[R] better loop for simulation

[Dalthorp, Daniel]

try:

n.questions <- 10  # or however many you want
mult.choice <- 2
scores <- rbinom(1000, size = n.questions, prob = 1/mult.choice)


On Sat, Jun 18, 2016 at 3:12 PM, Naresh Gurbuxani <
naresh_gurbuxani at hotmail.com> wrote:

> I want to calculate a function many times over.  My solution below works,
> but does not seem very elegant.
>
> # my function to run many times over
> stud.score <- function(n.questions, mult.choice = 2) {
>         prob.success <- 1 / mult.choice
>         answers <- (runif(n.questions) < prob.success)
>         return(sum(answers))
> }
>
> # my method to run above function 1000 times and store results
> count.df <- data.frame(n.count = rep(10, 1000))
> scores.df <- apply(count.df, 1, function(x) return(stud.score(x)))
>
> Creating a data frame just to repeat the the count seems wasteful.  How
> can I generate scores.df without count.df?
>
> Thanks,
> Naresh
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-- 
Dan Dalthorp, PhD
USGS Forest and Rangeland Ecosystem Science Center
Forest Sciences Lab, Rm 189
3200 SW Jefferson Way
Corvallis, OR 97331
ph: 541-750-0953
ddalthorp at usgs.gov

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