save dictionary for later use?

[globalrev]

i extract info from one file and put it into a dictionary.
i want to save that dictionary for later use, how do i do that?
might save a list of dictionaries or a list of classobjects too if
there is any difference.

 

[jay graves]

i extract info from one file and put it into a dictionary.
i want to save that dictionary for later use, how do i do that?
might save a list of dictionaries or a list of classobjects too if
there is any difference.

use the 'pickle' module.
http://docs.python.org/lib/module-pickle.html

....
Jay Graves

 

[globalrev]

use the 'pickle' module.http://docs.python.org/lib/module-pickle.html

...
Jay Graves

pickle.dumps(mg)
pickle.load(mg)

'dict' object has no attribute 'readline'
dumps load(well i dont know but i get no complaint but running load
generates that error)

 

[jay graves]

pickle.dumps(mg)
pickle.load(mg)

'dict' object has no attribute 'readline'
dumps load(well i dont know but i get no complaint but running load
generates that error)

It's best to post a minimal set of code that exhibits your error.
You aren't saving the output of pickle.dumps and you are using
pickle.load instead of pickle.loads.

Sample loading to and from a string which you can tuck away in a file.


Sample using an open file.

....
Jay Graves

 

[Hans Nowak]

pickle.dumps(mg)
pickle.load(mg)

'dict' object has no attribute 'readline'
dumps load(well i dont know but i get no complaint but running load
generates that error)

The 'loads' and 'dumps' methods use strings:
{'this': 42, 'other': 17, 'that': 101}

If you want to store to / restore from file, use 'dump' and 'load':

# write to file 'out'...
# restore it later{'this': 42, 'other': 17, 'that': 101}

Also see http://docs.python.org/lib/pickle-example.html.

Hope this helps!

--Hans

 

[bruno.desthuilliers]

pickle.dumps(mg)
pickle.load(mg)

'dict' object has no attribute 'readline'
dumps load(well i dont know but i get no complaint but running load
generates that error)

What about *READING THAT FUCKING MANUAL* ?

http://docs.python.org/lib/node316.html
"""
dump(obj, file[, protocol])
Write a pickled representation of obj to the open file object
file. This is equivalent to Pickler(file, protocol).dump(obj).

If the protocol parameter is omitted, protocol 0 is used. If
protocol is specified as a negative value or HIGHEST_PROTOCOL, the
highest protocol version will be used.

Changed in version 2.3: Introduced the protocol parameter.

file must have a write() method that accepts a single string
argument. It can thus be a file object opened for writing, a StringIO
object, or any other custom object that meets this interface.

load(file)
Read a string from the open file object file and interpret it as a
pickle data stream, reconstructing and returning the original object
hierarchy. This is equivalent to Unpickler(file).load().

file must have two methods, a read() method that takes an integer
argument, and a readline() method that requires no arguments. Both
methods should return a string. Thus file can be a file object opened
for reading, a StringIO object, or any other custom object that meets
this interface.

This function automatically determines whether the data stream was
written in binary mode or not.
"""

Example use:

Now : it's not the first time - in a couple days - that you ask a
question that you wouldn't have asked if you had taken a couple
minutes doing the tutorial and/or reading the doc. This newsgroup is
*very* tolerant (in most other places on usenet, you would have get a
raw RTFM on the first question, and a PLONK on the second), but there
are still limits, and as far as I'm concerned you're not far from
them. So do yourself and the world a favour, read this:
http://catb.org/~esr/faqs/smart-questions.html

and then this:
http://docs.python.org/tut/tut.html

and next time someone points you to a specific module, have mercy and
*read* the doc before posting.

As far as I'm concerned, I won't anwser any of your questions unless
it's obvious that you have followed these advices (but then I'll be
happy to help if I can).

 

[castironpi]

'dict' object has no attribute 'readline'
dumps load(well i dont know but i get no complaint but running load
generates that error)

What about *READING THAT FUCKING MANUAL* ?

http://docs.python.org/lib/node316.html
"""
dump(obj, file[, protocol])
    Write a pickled representation of obj to the open file object
file. This is equivalent to Pickler(file, protocol).dump(obj).

    If the protocol parameter is omitted, protocol 0 is used. If
protocol is specified as a negative value or HIGHEST_PROTOCOL, the
highest protocol version will be used.

    Changed in version 2.3: Introduced the protocol parameter.

    file must have a write() method that accepts a single string
argument. It can thus be a file object opened for writing, a StringIO
object, or any other custom object that meets this interface.

load(file)
    Read a string from the open file object file and interpret it as a
pickle data stream, reconstructing and returning the original object
hierarchy. This is equivalent to Unpickler(file).load().

    file must have two methods, a read() method that takes an integer
argument, and a readline() method that requires no arguments. Both
methods should return a string. Thus file can be a file object opened
for reading, a StringIO object, or any other custom object that meets
this interface.

    This function automatically determines whether the data stream was
written in binary mode or not.
"""

Example use:


{'a': 1, 'b': 2}

Now : it's not the first time - in a couple days - that you ask a
question that you wouldn't have asked if you had taken a couple
minutes doing the tutorial and/or reading the doc. This newsgroup is
*very* tolerant (in most other places on usenet, you would have get a
raw RTFM on the first question, and a PLONK on the second), but there
are still limits, and as far as I'm concerned you're not far from
them. So do yourself and the world a favour, read this:http://catb.org/~esr/faqs/smart-questions.html

and then this:http://docs.python.org/tut/tut.html

and next time someone points you to a specific module, have mercy and
*read* the doc before posting.

As far as I'm concerned, I won't anwser any of your questions unless
it's obvious that you have followed these advices (but then I'll be
happy to help if I can).- Hide quoted text -

- Show quoted text -

There is 'shelve'. It's just that you have to re-update each entry
when you modify, so it's just similarity you'd be saving.

 

[castironpi]

What about *READING THAT FUCKING MANUAL* ?

http://docs.python.org/lib/node316.html
"""
dump(obj, file[, protocol])
    Write a pickled representation of obj to the open file object
file. This is equivalent to Pickler(file, protocol).dump(obj).

    If the protocol parameter is omitted, protocol 0 is used. If
protocol is specified as a negative value or HIGHEST_PROTOCOL, the
highest protocol version will be used.

    Changed in version 2.3: Introduced the protocol parameter.

    file must have a write() method that accepts a single string
argument. It can thus be a file object opened for writing, a StringIO
object, or any other custom object that meets this interface.

load(file)
    Read a string from the open file object file and interpret it as a
pickle data stream, reconstructing and returning the original object
hierarchy. This is equivalent to Unpickler(file).load().

    file must have two methods, a read() method that takes an integer
argument, and a readline() method that requires no arguments. Both
methods should return a string. Thus file can be a file object opened
for reading, a StringIO object, or any other custom object that meets
this interface.

    This function automatically determines whether the data stream was
written in binary mode or not.
"""

Example use:
{'a': 1, 'b': 2}

Now : it's not the first time - in a couple days - that you ask a
question that you wouldn't have asked if you had taken a couple
minutes doing the tutorial and/or reading the doc. This newsgroup is
*very* tolerant (in most other places on usenet, you would have get a
raw RTFM on the first question, and a PLONK on the second), but there
are still limits, and as far as I'm concerned you're not far from
them. So do yourself and the world a favour, read this:http://catb.org/~esr/faqs/smart-questions.html

and then this:http://docs.python.org/tut/tut.html

and next time someone points you to a specific module, have mercy and
*read* the doc before posting.

As far as I'm concerned, I won't anwser any of your questions unless
it's obvious that you have followed these advices (but then I'll be
happy to help if I can).- Hide quoted text -

- Show quoted text -

There is 'shelve'.  It's just that you have to re-update each entry
when you modify, so it's just similarity you'd be saving.- Hide quoted text -

- Show quoted text -

Now a shelf of filenames could be valuable.

 

[alex23]

What about *READING THAT FUCKING MANUAL* ?

I don't think he has the time.

Now : it's not the first time - in a couple days - that you ask a
question that you wouldn't have asked if you had taken a couple
minutes doing the tutorial and/or reading the doc.

It's not just here, either. He's been posting similar low-level
questions to groups on lisp, ruby, haskell, javascript, prolog, scheme
and smalltalk. Either he's crowd-sourcing his learning, needs some
serious medication for his ADD, or is just taking the piss.

Over the past couple of months, the idiots have really taken over this
group.

- alex23

 

[castironpi]

The 'loads' and 'dumps' methods use strings:

 >>> import pickle
 >>> d = {"this": 42, "that": 101, "other": 17}
 >>> s = pickle.dumps(d)
 >>> s
"(dp0\nS'this'\np1\nI42\nsS'other'\np2\nI17\nsS'that'\np3\nI101\ns."
 >>> pickle.loads(s)
{'this': 42, 'other': 17, 'that': 101}

If you want to store to / restore from file, use 'dump' and 'load':

# write to file 'out'...
 >>> f = open("out")
 >>> f = open("out", "wb")
 >>> pickle.dump(d, f)
 >>> f.close()

# restore it later
 >>> g = open("out", "rb")
 >>> e = pickle.load(g)
 >>> g.close()
 >>> e
{'this': 42, 'other': 17, 'that': 101}

Also seehttp://docs.python.org/lib/pickle-example.html.

Hope this helps!

--Hans

I want to compare that cleanliness with other languages to compare
formats.

Is pickle.load( open( 'out', 'rb' ) ) any better or worse than
pickle.load( 'out', 'rb' )?

 

[castironpi]

I want to compare that cleanliness with other languages to compare
formats.

Is pickle.load( open( 'out', 'rb' ) ) any better or worse than
pickle.load( 'out', 'rb' )?- Hide quoted text -

- Show quoted text -

This is a check-in on live-time writing. pickle.load didn't take two
parameters.