R style accesors for the
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
[[ 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.
\$ 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.
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
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