auto save

diy.py

+# 写入数据
+# with open(r'C:\Users\EDY\Desktop\test.txt','w',encoding="utf-8") as file:
+#     file.write("小兰：12本\n")
+#     file.write("小强：10本\n")
+#     file.write("李明：15本\n")
+
+# 读取并修改数据 小强11本
+new_data = ''
+with open(r'C:\Users\EDY\Desktop\test.txt','r',encoding="utf-8") as file:
+    for data in file:    # 遍历文件
+        if "10本" in data:   # 判断10本在不在
+            data = data.replace("10","11")   # 替换数据
+        new_data += data
+
+# 重新写入
+with open(r'C:\Users\EDY\Desktop\test.txt','w',encoding="utf-8") as file:
+    file.write(new_data)    
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