假设我们有一个名为imageFile的自定义类，这个类包含两个属性:
class imageFile {
var fileName = String()
var fileID = Int()
}
很多都存储在一个数组中:
var images : Array = []
var aImage = imageFile()
aImage.fileName = "image1.png"
aImage.fileID = 101
images.append(aImage)
aImage = imageFile()
aImage.fileName = "image1.png"
aImage.fileID = 202
images.append(aImage)
我如何排序的图像数组由'fileID'升序或降序?
当前回答
斯威夫特3、4、5所示
struct imageFile {
var fileName = String()
var fileID = Int()
}
//append objects like this
var arrImages = [imageFile]()
arrImages.append(.init(fileName: "Hello1.png", fileID: 1))
arrImages.append(.init(fileName: "Hello3.png", fileID: 3))
arrImages.append(.init(fileName: "Hello2.png",fileID: 2))
//array sorting using below code
let sortImagesArr = arrImages.sorted(by: {$0.fileID < $1.fileID})
print(sortImagesArr)
//output
imageFile(fileName: "Hello1.png", fileID: 1),
imageFile(fileName: "Hello2.png", fileID: 2),
imageFile(fileName: "Hello3.png", fileID: 3)
其他回答
Swift 3 & 4 & 5
我遇到了一些关于小写和大写的问题
所以我写了这个代码
let sortedImages = images.sorted(by: { $0.fileID.lowercased() < $1.fileID.lowercased() })
然后使用sortedImages
[为Swift 3更新了sort(by:)]这，利用一个尾随闭包:
images.sorted { $0.fileID < $1.fileID }
根据ASC或DESC分别使用<或>。如果你想修改图像数组，那么使用以下命令:
images.sort { $0.fileID < $1.fileID }
如果你要重复这样做，并且更喜欢定义一个函数，一种方法是:
func sorterForFileIDASC(this:imageFile, that:imageFile) -> Bool {
return this.fileID < that.fileID
}
然后用as:
images.sort(by: sorterForFileIDASC)
在Swift 3.0中
images.sort(by: { (first: imageFile, second: imageFile) -> Bool in
first. fileID < second. fileID
})
如果你要在多个地方对这个数组排序，让你的数组类型Comparable是有意义的。
class MyImageType: Comparable, Printable {
var fileID: Int
// For Printable
var description: String {
get {
return "ID: \(fileID)"
}
}
init(fileID: Int) {
self.fileID = fileID
}
}
// For Comparable
func <(left: MyImageType, right: MyImageType) -> Bool {
return left.fileID < right.fileID
}
// For Comparable
func ==(left: MyImageType, right: MyImageType) -> Bool {
return left.fileID == right.fileID
}
let one = MyImageType(fileID: 1)
let two = MyImageType(fileID: 2)
let twoA = MyImageType(fileID: 2)
let three = MyImageType(fileID: 3)
let a1 = [one, three, two]
// return a sorted array
println(sorted(a1)) // "[ID: 1, ID: 2, ID: 3]"
var a2 = [two, one, twoA, three]
// sort the array 'in place'
sort(&a2)
println(a2) // "[ID: 1, ID: 2, ID: 2, ID: 3]"
如果你不使用自定义对象，而是使用值类型来实现可比协议(Int, String等)，你可以简单地这样做:
myArray.sort(>) //sort descending order
一个例子:
struct MyStruct: Comparable {
var name = "Untitled"
}
func <(lhs: MyStruct, rhs: MyStruct) -> Bool {
return lhs.name < rhs.name
}
// Implementation of == required by Equatable
func ==(lhs: MyStruct, rhs: MyStruct) -> Bool {
return lhs.name == rhs.name
}
let value1 = MyStruct()
var value2 = MyStruct()
value2.name = "A New Name"
var anArray:[MyStruct] = []
anArray.append(value1)
anArray.append(value2)
anArray.sort(>) // This will sort the array in descending order
