fixup cast to string for pandas (#254)

narwhals/_pandas_like/utils.py

@@ -437,7 +437,6 @@ def reverse_translate_dtype(  # noqa: PLR0915
     from narwhals import dtypes
 
     dtype_backend = get_dtype_backend(starting_dtype, implementation)
-
     if isinstance_or_issubclass(dtype, dtypes.Float64):
         if dtype_backend == "pyarrow-nullable":
             return "Float64[pyarrow]"
@@ -514,7 +513,7 @@ def reverse_translate_dtype(  # noqa: PLR0915
         if dtype_backend == "pandas-nullable":
             return "string"
         else:
-            return object
+            return str
     if isinstance_or_issubclass(dtype, dtypes.Boolean):
         if dtype_backend == "pyarrow-nullable":
             return "boolean[pyarrow]"

tests/series/cast_test.py

@@ -0,0 +1,18 @@
+import pandas as pd
+import polars as pl
+
+import narwhals as nw
+
+
+def test_cast_253() -> None:
+    df_polars = pl.DataFrame({"a": [1]})
+    result = nw.from_native(df_polars, eager_only=True).select(
+        nw.col("a").cast(nw.String) + "hi"
+    )["a"][0]
+    assert result == "1hi"
+
+    df_pandas = pd.DataFrame({"a": [1]})
+    result = nw.from_native(df_pandas, eager_only=True).select(
+        nw.col("a").cast(nw.String) + "hi"
+    )["a"][0]
+    assert result == "1hi"