在 python 中打印第一段

我有一本书的文本文件，我需要打印每个部分的第一段。我想如果我在 \n\n 和 \n 之间找到文本我就能找到答案。这是我的代码，但它不起作用。你能告诉我我哪里错了吗？

lines = [line.rstrip('\n') for line in open('G:\\aa.txt')]

check = -1
first = 0
last = 0

for i in range(len(lines)):
    if lines[i] == "": 
            if lines[i+1]=="":
                check = 1
                first = i +2
    if i+2< len(lines):
        if lines[i+2] == "" and check == 1:
            last = i+2
while (first < last):
    print(lines[first])
    first = first + 1

我还在 stackoverflow 中找到了一个代码，我也尝试了它，但它只是打印了一个空数组。

f = open("G:\\aa.txt").readlines()
flag=False
for line in f:
        if line.startswith('\n\n'):
            flag=False
        if flag:
            print(line)
        elif line.strip().endswith('\n'):
            flag=True

我在下面分享了这本书的示例部分。

I

地形

人类感兴趣的广阔领域就在我们的门外，但迄今为止却很少被探索。这是动物智力领域。

在研究世界野生动物的各种兴趣中，没有什么能超越对它们的思想、道德以及它们作为心理过程结果而执行的行为的研究。

II

野生动物的气质和个性

我在这里想做的是，找到大写行，并将它们全部放入一个数组中。然后，使用索引方法，我将通过比较我创建的数组的这些元素的索引来找到每个部分的第一段和最后一段。

输出应该是这样的：

人类感兴趣的广阔领域就在我们的门外，但迄今为止却很少被探索。这是动物智力领域。

我在这里想做的是，找到大写行，并将它们全部放入一个数组中。然后，使用索引方法，我将通过比较我创建的数组的这些元素的索引来找到每个部分的第一段和最后一段。

如果您想对可以使用的部分进行分组itertools.groupby使用空行作为分隔符：

from itertools import groupby
with open("in.txt") as f:
    for k, sec in groupby(f,key=lambda x: bool(x.strip())):
        if k:
            print(list(sec))

通过更多 itertools foo，我们可以使用大写标题作为分隔符来获取节：

from itertools import groupby, takewhile

with open("in.txt") as f:
    grps = groupby(f,key=lambda x: x.isupper())
    for k, sec in grps:
        # if we hit a title line
        if k: 
            # pull all paragraphs
            v = next(grps)[1]
            # skip two empty lines after title
            next(v,""), next(v,"")

            # take all lines up to next empty line/second paragraph
            print(list(takewhile(lambda x: bool(x.strip()), v)))

这会给你：

['There is a vast field of fascinating human interest, lying only just outside our doors, which as yet has been but little explored. It is the Field of Animal Intelligence.\n']
['What I am trying to do here is, find the uppercase lines, and put them all in an array. Then, using the index method, I will find the first and last paragraphs of each section by comparing the indexes of these elements of this array I created.']

每个部分的开头都有一个全大写的标题，因此一旦我们点击该标题，我们就知道有两个空行，然后第一段和模式就会重复。

要将其分解为使用循环：

from itertools import groupby  
from itertools import groupby
def parse_sec(bk):
    with open(bk) as f:
        grps = groupby(f, key=lambda x: bool(x.isupper()))
        for k, sec in grps:
            if k:
                print("First paragraph from section titled :{}".format(next(sec).rstrip()))
                v = next(grps)[1]
                next(v, ""),next(v,"")
                for line in v:
                    if not line.strip():
                        break
                    print(line)

对于您的文本：

In [11]: cat -E in.txt

THE LAY OF THE LAND$
$
$
There is a vast field of fascinating human interest, lying only just outside our doors, which as yet has been but little explored. It is the Field of Animal Intelligence.$
$
Of all the kinds of interest attaching to the study of the world's wild animals, there are none that surpass the study of their minds, their morals, and the acts that they perform as the results of their mental processes.$
$
$
WILD ANIMAL TEMPERAMENT & INDIVIDUALITY$
$
$
What I am trying to do here is, find the uppercase lines, and put them all in an array. Then, using the index method, I will find the first and last paragraphs of each section by comparing the indexes of these elements of this array I created.

美元符号是新行，输出是：

In [12]: parse_sec("in.txt")
First paragraph from section titled :THE LAY OF THE LAND
There is a vast field of fascinating human interest, lying only just outside our doors, which as yet has been but little explored. It is the Field of Animal Intelligence.

First paragraph from section titled :WILD ANIMAL TEMPERAMENT & INDIVIDUALITY
What I am trying to do here is, find the uppercase lines, and put them all in an array. Then, using the index method, I will find the first and last paragraphs of each section by comparing the indexes of these elements of this array I created.