[R] R code help!

Adams, Jean jvadams at usgs.gov
Sat Sep 19 19:02:26 CEST 2015


Here's one way to save your results, using a list of lists and a for() loop.

nsim <- 100
outputs <- vector("list", nsim)
for(i in 1:nsim) {
  outputs[[i]] <- sim.f(p.s=.05, N=1000, sample.size=69, n.sim=500)
}

Jean

On Fri, Sep 18, 2015 at 2:27 PM, SH <emptican at gmail.com> wrote:

> Dear R users,
>
> I am trying to simulate surveys and the survey result will be used to
> determine the population to be "accepted" or "rejected".  With the results,
> I would like to calculate cumulative means and plot them to see if a
> converged value is as expected.  Below is R-code I generated.  I need a
> help to repeat this simulation code as many times (e.g., 100) and keep the
> results as list format if possible.  Could you give me any insight?
>
> Thanks  a lot in advance,
>
> Steve
>
> sim.f <- function(p.s, N, sample.size, n.sim) {
> pop = sampled.pop = decision = decisionB = cum.mn = as.list(NULL)
> for(i in 1:n.sim) {
>    p <- c(rep(1, p.s*N), pop2 <- rep(0, N*(1-p.s))) # Generate sample space
>    pop[[i]] <- sample(p) # Randomization sample space
>    sampled.pop[[i]] <- sample(pop[[i]], sample.size)# Random sampling
>    decision[i] <- ifelse(sum(sampled.pop[[i]])>=1, 'Reject','Pass') #
> Decision for each group of n.sim
>    decisionB <- ifelse(decision == 'Reject', 1, 0) # Convert to binary
>    cum.mn <- cumsum(decisionB) / seq_along(decisionB) # Cummulative mean
> of
> n.sim group decisions
>    }
> result = list(population=pop,
>   pop_sub = sampled.pop,
>   decision = decision,
>   decisionB = decisionB,
>   cum.mn = cum.mn)
> }
> sim.out <- sim.f(p.s=.05, N=1000, sample.size=69, n.sim=500)
> # I want to repeat this simulation function for example 100 times or and
> also #keep the data so that I can explore later.  If it is not possible to
> keep all #outputs, at least I would like to have cum.mn outputs.
>
> summary(sim.out)
> sim.out$population
> sim.out$pop_sub
> sim.out$decision
> sim.out$decisionB
> y1 <- sim.out$cum.mn
> #plot(y1, type='l')
> lines(y2, type='l')
> ...
> lines(y100, type='l')
> abline(h=.95, col='red')
>
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>
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