On Fri, Sep 18, 2020 at 6:19 AM Christopher Barker <[email protected]> wrote: > > I like the idea of an scans like ability, but I"m afraid the existing format > language is poorly suited to that. > > It's simply no designed to be a two-way street: > > * ANYTHING can be stringified in Python -- so there is no defined way to turn > a string back into a particular type. > > OK, so we restrict ourselves to builtins -- how would you reverse this: > > In [17]: x, y, z = 23, 45, 67 > > In [18]: f"{x}{y}{z}" > Out[18]: '234567' > > so we require a type specifier, but similar problem: > > In [19]: f"{x:d}{y:d}{z:d}" > Out[19]: '234567' > > So we require a field size specifier: > > In [20]: f"{x:2d}{y:2d}{z:2d}" > Out[20]: '234567' > > OK, I guess that is clearly defined. but we've now limited ourselves to a > very small subset of the formatting language -- maybe it's not the right > language for the job? >
And that's why the directives are NOT just a pure mirroring of format string directives. Look at C's scanf and printf functions - they correspond in many ways, but they differ in order to be useful. The point isn't to reverse format(), the point is to have a useful and practical string parser that assigns directly to variables. Also, PEP 622. ChrisA _______________________________________________ Python-ideas mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/[email protected]/message/A67UEO6FONE6H5PTYCJCP5B5AXBMZSD3/ Code of Conduct: http://python.org/psf/codeofconduct/
