86 lines
4.5 KiB
Plaintext
86 lines
4.5 KiB
Plaintext
created: 20140418142957325
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modified: 20230226144359284
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tags: Features
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title: DateFormat
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type: text/vnd.tiddlywiki
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The default representation of dates is a compact string such as <<.value 20211002153802059>>. The associated template is `[UTC]YYYY0MM0DD0hh0mm0ss0XXX`. For example, the <<.field created>> and <<.field modified>> fields are stored like this.
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The display format for this string can be controlled with a template. For example, transcluding the <<.field modified>> field automatically applies a template to display the date as <<.value "Sat Oct 02 2021 17:40:50 GMT+0200 (Central European Summer Time)">>. A few widgets and filter operators allow you to manually specify a template, for example the ViewWidget:
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`<$view field=modified format=date template="DDth mmm YYYY 0hh:0mm:0ss" />`
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The date string is processed with the following substitutions:
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|!Token |!Substituted Value |
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|`ddddd` |<<.from-version "5.2.0">> Day of year (1 to 365, or 366 for leap years) |
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|`0ddddd` |<<.from-version "5.2.0">> Zero padded day of year (001 to 365, or 366 for leap years) |
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|`DDD` |Day of week in full (eg, "Monday") |
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|`ddd` |Short day of week (eg, "Mon") |
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|`dddd` |<<.from-version "5.2.0">> Weekday number from 1 through 7, beginning with Monday and ending with Sunday |
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|`DD` |Day of month |
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|`0DD` |Adds a leading zero |
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|`DDth` |Adds a suffix |
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|`WW` |ISO-8601 week number of year |
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|`0WW` |Adds a leading zero |
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|`MMM` |Month in full (eg, "July") |
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|`mmm` |Short month (eg, "Jul") |
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|`MM` |Month number |
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|`0MM` |Adds leading zero |
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|`YYYY` |Full year |
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|`YY` |Two digit year |
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|`wYYYY` |Full year with respect to week number |
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|`aYYYY` |<<.from-version "5.1.23">> Full year but negative dates are displayed as positive |
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|`wYY` |Two digit year with respect to week number |
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|`{era:BCE||CE}` |<<.from-version "5.1.23">> Displays a different string for years that are negative, zero or positive (see below) |
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|`hh` |Hours |
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|`0hh` |Adds a leading zero |
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|`hh12` |Hours in 12 hour clock |
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|`0hh12` |Hours in 12 hour clock with leading zero |
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|`mm` |Minutes |
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|`0mm` |Minutes with leading zero |
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|`ss` |Seconds |
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|`0ss` |Seconds with leading zero |
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|`XXX` |Milliseconds |
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|`0XXX` |Milliseconds with leading zero |
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|`am` or `pm` |Lower case AM/PM indicator |
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|`AM` or `PM` |Upper case AM/PM indicator |
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|`TZD` |Timezone offset |
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|`TIMESTAMP` |<<.from-version "5.2.4">> Number of milliseconds since the [[ECMAScript epoch|https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#the_ecmascript_epoch_and_timestamps]], 1 January 1970. |
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|`\x` |Used to escape a character that would otherwise have special meaning |
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|`[UTC]`|Time-shift the represented date to UTC. Must be at very start of format string|
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Note that other text is passed through unchanged, allowing commas, colons or other separators to be used.
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The `{era:BCE||CE}` notation can specify different strings for years that are negative, zero or positive. For example `{era:BC|Z|AD}` would display <<.value BC>> for negative years, <<.value AD>> for positive years, and <<.value Z>> for year zero.
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! Examples
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|!Template |!Output |
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|`DDth MMM YYYY` |16th February 2011 |
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|`DDth MMM \M\M\M YYYY` |16th February MMM 2011 |
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|`DDth mmm YYYY 0hh:0mm:0ss` |16th Feb 2011 11:38:42 |
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!! Using <<.value TIMESTAMP>> to calculate time difference
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You can calculate the difference between two dates by doing the following:
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# Convert both dates to timestamps
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# Subtract the later date from the earlier one -- if you don't know which one is earlier use the <<.olink "abs">> operator to get an absolute value after subtraction
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# Divide the resulting number by the number of milliseconds in your chosen interval
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Here is an example of calculating the number of days that passed between creation and last modification of current tiddler:
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* Convert the <<.field created>> and <<.field modified>> fields to timestamps
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* Divide their difference by <<.value 86400000>> which is the number of milliseconds in a day
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** 1000 milliseconds per second × 60 seconds per minute × 60 minutes per hour × 24 hours per day = 86,400,000 milliseconds per day
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<$macrocall $name=".example" n="0" eg="""<$let
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timestamp-modified={{{ [{!!modified}format:date[TIMESTAMP]] }}}
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timestamp-created={{{ [{!!created}format:date[TIMESTAMP]] }}}
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difference-days={{{ [<timestamp-modified>subtract<timestamp-created>divide[86400000]floor[]] }}}>
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* ''Modified date:'' <$text text={{{ [{!!modified}format:date[YYYY-0MM-0DD]] }}}/>
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* ''Created date:'' <$text text={{{ [{!!created}format:date[YYYY-0MM-0DD]] }}}/>
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* ''Difference in days:'' <<difference-days>> days
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</$let>"""/> |