Method: Integer#floor

Defined in:

numeric.c

#floor(*args) ⇒ Object

:markup: markdown

call-seq:

floor(ndigits = 0) -> integer

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

• When self is zero, returns zero (regardless of the value of ndigits):

  ```
  0.floor(2)  # => 0
  0.floor(-2) # => 0
  ```
  

• When self is non-zero and ndigits is non-negative, returns self:

  ```
  555.floor     # => 555
  555.floor(50) # => 555
  ```
  

• When self is non-zero and ndigits is negative, returns a 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 | 1234.floor(ndigits) |
  |--------:|------------:|--------------------:|
  | -1      | 10          | 1230                |
  | -2      | 100         | 1200                |
  | -3      | 1000        | 1000                |
  | -4      | 10000       | 0                   |
  | -5      | 100000      | 0                   |
  
  Examples with negative `self`:
  
  | ndigits | Granularity | -1234.floor(ndigits) |
  |--------:|------------:|---------------------:|
  | -1      | 10          | -1240                |
  | -2      | 100         | -1300                |
  | -3      | 1000        | -2000                |
  | -4      | 10000       | -10000               |
  | -5      | 100000      | -100000              |
  

Related: Integer#ceil.

# File 'numeric.c', line 5852

static VALUE
int_floor(int argc, VALUE* argv, VALUE num)
{
    int ndigits;

    if (!rb_check_arity(argc, 0, 1)) return num;
    ndigits = NUM2INT(argv[0]);
    if (ndigits >= 0) {
        return num;
    }
    return rb_int_floor(num, ndigits);
}