instance method

Hash#select

() { (K, V) -> ::boolish } -> ::Hash[K, V]

() -> ::Enumerator[[ K, V ], ::Hash[K, V]]

select {|key, value| ... } → new_hash

select → new_enumerator

static VALUE
rb_hash_select(VALUE hash)
{
    VALUE result;

    RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    result = hash_dup_with_compare_by_id(hash);
    if (!RHASH_EMPTY_P(hash)) {
        rb_hash_foreach(result, keep_if_i, result);
        compact_after_delete(result);
    }
    return result;
}

With a block given, calls the block with each entry’s key and value; returns a new hash whose entries are those for which the block returns a truthy value:

Example

h = {foo: 0, bar: 1, baz: 2}
h.select {|key, value| value < 2 } # => {foo: 0, bar: 1}

With no block given, returns a new Enumerator.

Related: see Methods for Deleting.

See also #select! #replace #reject! #shift also in 4.1 · 3.4 · 3.3 · 3.2 · 3.1 · 3.0

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