OC中常用排序方法

**:

①.oc中常用排序方法:

1).不可變陣列

- (nsarray *)sortedarrayusingselector:(sel)comparator;

- (nsarray *)sortedarrayusingcomparator:(nscomparator)cmptr;

- (void)sortusingselector:(sel)comparator;

- (void)sortusingcomparator:(nscomparator)cmptr;

- (nsarray *)keyssortedbyvalueusingcomparator:(nscomparator)cmptr 

- (nsarray *)keyssortedbyvalueusingselector:(sel)comparator;

1).不可變陣列排序:(方法1)

nsarray *arr = @[@"aa",@"rr",@"pp",@"hh",@"xx",@"vv"];

//用系統的方法進行排序,系統缺少兩個元素比較的方法.
//selector方法選擇器. 
nsarray *sortarr = [arr sortedarrayusingselector:@selector(compare:)];
nslog(@"%@",sortarr);

[arr sortedarrayusingcomparator:^nscomparisonresult(id obj1, id obj2) ];

nslog(@"%@",arr);
}

nsmutablearray *arr = [@[@54 ,@33,@12,@23,@65] mutablecopy];

[arr sortusingselector:@selector(compare:)];//compare陣列中兩個元素比較的方法
nslog(@"%@",arr);

[arr sortusingcomparator:^nscomparisonresult(id obj1, id obj2) ];

nslog(@"%@",arr);
}

③.例題:定義乙個學生物件,對學生物件按照,姓名,年齡,成績,學號進行排序,(兩種排序方式)

方法1:(用selector方法選擇器,需要重新定義comparator)

**如下:

1.物件宣告(student.h中)

@property (nonatomic, retain) nsstring *name;

@property (nonatomic, assign) nsinteger age;
@property (nonatomic, assign) cgfloat score;
@property (nonatomic, assign) nsinteger number;
//初始化
- (id)initwithname:(nsstring *)name age:(nsinteger)age score:
(cgfloat)score number:(nsinteger)number;
//便利構造器
+ (id)studentwithname:(nsstring *)name age:(nsinteger)age score:
(cgfloat)score number:(nsinteger)number;
//兩個學生按照年齡比較的方法
- (nscomparisonresult)comparebyage:(student *)stu;
//兩個學生按照姓名比較的方法
- (nscomparisonresult)comparebyname:(student *)stu;
//兩個學生按照成績比較的方法
- (nscomparisonresult)comparebyscore:(student *)stu;
//兩個學生按照學號比較的方法
- (nscomparisonresult)comparebynumber:(student *)stu;

- (id)initwithname:(nsstring *)name age:(nsinteger)age score:

(cgfloat)score number:(nsinteger)number 
return self;
}//便利構造器
+ (id)studentwithname:(nsstring *)name age:(nsinteger)age score:
(cgfloat)score number:(nsinteger)number 
//重寫description
- (nsstring *)description 
//兩個學生按照年齡比較的方法
- (nscomparisonresult)comparebyage:(student *)stu 
//兩個學生按照姓名降序的方法
- (nscomparisonresult)comparebyname:(student *)stu 
//兩個學生按照成績降序比較的方法
- (nscomparisonresult)comparebyscore:(student *)stu 
//兩個學生按照學號公升序的方法
- (nscomparisonresult)comparebynumber:(student *)stu

主函式(main.h)

student *student1 = [student studentwithname:@"a" age:23 score:21 number:3434343];

student *student2 = [student studentwithname:@"b" age:45 score:432.4 number:324];
student *student3 = [student studentwithname:@"c" age:32 score:4321.4 number:2343];
student *student4 = [student studentwithname:@"d" age:7 score:43.4 number:233];
student *student5 = [student studentwithname:@"e" age:73 score:65 number:2332424];
nsmutablearray *arr = [nsmutablearray arraywithobjects:
student1,student2,student3,student4,student5,nil];
//按照年齡公升序排序
[arr sortusingselector:@selector(comparebyage:)];
nslog(@"%@",arr);
//按照成績降序排序
[arr sortusingselector:@selector(comparebyscore:)];
nslog(@"%@",arr);
//按照姓名降序排序
[arr sortusingselector:@selector(comparebyname:)];
nslog(@"%@",arr);
//按照學號公升序排序
[arr sortusingselector:@selector(comparebynumber:)];
nslog(@"%@",arr);

.用block塊語法進行排序

//按年齡公升序排序

[arr sortusingcomparator:^(id obj1,id obj2) ];
nslog(@"%@",arr);
//按成績降序排序
[arr sortusingcomparator:^(id obj1,id obj2) ];
nslog(@"%@",arr);
//按姓名降序排序
[arr sortusingcomparator:^(id obj1,id obj2) ];
nslog(@"%@",arr);
//按學號公升序排序
nscomparator sortblock = ^(id obj1,id obj2) ;
[arr sortusingcomparator:sortblock];
nslog(@"%@",arr);

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