如何在 Groovy 中将元素添加到列表中? [英] How do I add an element to a list in Groovy?

问题描述

假设我有一个清单，就像这样...

Let's say I've got a list, like this...

def myList = ["first", 2, "third", 4.0];

如何在元素的末尾添加(推送)一个元素?我来自 PHP 背景，在那里我会做一些类似 $myList[] = "fifth"; 的事情.Groovy 中的等价物是什么?

How do I add (push) an element to the end of it? I come from a PHP background, and there I would just do something like $myList[] = "fifth";. What's the equivalent of that in Groovy?

推荐答案

来自 文档:

我们可以通过多种方式添加到列表中:

We can add to a list in many ways:

assert [1,2] + 3 + [4,5] + 6 == [1, 2, 3, 4, 5, 6]
assert [1,2].plus(3).plus([4,5]).plus(6) == [1, 2, 3, 4, 5, 6]
    //equivalent method for +
def a= [1,2,3]; a += 4; a += [5,6]; assert a == [1,2,3,4,5,6]
assert [1, *[222, 333], 456] == [1, 222, 333, 456]
assert [ *[1,2,3] ] == [1,2,3]
assert [ 1, [2,3,[4,5],6], 7, [8,9] ].flatten() == [1, 2, 3, 4, 5, 6, 7, 8, 9]

def list= [1,2]
list.add(3) //alternative method name
list.addAll([5,4]) //alternative method name
assert list == [1,2,3,5,4]

list= [1,2]
list.add(1,3) //add 3 just before index 1
assert list == [1,3,2]
list.addAll(2,[5,4]) //add [5,4] just before index 2
assert list == [1,3,5,4,2]

list = ['a', 'b', 'z', 'e', 'u', 'v', 'g']
list[8] = 'x'
assert list == ['a', 'b', 'z', 'e', 'u', 'v', 'g', null, 'x']

你也可以这样做:

def myNewList = myList << "fifth"

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