Cumulative sum of repeat group calculation

Hello,

I am using a series of questions to calculate the amount of water that a household uses each day, per water container. I am using a simple calculation to multiply the input for “container capacity” and “number of times container was filled.” I am doing this in a repeat group so that multiple water containers can be counted. I am now trying to calculate a cumulative sum of the calculations (total water used, across all containers).

In CommCare, I am able to accomplish this with a simple “sum” function, but I cannot seem to get the same effect in KoBo. How can I do this in KoBo?

Thank you in advance,
Lauren

Hi Lauren

Done several calculate functions with KOBO forms my advice would be you purse the number of times this can happen in a question construct and then apply the multiplication function for the same… as it repeat questions have an indefinite nature which makes it hard to compound a calculation…

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On Tue, 16 Dec 2014 23:58 Lauren lauren....@gmail.com wrote:

Hello,

I am using a series of questions to calculate the amount of water that a household uses each day, per water container. I am using a simple calculation to multiply the input for “container capacity” and “number of times container was filled.” I am doing this in a repeat group so that multiple water containers can be counted. I am now trying to calculate a cumulative sum of the calculations (total water used, across all containers).

In CommCare, I am able to accomplish this with a simple “sum” function, but I cannot seem to get the same effect in KoBo. How can I do this in KoBo?

Thank you in advance,
Lauren

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Hi,

There is a way to do the same, but with a caveat that no element can be empty, otherwise sum() will (correctly) return NaN (in that respect KoBo’s Enketo is a bit stricter than Commcare). You can achieve this by using a calculated item such as this: “if(${container_capacity} > 0 and ${number_containers_filled} > 0, ${container_capacity} * ${number_containers_filled}, 0)” inside the repeat, and sum() the values of this calculated item.

See similar example here: sum - Google Sheets

Cheers,
Martijn

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On Monday, December 22, 2014 1:10:37 PM UTC-7, Kenyan Aloo wrote:

Hi Lauren

Done several calculate functions with KOBO forms my advice would be you purse the number of times this can happen in a question construct and then apply the multiplication function for the same… as it repeat questions have an indefinite nature which makes it hard to compound a calculation…

On Tue, 16 Dec 2014 23:58 Lauren laure...@gmail.com wrote:

Hello,

I am using a series of questions to calculate the amount of water that a household uses each day, per water container. I am using a simple calculation to multiply the input for “container capacity” and “number of times container was filled.” I am doing this in a repeat group so that multiple water containers can be counted. I am now trying to calculate a cumulative sum of the calculations (total water used, across all containers).

In CommCare, I am able to accomplish this with a simple “sum” function, but I cannot seem to get the same effect in KoBo. How can I do this in KoBo?

Thank you in advance,
Lauren

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