R is a powerful calculator with standard arithmetic operators:
# Addition
1 + 6## [1] 7
# Multiplication
2 * 6## [1] 12
# multiplication and division first, then addition and subtraction
2 * 6 + 1## [1] 13
# use of brackets
2 * (6 + 1)## [1] 14
# square root
sqrt(16)## [1] 4
# powers
16^0.5## [1] 4
2^2## [1] 4
# natural log
log(10)## [1] 2.302585
# decadic log
log10(10)## [1] 1
# log to base of 4
log(10, 4)## [1] 1.660964
# exponential
exp(2)## [1] 7.389056
# pi is a built-in constant
pi## [1] 3.141593
# but not e
e^2## Error in eval(expr, envir, enclos): object 'e' not found
If we want to refer to a result later on, we can give them a name.
a <- 1 + 6Here I assign (<-) the result of 1 + 6 to an object named a.
If you just type the name into the console R shows whats inside this object:
a## [1] 7
You can also do calculations with this object:
2 * a## [1] 14
Note, that R will overwrite objects:
a## [1] 7
a <- 2*a
a## [1] 14
If R doesn't know about an object you get the following error:
b## Error in eval(expr, envir, enclos): object 'b' not found
which says: "I looked for the object 'b', but could not find it"".
You can see objects that are available in the Environment pane of RStudio. Alternatively you can use the ls() function.