Functions

Built-in Functions

A built-in function is one that you don’t need to install and load a package to use. To learn how to use a function you can use the help() function or the Help tab in RStudio. help() takes one parameter, the name of the function that you want information about (e.g., help(abs)) or type the name into the search box on the Help tab. Familiarize yourself with the built-in functions abs(), round(), sqrt(), tolower(), and toupper(). Use these built-in functions to print the following items:

1. The absolute value of -15.5.
2. 4.483847 rounded to one decimal place. The function round() takes two arguments, the number to be rounded and the number of decimal places.
3. 3.8 rounded to the nearest integer. You don’t have to specify the number of decimal places in this case if you don’t want to, because round() will default to using 0 if the second argument is not provided. Look at help(round) or ?round to see how this is indicated.
4. "species" in all capital letters.
5. "SPECIES" in all lower case letters.
6. Assign the value of the square root of 2.6 to a variable. Then round the variable you’ve created to 2 decimal places and assign it to another variable. Print out the rounded value.

Challenge: Do the same thing as task 6 (immediately above), but instead of creating the intermediate variable, perform both the square root and the round on a single line by putting the sqrt() call inside the round() call.