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pythonf-string

Can I use a symbol other than the equal sign in self-documenting f-strings

Self-documenting f-strings in Python allow you to write a print statement like this:

print(f"{result=}")

This works fine, but the = sign is not just used to tell Python you want a self-documenting f-string...it is also the symbol that gets formatted into the output. Is there any way to get Python to use the : character instead of the = character in the output of self-documenting f-strings, maybe something like this:

print(f"{result:}")
Solution

  • No, it's not currently possible to change the way self-documenting f-strings are formatted. The documentation explains:

    When the equal sign '=' is provided, the output will have the expression text, the '=' and the evaluated value. Spaces after the opening brace '{', within the expression and after the '=' are all retained in the output. By default, the '=' causes the repr() of the expression to be provided, unless there is a format specified. When a format is specified it defaults to the str() of the expression unless a conversion '!r' is declared.

    As you can see, the = in the output is fixed by the specification.

    I don't know the process of requesting changes to the language, but this seems like it would be a reasonable request. But for now you'll have to format it manually, like you've had to do before 3.12.