To find all items matching a condition in a collection, use the findAll() function. It
accepts a boolean closure identifying the items you're looking for.
The result is a
List
of all items in the collection for which the
closure evaluates to
true
. If no item matches or the collection is
empty, then an empty collection is returned.
As shown below, you can leave off the parentheses if passing the closure in-line. The
result of this example is a list containing all recipient emails whose address ends with
the
.edu
suffix:
def recipients = ['sjc@example.edu','dan@example.com',
'spm@example.edu','jim@example.org']
// Pass boolean closure using implicit "it" parameter with find criteria
// (using safe-navigation operator in case any element is null)
def eduAddreses = recipients.findAll{ it?.endsWith('.edu') }
When applied to a
List
of
Map
objects, your closure can
reference the current map's keys by name as shown below. This example produces a list of
phonebook entries having a phone number that starts with the country code "+39-" for
Italy.
def phonebook = [
[name: 'Steve', phone: '+39-123456789'],
[name: 'Joey', phone: '+1-234567890'],
[name: 'Sara', phone: '+39-345678901'],
[name: 'Zoe', phone: '+44-456789123']
def italianFriends = phonebook.findAll { it?.phone?.startsWith('+39-') }
If you call
findAll()
on a
Map
, then the parameter
passed to the closure on each evaluation is the current
Map
entry. Each
entry has a
key
and
value
property you can reference
in the closure function body if necessary. The result is a
Map
containing only the entries for which the closure evaluates to true. In the example
below, the result is a map containing the two users' map entries whose
name
is
Steve
.
def users = [
'smuench':[name:'Steve', badge:'A123'],
'jevans':[name:'Joe', badge:'B456'],
'sburns':[name:'Steve', badge:'C789']
def usersNamedSteve = users.findAll { it?.value.name == 'Steve' }
To find only the
first
matching item, use the
find()
function instead of
findAll()
. It accepts the same boolean closure but
stops when the first match is identified. Note that in contrast to
findAll()
, when using
find()
if no item matches
the predicate or the collection was empty to begin with then
null
is
returned.
Companion functions exist to perform other searching operations
like:
any {
boolean_predicate
}
— returns true if
boolean_predicate
returns
true
for any item
