#This program counts the number of times that
#letters appear in a text document and sorts them
#by frequncy.

#Used to keep a matching between letters and
#the number of times they have been seen.
aDict  = { }

filename = "msnd.txt"

f = open(filename, "r")

#count of the total number of letters
count = 0


letter = f.read(1)


while len( letter) > 0 :
    count = count + 1

    letter = letter.lower()

    #Find out how many times have I seen this letter
    #and add one to the count, and then
    #update the dictionary
    aDict[letter] = aDict.get(letter, 0) + 1


    letter = f.read(1)

f.close()

print("all done!")

aList = []


#Get the letters and the counts out of the
#dictionary,
for key in aDict:
  value = aDict[key]
  aTuple = (value, key)
  aList.append(aTuple)

#and sort them by frequency.
aList.sort(reverse=True)

#Make a nice printed output
for item in aList:
  letter = item[1]
  numTimes = item[0]
  #print(letter)
  print("{:.4f} - {}".format( numTimes/count, letter) )