Serial to file?

mini serial capture in python

import sys, os, serial, threading

def monitor():

    ser = serial.Serial(COMPORT, BAUDRATE, timeout=0)

    while (1):
        line = ser.readline()
        if (line != ""):
            #print line[:-1]         # strip \n
            fields = line[:-1].split('; ');
            // ID = fields[0]
                  // TIME = int(fields[1])
            # print fields
            print "device ID: ", ID
            # write to file
            text_file = open("Pdata.log", "w")
            text_file.write(line)
            text_file.close()

        # do some other things here

    print "Stop Monitoring"


""" -------------------------------------------
MAIN APPLICATION
"""  

print "Start Serial Monitor"
print

COMPORT = 4;
BAUDRATE = 115200

monitor()