Code that gives a sorted file list

sort_filepath_alphabetically.py

files = [f for f in os.listdir(gpx_folderpath) if os.path.isfile(os.path.join(gpx_folderpath, f))]

def sort_key(file):
    num = re.search(r'(\d+)', file).group(1)
    num = num.replace('-', ' ')
    num = int(num) if num.isdigit() else 0
    return (num, file)

files.sort(key=sort_key)

With tthe line files.sort(key=sort_key)

['1.gpx',
 '2.gpx',
 '3.gpx',
 '4.gpx',
 '5.gpx',
 '6.gpx',
 '7.gpx',
 '8-9.gpx',
 '10.gpx',           <---
 '11.gpx']           <---

Without tthe line files.sort(key=sort_key)

['1.gpx',
 '10.gpx',         <---
 '11.gpx',         <---
 '2.gpx',
 '3.gpx',
 '4.gpx',
 '5.gpx',
 '6.gpx',
 '7.gpx',
 '8-9.gpx']