R Tutorial

Fundamentals of R

Variables

Input and Output

Decision Making

Control Flow

Functions

Strings

Vectors

Lists

Arrays

Matrices

Factors

DataFrames

Object Oriented Programming

Error Handling

File Handling

Packages in R

Data Interfaces

Data Visualization

Statistics

Machine Learning with R

Control Statements in R

Control statements in programming are used to dictate the flow of execution based on certain conditions or loops. R, like other programming languages, offers a suite of control statements to facilitate this. This tutorial will cover the basics of control statements in R, including conditional statements and loops.

1. Conditional Execution

a. `if` statement:

The basic if statement checks a condition and executes the associated code block if the condition is TRUE.

x <- 5

if (x > 0) {
  print("x is positive")
}

b. `if-else` statement:

Adds an alternative action if the initial if condition is FALSE.

if (x > 0) {
  print("x is positive")
} else {
  print("x is non-positive")
}

c. `if-else if-else` statement:

Allows checking multiple conditions sequentially.

if (x > 0) {
  print("x is positive")
} else if (x < 0) {
  print("x is negative")
} else {
  print("x is zero")
}

2. Switch Statement

The switch statement is used to execute one block of code from multiple conditions:

y <- "b"

result <- switch(y,
  a = "You chose A",
  b = "You chose B",
  c = "You chose C",
  "Unknown choice"
)
print(result)

3. Loops

a. `for` loop:

Used for iterating over a sequence (vector, list).

for (i in 1:5) {
  print(i)
}

b. `while` loop:

Keeps running as long as the condition is TRUE.

count <- 1

while (count <= 5) {
  print(count)
  count <- count + 1
}

c. `repeat` loop:

An infinite loop that only breaks when a break statement is encountered.

count <- 1

repeat {
  print(count)
  if (count >= 5) {
    break
  }
  count <- count + 1
}

4. Controlling Loop Execution

a. `next`:

Skips the current iteration and proceeds to the next.

for (i in 1:5) {
  if (i == 3) {
    next
  }
  print(i)
}

b. `break`:

Exits the loop immediately.

for (i in 1:5) {
  if (i == 4) {
    break
  }
  print(i)
}

Summary:

Control statements in R, such as conditional statements (if-else) and loops (for, while, and repeat), offer flexibility in code execution based on specified conditions. By understanding and using these constructs effectively, you can create dynamic and adaptable R scripts.

If-Else Statements in R:

Use if-else statements for conditional execution.

# If-else statements in R
x <- 10
if (x > 0) {
  print("Positive")
} else {
  print("Non-positive")
}

Switch Statement in R:

Implement switch statements for multiple conditions.

# Switch statement in R
day <- "Monday"
message <- switch(day,
                  "Monday" = "Start of the week",
                  "Friday" = "End of the week",
                  "Default message")
print(message)

For Loop in R:

Use for loops for iterative tasks.

# For loop in R
for (i in 1:5) {
  print(paste("Iteration", i))
}

While Loop in R:

Implement while loops for repetitive tasks.

# While loop in R
i <- 1
while (i <= 5) {
  print(paste("Iteration", i))
  i <- i + 1
}

Repeat and Break Statements in R:

Utilize repeat and break statements for indefinite loops.

# Repeat and break statements in R
i <- 1
repeat {
  print(paste("Iteration", i))
  i <- i + 1
  if (i > 5) break
}

Conditional Execution in R Programming:
Execute code conditionally based on logical conditions.
```
# Conditional execution in R programming
x <- 10
if (x > 0) {
  print("Positive")
}
```

Nested Control Statements in R:

Nest control statements for complex logic.

# Nested control statements in R
for (i in 1:3) {
  for (j in 1:3) {
    print(paste("Nested Iteration", i, j))
  }
}

Control Flow in R:

Manage control flow using a combination of statements.

# Control flow in R
x <- 10
if (x > 0) {
  print("Positive")
} else {
  print("Non-positive")
}

Error Handling Within Control Statements in R:

Handle errors within control statements using tryCatch().

# Error handling within control statements in R
tryCatch({
  x <- 1 / 0
  print(x)
}, error = function(e) {
  print(paste("Error:", e$message))
})

Control Statements in R

1. Conditional Execution

a. if statement:

b. if-else statement:

c. if-else if-else statement: