目录[-]
1、简单排序(sortedArrayUsingSelector:)2、利用block语法(sortedArrayUsingComparator:)3、高级排序(sortedArrayUsingDescriptors:)大体上,OC中常用的数组排序有以下几种方法:sortedArrayUsingSelector:;sortedArrayUsingComparator:;sortedArrayUsingDescriptors:
1、简单排序(sortedArrayUsingSelector:)
如果只是对字符串的排序,可以利用sortedArrayUsingSelector:方法就可以了,代码如下
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void
sortArray1(){
NSArray *array = [NSArray arrayWithObjects:@
"abc"
,@
"456"
,@
"123"
,@
"789"
,@
"ef"
, nil];
NSArray *sortedArray = [array sortedArrayUsingSelector:@selector(compare:)];
NSLog(@
"排序后:%@"
,sortedArray);
}
当然,除了利用字符串自带的compare:方法,也可以自己写compare:方法,进行对象的比较;如下:
首先是新建了Person类,实现方法如下(头文件就省了):
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#import "Person.h"
@implementation Person
+(Person *)personWithAge:(
int
) age withName:(NSString *)name{
Person *person = [[Person alloc] init];
person.age = age;
person.name = name;
return
person;
}
-(NSComparisonResult)comparePerson:(Person *)person{
NSComparisonResult result = [[NSNumber numberWithInt:person.age] compare:[NSNumber numberWithInt:self.age]];
if
(result == NSOrderedSame) {
result = [self.name compare:person.name];
}
return
result;
}
@end
主函数代码如下:
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void
sortArray2(){
Person *p1 = [Person personWithAge:23 withName:@
"zhangsan"
];
Person *p2 = [Person personWithAge:21 withName:@
"lisi"
];
Person *p3 = [Person personWithAge:24 withName:@
"wangwu"
];
Person *p4 = [Person personWithAge:24 withName:@
"liwu"
];
Person *p5 = [Person personWithAge:20 withName:@
"liwu"
];
NSArray *array = [NSArray arrayWithObjects:p1,p2,p3,p4,p5, nil];
NSArray *sortedArray = [array sortedArrayUsingSelector:@selector(comparePerson:)];
NSLog(@
"排序后:%@"
,sortedArray);
}
2、利用block语法(sortedArrayUsingComparator:)
苹果官方提供了block语法,比较方便。其中数组排序可以用sortedArrayUsingComparator:方法,代码如下:
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void
sortArray3(){
NSArray *array = [NSArray arrayWithObjects:@
"1bc"
,@
"4b6"
,@
"123"
,@
"789"
,@
"3ef"
, nil];
NSArray *sortedArray = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
NSComparisonResult result = [obj1 compare:obj2];
return
result;
}];
NSLog(@
"排序后:%@"
,sortedArray);
}
3、高级排序(sortedArrayUsingDescriptors:)
如果是这样一种情况呢?Person类里有另外一个类的变量,比如说Person类除了name,age变量,还有一辆车Car类型,Car类里有个name属性。对Person对象进行排序,有这样的要求:按照Car的name排序,如果是同一辆车,也就是Car的name相同,那么再按照年龄进行排序,如果年龄也相同,最后按照Person的name进行排序。
上面这样就要使用第三种方法,利用排序描述器,不多说,有兴趣可以看看API介绍。代码如下:
首先写个Car类,实现类Car.m代码如下:
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#import "Car.h"
@implementation Car
+(Car *)initWithName:(NSString *)name{
Car *car = [Car alloc] init];
car.name = name;
return
car;
}
@end
然后改写Person类,实现类Person.m代码如下:
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#import "Person.h"
#import "Car.h"
@implementation Person
+(Person *)personWithAge:(
int
)age withName:(NSString *)name withCar:(Car *)car{
Person *person = [[Person alloc] init];
person.age = age;
person.name = name;
person.car = car;
return
person;
}
-(NSString *)description{
return
[NSString stringWithFormat:@
"age is %zi , name is %@, car is %@"
,_age,_name,_car.name];
}
@end
主函数代码如下:
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void
sortArray4(){
Car *car1 = [Car initWithName:@
"Audio"
];
Car *car2 = [Car initWithName:@
"Rolls-Royce"
];
Car *car3 = [Car initWithName:@
"BMW"
];
Person *p1 = [Person personWithAge:23 withName:@
"zhangsan"
withCar:car2];
Person *p2 = [Person personWithAge:21 withName:@
"zhangsan"
withCar:car1];
Person *p3 = [Person personWithAge:24 withName:@
"lisi"
withCar:car1];
Person *p4 = [Person personWithAge:23 withName:@
"wangwu"
withCar:car3];
Person *p5 = [Person personWithAge:23 withName:@
"wangwu"
withCar:car2];
NSArray *array = [NSArray arrayWithObjects:p1,p2,p3,p4,p5, nil];
NSSortDescriptor *carNameDesc = [NSSortDescriptor sortDescriptorWithKey:@
"car.name"
ascending:YES];
NSSortDescriptor *personNameDesc = [NSSortDescriptor sortDescriptorWithKey:@
"name"
ascending:YES];
NSSortDescriptor *personAgeDesc = [NSSortDescriptor sortDescriptorWithKey:@
"age"
ascending:YES];
NSArray *descriptorArray = [NSArray arrayWithObjects:personAgeDesc,carNameDesc,personNameDesc, nil];
NSArray *sortedArray = [array sortedArrayUsingDescriptors: descriptorArray];
NSLog(@
"%@"
,sortedArray);
}
结果如下:
从结果看出,先按照age排序,如果age相同,按照car排序,如果car相同,按照name排序。
(注意:上面两种排序方法要想实现字符串显示,请重写description方法)