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How do I make a matrix from a list of vectors in R?
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One option is to use do.call():
> do.call(rbind, a)
[,1] [,2] [,3] [,4] [,5] [,6]
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Remove last item from array
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Use splice(startPosition, deleteCount)
array.splice(-1,1)
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使用std::string作为std::map的key出错解决 - C/C++ - 清泛网 - 专注C/C++及内核技术
...std::map的key出错解决c: program files (x86) microsoft visual studio 11.0 vc include xstddef(180): error C2784: bool std::operator <(const st...c:\program files (x86)\microsoft visual studio 11.0\vc\include\xstddef(180): error C2784: “bool std::operator <(const std::_Tree<_Traits> &,const...
How to compare software version number using js? (only number)
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What is the Ruby (spaceship) operator?
...roovy is another language that supports it. Basically instead of returning 1 (true) or 0 (false) depending on whether the arguments are equal or unequal, the spaceship operator will return 1, 0, or −1 depending on the value of the left argument relative to the right argument.
a <=> b :=
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Apply a function to every row of a matrix or a data frame
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182
You simply use the apply() function:
R> M <- matrix(1:6, nrow=3, byrow=TRUE)
R> M
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What is the most efficient/elegant way to parse a flat table into a tree?
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14 Answers
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Replace all 0 values to NA
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Replacing all zeroes to NA:
df[df == 0] <- NA
Explanation
1. It is not NULL what you should want to replace zeroes with. As it says in ?'NULL',
NULL represents the null object in R
which is unique and, I guess, can be seen as the most uninformative and empty object.1 Then it b...