Returns an array of flattened objects returned by the block.
With a block given, calls the block with successive elements; returns a flattened array of objects returned by the block:
[0, 1, 2, 3].flat_map {|element| -element } # => [0, -1, -2, -3] [0, 1, 2, 3].flat_map {|element| [element, -element] } # => [0, 0, 1, -1, 2, -2, 3, -3] [[0, 1], [2, 3]].flat_map {|e| e + [100] } # => [0, 1, 100, 2, 3, 100] {foo: 0, bar: 1, baz: 2}.flat_map {|key, value| [key, value] } # => [:foo, 0, :bar, 1, :baz, 2]
With no block given, returns an Enumerator.
Alias: collect_concat
.
Returns an array of flattened objects returned by the block.
With a block given, calls the block with successive elements; returns a flattened array of objects returned by the block:
[0, 1, 2, 3].flat_map {|element| -element } # => [0, -1, -2, -3] [0, 1, 2, 3].flat_map {|element| [element, -element] } # => [0, 0, 1, -1, 2, -2, 3, -3] [[0, 1], [2, 3]].flat_map {|e| e + [100] } # => [0, 1, 100, 2, 3, 100] {foo: 0, bar: 1, baz: 2}.flat_map {|key, value| [key, value] } # => [:foo, 0, :bar, 1, :baz, 2]
With no block given, returns an Enumerator.
Alias: collect_concat
.
Calls the block with successive elements as long as the block returns a truthy value; returns an array of all elements up to that point:
(1..4).take_while{|i| i < 3 } # => [1, 2] h = {foo: 0, bar: 1, baz: 2} h.take_while{|element| key, value = *element; value < 2 } # => [[:foo, 0], [:bar, 1]]
With no block given, returns an Enumerator
.
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 } }
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.
Returns the table for calculating CRC checksum as an array.
Returns true
if the named file is readable by the real user and group id of this process. See access(3).
Note that some OS-level security features may cause this to return true even though the file is not readable by the real user/group.
If file_name is readable by others, returns an integer representing the file permission bits of file_name. Returns nil
otherwise. The meaning of the bits is platform dependent; on Unix systems, see stat(2)
.
file_name can be an IO
object.
File.world_readable?("/etc/passwd") #=> 420 m = File.world_readable?("/etc/passwd") sprintf("%o", m) #=> "644"
Returns true
if the named file is writable by the real user and group id of this process. See access(3).
Note that some OS-level security features may cause this to return true even though the file is not writable by the real user/group.
If file_name is writable by others, returns an integer representing the file permission bits of file_name. Returns nil
otherwise. The meaning of the bits is platform dependent; on Unix systems, see stat(2)
.
file_name can be an IO
object.
File.world_writable?("/tmp") #=> 511 m = File.world_writable?("/tmp") sprintf("%o", m) #=> "777"
Returns true
if the named file is executable by the real user and group id of this process. See access(3).
Windows does not support execute permissions separately from read permissions. On Windows, a file is only considered executable if it ends in .bat, .cmd, .com, or .exe.
Note that some OS-level security features may cause this to return true even though the file is not executable by the real user/group.
Returns the number of malloc() allocations.
Only available if ruby was built with CALC_EXACT_MALLOC_SIZE
.
Return measured GC total time in nano seconds.
Start a dRuby server locally.
The new dRuby server will become the primary server, even if another server is currently the primary server.
uri
is the URI
for the server to bind to. If nil, the server will bind to random port on the default local host name and use the default dRuby protocol.
front
is the server’s front object. This may be nil.
config
is the configuration for the new server. This may be nil.
See DRbServer::new
.
Start a dRuby server locally.
The new dRuby server will become the primary server, even if another server is currently the primary server.
uri
is the URI
for the server to bind to. If nil, the server will bind to random port on the default local host name and use the default dRuby protocol.
front
is the server’s front object. This may be nil.
config
is the configuration for the new server. This may be nil.
See DRbServer::new
.
Takes a hash as its argument. The key is a symbol or an array of symbols. These symbols correspond to method names. The value is the accessor to which the methods will be delegated.