Check if an Object is an Expression in R Programming – is.expression() Function

is.expression() function in R Language is used to check if the object passed to it as argument is of the expression class.

Syntax: is.expression(object)

Parameters:
object: Object to be checked

Example 1:

# R program to check if
# an object is an expression

# Creating an object
x <- "sin(pi / 2)"

# Printing value of the object
eval(x)

# Calling is.expression() function
is.expression(x)

Output:

[1] "sin(pi/2)"
[1] FALSE

Example 2:

# R program to check if
# an object is an expression

# Creating an object
x <- expression(sin(pi / 2))

# Printing value of the object
eval(x)

# Calling is.expression() function
is.expression(x)

Output:

[1] 1
[1] TRUE