pivot_longer versus gather

pivot_longer_example.R

library(tidyverse)
d1 <- tibble(name = c("Clay", "Laura"),
             score_1 = c(88, 99),
             score_2 = c(77, 88),
             score_3 = c(55, 66),
             survey_1 = c(4, 5),
             survey_2 = c(3, 3),
             survey_3 = c(2, 5))
d1
# A tibble: 2 x 7
#  name  score_1 score_2 score_3 survey_1 survey_2 survey_3
#  <chr>   <dbl>   <dbl>   <dbl>    <dbl>    <dbl>    <dbl>
#1 Clay       88      77      55        4        3        2
#2 Laura      99      88      66        5        3        5

# Let's say we want this.

#   name  id    score survey
# 1 Clay  1        88      4
# 2 Clay  2        77      3
# 3 Clay  3        55      2
# 4 Laura 1        99      5
# 5 Laura 2        88      3
# 6 Laura 3        66      5

# gather - takes two steps plus a join
r1 <- d1 %>% 
  select(name, starts_with("score")) %>% 
  gather(key = "id", value = "score", -name) %>% 
  mutate(id = str_extract(id, "[0-9]"))
r2 <- d1 %>% 
  select(name, starts_with("survey")) %>% 
  gather(key = "id", value = "survey", -name) %>% 
  mutate(id = str_extract(id, "[0-9]"))

d_long <- left_join(r1, r2, by = c("name", "id")) %>% 
  arrange(name, id)
d_long
# A tibble: 6 x 4
#  name  id    score survey
#  <chr> <chr> <dbl>  <dbl>
#1 Clay  1        88      4
#2 Clay  2        77      3
#3 Clay  3        55      2
#4 Laura 1        99      5
#5 Laura 2        88      3
#6 Laura 3        66      5

# pivot_longer - all-in-one, though a little abstract!!
pivot_longer(d1, 
             -name, 
             names_to = c(".value", "id"), 
             names_sep = "_")
# A tibble: 6 x 4
#  name  id    score survey
#  <chr> <chr> <dbl>  <dbl>
#1 Clay  1        88      4
#2 Clay  2        77      3
#3 Clay  3        55      2
#4 Laura 1        99      5
#5 Laura 2        88      3
#6 Laura 3        66      5