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getItems()
array getItems(string question ID, string comparison, [int answer code])
With the help of the function getItems(), you can determine which items in a question are available, or which items have been checked off.
The function returns an array of question IDs, e.g. (1,2,4,5,6,9,10). These IDs can be added directly to another question by using the command question(). By doing so, only the items that a person previously selected as being relevant can be displayed in a second question (e.g. only evaluate magazines that the participant reads), see Use Selected Items in Another Question.
- Question ID
The question's ID e.g. “AB01” - Comparison
Sets out the criteria of the items listed. It is important that the mode is put in quotation marks. The potential modes of comparison can be seen in the following table.
| Comparison | Description |
|---|---|
'all' | all items in the question, useful e.g. for randomization. In this instance, an answer code is not specified. |
'>' | lists all items with a greater answer code than the specified answer code. Therefore, a '>', in conjunction with an answer code of 3 in a scale of 1-5, would only select items for which a value over the middle of the scale was checked off. |
'>=' or 'min' | lists all items with at least the minimum answer code. |
'<=' or 'max' | items with the maximum answer code. Items with missing values(e.g. “no answer”), which technically have an answer code of -1, are not (!) listed here though. |
'<' | items with a valid answer that is less than the answer code specified. |
'==', '=', 'is' or 'equal' | items with the exact answer code specified. |
'!=', '<>' | Items that have not received this answer code. |
'answered' | items answered. Note: The option is not applicable for multiple choice selections, as a respondent cannot not answer the options. |
'missing' | items not answered or missing. |
'valid' | items with a valid answer, and therefore have not been left empty or given an answer of “do not know”. Note: In a multiple choice selection, 'no answer' selected is also a valid answer. Here, use ' == ' in conjunction with answer code 2 to determine the options selected. |
'invalid' | items left empty or given an answer of “do not know”. |
Note: As is the case with value(), this function can only determine the answers of a participant on the page after the question. If the function is on the same page as the question, it does not work correctly because the answers will not yet have been transmitted to the server when the “next” button is pressed.
Use Selected Items in Another Question
In the following example, question AB01 (a matrix question – scale) is asked on page 1, in which the participant has to specify how often they read different magazines.
On the following page 2, only items used at least “rarely” (answer code 2) should be displayed.
This example assumes that AB02 has just as many items as AB01. In addition, matching items must also have the same ID. Thus, item 1 could be “mirror” in both questions, and item 2 could be “star”.
Tip: The most simple way to achieve this is by creating a question, duplicating it, and only changing the type of question and question text in the copy.
// page 2 // determine items used at least "rarely" (2) $itemlist = getItems('AB01', 'min', 2); // only show these items in AB02 question('AB02', $itemlist);
The question AB04 should now be asked on page 3 – but only for the items, which according to AB01, are used no less frequently than “often” (answer code 3).
Question AB04 must also have the same items with the same IDs as question AB01.
// page 3 $itemlistB = getItems('AB01', 'min', 3); // only show these items in question AB04 question('AB04', $itemlistB);
Tip: Please also read the chapter Use Selected Items in Another Question
Further Examples
// list of items, for which specifically "never" was selected $itemlist = getItems('AB01', '==', 1); // list of items, for which a maximum of 'rarely' was selected $itemlist = getItems('AB01', '<=', 2); // list of all items with a valid answer $itemlist = getItems('AB01', 'valid'); // list all items of the question $itemlist= getItems('AB01', 'all'); html('<p>The question shows '.count($itemlist).' Items.</p>'); // list of all items answered with never (1) or daily (4) $list1 = getItems('AB01', '==', 1); $list2 = getItems('AB01', '==', 4); $itemlist = array_merge($list1, $list2);
In the following example, the combination of getItems() with the PHP function count() is shown. The function count() reveals the length of an array. As a result, for example, it can be checked whether the minimum of a certain number of items fulfil the criterion from getItems().
// determine unanswered items in question AB01 $missing = getItems('AB01', 'missing'); // if at least one of them is missing, then the question should be shown again if (count($missing) > 0) { question('AB01'); }
Tip: Please read the guide to the function repeatPage() for more information regarding the previous example.
