scanning for numerals / letters

[johnzenger at gmail.com]

First, note that form["date"] is all you need.  form["date"].value is
redundant.

I would do this with sets:

import string
if set(form["date"]) & set(string.ascii_letters) != set([]): print "You
have to enter a date with numbers"

if set(form["purchases"]) & set(string.digits) != set([]): print
"Please do not use numbers"

Sets take time to construct, but they test membership faster than
strings.  Plus, the code just reads logically.  (The &, if you couldn't
figure it out, does an intersection of sets.  You could also use the
.intersection method for even better readability).