56 +00:00
Commented Aug 16, 2010 at 17:59 — Paul Tomblin
– Paul Tomblin, Commented Aug 16, 2010 at 17:59
possible duplicate of java regular expression matching

user177800
– user177800

2010-08-17 14:35:50 +00:00
Commented Aug 17, 2010 at 14:35 — user177800
– user177800, Commented Aug 17, 2010 at 14:35

aioobe · Accepted Answer · 2010-08-13 07:38:44Z

6

You can access the matched part of the string through matcher.group() .

A more elaborate way is to use capturing groups. Put the part you want to "extract" from the matched string within parethesis, and then get hold of the matched part through, for instance matcher.group(1).

In your particular example, you need to use a reluctant qualifier for the *. Otherwise, the .* will match all the way to the end of the string (since it ends with P>).

To illustrate both the use of Matcher.group() and Matcher.group(int):

String template = "<P ALIGN=\"LEFT\"><FONT FACE=\"Verdana\" SIZE=\"12\"> My Name is xyz </FONT></P>";
String pattern = "<FONT (.*?)>";

Pattern p = Pattern.compile(pattern, Pattern.CASE_INSENSITIVE);
Matcher m = p.matcher(template);

if (m.find()) {
    // prints: <FONT FACE="Verdana" SIZE="12"> My Name is xyz </FONT></P>
    System.out.println(m.group());

    // prints: FACE="Verdana" SIZE="12"
    System.out.println(m.group(1));
}

edited Aug 13, 2010 at 7:38

answered Aug 13, 2010 at 7:27

aioobe

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15 Comments

java_geek Over a year ago

Thanks. That is helpful. I have another question. What pattern do i use to match a number in a given input?

aioobe Over a year ago

For integers? You could use for instance "\\d+".

java_geek Over a year ago

Thanks. What if there are multiple matches and i want to replace each one with some pattern??

aioobe Over a year ago

You could use String.replaceAll... it actually takes a regexp as first argument. If you need the matched string, simply refer to it as $0.

java_geek Over a year ago

i did not get what you are trying to convey. My question again Lets say there were multiple matches and i want to replace each match with a different string, how can i do that?

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