We're almost done with Part 1 of the course! We've covered quite a lot of information here, so let's do a quick recap.

R knows how to work with number and text values. With numeric values, you can perform various calculations: addition (5+4), subtraction (5-1), multiplication (15*4), division (5/4). Text values are surrounded with single or double quotes ("Mary" or 'Mary').

The results of calculations can be stored in a variable:

weight <- 75

Variables can be used in further calculations, e.g.:

weight + 10

You can compare values saved in variables with other values using comparison operators (e.g. height < 160). Such comparisons return a single logical value: TRUE or FALSE.

R has many built-in functions that perform all kinds of predefined calculations. A function is called by its name. In parentheses, you pass in the arguments to the function:

round(15.2)

There are functions that work with number values (like round) and those that work with text values (nchar, substr). You can get more information about a function by using the help operator followed by the function name, like so:

?functionname

You can also write comments in R. A comment is anything that follows # on a single line. These serve no other purpose than to document your code. That's about it! It's time to test what you've learned. Ready?