instance method

Hash#update

(*::Hash[K, V] other_hashes) -> self

(*::Hash[K, V] other_hashes) { (K key, V oldval, V newval) -> V } -> self

update(*other_hashes) → self

update(*other_hashes) { |key, old_value, new_value| ... } → self

static VALUE
rb_hash_update(int argc, VALUE *argv, VALUE self)
{
    struct update_call_args args = {
        .hash = self,
        .argv = argv,
        .argc = argc,
        .block_given = rb_block_given_p(),
        .iterating = false,
    };
    VALUE arg = (VALUE)&args;

    rb_hash_modify(self);
    return rb_ensure(rb_hash_update_call, arg, rb_hash_update_ensure, arg);
}

Updates values and/or adds entries to self; returns self.

Each argument other_hash in other_hashes must be a hash.

With no block given, for each successive entry key/new_value in each successive other_hash:

If key is in self, sets self[key] = new_value, whose position is unchanged:

Example

h0 = {foo: 0, bar: 1, baz: 2}
h1 = {bar: 3, foo: -1}
h0.update(h1) # => {foo: -1, bar: 3, baz: 2}

If key is not in self, adds the entry at the end of self:

Example

h = {foo: 0, bar: 1, baz: 2}
h.update({bam: 3, bah: 4}) # => {foo: 0, bar: 1, baz: 2, bam: 3, bah: 4}

With a block given, for each successive entry key/new_value in each successive other_hash:

If key is in self, fetches old_value from self[key], calls the block with key, old_value, and new_value, and sets self[key] = new_value, whose position is unchanged :

Example

season = {AB: 75, H: 20, HR: 3, SO: 17, W: 11, HBP: 3}
today = {AB: 3, H: 1, W: 1}
yesterday = {AB: 4, H: 2, HR: 1}
season.update(yesterday, today) {|key, old_value, new_value| old_value + new_value }
# => {AB: 82, H: 23, HR: 4, SO: 17, W: 12, HBP: 3}

If key is not in self, adds the entry at the end of self:

Example

h = {foo: 0, bar: 1, baz: 2}
h.update({bat: 3}) { fail 'Cannot happen' }
# => {foo: 0, bar: 1, baz: 2, bat: 3}

Related: see Methods for Assigning.

See also #transform_values! #value? #transform_values #values also in 4.1 · 3.4 · 3.3 · 3.2 · 3.1 · 3.0

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