Java regex doesn't work

Question

Having a slight regex problem. I wrote to following code to check if a word is contained within a String.

boolean matches = Pattern.matches("\\b" + Pattern.quote(item.name) + "\\b", nap.code);

item.name will be something like "half" nap.code will be something like "int halfOfFour() { return half(4); }"

Yet, my pattern match returns false... What am I doing wrong here?

Also... Is there anyway to make this return false if the word is contained within a string?

Markus Mikkolainen · Accepted Answer · 2012-08-02 09:24:12Z

3

I think the pattern match will match the whole string not just a part of it. so prefix with .* and postfix with .* or something.

use pattern and matches separately and then use "find()" in matcher to find submatches

answered Aug 2, 2012 at 9:24

Markus Mikkolainen

3,50720 silver badges21 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

Markus Mikkolainen Over a year ago

of course i assume that you dont want to use string contains or indexOf/lastIndexOf

LiuYan 刘研 Over a year ago

System.out.println ("int halfOfFour() { return half(4); }".matches(".*\\bhalf\\b.*")); --> true

Robin Heggelund Hansen Over a year ago

"testfunc passing() { int halfOfFour = half(4); assert(halfOfFour == 2, "The laws of physics is on break"); }".matches(".*\\b" + Pattern.quote("half") + "\\b.*"); Still results in false...

Markus Mikkolainen Over a year ago

then you need to use the pattern/matcher separately to find submatches.

Markus Mikkolainen Over a year ago

try ".*\\W+"+pattern.quote(item.name)+"\\W+.*" or something.

|

kgautron · Accepted Answer · 2012-08-02 10:10:28Z

1

Wouldn't the Java.lang.String.contains() method do what you want?

boolean contains = nap.code.contains(item.name);

EDIT : To return true only if the word is present, using the \W pattern (non-word character) should help you :

\W*(YOUR_WORD)\W*

edited Aug 2, 2012 at 10:10

answered Aug 2, 2012 at 9:24

kgautron

8,34510 gold badges42 silver badges61 bronze badges

5 Comments

Martijn Courteaux Over a year ago

No, he wants to check if a full word is in the string. Canon contains non, but it is not a word. CaNon contains the word non.

kgautron Over a year ago

In his example (half/halfOfHour) he says it should return true despite 'half' not being a full word. So I think you misread that.

Martijn Courteaux Over a year ago

Yes, but I think he is really looking for a way to check words. The capital characters mark the beginning of a word.

Robin Heggelund Hansen Over a year ago

Actually, i want it to return true because the string includes "half(4)"... "halfOfFour" should still return false.

Robin Heggelund Hansen Over a year ago

Like this? boolean matches = nap.code.matches("\\W*" + Pattern.quote(item.name) + "\\W*"); Cause that still does not work...

Collectives™ on Stack Overflow

Java regex doesn't work

2 Answers 2

6 Comments

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

6 Comments

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related