Stephen Hansen wrote:
On Mon, Dec 21, 2009 at 1:51 PM, W. eWatson <wolftra...@invalid.com> wrote:
Lie Ryan wrote:
On 12/22/2009 6:39 AM, W. eWatson wrote:
Wow, did I get a bad result. I hit Ctrl-P, I think instead of Alt-P, and
No, its not true. A built-in module does not mean its available
everywhere. It means its built into Python itself-- e.g., its directly
linked into the python dll and not a separate file (like most of the
the standard library).
Lots of modules are built-in, but they don't pollute the __builtins__
/ universal namespace. You import them to access them. If you want you
can "from math import *" if you want the math module to fill out your
module namespace (I don't recommend *'s personally, its better to
import symbols explicitly by name)
--S
This has got to be some sort of IDLE issue then. When I run a simple
program. If I open this program in the IDLE editor:
#import math
print "hello, math world."
print cos(0.5)
print sin(0.8)
then I get
print cos(0.5)
NameError: name 'cos' is not defined
OK, >>> dir()
['__builtins__', '__doc__', '__file__', '__name__', 'idlelib']
Fine. I now change the code to include import mat get the same:
print cos(0.5)
NameError: name 'cos' is not defined
Now, >>> dir()
['__builtins__', '__doc__', '__file__', '__name__', 'idlelib', 'math']
>>>
math is now available. so I change cos(0.5) to math.cos(0.5) and get
print sin(0.8)
NameError: name 'sin' is not defined
Fine, it needs math.
dir() is the same.
Now, I go to the script and enter
from math import *
dir is now bulked up with the math functions. I change back math.cos to
cos and the program runs well.
This sort of figures. Apparently, I've added to the namespace by
importing with *.
My point is that I'm betting different results. OK, fine. It appears the
same thing happens with I modify the program itself with from math import *
So IDLE is not clearing the namespace each time I *run* the program.
This is not good. I've been fooled. So how do I either clear the
namespace before each Run? Do I have to open the file in the editor
again each time before trying to Run it? I hope there's a better way.
--
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