Hi all, my name is Hubert A. Klein Ikkink. Not a very common name, right? To make things easier I just picked the first letters of my firstname and surname and came up with haki. So there you have it, now I am also known as Mr. Haki or mrhaki for short. You can read more blog postings at www.mrhaki.com. I am a passionate Groovy and Java developer based in Tilburg, The Netherlands. My goal is to write clean, elegant, user-centered and high quality software. You can find me on Google+ and Twitter. Hubert is a DZone MVB and is not an employee of DZone and has posted 151 posts at DZone. You can read more from them at their website. View Full User Profile

Groovy Goodness: Drop or Take Elements with Condition

10.10.2012
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In Groovy we can use the drop() and take() methods to get elements from a collection or String object. Since Groovy 1.8.7 we also can use the dropWhile() and takeWhile() methods and use a closure to define a condition to stop dropping or taking elements. With the dropWhile() method we drop elements or characters until the condition in the closure is true. And the takeWhile() method returns elements from a collection or characters from a String until the condition of the closure is true.

In the following example we see how we can use the methods:

def s = "Groovy Rocks!"

assert s.takeWhile { it != 'R' } == 'Groovy '
assert s.dropWhile { it != 'R' } == 'Rocks!'


def list = 0..10

assert 0..4 == list.takeWhile { it < 5 }
assert 5..10 == list.dropWhile { it < 5 }


def m = [name: 'mrhaki', loves: 'Groovy', worksAt: 'JDriven']

assert [name: 'mrhaki'] == m.takeWhile { key, value -> key.length() == 4 }
assert [loves: 'Groovy', worksAt: 'JDriven'] == m.dropWhile { it.key == 'name' }

(Code is written with Groovy 2.0.4)

 
Published at DZone with permission of Hubert Klein Ikkink, author and DZone MVB. (source)

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