# R for Data Science – Part 4 – Operators and Conditional Statements

Operators and Conditional statements

This is the fourth part of the series “R for Data Science”. The series is as follows:

R Operators

R consists of different operators for performing different mathematical and logical operations.
Operators in R are mainly classified into the following categories:

1. Arithmetic Operators
2. Relational Operators
3. Logical Operators
4. Assignment Operators

Arithmetic Operators

These operators are used for performing mathematical operations like addition, subtraction and multiplication etc. Following list shows the arithmetic operators can be used in R:

 Operator Description + Addition – Subtraction * Multiplication / Division ^ Exponent %% Modulus %/% Integer division

Examples are:

```>x <- 10

> y <- 15

> x+y

[1] 25

#Subtraction

> x-y

[2] -5

#Multiplication

> x*y

[3] 150

#Division

> y/x

[4] 1.5

#Modulus

> y%%x

[5] 5

#Exponent

> y^x

[6] 576650390625

#Integer Division

> y%/%x

[7] 1```

Relational Operators

Relational operators are used for comparing between values. Following list shows the relational operators can be used in R:

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

Examples are:

```> x <- 10
> y <- 15

#Greater Than

> x>y

[1] FALSE

#Greater Than or Equal to

> x>=10

[2] TRUE

#Lesser than

> x<y

[3] TRUE

#Lesser than or Equal to

> y<=12

[4] FALSE

#Exactly equal to

> y==15

[5] TRUE```

Logical Operators

Logical operators are used to perform Boolean operations like AND, OR etc.

 Operator Description ! Logical Not && Logical AND || Logical OR

Examples are:

```#|| Operator

> c(TRUE, TRUE, FALSE) || c(TRUE, FALSE, FALSE)

[1] TRUE

#&& Operator

> c(TRUE, 0, TRUE) && c(TRUE, FALSE, FALSE)

[2] TRUE```

Assignment Operators

These operators are used to assign values to variables.

 Operator Description <-,= Leftwards Assignment -> Rightwards Assignment

Examples are:

```#Leftwards Assignment

> x <- 5

> x

[1] 5

#Rightwards Assignment

> 10 -> x

> x

[2] 10```

Conditional Statements

Like other programming languages, R provides decision making features through conditional statements. Conditional Statements consist of:

1. If statement
2. If-else statement
3. Nested if-else statement

If Statement

The if statement allows a block of code to be executed if and only if the condition provided in if statement is true. The syntax of if statement is:

if (condition) {

statement

}

Its example is:

```p<-10

if(p>5){

print("Number is greater than 5")

}```

Output

`[1] "Number is greater than 5"`

If else statement

In this if the condition is TRUE, the statement within the if block gets executed and if the condition is FALSE, the statement in the else block is executed. It is necessary for the ‘else’ keyword to be in the same line where the closing brace of if statement is displayed. The syntax for this decision statement is:

if(condition) {

statement1

}

else{

statement2

}

The example for if else is:

```x <--1

if(x >0){

print("Positive number")

}

else{

print("Negative number")

}```

Output

`[1] "Negative number"`

Nested if else statement

To use more than one condition, we use nested if else. Its syntax is:

if( condition1){

statement1

}

elseif(condition2){

statement2

}

elseif(condition3){

statement3

}

else

statement4

The nested if else can be easily understood with the following example:

```x <-0

if(x <0){

print("Negative number")

}

elseif(x >0){

print("Positive number")

}

else

print("Zero")```

Output

`[1] "Zero"`

This is all for the lesson and now you can try these Operators and Condition Statements in R.

Please do comment if you have any query or doubt regarding the topic. Till then Happy Learning!