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'
-# a=open(r"C:\Users\Hp\Desktop\文档.txt","w",encoding='utf-8')
-# a.write('小兰：12本\n')
-# a.close()
-# with open(r"C:\Users\Hp\Desktop\文档.txt","a",encoding='utf-8')as a:  #a
-#     a.write("123\n")
-# e=""
-# with open(r"C:\Users\Hp\Desktop\文档.txt","r",encoding='utf-8')as a:  #a
-#     for w in a:  #遍历整个文档a
-#         if "123" in w:  #判断123是不是在w里面
-#             w=w.replace("123","456")
-#         e+=w
-# with open(r"C:\Users\Hp\Desktop\文档.txt","w",encoding='utf-8')as a:
-#     a.write(e)
-with open(r"C:\Users\Hp\Desktop\文档.txt","w",encoding='utf-8')as a:
-    a.write("45646")
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+# 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'
+# a=open(r'C:\Users\Public\Desktop\14.txt','w',encoding='utf-8')
+# a.write("以德服人")  #写入
+# a.close() #关闭
+# with open(r'C:\Users\Public\Desktop\14.txt','w',encoding='utf-8') as a: #a是变量名
+#     a.write("哈哈哈哈\n") 
+    #可以省略关闭文件close()
+with open(r'C:\Users\Public\Desktop\14.txt','a',encoding='utf-8') as a: #a是变量名
+    a.write("下我的教案忘记了大\n") 
+    #可以省略关闭文件close()
+# with open(r'C:\Users\Public\Desktop\14.txt','r',encoding='utf-8') as a: #a是变量名
+#     a=a.read()
+#     print(a)
+# with open(r'C:\Users\Public\Desktop\14.txt','r',encoding='utf-8') as a: #a是变量名
+#     for i in a: #遍历出所有的内容
+#         if '嘿嘿' in i:    #用if判断查找的东西是否在文档里面
+#             print('在里面')
+e=""
+with open(r'C:\Users\Public\Desktop\14.txt','r',encoding='utf-8') as a:  #a
+    for w in a:  #遍历整个文档a
+        if "456" in w:  #判断嘿嘿是不是在w里面
+            w=w.replace("456","779")  #replace(被修改的,想要的)
+        e+=w   #修改完之后不会发生改变因为我们用的是r只读模式所以不会发生改变
+with open(r'C:\Users\Public\Desktop\14.txt','w',encoding='utf-8') as a: 
+    a.write(e)   #在这里我们用w模式添加进入我们上边修改的e
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