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instance method

Float#<=>

self <=> other → -1, 0, +1, or nil

static VALUE
flo_cmp(VALUE x, VALUE y)
{
    double a, b;
    VALUE i;

    a = RFLOAT_VALUE(x);
    if (isnan(a)) return Qnil;
    if (RB_INTEGER_TYPE_P(y)) {
        VALUE rel = rb_integer_float_cmp(y, x);
        if (FIXNUM_P(rel))
            return LONG2FIX(-FIX2LONG(rel));
        return rel;
    }
    else if (RB_FLOAT_TYPE_P(y)) {
        b = RFLOAT_VALUE(y);
    }
    else {
        if (isinf(a) && !UNDEF_P(i = rb_check_funcall(y, rb_intern("infinite?"), 0, 0))) {
            if (RTEST(i)) {
                int j = rb_cmpint(i, x, y);
                j = (a > 0.0) ? (j > 0 ? 0 : +1) : (j < 0 ? 0 : -1);
                return INT2FIX(j);
            }
            if (a > 0.0) return INT2FIX(1);
            return INT2FIX(-1);
        }
        return rb_num_coerce_cmp(x, y, id_cmp);
    }
    return rb_dbl_cmp(a, b);
}

Returns a value that depends on the numeric relation between self and other:

-1, if self is less than other.
0, if self is equal to other.
1, if self is greater than other.
nil, if the two values are incommensurate.

Examples:

Example

2.0 <=> 2              # => 0
2.0 <=> 2.0            # => 0
2.0 <=> Rational(2, 1) # => 0
2.0 <=> Complex(2, 0)  # => 0
2.0 <=> 1.9            # => 1
2.0 <=> 2.1            # => -1
2.0 <=> 'foo'          # => nil

This is the basis for the tests in the Comparable module.

Float::NAN <=> Float::NAN returns an implementation-dependent value.

See also #<= #== #< #=== also in 4.1 · 4.0 · 3.4 · 3.3 · 3.1 · 3.0

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