instance method

Hash#<

[A, B] (::Hash[A, B]) -> bool

self < other → true or false

static VALUE
rb_hash_lt(VALUE hash, VALUE other)
{
    other = to_hash(other);
    if (RHASH_SIZE(hash) >= RHASH_SIZE(other)) return Qfalse;
    return hash_le(hash, other);
}

Returns whether the entries of self are a proper subset of the entries of other:

Example

h = {foo: 0, bar: 1}
h < {foo: 0, bar: 1, baz: 2} # => true   # Proper subset.
h < {baz: 2, bar: 1, foo: 0} # => true   # Order may differ.
h < h                        # => false  # Not a proper subset.
h < {bar: 1, foo: 0}         # => false  # Not a proper subset.
h < {foo: 0, bar: 1, baz: 2} # => false  # Different key.
h < {foo: 0, bar: 1, baz: 2} # => false  # Different value.

See Hash Inclusion.

Raises TypeError if other_hash is not a hash and cannot be converted to a hash.

Related: see Methods for Comparing.

See also #<= .try_convert .ruby2_keywords_hash? #== also in 4.1 · 3.4 · 3.3 · 3.2 · 3.1 · 3.0

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