Var substitution

[Jeff Epler]

Guy,
"A good FORTRAN programmer can program FORTRAN in any language."
    -- Allen Brown.

You're asking questions about how to do things in Python that, while
possible, are not idiomatic.  It sounds like you're probably coming from
background in another language or trying to directly translate a program
written in another language.

While people are giving you good answers about how to do the things
you're asking about, I suspect that you would be better off in the long
run learning to write Python programs than to write programs for
language XXX in Python.

Jeff