[Python-3000] String formatting: Conversion specifiers

Bill Janssen janssen at parc.com
Tue Jun 6 18:29:27 CEST 2006

> Here is a list of the conversion types that are currently supported by 
> the % operator. First thing you notice is an eerie similarity between 
> this and the documentation for 'sprintf'. :)

Yes.  This is (or was) a significant advantage to the system.  Many
people already had mastered the C/C++ printf system of specifiers, and
could use Python's with no mental upgrades.  Is that no longer thought
to be an advantage?

> So there's no need to tell the system 'this is a float' 
> or 'this is an integer'.

Except that the type specifier can affect the interpretation of the
rest of the format string.  For example, %.3f means to print three
fractional digits.

> The only way I could see this being useful is 
> if you had a type and wanted it to print out as some different type - 
> but is that really the proper role of the string formatter?

Isn't that exactly what the string formatter does?  I've got a binary
value and want to express it as a different type, a string?  Type
punning at the low levels is often a useful debugging tool.


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