R: Accessor methods for the hash class.

hash-accessors {hash} | R Documentation

## Accessor methods for the hash class.

### Description

R style accesors for the `hash-class`.

### Details

These are the hash accessor methods. They closely follow an R style.

`$` is a look-up operator for a single key. The native `$` method is used. The key is taken as a string literal and is not interpreted.

`[[` is the look-up, extraction operator. It returns the values of a single key.

`[` is a subseting operator. It returns a (sub) hash with the specified keys. All other keys are removed.

### Value

\$ and [[ return the value for the supplied argument. If a key does not match an existing key, then `NULL` is returned with a warning.

[ returns a hash slice, a sub hash with only the defined keys.

### Author(s)

Christopher Brown

### See Also

`hash`, `values`, `.set`, `as.list`

### Examples

      h <- hash()
      h <- hash( letters, 1:26 )

      h$a
      h$a <- "2"
      h$z <- NULL          # Removes 'z' from

      h[['a']]
      h[['a']] <- 23

      h[ letters[1:4] ]    # hash with a,b,c,d
      h[ letters[1:4] ] <- 4:1

[Package hash version 2.2.6 Index]