将字符串拆分成单独的单词，忽略其他所有内容

import re

def split_string_to_words(string):
    # 去除标点符号和特殊字符，只保留字母和数字
    string = re.sub(r'[^\w\s]', '', string)
    
    # 按空格分割字符串，得到单词列表
    words = string.split()
    
    # 去除空字符串和无意义的单词
    words = [word for word in words if word.strip() and word.lower() not in ['a', 'an', 'the']]
    
    # 转换为小写字母
    words = [word.lower() for word in words]
    
    # 去除重复单词
    words = list(set(words))
    
    return words

# 示例用法
string = "Hello, this is a sample string. It contains multiple words."
words = split_string_to_words(string)
print(words)