What are the Keywords in R Language?

Keywords in R Language

Like all other programming languages, R language has some keywords that cannot be used as variable or function names. This section will discuss some of the essential keywords in the R language.

if

"if" is a decision-making keyword in the R programming language. This keyword decides whether a particular code block will be executed depending on a specific condition.
 

Syntax:

if ( condition ) {
	....Code block....
}

else

"else" is also a decision-making keyword in the R programming language. The main difference between the if and the else keyword is that the else keyword can't be used independently. On the other hand, we can use the if keyword independently without the if keyword.
 

Syntax:

if ( condition ) {
	....Code block 1....
}

else {
	....Code block 2....
}

for

"for" is also an essential keyword in R programming. This keyword is used to create loops that can iterate for a fixed amount of times.
 

Syntax:

for ( variable in start:end ){
	....Code block....
}

The above syntax variable is the iterating variable, and [start, end] is the for-loop range.

while

"while" is a type of control statement that runs a code block repeatedly until the condition becomes false.
 

Syntax:

while( condition ){
…….Code block…….
}

break

"break" is a type of jump statement used to terminate or jump out of the loop.
 

Syntax:

while ( condition 1 ){
	....Code block 1....
	if ( condition 2 ){
		....Code block 2....
		break;
	}
}

repeat

Like the while and the for keywords, repeat is also used to run a code block repeatedly. The difference between repeat and other loop statements is that to exit a repeat statement; we have to set the break condition inside the code block.
 

Syntax:

repeat {
	....Code block 1....
	if (break condition ){
		....Code block 2....
		break;
	}
}

function

The "function" keyword is used to declare functions in the R language. This keyword is used before the function body to express the function.
 

Syntax:

func1 = function ( condition ) {
	....Code block....
}

next

The "next" keyword is used in loop statements to skip the current iteration of the loop and continue to the next iteration. This keyword is similar to the "continue" keyword in other languages.
 

Syntax:

for ( var in start:end) {
	if ( condition ){
		....Code block....
		next
	}
}

TRUE/FALSE

The True and False keywords represent boolean values in the R language. If the condition is satisfied, then the interpreter returns true. Otherwise, it returns false.
 

Syntax:

var1 = (condition)

If the condition is true, the value of var1 will be set to TRUE, else it will be set as FALSE. 

Example

An example code to demonstrate the use of each of the above keywords is shown below.
 

Code

age <- 19

# use of if else keywords
if (age >=18) {
	print("You are eligible to get a driver's license.")
}
else {
	print("You are not eligible to get a driver's license.")
}

# use of for and while loops
for( i in 1:5 ){
	print(paste("You are candidate number:", i))
}

i <- 1
while (i<=5) {
	print(paste("You are candidate number:", i))
	i <- i+1
}

#use of repeat keyword
i <- 1
repeat {
	print(paste("You are candidate number:", i))
	i <- i+1
	if (i>5) {
		# use of break statement
		break;
	}
}

myFunc <- function (a, b) {

	# use of bool keyword
	res <- (a<b)
	return (res)
}

myFunc(10, 5)
myFunc(3, 5)

Output

Best Practices for Using Keywords in R Language

In the previous section, we discussed the keywords in the R language. In this section, we will look at some tips we should follow while using keywords in the R language.
 

• Naming Conventions - While naming variables, we should stick to the naming conventions of the programming language. For example, many programming languages use camel case capitalization in naming their variables.
   
• Language-specific- Some keywords are only available in a few particular programming languages. We must adequately use these keywords to avoid syntax errors.
   
• Case-sensitivity - In some programming languages (including R), keywords are case-sensitive. We should carefully check the capitalization while using keywords in R programming.
   
• Compatibility - While using keywords, we should check the cross-platform compatibility of keywords. If we need to run our program on multiple platforms, the keywords should not have any platform restrictions.
   
• Scope and Visibility - Keywords can have limited visibility depending on their scoping rules. We should keep these constraints in mind while using these keywords.

Frequently Asked Questions

Is it possible to generate user-defined keywords in R language?

No, generating user-defined keywords in the R programming language is impossible. Instead of keywords, we can use user-defined identifiers in our code to modify our program.

What are the key features of Keywords in programming?

Keywords are unique predefined words reserved for internal use in a programming language. Keywords are unique, case-sensitive, defined scope, have dedicated memory in the program, and cannot be overridden by the user.

How many Keywords are present in R language

There are a total of twenty-one keywords in the R language. These keywords include if, else, while, for, break, next, repeat, NULL, TRUE, function, Inf, NA, in, NaN, etc.

Conclusion

In this article, we discussed keywords in programming and their importance. We discussed some of the essential keywords in R language with code examples. In the end, we concluded by briefly discussing some best practices to keep in mind while using keywords and some frequently asked questions. 

So now that you have learned about keywords in R language, you can refer to similar articles.
 

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You may refer to our Guided Path on Code Studios for enhancing your skill set on DSA, Competitive Programming, System Design, etc. Check out essential interview questions, practice our available mock tests, look at the interview bundle for interview preparations, and so much more!

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