fix: spanners_print_matrix now excludes selected cols that are in the stub

docs/examples/index.qmd

@@ -103,7 +103,7 @@ wide_pops = (
         pl.col("country_code_2").is_in(list(region_to_country))
         & pl.col("year").is_in([2000, 2010, 2020])
     )
-    .with_columns(pl.col("country_code_2").map_dict(region_to_country).alias("region"))
+    .with_columns(pl.col("country_code_2").replace(region_to_country).alias("region"))
     .pivot(index=["country_name", "region"], columns="year", values="population")
     .sort("2020", descending=True)
 )

great_tables/_spanners.py

@@ -502,7 +502,11 @@ def spanners_print_matrix(
 
     for span_ii, span in enumerate(crnt_spans):
         for var in span.vars:
-            label_matrix[span.spanner_level][var] = spanner_reprs[span_ii]
+            # This if clause skips spanned columns that are not in the
+            # boxhead vars we are planning to use (e.g. not in the visible ones
+            # or in the stub).
+            if var in label_matrix[span.spanner_level]:
+                label_matrix[span.spanner_level][var] = spanner_reprs[span_ii]
 
     # reverse order , so if you were to print it out, level 0 would appear on the bottom
     label_matrix.reverse()

tests/test_spanners.py

@@ -74,6 +74,17 @@ def test_spanners_print_matrix_arg_include_hidden(spanners, boxhead):
     ]
 
 
+def test_spanners_print_matrix_exclude_stub():
+    """spanners_print_matrix omits a selected column if it's in the stub."""
+    info = SpannerInfo(spanner_id="a", spanner_level=0, vars=["x", "y"], built="A")
+    spanners = Spanners([info])
+    boxh = Boxhead([ColInfo(var="x"), ColInfo(var="y", type=ColInfoTypeEnum.stub)])
+
+    mat, vars = spanners_print_matrix(spanners, boxh, omit_columns_row=True)
+    assert vars == ["x"]
+    assert mat == [{"x": "A"}]
+
+
 def test_empty_spanner_matrix():
     mat, vars = empty_spanner_matrix(["a", "b"], omit_columns_row=False)