Calls the block with each successive overlapped n
-tuple of elements; returns self
:
a = [] (1..5).each_cons(3) {|element| a.push(element) } a # => [[1, 2, 3], [2, 3, 4], [3, 4, 5]] a = [] h = {foo: 0, bar: 1, baz: 2, bam: 3} h.each_cons(2) {|element| a.push(element) } a # => [[[:foo, 0], [:bar, 1]], [[:bar, 1], [:baz, 2]], [[:baz, 2], [:bam, 3]]]
With no block given, returns an Enumerator
.
Creates an enumerator for each chunked elements. The beginnings of chunks are defined by the block.
This method splits each chunk using adjacent elements, elt_before and elt_after, in the receiver enumerator. This method split chunks between elt_before and elt_after where the block returns false
.
The block is called the length of the receiver enumerator minus one.
The result enumerator yields the chunked elements as an array. So each
method can be called as follows:
enum.chunk_while { |elt_before, elt_after| bool }.each { |ary| ... }
Other methods of the Enumerator
class and Enumerable
module, such as to_a
, map
, etc., are also usable.
For example, one-by-one increasing subsequence can be chunked as follows:
a = [1,2,4,9,10,11,12,15,16,19,20,21] b = a.chunk_while {|i, j| i+1 == j } p b.to_a #=> [[1, 2], [4], [9, 10, 11, 12], [15, 16], [19, 20, 21]] c = b.map {|a| a.length < 3 ? a : "#{a.first}-#{a.last}" } p c #=> [[1, 2], [4], "9-12", [15, 16], "19-21"] d = c.join(",") p d #=> "1,2,4,9-12,15,16,19-21"
Increasing (non-decreasing) subsequence can be chunked as follows:
a = [0, 9, 2, 2, 3, 2, 7, 5, 9, 5] p a.chunk_while {|i, j| i <= j }.to_a #=> [[0, 9], [2, 2, 3], [2, 7], [5, 9], [5]]
Adjacent evens and odds can be chunked as follows: (Enumerable#chunk
is another way to do it.)
a = [7, 5, 9, 2, 0, 7, 9, 4, 2, 0] p a.chunk_while {|i, j| i.even? == j.even? }.to_a #=> [[7, 5, 9], [2, 0], [7, 9], [4, 2, 0]]
Enumerable#slice_when
does the same, except splitting when the block returns true
instead of false
.
Sets create identifier, which is used to decide if the json_create hook of a class should be called; initial value is json_class
:
JSON.create_id # => 'json_class'
Returns the current create identifier. See also JSON.create_id=
.
Arguments obj
and opts
here are the same as arguments obj
and opts
in JSON.generate
.
By default, generates JSON data without checking for circular references in obj
(option max_nesting
set to false
, disabled).
Raises an exception if obj
contains circular references:
a = []; b = []; a.push(b); b.push(a) # Raises SystemStackError (stack level too deep): JSON.fast_generate(a)
Arguments obj
and opts
here are the same as arguments obj
and opts
in JSON.generate
.
Default options are:
{ indent: ' ', # Two spaces space: ' ', # One space array_nl: "\n", # Newline object_nl: "\n" # Newline }
Example:
obj = {foo: [:bar, :baz], bat: {bam: 0, bad: 1}} json = JSON.pretty_generate(obj) puts json
Output:
{ "foo": [ "bar", "baz" ], "bat": { "bam": 0, "bad": 1 } }
Enters exclusive section and executes the block. Leaves the exclusive section automatically when the block exits. See example under MonitorMixin
.
Returns the source file origin from the given object
.
See ::trace_object_allocations
for more information and examples.
Returns the original line from source for from the given object
.
See ::trace_object_allocations
for more information and examples.
Calls the block once for each living, nonimmediate object in this Ruby
process. If module is specified, calls the block for only those classes or modules that match (or are a subclass of) module. Returns the number of objects found. Immediate objects (Fixnum
s, Symbol
s true
, false
, and nil
) are never returned. In the example below, each_object returns both the numbers we defined and several constants defined in the Math
module.
If no block is given, an enumerator is returned instead.
a = 102.7 b = 95 # Won't be returned c = 12345678987654321 count = ObjectSpace.each_object(Numeric) {|x| p x } puts "Total count: #{count}"
produces:
12345678987654321 102.7 2.71828182845905 3.14159265358979 2.22044604925031e-16 1.7976931348623157e+308 2.2250738585072e-308 Total count: 7
Returns information for heaps in the GC.
If the first optional argument, heap_name
, is passed in and not nil
, it returns a Hash
containing information about the particular heap. Otherwise, it will return a Hash
with heap names as keys and a Hash
containing information about the heap as values.
If the second optional argument, hash_or_key
, is given as a Hash
, it will be overwritten and returned. This is intended to avoid the probe effect.
If both optional arguments are passed in and the second optional argument is a symbol, it will return a Numeric
value for the particular heap.
On CRuby, heap_name
is of the type Integer
but may be of type String
on other implementations.
The contents of the hash are implementation-specific and may change in the future without notice.
If the optional argument, hash, is given, it is overwritten and returned.
This method is only expected to work on CRuby.
The hash includes the following keys about the internal information in the GC:
The slot size of the heap in bytes.
The number of pages that can be allocated without triggering a new garbage collection cycle.
The number of pages in the eden heap.
The total number of slots in all of the pages in the eden heap.
The number of pages in the tomb heap. The tomb heap only contains pages that do not have any live objects.
The total number of slots in all of the pages in the tomb heap.
The total number of pages that have been allocated in the heap.
The total number of pages that have been freed and released back to the system in the heap.
The number of times this heap has forced major garbage collection cycles to start due to running out of free slots.
The number of times this heap has forced incremental marking to complete due to running out of pooled slots.
Try to activate a gem containing path
. Returns true if activation succeeded or wasn’t needed because it was already activated. Returns false if it can’t find the path in a gem.
Find
the full path to the executable for gem name
. If the exec_name
is not given, an exception will be raised, otherwise the specified executable’s path is returned. requirements
allows you to specify specific gem versions.
Reset the dir
and path
values. The next time dir
or path
is requested, the values will be calculated from scratch. This is mainly used by the unit tests to provide test isolation.
Glob pattern for require-able path suffixes.
Use the home
and paths
values for Gem.dir
and Gem.path
. Used mainly by the unit tests to provide environment isolation.
Is this a windows platform?
Is this a java platform?
Is this platform Solaris?
Is this platform FreeBSD
The path to standard location of the user’s state file.
The path to standard location of the user’s cache directory.
The path to standard location of the user’s data directory.
The path to standard location of the user’s state directory.