从自定义类填充数组的最简单方法？

发布于 2024-09-09 00:17:06 字数 204 浏览 4 评论 0原文

假设您有一个 Person 类（包含姓名、年龄等），以及一个名为 PeopleArray 的数组，其中包含多个单独的 Person。

提取每个人的姓名（例如）并将其放入数组中的最简单方法是什么。伪代码是：

nameArray = every Person's name, from the array PeopleArray

原文

Say you have a class Person (with name, age, etc), and an array called PeopleArray which has several individual Person's.

What's the easiest way of extracting each Person's name (for instance) and putting it into an array.
Psuedocode is:

nameArray = every Person's name, from the array PeopleArray

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何以畏孤独 2024-09-16 00:17:06

编辑：我找到了比我之前发布的答案更好的解决方案

NSArray* names = [peopleArray valueForKey: @"name"];

将 -name 发送到 peopleArray 的每个元素并构建一个新的结果数组

文档

一种方法，使用快速枚举：

NSMutableArray* nameArray = [[NSMutableArray alloc] init];
for (Person* person in peopleArray)
{
    [nameArray addObject: [person name]];

}

另一种方法，将我的答案与我之前发布的相同答案区分开来:-)

在 Person 上创建一个名为 addNameToArray: 的方法并使用 makeObjectsPerformSelector:

// Person.m

-(void) addNameToArray: (id) aMutableArray
{
    [aMutableArray addObject: [self name]];
}

// where you want to add the names

NSMutableArray* nameArray = [[NSMutableArray alloc] init];
[peopleArray makeObjectsPerformSelector: @selector(addNameToArray:) withObject: nameArray];

~~令人失望的是，似乎没有与地图功能等效的方法。 s>~~

Edit: I've found a better solution than the answers I previously posted

NSArray* names = [peopleArray valueForKey: @"name"];

Sends -name to every element of peopleArray and builds a new array of the results

Documentation

One way, use fast enumeration:

NSMutableArray* nameArray = [[NSMutableArray alloc] init];
for (Person* person in peopleArray)
{
    [nameArray addObject: [person name]];

}

Another way, to distinguish my answer from the identical one posted just before mine :-)

Create a method on Person called addNameToArray: and use makeObjectsPerformSelector:

// Person.m

-(void) addNameToArray: (id) aMutableArray
{
    [aMutableArray addObject: [self name]];
}

// where you want to add the names

NSMutableArray* nameArray = [[NSMutableArray alloc] init];
[peopleArray makeObjectsPerformSelector: @selector(addNameToArray:) withObject: nameArray];

~~Disappointingly there seems to be no equivalent to the map function.~~

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冬天旳寂寞 2024-09-16 00:17:06

NSMutableArray *nameArray = [[NSMutableArray alloc] init];
for (Person *person in peopleArray) {
    [nameArray addObject:person.name];
}

NSMutableArray *nameArray = [[NSMutableArray alloc] init];
for (Person *person in peopleArray) {
    [nameArray addObject:person.name];
}

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爱你是孤单的心事 2024-09-16 00:17:06

NSMutableArray *nameArray = [NSMutableArray arrayWithCapacity:0]; // autoreleased, so no leak
for (Person *peep in peopleArray) {  
    [nameArray addObject:peep.name]; // assumes you made name a property  
}

NSMutableArray *nameArray = [NSMutableArray arrayWithCapacity:0]; // autoreleased, so no leak
for (Person *peep in peopleArray) {  
    [nameArray addObject:peep.name]; // assumes you made name a property  
}

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~没有更多了~