Starting point for homework

import sys

filename = sys.argv[1]

source = open(filename, 'r')
longest = -1
for line in source:
    longest = max(longest, len(line))
source.close()
print 'longest line is', longest

source = open(filename, 'r')
shortest = 10000000
for line in source:
    shortest = min(shortest, len(line))
source.close()
print 'shortest line is', shortest

data.txt

Date,Species,Count
2012-05-14,coyote,5
2012-05-14,deer,14
2012-05-14,bear,2
2012-05-15,rabbit,26
2012-05-15,bear,1
2012-05-16,magpie,3

functional.py

def add(a, b):
    return a + b

def mul(a, b):
    return a * b

def for_each(func, values):
    assert len(values) > 0, "Must have some data"
    temp = values[0]
    for v in values[1:]:
        temp = func(temp, v)
    return temp

numbers = [7, 1, 4, -5, 3]

print "sum is", for_each(add, numbers)
print "product is", for_each(mul, numbers)
print "greatest is", for_each(max, numbers)
print "least is", for_each(min, numbers)
print "but what about", for_each(max, [])