Question

Just looking at ways of getting named constants in python.

class constant_list:     (A_CONSTANT, B_CONSTANT, C_CONSTANT) = range(3) 

Then of course you can refer to it like so:

constant_list.A_CONSTANT 

I suppose you could use a dictionary, using strings:

constant_dic = {     'A_CONSTANT' : 1,     'B_CONSTANT' : 2,     'C_CONSTANT' : 3,} 

and refer to it like this:

constant_dic['A_CONSTANT'] 

---

My question, then, is simple. Is there any better ways of doing this? Not saying that these are inadequate or anything, just curious – any other common idioms that I’ve missed?

Thanks in advance.

Answer 1

For 2.3 or after:

class Enumerate(object):   def __init__(self, names):     for number, name in enumerate(names.split()):       setattr(self, name, number) 

To use:

 codes = Enumerate('FOO BAR BAZ') 

codes.BAZ will be 2 and so on.

If you only have 2.2, precede this with:

 from __future__ import generators   def enumerate(iterable):    number = 0    for name in iterable:      yield number, name      number += 1 

(This was taken from here)