[英]How do you join two arrays in Swift combing and preserving the order of each array? (Interleaving arrays in swift)
I have two arrays and I need to preserve the order 我有两个数组,我需要保留顺序
let a = ["Icon1", "Icon2", "Icon3",]
let b = ["icon1.png", "icon2.png", "icon3.png",]
If I combine the two I get 如果我将两者结合起来
let c = a + b
// [Icon1, Icon2, Icon3, icon1.png, icon2.png, icon3.png]
How do I get the result below? 如何获得以下结果?
[Icon1, icon1.png, Icon2, icon2.png, Icon3, icon3.png]
UPDATE 12/16/2015: Not sure why I didn't recognize that flatMap was a good candidate here. 2015年12月16日更新:不知道为什么我不认识到flatMap是一个很好的候选人。 Perhaps it wasn't in the core library at the time? 也许当时它不在核心库中? Anyway the map/reduce can be replaced with one call to flatMap. 无论如何,可以通过一次调用flatMap来替换地图/缩小。 Also Zip2 has been renamed. Zip2也已重命名。 The new solution is 新的解决方案是
let c = Zip2Sequence(a,b).flatMap{[$0, $1]}
And if you run this in the swift repl environment: 并且如果您在迅速的repl环境中运行此命令:
> let c = Zip2Sequence(a,b).flatMap{[$0, $1]}
c: [String] = 6 values {
[0] = "Icon1"
[1] = "icon1.png"
[2] = "Icon2"
[3] = "icon2.png"
[4] = "Icon3"
[5] = "icon3.png"
}
Original answer below: 原始答案如下:
Here's one way I whipped together for fun 这是我一起玩耍的一种方式
let c = map(Zip2(a,b), { t in
[t.0, t.1]
})
let d = c.reduce([], +)
or inlining 或内联
let c = map(Zip2(a,b), { t in
[t.0, t.1]
}).reduce([], +)
The zipping seems unnecessary. 拉链似乎不必要。 I imagine there's a better way of doing that. 我想有一种更好的方法。 But basically, I'm zipping them together, then converting each tuple into an array, and then flattening the array of arrays. 但基本上,我将它们压缩在一起,然后将每个元组转换为一个数组,然后展平该数组。
Finally, a little shorter: 最后,简短一点:
let c = map(Zip2(a,b)){ [$0.0, $0.1] }.reduce([], +)
If both arrays are related to each other and both have the same size you just have append one at a time in a single loop: 如果两个数组相互关联且大小相同,则只需在一个循环中一次追加一个数组即可:
let a = ["Icon1", "Icon2", "Icon3"]
let b = ["icon1.png", "icon2.png", "icon3.png"]
var result:[String] = []
for index in 0..<a.count {
result.append(a[index])
result.append(b[index])
}
println(result) // "[Icon1, icon1.png, Icon2, icon2.png, Icon3, icon3.png]"
and just for the fun this is how it would look like as a function: 只是为了好玩,这就是它作为函数的样子:
func interleaveArrays<T>(array1:[T], _ array2:[T]) -> Array<T> {
var result:[T] = []
for index in 0..<array1.count {
result.append(array1[index])
result.append(array2[index])
}
return result
}
interleaveArrays(a, b) // ["Icon1", "icon1.png", "Icon2", "icon2.png", "Icon3", "icon3.png"]
May be it can help you. 可能可以帮助您。
let aPlusB = ["Icon1" : "icon1.png" , "Icon2" : "icon2.png" , "Icon3" : "icon3.png"]
for (aPlusBcode, aplusBName) in aPlusB {
println("\(aPlusBcode),\(aplusBName)")
}
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