How do I add an element to a list in Groovy?

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栀梦
栀梦 2021-01-01 08:57

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

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

How do I add (push) an element to the end of it? I c

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  •  一生所求
    2021-01-01 09:16

    From the documentation:

    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']
    

    You can also do:

    def myNewList = myList << "fifth"
    

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