Python - How to check if the text is in a file txt?

Question

I have a function that checks if the text is in file.txt or not.

The function works like this: If the text is contained in the file, the file is closed. If the text is not contained in the file, it is added.

But it doesn't work.

import urllib2, re
from bs4 import BeautifulSoup as BS

def SaveToFile(fileToSave, textToSave):
    datafile = file(fileToSave)
    for line in datafile:
        if textToSave in line:
            datafile.close()
        else:
            datafile.write(textToSave + '\n')
            datafile.close()



urls = ['url1', 'url2'] # i dont want to public the links.

patGetTitle = re.compile(r'<title>(.*)</title>')

for url in urls:
    u = urllib2.urlopen(url)
    webpage = u.read()
    title = re.findall(patGetTitle, webpage) 
    SaveToFile('articles.txt', title) 
    # so here. If the title of the website is already in articles.txt 
    # the function should close the file. 
    # But if the title is not found in articles.txt the function should add it.

Hmmm.. simple. I want to check if the title (a text) is in a file (articles.txt) as title say. — WhiteWerry, Dec 21 '15 at 12:05
can you give a sample of the title and sample of the file and your output — The6thSense, Dec 21 '15 at 12:09
You question is very blunt. We don't know what you are going through. If you can't post the URL it is fine. We need to know the content of the text file and in which title it did not store the value. — The6thSense, Dec 21 '15 at 12:15
The text file is empty.. is just a txt file. When i found the title of a website (with urllib2) i want to store it in the txt file but first i need to check if the title is already in file.txt. But even if the file is empty the function didnt do anything... i dont get any error but the title is not write in the file. — WhiteWerry, Dec 21 '15 at 12:21
print title >> ['How to use urllib2 in Python'] (space) ['Reading and Writing Files in Python'] — WhiteWerry, Dec 21 '15 at 12:22

The6thSense · Accepted Answer · 2015-12-21T12:34:13.660

You can change the SaveToFile function like this

Your title is a list and not a string so you should call it like this SaveToFile('articles.txt', title[0]) to get the first element of the list

def SaveToFile(fileToSave, textToSave):
    with open(fileToSave, "r+") as datafile:
        for line in datafile:
            if textToSave in line:
                break
        else:
            datafile.write(textToSave + '\n')

Notes:

Since you very looping over an empty file the loop did not even run once.

i.e.)

for i in []:
    print i # This will print nothing since it is iterating over empty list same as yours

You have passed a list and not a string since re.findall returns a list object you have to pass the first element of the list to the function.
I have used for..else here if the loop is not terminated properly the else case will work.

i.e.)

for i in []:
    print i
else:
    print "Nooooo"

Output:

Nooooo

@WhiteWerry happy help :). But be sure you understand what I have did. — The6thSense, Dec 21 '15 at 12:36

Akshay Pratap Singh · Answer 2 · 2015-12-21T12:34:30.063

1

You should refactor your SaveToFile function to like this.

def SaveToFile(fileToSave, titleList):
    with open(fileToSave, 'a+') as f:
        data = f.read()

        for titleText in titleList:
            if titleText not in data:
                f.write(titleText + '\n')

        f.close()

This function read a content of file (if exist or created if not) and checks whether textToSave is in the file contents. If it found textToSave then, close file otherwise write content to file.

edited Dec 21 '15 at 12:34

answered Dec 21 '15 at 12:13

Akshay Pratap Singh

3,197
1
24
33

Get that error: in ' requires string as left operand, not list – WhiteWerry Dec 21 '15 at 12:18
@WhiteWerry edited my code and note, you should pass both arguments as **string**. – Akshay Pratap Singh Dec 21 '15 at 12:22
@WhiteWerry now this function supports list of titles, just use this function simply. – Akshay Pratap Singh Dec 21 '15 at 12:35
@WhiteWerry note **re.findall()** returns a __list__ , that's why **title** variable is a list of titles found in html file. – Akshay Pratap Singh Dec 21 '15 at 12:36
Thanks for the help dude :D – WhiteWerry Dec 21 '15 at 12:38

score 1 · Answer 3 · edited May 23 '17 at 12:23

Just use r+ mode like this:

def SaveToFile(fileToSave, textToSave):
    with open(fileToSave, 'r+') as datafile:
        if textToSave not in datafile.read():
            datafile.write(textToSave + '\n')

About that file mode, from this answer:

``r+''  Open for reading and writing.  The stream is positioned at the  
        beginning of the file.

And re.find_all() always return a list, so if you're trying to write a list instead of string you'll get an error.

So you could use:

def SaveToFile(fileToSave, textToSave):
    if len(textToSave) => 1:
        textToSave = textToSave[0]
    else:
        return

    with open(fileToSave, 'r+') as datafile:
        if textToSave not in datafile.read():
            datafile.write(textToSave + '\n')

Thanks for the help mate :) – WhiteWerry Dec 21 '15 at 12:38 — WhiteWerry, Dec 21 '15 at 12:38

Mike Müller · Answer 4 · 2015-12-21T12:21:13.703

0

This seems closer to your problem.

This checks if the text in the file:

def is_text_in_file(file_name, text):
    with open(file_name) as fobj:
        for line in fobj:
            if text in line:
                return True
    return False

This use the function above to check and writes the text to end of the file if it is not in file yet.

def save_to_file(file_name, text):
    if not is_text_in_file in (file_name, text):
        with open(file_name, 'a') as fobj:
            fobj.write(text + '\n')

edited Dec 21 '15 at 12:21

answered Dec 21 '15 at 12:06

Mike Müller

82,630
20
166
161

Thanks. i've tried this but i found a easy way to do it (check it in this post). – WhiteWerry Dec 21 '15 at 12:39

Python - How to check if the text is in a file txt?

4 Answers4