How To Subset A Data Frame In R (4 Examples) - - Statology

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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 <- data.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 <- names(df) %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 < 80) team points assists 1 A 77 19 5 C 99 32 6 C 92 39 7 C 97 14

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

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