add helper method for creating empty canonical dataframe

aaraney · Sep 3, 2021 · 7985320 · 7985320
1 parent 908e000
commit 7985320
Showing 1 changed file with 14 additions and 0 deletions.
diff --git a/python/nwis_client/src/hydrotools/nwis_client/iv.py b/python/nwis_client/src/hydrotools/nwis_client/iv.py
@@ -809,3 +809,17 @@ def flatten_and_stringify(v):
     value_groups = np.array_split(values, n_groups)
 
     return list(map(lambda i: ",".join(i), value_groups))
+
+
+def _create_empty_canonical_df() -> pd.DataFrame:
+    """Returns an empty hydrotools canonical dataframe with correct field datatypes."""
+    cols = {
+        "value_time": pd.Series(dtype="datetime64[ns]"),
+        "variable_name": pd.Series(dtype="category"),
+        "usgs_site_code": pd.Series(dtype="category"),
+        "measurement_unit": pd.Series(dtype="category"),
+        "value": pd.Series(dtype="float32"),
+        "qualifiers": pd.Series(dtype="category"),
+        "series": pd.Series(dtype="category"),
+    }
+    return pd.DataFrame(cols, index=[])