feat: add helper function to extract values from matching variables (#96

)

switchwrapper/helpers.py

@@ -1,3 +1,8 @@
+import re
+
+import pandas as pd
+
+
 def make_indices(plant_ids):
     """Make the indices for existing and hypothetical generators for input to Switch.
 
@@ -8,3 +13,27 @@ def make_indices(plant_ids):
     original_plant_indices = [f"g{p}" for p in plant_ids]
     hypothetical_plant_indices = [f"{o}i" for o in original_plant_indices]
     return original_plant_indices, hypothetical_plant_indices
+
+
+def match_variables(variables, pattern, columns):
+    """Search through dictionary of variables, extracting data frame of values.
+
+    :param dict variables: dictionary, keys are strings, values are dictionaries
+        with key "Value" and float value.
+    :param str pattern: regex pattern to use to search for matching variables.
+    :param iterable columns: names to extract from match to data frame columns.
+    :return: (*pandas.DataFrame*) -- data frame of matching variables.
+    """
+    prog = re.compile(pattern)
+    df = pd.DataFrame(
+        [
+            {
+                **{name: m.group(name) for name in columns},
+                "capacity": variables[m.group(0)]["Value"],
+            }
+            for m in [
+                prog.match(v) for v in variables.keys() if prog.match(v) is not None
+            ]
+        ]
+    )
+    return df