in R programming, how to find the 7 most expensive prices for diamonds(dataset) of Ideal cut?

Question

Im doing R programming question on a dataset called Diamonds. First of all in order to install and load the dataset. Type the following command

install.packages("ggplot2")
library(ggplot2)
diamonds

Now because so many values and names, I need to find out the 7 most expensive prices for diamonds (dataset) of Ideal cut?

What i did is, I created a dataframe called diamond.ideal and inside the dataframe I put 3 columns and values from dataset diamonds. here's the code

diamond.ideal <- data.frame(diamonds$cut,diamonds$color, diamonds$price)
head(diamond.ideal) #or diamond.ideal

Here's the screenshot of the output

Finally, I need to find the 7 most expensive prices for diamonds of Ideal cut? This is my code But not sure it's right

diamond.ideal[which(diamond.ideal$diamonds.cut == "Ideal", diamond.ideal$diamonds.price == max(diamond.cut$diamonds.price))[990:997],]

[990:997] are the row numbers (I think) Here's the screenshot

I don't know if the figures are right, there are so many values on the dataset. I just want to know if that highest values are correct? or is there another way to find he 7 most expensive prices for diamonds of Ideal by using different function like table() or cut() or others?

Answer 1

There are several ways of doing this. Here's one taking your approach.

library(ggplot2)
data(diamonds)

xy <- diamonds[diamonds$cut == "Ideal", ]

> xy[order(xy$price, decreasing = TRUE), ][1:7, ]
# A tibble: 7 x 10
  carat   cut color clarity depth table price     x     y     z
  <dbl> <ord> <ord>   <ord> <dbl> <dbl> <int> <dbl> <dbl> <dbl>
1  1.51 Ideal     G      IF  61.7    55 18806  7.37  7.41  4.56
2  2.07 Ideal     G     SI2  62.5    55 18804  8.20  8.13  5.11
3  2.15 Ideal     G     SI2  62.6    54 18791  8.29  8.35  5.21
4  2.05 Ideal     G     SI1  61.9    57 18787  8.10  8.16  5.03
5  1.60 Ideal     F     VS1  62.0    56 18780  7.47  7.52  4.65
6  2.06 Ideal     I     VS2  62.2    55 18779  8.15  8.19  5.08
7  1.71 Ideal     G    VVS2  62.1    55 18768  7.66  7.63  4.75

> head(xy[order(xy$price, decreasing = TRUE), ], 7)
# A tibble: 7 x 10
  carat   cut color clarity depth table price     x     y     z
  <dbl> <ord> <ord>   <ord> <dbl> <dbl> <int> <dbl> <dbl> <dbl>
1  1.51 Ideal     G      IF  61.7    55 18806  7.37  7.41  4.56
2  2.07 Ideal     G     SI2  62.5    55 18804  8.20  8.13  5.11
3  2.15 Ideal     G     SI2  62.6    54 18791  8.29  8.35  5.21
4  2.05 Ideal     G     SI1  61.9    57 18787  8.10  8.16  5.03
5  1.60 Ideal     F     VS1  62.0    56 18780  7.47  7.52  4.65
6  2.06 Ideal     I     VS2  62.2    55 18779  8.15  8.19  5.08
7  1.71 Ideal     G    VVS2  62.1    55 18768  7.66  7.63  4.75