Find System Installed Version That Matches

python programming snippet

def _check_python_version(python_exe, version):
    python_exe = shutil.which(python_exe)
    if python_exe:
        res = subprocess.Popen([python_exe, "--version"], stdout=subprocess.PIPE,
                                stderr=subprocess.PIPE).communicate()

        # python2 writes version to stderr, python>=3.2 writes it to stdout?!
        version_string = res[0] if res[0] else res[1]
        found_version = version_string.decode('utf-8').split()[-1]
        if found_version.startswith(version):
            return python_exe



# try the system installed versions
for exe in ["python", "python3"]:
    python_exe = _check_python_version(exe, target_version)
    if python_exe:
        return python_exe