instance method

Hash#invert

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

invert → new_hash

static VALUE
rb_hash_invert(VALUE hash)
{
    VALUE h = rb_hash_new_with_size(RHASH_SIZE(hash));

    rb_hash_foreach(hash, rb_hash_invert_i, h);
    return h;
}

Returns a new hash with each key-value pair inverted:

Example

h = {foo: 0, bar: 1, baz: 2}
h1 = h.invert
h1 # => {0=>:foo, 1=>:bar, 2=>:baz}

Overwrites any repeated new keys (see Entry Order):

Example

h = {foo: 0, bar: 0, baz: 0}
h.invert # => {0=>:baz}

See also #inspect #keep_if #initialize_copy #key also in 4.1 · 3.4 · 3.3 · 3.2 · 3.1 · 3.0

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