Add Iterate First N Items From Enumerable as a Python TIL

README.md

@@ -10,7 +10,7 @@ working across different projects via [VisualMode](https://www.visualmode.dev/).
 
 For a steady stream of TILs, [sign up for my newsletter](https://visualmode.kit.com/newsletter).
 
-_1737 TILs and counting..._
+_1738 TILs and counting..._
 
 See some of the other learning resources I work on:
 
@@ -1034,6 +1034,7 @@ If you've learned something here, support my efforts writing daily TILs by
 - [Break Debugger On First Line Of Program](python/break-debugger-on-first-line-of-program.md)
 - [Create A Dummy DataFrame In Pandas](python/create-a-dummy-dataframe-in-pandas.md)
 - [Dunder Methods](python/dunder-methods.md)
+- [Iterate First N Items From Enumerable](python/iterate-first-n-items-from-enumerable.md)
 - [Override The Boolean Context Of A Class](python/override-the-boolean-context-of-a-class.md)
 - [Store And Access Immutable Data In A Tuple](python/store-and-access-immutable-data-in-a-tuple.md)
 - [Test A Function With Pytest](python/test-a-function-with-pytest.md)

python/iterate-first-n-items-from-enumerable.md

@@ -0,0 +1,27 @@
+# Iterate First N Items From Enumerable
+
+As I'm working through the 2nd chapter of [Build a Large Language Model (from
+scratch)](https://still.visualmode.dev/blogmarks/227), I came across a code
+example processing a dictionary of words. This example used a for loop to print
+out each dictionary entry until an index of 50 was reached on then it did a
+`break`.
+
+This struck me as an odd way to grab and process N items from a list. I did some
+searching and found `itertools` which provides
+[`islice`](https://docs.python.org/3/library/itertools.html#itertools.islice).
+
+```python
+from itertools import islice
+
+# preprocess words from a file into a word list
+all_words = ... # not shown here
+
+vocab = {token: integer for integer, token in enumerate(all_words)}
+for item in islice(enumerate(vocab.items()), 50):
+    print(item)
+```
+
+The `islice` function is a better approach because the intention (to grab the
+first 50 things) is encoded in the function call rather than buried in a loop
+body. It also has equivalent memory efficiency to the original example because
+it lazily processes the list of `vocab` items.