List comprehension in python error?

Question

I want to get the result of nmcli (linux) in a 3D list in python.

The sample output of nmcli device show is

GENERAL.DEVICE: wlan0
GENERAL.TYPE: wifi
GENERAL.HWADDR: :::::
GENERAL.MTU: 1500
GENERAL.STATE: 100 (connected)
GENERAL.CONNECTION:
GENERAL.CON-PATH: /org/freedesktop/NetworkManager/ActiveConnection/2
IP4.ADDRESS[1]: 192.168.1.106/16
IP4.GATEWAY: 192.168.1.1
IP4.ROUTE[1]: dst = 0.0.0.0/0, nh = 192.168.1.1, mt = 600
IP4.ROUTE[2]: dst = 192.168.0.0/16, nh = 0.0.0.0, mt = 600
IP4.DNS[1]: 192.168.1.1
IP6.ADDRESS[1]: :::::::/
IP6.ADDRESS[2]: :::::/
IP6.GATEWAY: :::::
IP6.ROUTE[1]: dst = :::::/, nh = ::, mt = 600
IP6.ROUTE[2]: dst = ::/0, nh = fe80::30ae:bfff:fe20:64d, mt = 600
IP6.ROUTE[3]: dst = ::/, nh = ::, mt = 256, table=255
IP6.ROUTE[4]: dst = ::/, nh = ::, mt = 256
IP6.ROUTE[5]: dst = ::/, nh = ::, mt = 600
IP6.DNS[1]: :::::
IP6.DNS[2]: :::::::

GENERAL.DEVICE: eth0
GENERAL.TYPE: ethernet
GENERAL.HWADDR: :::::
GENERAL.MTU: 1500
GENERAL.STATE: 20 (unavailable)
GENERAL.CONNECTION: --
GENERAL.CON-PATH: --
WIRED-PROPERTIES.CARRIER: off

GENERAL.DEVICE: lo
GENERAL.TYPE: loopback
GENERAL.HWADDR: 00:00:00:00:00:00
GENERAL.MTU: 65536
GENERAL.STATE: 10 (unmanaged)
GENERAL.CONNECTION: --
GENERAL.CON-PATH: --
IP4.ADDRESS[1]: 127.0.0.1/8
IP4.GATEWAY: --
IP6.ADDRESS[1]: ::1/128
IP6.GATEWAY: --

As you can see there are three interfaces : wlan0 , eth0 and lo. I want a list of columns in a list of rows in a list of interfaces (3D).

I used subprocess to get the result

r1 = subprocess.run(['nmcli', 'device', 'show'], stdout=subprocess.PIPE)
r2 = [y.split() for y in [z.split('\n') for z in r1.split('\n\n')]]

But I get the following error

  File "<stdin>", line 1, in <module>
  File "<stdin>", line 1, in <listcom>
AttributeError: 'list' object has no attribute 'split'

Any suggestions?

PS: I ran that on python 3.6.3 shell

Answer 1

The result of [z.split('\\n') for z in r1.split('\\n\\n')] is a list of lists, so when you iterate over it you are trying to split a list instead of a string. The error is in y.split() .

I think what you want is:

r2 = [[y.split() for y in z.split('\n')] for z in r1.split('\n\n')]