[Tutor] Sys.argv read parameters

[Dave Angel]

On 04/17/2013 03:27 PM, Danilo Chilene wrote:
> Dear Python Tutor,
>
> I have the code below(file.py):
>
> import sys
>
> a = 'This is A'
> b = 'This is B'
> c = 'This is C'
>
> for i in sys.argv[1]:
>      if sys.argv[1] == 'a':
>          print a
>      if sys.argv[1] == 'b':
>          print b
>      if sys.argv[1] == 'c':
>          print c

Since this is a loop, I'll assume that argv[1] was supposed to permit 
multiple characters.  If so, your loop is buggy.  And if not, then you 
don't want a loop.

>
> I run python file.py a and returns the var a, so far so good.

What do you want to happen if you say
       python file.py  ac


>
> The problem is that i have a bunch of vars(like a to z), how I can handle
> this in a pythonic way?
>

Use a dictionary (dict).  Instead of separate 'variables' use one dict. 
  (With version 2.7)

import sys

mystrings = { "a" : "This is A",
               "b" : "This is B",
               "c" : "This is C",
               "d" : "This is some special case D",
             }

for parm in sys.argv[1]:
     if parm in mystrings:
         print mystrings[parm]
     else:
         print "Invalid parm"

If this isn't what you wanted, then you'll have to make it clearer.

1) tell us what version of python
2) supply us with a non-buggy program,
3) be much more specific about what change you want.  You don't want 
more vars, you presumably want a way to avoid having more vars.  Danny 
assumed you wanted those exact strings, for a, b, and c, while i assumed 
that those were just simple examples.


-- 
DaveA