Export variable and constraint names in LP files

doc/release_notes.rst

@@ -15,6 +15,9 @@ Version 0.4.4
 * Solution files that following a different naming scheme of variables and constraints using more than on initial letter in the prefix (e.g. `col123`, `row456`) are now supported.
 * GLPK solver is always called with the `--freemps` option instead of the `--mps` when using the Solver API to solve an external MPS file. `--mps` is for the older fixed-column MPS format that is rarely used nowadays. Almost all fixed MPS files can be parsed by the free MPS format.
 
+* Added extra argument in io methods `explicit_coordinate_names` to allow for export of
+  variables and constraints with explicit coordinate names.
+
 Version 0.4.3
 --------------
 

linopy/common.py

@@ -43,9 +43,13 @@ def set_int_index(series: pd.Series) -> pd.Series:
     """
     Convert string index to int index.
     """
+
     if not series.empty and not pd.api.types.is_integer_dtype(series.index):
         cutoff = count_initial_letters(str(series.index[0]))
-        series.index = series.index.str[cutoff:].astype(int)
+        try:
+            series.index = series.index.str[cutoff:].astype(int)
+        except ValueError:
+            series.index = series.index.str.replace(".*#", "", regex=True).astype(int)
     return series