Python3.2 Str.format value repetition

Question

I'm generating specifically formated input files for a program, and using a small python tkinter GUI frontend to do so. The old code made use of fortran format statements. Unless there's already a direct conversion set of functions for python (which I haven't found), I figured python's formatting would do the job. In general it can, but I can't find a way to have repetition of a certain value:

For example, in fortran:

FORMAT (2A1, I3, **12I5**, F8.3, A7). The "12I5" statement translates to 12 integer values of width 5.

I know I could textually have 12 items in my format call (e.g: ...{0:5d}, {1:5d}, {2:5d}....), but I was wondering if there's a way to have a simplified form like the above fortran example.

Is there something I missed, or is this not possible and I must explicitly write out every item in the format?

-Cheers, Chris.

edit Here is a more clear example of what I'm currently doing:

>>> ---tester = ["M", "T", 1111, 2222, 234.23456, "testing"]    
>>> ---fmt = "{0:1}{1:1}, {2:3d}, {3:5d}, {4:8.3F}, {5:>7}"    
>>> ---print(fmt.format(*tester))    
MT,  13,  1234,  234.235, testing

I'd like to be able to

>>> ---tester = ["M", "T", 1111, **2222, 3333, 4444**, 234.23456, "testing"]    
>>> ---fmt = "{0:1}{1:1}, {2:3d}, **3*{3:5d}**, {4:8.3F}, {5:>7}"    
>>> ---print(fmt.format(*tester))       

Answer 1

As ninjagecko suggested, you want to construct your format string in pieces.

Using implicit field numbering as I have done helps simplify this, although it isn't strictly necessary (explicit numbering just gets a little more verbose making sure the numbers line up). Mixing old- and new-style string formatting also means we can skip some tedious escaping of special characters.

subfmt = ", ".join(["{:5d}"]*3)
fmt = "{:1}{:1}, {:3d}, %s, {:8.3F}, {:>7}" % subfmt
tester = ["M", "T", 1111, 2222, 3333, 4444, 234.23456, "testing"]

>>> print(fmt)
{:1}{:1}, {:3d}, {:5d}, {:5d}, {:5d}, {:8.3F}, {:>7}
>>> print(fmt.format(*tester))
MT, 1111,  2222,  3333,  4444,  234.235, testing

Answer 2

You could generate part of your format string like so (adapt as you see fit):

>>> ','.join(['%s']*5)
'%s,%s,%s,%s,%s'

>>> ','.join(['%i']*5) % (1,2,3,4,5)
'1,2,3,4,5'

or even like '%i '*10 (more terse, if you don't mind an extra separator value at the end)

edit: the above is deprecated, and the original poster would like an explicit example, so here is an explicit example with str.format ( http://docs.python.org/library/stdtypes.html#str.format ) using the format specified in http://docs.python.org/library/string.html#formatstrings . Note that you can do much more complicated things than this demo, such as using nice keyword arguments or even object attributes. See docs.

tester = ["M", "T", 1111, 2222, 3333, 4444, 234.23456, "testing"]
fmt = "{}{}, {:3d}, " + 3*"{:5d}, " + "{:8.3F}, {:>7}"
fmt.format(*tester)

result:

'MT, 1111,  2222,  3333,  4444,  234.235, testing'

(edit2: with apologies to ncoghlan; I did not see his new answer before updating)