oc随笔五：NSArray

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        //NSArray的初始化以及常用数组操作方法简单归纳
        //不可变数组
        //数组的元素只能是对象，如果是int和float的话，就用NSNumber转换一下才能用
        //初始化的几种方式，可以一个元素、多个元素、从已有组复制、从文件、网址等
        NSArray *arr1 = [NSArray arrayWithObject:@"hello"];
        for (id a in arr1) {
            NSLog(@"%@",a);
        }
        //向数组对象初始化赋值，这里可以写任意对象的指针，结尾必须使用nil
        NSArray *arr2 = [NSArray arrayWithObjects:@"hello",@"world", nil];
        for (id b in arr2) {
            NSLog(@"%@",b);
        }
        //定义指定类型的数组
        NSString *str[3];
        NSNumber *num[3];
        //初始化数组元素赋值
        str[0] = @"hello";
        str[1] = @"world";
        str[2] = @"!";
        num[0] = [[NSNumber alloc] initWithInt:1];
        num[1] = [[NSNumber alloc] initWithInt:2];
        num[2] = [[NSNumber alloc] initWithInt:3];
        NSArray *arr3 = [NSArray arrayWithObjects:str count:3];
        NSArray *arr4 = [NSArray arrayWithObjects:num count:3];
        //遍历数组方法一
        for (id strr in arr3) {
            NSLog(@"%@",strr);
        }
        //遍历数组方法二
        for (int i = 0; i < [arr4 count]; i++) {
            NSLog(@"%@",[arr4 objectAtIndex:i]);
        }
        //复制数组
        NSArray *arr5 = [NSArray arrayWithArray:arr4];
        for (NSNumber *c in arr5) {
            NSLog(@"%@",c);
        }
        //给数组增加新元素(对象)
        NSArray *newArr5 = [arr5 arrayByAddingObject:@"Augus"];
        for (int i = 0 ; i < [newArr5 count]; i++) {
            if (i == [newArr5 count] - 1) {
                NSLog(@"%@",[newArr5 objectAtIndex:i]);
            }
        }
        //把数组里元素利用连接符连接成字符串
        NSString *strNew = [arr5 componentsJoinedByString:@"-"];
        NSLog(@"%@",strNew);
        //查询数组中是否包含某一元素，YES和NO
        BOOL isContain = [arr3 containsObject:@"hello"];
        NSLog(@"%d",isContain);
        //查询并返回位置，如没有则为NSNotFound
        NSInteger index = [arr3 indexOfObject:@"!"];
        NSString *indexF = [NSString stringWithFormat:@"%ld",index];
        NSInteger indexN = [indexF integerValue];//类型转换
        NSLog(@"%ld",indexN);
        //获取最后一个元素
        NSString *lastEle = [arr3 lastObject];
        NSLog(@"%@",lastEle);
        //可变数组，5个元素
        NSMutableArray *mutArr = [[NSMutableArray alloc] initWithCapacity:5];
        //添加一个元素
        [mutArr addObject:@"hello"];
        [mutArr addObject:[NSNumber numberWithInt:66]];
        [mutArr addObject:@"Augus"];
        [mutArr addObject:[NSNumber numberWithDouble:19.9]];
        //指定位置插入一个元素
        [mutArr insertObject:@"world" atIndex:1];
        //移除数组的元素，按名称、按序号等
        NSLog(@"%@",mutArr);
        [mutArr removeLastObject];
        NSLog(@"%@",mutArr);
        //替换元素
        [mutArr replaceObjectAtIndex:2 withObject:@"!"];
        NSLog(@"%@",mutArr);
        //把一个数组添加到另一个里,实际上就是把数组里的元素都添加进去了
        [mutArr addObjectsFromArray:arr4];
        NSLog(@"%@",mutArr);
        NSLog(@"%ld",[mutArr count]);
    }
    return 0;
}