These are generic functions that dispatch to individual tbl methods - see the
method documentation for details of individual data sources. x and
y should usually be from the same data source, but if copy is
TRUE, y will automatically be copied to the same source as
x - this may be an expensive operation.
inner_join(x, y, by = NULL, copy = FALSE, suffix = c(".x", ".y"), ...)left_join(x, y, by = NULL, copy = FALSE, suffix = c(".x", ".y"), ...)
right_join(x, y, by = NULL, copy = FALSE, suffix = c(".x", ".y"), ...)
full_join(x, y, by = NULL, copy = FALSE, suffix = c(".x", ".y"), ...)
semi_join(x, y, by = NULL, copy = FALSE, ...)
anti_join(x, y, by = NULL, copy = FALSE, ...)
tbls to join
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).
To join by different variables on x and y use a named vector.
For example, by = c("a" = "b") will match x.a to
y.b.
If x and y are not from the same data source,
and copy is TRUE, then y will be copied into the
same src as x. This allows you to join tables across srcs, but
it is a potentially expensive operation so you must opt into it.
If there are non-joined duplicate variables in x and
y, these suffixes will be added to the output to diambiguate them.
other parameters passed onto methods
Currently dplyr supports four join types:
inner_joinreturn all rows from x where there are matching
values in y, and all columns from x and y. If there are multiple matches
between x and y, all combination of the matches are returned.
left_joinreturn all rows from x, and all columns from x
and y. Rows in x with no match in y will have NA values in the new
columns. If there are multiple matches between x and y, all combinations
of the matches are returned.
right_joinreturn all rows from y, and all columns from x
and y. Rows in y with no match in x will have NA values in the new
columns. If there are multiple matches between x and y, all combinations
of the matches are returned.
semi_joinreturn all rows from x where there are matching
values in y, keeping just columns from x.
A semi join differs from an inner join because an inner join will return
one row of x for each matching row of y, where a semi
join will never duplicate rows of x.
anti_joinreturn all rows from x where there are not
matching values in y, keeping just columns from x.
full_joinreturn all rows and all columns from both x and y.
Where there are not matching values, returns NA for the one missing.
Groups are ignored for the purpose of joining, but the result preserves
the grouping of x.