More about variables

[Steve Holden]

Matthew Hirsch wrote:
> 
> Why create named variables?
> 
> I always thought that having 20 lists saved more space than having one
> list of 20 lists.  Maybe I'm wrong.
> 
> Thanks for your help,
> Matt
> 

First make it work.  *Then* make it work better!

If you have to be this concerned about optimization so early in
your development you must be working in a VERY restricted environment...

Python is great at all kinds of stuff.  Let the language do what it's
good at, and optimize only when performance or resource usage gets the
better of you!

regards
 Steve

> In article <3X3H4.16435$0o4.108310 at iad-read.news.verio.net>,
> culliton at clark.net (Tom Culliton) wrote:
> 
> > What (or maybe what do you think) you are trying to do?  Most likely
> > you would be better off with just a list or tuple if you're dealing
> > with and unknown number of data items.  Not everything needs a name,
> > and there isn't much difference between:
> >
> > v0, v1, v2, v3, v4, v5
> >
> > and
> >
> > v[0], v[1], v[2], v[3], v[4], v[5]
> >
> > Why do you think this variable length collection of data needs
> > individual names?
> >
> > Now, if after consideration there is still some compelling reason to
> > generate names, you can use something like this with a dictionary
> > (possibly the one returned by globals()):
> >
> > v = {}
> > for i in range(number_of_variables):
> >         name = "variable%d" % i
> >         v[name] = []
> >
> > But again, Why?
> >
> > In article <meh9-5C17A0.10445406042000 at news.cit.cornell.edu>,
> > Matthew Hirsch  <meh9 at cornell.edu> wrote:
> > >Hi All,
> > >
> > >Let's say I had something like:
> > >
> > >number_of_variables=int(raw_input('Enter number of variables: '))
> > >
> > >if number_of_variables==1:
> > >   variable1=[]
> > >elif number_of_variables==2:
> > >   variable1=[]
> > >   variable2=[]
> > >elif number_of_variables==3:
> > >   variable1=[]
> > >   variable2=[]
> > >   variable3=[]
> > >elif number_of_variables==4:
> > >   variable1=[]
> > >   variable2=[]
> > >   variable3=[]
> > >   variable4=[]
> > >elif number_of_variables==5:
> > >   variable1=[]
> > >   variable2=[]
> > >   variable3=[]
> > >   variable4=[]
> > >   variable5=[]
> > >else:
> > >   print 'else'
> > >
> > >Is there a more efficient way of doing this? What if I wanted to create
> > >100 variables (lists).  It doesn't make sense to write an if statement
> > >for that many conditions.
> > >
> > >Thanks for your help,
> > >Matt

--
"Bulding information systems just because it's fun."
Steve Holden  sholden at bellatlantic.net  703 716 7275