Method: Float#ceil

Defined in:

numeric.c

#ceil(*args) ⇒ Object

:markup: markdown

call-seq:

ceil(ndigits = 0) -> float or integer

Returns a numeric that is a “ceiling” value for self, as specified by the given ndigits, which must be an [integer-convertible object](implicit_conversion.rdoc@Integer-Convertible+Objects).

When ndigits is positive, returns a Float with ndigits decimal digits after the decimal point (as available, but no fewer than 1):

“‘ f = 12345.6789 f.ceil(1) # => 12345.7 f.ceil(3) # => 12345.679 f.ceil(30) # => 12345.6789 f = -12345.6789 f.ceil(1) # => -12345.6 f.ceil(3) # => -12345.678 f.ceil(30) # => -12345.6789 f = 0.0 f.ceil(1) # => 0.0 f.ceil(100) # => 0.0 “`

When ndigits is non-positive, returns an Integer based on a computed granularity:

• The granularity is ‘10 ** ndigits.abs`.

• The returned value is the largest multiple of the granularity that is less than or equal to self.

Examples with positive self:

| ndigits | Granularity | 12345.6789.ceil(ndigits) | |——–:|————:|————————-:| | 0 | 1 | 12346 | | -1 | 10 | 12350 | | -2 | 100 | 12400 | | -3 | 1000 | 13000 | | -4 | 10000 | 20000 | | -5 | 100000 | 100000 |

Examples with negative self:

| ndigits | Granularity | -12345.6789.ceil(ndigits) | |——–:|————:|————————–:| | 0 | 1 | -12345 | | -1 | 10 | -12340 | | -2 | 100 | -12300 | | -3 | 1000 | -12000 | | -4 | 10000 | -10000 | | -5 | 100000 | 0 |

When self is zero and ndigits is non-positive, returns Integer zero:

“‘ 0.0.ceil(0) # => 0 0.0.ceil(-1) # => 0 0.0.ceil(-2) # => 0 “`

Note that the limited precision of floating-point arithmetic may lead to surprising results:

“‘ (2.1 / 0.7).ceil #=> 4 # Not 3 (because 2.1 / 0.7 # => 3.0000000000000004, not 3.0) “`

Related: Float#floor.

# File 'numeric.c', line 2301

static VALUE
flo_ceil(int argc, VALUE *argv, VALUE num)
{
    int ndigits = flo_ndigits(argc, argv);
    return rb_float_ceil(num, ndigits);
}