Why do I get an I/O Error?

Question

This is part of my code, I try running it and receive this error on line 12 here:ValueError: I/O operation on closed file. But I am sure that the file, 'currentRecords' is open. What is wrong?

c.execute("SELECT * FROM Student, Behaviour")
data = c.fetchall()
currentRecords = open('Current Records - Unsorted', 'w')
l = []
for i in data: #for individual records in the whole database do:
    record = str(i)
    record = record.replace("u'","")
    record = record.replace("'", "")
    record = record.replace("(","") 
    record = record.replace(")", "")
    record = record.replace(","," -")
    currentRecords.write(record+"\r\n")
    currentRecords.write('----------------------------------'+"\r\n")
    currentRecords.close()
    y = open('Current Records - Unsorted','r')
    z = y.read() #opening the file containing the unsorted, formatted records to read
    l.append(z)
    y.close() #z is an array that holds all the records (each record has its own index within l)

Answer 1

Jambofun has explained why. Here is a more efficient way of doing it:

c.execute("SELECT * FROM Student, Behaviour")
data = c.fetchall()
currentRecords = open('Current Records - Unsorted', 'w')
dashes = '----------------------------------'
l = []
for i in data: #for individual records in the whole database do:
    record = str(i)
    record = record.replace("u'","")
    record = record.replace("'", "")
    record = record.replace("(","") 
    record = record.replace(")", "")
    record = record.replace(","," -")
    record = "\r\n".join((record, dashes)) + "\r\n"
    currentRecords.write(record)

    l.append(''.join(l))

Note the last line, I am not sure you are doing what you want to do. You are accumulating all the records to the moment.

Answer 2

You appear to want to write out the field values separated by dashes. Let's take a look at the right way to do that.

The code you need is:

record = "\r\n{}\r\n".format("-".join(str(f) for f in row))

This converts each field to a string (if it isn't already one) and joins up the strings with dashes then inserts that between the line endings.