Add Sort Normalized Version Of Data as a Python TIL

README.md

@@ -10,7 +10,7 @@ working across different projects via [VisualMode](https://www.visualmode.dev/).
 
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-_1779 TILs and counting..._
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 See some of the other learning resources I work on:
 
@@ -1070,6 +1070,7 @@ If you've learned something here, support my efforts writing daily TILs by
 - [Parse Relative Time To datetime Object](python/parse-relative-time-to-datetime-object.md)
 - [Skip Specific Pytest Test Cases](python/skip-specific-pytest-test-cases.md)
 - [Sort A List Of Dataclass Instances](python/sort-a-list-of-dataclass-instances.md)
+- [Sort Normalized Version Of Data](python/sort-normalized-version-of-data.md)
 - [Start The Debugger When A Test Errors](python/start-the-debugger-when-a-test-errors.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/sort-normalized-version-of-data.md

@@ -0,0 +1,33 @@
+# Sort Normalized Version Of Data
+
+Let's say I have a list of names that I want to sort. However, because of
+inconsistency in how the data was entered, sometimes those names are capitalized
+and other times they are not. Using
+[`methodcaller`](https://docs.python.org/3/library/operator.html#operator.methodcaller),
+I can normalize the sorting `key` used when comparing list items.
+
+First, let's look at calling `sorted` with the list and no `key`:
+
+```python
+>>> sorted(["butler", "Jemisin", "le guin", "Erdrich"])
+['Erdrich', 'Jemisin', 'butler', 'le guin']
+```
+
+`butler` which starts with a `b` gets moved to the 3rd position because it is
+lowercase.
+
+To sort this list using a normalized comparison, we will use `methodcaller` to
+create a callable out of `lower` which is then passed as the sort `key`:
+
+```python
+>>> from operator import methodcaller
+>>> sorted(["butler", "Jemisin", "le guin", "Erdrich"], key=methodcaller("lower"))
+['butler', 'Erdrich', 'Jemisin', 'le guin']
+```
+
+That's the sort order I was originally hoping for.
+
+What `methodcaller` is doing is creating a callable function that will invoke
+`lower` with each string instance as the target. Conceptually similar to
+`"Erdrich".lower()` or even `getattr("Erdrich", "lower")()` (notice this needs
+to be immediately invoked).