把声调替换为数字

def replace_symbol_to_number(pinyin):
    """把声调替换为数字"""
    def _replace(match):
        symbol = match.group(0)  # 带声调的字符
        # 返回使用数字标识声调的字符
        return PHONETIC_SYMBOL_DICT[symbol]

    # 替换拼音中的带声调字符
    return RE_PHONETIC_SYMBOL.sub(_replace, pinyin)