R: Accessor methods for the hash class.
hash-accessors | 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
Results
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