From 46da504eba4abcef200d602abf242731ce9ffeeb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Fri, 30 Aug 2024 11:42:40 +0300
Subject: [PATCH] add map codealong dump

---
 slides/map_example_codealong.py | 40 +++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 slides/map_example_codealong.py

diff --git a/slides/map_example_codealong.py b/slides/map_example_codealong.py
new file mode 100644
index 0000000..b07d6a4
--- /dev/null
+++ b/slides/map_example_codealong.py
@@ -0,0 +1,40 @@
+# Computer scientists love the Fibonacci sequence
+# [https://en.wikipedia.org/wiki/Fibonacci_sequence], possibly
+# described by Acharya Pingala in छन्दःशास्त्र (Chhandaḥśāstra).
+#
+# The basic definition is that the next item in the sequence
+# if the sum of the two preceding items, and the two initial
+# items and 0 and 1.
+#
+# We end up with [0, 1, 1, 2, 3, 5, 8, 13, ...]
+
+def fibbo(n):
+    match n:
+        case 0 | 1:
+            return n
+        case _:
+            return fibbo(n-1) + fibbo(n-2)
+
+# For example: the first few items in the sequence:
+for n in range(36):
+    print(n, fibbo(n))
+
+# A (nowadays) less commonly used way to construct the mapping
+# from n to fibbo(n) is to use the map function.
+# map returns a generator, and we call list to collect the numbers:
+sequence = list(map(fibbo, range(36)))
+print(sequence)
+
+# To split the work between multiple Python processes, we can
+# use the multiprocessing module:
+import multiprocessing
+
+pool = multiprocessing.Pool()
+sequence = pool.map(fibbo, range(36))
+print(sequence)
+
+# We may use 'with' to clean up the pool after we're done with
+# the workers:
+with multiprocessing.Pool(10) as pool:
+    sequence = pool.map(fibbo, range(36))
+print(sequence)