从文本文件中删除所有标点符号、空格和其他非字母字符(包括数字

import re

def remove_non_letters(file_path, output_path):
    with open(file_path, 'r', encoding='utf-8') as file:
        content = file.read()
    
    # 使用正则表达式替换所有非字母字符为空字符串
    cleaned_content = re.sub(r'[^a-zA-Z]', '', content)
    
    with open(output_path, 'w', encoding='utf-8') as file:
        file.write(cleaned_content)

# 使用函数
remove_non_letters('input.txt', 'output.txt')

def remove_non_letters_large_file(input_path, output_path):
    with open(input_path, 'r', encoding='utf-8') as infile, open(output_path, 'w', encoding='utf-8') as outfile:
        for line in infile:
            cleaned_line = re.sub(r'[^a-zA-Z]', '', line)
            outfile.write(cleaned_line)