On 06/11/10 01:14, prasad rao wrote:
> Hi
>
> def cript(doc=None,data =None):
> if doc==None and data==None:doc=sys.agv1
> elif doc:
> data=open(doc,'r').read()
> data_c= binascii.hexlify(data)
> else:data_c= binascii.hexlify(data)
> if doc:
> q=tempfile.TemporaryFile()
> q.write(data_c)
> os.rename(q,doc)
> return
> return data_c
>
>
> cript(doc='./language.txt')
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> File "<stdin>", line 10, in cript
> TypeError: coercing to Unicode: need string or buffer, file found
>
> 1)Why I got the above error message with the above function?How to correct
> it?
The error message points out here:
# line 10
os.rename(q,doc)
^^^
scanning a few lines earlier, we saw:
q=tempfile.TemporaryFile()
os.rename() doesn't rename a file object; os.rename() takes two string
arguments.
> 2)Is it reasonable to have 2 if blocks in a function as above?
This is where boolean algebra can help. An elif-block will only be run
when all the if-elif blocks before it evaluates to false. IOW, your code
is equivalent to this:
if doc==None and data==None: doc=sys.agv1
if not (doc==None and data==None) and doc:
data=open(doc,'r').read()
data_c= binascii.hexlify(data)
except that "doc==None and data==None" is only evaluated once.
So, using boolean algebra (assuming a reasonable definition of == and !=):
not (doc==None and data==None) and doc
(doc!=None or data!=None) and doc
now depending on the intent of "doc" and "doc != None"; it may be
possible to simplify that to only: data != None.
Note that this is all assuming a reasonable definition of ==, !=, not,
etc and assuming no side effects and assuming that the checks are
equally lightweight.
> 3)Dose the tempfile create a fileobject on harddisk or in memory(Dose it save
> my
> file as I expect it to do)
AFAIK, tempfile creates a file in harddisk, but I've never used
tempfile, so don't quote me on that.
_______________________________________________
Tutor maillist - Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor
