how to assign path to a variable in python code example

Example 1: edit path variable using python

app_path = os.path.join(root_path, 'other', 'dir', 'to', 'app')
os.environ["PATH"] += os.pathsep + app_path

Example 2: add python to path

# On linux
$ which python; # Get Path of the executable
$ export PATH=$PATH:{PATH_PYTHON}; # but it isn't continue
# ----------------------
$ which python; # Get Path of the executable
export PATH=$PATH:{PATH_PYTHON}; # add in your ~/.bashrc or your ~/.zshrc