grep and grepl in R Programming - Mini Project: Build & Apply

Using grep and grepl in R to Find Words in a List

📖 Scenario: Imagine you have a list of fruit names and you want to find which fruits contain the word "apple".

🎯 Goal: You will learn how to use grep and grepl functions in R to search for words inside a list of strings.

📋 What You'll Learn

Create a character vector with fruit names

Create a search word variable

Use grep to find positions of fruits containing the search word

Use grepl to get a logical vector showing which fruits contain the search word

Print the results

💡 Why This Matters

🌍 Real World

Searching text data for specific words or patterns is common in data analysis, such as finding keywords in customer feedback or filtering product names.

💼 Career

Knowing how to use <code>grep</code> and <code>grepl</code> helps in data cleaning, text mining, and preparing data for reports or machine learning.

1

Create a vector of fruit names

Create a character vector called fruits with these exact values: "apple", "banana", "pineapple", "orange", "grape"

R Programming

# Create the fruits vector with the given fruit names
# Your code here

Need a hint?

Use the c() function to combine the fruit names into a vector.

2

Create a search word variable

Create a variable called search_word and set it to the string "apple"

R Programming

fruits <- c("apple", "banana", "pineapple", "orange", "grape")
# Create the search_word variable with the value "apple"
# Your code here

Need a hint?

Just assign the string "apple" to the variable search_word.

3

Use grep and grepl to find fruits containing the search word

Use grep with search_word and fruits to find the positions of fruits containing "apple" and store it in positions. Then use grepl with the same inputs to get a logical vector and store it in matches.

R Programming

fruits <- c("apple", "banana", "pineapple", "orange", "grape")
search_word <- "apple"
# Use grep to find positions of fruits containing search_word
# Use grepl to get logical vector of matches
# Your code here

Need a hint?

Remember grep returns positions (numbers), and grepl returns TRUE or FALSE for each element.

4

Print the results

Print the positions vector and then print the matches vector to show which fruits contain the word "apple".

R Programming

fruits <- c("apple", "banana", "pineapple", "orange", "grape")
search_word <- "apple"
positions <- grep(search_word, fruits)
matches <- grepl(search_word, fruits)
# Print positions and matches
# Your code here

Need a hint?

Use print() to show the vectors.