The length() function is used to calculate the length of vectors or any other R object.
Syntax
length(data)
Parameters
data (required): It accepts data that can be either vector, factor, list, or other objects.
Return Value
It returns the size of an R object.
Example 1: Finding the length of a vector
vec <- 1:5
cat("The length of vector is:", length(vec), "\n")
Output
The length of vector is: 5
Here, we defined a vector that returns the length; otherwise, the length returns NA.
Example 2: Usage with a list
main_list <- list(c(1, 2, 3, 4))
cat("The length of list is:", length(main_list), "\n")
Output
The length of list is: 1
From the output, you can see that we did not get the length of each list element. Instead, it returns the number of entries on our list.
To get the length of a single list element, use this code:
main_list <- list(c(1, 2, 3, 4))
cat("The length of single list element is:", length(main_list[[1]]), "\n")
Output
The length of single list element is: 4
Example 3: Usage with a Data Frame
If you use the length() function on the data frame, it will return the number of columns in the data frame.
df <- data.frame(
col1 = c(1, 2, 3),
col2 = c(4, 5, 6),
col3 = c(7, 8, 9)
)
length(df)
Output
[1] 3
The length() is different from nrow() and ncol(), which return the number of rows and columns of a matrix or data frame, respectively.
Example 4: Usage with a string
If you pass a string to the length(), it will return a value of 1.
str <- "Krunal"
length(str)
Output
[1] 1
To count the characters of a string, you can use the “nchar()” function.
str <- "Krunal"
nchar(str)
Output
[1] 6
For multi-dimensional arrays, length() will return the total number of elements across all dimensions.
Krunal Lathiya is a seasoned Computer Science expert with over eight years in the tech industry. He boasts deep knowledge in Data Science and Machine Learning. Versed in Python, JavaScript, PHP, R, and Golang. Skilled in frameworks like Angular and React and platforms such as Node.js. His expertise spans both front-end and back-end development. His proficiency in the Python language stands as a testament to his versatility and commitment to the craft.