[SOLVED] python print string match from file but only second column

keif · 09-08-2016, 12:39 PM

Hello all,

I'm writing a python script that searches standard parameter info from a config file so that it can find unique info to the right of the parameter. For instance here is my list:

Code:

SID 2861
RID 383
hostname server1
hostaddress server1.domain.com
ifcfg-eth0 192.168.2.100
eth0-netmask 255.255.255.0
gateway 192.168.2.1
ifcfg-eth1 192.168.1.100
eth1-netmask 255.255.255.0
lanes 6 1 2 3 4 5 31
xterminal no
macs yes

The first column is always the same per server and the second column changes.

I have found a way to match the line and print the info on the second column:

Code:

for line in open("ss2861.cfg"):
	if "SID" in line:
		SID = line[4:8]
		print SID

But this is a bad solution, because a lot of the parameters in the second column vary in length so it's not a good solution to just count how many characters are after the first parameter.

I've been trying to find a way to search the first parameter AND print the second column. So far I've only been able to find one or the other.

This split works, but now I have the whole second columns without having searched for the specific parameter:

Code:

with open('ss2861.cfg') as inf:
	for line in inf:
		parts = line.split()
		if len(parts) > 1:
			print parts[1]

I'm new to python and I know bash would be able to handle this with awk, but I'm trying to force myself to do this with python so I can learn another scripting tool.

If anyone can assist I'd be very grateful. If this is not enough info then please let me know. Thank you! Keith

grail · 09-08-2016, 01:08 PM

Before assisting further, I would like to know what should be printed for the following line which clearly contains more than 2 fields:

Code:

lanes 6 1 2 3 4 5 31

I am assuming for the line to be unique for a server then any one of those numbers could change and not just the second column 6??

keif · 09-08-2016, 02:10 PM

Quote:

Originally Posted by grail

Before assisting further, I would like to know what should be printed for the following line which clearly contains more than 2 fields:

Code:

lanes 6 1 2 3 4 5 31

I am assuming for the line to be unique for a server then any one of those numbers could change and not just the second column 6??

Yes, that is correct.

In the 'lanes' line, the second column is the total number of lanes (6) and the numbers following that are the sequence (1 through 5 and 31). Sometimes it's 6 lanes but a different sequence like 2 through 7 and other varieties. Also there can be more than just 6 lanes at any given server set up.

I should have pointed that out. My plan when writing this threat was to learn the two-column method first and then take that information to push further into the more complicated areas (Such as the 'lanes' line).

Thanks for looking at this, please let me know if I can provide any more info to make things easier. Keith

keif · 09-08-2016, 03:27 PM

Quote:

Originally Posted by grail

Before assisting further, I would like to know what should be printed for the following line which clearly contains more than 2 fields:

Code:

lanes 6 1 2 3 4 5 31

I am assuming for the line to be unique for a server then any one of those numbers could change and not just the second column 6??

Hello grail,

I finally found a solution to this:

Code:

for line in open("ss2861.cfg"):
	if "SID" in line:
		print line.split("SID ",1)[1]

Thanks for your assistance. If you have a more elegant way of doing this then please share. I can use the info. Keith

grail · 09-08-2016, 09:19 PM

I probably would have the separator as a space, that way you get access to both the first and second items should they be needed. For your future idea of the 'lanes' if you use space you will then have
access to all columns in future indexes of the list created, once you remove the max_split number.

keif · 09-09-2016, 09:48 AM

Quote:

Originally Posted by grail

I probably would have the separator as a space, that way you get access to both the first and second items should they be needed. For your future idea of the 'lanes' if you use space you will then have
access to all columns in future indexes of the list created, once you remove the max_split number.

This seems to do the trick better than what I previously posted:

Code:

for line in open("ss2861.cfg"):
	if "SID" in line:
		SID = line.split()[1]
                print SID

This might be the key to moving forward towards the next step. I'll be working on that today. Thanks again

HMW · 09-12-2016, 02:57 AM

Quote:

Originally Posted by keif

This seems to do the trick better than what I previously posted:

Code:

for line in open("ss2861.cfg"):
	if "SID" in line:
		SID = line.split()[1]
                print SID

This might be the key to moving forward towards the next step. I'll be working on that today. Thanks again

I think Python is a great language, but for this case I find it to be somewhat overkill. You can do this with a fairly simple sed:

Code:

sed -n 's/SID \([0-9].*$\)/\1/p' config.txt 
2861

Best regards,
HMW