在 Python 中包装多行字符串（保留现有的换行符）？

Question

考虑这个例子：

import textwrap
import pprint

mystr=r"""
First line.
Second line.
The third line is a very long line, which I would like to somehow wrap; wrap at 80 characters - or less, or more! ... can it really be done ??"""

pprint.pprint(textwrap.wrap(mystr,80))

字符串 mystr 已经是多行字符串，因为它包含换行符；但是，如果我运行这个脚本，我会得到输出：

[' First line. Second line. The third line is a very long line, which I would like',
 'to somehow wrap; wrap at 80 characters - or less, or more! ... can it really be',
 'done ??']

... 这意味着 textwrap.wrap 首先 "joined" 多行字符串（即删除其中现有的换行符），然后才将其换行（即按给定数字拆分它个字符）。

如何换行多行字符串以保留换行符？也就是说，在这种情况下，预期输出将是：

['First line.', 
 'Second line.', 
 'The third line is a very long line, which I would like to somehow wrap; wrap at',
 '80 characters - or less, or more! ... can it really be done ??']

编辑；感谢@u_mulder 的评论，我试过：

textwrap.wrap(mystr,80,replace_whitespace=False)

然后我得到：

['\nFirst line.\nSecond line.\nThe third line is a very long line, which I would like',
 'to somehow wrap; wrap at 80 characters - or less, or more! ... can it really be',
 'done ??']

换行符似乎被保留，但作为 "inline" 个字符；所以这里的第一个元素本身就是一个多行字符串——所以它不是我所要求的，每一行都是一个数组元素。

Answer 1

拆分后把换行符加回来:

import textwrap
import pprint
import itertools

mystr=r"""
First line.
Second line.
The third line is a very long line, which I would like to somehow wrap; wrap at 80 characters - or less, or more! ... can it really be done ??"""

wrapper = textwrap.TextWrapper(width = 80)
mylist = [wrapper.wrap(i) for i in mystr.split('\n') if i != '']
mylist = list(itertools.chain.from_iterable(mylist))

pprint.pprint(mylist)

输出：

['First line.',
 'Second line.',
 'The third line is a very long line, which I would like to somehow wrap; wrap at',
 '80 characters - or less, or more! ... can it really be done ??']

Answer 2

好的，我想我找到了做我想做的事的方法，但有点不雅：

import textwrap
import pprint

mystr=r"""
First line.
Second line.
The third line is a very long line, which I would like to somehow wrap; wrap at 80 characters - or less, or more! ... can it really be done ??"""

#pprint.pprint(textwrap.wrap(mystr,80,replace_whitespace=False))

aa=[]
for ix in mystr.splitlines():
  if ix:
    if len(ix)<=80: aa.append(ix)
    else: aa.extend(textwrap.wrap(ix,80))

pprint.pprint(aa)

结果为：

['First line.',
 'Second line.',
 'The third line is a very long line, which I would like to somehow wrap; wrap at',
 '80 characters - or less, or more! ... can it really be done ??']

所以：

第一个元素：'First line.' 最初定义
第二个元素：'Second line.' 也是最初定义的
第三个元素：原来的第三行太长，所以换行到80个字符，第一部分是数组中的第三个元素
第 4 个元素：包含原始第三行换行的第二部分

这就是我想要实现的；请注意，这与数组中第一个元素包含多行的情况非常不同，如 ['\nFirst line.\nSecond line.\nThe third line ....

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