save project

diy.py

@@ -5,8 +5,11 @@ with open(r'C:\Users\win 10\Desktop\po.txt','w',encoding='utf-8') as po:
     po.write('李明：15\n')
 with open(r'C:\Users\win 10\Desktop\po.txt','a',encoding='utf-8') as po:
     po.write('小兰:12\n')
+new=''
 with open(r'C:\Users\win 10\Desktop\po.txt','r',encoding='utf-8') as po:
-    for data in po:
-        if '小兰:12' in data:
-            print('zai')
-            
\ No newline at end of file
+    for d in po:
+        if '小兰:12' in d:
+            d=d.replace('小兰:12','小兰:15')
+        new+=d
+with open(r'C:\Users\win 10\Desktop\po.txt','w',encoding='utf-8') as po:
+    po.write(new)