Подсчет вхождений символа в строку

Вот несколько методов подсчета количества вхождений символа в строку:

Метод 1: использование цикла

def count_occurrences(string, character):
    count = 0
    for char in string:
        if char == character:
            count += 1
    return count
# Example usage
string = "Hello, World!"
character = "l"
occurrences = count_occurrences(string, character)
print(occurrences)  # Output: 3

Метод 2: использование метода count()

string = "Hello, World!"
character = "l"
occurrences = string.count(character)
print(occurrences)  # Output: 3

Метод 3. Использование списка

string = "Hello, World!"
character = "l"
occurrences = len([char for char in string if char == character])
print(occurrences)  # Output: 3

Метод 4. Использование регулярных выражений

import re
string = "Hello, World!"
character = "l"
occurrences = len(re.findall(character, string))
print(occurrences)  # Output: 3

Метод 5. Использование модуля collections

from collections import Counter
string = "Hello, World!"
character = "l"
occurrences = Counter(string)[character]
print(occurrences)  # Output: 3