CODEWITHSUNDEEP
python
NictheDEV
NictheDEV

Reputation: 187

Append negative integer into a list Python

I have already seen this issue but it seems not fit for my specific use case.

I have a file called whitelist where I save a number that indicates a type of device and the ID of such devices. The format is something like 37423 = -212, -210, 276 where, in this case, 37423 is the number of the device type and -212, -210, 276 are the IDs.

Now, I have a code that scans this type of file and adds into a list the IDs:

if not(manufacturedid in whitelist):
    whitelist[manufacturedid] = list()
for d in deviceid:
    tmp_d = re.sub(r'\W+', '', d)
    if not (tmp_d in whitelist[manufacturedid]):
        whitelist[manufacturedid].append(tmp_d)

where manufacturedid is 37423 and tmp_d are -212, -210, 276

My issue is that when it .append(tmp_d) is a negative number, it converts into a positive one and I can't understand why as the tmp_d in the if not statement should be negative as well.

EDIT: I think the issue is in the for d loop as d results always positive

Upvotes: 0

Views: 196

Answers (2)

Daweo
Daweo

Reputation: 36680

You did

tmp_d = re.sub(r'\W+', '', d)

as you are dealing with ASCII text we can say \W is simply [^a-zA-Z0-9_], thus it was also match and remove -, for example

import re
print(re.sub(r'\W+', '', '-212'))

output

212

Read python re built-in module docs, if you want to know more about \W.

Upvotes: 4

Piglet
Piglet

Reputation: 28974

It is not append but re.sub(r'\W+', '', d) that makes tmp_d positive. Debugging helps with such issues. If the output is not what you expect. Check the input first.

Upvotes: 2

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