Method: Time#strftime
- Defined in:
- time.c
#strftime(string) ⇒ String
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)
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# File 'time.c', line 5071
static VALUE
time_strftime(VALUE time, VALUE format)
{
struct time_object *tobj;
const char *fmt;
long len;
rb_encoding *enc;
VALUE tmp;
GetTimeval(time, tobj);
MAKE_TM_ENSURE(time, tobj, tobj->vtm.yday != 0);
StringValue(format);
if (!rb_enc_str_asciicompat_p(format)) {
rb_raise(rb_eArgError, "format should have ASCII compatible encoding");
}
tmp = rb_str_tmp_frozen_acquire(format);
fmt = RSTRING_PTR(tmp);
len = RSTRING_LEN(tmp);
enc = rb_enc_get(format);
if (len == 0) {
rb_warning("strftime called with empty format string");
return rb_enc_str_new(0, 0, enc);
}
else {
VALUE str = rb_strftime_alloc(fmt, len, enc, time, &tobj->vtm, tobj->timew,
TZMODE_UTC_P(tobj));
rb_str_tmp_frozen_release(format, tmp);
if (!str) rb_raise(rb_eArgError, "invalid format: %"PRIsVALUE, format);
return str;
}
}
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