regular expressions and matches
Hello,
I have recently written a small function that will verify that an IP
address is valid.
==SNIP==
import re
ipAddress = raw_input('IP Address : ')
def validateIP(ipAddress):
ipRegex =
r^([01]?\d\d?|2[0-4]\d|25[0-5])\.([01]?\d\d?|2[0-4]\d|25[0-5])\.([01]?\d\d?|2[0-4]\d|25[0-5])\.([01]?\d\d?|2[0-4]\d|25[0-5])$
re_ip = re.compile(ipRegex)
match = re_ip.match(ipAddress)
if not match:
print an error has occured with ipAddress
return match
else:
return match
print(validateIP(ipAddress))
==SNIP==
I was having issues trying to get my code working so that I could pass
the IP addresses and it would return a true or false. When it matches I
get something that looks like this.
python ip_valid.py
IP Address : 192.158.1.1
_sre.SRE_Match object at 0xb7de8c80
As I am still attempting to learn python I am interested to know how I
could get the above to return a true or false if it matches or does not
match the IP address. I would also like to expand that so that if the
IP is wrong it requests the IP address again and recalls the function.
I have done the same thing in php very easily but python appears to be
getting the better of me. Any assistance and advice would be greatly
appreciated.
Regards,
Johhny
--
http://mail.python.org/mailman/listinfo/python-list
Re: regular expressions and matches
Johhny wrote: I was having issues trying to get my code working so that I could pass the IP addresses and it would return a true or false. When it matches I get something that looks like this. python ip_valid.py IP Address : 192.158.1.1 _sre.SRE_Match object at 0xb7de8c80 As I am still attempting to learn python I am interested to know how I could get the above to return a true or false if it matches or does not match the IP address. you can use the return value right away. the match function/method returns None if it fails to find a match, and None is treated as a false value in a boolean context: http://docs.python.org/ref/Booleans.html if you get a match instead, you get a match object (SRE_Match), which is treated as True. if you really really really want to return True or False, you can do result = bool(re.match(...)) /F -- http://mail.python.org/mailman/listinfo/python-list
Re: regular expressions and matches
Johhny wrote:
Hello,
I have recently written a small function that will verify that an IP
address is valid.
(snip re.match() based solution - just one remark: compiling the regexp
on each function call is more than useless)
I was having issues trying to get my code working so that I could pass
the IP addresses and it would return a true or false. When it matches I
get something that looks like this.
python ip_valid.py
IP Address : 192.158.1.1
_sre.SRE_Match object at 0xb7de8c80
As I am still attempting to learn python I am interested to know how I
could get the above to return a true or false if it matches or does not
match the IP address.
If you re-read the fine manual, you'll notice that re.match() returns
either None or a Match object. Since, in a boolean context, None evals
to False and a Match object to True, just convert the return of re.match
to a boolean:
return bool(re_ip.match(ipAddress))
BTW, don't mix outputs and a logic. Your validateIp() function should
*only* validate, not print anything (except for debugging purpose, but
then it should either go to a log or at least to stderr, stdout is for
normal program outputs).
I would also like to expand that so that if the
IP is wrong it requests the IP address again and recalls the function.
Then wrap the raw_input()/validateIp() into a loop. And wrap this loop
into a function !-)
def get_valid_ip(prompt=please enter an ip,
errormsg=Sorry, %s is not a valid ip):
while True:
ip = raw_input(%s : % prompt).strip()
if validateIp(ip):
return ip
else:
print errormsg % ip
ip = get_valid_ip()
I have done the same thing in php very easily but python appears to be
getting the better of me.
Knowledge doesn't map one-to-one from one language to another.
--
bruno desthuilliers
python -c print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in '[EMAIL PROTECTED]'.split('@')])
--
http://mail.python.org/mailman/listinfo/python-list
Re: regular expressions and matches
Johhny wrote:
Hello,
I have recently written a small function that will verify that an IP
address is valid.
==SNIP==
import re
ipAddress = raw_input('IP Address : ')
def validateIP(ipAddress):
ipRegex =
r^([01]?\d\d?|2[0-4]\d|25[0-5])\.([01]?\d\d?|2[0-4]\d|25[0-5])\.([01]?\d\d?|2[0-4]\d|25[0-5])\.([01]?\d\d?|2[0-4]\d|25[0-5])$
Good lord! You might as well be writing in assembly! The re module
docs should include a customer warning label.
Regular expressions are not the answer here. Probably 80% of the regex
virus could be stamped out if people used split instead. How about
something simpler, like this:
def ipValid(ipAddress):
dots = ipAddress.split(.)
if len(dots) != 4:
return False
for item in dots:
if not 0 = int(item) = 255:
return False
return True
...although even this function (like yours) will declare as valid an
IP address like 0.255.0.0.
For a real-world application, how about:
import socket
try:
mm = socket.inet_aton(ipAddress)
return True # We got through that call without an error, so it is
valid
except socket.error:
return False # There was an error, so it is invalid
re_ip = re.compile(ipRegex)
match = re_ip.match(ipAddress)
if not match:
print an error has occured with ipAddress
return match
else:
return match
print(validateIP(ipAddress))
==SNIP==
I was having issues trying to get my code working so that I could pass
the IP addresses and it would return a true or false. When it matches I
get something that looks like this.
python ip_valid.py
IP Address : 192.158.1.1
_sre.SRE_Match object at 0xb7de8c80
As I am still attempting to learn python I am interested to know how I
could get the above to return a true or false if it matches or does not
match the IP address. I would also like to expand that so that if the
IP is wrong it requests the IP address again and recalls the function.
I have done the same thing in php very easily but python appears to be
getting the better of me. Any assistance and advice would be greatly
appreciated.
Regards,
Johhny
--
http://mail.python.org/mailman/listinfo/python-list
