Make energy_system.nodes a dict

CHANGELOG.rst

@@ -21,3 +21,4 @@ Changelog
 
 * Improved code quality
 * Add Entity.custom_properties
+* Simplify node access (energy_system.nodes[label])

src/oemof/network/energy_system.py

@@ -141,7 +141,7 @@ def __init__(self, **kwargs):
             g if isinstance(g, Grouping) else Entities(g)
             for g in kwargs.get("groupings", [])
         ]
-        self._nodes = []
+        self._nodes = {}
 
         self.results = kwargs.get("results")
 
@@ -155,7 +155,7 @@ def __init__(self, **kwargs):
 
     def add(self, *nodes):
         """Add :class:`nodes <oemof.network.Node>` to this energy system."""
-        self.nodes.extend(nodes)
+        self._nodes.update({node.label: node for node in nodes})
         for n in nodes:
             self.signals[type(self).add].send(n, EnergySystem=self)
 
@@ -168,20 +168,20 @@ def groups(self):
             (
                 g(n, gs)
                 for g in self._groupings
-                for n in self.nodes[self._first_ungrouped_node_index_ :]
+                for n in list(self.nodes)[self._first_ungrouped_node_index_ :]
             ),
             maxlen=0,
         )
         self._first_ungrouped_node_index_ = len(self.nodes)
         return self._groups
 
     @property
-    def nodes(self):
+    def node(self):
         return self._nodes
 
-    @nodes.setter
-    def nodes(self, value):
-        self._nodes = value
+    @property
+    def nodes(self):
+        return self._nodes.values()
 
     def flows(self):
         return {

src/oemof/network/graph.py

@@ -98,8 +98,8 @@ def create_nx_graph(
     grph = nx.DiGraph()
 
     # add nodes
-    for n in energy_system.nodes:
-        grph.add_node(str(n.label), label=str(n.label))
+    for label in energy_system.node.keys():
+        grph.add_node(str(label), label=str(label))
 
     # add labeled flows on directed edge if an optimization_model has been
     # passed or undirected edge otherwise
@@ -125,7 +125,9 @@ def create_nx_graph(
     if remove_nodes_with_substrings is not None:
         for i in remove_nodes_with_substrings:
             remove_nodes = [
-                str(v.label) for v in energy_system.nodes if i in str(v.label)
+                str(label)
+                for label in energy_system.node.keys()
+                if i in str(label)
             ]
             grph.remove_nodes_from(remove_nodes)
 

tests/test_network_classes.py

@@ -332,13 +332,13 @@ def setup_method(self):
     def test_entity_registration(self):
         n1 = Node(label="<B1>")
         self.es.add(n1)
-        assert self.es.nodes[0] == n1
+        assert self.es.node["<B1>"] == n1
         n2 = Node(label="<B2>")
         self.es.add(n2)
-        assert self.es.nodes[1] == n2
+        assert self.es.node["<B2>"] == n2
         n3 = Node(label="<TF1>", inputs=[n1], outputs=[n2])
         self.es.add(n3)
-        assert n3 in self.es.nodes
+        assert self.es.node["<TF1>"] == n3
 
 
 def test_deprecated_classes():