[Python-Dev] PEP 572 and f-strings (original) (raw)

Chris Angelico rosuav at gmail.com
Sat May 12 09:03:22 EDT 2018

On Sat, May 12, 2018 at 9:11 PM, Eric V. Smith <eric at trueblade.com> wrote:

I don't think it matters to its acceptance, but PEP 572 should at least mention that the := syntax means that you cannot use assignment expressions in f-strings.

As I wrote in a python-ideas email, f'{x:=4}' already has a defined meaning (even if no one is using it).

As with lambda functions, you can't write them the simple way. However, you can parenthesize it, and then it works fine.

f"@{(lambda: 42)}@" '@<function at 0x7f09e18c4268>@' f"@{(y := 1)}@" '@1@' y 1

ChrisA

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