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

Question

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!

Answer 1

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()