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rprogramming-languagessimulationmontecarlo
Twk Wei Keong
Twk Wei Keong

Reputation: 23

R programming (Monte Carlo Simulation)

Hi I would like to ask how to sample out 50 instances of iris data (which contain 150 instances) by using Monte Carlo Simulation ? Any idea? Many thanks

Upvotes: 1

Views: 1052

Answers (2)

hpesoj626
hpesoj626

Reputation: 3619

Here is one way to do it in base R.

You can sample 50 rows with replacement with

iris[sample(1:nrow(iris), size = 50, replace = TRUE), ]

To make a list, e.g., of 1000 samples of 50 rows with replacement, you can use lapply.

iris_mc_samps <- lapply(1:1000, function(x) iris[sample(1:nrow(iris), size = 50, replace = TRUE), ])

Upvotes: 1

www
www

Reputation: 39154

We can use sample_n from to select 50 rows with replacement.

# Set seed for reproducibility
set.seed(12800)

library(dplyr)
library(purrr)

iris_sub <- iris %>% sample_n(size = 50, replace = TRUE)

And here I show one approach that can repeat this process for 1000 times, using map_dfr from the package. The end result is a data frame with 50000 rows. A new column called Time is created to document the number of sampling.

iris_sample <- map_dfr(1:1000, ~iris %>%
                         sample_n(size = 50, replace = TRUE) %>%
                         mutate(Time = .x))

Upvotes: 3

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