Hi all, this section is about introduction to R codes.
- Click here to download R.
- Click here to download RStudio.
Copy the codes in the grey region onto your R console to run them.
1. Expressions
"Hello World!"
## [1] "Hello World!"
1+1
## [1] 2
print("I'm learning R")
## [1] "I'm learning R"
3^2
## [1] 9
2. Testing logical values (returns “TRUE” or “FALSE”)
8>6
## [1] TRUE
1+3 == 3
## [1] FALSE
2 <= 3
## [1] TRUE
3. R Scripts - download the “start.R” sample here
# loads the script
source("start.R")
4. Variables
# assigns 8 to x
x <- 8
# print value of x
x
## [1] 8
# use x like a variable in expressions
x/2
## [1] 4
# "=" sign can be used to assign value to variables too
y = "I'm learning R!"
y
## [1] "I'm learning R!"
5. Functions
# sum
sum(1,2,3)
## [1] 6
# square root
sqrt(25)
## [1] 5
# repeat
rep("hi", 20)
## [1] "hi" "hi" "hi" "hi" "hi" "hi" "hi" "hi" "hi" "hi" "hi" "hi" "hi" "hi"
## [15] "hi" "hi" "hi" "hi" "hi" "hi"
6. Examples on getting help
# keying "?" infront of functions
?sum
?sqrt
?rep
# keying "??" infront of unknown functions or packages
??qplot
??ggplot2