# R program to convert 
# character to expression
  
# Creating an object of character class
x <- "sin(pi / 2)"
  
# Class of object
class(x)
  
# Calling parse() Function
x1 <- parse(text = x)
  
# Class of parsed object
class(x1)

[1] "character"
[1] "expression"

# R program to convert 
# character to expression
  
# Creating an object of character class
x <- "2 ^ 3"
  
# Evaluating the value of object
eval(x)
  
# Calling parse() Function
x1 <- parse(text = x)
  
# Evaluating the value of object
eval(x1)

[1] "2^3"
[1] 8