phpstringfunctionrange

Native PHP functions that allow double-dot range syntax


Some native PHP string functions have a parameter which is a string of one or more unordered characters (also referred to as a "character mask"). In some cases, character ranges can be expressed using double-dot syntax.

For example: echo trim('foo24', '0..9'); prints foo because 2 and 4 fall within the 0 through 9 range.

What are the other native PHP string functions with the same feature?


Solution

  • Native PHP string functions that respect double-dot range expressions:

    • addcslashes() (Demo)

       echo addcslashes('adobe', 'a..e');
       // \a\do\b\e
      
    • chop() -- alias of rtrim() (Demo)

       echo chop('adobe', 'a..e');
       // ado
      
    • ltrim() (Demo)

       echo ltrim('adobe', 'a..e');
       // obe
      
    • rtrim() (Demo)

       echo rtrim('adobe', 'a..e');
       // ado
      
    • str_word_count() (Demo)

       var_export(
           str_word_count('do not break|on|pipe', 1, '{..}')
       );
       // ['do', 'not', 'break|on|pipe']
      
    • trim() (Demo)

       echo trim('adobe', 'a..e');
       // o
      
    • ucwords() (Demo)

       echo ucwords('backdoorman', 'a..e');
       // BaCkdOormaN
      

    Here are some native functions where ranged expressions are not expanded, but might be reasonable candidates for the feature:

    • strcspn() (Demo) (expansion would be reasonable)

       echo strcspn('cdplayer', 'b..e');
       // 6
       // 0 if range enabled
      
    • strpbrk() (Demo) (expansion would be reasonable)

       echo strpbrk('stackoverflow', 'b..f');
       // flow
       // ckoverflow if range enabled
      
    • strspn() (Demo) (expansion would be reasonable)

       echo strspn('adobe', 'a..e');
       // 1
       // 2 if range enabled
      
    • strtok() (Demo) (expansion would be reasonable)

       echo strtok('toddler', 'a..e');
       // toddl
       // to if range enabled
      
    • strtr() (Demo) (out of topic scope because not technically a character mask -- character order matters)

       echo strtr('adobe', 'a..e', 'A..E');
       // AdobE
       // ADoBE if range enabled
      

    Due to technical challenges of supporting .. syntax with multibyte characters, the following native functions will not allow ..
    Ref: https://wiki.php.net/rfc/mb_trim

    • mb_ltrim()
    • mb_rtrim()
    • mb_trim()