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R: Sorting Data by Column Names and Values Made Simple

Sorting in R made simple: A beginner’s guide to matching column names and values.

David Techwell
DataFrontiers
Published in
3 min readDec 6, 2023

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Easy Data Sorting in R: A Beginner’s Guide

Hey friends! 🌟 Ever struggled with sorting data in R? Well, you’re not alone. Let’s explore an interesting challenge that often pops up for R newbies and pros alike. It’s all about sorting data based on the last character in column names matching the last character in values of a reference column. Sounds tricky, right? But don’t worry, it’s simpler than it sounds!

Imagine you have a bunch of columns with names ending in numbers, like ‘a1’, ‘b2’, ‘c3’, and so on. And you’ve got this one special column, let’s call it ‘x’, that has values like ‘x1’, ‘x2’, ‘x3’, etc. The goal is to pull values from these columns into a new column, ‘y’, where the last character of ‘x’ matches the last character of the column names. Interesting, huh?

# Sample Data
my_data <- data.frame(a2 = c('apple', 'banana'),
a3 = c('cherry', 'date'),
a4 = c('elderberry', 'fig'),
x = c('x2', 'x3'))

With this setup, how do you go about solving this puzzle? Let’s find out together in the next sections! 😊

Alright, let’s dive into the solution! 😎 The key here is to use R’s awesome libraries, like dplyr and stringr, to make our job easier. We’ll create a function that matches the last characters and pulls the right data into our new column.

library(dplyr)
library(stringr)

# Creating the function
column_matcher <- function(data, ref_column) {
data %>% mutate(y = case_when(
str_sub(ref_column, start = -1) == '2' ~ a2,
str_sub(ref_column, start = -1) == '3' ~ a3,
str_sub(ref_column, start = -1) == '4' ~ a4,
TRUE ~ NA_character_
))
}

# Applying the function
clean_data <- column_matcher(my_data, my_data$x)

With this nifty function, we’re telling R to look at the last character of our reference column ‘x’ and match it with the column that has the same ending. If ‘x’ ends in ‘2’, grab the value from ‘a2’, and so on. It’s like magic, but in R!

Now, let’s see this function in action! 🚀 When we apply column_matcher to our data, it smartly picks the right values based on our rule. Here's the cool result:

# Displaying the result
print(clean_data)

# Expected Output
# a2 a3 a4 x y
# 1 apple cherry NA x2 apple
# 2 banana date NA x3 date

And there you have it! 🌈 A super easy way to sort and match data in R. This method can be super helpful in various data tasks, and the best part? It’s pretty fun to do. So go ahead, give it a try and see how you can apply this cool trick in your own projects!

References & FAQs

That’s a wrap on sorting data in R using dplyr! To learn more and become an R wizard, check out these awesome resources:

SEO Optimized FAQs

Q: How do I start using dplyr in R for data sorting?

A: To start, install dplyr and explore its basic data manipulation tools like mutate, select, and filter. Check out the official documentation for a step-by-step guide!

Q: Can dplyr work with databases?

A: Yes! dplyr supports databases through the dbplyr package. It’s great for applying dplyr’s tools to database data.

Q: What is tidy evaluation in dplyr?

A: Tidy evaluation is a special type of non-standard evaluation used in dplyr. It helps in programming with dplyr more effectively.

Originally published on HackingWithCode.com.

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David Techwell
DataFrontiers

Tech Enthusiast, Software Engineer, and Passionate Blogger.