Вот несколько методов, которые можно использовать для подсчета количества строк в текстовом файле в Python:

Метод 1: использование цикла

def count_lines(filename):
    count = 0
    with open(filename, 'r') as file:
        for line in file:
            count += 1
    return count
filename = 'your_file.txt'
line_count = count_lines(filename)
print("Number of lines:", line_count)

Метод 2: использование метода readlines()

def count_lines(filename):
    with open(filename, 'r') as file:
        lines = file.readlines()
    return len(lines)
filename = 'your_file.txt'
line_count = count_lines(filename)
print("Number of lines:", line_count)

Метод 3: использование sum()и выражения-генератора

def count_lines(filename):
    with open(filename, 'r') as file:
        line_count = sum(1 for line in file)
    return line_count
filename = 'your_file.txt'
line_count = count_lines(filename)
print("Number of lines:", line_count)

Метод 4. Использование метода splitlines()

def count_lines(filename):
    with open(filename, 'r') as file:
        content = file.read()
    lines = content.splitlines()
    return len(lines)
filename = 'your_file.txt'
line_count = count_lines(filename)
print("Number of lines:", line_count)