What is the Switch Case statement in R?

Switch-Case()

The switch case statement compares the expression value with the values in the list and returns the output. The primary purpose of the switch function is to provide a way to handle multiple conditions.

A switch function mainly provides two ways of selecting cases based on an expression.

Based on Index

This method matches the expression with the cases based on their numeric positions. If the expression is matched, the corresponding code block will be executed.

Syntax

switch(expression, value1, value2, value3, …)

Example

Below is an example of a switch statement that will show you the use of a switch statement based on an index.

Code

a = 2
b= 1
x = switch(
	a+b,  
	"Abhishek",
	"Sam",
	"Vipin",
	"Ishan"
)
print(x)

Output

Explanation

In the above example, you can see that the output is "Vipin". We have to variable a and b with values 2 and 1, respectively. Now in the expression, we are passing a+b, which is 2+1 equal to 3. So, in the available cases, it will return the code block of 3rd index, which is "Vipin."

Based on the Matching Value

In this method, the switch function matches the expression with the cases based on the matching value.

Syntax

switch(expression, case1= value1, case2= value2, …)

Example

Below is an example of a switch statement giving an output by matching the expression value with the cases.

Code

x = "Gn"
y = switch(  
	x,  
	"Gm" = "Good Morning",
	"Ga" = "Good Afternoon",
	"Ge" = "Good Evening",
	"Gn" = "Good Night"
)
print(y) 

Output

Explanation

In the above example, we assigned the value "Gn" to the x variable. Then we use the switch cases to find the matching value of x. In the fourth case, you can see that the x value is matched with the case. So, it will stop searching and return the "Good Night" output.

Comparison With If-else Statements

Let’s see the comparison between the switch and the if-else statement with the help of some points.

• Switch statements make concise code for multiple cases. While if-else statements provide flexibility to handle complex and nested conditions.
   
• Switch statements improved the code readability for a large number of cases. The if-else statement has the ability to evaluate logical expressions and able to perform a wider range of operations.
   
• Switch statements execute faster by directly moving to the relevant statement, while If else is suitable for complex comparison cases.
   
• The switch is best suited for discrete variables. While if else can handle continuous variables with relational operations.
   
• In Switch, you can easily add new cases without modifying the existing code. In the if-else statement, it is hard to add new cases because you have to check the existing code, and maybe modification occurs.

Frequently Asked Questions

How does the switch case statement work?

Switch case evaluates an expression and matches it with the multiple cases to execute the corresponding code block.

Can we use multiple expressions in the switch case statement?

No, the switch case statement in R does not allow multiple expressions. The switch statement in R evaluates a single expression to determine the matching case.

Does the switch case statement have a default case?

The switch case statement does not have a built-in default case.

How is the switch case statement different from the if-else statement?

The switch statement is helpful when you have multiple conditions to evaluate against a single expression. On the other hand, the if-else statement is more useful when there are few conditions or require logical expressions.

Are there any limitations to using the switch statement in R?

Yes, switch case statements do not support pattern matching. It matches the expression from top to bottom. Once a matching case is found, it executes the corresponding code block.

Conclusion

In this blog, we discussed the switch case statement in R with the help of examples. We hope this blog helped you to enhance your learning on switch case statements. Check the below articles to know more.

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