Groovy "List Comprehension" example

def paramNames  = request.getParameterNames().collect { it }
def paramValues = request.getParameterNames().collect { request.getParameter(it) }
 
// -----------------------------------------------
def getEvenNumbers(l) {
        l.findAll {it % 2 == 0}
    }
 
    def getFilesGreaterThan(size, folder) {
        new File(folder).listFiles().findAll {it.isFile() && it.length() > size}
    }
 
    def solveProblem() {
        (1..9).each { a->
            (0..9).each { b->
                (0..9).each { c->
                    (0..9).each { d->
                        if ((1000*a + 100*b + 10*c + d)*4 == 1000*d +100*c + 10*b + a) {
                            println "$a, $b, $c, $d"
                        }
                    }
                }
            }
        }
    }