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Random Media Loading

darty
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9 years 3 months ago #155547 by darty

Random Media Loading was created by darty

Hi!

I have a dataset of media files (> 2000 files), each with their own ID and metadata. I'd like to conduct a study where every user answers questions about 10 random media files.

My current idea is to have each question retrieve a random ID from an external server and link that ID to the current question group. So every question retrieves a URL from a fixed address, then parses the ID and the media URL from the response, completes the ID into a hidden field and includes the media file in the webpage.

I'm not sure if this is the correct way to proceed with this, and I was wondering if someone could point me in the right direction to achieve this.

Thank you!

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holch
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9 years 3 months ago #155553 by holch

Replied by holch on topic Random Media Loading

You could create a random number via Expression Manager (there are many examples here in the forum on how to do that).
You would have to create as many equation questions and save random numbers into them as you will want to show files per user (in your case 10).
Only problem: There is a slight chance that you could get a file more than once per user.

Help us to help you!

Provide your LS version and where it is installed (own server, uni/employer, SaaS hosting, etc.).
Always provide a LSS file (not LSQ or LSG).

Note: I answer at this forum in my spare time, I'm not a LimeSurvey GmbH employee.

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tpartner
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9 years 3 months ago #155566 by tpartner

Replied by tpartner on topic Random Media Loading

You can use JavaScript to load the inputs of a multiple-numeric question and then use those values in your paths to the videos.

This will load a question with 10 random numbers between 1 and 2000:

Code:

<script type="text/javascript" charset="utf-8">
	$(document).ready(function() {
 
		// Identify this question
		var qID = {QID};
		var thisQuestion = $('#question'+qID);
		
		// Build an array of 10 random numbers between 1 and 2000
		var numbers = [];
		while(numbers.length < 10){
			var randomnumber = Math.ceil(Math.random()*2000)
			if(numbers.indexOf(randomnumber) > -1) continue;
			numbers[numbers.length] = randomnumber;
		}
		
		// Load the question
		$(numbers).each(function(i, value) {
			$('input[type="text"]:eq('+i+')', thisQuestion).val(value);
		});
	});
</script>

Sample survey attached: