RegExp
matcher.maches() returns false
Why this code fails ?
def matcher = "/home/me/script/test.groovy" =~ /\.groovy/ assert matcher.matches()
Because of you think you do something like "Oh dear it contains the word!", but you're confusing matches with find
From Javadoc: http://java.sun.com/j2se/1.5.0/docs/api/java/util/regex/Matcher.html#matches()
public boolean matches()
Attempts to match the entire region against the pattern.
...
So "/\.groovy/" is just a subsequence.
You must use
def matcher = "/home/me/script/test.groovy" =~ /.*\.groovy/
What is the difference between =~ and ==~ ?
- ~ is the Pattern symbol.
- =~ means matcher.find()
- ==~ means matcher.matches()
Pattern, Matcher ?
A pattern is not very usefull alone. He's just waiting input to process through a matcher.
def pattern = ~/groovy/
def matcher = pattern.matcher('my groovy buddy')
Matcher can say a lot of thing to you:
- if the entire input sequence matches the pattern, with matcher.matches() ;
- if just a subsequence of the input sequence matches the pattern, with matcher.find().
A matcher with /groovy/ pattern finds a matching subsequence in the 'my groovy buddy' sequence.
On the contrary the whole sequence doesn't match the pattern.
def m = c.matcher('my groovy buddy')
assert m.find()
assert m.matches() == false
Application: to filter a list of names.
def list = ['/a/b/c.groovy', 'myscript.groovy', 'groovy.rc', 'potatoes'] // find all items whom a subsequence matches /groovy/ println list.findAll{ it =~ /groovy/ } // => ["groovy", "/a/b/c.groovy", "myscript.groovy", "groovy.rc", "groovy."] // find all items who match exactly /groovy/ println list.findAll{ it ==~ /groovy/ } // => ["groovy"] // find all items who match fully /groovy\..*/ ('groovy' with a dot and zero or more char trailing) println list.findAll{ it ==~ /groovy\..*/ } // => ["groovy.rc", "groovy."]
A little tilde headache ? Remember like this
| ~ | the pattern |
| =~ | roughly as the pattern (easy to write) |
| ==~ | more than roughly, exactly as the pattern (think hard...) |
