数组和集合——NSArray/NSSet

数组

NSArray 初始化方法

NSArray *array = [[NSArray alloc] init];NSArray *array1 = @[@"x",@"as",@"da"];//对象方法NSArray *array2 = [[NSArray alloc] initWithObjects:@"a", @"b", @"c", nil];//类方法NSArray *array5 = [NSArray arrayWithObjects:@"d", @"j", @"151", nil];NSArray *array3 = [[NSArray alloc] initWithArray:array1];

获取数组中的对象

NSLog(@"%@", [array1 objectAtIndex:2]);NSLog(@"%@", array1[2]);

获取数组的长度（元素的个数）

NSLog(@"%ld", array1.count);

查询某个对象的下标

//查找对象下标NSLog(@"%ld", [array1 indexOfObject:@"as"]);

NSMutableArray

NSMutableArray *mutableArray = [NSMutableArray array];

添加元素

NSString *name = @"dasd";[mutableArray addObject:name];//从一个数组添加（添加内容为数组全部内容）[mutableArray addObjectsFromArray:array2];

插入元素

[mutableArray insertObject:@"15" atIndex:3];

删除元素

//删除某一个元素[mutableArray removeObject:@"15"];NSLog(@"%@", mutableArray);//删除所有元素//[mutableArray removeAllObjects];//删除数组最后的元素[mutableArray removeLastObject];

替换元素

[mutableArray replaceObjectAtIndex:1 withObject:@"ada"];//交换指定位置的两个元素[mutableArray exchangeObjectAtIndex:0 withObjectAtIndex:1];NSLog(@"%@", mutableArray);

数组排序

NSLog(@"%@", [array1 sortedArrayUsingSelector:@selector(caseInsensitiveCompare:)]);

示例：图书管理

    NSMutableArray *bookArray = [NSMutableArray array];    Book *a = [[Book alloc] initWithBookName:@"a" withBookMoney:15];    Book *b = [[Book alloc] initWithBookName:@"b" withBookMoney:35];    Book *c = [[Book alloc] initWithBookName:@"c" withBookMoney:50];    //添加书籍    [bookArray addObject:a];    [bookArray addObject:b];    [bookArray addObject:c];    //删除书籍    [bookArray removeObject:b];//    展示所有书籍的清单    for (Book *book in bookArray) {        [book printBook];    }    //可以从数组根据书名查找书籍,并修改书籍的价格    NSString *string = @"c";    for (Book *book in bookArray) {        if ([book.bookName isEqualToString:string]) {            book.bookMoney = 100;            [book printBook];        }    }

数值对象

初始化

NSNumber *number = [NSNumber numberWithInteger:10];NSNumber *number2 = [NSNumber numberWithInt:12];

转换

NSInteger index = number.integerValue;    int asss = number2.intValue;

集合

NSSet（集合是无序的，所以不能按存储顺序取元素）
创建集合对象

NSSet *set = [[NSSet alloc] initWithObjects:@"a", @"c", @"2", nil];//根据数组初始化NSSet *set1 = [NSSet setWithArray:array1];

获取元素个数

NSLog(@"%ld", [set count]);//获取集合中的某一个元素NSLog(@"%@", [set1 anyObject]);

判断集合中是否包含某一个对象

if ([set containsObject:@"c"]) {    NSLog(@"存在");}

NSMutableSet

NSMutableSet *mutableSet = [NSMutableSet setWithObjects:@"a", @"s", @"d", nil];

添加元素

[mutableSet addObject:@"f"];

删除元素

[mutableSet removeObject:@"a"];    NSLog(@"%@", mutableSet);