python 文件处理 li = [[']] for i in li: print(','.join(i)) # join字符串拼接 语文,数学,英语 100,122,123 从原文件末尾开始写入 # 方法一 with open('user_info.txt','r+',encoding='utf-8') as f: f.read() f.write('a1') # 方法二 with open('user_info.txt','r+',encoding='utf-8') as f: f.seek…