Beginner String formatting question

[JAMoore84 at gmail.com]

I apologize for the lack of details in my last post.  This time
formatting program is a piece of a larger program I am trying to write
to de-clutter GPS transmission.  I have a GPS receiver that transmits
its readings via bluetooth.  I've been able to use pySerial and store
X number of bytes, then write that to a file (the next step will be
finding a way to write the stream to a file directly).  The raw GPS
data is tranmitted in the NMEA format (http://vancouver-webpages.com/
peter/nmeafaq.txt):

$GPRMC,024830,V,,N,,E,,,260108,,,N*58
$GPVTG,,T,,M,,N,,K,N*2C
$GPGGA,024831,LAT_GOES_HERE,N,LONG_GOES_HERE,E,0,00,,,M,,M,,*61
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPGSV,3,1,09,09,,,37,13,,,00,18,,,00,23,,,00*75
$GPGSV,3,2,09,01,,,00,29,,,00,14,,,00,26,,,00*7A
$GPGSV,3,3,09,12,,,00,,,,,,,,,,,,*73
$GPRMC,024831,V,LAT_GOES_HERE,N,LONG_GOES_HERE,E,,,260108,,,N*59
$GPVTG,,T,,M,,N,,K,N*2C

the "$GPGGA" and "$GPRMC" lines are the ones that will give you your
Latitude and Longitude data --or the would if I had a signal.
All the entries are comma delimited, so I used the split(',') function
to parse the appropriate statements.  Here's the code for that:
=============================
input = open('c:\sample_readout.txt','r')   #location of the Raw GPS
data
output = open('c:\GPSout.txt', 'w')

output.write("Timestamp \t Latitude \t Longitude \t Velocity")

s = input.readlines()

for line in s:

  if line.startswith('$GPGGA'):
    InputTuple = line.split(',')

    time = InputTuple[1]
    lat  = InputTuple[2]+' '+InputTuple[3]
    long = InputTuple[4]+' '+InputTuple[5]

    out = '\n '+ time + '\t\t' + lat + '\t\t\t' + long

    output.writelines(out)

  elif line.startswith('$GPRMC'):
    InputTuple = line.split(',')

    time = InputTuple[1]
    lat  = InputTuple[3]+' '+InputTuple[4]
    long = InputTuple[5]+' '+InputTuple[6]

    out = '\n '+ time + '\t\t' + lat + '\t\t\t' + long

    output.writelines(out)

  elif line.startswith('$GPVTG'):  #this will give grounp speed in
knts and [7] gives kmph
    InputTuple = line.split(',')

    out = '\n ' + '\t\t' + InputTuple[5]

    output.writelines(out)

input.close()
output.close()
========================

The time stamp for both the GPRMC and GPGGA lines will be stored in
InputTuple[1].

Right now, this program will read the GPS data file and pull out the
necessary information.  I wanted the Format.py program to function as
a module so that I could call Format.FormatTime(time) to change the
HHMMSS GPS data to HH:MM:SS, for readability.  The next step was to
write a FormatCoord function (within the Format module) to do the same
for lat/long data.

Now that I've explained the structure, the argument of
Format.FormatTime() will be InputTuple[1] (the timestamp).  I want to
be able to call that function in the GPS program to read the contents
of InputTuple[1] and write the HH:MM:SS data to the file.

I've incorporated some of your recommendations into my program already
and it looks much better.  Thanks to everyone for your suggestions.

Jimmy