find the number of occurrence of letter in a txt file using python

Question

I need to read the letter from a .txt file and print the number of occurrence in txt file. so far i have been able to print the content in one line but having issue with the cou

Answer 1

Here you go. Hopefully your professor will ask you to explain your work.

grades = open('grades.txt').read().split()
for grade in sorted(set(grades),
                    key=lambda x: ord(x[0])*3-('+'in x)+('-'in x)):
    print ('{} students got {}'.format(grades.count(grade), grade))

Answer 2

You can use collections.Counter for this

with open('grades.txt') as f:
    print(Counter(f.read()))

Example

this is a test that has letters

Output

Counter({'t': 7,
         ' ': 6,
         's': 5,
         'a': 3,
         'h': 3,
         'e': 3,
         'i': 2,
         'l': 1,
         'r': 1})

Or to only include letters

from string import ascii_letters
with open('grades.txt') as f:
    print(Counter(i for i in f.read() if i in ascii_letters))

Edit
Without the use of any other libraries, the manual way to do the same thing as above:

from string import ascii_letters
d = {}
with open('grades.txt') as f:
    for letter in d.read():
        if letter in ascii_letters:
            if letter in d:
                d[letter] += 1
            else:
                d[letter] = 1

If your file looks something like

A A+ B B- B B+ B+ A A- B+

Then the modification to the above code would be

d = {}
with open('grades.txt') as f:
    for grade in d.read().split():
        if grade in d:
            d[grade] += 1
        else:
            d[grade] = 1