Returns a 2-element Array containing the name and value of the environment variable for name if it exists:
ENV.replace('foo' => '0', 'bar' => '1') ENV.assoc('foo') # => ['foo', '0']
Returns nil if name is a valid String and there is no such environment variable.
Returns nil if name is the empty String or is a String containing character '='.
Raises an exception if name is a String containing the NUL character "\0":
ENV.assoc("\0") # Raises ArgumentError (bad environment variable name: contains null byte)
Raises an exception if name has an encoding that is not ASCII-compatible:
ENV.assoc("\xa1\xa1".force_encoding(Encoding::UTF_16LE)) # Raises ArgumentError (bad environment variable name: ASCII incompatible encoding: UTF-16LE)
Raises an exception if name is not a String:
ENV.assoc(Object.new) # TypeError (no implicit conversion of Object into String)
Returns a 2-element Array containing the name and value of the first found environment variable that has value value, if one exists:
ENV.replace('foo' => '0', 'bar' => '0') ENV.rassoc('0') # => ["bar", "0"]
The order in which environment variables are examined is OS-dependent. See About Ordering.
Returns nil if there is no such environment variable.
Writes the given objects to the stream; returns nil. Appends the output record separator $OUTPUT_RECORD_SEPARATOR ($\), if it is not nil. See Line IO.
With argument objects given, for each object:
Converts via its method to_s if not a string.
Writes to the stream.
If not the last object, writes the output field separator $OUTPUT_FIELD_SEPARATOR ($,) if it is not nil.
With default separators:
f = File.open('t.tmp', 'w+') objects = [0, 0.0, Rational(0, 1), Complex(0, 0), :zero, 'zero'] p $OUTPUT_RECORD_SEPARATOR p $OUTPUT_FIELD_SEPARATOR f.print(*objects) f.rewind p f.read f.close
Output:
nil nil "00.00/10+0izerozero"
With specified separators:
$\ = "\n" $, = ',' f.rewind f.print(*objects) f.rewind p f.read
Output:
"0,0.0,0/1,0+0i,zero,zero\n"
With no argument given, writes the content of $_ (which is usually the most recent user input):
f = File.open('t.tmp', 'w+') gets # Sets $_ to the most recent user input. f.print f.close
Formats and writes objects to the stream.
For details on format_string, see Format Specifications.
Sets optional filename and line number that will be used in ERB code evaluation and error reporting. See also filename= and lineno=
erb = ERB.new('<%= some_x %>') erb.render # undefined local variable or method `some_x' # from (erb):1 erb.location = ['file.erb', 3] # All subsequent error reporting would use new location erb.render # undefined local variable or method `some_x' # from file.erb:4
Returns true if the ipaddr is a private address. IPv4 addresses in 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 as defined in RFC 1918 and IPv6 Unique Local Addresses in fc00::/7 as defined in RFC 4193 are considered private. Private IPv4 addresses in the IPv4-mapped IPv6 address range are also considered private.
Returns the prefix length in bits for the ipaddr.
Sets the prefix length in bits
Parses environment variable env or its uppercase with splitting like a shell.
env defaults to the basename of the program.
Groups line break hints added in the block. The line break hints are all to be used or not.
If indent is specified, the method call is regarded as nested by nest(indent) { … }.
If open_obj is specified, text open_obj, open_width is called before grouping. If close_obj is specified, text close_obj, close_width is called after grouping.
Returns the priority of thr. Default is inherited from the current thread which creating the new thread, or zero for the initial main thread; higher-priority thread will run more frequently than lower-priority threads (but lower-priority threads can also run).
This is just hint for Ruby thread scheduler. It may be ignored on some platform.
Thread.current.priority #=> 0
Sets the priority of thr to integer. Higher-priority threads will run more frequently than lower-priority threads (but lower-priority threads can also run).
This is just hint for Ruby thread scheduler. It may be ignored on some platform.
count1 = count2 = 0 a = Thread.new do loop { count1 += 1 } end a.priority = -1 b = Thread.new do loop { count2 += 1 } end b.priority = -2 sleep 1 #=> 1 count1 #=> 622504 count2 #=> 5832
Returns the ThreadGroup which contains the given thread.
Thread.main.group #=> #<ThreadGroup:0x4029d914>
Equivalent to:
io.write(sprintf(format_string, *objects))
For details on format_string, see Format Specifications.
With the single argument format_string, formats objects into the string, then writes the formatted string to $stdout:
printf('%4.4d %10s %2.2f', 24, 24, 24.0)
Output (on $stdout):
0024 24 24.00#
With arguments io and format_string, formats objects into the string, then writes the formatted string to io:
printf($stderr, '%4.4d %10s %2.2f', 24, 24, 24.0)
Output (on $stderr):
0024 24 24.00# => nil
With no arguments, does nothing.
Equivalent to $stdout.print(*objects), this method is the straightforward way to write to $stdout.
Writes the given objects to $stdout; returns nil. Appends the output record separator $OUTPUT_RECORD_SEPARATOR $\), if it is not nil.
With argument objects given, for each object:
Converts via its method to_s if not a string.
Writes to stdout.
If not the last object, writes the output field separator $OUTPUT_FIELD_SEPARATOR ($, if it is not nil.
With default separators:
objects = [0, 0.0, Rational(0, 1), Complex(0, 0), :zero, 'zero'] $OUTPUT_RECORD_SEPARATOR $OUTPUT_FIELD_SEPARATOR print(*objects)
Output:
nil nil 00.00/10+0izerozero
With specified separators:
$OUTPUT_RECORD_SEPARATOR = "\n" $OUTPUT_FIELD_SEPARATOR = ',' print(*objects)
Output:
0,0.0,0/1,0+0i,zero,zero
With no argument given, writes the content of $_ (which is usually the most recent user input):
gets # Sets $_ to the most recent user input. print # Prints $_.
Returns the freeze status of obj.
a = [ "a", "b", "c" ] a.freeze #=> ["a", "b", "c"] a.frozen? #=> true
Returns the string resulting from formatting objects into format_string.
For details on format_string, see Format Specifications.
Transfers control to the end of the active catch block waiting for tag. Raises UncaughtThrowError if there is no catch block for the tag. The optional second parameter supplies a return value for the catch block, which otherwise defaults to nil. For examples, see Kernel::catch.
For positive integer n, returns an array containing all but the first n elements:
r = (1..4) r.drop(3) # => [4] r.drop(2) # => [3, 4] r.drop(1) # => [2, 3, 4] r.drop(0) # => [1, 2, 3, 4] r.drop(50) # => [] h = {foo: 0, bar: 1, baz: 2, bat: 3} h.drop(2) # => [[:baz, 2], [:bat, 3]]
Provides a convenient Ruby iterator which executes a block for each entry in the /etc/group file.
The code block is passed an Group struct.
See ::getgrent above for details.
Example:
require 'etc' Etc.group {|g| puts g.name + ": " + g.mem.join(', ') }
See any remaining errors held in queue.
Any errors you see here are probably due to a bug in Ruby’s OpenSSL implementation.
Returns true if the named file exists and has a zero size.
file_name can be an IO object.
Returns true if filepath points to a socket, false otherwise:
require 'socket' File.socket?(Socket.new(:INET, :STREAM)) # => true File.socket?(File.new('t.txt')) # => false
Returns true if filepath points to a block device, false otherwise:
File.blockdev?('/dev/sda1') # => true File.blockdev?(File.new('t.tmp')) # => false