Re: Best way to pickle functions
As in Python everythong is an object you could use __name__. import cPickle def def1(): ...pass def def2(): ...pass def1.__name__ def1 def2.__name__ def2 in this case you can combine __name__ to get the object name and then combine it with eval to pickle. pickleString = stored = cPickle.dumps( + def1.__name__ + ) eval(pickleString) restored = cPickle.loads(stored) in this way you deal with dynamic strings and you can pickle anything -- http://mail.python.org/mailman/listinfo/python-list
Best way to pickle functions
I have a number of functions that I need to pickle without necessarily knowing their names in advance. My first thought was to put all the functions in a class, then pickle the class, but it doesn't really work like I expected it to. import cPickle class PickleClass: def Awesome(self): pass stored = cPickle.dumps(PickleClass) del PickleClass restored = cPickle.loads(stored) Results: Traceback (most recent call last): File pickletest.py, line 7, in module restored = cPickle.loads(stored) AttributeError: 'module' object has no attribute 'PickleClass' So, the class itself isn't being pickled, just an instance of it. This being the case, what's the best way to store these functions? Maybe dump the class to a string and pull them back with an exec statement when I need them? -- http://mail.python.org/mailman/listinfo/python-list
Re: Best way to pickle functions
On Apr 3, 11:04 am, Aaron Scott aaron.hildebra...@gmail.com wrote: I have a number of functions that I need to pickle without necessarily knowing their names in advance. My first thought was to put all the functions in a class, then pickle the class, but it doesn't really work like I expected it to. import cPickle class PickleClass: def Awesome(self): pass stored = cPickle.dumps(PickleClass) snip So, the class itself isn't being pickled, just an instance of it. This being the case, what's the best way to store these functions? Maybe dump the class to a string and pull them back with an exec statement when I need them? All pickling a class does is pickle its module and name. You can't pickle functions in principle because byte-code is sensitive and volatile, and is least likely to run consistently later on. 'pickle' is not just for serialization, it's for persistence. Pickling the source code is much sturdier. It's very unlikely that the same code runs differently in different interpreters. It's much more likely that the same code runs the same, or not at all. It's better yet to just get the source from the original place every time: instead, pickle a file name and open the file. -- http://mail.python.org/mailman/listinfo/python-list
Re: Best way to pickle functions
Pickling the source code is much sturdier. It's very unlikely that
the same code runs differently in different interpreters. It's much
more likely that the same code runs the same, or not at all.
Okay, I've run into another problem. I've saved the code to a string,
so I can call it up when I need it. I want to keep these functions all
together, though, so I'm pushing them into a dictionary when I execute
it. It seems like when I put it in a dictionary, though, it messes up
the scope of the functions contained within. For example:
import cPickle
def Main():
holder = {}
functiontest = def PickleTest():\n\tprint cPickle
exec functiontest in holder
print holder[PickleTest]()
Main()
... produces:
Traceback (most recent call last):
File pickletest.py, line 11, in module
Main()
File pickletest.py, line 9, in Main
print holder[PickleTest]()
File string, line 2, in PickleTest
NameError: global name 'cPickle' is not defined
Is there any way to do this so that the functions have access to the
higher scope?
Thanks.
--
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Re: Best way to pickle functions
Never mind. Solved the problem by putting the functions in a class and dumping that into a string. Then, when I need it, I executed the string to get myself the class, then created an instance of that class which gave me access to those functions along with the correct scope. Probably not the smartest solution, but it works for now. -- http://mail.python.org/mailman/listinfo/python-list
Re: Re: Best way to pickle functions
Aaron Scott wrote: Pickling the source code is much sturdier. It's very unlikely that the same code runs differently in different interpreters. It's much more likely that the same code runs the same, or not at all. Okay, I've run into another problem. I've saved the code to a string, so I can call it up when I need it. I want to keep these functions all together, though, so I'm pushing them into a dictionary when I execute it. It seems like when I put it in a dictionary, though, it messes up the scope of the functions contained within. For example: import cPickle def Main(): holder =} functiontest =def PickleTest():\n\tprint cPickle exec functiontest in holder print holder[PickleTest]() Main() ... produces: Traceback (most recent call last): File pickletest.py, line 11, in module Main() File pickletest.py, line 9, in Main print holder[PickleTest]() File string, line 2, in PickleTest NameError: global name 'cPickle' is not defined Is there any way to do this so that the functions have access to the higher scope? Thanks. Why not use import ? Simply recreate the source file, if necessary, and import it again. If you must import without it being in a clear text file, check out the deprecated imputil module, standard in 2.x, but removed in Python 3.0. And if you find some way to get __import__ or one of its relatives to work from a stream instead of a file, please let us know. -- http://mail.python.org/mailman/listinfo/python-list
Re: Best way to pickle functions
Why not use import ? Simply recreate the source file, if necessary, and import it again. Ah, you'd think it would be that easy :P The problem with just importing a module is that the module is then cached in memory. Multiple copies of the program are running on a server, and each of them have something akin to a randomfunctions module. When the first program is accessed, it loads randomfunctions. When the second program is accessed, it uses the randomfunctions module already in memory, even though it doesn't contain the right functions. So, I have to pull in these functions dynamically. -- http://mail.python.org/mailman/listinfo/python-list
Re: Best way to pickle functions
On Apr 3, 3:48 pm, Aaron Scott aaron.hildebra...@gmail.com wrote: Why not use import ? Simply recreate the source file, if necessary, and import it again. Ah, you'd think it would be that easy :P The problem with just importing a module is that the module is then cached in memory. Multiple copies of the program are running on a server, and each of them have something akin to a randomfunctions module. When the first program is accessed, it loads randomfunctions. When the second program is accessed, it uses the randomfunctions module already in memory, even though it doesn't contain the right functions. So, I have to pull in these functions dynamically. Here I found this cookie you can have it. /cookie imp.load_source(name, pathname[, file]) Load and initialize a module implemented as a Python source file and return its module object. If the module was already initialized, it will be initialized again. 'again' was actually in italics in the docs. /much rejoicing I presume you're aware of eval and exec. -- http://mail.python.org/mailman/listinfo/python-list
