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Groups > comp.lang.python > #4867

Re: string formatting

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On 5/6/2011 3:22 PM, harrismh777 wrote:

> I don't really like the old style, not because there is anything wrong
> with it,

There is in that it special cases tuples. For instance, a message 
function like

def emsg(x):
   print("The following object caused a proplem: %s" % x)

raises "TypeError: not all arguments converted during string formatting"
if x is a tuple with other than 1 member and extracts x[0] if there is 
just one. Neither is the desired behavior. That has been a problem (and 
sometimes a debugging puzzle) in real code One has to remember to write 
something like

def emsg(x):
   if isinstance(x,tuple):
     x = (x,)
   print(The following object caused a proplem: %s" % x)

Guido sees that his original design is a bit of a bug trap, which is one 
reason he wanted to replace it.

-- 
Terry Jan Reedy

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string formatting Jabba Laci <jabba.laci@gmail.com> - 2011-05-06 03:18 -0400
  Re: string formatting Web Dreamer <webdreamer@nospam.fr> - 2011-05-06 10:00 +0200
    Re: string formatting Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-06 08:46 +0000
      Re: string formatting Chris Rebert <clp2@rebertia.com> - 2011-05-06 02:23 -0700
        Re: string formatting Web Dreamer <webdreamer@nospam.fr> - 2011-05-06 14:10 +0200
          Re: string formatting nn <pruebauno@latinmail.com> - 2011-05-06 06:06 -0700
          Re: string formatting Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-06 14:33 +0000
          Re: string formatting Web Dreamer <webdreamer@nospam.fr> - 2011-05-10 16:15 +0200
            Re: string formatting Chris Angelico <rosuav@gmail.com> - 2011-05-11 00:43 +1000
        Re: string formatting Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-06 14:24 +0000
          Re: string formatting harrismh777 <harrismh777@charter.net> - 2011-05-06 14:22 -0500
            Re: string formatting harrismh777 <harrismh777@charter.net> - 2011-05-06 14:39 -0500
              Re: string formatting Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-06 13:54 -0600
              Re: string formatting Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-07 02:30 +0000
              Re: string formatting alex23 <wuwei23@gmail.com> - 2011-05-08 22:47 -0700
            Re: string formatting Neil Cerutti <neilc@norwich.edu> - 2011-05-06 19:54 +0000
            Re: string formatting Terry Reedy <tjreedy@udel.edu> - 2011-05-06 16:54 -0400
            Re: string formatting Chris Angelico <rosuav@gmail.com> - 2011-05-07 10:09 +1000
            Re: string formatting Terry Reedy <tjreedy@udel.edu> - 2011-05-07 03:55 -0400
  Re: string formatting Raymond Hettinger <python@rcn.com> - 2011-05-10 10:20 -0700

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