[Tutor] How does Shelve work?

Fri, 6 Sep 2002 19:41:29 -0700

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> Ibraheem Umaru-Mohammed <umarumohammed@btinternet.com> S A <buc40@bemail.org>Cc: tutor@python.org
> Re: [Tutor] How does Shelve work?Date: Fri, 6 Sep 2002 12:18:06 +0100
>
>Does the following help at all?
>
>,---- [ shelve module example - foo.py ]
>| #!/usr/bin/env python
>| import shelve
>|
>| handle = shelve.open("mydb")
>| # save objects
>| handle[1]="one"
>| handle[2]="two"
>| handle[3]="three"
>| handle[4]="four"
>| handle[5]="five"
>|
>| # retrieve objects
>| print "Stored the following to database: "
>| for item in handle.keys():
>|   print item, "=>", handle[item]
>| handle.close()
>`----
>
>You may also want to look at the following, although it wasn't all that 
helpful:
>
>,---- [ shelve module URL ]
>| http://www.python.org/doc/current/lib/module-shelve.html
>`----

Yes. That is a foot in the right direction. However:
handle[1]="one"

needs to be changed to:
handle['1']= "one"

Otherwise I get the following error:
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/sw/lib/python2.1/shelve.py", line 77, in __setitem__
    self.dict[key] = f.getvalue()
TypeError: gdbm mappings have string indices only

I gather from the error that the key must be a string item.

I wish there was better info on the shelve module. It looks to be very useful 
for small flat db files. Unfortunately, I had already tried the link you 
suggested, and you are correct, it was not very informative. But with your help, 
I was able to figure out how to work this module. Thank you very much.

Does anyone else on the list have anything to add to this discussion?

Thanks.
SA

"I can do everything on my Mac that I used to do on my PC, plus alot more ..."

-Me

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> Ibraheem Umaru-Mohammed <umarumohammed@btinternet.com> S A <buc40@bemail.org>Cc: tutor@python.org
> Re: [Tutor] How does Shelve work?Date: Fri, 6 Sep 2002 12:18:06 +0100
>
>Does the following help at all?
>
>,---- [ shelve module example - foo.py ]
>| #!/usr/bin/env python
>| import shelve
>|
>| handle = shelve.open("mydb")
>| # save objects
>| handle[1]="one"
>| handle[2]="two"
>| handle[3]="three"
>| handle[4]="four"
>| handle[5]="five"
>|
>| # retrieve objects
>| print "Stored the following to database: "
>| for item in handle.keys():
>|   print item, "=>", handle[item]
>| handle.close()
>`----
>
>You may also want to look at the following, although it wasn't all that 
helpful:
>
>,---- [ shelve module URL ]
>| http://www.python.org/doc/current/lib/module-shelve.html
>`----

Yes. That is a foot in the right direction. However:
handle[1]="one"

needs to be changed to:
handle['1']= "one"

Otherwise I get the following error:
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/sw/lib/python2.1/shelve.py", line 77, in __setitem__
    self.dict[key] = f.getvalue()
TypeError: gdbm mappings have string indices only

I gather from the error that the key must be a string item.

I wish there was better info on the shelve module. It looks to be very useful 
for small flat db files. Unfortunately, I had already tried the link you 
suggested, and you are correct, it was not very informative. But with your help, 
I was able to figure out how to work this module. Thank you very much.

Does anyone else on the list have anything to add to this discussion?

Thanks.
SA

"I can do everything on my Mac that I used to do on my PC, plus alot more ..."

-Me

------------------------------------------------------------
Free, BeOS-friendly email accounts: http://BeMail.org/
BeOS News and Community: http://www.BeGroovy.com/

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