Matt Herzog wrote:
On Tue, Oct 20, 2009 at 02:49:53PM +0000, Tiago Saboga wrote:
On Tue, Oct 20, 2009 at 2:44 PM, Matt Herzog <m...@blisses.org> wrote:
Yes, thanks. What failed was the invocation of PIPE. Apparently I had to
explicitly import PIPE from subprocess or python had no clue as to what PIPE
was!
Dare I say, "wtf?" since when fo I have to specify such? Shouldn't importing
the subprocess module make all its methods available? I can't remember having to do this
before.
It is really like any other module. If you just import subprocess, you
can access all its methods and attributes by spelling it out:
import subprocess
handler = subprocess.Popen(['cat'], stdout=subprocess.PIPE,
stdin=subprocess.PIPE)
Or you can import just the names you will use in the global namespace:
from subprocess import Popen, PIPE
handler = Popen(['cat'], stdout=PIPE, stdin=PIPE)
HTH,
It does help. I never knew this. I don't remember seeing this quirk before.
Thanks.
I don't know how much you've used Python, but you were already using
os.popen(). It's the same thing. In order to reference a symbol
defined in another module, you either have to qualify that symbol with
the module name (like the "os." prefix), or use the fancier from xx
import yy statement.
How about if I elaborate a bit:
When you do
import mymodule
you've added exactly one symbol to your "global" namespace, the
symbol mymodule.
If you do
from mymodule import symbol1, symbol2, symbol3
you do the equivalent of three assignment statements, adding three
symbols to your global namespace.
symbol1 = mymodule.symbol1
symbol2 = mymodule.symbol2
symbol3 = mymodule.symbol3
HTH
DaveA
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