You can use one of the following methods to select rows by condition in R:
Method 1: Select Rows Based on One Condition
df[df$var1 == 'value', ]
Method 2: Select Rows Based on Multiple Conditions
df[df$var1 == 'value1' & df$var2 > value2, ]
Method 3: Select Rows Based on Value in List
df[df$var1 %in% c('value1', 'value2', 'value3'), ]
The following examples show how to use each method with the following data frame in R:
#create data frame df <- data.frame(points=c(1, 2, 4, 3, 4, 8), assists=c(6, 6, 7, 8, 8, 9), team=c('A', 'A', 'A', 'B', 'C', 'C')) #view data frame df points assists team 1 1 6 A 2 2 6 A 3 4 7 A 4 3 8 B 5 4 8 C 6 8 9 C
Method 1: Select Rows Based on One Condition
The following code shows how to select rows based on one condition in R:
#select rows where team is equal to 'A' df[df$team == 'A', ] points assists team 1 1 6 A 2 2 6 A 3 4 7 A
Notice that only the rows where the team is equal to ‘A’ are selected.
We can also use != to select rows that are not equal to some value:
#select rows where team is not equal to 'A' df[df$team != 'A', ] points assists team 4 3 8 B 5 4 8 C 6 8 9 C
Method 2: Select Rows Based on Multiple Conditions
The following code shows how to select rows based on multiple conditions in R:
#select rows where team is equal to 'A' and points is greater than 1 df[df$team == 'A' & df$points > 1, ] points assists team 2 2 6 A 3 4 7 A
Notice that only the rows where the team is equal to ‘A’ and where points is greater than 1 are selected.
Method 3: Select Rows Based on Value in List
The following code shows how to select rows where the value in a certain column belongs to a list of values:
#select rows where team is equal to 'A' or 'C' df[df$team %in% c('A', 'C'), ]
Notice that only the rows where the team is equal to ‘A’ or ‘C’ are selected.
Additional Resources
The following tutorials explain how to perform other common operations in R:
How to Select Rows Where Value Appears in Any Column in R
How to Select Specific Columns in R
How to Select Columns by Index in R
