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Get type of all variables
In R, I'd like to retrieve a list of global variables at the end of my script and iterate over them. Here is my code
6 Answ...
if…else within JSP or JSTL
I want to output some HTML code based on some condition in a JSP file.
13 Answers
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CFLAGS vs CPPFLAGS
I understand that CFLAGS (or CXXFLAGS for C++) are for the compiler, whereas CPPFLAGS is used by the preprocessor.
4 Answer...
How to create directories recursively in ruby?
I want to store a file as /a/b/c/d.txt, but I do not know if any of these directories exist and need to recursively create them if necessary.
How can one do this in ruby?
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How are GCC and g++ bootstrapped?
This has been bugging me for a while. How do GCC and g++ compile themselves?
1 Answer
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Select multiple columns in data.table by their numeric indices
How can we select multiple columns using a vector of their numeric indices (position) in data.table ?
5 Answers
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Makefile经典教程（入门必备） - C/C++ - 清泛网 - 专注C/C++及内核技术
Makefile经典教程（入门必备）Linux_Shell_Classic_tutorialmakefile很重要 什么是makefile？或许很多Winodws的程序员都不知道这个东西，因为那些Windows的IDE都为你做了这个工作，但我觉得要作
makefile。makefile带来的好处就是——“自动化...
Makefile经典教程（入门必备） - C/C++ - 清泛网 - 专注C/C++及内核技术
Makefile经典教程（入门必备）Linux_Shell_Classic_tutorialmakefile很重要 什么是makefile？或许很多Winodws的程序员都不知道这个东西，因为那些Windows的IDE都为你做了这个工作，但我觉得要作
makefile。makefile带来的好处就是——“自动化...
C++对象布局及多态探索之菱形结构虚继承 - C/C++ - 清泛网 - 专注C/C++及内核技术
C++对象布局及多态探索之菱形结构虚继承这次我们看看菱形结构的虚继承。虚继承的引入本就是为了解决复杂结构的继承体系问题。上一篇我们在讨论虚继承时用的是一个简单的继承结构，...这次我们看看菱形结构的虚继承。虚...
Confusion between factor levels and factor labels
There seems to be a difference between levels and labels of a factor in R.
Up to now, I always thought that levels were the 'real' name of factor levels, and labels were the names used for output (such as tables and plots). Obviously, this is not the case, as the following example shows:
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