Returns a canonical string representation of time.
Time.now.asctime #=> "Wed Apr 9 08:56:03 2003" Time.now.ctime #=> "Wed Apr 9 08:56:03 2003"
Returns the month of the year (1..12) for time.
t = Time.now #=> 2007-11-19 08:27:30 -0600 t.mon #=> 11 t.month #=> 11
Returns true if time represents Thursday.
t = Time.local(1995, 12, 21) #=> 1995-12-21 00:00:00 -0600 p t.thursday? #=> true
Returns true if time represents Saturday.
t = Time.local(2006, 6, 10) #=> 2006-06-10 00:00:00 -0500 t.saturday? #=> true
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 08:37AM"
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 number of entries in the database.
Updates the database with multiple values from the specified object. Takes any object which implements the each_pair method, including Hash and DBM objects.
Returns true if the database contains the specified key, false otherwise.
Returns the number of struct members.
Customer = Struct.new(:name, :address, :zip) joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345) joe.length #=> 3
Returns the struct members as an array of symbols:
Customer = Struct.new(:name, :address, :zip) joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345) joe.members #=> [:name, :address, :zip]
Reads and returns a line without echo back. Prints prompt unless it is nil.
You must require ‘io/console’ to use this method.
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
Immediately writes all buffered data in ios to disk.
If the underlying operating system does not support fdatasync(2), IO#fsync is called instead (which might raise a NotImplementedError).
Reads at most maxlen bytes from the I/O stream. It blocks only if ios has no data immediately available. It doesn’t block if some data available.
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.
It raises EOFError on end of file.
readpartial is designed for streams such as pipe, socket, tty, etc. It blocks only when no data immediately available. This means that it blocks only when following all conditions hold.
the byte buffer in the IO object is empty.
the content of the stream is empty.
the stream is not reached to EOF.
When readpartial blocks, it waits data or EOF on the stream. If some data is reached, readpartial returns with the data. If EOF is reached, readpartial raises EOFError.
When readpartial doesn’t blocks, it returns or raises immediately. If the byte buffer is not empty, it returns the data in the buffer. Otherwise if the stream has some content, it returns the data in the stream. Otherwise if the stream is reached to EOF, it raises EOFError.
r, w = IO.pipe # buffer pipe content w << "abc" # "" "abc". r.readpartial(4096) #=> "abc" "" "" r.readpartial(4096) # blocks because buffer and pipe is empty. r, w = IO.pipe # buffer pipe content w << "abc" # "" "abc" w.close # "" "abc" EOF r.readpartial(4096) #=> "abc" "" EOF r.readpartial(4096) # raises EOFError r, w = IO.pipe # buffer pipe content 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" "" ""
Note that readpartial behaves 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 retry the system call.
The latter means that readpartial is nonblocking-flag insensitive. It blocks on the situation IO#sysread causes Errno::EWOULDBLOCK as if the fd is blocking mode.
Returns true if ios is associated with a terminal device (tty), false otherwise.
File.new("testfile").isatty #=> false File.new("/dev/tty").isatty #=> true
Returns the number of key-value pairs in this database.
Adds the key-value pairs of other to gdbm, overwriting entries with duplicate keys with those from other. other must have an each_pair method.
Returns true if the given key k exists within the database. Returns false otherwise.
Returns true if obj is an element of the range, false otherwise. If begin and end are numeric, comparison is done according to the magnitude of the values.
("a".."z").include?("g") #=> true ("a".."z").include?("A") #=> false ("a".."z").include?("cc") #=> false
Returns a MatchData object describing the match, or nil if there was no match. This is equivalent to retrieving the value of the special variable $~ following a normal match. If the second parameter is present, it specifies the position in the string to begin the search.
/(.)(.)(.)/.match("abc")[2] #=> "b" /(.)(.)/.match("abc", 1)[2] #=> "c"
If a block is given, invoke the block with MatchData if match succeed, so that you can write
/M(.*)/.match("Matz") do |m| puts m[0] puts m[1] end
instead of
if m = /M(.*)/.match("Matz") puts m[0] puts m[1] end
The return value is a value from block execution in this case.
Returns a true or false indicates whether the regexp is matched or not without updating $~ and other related variables. If the second parameter is present, it specifies the position in the string to begin the search.
/R.../.match?("Ruby") #=> true /R.../.match?("Ruby", 1) #=> false /P.../.match?("Ruby") #=> false $& #=> nil
Same as sym.to_s.length.
Returns sym.to_s.match.
Returns sym.to_s.match?.
Allocates space for a new object of class’s class and does not call initialize on the new instance. The returned object must be an instance of class.
klass = Class.new do def initialize(*args) @initialized = true end def initialized? @initialized || false end end klass.allocate.initialized? #=> false