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'
-with open(r"C:\Users\22\Desktop\test.txt",'a',encoding='utf-8') as file1:
-    file1.write('ikun：20本\n')
\ No newline at end of file
+new_data = ''
+with open(r"C:\Users\22\Desktop\test.txt",'r',encoding='utf-8') as file1:
+    for data in file1:
+        if '小丽：11本' in data:
+            data=data.replace('小丽：11本','小丽：16本')
+        new_data+=data
+
+with open(r"C:\Users\22\Desktop\test.txt",'w',encoding='utf-8') as file1:
+    file1.write(new_data)