Create the map m containing all the elements e of the list a, using as key the field e.id.
m = dict((x.id, x) for x in a)
m = {e.id:e for e in a}
final m = { for (final e in a) e.id: e, };
m := make(map[K]V, len(a)) for _, e := range a { m[e.id] = e }
let m = new Map(a.map(e => [e.id, e]))
import java.util.HashMap; import java.util.Map;
Map<Integer, E> m = new HashMap<>(); a.forEach(e -> m.put(e.id, e));
import java.util.Map;
Map<Integer, E> m = a.stream() .collect(toMap(e -> e.id, e -> e));
Map<Integer, E> m = new HashMap<>(); for (E e : a) m.put(e.id, e);
local m={} for _,e in ipairs(a) do m[e.id]=e end
foreach my $e (@a) { $m{$e->id) = $e; }
m = a.group_by(&:id)
use std::collections::HashMap;
let mut m = HashMap::new(); for e in a { m.entry(e.id).or_insert_with(Vec::new).push(e); }
No security, no password. Other people might choose the same nickname.