Constants

If you're coming from other programming languages, Ruby handles constants differently than what you may be used to. Constants, in general, take values that do not change through the entire application. The syntax is to use all capital letters while naming your constant so that the application knows how to handle it. For example, to set a constant to hold a baseball team, you would declare it this way:

TEAM = "Angels" 

Typically, other programming languages will not allow you to change the value of TEAM. However, Ruby does not hold you back, and it takes the last value assigned to the constant. In the preceding example, I can change its value to:

TEAM = "Athletics" 

Other programming languages would either throw an error or would print the Angels value. However, Ruby prints the Athletics value because that is the last value assigned to the TEAM variable. Also, it gives a warning message which says that the constant was already initialized and was changed because changing a constant is considered a poor programming practice. However, it still lets you make that change and follows the Ruby convention of trusting the developer to make the right programming decision. So, be careful while using constants in Ruby since they can be overridden.