Parsing text file in python

Since this seems to come from ping command, you could use grep like this :

grep -oP 'ttl=\d+\s+time=\K[\d\.]+' file    

Output :

17.2
12.6
11.7

Note :

It's very simple to search SO or/and google to use this regex in pure python.

Hint :

Support of \K in regex

Bonus

Because I still have to play with python :

(in a bash shell) :

python2 <<< $'import re\nf = open("/tmp/file", "r")\nfor textline in f.readlines():\n\tmatches = re.finditer("ttl=\d+\s+time=([\d\.]+)ms", textline)\n\tresults = [float(match.group(1).strip()) for match in matches if len(match.group(1).strip())]\n\tif results:\n\t\tprint results[0]\nf.close()\n'

Since you asked for Python, here it is:

$ ping -c 4 8.8.8.8 | python -c 'import sys;[ sys.stdout.write(l.split("=")[-1]+"\n") for l in sys.stdin if "time=" in l]'            
10.5 ms

9.22 ms

9.37 ms

9.71 ms

Note, this has stdout buffering, so you may want to add sys.stdout.flush() . Feel free to convert this from one liner to a script

You specified that your data is already in a text file. So asuming that your text file is called data.txt

#we will be using the regular expression library for this example
import re 

#open the "data.txt" (named data_file in a scope)
with open("data.txt") as data_file: 
    #read the text from the data_file into ping_data
    ping_data = data_file.read() 
    found_data = re.findall('time=(.*)ms', ping_data)

with open('found.txt', 'w') as found_file:
    for pattern in found_data:
        found_file.write(pattern+"\n")

This fill output a file called found.txt with the following:

17.2
12.6
11.7

In the example we just open your data.txt file. Then read the data form it. Then find all the occurrences of the regular expression pattern that will return the data you are looking for.

time=(.*)ms means *a string of any size between the letters time= and ms

Then after we have found the patern we simply write it to another file called found.txt, writing one line at a time until its complete.