Python

find string in file

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Join Date: Mar 2008

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parsifal67 parsifal67 is offline

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find string in file

Mar 14th, 2008

Hi friends !!

I'm neophite about python, my target is to create a programa that
find a specific string in text file.
How can do it?

Thanks
fel

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Join Date: Jan 2008

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ZZucker

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Re: find string in file

Mar 14th, 2008

The simplest way, but maybe not the most efficient for large files, is this:

 Help with Code Tags 
 python Syntax (Toggle Plain Text) 
# sample text for testing
# could come from a text file read like this:
"""
infile = open("my_text.txt","r")
text = infile.read()
infile.close()
"""
 
text = """\
My name is Fred Flintstone and I am a famous TV
star.  I have as much authority as the Pope, I
just don't have as many people who believe it.
"""
 
search = "Fred"
index = text.find(search)
print search, "found at index", index
 
"""
my ouput (index is zero based) -->
Fred found at index 11
"""
# sample text for testing
# could come from a text file read like this:
"""
infile = open("my_text.txt","r")
text = infile.read()
infile.close()
"""

text = """\
My name is Fred Flintstone and I am a famous TV
star.  I have as much authority as the Pope, I
just don't have as many people who believe it.
"""

search = "Fred"
index = text.find(search)
print search, "found at index", index

"""
my ouput (index is zero based) -->
Fred found at index 11
"""

Note that find() only finds the first occurrence of the search word!

Never argue with idiots, they'll just bring you down to their level and beat you with their experience.

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Join Date: Dec 2006

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woooee

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Re: find string in file

Mar 14th, 2008

FWIW this will find all occurrences of a word in a string. Also note that if you are looking for "the" it will give a hit for "then". If you only want the word, you have to search with spaces added, " the " -assuming string.lower() and that punctuation is removed

 Help with Code Tags 
 Python Syntax (Toggle Plain Text) 
found=the_string.find(word)
while found > -1:
     print word, "found at location", found
     found=the_string.find(word, found+1)
found=the_string.find(word)
while found > -1:
     print word, "found at location", found
     found=the_string.find(word, found+1)

Last edited by woooee; Mar 14th, 2008 at 7:33 pm.

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Join Date: Nov 2009

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mitsuevo

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-1

Nov 7th, 2009

I kinda have the sane problem, but i want to extract the text ocr several lines.. not just a word...
Can somone tell me how to use a RE for this?
Thanks!

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vegaseat

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Nov 7th, 2009

You should really start a new thread of your own!

The string function find() can find a subtext within a larger text, as will re.findall(). The advantage of find() is that it will give you the location in the form of an index.

Last edited by vegaseat; Nov 7th, 2009 at 12:05 pm.

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mitsuevo

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Nov 7th, 2009

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Originally Posted by vegaseat

You should really start a new thread of your own!

The string function find() can find a subtext within a larger text, as will re.findall(). The advantage of find() is that it will give you the location in the form of an index.

Thanks, but i'm a bit unsure on using the index since the length of data tends to change within the search area...

And sorry about not starting a new thread... cos in another hobby forum that i'm part of we try to post questions in a thread thats already started with a similar question so that other readers can also look back on the old answer.. i guess it depends on the forum

Thanks again guys. i'm new to DaniWeb and am loving it here! you guys are amazingly helpful!!!

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sneekula

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Nov 7th, 2009

Ah, the pros and cons on posting on an old thread.
If you are interested in a regex solution, I would start a new thread and put regex in the title.

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Join Date: Nov 2009

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mitsuevo

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Nov 7th, 2009

A friend just gave me a basic (not very professinal, but easy to move around) solution... trying that out... if it doesnt work, i sure will throw the problem at you guys again