DATA MINING
Desktop Survival Guide by Graham Williams |
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Numbers in R can be integer, double, or
complex. The actual type is generally determined by R
based on context and defaults. Numbers do tend to be double
unless they are in some way restricted to being integers, or you wish
to store http://en.wikipedia.org/wiki/Complex_numbercomplex numbers.
> typeof(1) # "double" > typeof(1.3) # "double" > typeof(1:2) # "integer" - this is a vector of two integers 1 and 2 > typeof((1:2)[1]) # "integer" - this is the first element of the vector > typeof(2+5i) # "complex" - complex numbers have real and imaginary parts |
The basic numeric operators include:
\verb|+| Addition \verb|-| Subtraction \verb|*| Multiplication \verb|/| Division \verb|^| Exponentiation \verb|:| Sequence \verb|%/%| Integer division \verb|%%| Remainder |
> ?Arithmetic |
Typical numeric functions include:
> 1:5 # 1 2 3 4 5 > round(1234.56) # 1235 > trunc(1234.56) # 1234 |