Using tidyverse nesting to unpack a vector of results into a long-format tibble

nesting-example.R

library(tidyverse)

# values at which to evaluate
# this can be changed arbitrarily
x <- c(1,2,3) 

# evaluate y's for every condition and output a long format table
df <- expand.grid(coef=c(1,2), pow=c(1,2,3)) %>%
  group_by(coef, pow) %>%
  mutate(y=map2(coef, pow, ~ tibble(x=x, y=.x*x^.y))) %>%
  unnest()
  
df
## A tibble: 18 x 4
## Groups:   coef, pow [6]
#    coef   pow     x     y
#   <dbl> <dbl> <dbl> <dbl>
# 1     1     1     1     1
# 2     1     1     2     2
# 3     1     1     3     3
# 4     2     1     1     2
# 5     2     1     2     4
# 6     2     1     3     6
# 7     1     2     1     1
# 8     1     2     2     4
# 9     1     2     3     9
#10     2     2     1     2
#11     2     2     2     8
#12     2     2     3    18
#13     1     3     1     1
#14     1     3     2     8
#15     1     3     3    27
#16     2     3     1     2
#17     2     3     2    16
#18     2     3     3    54