feat: Added Column#transform

src/safeds/data/tabular/containers/_column.py

@@ -24,6 +24,7 @@
     from collections.abc import Callable, Iterator
 
 T = TypeVar("T")
+R = TypeVar("R")
 
 
 class Column(Sequence[T]):
@@ -300,6 +301,8 @@ def rename(self, new_name: str) -> Column:
         """
         Return a new column with a new name.
 
+        This column is not modified.
+
         Parameters
         ----------
         new_name : str
@@ -312,6 +315,30 @@ def rename(self, new_name: str) -> Column:
         """
         return Column._from_pandas_series(self._data.rename(new_name), self._type)
 
+    def transform(self, transformer: Callable[[T], R]) -> Column[R]:
+        """
+        Apply a transform method to every data point.
+
+        This column is not modified.
+
+        Parameters
+        ----------
+        transformer : Callable[[T], R]
+            Function that will be applied to all data points.
+
+        Returns
+        -------
+        transformed_column: Column
+            The transformed column.
+
+        Examples
+        --------
+        >>> from safeds.data.tabular.containers import Column
+        >>> price = Column("price", [4.99, 5.99, 2.49])
+        >>> sale = price.transform(lambda amount: amount * 0.8)
+        """
+        return Column(self.name, self._data.apply(transformer, convert_dtype=True))
+
     # ------------------------------------------------------------------------------------------------------------------
     # Statistics
     # ------------------------------------------------------------------------------------------------------------------

tests/safeds/data/tabular/containers/_column/test_transform.py

@@ -0,0 +1,29 @@
+import pytest
+from safeds.data.tabular.containers import Column
+
+
+@pytest.mark.parametrize(
+    ("column", "expected"),
+    [
+        (Column("test", []), Column("test", [])),
+        (Column("test", [1, 2]), Column("test", [2, 3])),
+        (Column("test", [-0.5, 0, 4]), Column("test", [0.5, 1, 5])),
+    ],
+    ids=["empty", "integers", "floats"],
+)
+def test_should_transform_column(column: Column, expected: Column) -> None:
+    assert column.transform(lambda it: it + 1) == expected
+
+
+@pytest.mark.parametrize(
+    ("column", "original"),
+    [
+        (Column("test", []), Column("test", [])),
+        (Column("test", [1, 2]), Column("test", [1, 2])),
+        (Column("test", [-0.5, 0, 4]), Column("test", [-0.5, 0, 4])),
+    ],
+    ids=["empty", "integers", "floats"],
+)
+def test_should_not_change_original_column(column: Column, original: Column) -> None:
+    column.transform(lambda it: it + 1)
+    assert column == original