Finds all products of the digits of 5-digit numbers and creates two files: one contains the products and keys, ranked by products, while the other contains the number of occurrences of each product, ranked by occurrence, both in ascending order.

products.py

# Written by Assil Ksiksi
# Date: Thursday, December 29th, 3:12 am (GMT +4)

# I basically wrote this to determine whether or not a pattern exists in the products of the digits
# of all 5-digit numbers. Sadly, none exist, or at least I didn't see one.

# Runtime is fairly slow. It takes 1.05916786194s for all 5-digit numbers. I don't see how it
# can be optimized, so that should do the trick.

# References:
# http://coreygoldberg.blogspot.com/2008/07/python-counting-items-in-list.html
# http://drumcoder.co.uk/blog/2010/sep/11/find-key-value-python-dictionary/
# http://www.saltycrane.com/blog/2007/09/how-to-sort-python-dictionary-by-keys/

results = []
occurences = {}

for i in xrange(10000, 100000):
    product = 1
    if '0' not in str(i):
        for j in [int(x) for x in str(i)]:
            product *= j
        results.append(product)

for i in set(results):
    occurences[i] = results.count(i)

# Creates a file in script directory
f = open('keys.txt', 'w')

# Prints in order of magnitude of products by iterating through a sorted list of (key, value) pairs - the keys are also reversed (greatest to least)
for key, value in sorted(occurences.iteritems(), reverse=True):
    f.write("Product: {0}, Occurences: {1}\n".format(key, value)) # Writes lines to file instead of terminal/command prompt

# Closes file
f.close()

g = open('values.txt', 'w')

# Prints in order of occurences by iterating through a list of sorted (key, value) pairs and using a lambda function to switch their places, making them (value, key). They are reversed as well.
for key, value in sorted(occurences.iteritems(), key=lambda (k, v): (v,k), reverse=True):
    g.write("Product: {0}, Occurences: {1}\n".format(key, value))
    
g.close()