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How to use the Filter(s) Dropdown to Quickly Filter R Outputs using QFilter

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If your R Output uses variables or a raw data table as an input (as opposed to a table/visualization/other output), you can use the standard Filter: dropdowns to quickly filter your R Output. These are referenced using QFilter in R code and will automatically update based on the filters applied to R Output without the need to edit the R code. This is useful when showing raw data as your final output or if you'd like to filter raw data used in a custom calculation.

For example, you can go from this showing all responses in the data set:

mceclip2.png

To this showing only those records filtered in using the Filter: dropdowns:

mceclip1.png

Or this showing a custom output only including the filtered responses, such as a table of counts of each response: 

mceclip4.png

 

Requirements

  • An R Output that uses variables from the data set or an unfiltered raw data table. 
  • One or more filter variables from the same data set.

Method

In this example, we will return a list of the ages for Females in our data set using the Filter: dropdown. Note there are 600 records in total in the dataset. 

1. Paste the following in the R CODE box of your R Output, note our variable is named Age:

Age[QFilter]

2. Using the Filter: dropdowns, apply the desired filter variable(s). If you apply multiple filters, they are joined using AND logic, and all filters must be met to be filtered into the code. Here, we will apply a Female filter:

mceclip0.png

Our R output now returns 301 records, the same number as females in our data set.

3. Your final results doesn't need to be raw data, you can do further calculations with the filtered data to output a custom final result. Change the R CODE to the following to show a table of counts for each age sorted in decreasing order for Females (or whatever filters are applied):

sort(summary(Age[QFilter]),decreasing=T)

mceclip5.png

 

Notes

  • If a filter(s) is selected in the Filter: dropdown, QFilter will be a series of TRUE and FALSE values as many cases as is in your data set. You can then use this to filter the raw data/variables being used in your calculation using this variable.
  • If multiple filters are selected, QFilter will return with a final series of TRUE and FALSE values evaluated by combining the filters using the AND operator, i.e. if both male and under 18 filters are applied, the final values will reflect cases that are male AND under 18.
  • The series of TRUE and FALSE values automatically updates when the filters change in the dropdown.
  • If no filters are applied, it is a single value of TRUE.
  • If you apply filters to your Calculation via Inputs > FILTERS & WEIGHT > Filter(s) but do not include QFilter in your code, you will receive the following warning: troubleshoot_filter5.png
  • The Variable Label is available as an attribute (i.e., attr(QFilter, "label")). Where there are multiple filters, they are concatenated as a list (e.g., "Male, 18 to 24 and Tall").
  • The Variable Name is available as an attribute (i.e., attr(QFilter, "name")). Where there are multiple names, they are concatenated as with labels.

 

See Also

How to Learn R

How to Work with Conditional R Formulas

How to Filter Raw Data Using R

How to Create Filters in Q

 

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