I hope they also add a way to evaluate the f-string bindings at runtime. I keep running into places where I want to define f{foo} but have foo not be bound until the f-string is used at runtime. You can’t do that.
I keep running into places where I want to define f{foo} but have foo not be bound until the f-string is used at runtime. You can’t do that.
Yeah, as you mentioned there are some ugly work arounds – you can kind of use a lambda and partial as another example (not that I would necessarily recommend it though):
>>> thing = lambda _: f"I like {x} {y}"
>>> t = functools.partial(thing, None)
>>> x = "pickles"
>>> y = "on saturdays"
>>> t()
'I like pickles on saturdays'
>>> y = "on sundays"
>>> t()
'I like pickles on sundays'
str.format() is not a workaround, f-strings do exactly what str.format() is doing, it’s just a syntactic sugar for that. It worked before and working since then to just construct a format string and use it with str.format().
You are wrong. str.format() has very different semantic and inner working than f-strings. str.format format string are not even reusable for f-string. See https://docs.python.org/3/library/string.html#formatstrings. You can’t even eval arbitrary python with str.format, only access attributes or index or the given parameters.
I might have worded poorly, but I’m not wrong. What I meant was that after evaluating f-strings, they work the same way, which I thought not worth mentioning, because obviously evaluation is the whole point of f-strings over str.format().
I hope they also add a way to evaluate the f-string bindings at runtime. I keep running into places where I want to define
f{foo}but havefoonot be bound until the f-string is used at runtime. You can’t do that.There’s a bunch of workarounds. Using
str.format()is probably the best, but the languageformat()understands is different from f-string’s templates. You can get real f-strings but only by doingevalorinspecthacks, discussion here: https://stackoverflow.com/questions/42497625/how-to-postpone-defer-the-evaluation-of-f-stringsYeah, as you mentioned there are some ugly work arounds – you can kind of use a lambda and partial as another example (not that I would necessarily recommend it though):
str.format() is not a workaround, f-strings do exactly what str.format() is doing, it’s just a syntactic sugar for that. It worked before and working since then to just construct a format string and use it with str.format().
You are wrong.
str.format()has very different semantic and inner working than f-strings.str.formatformat string are not even reusable for f-string. See https://docs.python.org/3/library/string.html#formatstrings. You can’t even eval arbitrary python withstr.format, only access attributes or index or the given parameters.I might have worded poorly, but I’m not wrong. What I meant was that after evaluating f-strings, they work the same way, which I thought not worth mentioning, because obviously evaluation is the whole point of f-strings over str.format().