calculate percentage of strings instead of statistics

Question

I would like to calculate the percentage of each letter in my file instead of the number. How can I modify the following code?

stat_file = open(filename, 'w')
one_letter = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
for letter in one_letter:
    stat_file.writelines('%s : %d \n' % (letter, statistics[letter]))

Thanks in advance!

Answer 1

First, the total letter counts can have two meanings:

1. Only the words in one_letter (only 'A-Z' in your question)

one_letter = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
stat = {'A': 5, 
          'B':3, 
          'C':9, 
          'U': 5, 
          'D': 9, 
          'a': 99}

total_count = sum(stat.get(letter, 0) for letter in one_letter) # should be 31

2. All the words in your file (including 'a-z', '0-9', ...)

total_count = sum(stat.values()) # should be 130

After that, you can calculate your percentage by

for letter in one_letter:
    stat_file.writelines("%s: %f%%\n" %(letter, \
        stat.get(letter, 0)/float(total_count)*100))

Be reminded that stat.get(letter, 0) just for the case if not all letters in stat.

You can replaced with stat[letter] if you sure A-Z are in stat.

Answer 2

You need to find the sum of all letters like this:

letter_count=0
for letter in one_letter:
    letter_count= letter_count + statistics[letter]

then to get the percentage you need to change your code like this:

stat_file.writelines('%s : %d %% \n' % (letter, (statistics[letter]/letter_count)*100) if statistics[letter]>0 else 0) 

NOTE: I haven't tested the code (no python on this pc installed), but it should work. EDIT: check if the letter has 0 times occurred.