gdhenry92-优快云博客

原创 [laravel]上传下载文件实例

// 上传实例Route::post('file/upload', function (\Illuminate\Http\Request $request) { // 判断请求中是否有文件photo和上传过程是否出错 if($request->hasFile('photo') && $request->file('photo')->isValid...

2019-12-25 11:16:02 367

原创 [PHP]切换国内composer源

使用阿里云 Composer 全量镜像composer config -g repo.packagist composer https://mirrors.aliyun.com/composer/

2019-12-20 14:56:25 517

原创 [php]单例模式

单例模式(构造方法私有化)class A { private $name; private function __construct($name) { $this->name = $name; } public static function getObject($name) { return new self($n...

2019-12-19 09:46:09 122

原创 [MySQL]练习题4

Which countries have a GDP greater than every country in Europe? [Give the name only.] (Some countries may have NULL gdp values)select name from worldwhere gdp > all(select gdp from world where c...

2019-12-13 17:01:06 722

原创已读书籍

1. <<利用python进行数据分析第二版>>线上阅读(比书上翻译要好)：https://www.jianshu.com/p/72b6c83bb69e2. SQL必知必会(第四版)3. 如何用数据解决实际问题...

2019-12-13 12:32:30 115

原创 [MySQL]练习题3

select * from nobelwhere winner='EUGENE O\'Neill'SELECT winner, subject FROM nobel WHERE yr=1984 ORDER BY subject IN ('Physics','Chemistry') ,subject,winner

2019-12-12 16:39:23 119

原创 [MySQL]练习题2

美國、印度和中國(USA, India, China)是人口又大，同時面積又大的國家。排除這些國家。顯示以人口或面積為大國的國家，但不能同時兩者。顯示國家名稱，人口和面積SELECT name,population,area FROM world WHERE (area>3000000 AND population<250000000) OR (area<3000000 AN...

2019-12-11 18:01:57 1227

原创 [MySQL]练习题1

11.顯示所有國家名字,其首都和國家名字是相同的SELECT name FROM world WHERE name = capital12.顯示所有國家名字,其首都是國家名字加上”City”SELECT name FROM world WHERE capital = concat(name, ' City')13.找出所有首都和其國家名字,而首都要有國家名字中出現SELECT ca...

2019-12-11 16:00:54 382 1

原创【MySQL】按各科成绩进行排序，并显示排名

按各科成绩进行排序，并显示排名select s_id,a.c_id,c_name,s_score,rank from (select s_id,c_id,s_score,case when c_id = @cid then if(@prevRank = s_score,@curRank,@curRank := @curRank + 1) else @curRank := 1...

2019-11-12 16:03:51 5167

原创【python】加权中位数计算

1.安装模块pip install wquantiles2.数据准备state = ["阿拉巴马州","阿拉斯加州","亚利桑那州","阿肯色州","加利福尼亚州","科罗拉多州","康涅狄格州","特拉华州"]population = [4779736,710231,6392017,2915918,37253956,5029196,3574097,897934]murder = [5...

2019-11-07 11:09:07 2078 1

原创【matplotlib】windows系统解决jupyter notebook中文显示问题

1.导入模块，查看matplotlib配置所在的路径import matplotlibmatplotlib.matplotlib_fname()2.下载字体，放到字体文件夹的ttf下字体URL：https://www.fontpalace.com/font-download/SimHei/3.修改配置文件matplotlibrc修改如下4.删除缓存目录C:\用户\你的用...

2019-11-06 10:51:34 2507 2

原创【pandas】读写数据库

安装相关模块pip install mysql-connectorpip install pymysqlpip install sqlalchemy1.导入相关模块import pymysqlfrom sqlalchemy import create_engineimport pandas as pdpymysql.install_as_MySQLdb()2.读数据库con...

2019-11-05 14:28:47 163

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