Request Help With Function
MRAB
python at mrabarnett.plus.com
Mon Apr 4 16:02:53 EDT 2016
On 2016-04-04 20:42, Wildman via Python-list wrote:
> I am working on a Linux gui program where I want to be able
> to click a Help button and open a man page using a viewer.
> I wrote a search function that can be called several times,
> if needed, with different arguments. I wrote a test program
> that tries to open the Bash man page in a terminal and will
> display a message box if the search fails. It passes the
> system path, terminal emulators and command line arguments
> to the search function. I appears that you can't pass a list
> to a function so I am passing the arguments as strings and then
> converting them to lists for parsing in the search function.
>
> When I run the test program, I get this error:
>
> Traceback (most recent call last):
> File "./man.py", line 38, in <module>
> launch_help()
> File "./man.py", line 10, in launch_help
> if search(pathlist, executelist, commandlist):
> File "./man.py", line 27, in search
> subprocess.Popen(command)
> File "/usr/lib/python2.7/subprocess.py", line 710, in __init__
> errread, errwrite)
> File "/usr/lib/python2.7/subprocess.py", line 1335, in _execute_child
> raise child_exception
> TypeError: execv() arg 2 must contain only strings
>
> I have not been able to figure out why I'm getting the error.
> Any help would be appreciated. Below is the complete code for
> the test program:
>
> #!/usr/bin/env python
>
> import os, subprocess, tkMessageBox
>
> def launch_help():
> pathlist = os.environ["PATH"]
> executelist = "xvt,xfce4-terminal"
> commandlist = "-e,man bash"
> if search(pathlist, executelist, commandlist):
> return None
> message = "Open a terminal and enter: man bash"
> tkMessageBox.showinfo("Help", message)
>
> def search(pathlist, executelist, commandlist):
> pathlist = pathlist.split(":")
> executelist = executelist.split(",")
> commandlist = commandlist.split(",")
> done = False
> for path in pathlist:
> for execute in executelist:
> target = path + "/" + execute
> if os.path.isfile(target):
> done = True
> command = [target, commandlist]
> subprocess.Popen(command)
> if done:
> break
> if done:
> break
> if done:
> return True
> else:
> return False
>
>
> launch_help()
>
.Popen will accept either a string or a list of strings.
You're giving it a list that contains a string and a list.
BTW, I don't know what you mean by "you can't pass a list to a
function", because you can. How were you trying to do it?
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