Merge pull request #265 from moj-analytical-services/warn_num_levels

Warn num levels

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "splink"
-version = "2.1.1"
+version = "2.1.2"
 description = "Implementation of Fellegi-Sunter's canonical model of record linkage in Apache Spark, including EM algorithm to estimate parameters"
 authors = ["Robin Linacre <robinlinacre@hotmail.com>", "Sam Lindsay", "Theodore Manassis"]
 license = "MIT"

splink/default_settings.py

@@ -183,12 +183,20 @@ def _complete_comparison_levels(col_settings):
     if "-1" not in keys:
 
         warnings.warn(
-            "No -1 level found in case statement."
+            "\nNo -1 level found in case statement."
             " You usually want to use -1 as the level for the null value."
             " e.g. WHEN col_l is null or col_r is null then -1"
             f" Case statement is:\n {col_settings['case_expression']}."
         )
 
+    if "num_levels" in col_settings:
+        if col_settings["num_levels"] != cc.num_levels:
+            warnings.warn(
+                f"\nnum_levels specified in settings is {col_settings['num_levels']}, "
+                f"but the number of levels in the case statement excluding the null level is {cc.num_levels}"
+                f"\nCase statement is:\n {col_settings['case_expression']}."
+            )
+
 
 def _complete_col_name(col_settings):