Creates a new Pathname object from the given string, path, and returns pathname object.
In order to use this constructor, you must first require the Pathname standard library extension.
require 'pathname' Pathname("/home/zzak") #=> #<Pathname:/home/zzak>
See also Pathname::new for more information.
Equivalent to:
$stdout.putc(int)
Refer to the documentation for IO#putc for important information regarding multi-byte characters.
Returns arg converted to a float. Numeric types are converted directly, and with exception to String and nil the rest are converted using arg.to_f. Converting a String with invalid characters will result in a ArgumentError. Converting nil generates a TypeError. Exceptions can be suppressed by passing exception: false.
Float(1) #=> 1.0 Float("123.456") #=> 123.456 Float("123.0_badstring") #=> ArgumentError: invalid value for Float(): "123.0_badstring" Float(nil) #=> TypeError: can't convert nil into Float Float("123.0_badstring", exception: false) #=> nil
Returns x/y or arg as a Rational.
Rational(2, 3) #=> (2/3) Rational(5) #=> (5/1) Rational(0.5) #=> (1/2) Rational(0.3) #=> (5404319552844595/18014398509481984) Rational("2/3") #=> (2/3) Rational("0.3") #=> (3/10) Rational("10 cents") #=> ArgumentError Rational(nil) #=> TypeError Rational(1, nil) #=> TypeError Rational("10 cents", exception: false) #=> nil
Syntax of the string form:
string form = extra spaces , rational , extra spaces ;
rational = [ sign ] , unsigned rational ;
unsigned rational = numerator | numerator , "/" , denominator ;
numerator = integer part | fractional part | integer part , fractional part ;
denominator = digits ;
integer part = digits ;
fractional part = "." , digits , [ ( "e" | "E" ) , [ sign ] , digits ] ;
sign = "-" | "+" ;
digits = digit , { digit | "_" , digit } ;
digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;
extra spaces = ? \s* ? ;
See also String#to_r.
Equivalent to ($_.dup).chop!, except nil is never returned. See String#chop!. Available only when -p/-n command line option specified.
Equivalent to $_ = $_.chomp(string). See String#chomp. Available only when -p/-n command line option specified.
Deprecated. Use block_given? instead.
Returns an array of objects returned by the block.
With a block given, calls the block with successive elements; returns an array of the objects returned by the block:
(0..4).map {|i| i*i } # => [0, 1, 4, 9, 16] {foo: 0, bar: 1, baz: 2}.map {|key, value| value*2} # => [0, 2, 4]
With no block given, returns an Enumerator.
Returns the element with the maximum element according to a given criterion. The ordering of equal elements is indeterminate and may be unstable.
With no argument and no block, returns the maximum element, using the elements’ own method <=> for comparison:
(1..4).max # => 4 (-4..-1).max # => -1 %w[d c b a].max # => "d" {foo: 0, bar: 1, baz: 2}.max # => [:foo, 0] [].max # => nil
With positive integer argument n given, and no block, returns an array containing the first n maximum elements that exist:
(1..4).max(2) # => [4, 3] (-4..-1).max(2) # => [-1, -2] %w[d c b a].max(2) # => ["d", "c"] {foo: 0, bar: 1, baz: 2}.max(2) # => [[:foo, 0], [:baz, 2]] [].max(2) # => []
With a block given, the block determines the maximum elements. The block is called with two elements a and b, and must return:
A negative integer if a < b.
Zero if a == b.
A positive integer if a > b.
With a block given and no argument, returns the maximum element as determined by the block:
%w[xxx x xxxx xx].max {|a, b| a.size <=> b.size } # => "xxxx" h = {foo: 0, bar: 1, baz: 2} h.max {|pair1, pair2| pair1[1] <=> pair2[1] } # => [:baz, 2] [].max {|a, b| a <=> b } # => nil
With a block given and positive integer argument n given, returns an array containing the first n maximum elements that exist, as determined by the block.
%w[xxx x xxxx xx].max(2) {|a, b| a.size <=> b.size } # => ["xxxx", "xxx"] h = {foo: 0, bar: 1, baz: 2} h.max(2) {|pair1, pair2| pair1[1] <=> pair2[1] } # => [[:baz, 2], [:bar, 1]] [].max(2) {|a, b| a <=> b } # => []
Each element in the returned enumerator is a 2-element array consisting of:
A value returned by the block.
An array (“chunk”) containing the element for which that value was returned, and all following elements for which the block returned the same value:
So that:
Each block return value that is different from its predecessor begins a new chunk.
Each block return value that is the same as its predecessor continues the same chunk.
Example:
e = (0..10).chunk {|i| (i / 3).floor } # => #<Enumerator: ...> # The enumerator elements. e.next # => [0, [0, 1, 2]] e.next # => [1, [3, 4, 5]] e.next # => [2, [6, 7, 8]] e.next # => [3, [9, 10]]
Method chunk is especially useful for an enumerable that is already sorted. This example counts words for each initial letter in a large array of words:
# Get sorted words from a web page. url = 'https://raw.githubusercontent.com/eneko/data-repository/master/data/words.txt' words = URI::open(url).readlines # Make chunks, one for each letter. e = words.chunk {|word| word.upcase[0] } # => #<Enumerator: ...> # Display 'A' through 'F'. e.each {|c, words| p [c, words.length]; break if c == 'F' }
Output:
["A", 17096] ["B", 11070] ["C", 19901] ["D", 10896] ["E", 8736] ["F", 6860]
You can use the special symbol :_alone to force an element into its own separate chuck:
a = [0, 0, 1, 1] e = a.chunk{|i| i.even? ? :_alone : true } e.to_a # => [[:_alone, [0]], [:_alone, [0]], [true, [1, 1]]]
For example, you can put each line that contains a URL into its own chunk:
pattern = /http/ open(filename) { |f| f.chunk { |line| line =~ pattern ? :_alone : true }.each { |key, lines| pp lines } }
You can use the special symbol :_separator or nil to force an element to be ignored (not included in any chunk):
a = [0, 0, -1, 1, 1] e = a.chunk{|i| i < 0 ? :_separator : true } e.to_a # => [[true, [0, 0]], [true, [1, 1]]]
Note that the separator does end the chunk:
a = [0, 0, -1, 1, -1, 1] e = a.chunk{|i| i < 0 ? :_separator : true } e.to_a # => [[true, [0, 0]], [true, [1]], [true, [1]]]
For example, the sequence of hyphens in svn log can be eliminated as follows:
sep = "-"*72 + "\n" IO.popen("svn log README") { |f| f.chunk { |line| line != sep || nil }.each { |_, lines| pp lines } } #=> ["r20018 | knu | 2008-10-29 13:20:42 +0900 (Wed, 29 Oct 2008) | 2 lines\n", # "\n", # "* README, README.ja: Update the portability section.\n", # "\n"] # ["r16725 | knu | 2008-05-31 23:34:23 +0900 (Sat, 31 May 2008) | 2 lines\n", # "\n", # "* README, README.ja: Add a note about default C flags.\n", # "\n"] # ...
Paragraphs separated by empty lines can be parsed as follows:
File.foreach("README").chunk { |line| /\A\s*\z/ !~ line || nil }.each { |_, lines| pp lines }
Returns an enumerator object generated from this enumerator and given enumerables.
e = (1..3).chain([4, 5]) e.to_a #=> [1, 2, 3, 4, 5]
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 the state of the coverage measurement.
Allocate size bytes of memory and return the integer memory address for the allocated memory.
Returns a String containing the generated JSON data.
See also JSON.fast_generate, JSON.pretty_generate.
Argument obj is the Ruby object to be converted to JSON.
Argument opts, if given, contains a Hash of options for the generation. See Generating Options.
When obj is an Array, returns a String containing a JSON array:
obj = ["foo", 1.0, true, false, nil] json = JSON.generate(obj) json # => '["foo",1.0,true,false,null]'
When obj is a Hash, returns a String containing a JSON object:
obj = {foo: 0, bar: 's', baz: :bat} json = JSON.generate(obj) json # => '{"foo":0,"bar":"s","baz":"bat"}'
For examples of generating from other Ruby objects, see Generating JSON from Other Objects.
Raises an exception if any formatting option is not a String.
Raises an exception if obj contains circular references:
a = []; b = []; a.push(b); b.push(a) # Raises JSON::NestingError (nesting of 100 is too deep): JSON.generate(a)
Checks the status of the child process specified by pid. Returns nil if the process is still alive.
If the process is not alive, and raise was true, a PTY::ChildExited exception will be raised. Otherwise it will return a Process::Status instance.
pid
The process id of the process to check
raise
If true and the process identified by pid is no longer alive a PTY::ChildExited is raised.
Returns the log priority mask in effect. The mask is not reset by opening or closing syslog.
Sets the log priority mask. A method LOG_UPTO is defined to make it easier to set mask values. Example:
Syslog.mask = Syslog::LOG_UPTO(Syslog::LOG_ERR)
Alternatively, specific priorities can be selected and added together using binary OR. Example:
Syslog.mask = Syslog::LOG_MASK(Syslog::LOG_ERR) | Syslog::LOG_MASK(Syslog::LOG_CRIT)
The priority mask persists through calls to open() and close().
Compresses the given string. Valid values of level are Zlib::NO_COMPRESSION, Zlib::BEST_SPEED, Zlib::BEST_COMPRESSION, Zlib::DEFAULT_COMPRESSION, or an integer from 0 to 9.
This method is almost equivalent to the following code:
def deflate(string, level) z = Zlib::Deflate.new(level) dst = z.deflate(string, Zlib::FINISH) z.close dst end
See also Zlib.inflate
Decompresses string. Raises a Zlib::NeedDict exception if a preset dictionary is needed for decompression.
This method is almost equivalent to the following code:
def inflate(string) zstream = Zlib::Inflate.new buf = zstream.inflate(string) zstream.finish zstream.close buf end
See also Zlib.deflate
Returns true if the named file is a character device.
file_name can be an IO object.
Returns a Hash containing information about the GC.
The contents of the hash are implementation specific and may change in the future without notice.
The hash includes information about internal statistics about GC such as:
The total number of garbage collections ran since application start (count includes both minor and major garbage collections)
The total number of ‘:heap_eden_pages` + `:heap_tomb_pages`
The number of pages that can fit into the buffer that holds references to all pages
The total number of pages the application could allocate without additional GC
The total number of slots in all ‘:heap_allocated_pages`
The total number of slots which contain live objects
The total number of slots which do not contain live objects
The total number of slots with pending finalizers to be run
The total number of objects marked in the last GC
The total number of pages which contain at least one live slot
The total number of pages which do not contain any live slots
The cumulative number of pages allocated since application start
The cumulative number of pages freed since application start
The cumulative number of objects allocated since application start
The cumulative number of objects freed since application start
Amount of memory allocated on the heap for objects. Decreased by any GC
When ‘:malloc_increase_bytes` crosses this limit, GC is triggered
The total number of minor garbage collections run since process start
The total number of major garbage collections run since process start
The total number of objects without write barriers
When ‘:remembered_wb_unprotected_objects` crosses this limit, major GC is triggered
Number of live, old objects which have survived at least 3 garbage collections
When ‘:old_objects` crosses this limit, major GC is triggered
Amount of memory allocated on the heap for objects. Decreased by major GC
When ‘:old_malloc_increase_bytes` crosses this limit, major GC is triggered
If the optional argument, hash, is given, it is overwritten and returned. This is intended to avoid probe effect.
This method is only expected to work on CRuby.