Hi! I am Mike Marin
and in this video we'll talk about writing scripts of code
in R. scripts are useful as they allow one to easily pick up where they left
off on a project and progressively
build and refine code and analyses. they also allow one to easily reproduce
analyses that were run earlier. a script is a set of commands that usually includes
some commenting on what each piece of code is intended to do
I've already written a bit of script as you can see here
recall that the number sign or hash (#)
can be used to prompt R to ignore anything that immediately follows
the simplest way to get started and the least efficient way of doing things
is to simply cut and paste snippets of code
and paste them into R. here I'll go ahead
and copy this and paste it into R
a better approach
is to have this script appear within RStudio . an R script should be saved
with the extension ".R"
one can create a new script
using the menu options in R. you can select "File"
and then "New" and here you see an option for new
"R script" or one may also
open an existing R script using the menu
here we can select "Open File" and then we can open up
the R script directly from here. we can now see
this script of code in RStudio source editor
we can also adjust the size of the windows
in RStudio to our desired size.
now we can see
in here is where we're able to write new code
and add to our existing script as we progress through working with our data
if you would like to submit a line of code
rather than copying this code and pasting it into the R Console
we can place the cursor on the line of code we would like to have submitted
and then we can either click on this "Run" option to have this piece of code
submitted
you'll notice that after submitting a line of code
the cursor would jump down to the next line. we can also submit pieces of code
using keyboard shortcuts: the shortcut to enter this code
would be "command & enter"; you'll also notice
that if we submit one of our commented lines R will ignore this.
sometimes it will be the case
that we would like to submit multiple lines of code
for example maybe to start, we would like to
set our working directory and load the previous one
all at once. to do so we can highlight
or select all the pieces of code we would like to have entered
and then click on "Run" or
we can use the keyboard shortcut of "command & enter"
it's worth noting
that most of the functionality of a regular text editor
can be found in RStudio script editor. for example
under the "Edit" menu we can do a "Find and Replace..."
there are also few other
useful menu options. we can also see under the "Code" menu
there's this "Comment /Uncomment Lines" this will allow us to take
an entire section of code and add comments
that is the number sign or hash sign (#) in front of them
or take an entire section and remove the number or hash signs (#)
let's go ahead and load
our previous workspace. we place the cursor on this line
and click "Run" to submit this piece of code. now is the point where we would continue along
with the analysis we've been working on let's suppose that as a next step
we decide to add a piece of code asking for the class
of the variable Gender.
to submit this we can click on "Run" and you will notice
ooops! we made a typo here. we can just go back
and correct this in our script
and then resubmit the piece of code. once we have the code
as we like then we can go ahead and save this script
now there's one handy feature in RStudio that we have not talked about yet
and that's the use the "Tab" key. you can type
the start of an R command and then hit the "Tab" key
and R will return to you a list of suggestions of what you may be looking for
for example we want to calculate the mean we can select this
and now we found the command we like and we saved ourselves some typing time
it's worth noting that the use of the Tab key
will also work directly in the R Console
and it will also work to autocomplete objects that you've created
for example "Lun" we can hit the Tab key
and we can see RStudio returns to us options of were you looking for
LungCapData or the measurement LungCap
which is stored inside the object LungCapData
here let's take a look at lung capacities for person 1 up to 5
well not completely necessary
use of the Tab key can help save some time typing
or help you find the name of a command if you don't quite remember what it was
now once you're done working for the day you're going to want to go ahead and
save your script
we can do this by placing the cursor in the window where our script is located
going up to "File" and then "Save" or "Save As..."
depending on if this is a newly created script or one with already existing name.
I'll go ahead and save this
you may also wish to save your workspace image depending on how you like to work
and how you like to organize your work I'm gonna go ahead
and submit this line of code ("save.image") to save the workspace image as well
I hope this video has helped you see the benefits of using a script in R
thanks for watching this video and make sure to check out my other instructional videos