Abstract:
Manipulations of numeric type variables in R are introduced.
Create
a numeric variable
> a=3.43543
> a
[1] 3.43543
Trim
number
>
round(3.43456, digits=2) #Round a number with two digits left
after the dot:
[1] 3.43
> round(3.53456) #
round the number
[1] 4
> floor(3.53456) #
return the smallest integer
[1] 3
> ceiling(3.13) #
return the highest integer
[1] 4
> trunc(3.43543) #
return the integer part
[1] 3
> trunc(3.03543) #
return the integer part
[1] 3
Specify
the format of the number
> a=0.00000003245678
# give a very small value
> a
# here is the default export
[1] 3.245678e-08
> format(a, scientific=T)
#different export format
[1] "3.245678e-08"
> format(a, scientific=F)
[1] "0.00000003245678"
> format(a, scientific=F,
digits=2)
[1] "0.000000032"
> format(a, scientific=T,
digits=2)
[1] "3.2e-08"
Mathematics
> 3.453/4 #
divide
[1] 0.86325
> 3.453*4
#multiply
[1] 13.812
> 3.453+4.5 #plus
[1] 7.953
> 3.453-2.5 #substract
[1] 0.953
> 3.453**3 # 3.453 to
the power of 3
[1] 41.17084
> sqrt(3.453) #the
square root of 3.453
[1] 1.858225
> exp(3.453) #3.453 cubed
[1] 31.59504
> log2(3.453) # logarithm
of 3.453 with the base=2
[1] 1.78785
> log(3.453) # logarithm
of 3.453 with the base=e
[1] 1.239243
> log10(3.453) # logarithm
of 3.453 with the base=10
[1] 0.5381966
Other
operations
> pi
#get pi
[1] 3.141593
> format(pi, digits=10)
[1] "3.141592654"
>
nchar(as.character(235443)) # it is millions
[1] 6
writing
date: 2015.01.27
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