instance method
Float#ceil
() -> ::Integer
(::int digits) -> (::Integer | ::Float)
ceil(ndigits = 0) → float or integer
numeric.c
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static VALUE
flo_ceil(int argc, VALUE *argv, VALUE num)
{
int ndigits = flo_ndigits(argc, argv);
return rb_float_ceil(num, ndigits);
}
Returns a numeric that is a “ceiling” value for self, as specified by the given ndigits, which must be an integer-convertible object.
When ndigits is positive, returns a Float with ndigits decimal digits after the decimal point (as available, but no fewer than 1):
Example
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:
Example
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:
Example
(2.1 / 0.7).ceil #=> 4 # Not 3 (because 2.1 / 0.7 # => 3.0000000000000004, not 3.0)
Related: Float#floor.