On Sun, Jan 18, 2009 at 4:37 PM, David <da...@abbottdavid.com> wrote:
> Everything else works + - / but not *
> why?
> thanks
> -david
It works for me.
However, I do have another issue with your code:
> def compute(arg1, arg2, arg3):
> if sys.argv[2] == "+":
> total = add(int(sys.argv[1]), int(sys.argv[3]))
> print total
> elif sys.argv[2] == "-":
> total = sub(int(sys.argv[1]), int(sys.argv[3]))
> print total
> elif sys.argv[2] == "/":
> total = dev(int(sys.argv[1]), int(sys.argv[3]))
> print total
> elif sys.argv[2] == "*":
> total = mul(int(sys.argv[1]), int(sys.argv[3]))
> print total
> else:
> print "oops"
You define this as a function of arg1, arg2 and arg3, but inside the
function you use the 'outer value' of sys.argv[1], sys.argv[2] and
sys.argv[3]. It is very much advisable to use local rather than global
variables inside functions. That way:
* you can re-use the function elsewhere in the program, or even in a
different program
* you can develop the function and the main program semi-independently.
For example, suppose you want to make this part of a larger program,
and change the call "myprogram.py 2 + 3" to "myprogram.py calculate 2
+ 3". In your case, you would have to change all the sys.argv inside
the function. If instead you define the function as:
def compute(arg1, arg2, arg3):
if sys.arg2 == "+":
total = add(int(sys.arg1), int(sys.arg3))
print total
elif sys.arg2 == "-":
total = sub(int(sys.arg1), int(sys.arg3))
print total
elif sys.arg2 == "/":
total = dev(int(sys.arg1), int(sys.arg3))
print total
elif sys.arg2 == "*":
total = mul(int(sys.arg1), int(sys.arg3))
print total
else:
print "oops"
this can be implemented without changing the function at all, you just
need to change
compute(sys.argv[1], sys.argv[2], sys.argv[3])
to
if sys.argv[1].equals("compute"):
compute(sys.argv[2], sys.argv[3], sys.argv[4])
--
André Engels, andreeng...@gmail.com
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