swift - 当我 append 一个值时，整个数组都会更改为 append 值

Question

我在 for 循环中追加，但出于某种原因，它没有在末尾追加，而是更改了数组中的所有现有值。

let a = 2

class people {
    var name = " "
    var height = Int()
}

var trial = " "

var p = [people]() 
var user = people()
for i in 0...a-1{

    if(i==0){
        user.name =  "jack"
        user.height = 180
    }
    else {
        user.name =  "ryan"
        user.height = 120
    }

    p.append(user)
    print(p[i].name, p[i].height);

}
for i in 0...a-1 {
    print(p[i].name, p[i].height);
}

预计:-千斤顶180瑞安 120千斤顶180瑞安 120

结果:-千斤顶180瑞安 120瑞安 120瑞安 120

Answer 1

您只创建一个 instance 的 people 并将此 instance 添加到您的数组中两次。但问题是，当您第二次分配该值时，它会替换同一 instance 的先前值。

您必须在for 循环 中为每个新用户创建人 的新instnse。如下图

let a = 2

class people {
    var name = " "
    var height = Int()
}

var trial = " "

var p = [people]() 
//var user = people() remove this line from here and add inside for-loop
for i in 0...a-1{
    var user = people() // add this line here.

    if(i==0){
        user.name =  "jack"
        user.height = 180
    }
    else {
        user.name =  "ryan"
        user.height = 120
    }

    p.append(user)
    print(p[i].name, p[i].height);

}
for i in 0...a-1 {
    print(p[i].name, p[i].height);
}