Added skip_absent arguement to colnamesInt()

NEWS.md

@@ -32,6 +32,8 @@
 
 8. Computations in `j` can return a matrix or array _if it is one-dimensional_, e.g. a row or column vector, when `j` is a list of columns during grouping, [#783](https://github.com/Rdatatable/data.table/issues/783). Previously a matrix could be provided `DT[, expr, by]` form, but not `DT[, list(expr), by]` form; this resolves that inconsistency. It is still an error to return a "true" array, e.g. a `2x3` matrix.
 
+9. Added the `skip_absent` argument to the `colnamesInt()` function, allowing users to continue execution without interruption when set to `TRUE` [#6067](https://github.com/Rdatatable/data.table/issues/6067), even in cases where some columns are absent. This enhancement provides users with greater control over error handling and streamlines the workflow, particularly in scenarios where missing columns are expected or acceptable. Thanks @Nj221102 for the contribution!
+
 ## BUG FIXES
 
 1. `unique()` returns a copy the case when `nrows(x) <= 1` instead of a mutable alias, [#5932](https://github.com/Rdatatable/data.table/pull/5932). This is consistent with existing `unique()` behavior when the input has no duplicates but more than one row. Thanks to @brookslogan for the report and @dshemetov for the fix.

R/wrappers.R

@@ -8,7 +8,7 @@ setcoalesce = function(...) .Call(Ccoalesce, list(...), TRUE)
 fifelse = function(test, yes, no, na=NA) .Call(CfifelseR, test, yes, no, na)
 fcase   = function(..., default=NA) .Call(CfcaseR, default, parent.frame(), as.list(substitute(list(...)))[-1L])
 
-colnamesInt = function(x, cols, check_dups=FALSE) .Call(CcolnamesInt, x, cols, check_dups)
+colnamesInt = function(x, cols, check_dups=FALSE, skip_absent=FALSE) .Call(CcolnamesInt, x, cols, check_dups, skip_absent)
 
 testMsg = function(status=0L, nx=2L, nk=2L) .Call(CtestMsgR, as.integer(status)[1L], as.integer(nx)[1L], as.integer(nk)[1L])
 

inst/tests/nafill.Rraw

@@ -149,8 +149,15 @@ test(4.20, colnamesInt(dt, integer()), integer())
 test(4.21, colnamesInt(dt, NULL), seq_along(dt))
 test(4.22, colnamesInt("asd", 1), error="must be data.table compatible")
 test(4.23, colnamesInt(dt, 1, check_dups="a"), error="check_dups")
+test(4.24, colnamesInt(dt, c("a", "e"), skip_absent = TRUE),as.integer(c(1,0)))
+test(4.25, colnamesInt(dt, c(1L, 4L), skip_absent = TRUE), as.integer(c(1,4)))
+test(4.26, colnamesInt(dt, c(1, 4), skip_absent = TRUE),as.integer( c(1,4)))
+test(4.27, colnamesInt(dt, c("a", NA), skip_absent = TRUE),as.integer(c(1,0)))
+test(4.28, colnamesInt(dt, c(1L, NA), skip_absent = TRUE), as.integer(c(1,NA)))
+test(4.29, colnamesInt(dt, c(1, NA), skip_absent = TRUE), as.integer(c(1,NA)))
 names(dt) <- NULL
-test(4.24, colnamesInt(dt, "a"), error="has no names")
+test(4.30, colnamesInt(dt, "a"), error="has no names")
+
 
 # verbose
 dt = data.table(a=c(1L, 2L, NA_integer_), b=c(1, 2, NA_real_))

src/data.table.h

@@ -238,7 +238,7 @@ bool isRealReallyInt(SEXP x);
 SEXP isRealReallyIntR(SEXP x);
 SEXP isReallyReal(SEXP x);
 bool allNA(SEXP x, bool errorForBadType);
-SEXP colnamesInt(SEXP x, SEXP cols, SEXP check_dups);
+SEXP colnamesInt(SEXP x, SEXP cols, SEXP check_dups, SEXP skip_absent);
 bool INHERITS(SEXP x, SEXP char_);
 SEXP copyAsPlain(SEXP x);
 void copySharedColumns(SEXP x);

src/nafill.c

@@ -114,7 +114,7 @@ SEXP nafillR(SEXP obj, SEXP type, SEXP fill, SEXP nan_is_na_arg, SEXP inplace, S
     obj = PROTECT(allocVector(VECSXP, 1)); protecti++; // wrap into list
     SET_VECTOR_ELT(obj, 0, obj1);
   }
-  SEXP ricols = PROTECT(colnamesInt(obj, cols, ScalarLogical(TRUE))); protecti++; // nafill cols=NULL which turns into seq_along(obj)
+  SEXP ricols = PROTECT(colnamesInt(obj, cols, ScalarLogical(TRUE), ScalarLogical(FALSE))); protecti++; // nafill cols=NULL which turns into seq_along(obj)
   x = PROTECT(allocVector(VECSXP, length(ricols))); protecti++;
   int *icols = INTEGER(ricols);
   for (int i=0; i<length(ricols); i++) {

src/utils.c

@@ -99,14 +99,17 @@ SEXP allNAR(SEXP x) {
  *   existing columns for character
  *   optionally check for no duplicates
  */
-SEXP colnamesInt(SEXP x, SEXP cols, SEXP check_dups) {
+SEXP colnamesInt(SEXP x, SEXP cols, SEXP check_dups, SEXP skip_absent) {
   if (!isNewList(x))
     error(_("'x' argument must be data.table compatible"));
   if (!IS_TRUE_OR_FALSE(check_dups))
     error(_("%s must be TRUE or FALSE"), "check_dups");
+  if (!IS_TRUE_OR_FALSE(skip_absent))
+    error(_("skip_absent must be TRUE or FALSE"));
   int protecti = 0;
   R_len_t nx = length(x);
   R_len_t nc = length(cols);
+  bool Skip_absent = LOGICAL(skip_absent)[0];
   SEXP ricols = R_NilValue;
   if (isNull(cols)) { // seq_along(x)
     ricols = PROTECT(allocVector(INTSXP, nx)); protecti++;
@@ -124,7 +127,7 @@ SEXP colnamesInt(SEXP x, SEXP cols, SEXP check_dups) {
     }
     int *icols = INTEGER(ricols);
     for (int i=0; i<nc; i++) {
-      if ((icols[i]>nx) || (icols[i]<1))
+      if (((icols[i]>nx) || (icols[i]<1)) && !Skip_absent)
         error(_("argument specifying columns received non-existing column(s): cols[%d]=%d"), i+1, icols[i]); // handles NAs also
     }
   } else if (isString(cols)) {
@@ -134,7 +137,7 @@ SEXP colnamesInt(SEXP x, SEXP cols, SEXP check_dups) {
     ricols = PROTECT(chmatch(cols, xnames, 0)); protecti++;
     int *icols = INTEGER(ricols);
     for (int i=0; i<nc; i++) {
-      if (icols[i]==0)
+      if (icols[i]==0 && !Skip_absent)
         error(_("argument specifying columns received non-existing column(s): cols[%d]='%s'"), i+1, CHAR(STRING_ELT(cols, i))); // handles NAs also
     }
   } else {