Row and column indexing in R Programming - Mini Project: Build & Apply

Row and column indexing

📖 Scenario: You work in a small shop and keep track of daily sales in a table. You want to learn how to find specific sales data by looking at rows and columns.

🎯 Goal: Learn how to select specific rows and columns from a data frame in R using row and column indexing.

📋 What You'll Learn

Create a data frame called sales with exact values

Create a variable called day_index to select a specific row

Use row and column indexing to select the sales amount for that day

Print the selected sales amount

💡 Why This Matters

🌍 Real World

Selecting specific rows and columns from tables is common when working with sales data, customer data, or any spreadsheet-like information.

💼 Career

Data analysts and scientists often need to extract specific data points from large tables using row and column indexing.

1

Create the sales data frame

Create a data frame called sales with these exact columns and rows:
Day: "Monday", "Tuesday", "Wednesday"
Sales: 150, 200, 175

R Programming

# Create the sales data frame with Day and Sales columns
# Your code here

Need a hint?

Use data.frame() with named vectors for columns.

2

Set the day index

Create a variable called day_index and set it to 2 to select the second row (Tuesday).

R Programming

sales <- data.frame(Day = c("Monday", "Tuesday", "Wednesday"), Sales = c(150, 200, 175))
# Create day_index variable and set it to 2
# Your code here

Need a hint?

Just assign the number 2 to day_index.

3

Select the sales amount for the day

Use row and column indexing with sales and day_index to select the sales amount for that day. Store it in a variable called selected_sales. Use sales[day_index, 2] to get the sales column value.

R Programming

sales <- data.frame(Day = c("Monday", "Tuesday", "Wednesday"), Sales = c(150, 200, 175))
day_index <- 2
# Select the sales amount for the day using row and column indexing
# Your code here

Need a hint?

Use sales[row, column] format to get the value.

4

Print the selected sales amount

Print the value stored in selected_sales using print().

R Programming

sales <- data.frame(Day = c("Monday", "Tuesday", "Wednesday"), Sales = c(150, 200, 175))
day_index <- 2
selected_sales <- sales[day_index, 2]
# Print the selected sales amount
# Your code here

Need a hint?

Use print(selected_sales) to show the value.