update code comments

chelsea-lin · chelsea-lin · commit ee7be9af7de2 · 2025-10-27T22:06:49.000Z
diff --git a/bigframes/core/compile/sqlglot/expressions/date_ops.py b/bigframes/core/compile/sqlglot/expressions/date_ops.py
@@ -61,7 +61,8 @@ def _(expr: TypedExpr) -> sge.Expression:
 
 # Helpers
 def dayofweek_op_impl(expr: TypedExpr) -> sge.Expression:
-    # Adjust the 1-based day-of-week index (from SQL) to a 0-based index.
+    # BigQuery SQL Extract(DAYOFWEEK) returns 1 for Sunday through 7 for Saturday.
+    # We want 0 for Monday through 6 for Sunday to be compatible with Pandas.
     extract_expr = sge.Extract(
         this=sge.Identifier(this="DAYOFWEEK"), expression=expr.expr
     )

Original file line number	Diff line number	Diff line change
`@@ -61,7 +61,8 @@ def _(expr: TypedExpr) -> sge.Expression:`
`61`	`61`
`62`	`62`	`# Helpers`
`63`	`63`	`def dayofweek_op_impl(expr: TypedExpr) -> sge.Expression:`
`64`		`- # Adjust the 1-based day-of-week index (from SQL) to a 0-based index.`
	`64`	`+ # BigQuery SQL Extract(DAYOFWEEK) returns 1 for Sunday through 7 for Saturday.`
	`65`	`+ # We want 0 for Monday through 6 for Sunday to be compatible with Pandas.`
`65`	`66`	`extract_expr = sge.Extract(`
`66`	`67`	`this=sge.Identifier(this="DAYOFWEEK"), expression=expr.expr`
`67`	`68`	`)`