Creating formatted output using picture strings

[Tim Chase]

python at bdurham.com wrote:
> Original poster here.
> 
> Thank you all for your ideas. I certainly learned some great techniques
> by studying everyone's solutions!!

Thanks for the positive feedback -- it's something most folks 
like to hear when they try to assist and such thanks appears too 
rarely on the list.

> Here's the solution I came up with myself. Its not as sexy as some of
> the posted solutions, but it does have the advantage of not failing when
> the number of input chars <> the number of placeholders in the pic
> string. 
 >
> Any feedback on what follows would be appreciated.
[snip]
> # test cases
> print picture("123456789", "(@@@)-@@-(@@@)[@]")
> print picture("123456789ABC", "(@@@)-@@-(@@@)[@]")
> print picture("1234", "(@@@)-@@-(@@@)[@]")
> print picture("123456789", "(@@@)-@@-(@@@)")
> print picture("123456789", "(@@@)-@@-(@@@)[@][@@@@@]")
> 	

You don't give the expected output for these test cases, so it's 
hard to tell whether you want to pad-left or pad-right.

Riffing on MRAB's lovely solution, you can do something like

   def picture(
       s, pic,
       placeholder='@',
       padding=' ',
       pad_left=True
       ):
     assert placeholder != '%'
     s = str(s)
     expected = pic.count(placeholder)
     if len(s) > expected:
       s = s[:expected]
     if len(s) < expected:
       if pad_left:
         s = s.rjust(expected, padding)
       else:
         s = s.ljust(expected, padding)
     return pic.replace(
       '%', '%%').replace(
       placeholder, '%s') % tuple(s)

print picture("123456789", "(@@@)-@@-(@@@)[@]", pad_left=False)
print picture("123456789ABC", "(@@@)-@@-(@@@)[@]", pad_left=False)
print picture("1234", "(@@@)-@@-(@@@)[@]", pad_left=False)
print picture("123456789", "(@@@)-@@-(@@@)", pad_left=False)
print picture("123456789", "(@@@)-@@-(@@@)[@][@@@@@]", 
pad_left=False)

That way you can specify your placeholder, your padding 
character, and whether you want it to pad to the left or right.

-tkc