python - An integer is required? open()

45
votes

I have a very simple python script that should scan a text file, which contains lines formatted as id='value' and put them into a dict. the python module is called chval.py and the input file is in.txt. here's the code:

import os,sys
from os import *
from sys import *

vals = {}

f = open(sys.argv[1], 'r')

for line in val_f:
    t = line.split('=')
    t[1].strip('\'')
    vals.append(t[0], t[1])

print vals

f.close()

when i try to run it i get:

Traceback (most recent call last):
File "chval.py", line 9, in ? f = open(sys.argv[1], 'r') TypeError: an integer is required

I'm using python 2.4... because i've been challenged to not use anything newer, is there something about open() that I don't know about? Why does it want an integer?

anything after that line is untested. in short: why is it giving me the error and how do i fix it?

5
pythonfile-iointegerargv
Your script has a bug in it. vals is a dictionary, which does not have an append method. You want to just assign with vals[t[0]]=t[1] - Christopher
also, it's supposed to be "for line in f:" as opposed to val_f - Sev
yeah sev, i had gone through and changed my variable halfway through... thanks for pointing that out. - Victor
so i had added another issue to my problem where i was getting a "file not found error" the machine i'm on at work is set to hide extensions so the file was called in.txt.txt instead of just in.txt - Victor
yeah my comment was unclear, i was originally getting an error that the file in.txt was did not exist, but in my mind "that's impossible!" so i started throwing things into my code. one of which was "from os import *" that brought up a different error and i assumed i had fixed one problem to find another. after this question was answered my code reverted back to the original error. So I edited my question to address the issue, upon finding that my machine was not showing extensions and that in.txt indeed did not exist i re-edited my question and left my previous comment in case it was read. - Victor

5 Answers

77
votes

Because you did from os import *, you are (accidenally) using os.open, which indeed requires an integer flag instead of a textual "r" or "w". Take out that line and you'll get past that error.

13
votes

Don't do import * from wherever without a good reason (and there aren't many).

Your code is picking up the os.open() function instead of the built-in open() function. If you really want to use os.open(), do import os then call os.open(....). Whichever open you want to call, read the documentation about what arguments it requires.

12
votes

Also of note is that starting with Python 2.6 the built-in function open() is now an alias for the io.open() function. It was even considered removing the built-in open() in Python 3 and requiring the usage of io.open, in order to avoid accidental namespace collisions resulting from things such as "from blah import *". In Python 2.6+ you can write (and can also consider this style to be good practice):

import io
filehandle = io.open(sys.argv[1], 'r')
5
votes

Providing these parameters resolved my issue:

with open('tomorrow.txt', mode='w', encoding='UTF-8', errors='strict', buffering=1) as file:
    file.write(result)
0
votes

From http://www.tutorialspoint.com/python/os_open.htm you could also keep your import and use

file = os.open( "foo.txt", mode )

and the mode could be :

os.O_RDONLY: open for reading only
os.O_WRONLY: open for writing only
os.O_RDWR : open for reading and writing
os.O_NONBLOCK: do not block on open
os.O_APPEND: append on each write
os.O_CREAT: create file if it does not exist
os.O_TRUNC: truncate size to 0
os.O_EXCL: error if create and file exists
os.O_SHLOCK: atomically obtain a shared lock
os.O_EXLOCK: atomically obtain an exclusive lock
os.O_DIRECT: eliminate or reduce cache effects
os.O_FSYNC : synchronous writes
os.O_NOFOLLOW: do not follow symlinks