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Dynamically select data frame columns using $ and a character value
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185
You can't do that kind of subsetting with $. In the source code (R/src/main/subset.c) it states:...
What is Weak Head Normal Form?
...are often caused by this kind of usage of foldl:
foldl (+) 0 [1, 2, 3, 4, 5, 6]
= foldl (+) (0 + 1) [2, 3, 4, 5, 6]
= foldl (+) ((0 + 1) + 2) [3, 4, 5, 6]
= foldl (+) (((0 + 1) + 2) + 3) [4, 5, 6]
= foldl (+) ((((0 + 1) + 2) + 3) + 4) [5, 6]
= foldl (+) (((((0 + 1) + 2) + 3) + 4) + 5) [6]
= f...
What ports does RabbitMQ use?
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151
PORT 4369: Erlang makes use of a Port Mapper Daemon (epmd) for resolution of node names in a cl...
How do you push a Git tag to a branch using a refspec?
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edited Jul 15 '13 at 19:45
answered Oct 31 '10 at 2:08
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How to convert a boolean array to an int array
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edited Sep 9 '16 at 15:43
the Tin Man
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CMake使用教程 - C/C++ - 清泛网 - 专注C/C++及内核技术
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编译完成后，在build目录生成Tutorial.exe，运行Tutorial.exe 25就可以看到运行结果：
运行make install安装程序：
运行make test进行测试：
通过cmake tutorial学习CMake配置方法
http://www.cmake.org/cmake/help/cmake_tutorial.html
可以在源代...
postgresql return 0 if returned value is null
... AND COALESCE( price, 0 ) > ( SELECT AVG( COALESCE( price, 0 ) )* 0.50
FROM ( SELECT *, cume_dist() OVER ( ORDER BY price DESC )
FROM web_price_scan
WHERE listing_Type='A...
xkcd style graphs in MATLAB
...,3);
plot(x,y2,'w','lineWidth',7);
plot(x,y2,'r','lineWidth',3);
xlim([0.95 10])
ylim([0 5])
set(gca,'fontName','Comic Sans MS','fontSize',18,'lineWidth',3,'box','off')
%# add an annotation
annotation(fh,'textarrow',[0.4 0.55],[0.8 0.65],...
'string',sprintf('text%shere',char(10)),'headStyl...
Reduce, fold or scan (Left/Right)?
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Marc GrueMarc Grue
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