instance method

Date#>>

(::Integer month) -> ::Date

d >> n → new_date

static VALUE
d_lite_rshift(VALUE self, VALUE other)
{
    VALUE t, y, nth, rjd2;
    int m, d, rjd;
    double sg;

    get_d1(self);
    t = f_add3(f_mul(m_real_year(dat), INT2FIX(12)),
               INT2FIX(m_mon(dat) - 1),
               other);
    if (FIXNUM_P(t)) {
        long it = FIX2LONG(t);
        y = LONG2NUM(DIV(it, 12));
        it = MOD(it, 12);
        m = (int)it + 1;
    }
    else {
        y = f_idiv(t, INT2FIX(12));
        t = f_mod(t, INT2FIX(12));
        m = FIX2INT(t) + 1;
    }
    d = m_mday(dat);
    sg = m_sg(dat);

    while (1) {
        int ry, rm, rd, ns;

        if (valid_civil_p(y, m, d, sg,
                          &nth, &ry,
                          &rm, &rd, &rjd, &ns))
            break;
        if (--d < 1)
            rb_raise(eDateError, "invalid date");
    }
    encode_jd(nth, rjd, &rjd2);
    return d_lite_plus(self, f_sub(rjd2, m_real_local_jd(dat)));
}

Returns a new Date object representing the date n months later; n should be a numeric:

Example

(Date.new(2001, 2, 3) >> 1).to_s  # => "2001-03-03"
(Date.new(2001, 2, 3) >> -2).to_s # => "2000-12-03"

When the same day does not exist for the new month, the last day of that month is used instead:

Example

(Date.new(2001, 1, 31) >> 1).to_s  # => "2001-02-28"
(Date.new(2001, 1, 31) >> -4).to_s # => "2000-09-30"

This results in the following, possibly unexpected, behaviors:

Example

d0 = Date.new(2001, 1, 31)
d1 = d0 >> 1 # => #<Date: 2001-02-28>
d2 = d1 >> 1 # => #<Date: 2001-03-28>

d0 = Date.new(2001, 1, 31)
d1 = d0 >> 1  # => #<Date: 2001-02-28>
d2 = d1 >> -1 # => #<Date: 2001-01-28>

See also #=== #ajd #<=> #amjd also in 4.1 · 3.4 · 3.3 · 3.2 · 3.1 · 3.0

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