现有如下数组：
NSArray *vals1 = @[@"1",@"3",@"5",@"8",@"8",@"8",@"8",@"8"];
NSArray *vals2 = @[@"2",@"4",@"6",@"8",@"6",@"6",@"6",@"6"];
1、通过valueForKeyPath方法
NSMutableArray *mutale = [[NSMutableArray alloc] init];
[mutale addObjectsFromArray:vals1];
[mutale addObjectsFromArray:vals2];
CGFloat maxValue = [[mutale valueForKeyPath:@"@max.floatValue"] floatValue];
@"@max.floatValue"（获取最大值），
@"@min.floatValue"（获取最小值），
@"@avg.floatValue" (获取平均值)，
@"@count.floatValue"(获取数组大小)
@"@sum.floatValue"(数组的总和)
2、比较
NSMutableArray *mutale = [[NSMutableArray alloc] init];
[mutale addObjectsFromArray:vals1];
[mutale addObjectsFromArray:vals2];
NSSet *set = [NSSet setWithArray:mutale];
NSArray *arrary = [set allObjects];
NSInteger max = -100000000;
NSInteger min = 1000000000;
for (NSString *valueString in arrary) {
NSInteger value = [valueString integerValue];
if (value > max) {
max = value;
}
if (value < min) {
min = value;
}
}
如果数组中有大量的重复值，我通过NSSet进行了一步过滤。
上面也可通过排序算法得到最大最小值
3、冒泡排序
NSMutableArray *mutale = [[NSMutableArray alloc] init];
[mutale addObjectsFromArray:vals1];
[mutale addObjectsFromArray:vals2];
for (int i =0; i<[mutale count]-1; i++) {
for (int j =0; j<[mutale count]-1-i; j++) {
// if(([mutale[j] compare:mutale[j+1]]) == NSOrderedDescending)
if([muti[j] integerValue] < [muti[j+1] integerValue] )
{
//交换
[mutale exchangeObjectAtIndex:j withObjectAtIndex:j+1];
}
}
}
4、选择排序
NSMutableArray *mutale = [[NSMutableArray alloc] init];
[mutale addObjectsFromArray:vals1];
[mutale addObjectsFromArray:vals2];
for (int i =0; i<[mutale count]-1; i++) {
for (int j = i+1; j<[mutale count]; j++) {
if ([mutale[i] intValue]>[mutale[j] intValue]) {
//交换
[mutale exchangeObjectAtIndex:i withObjectAtIndex:j];
}
}
}
5、升序降序
NSMutableArray *mutale = [[NSMutableArray alloc] init];
[mutale addObjectsFromArray:vals1];
[mutale addObjectsFromArray:vals2];
NSSet *set = [NSSet setWithArray:mutale];
NSArray *arrary = [set allObjects];
//对数组进行排序
NSArray *result = [arrary sortedArrayUsingComparator:^NSComparisonResult(id _Nonnull obj1, id _Nonnull obj2) {
return[obj1 compare:obj2 options:NSNumericSearch];//数字在前，字母在后，排序
// return [obj1 compare:obj2]; //升序
// return [obj2 compare:obj1]; //降序
}];
注意：经过实践，return [obj1 compare:obj2];或者return [obj2 compare:obj1];比如@[@"6",@"8",@"7",@"9",@"10"];这样的数组，升序降序都无法正常进行排序。慎用！这方法对于时间的排序还是很好用的。但是对于@[@"2017.2",@"2017.5",@"2017.11"];也无法正常排序
另外，以下方法也无法进行正常排序。
NSArray *result = [arrary sortedArrayUsingComparator:^NSComparisonResult(id _Nonnull obj1, id _Nonnull obj2) {
if ([obj1 intValue] > [obj2 intValue]){
return NSOrderedAscending;
}
if ([obj1 intValue] < [obj2 intValue]){
return NSOrderedAscending;
}
return NSOrderedSame;
}];
NSArray *result = [arrary sortedArrayUsingSelector:@selector(compare:)];
下面是创建选择器，进行排序。对于上面方法的补充。
NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:@"self"
ascending:NO];
NSArray *descriptors = [NSArray arrayWithObject:descriptor];
NSArray *reverseOrder = [setArr sortedArrayUsingDescriptors:descriptors];
