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if __name__ == '__main__':
    filename = open('sevi.txt', 'wb')
    content = filename.write("Cats are smarter than dogs")
    for line in content.read(): 
        match = re.findall('[A-Z]+', line)
        print match
    filename.close()

I am new to python. I am just opening a file and writing some text into it. Later reading the content find all the characters in it by using regular expression. but I am getting the error as 'NoneType' object has no attribute 'read'. if I use readlines also, I am getting the error.

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  • TIP: try printing content and see Commented Feb 17, 2016 at 12:59
  • 3
    filename.write() returns None in Python 2. Did you mean to use filename.read() instead? You'll need to open the file in w+ mode to be able to do that though. Commented Feb 17, 2016 at 13:00
  • i am getting the error as None Traceback (most recent call last): File ".\mud.txt", line 12, in <module> for line in content.read(): AttributeError: 'NoneType' object has no attribute 'read' Commented Feb 17, 2016 at 13:01
  • 1
    FWIW, the open function takes a file name string and returns a file object, so calling that file object filename is somewhat confusing. Commented Feb 17, 2016 at 13:10

3 Answers 3

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6

The file.write() method returns None in Python 2 (in Python 3 it returns the number of bytes written, for a binary file).

If you want to both write and read with the same file you'll need to open that file in w+ mode, and seek back to put the file position back to the start:

with open('sevi.txt', 'w+b') as fileobj:
    fileobj.write("Cats are smarter than dogs")
    fileobj.seek(0)  # move back to the start
    for line in fileobj: 
        match = re.findall('[A-Z]+', line)
        print match

Note that looping over the file object can be done directly, producing individual lines.

I made two other changes: I renamed your variable to fileobj; you have a file object, not just the name of the file here. And I used the file object as a context manager, so that it is closed automatically even if any errors occur in the block.

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5 Comments

but it is printing as : ['Z', 'Z', 'Z', 'Z', 'Z'] ['Z'] ['X', 'P', 'R', 'C', 'R', 'R', 'R', 'R', 'R', 'C'] ['B', 'E', 'BCDEFGHIH', 'NOPQRSTUK', 'Z', 'N', 'Q', 'T', 'W', 'Z', 'R', 'R', 'R', 'R', 'R', 'R'] ['I'] ['V', 'E', 'R', 'R', 'R', 'R', 'C', 'P', 'Y', 'S', 'C']
@sam: Yes, isn't that what you expected? You didn't tell us anything about what you were trying to do.
@sam: your find_all() call finds all groups of uppercase letters and returns a list of them. So if your text includes only individual Z initials, that's what you get returned.
if i want to search for specifi word in my .txt (example - smarter). then what should i do ? . If i want to find only letters within my .txt.
@sam: that's an entirely new problem, separate from your question, and too broad to answer in comments.
0

filename.write("Cats are smarter than dogs") is the function that returns None type like every function in Python if it's not specified otherwise with a return statement. So the value of the variable content is None and You are trying to read from that. Try filename.read() instead.

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import re 

ofile = open('sevi.txt', 'r+')

ofile.write("Cats are smarter than dogs")

ofile.seek(0)

data = ofile.read()

upper = re.findall(r'[A-Z]', data)

print upper

lower = re.findall(r'[a-z]', data)

print lower

ofile.close()
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