Returns the first element, or the first n elements, of the enumerable. If the enumerable is empty, the first form returns nil, and the second form returns an empty array.
%w[foo bar baz].first #=> "foo" %w[foo bar baz].first(2) #=> ["foo", "bar"] %w[foo bar baz].first(10) #=> ["foo", "bar", "baz"] [].first #=> nil [].first(10) #=> []
Passes each element of the collection to the given block. The method returns true if the block returns true exactly once. If the block is not given, one? will return true only if exactly one of the collection members is true.
If instead a pattern is supplied, the method returns whether pattern === element for exactly one collection member.
%w{ant bear cat}.one? { |word| word.length == 4 } #=> true %w{ant bear cat}.one? { |word| word.length > 4 } #=> false %w{ant bear cat}.one? { |word| word.length < 4 } #=> false %w{ant bear cat}.one?(/t/) #=> false [ nil, true, 99 ].one? #=> false [ nil, true, false ].one? #=> true [ nil, true, 99 ].one?(Integer) #=> true [].one? #=> false
Passes each element of the collection to the given block. The method returns true if the block never returns true for all elements. If the block is not given, none? will return true only if none of the collection members is true.
If instead a pattern is supplied, the method returns whether pattern === element for none of the collection members.
%w{ant bear cat}.none? { |word| word.length == 5 } #=> true %w{ant bear cat}.none? { |word| word.length >= 4 } #=> false %w{ant bear cat}.none?(/d/) #=> true [1, 3.14, 42].none?(Float) #=> false [].none? #=> true [nil].none? #=> true [nil, false].none? #=> true [nil, false, true].none? #=> false
Returns true if any member of enum equals obj. Equality is tested using ==.
IO.constants.include? :SEEK_SET #=> true IO.constants.include? :SEEK_NO_FURTHER #=> false IO.constants.member? :SEEK_SET #=> true IO.constants.member? :SEEK_NO_FURTHER #=> false
Drops first n elements from enum, and returns rest elements in an array.
a = [1, 2, 3, 4, 5, 0] a.drop(3) #=> [4, 5, 0]
Writes warning message msg to $stderr. This method is called by Ruby for all emitted warnings.
Determines the equality of two numbers by comparing to zero, or using the epsilon value
Enables coverage measurement.
Resets the process of reading the /etc/passwd file, so that the next call to ::getpwent will return the first entry again.
Provides a convenient Ruby iterator which executes a block for each entry in the /etc/passwd file.
The code block is passed an Passwd struct.
See ::getpwent above for details.
Example:
require 'etc' Etc.passwd {|u| puts u.name + " = " + u.gecos }
Resets the process of reading the /etc/group file, so that the next call to ::getgrent will return the first entry again.
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 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
Returns system configuration variable using confstr().
name should be a constant under Etc which begins with CS_.
The return value is a string or nil. nil means no configuration-defined value. (confstr() returns 0 but errno is not set.)
Etc.confstr(Etc::CS_PATH) #=> "/bin:/usr/bin" # GNU/Linux Etc.confstr(Etc::CS_GNU_LIBC_VERSION) #=> "glibc 2.18" Etc.confstr(Etc::CS_GNU_LIBPTHREAD_VERSION) #=> "NPTL 2.18"
Creates a new handler that opens library, and returns an instance of Fiddle::Handle.
If nil is given for the library, Fiddle::Handle::DEFAULT is used, which is the equivalent to RTLD_DEFAULT. See man 3 dlopen for more.
lib = Fiddle.dlopen(nil)
The default is dependent on OS, and provide a handle for all libraries already loaded. For example, in most cases you can use this to access libc functions, or ruby functions like rb_str_new.
See Fiddle::Handle.new for more.
Creates a new handler that opens library, and returns an instance of Fiddle::Handle.
If nil is given for the library, Fiddle::Handle::DEFAULT is used, which is the equivalent to RTLD_DEFAULT. See man 3 dlopen for more.
lib = Fiddle.dlopen(nil)
The default is dependent on OS, and provide a handle for all libraries already loaded. For example, in most cases you can use this to access libc functions, or ruby functions like rb_str_new.
See Fiddle::Handle.new for more.
Generate a JSON document from the Ruby data structure obj and return it. state is * a JSON::State object,
or a Hash like object (responding to to_hash),
an object convertible into a hash by a to_h method,
that is used as or to configure a State object.
It defaults to a state object, that creates the shortest possible JSON text in one line, checks for circular data structures and doesn’t allow NaN, Infinity, and -Infinity.
A state hash can have the following keys:
indent: a string used to indent levels (default: ”),
space: a string that is put after, a : or , delimiter (default: ”),
space_before: a string that is put before a : pair delimiter (default: ”),
object_nl: a string that is put at the end of a JSON object (default: ”),
array_nl: a string that is put at the end of a JSON array (default: ”),
allow_nan: true if NaN, Infinity, and -Infinity should be generated, otherwise an exception is thrown if these values are encountered. This options defaults to false.
max_nesting: The maximum depth of nesting allowed in the data structures from which JSON is to be generated. Disable depth checking with :max_nesting => false, it defaults to 100.
See also the fast_generate for the fastest creation method with the least amount of sanity checks, and the pretty_generate method for some defaults for pretty output.
Encodes string using Ruby’s String.encode
Returns whether input encoding is EUC-JP or not.
Note don’t expect this return value is MatchData.
Returns whether input encoding is EUC-JP or not.
Note don’t expect this return value is MatchData.
Spawns the specified command on a newly allocated pty. You can also use the alias ::getpty.
The command’s controlling tty is set to the slave device of the pty and its standard input/output/error is redirected to the slave device.
command and command_line are the full commands to run, given a String. Any additional arguments will be passed to the command.
In the non-block form this returns an array of size three, [r, w, pid].
In the block form these same values will be yielded to the block:
Spawns the specified command on a newly allocated pty. You can also use the alias ::getpty.
The command’s controlling tty is set to the slave device of the pty and its standard input/output/error is redirected to the slave device.
command and command_line are the full commands to run, given a String. Any additional arguments will be passed to the command.
In the non-block form this returns an array of size three, [r, w, pid].
In the block form these same values will be yielded to the block:
Allocates a pty (pseudo-terminal).
In the block form, yields two arguments master_io, slave_file and the value of the block is returned from open.
The IO and File are both closed after the block completes if they haven’t been already closed.
PTY.open {|master, slave| p master #=> #<IO:masterpty:/dev/pts/1> p slave #=> #<File:/dev/pts/1> p slave.path #=> "/dev/pts/1" }
In the non-block form, returns a two element array, [master_io, slave_file].
master, slave = PTY.open # do something with master for IO, or the slave file
The arguments in both forms are:
master_io
the master of the pty, as an IO.
slave_file
the slave of the pty, as a File. The path to the terminal device is available via slave_file.path
IO#raw! is usable to disable newline conversions:
require 'io/console'
PTY.open {|m, s|
s.raw!
...
}