Was feeling smug thinking that I had the best lambda expression in the universe cooked up to return all the relevant network information ever needed using python and netifaces
>>> list(map(lambda interface: (interface, dict(filter(lambda ifaddress: ifaddress in (netifaces.AF_INET, netifaces.AF_LINK), netifaces.ifaddresses(interface) ))) , netifaces.interfaces()))
but I got this
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 1, in <lambda>
TypeError: cannot convert dictionary update sequence element #0 to a sequence
scaling it back a bit
>>>dict(filter(lambda ifaddress: ifaddress in (netifaces.AF_INET, netifaces.AF_LINK), netifaces.ifaddresses("eth0")))
is where the problem is:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: cannot convert dictionary update sequence element #0 to a sequence
but so I can convert the filter object to a list
>>> list(filter(lambda ifaddress: ifaddress in (netifaces.AF_INET, netifaces.AF_LINK), netifaces.ifaddresses("eth0")))
[17, 2]
but, that's not what I want. I want what it actually is:
>>> netifaces.ifaddresses("tun2")
{2: [{'addr': '64.73.0.0', 'netmask': '255.255.255.255', 'peer': '192.168.15.4'}]}
>>> type (netifaces.ifaddresses("eth0"))
<class 'dict'>
so what's mucking up my cast back back to dictionary?
When given a dictionary as input, filter
will only iterate and return the keys from that dictionary.
>>> filter(lambda x: x > 1, {1:2, 3:4, 5:6})
[3, 5]
Thus you are feeding just the sequence of filtered keys into the new dict, not the key-value-pairs. You could fix it like this: Note the call to items()
and how the inner lambda
is getting a tuple as input.
list(map(lambda interface: (interface, dict(filter(lambda tuple: tuple[0] in (netifaces.AF_INET, netifaces.AF_LINK),
netifaces.ifaddresses(interface).items()))),
netifaces.interfaces()))
Now that's not very pretty... I suggest changing your code to a nested list- and dictionary-comprehension:
[(interface, {ifaddress: value
for (ifaddress, value) in netifaces.ifaddresses(interface).items()
if ifaddress in (netifaces.AF_INET, netifaces.AF_LINK)})
for interface in netifaces.interfaces()]