Add Iterate First N Items From Enumerable as a Python TIL

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

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+# 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.