Is it possible to use csv.writer to write data to a variable rather than a file?
I was hoping I could do something like this:
data = ''
csv.writer(data)
# ...... (I have removed the csv processing code for brevity)
message = EmailMessage('Invoice for 2012', 'h', 'noreply@test.co.uk', ['test@test.co.uk'])
message.attach('invoice.csv', data, 'text/csv')
message.send()
When I execute the code I get the following error:
argument 1 must have a "write" method
The csv.writer
class needs a file-like object, something with a .write()
method. A StringIO
class would be best here:
from cStringIO import StringIO
data = StringIO()
csv.writer(data)
# write your stuff
message = EmailMessage('Invoice for 2012', 'h', 'noreply@test.co.uk', ['test@test.co.uk'])
message.attach('invoice.csv', data.getvalue(), 'text/csv')
message.send()
I used the C-variant of the StringIO
module there; the advantage is speed, the disadvantage that you can use each instance only as a writable or a readable file. Since all you do is write to it before retrieving the written data, that's just fine.
You can always use StringIO
whenever you need a file-like object (with a write
method) and do not want to create an actual file in the filesystem.
An advantage of this memory-file approach is that I/O is much faster than with a real storage backend. If you want to be even faster, you can use cStringIO
. Note that cStringIO
is not always available, so you could do something like
try:
import cStringIO as StringIO
except ImportError:
import StringIO
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