On 5/26/2021 7:07 AM, Chris Angelico wrote:
Either way, it would be a string. The difference is that string
literals can be placed adjacent to each other:
"{1}" f' - {1+2=} - ' '{2}'
'{1} - 1+2=3 - {2}'
Which goes to show, btw, that an f-string is still a literal, even
though it's not a constant.
Again unrelated to the topic at hand, but I think it's interesting to
see what's going on behind the scenes:
>>> dis.dis("'{1}' f' - {1+2=} - ' '{2}'")
1 0 LOAD_CONST 0 ('{1} - 1+2=')
2 LOAD_CONST 1 (3)
4 FORMAT_VALUE 2 (repr)
6 LOAD_CONST 2 (' - {2}')
8 BUILD_STRING 3
10 RETURN_VALUE
The 1+2 expression is replaced by 3 by some optimizer step. Regular
strings and the literal part of f-strings are merged by the f-string
"compiler".
I keep forgetting about this behavior. I usually start doubling the
braces, but this auto-concatenation is probably a better idea.
Eric
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