auto save

diy.py

-with open(r"c:\Users\admin\Desktop\test.txt","w",encoding="uft-8")as file
+with open(r"c:\Users\admin\Desktop\test.txt","w",encoding="utf-8") as file:
     file.write("小王：12本\n小江：20本\n")
-with open(r"c:\Users\admin\Desktop\test.txt","a",encoding="uft-8")as file
+with open(r"c:\Users\admin\Desktop\test.txt","a",encoding="utf-8") as file:
     file.write("小明：12本\n")
-with open(r"c:\Users\admin\Desktop\test.txt","r",encoding="uft-8")as file
-    a=qwe.read()
-    print(a)
-with open(r"c:\Users\admin\Desktop\test.txt","r",encoding="uft-8")as file
+with open(r"c:\Users\admin\Desktop\test.txt","r",encoding="utf-8") as file:
+    a=file.read()
+with open(r"c:\Users\admin\Desktop\test.txt","r",encoding="utf-8") as file:
+    new_data=""
     for data in file:
-        if"小江,20本"in data:
-            print("找到了")
+        if "小王:12本" in data:
+            data=data.replace("小王:12本","小王:50本")
+        new_data=new_data+data
+    print(new_data)    
\ No newline at end of file