Loops (R Loops) are used to repeat the execution of a block of statements based on some predefined conditions. In R Programming we have the following types of loops that can be used as per development requirements.

Repeat Loop in R Programming

Repeat loop in R executes the set of statements until the defined condition is satisfied

1. #Print some value using Repeat Loop
2. count <- 1
4. repeat {
5. print("R Programming")
6. count <- count+1
8. if(count > 5) {
9. break
10. }
11. }

and output is

1. [1] "R Programming"
2. [1] "R Programming"
3. [1] "R Programming"
4. [1] "R Programming"
5. [1] "R Programming"

Another Example

1. #Print table of 10 using Repeat Loop
2. a <- 10
3. count <- 1
5. repeat {
6. print(a*count)
7. count <- count+1
9. if(count > 10) {
10. break
11. }
12. }

and output is

1. [1] 10
2. [1] 20
3. [1] 30
4. [1] 40
5. [1] 50
6. [1] 60
7. [1] 70
8. [1] 80
9. [1] 90
10. [1] 100

While Loop in R Programming

While loop checks the condition before starting loop execution and executes the set of statements while the defined condition is true.

1. #Declare and Initialise a varable
2. a <- 1
4. #Check condition in a while loop
5. while(a<=5){
6. print(a)
7. a <- a+1
8. }

and output is

1. [1] 1
2. [1] 2
3. [1] 3
4. [1] 4
5. [1] 5

FOR Loop in R Programming

When you need to execute a code a specific number of times then FOR loop comes into action. Here we'll see how to iterate a vector using FOR loop.

1. #Declare and Initialise a Vector
2. a <- c(10,TRUE,"Ashish",2.4)
4. #Iterate vector using FOR loop
5. for(i in a){
6. print(i)
7. }

and output is

1. [1] "10"
2. [1] "TRUE"
3. [1] "Ashish"
4. [1] "2.4"

Cheers 🙂 Happy Learning

R Decision Making - IF...ELSE Statement in R Programming

We can write a simple IF statement, IF...ELSE statements or nested IF statements as per our requirement. If you know the basics of any other programming language then after this tutorial you'll get an idea about writing conditional statements in R programming.

Flow Chart of IF...ELSE is like this

Basic Syntax of IF-ELSE is like this in R

IF (Condition 1){
Statement to execute (if condition 1 is true)
}ELSE IF (Condition 2){
Statement to execute (if condition 2 is true)
}ELSE
Statement to execute (if condition 1& 2 both are false)

For a better understanding of decision-making, statements see this example

> #Declare Variables
> a <- 20
> b <- 40
> c <- 5
> 
> #Check conditions
> if(a>b && a>c){
+ print("Largest Value is A")
+ 
+ }else if(b>a && b>c){
+ print("Largest Value is B")
+ 
+ }else print("Largest Value is C-")
[1] "Largest Value is B"
>

This is how IF…ELSE works in R programming.

Cheers 🙂 Happy Learning

R Operators – Arithmetic Operators, Relational Operators, Logical Operators

 In programming, an operator is a symbol that is used to perform any specific mathematics or logical operation. In simple language, we can say that the operator is used to perform some operations and like other programming languages R has a set of various types of R operators that can be divided into the following categories.

 

• Arithmetic Operator
• Relational Operator
• Logical Operator
• Assignment Operator

Arithmetic Operators in R

Arithmetic operators are used for performing mathematical operations like addition, subtraction etc.

Operator	Description
+	Addition (To Add two variables in R)
-	Subtraction (To Subtract one variable from another)
*	Multiplication (To Multiply variables)
/	Division (To divide the first variable with the second)
^	Exponent (The first variable's value raised to the exponent of second value)
%%	Modulus (Gives the remainder of the first variable's value with the second)

See an example here

> # An addition
> 5 + 10 
[1] 15
> 
> # A subtraction
> 10 - 5 
[1] 5
> 
> # A multiplication
> 5 * 15
[1] 75
> 
> # A division
> 12 / 2 
[1] 6
> 
> # Exponentiation
> 2^6
[1] 64
> 
> # Modulus
> 25%%4
[1] 1
>

Relational Operators in R

Relational Operators are used for comparing values and produce a boolean result.

Operator	Description
>	Greater than
<	Less than
>=	Greater than or equal to
<=	Less than or equal to
==	Equal to
!=	Not equal to

See an example here

> # Greater than
> a <- 10
> b <-20
> print(b>a)
[1] TRUE
> 
> # Less than
> a <- 10
> b <-20
> print(b<a)
[1] FALSE
> 
> # Greater than or equal to
> a <- c(10,20,5)
> b <- c(20,10,5)
> print(b>=a)
[1] TRUE FALSE TRUE
> 
> # Less than or equal to
> a <- c(10,20,5)
> b <- c(20,10,5)
> print(b<=a)
[1] FALSE TRUE TRUE
> 
> # Equal to
> a <- 10
> b <-10
> print(b==a)
[1] TRUE
> 
> # Not equal to
> a <- 10
> b <-10
> print(b!=a)
[1] FALSE

Logical Operators in R

The logical operators are used to carry out boolean operations between variables. Number zero (0) is considered FALSE and all numbers greater than 0 are considered TRUE.

Operator	Description
&	Element wise logical AND (It checks each value of both vector and gives output TRUE if both values are TRUE)
|	Element wise logical OR (It checks each value of both vector and gives output TRUE if any one value is TRUE)
!	Logical NOT (It takes each value of vector and reverse it's logical value)
&&	Logical AND (It checks only first value of both vector and gives output TRUE if both values are TRUE)
||	Logical OR (It checks only first value of both vector and gives output TRUE if any of them are TRUE)

See an example here

> #Take two vectors
> a <- c(0,20,30,0,FALSE)
> b <- c(12,23,42,0,TRUE)
> 
> #Print Element wise logical AND
> print(a&b)
[1] FALSE  TRUE  TRUE FALSE FALSE
> 
> #Print Element wise logical OR
> print(a|b)
[1]  TRUE  TRUE  TRUE FALSE  TRUE
> 
> #Print Logical AND
> print(a&&b)
[1] FALSE
> 
> #Print Logical OR
> print(a||b)
[1] TRUE
> 
> #Print Logical NOT
> print(!a)
[1]  TRUE FALSE FALSE  TRUE  TRUE
> print(!b)
[1] FALSE FALSE FALSE  TRUE FALSE
>

Assignment Operators in R

Learn more about R assignment operators here

Cheers :) Happy Learning