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The anti_join function in the dplyr package can be used to find records in one data set that do not match a record in another data set. This is done by joining two data sets on a given variable, and then returning all records from the first data set that did not have a corresponding match in the second data set. This is useful for finding unmatched records between two datasets.
You can use the anti_join() function from the package in R to return all rows in one data frame that do not have matching values in another data frame.
This function uses the following basic syntax:
anti_join(df1, df2, by='col_name')
The following examples show how to use this syntax in practice.
Example 1: Use anti_join() with One Column
Suppose we have the following two data frames in R:
#create data frames df1 <- data.frame(team=c('A', 'B', 'C', 'D', 'E'), points=c(12, 14, 19, 24, 36)) df2 <- data.frame(team=c('A', 'B', 'C', 'F', 'G'), points=c(12, 14, 19, 33, 17))
We can use the anti_join() function to return all rows in the first data frame that do not have a matching team in the second data frame:
library(dplyr) #perform anti join using 'team' column anti_join(df1, df2, by='team') team points 1 D 24 2 E 36
We can see that there are exactly two teams from the first data frame that do not have a matching team name in the second data frame.
Example 2: Use anti_join() with Multiple Columns
Suppose we have the following two data frames in R:
#create data frames df1 <- data.frame(team=c('A', 'A', 'A', 'B', 'B', 'B'), position=c('G', 'G', 'F', 'G', 'F', 'C'), points=c(12, 14, 19, 24, 36, 41)) df2 <- data.frame(team=c('A', 'A', 'A', 'B', 'B', 'B'), position=c('G', 'G', 'C', 'G', 'F', 'F'), points=c(12, 14, 19, 33, 17, 22))
We can use the anti_join() function to return all rows in the first data frame that do not have a matching team and position in the second data frame:
library(dplyr) #perform anti join using 'team' and 'position' columns anti_join(df1, df2, by=c('team', 'position')) team position points 1 A F 19 2 B C 41
We can see that there are exactly two records from the first data frame that do not have a matching team name and position in the second data frame.