#--------------------------------------------------------------------------.
#
# DON'T run two copies of RStudio at the same time (this might have been fixed) ####
#
# This issue only applies to the version of RStudio that you install on
# your personal machine.
#
# This does NOT apply to the online version of RStudio -
#
#--------------------------------------------------------------------------.
# Running two copies of RStudio at the same time can sometimes
# lead to problems. These problems are often not obvious. Therefore it is
# highly recommended that you do NOT run two copies of RStudio at the same
# time. If you notice strange things happening in RStudio, your first thing
# to check is that you don't have two copies of RStudio running
# simultaneously. If you do then shutdown one or both of them and see if the
# problem goes away.
#
# NOTE - this used to be a problem prior to 2023. However, I've noticed
# recently that it doesn't seem to be a problem anymore. However, if you notice
# that something weird is happening with RStudio, just make sure that you're
# not running RStudio in two different windows at the same time.1 1. Installing and using R
1.1 Getting access to the R software
Option 1: Installing R and RStudio on your computer
In order to install the software on your personal computer, you should install two different software products. The basic “R” software is installed first. The “base R” (i.e. R) is usable by itself but RStudio adds many features that makes using R much easier to use. I therefore recommend that you also install R Studio and use it for all of your work.
The “R Studio” program requires that the “R” program already be installed on your computer. Therefore it is important that you install these products in the following order.
install R first
Install RStudio next
For the specifics of how to install these products, see instructions on Canvas or see this webpage: https://rstudio-education.github.io/hopr/starting.html
WARNING - DON’T run two copies of RStudio at the same time (this might have been fixed)
Option 2: Using the online version of the software, i.e. https://posit.cloud/
https://posit.cloud hosts an online version of the RStudio program. You can get started simply with the “free” plan. It should be pretty easy to figure out how to do that by navigating to https://posit.cloud
When you login to posit.cloud you should create a “New RStudio Project”. You can then use that project for all of your R work.
posit.cloud also has several tutorials (i.e. “primers”). You can get to these by clicking the “primers” button. The first primer is called “The Basics”. “The Basics” primer is divided into “Visualization Basics” and “Programming Basics”. This class will focus on programming, not visualization. To get a better feel for R, you may optionally go throught the “programming basics” section of “The Basics” primer on posit.cloud
1.2 Using RStudio - window panes, arrow keys, ESC key, etc
What are RStudio “panes”
#-----------------------------------------------------------.
#
# RStudio "panes" ####
#
#-----------------------------------------------------------.
# RStudio's "window panes" - R Studio has 4 sections on the screen.
# When you first install RStudio the window panes are in the following
# configuration (this can be changed).
#
# upper left: source - use this to write commands that you want to save
# lower left: console - this is where all commands are acutally "run"
# upper right: environment, history - (more about this later)
# lower right: files, plots, help - (more about this later)
#
# If you don't see all the "panes" choose the following from the RStudio menu:
# View --> Panes --> Show All Panes
#
# You can change which info appears in which pane with the following RStudio menu:
# View --> Panes --> Pane Layout
# (I recommend that you don't change this until you get more experience with R).The “console” pane
#-----------------------------------------------------------.
#
# The "console" pane ####
#
#-----------------------------------------------------------.
# To write code you can type it directly in the "console" (lower left pane).
# You'll see the answer immediately. For example, if you type
# 3+2 into the console, you will see the answer 5.
3+2[1] 5Modifying previous commands (use the arrow keys)
#-----------------------------------------------------------.
#
# Modifying previous commands (use the arrow keys) ####
#
#-----------------------------------------------------------.
# If you want to modify a command that you previously typed, you can use the
# up-arrow and down-arrow to search for commands that you previously typed.
# When you find the command that you want, you can
# (a) either press ENTER to run it again
# (b) or use the left-arrow, right-arrow, backspace, delete (windows) keys to edit the command.
#
# For example, in the console,
# (1) use the up arrow, and change 3+2 to 4+2 then hit ENTER to get the new value.
# (2) use the up-arrow and down-arrow to see your history of commands.
#
# You can also see all of your previous commands in the "history" pane (which is by default
# in the upper right hand corner of your screen). You can double-click any command to show
# it in the console.insert key (on Windows)
#-----------------------------------------------------------.
#
# insert key (on Windows) ####
#
#-----------------------------------------------------------.
# On Windows, the "insert" key will switch between "overstrike" mode and "insert" mode.
# If you see that you are "typing over" existing text instead of inserting new text
# then press the "insert key" to switch to "insert mode".Erasing commands - ESC key
#-----------------------------------------------------------.
# Erasing commands - ESC key ####
#
# Clearing the console - ctrl-L (windows) or cmd-L (mac)
#
#-----------------------------------------------------------.
# If you type a long line that you want to erase, press the ESC key.
# If you want to clear the entire console window, press ctrl-L (windows) or cmd-L (mac)The “source” pane - for saving code
#-----------------------------------------------------------.
#
# The "source" pane - for saving code ####
#
#-----------------------------------------------------------.
# To write code that you want to save you need to create a new "R Script" file.
# Choose the following menu choice:
# File --> New File --> R Script
#
# This will open a new file in the "source" pane (which is by default in
# the upper-left corner of the screen).
#
# You can type any commands in this file.
#
# You can run any command that is in a script file in the following ways:
# (a) place your cursor on the line you want to executed and then
# press ctrl-ENTER (on Windows) or cmd-ENTER (on Mac)
#
# (b) to run several commands, select all of the lines you want to execute
# then press ctrl-ENTER (windows) or cmd-ENTER (mac)
#
# (c) you can even select just PART of a line to execute JUST THAT PART.
# For example, if the script contains the line:
# 3+4*5-1
# and you highlight JUST the 4*5 and press ctrl-ENTER/cmd-ENTER you will see the answer 20.
# This even works with code in a comment. Try it with the line 3+4*5-1 above.
#
# (d) press ctrl-a (windows) or cmd-a (mac) to select all of the code
# then press ctrl-ENTER (windows) or cmd-ENTER (mac) to run all of the code.
# To save changes you make to the file - press ctrl-s (windows) or cmd-s (mac)
#
# These files are saved with a .R (captial "R") filename extension.
# If you don't know what a filename extension is, watch these videos
# (or search for other videos or explanations ...)
# Windows Filename Extensions: https://www.youtube.com/watch?v=m58rkfVRDlc
# Mac Filename Extensions: https://www.youtube.com/watch?v=mYNchWitkyg
#
# If you double-click on the file, it should open up RStudio to display the file.Other RStudio features
# Other RStudio features
#
# There are many different RStudio features. You can explore the various
# menus and tabs to learn more. Don't be afraid to try things. Search online
# for explanations.1.3 Do NOT use Word (or similar programs) to type your commands
###########################################################################.
###########################################################################.
#
# Do NOT use Word (or similar programs) to type your commands ####
#
###########################################################################.
###########################################################################.
# It is important to note that Microsoft Word and other similar programs will
# sometimes replace minus signs (i.e. "-") with "long dash" characters (these
# look like minus signs but are a little longer). Word also may quotes (")
# with "smart quote" characters. All of these changes will make a command
# that "looks" correct, not work when you paste the code into R.
#
# The moral of the story is NEVER USE WORD to type R code.1.4 Using R to do basic arithmetic
############################################################.
############################################################.
#
# Using R to do basic arithmetic ####
#
############################################################.
############################################################.
# R can be used as a simple "calculator"
3 + 2 # This will show 5. The part after the # is a "comment" that is ignored.[1] 5# In general, extra spaces are meaningless. They can be added to improve readability of your code.
# The following two command will produce the exact same answers.
3+2-100+50 # you don't need spaces[1] -45 3 + 2 - 100 + 50 # but spaces do not change the result[1] -45# Exponents are written using the caret character, ^ (above the 6 on most keyboards).
2^3 # ie. "2 to the power of 3", i.e. 8[1] 8# Division is done using the FORWARD SLASH (i.e. /)
# (The backslash (i.e. "\" will NOT work for division)
10/4 # this will show 2.5[1] 2.5#10\4 # ERROR - don't use a backslash!Order of operations
# R follows the "order of operations" in math (i.e. PEMDAS), specifically ...
# FIRST: All parentheses are done first
# SECOND: All exponents are done next
# THIRD: All multiplications and divisions are done next (starting from the
# leftmost * or / and working to the right)
# FOURTH: All additions and subtractions are done (from left to right)
# Examples
3+2*5 # 13, not 30, i.e. the * is done before the +[1] 13# In the following command: 100-12/3*4/2+10
# the answer is 102.
# It gets calculated as follows:
#
# original --> 100-12/3*4/2+10
#
# first step: 12/3 becomes 4 --> 100-(4)*4/2+10
#
# second step: 4*4 becomes 16 --> 100-(16)/2+10
#
# third step: 16/2 becomes 8 --> 100-(8)+10
#
# fourth step: 100-8 become 92 --> (92)+10
#
# last step: 92+10 becomes 102 --> 102
100-12/3*4/2+10 # This becomes 102 (see explanation in comments above)[1] 102Do NOT use commas, dollar signs, etc in numbers
#-----------------------------------------------------------.
#
# Do NOT use commas, dollar signs, etc in numbers ####
#
#-----------------------------------------------------------.
# R does NOT recognize commas, dollar signs, etc as part of numbers.
3.25 + 2.00 # 5.25[1] 5.25# $3.25 + $2.00 # ERROR
50000 + 20000 # 70000[1] 70000# 50,000 + 20,000 # ERROR1.5 R prompts you with “+” signs if it expects you to type more
####################################################################.
# R prompts you with "+" signs if it expects you to type more ... ####
####################################################################.
#
# If you write a line of code in the Console window
# and press ENTER before you finish typing a full command,
# R will display a "+" sign to indicate
# that R is expecting you to enter more info. For example
#
# > 100 /
# + 4
# [1] 25
#
# These "+" signs do NOT have anything to do with "addition".
# They are just prompts to indicate that you need to enter more information.
###########################################################.1.6 PRESS ESC TO CANCEL A COMMAND
####################################################################.
# PRESS ESC TO CANCEL A COMMAND (and get the "> prompt" back)
####################################################################.
# If you keep pressing ENTER, without finishing the command you will
# simply get more "+ sign prompts" (since R is still waiting for you
# to finish the command). If you press the ESC key the command will be
# cancelled and you will once again get the ">" prompt so that you can continue.
# EXAMPLE:
#
# > 100 / # pressed ENTER
# + # pressed ENTER
# + # pressed ENTER
# + # pressed ENTER
# + # etc.
# +
# + # pressed ESC (this cancels the command)
# >
#
# This works for any line of code.
# If you press ESC in the Console window while you are typing a line
# of code, the line of code is "cancelled". For example:
#
# > 3+2*123/5-7 (press ESC) # NOTHING HAPPENS - LINE IS ERASED
# >
####################################################################.1.7 R Studio HotKeys - SCRIPT window
Pressing ctrl-ENTER (win) or cmd-ENTER (mac) runs all code that is currently highlighted in the Script window. The output will appear in the console window. (also see shift-arrow-keys below). If no code is highlighted then this runs just the line of code where the cursor is in the script window.
Pressing shift-arrow-keys in the script window extends the highlight in the direction of the arrow key. This is a very quick way to highlight a few lines of code. Press shift while holding the down arrow (or up arrow) to highlight just a few lines of code. Then if you press ctrl-ENTER (win) or cmd-ENTER (mac) you can run just those lines of code.
1.8 R Studio HotKeys - CONSOLE window
Pressing ctrl-L clears the “console” window.
Pressing ESC in the console window clears the current command that you typed. Use this if you typed a long command and you want to erase it before pressing ENTER.
Pressing the left/right arrows move in the console window moves left/right in the current line of code. This allows you to edit the line.
Pressint the up/down arrows in the console windows brings back commands that were typed earlier/later. This allows you to quickly rerun commands that you have typed earlier or to modify earlier commands. (Also see the ““history” tab in the upper right window pane.)