sprintf like functionality in Python

Question

I would like to create a string buffer to do lots of processing, format and finally write the buffer in a text file using a C-style sprintf functionality in Pyt

Answer 1

Two approaches are to write to a string buffer or to write lines to a list and join them later. I think the StringIO approach is more pythonic, but didn't work before Python 2.6.

from io import StringIO

with StringIO() as s:
   print("Hello", file=s)
   print("Goodbye", file=s)
   # And later...
   with open('myfile', 'w') as f:
       f.write(s.getvalue())

You can also use these without a ContextMananger (s = StringIO()). Currently, I'm using a context manager class with a print function. This fragment might be useful to be able to insert debugging or odd paging requirements:

class Report:
    ... usual init/enter/exit
    def print(self, *args, **kwargs):
        with StringIO() as s:
            print(*args, **kwargs, file=s)
            out = s.getvalue()
        ... stuff with out

with Report() as r:
   r.print(f"This is {datetime.date.today()}!", 'Yikes!', end=':')