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'
-file1=open(r'E:\test.txt','w',encoding='utf-8')
-file1.write('小兰：12本')
-file1.write('小丽：11本')
-file1.write('李文：9本')
-file1.write('张伟：16本')
-file1.close()
\ No newline at end of file
+new_data=''
+with open(r'E:\test.txt','r',encoding='utf-8') as file1:
+    for data in file1:
+        if '小强：12本' in data:
+            data=data.replace('小强：12本','小强：11本')
+        if '小兰：12本' in data:    
+            data=data.replace('小兰：12本','小兰：14本')
+        new_data+=data
+with open(r'E:\test.txt','w',encoding='utf-8') as file1:
+    file1.write(new_data)
+with open(r'E:\test.txt','r',encoding='utf-8') as file1:
+    a=file1.read()
+    print(a)
\ No newline at end of file