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Filtering joins filter rows from x based on the presence or absence of matches in y:

Source: R/joins_filtering.R
filter_joins.Rd

  • semi_join() return all rows from x with a match in y.

  • anti_join() return all rows from x without a match in y.

Usage

anti_join(x, y, by = NULL)

semi_join(x, y, by = NULL)

Arguments

x, y

The data.frames to join.

by

A character vector of variables to join by. If NULL, the default, *_join() will do a natural join, using all variables with common names across the two tables. A message lists the variables so that you can check they're right (to suppress the message, simply explicitly list the variables that you want to join).

Examples

table1 <- data.frame(
  pupil = rep(1:3, each = 2),
  test = rep(c("A", "B"), 3),
  score = c(60, 70, 65, 80, 85, 70),
  stringsAsFactors = FALSE
)
table2 <- table1[c(1, 3, 4), ]

table1 %>% anti_join(table2, by = c("pupil", "test"))
#>   pupil test score
#> 1     1    B    70
#> 2     3    A    85
#> 3     3    B    70
table1 %>% semi_join(table2, by = c("pupil", "test"))
#>   pupil test score
#> 1     1    A    60
#> 2     2    A    65
#> 3     2    B    80