Question 7 Use a dictionary to count the frequency of letters in the input string. Only letters should be counted, not blank spaces, numbers, or punctuation. Upper case should be considered the same as lower case. For example, count_letters("This is a sentence.") should return {'t': 2, 'h': 1, 'i': 2, 's': 3, 'a': 1, 'e': 3, 'n': 2, 'c': 1}.

Strings_Lists_Dictionaries_7.py

def count_letters(text):
  result = {}
  text = text.lower()
  # Go through each letter in the text
  for letter in text:
    # Check if the letter needs to be counted or not
    if letter .isalpha() and letter not in result:
        result[letter] = text.lower().count(letter)
    # Add or increment the value in the dictionary
  return result

print(count_letters("AaBbCc"))
# Should be {'a': 2, 'b': 2, 'c': 2}

print(count_letters("Math is fun! 2+2=4"))
# Should be {'m': 1, 'a': 1, 't': 1, 'h': 1, 'i': 1, 's': 1, 'f': 1, 'u': 1, 'n': 1}

print(count_letters("This is a sentence."))
# Should be {'t': 2, 'h': 1, 'i': 2, 's': 3, 'a': 1, 'e': 3, 'n': 2, 'c': 1}

To ensure we get the letters in lowercase:
I have updated the above solution.

def count_letters(text):
  result = {}
  # Go through each letter in the text
  for letter in text:
    # Check if the letter needs to be counted or not
    if letter .isalpha() and letter not in result:
    # Add or increment the value in the dictionary
      result[letter.lower()]=text.lower().count(letter)
  return result

print(count_letters("AaBbCc"))
# Should be {'a': 2, 'b': 2, 'c': 2}

print(count_letters("Math is fun! 2+2=4"))
# Should be {'m': 1, 'a': 1, 't': 1, 'h': 1, 'i': 1, 's': 1, 'f': 1, 'u': 1, 'n': 1}

print(count_letters("This is a sentence."))
# Should be {'t': 2, 'h': 1, 'i': 2, 's': 3, 'a': 1, 'e': 3, 'n': 2, 'c': 1}

def count_letters(text):
result = {}
text = text.lower()

Go through each letter in the text

for letter in text:
# Check if the letter needs to be counted or not
if letter.isalpha() :
# Add or increment the value in the dictionary
count = text.count(letter)
result[letter] = count
return result

def count_letters(text):
result = {}
text = text.lower()

for letter in text:

checking if letter is within a-z

if letter.isalpha():
    if letter not in result:
        result[letter] = 0
    result[letter] += 1

return result

print(count_letters("AaBbCc"))
{'a': 2, 'b': 2, 'c': 2}

print(count_letters("Math is fun! 2+2=4"))
{'m': 1, 'a': 1, 't': 1, 'h': 1, 'i': 1, 's': 1, 'f': 1, 'u': 1, 'n': 1}

print(count_letters("This is a sentence."))
{'t': 2, 'h': 1, 'i': 2, 's': 3, 'a': 1, 'e': 3, 'n': 2, 'c': 1}

def count_letters(text):
result = {}
text = text.lower()
for letter in text:
if letter not in result and letter.isalpha():
result[letter] = text.count(letter)
return result

I keep getting the white spaces what did I do wrong?

def count_letters(text):
result = {}
text=text.lower()

Go through each letter in the text

for letter in text:
# Check if the letter needs to be counted or not
if letter.isalpha() and letter not in result:
result[letter]=0
result[letter]=text.count(letter)

# Add or increment the value in the dictionary
___

return result

print(count_letters("AaBbCc"))

Should be {'a': 2, 'b': 2, 'c': 2}

print(count_letters("Math is fun! 2+2=4"))

Should be {'m': 1, 'a': 1, 't': 1, 'h': 1, 'i': 1, 's': 1, 'f': 1, 'u': 1, 'n': 1}

print(count_letters("This is a sentence."))

Should be {'t': 2, 'h': 1, 'i': 2, 's': 3, 'a': 1, 'e': 3, 'n': 2, 'c': 1}

def count_letters(text):
result = {}
text = text.lower()

Go through each letter in the text

for letter in text:
    if letter in result:
        result[letter] += 1
    else:
        result[letter] = 1
# Check if the letter needs to be counted or not
# Add or increment the value in the dictionary
        
return result

print(count_letters("AaBbCc"))

Should be {'a': 2, 'b': 2, 'c': 2}

print(count_letters("Math is fun! 2+2=4"))

Should be {'m': 1, 'a': 1, 't': 1, 'h': 1, 'i': 1, 's': 1, 'f': 1, 'u': 1, 'n': 1}

print(count_letters("This is a sentence."))

Should be {'t': 2, 'h': 1, 'i': 2, 's': 3, 'a': 1, 'e': 3, 'n': 2, 'c': 1}