Question regarding lists and regex
Here is a simple program, which queries /var/log/daemon on my OpenBSD box and
gets the list of valid ntp peers.
Questions:
what is the easiest way for me to create lists on the fly, by that I mean like
perl
push my @foo, something_from_say_stderr. The reason is as you can ip = [""]
statement before the for loop, I want to avoid that and use list within the
second ip loop, where I extract the ip address. Am I confusing?
regex: I presume this is rather a dumb question, anyways here it comes! as you
can see from my program, pattIp = r\d{1,3}\ etc, is there any other easy
way
to group the reptitions, instead of typing the same regex 4 times.
TIA
Prabhu
-
amazon: [~/working/programs/python/regex]
ttyp4: [109]$ cat syslog.py
#!/usr/bin/env python
# $Id: syslog.py,v 1.6 2006/11/09 06:24:03 pgurumur Exp $
import getopt, re, os, string, sys, time
(dirname, program) = os.path.split(sys.argv[0])
argc = len(sys.argv)
def usage():
print program + ": options"
print "options: "
print " --filename | -f [ name of the file ]"
print " --help | -h [ prints this help ]"
sys.exit(1)
if __name__ == "__main__":
if (argc <= 1):
usage()
else:
try:
opts, args = getopt.getopt(sys.argv[1:], "f:h", ["help", "filename="])
except getopt.GetoptError:
usage()
else:
filename = ""
for optind, optarg in opts:
if optind in ("-f", "--filename"):
filename = optarg
elif optind in ("-h", "--help"):
usage()
if len(filename):
fh = 0
try:
fh = open(filename, "r")
except IOError, (error, message):
print program + ": cannot open " + filename + ": " + message
sys.exit(1)
pattNtp = r'.*ntpd(?=.*now\s+valid)'
count = 0
ip = [""]
pid = 0
for line in fh.readlines():
if re.match(pattNtp, line.strip(), re.IGNORECASE):
string = line.strip()
pattPid = r'\[\d{1,5}\]'
pidMatch = re.search(pattPid, string, re.IGNORECASE)
if pidMatch is not None:
pid = int(re.sub(r'\[|\]', "", pidMatch.group()))
pattIp = r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}'
match = re.search(pattIp, string, re.IGNORECASE)
if match is not None:
ip.append(match.group())
count += 1
print "NTP program started with pid:", pid
print "Number of valid peers:", count
for x in ip:
if len(x):
print x
fh.close()
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Question on regex
Hello all -
I have a file which has IP address and subnet number and I use regex to extract
the IP separately from subnet.
pattern used for IP: \d{1,3}(\.\d{1,3}){3}
pattern used for subnet:((\d{1,3})|(\d{1,3}(\.\d{1,3}){1,3}))/(\d{1,2})
so I have list of ip/subnets strewn around like this
10.200.0.34
10.200.4.5
10.178.9.45
10.200/22
10.178/16
10.100.4.64/26,
10.150.100.0/28
10/8
with that above examples:
ip regex pattern works for all IP address
subnet regex pattern works for all subnets
problem now is ip pattern also matches the last 2 subnet numbers, because it
falls under ip regex.
to fix this problem, i used negative lookahead with ip pattern:
so the ip pattern now changes to:
\d{1,3}(\.\d{1,3}){3}(?!/\d+)
now the problem is 10.150.100.0 works fine, 10.100.4.64 subnet gets matched
with ip pattern with the following result:
10.100.4.6
Is there a workaround for this or what should change in ip regex pattern.
python script:
#!/usr/bin/env python
import re, sys
fh = 0
try:
fh = open(sys.argv[1], "r")
except IOError, message:
print "cannot open file: %s" %message
else:
for lines in fh.readlines():
lines = lines.strip()
pattIp = re.compile("(\d{1,3}(\.\d{1,3}){3})(?!/\d+)")
pattNet = re.compile("((\d{1,3})|(\d{1,3}(\.\d{1,3}){1,3}))/(\d{1,2})")
match = pattIp.search(lines)
if match is not None:
print "ipmatch: %s" %match.groups()[0]
match = pattNet.search(lines)
if match is not None:
print "subnet: %s" %match.groups()[0]
fh.close()
output with that above ip/subnet in a file
ipmatch: 10.200.0.34
ipmatch: 10.200.4.5
ipmatch: 10.178.9.45
subnet: 10.200
subnet: 10.178
ipmatch: 10.100.4.6
subnet: 10.100.4.64
subnet: 10.150.100.0
subnet: 10
TIA
Prabhu
begin:vcard
fn:Prabhu Gurumurthy
n:Gurumurthy;Prabhu
org:Silver Spring Networks;IT
adr:Suite 205;;2755 Campus Drive;San Mateo;CA;94403;USA
email;internet:[EMAIL PROTECTED]
title:Network Engineer
tel;work:(650) 357 8770 x134
tel;home:(650) 585 6527
tel;cell:(831) 224 0894
x-mozilla-html:FALSE
url:http://www.silverspringnet.com
version:2.1
end:vcard
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help parsing ipv6 addresses and subnets
Hello list,
I would like to parse IPv6 addresses and subnet using re module in
python. I am able to either parse the ipv6 address or ipv6 network but
not both using single line. any help appreciated. BTW is there a
metacharacter for hex digits.
Thanks
Prabhu
-
-
#!/usr/bin/env python2.5
# $Id: $
import re, os, Queue, sys
from optparse import OptionParser
# for debug purposes only
import pdb
argc = len(sys.argv)
(dirname, program) = os.path.split(sys.argv[0])
def error(Message):
if Message:
global program
print "%s: %s" %(program, Message)
sys.exit(1)
def cisco_parse(FileName):
if FileName:
fh = None
if os.path.exists(FileName):
try:
fh = open(FileName, "r")
except IOError, message:
error(message)
else:
count = 0
flag = True
while flag:
try:
lines = fh.next()
except StopIteration:
flag = False
else:
line = lines.strip()
rehex = "[A-Fa-f0-9]"
# to parse ipv6 address
format = \
"((%s{1,4}:?:){1,7}%s{1,4})" %(rehex, rehex)
# to parse ipv6 subnet
# format = \
# "((%s{1,4}:?:){1,7}%s{1,4}(?=(::/\d{1,3})))"
%(rehex, rehex)
reip6 = re.compile(format)
match = reip6.search(line)
if match is not None:
tupleLen = len(match.groups())
if tupleLen == 2:
print count, match.groups()[0]
elif tupleLen == 3:
print count, match.groups()[0] + match.groups()[2]
count += 1
fh.close()
fh = None
def ParseCmdLine():
parser = OptionParser(usage="%prog [options]", version="%prog 1.0")
parser.add_option("-f", "--filename",
help="cisco config to read", dest="file")
(options, args) = parser.parse_args()
fileName = None
if options.file:
fileName = options.file
if fileName:
cisco_parse(fileName)
if __name__ == "__main__":
if argc <= 1:
error("too few arguments, use -h or --help to view all options")
else:
ParseCmdLine()
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help with pyparsing
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
All,
I have the following lines that I would like to parse in python using
pyparsing, but have some problems forming the grammar.
Line in file:
table const { 207.135.103.128/26, 207.135.112.64/29 }
table persist { ! 10.200.2/24, 10.200/22 }
table const { 192.168/16, ! 172.24.1/29, 172.16/12, 169.254/16 }
table persist { 10.202/22 }
table const { 10.206/22 }
table const { \
10.205.1/24, \
169.136.241.68, \
169.136.241.70, \
169.136.241.71, \
169.136.241.72, \
169.136.241.75, \
169.136.241.76, \
169.136.241.77, \
169.136.241.78, \
169.136.241.79, \
169.136.241.81, \
169.136.241.82, \
169.136.241.85 }
I have the following grammar defn.
tableName = Word(alphanums + "-" + "_")
leftClose = Suppress("<")
rightClose = Suppress(">")
key = Suppress("table")
tableType = Regex("persist|const")
ip4Address = OneOrMore(Word(nums + "."))
ip4Network = Group(ip4Address + Optional(Word("/") +
OneOrMore(Word(nums
temp = ZeroOrMore("\\" + "\n")
tableList = OneOrMore(Optional("\\") |
ip4Network | ip4Address | Suppress(",") | Literal("!"))
leftParen = Suppress("{")
rightParen = Suppress("}")
table = key + leftClose + tableName + rightClose + tableType + \
leftParen + tableList + rightParen
I cannot seem to match sixth line in the file above, i.e table name with
KS, how do I form the grammar for it, BTW, I still cannot seem to ignore
comments using table.ignore(Literal("#") + restOfLine), I get a parse error.
Any help appreciated.
Thanks
Prabhu
- -
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Re: help with pyparsing
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Paul McGuire wrote:
> On Dec 9, 11:01 pm, Prabhu Gurumurthy <[EMAIL PROTECTED]> wrote:
>> -BEGIN PGP SIGNED MESSAGE-
>> Hash: SHA1
>>
>> All,
>>
>> I have the following lines that I would like to parse in python using
>> pyparsing, but have some problems forming the grammar.
>>
>> Line in file:
>> table const { 207.135.103.128/26, 207.135.112.64/29 }
>> table persist { ! 10.200.2/24, 10.200/22 }
>> table const { 192.168/16, ! 172.24.1/29, 172.16/12, 169.254/16 }
>> table persist { 10.202/22 }
>> table const { 10.206/22 }
>> table const { \
>>10.205.1/24, \
>>169.136.241.68, \
>>169.136.241.70, \
>>169.136.241.71, \
>>169.136.241.72, \
>>169.136.241.75, \
>>169.136.241.76, \
>>169.136.241.77, \
>>169.136.241.78, \
>>169.136.241.79, \
>>169.136.241.81, \
>>169.136.241.82, \
>>169.136.241.85 }
>>
>> I have the following grammar defn.
>>
>> tableName = Word(alphanums + "-" + "_")
>> leftClose = Suppress("<")
>> rightClose = Suppress(">")
>> key = Suppress("table")
>> tableType = Regex("persist|const")
>> ip4Address = OneOrMore(Word(nums + "."))
>> ip4Network = Group(ip4Address + Optional(Word("/") +
>> OneOrMore(Word(nums
>> temp = ZeroOrMore("\\" + "\n")
>> tableList = OneOrMore(Optional("\\") |
>>ip4Network | ip4Address | Suppress(",") | Literal("!"))
>> leftParen = Suppress("{")
>> rightParen = Suppress("}")
>>
>> table = key + leftClose + tableName + rightClose + tableType + \
>> leftParen + tableList + rightParen
>>
>> I cannot seem to match sixth line in the file above, i.e table name with
>> KS, how do I form the grammar for it, BTW, I still cannot seem to ignore
>> comments using table.ignore(Literal("#") + restOfLine), I get a parse error.
>>
>> Any help appreciated.
>> Thanks
>> Prabhu
>
> Prabhu -
>
> This is a good start, but here are some suggestions:
>
> 1. ip4Address = OneOrMore(Word(nums + "."))
>
> Word(nums+".") will read any contiguous set of characters in the
> string nums+".", so OneOrMore is not necessary for reading in an
> ip4Address. Just use:
>
> ip4Address = Word(nums + ".")
>
>
> 2. ip4Network = Group(ip4Address + Optional(Word("/") +
> OneOrMore(Word(nums
>
> Same comment, OneOrMore is not needed for the added value to the
> ip4Address:
>
> ip4Network = Group(ip4Address + Optional(Word("/") + Word(nums
>
>
> 3. tableList = OneOrMore(Optional("\\") |
>ip4Network | ip4Address | Suppress(",") |
> Literal("!"))
>
> The list of ip4Networks is just a comma-delimited list, with some
> entries preceded with a '!' character. It is simpler to use
> pyparsing's built-in helper, delimitedList, as in:
>
> tableList = Group( delimitedList(Group("!"+ip4Network)|ip4Network) )
>
>
> Yes, I know, you are saying, "but what about all those backslashes?"
> The backslashes look like they are just there as line continuations.
> We can define an ignore expression, so that the table expression, and
> all of its contained expressions, will ignore '\' characters as line
> continuations:
>
> table.ignore( Literal("\\") + LineEnd() )
>
> And I'm not sure why you had trouble with ignoring '#' + restOfLine,
> it works fine in the program below.
>
> If you make these changes, your program will look something like this:
>
> tableName = Word(alphanums + "-" + "_")
> leftClose = Suppress("<")
> rightClose = Suppress(">")
> key = Suppress("table")
> tableType = Regex("persist|const")
> ip4Address = Word(nums + ".")
> ip4Network = Group(ip4Address + Optional(Word("/") + Word(nums)))
> tableList = Group(delimitedList(Group("!"+ip4Network)|ip4Network))
> leftParen = Suppress("{")
> rightParen = Suppress("}")
>
> table = key + leftClose + tableName + rightClose + tableType + \
> leftParen + tableList + rightParen
> table.ignore(Literal("\\") + LineEnd())
> table.ignore(Literal("#") + restOfLine)
>
> #
