Creating implementation for idiom 335 : List to map

Idiom

# 335 List to map

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Create the map m containing all the elements e of the list a, using as key the field e.id.

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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
}

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));

import java.util.HashMap;
import java.util.Map;

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 = {e.id:e for e in a}

f = lambda x: (x.id, x)
m = dict(map(f, a))

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);
}