在Python中，有没有一种方法可以插入换行符并在字符串的每68个字符之间插入空格？

Question

I am reading in descriptions and converting them to strings in python. Due to outdated standards, the length of each line must be no more than 80 characters. The first 12 is a ';' followed by 11 spaces and the last 68 should be the string.

We have strings of over 300 characters, so I need to insert a '\\n;' and 11 spaces every 68 characters. We also have strings that already contain a '\\n' that needs to be maintained. Also it would be prefered if words weren't broken up.

Is this possible in python?

I was attempting to do it like this but was having no luck.

def badChars(stri):
    p=0
    if len(stri) > 68:
        for i in range(0, len(stri)):
            if stri[i] == "\\" and stri[i+1] == "n":
                p=-1
            if p > 68:
                stri[i] = stri[i] + "\n;                 "
                p=-1
            p=p+1  

I need the words to stay intact and the current \\n to be maintained.

Answer 1

You can wrap lines using the textwrap module ; you can specify indentation to be used too:

import textwrap

indentation = ';' + ' ' * 11
result = textwrap.fill(
    input_text, width=80,
    initial_indent=indentation, subsequent_indent=indentation)

If you need to maintain existing newlines, split on those first, apply wrapping to each line, then rejoin with newlines:

indentation = ';' + ' ' * 11
params = {
    'width': 80,
    'initial_indent': indentation,
    'subsequent_indent': indentation
}
result = '\n'.join([textwrap.fill(line, **params)
                    for line in input_text.splitlines()])

The str.splitlines() method is the easiest method to split lines by line separators.

Demo:

>>> import textwrap
>>> input_text = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.'
>>> indentation = ';' + ' ' * 11
>>> result = textwrap.fill(
...     input_text, width=80,
...     initial_indent=indentation, subsequent_indent=indentation)
>>> print result
;           Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do
;           eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim
;           ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut
;           aliquip ex ea commodo consequat. Duis aute irure dolor in
;           reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla
;           pariatur. Excepteur sint occaecat cupidatat non proident, sunt in
;           culpa qui officia deserunt mollit anim id est laborum.
>>>
>>> # produce a sample with newlines by inserting these around 170 characters
... 
>>> input_text = textwrap.fill(input_text, width=170)
>>> print input_text
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud
exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla
pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
>>> params = {
...     'width': 80,
...     'initial_indent': indentation,
...     'subsequent_indent': indentation
... }
>>> result = '\n'.join([textwrap.fill(line, **params)
...                     for line in input_text.splitlines()])
>>> print result
;           Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do
;           eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim
;           ad minim veniam, quis nostrud
;           exercitation ullamco laboris nisi ut aliquip ex ea commodo
;           consequat. Duis aute irure dolor in reprehenderit in voluptate velit
;           esse cillum dolore eu fugiat nulla
;           pariatur. Excepteur sint occaecat cupidatat non proident, sunt in
;           culpa qui officia deserunt mollit anim id est laborum.

The width specified includes the indentation. Note that it'll use whitespace to wrap lines at whole words. See the module documentation for more options to control how lines are wrapped.