how can I summarize survey answers from a data table in R shiny?

[martin.R]

You should be aware that data.table and DT::datatable are very different things, so it's possible you have confused these. As you are already using the tidyverse function read_csv I suspect this is the case.

The error message is likely because you have not loaded data.table via: library(data.table)

The tidyverse/dplyr equivalent would be something like dt %>% summarise(x = sum(a))

For any further help re the plots you should produce a reproducible example:

FAQ: What's a reproducible example (`reprex`) and how do I create one?

Why reprex? Getting unstuck is hard. Your first step here is usually to create a reprex, or reproducible example. The goal of a reprex is to package your code, and information about your problem so that others can run it and feel your pain. Then, hopefully, folks can more easily provide a solution. What's in a Reproducible Example? Parts of a reproducible example: background information - Describe what you are trying to do. What have you already done? complete set up - include any library() calls and data to reproduce your issue. data for a reprex: Here's a discussion on setting up data for a reprex make it run - include the minimal code required to reproduce your error on the data…

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