Returns true if time occurs during Daylight Saving Time in its time zone.
# CST6CDT: Time.local(2000, 1, 1).zone #=> "CST" Time.local(2000, 1, 1).isdst #=> false Time.local(2000, 1, 1).dst? #=> false Time.local(2000, 7, 1).zone #=> "CDT" Time.local(2000, 7, 1).isdst #=> true Time.local(2000, 7, 1).dst? #=> true # Asia/Tokyo: Time.local(2000, 1, 1).zone #=> "JST" Time.local(2000, 1, 1).isdst #=> false Time.local(2000, 1, 1).dst? #=> false Time.local(2000, 7, 1).zone #=> "JST" Time.local(2000, 7, 1).isdst #=> false Time.local(2000, 7, 1).dst? #=> false
Returns true if time occurs during Daylight Saving Time in its time zone.
# CST6CDT: Time.local(2000, 1, 1).zone #=> "CST" Time.local(2000, 1, 1).isdst #=> false Time.local(2000, 1, 1).dst? #=> false Time.local(2000, 7, 1).zone #=> "CDT" Time.local(2000, 7, 1).isdst #=> true Time.local(2000, 7, 1).dst? #=> true # Asia/Tokyo: Time.local(2000, 1, 1).zone #=> "JST" Time.local(2000, 1, 1).isdst #=> false Time.local(2000, 1, 1).dst? #=> false Time.local(2000, 7, 1).zone #=> "JST" Time.local(2000, 7, 1).isdst #=> false Time.local(2000, 7, 1).dst? #=> false
Returns the offset in seconds between the timezone of time and UTC.
t = Time.gm(2000,1,1,20,15,1) #=> 2000-01-01 20:15:01 UTC t.gmt_offset #=> 0 l = t.getlocal #=> 2000-01-01 14:15:01 -0600 l.gmt_offset #=> -21600
Formats time according to the directives in the given format string.
The directives begin with a percent (%) character. Any text not listed as a directive will be passed through to the output string.
The directive consists of a percent (%) character, zero or more flags, optional minimum field width, optional modifier and a conversion specifier as follows:
%<flags><width><modifier><conversion>
Flags:
- don't pad a numerical output _ use spaces for padding 0 use zeros for padding ^ upcase the result string # change case : use colons for %z
The minimum field width specifies the minimum width.
The modifiers are “E” and “O”. They are ignored.
Format directives:
Date (Year, Month, Day):
%Y - Year with century if provided, will pad result at least 4 digits.
-0001, 0000, 1995, 2009, 14292, etc.
%C - year / 100 (rounded down such as 20 in 2009)
%y - year % 100 (00..99)
%m - Month of the year, zero-padded (01..12)
%_m blank-padded ( 1..12)
%-m no-padded (1..12)
%B - The full month name (``January'')
%^B uppercased (``JANUARY'')
%b - The abbreviated month name (``Jan'')
%^b uppercased (``JAN'')
%h - Equivalent to %b
%d - Day of the month, zero-padded (01..31)
%-d no-padded (1..31)
%e - Day of the month, blank-padded ( 1..31)
%j - Day of the year (001..366)
Time (Hour, Minute, Second, Subsecond):
%H - Hour of the day, 24-hour clock, zero-padded (00..23)
%k - Hour of the day, 24-hour clock, blank-padded ( 0..23)
%I - Hour of the day, 12-hour clock, zero-padded (01..12)
%l - Hour of the day, 12-hour clock, blank-padded ( 1..12)
%P - Meridian indicator, lowercase (``am'' or ``pm'')
%p - Meridian indicator, uppercase (``AM'' or ``PM'')
%M - Minute of the hour (00..59)
%S - Second of the minute (00..60)
%L - Millisecond of the second (000..999)
The digits under millisecond are truncated to not produce 1000.
%N - Fractional seconds digits, default is 9 digits (nanosecond)
%3N millisecond (3 digits)
%6N microsecond (6 digits)
%9N nanosecond (9 digits)
%12N picosecond (12 digits)
%15N femtosecond (15 digits)
%18N attosecond (18 digits)
%21N zeptosecond (21 digits)
%24N yoctosecond (24 digits)
The digits under the specified length are truncated to avoid
carry up.
Time zone:
%z - Time zone as hour and minute offset from UTC (e.g. +0900)
%:z - hour and minute offset from UTC with a colon (e.g. +09:00)
%::z - hour, minute and second offset from UTC (e.g. +09:00:00)
%Z - Abbreviated time zone name or similar information. (OS dependent)
Weekday:
%A - The full weekday name (``Sunday'')
%^A uppercased (``SUNDAY'')
%a - The abbreviated name (``Sun'')
%^a uppercased (``SUN'')
%u - Day of the week (Monday is 1, 1..7)
%w - Day of the week (Sunday is 0, 0..6)
ISO 8601 week-based year and week number:
The first week of YYYY starts with a Monday and includes YYYY-01-04.
The days in the year before the first week are in the last week of
the previous year.
%G - The week-based year
%g - The last 2 digits of the week-based year (00..99)
%V - Week number of the week-based year (01..53)
Week number:
The first week of YYYY that starts with a Sunday or Monday (according to %U
or %W). The days in the year before the first week are in week 0.
%U - Week number of the year. The week starts with Sunday. (00..53)
%W - Week number of the year. The week starts with Monday. (00..53)
Seconds since the Epoch:
%s - Number of seconds since 1970-01-01 00:00:00 UTC.
Literal string:
%n - Newline character (\n)
%t - Tab character (\t)
%% - Literal ``%'' character
Combination:
%c - date and time (%a %b %e %T %Y)
%D - Date (%m/%d/%y)
%F - The ISO 8601 date format (%Y-%m-%d)
%v - VMS date (%e-%^b-%4Y)
%x - Same as %D
%X - Same as %T
%r - 12-hour time (%I:%M:%S %p)
%R - 24-hour time (%H:%M)
%T - 24-hour time (%H:%M:%S)
This method is similar to strftime() function defined in ISO C and POSIX.
While all directives are locale independent since Ruby 1.9, %Z is platform dependent. So, the result may differ even if the same format string is used in other systems such as C.
%z is recommended over %Z. %Z doesn’t identify the timezone. For example, “CST” is used at America/Chicago (-06:00), America/Havana (-05:00), Asia/Harbin (+08:00), Australia/Darwin (+09:30) and Australia/Adelaide (+10:30). Also, %Z is highly dependent on the operating system. For example, it may generate a non ASCII string on Japanese Windows, i.e. the result can be different to “JST”. So the numeric time zone offset, %z, is recommended.
Examples:
t = Time.new(2007,11,19,8,37,48,"-06:00") #=> 2007-11-19 08:37:48 -0600 t.strftime("Printed on %m/%d/%Y") #=> "Printed on 11/19/2007" t.strftime("at %I:%M %p") #=> "at 08:37 AM"
Various ISO 8601 formats:
%Y%m%d => 20071119 Calendar date (basic) %F => 2007-11-19 Calendar date (extended) %Y-%m => 2007-11 Calendar date, reduced accuracy, specific month %Y => 2007 Calendar date, reduced accuracy, specific year %C => 20 Calendar date, reduced accuracy, specific century %Y%j => 2007323 Ordinal date (basic) %Y-%j => 2007-323 Ordinal date (extended) %GW%V%u => 2007W471 Week date (basic) %G-W%V-%u => 2007-W47-1 Week date (extended) %GW%V => 2007W47 Week date, reduced accuracy, specific week (basic) %G-W%V => 2007-W47 Week date, reduced accuracy, specific week (extended) %H%M%S => 083748 Local time (basic) %T => 08:37:48 Local time (extended) %H%M => 0837 Local time, reduced accuracy, specific minute (basic) %H:%M => 08:37 Local time, reduced accuracy, specific minute (extended) %H => 08 Local time, reduced accuracy, specific hour %H%M%S,%L => 083748,000 Local time with decimal fraction, comma as decimal sign (basic) %T,%L => 08:37:48,000 Local time with decimal fraction, comma as decimal sign (extended) %H%M%S.%L => 083748.000 Local time with decimal fraction, full stop as decimal sign (basic) %T.%L => 08:37:48.000 Local time with decimal fraction, full stop as decimal sign (extended) %H%M%S%z => 083748-0600 Local time and the difference from UTC (basic) %T%:z => 08:37:48-06:00 Local time and the difference from UTC (extended) %Y%m%dT%H%M%S%z => 20071119T083748-0600 Date and time of day for calendar date (basic) %FT%T%:z => 2007-11-19T08:37:48-06:00 Date and time of day for calendar date (extended) %Y%jT%H%M%S%z => 2007323T083748-0600 Date and time of day for ordinal date (basic) %Y-%jT%T%:z => 2007-323T08:37:48-06:00 Date and time of day for ordinal date (extended) %GW%V%uT%H%M%S%z => 2007W471T083748-0600 Date and time of day for week date (basic) %G-W%V-%uT%T%:z => 2007-W47-1T08:37:48-06:00 Date and time of day for week date (extended) %Y%m%dT%H%M => 20071119T0837 Calendar date and local time (basic) %FT%R => 2007-11-19T08:37 Calendar date and local time (extended) %Y%jT%H%MZ => 2007323T0837Z Ordinal date and UTC of day (basic) %Y-%jT%RZ => 2007-323T08:37Z Ordinal date and UTC of day (extended) %GW%V%uT%H%M%z => 2007W471T0837-0600 Week date and local time and difference from UTC (basic) %G-W%V-%uT%R%:z => 2007-W47-1T08:37-06:00 Week date and local time and difference from UTC (extended)
Returns the values in self as an array:
Customer = Struct.new(:name, :address, :zip) joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345) joe.to_a # => ["Joe Smith", "123 Maple, Anytown NC", 12345]
Struct#values and Struct#deconstruct are aliases for Struct#to_a.
Related: members.
Returns a hash containing the name and value for each member:
Customer = Struct.new(:name, :address, :zip) joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345) h = joe.to_h h # => {:name=>"Joe Smith", :address=>"123 Maple, Anytown NC", :zip=>12345}
If a block is given, it is called with each name/value pair; the block should return a 2-element array whose elements will become a key/value pair in the returned hash:
h = joe.to_h{|name, value| [name.upcase, value.to_s.upcase]} h # => {:NAME=>"JOE SMITH", :ADDRESS=>"123 MAPLE, ANYTOWN NC", :ZIP=>"12345"}
Raises ArgumentError if the block returns an inappropriate value.
Returns the values in self as an array:
Customer = Struct.new(:name, :address, :zip) joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345) joe.to_a # => ["Joe Smith", "123 Maple, Anytown NC", 12345]
Struct#values and Struct#deconstruct are aliases for Struct#to_a.
Related: members.
Returns a string representation of self:
Customer = Struct.new(:name, :address, :zip) # => Customer joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345) joe.inspect # => "#<struct Customer name=\"Joe Smith\", address=\"123 Maple, Anytown NC\", zip=12345>"
Struct#to_s is an alias for Struct#inspect.
Returns number of bytes that can be read without blocking. Returns zero if no information available.
Returns true if input available without blocking, or false.
Returns status information for ios as an object of type File::Stat.
f = File.new("testfile") s = f.stat "%o" % s.mode #=> "100644" s.blksize #=> 4096 s.atime #=> Wed Apr 09 08:53:54 CDT 2003
Reads the entire file specified by name as individual lines, and returns those lines in an array. Lines are separated by sep.
If name starts with a pipe character ("|") and the receiver is the IO class, a subprocess is created in the same way as Kernel#open, and its output is returned. Consider to use File.readlines to disable the behavior of subprocess invocation.
a = File.readlines("testfile") a[0] #=> "This is line one\n" b = File.readlines("testfile", chomp: true) b[0] #=> "This is line one" IO.readlines("|ls -a") #=> [".\n", "..\n", ...]
If the last argument is a hash, it’s the keyword argument to open.
The options hash accepts the following keys:
When the optional chomp keyword argument has a true value, \n, \r, and \r\n will be removed from the end of each line.
See also IO.read for details about name and open_args.
Opens the file, optionally seeks to the given offset, then returns length bytes (defaulting to the rest of the file). read ensures the file is closed before returning.
If name starts with a pipe character ("|") and the receiver is the IO class, a subprocess is created in the same way as Kernel#open, and its output is returned. Consider to use File.read to disable the behavior of subprocess invocation.
The options hash accepts the following keys:
string or encoding
Specifies the encoding of the read string. :encoding will be ignored if length is specified. See Encoding.aliases for possible encodings.
string or integer
Specifies the mode argument for open(). It must start with an “r”, otherwise it will cause an error. See IO.new for the list of possible modes.
array
Specifies arguments for open() as an array. This key can not be used in combination with either :encoding or :mode.
Examples:
File.read("testfile") #=> "This is line one\nThis is line two\nThis is line three\nAnd so on...\n" File.read("testfile", 20) #=> "This is line one\nThi" File.read("testfile", 20, 10) #=> "ne one\nThis is line " File.read("binfile", mode: "rb") #=> "\xF7\x00\x00\x0E\x12" IO.read("|ls -a") #=> ".\n..\n"...
Opens the file, optionally seeks to the given offset, then returns length bytes (defaulting to the rest of the file). binread ensures the file is closed before returning. The open mode would be "rb:ASCII-8BIT".
If name starts with a pipe character ("|") and the receiver is the IO class, a subprocess is created in the same way as Kernel#open, and its output is returned. Consider to use File.binread to disable the behavior of subprocess invocation.
File.binread("testfile") #=> "This is line one\nThis is line two\nThis is line three\nAnd so on...\n" File.binread("testfile", 20) #=> "This is line one\nThi" File.binread("testfile", 20, 10) #=> "ne one\nThis is line " IO.binread("| cat testfile") #=> "This is line one\nThis is line two\nThis is line three\nAnd so on...\n"
See also IO.read for details about name and open_args.
Reassociates ios with the I/O stream given in other_IO or to a new stream opened on path. This may dynamically change the actual class of this stream. The mode and opt parameters accept the same values as IO.open.
f1 = File.new("testfile") f2 = File.new("testfile") f2.readlines[0] #=> "This is line one\n" f2.reopen(f1) #=> #<File:testfile> f2.readlines[0] #=> "This is line one\n"
Reads maxlen bytes from ios using a low-level read and returns them as a string. Do not mix with other methods that read from ios or you may get unpredictable results.
If the optional outbuf argument is present, it must reference a String, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.
Raises SystemCallError on error and EOFError at end of file.
f = File.new("testfile") f.sysread(16) #=> "This is line one"
Reads maxlen bytes from ios using the pread system call and returns them as a string without modifying the underlying descriptor offset. This is advantageous compared to combining IO#seek and IO#read in that it is atomic, allowing multiple threads/process to share the same IO object for reading the file at various locations. This bypasses any userspace buffering of the IO layer. If the optional outbuf argument is present, it must reference a String, which will receive the data. Raises SystemCallError on error, EOFError at end of file and NotImplementedError if platform does not implement the system call.
File.write("testfile", "This is line one\nThis is line two\n") File.open("testfile") do |f| p f.read # => "This is line one\nThis is line two\n" p f.pread(12, 0) # => "This is line" p f.pread(9, 8) # => "line one\n" end
Reads all of the lines in ios, and returns them in an array. Lines are separated by the optional sep. If sep is nil, the rest of the stream is returned as a single record. If the first argument is an integer, or an optional second argument is given, the returning string would not be longer than the given value in bytes. The stream must be opened for reading or an IOError will be raised.
f = File.new("testfile") f.readlines[0] #=> "This is line one\n" f = File.new("testfile", chomp: true) f.readlines[0] #=> "This is line one"
See IO.readlines for details about getline_args.
Reads up to maxlen bytes from the stream; returns a string (either a new string or the given out_string). Its encoding is:
The unchanged encoding of out_string, if out_string is given.
ASCII-8BIT, otherwise.
Contains maxlen bytes from the stream, if available.
Otherwise contains all available bytes, if any available.
Otherwise is an empty string.
With the single non-negative integer argument maxlen given, returns a new string:
f = File.new('t.txt') f.readpartial(30) # => "This is line one.\nThis is the" f.readpartial(30) # => " second line.\nThis is the thi" f.readpartial(30) # => "rd line.\n" f.eof # => true f.readpartial(30) # Raises EOFError.
With both argument maxlen and string argument out_string given, returns modified out_string:
f = File.new('t.txt') s = 'foo' f.readpartial(30, s) # => "This is line one.\nThis is the" s = 'bar' f.readpartial(0, s) # => ""
This method is useful for a stream such as a pipe, a socket, or a tty. It blocks only when no data is immediately available. This means that it blocks only when all of the following are true:
The byte buffer in the stream is empty.
The content of the stream is empty.
The stream is not at EOF.
When blocked, the method waits for either more data or EOF on the stream:
If more data is read, the method returns the data.
If EOF is reached, the method raises EOFError.
When not blocked, the method responds immediately:
Returns data from the buffer if there is any.
Otherwise returns data from the stream if there is any.
Otherwise raises EOFError if the stream has reached EOF.
Note that this method is similar to sysread. The differences are:
If the byte buffer is not empty, read from the byte buffer instead of “sysread for buffered IO (IOError)”.
It doesn’t cause Errno::EWOULDBLOCK and Errno::EINTR. When readpartial meets EWOULDBLOCK and EINTR by read system call, readpartial retries the system call.
The latter means that readpartial is non-blocking-flag insensitive. It blocks on the situation IO#sysread causes Errno::EWOULDBLOCK as if the fd is blocking mode.
Examples:
# # Returned Buffer Content Pipe Content r, w = IO.pipe # w << 'abc' # "" "abc". r.readpartial(4096) # => "abc" "" "" r.readpartial(4096) # (Blocks because buffer and pipe are empty.) # # Returned Buffer Content Pipe Content r, w = IO.pipe # w << 'abc' # "" "abc" w.close # "" "abc" EOF r.readpartial(4096) # => "abc" "" EOF r.readpartial(4096) # raises EOFError # # Returned Buffer Content Pipe Content r, w = IO.pipe # w << "abc\ndef\n" # "" "abc\ndef\n" r.gets # => "abc\n" "def\n" "" w << "ghi\n" # "def\n" "ghi\n" r.readpartial(4096) # => "def\n" "" "ghi\n" r.readpartial(4096) # => "ghi\n" "" ""
Reads bytes from the stream (in binary mode):
If maxlen is nil, reads all bytes.
Otherwise reads maxlen bytes, if available.
Otherwise reads all bytes.
Returns a string (either a new string or the given out_string) containing the bytes read. The encoding of the string depends on both maxLen and out_string:
maxlen is nil: uses internal encoding of self (regardless of whether out_string was given).
maxlen not nil:
out_string given: encoding of out_string not modified.
out_string not given: ASCII-8BIT is used.
Without Argument out_string
When argument out_string is omitted, the returned value is a new string:
f = File.new('t.txt') f.read # => "This is line one.\nThis is the second line.\nThis is the third line.\n" f.rewind f.read(40) # => "This is line one.\r\nThis is the second li" f.read(40) # => "ne.\r\nThis is the third line.\r\n" f.read(40) # => nil
If maxlen is zero, returns an empty string.
With Argument out_string
When argument out_string is given, the returned value is out_string, whose content is replaced:
f = File.new('t.txt') s = 'foo' # => "foo" f.read(nil, s) # => "This is line one.\nThis is the second line.\nThis is the third line.\n" s # => "This is line one.\nThis is the second line.\nThis is the third line.\n" f.rewind s = 'bar' f.read(40, s) # => "This is line one.\r\nThis is the second li" s # => "This is line one.\r\nThis is the second li" s = 'baz' f.read(40, s) # => "ne.\r\nThis is the third line.\r\n" s # => "ne.\r\nThis is the third line.\r\n" s = 'bat' f.read(40, s) # => nil s # => ""
Note that this method behaves like the fread() function in C. This means it retries to invoke read(2) system calls to read data with the specified maxlen (or until EOF).
This behavior is preserved even if the stream is in non-blocking mode. (This method is non-blocking-flag insensitive as other methods.)
If you need the behavior like a single read(2) system call, consider readpartial, read_nonblock, and sysread.