Using R as a Calculator
All complex analyses comprise sequences of multiple simple operations. To get acquainted with R and "build trust," please read about these operations you can implement in the R (RStudio) console and immediately see the results. Run the codes on your computer. Do you get the same outputs? Try changing some of the code to see how the outputs will change. You should be able to guess what kind of output you can get from any of these simple operations.
Introduction to R
Much of your time in R will be spent in the R interactive
console. This is where you will run all of your code, and can be a
useful environment to try out ideas before adding them to an R script
file. This console in RStudio is the same as the one you would get if
you typed in R in your command-line environment.
The first thing you will see in the R interactive session is a bunch of information, followed by a ">" and a blinking cursor. In many ways, this is similar to the shell environment you learned about during the shell lessons: it operates on the same idea of a "Read, evaluate, print loop": you type in commands, R tries to execute them, and then returns a result.
Using R as a calculator
The simplest thing you could do with R is to do arithmetic:
1 + 100
| Output |
|---|
|
And R will print out the answer with a preceding "[1]". Don't worry about this for now; we'll explain that later. For now, think of it as indicating output.
If you type in an incomplete command, R will wait for you to
complete it. If you are familiar with Unix Shell's bash, you may recognize this
behavior from bash.
> 1 +| Output |
|---|
|
Any time you hit return, and the R session shows a "+" instead of a ">", it means it's waiting for you to complete the command. If you want to cancel a command, you can hit Esc, and RStudio will give you back the ">" prompt.
Tip: Canceling commands
If you're using R from the command line instead of from within RStudio, you need to use Ctrl+C instead of Esc to cancel the command. This applies to Mac users as well!
Canceling a command isn't only useful for killing incomplete commands: you can also use it to tell R to stop running code (for example if it's taking much longer than you expect), or to get rid of the code you're currently writing.
Source: The Carpentries, https://swcarpentry.github.io/r-novice-gapminder/01-rstudio-intro/index.html
This work is licensed under a Creative Commons Attribution 4.0 License.