Getting groovy - an introduction to the Groovy language

Iterating over each entry in a collection

Probably the most basic case for iteration is to perform an operation on each element of a collection. In groovy this is performed using each. Each can be applied to many types, here we will consider a Map, as we saw a list example on the previous page.

def addressByName = [ 'dave' : 'some address', 'joe' : 'another address']

addressByName.each { key, value ->
    println "${key} ${value}"
}

Notice in the above example that the closure take two parameters; which are the key and value of each entry in the map.

Joining all the items in a collection

Sometimes all items in a collection need to be joined together, for example a list of names that is comma separated. Groovy provides join for this:

def nameList = ['dave', 'joe', 'fred']

println "${nameList.join(',')}"

Creating a new collection from a collection

The last case this article considers creating another collection from the existing one. In groovy this is done using collect.

def nameList = ['dave', 'joe', 'fred']

def outputList = nameList.collect {
    n ->
    "name is ${n}"
}

outputList.each {n -> println n}

Groovy - next steps

Well that ends the whirlwind tour of groovy. I hope that this article has given you a good insight into this promising language. Don't forget that this article has only scratched the surface of whats available with groovy, take a look at some of our more indepth articles or get a good groovy book to delve deeper.