Extract text

[rektcol]

Hello everyone,
I hope it will be comprehensible.

I have to extract text from file in repository. These files are like :

"
titi
titi
titi
yes
ok
ok
ok
no
totot
tototo
tot
"

How can i extract text behind yes and no ? I would like to have all these 'ok' ?

My output should be :

yes
ok
ok
ok
no

i'm able to read these file with os but i dont know how to extract correctly...

thanks for help !

[DeaD_EyE]

Example with a generator:

1. assign False to start_found
   
2. iterate line by line, which should be word for word
   
3. if start was found, change start_found to True
   
4. yield element if start_found is True
   
5. return from generator, if end is the element. This will also leave the for-loop
   
6. optional Exceptions:
   • if the for-loop was finished, but start_found is still False, then start-word was not found
     
   • if the for-loop was finished and start_found is True, then the end-word was not found
     

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word_start = "yes" word_end = "no"   words = """yes ok ok ok no""".splitlines()   def split(sequence, start, end):     start_found = False       for element in sequence:         if element == word_start and not start_found:             start_found = True         elif element == word_end and start_found:             return             # close generator         elif start_found:             yield element       # this point is reached, if the start or end was not found     if start_found:         # seen start, but no end         raise ValueError(f"'{end}' was not the last element in sequence")     else:         # seen no start in the whole sequence         raise ValueError(f"The start_word '{start}' was not found in sequence")   oks = list(split(words, word_start, word_end)) print(oks)

Here the Version, which includes start-word and stop-word.
It has no big difference compared to the previous generator-function.

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word_start = "yes" word_end = "no"   words = """yes ok ok ok no""".splitlines()   def split(sequence, start, end):     start_found = False       for element in sequence:         if element == word_start and not start_found:             start_found = True             yield element         elif element == word_end and start_found:             yield element # yield the word_end             return             # close generator         elif start_found:             yield element       # this point is reached, if the start or end was not found     if start_found:         # seen start, but no end         raise ValueError(f"'{end}' was not the last element in sequence")     else:         # seen no start in the whole sequence         raise ValueError(f"The start_word '{start}' was not found in sequence")   oks = list(split(words, word_start, word_end)) print(oks)

[Gribouillis]

You could use module itertools

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import io import itertools as itt   file = io.StringIO("""\ titi titi titi yes ok ok ok no totot tototo tot """)   def takeuntil(pred, seq):     for elem in seq:         yield elem         if pred(elem):             return   seq = itt.dropwhile((lambda line: line != 'yes\n'), file) seq = takeuntil((lambda line: line == 'no\n'), seq)   print(''.join(seq), end='')

Output:
yes
ok
ok
ok
no

[ibreeden]

Also have a look at this thread: Extract a string between 2 words from a text file.

[Gribouillis]

An even more functional version

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from functools import partial import io from itertools import dropwhile import operator import sys   def equal(x):     return partial(operator.eq, x)   def not_equal(x):     return partial(operator.ne, x)   def takeuntil(pred, seq):     for elem in seq:         yield elem         if pred(elem):             return   file = io.StringIO("""\ titi titi titi yes ok ok ok no totot tototo tot """)   seq = takeuntil(equal('no\n'), dropwhile(not_equal('yes\n'), file))   sys.stdout.writelines(seq)

Output:
yes
ok
ok
ok
no

[rektcol]

First, i learned many tricks and then i just debug myself !
Thanks a lot guys, these solutions are working well.

Imagine now if my input contains a number. for each file, the number is different.
for exemple the first file is :
"""
titi
12 yes
ok
no
eee
"""

and the other file could be like :

"""
titi
14 yes
ok
no
eee
"""

How can i specify that these number are changing. I mean, python is searching the exact file. Is it possible to indicate that some string could be not the same ?

[Gribouillis]

For varying text, you can use regular expressions

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import re   lines = dropwhile(re.compile(r'(?!^\d+\s+yes\s*$)').match, file) lines = takeuntil(equal('no\n'), lines) sys.stdout.writelines(lines)

Output:
12 yes
ok
ok
ok
no