f-string

In Python 3.6, you can use f-strings like: >>> date = datetime.date(1991, 10, 12) >>> f'{date} was on a {date:%A}' '1991-10-12 was on a Saturday' I want to overload the method receiving the '%A' above. Can it be done? For example, if I wanted to write a dumb wrapper around datetime , I might expect this overloading to look something like: class MyDatetime: def __init__(self, my_datetime, some_other_value): self.dt = my_datetime self.some_other_value = some_other_value def __fstr__(self, format_str): return ( self.dt.strftime(format_str) + 'some other string' + str(self.some_other_value ) Yes ,

One of the features of Python 3.6 are formatted strings. This SO question (String with 'f' prefix in python-3.6) is asking about the internals of formatted string literals, but I don't understand the exact use case of formatted string literals. In which situations should I use this feature? Isn't explicit better than implicit? xmcp Simple is better than complex. So here we have formatted string. It gives the simplicity to the string formatting, while keeping the code explicit (comprared to other string formatting mechanisms). title = 'Mr.' name = 'Tom' count = 3 # This is explicit but complex

Previously you would use gettext as following: _('Hey {},').format(username) but what about new Python's f-string? f'Hey {username}' 'Hey {},' is contained in your translation dictionary as is. If you use f'Hey {username},' , that creates another string, which won't be translated. In that case, the format method remains the only one useable. Preface I know this question is quite old and already has a very legitimate answer but I’m going to be bold and give my answer to this as I landed here while searching, and I am a fan of using f-strings myself and don’t want to lose out on its use but also

The new Python 3.6 f-strings seem like a huge jump in string usability to me, and I would love to jump in and adopt them whole heartedly on new projects which might be running on older interpreters. 2.7, 3.3-3.5 support would be great but at the very least I would like to use these in Python 3.5 code bases. How can I import 3.6's formatted string literals for use by older interpreters? I understand that formatted string literals like f"Foo is {age} {units} old" are not breaking changes, so would not be included in a from __future__ import ... call. But the change is not back-ported (AFAIK) I