在二维数组中访问相同的索引元素。

Is there a syntactical way in Swift to access the same indexed element within arrays within a 2D array, akin to accessing a column in a table, e.g.

Swift中是否有一种语法方法来访问二维数组中的相同索引元素，类似于访问表中的列，例如。

let A = [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ]

A[ 2 ]

yields [ 7, 8, 9 ]. Is there a way to do something like

产量[7,8,9]。有什么方法可以做这样的事情吗

A[][ 2 ]

yields [ 3, 6, 9 ]?

收益率[3,6,9]?

I know I can do:

我知道我能做到:

var B = [ Int ]()
for c in A {
    B.append( c[ 2 ] )
}

But I was wondering if there was another, perhaps syntactical, way.

但是我想知道是否还有另外一个，也许是句法的。

1 个解决方案

#1

Try this:

试试这个:

A.map { (elem) -> Int in
    return elem[2]
}

Or the short version (credits to @Ian):

或短片(转载@Ian):

A.map { $0[2] }