首页 > 代码库 > 关于NSArray的几种排序:
关于NSArray的几种排序:
#利用数组的sortedArrayUsingComparator调用 NSComparator
其中NSComparator其实就是一个返回NSComparisonResult的block。
typedef NSComparisonResult (^NSComparator)(id obj1,id obj2); 其中obj1、obj2其实是NSArray中的元素
resultArray = [arrayDic <span style="color:#009900;">sortedArrayUsingComparator:</span>^NSComparisonResult(id obj1, id obj2) { NSNumber * number1 = [[obj1 allKeys] objectAtIndex:0]; NSNumber * number2 = [[obj2 allKeys] objectAtIndex:0]; NSComparisonResult result = [number1 compare:number2]; return result == NSOrderedAscending; }];
#利用数组的sortedArrayUsingFunction 调用 对应方法customSort
NSInteger <span style="color:#ff9900;">sortByID</span>(id obj1, id obj2, void *context){ NSString *str1 =(NSString*) obj1; // ibj1 和 obj2 来自与你的数组中,其实,个人觉得是苹果自己实现了一个冒泡排序给大家使用 NSString *str2 =(NSString *) obj2; if (str1.length < str2.length) { <span style="white-space:pre"> </span>return NSOrderedDescending; } else if(str1.length == str2.length) { <span style="white-space:pre"> </span>return NSOrderedSame; } <span style="white-space:pre"> </span>return NSOrderedAscending; }
NSArray *sortedArray =[arr sortedArrayUsingFunction:sortByID context:nil];
#利用数组的sortedArrayUsingSelector调用 对应的SEL的方法
注意selector的方法是对数组元素而言的方法,假如数据元素没有compare:方法,可以通过扩展数组元素的类增加相应的方法。
NSMutableArray *arrayDic = [NSMutableArray arrayWithObjects: [NSDictionary dictionaryWithObjectsAndKeys:@"Obj0", [NSNumber numberWithInt:0], nil], [NSDictionary dictionaryWithObjectsAndKeys:@"Obj5", [NSNumber numberWithInt:5], nil], [NSDictionary dictionaryWithObjectsAndKeys:@"Obj2", [NSNumber numberWithInt:2], nil], [NSDictionary dictionaryWithObjectsAndKeys:@"Obj3", [NSNumber numberWithInt:3], nil], [NSDictionary dictionaryWithObjectsAndKeys:@"Obj1", [NSNumber numberWithInt:1], nil], [NSDictionary dictionaryWithObjectsAndKeys:@"Obj4", [NSNumber numberWithInt:4], nil], nil]; #ifdef sortedArrayUsingSelector resultArray = [arrayDic sortedArrayUsingSelector:@selector(compare:)];
因为数组中元素对应的是字典,所以对字典的类进行扩展
@implementation NSDictionary (extend) - (NSComparisonResult)compare: (NSDictionary *)otherDictionary { NSNumber *number2 = [[otherDictionary allKeys] objectAtIndex:0]; NSDictionary *tempDictionary = (NSDictionary *)self; NSNumber *number1 = [[tempDictionary allKeys] objectAtIndex:0]; NSComparisonResult result = [number1 compare:number2]; // return result == NSOrderedDescending; // 升序 return result == NSOrderedAscending; // 降序 }
#利用数组的sortUsingDescriptors调用NSSortDescriptor
NSSortDescriptor 可以简单的理解为 指定对象的某属性的比较描述。
/** * 可以很方便的根据model对象中的某个属性进行排序 * sortDescriptor1 数组根据name进行升序排 * sortDescriptor2 数组根据age进行降序排 * 同时将两种sortDescriptor加入数组,是指先按照name排序,name相同的按照age排序 */ Person *person1 = [[Person alloc] init]; [person1 setName:@"ABC"]; [person1 setAge:24]; Person *person2 = [[Person alloc] init]; [person2 setName:@"ACB"]; [person2 setAge:22]; Person *person3 = [[Person alloc] init]; [person3 setName:@"ABD"]; [person3 setAge:33]; NSMutableArray *array = [NSMutableArray arrayWithObjects:person1, person2, person3, nil]; NSSortDescriptor *sortDescriptor1 = [NSSortDescriptor <span style="color:#ff0000;">sortDescriptorWithKey</span>:@"_name" ascending:YES]; NSSortDescriptor *sortDescriptor2 = [NSSortDescriptor <span style="color:#ff0000;">sortDescriptorWithKey</span>:@"_age" ascending:NO]; resultArray = [array sortedArrayUsingDescriptors:[NSArray arrayWithObjects:sortDescriptor1,sortDescriptor2,nil]]; for(NSInteger i = 0; i < [resultArray count]; i++) { NSLog(@"%@--------%d\n", [[resultArray objectAtIndex:i] name], [[resultArray objectAtIndex:i] age]); }
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