字符串、集合补充

来源：互联网发布：linux root鉴定错误编辑：程序博客网时间：2024/05/18 00:13

1.数组与字符间转换

componentsSeparatedByString：将字符串以x分割成数组

componentsJoinedByString：将数组以x拼接为字符串

2.排序

Description：按描述条件(“一般字符对象”或对象的属性)排序.

注意可变排序方法和不可排序方法的是否有返还值.

    NSString *str = @"123-456-789-000";    NSArray *arr = [str componentsSeparatedByString:@"-"];    NSLog(@"%@",arr);    NSString *str2 = [arr componentsJoinedByString:@""];//数组转为字符串    NSLog(@"%@",str2);        NSMutableArray *arr2 = [[NSMutableArray alloc]init];    [arr2 addObject:@"1"];    [arr2 insertObject:@"3" atIndex:0];    [arr2 addObject:@"2"];    NSLog(@"%@",arr2);    //系统的compara：适合字符串，不适合对象排序    //2    NSSortDescriptor *sort1 = [NSSortDescriptor sortDescriptorWithKey:nil ascending:YES];//nil或self    [arr2 sortUsingDescriptors:[NSArray arrayWithObject:sort1]];//注意可变排序方法和不可排序方法的区别        NSLog(@"%@",arr2);    //3复杂对象的排序    Student *s1 = [[Student alloc]init];    s1.name = @"obanma";        Student *s2 = [[Student alloc]init];    s2.name = @"jobs";        Student *s3 = [[Student alloc]init];    s3.name = @"bill";        NSMutableArray *arr3 = [NSMutableArray arrayWithObjects:s1,s2,s3,nil];        NSSortDescriptor *sort2 = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES];//kvc        [arr3 sortUsingDescriptors:[NSArray arrayWithObject:sort2]];        for (Student *stu in arr3)    {        NSLog(@"stu.name = %@",stu.name);    }

Comparator：通过代码块对”对象或对象属性“排序

Student *s1 = [[Student alloc]init];    s1.name = @"obanma";    s1.age = 38;    Student *s2 = [[Student alloc]init];    s2.name = @"jobs";    s2.age = 17;    Student *s3 = [[Student alloc]init];    s3.name = @"bill";    s3.age = 25;    NSArray *array = [[NSArray alloc]initWithObjects:s1,s2,s3,nil];    // 升序排列name和age。降序的话，调换ascend和descaend位置。        NSArray *sortAge = [array sortedArrayUsingComparator:^(id obj1,id obj2)                        {                            if([obj1 age] < [obj2 age])                            {                                return (NSComparisonResult)NSOrderedAscending;//-1                            }                            else if ([obj1 age] > [obj2 age])                            {                                return (NSComparisonResult)NSOrderedDescending;                            }                                                        return (NSComparisonResult)NSOrderedSame;                        }];    for (Student *stu in sortAge)    {        NSLog(@"stu.age = %d",stu.age);//38,17,25    }        NSArray *sortArr = [array sortedArrayUsingComparator:^(id obj1,id obj2)                        {                            NSLog(@"%d",[[obj1 name] compare: [obj2 name]]);                                                        if ([[obj1 name] compare: [obj2 name]] == NSOrderedDescending)//1                            {                                return (NSComparisonResult)NSOrderedDescending;//1                            }                            else if([[obj1 name] compare: [obj2 name]] == NSOrderedAscending)                            {                                return (NSComparisonResult)NSOrderedAscending;//-1                            }                            return (NSComparisonResult)NSOrderedSame;                        }];        for (Student *stu in sortArr)    {        NSLog(@"stu.name = %@",stu.name);    }

http://blog.csdn.net/xiaoxuan415315/article/details/9198729

http://blog.csdn.net/shx_yi/article/details/8687368

0 0