In R, you can add an index column to a data frame using the row.names() function. This function takes the row numbers of the data frame as an argument and assigns them as the new index column. You can then use the index column to reference individual rows in the data frame. Additionally, you can set the start and increment values for the index column to customize the values.
Suppose you have the following data frame:
data <- data.frame(team = c('Spurs', 'Lakers', 'Pistons', 'Mavs'),
avg_points = c(102, 104, 96, 97))
data
# team avg_points
#1 Spurs 102
#2 Lakers 104
#3 Pistons 96
#4 Mavs 97 In order to add an index column to give each row in this data frame a unique numeric ID, you can use the following code:
#add index column to data frame
data$index <- 1:nrow(data)
data
# team avg_points index
#1 Spurs 102 1
#2 Lakers 104 2
#3 Pistons 96 3
#4 Mavs 97 4
Another way to add a unique ID to each row in the data frame is by using the tibble::rowid_to_column function from the tidyverse package:
#load tidyverse package library(tidyverse) #create data frame data <- data.frame(team = c('Spurs', 'Lakers', 'Pistons', 'Mavs'), avg_points = c(102, 104, 96, 97)) #add index column to data frame data <- tibble::rowid_to_column(data, "index") data # index team avg_points #1 1 Spurs 102 #2 2 Lakers 104 #3 3 Pistons 96 #4 4 Mavs 97
Notice that both techniques produce the same result: a new column that gives each row in the data frame a unique ID.