python counting letters in string without count function

Question

I am trying to write a program to count the occurrences of a specific letter in a string without the count function. I made the string into a list and set a loop to count but th

Answer 1

Although someone else has solved your problem, the simplest solution to do what you want to do is to use the Counter data type:

>>> from collections import Counter
>>> letter = 'a'
>>> myString = 'aardvark'
>>> counts = Counter(myString)
>>> print(counts)
Counter({'a': 3, 'r': 2, 'v': 1, 'k': 1, 'd': 1})
>>> count = counts[letter]
>>> print(count)
3

Or, more succinctly (if you don't want to check multiple letters):

>>> from collections import Counter
>>> letter = 'a'
>>> myString = 'aardvark'
>>> count = Counter(myString)[letter]
>>> print(count)
3

The simplest way to do your implementation would be:

count = sum(i == letter for i in myString)

or:

count = sum(1 for i in myString if i == letter)

This works because strings can be iterated just like lists, and False is counted as a 0 and True is counted as a 1 for arithmetic.