ValueError : I/O operation on closed file

Question

import csv    

with open('v.csv', 'w') as csvfile:
    cwriter = csv.writer(csvfile, delimiter=' ', quotechar='|', quoting=csv.QUOTE_MINIMAL)

for w, c in p.items():
    cwriter.writerow(w + c)

Here, p is a dictionary, w and c both are strings.

When I try to write to the file it reports the error:

ValueError: I/O operation on closed file.

Asked By: GobSmack

||

Source

Answer 1

Indent correctly; your for statement should be inside the with block:

import csv    

with open('v.csv', 'w') as csvfile:
    cwriter = csv.writer(csvfile, delimiter=' ', quotechar='|', quoting=csv.QUOTE_MINIMAL)

    for w, c in p.items():
        cwriter.writerow(w + c)

Outside the with block, the file is closed.

>>> with open('/tmp/1', 'w') as f:
...     print(f.closed)
... 
False
>>> print(f.closed)
True

Answered By: falsetru

Answer 2

Same error can raise by mixing: tabs + spaces.

with open('/foo', 'w') as f:
 (spaces OR  tab) print f       <-- success
 (spaces AND tab) print f       <-- fail

Answered By: Slake

Answer 3

I was getting this exception when debugging in PyCharm, given that no breakpoint was being hit. To prevent it, I added a breakpoint just after the with block, and then it stopped happening.

Answered By: Asclepius

Answer 4

file = open("filename.txt", newline='')
for row in self.data:
    print(row)

Save data to a variable(file), so you need a with.

Answered By: Yi Rong Wu

Answer 5

I had this problem when I was using an undefined variable inside the with open(...) as f:.
I removed (or I defined outside) the undefined variable and the problem disappeared.

Answered By: Luca Urbinati

Answer 6

Another possible cause is the case when, after a round of copypasta, you end up reading two files and assign the same name to the two file handles, like the below. Note the nested with open statement.

with open(file1, "a+") as f:
    # something...
    with open(file2, "a+", f):
        # now file2's handle is called f!

    # attempting to write to file1
    f.write("blah") # error!!

The fix would then be to assign different variable names to the two file handles, e.g. f1 and f2 instead of both f.

Answered By: Anis R.

Answer 7

I also have the same problem.
Here is my previous code

csvUsers = open('/content/gdrive/MyDrive/Ada/Users.csv', 'a', newline='', encoding='utf8')
usersWriter = csv.writer(csvUsers)
for t in users:
    NodeWriter=.writerow(users)
csvUsers.close()

Apparently, I shoud write the usersWriter instead of NodeWriter.

NodeWriter=.writerow(users)
usersWriter=.writerow(users)

Below is my current code and it is working

csvUsers = open('/content/gdrive/MyDrive/Ada/Users.csv', 'a', newline='', encoding='utf8')
usersWriter = csv.writer(csvUsers)
for t in users:
    usersWriter=.writerow(users)
csvUsers.close()

Answered By: May

ValueError : I/O operation on closed file

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