import sys, os

print ""
print "Running Script..."
print ""
print "This program analyzes word frequency in a file and"
print "prints a report on the n most frequent words."
print ""

filename = raw_input("File to analyze? ")
if os.path.isfile(filename):
  print "The file", filename, "exists!"
else:
  print "The file", filename, "doesn't exist!"
  sys.exit()
  print ""
output = raw_input("Output analysis of how many words? ")

readfile = open(filename, 'r+')

words = readfile.read().split()
wordcount = {}
for word in words:
  if word in wordcount:
    wordcount[word] += 1
  else:
    wordcount[word] = 1

sortbyfreq = sorted(wordcount,key=wordcount.get,reverse=True)
for word in sortbyfreq:
  print "%-20s %10d" % (word, wordcount[word])

limit = {enter number}
counter = 0
for word in sortbyfreq:
  print "%-20s %10d" % (word, wordcount[word])
  counter += 1
  if counter >= limit:
    break

from collections import Counter
sortbyfreq = Counter(words)  # Instead of the wordcount dictionary + for loop.

n = int(raw_input('How many?: '))
for item, count in sortbyfreq.most_common(n):
    print "%-20s %10d" % (item, count)