如何使用汇总避免平均值（价格）的自动舍入？ 我想得到像Results1一样的结果。
> data(diamonds, package="ggplot2")
> head(diamonds)
# A tibble: 6 x 10
carat cut color clarity depth table price x y z
<dbl> <ord> <ord> <ord> <dbl> <dbl> <int> <dbl> <dbl> <dbl>
1 0.230 Ideal E SI2 61.5 55. 326 3.95 3.98 2.43
2 0.210 Premium E SI1 59.8 61. 326 3.89 3.84 2.31
3 0.230 Good E VS1 56.9 65. 327 4.05 4.07 2.31
4 0.290 Premium I VS2 62.4 58. 334 4.20 4.23 2.63
5 0.310 Good J SI2 63.3 58. 335 4.34 4.35 2.75
6 0.240 Very Good J VVS2 62.8 57. 336 3.94 3.96 2.48
结果1：
> aggregate(price~cut, diamonds, mean, na.rm=TRUE)
cut price
1 Fair 4358.758
2 Good 3928.864
3 Very Good 3981.760
4 Premium 4584.258
5 Ideal 3457.542
结果2：
> (diamonds %>% group_by(cut) %>% summarize(AvgPrice = mean(price)))
# A tibble: 5 x 2
cut AvgPrice
<ord> <dbl>
1 Fair 4359.
2 Good 3929.
3 Very Good 3982.
4 Premium 4584.
5 Ideal 3458.