Python .. problem

introuble · 12-29-2006, 01:45 PM

I fount it hard to find a good thread title. I hope the code is self explainatory:

Code:

# one.py
variable = "value"

from two import *
if __name__ == '__main__': print_value()

# two.py
def print_value():
    print variable


--
python one.py
Traceback (most recent call last):
  File "one.py", line 4, in ?
    if __name__ == '__main__': print_value()
  File "/home/sybec/test/two.py", line 2, in print_value
    print variable
NameError: global name 'variable' is not defined

dombrowsky · 12-29-2006, 01:59 PM

I don't know python too well, but I do know that its strict about types and definitions. Far more strict than perl or php.

I assume you have to define what "variable" is somehow in two.py. Like an 'extern' in C.

Hko · 12-29-2006, 03:07 PM

Importing two.py into the local name space of one.py makes objects from two.py available inside one.py.

But this does not mean that it also works the other way around. two.py still doesn't know about objects from one.py (like [i]variable[i]).

It is probably possible to do with some 'python trick', but then two.py will depend on one.py. This is not what people want generally, because then doesn't make sense to have seperate modules in the first place.

Or, purhaps this was what you were looking for?

Code:

variable = "value"

from two import *
if __name__ == '__main__': print_value(variable)

Code:

# two.py
def print_value(var):
    print var

ghostdog74 · 12-29-2006, 07:26 PM

Quote:

Originally Posted by introuble

I fount it hard to find a good thread title. I hope the code is self explainatory:

Code:

# one.py
variable = "value"

from two import *
if __name__ == '__main__': print_value()

# two.py
def print_value():
    print variable

The "variable" variable in print_value() goes out of scope once the function returns. use the method HKO provide and it should be fine.

introuble · 12-30-2006, 03:12 AM

The *problem* is that my application has a number of "n" settings which will be used by various functions (some will use "all" the settings, some only a few, some no settings at all). Now.. assuming my settings are:

Code:

set1 = "val1"
set2 = "val2"
set3 = "val3"
...
set4 = "val4"

I don't know how "efficient" it would be to pass "n" settings via arguments to a function. Obviously, if I do this, there's no need for "variable" to be global. I could store the settings in a dictionary.. or make a class which has them as attributes, and add a few methods which manipulate these settings one way or the other. But then, I'd have only one object belonging to this class. So would it be super-flu or something?

Hko · 12-30-2006, 07:45 AM

Quote:

Originally Posted by introuble

I could store the settings in a dictionary.. or make a class which has them as attributes, and add a few methods which manipulate these settings one way or the other.

Good ideas IMHO.

Quote:

Originally Posted by introuble

But then, I'd have only one object belonging to this class. So would it be super-flu or something?

No. That is just fine, if done well.