How to extract data from a single column list and generate another?

Question

Good morning. I’m new to programming and I started out with curiosity and the need to eliminate some repetitive functions from my day to day.

I am creating a code that enters a network equipment (netmiko library), gives a command and picks up the return of it. The output is something similar to the one shown below, always comes 1 line with 'Underlying Interface: ' and another with 'Stacked VLAN Id: 0x8100.'.

1 - What I tried and am not getting is to delete these words leaving only 'Xe-1/0/6' and '2847' for all lines. When I ran two separate if, I was able to delete the words leaving only what I want, but only for the first appearance.

I tried to do it with a go, but I can’t get an answer.

2 - After I can do step 1, I need to organize the data in column 1 (all appearances that have Xe - odd lines) and column 2 ( all appearances that have the last 4 numbers ex:2847 - even lines)

output returns that list that can have 500 lines or up to 120 thousand:
output=
Underlying Interface: Xe-1/0/6
Stacked VLAN Id: 0x8100.2847
Underlying Interface: Xe-1/0/7
Stacked VLAN Id: 0x8100.2842
Underlying Interface: Xe-1/0/9
Stacked VLAN Id: 0x8100.2862

output = connection.send_command(command)

for p in range(0, len(output), 1):
     if '0x8100.' in output[p]:
         vlan = output[p]
         vlan = vlan[vlan.find('0x8100')+7:vlan.find('0x8100')+11]
         print(vlan)

     if 'Interface' in output[p]:
        interface = output[p]
        interface = interface[interface.find('Interface') + 11:interface.find('Interface') + 19]
        print(interface)

final result I am seeking:
Xe-1/0/6 2847
Xe-1/0/7 2842
Xe-1/0/9 2862

---

Edit 1: The answer brings only the first appearance: ['Xe-1/0/6'], ['2847']] The ouput data is obtained from the response of a network equipment, so I forced them into a string and put them in a list. Below follows the code just hiding the data from the equipment and password.
Complete output list: https://drive.google.com/open?id=12qq5P0DqFWheCDuNW6wTP4M7qkjT1HtV

import netmiko
import time

start = time.time()

connection = netmiko.ConnectHandler(ip='100.100.100.100',device_type='juniper_junos',username='teste',password='teste')
command = 'show subscribers client-type vlan detail | match "^Underlying Interface\:|^Stacked VLAN Id"'

outputA = connection.send_command(command)
outputB = str(outputA)
output = [outputA]

connection.disconnect()

result = [[], []]
for p in range(len(output)):
    if '0x8100.' in output[p]:
        result[1].append(output[p][output[p].find('0x8100')+ 7 : output[p].find('0x8100') + 11])
    if 'Interface' in output[p]:
        result[0].append(output[p][output[p].find('Interface') + 11 : output[p].find('Interface') + 19])

print(result)

end = time.time()
print('Tempo de execução: {} segundos'.format((end - start)))

Python response: ['Xe-1/0/6'], ['2847']]
Running time: 6.372122049331665 seconds

---

Edit 2 - print showing outputA class and outputA print

Answer 1

I managed to get to that code for your problem:

result = [[], []]
for p in range(len(output)):
    if '0x8100.' in output[p]:
        result[1].append(output[p][output[p].find('0x8100')+ 7 : output[p].find('0x8100') + 11])
    if 'Interface' in output[p]:
        result[0].append(output[p][output[p].find('Interface') + 11 : output[p].find('Interface') + 19])

print(result)

1. You were assigning the string "clean" always to the same variable, so at each iteration you erased the old value and put a new one in place. So to store all the values, you should put this in a list. The method append() list, add the value you pass to it at the end of the list.
2. Since you need two "columns", from to use a list that contains 2 other lists inside, one for column 1 and the other for column 2. To access a value, you use for example: result[0][0], ( value of first row and first column).

EDIT 1:

Whereas the return of the function connection is a huge string, so you need to break it into a list, for the method I suggested to work. I believe you can do it this way:

outputA = connection.send_command(command)
output = outputA.split('\n')

Using the method split in the outputA, with the separator parameter \n, you break the string in the "line breaks", returning you a list with each line. Then you can pass the output for the code I indicated. I hope it works this time.

Answer 2

Hello, first of all welcome.

I would advise that the next time you ask a question leave all the source code you are using because it would be better to assist knowing fully what it is, I will try to help the way I can with the information you have given us.

You will need to make an important change to your code, try to run the code below from your original code the first one posted with these modifications.

output = connection.send_command(command)

listaObjetos = []

for i in output:
    listaObjetos.append(i)

def categorizar(outputList):
    UnderlyingList = []
    StackedList = []
    joinList = []
    for Under in outputList:
        if 'Underlying' in Under:
            UnderlyingList.append(Under.replace('Underlying Interface: ', ''))
        else:
            pass
    for Stacked in outputList:
        if 'Stacked' in Stacked:
            StackedList.append(Stacked.replace('Stacked VLAN Id: 0x8100.', ''))
        else:
            pass
    for count in range(len(UnderlyingList)):
        joinList.append('{} {}'.format(UnderlyingList[count], StackedList[count]))
    return joinList

for item in categorizar(listaObjetos):
    print(item)

As I do not have access to the original output I did a simulation but you should take the output and add each item directly to a list WITHOUT PROCESSING ANYTHING.

I tested the code by simulating its output in list form and it worked:

output = ['Underlying Interface: xe-1/0/6', 'Stacked VLAN Id: 0x8100.2847', 
            'Underlying Interface: xe-1/0/7', 'Stacked VLAN Id: 0x8100.2842', 
            'Underlying Interface: xe-1/0/9', 'Stacked VLAN Id: 0x8100.2862']

def categorizar(outputList):
    UnderlyingList = []
    StackedList = []
    joinList = []
    for Under in outputList:
        if 'Underlying' in Under:
            UnderlyingList.append(Under.replace('Underlying Interface: ', ''))
        else:
            pass
    for Stacked in outputList:
        if 'Stacked' in Stacked:
            StackedList.append(Stacked.replace('Stacked VLAN Id: 0x8100.', ''))
        else:
            pass
    for count in range(len(UnderlyingList)):
        joinList.append('{} {}'.format(UnderlyingList[count], StackedList[count]))
    return joinList

for item in categorizar(output):
    print(item)

my output was:

xe-1/0/6 2847
xe-1/0/7 2842
xe-1/0/9 2862