Method: Float#floor

Defined in:

numeric.c

#floor(*args) ⇒ Object

:markup: markdown

call-seq:

floor(ndigits = 0) -> float or integer

Returns a float or integer that is a “floor” value for ‘self`, as specified by `ndigits`, which must be an [integer-convertible object](implicit_conversion.rdoc@Integer-Convertible+Objects).

When ‘self` is zero, returns a zero value: a float if `ndigits` is positive, an integer otherwise:

“‘ f = 0.0 # => 0.0 f.floor(20) # => 0.0 f.floor(0) # => 0 f.floor(-20) # => 0 “`

When ‘self` is non-zero and `ndigits` is positive, returns a float with `ndigits` digits after the decimal point (as available):

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

When ‘self` is non-zero and `ndigits` is non-positive, returns an integer value 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.floor(ndigits) | |——–:|————:|————————–:| | 0 | 1 | 12345 | | -1 | 10 | 12340 | | -2 | 100 | 12300 | | -3 | 1000 | 12000 | | -4 | 10000 | 10000 | | -5 | 100000 | 0 |

Examples with negative ‘self`:

| ndigits | Granularity | -12345.6789.floor(ndigits) | |——–:|————:|—————————:| | 0 | 1 | -12346 | | -1 | 10 | -12350 | | -2 | 100 | -12400 | | -3 | 1000 | -13000 | | -4 | 10000 | -20000 | | -5 | 100000 | -100000 | | -6 | 1000000 | -1000000 |

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

“‘ (0.3 / 0.1).floor # => 2 # Not 3, (because (0.3 / 0.1) # => 2.9999999999999996, not 3.0) “`

Related: Float#ceil.

# File 'numeric.c', line 2216

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