CSV错误打开文件
问题描述:
我收到一个错误,打开一个我无法解析的文件。我能够使用我编写的另一个小程序打开 这个确切的文件,没有任何问题。CSV错误打开文件
的第一个程序(不起作用):
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]))
错误:
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.
第二个程序(工作):
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]))
第一个程序存在我无法弄清楚的问题。第二个程序可以很好地打开同一个文件。
答
错误ValueError: I/O operation on closed file.
告诉你 你无法从封闭文件中读取。如果您查看 第一个程序的缩进,您将打开一个csv阅读器,然后在with块的末尾关闭 。这种行为的一个更简单的例子是
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.