feat: key function for built-in max() function

Author: DahlitzFlorian

ebook/chapters/standard_lib_chapters/dealing_builtins.tex

@@ -40,3 +40,18 @@ \subsection{Capture Output}
 In this case we save the output to \lstinline{help.txt}.
 
 Last but not least we are redirecting the output to stderr.
+
+
+\subsection{max() Key Function}
+
+As many other built-in functions, the \lstinline{max()} function allows you to specify a key function.
+This allows you to (for instance) have a list of strings of integers and select the largest number of them.
+Without specifying \lstinline{key}, the wrong element is being selected.
+
+\lstinputlisting[caption=max\_int\_in\_list\_of\_str.py]{../standard_lib/max_int_in_list_of_str.py}
+
+\begin{lstlisting}[caption=Output of max\_int\_in\_list\_of\_str.py]
+    $ python max_int_in_list_of_str.py
+    9
+    222
+\end{lstlisting}

ebook/python-snippets.epub

@@ -32,6 +32,7 @@ A collection of useful snippets using only the standard library.
 | human_readable_bytecode | Print the bytecode representations in a human readble format |
 | keep_metadata_on_decorator_usage | Keep functions metadata after decoration |
 | list_unpacking | Unpacking a list using the `*` operator |
+| max_int_in_list_of_str | Get the largest number from a list of strings |
 | merge_arbitrary_number_of_dicts | The most pythonic way to merge an arbitrary number of dicts |
 | MicroWebServer | A lightweight micro web server |
 | multi_dict_with_init | Provide a multi dict with default value using `defaultdict` |

ebook/python-snippets.mobi

@@ -0,0 +1,7 @@
+numbers = ["9", "44", "8", "222"]
+
+max_string = max(numbers)
+print(f"Max string: {max_string}")
+
+max_number = max(numbers, key=int)
+print(f"Max number: {max_number}")