Passing multiple lists to subprocess-CodePudding

I have the following python code:

var_b='en'
var_c='cs'
var_d='false'
var_e=str(Path.home())

IDS='TEST_123'

L1 = [1, 2 , 3, 4]
L2 = ['env', L1, f'a={var_b}']
CMD = ['COMMAND']
L3 = [IDS]
L4 = [f'--b {var_b}', f'--c {var_c}']
L5 = [f'--d {var_d}', f'--e {var_e}.xml', L4]

I would like to execute a terminal command using subprocess to make the end command entry on the terminal looks in the combination L2 CMD L3 L5 i.e.

**L2 CMD L3 L5**
env 1 2 3 4 a=en COMMAND TEST_123 --d false --e /path/to/home.xml --b en --c cs

Here is what i have tried:

subprocess.run([*L2, *CMD, *L3, *L5])

But i'm getting this error:

TypeError: expected str, bytes or os.PathLike object, not list

Could someone please suggest how to implement this.

CodePudding user response：

For the case if L2 contains some L6 as and so on, there must be recursion:

var_b='en'
var_c='cs'
var_d='false'
var_e=str("Path.home()")

IDS='TEST_123'

L1 = [1, 2 , 3, 4]
L2 = ['env', L1, f'a={var_b}']
CMD = ['COMMAND']
L3 = [IDS]
L4 = [f'--b {var_b}', f'--c {var_c}']
L5 = [f'--d {var_d}', f'--e {var_e}.xml', L4]

def build_string_recursively(command_list):
    ret = []
    for command in command_list:
        if isinstance(command,list):
            ret =build_string_recursively(command)
        else:
            ret.append(command)
    return ret

print(build_string_recursively(L2 CMD L3 L5))

This also gives desired:

['env', 1, 2, 3, 4, 'a=en', 'COMMAND', 'TEST_123', '--d false', '--e Path.home().xml', '--b en', '--c cs']

CodePudding user response：

The problem is that this unpacking * goes only one level deep. But you want to unpack every level in order to get a flat list. You should do something like this:

import itertools
from pathlib import Path

def flatten_to_strings(l):
    """Flatten a list or tuple, turning the remaining components into strings."""
    if not isinstance(l, (list, tuple)):
        return [str(l)]
    flat = (flatten_to_strings(i) for i in l)
    return list(itertools.chain.from_iterable(flat))

With this and your code, you can do

print(flatten_to_strings([*L2, *CMD, *L3, *L5]))

and it prints

['env', '1', '2', '3', '4', 'a=en', 'COMMAND', 'TEST_123', '--d false', '--e /home/glglgl.xml', '--b en', '--c cs']

Alternatively, you could assemble your lists as you need them to be:

L1 = [str(i) for i in [1, 2, 3, 4]] # so that they are strings
L2 = ['env', *L1, f'a={var_b}']     # unpack L1 early
CMD = ['COMMAND']
L3 = [IDS]
L4 = [f'--b {var_b}', f'--c {var_c}']
L5 = [f'--d {var_d}', f'--e {var_e}.xml', *L4] # unpack L4 early

This way,

print([*L2, *CMD, *L3, *L5])

gives

['env', '1', '2', '3', '4', 'a=en', 'COMMAND', 'TEST_123', '--d false', '--e /home/glglgl.xml', '--b en', '--c cs']

as well.