TIL that python3.12 (PEP701) will remove some restrictions on the usage of f-strings, such as, reusing the same quotes as the containing f-string, allowing usage of backslashes and unicode escaped sequences inside f-strings.
Personally I prefer using double quotes " " for all my python strings.
However, before python 3.12, we are not allowed to use the same quotes inside a
f-string:
# before: python 3.10
# bad: can't use the same double quote inside the curly bracket
>>> names = ["Alex", "Bob", "Cat"]
>>> f"This is my name list: {" - ".join(names)}"
File "<stdin>", line 1
f"This is my name list: {" - ".join(names)}"
^
SyntaxError: f-string: expecting '}'
# ok: replace with single quote
>>> f"This is my name list: {' - '.join(names)}"
'This is my name list: Alex - Bob - Cat'
# after: python 3.12
# ok: to use same quote
>>> f"This is my name list: {" - ".join(names)}"
'This is my name list: Alex - Bob - Cat'This also means that, before this changes, f-strings can be nested only if we are using different string quotes, like:
# before: python 3.10
# bad: can't use the same quote
>>> f"{f"{f"{f"{f"{f"{1+1}"}"}"}"}"}"
File "<stdin>", line 1
f"{f"{f"{f"{f"{f"{1+1}"}"}"}"}"}"
^
SyntaxError: f-string: expecting '}'
# ok: must use different quotes
>>> f"""{f'''{f'{f"{1+1}"}'}'''}"""
'2'Now it is possible to write nested f-strings with the same quotes:
# after: python 3.12
# ok: to use same quotes
>>> f"{f"{f"{f"{f"{f"{1+1}"}"}"}"}"}"
'2'Another thing that I like about python 3.12 f-string is that we can use
backlashes and unicode escaped sequences. The following example is taken
from the official PEP changelog:
>>> print(f"This is the playlist: {"\n".join(songs)}")
This is the playlist: Take me back to Eden
Alkaline
Ascensionism
>>> print(f"This is the playlist: {"\N{BLACK HEART SUIT}".join(songs)}")
This is the playlist: Take me back to Eden♥Alkaline♥AscensionismRelated: