在Python中将长字符串换行换行的好方法是什么？

Question

在我的项目中,我有一堆从文件中读入的字符串.在命令控制台中打印时,大多数都超过80个字符并且环绕,看起来很难看.

我希望能够让Python读取字符串,然后测试它是否超过75个字符.如果是,则将字符串拆分为多个字符串,然后在新行上逐个打印.我也希望它聪明,不要切断全文.即"The quick brown <newline> fox..."代替"the quick bro<newline>wn fox...".

我已经尝试修改类似的代码,在设定的长度后截断字符串,但只是删除字符串而不是将它放在一个新行中.

我可以用什么方法来实现这个目标？

Answer 1

你可以使用textwrap模块:

>>> 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.

帮助上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.

使用regex,如果你不想线合并到另一条线路:

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))

输出:

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.

Answer 2

这就是textwrap模块的用途.试试textwrap.fill(some_string, width=75).

Answer 3

这类似于 Ashwini 的回答，但不使用re：

lim=75
for s in input_string.split("\n"):
    if s == "": print
    w=0 
    l = []
    for d in s.split():
        if w + len(d) + 1 <= lim:
            l.append(d)
            w += len(d) + 1 
        else:
            print " ".join(l)
            l = [d] 
            w = len(d)
    if (len(l)): print " ".join(l)

当输入是您的问题时输出：

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...".