Merge pull request #3 from jmespath-community/jep/grouping

JEP-18 Grouping

Author: springcomp

jmespath/functions.py

@@ -1,6 +1,8 @@
 import math
 import json
 
+from collections import OrderedDict
+
 from jmespath import exceptions
 from jmespath.compat import get_methods
 from jmespath.compat import iteritems
@@ -533,6 +535,19 @@ def _func_max_by(self, array, expref):
     def _func_zip(self, *arguments):
         return list(map(list, zip(*arguments)))
 
+    @signature({'types': ['array']}, {'types': ['expref']})
+    def _func_group_by(self, array, expref):
+        keyfunc = self._create_key_func(expref, ['null', 'string'], 'group_by')
+        if array:
+            result = OrderedDict()
+            keys = list(dict.fromkeys([keyfunc(item) for item in array if keyfunc(item) != None]))
+            for key in keys:
+                items = [ item for item in array if keyfunc(item) == key ]
+                result.update({key: items})
+            return result
+        else:
+            return None
+
     def _create_key_func(self, expref, allowed_types, function_name):
         def keyfunc(x):
             result = expref.visit(expref.expression, x)

tests/compliance/group_by_function.json

@@ -0,0 +1,132 @@
+[
+	{
+		"given": {
+			"items": [
+				{
+					"spec": {
+						"nodeNumber": 1,
+						"nodeName": "node_01",
+						"other": "values_01"
+					}
+				},
+				{
+					"spec": {
+						"nodeNumber": 2,
+						"nodeName": "node_02",
+						"other": "values_02"
+					}
+				},
+				{
+					"spec": {
+						"nodeNumber": 3,
+						"nodeName": "node_03",
+						"other": "values_03"
+					}
+				},
+				{
+					"spec": {
+						"nodeNumber": 1,
+						"nodeName": "node_01",
+						"other": "values_04"
+					}
+				}
+			]
+		},
+		"cases": [
+			{
+				"expression": "group_by(@, &`false`)",
+				"error": "invalid-type"
+			},
+			{
+				"expression": "group_by(keys(items[*].spec|[0]), &`false`)",
+				"error": "invalid-type"
+			},
+			{
+				"expression": "group_by(items, spec.nodeName)",
+				"error": "invalid-type"
+			},
+			{
+				"expression": "group_by(items, &spec.nodeName)",
+				"result": {
+					"node_01": [
+						{
+							"spec": {
+								"nodeNumber": 1,
+								"nodeName": "node_01",
+								"other": "values_01"
+							}
+						},
+						{
+							"spec": {
+								"nodeNumber": 1,
+								"nodeName": "node_01",
+								"other": "values_04"
+							}
+						}
+					],
+					"node_02": [
+						{
+							"spec": {
+								"nodeNumber": 2,
+								"nodeName": "node_02",
+								"other": "values_02"
+							}
+						}
+					],
+					"node_03": [
+						{
+							"spec": {
+								"nodeNumber": 3,
+								"nodeName": "node_03",
+								"other": "values_03"
+							}
+						}
+					]
+				}
+			},
+			{
+				"expression": "group_by(items, &to_string(spec.nodeNumber))",
+				"result": {
+					"1": [
+						{
+							"spec": {
+								"nodeNumber": 1,
+								"nodeName": "node_01",
+								"other": "values_01"
+							}
+						},
+						{
+							"spec": {
+								"nodeNumber": 1,
+								"nodeName": "node_01",
+								"other": "values_04"
+							}
+						}
+					],
+					"2": [
+						{
+							"spec": {
+								"nodeNumber": 2,
+								"nodeName": "node_02",
+								"other": "values_02"
+							}
+						}
+					],
+					"3": [
+						{
+							"spec": {
+								"nodeNumber": 3,
+								"nodeName": "node_03",
+								"other": "values_03"
+							}
+						}
+					]
+				}
+			},
+			{
+				"expression": "group_by(items, &spec.nodeNumber)",
+				"error": "invalid-type"
+			}
+		]
+	}
+]