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+--- Thread: set.difference of two list gives empty result (/thread-37466.html)
set.difference of two list gives empty result - wardancer84 - Jun-14-2022
hi,
i want to get the difference from two list of strings (using sets) but i always get an empty result. funny enough this worked until today and stopped working overnight without me changing something.
the function:
def delete_dead_ips():
# delete ip's that exists in netbox but not in aix registry
aix_reg_list = []
for i in net_info:
address,mask,broadcast,dns_name = i.split('/')
mask_cidr= IPv4Network(address + "/" + mask, strict=False).prefixlen
addr_recalc = address + "/" + str(mask_cidr)
aix_reg_list.append(addr_recalc)
print('items in aix registry list: "%s"' % len(aix_reg_list))
print('items in aix_ips (netbox) list: "%s"' % len(aix_ips))
#print("\n".join(map(str, aix_reg_list)))
#print("\n".join(map(str, aix_ips)))
dead_ips = list(set(aix_ips).difference(set(aix_reg_list)))
print('items in aix registry but not in netbox "%s"' % len(dead_ips))
if dead_ips and aix_reg_list:
logging.info('ips in netbox but not in aix registry removed: "%s"' % ",".join(dead_ips))
for x in dead_ips:
all_ips.remove(x)
aix_ips.remove(x)
try:
bla = nb.ipam.ip_addresses.get(q=x)
result = nb.ipam.ip_addresses.delete([bla])
except pynetbox.core.query.RequestError as e:
logging.error(str(e.error))result:Output:root@nimvie: /root/bin # ./netbox_import.py
2022-06-14 12:56:47,148 [INFO] netbox 3.2 connected
items in aix registry list: "1708"
items in aix_ips (netbox) list: "1710"
items in aix registry but not in netbox "0" -> this is clearly a lie['10.95.0.1/22', '10.95.0.1/22', '10.95.0.1/22', '10.95.0.1/22', '10.95.0.1/22', '10.95.0.1/22', '10.95.0.1/22', '10.95.0.1/22', '10.95.0.1/22', '10.95.0.1/22', '10.95.0.13/22', '10.95.0.119/22', '10.95.0.149/22', '10.95.0.211/22', '10.95.1.14/22', '10.95.1.15/22', '10.95.1.16/22', '10.95.1.18/22', '10.95.1.20/22', '10.95.1.21/22', '10.95.1.25/22', '10.95.1.48/22', '10.95.1.149/22', '10.111.160.6/24', '10.111.160.10/24']any hints welcome, as i dont see a obvious reason for this....
wbr
chris
RE: set.difference of two list gives empty result - deanhystad - Jun-14-2022
Why is it clearly a lie? If all items in aix_reg_list are also in aix_ips, the difference would be an empty set. a.difference(b) returns all items in a that are not in b. It does not include items in b that are not in a.
Maybe there are duplicates. is len(set(aix_ips)) == len(aix_ips)?
If I was trying to understand the problem I might do something like this:
for a in aix_ips:
if a not in aix_reg_list:
print(a)
RE: set.difference of two list gives empty result - wardancer84 - Jun-14-2022
this list contains 2 more items
items in aix_ips (netbox) list: "1710"than this list
items in aix registry list: "1708"so this 2 items should show up in the difference results IMHO
no sure if this is true, but i read somewhere that "sets" do not work well with lists that contain duplicate items which is absolutely the case here.
i tried list comprehensions instead of sets but this all gives empty results also
dead_ips = [item for item in aix_reg_list if item not in aix_ips] dead_ips = [item for item in aix_ips if item not in aix_reg_list]
RE: set.difference of two list gives empty result - deanhystad - Jun-14-2022
Looks like you have duplicates in aix_ips.
RE: set.difference of two list gives empty result - wardancer84 - Jun-14-2022
this diff method can handle duplicates...works well at first sight
from collections import Counter ... dead_ips = list((Counter(aix_ips) - Counter(aix_reg_list)).elements()) # get list of whats in the first list but not in the secondmission completed