Writing/parsing a fixed width file using Python

Question

I\'m a newbie to Python and I\'m looking at using it to write some hairy EDI stuff that our supplier requires.

Basically they need an 80-character fixed width text f

Answer 1

You don't need to assign to slices, just build the string using % formatting.

An example with a fixed format for 3 data items:

>>> fmt="%4s%10s%10s"
>>> fmt % (1,"ONE",2)
'   1       ONE         2'
>>> 

Same thing, field width supplied with the data:

>>> fmt2 = "%*s%*s%*s"
>>> fmt2 % (4,1, 10,"ONE", 10,2)
'   1       ONE         2'
>>> 

Separating data and field widths, and using zip() and str.join() tricks:

>>> widths=(4,10,10)
>>> items=(1,"ONE",2)
>>> "".join("%*s" % i for i in zip(widths, items))
'   1       ONE         2'
>>>