Hi,

My question is a little specific.
In one of my survey, i ask participants to input a number of 6 characters wich is a multiple of 13. (The number is like 450013 or 790039, the two first characters are fixed, this number is gave to the participants on a paper).
I would like to make a validation to this question, if the number begin well by 45 or 79 and if the number is well a multiple of 13.
I didn't know how to do the expression in the validation field.

I use limesurvey 3.17.8 and vanilla theme.

Can you help me ?

Thanks.

bf

Hi,
you probably studied the demo surveys in the demo installation.
demo.limesurvey.org/admin/admin.php
In "Demo of em_validation_sq" you find a question called "Enter multiple of 5".

So take this validation - adapted to 13 - and add a validation to check if the value starts with 45 or 79, function "substr".
And remember, the first index of "substr" is "0".

Joffm

Sincererly, thank you !
I'm ashamed of saying that i didn't know the demo installation. That's great.
I found in the manual that modulo-function is not supported and i have to use the floor function to do this, but i didn't know how. Finally, it wasn't so difficult.
Thank you too for the substr function, it works well.

My equation : (substr(this, 2,4) / 13) == floor(substr(this, 2,4)/13) && substr(this, 2,4) > 0 && (substr(this, 0,1) == 45 OR 79)
I added a function ">0" because if the participant enters 790000, it works, what i don't want to.

One thing i don't understand, what is the difference between "Subquestion validation equation" and "Question validation equation" ? My question type is short free text, so i think i have to use "Question validation equation", but i'm not sure.
Also, what is the "Validation" field in "general options" category of the question ? Is that different from the "Question validation equation" from the Logic category ?

Thanks for your help.

bf

In sub question : you can use this as a shortcut to current element.

For example `this > 3` in multi number : then each number must be up than 3.

There are a devlopement project to set the error input on the broken element only : github.com/LimeSurvey/LimeSurvey/blob/d2...ger_helper.php#L6787

But i think this sentence is here since 1.92 version … a long time TODO …

Thank you for you explanation Denis.
Indeed, a long time !

So if i understand well, for a single numerical input, i can input the equation with "this" in "Question validation equation" as in "Subquestion validation equation", it doesn't make a difference, no ?

bf


Edit : i add "strlen(this) == 6" to my equation to force correct string length
so : strlen(this) == 5 && (substr(this, 2,4) / 13) == floor(substr(this, 2,4)/13) && substr(this, 2,4) > 0 && (substr(this, 0,1) == 45 OR 79)

bferrie wrote: So if i understand well, for a single numerical input, i can input the equation with "this" in "Question validation equation" as in "Subquestion validation equation", it doesn't make a difference, no ?

If i don't make error this is related to subquestion only in Subquestion validation equation

Ok, thanks.
That's a bit complicated for me....

When i take the survey "Demo of em_validation_sq" that Joffm advised me, if i look the logic file, there is no difference (for me) between questions with Subquestion validation equation and others with Questions validation equation. The transcription of the equation "this/5 == floor(this/5)" seems to be the same.

I think i don't have the skills needed to fully understand that, but my problem is solved, the equation works in "Question validation equation", so thanks to you two.

bf