Extract max and min from a list of numbers in R

Question

I have a vector of lists that roughly resembles the following tibble :

library(tidyverse)

z <- tribble(
  ~x,
  c("65", "80", "101"),
  c("70", "83", "92"),
  c("65", "55", "84"),
  c("30", "70", "101"),
  c("82", "66", "55")
)

I would like to use regex and the tidyverse to keep/extract only the max and min values. This is all I have so far:

z %>%
  mutate(x = str_extract_all(x, "(max regex) | (min regex)"))

Answer 1

If we need the same type after extraction, convert the character vector to numeric , extract the range of values and reconvert it to character while looping over the list with map

library(dplyr)
library(purrr)
z %>%
      mutate(x = map(x, ~ as.character(range(as.numeric(.x)))))

Answer 2

Ugly, but works:

library(tidyverse)

df <- tribble(
  ~x,
  c(65, 80, 101),
  c(70, 83, 92),
  c(65, 55, 84),
  c(30, 70, 101),
  c(82, 66, 55)
)

df %>% mutate(row = row_number()) %>%
  unchop(x) %>%
  group_by(row) %>%
  mutate(max = max(x),
         min = min(x)) %>%
         chop(x)
#> # A tibble: 5 x 4
#> # Groups:   row [5]
#>     row   max   min x        
#>   <int> <dbl> <dbl> <list>   
#> 1     1   101    65 <dbl [3]>
#> 2     2    92    70 <dbl [3]>
#> 3     3    84    55 <dbl [3]>
#> 4     4   101    30 <dbl [3]>
#> 5     5    82    55 <dbl [3]>

^{Created on 2020-01-10 by the reprex package (v0.3.0)}