Class: NilClass
Relationships & Source Files | |
Inherits: | Object |
Defined in: | object.c, complex.c, nilclass.rb, object.c, rational.c |
Overview
The class of the singleton object nil
.
Several of its methods act as operators:
Others act as converters, carrying the concept of nullity to other classes:
Another method provides inspection:
Finally, there is this query method:
Instance Attribute Summary
-
#nil? ⇒ Boolean
readonly
Returns
true
.
Instance Method Summary
-
#&(object) ⇒ false
Returns
false
: - #===
-
#=~(object) ⇒ nil
Returns
nil
. - #^
-
#inspect ⇒ 'nil'
Returns string
'nil'
: -
#rationalize(eps = nil) ⇒ 1
Returns zero as a
::Rational
: -
#to_a ⇒ Array
Returns an empty
::Array
. -
#to_c ⇒ (0+0i)
Returns zero as a
::Complex
: -
#to_f ⇒ 0.0
Always returns zero.
-
#to_h ⇒ {}
Returns an empty
::Hash
. -
#to_i ⇒ 0
Always returns zero.
-
#to_r ⇒ 1
Returns zero as a
::Rational
: -
#to_s ⇒ ''
Returns an empty
::String
: - #|
Instance Attribute Details
#nil? ⇒ Boolean
(readonly)
Returns true
. For all other objects, method nil?
returns false
.
# File 'object.c', line 1640
static VALUE rb_true(VALUE obj) { return Qtrue; }
Instance Method Details
#&(object) ⇒ false
#&(object) ⇒ false
false
#&(object) ⇒ false
# File 'object.c', line 1595
static VALUE false_and(VALUE obj, VALUE obj2) { return Qfalse; }
#===
[ GitHub ]
#=~(object) ⇒ nil
Returns nil
.
This method makes it useful to write:
while gets =~ /re/
# ...
end
# File 'object.c', line 1450
static VALUE nil_match(VALUE obj1, VALUE obj2) { return Qnil; }
#^
[ GitHub ]
#inspect ⇒ 'nil
'
Returns string 'nil'
:
nil.inspect # => "nil"
# File 'object.c', line 1430
static VALUE nil_inspect(VALUE obj) { return rb_usascii_str_new2("nil"); }
#rationalize(eps = nil) ⇒ 1
# File 'rational.c', line 2137
static VALUE nilclass_rationalize(int argc, VALUE *argv, VALUE self) { rb_check_arity(argc, 0, 1); return nilclass_to_r(self); }
#to_a ⇒ Array
Returns an empty ::Array
.
nil.to_a # => []
# File 'object.c', line 1396
static VALUE nil_to_a(VALUE obj) { return rb_ary_new2(0); }
#to_c ⇒ (0
+0i
)
Returns zero as a ::Complex
:
nil.to_c # => (0+0i)
# File 'complex.c', line 1936
static VALUE nilclass_to_c(VALUE self) { return rb_complex_new1(INT2FIX(0)); }
#to_f ⇒ 0
.0
Always returns zero.
nil.to_f #=> 0.0
# File 'nilclass.rb', line 22
def to_f return 0.0 end
#to_h ⇒ {}
Returns an empty ::Hash
.
nil.to_h #=> {}
# File 'object.c', line 1414
static VALUE nil_to_h(VALUE obj) { return rb_hash_new(); }
#to_i ⇒ 0
Always returns zero.
nil.to_i #=> 0
# File 'nilclass.rb', line 10
def to_i return 0 end
#to_r ⇒ 1
Returns zero as a ::Rational
:
nil.to_r # => (0/1)
# File 'rational.c', line 2120
static VALUE nilclass_to_r(VALUE self) { return rb_rational_new1(INT2FIX(0)); }
#to_s ⇒ ''
Returns an empty ::String
:
nil.to_s # => ""
# File 'object.c', line 1378
VALUE rb_nil_to_s(VALUE obj) { return rb_cNilClass_to_s; }