Merge pull request #4 from raisadz/duckdb-relational-strip-chars

feat: add `strip_chars` to duckdb

narwhals/_duckdb/expr.py

@@ -591,6 +591,24 @@ def to_uppercase(self) -> DuckDBExpr:
             returns_scalar=False,
         )
 
+    def strip_chars(self, characters: str | None) -> DuckDBExpr:
+        import string
+
+        from duckdb import ConstantExpression
+        from duckdb import FunctionExpression
+
+        return self._compliant_expr._from_call(
+            lambda _input: FunctionExpression(
+                "trim",
+                _input,
+                ConstantExpression(
+                    string.whitespace if characters is None else characters
+                ),
+            ),
+            "strip_chars",
+            returns_scalar=False,
+        )
+
 
 class DuckDBExprDateTimeNamespace:
     def __init__(self, expr: DuckDBExpr) -> None: