auto save

diy.py

 # 写入同学们的捐赠明细：'小兰：12本'、'小丽：11本'、'李文：9本'、'张伟：16本'
-file=open(r"C:\Users\Administrator\Desktop\book.txt","w",encoding='utf-8')
-file.write('小兰：12本\n小丽：11本\n李文：9本\n张伟：16本')
-file.close()
\ No newline at end of file
+# file=open(r"C:\Users\Administrator\Desktop\book.txt","w",encoding='utf-8')
+# file.write('小兰：12本\n小丽：11本\n李文：9本\n张伟：16本\n')
+# file.close()
+
+# with open(r"C:\Users\Administrator\Desktop\book.txt","a",encoding='utf-8') as file:
+#     file.write("牛魔王：99本")
+new_data=""
+with open(r"C:\Users\Administrator\Desktop\book.txt","r",encoding='utf-8') as file:
+    for i in file:
+        if "张伟：16本" in i:
+            i=i.replace("张伟：16本","张伟：99本")
+        new_data=new_data+i
+with open(r"C:\Users\Administrator\Desktop\book.txt","w",encoding='utf-8') as file:
+    file.write(new_data)
\ No newline at end of file