iOS获取数组最大值、最小值、平均值、总和

数组的最值获取关键字：

@"@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"(总和)

1.列举一组数字数组

    NSArray *numArr = @[@"15", @"5", @"56", @"61", @"18", @"21", @"9"];

2.获取最值

    // 获取最小值
    CGFloat min = [[numArr valueForKeyPath:@"@min.floatValue"] floatValue];
    NSLog(@"min-----%.f", min);
    // 获取最大值
    CGFloat max = [[numArr valueForKeyPath:@"@max.floatValue"] floatValue];
    NSLog(@"max-----%.f", max);
    // 获取平均值
    CGFloat avg = [[numArr valueForKeyPath:@"@avg.floatValue"] floatValue];
    NSLog(@"avg-----%.f", avg);
    // 获取数组大小
    CGFloat count = [[numArr valueForKeyPath:@"@count.floatValue"] floatValue];
    NSLog(@"count-----%.f", count);
    // 总和
    CGFloat sum = [[numArr valueForKeyPath:@"@sum.floatValue"] floatValue];
    NSLog(@"sum-----%.2f", sum);
    // 获取最大值的角标
    NSInteger index = [numArr indexOfObject:[NSString stringWithFormat:@"%.f",max]];
    NSLog(@"index-----%ld", index);

3.打印结果：