diff --git a/src/kyupy/circuit.py b/src/kyupy/circuit.py
index 53b2e51..d2febf8 100644
--- a/src/kyupy/circuit.py
+++ b/src/kyupy/circuit.py
@@ -6,6 +6,7 @@ and a line is an instance of class :class:`Line`.
 """
 
 from collections import deque
+import re
 
 
 class GrowingList(list):
@@ -371,3 +372,22 @@ class Circuit:
                 queue.extend(preds)
                 region.append(n)
             yield stem, region
+
+    def io_loc(self, prefix):
+        d_top = dict()
+        for i, n in enumerate(self.interface):
+            if m := re.match(fr'({prefix}.*?)((?:[_\[\]]\d+)*[_\[\]]*$)', n.name):
+                path = [m[1]] + [int(v) for v in re.split(r'[_\[\]]+', m[2]) if len(v) > 0]
+                d = d_top
+                for j in path[:-1]:
+                    d[j] = d.get(j, dict())
+                    d = d[j]
+                d[path[-1]] = i
+
+        def sorted_values(d):
+            return [sorted_values(v) for k, v in sorted(d.items())] if isinstance(d, dict) else d
+        
+        l = sorted_values(d_top)
+        while isinstance(l, list) and len(l) == 1: l = l[0]
+
+        return l