how do you use pickle?

[John Salerno]

Here's what I have:

import pickle

data = open(r'C:\pickl e_data.txt', 'w')
image = open(r'C:\peakh ell.jpg')
pickle.Pickler( data)
data.dump(image )
data.close()
image.close()

First off, I'm not sure the second line is the way to do that. But my
main problem is I don't know how to define the steps when pickling an
object. How do you first create the object? Does it return a value? I tried:

pickler = pickle.Pickler( data)
pickle.Pickler( data)

Then I tried:

pickler.dump(im age)
data.dump(image )

Basically, I'm just confused about all the syntax involved. Which
objects do I operate on, and when? I can't find these answers in the
documentation or in the interactive help, because I don't see any examples.

Furthermore, I get this error every time:

Traceback (most recent call last):
File "C:\Documen ts and Settings\jsaler 01.TUFTS\My
Documents\Pytho n24\myscripts\c hallenges\pickl e.py", line 3, in -toplevel-
import pickle
File "C:\Documen ts and Settings\jsaler 01.TUFTS\My
Documents\Pytho n24\myscripts\c hallenges\pickl e.py", line 7, in -toplevel-
pickle.Pickler( data)
AttributeError: 'module' object has no attribute 'Pickler'

So that makes me really confused, because I must have the syntax totally
wrong if it can't even get past the initial creation of a pickler object.

[Fredrik Lundh]

Re: how do you use pickle?

John Salerno wrote:
[color=blue]
> Here's what I have:
>
> import pickle
>
> data = open(r'C:\pickl e_data.txt', 'w')
> image = open(r'C:\peakh ell.jpg')
> pickle.Pickler( data)
> data.dump(image )
> data.close()
> image.close()
>
> First off, I'm not sure the second line is the way to do that. But my
> main problem is I don't know how to define the steps when pickling an
> object. How do you first create the object? Does it return a value? I tried:
>
> pickler = pickle.Pickler( data)
> pickle.Pickler( data)
>
> Then I tried:
>
> pickler.dump(im age)
> data.dump(image )
>
> Basically, I'm just confused about all the syntax involved. Which
> objects do I operate on[/color]

any object that supports pickling.

file handles does not belong to that group (what did you expect
pickle to do with a file handle ?)

or did "object" refer to the Pickler instance? you don't really need to
bother with that; just use the dump *function* instead:

pickle.dump(obj ect, file)

but if you insist on using your own Pickler instance, you have to save
the pickler instance in a variable, and call the dump method on that in-
stance:

myfile = open(somefilena me, "wb")
mypickler = pickle.Pickler( myfile)
mypickler.dump( object)

</F>

[John Salerno]

Re: how do you use pickle?

Fredrik Lundh wrote:
[color=blue]
> file handles does not belong to that group (what did you expect
> pickle to do with a file handle ?)
>
> or did "object" refer to the Pickler instance? you don't really need to
> bother with that; just use the dump *function* instead:
>
> pickle.dump(obj ect, file)
>
> but if you insist on using your own Pickler instance, you have to save
> the pickler instance in a variable, and call the dump method on that in-
> stance:
>
> myfile = open(somefilena me, "wb")
> mypickler = pickle.Pickler( myfile)
> mypickler.dump( object)[/color]

I'm sorry, but I'm terribly confused. Nothing seems to be working for
me. I *think* what I need to pickle is an image file, but so far I think
all I'm doing is passing the file handle in as the 'object', which
probably isn't correct. How would I get the actual image object to pass
in? But I also tried pickling a string and that didn't work either.

I tried it both ways you suggest, but I can't get past the errors. I
keep getting either

AttributeError: 'module' object has no attribute 'dump' (when I use the
function)

or

AttributeError: 'module' object has no attribute 'dump' (when I create
an instance)

Is there something special I need to do to use the pickle module? My
program seems to recognize the import, but it keeps saying that nothing
is an attribute of it.

[John Salerno]

Re: how do you use pickle?

John Salerno wrote:
[color=blue]
> AttributeError: 'module' object has no attribute 'dump' (when I create
> an instance)[/color]

That should be:

AttributeError: 'module' object has no attribute 'Pickler' (when I
create an instance)

[Pythor]

Re: how do you use pickle?


John Salerno wrote:
[color=blue]
> I'm sorry, but I'm terribly confused. Nothing seems to be working for
> me. I *think* what I need to pickle is an image file,[/color]

SNIP

Hint: Read the source for that page more carefully.

[Fredrik Lundh]

Re: how do you use pickle?

John Salerno wrote:
[color=blue][color=green]
> > but if you insist on using your own Pickler instance, you have to save
> > the pickler instance in a variable, and call the dump method on that in-
> > stance:
> >
> > myfile = open(somefilena me, "wb")
> > mypickler = pickle.Pickler( myfile)
> > mypickler.dump( object)[/color]
>
> I'm sorry, but I'm terribly confused. Nothing seems to be working for
> me. I *think* what I need to pickle is an image file, but so far I think
> all I'm doing is passing the file handle in as the 'object'[/color]

define "image file". the data in the file, the file name, or some other
representation?
[color=blue]
> I tried it both ways you suggest, but I can't get past the errors. I
> keep getting either
>
> AttributeError: 'module' object has no attribute 'dump' (when I use the
> function)[/color]

did you, by any chance, name your test script "pickle.py" ?

</F>

[John Salerno]

Re: how do you use pickle?

Fredrik Lundh wrote:[color=blue]
> John Salerno wrote:
>[color=green][color=darkred]
>>> but if you insist on using your own Pickler instance, you have to save
>>> the pickler instance in a variable, and call the dump method on that in-
>>> stance:
>>>
>>> myfile = open(somefilena me, "wb")
>>> mypickler = pickle.Pickler( myfile)
>>> mypickler.dump( object)[/color]
>> I'm sorry, but I'm terribly confused. Nothing seems to be working for
>> me. I *think* what I need to pickle is an image file, but so far I think
>> all I'm doing is passing the file handle in as the 'object'[/color]
>
> define "image file". the data in the file, the file name, or some other
> representation?
>[color=green]
>> I tried it both ways you suggest, but I can't get past the errors. I
>> keep getting either
>>
>> AttributeError: 'module' object has no attribute 'dump' (when I use the
>> function)[/color]
>
> did you, by any chance, name your test script "pickle.py" ?[/color]

DOH!

[John Salerno]

Re: how do you use pickle?

Fredrik Lundh wrote:
[color=blue]
> define "image file". the data in the file, the file name, or some other
> representation?[/color]

I was being dense again. I was just opening the file, but not reading
it! After reading it, it's easy to pickle it.
[color=blue]
> did you, by any chance, name your test script "pickle.py" ?[/color]

That did the trick! Thanks!

[John Salerno]

Re: how do you use pickle?

Pythor wrote:[color=blue]
> John Salerno wrote:
>[color=green]
>> I'm sorry, but I'm terribly confused. Nothing seems to be working for
>> me. I *think* what I need to pickle is an image file,[/color]
>
> SNIP
>
> Hint: Read the source for that page more carefully.
>[/color]

Hmmm...the source doesn't say much. Is there more to do with the source
beyond using it to figure out what 'peak hell' means?

[Pythor]

Re: how do you use pickle?


John Salerno wrote:[color=blue]
> Pythor wrote:[color=green]
> > John Salerno wrote:
> >[color=darkred]
> >> I'm sorry, but I'm terribly confused. Nothing seems to be working for
> >> me. I *think* what I need to pickle is an image file,[/color]
> >
> > SNIP
> >
> > Hint: Read the source for that page more carefully.
> >[/color]
>
> Hmmm...the source doesn't say much. Is there more to do with the source
> beyond using it to figure out what 'peak hell' means?[/color]

Yes... It mentions a whole different file, which you need to use pickle
on.

[John Salerno]

Re: how do you use pickle?

Pythor wrote:[color=blue]
> John Salerno wrote:[color=green]
>> Pythor wrote:[color=darkred]
>>> John Salerno wrote:
>>>
>>>> I'm sorry, but I'm terribly confused. Nothing seems to be working for
>>>> me. I *think* what I need to pickle is an image file,
>>> SNIP
>>>
>>> Hint: Read the source for that page more carefully.
>>>[/color]
>> Hmmm...the source doesn't say much. Is there more to do with the source
>> beyond using it to figure out what 'peak hell' means?[/color]
>
> Yes... It mentions a whole different file, which you need to use pickle
> on.
>[/color]

Yikes, I even took a second look at that after you said re-read the
source and then I ignored it! Thanks!

[Pythor]

Re: how do you use pickle?


John Salerno wrote:[color=blue]
> Pythor wrote:[color=green]
> > John Salerno wrote:[color=darkred]
> >> Pythor wrote:
> >>> John Salerno wrote:
> >>>
> >>>> I'm sorry, but I'm terribly confused. Nothing seems to be working for
> >>>> me. I *think* what I need to pickle is an image file,
> >>> SNIP
> >>>
> >>> Hint: Read the source for that page more carefully.
> >>>
> >> Hmmm...the source doesn't say much. Is there more to do with the source
> >> beyond using it to figure out what 'peak hell' means?[/color]
> >
> > Yes... It mentions a whole different file, which you need to use pickle
> > on.
> >[/color]
>
> Yikes, I even took a second look at that after you said re-read the
> source and then I ignored it! Thanks![/color]

Whis is why I said carefully ;) I missed it several times myself when
I was working on the challenge.

[John Salerno]

Re: how do you use pickle?

Pythor wrote:
[color=blue]
> Whis is why I said carefully ;) I missed it several times myself when
> I was working on the challenge.[/color]

Ok, frustration has set in again. I see the file name in the source
code, but am I meant to actually access a file, or just use the name
itself? I also had to look up what 'banner' meant in Unix, which wasn't
a very fun thing to have to do for a Python puzzle.

[John Salerno]

Re: how do you use pickle?

John Salerno wrote:[color=blue]
> Pythor wrote:
>[color=green]
>> Whis is why I said carefully ;) I missed it several times myself when
>> I was working on the challenge.[/color]
>
> Ok, frustration has set in again. I see the file name in the source
> code, but am I meant to actually access a file, or just use the name
> itself? I also had to look up what 'banner' meant in Unix, which wasn't
> a very fun thing to have to do for a Python puzzle.[/color]

Ah, I should have known we weren't done with URL manipulation yet. Now I
just need to figure out what to do with this source code.

[Pythor]

Re: how do you use pickle?


John Salerno wrote:[color=blue]
> John Salerno wrote:[color=green]
> > Pythor wrote:
> >[color=darkred]
> >> Whis is why I said carefully ;) I missed it several times myself when
> >> I was working on the challenge.[/color]
> >
> > Ok, frustration has set in again. I see the file name in the source
> > code, but am I meant to actually access a file, or just use the name
> > itself? I also had to look up what 'banner' meant in Unix, which wasn't
> > a very fun thing to have to do for a Python puzzle.[/color]
>
> Ah, I should have known we weren't done with URL manipulation yet. Now I
> just need to figure out what to do with this source code.[/color]

Incidentally, there's a forum specifically for posting an receiving
hints on the challenges here:

http://www.pythonchallenge.com/forums/viewforum.php?f=1

Not that I mind helping. ;)