Pop First Element for One Key

Removes and returns the first element whose key equals key.

Usage

pop_key(x, key)

Arguments

x

An ordered_sequence.

key

Query key.

Value

A list with fields:

• value: removed element, or NULL on miss.

• key: removed key, or NULL on miss.

• remaining: ordered sequence after removal.

Details

For duplicate keys, the first element in stable sequence order is removed.

Examples

x <- ordered_sequence("a", "b", "c", keys = c(1, 2, 2))
out <- pop_key(x, 2)
out$value
#> [1] "b"
out$remaining
#> Unnamed ordered_sequence with 2 elements.
#> 
#> Elements (by key order):
#> 
#> [[1]] (key 1)
#> [1] "a"
#> 
#> [[2]] (key 2)
#> [1] "c"
#> 
pop_key(x, 10)
#> $value
#> NULL
#> 
#> $key
#> NULL
#> 
#> $remaining
#> Unnamed ordered_sequence with 3 elements.
#> 
#> Elements (by key order):
#> 
#> [[1]] (key 1)
#> [1] "a"
#> 
#> [[2]] (key 2)
#> [1] "b"
#> 
#> [[3]] (key 2)
#> [1] "c"
#> 
#>