error presentation

[lorenzo9898]

when I changed the output option from html to pdf it generates an error both when I try to change the output option and when knit to pdf
how can i solve?

[mattwarkentin]

I think your problem is the first line of your YAML header. You can only specific output formats after the output: key.

Try changing your YAML header to something like:

---
author: "Lg"
date: "Anno Accademico 2018-2019"
output:
  slidy_presentation: default
  ioslides_presentation: default
  beamer_presentation: default
fonttheme: structurebold
theme: Antibes
title: "Utilizzo di internet"
---

Note that when clicking the Knit button, you will only get the rendered output for the first output in listed in YAML (in this case slidy_presentation). If you want to render all three, you must call the rendering function directly with:

rmarkdown::render('name_of_file.Rmd', output_format = "all")