====== id() ======

''string **id**(string //category//, integer //question//)''

''string **id**(string //category//, integer //question//, integer //Item//)''

''string **id**(string //question identifier//, integer //Item//)''
    
The function ''id()'' is generating a formally correct question- or item identifier out of single statements about the category, question and (optional) item. This question- or item identifier can be used e.g. in ''[[value]]'' or ''[[put]]''. The function can be helpful, when the item identifier is specified as a number, like e.g. ''1'' instead of ''01''.



  * //Category// -- Double-digit identifier of a category, e.g. '''AB'''
  * //Question// -- Numeric identifier of a question within a category, e.g.''1'', '''01'''
  * //Question identifier// -- Entire identifier of a question (incl. category), e.g. '''AB01'''
  * //Item// -- Numeric identifier of an item or an option within a question, e.g. ''2'', '''02'''


===== Return value =====

The function delivers the entire identifier of a question (e.g. '''AB01''') or an item, when the parameter //Item// was set (e.g. '''AB01_01''').


===== Example =====

The following example lists options within a scale SK01, which were rated with a min. value of 3 from the participant (e.g. on a scale of 1 to 5). The evaluation should be shown in brackets. The evaluation is generated by ''[[value]]''. The therefore necessary variable-identifier (which matches the item-identifier) is generated with ''id()''.



<code php>
// find items with evaluation 3+
$items = getItems('SK01', 'min', 3);
// go through all items
foreach ($items as $item) {
  // identify text
  $text = getItemtext('SK01', $item);
  // identify value
  $wert = value(id('SK01', $item));
  // show in questionnaire
  html('<p>'.$text.' ('.$wert.')</p>);
}
</code>
