Pickle Stuff and Filename Recognition

**bvdet** · May 14 '07, 09:29 PM

Originally posted by Bellum

First of all, the important parts of the code...

Code:

def AddressRW(aw, ar):
    #For Reading & Writing to address file
    while aw == True:
        try:
            #(W)right
            adDict = {}
            adFile = file('address.txt', 'r')
            adDict = Dill.load(adFile)
            adFile = file('address.txt', 'w')
            newName = raw_input("Enter name of resident: ")
            if adDict.has_key(newName):
                adFile.close
                ynTest = True
                while ynTest == True:
                    overChoice = raw_input("Name already in list. Rewright? (y,n)")
                    if overChoice == 'y' or overChoice == 'Y':
                        aw = False
                        ynTest = False
                        AddressAP(True, False, False)
                    elif overChoice == 'n' or overChoice == 'N':
                        aw = False
                        ynTest = False
                    else:
                        print "...Error - Try Again..."
            else:
                adDict[newName] = raw_input('Enter Address in desired format: ')

and...

Code:

def AddressAP(edit, delete, search):
    #For searching, editing, and deleting address names
    while edit == True:
        try:
            adDict = {}
            adFile = file('address.txt', 'r')
            adDict = Dill.load(adFile)
            adFile = file('address.txt', 'w')
            dictSearch = raw_input("Whose address do you want to edit? ")
            if adDict.has_key(dictSearch):
                adDict[dictSearch] = raw_input("What is the new address? ")
                Dill.dump(adDict, adFile)
                adFile.close
                edit = False
            else:
                print "Name not on file."
                edit = False
        except EOFError:
            print "No addresses on file..."
            edit = False

When you run the code and run into a name that's already on file, you get the option to go onto the edit section of the code. When you do this, though, the program always gets the EOFError. I'm guessing the data in the file is deleted (or moved directly to? excuse my ignorance) when it's moved into memory. It's not put back until you leave both functions. I'm not sure how to get around this.

The other problem is that on my school computer, it doesn't recognize 'address.txt' as being there. I keep getting this message:

Code:

Traceback (most recent call last):
  File "C:\Python24\Lib\site-packages\pythonwin\pywin\framework\scriptutils.py", line 310, in RunScript
    exec codeObject in __main__.__dict__
  File "C:\Documents and Settings\student4\Desktop\Python Programs\Addressbook\addressbook.py.py", line 140, in ?
    AddressRW(False, True)
  File "C:\Documents and Settings\student4\Desktop\Python Programs\Addressbook\addressbook.py.py", line 53, in AddressRW
    adFile = file('address.txt', 'r')
IOError: [Errno 2] No such file or directory: 'address.txt'

But I think this probably has something to do with the way the cmd prompt is setup...

I noticed a few things. Each 'try' must have an 'except' or a 'finally'. You should not use 'try...except' statements until your code is debugged. Some errors can be obfuscated. I assume 'Dill' was defined with 'from pickle import Unpickler as Dill'? This clouds the intent of your code when you ask for help. A pickle file is loaded like this:

Code:

pickle.Unpickler(open(file_name)).load()

Close a file like this:

Code:

f=open(file_name, 'w')
...do stuff...
f.close()

Notice the '()'. If an error occurs when the file is opened, it may never be written and you will end up with an empty file.

Code:

f = open(file_name, 'w')
# dumps one object
pickle.Pickler(f).dump(object)
f.close()
# loads one object
pickle.Unpickler(open(file_name)).load()

**Bellum** · May 15 '07, 03:03 PM

Oh, I'm sorry. I'd completely forgotten the Dill thing. It's

import cPickle as Dill

Don't quite understand why I would only import Unpickler as I'm also dumping stuff..?

But yeah, I see what you’re saying. I can't believe I forgot to put the () after .close, and I didn't use Unpickler at all.

Anyway, thanks for the help, I'll probably re-write a bit of it tonight and see how it works.

**Bellum** · May 16 '07, 03:35 PM

Hmm...

pickle.Pickler( adFile).dump(ad Dict)

returns a value error. I'm still playing around with it. Didn't have much time to look at everything last night.

About the IOError, I'm thinking it has something to do with the security settings on this computer. Perhaps student users don't have permission to write the right thing, I don't know. Would anyone know what security settings might effect Pythons ability to write to files?

Pickle Stuff and Filename Recognition

Pickle Stuff and Filename Recognition

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