Question

I am trying to use textwrap to format an import file that is quite particular in how it is formatted. Basically, it is as follows (line length shortened for simplicity):

abcdef <- Ok line
abcdef 
 ghijk <- Note leading space to indicate wrapped line
 lm

Now, I have got code to work as follows:

wrapper = TextWrapper(width=80, subsequent_indent=' ', break_long_words=True, break_on_hyphens=False)
for l in lines:
  wrapline=wrapper.wrap(l)

This works nearly perfectly, however, the text wrapping code doesn’t do a hard break at the 80 character mark, it tries to be smart and break on a space (at approx 20 chars in).

I have got round this by replacing all spaces in the string list with a unique character (#), wrapping them and then removing the character, but surely there must be a cleaner way?

N.B Any possible answers need to work on Python 2.4 – sorry!

Answer 1

A generator-based version might be a better solution for you, since it wouldn’t need to load the entire string in memory at once:

def hard_wrap(input, width, indent=' '):
   for line in input:
      indent_width = width - len(indent)
      yield line[:width]
      line = line[width:]
      while line:
         yield '\n' + indent + line[:indent_width]
         line = line[indent_width:]

Use it like this:

from StringIO import StringIO # Makes strings look like files

s = """abcdefg
abcdefghijklmnopqrstuvwxyz"""

for line in hard_wrap(StringIO(s), 12):
   print line,

Which prints:

abcdefg
abcdefghijkl 
 mnopqrstuvw 
 xyz