过完节回来，感觉很多东西都生疏了。总结一下数组的排序。应该不会太完美，后续添加补充。
OC中的数组排序方法其实不太多，要根据不同的使用场景来使用不同的方法。Foundation框架中一般用到一下几个方法。
1.sortedArrayUsingSelector
此方法一般用于且NSNumber、NSString的基础数据数组排序，默认升序。
举个🌰
NSArray *array = @[@"1",@"2",@"23",@"123"];
NSArray *aarray = [array sortedArrayUsingSelector:@selector(compare:)];
NSLog(@"aarray = %@",aarray);
打印结果
aarray = (
1,
123,
2,
23
)
2.sortedArrayUsingComparator
这个方法操作空间就比较大了，也是重点，一般用于数组元素对象的属性比较排序，首先看一下该方法的API文档：
NSArray *aarray = [arraysortUsingComparator:^NSComparisonResult(id _Nonnull obj1, id _Nonnull obj2) {code}];
文中usingComparator后边，调取的是一个blok，返回的是枚举类型NSComparisonResult，该block决定了数组的排序方式。
两种写法：
A.不调用compare方法
举个🌰
NSMutableArray *array = [NSMutableArray arrayWithCapacity:10];
for (NSInteger i = 0; i < 4 ; i ++) {
Person *per = [[Person alloc]init];
per.age = arc4random()%10 +1;
NSLog(@"per =%ld",per.age);
[array addObject:per];
}
NSArray *aarray = [array sortedArrayUsingComparator:^NSComparisonResult(id _Nonnull obj1, id _Nonnull obj2) {
Person *per1 = obj1;
Person *per2 = obj2;
if (per1.age > per2.age) {
//降序
return NSOrderedAscending;
//升序
// return NSOrderedDescending;
}else if (per1.age < per2.age){
//升序
// return NSOrderedAscending;
//降序
return NSOrderedDescending;
}else{
return NSOrderedSame;
}
}];
for (Person *per in aarray) {
NSLog(@"== %ld",per.age);
}
打印结果：
2018-02-26 17:48:18.051843+0800 comandLine[2527:1303915] per =2
2018-02-26 17:48:18.052047+0800 comandLine[2527:1303915] per =6
2018-02-26 17:48:18.052060+0800 comandLine[2527:1303915] per =5
2018-02-26 17:48:18.052070+0800 comandLine[2527:1303915] per =5
2018-02-26 17:48:18.052126+0800 comandLine[2527:1303915] == 6
2018-02-26 17:48:18.052137+0800 comandLine[2527:1303915] == 5
2018-02-26 17:48:18.052146+0800 comandLine[2527:1303915] == 5
2018-02-26 17:48:18.052155+0800 comandLine[2527:1303915] == 2
A.调用compare方法
举个🌰
NSMutableArray *array = [NSMutableArray arrayWithCapacity:10];
for (NSInteger i = 0; i < 4 ; i ++) {
Person *per = [[Person alloc]init];
per.age = arc4random()%10 +1;
NSLog(@"per =%ld",per.age);
[array addObject:per];
}
NSArray *aarray = [array sortedArrayUsingComparator:^NSComparisonResult(id _Nonnull obj1, id _Nonnull obj2) {
Person *per1 = obj1;
Person *per2 = obj2;
//升序
return [@([per1 age]) compare:@([per2 age])];
//降序
// return -[@([per1 age]) compare:@([per2 age])];
}];
for (Person *per in aarray) {
NSLog(@"== %ld",per.age);
}
打印结果
2018-02-26 17:50:14.930696+0800 comandLine[2573:1314917] per =9
2018-02-26 17:50:14.930995+0800 comandLine[2573:1314917] per =1
2018-02-26 17:50:14.931013+0800 comandLine[2573:1314917] per =9
2018-02-26 17:50:14.931031+0800 comandLine[2573:1314917] per =10
2018-02-26 17:50:14.931149+0800 comandLine[2573:1314917] == 1
2018-02-26 17:50:14.931161+0800 comandLine[2573:1314917] == 9
2018-02-26 17:50:14.931167+0800 comandLine[2573:1314917] == 9
2018-02-26 17:50:14.931172+0800 comandLine[2573:1314917] == 10
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