filterAt$

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Subhajit Sahu edited this page Dec 5, 2022 · 12 revisions

Keep values at given keys.

Alternatives: filterAt, filterAt$.
Similar: map, reduce, filter, filterAt, reject, rejectAt.

function filterAt$(x, ks)
// x:  a map (updated)
// ks: keys

const map = require('extra-map');

var x = new Map([['a', 1], ['b', 2], ['c', 3], ['d', 4], ['e', 5]]);
map.filterAt$(x, ['a', 'c', 'e']);
// → Map(3) { 'a' => 1, 'c' => 3, 'e' => 5 }

x;
// → Map(3) { 'a' => 1, 'c' => 3, 'e' => 5 }

var x = new Map([['a', 1], ['b', 2], ['c', 3], ['d', 4], ['e', 5]]);
map.filterAt$(x, ['b', 'd']);
// → Map(2) { 'b' => 2, 'd' => 4 }

References