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instance method

Set#add?

(A) -> self?

add?(object) → self or nil

static VALUE
set_i_add_p(VALUE set, VALUE item)
{
    rb_check_frozen(set);
    if (set_iterating_p(set)) {
        if (!set_table_lookup(RSET_TABLE(set), (st_data_t)item)) {
            no_new_item();
        }
        return Qnil;
    }
    else {
        return set_insert_wb(set, item) ? Qnil : set;
    }
}

Like add, but returns nil if the given object is already in self:

Example

set = Set[0, 1, 2]
set.add?(:foo)   # => Set[0, 1, 2, :foo]
set.add?(0..9) # => Set[0, 1, 2, :foo, 0..9]
set.add?(2) # => nil

Related: see Methods for Assigning.

See also #add #classify #| #clear also in 4.0 · 3.4 · 3.3 · 3.2 · 3.1 · 3.0

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