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From: Ervin =?utf-8?Q?Heged=C3=BCs?= <airween@gmail.com>
Newsgroups: comp.lang.python
Subject: Re: String format - resolve placeholders names
Date: Fri, 20 Nov 2015 16:53:00 +0100
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Xref: csiph.com comp.lang.python:99157

Hello Chris,

On Sat, Nov 21, 2015 at 02:06:11AM +1100, Chris Angelico wrote:
> On Sat, Nov 21, 2015 at 1:52 AM, Ervin Hegedüs <airween@gmail.com> wrote:
> > Python has a good string formatter, eg. I can do this:
> >
> > s = "{who} likes {what}"
> > d = {'who': "Adam", 'what': "ants"}
> > s.format(**d)

...

> > But is there any other (direct) way, which keywords exists in
> > string?
> 
> I think what you're asking for can be done using format_map with a
> custom mapping object:
> 
> >>> class IdentiMap:
> ...     def __init__(self):
> ...         self.keys = []
> ...     def __getitem__(self, key):
> ...         self.keys.append(key)
> ...
> >>> m = IdentiMap()
> >>> "{who} likes {what}".format_map(m)
> 'None likes None'
> >>> m.keys
> ['who', 'what']
> 
> Does that help?

absolutely, many thanks again!


a.