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'
 
-# 创建文件
-# file1 = open(r"C:\Users\Administrator\Desktop\test.txt"
-#         ,'a',encoding='utf-8')
+# #创建文件
+# file1 = open(r"C:\Users\Administrator\Desktop\test.txt",'a',encoding='utf-8')
 # # 写入数据
 # file1.write('小兰：12本\n')
 # file1.write('小强：10本\n')
 # file1.write('李明：15本\n')
 # # 关闭文件
 # file1.close()
+# with open(r"C:\Users\Administrator\Desktop\test.txt",'w',encoding='utf-8') as file1:
+#     file1.write('小兰：12本\n')
+#     file1.write('李文：9本\n')
+#     file1.write('张伟：16本\n')
 
-with open(r"C:\Users\Administrator\Desktop\test.txt",'a',encoding='utf-8') as file1:
-    file1.write('小兰：12本\n')
-    file1.write('李文：9本\n')
-    file1.write('张伟：16本\n')
-    
+with open(r"C:\Users\Administrator\Desktop\test.txt",'r',encoding='utf-8')as file:
+    new_data = ''
+    for data in file:
+        if "李文：9本" in data:
+            data = data.replace('李文：9本','李文：10本')
+        new_data += data
+        # new_data = new_data + data
+with open(r"C:\Users\Administrator\Desktop\test.txt",'w',encoding='utf-8')as file:
+    file.write(new_data)
+
+with open(r"C:\Users\Administrator\Desktop\test.txt",'r',encoding='utf-8')as file:
+    data = file.read()
+    print(data)