Groovy : Use Collect with Initial Collection Value

The collect() method in Groovy can be used to iterate over collections and transform each element of the collection. The transformation is defined in as a closure and is passed to the collect() method. But we can also add an initial collection to which the transformed elements are added.


// Collect without
// initial collection.
assert [0,2,4,6] == (0..3).collect { it * 2 }
assert ['Groovy', 'Grails'] == [lang: 'Groovy', framework: 'Grails'].collect { it.value }

// Collect with initial collection argument.
assert [0, 1, 2, 3] == [2, 3].collect([0, 1]) { it }
assert [0, 3, 6, 9] == [2, 3].collect([0, 3], { it * 3})
assert ['Gradle', 'groovy', 'grails'] == ['Groovy', 'Grails'].collect(['Gradle']) { it.toLowerCase() }
assert ['m','r','h','a','k','i'] == [4, -3, 7, 5].collect(['m', 'r']) { (it + 100) as char }

Comments

Popular posts from this blog

I get wrong characters when retreiving the message body of an email using TIdIMAP4.UIDRetrieveTextPeek2()

How to drop the all the 1's in a correlation matrix

Today Walkin 14th-Sept