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The {(...)} "expression markup" allows for a variety of string and formatting operations to be performed from within markup. Operations defined by this recipe include substr, ftime, strlen, rand, toupper / tolower, ucfirst, ucwords, pagename and asspaced.

substr

The "substr" expression extracts portions of a string. The arguments are

the string to be processed. Always quote the string to be processed.
the initial position of the substring. Note that the initial position argument is zero-based (i.e., the first character is referenced via a "0").
the number of characters to extract

 {(substr "PmWiki" 2 3)}
 {(substr "PmWiki" 2)}
 {(substr "PmWiki" 0 1)}
 {(substr "PmWiki" 0 -3)}
 {(substr "PmWiki" -3)}

 Wik
 Wiki
 P
 PmW
 iki

To obtain the last n characters of a string use {(substr "string" -n)}
To truncate the last n characters of a string use (substr "string" 0 -n)}

ftime

"Ftime" expressions are used for date and time formatting. The generic form is

{(ftime "fmt" "when")}

{(ftime fmt="fmt" when="when")}

where fmt is a formatting string and when is the time to be formatted. The arguments can be in either order and may use the optional "fmt=" and "when=" labels.

Examples:

 {(ftime)}
 {(ftime fmt="%F %H:%M")}
 {(ftime %Y)}
 {(ftime fmt=%T)}
 {(ftime when=tomorrow)}
 {(ftime fmt="%Y-%m-%d" yesterday)}
 {(ftime "+1 week" %F)}
 {(ftime fmt=%D "+1 month")}
 {(ftime fmt="%a%e %b" when="next
week")}

 2026-10-23 18:30  [UTC-7]
 2026-10-23 18:30
 2026
 18:30:57
 2026-10-24 00:00  [UTC-7]
 2026-10-22
 2026-10-30
 11/23/26
 Mon26 Oct

The fmt parameter is whatever is given by "fmt=", the first parameter containing a '%', or else the site's default. The formatting codes are described at http://php.net/strftime. In addition to those, '%F' produces ISO-8601 dates, and '%s' produces Unix timestamps. Some common formatting strings:

     %F                # ISO-8601 dates      \"2026-10-23"
     %s                # Unix timestamp      "1792794657"
     %H:%M:%S          # time as hh:mm:ss    "18:30:57"
     %m/%d/%Y          # date as mm/dd/yyyy  "10/23/2026"
     "%A, %B %d, %Y"   # in words            "Friday, October 23, 2026"

The when parameter understands many different date formats. The when parameter is whatever is given by "when=", or whatever parameter remains after determining the format parameter. Some examples:

    2007-04-11            # ISO-8601 dates
    20070411              # dates without hyphens, slashes, or dots
    2007-03               # months
    @1176304315           # Unix timestamps (seconds since 1-Jan-1970 00:00 UTC)
    now                   # the current time
    today                 # today @ 00:00:00
    yesterday             # yesterday @ 00:00:00
    "next Monday"         # relative dates
    "last Thursday"       # relative dates
    "-3 days"             # three days ago
    "+2 weeks"            # two weeks from now

Note: If you want to convert a Unix timestamp you must prefix with the @. Thus, "{(ftime "%A, %B %d, %Y" @1231116927)}".

The when parameter uses PHP's strtotime function to convert date strings according to the GNU date input formats; as of this writing it only understands English phrases in date specifications.

The variable $FTimeFmt can be used to override the default date format used by the "ftime" function. The default $FTimeFmt is $TimeFmt.

strlen

The "strlen" expression returns the length of a string. The first argument is the string to be measured.

 {(strlen "{$:Summary}")}

rand

The "rand" expression returns a random integer. The first argument is the minimum number to be returned and the second argument is the maximum number to be returned. If called without the optional min, max arguments rand() returns a pseudo-random integer between 0 and RAND_MAX. If you want a random number between 5 and 15 (inclusive), for example, use (rand 5 15).

 {(rand)}
 {(rand 1 99)}

 950014276
 20

toupper / tolower

The "toupper" and "tolower" expressions convert a string into uppercase or lowercase. The first argument is the string to be processed.

 {(toupper "{$:Summary}")}
 {(tolower "{$:Summary}")}

 STRING AND FORMATTING OPERATIONS
 string and formatting operations

ucfirst / ucwords

The "ucfirst" expression converts to uppercase the first character of the string, and "ucwords", the first character of each word. The first argument is the string to be processed.

 {(ucfirst "{$:Summary}")}
 {(ucwords "{$:Summary}")}

 String and formatting operations
 String And Formatting Operations

pagename

The "pagename" expression builds a pagename from a string. The first argument is the string to be processed.

 {(pagename "{$:Summary}")}

 PmWiki.StringAndFormattingOperations

asspaced

The "asspaced" expression formats wikiwords. The first argument is the string to be processed.

 {(asspaced "{$FullName}")}

 Pm Wiki.Markup Expressions

Nesting expressions

Markup expressions can be nested:

 {(tolower (substr "Hello World" 2))}

 llo world

Notes

For PmWikis version 2.2.33 or older, the string-processing expressions may not work properly on multibyte UTF-8 characters. Newer versions should work fine.