Insert or update key-value pairs.
This method will work with any object which implements an each_pair
method, such as a Hash
.
Adds the contents of the given hashes to the receiver.
If no block is given, entries with duplicate keys are overwritten with the values from each other_hash
successively, otherwise the value for each duplicate key is determined by calling the block with the key, its value in the receiver and its value in each other_hash
.
h1 = { "a" => 100, "b" => 200 } h1.merge! #=> {"a"=>100, "b"=>200} h1 #=> {"a"=>100, "b"=>200} h1 = { "a" => 100, "b" => 200 } h2 = { "b" => 246, "c" => 300 } h1.merge!(h2) #=> {"a"=>100, "b"=>246, "c"=>300} h1 #=> {"a"=>100, "b"=>246, "c"=>300} h1 = { "a" => 100, "b" => 200 } h2 = { "b" => 246, "c" => 300 } h3 = { "b" => 357, "d" => 400 } h1.merge!(h2, h3) #=> {"a"=>100, "b"=>357, "c"=>300, "d"=>400} h1 #=> {"a"=>100, "b"=>357, "c"=>300, "d"=>400} h1 = { "a" => 100, "b" => 200 } h2 = { "b" => 246, "c" => 300 } h3 = { "b" => 357, "d" => 400 } h1.merge!(h2, h3) {|key, v1, v2| v1 } #=> {"a"=>100, "b"=>200, "c"=>300, "d"=>400} h1 #=> {"a"=>100, "b"=>200, "c"=>300, "d"=>400}
Hash#update
is an alias for Hash#merge!
.
Adds the contents of hash
to the environment variables. If no block is specified entries with duplicate keys are overwritten, otherwise the value of each duplicate name is determined by calling the block with the key, its value from the environment and its value from the hash.
Returns true
iff the current severity level allows for the printing of FATAL
messages.
Returns true
if this is a permutation matrix Raises an error if matrix is not square.
Returns internal information of TracePoint
.
The contents of the returned value are implementation specific. It may be changed in future.
This method is only for debugging TracePoint
itself.
Returns the status of thr
.
"sleep"
Returned if this thread is sleeping or waiting on I/O
"run"
When this thread is executing
"aborting"
If this thread is aborting
false
When this thread is terminated normally
nil
If terminated with an exception.
a = Thread.new { raise("die now") } b = Thread.new { Thread.stop } c = Thread.new { Thread.exit } d = Thread.new { sleep } d.kill #=> #<Thread:0x401b3678 aborting> a.status #=> nil b.status #=> "sleep" c.status #=> false d.status #=> "aborting" Thread.current.status #=> "run"
Computes the arctangent of decimal
to the specified number of digits of precision, numeric
.
If decimal
is NaN, returns NaN.
BigMath.atan(BigDecimal('-1'), 16).to_s #=> "-0.785398163397448309615660845819878471907514682065e0"
Returns a Hash
containing information about the GC
.
The hash includes information about internal statistics about GC
such as:
{ :count=>0, :heap_allocated_pages=>24, :heap_sorted_length=>24, :heap_allocatable_pages=>0, :heap_available_slots=>9783, :heap_live_slots=>7713, :heap_free_slots=>2070, :heap_final_slots=>0, :heap_marked_slots=>0, :heap_eden_pages=>24, :heap_tomb_pages=>0, :total_allocated_pages=>24, :total_freed_pages=>0, :total_allocated_objects=>7796, :total_freed_objects=>83, :malloc_increase_bytes=>2389312, :malloc_increase_bytes_limit=>16777216, :minor_gc_count=>0, :major_gc_count=>0, :remembered_wb_unprotected_objects=>0, :remembered_wb_unprotected_objects_limit=>0, :old_objects=>0, :old_objects_limit=>0, :oldmalloc_increase_bytes=>2389760, :oldmalloc_increase_bytes_limit=>16777216 }
The contents of the hash are implementation specific and may be changed in the future.
This method is only expected to work on C Ruby.
Returns the arc tangent of z
CMath.atan(1 + 1i) #=> (1.0172219678978514+0.4023594781085251i)
returns the arc tangent of y
divided by x
using the signs of y
and x
to determine the quadrant
CMath.atan2(1 + 1i, 0) #=> (1.5707963267948966+0.0i)
returns the inverse hyperbolic tangent of z
CMath.atanh(1 + 1i) #=> (0.4023594781085251+1.0172219678978514i)
Returns the arc tangent of z
CMath.atan(1 + 1i) #=> (1.0172219678978514+0.4023594781085251i)
returns the arc tangent of y
divided by x
using the signs of y
and x
to determine the quadrant
CMath.atan2(1 + 1i, 0) #=> (1.5707963267948966+0.0i)
returns the inverse hyperbolic tangent of z
CMath.atanh(1 + 1i) #=> (0.4023594781085251+1.0172219678978514i)
Returns true if new
is newer than all old_list
. Non-existent files are older than any file.
FileUtils.uptodate?('hello.o', %w(hello.c hello.h)) or \ system 'make hello.o'
Returns true if new
is newer than all old_list
. Non-existent files are older than any file.
FileUtils.uptodate?('hello.o', %w(hello.c hello.h)) or \ system 'make hello.o'
Computes the arc tangent given y
and x
. Returns a Float
in the range -PI..PI. Return value is a angle in radians between the positive x-axis of cartesian plane and the point given by the coordinates (x
, y
) on it.
Domain: (-INFINITY, INFINITY)
Codomain: [-PI, PI]
Math.atan2(-0.0, -1.0) #=> -3.141592653589793 Math.atan2(-1.0, -1.0) #=> -2.356194490192345 Math.atan2(-1.0, 0.0) #=> -1.5707963267948966 Math.atan2(-1.0, 1.0) #=> -0.7853981633974483 Math.atan2(-0.0, 1.0) #=> -0.0 Math.atan2(0.0, 1.0) #=> 0.0 Math.atan2(1.0, 1.0) #=> 0.7853981633974483 Math.atan2(1.0, 0.0) #=> 1.5707963267948966 Math.atan2(1.0, -1.0) #=> 2.356194490192345 Math.atan2(0.0, -1.0) #=> 3.141592653589793 Math.atan2(INFINITY, INFINITY) #=> 0.7853981633974483 Math.atan2(INFINITY, -INFINITY) #=> 2.356194490192345 Math.atan2(-INFINITY, INFINITY) #=> -0.7853981633974483 Math.atan2(-INFINITY, -INFINITY) #=> -2.356194490192345
Computes the arc tangent of x
. Returns -PI/2..PI/2.
Domain: (-INFINITY, INFINITY)
Codomain: (-PI/2, PI/2)
Math.atan(0) #=> 0.0
Computes the inverse hyperbolic tangent of x
.
Domain: (-1, 1)
Codomain: (-INFINITY, INFINITY)
Math.atanh(1) #=> Infinity
Counts objects for each T_DATA
type.
This method is only for MRI developers interested in performance and memory usage of Ruby programs.
It returns a hash as:
{RubyVM::InstructionSequence=>504, :parser=>5, :barrier=>6, :mutex=>6, Proc=>60, RubyVM::Env=>57, Mutex=>1, Encoding=>99, ThreadGroup=>1, Binding=>1, Thread=>1, RubyVM=>1, :iseq=>1, Random=>1, ARGF.class=>1, Data=>1, :autoload=>3, Time=>2} # T_DATA objects existing at startup on r32276.
If the optional argument, result_hash, is given, it is overwritten and returned. This is intended to avoid probe effect.
The contents of the returned hash is implementation specific and may change in the future.
In this version, keys are Class
object or Symbol
object.
If object is kind of normal (accessible) object, the key is Class
object. If object is not a kind of normal (internal) object, the key is symbol name, registered by rb_data_type_struct.
This method is only expected to work with C Ruby.