Filter objects by class

Based on https://stackoverflow.com/a/5158978/1380598.

classFilter(x, include, exclude, envir)

# S4 method for class 'character,character,character,environment'
classFilter(x, include, exclude, envir)

# S4 method for class 'character,character,character,missing'
classFilter(x, include, exclude)

# S4 method for class 'character,character,missing,environment'
classFilter(x, include, envir)

# S4 method for class 'character,character,missing,missing'
classFilter(x, include)

Arguments

x

Character vector of object names to filter, possibly from ls.

include

Class(es) to include, as a character vector.

exclude

Optional class(es) to exclude, as a character vector.

envir

The environment ins which to search for objects. Default is the calling environment.

Value

Vector of object names matching the class filter.

Note

inherits() is used internally to check the object class, which can, in some cases, return results inconsistent with is. See https://stackoverflow.com/a/27923346/1380598. These (known) cases are checked manually and corrected.

Author

Alex Chubaty

Examples

## from local (e.g., function) environment
local({
  e <- environment()
  a <- list(1:10)     # class `list`
  b <- letters        # class `character`
  d <- stats::runif(10)      # class `numeric`
  f <- sample(1L:10L) # class `numeric`, `integer`
  g <- lm( jitter(d) ~ d ) # class `lm`
  h <- glm( jitter(d) ~ d ) # class `lm`, `glm`
  classFilter(ls(), include=c("character", "list"), envir = e)
  classFilter(ls(), include = "numeric", envir = e)
  classFilter(ls(), include = "numeric", exclude = "integer", envir = e)
  classFilter(ls(), include = "lm", envir = e)
  classFilter(ls(), include = "lm", exclude = "glm", envir = e)
  rm(a, b, d, e, f, g, h)
})

## from another environment (can be omitted if .GlobalEnv)
e = new.env(parent = emptyenv())
e$a <- list(1:10)     # class `list`
e$b <- letters        # class `character`
e$d <- stats::runif(10)      # class `numeric`
e$f <- sample(1L:10L) # class `numeric`, `integer`
e$g <- lm( jitter(e$d) ~ e$d ) # class `lm`
e$h <- glm( jitter(e$d) ~ e$d ) # class `lm`, `glm`
classFilter(ls(e), include=c("character", "list"), envir = e)
#> [1] "a" "b"
classFilter(ls(e), include = "numeric", envir = e)
#> [1] "d" "f"
classFilter(ls(e), include = "numeric", exclude = "integer", envir = e)
#> [1] "d"
classFilter(ls(e), include = "lm", envir = e)
#> [1] "g" "h"
classFilter(ls(e), include = "lm", exclude = "glm", envir = e)
#> [1] "g"
rm(a, b, d, f, g, h, envir = e)
rm(e)