为什么会出现I/O错误？

Question

这是我代码的一部分，我试着运行它并在第12行收到这个错误此处：ValueError：对关闭的文件执行I/O操作。但我确信文件“currentRecords”是打开的。怎么了？你知道吗

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

您似乎想写出用破折号分隔的字段值。我们来看看正确的方法。你知道吗

您需要的代码是：

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

这会将每个字段转换为一个字符串（如果它还不是一个），并用破折号连接字符串，然后在行尾之间插入破折号。你知道吗

Answer 2

Jambofun解释了原因。下面是一个更有效的方法：

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))

注意最后一行，我不确定你在做你想做的事。你现在正在积累所有的记录。你知道吗