Since this thing is on the innerwebs I suppose it should have a

[python_utils.git] / collect / trie.py

diff --git a/collect/trie.py b/collect/trie.py
index b9a5a1adbcd91cb96b593ac62b9eb5db7bdb6cc5..547d67a4124abc07f425ecf21616bf2c509beb4e 100644 (file)
--- a/collect/trie.py
+++ b/collect/trie.py
@@ -1,6 +1,15 @@
 #!/usr/bin/env python3
 
-from typing import Any, Sequence
+# © Copyright 2021-2022, Scott Gasch
+
+"""This is a Trie class, see: https://en.wikipedia.org/wiki/Trie.
+
+It attempts to follow Pythonic container patterns.  See doctests
+for examples.
+
+"""
+
+from typing import Any, Generator, Sequence
 
 
 class Trie(object):
@@ -11,10 +20,13 @@ class Trie(object):
     for examples.
 
     """
+
     def __init__(self):
         self.root = {}
         self.end = "~END~"
         self.length = 0
+        self.viz = ''
+        self.content_generator: Generator[str] = None
 
     def insert(self, item: Sequence[Any]):
         """
@@ -240,7 +252,43 @@ class Trie(object):
             return None
         return [x for x in node if x != self.end]
 
-    def repr_recursive(self, node, delimiter):
+    def repr_fancy(
+        self,
+        padding: str,
+        pointer: str,
+        node: Any,
+        has_sibling: bool,
+    ):
+        if node is None:
+            return ''
+        if node is not self.root:
+            ret = f'\n{padding}{pointer}'
+            if has_sibling:
+                padding += '│  '
+            else:
+                padding += '   '
+        else:
+            ret = f'{pointer}'
+
+        child_count = 0
+        for child in node:
+            if child != self.end:
+                child_count += 1
+
+        for child in node:
+            if child != self.end:
+                if child_count > 1:
+                    pointer = "├──"
+                    has_sibling = True
+                else:
+                    pointer = "└──"
+                    has_sibling = False
+                pointer += f'{child}'
+                child_count -= 1
+                ret += self.repr_fancy(padding, pointer, node[child], has_sibling)
+        return ret
+
+    def repr_brief(self, node, delimiter):
         """
         A friendly string representation of the contents of the Trie.
 
@@ -249,10 +297,8 @@ class Trie(object):
         >>> t.insert([10, 0, 0, 2])
         >>> t.insert([10, 10, 10, 1])
         >>> t.insert([10, 10, 10, 2])
-        >>> t.repr_recursive(t.root, '.')
-        '10.[0.0.[1, 2], 10.10.[1, 2]]'
-        >>> print(t)
-        10[00[1, 2], 1010[1, 2]]
+        >>> t.repr_brief(t.root, '.')
+        '10.[0.0.[1,2],10.10.[1,2]]'
 
         """
         child_count = 0
@@ -260,13 +306,13 @@ class Trie(object):
         for child in node:
             if child != self.end:
                 child_count += 1
-                child_rep = self.repr_recursive(node[child], delimiter)
+                child_rep = self.repr_brief(node[child], delimiter)
                 if len(child_rep) > 0:
-                    my_rep += str(child) + delimiter + child_rep + ", "
+                    my_rep += str(child) + delimiter + child_rep + ","
                 else:
-                    my_rep += str(child) + ", "
+                    my_rep += str(child) + ","
         if len(my_rep) > 1:
-            my_rep = my_rep[:-2]
+            my_rep = my_rep[:-1]
         if child_count > 1:
             my_rep = f'[{my_rep}]'
         return my_rep
@@ -274,7 +320,7 @@ class Trie(object):
     def __repr__(self):
         """
         A friendly string representation of the contents of the Trie.  Under
-        the covers uses repr_recursive with no delimiter
+        the covers uses repr_fancy.
 
         >>> t = Trie()
         >>> t.insert([10, 0, 0, 1])
@@ -282,12 +328,22 @@ class Trie(object):
         >>> t.insert([10, 10, 10, 1])
         >>> t.insert([10, 10, 10, 2])
         >>> print(t)
-        10[00[1, 2], 1010[1, 2]]
+        *
+        └──10
+           ├──0
+           │  └──0
+           │     ├──1
+           │     └──2
+           └──10
+              └──10
+                 ├──1
+                 └──2
 
         """
-        return self.repr_recursive(self.root, '')
+        return self.repr_fancy('', '*', self.root, False)
 
 
 if __name__ == '__main__':
     import doctest
+
     doctest.testmod()