Merge pull request #409 from realpython/python312-preview-f-string

Sample code - Python 3.12 preview f-strings

Author: KateFinegan

python-312/README.md

@@ -14,6 +14,7 @@ You can learn more about Python 3.12's new features in the following Real Python
 
 - [Python 3.12 Preview: Ever Better Error Messages](https://realpython.com/python312-error-messages/)
 - [Python 3.12 Preview: Support For the Linux `perf` Profiler](https://realpython.com/python312-perf-profiler/)
+- [Python 3.12 Preview: More Intuitive and Consistent F-Strings](https://realpython.com/python312-f-strings/)
 
 You'll find examples from all these tutorials in this repository.
 
@@ -117,6 +118,24 @@ $ cat traces_censored.txt | flamegraph.pl --minwidth 10 > flamegraph.svg
 
 See [Support For the Linux `perf` Profiler in Python 3.12](https://realpython.com/python312-perf-profiler/) for more information.
 
+### New F-String Implementation and Syntax Formalization
+
+Once you have 3.12 installed, open any file from the `f-string/` folder. Uncomment the code as needed. [Run the scripts](https://realpython.com/run-python-scripts/) from your command line or execute the code directly in a [REPL](https://realpython.com/python-repl/) session. You'll see the new f-string implementation in action.
+
+For example, go ahead and run the following command:
+
+```console
+$ python backslashes.py
+Hello
+World!
+I
+am
+a
+Pythonista!
+```
+
+In this example, you can see how the new implementation of f-strings allows you to include backslashes in embedded expressions. This wasn't possible with f-strings in earlier versions of Python. 
+
 ## Authors
 
 - **Martin Breuss**, E-mail: [martin@realpython.com](martin@realpython.com)

python-312/f-string/backslashes.py

@@ -0,0 +1,4 @@
+words = ["Hello", "World!", "I", "am", "a", "Pythonista!"]
+
+# Uncomment the following line and run it in Python 3.12
+# print(f"{'\n'.join(words)}")

python-312/f-string/comments.py

@@ -0,0 +1,10 @@
+employee = {
+    "name": "John Doe",
+    "age": 35,
+    "job": "Python Developer",
+}
+
+# Uncomment the following code and run it in Python 3.12
+# f"""Storing employee's data: {
+#     employee['name'].upper() # Always uppercase name before storing
+# }"""

python-312/f-string/nested.py

@@ -0,0 +1,13 @@
+# Uncomment the following code and run it in Python 3.12
+
+# f"{
+#     f"{
+#         f"{
+#             f"{
+#                 f"{
+#                     f"Deeply nested f-string!"
+#                 }"
+#             }"
+#         }"
+#     }"
+# }"

python-312/f-string/quotes.py

@@ -0,0 +1,8 @@
+employee = {
+    "name": "John Doe",
+    "age": 35,
+    "job": "Python Developer",
+}
+
+# Uncomment the following line and run it in Python 3.12
+# f"Employee: {employee["name"]}"