Before being able to see 3rd answer, I did something like this and it
worked for me:
#!/usr/bin/env python
# -*- encoding:utf-8 -*-
def command_dispatcher():
"Takes comman line arguments and executes regardin method"
command = raw_input(">>>")
args = command.split(" ")
query_string = ".".join(args[0:2])
method_args = ",".join(args[2:])
try:
exec query_string+"("+method_args+")"
except NameError:
print "You are trying to get somethin that is not exist!"
class calculate:
@staticmethod
def bundle():
print "your best bundle is -->"
command_dispatcher()
But after reading 3rd answer regarding the danger of exec, I had my
doubts, Now I will try to implement what second person said about
getattr, and will return here with result.
And What I want to do is a small economy application. It will work this way:
user add a product name, rate how much it like it over 10, and enter its
price.
[repeated as many times as wanted]
user will enter h(is|er) budget.
user will use "calcute bundle" to show much of each product s?he should buy
user will repeat any step as long as s?he likes.
15-03-2011 00:14, Steven D'Aprano yazmış:
Yaşar Arabacı wrote:
Hi
I am trying to do something like this:
If you are trying to write a mini-language, the ``cmd`` and ``shlex``
modules in the standard library may be useful to you.
#!/usr/bin/env python
def command_dispatcher():
"Takes comman line arguments and executes regardin method"
command = raw_input(">>>")
args = command.split(" ")
args[0].args[1]
The error you get tells you exactly what is wrong:
AttributeError: 'str' object has no attribute 'args'
When you split the line, you get a list of strings. You extract the
first string using args[0], and then look up the attribute "args" on
that string, and finally look up the second element of that result. But
strings don't have an attribute called args.
Try this instead:
getattr(args[0], args[1])
When you do that, you'll run into a bunch of new and exciting errors,
starting with the fact that nothing appears to happen. Try it and see.
What you will eventually need to do is:
* create a class instance and store it somewhere
* call the method on the class instance
* print its output
none of which is yet done by your script. So far, all it does it try to
look up a method on a class, then throw the result away without doing
anything :)
class calculate:
def bundle(self):
print __class__
command_dispatcher()
calculate.bundle won't do anything except fail, because __class__ is not
a local variable.
It's better to have the methods return a result, rather than print, and
then have the command_dispatcher responsible for printing it. That lets
you chain methods to make more powerful functions.
Good luck, and have fun!
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