Range#size

() -> ::Integer?

() -> ::Float?

size → non_negative_integer or Infinity or nil

static VALUE
range_size(VALUE range)
{
    VALUE b = RANGE_BEG(range), e = RANGE_END(range);

    if (RB_INTEGER_TYPE_P(b)) {
        if (rb_obj_is_kind_of(e, rb_cNumeric)) {
            return ruby_num_interval_step_size(b, e, INT2FIX(1), EXCL(range));
        }
        if (NIL_P(e)) {
            return DBL2NUM(HUGE_VAL);
        }
    }

    if (!discrete_object_p(b)) {
        CANT_ITERATE_FROM(b);
    }

    return Qnil;
}

Returns the count of elements in self if both begin and end values are numeric; otherwise, returns nil:

Example

(1..4).size      # => 4
(1...4).size     # => 3
(1..).size       # => Infinity
('a'..'z').size  # => nil

If self is not iterable, raises an exception:

Example

(0.5..2.5).size  # TypeError
(..1).size       # TypeError

Related: Range#count.

Ruby version changes

3.4
- Range#size now raises TypeError if the range is not iterable. [Misc #18984]

See also #reverse_each #step #overlap? #to_a also in 4.1 · 4.0 · 3.3 · 3.2 · 3.1 · 3.0

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