Native PHP functions that allow double-dot range syntax

Question

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?

Answer 1

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()