Embarrassing regex question

[Aaron Fude]

Hi,

I try the following and it produces no matches:

Pattern pattern = Pattern.compile("ab*s");
Matcher matcher = pattern.matcher("abacus");

while (matcher.find()) {
System.out.println(matcher.start() + " " + matcher.end());
}


I must not understand regular expressions at all. What am I missing?

Thanks!

 

[Stefan Ram]

ab*s

This means »as«, »abs«, »abbs«, ...

 

[Eric Sosman]

I try the following and it produces no matches:

Pattern pattern = Pattern.compile("ab*s");
Matcher matcher = pattern.matcher("abacus");

while (matcher.find()) {
System.out.println(matcher.start() + " " + matcher.end());
}

I must not understand regular expressions at all. What am I missing?

What Stefan Ram said, to which I might add that you probably
want "ab.*s" as your pattern.

 

[Joshua Cranmer]

Hi,

I try the following and it produces no matches:

Pattern pattern = Pattern.compile("ab*s");
Matcher matcher = pattern.matcher("abacus");

while (matcher.find()) {
System.out.println(matcher.start() + " " + matcher.end());
}


I must not understand regular expressions at all. What am I missing?

What you are probably attempting is a form often known as "globbing" as
opposed to the standard regex or Perl-compatible regex.

 

[Roedy Green]

I try the following and it produces no matches:

You did not specify the patterns you want. For background see
http://mindprod.com/jgloss/regex.html
--
Roedy Green Canadian Mind Products
http://mindprod.com

There is no harm in being sometimes wrong especially if one is promptly found out.
~ John Maynard Keynes (born: 1883-06-05 died: 1946-04-21 at age: 62)

 

[Daniel Pitts]

Hi,

I try the following and it produces no matches:

Pattern pattern = Pattern.compile("ab*s");
Matcher matcher = pattern.matcher("abacus");

while (matcher.find()) {
System.out.println(matcher.start() + " " + matcher.end());
}


I must not understand regular expressions at all. What am I missing?

Thanks!

In regex, "*" indicates 0 or more repetitions of the previous atom. In
other words, your patter will match one 'a', followed by any number of
'b', followed by an 's'

abacus does not match that description.

You can use the '.' character, which matches any. so "ab.*s" (as
someone else has pointed out), WILL match abacus.