Enumerates over the items, chunking them together based on the return value of the block.
Consecutive elements which return the same block value are chunked together.
For example, consecutive even numbers and odd numbers can be chunked as follows.
[3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5].chunk { |n| n.even? }.each { |even, ary| p [even, ary] } #=> [false, [3, 1]] # [true, [4]] # [false, [1, 5, 9]] # [true, [2, 6]] # [false, [5, 3, 5]]
This method is especially useful for sorted series of elements. The following example counts words for each initial letter.
open("/usr/share/dict/words", "r:iso-8859-1") { |f| f.chunk { |line| line.ord }.each { |ch, lines| p [ch.chr, lines.length] } } #=> ["\n", 1] # ["A", 1327] # ["B", 1372] # ["C", 1507] # ["D", 791] # ...
The following key values have special meaning:
nil and :_separator specifies that the elements should be dropped.
:_alone specifies that the element should be chunked by itself.
Any other symbols that begin with an underscore will raise an error:
items.chunk { |item| :_underscore } #=> RuntimeError: symbols beginning with an underscore are reserved
nil and :_separator can be used to ignore some elements.
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 }
:_alone can be used to force items into their own chunk. For example, you can put lines that contain a URL by themselves, and chunk the rest of the lines together, like this:
pattern = /http/ open(filename) { |f| f.chunk { |line| line =~ pattern ? :_alone : true }.each { |key, lines| pp lines } }
If no block is given, an enumerator to ‘chunk` is returned instead.
Returns system configuration directory.
This is typically “/etc”, but is modified by the prefix used when Ruby was compiled. For example, if Ruby is built and installed in /usr/local, returns “/usr/local/etc” on other platforms than Windows. On Windows, this always returns the directory provided by the system.
Returns system temporary directory; typically “/tmp”.
Returns system configuration variable using sysconf().
name should be a constant under Etc which begins with SC_.
The return value is an integer or nil. nil means indefinite limit. (sysconf() returns -1 but errno is not set.)
Etc.sysconf(Etc::SC_ARG_MAX) #=> 2097152 Etc.sysconf(Etc::SC_LOGIN_NAME_MAX) #=> 256
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.
pidThe process id of the process to check
raiseIf true and the process identified by pid is no longer alive a PTY::ChildExited is raised.
Returns true if the named file is a symbolic link.
Returns true if the named file is a character device.
file_name can be an IO object.
Invokes the block with a Benchmark::Report object, which may be used to collect and report on the results of individual benchmark tests. Reserves label_width leading spaces for labels on each line. Prints caption at the top of the report, and uses format to format each line. Returns an array of Benchmark::Tms objects.
If the block returns an array of Benchmark::Tms objects, these will be used to format additional lines of output. If labels parameter are given, these are used to label these extra lines.
Note: Other methods provide a simpler interface to this one, and are suitable for nearly all benchmarking requirements. See the examples in Benchmark, and the bm and bmbm methods.
Example:
require 'benchmark' include Benchmark # we need the CAPTION and FORMAT constants n = 5000000 Benchmark.benchmark(CAPTION, 7, FORMAT, ">total:", ">avg:") do |x| tf = x.report("for:") { for i in 1..n; a = "1"; end } tt = x.report("times:") { n.times do ; a = "1"; end } tu = x.report("upto:") { 1.upto(n) do ; a = "1"; end } [tf+tt+tu, (tf+tt+tu)/3] end
Generates:
user system total real for: 0.970000 0.000000 0.970000 ( 0.970493) times: 0.990000 0.000000 0.990000 ( 0.989542) upto: 0.970000 0.000000 0.970000 ( 0.972854) >total: 2.930000 0.000000 2.930000 ( 2.932889) >avg: 0.976667 0.000000 0.976667 ( 0.977630)
Invokes the block with a Benchmark::Report object, which may be used to collect and report on the results of individual benchmark tests. Reserves label_width leading spaces for labels on each line. Prints caption at the top of the report, and uses format to format each line. Returns an array of Benchmark::Tms objects.
If the block returns an array of Benchmark::Tms objects, these will be used to format additional lines of output. If labels parameter are given, these are used to label these extra lines.
Note: Other methods provide a simpler interface to this one, and are suitable for nearly all benchmarking requirements. See the examples in Benchmark, and the bm and bmbm methods.
Example:
require 'benchmark' include Benchmark # we need the CAPTION and FORMAT constants n = 5000000 Benchmark.benchmark(CAPTION, 7, FORMAT, ">total:", ">avg:") do |x| tf = x.report("for:") { for i in 1..n; a = "1"; end } tt = x.report("times:") { n.times do ; a = "1"; end } tu = x.report("upto:") { 1.upto(n) do ; a = "1"; end } [tf+tt+tu, (tf+tt+tu)/3] end
Generates:
user system total real for: 0.970000 0.000000 0.970000 ( 0.970493) times: 0.990000 0.000000 0.990000 ( 0.989542) upto: 0.970000 0.000000 0.970000 ( 0.972854) >total: 2.930000 0.000000 2.930000 ( 2.932889) >avg: 0.976667 0.000000 0.976667 ( 0.977630)
Changes permission bits on the named files (in list) to the bit pattern represented by mode.
mode is the symbolic and absolute mode can be used.
Absolute mode is
FileUtils.chmod 0755, 'somecommand' FileUtils.chmod 0644, %w(my.rb your.rb his.rb her.rb) FileUtils.chmod 0755, '/usr/bin/ruby', :verbose => true
Symbolic mode is
FileUtils.chmod "u=wrx,go=rx", 'somecommand' FileUtils.chmod "u=wr,go=rr", %w(my.rb your.rb his.rb her.rb) FileUtils.chmod "u=wrx,go=rx", '/usr/bin/ruby', :verbose => true
is user, group, other mask.
is user’s mask.
is group’s mask.
is other’s mask.
is write permission.
is read permission.
is execute permission.
is execute permission for directories only, must be used in conjunction with “+”
is uid, gid.
is sticky bit.
is added to a class given the specified mode.
Is removed from a given class given mode.
Is the exact nature of the class will be given a specified mode.
Changes permission bits on the named files (in list) to the bit pattern represented by mode.
mode is the symbolic and absolute mode can be used.
Absolute mode is
FileUtils.chmod 0755, 'somecommand' FileUtils.chmod 0644, %w(my.rb your.rb his.rb her.rb) FileUtils.chmod 0755, '/usr/bin/ruby', :verbose => true
Symbolic mode is
FileUtils.chmod "u=wrx,go=rx", 'somecommand' FileUtils.chmod "u=wr,go=rr", %w(my.rb your.rb his.rb her.rb) FileUtils.chmod "u=wrx,go=rx", '/usr/bin/ruby', :verbose => true
is user, group, other mask.
is user’s mask.
is group’s mask.
is other’s mask.
is write permission.
is read permission.
is execute permission.
is execute permission for directories only, must be used in conjunction with “+”
is uid, gid.
is sticky bit.
is added to a class given the specified mode.
Is removed from a given class given mode.
Is the exact nature of the class will be given a specified mode.
Changes permission bits on the named files (in list) to the bit pattern represented by mode.
FileUtils.chmod_R 0700, "/tmp/app.#{$$}" FileUtils.chmod_R "u=wrx", "/tmp/app.#{$$}"
Changes permission bits on the named files (in list) to the bit pattern represented by mode.
FileUtils.chmod_R 0700, "/tmp/app.#{$$}" FileUtils.chmod_R "u=wrx", "/tmp/app.#{$$}"
Changes owner and group on the named files (in list) to the user user and the group group. user and group may be an ID (Integer/String) or a name (String). If user or group is nil, this method does not change the attribute.
FileUtils.chown 'root', 'staff', '/usr/local/bin/ruby' FileUtils.chown nil, 'bin', Dir.glob('/usr/bin/*'), :verbose => true
Changes owner and group on the named files (in list) to the user user and the group group. user and group may be an ID (Integer/String) or a name (String). If user or group is nil, this method does not change the attribute.
FileUtils.chown 'root', 'staff', '/usr/local/bin/ruby' FileUtils.chown nil, 'bin', Dir.glob('/usr/bin/*'), :verbose => true
Changes owner and group on the named files (in list) to the user user and the group group recursively. user and group may be an ID (Integer/String) or a name (String). If user or group is nil, this method does not change the attribute.
FileUtils.chown_R 'www', 'www', '/var/www/htdocs' FileUtils.chown_R 'cvs', 'cvs', '/var/cvs', :verbose => true
Changes owner and group on the named files (in list) to the user user and the group group recursively. user and group may be an ID (Integer/String) or a name (String). If user or group is nil, this method does not change the attribute.
FileUtils.chown_R 'www', 'www', '/var/www/htdocs' FileUtils.chown_R 'cvs', 'cvs', '/var/cvs', :verbose => true
Updates modification time (mtime) and access time (atime) of file(s) in list. Files are created if they don’t exist.
FileUtils.touch 'timestamp' FileUtils.touch Dir.glob('*.c'); system 'make'
Updates modification time (mtime) and access time (atime) of file(s) in list. Files are created if they don’t exist.
FileUtils.touch 'timestamp' FileUtils.touch Dir.glob('*.c'); system 'make'
Set the changed state of this object. Notifications will be sent only if the changed state is true.
stateBoolean indicating the changed state of this Observable.
Returns true if this object’s state has been changed since the last notify_observers call.