instance method

Hash#each_key

() { (K arg0) -> untyped } -> ::Hash[K, V]

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

each_key {|key| ... } → self

each_key → new_enumerator

static VALUE
rb_hash_each_key(VALUE hash)
{
    RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    rb_hash_foreach(hash, each_key_i, 0);
    return hash;
}

With a block given, calls the block with each key; returns self:

Example

h = {foo: 0, bar: 1, baz: 2}
h.each_key {|key| puts key }  # => {foo: 0, bar: 1, baz: 2}

Output:

Example

foo
bar
baz

With no block given, returns a new Enumerator.

Related: see Methods for Iterating.

See also #each #each_pair #dig #each_value also in 4.1 · 3.4 · 3.3 · 3.2 · 3.1 · 3.0

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