[Tutor] user-given variable names for objects

[Che M]

> To: tutor at python.org
> From: alan.gauld at btinternet.com
> Date: Thu, 13 Dec 2007 07:53:36 +0000
> Subject: Re: [Tutor] user-given variable names for objects
> 
> 
> "Che M" <pine508 at hotmail.com> wrote 
> 
> > I'm sure this is a classic beginner's topic, 
> 
> Indeed it is, it comes up about once a month or more!
> 
> > I want to assign names to objects based on what a 
> > user inputs so that I can later keep track of them. 
> 
> This is almost never what you want to do, for precisely 
> the reason that you can't keep trackl of them when you 
> stop using the >>> prompt. Insteaed you should probably 
> use a dictionary to collect these user based objects 
> based on their names.
> 
> There is a section  on this in the OOP topic in my tutorial
> 
> > ...In order to do this, I need to give each start time 
> > a name associated with the name of the event.  
> > If there is an "event A" it's start time could be 
> > eventA_start, whereas event B could be called eventB_start
> 
> So create a dictionary called events and access them using
> 
> events['A']
> events['B']
> 
> etc.
> 
> > The problem is, I don't know the "A" part... the user could 
> > choose eventPotato or eventDinosaur.  I won't know in advance.  
> 
> Which is why you can't write code to use variables whose 
> names you don't know when writing the code. That's why putting 
> them in a dictionary is a better solution. You just get the name 
> as a string and use it as a key in the dictionary. Just watch out 
> for duplicate names.
> 
> > I have read that the way to do this properly in Python is with 
> > use of dictionaries, but I haven't found a reference online that 
> > shows how to do it is in a complete way.  Any help is appreciated.
> 
> Check the bank account example in my tutorial, under the 
> section heading "collections of objects".
> 
> HTH,
> 
> -- 
> Alan Gauld
> Author of the Learn to Program web site
> http://www.freenetpages.co.uk/hp/alan.gauld
> 



Thank you, indeed it did help.  For some reason when I was reading
about dictionaries online I got the unfortunate thought that the value
couldn't be a function--glad I was highly incorrect on that one.  I had
also been shy of understanding how to use dictionaries for some reason (fear of hyphens and curly braces?),
but your section and a little trying it out in IDLE makes it seem
do-able.  I'll give it more of a go later and see if I can get things
moving ahead. 


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