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

几乎每个人都给出了如何直接,让我来展示一下演变:

你可以使用Array的实例方法:

// general form of closure
images.sortInPlace({ (image1: imageFile, image2: imageFile) -> Bool in return image1.fileID > image2.fileID })

// types of closure's parameters and return value can be inferred by Swift, so they are omitted along with the return arrow (->)
images.sortInPlace({ image1, image2 in return image1.fileID > image2.fileID })

// Single-expression closures can implicitly return the result of their single expression by omitting the "return" keyword
images.sortInPlace({ image1, image2 in image1.fileID > image2.fileID })

// closure's argument list along with "in" keyword can be omitted, $0, $1, $2, and so on are used to refer the closure's first, second, third arguments and so on
images.sortInPlace({ $0.fileID > $1.fileID })

// the simplification of the closure is the same
images = images.sort({ (image1: imageFile, image2: imageFile) -> Bool in return image1.fileID > image2.fileID })
images = images.sort({ image1, image2 in return image1.fileID > image2.fileID })
images = images.sort({ image1, image2 in image1.fileID > image2.fileID })
images = images.sort({ $0.fileID > $1.fileID })

关于排序的工作原理的详细解释,请参见排序函数。

其他回答

首先,将Array声明为类型化数组,以便在迭代时调用方法:

var images : [imageFile] = []

然后你可以简单地做:

斯威夫特2

images.sorted({ $0.fileID > $1.fileID })

斯威夫特3

images.sorted(by: { $0.fileID > $1.fileID })

斯威夫特5

images.sorted { $0.fileId > $1.fileID }

上面的例子按降序给出了结果。

如果您想对自定义对象的原始数组进行排序。在Swift 2.1中有另一种方法

var myCustomerArray = [Customer]()
myCustomerArray.sortInPlace {(customer1:Customer, customer2:Customer) -> Bool in
    customer1.id < customer2.id
}

其中id为整数。您也可以对String属性使用相同的<操作符。

你可以通过下面的例子了解更多关于它的用法: Swift2:附近的顾客

斯威夫特3

people = people.sorted(by: { $0.email > $1.email })

你也可以这样做

images = sorted(images) {$0.fileID > $1.fileID}

你的图像数组会以排序的方式存储

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)