iOS 数组使用 valueForKeyPath：计算求和、平均值、最大、最小

NSArray *testArray = [NSArray arrayWithObjects:@"2.0", @"2.3", @"3.0", @"4.0", nil];2 3NSNumber *sum = [testArray valueForKeyPath:@"@sum.floatValue"];4 5NSNumber *avg = [testArray valueForKeyPath:@"@avg.floatValue"];6 7NSNumber *avg = [testArray valueForKeyPath:@"@max.floatValue"];8 9NSNumber *avg = [testArray valueForKeyPath:@"@min.floatValue"];

如果是数据模型对象：比如数据模型对象有一个属性 finishRate

CGFloat max = [[[self datas] valueForKeyPath:@"@max.finishRate"] floatValue];