Count Letter Occurrences | Dataford Interview Questions

Cognizant text-processing utilities may need to count how often a particular character appears in an input string. Given a string and a target letter, return the number of exact occurrences of that letter.

The comparison is case-sensitive. Count only characters equal to the target letter, and do not count different uppercase or lowercase versions. The target is guaranteed to contain exactly one character. The input string may contain letters, digits, spaces, and punctuation.

Formal Specification

Implement count_letter(text, letter).

Input: text, a string, and letter, a string containing exactly one character.
Output: An integer representing the number of positions in text whose character equals letter.
The input string is not modified.

Constraints

0 <= len(text) <= 100,000
letter contains exactly one character
Matching is case-sensitive
text may contain spaces, digits, punctuation, and alphabetic characters

Function Signature

def count_letter(text, letter):

Your question is Count Letter Occurrences. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem