partial string formatting

Asked 2012-07-01T17:00:01.463

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Is it possible to do partial string formatting with the advanced string formatting methods, similar to the string template safe_substitute() function?

For example:

s = '{foo} {bar}'
s.format(foo='FOO') #Problem: raises KeyError 'bar'

python string-formatting

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If you define your own Formatter which overrides the get_value method, you could use that to map undefined field names to whatever you wanted:

http://docs.python.org/library/string.html#string.Formatter.get_value

For instance, you could map bar to "{bar}" if bar isn't in the kwargs.

However, that requires using the format() method of your Formatter object, not the string's format() method.

answered 2012-07-01T17:06:33.093

partial string formatting

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