Joshua Merriman Joshua Merriman - 7 months ago 55
Python Question

A good way to make long strings wrap to newline in Python? (3.x)

In my project, I have a bunch of strings that are read in from a file. Most of them, when printed in the command console, exceed 80 characters in length and wrap around, looking ugly.

I want to be able to have Python read the string, then test if it is over 75 characters in length. If it is, then split the string up into multiple strings, then print one after the other on a new line.
I also want it to be smart, not cutting off full words. i.e.

"The quick brown <newline> fox..."
instead of
"the quick bro<newline>wn fox..."
.

I've tried modifying similar code that truncates the string after a set length, but just trashes the string instead of putting it in a new line.

What are some methods I could use to accomplish this?

Answer

You could use textwrap module:

>>> import textwrap
>>> strs = "In my project, I have a bunch of strings that are read in from a file. Most of them, when printed in the command console, exceed 80 characters in length and wrap around, looking ugly."
>>> print(textwrap.fill(strs, 20))
In my project, I
have a bunch of
strings that are
read in from a file.
Most of them, when
printed in the
command console,
exceed 80 characters
in length and wrap
around, looking
ugly.

help on textwrap.fill

>>> textwrap.fill?

Definition: textwrap.fill(text, width=70, **kwargs)
Docstring:
Fill a single paragraph of text, returning a new string.

Reformat the single paragraph in 'text' to fit in lines of no more
than 'width' columns, and return a new string containing the entire
wrapped paragraph.  As with wrap(), tabs are expanded and other
whitespace characters converted to space.  See TextWrapper class for
available keyword args to customize wrapping behaviour.

Use regex if you don't want to merge a line into another line:

import re
strs = """In my project, I have a bunch of strings that are.
Read in from a file.
Most of them, when printed in the command console, exceed 80.
Characters in length and wrap around, looking ugly."""
print('\n'.join(line.strip() for line in re.findall(r'.{1,40}(?:\s+|$)', strs)))
"""
Reading a single line at once:
for x in strs.splitlines():
    print '\n'.join(line.strip() for line in re.findall(r'.{1,40}(?:\s+|$)', x))
"""

output:

In my project, I have a bunch of strings
that are.
Read in from a file.
Most of them, when printed in the
command console, exceed 80.
Characters in length and wrap around,
looking ugly.