CSV error opening file - csv

Question

I am getting an error opening a file that I can't resolve. I am able to open
this exact file with no issues using another small program I wrote.
First Program (doesn't work):
import csv
passwd = "f:\mark\python\etc_password.txt"
output = "f:\mark\python\output.txt"
with open(passwd, 'r') as passwd1, open(output, 'w') as output1:
ro = csv.reader(passwd1, delimiter=':')
wo = csv.writer(output1, delimiter='\t')
for record in ro:
# if not record[0].startswith('#'):
if len(record) > 1:
wo.writerow((record[0], record[2]))
Error:
Traceback (most recent call last):
File "C:/Users/Mark/PycharmProjects/main/main.py", line 11, in <module>
for record in ro:
ValueError: I/O operation on closed file.
Second Program (works):
etcfile = "f:\mark\python\etc_password.txt"
users = {}
with open(etcfile, "r") as datafile:
for line in datafile:
if not line.startswith("#"):
info = line.split(':')
users[info[0]] = info[2]
for username in sorted(users):
print("{}:{}".format(username, users[username]))
The first program has the issue that I can't figure out. The second program works just fine opening the same file.

Answer 1

The error ValueError: I/O operation on closed file. is telling you
you cannot read from a closed file. If you look at the indentation of your
first program, you are opening a csv reader to a file which is then closed
at the end of the with block. A simpler example of this behavior would be
In [1]: import csv
In [2]: file = open('test.csv')
In [3]: ro = csv.reader(file)
In [4]: file.close()
In [5]: for record in ro:
...: print(record)
...:
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-5-1f7adaf76d31> in <module>()
----> 1 for record in ro:
2 print(record)
3
ValueError: I/O operation on closed file.