You can use the following basic syntax to subset a data frame in R:
df[rows, columns]
The following examples show how to use this syntax in practice with the following data frame:
#create data frame df frame(team=c('A', 'A', 'B', 'B', 'C', 'C', 'C'), points=c(77, 81, 89, 83, 99, 92, 97), assists=c(19, 22, 29, 15, 32, 39, 14)) #view data frame df team points assists 1 A 77 19 2 A 81 22 3 B 89 29 4 B 83 15 5 C 99 32 6 C 92 39 7 C 97 14
Example 1: Subset Data Frame by Selecting Columns
The following code shows how to subset a data frame by column names:
#select all rows for columns 'team' and 'assists'
df[ , c('team', 'assists')]
team assists
1 A 19
2 A 22
3 B 29
4 B 15
5 C 32
6 C 39
7 C 14
We can also subset a data frame by column index values:
#select all rows for columns 1 and 3
df[ , c(1, 3)]
team assists
1 A 19
2 A 22
3 B 29
4 B 15
5 C 32
6 C 39
7 C 14
Example 2: Subset Data Frame by Excluding Columns
The following code shows how to subset a data frame by excluding specific column names:
#define columns to exclude cols %in% c('points') #exclude points column df[!cols] team assists 1 A 19 2 A 22 3 B 29 4 B 15 5 C 32 6 C 39 7 C 14
We can also exclude columns using index values
#exclude column 2
df[ , c(-2)]
team assists
1 A 19
2 A 22
3 B 29
4 B 15
5 C 32
6 C 39
7 C 14
Example 3: Subset Data Frame by Selecting Rows
The following code shows how to subset a data frame by specific rows:
#select rows 1, 5, and 7 df[c(1, 5, 7), ] team points assists 1 A 77 19 5 C 99 32 7 C 97 14
We can also subset a data frame by selecting a range of rows:
#select rows 1 through 5 df[1:5, ] team points assists 1 A 77 19 2 A 81 22 3 B 89 29 4 B 83 15 5 C 99 32
Example 4: Subset Data Frame Based on Conditions
The following code shows how to use the subset() function to select rows and columns that meet certain conditions:
#select rows where points is greater than 90
subset(df, points > 90)
team points assists
5 C 99 32
6 C 92 39
7 C 97 14
We can also use the | (“or”) operator to select rows that meet one of several conditions:
#select rows where points is greater than 90 or less than 80
subset(df, points > 90 | points
We can also use the & (“and”) operator to select rows that meet multiple conditions:
#select rows where points is greater than 90 and assists is greater than 30
subset(df, points > 90 & assists > 30)
team points assists
5 C 99 32
6 C 92 39
We can also use the select argument to only select certain columns based on a condition:
#select rows where points is greater than 90 and only show 'team' column
subset(df, points > 90, select=c('team'))
team
5 C
6 C
7 C
Additional Resources
How to Remove Rows from Data Frame in R Based on Condition
How to Replace Values in Data Frame in R
How to Drop Columns from Data Frame in R