upd bfs, dfs on rooted tree

add readme

chapter7/README.md

@@ -0,0 +1,5 @@
+# DFS BFS on rooted tree
+
+The BFS example uses a queue which results in a breadth first search. When a directory is found its contents are appended to the queue to be processed later
+
+The DFS example uses the call stack which results in a depth first search. When a directory is found it is recursively passed to files_with_extension to be processed immediately.

chapter7/bfs_dirtrav.py

@@ -5,23 +5,27 @@ from pathlib import Path
 logging.basicConfig(level=logging.DEBUG)
 logger = logging.getLogger(__name__)
 
+EXT = ".rb"
+
 scripts_path = Path.home() / "scripts"
 
 
-def files_with_extension(ext):
+def files_with_extension(start_directory):
     queue = deque()
-    queue += scripts_path.glob("*")
+    queue.append(start_directory)
 
     while queue:
-        item = queue.popleft()
+        items = queue.popleft()
 
-        # if it is a file and has extension ext then print
-        if item.is_file() and item.suffix == ext:
+        for item in items.glob("*"):
+            # if it is a file and has extension EXT then print
+            if item.is_file():
+                if item.suffix == EXT:
                     print(item)
 
-        # otherwise add directory items to the queue
+            # otherwise append directory to the queue
             else:
-            queue += item.glob("*")
+                queue.append(item)
 
 
-files_with_extension(".sh")
+files_with_extension(scripts_path)

chapter7/dfs_dirtrav.py

@@ -0,0 +1,25 @@
+import logging
+from collections import deque
+from pathlib import Path
+
+logging.basicConfig(level=logging.DEBUG)
+logger = logging.getLogger(__name__)
+
+EXT = ".rb"
+
+scripts_path = Path.home() / "scripts"
+
+
+def files_with_extension(directory):
+    for item in directory.glob("*"):
+        # if it is a file and has extension EXT then print
+        if item.is_file():
+            if item.suffix == EXT:
+                print(item)
+
+        # otherwise pass directory to recursive call
+        else:
+            files_with_extension(item)
+
+
+files_with_extension(scripts_path)