NameError in a Function (python 3.6)

Question

I need to define a function that opens a text file, reads it, then loads the entire file into a string. This is what I have so far:

def encrypt_file(filename):
    open_file = open(filename, 'r')
    file_content = filename.read()
    filename.close()

encrypt_file(filename)
user_input = input('enter file name: ')

This is the error I get:

encrypt_file(filename)
NameError: name 'filename' is not defined

What am I doing wrong here?

So, what _is_ `filename` in `encrypt_file(filename)`? Did you mean to pass `user_input` instead? — ForceBru, May 02 '18 at 17:47
`filename.read()` is also wrong. You'll need to do `open_file.read()` and `open_file.close()` instead. — Patrick Haugh, May 02 '18 at 17:48
What kind of function is `encrypt_file()`? it does practically nothing. — Daniele Cappuccio, May 02 '18 at 17:48

Andriy Ivaneyko · Answer 1 · 2018-05-02T17:55:45.483

0

The filename var is not defined yet, you have to swap lines a little bit:

filename = input('enter file name: ')
encrypt_file(filename)

Also some intro to How To Handle Plain Text Files in Python 3 and SO question: How do I read a text file into a string variable in Python would be useful for you.

edited May 02 '18 at 17:55

answered May 02 '18 at 17:46

Andriy Ivaneyko

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score 0 · Answer 2 · answered May 02 '18 at 17:50

Your code won't work anyway.

def encrypt_file(filename):
    open_file = open(filename, 'r')
    file_content = open_file.read()
    open_file.close()

some_filename = input('enter file name: ')
encrypt_file(some_filename)

Best Practice:

def encrypt_file(filename):
    with open(filename, 'r') as open_file:
        file_content = open_file.read()

score -1 · Answer 3 · answered May 02 '18 at 17:47

Perhaps what you want to do is:

def encrypt_file(filename):
    open_file = open(filename, 'r')
    file_content = filename.read()
    open_file.close()

filename = input('enter file name: ')
encrypt_file(filename)

Please note also the correction on the line open_file.close().

NameError in a Function (python 3.6)

3 Answers3