Feature: add Grid.from_txt method

.gitignore

@@ -55,3 +55,6 @@ PYPI_VERSION
 build/
 wheelhouse/
 _build/
+
+# Jupyter Notebook
+.ipynb_checkpoints

docs/examples/utils/grid_from_txt_examples.ipynb

@@ -28,13 +28,22 @@
     "- A _transformer_ is defined as `<from_node> <to_node> transformer`\n",
     "  - e.g.: `8 9 transformer`\n",
     "- A _grid opening_ is defined by adding `open`\n",
-    "  - e.g.: `4 5 open` for _lines_ or `6 7 transformer,open` for _transformers_\n",
-    "\n",
+    "  - e.g.: `4 5 open` for _lines_ or `6 7 transformer,open` for _transformers_\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
     "### Loading a drawn grid into pgm-ds\n",
     "\n",
-    "Once you've created a grid, copy the _Graph Data_ of your grid to a text file (e.g. `my_grid.txt`).\n",
+    "There are two ways of loading a text grid into a pgm-ds:\n",
+    "- load grid from a .txt file\n",
+    "- load grid from a list of strings\n",
     "\n",
-    "For example, your file could contain the following data:\n",
+    "#### Load a grid from a .txt file\n",
+    "Copy the _Graph Data_ of your grid to a text file (e.g. `my_grid.txt`).\n",
+    "For the example above, the file should contain the following data:\n",
     "\n",
     "```text\n",
     "S1 2\n",
@@ -52,7 +61,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": 9,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -68,12 +77,36 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "**You should now have a grid loaded from your drawn graph data!**\n"
+    "\n",
+    "#### Load grid from a list of strings\n",
+    "You can also load a grid directly from a list of strings"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from power_grid_model_ds import Grid\n",
+    "\n",
+    "grid = Grid.from_txt(\n",
+    "    [\n",
+    "        \"S1 2\",\n",
+    "        \"S1 3 open\",\n",
+    "        \"2 7\",\n",
+    "        \"3 5\",\n",
+    "        \"3 6 transformer\",\n",
+    "        \"5 7\",\n",
+    "        \"7 8\",\n",
+    "        \"8 9\",\n",
+    "    ]\n",
+    ")"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": 10,
    "metadata": {},
    "outputs": [
     {
@@ -99,7 +132,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": ".venv",
+   "display_name": "Python 3 (ipykernel)",
    "language": "python",
    "name": "python3"
   },
@@ -113,9 +146,9 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.12.3"
+   "version": "3.13.1"
   }
  },
  "nbformat": 4,
- "nbformat_minor": 2
+ "nbformat_minor": 4
 }

src/power_grid_model_ds/_core/model/grids/_text_sources.py

@@ -5,7 +5,7 @@
 """Create a grid from text a text file"""
 
 import logging
-from pathlib import Path
+import re
 from typing import TYPE_CHECKING
 
 from power_grid_model_ds._core.model.enums.nodes import NodeType
@@ -35,32 +35,33 @@ class TextSource:
     def __init__(self, grid_class: type["Grid"]):
         self.grid = grid_class.empty()
 
-    def load_grid_from_path(self, path: Path):
-        """Load assets from text file & sort them by id so that
-        they are ready to be appended to the grid"""
+    def load_from_txt(self, *args: str) -> "Grid":
+        """Load a grid from text"""
 
-        txt_nodes, txt_branches = self.read_txt(path)
+        text_lines = [line for arg in args for line in arg.strip().split("\n")]
+
+        txt_nodes, txt_branches = self.read_txt(text_lines)
         self.add_nodes(txt_nodes)
         self.add_branches(txt_branches)
         self.grid.set_feeder_ids()
         return self.grid
 
     @staticmethod
-    def read_txt(path: Path) -> tuple[set, dict]:
+    def read_txt(txt_lines: list[str]) -> tuple[set, dict]:
         """Extract assets from text"""
-        with open(path, "r", encoding="utf-8") as f:
-            txt_rows = f.readlines()
-
         txt_nodes = set()
         txt_branches = {}
-        for text_line in txt_rows:
+        for text_line in txt_lines:
             if not text_line.strip() or text_line.startswith("#"):
                 continue  # skip empty lines and comments
-            try:
-                from_node_str, to_node_str, *comments = text_line.strip().split(" ")
-            except ValueError as err:
-                raise ValueError(f"Text line '{text_line}' is invalid. Skipping...") from err
-            comments = comments[0].split(",") if comments else []
+
+            pattern = re.compile(r"^\s*(\S+)\s+(\S+)(?:\s+(\S+))?\s*$")
+            match = pattern.match(text_line)
+            if not match:
+                raise ValueError(f"Text line '{text_line}' is invalid. Skipping...")
+
+            from_node_str, to_node_str, comment = match.groups()
+            comments = comment.split(",") if comment else []
 
             txt_nodes |= {from_node_str, to_node_str}
             txt_branches[(from_node_str, to_node_str)] = comments
@@ -116,4 +117,4 @@ def add_branch(self, branch: tuple[str, str], comments: list[str]):
             new_branch.to_status = 0
         else:
             new_branch.to_status = 1
-        self.grid.append(new_branch)
+        self.grid.append(new_branch, check_max_id=False)

src/power_grid_model_ds/_core/model/grids/base.py

@@ -408,6 +408,21 @@ def _from_pickle(cls, pickle_path: Path):
             raise TypeError(f"{pickle_path.name} is not a valid {cls.__name__} cache.")
         return grid
 
+    @classmethod
+    def from_txt(cls, *args: str):
+        """Build a grid from a list of strings
+
+        See the documentation for the expected format of the txt_lines
+
+        Args:
+            *args (str): The lines of the grid
+
+        Examples:
+            >>> Grid.from_txt("1 2", "2 3", "3 4 transformer", "4 5", "S1 6")
+            alternative: Grid.from_txt("1 2\n2 3\n3 4 transformer\n4 5\nS1 6")
+        """
+        return TextSource(grid_class=cls).load_from_txt(*args)
+
     @classmethod
     # pylint: disable=arguments-differ
     def from_txt_file(cls, txt_file_path: Path):
@@ -416,8 +431,9 @@ def from_txt_file(cls, txt_file_path: Path):
         Args:
             txt_file_path (Path): The path to the txt file
         """
-        text_source = TextSource(grid_class=cls)
-        return text_source.load_grid_from_path(txt_file_path)
+        with open(txt_file_path, "r", encoding="utf-8") as f:
+            txt_lines = f.readlines()
+        return TextSource(grid_class=cls).load_from_txt(*txt_lines)
 
     def set_feeder_ids(self):
         """Sets feeder and substation id properties in the grids arrays"""

tests/unit/model/grids/test_grid_base.py

@@ -266,56 +266,84 @@ def test_grid_make_inactive_to_side(basic_grid):
     assert 0 == target_line_after.to_status
 
 
-def test_from_txt_file(tmp_path):
-    """Test that Grid can be created from txt file"""
-    txt_file = tmp_path / "tmp_grid"
-    txt_file.write_text("S1 2\nS1 3 open\n2 7\n3 5\n3 6 transformer\n5 7\n7 8\n8 9", encoding="utf-8")
-    grid = Grid.from_txt_file(txt_file)
-    txt_file.unlink()
-
-    assert 8 == grid.node.size
-    assert 1 == grid.branches.filter(to_status=0).size
-    assert 1 == grid.transformer.size
-    np.testing.assert_array_equal([14, 10, 11, 12, 13, 15, 16, 17], grid.branches.id)
-
-
-def test_from_txt_file_with_branch_ids(tmp_path):
-    txt_file = tmp_path / "tmp_grid"
-    txt_file.write_text(
-        "S1 2 91\nS1 3 92,open\n2 7 93\n3 5 94\n3 6 transformer,95\n5 7 96\n7 8 97\n8 9 98", encoding="utf-8"
-    )
-    grid = Grid.from_txt_file(txt_file)
-    txt_file.unlink()
-
-    assert 8 == grid.node.size
-    assert 1 == grid.branches.filter(to_status=0).size
-    assert 1 == grid.transformer.size
-    np.testing.assert_array_equal([95, 91, 92, 93, 94, 96, 97, 98], grid.branches.id)
-
-
-def test_from_txt_file_conflicting_ids(tmp_path):
-    txt_file = tmp_path / "tmp_grid"
-    txt_file.write_text("S1 2\n1 3", encoding="utf-8")
-
-    with pytest.raises(ValueError):
-        Grid.from_txt_file(txt_file)
-
-    txt_file.unlink()
-
-
-def test_from_txt_file_with_unordered_node_ids(tmp_path):
-    txt_file = tmp_path / "tmp_grid"
-    txt_file.write_text("S1 2\nS1 10\n10 11\n2 5\n5 6\n3 4\n3 7", encoding="utf-8")
-    grid = Grid.from_txt_file(txt_file)
-    txt_file.unlink()
-
-    assert 9 == grid.node.size
-
-
 def test_grid_as_str(basic_grid):
     grid = basic_grid
 
     grid_as_string = str(grid)
 
     assert "102 106 301,transformer" in grid_as_string
     assert "103 104 203,open" in grid_as_string
+
+
+class TestFromTxt:
+    def test_from_txt_lines(self):
+        grid = Grid.from_txt(
+            "S1 2",
+            "S1 3 open",
+            "2 7",
+            "3 5",
+            "3 6 transformer",
+            "5 7",
+            "7 8",
+            "8 9",
+        )
+        assert 8 == grid.node.size
+        assert 1 == grid.branches.filter(to_status=0).size
+        assert 1 == grid.transformer.size
+        np.testing.assert_array_equal([14, 10, 11, 12, 13, 15, 16, 17], grid.branches.id)
+
+    def test_from_txt_string(self):
+        txt_string = "S1 2\nS1 3 open\n2 7\n3 5\n3 6 transformer\n5 7\n7 8\n8 9"
+        assert Grid.from_txt(txt_string)
+
+    def test_from_txt_string_with_spaces(self):
+        txt_string = "S1 2     \nS1 3   open\n2    7\n3 5\n   3 6 transformer\n5 7\n7   8\n8 9"
+        assert Grid.from_txt(txt_string)
+
+    def test_from_docstring(self):
+        assert Grid.from_txt("""
+        S1 2
+        S1 3 open
+        2 7
+        3 5
+        3 6 transformer
+        5 7
+        7 8
+        8 9
+        """)
+
+    def test_from_txt_with_branch_ids(self):
+        grid = Grid.from_txt(
+            "S1 2 91", "S1 3 92,open", "2 7 93", "3 5 94", "3 6 transformer,95", "5 7 96", "7 8 97", "8 9 98"
+        )
+        assert 8 == grid.node.size
+        assert 1 == grid.branches.filter(to_status=0).size
+        assert 1 == grid.transformer.size
+        np.testing.assert_array_equal([95, 91, 92, 93, 94, 96, 97, 98], grid.branches.id)
+
+    def test_from_txt_with_conflicting_ids(self):
+        with pytest.raises(ValueError):
+            Grid.from_txt("S1 2", "1 3")
+
+    def test_from_txt_with_invalid_line(self):
+        with pytest.raises(ValueError):
+            Grid.from_txt("S1 2 arg3 arg4")
+
+    def test_from_txt_with_unordered_node_ids(self):
+        grid = Grid.from_txt("S1 2", "S1 10", "10 11", "2 5", "5 6", "3 4", "3 7")
+        assert 9 == grid.node.size
+
+    def test_from_txt_with_unordered_branch_ids(self):
+        grid = Grid.from_txt("5 6 16", "3 4 17", "3 7 18", "S1 2 12", "S1 10 13", "10 11 14", "2 5 15")
+        assert 9 == grid.node.size
+
+    def test_from_txt_file(self, tmp_path):
+        txt_file = tmp_path / "tmp_grid"
+        txt_file.write_text("S1 2\nS1 3 open\n2 7\n3 5\n3 6 transformer\n5 7\n7 8\n8 9", encoding="utf-8")
+        grid = Grid.from_txt_file(txt_file)
+        txt_file.unlink()
+
+        assert 8 == grid.node.size
+        assert 1 == grid.branches.filter(to_status=0).size
+        assert 1 == grid.transformer.size
+        np.testing.assert_array_equal([14, 10, 11, 12, 13, 15, 16, 17], grid.branches.id)