How to clean up .gpx data before writing to a .csv file in python

I am trying to extract specific data from a .gpx file. The data required is 'trkpt' and 'ele', which is location and elevation data. My code listed below does pretty much what I need it to do, but it looks messy, and I only need the numerical data.

gpx_list = []
gpx = open('G:\\14022705.gpx', 'r')  
for line in gpx:
    info = line.split(',')
    if 'trkpt ' in line:
        gpx_list.append(info)
        print line
    if 'ele' in line:
        gpx_list.append(info)
        print line

gpx_list_out = open('G:\\Position_Data2.csv', 'w')  
for line in gpx_list:
    gpx_list_out.write(line[0])

gpx_list_out.close()

Output Example:

['<trkpt lat="-42.6150634" lon="+147.4397831">']
['<ele>1.431</ele>']

Instead I would like it to look like: -42.6150634, +147.4397831, 1.431 all on one line

Any tips on achieving this would be appreciated. I have tried for hours messing around with adding different bits of code but have failed to achieve desired outcome!

Try to incorporate this into your code. The regular expression extracts all digits in each line

import re

gpx_list = []
gpx = open('G:\\14022705.gpx', 'r')      
gpx_list_out = open('G:\\Position_Data2.csv', 'w') 

for line in gpx:
    if 'trkpt ' in line:
      print re.findall(r"[-+]?\d*\.\d+|\d+",line)
      numerical_value=re.findall(r"[-+]?\d*\.\d+|\d+",line)
      gpx_list_out.write(",".join(numerical_value))

gpx_list_out.close()