Primitive Data Types

Before we can begin programming, which—at the most basic level—involves manipulating data, we need to learn what kinds of data we can manipulate. All programming languages have built-in primitive data types. Primitive data types are a programming language's fundamental building blocks. They are types of objects, Ruby's representation of data. Objects are the nouns of Ruby.

Ruby has five primitive data types, but you'll only need to learn the following four to pass the online challenge.

Strings: A string is a sequence of characters. Strings are denoted by enclosing double ("") or single ('') quotation marks. "dog", "3 logs", and "the brown dog jumped over the 3 logs" are all strings. Strings can be of any length. "" is an empty string (a string of length zero). Remember to wrap strings in quotation marks. Otherwise Ruby will misinterpret the code.

Numbers: In Ruby, we call any whole number—positive or negative (including 0)—an integer. 9 and -4 are both integers. Fractional numbers (with decimal points) such as 3.1415 are called floats or floating point numbers. Some mathematical operations in Ruby function differently depending on whether the number is a float or an integer. By the way, don't use include commas in integers. Writing 4,000 instead of 4000 will confuse Ruby.

Booleans: There are only two boolean values: true and false. Booleans provide the core logic of computer programs. 4 > 5 is false, and 4 < 5 is true. Note that booleans are case sensitive. true is a boolean, True is not. And "true" is a string, not a boolean.

Nil: Ruby represents nothingness with the keyword nil. Sometimes the absence of data is as important as data itself.