[OC Foundation框架

 NSArray是不可变的，不能先创建再添加元素

NSArray可以放入任何OC对象，但不能放入基本数据类型、结构体、枚举等非OC对象

不能存储nil

 

A.常用方法1

1. 创建
2. 返回用量
3. 是否含有某元素
4. 最后的元素
5. 取得某位置的元素

当一个对象放入数组的时候，这个对象的计数器加1

#pragma mark create a array
void arrayCreate()
{
    //Create an empty array
    NSArray *array = [NSArray array];
   
    //Create an array with one element
    array = [NSArray arrayWithObject:@"123"];
   
    array = [NSArray arrayWithObjects:@"a", @"b", @"d", nil];
   
    NSUInteger count =[array count];
    NSLog(@"%@", count);
   
    [array release];
}

最后的nil用作标示数组的结束，不会被存储进数组元素，不允许在其他地方插入

error:    array = [NSArray arrayWithObjects:@"a”, nil, @"d"];

#pragma mark common use
void arrayUser()
{
    NSArray *array = [NSArray arrayWithObjects:@"a", @"b", @"c", nil];
    if ([array containsObject:@"a"])
    {
        NSLog(@"Contans a");
    }
   
    NSString *last = [array lastObject];
    NSLog(@"%@", last);
   
    NSString *str = [array objectAtIndex:1];
    NSLog(@"%@", str);
   
    NSUInteger location = [array indexOfObject:@"c"];
    NSLog(@"%@", location);
   
    [array release];
}

#pragma memory manage
void memoryManage()
{
    Student *stu1 = [[Student alloc] init];
    Student *stu2 = [[Student alloc] init];
    Student *stu3 = [[Student alloc] init];
   
    NSLog(@"stu1: %zi", [stu1 retainCount]);
   
    NSArray *array = [[NSArray alloc] initWithObjects:stu1, stu2, stu3, nil];
   
    NSLog(@"stu1: %zi", [stu1 retainCount]);
   
    [stu1 release];
    [stu2 release];
    [stu3 release];
   
    [array release];
   
}

 

B.常用方法2

 

1.给数组所有元素发送消息，调用同一个方法

void arrayMessage()
{
    Student *stu1 = [[Student alloc] init];
    Student *stu2 = [[Student alloc] init];
    Student *stu3 = [[Student alloc] init];
   
    NSArray *array = [[NSArray alloc] initWithObjects:stu1, stu2, stu3, nil];
   
    [array makeObjectsPerformSelector:@selector(test2:) withObject:@"test2"];
   
    [stu1 release];
    [stu2 release];
    [stu3 release];
   
    [array release];
} 

 

2.遍历

(1)for 循坏

void arrayLoop()
{
    Student *stu = [[Student alloc]init];
    NSArray *array = [[NSArray alloc] initWithObjects:stu, @"2", @"3", nil];
    unsigned long count = array.count;
//    for (int i=0; i<count; i++)
//    {
//        id obj = [array objectAtIndex:i];
//        NSLog(@"%i - %@", i, obj);
//    }
   
    int i = 0;
    for (id obj in array)
    {
        NSLog(@"%i - %@", i, obj);
        i++;
    }
   
    [stu release];
    [array release];
}

 

（2）使用Block进行循环处理

void arrayLoopByBlock()
{
    Student *stu = [[Student alloc]init];
    NSArray *array = [[NSArray alloc] initWithObjects:stu, @"2", @"3", nil];
   
   
    [array enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        NSLog(@"%zi - %@", idx, obj);
        if (idx == 1)
        {
            *stop = YES;
        }
    }];
   
    [stu release];
    [array release];
}

 

(3).迭代器

void arrayLoopByEnumerator()
{
    Student *stu = [[Student alloc]init];
    NSArray *array = [[NSArray alloc] initWithObjects:stu, @"2", @"3", nil];
   
//    NSEnumerator *e = [array objectEnumerator];
    NSEnumerator *e = [array reverseObjectEnumerator];
    id obj = nil;
    while (obj = [e nextObject])
    {
        NSLog(@"The element is %@", obj);
    }
   
    [stu release];
    [array release];
}

创建整数数组

(1)
    

     NSArray *array61 = [NSArray arrayWithObjects:@0, @1, @2, @3, @4, @5, @6, @7, @8, @9, nil];

实际上是把数字自动转化成了NSNumber类型

 

 

(2)不能用于NSMutableArray

        

NSArray *array61 = @[@0, @1, @2, @3, @4, @5, @6, @7, @8, @9];