how to change os.popen4 to subprocess

2012-10-26 Thread skyworld 
Hi,

I'm new to python and I'm trying to porting some scripts from v0.96 to
v2.0.1. A piece of code is like this:

cmd_h = os.popen4(env['SYSCMDLINE'])[1]

the system indicates the popen4 is deprecated and suggest to use
subprocess. Can anybody tell me how to use subprocess in this case?
and what does "[1]" here means?

thanks.
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Re: how to change os.popen4 to subprocess

2012-10-26 Thread skyworld 
On Oct 27, 11:02 am, MRAB  wrote:
> On 2012-10-27 03:28, skyworld wrote:> Hi,
>
> > I'm new to python and I'm trying to porting some scripts from v0.96 to
> > v2.0.1. A piece of code is like this:
>
> > cmd_h = os.popen4(env['SYSCMDLINE'])[1]
>
> > the system indicates the popen4 is deprecated and suggest to use
> > subprocess. Can anybody tell me how to use subprocess in this case?
> > and what does "[1]" here means?
>
> os.popen4 returns a tuple of (child_stdin, child_stdout_and_stderr).
> The [1] gets the child_stdout_and_stderr member.
>
> Using the subprocess module:
>
> # Untested!
> cmd_h = subprocess.Popen(env['SYSCMDLINE'], stdout=subprocess.PIPE,
> stderr=subprocess.STDOUT, shell=True).stdout
>
> Explanation:
>
> The command line: env['SYSCMDLINE']
>
> Return stdout: stdout=subprocess.PIPE
>
> stderr should be combined with stdout: stderr=subprocess.STDOUT
>
> Let the shell parse the command line: shell=True

thanks
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question on subprogram parameter

2012-10-28 Thread skyworld 
Hi,

I'm studying python now and I saw a piece of code like this:

def storeDbase(db, dbfilename=dbfilename):
 .
 dbfile=open(dbfilename,'w')
 for key in db:
  print(key, file=dbfile)


can anybody help me to understand what does this "file=dbfile" mean
and what is its function? thanks.
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functon invoke or not

2013-01-09 Thread skyworld 
Hi,

I see someone's code as this:

class ABC: 
def __init__(self, env):
 ...
 self.jmpTable['batchQ']['submit_job']  = self.lsf_submit
 ...
def lsf_submit(self, cmd,env):
 .

what confused me is why there is no parentheses for self.lsf_submit in
"self.jmpTable['batchQ']['submit_job']  = self.lsf_submit"? what does
this piece of code mean? thanks.
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Re: functon invoke or not

2013-01-09 Thread skyworld 
On 1月9日, 下午4时46分, Mitya Sirenef  wrote:
> On Wed 09 Jan 2013 03:23:56 AM EST, skyworld wrote:
>
> > Hi,
>
> > I see someone's code as this:
>
> > class ABC: 
> >      def __init__(self, env):
> >           ...
> >           self.jmpTable['batchQ']['submit_job']  = self.lsf_submit
> >           ...
> >      def lsf_submit(self, cmd,env):
> >           .
>
> > what confused me is why there is no parentheses for self.lsf_submit in
> > "self.jmpTable['batchQ']['submit_job']  = self.lsf_submit"? what does
> > this piece of code mean? thanks.
>
> Presumably it will be called at a later point:
>
> def f(): print 'foo'
>
> lst = [f]
> # la la
> lst[0]()
>
> HTH,  -m
>
> --
> Lark's Tongue Guide to Python:http://lightbird.net/larks/

Thanks for both of your replies. I got it.
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