hash/associative array/dictionary data structure for the R language

Preferred constructor for the hash-class.

hash(...)

  is.hash(x)

  # S3 method for class 'hash'
as.list(x, all.names = FALSE, ...  )

Arguments

x

A hash object.

all.names

a logical indicating whether to copy all values or (default) only those whose names do not begin with a dot

...

Additional arguments passed to the function

Details

hash returns a hash object. Key-value pairs may be specified via the ... argument as explicity arguments keys and values, as named key-value pairs, as a named vector or as implicit key, value vectors. See examples below for each type.

Keys must be a valid R name, must be a character vector and must not be the empty string, "". Values are restricted to any valid R objects.

See .set for further details and how key-value vectors of unequal length are interpretted.

Hashes may be accessed via the standard R accessors [, [[ and \$. See hash-accessors for details.

is.hash returns a boolean value indicating if the argument is a hash object.

as.list.hash coerces the hash to a list.

Value

For hash, an object of class hash.

Author

Christopher Brown

See also

.set, hash-accessors

Examples

  hash()
#> <hash> containing 0 key-value pair(s).
#>   NA : NULL

  hash( key=letters, values=1:26 )
#> <hash> containing 2 key-value pair(s).
#>   key : a b c d e f g h i j k l m n o p q r s t u v w x y z
#>   values :  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
  
  hash( 1:3, lapply(1:3, seq, 1 ))
#> <hash> containing 3 key-value pair(s).
#>   1 : 1
#>   2 : 2 1
#>   3 : 3 2 1
  
  hash( a=1, b=2, c=3 )
#> <hash> containing 3 key-value pair(s).
#>   a : 1
#>   b : 2
#>   c : 3
  hash( c(a=1, b=2, c=3) ) 
#> <hash> containing 3 key-value pair(s).
#>   a : 1
#>   b : 2
#>   c : 3
  hash( list(a=1,b=2,c=3) )
#> <hash> containing 3 key-value pair(s).
#>   a : 1
#>   b : 2
#>   c : 3

  hash( c("foo","bar","baz"), 1:3 )
#> <hash> containing 3 key-value pair(s).
#>   bar : 2
#>   baz : 3
#>   foo : 1
  hash( c("foo","bar","baz"),  lapply(1:3, seq, 1 ) )
#> <hash> containing 3 key-value pair(s).
#>   bar : 2 1
#>   baz : 3 2 1
#>   foo : 1
  hash( letters, 1:26 )
#> <hash> containing 26 key-value pair(s).
#>   a : 1
#>   b : 2
#>   c : 3
#>   d : 4
#>   e : 5
#>   f : 6
#>   g : 7
#>   h : 8
#>   i : 9
#>   j : 10
#>   k : 11
#>   l : 12
#>   m : 13
#>   n : 14
#>   o : 15
#>   p : 16
#>   q : 17
#>   r : 18
#>   s : 19
#>   t : 20
#>   u : 21
#>   v : 22
#>   w : 23
#>   x : 24
#>   y : 25
#>   z : 26

  h <- hash( letters, 1:26 )
  h$a
#> [1] 1
  h$b
#> [1] 2
  h[[ "a" ]]
#> [1] 1
  h[ letters[1:3] ]
#> <hash> containing 3 key-value pair(s).
#>   a : 1
#>   b : 2
#>   c : 3

  h$a<-100
  # h[['a']]<-letters

  is.hash(h)
#> [1] TRUE
  as.list(h)
#> $i
#> [1] 9
#> 
#> $j
#> [1] 10
#> 
#> $k
#> [1] 11
#> 
#> $l
#> [1] 12
#> 
#> $m
#> [1] 13
#> 
#> $n
#> [1] 14
#> 
#> $o
#> [1] 15
#> 
#> $p
#> [1] 16
#> 
#> $q
#> [1] 17
#> 
#> $r
#> [1] 18
#> 
#> $s
#> [1] 19
#> 
#> $t
#> [1] 20
#> 
#> $u
#> [1] 21
#> 
#> $v
#> [1] 22
#> 
#> $w
#> [1] 23
#> 
#> $x
#> [1] 24
#> 
#> $y
#> [1] 25
#> 
#> $z
#> [1] 26
#> 
#> $a
#> [1] 100
#> 
#> $b
#> [1] 2
#> 
#> $c
#> [1] 3
#> 
#> $d
#> [1] 4
#> 
#> $e
#> [1] 5
#> 
#> $f
#> [1] 6
#> 
#> $g
#> [1] 7
#> 
#> $h
#> [1] 8
#> 

  clear(h)
  rm(h)