Hi, and welcome!
Two preliminaries:
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Please see the FAQ: What's a reproducible example (`reprex`) and how do I do one? Using a reprex, complete with representative data will attract quicker and more answers.
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Check the homework policy.
This is a process that everyone either has or will go through to learn R. It helps to keep in mind that
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Everything in
Ris anobject, meaning it has content and properties that can be acted upon. -
Some objects can change other objects, these are
functions. -
Functions are just what they sound like, school algebra: f(x) = y where f, the function object operates on one or more x
argumentobjects and returns avalueobject as a result.
R has an endless richness of functions, but sometimes finding the right one can be a challenge. If not mentioned in your lecture notes or the text, try typing into the R command line
help(read.table)
which will lead you to the function for the first step. (Hint: csv stands for comma separated value; also, whenever you use a function, you probably also need to assign the return value to something.)
To see the last row of the built in object mtcars
tail(mtcars,1)
#> mpg cyl disp hp drat wt qsec vs am gear carb
#> Volvo 142E 21.4 4 121 109 4.11 2.78 18.6 1 1 4 2
Created on 2020-04-02 by the reprex package (v0.3.0)
To see only the mpg values in mtcars, there are two ways
mtcars$mpg
#> [1] 21.0 21.0 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 17.8 16.4 17.3 15.2 10.4
#> [16] 10.4 14.7 32.4 30.4 33.9 21.5 15.5 15.2 13.3 19.2 27.3 26.0 30.4 15.8 19.7
#> [31] 15.0 21.4
mtcars[1]
#> mpg
#> Mazda RX4 21.0
#> Mazda RX4 Wag 21.0
#> Datsun 710 22.8
#> Hornet 4 Drive 21.4
#> Hornet Sportabout 18.7
#> Valiant 18.1
#> Duster 360 14.3
#> Merc 240D 24.4
#> Merc 230 22.8
#> Merc 280 19.2
#> Merc 280C 17.8
#> Merc 450SE 16.4
#> Merc 450SL 17.3
#> Merc 450SLC 15.2
#> Cadillac Fleetwood 10.4
#> Lincoln Continental 10.4
#> Chrysler Imperial 14.7
#> Fiat 128 32.4
#> Honda Civic 30.4
#> Toyota Corolla 33.9
#> Toyota Corona 21.5
#> Dodge Challenger 15.5
#> AMC Javelin 15.2
#> Camaro Z28 13.3
#> Pontiac Firebird 19.2
#> Fiat X1-9 27.3
#> Porsche 914-2 26.0
#> Lotus Europa 30.4
#> Ford Pantera L 15.8
#> Ferrari Dino 19.7
#> Maserati Bora 15.0
#> Volvo 142E 21.4
Created on 2020-04-02 by the reprex package (v0.3.0)
There' a function to provide a summary. Try an obvious function name
obvious(your_object$your_variable)
If you have data in row/col format, what's a reasonable guess for a function to return their names?