Question

I have 2 csv files

One has traceroutes to different IP addresses(The last entry here is the target IP) also (their are variable number of entries in every row as different routes need different no. of hops)

other has a list of targets and their real world positional coordinates

some targets in first file dont have an entry in the 2nd and vice versa

How do I get the real world cordinates into the 1st csv file with matching target IPs?
the 2 files are like these

hop1,hop2,hop3,hop4,target1
hop1,hop2,hop3,hop4,hop5,hop6,target2

target99,position    

Answer 1

import csv

ip_file = open("ipfile.csv")
position_file = open("positionfile.csv")
output = open("output.csv", "wt")

ips = {}    

# create a CSV reader for the proper csv file with locations:
reader = csv.reader(position_file)
for line in reader:
    ips[line[0]] = line[1]


#now you have the IP + location association

for line in ip_file.readlines():
    ip = line.split(",")[-1].strip()
    output.write(line.strip() + ", " + (ips[ip] if ip in ips else "location unknown") + "\n" )

output.close()