NSArray排序方法讲解
给数组排序有着多种方式
最麻烦的是sortedArrayUsingSelector:,其次是sortedArrayUsingDescriptors:,最容易使用的就是sortedArrayUsingComparator:
从最容易使用的开始吧:
// 原始数组
NSArray *array = @[@"b", @"a", @"x", @"o", @"g", @"o"];
// 排序数组
NSArray *sort = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
NSString *str1 = obj1;
NSString *str2 = obj2;
return [str1 compare:str2];
}];
// 打印排序数组
[sort enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
NSLog(@"%@", obj);
}];这么一行就解决了,实在是太容易了.
要对什么对象排序就用相应的对象接收就行了:)
是不是简单过头了呢.
请记住,用block排序是最简单的方式!
下面来试试sortedArrayUsingDescriptors:这个方法.
sortedArrayUsingDescriptors:一般用来给Model进行排序,block也能对Model进行排序.先给出Model的定义(看教程不要太懒,自己敲代码吧)
以下是排序的代码:
//
// AppDelegate.m
// Sort
//
// http://www.cnblogs.com/YouXianMing/
//
// Copyright (c) 2014年 Y.X. All rights reserved.
//
#import "AppDelegate.h"
#import "Model.h"
@implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
[self sort];
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}
- (void)sort
{
// 原始数组
NSArray *array = @[[Model name:@"YouXianMing" age:@26 height:171],
[Model name:@"XiaoQiu" age:@27 height:170],
[Model name:@"HaoQuShi" age:@28 height:172],
[Model name:@"JunGang" age:@24 height:171],
[Model name:@"KongMing" age:@30 height:175],
[Model name:@"GaoFuShuai" age:@22 height:180]];
// 排序描述信息
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES];
NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
NSArray *sortedArray = [array sortedArrayUsingDescriptors:sortDescriptors];
// 打印排序信息
[sortedArray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
Model *tmp = obj;
NSLog(@"%@", tmp.name);
}];
}
@end看下图,其实呢,NSSortDescriptor只是一个获取keyPath的工具,他能根据keyPath进行排序而已,仅此而已:)
看一下打印信息:
2014-07-01 09:09:43.563 Sort[86442:60b] GaoFuShuai
2014-07-01 09:09:43.565 Sort[86442:60b] HaoQuShi
2014-07-01 09:09:43.565 Sort[86442:60b] JunGang
2014-07-01 09:09:43.566 Sort[86442:60b] KongMing
2014-07-01 09:09:43.566 Sort[86442:60b] XiaoQiu
2014-07-01 09:09:43.567 Sort[86442:60b] YouXianMing
很easy吧.
这种东西还是封装成类目比较好的样子.
使用:
//
// AppDelegate.m
// Sort
//
// http://www.cnblogs.com/YouXianMing/
//
// Copyright (c) 2014年 Y.X. All rights reserved.
//
#import "AppDelegate.h"
#import "Model.h"
#import "NSArray+YXSort.h"
@implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
[self sort];
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}
- (void)sort
{
// 原始数组
NSArray *array = @[[Model name:@"YouXianMing" age:@26 height:171],
[Model name:@"XiaoQiu" age:@27 height:170],
[Model name:@"HaoQuShi" age:@28 height:172],
[Model name:@"JunGang" age:@24 height:171],
[Model name:@"KongMing" age:@30 height:175],
[Model name:@"GaoFuShuai" age:@22 height:180]];
// 排序
NSArray *sortedArray = [array sortedWithKeyPath:@"name" ascending:YES];
// 打印排序信息
[sortedArray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
Model *tmp = obj;
NSLog(@"%@", tmp.name);
}];
}
@end一句话就能实现排序,多简单:),开发就得隐藏不必要的繁文缛节,减少不必要的干扰才是正道.
第三种方法sortedArrayUsingSelector:,也许是你最常用的方法,这个我就不讲了,我觉得太麻烦了,还得另外写一个比较的方法......
总结:
==本人倾向于这么用==
1. 优先用block排序
2. 用NSSortDescriptor的keyPath排序
3. 再不济请用sortedArrayUsingSelector:方法排序
附录:
用block对Model排序一样非常简单直白暴力,只需用Model接收对象就可以了.