dt_left_join | R Documentation |
Do different versions of SQL join operations. See examples.
dt_left_join(x, y, by = NULL, suffix = c(".x", ".y")) dt_right_join(x, y, by = NULL, suffix = c(".x", ".y")) dt_inner_join(x, y, by = NULL, suffix = c(".x", ".y")) dt_full_join(x, y, by = NULL, suffix = c(".x", ".y")) dt_semi_join(x, y, by = NULL) dt_anti_join(x, y, by = NULL)
x |
data.frame or data.table |
y |
data.frame or data.table |
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). To join by different variables on x and y
use a named vector. For example, |
suffix |
If there are non-joined duplicate variables in x and y, these suffixes will be added to the output to disambiguate them. Should be a character vector of length 2. |
data.table
workers = fread(" name company Nick Acme John Ajax Daniela Ajax ") positions = fread(" name position John designer Daniela engineer Cathie manager ") workers %>% dt_inner_join(positions) workers %>% dt_left_join(positions) workers %>% dt_right_join(positions) workers %>% dt_full_join(positions) # filtering joins workers %>% dt_anti_join(positions) workers %>% dt_semi_join(positions) # To suppress the message, supply 'by' argument workers %>% dt_left_join(positions, by = "name") # Use a named 'by' if the join variables have different names positions2 = setNames(positions, c("worker", "position")) # rename first column in 'positions' workers %>% dt_inner_join(positions2, by = c("name" = "worker"))
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