Date and Time Localization and Formatting
Introduction and Getting Started
ex_cldr_dates_times
is an addon library application for ex_cldr that provides localisation and formatting for dates, times and date_times.
The primary api is Cldr.Date.to_string/2
, Cldr.Time.to_string/2
and Cldr.DateTime.to_string/2
. The following examples demonstrate:
iex> Cldr.Date.to_string Date.utc_today()
{:ok, "Aug 18, 2017"}
iex> Cldr.Time.to_string Time.utc_now
{:ok, "11:38:55 AM"}
iex> Cldr.DateTime.to_string DateTime.utc_now
{:ok, "Aug 18, 2017, 11:39:08 AM"}
iex> Cldr.DateTime.Relative.to_string 1, unit: :day, format: :narrow
{:ok, "tomorrow"}
For help in iex
:
iex> h Cldr.Date.to_string
iex> h Cldr.Time.to_string
iex> h Cldr.DateTime.to_string
iex> h Cldr.DateTime.Relative.to_string
Documentation
Primary documentation is available on as part of the ex_cldr documentation on hex
Format strings
The CLDR standard
defines a wide range of format symbols. Most - but not all - of these symbols are supported in
Cldr
. The supported symbols are described below. Note the known restrictions and limitations.
Element | Symbol | Example | Cldr Format |
---|---|---|---|
Era | G, GG, GGG | “AD” | Abbreviated |
GGGG | “Anno Domini” | Wide | |
GGGGG | “A” | Narrow | |
Year | y | 7 | Minimum necessary digits |
yy | “17” | Least significant 2 digits | |
yyy | “017”, “2017” | Padded to at least 3 digits | |
yyyy | “2017” | Padded to at least 4 digits | |
yyyyy | “02017” | Padded to at least 5 digits | |
ISOWeek Year | Y | 7 | Minimum necessary digits |
YY | “17” | Least significant 2 digits | |
YYY | “017”, “2017” | Padded to at least 3 digits | |
YYYY | “2017” | Padded to at least 4 digits | |
YYYYY | “02017” | Padded to at least 5 digits | |
Related Gregorian Year | r, rr, rr+ | 2017 | Minimum necessary digits |
Cyclic Year | U, UU, UUU | “甲子” | Abbreviated |
UUUU | “甲子” (for now) | Wide | |
UUUUU | “甲子” (for now) | Narrow | |
Extended Year | u+ | 4601 | Minimim necessary digits |
Quarter | Q | 2 | Single digit |
“02” | Two digits | ||
QQQ | “Q2” | Abbreviated | |
QQQQ | “2nd quarter” | Wide | |
QQQQQ | “2” | Narrow | |
Standalone Quarter | q | 2 | Single digit |
“02” | Two digits | ||
qqq | “Q2” | Abbreviated | |
qqqq | “2nd quarter” | Wide | |
qqqqq | “2” | Narrow | |
Month | M | 9 | Single digit |
MM | “09” | Two digits | |
MMM | “Sep” | Abbreviated | |
MMMM | “September” | Wide | |
MMMMM | “S” | Narrow | |
Standalone Month | L | 9 | Single digit |
LL | “09” | Two digits | |
LLL | “Sep” | Abbreviated | |
LLLL | “September” | Wide | |
LLLLL | “S” | Narrow | |
Week of Year | w | 2, 22 | Single digit |
ww | 02, 22 | Two digits, zero padded | |
Week of Month | W | 2 | Single digit |
Day of Year | D | 3, 33, 333 | Minimum necessary digits |
DD | 03, 33, 333 | Minimum of 2 digits, zero padded | |
DDD | 003, 033, 333 | Minimum of 3 digits, zero padded | |
Day of Month | d | 2, 22 | Minimum necessary digits |
dd | 02, 22 | Two digits, zero padded | |
Day of Week | E, EE, EEE | “Tue” | Abbreviated |
EEEE | “Tuesday” | Wide | |
EEEEE | “T” | Narrow | |
EEEEEE | “Tu” | Short | |
e | 2 | Single digit | |
ee | “02” | Two digits | |
eee | “Tue” | Abbreviated | |
eeee | “Tuesday” | Wide | |
eeeee | “T” | Narrow | |
eeeeee | “Tu” | Short | |
Standalone Day of Week | c, cc | 2 | Single digit |
ccc | “Tue” | Abbreviated | |
cccc | “Tuesday” | Wide | |
ccccc | “T” | Narrow | |
cccccc | “Tu” | Short | |
AM or PM | a, aa, aaa | “am.” | Abbreviated |
aaaa | “am.” | Wide | |
aaaaa | “am” | Narrow | |
Noon, Mid, AM, PM | b, bb, bbb | “mid.” | Abbreviated |
bbbb | “midnight” | Wide | |
bbbbb | “md” | Narrow | |
Flexible time period | B, BB, BBB | “at night” | Abbreviated |
BBBB | “at night” | Wide | |
BBBBB | “at night” | Narrow | |
Hour | h, K, H, k | See the table below | |
Minute | m | 3, 10 | Minimim digits of minutes |
mm | “03”, “12” | Two digits, zero padded | |
Second | s | 3, 48 | Minimim digits of seconds |
ss | “03”, “48” | Two digits, zero padded | |
Fractional Seconds | S | 3, 48 | Minimim digits of fractional seconds |
SS | “03”, “48” | Two digits, zero padded | |
Millseconds | A+ | 4000, 63241 | Minimim digits of milliseconds since midnight |
Generic non-location TZ | v | “Etc/UTC” | :time_zone key, unlocalised |
vvvv | “unk” | Generic timezone name. Currently returns only “unk” | |
Specific non-location TZ | z..zzz | “UTC” | :zone_abbr key, unlocalised |
zzzz | “GMT” | Delegates to zone_gmt/4 |
|
Timezone ID | V | “unk” | :zone_abbr key, unlocalised |
VV | “Etc/UTC | Delegates to zone_gmt/4 |
|
VVV | “Unknown City” | Exemplar city. Not supported. | |
VVVV | “GMT” | Delegates to `zone_gmt/4 | |
ISO8601 Format | Z..ZZZ | “+0100” | ISO8601 Basic Format with hours and minutes |
ZZZZ | “+01:00” | Delegates to `zone_gmt/4 | |
ZZZZZ | “+01:00:10” | ISO8601 Extended format with optional seconds | |
ISO8601 plus Z | X | “+01” | ISO8601 Basic Format with hours and optional minutes or “Z” |
XX | “+0100” | ISO8601 Basic Format with hours and minutes or “Z” | |
XXX | “+0100” | ISO8601 Basic Format with hours and minutes, optional seconds or “Z” | |
XXXX | “+010059” | ISO8601 Basic Format with hours and minutes, optional seconds or “Z” | |
XXXXX | “+01:00:10” | ISO8601 Extended Format with hours and minutes, optional seconds or “Z” | |
ISO8601 minus Z | x | “+0100” | ISO8601 Basic Format with hours and optional minutes |
xx | “-0800” | ISO8601 Basic Format with hours and minutes | |
xxx | “+01:00” | ISO8601 Extended Format with hours and minutes | |
xxxx | “+010059” | ISO8601 Basic Format with hours and minutes, optional seconds | |
xxxxx | “+01:00:10” | ISO8601 Extended Format with hours and minutes, optional seconds | |
GMT Format | O | “+0100” | Short localised GMT format |
OOOO | “+010059” | Long localised GMT format |
Formatting symbols for hour of day
The hour of day can be formatted differently depending whether a 12- or 24-hour day is being represented and depending on the way in which midnight and noon are represented. The following table illustrates the differences:
Symbol | Midn. | Morning | Noon | Afternoon | Midn. |
---|---|---|---|---|---|
h | 12 | 1…11 | 12 | 1…11 | 12 |
K | 0 | 1…11 | 0 | 1…11 | 0 |
H | 0 | 1…11 | 12 | 13…23 | 0 |
k | 24 | 1…11 | 12 | 13…23 | 24 |
Known restrictions and limitations
Although largely complete (with respect to the CLDR data), there are some known limitations as of release 0.1.0. These limitations will be removed before version 1.0.
Week of year The week of year is returned for the format symbol
w
. Currently it considers weeks of the year to be those defined for theISOWeek
calendar. This means that January 1st may not be the start of the first week of the year and December 31st may not be the last day of the last week of the year.Week of month The week of the mornth is returned for format symbol
W
. Currently it considers weeks of the month to start on the first day of the month which is inconsistent with the ISOWeek standard and different from theweek_of_year
calculation.Timezones Although the timezone format codes are supported (formatting symbols
v
,V
,x
,X
,z
,Z
,O
) not all localisations are performed. Only that data available within aDateTime
struct is used to format timezone data.First day of week is always Monday All formatting is done with Monday as the first day of the week. In several territories this is not a reasonable assumption. CLDR provides data to support a different starting day for the week. This will be implemented before version 1.0
Only calendar is Gregorian (Calendar.ISO) CLDR defines many calendar systems (see
Cldr.Calendar.known_calendars/0
) however only Calendar.ISO (proleptic Gregorian calendar) is supported in this release.Variants Some formats defines variants in the CLDR data. For example, formatting an Era in the gregorian calendar is, by default, returned as
AD
orBC
. CLDR also defines the variantsCE
andBCE
. Currently the API does not provide a way to specify these variants.
Installation
Note that :ex_cldr_dates_times
requires Elixir 1.5 or later.
Add ex_cldr_dates_time
as a dependency to your mix
project:
defp deps do
[
{:ex_cldr_dates_times, "~> 0.1.1"}
]
end
then retrieve ex_cldr_dates_times
from hex:
mix deps.get
mix deps.compile