Cannot flexibly combine pivot_longer value column names from .value sentinels

[shirdekel]

I'd like to combine the column names of a pivot_longer output that was set up with multiple .value sentinels in a custom way. For instance, I'd like the below to have the value column names x_A, and x_B. At the moment, it seems that the two .values just get concatenated and become xA, and xB. Maybe a glue call can be added so that I could do names_to = c(".value", "set", "_{.value}")?

library(tidyr)
library(dplyr)
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union

anscombe |>
  rename_with(
    \(x) x |>
      paste0("A"),
    .cols = starts_with("x")
  ) |>
  rename_with(
    \(x) x |>
      paste0("B"),
    .cols = starts_with("y")
  ) |>
  pivot_longer(
    everything(),
    names_to = c(".value", "set", ".value"),
    names_pattern = "(.)(.)(.)"
  )
#> # A tibble: 44 × 3
#>    set      xA    yB
#>    <chr> <dbl> <dbl>
#>  1 1        10  8.04
#>  2 2        10  9.14
#>  3 3        10  7.46
#>  4 4         8  6.58
#>  5 1         8  6.95
#>  6 2         8  8.14
#>  7 3         8  6.77
#>  8 4         8  5.76
#>  9 1        13  7.58
#> 10 2        13  8.74
#> # … with 34 more rows

^{Created on 2023-03-02 with reprex v2.0.2}

Session info

sessioninfo::session_info()
#> ─ Session info ───────────────────────────────────────────────────────────────
#>  setting  value
#>  version  R version 4.2.2 (2022-10-31)
#>  os       macOS Monterey 12.6
#>  system   aarch64, darwin20
#>  ui       X11
#>  language (EN)
#>  collate  en_AU.UTF-8
#>  ctype    en_AU.UTF-8
#>  tz       Australia/Sydney
#>  date     2023-03-02
#>  pandoc   2.19.2 @ /opt/homebrew/bin/ (via rmarkdown)
#> 
#> ─ Packages ───────────────────────────────────────────────────────────────────
#>  package     * version    date (UTC) lib source
#>  cli           3.6.0      2023-01-09 [1] CRAN (R 4.2.0)
#>  digest        0.6.31     2022-12-11 [1] CRAN (R 4.2.0)
#>  dplyr       * 1.1.0      2023-01-29 [1] CRAN (R 4.2.0)
#>  evaluate      0.20       2023-01-17 [1] CRAN (R 4.2.2)
#>  fansi         1.0.4      2023-01-22 [1] CRAN (R 4.2.0)
#>  fastmap       1.1.0      2021-01-25 [1] CRAN (R 4.2.0)
#>  fs            1.5.2      2021-12-08 [1] CRAN (R 4.2.0)
#>  generics      0.1.3      2022-07-05 [1] CRAN (R 4.2.0)
#>  glue          1.6.2      2022-02-24 [1] CRAN (R 4.2.0)
#>  highr         0.10       2022-12-22 [1] CRAN (R 4.2.0)
#>  htmltools     0.5.4      2022-12-07 [1] CRAN (R 4.2.0)
#>  knitr         1.41       2022-11-18 [1] CRAN (R 4.2.0)
#>  lifecycle     1.0.3      2022-10-07 [1] CRAN (R 4.2.0)
#>  magrittr      2.0.3      2022-03-30 [1] CRAN (R 4.2.0)
#>  pillar        1.8.1      2022-08-19 [1] CRAN (R 4.2.0)
#>  pkgconfig     2.0.3      2019-09-22 [1] CRAN (R 4.2.0)
#>  purrr         1.0.1      2023-01-10 [1] CRAN (R 4.2.0)
#>  R.cache       0.16.0     2022-07-21 [1] CRAN (R 4.2.0)
#>  R.methodsS3   1.8.2      2022-06-13 [1] CRAN (R 4.2.0)
#>  R.oo          1.25.0     2022-06-12 [1] CRAN (R 4.2.0)
#>  R.utils       2.12.2     2022-11-11 [1] CRAN (R 4.2.0)
#>  R6            2.5.1      2021-08-19 [1] CRAN (R 4.2.0)
#>  reprex        2.0.2      2022-08-17 [1] CRAN (R 4.2.0)
#>  rlang         1.0.6      2022-09-24 [1] CRAN (R 4.2.0)
#>  rmarkdown     2.19       2022-12-15 [1] CRAN (R 4.2.0)
#>  sessioninfo   1.2.2      2021-12-06 [1] CRAN (R 4.2.0)
#>  stringi       1.7.12     2023-01-11 [1] CRAN (R 4.2.0)
#>  stringr       1.5.0      2022-12-02 [1] CRAN (R 4.2.0)
#>  styler        1.9.0      2023-01-15 [1] CRAN (R 4.2.0)
#>  tibble        3.1.8      2022-07-22 [1] CRAN (R 4.2.0)
#>  tidyr       * 1.3.0.9000 2023-03-02 [1] Github (tidyverse/tidyr@0764e65)
#>  tidyselect    1.2.0      2022-10-10 [1] CRAN (R 4.2.0)
#>  utf8          1.2.3      2023-01-31 [1] CRAN (R 4.2.0)
#>  vctrs         0.5.2      2023-01-23 [1] CRAN (R 4.2.0)
#>  withr         2.5.0      2022-03-03 [1] CRAN (R 4.2.0)
#>  xfun          0.36       2022-12-21 [1] CRAN (R 4.2.0)
#>  yaml          2.3.6      2022-10-18 [1] CRAN (R 4.2.0)
#> 
#>  [1] /Library/Frameworks/R.framework/Versions/4.2-arm64/Resources/library
#> 
#> ──────────────────────────────────────────────────────────────────────────────

[hadley]

Some more minimal reprex:

library(tidyverse)

df <- tibble(
  x1a = 1,
  x2a = 2,
  y1b = 3,
  y2b = 4
)
df |>
  pivot_longer(
    everything(),
    names_to = c(".value", "set", ".value"),
    names_pattern = "(.)(.)(.)"
  )
#> # A tibble: 2 × 3
#>   set      xa    yb
#>   <chr> <dbl> <dbl>
#> 1 1         1     3
#> 2 2         2     4

^{Created on 2023-11-01 with reprex v2.0.2}

I'm actually surprised using .value twice works at all! But it would be nice to get a bit more control here; not sure how to do that with adding more complexity elsewhere. At a minimum maybe we could separate with _ so at least you have some chance of extracting.