fix #1933: when col.names in kable() has more elements than the numbe…

…r of columns when row names is treated as a column, use the last N elements (N = ncol(data)); this means the column name of row names can be specified as the first element in col.names now

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: knitr
 Type: Package
 Title: A General-Purpose Package for Dynamic Report Generation in R
-Version: 1.43.13
+Version: 1.43.14
 Authors@R: c(
     person("Yihui", "Xie", role = c("aut", "cre"), email = "[email protected]", comment = c(ORCID = "0000-0003-0645-5666")),
     person("Abhraneel", "Sarma", role = "ctb"),

NEWS.md

@@ -18,6 +18,8 @@
 
 - The `opts_current` object can no longer be modified within code chunks via its `$set()` method (thanks, @AshesITR, #1798).
 
+- The argument `col.names` of `kable()` can be used to specify the column name of row names now, e.g., `kable(head(mtcars), col.names = c("car", names(mtcars)))` (`"car"` will be the column name of row names in the first column) (thanks, @iago-pssjd, #1933).
+
 ## MAJOR CHANGES
 
 - Dashes (`-`) in the names of all chunk options are normalized to dots (`.`) now, e.g., `fig-height` will be converted to `fig.height`. This is to make **knitr** more compatible with Quarto since Quarto always use dashes in chunk option names (#2282).

R/table.R

@@ -142,7 +142,7 @@ kable = function(
   if (!is.null(align)) align = rep(align, length.out = m)
   if (row.names) {
     x = cbind(' ' = rownames(x), x)
-    if (!is.null(col.names)) col.names = c(' ', col.names)
+    if (!is.null(col.names)) col.names = tail(c(' ', col.names), ncol(x))
     if (!is.null(align)) align = c('l', align)  # left align row names
   }
   n = nrow(x)

tests/testit/test-table.R

@@ -12,6 +12,11 @@ assert('kable() does not discard row names when there is only one row', {
   (kable2(m) %==% c('|   |  x|  y|', '|:--|--:|--:|', '|a  |  1|  2|'))
 })
 
+assert('kable() can assign a column name for row names', {
+  (kable2(m, col.names = c('z', colnames(m))) %==%
+     c('|z  |  x|  y|', '|:--|--:|--:|', '|a  |  1|  2|'))
+})
+
 assert('kable() recycles the align argument correctly', {
   (kable2(m, align = 'c') %==%
      c('|   | x | y |', '|:--|:-:|:-:|', '|a  | 1 | 2 |'))