R: Filtering joins for 'SpatVector' objects

filter-joins.SpatVector {tidyterra}

R Documentation

Filtering joins for `SpatVector` objects

Description

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

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

See dplyr::semi_join() for details.

Usage

## S3 method for class 'SpatVector'
semi_join(x, y, by = NULL, copy = FALSE, ...)

## S3 method for class 'SpatVector'
anti_join(x, y, by = NULL, copy = FALSE, ...)

Arguments

`x`	A `SpatVector` created with `terra::vect()`.
`y`	A data frame or other object coercible to a data frame. If a `SpatVector` of `sf` object is provided it would return an error (see `terra::intersect()` for performing spatial joins).
`by`	A join specification created with `join_by()`, or a character vector of variables to join by. If `NULL`, the default, `⁠*_join()⁠` will perform a natural join, using all variables in common across `x` and `y`. A message lists the variables so that you can check they're correct; suppress the message by supplying `by` explicitly. To join on different variables between `x` and `y`, use a `join_by()` specification. For example, `join_by(a == b)` will match `x$a` to `y$b`. To join by multiple variables, use a `join_by()` specification with multiple expressions. For example, `join_by(a == b, c == d)` will match `x$a` to `y$b` and `x$c` to `y$d`. If the column names are the same between `x` and `y`, you can shorten this by listing only the variable names, like `join_by(a, c)`. `join_by()` can also be used to perform inequality, rolling, and overlap joins. See the documentation at ?join_by for details on these types of joins. For simple equality joins, you can alternatively specify a character vector of variable names to join by. For example, `by = c("a", "b")` joins `x$a` to `y$a` and `x$b` to `y$b`. If variable names differ between `x` and `y`, use a named character vector like `by = c("x_a" = "y_a", "x_b" = "y_b")`. To perform a cross-join, generating all combinations of `x` and `y`, see `cross_join()`.
`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.
`...`	Other parameters passed onto methods.

Value

A SpatVector object.

terra equivalent

terra::merge()

Methods

Implementation of the generic dplyr::semi_join() family

`SpatVector`

The geometry column has a sticky behavior. This means that the result would have always the geometry of x for the records that matches the join conditions.

Examples

library(terra)
library(ggplot2)

# Vector
v <- terra::vect(system.file("extdata/cyl.gpkg", package = "tidyterra"))

# A data frame
df <- data.frame(
  cpro = sprintf("%02d", 1:10),
  x = runif(10),
  y = runif(10),
  letter = rep_len(LETTERS[1:3], length.out = 10)
)

v

# Semi join
semi <- v %>% semi_join(df)

semi

autoplot(semi, aes(fill = iso2)) + ggtitle("Semi Join")


# Anti join

anti <- v %>% anti_join(df)

anti

autoplot(anti, aes(fill = iso2)) + ggtitle("Anti Join")

[Package tidyterra version 0.6.1 Index]

Filtering joins for SpatVector objects