Trailing decimal mark is not dropped when digit group separator is not used

[andreabz]

Description

When use_seps = FALSE drop_trailing_dec_mark is ignored.

Reproducible example

gt::gt(mtcars) |> 
gt::fmt_number(columns = qsec,
                          n_sigfig = 2,
                          drop_trailing_dec_mark = TRUE,
                          use_seps = FALSE)

# same with

gt::gt(mtcars) |> 
gt::fmt_number(columns = qsec,
                          n_sigfig = 2,
                          drop_trailing_dec_mark = TRUE,
                          sep_mark = "")

Expected result

qsec column of mtcars should have been shown without the trailing dot (e.g. 16 17 19 and so on, instead of 16. 17. 19. and so on).

Session info

R version 4.3.3 (2024-02-29 ucrt)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 11 x64 (build 22631)

Matrix products: default

locale:
[1] LC_COLLATE=Italian_Italy.utf8 LC_CTYPE=Italian_Italy.utf8 LC_MONETARY=Italian_Italy.utf8 LC_NUMERIC=C
[5] LC_TIME=Italian_Italy.utf8

time zone: Europe/Rome
tzcode source: internal

attached base packages:
[1] stats graphics grDevices utils datasets methods base

loaded via a namespace (and not attached):
[1] digest_0.6.37 R6_2.5.1 fastmap_1.2.0 tidyselect_1.2.1 magrittr_2.0.3 glue_1.8.0 tibble_3.2.1 pkgconfig_2.0.3
[9] gt_0.11.1 htmltools_0.5.8.1 dplyr_1.1.4 generics_0.1.3 lifecycle_1.0.4 xml2_1.3.6 cli_3.6.3 sass_0.4.9
[17] vctrs_0.6.5 withr_3.0.2 pkgload_1.4.0 compiler_4.3.3 rstudioapi_0.17.1 tools_4.3.3 pillar_1.10.1 rlang_1.1.5

[olivroy]

Thanks for the report. It seems strange indeed!

Here is a more minimal reprex.

# works (has seps, and drops trailing dec mark)
vec_fmt_number(c(
  1335.31
), n_sigfig = 4, drop_trailing_dec_mark = T, use_seps = T
)
#>1,335
# doesn't work (no sep, but trailing dec mark)
vec_fmt_number(c(
  1335.31
), n_sigfig = 4, drop_trailing_dec_mark = T, use_seps = F
)
#> 1335.

This is a matter of formatC() doing different things.

here is the isolated code in format_num_to_str()

gt/R/fmt.R

Lines 591 to 601 in 37a25ab

	x_str <-
	formatC(
	x = x,
	format = format,
	mode = mode,
	digits = digits,
	flag = flag,
	drop0trailing = drop0trailing,
	big.mark = sep_mark,
	decimal.mark = dec_mark
	)

Here is the call that ends up being problematic:

# when use_seps = TRUE (everything ok)

# when use_seps = FALSE
formatC(
    x = 1335,
    format = "fg",
    mode = NULL,
    digits = 4,
    flag = "#",
    drop0trailing = FALSE,
    big.mark = "",
    decimal.mark = "."
)
#> "1335."

There is some logic to force drop_trailing_zeros = TRUE

gt/R/fmt.R

Lines 565 to 572 in 37a25ab

	if (format == "fg") {
	x <- signif(x, digits = n_sigfig)
	mode <- NULL
	digits <- n_sigfig
	flag <- "#"
	drop0trailing <- FALSE

@rich-iannone I am not sure I understand the logic in the code. Do you think it should be reviewed or should a workaround like the following be added .

gt/R/fmt.R

Lines 610 to 613 in 37a25ab

	if (!drop_trailing_dec_mark) {
	x_str_no_dec <- !grepl(dec_mark, x_str, fixed = TRUE)
	x_str[x_str_no_dec] <- paste_right(x_str[x_str_no_dec], dec_mark)
	}

  if (!drop_trailing_dec_mark) {
    x_str_no_dec <- !grepl(dec_mark, x_str, fixed = TRUE)
    x_str[x_str_no_dec] <- paste_right(x_str[x_str_no_dec], dec_mark)
  } else if (nzchar(dec_mark)) {
     # drop the trailing dec mark
    x_str[endsWith(x_str, dec_mark)] <- sub(dec_mark, "", x_str[endsWith(x_str, dec_mark)], fixed = TRUE)
  }

A test would be the following

expect_equal(
  format_num_to_str(1335.3, "html",  n_sigfig = 4, sep_mark = "", dec_mark = ".", drop_trailing_dec_mark = T,format = "fg"),
  "1335"
)