Nested for

Loops for can be nested in each other.

In this example, commands is a list of commands to execute on each interface in the fast_int list:

In [7]: commands = ['switchport mode access', 'spanning-tree portfast', 'spanning-tree bpduguard enable']
In [8]: fast_int = ['0/1', '0/3', '0/4', '0/7', '0/9', '0/10', '0/11']

In [9]: for intf in fast_int:
   ...:     print('interface FastEthernet {}'.format(intf))
   ...:     for command in commands:
   ...:         print(' {}'.format(command))
   ...:
interface FastEthernet 0/1
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
interface FastEthernet 0/3
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
interface FastEthernet 0/4
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
...

The first for loop passes through interfaces in the fast_int list and the second through commands in commands list.