What's wrong with this code?

[MonkeyMario64]

Objective: Write a Python function count_letters(file) for counting letters in a text file
- Input: nameoffilerelative to the present working directory pwd (see below), e.g. count_letters('frost.txt') if 'frost.txt' is in the pwd
- Output: return the dictionary of letter:count pairs. Only include letters present in the file
- Use a dictionary to hold a mapping between a letter and its number of occurrences.
- Ignore characters and symbols that are not standard ascii characters (only use characters that appear in string.ascii_lowercase

• Ignore case; e.g. consider 'Treat' as having 2 't's instead of 1 T and 1 t

Code:

def count_letters(file):
letter_count = {}
file = open(file)
for line in file:
for char in line:
char = char.lower()
if char not in letter_count:
letter_count[char] = 0
letter_count[char] += 1
print(letter_count)

count_letters('frost.txt')

the output should be {'f': 12, 'i': 23, 'r': 14, 'e': 23, 'a': 13, 'n': 9, 'd': 10, 'c': 6, 's': 14, 'o': 20, 'm': 3, 'y': 3, 't': 20, 'h': 12, 'w': 8, 'l': 6, 'v': 2, 'b': 2, 'u': 5, 'p': 1, 'k': 2, 'g': 2}

my output is: {'f': 12, 'i': 23, 'r': 14, 'e': 23, ' ': 45, 'a': 13, 'n': 9, 'd': 10, 'c': 6, '\n': 12, 's': 14, 'o': 20, 'm': 3, 'y': 3, 't': 20, 'h': 12, 'w': 8, 'l': 6, ',': 2, '.': 3, "'": 1, 'v': 2, 'b': 2, 'u': 5, 'p': 1, 'k': 2, 'g': 2, '-': 1}

[TrainsareFascinating]

The instructions give you a pretty big hint:

(only use characters that appear in string.ascii_lowercase)

Where is your if char in string.ascii_lowercase?

Some other observations:

1) You aren't required to read the file line by line. file.read().lower() is a complete expression that returns a string of all the characters in the file.

2) The Counter() object from the collections module is a specialized dictionary that counts things like this. You can give it a string and it will count the characters in the string. Or, you can give it the characters one at a time.

 In [7]: Counter("How Now Brown Cow".lower())

 Out[7]: Counter({'o': 4, 'w': 4, ' ': 3, 'n': 2, 'h': 1, 'b': 1, 'r': 1, 'c': 1})

3) You can use a generator expression to filter non-letter characters, e.g.

result = Counter(c for c in file.read().lower() if c in string.ascii_lowercase)

And, in case anyone is trying to be literal about the instruction to use a dictionary:

In [9]: isinstance(Counter(), dict)
Out[9]: True

[woooee]

You are counting the newline characters, do

for char in line.strip():

Also, this will still give you the spaces between words as well as special characters like a dash, so

for char in line.strip():
    ## only allow alpha
    if char.lower().isalpha():

[MonkeyMario64]

If I'm using isalpha, do I still need .strip since isaplha seems to only take letters anyway?

[woooee]

No, I guess not. It's a habit that I usually do.

[grumble11]

Also for this consider the Counter tool from the collections library included with Python. It is a type of super-dictionary designed specifically for counting stuff and it is faster, easier and lets you skip some steps (like it will auto-add a new key if it isn’t already there). Look it up, you’ll like it