iOS数组排序

一、利用NSSortDescriptor对象数组排序

NSSortDescriptor可以根据数组中对象的属性来排序,为排序数组的要排序的属性创建NSSortDescriptor对象，将所有这些对象放入一个数组中，该数组将会在后面用作参数。使用NSArray类的sortedArrayUsingDescripors:方法并将NSSortDescriptor对象数组作为参数传递过去，会返回一个排好序的数组。

• 创建Person类用于排序

  Person.h

  @interface Person : NSObject@property (nonatomic, copy) NSString *firstName;@property (nonatomic, copy) NSString *lastName;@property (nonatomic, assign) NSInteger age;-(instancetype)initWithFirstName:(NSString *)fName lastName:(NSString *)lName age:(NSInteger) age;

  Person.m

  @implementation Person-(instancetype)initWithFirstName:(NSString *)fName lastName:(NSString *)lName age:(NSInteger)age    {    self = [super init];    if (self) {        self.firstName = fName;        self.lastName = lName;        self.age = age;    }    return self;}

• 排序

  Person *p1 = [[Person alloc] initWithFirstName:@"Wenxuan" lastName:@"Huo" age:21];Person *p2 = [[Person alloc] initWithFirstName:@"MaHa" lastName:@"B" age:30];Person *p3 = [[Person alloc] initWithFirstName:@"MeKe" lastName:@"C" age:30];Person *p4 = [[Person alloc] initWithFirstName:@"MaLian" lastName:@"A" age:30];Person *p5 = [[Person alloc] initWithFirstName:@"HoHo" lastName:@"A" age:40];Person *p6 = [[Person alloc] initWithFirstName:@"Guo" lastName:@"Zhong" age:5000];// 包含所有Person的数组NSArray *peopleArray = @[p1, p2, p3, p4, p5, p6];// 为每个要排序的属性创建NSSortDescriptor对象NSSortDescriptor * sdFirstName = [NSSortDescriptor sortDescriptorWithKey:@"firstName"   ascending:YES];NSSortDescriptor * sdLastName = [NSSortDescriptor sortDescriptorWithKey:@"lastName"     ascending:YES];NSSortDescriptor * sdAge = [NSSortDescriptor sortDescriptorWithKey:@"age" ascending:YES];// 设置排序优先级，并组成数组。这里优先级最高为age，之后是lastName，最后是firstNameNSArray * sortedArray = [peopleArray sortedArrayUsingDescriptors:@[sdAge, sdLastName, sdFirstName]];// 为数组中每个元素执行方法，输出状态[sortedArray makeObjectsPerformSelector:@selector(printState)];

  makeObjectsPerformSelector1

二、利用sortedArrayUsingComparator

• 调用NSComparator

  //升序排列NSComparator cmptr = ^(id obj1,id obj2){    if([obj1 integerValue] > [obj2 integerValue]) {        return (NSComparisonResult)NSOrderedDescending;    }    if([obj1 integerValue] < [obj2 integerValue]) {        return (NSComparisonResult)NSOrderedAscending;    }    return (NSComparisonResult)NSOrderedSame;};NSArray *sortArray = [[NSArray alloc] initWithObjects:@"1",@"3",@"4",@"7",@"8",@"2",@"6",@"5",@"13",@"15",@"12",@"20",@"28",@"",nil];sortArray = [sortArray sortedArrayUsingComparator:cmptr];

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1. makeObjectsPerformSelector:@select（aMethod） 让数组中的每个元素都调用aMethod
   makeObjectsPerformSelector:@select（aMethod）withObject:oneObject 让数组中的每个元素 都调用 aMethod 并把 withObject 后边的 oneObject 对象做为参数传给方法aMethod ↩