The gather() function in R is “used to gather a key-value pair across multiple columns”.
Syntax
gather(data, key value)Parameters
- data: It is the name of the data frame.
- key: It is the name of the key column to create.
- value: It is the name of the value column to create
Example 1: Gather Values From Two Columns
library(tidyr)
data_wide <- data.frame(
id = c(1, 2, 3),
variable1 = c(5, 6, 7),
variable2 = c(10, 11, 12)
)
# Convert the data frame from wide to long format
data_long <- gather(data_wide, key = "variable", value = "value", -id)
# Print the long data frame
print(data_long)
Output
id variable value
1 1 variable1 5
2 2 variable1 6
3 3 variable1 7
4 1 variable2 10
5 2 variable2 11
6 3 variable2 12
Example 2: Gather Values From More than Two Columns
To gather values from more than two columns in R, you can use the “gather()” function from the tidyr package.
library(tidyr)
# create data frame
df <- data.frame(
student = c("A", "B", "C", "D"),
year1 = c(2011, 2012, 2013, 2014),
year2 = c(2015, 2016, 2017, 2018),
year3 = c(2019, 2020, 2021, 2022)
)
# Gather the values from the year1, year2, and year3 columns.
df_gathered <- gather(df, key, value, year1, year2, year3)
# Print the data frame.
print(df_gathered)
Output
As mentioned earlier, the gather() function has been superseded by the pivot_longer() function in the tidyr package.
It is recommended to use pivot_longer() for new projects, as it offers a more consistent and flexible interface for reshaping data.
That’s it.
Krunal Lathiya is a seasoned Computer Science expert with over eight years in the tech industry. He boasts deep knowledge in Data Science and Machine Learning. Versed in Python, JavaScript, PHP, R, and Golang. Skilled in frameworks like Angular and React and platforms such as Node.js. His expertise spans both front-end and back-end development. His proficiency in the Python language stands as a testament to his versatility and commitment to the craft.