Character frequency dictionary using count() function

Question

I need help with a function that will take a string and return a dictionary with how many times each letter is in the string using the count() function

For example, for "0010101", it returns a dictionary saying:

The character frequency of "0010101" is {'0': 4, '1': 3}

def character_frequency(string):
  if len(string) == 0:
   return "{}"
# insert loop to determine the character counts in the string here

#test code for reference 
tests = ["", "0010101", "aaabbb"]

for x in tests:
  print('The character frequency of "' + x + '" is', character_frequency(x))

It's a sad day when [`collections.Counter`](https://docs.python.org/3/library/collections.html#collections.Counter) exists, but one isn't allowed to use it. — 9769953, May 02 '21 at 12:20
yea, sadly can't import anything from the collections module :( — saturns, May 02 '21 at 12:21
I'm afraid you'll need to take a few steps back though, and go through some old stuff. For example, you return `"{}"`, which is a string (containing an opening and closing brace); not a dict as you probably intent to. — 9769953, May 02 '21 at 12:22
yea, I'll work on that. Right now my concern is figuring out the main part of the assignment which is returning the dictionary with the character frequencies — saturns, May 02 '21 at 12:29
Use the `count` function, or `count` *method*? I assume the latter, since I wouldn't know of a standard `count` function. — 9769953, May 02 '21 at 12:38

Marcin-99 · Accepted Answer · 2021-05-02T12:37:58.440

0

If you need to use count() function:

def character_frequency(string):
    return {char: string.count(char) for char in set(string)}

edited May 02 '21 at 12:37

answered May 02 '21 at 12:29

Marcin-99

41
2

`count` and `set` work directly on a string. No need to convert things into a list first. – 9769953 May 02 '21 at 12:35

toolic · Answer 2 · 2021-05-02T12:38:56.457

If you are open to a different implementation than count, one way is to use get with a default of 0:

def character_frequency(string):
    freq = {}
    for c in string:
        freq[c] = freq.get(c, 0) + 1
    return freq

#test code for reference 
tests = ["", "0010101", "aaabbb"]

for x in tests:
    print('The character frequency of "' + x + '" is', character_frequency(x))

Output:

The character frequency of "" is {}
The character frequency of "0010101" is {'0': 4, '1': 3}
The character frequency of "aaabbb" is {'a': 3, 'b': 3}

Marcel.af · Answer 3 · 2021-05-02T12:53:44.363

0

txt = "I love apples, apple are my favorite fruit"
print(dict(zip(txt,[txt.count(char) for char in txt])))

Count the occurrences of each character in the string and store them as list

Merge the above list with the corresponding characters and convert to dictionary

edited May 02 '21 at 12:53

answered May 02 '21 at 12:45

Marcel.af

73
9

Character frequency dictionary using count() function

3 Answers3