Introduction to Python

def is_data(line):

    """ Returns true if the line has data

    and false otherwise (header, comments, etc)"""

    if line.startswith('#'):

        # skip comments

        return False

    elif line.startswith('D'):

        # skip title row

        return False

    else:

        return True

# script starts here...

source = open('data.txt', 'r')

number = 0

# count number of data records

for line in source:

    if is_data(line) == True:

        number = number + 1

source.close()

print "Total number of data records:", number