Using eachDirMatch to skip .svn folders

I'm writing a program which needs to traverse a set of directories. Tried to use the following code:开发者_如何学C

file.eachDirMatch(/.*[^.svn]/){ //some code here }

But that ended up match none of my directories. I realize this boils down figuring out the right regex hang head in shame but even after revisiting some Java Regular Expression documentation I thought this should work.

Try this regex instead:

/^(?!\.svn).*/

(This assumes that your language's regex flavor supports negative lookaheads.)

You can use any expression as matcher, not just regular expression:

file.eachDirMatch({ new File(it).name != ".svn" }) { dir -> println(dir.getPath()) }

Based on Amber answer, whole thing looks like

file.eachDirMatch(~/^(?!\.svn).*/) { /* some code here */ }

For example to filter out all those hidden dirs in current directory you can use

file('.').eachDirMatch(~/^(?!\.).*/) { dir ->
    println dir.getPath()
}

To the uninitiated (to regex) this looks like gibberish. Why not just do

directories = []
file.eachDir() { File directory -> 
    if (directory.name != ".svn") {
      directories << directory
    }
}

Or if you want to ignore all hidden files do:

directories = []
file.eachDir() { File directory -> 
    if (!directory.startsWith(".")) {
      directories << directory
    }
}

One-liners are great and all, but now it's easy to read (and maintain presumably)