AttributeError

Tim Golden tim.golden at viacom-outdoor.co.uk
Mon Jun 28 16:58:07 CEST 2004


Ajay> i have the following code that doesn't work
Ajay> contextForm = 
Ajay>
{"contextName":"test2","contextDescription":"test22","number":"1","contextNa
me1":"test1","contextDescription1":"test11"}

Ajay> if contextForm.has_key("number"):
Ajay>     num=contextForm["number"].value

Ajay> the error i get is
Ajay> AttributeError: 'str' object has no attribute 'value'

Thanks for producing the output. It's clear enough to me
what's going on, but what I'm wondering is: why isn't it
clear to you? Are you maintaining someone else's code, or
are you translating directly from VB?

In this case, you have a dictionary of key-value pairs
called contextForm. A lookup on that dictionary using
"number" as the key will give its corresponding value "1".
Since "1" is a python string, attempting to get its
attribute .value will fail, as it doesn't have one. (Try
doing dir ("1") at a python prompt). Which is what the 
error message is telling you.

Your line should read (something like):

if contextForm.has_key("number"):
  num=contextForm["number"] # note: no .value

Not to appear rude, you might be advised to understand a
little better some of the fundamentals of Python's objects
and structures before continuing with this project. There
are several on-line tutorials and guides for programmers 
and non-programmers. And also, python.org hosts a tutor
mailing list, aimed at people less familiar with Python.

Have a look here:

http://www.python.org/topics/learn/

TJG


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