java - Java8的.map()流操作的Groovy替代方案

Question

Groovy对于Java 8的.map()的替代方案是什么？

例子:

List<String> codes = events
    .stream()
    .map(event -> event.getCode())
    .collect(Collectors.toList());

我正在尝试做

events.each { it; return it.getCode() }.collect() as String[]

但是我得到的是 List的 String，但是是 toString()表示形式而不是代码

Answer 1

考虑如下所示的collect方法:

class Event {
    def code
    def name
}

def events = []
events << new Event(code: '001', name: 'a')
events << new Event(code: '002', name: 'b')

def codes = events.collect { it.code }

assert ['001','002'] == codes

注意，等效的Groovy习惯用法是 spread-dot operator:

def codes = events*.code