How to Apply the sample() Function in R (4 Examples)
In this tutorial you’ll learn how to take a simple random sample in the R programming language.
Example 1: Take Subsample of Alphabet
set.seed(951951) # Setting seed |
set.seed(951951) # Setting seed
sample(LETTERS, # Sampling ten letters 10) # "N" "Y" "C" "E" "Q" "H" "U" "B" "G" "S" |
sample(LETTERS, # Sampling ten letters 10) # "N" "Y" "C" "E" "Q" "H" "U" "B" "G" "S"
Example 2: Take Subsample with Replacement
sample(LETTERS, # Sampling with replacement 10, replace = TRUE) # "A" "B" "I" "W" "O" "H" "E" "A" "T" "V" |
sample(LETTERS, # Sampling with replacement 10, replace = TRUE) # "A" "B" "I" "W" "O" "H" "E" "A" "T" "V"
Example 3: Adjusting Probabilities of Sample Units
sample(LETTERS, # Changing sample probabilities 10, replace = TRUE, prob = c(75, rep(1, 25))) # "A" "A" "A" "A" "A" "B" "A" "A" "A" "Q" |
sample(LETTERS, # Changing sample probabilities 10, replace = TRUE, prob = c(75, rep(1, 25))) # "A" "A" "A" "A" "A" "B" "A" "A" "A" "Q"
Example 4: Subsampling Rows of Data Frame
data(iris) # Iris data set head(iris) # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 1 5.1 3.5 1.4 0.2 setosa # 2 4.9 3.0 1.4 0.2 setosa # 3 4.7 3.2 1.3 0.2 setosa # 4 4.6 3.1 1.5 0.2 setosa # 5 5.0 3.6 1.4 0.2 setosa # 6 5.4 3.9 1.7 0.4 setosa |
data(iris) # Iris data set head(iris) # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 1 5.1 3.5 1.4 0.2 setosa # 2 4.9 3.0 1.4 0.2 setosa # 3 4.7 3.2 1.3 0.2 setosa # 4 4.6 3.1 1.5 0.2 setosa # 5 5.0 3.6 1.4 0.2 setosa # 6 5.4 3.9 1.7 0.4 setosa
iris[sample(1:nrow(iris), 3), ] # Subsampling rows of data # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 86 6.0 3.4 4.5 1.6 versicolor # 123 7.7 2.8 6.7 2.0 virginica # 35 4.9 3.1 1.5 0.2 setosa |
iris[sample(1:nrow(iris), 3), ] # Subsampling rows of data # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 86 6.0 3.4 4.5 1.6 versicolor # 123 7.7 2.8 6.7 2.0 virginica # 35 4.9 3.1 1.5 0.2 setosa