Learn R – 3 Commands to Generate Random Numbers

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This article represents 3 different commands with code examples which could be used to generate random numbers in R programming language. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos.

Following are the key points described later in this article:

  • Runif command
  • Sample command
  • Rnorm command
  • Difference between runif and rnorm command
Runif: Generate Random Numbers based on Uniform Distribution

“Runif” command can be used for generating random numbers based on uniform distribution. One can generate one or more random numbers within a range of numbers. One should note that the random numbers generated using runif commands are all decimal (non-integers) numbers.

# Generate 5 random numbers
runif(5)

# Generate 5 random numbers (Non-integers) between 2 and 7
runif(5, 2, 7)

 

Sample: Generate Random Numbers based on Uniform Distribution

“Sample” command is also used for generating random numbers based on uniform distribution. One can generate one or more random numbers within a range of numbers. One should note that the random numbers generated using runif commands are all integer numbers. This is the key difference between runif and sample command.

# Generate 5 random numbers (Integers)
sample(5)

# Generate 5 random numbers (Integers) between 2 and 7; Duplicates are allowed
# with replace parameter set to True (T)
sample(2:7, 5, replace=T)

# Generate 5 random numbers (Integers) between 2 and 7; Duplicates are NOT allowed
# with replace parameter set to False (F)
sample(2:7, 5, replace=F)

# Generate 5 country names from the vector countryNames with replace as false
countryNames <- c("India","USA","Pakistan","China","Japan","South Korea","Mangolia")
sample(countryNames, 5)

 

Rnorm: Generate Random Numbers based on Normal Distribution

“Rnorm” command is used for generating random numbers based on normal distribution.

# Generate 5 random numbers with mean as 0 and standard deviation as 1
rnorm(5)

# Generate 5 random numbers with mean as 5 and standard deviation as 2
rnorm(500, mean=5, sd=2)

 

Random Number Generation for Uniform & Normal Distribution

The key difference between runif/sample and rnorm command is following:

  • runif/sample command generates the random numbers based on uniform distribution
  • rnorm command generates random numbers based on normal distribution

 

Ajitesh Kumar

Ajitesh Kumar

Ajitesh has been recently working in the area of AI and machine learning. Currently, his research area includes Safe & Quality AI. In addition, he is also passionate about various different technologies including programming languages such as Java/JEE, Javascript and technologies such as Blockchain, mobile computing, cloud-native technologies, application security, cloud computing platforms, big data etc.

He has also authored the book, Building Web Apps with Spring 5 and Angular.
Ajitesh Kumar

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