🔒 Regex help

[steel pollen]

Im not sure how to get 255 accepted

import re
import sys


def main():
    print(validate(input("IPv4 Address: ")))

def validate(ip):
    return re.search(r'[0-2][0-5][0-5]\.[0-2][0-5][0-5]\.[0-2][0-5][0-5]\.[0-2][0-5][0-5]', ip)



if __name__ == "__main__":
    main()

[proper quartz]

@steel pollen

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[steel pollen]

im new to regex

[robust rampart]

It looks like your regex will accept 255 fine (unless I missed a typo or something). What it won't accept are two-digit numbers, which is why it won't accept 10 (it would accept 010 though). It also won't accept numbers where the second or third digit are greater than 5 (so no 199 and 246). You can fix all that by spelling out all the possible forms of numbers between 0 and 255, but honestly I think it will be easier to just validate that you have four sequences of 1-3 digits separated by dots and then split on . and convert to int to validate that the numbers are in range.

[topaz cove]

What if i type 1.2.3.4

[steel pollen]

ok i got most of that but im not sure how to get those sequences

should i use groups?

then convert to ints

[steel pollen]

ill try

[robust rampart]

On another note, it seems weird that your function is called validate, but what it seems to be doing is to search for an IP in the given string.

[steel pollen]

gets none

[topaz cove]

I mean stress test that regex. Its gonna be hard 😔

[steel pollen]

it should return true or false if its a valid ip

[robust rampart]

But search doesn't return true or false. It returns a match or None. And to return a match, the given string only needs to contain a match. It doesn't have to match the regex in its entirety.

[steel pollen]

yea i know I can do if statments after to check

[steel pollen]

oh didnt know the last part

[robust rampart]

For example, if you input "This text contains the IP 255.255.255.255 haha", then your current code will output "255.255.255.255".

[steel pollen]

should i use matchfull?

[robust rampart]

If that's not what you want, you want to us fullmatch, not search.

Yes, exactly.

[steel pollen]

ok sure

now i keep getting none

import re
import sys


def main():
    print(validate(input("IPv4 Address: ")))

def validate(ip):
    return re.fullmatch(r'[0-2][0-5][0-5]\.[0-2][0-5][0-5]\.[0-2][0-5][0-5]\.[0-2][0-5][0-5]$', ip)



if __name__ == "__main__":
    main()

any advice?

[robust rampart]

As I said, your current regex will not match any numbers with less than three digits (also any number with the digits six through 9 in them).

[broken jacinth]

read this message again :p

[steel pollen]

oh

yes it does

[jagged turtle]

Right now you're matching for range 0-2 exactly one time

Either change to [0-255] or use [0-2]?[0-5]?[0-5]?

-# Its been a bit since ive used builtin re

[steel pollen]

[0-255] is rejected in my code

i want to take numbers 0-255

[jagged turtle]

noted, try the other option

[robust rampart]

[0-255] is another way to write [0125]. That will not do what you want.

[jagged turtle]

Regex101 is your best friend

[broken jacinth]

if you don't mind getting spoiled an answer, check this stack overflow post

[steel pollen]

latter doesnt work either

[robust rampart]

Note that [0-2]?[0-5]?[0-5]? will match the empty string (and will still not match 199). I still stand by my earlier suggestion to work with ints instead of regexes to validate the range.

[steel pollen]

hmm ok

should I split it then

[jagged turtle]

This also wont catch all ips

Split it and do numeric comparison on each int

192.168.0.1 is a valid NAT IP and would fail that regex even if it was working

[robust rampart]

On an unrelated note, be aware that some tools and APIs interpret leading 0s as indicating octal numbers, so you might not want to allow leading 0s in the IP depending on what you want to do with it.

[steel pollen]

ah yes ik but for my assignment its fine and i can ignore leading 0s

[jagged turtle]

You should be able to search online for common IP regex algorithms if you're confused

[steel pollen]

i dont understand half of it tho lol

[jagged turtle]

Use something called Regex 101

https://regex101.com/

Try out regex here and it has an explaination tab on the side. It also comes with a quick reference guide

[steel pollen]

Thanks!

[jagged turtle]

All you gotta do is make sure you have the python flavour selected otherwise the regex may be slightly different

[golden jasper]

You code just described
I need 0-2 for first number, 0-5 for second number and 0-5 for the third number

[steel pollen]

just one last question, how abouts do i check for the first byte? I treid this:

from numb3rs import validate

def test_first():
    assert validate("512.512.512.512") == False
    for i in "255":
        if validate(f"{i}.1.1.1") == False:
            assert validate(f"{i}.1.1.1") == False

[golden jasper]

With dot separation etc.

[steel pollen]

yea my code doesnt take in all numbers from 0-255

[north sphinx]

if validate(f"{i}.1.1.1") == False:
            assert validate(f"{i}.1.1.1") == False

what?

[jagged turtle]

that will check for each number in "2" "5" "5". (using for on a string iters the chars)

[steel pollen]

i want to check between 0-255

so should i use range?

[jagged turtle]

Yeah

[steel pollen]

i havent done it in a while lol

[jagged turtle]

for i in range(1, 256, 1)
1 - Start point (Inclusive)
256 - End point (EXCLUSIVE!)
1 - Step (not really needed since that's default anyway)

[golden jasper]

You would need more than 1 options with or in regex

[keen cedar]

what about {1,3} in regex?

oh wait that wouldn't work, nm

[jagged turtle]

Number of last token to match XD

[steel pollen]

re.fullmatch(r'^((25[0-5]|(2[0-4]|1\d|[1-9]|)\d)\.?\b){4}$', ip)

its this from online

stack overflow

[jagged turtle]

Yeah thats a method :D

[steel pollen]

lol yea

how to do this?

done this ```py
for i in range(255):
assert validate(f"{i}.1.1.1") == True

[jagged turtle]

Should be for i in range(1, 256, 1) (see my above message for why)

[north sphinx]

and four of them (nested)

[steel pollen]

ohh i missed this

thanks

tests arnt testing lol

[north sphinx]

for i in range(1, 256):
  for j in range(1, 256):
    for k in range(1, 256):
      for l in range(1, 256):
        assert validate(f"{i}.{j}.{k}.{l}") == True

[steel pollen]

im just checking for first byte

[north sphinx]

you want to vary each byte from 1-255

[steel pollen]

saves time

[jagged turtle]

Oh god the inefficiency

[north sphinx]

well the test wants you to check all 4 bytes

[steel pollen]

test_numb3rs.py catches numb3rs.py only checking if first byte of IPv4 address is in range
    expected exit code 1, not 0```

[steel pollen]

it says first byte here

[jagged turtle]

I assume you're doing this for like learning and stuff

[steel pollen]

yea

its an online course

[jagged turtle]

Just checking since the ipaddress module does exist-

[steel pollen]

im on week 7/9

[north sphinx]

I'm confused now, I think it wants all 4 bytes to be checked? but yeah the wording isn't really indicative of one way or the other

[steel pollen]

yea and im not accounting for leading 0s

[steel pollen]

ill try ur method

[jagged turtle]

That has to loop 4.2 billion ips.

Its slow.

[north sphinx]

yeh it would be

[jagged turtle]

Vector math would like to speak with you

or yknow...

[steel pollen]

lets stick to the topic

both methods dont work for my checks

[north sphinx]

okay anywhere where the rules are clearly laid out?

[steel pollen]

yea

https://cs50.harvard.edu/python/psets/7/numb3rs/

check this

[jagged turtle]

We just got XY problemed.

See Here

[steel pollen]

what does that mean?

[jagged turtle]

The XY problem is You came up with a solution (Y) for problem X, but it wasnt working so you asked how to fix solution Y

byte_data = ip.split()

for byte in byte_data:
    if 0<int(byte)<256:
         ... # Other logic

You check 4 times and its a guaranteed validity.

[steel pollen]

oh yea

this is smart

[north sphinx]

*split(".")

[jagged turtle]

Good catch

Im too used to my custom string methods

They auto grab the sep

[steel pollen]

yep thanks

[north sphinx]

probably add a try/except for the non-numerical invalid test cases

!d str.isdecimal or this

[proper quartz]

str.isdecimal

str.isdecimal()```
Return `True` if all characters in the string are decimal characters and there is at least one character, `False` otherwise. Decimal characters are those that can be used to form numbers in base 10, e.g. U+0660, ARABIC-INDIC DIGIT ZERO. Formally a decimal character is a character in the Unicode General Category “Nd”.

[north sphinx]

but that might trip you up because it includes 0-9 from other scripts

so try/except it is

[jagged turtle]

Wayyy too used to seeing .isdigit()

[steel pollen]

im doing this in pytest btw

how abouts to do it

i need to hardcode a value

[jagged turtle]

Damn

[north sphinx]

!d str.isdigit

[proper quartz]

str.isdigit

str.isdigit()```
Return `True` if all characters in the string are digits and there is at least one character, `False` otherwise. Digits include decimal characters and digits that need special handling, such as the compatibility superscript digits. This covers digits which cannot be used to form numbers in base 10, like the Kharosthi numbers. Formally, a digit is a character that has the property value Numeric\_Type=Digit or Numeric\_Type=Decimal.

[jagged turtle]

Im stupid

Good to know that that's somehow worse XDDD

[north sphinx]

I don't rmb if this one has this quirk or not, but it seems to have other quirks so

[jagged turtle]

Also nice to see someone taking the free CS50

-# Ive been contemplating

[steel pollen]

yea its good intro

i need to do more projects after i finish tho

[jagged turtle]

Fair fair, if you need inspo, dm me, I always have reasonable ish project ideas

[steel pollen]

i want to work in finance do u have any inspo?

i dont have access to a terminal like bloomberg tho

i wish i did 😦

[jagged turtle]

XD Fair

Uhhh finance projects...

Denominations counters
Conversion Calculators
Stock readers (if you cover that sector)

[steel pollen]

conversion calcs?

ive done a bitcoin indexer using an api

[jagged turtle]

Like GBP to USD or USD to AUD, fetching the latest data ofc

[steel pollen]

oh ok

nice

ill try

[jagged turtle]

Also ive personally never used pytest, I usually define my own testing methods

[steel pollen]

its part of cs50

im still failing the tests

[jagged turtle]

Then again im insane apparently as far as devs go XD

Hmm the module does explicitly say about regex...

[steel pollen]

true

maybe i should implement a regex that checks the first byte

using group(1)

[jagged turtle]

Im experimenting with the builtin re module instead of the installable one

[steel pollen]

ok i didnt install anything either

[jagged turtle]

Do you have access to the tests they use for PyTest?

[steel pollen]

no i have to make it robust myself

which is annoying

[jagged turtle]

Sigh, if you had access to the tests 😭

[steel pollen]

ikr

should i just submit

its just one check

im pretty sure i dont need to get all ticks for the cert

[jagged turtle]

Thats how prod apis die

[steel pollen]

wdym

[jagged turtle]

"Its just one check"

[steel pollen]

loll

[jagged turtle]

Ive seen too many apps die from just one check

I think I have a hit

[steel pollen]

what is it

[jagged turtle]

Im just running a full Ip range test

[steel pollen]

ok lmk how it is

[jagged turtle]

Could be a while, im remoted onto my dev laptop

[steel pollen]

ill come back in 10 mins lol

[ashen creek]

|

[steel pollen]

?

[jagged turtle]

Ok just dropped python all my threads and 24 worker processes

Still going to take a bit, but nowhere near as long

Golden.

ip_expr = re.compile(
    r"\b("
    r"(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])"
    r"\."
    r"(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])"
    r"\."
    r"(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])"
    r"\."
    r"(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])"
    r")\b"
)

This is the regex im using

[steel pollen]

cant u use {4}

instead of repeating the line 4 times

[jagged turtle]

Could allow for an ending .

Besides the fact that windows is screaming for resources right now, its working

[steel pollen]

man

this is so inefficent

[jagged turtle]

Im afraid IPs are kinda like that

Thats why we have the ipaddress module

[steel pollen]

shouldnt we just check for the first byte

like it says in the test check

although urs is correct in the long run

[north sphinx]

it's saying your test only checks for the first byte

[jagged turtle]

Well no because what if its:
"192.269.0.15"

[twilit drum]

Are you testing... every IP address? Isn't that a little ridiculous?

[jagged turtle]

Oh mines regex testing :D

we make sure it workin

[north sphinx]

I do think this is the way to go though, but regex works sooo

[steel pollen]

in my check for 1 byte

i dont want to test for all ips tbh

too long

[north sphinx]

honestly I'm confused on what the failing test is expecting

[north sphinx]

P.S you could do this

ip_expr = re.compile(
    r"\b("
    r"\.".join([r"(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])"] * 4)
    r")\b"
)

[jagged turtle]

Eh true, .join is a thing

removes readability a lil but :P

Also me literally done.

[north sphinx]

anything outside sys/re is disallowed

so, 🤷

[jagged turtle]

Damn no builtin ipaddress i guess

[steel pollen]

idk

so what now?

[jagged turtle]

Say screw it and utilise split. See what you can roll around with that

[steel pollen]

i need to hardcode values tho

[jagged turtle]

ips = [
    "127.0.0.1",
    "255.255.255.255",
    "512.512.512.512",
    "1.2.3.1000",
    "192.168.001.1",
    "cat"
]

Like that you mean?

For loop through the values and work out what checks you need to pass

[steel pollen]

yep like that is good

then i can check if its num,

[jagged turtle]

I will say, I do have a working implementation

[steel pollen]

def test_first():
assert validate("256.1.1.1") == False
assert validate("1.256.1.1") == False
assert validate("1.1.256.1") == False
assert validate("1.1.1.256") == False

[proper quartz]

Hey @steel pollen!

Please edit your message to use a code block

```py
print('Hello, world!')
```

This will result in the following:

print('Hello, world!')```

[steel pollen]

i just done this

and it works lol

although could be done better

!close

[proper quartz]

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