call In R: The do.call() and call() function

In this article, we will learn about the do.call() function and call() function in R programming language together. Let’s go into detail now.

What is the do.call() and call() function in R?

The do.call() and call() function create an object but the do.call() function executes a function using its name and the specified arguments, and the call() function is not.

Syntax:

do.call(func, list)
call(func, list)

Parameters:

• funct: This identifies the Function to be called and either represents the Function, …
• list: The list of parameters to the function call.

How to use do.call() and call() function in R?

The example of do.call() function

Here, we will use the do.call() function with basic functions. First, we will create data for this example as follows:

# Create a data
data <- c(1:10) * 3

# View a data
data

Output

 [1]  3  6  9 12 15 18 21 24 27 30

We need to use the sum function to determine the vector’s sum. Let’s further assume that the sum function’s Name, sum, is the only thing we have recorded as a character string. The sum function can then be run using the do.call command as seen below:

# Create a data
data <- c(1:10) * 3

# Print the sum of the data
res <- do.call("sum",list(data))
cat("The sum is:",res)

Output

The sum is: 165

Similarly, we can row bind (rbind) data frame columns. See the code example:

# Create a data frame
data1 <- data.frame(
    Math = c(9,8,6),
    English = c(8,6,9)
)

data2 <- data.frame(
    Math = c(5,6,9),
    English = c(8,7,6)
)

data3 <- data.frame(
    Math = c(9,8,6),
    English = c(3,7,6)
)

# The row bind column
cat("The row bind is:\n")
do.call(rbind,list(data1,data2,data3))

Output

The row bind is:
  Math English
1    9       8
2    8       6
3    6       9
4    5       8
5    6       7
6    9       6
7    9       3
8    8       7
9    6       6

The example of call() function

Assume that we want to use the call function to sum the elements of our sample vector data. Following that, we can use as follows:

# Create a data
data <- c(1:10) * 3

# Using call() function
res <- call("sum", data)
res # sum(c(3, 6, 9, 12, 15, 18, 21, 24, 27, 30))

So, we will use the eval function to calculate the sum of this vector.

# Create a data
data <- c(1:10) * 3

# Using call() function
res <- call("sum", data)
res

# Calculate the sum and print
cat("The sum is:",eval(res))

Output

sum(c(3, 6, 9, 12, 15, 18, 21, 24, 27, 30))
The sum is: 165

Another example, we can round numbers by using the call() function.

# Create a data
data <- 3.2

# Round the data
res <- call("round",data) # round(3.2)
cat("The round number is:",eval(res))

Output

The round number is: 3

Summary

This article demonstrates how to use do.call() and call() functions in the R programming language. If you have any questions, please leave a comment below. Thank you for reading!

Have a great day!

Maybe you are interested:

• nchar in R: Get size of the elements in the R object.
• layout In R: Specify A Graphic Layout
• library Function In R: Load A Package

Scott Miller

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