Basic Syntax and Variable Types

All objects in R have a variable type. The most common are:

• numeric: the object is a number
• character: the object contains letters
• logical: the object is either TRUE or FALSE
• NA: the object is blank (categorized as logical, but may be part of a character or numeric vector)

We can use the class() function on an object to check its variable type.

R uses symbols to represent:

• math operations (+, -, *, and / and follows the order of operations)
• logical operators (>, >=,<, <=, ==, and !=)
• joining logical operators (&, &&, | and ||)
• object assignment (<- or =)

The names of objects in R must follow 3 rules:

1. No spaces
2. No symbols other than . or _
3. Names must begin with a letter