从python中的文本文件中提取重复模式

Question

I am looking to extract all the text between a repeating pattern in a text file. My text file XYZ.txt looks something like this:

Start

This is a great day

End

Start
This is another great day

End

Start
This is 3rd great day
End

I am looking extract the all the text between every start and End, my output should be like:

This is a great day
This is another great day
This is 3rd great day

and I am looking to save all the outputs as separate HTML file. The code that I am using is as follows:

import re
with open('XYZ.txt') as myfile:
    content = myfile.read()

text = re.search(r'Start\n.*?End', content, re.DOTALL).group()

print(text)

But code above only prints the first line. Not sure how I can print all the values between the pattern and save them as seperate html files. I would really appreciate any directions.

Thank You

Answer 1

You need to use re.findall to find all occurrences of regex.

>>> lines
'Start\n\nThis is a great day\n\nEnd\n\nStart\nThis is another great day\n\nEnd\n\nStart\nThis is 3rd great day\nEnd\n'
>>>
>>> re.findall('This is.*day', lines)
['This is a great day', 'This is another great day', 'This is 3rd great day']

Answer 2

You could use string mutation and generators instead of re.

def format_file(file, start, end):
    f = open(file, 'r').read()
    return tuple(x for x in ''.join(f.split(start)).replace('\n', '').split(end) if x != '')

print format_file('XYZ', 'Start', 'End')

Or pure generator

def format_file(file, start, end):
    f = open(file, 'r').readlines()
    return tuple(x.rstrip() for x in f if x != '\n' and not x.startswith(start) and not x.startswith(end))
print format_file('XYZ', 'Start', 'End')

Answer 3

I would use the readlines() function and do something like this:

with open('jokes.txt') as myfile:
    for line in myfile.readlines():
        if line.strip() != 'Start' and line.strip() != 'End' and line.strip():
            print line[:-1]

This will give output:

This is a great day
This is another great day
This is 3rd great day

And furthermore will generalize to any type of string between 'Start' and 'End'

Answer 4

If your text file looks like in your post, then you may not need regex , you can use list comprehension .

You can just store all the lines you want to extract in a list.

lst = []
with open('XYZ.txt', 'r') as myfile:
    for line in myfile:
        line = line.strip()
        lst.append(line)
lst2 = [i for i in lst if i != 'Start' and i != 'End' ]        
print lst2 

The output:

['This is a great day', 'This is another great day', 'This is 3rd great day']