Switch case in R

Switch case

statements are a substitute for long if statements that compare a variable to several integral values. Switch case in R is a multiway branch statement. It allows a variable to be tested for equality against a list of values. Switch statement follows the approach of mapping and searching over a list of values. If there is more than one match for a specific value, then the switch statement will return the first match found of the value matched with the expression.

Syntax:

switch(expression, case1, case2, case3....)

Here, the expression is matched with the list of values and the corresponding value is returned.

Important Points about Switch Case Statements:

• An expression type with character string always matched to the listed cases.
• An expression which is not a character string then this exp is coerced to integer.
• For multiple matches, the first match element will be used.
• No default argument case is available there in R switch case.
• An unnamed case can be used, if there is no matched case.

Flowchart:

Example 1:

# Following is a simple R program  
# to demonstrate syntax of switch.
val <- switch(
   4,
   "Geeks1",
   "Geeks2",
   "Geeks3",
   "Geeks4",
   "Geeks5",
   "Geeks6"
)
print(val)

Output:

[1] "Geeks4"

Example 2:

# Following is val1 simple R program  
# to demonstrate syntax of switch.

# Mathematical calculation

val1 = 6  
val2 = 7
val3 = "s"  
result = switch(  
    val3,  
    "a"= cat("Addition =", val1 + val2),  
    "d"= cat("Subtraction =", val1 - val2),  
    "r"= cat("Division = ", val1 / val2),  
    "s"= cat("Multiplication =", val1 * val2),
    "m"= cat("Modulus =", val1 %% val2),
    "p"= cat("Power =", val1 ^ val2)
)  
  
print(result)  

Output:

multiplication = 42NULL