python读取大文件

with open('xxx.sql', 'r', encoding = 'utf-8') as f:
    with open('article.sql', 'w+', encoding='utf8') as fw:
        for line in f:
            a = line.replace('``','`article_slww`')
            n +=1
            # print(a)
            dosomething(a)
            fw.write(a)