Python-list Digest, Vol 27, Issue 123

[Fredrik Lundh]

Michael Williams wrote:

> Thanks, Heiko, I'll give this a try.  In the meantime, I'll try to
> explain what exactly I mean.
>
> Basically, I want the ability to reference a variable just as I am
> able to set a variable (or attribute) on the fly.  For instance, say
> the user has the following list in a text file:
>
> [butter, cream, eggs, toast, jam]

list of what?  what's butter?  a variable?  a string?  did you mean

    ["butter", "cream", "eggs", "toast", "jam"]

or did you mean something else?  (probably something else, since
whatever the user has put in the text file seems to have a value
property in your later examples).

> I want to be able to loop through that and say the following:
>
> item.__setattr__(list[0].value,myclass())

that's spelled

    setattr(item, list[0].value, myclass())

in python.

to add attributes for all items in the list, do:

    for v in list:
        setattr(item, v.value, myclass())

if the list contains strings, you can simply do:

    for v in list:
        setattr(item, v, myclass())

> At that point I have  item.butter, but I don't want to have to know
> (or hardcode) this, I want to then be able to do the following:
>
> item.__getattr__(list[0].value).__setattr__(list[1].value)

so the list is in fact a path?  how about

    this = item
    for v in list[:-1]:
        this = getattr(this, v)
    setattr(this, list[-1], myclass())

hope this helps!

</F>