OC字典集合遍历以及排序.docx

/数组遍历 /* 数组遍历 原理:通过for循环的循环变量用作数组元素下标来获取不同下标的元素。 循环次数就是数组元素的个数。 */ NSArray *cityArray = bj,hn,sx,sd,xg; /字典 NSDictionary *dic =NSDictionary dictionaryWithObjectsAndKeys:zhang3,name,chiF,hobby,18,age, nil; /集合 NSSet *set=NSSet setWithObjects:123,456,789,1011, nil; for (int i=0 ; icityArray count; i+) /根据下标从数组中取出对应下标 NSString * string = cityArray objectAtIndex:i; NSLog(*数组*%,string); /字典遍历 /* 字典遍历 原理:先获取字典中所有的key,存储到数组中,遍历数组依次取 出每一个key,然后根据key从字典中取出对应的value。 字典取值要通过key取出对应的value。 循环次数等于字典的元素个数。 */ NSArray *key=dic allKeys;/取出dic这个字典当中 的所有的key值(存储到数组) for (int i=0 ; ikey count; i+) /通过数组元素的下标取出对应的key NSString *keyy=key objectAtIndex:i; NSString* valuee=dic objectForKey:keyy; NSLog(key= % *字典* value = %,keyy,valuee); /集合遍历 /* 原理: 用集合的allObject属性先取到集合的所有元素存储到数组 中,再通过for循环的循环变量用作下标来取到每个元素 */ NSArray *setObject = set allObjects; for (int i=0 ; isetObject count; i+) /从集合的 allObjects(setObject数组)中获取对应的下标所对应的元素,并输出 NSLog(集合*%,setObject objectAtIndex:i); NSArray *string =xiaoM,erQ,sanP,siX,daC; NSMutableArray *temp =NSMutableArray arrayWithCapacity:0; for (int i=0 ; istring count; i+) temp addObject:string objectAtIndex:(string.count-1-i); NSLog(*倒取*%,temp); NSDictionary *ren =name:dada,sex:man,age:28; NSArray*keey =ren allKeys; for (int i=0 ; i%,sortedArray); /可变数组 array00 sortedArrayUsingSelector:selector(compare:); NSLog(%,array00); /数组排序-数组中存放自定义类对象排序- Person *per1=Person alloc initWithName:mhang3 age:99 sex:m; Person *per2=Person alloc initWithName:zhang4 age:19 sex:w; Person *per3=Person alloc initWithName:ahang5 age:223 sex:m; Person *per4=Person alloc initWithName:zhang6 age:217 sex:w; Person *per5=Person alloc initWithName:zhang7 age:20 sex:m; Person *per6=Person alloc initWithName:bhang08 age:23 sex:w; Person *per7=Person alloc initWithName:zhang9 age:10 sex:m; /生成数组对象 NSArray *perArray =per1,per2,per3,per4,per5,per6,per7; / NSSortDescriptor /生成初始化,排序描述-按照人名进行排序 NSSortDescriptor*sortWithName =NSSortDescriptor alloc initWithKey:name ascending:YES; /通过排序描述对数组进行排序,生成新的排序后的数组 NSArray *sortedWithName = perArray sortedArrayUsingDescriptors:NSArray arrayWithObjects:sortWithName, nil; NSLog(sortedWithName *%,sortedWithName); /年龄 NSSortDescriptor*sortWithAge =NSSortDescriptor alloc initWithKey:age ascending:0; NSArray*age0=perArray sortedArrayUsingDescriptors:NSArray arrayWithObjects:sortWithAge, nil; NSLog(sortedWithAge *%,age0); /可变数组 生成初始化描述 - 按照性别升序 NSSortDescriptor*sortWithSex =NSSortDescriptor alloc initWithKey:sex ascending:0; NSMutableArray *mArray =perArray mutableCopy; mArray sortUsingDescriptors:NSArray arrayWithObjects:sortWithSex, nil; NSLog(*mArray*%,mArray); /使用数组排序方法传入数组中两个元素比较的方法名 /不可变数组排序 /按照自定义排序规范(姓名) NSArray *resultWithNameArray = perArray sortedArrayUsingSelector:selector(compareByAge:); NSLog(%,resultWithNameArray); NSArray *rrr =perArray sortedArrayUsingSelector:selector(compareByName:); NSLog(rrrr*%,rrr);+(instancetype)personWithName:(NSString*)name age:(int)age sex:(NSString*)sex return Person alloc initWithName:name age:age sex:sex;/比较两个人年龄 -升序- (NSComparisonResult)compareByAge:(Person *)person/ int result= self.age person.age;/ NSLog(*%d,result);/ return result; /当条件表达式成立之后,条件结果是看我们返回值 -1代表降序 1代表升序 /返回-1告诉数组不用变 返回1意思是需要调换 if (self.ageperson.age) NSLog(1); return -1; else if (self.ageperson.age) NSLog(-1); return 1; else return 0; /降序- (NSComparisonResult)compareByName:(Person *)perso