Simple: New to R, seek some advice

[RaulS]

Hello, dear all!

I won't take too much of your time with this introduction.
From the attached table:
How many values ''munte=mountain'' are in the table under the column ''altitudine=altutude''?
What is the medium density of Daphnia based on the ''campie=plain (Daphnia collected from plain rivers) '' criterium?
What is the maximum value of the pH from the column ''nutrienti=Nutrients'' specifically ''mezotrof= Mesotrophic lakes''?

Thank you in advance,
Raul

[StatSteph]

This looks like a homework assignment. Please take a look at the homework policy (FAQ: Homework Policy) and the reproducible examples (FAQ: How to do a minimal reproducible example ( reprex ) for beginners) so that people can help you out better.

[RaulS]

Not really homework.
More like a food for thought exercise to get familiar with RStudio.

[technocrat]

See the FAQ: How to do a minimal reproducible example reprex for beginners for when looking for more specific answers.

Using the built-in mtcars data

sum(mtcars$carb == 3)
#> [1] 3
median(mtcars[which(mtcars$carb == 3),"mpg"])
#> [1] 16.4

The second example is an exemplary pattern for the second and third questions.

[RaulS]

Thank you! The purpose of this was to put me on the right path and not to solve it for me. That would have been totally useless. I wouldn't have learned anything.
That's why I have not classified it as homework. Homework is about a result.
I am here for the way there; building logical mechanisms to learn this program.
All the best everyone!