topic Re: Restricting to first visit in App Development

Restricting to first visit

aswinnar — Sat, 16 Nov 2024 17:44:49 GMT

I have a requirement where I need to show a graph of the number of new visits per month for a study

So for a Study A, for visits we have to use the visit types which are shown as:

V0 for example would be the new visits that I am needing to use for my chart. Other studies have different visit types for new visits like T0, or V1. What expression can I use to show the count of the first visit type?

For example, for study A if I take count of v0 for Jan I should get 24, but with the expression that I am using:

=Count({$<visittype={$(=min(visittype))}>}visittype)

I am getting 0, not 24. Is there something wrong with the expression that I am using?

Re: Restricting to first visit

MayilVahanan — Fri, 04 Dec 2020 08:34:54 GMT

HI @aswinnar

V0, V1 is the string. so you can try with Minstring() function

=Count({$<visittype={'$(=Minstring(visittype))'}>}visittype)

Create a flag or dual function to calculate it.

Re: Restricting to first visit

aswinnar — Sat, 05 Dec 2020 05:03:50 GMT

Hi @MayilVahanan ,

That seems to be working, however when applying to my line chart instead of showing multiple lines for each study I am only getting one line now. Is there a reason for this? If I filter for each one they show, and if I use an expression such as

=Count({$<visittype+={'$(=Minstring(visittype))'}>}visittype)

All the lines for the studies show, but not the case for the expression you gave. Any reason why?

Re: Restricting to first visit

MayilVahanan — Sat, 05 Dec 2020 05:47:08 GMT

Hi @aswinnar

Can you provide the sample data and expected output. so that, its help to understand better.

Re: Restricting to first visit

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Re: Restricting to first visit

aswinnar — Sat, 05 Dec 2020 12:04:49 GMT

Hi @MayilVahanan

PFA excel file containing sample data that I am using for the graph

I am trying to create a multi line chart based on new visits per month for a study. The line graph should show multiple lines, for each study. The issue I had come across was implementing the logic to get the min visits (new visits), using the expression Count({$<visittype+={'$(=Minstring(visittype))'}>}visittype)

Using that expression, I am only getting a single line, the other lines for the other studies are not showing up.

In the line chart I am also using an aggregated dimension for visit date, as we are showing new visits over 2020 for different studies

The calculated dimension is: =aggr(only({<Visit_Date ={"*2020"}>} Visit_Date),Visit_Date)

Let me know if you are needing any more details

Re: Restricting to first visit

MayilVahanan — Sun, 06 Dec 2020 03:45:56 GMT

Hi @aswinnar

You need to add study as Dimension to display multiple lines for study in line chart

like below

Re: Restricting to first visit

aswinnar — Sun, 06 Dec 2020 06:13:16 GMT

Hi @MayilVahanan

As shown in the screenshots I have added Study as a dimension in the qlik linechart, but I am still only getting the one line

Is there something else that I am doing wrong? Or is it a Qlik Sense bug? I have also tried with the vizlib linechart extension and am encountering the same issue

Re: Restricting to first visit

aswinnar — Mon, 07 Dec 2020 01:59:51 GMT

Hi @MayilVahanan ,

I had told you the wrong expression,

I am using

Count({$<visittype={'$(=Minstring(visittype))'}>}visittype) as the measure, which is causing me problems.

Whenever I use Count({$<visittype+={'$(=Minstring(visittype))'}>}visittype) it is working but I am needing to create chart for Count({$<visittype={'$(=Minstring(visittype))'}>}visittype), so that is should show for only the new visits, not for all the visits.

Re: Restricting to first visit

MayilVahanan — Mon, 07 Dec 2020 07:47:21 GMT

Hi @aswinnar

For sample data, can you say the expected output?

meanwhile, you can try like below also

Sum(Aggr(if(visittype = MinString(Total<STUDY> visittype), 1), STUDY, Visit_Date, visittype))

Re: Restricting to first visit

aswinnar — Mon, 07 Dec 2020 08:18:27 GMT

Hi @MayilVahanan ,

I have attached an excel sheet of the expected values for the visitytpe for 2020 only, as that is what we are needing for the requirement.

I believe the issue might be with the expression itself as I have tried with other expressions and I am getting all the studies in the line chart. It seems only with this expression it is causing error with the chart, though the expression is yielding the correct results.

I have also tried your expression and I am getting straight lines for all studies.

Appreciate all the help so far, thank you 🙂