<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[meghalka的博客]]></title><description><![CDATA[]]></description><link>https://blog.youkuaiyun.com/meghalka</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; meghalka]]></copyright><item><title><![CDATA[Python在子类中修改父类的类属性（变量）]]></title><link>https://blog.youkuaiyun.com/meghalka/article/details/146028734</link><guid>https://blog.youkuaiyun.com/meghalka/article/details/146028734</guid><author>meghalka</author><pubDate>Tue, 04 Mar 2025 22:26:40 +0800</pubDate><description><![CDATA[在子类中修改父类的类变量值，以及父类的哪些变量会由子类继承。]]></description><category></category></item><item><title><![CDATA[python的文件夹的包的结构]]></title><link>https://blog.youkuaiyun.com/meghalka/article/details/129347725</link><guid>https://blog.youkuaiyun.com/meghalka/article/details/129347725</guid><author>meghalka</author><pubDate>Sun, 05 Mar 2023 17:03:57 +0800</pubDate><description><![CDATA[一个包一个文件夹， __init__.py 及其他py文件的大致结构。]]></description><category></category></item><item><title><![CDATA[列表在遍历的过程中删除了列表里的元素会怎么样]]></title><link>https://blog.youkuaiyun.com/meghalka/article/details/128852160</link><guid>https://blog.youkuaiyun.com/meghalka/article/details/128852160</guid><author>meghalka</author><pubDate>Thu, 02 Feb 2023 16:17:06 +0800</pubDate><description><![CDATA[列表在遍历的过程中删除元素，要注意。]]></description><category></category></item><item><title><![CDATA[PyQt5多线程的输出内容显示到窗口]]></title><link>https://blog.youkuaiyun.com/meghalka/article/details/128117445</link><guid>https://blog.youkuaiyun.com/meghalka/article/details/128117445</guid><author>meghalka</author><pubDate>Wed, 30 Nov 2022 17:05:30 +0800</pubDate><description><![CDATA[当PyQt在代码中执行某些操作时，窗口通信和GUI交互将被阻塞。因此，需要用多线程的方式解决出现的视窗卡住的问题。本文完整代码实现：PyQt5多线程的输出内容显示到窗口。]]></description><category></category></item><item><title><![CDATA[关于 pd.Series 排序后用索引和行号取值要注意的问题]]></title><link>https://blog.youkuaiyun.com/meghalka/article/details/128033976</link><guid>https://blog.youkuaiyun.com/meghalka/article/details/128033976</guid><author>meghalka</author><pubDate>Fri, 25 Nov 2022 11:12:38 +0800</pubDate><description><![CDATA[pd.Series 排序后用索引和行号取值要注意的问题。series[n]容易出现纰漏，若要根据行号来取值的话，最好别吝啬于多敲几个字，都用iloc的方法。]]></description><category></category></item><item><title><![CDATA[用openpyxl将DataFrame保存为excel文件时设置单元格的字体和背景色]]></title><link>https://blog.youkuaiyun.com/meghalka/article/details/125393471</link><guid>https://blog.youkuaiyun.com/meghalka/article/details/125393471</guid><author>meghalka</author><pubDate>Tue, 21 Jun 2022 16:27:08 +0800</pubDate><description><![CDATA[用openpyxl将DataFrame数据保存为excel文件时，直接设置某些单元格的字体或背景色。]]></description><category></category></item><item><title><![CDATA[数据库的数据修改与主键]]></title><link>https://blog.youkuaiyun.com/meghalka/article/details/124937677</link><guid>https://blog.youkuaiyun.com/meghalka/article/details/124937677</guid><author>meghalka</author><pubDate>Tue, 24 May 2022 00:37:45 +0800</pubDate><description><![CDATA[原先在mysql数据库的表里没有设置主键，然后在Navicat窗口里修改数据，把这个amount值改为0，无法成功。有警示信息：



其实Navicat是执行了这条语句：


UPDATE `test22`.`zhishu_dongcai_tmp` SET `amount` = 0 WHERE `ts_code` = '399106' AND `trade_date` = Cast('2021-11-23' AS Binary(10)) AND `open` = 2522.23 AND `close` =]]></description><category></category></item><item><title><![CDATA[string.split()和join()示例]]></title><link>https://blog.youkuaiyun.com/meghalka/article/details/122562321</link><guid>https://blog.youkuaiyun.com/meghalka/article/details/122562321</guid><author>meghalka</author><pubDate>Tue, 18 Jan 2022 16:15:50 +0800</pubDate><description><![CDATA[字符串的分割split()和连接join()使用示例。]]></description><category></category></item><item><title><![CDATA[mysql中用表A的数据更新表B]]></title><link>https://blog.youkuaiyun.com/meghalka/article/details/122478220</link><guid>https://blog.youkuaiyun.com/meghalka/article/details/122478220</guid><author>meghalka</author><pubDate>Thu, 13 Jan 2022 17:40:24 +0800</pubDate><description><![CDATA[此次要实现以下目的：把表A中的数据复制到表B，对于表B已有的数据不进行更新。

基本原理：在 INSERT 语句后面用 ON DUPLICATE KEY UPDATE

1. 设置目标表B的主键或唯一索引，以便于SQL插入数据时判断是否重复。 这里设置的是ts_code\trade_date的联合索引，类型unique。

2.insert into tableb select * from tablea ON DUPLICATE KEY UPDATE trade_date=VALUES(trade_dat]]></description><category></category></item><item><title><![CDATA[DataFrame带索引数据写入mysql]]></title><link>https://blog.youkuaiyun.com/meghalka/article/details/122436535</link><guid>https://blog.youkuaiyun.com/meghalka/article/details/122436535</guid><author>meghalka</author><pubDate>Tue, 11 Jan 2022 17:10:51 +0800</pubDate><description><![CDATA[前期代码：

from sqlalchemy import create_engine

engine_ts = create_engine('mysql://root:666666@127.0.0.1:3306/test22?charset=utf8')

#mysql的用户名root，密码666666，test22是数据库名。

res = df.to_sql(name='stock_date_ori', con=engine_ts, if_exists='append', chunksize=5000]]></description><category></category></item></channel></rss>