Lambda in a loop vid

Author: jamesmurphy-mc

README.md

@@ -12,6 +12,7 @@ James and his team are available for consulting, contracting, code reviews, and
 
 | N   | Code | Video | 
 |-----| --- |--- |
+| 129 | [src](videos/129_lambda_in_a_loop_is_a_code_smell) | [Lambda in a Loop is a Code Smell](https://youtu.be/fZE6ZWde-Os) |
 | 128 | [src](videos/128_id_mapping) | [A forbidden Python technique to put ANYTHING in a dict or set.](https://youtu.be/NpdNDTncxwA) |
 | 127 | [src](videos/127_accidentally_quadratic_unique_sum) | [Don't make this big O mistake!](https://youtu.be/PXWL_Xzyrp4) |
 | 126 | [src](videos/126_attrs_revolution) | [Why I prefer attrs over dataclasses](https://youtu.be/1S2h11XronA) |

videos/129_lambda_in_a_loop_is_a_code_smell/main.py

@@ -0,0 +1,51 @@
+import functools
+import threading
+import time
+from collections.abc import Callable
+from concurrent.futures import ThreadPoolExecutor, Future
+
+io_lock = threading.Lock()
+
+
+def print_ts(*args):
+    with io_lock:
+        print(*args)
+
+
+def print_task_completed(future: Future, task_id: str):
+    if future.exception() is None:
+        print_ts(f"completed")
+    else:
+        print_ts(f"completed with error")
+
+
+def dispatch_work(work: list[tuple[str, Callable]]):
+    with ThreadPoolExecutor(max_workers=4) as executor:
+        for task_id, func in work:
+            future = executor.submit(func)
+            future.add_done_callback(
+                functools.partial(print_task_completed, task_id=task_id)
+            )
+            # future.add_done_callback(
+            #     lambda fut: print_task_completed(fut, task_id)
+            # )
+
+
+def some_work(arg):
+    time.sleep(0.0)  # simulate work
+    print_ts(arg)
+
+
+def main():
+    work = [
+        ("task_a", functools.partial(some_work, "A")),
+        ("task_b", functools.partial(some_work, "B")),
+        ("task_c", functools.partial(some_work, "C")),
+        ("task_d", functools.partial(some_work, "D")),
+    ]
+    dispatch_work(work)
+    print("all done")
+
+
+if __name__ == '__main__':
+    main()