Method: Regexp.union

Defined in:
re.c

.union(*patterns) ⇒ Regexp .union(array_of_patterns) ⇒ Regexp

Returns a new regexp that is the union of the given patterns:

r = Regexp.union(%w[cat dog])      # => /cat|dog/
r.match('cat')      # => #<MatchData "cat">
r.match('dog')      # => #<MatchData "dog">
r.match('cog')      # => nil

For each pattern that is a string, Regexp.new(pattern) is used:

Regexp.union('penzance')             # => /penzance/
Regexp.union('a+b*c')                # => /a\+b\*c/
Regexp.union('skiing', 'sledding')   # => /skiing|sledding/
Regexp.union(['skiing', 'sledding']) # => /skiing|sledding/

For each pattern that is a regexp, it is used as is, including its flags:

Regexp.union(/foo/i, /bar/m, /baz/x)
# => /(?i-mx:foo)|(?m-ix:bar)|(?x-mi:baz)/
Regexp.union([/foo/i, /bar/m, /baz/x])
# => /(?i-mx:foo)|(?m-ix:bar)|(?x-mi:baz)/

With no arguments, returns /(?!)/:

Regexp.union # => /(?!)/

If any regexp pattern contains captures, the behavior is unspecified.

Overloads:



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# File 're.c', line 4387

static VALUE
rb_reg_s_union_m(VALUE self, VALUE args)
{
    VALUE v;
    if (RARRAY_LEN(args) == 1 &&
        !NIL_P(v = rb_check_array_type(rb_ary_entry(args, 0)))) {
        return rb_reg_s_union(self, v);
    }
    return rb_reg_s_union(self, args);
}