如果数字 output 显示为字符串，如何匹配 IF 语句中的数字范围？

Question

I am a.network engineer by day learning python to automate tasks, please go easy as I am a python newbie. My goal is to iterate through a range of switchport interfaces and identify down switchport interfaces, then apply a new VLAN ID to the port.

The first stage of my script is below, which presents me with a list of down ports.

The issue I am facing is that I am wanting to over iterate over port numbers 3-6, 38-52 and that are down.

At present I am iterating through the entire list of ports identified on the switch.

import netmiko

from netmiko import ConnectHandler
from getpass4 import getpass

user = 'example_user'
password = getpass('Password: ')

net_connect = ConnectHandler(
    device_type="hp_procurve",
    host="10.0.0.1",
    username= user,
    password= password,
)

print('*** Sending command ***')

show_int_brief = net_connect.send_command("show int brief", use_textfsm=True)

net_connect.disconnect()

int_down = []
for item in show_int_brief:
    if item['status'] == 'Down':
        int_down.append(item['port'])

print('*** Port status known as down ***\n', int_down)

Example output prior to being added to the list int_down.

[{'port': '1', 'type': '100/1000T', 'intrusion_alert': 'No', 'enabled': 'Yes', 'status': 'Up', 'mode': '1000FDx', 'mdi_mode': 'MDI', 'flow_ctrl': 'off', 'bcast_limit': '0'},
 {'port': '2', 'type': '100/1000T', 'intrusion_alert': 'No', 'enabled': 'Yes', 'status': 'Up', 'mode': '1000FDx', 'mdi_mode': 'MDIX', 'flow_ctrl': 'off', 'bcast_limit': '0'},
{'port': '3', 'type': '100/1000T', 'intrusion_alert': 'No', 'enabled': 'Yes', 'status': 'Down', 'mode': '1000FDx', 'mdi_mode': 'Auto', 'flow_ctrl': 'off', 'bcast_limit': '0'}, 
{'port': '4', 'type': '100/1000T', 'intrusion_alert': 'No', 'enabled': 'Yes', 'status': 'Down', 'mode': '1000FDx', 'mdi_mode': 'Auto', 'flow_ctrl': 'off', 'bcast_limit': '0'}, 
{'port': '5', 'type': '100/1000T', 'intrusion_alert': 'No', 'enabled': 'Yes', 'status': 'Down', 'mode': '1000FDx', 'mdi_mode': 'Auto', 'flow_ctrl': 'off', 'bcast_limit': '0'}, 
{'port': '6', 'type': '100/1000T', 'intrusion_alert': 'No', 'enabled': 'Yes', 'status': 'Down', 'mode': '1000FDx', 'mdi_mode': 'Auto', 'flow_ctrl': 'off', 'bcast_limit': '0'}]

And so on..

Example output after being placed in 'int_down' and printed.

Numbers identified are expected, as these are in a down state.

['3', '4', '5', '6', '7', '8', '9', '30', '31', '32', '33', '34', '35', '36', '37', '38', '39', '40', '41', '42', '43', '44', '45', '47', '49', '50', '51', '52']

The idea is to then use this list in another command that will proceed with applying VLAN configuration only to these ports, though will tackle this as I get past this hurdle.

Cheers,

Luppa

Answer 1

I don't think it is worth to limit to a range a priory, since ensuring the port data is in the proper shape and organization would be similar or even more computational effort with respect to looping through all ports directly. Instead I suggest to filter ad-hoc:

I use the boild down list of ports-dicts:

ports = [
    {'port': '1', 'status': 'Down'},
    {'port': '7', 'status': 'Down'},
    {'port': '2', 'status': 'Up'},
    {'port': '8', 'status': 'Up'},
    {'port': '4', 'status': 'Down'},
    {'port': '5', 'status': 'Up'},
    {'port': '9', 'status': 'Up'},
    {'port': '6', 'status': 'Down'}
]

Please note that they are not in order and have missing entries to simulate real world data more closely.

Then first I implement a helper function, where I can specify the ranges of interest. If these are more than two consider to use any() and a list of ranges for readability.

def of_interest(port_num: int) -> bool:
    return port_num in range(3, 7) or port_num in range(38, 53)

Now your nested for and if structure can be expressed as list comprehension :

down_ports = [e['port'] for e in ports if e['status'] == 'Down' and of_interest(int(e['port']))]

Of course, depending on what you want to do in later steps it might make sense to copy all values from the port list of that entry.

Does this help?