looping external commands in python

Question

I'm trying to run a simple set of command line calls to a custom app, within a loop.

i.e.

list=['set1','set2','set3','set4']
ExternCmd = (myapp + ' ' + arg1 + ' ' + arg2 ' -v ')
for item in list:
    arg1 = item
    self.process.start(ExternCmd)
    self.process.waitForFinished(-1)

But I dont get sets 2 - 4 processed, only the first.

I tried adding a self.process.join() to get the loop to wait for the current set to finish processing,but I get the following error:

AttributeError: 'QProcess' object has no attribute 'join'

any help would be great getting my processes to work in order. I would ideally like them to be processed one after the other - rather than all at the same time.

thanks

EDIT: I put the ExternCmd in the wrong place for this example. My code should be:

list=['set1','set2','set3','set4']
for item in list:
    arg1 = item
    ExternCmd = (myapp + ' ' + arg1 + ' ' + arg2 ' -v ')

    self.process.start(ExternCmd)
    self.process.waitForFinished(-1)

This is still failing to run the command on anything other than Set1

The code is incorrect arg2 ' -v ' is invalid syntax. Post real non-working code. See mcve. — Open AI - Opting Out
– Open AI - Opting Out, Commented Oct 6, 2015 at 14:11

Ryan · Accepted Answer · 2015-10-05 14:26:29Z

1

Changing the args isn't changing ExternCmd. You need to set that in the loop, for example:

list=['set1','set2','set3','set4']
for item in list:
    ExternCmd = (myapp + ' ' + item + ' -v ')
    self.process.start(ExternCmd)
    self.process.waitForFinished(-1)

answered Oct 5, 2015 at 14:26

Ryan

2,0942 gold badges17 silver badges33 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

sjm1983 Over a year ago

oops, in my haste to write a simple example I put ExternCmd outside of the loop. In my actual code it is inside - I'll update my original post

Collectives™ on Stack Overflow

looping external commands in python

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related