extract-keys ( seq assoc -- subassoc )
Factor handbook » The language » Collections » Associative mapping operations » Set-theoretic operations on assocs

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Vocabulary
assocs

Inputs

seq	a sequence
assoc	an assoc

Outputs

subassoc

an assoc

Word description
Outputs an new assoc with key/value pairs whose keys match the elements in the input seq.

Examples

USING: prettyprint assocs ; { 1 3 } { { 1 10 } { 2 20 } { 3 30 } } extract-keys .
{ { 1 10 } { 3 30 } }

Definition

USING: kernel ;

IN: assocs

: extract-keys ( seq assoc -- subassoc )
    [ [ dupd at ] curry ] keep map>assoc ;