auto save

diy.py

 with open('C:\\Users\\Administrator\\ocuments\\lesson13-1\\sales_list.txt',(r),encoding='utf-8')as file:
     # 读取数据
-    a = file.read()
-    # 字符串切片，查看数据类型
-    print(type(a[3:5]))
\ No newline at end of file
+    a = file.readlines()
+    for i in a:
+        print(a)