Hello World
Popen
p405 You can use Python to start other programs on your computer.
"""Open subprocess:
If you open for example calculator program multiple times,
each window is a different process of the application.
Every process can have multiple threads.
Unlike threads, a process cannot read and write another process's variable.
It's like having a separate copy of the program code.
"""
import subprocess
subprocess.Popen('/usr/bin/gnome-calculator')
subprocess.Popen('/usr/bin/gnome-calculator')
# Opens calculator twice
Arguments
p408 Most applications accept a file to open argument.
"""Open subprocess arguments:
Most GUI applications will accept a single argument for a file to be open.
You pass a list as sole argument to Popen()
"""
import subprocess, pathlib, sys
DIR = pathlib.Path(__file__).resolve().parent
"""The wait() method will block until the launched process has terminated.
This is useful to let the user finish with other programs.
"""
A = subprocess.Popen(['/usr/bin/gedit', DIR/'files/A.txt'])
A.wait()
"""Each operating system has a program that is equivalent to double-click
Windows: start / Linux: see
"""
with open(DIR / 'files/B.txt', 'w') as f:
f.write('Hello World!')
B = subprocess.Popen(['/usr/bin/see', DIR / 'files/B.txt'])
B.wait()
➥ Questions
