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How do I combine two data-frames based on two columns? [duplicate]
...y implies that merge will merge data frames based on more than one column. From the final example given in the documentation:
x <- data.frame(k1=c(NA,NA,3,4,5), k2=c(1,NA,NA,4,5), data=1:5)
y <- data.frame(k1=c(NA,2,NA,4,5), k2=c(NA,NA,3,4,5), data=1:5)
merge(x, y, by=c("k1","k2")) # NA's mat...
F12 Jump to method -> go back to previous method after making the jump?
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Exported service does not require permission: what does it mean?
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Lost httpd.conf file located apache [closed]
...Apache httpd configuration files on various platforms, since this can vary from release to release and platform to platform. The most common answer, however, is either /etc/apache/conf or /etc/httpd/conf
Generically, you can determine the answer by running the command:
httpd -V
(That's a capi...
What is java pojo class, java bean, normal class? [duplicate]
...firstpostcommenter It might be useful to get a description of what POJO is from the person who coined the term. ("encoding business logic into regular java objects rather than using Entity Beans"). In other words, POJO was a name to given to describe "plain old java objects" in order to contrast Ja...
c++ boost::multi_index composite keys efficiency - C/C++ - 清泛网 - 专注C/C++及内核技术
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From：http://stackoverflow.com/questio ... ite-keys-efficiencyc++ boost multi_index
Autoresizing masks programmatically vs Interface Builder / xib / nib
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Escape text for HTML
... you don't want to reference System.Web, you can use WebUtility.HtmlEncode from System
var encoded = WebUtility.HtmlEncode(unencoded);
This has the same effect as HttpUtility.HtmlEncode and should be preferred over System.Security.SecurityElement.Escape.
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Ninject vs Unity for DI [closed]
...ficial Ninject.Web.Mvc extension. You change your MvcApplication to derive from NinjectHttpApplication, spin up the Kernel in it and call RegisterAllControllersIn(Assembly.GetExecutingAssembly()) to have it take care of all controllers in the given assembly. Magic.
– Michael St...
Unresolved specs during Gem::Specification.reset:
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I was seeing this issue by just running RSpec on its own. From what I understand, this means that you have more than one version of the listed gems installed on your system, and RSpec is unsure which one to use. After uninstalling older version of the gems, the warnings went away.
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