Why does as.factor return a character when used inside apply?

I want to convert variables into factors using apply(): a <- data.frame(x1 = rnorm(100), x2 = sample(c(\"a\",\"b\"), 100, replace = T),

tcl98x9c是硬屏还是软屏？tcl98x9c画质体验怎么样？

The resource could not be resolved (VS 2010 RC)

I\'ve got WPF 4 app that has a number of UserControls that share styles in their child controls. So I\'m creating a number of styles in my App.xaml as . For example:

how to migrate DB from MySql to MS-SQL?

i want to migrate my whole DB from MySQL to MS-Sql server. though i am open to use any tool,am restricted to use only free avil开发者_如何学运维able tools.Use Microsoft SQL Server Migration Assistan (

JavaScript development - bookmarking lines of code?

I constantly find m开发者_StackOverflow社区yself rewriting the same lines of code in the Firebug console to test my application. The application uses UI so much that I don\'t think unit tests are the

索尼笔记本如何调节屏幕亮度？

小天天的丫丫 2022-05-07 11:33 开发者_如何学Python索尼笔记本调节屏幕亮度的方法如下：（1）第一种方法：一般情况下左手按下Fn键（控制功能键），右手用上，下方向键调节亮度，(有的笔记本是F5, F6或者F9, F1

C++ metaprogramming with templates versus inlining

Is it worth to write code like the following to copy array elements: #include <iostream> using namespace std;

Android -- Simple path, use of arcTo causes "UnsupportedOperationException?"

I\'m trying to create a simple path in the onDraw method of a SurfaceView object I\'ve created and the layout editor keeps giving me \"UnsupportedOperationException: null\" whenever I add an arcTo com

Hashing SMTP and NNTP messages?

I want to store and index all of my historical e-mail and news as individual message files, using some computed hash code based on the message body+headers.Then I\'ll index on other things as well --

How to run ant from an Eclipse plugin, send output to an Eclipse console, and capture the build result (success/failure)?

From within an Eclipse plugin, I\'d like to run an Ant build script.I also want to display the Ant output to the user, by displaying it in an Eclipse console.Finally, I also want to wait for the Ant b