Subsetting, Matrices

Question

I am currently working with the diamonds dataset and from that, I want to return the row corresponding to the smallest, mean, and largest prices and put everything in a 10 by 4 matrix. 

library(ggplot2)

data(diamonds)

min(diamonds$price) 

mean(diamonds$price)

max(diamonds$price) # this one gives me the wrong val!

M<-matrix(1:cols, nrow = 1, ncol = cols)

colnames(M)<-c("carat","cut" , "color" , "clarity", "depth" , "table" , "price" ,  "x" , "y" ,"z")

# Here I need to add the rows corresponding to the min, mean, max to this matrix.

Answer 1

Let me tell you that sub-setting and matrices are two different things. If you check the summary(diamonds), it will give you some nice summary statistics for each column.

If you want to execute some specific functions to columns using dplyr, you can do :

library(dplyr)

diamonds %>%

  summarise(across(where(is.numeric),list(min = min, max = max, mean = mean))) %>%

  tidyr::pivot_longer(cols = everything(), 

                      names_to = c('col', '.value'), 

                      names_sep = '_') 

# A tibble: 7 x 4

#  col     min      max     mean

#  <chr> <dbl>    <dbl>    <dbl>

#1 carat   0.2     5.01    0.798

#2 depth  43      79      61.7  

#3 table  43      95      57.5  

#4 price 326   18823    3933.   

#5 x       0      10.7     5.73 

#6 y       0      58.9     5.73 

#7 z       0      31.8     3.54 

Note that I applied these functions only to numeric columns as the cut, color, clarity are factor columns.

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