left_join: Warns for "unexpected" behavior of 'left_join'

View source: R/left_join.R

left_joinR Documentation

Warns for "unexpected" behavior of left_join

Description

This code is purposefully intended to hide dplyr's left_join with a wrapper for the same function, but with a warning if the number of rows of the resulting table is greater than the input's. I generally forget about this behavior, so I'm just doing this to help myself remember.

The parameter descriptions are the same as left_join.

Usage

left_join(x, y, by = NULL, copy = FALSE, suffix = c(".x", ".y"), ...)

Arguments

x, y

tbls 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).

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.

copy

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.

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.

...

other parameters passed onto methods, for instance, na_matches to control how NA values are matched. See join.tbl_df for more.


burchill/zplyr documentation built on Feb. 2, 2023, 11:01 a.m.