instance method

Hash#select!

() { (K, V) -> ::boolish } -> self?

() -> ::Enumerator[[ K, V ], self?]

select! {|key, value| ... } → self or nil

select! → new_enumerator

static VALUE
rb_hash_select_bang(VALUE hash)
{
    st_index_t n;

    RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    rb_hash_modify_check(hash);
    n = RHASH_SIZE(hash);
    if (!n) return Qnil;
    rb_hash_foreach(hash, keep_if_i, hash);
    if (n == RHASH_SIZE(hash)) return Qnil;
    return hash;
}

With a block given, calls the block with each entry’s key and value; removes from self each entry for which the block returns false or nil.

Returns self if any entries were removed, nil otherwise:

Example

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

With no block given, returns a new Enumerator.

Related: see Methods for Deleting.

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

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