filter! ( ... seq quot: ( ... elt -- ... ? ) -- ... seq )
Factor handbook » The language » Collections » Sequence operations » Destructive sequence operations

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Vocabulary
sequences

Inputs

seq	a resizable mutable sequence
quot	a quotation with stack effect ( ... elt -- ... ? )

Outputs

seq	a resizable mutable sequence

Word description
Applies the quotation to each element in turn, and removes elements for which the quotation outputs a false value.

Notes
The sequence seq MUST be growable. See Resizable sequence implementation.

Side effects
Modifies seq

Examples
Remove the odd numbers

USING: kernel math prettyprint sequences ; V{ 1 2 3 4 5 6 7 8 9 0 } [ odd? not ] filter! .
V{ 2 4 6 8 0 }

See also
filter, filter-as, reject, reject-as, reject!, sift, harvest

Definition

USING: kernel sequences.private ;

IN: sequences

: filter! ( ... seq quot: ( ... elt -- ... ? ) -- ... seq )
    [ 0 0 ] 2dip filter-from! ; inline