Add combinedType min and max, fixes #62

adtl/__init__.py

@@ -228,18 +228,11 @@ def get_combined_type(row: StrDict, rule: StrDict, ctx: Context = None):
                 rules.append({"field": match, **r})
         else:
             rules.append(r)
-    if combined_type == "all":
+    if combined_type in ["all", "any", "min", "max"]:
         values = [get_value(row, r, ctx) for r in rules]
-        if all(v is None for v in values):
-            return None
-        else:
-            return all(values)
-    elif combined_type == "any":
-        values = [get_value(row, r, ctx) for r in rules]
-        if all(v is None for v in values):
-            return None
-        else:
-            return any(values)
+        values = [v for v in values if v not in [None, ""]]
+        # normally calling eval() is a bad idea, but here values are restricted, so okay
+        return eval(combined_type)(values) if values else None
     elif combined_type == "firstNonNull":
         try:
             return next(

docs/specification.md

@@ -227,6 +227,8 @@ Accepted values for `combinedType` are:
 
 * *any* - Whether any of the fields are non-null (truthy)
 * *all* - Whether all of the fields are non-null (truthy)
+* *min* - Minimum of non-null fields
+* *max* - Minimum of non-null fields
 * *firstNonNull* - First in the list of fields that has a non-null value
 * *list* - List of various fields
 * *set* - List of various fields, with duplicates removed

tests/test_parser.py

@@ -59,6 +59,17 @@
     "source_unit": {"field": "age_unit", "values": {"1": "months", "2": "years"}},
 }
 
+ROW_DATE_BOTH_PRESENT = {"admission_date": "2020-05-05", "enrolment_date": "2020-05-19"}
+ROW_DATE_ONLY_ONE = {"admission_date": "2020-05-05", "enrolment_date": ""}
+RULE_COMBINED_TYPE_MIN = {  # earliest date
+    "combinedType": "min",
+    "fields": [{"field": "admission_date"}, {"field": "enrolment_date"}],
+}
+RULE_COMBINED_TYPE_MAX = {  # latest date
+    "combinedType": "max",
+    "fields": [{"field": "admission_date"}, {"field": "enrolment_date"}],
+}
+
 RULE_COMBINED_TYPE_ANY = {"combinedType": "any", "fields": LIVER_DISEASE}
 RULE_COMBINED_TYPE_ALL = {"combinedType": "all", "fields": LIVER_DISEASE}
 RULE_COMBINED_FIRST_NON_NULL = {
@@ -313,6 +324,12 @@
         ((ROW_CONDITIONAL, RULE_CONDITIONAL_FAIL), None),
         ((ROW_UNIT_MONTH, RULE_UNIT), 1.5),
         ((ROW_UNIT_YEAR, RULE_UNIT), 18),
+        ((ROW_DATE_BOTH_PRESENT, RULE_COMBINED_TYPE_MIN), "2020-05-05"),
+        ((ROW_DATE_BOTH_PRESENT, RULE_COMBINED_TYPE_MAX), "2020-05-19"),
+        ((ROW_DATE_ONLY_ONE, RULE_COMBINED_TYPE_MIN), "2020-05-05"),
+        ((ROW_DATE_ONLY_ONE, RULE_COMBINED_TYPE_MAX), "2020-05-05"),
+        (({"admission_date": "", "enrolment_date": ""}, RULE_COMBINED_TYPE_MIN), None),
+        (({"admission_date": "", "enrolment_date": ""}, RULE_COMBINED_TYPE_MAX), None),
         (({"outcome_date": "02/05/2022"}, RULE_DATE_MDY), "05/02/2022"),
         (({"outcome_date": "02/05/2022"}, RULE_DATE_ISO), "2022-05-02"),
         (