In this guide we will discuss about R else if statement. This statement is also known as nested if-else statement. The if statement is followed by an optional else if….. else statement. This statement is used to test various condition in a single if……else if statement. There are some key points which are necessary to keep in mind when we are using the if…..else if…..else statement. These points are as follows:
- if statement can have either zero or one else statement and it must come after any else if’s statement.
- if statement can have many else if’s statement and they come before the else statement.
- Once an else if statement succeeds, none of the remaining else if’s or else’s will be tested.
The basic syntax of If-else statement is as follows:
if(boolean_expression 1) {
// This block executes when the boolean expression 1 is true.
} else if( boolean_expression 2) {
// This block executes when the boolean expression 2 is true.
} else if( boolean_expression 3) {
// This block executes when the boolean expression 3 is true.
} else {
// This block executes when none of the above condition is true.
}
Flow Chart
Example 1
age <- readline(prompt="Enter age: ")
age <- as.integer(age)
if(age<18)
print("You are child")
else if(age>30)
print("You are old guy")
else
print("You are adult")
Output:
Example 2
marks=83;
if(marks>75){
print("First class")
}else if(marks>65){
print("Second class")
}else if(marks>55){
print("Third class")
}else{
print("Fail")
}
Output:
Example 3
cat("1) For Addition\n")
cat("2) For Subtraction\n")
cat("3) For Division\n")
cat("4) For multiplication\n")
n1<-readline(prompt="Enter first number:")
n2<-readline(prompt="Enter second number:")
choice<-readline(prompt="Enter your choice:")
n1<- as.integer(n1)
n2<- as.integer(n2)
choice<- as.integer(choice)
if(choice==1){
sum <-(n1+n2)
cat("sum=",sum)
}else if(choice==2){
sub<-(n1-n2)
cat("sub=",sub)
}else if(choice==3){
div<-n1/n2
cat("Division=",div)
}else if(choice==4){
mul<-n1*n2
cat("mul=",mul)
}else{
cat("wrong choice")
}
Output:
Example 4
x <- c("Hardwork","is","the","key","of","success")
if("Success" %in% x) {
print("success is found in the first time")
} else if ("success" %in% x) {
print("success is found in the second time")
} else {
print("No success found")
}
Output:
Example 5
n1=4
n2=87
n3=43
n4=74
if(n1>n2){
if(n1>n3&&n1>n4){
largest=n1
}
}else if(n2>n3){
if(n2>n1&&n2>n4){
largest=n2
}
}else if(n3>n4){
if(n3>n1&&n3>n2){
largest=n3
}
}else{
largest=n4
}
cat("Largest number is =",largest)
Output:
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