在Python中提取关键字及其间的文本

Question

首先我想说，这个地方帮了我很多，我永远也无法报答。我想感谢所有曾经帮助过我的人 :).

我正在尝试从一个特定样式的信息中分割一些文本。它的格式是这样的：

DATA|1|TEXT1|STUFF: some random text|||||
DATA|2|TEXT1|THINGS: some random text and|||||
DATA|3|TEXT1|some more random text and stuff|||||
DATA|4|TEXT1|JUNK: crazy randomness|||||
DATA|5|TEXT1|CRAP: such random stuff I cant believe how random|||||

我下面有一段代码，它将文本合并，在单词之间加上空格，并把它放到一个叫“TEXT”的字符串里，所以看起来像这样：

STUFF: some random text THINGS: some random text and some more random text and stuff JUNK: crazy randomness CRAP: such random stuff I cant believe how random

我需要它格式化成这样：

DATA|1|TEXT1|STUFF: |||||
DATA|2|TEXT1|some random text|||||
DATA|3|TEXT1|THINGS: |||||
DATA|4|TEXT1|some random text and|||||
DATA|5|TEXT1|some more random text and stuff|||||
DATA|6|TEXT1|JUNK: |||||
DATA|7|TEXT1|crazy randomness|||||
DATA|8|NEWTEXT|CRAP: |||||
DATA|9|NEWTEXT|such random stuff I cant believe how random|||||

行号很简单，我已经完成了，还有换行符。我需要的是抓取“CRAP”，并把“TEXT1”改成“NEWTEXT”。

我的代码会扫描字符串，寻找关键词，然后把它们放到自己的行上，接着在它们下面添加文本，然后再放下一个关键词，依此类推。以下是我目前的代码：

#this combines all text to one line and adds to a string
while current_segment.move_next('DATA')
    TEXT = TEXT + " " + current_segment.field(4).value

KEYWORD_LIST  = [STUFF:', THINGS:', JUNK:']
KEYWORD_LIST1 = [CRAP:']

#this splits the words up to search through
TEXT_list = TEXT.split(' ')

#this searches for the first few keywords then stops at the unwanted one
for word in TEXT_list:
    if word in KEYWORD_LIST:
        my_output = my_output + word
    elif word in KEYWORD_LIST1:
        break
    else:
        my_output = my_output + ' ' + word

#this searches for the unwanted keywords leaving the output blank until it reaches the wanted keyword
for word1 in TEXT_list:
    if word1 in KEYWORD_LIST:
        my_output1 = ''
    elif word1 in KEYWORD_LIST1:
        my_output1 = my_output1 + word1 + '\n'
    else:
        my_output1 = my_output1 + ' ' + word1

#my_output is formatted back the way I want deviding up the text into 65 or less character lines

MAX_LENGTH = 65
my_wrapped_output  = wrap(my_output,MAX_LENGTH)
my_wrapped_output1 = wrap(my_output1,MAX_LENGTH)
my_output_list     = my_wrapped_output.split('\n')
my_output_list1    = my_wrapped_output1.split('\n')

for phrase in my_output_list:
     if phrase == "":
          SetID +=1
          output = output + "DATA|" + str(SetID) + "|TEXT| |||||"
     else:
          SetID +=1
          output = output + "DATA|" + str(SetID) + "|TEXT|" + phrase + "|||||"

for phrase2 in my_output_list1:
     if phrase2 == "":
          SetID +=1
          output = output + "DATA|" + str(SetID) + "|NEWTEXT| |||||"
     else:
          SetID +=1
          output = output + "DATA|" + str(SetID) + "|NEWTEXT|" + phrase + "|||||"

#this populates the fields I need
value = output

然后我格式化“my_output”和“my_output1”，在合适的位置添加“NEWTEXT”这个词。这段代码会逐行查找关键词，然后把这个关键词和换行符放进去。一旦找到另一个“KEYWORD_LIST1”，它就会停止并丢掉剩下的文本，然后开始下一个循环。我的问题是，上面的代码给了我这个结果：

DATA|1|TEXT1|STUFF: |||||
DATA|2|TEXT1|some random text|||||
DATA|3|TEXT1|THINGS: |||||
DATA|4|TEXT1|some random text and|||||
DATA|5|TEXT1|some more random text and stuff|||||
DATA|6|TEXT1|JUNK: |||||
DATA|7|TEXT1|crazy randomness|||||
DATA|8|NEWTEXT|crazy randomness|||||
DATA|9|NEWTEXT|CRAP: |||||
DATA|10|NEWTEXT|such random stuff I cant believe how random|||||

它抓取了“KEYWORD_LIST1”之前的文本，并把它添加到NEWTEXT部分。我知道有办法从关键词和它后面的文本中创建组，但我不太清楚怎么实现。任何帮助都会非常感谢。

谢谢。

这是我为让它对我有效而做的事情：

KEYWORD_LIST  = ['STUFF:', 'THINGS:', 'JUNK:']
KEYWORD_LIST1 = ['CRAP:']

def text_to_message(text):
    result=[]
    for word in text.split():
        if word in KEYWORD_LIST or word in KEYWORD_LIST1:
            if result:
            yield ' '.join(result)
            result=[]
            yield word
        else:
            result.append(word)
    if result:
        yield ' '.join(result)

def format_messages(messages):
    title='TEXT1'
    for message in messages:
        if message in KEYWORD_LIST:
            title='TEXT1'
        elif message in KEYWORD_LIST1:
            title='NEWTEXT'
    my_wrapped_output  = wrap(message,MAX_LENGTH)
    my_output_list     = my_wrapped_output.split('\n')
    for line in my_output_list:
        if line = '':
            yield title + '|'
        else:
            yield title + '|' + line

for line in format_messages(text_to_message(TEXT)):
    if line = '':
        SetID +=1
        output = "DATA|" + str(SetID) + "|"
    else:
        SetID +=1
        output = "DATA|" + str(SetID) + "|" + line

#this is needed instead of print(line)
value = output 

Answer 1

1. 一般建议：不要像这样逐步拼接字符串：

   my_output = my_output + ' ' + word
   

   而是把 my_output 设成一个列表，把 word 加到这个列表里，最后再一次性把它们合成一个字符串：my_output = ' '.join(my_output)。（下面的 text_to_message 代码有个例子。）使用 join 方法是 构建字符串的正确方式。延迟创建字符串是有好处的，因为处理子字符串的列表比不断拆分和合并字符串要简单得多，也不用到处添加空格和换行符。

2. 学习一下 生成器。它们很容易理解，并且在处理这种文本时能给你很大帮助。

---

import textwrap

KEYWORD_LIST  = ['STUFF:', 'THINGS:', 'JUNK:']
KEYWORD_LIST1 = ['CRAP:']

def text_to_message(text):
    result=[]
    for word in text.split():
        if word in KEYWORD_LIST or word in KEYWORD_LIST1:
            if result:
                yield ' '.join(result)
                result=[]
            yield word
        else:
            result.append(word)
    if result:
        yield ' '.join(result)

def format_messages(messages):
    title='TEXT1'
    num=1
    for message in messages:
        if message in KEYWORD_LIST:
            title='TEXT1'
        elif message in KEYWORD_LIST1:
            title='NEWTEXT'
        for line in textwrap.wrap(message,width=65):
            yield 'DATA|{n}|{t}|{l}'.format(n=num,t=title,l=line)
            num+=1

TEXT='''STUFF: some random text THINGS: some random text and some more random text and stuff JUNK: crazy randomness CRAP: such random stuff I cant believe how random'''

for line in format_messages(text_to_message(TEXT)):
    print(line)