NSArray/NSMutablearray

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//oc中用的数组里面的元素都是对象.不放基本数据类型(标量).
    //定义数组
    NSArray *arr1 = [[NSArray alloc]initWithObjects:@"1",@"2",@"3", nil];
    NSLog(@"%@",arr1);

    //便利构造器
    NSArray *arr2 = [NSArray arrayWithObjects:@"4",@"5",@"6", nil];
    NSLog(@"%@",arr2);

    //利用数组初始化数组
    NSArray *arr3 = [NSArray arrayWithArray:arr2];
    NSLog(@"%@",arr3);

    //字面量方法赋初值,语法糖
    NSArray *arr4 = @[@"1",@"2",@"3"];

NSLog(@"%@",arr4);

//利用下标快捷取出数组元素

NSMuTableArray[下标];

    //计算数组里的元素的个数
    NSUInteger ui1 = [arr4 count];
    NSLog(@"%lu",ui1);

    //取出元素相对应的下标的方法
    NSUInteger ui2 = [arr4 indexOfObject:@"3"];
    NSLog(@"%lu",ui2);

    //根据下标取出相对应的元素
    NSLog(@"%@",[arr4 objectAtIndex:2]);



    //----定义
    NSMutableArray *marr1 = [NSMutableArray arrayWithObjects:@"1",@"2",@"3", nil];

    //添加元素,默认在数组最后面开始添加
    [marr1 addObject:@"a"];
    [marr1 addObject:@"b"];
    NSLog(@"%@",marr1);

    //删除元素
    [marr1 removeLastObject];
    NSLog(@"%@",marr1);
    [marr1 removeObject:@"a"];
    NSLog(@"%@",marr1);
    [marr1 removeObjectAtIndex:0];
    NSLog(@"%@",marr1);

    //插入元素
    [marr1 insertObject:@"1" atIndex:0];
    NSLog(@"%@",marr1);

    //替换元素
    [marr1 replaceObjectAtIndex:0 withObject:@"a"];
    NSLog(@"%@",marr1);
    [marr1 replaceObjectAtIndex:2 withObject:@"c"];

NSLog(@"%@",marr1);

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