fastmap
provides a key-value store where the keys are strings and the
values are any R objects. It differs from normal environment that
fastmap avoids memory leak. fastmap2
is a wrapper for fastmap, which provides several generic
functions such that it has similar behaviors to lists or
environments
Usage
fastmap2(missing_default = NULL)
# S3 method for fastmap2
[[(x, name)
# S3 method for fastmap2
$(x, name)
# S3 method for fastmap2
[[(x, name) <- value
# S3 method for fastmap2
$(x, name) <- value
# S3 method for fastmap2
[(x, i, j = NULL, ...)
# S3 method for fastmap2
[(x, i, j = NULL, ...) <- value
# S3 method for fastmap2
names(x)
# S3 method for fastmap2
print(x, ...)
# S3 method for fastmap2
length(x)
# S3 method for fastmap2
as.list(x, recursive = FALSE, sorted = FALSE, ...)Arguments
- missing_default
passed to
fastmap::fastmap- x
a
'fastmap2'object- name
name, or key of the value
- value
any R object
- i, j
vector of names
- ...
passed to other methods
- recursive
whether to recursively apply
as.list- sorted
whether to sort names; default is false
Examples
## --------------------------- Basic Usage --------------------------
map <- fastmap2()
map$a = 1
map$b = 2
print(map)
#> <Map, size=2, keys=[b, a]>
map[c('a', 'b')]
#> $a
#> [1] 1
#>
#> $b
#> [1] 2
#>
# Alternative way
map['a', 'b']
#> $a
#> [1] 1
#>
#> $b
#> [1] 2
#>
map[c('c', 'd')] <- 3:4
# or
map['e', 'f'] <- 5:6
# The order is not guaranteed, unless sort=TRUE
as.list(map)
#> $f
#> [1] 6
#>
#> $e
#> [1] 5
#>
#> $d
#> [1] 4
#>
#> $c
#> [1] 3
#>
#> $b
#> [1] 2
#>
#> $a
#> [1] 1
#>
as.list(map, sort=TRUE)
#> $a
#> [1] 1
#>
#> $b
#> [1] 2
#>
#> $c
#> [1] 3
#>
#> $d
#> [1] 4
#>
#> $e
#> [1] 5
#>
#> $f
#> [1] 6
#>
names(map)
#> [1] "f" "e" "d" "c" "b" "a"
length(map)
#> [1] 6
## ----------------------- NULL value handles -----------------------
map$b <- NULL
names(map) # 'b' still exists!
#> [1] "f" "e" "d" "c" "b" "a"
as.list(map) # 'b' is NULL, but still there
#> $f
#> [1] 6
#>
#> $e
#> [1] 5
#>
#> $d
#> [1] 4
#>
#> $c
#> [1] 3
#>
#> $b
#> NULL
#>
#> $a
#> [1] 1
#>
# to remove 'b', you have to use `@remove` method
map$`@remove`('b')
## ---------------- Native fastmap::fastmap methods -----------------
# whether map has 'a'
map$`@has`('a')
#> [1] TRUE
# Remove a name from list
map$`@remove`('a')
# remove all from list
map$`@reset`()
print(map)
#> <Map, size=0, keys=[]>