Database Reference

In-Depth Information

In quite a few simulations, we need to generate random numbers. R has a compre-

hensive library of functions to do this. Use
runif
to generate multiple random num-

bers uniformly between two numbers. Have a look at the following example:

runif(1, 2, 3)

runif(10, 5.0, 7.5)

Of course, every time you get a different number. The sample function generates an

integer random number between numbers:

sample(1:10, 5, replace=T)

The first argument is a vector of valid numbers to generate (here, the numbers are

1 to 10), the second argument indicates numbers to be returned, and the third argu-

ment states that once a number is generated, R can still use that number in future

generations. So, a true there means you may see the same random number more

than once. The default is
replace=F
. In such cases, there will not be a repetition.

The most basic data type in R and is called a
Vector
.

The following commands show a set of interesting operations on vectors:

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