In this article, we will discuss how to generate a sample using the sample function in R.
Sample() function is used to generate the random elements from the given data with or without replacement.
Syntax:
sample(data, size, replace = FALSE, prob = NULL)
where,
- data can be a vector or a dataframe
- size represents the size of the sample
- replace is used to set the values again repeated if it is set to true
- prob: a vector of probability weights for obtaining the elements of the vector being sampled
Example 1: Generate sample data from the vector
Here, we will generate the n sample data from the given vector with 11 elements using the sample function.
# consider the vector
data=c(23,45,21,34,5,6,7,8,86,45,3)
# get 4 random elements
print(sample(data,4))
# get 1 random element
print(sample(data,1))
# get 6 random elements
print(sample(data,6))
Output:
[1] 45 7 5 34 [1] 3 [1] 5 23 8 21 6 45
Example 2: Generate sample data from the vector by replacing
Here we are going to create a vector with 11 elements and generate the sample data with a replacement.
# consider the vector
data=c(23,45,21,34,5,6,7,8,86,45,3)
# get 4 random elements
print(sample(data,4,replace=TRUE))
# get 1 random element
print(sample(data,1,replace=TRUE))
# get 6 random elements
print(sample(data,6,replace=TRUE))
Output:
[1] 45 5 5 3 [1] 86 [1] 5 5 8 7 8 45
Example 3: Sampling with Uneven Probabilities Using sample Function
Here we are going to select the elements with higher probability than others by setting the probability using the prob parameter.
# consider the vector
data=c(23,45,21,34,5)
# get 10 random elements with probability
print(sample(data, size = 10, replace = TRUE,
prob = c(0.6,0.1,0.1,0.1,0.1)))
Output:
[1] 23 23 23 23 23 45 23 23 23 23
Example 4: Random Sampling of Data Frame Rows Using sample Function
Here we are going to sample the dataframe, let us create a dataframe and sample the rows.
# create dataframe with 2 columns
data=data.frame(col1=c(1:10),col2=c(12:21))
# get the sample of 4 in each column
data[sample(1:nrow(data), size = 4), ]
Output:
Example 5: Random Sampling of List Elements Using sample Function
Here we are going to sample the data in the list with size 4
# create list with some integers
data=list(1,2,3,4,5,6)
# get the sample of 4
data[sample(1:length(data), size = 4)]
Output:
[[1]] [1] 2 [[2]] [1] 1 [[3]] [1] 4 [[4]] [1] 6
